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91.
The analytical expression for the complex amplitude of light reflected from a wedge-shaped thin film is derived. For plane wave incidence, a simple ray tracing approach is used to calculate Goos-H(a|¨)nchen (GH) shifts; and for non-plane wave incidence, for example, a Gaussian beam, the angular spectrum approach of plane wave is used in simulation. The two approaches predict that a wedge-shaped thin film can produce large negative longitudinal GH shifts. Although the reflectivity is small near the condition... 相似文献
92.
SHANG Li & ZHANG HePing School of Information Science Engineering Lanzhou University Lanzhou China School of Mathematics Statistics 《中国科学 数学(英文版)》2010,(4)
It has been shown that a λ m-connected graph G has the property λ m (G)≤ξ m (G) for m≤3.But for m≥4,Bonsma et al.pointed out that in general the inequality λ m (G)≤ξ m (G) is no longer true.Recently Ou showed that any λ 4-connected graph G with order at least 11 has the property λ 4 (G)≤ξ 4 (G).In this paper,by investigating some structure properties of a λ m-connected graph G with λ m (G) ξ m (G),we obtain easily the above result.Furthermore,we show that every λ m-connected graph G with order greater than m(m-1) satisfies the inequality λ m (G)≤ξm (G) for m≥5.And by constructing some examples,we illustrate that our conditions are the best possible. 相似文献
93.
System calibration, which usually involves complicated and time-consuming procedures, is crucial for any three-dimensional (3D) shape measurement system based on vision. A novel improved method is proposed for accurate calibration of such a measurement system. The system accuracy is improved with considering the nonlinear measurement error created by the difference between the system model and real measurement environment. We use Levenberg-Marquardt optimization algorithm to compensate the error and get a good result. The improved method has a 50% improvement of re-projection accuracy compared with our previous method. The measurement accuracy is maintained well within 1.5% of the overall measurement depth range. 相似文献
94.
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
95.
WU GuoXiong State Key Laboratory of Ocean Engineering College of Naval Architecture Ocean Civil Engineering Shanghai Jiao Tong University Shanghai China 《中国科学:物理学 力学 天文学(英文版)》2011,(1)
The sloshing of inviscid liquid of stratified density in a rectangular tank is analyzed.As the flow is no longer irrotional,the governing equation is found to be quite different from the Laplace equation used for the liquid of constant density.In particular it contains terms of mixed temporal and spatial derivatives.The problem is solved based on the variable separation method and Laplace transform for the constant Vaisala-Brunt frequency.It is found that the stratification of density may have small effects... 相似文献
96.
外源一氧化氮对镉胁迫下番茄幼苗叶绿体保护作用的光谱学分析 总被引:1,自引:0,他引:1
镉(Cd)是重要的重金属污染源,一氧化氮(NO)是近年来发现的一种普遍存在于生物界的信使分子,研究表明其参与了植物对Cd胁迫的应答反应调控。文章用硝普纳(SNP)作为NO供体,向番茄幼苗喷洒100mol·L^-1SNP1d后加入50mol·L^-1Cd处理7d,取完全展开叶片,提取叶绿体进行光谱学研究,分别测定了叶绿体室温吸收光谱、叶绿体低温荧光光谱和DCPIP电子传递效率等指标,研究外源NO缓解Cd对叶绿体毒性的影响。结果发现,CA对叶绿素a、叶绿素b和类胡萝b素含量都有不同程度的降低,NO处理缓解了CA的影响,使叶绿体室温吸收光谱的吸收率提高;CA导致686nm处峰(PSII)偏移4nrn,峰值降低33%,734nm处峰值降低23%,外源NO缓解了Cd对光合系统的影响,使得叶绿体低温荧光光谱在686和734nm的峰值分别仅下降17%和100o;以DCPIP为人工电子受体,Cd处理的叶绿体中DCPIP还原速率较慢,光合电子传递(H2O→DCPIP)速率降低1.5倍,外源NO处理显著缓解了Cd对电子传递链的抑制,使其光合电子传递速率恢复到对照的水平。该研究可为NO处理增强植物对Cd胁迫的抗性提供理论依据。 相似文献
97.
98.
LIU HaiFeng LIU HaiYan & SONG WeiDong State Key Laboratory of Explosion Science Technology Beijing Institute of Technology Beijing China School of Civil Hydraulic Engineering Ningxia University Yinchuan School of Science 《中国科学:物理学 力学 天文学(英文版)》2010,(2)
This paper takes concrete as a four-phase composite made of the intact matrix and three mutually perpendicular groups of penny-shaped micro-cracks. The intact matrix is assumed to be elastic,homogeneous and isotropic,and the micro-cracks are penny-shaped. Combined with the failure mechanism of concrete subjected to impact loading,a dynamic constitutive model for concrete is developed based on Mori-Tanaka's average stress concept and Eshelby's equivalent inclusion theory. Experimental results show that concr... 相似文献
99.
WANG Cui ZHANG Quan ZHANG XiaoFeng LIU Jing & LIU WeiPing College of Biological Environmental Engineering Zhejiang University of Technology Hangzhou China Key Laboratory of Environmental Remediation Ecosystem Health Ministry of Education College of Environmental Resource Sciences Zhejiang University Hangzhou China 《中国科学:化学》2010,(5)
Synthetic pyrethroids(SPs) ,a family of chiral insecticides consisting of multiple stereoismers,have been regarded as estrogenic endocrine-disrupting chemicals(EDCs) .In this study,we applied the yeast two-hybrid and molecular docking(MD) assay to assess the enantioselective estrogenic activities of three commonly used SPs,bifenthrin(cis-BF) ,permethrin(PM) and fenvalerate(Fen) .The β-galactosidase analyses indicated that all of the testing pyrethroids displayed significant(p<0.05) enantioselectivity.The re... 相似文献
100.
LI Zhong WANG Hongjuan XI Hongxia XU Kefeng WEN Jun Research Institute of Chemical Engineering South China University of Technology Guangzhou 《Chinese Journal of Reactive Polymers》2001,(2)
1. INTRODUCTION In some cities of China, cancer and breath system diseases caused by the pollution of volatile organic compounds (VOCs) have been obviously increasing. The VOCs includes BTEX (benzene, toluene, ethylbenzene, and xylene), aldehydes, cresol, phenol, acetic acid, polynuclear aromatic hydrocarbons (PAHs), which have long-term human health implications. Emission of the VOCs has threatened the health of people seriously [1,2]. The pollution of the VOCs mostly hails from… 相似文献