The main factors that influence the temperature field of frozen subgrade were analyzed.The experimental equipment for simulating frozen subgrade was built up,and the declining regulating tubes were placed at the foot ...The main factors that influence the temperature field of frozen subgrade were analyzed.The experimental equipment for simulating frozen subgrade was built up,and the declining regulating tubes were placed at the foot of the embankment. By means of this equipment two simulating experiments of controlling temperature filed of frozen sub- grade were carried out in the laboratory.One method is to collect natural cold energy,and the other one is to collect natural cold energy ccompanied by artificial refrigeration simultaneously.The result indicates that the latter is an ef- fective method for maintaining the stability of the frozen subgrade.展开更多
We investigate experimentally and analytically the combustion behavior of a high-metal magnesium-based hydro- reactive fuel under high temperature gaseous atmosphere. The fuel studied in this paper contains 73% magnes...We investigate experimentally and analytically the combustion behavior of a high-metal magnesium-based hydro- reactive fuel under high temperature gaseous atmosphere. The fuel studied in this paper contains 73% magnesium powders. An experimental system is designed and experiments are carried out in both argon and water vapor atmo- spheres. It is found that the burning surface temperature of the fuel is higher in water vapor than that in argon and both of them are higher than the melting point of magnesium, which indicates the molten state of magnesium particles in the burning surface of the fuel. Based on physical considerations and experimental results, a mathematical one-dimensional model is formulated to describe the combustion behavior of the high-metal magnesium-based hydro-reactive fuel. The model enables the evaluation of the burning surface temperature, the burning rate and the flame standoff distance each as a function of chamber pressure and water vapor concentration. The results predicted by the model show that the burning rate and the surface temperature increase when the chamber pressure and the water vapor concentration increase, which are in agreement with the observed experimental trends.展开更多
In this paper, the design of a virtual experiment system based on Flex and XML is described. The system adopts threelayer architecture and it is composed of four modules. Flex is used to design user interface, and XML...In this paper, the design of a virtual experiment system based on Flex and XML is described. The system adopts threelayer architecture and it is composed of four modules. Flex is used to design user interface, and XML is used as data format between layers or modules. Data services are used to store or retrieve the information of experiment components or experiment scenes. Principles for the design of simulation engine and simulation scheduler are discussed. The design of the simulation engine for ＂Digital Logic＂ course is described in detail. The system has been implemented in the experiment teaching of Digital Logic. Teaching results and the feedback from students demonstrate that the virtual experiment system can improve the effects of experiment teaching and arouse the learning interests of students.展开更多
基金Projects 2002CB412704 supported by the National Key Basic Research and Development Foundation of the Ministry of Sciences and Technology of China KZCX1-SW-04 supported by the Knowledge Innovation Program of the Chinese Academy of SciencesSKLFSE200304
文摘The main factors that influence the temperature field of frozen subgrade were analyzed.The experimental equipment for simulating frozen subgrade was built up,and the declining regulating tubes were placed at the foot of the embankment. By means of this equipment two simulating experiments of controlling temperature filed of frozen sub- grade were carried out in the laboratory.One method is to collect natural cold energy,and the other one is to collect natural cold energy ccompanied by artificial refrigeration simultaneously.The result indicates that the latter is an ef- fective method for maintaining the stability of the frozen subgrade.
基金Project supported by the Young Scientist Fund of the National Natural Science Foundation of China(Grant No.51006118)
文摘We investigate experimentally and analytically the combustion behavior of a high-metal magnesium-based hydro- reactive fuel under high temperature gaseous atmosphere. The fuel studied in this paper contains 73% magnesium powders. An experimental system is designed and experiments are carried out in both argon and water vapor atmo- spheres. It is found that the burning surface temperature of the fuel is higher in water vapor than that in argon and both of them are higher than the melting point of magnesium, which indicates the molten state of magnesium particles in the burning surface of the fuel. Based on physical considerations and experimental results, a mathematical one-dimensional model is formulated to describe the combustion behavior of the high-metal magnesium-based hydro-reactive fuel. The model enables the evaluation of the burning surface temperature, the burning rate and the flame standoff distance each as a function of chamber pressure and water vapor concentration. The results predicted by the model show that the burning rate and the surface temperature increase when the chamber pressure and the water vapor concentration increase, which are in agreement with the observed experimental trends.
基金Supported by the Key Project of the National Science and Technology Pillar Programs (2008BAH29B05, 2008BAH29B06)Education Reform Project in Hubei Province(2009052)
文摘In this paper, the design of a virtual experiment system based on Flex and XML is described. The system adopts threelayer architecture and it is composed of four modules. Flex is used to design user interface, and XML is used as data format between layers or modules. Data services are used to store or retrieve the information of experiment components or experiment scenes. Principles for the design of simulation engine and simulation scheduler are discussed. The design of the simulation engine for ＂Digital Logic＂ course is described in detail. The system has been implemented in the experiment teaching of Digital Logic. Teaching results and the feedback from students demonstrate that the virtual experiment system can improve the effects of experiment teaching and arouse the learning interests of students.
