飞机液压管路支撑的有限元建模方式对应力分析的影响

在飞机典型液压导管不同构型和负载模式下,做了应力试验测量,得到应力试验的数据,并在有限元环境MSC.PATRAN中,针对导管的不同构型建立有限元分析模型,对每种构型下支架与卡箍采用八种不同的简化方式,得到仿真结果。然后将不同简化方式的仿真结果与试验结果作对比分析,考虑不同因素(如支架刚度、卡箍橡胶刚度、导管与橡胶间的摩擦与滑动等)对分析结果的影响,找到了在工程上简单易行,精度上可以接受的支撑简化方法。     

Cutting the bread

Why the draft Treaty on the Prevention of the Placement of Weapons in Outer Space, the Threat or Use of Force Against Outer Space Objects (PPWT) will not work - whereas the Code of Conduct for Outer Space Activities may.     

Viewing radiation signatures of solar energetic particles in interplanetary space

A current serious limitation on the studies of solar energetic particle (SEP) events is that their properties in the inner heliosphere are studied only through in situ spacecraft observations. Our understanding of spatial distributions and temporal variations of SEP events has come through statistical studies of many such events over several solar cycles. In contrast, flare SEPs in the solar corona can be imaged through their radiative and collisional interactions with solar fields and particles. We suggest that the heliospheric SEPs may also interact with heliospheric particles and fields to produce signatures which can be remotely observed and imaged. A challenge with any such candidate signature is to separate it from that of flare SEPs. The optimum case for imaging high-energy (E > 100 MeV) heliospheric protons may be the emission of π⁰-decay γ-rays following proton collisions with solar wind (SW) ions. In the case of E > 1 MeV electrons, gyrosynchrotron radio emission may be the most readily detectible remote signal. In both cases we may already have observed one or two such events. Another radiative signature from nonthermal particles may be resonant transition radiation, which has likely already been observed from solar flare electrons. We discuss energetic neutrons as another possible remote signature, but we rule out γ-ray line and 0.511 MeV positron annihilation emission as observable signatures of heliospheric energetic ions. We are already acquiring global signatures of large inner-heliospheric SW density features and of heliosheath interactions between the SW and interstellar neutral ions. By finding an appropriate observable signature of remote heliospheric SEPs, we could supplement the in situ observations with global maps of energetic SEP events to provide a comprehensive view of SEP events.     

GaInP2外延膜中施主—受主对复合发光带的能量关量

通过变温与变激发强度的近红外光致发光研究了用ＭＯＣＶＤ方法、生长在ＧａＡｓ衬底上的Ｇａ０．５Ｉｎ０．５Ｐ（ＧａＩｎＰ２）外延薄膜的１．１７ｅＶ发射带的发光特性。１．１７ｅＶ发光带性质与０．９９ｅＶ及０．８５ｅＶ发光带的性质有着明显的差别。１．１７ｅＶ发光带的机理可用施主－受主对的复合发光来解释，其中施主－受主对系白处在Ｇａ格位上的Ｓｉ（ＳｉＧａ）及其最邻近的Ｇａ空位（ＶＧａ）所组成，记作ＳｉＧａ－ＶＧａ。考虑到ＧａＩｎＰ２中存在着很强的电子－格子耦合作用及其Ⅲ族子格子为部分有序，所以在施主－受主对复合发光中应计及Ｆｒａｎｃｋ－Ｃｏｎｄｏｎ位移△ＦＣ及该对在等效的部分有序势场中的相互作用能Ｅｓ（ＤＡＰ）。Ｘ—射线衍射实验表明，部分有序结构相当于成分调制，因而可用Ｋｒｏｎｉｇ－Ｐｅｎｎｅｙ模型来计算Ｅｓ（ＤＡＰ）值。这样，我们就导出了施主－受主对复合发光的新的能量表示式。     

The Seed Population for Energetic Particles Accelerated by CME-Driven Shocks

Understanding properties of solar energetic particle (SEP) events associated with coronal mass ejections has been identified as a key problem in solar-terrestrial physics. Although recent CME shock acceleration models are highly promising, detailed agreement between theoretical predictions and observations has remained elusive. Recent observations from ACE have shown substantial enrichments in the abundances of ³He and He⁺ ions which are extremely rare in the thermal solar wind plasma. Consequently, these ions act as tracers of their source material, i.e., ³He ions are flare suprathermals and He⁺ ions are interstellar pickup ions. The average heavy ion composition also exhibits unsystematic differences when compared with the solar wind values, but correlates significantly with the ambient suprathermal material abundances. Taken together these results provide compelling evidence that CME-driven shocks draw their source material from the ubiquitous but largely unexplored suprathermal tail rather than from the more abundant solar wind peak. However, the suprathermal energy regime has many more contributors and exhibits much larger variability than the solar wind, and as such needs to be investigated more thoroughly. Answers to fundamental new questions regarding the preferred injection of the suprathermal ions, the spatial and temporal dependence of the various sources, and the causes of their variability and their effects on the SEP properties are needed to improve agreement between the simulations and observations.     

Energetic Hydrogen and Oxygen Atoms Observed on the Nightside of Mars

We present measurements of energetic hydrogen and oxygen atoms (ENAs) on the nightside of Mars detected by the neutral particle detector (NPD) of ASPERA-3 on Mars Express. We focus on the observations for which the field-of-view of NPD was directed at the nightside of Mars or at the region around the limb, thus monitoring the flow of ENAs towards the nightside of the planet. We derive energy spectra and total fluxes, and have compiled maps of hydrogen ENA outflow. The hydrogen ENA intensities reach 10⁵ cm⁻² sr⁻¹ s⁻¹, but no oxygen ENA signals above the detection threshold of 10⁴ cm⁻² sr⁻¹ s⁻¹ are observed. These intensities are considerably lower than most theoretical predictions. We explain the discrepancy as due to an overestimation of the charge-exchange processes in the models for which too high an exospheric density was assumed. Recent UV limb emission measurements (Galli et al., this issue) point to a hydrogen exobase density of 10¹⁰ m⁻³ and a very hot hydrogen component, whereas the models were based on a hydrogen exobase density of 10¹² m⁻³ and a temperature of 200 K predicted by Krasnopolsky and Gladstone (1996). Finally, we estimate the global atmospheric loss rate of hydrogen and oxygen due to the production of ENAs.     

缔约过失责任问题探讨

缔约过失责任是在合同缔结过程中产生的一种责任形式，是合同法中一项独立的法律制度。缔约过失责任与违约责任有着本质的区别，是基于缔约方违反先合同义务产生的责任形式，其损害对象是对方的信赖利益，而不是合同利益。本文通过对缔约过失责任的论述，阐明其产生的理论基础、成立要件、责任形式以及立法现状和趋势，谨希望能有助于我国相关立法的发展与完善。     

分光计调节环节的补充及其应用

分光计是各高等院校在大学物理实验课教学中常用的一种仪器装置。分光计的调节对大学生基本实验技能的训练和培养有着十分重要的作用。本人在大学物理实验课全面开放式教学中,通过《分光计的使用》实验项目的教学实践、探索,提出了对分光计调节环节的补充建议,不仅使分光计调节环节的要求更加严谨,而且在实践教学的学生实验成绩评定考核方面,以及在实验指导教师对实验仪器装置精密度的检测方面都具有十分现实的应用意义。     

谈若干特殊结构的汉译

翻译是英语教学中的一个重要方面，是英语水平评价的一个重要标准。如何提高翻译水平是一个重要课题。英语中一些由小词开头的特殊结构，如for that matter，if ever，if at all…等，用法特殊，词义不易捉摸，汉语中也难找到相应的结构来表达的。在此文中用等值原则和灵活性原则探讨了这些特殊结构的含义及其用法。     

探析新《道路交通安全法》中法律归责原则及完善问题

2004年5月1日开始实施的《中华人民共和国道路交通安全法》针对机动车与机动车之间、机动车与非机动车驾驶人或行人之间的交通事故，分别确立了过错责任和无过错责任两种不同的归责原则。本文拟运用侵权行为法归责原则理论，通过国内外有关法律之比较分析及我国新旧交通安全法规对道路交通事故责任承担问题展开讨论，以求抛砖引玉。