bluuebunny/crossref_metadata_2025 huggingface dataset:
Rotor Position Phase Correction for Sensorless Brushless DC Motor Based on Line Back EMF
Authors: Li Zi Cheng , Ou Zi Yu , Cheng Shan Mei
Published: October 2011

This paper proposes a novel rotor position estimation method based on line back EMF for brushless DC motor (BLDCM). The relationship between position phase error and the symmetric line back EMF is analyzed. It is noted that line back EMF error can exactly reflect rotor position phase error. If the amplitude of line back EMF at the beginning of commutation is equal to the amplitude of line back EMF at the end of commutation, the waveform of line back EMF should be symmetric. Based on the above analysis, a closed loop control method to correct rotor position phase is presented. Line back EMF error is employed to keep the waveform of line back EMF symmetrical by PI controller. This paper also develops a sensorless BLDCM driver to implement the proposed method based on DSP and the experimental results prove the validity of the proposed method.
Study of Hydrothermal Synthesis of Ce0.67Zr0.33O2 Nanorods and Catalytic Property to CO
Authors: Jia Ying , Liu Tian Tian , Luo Cheng
Published: October 2011

Ce0.67Zr0.33O2 (CZ) nanorods are successfully synthesized by glycol-assisted hydrothermal method using zirconium oxychloride, cerium nitrate and urea, with the presence of sodium hypochlorite. The products are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectra. The catalytic oxidation characters about Pd/CZ three-way catalyst (TWC) prepared with different loads of Pd are also investigated. The results show that the as-prepared Pd/CZ has excellent catalytic oxidation character to CO.
Studies on the Grid-Connected Characteristics about Large-Scale Photovoltaic Power Station in Weak Grid Systems
Authors: Jiang Hui , Li Zhi Wei , Zheng Xin
Published: October 2011

This paper made some researches of modeling on the systems of the large-scale photovoltaic（PV） power station, and established the PV model, the rectifier and inverter circuits and so on. Using MATLAB and PSASP, simulation and analysis of grid-connected characteristics about the large-scale PV power station in weak grid systems were carried out, focusing on the transient stability in the fault condition of the line-side and the power quality. These two simulation results had good consistency, which demonstrated the accuracy of the large-scale PV power station model in this paper and the analysis of its grid-connected characteristics. The conclusion of this paper will provide some theoretical basis of improving the stability of grid-connected and reducing the harmonic current in weak grid systems, and will also provide some theoretical basis and the guide of grid-connected for the new energy strategy of our country in the future.
Selection of Pantograph Strip/Contact Wire Couples in Catenary/Pantograph System
Authors: Ding Tao , Chen Guang Xiong , Xiao Shu Fen , Xie Li
Published: October 2011

A serials of experiments were carried on the pin-on-disc friction and wear tester. The friction and wear behaviors of on four materials couple with electric current were studied on in different conditions. The result indicates that properties of materials couple have a significant influence on the test results. The friction coefficient is the highest in process of the copper-impregnated metallized carbon rubbing against pure copper couple, and its wear volume of carbon strip material is also the largest. However, the friction and wear volume of copper-impregnated metallized carbon/stainless steel and pure carbon/pure copper couples are lower. Therefore, both friction couples are appropriate for pantograph strip/contact wire couple.
Large-Area P-μc-Si:H Thin Films Prepared by VHF-PECVD and its Application in Micromorph Tandem Solar Module
Authors: Ren Hui Zhi , Zhao Ying , Zhang Xiao Dan , Ge Hong , Wang Zong Pan
Published: October 2011

Superscript textHigh conductivity,high crystalline volume fraction p-type microcrystaline silicon(p-μc-Si:H) thin films prepared by high-pressure VHF-PECVD are reported in this paper．The effects of the boron concentration, the silane concentration and the plasma power on the microstructures and electrical characteristics of P-μc-Si:H thin films are investigated. The results show that the microstructures and electrical characteristics of thin films relied on the deposition parameters. By optimizing the deposition parameters, very thin(31 nm) P-μc-Si:H thin films have been obtained at the doping ratio of 0.4% , SC at 1.2% and power at 1800W. The Xc of P-μc-Si:H thin films was 67% with 4.3% uniformity ,the dark conductivity was 0.68S/cm with 5.1% uniformity. By employing this P-μc-Si:H thin films, an initial conversion efficiency of 8.12% was obtained for a 0.79 m2 a-Si:H/μc-Si:H tandem module by Al as back reflector.
Pre-Warning and Decision Making of Water Breakthrough for Higher Water-Cut Oil Field
Authors: Jiang Han Qiao , Wang Shuo Liang , Zhang Yuan
Published: October 2011

Major domestic oil fields have entered the period of high water now, however, choosing timing of profile control and water shutoff is always delay, Mostly have to wait until after the adoption of dynamic degradation. This article introduced the concept of early warning that is widely used in military and economic fields to profile control and water shut-off decision-making in high water-cut stage. Combination of actual situation of water shut-off decision-making, Presented a strong adaptive set of Warning signs of indicators, on the basis of the analysis of variation in the warning sighs of indicators, this paper proposed early warning model and processes of profile control and water shut-off. The model not only can give the current degree of a single well, but also can forecast the future degree of change in a period of time, so this modle could provide an effective basis for water shutoff and profile controle decision-makers.
Numerical Analysis of the Second Composite Ground
Authors: Wang Shu Li , Chen Dun Wu , Wang Ran
Published: October 2011

The behavior of a foundation built on normally consolidated soft soil reinforced with stone columns (SC) and deep mixing columns (DMC) is studied using a finite element analysis program, Phase2D. The numerical predictions are analyzed in terms of absolute vertical displacement, absolute horizontal displacement, mean stresses, volumetric strain, maximum shear strain and strength reduction factor. Firstly, the effectiveness of the use of stone columns, the first composite ground, is studied. Afterwards, because load bearing capacity is less than 160 kPa designed, the effectiveness analysis reinforced with DMC, the second composite ground, is performed to study the influence on the soil-columns system of the foundation and columns.
Study on Preparation of Modified Nano-TiO2 and its Application in Photocatalytic Treatment Wastewater Containing Cd2+
Authors: Yu Xiao Cai , Zhu Peng Fei , Chen Yue Xia , Wang Jun , An Zong Fu
Published: October 2011

Nano-Sn0.25Ti0.75O2 was prepared with hydrothermal method using tetrabutyl titanate as one of the primary raw materials. The products were characterized by XRD and SEM, which revealed that the crystal structure of Sn4+-doped nano-TiO2 is rutile, and the nanoparticles diameter was 14.49nm. Photocatalytic treatment the machining wastewater containing cadmium ions with the UV excitation by Nano-Sn0.25Ti0.75O2 was investigated. The experimental results show that Nano-Sn0.25Ti0.75O2 can be used as photocatalyst to removal Cd2+ from the wastewater effectively with the UV excitation. The wastewater pH value, the initial concentration of Cd2+, the amount of catalyst，the reaction time and other factors affect the efficiency of photocatalytic treatment significantly. The optimization experimental conditions for photocatalytic treatment wastewater containing cadmium ions are as follows, when the concentration of Cd2+ in the wastewater is 20mg/L, amount of Sn0.25Ti0.75O2 is 2g/L, pH in wastewater is 7 and the photocatalytic reaction time is 2h, the removal rate of Cd2+ from the wastewater is up to 98.4%.
Combustion Properties of Mixed Biomass Fuel in Thermogravimetric Analyzer
Authors: Zhang Han Fei , Du Guo Qin , Dong Qiao Hong , Lv Cai Xia , Shi Si Mo , Dong Chang Qing
Published: October 2011

Thermogravimetric analyzer has been employed in this paper to test the combustion properties of four kinds of mixed biomass fuel with sludge, domestic waste, swill, coal and grass as major components. Combustion characteristic parameters were obtained through series of experiments, and burning activation energy was got by kinetic analysis. Research results show that ignition temperature of mixed biomass fuel was relatively low and the mixed biomass fuel could be burned easily. The calculated burnout characteristics index and combustion characteristic index showed that combustibility of sample A is the worst while sample D is the best among four materials. Combustion kinetics calculations about the four samples showed that average activation energies for A, B, C and D under the low and the high combustion temperature are 47.02 kJ/mol and 50.51 kJ/mol, 28.10 kJ/mol and 26.98 kJ/mol, 27.93 kJ/mol and 26.72 kJ/mol, and 23.26 kJ/mol and10.73 kJ/mol, respectively, which present the order of activity: D>C>B>A. Results indicated that sample D has the best component proportion which could easily break down and burn out. Furthermore, combustion characteristic index of mixed biomass depends on the proportion of components, where the lower proportion of domestic waste in mixture, the better combustion characteristic index of mixed biomass fuel.
Solar City in China
Authors: Zhang Kun , Wang Su , Zhou Meng Ying , Xu Hai Mei , Liu Cai Chi
Published: October 2011

This article introduces examples of solar cities, such as the Sutton Beddington Community in United Kingdom and the Abu Dhabi City in United Arab Emirates. Meanwhile, the spate of solar city is described in detail. The most important, we point out the confusion of China's solar cities development.
Single-Phase Grid-Connected PV System Based on Multi-Carrier PWM and Power Feed-Forward
Authors: Zhang Qin Jin , Liu Yan Cheng , Wang Chuan
Published: October 2011

In the traditional single-phase grid-connected photovoltaic(PV) system, the output grid-current has the shortcomings of high harmonic distortion rate and slow dynamic response. In order to solve these problems, an improved method on the inverter is proposed. The inverter consists of full-bridge circuit and auxiliary circuit. With the multi-carrier PWM, the inverter produces output voltages in five levels, which can reduce the THD of the grid current. At the same time , this paper presents the power feed-forward algorithm based on traditional control method. The output power of PV array is added to the reference of current close-loop as power feed-forward, which improves the dynamic response to the input power changes. At last, the simulation results show the effectiveness of the proposed method.
Running Strategy Optimization of Micro-Cogeneration System in Residential Building
Authors: Liu Qing Rong , Ruan Ying Jun , Ren Jian Xing
Published: October 2011

This paper optimizes the running strategy of residential cogeneration system, through discussing the introduction effect of a hypothetical cogeneration system for a detached house. Based on the seasonally electricity and thermal load characteristics, several annual running strategies were set considering the cogeneration equipment’s efficiency (electricity generation and thermal recover efficiencies). By simulating hourly operation condition, the yearly energy consumption, CO2 emission and energy cost were discussed. Then, the effect of running strategy were evaluated in the view of energy saving, energy cost and environmental effects. Analysis results is that the optimal running strategy is different for different co-generation equipment’s efficiency, and then the running strategy design should considering not only energy demand but also the equipment’s efficiency performance for residential cogeneration system.
Liaoning Province Molybdenum, Rare Earth and Mineral Resources Exploration Situation and Demand Forecasting
Authors: Zhai Fu Rong , Yang Zhan Xing , Pan Yu Qi
Published: October 2011

The liaoning province is big province of mineral resources, although some energy and nonmetallic minerals resource reserves have among the top, but the rare earth provide strategic significance of mineral resources is the shortage, and molybdenum resources reserves to reduce year by year. This article through the objective analysis of molybdenum in liaoning province, the rare earth mineral resources exploration, status quo and the existing main problems of rare earth mineral resources, the province of molybdenum and long-term forecast the recent demand, in the province of mineral resources planning, provides the basis.
Application of PV Window for Office Building in Hot Summer and Cold Winter Zone of China
Authors: Guo Wen Wen , Qiu Zhong Zhu , Li Peng , He Jia , Zhang Yi , Li Qi Ming
Published: October 2011

In this paper, three kinds of PV glazing system applied to office building of Shanghai which located in hot summer and cold winter zone of China were studied. Building simulation software Energy Plus was used to simulate thermal load, lighting electricity consumption, and PV electricity generation. According to the simulation results of annual electricity consumption, taking SC as the comparison basis, the saving rate of single PV glazing system (SPV) was 3.6%, double PV glazing system (DPV) was 4.8%, and natural-ventilated PV glazing system (NVPV) was 6.7%.
Studies on Treatment of Simulated Printing and Dyeing Wastewater on Titanium Electrode Coated MnO2 Doped with Ce
Authors: Zhou Xiao Lv , Tan Xiao Wen , Li Huan , Shang Fei
Published: October 2011

Experiments on treatment of simulated printing and dyeing wastewater by prepared titanium-based electrode coated manganese dioxide doped with cerium were carried out in this paper. Factors such as current density, electrolyte concentration, solution pH value, electrolysis time, initial concentration of simulation printing and dyeing wastewater on the effect of treatment were also investigated. It is showed that: utilizing the self- prepared electrode to treat printing and dyeing wastewater in optimized conditions, which current density is 30mA/cm2, electrolyte (sodium chloride) concentration is 0.1 mol/L, electrolysis time is 80min, and pH is 9, 92% and 97% of CODcr and color removal were achieved, respectively.
Research on Multi-Stage Series-Connection High-Voltage High-Power Matrix Converter
Authors: Jiang Ting , Jiang Jian Feng , Yang Xi Jun
Published: October 2011

Charge storage is an important research topic in smart grid and distributed generation system, pumped storage as one of the most popular large-scale charge storage methods has attracted increasing attention. However, the motor generator of the pumped charge station has high input voltage and heavy load, so in order to get grid connected safely, being soft started by a high voltage converter is necessary. In the view of the existing high voltage high power converters, only the voltage source inverter Multi-stage Series-connection high voltage frequency converters are suitable for this application, and this paper gives analysis of such converters. Based on Carrier Wave Phase-Shifted modulation, this paper proposes a multi-stage Series-connection high voltage frequency converter with balanced output power of the step-down transformer’s secondary windings, in which a winding burdens three symmetry three-phase to single-phase MC outputs, and the same phase outputs of the MC are cascaded at the secondary side of the transformers, letting out one phase of high-voltage AC output. The circuit is consisted of a step-down industry frequency transformer at the network side, three-phase to single-phase MC arrays, a step-up high frequency transformer at the load side and filter components. The simulation result based on MATLAB/SIMULINK shows that the proposed multi-stage Series-connection high voltage frequency converter is feasible and low-cost.
Mechanical Characteristic of Buffer/Backfilling Materials After Different Temperatures
Authors: Yan Ming Qing , Yi Fa Cheng , Zhu Bao Long
Published: October 2011

Based on uniaxial compression test, the mechanical properties of buffer/backfilling materials after different temperatures are studied. The study analyzed buffer/backfilling materials of stress-strain curve，peak stress，modulus of elasticity，peak strain, with the variation of temperature. The buffer/backfilling materials of strengthening and degradation in different temperature are discussed briefly. The test result show that below 200°C, buffer/backfilling materials of stress-strain curve of slope，peak stress，modulus of elasticity，peak strain ,are increase with increasing temperature increase. The main reason is that with increasing temperature, adsorbed water in the sample will evaporate, and brittleness of sample will improve; mineral particles of expansion lead to the original cracks closing, the porosity will reduce, and improve friction properties between particles. 300 °C,buffer / backfill materials of stress - strain curve of slope, peak stress, elastic modulus, decreased to varying degrees compared to 200 °C. the main reason is that thermal stress damage to the internal structure of the samples, resulting in new small cracks. The peak strain of buffer / backfill materials in the 25 °C～100 °C is increase with increasing temperature increase.100°C～200°C, peak strain is decrease with the increase of temperature. In the 200 °C～300 °C, the peak strain change little.
Research on Nanocrystalline Silicon Film Solar Cells
Authors: Xue Chun Rong
Published: October 2011

Nanocrystalline silicon film has become the research hit of today’ s P-V solar technology. It’s optical band gap was controlled through changing the grain size and crystalline volume fraction for the quanta dimension effect. The crystalline volume fraction in nc-Si:H is modulated by varying the hydrogen concentration in the silane plasma. Also, the crystallinity of the material increases with increasing hydrogen dilution ratio, the band tail energy width of the nc-Si:H concurrently decreases. Two sets of nc-Si:H solar cells were made with different layer thicknesss, their electronic and photonic bandgap, absorption coefficient, optical band gap, nanocrystalline grain size(D), and etc have been stuied. In addition, we discussed the relationship between the stress of nc-Si thin films and H2 ratio. At last nc-Si:H solar cells have been designed and prepared successfully in the optimized processing parameters.
Study on Forest Tourism and County Economy by Grey Correlation Analysis - Taking Six Counties Eastern Liaoning as a Case
Authors: He Dan , Chen Ke , Zhai Yin Li
Published: October 2011

This paper uses the theory of grey relational analysis to calculate the correlation between forest tourism and three industrial sectors in Eastern Liaoning from 2000 to 2009. The conclusion is that the forest tourism has remarkable effect on tertiary industry. The author further discusses the coordination of forest tourism and sub—industries and draws a conclusion: warehousing and transportation, hotels and catering services are most closely related to the forest tourism. At last, this article proposes the suggestion of industrial restructuring in rich forest areas.
Reliability Assessment of Composite Generation and Transmission System with Wind Farms
Authors: Jiang Wen , Hu Zhi , Yan Zheng
Published: October 2011

Wind energy will affect the reliability of power system for its randomness and fluctuation. In this paper, the steady state model for the asynchronous generator is established and wind farms are considered as special PQ buses during power flow calculation. Combining with state models of conventional generating units, transmission lines and transformers, a time-sequential Monte Carlo simulation based on wind farm reliability model is established to do reliability assessment of composite generation and transmission system with wind farm. Meanwhile, an optimal load shedding model is used to decrease shedding load. IEEE-RTS test system is used to prove the proposed method. Analysis and comparison of results show that reliability can be improved clearly after integration of wind farm.
Investigation on the Wall Circulation Characteristic of Boiler under Solar-Coal Complementary Electric Generation Condition
Authors: Yin Li Bao , Song Jing Hui , Wen Zhi Yong , Cui Zheng Dong , Yu Yue Xi
Published: October 2011

Utilizing multi energy sources synthetically is one of the trends of energy utilization. China has splendid solar energy resource, however, the majority of the electricity production still comes from coal-fired power plants. It is of great necessity to investigate the solar-coal complementary electric generation technology. A 300MW unit thermal-circulation boiler has been studied; calculations about the wall circulation characteristics have been made under 40 conditions. The influence of solar-energy utilization on wall circulation has been analyzed. Calculation and analysis indicated the following: the utilization of solar energy has prominent influences on the steaming point and the under-heating condition of the drum water; the solar energy could be used at high load or low load with the high pressure heaters bypassed conditions, but should not used at 60%-70% load.
Adsorption of Sn (II) from Aqueous Solutions on Expanded Graphite
Authors: Yang Ming , Zhao Ying Hua , Zhang Ying Chen , Li Deng Xin
Published: October 2011

Expanded graphite (EG) was prepared by microwave irradiation at 1000 w for 60 s. It is a novel adsorbent for Sn (Ⅱ) adsorption. This paper aims to investigate the effect of the adsorption of EG. The adsorption behavior of Sn (Ⅱ) from aqueous solution onto EG was investigated with variety of parameters such as pH, adsorbents dosage, initial Sn (Ⅱ) concentration, contact time and temperature. On conditions that the pH was 2.5, the dosage of adsorbent was 0.02 g, the concentration of Sn (Ⅱ) was 200 mg/L and the temperature was 15°C, the maximum removal rate can reach to 98.32%, and the adsorption quantity can reach to 245.7985 mg•g-1. The results showed that the EG was an efficient and novel adsorbent for the removal of stannum from aqueous solution.
Numerical Simulation Study on Heat Pipe Cooling System of Proton Exchange Membrane Fuel Cell
Authors: Sun Shi Mei , Zheng Li Qiu
Published: October 2011

The paper which based on transferring heat problem of fuel cell , applying the new heat pipe cooling system and established math model of proton exchange membrane fuel cell , proved factors that affecting heat pipe and the fuel cell cooling. Showed that: cooling fluid temperature, hot and cold length ratio, gas pressure and diffusion layer thermal have a significantly affect to fuel cell.
Research on System Structure of Renewable Resource Micro Power Grid Distributed Independently
Authors: Zhao Yun Peng , Cheng Zheng Qing , Li Nan
Published: October 2011

The paper discusses and studies the system structure and management characteristics of the micro power grid, which is constructed by renewable resource and distributed independently in a small area. Aiming at several presently existing system structure of micro power grid, the article makes some analysis and contrast. At one time, the article discusses the structure and the core stability problem of the micro power grid and brings out the net criterions adapting to the structure of distributed micro power grid.
Numerical Simulation of the Supersonic Planar Mixing Layer
Authors: Gu Jin Liang , Zhang Huan Hao , Chen Zhi Hua , Jiang Xiao Hai
Published: October 2011

Large eddy simulation (LES) has been used to simulate both non-reacting and reacting supersonic planar mixing layers at convective Mach number Mc=0.3. The different eddy characteristics of two cases have been visualized and discussed based on our calculated results, and the differences of mixing layer structures have also been shown, which can provide some important guide for future relative engineering design.
Fluctuating of Chemical Reaction Progression Variable
Authors: Zou Qing Hua
Published: October 2011

Abstract: The paper derived and gave the mean square deviation formula relating to the internal variable (chemical reaction progression variable) fluctuating of the linear non–equilibrium local system, and also rendered the condition of the stability. Furthermore, It discussed the related relations among the corresponding mean square deviation, the detailed equilibrium equation, the relax time and other thermal mechanics variables.
Effect of Heat Treatment on the Crystal Structure and Optical Band Gap of Cigs Thin Films
Authors: Han Lei , Ding Tie Zhu , Wang Yan Lai , Chao Luo Meng , Shang Tao
Published: October 2011

The CIGS thin films were prepared on ordinary soda lime glass substrates by pulsed laser deposition (PLD). The XRD and UV-visible spectrophotometer has been determined. The influence of different heat treatment temperature on crystal structure and optical properties has been studied. The results shows that heat treatment at 450°C, the films along the (112) plane preferential grow. The thin film’s structure is integrity, the film is in best crystallization conditions, band gap is 1.35eV and the film has a high visible light absorption efficiency.
Maximum Power Point Tracking of PV Systems Using Fuzzy Controller with Boost DC/DC Converter
Authors: Liu Jun , Zhang Cheng Lin , Dong Xiu Chun
Published: October 2011

This paper presents a fuzzy-logic-controlled boost DC/DC converter for photovoltaic (PV) system . The tracking algorithm changes the duty ratio of the converter such that the PV model voltage equals the voltage corresponding to the MP point at that solar insolation. The main difference between the method used in the proposed MPPT system and other techniques used in the past is that the MPPT method is fuzzy based and is used to directly control the dc/dc converter, thus reducing the complexity of the system. The proposed fuzzy tracking effectiveness is demonstrated through the simulation results, and are compared with the conventional controller based system.
Removal of Nickle Ion from Mariculture Seawater with Marine Microorganism
Authors: Zhang Qiu Rong
Published: October 2011

This study use purely bacteria on suitable condition, eliminate other bacteria come in life-form bacteria. Through the orthogonal experiment obtains the optimum condition of sodium alginate fossilization Sphingomonas strain pellet to nickel bioremediation, and discusses the influence of single factor to the sodium alginate fossilization Sphingomonas strain pellet to nickel adsorption, including the time, the temperature, pH, the initial adsorbent density, the speed of the shaker, the absorbent which the different periods of growth bacterium does, coexistent ion, desorption. From the research, we know the maximum adsorption rate to nickel is about 85%. Dynamics research indicated that in the several methods of the sodium alginate of nickel, the methods of embedded micro-organisms embodies much advantages ,as operating easily, effecting clearly, less pollution, costing low, etc.
Research on Thermal Management System for the Vehicle Application of Lithium-Ion Power Batteries
Authors: Zhou Fang , Zhong Yong , Zhang Pei
Published: October 2011

Thermal management technique is one of the key techniques for the vehicle application of lithium-ion power batteries. Based on the analysis of thermal characteristics of the lithium-ion power batteries, the establishment of thermal model and numerical simulation for the lithium-ion power batteries were discussed. Finally, a procedure for designing battery thermal management system (BTMS) was proposed, and the key techniques during designing a BTMS were studied, including selection of heat transfer medium, design of cooling/heating structure and so on. This research provides a technique support for designing a good and effective BTMS, as well as improving the working performance and security of the lithium-ion power batteries and the electric vehicles.
Study on method of Energy-Saving and Efficiency Improvement of Flame Proof Three Phase Asynchronous Motor for Fan
Authors: Zong Rong Zhen , Qiu Yu Jiang
Published: October 2011

All kinds of factors affecting the efficiency of three phase asynchronous motor are studied, the methods of energy-saving and efficiency improvement of flame proof three phase asynchronous motor for fan are analyzed form the aspect of calculation of electromagnetism, selection of material, design of wind path, machining process etc, the practical optimizing methods are put forward and are verified through the product. The experiment show that the efficiency of the motor designed according to this method has improved greatly. So these methods provide some reference for the design of flame proof three phase asynchronous motor for fan. Other methods that could be used to saving energy are also analyzed in theory in the paper, which offer some reference for the enterprise using mining flame proof fan to seek the method of energy-saving and efficiency improvement.
Preparation and Laboratory Evaluation of a New Type of Cross-Linking Agent for Acid Fracturing Fluid System
Authors: Wei Xiang Bo , Li Xiao Rui , Xue Xiao Jia , Ding Li
Published: October 2011

A type of zirconium-organic cross-linking agent with excellent temperature resistance and delaying performance was prepared for acid fracturing fluid system. The factors influencing on the synthetic process of the zirconium-organic cross-linking agent were investigated and the optimum condition was obtained: 5% zirconium oxychloride, 20% ligands, reaction temperature 50~55°C, reaction time 4.0~5.0h. Then the best technology for zirconium-organic cross-linking agent and the laboratory evaluation for the acid fracturing fluid system were studied. The results showed that using the cross-linking agent can obviously improve the temperature resistance, delaying performance and the shearing resistance of the acid fracturing fluid system. Meanwhile, the zirconium-organic cross-linking agent had excellent gelout performance and sand-carrying performance, which can satisfy the fracturing operation requirement for the reservoirs below 100°C.
Transformer Fault Diagnosis Based on Gene Expression Programming Classifier
Authors: Dong Zhuo , Zhu Yong Li
Published: October 2011

Gene Expression Programming (GEP), which is suitable for transformer fault diagnosis Classification, is combined with transformer oil dissolved gas analysis (DGA), and also a method of transformer fault diagnosis based on self-adaptive GEP classification algorithm is proposed. We choose 400 groups of DGA measured data which includes a variety of failure and does not redundant as the training samples and test samples of the GEP classifier. A large number of diagnostic examples show that the proposed self-adaptive classification GEP is suitable for transformer fault diagnosis, and its performance is better than using Naive Bayes (NB) classifier, BP network and Immune classification.
The Service Restoration in the Distribution System with Distributed Generators Based on the Heuristic Multi-Agent Evolutionary Algorithm
Authors: Yang Li Jun , Wang Wei Li
Published: October 2011

In view of a large number of distributed generators penetrated into distribution network, an improved hierarchical island operation was proposed to make the DG play the role as backup power supply in the service restoration of the distribution network; As the renewable distributed generators was strongly advocated, A new mathematical model was proposed to make full use of them. The service restoration problem is a constrained multi-objective optimization problem, a new algorithm which was the combination the heuristic algorithm and multi-agent evolutionary algorithm was proposed, it improved the multi-agent evolutionary algorithm with the Niche technologies to ensure the variety of the populations in the post-optimization and used the adaptive updating strategy to improve the convergence speed. The results of a case show feasibility and correctness of the model and the algorithm.
Improvement and Application of Genetic Algorithms in Reactive Power Optimization of Power Network
Authors: Lei Lin , Ge Yi Nan , Yuan Qin
Published: October 2011

Reactive power optimization that is optimized by Simple Genetic Algorithms has many limitations. According to the problem of reactive power optimization of high voltage system, the Simple Genetic Algorithms is improved. The improved algorithm is applied in reactive power optimization of IEEE-6 bus system, the results indicate that the improvement is effective and it can accelerate the convergence speed and enhance the ability of optimization.
Research on the Properties of Copper-Clad Steel in Substation Grounding Project
Authors: Li Fu Zhong , Cui Qiong
Published: October 2011

The paper firstly introduces the situation of our substation grounding system. The author based on resource conservation to point out the necessity and urgency to promote the efficient material. Then, from the aspects of technology properties and technical performance, profound comparison is made between copper-clad steel and traditional conductors. Last but not least, in order to analyze objectively, the paper based on a real 500kV substation to discuss from the point of economic properties. All testify that copper-clad steel indeed a perfect grounding conductor.
The FrameWork of Voltage Stability in Multi-Infeed AC/DC Power System
Authors: Yan Chang You , Bu Guang Quan , Sun Hua Dong
Published: October 2011

This paper first introduces the concepts( SCR, ESCR, QESCR ,H, and VSF.) and their usage. Later MIIF, equivalent admittance, MISCR and MIESCR, PBR are detailedly expounded. This paper put forward to the steps of the primary steady voltage stability work , detailed scheme of the steady voltage stability, the studing methods of the transient voltage stability in the multi-infeed AC/DC system. At last, the online voltage stability and the virtual smart power grid were put forward.
The Research on the Method of Feature Selection in Support Vector Machine Based Entropy
Authors: Zhu Xiao Yan , Tian Xi , Zhu Xiao Xun
Published: October 2011

The large rotating machinery functioning of the rotor is one of the most important issues. It has great significance to identify the fault early and implement intelligent fault diagnosis. However there is a big nonlinear about large rotating machinery and has less fault samples. This led great difficulties for feature selection and state recognition. Based on Entropy in feature selection, we extract each intrinsic mode’s function energy as eigenvector and make them for input parameter of the support vector machine (SVM) to fault diagnosis. The experiment shows that this method can classify the fault state, and completed intelligent fault diagnosis.
Sources and Treatment of the Particulate Pollutant in the Transformer Oil
Authors: Xie Xue Jun , Fu Qiang , Zou Pin Guo , Su Wei , Xiao Tiao Bing , Wang Meng Jun , Lu Guo Hua , Wei Zeng Fu
Published: October 2011

The definition and the sources of the particulate pollutant in the transformer oil were described in the article. The prevention and elimination of the particulate pollutant were introduced as well.
Laser-Triggered Surface Flashover Characteristics of Al2O3 in Pulsed Voltage
Authors: Pan Ru Zheng , Wang You Hua , Li Min Tang , Pang Ling Ling , Wang Jue , Yan Ping
Published: October 2011

Based on the platform of laser-triggered surface flashover in pulsed voltage, experiment of laser-triggered surface flashover is carried out in air and vacuum condition with pulsed voltage. A single/double harmonic, with wavelength of 1064/532 nm, Q-switched Nd:YAG laser is applied to trigger the surface flashover. The test system consists of flat electrodes and columned insulator. The material of electrode is copper and the material of insulator is Al2O3. Laser pulse’s wavelengths are 532nm and 1064nm, and laser is focused with rectangle. The results of experiment show that flashover delay time and jitter time decrease with increase of pulsed voltage or laser energy density, the delay time of 1064nm laser trigger is larger than that of 532nm laser trigger, and the delay time and jitter time in vacuum condition are less than the delay time and jitter time in air condition.
Analysis of Urea Solution and Experimental Study for Adaptability of SCR Converter in Vehicular Diesel Engines
Authors: Wang Qian , Qi Ping , Han Xiao Jing , Zhou Ming Xing
Published: October 2011

In this paper, the Urea-SCR system is first introduced; then change of the urea solution concentration under different temperatures with time lapsing is given. Meanwhile, conditions for the urea crystallization are analyzed and SCR converter adaptability is tested under high sulfur environment on engine test bench. As the efficiency of NOx conversion is not significantly reduced after aging and the activity of the catalyst is very little damaged by dense sulfur content in fuel, SCR catalyst is able to adapt to the application of high-sulfur-contained fuel environment in our country.
Heat Transfer in Narrow Rectangular Channels with Rib Turbulators
Authors: Liu Jia Zeng , Gao Jian Min , Gao Tie Yu , Shi Jiao Jun
Published: October 2011

An experimental study of heat transfer characteristics of narrow rectangular channels with rib turbulators for Re in the range of 10000-60000 was performed. To simulate the actual geometry and heat transfer structure of blade/vane internal cooling passage, each of the test channels was welded by four stainless steel plates. Because of the three dimensional heat conduction in the walls and heat conduction between the ribbed and smooth walls, the measured temperature distribution along the axial direction of the test channel is a smooth continuous curve, and when the Re is low, the average Nu of the ribbed and smooth walls are nearly the same. For each aspect ratio channels, the average Nu for the channel of α=45° is about 15 to 25 percent higher than that of α=60°. In addition, we have developed the semi-empirical correlations, covering the range of Re, to predict heat transfer coefficient of the channels. The correlations can be used in the design of turbine blade/vane cooling channels.
Reliability Prediction of Products Based on Generalized Closeness Degree
Authors: Li Ling Ling , Zhao Chun Tao , Huang Shan Shan , Li Zhi Gang
Published: October 2011

In practice, the getting product data types have ordinary real number, interval-valued in real number field, fuzzy set in real number field. In order to dispose these data simultaneously, a new generalized closeness degree is proposed in this paper. And then make it applied to reliability prediction. The new generalized closeness degree is getting through the weighted fusion with two of commonly used closeness degree. lattice close-degree Based on membership degree, and measure close-degree Based on area ratio. According calculating the characteristic factors’ close-degree between the awaiting predicting product and the case products, for every attribute value distributing a weight, prediction result is obtained by integrating the data.
Measurement of Harmonic Impedances of Supply Systems Using Natural Disturbances
Authors: Jia Shan Jie
Published: October 2011

This paper presents a novel and practical method for monitoring harmonic impedances of power systems seen at load serving substations. The method uses the natural load fluctuations measured at the substation for impedance estimation. It avoids the needs for intrusive disturbances and can be used for online tracking of impedance parameters. The method has been verified through several real field measurements.
Co-Biodegradation of Multiple Monocyclic Phenolic Compounds by a Novel 2,3-Xylenol-Degrading Pseudomonas Isolate
Authors: Xiao Zi Jun , Qi Rui Qian , Huo Fang Fang , Huang Yun Ling , Xu Hai , Lu Jian R.
Published: October 2011

Monocyclic phenolic compounds (MCPCs) from petroleum and coal sources mainly include phenol, cresols, and xylenols. A newly isolated 2,3-xylenol-degrading strain,Pseudomonassp. XQ23, was found to be capable of degrading up to 10 MCPCs for the first time. Addition of easy-to-degrade MCPCs such as phenol and cresols helped decompose hard-to-degrade xylenols and the sequential digestion of the phenolic substrates was highly dependent on their molecule structures. The action on multiple MCPCs by the new isolate XQ23 from this work revealed useful clues on the co-biodegradation of multiple pollutants.
The Studies on the Esterification of Oleic Acid Using P2O5/CaCl2/Fe3O4 Composite Catalysts
Authors: Di Xiao Wei , Li Nalingaova , Zhang Jun
Published: October 2011

P2O5/CaCl2/Fe3O4 composite catalysts for the esterification of oleic acid was proposed. Optimum conditions for the esterification of oleic acid to produce methyl ester of oleic acid were investigated which yielded a maximum conversion of oleic acid to the methyl ester. The variables were: 1) temperature and time of reaction; 2) amounts of catalyst and 3) ratio of alcohol to fatty acid.
A Grid-Connected Control Strategy of NPC Three-Level Inverter for Direct-Driven Type Wind Power Generator
Authors: Qu Ke Qing , Xing Yue Hong
Published: October 2011

Based on the mathematical model of the wind power grid-connected inverter, the proposed space vector PWM current control and double current control realize the decoupling for the current active component and reactive component. The simulation results show that the system can output three phase sine current which meet the requirement of the gird-connected, and the harmonic component is low.
Research on Minimum Switching Losses of Three-Level PWM Rectifier
Authors: Wu Wen Jun , Han Xiao Ning , Zhong Yan Ru
Published: October 2011

In this paper, the pulse width modulation based on double reference signals is proposed for diode neutral point clamped tri-lever rectifier. In this method, the angle of non-switching region is chosen to make switching losses minimum, and DC voltage utilization is improved. The simulating results show that proposed strategies are correct.
Design of Main Parameters for the Main Circuit of Soft-Witching Inverter
Authors: Wu Dong Chun , Tian Song Ya
Published: October 2011

To meet the demand of that the waveform control welding machine controlling the waveform of the arc voltage and arc current, need to further improve the working frequency of the inverter power source and reduce switching loss, switching stress and electromagnetic interference. The parameters of soft-switching inverter’s main circuit, witch make the working state with zero-voltage and zero-current switching, is designed. First, the working principle of the FB-ZVZCS-PWM inverter is analyzed. And the constraint equation of the main circuit’s parameters is obtained, it provide the basis for the calculation of the main circuit’s parameters. According to the requirements of the working condition of inverter and the time sequence of PWM, the value of the block capacitor Cx is obtained. And the satiable inductor, witch improve the rise speed of the short circuit current and the descending speed of the necking current, is designed. Second, the simulation model of the satiable inductor is designed. And the simulation model of the FB-ZVZCS-PWM inverter is established. It verified the correctness of the theoretical analysis and the parameter design.
Modeling and Simulation of Single Phase Inverter with Dynamic Phasors
Authors: Gu He Rong , An Shao Cong , Zhao Wei , Guo Xiao Qiang
Published: October 2011

The power electronic devices are difficult to model due to their switching behavior. Conventional quasi-static models are difficult to reflect the dynamic behavior of the switching adequately. Electro-magnetic transient analysis based on time-domain models can offer improved accuracy, but their nonlinear time-varying nature is impractical to analyze the large power system. A model for single phase inverter on the basis of dynamic phasors is established in order to improve the accuracy of simulation and reduce computation. By comparing the dynamic phasor (DP) model and the detailed time domain electromagnetic transient (EMT) model of single phase inverter, the simulation results show that the DP method could ensure simulation accuracy and reduce computational cost.
Nonlinear Lyapunov-Based Stable Control Method of the Single-Phase Shunt Active Power Filter
Authors: Li Lan Fang , Yang Hong Geng , Guo Wei Ming , Liu Ya Mei , Xu Fang Wei , Gong Wei
Published: October 2011

This paper proposes a nonlinear Lyapunov-based control method of the single-phase shunt active power filter (APF). The system is modeled firstly and then the compensated current of the APF is calculated. The energetic like Lyapunov function is constructed and the control output is determined through ensuring the differential of the Lyapunov function negative, which grantee the convergence of the APF system. Considering that the time-varying load may cause greater fluctuations in DC voltage, an average value is used to calculate the control output. A globally stable control is possible and it is insensitive to the parameter uncertainties and robustness to the disturbances. Simulation results are obtained using Matlab/ Simulink. These results verify the correct operation of the proposed control method.
Investigation on the Combustion Properties of Refuse Derived Fuel in an Internally Circulating Fluidized Bed
Authors: Liu Dian Fu , Zhu Fang Qing , Wei Xiao Lin
Published: October 2011

An internally circulating fluidized bed (ICFB) was applied to investigate the behavior of refuse derived fuels (RDF) incineration. The temperature distribution along bed height was measured by the thermocouple and the pollutant emissions in the flue gas were measured by Fourier transform infrared spectrometry Gasmet DX-3000. In the tests the concentrations of the species CO CO2 HCl N2O SO2 were measured online. The experimental results showed that the RDF could combust steadily in the fluidized bed. The concentrations of the CO HCl N2O in flue gas were higher than the values of national environmental standards.
The Optimal Selection Investigation on Flame Holder for Afterburner
Authors: Tang Wen Hua , Qian Ren Zhang , Zou Huai Yu , Pi Bo Ming
Published: October 2011

In order to determine the bluff body and slitted bluff body flame stability and combustion performance, atmospheric low-speed experimental platform was used to carry out diesel fog combustion experiment for two types of bluff body, which are respectively streamlined V-form added straight channel and triangle V-form added straight channel. Results have shown that flame stability and combustion efficiency of streamlined bluff body is orderly slit width at 13mm, 6mm, 0mm and the triangular bluff body is orderly slit width at 6mm, 13mm, 0mm. Optimal combustion performance is streamlined bluff body with slit width 13mm.
Nanofiber Sheets with the Superabsorbent Properties
Authors: Martinová Lenka , Lubasová Daniela
Published: October 2011

The new electrospinning technology NanospiderTM offering a realistic potential for industrial production was used for creation of nanofiber sheets from aqueous solutions of partially neutralized poly(acrylic) acid with crosslinking agent. Produced nanofiber sheet was crosslinked by heat treatment. Absorption capacity and rate of absorption were tested and compared with superabsorbent particles and commercial superabsorbent fibers. The morphology of electrospun fibers was observed using a scanning electron microscope (SEM). Possibilities of fiber diameter influence were studied.