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941.
T. L. Landecker 《Space Science Reviews》2012,166(1-4):263-280
Synchrotron radiation is generated throughout the Milky Way. It fills the sky, and carries with it the imprint of the magnetic field at the point of origin and along the propagation path. Observations of the diffuse polarized radio emission should be able to provide information on Galactic magnetic fields with detail matching the angular resolution of the telescope. I review what has been learned from existing data, but the full potential cannot be realized from current observations because they do not adequately sample the frequency structure of the polarized emission, or they lack information on large-scale structure. I discuss three surveys, each overcoming one of these limitations, and show how use of complementary data on other ISM tracers can help elucidate the role of magnetic fields in interstellar processes. The focus of this review is on the small-scale field, on sizes comparable with the various forms of interaction of stars with their surroundings. The future is bright for this field of research as new telescopes are being built, designed for the survey mode of observation, equipped for wideband, multichannel polarization observations. 相似文献
942.
A method for deconvolving equatorial pitch angle distributions of energetic neutral atoms from images from the ENA instruments on the IMAGE satellite is described and illustrated using simulated data obtained from calculated models of ring current flux. The unknown flux is expanded in terms of cubic B-splines and Legendre polynomials. The expansion coefficients are obtained from the solution of a linear set of equations that select the smoothest solution that fits the data. In this way, all the information that is contained in the data is extracted but no more. 相似文献
943.
The Advanced Composition Explorer (ACE) mission is supported by the ACE Science Center for the purposes of processing and
distributing ACE data, and facilitating collaborative work on the data by instrument investigators and by the space physics
community at large. The Science Center will strive to ensure that the data are properly archived and easily available. In
particular, it is intended that use of a centralized science facility will guarantee appropriate use of data formatting standards,
thus easing access to the data, will improve communications within and to the ACE science working team, and will reduce redundant
effort in data processing. Secondary functions performed by the Science Center include acting as an interface between the
scientists and the mission operations team.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
944.
C Schimek P Eibel T Horie P Galland T Ootaki 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1999,24(6):687-696
The sporangiophores of the zygomycete fungus Phycomyces blakesleeanus contain octahedral crystals with diameters of up to 5 micrometers in their vacuole. The crystals are associated with the intracellular membrane system. In tilted or horizontally placed sporangiophores, the crystals sediment to the respective lower face of the vacuole with a velocity of up to 100 micrometers per minute. The sedimentation is completed within about 2 minutes, well within the latency period for the negative gravitropic response of Phycomyces. Crystal-lacking mutant strains display a smaller maximal bending angle and a reduced gravitropic bending rate in comparison to the wild type. We therefore conclude that the crystals serve as statoliths for gravitropism in Phycomyces. 相似文献
945.
Glisson T.H. Black C.I. Sage A.P. 《IEEE transactions on aerospace and electronic systems》1970,(1):37-50
Systems which utilize acoustic energy to explore an undersea environment are called sonars. This introductory and tutorial paper presents a discussion of active sonar signal analysis concentrating upon sinusoidal, linear FM, and pseudorandom echolocation pulses. Many previously published results concerning sonar signals and their haracteristics are integrated, collected, and presented in a unified form such as to portray typical signal design considerations. 相似文献
946.
A typical function of an angle tracking loop is to keep a radar antenna pointed at a target. The error in pointing is directly related to successful operation of the tracking device; therefore, its behavior is of interest. For a tracker with a general polynomial nonlinearity, an arbitrary initial pointing error, and a bounded deterministic input, a method is developed for finding upper bounds on the magnitude of the tracking error using Volterra series techniques. Convergence regions of the Volterra series are also obtained. Applications of these results are made to a second-order tracking device. 相似文献
947.
To realize the maximum potential of large series connected battery packs, the individual battery voltages should be maintained at fairly uniform values, i.e., the voltages should be equalized. The ramp type of electronic equalizer has proven to be very effective in performing this task since it offers the advantages of simplicity and convenience. However, to achieve maximum performance, it is necessary to understand how the circuit is affected by certain parameters. This is accomplished by defining the circuit sensitivity and using a simplified model to explain the relative effects of leakage inductance, frequency, and power level 相似文献
948.
M. Yamashita T. Naitoh A. Kashiwagi Y. Kondo R. J. Wassersug 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1999,23(12):2083-2086
Frogs and toads turn either their heads or bodies opposite to angular accelerations applied around the yaw axis. Thresholds exist for the minimum angular acceleration that induces this vestibulomotor response in individual frogs. These thresholds were recorded for several anuran species that cover a broad range of sizes and life styles. Interspecific variation in the magnitude of the thresholds, which correlated with the ecology and behavior of the species, was documented. Also an allometric relationship was observed between this threshold and body size; the larger the frog, the lower the threshold. In many species, the threshold value for reflexive vestibulomotor responses to angular acceleration was proportional to the -0.4 (+/-0.2) power of body mass. Physical dimensions of the semicircular canals determine, in part, vestibular sensitivity to angular acceleration. Hence changes with growth in the semicircular canals are believed to contribute to the slope of -0.4. The biological significance of this allometry in vestibular responses is discussed and compared to trends in vestibular sensitivity and semicircular canal morphology of other vertebrate classes. 相似文献
949.
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
950.
The efficacy of employing battery condition management equipment and procedures is demonstrated on the solid basis of field experience in which the host batteries were found either to be flawed or operated in ways that would compromise reliability. Examples found using such equipment and reported in this paper include a cell whose voltage vacillated daily while on float, post/strap joints whose accept/reject connection integrity was erratic with time, chargers whose voltages were improperly set (both high and low), and a battery room environment whose conditions were life-shortening to electrolytic cells 相似文献