Taiyuan, China

Taiyuan University of Technology is a university in Shanxi, People's Republic of China, under the authority of the provincial government. In 2012 it celebrated its 110th anniversary. It is listed officially as one of the 'Top 100 universities in China', according to the Chinese government. Wikipedia.


Time filter

Source Type

Zhang K.,Taiyuan University of Technology | Cao Q.,Taiyuan University of Technology | Jin L.,Taiyuan University of Technology | Li P.,Taiyuan University of Technology | Zhang X.,Taiyuan University of Technology
Journal of Hazardous Materials | Year: 2017

Coal–oil–water slurry (COWS) synfuel can be prepared successfully by waste engine oil (WEO), water and coal in the existence of Tween 80 and SL. The effects of coal type, coal particle size distribution, and WEO blending proportion (α) on the slurryability of COWS were investigated, and certain essential properties, such as slurryability, rheology, thixotropy, and stability of COWS were examined. The results show that the maximum coal content of COWS decreases with an increment in α, ranging from 60 wt.% at α = 0 to 48 wt.% at α = 15 wt.%. The apparent viscosity of COWS becomes high when the amount of WEO is increased for the same coal content. The lower heating value (19.15 kJ/g) of 48 wt.% COWS (α = 15 wt.%) is equivalent to that of CWS with 67.88 wt.% coal. The mass ratio of separated supernatant to oil–water emulsion for COWS with 49 wt.% coal decreases by 1.12% while the amount of WEO is increased to 15 wt.% from 10 wt.%. COWS exhibits the non-Newtonian pseudoplastic fluid behavior. Its pseudoplasticity and thixotropy are also promoted as the coal content of COWS is increased. And the dispersion and stabilization mechanism of COWS is discussed. © 2017 Elsevier B.V.


Hou J.,Taiyuan University of Technology | Chai J.,Taiyuan University of Technology
International Journal of Theoretical Physics | Year: 2017

We introduce a class of states so-called semi-SSPPT (semi super strong positive partial transposition) states in infinite-dimensional bipartite systems by the Cholesky decomposition in terms of operator matrices and show that every semi-SSPPT state is separable. This gives a method of constructing separable states and generalizes the corresponding results in Chruściński et al. (Phys. Rev. A 77, 022113 2008) and Guo and Hou (J. Phys. A: Math. Theor. 45, 505303 2012). This criterion is specially convenient to be applied when one of the subsystem is a qubit system. © 2017 Springer Science+Business Media New York


Hou J.,Taiyuan University of Technology | Hou J.,Henan Polytechnic University | Zhang J.,Henan Polytechnic University
International Journal of Hydrogen Energy | Year: 2017

The robustness of the efficient syngas (ES, H2 +CO) fraction in an entrained flow coal gasification is very important to the stable operations of some downstream applications. This study presents the details about the robust optimization of the ES fraction in a typical entrained flow coal gasification, Shell coal gasification process (SCGP). In this study, Taguchi method combined with response surface methodology (RSM) was used. A series of numerical experiments in Aspen plus were carried out according to the operations of a demonstration SCGP gasifier. After systematic statistical analysis, the ES fraction was robust optimized using Nelder-Mead algorithm. The results show that integrating Taguchi and RSM method provides an effective solution to the robust optimization of the ES fraction. Oxygen to coal ratio (O/C) is the "robust factor" which significantly affects not only the ES fraction but also the fluctuation in it. The ES fraction increases at first and decreases later with increasing O/C, but the fluctuation in it is just the opposite. Pressure (P) is the "regulation factor" which has no effects on the ES fraction but can change the fluctuation. Thus adjusting it to a moderate level is helpful for further suppressing the fluctuation. Stream to coal ratio (S/C) is the "secondary factor" which has slightly effect on the ES fraction and the fluctuation. The optimal robust solutions of the control parameters, P, S/C and O/C, are 3.69 MPa, 0.05 and 0.61 kg/kg respectively. Under this condition, the fraction of ES is about 98.42% with 0.18% fluctuation, which presents good robustness. © 2017 Hydrogen Energy Publications LLC.


Wang H.,Taiyuan University of Technology | Wang B.,Taiyuan University of Technology | Wen Y.,Taiyuan University of Technology | Huang W.,Taiyuan University of Technology
Catalysis Letters | Year: 2017

Abstract: Potassium phosphate supported on ion-exchanged CsX zeolite was prepared by impregnation method, and their performance was investigated for the side-chain alkylation of toluene with methanol. When K3PO4 was more than 5 wt%, the catalyst activity and selectivity of styrene and ethylbenzene were improved significantly. The conversion of methanol and selectivity of styrene and ethylbenzene reached 84.1 and 92.8% with K3PO4 loading of 7 wt%. It was concluded that moderate addition of K3PO4 decreased the amount of weak acid and increased the strength and amount of middle base sites. The base sites at 270–300 °C (CO2-TPD) were favorable for this reaction. Graphical Abstract: [Figure not available: see fulltext.] © 2016, Springer Science+Business Media New York.


Duan Y.,Taiyuan University of Technology | Li W.R.,Taiyuan University of Technology | Zhao Y.,Taiyuan University of Technology
IOP Conference Series: Earth and Environmental Science | Year: 2017

The "methanation + anaerobic ammonia oxidation autotrophic denitrification" method was adopted by using anaerobic sequencing batch reactors (ASBRs) and realized a satisfactory synchronous removal of chemical oxygen demand (COD) and ammonia-nitrogen (NH4 +-N) in wastewater after 75 days operation. 90% of COD was removed at a COD load of 1.2 kg/(m3•d) and 90% of TN was removed at a TN load of 0.14 kg/(m3•d). The anammox reaction ratio was estimated to be 1: 1.32: 0.26. The results showed that synchronous rapid start-up of the methanation and anaerobic ammonia oxidation processes in two-stage ASBRs was feasible. © Published under licence by IOP Publishing Ltd.


Wang L.,Nanyang Technological University | Chan F.F.,Nanyang Technological University | Wang Y.,Taiyuan University of Technology | Chang Q.,Taiyuan University of Technology
IEEE Region 10 Annual International Conference, Proceedings/TENCON | Year: 2017

This study uses delayed neural network models to predict public housing prices in Singapore. The delayed neural networks are used to estimate the trend of the resale price index (RPI) of Singapore housing from the Singapore Housing Development Board (HDB), with nine independent economic and demographic variables. The results show that the delayed neural network model is able to produce a good fit and predictions. © 2016 IEEE.


Gao B.,Taiyuan University of Technology
Waves in Random and Complex Media | Year: 2017

This paper focus on two aspects. Firstly, symmetry analysis is performed for the Boussinesq–Whitham–Broer–Kaup equation which can degenerate to the Boussinesq equation, the Whitham–Broer–Kaup equation and the Broer–Kaup equation. As a byproduct, the similarity reductions and exact solutions of the equation are constructed based on the optimal systems. Secondly, the explicit solutions are considered by the power series method. Moreover, the convergence of the power series solutions are shown. The physical significance of the solutions is considered from the transformation group point of view. © 2017 Informa UK Limited, trading as Taylor & Francis Group


Jing L.,Southwest Jiaotong University | Jing L.,Xi'an Jiaotong University | Yang F.,Guangdong University of Technology | Zhao L.,Taiyuan University of Technology
Composite Structures | Year: 2017

The perforation resistance capability of clamped square sandwich panels with layered gradient metallic foam cores subjected to the hemispherical-nosed projectile impact was investigated numerically. The previous penetration tests on monolithic foam core sandwich panels were used to validate the present simulation approach, and then the deformation process, critical velocity and energy absorption of monolithic Al plate, ungraded and layered-gradient sandwich targets were studied, respectively. Influences of the strain rate and asymmetric face-sheets on the perforation resistance of the layered-gradient sandwich target were also discussed. The simulation results indicate that layered-gradient sandwich targets have the worst perforation resistance and energy absorption capability, and then the ungraded sandwich panel, and the monolithic plate is the best. For layered-gradient sandwich panels, the perforation resistance is hard to improve obviously by changing the arrangements of core-layers. Besides, the strain rate effect of materials and asymmetric face-sheets contribute to enhance the perforation resistance of layered-gradient sandwich targets only for the low-velocity penetration condition. These findings are beneficial for guiding the design and assessment of layered-gradient sandwich structures in engineering applications. © 2017 Elsevier Ltd


SHEN L.-X.,Taiyuan University of Technology | HUANG Y.-K.,Taiyuan University of Technology | LI T.,Taiyuan University of Technology
Journal of Integrative Agriculture | Year: 2017

Maize genotypes vary significantly in their nitrogen use efficiencies (NUEs). Better understanding of early grain filling characteristics of maize is important, especially for maize with different NUEs. The objectives of this research were (i) to investigate the difference in apical kernel development of maize with different NUEs, (ii) to determine the reaction of apical kernel development to N application levels, and (iii) to evaluate the relationship between apical kernel development and grain yield (GY) for different genotypes of maize. Three maize hybrid varieties with different NUEs were cultivated in a field with different levels of N fertilizer arranged during two growing seasons. Kernel fresh weight (KFW), volume (KV) and dry weight (KDW) of apical kernel were evaluated at an early grain filling stage. Ear characteristics, GY and its components were determined at maturity stage. Apical kernel of the high N and high efficiency (HN-HE) type (under low N, the yield is lower, and under higher N, the yield is higher) developed better under high N (N210 and N240, pure N of 210 and 240 kg ha−1) than at low N (N120 and N140, pure N of 120 and 140 kg ha−1). The low N and high efficiency (LN-HE) type (under low N, the yield is higher, while under higher N, the yield is not significantly higher) developed better under low N than at high N. The double high efficiency (D-HE) type (for both low and high N, the yield is higher) performed well under both high and low N. Apical kernel reacted differently to the N supply. Apical kernel developed well at an early grain filling stage and resulted in a higher kernel number (KN), kernel weight (KW) and GY with better ear characteristics at maturity. © 2017 Chinese Academy of Agricultural Sciences


Liu X.,Taiyuan University of Technology | Liu S.,Taiyuan University of Technology | Fan M.,Taiyuan University of Technology | Zhang L.,Taiyuan University of Technology
Fuel | Year: 2017

The interactions in the “lignite-surfactant” system were studied with the aim of disclosing the mechanism of the decrease in hydrophilicity of lignite using cetyltrimethylammonium bromide (CTAB). The inhibiting efficiency in the hydrophilicity of lignite by CTAB was studied by measuring the wetting heat using a Calvet calorimeter. The adsorption of CTAB to organic content and mineral matter was analyzed, and the relationship between the distribution characteristics of different functional groups and the inhibiting efficiency in hydrophilicity was discussed. The hydrophilicity of lignite was decreased significantly after adsorption of CTAB. CTAB decreased the hydrophilicity more effectively for a more strongly hydrophilic sorbate, and an excess adsorption was not beneficial. Competitive adsorption existed between the oxygen-containing groups and the silicon-containing mineral matter of lignite, and the adsorption to oxygen-containing groups occurred prior to reaching the mineral matter surface. The decrease in hydrophilicity of lignite by CTAB was shown to be closely associated with the distribution characteristics of the adsorbed layer. Coverage of the oxygen-containing groups by a directed surfactant layer was mainly devoted to the decrease in the wetting heat of lignite. Among these oxygen-containing groups, the COO/COOH group of lignite played a key role in the decrease of hydrophilicity due to its high adsorption capacity for CTAB. © 2017 Elsevier Ltd


Ma J.,Taiyuan University of Technology | Ren W.,Taiyuan University of Technology | Zhao J.,Taiyuan University of Technology | Yang H.,Taiyuan University of Technology
Journal of Alloys and Compounds | Year: 2017

Directly growth of TiO2 nanoflowers on fluorine drop tin oxide (FTO) glass substrates were achieved by a one-step hydrothermal process. These TiO2 nanoflowers films are preeminent with strong adhesion, low internal resistance and large dye loading. They are beneficial for improving the photoelectric properties of DSSCs (dye sensitized solar cells). In the process of preparing TiO2 nanoflowers films, gradually increasing the dosage of tetrabutyl titanate, compact and uniform Rutile TiO2 nanoflowers layer can be achieved, the coverage of TiO2 nanoflowers increased along with it. Employ these TiO2 nanoflowers as the photoanode in DSSCs, the optimal DSSCs performed with a short-circuit current density of 5.77 mA cm−2, an open-circuit voltage of 0.65 V, fill factor of 48.66 and an energy conversion efficiency of 1.83% because of large dye loading and high light harvesting ability of the DSSCs with appropriate tetrabutyl titanate and reaction temperature. Excessive or insufficient tetrabutyl titanate, or lower reaction temperature will endanger the performance of DSSCs. © 2016 Elsevier B.V.


Liu L.,Taiyuan University of Technology | Hou Z.,Taiyuan University of Technology
Materials Letters | Year: 2017

A novel process combining brush alignment and two-step sintering was explored to prepare grain-oriented KSr2Nb5O15 (KSN) ceramics. Needle-like KSN particles in slurry were aligned by the brush force along c-axis, which were synthesized by molten salt method. The sintered ceramics show an enhanced density of 96% and well-oriented structure. The Lotgering factor of green compact was 0.21 and increased to 0.95 for (00l), as calculated from X-ray diffraction. These results suggested that this process was a potential way for the preparation of dense grain-oriented ceramic materials. © 2016 Elsevier B.V.


Wu M.,Taiyuan University of Technology | Shi L.,Taiyuan University of Technology | Mi J.,Taiyuan University of Technology
Journal of Thermal Analysis and Calorimetry | Year: 2017

Microporous activated carbons were prepared from the semi-coke of coal liquefaction residual by KOH activation. The gas evolution during the activation process was analyzed by thermogravimetry–mass spectrometry. The SO2 adsorption equilibrium and desulfurization kinetics at low temperatures were also investigated. The results of this study indicate that three reactions are mainly responsible for the formation of pore structure in the activated carbons. The physical adsorption dominates the adsorption of SO2 (250–1250 ppm SO2, N2 as balance gas) at lower temperature for activated carbons. The Boltzmann model was found to be suitable for describing the desulfurization behavior of selected activated carbon at low temperatures under non-oxygen atmosphere instead of the linear driving force model. The apparent sorption rate constant of activated carbon ranges from 0.0027 to 0.0038 s−1. The temperature-programmed desorption study of the adsorption-saturated (393 K, 5% O2 + 1250 ppm SO2 + N2 balance) activated carbon suggests the presence of two types of adsorbed SO2 with the bond energy of 45.17 and 52.00 kJ mol−1, respectively. © 2017 Akadémiai Kiadó, Budapest, Hungary


Sun P.,Shandong University | Lu F.,Shandong University | Wu A.,Shandong University | Shi L.,Taiyuan University of Technology | Zheng L.,Shandong University
Soft Matter | Year: 2017

Wormlike micelles were successfully fabricated by the self-assembly of a single-tailed zwitterionic surface-active ionic liquid (SAIL), 3-(1-hexadecyl-3-imidazolio) propanesulfonate β-naphthalene sulfonate (C16IPS-Nsa), in aqueous solutions without any additives. With increasing zwitterionic SAIL concentration, spontaneous transition from micelles to wormlike micelles and then a hexagonal phase occurs. Interestingly, the wormlike micelles are closed, stretched and directionally arranged, which was rarely found in previous research studies. This kind of wormlike micelle is useful to serve as novel soft template in the synthesis of functional materials.1H NMR illustrated that the introduced π-π stacking and hydrophobic interactions originated from the hydrophobic aromatic counterions are responsible for the structural transformation. Density functional theory (DFT) simulated the optimum configuration of C16IPS-Nsa and calculated the interaction energy of C16IPS-Nsa-H2O is 39.6 kJ mol-1. This work paves the way for regulating the self-assembly structures of amphiphiles through changing specific weak interactions. © The Royal Society of Chemistry.


Song J.,Taiyuan University of Technology | Song S.,Taiyuan University of Technology | Qu B.,Taiyuan University of Technology
2016 IEEE 2nd Annual Southern Power Electronics Conference, SPEC 2016 | Year: 2016

Nonlinear inductance profiles of switched reluctance motor (SRM) cause the complicated design of controllers, which leads to SRMs have not been widely applied in industries fileds. A traditional PI controller with fixed gain is easy to realize the control of SRMs. It can not provide good control performance over the whole range of speed regulation. To solve the problem, an adaptive PI controller of speed regulation, easy to achieve, is designed based on the characteristics of SRM in this paper. A first-order dynamic model in s domain is derived according to the simplified model of SRM. The relationship between PI parameters, average voltage and actual speed of the system is obtained based on the first-order dynamic model and then the adaptive adjustment of PI parameters is realized. The characteristics between traditional PI controller and adaptive PI controller have been compared by experiments, and results show that a better performance is achieved by adopting the adaptive PI controller. The system has rapid response with little overshoot, zero steady state error and high robustness to load torque disturbance. © 2016 IEEE.


Dong X.,Taiyuan University of Technology | Tian Q.,Taiyuan University of Technology | Li Z.,Taiyuan University of Technology
Energy and Buildings | Year: 2017

The solar integrated air source heat pump (SIASHP) with R407c for radiant floor heating without water (RFHW) is proposed and investigated. The first generation of prototype of SIASHP RFHW system developed is suitable for marketization at the present. On the basis of experiment room in Taiyuan, the energy and exergy analysis of SIASHP RFHW system are implemented, compared with the same type of conventional air source heat pump (ASHP). On the condition of −9.9 °C outdoor calculated dry-bulb temperature for space heating in winter, Taiyuan and a 130 W/m2 solar irradiance, the 76.8% exergy efficiency of SIASHP is 7.9% higher than the 71.1% exergy efficiency of ASHP. The 2.55 COP of SIASHP is 5.8% higher than the 2.41 COP of ASHP. From 9:00 to 21:00, the 2.89 kWh power consumption of SIASHP is 7.4% lower than the 3.12 kWh of ASHP. The 52.7% process quality number of SIASHP is higher than the 51.4% of ASHP. The SIASHP RFHW system with no water pipe exposed to outdoor environment is safe and convenient for the narrow and vertical outdoor installation space of high-rise building users to meet their individual demand of space heating. © 2017 Elsevier B.V.


Jia T.-T.,Taiyuan University of Technology | Chai Y.-Z.,Taiyuan University of Technology | Hao H.-Q.,Taiyuan University of Technology
Superlattices and Microstructures | Year: 2017

Under investigation in this paper is the generalized coupled nonlinear Hirota (GCH) equations with addition effects by the Hirota method, which is better than the coupled nonlinear Schrödinger equations in eliciting optical solitons for increasing the bit rates. The bilinear form has been constructed, via which multi-solitons and breathers are derived. In particular, the three-bright soliton solution and breathers are derived and simulated via some pictures. The propagation characters are analyzed with the changes of the key parameters. © 2017 Elsevier Ltd


Tang Y.,State Key Laboratory of Deep Coal Mining and Environment Protection | Tang Y.,Taiyuan University of Technology
World of Mining - Surface and Underground | Year: 2017

Coal and gas outbursts, as a kind of disasters generally found in highly gassy mines around the world, have significantly influenced safe, efficient production of mines. By using sodium humate as the cementing agent to prepare the briquettes, this study physically simulated the process of coal and gas outburst using a self-made equipment. In addition, orthogonal experiments were carried out to analyze the main factors influencing outbursts. Results showed that no outbursts occurred before the gas pressure reached 0.75 MPa. When the gas pressure and crustal stress were equal to 1.0 MPa and 20 MPa, separately, coal and gas outbursts occured with an intensity being 26.7 kg·m and farthest distance of 14.1 m. Moreover, it was found that the energy in the outburst process continuously attenuated. Acoording to the orthogonal test, gas pressure is the primary factor controlling coal and gas outburst process. When the water content in coal grew to 4 %, the outburst intensity rapidly reduced, indicating that increasing the content of water in coal is conducive to controlling outburst disasters.


Gao Y.,Taiyuan University of Technology | Meng F.,Taiyuan University of Technology | Cheng Y.,Taiyuan University of Technology | Li Z.,Taiyuan University of Technology
Applied Catalysis A: General | Year: 2017

Urea–nitrates solution combustion system was facile modified by adding various fuel additives, and used for synthesizing nanosized Ni–Al2O3 catalysts. Among the three kind of fuel additives, i.e., ammonium acetate, starch and polyethylene glycol (PEG), the addition of ammonium acetate into urea–nitrates system results in numerous ignition points and uniform propagation of flames in gas–phase, which is conducive to the formation of small and dispersive NiO particles. Moreover, thermal analysis reveals that ammonium acetate, benefiting from its simultaneous decomposition with urea and metal nitrates as well as endothermic characteristic, serves as an inhibitor in combustion system that adsorbs the combustion heat to prevent the agglomeration of NiO particles. As a result, the optimum Ni–Al2O3 catalyst retains an desirable CO conversion of 92% and CH4 selectivity of 86% toward methane synthesis via slurry phase CO methanation at 260 °C, 1.0 MPa and 6000 mL/gcat·h within 50 h. Taking ammonium acetate as a fuel additive, a solution combustion synthetic fashion is expected to optimize the nanostructure and activity of Ni–Al2O3 catalyst. © 2017 Elsevier B.V.


Sun R.,Chinese Academy of Sciences | Jia P.,Taiyuan University of Technology
Publications of the Astronomical Society of the Pacific | Year: 2017

Space debris is a special kind of fast-moving, near-Earth objects, and it is also considered to be an interesting topic in time-domain astronomy. Optical survey is the main technique for observing space debris, which contributes much to the studies of space environment. However, due to the motion of registered objects, image degradation is critical in optical space debris observations, as it affects the efficiency of data reduction and lowers the precision of astrometry. Therefore, the image restoration in the form of deconvolution can be applied to improve the data quality and reduction accuracy. To promote the image processing and optimize the reduction, the image degradation across the field of view is modeled statistically with principal component analysis and the efficient mean point-spread function (PSF) is derived from raw images, which is further used in the image restoration. To test the efficiency and reliability, trial observations were made for both low-Earth orbital and high-Earth orbital objects. The positions of all targets were measured using our novel approach and compared with the reference positions. The performance of image restoration employing our estimated PSF was compared with several competitive approaches. The proposed image restoration outperformed the others so that the influence of image degradation was distinctly reduced, which resulted in a higher signal-to-noise ratio and more precise astrometric measurements. © 2017. The Astronomical Society of the Pacific. All rights reserved.


Wang W.,Nanjing Southeast University | Wang W.,Zhejiang University | Chen H.,Nanjing Southeast University | Li X.,Taiyuan University of Technology | Zhu Z.,Nanjing Southeast University
Construction and Building Materials | Year: 2017

To study the corrosion behavior of steel bars in alkali-activated slag (AAS) system, simulated pore solutions of AAS mortar were first applied in this work. The effects of the three major species in AAS pore solutions, namely sulfur-containing species, aluminate, and silicate, were investigated. Electrochemical impedance spectroscopy and potentiodynamic polarization results showed that the simulated pore solution of AAS mortar had a stronger capacity to passivate and protect steel bars than the simulated pore solution of Portland cement (PC) mortar, mainly due to the higher concentration of silicate in the former, as confirmed by surface analysis of SEM-EDXS. © 2017


Ren T.,Taiyuan University of Technology | Li Y.,Taiyuan University of Technology
Engineering Letters | Year: 2017

Pilot placement allocation is a key factor to improve the channel estimation performance in orthogonal frequency division multiplexing (OFDM) systems. However, conventional pilot optimization scheme is not attractive due to its high computational complexity under exhaustive search. To address this problem, a novel joint pilot design scheme utilizing the stochastic optimization scheme is proposed in this paper. It is focused on pilot placement optimization to improve the performance of sparse channel estimation. The proposed scheme combines the coherence minimization criterion and effective feedback of channel state information (CSI) at the receiver to jointly optimize the pilot placement to obtain the near-optimal pilot pattern, it is a trade off between accurate channel estimation and computational complexity without affecting the systems bandwidth usage. Simulation results show that the proposed scheme achieves better bit error rate (BER) performance when compared with the known stochastic optimization algorithm and random method. © 2017, International Association of Engineers. All rights reserved.


Zhang L.-L.,Taiyuan University of Technology | Zhang L.-L.,Beijing Institute of Technology | Wang X.-M.,Taiyuan University of Technology
Superlattices and Microstructures | Year: 2017

Studied in this paper is a general two-coupled nonlinear Schrödinger system, in which the coefficients of the self-phase modulation, cross-phase modulation and four-wave mixing terms are arbitrary. With the Hirota method, the bilinear form and periodic one- and two-soliton solutions are derived. Propagation characteristics of periodic solitons are mainly discussed. Under certain conditions, not only general mixed-type vector soliton solutions can be gotten from our results such as bright-dark, dark-bright and bright-bright solitons, but also some new mixed-type vector soliton solutions are generated, including bright-periodic, periodic-bright, dark-periodic and periodic-dark solitons. Dynamic behaviors of those solitons are discussed through graphic simulation. © 2017 Elsevier Ltd


Xin Y.,Taiyuan University of Science and Technology | Xu G.,Taiyuan University of Science and Technology | Su N.,Taiyuan University of Technology
Shock and Vibration | Year: 2017

The operators of overhead traveling cranes experience discomfort as a result of the vibrations of crane structures. These vibrations are produced by defects in the rails on which the cranes move. To improve the comfort of operators, a nine-degree-of-freedom (nine-DOF) mathematical model of a "human-crane-rail" system was constructed. Based on the theoretical guidance provided in ISO 2631-1, an annoyance rate model was established, and quantization results were determined. A dynamic optimization design method for overhead traveling cranes is proposed. A particle swarm optimization (PSO) algorithm was used to optimize the crane structural design, with the structure parameters as the basic variables, the annoyance rate model as the objective function, and the acceleration amplitude and displacement amplitude of the crane as the constraint conditions. The proposed model and method were used to optimize the design of a double-girder 100 t-28.5 m casting crane, and the optimal parameters are obtained. The results show that optimization decreases the human annoyance rate from 28.3% to 9.8% and the root mean square of the weighted acceleration of human vibration from 0.59 m/s2 to 0.38 m/s2. These results demonstrate the effectiveness and practical applicability of the models and method proposed in this paper. © 2017 Yunsheng Xin et al.


Yan D.,Taiyuan University of Technology | Zhao J.,Taiyuan University of Technology | Niu S.,Taiyuan University of Technology
Shock and Vibration | Year: 2017

Strong shock waves can be generated by pulse discharge in water, and the characteristics due to the shock wave normal reflection from rigid walls have important significance to many fields, such as industrial production and defense construction. This paper investigates the effects of hydrostatic pressures and perturbation of wave source (i.e., charging voltage) on normal reflection of one-dimensional unsteady flow shock waves. Basic properties of the incidence and reflection waves were analyzed theoretically and experimentally to identify the reflection mechanisms and hence the influencing factors and characteristics. The results indicated that increased perturbation (i.e., charging voltage) leads to increased peak pressure and velocity of the reflected shock wave, whereas increased hydrostatic pressure obviously inhibited superposition of the reflection waves close to the rigid wall. The perturbation of wave source influence on the reflected wave was much lower than that on the incident wave, while the hydrostatic pressure obviously affected both incident and reflection waves. The reflection wave from the rigid wall in water exhibited the characteristics of a weak shock wave, and with increased hydrostatic pressure, these weak shock wave characteristics became more obvious. © 2017 Dong Yan et al.


Lu Y.,Taiyuan University of Technology | Qi X.,Taiyuan University of Technology | Gao C.,Hangzhou Wanxiang Polytechnic
Jixie Qiangdu/Journal of Mechanical Strength | Year: 2017

The surface roughness data of test-pieces with transverse profiles were firstly measured by a roughness profile measuring analyzer. With the help of the Fourier nonlinear approximation the measured data was used to form a roughness function which was superimposed to film thickness equation and a mixed thermal elastohydrodynamic lubrication model for the rolling bearing was then established. Based on the model, 45 sets of numerical calculations were carried out by changing the roughness values under other conditions of the rolling bearing were fixed. Then the two quantitative relationships between the average oil film at the contact point and the roughness as well as the maximum subsurface principal stress and the roughness are respectively established through the regression analysis of the calculation results. © 2017, Editorial Department of JOURNAL OF MECHANICAL STRENGTH. All right reserved.


Xu X.,Taiyuan University of Technology | Xu P.,Taiyuan University of Technology | Hao Y.,Taiyuan University of Technology | Qin W.,Taiyuan University of Technology
Organic Electronics: physics, materials, applications | Year: 2017

Sensing from the ultraviolet–visible to the infrared is bringing more attentions recently. Here, we report the effects of optically generated dipoles within PTB7 layer on photocurrent and photoresponse in single wall carbon nanotube-based photodetectors. The observations in this work provide the direct evidence that optically generated dipoles within the PTB7 layer can be aligned by a built-in field, and then consequently affect dissociation of photo-excited electron-hole pairs in single wall carbon nanotubes. Additionally, PL (photoluminescence) of single wall carbon nanotubes can be appreciably quenched by optically generated dipoles in PTB7 layer. This quenched PL provides further information to back up photodetectivity increasing through dipoles alignment in PTB7 layer. © 2017 Elsevier B.V.


Wang G.,Taiyuan University of Technology | Wang J.,Taiyuan University of Technology
Guti Lixue Xuebao/Acta Mechanica Solida Sinica | Year: 2017

Metal foams are widely used as advanced lightweight construction or kinetic energy absorbers in many industrial fields. Graded metal foam is becoming a research hotspot due to its outstanding designability. The dynamic compressive mechanical behavior of closed-cell aluminum foam with continuous negative density gradient under different impact velocities was investigated using the finite element software ABAQUS. First, the random 3-D Voronoi technique was employed to construct graded closed-cell foam models. Then different impact velocities were applied at the impact end of foam along the negative density gradient direction. Like the uniform foam, three deformation modes, i.e. quasi-static mode, transitional mode and shock mode were observed with the increase of impact velocity. The densification factor was introduced to define the critical velocities of mode transition. A new method was proposed to define the local densification strain by contrasting the nominal stress-strain curves with deformation modes. This method took the effects of relative density and density gradient into account. Deformation maps of impact velocity versus relative density and density gradient were respectively presented for the graded foam. Finally, the effect of density gradient on energy absorption ability was discussed. The finite element simulation results indicated that the first critical velocity was insensitive to the relative density, while the second critical velocity increased with the increase of relative density. The critical velocity decreased with the increase of density gradient. It was found that the smaller the absolute value of density gradient was, the more energy the foam would absorb at the initial stage of deformation under low impact velocity; and the larger the absolute value of density gradient was, the stronger energy absorption ability of the foam material at the initial stage of deformation under high impact velocity would be. These research results could be applied to the design of optimal energy adsorption structure with graded metal foam. © 2017, Editorial Department Chinese Journal of Solid Mechanics. All right reserved.


Luo J.,Taiyuan University of Technology | He X.,Taiyuan University of Technology | Si Z.,Taiyuan University of Technology
High Performance Polymers | Year: 2017

Copolymers based on glassy and rubbery units have been developed to take advantage of both domains to enhance solubility and diffusivity. In this study, a series of gas separation membranes from poly(ether sulfone)s containing ethylene glycol were synthesized via nucleophilic substitution polycondensation. The structures of copolymers were confirmed by proton nuclear magnetic resonance spectroscopy and Fourier transform infrared spectra. The permeability and selectivity of the membranes were studied at different temperatures of 25-55°C and pressures of 0.5-1.5 atm using single gases, such as carbon dioxide (CO2) and nitrogen (N2). Gas permeation measurements showed that copolymers with different content of poly(ethylene glycol) (PEG) exhibited different separation performances. For example, the membrane from polysulfone-PEG-20 containing 20 wt% PEG showed a better performance in terms of ideal selectivity over the other three copolymers membranes. The highest ideal CO2/N2 selectivity was 66.8 with CO2 permeability of 6.4 barrer at 1.5 atm and 25°C. © The Author(s) 2016.


Yu F.,Taiyuan University of Technology | Wang H.,Taiyuan University of Technology | Yuan G.,Taiyuan University of Technology | Shu X.,Taiyuan University of Technology
Applied Physics A: Materials Science and Processing | Year: 2017

Arc melting with nonconsumable tungsten electrode and water-cooled copper crucible was used to fabricate Ti–Cu binary alloys with different Cu contents in an argon atmosphere. The compositions and phase structures of the fabricated alloys were investigated by glow discharge optical emission spectroscopy (GDOES) and X-ray diffraction (XRD). Nanoindentation tests through continuous stiffness measurement were then performed at room temperature to analyze the mechanical behaviors of the alloys. Results indicated that the composition of each Ti–Cu binary alloy was Ti(100−x) Cux (x = 43, 60, 69, and 74 at.%). The XRD analysis results showed that the alloys were composed of different phases, indicating that different Cu contents led to the variations in alloy hardness. The wear tests results revealed that elemental Cu positively affects the wear resistance properties of the Ti–Cu alloys. Nanoindentation testing results showed that the moduli of the Ti–Cu alloys were minimally changed at increasing Cu content, whereas their hardness evidently increased according to the wear test results. © 2017, Springer-Verlag Berlin Heidelberg.


Zhang L.,Taiyuan University of Technology | Xie S.,Shandong University
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2017

We reveal that bilayer polyacene can be the gapped state due to the intralayer Peierls instability. There are six topologically inequivalent Peierls-distorted structures and they are degenerate in energy. The external electric field can tune the Peierls gap and induce the semiconductor-to-metallic phase transitions. The optical conductivity spectra are calculated in an attempt to categorize the Peierls-distorted structures. The strength of the interlayer coupling essentially affects the electronic properties and the optical selection rules. © 2017 Elsevier B.V.


Dong Q.,Taiyuan University of Technology | Tai F.,Taiyuan University of Technology | Lian H.,Taiyuan University of Technology | Zhao B.,Taiyuan University of Technology | And 5 more authors.
Nanoscale | Year: 2017

A significant enhancement in light extraction in organic light-emitting diodes (OLEDs) is realized by using composite hole transport layers (HTLs) with surface carbon-coated magnetic alloy nanoparticles (NPs). Compared to the control device with a standard architecture, the current efficiencies of fluorescent green OLEDs can be enhanced by 47.1% and 48.5% by mixing the surface carbon-coated magnetic FePt (0.5 wt‰) and CoPt (0.5 wt‰) alloy NPs into poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), yielding the maximum values of 5.40 cd A-1 and 5.45 cd A-1, respectively. The presence of an alloy NP-incorporated PEDOT:PSS HTL also acts as an optical out-coupling layer contributing to the efficiency enhancement, accomplished through the collective effects of light-scattering, localized surface plasmon resonance and increased electron trap density induced by magnetic alloy NPs. © The Royal Society of Chemistry 2017.


Wang Y.,Taiyuan University of Technology | Yang Q.,Beijing University of Chemical Technology | Zhong C.,Beijing University of Chemical Technology | Li J.,Taiyuan University of Technology
Applied Surface Science | Year: 2017

Graphene has enormous potential as a membrane-separation material with ultrahigh permeability and selectivity. The understanding of mass-transport mechanism in graphene membranes is crucial for applications in gas separation field. We computationally investigated the capability and mechanisms of functionalized nanoporous graphene membranes for gas separation. The functionalized graphene membranes with appropriate pore size and geometry possess excellent high selectivity for separating CO2/N2, CO2/CH4 and N2/CH4 gas mixtures with a gas permeance of ∼103–105 GPU, compared with ∼100 GPU for typical polymeric membranes. More important, we found that, for ultrathin graphene membranes, the gas separation performance has a great dependence not only with the energy barrier for gas getting into the pore of the graphene membranes, but also with the energy barrier for gas escaping from the pore to the other side of the membranes. The gas separation performance can be tuned by changing the two energy barriers, which can be realized by varying the chemical functional groups on the pore rim of the graphene. The novel mass-transport mechanism obtained in current study may provide a theoretical foundation for guiding the future design of graphene membranes with outstanding separation performance. © 2017 Elsevier B.V.


Wang W.,Harbin Institute of Technology | Yu B.,Harbin Institute of Technology | Yan X.,Guangdong University of Finance and Economics | Yao X.,Taiyuan University of Technology | Liu Y.,Harbin Institute of Technology
Journal of Cleaner Production | Year: 2017

A DEA-RAM model is adopted to study the unified efficiency of innovation's green performance in 29 sectors of China's manufacturing industry over the period of 2005–2012 in this paper. This study provides evidences that innovation in China's manufacturing industry shows a shift to green innovation and contributes increasingly to green growth. However, the lag in the environmental efficiency remains a major constrain for improving innovation's green performance of China. A significant regional disparity exists in the unified efficiency between western and eastern areas of China. The gap in the unified efficiency tends to increase across regions. © 2017 Elsevier Ltd


Zhou R.,Taiyuan University of Technology | Han C.-J.,Taiyuan University of Technology | Wang X.-M.,Taiyuan University of Technology
Journal of Power Sources | Year: 2017

Layered molybdenum disulfide (MoS2) owns graphene-like two-dimensional structure, and when used as the electrode material for energy storage devices, the intercalation of electrolyte ions is permitted. Herein, a simple dipping and drying method is employed to stack few-layered MoS2 nanosheets on a three-dimensional graphene network (3DGN). The structure measurement results indicate that the assembled hierarchical MoS2 nanosheets own expanded interlayer spacing (∼0.75 nm) and are stacked on the surface of 3DGN uncontinuously. The composite can achieve 110.57% capacitance retention after 4000 cycles of galvanostatic charge/discharge tests and 76.73% capacitance retention with increasing the current density from 1 A g−1 to 100 A g−1. Moreover, the asymmetric coin cell supercapacitor using MoS2@3DGN and active carbon as electrode materials is assembled. This device could achieve a working voltage window of 1.6 V along with the power and energy densities of 400.0–8001.6 W kg−1 and 36.43–1.12 Wh kg−1 respectively. The enhanced electrochemical performance can be attributed to: (1) the expanded interlayer spacing of hierarchical MoS2 nanosheets which can facilitate the fast intercalation/deintercalation of electrolyte cations, (2) the uncontinuous deposition of hierarchical MoS2 nanosheets which facilitates more contact between electrolyte and the section of MoS2 nanosheets to provide more gates for the intercalation/deintercalation. © 2017 Elsevier B.V.


Huang X.,Taiyuan University of Technology
Journal of Alloys and Compounds | Year: 2017

During the past decade, lanthanide-doped upconversion luminescent nanoparticles, which are capable of generating shorter-wavelength photons under infrared light excitation, have attracted worldwide attention due to their promising applications in biomedical imaging, solar cells, and display technologies. However, such applications are still harmed by the low photoluminescence quantum yield and narrow excitation bandwidth of upconversion nanoparticles, which can be attributed to the small absorption cross-sections arising from formally forbidden 4f–4f transitions of the dopants (e.g., Yb3+, Er3+, Ho3+ ions). Just recently, a novel class of upconversion nanomaterials with an organic near-infrared dye as sensitizer of lanthanide dopants was developed, which allows for broadband, low-power near-infrared excitation and high overall luminescence quantum yield, making them highly promising as spectral converter for applications in solar cells. © 2016 Elsevier B.V.


Zhu J.,Taiyuan University of Technology | Fu Q.,Taiyuan University of Technology | Xue Y.,Taiyuan University of Technology | Cui Z.,Taiyuan University of Technology
Materials Chemistry and Physics | Year: 2017

Based on the surface pre-melting model, accurate thermodynamic relations of the melting temperature of nanocrystals with different shapes (tetrahedron, cube, octahedron, dodecahedron, icosahedron, nanowire) were derived. The theoretically calculated melting temperatures are in relative good agreements with experimental, molecular dynamic simulation and other theoretical results for nanometer Au, Ag, Al, In and Pb. It is found that the particle size and shape have notable effects on the melting temperature of nanocrystals, and the smaller the particle size, the greater the effect of shape. Furthermore, at the same equivalent radius, the more the shape deviates from sphere, the lower the melting temperature is. The value of melting temperature depression of cylindrical nanowire is just half of that of spherical nanoparticle with an identical radius. The theoretical relations enable one to quantitatively describe the influence regularities of size and shape on the melting temperature and to provide an effective way to predict and interpret the melting temperature of nanocrystals with different sizes and shapes. © 2017 Elsevier B.V.


Yang Z.,Taiyuan University of Technology | Gao M.,Taiyuan University of Technology | Bai Y.,Taiyuan University of Technology | Li F.,Taiyuan University of Technology
Applied Thermal Engineering | Year: 2017

A kinetic model derived from the classical Šesták-Berggren equation was established to simulate the isothermal gasification process of coal char with different partial pressures of H2O, CO2 and their mixtures. The effects of H2O and CO2 on the reaction could be expressed by the kinetic parameters η and φ which represent the conversion corresponding to maximum reaction rate (xmax) influenced by reactant gas and the gas distribution at the active sites, respectively. The results indicate that the relationship between η and xmax can be expressed as xmax = 0.509–0.429η. The parameter φ of co-gasification is superior to that of H2O or CO2 gasification, indicating that the distribution of the gasifying agents during co-gasification is more uniform than that during H2O or CO2 gasification. The synergistic behavior observed during co-gasification was evaluated by the model and it indicates that the interaction between H2O and CO2 results in the improvement of coal physical structure and accelerates the co-gasification reaction rate. Kinetic compensation effect at different partial pressures indicates that the dependence of intrinsic reaction rate on the partial pressures of gasifying agent is gradually weakened as the temperature approaches the isokinetic temperature Tiso for in-situ gasification. It is also confirmed by the nth order reaction rate equation that the reaction order n tends to approach zero when the temperature approaches Tiso. The reaction rate is only affected by the temperature when the gasification temperature exceeds Tiso and the partial pressure of reactant gas is higher than 0.03 MPa which is the minimum pressure required for full coverage of all the active sites. © 2017 Elsevier Ltd


Hu H.,Taiyuan University of Technology
International Journal of Interactive Mobile Technologies | Year: 2016

An online automatic disaster monitoring system can reduce or prevent geological mine disasters to protect life and property. Global Navigation Satellite System receivers and the GeoRobot are two kinds of in-situ geosensors widely used for monitoring ground movements near mines. A combined monitoring solution is presented that integrates the advantages of both. In addition, a geosensor network system to be used for geological mine disaster monitoring is described. A complete online automatic mine disaster monitoring system including data transmission, data management, and complex data analysis is outlined. This paper proposes a novel overall architecture for mine disaster monitoring. This architecture can seamlessly integrate sensors for long-term, remote, and near real-time monitoring. In the architecture, three layers are used to collect, manage and process observation data. To demonstrate the applicability of the method, a system encompassing this architecture has been deployed to monitor the safety and stability of a slope at an open-pit mine in Inner Mongolia.


Liu Y.,Taiyuan University of Technology | Liu S.,Taiyuan University of Technology
Journal of Surfactants and Detergents | Year: 2017

Abstract: In order to restrain moisture re-adsorption of dried lignite, a series of dodecyl based surfactants with various hydrophilic heads including dodecyltrimethylammonium bromide (DTAB), sodium dodecyl sulfonate (SDS), dodecyl nonaethoxyl ether (C12EO9) and a gemini surfactant (G12-2-12) were used to adsorb on lignite surface for wettability modification. The adsorption isotherms and zeta potential were determined to study the adsorption process. Lagergren-first-order and pseudo-second-order kinetics models were used to simulate the adsorption kinetics. The modified lignite was characterized by FTIR spectroscopy, and the wettability of it was evaluated by the wetting heat and moisture re-adsorption ratio. The results indicate that hydrophilic heads of surfactants play an important role in adsorption mechanisms and structures of their adsorption layers on lignite surface, which are responsible for wettability alteration. Four surfactants produce different effects on restraining moisture re-adsorption of lignite: the effect of cationic surfactants is better and worse for anionic surfactant SDS, while the non-ionic surfactant C12EO9 shows intermediate behavior. But with the formation of double-layer adsorption, hydrophilic headgroups of surfactant face outward, which causes hydrophilicity of lignite to rise again. Combining adsorption situations and wettability modification effects, the relationship between molecular orientation of four surfactants on a lignite surface and wettability reversal of lignite are discussed. Graphical abstract: . [Figure not available: see fulltext.] © 2017, AOCS.


Wei Q.,Taiyuan University of Technology | Wei Q.,Shanxi Agricultural University | Sun X.,Taiyuan University of Technology
Advances in Mechanical Engineering | Year: 2016

The diffuser inlet width is a key geometric parameter that affects submersible pump performance. On the basis of diffuser characteristic curve analyses, diffusers with different inlet widths and the same impeller were equipped to construct a submersible pump model through the use of AutoCAD software. The performance curves of the submersible pump, with six diffuser inlet widths, were obtained using computational fluid dynamics method. Simultaneously, the simulation results were tested with the experimental method presented in this article. The results show that the optimum value of the inlet width (b3 = 50 mm) is larger than the experience-based one. With an increase in the inlet width, the optimum operating point of a submersible pump offsets to a larger flow rate. When the guide blade inlet width is approximately 40-55 mm, the submersible pump efficiency is relatively high, approximately 75.9%-83.7% capacity, and the flow rate is approximately 105-135 m3/h. The numerical results of submersible pump performance are higher than those of the test results; however, their change trends have an acceptable agreement with each other. The practical significance is supplied by changing the inlet width of the diffuser to expand the scope of use. ©The Author(s) 2017.


Lan T.,Northwestern Polytechnical University | Yan F.,Taiyuan University of Technology | Lin H.,Northwestern Polytechnical University
Journal of Control Science and Engineering | Year: 2017

In order to improve the traffic condition, a novel iterative learning control (ILC) algorithm with forgetting factor for urban road network is proposed by using the repeat characteristics of traffic flow in this paper. Rigorous analysis shows that the proposed ILC algorithm can guarantee the asymptotic convergence. Through iterative learning control of the traffic signals, the number of vehicles on each road in the network can gradually approach the desired level, thereby preventing oversaturation and traffic congestion. The introduced forgetting factor can effectively adjust the control input according to the states of the system and filter along the direction of the iteration. The results show that the forgetting factor has an important effect on the robustness of the system. The theoretical analysis and experimental simulations are given to verify the validity of the proposed method. © 2017 Tianyi Lan et al.


Liang X.Z.,University of Leicester | Dodge M.F.,Twi Ltd. | Liang W.,Taiyuan University of Technology | Dong H.B.,University of Leicester
Scripta Materialia | Year: 2017

In super duplex stainless steel, austenite-ferrite boundaries are preferential sites for the precipitation of chromium nitride (Cr2N) during heat treatment. In this study, we observed a large number of Cr2N rods were continuously lined up on a thin lamella of M23C6 of 20 nm width along an austenite-ferrite boundary. This observation indicates that M23C6 carbides at the boundary play a significant role in promoting the formation of Cr2N rods. © 2016


Qiuzu L.,Taiyuan University of Technology | Xiaofeng D.,Taiyuan University of Science and Technology | Yanping L.,Taiyuan University of Technology | Xiaojia W.,Taiyuan University of Technology
Journal of Alloys and Compounds | Year: 2017

Gd in Mg-RE liquid alloy has a high solid solubility, which can rapidly decreases with the drop of temperature. Thus the solid solution and aging reinforcement of liquid Mg alloy can be achieved. The micro-structure and mechanical properties of Mg-Gd-Y-Nd-Zr alloy under as-cast and aging state were studies by composition analysis, micro-structure observation and mechanical properties test, and the reinforcement mechanism of mechanical properties was analyzed. Results show that the micro-structure of as-cast alloy is mainly composed of α-Mg matrix and eutectic phase. The dendritic eutectic phase exhibits a discontinuous mesh distribution along the grain boundary. And the average grain size of alloy is about 46 μm. After aging treatment, the average grain size is 52 μm and the eutectic phase can dissolve into α-Mg matrix completely. The massive particle phase distribute in grain boundary and their number increased significantly, which can strengthen the alloy effectively. The tensile strength and yield strength of alloy are improved significantly from as-cast to aging state. But the elongation shows a decreasing trend. The Gd after dissolved into α-Mg matrix can lead to serious lattice distortion, improve the antiphase domain boundary and further improve the alloy yield strength. © 2016 Elsevier B.V.


Chen Y.-C.,University of Michigan | Chen Q.,University of Michigan | Zhang T.,Taiyuan University of Technology | Wang W.,Taiyuan University of Technology | And 2 more authors.
Lab on a Chip - Miniaturisation for Chemistry and Biology | Year: 2017

Biolasers are an emerging technology for next generation biochemical detection and clinical applications. Progress has recently been made to achieve lasing from biomolecules and single living cells. Tissues, which consist of cells embedded in an extracellular matrix, mimic more closely the actual complex biological environment in a living body and therefore are of more practical significance. Here, we developed a highly versatile tissue laser platform, in which tissues stained with fluorophores are sandwiched in a high-Q Fabry-Pérot microcavity. Distinct lasing emissions from muscle and adipose tissues stained respectively with fluorescein isothiocyanate (FITC) and boron-dipyrromethene (BODIPY), and hybrid muscle/adipose tissue with dual staining were achieved with a threshold of only ∼10 μJ mm−2. Additionally, we investigated how the tissue structure/geometry, tissue thickness, and staining dye concentration affect the tissue laser. Lasing emission from FITC conjugates (FITC-phalloidin) that specifically target F-actin in muscle tissues was also realized. It is further found that, despite the large fluorescence spectral overlap between FITC and BODIPY in tissues, their lasing emissions could be clearly distinguished and controlled due to their narrow lasing bands and different lasing thresholds, thus enabling highly multiplexed detection. Our tissue laser platform can be broadly applicable to various types of tissues/diseases. It provides a new tool for a wide range of biological and biomedical applications, such as diagnostics/screening of tissues and identification/monitoring of biological transformations in tissue engineering. © The Royal Society of Chemistry.


Yu G.,Henan University of Technology | Wang G.,Taiyuan University of Technology
Interdisciplinary Sciences: Computational Life Sciences | Year: 2017

Response surface methodology (RSM) was employed to optimize medium components including oxygen vector of n-dodecane of a mutant strain GC-63 of Streptomyces roseosporus NRRL 11379. The two-level Plackett–Burman design (PB factorial design) with fourteen variables including oxygen vector was used to screen the most significant factors affecting antibiotic production. Then, the RSM based on center composite design was used to identify the optimum levels of the significant variables to generate optimal response. Glucose, soybean meal, asparagine and n-dodecane were screened to significantly influence the daptomycin production. The medium composition optimized with response surface methodology was (g/L): glucose, 9.46; soluble starch, 25; dextrin, 12.5; yeast extract, 12.5; soybean meal, 21.34; peptone, 25; casein, 5; asparagine, 2.68; K2SO4, 6; (NH4)2Fe(SO4)2, 2; MgSO4, 1; CaCO3, 5; MnCl2, 0.5; n-dodecane, 7.47 % (v/v). The maximum daptomycin concentration reached 979.36 mg/L which was nearly 2.2-fold higher compared to that in the basal medium, with predicted optimal concentrations in a 7.5-L fermentor. © 2015, International Association of Scientists in the Interdisciplinary Areas and Springer-Verlag Berlin Heidelberg.


Ma N.,Taiyuan University of Technology
Physica B: Condensed Matter | Year: 2017

The Majorana fermions (MFs) were firstly envisioned by Majorana in 1937 as fundamental constituents of nature, whereas experimentally thus far unobserved in the realm of fundamental particles. More recent studies have revealed that the MFs could occur in condensed matter physics as emergent quasiparticle excitations in effectively spinless p-wave topological superconductors (TS). They are shown to behave as effectively fractionalized anyons following non-Abelian braiding statistics rather than the usual Fermi or Bose exchange statistics. This extraordinary property would directly lead to a perpetually coherent and fault tolerant topological quantum computation in 2D systems. Currently the experiments searching for MFs on much more special systems are ongoing and the investigations of MFs' behavior in TS-coupled systems are also been actively pursued, with the goal of deeply understanding the fundamental physics of fractional statistics in nature, and further paving more feasible ways toward a working universal topological quantum computer. © 2017 Elsevier B.V.


Guo Y.,Taiyuan Normal University | Zhang Y.,Taiyuan University of Technology
Journal of Materials Science: Materials in Electronics | Year: 2017

ZnO-MgO-TiO2-CaO(abbreviated as ZMTC) dielectric ceramics were prepared by conventional mixed oxide route. The effects of ZnO-H3BO3(abbreviated as ZH) glass addition on the microstructures and dielectric properties of ZMTC ceramics were investigated. The formation of second phase can be detected at the high addition of ZH (8.0~16.0 wt%). Variation of grain shapes were observed with ZH content increasing. The sintering temperature of ZH-doped ZMTC ceramics can be effectively lowered from 1270 to 950 °C due to liquid phase sintering. The dielectric properties were affected by the amount of ZH addition. At 950 °C for 6 h, ZMTC ceramics with 8.0 wt% ZH possesses excellent dielectric properties: εr = 21.7, Qƒ = 60000 GHz, and TCF = 21.63 ppm/°C. © 2017 Springer Science+Business Media New York


Wang S.,Taiyuan University of Technology | Dong L.,Taiyuan University of Technology | Wang X.,Taiyuan University of Technology
2016 3rd International Conference on Systems and Informatics, ICSAI 2016 | Year: 2016

We discuss a stochastic SIQR epidemic system with vaccination, in this paper. This system does not have any equilibrium points compared with the corresponding deterministic SIQR model, but we explore the asymptotic behaviors of its solutions to the equilibria of the corresponding deterministic SIQR system, and the global existence of positive solution. By I to's formula and constructing proper Lyapunov functions, we prove that the solutions for stochastic SIQR system fluctuate randomly around equilibrium points of the corresponding deterministic SIQR system under some assumptions. At last, numerical simulations are used to verify our conclusions, and we reveal that this class of stochastic SIQR system with vaccination and isolation possesses realistic great significance. © 2016 IEEE.


Wang X.,Taiyuan University of Technology | Dong L.,Taiyuan University of Technology
2016 3rd International Conference on Systems and Informatics, ICSAI 2016 | Year: 2016

A two-species stochastic competitive Lotka-Volterra system with dispersal is studied in this paper. Firstly, we demonstrate that the diffused system has a globally sole and positive solution for any given positive initial conditions via applying ltd formula. Then, we discuss the stochastic final bounded ness of the solution. Finally, we obtain a sufficient condition for extinction. © 2016 IEEE.


He X.,China Institute of Technology | Yan Z.,Taiyuan University of Technology | Liang H.,China Institute of Technology | Wei Y.,Taiyuan University of Technology
Journal of Materials Engineering and Performance | Year: 2017

The potentiodynamic polarization test and slow strain rate tensile test were carried out in 3.5 wt.% Na2SO4 solution with different pH values (2, 7, and 12). It was found that the SCC susceptibility of AZ31 magnesium alloy in 3.5 wt.% Na2SO4 solution was deteriorated significantly with the decreasing pH. This was consistent with the electrochemical properties. There were filiform corrosion forms on the specimen surface after slow strain rate tensile test in 3.5 wt.% Na2SO4 solution, which indicated the characteristics of general corrosion. Moreover, there were multiple stress corrosion crack initiation sources. The SCC fracture of AZ31 magnesium alloy in air was a mix type, while it was cleavage fracture in 3.5 wt.% Na2SO4 solution. © 2017 ASM International


Li D.,Taiyuan University of Technology | Wu G.,Taiyuan University of Technology | Zhao J.,Taiyuan University of Technology | Niu W.,Taiyuan University of Technology | Liu Q.,Taiyuan University of Technology
Journal of Information Processing Systems | Year: 2017

Effective identification of wireless channel in different scenarios or regions can solve the problems of multipath interference in process of wireless communication. In this paper, different characteristics of wireless channel are extracted based on the arrival time and received signal strength, such as the number of multipath, time delay and delay spread, to establish the feature vector set of wireless channel which is used to train backpropagation (BP) neural network to identify different wireless channels. Experimental results show that the proposed algorithm can accurately identify different wireless channels, and the accuracy can reach 97.59%. © 2017 KIPS.


Zhu F.,Taiyuan University of Technology | Li L.,Taiyuan University of Technology | Xing J.,Taiyuan University of Technology
Journal of Hazardous Materials | Year: 2017

Microwave-assisted inverse emulsion polymerization method was used to prepare Cd(II) imprinted polymer (IIP) by using β-cyclodextrin (β-CD) and acrylamide (AM) as functional monomer, epichlorohydrin (ECH) as crossing-linking agent, ammonium persulfate as initiator. The Cd(II) imprinted polymer was characterized by SEM, FTIR and TGA. The influences of initial concentration of Cd(II), pH values, temperature, time and competitive ions on adsorption capacity and recognition properties are investigated. Under the optimal conditions, the adsorption capacity could reach 107 mg/g. Furthermore, pseudo first order kinetic model, pseudo second order kinetic model and intra-particular diffusion model were used to describe the adsorption kinetic behavior. Results showed that the pseudo-second-order model (R2 0.9928–0.9961) had the best agreement with the experimental data. Langmuir adsorption isotherm model described the experimental data well, which indicated that adsorption was mainly monolayer absorption. Moreover, the study of adsorption thermodynamics (ΔG0 < 0, ΔH0 > 0, ΔS0 > 0) suggested that the adsorption process was a spontaneous and endothermic process. Competitive selectivity experiment revealed that imprinted polymer could selectively recognize Cd(II). It provides a new idea for removing Cd(II) from aqueous solution. © 2016 Elsevier B.V.


Liu G.,Taiyuan University of Technology | Gao X.,Taiyuan University of Technology | Wang K.,Taiyuan University of Technology | He D.,Taiyuan University of Technology | Li J.,Taiyuan University of Technology
Nano Research | Year: 2017

The design and fabrication of low-cost, high-efficiency, and stable oxygen-evolving catalysts are essential for promoting the overall efficiency of water electrolysis. In this study, mesoporous Ni1–xFexOy (0 ≤ x ≤ 1, 1 ≤ y ≤ 1.5) nanorods were synthesized by the facile thermal decomposition of Ni–Fe-based coordination polymers. These polymers passed their nanorod-like morphology to oxides, which served as active catalysts for oxygen evolution reaction (OER). Increasing the Fe-doping amount to 33 at.% decreased the particle size and charge-transfer resistance and increased the surface area, resulting in a reduced overpotential (~302 mV) at 10 mA/cm2 and a reduced Tafel slope (~42 mV/dec), which were accompanied by a far improved OER activity compared with those of commercial RuO2 and IrO2 electrocatalysts. At Fe-doping concentrations higher than 33 at.%, the trend of the electrocatalytic parameters started to reverse. The shift in the dopant concentration of Fe was further reflected in the structural transformation from a NiO (<33 at.% Fe) rock-salt structure to a biphasic NiO/NiFe2O4 (33 at.% Fe) heterostructure, a NiFe2O4 (66 at.% Fe) spinel structure, and eventually to α-Fe2O3 (100 at.% Fe). The efficient water-oxidation activity is ascribed to the highly mesoporous one-dimensional nanostructure, large surface area, and optimal amounts of the dopant Fe. The merits of abundance in the Earth, scalable synthesis, and highly efficient electrocatalytic activity make mesoporous Ni–Fe binary oxides promising oxygen-evolving catalysts for water splitting. [Figure not available: see fulltext.] © 2016 Tsinghua University Press and Springer-Verlag Berlin Heidelberg


Chen X.,Taiyuan University of Technology | Lv Y.,Taiyuan University of Technology | Liu Y.,Taiyuan University of Technology | Ren R.,Taiyuan University of Technology | Zhao J.,Taiyuan University of Technology
International Journal of Hydrogen Energy | Year: 2017

Photofermentative hydrogen production from glucose was investigated using the mixed photoheterotrophic culture (NG07). High-throughput sequencing was applied to describe the characteristics of the diversity of the microbial community. Bioinformatic analysis of the sequencing result showed that photosynthetic bacteria were dominant in the microbial populations. Several key parameters were investigated by NG07 to assess biohydrogen production. Under optimal condition with 70 mM glucose, 5.0 mg/L Fe2+, and 35 °C temperature, a high hydrogen production rate (HPR) was 136.0 ± 5.6 mL/L/h, which is higher than previous reports. That was the first time the study had found the mixed microbial community could resist the high temperature of 45 °C for photohydrogen generation, and increasing glucose concentration would result in higher hydrogen yield. These results implied that the mixed photoheterotrophic culture had a high temperature tolerance and the possibility of bio-hydrogen production in high temperature region. © 2016 Hydrogen Energy Publications LLC


Shen L.,Anhui University of Science and Technology | Zhu J.,Anhui University of Science and Technology | Liu L.,Anhui University of Science and Technology | Wang H.,Taiyuan University of Technology
Powder Technology | Year: 2017

In order to improve the flotation recovery of fine kaolinite, mixed dodecylamine chloride/fatty acid was used as collector in kaolinite flotation process. The performance of dodecylamine chloride/fatty acid mixture collector on kaolinite flotation was investigated using flotation test and computational method. Surface tension measurement, contact angle measurement and image analysis were also used to study the flotation behavior of dodecylamine chloride and mixture collectors. The flotation results showed that much higher kaolinite flotation recovery was obtained in the presence of dodecylamine chloride/octanoic acid mixture compared with that in the presence of dodecylamine chloride alone. Surface tension measurements indicated that the mixed dodecylamine chloride/octanoic acid collector was more efficient at decreasing the air–water interfacial tension. Molecular dynamics simulation showed that the octanoic acid molecules were interleaved among dodecylamine chloride ions and co-adsorbed at the kaolinite (001) surface. The relative concentration of water molecules near kaolinite (001) surface further decreased in the presence of dodecylamine chloride/octanoic acid compared with that in the presence of dodecylamine chloride alone, which indicated a much stronger hydrophobicity of the kaolinite (001) surface. © 2017 Elsevier B.V.


Zhang R.,Taiyuan University of Technology | Peng M.,Taiyuan University of Technology | Wang B.,Taiyuan University of Technology
Catalysis Science and Technology | Year: 2017

The catalytic selectivity, the functions of a TiO2 support and promoter, and the mechanism of ethanol synthesis from syngas on a Rh/TiO2 model catalyst have been fully identified. Our results show that all species preferentially interact with Rh7 clusters of a Rh/TiO2 catalyst, rather than the support and cluster-support interface. CO → CHO → CH2O → CH3O is an optimal pathway. CH3 formed via the CH3O → CH3 + O route is the most favored CHx (x = 1-3) monomer, and this route is more favorable than methanol formation by CH3O hydrogenation; CO insertion into CH3 can then form CH3CO, followed by successive hydrogenation to ethanol. Methane is formed by CH3 hydrogenation. The Rh/TiO2 catalyst exhibits better catalytic activity and selectivity toward CH3 than CH3OH formation. Starting from the CH3 species, CH4 formation is more favorable than CH3CO formation; thus, ethanol productivity and selectivity on a Rh/TiO2 catalyst with a support is determined only by CH4 formation, which is similar to that on a pure Rh catalyst without a support. Introducing an Fe promoter into the Rh/TiO2 catalyst effectively suppresses methane production, and promotes CH3CO formation. Therefore, compared to a pure Rh catalyst without a support, the TiO2 support serves only to promote the activity and selectivity of CH3 formation, and provide more CH3 species for ethanol formation; methane formation is independent of the Rh catalyst support, and depends only on the promoter. In order to achieve high ethanol productivity and selectivity, an effective Rh-based catalyst must contain a suitable combination of supports and promoters, in which the promoter, M, should have characteristics that draw the d-band center of the MRh/TiO2 catalyst closer to the Fermi level compared to the Rh7/TiO2 catalyst; as a result, the MRh/TiO2 catalyst can suppress CH4 production and facilitate C2 oxygenate formation. © The Royal Society of Chemistry 2017.


Yang H.-W.,Taiyuan University of Technology | Wang Z.-H.,Taiyuan University of Technology | Jin X.-C.,Taiyuan University of Technology
Gaoya Wuli Xuebao/Chinese Journal of High Pressure Physics | Year: 2017

In this work the constraint function of concrete was regarded as the distribution load associated with the transverse load, and the yield response of projectiles under the compressive and bending load was studied using the free-free beam theory, with the main parameters of the impact of the asymmetric transverse load examined. It was found that the projectiles can be easily bent as a result of greater asymmetric mass loss, greater difference in static resistance between the grout and the aggregate, and sharper projectiles, and projectiles subjected to the transverse impact load can be considered as the response of the cantilever beam without an axial constraint. In addition, the diabasis of the plastic hinge and the formation process of the J-shaped trajectory was analysed. © 2017, Editorial Board of Chinese Journal of High Pressure Physics. All right reserved.


Wang B.,Taiyuan University of Technology | Zhang H.,Taiyuan University of Technology | Chen Y.,Hexi University | Tan L.,Lanzhou University
European Physical Journal D | Year: 2017

Abstract: We have investigated tunneling characteristics of Bose-Einstein condensates (BECs) in a triple-well potential coupled to a high finesse optical cavity within a mean field approach. Due to the intrinsic atom-cavity field nonlinearity, several interesting phenomena arise which are the focuses of this work. In the dynamical process, an extensive numerical simulation of localization of the BECs for atoms initially trapped in one-, two-, and three-wells are performed for the symmetric and asymmetric cases in detail. It is shown that the the transition from the oscillation to the localization can be modified by the cavity-mediated potential, which will enlarge the regions of oscillation. With the increasing of the atomic interaction, the oscillation is blocked and the localization emerges. The condensates atoms can be trapped either in one-, two-, or in three wells eventually where they are initially uploaded for certain parameters. In particular, we find that the transition from the oscillation to the localization is accompanied with some irregular regime where tunneling dynamics is dominated by chaos for this cavity-mediated system. Graphical abstract: [Figure not available: see fulltext.] © 2017, EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.


Wen X.,Taiyuan University of Technology | Ding J.,Taiyuan University of Technology | Yan G.,Taiyuan University of Technology
Proceedings - 2016 9th International Congress on Image and Signal Processing, BioMedical Engineering and Informatics, CISP-BMEI 2016 | Year: 2016

In soft sensor applications, the prediction using only relevant variables significantly improves model accuracy and decreases computational costs. This paper proposed a new method for variable selection based on random vector functional-link (RVFL) neural network model. This method removes input nodes from variable set according to an exclusion criterion by backward selection. Then the remaining weights are adjusted by keeping network output unchanged instead of retraining the network. Finally, the algorithm outputs a set containing the input variables which are ordered in a selection rank. Different methods are applied to several datasets. The results validates that the proposed method selects the lowest number of variables and achieves the satisfactory performance. © 2016 IEEE.


Gao L.,Dalian University of Technology | Wang Y.,Dalian University of Technology | Wang J.,Taiyuan University of Technology
Proceedings - 2016 9th International Congress on Image and Signal Processing, BioMedical Engineering and Informatics, CISP-BMEI 2016 | Year: 2016

Recently, a directed graph model was presented to crowd counting in videos, and people flow was viewed as an integer flow on the constructed graph. The authors show that the network flow constraints on the graphs help to obtain consistent counting results. In this paper, we improve their work from two aspects. First, we design block histogram features for each group of people. Second, we simplify their directed graphs to contracted graphs by contracting all cut arcs. Since the network flow constraints on original graphs are equivalence to that on contracted ones, we propose a quadratic programming method with network flow constraints on contracted graphs to refine the crowd counting results. At last, experiments show that our block histogram features can deal better with perspective distortion problems and our approach obtains outstanding performance on PETS 2009 dataset. © 2016 IEEE.


Qiao J.,Taiyuan University of Technology | Qiao J.,Taiyuan University of Science and Technology | Zhang X.,Taiyuan University of Technology
2016 IEEE International Conference on Information and Automation, IEEE ICIA 2016 | Year: 2016

The design of measurement matrices is one of the key contents of the compressed sensing (CS) theory. This paper constructs a new dual-structured measurement matrix-unit array + random matrix, by combining the advantages of the random measurement matrices with high recovery probability and the structured measurement matrices of low storage. The experiments show that the reconstruction errors can be gotten lower through using the measurement matrix designed than those of the simple application of the random measurement matrix. Then a method of sub-frame overlapping is proposed for reconstructing the entire signal, which can remove large errors caused by unit array in the measurement matrix, and ensure the stability of the whole signal reconstruction. Simulation results demonstrate that the signal to noise ratio (SNR) is increased significantly and the reconstruction performance of signal is improved remarkably. © 2016 IEEE.


Chen Z.,CAS Shanghai Institute of Ceramics | Gao Y.,CAS Shanghai Institute of Ceramics | Gao Y.,Shanghai University | Kang L.,Taiyuan University of Technology | And 4 more authors.
Journal of Materials Chemistry A | Year: 2014

A simulation of the optical properties of nanocomposite coatings derived from VO2 nanoparticles (NPs) shows that the nanocomposite coatings have advantages over pure VO2 thin films in their solar energy modification ability (ΔTsol) and luminous transmittance (T lum). These nanocoatings rely on fine quality VO2 NPs; methods to prepare NPs for this purpose are yet to be developed. By studying the formation mechanism of VO2 NPs, the NP preparation process was optimized, and fine crystal quality VO2 NPs with diameters from 25-45 nm were synthesized. The highest latent heat of these VO2 NPs is 43 J g-1, which is considerably higher than the 25 J g-1 reported previously and close to the 51 J g-1 of bulk VO2, which indicates that these VO2 NPs are highly crystalline. These NPs showed an asymmetrical phase transition and increased insulator-metal transition (IMT) temperatures. According to our results, the size of particles is not the only reason that should be responsible for the increased IMT temperatures. The high-quality NPs were dispersed in polyurethane (PU) and coated on polyethylene terephthalate (PET). The relationship between the solar energy modification ability (ΔTsol) and the luminous transmittance (Tlum) was studied by experiments and simulation. Although the best experimental values of ΔTsol = 22.3% and Tlum = 45.6% are still lower than the simulation results of ΔTsol = 23.7% and Tlum = 32.4%, these values represent the best for reported VO2 smart films or coatings. © 2014 The Royal Society of Chemistry.


Jing L.,Taiyuan University of Technology | Jing L.,National University of Singapore | Wang Z.,Taiyuan University of Technology | Shim V.P.W.,National University of Singapore | Zhao L.,Taiyuan University of Technology
International Journal of Impact Engineering | Year: 2014

The deformation/failure modes and blast resistance of cylindrical sandwich shells comprising two aluminum face-sheets and an aluminum foam core, subjected to air blast loading, were investigated experimentally. Specimens of two different radii of curvature and geometrical configurations, clamped along their peripheries, were studied. A four-cable ballistic pendulum system was employed to measure the impulse imparted to the specimens. Typical deformation/failure modes were classified and analyzed; the effects of face-sheet thickness, core relative density, arrangement of foam core layers of different densities, specimen curvature and mass of charge on the structural response were also examined. The results indicate that both the deformation/failure modes and the structural response of the shells are sensitive to the geometrical configurations and blast impulse. Various failure modes - indentation or tearing of the front face-sheet, collapse of the core, severe inelastic deformation or tearing of the rear face-sheet, and failure between the face-sheets and foam core, were observed. The findings are useful for validating theoretical predictions, as well as to guide application of cellular metal sandwich structures for blast protection purposes. © 2014 Published by Elsevier Ltd.


Su Q.,Zhejiang Normal University | Su Q.,Taiyuan University of Technology | Du G.,Zhejiang Normal University | Zhang J.,Zhejiang Normal University | And 5 more authors.
ACS Nano | Year: 2014

The comprehension of fundamental electrochemical behavior and sodiation mechanism is critical for the design of high-performance electrode materials for sodium-ion (Na-ion) batteries. In this paper, the electrochemical sodiation process and microstructure evolution of individual Co9S 8-filled carbon nanotubes (CNTs) have been directly visualized and studied using in situ transmission electron microscopy. Upon the first sodiation, a reaction front propagates progressively along the filling nanowire, causing the filled CNT to inflate. The filled CNTs behave differently depending on their structures and the magnitude of the sodiation voltage. For a Co 9S8-filled CNT with an open end, the sodiated Co 9S8 filler shows a substantial axial elongation of 120.8% and a small radial swelling due to the extrusion of CNT walls. In contrast, the closed CNT shows a major radial expansion of 40.6% and a small axial elongation because of the mechanical confinement of the carbon shells. After sodiation, the spacing between the carbon shells increases from 3.4 to 3.8 Å due to the Na+-ion insertion and the single-crystalline Co9S 8 filler converts to numerous Co nanograins dispersed in a Na 2S matrix. Compared with the gentle microstructure evolution of the CNT under small charging voltage, a strong electrochemical reaction accompanying drastic swelling and fracturing of CNT shells is observed for the CNT electrode under large charging voltage. Our observations provide direct evidence and important insights for the electrochemical process of CNT-based composite materials in Na-ion batteries. © 2014 American Chemical Society.


Su Q.,Zhejiang Normal University | Li J.,Zhejiang Normal University | Zhong G.,Zhejiang Normal University | Du G.,Zhejiang Normal University | And 2 more authors.
Journal of Physical Chemistry C | Year: 2011

We present a one-step chemical vapor deposition method to prepare iron/nickel sulfide nanostructures-filled carbon nanotubes (CNTs) by pyrolysis of dimethyl sulfide on stainless steel substrate. Dimethyl sulfide is used as the carbon and sulfur source, and the stainless steel substrate acts as both the catalyst and support. The as-grown products were characterized using scanning electron microscopy, transmission electron microscopy, and X-ray diffraction, and the results demonstrate that the encapsulated compounds in CNTs are Fe 7S8 and Ni17S18 with hexagonal crystal structure. The possible growth mechanism is proposed. The complex permittivity and permeability of the CNT composites were measured at a frequency range of 2-18 GHz, and the microwave-absorbing performance was analyzed. With a matching thickness of 2 mm, the maximum reflection loss is about -29.58 dB at 14.80 GHz for the absorber. The bandwidth corresponding to the reflection loss at -10 dB is more than 5.58 GHz. The strong reflection loss is mainly caused by the magnetic loss originating from the encapsulated two-component sulfide nanostructures. © 2011 American Chemical Society.


Su Q.,Zhejiang Normal University | Su Q.,Taiyuan University of Technology | Xie J.,Zhejiang University | Zhang J.,Zhejiang Normal University | And 3 more authors.
ACS Applied Materials and Interfaces | Year: 2014

Metal sulfides are a type of potential anode materials for lithium-ion batteries (LIBs). However, their electrochemical behaviors and mechanism during the charge and discharge process remain unclear. In the present paper, we use CoS2 as a model material to investigate their electrochemical process using in situ transmission electron microscopy (TEM). Two kinds of reaction behaviors are revealed. The pure CoS2 particles show a side-to-side conversion process, in which large and anisotropic size expansion (47.1%) occurs that results in the formation of cracks and fractures in CoS2 particles. In contrast, the CoS2 particles anchored on reduced graphene oxide (rGO) sheets exhibit a core-shell conversion process involving small and homogeneous size expansion (28.6%) and few fractures, which attributes to the excellent Li+ conductivity of rGO sheets and accounts for the improved cyclability. Single-crystalline CoS2 particle converts to Co nanocrystals of 1-2 nm embedded within Li2S matrix after the first lithiation. The subsequent electrochemical reaction is a reversible phase conversion between Co/Li2S and CoS2 nanocrystals. Our direct observations provide important mechanistic insight for developing high-performance conversion electrodes for LIBs. © 2014 American Chemical Society.


Meng Q.S.,Taiyuan University of Technology | Fan W.H.,Taiyuan University of Technology | Chen R.X.,Taiyuan University of Technology | Munir Z.A.,University of California at Davis
Journal of Alloys and Compounds | Year: 2010

Field-activated pressure-assisted process was applied to fabricate "pure" and doped iron disilicide (FeSi2, FeSi2Ge0.01, and FeSi2Cu0.1) by reactive sintering from elemental powders. The products has an average grain size of about 0.3 μm. Significantly lower thermal conductivity measured on these materials provides a figure of merit, ZT of 28.50 × 10-4 in the temperature range of 330-450 K, a value that represents a 17.1-47.2% increase over that published on materials prepared by other methods. © 2009 Elsevier B.V.


Zhang H.-X.,Tarim University | Bai H.-J.,Tarim University | Dong X.-S.,Taiyuan University of Technology | Wang Z.-Z.,Taiyuan University of Technology
Fuel Processing Technology | Year: 2012

Enhanced desulfurizing flotation of different size fractions of high sulfur coal was investigated using the sonoelectrochemical method. The supporting electrolyte used in this process was calcium hydroxide and the additive was anhydrous ethanol. The effects of treatment conditions on desulfurization were studied by a single-factor method. The conditions include anhydrous ethanol concentration, sonoelectrolytic time, current density, and ultrasound intensity. For the coal samples with different size fractions, the optimal experimental conditions for anhydrous ethanol concentration, sonoelectrolytic time, current density, and ultrasound intensity, respectively, are achieved. Under optimal conditions, the raw and treated coals were analyzed by infrared spectroscopy and a chemical method. Pyritic sulfur, organic sulfur, and ash are partially removed. Compared with different size fractions coal, desulfurizing flotation of high sulfur coal by sonoelectrochemistry is an effective technology. Crown Copyright © 2012 Published by Elsevier B.V. All rights reserved.


Zhao C.,University of Hertfordshire | Chen Y.K.,University of Hertfordshire | Chen Y.K.,Taiyuan University of Technology | Ren G.,University of Hertfordshire
Tribology Transactions | Year: 2013

This article presents an investigation on the potential tribological properties of water-based cerium dioxide nanofluids. Nanofluids with different nanoparticle concentrations were prepared in a materials laboratory. A stable dispersion of nanoparticles in the fluids was achieved with an appropriate percentage of the surfactant sorbitan monostearate. The stability of particle dispersion was studied using zeta potential measurement. Additive conglomerate size in the nanofluids was measured using dynamic light scattering. It was observed that the dispersibility of nanoparticles played an important role in the frictional properties of the nanofluids. The tribological properties of the water-based nanofluids were evaluated using a pin-on-disc tester under different loading conditions. A significant improvement in the tribological properties of the waterbased cerium dioxide nanofluids was observed. The worn surfaces of the contact elements were characterized using scanning electron microscopy (SEM) and a nanotester. According to the test results, the significant reductions in the friction coefficients and antiwear properties of water-based cerium dioxide nanofluids were attributed to the deposition of nanoparticles on worn contact surfaces. © Society of Tribologists and Lubrication Engineers.


Li G.,Taiyuan University of Technology | Li G.,Buskerud and Vestfold University College | Chen X.,Buskerud and Vestfold University College
Applied Physics A: Materials Science and Processing | Year: 2012

Charge injection behaviours in silicon nitride of an Al/Si 3N4/n-Si metal-insulator-semiconductor (MIS) device are systematically studied before and after applying different high constant DC bias conditions with the aim of controlling charge accumulation in the dielectric when a high actuation voltage is applied.We found that both polarity and magnitude of charge accumulation in silicon nitride depend on the biasing direction. Charge injection from the semiconductor to the silicon nitride always dominates over charge injection from the Al electrode to the silicon nitride. Negative charge accumulation happens in silicon nitride when the Al electrode is positively biased, and positive charge accumulation occurs in silicon nitride when the Al electrode is negatively biased. The positive charge accumulation is much bigger than the negative charge accumulation under the same magnitude of stress voltage. Furthermore, the experimental results also show that the charge injection level exponentially increases with the applied voltage across the silicon nitride. These observed experimental results can be well explained by a modified Fowler-Nordheim tunnelling charge injection model, which takes into account the roles of both electrons and holes in the process of charge injection. © Springer-Verlag Berlin Heidelberg 2012.


Su Q.,Zhejiang Normal University | Zhong G.,Zhejiang Normal University | Li J.,Zhejiang Normal University | Du G.,Zhejiang Normal University | And 2 more authors.
Applied Physics A: Materials Science and Processing | Year: 2012

Fe/Fe 3C-functionalized carbon nanotubes (CNTs) have been prepared by the floating catalyst chemical vapor-deposition method. It is demonstrated that the Fe and Fe 3C nanostructures are both encapsulated in the CNTs or decorated on the surface of CNTs. The Fe/Fe 3C content in the composites can easily be adjusted by changing the ferrocene concentration in the preparation. The electromagnetic properties of the CNTs have been evaluated in the frequency range of 2-18 GHz, and the nanocomposites exhibit excellent microwave absorbing performance. The CNT composites with higher Fe/Fe 3C content show enhanced microwave reflection losses. The significant influence of the Fe/Fe 3C nanostructures on the microwave absorption is realized by tuning the characteristic impedance of the nanocomposites. With increasing thickness, the maximum reflection loss peak shifts to lower frequency. The microwave absorbing performance of the composites is mainly caused by dielectric loss, resulting from the continuous CNT networks with excellent electrical conductivity. © 2011 Springer-Verlag.


Du J.,Taiyuan University of Technology | Zhao R.,Shanxi Kunming Tobacco Ltd Liability Company | Xue Y.,Taiyuan University of Technology
Journal of Chemical Thermodynamics | Year: 2012

Thermodynamic properties and equilibrium constant of reaction in nanosystems were analyzed theoretically. The effects of sizes of nano-CuO on thermodynamic properties and equilibrium constant were studied using the reaction of nano-copper oxide and sodium bisulfate as a system. The experimental results indicate that with the sizes of reactant decreasing, the molar Gibbs free energy (ΔrGm), the molar enthalpy (ΔrHm) and the molar entropy (Δ rSm) decrease, but the equilibrium constant (K) increases and there are linear trends between the reciprocal of sizes for nano-CuO and the values of ΔrGm, ΔrHm, ΔrSm and Ln K, which are in agreement with the theoretical analysis. © 2011 Elsevier Ltd. All rights reserved.


Su Q.,Zhejiang Normal University | Su Q.,Taiyuan University of Technology | Du G.,Zhejiang Normal University | Zhang J.,Zhejiang Normal University | And 6 more authors.
ACS Nano | Year: 2013

Carbon nanotube (CNT)-encapsulated metal sulfides/oxides are promising candidates for application as anode materials in lithium ion battery (LIB), while their electrochemical behavior and mechanism still remain unclear. A comprehensive understanding of the lithiation mechanism at nanoscale of this type of composites will benefit the design and development of high-performance LIB materials. Here, we use Co9S8/Co nanowire-filled CNTs as a model material to investigate the lithium storage mechanism by in situ transmission electron microscopy. For a Co9S8/Co nanowire-filled closed CNT, the reaction front propagates progressively during lithiation, causing an axial elongation of 4.5% and a radial expansion of 32.4%, while the lithiated nanowire core is still confined inside the CNT. Contrastingly, for an open CNT, the lithiated Co9S8 nanowire shows an axial elongation of 94.2% and is extruded out from the open CNT. In particular, a thin graphite shell is drawn out from the CNT wall by the extruded lithiated Co9S8. The thin graphite shell confines the extruded filler and protects the filler from pulverization in the following lithiation-delithiation cycles. During multiple cycles, the Co segment remains intact while the Co9S8 exhibits a reversible transformation between Co9S8 and Co nanograins. Our observations provide direct electrochemical behavior and mechanism that govern the CNT-based anode performance in LIBs. © 2013 American Chemical Society.


Jing L.,Taiyuan University of Technology | Jing L.,National University of Singapore | Xi C.,Taiyuan University of Technology | Wang Z.,Taiyuan University of Technology | Zhao L.,Taiyuan University of Technology
Materials and Design | Year: 2013

The dynamic response, energy absorption capability, and deformation and failure of clamped aluminum face-sheet cylindrical sandwich shells with closed-cell aluminum foam cores were investigated numerically by impacting the shells at central area with metallic foam projectiles in this paper. Typical deformation/failure modes and deflection response of sandwich shells, obtained from the experiments, were employed here to validate the numerical simulation. Numerical results indicate that the shock resistance of sandwich shells could be enhanced significantly by optimizing their geometrical configurations; the thickness of back face-sheet has a greater contribution than that of front face-sheet. Increasing of impact velocity and decreasing of face-sheet thickness, core relative density and curvature radius can enhance the energy absorption capability of sandwich shells. The initial curvature of sandwich shells may induce easily tearing failure along their circumferential directions. These findings can guide well the theoretical study and optimal design of metallic sandwich structures subjected to impulsive loading. © 2013 Elsevier Ltd.


Yuan W.,Zhejiang Normal University | Xie D.,Zhejiang Normal University | Dong Z.,Zhejiang Normal University | Su Q.,Taiyuan University of Technology | And 3 more authors.
Materials Letters | Year: 2013

Novel porous Co3O4 polyhedral architectures have been successfully prepared by combining a facile hydrothermal synthesis of uniform cobalt oxalate precursors with subsequent heat treatment. The Co 3O4 products are in truncated hexahedral shape, and are composed of many interconnected nanoparticles and a large number of macro-/mesopores. When tested as an anode material for lithium-ion battery, the porous polyhedral Co3O4 presents an initial discharge capacity of 1546 mA h g-1, and maintains a reversible capacity of 432 mA h g-1 after 45 discharge/charge cycles. The enhanced lithium-storage performance can be attributed to the unique porous architecture, which provides the structural flexibility for volume change and the routes for fast Li+ diffusion. © 2013 Elsevier B.V.


Jing L.,Taiyuan University of Technology | Jing L.,National University of Singapore | Wang Z.,Taiyuan University of Technology | Zhao L.,Taiyuan University of Technology
Composite Structures | Year: 2013

Deformation/failure modes, blast resistance and energy absorption of metallic cylindrical sandwich shells with closed-cell aluminum foam cores were investigated in this paper. A brief of experimental result on the dynamic response of blast-loaded sandwich shells was firstly reported. Based on the experiments, corresponding finite element simulations have been undertaken by employing the LS-DYNA software. Numerical simulation results show a good agreement on the deformation/failure modes and back face-sheet center-point deflection of specimens, with those of experimental results. Results indicate that the deformation/failure, deflection response and energy absorption of sandwich shells are sensitive to the loading intensity and geometric configuration. Energy absorption capability of specimens is monotonically increasing and decreasing with the increase of impulse level and core relative density, respectively. However, it does not change monotonically with the face-sheet thickness of specimens. These simulation findings are worthy of the theoretical study and optimal design of metallic sandwich structures under air blast loading. © 2012 Elsevier Ltd.


Zhang Z.-Q.,Institute of High Performance Computing of Singapore | Zhang Z.-Q.,National University of Singapore | Liu G.R.,University of Cincinnati | Liu G.R.,Taiyuan University of Technology
Engineering Analysis with Boundary Elements | Year: 2014

Node-based and edge-based smoothed FEM (NS-FEM and ES-FEM), and α-FEM are extended to solve nonlinear problems. The nonlinear strain field is smoothed using the gradient smoothing. The continuous scalar scaling factor α enables the α-FEM continuously transforming from overestimated model to underestimated model. Numerical examples reveal that ES-FEM is a robust and stable method with high accuracy and computational efficiency for nonlinear problems. The exact solution in strain energy of force driven problems can be bounded by NS-FEM and FEM. The α-FEM can also be "tuned" to find nearly exact solution to nonlinear mechanics problems of solids of complicated geometry. © 2014 Elsevier Ltd. All rights reserved.


Shen J.,Swinburne University of Technology | Lu G.,Nanyang Technological University | Zhao L.,Taiyuan University of Technology | Zhang Q.,Beijing Institute of Technology
Engineering Structures | Year: 2013

The response of sandwich tubes under internal explosive loading was investigated experimentally, numerically and analytically in this paper. Experiments were conducted first to capture the fundamental deformation and failure patterns and they served as a basis of validation for both the FE and analytical models. Further detailed deformation and blast loading history were revealed by the FE model. An explicit analytical solution for the deformation of sandwich tubes under blast loading has been worked out and used to obtain the optimum sandwich configurations, which would outperform their corresponding monolithic tubes. © 2011 Elsevier Ltd.


Wang W.,Taiyuan University of Technology | Hao Y.,Taiyuan University of Technology | Cui Y.,Taiyuan University of Technology | Tian X.,Taiyuan University of Technology | And 5 more authors.
Optics Express | Year: 2014

Metal nanogratings as one of the promising architectures for effective light trapping in organic photovoltaics (OPVs) have been actively studied over the past decade. Here we designed a novel metal nanowall grating with ultra-small period and ultra-high aspect-ratio as the back electrode of the OPV device. Such grating results in the strong hot spot effect in-between the neighboring nanowalls and the localized surface plasmon effect at the corners of nanowalls. These combined effects make the integrated absorption efficiency of light over the wavelength range from 400 to 650 nm in the active layer for the proposed structure, with respect to the equivalent planar structure, increases by 102% at TM polarization and by 36.5% at the TM/TE hybrid polarization, respectively. Moreover, it is noted that the hot spot effect in the proposed structure is more effective for ultra-thin active layers, which is very favorable for the exciton dissociation and charge collection. Therefore such a nanowall grating is expected to improve the overall performance of OPV devices. © 2014 Optical Society of America.


Yu J.,Shenyang Aerospace University | Yu J.,University Of Science And Technology Liaoning | Yin F.,Shenyang Aerospace University | Yin F.,University Of Science And Technology Liaoning | And 3 more authors.
Fuel | Year: 2013

An integrated hot coal gas cleaning process is proposed with emphasis on simultaneous removal of multiple impurities including sulfur containing species, NOx precursors, mercury and tarry materials. Acti-vated- char-supported sorbents were synthesized by gasifying Fe and Mo impregnated Chinese lignite coal in steam (15%, vol) at 1100 K for 15 min. Sulfur removal properties of the sorbent samples were examined by sulfidation experiments using simulated coal gases (with 4700 ppmv H2S and 470 ppmv COS) at a space velocity of 1000 h-1 using a fixed-bed quartz reactor at the temperature range of 673-873 K. The SEM with EDS and XRD were used to examine the physical and chemical changes in the sorbents during sulfidation. The active metal oxides components were dispersed in the char matrix as nanosize particles resulting in a high reactivity of the sorbents towards H2S and COS contained in coal gases. Under the conditions in this study, the sorbents can effectively remove H2S and COS from the simulated coal gases with high efficiency. Sulfur removal is influenced by the level of iron-loading. The presence of Mo along with Fe in the char-supported sorbents can significantly increase the desulfurization efficiency. © 2010 Elsevier Ltd. All rights reserved.


Cheng H.,Taiyuan University of Technology | Zhang S.,BYD Company Ltd | Quan L.,Taiyuan University of Technology
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering | Year: 2015

To increase the power coefficient of blade at both rated and low wind conditions, the distribution of aerodynamic shape parameter at each blade element is studied. The wind turbine is typically operated under low wind conditions, however the influence has rarely been considered in blade optimization model. Hence, a nonlinear constrained optimization model with power coefficient under low wind conditions is introduced based on the blade element momentum theory and Wilson theory. Since the penalty factor is difficult to be determined in penalty function method when dealing with constraints, which may lead to prematurity phenomenon that the algorithm falls into local solution, a hybrid particle swarm algorithm combined with feasible dominated-constraint method is brought up. Based on particle swarm optimization theory and simulated annealing theory, the algorithm applies feasible dominated-constraint method to perform random survival selection under drifting annealing probability, which keeps the population diverse and can be evolving in more optimized direction, thus solves the problem that nonlinear constraint is difficult to handle and the population's tendency to fall into local solution. So as to verify the algorithm, a nonlinear constrained optimization model for the 1.5MW wind turbine blade is established. The results indicate that the method can effectively handle nonlinear constraints, avoid prematurity of the process and increase the power coefficient of blade under rated and low wind conditions. It provides an excellent way of theoretical analysis to handle nonlinear constraints. ©2015 Journal of Mechanical Engineering.


Zuo Z.-J.,Key Laboratory of Coal Science and Technology | Li J.,Key Laboratory of Coal Science and Technology | Han P.-D.,Taiyuan University of Technology | Huang W.,Key Laboratory of Coal Science and Technology
Journal of Physical Chemistry C | Year: 2014

To better understand the autoxidation mechanism of Cu-based catalysts, we studied the oxidation of Cu sheet exposed to ultrahigh vacuum and air at ambient temperature using X-ray photoelectron spectroscopy (XPS) and density functional theory. Six main stages of Cu autoxidation are revealed: (1) dissociative adsorption of O2, (2) coexistence of nondissociative and dissociative H2O adsorption, (3) diffusion of O and OH into Cu bulk, (4) formation of metastable Cu2O layer, (5) further oxidation and formation of metastable Cu(OH)2 and CuO layer, and (6) transformation phase of the metastable Cu(OH)2 to CuO. The formation of Cu(OH)2 depends on the relative humidity of air and the concentration of adsorbed OH of the Cu sheet. On the basis of these results, we propose that the preservation time of the Cu-based catalysts should be decreased or the catalysts should be preserved in a high vacuum and at low relative humidity. Considering the time of the sample preparation before ex situ XPS analysis and other surface characterizations, the Cu-based catalysts need to be etched by ∼10 s using an Ar ion gun. These findings serve as a guide for the preservation and preparation of Cu-based catalysts before actual measurement. © 2014 American Chemical Society.


Zhao B.,Taiyuan University of Technology | Liu J.,Shanxi Polytechnic College
Journal of Computational Information Systems | Year: 2011

The constant modulus algorithm (CMA) is a stochastic gradient adaptive algorithm that results from minimizing a no-quadratic cost function of the equalizer coefficience involving higher order statistics. The variable step-size constant modulus algorithm (CMA) solves the contradiction between convergence speed and convergence precision of the fixed step-size CMA. Among many variable step-size constant modulus algorithms, a common method is using MSE to control the step-size variation. This paper studies the influence of MSE on tracking channel and anti-interference performance of an improved variable step-size constant modulus algorithm. The computer simulation result is in good agreement with theoretical analysis. © 2011 Binary Information Press.


Liu S.-D.,Key Laboratory of Advanced Transducers and Intelligent Control System of Ministry of Education and | Liu S.-D.,Taiyuan University of Technology | Leong E.S.P.,Institute of Materials Research and Engineering of Singapore | Li G.-C.,Hong Kong Polytechnic University | And 5 more authors.
ACS Nano | Year: 2016

Plasmonic oligomers composed of metallic nanoparticles are one class of the most promising platforms for generating Fano resonances with unprecedented optical properties for enhancing various linear and nonlinear optical processes. For efficient generation of second-harmonic emissions at multiple wavelength bands, it is critical to design a plasmonic oligomer concurrently having multiple Fano resonances spectrally matching the fundamental excitation wavelengths and multiple plasmon resonance modes coinciding with the harmonic wavelengths. Thus far, the realization of such a plasmonic oligomer remains a challenge. This study demonstrates both theoretically and experimentally that a plasmonic nonamer consisting of a gold nanocross surrounded by eight nanorods simultaneously sustains multiple polarization-independent Fano resonances in the near-infrared region and several higher-order plasmon resonances in the visible spectrum. Due to coherent amplification of the nonlinear excitation sources by the Fano resonances and efficient scattering-enhanced outcoupling by the higher-order modes, the second-harmonic emission of the nonamer is significantly increased at multiple spectral bands, and their spectral positions and radiation patterns can be flexibly manipulated by easily tuning the length of the surrounding nanorods in the nonamer. These results provide us with important implications for realizing ultrafast multichannel nonlinear optoelectronic devices. © 2016 American Chemical Society.


Kosec G.,Jozef Stefan Institute | Kosec G.,University of Nova Gorica | Sarler B.,University of Nova Gorica | Sarler B.,Slovenian Institute of Metals And Technology | Sarler B.,Taiyuan University of Technology
Engineering Analysis with Boundary Elements | Year: 2014

Simulation of macrosegregation with mesosegregates as a consequence of solidification of a binary Sn-10%Pb alloy in a 2-dimensional rectangular cast is tackled in the present paper. Coupled volume averaged governing equations for mass, energy, momentum and species transfer are considered by incorporating Lever solidification rule and incompressible Newtonian fluid with Darcy limit in the mushy zone. Solid phase is assumed stationary. Double diffusive effects in the melt are modeled by the thermal and solutal Boussinesq hypothesis. The physical model is solved by the meshless Local Radial Basis Function Collocation Method (LRBFCM) by using 5-noded influence domains, multiquadrics radial basis functions and explicit time stepping. Pressure-velocity coupling is based on local pressure correction. Adaptive upwinding has to be used for stabilization of the convective terms. The numerical simulations reveal instabilities during solidification process that introduce anomalies in the final segregation map that scale with the typical cast as well as sub-cast dimensions. The main advantages of choosing the represented meshless approach for solving the problem are in its simplicity and similar coding in 2D and 3D, as well as straightforward applicability in non-uniform node arrangements. The locality of the proposed numerical approach is also convenient for parallel execution. It is demonstrated that LRBFCM can be advantageously used in casting simulations where the chemical segregation exhibits industrially relevant multi-scale patterns. © 2014 Elsevier Ltd.


Su Q.,Taiyuan University of Technology | Dong Z.,Zhejiang Normal University | Zhang J.,Zhejiang Normal University | Du G.,Taiyuan University of Technology | And 2 more authors.
Nanotechnology | Year: 2013

The lithiation reaction of ZnO as an anode in a lithium-ion battery (LIB) is unclear. The electrochemical behavior of ZnO was investigated inside a transmission electron microscope (TEM) by constructing a nano-LIB using an individual ZnO/graphene sheet as the electrode. The lithiation reaction of ZnO/graphene was monitored by simultaneous determination of the structure with high-resolution TEM, electron diffraction pattern and electron energy-loss spectroscopy. Two kinds of reaction modes were revealed in terms of different reaction rates. One was the violent reaction mode, in which one particle can evolve into an aggregate of many nanoparticles within the Li2O matrix in 1-2 min. The other was the peaceful evolution mode, in which each ZnO nanoparticle evolves into a core-shell particle with multi-domains constituted of Zn and LiZn nanograins. Abnormally large Zn nanocrystals grow quickly in the violent reaction mode, which can suppress the formation of LiZn and impair the reversible capacity. Our observations give direct evidence and important insights for the lithiation mechanism of metal oxide anodes in LIBs. © 2013 IOP Publishing Ltd.


Su Q.,Taiyuan University of Technology | Chang L.,Zhejiang Normal University | Zhang J.,Zhejiang Normal University | Du G.,Taiyuan University of Technology | And 2 more authors.
Journal of Physical Chemistry C | Year: 2013

The reaction mechanism of ceria as an anode in a lithium ion battery (LIB) is unknown. To solve this issue, a nano-LIB was constructed inside a transmission electron microscope (TEM) using an individual CeO 2/graphene composite as the anode. The lithiation/delithiation cycles of the CeO2/graphene composite were conducted inside the TEM, and the electrochemical process was in situ monitored by simultaneous determination of the microstructure with high-resolution TEM, electron diffraction, and electron energy loss spectroscopy. The surfaces of the graphene nanosheets and ceria nanoparticles were covered by a nanocrystalline Li2O layer after lithiation, and the Li2O layer shrank and showed partially reversible changes after delithiation. The CeO2 nanoparticles showed imperceptible volumetric and morphological changes, while comprehensive analysis revealed a fully reversible phase transformation between fluorite CeO 2 and cubic Ce2O3 during the electrochemical process. These results give direct evidence and profound insights into the lithiation/delithiation mechanism of CeO2/graphene anode in a LIB. © 2013 American Chemical Society.


Jing L.,Taiyuan University of Technology | Jing L.,National University of Singapore | Wang Z.,Taiyuan University of Technology | Zhao L.,Taiyuan University of Technology
Composite Structures | Year: 2014

The dynamic response of peripherally clamped cylindrical sandwich shells with two aluminum face-sheets and an aluminum foam core has been experimentally investigated using an improved loading technique. The resistance to impact loading is assessed by using the permanent transverse deflection at central point of back face-sheet of the sandwich shell. The comprehensive deformation and failure modes of specimens were classified and analyzed in term of face-sheets and core, and then the failure mode map of specimens was presented. Effects of impulse, face-sheet thickness, core thickness and relative density of core on the resistance to impact loading were discussed in detail. Deformation mechanism of sandwich shells subjected to projectile impact was explored based on the results of strain gauges adhered on the face-sheets. Results indicate that both the deformation/failure modes and back face-sheet deflection of sandwich shells are sensitive to impulse and their geometrical configurations, and the curved sandwich structures have an evident advantage on the resistance to deform, to the flatted sandwich panels. The experimental results have important reference value to the further study and engineering application of metallic sandwich structures. © 2013.


Jing L.,Taiyuan University of Technology | Jing L.,National University of Singapore | Wang Z.,Taiyuan University of Technology | Zhao L.,Taiyuan University of Technology
Composites Part B: Engineering | Year: 2014

A simplified theoretical analysis is developed to predict the dynamic response of clamped cylindrical sandwich shells with aluminum foam cores under air blast loading. In this analytical solution, the whole response of the sandwich shell is split into three sequential stages, similar with the existing three-stage theoretical framework of sandwich structures. In the first stage the blast impulse is assumed to only transfer to the velocity of the front face-sheet. The metallic foam core is considered approximately to be a progressive compressive mode in the second stage, while the back face-sheet is still stationary. In the final stage, the classical monolithic shell theory based on an energy dissipation rate balance approach is employed; and the "upper" and "lower" bounds of the maximum back face-sheet central point deflections and response time are obtained by incorporating a comprehensive circumscribing and inscribing yield loci. A reasonable agreement between the theoretical predictions and experimental results is found for the maximum back face-sheet central point deflection of sandwich shells. The proposed theoretical consideration is significant to guide the engineering applications of cellular metal sandwich structures subjected to air blast loading. © 2013 Elsevier Ltd. All rights reserved.


Zhong C.,Ningbo University | Yue X.,Shanghai University | Zhang Z.,Taiyuan University of Technology | Lei J.,Shanghai University of Electric Power
Pattern Recognition | Year: 2015

Abstract The aim of clustering ensemble is to combine multiple base partitions into a robust, stable and accurate partition. One of the key problems of clustering ensemble is how to exploit the cluster structure information in each base partition. Evidence accumulation is an effective framework which can convert the base partitions into a co-association matrix. This matrix describes the frequency of a pair of points partitioned into the same cluster, but ignores some hidden information in the base partitions. In this paper, we reveal some of those information by refining the co-association matrix from data point and base cluster level. From the data point level, as pairs of points in the same base cluster may have varied similarities, their contributions to the co-association matrix can be different. From the cluster level, since the base clusters may have diversified qualities, the contribution of a base cluster as a whole can also be different from those of others. After being refined, the co-association matrix is transformed into a path-based similarity matrix so that more global information of the cluster structure is incorporated into the matrix. Finally, spectral clustering is applied to the matrix to generate the final clustering result. Experimental results on 8 synthetic and 8 real data sets demonstrate that the clustering ensemble based on the refined co-association matrix outperforms some state-of-the-art clustering ensemble schemes. © 2015 Elsevier Ltd. All rights reserved.


Deng J.,Taiyuan University of Technology | Kang L.,Taiyuan University of Technology | Bai G.,China Institute of Technology | Li Y.,Taiyuan University of Technology | And 6 more authors.
Electrochimica Acta | Year: 2014

Co3O4 and Co3O4/CoO nanoparticles have been synthesized by a one-step solution combustion process by adjusting the molar ratio of citric acid (fuel) and Co(NO3) 2·6H2O (oxidizer). The effects of citric acid/Co(NO3)2·6H2O molar ratios on phase composition and morphology of products were investigated by XRD and SEM. With the increase of the fuel dosage, the products transformed from granular aggregates of cubic Co3O4 into a mixture of cubic Co 3O4 and tetragonal CoO with fluffy sheet morphologies. Electrochemical measurements indicated that the products (Co3O 4) showed a capacitance up to 179.7 F·g-1 (at 0.2 A·g-1) when the citric acid/Co(NO3) 2·6H2O molar ratio was 7/27. Significantly, the capacitance could be further improved by 102% (362.8 F·g-1 at 0.2 A·g-1) after annealing at 350 °C for 3 h under nitrogen atmosphere. This annealed sample also demonstrated decent rate performance (285.7 F·g-1 at 4 A·g-1) and cycling stability (73.5% retention after 1000 cycles). The current study suggests that this process has promise in large-scale production of electrode materials for supercapacitors. © 2014 Elsevier Ltd.


Yuan W.,Zhejiang Normal University | Zhang J.,Zhejiang Normal University | Xie D.,Zhejiang Normal University | Dong Z.,Zhejiang Normal University | And 3 more authors.
Electrochimica Acta | Year: 2013

Uniform, hierarchical and porous CoO/C polyhedra were synthesized by impregnating hydrothermally fabricated Co3O4 polyhedra with sugar solution followed by calcination in inert atmosphere. Each CoO/C polyhedron was built up of numerous ordered nanoparticles (around 100 nm). As anode material for Li-ion batteries, the CoO/C polyhedra exhibited an initial discharge capacity of 1025 mAh g-1, and remained a reversible capacity of 510mAhg-1 after 50 cycles at a current density of 100mAg-1. High Coulombic efficiency over 99% and improved rate capability were achieved for the CoO/C polyhedra. Hierarchical structure and high porosity was benefit to the infiltration of electrolyte and tolerant volume expansion, and hence was responsible for the good electrochemical performance. © 2013 Elsevier Ltd. All rights reserved.


Guan G.,Hirosaki University | Chen G.,Hirosaki University | Kasai Y.,Industrial Research Institute | Lim E.W.C.,National University of Singapore | And 5 more authors.
Applied Catalysis B: Environmental | Year: 2012

Calcined scallop shell (CS) exhibits alkaline property with a porous structure, and could be applied for the adsorption and decomposition of biomass-derived tar. In this study, steam reforming of tar derived from pruned apple branch over CS was investigated in a fixed bed at 650°C. It was found that CS had good activity for the steam reforming of tar to produce synthesis gas (syngas), and was able to be recycled. To promote the gas production efficiency, iron or nickel was supported on the CS, and used for the reforming of tar. The effect of heating rate on the gas production rate was investigated, and it was found that reduced iron- or nickel-supported CS showed better activities under the condition of rapid heating. Iron- or nickel-based catalyst in its oxide state was also investigated for the reforming of tar. No catalytic activity was found at the beginning, but good activity appeared after approximately 30min of reaction when the metal oxide was reduced to its metallic form by the initially generated syngas (CO and H 2) from the pyrolysis of biomass without the aid of catalyst. Iron and nickel in their metallic forms rather than their oxide ones were considered as active sites for the reforming of tar. Furthermore, the alkaline elements in the biomass, which could enhance the activity of the catalysts, were identified to be accumulated on the surface of the catalysts with the biomass-derived tar. As a result, a larger amount of syngas was produced when the regenerated catalysts were applied. Based on these experimental results, a possible catalytic process was proposed. © 2011 Elsevier B.V..


Xue H.-B.,Taiyuan University of Technology | Nie Y.-H.,Shanxi University | Chen J.,Shanghai University | Ren W.,Shanghai University
Annals of Physics | Year: 2015

We study theoretically the full counting statistics of electron transport through a quantum dot weakly coupled to two ferromagnetic leads, in which an effective nuclear-spin magnetic field originating from the configuration of nuclear spins is considered. We demonstrate that the quantum coherence between the two singly-occupied eigenstates and the spin polarization of two ferromagnetic leads play an important role in the formation of super-Poissonian noise. In particular, the orientation and magnitude of the effective field have a significant influence on the variations of the values of high-order cumulants, and the variations of the skewness and kurtosis values are more sensitive to the orientation and magnitude of the effective field than the shot noise. Thus, the high-order cumulants of transport current can be used to qualitatively extract information on the orientation and magnitude of the effective nuclear-spin magnetic field in a single quantum dot. © 2015 Elsevier Inc.


Sun S.,Peking University | Niu Y.,Peking University | Niu Y.,Taiyuan University of Technology | Sun Z.,Peking University | And 2 more authors.
RSC Advances | Year: 2015

Solubilities of SO2 in ethylene glycol derivatives were determined by dynamic isothermal gas-liquid equilibrium (GLE) experiments, and the thermodynamic parameters of the absorption processes were calculated. The GLE results indicated that the solubilities of SO2 in ethylene glycol derivatives increase in the order: diols < monomethyl ethers < dimethyl ethers, with the enthalpy values ranging from -23.2 to -43.3 kJ mol-1. The regeneration experiment found that the absorption of SO2 in tetraethylene glycol dimethyl ether is reversible, and the solvents can be reused without a significant loss of absorption capacity. The interactions between SO2 and ethylene glycol derivatives were investigated by UV, IR and NMR. In addition, a 1H-NMR spectroscopy technique with external references was used to investigate the physical absorption process of SO2 for the first time, in order to avoid the influence of deuterated solvents. Spectroscopic investigations showed that the interactions between SO2 and ethylene glycol derivatives are based on both the charge-transfer interaction and hydrogen bond. Ethylene glycol derivatives with desirable absorption capacities and excellent regeneration abilities are promising alternatives to conventional sorbents in SO2 separation. © The Royal Society of Chemistry 2015.


Xie D.,Zhejiang Normal University | Chang L.,Zhejiang Normal University | Wang F.,Zhejiang Normal University | Du G.,Zhejiang Normal University | Xu B.,Taiyuan University of Technology
Journal of Alloys and Compounds | Year: 2012

We report a facile, surfactant-free method for synthesizing double pyramid-like ZnO architectures via an ultrasound-assisted route. The morphology, microstructures, and porosity of the materials have been studied and the formation mechanism has been discussed. Uniform octahedral ZnC 2O 4 precursors were first formed during ultrasound irradiation, and then transformed to macro-/mesoporous ZnO with the preservation of original shape after calcination at 350 °C. The obtained hierarchical ZnO double-pyramids were composed of ZnO nanoparticles of ∼35 nm and pores with the main distribution between 20 and 100 nm. Raman and photoluminescence measurements reveal the presence of intrinsic defects in the porous ZnO, which accounts for the narrowed band gap (3.16 eV) and the sharp blue emission at 472 nm. Moreover, the ZnO product possesses large specific surface area and exhibits extraordinary photocatalytic activity to degrade organic pollutants. © 2012 Elsevier B.V. All rights reserved.


Su Q.,Zhejiang Normal University | Su Q.,Taiyuan University of Technology | Xie D.,Zhejiang Normal University | Zhang J.,Zhejiang Normal University | And 2 more authors.
ACS Nano | Year: 2013

Transition metal oxides have attracted tremendous attention as anode materials for lithium ion batteries (LIBs) recently. However, their electrochemical processes and fundamental mechanisms remain unclear. Here we report the direct observation of the dynamic behaviors and the conversion mechanism of Fe2O3/graphene in LIBs by in situ transmission electron microscopy (TEM). Upon lithiation, the Fe 2O3 nanoparticles showed obvious volume expansion and morphological changes, and the surfaces of the electrode were covered by a nanocrystalline Li2O layer. Single-crystalline Fe2O 3 nanoparticles were found to transform to multicrystalline nanoparticles consisting of many Fe nanograins embedded in Li2O matrix. Surprisingly, the delithiated product was not Fe2O 3 but FeO, accounting for the irreversible electrochemical process and the large capacity fading of the anode material in the first cycle. The charge-discharge processes of Fe2O3 in LIBs are different from previously recognized mechanism, and are found to be a fully reversible electrochemical phase conversion between Fe and FeO nanograins accompanying the formation and disappearance of the Li2O layer. The macroscopic electrochemical performance of Fe2O3/graphene was further correlated with the microcosmic in situ TEM results. © 2013 American Chemical Society.


Ma J.,Taiyuan University of Technology | Ma J.,University of Texas at Dallas | Loizou P.C.,University of Texas at Dallas
Speech Communication | Year: 2011

Most of the existing intelligibility measures do not account for the distortions present in processed speech, such as those introduced by speech-enhancement algorithms. In the present study, we propose three new objective measures that can be used for prediction of intelligibility of processed (e.g.; via an enhancement algorithm) speech in noisy conditions. All three measures use a critical-band spectral representation of the clean and noise-suppressed signals and are based on the measurement of the SNR loss incurred in each critical band after the corrupted signal goes through a speech enhancement algorithm. The proposed measures are flexible in that they can provide different weights to the two types of spectral distortions introduced by enhancement algorithms, namely spectral attenuation and spectral amplification distortions. The proposed measures were evaluated with intelligibility scores obtained by normal-hearing listeners in 72 noisy conditions involving noise-suppressed speech (consonants and sentences) corrupted by four different maskers (car, babble, train and street interferences). Highest correlation (r = -0.85) with sentence recognition scores was obtained using a variant of the SNR loss measure that only included vowel/consonant transitions and weak consonant information. High correlation was maintained for all noise types, with a maximum correlation (r = -0.88) achieved in street noise conditions. © 2010 Elsevier B.V. All rights reserved.


Cao Y.,Zhejiang Normal University | Su Q.,Zhejiang Normal University | Che R.,Fudan University | Du G.,Zhejiang Normal University | And 2 more authors.
Synthetic Metals | Year: 2012

We present the first report concerning the one-step synthesis of Ni/graphene nanocomposites via a substrate-free, atmospheric-pressure chemical vapor deposition process. The as-grown thin graphene sheets are produced in large scale with the thickness of ∼2 nm, and they are decorated with numerous Ni/graphene core-shell nanoparticles. The nucleation and growth mechanism of the composite has been proposed based on careful transmission electron microscopy analysis. Ni 3C domains within Ni nanoparticles have been observed, indicating a transformation between nickel and nickel carbide during graphene growth owing to the diffuse and precipitation of carbon atoms. Moreover, such Ni/graphene nanocomposites exhibit excellent microwave absorption and electrochemical ethanol sensing properties. This study opens up a new synthesis route for graphene-based materials. © 2012 Elsevier B.V. All rights reserved.


Xie D.,Zhejiang Normal University | Su Q.,Taiyuan University of Technology | Dong Z.,Zhejiang Normal University | Zhang J.,Zhejiang Normal University | Du G.,Zhejiang Normal University
CrystEngComm | Year: 2013

Porous NiO hollow microspheres have been synthesized via a simple hydrothermal process using l-cysteine as a structure-directing agent followed by calcination. The as-synthesized NiO microspheres are hollow with diameters of 2-3 μm. The shells of the microspheres are built from nanoparticles with diameters of 30-50 nm, and the interior cavities are around 0.75 μm in diameter. A plausible mechanism has been proposed to explain the formation of the porous NiO hollow spheres. When evaluated as anode materials for lithium ion batteries, the porous NiO hollow microspheres show outstanding electrochemical performances, including high reversible capacity of 847.2 mAh g-1 after 50 cycles at 100 mA g-1, high rate capability with a discharge capacity of 470 mAh g-1 at a current density of 800 mA g -1, and good cycling stability. The excellent lithium-storage performance can be attributed to the porous hollow architectures, which provide fast ion/electron transfer and the structural flexibility for volume change during the cycling process. © 2013 The Royal Society of Chemistry.


Shen J.,Swinburne University of Technology | Lu G.,Nanyang Technological University | Wang Z.,Taiyuan University of Technology | Zhao L.,Taiyuan University of Technology
International Journal of Impact Engineering | Year: 2010

In this paper curved sandwich panels with two aluminium face sheets and an aluminium foam core under air blast loadings were investigated experimentally. Specimens with two values of radius of curvature and different core/face sheet configurations were tested for three blast intensities. All the four edges of the panels were fully clamped. The experiments were carried out by a four-cable ballistic pendulum with corresponding sensors. Impulse acting on the front face of the assembly, deflection history at the centre of back face sheet, and strain history at some characteristic points on the back face were obtained. Then the deformation/failure modes of specimens were classified and analysed systematically. The experimental data show that the initial curvature of a curved sandwich panel may change the deformation/collapse mode with an extended range for bending dominated deformation, which suggests that the performance of the sandwich shell structures may exceed that of both their equivalent solid counterpart and a flat sandwich plate. © 2010 Elsevier Ltd. All rights reserved.


Weiming C.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Shangmin Z.,Xinjiang Institute of Ecology and Geography | Shangmin Z.,Taiyuan University of Technology | Shangmin Z.,University of Chinese Academy of Sciences | And 2 more authors.
Permafrost and Periglacial Processes | Year: 2012

Decadal changes in permafrost distribution on the Qinghai-Tibet Plateau (QTP) over the past 50years (1960-2009) were simulated with a response model that uses data from a digital elevation model, mean annual air temperature (MAAT) and the vertical lapse rate of temperature. Compared with published maps of permafrost distribution, the accuracy of the simulated results is about 85 per cent. The simulation results show: (1) with the continuously rising MAAT over the past 50years, the simulated areas of permafrost on the QTP have continuously decreased; (2) through areal statistics, the simulated areas of permafrost were 1.60×106km2, 1.49×106km2, 1.45×106km2, 1.36×106km2 and 1.27×106km2, respectively, in the 1960s, 1970s, 1980s, 1990s and 2000s; and (3) the rate of permafrost loss has accelerated since the 1980s, and the total area of degraded permafrost is about 3.3×105km2, which accounts for about one-fifth of the total area of permafrost in the 1960s. © 2012 John Wiley & Sons, Ltd.


Guan G.,Hirosaki University | Kaewpanha M.,Hirosaki University | Hao X.,Taiyuan University of Technology | Wang Z.,Taiyuan University of Technology | And 3 more authors.
Fuel | Year: 2013

(Graph Presented) Decomposition of tar derived from 4 biomass resources, i.e., cellulose, lignin (alkaline and dealkaline), pruned apple branch (PAB) and rice straw over calcined scallop shell (CS) and iron (Fe)-loaded CS were performed in a fixed bed reactor at different temperatures. It was found that alkali species such as potassium in the biomass could migrate to the surface of catalyst with the tar, and hence promote catalytic activity ofthe regenerated catalyst. In order to reveal this phenomenon, in this study a small amount of K was doped on CS and Fe-loaded CS and applied in the steam reforming of tar derived from cellulose and dealkaline lignin. The results indicated that the addition of K greatly enhanced hydrogen production rate. © 2012 Elsevier Ltd. All rights reserved.


Su Q.,Zhejiang Normal University | Li J.,Zhejiang Normal University | Du G.,Zhejiang Normal University | Du G.,Taiyuan University of Technology | Xu B.,Taiyuan University of Technology
Journal of Physical Chemistry C | Year: 2012

The electrical and electron field-emission characteristics of individual Fe 3C-filled CNTs were investigated using a scanning tunneling microscope inside a transmission electron microscope. Larger bias sweeping across a CNT can bring about the melting, resolidifying, and decomposition of the encapsulated Fe 3C, which causes structural damage to the CNT. However, the resistance of the CNT reduces significantly after large bias sweep because the graphitization of CNT walls improves and the contact resistance reduces. To get more insights into the mechanism, the microstructure evolution of Fe 3C and the reaction between Fe 3C and CNT during near-equilibrium reaction processes were studied. It was found that thin graphenes form when the Fe 3C fillers decompose by joule heating, which may open up a new route for the graphene fabrication. The field-emission behavior of a single Fe 3C-filled CNT was analyzed based on Fowler-Nordheim theory, which suggested only 8.4% of the hemispherical cap is responsible for the electron emission. © 2012 American Chemical Society.


Sheng Y.,Australian National University | Kong Q.,Shanghai University | Wang W.,Taiyuan University of Technology | Kalinowski K.,Australian National University | Krolikowski W.,Australian National University
Journal of Physics B: Atomic, Molecular and Optical Physics | Year: 2012

We theoretically study the second-harmonic generation via nonlinear Raman-Nath diffraction in an optical medium with the spatial modulation of quadratic nonlinearity. We derive analytical equations that govern the emission properties of this nonlinear wave phenomenon. We also discuss how a substantial range of parameters such as the thickness of a nonlinear medium and the condition of a pump laser affect the strength of the emitted harmonic signals. © 2012 IOP Publishing Ltd.


Fu T.,Taiyuan University of Technology | Li Z.,Tianjin University of Technology
Chemical Engineering Science | Year: 2015

Diminishing petroleum reserves, sharp fluctuations of crude oil prices, increasingly stringent environmental regulations and the global demand for a decreased dependence on petroleum for the production of fuels and chemicals, are the main driving force for the recent renewed interest in Fischer-Tropsch (FT) synthesis in academia and industry. Cobalt catalyst is the preferred catalyst for the production of long-chain paraffins because of its high activity, low water-gas shift activity and comparatively low price. Carbon materials including traditional activated carbons, carbon nanotubes and nanofibres, carbon spheres and mesoporous carbons have been used as the support for cobalt catalyst in the past 10 years for its inert property. The microstructures (e.g., carbon porosity, cobalt particle size, cobalt location and cobalt dispersion) of these carbon supported cobalt catalyst determine the CO conversion and product selectivity. In this paper, we focus on the most recent developments around carbon support structure effect, cobalt intrinsic properties and promoter effect on carbon supported cobalt catalyst for FT synthesis. The nitrogen doping effect, confinement effect and cobalt particle size effect on carbon nanotubes supported Co catalysts are further presented in this review. © 2015 Elsevier Ltd. All rights reserved.


Cui X.,Tsinghua University | Zhao L.,Swinburne University of Technology | Zhao L.,Taiyuan University of Technology | Wang Z.,Swinburne University of Technology | And 4 more authors.
International Journal of Impact Engineering | Year: 2012

The dynamic response of metallic lattice sandwich plates under impulsive loading is studied by experimental investigation. The sandwich structures composed of two identical face sheets and tetrahedral lattice cores, were designed and fabricated through perforated metal sheet forming and welding technology. The air blast experiment of lattice sandwich structures was performed by use of a four-cable ballistic pendulum system. The deformation/failure mechanisms were investigated through experimental observation and analysis. The impulsive resistance of the tetrahedral lattice sandwich structures is quantified by the maximum permanent transverse deflection of the back face sheet as a function of transmitted impulse. The maximum transverse deflections of tetrahedral lattice sandwich plates are compared with that of hexagonal honeycomb ones with identical parent materials and core relative density. The comparison implies that the tetrahedral lattice sandwich structures possess a better impulsive resistance. © 2011 Elsevier Ltd. All rights reserved.


Zhu F.,Swinburne University of Technology | Wang Z.,Swinburne University of Technology | Wang Z.,Taiyuan University of Technology | Lu G.,Swinburne University of Technology | And 2 more authors.
International Journal of Impact Engineering | Year: 2010

A theoretical solution is obtained to predict the dynamic response of peripherally clamped square metallic sandwich panels with either honeycomb core or aluminium foam core under blast loading. In the theoretical analysis, the deformation of sandwich structures is separated into three phases, corresponding to the transfer of impulse to the front face velocity, core crushing and overall structural bending/stretching, respectively. The cellular core is assumed to have a progressive crushing deformation mode in the out-of-plane direction, with a dynamically enhanced plateau stress (for honeycombs). The in-plane strength of the cellular core is assumed unaffected by the out-of-plane compression. By adopting an energy dissipation rate balance approach developed by earlier researchers for monolithic square plates, but incorporating a newly developed yield condition for the sandwich panels in terms of bending moment and membrane force, "upper" and "lower" bounds are obtained for the maximum permanent deflections and response time. Finally, comparative studies are carried out to investigate: (1) influence of the change in the in-plane strength of the core after the out-of-plane compression; (2) performances of a square monolith panel and a square sandwich panel with the same mass per unit area; and (3) analytical models of sandwich beams and circular and square sandwich plates. © 2009 Elsevier Ltd. All rights reserved.


Meng Q.S.,Taiyuan University of Technology | Fan W.H.,Taiyuan University of Technology | Chen R.X.,Taiyuan University of Technology | Munir Z.A.,University of California at Davis
Journal of Alloys and Compounds | Year: 2011

Sc- and Y-doped-Mg2Si samples were reactively sintered by the field-activated and pressure-assisted synthesis (FAPAS) method. The incorporation of these rare-earth elements in this silicide resulted in an n-type semiconductor. The addition of Sc and Y had no discernable effect on the lattice constant of Mg2Si. The average grain size of the Y-doped Mg2Si was about 2 μm, which was smaller than that of the sintered pure Mg2Si. The power factor of samples doped with 2500 ppm Sc was consistently higher than that of pure Mg2Si in the temperature range of 300-550 K. Similarly, the power factor of 2000 ppm Y doped Mg2Si samples was higher than that of pure Mg2Si over the temperature range of 300-675 K; the highest value being about 2.2 × 10-3 W m-1 k-2 at 468 K. This value is about two times that of the undoped Mg2Si at the same temperature. The thermal conductivity of Mg2Si doped with 2000 ppm Y was 80% of that of pure Mg 2Si. The highest figure of merit (ZT) for the Y doped (2000 ppm) samples was 0.23 at 600 K which was higher by a factor of 1.6 than the corresponding value of pure Mg2Si at the same temperature. The results demonstrate the benefits of doping of Mg2Si with Sc and Y in enhancing its thermoelectric properties. © 2011 Elsevier B.V. All rights reserved.


Qiao J.W.,University of Science and Technology Beijing | Qiao J.W.,Taiyuan University of Technology | Sun A.C.,Yuan Ze University | Huang E.W.,National Central University | And 3 more authors.
Acta Materialia | Year: 2011

A Ti-based bulk metallic glass matrix composite (BMGMC) with a homogeneous distribution of dendrites and the composition of Ti46Zr 20V12Cu5Be17 is characterized by a high tensile strength of ∼1640 MPa and a large tensile strain of ∼15.5% at room temperature. The present BMGMC exhibits the largest tensile ductility and highest fracture absorption energy under the stress-strain curve of all dendrite-reinforced BMGMCs developed to date. Tensile deformation micromechanisms are explored through experimental visualization and theoretical analyses. After tension, fragmentation of the dendrites, rather than crystallization within the glass matrix and/or atom debonding near the interface of dual-phase composites, is responsible for the high tensile ductility. The subdivisions within the interior of dendrites are separated by shear bands and dense dislocation walls, and local separation of dendrites under modes I and II prevails. The multiplication of dislocations, severe lattice distortions, and even local amorphization dominate within the dendrites. Good structural coherency of the interface is demonstrated, despite being subjected to significant plastic deformation. Theoretical analyses reveal that the constitutive relations elastic-elastic, elastic-plastic, and plastic-plastic of dual-phase BMGMC generally correspond to the (1) elastic, (2) work-hardening, and (3) softening deformation stages, respectively. The capacity for work-hardening is highly dependent on the large plastic deformation of the dendrites and the high yield strength of the glass matrix. The present study provides a fundamental basis for designing work-hardening dual-phase BMGMCs exhibiting remarkably homogeneous deformation. © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.


Loizou P.C.,University of Texas at Dallas | Ma J.,Taiyuan University of Technology
Journal of the Acoustical Society of America | Year: 2011

The conventional articulation index (AI) measure cannot be applied in situations where non-linear operations are involved and additive noise is present. This is because the definitions of the target and masker signals become vague following non-linear processing, as both the target and masker signals are affected. The aim of the present work is to modify the basic form of the AI measure to account for non-linear processing. This was done using a new definition of the output or effective SNR obtained following non-linear processing. The proposed output SNR definition for a specific band was designed to handle cases where the non-linear processing affects predominantly the target signal rather than the masker signal. The proposed measure also takes into consideration the fact that the input SNR in a specific band cannot be improved following any form of non-linear processing. Overall, the proposed measure quantifies the proportion of input band SNR preserved or transmitted in each band after non-linear processing. High correlation (r 0.9) was obtained with the proposed measure when evaluated with intelligibility scores obtained by normal-hearing listeners in 72 noisy conditions involving noise-suppressed speech corrupted in four different real-world maskers. © 2011 Acoustical Society of America.


Ban H.,University Of Science And Technology Liaoning | Li C.,Taiyuan University of Technology | Li C.,Tokyo Gas Co. | Asami K.,University of Kitakyushu | Fujimoto K.,Tokyo Gas Co.
Catalysis Communications | Year: 2014

A series of Cu/Zn/Zr (CZZ) catalysts with different rare earth elements (La, Ce, Nd and Pr) were prepared by co-precipitation method and tested for CO2 hydrogenation to methanol. The influence of modifier (La, Ce, Nd and Pr) on the physicochemical properties of CZZ catalysts was studied. The results of catalytic test reveal that CO2 conversion was correlated to the introduction of different promoters. The introduction of La and Ce favors the production of methanol, and Nd and Pr modified CZZ catalysts show relative low activity compared with the reference CZZ catalyst. © 2014 The Authors. Published by Elsevier B.V.


Chen X.-B.,Beijing University of Posts and Telecommunications | Xu G.,Taiyuan University of Technology | Niu X.-X.,Beijing University of Posts and Telecommunications | Wen Q.-Y.,Beijing University of Posts and Telecommunications | Yang Y.-X.,Beijing University of Posts and Telecommunications
Optics Communications | Year: 2010

The central theme of this paper is that we propose an efficient protocol for comparing the equal information with the help of a third party (TP). We assume that TP is semi-honest, i.e., TP executes the protocol loyally, keeps a record of all its intermediate computations and might try to steal the players' private inputs from the record, but he cannot be corrupted by the adversary. The security of this protocol with respect to various kinds of attacks is discussed. Our protocol utilizes the triplet entangled states and the simple single-particle measurement. The particles carried the secret messages do not be repeatedly transmitted. The players' messages are divided into many groups. Sometimes, the protocol is already successfully completed, but all data are not compared. Thus, many time and huge quantum resources can be saved. © 2009 Elsevier B.V. All rights reserved.


Chen X.-B.,Beijing University of Posts and Telecommunications | Xu G.,Taiyuan University of Technology | Yang Y.-X.,Beijing University of Posts and Telecommunications | Wen Q.-Y.,Beijing University of Posts and Telecommunications
Optics Communications | Year: 2010

Through designing a quantum communication network, we propose a protocol for the teleportation between multiple senders and multiple receivers via only one controller. In order to rationally employ the quantum entanglement resources, the controller shares the entangled state with every sender, while there is no directly shared entanglement link between sender and receiver. The security is analyzed in detail. Moreover, this protocol reduces the classical communication cost in the public channel by means of the coding. © 2010 Elsevier B.V. All rights reserved.


Yuan H.-P.,Shanghai JiaoTong University | Cheng X.-B.,Shanghai Municipal Drainage Operation Ltd. | Chen S.-P.,Shanghai Environmental Sanitation Engineering Design Institute | Zhu N.-W.,Shanghai JiaoTong University | Zhou Z.-Y.,Taiyuan University of Technology
Bioresource Technology | Year: 2011

The enhancements of electrolysis-pretreated conditioning were investigated in this study. Normalized capillary suction time (CST) was used to evaluate sludge dewaterability. Extracellular polymeric substance (EPS) concentration, viscosity and scanning electron microscopy (SEM) were determined to explain the observed changes in conditioning process. It indicated that pretreatment at 50v and 5min with Ti/RuO2 anode was determined to be the optimal condition, which generated the lowest normalized CST and optimal soluble EPS concentration, leading to the decreasing of viscosity. EPS had positive correlation with the normalized CST. Subjecting to a combination of electrolysis pretreatment and flocculants conditioning, 50% dosage of cationic polyacrylamide (PAM) could be reduced. When co-conditioned with electrolysis and polymerization ferric sulfate (PFS), it did not present any clear advantages over PFS conditioning alone. Furthermore, SEM investigation indicated that electrolysis pretreatment could rupture sludge, release the interstitial water and extracellular substances, especially protein and polysaccharide, and consequently enhance its dewaterability. © 2011 Elsevier Ltd.


Zhu Z.,Beijing Materials University | Zhang D.,Taiyuan University of Technology | Yan H.,Beijing Materials University | Li W.,University of Science and Technology Beijing | Qilu,Beijing Materials University
Journal of Materials Chemistry A | Year: 2013

This work developed a novel ammonium oxalate-carbonate composite co-precipitation method to prepare spinel LiNi0.5Mn 1.5O4. By this method combined with a facile hydrothermal treatment and particular cooling process, an ideal spinel with precise stoichiometric Ni/Mn and classic Fd3m structure is obtained, and furthermore, the Mn3+ content can be strictly limited. Additionally, the prepared LiNi0.5Mn1.5O4 has a spherical hierarchical morphology, composed of nano or submicron primary particles. This LiNi 0.5Mn1.5O4 shows superlative electrochemical performance. It delivers a discharge capacity of 141.2 mA h g-1, and importantly 98.2% of which discharges at 4.7 V. After 200 cycles at 0.3 C, 1 C and 3 C, the capacity retentions are 96.3%, 94.4% and 91.1%, respectively. Chemical and electrochemical measurements indicate that the elimination of the majority of Mn3+ in the obtained LiNi0.5Mn 1.5O4 results in the high capacity proportion at 4.7 V. Additionally, the retained Fd3m structure and spherical hierarchical morphology also effectively favour the cycling and rate performances. This journal is © 2013 The Royal Society of Chemistry.


Ren L.,Shanxi Institute of Coal CAS Chemistry | Ren L.,University of Chinese Academy of Sciences | Yang J.,Shanxi Institute of Coal CAS Chemistry | Gao F.,Taiyuan University of Technology | Yan J.,Basic Research Service
Energy and Fuels | Year: 2013

The gasification reactivity of 13 carbonaceous materials in CO2 or in steam was studied in the temperature range 1000-1600 C. The gasification reaction was carried out in a drop-in-fixed-bed reactor under atmospheric pressure. The gasifying agent fed into the reactor either as pure gas or as 36% volumetric concentration in argon with a total gas flow rate of 500 mL/min. The test samples included different rank coals, petcokes, and graphites. The raw materials were used to eliminate the problem related to char prepreparation. The dynamic profiles of gasification rate were used to compare the gasification behaviors for different samples. The physicochemical characteristics of chars were evaluated by scanning electron microscopy and N2 adsorption method. The experimental results reveal that the difference in gasification reactivity among samples decreases as the temperature increases and is not distinguishable for most coals at 1600 C. However, the temperature is still critical for gasification of petcokes and some high-rank coals at high temperature. The gasification reactivity of petcokes is 2-9 times lower than that of coals at 1600 C. The kinetic analysis reveals that the temperature dependence of reactivity varies with the type of materials. It is interested to find that, in the temperature range 1400-1600 C, the gasification reactivity in CO2 is higher than that in steam for coals but not for petcokes. From the views of the reaction thermodynamics, the gas diffusion difficulty, and the catalytic effect, the high temperature is favorable to the CO 2-gasification. The effect of AAEMs (alkali and alkaline earth metals) should be a key factor. The content of AAEMs is apparent in coals but limited in petcokes. The Arrhenius plots reveal that the gasification mechanism may be altered around 1200 C for most of coals. The petcokes are appeared with the most compact physical structure and the least gasification reactivity. Either the shrinking core model (SCM) or the volume reaction model (VRM) is suitable for most of the samples and conditions but not suitable for the petcokes. A diffusion term associated with the carbon structure may be needed for modelling the gasification behaviors of the petcoke-like materials. © 2013 American Chemical Society.


Guo R.,Beijing University of Posts and Telecommunications | Guo R.,Taiyuan University of Technology | Tian B.,Beijing University of Posts and Telecommunications | Wang L.,Beihang University
Nonlinear Dynamics | Year: 2012

Under investigation in this paper is the reduced Maxwell-Bloch system, which describes the propagation of the intense ultra-short optical pulses through a two-level dielectric medium. Through symbolic computation, conservation laws are derived and N-fold Darboux transformation (DT) is constructed for that system. By virtue of the DT obtained, multisoliton solutions are generated. Figures are plotted to reveal the following dynamic features of the solitons: (1) Elastic interactions between two bright one-peak solitons, between two bight two-peak solitons and between two dark two-peak solitons; (2) Parallel propagations between two bright one-peak solitons, between two bright two-peak solitons and between two dark two-peak solitons; (3) Periodic propagations of hump solitons, of a pair of bound hump solitons with the same amplitude and of dark solitons. © Springer Science+Business Media B.V. 2012.


Cui Y.,Zhejiang University | Cui Y.,University of Illinois at Urbana - Champaign | Cui Y.,Taiyuan University of Technology | Fung K.H.,University of Illinois at Urbana - Champaign | And 8 more authors.
Nano Letters | Year: 2012

We present an ultrabroadband thin-film infrared absorber made of sawtoothed anisotropic metamaterial. Absorptivity of higher than 95% at normal incidence is supported in a wide range of frequencies, where the full absorption width at half-maximum is about 86%. Such property is retained well at a very wide range of incident angles too. Light of shorter wavelengths are harvested at upper parts of the sawteeth of smaller widths, while light of longer wavelengths are trapped at lower parts of larger tooth widths. This phenomenon is explained by the slowlight modes in anisotropic metamaterial waveguide. Our study can be applied in the field of designing photovoltaic devices and thermal emitters. © 2012 American Chemical Society.


Zhang W.,Taiyuan University of Technology | Yin R.,Taiyuan University of Technology | Wang Y.,CAS Institute of Physics
Physical Review B - Condensed Matter and Materials Physics | Year: 2013

We systematically study an extended Bose-Hubbard model with atom hopping and atom-pair hopping in the presence of a three-body constraint on the triangular lattice. By means of large-scale quantum Monte Carlo simulations, the ground-state phase diagram is studied. We find a first-order transition between the atomic superfluid phase and the pair superfluid phase when the ratio of the atomic hopping and the atom-pair hopping is adapted. The first-order transition remains unchanged under various conditions. We then focus on the interplay among the atom-pair hopping, the on-site repulsion, and the nearest-neighbor repulsion. With on-site repulsion present, we observe first-order transitions between the Mott insulators and pair superfluid driven by the pair hopping. With the nearest-neighbor repulsion turning on, three typical solid phases with 2/3, 1, and 4/3 filling emerge at small atom-pair hopping region. A stable pair supersolid phase is found at small on-site repulsion. This is due to the three-body constraint and the pair hopping, which essentially make the model a quasihardcore boson system. Thus the pair supersolid state emerges basing on the order-by-disorder mechanism, by which hardcore bosons avoid classical frustration on the triangular lattice. Without on-site repulsion, the transitions between the pair supersolid and the atom superfluid or pair superfluid are first order, except for the particle-hole symmetric point. With weak on-site repulsion and atom hopping turning on, the transition between the pair supersolid and pair superfluid phase becomes continuous. The transition between solid and pair supersolid is three-dimensional XY university, with dynamical exponent z=1 and correlation exponent ν=0.67155. The thermal melting of pair supersolid belongs to the two-dimensional Ising university. We check both energetic and mechanical balance of pair supersolid phase. Lowering the three-body constraint, no pair supersolid is found due to the absence of degeneracy of pair solids in classical limits. We describe the experimental realization of pair tunneling on state dependent lattice. © 2013 American Physical Society.


Hou Y.,Taiyuan University of Technology | Hou Y.,Tohoku University | Chen L.,Tohoku University | Liu P.,Tohoku University | And 5 more authors.
Journal of Materials Chemistry A | Year: 2014

We report a flexible asymmetric supercapacitor assembled by polypyrrole (PPy) and manganese oxide supported by ultrathin three-dimensional nanoporous gold (NPG) electrodes. The highly conductive and free-standing NPG films act as both supports of the active materials and current collectors of the supercapacitor, which evidently enhance the specific capacitance of active materials of both the conducting polymer and the metal oxide. The high energy density and high power density can be realized from the PPy-NPG//MnO 2-NPG asymmetric supercapacitor because of the wide cell voltage in an aqueous electrolyte and high specific capacitances of both PPy and MnO 2 enhanced by NPG. This journal is © the Partner Organisations 2014.


Zhu Z.,Beijing Materials University | Yan H.,Beijing Materials University | Zhang D.,Taiyuan University of Technology | Li W.,University of Science and Technology Beijing | Lu Q.,Beijing Materials University
Journal of Power Sources | Year: 2013

LiNi0.5Mn1.5O4 as a 4.7 V cathode material is prepared through an oxalic acid-pretreated solid-state method. Oxalic acid is added to react with the mixture of LiOH•H2O, MnO2 and Ni(OH)2. This chemical pretreatment results in a sufficient mixing of Li, Ni and Mn ions in the precursor, and therefore promotes the generation of pure LiNi0.5Mn1.5O4 in the following calcination even at a temperature as low as 500 °C. The material prepared at 750 °C has a highest crystallinity and a regular crystal shape with smoothly surface. Compared to traditional method, the LiNi 0.5Mn1.5O4 synthesized by this novel method shows much better electrochemical performances with an initial discharging capacity of 136.9 mAh g-1 and capacity retention of 93.4% after 300 cycles under 0.3C. And most importantly 97.2% of the total capacity displays at 4.7 V, which significantly favors the cell energy density. The novel preparation technique is also available to get high rate performance for LiNi 0.5Mn1.5O4. The material synthesized at 900 °C has a capacity of 121.2 mAh g-1 and stable cycling performance under 3C due to its lower polarization resistance. © 2012 Elsevier B.V. All rights reserved.


Cui Y.,University of Illinois at Urbana - Champaign | Cui Y.,Zhejiang University | Cui Y.,Taiyuan University of Technology | Xu J.,University of Illinois at Urbana - Champaign | And 5 more authors.
Applied Physics Letters | Year: 2011

We experimentally demonstrate an infrared broadband absorber based on an array of nanostrip antennas of several different sizes. The broadband property is due to the collective effect of magnetic responses excited by these nanoantennas at distinct wavelengths. By manipulating the differences of the nanostrip widths, the measured spectra clearly validate our design for the purpose of broadening the absorption band. © 2011 American Institute of Physics.


Li D.-A.,Taiyuan University of Technology | Wang H.-B.,Taiyuan University of Technology | Zhao J.-M.,Taiyuan University of Technology | Yang X.,Purdue University Calumet
Materials Chemistry and Physics | Year: 2011

The objective of this study is to develop microwave absorbers using both dielectric and magnetic lossy materials. Polypyrrole (PPY) is used as dielectric lossy materials and carbonyl iron particles is used as magnetic lossy materials. Polypyrrole powders are prepared by in situ polymerization method. Then PPY-carbonyl iron composite with different mixture ratios have been prepared by as-prepared material. The structure, morphology and properties of the composites are characterized with IR, XRD, scanning electron microscope (SEM), Net-work Anlyzer. The complex permittivity (′r-j ′′r) and reflection loss (dB) of the composites have been measured at different microwave frequencies in S-band and C-band (30-6000 MHz) employing vector network analyzer model HP 8722ET vector. The effect of the mass ratio of PPY-carbonyl iron on the microwave loss properties of the composites is investigated. A possible microwave absorbing mechanism of PPY-carbonyl iron composite has been proposed. The PPY-carbonyl iron composite can find applications in suppression of electromagnetic interference (EMI), and reduction of radar signature. © 2011 Elsevier B.V. All rights reserved.


Zhao J.-M.,Taiyuan University of Technology | An W.-X.,Taiyuan University of Technology | Li D.-A.,Taiyuan University of Technology | Yang X.,Purdue University Calumet
Synthetic Metals | Year: 2011

SiC powders were synthesized from the Si/C system in a nitrogen atmosphere by combustion synthesis. The carbon fiber/SiC composite with different mixture ratios have been prepared by as-prepared material. The structure, morphology and properties of the composites are characterized with IR, XRD, scanning electron microscope (SEM), Network Analyzer. The complex permittivity (ε′r-jε″r) and reflection loss (dB) of the composites have been measured at different microwave frequencies in S-band and C-band (30-6000 MHz) employing vector network analyzer model PNA 3629D vector. The effect of the mol ratio of carbon fiber/SiC on the microwave loss properties of the composites is investigated. A possible microwave absorbing mechanism of carbon fiber/SiC composite has been proposed. The carbon fiber/SiC composite can find applications in suppression of electromagnetic interference (EMI), and reduction of radar signature. © 2011 Elsevier B.V. All rights reserved.


Yan S.,Taiyuan University of Technology | Gao L.,Taiyuan University of Technology | Gao L.,University of Western Australia | Zhang S.,Beihang University | And 2 more authors.
Electrochimica Acta | Year: 2013

Au nanoparticles (AuNPs) supported on activated carbon (Au/C) were prepared by a modified chemical reduction method. The morphology, structure, surface chemical state and electro-oxidation activity of AuNPs were investigated by the transmission electron microscope (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV) and chronoamperometry. Results indicated that the Au/C catalyst possessed small AuNPs with a certain number of gold oxide species. This intrinsic property resulted in the high catalytic activity of the Au/C catalyst for the electro-oxidation of alcohol molecule. The peak values of anodic mass-specific current densities on AuNPs reached 69.5, 442 and 660 mA mg-1Au, respectively in 0.1 M KOH solutions with 6 M methanol, 2 M ethanol and 0.5 M ethylene glycol. © 2013 Elsevier Ltd. All rights reserved.


Zhang M.,Taiyuan University of Technology | Wu S.,Taiyuan University of Technology | Wang Y.,Shanxi Coking Coal Group Co.
Safety Science | Year: 2012

While coal seam is being mined, an annular fissure circle with gas accumulation will be formed in the fissure zone as a result of desorption, dissipation and permeation of gas in the goaf area and overlying strata due to fissures from rock caving and mitigation in the roof. The methods for computation of spatial locations of the fissure circle are researched in this paper. Based on these methods, gas drainage technique for the fissure zone is optimized. By applying drill hole returning water method of variables, the height of caving zone that most affects the drainage effects of inclined high dip drill hole was measured on the site. Due to the consistency of the expected height with the computed height of caving lines at different positions, the correctness of the theoretical computation method is further validated. Meanwhile, the parameters of the inclined high dip drill hole at #3311 working face of Hexi Coal Mine are determined by a case study. © 2011 Elsevier Ltd.


Zhao Z.,Taiyuan University of Technology | Cui X.,Taiyuan University of Technology | Zhang H.,Sany Automation Technology Co.
Advanced Materials Research | Year: 2012

The advantage and potential applications of cloud storage technology in video surveillance, on the basis of the concept and technology character of the cloud storage, have been discussed in the paper. Some important problems of the cloud storage technology applications in video surveillance have also been analyzed. © (2012) Trans Tech Publications, Switzerland.


Cui J.L.,Ningbo University of Technology | Zhang X.J.,China University of Mining and Technology | Deng Y.,Beihang University | Fu H.,China University of Mining and Technology | And 3 more authors.
Scripta Materialia | Year: 2011

α-In2Se3 has a two-layer structure with 1/3 of the cation sites vacant. After addition of Ag to In2Se3, we identified the main phase as In5AgSe8 with nanoinclusions of InSe forming in situ. Ag incorporation favors the formation of Ag2Se slab, which is largely responsible for the decrease in band gap Eg, accounting for much of the increase (decrease) in electrical conductivity (Seebeck coefficient). This effect, combined with a reduction in lattice thermal conductivity, results in a big improvement in thermoelectric property over α-In2Se3. © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.


Shen L.,Taiyuan University of Technology | Wang P.,China Agricultural University | Zhang L.,China Agricultural University
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2011

Aiming at reducing agricultural pollution caused by plastic film, effect of degradable film on soil temperature, soil moisture, maize growth and development, maize yield and relevant characteristics were studied through comparing with the plastic film and open field. The results indicated that soil temperature at surface and 10 cm depth in two months after sowing, soil moisture in 0-20 and >20-40 cm profile from sowing to big trumpet stage, were all higher for degradable film covering than open field. Growth progress, seedling rate, root number during shooting stage, plant height, leaf area and dry weight of maize in different stages were all higher for degradable film covering. Kernel number, thousand-grain weight, and yield of maize under degradable film covering were increased by 9.6%, 20.9%, 35.1% respectively. Degradable film did not show significant difference with plastic film, and it could be applied to agriculture instead of plastic film.


Zhang X.,Taiyuan University of Technology | Liu X.,Taiyuan University of Technology | Wang Z.J.,Taiyuan University of Technology | Wang Z.J.,Virginia Wesleyan College
Engineering Applications of Artificial Intelligence | Year: 2013

The kernel function is the core of the Support Vector Machine (SVM), and its selection directly affects the performance of SVM. There has been no theoretical basis on choosing a kernel function for speech recognition. In order to improve the learning ability and generalization ability of SVM for speech recognition, this paper presents the Optimal Relaxation Factor (ORF) kernel function, which is a set of new SVM kernel functions for speech recognition, and proves that the ORF function is a Mercer kernel function. The experiments show the ORF kernel function's effectiveness on mapping trend, bi-spiral, and speech recognition problems. The paper draws the conclusion that the ORF kernel function performs better than the Radial Basis Function (RBF), the Exponential Radial Basis Function (ERBF) and the Kernel with Moderate Decreasing (KMOD). Furthermore, the results of speech recognition with the ORF kernel function illustrate higher recognition accuracy. © 2013 Elsevier Ltd. All rights reserved.


Cao S.,Taiyuan University of Technology | Cao S.,Ningbo University of Technology | Zheng J.,Ningbo University of Technology | Zhao J.,CAS Changchun Institute of Optics and Fine Mechanics and Physics | And 6 more authors.
Journal of Materials Chemistry C | Year: 2013

We demonstrate a strategy for the growth of Mn2+ ion doped cadmium based II-VI semiconductor quantum dots (QDs) with a designed buffer layer of ZnS (MnS/ZnS/CdS or Mn:CdS QDs), which aims to meet the challenge of obtaining highly efficient and well-resolved Mn2+ ion emission. First, small, high quality MnS cores are obtained by using thiols to replace conventional alkyl amines as capping ligands. Then a buffer layer of ZnS with a tailored thickness is introduced to the QDs before the growth of CdS shells to reduce the size mismatch between the Mn2+ (dopant) and Cd 2+ (host) ions. The fabricated MnS/ZnS/CdS core/shell QDs exhibit a high PL QY of up to 68%, which is the highest ever reported for any type of Mn2+ ion doped cadmium based II-VI semiconductor QD. The photoluminescence (PL) of the QDs consists of well-resolved Mn2+ ion emission without any detectable emission from the CdS band edge or surface defects. In addition, our MnS/ZnS/CdS QDs cannot only be made water-soluble, but can also be coated by ligands with short carbon chain lengths, nearly without cost to the PL QY, which could make them strong candidates for practical applications in biology/biomedicine and opto/electronic devices. © The Royal Society of Chemistry 2013.


Wang Y.,Taiyuan University of Technology | Wang Y.,Nanjing Southeast University | Zheng J.,Taiyuan University of Technology | Zhang M.,Taiyuan University of Technology | Wang A.,Taiyuan University of Technology
IEEE Photonics Technology Letters | Year: 2011

We propose and experimentally demonstrate an approach to generate ultra-wideband (UWB) pulse based on period-one oscillation of semiconductor laser. The baseband UWB signal with - 10-dB bandwidth of 5.59 GHz is generated when the gain-switched pulse train is injected into the slave laser diode. Moreover, the center frequency of the generated UWB signal can be continuously tuned and converted up to 19.53 GHz by adjusting the optical frequency detuning in optical domain directly. © 2011 IEEE.


Lu L.,North University of China | Zhang S.,Beihang University | Yan S.,Taiyuan University of Technology
International Journal of Electrochemical Science | Year: 2015

AuNi/C catalyst (AuNi nanoparticles supported on activated carbon) is prepared by a polyol reduction process. The alloying between Au and Ni and the removal of unalloyed Ni are achieved by the heat and acid treatment. The electrochemical measurement results indicate that the alloying treatment process is favourable to improve the electrocatalytic activity of the AuNi/C catalyst. Moreover, the area-specific electrochemical activity of each AuNi/C catalyst is better than that of the Au/C catalyst, showing the effect of the Ni component on the electrocatalytic activity of the Au/C catalyst is significant. © 2015 The Authors.


Jiang J.,Taiyuan University of Technology | Huo Z.,China Agricultural University | Feng S.,China Agricultural University | Feng S.,Yangzhou University | Zhang C.,Taiyuan University of Technology
Field Crops Research | Year: 2012

Sustainable development of agriculture is restricted by fresh water shortage and water quality deterioration in some arid and semi-arid areas. Therefore, deficit irrigation and saline water irrigation have to be applied for sustaining crop yield. In order to determine the rational irrigation management practice in an arid region of Northwest China, field experiments were conducted in 2008, 2009 and 2010 to study the effects of irrigation amount and water salinity on water consumption and water productivity of spring wheat. Altogether nine irrigation treatments including three levels of irrigation water amount with 375, 300, and 225mm (w1, w2 and w3) and three levels of irrigation water salinity with 0.65, 3.2, and 6.1dSm -1 (s1, s2 and s3) were arranged in a randomized split-plot design with three replications for each treatment. In 2008, yield increased with increasing irrigation amount under both fresh and saline water irrigation. However, in 2009 and 2010, the highest yield at the same salinity level under saline water irrigation was obtained by w2. Actual evapotranspiration (ET a) decreased with decreasing irrigation amount. Therefore, w2 got higher water use efficiency (WUE) (1.25-1.63kgm -3) and irrigation water use efficiency (IWUE) (2.11-2.36kgm -3) than w1, which indicated that irrigation amount 300mm is beneficial to yield and water use efficiency at water salinity 3.2 and 6.1dSm -1. Thus, for the purpose of highest yield and WUE, irrigation amount should be controlled at appropriate level under saline water irrigation. The effect of irrigation water salinity on ET a was significant in 2009 and 2010, while the effect on yield, WUE and IWUE was only significant in 2010. However, the differences of yield, ET a, WUE and IWUE between s2 and s1 were statistically insignificant in the 3 years. It can be concluded that irrigation water salinity 3.2dSm -1 has no significant effect on wheat yield and water productivity. The interaction effects of irrigation amount and water salinity on yield, ET a and WUE were statistically insignificant in the experiments. © 2012 Elsevier B.V.


Wang J.,New Mexico State University | Krishna R.,University of Amsterdam | Yang J.,Taiyuan University of Technology | Dandamudi K.P.R.,New Mexico State University | Deng S.,New Mexico State University
Materials Today Communications | Year: 2015

Nitrogen-doped microporous activated carbon adsorbents were synthesized by a self-template method with KOH as the porogen agent at pyrolysis temperatures of 600, 700, and 800°C. The carbon adsorbent samples were characterized with N2 adsorption at 77K, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, thermal gravimetric analysis, Raman spectroscopy, Fourier transformed infrared spectroscopy, and energy-dispersive X-ray spectroscopy mapping. Single component gas adsorption equilibrium of CO2, CH4, and N2 on the carbon adsorbents were measured at gas pressures up to 100kPa and temperatures of 273, 298, and 323K. Adsorption breakthrough performance of a fixed bed packed with the carbon adsorbents for separation of CO2/CH4/N2 gas mixture was simulated using the adsorption equilibrium data collected in this work. A high CO2 adsorption capacity (6.36mmolg-1 on N-AC 600 at 100kPa and 273K) and large selectivites for the separation of CO2/CH4 (9.2), CO2/N2 (47.3) and CH4/N2 (3.6) mixtures were achieved with the carbon adsorbents due to their N-containing groups, narrow pore size distribution, and large specific surface area. The nitrogen-doped porous carbon adsorbents look very promising for flue gas treatment and natural gas upgrading applications. © 2015.


Yang Y.,Taiyuan University of Technology | Ji C.,China Building Material Geology Investigation Center Shanxi Unit | Kang T.,Taiyuan University of Technology | Chai Z.,Taiyuan University of Technology
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2011

The deformation characteristics of surrounding rock after excavating and supporting of coal roadway with great-thick mudstone roof, its failure mechanism and its controlling countermeasures are systematically researched through field investigation, laboratory test, numerical testing, similar simulation and theoretical analysis. Meanwhile these methods are used to represent dynamically the process of rock deformation and failure in the roadways, and the roadway's behaviors including deformation characteristics, failure mechanisms, stress distribution in the surrounding rocks and the effects of various support systems on roadway stability are studied. Some conclusions can be drawn as follows:(1) The fracture, cracking and separating layer of the thick mudstone roof occurred and promoted promote by two ways, such as the weathering, disintegrating, disruption, dilatancy of the mudstone, as well as the concentrated tensile stress and shear stress in the stress adjustment. (2) Based on the study, it is shown that the original supports in the absence of accurate judgment of the surrounding rock result in the roadway destruction and the supports system abated. (3) The principles to support the mudstone roof are enclosing in time, enhancing the stiffness of the lower rock layer of the roof and disposing the anchor cables along the cracks. (4) Based on the geological mechanics and environmental conditions of the roadway surrounding rock, an optimized roadway support design is provided that effectively avoid the multiple recondition by changing the cross-section and modulating the support parameters. The long-term stability of the thick mudstone roof had been realized. After several successful engineering practices, research results have been adopted in Qipanjing mining area;and the results have great theoretical and practical values to similar roadway supports.


Wang N.,Shandong University | Bai Z.,Taiyuan University of Technology | Qian Y.,Shandong University of Science and Technology | Yang J.,Shandong University
Advanced Materials | Year: 2016

Double-walled Sb@TiO2- x nanotubes take full advantage of the high capacity of Sb, the good stability of TiO2- x, and their unique interaction, realizing excellent electrochemical performance both in lithium-ion batteries and sodium-ion batteries. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Jiang T.,Linyi Normal University | Li M.,Taiyuan University of Technology | Chen C.S.,University of Southern Mississippi
Numerical Heat Transfer; Part A: Applications | Year: 2012

A new version of the method of particular solutions (MPS) has been proposed for solving inverse problems for nonhomogeneous convection-diffusion equations with variable coefficients (IPCD). Coupled with the time discretization and MPS, the proposed method is a truly meshless method which requires neither domain or boundary discretization. Even though the final temperature is almost undetectable or is disturbed by significant noise, the proposed method can still recover the initial temperature very well. The effectiveness of the proposed inverse scheme using radial basis functions is demonstrated by several examples in 2-D and 3-D. Copyright © Taylor & Francis Group, LLC.


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.


Li Z.,Taiyuan University of Technology | Yan X.,Wuhan University of Technology
Insight: Non-Destructive Testing and Condition Monitoring | Year: 2013

The sensor fusion of multi-sensory measurements is believed to improve the defect detection ability for machinery condition monitoring. A new fault diagnosis method for rolling bearings based on the sensor fusion of oil analysis data, microscopic debris analysis data and vibration analysis data is proposed in this paper. Multi-dimensional sensors were used to record the tribological and vibration data of rolling bearings in typical fault experiments. Oil and microscopic debris analysis was applied to obtain the wear particle number and size distribution, chemical compositions and particle textures, etc. Wavelet transform (WT) and empirical mode decomposition (EMD) were employed to attain the distinguishing features of the vibration data. Then, an intelligent data fusion method based on principal component analysis (PCA) and a genetic algorithm fuzzy neural network (GAFNN) was employed to identify the rolling bearing conditions. Experimental tests have been carried out to evaluate and verify the proposed method. The analysis results show that the fault detection model using the sensor fusion technique produces superior results to those using single measurements and thus it has application importance.


Su P.,Taiyuan University of Technology | Liao H.,State Key Laboratory of Hydraulics and Mountain River Engineering
Shuili Fadian Xuebao/Journal of Hydroelectric Engineering | Year: 2012

Shape parameters of bottom aerator adopted by an actual project are analyzed for its cavity properties with numerical simulation based on an orthogonal design method. The weight coefficients of all influencing factors, near-wall cavity length and middle cavity length, etc., are calculated by range and variance analysis. The results provide a theoretical foundation and a reference for shape design of aerator.


Zhang A.,Taiyuan University of Technology | Wang X.,Taiyuan University of Technology | Wang X.,Zhuzhou Electrical Company | Jia W.,Taiyuan University of Technology | And 2 more authors.
IEEE Transactions on Power Electronics | Year: 2014

The brushless doubly fed induction machine (BDFIM) shows potential in replacing the wound rotor machines for certain industrial applications due to its higher reliability, a benefit of the absence of brush gears. This paper proposes an indirect stator-quantities control (ISC) strategy for the BDFIM. Theoretical derivation has been carried out to demonstrate the control principle for the proposed strategy. ISC provides the benefit of a simple structure, since it is implemented in two static reference frames and no rotating coordinate transformation is required. Furthermore, only two stator winding resistances are used, and therefore, the controller structure is less dependent on machine parameters. The experimental results of the prototype show the feasibility of the proposed strategy for the BDFIM. © 2013 IEEE.


Cheng K.-K.,Tsinghua University | Liu Q.,Tsinghua University | Liu Q.,Taiyuan University of Technology | Zhang J.-A.,Tsinghua University | And 3 more authors.
Process Biochemistry | Year: 2010

Corncob acid hydrolysate, detoxed by sequently boiling, overliming and activated charcoal adsorption, was used for 2,3-butanediol production by Klebsiella oxytoca ACCC 10370. The effects of acetate in hydrolysate and pH on 2,3-butanediol production were investigated. It was found that acetic acid in hydrolysate inhibited the growth of K. oxytoca while benefited the 2,3-butanediol yield. With the increase in acetic acid concentration in medium from 0 to 4 g/l, the lag phase was prolonged and the specific growth rate decreased. The acetic acid inhibition on cell growth can be alleviated by adjusting pH to 6.3 prior to fermentation and a substrate fed-batch strategy with a low initial acetic acid concentration. Under the optimum condition, a maximal 2,3-butanediol concentration of 35.7 g/l was obtained after 60 h of fed-batch fermentation, giving a yield of 0.5 g/g reducing sugar and a productivity of 0.59 g/h l. © 2009 Elsevier Ltd. All rights reserved.


Zhang Y.,University of Science and Technology Beijing | Lu Z.P.,University of Science and Technology Beijing | Ma S.G.,Taiyuan University of Technology | Liaw P.K.,University of Tennessee at Knoxville | And 4 more authors.
MRS Communications | Year: 2014

With multiple elements mixed at equal or near-equal molar ratios, the emerging, high-entropy alloys (HEAs), also named multi-principal elements alloys (MEAs), have posed tremendous challenges to materials scientists and physicists, e.g., how to predict high-entropy phase formation and design alloys. In this paper, we propose some guidelines in predicting phase formation, using thermodynamic and topological parameters of the constituent elements. This guideline together with the existing ones will pave the way toward the composition design of MEAs and HEAs, as well as property optimization based on the composition-structure-property relationship. © 2014 Materials Research Society.


Li M.,Taiyuan University of Technology | Chen C.S.,Taiyuan University of Technology | Chu C.C.,National Taiwan University | Young D.L.,National Taiwan University
Engineering Analysis with Boundary Elements | Year: 2014

In this paper, the three-dimensional transient heat conduction problems in functionally graded materials (FGMs) have been solved using the method of fundamental solutions (MFS). To be more specific, we consider the FGMs with thermal conductivity and specific heat vary exponentially in z-direction. In the numerical simulation, we coupled the fundamental solution of diffusion equation with the method of time-space unification which provides a simple and direct approach for solving time-dependent problems. The parameter transformation technique is also utilized to obtain the fundamental solutions which contain the thermal conductivity and the specific heat conditions. The MFS is very attractive in handling problems with irregular domain due to the simplicity of the method. The numerical results are in good agreement comparing with analytical solution and results obtained from the finite element method. © 2014 Elsevier Ltd.


Li M.,Taiyuan University of Technology | Chen W.,Hohai University | Chen C.S.,Taiyuan University of Technology | Chen C.S.,University of Southern Mississippi
Engineering Analysis with Boundary Elements | Year: 2013

In this paper we present a localized meshless method using radial basis functions (RBFs) for solving up to six dimensional problems. To improve the difficulty of selecting a shape parameter of RBF-MQ, a normalized scheme is introduced. We also make a comparison between the global and local RBF methods in terms of stability and accuracy. To demonstrate the applicability of the localized RBF method for high dimensional problems, two numerical examples with Dirichlet boundary conditions are given. © 2013 Elsevier Ltd.


Li X.,Taiyuan University of Technology | Wang Z.,Taiyuan University of Technology | Zhu F.,Wayne State University | Wu G.,Taiyuan University of Technology | Zhao L.,Taiyuan University of Technology
International Journal of Impact Engineering | Year: 2014

Corrugated sandwich panels are widely used in various fields because such panels have lower density, easier fabrication methods and higher strength compared with monolithic plates. In this study, the dynamic response of corrugated sandwich panels under air blast loading was investigated using a ballistic pendulum system. Two configurations of the specimen were considered. The residual deflection of the back face sheet and the deformation/failure modes of the sandwich panel under different impulse levels were analysed. Finite element simulations were performed by using AUTODYN. The deformation process and energy absorption of the face sheets and the core were investigated in the numerical simulation. © 2013 Elsevier Ltd. All rights reserved.


Qiao J.,Taiyuan University of Technology | Jia H.,University of Tennessee at Knoxville | Liaw P.K.,University of Tennessee at Knoxville
Materials Science and Engineering R: Reports | Year: 2016

The mechanical properties of ex-situ and in-situ metallic glass matrix composites (MGMCs) have proven to be both scientifically unique and of potentially important for practical applications. However, the underlying deformation mechanisms remain to be studied. In this article, we review the development, fabrication, microstructures, and properties of MGMCs, including the roomerature, cryogenicerature, and higherature mechanical properties upon quasi-static and dynamic loadings. In parallel, the deformation mechanisms are experimentally and theoretically explored. Moreover, the fatigue, corrosion, and wear behaviors of MGMCs are discussed. Finally, the potential applications and important unresolved issues are identified and discussed. © 2015 Published by Elsevier B.V. All rights reserved.


Cheng K.-K.,Tsinghua University | Wang W.,Taiyuan University of Technology | Zhang J.-A.,Tsinghua University | Zhao Q.,Taiyuan University of Technology | And 2 more authors.
Bioresource Technology | Year: 2011

In this study, a central composite design of response surface method was used to optimize sulfite pretreatment of corncob residues, in respect to sulfite charge (5-10%), treatment time (1-2h), liquid/solid (l/s) ratio (6:1-10:1) and temperature (150-180°C) for maximizing glucose production in enzymatic hydrolysis process. The relative optimum condition was obtained as follows: sulfite charge 7.1%, l/s ratio 7.6:1, temperature 156°C for 1.4h, corresponding to 79.3% total glucan converted to glucose+cellobiose. In the subsequent simultaneous saccharification and fermentation (SSF) experiments using 15% glucan substrates pretreated under this kind of conditions, 60.8g ethanoll-1 with 72.2% theoretical yield was obtained. © 2010 Elsevier Ltd.


Xu L.-C.,Taiyuan University of Technology | Du A.,Queensland University of Technology | Kou L.,Queensland University of Technology
Physical Chemistry Chemical Physics | Year: 2016

The recent synthesis of monolayer borophene (triangular boron monolayer) on a substrate has opened the era of boron nanosheets (Science, 2015, 350, 1513), but the structural instability and a need to explore the novel physical properties are still open issues. Here we demonstrated that borophene can be stabilized by full surface hydrogenation (borophane), from first-principles calculations. Most interestingly, our calculations show that borophane has direction-dependent Dirac cones, which are mainly caused by the in-plane px and py orbitals of boron atoms. The Dirac fermions possess an ultrahigh Fermi velocity of up to 3.5 × 106 m s-1 under the HSE06 level, which is 4 times higher than that of graphene. The Young's moduli are calculated to be 190 and 120 GPa nm along two different directions, which are comparable to those of steel. The ultrahigh Fermi velocity and good mechanical features render borophane ideal for nanoelectronic applications. © 2016 the Owner Societies.


Qiao J.W.,Taiyuan University of Technology | Qiao J.W.,University of Science and Technology Beijing | Jia H.L.,University of Tennessee at Knoxville | Zhang Y.,University of Science and Technology Beijing | And 2 more authors.
Materials Chemistry and Physics | Year: 2012

Analysis of energy dissipation during shear-banding aids to understand plastic deformations of bulk metallic glasses (BMGs). For Zr 55Al 10Ni 5Cu 30 BMGs at 298 K, multi-step shearing is proposed, and the thermal energy during serrations cannot result in a temperature rise (ΔT) higher than T m. At 77 K, N-step shearing is supposed. When N is in the range of 24-47, it is reasonable to deduce the resulting temperature from 0.8T g to T m, accompanied by a continuous plastic deformation. Highlights: Multi-step shearing is reasonable to analyze energy conversion upon shear banding. At 77 K, the serrations disappear, and an N-step method is chosen to analyze the energy dissipation. The present investigation gives a proper method to reveal the shear banding for BMGs at different temperatures. © 2012 Published by Elsevier B.V. All rights reserved.


Ji J.,Taiyuan University of Technology | Zhou Z.,Tsinghua University | Yang X.,Tsinghua University | Zhang W.,Taiyuan University of Technology | And 2 more authors.
Small | Year: 2013

Interconnection of one-dimensional nanomaterials such as nanowires and carbon nanotubes with other parts or components is crucial for nanodevices to realize electrical contacts and mechanical fixings. Interconnection has been being gradually paid great attention since it is as significant as nanomaterials properties, and determines nanodevices performance in some cases. This paper provides an overview of recent progress on techniques that are commonly used for one-dimensional interconnection formation. In this review, these techniques could be categorized into two different types: two-step and one-step methods according to their established process. The two-step method is constituted by assembly and pinning processes, while the one-step method is a direct formation process of nano-interconnections. In both methods, the electrodeposition approach is illustrated in detail, and its potential mechanism is emphasized. Techniques used for interconnection formation, which is crucial for nanodevice performance, are categorized into two types. The two-step method is constituted by assembly and pinning processes, while the one-step method is a direct formation process of nano-interconnections. In both methods, contact resistances are compared and the electrodeposition approach is emphasized. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Wang R.,Taiyuan University of Technology | Wang R.,Tsinghua University | Han L.-H.,Tsinghua University | Hou C.-C.,Tsinghua University
Journal of Constructional Steel Research | Year: 2013

This paper reports an investigation into the impact performance of concrete filled steel tubular (CFST) members. A series of tests were carried out to obtain the failure modes and the time history of the impact forces for the composite components under lateral impact. The testing parameters include the axial load level on CFST specimens, constraining factor and the impact energy. A finite element analysis (FEA) model was developed, in which the strain rate effects of steel and concrete materials, interaction between the steel tube and the core concrete, as well as the confinement effect of the outer steel tube provided to the core concrete were considered. The test data were then used to verify the accuracy of the FEA model and generally a good agreement was achieved. A full-range analysis on the impact behavior of CFST member was performed by using the FEA model. © 2012 Elsevier Ltd. All rights reserved.


Wang S.,Jilin University | Wang S.,Taiyuan University of Technology | Li G.,Jilin University | Huo Q.,Jilin University | Liu Y.,Jilin University
Inorganic Chemistry Communications | Year: 2013

Two new coordination polymers, |DMF|[Zn2(C7N 2O4H6)2(C10N 2H8)] (1) and |(H2O)3|[Co(C 8N2O4H9)2(H 2O)2] (2) have been synthesized based on 2-ethyl-1H-imidazole-4,5-dicarboxylic acid (H3EtImDC) and 2-propyl-1H-imidazole-4,5-dicarboxylic acid (H3PrImDC) as organic ligands, respectively. Single-crystal X-ray diffraction analysis reveals that compound 1 is a two dimensional layered structure constructed from two types of six-membered metallocycle, and the layers are stacked in an -ABCABC- sequence. For 2, the mononuclear [Co(C8N2O4H 9)2(H2O)2] molecules are connected with each other through hydrogen bonds forming a three dimensional supermolecular structure. Further characterizations including elemental analyses, IR spectra, and thermogravimetric analyses have been studied. © 2013 Elsevier B.V.


Qiao J.W.,Taiyuan University of Technology | Zhang Y.,University of Science and Technology Beijing | Jia H.L.,University of Tennessee at Knoxville | Yang H.J.,Taiyuan University of Technology | And 2 more authors.
Applied Physics Letters | Year: 2012

A Ti-based metallic-glass-matrix composite exhibits tensile softening (necking) in the supercooled liquid region, accompanied by a large tensile ductility and a fragmentation of dendrites. Subjected to high temperatures, concurrent crystallization does not occur, suggesting a good thermal stability of the glass matrix. The presence of high-volume-fractioned dendrites lowers the rheology of the viscous glass matrix at high temperatures, which results in an absence of super elongation as monolithic bulk metallic glasses (BMGs). A tensile strength of 970 MPa is higher than those of most BMGs under varying strain rates, ascribing to the retardation of softening by the dendrites. © 2012 American Institute of Physics.


Huang D.,Chongqing University | Huang D.,Key Laboratory of New Technology for Construction of Cities in Mountain Area | Li Y.,Taiyuan University of Technology
International Journal of Rock Mechanics and Mining Sciences | Year: 2014

Axisymmetric triaxial compression loading-unloading tests are conducted on twenty-seven marble specimens with initial confining pressures of 20, 30 and 40. MPa and unloading rates of 0.1, 1.0 and 10. MPa/s. It is found that magnitude of initial confining pressure and unloading rate significantly influence rock failure modes and strain energy conversion (accumulation, dissipation and release) during unloading. The failure mode of rock specimen is gradually changed from shear to tensile with increasing unloading rate. The pre-peak conversion rate of strain energy is increased with increasing unloading rate. This increase trend is enhanced by initial confining pressure. The post-peak conversion rate of strain energy has the similar increasing pattern of the pre-peak one, though it is several to ten times greater. Much strain energy is released after peak strength from the tested specimen and it may account for the occurrence of flying fragments. The higher the unloading rate and/or the initial confining pressure, the more severe the "flying fragment" phenomenon. The characteristics of strain energy accumulation, dissipation and release are investigated in three stages, i.e., elastic compression, pre-peak unloading, and post-peak fracturing. The rule of strain energy conversion for each stage is derived, and triaxial unloading tests and conventional triaxial compression are compared in terms of strain energy and its conversion. © 2013 Elsevier Ltd.


Yao X.-L.,Taiyuan University of Technology | Liu Y.,Harbin Institute of Technology | Liu Y.,Ecole Polytechnique - Palaiseau | Yan X.,University of Management and Economics
Energy Policy | Year: 2014

A one-year subsidy program for energy-efficient home appliances has been implemented in China. We construct a dataset consisting of participant and non-participant households in both urban and rural areas of Rizhao city. By applying a quantile regression and counterfactual analysis, this study disentangles the impact of this subsidy program and inherent household attributes on per capita residential electricity consumption. First, contrary to the mean regression, the elasticity of electricity consumption to household[U+05F3]s income, age, education and energy-saving awareness, varies markedly across the electricity consumption distribution and shows discrepancy between urban and rural areas. Second, while inherent household attributes are identified as a primary determinant to the changes in residential electricity consumption, the effect induced by the subsidy incentive is more significant at the middle of the electricity consumption distribution than at the tails. Third, there are significant rebound effects that lead to overall increase in household electricity consumption. Our results suggest that the disparity between urban and rural regions and targeted consumer behavior changes should be taken into account to ensure the effectiveness of a future energy-efficient subsidy program. © 2014 Elsevier Ltd.


Chen B.-Y.,Hebei Medical University | Chen B.-Y.,Bethune International Peace Hospital of PLA | Ma J.-X.,Hebei Medical University | Wang C.-Y.,Bethune International Peace Hospital of PLA | Chen W.-Y.,Taiyuan University of Technology
Graefe's Archive for Clinical and Experimental Ophthalmology | Year: 2012

Background The study aims to determine the changes in the biomechanical properties of the anterior and extreme posterior portions of experimental near-sighted eyes by examining the mechanical behavior of guinea pig scleral desmocytes, thus finding a new approach to the pathogenesis of myopia and their corresponding therapies. Methods Guinea pigs (2 weeks old) were numbered and assigned into three groups (A, B, and C) with ten guinea pigs each. Concave lens-induced myopic (LIM) animal models were prepared via the out-of-focus method. The other eye in the same guinea pig served as the self-control (SC) group. After modeling groups A, B, and C for 6, 15, and 30 days respectively, the lenses from the guinea pigs in the experimental group were removed. The scleral fibroblasts in each group were cultured, and passaged twice in vitro. The micropipette aspiration technique coupled with a viscoelastic solid model was utilized to investigate the viscoelastic properties of the scleral fibroblasts in normal and myopic guinea pigs. The mechanical behavior of the scleral desmocytes of the LIM and SC groups were compared. Results The mechanical behavior of the scleral desmocytes was compared between the LIM and SC groups. The Young's modulus at equilibrium and the apparent cellular viscosity of the anterior portion of the sclera in the LIM group at 6 days and 15 days after myopic induction were not significantly different from that of the SC group (P<0.05). However, the results for the anterior portions of the sclera in the LIM group at 30 days were significantly higher than those of the LIM group at 6 and 15 days, as well as those in the SC group (P<0.05). The Young's modulus at equilibrium and the apparent cellular viscosity of the extreme posterior portions of the sclera in the LIM group at 6 days after myopic induction not significantly from those of the SC group (P<0.05). However, the results for the extreme posterior portions of the sclera in the LIM group after 15 days and 30 days were significantly higher than those in the LIM group at 6 days and the SC group (P<0.05). Conclusions The Young's modulus at equilibrium or apparent cellular viscosity of all the anterior portions of the sclera in the LIM group were longer than those in the SC group at 30 days after the induction, and the results for all the extreme posterior portions of the LIM group were larger than those of the SC group on the 15th and 30th day. Therefore, the Young's modulus and apparent viscosity of the anterior and extreme posterior portions of the sclera changed on the 15th and 30th day after induction respectively. © 2011 Springer-Verlag.


Xue J.,Taiyuan University of Technology | Xue J.,Key Laboratory of Interface Science and Engineering in Advanced Materials | Shen Q.,Taiyuan University of Technology | Liang W.,Taiyuan University of Technology | And 4 more authors.
Electrochimica Acta | Year: 2013

CdSe nanoparticles with well-defined crystallinity were assembled into vertically aligned TiO2 nanotube arrays (TiO2 NTAs) by cyclic voltammetry electrochemical deposition with an aim to tune the response of photoelectrochemical cell in visible region. Through this method, CdSe nanocrystals were deposited into intra- and inter-tubular space of the TiO 2 nanotubes (TNTs) to form three-dimensional (3D) multijunction structure. The amount of SeO2 added during electrodeposition of CdSe played an important role in formation of the heterostructures. A maximum short-circuit photocurrent of 7.72 mA/cm2 and open circuit potential of 1.24 V were achieved under visible light illumination. The remarkable photoresponse should ascribe to the high-quality of 3D multijunction structure. Such heterostructure system would serve as a promising candidate for solar energy conversion. © 2013 Elsevier Ltd. All rights reserved.


Wang Z.,Taiyuan University of Technology | Yu H.,Harbin Institute of Technology
Theoretical and Applied Fracture Mechanics | Year: 2015

An extended-finite-element-based method is proposed to accommodate the arbitrary motion of a crack in a general two-dimensional domain containing different kinds of material interfaces. To obtain the accurate stress intensity factors (SIFs) when the crack tip approaches the interface, the interpolation method in the vicinity of the crack tip employed in the extended finite element method (XFEM) is replaced with one that is derived from a moving mesh patch. Mesh configurations in this patch are the same as that adopted in the finite element method (FEM) for crack problems. The boundary of the patch is required to be coincident with background-mesh element edges and only the patch mesh works during the computation. As a result, the major advantages of the XFEM for modeling crack growth are preserved. The simulations are accomplished using a new domain expression of an interaction integral for evaluating stress intensity factors, and the maximum hoop stress criterion for crack-growth direction prediction. Several numerical examples are presented to prove the capability and practicability of the proposed technique and the program. © 2014 Elsevier Ltd.


Teng K.,Taiyuan University of Technology | Zhang C.,Harbin Institute of Technology
Nonlinear Analysis: Real World Applications | Year: 2016

In this paper, under some superquadratic conditions made on the nonlinearity f, we use variational approaches to establish the existence of infinitely many solutions to quasilinear elliptic equations with (p,q)-Laplacian -Ⅎpu-Ⅎqu+a(x)|u|p-2u+b(x)|u|q-2u=f(x,u)in ℝ, where 1


Deng K.,Taiyuan University of Technology | Wang C.,Taiyuan University of Technology | Wang X.,Harbin Institute of Technology | Wu K.,Harbin Institute of Technology | Zheng M.,Harbin Institute of Technology
Materials and Design | Year: 2012

In this paper, 1.5vol.% submicron-SiCp/AZ91 composite is fabricated by stir casting technology. After be forged at 420°C with 50% reduction initially, the composite is subjected to extrusion at 370°C with the ratio of 16. Results illustrates that the combination of forging and extrusion process has significant effect on refining grain size and improving particle distribution, which results in the obvious improvement of ambient tensile strength. Tensile testing at elevated temperatures also has been performed on the as-extruded composites at temperatures from 593K to 643K with initial strain rates from 8.3×10-4 to 1.67×10-2s-1. It demonstrates that the composite exhibits higher plasticity at elevated temperatures, which is mainly attributed to significant grain refinement and uniform particle distribution after hot deformation. Besides, the shape of stress-strain curves of submicron-SiCp/AZ91composite depends very sensitively on the strain rate and testing temperature. The strain-rate sensitivity exponent m is about 0.4 in the temperature and strain-rate range investigated, which suggests that the deformation probably occurred through grain boundary sliding accommodated by diffusional transport. © 2012 Elsevier Ltd.


Deng K.,Taiyuan University of Technology | Shi J.,Taiyuan University of Technology | Wang C.,Taiyuan University of Technology | Wang X.,Harbin Institute of Technology | And 3 more authors.
Composites Part A: Applied Science and Manufacturing | Year: 2012

One kind of (submicron + micron) bimodal size SiCp/AZ91 composite was fabricated by the stir casting technology. After hot deformation process, the influence of bimodal size particles on microstructures and mechanical properties of AZ91 matrix was investigated by comparing with monolithic A91 alloy, submicron SiCp/AZ91 and micron SiCp/AZ91 composites. The results show that micron particles can stimulate dynamic recrystallized nucleation, while submicron particles may pin grain boundaries during the hot deformation process, which results in a significant grain refinement of AZ91 matrix. Compared to submicron particles, micron particles are more conducive to grain refinement through stimulating the dynamic recrystallized nucleation. Besides, the yield strength of bimodal size SiCp/AZ91 composite is higher than that of single-size particle reinforced composites. Among the strengthening mechanisms of bimodal size particle reinforced composite, it is found that grain refinement and dislocation strengthening mechanism play a larger role on improving the yield strength. © 2012 Elsevier Ltd. All rights reserved.


Deng K.K.,Taiyuan University of Technology | Wang X.J.,Harbin Institute of Technology | Zheng M.Y.,Harbin Institute of Technology | Wu K.,Harbin Institute of Technology
Materials Science and Engineering A | Year: 2013

In this paper, 0.2. μm SiCp/AZ91 composite was fabricated by stir casting technology. The influence of fine (<1. μm) particles on the dynamic recrystallization (DRX) behavior of AZ91 matrix was investigated by researching the microstructure evolution of 0.2. μm 1. vol% SiCp/AZ91 composite during the hot extrusion process. Results showed that the DRXed ratio of AZ91 matrix increased as well as the average size of DRXed grains reduced due to the addition of fine particles. The SiCp could not only pin dislocation, but also was helpful to generate dislocations owing to the deformation mismatch between matrix and particles, thus causing the increase of dislocation density around SiCp, which was benefit to stimulate DRX nucleation. Meanwhile, the growth of DRXed grains was suppressed in the following deformation process due to the pinning effect of fine particles on grain boundaries. Thus, the fine particles had significant effect on stimulating DRXed nucleation and refining grain size. The yield strength and ultimate tensile strength of the as-deformed 0.2. μm 1. vol% SiCp/AZ91 composite are 275 and 335. MPa, respectively, which are mainly attributed to the grain refinement, basal plane texture and uniform particle distribution induced by hot deformation. © 2012 Elsevier B.V.


Ouyang T.,Xiangtan University | Chen Y.,Xiangtan University | Xie Y.,Xiangtan University | Wei X.L.,Xiangtan University | And 3 more authors.
Physical Review B - Condensed Matter and Materials Physics | Year: 2010

Graphene nanojunctions (GNJs) are important components of future nanodevices and nanocircuits. Using the nonequilibrium Green's function method, we investigate the phononic properties of three-terminal GNJs (TGNJs). The results show that the heat flux runs preferentially along the direction from narrow to wide terminals, presenting an evident ballistic thermal rectification effect in the asymmetric TGNJs. The rectification efficiency is strongly dependent on the asymmetry of the nanojunctions, which increases rapidly with the width discrepancy between the left and right terminals. Meanwhile, the corner form of the TGNJs also plays an important role in the rectification effect. The mechanism of this thermal rectification is explained by a qualitative analysis. Compared to previous thermal rectifiers based on other materials, the asymmetric nanojunctions based on graphene possess much high rectification ratio which can approach about 200%. These indicate that asymmetric TGNJs might be a promising candidate for excellent ballistic thermal (phononic) devices. © 2010 The American Physical Society.


Xiao B.,Queen's University of Belfast | Xiao B.,Taiyuan University of Technology | Yuan Q.,Aston University | Williams R.A.,University of Birmingham
Chemical Communications | Year: 2013

A new concept of nanoporous metal organic framework particles stabilising emulsions was investigated. The copper benzenetricarboxylate MOF particles adsorbed at the oil/water interface play an exceptional role in stabilising both oil-in-water and water-in-oil emulsions. © 2013 The Royal Society of Chemistry.


Dong Y.,University of Birmingham | Li X.,University of Birmingham | Tian L.,Taiyuan University of Technology | Bell T.,University of Birmingham | And 2 more authors.
Acta Biomaterialia | Year: 2011

Antibacterial surface modification of biomedical materials has evolved as a potentially effective method for preventing bacterial proliferation on the surfaces of devices. However, thin antibacterial coatings or modified layers can be easily worn down when interacting with other surfaces in relative motion, thus leading to a low durability of the antibacterial surface. To this end, novel biomaterial surfaces with antibacterial Ag agents and a wear-resistant S-phase have been generated on stainless steel by duplex plasma silvering-nitriding techniques for application to load-bearing medical devices. The chemical composition, microstructure, surface topography, roughness and wettability of SS surfaces were characterised using glow discharge optical emission spectroscopy, energy-dispersive spectroscopy/wavelength dispersive spectrometry (WDS), X-ray diffraction, atomic force microscopy and a contact angle goniometer. Optimal surface design for high antimicrobial activity and prolonged durability has been achieved, as evidenced by rapid bacterial killing rates (within 6 h), an ultra hard matrix (875 ± 25 Hv), high load-bearing capacity (critical load 37 N) and excellent wear resistance (wear rate 4.9 × 10-6 mm3 m-1). Ag embedded in the hard substrate of fcc compounds M4N (M = Fe, Cr, Ag, etc.) and the expanded fcc nitrogen S-phase shows deep infiltration of 6 ± 1 μm, and provides bactericidal activity against both Gram-negative Escherichia coli NCTC 10418 and Gram-positive Staphylococcus epidermidis NCTC 11047 of over 97% and 90%, respectively, within 6 h. The presence of silver in the surface before and after scratching under a progressive load applied up to 60 N using a diamond stylus was confirmed by WDS. © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.


Chen B.-Y.,Bethune International Peace Hospital of PLA | Wang C.-Y.,Bethune International Peace Hospital of PLA | Chen W.-Y.,Taiyuan University of Technology | Ma J.-X.,Hebei Medical University
Graefe's Archive for Clinical and Experimental Ophthalmology | Year: 2013

Purpose: To determine changes in expression of transforming growth factor β-2 (TGF-β2) and basic fibroblast growth factor (bFGF) in scleral desmocytes from anterior and posterior portions of experimentally-induced myopic eyes of guinea pigs. Methods: Three groups (n = 10) of 2-week-old guinea pigs were used to develop concave lens-induced myopia (LIM) in one eye via the out-of-focus method for 6, 15, or 30 days respectively, while the other eye in each guinea pig served as the self-control (SC). After myopia induction, lenses were removed, and scleral fibroblasts were cultured and passaged twice. TGF-β2 and bFGF expression levels of scleral desmocytes in LIM and SC groups were compared by immunocytochemistry, quantitative real-time PCR (qRT-PCR) and Western blot analyses. Results: The TGF-β2 expression of the anterior portion of the sclera in the LIM group was significantly higher at 15 days, and at its highest at 30 days after myopia induction compared with the SC group (P < 0.05). The TGF-β2 staining of the posterior sclera in the LIM group began to rise significantly at 6 days, peaked at 15 days and remained significantly higher than that of the anterior part, as well as the SC group, even at 30 days after myopia induction (P < 0.05). BFGF levels in scleral desmocytes from the anterior and posterior regions in the LIM group were both significantly lower than those of the SC group at all time points after myopia induction (P < 0.05). Furthermore, as the myopia progressed, bFGF expression in the anterior and posterior sclera in the LIM group gradually and statistically significantly decreased compared with the SC group (P < 0.05); however, no significant differences were observed between the anterior and posterior parts in the LIM group at any time after myopia induction (P > 0.05). All these results were consistent at the mRNA and protein levels. Conclusions: During myopia development in lens-induced guinea pigs, the increase in TGF-β2 activity of scleral desmocytes initiated at the posterior pole. Along with the induction time, the TGF-β2 activity in all scleral desmocytes became elevated. By contrast, the bFGF activity showed a general decline in all scleral desmocytes, rather than mainly in the posterior pole. These results imply that expression of TGF-β2 in scleral desmocytes plays a direct role, while that of bFGF exerts an indirect role in myopia development. © 2013 Springer-Verlag Berlin Heidelberg.


Liang W.,Taiyuan University of Technology | Zhao Y.,Taiyuan University of Technology | Wu D.,Taiyuan University of Technology | Dusseault M.B.,University of Waterloo
Rock Mechanics and Rock Engineering | Year: 2011

Carbon dioxide (CO2) is considered to be the most important greenhouse gas in terms of overall effect. CO2 geological storage in coal beds is of academic and industrial interest because of economic synergies between greenhouse gas sequestration and coal bed methane (CH4) recovery by displacement/adsorption. Previously, most work focused on either theoretical analyses and mathematical simulations or gas adsorption-desorption experiments using coal particles of millimeter size or smaller. Those studies provided basic understanding of CH4 recovery by CO2 displacement in coal fragments, but more relevant and realistic investigations are still rare. To study the processes more realistically, we conducted experimental CH4 displacement by CO2 and CO2 sequestration with intact 100 × 100 × 200 mm coal specimens. The coal specimen permeability was measured first, and results show that the permeability of the specimen is different for CH4 and CO2; the CO2 permeability was found to be at least two orders of magnitude greater than that for CH4. Simultaneously, a negative exponential relationship between the permeability and the applied mean stress on the specimen was found. Under the experimental stress conditions, 17.5-28.0 volumes CO2 can be stored in one volume of coal, and the displacement ratio CO2-CH4 is as much as 7.0-13.9. The process of injection, adsorption and desorption, displacement, and output of gases proceeds smoothly under an applied constant pressure differential, and the CH 4 content in the output gas amounted to 20-50% at early stages, persisting to 10-16% during the last stage of the experiments. Production rate and CH4 fraction are governed by complex factors including initial CH4 content, the pore and fissure fabric of the coal, the changes in this fabric as the result of differential adsorption of CO2, the applied stress, and so on. During CO2 injection and CH4 displacement, the coal can swell from effects of gas adsorption and desorption, leading to changes in the microstructure of the coal itself. Artificial stimulation (e.g. hydraulic fracturing) to improve coalbed transport properties for either CO2 sequestration or enhanced coal bed methane recovery will be necessary. The interactions of large-scale induced fractures with the fabric at the scale of observable fissures and fractures in the laboratory specimens, as well as to the pore scale processes associated with adsorption and desorption, remain of profound interest and a great challenge. © Springer-Verlag 2011.


Zhang G.,Taiyuan University of Technology | Dong Y.,Taiyuan Heavy Machinery Technical Center | Feng M.,Taiyuan Science and Technology Enducation Center | Zhang Y.,Taiyuan University of Technology | And 2 more authors.
Chemical Engineering Journal | Year: 2010

The CO2 reforming of methane (in coke oven gas) on the coal char catalyst was performed in a fixed bed reactor at temperatures between 800 and 1200 °C under normal pressure. The effects of the coal char catalyst pretreatment and the ratio of CO2/CH4 were studied. Experimental results showed that the coal char was an effective catalyst for production of syngas, and addition of CO2 did not enhance the CH4 reforming to H2. It was also found that the product gas ratio of H2/CO is strongly influenced by the feed ratio of CO2/CH4. The modified coal char catalyst was more active during the CO2-CH4 reforming than the coal char catalyst based on the catalyst volume, furthermore the modified catalyst exhibited high activity in CO2-CH4 reforming to syngas. The conversion of methane can be divided into two stages. In the first stage, the conversion of CH4 gradually decreased. In the second stage, the conversion of methane maintained nearly constant. The conversion of CO2 decreased slightly during the overall reactions in CO2-CH4 reforming. The coal char catalyst is a highly promising catalyst for the CO2 reforming of methane to syngas. © 2009 Elsevier B.V. All rights reserved.


Zhao T.,Taiyuan University of Technology | Wang A.,Taiyuan University of Technology | Wang Y.,Taiyuan University of Technology | Zhang M.,Taiyuan University of Technology | And 3 more authors.
Optics Express | Year: 2013

We propose and experimentally demonstrate a method for fault location in optical communication network. This method utilizes the traffic signal transmitted across the network as probe signal, and then locates the fault by correlation technique. Compared with conventional techniques, our method has a simple structure and low operation expenditure, because no additional device is used, such as light source, modulator and signal generator. The correlation detection in this method overcomes the tradeoff between spatial resolution and measurement range in pulse ranging technique. Moreover, signal extraction process can improve the location result considerably. Experimental results show that we achieve a spatial resolution of 8 cm and detection range of over 23 km with ?8-dBm mean launched power in optical network based on synchronous digital hierarchy protocols. ©2013 Optical Society of America.


Li Y.,Taiyuan University of Technology | Li Y.,AGECON Ltd.
Bulletin of Engineering Geology and the Environment | Year: 2013

The effects of particle shape and size distribution on the constitutive behavior of composite soils with a wide range of particle size were investigated. Two comparable sets of specimens were prepared: (1) mixtures of fines (clay and silt) and an ideal coarse fraction (glass sand and beads), and (2) mixtures of fines and natural coarse fraction (river sand and crushed granite gravels). Direct shear box testing was undertaken on 34 samples and the structure of the shear surfaces, change in volume and water content and the particle shape coefficient of the sheared specimens were examined. The results indicate that the contraction/dilation a specimen exhibits is restrained within the shear zone while the outer zones remain unchanged during shearing. An increased coarse fraction leads to an increase in constant volume shear strength. In addition, increasing elongation or decreasing convexity of the coarse fraction increases the constant volume friction angle. The overall roughness of the shear surface at constant volume state is negatively related to particle smoothness (convexity) and positively related to the area of the shear surface occupied by particles with particular shapes. Two equations are proposed for the estimation of constant volume friction angle based on the proportion and shape coefficient of the coarse fraction. It is hoped this will assist in considering the shear strength of mixed soils when the size of the coarse fraction makes laboratory testing difficult. © 2013 Springer-Verlag Berlin Heidelberg.


Zhu X.,Taiyuan University of Technology | Zhu X.,Huaibei Normal University | Han X.-Q.,Taiyuan University of Technology | Qin W.-P.,Taiyuan University of Technology | And 2 more authors.
Renewable and Sustainable Energy Reviews | Year: 2015

Micro-grids have been developed for over two decades as building blocks for future smart grids. Microgrids have appeared with the advantages such as control flexibility, easy connection of renewable resources, high efficiency and immunity to large area blackouts. Similar to other countries, development of micro-grids in China has gone through from the early stage of AC microgrids to the current varieties of AC, DC and hybrid AC/DC micro-girds based on their applications. Many technical problems have been solved and new problems are continuously appeared during the development process. This paper presents a past, today and future for development of micro-grids in China. The current status of microgrids and renewable energy sources in China is presented first. The topologies of the micro-grids in China are then introduced and classified into three types. Different control techniques of the micro-grids are introduced. Finally, technical challenges and future prospect of micro-grids in China are discussed. © 2014 Elsevier Ltd. All rights reserved.


Zhao J.-J.,Taiyuan University of Technology | Ji G.-H.,Taiyuan University of Technology | Xia Y.,Northwestern Polytechnical University | Zhang X.-L.,Pennsylvania College of Technology
International Journal of Bio-Inspired Computation | Year: 2015

Lung nodule segmentation is an important pre-processing step for analysis of solitary pulmonary nodules in computed tomography (CT) imaging. However, the previous nodule segmentation methods cannot segment the cavitary nodules entirely. To address this problem, an automated segmentation method based on self-generating neural networks and particle swarm optimisation (PSO) is proposed to ensure the integrity of cavitary nodule segmentation. Our segmentation method first roughly segments the image using a general region-growing method. Thereafter, the PSO-self-generating neural forest (SGNF)-based classification algorithm is used to cluster regions. Finally, grey and geometric features are utilised to identify the nodular region. Experimental results show that our method can achieve an average pixel overlap ratio of 88.9% compared with manual segmentation results. Moreover, compared with existing methods, this algorithm has higher segmentation precision and accuracy for cavitary nodules. Copyright © 2015 Inderscience Enterprises Ltd.


Li M.,Taiyuan University of Technology | Chen C.S.,Taiyuan University of Technology | Chen C.S.,University of Southern Mississippi | Karageorghis A.,University of Cyprus
Computers and Mathematics with Applications | Year: 2013

We investigate applications of the method of fundamental solutions (MFS) for the numerical solution of two-dimensional boundary value problems in complex geometries, governed by the Laplace equation and subject to Dirichlet boundary conditions which are not harmonic. Such problems can be very challenging because of the appearance of boundary singularities. We consider several ways of choosing the boundary collocation points as well as the source points in the MFS. We show that with an appropriate such choice the MFS yields highly accurate results. © 2013 Elsevier Ltd. All rights reserved.


Liu L.,Taiyuan University of Technology | Yang J.,Taiyuan University of Technology | Li J.,Taiyuan University of Technology | Dong J.,Taiyuan University of Technology | And 3 more authors.
Angewandte Chemie - International Edition | Year: 2011

Less is more: An open-framework zirconium phosphate with unusual 7-ring channels was synthesized ionothermally from a deep-eutectic solvent. This small-pore material displays a CO2/CH4 adsorption ratio (17.3 at 1 bar) that is significantly higher than that of typical 8-ring materials, making it highly attractive for CO2/CH4 separations. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.


Li H.,Taiyuan University of Technology | Han P.D.,Taiyuan University of Technology | Zhang X.B.,Huaibei Normal University | Li M.,Huaibei Normal University
Materials Chemistry and Physics | Year: 2013

An integrated model based on bond number and bond strength in a system with a cubo-octahedral structure is developed to predict the size-dependent thermal characteristics of nanoparticles. Without any adjustable parameters, this model can be used to predict the melting point and cohesive energy of low-dimensional materials, suggesting that both depend on the size and on the atomic distance. The good agreement of the theoretical prediction with the experimental and molecular dynamic simulation results confirms the validity of the cubo-octahedron in describing the thermodynamic behaviors of nanoparticles even without considering their crystalline structures. © 2012 Elsevier B.V. All rights reserved.


Li X.,Taiyuan University of Technology | Li X.,Simon Fraser University | Weng S.,Simon Fraser University | Ge B.,Biogate Laboratories Ltd. | And 3 more authors.
Lab on a Chip - Miniaturisation for Chemistry and Biology | Year: 2014

A diagnosis platform based entirely on DVD technology was developed for on-site quantitation of molecular analytes of interest, e.g., human chorionic gonadotropin (hCG) in urine samples ("quantitative pregnancy test on a disc"). An hCG-specific monoclonal antibody-binding assay prepared on a regular DVD-R was labeled with nanogold-streptavidin conjugates for signal enhancement with a customized silver-staining protocol. An unmodified, conventional computer optical drive was used for assay reading, and free disc-quality analysis software for data processing. The performance (sensitivity and selectivity) of this DVD assay is comparable to that of well-established colorimetric methods (determination of optical darkness ratios) and standard enzyme-linked immunosorbent assays (ELISA). As validated by examining its linear correlation with the ELISA results on the same set of samples, the DVD assay promises to be a low-cost, multiplex, point-of-care (POC) diagnostic tool for physicians and even for individuals at home, producing prompt results. © 2014 the Partner Organisations.


Li H.,Taiyuan University of Technology | Liang X.H.,Taiyuan University of Technology | Li M.,Huaibei Normal University
Materials Chemistry and Physics | Year: 2014

A new model for the solid melting point Tm(D) from nanovoids is proposed through considering the liquid layer growth behavior. This model, which does not have any adjustable parameter, introduces the classical thermodynamic treatment, i.e., the liquid nucleation and growth theory, for nanoparticle melting. With increased void diameter D, Tm(D) approaches to T m0. Moreover, Tm(D) > Tm0 for a small void (Tm0 is the bulk melting point). In other words, the solid can be significantly superheated especially when D decreases, even if the difference of interface energy is larger than zero. This finding can be expected from the negatively curved surface of the void. The model predictions are consistent with the molecular dynamic (MD) simulation results for argon solids. Moreover, the growth of liquid layer from void surface relies on both size and temperature, which directly determine liquid layer thickness, and only when liquid layer thickness reaches to a critical value, can void become instable. © 2014 Elsevier B.V. All rights reserved.


Guo R.,Taiyuan University of Technology | Liu Y.-F.,Taiyuan University of Technology | Hao H.-Q.,Taiyuan University of Technology | Qi F.-H.,Beijing Wuzi University
Nonlinear Dynamics | Year: 2015

Under investigation in this paper is a coherently coupled nonlinear Schrödinger system which describes the propagation of polarized optical waves in an isotropic medium. By virtue of the Darboux transformation, some new solutions have been generated on the vanishing and non-vanishing backgrounds, including multi-solitons, bound solitons, one-breathers, bound breathers, two-breathers, first-order and higher-order rogue waves. Dynamic behaviors of those solitons, breathers and rogue waves have been discussed through graphic simulation. © 2015, Springer Science+Business Media Dordrecht.


Wang Z.,Taiyuan University of Technology | Hao X.,Taiyuan University of Technology | Zhang Z.,Taiyuan University of Technology | Liu S.,Taiyuan University of Technology | And 2 more authors.
Sensors and Actuators, B: Chemical | Year: 2012

Unipolar pulse waveforms consist of an applied anode potential during the on-period and an open-circuit potential during the off-period. Unipolar pulse electrodeposition (UPED) was used to fabricate nickel hexacyanoferrate/chitosan/ carbon nanotubes (NiHCF/CS/CNTs) nanocomposite films with controllable structure on the electrode surface of a hydrogen peroxide (H 2O 2) sensor. One-step electrodeposition of NiHCF/CS/CNTs film with insoluble-structure NiHCF nanoparticles was performed, and the whole procedure took only several minutes. The morphology and the composition of the NiHCF/CS/CNTs film were characterized by scanning electron microscopy (SEM) and energy dispersive X-ray (EDS). With the introduction of CNTs, the NiHCF/CS/CNTs system formed showed synergy between CNTs and NiHCF with a significant improvement of redox activity of NiHCF due to the excellent electron-transfer ability of CNTs. Electrochemical experiments revealed that the modified electrode allowed low potential (-0.2 V) detection of H 2O 2 and showed high electrocatalytic activity towards the reduction of H 2O 2. The linear range for the detection of H 2O 2 was 0.04-5.6 mM with a high sensitivity of 654 mA M -1 cm -2 and a rapid response (less than 2 s). The detection limit for H 2O 2 was as low as 2.8 × 10 -7 M (S/N = 3). © 2012 Elsevier B.V. All rights reserved.


Wang Z.,Taiyuan University of Technology | Sun S.,Taiyuan University of Technology | Hao X.,Taiyuan University of Technology | Ma X.,Taiyuan University of Technology | And 3 more authors.
Sensors and Actuators, B: Chemical | Year: 2012

Electroactive hybrid films with cubic nickel hexacyanoferrate/polyaniline (NiHCF/PANI) were synthesized on carbon nanotubes (CNTs) modified platinum electrodes by a facile one-step electrosynthesis method using cyclic voltammetry (CV). The morphologies and structures of the as-prepared NiHCF/PANI/CNTs films were characterized using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR), respectively. Due to the introduction of CNTs with carboxyl groups, an acidic micro-environment was provided for the nitrogen atoms in the PANI chains, which could maintain its electroactivity in neutral aqueous solutions. The hybrid films were applied for hydrogen peroxide (H 2O 2) detection and showed synergy and higher electrocatalytic activity with a higher sensitivity, a faster response time and a lower detection limit. It was found that detection sensitivity could be regulated by controlling the time of CV of electrosynthesis during the preparation of the hybrid film. A catalytic rate constant of 1.29 × 10 8 cm 3 mol -1 s -1 was obtained from an investigation of the kinetics of the catalytic reaction. SEM images showed that the cubic composite nano-particles of PANI and NiHCF were formed and distributed uniformly on the CNTs. The hybrid film prepared had good stability and reproducibility in the detection of H 2O 2, and should be useful in practical H 2O 2 sensors. © 2012 Elsevier B.V. All rights reserved.


Du X.,Taiyuan University of Technology | Zhang H.,Taiyuan University of Technology | Hao X.,Taiyuan University of Technology | Guan G.,Hirosaki University | Abudula A.,Hirosaki University
ACS Applied Materials and Interfaces | Year: 2014

A facile unipolar pulse electropolymerization (UPEP) technique is successfully applied for the preparation of ion-imprinted composite film composed of ferricyanide-embedded conductive polypyrrole (FCN/PPy) for the selective electrochemical removal of heavy metal ions from wastewater. The imprinted heavy metal ions are found to be easily removed in situ from the growing film only by tactfully applying potential oscillation due to the unstable coordination of FCN to the imprinted ions. The obtained Ni2+ ion-imprinted FCN/PPy composite film shows fast uptake/release ability for the removal of Ni2+ ions from aqueous solution, and the adsorption equilibrium time is less than 50 s. The ion exchange capacity reaches 1.298 mmol g-1 and retains 93.5% of its initial value even after 1000 uptake/release cycles. Separation factors of 6.3, 5.6, and 6.2 for Ni 2+/Ca2+, Ni2+/K+, and Ni 2+/Na+, respectively, are obtained. These characteristics are attributed to the high identification capability of the ion-imprinted composite film for the target ions and the dual driving forces resulting from both PPy and FCN during the redox process. It is expected that the present method can be used for simple preparation of other ion-imprinted composite films for the separation and recovery of target heavy metal ions as well. © 2014 American Chemical Society.


Kaewpanha M.,Hirosaki University | Guan G.,Hirosaki University | Hao X.,Taiyuan University of Technology | Wang Z.,Taiyuan University of Technology | And 3 more authors.
Fuel Processing Technology | Year: 2014

Alkali and alkaline earth species in biomass have self-catalytic activity on the steam gasification to produce hydrogen-rich gas. In this study, three types of biomass, i.e., brown seaweed, Japanese cedar, apple branch containing different concentrations of alkali and alkaline earth species, and the mix of both of them were gasified with steam in a fixed-bed reactor under atmospheric pressure. The effects of reaction temperature, steam amount and mixing ratio in co-gasification on gas production yields were investigated. The results showed that higher gas production yields (especially for H2 and CO 2) were obtained when the brown seaweed was used than the other two types of biomass since the ash content in brown seaweed was much higher than in land-based biomass and contained a large amount of alkali and alkaline earth species. The yield of hydrogen increased with an increase in the amount of steam, but excessive steam use reduced the hydrogen production yield. From the co-gasification experiments, the gas production yields (especially for H 2 and CO2) from the land-based biomass increased with the increase in brown seaweed ratio, suggesting that the alkali and alkaline earth species in brown seaweed acted as the catalysts to enhance the gasification of land-based biomass in co-gasification process. © 2013 Elsevier B.V.


Liu S.-D.,Taiyuan University of Technology | Liu S.-D.,Wuhan University | Yang Z.,Taiyuan University of Technology | Liu R.-P.,Taiyuan University of Technology | Li X.-Y.,Taiyuan University of Technology
Journal of Physical Chemistry C | Year: 2011

Practical implementations of biosensing with metallic nanostructures often suffer from the large line width of the plasmon resonances induced by large radiative damping. A double split nanoring cavity is designed to suppress the radiative damping. The coupling between the superradiant quadrupole mode of a split nanoring with one gap and the subradiant quadrupole mode of a split nanoring with two gaps leads to splitting of the modal energies into bonding and antibonding quadrupole-quadrupole modes. The radiative damping is suppressed effectively, leading to a narrow line width for both bonding and antibonding quadrupole-quadrupole modes. Calculation results show that bulk refractive index sensitivities exceeding 1200 nm/RIUwith a figure of merit exceeding 8.5 in the near-infrared are obtained with a Au double split nanoring cavity. The large cavity volumes and uniform electric fields inside the cavity make the double split nanoring cavity a good platform for surface-enhanced molecular sensing. © 2011 American Chemical Society.


Liu S.-D.,Taiyuan University of Technology | Liu S.-D.,Wuhan University | Yang Z.,Taiyuan University of Technology | Liu R.-P.,Taiyuan University of Technology | Li X.-Y.,Taiyuan University of Technology
ACS Nano | Year: 2012

Fano resonances in plasmonic nanostructures are important for plasmon line shaping. Compared to a single Fano resonance, multiple Fano resonances can modify plasmon lines at several spectral positions simultaneously, but they often suffer from weak modulation depths. In this paper, plasmonic heptamer clusters comprising split nanorings are designed to form multiple Fano resonances. Three prominent Fano resonances are observed in the spectra due to the formation of multiple narrow subradiant resonances, and the multiple Fano resonances can be switched on and off by adjusting the polarization direction. Particularly, by modifying the geometry parameters, there is a large tunability of the modulation depth of each Fano resonance. Heptamer clusters comprising split nanorings are highly suitable for plasmon line shaping, and it is expected that they are useful for multiwavelength biosensing and surface-enhanced Raman scattering. © 2012 American Chemical Society.


Wang Z.,Taiyuan University of Technology | Wang Y.,Taiyuan University of Technology | Hao X.,Taiyuan University of Technology | Liu S.,Taiyuan University of Technology | And 2 more authors.
Electrochimica Acta | Year: 2013

An all cis-polyaniline nanotube film was successfully prepared using a novel unipolar pulse electro-polymerization method and its formation mechanism was analyzed and discussed. Due to its unique chemical molecular conformation, many excellent performances such as low charge transfer resistance, good water wettability, high apparent diffusion coefficient, large redox site capacity and super-stability were identified. When it was applied for the supercapacitor electrode, a high specific capacitance of 1007.7 F g-1 with a dramatic retention life of 99% after 2000 charge/discharge cycles was obtained. The ascorbic acid sensor fabricated by this film showed a large linear range for the detection of ascorbic acid between 1.0 × 10-6 and 1 × 10-2 M with a high sensitivity of 182 mA M-1 cm-1. © 2013 Elsevier Ltd. All rights reserved.


Zhang R.,Taiyuan University of Technology | Liu H.,Taiyuan University of Technology | Liu H.,Shanxi Datong University | Li J.,Taiyuan University of Technology | And 2 more authors.
Applied Surface Science | Year: 2012

The interaction mechanism of H 2S with different Cu 2O(1 1 1) surfaces, including perfect, oxygen-vacancy and sulfur-containing surfaces, have been systematically studied using periodic density functional calculations. Different kinds of possible modes of H 2S, as well as the resultant SH and S species adsorbed on these surfaces are identified. Two types of pathways via molecular and dissociative adsorption processes are mapped out. Our results show that sulfur species (H 2S, SH and S) interact with surface Cu centers; H 2S exists in the form of molecular adsorption on perfect and sulfur-containing surfaces; the dissociative adsorption of H 2S occurs predominantly on oxygen-vacancy surface, suggesting that oxygen-vacancy exhibits a strong catalytic activity toward the dissociation of H 2S. On the other hand, the dissociation processes of the molecular and dissociative adsorption H 2S, leading to final product S species on these Cu 2O(1 1 1) surfaces, show that the overall dissociation process is exothermic. Meanwhile, with respect to molecular adsorption H 2S, the activation barrier and reaction energy of the overall dissociation process on perfect and oxygen-vacancy surfaces indicate that H 2S can easily dissociate into S species. Importantly, in the case of dissociative adsorption of H 2S, the dissociation of H 2S into S species is a spontaneous process with respect to molecular adsorption H 2S. However, on sulfur-containing surface, the presence of surface S atom goes against the HS bond-breaking process both thermodynamically and kinetically. Finally, the vibrational frequencies for the adsorbed H 2S, SH and S species on these surfaces have been obtained, which can be applied to guide surface vibrational spectroscopy in experiment. © 2012 Elsevier B.V.


Zhang Y.,Henan University of Science and Technology | Zhang Y.,Nanjing University | Hou Y.,Xi'an Jiaotong University | Jia H.,Taiyuan University of Technology
Computers and Mathematics with Applications | Year: 2014

In this paper, we consider a subgrid stabilized defect-correction method for the steady-state natural convection problem. We state the stabilities and error results for the defect step and the first correction step of the defect correction method. The derived theoretical results are supported by several numerical examples. © 2013 Elsevier Ltd. All rights reserved.


Wei Z..-Z.,Tianjin Environmental Engineering Assessment Center | Li D..-C.,Taiyuan University of Technology | Pang X..-Y.,Taiyuan University of Technology | Lv C..-Q.,Shanxi Datong University | And 2 more authors.
ChemCatChem | Year: 2012

CO oxidation on the IB group metals [Cu(111), Ag(111), and Au(111)] and corresponding metal oxides [Cu 2O(100), Ag 2O(100), and Au 2O(100)] has been studied by means of density functional theory calculations with the aim to shed light on the reaction mechanism and catalytic activity of metals and metal oxides. The calculated results show that 1)the molecular oxygen mechanism is favored on Ag(111) and Au(111), but the atomic oxygen mechanism is favored on Cu(111); 2)the metal-terminated metal oxide shows very low activity for CO oxidation; 3)the lattice oxygen can react either with gas phase CO or the absorbed CO molecule on oxygen-terminated metal oxides; and 4)the reaction barrier for CO oxidation follows the order of M 2O(100)-O


He L.L.,China Academy of Engineering Physics | Chen X.W.,China Academy of Engineering Physics | Wang Z.H.,Taiyuan University of Technology
International Journal of Impact Engineering | Year: 2016

Two-group penetration tests of Concept Projectile for High-speed Penetration (CPHP) are carried out with striking velocity ranging from 1130 m/s to 1650 m/s. Almost all projectiles are integral after penetration except the one at striking velocity 1650 m/s. The maximum dimensionless Depth of Penetration (DOP) reaches 78.9 at striking velocity 1415 m/s with the concrete strength as 33.4 MPa. It further confirms that CPHP has excellent structural stability and penetration performance into concrete target at high striking velocities. The penetration performances of CPHP made of different materials are also compared. It indicates that the strength and ductility of material jointly control the penetration performance of CPHP. The mass loss of CPHP distributes not only in its nose but also in its shank. The CPHP nose still keeps ogival and the surface of CPHP shank recedes inward. Furthermore, the mass loss mechanism is studied by metallographic observation. It indicates that the heat transformed from frictional work between target and projectile is the main cause of Heat Affected Zone (HAZ), and the peeling of molten surface layer is the main cause of mass loss. Several White Narrow Bands (WNBs) in CPHP nose tip contribute minor mass loss due to its rare number and limited dimensions. Finally, the analytical model for DOP of CPHP was derived. The model prediction is validated by the available experimental result. © 2016 Elsevier Ltd. All rights reserved.


Luo H.,Shanxi Datong University | Shen J.,Taiyuan University of Technology | Zhang C.,Taiyuan University of Technology
Composites Part B: Engineering | Year: 2013

The Li0.35Zn0.3Fe2.35O4 micro-belts were prepared by cotton template method. The nickel-coated carbon fibers were obtained by electroless plating method. The formation mechanism of the ferrite micro-belt was studied. The microwave absorption properties of the Li0.35Zn0.3Fe2.35O4 micro-belts/nickel-coated carbon fibers composites were investigated in the frequency range of 30-6000 MHz. The absorbers of the Li0.35Zn 0.3Fe2.35O4 micro-belts/nickel-coated carbon fibers composites have much better microwave absorption properties than the nickel-coated carbon fibers absorbers, and the microwave absorption properties of the composites are influenced by the thickness of the absorber. © 2013 Elsevier Ltd. All rights reserved.


Whittaker P.B.,University of Western Australia | Wang X.,University of Tasmania | Regenauer-Lieb K.,University of Western Australia | Chua H.T.,University of Western Australia | Chua H.T.,Taiyuan University of Technology
Physical Chemistry Chemical Physics | Year: 2013

A method for predicting the isosteric heat of gas adsorption on solid materials is developed which requires the measurement of a single isotherm - where previous methods, such as the Clausius-Clapeyron approach, require either multiple isotherms or complex calorimetric measurement. The Tóth potential function, stemming from the Polanyi potential function, is evaluated using the Langmuir and Tóth isotherm equations to generate new equations for the isosteric heat. These new isosteric heat equations share common parameters with the isotherm equations and are determined from isotherm fitting. This method is demonstrated in the literature for gas adsorption onto solid adsorbates including zeolites of various surface charge character and non-porous rutile phase titanium dioxide. Predictions are made using the new isosteric heat equations and then compared to calorimetric data. © the Owner Societies 2013.


Pang X.-Y.,Taiyuan University of Technology | Liu C.,Nankai University | Li D.-C.,Taiyuan University of Technology | Lv C.-Q.,Shanxi Datong University | And 2 more authors.
ChemPhysChem | Year: 2013

The reaction mechanism of CO oxidation on the Co3O4 (110) and Co3O4 (111) surfaces is investigated by means of spin-polarized density functional theory (DFT) within the GGA+U framework. Adsorption situation and complete reaction cycles for CO oxidation are clarified. The results indicate that 1) the U value can affect the calculated energetic result significantly, not only the absolute adsorption energy but also the trend in adsorption energy; 2) CO can directly react with surface lattice oxygen atoms (O2f/O3f) to form CO2 via the Mars-van Krevelen reaction mechanism on both (110)-B and (111)-B; 3) pre-adsorbed molecular O2 can enhance CO oxidation through the channel in which it directly reacts with molecular CO to form CO2 [O2(a)+CO(g)→CO2(g)+O(a)] on (110)-A/(111)-A; 4) CO oxidation is a structure-sensitive reaction, and the activation energy of CO oxidation follows the order of Co3O4 (111)-A(0.78 eV)>Co3O4 (111)-B (0.68 eV)>Co3O 4 (110)-A (0.51 eV)>Co3O4 (110)-B (0.41 eV), that is, the (110) surface shows higher reactivity for CO oxidation than the (111) surface; 5) in addition to the O2f, it was also found that Co3+ is more active than Co2+, so both O2f and Co3+ control the catalytic activity of CO oxidation on Co 3O4, as opposed to a previous DFT study which concluded that either Co3+ or O2f is the active site. Different mechanisms of CO oxidation depending on the surface structure of Co 3O4 are found by DFT calculations, which also show that CO oxidation on Co3O4 (110)-B has higher activity than that on Co3O4(111)-B (see reaction energy profiles in the picture), that is, it is a structure sensitive reaction. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Hou J.,Shanxi University | Hou J.,Taiyuan University of Technology | Guo Y.,Shanxi University | Guo Y.,Shanxi Datong University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2010

The question of under what conditions different witnesses (e.g., W 1,W 2) may detect some common entangled states [i.e., there exists some state ρ so that Tr(W 1ρ) < 0andTr(W 2ρ) < 0] is answered for both finite-dimensional and infinite-dimensional bipartite systems. Finitely many different witnesses W 1,W 2,...,W n can detect some common entangled states if and only if ∑ n i=1 d iW i is still a witness for any nonnegative numbers d 1,d 2,...,d n with∑ n i=1 d i = 1; they cannot detect any common entangled state if and only if ∑ n i=1 c iW i is a positive operator for some nonnegative numbers c 1,c 2,...,c n with ∑ n i=1 c i = 1. For two witnesses W 1 and W 2 more can be said. First, W 1 and W 2 can detect the same set of entangled states if and only if W 1 = aW 2 for some number a > 0. Second, W 2 can detect more entangled states than W 1 can if and only if W 1 = aW 2 + D for some numbera > 0 and a positive operator D. As an application, some characterizations of the optimal witnesses are given and some structural properties of the decomposable optimal witnesses are presented. © 2010 The American Physical Society.


Sun B.,Taiyuan University of Technology | Hao X.-G.,Taiyuan University of Technology | Wang Z.-D.,Taiyuan University of Technology | Guan G.-Q.,Hirosaki University | And 3 more authors.
Journal of Hazardous Materials | Year: 2012

A series of experiments were performed to evaluate the continuous separation of cesium based on an electrochemically switched ion exchange (ESIX) process using a diaphragm-isolated reactor with two identical nickel hexacyanoferrate/porous three-dimensional carbon felt (NiHCF/PTCF) electrodes as working electrodes. The effects of applied potential, initial concentrations and pH values of the simulation solutions on the adsorption of cesium ion were investigated. The adsorption rate of cesium ion in the ESIX process was fitted by a pseudo-first-order reaction model. The experiments revealed that the introduction of applied potential on the electrodes greatly enhanced the adsorption/desorption rate of Cs+ and increased the separation efficiency. H3O+ was found to play a dual role of electrolyte and competitor, and the adsorption rate constant showed a curve diversification with an increase in pH value. Also, it was found that the electrochemically switched adsorption process of Cs+ by NiHCF/PTCF electrodes proceeded in two main steps, i.e., an ESIX step with a fast adsorption rate and an ion diffusion step with a slow diffusion rate. Meanwhile, the NiHCF/PTCF film electrode showed adsorption selectivity for Cs+ in preference to Na+. © 2012 Elsevier B.V.


Ma N.,Taiyuan University of Technology | Ma N.,Xi'an Jiaotong University | Zhang S.,Xi'an Jiaotong University | Liu D.,Changzhou University | Wang V.,Xi'an University of Technology
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2014

Recent theoretical works have predicated the appearance of Weiss oscillations in the magnetoconductivity with a one-dimensional periodic electrical or magnetic modulation in graphene. This paper further explores the electrostatic field effect on the Weiss oscillations in the presence of crossed uniform in-plane electric field and perpendicular magnetic field that is weakly and periodically modulated along one direction. We find that the oscillation amplitude (OA) of Weiss oscillations and the value of conductivity are both shown to increase as the electric field E increases for a given magnetic field B. More interestingly, the electric field leads to an abrupt disappearance of the Weiss oscillations, when the value of electric to magnetic field ratio approaches a threshold value, i.e., γe = E/υFB = 1. These phenomena, not known in the conventional 2D electron gas, are a consequence of the anomalous spectrum of electron in graphene. © 2014 Elsevier B.V. All rights reserved.


Guo Y.,Shanxi Datong University | Guo Y.,Taiyuan University of Technology
International Journal of Modern Physics B | Year: 2013

Measurement-induced nonlocality (MIN), introduced by Luo and Fu [Phys. Rev. Lett. 106, 120401 (2011)], is a kind of quantum correlation which is different from entanglement and quantum discord (QD). MIN is defined over one-sided projective measurements. In this paper, we introduce a MIN over two-sided projective measurements. The nullity of this two-sided MIN is characterized, a formula for calculating two-sided MIN for pure states is proposed, and a lower bound of (two-sided) MIN for maximally entangled mixed states is given. In addition, we find that (two-sided) MIN is not continuous. Both finite- and infinite-dimensional cases are considered. © 2013 World Scientific Publishing Company.


Liu S.-D.,Taiyuan University of Technology | Liu S.-D.,Wuhan University | Zhang M.-J.,Taiyuan University of Technology | Wang W.-J.,Taiyuan University of Technology | Wang Y.-C.,Taiyuan University of Technology
Applied Physics Letters | Year: 2013

Multiple Fano resonances in plasmonic pentamer clusters composed of nanorings are observed and investigated. Molecular point group theory is used to understand the formation of multiple Fano resonances. By modifying the radius of the center ring or the angle between the center and the surrounding rings, the modulation depths and the spectral positions of the multiple Fano resonances can be tuned within a wide range. For pentamers composed of split nanorings, another Fano resonance can be excited because of the excitation of the quadrupole mode of the surrounding split nanorings. © 2013 American Institute of Physics.


Liu S.-D.,Taiyuan University of Technology | Liu S.-D.,Wuhan University | Yang Z.,Taiyuan University of Technology | Liu R.-P.,Taiyuan University of Technology | Li X.-Y.,Taiyuan University of Technology
Optics Express | Year: 2011

Plasmonic-induced optical transparency with double split nanoring cavity is investigated with finite difference time domain method. The coupling between the bright third-order mode of split nanoring with one gap and the dark quadrupole mode of split nanoring with two gaps leads to plasmonic analogue of electromagnetically induced transparency. The transparence window is easily modified to the near-infrared and visible range. Numerical results show a group index of 16 with transmission exceeding 0.76 is achieved for double split nanoring cavity. There is large cavity volume of double split nanoring, and the field enhancement inside the cavity is homogenous. Double split nanoring cavity could be a good platform for slow light and sensing applications. © 2011 Optical Society of America.


Ma Y.,Hirosaki University | Guan G.,Hirosaki University | Phanthong P.,Hirosaki University | Hao X.,Taiyuan University of Technology | And 4 more authors.
Journal of Physical Chemistry C | Year: 2014

Molybdenum carbides were modified by nickel with different doping amounts by using a temperature-programmed reaction (TPRe) process and used for steam reforming of methanol (SRM). XRD analysis results indicated that the β-Mo2C phase was easily formed in Ni-modified carbide samples. The doping amount of Ni had great effect not only on the activity of the molybdenum carbide catalyst, but also on the catalyst stability. For relatively lower Ni doping amounts, i.e., Ni/Mo molar ratio = 0.8/99.2 to 2.4/97.6, the catalysts exhibited almost the same methanol conversion in the reaction temperature range. Meanwhile, when the Ni/Mo molar ratio was over 5/95, the catalytic activity was decreased greatly. Furthermore, Ni-Mo2C with Ni/Mo molar ratios of 1.6/98.4 and 2.4/97.6 showed longer term stability than other samples. Compared with the pure β-Mo2C and other iron group element modified carbide samples, the Ni-modified one showed higher catalytic activity and stability. The fresh and spent catalysts were characterized by XRD, XPS, BET, and TEM and it is found that the resistance to the oxidation of molybdenum carbide and carbon deposition could be enhanced by the loading of Ni with low amounts. © 2014 American Chemical Society.


Gao A.,Taiyuan University of Technology | Hang R.,Taiyuan University of Technology | Huang X.,Taiyuan University of Technology | Zhao L.,PLA Fourth Military Medical University | And 5 more authors.
Biomaterials | Year: 2014

A versatile strategy to endow biomaterials with long-term antibacterial ability without compromising the cytocompatibility is highly desirable to combat biomaterial related infection. TiO2 nanotube (NT) arrays can significantly enhance the functions of many cell types including osteoblasts thus having promising applications in orthopedics, orthodontics, as well as other biomedical fields. In this study, TiO2 NT arrays with Ag2O nanoparticle embedded in the nanotube wall (NT-Ag2O arrays) are prepared on titanium (Ti) by TiAg magnetron sputtering and anodization. Well-defined NT arrays containing Ag concentrations in a wide range from 0 to 15 at % are formed. Ag incorporation has little influence on the NT diameter, but significantly decreases the tube length. Crystallized Ag2O nanoparticles with diameters ranging from 5nm to 20nm are embedded in the amorphous TiO2 nanotube wall and this unique structure leads to controlled release of Ag+ that generates adequate antibacterial activity without showing cytotoxicity. The NT-Ag2O arrays can effectively kill Escherichia coli and Staphylococcus aureus even after immersion for 28 days, demonstrating the long lasting antibacterial ability. Furthermore, the NT-Ag2O arrays have no appreciable influence on the osteoblast viability, proliferation, and differentiation compared to the Ag free TiO2 NT arrays. Ag incorporation even shows some favorable effects on promoting cell spreading. The technique reported here is a versatile approach to develop biomedical coatings with different functions. © 2014 Elsevier Ltd.


Guo Y.,Shanxi Datong University | Guo Y.,Taiyuan University of Technology | Hou J.,Taiyuan University of Technology
Journal of Physics A: Mathematical and Theoretical | Year: 2013

Measurement-induced nonlocality is a measure of nonlocality introduced recently by Luo and Fu. We present here sufficient and necessary conditions for a quantum state for which this quantity is equal to zero. Furthermore it is shown that for such a state ρab with any local channel acting on Ha cannot create measurement-induced nonlocality if and only if either it is a completely contractive channel or it is a nontrivial isotropic channel. For the qubit case this property is an additional characteristic of the completely contractive channel or the commutativity-preserving unital channel. © 2013 IOP Publishing Ltd.


Guo Y.,Shanxi Datong University | Guo Y.,Taiyuan University of Technology | Hou J.,Taiyuan University of Technology
Reports on Mathematical Physics | Year: 2013

The realignment operation and the computable cross norm or realignment (CCNR) criterion of separability for states in infinite-dimensional bipartite quantum systems are established. Let HA and HB be complex Hilbert spaces with dim HA ⊕ HB ≤ +∞. Let ρ be a quantum state acting on HA ⊕ HB and {δk} be the Schmidt coefficients of ρ as a vector in the Hilbert space C2(HA) ⊕ C2(HB). We introduce the realignment operator ρR and the computable cross norm ||ρ||CCN of ρ and show that if ρ is separable, then ||ρR||Tr = ||ρ||CCN = σk δ ≤ 1. In particular, if ρ is a pure state, then ρ is separable if and only if ||ρR||Tr = ||ρ||CCN = σk δk = 1. For the finite-dimensional case, this recovers the original computable cross norm criterion. © 2013 Polish Scientific Publishers.


Guo Y.,Shanxi Datong University | Guo Y.,Taiyuan University of Technology | Hou J.,Taiyuan University of Technology
Journal of Physics A: Mathematical and Theoretical | Year: 2013

Quantum discord (QD) is one of the main quantum correlations in quantum information theory. In this paper, we show that a local channel cannot create QD for zero QD states of size d 3 if and only if either it is a completely decohering channel or it is a nontrivial isotropic channel. For the qubit case this property is an additional characteristic of the completely decohering channel or the commutativity-preserving unital channel. In particular, the exact forms of the completely decohering channel and the commutativity-preserving unital qubit channel are proposed. Consequently, our results confirm and improve the conjecture proposed by Hu et al for the case of d 3 and improve the result proposed by Streltsov et al for the qubit case. © 2013 IOP Publishing Ltd.


Wang L.,North China Electrical Power University | Zhu Y.-J.,North China Electrical Power University | Qi F.-H.,Beijing Wuzi University | Li M.,North China Electrical Power University | Guo R.,Taiyuan University of Technology
Chaos | Year: 2015

In this paper, the nonautonomous Lenells-Fokas (LF) model is investigated. The modulational instability analysis of the solutions with variable coefficients in the presence of a small perturbation is studied. Higher-order soliton, breather, earthwormon, and rogue wave solutions of the nonautonomous LF model are derived via the n-fold variable-coefficient Darboux transformation. The solitons and earthwormons display the elastic collisions. It is found that the nonautonomous LF model admits the higher-order periodic rogue waves, composite rogue waves (rogue wave pair), and oscillating rogue waves, whose dynamics can be controlled by the inhomogeneous nonlinear parameters. Based on the second-order rogue wave, a diamond structure consisting of four first-order rogue waves is observed. In addition, the semirational solutions (the mixed rational-exponential solutions) of the nonautonomous LF model are obtained, which can be used to describe the interactions between the rogue waves and breathers. Our results could be helpful for the design of experiments in the optical fiber communications. © 2015 AIP Publishing LLC.


Liu S.-D.,Taiyuan University of Technology | Liu S.-D.,Wuhan University | Yang Z.,Taiyuan University of Technology | Liu R.-P.,Taiyuan University of Technology | Li X.-Y.,Taiyuan University of Technology
Applied Physics Letters | Year: 2012

Radiative damping and refractive index sensing performances of elliptical split nanorings are investigated. The third order resonance can be viewed as two electric dipoles in opposite directions, leading to a cancellation of their dipole moments. The scattering quantum yield decreases from 0.647 to 0.183 by adjusting the outer radii, and the corresponding largest figure of merit of sensing performance is 10.6, which is 61% and 86% larger than the split and perfect rings, respectively. Radiative damping can be further suppressed by increasing the gap size; the scattering quantum yield is decreased to 0.138 when the gap size is 35 nm. © 2012 American Institute of Physics.


Guo Y.,Shanxi Datong University | Guo Y.,Taiyuan University of Technology | Hou J.,Taiyuan University of Technology
Journal of Physics A: Mathematical and Theoretical | Year: 2012

We present a sufficient condition for a bipartite state to be separable via the strong positive partial transposition structure introduced in Chruściński et al (2008 Phys. Rev. A 77 022113), from which we obtain a class of separable states. In particular, we prove that any classical-quantum state is a state of our class but not vice versa. Both finite- and infinite-dimensional systems are considered. © 2012 IOP Publishing Ltd.


Luo C.,Taiyuan University of Technology | Liang W.,Taiyuan University of Technology | Chen Z.,Taiyuan University of Technology | Zhang J.,Taiyuan University of Technology | And 2 more authors.
Materials Characterization | Year: 2013

Using a two-pass hot rolling process, Al(5052)/Mg(AZ31)/Al(5052) alloy laminated composite plates were fabricated. The first pass was performed at relatively low temperatures, and the second pass was performed at higher temperatures. No new phases formed at the bond interface after the first hot rolling pass. High temperature annealing with the annealing temperature at or above 300 C caused the formation of continuous layers of the intermetallics Mg17Al12 and Al3Mg2 at the bond interface of Al(5052)/Mg(AZ31). The growth rate of the intermetallic layers increased with increasing the annealing temperature, while the incubation time decreased with increasing the temperature. A kinetic equation was developed to describe the growth of the intermetallic compound layers. The second hot rolling pass caused the break of the continuous intermetallic layers into fragments, which were intermittently dispersed at the bond interface. © 2013 Elsevier Inc.


Liu Z.,Taiyuan University of Technology | Wang Y.,Beijing Institute of Technology | Li J.,Taiyuan University of Technology | Zhang R.,Taiyuan University of Technology
RSC Advances | Year: 2014

Using recent well-defined models of γ-Al2O3 surfaces, the interactions of Nin(n = 1-7) clusters with different γ-Al2O3 surfaces have been investigated in order to illustrate, by density functional theory periodic calculations, the effect of γ-Al2O3 surface hydroxylation on the stability and nucleation of Ni in Ni/γ-Al2O3 catalyst. Three types of γ-Al2O3 surfaces, dehydrated γ-Al 2O3(100), dehydrated γ-Al2O 3(110) and hydrated γ-Al2O3(110) were considered. Our results show that for the adsorption of Nin(n = 3-7) clusters, the γ-Al2O3(110) surface is more favorable than the γ-Al2O3(100) surface, however, for single Ni atoms and Ni2 clusters, the reverse becomes true. Meanwhile, for the adsorption of Nin(n = 2-7) clusters, the hydrated (110) surface is not favorable compared to the dehydrated (110) surface, due to the presence of surface hydroxyls on the former. The reverse is true for single Ni atoms due to weaker surface deformation. Further, the support stabilizes Nin(n = 2-7) clusters well in the supported state, in which the presence of surface hydroxyls reduces the stability of the supported Nin clusters. On the other hand, the nucleation ability of Nin clusters on different γ-Al2O3 surfaces, is more favorable on the γ-Al2O3(110) surface than on the γ-Al 2O3(100) surface, and the dehydrated (110) surface is more favorable than the hydrated (110) surface due to the presence of surface hydroxyls, namely, surface hydroxylation reduces the nucleation ability of Nin clusters on the γ-Al2O3 surface. More importantly, the exothermicity of supported Nin(n = 2-7) clusters on different γ-Al2O3 surfaces is lower than that of isolated Nin clusters, indicating that the support is not favorable for the nucleation of Nin(n = 2-7) clusters, as a result, the support can inhibit the aggregation of clusters, and favors the formation of small clusters. This journal is © the Partner Organisations 2014.


Zhang R.,Taiyuan University of Technology | Song L.,Taiyuan University of Technology | Wang Y.,Beijing Institute of Technology
Applied Surface Science | Year: 2012

A density functional theory slab calculations of CH 4 dissociation on Pt(h k l) surfaces have been systematically presented. On the basis of the energetic analysis, the favorable adsorption sites and stable configurations of CH x(x = 0-4) and H species on Pt(1 1 1), Pt(1 1 0) and Pt(1 0 0) surfaces are first obtained, respectively. Afterwards, the most stable configurations of coadsorbed CH x/H(x = 0-3) are located. Further, the kinetic and thermodynamical results of CH 4 dissociation on Pt(h k l) surface suggest that CH is the most abundant CH x species. Our results mean that Pt catalyst can resist the carbon deposition in the CH 4 dissociation, which can give a microscopic reason that why Pt catalyst can lead to lower carbon deposition and show a high activity in the reaction related to CH 4. © 2012 Elsevier B.V.


Liu J.-J.,Taiyuan University of Technology | Wang J.-M.,Beijing Institute of Technology
International Journal of Robust and Nonlinear Control | Year: 2016

In this paper, we are concerned with a cascade of ODE-wave systems with the control actuator-matched disturbance at the boundary of the wave equation. We use the sliding mode control (SMC) technique and the active disturbance rejection control method to overcome the disturbance, respectively. By the SMC approach, the disturbance is supposed to be bounded only. The existence and uniqueness of solution for the closed-loop via SMC are proved, and the monotonicity of the 'reaching condition' is presented without the differentiation of the sliding mode function, for which it may not always exist for the weak solution of the closed-loop system. Considering that the SMC usually requires the large control gain and may exhibit chattering behavior, we then develop an active disturbance rejection control to attenuate the disturbance. The disturbance is canceled in the feedback loop. The closed-loop systems with constant high gain and time-varying high gain are shown respectively to be practically stable and asymptotically stable. Then we continue to consider output feedback stabilization for this coupled ODE-wave system, and we design a variable structure unknown input-type state observer that is shown to be exponentially convergent. The disturbance is estimated through the extended state observer and then canceled in the feedback loop by its approximated value. These enable us to design an observer-based output feedback stabilizing control to this uncertain coupled system. © 2016 John Wiley & Sons, Ltd.


Rahimi B.,University of Western Australia | May J.,University of Western Australia | Regenauer-Lieb K.,University of New South Wales | Chua H.T.,Taiyuan University of Technology | Chua H.T.,University of Western Australia
Desalination | Year: 2015

Two novel desalination processes that utilise low grade sensible heat sources have been modelled and both have been shown to be more thermally efficient means of desalinating water than conventional Multi Effect Distillation (MED). The novel Boosted MED (B-MED) and Flash Boosted MED (FB-MED) processes are capable of higher production rates than conventional MED, enabled by the addition of process components and by an increase in specific electrical power consumption. A simple method of estimating the capital and operational costs of MED, B-MED and FB-MED desalination installations is presented. A generalised comparison of the economics of these three processes is conducted, asserting the economic viability of the novel desalination processes. © 2015 Elsevier B.V.


Yan K.,Taiyuan University of Technology | Yan K.,Lakehead University | Liao J.,Taiyuan University of Technology | Wu X.,Taiyuan University of Technology | Xie X.,Taiyuan University of Technology
RSC Advances | Year: 2013

A Cu-catalyst derived from hydrotalcite precursor was highly selective for the hydrogenation of biomass-derived furfural and levulinic acid. 90% yield of furfuryl alcohol and 51% yield of 2-methylfuran were achieved selectively in the hydrogenation of furfural. 91% yield of γ-valerolactone was achieved in the hydrogenation of levulinic acid. This journal is © 2013 The Royal Society of Chemistry.


Yan K.,Brown University | Yan K.,Taiyuan University of Technology | Lafleur T.,Lakehead University | Wu X.,Taiyuan University of Technology | And 3 more authors.
Chemical Communications | Year: 2015

Cascade upgrading of γ-valerolactone (GVL), produced from renewable cellulosic biomass, with selective conversion to biofuels pentyl valerate (PV) and pentane in one pot using a bifunctional Pd/HY catalyst is described. Excellent catalytic performance (over 99% conversion of GVL, 60.6% yield of PV and 22.9% yield of pentane) was achieved in one step. These biofuels can be targeted for gasoline and jet fuel applications. This journal is © The Royal Society of Chemistry.


Zhang X.,Taiyuan University of Technology | Guo T.,Shanxi Province Industry and Trade College | Wang X.,Taiyuan University of Technology | Wang Y.,Taiyuan University of Technology | And 2 more authors.
Applied Catalysis B: Environmental | Year: 2014

The BiOCl, BiOCl/Bi2O2CO3 composites and Bi2O2CO3 were successfully fabricated by a facile composition-controlled preparation technology at room temperature for the first time. The X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) adsorption isotherm, UV-vis diffuse reflectance spectra (UV-vis DRS) and first-principles methods were employed to characterize the phase structures, morphologies, surface areas, optical properties, and photocatalytic mechanism of as-prepared samples. The BiOCl/Bi2O2CO3 composites exhibited the higher photocatalytic activity than individual BiOCl and Bi2O2CO3 for the degradation of MO under simulated sunlight irradiation. The COD removal efficiency of MO solution over BiOCl/Bi2O2CO3 composite achieved 95% after 8h reaction time. In addition, the formation mechanism and excellent photocatalytic activity of BiOCl/Bi2O2CO3 composite have been investigated and discussed in detail. The enhanced photocatalytic performance of BiOCl/Bi2O2CO3 composites is closely related to the suitable conduction band (CB) interaction and efficient separation of photo-induced electron-hole pairs by the synergistic effect of BiOCl and Bi2O2CO3 under the simulated sunlight irradiation. Combined with the theoretical and experimental findings, the photocatalytic mechanism of BiOCl/Bi2O2CO3 composite and the charge carrier transfer process between Bi2O2CO3 and BiOCl semiconductors have been proposed and investigated. © 2014 Elsevier B.V.


Hu C.,University of Hong Kong | Ting S.-W.,University of Hong Kong | Chan K.-Y.,University of Hong Kong | Huang W.,Taiyuan University of Technology
International Journal of Hydrogen Energy | Year: 2013

The catalytic dehydrogenation of formic acid (HCOOH) on heterogeneous catalysts in aqueous solution to produce CO-free H2 has received intense investigation due to its promising application in portable power devices. In this work, we present a study on the mechanism of HCOOH dehydrogenation on the PtRuBiOx catalyst using density functional theory (DFT) calculations supported by complementary experiments. The catalyst's activity at room temperature was clarified by investigating HCOOH dehydrogenation on PtRu alloy and Bi2O3 surface with a focus on the key reaction steps. The PtRu with different alloying degree was modeled by a four-layer p (2 × 2) unit cell with Pt-skin and leaving Ru atoms in the second and the third layer based on the surface energy and the formation energy. The Bi2O3 surface was represented by the most stable (111) surface of δ-Bi2O3. Based on the computational and experimental results, a reaction pathway for HCOOH dehydrogenation on the PtRuBiOx in aqueous solution was proposed. The results suggest that the promotion of HCOOH dissociation on the Bi 2O3 surface and the ligand effect between Pt and Ru are responsible for the activity of PtRuBiOx toward HCOOH dehydrogenation in aqueous solution at room temperature. Furthermore, the PdBiOx system was also prepared and investigated as a catalyst for HCOOH decomposition at room temperature. The catalytic behavior of PdBiOx for HCOOH dehydrogenation in aqueous solution was compared with that of the PtRuBiO x. Copyright © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.


Yan K.,Lakehead University | Jarvis C.,Lakehead University | Lafleur T.,Lakehead University | Qiao Y.,Max-Planck-Institut für Kohlenforschung | Xie X.,Taiyuan University of Technology
RSC Advances | Year: 2013

Robust Pd nanoparticles were novel and successfully synthesized on the γ-Al2O3 support by a simple and ecofriendly route through the assistance of CO2. The unsupported and supported Pd nanoparticles were initially characterized with a combination of several techniques such as powder X-ray diffraction, energy-dispersion X-ray, X-ray photoelectron spectroscopy and transmission electron microscopy. The face-centered cubic Pd nanoparticles with uniform dispersion were successfully achieved with the Pd loading ranging from 1 wt% to 5 wt%. The resulting Pd nanoparticles (Pd/Al2O3) catalysts were found to be efficient and versatile for the hydrogenation of biomass-derived platform chemicals furfural and levulinic acid under very mild conditions, respectively, showing enhanced catalytic performance. © 2013 The Royal Society of Chemistry.


Li Z.,Xi'an University of Technology | Li Z.,Taiyuan University of Technology | Ma J.,Taiyuan University of Technology
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2012

In order to analyze the flow pattern and the critical Reynolds number of flow pattern conversion to each other in the runner of the labyrinth emitter, the tests of the water flow for the model with five different sizes of runner were conducted, the phenomena of water flow were observed and analyzed, the relationship between the head loss and average velocity in the labyrinth runner was analyzed, and the relationship between friction loss and average velocity along the straight runner that with the same section size as the labyrinth runner was analyzed. The results show that: The labyrinth path has great disturbance on the flow, making the laminar flow change into the transition region when Reynolds number is 41.5; the laminar flow may occur in the labyrinth units at the entrance section which accounts for 10%-12% of the whole labyrinth units. as a whole, the flow pattern can be regarded as turbulence or transition region; unlike the classical Reynolds test, the head loss in the labyrinth path is proportional to the 2.0-2.5th power of average velocity of section; the flow pattern index of labyrinth emitter can be 0.4-0.5; and the critical Reynolds number of flow state conversion between transition region and the turbulence ranges from 87.5 to 125.0 in the test.


Hu C.,University of Hong Kong | Ting S.-W.,University of Hong Kong | Chan K.-Y.,University of Hong Kong | Huang W.,Taiyuan University of Technology
International Journal of Hydrogen Energy | Year: 2012

Formic acid decomposition on noble metals is considered to be a potential method to produce CO-free hydrogen at near ambient temperatures. However, the reaction mechanism, as well as the key points, for HCOOH decomposition on noble metals in aqueous solution remains unclear at microscopic level. In the present work, we employed density functional theory (DFT) calculation to investigate HCOOH decomposition in gas and aqueous phases on four common noble metals (Pt, Pd, Rh, and Au). Based on the present theoretical calculation results and experimental results being available in literature, two reaction pathways were proposed to understand gas- and aqueous-phase HCOOH decomposition on the noble metals. The key points that determine the activities of the metals toward HCOOH decomposition into CO2 and H2 in aqueous solution are clarified. Furthermore, the proposed reaction mechanism can be well extended to interpret the excellent activity of Ag-Pd core-shell bimetallic catalyst for HCOOH decomposition in aqueous solution. It is expected the present reaction mechanisms would enable us to rationally design more active heterogeneous catalysts for HCOOH decomposition into CO-free H2 at relatively low temperatures. Copyright © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.


Yan G.,Taiyuan University of Technology | Zhang Z.,Taiyuan University of Technology | Yan K.,CAS Guangzhou Institute of Energy Conversation | Yan K.,CAS Guangzhou Center for Gas Hydrate Research | Yan K.,University of Chinese Academy of Sciences
Molecular Physics | Year: 2013

To investigate the detailed mechanisms for brown coal oxidation at high temperatures, a ReaxFF reactive forcefield was used to perform a series of molecular dynamics simulations from 1000 K to 2500 K. Analyses indicated that the chemical system tend to be more reactive with increasing temperature. It was found that the oxidation process of brown coal primarily initiates from hydrogen abstraction reactions by O2 and related oxygenated radicals from phenolic hydroxyl groups, methyl groups, especially carboxyl groups in lower temperature to form peroxygen species, or by either thermal decomposition of brown coal backbone in higher temperature. These peroxygen species usually could chemically adsorb on the C-centered radicals of brown coal backbone. The weak O-O bond in peroxygen makes them easier to break into oxygenated radical, which could also chemically adsorb on the C-centred radical to form hydroxyl group and other oxygenated compounds. In the oxidation process of brown coal, the decomposition and oxidation of aliphatic chain is easier than aromatic ring. The chemisorption of peroxygen radical induces the breakage of aromatic ring and accelerates the depth oxidation of brown coal. An increasing number of products are observed with increasing temperature. © 2013 Taylor and Francis.


Wang Z.,Taiyuan University of Technology | Wang Z.,Beijing Institute of Technology | Jing L.,Taiyuan University of Technology | Ning J.,Beijing Institute of Technology | Zhao L.,Taiyuan University of Technology
Composite Structures | Year: 2011

The structural response of dynamically loaded monolithic and sandwich beams made of aluminum skins with different cores is determined by loading the end-clamped beams at mid-span with metal foam projectiles. The sandwich beams comprise aluminum honeycomb cores and closed-cell aluminum foam cores. Laser displacement transducer was used to measure the permanent transverse deflection of the back face mid-point of the beams. The resistance to shock loading is evaluated by the permanent deflection at the mid-span of the beams for a fixed magnitude of applied impulse and mass of beam. It is found that sandwich beams with two kind cores under impact loading can fail in different modes. Experimental results show the sandwich beams with aluminum honeycomb cores present mainly large global deformation, while the foam core sandwich beams tend to local deformation and failure, but all the sandwich beams had a higher shock resistance, then the monolithic beam. For each type of beams, the dependence of transverse deflection upon the magnitude of the applied impulse is measured. Moreover, the effects of face thickness and core thickness on the failure and deformation modes were discussed. Results indicated that the structural response of sandwich beams is sensitive to applied impulse and structural configuration. The experimental results are of worth to optimum design of cellular metallic sandwich structures. © 2010.


Jing L.,Taiyuan University of Technology | Wang Z.,Taiyuan University of Technology | Wang Z.,Beijing Institute of Technology | Ning J.,Beijing Institute of Technology | Zhao L.,Taiyuan University of Technology
Composites Part B: Engineering | Year: 2011

The deformation and failure modes of dynamically loaded sandwich beams made of aluminum skins with open-cell aluminum foam cores were investigated experimentally. The dynamic compressive stress-strain curves of core materials, open-cell aluminum foam, were obtained using Split Hopkinson Pressure Bar. And then the dynamic impact tests were conducted for sandwich beams with open-cell aluminum foam cores. The photographs showing the deflected profiles of the dynamically loaded sandwich beams are exhibited. Several impact deformation modes of sandwich beams can be observed according to contrastive photographs, i.e. large inelastic deformation, face wrinkle and core shear with interfacial failure. A comparison of the measurements is made with analytical predictions, which indicates that the experimentally measured deflections agree well with predictions employing both the inscribing and circumscribing yield loci. For comparison, the quasi-static punching deformation and failure modes of sandwich beams is presented. © 2010 Elsevier Ltd. All rights reserved.


Yan K.,Lakehead University | Lafleur T.,Lakehead University | Wu G.,Lakehead University | Liao J.,Tianjin University | And 2 more authors.
Applied Catalysis A: General | Year: 2013

A series of Pd nanoparticles deposited on the SiO2 support were facilely and successfully synthesized in the presence of the green solvent CO2, where the uniform distribution of Pd with small particle size was successfully achieved. The resulting Pd/SiO2 nanoparticles catalysts exhibited excellent catalytic performances in the selective hydrogenation of biomass-derived levulinic acid, showing close to perfect selectivity of biofuel γ-valerolactone with the TON of 884.7 at 97.3% conversion of levulinic acid. The catalytic performance was superior to the activities of the 5 wt% Pd/SiO2 nanoparticle catalyst prepared by the traditional impregnation method. Besides, the reaction parameters (e.g., the Pd loading, reaction time, reaction temperature, and hydrogen pressure), catalyst stability and reaction mechanism on the hydrogenation performance were studied. The resulting Pd nanoparticles catalysts behaved high stability in the hydrogenation. © 2013 Elsevier B.V. All rights reserved.


Xie Q.,Taiyuan University of Technology | Jing L.,Taiyuan University of Technology | Wang Z.,Taiyuan University of Technology | Wang Z.,Beijing Institute of Technology | Zhao L.,Taiyuan University of Technology
Composites Part B: Engineering | Year: 2013

The dynamic response of clamped shallow sandwich arches with core of aluminum foam has been experimentally studied by impacting the arches at mid-span with metal foam projectiles. The resistance to shock loading is measured by the permanent transverse deflection at mid-span of the arches. The deformation mechanisms of shallow sandwich arches were investigated. In addition, the deformation/failure modes of the shallow sandwich arch were classified and analyzed systematically. The effects of initial projectile momentum, face sheet thickness, core thickness and radius of curvature on the structural response were obtained. The results indicated that permanent deflection at mid-span can be efficiently controlled by increasing face sheet thickness, core thickness or appropriately increasing curvature. Meanwhile, shock resistance of the shallow sandwich arch can also be improved. The experimental results are useful in the optimum design of cellular metallic sandwich structures. © 2012 Published by Elsevier Ltd.


Sutrisno A.,University of Western Ontario | Liu L.,Taiyuan University of Technology | Dong J.,Taiyuan University of Technology | Huang Y.,University of Western Ontario
Journal of Physical Chemistry C | Year: 2012

Layered and open framework zirconium phosphates (ZrPs) have many current and potential applications in the areas of catalysis, sorption, protonic conductors, solar energy storage, crystal engineering, and ion exchange. Characterization of ZrP-based materials is important because understanding the relationship between the properties of these materials and their structures is crucial for developing new uses and for improving their performances in current applications. However, local Zr environments in many ZrPs have not been characterized directly by 91Zr solid-state NMR (SSNMR). This is because 91Zn (I = 5/2) is an unreceptive nucleus with many NMR unfavorable characteristics, leading to low sensitivity. In this work, the local environments of the zirconium centers in several ion-exchanged derivatives of layered α-ZrP (K +-, Li +-, Co(NH 3) 6 3+-ZrP) have been probed directly using 91Zr MAS, static quadrupolar echo, and/or quadrupolar Carr-Purcell-Meiboom-Gill NMR. Several layered and three-dimensional framework zirconium phosphates (ZrPO 4-DES8, ZrPO 4-DES1, ZrPO 4-DES2, ZrPOF-pyr, ZrPOF-Q1, ZrPOF-EA, and ZrPOF-DEA) with novel structures were also examined. Theoretical calculations using the CASTEP and Gaussian model cluster approaches were also performed in order to provide insights into the observed spectra. In addition to 91Zr SSNMR, 31P, 13C, and 19F SSNMR spectroscopy was also utilized to characterize the above-mentioned materials. © 2012 American Chemical Society.


Zhang X.,Taiyuan University of Technology | Liu X.,Taiyuan University of Technology | Fan C.,Taiyuan University of Technology | Wang Y.,Taiyuan University of Technology | And 2 more authors.
Applied Catalysis B: Environmental | Year: 2013

In this study, a novel BiOCl thin film with flakelike structures has been successfully prepared through electrochemical method composed of a cathodic electrodeposition and an anodic oxidation at room temperature. The samples obtained at the different oxidation voltages were analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), electronic energy spectrum (EDS), and UV-vis diffuse reflectance spectra (UV-vis DRS). The analysis results show that the morphological, structural, and optical characteristics of BiOCl thin films depend markedly on the anode oxidation voltage and the lattice orientation of BiOCl thin film is transformed mainly into (110) surface with the increasing oxidation voltages. The observed results of high-resolution transmission electron microscopy (HRTEM) confirm that pure tetragonal BiOCl thin film with the highly exposed (110) surface is obtained at 2.0V and consists of interlaced nanosheets. First-principles calculations reveal that the existence of BiOCl (110) surface states enhances the electron transition and efficient separation of photo-induced electron-hole pairs. The optimized BiOCl thin film can not only guarantee the intrinsic photochemical properties of BiOCl bulk but also exhibit additional electronic characteristics of BiOCl (110) surface, and consequently the wonderful synergistic effect between BiOCl bulk and BiOCl (110) surface accelerates the efficient separation of electron-hole pairs and produces the high reducing superoxide radicals O2 - and strong oxidizing hydroxyl radicals OH required for the degradation of organic compounds. For as-prepared BiOCl thin film, the degradation ratio of methyl orange (MO) reaches 98% under 2.5h UV irradiation at the first cycle and still remains 90% at the fifth cycle, and the COD removal efficiency of 50mg/L MO solution over BiOCl thin film achieves 73.47% after 8h reaction time. The BiOCl thin film with highly exposed {110} facets exhibits the excellent photocatalytic performance and potential application in photocatalysis field. © 2012 Elsevier B.V.


Li H.-Y.,University of Shanghai for Science and Technology | Li X.,University of Shanghai for Science and Technology | Song J.-C.,Taiyuan University of Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2012

To fully access online safety condition of mining high voltage (HV) cable and ensure the safety operation of the mine, a new notion of safety early warning system for mining HV cable was developed. Based on the research about cable aging, a set of index characterizing the insulation parameters was proposed and the weight of each index was determined with analytic hierarchy process (AHP). To compare each index from persperitive of time and space, "perfection degree" was introduced to deal with the data in the same measuring scale. Then an improved radar chart method with eigenvalue calculating algorithm was applied to the safety early warning system, in the process of which the reference samples characterizing the impairment of cable and equilibrium factor reflecting the multisource information fusion are adopted, and the result is concise, clear and intuitive. Finally, the system is tested by monitoring the 10 kV mining HV cable, the state of the cable is effectively represented by multi-dimensional data and picture, and with more superiority than other method.


In this Letter, I present a versatile strategy to enhance the near-infrared to near-infrared (NIR-to-NIR) upconversion luminescence from sub-10-nm ultra-small LaF3:Yb3+/Tm3+ colloidal nanoparticles through lanthanide doping under 980 nm laser excitation. It is interesting that the NIR-to-NIR upconversion emission at 801 nm of LaF3:Yb3+/Tm3+ nanoparticles can be improved by increasing the Tm3+ doping concentration or by introducing another lanthanide activator (Er3+ or Ho3+) as a sensitizer. The luminescence enhancement effect showed a strong dependence on the doping concentrations of activator ions (Tm3+, Er3+, or Ho3+). Particularly, adding 1 mol. % Ho3+ ions into LaF3:Yb3+/Tm3+ nanoparticles induced a 2.85-fold enhancement in NIR 801 nm emission of Tm3+ ions. The related upconversion emission mechanisms were investigated and discussed. © 2015 Optical Society of America.


Xue G.,Taiyuan University of Technology | Xue G.,Shanxi University | Liu H.,Taiyuan University of Technology | Li W.,Taiyuan University of Technology
International Journal of Mining Science and Technology | Year: 2012

Based on SEM observance, the methods of low-temperature nitrogen and isothermal adsorption were used to test and analyze the coal samples of Hancheng, and pore structure characteristics of tectonic coals were discussed. The results indicate that in the same coal rank, stratification and crack are well developed in cataclastic coal, which is mostly filled by mineral substance in the geohydrologic element abundance, results in pore connectivity variation. Granulated and mylonitic coal being of these characteristics, as develop microstructures and exogenous fractures as well as large quantity of pores resulted from gas generation and strong impermeability, stimulate the recovery of seepage coal, improve coal connectivity and enhance reservoir permeability. Absorption pore (micro-pore) is dominant in coal pore for different coal body structure, the percentage of which pore aperture is from 1 to 100 nm is 71.44% to 88.15%, including large of micro-pore with the 74.56%-94.70%; with the deformation becoming more intense in the same coal rank, mesopore enlarge further, open-end pores become thin-neck-bottle-shaped pores step by step, specific surface area of micro-pore for cataclastic coal is 0.0027 m 2/g, while mylonitic coal increases to 7.479 m 2/g, micro-pore gradually play a dominant role in effecting pore structural parameters. © 2012 Published by Elsevier B.V. on behalf of China University of Mining & Technology.


Yang H.-L.,Taiyuan University of Technology | Fan M.-Q.,Taiyuan University of Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2012

In order to discharge the slime with high ash content and thus decrease the middling cycling of column flotation, a new classification device designed for flotation tailings was developed and the classification experiments on it were carried out. The results show that effective classification can be obtained for flotation tailings. About 1/2 to 2/3 of the slime with high ash can be discharged when the proportion for underflow and the feeding flow rates are 0.2~0.4 and <40 m 3/(m 2·h), respectively. A mathematical model for the classification curve based on particle size was constructed involving a classification function and an entrainment function. It can prettily fit the partition curve with fish-hooks observed in the experiments. By introducing the flow rate, feeding concentration and the underflow proportion ratio into the model, a comprehensive multi-variant model was established. It realized the quantitative description of the partition ratio in the underflow for this new classification device employing the operating conditions and the particle size. The comprehensive model indicates that the flow rate and the concentration of the feeding play a decisive role on the classification while the underflow proportion ratio mainly influences the entrainment.


Jiao H.-Z.,Taiyuan University of Technology | Yang Z.-J.,Taiyuan University of Technology | Wang S.-P.,Taiyuan University of Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2012

Based on virtual prototyping software MSC. ADAMS, the paper built the virtual prototyping model for sprocket transmission system of scraper conveyor, the dynamic characteristics of this system under various work conditions were simulated. The distributions and rules of driving torque and it's resultant moment of motor at scraper head and tail are discussed, the driving torque reaches maximal quickly at the moment of launch and presents cyclical variability in the process of smooth running, which provides reference for the allocation of the motors power. The distributions and rules of contact force between chains and sprockets, the maximal contact force and it's corresponding position are discussed, which provides reference for finite element analysis and structure optimization of sprocket. The distributions and rules of the chain tension are discussed, which provides reference for transient dynamic analysis of sprocket transmission system.


Ding H.,Taiyuan University of Technology | Yang Z.-J.,Taiyuan University of Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2012

For the realization of the shearer cutting unit intelligent design, the principles of KBE was applied to the shearer cutting unit modern design. The knowledge acquisition method of a rough set extended model based on ε coherence criterion about the overall technical parameter of the shearer was presented and laied a reasoning foundation for the design of cutting unit. The hybrid knowledge expression model was put forward, which was mainly to the knowledge representation of object-oriented, as supplement to production rules and process knowledge representation method, and realized the integration of design object and knowledge. According to the process of design of shearer cutting unit, the fusion reasoning model building was accomplished based on the integration of CBR, RBR and MBR. The modern design system of shearer cutting unit was developed based on UG platform, which proved that the method is feasible and effective.


Niu Z.,Taiyuan University of Technology | Shi S.,Taiyuan University of Technology | Sun J.,Taiyuan University of Technology | He X.,Taiyuan University of Technology
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011

Outlier detection is a data analysis method and has been used to detect and remove anomalous observations from data. In this paper, we firstly introduced some current mainstream outlier detection methodologies, i.e. statistical-based, distance-based, and density-based. Especially, we analyzed distance-based approachandreviewed several kinds of peculiarity factors in detail. Then, we introduced sampled peculiarity factor (SPF) and a SPF-based outlier detection algorithm in order to explore a lower-computational complexity approach to compute peculiarity factor for real world needs in our future work. © 2011 Springer-Verlag.


Wang R.,Taiyuan University of Technology
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011

Realizes the flotation process cleaned coal ash soft Sensor is the key of flotation process automation. First introduction to least square support vector machines algorithm, subsidiary variable choice research on flotation process cleaned coal ash soft sensor is carried out, reasonable subsidiary variable is selected by experiment, soft sensor accuracy of coal change is proposed, experiment show that model accuracy is sensitive for coal change. This soft sensor model is help to flotation process automatic control. © 2011 Springer-Verlag.


Donghua C.,Taiyuan University of Technology | Wenjie Y.,Taiyuan University of Technology
2011 International Conference on Consumer Electronics, Communications and Networks, CECNet 2011 - Proceedings | Year: 2011

Ant colony algorithm is a bionic optimization algorithm, it can solve combinatorial problems effectively. For the problem of the test suite reduction, this algorithm could find the balance point between the speed and the accuracy of solution. Unlike other existing algorithms, this algorithm used test cost criteria, as well as the test coverage criteria. Finally, the paper presented the results, the results is given by the others classical algorithms compared with this algorithms. The results show that this algorithm can significantly reduce the size and the cost of the test-suite, and achieved higher effectiveness of test-suite minimization. © 2011 IEEE.


Li H.,University of Shanghai for Science and Technology | Liu Z.,University of Shanghai for Science and Technology | Song J.,Taiyuan University of Technology
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2015

Aim to the integration of cyber physical systems (CPS), a relevance vector machine (RVM) based data-driven method was proposed for real-time static security situational awareness. RVM is a general Bayesian probabilistic framework to learn the kernel-based classification model, in which a set of hyperparameters are imposed to the hierarchical priors over model parameters for obtaining the sparse solutions, and the Bernoulli distribution is incorporated to output a consistent estimation of the posterior probability. The operation conditions were firstly generated according to the dispatches of the day-ahead markets and the pre-fault feature sets with contingency class memberships were obtained. Then a distance-based Relief algorithm was employed for feature rank and selection. Finally, RVM learning for classification was applied for security recognition. A case studied in the IEEE 30-bus system shows the proposed method can provide exceedingly sparse solutions, high accuracy and probabilistic outputs, further clarifying its superiority in security awareness. © 2015 Chin. Soc. for Elec. Eng.


Li M.,Taiyuan University of Technology | Lei M.,Taiyuan University of Technology | Munjiza A.,Queen Mary, University of London | Wen P.H.,Taiyuan University of Technology | Wen P.H.,Queen Mary, University of London
International Journal for Numerical Methods in Engineering | Year: 2015

Based on the one-dimensional differential matrix derived from the Lagrange series expansion, the finite block method was recently developed to solve both the elasticity and transient heat conduction problems of anisotropic and functionally graded materials. In this paper, the formulation of the Lagrange finite block method with boundary type in the strong form is presented and applied to non-conforming contact problems for the functionally graded materials subjected to either static or dynamic loads. The first order partial differential matrices are only needed both in the governing equations and in the Neumann boundary condition. By introducing the mapping technique, a block of quadratic type is transformed from the Cartesian coordinate of global system to the normalized coordinate with eight seeds. Time dependent partial differential equations are analyzed in the Laplace transformed domain and the Durbin's inversion method is applied to determine all the physical values in the time domain. Conforming and non-conforming contacts are investigated by using the iterative algorithm with full load technique. Illustrative numerical examples are given and comparisons have been made with analytical solutions. © 2015 John Wiley & Sons, Ltd.


Qi X.,Shanxi University | Hou J.,Taiyuan University of Technology
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012

In this paper, we present a characterization of optimal entanglement witnesses in terms of positive maps and then provide a general method of checking optimality of entanglement witnesses. Applying it, we obtain indecomposable optimal witnesses that have no spanning property. These also provide examples that support a recent conjecture saying that the so-called structural physical approximations to optimal positive maps (optimal entanglement witnesses) give entanglement breaking maps (separable states). © 2012 American Physical Society.


Cheng H.-Q.,Taiyuan University of Technology | Wang H.-K.,Taiyuan University of Technology | Wang H.,Taiyuan University of Technology
Proceedings - 2011 International Conference on Network Computing and Information Security, NCIS 2011 | Year: 2011

In wireless sensor networks' (WSNs') applications, the ability of sensor node to estimate their accurate position is crucial. In this paper, we develop a modified weighted centroid location algorithm (WCA), which can degrade the effects of the density of beacon nodes and uniformity of deployment. By using weighted average of the received beacon nodes' coordinates instead of arithmetic mean as the estimation results, receivers can obtain optimum localization results. The performance analysis of both WCA and centroid algorithm (CA) are presented. Simulation results show that WCA can operate efficiently by using weighted centroid mechanisms. © 2011 IEEE.


Bai Z.,Taiyuan University of Technology | Zhang X.,Taiyuan University of Technology | Zhang Y.,Taiyuan University of Technology | Guo C.,Taiyuan University of Technology | Tang B.,Taiyuan University of Technology
Journal of Materials Chemistry A | Year: 2014

In this work, porous Mn3O4 nanorods have been fabricated through the decomposition of MnOOH nanorods under an inert gas. The sample shows a high BET surface area of 27.6 m2 g-1 and a narrow pore size distribution of 3.9 nm. Because of the excellent porous geometry and one-dimensional structure, the porous Mn3O4 nanorods display outstanding electrochemical performance, such as high specific capacity (901.5 mA h g-1 at a current density of 500 mA g-1), long cycling stability (coulombic efficiency of 99.3% after 150 cycles) and high rate capability (387.5 mA h g-1 at 2000 mA g-1). Very interestingly, the porous Mn3O4 nanorods are converted to Mn3O4 following electrochemical reaction, which does not occur with nonporous Mn3O4 nanorods. The possible reason may be ascribed to the improved kinetics of the porous structure. This journal is © the Partner Organisations 2014.


Wang W.,Taiyuan University of Technology | Zhao Q.,Taiyuan University of Technology | Dong J.,Taiyuan University of Technology | Li J.,Taiyuan University of Technology
International Journal of Hydrogen Energy | Year: 2011

A novel silver oxides oxygen evolving catalyst (Ag-OEC) for hydrogen production by water splitting was formed in situ on an indium tin oxide anode, in a near-neutral potassium tetraborate (K2B4O 7) electrolyte. The catalyst exhibited high activity and low overpotential for O2 evolution under mild conditions. The main functional composition of the catalyst was a redox couple of Ag 2O/AgO. Catalytic activity during oxygen evolution was evaluated by cyclic voltammetry and Tafel plot. The effects of the concentration, temperature, and pH of K2B4O7 solution on the catalyst, and the Faradaic efficiency of the oxygen evolving reaction were examined. The results show that the Ag-OEC exhibits excellent oxygen evolution properties, with an oxygen evolving overpotential of 318 mV at a current density of 1 mA/cm2. © 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights.


Jun Y.,Taiyuan University of Technology | Xueying Z.,Taiyuan University of Technology
Communications in Computer and Information Science | Year: 2011

It is the key for improving the control and management of smart grid to know how to make multiple utilization of internet of things technologies better. In this paper, the relationship between internet of things and smart grid is analyzed. This paper shows that smart grid is based on internet of things. The internet of things technologies needs of smart grid are put forward. Finally, detailed application process and the corresponding technologies are proposed aiming at the transmission link of smart grid. © 2011 Springer-Verlag.


Wang Y.,Taiyuan University of Technology | Li Y.,Taiyuan University of Technology
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011

Because of light scattering and absorbing in dust environment, it is difficult to detect obstacles with camera. In order to solve this problem, a method of obstacles detection in dust environment from a single image was presented. The method realized distance detection and contour detection for obstacle in dust environment. First, depth map of dust image and geometric reasoning approach based on imaging model of a camera were combined to detect the distance between camera and obstacle of any shape. Then, depth map was applied to detect the contour of the obstacle in dust environment. Namely, edges belonging to contours were selected by using depth map. The validity and feasibility of the method was fully demonstrated by the experiments. The method provides a simple and economical way to detect obstacles in dust environment. © 2011 Springer-Verlag.


Rui W.,Taiyuan University of Technology | Gang L.,Taiyuan University of Technology
Communications in Computer and Information Science | Year: 2011

Considering the stochastic volatility of the wind turbine gearbox oil temperature, the wavelet packet is used to eliminate its noise. On this basis, the grey model is applied to forecast the wind turbine gearbox oil temperature. The predicted results show that the wavelet packet and the grey prediction method have better forecast accuracy. The wind turbine gearbox oil temperature trends can be predicted timely and accurately. © 2011 Springer-Verlag.


Zhang R.,Taiyuan University of Technology | Wang B.,Taiyuan University of Technology | Liu H.,Taiyuan University of Technology | Ling L.,Taiyuan University of Technology
Journal of Physical Chemistry C | Year: 2011

Catalytic hydrogenation of CO2 to methanol is a promising way to recycle and utilize CO2. In this study, the elementary steps leading to HCOO and CO formation have been explored to identify hydroxylation effect of the oxide support on the selectivity in CO2 hydrogenation on Cu/γ-Al2O3 catalyst by the density functional theory (DFT) slab calculations. Two models: Cu4 cluster supported on the dry γ-Al2O3(110) surface, D(Cu4), and on the hydroxylated γ-Al2O3(110) surface, H(Cu4), have been used to model Cu/γ-Al2O3. On D(Cu4), the formation of HCOO is preferred kinetically. On H(Cu4), HCOO formation is still kinetically favorable. These results indicate that the hydroxylation of γ-Al 2O3 support cannot alter the pathway of CO2 hydrogenation forming the dominate product HCOO, and ultimately, the selectivity of CO2 hydrogenation for HCOO formation on Cu/γ-Al 2O3 is higher, which supports the experimental fact that Al2O3-supported Cu catalyst is widely used to synthesize methanol by CO2 hydrogenation. © 2011 American Chemical Society.


Wei G.,Taiyuan University of Technology | Wei G.,Ningbo University of Technology | Liu H.,Taiyuan University of Technology | Shi C.,Ningbo University of Technology | And 3 more authors.
Journal of Physical Chemistry C | Year: 2011

In this work, we report the temperature-dependent field emission properties of 3C-SiC nanoneedles (SiCNNs) in the range of room temperature (RT) to 500 °C. SiCNNs are synthesized via catalyst-assisted pyrolysis of a polyaluminasilazane precursor. The obtained SiC nanostructures are needlelike shaped with numerous sharp corners around the tiny tips. Field emission characteristics show that turn-on field (Eto) of as-synthesized SiCNNs are ranged in 1.30 to 0.66 V/μm with the temperature raised from RT to 500 °C. At a fixed electric field of 1.37 V/μm, about a three-order-of-magnitude increase of the emission current level has been observed. We attribute the significant reduction of Eto and the remarkable increase of emission current to the decrease of work function induced by the raise of temperatures. © 2011 American Chemical Society.


In this work, colloidal hexagonal-phase -NaYF4:Nd3+/ Yb3+/Ho3+/NaYF4:Nd3+/Yb3+ core/shell nanoparticles with intense visible upconversion emissions under 808-nm laser excitation were prepared. Compared with the core-only nanoparticles, a maximum 990-fold overall enhancement in the emission intensity of Ho3+ ions was achieved with the help of active-shell coating design, due to the significant increase in the near-infrared absorption and efficient energy transfer from Nd3+ primary-sensitizers to Ho3- activators via Yb3+ bridging sensitizers. The luminescence-enhancement effect exhibited a strong dependence on the doping concentrations of NaYF4:Nd3+/Yb3+ active-shell. The optimal concentrations of Nd3+ and Yb3+ ions in the active-shell layer were found to be 30 and 5 mol. %, respectively.Moreover, the upconversion emission intensity of NaYF4:Nd3+/Yb3+- coated nanoparticles was about 2.5 times higher than the one coated with a NaYF4:Nd3+ active-shell. © 2015 Optical Society of America.


cui H.,Taiyuan University of Technology | Yao R.,China Institute for Radiation Protection | Xu X.,China Institute for Radiation Protection | Xin C.,China Institute for Radiation Protection | Yang J.,Taiyuan University of Technology
Atmospheric Environment | Year: 2011

CALPUFF is an atmospheric source-receptor model recommended by the US Environmental Protection Agency (EPA) for use on a case-by-case basis in complex terrain and wind condition. As the bulk of validation of CALPUFF has focused on long-range or short-range but long-term dispersion, we can not gauge the reliability of the model for predicting the short-term emission in near-field especially complex terrain, and sometimes this situation is important for emergency emission. To validate the CALPUFF's application in such condition, we carried out a tracer experiment in a near-field complex terrain setting and used CALPUFF atmospheric dispersion model to simulate the tracer experiment in real condition. From the centroid trajectory comparison of predictions and measures, we can see that the model can correctly predict the centroid trajectory and shape of tracer cloud, and the results also indicate that sufficient observed weather data only can develop a good wind field for near-field. From the concentration comparison in each arc, we can see the model underestimate horizontal extent of tracer puff and can not reflect the irregular characters showed in measurements. The result of global analysis is FOEX of -25.91%, FA2 of 27.06%, FA5 of 61.41%. The simulations shows that the CALPUFF can simulate the position and direction of tracer cloud in near-field complex terrain but underestimate over measurements especially in peak concentrations. © 2011 Elsevier Ltd.


Liu Z.-X.,Taiyuan University of Technology | Feng Z.-C.,Taiyuan University of Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2012

Microscopic mechanism of adsorption heat's generation was expounded systematically. On the basis of the potential energy model, two-energy-state model was got and the computational formula of the corresponding adsorption heat was deduced. On the basis of the grand canonical ensemble theory, the Langmuir monolayer model of statistical mechanics was got, and the computational formula of the corresponding adsorption heat was deduced. This paper cited De Broglie thermal average wavelength, and got the approximate computational formula of adsorption heat based on the Langmuir monolayer model. To compare the two models, it shows that adsorption heat is much affected by the adsorption capacity, adsorption centers and the average distance between molecules, and that we should use different physical models for analysis towards the outer layer of methane (relative to the coal surface) and the inner methane. On the basis of the Langmuir monolayer model, from perspective of adsorption, the fractal features of pore structure and fracture structure was studied, the two-dimensional flat surface adsorption to the fractal surface adsorption was extended, and a fractal dimension based on De Broglie thermal average wavelength was got.


Yan K.,Taiyuan University of Technology | Wu X.,Taiyuan University of Technology | An X.,Taiyuan University of Technology | Xie X.,Taiyuan University of Technology
Journal of Alloys and Compounds | Year: 2013

Four spinel ferrites (CuFe2O4, NiFe2O 4, CoFe2O4 and ZnFe2O4) were successfully synthesized by a citrate assisted sol-gel method using ethylenediaminetetraacetic acid (EDTA) as a templating agent. The four resultant spinel ferrites were systematically characterized by different techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM). It was indicated that all the resultant spinel ferrites obtained by this novel method had the single-phase with high crystallinity. Meantime, highly homogeneous cubic structure with nice morphology was successfully fabricated. The resultant spinel ferrites were highly selective for the oxidation of benzyl alcohol and display significant difference among their activities. It was found that the spinel CoFe2O4 catalyst display the best performance, whereby 93% selectivity of benzaldehyde was achieved at close to 63% conversion. © 2012 Elsevier B.V. All rights reserved.


Guo M.L.,Taiyuan University of Technology
Advanced Materials Research | Year: 2014

Expansive soil mixed with a certain amount of lime in the post-isostatic pressing, as measured through the oedometer specimen expansion and contraction coefficient changes. Test divided load and no-load charge plus two groups, drawn economically reasonable dosage of lime for building design and construction to provide evidence. © (2014) Trans Tech Publications, Switzerland.


Jianfang C.,Xinzhou Teachers University | Junjie C.,Taiyuan University of Technology | Qingshan Z.,Xinzhou Teachers University
Cybernetics and Information Technologies | Year: 2014

In order to solve the problems of security threats on workflow scheduling in cloud computing environments, the security of tasks and virtual machine resources are quantified using a cloud model, and the users' satisfaction degree with the security of tasks assigned to the virtual resources is measured through the similarity of the security cloud. On this basis, combined with security, completion time and cost constraints, an optimized cloud workflow scheduling algorithm is proposed using a discrete particle swarm. The particle in the particle swarm indicates a different cloud workflow scheduling scheme. The particle changes its velocity and position using the evolution equation of the standard particle swarm algorithm, which ensures that it is a feasible solution through the feasible solution adjustment strategies. The simulation experiment results show that the algorithm has better comprehensive performance with respect to the security utility, completion time, cost and load balance compared to other similar algorithms.


Pan P.J.,Taiyuan University of Technology
Advanced Materials Research | Year: 2014

The energy dissipation design method has received more attention by engineering circle. Nowadays, the buckling restrained braces (BRBs) are used in higher structures being dissipation energy components. So, it is very necessary to determine the damage quantity of BRBs under earthquake. Firstly, the meaning of the damage quantity of BRBs is clarified based on the energy theory. Secondly, a single degree of freedom analyses model which is suitable to the frame structure is proposed. The nonlinear dynamic time-history analysis of BRBs system is carried out by using FEMS software of ANSYS 11.0 and seismic response of BRBs is obtained. Finally, a practical calculation model of the Damage quantity of BRBs is established. Using MATLAB software, the Damage quantity of BRBs is obtained. © (2014) Trans Tech Publications, Switzerland.


Li T.T.,Taiyuan University of Technology
Advanced Materials Research | Year: 2014

Abundant historic buildings still exist in Shanxi, of which architectures built in Song, Liao and Jin Dynasty are in the majority, especially the number and area of murals in this period ranking first in the nationwide, which embody the essence of Chinese traditional culture with great artistic value. The constant abundance and development of culture and art in ancient China are represented on murals of this period, and valuable materials have been provided for our understanding towards the painting technique of ancient murals in Shanxi, which is beneficial for our study on the historical origin of traditional architecture and mural art meanwhile. This paper focuses on the discussion and analysis comprehensively of 6 existing murals including murals of Shousheng Temple of Ruicehng, Shanxi, murals of the Great Hall of Mahavira in Kaihua Temple, Gaoping, murals of Sheli Tower in Jueshan Temple of Lingqiu, murals of Sakyamuni Pagoda in Fogong Temple of Ying County, murals of Amitabha Hall in Chongfu Temple of ShuoZhou and murals of Wenshu Hall in Yanshan Temple of Fanshi. The emergence of mural art dates back to the primitive society, patterns of design relating to daily life have been painted on the rock or on the wall of the cavern where human beings live, which are the embryonic form of murals. Ultimately, the emergence and development of murals depend on the architectural development. With the introduction of Buddhism into China after Tang Dynasty, the transmission of Buddhist culture and the development of Buddhist temple art are promoted, while the mural has been developed into a mature stage in Song, Liao and Jin Dynasty. Abundant resources in architecture and valuable relics of murals in Taoist temples exist in Shanxi Region. Existing murals of Song, Liao and Jin Dynasty in Shanxi have reached to a thousand square meter ranking first in the nationwide. This paper discusses the interdependent origin of architectures and murals through investigation, classification and analysis on Song, Liao and Jin Dynasty in Shanxi Region. © (2014) Trans Tech Publications, Switzerland.


With the environment increasingly worsening, global warming has become an environmental problem challenged around the world. The cognition of low carbon and environmental protection has been widely spread and applied in urban planning construction. Universities are the frontiers of scientific research. At university such aspects like construction energy conservation and the use of new material have been put into practice, and under the guidance of planning, construction, management departments and others, the ideas of low carbon and ecology is promoted to build the campus with sustainable development. Universities play a leading role for all walks of life in society. © (2014) Trans Tech Publications, Switzerland.


Xi S.,Taiyuan University of Technology
Applied Mechanics and Materials | Year: 2010

Although Chinese industrial design has developed for over 30 years, the combination of design principles and practice could not meet the challenges of the new era. Design management could be used in reconstructing the core competence of Chinese enterprises. An atmosphere of effective communication and respect for each other is useful in achieving design objective. Design-appraising system will be eventually established by integrating design theory with practice. © (2010) Trans Tech Publications.


Wang L.,Taiyuan University of Technology
Aggression and Violent Behavior | Year: 2016

Attitude toward intimate partner violence has been consistently demonstrated as one of the prominent predictors of IPV. Studies have frequently indicated several factors influencing attitude concerning IPV including age, gender, education, residency, economic status, patriarchal gender role and so on. Yet there is surprisingly little research focusing on the relationship of those factors. To promote the understanding of attitude toward IPV, and to contribute to the campaign of IPV-prevention, this study reviewed the factors associated with attitude concerning IPV and concluded that education might be the most crucial one among all the factors, as factors such as age, gender and residency were substantively reflected different education level, and factors as economic status, participating in household decision, ability to access media, and patriarchal gender role were deeply rooted in education. As a result, further research of specific population-based which might offer clearer insight into factors influencing attitude concerning IPV is required, and more effort of government in promoting individual's education level is demanded. © 2016 Elsevier Ltd


Duan F.,Taiyuan University of Technology | Chen C.,Shanxi Institute of Coal CAS Chemistry | Wang G.,Shanxi Institute of Coal CAS Chemistry | Yang Y.,Taiyuan University of Technology | And 2 more authors.
RSC Advances | Year: 2014

Molecularly imprinted polymers on GO nanosheets (MIPs/GO) for desulfurization are synthesized using dibenzothiophene (DBT) as template, methacrylic acid (MAA) as monomer and ethylene glycol dimethacrylate (EGDMA) as cross-linker. The formation of this hybrid material is verified by Fourier transform infrared spectroscopy, thermal gravimetric and atomic force microscopy analysis. The adsorption results show that the prepared MIPs/GO exhibit excellent adsorption capacity (up to 181.9 mg g-1 at 298 K) and fast mass transfer and binding kinetics for DBT. The kinetics and isotherm data can be well described by the pseudo-first-order kinetic model and the Freundlich isotherm, respectively. Competitive adsorption experiments demonstrate that MIPs/GO show higher affinity toward target molecule DBT than toward structural analogue benzothiophene. © 2014 The Royal Society of Chemistry.


Li C.,Yangtze Normal University | Dang S.,Yangtze Normal University | Han P.,Taiyuan University of Technology
Guangxue Xuebao/Acta Optica Sinica | Year: 2010

Geometrical structure of CdS with vacancy was optimized by using density functional theory (DFT) based on first-principle ultrasoft pseudopotential method. Optimized results showed that the vacancy resulted in local lattice distortion and the relaxation of neighboring atoms. Then vacancy effects on electronic structure (energy-band structure and electron-state density) of CdS were analyzed. The results revealed that S vacancy made the band gap narrower and Cd vacancy made it wider, but CdS with S and Cd vacancy were direct band gap semiconductor. The optical properties of CdS with vacancies were investigated. The results indicated that changes on optical properties mainly focused on low-energy region because of the change of electronic structure of atom neighbor vacancy.


Zhang X.,Taiyuan University of Technology | Huang X.,Taiyuan University of Technology | Ma Y.,Taiyuan University of Technology | Lin N.,Taiyuan University of Technology | And 2 more authors.
Applied Surface Science | Year: 2012

Stainless steels are one of the most common materials used in health care environments. However, the lack of antibacterial advantage has limited their use in practical application. In this paper, antibacterial stainless steel surfaces with different Cu contents have been prepared by plasma surface alloying technology (PSAT). The steel surface with Cu content 90 wt.% (Cu-SS) exhibits strong bactericidal activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) within 3 h. Although the Cu-containing surface with Cu content 2.5 wt.% (CuNi-SS) can also kill all tested bacteria, this process needs 12 h. SEM observation of the bacterial morphology and an agarose gel electrophoresis were performed to study the antibacterial mechanism of Cu-containing stainless steel surfaces against E. coli. The results indicated that Cu ions are released when the Cu-containing surfaces are in contact with bacterial and disrupt the cell membranes, killing the bacteria. The toxicity of Cu-alloyed surfaces does not cause damage to the bacterial DNA. These results provide a scientific explanation for the antimicrobial applications of Cu-containing stainless steel. The surfaces with different antibacterial abilities could be used as hygienic surfaces in healthcare-associated settings according to the diverse requirement of bactericidal activities. © 2012 Elsevier B.V.


Yang Y.,Taiyuan University of Technology | Zhang Y.,Taiyuan University of Technology | Li S.,Taiyuan University of Technology | Liu X.,Taiyuan University of Technology | Xu B.,Taiyuan University of Technology
Applied Surface Science | Year: 2012

Poly(2-acrylamido-2-methylpropanesulfonic acid) (PAMPS) was grafted on the surface of carbon microspheres (CMSs), which were modified in prior by a mixed acid (HNO 3 and H 2SO 4) oxidation and 3-methacryloxypropyl trimethoxysilane silanization. Then, the molecularly imprinting polymerization was carried out towards the macromolecule PAMPS grafted on the surface of CMSs using dibenzothiophene (DBT) as template, ethylene dimethacrylate as cross-linking agent and (NH 4) 2S 2O 8 (APS) as initiator to prepare surface molecularly imprinted polymer (MIP-PAMPS/CMSs) for adsorbing DBT. The optimized conditions of grafting PAMPS, including AMPS dosage, APS content, reaction temperature and reaction time, were emphasized in this paper. The morphology of the samples was characterized by field emission scanning electron microscopy. The functional groups were analyzed qualitatively by Fourier transform infrared spectrometry. The grafting degree of PAMPS was investigated by thermogravimetry. The results show that the preferable AMPS dosage, APS content, reaction temperature and time were 5 g, 0.15 g, 70°C and 12 h, respectively, for preparing PAMPS/CMSs composite on the basis of 1.0 g of silanized-CMSs. The absorbing characteristic of MIP-PAMPS/CMSs toward DBT was studied preliminarily with dynamic adsorption. In the experiment of dynamic adsorption, MIP-PAMPS/CMSs and non-imprinted polymer (NIP-PAMPS/CMSs) were compared with respect to their rapid adsorption in 1 mmol/L of DBT solution in n-hexane. When the first 1 mL of 1 mmol/L DBT solution was injected and flowed through a column packed with 0.1 g of MIP-PAMPS/CMSs, the content of DBT reduced to 0.265 mmol/L, that is, decreased significantly from 279 to 74 ppm. When 3 mL of DBT solution was flowed through the packed column, the adsorption of MIP-PAMPS/CMSs toward DBT reached saturation with the maximum adsorption amount of 1.38 × 10 -2 mmol/g and the overall adsorption efficiency of 46%, while NIP-PAMPS/CMSs adsorbed only 1.66 × 10 -3 mmol/g of DBT. It is suggested that the MIP-PAMPS/CMSs had much better adsorption property towards DBT than NIP-PAMPS/CMSs. © 2012 Elsevier B.V.


Han G.,Taiyuan University of Technology | Wang Y.,Taiyuan University of Technology
Zhongguo Jiguang/Chinese Journal of Lasers | Year: 2010

This paper proposes a method of faults location for transmission lines by using broadband chaotic signals, which is experimentally demonstrated with a chaotic semiconductor laser. Chaotic signal is obtained by converting the chaotic light from the chaotic laser diode, and divided into two signals, one serving as probe signal and the other serving as reference signal. Faults are located by correlating the echo of probe signal with the reference one. The spatial resolution is determined by the time resolution of correlation curve. Experimental results show that 7.5 cm resolution can be readily achieved by common laser diode.


Wang B.,Taiyuan University of Technology | Zhao T.,Taiyuan University of Technology | Wang H.,Taiyuan University of Technology
Chinese Optics Letters | Year: 2012

Chaotic laser radar based on correlation detection is a high-resolution measurement tool for remotely monitoring targets or objects. However, its effective range is often limited by the side-lobe noise of correlation trace, which is always increased by the randomness of the chaotic signal itself and other transmission channel noises or interferences. The experimental result indicates that the wavelet denoising method can recover the real chaotic lidar signal in strong period noise disturbance, and a signal-to-noise ratio of about 8 dB is increased. Moreover, the correlation average discrete-component elimination algorithm significantly suppresses the side-lobe noise of the correlation trace when 20 dB of chaotic noise is embedded into the chaotic probe signal. Both methods have advantages and disadvantages. © 2012 Chinese Optics Letters.


Zuo Z.,Taiyuan University of Technology | Huang W.,Taiyuan University of Technology | Han P.,Taiyuan University of Technology
Applied Surface Science | Year: 2012

Density functional theory (DFT) combined with conductor-like solvent model (COSMO) have been performed to study the solvent effects of H 2 adsorption on Cu(h k l) surface. The result shows H 2 can not be parallel adsorbed on Cu(h k l) surface in gas phase and only vertical adsorbed. At this moment, the binding energies are small and H 2 orientation with respect to Cu(h k l) surfaces is not a determining parameter. In liquid paraffin, when H 2 adsorbs vertically on Cu(h k l) surface, solvent effects not only influences the adsorptive stability, but also improves the ability of H 2 activation; When H 2 vertical adsorption on Cu(h k l) surface at 1/4 and 1/2 coverage, H-H bond is broken by solvent effects. However, no stable structures at 3/4 and 1 ML coverage are found, indicating that it is impossible to get H 2 parallel adsorption on Cu(h k l) surfaces at 3/4 and 1 ML coverages due to the repulsion between adsorbed H 2 molecules. © 2011 Elsevier B.V. All rights reserved.


Wang B.,Taiyuan University of Technology | Song L.,Taiyuan University of Technology | Zhang R.,Taiyuan University of Technology
Applied Surface Science | Year: 2012

CH 4 dehydrogenation on Rh(1 1 1), Rh(1 1 0) and Rh(1 0 0) surfaces has been investigated by using density functional theory (DFT) slab calculations. On the basis of energy analysis, the preferred adsorption sites of CH x (x = 0-4) and H species on Rh(1 1 1), Rh(1 1 0) and Rh(1 0 0) surfaces are located, respectively. Then, the stable co-adsorption configurations of CH x (x = 0-3) and H are obtained. Further, the kinetic results of CH 4 dehydrogenation show that on Rh(1 1 1) and Rh(1 0 0) surfaces, CH is the most abundant species for CH 4 dissociation; on Rh(1 1 0) surface, CH 2 is the most abundant species, our results suggest that Rh catalyst can resist the carbon deposition in the CH 4 dehydrogenation. Finally, results of thermodynamic and kinetic show that CH 4 dehydrogenation on Rh(1 0 0) surface is the most preferable reaction pathway in comparison with that on Rh(1 1 1) and Rh(1 1 0) surfaces. © 2011 Elsevier B.V. All rights reserved.


Xu Y.,Taiyuan University of Technology | Zhang Y.,Taiyuan University of Technology | Wang Y.,Taiyuan University of Technology | Zhang G.,Taiyuan University of Technology | Chen L.,Taiyuan University of Technology
Journal of Analytical and Applied Pyrolysis | Year: 2013

The results of low-temperature pyrolysis of lignite are presented in this paper. The investigation focused on the effect of pyrolysis temperature on the gaseous product distribution, as well as morphological and structural variation. The gases evolved were analyzed by gas chromatography. Graphs of evolved gaseous components versus temperature were constructed to study their evolution characteristics. Morphological characteristics were observed at different pyrolysis temperatures. The semi-char surface had numerous bumps and hollows with deep cracks after low-temperature pyrolysis. The structural variation between the raw lignite and semi-char product was determined by Brunauer-Emmett-Teller techniques. The semi-char had well-developed flow structures with irregular shapes and appeared fairly molten, which indicated structural change during the evolution of the gaseous products. © 2013 Elsevier B.V. All rights reserved.


Dong J.,Taiyuan University of Technology | Cheng Z.,Taiyuan University of Technology | Li F.,Taiyuan University of Technology
Journal of Analytical and Applied Pyrolysis | Year: 2013

Several organic and inorganic pollutants are released during coal utilization such as polycyclic aromatic hydrocarbons (PAHs). PAHs, due to their carcinogenic properties pose potential health hazards. The current work focused on the behavior of the 16 PAHs during pyrolysis process, an important step of all coal thermal conversion including combustion, gasification, and carbonization. The experiments were performed using a CDS-5250 pyroprobe which could be heated fast. The pyroprobe was coupled with GC-MS (Thermo DSQII/FOCUS GC) and the pyrolysis products were analyzed in situ. The emissions of the 16 USEPA priority-controlled polycyclic aromatic hydrocarbons from Western Chinese coal were measured under different pyrolysis conditions. The results showed that the emission concentrations of PAHs reach a maximum at a pyrolysis temperature of 800 C. Emission concentrations of PAHs decreased with increasing rates of pyrolysis heating. PAHs emissions increased gradually with coal rank under the same pyrolysis conditions. A correlation between the yield of PAHs, coal rank and maceral was also demonstrated. Also in this study, the variety trend of the each species of 16 PAHs with pyrolysis temperature was observed and the reasons were discussed. © 2013 Elsevier B.V. All rights reserved.


Wang M.,Taiyuan University of Technology | Hu Y.,Canadian Light Source Inc. | Wang J.,Taiyuan University of Technology | Chang L.,Taiyuan University of Technology | Wang H.,University of Saskatchewan
Journal of Analytical and Applied Pyrolysis | Year: 2013

Sulfur transformation of inertinite-rich coals, which were sampled from three Western China coal mines, Xinjiang Hami (HM), Ningxia Lingwu (LW) and Shendong (SD), during pyrolysis is studied through measuring the release of H2S and COS gases by gas chromatography with flame photometric detector and through analyzing the sulfur forms in raw coals and chars from pyrolysis by X-ray absorption spectroscopy (XAS). It is revealed that the transformation of sulfur during coal pyrolysis is closely linked with coal properties, such as the vitrinite/inertinite ratio, alkaline mineral contents (especially calcium compounds) and H/C atomic ratio for three inertinite-rich coals. Comparisons are performed with a coal sample taken from Pingsuo (PS) coal mine located in North China, of which the properties are significantly different. The maximal release temperature of sulfur-containing gases for the pyrolysis of inertinite-rich coal is higher than that of the PS coal. The release of the S-containing gases in inertinite-rich coals has a maximal temperature interval around 600 C and this is associated with the conversions of inorganic sulfur species, such as pyrite transforming to FeS observed by the XAS in chars of these coals. During the process of pyrolysis, the organic sulfur compounds in inertinite-rich coal can be oxidized to form sulfoxide-like species due to the decomposition of oxygen-containing function groups in the coal matrix, but the active sulfur in PS coal can react with fresh char to form relatively stable thiophene structures. The formation of COS during the pyrolysis of inertinite-rich coals is mainly due to secondary reactions between H2S with CO and/or CO2. © 2013 Elsevier B.V. All rights reserved.


Wang X.,Taiyuan University of Technology | Xue Y.,Taiyuan University of Technology
Fuzzy Sets and Systems | Year: 2014

In this paper, we focus on the characterizations of various property indicators of fuzzy relations by means of left and right traces. The characterized indicators include those of reflexivity, T-asymmetry, S-completeness, T-transitivity, negative S-transitivity, T-S-semitransitivity and T-S-Ferrers property. The investigation can be regarded as an extension of and complement to the work done by Fodor on characterizing these properties in terms of traces. © 2014 Elsevier B.V.


Jiao Y.,Taiyuan University of Technology | Shi J.,Taiyuan University of Technology
Proceedings - 2012 International Conference on Computing, Measurement, Control and Sensor Network, CMCSN 2012 | Year: 2012