Search

The huge importance of sustainable energy makes the research of the green and environmental hydrogen energy active in the world. Energy conversion and storage technologies （such as fuel cells or water electrolysis） are capable of readily promoting the interconversion between hydrogen and electric power， for which the development of efficient and stable electrocatalysts is prerequisite. Ordered intermetallic compounds are considered as superior electrocatalysts for energy conversion storage technologies and ideal models for studying the relationship between catalytic activity and structure due to uniform distribution of active sites on surface， welldefined stoichiometry and the better control of the local geometry and electronic structure of metal atoms， compared to disordered alloys as their counterparts. In this review， the challenges of catalysts with regard to hydrogenelectric conversion and the advantages of intermetallic compounds in electrocatalysis are firstly introduced. Secondly， research progress on intermetallic compounds electrocatalysts applied in the interconversion between hydrogen and electric power is mainly discussed from the perspective of activity and stability. Finally， the future development prospects of intermetallic electrocatalysts are summarized and prospected. [ABSTRACT FROM AUTHOR]

Sustainable development of energy and electric power is the primary task to support China’s high-quality economic and social development. Therefore, talent cultivation in the electric power industry is indispensable. Under the background of emerging engineering education, North China Electric Power University, as the cradle of the cultivation of outstanding talents in the electric power industry, took the lead in proposing and constructing the cultivation mode of compound applied chemistry talents based on the concept of “green power”, and successfully applied it to the reform and practice of undergraduate teaching. The practice enables students not only to master the application background and engineering practical skills of electric power environmental protection technology, but also to have the innovative ability of collaborative analysis and solving complex multi-pollutant control problems. The cultivation of high-quality applied chemistry talents in the new era would serve the development of the country. [ABSTRACT FROM AUTHOR]

ntroducing the latest research progress of nanotechnology in photovoltaic power generation, artificial photosynthesis, hydrogen storage, electric power storage, lighting, thermal power and other fields in detail, and analyzes the technical bottlenecks and industry barriers existing in the process of its application.At the same time, it points out the key research directions of nanotechnology in the new energy field in the future, in order to provide reference for further research.Finally, the development prospect of this technology in the new energy industry is prospected. [ABSTRACT FROM AUTHOR]

The secondary energy on board has been gradually replaced by electrical power in more electric aircraft, effectively improving the fuel economy, reliability and maintainability of the aircraft, and has become an important direction of the aviation technology. As the core of the secondary energy system on board, the power system plays a key supporting role in the development of more electric aircraft. The innovative development of the power system and related technologies are the necessary basis to realize the improvement and global optimization of the aircraft comprehensive performance. Based on the concepts and characteristics of more electric aircraft, this paper analyzes and compares the electric power system architecture of three typical more electric aircraft, summarizes the key technologies supporting the development of more electric aircraft electric power system, and discusses the development trend of high voltage, direct current and intelligent more electric aircraft electric power system in the future. [ABSTRACT FROM AUTHOR]

This paper searches and combs the achievements of grey system theory in the past nearly 40 years based on databases of China national knowledge internet (CNKI) and ISI Web of Science. More than 227 thousands literatures were found by inputting 10 phrases such as grey system‑grey number and sequence operator etc. in CNKI. After entering the 21st century, the number of grey system papers included in CNKI database is increasing rapidly. Since 2008, more than 10 thousands papers have been included per year, and more than 15 thousands papers have been included per year since 2014. The grey system method and model are widely used in natural science fields such as physics, chemistry, and biology, as well as engineering technology fields such as transportation, electric power and machinery, and a large number of valuable results have been achieved. From the large number of documents applying the grey system method and model, which are published by the project team undertaking important national science and technology plans and the double first‑class universities in China, it can be seen that the grey system theory plays an important role in promoting China’s scientific and technological progress, innovation and development, and high-level talent training. [ABSTRACT FROM AUTHOR]

Proportional-integral-derivative (PID) control algorithm is widely used in the angle control system of tea garden tractor, but the PID controller brings a lot of parameters setting and hysteresis, which can inevitably reduce the control accuracy and control efficiency. To solve the problem, a tea garden tractor angle controller based on the grey wolf optimization algorithm (GWOA) was proposed. A simplified mathematical model for electric power steering (EPS) system of tea garden tractor was established, and a PID-based motor current-steering wheel angle double closed-loop control strategy was adopted. The GWOA was designed to optimize the parameters of the traditional PID controller, and the PID angle controller based on GWOA was constructed. CARSIM and MATLAB were used to simulate the tractor operation in real time, and the proposed tea garden tractor angle controller algorithm based on GWOA was verified. The results show that the total current harmonic distortion (THD) of the traditional PID controller is 11.46%, and the THD of the particle swarm optimization (PSO) PID controller is 8.12%. The THD of the proposed GWOA-PID controller is 6.28%, which reduces the current harmonics by 45.2%. [ABSTRACT FROM AUTHOR]

Research on the supply and demand of ecosystem services is related to human well-being. The sustainability of the supply of ecosystem services is also the basis for sustainable social, economic and natural environments. Research on supply and demand can provide theoretical guidance for the rational utilization and allocation of natural resources,which helps to improve the ecological compensation mechanism and coordinate the relationship between various stakeholders. We analyze the degree of correspondence between socioeconomic system demand and natural ecosystem supply by analyzing the research results of supply and demand of ecosystem services. It also strengthens our understanding of different factors influencing ecosystem services, which has important reference value for current land spatial planning systems. We systematically summarize the research status of ecosystem services in China and abroad through literature reviews. The literature publication status of supply and demand examines the conceptual connotation of ecosystem service supply and demand, and it distinguishes between the primary connotation and relationship of potential supply, actual supply, potential demand and actual demand. We summarize and compare the research methods related to the supply and demand of ecosystem services, summarizes the practical applications of evaluating the supply and demand of ecosystem services in China and abroad, as well as the problems and limitations in the current research on the supply and demand of ecosystem services. Further, it outlines the scope for future research to provide a reference for the research and application of supply and demand of ecosystem services. [ABSTRACT FROM AUTHOR]

Aiming at the recovery and utilization of train electric braking feedback energy, this paper analyzes the train operation characteristics, and focuses on the relationship between the train operation process and the voltage fluctuation of the traction network. Combined with the dynamic mismatch between the power supply of the traction substation and the electric power of the train, the scheme of the on-board braking energy recovery and utilization system is adopted, and a supercapacitor charging and discharging control strategy based on the dynamic change of the electric power of the train is proposed. The scheme is mainly composed of super capacitor series-parallel energy storage unit and bidirectional DC-DC converter. In this paper, MATLAB is used for modeling and simulation analysis. The simulation results show that the control strategy can effectively recover and utilize the train braking energy while suppressing the voltage fluctuation of the traction network, which provides an effective solution for the recovery and utilization of the train braking energy. [ABSTRACT FROM AUTHOR]

The parking environment for drivers is now increasingly complex, and parking has become a driving phenomenon with high incidence of accidents. To solve the problem, a method of path planning for autonomous parking was proposed based on improved β-spline theory. The vehicle kinematical model was established, and considering the vehicle kinematics and electric power steering(EPS) performance requirements in parking environment, the path collision avoidance constraints and the vehicle steering wheel angle and angular velocity constraints were established. The simulation model was built by Matlab/Simulink. According to the actual parking scenario, three autonomous parallel parking conditions were designed, and the path planning was simulated. The results show that the proposed algorithm can realize autonomous parking for different sizes of parking lot, and the planned path curvature is continuous with slowly changed curvature. The vehicle kinematics and EPS performance requirements can be met with high parking efficiency. [ABSTRACT FROM AUTHOR]

Plasma-activated water (PAW) has been proven to have broad-spectrum bactericidal properties, and can effectively kill microorganisms on fresh foods and inhibit their spoilage. Low-temperature PAW sterilization is viewed as an emerging cold sterilization technology, presenting great potential for the application in food production and safety control, which has attracted wide attention from scholars at home and abroad. However, there are few research reports on PAW generating equipment, and its design basis is still lacking. In order to improve the level of PAW equipment development and application, the equipment for producing low-temperature PAW was developed in this study based on the basic principle of plasma generation by dielectric barrier discharge. The system of this equipment included dielectric barrier discharge components, ventilation channels of heat dissipation, flow channels of activated water, the high voltage alternating current power supply, and so on. The dielectric barrier discharge components were composed of a cylindrical high-voltage discharge electrode and a flat-shaped low-voltage discharge electrode in an upper-down parallel configuration with the uniform gas gap, in which the stainless-steel plate for water flow and the flowing water film was integrated to be used as the low-voltage electrode, realizing uniform plasma generation and continuous and stable production of activated water. The heat dissipation of the high-voltage discharge electrode employed two bidirectional-countercurrent ventilation channels inside and outside the electrode tube, which effectively improved the heat dissipation effect and working stability of the equipment. A structure of alternating current-direct current-alternating current was designed as the power circuit of the high-voltage alternating current power supply to realize the energy supply of dielectric barrier discharge. And the control circuit could be realized the monitoring and adjustment of parameters such as frequency, voltage, and current, etc. To meet the diversified requirements for the application of plasma-activated water, some structural parameters and working parameters of this equipment were designed to be continuously adjustable within a certain range, which included the inclination angle of guide plate, the air gap between the high-voltage discharge electrode and the guide plate, water flow rate, supply power, working voltage, working current, and so on. To verify the effect of plasma-activated water treatment from this equipment on the vegetables, the fresh-cut potato slices were simulated to be infected with Escherichia coli, and sterilization cleaning and preservation by using the plasma-activated water was performed. The conditions for the sterilizing of plasma-activated water on Escherichia coli in the potato slices were optimized to result in the optimal sterilization rate (98.65±0.59) %, in which the water flow was 600 mL/min, the air gap was 10 mm, the mass ratio of material to activated water was 1∶20, the power supply voltage was 137.4 V, and the sterilization time was 4.72 min. Compared with the treatment without cleaning and the treatment with distilled water cleaning, the treatment of cleaning with the plasma-activated water by using the above-optimized conditions contributed to relatively higher hardness, lower color difference, lower relative conductivity, lower soluble solid content, and lower decay rate in the bacteria-contaminated potato slices during storage. After 24 d of storage, the bacteria-infected potato slices without cleaning, with distilled water cleaning, and with PAW cleaning achieved a hardness of (3.01±0.84), (3.54±0.81), (4.70±0.48) N, respectively, a color difference of 22.08±1.05, 13.21±1.43, 7.35±0.81, respectively, a relative conductivity of (28.00±6.43) %, (26.72±2.07) %, (17.19±2.26) %, respectively, a soluble solid content of (6.850±0.120) %, (5.430±0.006) %, (3.080±0.006) %, respectively, and a decay rate of (87.04±1.63) %, (76.32±1.60) %, (52.09±1.41) %, respectively, showing good advantages of sterilization and preservation. This study could provide a reference for the development and the industrial application of the sterilization technology of plasma-activated water [ABSTRACT FROM AUTHOR]

In the traditional centralized data trading system, sensitive data such as electric power data are easily abused due to duplicability. To address this, the blockchain-based power data's capitalization and trading system was proposed. Considering the trust in blockchain technology, a multi-party trusty network can be established between multiple parties in distributed ledger with cryptographic algorithms, multi-centralized architecture and distributed multi-party consensus protocol. The system was developed with Hyperledger's consortium blockchain framework Fabric, which made power data trading safe, transparent, traceable and immutable by means of the technical characteristics of the blockchain. In addition, a supervision mechanism was introduced. The system also provided Web service as application layer for ease of use. Finally, the system was tested by simulating multi-node deployment on a single device. And the results show that the system runs well in integrated test, meets the design requirements, and has low maintenance costs and enhances security. Compared with the traditional data trading system, the blockchain-based power data's capitalization and trading system demonstrates comprehensive functionality and security advantages. [ABSTRACT FROM AUTHOR]

Aiming at the problem of low accuracy of traditional prediction methods of anti-electricity stealing, a prediction method of anti-electricity stealing based on big data of electric power was proposed. This method firstly constructed samples of electricity stealing data according to abnormal rules, and introduced the growth rate of line loss rate constraint conditions. Then it used four machine learning classification algorithms to build a prediction model on the voltage, current and power factor data sets respectively, combined the users with abnormal data output and users with abnormal line loss to output a list of users suspected of stealing electricity. Experimental results showed that the prediction accuracy of the method was satisfactory, and it was efficient and feasible in identifying users suspected of stealing electricity. [ABSTRACT FROM AUTHOR]

In order to solve the problem that the working state of the pure electric bus power battery is susceptible to many factors, the fuzzy logic algorithm is UBed to evaluate the working status of the pure electric bus power battery. According to the diversity and ambiguity of the working state changing of the power battery, the total voltage, temperature and the insulation resistance of power battery are selected as the evaluation parameters, the corresponding membership function and fuzzy evaluation matrix are established, and the fuzzy mathematics evaluation model is established. The working state of the power battery obtained by the evaluation model is compared with the actual working state of the research object, and the results show that the obtained results are consistent with the actual situation. It can be seen that the constructed evaluation model can realize the fault prediction of the pure electric bus battery, thereby improving the safety of the pure electric bus operation and ensuring the normal operation of the bus operation system. [ABSTRACT FROM AUTHOR]

Greenhouses in remote areas have difficulty to access power. This paper aims to resolve this problem with a new system that can supply electricity to low-power devices such as energy-saving lamps, temperature and humidity monitoring system, digital equipment and other electrical equipment in greenhouses in remote areas. Current power supply to greenhouses uses distributed energy sources from wind and solar, which are not portable and susceptible to environmental changes. Under certain circumstances, power supplied from these systems is insufficient or even fails. As such, there is an increase in developing portable power generation systems. For example, in China, portable multi-purpose photovoltaic power generation system had been developed for agricultural production using remote-control system (programmable logic controller, PLC) to monitor pumping stations. There was also portable multi-power source power generation system to compliment wind power, solar energy and hand-cranked energy generation. Devices to generate power using the difference in temperature between human body and ambient environment exist, which are powerful enough to power LED lights. Another portable device is to generate thermal energy by burning combustibles in the field. All these portable devices have their pros and cons and the purpose of this paper is to present a new portable thermoelectric power generation system. The size of the system was 20 cm × 20 cm × 5 cm weighted 2580 grams, and its energy sources was from combusting biomass. A flat heat pipe was used for thermal conduction. We simulated performance of the system using the ANSYS, and set an experimental platform to test it. The experimental data showed that the highest temperature at the hot end of the system was 270.1 ℃, the maximum power output was 10.7 W, and the electrical efficiency was 5.73%. The results also revealed that the system had advantages of high hot-end temperature and high thermoelectric efficiency. It can generate electricity under extreme conditions in remote areas. Numerical and experimental analysis of various inputs and outputs indicated that the system is portable, the hot end temperature is high, and the thermoelectric efficiency is high. It provides a baseline for study of portable power generation system. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the rationality of clinical use of Danhong injection from the perspective of contraindica - tions, and provide reference for the evaluation of similar traditional Chinese medicines for promoting blood circulation and relieving blood stasis. Methods: Ret respective matching method was used in the study. Two hundred cases treated with Danhong injection and 120 cases not treated with Danhong injection from March, 2017 to April, 2018 in Beijing Electric Power Hospital of State Grid were randomly selected for the study. The bleeding risks and grades of patients with ischemic stroke and coronary heart diseases were evaluated using S2 TOP - BLEED scores and CRUSADE scores, respectively. Then, an investigation was also made on the hemorrhage of the bleeding patients with various grades. Results: In the 200 patients treated with Danhong injection, 13 developed hemorrhage, of whom 7 were evaluated as high risk patients by S2 TOP - BLEED scores, and 6 were evaluated as high risk patients by CRUSADE scores, with the rate of hemorrhage, accounting for 6. 5% (13/200). Of the 120 patients without treatment of Danhong injection, only 1 patient had hemorrhage evaluated as extremely high risk patients by CRUSADE scores, 1 with the rate of hemorrhage accounting for 0. 8 % (1/120). Those patients evaluated as extremely high risk ones were all treated with at least one kind of anticoagulant or antiplatelet drugs. Cbnclusiotl: For the ischemic stroke patients evaluated as high risk ones by S2TOP-BLEED scores and those coronary heart disease patients evaluated as extremely high risk patients and treated with anticoagulant or antiplatelet drugs, the use of Danhong injection should be avoided if signs of hemorrhage develop. [ABSTRACT FROM AUTHOR]

This paper introduces the design and implementation process of electric power safety experiment training system based on 3D virtual simulation technology, and expounds the whole process of power safety experiment training system from system requirement and function design to system design and system realization. The system is realized by using ASP. NET technology and unity3D technology effectively. Management, student management, test question management, task management, peformance management, power safety data management and other core functions can be completed by the system. The examination system makes use of unity3D technology which applies 3D scene and WEB design theory. The electric power workers can simulate and manipulate the whole maintenance process through computer so as to improve the employees of electric power construction operation skills. [ABSTRACT FROM AUTHOR]

Silo is widely used in grain, logistics, electric power, metallurgy and other industries. Therefore, the reasonable design of silo structure is the key. China is a large country of grain production, with application of the modern granary environmental protection, energy saving, green and other concepts, the cylinder wall is higher, and larger diameter, occupies less land, saves resources of the silo and is more and more in line with the future development trend of granary, and with the trend of rapid development around the world. With the increasing height and diameter of silo, the problem of failure in silo discharging is becoming more prominent. The dynamic lateral pressure of grain silo during discharging is the major cause of silo failure. In this paper, based on the indoor grain silo discharging model test, the whole process of the silo center emptying was recorded with high-speed camera, the flow pattern of grain was analyzed with image processing technology, and the dynamic pressure generated during the discharge process was measured. Based on this test, the particle flow code (PFC3D) was used to carry out numerical simulation to track the movement of specific particles in the test. By comparing the results of the experiment and the numerical simulation, the mechanism of overpressure in the discharge of the silo was explored. Through this study, in the process of discharging in the center, there were two kinds of flow states, the mass flow and the tubular flow. At the beginning of the discharge, the stored material flowed as mass flow. After a period of time, the upper part of the material flowed as mass flow, the bottom of the storage was a tubular flow, and the mass flow was in the high diameter ratio close to 1 of the height position to convert to tubular flow. When the discharging height reached 1.1m, the stored material flowed in tubular flow until the discharge was completed. Both the dynamic lateral pressure and the static lateral pressure increased with the depth of the measuring point, and the dynamic lateral pressure was greater than the static lateral pressure. At the beginning of the discharge, the dynamic lateral pressure measured by the silo suddenly increased, and then the dynamic lateral pressure value decreased with the continuous reduction of the storage height. The overpressure coefficient measured by the three groups of sensors was larger in the height range of the high diameter ratio close to 1, and the overpressure phenomenon was obvious. In the process of silo discharging, the speed of tubular flow of the bottom stored material was greater than the speed of the mass flow of the middle and upper stored material. There was a pressure arch at the junction of the two flow states, and the existence of the pressurized arch hindered the normal flow of the upper stored material, which led to the self-weight of the stored material and the additional force caused by the change of momentum was almost entirely by the arch, resulting in the increase of the dynamic lateral pressure and a significant overpressure phenomenon. [ABSTRACT FROM AUTHOR]

Pure electric vehicles are the hotspot of current research and development, and the power train parameter matching design is the key technology of pure electric vehicles. In this paper, a power train parameter matching design is applied to a pure electric vehicle. According to the performance requirements of the vehicle and the dynamic principle, the design and matching calculation of the vehicle’s motor, battery, main reduction ratio and other dynamic parameters are carried out. The AVL CRUISE software is used to establish the vehicle model of the target vehicle, and the braking energy recovery model is built with Simulink. Combined with two typical working conditions, NEDC and FTP75, the joint simulation is carried out. The simulation results show that the power train parameters and braking energy recovery control strategy designed in this paper can meet the performance requirements of the target vehicle, which can effectively improve the dynamic performance of the vehicle, increase the driving range of the vehicle and improve the battery life. The research content of this paper can provide reference for the research of design and control strategy of pure electric vehicle power train. [ABSTRACT FROM AUTHOR]

To solve the problems of traditional vehicle EPS system performance test with long test period, high input cost and low efficiency, the experimental platform was redeveloped based on the TAT-6/TL type of electric power steering in the loop simulation test bench. According to the working characteristics and testing requirements of EPS system, the electric push rod loading device was selected, and the electric putter real-time control was realized based on the speed and steering wheel angle by MCS912 controller. The steering resistance was accurately simulated under different steering conditions. By the virtual test technology and EPS test bench, the debugging was conveniently and quickly realized to reduce the dependence on real vehicle test. The performance of the linear EPS system was verified by the resistance test of ground and steering condition, the current follower and the response characteristic test. The results show that the simulation and test results are basically consistent, which can meet the requirements of EPS performance test. [ABSTRACT FROM AUTHOR]

The unit energy consumption of vaporization-transportation is not only an important operation indicator, but also the basis of energy-saving study at LNG terminal. This paper addressed the issue in the following process： Firstly, the process and equipment involved was introduced; subsequently, the electric power of low-pressure pump, high-pressure pump, seawater pump and other power consumption equipments were calculated, as well as the gas-consumption of torch eve-burning lamps and SCV. After that, the unit energy consumption was obtained as 4. 625 kgce/t if 1 t natural gas was vaporized and transported in the minimum transportation conditions with ORV as vaporizer in summer, and the value shifted to be 25. 83 kgce/t in the maximum transportation conditions with SCV as vaporizer in winter. It was found in the comparison that the unit energy consumption of running SCV was much higher than the running ORV. Finally, the relationship between the natural gas flow of transportation and the unit energy consumption was determined by computer program, as showing in the curve. From the curve, it was found that the minimum unit energy consumption about vaporization-transportation was 1. 946 kgce/t，while the corresponding natural gas flow of transportation was 690 t/h. Besides, the unit energy consumption decreased while natural gas flow of transportation increased， but the unit energy consumption would tncrease rapidly reversely at the moment of adding running equipments. [ABSTRACT FROM AUTHOR]

A method of using auxiliary electric current to restrain the stray corrosion of EDM of titanium alloy machined in water is proposed. In the method, an auxiliary power supply is used to provide enough cathode current to make the metal interface electronegative, as a result of which, the stray corrosion is inhibited. The mechanism of stray corrosion and how to restrain it by auxiliary electric current are studied. The surfaces of titanium alloy machined before and after adopting auxiliary electric current are tested by several means, such as electric field simulation analysis, electrical discharge machining tests, surface morphology and component analysis, and so on. The experimental results show that the auxiliary electric current can efficiently eliminate the stray corrosion of EDM of titanium alloy machined in water. [ABSTRACT FROM AUTHOR]

According to dipole model, the electromagnetic filed distribution laws at the discharge instantly time are acquired. A calculation model and a numerical solution of electric and magnetic fields of indirect lightning over-voltage are proprosed. The influence laws of lightning current amplitude, cable length, cable height, termination resistor and lightning location on induced over-voltage are discovered: peak value of indirect lightning over-voltage is proportional to lightning current amplitude, cable length and cable height. But when the cable length is increased to a certain size, the peak value of indirect lightning overvoltage increase rate tends to be small; when the starting end is the match resistance, the indirect lightning over-voltage of ending increases with the increase of end resistance. The lightning location in the vertical direction of the cable on distance increasing, the indirect lightning over-voltage rapidly decreases, and does not become direct ratio with the distance, which provides the quantitative indicators to the lightning protection design of the military power supply. [ABSTRACT FROM AUTHOR]

Oxy-fuel combustion is an effective and advanced technology of mitigating CO2emission in thermal power plants. Due to the addition of air separation unit (ASU) and CO2 compression and purification unit (CPU), the thermal system is more complex and has a large optimization potential. Aspen Plus was used to simulate and analyze the oxy-fuel combustion system including ASU, CPU and thermal power system. The results indicate that the optimal oxygen concentration is 96% and the power consumption of ASU can decrease by 5.52%. When a 1000 MW supercritical unit was retrofitted to an oxy-fuel plant,the proportion of power consumption by ASU and CPU to the total power output is 13.39% and 8.62% respectively. In addition, the net efficiency is reduced to 30.99% from 42.43%. It reduces the steam turbine swept volume by recovering the waste heat of ASU and CPU, which can increase 4.33% of the net efficiency. [ABSTRACT FROM AUTHOR]

Optimization of wind turbines positioning on large complex wind farm has been investigated in the present study with the objectives of maximum extracted wind power and minimum wind farm operating cost. A symmetrical regular hill is selected as the research model. The widely used engineering models are used to investigate the flow field and then to predict the annual power production of the wind farm. Commercial software Fluent is also employed to verify the accuracy of these engineering models. A cost model is designed based on engineering experience to predict the operating cost. Then, NSGA-II multi-objective optimization algorithm is applied with the number and position of wind turbines, and compared with the single-objective optimization. Finally, individuals with better performance are evaluated with respect to various criteria, and associated configurations and characteristic parameters of wind farm are presented. The simulation shows that these algorithms can be used for micro-sitting within a real wind farm in the future. [ABSTRACT FROM AUTHOR]

For assessing the component deterioration effects on a high bypass ratio turbofan engine, the component characteristic correction model associated with flight cycles is established based on the analysis of compressor and turbine components deterioration factors. Combined with component matching method, the simulation model analyzing component deterioration effect on a high bypass ratio turbofan engine is established, and Newton-Raphson method is adopted to solve the nonlinear equations. Taking a high bypass ratio turbofan engine for example, component deterioration effect on engine performance parameters such as engine thrust and special fuel consumption are quantitatively analyzed under 8 typical operation conditions. Results show that when the engine reaches the renovates sate, component deterioration lowers the thrust by 7. 29%, increases the special fuel consumption by 8. 23%, increases the engine gas temperature by 68. 3 K, and reduces the surge margin significantly. [ABSTRACT FROM AUTHOR]

The dynamic inflow model in yaw condition was constructed based on the theory of BEM revised model and Pitt-Peter model; besides first-order differential equation of dynamic inflow model was also figured out by using fourth-order Runge-Kutta method. When taking large deformation of flexible blade during the working proceed and the feedback of flexible structural deformation on dynamic inflow model into consideration, the gradient mechanisms of induce factor on wind turbine were obtained in different circumstances, such as in the wind shear, wind turbulence, yaw, transition of rotor speed and blade pitch angel. Dynamic induce factor of one 5MW wind turbine was figured out, dynamic description of induce factor was founded, what's more dynamic inflow model and analytical method suitable for flexible blade were established, all these calculate were achieved by employing MATLAB programming. The validity and practicality of dynamic inflow model with flexible structural feedback were confirmed by comparing the calculate results of different models. [ABSTRACT FROM AUTHOR]

With the advantages of low noise, low infrared signature and high dependability, the fuel cells can be used for the military vehicles and field power supply. The reaction characteristics of proton exchange membrane fuel cell ( PEMFC) system are affected by self-configuration, environment and other factors. For the limit of sensor technology, the inner temperature and humidity of the fuel system can't be measured immediately, and its reaction characteristics are different every time. System model is difficult to build, its inner humidity can't be well controlled using a traditional control method. For 3 kW PEMFC system, a simple control system was built to control the humidity dynamically, which keeps the humidity changing up and down alternately in dynamic threshold. The limit of system model is get rid of by this method, avoiding the humidity excursion caused by steadily control. Finally the feasibility of this control method was validated through experiment. [ABSTRACT FROM AUTHOR]

The wave rotor is a self-cooled dynamic pressure exchange machine that can improve the engine performance and fit diversified course. In this paper, the thermo-cycle analysis mode of a wave-rotor-topped small gas turbine engines is established. When the compressor, the turbine pressure ratio, and the turbine inlet temperature vary in the thermodynamic calculation according to the anticipated design objectives in the five considered cases, the influence of wave rotor on the performance of small gas turbine engines is investigated. The variable laws of wave rotor-applied combustor work condition is discussed. The best performance is obtained in the topped engine operates with the same compressor pres- sure ratio, inlet temperature and physical compressor like that of the baseline engine. The prime performance optimized region and the combustor work condition of the wave-rotor-topped small gas turbine engines are obtained. [ABSTRACT FROM AUTHOR]