The military situation of the thirteenth century required that the Song and the Mongols construct a great number of defensive works,relying on the mountains or facing the rivers,in the mountainous Sichuan Province and...The military situation of the thirteenth century required that the Song and the Mongols construct a great number of defensive works,relying on the mountains or facing the rivers,in the mountainous Sichuan Province and Chongqing.In recent years,a special kind of explosive firearms,huolei火雷(bombs),was unearthed in the large-scale excavations of the site of Diaoyu Fortress钓鱼城in Hechuan District合川and the Baidicheng白帝城in Fengjie County奉节,both of which were defensive works constructed in this mountainous area during the Southern Song dynasty.In addition,the ruins of kilns and the clay molds that were relevant to the casting of iron huolei have been discovered at the site of Baidicheng,indicating that these huolei might have been produced locally.The Southern Song iron huolei unearthed in Chongqing are the most direct evidence of the evolvement of gunpowder and firearms,and are of great significance to the history of science and technology,in particular the history of military technology.展开更多
A statistical signal processing technique was proposed and verified as independent component analysis(ICA) for fault detection and diagnosis of industrial systems without exact and detailed model.Actually,the aim is t...A statistical signal processing technique was proposed and verified as independent component analysis(ICA) for fault detection and diagnosis of industrial systems without exact and detailed model.Actually,the aim is to utilize system as a black box.The system studied is condenser system of one of MAPNA's power plants.At first,principal component analysis(PCA) approach was applied to reduce the dimensionality of the real acquired data set and to identify the essential and useful ones.Then,the fault sources were diagnosed by ICA technique.The results show that ICA approach is valid and effective for faults detection and diagnosis even in noisy states,and it can distinguish main factors of abnormality among many diverse parts of a power plant's condenser system.This selectivity problem is left unsolved in many plants,because the main factors often become unnoticed by fault expansion through other parts of the plants.展开更多
The first Chinese Mars exploration will fulfill the goals of ＂orbiting, landing and roving＂ in one mission. This paper briefly describes the process of international Mars exploration and analyzes the development of ...The first Chinese Mars exploration will fulfill the goals of ＂orbiting, landing and roving＂ in one mission. This paper briefly describes the process of international Mars exploration and analyzes the development of Chinese Mars exploration. It focuses on introducing the scientific significance and engineering difficulties of Mars exploration, and provides an overview of the system design of the probe, including the flight profile, the preliminary selection of the landing site, the entry, descent and landing （also known as EDL） process. Four types of key technologies, including telecommunications, autonomous control, the EDL process, and its structure and mechanism, are detailed in this paper. Finally, the paper highlights the expected scientific and engineering results of the mission.展开更多
The transverse injection flow field has an important impact on the flowpath design of scramjet engines. At present a combination of the transverse injection scheme and any other flame holder has been widely employed i...The transverse injection flow field has an important impact on the flowpath design of scramjet engines. At present a combination of the transverse injection scheme and any other flame holder has been widely employed in hypersonic propulsion systems to promote the mixing process between the fuel and the supersonic freestream; combustion efficiency has been improved thereby, as well as engine thrust. Research on mixing techniques for the transverse injection flow field is summarized from four aspects, namely the jet-to-crossflow pressure ratio, the geometric configuration of the injection port, the number of injection ports, and the injection angle. In conclusion, urgent investigations of mixing techniques of the transverse injection flow field are pro- posed, especiaUy data mining in the quantitative analytical results for transverse injection flow field, based on results from multi-objective design optimization theory.展开更多
The planetary radio occultation technique is one of the earliest suggested and achieved methods to detect the planetary atmosphere,and has been conducted by almost every deep space planetary probe.The principles,modul...The planetary radio occultation technique is one of the earliest suggested and achieved methods to detect the planetary atmosphere,and has been conducted by almost every deep space planetary probe.The principles,modules,inversion results and primary analysis of the SHAO Planetary Occultation observation Processing system(SPOPs) are presented in this paper.Utilizing open-loop and closed-loop Doppler residual data of the Mars Express radio occultation experiment provided by ESA PSA and NASA PDS,the temperature,pressure,molecular number density profiles of Martian atmosphere and electron density profiles of the ionosphere are successfully retrieved,and the results are validated by the released radio science level 04 products of the ESA MaRS group.This system can also process the atmosphere radio occultation observations of other planets and theirs natural satellites.The implementation of the planetary radio occultation technique is of significance to China's YH-1 Mars exploration project,as well as for future planetary exploration missions from China.展开更多
文摘The military situation of the thirteenth century required that the Song and the Mongols construct a great number of defensive works,relying on the mountains or facing the rivers,in the mountainous Sichuan Province and Chongqing.In recent years,a special kind of explosive firearms,huolei火雷(bombs),was unearthed in the large-scale excavations of the site of Diaoyu Fortress钓鱼城in Hechuan District合川and the Baidicheng白帝城in Fengjie County奉节,both of which were defensive works constructed in this mountainous area during the Southern Song dynasty.In addition,the ruins of kilns and the clay molds that were relevant to the casting of iron huolei have been discovered at the site of Baidicheng,indicating that these huolei might have been produced locally.The Southern Song iron huolei unearthed in Chongqing are the most direct evidence of the evolvement of gunpowder and firearms,and are of great significance to the history of science and technology,in particular the history of military technology.
基金Project(217/s/458)supported by Azarbaijan Shahid Madani University,Iran
文摘A statistical signal processing technique was proposed and verified as independent component analysis(ICA) for fault detection and diagnosis of industrial systems without exact and detailed model.Actually,the aim is to utilize system as a black box.The system studied is condenser system of one of MAPNA's power plants.At first,principal component analysis(PCA) approach was applied to reduce the dimensionality of the real acquired data set and to identify the essential and useful ones.Then,the fault sources were diagnosed by ICA technique.The results show that ICA approach is valid and effective for faults detection and diagnosis even in noisy states,and it can distinguish main factors of abnormality among many diverse parts of a power plant's condenser system.This selectivity problem is left unsolved in many plants,because the main factors often become unnoticed by fault expansion through other parts of the plants.
文摘The first Chinese Mars exploration will fulfill the goals of ＂orbiting, landing and roving＂ in one mission. This paper briefly describes the process of international Mars exploration and analyzes the development of Chinese Mars exploration. It focuses on introducing the scientific significance and engineering difficulties of Mars exploration, and provides an overview of the system design of the probe, including the flight profile, the preliminary selection of the landing site, the entry, descent and landing （also known as EDL） process. Four types of key technologies, including telecommunications, autonomous control, the EDL process, and its structure and mechanism, are detailed in this paper. Finally, the paper highlights the expected scientific and engineering results of the mission.
基金supported by the Science Foundation of National University of Defense Technology (No. JC11-01-02)the Hunan Provincial Natural Science Foundation of China (No.12jj4047)
文摘The transverse injection flow field has an important impact on the flowpath design of scramjet engines. At present a combination of the transverse injection scheme and any other flame holder has been widely employed in hypersonic propulsion systems to promote the mixing process between the fuel and the supersonic freestream; combustion efficiency has been improved thereby, as well as engine thrust. Research on mixing techniques for the transverse injection flow field is summarized from four aspects, namely the jet-to-crossflow pressure ratio, the geometric configuration of the injection port, the number of injection ports, and the injection angle. In conclusion, urgent investigations of mixing techniques of the transverse injection flow field are pro- posed, especiaUy data mining in the quantitative analytical results for transverse injection flow field, based on results from multi-objective design optimization theory.
基金supported by the Sino-Russian Cooperation "YH-1" Mars Exploration Project (Grant No. 2008AA12A209)the National High-tech Research and Development Program of China (Grant No. 2009AA122206, 2008AA12A210, 2009AA12Z319)the National Nataral Science Foundation of China (Grant No. 10973031)
文摘The planetary radio occultation technique is one of the earliest suggested and achieved methods to detect the planetary atmosphere,and has been conducted by almost every deep space planetary probe.The principles,modules,inversion results and primary analysis of the SHAO Planetary Occultation observation Processing system(SPOPs) are presented in this paper.Utilizing open-loop and closed-loop Doppler residual data of the Mars Express radio occultation experiment provided by ESA PSA and NASA PDS,the temperature,pressure,molecular number density profiles of Martian atmosphere and electron density profiles of the ionosphere are successfully retrieved,and the results are validated by the released radio science level 04 products of the ESA MaRS group.This system can also process the atmosphere radio occultation observations of other planets and theirs natural satellites.The implementation of the planetary radio occultation technique is of significance to China's YH-1 Mars exploration project,as well as for future planetary exploration missions from China.
