Hydrogenated diamond-like carbon (DLC) films were deposited on Si substrate using plasma enhanced chemical vapor deposition(PECVD) technique with CH4 plus H2 as the feedstock. The tribological properties of the hydrog...Hydrogenated diamond-like carbon (DLC) films were deposited on Si substrate using plasma enhanced chemical vapor deposition(PECVD) technique with CH4 plus H2 as the feedstock. The tribological properties of the hydrogenated DLC films were measured on a ball-on-disk tribometer in different testing environments (humid air,dry air, dry O2, dry Ar and dry N2 ) sliding against Si3 N4 balls. The friction surfaces of the films and Si3 N4 balls were observed on a scanning electron microscope (SEM) and investigated by X-ray photoelectron spectroscopy (XPS). The results show that the tribological properties of the hydrogenated DLC films are strongly dependent on the testing environments. In dry Ar and dry N2 environments, the hydrogenated DLC films provide a superlow friction coefficient of about 0. 008 -0.01 and excellent wear resistance (wear life of above 56 km). In dry air and dry O2, the friction coefficient is increased to 0. 025 - 0.04 and the wear life is decreased to about 30 km. When sliding in moist air, the friction coefficient of the films is further increased to 0. 08 and the wear life is decreased to 10. 4 km. SEM and XPS analyses show that the tribological behaviors appear to rely on the transferred carbon-rich layer processes on the Si3 N4 balls and on the friction-induced oxidation of the films controlled by the nature of the testing environments.展开更多
In recent years,the application scenarios of electrical and electronic products have become increasingly diverse worldwide.The impact of climatic environmental tests on the performance of related products has attracte...In recent years,the application scenarios of electrical and electronic products have become increasingly diverse worldwide.The impact of climatic environmental tests on the performance of related products has attracted much attention,and formulating scientific and reasonable environmental test plans has become an important step to ensure product quality and reliability.展开更多
With the rapid development of social economy, the environmental protection issue has been paid more and more attention. The coordinated development of economy and environmental protection is also the theme advocated a...With the rapid development of social economy, the environmental protection issue has been paid more and more attention. The coordinated development of economy and environmental protection is also the theme advocated all along. At the present stage, there are still many economic benefits brought about at the cost of destroying the environment. While developing the economy, it is accompanied by environmental destruction such as waste water and waste gas emissions. This paper studies and analyzes the existing problems and countermeasures of environmental testing technology for reference.展开更多
With the development of our society and the progress of science and technology, our economy is in a stage of rapid development. However, China's rapid economic development has brought a series of hidden dangers to...With the development of our society and the progress of science and technology, our economy is in a stage of rapid development. However, China's rapid economic development has brought a series of hidden dangers to China's ecological environment development, which will seriously restrict China's sustainable development. Especially in some large cities, their garbage pollution, air pollution and water environment pollution are unprecedented serious, which has aroused people's extensive attention and general thinking on environmental problems. In order to make China's economic development get a virtuous circle and promote China's stable and green sustainable economic development, relevant government personnel are required to do a good job in environmental pollution supervision and formulate relevant environmental protection policies to fundamentally ensure the operation of China's environmental pollution treatment.展开更多
Over the years, the environmental protection work in our country has become increasingly difficult to do. Most people in our society are now paying attention to how to realize the sustainable development of our societ...Over the years, the environmental protection work in our country has become increasingly difficult to do. Most people in our society are now paying attention to how to realize the sustainable development of our society and economy, which is a problem that needs to be solved in our social development. Environmental testing is an indispensable core part of environmental protection work, and cannot be replaced. Advanced technology is used to measure the content standard of environmental pollutants, and comprehensive assessment is made on the environmental quality level and environmental pollution degree according to China's environmental protection parameters, laying a good foundation for the follow-up work of environmental protection.展开更多
Since the reform and opening up, with the development of economy, the rapid development of Chinas economy has destroyed the natural environment. In recent years, while China has put forward the sustainable development...Since the reform and opening up, with the development of economy, the rapid development of Chinas economy has destroyed the natural environment. In recent years, while China has put forward the sustainable development, the development must be accompanied by environmental protection and ecological balance. Therefore, special attention must be paid to its role in the environmental management process. On this basis, the application of environmental monitoring and its contribution to environmental management are briefly introduced.展开更多
With the continuous development of social economy, the environmental pollution problem in our country is becoming more and more serious. Therefore, we must strengthen the environmental protection and maintain the ecol...With the continuous development of social economy, the environmental pollution problem in our country is becoming more and more serious. Therefore, we must strengthen the environmental protection and maintain the ecological environment in an all-round way. In the process of carrying out environmental protection work, the most indispensable and important component is environmental testing, which plays a multifaceted role. It not only plays an important role in environmental protection, but also plays an important and positive role in economic environment and people's health. With the deterioration of environmental problems, the role of environmental testing is more prominent. Environmental testing is a new research science with obvious comprehensive advantages and rich scientific contents. This is a very important driving force in the process of urban economic development. Relevant departments should pay more attention to environmental testing. From the actual point of view, appropriate and effective environmental protection measures should be taken to protect the ecological environment and promote the harmonious coexistence of man and nature.展开更多
China's rapid economic development has brought severe environmental pollution problems. At present, China's environmental protection cause has attracted more and more attention from all walks of life. Environm...China's rapid economic development has brought severe environmental pollution problems. At present, China's environmental protection cause has attracted more and more attention from all walks of life. Environmental testing technology refers to the process of comprehensive evaluation of environmental quality, which should make full use of physical and chemical technology and biological technology to timely and comprehensively determine the pollutants in the environment. The non-compliance of resource allocation with the standards will lead to the imperfection of environmental testing data. At present, the hardware equipment of environmental monitoring technology in our country is relatively backward and cannot provide more accurate and reliable testing data.展开更多
The current serious environmental pollution problem has seriously hindered the process of harmonious development between man and nature. Therefore, in order to further promote the harmonious development of man and nat...The current serious environmental pollution problem has seriously hindered the process of harmonious development between man and nature. Therefore, in order to further promote the harmonious development of man and nature, it is necessary to properly complete the environmental inspection work and effectively improve the environmental monitoring technology. At the same time, it is necessary to perfect and formulate relevant testing systems so that the environmental governance work can be relied on. The Environmental Protection Law stipulates that the subjective department of environmental protection administration under the State Council must establish an effective and perfect monitoring system, set scientific testing standards, and jointly establish an environmental testing network to improve the effectiveness of environmental management.展开更多
Environmental problems have always been a topic of great importance in the development of our country. In the environmental quality inspection, the application of chemical analysis method is a common way to grasp the ...Environmental problems have always been a topic of great importance in the development of our country. In the environmental quality inspection, the application of chemical analysis method is a common way to grasp the situation of ecological environmental pollution. The practical application of chemical analysis method in environmental detection is mainly to ensure the scientific and rigorous detection data of ecological environment, obtain practical and effective analysis data, establish environmental control measures, and then ensure the health of national living environment. This paper analyzes the application of chemical analysis methods in environmental detection, briefly describes the common chemical detection methods, and discusses the role of chemical analysis methods in environmental detection.展开更多
At present, the problem of environmental loss is becoming more and more serious. In order to realize the sustainable development of the environment, it is necessary to increase the research of environmental monitoring...At present, the problem of environmental loss is becoming more and more serious. In order to realize the sustainable development of the environment, it is necessary to increase the research of environmental monitoring technology. If the environment is polluted, it will bring a series of chain reactions. If the specific pollution problem cannot be effectively controlled in a timely manner, it will seriously damage the entire ecosystem. At the same time, it will be irreversible. The environment on which people depend for their survival will also be adversely affected. If it continues to develop for a long time, it will be very disadvantageous to the development of the national economy as a whole. Based on this, this article focuses on the in-depth research and analysis of environmental testing technology and ecological sustainable development.展开更多
Robustness testing for safety-critical embedded software is still a challenge in its nascent stages. In this paper, we propose a practical methodology and implement an environment by employing model-based robustness t...Robustness testing for safety-critical embedded software is still a challenge in its nascent stages. In this paper, we propose a practical methodology and implement an environment by employing model-based robustness testing for embedded software systems. It is a system-level black-box testing approach in which the fault behaviors of embedded software is triggered with the aid of modelbased fault injection by the support of an executable model-driven hardware-in-loop （HIL） testing environment. The prototype implementation of the robustness testing environment based on the proposed approach is experimentally discussed and illustrated by industrial case studies based on several avionics-embedded software systems. The results show that our proposed and implemented robustness testing method and environment are effective to find more bugs, and reduce burdens of testing engineers to enhance efficiency of testing tasks, especially for testing complex embedded systems.展开更多
Outfield testing is an effective measure to check the performance of wireless networks and facilities.Current outfield testing environment has inherent fluctuation due to the wireless propagation condition and has oth...Outfield testing is an effective measure to check the performance of wireless networks and facilities.Current outfield testing environment has inherent fluctuation due to the wireless propagation condition and has other disadvantages such as nonsupport for multiple scenarios,and low-level yet high-cost auto-control capability.In this paper,the conception of a radio testing environment,known as T-Ring(Integrated-Testing Ring),is proposed.It is based on a novel fitting degree evaluation frame.The testing ring can achieve high level of fitting degree to the real network so that the fluctuation of the wireless environment will be under control or even eliminated.This paper will choose some typical performance indicators and obtain corresponding statistical data in both the real network and system level simulation.A complete set of procedures is also given in this paper to evaluate the fitting degree of testing results and simulation results.It proves that the simulation highly fits to the real network and the simulation configuration can be used to construct the testing ring.At the same time,the advanced radio testing ring integrates multiple radio access technologies,scenarios and facilities from different manufacturers.It can improve the efficiency of wireless outfield testing and lower the cost of operators and manufacturers.展开更多
To meet the considerably increase of mobile data traffic and wireless communication connections around 2020,the 5th generation(5G)mobile network will necessarily consider more frequency bands,enabling technologies and...To meet the considerably increase of mobile data traffic and wireless communication connections around 2020,the 5th generation(5G)mobile network will necessarily consider more frequency bands,enabling technologies and diversified key performance indicators and test environments comparing with existing network,for example Long Term Evolution.More specifically,the obvious difference between 5G and previous wireless communication system are not only included eMBB(enhance mobile broadband) usage scenario,but also introduced mMTC(massive machine type communications)and URLLC(ultra-reliable and low latency communications) usage scenarios.Hence,in order to evaluate 5G related technologies,some novel test environments will be widely discussed,as well as,certain new key performance indicators will be drawn into5 G evaluation methodology for satisfied new requirements.We will discuss characteristic of these 4 candidate test environments,such as indoor isolated environment,high speed train environment;and the definition of 15 keys performance indicator will be explained and clarified,for example,Throughput,Network Energy Efficiency,Device Connection Density and so on.Furthermore,high-level assessment method of each test environment also will be initially considered.It is notable that an initial evaluation of indoor isolated environment also can be found,which the results show that there are 3 times average cell spectral efficiency than IMT-advanced's in same test environment.展开更多
The structure and characteristics of a large multi-parameter environmental simulation cabin are introduced.Due to the diffculties of control methods and the easily damaged characteristics,control systems for the large...The structure and characteristics of a large multi-parameter environmental simulation cabin are introduced.Due to the diffculties of control methods and the easily damaged characteristics,control systems for the large multi-parameter environmental simulation cabin are diffcult to be controlled quickly and accurately with a classical PID algorithm.Considering the dynamic state characteristics of the environmental simulation test chamber,a lumped parameter model of the control system is established to accurately control the multiple parameters of the environmental chamber and a fuzzy control algorithm combined with expert-PID decision is introduced into the temperature,pressure,and rotation speed control systems.Both simulations and experimental results have shown that compared with classical PID control,this fuzzy-expert control method can decrease overshoot as well as enhance the capacity of anti-dynamic disturbance with robustness.It can also resolve the contradiction between rapidity and small overshoot,and is suitable for application in a large multi-parameter environmental simulation cabin control system.展开更多
Environmental stress screening (ESS) is a technological process to reduce the costly early field failure of electronic components. This paper builds an optimization model for ESS of electronic components to obtain the...Environmental stress screening (ESS) is a technological process to reduce the costly early field failure of electronic components. This paper builds an optimization model for ESS of electronic components to obtain the optimal ESS duration. The failure phenomena of ESS are modeled by mixed distribution, and optimal ESS duration is defined by maximizing life-cycle cost savings under the condition of meeting reliability requirement.展开更多
This paper investigates the effect of drying environment, i.e. temperature and relative humidity, on the engineering properties and microscopic pore size distribution of an expansive soil. The shrinkage tests under di...This paper investigates the effect of drying environment, i.e. temperature and relative humidity, on the engineering properties and microscopic pore size distribution of an expansive soil. The shrinkage tests under different drying temperatures and relative humidity are carried out in a constant climate chamber. Then, the undisturbed samples, prepared in different drying environment, are used for the triaxial tests and mercury intrusion tests. It is found that the drying environment has noticeable influence on the engineering properties of expansive soils and it can be characterized by the drying rate. The linear shrinkage and strength increase with the decrease of the drying rate. The non-uniform deformation tends to happen in the high drying rate, which subsequently furthers the development of cracks. In addition, during the drying process, the variation of pores mainly focuses on the inter-aggregate pores and inter-particle pores. The lower drying rate leads to larger variation of pore size distribution.展开更多
The need for efficient and reproducible development processes for sensor and perception systems is growing with their increased use in modern vehicles. Such processes can be achieved by using virtual test environments...The need for efficient and reproducible development processes for sensor and perception systems is growing with their increased use in modern vehicles. Such processes can be achieved by using virtual test environments and virtual sensor models. In the context of this, the present paper documents the development of a sensor model for depth estimation of virtual three-dimensional scenarios. For this purpose, the geometric and algorithmic principles of stereoscopic camera systems are recreated in a virtual form. The model is implemented as a subroutine in the Epic Games Unreal Engine, which is one of the most common Game Engines. Its architecture consists of several independent procedures that enable a local depth estimation, but also a reconstruction of a whole three-dimensional scenery. In addition, a separate programme for calibrating the model is presented. In addition to the basic principles, the architecture and the implementation, this work also documents the evaluation of the model created. It is shown that the model meets specifically defined requirements for real-time capability and the accuracy of the evaluation. Thus, it is suitable for the virtual testing of common algorithms and highly automated driving functions.展开更多
Based on the experience of environmental acceptance tests for power transmission projects, the problems found in acceptance tests and the system shortcomings of acceptance test itself are analyzed. Recommendations are...Based on the experience of environmental acceptance tests for power transmission projects, the problems found in acceptance tests and the system shortcomings of acceptance test itself are analyzed. Recommendations are provided to improve the future work.展开更多
With the rapid development of national economy and medical science and technology;Environmental chemical testing equipment covers the testing conditions of environmental testing equipment closely related;Environmental...With the rapid development of national economy and medical science and technology;Environmental chemical testing equipment covers the testing conditions of environmental testing equipment closely related;Environmental drying furnace and other enterprises;Moisturizing of thermostat and incubator;And jointly by the unit testing equipment enterprise production technology and research institutions. In order to correctly carry out the technical test of the reliability test product;Each test technology environmental test equipment basically itself must comply with the specified conditions of use;The environment for testing the technical performance of the product;To ensure an efficient test environment. Test the value of the product. It is usually used for batch testing the quality and reliability of similar products;Study whether there are quality defects in product design and mass production. However;The management of temperature calibration requires a lot of time and effort and it's a lot of work. Under the conditions of temperature management of environmental chemical test equipment;it is necessary to sample and measure the temperature at various points in the test chamber several times. Accurately measure the deviation of temperature management parameters at each point and calibrate it;Therefore, a quasi-accurate calibration management method of point temperature parameter deviation measurement is also an urgent problem to be solved in the temperature management technology field of environmental chemistry test equipment in China.展开更多
基金Projects(59925513 50323007) supported by the National Natural Science Foundation of China+1 种基金 Project(2003AA305670) supported by Hi-tech Research and Development Program of China Project supported by the "Top Hundred Talents Program" of Chinese Academy of Sciences
文摘Hydrogenated diamond-like carbon (DLC) films were deposited on Si substrate using plasma enhanced chemical vapor deposition(PECVD) technique with CH4 plus H2 as the feedstock. The tribological properties of the hydrogenated DLC films were measured on a ball-on-disk tribometer in different testing environments (humid air,dry air, dry O2, dry Ar and dry N2 ) sliding against Si3 N4 balls. The friction surfaces of the films and Si3 N4 balls were observed on a scanning electron microscope (SEM) and investigated by X-ray photoelectron spectroscopy (XPS). The results show that the tribological properties of the hydrogenated DLC films are strongly dependent on the testing environments. In dry Ar and dry N2 environments, the hydrogenated DLC films provide a superlow friction coefficient of about 0. 008 -0.01 and excellent wear resistance (wear life of above 56 km). In dry air and dry O2, the friction coefficient is increased to 0. 025 - 0.04 and the wear life is decreased to about 30 km. When sliding in moist air, the friction coefficient of the films is further increased to 0. 08 and the wear life is decreased to 10. 4 km. SEM and XPS analyses show that the tribological behaviors appear to rely on the transferred carbon-rich layer processes on the Si3 N4 balls and on the friction-induced oxidation of the films controlled by the nature of the testing environments.
文摘In recent years,the application scenarios of electrical and electronic products have become increasingly diverse worldwide.The impact of climatic environmental tests on the performance of related products has attracted much attention,and formulating scientific and reasonable environmental test plans has become an important step to ensure product quality and reliability.
文摘With the rapid development of social economy, the environmental protection issue has been paid more and more attention. The coordinated development of economy and environmental protection is also the theme advocated all along. At the present stage, there are still many economic benefits brought about at the cost of destroying the environment. While developing the economy, it is accompanied by environmental destruction such as waste water and waste gas emissions. This paper studies and analyzes the existing problems and countermeasures of environmental testing technology for reference.
文摘With the development of our society and the progress of science and technology, our economy is in a stage of rapid development. However, China's rapid economic development has brought a series of hidden dangers to China's ecological environment development, which will seriously restrict China's sustainable development. Especially in some large cities, their garbage pollution, air pollution and water environment pollution are unprecedented serious, which has aroused people's extensive attention and general thinking on environmental problems. In order to make China's economic development get a virtuous circle and promote China's stable and green sustainable economic development, relevant government personnel are required to do a good job in environmental pollution supervision and formulate relevant environmental protection policies to fundamentally ensure the operation of China's environmental pollution treatment.
文摘Over the years, the environmental protection work in our country has become increasingly difficult to do. Most people in our society are now paying attention to how to realize the sustainable development of our society and economy, which is a problem that needs to be solved in our social development. Environmental testing is an indispensable core part of environmental protection work, and cannot be replaced. Advanced technology is used to measure the content standard of environmental pollutants, and comprehensive assessment is made on the environmental quality level and environmental pollution degree according to China's environmental protection parameters, laying a good foundation for the follow-up work of environmental protection.
文摘Since the reform and opening up, with the development of economy, the rapid development of Chinas economy has destroyed the natural environment. In recent years, while China has put forward the sustainable development, the development must be accompanied by environmental protection and ecological balance. Therefore, special attention must be paid to its role in the environmental management process. On this basis, the application of environmental monitoring and its contribution to environmental management are briefly introduced.
文摘With the continuous development of social economy, the environmental pollution problem in our country is becoming more and more serious. Therefore, we must strengthen the environmental protection and maintain the ecological environment in an all-round way. In the process of carrying out environmental protection work, the most indispensable and important component is environmental testing, which plays a multifaceted role. It not only plays an important role in environmental protection, but also plays an important and positive role in economic environment and people's health. With the deterioration of environmental problems, the role of environmental testing is more prominent. Environmental testing is a new research science with obvious comprehensive advantages and rich scientific contents. This is a very important driving force in the process of urban economic development. Relevant departments should pay more attention to environmental testing. From the actual point of view, appropriate and effective environmental protection measures should be taken to protect the ecological environment and promote the harmonious coexistence of man and nature.
文摘China's rapid economic development has brought severe environmental pollution problems. At present, China's environmental protection cause has attracted more and more attention from all walks of life. Environmental testing technology refers to the process of comprehensive evaluation of environmental quality, which should make full use of physical and chemical technology and biological technology to timely and comprehensively determine the pollutants in the environment. The non-compliance of resource allocation with the standards will lead to the imperfection of environmental testing data. At present, the hardware equipment of environmental monitoring technology in our country is relatively backward and cannot provide more accurate and reliable testing data.
文摘The current serious environmental pollution problem has seriously hindered the process of harmonious development between man and nature. Therefore, in order to further promote the harmonious development of man and nature, it is necessary to properly complete the environmental inspection work and effectively improve the environmental monitoring technology. At the same time, it is necessary to perfect and formulate relevant testing systems so that the environmental governance work can be relied on. The Environmental Protection Law stipulates that the subjective department of environmental protection administration under the State Council must establish an effective and perfect monitoring system, set scientific testing standards, and jointly establish an environmental testing network to improve the effectiveness of environmental management.
文摘Environmental problems have always been a topic of great importance in the development of our country. In the environmental quality inspection, the application of chemical analysis method is a common way to grasp the situation of ecological environmental pollution. The practical application of chemical analysis method in environmental detection is mainly to ensure the scientific and rigorous detection data of ecological environment, obtain practical and effective analysis data, establish environmental control measures, and then ensure the health of national living environment. This paper analyzes the application of chemical analysis methods in environmental detection, briefly describes the common chemical detection methods, and discusses the role of chemical analysis methods in environmental detection.
文摘At present, the problem of environmental loss is becoming more and more serious. In order to realize the sustainable development of the environment, it is necessary to increase the research of environmental monitoring technology. If the environment is polluted, it will bring a series of chain reactions. If the specific pollution problem cannot be effectively controlled in a timely manner, it will seriously damage the entire ecosystem. At the same time, it will be irreversible. The environment on which people depend for their survival will also be adversely affected. If it continues to develop for a long time, it will be very disadvantageous to the development of the national economy as a whole. Based on this, this article focuses on the in-depth research and analysis of environmental testing technology and ecological sustainable development.
基金the Aeronautics Science Foundation of China(No.2011ZD51055)Science and Technology on Reliability&Environmental Engineering Laboratory(No.302367)the National Pre-Research Foundation of China(No.51319080201)
文摘Robustness testing for safety-critical embedded software is still a challenge in its nascent stages. In this paper, we propose a practical methodology and implement an environment by employing model-based robustness testing for embedded software systems. It is a system-level black-box testing approach in which the fault behaviors of embedded software is triggered with the aid of modelbased fault injection by the support of an executable model-driven hardware-in-loop （HIL） testing environment. The prototype implementation of the robustness testing environment based on the proposed approach is experimentally discussed and illustrated by industrial case studies based on several avionics-embedded software systems. The results show that our proposed and implemented robustness testing method and environment are effective to find more bugs, and reduce burdens of testing engineers to enhance efficiency of testing tasks, especially for testing complex embedded systems.
文摘Outfield testing is an effective measure to check the performance of wireless networks and facilities.Current outfield testing environment has inherent fluctuation due to the wireless propagation condition and has other disadvantages such as nonsupport for multiple scenarios,and low-level yet high-cost auto-control capability.In this paper,the conception of a radio testing environment,known as T-Ring(Integrated-Testing Ring),is proposed.It is based on a novel fitting degree evaluation frame.The testing ring can achieve high level of fitting degree to the real network so that the fluctuation of the wireless environment will be under control or even eliminated.This paper will choose some typical performance indicators and obtain corresponding statistical data in both the real network and system level simulation.A complete set of procedures is also given in this paper to evaluate the fitting degree of testing results and simulation results.It proves that the simulation highly fits to the real network and the simulation configuration can be used to construct the testing ring.At the same time,the advanced radio testing ring integrates multiple radio access technologies,scenarios and facilities from different manufacturers.It can improve the efficiency of wireless outfield testing and lower the cost of operators and manufacturers.
文摘To meet the considerably increase of mobile data traffic and wireless communication connections around 2020,the 5th generation(5G)mobile network will necessarily consider more frequency bands,enabling technologies and diversified key performance indicators and test environments comparing with existing network,for example Long Term Evolution.More specifically,the obvious difference between 5G and previous wireless communication system are not only included eMBB(enhance mobile broadband) usage scenario,but also introduced mMTC(massive machine type communications)and URLLC(ultra-reliable and low latency communications) usage scenarios.Hence,in order to evaluate 5G related technologies,some novel test environments will be widely discussed,as well as,certain new key performance indicators will be drawn into5 G evaluation methodology for satisfied new requirements.We will discuss characteristic of these 4 candidate test environments,such as indoor isolated environment,high speed train environment;and the definition of 15 keys performance indicator will be explained and clarified,for example,Throughput,Network Energy Efficiency,Device Connection Density and so on.Furthermore,high-level assessment method of each test environment also will be initially considered.It is notable that an initial evaluation of indoor isolated environment also can be found,which the results show that there are 3 times average cell spectral efficiency than IMT-advanced's in same test environment.
基金supported by the Aeronautical Science Foundation of China(No.2012ZD51043)‘‘Fanzhou’’ Youth Scientifc Funds(No.20100504)
文摘The structure and characteristics of a large multi-parameter environmental simulation cabin are introduced.Due to the diffculties of control methods and the easily damaged characteristics,control systems for the large multi-parameter environmental simulation cabin are diffcult to be controlled quickly and accurately with a classical PID algorithm.Considering the dynamic state characteristics of the environmental simulation test chamber,a lumped parameter model of the control system is established to accurately control the multiple parameters of the environmental chamber and a fuzzy control algorithm combined with expert-PID decision is introduced into the temperature,pressure,and rotation speed control systems.Both simulations and experimental results have shown that compared with classical PID control,this fuzzy-expert control method can decrease overshoot as well as enhance the capacity of anti-dynamic disturbance with robustness.It can also resolve the contradiction between rapidity and small overshoot,and is suitable for application in a large multi-parameter environmental simulation cabin control system.
文摘Environmental stress screening (ESS) is a technological process to reduce the costly early field failure of electronic components. This paper builds an optimization model for ESS of electronic components to obtain the optimal ESS duration. The failure phenomena of ESS are modeled by mixed distribution, and optimal ESS duration is defined by maximizing life-cycle cost savings under the condition of meeting reliability requirement.
基金financially supported by the National Natural Science Foundation of China (Grant No. 41430634)the State Key Laboratory of Geomechanics and Geotechnical Engineering (Grant No. Y11002)
文摘This paper investigates the effect of drying environment, i.e. temperature and relative humidity, on the engineering properties and microscopic pore size distribution of an expansive soil. The shrinkage tests under different drying temperatures and relative humidity are carried out in a constant climate chamber. Then, the undisturbed samples, prepared in different drying environment, are used for the triaxial tests and mercury intrusion tests. It is found that the drying environment has noticeable influence on the engineering properties of expansive soils and it can be characterized by the drying rate. The linear shrinkage and strength increase with the decrease of the drying rate. The non-uniform deformation tends to happen in the high drying rate, which subsequently furthers the development of cracks. In addition, during the drying process, the variation of pores mainly focuses on the inter-aggregate pores and inter-particle pores. The lower drying rate leads to larger variation of pore size distribution.
文摘The need for efficient and reproducible development processes for sensor and perception systems is growing with their increased use in modern vehicles. Such processes can be achieved by using virtual test environments and virtual sensor models. In the context of this, the present paper documents the development of a sensor model for depth estimation of virtual three-dimensional scenarios. For this purpose, the geometric and algorithmic principles of stereoscopic camera systems are recreated in a virtual form. The model is implemented as a subroutine in the Epic Games Unreal Engine, which is one of the most common Game Engines. Its architecture consists of several independent procedures that enable a local depth estimation, but also a reconstruction of a whole three-dimensional scenery. In addition, a separate programme for calibrating the model is presented. In addition to the basic principles, the architecture and the implementation, this work also documents the evaluation of the model created. It is shown that the model meets specifically defined requirements for real-time capability and the accuracy of the evaluation. Thus, it is suitable for the virtual testing of common algorithms and highly automated driving functions.
文摘Based on the experience of environmental acceptance tests for power transmission projects, the problems found in acceptance tests and the system shortcomings of acceptance test itself are analyzed. Recommendations are provided to improve the future work.
文摘With the rapid development of national economy and medical science and technology;Environmental chemical testing equipment covers the testing conditions of environmental testing equipment closely related;Environmental drying furnace and other enterprises;Moisturizing of thermostat and incubator;And jointly by the unit testing equipment enterprise production technology and research institutions. In order to correctly carry out the technical test of the reliability test product;Each test technology environmental test equipment basically itself must comply with the specified conditions of use;The environment for testing the technical performance of the product;To ensure an efficient test environment. Test the value of the product. It is usually used for batch testing the quality and reliability of similar products;Study whether there are quality defects in product design and mass production. However;The management of temperature calibration requires a lot of time and effort and it's a lot of work. Under the conditions of temperature management of environmental chemical test equipment;it is necessary to sample and measure the temperature at various points in the test chamber several times. Accurately measure the deviation of temperature management parameters at each point and calibrate it;Therefore, a quasi-accurate calibration management method of point temperature parameter deviation measurement is also an urgent problem to be solved in the temperature management technology field of environmental chemistry test equipment in China.
