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101.
The concept and physics of a most peculiar glass (called NASTYGLASS) suffering from the video equivalent of audio cross-over distortion are discussed, and a simple mathematical model developed. The model is used as the basis for a computer simulation of how things would look when viewed through a NASTYGLASS window. Some computer-generated, TV-displayed images of `Einstein-in-NASTYGLASS' are included. Finally, future research is proposed, research that just might lead to a Nobel prize in medicine or physiology! 相似文献
102.
Paul AL Zupanska AK Ostrow DT Zhang Y Sun Y Li JL Shanker S Farmerie WG Amalfitano CE Ferl RJ 《Astrobiology》2012,12(1):40-56
103.
Forecasting of localized debris congestion in the geostationary (GEO) regime is performed to investigate how frequently near-miss events occur for each of the longitude slots in the GEO ring. The present-day resident space object (RSO) population at GEO is propagated forward in time to determine current debris congestion conditions, and new probability density functions that describe where GEO satellites are inserted into operational orbits are harnessed to assess longitude-dependent congestion in “business-as-usual” launch traffic, with and without re-orbiting at end-of-life. Congestion forecasting for a 50-year period is presented to illustrate the need for appropriately executed mitigation measures in the GEO ring. Results indicate that localized debris congestion will double within 50 years under current 80% re-orbiting success rates. 相似文献
104.
105.
The Legislative Update column reports on President Bush's supplemental budget request for the war in Iraq, the formation of a defense caucus in the House of Representatives, stabilized funding for airport security, the Department of Homeland Security budget, NASA's budget request, funding for NASA's aeronautics program, and NASA's new authorization. NASA's FY04 budget request is $15.47 billion, less than 1% more than FY03. The aeronautics program budget request for FY04 is $959 million, a decrease of 8.5% from FY03. Congress is working to introduce a multiyear authorization for NASA during the 108th session. 相似文献
106.
Paul D. Feldman 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1984,4(9):177-184
Since its launch in 1978 the () satellite observatory has been used to record ultraviolet spectra of nearly two dozen comets. These observations have been applied principally to studies of the composition, chemistry and evolution of the gaseous coma and more recently, with the substantially increased data base, to comparative analyses. The observations of Comets Bowell (1982 I) and Cernis (1983?) at a heliocentric distance of ≈ 3.4 AU show these two comets to be virtually identical and pose problems for water ice vaporization models. The most significant recent result from was the discovery of S2 in the Earth-approaching comet IRAS-Araki-Alcock (1983d) and the use of the S2 emission as a monitor of short-term variations in cometary activity. In early 1984, periodic comet Encke was observed for the second time by , this time post-perihelion. 相似文献
107.
Paul L. Rothwell Michael B. Silevitch Lars P. Block 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1985,5(4):47-50
A unified model is developed for the propagation of the Westward Traveling Surge (WTS) which can explain the diversity in the observed surge characteristics. The direction of the surge motion depends on the presence of polarization charges on the poleward boundary. This is related to the efficiency with which the poleward ionospheric currents are closed off into the magnetosphere by the field-aligned currents. Inclusion of the electron-ion recombination rate modifies the surge propagation velocity and leads to explicit expressions for the conductivity profile. Sufficient precipitation current is required to overcome electron-ion recombination in order for the surge to expand. When the precipitating current is less than this threshold the WTS retreats. Therefore, the model describes the ionospheric response to both the expansion and recovery phases of the magnetic substorm. 相似文献
108.
Paul Gorenstein 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1981,1(13):3-18
Extragalactic research studies by the Harvard/Smithsonian group with the Einstein Observatory have emphasized quasars and clusters of galaxies. More than 100 QSO's have been detected, including 20 serendipitous discoveries. The ratio of Lx/Lo for radio loud quasars is on the average 3 times that of radio quiet ones. QSO's with a large intrinsic optical luminosity have a smaller ratio of Lx/Lo. X-ray images of clusters of galaxies reveal a variety of morphological types which may correspond to different stages in their evolution. Several examples of bi-modal clusters have been discovered. An X-ray plume associated with M86 is apparently gas being stripped. From X-ray studies, a mass between 1.7 × 1013Mθ and 4.0 × 1013 Mθ has been derived for M87. 相似文献
109.
Paul AL Levine HG McLamb W Norwood KL Reed D Stutte GW Wells HW Ferl RJ 《Acta Astronautica》2005,56(6):623-628
Spaceflight experiments involving biological specimens face unique challenges with regard to the on orbit harvest and preservation of material for later ground-based analyses. Preserving plant material for gene expression analyses requires that the tissue be prepared and stored in a manner that maintains the integrity of RNA. The liquid preservative RNAlater (Ambion) provides an effective alternative to conventional freezing strategies, which are limited or unavailable in current spaceflight experiment scenarios. The spaceflight use of RNAlater is enabled by the Kennedy space center fixation tube (KFT), hardware designed to provide the necessary containment of fixatives during the harvest and stowage of biological samples in space. Pairing RNAlater with the KFT system provides a safe and effective strategy for preserving plant material for subsequent molecular analyses, a strategy that has proven effective in several spaceflight experiments. Possible spaceflight scenarios for the use of RNAlater and KFTs are explored and discussed. 相似文献
110.
Paul D. Maley 《Acta Astronautica》1985,12(10):755-764
While much of what is known about the performance of spacecraft in flight is learned by monitoring telemetry data streams, this paper describes some unique observations made with ground-based astronomical equipment, done in conjunction with the tenth flight of the U.S. Space Shuttle. The study had two main objectives: to test the ability of low-cost, low-light-level television equipment to monitor satellites in orbit, and to attempt visual and photographic observation of the reentry characteristics of a Space Shuttle Orbiter. Both efforts met with considerable success and are described herein. 相似文献