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801.
O. M. Alifanov S. A. Budnik A. V. Nenarokomov D. M. Titov 《Russian Aeronautics (Iz VUZ)》2016,59(4):548-553
This paper is devoted to the development of heat transfer models that are adequate to the real processes by using the experimental and computational methodology based on the theory of inverse heat transfer problems. 相似文献
802.
S. Dell’Agnello G.O. Delle Monache D.G. Currie R. Vittori C. Cantone M. Garattini A. Boni M. Martini C. Lops N. Intaglietta R. Tauraso D.A. Arnold M.R. Pearlman G. Bianco S. Zerbini M. Maiello S. Berardi L. Porcelli C.O. Alley J.F. McGarry C. Sciarretta V. Luceri T.W. Zagwodzki 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
We built a new experimental apparatus (the “Satellite/lunar laser ranging Characterization Facility”, SCF) and created a new test procedure (the SCF-Test) to characterize and model the detailed thermal behavior and the optical performance of cube corner laser retroreflectors in space for industrial and scientific applications. The primary goal of these innovative tools is to provide critical design and diagnostic capabilities for Satellites Laser Ranging (SLR) to Galileo and other GNSS (Global Navigation Satellite System) constellations. The capability will allow us to optimize the design of GNSS laser retroreflector payloads to maximize ranging efficiency, to improve signal-to-noise conditions in daylight and to provide pre-launch validation of retroreflector performance under laboratory-simulated space conditions. Implementation of new retroreflector designs being studied will help to improve GNSS orbits, which will then increase the accuracy, stability, and distribution of the International Terrestrial Reference Frame (ITRF), to provide better definition of the geocenter (origin) and the scale (length unit). 相似文献
803.
In September 1995, NASA-Goddard held a workshop on low-cost access to space for science missions. The workshop provided briefings on balloons, sounding rockets, Shuttle payloads, and low-cost free-flyer concepts, to provide options of getting experiments into space. This report is the result of a panel session organized with the aim of generating new ideas beyond those presented in the workshop. In addition to the authors, Orlando Figueroa and Paul Ondrus of NASA-Goddard and Richard Zwirnbaum of Computer Sciences Corp. participated in the discussions. The ideas presented do not necessarily reflect the current thinking of NASA managers. Although the panel discussion was focused on the kinds of science missions usually funded by NASA, most of the ideas that were generated are relevant to military and commercial missions as well. 相似文献
804.
Hsuan Ren Qian Du Jing Wang Chein-I Chang Jensen J.O. Jensen J.L. 《IEEE transactions on aerospace and electronic systems》2006,42(4):1372-1385
Due to recent advances in hyperspectral imaging sensors many subtle unknown signal sources that cannot be resolved by multispectral sensors can be now uncovered for target detection, discrimination, and identification. Because the information about such sources is generally not available, automatic target recognition (ATR) presents a great challenge to hyperspectral image analysts. Many approaches developed for ATR are based on second-order statistics in the past years. This paper investigates ATR techniques using high order statistics. For ATR in hyperspectral imagery, most interesting targets usually occur with low probabilities and small population and they generally cannot be described by second-order statistics. Under such circumstances, using high-order statistics to perform target detection have been shown by experiments in this paper to be more effective than using second order statistics. In order to further address a challenging issue in determining the number of signal sources needed to be detected, a recently developed concept of virtual dimensionality (VD) is used to estimate this number. The experiments demonstrate that using high-order statistics-based techniques in conjunction with the VD to perform ATR are indeed very effective 相似文献
805.
The behavior of small-scale irregularities of the electron density, which can exist in the near-Earth plasma at the ionospheric and magnetospheric heights is studied. They can be of both natural and artificial origin. The kinetic approach is used, and the Vlasov-Poisson system of equations is numerically solved using the method of large particles. In the plane perpendicular to the magnetic field, the evolution of a single irregularity having a circular cross-section at the initial moment is calculated. The influence of the transverse dimension of the irregularity and the value of deviation from electro-neutrality at the initial moment on the parameters characterizing the process of irregularity evolution is studied. 相似文献
806.
The combination of microelectronic acceleration transducers and an RF telemetry link can provide a reliable means of measuring shaft vibrations of electric drives. Clear advantages include the possibility of installing the instrumentation into currently existing motor systems without any need to use flexible couplings or mounts. The proposed system covers frequencies up to several kilohertz and can handle torque transients of 20 Nm with a typical uncertainty of 1%. The preliminary system is extendable to cover adaptive control of dynamic drive performance and can be customized to specific speed and torque ranges 相似文献
807.
O P Berezovska N V Rodionova E N Grigoryan V I Mitashov 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1998,21(8-9):1059-1063
Intensity of osteoclastic resorption and calcium content were investigated in intact limb bones of the newts flown on board of a biosatellite Cosmos-2229 after amputation of their forelimbs and tail. Using X-ray microanalysis it was shown an increase in calcium content in the bones on 20th day after operation. Histological study revealed an activation of osteoclastic resorption on endosteal surface of long bones. The newts exposed after surgery on a biosatellite had the same level of bone mineralisation as operated ground control ones, but the increase in number of polynuclear osteoclasts was lower. 相似文献
808.
809.
Becker R.H. Clayton R.N. Galimov E.M. Lammer H. Marty B. Pepin R.O. Wieler R. 《Space Science Reviews》2003,106(1-4):377-410
Variations in the isotopic ratios of volatile elements in different reservoirs on the terrestrial planets carry information
about processes that operated on the planets since their formation. Comparisons between primordial planetary compositions,
to the extent they can be determined, may help us understand the planetary formation process. This working group report summarizes
our knowledge of terrestrial planet volatile inventories.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
810.
O A Kuznetsov K H Hasenstein 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2001,27(5):887-892
The statoliths in Chara rhizoids are denser and more diamagnetic than the cytoplasm, therefore they can be displaced inside a living cell by a sufficiently strong high gradient magnetic field (HGMF). An experimental setup for intracellular magnetophoresis of statoliths was developed. The movement of statoliths and rhizoid growth was measured by video microscopy either under the influence of gravity or a HGMF equivalent to about 2 g. The contribution of the cytoskeleton to statolith motility was assayed before and after depolymerizing microtubules with oryzalin and F-actin with latrunculin B. Application of latrunculin caused immediate cessation of growth, clumping of statoliths, and application of HGMF resulted in higher displacement of statoliths. Oryzalin had no effect on the behavior of statoliths. The data indicate that magnetophoresis is a useful tool to study the gravisensing system and rheology of the Chara rhizoid. 相似文献