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排序方式: 共有87条查询结果,搜索用时 360 毫秒
71.
K.C. Kim K. Abe H. Fuke T. Hams M.H. Lee Y. Makida S. Matsuda J.W. Mitchell J. Nishimura J.F. Ormes M. Sasaki E.S. Seo Y. Shikaze R.E. Streitmatter J. Suzuki K. Tanaka T. Yamagami A. Yamamoto T. Yoshida K. Yoshimura 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
The Balloon-borne Experiment with a Superconducting Spectrometer (BESS) was flown from Lynn Lake, Manitoba, Canada in August, 2000, during the maximum solar modulation period, with an average residual atmospheric overburden of 4.3 g/cm2. Precise spectral measurements of cosmic ray hydrogen isotopes from 0.178 GeV/n to 1.334 GeV/n were made during the 28.7 h of flight. This paper presents the measured energy spectra and their ratio, 2H/1H. The results are also compared with previous measurements and theoretical predictions. 相似文献
72.
M. Horányi V. Hoxie D. James A. Poppe C. Bryant B. Grogan B. Lamprecht J. Mack F. Bagenal S. Batiste N. Bunch T. Chanthawanich F. Christensen M. Colgan T. Dunn G. Drake A. Fernandez T. Finley G. Holland A. Jenkins C. Krauss E. Krauss O. Krauss M. Lankton C. Mitchell M. Neeland T. Reese K. Rash G. Tate C. Vaudrin J. Westfall 《Space Science Reviews》2008,140(1-4):387-402
The Student Dust Counter (SDC) experiment of the New Horizons Mission is an impact dust detector to map the spatial and size distribution of dust along the trajectory of the spacecraft across the solar system. The sensors are thin, permanently polarized polyvinylidene fluoride (PVDF) plastic films that generate an electrical signal when dust particles penetrate their surface. SDC is capable of detecting particles with masses m>10?12 g, and it has a total sensitive surface area of about 0.1 m2, pointing most of the time close to the ram direction of the spacecraft. SDC is part of the Education and Public Outreach (EPO) effort of this mission. The instrument was designed, built, tested, integrated, and now is operated by students. 相似文献
73.
High energy neutral atom (hena) imager for the IMAGE mission 总被引:1,自引:0,他引:1
Mitchell D.G. Jaskulek S.E. Schlemm C.E. Keath E.P. Thompson R.E. Tossman B.E. Boldt J.D. Hayes J.R. Andrews G.B. Paschalidis N. Hamilton D.C. Lundgren R.A. Tums E.O. Wilson P. Voss H.D. Prentice D. Hsieh K.C. Curtis C.C. Powell F.R. 《Space Science Reviews》2000,91(1-2):67-112
The IMAGE mission will be the first of its kind, designed to comprehensively image a variety of emissions from the Earth's magnetosphere, with sufficient time resolution to follow the dynamics associated with the development of magnetospheric storms. Energetic neutral atoms (ENA) emitted from the ring current during storms are one of the key emissions that will be imaged. This paper describes the characteristics of the High Energy Neutral Atom imager, HENA. Using pixelated solid state detectors, imaging microchannel plates, electron optics, and time of flight electronics, HENA is designed to return images of the ENA emitting regions of the inner magnetosphere with 2 minute time resolution, at angular resolution of 8 degrees or better above the energy of 50 keV/nucleon. HENA will also image separately the emissions in hydrogen, helium, and oxygen above 30 keV/nucleon. HENA will reject energetic ions below 200 keV/charge, allowing ENA images to be returned in the presence of ambient energetic ions. HENA images will reveal the distribution and the evolution of energetic ion distributions as they are injected into the ring current during geomagnetic storms, as they drift about the Earth on both open and closed drift paths, and as they decay through charge exchange to pre-storm levels. Substorm ion injections will also be imaged, as will the regions of low altitude, high latitude ion precipitation into the upper atmosphere. 相似文献
74.
75.
Sara E. Mitchell Emilie Drobnes M. Sol Colina-Trujillo Jacob Noel-Storr 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008
Parents and families have the greatest influence on children’s attitudes towards education and career choices. If students’ attitudes towards science, particularly the physical sciences, are not influenced positively by parental/familial attitudes, efforts to improve the quality of content and teaching of these subjects in school may be futile. Research shows that parental involvement increases student achievement outcomes, and family-oriented programs have a direct impact on student performance. 相似文献
76.
B. H. Mauk J. B. Blake D. N. Baker J. H. Clemmons G. D. Reeves H. E. Spence S. E. Jaskulek C. E. Schlemm L. E. Brown S. A. Cooper J. V. Craft J. F. Fennell R. S. Gurnee C. M. Hammock J. R. Hayes P. A. Hill G. C. Ho J. C. Hutcheson A. D. Jacques S. Kerem D. G. Mitchell K. S. Nelson N. P. Paschalidis E. Rossano M. R. Stokes J. H. Westlake 《Space Science Reviews》2016,199(1-4):471-514
77.
Tze Chao Chiam Yuehwern Yih Cary Mitchell 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2010
The Advanced Life Support/NASA Specialized Center of Research and Training (ALS/NSCORT) focuses on research and development of technologies to support human habitation during space missions. This research was done as part of an effort to maintain crewmembers’ water supply in a closed life-support system. The water subsystem was the primary focus of this study because water is one of the most expensive and important resources for human survival. 相似文献
78.
Phase shift for the ramp-comparator pulsewidth modulator (PWM) between a continuous input control signal and the signal frequency component of the output is analyzed. It is shown that transport lag is not implicit to these PWM systems in general but rather depends upon the existence of explicit delays between the time at which a switching decision is made and the time at which that decision is executed. 相似文献
79.
C Mitchell L Sherman S Nielsen P Nelson P Trumbo T Hodges P Hasegawa R Bressan M Ladisch D Auslander 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1996,18(4-5):23-31
Earth benefits of research from the NSCORT in Bioregenerative Life Support will include the following: development of active control mechanisms for light, CO2, and temperature to maximize photosynthesis of crop plants during important phases of crop development; automation of crop culture systems; creation of novel culture systems for optimum productivity; creation of value-added crops with superior nutritional, yield, and waste-process characteristics; environmental control of food and toxicant composition of crops; new process technologies and novel food products for safe, nutritious, palatable vegetarian diets; creation of menus for healthful vegetarian diets with psychological acceptability; enzymatic procedures to degrade recalcitrant crop residues occurring in municipal waste; control-system strategies to ensure sustainabilty of a CELSS that will enable management of diverse complex systems on Earth. 相似文献
80.
Heidbreder Glenn R. Mitchell Richard L. 《IEEE transactions on aerospace and electronic systems》1967,(1):5-13
The amplitude and power of a large family of radio signals are observed to have log-normal probability density functions. Among these are signals propagated through random inhomogeneous media, a notable example being low frequency atmospheric radio noise. Of greater importance are certain radar targets that have been observed to have essentially log-normal density functions. Both ships and space vehicles may fall into this category. Curves of probability of detection vs. signal-to-noise ratio for the case of log-normal signals in Gaussian noise have been computed and are presented in this paper. The curves apply for square-law detection with varying degrees of postdetection linear integration. Both fully correlated and completely uncorrelated fluctuating signals are considered. It is shown that for log-normal signal distributions having large variances, the probability of detection differs significantly from that obtained using curves based on an assumed Rayleigh signal distribution. 相似文献