Beijing, China

China University of Mining and Technology colloquially 矿大 is a national key university under the direct supervision of the Ministry of Education of China as well as a Project 211 and Project 985 university of China. The university consists of two parts, one located in Xuzhou, Jiangsu Province, the other located in Beijing with the name China University of Mining and Technology, Beijing . The latter is formerly the Graduate School of CUMT. CUMT is a leading multi-disciplinary polytechnic university with mining features. Wikipedia.


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Patent
China University of Mining and Technology | Date: 2015-08-06

A Co_(3)W_(3)C fishbone-like hard phase-reinforced Fe-based wear-resistant coating and the preparation thereof, which belongs to the field of a wear-resistant coating on the surface of a material and a preparation method thereof. The wear-resistant coating comprises: 1.89-3.77% of C, 5.4-11.7% of Cr, 3.3-7.15% of Ni, 28.81-57.83% of W, 4.2-8.4% of Co, 0.03-0.065% of Si and the balance of Fe. The preparation process of the wear-resistant coating comprises: (1) before plasma cladding, pretreating a matrix; (2) pretreating an iron-based alloy powder; and (3) adjusting the process parameters of plasma cladding, preparing a cladding layer with a predetermined width and a predetermined thickness, and naturally cooling same down in air. The wear-resistant coating is simple in process; the prepared cladding layer has a strong metallurgical bonding property with the matrix structure, so that the best performance matching between the ceramic phase of the cladding layer and the matrix can be achieved; a fishbone-like hard phase Co_(3)W_(3)C has a very high hardness value and plays the role of a framework in the frictional process to reduce the wear of the matrix structure, thereby achieving an excellent wear resistance; plasma cladding is convenient to operate, and can be automatized; and the prepared wear-resistant layer is high in size precision and can be widely applied to surface modification of mechanical parts.


Patent
China University of Mining and Technology | Date: 2014-11-19

A device and method of using infrared radiation to observe coal rock fracture development processes, for use in experiments to monitor coal rock fracture development using infrared radiation comprises three telescopic box bodies sleeved together. An infrared thermal imager connected to a computer is arranged at the front end of the telescopic box bodies, and a light-blocking plate is installed on a rear end. The distance between a coal rock test block and a lens of the infrared thermal imager can be freely adjusted via the three telescopic box bodies. The telescopic box bodies are installed on a rock press, and a loading test is performed on the coal rock test block.


Patent
BEIJING IVY TECHNOLOGY Co., China University of Mining and Technology | Date: 2016-08-25

The present disclosure discloses a fracture AVO inversion method for a fractured medium, wherein, said method includes: acquiring seismic data from the fractured medium; obtaining a reflection coefficient of the fractured medium, by an AVO inversion for the seismic data based on a newly-built equation. The present disclosure also provides a fracture AVO inversion apparatus and device for a fractured medium. The present invention can flexibly and accurately obtain properties of a fractured medium with impedance contrast (rock properties of the host media plus properties of thee fracture).


Altman E.,Weizmann Institute of Science | Sieberer L.M.,University of Innsbruck | Chen L.,China University of Mining and Technology | Diehl S.,University of Innsbruck | And 2 more authors.
Physical Review X | Year: 2015

Fluids of exciton polaritons, excitations of two-dimensional quantum wells in optical cavities, show collective phenomena akin to Bose condensation. However, a fundamental difference from standard condensates stems from the finite lifetime of these excitations, which necessitates continuous driving to maintain a steady state. A basic question is whether a two-dimensional condensate with long-range algebraic correlations can exist under these nonequilibrium conditions. Here, we show that such driven two-dimensional Bose systems cannot exhibit algebraic superfluid order except in low-symmetry, strongly anisotropic systems. Our result implies, in particular, that recent apparent evidence for Bose condensation of exciton polaritons must be an intermediate-scale crossover phenomenon, while the true long-distance correlations fall off exponentially. We obtain these results through a mapping of the long-wavelength condensate dynamics onto the anisotropic Kardar-Parisi-Zhang equation.


Yang X.-J.,China University of Mining and Technology | Yang X.-J.,Qujing Normal University | Srivastava H.M.,University of Victoria | He J.-H.,Soochow University of China | And 3 more authors.
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2013

In this Letter, we propose to use the Cantor-type cylindrical-coordinate method in order to investigate a family of local fractional differential operators on Cantor sets. Some testing examples are given to illustrate the capability of the proposed method for the heat-conduction equation on a Cantor set and the damped wave equation in fractal strings. It is seen to be a powerful tool to convert differential equations on Cantor sets from Cantorian-coordinate systems to Cantor-type cylindrical-coordinate systems. © 2013 Elsevier B.V. All rights reserved.


Chen L.,China University of Mining and Technology | Toner J.,University of Oregon
Physical Review Letters | Year: 2013

We present a theory of moving stripes ("polar active smectics"), both with and without number conservation. The latter is described by a compact anisotropic Kardar-Parisi-Zhang equation, which implies smectic order is quasilong ranged in d=2 and long ranged in d=3. In d=2 the smectic disorders via a Kosterlitz-Thouless transition, which can be driven by either increasing the noise or varying certain nonlinearities. For the number-conserving case, giant number fluctuations are greatly suppressed by the smectic order, which is long ranged in d=3. Nonlinear effects become important in d=2. © 2013 American Physical Society.


Ma C.,Nanjing Forestry University | Zhu H.,China University of Mining and Technology
Tribology International | Year: 2011

The influence of surface texture in the form of the elliptical-shape dimples with various depths, diameters, area ratios and different operation parameters on friction coefficient has been investigated under conditions of hydrodynamic lubrication. The results show that, the larger the optimum diameter, the larger the corresponding optimum depth becomes; the optimum area ratio is not bound up with the texture parameters and operating parameters; the optimum depth increased while the optimum diameter decreased as the velocity became larger and the load became smaller. A model for the optimum design of textured surface was built and then validated by the experiments. © 2011 Elsevier Ltd. All rights reserved.


Talhelm T.,University of Virginia | Haidt J.,New York University | Oishi S.,University of Virginia | Zhang X.,Beijing Normal University | And 2 more authors.
Personality and Social Psychology Bulletin | Year: 2015

Henrich, Heine, and Norenzayan summarized cultural differences in psychology and argued that people from one particular culture are outliers: people from societies that are Western, educated, industrialized, rich, and democratic (WEIRD). This study shows that liberals think WEIRDer than conservatives. In five studies with more than 5,000 participants, we found that liberals think more analytically (an element of WEIRD thought) than moderates and conservatives. Study 3 replicates this finding in the very different political culture of China, although it held only for people in more modernized urban centers. These results suggest that liberals and conservatives in the same country think as if they were from different cultures. Studies 4 to 5 show that briefly training people to think analytically causes them to form more liberal opinions, whereas training them to think holistically causes shifts to more conservative opinions. © 2014 by the Society for Personality and Social Psychology, Inc.


Zhang B.,China University of Mining and Technology | Chen G.Q.,Peking University | Chen G.Q.,King Abdulaziz University
Renewable and Sustainable Energy Reviews | Year: 2014

In contrast to the ever-increasing focus on China's CO2 emissions, little attention has been given to its CH4 emissions, the second largest greenhouse gas. Presented in this paper is a comprehensive assessment of the CH4 emissions in Mainland China by source and region based on the latest statistical data and research literatures available. The total CH4 emission in China 2007 is estimated as 38.6 Tg, one and a half times of that in USA. Even by the lower IPCC global warming potential (GWP) factor of 25, it corresponds to 964.1 Mt CO2-eq, in magnitude up to one seventh of China's CO2 emission and greater than the nationwide gross CO2 emissions in Australia, Canada, and Germany in 2007. As the leading emission source, energy activities are responsible for 45.3% of the total emission, agricultural activities contribute a comparable share of 40.9%, followed by waste management of 13.8%. Among all the 11 major emission sources, coal mining (38.3% of the total), enteric fermentation (21.4%) and rice cultivation (14.4%) essentially shape the CH4 emission profile for China, quite different from that for USA which is characterized by prominent emissions from enteric fermentation, municipal solid waste landfill and natural gas leakage. The Western and Central areas contribute 70.9% of the total nationwide emission and Shanxi is the largest regional CH4 emitter with an amount of 4.6 Tg. The five regions of Xizang (Tibet), Shanxi, Qinghai, Ningxia, and Guizhou are identified with the largest emissions per-capita and emission intensities. In contrast to the focused areas of CO 2 emission reduction mainly in the energy-intensive eastern regions, the mitigation potential of CH4 emissions in the western and central regions is huge by integrating emission quantity and structure with emission per-capita and emission intensity at the regional level. Corresponding policy-making implications for CH4 emission mitigation in China are addressed. © 2013 Elsevier Ltd.


Tian H.,CAS Guangzhou Institute of Geochemistry | Pan L.,CAS Guangzhou Institute of Geochemistry | Xiao X.,CAS Guangzhou Institute of Geochemistry | Wilkins R.W.T.,CSIRO | And 2 more authors.
Marine and Petroleum Geology | Year: 2013

Although Lower Silurian black shales within and around the Sichuan Basin have received renewed attention during the past few years because of their potential prospectivity for shale gas, studies associated with shale gas reservoir evaluation are still rare. In this study, eight black shale core samples were collected from a well drilled recently in the Chuandong Thrust Fold Belt, southwestern China, and their geochemistry and pore structures were investigated using low pressure N2 adsorption analysis and field emission scanning electron microscopy (FE-SEM) observations. The results show that the black shales have total organic carbon (TOC) values ranging from 1.01% to 3.98% and their equivalent vitrinite reflectance values are in the range of 2.84%-3.05%. Both mineral matrix and organic matter pores are well developed with pore sizes ranging from several to several hundred nanometers. The total porosity for the eight samples ranges from 2.60% to 4.74% and the percentages of organic matter pores are estimated to be in the range of 31%-62%. The total surface area ranges from 5.06m2/g to 19.32m2/g and the micropore (<2nm) surface area estimated by the t-plot method ranges from 3.13m2/g to 9.27m2/g. The TOC values have positive relationships with the total porosity, total surface area and the micropore (<2nm) volume and surface area, indicating TOC may be an effective parameter for shale gas reservoir evaluation in the studied area. © 2013 Elsevier Ltd.


Zhou Y.,China University of Mining and Technology | Zhu H.,China University of Mining and Technology | Tang W.,China University of Mining and Technology | Ma C.,Nanjing Forestry University | Zhang W.,China University of Mining and Technology
Tribology International | Year: 2012

In this paper, based on the Reynolds equation and the dynamic operation conditions of cylinder liner and piston ring of CY6102 type diesel engine, a theoretical model of the load carrying capacity and film thickness for the first compressed ring were developed. Based on the theoretical models, the effects of the texturing parameters on the load carrying capacity and film thickness were investigated under different velocities, and the ranges of optimum texturing parameters were found. An optimal texturing design method on cylinder liner was proposed. It shows that on cylinder liner, texturing with variable parameters in different velocity ranges can produce higher load carrying capacity and film thickness than that with invariable parameters. © 2012 Elsevier Ltd.


Zhang B.,China University of Mining and Technology | Zhang B.,Peking University | Chen G.Q.,Peking University | Li J.S.,Peking University | Tao L.,Indian Institute of Technology Madras
Renewable and Sustainable Energy Reviews | Year: 2014

As the largest CH4 emitter, China produces CH4 at an increasing rate, especially from its energy activities. Presented in this paper is a detailed inventory and analysis of CH4 emissions from energy activities in China from 1980 to 2007 covering all the significant sources. The total energy-related CH4 emissions in China tripled during the period with an average annual increase rate of 4.7% and reached 21,943.1 Gg in 2007, 2.4 times of that in USA. As the largest emission source, coal mining increased its share from 69.2% (4559.5 Gg) in 1980 to 85.8% (18,825.5 Gg) in 2007; The second biggest source was fuel combustion, mainly bio-fuel combustion (2370.3 Gg in 2007); Oil and natural gas system leakage was a minor source but at a rapidly increasing rate. This transient emission structure is quite different from the steady structure of USA, which is dominated by the fugitive emissions from natural gas and oil systems. According to the lower IPCC Global Warming Potential, the annual energy-related CH4 emissions were equivalent to 9.1%-11.7% of China's energy-related CO2 emissions, amounting to 548.6 Mt CO2-eq in 2007 which is greater than the nationwide gross CO2 emissions in many developed countries. © 2013 Elsevier Ltd. All rights reserved.


Wu L.-X.,Beijing Normal University | Wu L.-X.,China University of Mining and Technology | Qin K.,China University of Mining and Technology | Liu S.-J.,Northeastern University China
Proceedings of the IEEE | Year: 2012

Although earthquakes are difficult to be predicted because of the complexity of the Earth system and the uncertainty of seismogenic processes, GEOSS provides multiple sources of observation data and brings a possibility to extract a thermal anomaly that would have a significant effect on earthquake prediction. Referring to the analysis on the lithosphere-coversphere-atmosphere (LCA) coupling due to stress enhancement in seismogenic zone, six thermal parameters, including surface latent heat flux (SLHF), thermal infrared radiation (TIR), outgoing longwave radiation (OLR), diurnal temperature range (DTR), atmospheric temperature, and skin temperature, are selected for GEOSS-based earthquake anomaly recognition (EAR). The inherent relations between the six thermal parameters are preliminarily introduced in consideration of possible LCA coupling. With overquantity, quasi-synchronism, and geo-consistency being defined as three rules for data mining, a deviation-time-space-thermal (DTS-T) EAR method as well as its procedures are developed in this paper. With 2008 M7.3 Yutian earthquake, China, 2008 M8.0 Wenchuan earthquake, China, and 2010 M7.1 Christchurch earthquake, New Zealand, being examples of tectonic earthquakes, the technical procedures of DTS-T method are demonstrated, which show that the obtained compositive thermal anomaly has a significant effect on earthquake prediction. © 2012 IEEE.


Li H.-J.,China University of Mining and Technology | Xiao B.,China Institute of Technology
Kongzhi Lilun Yu Yingyong/Control Theory and Applications | Year: 2012

This paper brings forward a multistep predictive model based on the recurrent backpropagation (BP) neural network for the control systems with strong nonlinearity and multiple set-points. By analyzing the internal mathematical relation of the predictive model, we select a quadratic function as the objective function for the multistep predictive controller. For this objective function, we compute the Jacobian matrix and Hessian matrix of the control sequence, and design the receding horizon optimization strategy using Newton-Rhapson algorithm, thus, constituting a nonlinear multistep model predictive controller. Simulation results show desirable performances of the model predictive controller.


Zhang B.,China University of Mining and Technology | Qiao H.,University of Chinese Academy of Sciences | Chen B.,Beijing Normal University
Ecological Modelling | Year: 2015

Consumption demands in China's megacities not only cause energy resource extraction within their own jurisdictional boundaries, but also impose huge energy resource requirements to other regions via interregional supply chains. This paper presents a multi-regional input-output analysis of energy uses embodied in final demand and interregional trade of China's four direct-controlled municipalities, with the recently available Chinese 2007 multi-regional input-output table. The total embodied energy uses (EEUs) of Beijing, Tianjin, Shanghai and Chongqing are 59.1, 60.0, 136.7 and 50.4. Mtce in 2007, respectively. Shanghai has the highest per capita EEUs with an amount of 7.4. tce, followed by Tianjin (5.4. tce), Beijing (3.6. tce) and Chongqing (1.8. tce). Investment is the leading final demand category and accounts for respectively 53.1% and 55.8% of the total EEUs in Beijing and Chongqing. Meanwhile, the shares of energy uses embodied in exports are especially high in Tianjin and Shanghai, due to their location advantages and great economic openness. 98.9%, 92.1%, 51.2% and 35.6% of the EEUs in Shanghai, Beijing, Tianjin and Chongqing are imported from China's other regions, respectively. Shanxi, Inner Mongolia, Hebei, Shaanxi, Heilongjiang and Xinjiang are the important "energy-saving helpers" for these megacities. The largest interregional net embodied energy-import sector is construction for all the four municipalities. Considering the embodied energy uses in urban ecosystems is important for policy makers to recognize visible and hidden energy uses within city boundaries and along the entire supply chains and address cross-boundary potentials for energy saving at the regional, national and global supply chains. © 2014 Elsevier B.V.


Yang X.-J.,China University of Mining and Technology | Srivastava H.M.,University of Victoria | Cattani C.,University of Salerno
Romanian Reports in Physics | Year: 2015

In this article, we propose and apply a local fractional homotopy perturbation method, which is and extended form of the classical homotopy perturbation method. We discuss convergence aspect of the technique and present two illustrative examples to show the efficiency of the proposed method in order to find the approximate solutions for some local fractional differential equations arising in mathematical physics. © 2015, Editura Academiei Romane. All rights reserved.


Zhou T.,China University of Mining and Technology | Sun W.,China University of Mining and Technology
IEEE Transactions on Sustainable Energy | Year: 2014

In capacity optimization of hybrid energy storage station (HESS) in wind/solar generation system, how to make full use of wind and solar energy by effectively reducing the investment and operation costs based on the load demand through allocating suitable capacity of HESS is an optimization problem. The optimization objective is to minimize one-time investment and operation costs in the whole life cycle, the constraints are utilization rate, and reliability of power supply. In this paper, mathematical models of wind/solar generation systems, battery, and supercapacitor are built, the objective optimization function of HESS is proposed, and various constraints are considered. To solve the optimization problem, improved simulated annealing particle swarm optimization algorithm is proposed by introducing the simulated annealing idea into particle swarm algorithm. The new algorithm enhance the ability to escape from local optimum and improve the diversity of particle swarm, then help to avoid prematurity and enhance the global searching ability of the algorithm. With the example system, the optimization results show that the convergence of new algorithm is faster than the traditional particle swarm optimization algorithm and its cost optimization is better, which demonstrated the correctness and validity of the proposed models and algorithms. This method can provide a reference for the capacity optimization of HESS in wind/solar generation system. © 2010-2012 IEEE.


Dai S.,China University of Mining and Technology | Ren D.,China University of Mining and Technology | Chou C.-L.,Illinois State Geological Survey | Finkelman R.B.,University of Texas at Dallas | And 2 more authors.
International Journal of Coal Geology | Year: 2012

China will continue to be one of the largest coal producers and users in the world. The high volume of coal use in China has focused attention on the amounts of toxic trace elements released from coal combustions and also the valuable trace elements extracted or potentially utilized from coal ash.Compared to world coals, Chinese coals have normal background values for most trace elements, with the exception of higher Li (31.8. μg/g), Zr (89.5. μg/g), Nb (9.44. μg/g), Ta (0.62. μg/g), Hf (3.71. μg/g), Th (5.84. μg/g), and rare earth elements (∑. La-Lu. +. Y, 136. μg/g). This is not only due to the higher ash yields of Chinese coals but also to alkali volcanic ashes found in some southwestern coals. The background values of toxic elements of Hg (0.163. μg/g), As (3.79. μg/g), and F (130. μg/g) in Chinese coals are comparable to coals from most other countries.The genetic types for trace-element enrichment of Chinese coals include source-rock- controlled, marine-environment-controlled, hydrothermal-fluid-controlled (including magmatic-, low-temperature-hydrothermal-fluid-, and submarine-exhalation-controlled subtypes), groundwater-controlled, and volcanic-ash-controlled. The background values of trace elements were dominated by sediment source regions. Low-temperature hydrothermal fluid was one of the major factors for the local enrichment of trace elements in southwestern China.Serious human health problems caused by indoor combustion of coal in China include endemic fluorosis, arsenosis, selenosis, and lung cancer. Endemic fluorosis, mainly occurring in western Guizhou, was mostly attributed to the high fluorine in clay that was used as a briquette binder for fine coals, in addition to a small quantity of fluorine from coal. Fluorine in the coal from endemic-fluorosis areas of western Guizhou is within the usual range found in China and the world. Endemic arsenosis in southwestern Guizhou is attributed to indoor combustion of high-As coal. Endemic selenosis in Enshi of Hubei was due to high Se in carbonaceous siliceous rocks and carbonaceous shales. Fine particles of quartz, released into air during coal combustion, are hypothesized as a possible cause for the lung cancer epidemic in Xuanwei, Yunnan, China.Valuable elements, including Ge, Ga, U, REE (rare earth element), Nb, Zr, and Re are concentrated to levels comparable to conventional economic deposits in several coals or coal-bearing strata in China. The Ge deposits at Lincang, Yunnan province and Wulantuga, Inner Mongolia have been exploited and industrially utilized. The enrichment of Ge in the two deposits was caused by hydrothermal fluids associated with adjacent granitoids. The Ga (Al) ore deposit in the Jungar Coalfield, Inner Mongolia, was derived from the neighboring weathered and oxidized bauxite of the Benxi Formation (Pennsylvanian). The Nb(Ta)-Zr(Hf)-REE-Ga deposits in the Late Permian coal-bearing strata of eastern Yunnan and Chongqing of southwestern China were attributed to ashes of the alkali volcanic eruptions. © 2011 Elsevier B.V.


Zhang B.,China University of Mining and Technology | Chen G.Q.,Peking University
Ecological Indicators | Year: 2014

For the greenhouse gas (GHG) emissions in China, little attention has been given to CH4 emissions and related emission mitigation. This paper presents a detailed bottom-up estimation and comparison analysis of China's CH4 and CO2 emissions for the first time. China's CH4 emissions are shown with comparable importance to the CO2 emissions at the national and regional levels. The national total CH4 emission in 2008 amounts to 39 Tg, equivalent to about 1/8, 1/3 and 3/5 of the total CO2 emission by the 100-year global warming potential (GWP) factor, the 20-year GWP factor and the global thermodynamic potential factor, respectively. Increasing CH4 emissions could compromise China's efforts to mitigate its GHG emissions. In contrast to energy-dominated emission pattern for CO2, the major sources of China's CH4 emissions are coal mining, enteric fermentation, rice cultivation and waste management. Meanwhile, there exists a large gap between the eastern coastal regions and the western and central inland regions in the emission magnitude and emission intensity for CH4 and CO2, with different mitigation flexibilities. Reducing CH4 emissions should be integrated into the national and regional policies for GHG emission mitigation. In some central and western regions such as Shanxi, Henan, Sichuan, Guizhou, Qinghai and Tibet, the inclusion of CH4 emission intensity reduction can be more cost-effective than only setting a target for CO2 emission intensity to reduce the regional GHG emission intensity. © 2014 Elsevier Ltd. All rights reserved.


Ding H.,China University of Mining and Technology | Zhao J.,China University of Mining and Technology
International Journal of Modelling, Identification and Control | Year: 2013

To imitate the real hydraulic hoist used in mines and enhance its control performance, a pump controlled motor speed servo (PCMSS) is presented. Mathematic models of PCMSS with and without a position loop are established and their dynamic characteristics are studied by simulation and experiments. Results indicate that PCMSS without a position loop is susceptible to interrupt and uncontrollable only depending on the external motor speed closed-loop, whereas PCMSS with a position loop can achieve high stability and speed precision relying on the internal position closed-loop in the pump and the external speed closed-loop. Therefore, to achieve higher performances for PCMSS, the displacement of a variable delivery pump should be independently adjusted while motor speed is fed back and controlled in closed-loop. Based on this theory, two electrohydraulic servo control schemes are proposed for automation reform of traditional hydraulic hoisters. © 2013 Inderscience Enterprises Ltd.


Xu S.-C.,China University of Mining and Technology | He Z.-X.,Nanjing Forestry University | He Z.-X.,Jiangsu University | Long R.-Y.,China University of Mining and Technology
Applied Energy | Year: 2014

This study analyzes factors that influence carbon emissions due to fossil energy consumption in China to identify key factors for policies promoting carbon emission reductions. Carbon emissions for energy consumption are decomposed into energy structure, energy intensity, industry structure, economic output, and population scale effects. The major driver of carbon emissions is the economic output effect, followed by population scale and energy structure effects. The energy intensity effect is a main inhibitory factor. The factors influencing carbon emissions in China were investigated for different industries, sectors and regions. The results show that carbon emissions mostly arise from industry, while the other sectors generally exhibit good performance in reducing emissions. In industry, the main contributors to carbon emissions are electricity production, petroleum processing and coking, metal smelting and rolling, chemical manufacture, and non-metal mineral products. Regional analysis revealed differences in economic output, energy intensity, and industrial structure among three regions of China. Policy implications in terms of industrial structure and energy consumption are highlighted. © 2014 Elsevier Ltd.


Chen L.,China University of Mining and Technology | Toner J.,University of Oregon
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2013

We study theoretically the smectic-A to -C phase transition in isotropic disordered environments. Surprisingly, we find that, as in the clean smectic-A to -C phase transition, smectic layer fluctuations do not affect the nature of the transition, in spite of the fact that they are much stronger in the presence of the disorder. As a result, we find that the universality class of the transition is that of the "random field XY model" (RFXY). © 2013 American Physical Society.


Niu J.,Beijing Normal University | Bao Y.,Beijing Normal University | Li Y.,Beijing Normal University | Chai Z.,China University of Mining and Technology
Chemosphere | Year: 2013

Electrochemical degradation of pentachlorophenol (PCP) in aqueous solution was investigated over Ti/SnO2-Sb electrodes prepared by sol-gel method. X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical measurements were used to characterize the physicochemical properties of the electrodes. The electrochemical degradation of PCP followed pseudo-first-order kinetics. The main influencing factors, including the types of supporting electrolyte (i.e., NaClO4, Na2SO4, Na2SO3, NaNO3, and NaNO2), initial concentrations of PCP (5-1000mgL-1), pH values (3.0-11.0), and current densities (5-40mAcm-2) were evaluated. The degradation and mineralization ratios of 100mgL-1 of PCP achieved >99.8% and 83.0% after 30min electrolysis with a 10mmolL-1 Na2SO4 at a current density of 10mAcm-2, respectively. The corresponding half-life time (t1/2) was 3.94min. The degradation pathways that were involved in dechlorination, protons generation, and mineralization processes were proposed based on the determination of total organic carbon, chloride, and intermediate products (i.e., low chlorinated phenol and some organic acids). The toxicity of PCP and its intermediates could be reduced effectively by electrolysis. These results showed that electrochemical technique could achieve a significant mineralization rate in a short time (<30min), which provided an efficient way for PCP elimination from wastewater. © 2013 Elsevier Ltd.


Zhang G.,University of Essex | Yang K.,China University of Mining and Technology | Liu P.,China University of Mining and Technology
IEEE Communications Letters | Year: 2012

This letter studies the joint relay selection (RS) and spectrum allocation (SA) problem for the multi-user and multi-relay (MUMR) cellular networks. Regarding the amount of spectrum resource that a relay is willing to contribute for a particular user as the cooperative strategy of the relay, the joint RS and SA problem can be formulated as a cooperative bargaining game. Since there exists a unique Nash bargaining solution (NBS) to the game, a Langrangian relaxation with iterative search approach is proposed to find the NBS. By comparing with the maximal-rate and the max-min based RS and SA schemes, simulation results show that the proposed bargaining game approach achieves a fair and efficient rates distribution among the competitive users in the Pareto optimal sense. © 2012 IEEE.


Zhang G.,China University of Mining and Technology | Yang K.,University of Essex | Liu P.,China University of Mining and Technology | Ding E.,China University of Mining and Technology | Zhong Y.,China University of Mining and Technology
IEEE Transactions on Vehicular Technology | Year: 2012

Resource-exchange-based incentive mechanisms are investigated for both selection cooperation (SC) and selection relaying (SR) networks using the cooperative bargaining game approach. Consider a user node that can act as a source as well as a potential relay for other nodes, and it is selfish to share an own resource with others only if the data rate achieved through cooperative relaying is not lower than that achieved without the cooperation by consuming the same amount of the resource. In the SC scenario, only one relay is allotted to a source. Then, a two-person SC game (SCG) is formulated to address the joint bandwidth and power allocation problem for two cooperative nodes. In the SR scenario, a set of relays is allotted to a source. Hence, we propose a one-to-many SR game (SRG) to address the multinode cooperation case. For both SCG and SRG, specific data frame structures are designed to accommodate both the bandwidth resource (in the form of transmission time) and the energy resource (in the form of transmission power) for a cooperative node. To achieve the system efficiency and per-node fairness objectives simultaneously, the Nash bargaining solution (NBS) method is used to solve both SCG and SRG. The existence and uniqueness of the NBS are proved. Moreover, theoretical analysis and simulations are provided to testify as to the effectiveness of the proposed SCG and SRG for efficient and fair resource allocation in the SC and SR scenarios, respectively. © 1967-2012 IEEE.


Hao Y.-J.,Yanshan University | Srivastava H.M.,University of Victoria | Jafari H.,University of Mazandaran | Yang X.-J.,China University of Mining and Technology
Advances in Mathematical Physics | Year: 2013

The main object of this paper is to investigate the Helmholtz and diffusion equations on the Cantor sets involving local fractional derivative operators. The Cantor-type cylindrical-coordinate method is applied to handle the corresponding local fractional differential equations. Two illustrative examples for the Helmholtz and diffusion equations on the Cantor sets are shown by making use of the Cantorian and Cantor-type cylindrical coordinates. © 2013 Ya-Juan Hao et al.


Lv J.-P.,China University of Mining and Technology | Lv J.-P.,Zhejiang University | Chen Q.-H.,Zhejiang University | Chen Q.-H.,Zhejiang Normal University | Deng Y.,Hefei University of Technology
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2014

Using worm-type quantum Monte Carlo simulations, we investigate bosonic mixtures on a triangular lattice of two species of bosons, which interact via nearest-neighbor intraspecies (V) and on-site interspecies (U) repulsions. For the case of symmetric hopping amplitude (tA/V=tB/V) and U/V=1, we determine a rich ground-state phase diagram that contains double-solid, double-superfluid, supersolid (SS), solid-superfluid (solid-SF), and counterflow supersolid (CSS) states. The SS, solid-SF, and CSS states exhibit spontaneous symmetry breaking among the three sublattices of the triangular lattice and between the two species, which leads to a nonzero crystalline density wave order in each species. We, furthermore, show that the CSS and the SS states are present for tA/V≠tB/V, and the latter even survives up to the tA/V→∞ or tB/V→∞ limit. The effects induced by the variation of U/V and by the imbalance of particle numbers of the two species are also explored. © 2014 American Physical Society.


Chen L.,China University of Mining and Technology | Toner J.,University of Oregon
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2012

We study the smectic-A-smectic-C phase transition in biaxial disordered environments, e.g., fully anisotropic aerogel. We find that both the A and C phases belong to the universality class of the "XY Bragg glass," and therefore have quasi-long-ranged translational smectic order. The phase transition itself belongs to a new universality class, which we study using an ε=7/2-d expansion. We find a stable fixed point, which implies a continuous transition, the critical exponents of which we calculate. © 2012 American Physical Society.


Wang Y.-F.,China University of Mining and Technology | Wang Y.-F.,China Coal Technology and Engineering Co. | Li Y.-Z.,China Coal Technology and Engineering Co.
Meitan Xuebao/Journal of the China Coal Society | Year: 2012

In view of the problem of gas drainage from holes through coal in the low permeability coal seam, a new permeability improvement technology of directional hydraulic penetration by guided groove was put forward. The directional hydraulic fracturing of guided groove hole directed by guided groove and control hole, the coal between guided groove hole and control hole was penetrated, and took coal out by high pressure water, made the hole controlled coal loose stress, and improved the coal permeability effectively. The directional hydraulic mechanism was put forward and analyzed. Permeability improvement technology of directional hydraulic penetration by guided groove was described and studied in detail. The in-situ experimental results show that gas drainage scope rise more than 1 time, the hole flow increases by an average of 3.87 times, boreholes engineering reduce 65%.


Sheng X.,University of Illinois at Urbana - Champaign | Bower C.A.,Semprius | Bonafede S.,Semprius | Wilson J.W.,Semprius | And 10 more authors.
Nature Materials | Year: 2014

Expenses associated with shipping, installation, land, regulatory compliance and on-going maintenance and operations of utility-scale photovoltaics can be significantly reduced by increasing the power conversion efficiency of solar modules through improved materials, device designs and strategies for light management. Single-junction cells have performance constraints defined by their Shockley-Queisser limits. Multi-junction cells can achieve higher efficiencies, but epitaxial and current matching requirements between the single junctions in the devices hinder progress. Mechanical stacking of independent multi-junction cells circumvents these disadvantages. Here we present a fabrication approach for the realization of mechanically assembled multi-junction cells using materials and techniques compatible with large-scale manufacturing. The strategy involves printing-based stacking of microscale solar cells, sol-gel processes for interlayers with advanced optical, electrical and thermal properties, together with unusual packaging techniques, electrical matching networks, and compact ultrahigh-concentration optics. We demonstrate quadruple-junction, four-terminal solar cells with measured efficiencies of 43.9% at concentrations exceeding 1,000 suns, and modules with efficiencies of 36.5%. © 2014 Macmillan Publishers Limited.


Yang H.-Y.,East China Institute of Technology | Yue J.-H.,China University of Mining and Technology
Zhongguo Kuangye Daxue Xuebao/Journal of China University of Mining and Technology | Year: 2013

All-time apparent resistivity calculation method is an important component in theoretical system of underground transient electromagnetic method (TEM). Based on analysis of full-space kernel function, kernel function algorithm (KFA) was put forward to calculate full-space all-time apparent resistivity in this paper, and its calculating effect was verified using theoretical data. Meanwhile, its application effect was compared with translation algorithm, which was used to solve all-time apparent resistivity in half-space TEM. The results indicate that, full-space kernel function is a monotonically increasing function of electric conductivity when sampling instant is later than 10 μs and side length of transmitting loop is longer than 5 m. The equivalent side length and the sampling instant of multi-turn coils used in mine all meet this requirement. All-time apparent resistivity obtained from KFA reaches model's "real" resistivity whether it is in early time, in transition region, or in later time. RMS errors of KFA and Translation algorithm are 6.945 1×10-4 and 1.030 0×10-2 with a 10 Ω·m homogeneous full-space model, which indicates that KFA has a higher accuracy and stability. The interpretation of measured data shows that, KFA can achieve a better application effect, which enriches the theoretical system of full-space TEM and provides a reference for measured data processing in mine.


Jiang M.,CAS Institute of Physics | Lv Q.Z.,China University of Mining and Technology | Sheng Z.M.,Shanghai JiaoTong University | Grobe R.,Illinois State University | Su Q.,Illinois State University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2013

We study the creation of electron-positron pairs induced by two spatially separated electric fields that vary periodically in time. The results are based on large-scale computer simulations of the time-dependent Dirac equation in reduced spatial dimensions. When the separation of the fields is very large, the pair creation is caused by multiphoton transitions and mainly determined by the frequency of the fields. However, for small spatial separations a coherence effect can be observed that can enhance or reduce the particle yield compared to the case of two infinitely separated fields. If the travel time for a created electron or positron between both field locations becomes comparable to the period of the oscillating fields, we observe peaks in the energy spectrum which can be explained in terms of field-induced transient bound states. © 2013 American Physical Society.


Guo S.-D.,China University of Mining and Technology | Guo S.-D.,CAS Institute of Physics | Liu B.-G.,CAS Institute of Physics
Physica B: Condensed Matter | Year: 2013

We investigate the electronic structures of the cubic and tetragonal phases of Sr2MgWO6. Calculated electronic structures show that the two phases are both wide indirect band gap semiconductors. Our phonon calculations indicate that the structural phase transition from cubic to tetragonal phase is because the phonon frequencies of Γ4+ modes become imaginary. Our variable cell-shape relaxation results imply that a symmetry-allowed intermediate trigonal phase could be realized. © 2012 Elsevier B.V. All rights reserved.


Ding S.,China University of Mining and Technology | Ding S.,Beijing University of Posts and Telecommunications | Qi B.,China University of Mining and Technology
Artificial Intelligence Review | Year: 2012

Granular support vector machine (GSVM) is a new learning model based on Granular Computing and Statistical Learning Theory. Compared with the traditional SVM, GSVM improves the generalization ability and learning efficiency to a large extent. This paper mainly reviews the research progress of GSVM. Firstly, it analyzes the basic theory and the algorithm thought of GSVM, then tracking describes the research progress of GSVM including the learning model and specific applications in recent years, finally points out the research and development prospects. © 2011 Springer Science+Business Media B.V.


Zhang Y.,North China University of Water Conservancy and Electric Power | Baleanu D.,Cankaya University | Baleanu D.,Romanian Space Science Institute | Yang X.,China University of Mining and Technology
Entropy | Year: 2014

In this paper, based on fixed entropy, the adiabatic equation of state in fractal flow is discussed. The local fractional wave equation for the velocity potential is also obtained by using the non-differential perturbations for the pressure and density of fractal hydrodynamics. © 2014 by the authors.


Kong S.,China University of Mining and Technology | Cheng Y.,China University of Mining and Technology | Ren T.,University of Wollongong | Liu H.,China University of Mining and Technology
Applied Energy | Year: 2014

As coal resources become exhausted in shallow mines, mining operations will inevitably progress from shallow depth to deep and gassy seams due to increased demands for more coal products. However, during the extraction process of deeper and gassier coal seams, new challenges to current gas control methods have emerged, these include the conflict between the coal mine safety and the economic benefits, the difficulties in reservoirs improvement, as well as the imbalance between pre-gas drainage, roadway development and coal mining. To solve these problems, a sequential approach is introduced in this paper. Three fundamental principles are proposed: the mining-induced stress relief effect of the first-mined coalbed should be sufficient to improve the permeability of the others; the coal resource of the first-mined seams must be abundant to guarantee the economic benefits; the arrangement of the vertical wells must fit the underground mining panel. Tunlan coal mine is taken as a typical example to demonstrate the effectiveness of this approach. The approach of integrating surface coalbed methane (CBM) exploitation with underground gas control technologies brings three major benefits: the improvement of underground coal mining safety, the implementation of CBM extraction, and the reduction of greenhouse gas emissions. This practice could be used as a valuable example for other coal mines having similar geological conditions. © 2014 Elsevier Ltd.


Ding S.,China University of Mining and Technology | Ding S.,CAS Institute of Computing Technology | Hua X.,China University of Mining and Technology | Hua X.,Yancheng Institute of Technology
Neurocomputing | Year: 2014

During the last few years, multiple surface classification (MSC) algorithms, such as projection twin support vector machine (PTSVM), and least squares PTSVM (LSPTSVM), have attracted much attention. However, there are not any modifications of them that have been presented to handle nonlinear classification. This motivates the rush towards new classifiers. In this paper, we formulate a nonlinear version of the recently proposed LSPTSVM for binary nonlinear classification by introducing nonlinear kernel into LSPTSVM. This formulation leads to a novel nonlinear algorithm, called nonlinear LSPTSVM (NLSPTSVM). Additionally, in order to promote its generalization capability, we also extend the recursive leaning method, used for further boosting the performance of PTSVM and LSPTSVM, to the nonlinear case. Experimental results on synthetic datasets, UCI datasets and NDC datasets show that NLSPTSVM has better classification capability. © 2013 Elsevier B.V.


Patent
China University of Mining, Technology and Dongnan Elevator Co. | Date: 2013-03-25

Disclosed is a fall prevention brake buffering system for high-speed mine lift, including brake ropes (2) fixed on two sides of a car (5). One end of the brake rope (2) is fixed on the top part of a vertical well (6), and the other end is fixed on the bottom part of the vertical well (6). A linkage mechanism (11) is arranged at the bottom of the car (5). A buffer (1) is arranged at the top of the brake rope (2), and a tension connector (4) is arranged at the bottom of the brake rope (2). A brake rope safety tong (3) fixed on the brake rope (2) and connected with the linkage mechanism (11) is arranged at the bottom of the car (5). The buffer (1) includes an inverted brake rope gradual safety tong (8) with a buffering rope (9) provided therein and connected with the brake rope (2). A buffering rope clip (10) is arranged on the buffering rope (9). The system is convenient to install, and the buffering force of the brake rope is constant and adjustable. The system realizes reliable fall prevention brake function, greatly improves safety performance during high-speed operation of a lift with non-rigid rails, and increases safety performance during high-speed operation of a mine lift.


Patent
China University of Mining, Technology and Dongnan Elevator Co. | Date: 2013-03-25

A mining elevator carrying platform and carrying method, the platform comprises a power system (1) and a four-rod carrying device (5), a rotating rod (3) connected with the power system (1) is set on the carrying device (5); the power system (1) comprises a flameproof motor (1-1), a upper-limited switch (1-2), a down-limited switch (1-5) and a main pulley (1-6), the flameproof motor (1-1) is connected with the main pulley (1-6) through a main steel cable (1-4), a baffle (1-3) is set on the main steel cable (1-4), a double cable channel is set on the main pulley (1-6), and the main pulley (1-6) is connected with a sub-pulley (1-8) by a sub-steel cable (1-7), a sliding plate (1-9) is set on the sub-steel cable (1-7), and a sliding rod (1-10) is set on the sliding plate (1-9). The main pulley (1-6) is driven to rotate by the flameproof motor (1-1) through the main steel cable (1-4), thus the sub-pulley (1-8) is driven to rotate. The sliding rod (1-10) moves in a strip-opening sliding slot in the rotating rod (3) by the sliding plate (1-9) moving up and down, then the rotating rod (3) and a carrying plate (5-1) are driven to move circumferentially. A rocker (5-3) is rotated around a supporting bracket (5-4) driven by a connecting rod (5-2), thus a credible carrying platform in multi-plane is realized. The platform is simple in structure, controlled accurately, convenient to be fixed and maintained, operated stably and reliably, and has the self-locking function.


Patent
Dongnan Elevator Co., China University of Mining and Technology | Date: 2011-08-25

A mining elevator traction cable connecting apparatus and a measuring method therefor, for use in a mining elevator serving a deep-mine. The apparatus includes an industrial personal computer (IPC), a signal collector connected to the IPC, multiple symmetrically arranged cable rings for use in connecting to one end of a traction cable, and a traction cable tension adjusting apparatus connected to the multiple of cable rings. Arranged within the traction cable tension adjusting apparatus are a plurality of hydraulic cylinders, and a plurality of draw wire displacement sensors for use in monitoring the relative displacement between each hydraulic cylinder plunger and a corresponding hydraulic cylinder body. The draw wire displacement sensors and an oil pressure sensor connected to a hydraulic pipeline are connected to the IPC via the signal collector, forming a traction cable tension and degree of adjustment measuring system.


Patent
Dongnan Elevator Co., China University of Mining and Technology | Date: 2014-03-26

An elevator anti-fall buffer based on flexible guidance. The anti-fall buffer is used for connecting and fixing an end part of a braking steel rope of an elevator. The anti-fall buffer has an upper support plate and a lower support plate, wherein a pulley set is provided on the upper support plate and the lower support plate, and a hydraulic damping buffer is provided at two sides of the pulley set. The anti-fall buffer uses the energy consumption principle of a hydraulic damping hole, and while protecting the braking steel rope from the force of impact created thereon by the elevator, prevents the force of impact from a spring on the elevator post-braking, improving the safety and reliability of elevator braking, thereby improving safety of an elevator, while also using a pulley set can increase the braking distance of the braking steel rope, thereby lengthening life of the steel rope.


Patent
Dongnan Elevator Co., China University of Mining and Technology | Date: 2011-08-25

Disclosed are an apparatus and a method for automatically adjusting the tension on a mining elevator flexible guide rail. The apparatus comprises an automatic tightening apparatus (1) at the opening of the well, and a fixing apparatus (2) on the bottom of the well, respectively connected to two ends of the steel cable (3). The automatic tightening apparatus (1) at the opening of the well is connected to a hydraulic system (5) and to a tension measuring system (4). The automatic tightening apparatus (1) at the opening of the well comprises a lower retainer seat (1-14) arranged on an upper bearer beam (1-1), a tightening oil cylinder body (1-2) and a plunger thereof (1-3), a pin shaft retainer (1-11), a support frame (1-6), a fall-proof holder (1-13), a pin shaft holder (1-5), a fall-proof cable retainer (1-12), a tightening fixed cable retainer (1-10), two guide columns (1-7) and guide grooves thereof, an upper retainer seat (1-9), and a cable orientation-adjusting cable retainer (1-8). The fixing apparatus (2) on the bottom of the well comprises a fixing plate (2-3), and a fixed cable retainer (2-5). The apparatus and the method allow the flexible guide rail to be structurally simple, convenient to process, reliable in performance, and easy to install and to maintain. The apparatus and the method allow restriction of vertical orientation and horizontal deflection, and are capable of real-time detection and automatic adjustment of the tension in the flexible guide rail of the elevator.


Mao S.,Shanghai JiaoTong University | Zhou J.,China University of Mining and Technology
Dianli Zidonghua Shebei/Electric Power Automation Equipment | Year: 2012

According to the topology of four-leg SAPF (Shunt Active Power Filter), a compound control strategy is put forward, which combines the generalized integrators with the abc -coordinates-based 3-D SVPWM (3-Dimensional Space Vector Pulse Width Modulation). The generalized integrator compensates the specified harmonic without static error while the 3-D SVPWM has higher DC voltage utilization ratio, better DC voltage stability and easier digital realization. The simulation model of four-leg SAPF is built and analyzed, and results show that it compensates the three-phase network harmonic currents, negative-sequence fundamental current, zero-sequence fundamental current and neutral current effectually and order-specifically, with both faster dynamic response and smaller static error, which verifies its validity and feasibility.


Song Z.,China University of Mining and Technology | Song Z.,German Aerospace Center | Kuenzer C.,German Aerospace Center
International Journal of Coal Geology | Year: 2014

Coal fires pose great threats to valuable energy resources, the environment, and human health and safety. They occur in numerous countries in the world. It is well-known that China, the largest coal producer and user globally, is one of the countries that have badly suffered from coal fires. Thus, over the course of the last decade, a lot of local research studies on coal fires in China have been published in international and Chinese scientific journals. The goal of this paper is to set the scene on past and current coal fire research in China. In this review we explore multidisciplinary investigations undertaken during the last decade associated with coal fires in China including fire detection, modeling, the assessment of environmental and human health impacts as well as fire-fighting engineering. We outline a systematic framework of research on coal fires and address inter-relations of sub-topics within this systematic framework. Additionally, the scientific and technical studies and their advantages, shortcomings and challenges for coal mine administrations are discussed. It is hoped that this comprehensive overview provides scientific guidance for management and coordination of coal fire projects. © 2014 Elsevier B.V. All rights reserved.


Ding S.,China University of Mining and Technology | Li H.,China University of Mining and Technology | Su C.,China University of Mining and Technology | Yu J.,China University of Mining and Technology | Jin F.,Shandong University of Science and Technology
Artificial Intelligence Review | Year: 2013

This paper reviews the use of evolutionary algorithms (EAs) to optimize artificial neural networks (ANNs). First, we briefly introduce the basic principles of artificial neural networks and evolutionary algorithms and, by analyzing the advantages and disadvantages of EAs and ANNs, explain the advantages of using EAs to optimize ANNs. We then provide a brief survey on the basic theories and algorithms for optimizing the weights, optimizing the network architecture and optimizing the learning rules, and discuss recent research from these three aspects. Finally, we speculate on new trends in the development of this area. © 2011 Springer Science+Business Media B.V.


Jiang S.,Nanjing Southeast University | Zheng Y.,Nanjing Southeast University | Zhu H.,China University of Mining and Technology
Journal of Tribology | Year: 2010

A general contact stiffness model is proposed in this paper to study the contacts between rough surfaces of machined plane joints. The proposed model uses fractal geometry for surface topography description, elastic-plastic deformation of contacting asperities, and size-dependent contact stiffness of micro contacts, where the contact stiffness is derived from Hertz contact theory. Three cast iron specimens are produced from different machining methods (milling, grinding, and scraping), and their rough surface profiles are extracted. The structure function method was used to calculate each profile's fractal dimension and scale coefficient. Both theoretical analysis and experimental results of contact stiffness are obtained for these specimens under different contact loads. The comparison between the theoretical contact stiffness and the experimental results at the interface indicates that the present fractal model for the contact stiffness is appropriate and the theoretical contact stiffness is consistent with the experimental data. © 2010 by ASME.


Heng L.,CAS Beijing National Laboratory for Molecular | Wang X.,China University of Mining and Technology | Yang N.,CAS Beijing National Laboratory for Molecular | Zhai J.,CAS Beijing National Laboratory for Molecular | And 3 more authors.
Advanced Functional Materials | Year: 2010

In this paper, a new type of flexible working electrode, TiO 2/Cul/Cu, is reported, in which the p-n junction of TiO 2-Cul is introduced into dyesensitized solar cells (DSSCs) for the first time. The devices give a high conversion efficiency of up to 4.73% under 1 sun illumination. The excellent performance is ascribed to the existence of the p-n junction, which forms a single directional pathway for electron transport which benefits the charge separation, and improves the efficiency of the flexible solar cells as a result. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA.


Zhao Y.,Jilin University | Baleanu D.,King Abdulaziz University | Baleanu D.,Cankaya University | Baleanu D.,Romanian Space Science Institute | And 3 more authors.
Advances in High Energy Physics | Year: 2013

Maxwell's equations on Cantor sets are derived from the local fractional vector calculus. It is shown that Maxwell's equations on Cantor sets in a fractal bounded domain give efficiency and accuracy for describing the fractal electric and magnetic fields. Local fractional differential forms of Maxwell's equations on Cantor sets in the Cantorian and Cantor-type cylindrical coordinates are obtained. Maxwell's equations on Cantor set with local fractional operators are the first step towards a unified theory of Maxwell's equations for the dynamics of cold dark matter. © 2013 Yang Zhao et al.


Liu Z.,China University of Mining and Technology | Liu Z.,Nanjing Southeast University | Zhang Y.,Nanjing Southeast University | Jiang Q.,Nanjing Southeast University
Construction and Building Materials | Year: 2014

The electrical resistivity changes with time of cement pastes with water to cement ratio of 0.23, 0.35 and 0.53 were in situ continuously monitored by using a non-contact resistivity apparatus. To aid in understanding the evolution of effective resistivity, a hydration model CEMHYD3D was then utilized to simulate the early age formation of microstructure. Based on the effective media theory, the relationship between the change of relative resistivity and the evolution of total porosity, tortuosity factor and constrictivity is established. The results show that a lower water to cement ratio shows a smaller porosity and constrictivity as well as a higher tortuosity factor. Moreover, according to the experimental and simulated results, it is found that the evolution of resistivity is not only controlled by capillary pores but also C-S-H phases. Before arriving fully de-percolation time of capillary pores, the reduction of pores connectivity shows a higher influence on the paste resistivity than the decrease of capillary porosity. After that, the resistivity change of cement paste is mainly determined by the volume fraction of C-S-H. © 2013 Elsevier Ltd. All rights reserved.


Yang Y.,Nanjing Southeast University | Shen X.,Nanjing Southeast University | Shen X.,China University of Mining and Technology | Zhao P.,Nanjing Southeast University | And 2 more authors.
Optics Express | Year: 2015

It has been demonstrated that an ultrathin uniformly corrugated metallic strip is a good plasmonic waveguide in microwave and terahertz frequencies to propagate spoof surface plasmon polaritons (SPPs) with well confinement and small loss (Shen et al., PNAS 110, 40-45, 2013). Here, we propose a simple method to trap SPP waves on the ultrathin corrugated metallic strips in broad band in the microwave frequencies. By properly designing non-uniform corrugations with gradient-depth grooves, we show that the SPP waves are slowed down gradually and then reflected at predesigned positions along the ultrathin metallic strip when the frequency varies. We design and fabricate the ultrathin gradient-corrugation metallic strip on a thin dielectric film. Both numerical simulation and measurement results validate the efficient trapping of SPP waves in broadband from 9 to 14 GHz. This proposal is a promising candidate for slow-wave devices in both microwave and terahertz regimes. © 2015 OSA.


Guo Z.-P.,Shandong University of Science and Technology | Huang W.-P.,China University of Mining and Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2011

Using mine pressure theory, rock plate theory and method of numerical simulation, the filling parameter of gangue strip-filling working face in a coal mine was optimized, and the scheme filling 60 m and leaving 25 m was confirmed. According to numerical simulation, it was obtained that the fillings plastic zone proportional coefficient and the fillings width show power exponential function of concave shape. Then the fillings were regarded as elastic-plastic body to establish the mechanics model which included rectangle thin rock plate and fillings. Using plate mechanics and material mechanics theory, the calculation formula of the largest displacement of the roof was obtained, and the largest displacement of main roof plate was accounted to 8.73 cm, which shows that the result anastomoses with numerical simulation.


Ruo-Qiang F.,Nanjing Southeast University | Ruo-Qiang F.,China University of Mining and Technology | Bin Y.,China United Engineering Corporation | Jihong Y.,Nanjing Southeast University
Journal of Constructional Steel Research | Year: 2013

A cable-braced grid shell is a new type of single-layer latticed shell suitable for glass roofs. Compared with traditional single-layer latticed shells, this new type of shell has a unique mesh shape, mesh form and surface shape. The lamella cylinder cable-braced grid shell is the single-layer latticed structure, and therefore, stability is a key design factor. These shells are also sensitive to initial imperfections, and thus, the influence of initial imperfections on stability should be considered. Therefore, in this paper, a lamella cylinder cable-braced grid shell with imperfections is used to develop formulas to describe the buckling load based on the continuum analogy. The major contributions of this paper include the formula for the linear buckling load of a lamella cylinder cable-braced grid shell with imperfections, which is deduced based on the continuum analogy. Then, the equivalent rigidity for a lamella mesh is determined. Last, the formula for the linear buckling load is verified by numerical examples, the errors are analyzed, and a corresponding correction factor is provided. © 2013 Elsevier Ltd.


Shen X.,Nanjing Southeast University | Shen X.,China University of Mining and Technology | Cui T.J.,Nanjing Southeast University | Zhao J.,Nanjing University | And 3 more authors.
Optics Express | Year: 2011

We report the design, fabrication, and measurement of a microwave triple-band absorber. The compact single unit cell consists of three nested electric closed-ring resonators and a metallic ground plane separated by a dielectric layer. Simulation and experimental results show that the absorber has three distinctive absorption peaks at frequencies 4.06GHz, 6.73GHz, and 9.22GHz with the absorption rates of 0.99, 0.93, and 0.95, respectively. The absorber is valid to a wide range of incident angles for both transverse electric (TE) and transverse magnetic (TM) polarizations. The triple-band absorber is a promising candidate as absorbing elements in scientific and technical applications because of its multiband absorption, polarization insensitivity, and wide-angle response. © 2011 Optical Society of America.


Shen X.,Nanjing Southeast University | Shen X.,China University of Mining and Technology | Jun Cui T.,Nanjing Southeast University
Applied Physics Letters | Year: 2013

We propose a planar plasmonic metamaterial on thin corrugated metal films in microwave and terahertz frequencies. From theoretical simulation and experiment, we show that spoof surface plasmon polaritons (SPPs) can propagate along a thin metal film by corrugating its edge with periodic array of grooves. We demonstrate that such a planar plasmonic metamaterial can sustain highly localized SPPs along two orthogonal directions. We have designed and simulated a planar ring resonator in the terahertz frequency, and made experiment in the microwave frequency, both of which exhibit excellent performance. The proposed planar plasmonic metamaterials can play important roles in integrated plasmonic circuits and systems. © 2013 AIP Publishing LLC.


Xia T.,China University of Mining and Technology | Xia T.,CAS Wuhan Institute of Rock and Soil Mechanics | Zhou F.,China University of Mining and Technology | Liu J.,University of Western Australia | And 2 more authors.
Fuel | Year: 2014

The spontaneous combustion of underground coal seams involves complex interactions between geomechanical effects, oxygen transport and flow, and energy transport in the porous coal media. Prior studies normally ignore the thermo-mechanical effects such as gas and coal expansion due to the self-heating of coal, and have not implemented these complex interactions fully into their simulations. In this study, a fully coupled model of coal mechanical deformation, gas flow and transport, and heat transport is developed and their complex interactions are defined through a suite of coal property models and equation-of-states. These include (1) coal porosity model; (2) coal permeability model; (3) gas equation-of-state; and (4) self-heating model. Applying the model to quantitatively predict the time and locations of spontaneous combustion of underground gob-side entry in the Dongtan coal mine, the results are in good agreement with the in situ measurements. Besides, a significant self-accelerating-heating effect induced by the gas thermal expansion and subsequent gas pressure gradient increase is found in the self-heating process of coal through the comparison results from our model with other models. Furthermore, the self-heating susceptibilities of gob-side entry associated with extrinsic and intrinsic factors, incorporating coal permeability, pressure difference, oxygen-consumption rate, and reaction heat of coal oxidation, are gained insight using the verified model, which suggests the self-heating rate and gas velocity are positively correlated with above factors showing "S-type" upward trends, whereas the oxygen concentration has an "S-type" downward trend. The simulated results can provide some suggestions as to how to control the variables or parameters to retard or suppress the spontaneous combustion of porous coal media. © 2014 Elsevier Ltd. All rights reserved.


Xia T.,China University of Mining and Technology | Xia T.,CAS Wuhan Institute of Rock and Soil Mechanics | Zhou F.,China University of Mining and Technology | Liu J.,University of Western Australia | Gao F.,China University of Mining and Technology
Fuel | Year: 2014

Coal seam degasification through underground drilling and its efficiency are directly related to the safety of underground coal mining. The major problem of underground coal seam gas drainage is the rapid decay of gas concentration, which may lead to a low utilization ratio and many hazards, such as environmental pollution, spontaneous combustion of coal, gas combustion and gas explosion. Although coal-gas interactions have been comprehensively investigated, fewer studies consider the low-quality phenomenon (low gas flow and concentration) in the process of gas extraction due to the air leakage of the borehole. In this study, a fully coupled coal deformation and compositional flow model, which represents the important non-linear responses of the gas-drained quality due to the effective stress changes, was implemented into a finite element (FE) model to demonstrate the superiority and reliability of the model through a comparison with another theoretical models and a historical data matching. Subsequently, the susceptibilities of gas-drained quality associated with the intrinsic and extrinsic factors, incorporating the gas sorption, the porosity-fracture characteristics of coal, the sealing depth and the leakage flux, are quantified through a series of simulations. The simulation results revealed that (1) increasing/decreasing the CH4 Langmuir volume/pressure sorption parameter can improve the gas-drained quality, and (2) the leakage fracture characteristics around the borehole are the main factors affecting the gas-drained quality, and thus, increasing the coal permeability or extending sealing depth does not necessarily improve the gas-drained quality under the condition of serious leakage. This FE model and its simulation results can improve the understanding of the coal-gas interactions of underground gas drainage, providing a scientific basis for the evaluation of the gas-drained quality, the design and optimization of drainage systems, etc. © 2014 Elsevier Ltd. All rights reserved.


Lang L.,China University of Mining and Technology | Fu-bao Z.,China University of Mining and Technology | Fu-bao Z.,State Key Laboratory of Coal Resources and Mine Safety
International Journal of Coal Geology | Year: 2010

The traditional identification of spontaneous combustion hazard of coal in China is unilateral and inaccurate, which is singly attributed to the properties of coal. Based on current research findings on coal fires, we've reconsidered the influential factors that lead to the spontaneous combustion of coal seams, and have ultimately built a comprehensive system for evaluating the hazard of spontaneous combustion. Applying holistic scoring method and Analytic Hierarchy Process, we integrated all of the factors into a quantitative model, and classified the ratings into five levels. Additionally, a Visual Basic 6.0 based application program has been developed to assist the evaluation, as well as three domestic colliery cases with varying fire hazards have been tested. Through practical application, the hazard evaluations have proved to be objective and valid, so the system is applicable to Chinese coal mines. © 2010 Elsevier B.V.


Shen X.,Nanjing Southeast University | Shen X.,China University of Mining and Technology | Cui T.J.,Nanjing Southeast University
Journal of Optics (United Kingdom) | Year: 2012

We demonstrate an optically implemented absorption modulation and redshift switch of metamaterial absorber at terahertz frequencies. Hybrid metal-semiconductor split ring resonators (SRRs) form the active structure, which can be tuned by applying an external pump power. This enables effective controls of the absorption strength and absorption peak frequency. As a function of incident pump power, the conductivity of silicon pads filled in the gap of SRRs is tuned efficiently, resulting in the modulation of absorption magnitude with a modulation depth of 60.5%, and a broadband switch of absorption peak frequencies varying from 1.11 to 0.87THz. Multiple-reflection interference theory is used to analyze the reflection spectrum quantitatively under various silicon conductivities, and the results are in good agreement with full-wave simulations. The optical-tuned absorber demonstrates the viability to incorporate metamaterials to mature semiconductor technologies and has potential applications as an active terahertz modulator and switch. © 2012 IOP Publishing Ltd.


Chen P.,China Agricultural University | Li J.,China Agricultural University | Li Q.X.,University of Hawaii at Manoa | Wang Y.,Chinese Academy of Agricultural Sciences | And 3 more authors.
Bioresource Technology | Year: 2012

Rhodococcus sp. CPZ24 was isolated from swine wastewater and identified. Batch (0.25L flask) experiments of nitrogen removal under aerobic growth conditions showed complete removal of 50mgL -1 ammonium nitrogen within 20h, while nitrate nitrogen removal reached 67%. A bioreactor (50L) was used to further assess the heterotrophic nitrification and aerobic denitrification abilities of Rhodococcus sp. CPZ24. The results showed that 85% of the ammonium nitrogen (100mgL -1) was transformed to nitrification products (NO3--N and NO2--N) (13%), intracellular nitrogen (24%), and gaseous denitrification products (48%) within 25h. The ammonium nitrogen removal rate was 3.4mg L -1h -1. The results indicate that the strain CPZ24 carries out simultaneous nitrification and denitrification, demonstrating a potential use of the strain for wastewater treatment. © 2012 Elsevier Ltd.


Shen Y.,Tokyo Institute of Technology | Zhao P.,Nanjing Southeast University | Zhao P.,China University of Mining and Technology | Shao Q.,University of Tokyo | And 2 more authors.
Applied Energy | Year: 2015

A catalytic gasification technology has been proposed for tar in situ conversion using the rice husk char (RHC) or rice husk ash (RHA) supported nickel-iron catalysts. Biomass tar could be converted effectively by co-pyrolysis with the RHC/RHA supported nickel-iron catalysts at 800°C, simplifying the follow-up tar removal process. Under the optimized conditions, the tar conversion efficiency could reach about 92.3% by the RHC Ni-Fe, which exhibited more advantages of easy preparation and energy-saving. In addition, the tar conversion efficiency could reach about 93% by the RHA Ni. Significantly, partial metal oxides (e.g., NiO, Fe2O3) in the carbon matrix of RHC could be in-situ carbothermally reduced into the metallic state (e.g., Ni0) by reducing gases (e.g., CO) or carbon atom, thereby enhancing the catalytic performance of tar conversion. Furthermore, mixing with other solid particles such as sand and RHA Ni, can also improve biomass (e.g., RH) fluidization behavior by optimizing the operation parameters (e.g., particle size, mass fraction) in the mode of fluidized bed gasifier (FBG). After the solid-solid mixing simulation, the RH mass fraction of 0.5 and the particle diameter of 0.5mm can be employed in the binary mixture of RH and RHA. © 2014 Elsevier Ltd.


Shen X.,Nanjing Southeast University | Shen X.,China University of Mining and Technology | Cui T.J.,Nanjing Southeast University
Laser and Photonics Reviews | Year: 2014

The multipolar spoof localized surface plasmons (LSPs) on a planar textured metallic disk are proposed and experimentally demonstrated at microwave frequencies. Based on ultrathin metal film printed on a thin dielectric substrate, the designed plasmonic metamaterial clearly shows multipolar plasmonic resonances, including the dipole, quadrupole, hexapole, octopole, decapole, dodecapole, and quattuordecpole modes. Both numerical simulations and experiments are in good agreement. It is shown that the spoof LSP resonances are sensitive to the disk's geometry and local dielectric environments. Hence, the ultrathin textured metallic disk may be used as plasmonic sensors and find potential applications in the microwave and terahertz frequencies. © 2013 by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Zhang K.,China University of Mining and Technology | Zhou H.,CAS Wuhan Institute of Rock and Soil Mechanics | Shao J.,Lille University of Science and Technology
Rock Mechanics and Rock Engineering | Year: 2013

This paper presents a new constitutive model for the description of elastoplastic behaviour of a porous rock. In the first section, a brief summary of the experimental investigations is presented. The data obtained show that an important coupling exists between elastic and plastic deformation, and that the confining pressure has a great influence on the yielding process of the rock. In the second section, firstly, a plastic internal variable is defined, which is able to record the influence of the stress state on the progressive yielding process. Then, based on the plastic internal variable, the respective evolutions of the subsequent yield surface, dilatancy angle and elastic parameters are studied, and the applicability of the generalized orthogonal flow rule which connects the irreversible strain increment and the yield function are analyzed. The results show that the generalized orthogonal flow rule is not suitable for the porous rock during plastic deformation. Then, based on the experimental evidence, a general formulation of the model is presented. In the third section, simulations of the conventional triaxial compression tests are performed, and the results show that the proposed model is indeed capable of capturing the main features of the mechanical behaviour of the rock. Finally, the model is extended to simulate unloading confining pressure tests, and for which it gives reasonable results. © 2013 Springer-Verlag Wien.


Chen Z.-Y.,National University of Defense Technology | Cattani C.,University of Salerno | Zhong W.-P.,China University of Mining and Technology
Advances in Mathematical Physics | Year: 2014

From the signal processing point of view, the nondifferentiable data defined on the Cantor sets are investigated in this paper. The local fractional Fourier series is used to process the signals, which are the local fractional continuous functions. Our results can be observed as significant extensions of the previously known results for the Fourier series in the framework of the local fractional calculus. Some examples are given to illustrate the efficiency and implementation of the present method. © 2014 Zhi-Yong Chen et al.


He Q.,China University of Mining and Technology | Wan K.,China University of Mining and Technology | Hoadley A.,Monash University | Yeasmin H.,Monash University | Miao Z.,China University of Mining and Technology
Fuel | Year: 2015

Thermal degradation of Shengli lignite was studied by thermogravimetry coupled with gas chromatography-mass spectrometry (TG-GC-MS) for a temperature range from room temperature to 1200°C at a heating rate of 5°C/min. The volatile products released from the lignite gradually with the programmed temperature. The main reaction of pyrolysis took place between 350°C and 800°C. Seven sub-curves were used to fit the DTG curve to analyze the breakage of different bonds. More than 100 different substances were identified at different temperatures from the GC-MS results. Alkanes and benzene series were the major constituents of the released volatile products along with alcohol, naphthalene, benzofuran, indane, indole, biphenyl, etc. Most of the aliphatic compounds were released around 430°C with chain lengths up to C21, with the majority being between C1 and C5. Aromatic hydrocarbons were also released mostly at around 430°C. The number of substituents in a single aromatic compound was found between 0 and 4. The length of the substituent was C1-C6 (sometimes heteroatom instead) and C1 accounted for the most. Generally, TG-GC-MS results presented the mass loss and released gas information with the programmed temperature to bring a better understanding of the structure of the lignite and the pyrolysis process. © 2015 Published by Elsevier Ltd.


Zhao P.,China University of Mining and Technology | Zhao P.,Nanjing Southeast University | Zhao P.,Tokyo Institute of Technology | Shen Y.,Tokyo Institute of Technology | And 3 more authors.
Applied Energy | Year: 2014

Our society currently faces three challenges, including resource depletion, waste accumulation and environmental degradation, leading to rapidly escalating raw material costs and increasingly expensive and restrictive waste disposal legislation. This work aims to produce clean solid biofuel from high moisture content waste biomass (bio-waste) with high nitrogen (N)/chlorine (Cl) content by mild hydrothermal (HT) conversion processes. The newest results are summarized and discussed in terms of the mechanical dewatering and upgrading, dechlorination, denitrification and coalification resulting from the HT pretreatment. Moreover, both the mono-combustion and co-combustion characteristics of the solid fuel are reviewed by concentrating on the pollutants emission control, especially the NO emission properties. In addition, the feasibility of this HT solid biofuel production process is also discussed in terms of "Energy Balance and economic viability". As an alternative to dry combustion/dry pyrolysis/co-combustion, the HT process, combining the dehydration and decarboxylation of a biomass to raise its carbon content aiming to achieve a higher calorific value, opens up the field of potential feedstock for lignite-like solid biofuel production from a wide range of nontraditional renewable and plentiful wet agricultural residues, sludge and municipal wastes. It would contribute to a wider application of HT pretreatment bio-wastes for safe disposal and energy recycling. © 2014 Elsevier Ltd.


Duan Y.,China University of Mining and Technology | Qin L.,China University of Mining and Technology | Shi L.,China University of Mining and Technology | Tang G.,China University of Mining and Technology | Shi H.,Beijing Computational Science Research Center
Applied Physics Letters | Year: 2012

Structural transformation and the variation in the band gap of (0001) AlN and GaN films as a function of equibiaxial in-plane strain are studied using the HSE06 range-separated hybrid functional. Although AlN and GaN under strain share the same structural transition from wurtzite to a graphitelike phase, their electronic properties are significantly different. Both wurtzite and graphitelike AlN under strain can display either direct or indirect band structures, whereas the band gap of wurtzite GaN is always direct and graphitelike GaN always indirect. Furthermore, it is more difficult for AlN than GaN to obtain the graphitelike semi-metallic phase. Our results for GaN support the conclusions obtained from standard density functional theory [Dong, Appl. Phys. Lett. 96, 202106 (2010)] © 2012 American Institute of Physics.


Li Y.,Taiyuan University of Technology | Meng Q.,Taiyuan University of Technology | Deng Y.,Beihang University | Zhou H.,China University of Mining and Technology | And 3 more authors.
Applied Physics Letters | Year: 2012

We synthesized the solid solutions CuGa 1-xIn xTe 2 (x 0-1.0) by isoelectronic substitution of element In (Ga) for Ga(In) in the CuMTe 2 (M Ga, In) lattices and examined their thermoelectric properties. The structure upon substitution provides much high Seebeck coefficient (α), relatively low thermal (κ), and electrical conductivity (σ). AT 701 K, the α, σ, and κ are 283.15 V K -1, 1.15 × 10 4 Ω -1 m -1, and 0.71 W m -1 K -1, respectively, for CuGa 0.36In 0.64Te 2, which give the figure of merit (ZT) of 0.91, about two times those of the mother compounds CuGaTe 2 and CuInTe 2. This material holds great application perspectives at intermediate temperatures. © 2012 American Institute of Physics.


Zhang X.,Tsinghua University | Liang P.,Tsinghua University | Shi J.,Tsinghua University | Shi J.,China University of Mining and Technology | And 2 more authors.
Bioresource Technology | Year: 2013

A shorter start-up time and highly negative anode potentials are needed to improve single-chamber air-cathode microbial fuel cells (MFCs). Using a glass fiber separator reduced the start-up time from 10. d to 8. d at 20 °C, and from 4. d to 2. d at 30 °C, and enhanced coulombic efficiency (CE) from <60% to 89% (20 °C) and 87% (30 °C). Separators also reduced anode potentials by 20-190. mV, charge transfer resistances by 76% (20 °C) and 19% (30 °C), and increased CV peak currents by 24% (20 °C) and 8% (30 °C) and the potential range for redox activity (-0.55 to 0.10. mV vs. -0.49 to -0.24. mV at 20 °C). Using a glass fiber separator in an air-cathode MFC, combined with inoculation at a mesophilic temperature, are excellent strategies to shorten start-up time and to enhance anode performance and CE. © 2012 Elsevier Ltd.


Guo X.Q.,China University of Mining and Technology | Guo X.Q.,McMaster University | Wu W.,University of Tennessee at Knoxville | Wu P.D.,McMaster University | And 3 more authors.
Scripta Materialia | Year: 2013

We experimentally and numerically study the large-strain free-end torsion of a rolled magnesium alloy. It is found that a torsion sample with its axial direction parallel to the normal direction elongates axially, while a sample with its axial direction along the rolling direction contracts axially. It is shown that this Swift effect, i.e., the second-order axial effect under free-end torsion, is mainly due to extension twinning. © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.


Duan Y.,China University of Mining and Technology | Tang G.,China University of Mining and Technology | Chen C.,Tsinghua University | Lu T.,Xi'an Jiaotong University | Wu Z.,Colorado School of Mines
Physical Review B - Condensed Matter and Materials Physics | Year: 2012

The pressure dependence of ferroelectricity and piezoelectricity of a tetragonal BaTiO 3/PbTiO 3 (BPT) short-period superlattice is investigated using first-principles calculations. Our results suggest that, as the applied pressure increases, the BPT superlattice first becomes paraelectric at low pressures and then transfers to another ferroelectric phase at much higher pressures. Furthermore, a large enhancement of piezoelectricity close to the phase-transition regions is predicted, similar to that previously predicted in PbTiO 3. Comparing the BPT superlattice with bulk BaTiO 3 and PbTiO 3, we find that the BPT superlattice behaves very similarly to bulk BaTiO 3 under high pressures for the first transition, while it has much lower transition pressure and zero-pressure spontaneous polarization than those for PbTiO 3, although BPT has an equal number of BaTiO 3 and PbTiO 3 layers. However, for the second transition, BPT has a transition pressure close to the average of those for BaTiO 3 and PbTiO 3, and all three materials have similar pressure-induced polarization. Furthermore, our calculations indicate that the colossal enhancement in piezoelectricity is strongly correlated to phase transition when large atomic displacements can be generated by small external strain, but polarization rotation is not a necessary condition. © 2012 American Physical Society.


Jiang J.,Hohai University | Yuan Y.,China University of Mining and Technology
Magazine of Concrete Research | Year: 2013

Variations of temperature and moisture content in concrete arise as the effects of climate load in a natural environment; because it can be easily measured, relative humidity is often used as a transition index reflecting moisture content. Determination of the relationship between moisture content and temperature/humidity in concrete is of great significance in accurate prediction of the durability of reinforced concrete structures. Under constant temperature conditions, measurements of both relative humidity and moisture content in concrete are carried out synchronously. Results show that pore water saturation, considered as the characterisation of moisture content, changes non-linearly with relative humidity in concrete; the evolution is significantly influenced by the water- cement ratio and temperature. Finally, based on experimental results and theoretical analysis, a model of the relationship between pore water saturation, temperature and relative humidity in concrete is established, and its feasibility is verified through an independent test.


Jiang J.-H.,Hohai University | Yuan Y.-S.,China University of Mining and Technology
Construction and Building Materials | Year: 2013

A long-term test on the steel corrosion in concrete was conducted under the sheltered conditions of a natural climate environment. A synchronous test under the sheltered and unsheltered conditions was performed to determine the microenvironment response and steel corrosion in concrete. The effect of environmental climate on the steel corrosion rate in concrete was further determined. The results show that the steel corrosion rate in concrete fluctuates and is time-dependent under natural climatic conditions. The changes of environmental conditions in the concrete microenvironment are less than those in a natural climate environment, particularly relative humidity. The steel corrosion rate in concrete is directly affected by the microenvironment of concrete, which depends on the random fluctuations of natural climate. Temperature is the primary climatic factor that affects the steel corrosion rate in concrete under an atmospheric environment. The pore water saturation of concrete is also a key factor that causes the differences between the steel corrosion rates in concrete under sheltered and unsheltered conditions. A prediction strategy for the steel corrosion rate in concrete under natural climate is proposed based on the effects of environment on the corrosion rate as well as on the responses of the concrete microenvironment. © 2013 Elsevier Ltd. All rights reserved.


Qiu X.-Y.,China University of Mining and Technology | Zhuang Q.-C.,China University of Mining and Technology | Zhang Q.-Q.,China University of Mining and Technology | Cao R.,China University of Mining and Technology | And 3 more authors.
Physical Chemistry Chemical Physics | Year: 2012

The processes of extraction and insertion of lithium ions in LiCoO 2 cathode are investigated by galvanostatic cycling and electrochemical impedance spectroscopy (EIS) at different potentials during the first charge/discharge cycle and at different temperatures after 10 charge/discharge cycles. The spectra exhibit three semicircles and a slightly inclined line that appear successively as the frequency decreases. An appropriate equivalent circuit is proposed to fit the experimental EIS data. Based on detailed analysis of the change in kinetic parameters obtained from simulating the experimental EIS data as functions of potential and temperature, the high-frequency, the middle-frequency, and the low-frequency semicircles can be attributed to the migration of the lithium ions through the SEI film, the electronic properties of the material and the charge transfer step, respectively. The slightly inclined line arises from the solid state diffusion process. The electrical conductivity of the layered LiCoO 2 changes dramatically at early delithiation as a result of a polaron-to-metal transition. In an electrolyte solution of 1 mol L -1 LiPF 6-EC (ethylene carbonate)DMC (dimethyl carbonate), the activation energy of the ion jump (which is related to the migration of the lithium ions through the SEI film), the thermal activation energy of the electrical conductivity and the activation energy of the intercalation/deintercalation reaction are 37.7, 39.1 and 69.0 kJ mol -1, respectively. © the Owner Societies 2012.


Xu S.-D.,China University of Mining and Technology | Zhuang Q.-C.,China University of Mining and Technology | Tian L.-L.,China University of Mining and Technology | Qin Y.-P.,China University of Mining and Technology | And 2 more authors.
Journal of Physical Chemistry C | Year: 2011

The first lithium-ion insertion and extraction processes of a graphite electrode at different potentials were studied by electrochemical impedance spectroscopy (EIS). The results revealed that, below the potential of 0.65 V during the first lithiation, three semicircles were observed in the Nyquist plots; namely, two semicircles appeared in the middle-frequency region. This new phenomenon has been investigated through the detailed analysis of the change of kinetic parameters obtained from simulating the experimental EIS data for lithium-ion insertion and extraction in graphite as a function of potential. It has been found that the two semicircles in the middle-frequency region were strongly potential-dependent, and they were both attributed to the charge-transfer process. Evidence was presented (supported by model calculation) that the two semicircles observed in the middle-frequency region originated from the nonhomogeneous, multilayered porous microstructure of the graphite electrode, which resulted from a parallel combination of impedance response of the thinner parts and thicker parts of the electrode. © 2011 American Chemical Society.


Wu W.,University of Tennessee at Knoxville | Wu W.,Oak Ridge National Laboratory | Qiao H.,McMaster University | An K.,Oak Ridge National Laboratory | And 4 more authors.
International Journal of Plasticity | Year: 2014

In the present research, the real-time in-situ neutron diffraction measurements under a continuous-loading condition and elastic-viscoplastic self-consistent (EVPSC) polycrystal modeling were employed to study the deformation dynamics and the effect of the deformation history on plastic deformation in a wrought magnesium alloy. The experimental results reveal that pre-deformation delays the activation of the tensile twinning during the subsequent compression, mainly resulting from the residual strains. Detwinning does not occur until the applied stress exceeds the tensile yield strength during the reverse loading. It is believed that the grain rotation plays an important role in the elastic region during the reverse loading. The EVPSC model, which has been recently updated by implementing the twinning and detwinning model, was employed to characterize the deformation mechanism during the strain-path changes. The simulation result predicts well the experimental observation from the real-time in-situ neutron diffraction measurements. The present study provides a new insight of the nature of deformation mechanisms in a hexagonal close-packed (HCP) structured polycrystalline wrought magnesium alloy, which has significant implications for future work on studying the deformation mechanisms of HCP-structured materials. © 2014 Elsevier Ltd. All rights reserved.


Zhang X.-J.,Shandong University of Technology | Zhang X.-J.,China University of Mining and Technology
Caikuang yu Anquan Gongcheng Xuebao/Journal of Mining and Safety Engineering | Year: 2011

Rock burst occurs in shallow part of surrounding rock such as loose, flake off, sound, rock-chip ejection, so it mainly belongs to splitting failure. For the splitting rock burst problem of integrated hard and brittle surrounding rocks, loading and unloading tests of true triaxial compression to simulate the actual stress evolution of surrounding rock and unload one-sided principal stress are conducted using the mineral of gabbro. In order to facilitate comparative analysis, the biaxial compression tests were carried out at the same time. Finally, the mechanism of splitting rock burst is analyzed based on the test results. Although the phenomena of splitting rock burst are gained by two kinds of test methods, the maximum principal stress needed for unloading splitting rock burst is much smaller than that of biaxial compression test; the scope of the two kinds of splitting rock burst is different and unloading splitting rock burst occurs near the unloading surface which is in accord with the actual situation of rock burst; intermediate principal stress plays an important role in splitting rock burst. The research findings provide a basis for analyzing the condition and mechanism of splitting rock burst.


Liu J.,Tsinghua University | Han R.,Tsinghua University | Zhao Y.,Tsinghua University | Wang H.,Tsinghua University | And 3 more authors.
Journal of Physical Chemistry C | Year: 2011

A new route to synthesize V-doped and V-N codoped titania nanocatalysts using a novel two-phase hydrothermal method applied in hazardous PCP-Na decomposition was reported. The physicochemical properties were characterized, indicating that the crystallite surface area increased after both first hydrothermal (FH) V impregnation and second hydrothermal (SH) N implantation, whereas mesoporous framework shrinkage and enlargement resulted from FH and SH, respectively. ICP and EPR demonstrated that SH did not alter V content, but rather it induced paramagnetic V4+ increase. The V species was enhanced from the inner to the catalyst surface with V5+ as the dominant mode and the N dopant existed with substitutional nitrogen as the main structure. The optical red shift by low vanadium implantation was ascribed to the V2p state, mainly from V4+ species in the matrix. After SH incorporation, the substitutional N1s state, interstitial N-O state, and concomitant NOx were responsible for the strong visible absorption of V-N-TiO2. The photodegradation rates of PCP-Na by the remodified catalysts after SH were much larger than that of the mono-V-TiO2 precursors fabricated in FH. SHNV02, SHNV05, and SHNV10 exhibited 2.4, 1.6, and 3.1 times promotion toward PCP-Na decomposition, respectively. Moreover, other variations and the synergetic effects after two-phase treatments were adequately discussed and proven to be useful in facilitating photocatalytic promotion. This work provided a strategy for obtaining further enhancement of the synthesized catalyst by second-step modification to achieve the deep removal effect of contaminants. © 2011 American Chemical Society.


Zhang D.-P.,China University of Mining and Technology | Zhang D.-P.,Shandong University of Technology | Zhang D.-P.,University of Science and Technology Beijing | Zhang L.-F.,China University of Mining and Technology | And 2 more authors.
Chemical Communications | Year: 2013

One cyanide-bridged W(iv)-Ni(ii) wheel-like complex and two three-dimensional (3D) networks can be directly synthesized based on K 4[W(CN)8] and [Ni(L)](ClO4)2 precursors by controlling the quantity of water in organic solvent. The water-controlled single-crystal structural transformations among these complexes are described. © The Royal Society of Chemistry 2013.


Kong X.,Tsinghua University | Shi Z.,China University of Mining and Technology | Lu Z.,Tsinghua University
Construction and Building Materials | Year: 2014

Polymer nano-particles (PNPs) with particle size range of 29.4-52.7 nm were synthesized via emulsion polymerization. The mini-cone tests were conducted to evaluate the dispersion capability of PNPs in fresh cement pastes (fcps). Interactions of PNPs with cement were studied by measurements of total organic carbon, zeta potential, transmission electron microscopy, calorimetry and mercury intrusion porosimetry. Results show that the prepared PNPs can be adsorbed on to cement surface and improve fluidity of fcps effectively. The addition of PNPs leads to lesser retardation effect on cement hydration than popularly used polycarboxylate superplasticizers and reduces pore connectivity of micro-pores in hardened cement pastes. © 2014 Elsevier Ltd. All rights reserved.


Chen Y.,Tsinghua University | Huang Z.-H.,Tsinghua University | Yue M.,China University of Mining and Technology | Kang F.,Tsinghua University
Nanoscale | Year: 2014

Organic nanostructures in terms of porphyrin building blocks have shown great potential in visible-light photocatalytic applications because of their optical, electrical, and catalytic properties. Graphenes are known to provide a high-quality two-dimensional (2D) support for inorganic semiconductor nanostructures to increase the adsorption capability of the photocatalysts and an electron-transfer medium with attractive potential to enhance photogenerated charge separation. A combination of porphyrin nanostructures with graphene sheets, particularly in the form of free-standing films, is highly desirable due to its photocatalysing feasibility and convenience. Toward this aim, we demonstrate a facile method to integrate porphyrin (meso-tetra(p-hydroxyphenyl) porphyrin, p-THPP) nanoparticles (NPs) into macroscopic graphene (reduced graphene oxide, rGO) films through vacuum filtration of the co-colloids of graphene oxide (GO) and p-THPP nanoparticles (NPs) followed by gaseous reduction. The obtained p-THPP/rGO nanohybrid film exhibits enhanced visible-light photocatalytic activity compared to each moiety of the hybrid, and this photocatalyst can be easily separated and recycled for successive use with excellent stability. The results show that this facile fabrication of the p-THPP/rGO nanohybrid film makes it available for high-performance optoelectronic applications, as well as for device integration. © 2013 The Royal Society of Chemistry.


Shi Q.,South China University of Technology | Peng F.,South China University of Technology | Liao S.,South China University of Technology | Wang H.,South China University of Technology | And 4 more authors.
Journal of Materials Chemistry A | Year: 2013

Carbon materials have received an increasing amount of attention due to their low cost, long-term stability, and high electrocatalytic activity in catalyzing the cathodic oxygen reduction reaction (ORR). However, most of the carbon catalysts have exhibited their excellent activity only in alkaline media, which greatly hinders their practical application in polymer electrolyte membrane fuel cells (PEMFCs). In order to break the restriction of alkaline conditions, sulfur and nitrogen doped carbon nanotubes (SN-CNTs) were designed and successfully prepared via annealing of a mixture composed of nitrogen doped carbon nanotubes (N-CNTs) and sulfur. The result showed the as-prepared SN-CNTs have an enhanced ORR activity in both acidic and alkaline media compared with N doped CNTs (N-CNTs). This report also provides a new approach to explore low-cost electrocatalysts for practical fuel cell applications. © 2013 The Royal Society of Chemistry.


Liu X.,China University of Mining and Technology | Yin Z.,Sun Yat Sen University
Mathematical Methods in the Applied Sciences | Year: 2014

We consider a generalization of Camassa-Holm-type equation including the Camassa-Holm equation and the Novikov equation. We mainly establish the existence of solutions in lower order Sobolev space Hs(ℝ) with 1


Tian L.,China University of Mining and Technology | Zhuang Q.,China University of Mining and Technology | Li J.,China University of Mining and Technology | Wu C.,China University of Mining and Technology | And 2 more authors.
Electrochimica Acta | Year: 2012

An easy and effective strategy is developed to produce α-Fe 2O 3 nanoparticles (NPs) anchored on conducting graphene sheets by a hydrothermal reaction, without any reducing agents. Scanning electron microscopy shows that the α-Fe 2O 3 NPs are 70-85 nm in size and homogeneously anchored on the graphene sheets. As high-performance anodes for lithium-ion batteries, the obtained material exhibits an excellent reversible capacity of ∼1050 mAh g -1 based on the total mass. Its cycling performance and rate capability are drastically improved, exhibiting a high charge capacity of 1000 ± 50 mAh g -1 with no noticeable capacity fading up to 100 cycles in the voltage range 0.1-3.0 V at 50 mA g -1. These results highlight the importance of the anchoring of NPs on graphene sheets for maximum use of electrochemically active Fe 2O 3 NPs and graphene for energy storage applications. © 2012 Elsevier Ltd. All rights reserved.


Wu L.-L.,China University of Mining and Technology | Nie J.-G.,Tsinghua University
Gongcheng Lixue/Engineering Mechanics | Year: 2010

The steel-concrete composite slab is becoming popular in the fields of building and bridge structures. Nevertheless, at present little study on the foundational performance of elastic stability of steel-concrete composite slab for all practical purposes is available, especially on its local buckling behavior. The maximal spacing of shear connectors (such as studs) is the most important factor to prevent the steel plate from local buckling before yielding, and it also makes steel plate and concrete slab behave as one. Based on model parameter analyses, the local buckling behavior of steel-concrete composite slab with simply supported edges in pure shear is studied by finite element methods. A calculating model steel plate with typical boundary is proposed to simulate the buckling performance of the steel plate surrounded by shear studs in the composite slab. The formula of maximal spacing of shear studs is deduced for the simply supported composite slab. The calculation result is slightly conservative.


Yang S.,China University of Mining and Technology | Yang S.,Hohai University | Jiang Y.,Hohai University
Mining Science and Technology | Year: 2010

Based on laboratory results of time-dependent mechanical behavior tests, we investigated short-term and mechanical creep behavior of sandstone, observed in conventional triaxial compression experiments at room temperature, using a servo-controlled rheology testing machine. Given our short-term experimental test results, we confirmed deviatoric creep stress levels of sandstone. Multiple deviatoric stress levels were applied in steps to each sample. Each deviatoric stress level before the final failed deviatoric stress was maintained for 48 h or longer. Time-dependent variations of axial strains of sandstone samples are discussed and evaluated. During the creep tests, complete tertiary creep curves of sandstone were observed under failed deviatoric stress levels with different confining pressures. Slices of coal in sandstone samples can lead to distinct tertiary creep deformation failure. © 2010 China University of Mining and Technology.


Zhuang Q.-C.,China University of Mining and Technology | Wei T.,China University of Mining and Technology | Du L.-L.,China University of Mining and Technology | Cui Y.-L.,China University of Mining and Technology | And 2 more authors.
Journal of Physical Chemistry C | Year: 2010

Electrochemical impedance spectra (EIS) for lithium ion insertion and deinsertion in spinel LiMn2O4 were obtained at different potentials and different temperatures during initial charge-discharge cycle. The results revealed that, at intermediate degrees of intercalation, three semicircles appeared in the Nyquist diagram. This new phenomenon has been investigated through EIS measurements as a function of temperature. It has found that the high frequency semicircle and the middle to high frequency semicircle begin to overlap each other above 20 °C, which indicates that the high frequency compressed semicircle commonly obtained at room temperature in the literature may consist of two semicircles. This signifies that the effects of the electronic and ionic transport properties of lithium intercalation materials clearly appear as separate features in the EIS spectra at low temperatures. A new equivalent circuit that includes elements related to the electronic and ionic transport, in addition to the charge transfer process, is proposed to simulate the experimental EIS data. The change of kinetic parameters for lithium ion insertion and deinsertion in spinel LiMn2O4 as a function of potential in the first charge-discharge cycle is discussed in detail, and a modified model is proposed to explain the impedance response of the insertion materials for lithium ion batteries. © 2010 American Chemical Society.


Wang J.,China University of Mining and Technology | Shi T.,China University of Mining and Technology | Yang X.,Chinese Ecological Civilization Research and Promotion Association | Han W.,Chinese Ecological Civilization Research and Promotion Association | Zhou Y.,Foreign Economic Cooperation Office China State Environmental Protection Administration
Chemosphere | Year: 2014

Biodegradation experiments were carried out with capsaicin to evaluate its degradability. The results show that capsaicin was readily biodegradable under aerobic conditions. The values of Kow and the calculated bioconcentration factor indicate that capsaicin have a low potential for bioconcentration. The fish acute toxicity tests conducted with Brachydanio rerio show LC50 for capsaicin was 5.98mgL-1. The tests of alga growth inhibition conducted with Selenastrum capricornutum suggest EC50 for capsaicin was 114mgL-1. The calculated PNEC (Predicted No Effect Concentration) was 4.9×10-4 mgL-1. The average PEC (Predicted Environmental Concentration) for OECD-EU commercial harbor and marina were 3.99×10-6 and 2.49×10-5mgL-1, respectively. These indicate that the PEC was much less than the PNEC for capsaicin. The low Kp value of capsaicin suggests the data about the risk of capsaicin to sediment organisms can be waived. According to the results from the analysis of the degradation, bioaccumulation, toxicity and accumulation in sediment, it can be concluded that capsaicin used as active substance for antifouling system on ships poses relatively low risk to marine environment. © 2013 Elsevier Ltd.


Yin S.,Wuhan University of Technology | Yin S.,China University of Mining and Technology | Mu S.,Wuhan University of Technology | Pan M.,Wuhan University of Technology | Fu Z.,Wuhan University of Technology
Journal of Power Sources | Year: 2011

Pt nanoparticles supported on TiB 2 conductive ceramics (Pt/TiB 2) have been prepared through a liquid reduction method, where the TiB 2 surfaces are stabilized with perfluorosulfonic acid. The prepared Pt/TiB 2 catalyst is characterized with X-ray diffraction (XRD) and TEM techniques, and a rotating disk electrode (RDE) apparatus. The Pt nanoparticles are found to uniformly disperse on the surface of the TiB 2 particles with narrow size distribution. The electrochemical stability of Pt/TiB 2 is evaluated and found highly electrochemically stable compared to a commercial Pt/C catalyst. Meanwhile, the catalyst also shows comparable performance for oxygen reduction reaction (ORR) to the Pt/C. The mechanism of the remarkable stability and comparable activity for ORR on Pt/TiB 2 is also proposed and discussed. © 2011 Elsevier B.V.


Sun Z.,China University of Mining and Technology | Sun Z.,Queensland University of Technology | Bai C.,Inner Mongolia University of Science and Technology | Zheng S.,China University of Mining and Technology | And 2 more authors.
Applied Catalysis A: General | Year: 2013

Three porous amorphous silica minerals, including diatomite, opal and porous precipitated SiO2 were adopted to prepare supported TiO 2 catalysts by hydrolysis-deposition method. The prepared compound materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Through morphology and physical chemistry properties of the resulting TiO 2/amorphous SiO2 catalysts, it was proposed that the nature of silica supports could affect the particle size and the crystal form of TiO2 and then further influence the photocatalytic property of TiO2/amorphous SiO2 catalysts. The catalytic properties of these porous amorphous silica supported photocatalysts (TiO2/ SiO2) were investigated by UV-assisted degradation of Rhodamine B (RhB). Compared with pure TiO2 (P25) and the other two TiO 2/amorphous SiO2 catalysts, TiO2/diatomite photocatalyst exhibits better catalytic performance at different calcined temperatures, the decoloration rate of which can be up to over 85% even at a relatively low calcined temperature. The TiO2/diatomite photocatalyst possesses mixed-phase TiO2 with relatively smaller particles size, which might be responsible for higher photocatalytic activity. Moreover, the stable and much inerter porous microstructure of diatomite could be another key factor in improving its activity. © 2013 Elsevier B.V. All rights reserved.


Tian L.-L.,China University of Mining and Technology | Wei X.-Y.,China University of Mining and Technology | Zhuang Q.-C.,China University of Mining and Technology | Jiang C.-H.,China University of Mining and Technology | And 5 more authors.
Nanoscale | Year: 2014

A facile bottom-up strategy was developed to fabricate nitrogen-doped graphene sheets (NGSs) from glucose using a sacrificial template synthesis method. Three main types of nitrogen dopants (pyridinic, pyrrolic and graphitic nitrogens) were introduced into the graphene lattice, and an inimitable microporous structure of NGS with a high specific surface area of 504 m 2 g-1 was obtained. Particularly, with hybrid features of lithium ion batteries and Faradic capacitors at a low rate and features of Faradic capacitors at a high rate, the NGS presents a superior lithium storage performance. During electrochemical cycling, the NGS electrode afforded an enhanced reversible capacity of 832.4 mA h g-1 at 100 mA g -1 and an excellent cycling stability of 750.7 mA h g-1 after 108 discharge-charge cycles. Furthermore, an astonishing rate capability of 333 mA h g-1 at 10000 mA g-1 and a high rate cycle performance of 280.6 mA h g-1 even after 1200 cycles were also achieved, highlighting the significance of nitrogen doping on the maximum utilization of graphene-based materials for advanced lithium storage. © 2014 the Partner Organisations.


Deng J.,Tsinghua University | Wen X.,Tsinghua University | Wang Q.,China University of Mining and Technology
Materials Research Bulletin | Year: 2012

Fe 3O 4-multi-walled carbon nanotubes (Fe 3O 4-MWCNTs) hybrid materials were synthesized by a solvothermal process using acid treated MWCNTs and iron acetylacetonate in a mixed solution of ethylene glycol and ultrapure water. The materials were characterized using X-ray powder diffraction, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, and vibrating sample magnetometry. The results showed that a small amount of water in the synthesis system played a role in controlling crystal phase formation, size of Fe 3O 4, and the homogeneous distribution of the Fe 3O 4 nanoparticles deposited on the MWCNTs. The Fe 3O 4 nanoparticles had diameters in the range of 4.2-10.0 nm. They displayed good superparamagnetism at room temperature and their magnetization was influenced by the reaction conditions. They were used as a Fenton-like catalyst to decompose Acid Orange II and displayed a higher activity than nanometer-size Fe 3O 4. © 2012 Elsevier Ltd. All rights reserved.


Park Y.,Queensland University of Technology | Sun Z.,Queensland University of Technology | Sun Z.,China University of Mining and Technology | Ayoko G.A.,Queensland University of Technology | Frost R.L.,Queensland University of Technology
Chemosphere | Year: 2014

Remediation of bisphenol A (BPA) from aqueous solutions by adsorption using organoclays synthesized from montmorillonite (MMT) with different types of organic surfactant molecules was demonstrated. High adsorption capacities of the organoclays for the uptake of BPA were observed and these demonstrated their potential application as strong adsorbents for noxious organic water contaminants. The adsorption of BPA was significantly influenced by pH, with increased adsorption of BPA in acidic pH range. However, the organoclays intercalated with highly loaded surfactants and/or large surfactant molecules were less influenced by the pH of the environment and this was thought to be due to the shielding the negative charge from surfactant molecules and the development of more positive charge on the clay surface, which leads to the attraction of anionic BPA even at alkaline pH. The hydrophobic phase created by loaded surfactant molecules contributed to a partitioning phase, interacting with BPA molecules strongly through hydrophobic interaction. Pseudo-second order kinetic model and Langmuir isotherm provided the best fit for the adsorption of BPA onto the organoclays. In addition, the adsorption process was spontaneous and exothermic with lower temperature facilitating the adsorption of BPA onto the organoclays. The described process provides a potential pathway for the removal of BPA from contaminated waters. © 2014 Elsevier Ltd.


Zhang Y.-R.,Tsinghua University | Kong X.-M.,Tsinghua University | Lu Z.-B.,China University of Mining and Technology | Lu Z.-C.,Tsinghua University | Hou S.-S.,University of Science and Technology of China
Cement and Concrete Research | Year: 2015

The traditional polycarboxylate (PC) superplasticizers are usually negatively charged polymers, in which the carboxylate functionalities are responsible for their adsorption on cement surface driven by electrostatic interaction. This paper investigates the impacts of the charge characteristics of PC co-polymers on their adsorption behaviors and the retardation effects on cement hydration. PC co-polymers with variation of their charge species were synthesized by co-polymerizing the macro-monomer with selected anionic and cationic monomers. Adsorption and impacts on cement hydration of the monomers, their homo-polymers and the PC co-polymers were studied in cement pastes by total organic carbon tests and calorimetry respectively. Results show that in cement pastes, no adsorption and retardation were observed for the monomers while for their corresponding homo-polymers, different extents of adsorption and retardation were found. Charge characteristics of PC co-polymers strongly determine their adsorption behaviors and retardation effects, in the order of -COO- > SO3 - ≡ N+. © 2014 Elsevier Ltd. All rights reserved.


Yang D.H.,Tsinghua University | Wang N.,Tsinghua University | Liu E.,China University of Mining and Technology
Communications in Computational Physics | Year: 2012

In this paper, we propose a strong stability-preserving predictor-corrector (SSPC) method based on an implicit Runge-Kutta method to solve the acoustic- and elastic-wave equations. We first transform the wave equations into a system of ordinary differential equations (ODEs) and apply the local extrapolation method to discretize the spatial high-order derivatives, resulting in a system of semi-discrete ODEs. Then we use the SSPC method based on an implicit Runge-Kutta method to solve the semi-discrete ODEs and introduce a weighting parameter into the SSPC method. On top of such a structure, we develop a robust numerical algorithm to effectively suppress the numerical dispersion, which is usually caused by the discretization of wave equations when coarse grids are used or geological models have large velocity contrasts between adjacent layers. Meanwhile, we investigate the performance of the SSPC method including numerical errors and convergence rate, numerical dispersion, and stability criteria with different choices of the weighting parameter to solve 1-D and 2-D acoustic- and elastic-wave equations. When the SSPC is applied to seismic simulations, the computational efficiency is also investigated by comparing the SSPC, the fourth-order Lax-Wendroff correction (LWC) method, and the staggered-grid (SG) finite difference method. Comparisons of synthetic waveforms computed by the SSPC and analytic solutions for acoustic and elastic models are given to illustrate the accuracy and the validityof the SSPC method. Furthermore, several numerical experiments are conducted for the geological models including a 2-D homogeneous transversely isotropic (TI) medium, a two-layer elastic model, and the 2-D SEG/EAGE salt model. The results show that the SSPC can be used as a practical tool for large-scale seismic simulation because of its effectiveness in suppressing numerical dispersion even in the situations such as coarse grids, strong interfaces, or high frequencies. © 2012 Global-Science Press.


Lu X.,Tsinghua University | Li M.,Tsinghua University | Tang C.,China University of Mining and Technology | Feng C.,Water Resources University | Liu X.,Tsinghua University
Journal of Hazardous Materials | Year: 2012

A new electrochemical permeable reactive barrier (Electro-PRB) system for removal of hexavalent chromium [Cr(VI)] using Fe 0 meshes was developed. Electro-PRB was found to be effective for electrochemical depassivation of Fe 0 to remove Cr(VI) during treatment. During initial treatment, Cr(VI) removal rates decreased with time, due to loss of Fe 0 reactivity by mineral fouling. After Fe 0 was passivated, electrochemical depassivation was introduced for different electrolysis times to recover Fe 0 reactivity. It was found that there was approximately 100.4-131.3% initial removal rate recovery, due to the electrochemical break down of precipitates on the Fe 0 surfaces. During the treatment, the decreasing pH and increasing oxidation-reduction Potential (ORP) of the effluent implied the passivation of Fe 0 surfaces. Scanning electron microscope analysis of acid-washed, electrochemically depassivated, and passivated Fe 0 confirmed the efficiency of Elecro-PRB in the recovery Fe 0 reactivity. The results indicate that the Electro-PRB system proposed here is capable of recovering the reactivity of Fe 0, which may prolong the operation of Cr(VI) removal processes. © 2012 Elsevier B.V.


Han R.,Tsinghua University | Liu J.,Tsinghua University | Zhang Y.,Tsinghua University | Fan X.,China University of Mining and Technology | And 2 more authors.
Bioresource Technology | Year: 2012

A novel two-step technology, fast biophysical drying (BPD) coupling with fast pyrolysis (FP), was investigated for moisture removal and energy recovery from sewage sludge. For BPD, combined operations of extreme thermophilic amendment (with accelerated increasing and controllable maintenance of substrate temperature) and enhanced convective evaporation were conducted, both beneficial for moisture removal (moisture content reaching 23.1% for 7d) and organic preservation. Biophysical-dried sludge (BPDS) was characterized by homogeneous fine-particle morphology and well-developed porous microstructure. The synthesized BPDS particle preserved most organic components (92% volatile matters and 79% HHV of traditional thermal-dried sludge [TTDS]) attributable to the inhibitory effect of BPD adjustment, presenting considerable capacity for subsequent residue-derived energy. For FP, the distribution of products from BPDS pyrolysis indicated that syngas and char yields were higher than those of TTDS. The syngas from BPDS is a type of hydrogen-rich gas composed of 42.6vol.% H 2 at 900°C. © 2011 Elsevier Ltd.


Xin L.,Tsinghua University | Hong-ying H.,Tsinghua University | Ke G.,China University of Mining and Technology | Jia Y.,Tsinghua University
Ecological Engineering | Year: 2010

Microalgae have received much attention for the inorganic nutrient removal in tertiary treatment of domestic wastewater. Effect of different kinds of nitrogen sources on the growth and nitrogen/phosphorus removal properties of a newly isolated freshwater microalga, Scenedesmus sp. LX1, from a low-nutrient environment condition was studied and reported in this paper. The order of specific growth rate of the microalga with different nitrogen sources was NH4-N > urea-N > NO3-N. With nitrate or urea as nitrogen source, the microalga could grow well and remove both nitrogen and phosphorus efficiently (90% nitrogen and nearly 100% phosphorus were removed). However, with ammonium as the nitrogen source, the maximum algal density was relatively low, and the nitrogen and phosphorus removal efficiencies were as low as 31.1% and 76.4%, respectively. This was caused by the inhibitory effect of algal culture's acid pH due to H+ releasing from NH4 + during algal cultivation process. © 2009 Elsevier B.V. All rights reserved.


Chang L.,Shanghai Ocean University | Chang L.,China University of Mining and Technology | Jin S.,Chinese Academy of Sciences | He X.,Hohai University
IEEE Transactions on Geoscience and Remote Sensing | Year: 2014

Water vapor variations affect the interferometric synthetic aperture radar (InSAR) signal transmission and the accuracy of the InSAR measurements. The Moderate Resolution Imaging Spectroradiometer (MODIS) near infrared (nIR) water vapor product can correct InSAR atmospheric effects effectively, but it only works for the synthetic aperture radar (SAR) images acquired during the daytime. Although the MODIS infrared (IR) water vapor product owns poorer accuracy and spatial resolution than the nIR product, it is available for daytime as well as nighttime. In order to improve the accuracy of water vapor measurements from the MODIS IR product, a differential linear calibration model (DLCM) has been developed in this paper. The calibrated water vapor measurements from the IR product are then used for wet delay map production and nighttime overpass SAR interferogram atmospheric correction. Results show that the accuracy of the MODIS IR product can be improved effectively after calibration with the DLCM, and the derived wet delays are more suitable for InSAR atmospheric correction than original measurements from the IR product. Furthermore, a MODIS altitude-correlated turbulence model (MATM) is incorporated to correct the atmospheric effects from another descending ASAR interferogram. Results show that the MATM can reduce altitude-dependent water vapor artifacts more effectively than the traditional correction method without the need to incorporate the altitude information. © 1980-2012 IEEE.


Li Y.,Tsinghua University | Qi H.,Tsinghua University | Wang J.,China University of Mining and Technology
Fuel | Year: 2012

A high performance CaO/bio-based sorbent that resists attrition was developed to reduce the calcium losses and pressure drop in a circulating fluidized bed (CFB) for flue gas desulfurization (FGD). The calcium conversion of the CaO/bio-based sorbent is higher than that of pure lime, since the biomass acts as a dispersion medium in the lime to prevent agglomeration of the lime particles and to reduce the lime particle size. The study on the attrition characteristics of the sorbent in a bubbling fluidized bed shows that the attrition fraction of the CaO/bio-based sorbent is reduced to 32% compared with 100% for the sorbent without biomass, since the biomass and lime produces hydrated calcium silicate which changes the pore structure of the sorbents. This pore structure also improves the reaction rate. Biomass ash melting rearranges the lime structure and enhances the cohesive forces between particles resulting in less particle attrition. The reduced attrition fraction of the sorbents is related to the high SiO 2 and K 2O fractions in the biomass. The CaO/bio-based sorbent is a promising sorbent with high calcium conversion and reaction rate, small attrition fraction and improved structural properties. © 2011 Elsevier Ltd. All rights reserved.


Yin S.,China University of Mining and Technology | Luo L.,China University of Mining and Technology | Xu C.,China University of Mining and Technology | Zhao Y.,China University of Mining and Technology | And 2 more authors.
Journal of Power Sources | Year: 2012

In this work an efficient functionalizing method of carbon nanotubes (CNTs) by intermittent microwave heating (IMH) KOH media is reported. The performance of such modified CNTs as Pt electrocatalysts supports is demonstrated. FTIR spectrum and Raman spectrum are used to investigate the surface state of the CNTs. TEM technology is employed to study the dispersion of Pt particles for the prepared electrocatalysts. Meanwhile cyclic voltammetry and chronopotentiometry measurements are adopted to investigate the corresponding activity and stability of the electrocatalysts. The results indicate that the CNTs functionalized by the IMH method in the form of 15s-ON/10s-OFF for pulse 20 repetitions used as electrocatalysts supports shows significantly higher activity and stability towards methanol electrooxidation in comparison with the CNTs decorated in other forms in the present study. The present method is simple and economic and displays a probability of mass production for supporting materials and electrocatalysts as well. © 2011 Elsevier B.V. All rights reserved.


Li C.,Tsinghua University | Wan J.,China University of Mining and Technology | Sun H.,Tsinghua University | Sun H.,Pacific University in Oregon | Li L.,Tsinghua University
Journal of Hazardous Materials | Year: 2010

In order to comprehensively utilize coal gangue as the main raw material in cementitious materials, improving its cementitious activity is a question of fundamental importance. In this paper, we present a new compound mechanical-hydro-thermal activation (CMHTA) technology to investigate the activation effect of coal gangue, and the traditional mechanical-thermal activation (TMTA) technology was used as reference. The purpose of this study is to give a detailed comparison between these two methods with regard to the mineral composition, crystal structure and microstructure, by XRD, IR, MAS NMR, XPS and mechanical property analysis. The prepared coal gangue based blended cement, containing 52% of activated coal gangue C (by CMHTA technology), has a better mechanical property than activated coal gangue T (by TMTA technology) and raw coal gangue. The results show that both of the TMTA and CMHTA technologies can improve the cementitious activity of raw gangue greatly. Moreover, compared with TMTA, the mineral phases such as feldspar and muscovite in raw coal gangue were partially decomposed, and the crystallinity of quartz decreased, due to the effect of adding CaO and hydro-thermal process of CMHTA technology. © 2010 Elsevier B.V.


Liu R.,China University of Mining and Technology | Zhang F.,China University of Mining and Technology | Su W.,China University of Mining and Technology | Zhao H.,China University of Mining and Technology | Wang C.-A.,Tsinghua University
Solar Energy Materials and Solar Cells | Year: 2015

The porous mullite/Na2SO4 composites with both novel structure and improved heat storage properties were successfully prepared by infiltration of the molten Na2SO4 into the porous mullite matrix, which was fabricated by TBA-based freezing casting method. The effects of fabrication parameters on pore structure of the porous mullite matrix, the infiltration ratio of molten Na2SO4 and heat storage properties of the composites were investigated extensively. The results show that the infiltration ratio of the molten Na2SO4 decreases with decreasing the porosity and increasing the infiltration temperature and the average pore size of the porous mullite matrix. While it increases initially with increases of the infiltration time, and tends to remain constant thereafter. The optimal infiltration temperature and infiltration time are 950 °C and 1 h, respectively. The unidirectionally aligned open pores in the porous mullite matrix benefit the infiltration process, and the higher infiltration ratio of the molten Na2SO4 and the relatively larger specific heat capacity of the mullite powders both contribute to the higher heat storage density of the composites. © 2014 Published by Elsevier B.V.


Song Y.,Tsinghua University | Ma S.,Beijing University of Technology | Yang X.,China University of Mining and Technology | Wang X.,Beijing University of Technology
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2011

The experiments of the deformation and failure of rock under the condition of uniaxial compression were carried out by using the white digital speckle correlation methods. According to the experimental data collected in different ways, the experiments were divided into two groups. A group of experiment investigated the deformation evolution process of rock loaded, the specimen surface speckles images were recorded by CCD camera, According to the calculation results, the rock deformation evolution was studied. The other group of experiment investigated the deformation evolution process of the transient of rock damage; the specimen surface speckles images were recorded by adopting high speed cameras. By adopting the different times speckle images as reference frame, the plastic hardening to peak stage deformation evolution characteristics and the peak to destroy phase analysis of deformation evolution characteristics were carried out. At the same time, some quantitative parameters were obtained in the experiments, such as the value of deformation, the ratio of maximum and minimum values of the deformation in the deformation localization band, the ratio of deformation values inside and outside the deformation localization band, and the average speed of crack propagation.


Sun S.-W.,China University of Mining and Technology | Zhu B.-Z.,Northwest Research Institute Co. | Wang J.-C.,China University of Mining and Technology
Soils and Foundations | Year: 2013

As one of the measures for slope fast reinforcement, micropiles are always designed as a group. In this paper, an analytic model for the ultimate resistance of micropile is proposed, based on a beam-column equation and an existing p-y curve method. As such, an iterative process to find the bending moment and shear capacity of the micropile section has been developed. The formulation for calculating the inner force and deflection of the micropile using the finite difference method is derived. Special attention is given to determine the spacing of micropiles with the aim of achieving the ultimate shear capacity of the micropile group. Thus, a new design method for micropiles for earth slope stabilization is proposed that includes details about choosing a location for the micropiles within the existing slope, selecting micropile cross section, estimating the length of the micropile, evaluating the shear capacity of the micropiles group, calculating the spacing required to provide force to stabilize the slope and the design of the concrete cap beam. The application of the method to an embankment landslide in Qinghai province, China, is described, and monitoring data indicated that slope movement had effectively ceased as a result of the slope stabilization measure, which verified the effectiveness of the design method. © 2013 The Japanese Geotechnical Society. Production and hosting by Elsevier B.V. All rights reserved.


Zhao Y.,Jilin University | Cheng D.-F.,Jilin University | Yang X.-J.,China University of Mining and Technology
Advances in Mathematical Physics | Year: 2013

The local fractional Schrödinger equations in the one-dimensional Cantorian system are investigated. The approximations solutions are obtained by using the local fractional series expansion method. The obtained solutions show that the present method is an efficient and simple tool for solving the linear partial differentiable equations within the local fractional derivative. © 2013 Yang Zhao et al.


Yu Z.,University of California at Los Angeles | Zhang Q.,University of California at Los Angeles | Zhang Q.,China University of Mining and Technology | Li L.,University of California at Los Angeles | And 4 more authors.
Advanced Materials | Year: 2011

Shape-memory polymer light-emitting diodes (PLEDs) using a new silver nanowire/polymer electrode are reported. The electrode can be stretched by up to 16% with only a small increase in sheet resistance. Large deformation shape change and recovery of the PLEDs to various bistable curvatures result in minimal loss of electroluminescence performance. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA.


Nan W.,China University of Mining and Technology | Jianhua Z.,Tsinghua University
Acta Mathematica Scientia | Year: 2012

In this article, we consider the singular points of meromorphic functions in the unit disk. We prove the second fundamental theorem for the Ahlfors-Shimizu's characteristic in the unit disk in terms of Nevanlinna theory in the angular domains, and obtain the existence of T-points and Hayman T-points dealing with small functions as target. © 2012 Wuhan Institute of Physics and Mathematics.


Fan G.,China University of Mining and Technology | Zhang D.,China University of Mining and Technology | Zhang D.,Xinjiang University | Wang X.,China University of Mining and Technology
Resources, Conservation and Recycling | Year: 2014

In China, coal mine waste rock (CMWR) produced during coal mining and processing is still increasing significantly as a result of coal production which has huge environmental impact. CMWR reduction and utilization is a major issue for coal enterprises and government to reduce the surface footprint and the public environmental impact. Tiefa coalfield, an old coalfield with 60 years of coal exploitation, was selected as a case to study the methods to minimize the environmental impacts of CMWR piles in a short period. We argue that a systematic design on CMWR utilization is needed on the basis of a usage evaluation which takes consideration of CMWR source, compositions, and proximate analysis. Mine design is crucial and the base for reducing the CMWR generation at the headstream. Placing roadway into coal seam rather than rock, panel optimization, and parametric analysis for mining technique were conducted in Tiefa coalfield. A promising technology of CMWR backfill under the ground was employed with a resultant increase of coal recovery rate. The surface CMWR recycling depends on brick making, electricity generating, and rehabilitation of subsided land. The practice of the presented methods indicates that the CMWR piles on Tiefa coalfield may disappear in 3 years, which could significantly reduce the environmental impacts of CMWR dumps. The technologies conducted in Tiefa coalfield developed a model of CMWR reduction and utilization for Chinese coal mines. © 2013 Elsevier B.V.


Chiang F.-P.,State University of New York at Stony Brook | Mao L.,State University of New York at Stony Brook | Mao L.,China University of Mining and Technology
Meccanica | Year: 2014

Experimental stress analysis is a well established mechanics discipline dealing with measuring stress/strain in solids under load. Most techniques can only be applied to measuring strain of the surface. In this paper we review the development of techniques of using a random speckle patterns as a quantitative tool to mapping interior strain field of solids. After some elementary treatment of the basic principles of the speckle photography technique we describe three approaches that can probe the interior strain field of a transparent object. They are followed by a newly developed 3D strain measurement technique called digital volumetric speckle photography which can probe the interior of opaque materials as well. © 2014, Springer Science+Business Media Dordrecht.


Li W.,China University of Mining and Technology | Zhu Z.,China University of Mining and Technology | Ding S.X.,University of Duisburg - Essen
IET Control Theory and Applications | Year: 2011

In this study, the fault detection design of networked control systems (NCSs) considering time varying transmission delays, packet dropouts and quantisation errors is proposed. The design of the residual generator is formulated in the H∞ framework, where the transmission delays are described as polytopic uncertainties, quantisation errors are modelled as norm bounded uncertainties and packet dropouts are described as a binary Bernoulli process. The dynamics of residual generator is shown to be governed by a Markov jumping linear system with uncertainties, and then the residual generator is designed to be sensitive to system faults and robust against network-induced effects by applying a reference model strategy. A new residual evaluation scheme for NCSs is also proposed, where the absolute value of each residual signal is selected as the evaluation function and the threshold is computed by considering the mean value and variance of residual signals. In this way, the upper bound of the false alarm rate is ensured. © 2011 The Institution of Engineering and Technology.


Liu X.,China University of Mining and Technology | Peng G.,Harbin Institute of Technology | Hou Y.,China University of Mining and Technology
International Journal of Advanced Manufacturing Technology | Year: 2012

In order to realize automation and intelligence of product disassembly process in a virtual maintenance environment, an improved max-min ant system based methodology for product disassembly sequence planning was proposed. The feasibility graph for product disassembly process was defined and the mathematic model of product disassembly sequence planning problem was set up. Thus, the problem of product disassembly sequence planning was transformed into the problem of searching optimal path on a feasibility graph.Moreover, an improved max-min ant system based on the strategy of sorting elite ants was presented and the flowchart of the improved algorithm was designed. Finally, by simulation examples, the robustness and outperforming others of the improved algorithm were verified. © Springer-Verlag London Limited 2011.


Wang X.,China University of Mining and Technology | Dai S.,China University of Mining and Technology | Ren D.,China University of Mining and Technology | Yang J.,Xi'an University of Science and Technology
Applied Geochemistry | Year: 2011

This paper mainly describes mineralogy and geochemistry of coals from the Weibei coalfield in the southeastern Ordos Basin, North China. A number of Al-hydroxide/oxyhydroxide minerals were detected in the Late Carboniferous coals (Nos. 5, 10 and 11 coals), especially in the No. 10 coal. Aluminum-hydroxide/oxyhydroxide minerals (nordstrandite, boehmite and diaspore) in the No. 10 coal are associated with kaolinite, suggesting that these minerals are derived from the breakdown of kaolinite. A model in which Al-hydroxide/oxyhydroxide minerals form from the incongruent dissolution of kaolinite is presented. Nordstrandite and boehmite mainly occur as massive lenses (<500 μm in length). Diaspore appears as massive aggregates and as single euhedral crystals (<50 μm in length) in a kaolinite matrix. The presence of high temperature quartz, and zircon indicates that there was input of felsic volcanic debris during accumulation of the Late Carboniferous coals. These volcanic materials have also had a significant influence on the enrichment of certain trace elements including Li, Be, Ga, Zr, Nb, Mo, Sn, W and U in the Late Carboniferous coals (Nos. 5, 10, and 11 coals). SEM-EDX results show that Ga in the No. 10 coal (whole coal average 33.4 μg/g; n = 2) mainly occurs within Al-hydroxide/oxyhydroxide minerals (nordstrandite, boehmite, and diaspore), kaolinite and organic matter. © 2011 Elsevier Ltd.


Zhang Q.-F.,Jiangnan University | Wang D.-Q.,China University of Mining and Technology
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2012

Through physical model tests on colliery wastes improved by dynamic compaction, the dynamic strain gauge DH5939 is used to record the induced dynamic stress. The distribution and rules of the dynamic stress at different depths under different impact loadings and numbers of dynamic compaction are studied. It is shown that the dynamic stress has a single peak, and it has a significant decay to reach the peak under the impact loadings along the depth of the hammer. The decay speed of the horizontal dynamic stress is faster than that of the vertical one, and the range of influence of the vertical dynamic stress is more extensive than that of the horizontal one. The peak value of the dynamic stress attenuates quickly with the depth and similar in an approximate way of negative exponential decay law under the same tamping energy. In addition, for different measuring points, with the increase of compaction number, the dynamic stress tends to be stable after three to six blows. It may provide an efficient way to analyze the mechanism of dynamic compaction.


Huang Y.,China University of Mining and Technology | Han M.,China University of Mining and Technology | Yi R.,Xinjiang University
Construction and Building Materials | Year: 2012

Fly ash-based geopolymeric material with 5A zeolite as a filler was synthesized and the microsturture, compressive strength, formaldehyde adsorption property and efflorescence extent of the material obtained were investigated. The results showed that addition of 5A zeolite served to increase the compressive strength, which resulted from the micro-aggregate effect of fine zeolite particles on one hand and the enhancement of geopolymerization extent on the other hand. The Ca 2+ diffused from 5A zeolite through ion exchange with Na + in activator solution was assumed to be incorporated into the aluminosilicate framework as a charge-balancing cation to form a new fiber-like phase in the zeolite-contained geopolymer specimens. The fiber-like phase was suggested to be the amorphous zeolite-like hydrate products and the formation of this phase improved the geopolymerization through the mechanism of providing nucleation sites for geopolymer formation. In addition, the higher alkalinity of activator solution caused by the water adsorption of zeolite may also be responsible for the higher geopolymerization extent. The efflorescence extent of geopolymer specimen decreased with 5A zeolite addition, which is by reason of the Na + fixation into the zeolite structure through Ca 2+/Na + exchange and the lesser pore volume of macropores. Moreover, 5A zeolite in geopolymer still exhibited excellent formaldehyde adsorption ability. Therefore, fly ash-based geopolymer with 5A zeolite addition is potentially applicable to the development of new construction materials with the ability of purifying indoor air pollutants. © 2012 Elsevier Ltd. All rights reserved.


Hao M.,China University of Mining and Technology | Shi W.,Hong Kong Polytechnic University | Zhang H.,China University of Mining and Technology | Li C.,Central China Normal University
IEEE Geoscience and Remote Sensing Letters | Year: 2014

The level set method, because of its implicit handling of topological changes and low sensitivity to noise, is one of the most effective unsupervised change detection techniques for remotely sensed images. In this letter, an expectation-maximization-based level set method (EMLS) is proposed to detect changes. First, the distribution of the difference image generated from multitemporal images is supposed to satisfy Gaussian mixture model, and expectation-maximization (EM) is then used to estimate the mean values of changed and unchanged pixels in the difference image. Second, two new energy terms, based on the estimated means, are defined and added into the level set method to detect those changes without initial contours and improve final accuracy. Finally, the improved level set method is implemented to partition pixels into changed and unchanged pixels. Landsat and QuickBird images were tested, and experimental results confirm the EMLS effectiveness when compared to state-of-the-art unsupervised change detection methods. © 2013 IEEE.


Fan G.,China University of Mining and Technology | Zhang D.,China University of Mining and Technology | Zhang D.,Xinjiang University
Mine Water and the Environment | Year: 2014

Mining activities and geological conditions affect underground aquifers and surface water by different mechanisms. In this paper, we report three cases that illustrate some key factors and mechanisms to protect water supply during underground mining. Underground aquifers or surface water may be protected by controlling key strata movement, insuring an appropriate interburden thickness, and protecting the immediate aquiclude. © 2014, Springer-Verlag Berlin Heidelberg.


Gao Y.,China University of Mining and Technology | Gao F.,China University of Mining and Technology | Yeung M.-C.R.,California State Polytechnic University, Pomona
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2011

The discontinuous deformation analysis (DDA) method which discretizes the study objects to blocks is a of discrete medium computation methods. The original DDA is based on the small deformation and small rotation assumption which uses time step accumulation to simulate the large deformation and large rotation. So it will produce errors, especially when the large rotation occurs. The DDA program modified by finite deformation theory is conducted; and the results after each time step are modified by finite deformation geometric field. Two examples are carried out to validate the modified code. The results show that the modified code can handle the large rotation problem well and eliminate the rotation error; and it also can be used to solve the small displacement and small rotation problem. The modified code expands the application scope of DDA and can be used as an efficiency tool for engineering calculation.


Li H.,Harbin Institute of Technology | Lan C.M.,University of Science and Technology Beijing | Ju Y.,China University of Mining and Technology | Li D.S.,Dalian University of Technology
Journal of Bridge Engineering | Year: 2012

Corroded cables from a cable-stayed bridge in China that had been in service for 18years were employed to investigate the basic mechanical properties and residual fatigue life of wires and cables. First, the wires were randomly selected from the cables near the bottom anchorages and cut into segments as test specimens. The extent of corrosion of the wires was experimentally investigated. A tensile loading test was conducted on the wires to obtain the mechanical properties of the corroded single wires. The fatigue life of the corroded single wires was experimentally studied, and a dramatic degradation in fatigue life was observed. This phenomenon was interpreted using SEM images. Fatigue tests on two corroded cables were also conducted, and the test results indicated that the fatigue life of the cables had also decreased dramatically. A MonteCarlo simulation was conducted to obtain the fatigue life of cables. The simulation results indicated that the fatigue life of a cable was controlled by the small fraction of wires in the cable with the shortest fatigue lives. The fatigue life of a cable at a certain failure probability was dependent on the number of wires in the cable, but the mean fatigue life of a cable was not affected by the number of wires in the cable. © 2012 American Society of Civil Engineers.


Zhang X.,Institute of Information Security | Jiang J.,China University of Mining and Technology | Peng S.,CAS Institute of Automation
IEEE Transactions on Image Processing | Year: 2012

This paper proposes a new approach to the image blind super-resolution (BSR) problem in the case of affine interframe motion. Although the tasks of image registration, blur identification, and high-resolution (HR) image reconstruction are coupled in the imaging process, when dealing with nonisometric interframe motion or without the exact knowledge of the blurring process, classic SR techniques generally have to tackle them (maybe in some combinations) separately. The main difficulty is that state-of-the-art deconvolution methods cannot be straightforwardly generalized to cope with the space-variant motion. We prove that the operators of affine warping and blur commute with some additional transforms and derive an equivalent form of the BSR observation model. Using this equivalent form, we develop an iterative algorithm to jointly estimate the triple-coupled variables, i.e., the motion parameters, blur kernels, and HR image. Experiments on synthetic and real-life images illustrate the performance of the proposed technique in modeling the space-variant degradation process and restoring local textures. © 2011 IEEE.


Yang X.-J.,China University of Mining and Technology | Liao M.-K.,Xinjiang University | Chen J.-W.,Xinjiang University
Procedia Engineering | Year: 2012

In the present paper, local fractional continuous non-differentiable functions in fractal space are studied, and the signals in fractal-time space are reflectively investigated using the Yang-Fourier transforms based on the local fractional calculus. Two illustrative examples are given to elaborate the signal process and reliable results. © 2011 Published by Elsevier Ltd.


Jia M.-K.,China University of Mining and Technology | Jia M.-K.,Jiaozuo Coal Company
Caikuang yu Anquan Gongcheng Xuebao/Journal of Mining and Safety Engineering | Year: 2012

According to the geological condition of buried deep with thin bedrock coal seam in the 11011 working face of Zhao-Gu No.1 coal mine, the paper discussed the conditions of thin bedrock water gushing and running sand coal seam by using the coal mine field investigating and statistical analysis method. After analyzing and calculating the working face roof's structure instability mode by using the theories of 'masonry beam' and 'step beam' we have analyzed the overlying strata damage, migration evolution rule of fractures. The results show that and the height of the working face roof water fracture zones is about 48 m. Therefore, some preventive suggestions and measures have to been taken into practice when mining a coal within such a range. The measures can also guide other coal mines with similar geological condition.


Zhang Y.,China University of Mining and Technology | Tam H.,Hong Kong Baptist University
Journal of Mathematical Physics | Year: 2010

We introduce three kinds of column-vector Lie algebras L s(s=1,2,3). By making invertible linear transformations we get the corresponding three induced Lie algebras. According to the defined loop algebras L̃ s of the Lie algebras Ls(s=1,2,3), we establish three various isospectral problems. Then by applying Tu scheme, we obtain three different coupling integrable couplings of the Korteweg-de Vries (KdV) hierarchy and further reduce them to three kinds of explicit coupling integrable couplings of the KdV equation. One of the coupling integrable couplings of the KdV hierarchy of evolution equations possesses Hamiltonian structure obtained by using the quadratic-form identity and it is Liouville integrable. © 2010 American Institute of Physics.


Zhang Y.,China University of Mining and Technology | Tam H.,Hong Kong Baptist University
Journal of Mathematical Physics | Year: 2010

The first part in the paper reads that a three-dimensional Lie algebra is first introduced, whose corresponding loop algebra is constructed, for which isospectral problems are established. By employing zero curvature equations, a modified Kaup-Newell (mKN) soliton hierarchy of evolution equations is obtained. The corresponding hereditary operator and Hamiltonian structure are worked out, respectively. Then two types of enlarging semisimple Lie algebras isomorphic to the linear space R6 are followed to construct, one of them is a complex Lie algebra. Their corresponding loop algebras are also given so that two types of new isospectral problems are introduced to generate two kinds of integrable couplings of the above mKN hierarchy. The hereditary operators, Hamiltonian structures of the hierarchies are produced again, respectively. The exact computing formulas of the constant γ appearing in the trace identity and the variational identity are derived under the semisimple algebras. The second part of this paper is devoted to constructing two kinds of Lie algebras by using product of complex vectors, which are also isomorphic to the linear space R6. Then we make use of the corresponding loop algebras to produce two integrable hierarchies along with bi-Hamiltonian structures. From various aspects, we give some ways for constructing Lie algebras which have extensive applications in generating integrable Hamiltonian systems. © 2010 American Institute of Physics.


Miao S.D.,China University of Mining and Technology | Bergaya F.,French National Center for Scientific Research | Schoonheydt R.A.,Catholic University of Leuven
Philosophical Magazine | Year: 2010

In recent years, immense interest has been paid to biomolecular architecture with the aim of protein assembly in two dimensions on solid substrates, and the construction of clay-protein ultrathin films (CPUFs). An overview is provided of recent research on hybrid ultrafilms or nanofilms of clay mineral layers and protein molecules. Two techniques, layer-by-layer (LbL) assembly and Langmuir-Blodgett (LB), are presented. The films are characterised by UV-visible spectroscopy and atomic force microscopy (AFM). The amount of proteins incorporated in the films is obtained from UV-visible spectra. Film formation in the LB trough is studied by following the surface pressure versus time curves and the surface pressure versus area isotherms. With AFM the individual clay mineral layers and aggregates of protein molecules are resolved. © 2010 Taylor & Francis.


Guo P.,China University of Mining and Technology | Cheng Y.,China University of Mining and Technology | Jin K.,China University of Mining and Technology | Liu Y.,Anhui Hengyuan Coal Electricity Group Co.
Journal of Natural Gas Science and Engineering | Year: 2014

The fault has an important impact on coal bed methane (CBM) occurrence. The complexity of the fault exacerbates the variability of CBM occurrence, which increases the difficulty of mine gas prevention and thus threats to mining safety seriously. The coal-bearing strata in the Renlou coal mine located in the Linhuan mining area of the Huaibei coalfield have undergone three transformations caused by major tectonic movements since its formation. In addition, the large-angle tectonic stress superposition leads to structure characteristic and mechanical properties of faults transform in the area or just make it become multiplicity. The normal faults F3 and F7 and reverse fault F5 in southern Renlou coal mine are open structures. The coal seam between faults F7 and F5 is in the emission range of the two faults (partially in the superimposed range) in which a significant amount of gas escapes. The formation between faults F5 and F7 is horst, and it turns from NS to EW. The stress in the formation is large, which results in the presence of numerous fractures and cleats. Therefore, there is difference of methane occurrence between the two regions. Between faults F7 and F5, the gas pressure gradient of coal seam No. 72 is 0.00356MPa/m with a maximum value of 0.39MPa (-633.5m). However, the gas pressure gradient of coal seam No. 72 between faults F3 and F2 is 0.00726MPa/m and the maximum measured gas pressure is 1.7MPa (-692m). The relative methane emission (RME) of working face 7257 located between faults F7 and F5 was 2.01m3/t on average with a maximum value of 4.96m3/t. The average RME of working face II7211 located between faults F3 and F2 reached 12m3/t in the area of 0-600m away from F3 fault and increased to 30m3/t in the region of >600m away from fault F3. © 2013 Elsevier B.V.


Zhang Y.-F.,China University of Mining and Technology | Tam H.-W.,Hong Kong Baptist University
Communications in Theoretical Physics | Year: 2014

With the help of some reductions of the self-dual Yang Mills (briefly written as sdYM) equations, we introduce a Lax pair whose compatibility condition leads to a set of (2 + 1)-dimensional equations. Its first reduction gives rise to a generalized variable-coefficient Burgers equation with a forced term. Furthermore, the Burgers equation again reduces to a forced Burgers equation with constant coefficients, the standard Burgers equation, the heat equation, the Fisher equation, and the Huxley equation, respectively. The second reduction generates a few new (2 + 1)-dimensional nonlinear integrable systems, in particular, obtains a kind of (2 + 1)-dimensional integrable couplings of a new (2 + 1)-dimensional integrable nonlinear equation. © 2013 Chinese Physical Society and IOP Publishing Ltd.


Zhang Y.,China University of Mining and Technology | Tam H.,Hong Kong Baptist University
Journal of Mathematical Physics | Year: 2013

In this paper we introduce two new higher-dimensional variable-coefficient partial differential equations. One is a (2+1)-dimensional equation which can be reduced to the well-known KP equation which first occurs to the paper B. B. Kadomtsev and V. I. Petviashvili, "On the stability of solitary waves in weakly dispersive media," Sov. Phys. Dokl.15, 539 (1970), whose bilinear representation, Lax pairs, Bëcklund transformations, and infinite conservation laws are obtained respectively by using the Bell polynomials. Another one is a (3+1)-dimensional equation whose integrability is also investigated by us and whose Lax pairs, Bëcklund transformations, and infinite conservation laws are obtained, respectively. © 2013 American Institute of Physics.


Feng B.,Weifang University | Zhang Y.,China University of Mining and Technology
Advances in Mathematical Physics | Year: 2015

Based on some known loop algebras with finite dimensions, two different negative-order integrable couplings of the negative-order Korteweg-de Vries (KdV) hierarchy of evolution equations are generated by making use of the Tu scheme, from which the corresponding negative-order integrable couplings of the negative-order KdV equations are followed to be obtained. The resulting Hamiltonian structure of one negative integrable coupling is derived from the variational identity. © 2015 Binlu Feng and Yufeng Zhang.


Tam H.-W.,Hong Kong Baptist University | Zhang Y.,China University of Mining and Technology
Journal of Mathematical Physics | Year: 2012

Starting from an existed Lie algebra introduces a new Lie algebra A1 = {e 1, e 2, e 3} so that two isospectral Lax matrices are established. By employing the Tu scheme an integrable equation hierarchy denoted by IEH is obtained from which a few reduced evolution equations are presented. One of them is the mKdV equation. The elliptic variable solutions and three kinds of Darboux transformations for one coupled equation which is from the IEH are worked out, respectively. Finally, we take use of the Lie algebra A1 to generate eight higher-dimensional Lie algebras from which the linear integrable couplings, the nonlinear integrable couplings, and the bi-integrable couplings of the IEH are engendered, whose Hamiltonian structures are also obtained by the variational identity. Then further reduce one coupled integrable equation to get a nonlinear generalized mKdV equation. © 2012 American Institute of Physics.


Song S.,China University of Mining and Technology | Zhao Y.,China University of Mining and Technology | Luo Z.,China University of Mining and Technology | Tang L.,Tiandi Science And Technology
International Journal of Mining Science and Technology | Year: 2012

In order to study the settling mechanism of particles in an air-solid magnetically stabilized fluidized bed (MSFB) for separation, we carried out free settling and quasi-zero settling tests on the tracing particles. The results show that the main resistance forces as the tracing particles settled in an air-solid MSFB were motion resistance force and yield force. The motion resistance and yield forces greatly hindered the free settling of the particles by greatly decreasing the acceleration for settling process of the particles. The acceleration decreased from 3022.62 cm/s 2 to zero in 0.1 s, and in the end, the particles stopped in the air-solid MSFB. The yield force on particles increased with increasing the magnetic field intensity, resulting in decrease of the quasi-zero settling displacement. However, the yield force on particles decreased with increasing the fluidized air velocity, leading to increase of the quasi-zero settling displacement. When the structure and operating parameters of the air-solid MSFB were set up, the yield stress on particles stopped in an air-solid MSFB was a function of diameter and density of particles. The settling displacements of equal diameter particles increased with increasing their densities, and the settling displacements of equal density particles increased with increasing their diameters. © 2012 Published by Elsevier B.V. on behalf of China University of Mining & Technology.


Xu B.,Beijing Research Institute of Chemical Defense | Hou S.,China University of Mining and Technology | Cao G.,Beijing Research Institute of Chemical Defense | Wu F.,Beijing Institute of Technology | Yang Y.,Beijing Research Institute of Chemical Defense
Journal of Materials Chemistry | Year: 2012

Gelatin, a renewable animal derivative composed of various proteins, was used as a precursor for nitrogen-doped porous carbon with high surface areas for supercapacitors for the first time. The preparation procedure is very simple, including the carbonization of gelatin under inert atmosphere, followed by NaOH activation of the carbonized char at 600 °C for 1 h. The porosity and surface chemistry of the carbon depend strongly on the weight ratio of NaOH/char, with the specific surface area and nitrogen content varying between 323 and 3012 m 2 g -1 and between 0.88 and 9.26 at%, respectively. The unique microstructure and nitrogen functionalities enable the carbon to exhibit a high capacitance of up to 385 F g -1 in 6 mol L -1 KOH aqueous electrolytes, attributed to the co-contribution of double layer capacitance and pseudo-capacitance. It also shows excellent rate capability (235 F g -1 remained at 50 A g -1) and cycle durability, making it a promising electrode material for supercapacitors. This journal is © The Royal Society of Chemistry.


Zhang Y.,China University of Mining and Technology | Zhang Y.,University of Nevada, Las Vegas | Gong D.-W.,China University of Mining and Technology | Ding Z.-H.,University of Nevada, Las Vegas
Expert Systems with Applications | Year: 2011

This paper presents a new multi-objective optimization algorithm in which multi-swarm cooperative strategy is incorporated into particle swarm optimization algorithm, called multi-swarm cooperative multi-objective particle swarm optimizer (MC-MOPSO). This algorithm consists of multiple slave swarms and one master swarm. Each slave swarm is designed to optimize one objective function of the multi-objective problem in order to find out all the non-dominated optima of this objective function. In order to produce a well distributed Pareto front, the master swarm is developed to cover gaps among non-dominated optima by using a local MOPSO algorithm. Moreover, in order to strengthen the capability locating multiple optima of the PSO, several improved techniques such as the Pareto dominance-based species technique and the escape strategy of mature species are introduced. The simulation results indicate that our algorithm is highly competitive to solving the multi-objective optimization problems. © 2011 Elsevier Ltd. All rights reserved.


Xu B.,Beijing Research Institute of Chemical Defense | Yue S.,China University of Mining and Technology | Sui Z.,Beijing Institute of Technology | Zhang X.,Beijing Institute of Technology | And 3 more authors.
Energy and Environmental Science | Year: 2011

Graphene oxide, an intermediate during graphene synthesis by a modified Hummers's method, exhibits higher capacitance, up to 189 F g -1, than graphene due to an additional pseudo-capacitance effect of attached oxygen-containing functional groups on its basal planes. Taking its higher capacitance, lower cost and shorter processing time into consideration, graphene oxide may be a better choice than graphene as an electrode material for supercapacitors. © 2011 The Royal Society of Chemistry.


Yang Z.,China University of Mining and Technology | Yang Z.,University of South Carolina | Yang C.,University of South Carolina | Jin C.,University of South Carolina | And 2 more authors.
Electrochemistry Communications | Year: 2011

Ba0.9Co0.7Fe0.2Nb0.1O 3-δ (BCFN) perovskite material was synthesized and evaluated as cathode for La0.8Sr0.2Ga0.83Mg 0.17O3-δ (LSGM) electrolyte supported intermediate temperature solid oxide fuel cells (IT-SOFCs). X-ray diffraction results showed that BCFN was chemically compatible with the LSGM electrolyte. Maximum power densities of 0.36, 0.57, 0.80 and 1.1 W/cm2 were obtained for LSGM electrolyte supported cells with BCFN as cathode and Ni-GDC as anode operated at 650, 700, 750 and 800 °C, respectively. Further, the cell performance was stable under a constant current of 0.6 A/cm2 for over 204 h at 750 °C. © 2011 Elsevier B.V. All rights reserved.


Yang Z.,China University of Mining and Technology | Xu N.,China University of Mining and Technology | Han M.,China University of Mining and Technology | Chen F.,University of South Carolina
International Journal of Hydrogen Energy | Year: 2014

Solid oxide fuel cell (SOFC) has experienced a growing interest in the last few decades because of generating energy more efficiently than the conventional combustion of fossil fuels. By using the same material as anode and cathode of SOFC (symmetric fuel cell), the production of reliable and repeatable cells would be simpler. In this work, La0.4Sr0.6Co0.2Fe0.7Nb0.1O3-δ (LSCFN) perovskite has been prepared and evaluated as both cathode and anode material of symmetric fuel cell. The results of symmetric fuel cell show that a maximum peak power density of 500 mW cm-2 has been achieved and the total electrode polarization resistances of the cell is only 0.22 Ω cm2 at 850 °C which is much lower than that of typical symmetric fuel cell with La0.75Sr0.25Cr0.5Mn0.5O3-δ as electrode material. All of these results indicate that LSCFN can potentially be a promising candidate for the electrode material of symmetric fuel cell. © 2014.


Zhao H.-B.,China University of Mining and Technology | Chen L.-J.,Henan Polytechnic University
Yantu Lixue/Rock and Soil Mechanics | Year: 2011

Taking limestone for research objects, the thermal expansion property is studied under high temperature; the porosity, ultrasonic wave velocity and elemental composition are studied in order to find out the reason caused thermal expansion. The results show that: the limestone produces thermal expansion under high temperature; the curves between thermal expansion and test time includes four steps, size of thermal expansion is determined by temperature; and the relation is nonlinear; the porosity increases as temperature increases after high temperature; it can be divided into two stages based on division temperature of 500°C, including slow increase step and rapid increase step; the test of ultrasonics shows that the law of wave velocity is complex wavy type after high temperature; the test of elemental composition shows the contents of key elements in limestone samples has a larger change; the change of both porosity and elemental composition is the key reason causing thermal expansion of limestone under high temperature.


Li Z.-K.,China University of Mining and Technology | Zong Z.-M.,China University of Mining and Technology | Yan H.-L.,China University of Mining and Technology | Wei Z.-H.,Washington State University | And 2 more authors.
Fuel | Year: 2014

Ethanol-soluble portion (ESP) from Zhaotong lignite ethanolysis at 305 °C was analyzed with a positive-ion electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS). The range of molecular mass distribution is from m/z 100 to 600 with the center around m/z 330. Assignment of molecular formulae reveals that the main nitrogen-containing species with relative content of 86.4% are most probably basic nitrogen compounds (BNCs) ionized during ESI in positive-ion mode. The BNCs are N1Ox (x = 0-5) and N2Oy (y = 0-2) with 0-14 double bond equivalent (DBE) values and 9-39 carbon numbers. According to DBE distributions, pyridines and quinolines should be predominant BNCs in the ESP. In addition, amines (DBE < 4) were also identified in the ESP. The average DBE values are 6-8 for N1Ox class species and 7 and 8 for N2Ox class species, indicating that pyridines (or quinolones) and quinolines with an amino group are characteristic structures for N1Ox and N2Ox classes, respectively. Positive-ion ESI FT-ICR MS proved to be a powerful tool for identifying BNCs in coal-derived liquids. © 2014 Elsevier Ltd. All rights reserved.


Zhang Y.,Henan Polytechnic University | Liu Q.,China University of Mining and Technology | Zhang Q.,Henan Polytechnic University | Lu Y.,Henan Polytechnic University
Applied Clay Science | Year: 2010

A series of highly filled natural rubber (NR) composites based on silane modified kaolin (SMK), precipitated silica (PS) and their mixed-compound additions (SMK + PS) were prepared by melt blending. The transmission electron microscopy (TEM) was employed to characterize the NR composites. The kaolinite particles were finely dispersed into the natural rubber matrix and arranged in parallel orientation. Compared to the pure NR, these highly filled NR/SMK composites exhibited outstanding mechanical properties, excellent gas barrier properties and much higher thermal stability. The gas barrier properties of NR composites with SMK and PS were much higher than those of NR/PS composites and better than those of NR/SMK. The nitrogen permeability of NR/SMK composites was decreased by 20-40% after filling with kaolin. The significant improvements in the mechanical properties, thermal stability and gas barrier properties may be attributed to the parallel kaolinite particles which restricted the free movement of rubber chains and retarded the diffusion of the gas molecules. Thus, the highly filled NR/SMK composites may be used to improve the air-tightness of rubber products. © 2010 Elsevier B.V.


Wolbank T.M.,Vienna University of Technology | Nussbaumer P.,Vienna University of Technology | Chen H.,China University of Mining and Technology | MacHeiner P.E.,Elin EBG Traction
IEEE Transactions on Industrial Electronics | Year: 2011

Rotor-cage fault detection in inverter-fed induction machines is still difficult nowadays as the dynamics introduced by the control or load influence the fault-indicator signals commonly applied. In addition, detection is usually possible only when the machine is operated above a specific load level to generate a significant rotor-current magnitude. This paper proposes a new method of detecting rotor-bar defects at zero load and almost at standstill. The method uses the standard current sensors already present in modern industrial inverters and, hence, is noninvasive. It is thus well suited as a start-up test for drives. By applying an excitation with voltage pulses using the switching of the inverter and then measuring the resulting current slope, a new fault indicator is obtained. As a result, it is possible to clearly identify the fault-induced asymmetry in the machine's transient reactances. Although the transient-flux linkage cannot penetrate the rotor because of the cage, the faulty bar locally influences the zigzag flux, leading to a significant change in the transient reactances. Measurement results show the applicability and sensitivity of the proposed method. © 2010 IEEE.


Fan H.,China University of Mining and Technology | Liu X.,Wuhan University
Mathematical Methods in the Applied Sciences | Year: 2014

In this paper, we study the existence of multiple positive solutions for a degenerate nonlocal problem on unbounded domain. Using the Ekeland's variational principle combined with the mountain pass theorem, we show that problem admits at least two positive solutions under several different conditions. © 2014 John Wiley and Sons, Ltd.


Xu B.,Beijing Research Institute of Chemical Defense | Duan H.,China University of Mining and Technology | Chu M.,China University of Mining and Technology | Cao G.,Beijing Research Institute of Chemical Defense | Yang Y.,Beijing Research Institute of Chemical Defense
Journal of Materials Chemistry A | Year: 2013

A very simple, activation-free method for preparing nitrogen-doped porous carbon with high surface area for supercapacitors by direct pyrolysis of a nitrogen-containing organic salt, ethylenediamine tetraacetic acid (EDTA) disodium magnesium salt, in an inert atmosphere is presented. As the pyrolysis temperature increases from 500 to 900 °C, both the BET surface area and pore volume of the disodium magnesium EDTA-derived carbons increase and reach up to 1811 m2 g-1 and 1.16 cm3 g-1, respectively, while the nitrogen content decreases from 11.14 at.% to 1.13 at.%. The carbon obtained at a moderate pyrolysis temperature of 700 °C possesses a balanced surface area (1258 m2 g-1) and nitrogen content (5.43 at.%), exhibits high capacitance (281 F g-1), good rate capability (196 F g-1 at 20 A g-1) and cycle durability in 6 mol L-1 KOH aqueous electrolytes. This journal is © The Royal Society of Chemistry.


Xu B.,Beijing Research Institute of Chemical Defense | Hou S.,China University of Mining and Technology | Zhang F.,China University of Mining and Technology | Cao G.,Beijing Research Institute of Chemical Defense | And 2 more authors.
Journal of Electroanalytical Chemistry | Year: 2014

Nitrogen-doped mesoporous carbons were prepared using a biopolymer, gelatin as precursor by nano-CaCO3 template method. Although the surface area of the carbon obtained at 800 C is only 666 m2 g-1, the existence of abundant nitrogen-containing functional groups with a nitrogen content of 10.72 wt% makes the carbon has a relative high capacitance of 198 F g-1 in 6 mol L-1 KOH aqueous electrolytes. The developed mesoporous structure endows the carbon with good rate capability, and the capacitance can remain 135 F g-1 even when the current density increases to 20 A g-1. The carbon also possesses excellent cycle durability, indicating an attractive electrode material for supercapacitors. © 2013 Elsevier B.V. All rights reserved.


Yang C.,University of South Carolina | Yang Z.,University of South Carolina | Yang Z.,China University of Mining and Technology | Jin C.,Soochow University of China | And 3 more authors.
Advanced Materials | Year: 2012

A novel composite anode material consisting of K 2NiF 4-type structured Pr 0.8Sr 1.2(Co,Fe) 0.8Nb 0.2O 4+δ (K-PSCFN) matrix with homogenously dispersed nano-sized Co-Fe alloy (CFA) has been obtained by annealing perovskite Pr 0.4Sr 0.6Co 0.2Fe 0.7Nb 0.1O 3-δ (P-PSCFN) in H 2 at 900 °C. The K-PSCFN-CFA composite anode is redox-reversible and has demonstrated similar catalytic activity to Ni-based cermet anode, excellent sulfur tolerance, remarkable coking resistance and robust redox cyclability. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Zhang Y.,China University of Mining and Technology | Gong D.-W.,China University of Mining and Technology | Ding Z.,University of Nevada, Las Vegas
Information Sciences | Year: 2012

In this paper, we propose a new bare-bones multi-objective particle swarm optimization algorithm to solve the environmental/economic dispatch problems. The algorithm has three distinctive features: a particle updating strategy which does not require tuning up control parameters; a mutation operator with action range varying over time to expand the search capability; and an approach based on particle diversity to update the global particle leaders. Several trials have been carried out on the IEEE 30-bus test system. By comparing with seven existing multi-objective optimization algorithms and three well-known multi-objective particle swarm optimization techniques, it is found that our algorithm is capable of generating excellent approximation of the true Pareto front and can be used to solve other types of multi-objective optimization problems. © 2010 Elsevier Inc. All rights reserved.


Sun J.,China University of Mining and Technology | Su B.,China University of Mining and Technology | Su B.,Henan Polytechnic University
International Journal of Mining Science and Technology | Year: 2013

Based on the stability and inequality of texture features between coal and rock, this study used the digital image analysis technique to propose a coal-rock interface detection method. By using gray level co-occurrence matrix, twenty-two texture features were extracted from the images of coal and rock. Data dimension of the feature space reduced to four by feature selection, which was according to a separability criterion based on inter-class mean difference and within-class scatter. The experimental results show that the optimized features were effective in improving the separability of the samples and reducing the time complexity of the algorithm. In the optimized low-dimensional feature space, the coal-rock classifier was set up using the fisher discriminant method. Using the 10-fold cross-validation technique, the performance of the classifier was evaluated, and an average recognition rate of 94.12% was obtained. The results of comparative experiments show that the identification performance of the proposed method was superior to the texture description method based on gray histogram and gradient histogram. © 2013 Published by Elsevier B.V. on behalf of China University of Mining & Technology.


Liu X.R.,Xi'an Jiaotong University | Tian X.G.,Xi'an Jiaotong University | Lu T.J.,Xi'an Jiaotong University | Liang B.,China University of Mining and Technology
International Journal of Mechanical Sciences | Year: 2014

The dynamic responses and blast resistance of all-metallic sandwich plates with functionally graded close-celled aluminum foam cores are investigated using finite element simulations, and compared with those of ungraded single-layer sandwich plates. Upon validating the numerical approach using existing experimental data and introducing the present computational model, different graded sandwich plates under air blast loading are analyzed in terms of deformation and blast resistance. The effects of face-sheet arrangements and interfacial adhesion strength between different foam layers are quantified. The results demonstrate that relative to conventional ungraded plates subjected to identical air blast loading, the graded plates possess smaller central transverse deflection and superior blast resistance, with further improvement achievable by optimizing the foam core arrangement. The blast resistance of both graded and ungraded sandwich plates subjected to the constraint of equivalent mass is also explored. © 2014 Elsevier Ltd.


Fan H.,China University of Mining and Technology | Liu X.,Wuhan University
Mathematical Methods in the Applied Sciences | Year: 2014

In this paper, we study the multiplicity results of positive solutions for a semi-linear elliptic system involving critical growth terms. With the help of Nehari manifold and Ljusternik-Schnirelmann category, we investigate how the coefficient h(x) of the critical nonlinearity affects the number of positive solutions of that problem and get a relationship between the number of positive solutions and the topology of the global maximum set of h. © 2014 John Wiley and Sons, Ltd.


Xu B.,Beijing Research Institute of Chemical Defense | Hou S.,China University of Mining and Technology | Cao G.,Beijing Research Institute of Chemical Defense | Chu M.,China University of Mining and Technology | Yang Y.,Beijing Research Institute of Chemical Defense
RSC Advances | Year: 2013

High surface area, hierarchical porous carbons are easily prepared from poly(vinylidene fluoride) (PVDF) by NaOH activation. In contrast to the conventional two-step carbonization-activation method, we directly heated the mixture of powdery PVDF and NaOH at 600 °C to accomplish carbonization and activation in one step. In this process, NaOH acts as an interceptor of HF which comes from the PVDF decomposition, as well as an activation agent. SEM and TEM observation, along with nitrogen sorption measurements reveal that the carbons have a highly developed hierarchical porous structure containing interconnected micro-, meso-, and macropores. The specific surface area and pore volume of the carbon prepared at NaOH/PVDF = 3.5 reach values as high as 2711 m2 g-1 and 2.280 cm3 g-1, respectively. The unique hierarchical porous structure endows the carbon with a high capacitance and excellent rate capability in both aqueous and non-aqueous electrolytes. Its capacitance at a current load of 0.05 A g-1 reaches values as high as 339 F g-1 in 6 mol L-1 KOH and 162 F g-1 in 1 mol L-1 Et4NBF4/AN. The values still remain at 230 F g-1 and 98 F g-1, respectively, when the current load increases up to 20 A g-1. Combined with the simple preparation procedure, the present carbon may be a promising electrode material for supercapacitors. © 2013 The Royal Society of Chemistry.


Gao Z.-H.,China University of Mining and Technology | Zhang H.,Beijing Research Institute of Chemical Defense | Cao G.-P.,Beijing Research Institute of Chemical Defense | Han M.-F.,China University of Mining and Technology | And 2 more authors.
Electrochimica Acta | Year: 2013

In this work, the asymmetric supercapacitor in which spherical porous VN is used as a negative electrode and NiOx as a positive electrode was assembled in 1 M KOH aqueous electrolyte. The spherical porous VN negative material has a specific capacitance of 580 F/g and the NiOx positive electrode a specific capacitance of 680 F/g. The VN/NiOx symmetric supercapacitor shows a sloping voltage profile from 0.5 to 1.45 V with excellent reversibility and delivers a specific capacitance of 139 F/g and an energy density of 63 Wh/kg based on the total weight of the active electrode materials. The VN/NiOx asymmetric supercapacitor shows a good cycling behavior, about 15% specific capacitance decay after 1000 cycles. It also exhibits an excellent rate capability, even at a power density of 2400 W/kg, it has a specific energy 26 Wh/kg compared with 50 Wh/kg at the power density about 365 W/kg. © 2012 Elsevier Ltd.


Xiao T.,Henan Polytechnic University | Wang X.,China University of Mining and Technology | Zhang Z.,Shandong Xinjulong Energy Ltd Liability Company
International Journal of Mining Science and Technology | Year: 2014

In order to effectively control the deformation and failure of surrounding rocks in a coal roadway in a deep tectonic region, the deformation and failure mechanism and stability control mechanism were studied. With such methods as numerical simulation and field testing, the distribution law of the displacement, stress and plastic zone in the surrounding rocks was analyzed. The deformation and failure mechanisms of coal roadways in deep tectonic areas were revealed: under high tectonic stress, two sides will slide along the roof or floor; while the plastic zone of the two sides will extend along the roof or floor, leading to more serious deformation and failure in the corner of two sides and the bolt supporting the corners is readily cut off by the shear force or tension force. Aimed at controlling the large slippage deformation of the two sides, serious deformation and failure in the corners of the two sides and massive bolt breakage, a "controlling and yielding coupling support" control technology is proposed. Firstly, bolts which do not pass through the bedding plane should be used in the corners of the roadway, allowing the two sides to have some degree of sliding to achieve the purpose of "yielding" support, and which avoid breakage of the bolts in the corner. After yielding support, bolts in the corner of the roadway and which pass through the bedding plane should be used to control the deformation and failure of the coal in the corner. "Controlling and yielding coupling support" technology has been successfully applied in engineering practice, and the stability of deep coal roadway has been greatly improved. © 2014 Published by Elsevier B.V.


Kim D.-G.,Seoul National University | Mu S.,Seoul National University | Mu S.,China University of Mining and Technology | Kang S.,Kangwon National University | Lee D.,Seoul National University
Soil Biology and Biochemistry | Year: 2010

To better understand the factors that control forest soil CO2 efflux and the effects of rewetting on efflux, we measured soil CO2 efflux in adjacent deciduous, coniferous, and mixed forests in the central part of the Korean Peninsula over the course of one year. We also conducted laboratory rewetting experiments with soil collected from the three sites using three different incubation temperatures (4 °C, 10 °C, and 20 °C). Soil moisture (SM), soil organic matter (SOM), and total root mass values of the three sites were significantly different from one another; however, soil temperature (ST), observed soil CO2 efflux and sensitivity of soil CO2 efflux to ST (i.e., Q10 = 3.7 ± 0.1) were not significantly different among the three sites. Soil temperature was a dominant control factor regulating soil CO2 efflux during most of the year. We infer that soil CO2 efflux was not significantly different among the sites due to similar ST and Q10. Though a significant increase in soil CO2 efflux following rewetting of dry soil was observed both in the field observations (60-170%) and laboratory incubation experiments (100-1000%), both the increased rates of soil CO2 efflux and the magnitude of change in SM were not significantly different among the sites. The increased rates of soil CO2 efflux following rewetting depended on the initial SM before rewetting. During drying phase after rewetting, a significant correlation between SM and soil CO2 efflux was found, but the effect of ST on increased soil CO2 efflux was not clear. Cumulative peak soil CO2 efflux (11.3 ± 0.7 g CO2 m-2) following rewetting in the field was not significantly different among the sites. Those evidences indicate that the observed similar rewetting effects on soil CO2 efflux can be explained by the similar magnitude of change in SM after rewetting at the sites. We conclude that regardless of vegetation type, soil CO2 efflux and the effect of rewetting on soil CO2 efflux do not differ among the sites, and ST is a primary control factor for soil CO2 efflux while SM modulates the effect of rewetting on soil CO2 efflux. Further studies are needed to quantify and incorporate relationship of initial dryness of the soil and the frequency of the dry-wet cycle on soil CO2 efflux into models describing carbon (C) processes in forested ecosystems. © 2009 Elsevier Ltd. All rights reserved.


Meng Z.,China University of Mining and Technology | Meng Z.,China Three Gorges University | Li G.,Hubei University
Engineering Geology | Year: 2013

In order to investigate the permeability behavior of high rank coal during early depletion of CBM and its influencing factors, we collected 14 coal samples from Ordos Basin in northwest China and determined their air permeability under a varying effective stress of 2.5-20. MPa in laboratory. We used effective confining pressure to simulate effective stress. It turns out that high rank coal permeability is susceptible to effective stress. Permeability of coal samples declines exponentially with the rise of effective stress on the whole. When effective confining pressure variation ranges from 2.5. MPa to 10. MPa, permeability varies dramatically; when effective confining pressure rises to above 10. MPa, the curve of permeability decline gets gentle and the stress sensitivity becomes relatively weak. Coal permeability is also affected by coal moisture, maceral, fracturing and metamorphism degree. Permeability rises with the increase of vitrinite content and fracturing degree and decreases with the increase of moisture content. Permeability of wet and fractured coal samples is more sensitive to effective stress than dry intact ones and the irreversible permeability loss rate of fractured coal cores is significant, over 80%. Comparison of tests results of medium and low rank coal samples and high rank ones shows that, the stress sensitivity coefficient decreases with the increase of the maximum reflectance of vitrinite; if experiencing the same load-relief process, the irreversible permeability loss rate of low rank coal is less than that of medium and high rank coals. © 2013 Elsevier B.V.


Cheng G.,China University of Mining and Technology | Xu P.,China University of Mining and Technology | Yang D.,Nanjing Institute of Technology | Liu H.,China University of Mining and Technology
Robotics and Computer-Integrated Manufacturing | Year: 2013

In order to adjust the pose of mirror in segmented telescope initiatively, an active adjusting platform with a novel 3CPS PM as core module is proposed. It consists of a fixed base and a moving platform that is connected by three cylindrical-prismatic-spherical active legs. In this paper, the stiffness characteristics of the 3CPS PM with six DOF are studied systematically. First, the kinematics and statics are derived by the Rodrigues parameters method. Second, the stiffness matrix is proposed which is derived intuitively based on the principle of virtual work considering the compliances subject to both actuators and legs. Next, the elastic deformations of the moving platform corresponding to a given variation of pose parameters and external workload are analyzed. Moreover, applying a procedure iteratively over the workspace, the stiffness maps at initial height position are obtained. Finally, a FE model of the manipulator is constructed and the elastic deformations of FE model are basically coincident with that of analytic results. Both the analytical and FE results show that the stiffness characteristics of active adjusting platform satisfy the functional requirements of segmented telescope. © 2013 Elsevier Ltd.


Chen X.,Henan Polytechnic University | Cheng Y.,China University of Mining and Technology
Natural Hazards | Year: 2015

The measurement of the injecting water into coal is commonly used to prevent and control methane disasters, which will increase moisture in the coal, and the characteristics of methane desorption in coal will be changed. The methane desorption of different metamorphic degree coal was tested after injecting water on homemade device. The results show that the methane desorption quantity gradually decreased with the amount of injected water. The maximum effect was obtained from the DL coal (a decrease of 82.48 % after injecting water compared with the dry sample), and moderate effects were obtained from the QN coal and the YH coal, and the lowest effect was obtained from the GJZ coal (a decrease of 37.97–47.59 % after injecting water compared with the dry sample). The impact of the injected water on the methane desorption velocity is obvious in the first 40 min, and the methane diffusion coefficient decreases gradually with the amount of injected water. The injected water can reduce the gas outburst disasters by impacting on the methane desorption quantity, methane desorption velocity, and methane diffusion coefficient. © 2014, Springer Science+Business Media Dordrecht.


Liang Z.,China University of Mining and Technology | Li Y.,City University of Hong Kong | Zhao T.,University of Minnesota
Signal Processing | Year: 2010

Nonnegative matrix factorization (NMF) is a technique for analyzing the data structure when nonnegative constraints are imposed. However, NMF aims at minimizing the objective function from the viewpoint of data reconstruction and thus it may produce undesirable performances in classification tasks. In this paper, we develop a novel NMF algorithm (called KDNMF) by optimizing the objective function in a feature space under nonnegative constraints and discriminant constraints. The KDNMF method exploits the geometrical structure of data points and seeks the tradeoff between data reconstruction errors and the geometrical structure of data. The projected gradient method is used to solve KDNMF since directly using the multiplicative update algorithm to update nonnegative matrices is impractical for Gaussian kernels. Experiments on facial expression images and face images are conducted to show the effectiveness of the proposed method. © 2010 Elsevier B.V. All rights reserved.


Zhang Y.,China University of Mining and Technology | Zhang Y.,Shandong Institute of Business and Technology
Advances in Information Sciences and Service Sciences | Year: 2012

Based on the physical characteristic different impacting acoustic spectrum between coal and rock, a detection method for rock content in coal rock mixture in mechanized coal mining face was put forward by calculating and analyzing power spectrum of impacting acoustic data. Paper introduces the hardware and software design of embedded recognition system of coal and rock, algorithm and analysis of mixture content of coal and rock. After de-noising filtering, data spectrum and power spectrum analysis are carried out, the proportion of coal and rock is recognized. The acoustic detection method of coal rock-mix by analyzing is feasible and reliable.


Xu B.,Beijing Research Institute of Chemical Defense | Hou S.,China University of Mining and Technology | Chu M.,China University of Mining and Technology | Cao G.,Beijing Research Institute of Chemical Defense | Yang Y.,Beijing Research Institute of Chemical Defense
Carbon | Year: 2010

A simple method for the preparation of microporous carbon was presented by pyrolyzing poly(vinylidene fluoride) (PVDF) at high temperature under N 2 atmosphere without activation or any other additional processes. The yield of PVDF-derived carbon is 35.0%. Its specific surface area reaches 1012 m 2 g with a pore volume of 0.41 cm 3 g -1. The carbon is microporous with unimodal pore size distribution at 0.55 nm. © 2010 Elsevier Ltd. All rights reserved.


Wu B.,Fuzhou University | Zhang L.,Wuhan University | Zhao Y.,China University of Mining and Technology
IEEE Transactions on Geoscience and Remote Sensing | Year: 2014

A feature selection method based on Cramer's V-test (CV-test) discretization is presented to improve the classification accuracy of remotely sensed imagery. Three possible contributions are pursued in this paper. First of all, a Cramer's V-based discretization (CVD) algorithm is proposed to optimally partition the continuous features into discrete ones. Two association-based feature selection indexes, the CVD-based association index (CVDAI) and the class-attribution interdependence maximization (CAIM)-based association index (CAIMAI), derived from the CV-test value, are then proposed to select the optimal feature subset. Finally, the benefit of using discretized features to improve the performance with the J48 decision tree (J48-DT) and naive Bayes (NB) classifiers is studied. To validate the proposed approaches, a high spatial resolution image and two hyperspectral data sets were used to evaluate the performances of CVD and the associated algorithms. The test performances of discretization using CVD and two other state-of-the-art methods, the CAIM and equal width, show that the CVD-based technique has the better ability to generate a good discretization scheme. Furthermore, the feature selection indexes, CVDAI and CAIMAI, perform better than the other used feature selection methods in terms of overall accuracies achieved by the J48-DT, NB, and support vector machine classifiers. Our tests also show that the use of discretized features benefits the J48-DT and NB classifiers. © 1980-2012 IEEE.


Liu X.,Xi'an Jiaotong University | Tian X.,Xi'an Jiaotong University | Lu T.J.,Xi'an Jiaotong University | Zhou D.,Xi'an Jiaotong University | Liang B.,China University of Mining and Technology
Composite Structures | Year: 2012

The dynamic responses and blast resistance of all-metallic sandwich-walled hollow cylinders with graded aluminum foam cores are investigated using finite element simulations, and compared with those of conventional ungraded ones. After validating the numerical approach and introducing the computational model, sandwich-walled hollow cylinders with various graded aluminum foam cores are analyzed under air blast loading. It is demonstrated that the radial deflection of graded cylinders is smaller than and the blast resistance superior to that of ungraded ones when subjected to identical air blast loading. This can be further improved by optimizing the foam core arrangement. Finally, the influence of face-sheet arrangements on the dynamic behavior of graded cylinders is explored. © 2012 Elsevier Ltd.


Cheng G.,China University of Mining and Technology | Cheng Y.-L.,China University of Mining and Technology | Shen L.-H.,Tiandi Science And Technology | Qiu J.-B.,Tiandi Science And Technology | Zhang S.,China University of Mining and Technology
Measurement: Journal of the International Measurement Confederation | Year: 2013

Gear vibration signals always display non-stationary behavior. HHT (Hilbert-Huang transform) is a method for adaptive analysis of non-linear and non-stationary signals, but it can only distinguish conspicuous faults. SOM (self-organizing feature map) neural network is a network learning with no instructors which has self-adaptive and self-learning features and can compensate for the disadvantage of HHT. This paper proposed a new gear fault identification method based on HHT and SOM neural network. Firstly, the frequency families of gear vibration signals were separated effectively by EMD (empirical mode decomposition). Then Hilbert spectrum and Hilbert marginal spectrum were obtained by Hilbert transform of IMFs (intrinsic mode functions). The amplitude changes of gear vibration signals along with time and frequency had been displayed respectively. After HHT, the energy percentage of the first six IMFs were chosen as input vectors of SOM neural network for fault classification. The analysis results showed that the fault features of these signals can be accurately extracted and distinguished with the proposed approach. © 2012 Elsevier Ltd. All rights reserved.


Xu B.,Beijing Research Institute of Chemical Defense | Hou S.,China University of Mining and Technology | Duan H.,China University of Mining and Technology | Cao G.,Beijing Research Institute of Chemical Defense | And 2 more authors.
Journal of Power Sources | Year: 2013

Poly(vinylidene fluoride)-derived ultramicroporous carbon with a specific surface area of 1012 m2 g-1 and a very narrow pore-size distribution peaked at 0.55 nm is investigated as electrode material for supercapacitors. The unique microstructure features enable the carbon to present not only a high gravimetric capacitance (264 F g-1) but also a high electrode density (0.826 g cm-3), resulting in an outstanding high volumetric capacitance of 218 F cm-3 in 6 mol L-1 KOH aqueous electrolytes. However, the carbon shows a very small capacitance of less than 7 F g-1 in 1 mol L-1 Et4NBF 4/PC, which implies the pores are too small to be accessible even for the desolvated ions in the non-aqueous electrolyte. © 2012 Published by Elsevier B.V. All rights reserved.


Yi L.,China University of Mining and Technology | Zhang G.,CAS Academy of Opto Electronics | Wu Z.,Wuhan University
IEEE Transactions on Geoscience and Remote Sensing | Year: 2012

Multiscale segmentation is always needed to extract semantic meaningful objects for object-based remote sensing image analysis. Choosing the appropriate segmentation scales for distinct ground objects and intelligently combining them together are two crucial issues to get the appropriate segmentation result for target applications. With respect to these two issues, this paper proposes a simple scale-synthesis method which is highly flexible to be adjusted to meet the segmentation requirements of varying image-analysis tasks. The main idea of this method is to first divide the whole image area into multiple regions; each region consisted of ground objects that have similar optimal segmentation scale. Then, synthesize the suboptimal segmentations of each region to get the final segmentation result. The result is the combination of suboptimal scales of objects and is therefore more coherent to ground objects. To validate this method, the land-cover-category map is used to guide the scale synthesis of multiscale image segmentations for the Quickbird-image land-use classification. First, the image is coarsely divided into multiple regions; each region belongs to a certain land-cover category. Then, multiscale-segmentation results are generated by the Mumford-Shah function based region-merging method. For each land-cover category, the optimal segmentation scale is selected by the supervised segmentation-accuracy-assessment method. Finally, the optimal scales of segmentation results are synthesized under the guide of land-cover category. It is proved that the proposed scale-synthesis method can generate a more accurate segmentation result that benefits the latter classification. The land-use-classification accuracy reaches to 77.8%. © 2012 IEEE.


Yang S.-Q.,China University of Mining and Technology | Ni H.-M.,Henan University of Urban Construction
Zhongguo Kuangye Daxue Xuebao/Journal of China University of Mining and Technology | Year: 2012

A Burgers viscoelastic shear creep model is used to identify the creep parameters of mudstone. Experimental tests on mudstone were used to investigate the time scale effect on the model parameters. This model is not ideal for predicting long term deformation. The stationary creep stage was used to linearly fit the viscous coefficient, η 2, thereby allowing more accurate long term predictions. However, the Burgers model did not show good agreement with short time scale test results. The parameter, Q, from a nonlinear viscoelastic shear creep model range from 0.56 × 10 -8 to 1.49 × 10 -8, which is lower than the 0.16 × 10 -8 to 8.15 × 10 -8 obtained from the Burgers shear creep model. Hence, nonlinear viscoelastic shear creep provides better agreement with the experimental results than the Burgers shear creep model for long term creep deformation predictions.


Niu S.,Henan Polytechnic University | Jing H.,China University of Mining and Technology | Yang D.,Henan Polytechnic University
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2012

In the engineering background of a failure deep mine roadways of in Shandong Yuncheng Mine, its excavation unloading whole process is physically simulated by the large scale (1.0 m× 1.0 m× 1.0 m) three-dimension test system. The failure patterns and range of surrounding rock of deep mine roadways with no support are obtained by the method of model thin section. Using the independent development testing elements for three-dimensional stress, the actual loading-unloading stress paths and stress states of surrounding rock in different depths of deep mine roadways are revealed, and the evolution law of deviatoric stress inside and outside of the broken rock zone are mainly studied. Based on the results of the failure patterns and range of surrounding rock, the evolution mechanism of deviatoric stress is initial explored.


Cheng L.,CAS Institute of Atmospheric Physics | Zhu J.,CAS Institute of Atmospheric Physics | Reseghetti F.,New Energy Technologies | Liu Q.,China University of Mining and Technology
Journal of Atmospheric and Oceanic Technology | Year: 2011

A new technique to estimate three major biases of XBT probes (improper fall rate, start-up transient, and pure temperature error) has been developed. Different from the well-known and standard "temperature error free" differential method, the new method analyses temperature profiles instead of vertical gradient temperature profiles. Consequently, it seems to be more noise resistant because it uses the integral property over the entire vertical profile instead of gradients. Its validity and robustness have been checked in two ways. In the first case, the new integral technique and the standard differential method have been applied to a set of simulated XBT profiles having a known fall-rate equation to which various combinations of pure temperature errors, random errors, and spikes have been added for the sake of this simulation. Results indicated that the single pure temperature error has little impact on the fall-rate coefficients for both methods, whereas with the added random error and spikes the simulation leads to better results with the new integral technique than with the standard differential method. In the second case, two sets of profiles from actual XBT versus CTD comparisons, collected near Barbados in 1990 and in the western Mediterranean (2003-04 and 2008-09), have been used. The individual fall-rate coefficients and start-up transient for each XBT profile, along with the overall pure temperature correction, have been calculated for the XBT profiles. To standardize procedures and to improve the terms of comparison, the individual start-up transient estimated by the integral method was also assigned and included in calculations with the differential method. The new integral method significantly reduces both the temperature difference between XBT and CTD profiles and the standard deviation. Finally, the validity of the mean fall-rate coefficients and the mean start-up transient, respectively, for DB and T7 probes as precalculated equations was verified. In this case, the temperature difference is reduced to less than 0.1°C for both datasets, and it randomly distributes around the null value. In addition, the standard deviation on depth values is largely reduced, and the maximum depth error computed with the datasets near Barbados is within 1.1% of its real value. Results also indicate that the integral method has a good performance mainly when applied to profiles in regions with either a very large temperature gradient, at the thermocline or a very small one, toward the bottom. © 2011 American Meteorological Society.


Liu C.-M.,Xuzhou Normal University | Ma J.-Q.,China University of Mining and Technology | Sun Y.-Z.,Xuzhou Normal University
Experimental and Toxicologic Pathology | Year: 2012

Puerarin (PU), a natural flavonoid, has been reported to have many benefits and medicinal properties. In this study, we valuated the protective effect of puerarin against lead-induced oxidative DNA damage and apoptosis in rat liver. A total of forty male Wistar rats (8-week-old) was divided into 4 groups: control group; lead-treated group (500. mg Pb/l as the only drinking fluid); lead. +. puerarin treated group (500. mg Pb/l as the only drinking fluid plus 400. mg PU/kg. bwt intra-gastrically once daily); and puerarin-treated group (400. mg PU/kg. bwt intra-gastrically once daily). The experimental period was lasted for 75 successive days. Our data showed that puerarin significantly effectively improved the lead-induced histology changes in rat liver and decreased the serum ALT and AST activities in lead-treated rats. Puerarin markedly restored Cu/Zn-SOD, CAT and GPx activities and the GSH/GSSG ratio in the liver of lead-treated rat. Furthermore, the increase of 8-hydroxydeoxyguanosine induced by lead was effectively suppressed by puerarin. The enhanced caspase-3 activity in the rat liver induced by lead was also inhibited by puerarin. TUNEL assay showed that lead-induced apoptosis in rat liver was significantly inhibited by puerarin, which might be attributed to its antioxidant property. In conclusion, these results suggested that puerarin could protect the rat liver against lead-induced injury by reducing ROS production, renewing the activities of antioxidant enzymes and decreasing DNA oxidative damage. © 2010.


Zhang B.,China University of Mining and Technology | Chen Z.M.,Renmin University of China | Xia X.H.,Renmin University of China | Xu X.Y.,China University of Mining and Technology | Chen Y.B.,Renmin University of China
Energy Policy | Year: 2013

To systematically reveal how domestic trade impacts on China's regional energy uses, an interprovincial input-output modeling is carried out to address demand-derived energy requirements for the regional economies in 2007 based on the recently available data. Both the energy uses embodied in final demand and interregional trade are investigated from the regional and sectoral insights. Significant net transfers of embodied energy flows are identified from the central and western areas to the eastern area via interregional trade. Shanxi is the largest energy producer and interregional embodied energy deficit receiver, in contrast to Guangdong as the largest energy user and surplus receiver. By considering the impacts of interregional trade, the energy uses of most eastern regions increase remarkably. For instance, Shanghai, Hainan, Zhejiang, Beijing, Jiangsu and Guangdong have their embodied energy requirements 87.49, 19.97, 13.64, 12.60, 6.46 and 6.38 times of their direct energy inputs, respectively. In contrast, the embodied energy uses of some central and western regions such as Inner Mongolia, Shanxi, Xinjiang, Shaanxi and Guizhou decrease largely. The results help understand the hidden network linkages of interregional embodied energy flows and provide critical insight to amend China's current end-reduction-oriented energy policies by addressing the problem of regional responsibility transfer. © 2013 Elsevier Ltd.


Zhu J.B.,Ecole Polytechnique Federale de Lausanne | Zhao G.F.,University of New South Wales | Zhao G.F.,China University of Mining and Technology | Zhao X.B.,Nanjing University | Zhao J.,Ecole Polytechnique Federale de Lausanne
Computers and Geotechnics | Year: 2011

A validation study of the distinct lattice spring model (DLSM) for wave propagation problems is performed. DLSM is a microstructure-based numerical model, which is meshless and has advantages in modelling dynamic problems where stress wave propagation is important. To verify the applicability of DLSM to modelling wave propagation through a discontinuous medium, the virtual wave source (VWS) method is used to obtain analytical solutions for wave propagation across a jointed rock mass. Numerical modelling results of the commercial code UDEC are selected as the reference. The effects of particle size and lattice rotation angle on wave propagation are first studied. Then, the results of wave transmission across a single joint with a different joint stiffness and across multiple parallel joints with different joint spacings are derived with DLSM, UDEC and VWS. These results are in good agreement with each other. Therefore, the capability of DLSM to model P-wave propagation across jointed rock mass is verified, which provides confidence for the further application of DLSM to modelling more complex problems. © 2010 Elsevier Ltd.


Hower J.C.,University of Kentucky | Dai S.,China University of Mining and Technology
Fuel | Year: 2016

Sized samples of anthracite were obtained from three preparation plants (breakers), several beneficiating multiple coals, in the Pennsylvania Anthracite Fields. Vitrinite reflectance spans 5.07% Rmax (anthracite, approaching meta-anthracite) in the east to 2.36% Rmax (semi-anthracite) in the west. Maceral distributions do not show the size partitioning observed in many bituminous coals. All sites showed distinct Gd anomalies, possibly a function of hydrothermal metamorphism of the coals. The rare earth distribution pattern (L-, M-, and H-type) within the products from each breaker are similar. Principal components analysis confirmed an observation from the latter assessment that coals from the same breaker tend to cluster together, but distinct from the clusters of the other breakers. © 2016 Elsevier Ltd


Liu C.-M.,Xuzhou Normal University | Ma J.-Q.,China University of Mining and Technology | Sun Y.-Z.,Xuzhou Normal University
Food and Chemical Toxicology | Year: 2011

Puerarin (PU), a natural flavonoid, has been reported to have many benefits and medicinal properties. The aim of the present study was to investigate the effects of puerarin on hepatic oxidative stress and hyperlipidemia in rats exposed to lead. Our data showed that puerarin significantly prevented lead-induced hepatotoxicity, indicated by both diagnostic indicators of liver damage (serum aminotransferase levels) and histopathological analysis. Moreover, lead-induced profound elevation of ROS production and oxidative stress, as evidenced by increasing of lipid peroxidation level, reducing of GPx, GST, GR and GCL activities and depleting of intracellular reduced GSH level in liver, were suppressed by treatment with puerarin. Furthermore, the increase of serum cholesterol, triglycerides and LDL induced by lead was effectively suppressed by puerarin. The HDL level in the lead treatment rats was also increased by puerarin. Western blot analysis showed that puerarin remarkably inhibited hyperlipidemia by regulating the expression of cholesterol 7a-hydroxylase (CYP7A1), 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) and low-density lipoprotein receptor (LDL-R) in liver of lead treated rats. Altogether, these results suggest that puerarin could protect the lead-induced liver injury and hyperlipidemia by reducing ROS production, renewing the activities of antioxidant enzymes and influencing expression of hepatic lipid biosynthesis and metabolism genes. © 2011 Elsevier Ltd.


Sun Y.,Hebei University of Engineering | Qin S.,Hebei University of Engineering | Qin S.,China University of Mining and Technology | Zhao C.,Hebei University of Engineering | Kalkreuth W.,Federal University of Rio Grande do Sul
Energy and Fuels | Year: 2010

To study the early formation processes of macerals and sulfides, 12 samples were simulated in a constant temperature box with low temperature (80 °C). Coniferaes were used as organic matter, and gypsum, metals, and salts were used as catalysts in this experiment. The samples have been simulated for four years in the box. The variation of the organic matter was observed every year by microscopy. The results indicate that the liptinite and huminite macerals formed in a very short time (less than one year). Some framboidal sulfides formed before one year, and some crystal sulfides occurred before two years. Copyright © 2010 American Chemical Society.


Lu J.,Xuzhou Normal University | Wu D.-M.,Xuzhou Normal University | Wu D.-M.,China University of Mining and Technology | Zheng Y.-L.,Xuzhou Normal University | And 2 more authors.
Brain Pathology | Year: 2010

Purple sweet potato color (PSPC), a class of naturally occurring anthocyanins, protects brain function against oxidative stress induced by D-galactose (D-gal) (Sigma-Aldrich, St. Louis, MO, USA). Our data showed that PSPC enhanced open-field activity, decreased step-through latency, and improved spatial learning and memory ability in D-gal-treated old mice by decreasing advanced glycation end-products' (AGEs) formation and the AGE receptor (RAGE) expression, and by elevating Cu,Zn-superoxide dismutase (Cu,Zn-SOD) (Sigma-Aldrich) and catalase (CAT) expression and activity. Cleavage of caspase-3 and increased terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick-end-labeling (TUNEL)-positive cells in D-gal-treated old mice were inhibited by PSPC, which might be attributed to its antioxidant property. PSPC also suppressed the activation of c-Jun NH 2-terminal kinase (JNK) and the release of cytochrome c from mitochondria that counteracted the onset of neuronal apoptosis in D-gal-treated old mice. Furthermore, it was demonstrated that phosphoinositide 3-kinase (PI3K) activation was required for PSPC to promote the neuronal survival accompanied with phosphorylation and activation of Akt and p44/42 mitogen-activated protein kinase (MAPK) by using PI3K inhibitor LY294002 (Cell Signaling Technology, Inc., Beverly, MA, USA), implicating a neuronal survival mechanism. The present results suggest that neuronal survival promoted by PSPC may be a potentially effective method to enhance resistance of neurons to age-related disease. © 2009 International Society of Neuropathology.


Wang K.,Beijing Institute of Technology | Lu B.,China University of Mining and Technology | Wei Y.-M.,Beijing Institute of Technology
Applied Energy | Year: 2013

Energy and environmental efficiency evaluation has recently attracted increasing interest in China. In this study, we utilize the Range-Adjusted Measure (RAM) based nonparametric approach to evaluate the regional energy and environmental efficiency of China over the period of 2006-2010. The desirable/good and undesirable/bad outputs, as well as the energy and non-energy inputs are considered in the efficiency evaluation so as to characterize the energy consumption, economic production, and CO2 emission process of different China's regions. In addition, the economic concepts of natural disposability and managerial disposability are incorporated in the evaluation instead of the strong and weak disposability in conventional environmental efficiency evaluation. Therefore, the types of returns to scale and damages to scale of different China's regions are measured and correspondingly the strategy and policy implications are proposed for guiding the future improvement of regional energy and environmental efficiency. This study finds that: (i) Beijing, Shanghai, and Guangdong had the highest integrated energy and environmental efficiency during the study period, which could be seen as the benchmarks of inefficient China's regions. (ii) On average, east China had the highest integrated efficiency under natural disposability, and west China had the highest integrated efficiency under managerial disposability. (iii) During 2006-2010, the average production efficiency of China slightly decreased and the average emission efficiency of China slightly increased. (iv) Among China's 30 regions, 19 regions exhibited decreasing returns to scale, 4 regions shown increasing returns to scale, and 7 regions have mixed returns to scale types under natural disposability in our study period. In addition, under managerial disposability, there are 18, 3 and 9 regions respectively exhibited increasing, decreasing and mixed damages to scale types over time. (v) For most Chinese regions, it is not recommended to simply increase or maintain their current scales of production, but alternatively, they should pay more attentions on technology innovation of energy utilization efficiency improvement, since up to 2010, China still had large energy conservation and emission reduction potentials. © 2013 Elsevier Ltd.


Liu J.,China University of Mining and Technology | Pham T.D.,University of New South Wales
Pattern Recognition | Year: 2012

We present in this paper a fuzzy clustering algorithm which can handle spatially constraint problems often encountered in pattern recognition. The proposed method is based on the notions of hyperplanes, the fuzzy c-means, and spatial constraints. By adding a spatial regularizer into the fuzzy hyperplane-based objective function, the proposed method can take into account additionally important information of inherently spatial data. Experimental results have demonstrated that the proposed algorithm achieves superior results to some other popular fuzzy clustering models, and has potential for cluster analysis in spatial domain. © 2011 Elsevier Ltd All rights reserved.


Liu C.-M.,Xuzhou Normal University | Ma J.-Q.,China University of Mining and Technology | Sun Y.-Z.,Xuzhou Normal University
Environmental Toxicology and Pharmacology | Year: 2010

Quercetin, a flavonoid, effectively improved the lead-induced histology changes including structure damage and leukocyte infiltration in rat kidney. The present study was designed to explore the protective mechanism of quercetin against lead-induced oxidative DNA damage and apoptosis in rat kidney. We found that quercetin markedly decreased the ROS level and lowered the GSH/GSSG ratio in the kidney of lead-treated rat. The increase of 8-hydroxydeoxyguanosine level in the kidney of lead-treated rat was effectively suppressed by quercetin. Furthermore, quercetin markedly restored Cu/Zn-SOD, CAT and GPx activities in the kidney of lead-treated rat. TUNEL assay showed that lead-induced apoptosis in rat kidney was significantly inhibited by quercetin, which might be attributed to its antioxidant property. In conclusion, these results suggested that quercetin could protect the rat kidney against lead-induced injury by improving renal function, attenuating histopathologic changes, reducing ROS production, renewing the activities of antioxidant enzymes, decreasing DNA oxidative damage and apoptosis. © 2010 Elsevier B.V.


Miao X.,China University of Mining and Technology | Li S.,Xuzhou Normal University | Chen Z.,China University of Mining and Technology | Liu W.,China University of Mining and Technology
Transport in Porous Media | Year: 2011

In coal mining the water flow in broken rock is a very common phenomenon. Study of seepage properties of broken rock is one of the basic subjects required in order to understand the stability of rock surrounding roadways, preventing disasters such as water inrush and gas outbursts and developing underground resources. So far, quantitative studies on the nonlinear seepage properties of broken sandstone under different porosities are not extensive in the research literature. In this article, by means of an electro-hydraulic servo-controlled test system (MTS815. 02) and a patent seepage device, the seepage properties under different conditions of porosity were tested on broken sandstone of five different grain sizes. Based on the loading method of controlling the axial compression displacement and steady permeating method, we obtained curves of the relation of pore pressure with time, as well as the relation curves between the pore pressure gradient for steady seepage and velocity. Furthermore, we calculated the permeability k and non-Darcy coefficient β corresponding to different porosities by fitting these curves with the binomial expression. This study indicates that: (1) the seepage properties of broken sandstone are closely related to grain size, load levels, and porosity structure; (2) the permeability k decreases, while the coefficient β increases with a decrease in porosity φ, but both the k - φ and the β - φ curves show some local fluctuations; (3) the permeability k of the broken sandstone has a magnitude of 10-14-10-12 m2, while the coefficient β ranges from 1010 to 1012 m-1. The results obtained provide some information for further study of the nonlinear seepage behavior of broken rock theoretically. © 2010 Springer Science+Business Media B.V.


Mao Z.,China University of Mining and Technology | Zheng Y.-L.,Xuzhou Normal University | Zhang Y.-Q.,China University of Mining and Technology
International Journal of Molecular Sciences | Year: 2011

Nonylphenol (NP) is a degradation product of nonylphenol polyethoxylates, which are widely used in the production of industrial and consumer surfactants. The aim of the present study was to evaluate the effect of NP on the antioxidant capacity and cognitive ability of mice. NP was given orally by gavages at doses of 0, 50, 100, and 200 mg kg -1 d -1 for 90 days. The results showed that NP significantly decreased the activity of superoxide dismutases (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) and at the same time increased malondialdehyde (MDA) levels in mice brains. Exploration, memory function and ability to learn a novel task were significantly decreased in NP fed mice. These results indicate that chronic high dose of NP exposure has the potential to generate oxidative stress and induce the cognitive impairment in male mice. © 2010 by the authors; licensee MDPI, Basel, Switzerland.


Zhang B.,China University of Mining and Technology | Qiao H.,University of Chinese Academy of Sciences | Chen Z.M.,Renmin University of China | Chen B.,King Abdulaziz University
Applied Energy | Year: 2015

This paper investigates the temporal and spatial changes of embodied energy transfers via China's domestic trade over 2002-2007 based on the multi-regional input-output models. Interregional trade of total embodied energy uses approximately tripled between 2002 and 2007, and the total trade volumes in it were equivalent to 38.2% of the national total direct primary energy input in 2002 and 62.9% of that in 2007, respectively. Among all the eight regions, Northwest, Central, Northeast and Southwest were the interregional net exporters and deficit receivers of embodied energy in contrast to East Coast, South Coast, North Coast and Beijing-Tianjin as interregional net importers and surplus receivers. Significant growth of net embodied energy transfers can be identified from central and western inland regions to eastern coastal regions, and the Central region partly served as a "transmission channel". By considering the interregional embodied energy transfers, regional energy use inventories changed largely, and the spatial and temporal differences between 2002 and 2007 were expanding. Industrial positions in domestic and global supply chains and inherent economic driving factors such as increasing regional consumption level, accelerated investment in fixed assets and rapidly expanding export were the major driving forces for the embodied energy transfers among regions. To form a set of useful tool for controlling energy consumption and achieving the goals for energy saving and emission reduction, China's governors at all levels deserve to understand the relationships between energy producers and users from the view of demand-driven energy requirements. © 2015 Elsevier Ltd.


Wang D.,China University of Mining and Technology | Nie R.,China University of Mining and Technology | Shi H.-Y.,China University of Mining and Technology | Shi H.-Y.,Xuzhou Normal University
Energy Procedia | Year: 2011

Based on the policies of economic, energy and environment, the IPAT model is applied to analyze the scenarios of China's future primary energy demand and CO2 emissions. The results show that: primary energy demands and CO2 emissions will grow rapidly before 2020, due to the impact of the industrialization. The LCS scenario's primary energy demand reach 4.48 billion tce and CO2 emission 10.58 billion tons in 2020, which are far less than those in scenario-BUS; the goals of CO2 emission reduction and energy structure optimization are at the cost of slowing economic growth to some extent in scenario-LCS. The aggregate GDP has decreased by 8.26 trillion yuan compared to that in scenario-BUS; there are great scenario differences in energy demand structure. The expected energy structure would be achieved in scenario-LCS, as the share of coal slowly decreases and its physical quantity reaches 3.76 billion tons, and the non-fossil energies' structure amounts to 15.95%; The scenario of LCS is a realistic choice to low carbon economy. The keys of the energy saving and energy structure optimization are the clean utilization of coal and development of new energy on a large scale. © 2011 Published by Elsevier Ltd.


Cao J.-P.,Gunma University | Cao J.-P.,China University of Mining and Technology | Li L.-Y.,Gunma University | Morishita K.,Gunma University | And 4 more authors.
Fuel | Year: 2013

Fast pyrolysis of a sewage sludge sample, which contains a high content of nitrogen, was investigated to understand the effects of pyrolysis temperature and sweeping gas flow rate on the yields of pyrolysis products and the distributions of carbon and nitrogen. The maximum oil yield of ca. 48.7% (daf) was achieved at a pyrolysis temperature of 500 °C and a sweeping gas flow rate of 600 cm3/min. NH3 was found to be the predominant nitrogenous gas under all the conditions, and its yield increased with raising pyrolysis temperature and decreasing sweeping gas flow rate. The significant release of NH3 at temperatures lower than 500 °C should be related to the high protein content in the sludge. The N yield in HCN was lower than 2% during pyrolysis below 550 °C, and sharply increased to 5.8% at 700 °C due to thermal cracking of volatile matter. Water-insoluble nitrogen- and carbon-containing species were significantly decomposed to water-soluble ones during secondary reactions. At high temperatures, heavy hydrocarbons were mainly cracked to gaseous products, while the nitrogen-containing species tended to form water-soluble species. This study provides a basic insight into the nitrogen transformations during fast pyrolysis of sludge, which would benefit the clean utilization of sludge as an energy source. © 2010 Elsevier Ltd. All rights reserved.


Liu J.-C.,China University of Mining and Technology | Zhang Q.-G.,Luoyang Normal University
CMES - Computer Modeling in Engineering and Sciences | Year: 2013

In this paper, we propose an algorithm to solve a Cauchy problem of the Laplace equation in doubly connected domains for 2D and 3D cases in which the Cauchy data are given on the outer boundary. We want to seek a solution in the form of the single-layer potential and discrete it by parametrization to yield an ill-conditioned system of algebraic equations. Then we apply the Tikhonov regularization method to solve this ill-posed problem and obtain a stable numerical solution. Based on the regularization parameter chosen suitably by GCV criterion, the proposed method can get the approximate temperature and heat flux on the inner boundary. Numerical examples illustrate that the proposed method is reasonable and feasible. Copyright © 2013 Tech Science Press.


Wang H.,China University of Mining and Technology | Cheng Y.,China University of Mining and Technology | Yuan L.,Huainan Mining Industry Group Ltd Liability Company
Natural Hazards | Year: 2013

Coal and gas outburst disasters in coal seams are becoming more serious as coal mines extend deeper underground in China. To aid gas control in high-gas outburst coal seam group, this study performed research based on the geological conditions of the Xinzhuangzi coal mine in the Huainan coalfield. The laws of gas occurrence, the strength of the coal outburst, and the regional partition were studied. Simultaneously, we introduced the key protective seam mining technology and confirmed the mining sequence of coal seam groups. The results indicate that (1) each seam absorbs gas well, and the currently measured gas content is up to 15. 0 m3/t. (2) Although some differences about coal seams outburst intensity remain, the differences in the same group are very small. (3) The coal seam B10 was chosen as the key protective seam and was mined first; then adjacent seams were mined from bottom to top by layer within the roof of B10 and from top-to-bottom within the floor of B10 to guarantee each adjacent coal seam received the good effects of pressure-relief and increasing permeability. (4) The main methods of gas extraction in each protected seam are surface boreholes and net-like penetrating boreholes in the floor roadway, and related technical parameters were determined according to the degree of pressure-relief in coal seam. This in situ experiment indicates a method aiding the gas control problem and guaranteeing safe and highly efficient exploitation of high-gas outburst seams. © 2013 Springer Science+Business Media Dordrecht.


Liu C.-M.,Xuzhou Normal University | Ma J.-Q.,China University of Mining and Technology | Lou Y.,China University of Mining and Technology
Food and Chemical Toxicology | Year: 2010

Troxerutin, a natural bioflavonoid, has been reported to have many benefits and medicinal properties. In this study, we evaluated the protective effect of troxerutin against d-gal-induced oxidative DNA damage in mouse kidney, and explored the potential mechanism of its action. Our data showed that troxerutin significantly decreased levels of urea, uric acid and creatinine in serum and the renal histological injury in d-gal-treated mice. Troxerutin markedly restored Cu/Zn-SOD, CAT and GPx activities in the kidney of d-gal-treated mouse. Furthermore, the increase of 8-hydroxydeoxyguanosine (a marker of oxidative DNA damage) induced by d-gal was effectively suppressed by troxerutin. Internucleosomal DNA ladder fragmentation and the number of terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick-end-labeling (TUNEL)-positive cells in d-gal-treated mice were inhibited by troxerutin, which might be attributed to its antioxidant property by decreasing activities of nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase) and levels of reactive oxygen species (ROS). In conclusion, these results suggested that troxerutin could protect the mouse kidney against d-gal-induced injury by improving renal function, attenuating histopathologic changes, reducing ROS production, renewing the activities of antioxidant enzymes and decreasing DNA oxidative damage. This study provided novel insights into the protective mechanisms of troxerutin in d-gal-induced kidney injury. © 2010 Elsevier Ltd.


Chen H.,China University of Mining and Technology | Lu S.,Nanjing Institute of Electronics
IEEE Transactions on Industrial Electronics | Year: 2013

This paper describes four main fault types of the asymmetric bridge power converter in switched reluctance motor drive on power transistors. Two on-line fault diagnosis methods for power transistors in the power converter are proposed. The principle of the proposed diagnosis methods is to detect the real-time current state from some particular positions, and then obtain the diagnosis result and the fault location by logical judgment. One fault diagnosis method is proposed using single current sensor monitoring the chopped bus current; the other method is using dual current sensors scheme monitoring the upper freewheeling bus current and excitation bus current. The simulation results of current states from certain positions of a three-phase 12/8 motor and its power converter are analyzed. Experiments have verified the effectiveness of the proposed fault diagnosis methods. It is shown that the dual current sensors scheme monitoring the upper freewheeling bus current and excitation bus current has the fastest fault response. © 2012 IEEE.


Huang G.,China University of Mining and Technology | Chen F.,University of Hong Kong | Chen F.,South China University of Technology | Wei D.,South China University of Technology | And 2 more authors.
Applied Energy | Year: 2010

Biodiesel has received much attention in recent years. Although numerous reports are available on the production of biodiesel from vegetable oils of terraneous oil-plants, such as soybean, sunflower and palm oils, the production of biodiesel from microalgae is a newly emerging field. Microalgal biotechnology appears to possess high potential for biodiesel production because a significant increase in lipid content of microalgae is now possible through heterotrophic cultivation and genetic engineering approaches. This paper provides an overview of the technologies in the production of biodiesel from microalgae, including the various modes of cultivation for the production of oil-rich microalgal biomass, as well as the subsequent downstream processing for biodiesel production. The advances and prospects of using microalgal biotechnology for biodiesel production are discussed. © 2009 Elsevier Ltd. All rights reserved.


Zhao Y.,China University of Mining and Technology | Zhao G.-F.,University of New South Wales | Jiang Y.,China University of Mining and Technology
International Journal of Fracture | Year: 2013

In this paper, fracturing in coal under impact loads was studied using experimental and numerical approaches. Three-point beam bending tests were carried out on coal samples under impact loads. During the testing, cracking velocity in the samples was captured using a multi-spark high-speed photography system. Characteristics of the fracture surface were investigated using the scanning electron microscopy, 3D laser surface topography scanner and X-ray micro Computed Tomography (X-ray micro-CT). Differences between the fracture surface under impact loads and that in quasi-static test were analysed. Moreover, discrete numerical modelling was conducted to assess the influence of impact velocity, heterogeneity, and grain size on dynamic fracturing in coal. Based on observations from the testing and numerical simulation, it was concluded that the influence of heterogeneity and grain size was more pronounced in dynamic fracturing comparing to that under quasi-static loading. © 2013 Springer Science+Business Media Dordrecht.


Dong H.-M.,China University of Mining and Technology
Wuli Xuebao/Acta Physica Sinica | Year: 2013

In this paper, we present a detailed theoretical study of nonlinear terahertz optical properties of graphene in the presence of electric field and terahertz radiation field. The optical current is computed and investigated on the basis of quantum theory and semi-classical Boltzmann equations. It shows a large nonlinear terahertz response and the nonlinearity becomes larger with increasing electric field or decreasing terahertz frequencies. Moreover, it is found that the optical nonlinearity can be modified and controlled by electric fields. © 2013 Chinese Physical Society.


Dong H.-M.,China University of Mining and Technology
Wuli Xuebao/Acta Physica Sinica | Year: 2013

The two-dimensional, single-layer MoS2 with a direct band-gap of 1.8 eV, which makes it very suitable for nanoelectronic applications, such as field-effect transistors, has aroused great interest because of its distinctive electronic, optical, and catalytic properties. In this paper, we present a detailed theoretical study of the electronic transport property of single-layer MoS2 on the basis of the usual momentum-balance equation. We obtain the analytical electric mobility at low temperature. It shows that the electric mobility of MoS2 is linear with respect to substrate dielectric constant squared and the rate between the electron density and charged impurity density at low temperature. It is found that by using relatively high dielectric constant materials as substrates, reducing impurity densities and increasing carrier densities high mobilities in MoS2-substrate wafer systems can be achieved. © 2013 Chinese Physical Society.


Yan X.,China University of Mining and Technology | Li X.,China University of Petroleum - East China | Yan Z.,China University of Petroleum - East China | Komarneni S.,Pennsylvania State University
Applied Surface Science | Year: 2014

Three porous carbons were prepared by direct carbonization of HKUST-1, MOF-5 and Al-PCP without additional carbon precursors. The carbon samples obtained by carbonization at 1073 K were characterized by XRD, TEM and N 2 physisorption techniques followed by testing for electrochemical performance. The BET surface areas of the three carbons were in the range of 50-1103 m2/g. As electrode materials for supercapacitor, the MOF-5 and Al-PCP derived carbons displayed the ideal capacitor behavior, whereas the HKUST-1 derived carbon showed poor capacitive behavior at various sweep rates and current densities. Among those carbon samples, Al-PCP derived carbons exhibited highest specific capacitance (232.8 F/g) in 30% KOH solution at the current density of 100 mA/g. © 2014 Elsevier B.V.


Liang Y.,China University of Mining and Technology | Yu D.-S.,China University of Mining and Technology | Chen H.,China University of Mining and Technology
Wuli Xuebao/Acta Physica Sinica | Year: 2013

Meminductor, a nonlinear device with memory ability and controllable meminductance, was generalized on the basis of the conception of memristor. Currently, meminductor is still unavailable on the market. Therefore, in order to investigate its properties and potential application, designing electronic emulator is of significant importance. In this paper, a flux-controlled memristive emulator using ligh-dependent resistor (LDR) is proposed and the mutator for transferring memristor into a flux controlled meminductor is described, of which the realization is on the basis of two current conveyor chips and operational amplifiers. Results of Pspice simulation and hardware experiments indicate that the current-flux characteristic of the meminductor is a frequency-dependent pinched loop, like an inclined number "8". To confirm the effectiveness and correctness, the proposed emulator is analyzed theoretically and tested experimentally as it is connected in an RLMC series circuit. The dynamic behaviors of the RLMC circuit are analyzed and observed. All the results manifest that this newly proposed emulator is capable of simulating a nonlinear meminductor and can be applied to the analog circuit design. © Chinese Physical Society.


Du F.,China University of Mining and Technology | Bai H.-B.,China University of Mining and Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2012

Based on the methods of numerical simulation, theoretical analysis, field measurement and so on, the breakage mechanism of overlying strata of ultrathin bedrock and thick coal seam and mining-induced development were studied. The results indicate that with the weathering, mechanical property of ultrathin bedrock substantially reduces, there are key overburden in coal roof, stress arch is in dynamical balance by mining, and apsidal angle is located in gangue of worked out section and coal wall in front of working face, underground pressure of working face is not obvious with the influence of stress arch; stress arch prevents the growth of the fracture during mining, the growth of the fracture during mining depends on the final height of the stress arch, fracture grows quickly and closes easily, although the height is gigantic, valid water-guiding crack does not grow high finally. The research result properly explains the phenomenon of big static pressure, little dynamic pressure, little coefficient of live load, insufficiency of fracture growing and so on under conditions of fully-mechanized top-coal caving mining with ultrathin bedrock and thick coal seam, made safe and efficient production come true under conditions of fully-mechanized top-coal caving mining with ultrathin bedrock and thick coal seam.


Ju J.-F.,China University of Mining and Technology | Xu J.-L.,China University of Mining and Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2012

Aiming at the problem of the strong strata behaviors during the working face out of the upper dip coal pillar in contiguous seams, adopted theoretical analysis, numerical simulation and engineering verification from the view of the instability in the upper coal pillar boundary occurring ahead of the face described the inhibitory mechanism that results in strong strata behavior disasters, and studied the influence law of the leading instability in coal pillar boundary that affected by buried depth of coal pillar, with or without key strata between coal seams, with or without abandoned roadway in coal pillar boundary and others. The results show that when the working face closes to push-out of the upper dip coal pillar, the reverted turning in upper key blocks will take place in advance, which caused by the instability of coal pillar boundary in advance, so weakening the energy generated when key block structure make turning motion on strata between the seams and eventually weakening the possibility and intensity of strong strata behavior disasters. Great depth of the upper dip coal pillar, without key strata between coal seams and abandoned roadway existed in the dip coal pillar boundary are easily led to instability in coal pillar boundary occurring ahead, thus which will play a significant inhibition on the occurrence of strong strata behavior disasters. For the mining conditions of the shallow buried depth of coal seams or only one key strata existing in coal seams which easy to lead the strong strata behavior disasters, we can dig abandoned roadways within the boundary of the coal pillar which is corresponding to the side of the under working face out of the pillar or carry out artificial pre-blasting in this area, which cause the coal pillar boundary occurring instability in advance at the time of working face close to out of the pillar and so as to get the purpose of controlling mine disasters of strong strata behavior. The results are verified with mining engineering projects in four working faces of Huojitu & Bulianta Coal Mine in Shendong mining area.


Wang D.,China University of Mining and Technology | Sui W.,China University of Mining and Technology
International Journal of Mining Science and Technology | Year: 2012

The deep, loose bottom aquifer of the eastern air shaft in the Xinglongzhuang Coal Mine was used to develop an experimental model of shaft grouting through Model deep soil. Lab experiments using chemical grouting were done to study the grout. The grouted soil shapes and osmotic pressure were measured during the experiments. The tested characteristics of the grouted soil show that the diffusion mode of grout in saturated sandy soil is a combination of split compaction and osmosis. More specifically, the shape of the grouted soil is determined by split compaction while the size of the grouted soil shape is determined by osmosis. Sensor test results indicate that the main reason for the non-uniform grout diffusion is the anisotropic osmotic pressure field surrounding the grouting holes. © 2012 Published by Elsevier B.V. on behalf of China University of Mining and Technology.


Guo J.-W.,China University of Mining and Technology | Guo J.-W.,Energy Chemical Industry Research Institute
Meitan Xuebao/Journal of the China Coal Society | Year: 2012

Aimed at the stability of surrounding rock in Pingdingshan Coal Mine, took a typical deep roadway with joint fissured surrounding rock as study object, used discrete element numerical simulation, simulated the deformation and failure mechanism of surrounding rock, and the control technologies of joint fissured surrounding rock roadway were proposed. The results show that the tensile failure appears at vault and two side-walls and in the middle of floor at first. Then, the shear failure appears at spandrel and two base angles. The failure zone extends into the deep area until the roadway is instable. According to the in-situ monitor data, it is concluded that the stress in anchor and cable tends to be stable after supporting for two months, as well as the horizontal convergence, vault subsidence and floor heave. It means that the supporting technology works and the stability of soft surrounding rock in deep rock roadway is controlled.


Li L.,China University of Mining and Technology | Bai J.-B.,China University of Mining and Technology | Wang X.-Y.,China University of Mining and Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2012

By using of theoretical analysis method, the structural mechanical model of roadway driving along next goaf was established, and the width expression of internal stress fields was derived, the rational position of roadway driving along next goaf was determined and the deformation of the surrounding rock was also calculated. Meanwhile, the parameter of roadway was given. At last, the control technology of roadway driving along next goaf in thick seam was put forward, and the first is high strength and pretension bolt supporting to control roof, the second is decreasing bolt interval of roadway gob-side, the last is secondary supporting to the integrated coal side of roadway, based on this, the bolt supporting parameter was determined by system information design method, and it is successfully applied to engineering practile.


Zhou F.-B.,China University of Mining and Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2012

The investigation of gas and coal spontaneous combustion in 229 coal mines of main mining areas in China shows that 74 mines suffer from the coexistence of gas and spontaneous combustion of coal, the number of which has a increasing trend with the mining depth growing. So the coal disaster mechanism caused by the coexistence of gas and spontaneous combustion was studied, which proved that disasters arise only from the intersection area of CH 4, O 2 and heat in cracks. What's more, the mathematical model of multi-gas migrating in cracks was built upon definite data, establishing the relationship between mass concentration and velocity of gases such as N 2, O 2 and CH 4. At last, typical disaster cases in coal mines was analyzed to verify the practicability of disaster mechanism of gas and coal spontaneous combustion coexistence.


Xu J.-L.,China University of Mining and Technology | Zhu W.-B.,China University of Mining and Technology | Wang X.-Z.,China University of Mining and Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2012

Based on depth study of the influence law of key strata on the height of fractured water-conducting zone, this paper proposed a new method to predict the height of fractured water-conducting zone by location of key strata. The engineering measurements and theoretical research results show that the key stratum location affects the height of fractured water-conducting zone in the roof, when the distance from key stratum to the coal seam is less than a critical value, the fracture of key stratum will develop to water-conducting fracture, and the same goes to the fracture of the overlying strata controlled by key stratum leading to a synchronous breakage with key stratum. The critical height of key stratum fracture can be roughly estimated to be (7~10)M, where M is coal mining height. When it is less than (7~10)M from the primary key stratum to coal seam, water-conducting fracture will grow to the location above the roof of the bed rock, then the height of fractured water-conducting zone is equal to or greater than the height of the bed rock. When the distance from the primary key stratum to coal seam is greater than (7~10)M, water-conducting fracture in the roof will develop to the position below the nearest key stratum being (7~10)M more away from the coal seam, and then the height of fractured water-conducting zone equals to the distance of the key stratum to coal seam. The prediction method is able to predict the height of fractured water-conducting zone in the roof with different mining heights, meanwhile, it also can be utilized to distinguish the abnormal development of the height of fractured water-conducting zone induced by structural changes of key stratum, and its reliability is verified by engineering measurements results.


Wang W.,China University of Mining and Technology | Wang Y.,China University of Mining and Technology | Shi G.,China University of Mining and Technology
Optics Express | Year: 2015

The optical radiation and radiation transfer characteristics of atmospheric particulate matter (PM) in mining area of northwest China were simulated and analyzed in this paper. Computational fluid dynamics (CFD) method was adopted to simulate the distribution of PM considering the local desertification and mining activities. The 1-D radiative transfer equation was solved using discrete ordinates method combined with Mie scattering model based on the CFD simulation results. The spectral aerosol optical depth and transmission characteristics of PM polluted atmosphere in the wavelength of 1-25μm under different intensity of dust releases, wind speeds and dust compositions were obtained and analyzed. The simulation results show that: the transmission characteristics are obviously enhanced with the increase of wind speed and sand particles' proportion but greatly decreased with the increase of the intensity of dust release. © 2015 Optical Society of America.


Zhou L.-G.,China University of Mining and Technology | Wu C.-F.,China University of Mining and Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2012

Through a series of relevant experiments of coal samples in main coal seams of study area, analyzed the variation of the pore characteristics and porosity characterization parameters, discussed the geological factors which control pore characteristics. The results show that the pore can be divided into four big types in main coal seams of Bide-Santang basin. Porosity is range from 4.06% to 10.12%. Micropore and minipore takes the dominant position, and provides more than 80% of the total pore volume. The mercury withdrawal efficiency is high. Pore forms are mainly open, contains a number of semi-closed pore. Pore surface area is 18-21 m2/g, micropore occupies the highest proportion. Pore tortuosity has significant impact on threshold pressure. Median pore diameter of volume are mostly around 10 nm, the average of median pore diameter of area is 4.58 nm. Porosity and pore volume show "U" shape tendency with the increase of coal rank, with Ro, max=2.0% as the cut-off point. The content of vitrinite is more than 70% in general control the amount of micropore and minipore. While the increase of minerals' content has negative impact on the development of pore system.


Haifeng W.,China University of Mining and Technology | Yuanping C.,China University of Mining and Technology | Lei W.,China University of Mining and Technology
International Journal of Mining Science and Technology | Year: 2012

China's rapid economic development has increased the demand for coal. These results in Chinese coal mines being extended to deeper levels. The eastern Chinese, more economical developed, regions have a long history of coal mining and many coal mines have now started deep mining at a depth from 800 to 1500 m. This increase in mining depth, geostresses, pressures, and gas content of the coal seam complicates geologic construction conditions. Lower permeability and softer coal contribute to increasing numbers of coal and gas outburst, and gas explosion, disasters. A search on effective methods of preventing gas disasters has been provided funds from the Chinese government since 1998. The National Engineering Research Center of Coal Gas Control and the Huainan and Huaibei Mining Group have conducted theoretical and experimental research on a regional gas extraction technology. The results included two important findings. First, grouped coal seams allow adoption of a method where a first, key protective layer is mined to protect upper and lower coal seams by increasing permeability from 400 to 3000 times. Desorption of gas and gas extraction in the protected coal seam of up to 60%, or more, may be achieved in this way. Second, a single seam may be protected by using a dense network of extraction boreholes consisting of cross and along-bed holes. Combined with this is increased use of water that increases extraction of coal seam gas by up to 50%. Engineering practice showed that regional gas drainage technology eliminates regional coal and gas outburst and also enables mining under low gas conditions. These research results have been adopted into the national safety codes of production technology. This paper systematically introduces the principles of the technology, the engineering methods and techniques, and the parameters of regional gas drainage. Engineering applications are discussed. © 2012 Published by Elsevier B.V. on behalf of China University of Mining and Technology.


Gao W.-J.,North China Institute of Science and Technology | Shan R.-L.,China University of Mining and Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2012

The experiments performed on split Hopkinson pressure bar(SHPB)with a large diameter show that the anthracite has a threshold speed 4.3 m/s under impact loading. The threshold value provided the number basis of reference in order to improve anthracite coal lump ratio, and reform the optimization of production system and storage transportation system. Based on the characteristics of measured dynamic curves, anthracite is of distinct plastic yield and strengthen properties, and the initial elastic modulus, yield strength, as well as the ultimate strength go up with strain rate; but there is the best correlation between yield strength and the strain rate. Anthracite failure under impact loading is classified into four patterns: compress-shearing damage, tensile stress damage, extensible strain damage and unloading damage, among them, tensile stress destruction, tensile strain damage and uninstall damage are the main destroy forms.


Ma Q.,China University of Mining and Technology
Beijing Ligong Daxue Xuebao/Transaction of Beijing Institute of Technology | Year: 2011

With the decrease of gas pressure in cleat, changes occur in the absolute permeability of coal-bed methane (CBM) reservoirs during primary depletion. To investigate this variation, based on the volumetric balance among the factors of bulk coal, solid grains and pores, how the MATCHSTICK strain changes with pore pressure is studied in this paper first. Furthermore, how permeability varies with the strain changes is researched and then the regularity of permeability changes is proposed. The rationality of applying MATCHSTICK strain changes to analyze permeability is proved by the curves of strain and permeability changes obtained from production field and laboratory.


Tian Y.,China University of Mining and Technology | Qin Z.,China University of Mining and Technology | Li B.,China University of Mining and Technology
International Journal of Mining Science and Technology | Year: 2012

Tongting coal (TTC) was exhaustively extracted with carbon disulfide and N-melthy-2-pyrolidinone (CS 2/NMP) mixed solvents to afford brown particles of extract, which was characterized with proximate analyzer, transmission electron microscope (TEM) and Fourier transform infrared (FTIR) spectrometer. The results show that the nanometer particles of extract, which were free of ash, are superfine and super-clean with tract content of 0.02% A d and particles size of about 100-150 nm. TTC and extract were then subject to oxidation with H 2O 2 and oxidation products were subsequently analyzed with FTIR and gas chromatography/mass spectrometer (GC/MS). The results show that extract is more reactive with H 2O 2 in comparison to TTC and richer in oxygen-containing species including phenols, alcohols, ethers, esters, carboxylic acids and anhydrides. © 2012 Published by Elsevier B.V. on behalf of China University of Mining & Technology.


Wang J.-L.,China University of Mining and Technology | Qin Y.,China University of Mining and Technology | Fu X.-H.,China University of Mining and Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2012

The primary influential factors of coal reservoirs permeability were analyzed, and the basic theoretic problems about viscid seepage of coal reservoirs were discussed. In different conditions of axial compression, confining pressure and pressure gradient of gas, the seepage CH 4 experiments of some anthracite samples, which were picked from Jincheng mining area, Shanxi Province, were carried out in three-dimensional stress field. It was calculated and analyzed the factors of effective stress, coal matrix shrinkage and slippage effect of gas affect permeability, and how the actions of superimposition behave. It is considered that the boundary layer consists of molecules of CH 4 in adsorption state when gas permeating in pore-fissure of coal reservoirs. The slippage effect occurs out of the boundary layer. The dynamic changes of the coal reservoirs permeability are the superimposition of such influential factors as effective stress, coal matrix shrinkage and slippage effect. The permeability attenuates observably as the pressure gradient from 0 to 0.1 MPa. The magnitude of contribution what slippage effect does for permeability is far less than coal matrix shrinkage effect. The effect of slippage may be ignored when pressure gradient increases.


Miao X.-X.,China University of Mining and Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2012

On the basis of a brief overview of mining with backfilling history and the objectives, requirements and difficulties of developing modern mining with backfilling technology, this paper systematically introduced the research progress of fully mechanized mining with solid backfilling technology, focused on the expounding the strata movement theory of mining with dense backfilling, including equivalent mining height theory of strata movement control, continuous media mechanics model of strata movement, calculation formula of strata movement, and stope rock pressure and support stress analysis, which are the prerequisites of the new technology. And then detailedly introduced the system, equipments and technics of fully mechanized mining with solid backfilling technology, and the engineering examples of large-scale mining with backfilling under dense buildings, island village coal pillar, near the loosen aquifer and under the large embankment.


Xu D.-J.,China University of Mining and Technology
Caikuang yu Anquan Gongcheng Xuebao/Journal of Mining and Safety Engineering | Year: 2011

To prevent water burst from floor in the first mining district of Wolong coalmine, the geological and mechanical model of the study area is built on the basis of analyzing geological characteristics of coal seam floor, lithology with magmatic rocks and their combined characteristics, and adopting the constitutive relation of strain softening. In addition, the watery and the hydraulic pressure for limestone aquifer of Taiyuan formation are investigated. The mining effect of coal seam floor over the confined water are numerically analyzed by fast Lagrangian analysis of continua and the failure depth of the coal seam floor are identified by analyzing their stress and displacement fields in the first mining district. The results show that the depth of fractured zone is 13 m and is not beyond the critical value established by the water inrush coefficient. In other words, there is not any risk of water inrush during the mining of NO.10 coal seam.


Xie F.,China University of Mining and Technology | Hou Y.,China University of Mining and Technology
Mining Science and Technology | Year: 2010

To show the distribution of a temperature field on a steel disk and to prolong the service life of a friction pair in a Hydro-Viscous Drive (HVD) device, a theoretical model of a transient temperature field was established, based on the theory of heat conduction. This theoretical model was solved using a finite element method. The results show that the surface temperature of the steel disk does not increase consistently as a function of the radius; the highest temperature appears short of the maximum radius. The relationship between the surface temperature and the mixed friction time is exponential. With a friction time of 15 s, the temperature reached 465.9 °C. Simultaneously, the internal thermal stress is larger than the yield stress of the material, causing a warping deformation of the steel disk. The largest axial deformation is 0.32 mm. The results of the experiment suggest that the deformation is the same as that obtained from numerical simulation. Therefore, deformation of the steel disk must be considered during the study of the characteristics of a HVD. © 2010 China University of Mining and Technology.


Wang Z.,China University of Mining and Technology
Lecture Notes in Electrical Engineering | Year: 2015

The development framework is the basic and core software resource which can provide a general and reusable structure among all the software applications. This paper proposes a rapid development framework (RDF) of enterprise information system based on software components and JavaEE, the paper not only describes the framework’s structure and the detailed functions of each parts in RDF, but also gives an application example. The development practice proves that this framework has good maintainability, extendibility and stability, it can meet the development needs of most software applications. © Springer-Verlag Berlin Heidelberg 2015.


Liang Y.,China University of Mining and Technology | Chen H.,China University of Mining and Technology | Yu D.S.,China University of Mining and Technology
IEEE Transactions on Circuits and Systems II: Express Briefs | Year: 2014

A meminductor, a nonlinear two-terminal device with memory and energy storage ability, is generalized on the basis of the conception of a memristor. To date, the meminductor is commonly unavailable; therefore, it is of great significance to build a meminductor emulator in hardware. In this brief, a practical floating flux-controlled meminductor emulator is designed without using a memristor. Moreover, it possesses floating terminals and a variable structure that allow the designers to alter the nonlinear flux-controlled function only via utilization of fewer electronic components. Frequency-dependent current-flux dynamics of this meminductor have been captured in the experiment, which convincingly confirms the validity of this emulator. Finally, the experimental errors existing in the hardware circuit are analyzed. All the analysis results manifest that this newly proposed floating emulator can be operated as a floating meminductor and applied in the analog circuit design. © 2004-2012 IEEE.


Yang S.-Q.,China University of Mining and Technology | Huang Y.-H.,China University of Mining and Technology
Acta Mechanica Sinica/Lixue Xuebao | Year: 2014

A discrete element method (DEM) called particle flow code (PFC 2D) was used to construct a model for Brazilian disc splitting test in the present study. Based on the experimental results of intact Brazilian disc of rock-like material, a set of micro-parameters in PFC2D that reflected the macro-mechanical behavior of rock-like materials were obtained. And then PFC2D was used to simulate Brazilian splitting test for jointed rock mass specimens and specimen containing a central straight notch. The effect of joint angle and notch angle on the tensile strength and failure mode of jointed rock specimens was detailed analyzed. In order to reveal the meso-mechanical mechanism of crack coalescence, displacement trend lines were applied to analyze the displacement evolution during the crack initiation and propagation. The investigated conclusions can be described as follows. (1) The tensile strength of jointed rock mass disc specimen is dependent to the joint angle. As the joint angle increases, the tensile strength of jointed rock specimen takes on a nonlinear variance. (2) The tensile strength of jointed rock mass disc specimen containing a central straight notch distributes as a function of both joint angle and notch angle. (3) Three major failure modes, i.e., pure tensile failure, shear failure and mixed tension and shear failure mode are observed in jointed rock mass disc specimens under Brazilian test. (4) The notch angle and joint angle play important roles on crack initiation and propagation characteristics of jointed rock mass disc specimen containing a central straight notch under Brazilian test. © 2014 The Chinese Society of Theoretical and Applied Mechanics; Institute of Mechanics, Chinese Academy of Sciences and Springer-Verlag Berlin Heidelberg.


He M.-C.,China University of Mining and Technology | Zhao J.,China University of Mining and Technology
Chinese Physics Letters | Year: 2012

Density functional theory is used to investigate the adsorption, diffusion, and dissociation of H 2O on kaolinite(001) surface. It is found that the preferred adsorption sites on the kaolinite(001) surface for H 2O are the threefold hollow sites with the adsorption energies ranging from 1.06 to 1.15 eV. H 2O does not adsorb on the six-fold hollow site of the aluminium(001) face of the third layer of kaolinite, implying that it is difficult for water molecules to penetrate the ideal kaolinite(001) surface. In addition, we calculate the energetic barriers for the diffusion of H 2O between the most stable and next most stable adsorption sites, which range from 0.073 to 0.129eV. The results also show that H 2O molecules are easy to diffuse on kaolinite(001) surface. Finally, our study indicates that no dissociation state exists for the H 2O on kaolinite(001) surface. © 2012 Chinese Physical Society and IOP Publishing Ltd.


Zhu S.,China University of Mining and Technology | Zhu S.,Huazhong University of Science and Technology | Shen Y.,Huazhong University of Science and Technology
Neurocomputing | Year: 2011

In this paper, the problem of passivity analysis is investigated for a class of stochastic delayed neural networks with Markovian switching. By applying Lyapunov functional and free-weighting matrix, delay-dependent/independent passivity criteria are presented in terms of linear matrix inequalities. The results herein include existing ones for neural networks without Markovian switching as special cases. An example is given to demonstrate the effectiveness of the proposed criteria. © 2011 Elsevier B.V.


Jing W.,China University of Mining and Technology | Tan G.,China University of Mining and Technology | Ye Z.,China University of Mining and Technology
Diangong Jishu Xuebao/Transactions of China Electrotechnical Society | Year: 2011

Thermal design of the converter can be optimized if the power losses are precisely known. The device's conduction and switching characteristics are very sensitive to the temperatures, so the influence of junction temperatures must be taken into consideration when calculating the power losses. In this paper, a practical loss calculation method is derived based on the analysis of the conduction and switching principles of the neutral point clamping three-level converters. Using thermal resistance equivalent circuit, the devices junction temperatures are acquired. An 1MVA NPC converter is tested in inverter and rectifier operating modes, and the infrared thermal imager is used to measure the devices temperatures. The error rates between measured and calculated temperatures are within 5% range and thus the validity of the loss calculation method is verified.


Xu J.-L.,China University of Mining and Technology | Zhu W.-B.,China University of Mining and Technology | Wang X.-Z.,China University of Mining and Technology
Caikuang yu Anquan Gongcheng Xuebao/Journal of Mining and Safety Engineering | Year: 2011

According to the several water inrush disasters in Qidong coal mine, we adopt field measurements and simulation experiments in this paper, to study the development characteristics of water flowing fracture, water inrush mechanism, prediction of water inrush zone, and prevention strategy, et al, while mining under the unconsolidated confined aquifer. The results show that the support crushing accident appeared before each water inrush in Qidong coal mine, which proves that it exist close relationship between water inrush accident and overburden moment. Due to the effect of load transfer of the unconsolidated confined aquifer, the adjacent key strata are prone to compound breakage, which can cause the bedrock broken as a whole in a wide range below the unconsolidated confined aquifer. Therefore, the height of water flowing fractured zone becomes obviously larger and then communicates the unconsolidated confined aquifer. This is the fundamental reason for the abnormal water inrush disaster when mining under the unconsolidated confined aquifer. Finally, prediction method to determine water inrush zone and the prevention strategy were put forward here, which guided the water inrush prevention effectively when mining under the unconsolidated confined aquifer in Qidong coal mine.


Zhang H.-L.,China University of Mining and Technology | Wang L.-G.,China University of Mining and Technology
Caikuang yu Anquan Gongcheng Xuebao/Journal of Mining and Safety Engineering | Year: 2011

In order to study the stress distribution and deformation law of the floor after the coal seam is excavated, using the elastic theory in the form of increment, we obtain the additional vertical stress, horizontal stress, and shear stress of any point through the MATHCAD software. The distribution map of additional stress of the floor is drawn. According to Mohr-Coulomb criterion, the additional stress is converted to principal stress, then the failure depth of the floor is predicted with the introduction of the rock strength index and the failure depth of 1022 working face in Taoyuan coal mine is in-situ tested with the hydraulic test method. The results show that the additional concentrated stress near the coal wall decreases gradually with the increase of the depth of floor, and the failure depth of the floor computed is 12% different from that obtained in the in-situ test, showing a high reliability of the theoretical computation. The results in this paper can provide a theoretical basis for the control of water-inrush in the coal mining under pressure.


Yang S.-Q.,China University of Mining and Technology | Liu X.-R.,China University of Mining and Technology
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2012

Based on the obtained volumetric-axial strain curves of marble with pre-existing fissures under different confining pressures, the effect of confining pressures on dilatancy behavior of marble with pre-existing fissures is analyzed. The results show that the crack damage thresholds of intact and pre-cracked marble all increase linearly with the confining pressures, and that the sensibility of the crack damage thresholds to the confining pressures is lower than that to the peak strength. Under the same confining pressure, the medium marble with smaller grain sizes has higher crack damage threshold. The long-term internal friction angles of intact and pre-cracked marble are lower distinctly than the short-term, but the reducing extent of long-term cohesion is closely related to fissure geometry. The higher the peak strength of intact or pre-cracked marble, the larger the corresponding crack damage thresholds. The peak strength of intact and pre-cracked marble has a good linear relation with the crack damage thresholds. The conclusions are significant for the choice of mechanical parameters of rock mass with jointed fissures when carrying out engineering design and numerical simulation.


Li H.,Dalian University of Technology | Mu H.,Dalian University of Technology | Zhang M.,China University of Mining and Technology | Li N.,Dalian University of Technology
Energy Policy | Year: 2011

With the intensification of global warming and continued growth in energy consumption, China is facing increasing pressure to cut its CO2 (carbon dioxide) emissions down. This paper discusses the driving forces influencing China's CO2 emissions based on Path-STIRPAT model-a method combining Path analysis with STIRPAT (stochastic impacts by regression on population, affluence and technology) model. The analysis shows that GDP per capita (A), industrial structure (IS), population (P), urbanization level (R) and technology level (T) are the main factors influencing China's CO2 emissions, which exert an influence interactively and collaboratively. The sequence of the size of factors' direct influence on China's CO2 emission is A>T>P>R>IS, while that of factors' total influence is A>R>P>T>IS. One percent increase in A, IS, P, R and T leads to 0.44, 1.58, 1.31, 1.12 and -1.09 percentage change in CO2 emission totally, where their direct contribution is 0.45, 0.07, 0.63, 0.08, 0.92, respectively. Improving T is the most important way for CO2 reduction in China. © 2011 Elsevier Ltd.


Long J.,China University of Mining and Technology
Caikuang yu Anquan Gongcheng Xuebao/Journal of Mining and Safety Engineering | Year: 2016

In response to the difficulties during the surrounding rock control in deep roadway, based on previous research and engineering practices, the mechanism of synergetic anchorage in deep roadway surrounding rock has been put forward, taking synergetics as its theoretical basis and guideline. Through analyzing the components of the controlling system of the roadway surrounding rock, and introducing the way how synergetics direct the anchorage of surrounding rocks, a research framework has been built to propose the synergetic mechanisms concerning structure, intensity, rigidity, anchorage timing, preload, and deformation. The study shows that the synergetic anchorage system achieves the effect of 1+1>2, as its macroscale function outweighs the sum of its total subsystems. This is of fundamental and vital importance to the stability control of the deep roadway surrounding rock, and meets the essential needs of safety production of coal. © 2016, China University of Mining and Technology. All right reserved.


Chen S.,China University of Mining and Technology | Zhu Y.,China University of Mining and Technology | Wang H.,Petrochina | Liu H.,Petrochina | And 2 more authors.
Energy | Year: 2011

The Lower Silurian Longmaxi Formation is an organic-rich (black) mudrock that is widely considered to be a potential shale gas reservoir in the southern Sichuan Basin (the Yangtze plate) in Southwest China. A case study is presented to characterise the shale gas reservoir using a workflow to evaluate its characteristics. A typical characterisation of a gas shale reservoir was determined using basset sample analysis (geochemical, petrographical, mineralogical, and petrophysical) through a series of tests. The results show that the Lower Silurian Longmaxi Formation shale reservoir is characterised by organic geochemistry and mineralogical, petrophysical and gas adsorption. Analysis of the data demonstrates that the reservoir properties of the rock in this region are rich and that the bottom group of the Longmaxi Formation has the greatest potential for gas production due to higher thermal maturity, total organic carbon (TOC) enrichment, better porosity and improved fracture potential. These results will provide a basis for further evaluation of the hydrocarbon potential of the Longmaxi Formation shale in the Sichuan Basin and for identifying areas with exploration potential. © 2011 Elsevier Ltd.


Chen S.-Z.,China University of Mining and Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2012

Based on the need of mobile crusher semi-continuous mining system application in large open pit mines, this dissertation comprehensively applied surface mining theories, mining engineering system theories, technology economics theories, as well as computer technology. Through investigation researches, theoretical analysis and spot engineering practice, the dissertation researched on crushing equipment selection, structure optimization, determination of crusher locations and shifting distance, as well as the application of stripping semi-continuous technology system. Based on the results of previous studies, the dissertation summarized the classification of crusher and the concepts of all kinds crushers in this dissertation. With the aim of open pit profit maximization, this study established a two-grade crusher comprehensive optimization model. In addition, according to the needs of stripping semi-continuous technology system used in open pit coal mine, the crushing characteristics and suitable crusher type of the high moisture content and easily bond material were analyzed. This dissertation present a view of modular crusher station as well as to improve the flexibility, reliability, and local production ratio of the crusher station, and to improve the working environment. Based on these, the dissertation established the parameter optimization model of feed hopper structure. This dissertation showed the previous research results on truck-shovel match of shovel truck discontinuance technology system, and analyzed the characteristic of truck transport under mobile crusher station semi-continuous mining system. Targeting the lowest system production cost the dissertation established the optimization model of truck type. According to the characteristics of mobile crusher locate in pit, this dissertation analyzed the affect factors and established the optimization model of crusher station location optimization model and shifting distance optimization model. The dissertation also introduced the transport distance increase coefficient k into the optimization model to embody the influence of belt conveyor transport system of the lower level to the internal dumping distance of upper levels. According to the need of stripping semi-continuous technology system application and the characteristics of mobile crusher, the dissertation established service areas model of open pits semi-continuous mining system, group bench mining model and strip width optimization model in this dissertation. These models provided the basis for service areas and mining parameters determination of stripping semi-continuous technology system. In order to meet the needs of stripping semi-continuous technology system application with mountain slope dumping area, system characteristics, link structure, application conditions and economic efficiency of discontinuous-continuous-discontinuous form semi-continuous technology system were analyzed in this dissertation. In order to improve the belt conveyer efficiency, the dissertation presented combined system that crusher and bucket wheel excavator use the same transport system, and four kinds crusher station location have been compared. The author verified the practicality of models established in this dissertation through case studies.


Xu L.-J.,China University of Mining and Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2012

In order to investigate crushing degree of coal-gangue with different roller structure by squirrelcage selectivity sepatation equipment, a discrete element model was established with particle flow code in two dimensions(PFC 2D) based on soft ball model, and dynamic behaviors of coal-gangue particles were simulated and analysed with different roller structures. The result shows that crushing degree of coal-gangue is moderate with 6 broken rods. Coal-gangue can not break with 9 broken rods, and coal-gangue may severely break with 3 broken rods. It is shown by the comparisons between numerical results and experimental data that they have good consistency.


Meng Z.-P.,China Three Gorges University | Meng Z.-P.,China University of Mining and Technology | Hou Q.-L.,University of Chinese Academy of Sciences
Meitan Xuebao/Journal of the China Coal Society | Year: 2012

Adopted samples from the high-rank coal reservoirs in Southeast margin of Ordos Basin, through the stress sensitivity experiment of coal samples, stress sensitivity of coal reservoirs and the effects of effective confining pressure, fractures inside the coal and water condition on stress sensitivity were analyzed. The results show that, the permeability decreases according to negative exponential function with the increase of effective stress. When effective stress changes from 2.5 MPa to 10 MPa, dimensionless permeability of the coal samples is 0.10~0.28, and the average value is less than 0.15; the damage rates of permeability are 71.92%~90.14%, and the average value is 84.59%. When effective stress is less than 5 MPa, the coal reservoir permeability decreases rapidly with the increase of the effective stress, the stress sensitivity is the highest; when effective stress is between 5 MPa and 10 MPa, the stress sensitivity is medium; when effective stress bigger than 10 MPa, the decline of the permeability slow down, and the stress sensitivity is weak. The initial permeability of coal samples with fractures inside is higher, and the stress sensitivity is relatively small; the irreversible plastic deformation generated larger in the lifting-pressure process results in relatively high irreversible damage rates after the pressure decreas. The permeability of wet coal samples reduces rapidly with the increase of effective pressure, with the increase of moisture content, the stress sensitivity is more obvious.


Liu S.-G.,China University of Mining and Technology | Hu A.-M.,Petrochina | Song B.,Petrochina | Li H.-F.,China University of Mining and Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2012

In order to solve the problem of coal powder interference in coalbed methane(CBM) well drainage, which causes gas production fluctuation even stuck pump frequently, the source and form mechanism of coal powder were analyzed. Based on the monitoring data of CBM well in Ordos Basin, the coal powder concentration warning index was presented. Sieve tube were used to avoid large particle get into pump, and water were injected from tubing-casing annular space to dilute coal powder concentration. The field application results demonstrate the coal powder control measure can reduce the coal powder concentration into production well, and can extend the pump inspection cycle of CBM well.


Ju F.,China University of Mining and Technology | Zhang J.,China University of Mining and Technology | Zhang Q.,China University of Mining and Technology
International Journal of Mining Science and Technology | Year: 2012

For transportation of solid backfill material such as waste and fly ash from the surface to the bottom of the shaft in a fully mechanized backfilling coal backfilling coal mining technology, we developed a new vertical transportation system to transport this type of solid backfill material. Given the demands imposed on safely in feeding this material, we also investigated the structure and basic parameter of this system. For a mine in the Xingtai mining area the results show that: (1) a vertical transportation system should include three main parts, i.e., a feeding borehole, a maintenance chamber and a storage silo; (2) we determined that 486 mm is a suitable diameter for bore holes, the diameter of the storage silo is 6 m and its height 30 m in this vertical transportation system; (3) a conical buffer was developed to absorb the impact during the feeding process. To ensure normal implementation of fully mechanized backfillingcoal mining technology and the safety of underground personnel, we propose a series of security technologiesfor anti-blockage, storage silo cleaning, high pressure air release and aspiration. This vertical transportingsystem has been applied in one this particular mine, which has fed about 4 million tons solid material with a feeding depth of 350 m and safely exploited 3 million tons of coal. © 2012 Published by Elsevier B.V. on behalf of China University of Mining & Technology.


Liao Y.-F.,China University of Mining and Technology | Liu J.-T.,China University of Mining and Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2012

BP neural network model was used to predict the cleaned coal ash and combustible recovery in different operational conditions. Taking the circulation pressure, air flow, dosage of collector and frother as input set, the BP neural networkas prediction model was proposed to estimate the cleaned coal ash and combustible recovery as outputs. It is shown that BP neural network model can estimate the separation index quite satisfactorily in which the relative errors between the predicted values and experimental values are both less than 5% for the cleaned coal ash and combustible recovery.


Wang X.-Z.,China University of Mining and Technology | Xu J.-L.,China University of Mining and Technology | Zhu W.-B.,China University of Mining and Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2012

According to unusual development of water flowing fracture in some coal mines, further research on influence of primary key stratum stability to evolution of roof water flowing fracture and water level was carried out using methods of simulation experiment and engineering detection. The result indicates that water flowing fracture could reach the top of bedrock when the distance from primary key stratum to coal seam is less than 7~10 times of mining thickness, while the water flowing fracture above the primary key stratum, there appears two evolution types. When stable movement happens, in the process of stability from breakage, rotation to counter rotation of primary key stratum, the water flowing fracture experienced 'emergence-development-closure'. While sliding instability occurs, the water flowing fracture is hard to close with mining. The engineering detection results proved the law of primary key stratum structure stability on evolution of water flowing fracture. Therefore, measurement such as increasing support resistance can be used to avoid the sliding instability of main key stratum, which makes the water flowing fracture close progressively with mining and the water level gradually recovered to realize the aim of coal mining under water-containing.


Yao B.,China University of Mining and Technology | Bai H.,China University of Mining and Technology | Zhang B.,China University of Mining and Technology
International Journal of Mining Science and Technology | Year: 2012

Water-inrush in mine is one of the mine disasters caused by mining. In order to assess the risk of roof water-inrush in Wuyang Coal Mine based on the geological material of the coal mine, we built numerical models for the roof fracture and seepage development rule by using RFPA 2D and COMSOL respectively, to analyze the changes in fracture zone, stress, water pressure and seepage vector with the advancement of working face, and compared the results with the field investigated data. The numerical simulation results indicate that: (1) with the advancement of the working faces, the stress relief range and fracture zone in the overlying strata increased rapidly up to about 90 m, and then tended to remain constant, reaching a final height of about 95 m which agrees with the field investigation; (2) the seepage flow constantly increased with a larger flow volume both in the front and rear area, where the stress concentration are the most serious. © 2012 Published by Elsevier B.V. on behalf of China University of Mining & Technology.


SONG Z.,China University of Mining and Technology | LIN B.,China University of Mining and Technology
Mining Science and Technology | Year: 2010

Based on the assumption of a local non-equilibrium of heat transfer between a solid matrix and gas, a mathematic model of coal mine methane combustion in a porous medium was established, as well the solid-gas boundary conditions. We simulated numerically the flame propagation characteristics. The results show that the flame velocity in ceramic foam is higher than that of free laminar flows; the maximum flame velocity depends on the combined effects of a radiation extinction coefficient and convection heat transfer in ceramic foam and rises with an increase in the chemical equivalent ratio. The radiation extinction coefficient cannot be used alone to determine the heat regeneration effects in the design of ceramic foam burners. © 2010 China University of Mining and Technology.


Hong L.,China University of Mining and Technology
Advanced Materials Research | Year: 2014

In DSCM,mean of a seriously polluted target image's subdomain usually has a significant random fluctuation, this reduces the accuracy of subpixel registration. This paper proposed a algorithm to inhibit the fluctuation by replacing the mean of target subdomain with the mean of a superset domain. Experimental data shows that in some places this process can significantly improve the accuracy of correlation measure function's interpolation. © (2014) Trans Tech Publications, Switzerland.


Wang L.,China University of Mining and Technology | Cheng Y.-P.,China University of Mining and Technology
Resources Policy | Year: 2012

Coal mine methane (CMM) released during coal mining attributes to unsafe working conditions and environmental impact. China, the largest coal producer in the world, is facing problems associated with CMM such as fatal gas accidents and intense greenhouse gas emission along the path to deep mining. Complicated geological conditions featured with low permeability, high gas pressure and gas content of Chinese coal seams have been hindering the coal extraction. To solve these problems, a model of coal-methane co-exploitation is proposed. This model realizes the extraction of two resources with safety ensured and has been successfully applied in Huainan coalfield, China. The current situation of drainage and utilization of CMM in China are diagnosed. Connections between the coal production, methane emissions, drainage and utilization are analyzed. Estimations of future coal production, methane emissions, drainage and utilization are made in a co-exploitation based scenario. The emitted, drained and utilized CMM are projected to reach 26.6, 13.3 and 9.3 billion m 3, respectively by adapting the assumption of 3800 million metric tons of coal production by 2020. © 2012 Elsevier Ltd.


Wang W.W.,China University of Mining and Technology | Zhang M.,China University of Mining and Technology | Zhou M.,China University of Mining and Technology
Energy | Year: 2011

China has been the second CO2 emitter in the world, while the transportation sector accounts for a major share of CO2 emissions. Analysis of transportation sector CO2 emissions is help to decrease CO2 emissions. Thus the purpose of this paper is to investigate the potential factors influencing the change of transport sector CO2 emissions in China. First, the transport sector CO2 emissions over the period 1985-2009 is calculated based on the presented method. Then the presented LMDI (logarithmic mean Divisia index) method is used to find the nature of the factors those influence the changes in transport sector CO2 emissions. We find that: (1) Transport sector CO2 emissions has increased from 79.67 Mt in 1985 to 887.34 Mt in 2009, following an annual growth rate of 10.56%. Highways transport is the biggest CO2 emitter. (2) The per capita economic activity effect and transportation modal shifting effect are found to be primarily responsible for driving transport sector CO2 emissions growth over the study period. (3) The transportation intensity effect and transportation services share effect are found to be the main drivers of the reduction of CO2 emissions in China. However, the emission coefficient effect plays a very minor role over the study period. © 2011 Elsevier Ltd.


Chen L.,China University of Mining and Technology | Wu Z.,Shandong University
ESAIM - Control, Optimisation and Calculus of Variations | Year: 2012

In this paper, we study one kind of stochastic recursive optimal control problem for the systems described by stochastic differential equations with delay (SDDE). In our framework, not only the dynamics of the systems but also the recursive utility depend on the past path segment of the state process in a general form. We give the dynamic programming principle for this kind of optimal control problems and show that the value function is the viscosity solution of the corresponding infinite dimensional Hamilton-Jacobi-Bellman partial differential equation. © EDP Sciences, SMAI, 2012.


Cheng G.,China University of Mining and Technology | Shan X.,China University of Mining and Technology
Nonlinear Dynamics | Year: 2012

For a hip joint simulator with a 3SPS+1PS spatial parallel manipulator as the core module, a formulation based on the Kane equation was derived for the dynamic characteristics of the simulator from the kinematics analysis of the model. The relationships of the velocities and accelerations between the moving platform and active branched-chains were deduced. The velocity and angular velocity components of the moving platform were served as the generalized velocities. And the dynamic model was established by obtaining the generalized active forces and inertial forces. Then the driving forces and powers of the active branched-chains and the constraint reaction forces of the intermediate branched-chain were simulated in the numerical method. The results showed that the active driving forces of the branched-chains reached their respective maximum when the moving platform rotated into 0.13° around X-axis, 2° around Y-axis, and 18° around Z-axis. And the intermediate branched-chain needed to balance the driving and inertia forces, as well as support the moving platform and load the force of hydraulic cylinder. Therefore, the maximum constraint reaction force of the intermediate branched-chain is along the Zaxis. The research works provided a theoretical basis for the design of the active branched-chains driving system and the structural parameters of the intermediate branched-chain, as well as for the control system. © Springer Science+Business Media Dordrecht 2012.


Hongtao L.,China University of Mining and Technology | Shirong G.,China University of Mining and Technology | Shoufan C.,China University of Mining and Technology | Shibo W.,China University of Mining and Technology
Wear | Year: 2011

The artificial joint simulator is designed to simulate the complicated movement and environment of the artificial joint in vivo. Although the wear loss of materials evaluated on the artificial joint simulator under ISO standard is found to conform to that in vivo, there is a significant difference in the morphology of the wear debris obtained from the tester and human body. It is well known that the wear debris plays an important role in aseptic loosening of the artificial joint, and its morphology indicates the working conditions of the artificial joint. Therefore, it is necessary to distinguish the two kinds of wear debris. In this paper, the comparative study of ultra high molecular weight polyethylene (UHMWPE) wear debris from the implanted artificial joint and hip joint tester was performed on their size distribution, shape, 3-D feature, and thickness. Results show that the wear debris from joint simulator have different sizes and shapes such as strip, block, plate, and spherical etc., their average diameter is 7.54 μm, and its medium diameter is 6.89 μm. The most wear debris from artificial joint have the spherical or subsphaeroidal shapes, and a small amount of the debris have the unbroken plate structure, the average diameter is 1.33 μm, is about 18% of the wear debris' from joint simulator, and the medium diameter of 2.95 μm, is about 43% of the wear debris' from joint simulator. The results are expected to provide both experimental and theoretical foundation for improving the artificial joint simulator and optimizing the evaluation standards of the artificial joint materials. © 2011 Elsevier B.V.


Meng Q.-R.,China University of Mining and Technology
International Journal of Structural Integrity | Year: 2014

Purpose - The purpose of this paper is to reveal the temperature rise characteristics of the disc and pads under different load types. Design/methodology/approach - Evolutions of the disc and pads temperature under a stable, gradual changing and sine-wave contact pressures widely used at present are analyzed numerically by using ANSYS software. Findings - The results show that during the loading process, the temperature increases most rapidly under a stable contact pressure, most slowly under a gradual changing contact pressure; the disc temperature rise curves expose saw-shaped character, the closer it is to the friction surface, the more serious the fluctuations will be, the pads temperature rise curves are rather smooth; temperature gradient in the axial direction is higher than that in the other two directions under all of the three types of contact pressure and shows a sine-wave variation under a sine-wave contact pressure. Originality/value - It indicates that a gradual changing contact pressure should be adopted preferentially in practical application. The simulation results of this work provide theoretical basis for load simulation. Copyright © 2014 Emerald Group Publishing Limited. All rights reserved.


Ge S.,China University of Mining and Technology | Kang X.,China University of Mining and Technology | Zhao Y.,China University of Mining and Technology
Wear | Year: 2011

Ultra-high molecular weight polyethylene (UHMWPE) has been the most commonly used bearing materials in the total joint replacement. The biodegradation of implanted UHMWPE components has notable influence on wear and fatigue resistance. Although accelerated aging protocols in vitro have been developed to evaluate the oxidation behavior of the UHMWPE materials, the mechanism still remains not accurately understood. Thus, the biodegradation of UHMWPE in simulated body fluid (SBF) was performed for up to 12 months and the chemical structure (i.e. oxidation and crystallinity) and scratch resistance, punch shearing strength, friction and wear behavior of biodegraded UHMWPE samples were investigated in this work. The results provided strong evidence that oxidation degradation significantly reduced the crystallinity and in consequent decreased the wear and scratch resistance of UHMWPE. It was found that the oxygen content on UHMWPE surface increased by almost two times and the crystallinity degree decreased by 16%, resulting in the reduction of scratch coefficient and peak breaking load by 30% and 15%, respectively, after one-year biodegradation. Also, significant wear rate increase up to 6 times for the one-year degraded UHMWPE sample was noticed in this study, and an exponential decay relation for the wear rate of UHMWPE to the crystallinity was identified. A bi-linear behavior of the crystallinity and oxidation index on UHMWPE sample was discovered, which corresponded to the two-stage wearing volume growth of degraded UHMWPE. The preliminary study suggested the necessity of a full-scale biodegradation test for UHMWPE materials including oxidative, hydrolysis and biodeterioration and even dynamic rubbing process. Moreover, it was indicated scratch test as an effective method to evaluate the superficial properties of UHMWPE samples which may be used as an important tool on comparing friction and wear behavior of this material. © 2011 Elsevier B.V.


Xia W.,China University of Mining and Technology | Ni C.,China University of Mining and Technology | Xie G.,China University of Mining and Technology
Powder Technology | Year: 2016

The surface morphology plays a significant role in floatability, wettability and hydrophobicity of mineral particles. However, the existing investigations for revealing the relationship between surface roughness and wettability of mineral particles are not sufficient. Meanwhile, there are nearly no existing researches about relationships between surface roughness and coal particles due to the fact that coal is a mixture of organic and inorganic materials and hence the study is difficult to achieve. The aim of this paper was to investigate the influence of surface roughness on natural wettability of coal. Taixi ultra-low ash coal particles were used. In order to obtain coal particles having different surface roughness, coal particles were polished using sand papers with different meshes. The surface roughness of coal particles was characterized using scanning electron microscopy (SEM) and Mitutoyo SJ-210 surface roughness measurer, and the natural wettability of coal particles was characterized using contact angle measurement. Due to the measurements of SEM and surface roughness were conducted at the gold-coated coal surface, both the wettabilities of natural and gold-coated coal surface were obtained in this investigation. Throughout this paper, it was found that the surface roughness had a significant effect on the natural/gold-coated wettability of Taixi ultra-low ash coal. This paper indicates that the wettability of natural/gold-coated coal surface increases with the increase of surface roughness first, decreases second, and then has a little increase. © 2015 Elsevier B.V.


Rao Z.,China University of Mining and Technology | Zhao Y.,China University of Mining and Technology | Huang C.,China University of Mining and Technology | Duan C.,China University of Mining and Technology | He J.,China University of Mining and Technology
Progress in Energy and Combustion Science | Year: 2015

Globally, low rank coals are responsible for about half of the world's total coal deposits. However, these low rank coals present a high moisture content, which significantly impacts their utilization processes, including lower power plant efficiency, increased transportation costs, higher CO2 emission, and spontaneous combustion during storage. In order to decrease the energy consumption of low rank coal during the utilization processes, drying and dewatering technologies must be well designed. This review presents recent development in drying and dewatering technologies for low rank coals. Evaporative drying technologies, such as rotary-drying, fluidized-bed drying, hot oil immersion drying, hot oil-immersion drying, as well as non-evaporative drying technologies such as hydrothermal dewatering, mechanical/thermal dewatering, solvent extraction, are summarized in detail. Future research to upgrade low rank-coals, which are deposited in arid geological environments, is also suggested. © 2014 Elsevier Ltd. All rights reserved.


Sun Y.,China University of Mining and Technology
IET Signal Processing | Year: 2016

For the feature of zero delay in continuous relay transmission, wireless sensor networks (WSNs) supporting multiple communication interfaces is much suitable for data collection and transmission backbone network of coal mine safety monitor and control system which has high demand of reliability in real-time data transmission. Based on in-depth analysis of the existing distributed channel allocation algorithms, this study proposes an innovative fast distributed channel allocation scheme based on largest edges of network topology (CALENT) with the combination of wireless network architecture features. By comparing with existing distributed channel allocation dis-link algorithm, CALENT has better performance in co-channel interference index and convergence velocity. © The Institution of Engineering and Technology 2016.


Cai P.-J.,China University of Mining and Technology
Advanced Materials Research | Year: 2010

Nanocrystalline CuO with shuttle-morphology has been prepared conventionally by a microwave irradiation heating technique from an aqueous system in the presence of Cu(CH 3COO) 2·H 2O and NaOH at room temperature. The X-ray powder diffraction pattern indicates that the product is indicated that the product was pure monoclinic phase of CuO. Further characterized by transmission electron microscopy, selected area electron diffraction, X-ray photoelectron spectroscopy and Raman spectra, the component of the products were confirmed. © (2010) Trans Tech Publications.


Xiao H.,Hefei University of Technology | Sun J.,Hefei University of Technology | Chen P.,China University of Mining and Technology
Journal of Hazardous Materials | Year: 2014

An experimental and numerical study of dynamics of premixed hydrogen/air flame in a closed explosion vessel is described. High-speed shlieren cinematography and pressure recording are used to elucidate the dynamics of the combustion process in the experiment. A dynamically thickened flame model associated with a detailed reaction mechanism is employed in the numerical simulation to examine the flame-flow interaction and effect of wall friction on the flame dynamics. The shlieren photographs show that the flame develops into a distorted tulip shape after a well-pronounced classical tulip front has been formed. The experimental results reveal that the distorted tulip flame disappears with the primary tulip cusp and the distortions merging into each other, and then a classical tulip is repeated. The combustion dynamics is reasonably reproduced in the numerical simulations, including the variations in flame shape and position, pressure build-up and periodically oscillating behavior. It is found that both the tulip and distorted tulip flames can be created in the simulation with free-slip boundary condition at the walls of the vessel and behave in a manner quite close to that in the experiments. This means that the wall friction could be unimportant for the tulip and distorted tulip formation although the boundary layer formed along the sidewalls has an influence to a certain extent on the flame behavior near the sidewalls. The distorted tulip flame is also observed to be produced in the absence of vortex flow in the numerical simulations. The TF model with a detailed chemical scheme is reliable for investigating the dynamics of distorted tulip flame propagation and its underlying mechanism. © 2014 Elsevier B.V.


Tang W.,China University of Mining and Technology | Wang Y.,China University of Mining and Technology
Applied Surface Science | Year: 2012

The fracture surfaces have self-similar properties and are mostly expressed in the form of two-dimensional digital image. In this paper, a pixel-covering method is applied and an improvement is made to research the fractal characterization of the steel impact fracture surface. The results show that taking boundary to the feature parts of the gray image can increase the accuracy of the fractal dimension. The linearity of the fractal dimension curves of impact fractures is obvious, indicating the impact fractures have fractal properties and the pixel-covering method can describe it. Fractal dimension can be a parameter reflecting the roughness of the impact fracture surface. Rougher the surface is, the higher is the fractal dimension. There is a positive correlation between the fractal dimension of the impact fracture and the toughness of the material. It would be possible to establish a quantitative correlation between fractal dimension, surface roughness, impact toughness, and fracture mechanism, which presents a good potential to material and failure analysis of material. © 2011 Elsevier B.V. All rights reserved.


Li Y.,China University of Mining and Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2011

This paper analysed the overburden movement in cemented backfill mining by using computer simulated model, observed the overburden movement in different mining advances distance, compared to traditional longwall mining and fonnd the characteristic of overburden movement in backfill mining. The overburden movement in solid waste rock cemented backfill mining was different from what it was in traditional longwall mining. The studies show that the range of periodic weighting is relatively wide in back fill mining, and the weighting strength is also low; the key rock strata will be bending subsidence without failure situation. The displacement of overburden movement can be dramatically decreased. As a result, ground surface deformation can be well controlled.


Liu J.-C.,China University of Mining and Technology | Wang J.-G.,Northwestern Polytechnical University
CMES - Computer Modeling in Engineering and Sciences | Year: 2014

We consider the determination of heat flux within a body from the Cauchy data. The aim of this paper is to seek an approach to solve the onedimensional heat equation in a bounded domain without initial value. This problem is severely ill-posed and there are few theoretic results. A quasi-reversibility regularization method is used to obtain a regularized solution and convergence estimates are given. For numerical implementation, we apply a method of lines to solve the regularized problem. From numerical results, we can see that the proposed method is reasonable and feasible. Copyright © 2014 Tech Science Press.


Ma Q.,China University of Mining and Technology | Harpalani S.,Southern Illinois University Carbondale | Liu S.,Southern Illinois University Carbondale
International Journal of Coal Geology | Year: 2011

Significant changes occur in the absolute permeability of coalbed methane (CBM) reservoirs during primary depletion or enhanced recovery/CO2 sequestration operations. In order to project gas production, several analytical models have been developed to predict changes in coal permeability as a function of stress/porosity and sorption. Although these models are more transparent and less complicated than the coupled numerical models, there are differences between the various analytical models and there are several uncertainties. These are discussed briefly in this paper. A new model is then proposed, which is based on the volumetric balance between the bulk coal, and solid grains and pores, using the constant volume theory. It incorporates primarily the changes in grain and cleat volumes and is, therefore, different from the other models that lay heavy emphasis on the pore volume/cleat compressibility values. Finally, in order to demonstrate the simplicity of the proposed model, a history matching exercise is carried out using field data in order to compare the different models. The modeling results suggest that the agreement between the predicted permeability using the existing models and the one proposed here is very good. The merit of the proposed model is its simplicity, and the fact that all input parameters are easily measurable for any coal type with no uncertainties. © 2010 Elsevier B.V.


Sun J.,China University of Mining and Technology | Wang L.,China University of Mining and Technology
Mining Science and Technology | Year: 2011

Grooving method can restrain the deformation and destruction of surrounding rock by transferring the maximum stress to deep rock, bringing about the effective control for floor heave in soft rock roadway. Based on this important effect, and to discuss the relationship between cutting parameters and pressure-relief effect, this paper carried out a numerical simulation of grooving along bottom slab and two sides of gateway with finite difference software FLAC2D. The results show that the control effect on floor heave in soft rock tunnel can be improved by selecting appropriate cutting parameters. Appropriately increasing the crevice depth in the middle of the floor can improve the stress state of bottom slab by stress transfer. So the floor heave can be more effectively controlled. To lengthen the crevice in the corners of roadway can simultaneously transfer the maximum stresses of bottom slab and two sides to deep rock, and promote the pressure-relief effect. Extending the crevice length and crevice width on both sides within a certain range can decrease the stress concentration in the corners of roadway, and reduce the deformation of two sides. The cutting position beneficial to restrain the floor heave is close to the bottom slab. © 2011, China University of Mining & Technology. All rights reserved.


Liu J.,China University of Mining and Technology | Zhang H.,University of Chinese Academy of Sciences | Zhang Y.,China University of Mining and Technology | Chai T.,University of Chinese Academy of Sciences
Plant Physiology and Biochemistry | Year: 2013

Solanum nigrum L. is considered to be a potential plant for restoring Cd-contaminated soils. Si could enhance plants tolerance to heavy metal; however, the mechanism of Si-mediated alleviation of Cd toxicity in S.nigrum was not clear. Three-week-old S.nigrum seedlings were grown in Hoagland solution containing 0 or 100μM Cd with or without 1mM Si for 4 days. The results showed that the Cd concentration both in roots and shoots of Si-supplied plant was significantly reduced, especially in expanding and old leaves. The relative proportion of ethanol-extractable Cd, water-extractable Cd and NaCl-extractable Cd in roots was increased by adding Si, while the root-to-shoot Cd translocation was not decreased. Furthermore, in comparison with single Cd treatment, supplying Si could reduce H2O2 accumulation and cell death in roots, and the electrolyte leakage and H2O2 concentration in functional leaves. Moreover, the activity of superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), peroxidase (POD, EC 1.11.1.7) and ascorbate peroxidase (APX, EC 1.11.1.11) in functional leaves was markedly increased by Cd exposure, while the antioxidative enzyme activities in Cd plus Si treatment seedlings were significantly lower than that in Cd treatment alone, this decrease might be attributed to the reduction of Cd concentration and Cd-induced oxidative damages. These results demonstrate that Si-enhanced Cd tolerance in S.nigrum is mainly due to the decrease of Cd uptake in roots and Cd distribution in expanding and old leaves, as well as lowering oxidative stress induced by Cd in plants. © 2013 Elsevier Masson SAS.


Wu D.,China University of Mining and Technology
Ionics | Year: 2012

Li 4Ti 5O 12 anode was successfully synthesized by solid-state method. X-ray diffraction and scanning electron micrographs show that Li 4Ti 5O 12 prepared by solid-state method has a purity phase with a uniform particle size in the range of 0.5-1 μm. Cyclic voltammogram reveals that there is a big irreversible capacity for the first cycle. Li 4Ti 5O 12 shows a stable cycling stability at 1 C rate. After 152 cycles, the discharge capacity is 213 mAh g -1, which keeps 93% of it at the second cycle. Electrochemical impedance spectroscopy shows that the resistance of charge-transfer of Li 4Ti 5O 12 electrode decreased with increasing the storage temperatures, and the lithium diffusion coefficient is increased with increasing the storage temperatures, revealing that the kinetics of Li + and electron transfer into the electrodes were much faster at high temperature than that at low temperature. The apparent activation energy of the charge transfer and lithium diffusion can be calculated to be 33.1 and 27.3 kJ mol -1, respectively. © 2011 Springer-Verlag.


Wei F.,China University of Mining and Technology | Fang L.,China University of Mining and Technology | Huang Y.,China University of Mining and Technology
Inorganica Chimica Acta | Year: 2010

In this paper, we report four phosphorescent Cu(I) complexes of [Cu(OP)(PPh3J2]BF4, [Cu(MeOP)(PPh 3)2]BF4, [Cu(OP)(POP)]BF4, and [Cu(Me-OP)(POP)]BF4 with oxadiazole-derived diimine ligands, where OP-2-(5-phenyl-[l,3,4]oxadiazol-2-yl)-pyridine, Me-OP-2-(5-p-tolyl-[1,3,4] oxadiazol-2-yl)pyridine, POP-bis(2-(diphenyIphosphanyl)phenyl) ether, and PPh3 - triphenylphosphane, including their synthesis, crystal structures, photophysical properties, and electronic nature. The Cu(I) center has a distorted tetrahedral geometry within the Cu(I) complexes. Theoretical calculation reveals that all emissions originate from triplet metal-to-ligand-charge-transfer excited state. It is found that the inter-molecular sandwich structure triggered by inter- and intra-molecular pi-stacking within solid state Cu(I) complexes is highly effective on restricting the geometric relaxation that occurs in excited states, and thus greatly enhances the photoluminescence (PL) performances, including PL quantum yield improvement, PL decay lifetime increase, and emission blue shift. © 2010 Elsevier B.V. All rights reserved.


Wang Q.,China University of Mining and Technology | Zhang L.,China University of Mining and Technology | Shen H.,China University of Mining and Technology
Surface and Coatings Technology | Year: 2010

Medical cast and forged CoCrMo alloys were coated by the plasma nitrided process to enhance the wear resistance. The microstructures, phases and microhardness of nitrided layers were studied by AFM, SEM, XRD and a micro-hardness meter. The experimental results showed that the plasma nitrided process has shown promise in producing thicker, harder, and more wear resistant layers than the conventional CoCrMo alloys. At low nitriding temperatures, the structures appeared to be consistent with the formation of S-phase, CrN phases in a parent structure of α-(CoCr) for the cast and forged alloy. At high nitriding temperatures, both cast and forged samples appeared to form CrN and Cr2N as well as α-(CoCr) phases. Whether cast or forged CoCrMo alloy, the thickness of the nitrided layer increased with the nitriding temperatures. Moreover, the thickness of nitrided layers for forged alloys was higher than cast alloys under the same nitriding conditions. In the case of the cast and forged CoCrMo alloys, all plasma nitrided samples showed much higher hardness than the untreated samples. © 2010 Elsevier B.V.


Wu X.,China University of Mining and Technology
International Journal of Advancements in Computing Technology | Year: 2012

Extreme learning machine (ELM) is an efficient algorithm for single-hidden layer feedforward neural networks (SLFNs), which can produce good generalization performance in most cases and learn thousands of times faster than conventional popular algorithms. However, the performance of ELM is sensitive to the initialized number of hidden neurons. In some traditional methods, the number of hidden nodes is gradually increased by a fixed interval to select the nearly optimal number of nodes for ELM, whereas these methods are of a little bit of complexity and quite time-consuming. This paper proposes an improved ELM based on the affinity propagation clustering, which does not need to define the number of hidden nodes in advance manually and randomly. The proposed algorithm automatically determines the number of hidden nodes for different data sets. Empirical study of AP-based ELM on several commonly used classification benchmark problems shows that it achieves better performance compared with the standard ELM.


Wang D.M.,China University of Mining and Technology | Hou Y.F.,China University of Mining and Technology | Hou Y.F.,Xuzhou Wuyang Technology Co. | Tian Z.Z.,China University of Mining and Technology
Smart Materials and Structures | Year: 2013

The extremely severe heating of magnetorheological (MR) brakes restricts their application in high-power situations. This study aims to develop a novel MR brake with a high-torque capacity. To achieve this goal, a water cooling method is adopted to assist in heat dissipation. In the study, a structural model design of the high-torque MR brake is first developed according to the transmission properties of the MR fluid between the rotating plates. Then, the operating principle of the MR brake is illustrated, which is followed by a detailed design of the water channel. Moreover, theoretical analysis, including the transmitted torque, magnetic field and thermal analysis, is performed as well. After this, an experimental prototype of the proposed MR brake is fabricated and assembled. Then the torque transmission and heat dissipation of the prototype are experimentally investigated to evaluate the torque transmission properties and water cooling efficiency. Results indicate that the proposed MR brake is capable of producing a highly controllable brake torque, and the water cooling method can effectively assist in heat dissipation from the MR brake. © 2013 IOP Publishing Ltd.


Wang Y.,China University of Mining and Technology
Advanced Materials Research | Year: 2010

Since the early 1980s, great progress has been made in microbubble column flotation technology. As one of the important mineral processing methods, the application and development of this technology in China are summarized in this paper from four respects. Firstly, a patented cyclonestatic microbubble separation method was proposed to overcome the notable problems mentioned in the previous flotation columns. Secondly, microbuble column flotation was introduced to separate the high ash as well hard-to-separate coal slime generated from dense medium processes. The characteristics of the microbubble column, and the flotation process for fine coal and the high ash coal separation was analyzed. Thirdly, the application of microbubble column flotation in China was detailed introduced, especially the characteristics of series microbubble column flotation equipment, and efficient column type coal slime separation crafts were discussed. The application of microbubble column flotation particularly in low ash content coal preparation, and discarded coal slime processing technology were presented. Finally, microbubble column flotation has been extended to non-coal mineral processing, such as magnetite concentrate upgrading (concentration iron and removing silicon), sulfide copper mine separation, white tungsten flotation, etc., the related research was briefly introduced in this paper as well. © (2010) Trans Tech Publications.


Tang J.,China University of Mining and Technology | Luo J.-M.,China University of Mining and Technology | Ma J.,Lanzhou University of Technology
PLoS ONE | Year: 2013

A coupled model containing two neurons and one astrocyte is constructed by integrating Hodgkin-Huxley neuronal model and Li-Rinzel calcium model. Based on this hybrid model, information transmission between neurons is studied numerically. Our results show that when the successive spikes are produced in neuron 1 (N1), the bursting-like spikes (BLSs) occur in two neurons simultaneously during the spikes being transferred to neuron 2 (N2). The existence of the astrocyte and a higher expression level of mGluRs facilitate the occurrence of BLSs, but the rate of occurrence is not sensitive to the parameters. Furthermore, time delay τ occurs during the information transmission, and τ is almost independent of the effect of the astrocyte. Additionally, we found that low coupling strength may result in the distortion of the information, and this distortion is also proven to be almost independent of the astrocyte. © 2013 Tang et al.


Jiang H.,China University of Mining and Technology | Sun R.,China University of Mining and Technology
Applied Mathematics and Information Sciences | Year: 2014

Learning from the concept of potential field in physics, the hybrid virtual potential field of the wireless sensor network was constructed based on the hop and the residual energy of nodes. Aimed at maximizing the network lifetime, we proposed an energy optimized routing algorithm for multi-sink wireless sensor networks, using virtual force of the virtual potential field as the routing decision criteria. Avoid strategy for low-energy nodes and load balancing strategy for multiple sinks were applied to dynamically adjust the potential value and achieve balanced energy consumption of nodes. Simulation results show that the routing algorithm balances the energy consumption of nodes effectively and extends the network lifetime, compared with similar algorithms. © 2014 NSP Natural Sciences Publishing Cor.


Chen B.,Northwest University, China | Diao Z.-J.,China University of Mining and Technology | Lu H.-Y.,China National Institute of Clean and Low Carbon Energy
Fuel | Year: 2014

The aim of this work is the investigation of the detailed mechanisms for the initiation reaction leading to the spontaneous combustion of lignite. To carry this out we have used the ReaxFF reactive force field to perform a series of molecular dynamics (MD) simulations on a unimolecular model compound. The initiation reaction observed in the ReaxFF MD simulations involves hydrogen abstraction from phenolic hydroxyl groups by O2 followed by the formation of HO2. The main products observed in our simulations include H2O2, H2O, CH2O, and CO 2. In addition, hydrogen abstraction reactions are responsible for the formation of H2O2 and H2O. The reaction products and the mechanisms involved in the initial stage of spontaneous combustion are consistent with previous results. The agreement of these results with available experimental observations demonstrates that ReaxFF MD simulations can provide an atomistic description of the initiation mechanism for spontaneous combustion and provide useful insights into the complicated reaction processes involved. © 2013 Elsevier Ltd. All rights reserved.


Xu S.,China University of Mining and Technology | Li W.,China University of Mining and Technology | Xing F.,China University of Mining and Technology | Wang Y.,China University of Mining and Technology
Optics Express | Year: 2014

A polarimetric current sensor based on polarization division multiplexing (PDM) detection is proposed. The novel sensor head with a heat insulation cavity only induces a small level of birefringence. Comparing with polarization diversity (PD) detection, the sensitivity of PDM detection is the double of PD detection. Moreover, PDM detection is more suitable in the presence of the phase modulation error. In addition, the noise and the shifting of the Verdet constant are proved to be the main influence factors of the sensor performance as the source power decline. © 2014 Optical Society of America.


Yang H.,China University of Mining and Technology | Qin Y.,China University of Mining and Technology | Feng G.,Jiangsu University | Ci H.,China University of Mining and Technology
IEEE Sensors Journal | Year: 2013

A remote online carbon dioxide (CO2) concentration monitoring system is developed, based on the technologies of wireless sensor networks, in allusion to the gas leakage monitoring requirement for CO2 capture and storage. The remote online CO2 monitoring system consists of monitoring equipment, a data center server, and the clients. The monitoring equipment is composed of a central processing unit (CPU), air environment sensors array, global positioning system (GPS) receiver module, secure digital memory card (SD) storage module, liquid crystal display (LCD) module, and general packet radio service (GPRS) wireless transmission module. The sensors array of CO2, temperature, humidity, and light intensity are used to collect data and the GPS receiver module is adopted to collect location and time information. The CPU automatically stores the collected data in the SD card data storage module and displays them on the LCD display module in real-time. Afterwards, the GPRS module continuously wirelessly transmits the collected information to the data center server. The online monitoring WebGIS clients are developed using a PHP programming language, which runs on the Apache web server. MySQL is utilized as the database because of its speed and reliability, and the stunning cross-browser web maps are created, optimized, and deployed with the OpenLayers JavaScript web-mapping library. Finally, an experiment executed in Xuzhou city, Jiangsu province, China is introduced to demonstrate the implementation and application. © 2001-2012 IEEE.


Chen H.,China University of Mining and Technology | Feng Q.,China University of Mining and Technology | Long R.,China University of Mining and Technology | Qi H.,China University of Mining and Technology
Safety Science | Year: 2013

The trend in Chinese coal miners' occupational diseases in the last ten years was studied by comparison with US reference data. It showed that the legally recorded occupational diseases of American coal miners had a wider range than that of China. Even so, the total number of occupational diseases and the number of occupational diseases per million tons of coal produced in Chinese coal mines were 32.9, 18.3 times higher than those in the US. In addition, the number of cases of coal miners' occupational disease was, on average, 54.08% of the total number of cases in industry as a whole, which was 12.6 times more than that in the US. The occupational disease rate per thousand coal miners in China recently increased, and reached a new peak in 2010, while showing a downward trend in the US. Pneumoconiosis was the main occupational disease of Chinese coal miners with over 75%. In 2008, 2009, and 2010, the number of coal miners suffering from pneumoconiosis reached 4311, 5997 and 12,208, respectively, and accounted for 78.79%, 79.95% and 87.41% of the total occupational diseases, respectively. Compared to the US, Chinese coal miners were in a much worse occupational disease status. Based on US experience, some improvement strategies were proposed. © 2012 Elsevier Ltd.


Feng Q.,China University of Mining and Technology | Chen H.,China University of Mining and Technology
Safety Science | Year: 2013

Coal production is an activity with marketable output and safety output, and the interaction between coal production and safety inputs reflects the relationship between economic development and occupational safety. Through analysis of the long-term interaction between coal production and safety inputs, this paper divides a country's stages of safety level into developing stage, stable stage and transcending stage. According to the basic principle of the Cobb-Douglas production function, a coal production model is set up, and regression analysis is conducted using EViews software. The results indicate that China has not yet achieved the best balanced status but has remained in the developing stage; while the US has been in the stable stage. The impulse response curves indicate that the rate of technological progress had the most obvious response and that technological progress was an important support of economic output. For China, the safety input showed a secondary effect and was also an effective method for improving economic output. However, the labor growth rate had little influence on coal production and no direct impact on economic output at this stage. If the difference in development stages is measured only by labor productivity, then China needs at least 30. years to reach the safety production level of the US. Some suggestions to enhance Chinese coal-mine safety are proposed through learning from the US and Australian experience. © 2012 Elsevier Ltd.


Guo S.-D.,China University of Mining and Technology
Journal of Magnetism and Magnetic Materials | Year: 2016

Binary transition-metal pnictides and chalcogenides half-metallic ferromagnetic materials with zincblende structure, being compatible with current semiconductor technology, can be used to make high-performance spintronic devices. Here, we investigate electronic structures and magnetic properties of composite structure ((CrX)2/(YX)2 (X=As, Sb; Se, Te and Y=Ga; Zn) superlattices) of zincblende half-metallic ferromagnetism and semiconductor by using Tran and Blaha's modified Becke and Johnson (mBJ) exchange potential. Calculated results show that they all are half-metallic ferromagnets with both generalized gradient approximation (GGA) and mBJ, and the total magnetic moment per formula unit follows a Slater-Pauling-like "rule of 8". The key half-metallic gaps by using mBJ are enhanced with respect to GGA results, which is because mBJ makes the occupied minority-spin p-bands move toward lower energy, but toward higher energy for empty minority-spin Cr-d bands. When the spin-orbit coupling (SOC) is included, the spin polarization deviates from 100%, and a most reduced polarization of 98.3% for (CrSb)2/(GaSb)2, which indicates that SOC has small effects, of the order of 1%, in the considered four kinds of superlattice. © 2016 Elsevier B.V. All rights reserved.


Gong D.-W.,China University of Mining and Technology | Qin N.-N.,China University of Mining and Technology | Sun X.-Y.,China University of Mining and Technology
Information Sciences | Year: 2011

Many optimization problems in real-world applications contain both explicit (quantitative) and implicit (qualitative) indices that usually contain uncertain information. How to effectively incorporate uncertain information in evolutionary algorithms is one of the most important topics in information science. In this paper, we study optimization problems with both interval parameters in explicit indices and interval uncertainties in implicit indices. To incorporate uncertainty in evolutionary algorithms, we construct a mathematical uncertain model of the optimization problem considering the uncertainties of interval objectives; and then we transform the model into a precise one by employing the method of interval analysis; finally, we develop an effective and novel evolutionary optimization algorithm to solve the converted problem by combining traditional genetic algorithms and interactive genetic algorithms. The proposed algorithm consists of clustering of a large population according to the distribution of the individuals and estimation of the implicit indices of an individual based on the similarity among individuals. In our experiments, we apply the proposed algorithm to an interior layout problem, a typical optimization problem with both interval parameters in the explicit index and interval uncertainty in the implicit index. Our experimental results confirm the feasibility and efficiency of the proposed algorithm. © 2011 Elsevier Inc. All rights reserved.


Yang S.-Q.,China University of Mining and Technology | Jing H.-W.,China University of Mining and Technology
Engineering Geology | Year: 2013

Triaxial compression experiments were carried out for red sandstone to investigate its strength and deformation failure behavior under simple and complex loading paths. In this research, tested confining pressure is in the range from 5 to 35. MPa. Under simple loading path, the peak strength, residual strength and critical damage threshold of red sandstone all increase with the confining pressure, which are in good agreement with the linear Mohr-Coulomb criterion. To investigate the re-fractured mechanical behavior of pre-cracked red sandstone with different post-peak stress drops, two complex loading paths with only one specimen are put forward to obtain the strength and deformation parameters of red sandstone. The differences of strength and deformation parameters of red sandstone between simple and complex loading paths are evaluated detailed. The elastic moduli of red sandstone under simple and complex loading paths all increase nonlinearly with the confining pressure. It is suggested and recommended to predict the peak strength of rock under simple loading path by adopting complex loading path A (increasing gradually the confining pressure) not complex loading path B (reducing gradually the confining pressure). On the basis of the linear Mohr-Coulomb criterion, a kind of new method is put forward to revise the peak strength of red sandstone under complex loading path A, which is testified to be right and reasonable. The investigated conclusions are very significant for ensuring the stability and safety of deep underground rock engineering. © 2013.


Yu J.,China University of Mining and Technology | Wu L.,China University of Mining and Technology
Wuhan Daxue Xuebao (Xinxi Kexue Ban)/Geomatics and Information Science of Wuhan University | Year: 2015

The SDOG-based Earth System Spatial Grid (SDOG-ESSG) is an important tool and method in the Earth System Science and spatial information domains. This paper focuses on the key problem of transformation between the grid code of SDOG-ESSG and the existing spatial reference, the transformation between Spheroid Coordinates System (SCS) and the grid code of SDOG-ESSG. Six column-row-layer number systems were brought in and related formulas were derived. Based on this and the bit-interleaving method of Morton code, forward and backward transformation algorithms were developed. The time efficiency of both algorithms was analyzed theoretically and experimentally. The results show that: a) both algorithms are very high efficient, and the time consumption is linear to the principle subdivision level and the further subdivision level of SDOG-ESSG, where the time complexity is O(n); and (b) approximately 106~107 times of transformation operations can be done in one second under current personal computer. Each transformation operation is identical to 101~102 division operation in time.


Denggao H.,China University of Mining and Technology | Xun F.,China University of Mining and Technology
Advanced Materials Research | Year: 2013

Hydraulic support is one of the most important equipments of coal mine exploration, this thesis is to analyse hydraulic support strength and reliability with finite element method. With the example of ZF8000/22/35 hydraulic support, this paper uses the Hyper Works finite element software to analyse the strength of the hydraulic support, and then, with the ANSYS, this paper calculates the reliability of the hydraulic support and figures out the sensitivity of the hydraulic support. Finally, some methods of reliability analysis with finite element method are summarized,these methods can give reference to the design of hydraulic support. © (2013) Trans Tech Publications, Switzerland.


Yin S.,China University of Mining and Technology | Xu S.,Zhejiang University
Advanced Materials Research | Year: 2011

The influences of the mesh sizes, the surface treatment and cover thickness of the textile on anti-crack and bearing capacity of the competent were investigated. Additionally, to prevent the splitting of the concrete, hanging U-shaped hook upon textiles was also experimentally studied. The experiment results indicate that sticking sand on epoxy resin-impregnated textile and reduced cover thickness are helpful to improve the mechanical performance of the component; the textile with 10mm×10mm mesh size is superior than that with 20mm×20mm mesh size regardless of in the respect of enhancing the bearing capacity of the TRC or in the respect of controlling matrix cracking; the novel method of adding U-shape iron hook not only can improve the bonding performance between the textile and the concrete, but also can enhance the shearing capacity of the concrete.


Chen H.,China University of Mining and Technology | Gu J.J.,Dalhousie University
IEEE/ASME Transactions on Mechatronics | Year: 2010

This paper presents two three-phase switched reluctance machine systems. One is the dual motors drive for the electric locomotive traction; the other is the variable-speed generator system for wind power applications. The principles of the switched reluctance machine system operated at four quadrants, the scheme of the symmetrical traction at quadrant I and quadrant III, and the scheme of the symmetrical regenerative braking control at quadrant II and quadrant IV, are given. The transient phase current analysis and the energy analysis of the switched reluctance machine system at the operational state of braking or generating are evaluated, and the rotor position and the peak value of the phase current at three different conditions are given. The closed-loop rotor speed control of the main motor, synchronization of the rotor speed, and balance distribution of loads between the main motor and the subordinate motor have been implemented by the fuzzy logic algorithm. The closed-loop output power control of the switched reluctance wind power generator system implemented by regulating the turn-on angle of the main switches with fuzzy logic algorithm and fixed turn-off angle of the main switches is also presented. The major components of the two prototypes are explained in detail. The experimental results of the dual 7.5-kW three-phase 6/4 structure switched reluctance motors (SRMs) parallel drive system prototype are included. It is shown that the maximum difference in the output torque of the two motors at the same given rotor speeds is within 10.00 and the maximum difference in the practical rotor speed of the two motors is within 5.00. The tested results of three-phase 12/8 structure switched reluctance variable-speed wind power generator system show that the error of the closed-loop output power control is within 2.2, while the rotor speed range is close to the ratio of 1:3 with the low rotor speed 405 r/min. The average dc line current of the power converter can be utilized as a feedback signal for the actual output torque of SRM drive or a feedback signal for the actual output power of switched reluctance generator system. © 2006 IEEE.


Song Y.,North China University of Technology | Yang X.,China University of Mining and Technology
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2013

The evolution characteristics of deformation fields and temperature fields are inspected and analyzed by using the digital speckle correlation method and infrared thermal imager. The test material is a kind of coal and the specimens are loaded by uniaxial test machine. The analytical results show that: (1) The deformation field evolution of coal specimen is divided into two phases: initial uniform deformation evolution to deformation localization at pre-peak loading stage, and deformation concentration in the localization band at post-peak loading stage. (2) The temperature evolution of coal specimen is divided into two phases: temperature rises due to internal particle spacing change caused by thermo-mechanical coupling effect at pre-peak loading stage; temperature decreases due to the tensile-shear effect and the sliding effect of deformation localization band at post-peak loading stage. (3) The temperature change is obvious in the deformation and destruction process of coal specimens; and the temperature evolution characteristics are similar inside and outside the deformation concentration band. The temperature increases at pre-peak loading stage and decreases at post-peak loading stage. The temperature inside the deformation localization band is higher than that outside the deformation localization band.


Xia Q.,China University of Mining and Technology
Zhongguo Kuangye Daxue Xuebao/Journal of China University of Mining and Technology | Year: 2013

The paper used Haken model of Synergetics in self-organization theory to study the evolution of modern service industry, based on the investigation of the self-organizing feature of the modern service industry system. At first, the paper analyzed the order parameter and control variables for modern service industry's evolution by adiabatic elimination method and built the evolution model of modern service industry. Secondly, after the model solving through panel data analysis methods, trend function of the evolution was constructed, and the process and discipline of modern service industry's evolution was simulated. From the analysis of control variables in the model, it is easy to conclude that the labor productivity in the chosen variables represents the technology progress and innovation, and is the conducted order parameter in the evolution of modern service industry. And at the same time, labor productivity and investment rate could interact with each other. So they are both the main influencing factors of the evolution, which exist the feedback mechanism of system evolution.


Gu M.,Nanjing University | Wang J.,China University of Mining and Technology | Wu X.S.,Nanjing University | Zhang G.P.,Indiana State University
Journal of Physical Chemistry C | Year: 2012

Intrinsic defects are crucial to the electronic and magnetic properties in the SrTiO3/LaAlO3 (STO/LAO) system. With the first-principles simulation, we construct a formation energy phase diagram of different intrinsic defects on STO surfaces. The three most stable surface defects are Al-substitution of Ti, La-substitution of Sr, and the oxygen vacancy at TiO2 surface. On STO, multiple defects are possible. When these defective surfaces form interfaces with LAO, the Al substitution of Ti atom is highly favored energetically. Defects of this type can change the n-type interface into p-type. The polar STO/LAO interface is found to effectively compensate the internal electric field, leading to a wider band gap in the system with both n- and p-type interfaces. © 2012 American Chemical Society.


Sun J.-P.,China University of Mining and Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2010

Introduced the condition of safety monitoring and communication technologies at the coal mine from safety monitoring and control system, underground personnel locating system, coal output remote monitoring system, whole mine mobile communication system and unattended remote monitoring and control system. On this basis looked into the prospect of technologies development of safety monitoring and communication in the coal mine, such as: technology of mining internet of things, integration communications technology and system of coal mine, remote control technology of manless working face and coal-rock interface recognition technology, accurate personnel positioning technology and system at the underground coal mine, severe disaster early-warning technologies for gas, fire and rock burst based on safety monitoring and control system, coal mine safety production management information system based on 3D GIS, technology and equipment of life-detecting in the underground coal mine, intrinsic safety communication technologies of wireless communication and optical fiber, sensor arrangement method of no-blind area, rescue robot in the underground coal mine, etc.


Gang L.,China University of Mining and Technology
2011 2nd International Conference on Artificial Intelligence, Management Science and Electronic Commerce, AIMSEC 2011 - Proceedings | Year: 2011

Notice of Retraction After careful and considered review of the content of this paper by a duly constituted expert committee, this paper has been found to be in violation of IEEE's Publication Principles We hereby retract the content of this paper. Reasonable effort should be made to remove all past references to this paper. The presenting author of this paper has the option to appeal this decision by contacting TPII@ieee.org.


Chen L.,China University of Mining and Technology | Yu Z.,Shandong University
IEEE Transactions on Automatic Control | Year: 2015

In this technical note, we discuss a nonzero-sum stochastic differential game with delays. Not only the state variable, but also control variables of players involve delays. This kind of games are motivated by some interesting problems arising from economics and finance. Using anticipated backward stochastic differential equations, we establish a necessary condition and a sufficient condition of maximum principle for the delayed game problem. To explain theoretical results, we apply them to an economic problem. © 1963-2012 IEEE.


Cheng J.,China University of Mining and Technology | Zhou F.,China University of Mining and Technology
Fire Technology | Year: 2015

Gas explosions or mine fires present the safety threats for coal miners or mine rescues members. For an explosive atmosphere in the underground mine, careful determination of its explosibility status and applying some mitigations to switch an explosive atmosphere into a non-explosive one are very important for any underground rescues or a mine fire extinguishment. However, due to the complicated compositions in an underground sealed atmosphere, accurate determination of the explosibility of such atmosphere status is always a knotty problem for mining engineers. Beside of that, a proper estimation method for the needed time span when an explosive atmosphere is artificially or naturally changed into a non-explosive is also urgently desired. In order to improve the mine safety, this paper is going to address such mentioned problems. The original Coward explosibility diagram is modified with handling the combination effects of different inert gases for more accurate determining the explosibility of an underground sealed atmosphere which consists of complex gas compositions. Then, based on the revised explosibility diagram, a set of mathematical equations are theoretically derived to estimate the inertisation time of a sealed mine atmosphere by using different inerting approaches. Such research efforts can help mine operators understand the risk and provide a tool to control such atmosphere away from dangerous conditions. In order to demonstrate the research findings, at the end of the paper, the explosibility of gas sample taken from a real mine has been analyzed by using the revised Coward diagram. Also, the different inertisation time durations of various mitigation measures for such underground atmosphere have also been calculated. © 2014, Springer Science+Business Media New York.


Li W.,China University of Mining and Technology | Zhu Z.,China University of Mining and Technology | Jiang F.,China University of Mining and Technology | Zhou G.,China University of Mining and Technology | Chen G.,China University of Mining and Technology
Mechanical Systems and Signal Processing | Year: 2015

Fault diagnosis of rotating machinery is receiving more and more attentions. Vibration signals of rotating machinery are commonly analyzed to extract features of faults, and the features are identified with classifiers, e.g. artificial neural networks (ANNs) and support vector machines (SVMs). Due to nonlinear behaviors and unknown noises in machinery, the extracted features are varying from sample to sample, which may result in false classifications. It is also difficult to analytically ensure the accuracy of fault diagnosis. In this paper, a feature extraction and evaluation method is proposed for fault diagnosis of rotating machinery. Based on the central limit theory, an extraction procedure is given to obtain the statistical features with the help of existing signal processing tools. The obtained statistical features approximately obey normal distributions. They can significantly improve the performance of fault classification, and it is verified by taking ANN and SVM classifiers as examples. Then the statistical features are evaluated with a decoupling technique and compared with thresholds to make the decision on fault classification. The proposed evaluation method only requires simple algebraic computation, and the accuracy of fault classification can be analytically guaranteed in terms of the so-called false classification rate (FCR). An experiment is carried out to verify the effectiveness of the proposed method, where the unbalanced fault of rotor, inner race fault, outer race fault and ball fault of bearings are considered. © 2014 Elsevier Ltd. All rights reserved.


Guo S.-D.,China University of Mining and Technology
EPL | Year: 2015

We investigate the energy band gap, dielectric functions and thermoelectric properties of Mg2Sn at hydrostatic pressure by using a modified Becke and Johnson exchange potential. It is very interesting that the energy band gap first increases with increasing pressure, and then decreases. The phonon calculations prove that no structural phase transition under the considered pressure is produced. When the pressure reaches 5.6 GPa, the energy band gap attains the biggest value, which is also a critical pressure with the Mg s-character near the high symmetry X-point transforming from the first conduction band to the second one. When the pressure increases to 50.7 GPa, the energy band gap closes, leading to a semiconductor-to-semimetal transition. As the pressure increases, the main peaks of the real and imaginary part of the dielectric functions of Mg2Sn move toward the high-energy region. The Seebeck coefficient and power factor for p-type doping change little with increasing pressure, but for n-type they vary greatly. The change trend of the Seebeck coefficient and power factor for n-type doping as a function of pressure is conic, whose critical pressure is just 5.6 GPa. © CopyrightEPLA, 2015.


Deng Y.-B.,Zhejiang University | Xie K.-H.,Zhejiang University | Lu M.-M.,China University of Mining and Technology | Tao H.-B.,Zhejiang University | Liu G.-B.,Ningbo University
Geotextiles and Geomembranes | Year: 2013

The rate of consolidation by prefabricated vertical drains (PVDs) is closely related to the well resistance, which mainly depends on the discharge capacity of PVDs. According to the existing laboratory tests and field investigations, the discharge capacity of PVDs will decrease with the development of consolidation due to its deformation and siltation and so on. Based on this consideration, in this paper, the discharge capacity was assumed decreased exponentially with time, which resulted in an increase of the well resistance with time during consolidation. Then, a closed-form solution considering the time dependent well resistance for a vertical drain system was developed based on the equal strain condition. Comparisons were presented with some existing solutions for the excess pore water pressure and for the radial average degree of consolidation. The influences of the time dependent well resistance on consolidation rate were then analyzed and the application of the present solution was discussed. © 2012.


Wang E.-Y.,China University of Mining and Technology | Zhao E.-L.,China University of Mining and Technology
International Journal of Rock Mechanics and Mining Sciences | Year: 2013

Based on the stress distribution characteristics and energy dissipation and release theories, a theoretical model of the electromagnetic radiation (EMR) in coal is established. The model is used in conjuction with rock failure process analysis software (RFPA) to numerically simulate the processes of coal/rock deformation and failure, the characteristics of the stress distribution and EMR in the processes, and the effects of the coal compressive strength and loading rate on the EMR. The results show that: (1) the EMR signals generated by coal samples under uniaxial compression increase with stress until the samples fail, and after that the EMR signals decrease rapidly. This is consistent with experimental results and belongs to group-shock type; (2) the EMR signals generated by rock samples under uniaxial compression reach their peaks at the time of main failure, and after that and in initial loading, the signals are weak. that is consistent with experimental results and belongs to main-shock type; (3) the greater the compressive strength of a coal sample is, more time delays its failure results in, and the higher the peak stress becomes; EMR signals generated in the breaking process of coal show an increasing trend. These results indicate that the theoretical model of EMR in coal can be used to study detailed EMR characteristics of coal in complex conditions. © 2012 Elsevier Ltd.


Zhao X.,China University of Mining and Technology | Zhou G.,China University of Mining and Technology
Cold Regions Science and Technology | Year: 2013

Thermal gradient is one of the main features in frozen engineering, especially in artificial frozen wall (AFW) in deep alluvium. This paper investigated the creep behaviors of frozen soil with thermal gradient. A series of uniaxial creep tests were carried out on frozen saturated clay under various thermal gradients and creep stresses by GFC (freezing with non-uniform temperature without experiencing K0 consolidation) method. Two stages were observed during the whole creep process, i.e., instantaneous elastic deformation and decaying creep deformation. Radial creep deformation of ε3 almost increases linearly with an increase in axial creep deformation of ε1, and the slope of ε3-ε1 curve increases as the thermal gradient (or creep stress) increased. Long-term strength decreases as the thermal gradient (or the creep time) increased. Considering the correction equation on thermal gradient, the generalized Kelvin model consisting of one Hooke element and two Kelvin elements has been developed to describe the axial creep deformation. The validity of the model is verified by comparing its calculated results with the results of creep tests under both low and high thermal gradient. It is found that the axial creep deformation behavior of frozen saturated clay can be represented by generalized Kelvin model, and the proposed model reflects thermal gradient effects to the creep deformation well. © 2012 Elsevier B.V.


Jiang Y.-D.,China University of Mining and Technology | Wang T.,China University of Mining and Technology | Zhao Y.-X.,China University of Mining and Technology | Wang C.,China University of Mining and Technology
Zhongguo Kuangye Daxue Xuebao/Journal of China University of Mining and Technology | Year: 2013

Simulations of the stopping process at the face along the hanging wall and the foot wall in the presence of an included fault were respectively done. An interface element with a Coulomb shear model was used to model the interface at the fault. The development of normal and shear stresses at the fault were determined. Movement of the hanging and foot walls and the distribution of abutment pressure in the face coal were estimated. The stress distribution in the fault zone has obvious spatial-temporal features that appear during stoping. Normal stresses show a different sensitivity to mining than do the shear stresses. Normal stress always changed sooner than the shear stress. The fault was more likely to be activated the closer to the face it was located. Different stoping methods would lead to different likelihoods of fault activation. Compared to mining on the hanging wall, mining on the foot wall shows a relatively small affect on the fault. But in the latter case the ratio between shear and normal stresses was larger and fault activation was more likely.


Miao Z.,China University of Mining and Technology | Shi W.,China University of Mining and Technology | Zhang H.,China University of Mining and Technology | Wang X.,Hong Kong Polytechnic University
IEEE Geoscience and Remote Sensing Letters | Year: 2013

Road centerline extraction from remotely sensed imagery can be used to update a Geographic Information System (GIS) database. The common road extraction from high-resolution imagery is based on spectral information only; it is difficult to separate road features from background completely, and a thinning algorithm always results in short spurs which reduce the smoothness of the road centerline. To overcome the aforementioned shortcomings of the common existing road centerline algorithms, this letter presents a new method to extract the road centerline from high-resolution imagery based on shape features and multivariate adaptive regression splines (MARS), in which potential road segments were obtained based on shape features and spectral feature, followed by MARS to extract road centerlines. Two experiments are performed to evaluate the accuracy of the proposed method. © 2004-2012 IEEE.


Kang X.-Q.,China University of Mining and Technology
Journal of Failure Analysis and Prevention | Year: 2016

In this research, a 25Cr2MoVA steel bolt used to assemble a high-pressure steam turbine cylinder in a power generation plant fractured after approximately 23 years of operation. Macrographic and micrographic analysis, scanning electron microscopy techniques, chemical analysis, tensile, impact and hardness testing were used to fully characterize the component and material properties. Based on thorough investigations, it has been identified that mechanical properties of connecting bolt of the cylinder were weakened by bulk ferrite during heat treatment and coarse grain boundaries during long-term use and these induce the bolt fracture under an impact force during the equipment startup process. It is recommended that all bolts in the same situation should be changed, or that high-pressure steam turbines should be carefully operated in order to avoid great impact during maintenance operations, especially during the equipment startup and shut-down process. This research clearly provides guidance for standard-setting committees and contributes to the prevention of similar types of accidents. © 2016 ASM International


Wei Z.,China University of Mining and Technology
IOP Conference Series: Earth and Environmental Science | Year: 2016

Aquifer water abundance evaluation is a highly relevant issue that has been researched for many years. Despite prior research, problems with the conventional evaluation method remain. This paper establishes an aquifer water abundance evaluation method that combines fuzzy evaluation with a comprehensive weighting method to overcome both the subjectivity and lack of conformity in determining weight by pure data analysis alone. First, this paper introduces the principle of a fuzzy-comprehensive weighting method. Second, the example of well field no. 3 (of a coalfield) is used to illustrate the method's process. The evaluation results show that this method is can more suitably meet the real requirements of aquifer water abundance assessment, leading to more precise and accurate evaluations. Ultimately, this paper provides a new method for aquifer water abundance evaluation. © Published under licence by IOP Publishing Ltd.


Chen S.,China University of Mining and Technology | Chen S.,Ningbo University of Technology | Ying P.,China University of Mining and Technology | Wang L.,Ningbo University of Technology | And 2 more authors.
Applied Physics Letters | Year: 2014

In this work, we reported the temperature-dependent field emission (FE) of flexible n-type SiC nanoneedles grown on the carbon fabric substrates via pyrolysis of polymeric precursor. The obtained n-type SiC nanoneedles with clear and sharp tips were incorporated by N dopants with a uniform spatial distribution. The FE behaviors of n-type SiC nanoneedles exhibit a strong dependence on the temperatures. Their turn-on fields and threshold fields decrease from 1.37 to 0.67V/μm and 1.87 to 0.96V/μm with the temperature raised from room temperature (RT) to 400°C, respectively. The measured current emission stabilities of the n-type SiC nanoneedles under RT and 200°C are ∼7.7% and 14.1%, respectively. The temperature-dependent FE characteristics could be attributed to the reduction of the work function of n-type SiC nanoneedles induced by the raise of temperatures and the incorporated N dopants. © 2014 AIP Publishing LLC.


Guo S.-D.,China University of Mining and Technology
Journal of Magnetism and Magnetic Materials | Year: 2015

Objective: Half-metallic ferromagnetism plays a major role in high-performance spintronic applications due to its 100% spin-polarization. So, it is very necessary to search better half-metallic ferromagnets with large magnetic moment and being compatible with current semiconductor technology. Methods: We study cubic Eu4O3N on the basis of state-of-the-art first-principles calculations by using generalized gradient approximation plus U method. Results: It is found that the Eu4O3N is a half-metallic ferromagnet with a half-metallic gap of 376 meV and the large Eu ion magnetic moment up to about 7 μB. The structural and ferromagnetic stability are proved by mechanical stability criterion and magnetic energy differences, respectively. The half-metallic properties are also stable against the isotropic strain, volume-conservative tetragonal strain and rhombohedral distortion. For the choice of U between 4 and 8 eV, the Eu4O3N still is half-metallic ferromagnet. Conclusion: This provides a new idea for searching new half-metallic ferromagnetism by f electrons. Practical implications: If the Eu4O3N was experimentally synthesized with half-metallic properties, it should be used to design high-performance spintronic devices. © 2015 Elsevier B.V. All rights reserved.


Ding S.,China University of Mining and Technology | Zhu H.,China University of Mining and Technology | Jia W.,China University of Mining and Technology | Su C.,China University of Mining and Technology
Artificial Intelligence Review | Year: 2012

In research of pattern recognition, we always want to achieve the correct classification rate according to the characteristics required. Feature extraction greatly affects the design and performance of the classifier, and it is one of the core issue of PR research. As an important component of pattern recognition, feature extraction has been paid close attention by many scholars, and currently has become one of the research hot spots in the field of pattern recognition. This article gives a general discussion of feature extraction, includes linear feature extraction and nonlinear feature extraction, and introduces the frontier methods of this field, at last discusses the development tendency of feature extraction. © Springer Science+Business Media B.V. 2011.


Guo S.-D.,China University of Mining and Technology
European Physical Journal B | Year: 2015

We investigate the electronic structures and magnetic properties of the ferrimagnetic double-perovskites Sr2XReO6 (X = Cr, Mn, Fe, Ni) by using Tran and Blaha’s modified Becke and Johnson exchange potential. The calculated results show that Sr2XReO6 (X = Cr, Fe) are half-metals, and Sr2XReO6 (X = Mn, Ni) are insulators, which is in accordance with the experimental results. By using the ionic picture, we explain the trend in the density of states and total magnetic moment with X changing from Cr to Ni. We find that the insulating property is associated with X2 +, while the metallic character is associated with X3 +. The Re t2g splitting in the minority channel leads to insulativity of Sr2XReO6 (X = Mn, Ni), and the Re t2g splitting of Sr2MnReO6 is caused by lattice distortion, while Sr2NiReO6’s splitting is due to the heavier atomic mass of Ni. When spin-orbit coupling is included, the spin polarization of Sr2XReO6 (X = Cr, Fe) drifts off 100%, and the related gaps of Sr2XReO6 (X = Mn, Ni) become narrow. The spin-orbit coupling results in a significant increase in the total magnetic moment due to an unquenched Re orbital moment. Our calculated energy band structures show that Sr2MnReO6 is a spin gapless semiconductor, which can realize fully polarized spin-down electrons and spin-up holes. © 2015, EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.


Cao W.,China University of Mining and Technology | Cao W.,Xuzhou Institute of Technology | Zhang Y.,China University of Mining and Technology
Ecological Engineering | Year: 2014

The present experiment tested various EFBs for the purification of hypereutrophic waters under batch and continuous flow conditions. A conventional plant-only EFB (EFB-PO) was used as the control system and compared to EFBs using either rice straw (EFB-RS) or plastic filling (EFB-PF) as a substrate for microorganisms. Under the batch condition, the mean removal rates of the EFB-RS for total nitrogen (TN), ammonium nitrogen (NH4 +-N), and nitrate nitrogen (NO3 --N) were, respectively, 76.94, 93.50, 93.18% after 2 days, which represent increases of 43.94%, 19.83%, 75.24% and 34.76%, 24.67%, 34.54% over the same values for EFB-PF and EFB-PO, respectively. The number of total bacteria, nitrifying bacteria, and denitrifying bacteria in the rice straw system, as well as the total amount of biomass, was significantly greater than in the plastic filling system. The results of the continuous flow experiment indicated that the mean removal rates of TN, NH4 +-N, and NO3 --N for EFB-RS and EFB-PF were, respectively, 72.21%, 88.88%, and 80.41%, and 51.85%, 86.23%, and 58.62% when the hydraulic retention time (HRT) was 24h. Relative to the EFB-PF system, the EFB-RS system exhibited a lower accumulation of NO2 --N concentration. © 2013 Elsevier B.V.


Meng Q.,China University of Mining and Technology
Industrial Lubrication and Tribology | Year: 2014

Purpose - The aim of this work is to reveal the temperature rise characteristics of the new designed disc during a braking process. In underground coal mines, the highest temperature of the disc brake used for inclined downward belt conveyors should be 150 to prevent gas explosion during a braking process. To meet the requirements, a new type of disc was designed. Design/methodology/approach - By using ANSYS software, the disc surface and interior temperature rise variations, effect of braking time and running speed on temperature rise are analyzed numerically. Findings - The results show that the new designed disc can meet the coal mines' requirements well, during the braking process the disc surface temperature increases at first and then decreases, there is an obvious temperature gradient in the axial direction; when running speed increases to two times of the rated one, the highest temperature nearly reaches 150; and a prolonged braking time can decrease the highest temperature effectively. Research limitations/implications - It indicates that the disc brake should act as earlier as possible to slow down the belt conveyor when overspeed occurs; and when the running speed increases to two times of the rated one, the braking time must be prolonged to prevent gas explosion. Originality/value - Research findings of this paper provides theoretical basis for the practical applications of the disc brake used for inclined downward belt conveyor. © Emerald Group Publishing Limited.


Liu Z.,China University of Mining and Technology
Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology) | Year: 2014

To study the subgrade humidity field distribution with different compaction models, 4 subgrade numerical models with different compaction conditions were established. Through analyzing tow-dimensional infiltration rainfall test results, the influences of different compaction models on the humidity disturbed zone distributions, the extended distances, the subgrade humidity values and gradients were examined. The mechanisms behind these findings were explained. The results show that humidity disturbed zone appears after rainfall infiltration and it can be divided into front and back zone. The characteristics of back zone include the larger humidity and the smaller gradient, while the front zone just has the opposite conditions. The extended distances and humidity values of the disturbed zone decrease linearly with the increase of subgrade compaction degree. The humidity gradient of the front zone increases linearly with the increase of subgrade compaction degree. Since the vertical component of the rainfall infiltrating velocity vector is considerably larger than the horizontal one, the subgrade humidity of a deep layer decreases significantly with the increase of upper subgrade compaction in unsaturated disturbed zones, which is also affected by the composition of subgrade compaction zones.


Xia Y.H.,China University of Mining and Technology | Xu X.L.,China University of Mining and Technology
Applied Mechanics and Materials | Year: 2014

In the application of ground penetrating radar (GPR) to detect roadbed diseases, this paper designs a kind of auxiliary system for GPR to solve the problems,such as how to obtain precise location of the diseases and how to explain the causes of the roadbed disease more reasonably. Combined with the actual test results, this paper discusses the feasibility and superiority of the auxiliary system in quality inspection of highway roadbed. © (2014) Trans Tech Publications, Switzerland.


Du Y.,China University of Mining and Technology | Du Y.,University of Twente | Schuur B.,University of Twente | Samori C.,University of Bologna | And 2 more authors.
Bioresource Technology | Year: 2013

Lipids from algal biomass may provide renewable fuel and chemical feedstock in large quantities. The energy intensity of drying and milling of algae prior to extraction and of solvent recovery afterwards is a major obstacle. The objective is to use switchable solvents to extract oil directly from wet microalgae slurries without the need for drying and milling, and subsequently recover the extracted oil and solvent by simple phase splitting, using CO2 as trigger. In this work secondary amine solvents were investigated for lipids extraction, polarity switching and phase splitting ability upon contacting with CO2. For strain Desmodesmus sp. extraction yields from the wet algal slurries, with and without cell disruption, were comparable with Bligh & Dyer method yields. Oil and solvent recovery via phase separation was realized by CO2 induced phase splitting, making secondary amines a candidate for further development of an energy efficient lipid extraction technology for non-broken microalgae. © 2013 Elsevier Ltd.


Xu R.F.,China University of Mining and Technology | Farrall A.J.,University of Kent | Young P.R.,University of Kent
IEEE Microwave and Wireless Components Letters | Year: 2014

This letter provides an approximate analysis of a slotted substrate integrated waveguide with periodic loading elements using the transverse resonance technique. The technique is used to design a travelling wave attenuator whereby pin diodes are capacitively coupled to the waveguide slot. By changing the bias, and therefore loading resistance, a very constant, variable attenuation is produced over the waveguide band. © 2013 IEEE.


Zhang Y.,China University of Mining and Technology | Gong D.-W.,China University of Mining and Technology | Zhang J.-H.,China University of Mining and Technology
Neurocomputing | Year: 2013

In many real-world applications, workspace of robots often involves various danger sources that robots must evade, such as fire in rescue mission, landmines and enemies in war field. Since it is either impossible or too expensive to get their precise positions, decision-makers know only their action ranges in most cases. This paper proposes a multi-objective path planning algorithm based on particle swarm optimization for robot navigation in such an environment. First, a membership function is defined to evaluate the risk degree of path. Considering two performance merits: the risk degree and the distance of path, the path planning problem with uncertain danger sources is described as a constrained bi-objective optimization problem with uncertain coefficients. Then, a constrained multi-objective particle swarm optimization is developed to tackle this problem. Several new operations/improvements such as the particle update method based on random sampling and uniform mutation, the infeasible archive, the constrained domination relationship based on collision times with obstacles, are incorporated into the proposed algorithm to improve its effectiveness. Finally, simulation results demonstrate the capability of our method to generate high-quality Pareto optimal paths. © 2012 Elsevier B.V.


Zhu S.,China University of Mining and Technology | Shen Y.,Huazhong University of Science and Technology
Neural Networks | Year: 2013

This paper analyzes the robustness of global exponential stability of stochastic recurrent neural networks (SRNNs) subject to parameter uncertainty in connection weight matrices. Given a globally exponentially stable stochastic recurrent neural network, the problem to be addressed here is how much parameter uncertainty in the connection weight matrices that the neural network can remain to be globally exponentially stable. We characterize the upper bounds of the parameter uncertainty for the recurrent neural network to sustain global exponential stability. A numerical example is provided to illustrate the theoretical result. © 2012 Elsevier Ltd.


Zhu S.,China University of Mining and Technology | Shen Y.,Huazhong University of Science and Technology
Neurocomputing | Year: 2013

This paper analyzes the robustness of global exponential stability of recurrent neural networks subject to parameter uncertainty in connection weight matrix. Given a globally exponentially stable recurrent neural network, the problem to be addressed herein is how much parameter uncertainty in the connection weight matrix that the neural network can remain to be globally exponentially stable. We characterize the upper bounds of the parameter uncertainty for the recurrent neural networks to sustain global exponential stability. A numerical example is provided to illustrate the theoretical result. © 2012 Elsevier B.V.


Wang B.,China University of Mining and Technology | Gu X.,China University of Mining and Technology | Zhao Y.,China University of Mining and Technology | Qiang Y.,China University of Mining and Technology
Applied Surface Science | Year: 2013

AgBr/Ag3PO4 hybrid microstructures were synthesized by a facile method. These hybrids exhibited the enhanced photocatalytic performance for degradation of rhodamine B (RhB) under the visible light illumination. Additionally, the effect of AgBr content on the recyclability of the hybrid was investigated. The best recyclability of the hybrid was realized in the samples containing 50% AgBr. Such a behavior might be attributed to the increased high active sites and suitable energy band structure. The possible mechanism was discussed. © 2013 Elsevier B.V. All rights reserved.


Based on a series of triaxial compression experiments using hollow sandstone specimens with various hole diameters (d = 0, 11, 15 and 26 mm), the deformation, peak strength and crack damage behavior of hollow sandstone specimens under different confining pressures are investigated. The experimental results show that the Young's modulus of hollow sandstone only depends on the confining pressure and is not affected by hole diameter in the tested range of d = 0–26 mm. Two types of methods used to confirm the elastic modulus and Poisson's ratio of rock material are proposed to evaluate the triaxial deformation characteristics of hollow sandstone. The effects of confining pressure and hole diameter on the Poisson's ratio and peak strain of hollow sandstone are analyzed. The peak strength and crack damage parameters of hollow sandstone depend on not only the confining pressure (σ3) but also the hole diameter. Under uniaxial compression, the peak strength and crack damage threshold (σcd) of hollow sandstone are independent of hole diameter, whereas the triaxial compressive strength of hollow sandstone decreases linearly with increasing hole diameter. The peak strength and crack damage threshold of hollow sandstone increase with increasing confining pressure, which can be better described by the nonlinear Hoek-Brown criterion than by the linear Mohr-Coulomb criterion. Furthermore, the sensitivity of the crack damage threshold of hollow sandstone to hole diameter is lower than that of peak strength on hole diameter. The concluding remarks can be used to improve the stability and safety of deep underground engineering. © 2016 Elsevier B.V.


Liu W.,China University of Mining and Technology | Wang Z.,Henan Institute of Science and Technology
Measurement Science and Technology | Year: 2010

Precision three-dimensional measurement of large-scale workpiece frequently involves the combination of several different types of measurement systems; they may be laser tracker, total station, laser scanner and portable coordinate measuring machines, etc. In order to provide optimization measuring results, a new method, called the isolated variable sub-system (IVSS), has been developed to deal with variable coupling that fully takes into account the uncertainty of each measurement individual system. The IVSS method is a combination of pattern search and