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921.
J. B. Blake B. H. Mauk D. N. Baker P. Carranza J. H. Clemmons J. Craft W. R. Crain A. Crew Y. Dotan J. F. Fennell R. H. Friedel L. M. Friesen F. Fuentes R. Galvan C. Ibscher A. Jaynes N. Katz M. Lalic A. Y. Lin D. M. Mabry T. Nguyen C. Pancratz M. Redding G. D. Reeves S. Smith H. E. Spence J. Westlake 《Space Science Reviews》2016,199(1-4):309-329
922.
Prateek R. Srivastava Sneha A. Gokani Ajeet K. Maurya Rajesh Singh Sushil Kumar B. Veenadhari R. Selvakumaran Abhay K. Singh Devendraa Siingh Janos Lichtenberger 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
One-to-one relation with its causative lightning discharges and propagation features of night-time whistlers recorded at low-latitude station, Allahabad (geomag. lat. 16.05°N, L = 1.08), India, from continuous observations made during 1–7 April, 2011 have been studied. The whistler observations were made using the Automatic Whistler Detector (AWD) system and AWESOME VLF receiver. The causative lightning strikes of whistlers were checked in data provided by World-Wide Lightning Location Network (WWLLN). A total of 32 whistlers were observed out of which 23 were correlated with their causative lightnings in and around the conjugate location (geom. lat. 9.87°S) of Allahabad. A multi-flash whistler is also observed on 1 April with dispersions 15.3, 17.5 and 13.6 s1/2. About 70% (23 out of 32) whistlers were correlated with the WWLLN detected causative lightnings in the conjugate region which supports the ducted mode of propagation at low latitude. The multi-flash and short whistlers also propagated most likely in the ducted mode to this station. 相似文献
923.
We investigate the behavior of mean values of the solar wind’s and interplanetary magnetic field’s (IMF) parameters and their
absolute and relative variations during the magnetic storms generated by various types of the solar wind. In this paper, which
is a continuation of paper [1], we, on the basis of the OMNI data archive for the period of 1976–2000, have analyzed 798 geomagnetic
storms with D
st
≤ −50 nT and their interplanetary sources: corotating interaction regions CIR, compression regions Sheath before the interplanetary
CMEs; magnetic clouds MC; “Pistons” Ejecta, and an uncertain type of a source. For the analysis the double superposed epoch
analysis method was used, in which the instants of the magnetic storm onset and the minimum of the D
st
index were taken as reference times. It is shown that the set of interplanetary sources of magnetic storms can be sub-divided
into two basic groups according to their slowly and fast varying characteristics: (1) ICME (MC and Ejecta) and (2) CIR and
Sheath. The mean values, the absolute and relative variations in MC and Ejecta for all parameters appeared to be either mean
or lower than the mean value (the mean values of the electric field E
y
and of the B
z
component of IMF are higher in absolute value), while in CIR and Sheath they are higher than the mean value. High values
of the relative density variation sN/〈N〉 are observed in MC. At the same time, the high values for relative variations of the velocity, B
z
component, and IMF magnitude are observed in Sheath and CIR. No noticeable distinctions in the relationships between considered
parameters for moderate and strong magnetic storms were observed. 相似文献
924.
Probing the first stars and black holes in the early Universe with the Dark Ages Radio Explorer (DARE) 总被引:1,自引:0,他引:1
Jack O. Burns J. Lazio S. Bale J. Bowman R. Bradley C. Carilli S. Furlanetto G. Harker A. Loeb J. Pritchard 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2012
A concept for a new space-based cosmology mission called the Dark Ages Radio Explorer (DARE) is presented in this paper. DARE’s science objectives include: (1) When did the first stars form? (2) When did the first accreting black holes form? (3) When did Reionization begin? (4) What surprises does the end of the Dark Ages hold (e.g., Dark Matter decay)? DARE will use the highly-redshifted hyperfine 21-cm transition from neutral hydrogen to track the formation of the first luminous objects by their impact on the intergalactic medium during the end of the Dark Ages and during Cosmic Dawn (redshifts z = 11–35). It will measure the sky-averaged spin temperature of neutral hydrogen at the unexplored epoch 80–420 million years after the Big Bang, providing the first evidence of the earliest stars and galaxies to illuminate the cosmos and testing our models of galaxy formation. DARE’s approach is to measure the expected spectral features in the sky-averaged, redshifted 21-cm signal over a radio bandpass of 40–120 MHz. DARE orbits the Moon for a mission lifetime of 3 years and takes data above the lunar farside, the only location in the inner solar system proven to be free of human-generated radio frequency interference and any significant ionosphere. The science instrument is composed of a low frequency radiometer, including electrically-short, tapered, bi-conical dipole antennas, a receiver, and a digital spectrometer. The smooth frequency response of the antennas and the differential spectral calibration approach using a Markov Chain Monte Carlo technique will be applied to detect the weak cosmic 21-cm signal in the presence of the intense solar system and Galactic foreground emissions. 相似文献
925.
Structural health management technologies for inflatable/deployable structures: Integrating sensing and self-healing 总被引:1,自引:0,他引:1
Erik J. Brandon Max Vozoff Elizabeth A. Kolawa George F. Studor Frankel Lyons Michael W. Keller Brett Beiermann Scott R. White Nancy R. Sottos Mark A. Curry David L. Banks Robert Brocato Lisong Zhou Soyoun Jung Thomas N. Jackson Kevin Champaigne 《Acta Astronautica》2011,68(7-8):883-903
Inflatable/deployable structures are under consideration as habitats for future Lunar surface science operations. The use of non-traditional structural materials combined with the need to maintain a safe working environment for extended periods in a harsh environment has led to the consideration of an integrated structural health management system for future habitats, to ensure their integrity. This article describes recent efforts to develop prototype sensing technologies and new self-healing materials that address the unique requirements of habitats comprised mainly of soft goods. A new approach to detecting impact damage is discussed, using addressable flexible capacitive sensing elements and thin film electronics in a matrixed array. Also, the use of passive wireless sensor tags for distributed sensing is discussed, wherein the need for on-board power through batteries or hardwired interconnects is eliminated. Finally, the development of a novel, microencapuslated self-healing elastomer with applications for inflatable/deployable habitats is reviewed. 相似文献
926.
F. Dalla Vedova H. Henrion M. Leipold Th. Girot R. Vaudemont Th. Belmonte K. Fleury O. Le Couls 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
SSM (Solar Sail Materials) is an on-going project for the European Space Agency (ESA) relying on past and recent European solar sail design projects. It aims at developing and testing future technologies suitable for large, operational solar sailcrafts. 相似文献
927.
928.
In this paper, the results of calculating the processes of two fuel mixture combustion in different proportions are presented.
The values of temperature, thermal capacity, specific gas constant and isentropic expansion ratio of combustion products are
given. Also shown is the distinction of thermodynamic properties from the additivity law. 相似文献
929.
A finite element statement of solving problems on stability of reinforced elliptic cylindrical shells taking into account
momentness and nonlinearity of their subcritical stress strain state is presented. The explicit expressions for displacements
of noncircular cylindrical shell elements as rigid bodies are determined by integrating the equations obtained by equating
the components of linear strains to zero. These expressions were used to construct the form functions for an efficient quadrilateral
finite element of natural curvature. An efficient numerical algorithm of nonlinear deformation and stability of shells was
developed. The stability of reinforced elliptic cylindrical shells under combined loading by bending moment, transverse boundary
force and internal pressure is analyzed. We also examine how the critical loads are affected by the strain nonlinearity and
ellipticity of shell deformation at the subcritical stage. 相似文献
930.
I. S. Akhmed’yanov 《Russian Aeronautics (Iz VUZ)》2010,53(2):230-234
To complete study [1], the procedure of applying the numerical quadrature method to analyzing the shells of revolution under
axisymmetrical loading is presented. 相似文献