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191.
Relative position determination of a lunar rover using high-accuracy multi-frequency same-beam VLBI 总被引:2,自引:0,他引:2
LIU QingHui CHEN Ming XIONG WeiMing QIAN ZhiHan LI JinLing HAO WangHong WANG GuangLi ZHENG WeiMin GUAN Di ZHU RenJie WANG WeiHua ZHANG XiuZhong JIANG DongRong SHU FengChun PING JinSong & HONG XiaoYu Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai China Center for Space Science Applied Research Beijing Lunar Explorer Engineering General Department Beijing ... 《中国科学:物理学 力学 天文学(英文版)》2010,(3)
Multi-frequency same-beam VLBI means that two explorers with a small separation angle are simultaneously observed with the main beam of receiving antennas. In the same-beam VLBI, the differential phase delay between two explorers and two receiving telescopes can be obtained with a small error of several picoseconds. The differential phase delay, as the observable of the same-beam VLBI, gives the separation angular information of the two explorers in the celestial sphere. The two-dimensional relative position on the plane-of-sky can thus be precisely determined with an error of less than 1 m for a distance of 3.8×105 km far away from the earth, by using the differential phase delay obtained with the four Chinese VLBI stations. The relative position of a lunar rover on the lunar surface can be determined with an error of 10 m by using the differential phase delay data and the range data for the lander when the lunar topography near the rover and the lander can be determined with an error of 10 m. 相似文献
192.
本文简要介绍了计算C G系数的生群元矩阵方程法,给出计算二十面体群C G系数时采用的简化计算方法,并给出了Ⅰ群C G系数的计算结果。 相似文献
193.
The Anomalous Effect of Interface Traps on Generation Current in Lightly Doped Drain nMOSFET's
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The anomalous phenomenon of generation current ICD in the lightly doped drain (LDD) nMOSFET measured under the drain bias VD-step mode is reported. We propose an assumption of activated (A) and frozen (F) traps for the VD-step mode: The A traps contributes to ICD while the F process can make them lose the roles as generation centers. The A and F regions can form the F-A region. The comparison of the F and A regions decides the role of the F-A region. The experiments confirm the assumption. 相似文献
194.
讨论了一类三种群Beddington-DeAngelis反应食物链模型,其中第一个种群具有两阶段结构,且第二个种群对第一个种群有阶段偏食现象,得到了系统的一致持久性,进一步证明了在适当条件下,周期解及概周期解的存在性和全局渐近稳定性. 相似文献
195.
196.
Aiming to provide an appropriate number K of clusters, in this paper, we propose a new criterion function - H criterion function, whose three properties have also been proved. We validate the performance of the H criterion function on one artificial dataset and three real-world datasets, and the results are almostly consistent with a previous method. The nonparametric criterion we proposed is intuitive, simple and the computational cost is acceptable. 相似文献
197.
Lasers and amplifiers in a single fiber have been developed rapidly, especially for optical fiber communication and various sensors, in the recent years. However, remarkable progress and achievement have been made mainly in silica fiber doped with rare earth elements. In this paper, we report the progress on the development of the Yb3+-doped phosphate fiber laser. 相似文献
198.
Straightness Measurement Using Laser Diode and CCD Camera 总被引:4,自引:0,他引:4
HAO Qun ZHAO Yang LI Dacheng CAO Mang 《Chinese Journal of Lasers》1999,8(3):215-220
1IntroductionInmanufactureandasembleofmodernmachinesandinstruments,anindispensablerequirementisthecontrolofformandpositionero... 相似文献
199.
Hong Ping HE Yue Mao SHEN Guo Ying ZUO Wei Ming ZHU Xiao Sheng YANG Xiao Jiang HAO 《中国化学快报》2000,11(6)
Cla!tsenaexcavataBurm.f(Rutaceae)isabushwidelydistributedinYunnan,China.Leavesandbarksofthisplanthavebeenusedasfolkrnedicineforthetreatmentofdysentery,enteritis,andurethrainfection1.ClalISenaspeciesareknowntobetherichsourcesofcarbazolealkaloidsandcoumarins=-j.TheconstituentsofCexcavalacollectedinXishuangbannahavebeenstudied'andthispaperdescribestheisolationandstructureelucidationoftwonewO-terpenoidalcoumarins,excavacoumarinA(2)andexcavacoumarinB(3),andthel3CNMRspectraldataassignmentsfora… 相似文献
200.
The dynamic properties of the assistant sounders in the black cicada are given and the twitching properties of Contraction in the sounding muscle are revealed in this paper.For the operculum, tymbal cover and joint membrane, each of their vibration periods consists of three subgroup vibrations (SGV_(a,b,c)) corresponding to amplitude-modulation pulse trains (AMPT_(1,2,3)) in every syllable of synchro song. In comparison with the vibration at dorsum, the SGV_(a-c) have a subband with the function of regulating the tone. During calling song continuously, the pressure change inside the resonant cavity and the airspeed through the spiracles on both sides are about 7. 94—15.88 Paand 0.59—0.84 cm~3/s respectively, and they increase by about 7 and 2.6 times as the abdomen is moved. When the contraction motion of the sounding muscle comes up to the critical Sounding state, it further produces the twitching process, and drives the sounding membrane and the toning plate-membrane to produce AMPT_(1-3) and SGV_(a 相似文献