排序方式: 共有34条查询结果,搜索用时 15 毫秒
1.
2.
Baranov DG Dergachev VA Gagarin YF Lyagushin VI Nymmik RA Panasyuk MI Solov'ev AV Yakubovskii EA 《Radiation measurements》2002,35(5):423-431
The results are presented of measurements high-energy particles in a customary manned space station orbit (a 350-450-km altitude, a 51.6 degrees inclination; Salyut-6 and 7, MIR). The particles were recorded by the chambers composed of the Lavsan (polyethyleneterephtalate) solid-state nuclear track detector layers mounted outside a spacecraft for 1-3 years. A high resolution has been attained in the charge and energy spectra of 30-200 MeV/n Fe group particles. The results of measuring the particle fluxes in the space station orbits are used to restore the initial particle energy spectra in terms of the models that describe the galactic and solar cosmic rays and their penetration to the Earth's magnetosphere. The analysis demonstrates a high effectiveness of the described methods when applied to quite a number of space physics problems. 相似文献
3.
Nymmik RA 《Radiation measurements》1999,30(5):669-677
A wide range of the galactic cosmic ray and SEP event flux simulation problems for the near-Earth satellite and manned spacecraft orbits and for the interplanetary mission trajectories are discussed. The models of the galactic cosmic ray and SEP events in the Earth orbit beyond the Earth's magnetosphere are used as a basis. The particle fluxes in the near-Earth orbits should be calculated using the transmission functions. To calculate the functions, the dependences of the cutoff rigidities on the magnetic disturbance level and on magnetic local time have to be known. In the case of space flights towards the Sun and to the boundary of the solar system, particular attention is paid to the changes in the SEP event occurrence frequency and size. The particle flux gradients are applied in this case to galactic cosmic ray fluxes. 相似文献
4.
CLAUDIA L. PARKER OSCAR N. VENTURA STAN K. BURT RAÚL E. CACHAU 《Molecular physics》2013,111(17):2659-2668
We present a general purpose QM-MM-MD engine (DYNGA) designed to test alternative hybrid Hamiltonians geared towards the treatment of problems of interest in structural biology including the use of experimental data constraints. In this first presentation we use DYNGA to explore the behaviour of a traditional QM-MM approach in the treatment of the water—water interaction. We find the potential energy hypersurface for the water dimer computed with the HF 4–31G*/TIP3P hybrid Hamiltonian tends to be too flat. We also explore the effect of using traditional QM-MM techniques on proton wires and conclude there is a need for improvement, possibly addressed by using polarizable force fields. 相似文献
5.
Abstract We analyze the efficiency of the international management of the Bay of Biscay anchovy. While a sharing agreement between France and Spain has been in place since 1992, the fish stock collapsed in 2005 and the fishery closed from 2005 to spring 2010. We consider differences in production technologies between both countries and calibrate our model using data from 1987 to 2009. Our results suggest two sources of rent dissipation under the existing sharing agreement: inefficient quota allocation and production inefficiencies due to inflexible national regulations. We discuss several alternatives to improve management. 相似文献
6.
A newly developed interface coupling a CHN combustion device (elemental analyser 'EA') to an isotope ratio mass spectrometer is described and evaluated. The purpose of the device is to extend the dynamic range of delta(13)C and delta(15)N analysis from less than 2 orders of magnitude to more than 3 orders of magnitude. Carbon isotope ratio measurements of atropine as a model compound have been performed analysing between 1 μg to 5 mg C with acceptable to excellent precision (0.6 to 0.06 per thousand, delta-notation). The correction due to the blank signal is critical for sample amounts smaller than 4 μg C. The maximum sample weight is determined by the combustion capacity of the EA. Larger sample amounts are measured using dilution of a small part of the EA effluent with helium. The dilution mechanism works virtually free of isotope fractionation. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
7.
8.
9.
R. A. Nymmik 《Bulletin of the Russian Academy of Sciences: Physics》2007,71(7):927-929
Some regularities related to solar energetic proton (SEP) events and fluxes have been established. It is shown that the rate of SEP events is proportional to the Wolf numbers and that the distribution functions of SEP events related to both different levels and cycle phases, divided by the sums of Wolf numbers, are identical. It is concluded that extremely large SEP events may also occur in periods of minimum solar activity. This conclusion is confirmed by the experimental data obtained at the end of 2004 and in 2005. 相似文献
10.
R. A. Nymmik 《Bulletin of the Russian Academy of Sciences: Physics》2011,75(6):761-763
An analysis of fluences of solar cosmic rays (SCRs), measured by the ACE (ULEIS, SIS) and GOES satellites for 1998–2006 over
the wide energy range of 0.05 to 500 MeV/nucleon, is performed. It is shown that the energy spectra of the fluences have two
sections described by power functions of the energy per nucleon: a hard spectrum at low energies (E < 1–10 MeV/nucleon) and a soft spectrum at high energies (E > 10–30 MeV/nucleon). The main regularities inherent to the parameters of the spectra of different particles are determined. 相似文献