bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation, Purification and Identification of Antioxidant Peptides with Bienzyme Hydrolysis from Rice Bran Protein
Authors: Mei De Jun , Yu Guo Ping , Sun An Min
Published: December 2012

The rice bran protein (RBP) was then hydrolyzed with various proteases (papain, flavorzyme, neutrase, protamex, and trypsin) to prepare antioxidant peptides. The rice bran protein hydrolysates (RBPH) were assessed using method of DPPH radical scavenging ability. Hydrolysate prepared with papain and flavorzyme (activity ratio 1:1) was found to have the highest antioxidant activity (IC50=6.778±0.21 mg/ml). This hydrolysate was purified using ultrafiltration, RBPH-III (Mw＜3KDa) had the highest DPPH and hydroxyl radical scavenging activity (IC50 value of 6.56±0.28, 5.43±0.22, respectively) and highest reducing power activity (1.02±0.18 at 4 mg/mL). Later, RBPH-III was fractionated by SP-SephadexC-25 cation-exchange column into six fractions (A–F), fraction F with the highest DPPH scavenging activity, was then separated by size exclusion chromatography on a SephadexG-25 into three major fractions (F1–F3). Fraction F2 exhibited the highest DPPH scavenging activity was choose to fractionate by reversed-phase high performance liquid chromatography (RP-HPLC), seven antioxidant peptides were isolated, The F2-5 peptide displayed the highest DPPH radical-scavenging activity (58.2±1.63%; at 250 μg/ml) among these peptides, the amino acids composition of F2-5 was determined, which might play an important role on its antioxidant activity. In addition, purified peptide did show remarkable inhibition rate on SGC-7901 cells proliferation, and it also revealed the dose-dependent relationship. The results of this study suggest that rice bran protein hydrolysates are good source of natural antioxidants.
Study on Assessment of High Temperature and Humidity in Working Environment on Human Health
Authors: Sun Yu Ping , Zhu Neng
Published: December 2012

In this study, a series of references on human physiology and psychology response to hot and humid environments were analyzed. On basis of the thermo metabolism system, energy metabolism system, cardiovascular system and respiratory system, impact mechanism of high temperature and humidity on human health was presented. The results indicate that the high temperature and humidity in working environment have significant impact on human health. The high temperature and humidity cause the reducing of temperature difference in vitro and in vivo, the difficult of metabolic heat diffusion, the significant increasing of energy metabolism and oxygen consumption, heart failure, hypoxia and other physiological responses.
The Concept and Types of Human Climate Migration from the Perspective of Climate Risks
Authors: Chen Shao Jun , Cao Zhi Jie
Published: December 2012

The climate change issue and the real or potential substantial climate migration arising from climate change and its adverse impacts have become a severe challenge for human society in the 21st century, and one of the core concerns of human society today. Through the analysis of the climate migration phenomenon arising from various climate risks during the course of social development, and the conceptual definition and classification of climate migration, this paper aims to strengthen our understanding and perception of climate migration, and further grasp the essence and law of evolution of climate migration, so as to make a preliminary exploration into how to tackle the challenge of climate migration arising from climate change, mitigate social risks facing climate migration, and promote the benign operation and balanced development of society effectively.
A Novel Ranking Procedure Based on Risk Percentile Index and Concentration (rrpic) of Chemicals
Authors: Chen Fu , Liu Shu Shen
Published: December 2012

Assessments of the relative risks posed by chemicals are needed to assist in the development of management plans that minimize ecological impacts. A procedure scoring and screening chemicals entitled ranking procedure based on risk percentile index and concentration (rrpic) was developed based on inherent physico-chemical properties and toxicity as well as detection concentration. The properties and toxicity were transformed into risk percentile indices (rpi) and the rpi was then used to calculate risk score (rs) by multiplying the detection concentration. Using Hasse diagram, the chemicals having different rss were classified into several rank levels. The averaged rank (rav) of each chemical was calculated by using Local Partial Order Model (LPOM) and the risks of chemicals were arranged in a linear order. The rrpic was employed to scoring and screening 31 chemicals detected in Taihu Lake of China.
Children’s Health Risk Assessment of Lead Exposure
Authors: Zou Bin , Wang Min , Luo Yan Qing
Published: December 2012

Increasing studies in China are assessing the soil Lead (Pb) levels due to its adverse health effects. However, few of them directly focus on the Pb related health risk, especially on those susceptible children living in the urban industrial park. This study evaluated the health risks of Pb-exposed children in an industrial park of XX City using the IEUBK model. Results show that the excessive Pb concentrations existed in few sampling points and the maximum Pb concentration is 1.35 times more than the second level of Soil Environmental Quality Standard of China (SEQSC). Meanwhile, the difference of the Pb-exposed health risks for children under two scenarios (with or without Pb polluted vegetables intake) is 14.61%. It can be concluded that the health risk of Pb-exposed children in study area is unacceptable and the risk might be predominantly attributed to ingestion of vegetables.
Case Study on Sewage Treatment Measures of Technical Reform Project in a Company
Authors: Sun Xu Hong , Zhou Jin Qian , Liu Yan , Zhao Peng
Published: December 2012

This paper analyzed various water pollutants, their emissions and emissions concentration depending on the Environmental Impact Assessment (EIA) of Technical reform in an electrical company. It evaluated the capacity of implementing technical reform in this company’s wastewater treatment station and the feasibility of stability up to the discharge standard in order to find the reason Ni, one of the first class of pollutants, which was discharged by the outlets of plating factory sewage treatment facilities exceeded the standard in GB8978-1996 “Integrated Wastewater Discharge Standard”. In addition, this paper proposed a reasonable treatment program which made the drainage of the wastewater treatment station reaching the standard requirements. From this paper, it reflected the important role the environmental impact assessment played to provide a technical guidance for environmental management in the technical reform project.
Comet Assay Determine DNA Damage Baseline Level of Mollusca Hemolymph Cells in Poyang Lake and Surrounding Waters
Authors: Xu Liang , Zhou Kan , Zhou Chun Hua , Ouyang Shan , Wu Xiao Ping
Published: December 2012

Mollusc species were sampled in different sites based on pollution level in Poyang lake and its surrounding waters during withered water period (from Oct to Dec) and plentiful water period (from May to June) from 2007 to 2008. Single-cell gel electrophoresis (SCGE) was used to analyze their haemolymph cells Arbitrary Unit(AU) and Olive tailmoment (OTM) value of DNA damage in molluca. The results showed that the mean DNA damage value Jin river>Nanxin>Xiu stream in withered water period; and in Plentiful water period, Hukou>Qinglan lake>Xiyuan. Two mollusc species Corbicula fluminea and Bellamya aeruginosa have higher DNA damage value than other mussel in all sites. Comparing the DNA damage value of Bellamya aeruginosa collected in twenty sites in 2008, the highest DNA damage value was observed in Dacha lake and lowest in Xiyuan. Meanwhile, the highest DNA damage value of Unio douglasiae was recorded Chucha river from ten sites, and lowest in Xiyuan river.
Distribution and Potential Risks of Frequent HABs Off Zhejiang
Authors: Lu Jianxin , Zhou Yan , Yu Jun , Wu Jia Xing , Long Hua , Zheng Chong Ying , Zeng Gan Ning
Published: December 2012

Based on the historical analysis and statistics of HAB events from 1933 to 2008, Skeletonema costatum, Prorocentrum donghaiense, Karenia mikimotoi, Noctiluca scintillans were identified as the most frequent HAB species reported in Zhejiang Coastal areas. Risk assessment considering the intensity, scale, duration, species, in accordance with the 0.25°×0.25°partition statistics, was adopted. Conclusion could be made that the extreme high HABs risk located at area A (30.5°N-30.75°N, 122.5°E-123°E), B (29.75°N-30.25°N, 122.25°E-122.75°E), C (28.25°N-28.5°N, 121.75°E-122°E), and D (27.25°N-27.5°N, 121.0°E-121.25°E), in which Prorocentrum donghaiense has the biggest causative risk.
Research on a New Control Strategy of Multi-Energy Complementary Isolated Power System
Authors: Huang Dan , Shen Hong , Yang Xiu Yuan , Zhou Qin Yong
Published: December 2012

Aiming at a kind of multi-energy complementary isolated power system in Tibet ali area, which consists of photovoltaic (PV) station with storage device, hydro generator, and diesel generator, a new control strategy was presented. According to the power system characteristics, analyzed the new control strategy, it can realize the grid power output with zero steady-state error. In the DIgSILENT/PowerFactory simulation environment, building the multi-energy complementary isolated power system model and simulation based on the control strategy, the system can track the fast variation of the PV array output power or other output power. Two studied cases verify the control strategy.
New Voltage Sag Frequency Evaluation Method Considering the Satisfaction Degree of Sensitive Customer
Authors: He Jun , Liu Xu Na , Chen Li Ping
Published: December 2012

To meet power customers’ satisfaction is the essential responsibilities of utilities. Considering the property of customer’s satisfaction degree, an analytical interval assessment method of voltage sag is proposed. The customer satisfaction degree is presented by interval number corresponding to the voltage tolerance for the tested equipment installed at the customer side. Based on the determination function derived from the relationship between the voltage magnitude and the length of fault line in the power system, critical fault positions are determined through analytical iterative algorithm. By the variation of satisfaction degree within a given interval, the interval sag frequency is calculated. Moreover, the quantitative sag frequency is determined by the help of the interval sag frequency. The proposed method is applied to a five-bus system and IEEE 30-bus testing system. The simulation results comparing with existing methods have shown that this method is credible and suitable for the practical engineering application.
Study on a Method of Single – Phase Grounding Fault Locating for Hybrid Transmission Line
Authors: Gao Li , Shu Hong Chun
Published: December 2012

It is difficult to achieve precise fault location for hybrid transmission line of distribution network, because it has wave impedance discontinuity point. Section location is the premises of precise location. On the basis of others’ research results, the matrix algorithm of distribution network single-phase ground fault section location is improved in the paper. It makes the sparse degree of matrix is higher, computation is less. An algorithm of recovery the network topology only based on the fault description matrix is suggested when the visualization data of a line network topology is loss or the operating is in the non-visual condition. The method is applied to revise fault description matrix, so that the matrix algorithm has some fault-tolerance. The applicability and validity of the improved algorithm was verified by an illustration. The method realizes the fault section location, and the subsequent accurate fault location is presented in this paper.
Research on Closed-Loop Control System Based on Image-Signal Processing of Furnace Flame
Authors: Chen Rong Bao , Bian Jing Ci , Meng Fang Hui
Published: December 2012

Through the furnace-flame image-signal processing for power plant, effective-temperature field proportions, high-temperature field proportions, centroid offset distances, and circular degrees in high-temperature field can be all obtained. What’s more, based on the above data and related signals collected by sensors such as flame detectors as a criterion, the Kohonen’s self-organizing neural network is introduced to distinguish the states of furnace flame. Therefore, the opening incremental adjustment is proposed to achieve real-time control of furnace flame.
Study on Fault Location of Single-Phase-to-Ground for Distribution Network
Authors: Zhang Li , Yang Xiu Yuan , Ren Jun Ling
Published: December 2012

The AC-DC method (the AC method combined with the DC method) has integrated the superiority of the AC method’s easy measurement and the DC method’s reliability, so it has achieved some degree of use. The method before only took the ground resistor as the condition of combination, so it is not perfect. Based on deep analysis on the AC method’s reflect factors, this paper drew a conclusion that the reliability of the AC method is affected by the fault resistor and the line’s distributed capacitance. The paper took the impedance phase as the integration condition, using the AC method while impedance phase meets certain conditions, using the DC method on the other situation. This strategy combined the affluence of ground resistor and distributed capacitance effectively, so it can promote the application on spot of the AC-DC method.
The Partial Discharge Characteristics Study of the Insulated Copper Busbar Joint Metal Metal Protrusion Defect
Authors: Hu Xiao Meng , Liang Li Xue , Tan Zhi Rong , Zhang Liang , Li Jun Hao , Li Yan Ming
Published: December 2012

Insulated copper busbar is widely used as a new type of electrical equipment in recent years. The joint of the busbar is linked with soft connection copper belt in the field. So, it is very easily lead to the metal protrusion defect at the joint. The metal protrusion detect at joint with entity insulated copper busbar is builded in lab. The partial discharge characteristics of this defect is studied under different applied voltage and the results show that such defect has apparent polarity effect, the discharge always appears in the negative half cycle. The discharge amplitude will not be increased very much with increasing of applied voltage but the discharge frequency will be increased significantly. The results provide the basis of laboratory studies for the field testing of insulated copper busbar.
UAV Based Laser Measurement for Vegetation Control at High-Voltage Transmission Lines
Authors: Ax Markus , Thamke Stefan , Kuhnert Lars , Kuhnert Klaus Dieter
Published: December 2012

Trees which are growing beneath high-voltage transmission lines have to be cut down if the distance to the conductor rope gets too close. It is very hard to find those if only single trees are affected. Chopping simply all trees under a transmission line, which was done in former times, is not a desirable solution for environmental and economic reasons. In this paper a solution is shown which uses an unmanned aerial vehicle and a laser scanner to generate a 3d point-cloud representing the trees and the conductor ropes. Using this point-cloud the decision for cutting down a specific tree can easily be made.
A Novel Overhead Ground Wire with Winded Insulated Conductors for Ice-Melting
Authors: Lu Jia Zheng , Zhao Chun , Li Bo , Fang Zhen , Zhang Hong Xian
Published: December 2012

Serious icing on overhead ground wires threatens the safe running of power system. Common overhead ground wires are difficult to realize ice-melting. A novel overhead ground wire structure for ice-melting is proposed. Some conductors coated with insulation layer are winded around the galvanized steel wires in a special way. Ice-melting experiments are performed on the novel overhead ground wire. Experimental results show that 30 W per meter of the wire is an economic power while 40 W per meter of the wire is an effective power for ice-melting. Engineering application of the novel overhead ground wire with insulated conductors is carried out. With the light moveable de-icer, onsite experiment is performed. Under the power of 40 W per meter of the wire, a temperature rise of 10 °C is achieved in 30 minutes. The result shows that the novel overhead ground wire can meet the demands of engineering application.
Study of New Dampers for Application to Overhead Transmission Lines Groundwires
Authors: Sun Na , Liu Sheng Chun , Yin Quan , Qi Yi , Cao Dao Zhen , Zhang Li Chun
Published: December 2012

Aeolian vibration of overhead groundwires is intense in transmission lines located in flat and windy areas; which easily leads to line failure caused by material fatigue. To suppress the aeolian vibration of lines located in Hexi corridor, new dampers for groundwires were developed and configured, based upon analysis of the characteristics of aeolian vibration. Simulation tests were conducted according to the energy balance principle (EBP), and field vibration tests were also performed. The test results show that the dampers meet the requirements of the prescribed standard and the efficiency is verified. The dampers have been applied to 750kV transmission lines, and they offer easy installation, slip resistance and a satisfactory vibration suppression effect.
Structural Optimization of the GaAs-Based Resonant Tunneling Diodes
Authors: Zhang Bin Zhen , Guo Hao , Tang Jun , Liu Jun , Wang Jie
Published: December 2012

Structural optimization for the highly sensitive mechanical sensor elements was studied. Using Molecular Beam Epitaxy (MBE) technology, three different RTD structures were fabricated on the GaAs substrates. From the I-V characterizations, it can be concluded that, the PVCR of the best design is up to 6, VP is reduced to 0.41V, and then we analyzed the relationship between the device material structure and I-V characteristics, providing a reference for the better performance of RTD structure design.
Analysis of Influence to Electric Spindle Losses Caused by Carrier Ratio in Frequency Converter
Authors: Zhang Li Xiu , Xu Meng Yuan , Wu Yu Hou
Published: December 2012

Aiming at analyzing the influence to ceramic electric spindle and metal electric spindle caused by carrier ratio in frequency converter, in this paper, the time-step finite element model was built based on SPWM method. The changing law of the loss in different carrier ratios were gained by simulation. The result shows that the greatest impact by carrier ratio is solid loss, the least is core loss. The ceramic electric spindle is less impact by carrier ratio than metal electric spindle. Additionally, the corresponding carrier ratio with minimum loss in both ceramic electric spindle and metal electric spindle were found.
Fast True RMS Algorithm Using in the High-Voltage General Inverter
Authors: Yu Zhi Fei , Li Bing , Wang Wei , Qian Shi Bao
Published: December 2012

The high-voltage general inverter which has the advantage of the structure， has become the key equipment to saving energy in recent years. The inverter output current is the key variable of overload protection, over current protection and V/F control compensation, so the real-time accurate measurement of its RMS is extremely important. In this paper, the output current signals preprocess by hardware filter firstly, and then find the RMS of the current signal in the period of the waveform. Meanwhile, this algorithm belong to true RMS algorithm category, which suitable for testing harmonic current signal, and can avoid mean filter to reduce the computation time. By using this algorithm, the inverter control system provides accurate reference for overload protection reduces the systematic disoperation rate and sets the more accurate security allowance to ensure the safe operation of equipment.
Research of Intelligent Video Surveillance System Based on the 3G Technology
Authors: Ma Yong Li
Published: December 2012

Face to the questions in the traditional video monitoring system, this paper proposed the intelligent video surveillance system based on the 3G technology, developed by the embedded system. The system can realize the information transmitted through the 3G network. And the system has the function of remote real-time audio monitoring, remote viewing and download the video data acquisition, and message security alarm.
Numerical Exploration on HCCI Combustion Characteristics under NVO Strategy
Authors: Gao Yin Han , Wang De Fu , Cheng Peng , Li Hua , Wang You Kun
Published: December 2012

Homogeneous charge compression ignition (HCCI) offers high efficiency and ultra-low NOx and SOOT emissions which raises world-wide attention. A 3-dimensional CFD HCCI model has been established using STAR-CD code for combustion characteristics studies under negative valve overlap (NVO) strategy via an early closure of exhaust valve. The combustion characteristics of HCCI were investigated. Simulation results were in good agreement with the available experimental data. Studies on in-cylinder temperature and OH radical concentration showed almost the same spatial distribution when auto-ignition occurred, OH radical had higher concentration in the field of higher temperature. The φ-T maps showed extraordinarily low NO emissions and no soot emissions under HCCI combustion. It was found that OH concentration rapidly increased after the start of the combustion at 356°CA and NO emissions were formed when the temperature was high enough at 358°CA. Most of CO emissions were converted to CO2 through the main combustion.
Research on Digital Control of Tension Servo System Based on PLC
Authors: Chen Chong , Hu Guo Wen
Published: December 2012

Mathematical model of tension servo system drived by two induction motor is analyzed in this paper. Then, structure optimized of first-order active disturbance rejection control (ADRC) of tension servo system is designed. Double channels compensation of extended state observer is used to estimate and compensate the total disturbance of system, and approximate linear and determined treatment is done to the tension control system. S7-300 PLC is used as lower computer controller, while WinCC is used as upper computer monitor software, realizing all-digital control of the system. The experiments is carried on based on S7-300 PLC experimental platform and the results prove that the decoupling control of speed and tension is realized, and the control system has higher dynamic, static status and robustness performances.
Simulation of Two AC Motor Coiling Tension Control System
Authors: Chen Chong
Published: December 2012

When general PID controller appllied into multi-variable decoupling control system, its parameters are difficult to set and self-adaptability is poor. A neural network decoupling controller composed of self-adaptive PID controller and compensated decoupling network is presented, which is based on the analysis of the system model. Simulation results show that the controller designed basically eliminates the coupling effect of the tension control system and improves the dynamic and static performances.
Comparative Study on Control Strategies of Parallel Hybrid Active Power Filters
Authors: Liu Ding Guo , Shuai Zhi Kang , Luo An , Tu Chun Ming , Cheng Ying
Published: December 2012

In this paper, a comparative study on control strategies of parallel hybrid active power filters (PHAPF) is presented. A universal electric model of three different PHAPF is proposed. The principle for the harmonic current elimination of PHAPF when different control strategies are adopted is analyzed. As the performance of the PHAPF will be influenced by the fluctuation of the power system parameters, a comparative study of the influences when different control strategies are adopted is carried out. The conclusions can help in the choice of an optimal basic control strategy, and guarantee the secure operation of the PHAPF system. Experiments have been carried out to verify the validity of the theoretical analysis in this paper.
The Optimization to Control System of Desulfurization in Furnace of 300MW CFB Boiler
Authors: Kong Xiang Jie , Bai Jian Yun , Liu Li Hong
Published: December 2012

This paper contraposes 300MW CFB boiler of Shanxi certain coal-fired power plant, then optimize the control system of desulfurization and remake limestone transmission system. Collect the signal to establish knowledge base for judging starting or stalling control of feeding machine through lots of experiments. Adopt feedback control strategy to adjust the speed of feeding machine. Achieve the purpose of automatically controling the starting or stalling of feeding machine and the speed of feeding machine finally.
Research on the Control System of the Orthopedic Rehabilitation Bed to Cure Genu Varus or Valgum
Authors: Lu Jie , Li Hong Zhou , Li Guo Qiang , Zhang Xv
Published: December 2012

C8051F040 was used as the core of the control system of the orthopedic rehabilitation bed to cure genu varus or valgum. The paper designed a hardware circuit, software program of the system to realize the functions that the patients were able to regulate the bed fully independently.
A Dual-Processor Based Coordinator for Micro-Grid Control and Protection
Authors: Nan Dong Liang , Le Xiu Fan , Kang Peng Peng
Published: December 2012

With the development of micro-grid, the protection and control technologies for micro-grid have withdrawn broad attention. By analyzing the interactions between the micro-grid and the main grid, a dual-processor based coordinator is proposed in the paper. This coordinator achieves the functions of protection and control through two processors, utilizing the electrical information from the whole network, realizing the wide area data sharing and sound cooperation of the unit protection and regional control in the micro-grid. The proposed method enables smooth transition between grid-connected and islanded operation, which is adaptive to any operational modes. Implemented in a demonstrative project of the micro-grid in china, this novel method is verified to be efficient.
Distributed Network Power Flow of Distributed Generation
Authors: Yang Qi , Liu Meng Cong , Chen Ying , Bai Yun Xiao
Published: December 2012

With constrains imposed by natural conditions, the power generated from wind power, solar power and other intermittent energy system has great randomness and volatility. Thus, the impact from the intermittent energy to the system voltage and power flow is uncertainty. In view of this problem, this paper studies the characteristics of these double random variables and correlation. By using the typical probabilistic load flow and Monte Carlo simulation method, this paper poses the probability load flow adapted to the intermittent distributed generation. Finally, taking IEEE33 distribution system for example, this paper obtains the mutual relationship between the power from the intermittent distributed generation and the probability distribution of the node voltage, current distribution of each branch.
Reflections on Driving Force, Connotation and Technical Area of Smart Grid
Authors: Du Xin Wei , Li Yuan , Li Ting
Published: December 2012

With the rapid development of world economy, energy security and environmental issues become increasingly prominent. And smart grid turns into the common choice for the global power industry to respond to future challenges of power grid. Combining with the development experience and research results of smart grid at home and abroad, the paper discusses the driving force, connotation and related technical area of smart grid from the three levels of government, enterprise and users, from a new perspective to try to answer the questions: "Why should we develop smart grid", "What is smart grid", and "how to develop smart grid".
Leading the Smart Grid Revolution with UHV
Authors: Song Dan , Cao Ya Xu , Liang Zhi Rui
Published: December 2012

With the rapid development of the grid, smart grid has become an undoubted trend. World's major power companies are searching for local smart grid technologies in transmission intelligence, substation intelligence and distribution intelligence and other areas. And China is leading our own smart grid revolution with world-class UHV power technologies, both in AC and DC. Chinese UHV have suffered countless hardships on our road. The development of UHV and smart grid technologies in China and their position in the world prove that the UHV technologies line with China's national conditions. It is the road we must follow in the development of smart grid in China.
Based on the EMD and PSO-BP Neural Network of Short-Term Load Forecasting
Authors: Sha Feng , Zhu Feng , Guo Shun Nan , Gao Jian Tong
Published: December 2012

This paper proposes that based on the EMD and PSO-BP neural network of short-term load forecasting. This method will be automatically historical load sequence into several independent intrinsic mode functions (IMF) by using EMD. As the BP neural network training for a long time and easy to fall into local minimum of the shortcomings, we use genetic algorithm to optimize BP neural network algorithm replaces the traditional BP algorithm. Finally, we use the BP neural network optimized separately for each IMF component for training and prediction. We should add the component to the final prediction forecast. This method has higher precision than the EMD-BP model prediction by Simulation results show.
The Applications of Wireless Sensor Network in Smart Substation
Authors: Li Yang , Zhang Yi Ying , Gao De Quan , Cao Jin Ping
Published: December 2012

The electrical substation consists of many smart devices to monitor operating environment or control power facilities etc., which requires various sensors, such as temperature and humidity sensor, SF6 sensor etc, to organize as a wireless sensor network (WSN) to cooperate for intelligent operation. In this paper, we design an architecture of WSN for the smart substation, and introduce the applications in detail, including the temperature, humidity, waterlogging, SF6 gas and leakage current and 3D holographic visualization. The operation shows our solution can effectively sense the environmental object and monitor the substation assets.
Optimal Allocation of Distributed Generation in Micro-Grid Based on the Theory of Life Cycle Cost
Authors: Liu Yong Xiao , Liu Ying , Du Ya Song , Wang Rui Qi , Huang Wei
Published: December 2012

In order to solve the problems of the optimal locations, types and sizes of DG (distributed generation) in an islanded micro-grid, which contains wind turbine, photovoltaic, diesel engine, energy storage device and micro gas turbine. The economic model of optimal allocation was built with the objective function that took LCC (life cycle cost) of DGs and active power loss cost into account. The GA (genetic algorithm) was used to optimize the planning of DG and the optimal scheme was attained. The model comprehensively evaluates the economy of the five kinds of DG in the view of LCC theory, and simultaneously realizes the optimal locations, types and sizes considering the differences of DGs and active power loss of the network. Through the case analysis, the results show this model and method can solve the problem of optimal allocation of DG effectively. It is very practical to guide investing and constructing micro-grid for the investors.
Application of Virtual Visualization in Smart Power Distribution System
Authors: Liu Zhi Gao , Wang Shou Xiang
Published: December 2012

With the increasing development of the power system, particularly, with the proposing of smart grid and the applying of distributed generation technology, the traditional geographic information system (GIS) which relies on the tables, graphs, has become more and more difficult to meet the needs of power system equipment management, and planning. Three-dimensional (3D) GIS has developed to meet the requirement appropriately. In this paper, we choose ArcGIS as the development platform, ESRI CityEngine 2011 and Google SketchUp as the 3D modeling software. By combining the virtual reality(VR) technology and image synthesis technology, a 3D power distribution system is established, which realizes the 3D physical simulation of the transmission lines, electrical equipment, power distribution stations, and distributed generators. This methodology provides a new vision for the modernization of the power distribution system management.
The Stability of Evaporating Thin Liquid Film Containing Insoluble Surfactant on Heated Substrate
Authors: Li Chun Xi , Lu Bing , Ye Xue Min
Published: December 2012

Flow of evaporating thin liquid film containing insoluble surfactant on a uniformally heated substrate is considered in this paper. Coupled nonlinear evolution equations for the film thickness and surfactant concentration are derived on the base of lubrication theory and reasonable boundary conditions. The flow stability of the thin liquid film has been studied using normal mode method according to the linear stability theory. The results show that the film stability is promoted by increasing the Capillary number and the surfactant Peclet number, while increasing the Marangoni number, the interface resistance number, the vapor recoil number and the evaporation number can reduce the stability of the system.
Fire Statistic and Prevention Measures for Cables in Power Plant
Authors: Huang Wei , Zhou Chao , Wang Xin Qun
Published: December 2012

Statistics of cable fire in power plant from 1960’s to 1990’s was carried out at present. Main causes of the fire were analyzed. The external cause accounts for the majority of cable fire. The existed problem in cable fire prevention was summarized; systematic measures from design, construction and operation should be taken into account to reduce the risk of cable fire in power plant.
Selection of Working Fluids for Different Temperature Heat Source Organic Rankine Cycle
Authors: Liu Guang Lin , Xu Jin Liang , Zhang Bing
Published: December 2012

In the current paper, under the condition of different flue gas temperatures and constant flue gas thermal power, the influence of different organic working fluids on the efficiency of sub-critical organic Rankine cycle system were studied. The efficiency and other parameters of the simple system were calculated. The results show that the efficiency of sub-critical organic Rankine cycle system could reach maximum when the parameters of the working fluids in the expander inlet are dry-saturation. Flammability, toxicity, ozone depletion and other factors of the working fluids should be considered in the organic Rankine cycles. R245fa is considered a better choice for low-temperature heat source power generation, and the efficiency of the system is about 10.2%; for the high-temperature heat source, R601a can be considered; however, due to its high flammability, novel working fluids should be further discovered for power generation.
Medium and Long-Term Load Forecast Based on PSO-LS-SVR
Authors: Pan Xue Tao , Qian Feng , Jin Xi
Published: December 2012

Support Vector Regression(SVR) has been successfully applied for medium and long-term load forecasting with many researches．However, the prediction performance relies heavily on the regularity of the set of training samples. Particle swarm optimization (PSO) is used in this paper to refine the weighted coefficient for the Least Square SVM in order to improve the computational efficiency and precision. The comparative analysis with empirical data of a province prove the intended advantages of the proposed method.
Application of Critical Chain Project Scheduling Theory in Power Plant Electrical Equipment Maintenance
Authors: Dong Lei , Zhao Xiao Kun , Zhou Wen Ping , Lv Qin
Published: December 2012

The critical chain project management theory(CCPM) combining the critical chain technology and resource-constrained project scheduling problem (RCPSP) is an important innovation of project control methods, and it’s widely used to optimize the project duration recently. In this paper the theory presented is applied to the maintenance period arrangements of power plant electrical equipment, and a mathematical model of optimizing the maintenance period is established. Then an improved heuristic algorithm is designed and used to establish equipment maintenance precedence network. On this basis, a new identification method of maintenance network based on critical chain is proposed. Finally, it’s verified with a numerical example that the method proposed can effectively shorten the maintenance period of power plant electrical equipment.
Numerical Simulation of Hole Shapes Effect on Film Cooling Effectiveness and Aerodynamics Loss over Flat Plate
Authors: Dong Ruo Ling , Shi Hong Hui , Chen Wei , Zhang Xiao Dong
Published: December 2012

A numerical simulation was conducted to investigate the flow characteristics, film cooling effectiveness and aerodynamics loss over flat plate. Three types of shaped holes, separately, cylindrical hole, laterally diffused hole and converging-expanding hole were studied with 35°inclination angle and 0°compound angle. The inlet diameter of the hole in this paper is 12.7 mm, giving a L/D ratio of 3.5 at a mainstream velocity of 20m/s, turbulence intensity 2%, and temperature ratio to cooling jet 1.97, with blowing ratio M equaling to 0.5. Realizable k-ε turbulence model, standard wall function and SIMPLE method for pressure-velocity coupling were used .The coefficients η and ξ were calculated to analyze cooling effectiveness and aerodynamics loss. Both high film cooling effectiveness and low loss are found with laterally diffused hole. While optimizing the hole geometry in film cooling, cooling effectiveness and aerodynamics loss should been considered simultaneously.
Quantitative Characterization of 2-D Porous Channels by Using Fractal Random Walk Method
Authors: Li Xiao Chuan , Huang Xiang Yong , Cui Xiao Feng
Published: December 2012

An improved random walk mode is proposed based on fractal geometry and random walk theory to characterize the features of porous channels quantitatively. Three different types of fractal Sierpinski carpet structures are obtained by iterative method. The effective thermal conductivities and fractal dimensions are calculated by finite volume method and statistical fractal algorithm respectively. The influences of porosity and pore distribution on effective thermal conductivity are investigated. Results indicate that, the effective thermal conductivity may be different for various structures with the same porosity, and the direction of porous channels formed by connected pores is the critical factor. The spectral fractal dimension of porous channels dD in the direction of temperature gradient coincides with the effective thermal conductivity of Sierpinski carpet.
Simulation Study on the Radiant Tube Installation Height for the Gas-Infrared Heated System
Authors: Zhang Da Ying , Zhuang Wei Dong , Gong Ke Qin
Published: December 2012

The numerical simulation for radiant tube heat transferring process of the gas-infrared heated room was finished. By means of numerical calculation, the influences of radiant tube installation height to the indoor temperature and workspace air temperature as well as the heat radiation flux were studied. The results show: The greater of radiant tube surface installation height, The lower of the workspace average temperature, average radiation temperature and radiant tube total heat flux.
Investigation of Lignite Combustion Characteristics with Thermal Analysis
Authors: Liu Ming Qiang , Liu Jian Zhong , Yu Yu Jie , Wang Zhi Hua , Zhou Jun Hu , Cen Ke Fa
Published: December 2012

Combustion characteristics of three types of lignite (coming from Indonesia, Ximeng, Hami), and a bituminous coal from Shenfu were studied by thermogravimetric analysis (TGA). Combustion parameters including characteristic temperatures, maximum rate of combustion, combustion performance index and activation energy of samples were analyzed. Kinetic parameters of samples were calculated using Jander model. The results showed that the characteristic temperatures of lignite samples are lower than that of bituminous coal. Indonesian lignite has the best combustion performance and the lowest activation energy. It indicates that high quality lignite such as Indonesian lignite has good combustion performance, even better than some bituminous coal, which makes it possible to use lignite by bulk combustion.
Particle Motion in the Vicinity of the Wall of Circulating Fluidized Beds
Authors: Liu Jian Hui , Fan Shuan Shi , Xie Dong Lai
Published: December 2012

High-density circulating fluidized beds (CFB) differ in several respects from low-density CFB systems. In high-density CFB risers, solids move upward throughout the entire riser cross-section, and the net downflow of particles at the wall, a commonly observed feature of fast fluidized beds, is absent. Hence there exists a transition regime from the low density to high density CFB where the net particle motion in the vicinity of the wall is changing from downwards to upwards. This was confirmed by experiments carried in a dual-loop high-density CFB facility with concentric-tube heat exchanger installed in the riser. Local suspension-to-wall heat transfer coefficient and suspension temperature distribution below and above the heat exchange section were measured. Experimental results elucidated that particles move both upwards and downwards in the vicinity of the wall for the operation conditions studied. This alternation of direction leads to higher heat transfer coefficients at both ends of the heat exchange.
Impact of Carbonate Scaling on the Efficiency of Used Geothermal Water Reinjection from Low-Middle Temperature Geothermal Fluid in Xianyang Porous Geothermal Field, NW China
Authors: Ma Zhi Yuan , Yan Hua , Zhou Xin , Hou Chen
Published: December 2012

In low-middle temperature porous geothermal field, precipitation of carbonate from solution to form carbonate scale is confirmed as the main obstacle to efficient reinjection from the used hot fluids in Xianyang city, NW China. The carbonate deposits cause operational problems and may even clog pipeline and reinjection drillholes. For this reason, it's important to understand how impact of carbonate precipitation on the second-hand geothermal water before reinjection has been operated, which concern sustainable utilization of the geothermal water in Xianyang, the famous porous geothermal field in China. In this paper, firstly, different possible minerals precipitation from used geothermal fluid were discussed, and carbonate scaling was regarded as mineral for chemical clog by using combined with lab and chemical simulation method. Secondly, the key impacts of carbonate scaling on clog in reinjection holes such as temperature, degassing, pH, mixing, mineralization were demonstrated based on coupled simulation both in lab experiment and theoretical method. Lastly, the distribution of carbonate scaling and its degree in study area were calculated. The results show that, as the main mineral for precipitation, carbonate exist in most thermal-water wells of study area with the minor or medium scaling, and the carbonate scaling vary increasingly from bottom to top in a single reinjection drillhole, north to south in the study area. According to mineral-dissolution-precipitation equilibrium calculation carbonate saturated tend growth with the temperature and pH increases in study area. The influence of mineralization on carbonate clog is different, common-ion effect in the south of study area is given priority, but in the north salt effect is showed main effect. The analysis for impacts on carbonate clog reflect that carbonate deposit effect are very complicated, which interact each other.
Precipitation Characteristics of Crystallization Fouling on Metal Surface from 0.5mmol/l CaCO3 Solution at 35°C
Authors: Zhou Zhi Gang , Zhang Hua
Published: December 2012

The comparative experiments on CaCO3 crystallization fouling on brass, copper and stainless steel 304 and 316 at different pH at 35°C were carried out. The growing curves of fouling were got by direct weighing after static reaction experiments, and the morphology of crystals at different conditions was obtained by scanning electron microscope (SEM) and the parameters such as polymorphism, crystal size and so on were got, so the growing characteristics of CaCO3 crystallization fouling were known. The experimental results show the mass of crystallization fouling on stainless steeSubscript textl surfaces are almost equal and increasing a little when pH increased, but the mass of fouling on brass and copper surfaces are close and far less than on stainless steel and increasing a lot when pH increased; not only the homogeneous nucleation rate in bulk solution and heterogeneous nucleation rate on metal surface are increased to generate more new crystal nuclear but also square aragonite and calcite are formed more by higher pH, so the mass of metal surfaces is more and the phenomenon is more obvious that single crystal has a size extremum by higher pH.
Simulation of Scavenging Process in a Two-Stroke Gasoline Engine
Authors: Li Chang Yuan , Tang Dong , Li Nan
Published: December 2012

Three-dimension transient numerical simulation of flow field in the transfer ports , exhaust port, intake port, crankcase and cylinder system of two-stroke gasoline engine was studied by using CFD software Fire, and the situations of airflow movement and exhaust gas distribution were presented dynamically in the scavenging process. The results show that flow field structure of the upper cylinder is mainly comprised of a pair of toroidal vortex and tumble vortex, while flow field structure of the lower cylinder is mainly comprised of four radial swirls and "short-circuiting" fuel losses. Along with the progress of scavenging process, the area of fresh charge and mixture increase while the exhaust gas area decreases accordingly. When the piston reaches to the BDC (bottom dead center), the exhaust gas area almost disappears.
Research on Signal Simulator at Crankshaft of Motorcycle Gasoline Engine
Authors: Wang Chang Sheng , Yang Tie Zao , Zhang Haijun , Zhao Hong Jie
Published: December 2012

Cam signals, crankshaft signals and angle signals were simulated by analogue crankshaft position sensors developed by C8051F series micro processors to emulate the operational environment of motorcycle engine. In the software development platform of gasoline engine, software running status of control system was tested. MP424 high-speed sampling card was applied to actually observe properties of ignition advance angle and fuel injection advance angle. The experiment suggested that practically observed fuel injection pulse width, ignition pulse width, properties of ignition advance angle and fuel injection advance angle were the same as those of models of control system software. This proved that the analogue crankshaft position sensor that has been developed is practical and feasible.
Preliminary Research for Optimization of Gas-Steam Combined Cycle Cold-End
Authors: Lu Xiao Feng , Chen Xiu Wen
Published: December 2012

Aiming at the problem of gas-steam combined cycle cold-end system, the system of the circulating water and condenser are considered as a whole. Based on the basic thermodynamics principles, and considering the coupling characteristics of the output load with gas turbine and steam turbine, providing an analytical method that is used to determine the optimal value of condenser vacuum pressure and circulation water flow rate, the optimum operation mode is obtained with the systematic view. And take a 9F-class circulation unit as an example, the operating mode has been verified by adopting this method. The results indicate that the economy of unit increased after optimization.