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251.
We describe the formation of hot intergalactic gas along with baryonic remnants in galaxy halos. In this scenario, the mass and metallicity of the hot intracluster and intragroup gas relates directly to the production of baryonic remnants during the collapse of galactic halos. We construct a schematic but self-consistent model in which early bursts of star formation lead to a large remnant population in the halo, and to the outflow of stellar ejecta into the halo and ultimately the Local Group. We consider local as well as high redshift constraints on this scenario. This study suggests that the microlensing objects in the Galactic halo may predominantly be 0.5M white dwarfs, assuming that the initial mass function for early star formation favored the formation of intermediate mass stars with m 1M. However, the bulk of the baryonic dark matter in this scenario is associated with the ejecta of the white dwarf progenitors, and resides in the hot intergalactic medium. 相似文献
252.
The sopite syndrome is a poorly understood response to motion. Drowsiness and mood changes are the primary characteristics of the syndrome. The sopite syndrome can exist in isolation from more apparent symptoms such as nausea, can last long after nausea has subsided, and can debilitate some individuals. It is most likely a distinct syndrome from "regular" motion sickness or common fatigue, and is of potential concern in a variety of situations. The syndrome may be particularly hazardous in transportation settings where other performance challenges (e.g., sleep deprivation) are already present. It is also a potential concern in cases where illnesses such as sleep disorders or depression may interact with the syndrome and confuse diagnosis. 相似文献
253.
P Todd D M Klaus L S Stodieck J D Smith L A Staehelin M Kacena B Manfredi A Bukhari 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1998,21(8-9):1263-1268
Our understanding of gravitational effects (inertial effects in the vicinity of 1 x g) on cells has matured to a stage at which it is possible to define, on the basis of experimental evidence, extracellular effects on small cells and intracellular effects on eukaryotic gravisensing cells. Yet undetermined is the nature of response, if any, of those classes of cells that are not governed solely by extracellular physical events (as are prokaryotes) and are devoid of obvious mechanical devices for sensing inertial forces (such as those possessed by certain plant cells and sensory cells of animals). This "in-between" class of cells needs to be understood on the basis of the combination of intracellular and extracellular gravity-dependent processes that govern experimentally-measurable variables that are relevant to the cell's responses to modified inertial forces. The forces that certain cell types generate or respond to are therefore compared to those imposed by approximately 1 x g in the context of cytoskeletal action and symmetry-breaking pathways. 相似文献
254.
Y. Yan J. Huang B. Chen Y. Liu C. Tan 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2010
Radio bursts with fine structures in decimetric–centimetric wave range are generally believed to manifest the primary energy release process during flare/CME events. By spectropolarimeters in 1–2 GHz, 2.6–3.8 GHz, and 5.2–7.6 GHz at NAOC/Huairou with very high temporal (1.25–8 ms) and spectral (4–20 MHz) resolutions, the zebra patterns, spikes, and new types of radio fine structures with mixed frequency drift features are observed during several significant flare/CME events. In this paper we will discuss the occurrence of radio fine structures during the impulsive phase of flares and/or CME initiations, which may be connected to the magnetic reconnection processes. 相似文献
255.
W. Menn O. Adriani G.C. Barbarino G.A. Bazilevskaya R. Bellotti M. Boezio E.A. Bogomolov L. Bonechi M. Bongi V. Bonvicini S. Borisov S. Bottai A. Bruno F. Cafagna D. Campana R. Carbone P. Carlson M. Casolino G. Castellini L. Consiglio M.P. De Pascale C. De Santis N. De Simone V. Di Felice A.M. Galper W. Gillard L. Grishantseva G. Jerse A.V. Karelin S.V. Koldashov S.Y. Krutkov A.N. Kvashnin A. Leonov V. Malakhov V. Malvezzi L. Marcelli A.G. Mayorov V.V. Mikhailov E. Mocchiutti A. Monaco N. Mori N. Nikonov G. Osteria F. Palma P. Papini M. Pearce P. Picozza C. Pizzolotto M. Ricci S.B. Ricciarini 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
256.
To determine the orbital parameters of a satellite using star occultations, it is necessary to measure the intensity of stars as they occult. The accuracy of the intensity measurements is reduced by interfering sources of light and internal noise, and is expressed in terms of the magnitude of various sources of interference. Subsequently, a specific system is analyzed in detail. Moonlit cloud tops introduce the largest systematic error. Photon noise from the star radiation, airglow, and moonlit cloud tops are the largest sources of random errors. 相似文献
257.
258.
Two versions of a microwave feedback radiometer have been built and tested. One used an electromechanical feedback system; the other, an all-electronic system. The response of the servo loops proved to be fast enough and linear enough for almost any radiometer application. The rms noise fluctuation was the same as that of a Dicke radiometer. Stability was excellent even under adverse environmental conditions. 相似文献
259.
Shtessel Yuri B. Shkolnikov Ilya A. Levant Arie 《IEEE transactions on aerospace and electronic systems》2009,45(1):110-124
A new smooth second-order sliding mode control (SSOSM) is proposed and proved for a system driven by uncertain sufficiently smooth disturbances. The main target application of this technique, the missile interceptor guidance-control system against targets performing evasive maneuvers, is considered to demonstrate benefits of this design for a two-loop integration of guidance and flight control systems. The designed guidance-control system performance is verified via computer simulations using a miniature hypervelocity kinetic energy endo-atmospheric interceptor planar model. 相似文献
260.