连接器支架结构优化设计分析

某型连接器支架普遍出现断裂现象,经判断原因是动强度设计不合理,在振动载荷作用下发生疲劳破坏,为了确保支架不出现结构损伤,保证飞行安全,需要进行结构优化设计分析。基于克希霍夫理论,采用有限元分析手段,通过改变厚度、材料与结构形式的方法,对支架进行模态分析与随机响应分析,最终得到了在满足动强度设计要求的情况下质量最轻的支架。根据分析结果总结了一种结构优化设计分析的流程:先改结构形式,用相对系数判断优劣;再选疲劳性能好的材料;最后选择合适的厚度。该流程在本文中得到有效实施,可在今后用于相似结构的优化设计分析。     

The Cool Interstellar Medium

Infrared spectroscopy and photometry with ISO covering most of the emission range of the interstellar medium has led to important progress in the understanding of the physics and chemistry of the gas, the nature and evolution of the dust grains and also the coupling between the gas and the grains. We review here the ISO results on the cool and low-excitation regions of the interstellar medium, where T _gas≲ 500 K, n _H∼ 100–10⁵ cm⁻³ and the electron density is a few 10⁻⁴. JEL codes: D24, L60, 047 Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, The Netherlands, and the United Kingdom), and with the participation of ISAS and NASA.     

非齐次Poisson过程的若干新性质

本文在一些文献的基础上,进一步讨论非齐次Poisson过程的某些性质,给出了若干新性质。 设{N(t),t≥0}是累积强度为的非齐次Poisson过程。迄今的文献(如[1][2]等)指出,(?)n≥1,前n个到达时刻τ_1,τ_2,…,τ_n的联合概率密度为 本文定理1指出,上式不仅是必要的,而且是充分的,并给出了充分性的证明。从而,得到了描写过程统计规律的一个刻画。然后,在N(t_i)=n_i(i=1,…,k,0相似文献   

结构随机跳变系统的条件滤波新方法

提出了不完全状态及控制信息的结构随机跳变系统的滤波方法，解决了结构随机跳变系统在控制入与状态的观测互为相关情况下，系统的状态以及不确知的控制输入的最优估计问题。并以线性高斯情况为例进行了数字仿真，证明了该方法的有效性。     

Nuclear fragmentation database for GCR transport code development

A critical need for NASA is the ability to accurately model the transport of heavy ions in the Galactic Cosmic Rays (GCR) through matter, including spacecraft walls, equipment racks, etc. Nuclear interactions are of great importance in the GCR transport problem, as they can cause fragmentation of the incoming ion into lighter ions. Since the radiation dose delivered by a particle is proportional to the square of (charge/velocity), fragmentation reduces the dose delivered by incident ions. The other mechanism by which dose can be reduced is ionization energy loss, which can lead to some particles stopping in the shielding. This is the conventional notion of shielding, but it is not applicable to human spaceflight since the particles in the GCR tend to be too energetic to be stopped in the relatively thin shielding that is possible within payload mass constraints. Our group has measured a large number of fragmentation cross sections, intended to be used as input to, or for validation of, NASA’s radiation transport models. A database containing over 200 charge-changing cross sections and over 2000 fragment production cross sections has been compiled. In this report, we examine in detail the contrast between fragment measurements at large acceptance and small acceptance. We use output from the PHITS Monte Carlo code to test our assumptions using as an example ⁴⁰Ar data (and simulated data) at a beam energy of 650 MeV/nucleon. We also present preliminary analysis in which isotopic resolution was attained for beryllium fragments produced by beams of ¹⁰B and ¹¹B. Future work on the experimental data set will focus on extracting and interpreting production cross sections for light fragments.     

Radial and latitudinal gradients of galactic cosmic rays in the heliosphere at solar maximum

Our understanding of galactic cosmic ray (GCR) modulation has advanced greatly in the last three decades. However, we still need an appropriate knowledge of the GCR intensity gradient. Numerical simulations of the transport particle equation allow interpretation of cosmic ray intensities in the heliosphere. We use the numerical solution of the GCR transport equation during solar maximum epoch to compute the radial and latitudinal gradients. Our analysis indicates that adiabatic energy loss plays an important role in the radial distribution of GCR in the inner heliosphere, while in the outer region the diffusion and convection are the relevant processes. The latitudinal gradient is small.     

Stark broadening of B IV lines for astrophysical and laboratory plasma research

Stark broadening parameters for 36 multiplets of B IV have been calculated using the semi-classical perturbation formalism. Obtained results have been used to investigate the regularities within spectral series and temperature dependence.     

Stark widths of Ar III spectral lines in the atmospheres of subdwarf B stars

Using semiclassical perturbation approach in impact approximation, we have calculated Stark widths for 32 spectral lines of doubly charged argon (Ar III). Oscillator strengths are calculated using Hartree–Fock method with relativistic correction (HFR) and an atomic model including 17 configurations. Energy levels are taken from NIST database. For perturbing levels for which the corresponding energy does not exist in NIST database, the calculated energies are used. Our widths are compared with the experimental results. The results presented here are of interest for modelling and investigation of stellar atmospheres since argon in different ionization stages is observed in many astrophysical objects. Finally, the importance of Stark broadening mechanism is studied in the atmospheric conditions of sdB stars. Electron impact Stark widths are compared to thermal Doppler widths as a function of temperature and optical depth of atmospheric layers.     

高阶矩谱分析与空间等离子体非线性相互作用识别

利用高阶矩统计分析方法对ＡＵＲＥＯＬ－３卫星观测数据进行分析处理，所涉及的信号分别为ＥＬＦ频率范围内的电场扰动Ｅｈ（ｔ）和等离子体密度波动δＮｅ／ｎｅ（ｔ），处理结果表明：利用高阶矩谱分析方法可以很好地识别空间等离了波－粒相互作用过程中的非线性成分     

非金属电热膜材料及工艺分析

本文论述了制作电热膜的工艺过程.对电热膜的材料、烧结工艺及使用寿命进行了试验,获得了有价值的结论.并论述了提高电热膜产品寿命应注意的问题.