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961.
Garmash V.R. Katsenelenbaum B.Z. Shaposhnikov S.S. Tioulpakov V.N. Vaganov R.B. 《Aerospace and Electronic Systems Magazine, IEEE》1998,13(10):39-41
Some wave beam peculiarities which usually are wasted are useful in wireless power transmission systems. These peculiarities-the focusing of the beam, the taper distribution of the radiating field, and the discontinuous antenna-are discussed 相似文献
962.
U. Geppert B. Biering F. Lura J. Block M. Straubel R. Reinhard 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
The 3-step Gossamer road map to solar sailing is presented that has been agreed between DLR and ESA in November 2009. The main and exclusive purpose of that project is to develop, to prove, and to demonstrate the solar sail technology as a safe and reliably manageable propulsion technique for long lasting and deep space missions. Since the development of the solar sail technology is quite a complex task, presently at the DLR implemented solar sail related research activities will be presented as well. 相似文献
963.
We review the observations of supernova remnants (SNRs) and pulsar-wind nebulae (PWNe) that give information on the strength and orientation of magnetic fields. Radio polarimetry gives the degree of order of magnetic fields, and the orientation of the ordered component. Many young shell supernova remnants show evidence for synchrotron X-ray emission. The spatial analysis of this emission suggests that magnetic fields are amplified by one to two orders of magnitude in strong shocks. Detection of several remnants in TeV gamma rays implies a lower limit on the magnetic-field strength (or a measurement, if the emission process is inverse-Compton upscattering of cosmic microwave background photons). Upper limits to GeV emission similarly provide lower limits on magnetic-field strengths. In the historical shell remnants, lower limits on B range from 25 to 1000?μG. Two remnants show variability of synchrotron X-ray emission with a timescale of years. If this timescale is the electron-acceleration or radiative loss timescale, magnetic fields of order 1?mG are also implied. In pulsar-wind nebulae, equipartition arguments and dynamical modeling can be used to infer magnetic-field strengths anywhere from ~5?μG to 1?mG. Polarized fractions are considerably higher than in SNRs, ranging to 50 or 60% in some cases; magnetic-field geometries often suggest a toroidal structure around the pulsar, but this is not universal. Viewing-angle effects undoubtedly play a role. MHD models of radio emission in shell SNRs show that different orientations of upstream magnetic field, and different assumptions about electron acceleration, predict different radio morphology. In the remnant of SN 1006, such comparisons imply a magnetic-field orientation connecting the bright limbs, with a substantial density gradient across the remnant. 相似文献
964.
B Yendler 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1998,22(10):1419-1423
There is a need for reliable methods of measuring the level and distribution of water in the solid substrates that are used for growing plants in space. In a microgravity environment, water distribution is governed generally by capillary forces. Arcillite is the solid substrate used in the ASTROCULTURE (TM) system which was developed for growing plants in space. The goal of this study is to evaluate the applicability of heat pulse moisture sensors for measuring moisture levels in Arcillite. The ASTROCULTURE system uses suction as a means of controlling the moisture level in Arcillite, but the spatial distribution of the moisture is left unknown. Studies of the moisture content in a cell experiment were conducted to calibrate a heat pulse moisture sensor and then the sensor was used in a suction experiment to verify moisture content and distribution. Results of the studies demonstrate that head pulse moisture sensors can be used to monitor moisture content and distribution within the root module of the ASTROCULTURE system. 相似文献
965.
The question of how multiple-pass data from the Navy Satellite System can be processed to yield an optimal estimate of the latitude, longitude, and elevation of a point on the Earth's surface is considered. It is demonstrated that the problem can be treated by use of modern estimation techniques. Two methods are considered: Kalman estimation and weighted least-squares estimation. The variance of the estimation errors is compared for a simulated sequence of 50 satellite passes. 相似文献
966.
N. A. Protasova 《Russian Aeronautics (Iz VUZ)》2011,54(3):285-291
Some results obtained in the course of structural investigations with the use of the methods of scanning electron microscopy
and X-ray structure analysis of operating temperature influence upon dynamics of the hardened state relaxation in the turbine
blade roots are discribed. Also considered are the data on determining the residual surface stresses by Davidenkov’s method
and that of the X-ray diffractometry. 相似文献
967.
T.P. Dachev B.T. Tomov Yu.N. Matviichuk P.S. Dimitrov S.V. Vadawale J.N. Goswami G. De Angelis V. Girish 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
The RADiatiOn Monitor (RADOM) is a miniature dosimeter-spectrometer that flew onboard the Chandrayaan-1 lunar mission in order to monitor the local radiation environment. Primary objective of the RADOM experiment was to measure the total absorbed dose, flux of surrounding energetic particles and spectrum of the deposited energy from high energy particles both en-route and in lunar orbit. RADOM was the first experiment to be switched on after the launch of Chandrayaan-1 and was operational until the end of the mission. This paper summarizes the observations carried out by RADOM during the entire life time (22 October 2008–31 August 2009) of the Chandrayaan-1 mission and compares the measurement by RADOM with the radiation belt models such as AP-8, AE-8 and CRRESS. 相似文献
968.
The Magnetospheric Multiscale Magnetometers 总被引:2,自引:0,他引:2
C. T. Russell B. J. Anderson W. Baumjohann K. R. Bromund D. Dearborn D. Fischer G. Le H. K. Leinweber D. Leneman W. Magnes J. D. Means M. B. Moldwin R. Nakamura D. Pierce F. Plaschke K. M. Rowe J. A. Slavin R. J. Strangeway R. Torbert C. Hagen I. Jernej A. Valavanoglou I. Richter 《Space Science Reviews》2016,199(1-4):189-256
The success of the Magnetospheric Multiscale mission depends on the accurate measurement of the magnetic field on all four spacecraft. To ensure this success, two independently designed and built fluxgate magnetometers were developed, avoiding single-point failures. The magnetometers were dubbed the digital fluxgate (DFG), which uses an ASIC implementation and was supplied by the Space Research Institute of the Austrian Academy of Sciences and the analogue magnetometer (AFG) with a more traditional circuit board design supplied by the University of California, Los Angeles. A stringent magnetic cleanliness program was executed under the supervision of the Johns Hopkins University’s Applied Physics Laboratory. To achieve mission objectives, the calibration determined on the ground will be refined in space to ensure all eight magnetometers are precisely inter-calibrated. Near real-time data plays a key role in the transmission of high-resolution observations stored on board so rapid processing of the low-resolution data is required. This article describes these instruments, the magnetic cleanliness program, and the instrument pre-launch calibrations, the planned in-flight calibration program, and the information flow that provides the data on the rapid time scale needed for mission success. 相似文献
969.
970.
L Lamotte B Saugier D T Smernoff M Andre 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1999,24(3):303-308
A simplified closed system consisting of a plant growth chamber coupled to a decomposition chamber was used to study carbon exchange dynamics. The CO2 produced via the decomposition of wheat straw was used for photosynthetic carbon uptake by wheat plants. The atmosphere of the two chambers was connected through a circuit of known flow rate. Thus, monitoring the CO2 concentrations in both compartments allowed measurement of the carbon exchange between the chambers, and estimation of the rate of respiration processes in the decomposition chamber and photosynthetic rate in the producer chamber. The objective for CELSS research was to simulate a system where a compartment producing food via photosynthesis, would be supplied by CO2 produced from respiration processes. The decomposition of biomass by the decomposer simulated both the metabolism of a crew and the result of a recycling system for inedible biomass. Concerning terrestrial ecosystems, the objective was to study organic matter decomposition in soil and other processes related to permanent grasslands. 相似文献