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891.
K.S. Rao P. Venkatachalam A. Sowmya A.K. Kandya T.J. Majumdar 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1984,4(11):91-96
With the objective of developing Microwave Remote Sensing technology in the country, India has launched a series of Satellites Bhaskara-I and II with the microwave radiometer capability. In this paper, an attempt is made to demonstrate the capability of the brightness temperature data acquired by these radiometers to discriminate various soil moisture conditions of Indian land mass. The analysis show that large areas assessment of soil moisture is possible to a limited extent. 相似文献
892.
E. Grün G.W. Garneau R.J. Terrile T.V. Johnson G.E. Morfill 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1984,4(9):143-148
Voyager 2 images of Saturn's rings have been analyzed for spoke activity. More than 80 and 40 different spokes have been measured at the morning and at the evening ansa, respectively. Higher rate of spoke formation has been found at 145° ± 15° SLS and at 305° ± 15° SLS which persisted for at least 3 Saturn revolutions. Higher spoke activity (formation and growth in width) by more than a factor 3 has been observed over the nightside hemisphere of Saturn than over the dayside hemisphere. The age distribution (i.e. time from radial formation until observation, assuming Keplerian shear) of the leading (old) edges of spokes has its maximum at ~ 9,000 s and ~ 6,000 s for spokes observed at the morning ansa and at the evening ansa, respectively. The highest spoke age observed is ~ 20,000 s. The age distribution of the trailing (young) edges of spokes peaks at < 2,000 s at both ansae but has its mean at ~ 4,500 s and ~ 3,500 s, respectively. On the average the observed spokes grew in width for ~ 4,500 s at the morning ansa and for ~ 2,500 s at the evening ansa. The maximum time of growth in width was ~ 12,000 s. 相似文献
893.
In-orbit demonstration of rendezvous laser radar for unmanned autonomous rendezvous docking 总被引:1,自引:0,他引:1
Mokuno M. Kawano I. Suzuki T. 《IEEE transactions on aerospace and electronic systems》2004,40(2):617-626
The National Space Development Agency of Japan (NASDA) performed unmanned autonomous rendezvous docking (RVD) experiments using the Engineering Test Satellite VII (ETS-VII) in 1998 and 1999. In these experiments, a rendezvous laser radar (RVR) was used as the primary navigation sensor during the final approach phase (relative distances from 500 m to 2 m). The RVR functioned properly, and its characteristics, which are measurement accuracy, optical propagation, and acquisition/tracking, satisfied the requirements. The experimental results show that RVR is effective for autonomous rendezvous docking. 相似文献
894.
T. Belloni 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2006,38(12):2801-2804
Due to the impressive amount of new data provided by the RXTE satellite in the past decade, our knowledge of the phenomenology of accretion onto black holes has increased considerably. In particular, it has been possible to schematize the outburst evolution of transient systems on the basis of their spectral and timing properties, and link them to the ejection of relativistic jets as observed in the radio. Here, I present this scheme, concentrating on the properties of the quasi-periodic oscillations observed in the light curves and on the link with jet ejection. 相似文献
895.
T.S.Burns 《世界航空航天博览》2006,(11):78-81
几乎所有管理海军的军人,都没有成功地进行重大工程研制所需要的经验,也没有操管采用现代技术的复杂设备方面的训练经验。现在海军的情况是,军官有三个组成部分,他们是飞行军官、水面舰艇军官和潜艇军官。飞行军官的影响最大,其次是水面舰艇军官,最后才是潜艇军官。这主要是因为潜艇军官的人数太少。——美国海军上将海曼&;#183;里科弗 相似文献
896.
Two types of battery-powered, compact, ground probing radar (GPR) systems have been developed. The systems have CRT displays mounted on antenna units and are used to locate such underground objects as gas pipes, water pipes, and transmission cables. The performance of the systems and results of field tests are reported. The GPR detected 59 of 64 underground gas pipes; a 200-mm-diameter pipe is clearly detected at a depth of 2.3 m 相似文献
897.
M. Alexander P. Anz T. Hyde A. Hargrave W. Tanner L. Lodhi S. Lodhi 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1984,4(9):27-30
Extensive studies have been conducted concerning individual mass, temporal and positional distribution of submicron rocky ejecta existing in the satellite-planetary gravitational sphere of influence. The transit time of the major portion of the ejecta that is transported from the satellite's gravitational sphere of influence to the planetary magnetopause is about one week and represents a mass loading pulse occurring each satellite orbit. The mass-flux distributions of lunar ejecta at the surface of the magnetopause for a complete lunar orbit are presented. Spatial mass densities of lunar ejecta in specific zones of the magnetosphere provide a means to compare sporadic interplanetary dust spatial mass densities in the same zones. 相似文献
898.
L T Mishchenko A M Silayeva I A Mishchenko A L Boyko 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2004,34(7):1607-1611
The effects of clinostating on physiological processes and biochemical characteristics of wheat plants (Triticum aestivum L.) both healthy and infected by the wheat streak mosaic virus (WSMV) were studied. In six experiments, each lasting over 30 days, healthy and infected plants of the dwarf Apogee variety were grown under conditions of continuous horizontal and vertical clinostating with 2 rpm at 21 +/- 2 degrees C and 6000 1x (the optimal moisture of a substrate being maintained). The control variants (healthy and infected) were simultaneously grown under the same conditions of temperature and illumination in stationary containers and in open pots. During the experiment, visual observations were carried out over the state of tested plants. After completing the experiment, biometric indices, pigment, carbohydrate and dry matter contents were determined in all the plants. It was shown that clinostating sharply reduced the reproductive function of healthy plants and considerably affected their biomass (productivity) and concentration of chlorophylls and sugars. The viral infection resulted in further reduction of these characteristics. In control variants the viral effect was more significant. We speculate that clinostating reduced the rate of reproduction and spread of the virus. 相似文献
899.
R T Reynolds C P McKay J F Kasting 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1987,7(5):125-132
Tidal dissipation in the satellites of a giant planet may provide sufficient heating to maintain an environment favorable to life on the satellite surface or just below a thin ice layer. In our own solar system, Europa, one of the Galilean satellites of Jupiter, could have a liquid ocean which may occasionally receive sunlight through cracks in the overlying ice shell. In such case, sufficient solar energy could reach liquid water that organisms similar to those found under Antarctic ice could grow. In other solar systems, larger satellites with more significant heat flow could represent environments that are stable over an order of Aeons and in which life could perhaps evolve. We define a zone around a giant planet in which such satellites could exist as a tidally-heated habitable zone. This zone can be compared to the habitable zone which results from heating due to the radiation of a central star. In our solar system, this radiatively-heated habitable zone contains the Earth. 相似文献
900.
Sidhwa F. Moore F. Williams T. Matsuura D. 《Aerospace and Electronic Systems Magazine, IEEE》2004,19(7):31-36
In today's world of constrained budgets, one of the problems the military faces is the challenge of trying to maintain organic maintenance capabilities. Historically, the US Air Force has desired to achieve an autonomous capability to maintain the equipment it uses. This has been achieved, traditionally, by setting-up three levels of maintenance: organizational; intermediate (back-shop); and depot. The I-level back-shops often utilize militarized automatic test equipment (ATE) and test program sets (TPSs) to test today's complex aircraft line replaceable units (LRUs). And even though this is still a cost-effective maintenance philosophy, it has become costly to develop militarized ATE. The Department of Defense (DoD) has been very active in trying to reduce the total ownership cost of ATE in the government inventory. One approach is to utilize commercial, instead of Mil-Spec, ATE. However, utilizing commercial ATE at an USAF back-shop is not without its tradeoffs and challenges as it represents a significant deviation from the way the USAF maintenance squadrons are accustomed to "doing business." This paper documents the current success story of replacing the legacy C-17 I-level ATE with a commercial ATE. 相似文献