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81.
S Biswas R Chakraborti R Cowsik N Durgaprasad P J Kajarekar R K Singh M N Vahia J S Yadav N Dutt J N Goswami D Lal H S Mazumdar D V Subhedar M K Padmanabhan 《Pramana》1986,27(1-2):89-104
The measurements of the ionization states, composition, energy spectra and spatial distribution of heavy ions of helium to
iron of energies 10–100 MeV/amu in the anomalous cosmic rays are of major importance in understanding their origin which is
unknown at present.Anuradha (IONS) cosmic ray experiment in Spacelab-3 was designed to determine the above properties in near earth space and this had
a highly successful flight and operations aboard the shuttle Challenger at an orbital altitude of 352 km during 29 April to
6 May 1985. The instrument employs solid state nuclear track detectors (CR-39) of high sensitivity and large collecting area
of about 800 cm2 and determines the arrival time information of particles with active elements. Experimental methods, flight operations and
preliminary results are briefly described. Initial results indicate that relatively high fluxes of low energy cosmic ray α-particles,
oxygen group and heavier ions were obtained. The flight period corresponded to that of quiet Sun and the level of solar activity
was close to solar minimum. It is estimated that about 10,000 events of low energy cosmic ray alpha particles with time annotation
are recorded in the detector together with similar number of events of oxygen and heavier ions of low energy cosmic rays.
The authors felicitate Prof. D S Kothari on his eightieth birthday and dedicate this paper to him on this occasion. 相似文献
82.
用低杂波驱动电流的等离子体电导率 总被引:1,自引:1,他引:0
印永祥 《核聚变与等离子体物理》1988,(2)
本文用Liu的低杂波驱动电流模型,导出了弱场近似下低杂波驱动电流的等离子体电导率。结果表明,电导率对磁场B_0,电子密度n_0,以及电子温度T_e非常敏感。而这些参量决定着共振电子的数目和速度。 相似文献
83.
求解了恒定均匀的强磁场中核子的能谱和波函数,在手征表象中给出含核子反常磁矩(AMM)项的Dirac方程的解;并且计算了中子星内壳层物质的物态方程(EOS)和粒子丰度,发现在强磁场中磁能将使中子星内壳层的压强增加但物质仍然是丰中子,AMM项对质子的极化度有明显效应. 相似文献
84.
L. A. S. De A. Prado H. Wittich K. Schulte G. Goerigk Vasil M. Garamus R. Willumeit S. Vetter B. Ruffmann S. P. Nunes 《Journal of Polymer Science.Polymer Physics》2004,42(3):567-575
The morphology and distribution of zirconium oxide and zirconium phosphates in a matrix of sulfonated poly(ether ether ketone) (SPEEK) were investigated with anomalous small‐angle X‐ray scattering (ASAXS) and electron microscopy. ASAXS revealed that ZrO2 was distributed in the SPEEK matrix in the form of nanoparticles smaller than 13 Å. A decrease in the conductivity suggested that the sulfonic groups were bound to the zirconium oxo species at the particle surface. Furthermore, two kinds of membranes containing zirconium phosphate were investigated. In one case, the phosphate was directly dispersed in the polymer solution for the casting of the membrane. In the other case, the phosphate was previously treated with n‐propyl ammonium and polybenzimidazole. From ASAXS data, the fractal dimension could be estimated. Mass‐fractal behavior was confirmed for the SPEEK membrane containing previously exfoliated zirconium phosphate, with aggregates of 6.3–165 Å. Surface‐fractal behavior was detected for membranes with untreated phosphates, with aggregates of 6.4–185 Å. The untreated phosphates caused an increase in the permeability, without changing the proton conductivity much. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 567–575, 2004 相似文献
85.
K. Nagarajan P. Rajagopalan B. G. Advani V. Ranga Rao G. A. Bhat 《Journal of Chemical Sciences》1992,104(3):383-397
2-Amino-2-arylethylamides1 carrying electron-donating substituents in thepara position are transformed by hot POC13 to the the title compounds2, presumably via iminochlorides 7 and imidazolium derivatives8. Amides lacking this para-substituent give rise to chloroamidines11 under these conditions.m-Methoxyphenethylamide1t and POCl3 form, besides11f, an isoquinoline derivative3. The involvement of an imidazolium compound8 in the formation of ethenamidines has been verified by the synthesis of2a from10. Reaction of amide1w with PCl5 in the cold leads to, besides the chloroamidine11c, thecis-ethenamidine12 which equilibrates with thetrans-isomer2o in hot toluene. Thienylethyl urea13 converted by hot POCl3 to the imidazoline16, while phenylpropylamide17 forms only the iminochloride18a.
Contribution No. 752 from Research Centre 相似文献
86.
利用Mie散射与反常衍射理论的数值计算,对球形颗粒Mie散射和反常衍射作了大量详细的计算和分析比较,提出了相对折射率趋近于1的颗粒的反常衍射近似替代Mie散射的判据。 相似文献
87.
Per Dahlqvist 《Journal of statistical physics》1996,84(3-4):773-795
We compute the Lyapunov exponent, the generalized Lyapunov exponents, and the diffusion constant for a Lorentz gas on a square lattice, thus having infinite horizon. Approximate zeta functions, written in terms of probabilities rather than periodic orbits, are used in order to avoid the convergence problems of cycle expansions. The emphasis is on the relation between the analytic structure of the zeta function, where a branch cut plays an important role, and the asymptotic dynamics of the system. The Lyapunov exponent for the corresponding map agrees with the conjectured limit map = -2 log(R) + C + O(R) and we derive an approximate value for the constantC in good agreement with numerical simulations. We also find a diverging diffusion constantD(t)logt and a phase transition for the generalized Lyapunov exponents. 相似文献
88.
A new set of apodizing functions suitable for Fourier transform spectrometers is presented. For this set, two particular functions are discussed in detail. The experimental results show that their characteristics are superior to those of now commonly used in FTS. 相似文献
89.
B. N. Plakhutin E. V. Gorelik N. N. Breslavskaya M. A. Milov A.A. Fokeyev A. V. Novikov T. E. Prokhorov N. E. Polygalova S. P. Dolin L. I. Trakhtenberg 《Journal of Structural Chemistry》2005,46(2):195-203
We present a number of molecular systems for which the average values 〈?2〉 before and after annihilation of the first spin contaminant in the wave function of the unrestricted Hartree-Fock method are anomalously large (they substantially exceed the expected value S (S + 1)). An example of such systems is N@C20, for the doublet state of which the 〈?2〉 values are equal to 4.2595 before and 13.1390 after annihilation, respectively (calculated by UHF/6-31G* method). We show that four, at the least, spin multiplets (S′ = S, S + 1, S + 2, S + 3) contribute comparatively to the wave function of such systems. The relations are derived allowing one to estimate the contributions of the highest multiplets basing on the average values of 〈?2〉 before and after annihilation of the first spin contaminant. 相似文献
90.
Gary W. Slater Christine Villeneuve 《Journal of Polymer Science.Polymer Physics》1992,30(13):1451-1457
The gel electrophoretic migration of streptavidin-DNA complexes is severely altered by the phenomenon known as “trapping electrophoresis.” We present a first computer simulation study of this process. Our simulations use the very efficient biased reptation algorithm. The steady state is characterized by a large increase in band broadening and interband separation. However, we also find that for a narrow range of molecular sizes, the separation power of gel electrophoresis is greatly increased. We discuss the implications of our findings for the possible improvement of DNA sequencing technologies. © 1992 John Wiley & Sons, Inc. 相似文献