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Performance analysis of acceleration resolution for radar signal

Science China(Technological Sciences) 2003年第5期46卷 449-458页

作者： ZHAO Hongzhong (赵宏钟) FU Qiang (付强) Key Laboratory of ATR National University of Defence Technology Changsha 410073 China Key Laboratory of ATR National University of Defence Technology Changsha 410073 China

The high acceleration of moving targets has brought severe problems in radar signal processing, such as the decrease in output signal-noise-ratio and the deterioration of Doppler resolution. This paper presents an acceleration ambiguity function (AAF) for characterizing the acceleration effects and the acceleration resolution property in radar signal processing. The definition of the acceleration resolution based on AAF is also presented. Using AAF as an analyzing tool, some factors are derived including the loss factor of output SNR, the broadening factor of Doppler resolution, and the optimal accumulative time (OPT) caused by acceleration in linear-phase matched filtering. The convergent property of quadratic-phase matched-filter for searching for and estimating the acceleration is discussed. The results and conclusions are helpful for the quantitative analysis of the acceleration effects on signal processing, and for evaluation of the performance of acceleration in radar signal waveform design.

关键词： acceleration, Doppler, ambiguity function, resolution.

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Vacuum heating of solid target irradiated by femtosecond laser pulses

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Science China(Physics,Mechanics & Astronomy) 2003年第1期46卷 71-77页

作者： DONG Quanli(董全力) ZHANG Jie(张杰) Laboratory of Optical Physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China Laboratory of Optical Physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China

The interaction of femtosecond laser pulses with solid targets was studied through experiments and particle-in-cell (PIC) simulations. It is proved that the vacuum heating and the inverse bremsstralung process are the main mechanisms of the laser pulse absorption under such conditions. The distribution of hot electrons and that of X-ray are found to have double-temperature structure, which is confirmed by PIC simulations. While the lower temperature is attributed to the resonant absorption, the higher one, however, is caused by the laser-induced electric field in the target normal direction. The time-integrated spectra ofthe reflected laser pulse shows that the mechanism of electron acceleration is determined by the plasma density profile.

关键词： vacuum heating, electron acceleration, harmonics.

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Accelerating Effect in Kerr-Newman-Kasuya Field

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Communications in Theoretical Physics 2002年第10期38卷 509-512页

作者： CAO Deng WANG Yong-Jiu Institute of Physics Hunan Normal University Changsha 410081 China Institute of Physics Hunan Normal University Changsha 410081 China

We have obtained expressions of the accelerating effect in Kerr-Newman Kasuya field. These expressionsinclude four parameters: mass m, angular momentum a, electric charge q, and magnetic charge φ. Furthermore we studyits special case (vi = 0). We get the following conclusion. In the gravitation field of souse mass with electric charge qand magnetic charge b, the acceleration of test particle has not only radial component but also transverse *** θ = 0, the acceleration is minimum, and when θ = π/2, the acceleration is maximum. Furthermore, we discussthe effects of electric charge q and magnetic charge φ respectively.

关键词： acceleration, magnetic charge, Kerr-Newman-Kasuya field

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Solution to Equivalent Power Element of a Six Degrees of Freedom Simulator

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Journal of Donghua University(English Edition) 2002年第3期19卷 63-67页

作者：赵强李洪人王栋梁 Mechatron. Eng. Coll. Harbin Inst. of Technol. Harbin 150001 China

The dynamical equation of a six degrees of freedom(DOF) Stewart-type simulator with load and impact force is derived. By associating the direct solution to acceleration with the inverse solution to force, an equivalent power element model of the simulator is further presented, which offers the basis for analysis and design of the control system of the simulator.

关键词： six DOF simulator, Stewart platform, direct solution to acceleration, Newton-Euler method, power element.

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PROGRESS IN HELIOSPHERIC PHYSICS

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空间科学学报 2002年第Z1期22卷 64-80页

作者： Feng Xueshang Center for Space Science and Applied Research The Chinese Academy of Sciences Beijing 100080 P.R. China

This is an overview of progresses in heliospheric physics made in China in the period of June, 2000 to May, 2002. The report is focused on theoretical studies,modelling and observational analysis of interplanetary physical phenomena, and consists of five sections: the acceleration and heating of the solar wind, corona structures, coronal mass ejections, magnetic reconnection phenomena, and in terplanetary transient phenomena. The main achievements made recently by Chinese scientists in related areas are simply listed in corresponding sections without any priority, only certain editorial consideration.

关键词： Solar wind acceleration, Coronal mass ejection, Interplanetary,Transient phenomena

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