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).


Yu H.,China University of Mining and Technology | Chen H.,China University of Mining and Technology | Long R.,China University of Mining and Technology
Resources Policy | Year: 2017

Many researchers have confirmed that most accidents occur during night shifts, but coal mine production in China is an exception. The frequency of accidents during day shifts is significantly higher than that of night shifts. We refer to this as a safety paradox. This study collected 1870 instances of the worst fatal accidents in Chinese coal mines from 2002 to 2013, which in total accounted for the deaths of 13,477 miners. We mainly employed frequency analysis to describe the imbalance in accident risks between day shifts and night shifts. Then we deployed a reaction time test and “psychometric fatigue assessment scale” to measure the differences in mental fatigue between day-shift and night-shift workers. In further, we analyzed the supervision records of the coal mines and found that the level of supervision was more intensive during night shifts. Based on these analyses, we put forward “the pendulum effect of mental fatigue” as an explanation for the safety paradox experienced in Chinese coal mines. Lastly, we suggest possible solutions that coal mine managers and the government policy-makers could undertake. © 2017 Elsevier Ltd


Liu F.,China University of Mining and Technology | Lyu T.,China University of Mining and Technology | Pan L.,China University of Mining and Technology | Wang F.,China University of Mining and Technology
Energy Policy | Year: 2017

With the development of clean coal technology, modern coal-fired power plants have achieved the similar emission standards as gas power plants. However, due to the impressions of high pollution and high emission in traditional coal-fired power plants, such projects are often opposed by local residents, which hinder the promotion of this technology. This manuscript aims to investigate public attitudes toward these projects and to analyze the influencing mechanisms of the factors of public support. The conceptual model was built with sense of place, trust and environmental attitude as the independent variables, benefit and cost perceptions as the mediating variables and public support as the dependent variable. The model was tested and modified by structural equation modelling. The results revealed that sense of place had a slight indirect impact (−0.043) on public support through benefit perception, whereas trust had a direct impact (0.332) on public support and indirect impacts (0.298) through benefit and cost perceptions. Environmental attitude had indirect impacts on public support through benefit perception (0.180) and cost perception (−0.115). In addition, policy suggestions on decision-making, project publicity and compensation strategy are proposed to enhance public support for similar projects. © 2017


Chang M.,China University of Mining and Technology | Cui Y.,China University of Mining and Technology
Chemical Engineering Transactions | Year: 2016

Carbon monoxide (CO) is a commonly used indicator gas to predict the risk of coal spontaneous combustion. However, the occurrence of primal CO in coal seam may result in error of prediction. Therefore, identifying the primal CO in coal seam is crucial to improve the accuracy of coal spontaneous combustion prediction. This paper conducts a laboratory experiment to research the regularities of primal CO desorption. Four analysis factors are introduced to represent the CO emission characteristics in different desorption stages. The result indicates that CO generated by different coal samples' oxidation has big differences. Ambient temperature has little effect on CO initial emission concentration. CO concentration in the first one and first ten desorption hour increases regularly with the increase of crushing time, primal CO cannot be ignored especially in high temperature coal mines. Copyright © 2016, AIDIC Servizi S.r.l.


Li C.,China University of Mining and Technology | Zhao J.,Jiangsu University
Journal of Environmental Engineering and Landscape Management | Year: 2017

Understanding and predicting of the urban growth process and its impact have become increasingly important for decision making toward sustainable development. In this paper, we presented a cellular automata model to assess the consequence of future urban growth. The hybrid calibration method combining logistic regression with trial-and-error was applied to estimate the parameters. The study proposed the integration method of Multi-Criteria Evaluation and Analytic Hierarchy Process that can be utilized to effectively translate the qualitative descriptions of scenarios into quantitative spatial analysis. Finally, the comparison of the different scenarios provided an insight into the impacts of different urban development strategies on landscape patterns. The result indicates that CA model can be effectively connected with the urban decision making processes. The moderate development scenario could be considered as the best one in achieving the objectives of compact urban form, good residential environment, as well as environmentally and economically efficient development. © 2017 Vilnius Gediminas Technical University (VGTU) Press.


Liu T.,Xuzhou Institute of Technology | Hou J.-H.,Xuzhou Institute of Technology | Peng Y.-L.,China University of Mining and Technology
Environmental Progress and Sustainable Energy | Year: 2017

In this paper, we made attempt to desulfurize the coal collected from Yihai coalfield of Qinghai province in China contains high total sulfur content (4.97% by mass) and high organic sulfur content (3.37% by mass). The high sulfur coal sample was subjected to desulfurization by using a new bacterium isolated from the native coal mine site. The molecular identification of the 18S rRNA gene showed that the native bacterium was Aspergillus sp., denoted as DP06, and it is reported first time for the capability to remove about 47% of total sulfur from the coal. To improve biodesulfurization performance, the effect of various parameters such as medium pH, pulp density, incubation time, and incubation temperature on the desulfurization was investigated and the optimal values were found as pH 5.0, 5% of pulp density, 8 days, and 35°C, respectively. Final total sulfur content of the desulfurized coal with DP06 was reduced to 2.63% (organic sulfur 1.45% + pyritic sulfur 0.53% and 0.65% of sulfate sulfur). Collaborative treatment high sulfur coal sample by using native bacterium DP06 and Thiobacillus ferrooxidans was studied and demonstrated 59% of total sulfur removed from the coal sample. Results of analytical characterization have indicated that the treatment of high sulfur coal with native bacterium DP06 has caused the increase in calorific value from 6329 cal/g to 6521 cal/g, but the ash content of coal was eliminated. © 2016 American Institute of Chemical Engineers Environ Prog, 36: 595–599, 2017. © 2016 American Institute of Chemical Engineers Environ Prog


Xu P.,China University of Mining and Technology | Yang S.-Q.,China University of Mining and Technology
Arabian Journal of Geosciences | Year: 2017

A constitutive model for fissured rock mass is established based on the deformation characteristics of microcracks under compression. The method to determine the model parameters is given. Comparative analyses between the proposed model and experimental results of siltstone indicate that this model can describe the whole process from the initial state to failure state of fissured rock mass well; this model can also simulate the initial phase in the process of fissured rock under compression well. At the same time, this model can also reflect the property of strain softening as well as the damage evolution process. Compared with previous models, this model is better able to capture the general trend which is observed experimentally. The strain energy and damage revolution of fissured rock under compression are also discussed; and the proposed model is capable of predicting the energy and damage behavior, which are in reasonably agreement with the experimental observations. © 2017, Saudi Society for Geosciences.


Dou G.,Boston University | Dou G.,China University of Mining and Technology | Goldfarb J.L.,Boston University
Fuel | Year: 2017

The ability to in situ upgrade pyrolysis biofuels, together with the production of a value-added byproduct from the solid biomass residue, would reduce the economic and environmental costs of the integrated biorefinery. In the present work, biomass samples (mango pits and pineapple plants) were immersed in Fuller's Earth (bentonite clay) suspensions. Pyrolysis at low temperatures (290–350 °C) showed that the incorporation of Fuller's Earth into both biomasses increases the amount of H2, CH4, C2H2, C2H4, and C2H6 evolved as compared to raw biomass. The biomasses’ behavior diverges in terms of bio-oil and biochar quality. For mango pit, pretreatment with Fuller's Earth increased desirable compounds such as furans and hexanes, whereas for pineapple plant oxygenated and high molecular weight compounds increased with pretreatment. While surface areas of both biomasses increased with incorporation of bentonite clay, the mango pit saw a significant increase in adsorption capacity and rate of methylene blue removal from water, whereas the pineapple plant adsorption rate decreased with pretreatment; capacity increased at low pyrolysis temperature and decreased at high temperature. While incorporation of Fuller's Earth increased the thermal energy required to heat the impregnated mixtures to pyrolysis temperature, a distributed activation energy model analysis shows that activation energy of pyrolysis was virtually the same for impregnated and raw biomass samples, suggesting that this may be either a thermally catalytic or chemically catalytic effect. Thus, incorporation of bentonite into some biomasses may represent positive benefits in terms of in situ upgrading bio-fuels and hybrid biochars produced at lower pyrolysis temperatures. © 2017 Elsevier Ltd


Yang K.,China University of Mining and Technology | Hao J.,China University of Mining and Technology | Wang Y.,China University of Mining and Technology
ECCE 2016 - IEEE Energy Conversion Congress and Exposition, Proceedings | Year: 2016

A hybrid method based on artificial neural networks (ANNs) and Quasi-Newton algorithm is proposed to generate the switching angles for selective harmonic elimination (SHE), which makes a compromise among the memory consumption, executing efficiency and the solution precision. Unlike the other ANNs based methods which use ANNs to directly give the final switching angles, this hybrid method just uses ANNs to give the initial values, which lowers the precision requirement on training the ANNs, so, the number of the neurons can be reduced and less on-chip memories are required. Then, the Quasi-Newton algorithm is used to solve the exact switching angles from the initial values given by the ANNs, which guarantees the solving efficiency and the solution precision. The case of 11-level staircase modulated converter is studied by using the single-layer back-propagation (BP) neural networks. The trained neural networks have only 9 neurons in the hidden layer and the output initial values can meet the convergent requirement of the Quasi-Newton algorithm in the full range of modulation index. The total executing time is about 70ms on a STM32F407 microcontroller, as the executed code is automatically generated by MATLAB, the executing time could be further reduced if the code is manual optimized. Experiment results are also shown to verify the correctness of the switching angles generated by the proposed hybrid method. © 2016 IEEE.


Xu Z.,China University of Mining and Technology | Jiang H.,China University of Mining and Technology
Journal of Computational and Theoretical Nanoscience | Year: 2016

In recent years, with the continuous development of urban traffic and ecological environment, study on enhancing urban function and optimizing space has attracted extensive attention. Based on support vector machine algorithm, this paper solves the problems about reasonableness and fairness, two quantitative indicators in the rating of the sustainable development of urban traffic and ecological environment. This paper constructs an evaluation system for the sustainable development of urban traffic and ecological environment based on support vector machine through a modern algorithm, which can evaluate the development status of modern cities in real time and conduct warning processing if necessary, thus improving the scientificity of urban planning and development and providing new reference for the evaluation system for the sustainable development of urban traffic and ecological environment. © Copyright 2016 American Scientific Publishers All rights reserved.


Jiang D.-H.,Xuzhou Institute of Technology | Jiang D.-H.,China University of Mining and Technology
Journal of Computational and Theoretical Nanoscience | Year: 2016

Traditional genetic algorithm exists disadvantages such as easy to premature convergence, low efficiency optimization and precision etc. Both the fitness value function and diverse group of traditional genetic algorithm has been improved to avoid the premature fall into traditional genetic algorithm local optimal solution, broadening the optimization space. The improved genetic algorithm is applied to optimize the design of building structures, through the establishment of minimum weight objective optimizationmodel to solve the cross-sectional dimension with stress constraints and the constraints of structural optimization with discrete variables, and then with standard genetic algorithm to optimize the design of the results a comparative validation results show that: The improved genetic algorithm than the standard genetic operators fewer iterations, the convergence performance was significantly better, really improved genetic algorithm applied to structural optimization calculation speed and optimization results. © 2016 American Scientific Publishers All rights reserved.


Han F.,China University of Mining and Technology | Zhang Y.,Tianjin Academy of Environmental science
Journal of Computational and Theoretical Nanoscience | Year: 2016

Environmental carrying capacity of Chinese cities is of great significance in the social prediction and social management. The change regulation of the environmental carrying capacity in Chinese cities is various from year to year. Previous research use the multiple linear regression (MLR) method to develop a series of prediction models for the prediction of environmental carrying capacity. However, results are not accurate enough. It is highly difficult to measure the impacts of different independent variables because of the randomness of social science. Therefore, the MLR approach may not quite suitable for adapting the actual applications. Here, we present two strong models in order to improve the prediction precision of the environmental carrying capacity of Chinese cities. Artificial neural networks (ANNs) and grey model GM (1, 1) prediction is proposed. We use general regression neural network (GRNN) and multi-layer feed-forward neural network (MLFN) models as the trained ANN models. Best net search approach is used for searching the most suitable ANN model according to the RMSE and training time. GM (1, 1) model is proposed using the number sequence of the year, which is dependent to various independent variables. Results show that both the ANNs and GM (1, 1) can be effectively used for the prediction of the environmental carrying capacity of Chinese cities. Under different conditions can we decide to use a certain suitable prediction model. Copyright © 2016 American Scientific Publishers All rights reserved.


Hai P.,China University of Mining and Technology | Cheng X.,China University of Mining and Technology
50th US Rock Mechanics / Geomechanics Symposium 2016 | Year: 2016

In Western China, mining area has the characteristics of thin bedrock and shallow-buried. The mine excavation and deep mineral production will change the stability of initial rock mass structure and the in-situ stress field. The rock fractures are fully developed and even result in a completely broken state of rock. To study the volume effect on the water-sand seepage characteristics in broken rocks, the seepage experiments were performed by a new seepage system of water-sand mixture, which was designed based on the CMT5305 electronic universal testing machine. The results showed that when the initial porosity of broken rock kept constant, the sand filterability of broken rock increased with the thickness of rock sample; the influence of the thickness of rock sample on the quantity of filtering sand increased with the initial porosity of broken rock; the filterability of broken rock increased to a constant value with the rock sample thickness; the influence of rock sample thickness on the water seepage was not obvious, and the initial porosity had a greater effect on the water-sandstone seepage characteristics than the rock sample thickness.


Xu J.,China University of Mining and Technology | Li F.,China University of Mining and Technology
Journal of Materials in Civil Engineering | Year: 2017

The concrete permeability at low deformation of the chlorine ion is closely related to the porosity of concrete. Under stress, the porosity of concrete will change; at the same time, the chloride ion diffusion coefficient will also change. In this study, at the microscale, concrete was simplified as solid phase (zero porosity) and pore (the sum of various scales pores) of two phase composite materials. Based on the theory of elasticity, an analytical model was developed, and the quantitative relationship between the current porosity of concrete and the diffusion coefficient of the chloride ion, as well as the external equivalent stress, were evaluated. The primary parameters in the analytical model were the solid phase elastic moduli and the solid phase Poisson's ratio, the initial porosity of the concrete and the external equivalent stress. The good agreement between the proposed model and the available test data illustrated the proposed model's reliability and accuracy. The proposed model showed that the chloride diffusion coefficient or current porosity of concrete at low deformation levels decreases with the increase in compressive stress and increases with the increase in tensile stress. However, the initial porosity of concrete was still the primary factor influencing the chloride ion diffusion. © 2016 American Society of Civil Engineers.


Tang C.,China University of Mining and Technology | Tang C.,Beijing Urban Construction Exploration & Surveying Design Research Institute Company | Shao L.,China University of Mining and Technology
Communications in Computer and Information Science | Year: 2017

Development and spatial ability are the main content of the quantitative distribution characteristics of rural residential areas. This quantitative study of Jincheng River Basin rural settlements distribution as an example, discusses the potential effect on spatial distribution of rural settlements distribution in the main influence factor, using weights of evidence method to quantify the influence degree of each factor, based on the rural residential space distribution characteristics of the quantitative evaluation. According to the model, select the related to the distribution and residential elevation, slope, road, water, per capita income, residential area, etc. factor as evidence layers, through the calculation of evidence layers distribution of rural settlements in the study area posterior probability, has carried on the quantitative evaluation to the whole study area, residential distribution. The study found that for the distribution of rural settlements in the study area and the factors of influencing the influencing sequence: slope > road > height > system > farmers per capita net income > per capita residential covers an area of, and the factors and the residents point was positively correlated; in the study area rural residential space layout need optimization and adjustment; the means of GIS can be effective to multi-source heterogeneous data for rapid optimization and comprehensive analysis and the forecast evaluation results in a quantitative way represented, effectively promote the multiple determinants of complex model, prediction and evaluation from qualitative analysis to quantitative development. © Springer Nature Singapore Pte Ltd. 2017.


Zhao W.,China University of Mining and Technology | Zhu B.,China Electric Power Research Institute
Structural Concrete | Year: 2017

This paper presents basic parameters test and an efficient numerical model for the bond between reinforcing bars and concrete after elevated temperatures. The chemical adhesive and friction coefficient are measured by self-designed setups, and the variation law of the parameters is summarized. In the 3D modeling, bar-to-concrete interface has been modeled by means of an explicit discretization of the bar ribs. Surface-to-surface contact pair elements are employed for the interface, and the tangential contact behavior is elastic-plastic with a Coulomb-type friction model. Comparison between experimental and numerical results shows that the proposed model describes the behavior of steel bar relatively well in the pull-out process after elevated temperatures. The 3D modeling makes up some deficiencies of macro pull-out test, such as the detailed stress distributions and crack patterns. © 2017 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin.


Kumar A.,National Institute of Technology Jamshedpur | Kumar S.,National Institute of Technology Jamshedpur | Yan S.-P.,China University of Mining and Technology
Fundamenta Informaticae | Year: 2017

In this article, improved residual power series method (RPSM) is effectively implemented to find the approximate analytical solution of a time fractional diffusion equations. The proposed method is an analytic technique based on the generalized Taylor's series formula which construct an analytical solution in the form of a convergent series. In order to illustrate the advantages and the accuracy of the RPSM, we have applied the method to two different examples. In case of first example, different cases of initial conditions are considered. Finally, the solutions of the time fractional diffusion equations are investigate through graphical representation, which interpret simplicity, accuracy and practical usefulness of the present method.


Chang P.,China University of Mining and Technology | Qin Z.,Key Laboratory of Coal Processing and Efficient Utilization
International Journal of Electrochemical Science | Year: 2017

In this paper, a novel kind of activated carbon foam (ACF) electrode for electric double layer capacitors (EDLCs) was prepared by a KOH activation procedure on primary carbon foams synthesized via foaming of loose medium component (LMC) which was separated from raw coal by extraction and back-extraction processes and then studied electrochemically using cyclic voltammetry. With the aim of exploring the optimum experimental conditions, the influences of process variables, such as foaming temperature, activation temperature, activation time and KOH/carbon mass ratio on specific capacitance of ACFs were investigated. The morphology, structure and textural properties of the optimum ACF were characterized with N2 adsorption technique, Raman spectrometer, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectrometer. The electrochemical behaviors were analyzed by cyclic voltammetry, galvanostatic charge-discharge cycling and electrochemical impedance spectroscopy. The obtained results show that under the optimum experimental conditions, the sample possesses the specific surface area of 3526.31m2 g-1, total pore volume of 1.972cm3 g-1 and exhibits the highest initial specific capacitance of 204.17F g-1 at current density of 1A g-1 in 6M KOH solution. It shows excellent cycling stability with a capacitance retention of 97.9% after 3000 charge/discharge cycles at current density of 1A g-1, promising its practical application in EDLCs. Thus, the favorable capacitive performances make the ACFs act as a new kind of carbonaceous electrode material for high-power supercapacitors. © 2017 The Authors.


Zhang J.,Heilongjiang University | Li Y.,Heilongjiang University | Li Y.,China University of Mining and Technology
International Journal of Mining Science and Technology | Year: 2017

Ultrasonic vibrations in coal lead to cavitation bubble oscillation, growth, shrinkage, and collapse, and the strong vibration of cavitation bubbles not only makes coal pores break and cracks propagate, but plays an important role in enhancing the permeability of coal. In this paper, the influence of ultrasonic cavitation on coal and the effects of the sonic waves on crack generation, propagation, connection, as well as the effect of cracks on the coal permeability, are studied. The experimental results show that cracks in coal are generated even connected rapidly after ultrasonic cavitation. Under the effect of ultrasonic cavitation, the permeability increases between 30% and 60%, and the number of cracks in coal also significantly increased. Numerical experiments show that the effective sound pressure is beneficial to fracture propagation and connection, and it is closely related to the permeability. Moreover, the numerical simulations and physical experiments provide a guide for the coal permeability improvement. © 2017.


Zhang W.,China University of Mining and Technology | Sun Q.,China University of Mining and Technology | Zhu S.,China University of Mining and Technology | Wang B.,China University of Mining and Technology
Applied Thermal Engineering | Year: 2017

This paper experimentally studied the changes in mechanical and porous characteristics of limestone heated to high temperature (up to 600 °C). The results showed that ① 200 °C and 500 °C are two special temperature point of limestone under the high temperature effect, and the most mechanical and pore parameters change a lot before and after them; ② Below 200 °C, the mechanical and porous characteristics of limestone samples hardly change; ③ In 200–500 °C, the cumulative pore volume, porosity, and pore volume fractal dimension rapidly increase, among which, the porosity increases by about 900%; the peak strength and elastic modulus suddenly decrease by 31.2%, and the peak strain sharply rises by 65.4%; ④ In 500–600 °C, the porous parameters are relatively stable; the peak strength slowly decreases, while the peak strain continuously increases; the elastic modulus continues to decline quickly, the Poisson's ratio drops suddenly, and the hardness decreases from mid-hard to soft. This research is of significance for the variation of physical and mechanical properties in response to thermal treatment of the rock. © 2016 Elsevier Ltd


Wang R.,Jiangsu University | Zhao J.,China University of Mining and Technology
Sustainable Cities and Society | Year: 2017

Although previous works concluded that demographic variables of observers have strong influence on landscape preference, the questions of “which demographic characteristic(s) has(have) greater effects on preference than others” and “what are the features of a landscape preferred by each of the demographic groups” are not answered clearly up to now. This study aims at answering the two questions through a visual preference assessment with 482 laypersons as respondents. The main results include: (a) education level and gender of respondents have a significantly influence on preference assessment; (b) “naturalness”, “growth status of plant” and “elements except plant” are the reliable predictors for the landscape preference of male; for female, the significant predictors are “degree of plant maturation” and “number of colors”, and (c) for the landscape preference of observers with elementary education, the significant predictors are “growth status of plant”, “safety” and “degree of plant maturation”; the observers with middle education and college education have the same predictors: “growth status of plant” and “number of colors”; and “naturalness” and “degree of plant maturation” are the predictors of participants with post graduate education. At last the practical implications of the results are discussed. © 2016 Elsevier Ltd


Li C.,China University of Mining and Technology | Zhao J.,Jiangsu University | Xu Y.,TU Dortmund
Sustainable Cities and Society | Year: 2017

In the context of rapid urbanization, the comprehensive analysis of urbanization process, urban expansion effects and the underlying driving factors have become increasingly crucial for providing support to the land management and urban planning decision. This study explores spatial metrics, geographically weighted regression (GWR), and cellular automata (CA) model, with a case study in Xuzhou city, China, to analyze the urbanization process. Spatial metrics were applied for quantifying the urban spatial patterns. The spatiotemporally varying effects of urban expansion on spatial patterns were further investigated using GWR. By involving natural and socioeconomic variables, CA model was applied to examine the relationship between driving factors and urban expansion. The results indicate that the spatial patterns of Xuzhou have significantly changed along with the urbanization process. The parameters obtained from GWR imply that the effects of urban expansion on spatial patterns are spatiotemporally varying. CA model helps in better understanding the effects of the considered factors on urban expansion by reproducing historical urban expansion process. The findings provide an effective way to better understand the urbanization process, and to aid the decision making for urban land management. © 2016 Elsevier Ltd


Lin X.,China University of Mining and Technology | Jiang G.,CAS Qingdao Institute of Bioenergy and Bioprocess Technology | Wang Y.,China University of Mining and Technology
Journal of Chemical and Engineering Data | Year: 2017

The advantage of selectivity for coal tar extraction can be obtained by using the solubility parameter of Hansen theory as a guide. However, most of the Hansen solubility parameters (dispersion contributions, δd; polarity contributions, δp; hydrogen bonding contributions, δhb) of coal tar components (e.g., polycyclic aromatic hydrocarbons, PAHs) were inadequate. This study estimated the Hansen solubility parameters of naphthalene, acenaphthene, anthracene, phenanthrene, pyrene, and fluoranthene from coal tar by applying a new approach regulated by turbidimetric titration and a calculating program based on the method of exhaustion. The extended Hansen approach was used to verify the new approach and evaluate the solubility of the six PAH components in different solvents. The results show that the new method can clearly identify the differences in Hansen solubility parameters caused by various combinations of benzene rings among some isomers (e.g., anthracene and phenanthrene). Among the six PAH compounds, high relativity between their Hansen solubility parameters and solubility data was revealed, indicating an excellent reliability of the new method. An extended Hansen approach is appropriate for the estimation of solubility for the six PAHs with acceptable deviations. Moreover, the relationship between the Hansen solubility sphere and the extended Hansen approach was successfully presented by regression analysis. (Graph Presented). © 2017 American Chemical Society.


Yao G.,China University of Mining and Technology | Sun Z.,China University of Mining and Technology | Zheng S.,China University of Mining and Technology
Materials Research Bulletin | Year: 2017

The novel wollastonite/g-C3N4composites were synthesized via a simple calcination and acid leaching process. The as-prepared photocatalysts were characterized by XRD, HRSEM, PL, UV–vis DRS, ESR and BET. The phtotocatalytic performance of the as-synthesizedcomposites was evaluated by the photodegradation of Rhodamine B under visible light irradiation. The visible-light photocatalytic activity of the as-prepared samples is much higher than that of pure g-C3N4. The Di/Wo(H+)-4:3 sample displays the optimal photocatalytic performance towards RhB under visible light and its reaction rate constant is 6.5 times that of pure g-C3N4. Meanwhile, the Di/Wo(H+)-4:3 presents a good durability and reusability. The improved photoactivity of the Di/Wo(H+) composite could be attributed not only to its high surface area and porosity but also to the synergistic effect of the g-C3N4 and wollastonite, which can effectively promote the separation of photogenerated electron-hole pairs and consequently enhanced its photoactivity. © 2016


Dou G.,China University of Mining and Technology | Zhong X.,China University of Mining and Technology
RSC Advances | Year: 2017

The adiabatic oxidation test indicates that the self-heating rate of candle coal (YM) is higher than that of non-coking coal (DFS) in the initial stage, whereas it is lower than that of DFS coal in the later stage. These differences were analyzed based on the 1H NMR spectra of the THF extracts, obtained under ultrasonic irradiation. Some active groups were found in these two coals, and some structural models were designed according to the 1H NMR spectra of the THF extracts. The activation energies (E) and the enthalpy changes (ΔH) of the typical groups were calculated (by Gaussian 09W) to explain the differences in the oxidation characters for the two coals in this study. The results showed that the activation energy (E) for the reaction of (Chemical Equation Presented), of which the YM coal contained more, and ArCH2Ar and (Chemical Equation Presented), of which the DFS coal contained more, was 4.33 kJ mol−1, 37.53 kJ mol−1, and 81.54 kJ mol−1 and the change in the enthalpy values was 48.03 kJ mol−1, 272.76 kJ mol−1, and 78.01 kJ mol−1, respectively, which can explain the differences in the oxidation of these two coals in the low-temperature stage. In conclusion, the differences in the self-heating rate are attributed to the different chemical structures and reactivity of the compounds present in the coals. © The Royal Society of Chemistry.


Lin C.,China University of Mining and Technology | Rao Z.,China University of Mining and Technology
Applied Thermal Engineering | Year: 2017

While paraffin is widely used in thermal energy storage today, its low thermal conductivity has become a bottleneck for the further applications. Here, we construct two kinds of paraffin-based phase change material nanocomposites through introducing boron nitride (BN) nanostructures into n-eicosane to enhance the thermal conductivity. Molecular dynamics (MD) simulation was adopted to estimate their thermal conductivities and related thermal properties. The results indicate that, after adding BN nanostructures, the latent heat of composites is reduced compared with the pure paraffin and they both show a glass-like thermal conductivity which increases as the temperature rises. This happens because the increasing temperature leads to gradually smaller inconsistency in vibrational density of state along three directions and increasingly significant overlaps among them. Furthermore, by decomposing the thermal conductivity, it is found that the major contribution to the overall thermal conductivity comes from BN nanostructures, while the contribution of n-eicosane is insignificant. Though the thermal conductivity from n-eicosane term is small, it has been improved greatly compared with amorphous state of n-eicosane, mainly due to the crystallization effects from BN nanostructures. This work will provide microscopic views and insights into the thermal mechanism of paraffin and offer effective guidances to enhance the thermal conductivity. © 2016 Elsevier Ltd


Yue L.,China University of Mining and Technology
ICALIP 2016 - 2016 International Conference on Audio, Language and Image Processing - Proceedings | Year: 2016

Detecting the mutation information in traveling wave is the key point to realize high voltage direct current (HVDC) transmission line ground fault location, and the fault voltage traveling wave is essentially independent, therefore, the fault location method based on fast independent component analysis (FastICA) algorithm is proposed in this paper. According to the single-ended fault traveling wave location principle, the FastICA is used to isolate fault voltage traveling wave feature signals from multi-channel high voltage direct current transmission line voltage signals, the time of first and second traveling wave head reach the measurement point are recognized, as well as the polarity of the two wave heads are distinguished. The HVDC transmission system model is established in Matlab for simulating a variety of line to ground fault types, the results show that the traveling wave location method based on FastICA can isolate the fault voltage traveling wave feature signals effectively, and the mutation information can be extracted accurately for realizing fault location. © 2016 IEEE.


Zhou A.,China University of Mining and Technology | Wang K.,China University of Mining and Technology
Journal of Loss Prevention in the Process Industries | Year: 2017

To analyze the airflow stabilization induced by gas accumulations in a mine ventilation network, a transient model for airflow caused by gas accumulations is presented. The Runge Kutta method is selected to solve this model. To quantify the average gas density in the transient model, a solution to the gas diffusion equation in airways is interpreted. The Crank-Nicholson difference method is applied to calculate the gas diffusion equation, and the chase method is selected to calculate the gas concentration distribution in airways. Furthermore, a coupled solution between the transient model and the gas diffusion equation is proposed, and a transient airflow ventilation network program for this coupled solution is developed. According to the simulations conducted in this work, it is concluded that the results agree well with the field test. Finally, it was found that gas accumulation in inclined airways can generate gas ventilation pressure, which can lead to airflow disorder. © 2017 Elsevier Ltd


Mo P.-Q.,China University of Mining and Technology | Yu H.-S.,University of Leeds
International Journal of Geomechanics | Year: 2017

The cavity-contraction method has been used for decades for the design of tunneling and prediction of ground settlement by modeling the cavity-unloading process from an in situ stress state. Analytical solutions of undrained cavity contraction in a unified state-parameter model for clay and sand (CASM) are developed in this paper to predict soil behavior around tunnels. The overall behavior of clay and sand under both drained and undrained loading conditions could be properly captured by CASM, and the large-strain and effective-stress analyses of cavity contraction provide the distributions of stress/strain within the elastic, plastic, and critical-state regions around a tunnel. The effects of ground condition and soil model parameters are investigated from the results of stress paths and cavity-contraction curves. Comparisons of the ground-reaction curve and the excess pore pressure are also provided between the predicted and measured behavior of tunneling by using data of centrifuge tunnel tests in clay. © 2016 American Society of Civil Engineers.


Qu J.,China University of Mining and Technology | Zhao J.,China University of Mining and Technology | Rao Z.,China University of Mining and Technology
International Journal of Heat and Mass Transfer | Year: 2017

An experimental investigation on the effect of cooling air velocities, operating orientations and heat inputs on a three-dimensional oscillating heat pipe (3D-OHP) was studied seriously. The 3D-OHP had dimensions of 90 mm × 61 mm × 150 mm, 6 total turns, 3 layers along width direction and 4 layers along length direction. Unlike traditional OHP designs, this new three-dimensional multi-layer design allows for different working conditions in thermal management such as multi-heat source cooling and higher heating fluxes cooling. The thermal performance of the 3D-OHP was studied by testing temperature variation measured at various heat inputs under different cooling air velocities and operating orientations. The results indicated both the cooling air velocities and operating orientation significantly affect the start-up, oscillation and dry-out of the 3D-OHP. The start-up temperature decreased and the dry-out limit increased with the increase of cooling air velocities and the decrease of the operating angle. Difference of thermal resistance in each layer along different directions was also calculated. It was found that only operating orientation had remarkable influence on thermal resistance of different layers along length direction. The difference between the thermal resistance of the skin layer and the inner layer increased with the decrease of operating angle. © 2017 Elsevier Ltd


Feng S.Z.,China University of Mining and Technology | Li A.M.,China University of Mining and Technology
Aerospace Science and Technology | Year: 2017

This study aims to improve the accuracy and efficiency when dealing with thermal and mechanical response in functionally graded cylinder, which is very important in modern aerospace industry. The cell-based smoothed radial point interpolation method (CS-RPIM) is formulated for such analysis. In CS-RPIM, triangular meshes are utilized to discretize problem domains, which can be easily generated. Each triangular element is then partitioned into several smoothing cells. Field functions are constructed by RPIM shape functions and system equations are obtained based on these smoothing cells. Finally, the performances of CS-RPIM are fully investigated through several numerical examples. © 2017 Elsevier Masson SAS


Xu J.,China University of Mining and Technology | Zhai C.,China University of Mining and Technology | Qin L.,China University of Mining and Technology | Yu G.,China University of Mining and Technology
International Journal of Rock Mechanics and Mining Sciences | Year: 2017

Goaf caving is an effective measure to prevent disasters caused by large area roof weighting (LARW). This study uses non-explosive expansion material (NEEM) as a crack source to initiate goaf caving. To evaluate the fracturing capacity of NEEM, we prepared similar specimens with and without an included layer, and different numbers of slots were made along the radial direction of the hole. Acoustic emission and static strain gauge were adopted to monitor energy release and fracture strain damage. All the specimens displayed complex fracture phenomena, and there were positive correlations between fracture number and fractal dimension, fracture density, and the degree of faulting. The fractal dimension and fracture density of layer-bearing specimens were greater than those of specimens without a layer. The released cumulative energy was higher for specimens with two slots than for those with no slots, for specimens both with and without layers. Overall, compared to non-layer specimens, layer-bearing specimens showed a more concentrated energy ratio and a longer duration time of energy release. The relative cumulative energy curves showed several stable rising and abrupt rising patterns, which prolonged the action time of rock internal energy accumulation and accelerated the accumulation of internal damage. © 2017


Shan X.,China University of Mining and Technology | Cheng G.,China University of Mining and Technology
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering | Year: 2017

Explicit dynamical model is the basis of controller design of parallel manipulator. Caused by the close-chain kinematic structure, dynamical model of parallel manipulator is usually complex. To avoid the tedious derivation process of dynamic modeling, explicit dynamical model of a 3SPS+1PS parallel manipulator is established based on Newton-Euler method, and in the dynamical model, joint friction is considered. Based on the kinematics analysis and the force analysis, dynamic model of the 3SPS+1PS parallel manipulator is established. And then, kinematics parameters of the installation sites of the spherical hinges on the moving platform are selected as the intermediate variables, and the intermediate variables are related to the kinematics parameters of the joints. By parameter replacing, the explicit dynamical model of the 3SPS+1PS parallel manipulator with friction of the artificial hip joint, the thrust ball bearing, the spherical hinges and the electric cylinders is obtained. Comparisons between the results from the established model and the results from the actual experiments verify the correctness of the established model. The explicit dynamical model can be applied to controller design and friction compensation control. The methodology can be also used to derive the dynamics of other manipulators. © 2017 Journal of Mechanical Engineering.


Wang X.,China University of Mining and Technology | Kong Y.,China University of Mining and Technology | Gao Y.,Xuzhou Construction Machinery Research Institute | Cheng Y.,China University of Mining and Technology
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing | Year: 2017

To improve the classification accuracy of unlabeled large-scale hyperspectral data, a dimensionality reduction algorithm based on pairwise constraint discriminant analysis and nonnegative sparse divergence (PCDA-NSD) is proposed by using the feature transfer learning technology. Different from labeled sample information that is relatively difficult to acquire, pairwise constraints are a kind of useful supervision information, which can be automatically acquired without artificial interference and thus can better avoid the selection of redundant and noisy samples. Therefore, the pairwise constraint discriminant analysis method is used to learn potential discriminant information of sample sets in the source and target domains. Consequently, positively correlated constraint samples in the source and target domains share one subspace whereas positively and negatively correlated constraint samples are highly separated. Because hyperspectral data in the source and target domains often follow different distributions, a nonnegative sparse divergence is established to measure the divergence between different distributions, based on the nonnegative sparse representation method. Therefore, not only the computation load of the kernel matrix is reduced, but also the natural discriminant capacity is obtained. Experiments of a four-group hyperspectral data show that PCDA-NSD can reduce dimensionality of target data and improve classification accuracy and efficiency by adequate use of the information available in similar hyperspectral data. © 2008-2012 IEEE.


Wang J.,China University of Mining and Technology | Wang Z.,China University of Mining and Technology | Yang S.,China University of Mining and Technology
International Journal of Rock Mechanics and Mining Sciences | Year: 2017

A thorough understanding of the deformation behavior, damage accumulation, and progressive failure of heterogeneous coal is a prerequisite for effective control of the surrounding rock and efficient exploitation of resources in underground coal mines. Such understanding can be obtained by analyzing both the macro- and meso-responses of coal to loading. Accordingly, a coupled macro- and meso-mechanical model for heterogeneous coal is developed and implemented in FLAC3D in the present study. The model is based on elasto-plastic mechanics and the energy dissipation and release principle, and heterogeneity is incorporated by the combination of a statistical approach and the discrete fracture network method. The model is calibrated by experimental data and is used to simulate stress-strain responses, the evolution of acoustic emission (AE) events, and energy conversion in compressed coal. The results reveal that: (1) the model can efficiently capture the dependency of the deformability, compressive strength and AE characteristics on the confining pressure; (2) the anisotropic behavior of heterogeneous coal is realistically realized, and the initiation, propagation and coalescence of micro-cracks can be located and tracked; and (3) stress paths, the degree of heterogeneity, and the unloading rate of confining pressure significantly influence the axial stress-strain response and AE event evolution in the stressed coal. The proposed model produces reasonable values for the roof weighting interval and expansion of the excavation-damaged zone around the gate when compared to the field data measured at the Dongzhouyao mine of China. © 2017 Elsevier Ltd


Xia W.,China University of Mining and Technology | Xie G.,China University of Mining and Technology
International Journal of Mineral Processing | Year: 2017

Coal desulfurization prior to combustion, coking or gasification is beneficial for both the upgrading of quality of commercial coal and the protection of the environment. The sulfur in coking coals usually makes coke unqualified while that in power coals creates several environmental problems, such as acid rain and air pollution. The sulfur forms in coal are primarily divided into two types, i.e. inorganic sulfur and organic sulfur. In most cases, inorganic sulfur is relatively easier to remove than organic sulfur by gravity separation after liberation pretreatments. The primary desulfurization methods include physical, physico-chemical, chemical, and microbial desulfurization. Among the above-mentioned desulfurization methods, chemical-related desulfurization is considered to be the most effective methods for both inorganic and organic sulfur, which is essential to be reviewed. This review highlights the developments in coal chemical-related desulfurization, including acid/alkaline leaching, H2O2 oxidation, electrochemical reduction, solvent extraction, pyrolysis, air oxidation, microwave/ultrasonic assisted desulfurization in the past decade. The effective and future desulfurization technologies are recommended throughout this review. © 2017 Elsevier B.V.


Liu T.,Xuzhou Institute of Technology | Hou J.-H.,Xuzhou Institute of Technology | Peng Y.-L.,China University of Mining and Technology
International Journal of Mineral Processing | Year: 2017

In this study, low-rank lignite coal sample collected from Jining coalfield of Shandong province in China was subjected to desulphurization by using a new bacteria and Acidithiobacillus ferrooxidans isolated from the native coal mine site. The molecular identification of the 16S rRNA gene showed that the new native bacteria was Pseudomonas sp., denoted as NP22, and it is reported for the first time for the capability to remove about 46% of total sulphur from the lignite coal. In the present study, the effects of various parameters such as medium pH, incubation time, pulp density, particle size, incubation temperature on desulphurization from lignite coal with the Pseudomonas sp. NP22 and Acidithiobacillus ferrooxidans were investigated. Analytical characterization indicated that total sulphur content of lignite coal was reduced to 2.76% and 3.23% by using two microorganisms. Also, the calorific value of lignite coal was not affected adversely after two microorganisms’ desulphurization but rather its calorific value increased from 6219 cal/g to 6406 cal/g and 6315 cal/g, however, the ash content of the lignite coal was eliminated. © 2017 Elsevier B.V.


Yu C.,CAS Institute of Geology and Geophysics | Wang Y.,CAS Institute of Geology and Geophysics | Zhao J.,China University of Mining and Technology
Exploration Geophysics | Year: 2017

Seismic diffractions play a vital role in identifying discontinuous geological structures, such as tiny faults and cavities which are important because of their close relationship with the reservoir properties of oil and gas. In this paper, we focus on an extraction method for separation of seismic diffractions. The energy of reflection is usually much stronger than that of the diffraction, thus, removing reflection becomes a key problem for diffraction applications. In order to extract seismic diffractions accurately and stably, we propose an optimised regularisation method based on the local plane-wave equation. By considering two constraints arising from the Sobolev penalty function and the difference operator, we build a stable minimisation model for determining seismic slopes. In computation, an iterative method based on projection onto a convex set for solving the nonlinear minimisation is developed, which can provide fast and accurate solutions. Subtracting the predicted reflections from the seismic image, we can extract the seismic diffractions. Numerical experiments illustrate the effectiveness of the diffraction extraction method in separating tiny faults, scatterers and cavities. Finally, a carbonate reservoir field example is provided to demonstrate the high-resolution capability of the method in revealing small-scale discontinuous geological features. © ASEG 2017.


Han H.,China University of Mining and Technology | Wang J.,China University of Mining and Technology
GPS Solutions | Year: 2017

The combination of new global navigation satellite system (GNSS) has brought great benefits to reliable positioning and ambiguity resolution (AR), especially in restricted environments. However, kinematic positioning over long ranges is still a challenge due to the presence of significant atmospheric uncertainties, which contaminates the AR process. We present a tightly coupled strategy to integrate GNSS and inertial navigation system (INS) by adding ionospheric and tropospheric delay parameters and extending the stepwise AR by applying the partial ambiguity resolution (PAR) strategy. With the aid of INS predictions, the instantaneous AR can be achieved with the proposed atmospheric prediction model, along with a dual-frequency constraint ambiguity validation test. To remove the faults in both dynamic model and measurement model, a robust innovation filtering algorithm is proposed. A field vehicular test was conducted to validate the positioning performance of the proposed algorithm over long ranges. The results show that a reliable positioning solution is obtainable for the global positioning system (GPS)/BeiDou navigation satellite system (BDS)/INS integration system with baseline larger than 130 km. The average number of fixable ambiguities reaches 14.43 by applying PAR. In addition, the fixing ratio of having fixed more than three ambiguities reaches 98.57%. The results also indicate that the robust innovation filtering can efficiently detect the discrepancies in the filter. © 2017 Springer-Verlag Berlin Heidelberg


Shi Z.,China University of Mining and Technology | Shi Z.,Mining Products Safety Approval and Certification Center | Zhu Z.,China University of Mining and Technology
Wear | Year: 2017

The wear characteristics and related mechanisms of the middle plate of a coal conveyor chute were investigated. Multiple sets of wear tests were performed in order to simulate the range in working conditions of the super heavy-load scraper conveyor. Three compositions of mixed material (coal, gangue and water) were tested at different contact pressures and sliding speeds. The results indicate that the wear loss of the middle plate increases with the contact pressure and sliding speed with the same composition mixed material. In addition, the wear loss shows a decreasing trend with an increase in the mass ratio of water, coal and gangue at a specific contact pressure and sliding speed. Based on the substantial analysis of experimental data, interaction technique, modern tribology theory, and the appearance of the samples after the experiment, a statistical wear mechanism distribution diagram of the middle plate was constructed. This diagram is divided into three regions: a slight wear region, a moderate wear region and a severe wear region. The dominant wear mechanism was verified with the observed wear morphology of the middle plate after a given length of time. Therefore, this approach is proposed to be valid and practical. They provide a reliable theoretical basis and technical support for the design, use, and maintenance of the middle plate, the chute, and the entire scraper conveyor. © 2017 Elsevier B.V.


Yu X.,China University of Mining and Technology | Gao J.,China University of Mining and Technology
ISPRS International Journal of Geo-Information | Year: 2017

Multi-constellation global navigation satellite systems (GNSSs) are expected to enhance the capability of precise point positioning (PPP) by improving the positioning accuracy and reducing the convergence time because more satellites will be available. This paper discusses the performance of multi-constellation kinematic PPP based on a multi-constellation kinematic PPP model, Kalman filter and stochastic models. The experimental dataset was collected from the receivers on a vehicle and processed using self-developed software. A comparison of the multi-constellation kinematic PPP and real-time kinematic (RTK) results revealed that the availability, positioning accuracy and convergence performance of the multi-constellation kinematic PPP were all better than those of both global positioning system (GPS)-based PPP and dual-constellation PPP. Multi-constellation kinematic PPP can provide a positioning service with centimetre-level accuracy for dynamic users.


Jiang H.,China University of Mining and Technology
Recent Patents on Mechanical Engineering | Year: 2016

Background: From the view of field application, the working performance and service life of rotary seal device is a determinant factor for successful application of high-pressure water-jet assistance action in coal mining, roadway construction, oil drilling, etc. Objective: To apply the high-pressure water-jet technology in coal-rock mining and drilling equipment, the patent of novel rotary sealing device for high-pressure water is developed for improving its reliability and service life. Methods: The patent of sealing device is installed after the reducer output-shaft of water-jets assisted roadheader, whose aim is to reduce the slip rate of contact surface between O-ring and sealing shaft for extending the service life of sealing material. In addition, the sealing device is developed uses four sealing sleeves, which can improve its reliability and service life. Results: The working performance of rotary sealing device was investigated under different seal ring, water pressure and rotate speed of sealing shaft, and the results show that the static and dynamic sealing performance of Teflon seal ring are all better than that of Chemigum seal ring. With increasing water pressure, the torque of sealing shaft increases slowly when the water pressure is less than 30MPa, but it accelerates when the water pressure exceeds 30MPa. Conclusions: The Teflon O-ring and combined seal ring are better suited for high-pressure water sealing, and the normal working pressure is advised to be less than 30MPa. The leakage volume rate of rotary sealing device increases slowly with rotating speed of sealing shaft according to exponential function, and water pressure changes little when the rotate speed is lower than 70r/min. The patent on dynamic rotary sealing device for high-pressure water can enhance the service life of seal rings about 15 times than that of the present inner spray system. © 2016 Bentham Science Publishers.


Zhang G.,China University of Mining and Technology | Tan Y.,China University of Mining and Technology
Journal of Environmental Chemical Engineering | Year: 2017

Graphical abstract: The BiOCl/TiO2 heterostructure composite has been prepared by sol-gel method. The composite possesses enhanced higher photocatalytic activity for RhB, TC and HCHO degradation than pure TiO2 and BiOCl. The BiOCl/TiO2 heterojunction photocatalysts with varying weight ratio were synthesized through a modified sol-gel method. The prepared photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), N2 adsorption-desorption, X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) and UV-visible diffused reflectance spectroscopy (UV-vis DRS). The photocatalytic activities of the catalysts were evaluated using rhodamine B, tetracycline hydrochloride and formaldehyde as the target pollutants. The characterization results revealed that the BiOCl/TiO2 composite photocatalyst exhibited the higher visible-light-responsive photocatalytic performance than pure BiOCl and TiO2. The results showed that the BiOCl/TiO2 with mass ratio of 70% exhibited the optimal photocatalytic performance. The rate constant of it for rhodamine B degradation is around 11 times as high as that of the pure BiOCl and 46 times than pure TiO2. The enhanced photoactivity should be attributed to the formation of heterojunction between BiOCl and TiO2. The BiOCl/TiO2 hybrid photocatalyst exhibited higher surface area, smaller crystallite size, stronger visible light absorption and improved charge separation efficiency. The excellent activity reveals that BiOCl/TiO2 heterojunction is a promising visible-light-responsive photocatalyst. © 2017 Elsevier Ltd.


Xie J.-L.,China University of Mining and Technology | Xu J.-L.,China University of Mining and Technology
Geosciences Journal | Year: 2017

This study investigates the effect of key stratum on the mining abutment pressure of a coal seam. Firstly, a total of 42 configurations with different key stratum thicknesses and heights have been numerically simulated by the Universal Distinct Element Code (UDEC) software. Then, through the analysis of two sets of parameters derived from the simulation results, the peak abutment pressure and the range of influence, shows that the effect of key stratum on the abutment pressure is conditional. For a relatively small key stratum thickness, less than 159 m, the effect on the abutment pressure is negligible unless the key stratum height is higher than the critical height of 421 m. On the other hand, for the key stratum thickness bigger than 159 m, the abutment pressure is affected irrespective of the key stratum height. Finally, in order to verify the simulation results, the abutment pressure of a field model has been analyzed. The analysis shows that the abutment pressure of the field model with a key stratum is 42% higher than that of the model without any key stratum. The stress at the field model has increased from the virgin stress of 14.6 MPa to the stress of 21.5 MPa. Meanwhile, the stress concentration coefficient has changed from 1 to 1.5, which caused the coal and gas burst disaster. The results of this study can be very useful to explain the reason for the occurrence of some dynamic disasters affected by the key stratum. © 2017 The Association of Korean Geoscience Societies and Springer-Verlag Berlin Heidelberg


Xia W.,China University of Mining and Technology | Niu C.,China University of Mining and Technology | Zhang Z.,Wuhan University of Science and Technology
Powder Technology | Year: 2017

Samples of clean coarse coal particles (0.5–0.25 mm) were used and the flotation process was conducted in the absence of collectors. Scanning electron microscope with energy dispersive spectrometer (SEM/EDS) was used to indicate the elementary composition on coal particle surface as well as particle shape. The attrition process was conducted in a flotation cell with a varied period of stirring process prior to the flotation process. Throughout this paper, it was found that the content of carbon element on coarse coal surface was reduced after attrition whereas the contents of aluminium and silicon elements were increased. A small part of organic matters could release from coarse coal surface by attrition. The attrition process rounded the edges of the coal particles. The flotation performance of coarse coal particles with round corner was worse than that of coal particles with sharp corner. A long period of attrition process could be conducive to obtain a low ash concentrate. © 2017 Elsevier B.V.


Ding N.,China University of Mining and Technology | Zhang S.,China University of Mining and Technology | Zhang Q.,China University of Mining and Technology
Annales Geophysicae | Year: 2017

Water vapor is the basic parameter used to describe atmospheric conditions. It is rarely contained in the atmosphere during the water cycle, but it is the most active element in rapid space-time changes. Measuring and monitoring the distribution and quantity of water vapor is a necessary task. GPS tomography is a powerful means of providing high spatiotemporal resolution of water vapor density. In this paper, a spatial structure model of a humidity field is constructed using voxel nodes, and new parameterizations for acquiring data about water vapor in the troposphere via GPS are proposed based on inverse distance weighted (IDW) interpolation. Unlike the density of water vapor that is constant within a voxel, the density at a certain point is determined by IDW interpolation. This algorithm avoids the use of horizontal constraints to smooth voxels that are not crossed by satellite rays. A prime number decomposition (PND) access order scheme is introduced to minimize correlation between slant wet delay (SWD) observations. Four experimental schemes for GPS tomography are carried out in dry weather from 2 to 8 August 2015 and rainy days from 9 to 15 August 2015. Using 14 days of data from the Hong Kong Satellite Positioning Reference Station Network (SatRef), the results indicate that water vapor density derived from 4-node methods is more robust than that derived from that of 8 nodes or 12 nodes, or that derived from constant refractivity schemes and the new method has better performance under stable weather conditions than unstable weather (e.g., rainy days). The results also indicate that an excessive number of interpolations in each layer reduce accuracy. However, the accuracy of the tomography results is gradually reduced with increases in altitude below 7000 m. Moreover, in the case of altitudes between 7000 m and the upper boundary layer, the accuracy can be improved by a boundary constraint. © Author(s) 2017. CC Attribution 3.0 License.


Kang G.-J.,China University of Mining and Technology | Song C.,China University of Mining and Technology | Ren X.-F.,China University of Mining and Technology
Journal of Photochemistry and Photobiology A: Chemistry | Year: 2017

A series of zinc porphyrin-based dyes (GY21, GY50-GY54) were theoretically investigated using density functional theory and time-dependent density functional theory to examine their performance as sensitizers in dye-sensitized solar cells. The intramolecular charge transfer (ICT) processes of dyes before and after binding (TiO2)9 cluster were fully analyzed by studying the electronic structures, frontier molecular orbitals, electronic transition processes and electron density variations of excited state and ground state. Key parameters associated with the efficiency of dyes were systematically analyzed on the basis of absorption spectra, driving force of electron injection (ΔGinject), and light-harvesting efficiency (LHE). The calculated results confirmed that GY50 had strong ICT character and LHE relative to GY21, which contributed to the high efficiency of GY50. Furthermore, introducing thiophene ring in the π-conjugated linker (GY52-GY54) decreased the HOMO-LUMO energy gaps, enhanced the absorption peaks in near infrared regions as well as the electronic coupling between the dyes and TiO2. This work is expected to provide useful information for designing efficient metal-free organic dyes for improving the performances of dye-sensitized solar cells (DSSCs). © 2016 Elsevier B.V.


Zhao J.,Tsinghua University | Zhao J.,China University of Mining and Technology | Wang D.,China University of Mining and Technology | Yan P.,Tsinghua University
Construction and Building Materials | Year: 2017

To improve the utilization efficiency and application property of smelting solid waste in blended cement, a ternary blended cement (Fuller-SS-S-C binder) containing high volume steel slag (SS) and granulated blast-furnace slag (GBFS or S) was designed and prepared based on Fuller distribution model. The results show that the cumulative distribution of Fuller-SS-S-C binder particles is close to Fuller distribution as a whole, but the particles of 0–15 μm, 15–30 μm, 30–45 μm and 45–80 μm fractions are SS-S-C (composite powder containing SS, S and cement), C (cement), SS-S (composite powder containing SS and S) and SS, respectively. The properties of Fuller-SS-S-C binder can be adjusted by changing compositions of SS-S-C in the range of 0–15 μm. Fuller-SS-S-C binders prepared have higher strength than reference blended cement, and their hydration heat contain three exothermic peaks and concentrate on after 15 hours. Compared with pure cement, the non-evaporable water content of Fuller-SS-S-C binder has great gap, but the pore size distribution of Fuller-SS-S-C binder is dominated by innocuous pores of less than 20 nm, moreover, the porosity, total pore volume and medium pore diameter of Fuller-SS-S-C binder are lower than those of reference blended cement and pure cement, indicating that Fuller-SS-S-C binder has dense microstructure. © 2017 Elsevier Ltd


Tian W.-L.,China University of Mining and Technology | Yang S.-Q.,China University of Mining and Technology
Geomechanics and Engineering | Year: 2017

In this research, experimental and numerical simulations were adopted to investigate the effects of ligament angle on compressive strength and failure mode of rock-like material specimens containing two non-coplanar filled fissures under uniaxial compression. The experimental results show that with the increase of ligament angle, the compressive strength decreases to a nadir at the ligament angle of 60°, before increasing to the maximum at the ligament angle of 120°, while the elastic modulus is not obviously related to the ligament angle. The shear coalescence type easily occurred when α < β, although having the same degree difference between the angle of ligament and fissure. Numerical simulations using PFC2D were performed for flawed specimens under uniaxial compression, and the results are in good consistency with the experimental results. By analyzing the crack evolution process and parallel bond force field of rock-like material specimen containing two non-coplanar filled fissures, we can conclude that the coalescence and propagation of crack are mainly derived from parallel bond force, and the crack initiation and propagation also affect the distribution of parallel bond force. Finally, the displacement vectors in ligament region were used to identify the type of coalescence, and the results coincided with that obtained by analyzing parallel bond force field. These experimental and numerical results are expected to improve the understanding of the mechanism of flawed rock engineering structures. © 2017 Techno-Press, Ltd.


Gui H.,China University of Mining and Technology | Xu J.,China University of Mining and Technology | Zhang D.,China University of Mining and Technology
Environmental Earth Sciences | Year: 2017

Groundwater inrush from karst collapse column (KCC) is a serious water hazard in North China. The factors determining the hydraulic conductivity of KCC remain unclear. This study analyzes the hydraulic conductivity of two KCCs from the same coal mine region and one KCC from different strata and statistically compares lithology-related data for KCCs from 11 coal mines in North China. Finally, we calculated the probability of the hydraulic conductivity of KCC and compared these calculations with field data. The results indicate that the hydraulic conductivity of KCC is mostly affected by surrounding lithology formation and closely correlated with mudstone content. When the thickness ratio of mudstone in the surrounding strata is less than 0.5, the hydraulic conductivity of KCC is more likely to be permeable. This observation of the mudstone thickness ratio provided here can be used as a criterion to qualitatively assess the hydraulic conductivity of KCCs. © 2017, Springer-Verlag Berlin Heidelberg.


The modelling of joint probability distributions of structural system with failure interaction and the reliability-based optimal design of system reliability under incomplete probability information remains a challenge that has not been studied extensively. This article aims to investigate the impacts of copulas for modelling dependence structures between each failure mode of a bevel gear transmission system under incomplete probability information. Firstly, a copula-based reliability method is proposed to evaluate the system reliability of the bevel gear transmission system with established performance functions for different failure modes. The joint probability of failure is estimated with selected copula functions based on the marginal distributions of each failure mode that are approximated by moment-based saddlepoint technology. Secondly, a reliability sensitivity problem is formulated and the formulas for calculating the reliability sensitivity with respect to the distribution parameters of the random variables are presented. Finally, the reliability-based robust optimal design problem is discussed and the optimal model is established. The robustness of the system reliability is ensured by involving the reliability sensitivity into the reliability-based design optimization model. A practical example of the bevel gear transmission system is given to verify the validity of the method. The proposed methods for joint failure probability estimation and robust design optimization are illustrated in the example. The failure probabilities of the system under different copulas can differ considerably. The Gaussian and Clayton copula produce the results that mostly close to the Monte Carlo simulation results. The reliability sensitivity-based robust design is performed based on the Clayton copula-based reliability model. The proposed method is based on the comparative analysis with selected copulas, the results obtained could be supplied as a reference for the optimal design of the gear transmission system. © 2017, Polish Academy of Sciences Branch Lublin. All rights reserved.


Liu W.,China University of Mining and Technology
Sensors (Switzerland) | Year: 2017

The time delay calibration between Light Detection and Ranging (LiDAR) and Inertial Measurement Units (IMUs) is an essential prerequisite for its applications. However, the correspondences between LiDAR and IMU measurements are usually unknown, and thus cannot be computed directly for the time delay calibration. In order to solve the problem of LiDAR-IMU time delay calibration, this paper presents a fusion method based on iterative closest point (ICP) and iterated sigma point Kalman filter (ISPKF), which combines the advantages of ICP and ISPKF. The ICP algorithm can precisely determine the unknown transformation between LiDAR-IMU; and the ISPKF algorithm can optimally estimate the time delay calibration parameters. First of all, the coordinate transformation from the LiDAR frame to the IMU frame is realized. Second, the measurement model and time delay error model of LiDAR and IMU are established. Third, the methodology of the ICP and ISPKF procedure is presented for LiDAR-IMU time delay calibration. Experimental results are presented that validate the proposed method and demonstrate the time delay error can be accurately calibrated. © 2017 by the authors. Licensee MDPI, Basel, Switzerland.


Qin Y.,China University of Mining and Technology | Liu P.,China University of Mining and Technology | Hao Y.,Taiyuan University of Science and Technology
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2017

Considering the three stages of methane flow in coalseam including desorption, migration and seepage, Darcy's law was employed to describe gas migration in coal matrix and fracture, and the gas mass transfer flux between coal matrix and fracture was served as a coupling term to develop a mathematical model of methane flow in a dual-porosity, dual-permeability coal seam and its dimensionless model. The finite difference method was applied to develop a numerical solution for the model. The numerical results show that the decline rate of gas pressure and content in fracture is much faster than that in coal matrix. The gas pressure distribution and gas content in coal matrix are heterogeneous and unsteady over time. A higher permeability of fracture, a higher original gas pressure in coal, or a lower gas pressure outside coal wall, lead to a higher gas emission rate. The dual-porosity and dual-permeability model for methane flow in coal seam is validated to be correct by comparing the simulated results and the field data from Panyi mine. © 2017, Science Press. All right reserved.


Zhao H.,China University of Mining and Technology | Zheng Q.,China University of Mining and Technology | Zhu J.,North China Institute of Science and Technology | Gao X.,Beijing Zhinengxiangying Energy Conservation and Environmental Protection Technology Co.
Modern Tunnelling Technology | Year: 2017

There are so many parameters in theorectical calculation formulas for the limit support force of a shield excavation face, and the calculations are very complex. Based on the popular wedge calculation model, a simplified calculation for the limit support force was studied. The results show that the relationship between the logarithm lnσT of the calculated value and the internal friction angle φ of sandy soil is approximately linear when the internal friction angle is in the range of 20°~70°; and without considering the influence of additional stress on ground, the relation curve of lnσT and φ is approximately parallel under the different factors of sandy soil gravity, the diameter of the shield excavation face and the buried depth. A simplified calculation method for the limit support force of a shield excavation face was obtained by way of linear fitting and introducing the influence coefficients of the sandy soil gravity a, the diameter of the shield tunnel excavation face b and the buried depth c, which simplifies the solving process of the limit support force of a shield excavation face. © 2017, Editorial Office of "Modern Tunnelling Technology". All right reserved.


Li P.,China University of Mining and Technology | Tan Z.,China University of Mining and Technology
Caikuang yu Anquan Gongcheng Xuebao/Journal of Mining and Safety Engineering | Year: 2017

For the accurate state of ground points' displacement and deformation at arbitrary direction caused by underground mining and its principal deformation values, the displacement and deformation state of ground points was analyzed based on probability integration method, and the calculation method was established for principal deformation and its direction of ground points. Based on "strain rosette" method, formulas to calculate arbitrary directions tilt, horizontal movement and its principal direction using two different direction tilt and horizontal movement were derived, also formulas to calculate arbitrary directions curvature, horizontal deformation, distortion and shear and its principal direction using three different direction curvature, horizontal deformation were derived as well. An example of using the formula was described. Another actual ground subsidence prediction was shown to indicate the importance of building impact assessment using the maximum values of ground deformation. The calculation method of "strain rosette" can help work out the surface deformation law clearly and it has practical significance for accurate mining subsidence prediction, building damage assessment and resistance deformation design for buildings over mined goaf. © 2017, Editorial Board of Journal of Mining & Safety Engineering. All right reserved.


Zhang F.,China University of Mining and Technology | Yan X.,China University of Mining and Technology
Chinese Journal of Sensors and Actuators | Year: 2017

To address the problem that the captured videos exist low resolution with noise and long transmission time by using conventional methods of images sampling for mine videos, based on compressed sensing, the algorithm of block compressed sensing for mine videos is proposed. By establishing model of block compressed sensing in mine monitoring videos, the proposed method uses sparse random matrix to sample mine images on sensing nodes. Then, it employs orthogonal matching pursuit (OMP) algorithm to reconstruct image on monitoring center. The results indicate that the proposed method compares favorably with existing schemes at lower reconstruction error, shorter reconstruction time and less sampled data. The Peak Signal-to-Noise Ratio (PSNR) of the algorithm is 8 dB~10 dB higher than that of the method using Scrambled Hadamard matrix, and simultaneously is improved by 1 dB~4 dB in comparison with that of the algorithm which base on wavelet basis, but the time is shortened at least 80%. © 2017, The Editorial Office of Chinese Journal of Sensors and Actuators. All right reserved.


Jiang Y.,China University of Mining and Technology | Jiang Y.,Datong Coal Mine Group Co. | Xie Q.,China University of Mining and Technology
Zhongguo Kuangye Daxue Xuebao/Journal of China University of Mining and Technology | Year: 2017

A series of activated carbons were prepared by briquetting method from Datong bituminous coal and Shenli lignite blending in the presence of Fe3O4, and their adsorption performance, magnetic properties and pore structure were characterized. Besides, the primary process parameters and coal blending ratio were optimized by means of orthogonal experiment in which caramel decoloration rate was used as an index of water clarifying performance. The results show that the introduction of Shenli lignite to Datong bituminous coal in the case of Fe3O4-free has negative effects on pore development of activated carbon; higher temperature can effectively enhance the burning loss of pore wall by activating agent which results in the enlargement of porosity; the catalytic effect of Fe3O4 accelerates growth of mesopores and/or macropores, improves the caramel decoloration rate of activated carbon and gives it magnetic property. Finally, two sets of optimized process parameters were obtained with 6% Fe3O4 addition in feedstock, which are (1) 100% Datong coal with activation temperature of 980℃ and activation time of 3 h, and (2) Blending of Datong coal and Shenli lignite with mass ratio of 80:20, activation temperature of 980℃, activation time of 3.5 h, by which magnetic-separable high quality activated carbon for water treatment with caramel decoloration rate of 79% and 76% can be prepared respectively. © 2017, Editorial Board of Journal of CUMT. All right reserved.


Zhang T.,China University of Mining and Technology | Wang R.,China University of Mining and Technology | Zhu D.,China University of Mining and Technology
Zhongguo Kuangye Daxue Xuebao/Journal of China University of Mining and Technology | Year: 2017

This paper aims to study the mineral composition of shale reservoirs affecting gas storage, seepage flow migration and exploitation results. With XRD, SEM, low temperature liquid nitrogen and reservoir sensitivity experiment system, we analyzed the mineral compositions characteristics of three sets of marine shales from the northeast of Jiangxi province and their significance, so as to find the mineralogical compositions of organic-rich shales in the Paleozoic erathem of the lower Yangtze region. The three sets of marine shales are Upper Sinian Series Piyuangcun formation (Z2p), Lower Cambrian Series Hetang formation (∈1h), Upper Permian Series Leping formation (P3l). The three sets of shale samples all have an overwhelmingly dominant content of illites in the clay mineral and low content of kaolinites, which indicates that they have experienced the late diagenesis period. The sedimentary environment is mainly deep shelf sedimentary environment controlled by alkaline aqueous medium. The relatively reducing environment provides a favorable deposition condition for the formation and evolution of shale gas reservoirs. The three sets of marine shale are characterized by the high brittleness index and prone to be transformed and fractured. Compared with North America and upper Yangtze region in China, the study area is an ideal target for shale gas exploration and development. The results show that the mineral compositions of the three sets of shales are mainly dominated by quartz (with mass fraction of 46.73%-64.81%), followed by clay minerals, and minerals such as calcite, dolomite, siderite and pyrite. The clay mineral compositions of the three sets of organic-rich shales are all characterized by their highest mass fraction of illite (74.58%-87.00%), followed by illite/smectite interstratified mineral (6.44%-20.58%). The brittleness index mean value of Piyuancun formation, Hetang formation and Leping formation are 67.35, 77.90 and 48.95 respectively, suggesting that these formations are easy to be fractured. The quartz in the mineral compositions mainly affect the development of macro-pores, which is beneficial for seepage flow and migration of shale gas. Whereas, clay minerals control the development of micro-pores and is negatively correlated to porosity and permeability, which is beneficial for the storage of shale gas but not for seepage flow. The sensitivity of Piyuancun formation and Hetang formation shale reservoir is not obvious. Leping formation has medium to weak velocity sensitivity, medium to strong water sensitivity and medium to weak acid sensitivity effect. The ideal sequence for the key exploration and development stratum of shale gas from better to worse can be set as Hetang formation, Piyuancun formation, Leping formation. The shale gas development technology should be treated separately according to the mineral compositions changes in different regions. © 2017, Editorial Board of Journal of CUMT. All right reserved.


Jia C.-L.,China University of Mining and Technology | Li S.,China University of Mining and Technology | Song X.-X.,China University of Mining and Technology
Applied Physics A: Materials Science and Processing | Year: 2017

Yb:NaGd(WO4)2 single crystals are implanted with 6.0 MeV O ions at room temperature. The effects of ion irradiation on the structure and spectral properties are demonstrated by employing X-ray diffraction techniques, high resolution X-ray diffraction techniques and photoluminescence (PL) measurement. The corresponding results show that the sample can retain good crystallinity by irradiation at relative low fluences of 1.6 × 1014 ions/cm2, whilst both the PL intensity and the line bandwidth can be effectively improved. © 2017, Springer-Verlag Berlin Heidelberg.


Li W.-P.,China University of Mining and Technology | Wang Q.-Q.,China University of Mining and Technology | Li X.-Q.,China University of Mining and Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2017

In the arid-semiarid area of northwest China, the shallow water such as the water of rivers and lakes, valley runoff water, the phreatic water of Quaternary in sand-layer and so on are precious water resources which maintain regional ecological geological environment and the body of water resource protection in coal mining. According to the regional geological structure of the shallow water aquifer-aquifuge, the N2 laterite, distributed widely above coal seam in northwest coal field of China, as the direct aquifuge bottom of regional shallow water or valleys runoff cushion, playing a crucial role to the coal mining with water protection and ecological environment protection, is the key aquifuge soil. In this paper, based on the analysis of regional distribution features, the basic physical, hydro-physical and the mechanical properties of N2 laterite, the impermeability of post-mining stress recovery creep, before mining crack and post mining was deeply studied and analyzed by the water pressure test before and after mining, the test of creep permeability and the experiment of soil-water interaction and so on. The results show that the N2 laterite has a good capacity of self-recovery after the impermeability was broken by mining crack. The mechanism of impermeability self-recovery was explained from the perspective of geological structure, soil-water interaction and rheological properties; and according to this finding, the reconstruction of aquifuge and major engineering geological properties included was proposed. © 2017, Editorial Office of Journal of China Coal Society. All right reserved.


Pu H.,China University of Mining and Technology | Ni H.-Y.,China University of Mining and Technology | Xiao C.,China University of Mining and Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2017

Theoretical analysis is taken on the water sediment two phase flows pattern of fractured rock based on lattice Boltzmann method and a model is built. Also, the basic conservation equations are derived and the control equations are established. The water and sand phase interface is analyzed by using the Euler point and Lagrange point based on the immersed boundary method. Numerical simulation is taken on sand inrush, and the flow patterns of sand moving in fracture is analyzed, the influence of particle size and fracture width on the velocity of sand inrush is studied. With the results in single fracture, a mechanical model of sand mining roof covered with thick loose is established to analyze water and sand inrush, the authors find that at the initial stage, the sand particles flowing in cracks can restrain its development, with the water pressure continually applied, a large number of water and sand mixture begin to flow in, which makes the pore pressure increase, causing the cracks rapidly develop, even causing the roof fall, aggravating the water and sand inrush. © 2017, Editorial Office of Journal of China Coal Society. All right reserved.


Yue Z.-W.,China University of Mining and Technology | Wang X.,China University of Mining and Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2016

A digital dynamic caustic experimental system was used to study the effect of different notched orientations to the blast-induced main crack propagation behavior. Five different notched orientations were studied on how they influence blast-induced crack propagation and interaction. The result proves that the difference of included angle has obvious effect on the blast-induced main crack propagation trajectory. The larger the included angle of notches orientations, the larger the crack propagation velocity in the medium term of blast-induced main crack propagation. When the included angle of notched orientations are 90°, 135°and 180°, the second peak values in the blast-induced main crack tip will appear. © 2016, Editorial Office of Journal of China Coal Society. All right reserved.


Wu Y.-X.,China University of Mining and Technology | Tian Y.-M.,China University of Mining and Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2016

Currently the methods of coal-rock recognition have achieved some stage results,but this still cannot meet the production demands.In order to develop a new method of coal-rock recognition,the technique of coal-rock image feature extraction and recognition based on dictionary learning was researched.The dictionary learning algorithm is proposed to apply for extracting the feature of coal-rock image.The method of random selection is adopted to initialize and update the dictionary.The classification algorithm is adopted to identify the coal-rock image.The results show that the feature extraction method by dictionary learning can simply and effectively express the characteristic information of coal-rock image,and achieve a high recognition rate.Research results could provide a new method for the coal-rock interface automatic recognition. © 2016, Editorial Office of Journal of China Coal Society. All right reserved.


Lin Z.-Z.,China University of Mining and Technology | Huang C.-L.,China University of Mining and Technology | Zhen W.-K.,China University of Mining and Technology | Huang Z.,China University of Mining and Technology
Applied Thermal Engineering | Year: 2017

In this paper, for the first time, the sintering treatment is applied to enhance the thermal conductivity and the mechanical property of the copper and the nickel nanoparticle packed beds (NPBs) which could realize low-temperature joining and high-temperature service as a soldering material used in the electronic device. Following the sintering treatment of NPBs, the hot-wire method and the Vickers hardness tester are applied to measure the thermal conductivity and the hardness of NPBs respectively. The sintering temperature and the tableting pressure both influence the thermal conductivity of NPBs greatly and the sintering temperature has a lager advantages than the tableting pressure in enhancing the thermal conductivity. With a sintering temperature larger than 800 K, the thermal conductivity can be enlarged even 2.45-folds than that without sintering treatment, because of the decreased porosity and the importantly improved nanoparticle contact conditions. On the other hand, with a large tableting pressure which will lead to a small porosity and a large nanoparticle coordination number, the thermal conductivity is only increased more than 0.41 times. Meanwhile, with the increase of the sintering temperature, the hardness of NPBs follows the same increase trend as that of the thermal conductivity. This study provides a simple and effective way in increasing the thermal conductivity and the hardness of NPBs simultaneously for a soldering application. © 2017


Lv C.,China University of Mining and Technology | Wu Z.,China University of Mining and Technology | Wu Z.,China Academy of Safety Science and Technology
Applied Thermal Engineering | Year: 2017

Through establishing a non-adiabatic open-ended steel pipe with a length of 20 m and a cross-sectional area of 0.08 m × 0.08 m, the changing rules of flame propagation and flame thickness of premixed methane/air explosion with a 10% fuel concentration and a 20% filling ratio were revealed. The experimental results show that the flame arrival time increased gradually with the increase of the distance from the ignition source, the maximum flame signal value initially increased along the pipe but then dropped. The flame thickness at a certain point could be measured by the time differences between vanishing moment and initial rising moment of flame signal at this point. With the increase of the distance from the ignition source, the flame thickness gradually decreased, the flame propagation speed presented a changing trend of increasing and decreasing, while the maximum overpressure followed a trend of decreasing, increasing and decreasing. The research results provide the scientific experimental basis for the reasonable setting mine explosion-resistant device, it is of great significance to effectively restrain the spread of explosion flame surface and avoid accident enlarging of gas explosion in coal mine. © 2017 Elsevier Ltd


Luo Q.,China University of Mining and Technology | Wang G.,China University of Mining and Technology
RISTI - Revista Iberica de Sistemas e Tecnologias de Informacao | Year: 2016

With the development and advancement of information technique, the form of data varies and the amount of the multimedia database increases. Video data mining is a very important part of the multimedia data mining, and it is also the new research aspect of data mining. Meanwhile, with easier acquisition and storage of the video data, the problem of how to utilize them effectively becomes increasingly serious. For instance, the security detection applied in video surveillance and emergencies, video content-based extraction of objects in a ball game. Video data mining is different form general database mining. Because of the complexity of video data structure, big size and high redundancy cause slow technology development in video mining. Thus, research and study on improving video retrieval and indexing speed have become the focus of data mining discussion. In this paper, we analyzed the system structure of video data mining, and summarized the concept of video mining. At the same time, we put forward several efficient video data mining algorithms after discussing the recent video mining technology.


Liu D.,China University of Mining and Technology | Zhu S.,China University of Mining and Technology | Chang W.,China University of Mining and Technology
International Journal of Systems Science | Year: 2017

In this paper, mean square exponential input-to-state stability (exp-ISS) of stochastic memristive complex-valued neural networks (SMCVNNs) is investigated. By utilising Lyapunov functional and stochastic analysis theory, a sufficient criterion is derived to assure the mean square exp-ISS of the SMCVNNs. The obtained results not only generalise the previous works in the literature about real-valued neural networks as special cases, but also can be easily checked by parameters of system. Numerical simulations are given to show the effectiveness of our theoretical results. © 2017 Informa UK Limited, trading as Taylor & Francis Group


Xie Z.,China University of Mining and Technology
Journal of Geometry and Physics | Year: 2017

Wintgen ideal submanifolds in space forms are those ones attaining equality pointwise in the so-called DDVV inequality which relates the scalar curvature, the mean curvature and the normal scalar curvature. In this paper, we investigate three special classes of Wintgen ideal submanifolds: the ones with constant mean curvature, the ones with constant scalar curvature and the ones with constant normal scalar curvature. Some characterization results are given. © 2017 Elsevier B.V.


Hu Y.,China University of Mining and Technology | Racke R.,University of Konstanz
Journal of Mathematical Fluid Mechanics | Year: 2017

We investigate the compressible Navier–Stokes equations where the constitutive law for the stress tensor given by Maxwell’s law is revised to a system of relaxation equations for two parts of the tensor. The global well-posedness is proved as well as the compatibility with the classical compressible Navier–Stokes system in the sense that, for vanishing relaxation parameters, the solutions to the Maxwell system are shown to converge to solutions of the classical system. © 2016, Springer International Publishing.


Mao L.,State University of New York at Stony Brook | Mao L.,China University of Mining and Technology | Chiang F.-P.,State University of New York at Stony Brook
Acta Mechanica | Year: 2016

Speckle photography technique is a versatile displacement/deformation mapping technique that can be applied to almost any material. It has its genesis in the laser speckle interferometry technique whereby the natural speckles created by illuminating an optically rough surface using a coherent laser beam are used as displacement gauging elements. It evolves into the white light speckle photography technique whereby a random pattern of any type is used as a displacement measurement transducer. With the advent of digital cameras and ubiquitous usage of computers, the digital version of the technique is developed. Up to now, the technique is essentially limited to 2D applications. Recently, we extended the technique into the 3D domain by using the volumetric imaging capabilities of CT or MRI. In this paper, we apply this technique to measuring the internal deformation of rocks. It so happens that certain rocks have natural density variation at various places such that when imaged by CT these impurities can be treated as 3D speckles. The elements of volumetric speckle photography technique are as follows. A reference volumetric image of the rock is recorded by a micro-CT scan and stored as a reference. Under load, the deformed CT image of the rock is also recorded. Both volume images are divided into subsets of certain voxel arrays. Each corresponding pair of the subsets is “compared” via a two-step 3D Fourier transform analysis. The result is a 3D map of displacement vectors representing the collective displacement experienced by all the speckles within the subset of voxels. The strain distribution of the entire rock specimen can then be calculated using appropriate displacement strain relations. The application of this technique to strain mapping of red sandstone and argillite rocks is presented. © 2015, Springer-Verlag Wien.


Yin S.-P.,China University of Mining and Technology | Peng C.,China University of Mining and Technology | Jin Z.-Y.,China University of Mining and Technology
Journal of Composites for Construction | Year: 2017

Textile-reinforced concrete (TRC) is currently being used as an effective inorganic reinforcement material due to its high bearing capacity, anticracking capacity, and corrosion resistance. However, the compressive performance of TRC-strengthened concrete columns under chloride corrosion is unclear. Therefore, this paper first studied mechanical properties of RC columns strengthened with TRC with a variable number of textile layers and overlap lengths in a conventional environment. Then, compressive performances of RC columns strengthened with TRC under chloride wet-dry cycling and coupling effects of chloride wet-dry cycling and sustained axial compressive load were studied. The experimental results indicated that the TRC's constraint ability could make better use of the compressive performance of concrete and improve the failure mode of the compression column. The bearing capacity and ductility of RC columns was improved with an increasing number of textile layers; the increase in the lap length of the textile had only a slight impact on bearing capacities of columns, which slightly improved the ductility of the TRC-strengthened RC columns. The bonding properties of the interface between the TRC and concrete decreased slightly due to the corrosion effect of chloride ions. Thus, the ultimate bearing capacity and deformation capacity of RC columns strengthened with TRC declined after chloride wet-dry cycling; the coupling effects of chloride wet-dry cycles and the sustained axial compressive load negatively affected the bearing capacity and ductility of TRC-strengthened RC columns. The ultimate load and ductility of strengthened columns decreased with the increase in the sustained load. © 2016 American Society of Civil Engineers.


Liu K.,China University of Mining and Technology | Gong D.-W.,China University of Mining and Technology
Kongzhi yu Juece/Control and Decision | Year: 2017

A multi-objective optimization model for the problem of gesture segmentation is proposed, and a method of solving the above model based on evolutionary algorithms is presented. When building the model, the positions of a series of pixels are taken as the decision variable, and the differences between the color of the pixels and that of a hand are taken as the objective functions. In addition, a multi-objective estimation of the distribution algorithm is presented based on the correlation among the positions of the hand pixels to solve the model so as to get the best pixel set, thus forming the human gesture. The experimental results show the effectiveness of the proposed model and algorithm. © 2017, Editorial Office of Control and Decision. All right reserved.


Fu G.,China University of Mining and Technology | Cao J.,China University of Mining and Technology | Wang X.,China University of Mining and Technology
Energy Procedia | Year: 2017

In order to identify the causal factors of 88 coal and gas outburst accidents and their relationships, this paper proposed a cause classification framework based on the accident causation "2-4" model (24Model). The correlations between the high level and low level causes were analyzed by the Chi-square test for independence. Results showed that root causes, indirect causes and unsafe acts were prevalent in all cases. The main direct causes were violation operation and violation action; the main indirect causes were lack of safety knowledge and low safety awareness; the main radical cause was safety management procedures; the main root causes was safety depending on safety awareness. And there were ten groups of causes with significant correlation between the high level and low level causes. The work paths of different causes in coal and gas outburst accidents were identified by using the proposed cause classification framework. © 2017 The Authors.


Li J.-Q.,Shenzhen University | Rong Z.-H.,Beihang University | Chen X.,China University of Mining and Technology | Yan G.-Y.,CAS Academy of Mathematics and Systems Science | You Z.-H.,CAS Xinjiang Technical Institute of Physics and Chemistry
Oncotarget | Year: 2017

Nowadays, researchers have realized that microRNAs (miRNAs) are playing a significant role in many important biological processes and they are closely connected with various complex human diseases. However, since there are too many possible miRNA-disease associations to analyze, it remains difficult to predict the potential miRNAs related to human diseases without a systematic and effective method. In this study, we developed a Matrix Completion for MiRNA-Disease Association prediction model (MCMDA) based on the known miRNA-disease associations in HMDD database. MCMDA model utilized the matrix completion algorithm to update the adjacency matrix of known miRNA-disease associations and furthermore predict the potential associations. To evaluate the performance of MCMDA, we performed leave-oneout cross validation (LOOCV) and 5-fold cross validation to compare MCMDA with three previous classical computational models (RLSMDA, HDMP, and WBSMDA). As a result, MCMDA achieved AUCs of 0.8749 in global LOOCV, 0.7718 in local LOOCV and average AUC of 0.8767+/-0.0011 in 5-fold cross validation. Moreover, the prediction results associated with colon neoplasms, kidney neoplasms, lymphoma and prostate neoplasms were verified. As a consequence, 84%, 86%, 78% and 90% of the top 50 potential miRNAs for these four diseases were respectively confirmed by recent experimental discoveries. Therefore, MCMDA model is superior to the previous models in that it improves the prediction performance although it only depends on the known miRNA-disease associations.


Zhu R.,University of Kiel | Liserre M.,University of Kiel | Chen Z.,University of Aalborg | Wu X.,China University of Mining and Technology
IEEE Transactions on Industrial Electronics | Year: 2017

A zero-sequence circulating current (ZSCC) is typically generated among the multiparallel converters that share the common dc link and ac side without isolated transformers under the space vector modulation (SVM), due to the injected third-order zero-sequence voltage (ZSV). This paper analyzes SVM techniques, studies the effects of the ZSV on the ZSCC control loop in detail, and then proposes an improved SVM scheme to suppress the impact of the ZSV on the ZSCC. The proposed strategy can effectively realize the ZSCC suppression, even though the parallel converter modules have asymmetrical current references and filter inductances. The simulation and experimental results based on the parallel converters clearly verify the effectiveness of the proposed control. © 2016 IEEE.


Liu Z.,China University of Mining and Technology | Qiu L.,China University of Mining and Technology | Pan F.,China University of Mining and Technology
Quantum Information Processing | Year: 2017

We consider the enhancement effect of quantum partially collapsing measurements, i.e., weak measurement and quantum measurement reversal, on quantum coherence and quantum Fisher information, both of which are transmitted through a spin-chain channel. For the state parameter lying in the region (π/2,π), weak measurement can enhance quantum coherence and quantum Fisher information. For the state parameter lying in the region (0,π/2), quantum coherence and quantum Fisher information can be enhanced by quantum measurement reversal combined with weak measurement. We assume the probabilistic nature of the method should be responsible for the enhancement. © 2017, Springer Science+Business Media New York.


Zheng C.,China University of Mining and Technology | Geng F.,China University of Mining and Technology | Rao Z.,China University of Mining and Technology
Computational Materials Science | Year: 2017

Fuel cell polymer membranes such as the Dow, Nafion and Aciplex membranes as the core of the proton exchange membrane fuel cell (PEMFC) play an important role in maintaining high intrinsic proton conductivity. For investigating the dynamic properties and thermal properties of fuel cell polymer membranes, the proton mobility and thermal conductivities of the Dow, Nafion and Aciplex membranes were calculated by using molecular dynamics (MD) simulations. Compared with the Dow and the Nafion membranes, the Aciplex membrane presented a better mobility of water molecules and hydronium ions at 350 K and it showed a better thermal property due to its side chain is long enough to form a “highway” of heat conduction. The results indicated that both the structure of side chain and temperature have effect on the dynamic properties and thermal properties of fuel cell polymer membranes. © 2017 Elsevier B.V.


Wei Y.,Guilin University of Electronic Technology | Pasalic E.,University of Primorska | Zhang F.,China University of Mining and Technology | Hodzic S.,University of Primorska
Information Sciences | Year: 2017

Although several methods for estimating the resistance of a random Boolean function against (fast) algebraic attacks were proposed, these methods are usually infeasible in practice for relatively large number of input variables n (for instance n ≥ 30) due to increased computational complexity. An efficient estimation of the resistance of Boolean functions, with relatively large number of inputs n, against (fast) algebraic attacks appears to be a rather difficult task. In this paper, the concept of partial linear relations decomposition is introduced, which decomposes any given nonlinear Boolean function into many linear (affine) subfunctions by using the disjoint sets of input variables. Based on this result, a general probabilistic decomposition algorithm for nonlinear Boolean functions is presented which gives a new framework for estimating the resistance of Boolean function against (fast) algebraic attacks. It is shown that our new probabilistic method gives very tight estimates (lower and upper bound) and it only requires about O(n22n) operations for a random Boolean function with n variables, thus having much less time complexity than previously known algorithms. © 2017 Elsevier Inc.


Wang Q.,China University of Mining and Technology | Chen H.,China University of Mining and Technology | Zhao R.,China University of Mining and Technology
IET Electric Power Applications | Year: 2017

In this study, a novel double-loop control strategy is proposed to improve performance of switched reluctance generator (SRG) systems. The proposed double-loop control contains a power loop to control output power and an efficiency loop to optimise system efficiency. Development of the double-loop control contains three parts. First, a modified angle-voltage control (MAVC) scheme is developed to control phase current over the entire operating range. Second, firing parameters are optimised to enlarge the output power range when the SRG is controlled by MAVC. The turn-off angle is calculated by a simplified model; the turn-on angle and the DC-link voltage are optimised by differential evaluation algorithm. Third, an online mechanical power estimator is designed, with which the input mechanical power can be estimated for online efficiency optimisation in the efficiency loop. In the end, simulation and experimental results are presented to validate resulting improvements of the proposed control strategy. © The Institution of Engineering and Technology 2016.


Shang D.,China University of Mining and Technology
International Journal of Rotating Machinery | Year: 2017

The efficiency of a drainage pump should be tested at regular intervals to master the status of the drainage pump in real time and thus achieve the goal of saving energy. The ultrasonic flowmeter method is traditionally used to measure the flow of the pump. But there are some defects in this kind of method of underground coal mine. This paper first introduces the principle of testing the main drainage pump efficiency in coal mine using thermodynamic theories, then analyzes the energy transformation during the process of draining water, and finally derives the calculation formulae of the pump efficiency, which meet the on-site precision of engineering. On the basis of analyzing the theories, the protective sleeve and the base of the temperature sensor are designed to measure the water temperature at inlet and outlet of the pump. The efficiencies of pumps with two specifications are measured, respectively, by using the thermodynamic method and ultrasonic flowmeter method. By contrast, the results show that thermodynamic method can satisfy the precision of the testing requirements accuracy for high-flow and high-lift drainage pump under normal temperatures. Moreover, some measures are summed up to improve the accuracy of testing the pump efficiency, which are of guiding significance for on-site testing of the main drainage pump efficiency in coal mine. © 2017 Deyong Shang.


Liu K.,YanKuang Group Information Center | Zhang M.,China University of Mining and Technology
Proceedings - 2016 9th International Symposium on Computational Intelligence and Design, ISCID 2016 | Year: 2017

In recent years, with the extensive application of the path planning technology, the development prospect of this technology is more and more broad, and the scientific research value of it is also more and more important. It is very necessary to apply it to the underground coal mine with complex terrain, and the algorithm is the core content of the research on path planning. We add simulated annealing algorithm into the process of ant colony algorithm formed simulated annealing ant colony algorithm in this paper, and apply it to the path planning, solve the local optimum problem caused by precocity in ant colony algorithm. For further ensure to find the optimal path, entropy increase strategy was used, that means using multiple update path to avoid algorithm premature, it's easier to find global optimal solution. Simulation result shows that the method presented in this paper obtains the optimization path and proves that the algorithm is efficient and reliable. © 2016 IEEE.


Shibo W.,China University of Mining and Technology | Niu C.,China University of Mining and Technology | Teng B.,China University of Mining and Technology
Journal of Tribology | Year: 2017

Wear characteristics were influenced by the parameters of wear-testing apparatus including configuration of contact surface and form of the relative motion. The tribological behavior of polytetrafluoroethylene (PTFE) disk against AISI1045 steel pin under unidirectionally rotating, linearly reciprocating, and torsional motion was studied. The friction coefficients under unidirectional rotating, linearly reciprocating and torsional motion were 0.1, 0.118 and 0.12, respectively. The highest wear mass loss of PTFE was obtained under linearly reciprocating. The wear mass loss under torsional motion was lowest. The wear mechanism of PTFE under unidirectional rotating, linearly reciprocating, and torsional motion was slight plowing, serious abrasive wear, and adhesive wear, respectively. Through finite element analysis, a higher normal stress induced by the edge effect of steel pin promoted a higher shear stress in PTFE disk. The plastic ratcheting mechanism occurred on the contact edge when the steel pin entered and exited the contact zone, as led to higher wear mass loss under linearly reciprocating and unidirectional rotation. The plastic ratcheting mechanism did not occur under torsional motion. Different transfer films with various topographies were formed on the steel pins under the three motions. © 2017 by ASME.


Niu C.,China University of Mining and Technology | Shibo W.,China University of Mining and Technology
Journal of Tribology | Year: 2017

A statistical model for torsional friction of plate-on-plate contact is constructed. The torsional responses including T- curves, proportion of slip asperities, and the radius of gross slip can be obtained from the model. The torsional friction response of monomer cast (MC) nylon against 316L stainless steel was calculated with this model and a torsional friction experiment of MC nylon against 316L stainless steel was performed to verify the model. The calculated T-curves exhibit different shapes under different torsional angular displacements. The calculations demonstrated that the torsional regime determined only through T-curves was inaccurate. The statistical results of asperities located at the torsional interface more directly reflected the torsional regime. The T-curves obtained from theoretical calculation and experiments are consistent in shapes, whereas the torque magnitude from the theoretical calculation is larger than that from experiments. When gross slip is indicated by the maximum torque on the T-curves, about 93% of the contact asperities were in a slip status rather than 100% and the gross slip radius in the whole torsional contact interface was about 3 mm. © 2016 by ASME .


Fan J.,China University of Mining and Technology | Feng R.,Southern Illinois University Carbondale | Wang J.,Chongqing Institute of Geology and Mineral Resources | Wang Y.,China University of Mining and Technology
Rock Mechanics and Rock Engineering | Year: 2017

Geological sequestration of CO2 in coal seams is of significant interest to both academia and industry. A thorough laboratory investigation of mechanical and flow behaviors is crucial for understanding the complex response of coalbeds to CO2 injection-enhanced coalbed methane recovery (CO2-ECBM) operation. In this work, systematic experiments were carried out on cylindrical coal core specimens under different uniform confining stresses. The coal deformation caused by variations in effective stress as well as the sorption-induced matrix swelling/shrinkage was monitored. The competitive gas sorption characteristics and permeability evolution during the process of methane displacement by CO2 were also investigated. The measured volumetric strain results indicate that sorption-induced strain is the dominant factor in the coal deformation. The relationship between the volumetric strain and the adsorbed gas volume has been revealed to be a linear function. Experimental results obtained under different stress conditions suggest that higher confining stress suppresses the increase in both volumetric strain and the adsorbed gas volume. Furthermore, both methane displacement and CO2 injection are reduced when applying higher confining stresses. In addition, the permeability enhancement is heavily suppressed at higher confining stress. At a certain confining stress, a characteristic “U-shaped” trend of permeability is presented as a function of decreasing pore pressure. This study contributes to the understanding of coal deformation and its impact on permeability evolution under uniformly stressed condition, which has practical significance for CO2 sequestration and CO2-ECBM operation in the Qinshui basin. © 2017 Springer-Verlag Wien


Wu G.,China University of Mining and Technology | Feng T.-T.,East China Normal University | Zhang L.-J.,Jiangsu University | Yang M.,Soochow University of China
Pattern Recognition | Year: 2017

Exponential discriminant analysis (EDA) is a generalized discriminant analysis method based on matrix exponential. It can essentially overcome the intrinsic difficulty of small-sample-size problem that exists in the classical linear discriminant analysis (LDA). However, for data with high dimensionality, one has to solve a large matrix exponential eigenproblem in this method, and the time complexity is dominated by the computation of exponential of large matrices. In this paper, we propose two inexact Krylov subspace algorithms for solving the large matrix exponential eigenproblem efficiently. The contribution of this work is threefold. First, we consider how to compute matrix exponential-vector products efficiently, which is the key step in the Krylov subspace method. Second, we compare the discriminant analysis criterion of EDA and that of LDA from a theoretical point of view. Third, we establish the relationship between the accuracy of the approximate eigenvectors and the distance to nearest neighbor classifier, and show why the matrix exponential eigenproblem can be solved approximately in practice. Numerical experiments on some real-world databases show the superiority of our new algorithms over their original counterpart for face recognition. © 2017 Elsevier Ltd.


Fan L.,China University of Mining and Technology | Fan L.,Pennsylvania State University | Liu S.,Pennsylvania State University
International Journal of Coal Geology | Year: 2017

This paper proposed a conceptual model of broken rock mass compaction based on elastic theory by simplifying the compression process. This conceptual model assumes that the contact connection between two adjacent rock particles is similar to a cubic mass. With this simplification, the stress-strain constitutive law is established. The change in the secant modulus in the mechanical model derived from the variation of the connection coefficient agrees well with the reported experimental results. The permeability of compacted rock mass evolution was modeled based on the cubic law. The mechanical compression model was coupled with the permeability evolution model. The modeled permeability evolution is consistent with reported simulation and experimental results. The modeled permeability results were validated using Karacan's data with broken shale rock properties. Compared to an intact rock mass, we found that the stress-strain curve of a compacted rock mass takes a longer compression path to reach linearity due to the void space compaction resulting from friction slipping and the re-arrangement of particles. It was also found that the particle elastic modulus does not contribute to the overall bulk compaction and permeability reduction at the initial compaction stage. However, the particle elastic modulus controls the permeability evolution for a fully compacted gob, where the gob can be treated as an intact rock mass. The proposed conceptual models will potentially lay the foundation for future permeability and caving behavior characterizations using numerical simulations for complex gob areas. © 2017 Elsevier B.V.


Tian F.,China University of Mining and Technology | Wong D.,China University of Mining and Technology
Discrete Applied Mathematics | Year: 2017

Let Gσ be an oriented graph with skew adjacency matrix S(Gσ). The skew energy ES(Gσ) of Gσ is the sum of the norms of all eigenvalues of S(Gσ) and the skew rank sr(Gσ) of Gσ is the rank of S(Gσ). In this paper, it is proved that ES(Gσ)≥2μ(G) for an arbitrary connected oriented graph Gσ of order n, where μ(G) is the matching number of G, and the equality holds if and only if G is a complete bipartite graph Kn2,n2 with partition (X,Y) of equal size and σ is switching-equivalent to the elementary orientation of G which assigns all edges the same direction from vertices of X to vertices of Y. As an application, we prove that ES(Gσ)≥sr(Gσ) for an oriented graph Gσ and the equality holds if and only if G is the disjoint union of some copies of K2 and some isolated vertices. © 2017 Elsevier B.V.


Wang X.,China University of Mining and Technology | Wang Y.,China University of Mining and Technology
Wuhan Daxue Xuebao (Xinxi Kexue Ban)/Geomatics and Information Science of Wuhan University | Year: 2017

Based on the analyses of unit functions and unit function types of the interior space, an interior-space network-topology model that contained semantic information, supported path analysis, and fully expressed the topological logic of the various parts of the interior space was constructed after considering the demand for three-dimensional (3D) high-quality space navigation rendering, and limitations in personal mobile platform resources and computing power. In addition, by accurately determining the regions and topological logic of the interior space, strategies for space division and organization and strategy adjustment of geometric models based on topological relations of the interior space were explored, achieving the goal of dynamic interruption and elimination of interior models. The applicability, feasibility, and effectiveness of the proposed model were verified by performing actual tests using personal mobile platforms. The results indicated that the methods proposed in this study could interrupt and eliminate geometric models in real time, significantly reducing the number of models rendered and enhancing data transmission and rendering efficiency. This method provided reliable data and assurance concerning the visualization and rendering of high-fidelity 3D models. © 2017, Research and Development Office of Wuhan University. All right reserved.


Zou D.,Jiangsu University | Li S.,RMIT University | Li Z.,China University of Mining and Technology | Kong X.,Jiangsu University
Energy Conversion and Management | Year: 2017

A new global particle swarm optimization (NGPSO) algorithm is proposed to solve the economic emission dispatch (EED) problems in this paper. NGPSO is different from the traditional particle swarm optimization (PSO) algorithm in two aspects. First, NGPSO uses a new position updating equation which relies on the global best particle to guide the searching activities of all particles. Second, it uses the randomization based on the uniform distribution to slightly disturb the flight trajectories of particles during the late evolutionary process. The two steps enable NGPSO to effectively execute a number of global searches, and thus they increase the chance of exploring promising solution space, and reduce the probabilities of getting trapped into local optima for all particles. On the other hand, the two objective functions of EED are normalized separately according to all candidate solutions, and then they are incorporated into one single objective function. The transformation steps are very helpful in eliminating the difference caused by the different dimensions of the two functions, and thus they strike a balance between the fuel cost and emission. In addition, a simple and common penalty function method is employed to facilitate the satisfactions of EED's constraints. Based on these improvements in PSO, objective functions and constraints handling, high-quality solutions can be obtained for EED problems. Five examples are chosen to testify the performance of three improved PSOs on solving EED problems with or without transmission losses. Experimental results show that NGPSO is the most efficient approach on solving the single objective optimization (fuel cost or emission minimization) and multi-objective optimization (fuel cost and emission minimizations) problems. © 2017 Elsevier Ltd


Tian Z.-J.,China University of Mining and Technology | Jiang B.-F.,China University of Mining and Technology
Guangzi Xuebao/Acta Photonica Sinica | Year: 2017

A structure of two-dimensional incident left-handed metamaterial composed of double trapezoid metal strips was proposed based on paralleled metal strips and thin metal wire. The structure consists of dielectric-slab and anti-symmetrical trapezoid metal strips on each side. Compared with the traditional left-handed metamaterial structures, this structure not only has double left-handed frequency band under the parallel incidence of electromagnetic wave, but also has a good expansibility, and it is easy to produce. By using the simulation software, the structure is analyzed respectively when electromagnetic waves are incident perpendicularly and when they are parallel to the substrate. Results show that, the structure can show double negative properties either under the incidence of electromagnetic waves paralleled or perpendicular. Besides, with the upper base size of the structure being greater for each 0.5 mm, the frequency band of double negative properties moves to higher frequency band about 0.2 GHz and 0.4 GHz.These can be as reference values in the research of left-handed metamaterial based on paralleled meta strips. © 2017, Science Press. All right reserved.


Yang X.-J.,China University of Mining and Technology | Gao F.,China University of Mining and Technology
Thermal Science | Year: 2017

In this paper, a new technology combing the variational iterative method and an integral transform similar to Sumudu transform is proposed for the first time for solutions of diffusion and heat equations. The method is accurate and efficient in development of approximate solutions for the partial differential equations. © 2017 Society of Thermal Engineers of Serbia.


Lu C.-C.,China University of Mining and Technology | Bai L.,China University of Mining and Technology
Wuli Xuebao/Acta Physica Sinica | Year: 2017

The heat transfer process inevitably occurs in the operation of real heat engine. In this article, a low-dissipation heat engine with generic heat transfer process is proposed based on the low-dissipation Carnot model. The formulas for the power and the efficiency of heat engine with generic heat transfer law are derived, and the low-dissipation heat engine performance is also optimized by the trade-off optimization method, which offers a unified scheme to understand the behaviors of heat engines with generic heat transfer processes. Furthermore, the characteristics of the power as well as the efficiencies for thermal engines with the different heat transfer processes are discussed in detail, and it is found that the power and the efficiency without heat transfer process are independent of heat leak, but are related to contact time, heat dissipation and Carnot efficiency. The power output of heat engine monotonically increases as Carnot efficiency increases, but the large contact time ratio and the large dissipation ratio make it difficult to provide the big power output. When the heat leak is absent and α (β) is fixed, the efficiency of heat engine decreases (increases) with the increase of β (α). It is noted that the heat transfer process greatly influences the performance of heat engine, and ηΩ/ηC versus β displays the similar properties under three heat transfer laws. It is clearly shown that ηΩ/ηC versus β shows the transition from the monotonic decrease to monotonic increase with α increasing, but ηΩ/ηC versus α is opposite to the former, and the maximum value of ηΩ/ηC also shifts rightwards with the increase of β. Additionally, the corresponding efficiency of heat engine diminishes significantly as m decreases and n increases. When heat engines are dominated by different heat transfer laws, the curves of ηΩ versus ηC are consistent as ηC is relatively large or small, but it is observed that there exist the evident differences among three characteristic curves in the middle regime. The relatively large β or small α will also lead to the reduction of the working regime where heat engine can function normally. Our results are very helpful in understanding the design principle and the optimization mechanism for actual thermal engines and refrigerators. © 2017 Chinese Physical Society.


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.


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.


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.


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.


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.


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.


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.


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.


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.


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.


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.


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.


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.


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.


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.


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 engineerin