排序方式: 共有32条查询结果,搜索用时 0 毫秒
1.
Radiation measurements made onboard the MIR Orbital Station have spanned nearly a decade and covered two solar cycles, including one of the largest solar particle events, one of the largest magnetic storms, and a mean solar radio flux level reaching 250 x 10(4) Jansky that has been observed in the last 40 years. The cosmonaut absorbed dose rates varied from about 450 microGy day-1 during solar minimum to approximately half this value during the last solar maximum. There is a factor of about two in dose rate within a given module, and a similar variation from module to module. The average radiation quality factor during solar minimum, using the ICRP-26 definition, was about 2.4. The drift of the South Atlantic Anomaly was measured to be 6.0 +/- 0.5 degrees W, and 1.6 +/- 0.5 degrees N. These measurements are of direct applicability to the International Space Station. This paper represents a comprehensive review of Mir Space Station radiation data available from a variety of sources. 相似文献
2.
Kerry Lee Lawrence Pinsky Vic Andersen Cary Zeitlin Tim Cleghorn Frank Cucinotta Premkumar Saganti William Atwell Ron Turner 《Radiation measurements》2006,41(9-10):1123-1125
The helium energy spectrum in Martian orbit has been observed by the MARIE charged particle spectrometer aboard the 2001 Mars Odyssey spacecraft. The orbital data were taken from March 13, 2002 to October 28, 2003, at which time a very intense Solar Particle Event caused a loss of communication between the instrument and the spacecraft. The silicon detector stack in MARIE is optimized for the detection of protons and helium in the energy range below , which typically includes almost all of the flux during SPEs. This also makes MARIE an efficient detector for GCR helium in the energy range of 50–. We will present the first fully normalized flux results from MARIE, using helium ions in this energy range. 相似文献
3.
4.
5.
The dose rate dynamics of the October 19-20, 1989 solar energetic particle (SPE) event as observed by the Liulin instrument onboard the Mir orbital station was analyzed in light of new calculations of the geomagnetic cutoff and improved estimates of the >100 MeV energy spectra from the GOES satellite instrument. The new calculations were performed using the as-flown Mir orbital trajectory and includes time variations of the cutoff rigidity due to changes in the Kp index. Although the agreement of total event integrated calculated dose to the measured dose is good, it results from some measured dose-time profile being higher and some lower than model calculations. They point to the need to include the diurnal variation of the geomagnetic cutoff and modifications of the cutoffs to variations in Kp in model calculations. Understanding of such events in light of the upcoming construction of the International Space Station during the period of maximum solar activity needs to be vigorously pursued. 相似文献
6.
This paper demonstrates the strong interaction between molecular iodine and surface atoms of III - V compounds such as InP and GaP.The mechanism of the iodine reduction is determined. 相似文献
7.
8.
Sean T. Brennan Norman L. Colbry Robert L. Leeds Boguslawa Leja Stephen R. Priebe Michael D. Reily H. D. Hollis Showalter Susan E. Uhlendorf Graham J. Atwell William A. Denny 《Journal of heterocyclic chemistry》1989,26(5):1469-1476
An improved process for the synthesis of bulk quantities of the clinical amsacrine analog CI-921 is reported. Described also are detailed analytical and spectroscopic data for this agent. 相似文献
9.
Aromatic asymmetric halomesylate mustards are efficiently prepared by reaction of activated aromatic chlorides with aziridineethanol/alkali metal halides, followed by mesylation of the haloalcohol. The reaction conditions are sufficiently mild to be compatible with a range of different substituents and protecting groups, including carboxylate and phosphate esters, and have been used in an improved synthesis of the anticancer bromomesylate mustard PR-104, now in clinical trials. 相似文献
10.
Bridget M. Sykes Graham J. Atwell William A. Denny Charmian J. O'Connor 《Journal of Physical Organic Chemistry》1995,8(9):587-596
The reductive cyclization of several 2-nitroarylamides was studied by radiolytic reduction, examining the effects of substituents on the nitrophenyl ring and on the leaving aniline and variations in the nature of the link between the nitrophenyl ring and the leaving aniline. The stoichiometry of the reduction and the identification of N-hydroxylactam and aniline products suggest that the major initial products of such a reduction of the nitroamides are the corresponding hydroxylamines. Under anaerobic conditions, cyclization via the hydroxylamines was considerably faster (up to 160-fold) than via the corresponding amines under comparable conditions, but was similarly influenced by changes in geometry. Unlike cyclization via the amines, rates of cyclization via the hydroxylamines were sensitive to substitution on the leaving aniline, being accelerated by electron-withdrawing groups. The rate-determining step in the cyclization of the hydroxylamines is proposed to be breakdown of the tetrahedral intermediate. 相似文献