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81.
Small scale structure in local interstellar matter (LISM) is considered. Overall morphology of the local cloud complex is inferred from Ca II absorption lines and observations of H I in white dwarf stars. Clouds with column densities ranging from 2–100 × 1017 cm–2 are found within 20 pc of the Sun. Cold (50 K) dense (105 cm–3) small (5–10 au) clouds could be embedded and currently undetected in the upwind gas. The Sun appears to be embedded in a filament of gas with thickness 0.7 pc, and cross-wise column density 2 × 1017 cm–2. The local magnetic field direction is parallel to the filament, suggesting that the physical process causing the filamentation is MHD related. Enhanced abundances of refractory elements and LISM kinematics indicate outflowing gas from the Scorpius-Centaurus Association. The local flow vector and Sco data are consistent with a 4,000,000 year old superbubble shell at –22 km s–1, which is a shock front passing through preshock gas at –12 km s–1, and yielding cooled postshock gas at –26 km s–1in the upwind direction. A preshock magnetic field strength of 1.6 G, and postshock field strength of 5.2 G embedded in the superbubble shell, are consistent with the data.Abbreviations LISM Local ISM - SIC Surrounding Interstellar Cloud - LIC Local Interstellar Cloud  相似文献   
82.
We use energy spectra of anomalous cosmic rays (ACRs) measured with the Cosmic Ray instrument on the Voyager 1 and 2 spacecraft during the period 1994/157-313 to determine several parameters of interest to heliospheric studies. We estimate that the strength of the solar wind termination shock is 2.42 (–0.08, +0.04). We determine the composition of ACRs by estimating their differential energy spectra at the shock and find the following abundance ratios: H/He = 5.6 (–0.5, +0.6), C/He = 0.00048 ± 0.00011, N/He = 0.011 ± 0.001, O/He = 0.075 ± 0.006, and Ne/He = 0.0050 ± 0.0004. We correlate our observations with those of pickup ions to deduce that the long-term ionization rate of neutral nitrogen at 1 AU is 8.3 × 10–7 s–1 and that the charge-exchange cross section for neutral N and solar wind protons is 1.0 × 10–15 cm2 at 1.1 keV. We estimate that the neutral C/He ratio in the outer heliosphere is 1.8(–0.7, +0.9) × 10–5. We also find that heavy ions are preferentially injected into the acceleration process at the termination shock.  相似文献   
83.
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。  相似文献   
84.
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.  相似文献   
85.
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。  相似文献   
86.
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。  相似文献   
87.
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。  相似文献   
88.
冲压发动机超薄壁波纹形件的粘性介质压力成形   总被引:1,自引:1,他引:1       下载免费PDF全文
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。  相似文献   
89.
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.  相似文献   

90.
Time-dependent kinetic-continuum model of the solar wind interaction with the two-component local interstellar cloud (LIC) has been developed recently [Izmodenov, V., Malama, Y.G., Ruderman, M.S. Solar cycle influence on the interaction of the solar wind with local interstellar cloud. Astron. Astrophys. 429, 1069–1080, 2005a.]. Here, we adopted this model to the realistic solar cycle, when the solar wind parameters at the Earth’s orbit are taken from space data. This paper focuses on the results related to the termination shock (TS) excursion with the solar cycle that may help to understand Voyager 1 data obtained at and after the crossing of the termination shock and to predict the time of the TS crossing by Voyager 2.  相似文献   
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