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91.
依据差压铸造浇注工作原理,确定差压铸造浇注的工艺参数,结合舱体铸件壁厚差较大;结构复杂等特性,设计砂型铸造工艺方案,成功地生产了ZL205A舱体铸件。铸件经X光、荧光检测,内部、表面质量符合HB963-2005 I类之要求。 相似文献
92.
为了研究空间微小碎片碰撞对航天器的影响,国内外研制了各种类型的微小碎片加速器。文章简要介绍了一种很有前景的静电式微小碎片加速器及其关键部件的工作原理、结构特点及适用范围等。 相似文献
93.
The chemical composition of comet nuclei derived from current data on interstellar dust ingredients and comet dust and coma
molecules are shown to be substantially consistent with each other in both refractory and volatile components. When limited
by relative cosmic abundances the water in comet nuclei is constrained to be close to 30% by mass and the refractory to volatile
ratio is close to 1:1. The morphological structure of comet nuclei, as deduced from comet dust infrared continuum and spectral
emission properties, is described by a fluffy (porous) aggregate of tenth micron silicate core-organic refractory mantle particle
on which outer mantles of predominantly H2O ices contain embedded carbonaceous and polycyclic aromatic hydrocarbon (PAH) type particles of size in the of 1 - 10nm range.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
94.
在解析日本铁矿石资源现状的基础上,进一步梳理了日本铁矿石战略模式,将其总结为两个基础(获得海外权益矿、铁矿石战略储备制度)、四个保障(政府支持、法律保障、海运配套及技术支持)和多方互动;并指出对我国铁矿石战略的五大借鉴意义。 相似文献
95.
ISO performed a large variety of observing programmes on comets, asteroids and zodiacal light – covering about 1% of the archived
observations – with a surprisingly rewarding scientific return. Outstanding results were related to the exceptionally bright
comet Hale–Bopp and to ISO's capability to study in detail the water spectrum in a direct way. But many other results were
broadly recognised: Discovery of new molecules in comets, the studies of crystalline silicates, the work on asteroid surface
mineralogy, results from thermophysical studies of asteroids, a new determination of the asteroid number density in the main-belt
and last but not least, the investigations on the spatial and spectral features of the zodiacal light. 相似文献
96.
Harald Krüger Markus Landgraf Nicolas Altobelli Eberhard Grün 《Space Science Reviews》2007,130(1-4):401-408
The Ulysses spacecraft has been orbiting the Sun on a highly inclined ellipse almost perpendicular to the ecliptic plane (inclination
79°, perihelion distance 1.3 AU, aphelion distance 5.4 AU) since it encountered Jupiter in 1992. The in situ dust detector
on board continuously measured interstellar dust grains with masses up to 10−13 kg, penetrating deep into the solar system. The flow direction is close to the mean apex of the Sun’s motion through the
solar system and the grains act as tracers of the physical conditions in the local interstellar cloud (LIC). While Ulysses
monitored the interstellar dust stream at high ecliptic latitudes between 3 and 5 AU, interstellar impactors were also measured
with the in situ dust detectors on board Cassini, Galileo and Helios, covering a heliocentric distance range between 0.3 and
3 AU in the ecliptic plane. The interstellar dust stream in the inner solar system is altered by the solar radiation pressure
force, gravitational focussing and interaction of charged grains with the time varying interplanetary magnetic field. We review
the results from in situ interstellar dust measurements in the solar system and present Ulysses’ latest interstellar dust
data. These data indicate a 30° shift in the impact direction of interstellar grains w.r.t. the interstellar helium flow direction,
the reason of which is presently unknown. 相似文献
97.
Johannes Mathies Steffen Mauceri Lukas Pfeiffer Marco Vietze Hans-Peter Roeser Felix BoehringerMichael Lengowski 《Acta Astronautica》2014
SSETO is the result of a phase-A study in context of the small satellite program of the University of Stuttgart that demonstrates the capability of a university institute to build a small satellite with a budget of 5 million Euro. The satellite will be capable of observing exoplanets in a Neptune–Earth scale and obtaining data of interstellar dust. Due to a system failure of NASA?s Kepler mission, there is currently (October 2013) a lack of satellites searching for exoplanets. This paper details the design of subsystems and payload, as well as the required test tasks in accordance with the mission profile at a conceptional level. The costs for standard spacecraft testing and integration tasks are included, but not those of launch, ground support, operations and engineer working hours. 相似文献
98.
熊辉 《南昌航空工业学院学报》1996,(2):75-78
本文针对我国目前一些小型锅炉烟尘除法装置存在的售价高、使用寿命短、除尘效率低等问题,介绍一种新型湿式陶瓷除尘器的设计与开发过程。该除尘器具有高效、价廉、无二次污染等特性,适用于小型锅炉的烟尘治理。 相似文献
99.
100.
S. Takechi T. Onishi S. Minami T. Miyachi M. Fujii N. Hasebe K. Mori K. Nogami H. Ohashi S. Sasaki H. Shibata T. Iwai E. Grün R. Srama N. Okada 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2009
A cosmic dust detector is currently being developed using a piezoelectric lead zirconate titanate (PZT) element. The characteristics of the multilayered detector (MD), which was composed of one hundred PZT disks, were investigated by bombarding it with hypervelocity iron particles supplied by a Van de Graaff accelerator. It was confirmed that there was a linear relationship between the signal amplitude observed from MD and the momentum of the particles. As compared with the single-layered detector (SD) that was composed of one PZT disk, it was found that the sensitivity of MD was ∼3 times higher than that of SD within the limits of the experimental conditions. 相似文献