桁架结构系统可靠度的敏度分析

基于结构系统可靠性分析的高精度公式和PNET法,导出了桁架结构系统可靠度的敏度分析表达式。算例表明本文导出的敏度分析表达式是正确而有效的。从而使高效率地进行基于可靠性的结构优化设计成为可能。     

结构系统失效概率的近似分析

提出用一阶简单边界的上、下界来估计结构系统失效概率的近似公式。它考虑了结构系统失效模式之间的相关性但仅包含失效模式的一阶概率。算例表明,通常最大误差在5％以内,精度高而计算简便。     

Preliminary observing achievements of supersoft X-ray detector and γ-ray detector onboard Shenzhou2

Preliminary observing achievements by the Super Soft X-ray Detector and the γ-ray Detector in the fields of cosmic gamma-ray bursts, solar X-ray, bursts and cosmic X-ray/γ-ray background radiation are summarized. The detectors are aboard the spacecraft Shenzhou-2 that was launched on 2001 January 10. The scientific mission and general situation of the instruments are briefly described.     

RAMAN SPECTRA OF SEVEN INTERPLANETARY DUST PARTICLES

The Raman Shift Spectra of seven interplanetary dust particles,U2034 (F10),U2034(F8),U2022(B1),W7074 18,W7074 C15,W7074 C3 and W7074 A7,were measured with a Spex-1403 Raman Spectrograph.The exciting radiations were the 488 nm and 514 nm line of a 5W argon ion laser.All seven spectra exhibit the 1350 and 1600 Acm-1 arbon bands,implying that the IDPS were coated with hydrocarbon and incompletely crystallized carbon,the part of which may be the residue of hydro-carbon contents in the particles after water loss by the heating during their entry into the earth's atmosphere.A weak band structure in the 520-610 cm-1 range could be caused by cyclosilicates,and a weak band at 2900 cm-1 is tentatively identified as due to hydrocarbon molicules.