飞机全,静压系统除水研究

阐述了全，静压系统中水的形成及其在导管中运动的方式，以及水柱移动的稳定位置与仪表的水柱误差指示值；提出了沉淀器的安装和管路的敷设要求。     

药柱裂纹对固体火箭发动机工作过程的影响

针对某固体火箭发动机点火启动时所受的燃气载荷,用线性粘弹性有限元法分析了无缺陷药柱和含有裂纹药柱的应力—应变场,并探讨了单裂纹部位、裂纹尺寸对发动机工作安全性的影响以及多裂纹条件下,裂纹尺寸和相互位置对裂纹扩展的影响。所得到的结论对制定固体发动机失效判据有一定的参考价值。     

Deuterium Abundance in the Local ISM and Possible Spatial Variations

Excellent HST/GHRS spectra of interstellar hydrogen and deuterium Lyman- absorption toward nearby stars allow us to identify systematic errors that have plagued earlier work and to measure accurate values of the D/H ratio in local interstellar gas. Analysis of 12 sightlines through the Local Interstellar Cloud leads to a mean value of D/H = (1.50 ± 0.10) × 10-5 with all data points lying within ± 1 of the mean. Whether or not the D/H ratio has different values elsewhere in the Galaxy and beyond is a very important open question that will be one of the major objectives of the Far Ultraviolet Spectroscopic Explorer (FUSE) mission.     

压力传感器膜片表面温度的测量和分析计算

用红外热成象技术测量应变式压力传感器工作时的膜片温度分布,以判断由于电阻应变片工作时温度变化对测量准确性的影响。测量中为获得应变片的真实温度,作了表面喷黑处理。对于实用的3MPa和0.6MPa的压力传感器,在不同工作介质(空气和变压器油)及工作电压条件下进行了测量,其结果表明:应变片表面温度随工作电压增高而加大,且不均匀。以空气为介质的温度高于以变压器油为介质的温度。据此可以确定对压力测量准确度的影响。还用有限差分方法对压力传感器膜片表面温度作了数值分析计算。     

谈国有大中型企业法律顾问的作用

加入WTO后，在权利与义务对等的基础上，中国承诺将严格执行世贸组织的规章制度。这需要我国的经济管理与国际经济活动的游规则接轨，也必然要求强化律师在企业中的法律顾问作用。其作用如何发挥，律师怎样介入，作者对此进行了探讨。     

电子档案的特征及管理对策分析

在电子网络时代里，档案工作者正迎接着电子文件的挑战。把电子文件及其归档后形成的电子档案管理好并利用好，是档案工作者义不容辞的责任。论述了电子文件载体寿命与技术寿命的特点以及影响其寿命的因素，提出了收集、管理与利用电子文件的具体对策与措施。     

冲压发动机超薄壁波纹形件的粘性介质压力成形

粘性介质压力成形是一种采用具有高粘度并且可流动的半固态介质作为软凸模的成形方法。采用试验和数值模拟方法，研究了高温合金超薄壁波纹形件成形过程坯料形状、应变分布、厚度分布的变化和界面摩擦对板料成形的影响，研究结果表明：成形件尺寸精度高、表面质量好、厚度均匀；与钢凸模成形相比较，可以避免局部较小半径曲面之间的严重颈缩；对于具有局部较小半径曲面的复杂形状薄壁件，粘性介质压力成形显示出其优越性。     

The interstellar heliopause probe technology reference study

The interstellar heliopause probe (IHP) is one of ESA’s technology reference studies (TRS). The TRS aim to focus the development of strategically important technologies of relevance to future science missions by studying technologically demanding and scientifically interesting missions that are currently not part of the science mission programme.

Equipped with a highly integrated payload suite (HIPS), the IHP will perform in situ exploration of the heliopause and the heliospheric interface. The HIPS, which is a standard element in all TRSs, miniaturize payloads through resource reduction by using miniaturized components and sensors, and by sharing common structures and payload functionality.

To achieve the scientific requirements of the mission, the spacecraft is to leave the heliosphere as close to the heliosphere nose as possible and reach a distance of 200 AU from the Sun within 25 years. This is possible by using a trajectory with two solar flybys and a solar sail with characteristic acceleration of 1.1 mm/s², which corresponds to a 245 × 245 m² solar sail and a sail thickness of 1–2 μm. The trajectory facilitates a modest sail design that could potentially be developed in a reasonable timeframe.

In this paper, an update to the results of studies being performed on this mission will be given and the current mission baseline and spacecraft design will be described. Furthermore, alternative solar sail systems and enabling technologies will be discussed.     

Numerical Simulations of the Warm-Hot Intergalactic Medium

In this paper we review the current predictions of numerical simulations for the origin and observability of the warm hot intergalactic medium (WHIM), the diffuse gas that contains up to 50 per cent of the baryons at z∼0. During structure formation, gravitational accretion shocks emerging from collapsing regions gradually heat the intergalactic medium (IGM) to temperatures in the range T∼10⁵–10⁷ K. The WHIM is predicted to radiate most of its energy in the ultraviolet (UV) and X-ray bands and to contribute a significant fraction of the soft X-ray background emission. While O vi and C iv absorption systems arising in the cooler fraction of the WHIM with T∼10⁵–10^5.5 K are seen in FUSE and Hubble Space Telescope observations, models agree that current X-ray telescopes such as Chandra and XMM-Newton do not have enough sensitivity to detect the hotter WHIM. However, future missions such as Constellation-X and XEUS might be able to detect both emission lines and absorption systems from highly ionised atoms such as O vii, O viii and Fe xvii.     

Equilibration Processes in the Warm-Hot Intergalactic Medium

The Warm-Hot Intergalactic Medium (WHIM) is thought to contribute about 40–50% to the baryonic budget at the present evolution stage of the universe. The observed large scale structure is likely to be due to gravitational growth of density fluctuations in the post-inflation era. The evolving cosmic web is governed by non-linear gravitational growth of the initially weak density fluctuations in the dark energy dominated cosmology. Non-linear structure formation, accretion and merging processes, star forming and AGN activity produce gas shocks in the WHIM. Shock waves are converting a fraction of the gravitation power to thermal and non-thermal emission of baryonic/leptonic matter. They provide the most likely way to power the luminous matter in the WHIM. The plasma shocks in the WHIM are expected to be collisionless. Collisionless shocks produce a highly non-equilibrium state with anisotropic temperatures and a large differences in ion and electron temperatures. We discuss the ion and electron heating by the collisionless shocks and then review the plasma processes responsible for the Coulomb equilibration and collisional ionisation equilibrium of oxygen ions in the WHIM. MHD-turbulence produced by the strong collisionless shocks could provide a sizeable non-thermal contribution to the observed Doppler parameter of the UV line spectra of the WHIM.