NOx sensors, as a core component of diesel engine exhaust treatment system, play an important role in exhaust emission control, which can accurately and quickly detect the NOx and O2 concentration. It has become a nec...NOx sensors, as a core component of diesel engine exhaust treatment system, play an important role in exhaust emission control, which can accurately and quickly detect the NOx and O2 concentration. It has become a necessary option for the detection of existing exhaust emission standards. At present, there is limited and scattered information on knowledge and test methods of NOx sensors, the research of NOx sensors has become a challenging research topic at home and abroad. Based on these requirements, the article systematically integrates the knowledge of principle and testing methods. First of all, through introducing functional description of NOx sensors and the basic principle of NOx sensors, the relevant scholars can have an overall understanding of the product and master the operation mode of products. Secondly, the current status of performance test bench and methods of NOx sensors were described, which can contribute to having a clear understanding of the development process. After that, a new structure of NOx sensors test bench was purposed, which contains six major units including standard gas source, gas mixing unit, analyzer measurement unit, sensor measurement unit, data processing and display unit, exhaust gas treatment unit. And the test bench was validated. The experimental results show that the test bench has the advantages of high-repeatability, high reliability and low cost. And it can realize automatic detection of multiple target values, which is worthy further promotion. Thereby, the article can contribute to the development of its technology indirectly.展开更多
A heat transfer performance testing system is presented with its hardware structure, operation principle, and software control and measurement system. Working fluids of the subsystem include thermal conducting oil, co...A heat transfer performance testing system is presented with its hardware structure, operation principle, and software control and measurement system. Working fluids of the subsystem include thermal conducting oil, compressed air, glycol water solution and water as the heating fluids, and air and water as the cooling fluids. The heat transfer performance testing of heat exchangers can be conducted not only for a conventional one heating fluid to one cooling fluid, but also for a compound air cooling heat exchanger with two or three heating fluids in parallel or in series. The control and measurement system is implemented based on a LabVIEW software platform, consisting of the data acquisition and process system, and the automotive operation and control system. By using advanced measuring instruments combined with sound computer software control, the testing system has characteristics of a compact structure, high accuracy, a wide range of testing scope and a friendly operation interface. The uncertainty of the total heat transfer coefficient K is less than 5%. The testing system provides a reliable performance testing platform for designing and developing new heat exchangers.展开更多
In view of the limitations of solid metal heat sink in the heat dissipation of high power light emitting diode （LED）, a kind of miniaturized phase change heat sink is developed for high power LED packaging. First, t...In view of the limitations of solid metal heat sink in the heat dissipation of high power light emitting diode （LED）, a kind of miniaturized phase change heat sink is developed for high power LED packaging. First, the fabrication process of miniaturized phase change heat sink is investigated, upon which all parts of the heat sink are fabricated including main-body and end-cover of the heat sink, the formation of three-dimensional boiling structures at the evaporation end, the sintering of the wick, and the encapsulation of high power LED phase change heat sink. Subsequently, with the assistance of the developed testing system, heat transfer performance of the heat sink is tested under the condition of natural convection, upon which the influence of thermal load and working medium on the heat transfer performance is investigated. Finally, the heat transfer performance of the developed miniaturized phase change heat sink is compared with that of metal solid heat sink. Results show that the developed miniaturized phase change heat sink presents much better heat transfer performance over traditional metal solid heat sink, and is suitable for the packaging of high power LED.展开更多
To realize automatic control of automobile transmission performance test stand Methods The automatic control technique of the lubricant temperature,the program- controll- edautomaticshifting of the transmission,the c...To realize automatic control of automobile transmission performance test stand Methods The automatic control technique of the lubricant temperature,the program- controll- edautomaticshifting of the transmission,the continuous adjusting of revolution speed and load, data-acquisition and data real-time processing were adopted.Results The lubricant temperature was controlled at the set temperature ±2℃.The automatic shifting of the trans- mission is simple,reliable and accurate.The automatic adjusting of load and rotation speed is rapidandaccurate,the torque divergence is ±1N·m,the rotation speed divergence is ±5r/min Conclusion The four kinds of techniques are applied into the automobile transmission perfor- mance test stand successfully. mancetest stand successfully.展开更多
he thermal performance test of the horizontal coaxial double tube hot gas duct (HGD) with an internal thermal insulation for the 10MW High Temperature Reactor Test Module (HTR10) was conducted on a Helium Test Loop(HE...he thermal performance test of the horizontal coaxial double tube hot gas duct (HGD) with an internal thermal insulation for the 10MW High Temperature Reactor Test Module (HTR10) was conducted on a Helium Test Loop(HETL). The present paper deals with the technical feature of the HETL, the test section and the thermal performance test of the HGD. The HGD test section with a triple tube structure includes an inner heater, a HGD model and a coldhot gas mixer. A counterflow of cold and hot helium gas under the pressure of about 3.0 MPa and the minimum temperature of 100℃ in the annular passage and the maximum of 950℃ in the central tube of the HGD model was formed. The HGD model was undergone 20 times of pressure cycle test under the pressure ranging from 0.1 to 3.4 MPa, 18 times of the temperature cycle test under the temperature ranging from 100 to 950℃ and high temperature (700 to 950℃) helium flow test for a period of more than 350 hours. The effective thermal conductivity (λeff) of the internal insulation of the HGD was investigated experimentally. The relationship of the effective thermal conductivity with the average tmperature of the internal insulation layer is λeff(W/m/℃)=0.3512+0.0003T(℃). The test results indicate that the HGD model has good abilities to resist heat flux from the central tube to the annular passage, temperature variations, and pressure variations.展开更多
To improve the transmission accuracy and stiffness of the ball cycloid reducer, the authors developed a novel cycloid ball reducer, which uses a full complement ball as its gear teeth. Ceramic balls are used to get be...To improve the transmission accuracy and stiffness of the ball cycloid reducer, the authors developed a novel cycloid ball reducer, which uses a full complement ball as its gear teeth. Ceramic balls are used to get better performance in severe working conditions. A simple synthesis method was also found to determine the raceway forms and compute the contact forces among the balls and raceways. The Contact Stress Analysis (CSA) computer program was used to optimize the design of the reducer. In this paper, the following topics are covered: (1) Study of the geometry of the raceways. (2) Analyses of the principal curvature of the raceways are also accomplished. In addition, the modification of the raceway is put forward. (3) The contact forces and the reducer efficiency are evaluated. (4) Study of the performance of ceramic balls used in the CBR. A reducer using the above design technique was tested and the performances show that the reducer has high precision and rigidity. An increase of more than 50 percent transmission power was realized in the new gearing.展开更多
Customizing applications through program configuration options has been proved by many open-source and commercial projects as one of the best practices in software engineering. However, traditional performance testing...Customizing applications through program configuration options has been proved by many open-source and commercial projects as one of the best practices in software engineering. However, traditional performance testing is not in synch with this industrial practice. Traditional performance testing techniques consider program inputs as the only external factor. It ignores the performance influence of configuration options. This study aims to stimulate research interest in performance testing in the context of configurable software systems by answering three research questions. That is, why it is necessary to conduct research in performance testing, what are the state-of-the-art techniques, and how do we conduct performance testing research in configurable software systems. In this study, we examine the unique characteristics and challenges of performance testing research in configurable software systems. We review and discuss research topics on the performance bug study, performance anti-patterns, program analysis, and performance testing. We share the research findings from the empirical study and outline the opening opportunities for new and advanced researchers to contribute to the research community.展开更多
The performance test of Intelligent Network (IN) system is an important phase in developing IN system. We designed a set of simple and practical methods on the basis of the characteristics of IN for the performance te...The performance test of Intelligent Network (IN) system is an important phase in developing IN system. We designed a set of simple and practical methods on the basis of the characteristics of IN for the performance test of the prototype of the BUPT-IN system. The test result is well satisfied and shows that the performance of the BUPT-IN system reaches the original goal.展开更多
Condenser is one of the important auxiliary equipments in nuclear power plants. The thermal efficiency of the entire unit was depended on the condenser performance. Cleanliness factor and condenser corrected pressure ...Condenser is one of the important auxiliary equipments in nuclear power plants. The thermal efficiency of the entire unit was depended on the condenser performance. Cleanliness factor and condenser corrected pressure are the two most important evaluation indexes. The definition and derivation of these two evaluation indexes were elaborated and clarified in this paper. And the condenser performance at variable conditions was analyzed. The seawater temperature, pipe plugging rate and seawater volume rate effect on unit output was calculated. The calculation method was simple, which can provide reference guidance for similar power plant.展开更多
Data consisting of test performance records of 725 bulls was analysed to evaluate trends for growth and feed efficiency, and to determine environmental factors that influence growth of range performance tested bulls i...Data consisting of test performance records of 725 bulls was analysed to evaluate trends for growth and feed efficiency, and to determine environmental factors that influence growth of range performance tested bulls in the arid sweet bushveld of South Africa. Performance data were subjected to regression procedures to estimate parameters of the slope (β) and intercept (α) for average daily gain (ADG) and Kleiber ratio (KR). Mixed procedures were applied to test for sources of variation in ADG and KR. There was an increase of 3.481 g/day/year and 0.528 g/day/ year in ADG for Nguni and Bonsmara bulls, respectively. The ADG trends’ respective feed efficiency as reflected by KR was 0.093 and 0.059. Herd of origin and test-year were the sources of variation for ADG while the variation in KR was due to the herd of origin, test-year, start-age and start-weight. Results indicated a steady increase in ADG and KR for range performance tested bulls in the arid sweet bushveld.展开更多
In a performance test, the standards for assessing its test results are not sufficiently determined due to the lack of a well-structured test developing methods which are found in a functionality test. By extending th...In a performance test, the standards for assessing its test results are not sufficiently determined due to the lack of a well-structured test developing methods which are found in a functionality test. By extending the established workflow structure, this approach will concentrate on tradeoffs within T-workflow and further develop tests based on T-workflow. The monitoring and tuning point have also been investigated to understand the validity and performance of software. Finally through a case study, it has been shown that better assessment of software performance can be obtained with the suggested tests developed based on T-workflow and by locating its monitoring point and tuning point.展开更多
Based on the 1D-blade element momentum theory (BEM) with the improved tip loss correction introduced, a new aerodynamic model of wind turbine is developed. Using one high aerodynamic performance airfoil with 18% relat...Based on the 1D-blade element momentum theory (BEM) with the improved tip loss correction introduced, a new aerodynamic model of wind turbine is developed. Using one high aerodynamic performance airfoil with 18% relative thickness, one small wind turbine blade is designed and the distribution of the chord and twist angle of the blade are determined. According to the shape parameters of the blade, a method to set up the 3D model is presented by investigating the coordinate position of each section of the blade. Based on the fiber reinforced polymer (FRP) molding technology, the manufacturing process of wind turbine blade is put forward. Using fiber reinforced polymer, the wind turbine blades are manufactured by the mold making and layer process. A test platform and method of wind turbine output power are carried out, the output powers at different speeds of the wind turbine are obtained and discussed. The comparison between the designed and one existing wind turbine rotor is completed to show the reliability and superiority of the design and test method presented in this paper.展开更多
Two single-storey single-span reinforcement concrete （RC） frame structures strengthened with Y-eccentrically brace were designed and manufactured to be 1/3 scale. The pseudo-dynamic testing method was used to study ...Two single-storey single-span reinforcement concrete （RC） frame structures strengthened with Y-eccentrically brace were designed and manufactured to be 1/3 scale. The pseudo-dynamic testing method was used to study the mechanical characteristics and the seismic performance under E1-Centro earthquake action with different peak acceleration adjusted by China＇s Code for Seismic Design of Buildings. The test results indicate that RC frame structures strengthened with Y- eccentrically steel brace present perfect seismic performance under strong earthquake action owing to the good ductility, strong bearing capability and fine energy absorbing capability provided by energy dissipation element and high lateral stiffness provided by diagonal braces. The seismic performance is also affected by the length of outsourcing steel at the joint between energy dissipation element of eccentric steel brace and RC frame beam. The joint should be considerably designed to make sure that shear failure can firstly occur in energy dissipation element.展开更多
Most materials can be easily corroded or ineffective in carbonaceous atmospheres at high temperatures in the reactor core of the high temperature gas-cooled reactor(HTGR).To solve the problem,a material performance te...Most materials can be easily corroded or ineffective in carbonaceous atmospheres at high temperatures in the reactor core of the high temperature gas-cooled reactor(HTGR).To solve the problem,a material performance test apparatus was built to provide reliable materials and technical support for relevant experiments of the HTGR.The apparatus uses a center high-purity graphite heater and surrounding thermal insulating layers made of carbon fiber felt to form a strong carbon reducing atmosphere inside the apparatus.Specially designed tungsten rhenium thermocouples which can endure high temperatures in carbonaceous atmospheres are used to control the temperature field.A typical experimental process was analyzed in the paper,which lasted 76 hours including seven stages.Experimental results showed the test apparatus could completely simulate the carbon reduction atmosphere and high temperature environment the same as that confronted in the real reactor and the performance of screened materials had been successfully tested and verified.Test temperature in the apparatus could be elevated up to 1600oC,which covered the whole temperature range of the normal operation and accident condition of HTGR and could fully meet the test requirements of materials used in the reactor.展开更多
文摘NOx sensors, as a core component of diesel engine exhaust treatment system, play an important role in exhaust emission control, which can accurately and quickly detect the NOx and O2 concentration. It has become a necessary option for the detection of existing exhaust emission standards. At present, there is limited and scattered information on knowledge and test methods of NOx sensors, the research of NOx sensors has become a challenging research topic at home and abroad. Based on these requirements, the article systematically integrates the knowledge of principle and testing methods. First of all, through introducing functional description of NOx sensors and the basic principle of NOx sensors, the relevant scholars can have an overall understanding of the product and master the operation mode of products. Secondly, the current status of performance test bench and methods of NOx sensors were described, which can contribute to having a clear understanding of the development process. After that, a new structure of NOx sensors test bench was purposed, which contains six major units including standard gas source, gas mixing unit, analyzer measurement unit, sensor measurement unit, data processing and display unit, exhaust gas treatment unit. And the test bench was validated. The experimental results show that the test bench has the advantages of high-repeatability, high reliability and low cost. And it can realize automatic detection of multiple target values, which is worthy further promotion. Thereby, the article can contribute to the development of its technology indirectly.
基金The National Natural Science Foundation of China(No. 50976022)
文摘A heat transfer performance testing system is presented with its hardware structure, operation principle, and software control and measurement system. Working fluids of the subsystem include thermal conducting oil, compressed air, glycol water solution and water as the heating fluids, and air and water as the cooling fluids. The heat transfer performance testing of heat exchangers can be conducted not only for a conventional one heating fluid to one cooling fluid, but also for a compound air cooling heat exchanger with two or three heating fluids in parallel or in series. The control and measurement system is implemented based on a LabVIEW software platform, consisting of the data acquisition and process system, and the automotive operation and control system. By using advanced measuring instruments combined with sound computer software control, the testing system has characteristics of a compact structure, high accuracy, a wide range of testing scope and a friendly operation interface. The uncertainty of the total heat transfer coefficient K is less than 5%. The testing system provides a reliable performance testing platform for designing and developing new heat exchangers.
基金Projects(51575115,51775122)supported by the National Natural Science Foundation of China
文摘In view of the limitations of solid metal heat sink in the heat dissipation of high power light emitting diode （LED）, a kind of miniaturized phase change heat sink is developed for high power LED packaging. First, the fabrication process of miniaturized phase change heat sink is investigated, upon which all parts of the heat sink are fabricated including main-body and end-cover of the heat sink, the formation of three-dimensional boiling structures at the evaporation end, the sintering of the wick, and the encapsulation of high power LED phase change heat sink. Subsequently, with the assistance of the developed testing system, heat transfer performance of the heat sink is tested under the condition of natural convection, upon which the influence of thermal load and working medium on the heat transfer performance is investigated. Finally, the heat transfer performance of the developed miniaturized phase change heat sink is compared with that of metal solid heat sink. Results show that the developed miniaturized phase change heat sink presents much better heat transfer performance over traditional metal solid heat sink, and is suitable for the packaging of high power LED.
文摘To realize automatic control of automobile transmission performance test stand Methods The automatic control technique of the lubricant temperature,the program- controll- edautomaticshifting of the transmission,the continuous adjusting of revolution speed and load, data-acquisition and data real-time processing were adopted.Results The lubricant temperature was controlled at the set temperature ±2℃.The automatic shifting of the trans- mission is simple,reliable and accurate.The automatic adjusting of load and rotation speed is rapidandaccurate,the torque divergence is ±1N·m,the rotation speed divergence is ±5r/min Conclusion The four kinds of techniques are applied into the automobile transmission perfor- mance test stand successfully. mancetest stand successfully.
文摘he thermal performance test of the horizontal coaxial double tube hot gas duct (HGD) with an internal thermal insulation for the 10MW High Temperature Reactor Test Module (HTR10) was conducted on a Helium Test Loop(HETL). The present paper deals with the technical feature of the HETL, the test section and the thermal performance test of the HGD. The HGD test section with a triple tube structure includes an inner heater, a HGD model and a coldhot gas mixer. A counterflow of cold and hot helium gas under the pressure of about 3.0 MPa and the minimum temperature of 100℃ in the annular passage and the maximum of 950℃ in the central tube of the HGD model was formed. The HGD model was undergone 20 times of pressure cycle test under the pressure ranging from 0.1 to 3.4 MPa, 18 times of the temperature cycle test under the temperature ranging from 100 to 950℃ and high temperature (700 to 950℃) helium flow test for a period of more than 350 hours. The effective thermal conductivity (λeff) of the internal insulation of the HGD was investigated experimentally. The relationship of the effective thermal conductivity with the average tmperature of the internal insulation layer is λeff(W/m/℃)=0.3512+0.0003T(℃). The test results indicate that the HGD model has good abilities to resist heat flux from the central tube to the annular passage, temperature variations, and pressure variations.
文摘To improve the transmission accuracy and stiffness of the ball cycloid reducer, the authors developed a novel cycloid ball reducer, which uses a full complement ball as its gear teeth. Ceramic balls are used to get better performance in severe working conditions. A simple synthesis method was also found to determine the raceway forms and compute the contact forces among the balls and raceways. The Contact Stress Analysis (CSA) computer program was used to optimize the design of the reducer. In this paper, the following topics are covered: (1) Study of the geometry of the raceways. (2) Analyses of the principal curvature of the raceways are also accomplished. In addition, the modification of the raceway is put forward. (3) The contact forces and the reducer efficiency are evaluated. (4) Study of the performance of ceramic balls used in the CBR. A reducer using the above design technique was tested and the performances show that the reducer has high precision and rigidity. An increase of more than 50 percent transmission power was realized in the new gearing.
文摘Customizing applications through program configuration options has been proved by many open-source and commercial projects as one of the best practices in software engineering. However, traditional performance testing is not in synch with this industrial practice. Traditional performance testing techniques consider program inputs as the only external factor. It ignores the performance influence of configuration options. This study aims to stimulate research interest in performance testing in the context of configurable software systems by answering three research questions. That is, why it is necessary to conduct research in performance testing, what are the state-of-the-art techniques, and how do we conduct performance testing research in configurable software systems. In this study, we examine the unique characteristics and challenges of performance testing research in configurable software systems. We review and discuss research topics on the performance bug study, performance anti-patterns, program analysis, and performance testing. We share the research findings from the empirical study and outline the opening opportunities for new and advanced researchers to contribute to the research community.
基金Sponsored by Doctoral Research Fund of State Educational Commission of China
文摘The performance test of Intelligent Network (IN) system is an important phase in developing IN system. We designed a set of simple and practical methods on the basis of the characteristics of IN for the performance test of the prototype of the BUPT-IN system. The test result is well satisfied and shows that the performance of the BUPT-IN system reaches the original goal.
文摘Condenser is one of the important auxiliary equipments in nuclear power plants. The thermal efficiency of the entire unit was depended on the condenser performance. Cleanliness factor and condenser corrected pressure are the two most important evaluation indexes. The definition and derivation of these two evaluation indexes were elaborated and clarified in this paper. And the condenser performance at variable conditions was analyzed. The seawater temperature, pipe plugging rate and seawater volume rate effect on unit output was calculated. The calculation method was simple, which can provide reference guidance for similar power plant.
文摘Data consisting of test performance records of 725 bulls was analysed to evaluate trends for growth and feed efficiency, and to determine environmental factors that influence growth of range performance tested bulls in the arid sweet bushveld of South Africa. Performance data were subjected to regression procedures to estimate parameters of the slope (β) and intercept (α) for average daily gain (ADG) and Kleiber ratio (KR). Mixed procedures were applied to test for sources of variation in ADG and KR. There was an increase of 3.481 g/day/year and 0.528 g/day/ year in ADG for Nguni and Bonsmara bulls, respectively. The ADG trends’ respective feed efficiency as reflected by KR was 0.093 and 0.059. Herd of origin and test-year were the sources of variation for ADG while the variation in KR was due to the herd of origin, test-year, start-age and start-weight. Results indicated a steady increase in ADG and KR for range performance tested bulls in the arid sweet bushveld.
文摘In a performance test, the standards for assessing its test results are not sufficiently determined due to the lack of a well-structured test developing methods which are found in a functionality test. By extending the established workflow structure, this approach will concentrate on tradeoffs within T-workflow and further develop tests based on T-workflow. The monitoring and tuning point have also been investigated to understand the validity and performance of software. Finally through a case study, it has been shown that better assessment of software performance can be obtained with the suggested tests developed based on T-workflow and by locating its monitoring point and tuning point.
基金Supported by the National Natural Science Foundation of China(No.51205430)Chongqing Foundation and Frontier Project(No.cstc2016jcyjA0448)Chongqing Municipal Education Commission Scientific Research Project(No.KJ1600628)
文摘Based on the 1D-blade element momentum theory (BEM) with the improved tip loss correction introduced, a new aerodynamic model of wind turbine is developed. Using one high aerodynamic performance airfoil with 18% relative thickness, one small wind turbine blade is designed and the distribution of the chord and twist angle of the blade are determined. According to the shape parameters of the blade, a method to set up the 3D model is presented by investigating the coordinate position of each section of the blade. Based on the fiber reinforced polymer (FRP) molding technology, the manufacturing process of wind turbine blade is put forward. Using fiber reinforced polymer, the wind turbine blades are manufactured by the mold making and layer process. A test platform and method of wind turbine output power are carried out, the output powers at different speeds of the wind turbine are obtained and discussed. The comparison between the designed and one existing wind turbine rotor is completed to show the reliability and superiority of the design and test method presented in this paper.
基金Funded by National Natural Science Foundation of China (Grant No. 51078248)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘Two single-storey single-span reinforcement concrete （RC） frame structures strengthened with Y-eccentrically brace were designed and manufactured to be 1/3 scale. The pseudo-dynamic testing method was used to study the mechanical characteristics and the seismic performance under E1-Centro earthquake action with different peak acceleration adjusted by China＇s Code for Seismic Design of Buildings. The test results indicate that RC frame structures strengthened with Y- eccentrically steel brace present perfect seismic performance under strong earthquake action owing to the good ductility, strong bearing capability and fine energy absorbing capability provided by energy dissipation element and high lateral stiffness provided by diagonal braces. The seismic performance is also affected by the length of outsourcing steel at the joint between energy dissipation element of eccentric steel brace and RC frame beam. The joint should be considerably designed to make sure that shear failure can firstly occur in energy dissipation element.
基金Supported by the National S&T Major Project of China(No.ZX06901)the National Natural Science Foundation of China(No 11072131)
文摘Most materials can be easily corroded or ineffective in carbonaceous atmospheres at high temperatures in the reactor core of the high temperature gas-cooled reactor(HTGR).To solve the problem,a material performance test apparatus was built to provide reliable materials and technical support for relevant experiments of the HTGR.The apparatus uses a center high-purity graphite heater and surrounding thermal insulating layers made of carbon fiber felt to form a strong carbon reducing atmosphere inside the apparatus.Specially designed tungsten rhenium thermocouples which can endure high temperatures in carbonaceous atmospheres are used to control the temperature field.A typical experimental process was analyzed in the paper,which lasted 76 hours including seven stages.Experimental results showed the test apparatus could completely simulate the carbon reduction atmosphere and high temperature environment the same as that confronted in the real reactor and the performance of screened materials had been successfully tested and verified.Test temperature in the apparatus could be elevated up to 1600oC,which covered the whole temperature range of the normal operation and accident condition of HTGR and could fully meet the test requirements of materials used in the reactor.
