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51.
R. Vaccarone A. Morozzo della Rocca A. Pilot F. Vivaldi C. Rizzuto 《Solid State Communications》1973,12(9):885-889
Measurements on the superconducting critical temperature Tc and critical field, Hc, of Cr and Mn alloys, down to 0.037°K are presented.The variation of Tc with increasing concentration depends strongly on Tcp/θ, with θ a characteristic temperature, while effects of Hc are similar to previously studied alloys. 相似文献
52.
Measurements of the diffusion coefficient of Kr in Xe at T = 298 K and in the density range 0–200 amagat are reported. The data are analyzed in order to investigate whether a logarithmic divergence appears in the density expansion of the diffusion coefficient. This analysis shows that a power series expansion is more consistent with our data though the presence of the logarithmic term can not be excluded. The values of the first coefficients of the power series expansion are compared with the theoretical predictions. 相似文献
53.
We consider the constrained vector optimization problem min C f(x), g(x) ∈ ?K, where f:? n →? m and g:? n →? p are C 1,1 functions, and C ? m and K ? p are closed convex cones with nonempty interiors. Two type of solutions are important for our considerations, namely w-minimizers (weakly efficient points) and i-minimizers (isolated minimizers). We formulate and prove in terms of the Dini directional derivative second-order necessary conditions for a point x 0 to be a w-minimizer and second-order sufficient conditions for x 0 to be an i-minimizer of order two. We discuss the reversal of the sufficient conditions under suitable constraint qualifications of Kuhn-Tucker type. The obtained results improve the ones in Liu, Neittaanmäki, K?í?ek [21]. 相似文献
54.
Well collimated electron beam discharges with an energy of 1 kW, at currents up to 0.1 A, have been obtained at ambient pressures up to 0.4 Torr in Ar and 1.4 Torr in He using hollow cathode electron guns. The guns operate on a continuous or dc basis. These guns have the unique feature of providing a clear optical path through the axis. We suggest the use of such an electron beam discharge for excitation of cw ion lasers. 相似文献
55.
The influence of the amount of water dissolved in dichloromethane on the chromatographic separation of herbicides was studied. The selectivity of the mobile phase was demonstrated and compared to another system, dichloromethane modified with 2-propanol. The high efficiency of microporous packing was also demonstrated. 相似文献
56.
P. F. Moulton W. Künzel U. Dürr A. Beimowski G. Huber D. Pruss V. V. Laptev I. A. Shcherbakov Y. V. Zharikov B. Struve J. M. Eggleston T. Kane R. L. Byer J. Unternahrer R. G. Harrison M. R. Taghizadeh A. K. Kar P. K. Gupta D. J. Jackson J. J. Wynne J. J. Rocca J. D. Meyer Zeng-qi Yu G. J. Collins 《Applied physics. B, Lasers and optics》1982,28(2-3):233-239
57.
Abstract— Single-strand breaks are produced in the phosphodiester backbone of ultraviolet-light-irradiated 5–bromodeoxyuridine-containing DNA (BU-DNA) after treatment with alkali. No radiation dependent breakage is observed in thymine-containing DNA (thy-DNA). The relative yields of breaks terminated by 5'-hydroxyl and 5'-phosphate groups was determined by measuring the rate of phosphorylation achieved with polynucleotide kinase in BU-DNA single strands before and after treatment with alkaline phosphatase. The ratio of 5'-phosphate to 5' hydroxyl groups ranged from 2.3 to 2.9 in different experiments. When cysteamine was present during irradiation no new end groups were produced.
In order to identify the nucleoside(s) at the 5'-termini, phosphate groups were removed with alkaline phosphatase and the 5'-hydroxyl groups were phosphorylated with polynucleotide kinase. Electrophoresis of enzymatic digests showed a single32 P-labeled component migrating more rapidly than any of the four usual 5'-mononucleotides. Upon column chromatography this component resolved into a major peak coincident with 5'-dUMP and a lesser unidentified constituent. No 5'-dBUM32 P was observed among these nucleotides. 相似文献
In order to identify the nucleoside(s) at the 5'-termini, phosphate groups were removed with alkaline phosphatase and the 5'-hydroxyl groups were phosphorylated with polynucleotide kinase. Electrophoresis of enzymatic digests showed a single
58.
An additive corrugated potential with linear repulsion and long range attractive well is proposed for atom-surface scattering. The computational procedure yielding the scattering probabilities (essentially linear algebra) proves to be much simpler than with other potentials. For a given shape of the corrugation function and for high values of the steepness parameter one obtains results close to those of the hard corrugated wall model, while an important enhancement of the specular intensity appears, in particular at large angles of incidence, when the steepness parameter is small. 相似文献
59.
Richard P. Chartoff Thomas S.K Lo E. Ray Harrell JR Ryong Joon Roe 《Journal of Macromolecular Science: Physics》2013,52(3):287-303
The influence of crystallinity and stereoregularity on the infrared (IR) spectrum of atactic PVC in the solid state has been studied by many researchers [1-12]. Although the molecules in commercial PVC consist of both syndiotactic and isotactic sequences, the bulk polymer is not highly stereoregular, having approximately 50% syndiotacticity. Its infrared spectrum is different from that of highly syndiotactic PVC [3,5,7,9,10-12], particularly in the carbon-to-chlorine stretching region where there are three bands located at 610(615), 635, and 690 cm?1. These three bands are known to be of complex origin, since each band consists of more than one absorption frequency and its relative intensity depends on the physical state or history of the specimen [3,5,7,9,10-12]. The spectrum in this region is most rigorously interpreted in terms of chain conformational structure, the spatial arrangement of the atoms around the C-C1 bond. Thus, while changes in absorbance intensities for the bands with history do not necessarily reflect changes in crystallinity, their history dependence renders these bands potentially useful as crystallinity indicators. 相似文献
60.
INTRODUCTION The tensor associated with a Raman band plays an important role in determining the band intensity and its structural significance. Each Raman tensor interrelates two electric vectors, that of the exciting radiation (i.e. laser photon) and that of the Raman scattered radiation (i.e. the inelastically scattered photon which results from the exchange of a vibrational quantum between the exciting photon and the molecule). The Raman tensor is obtained formally as the first derivative of the molecular polarizability tensor, the derivative being taken with respect to the vibrational normal coordinate. In other words, the Raman tensor associated with a vibrational Raman band is an indicator of how the polarizability of the molecule oscillates with the molecular normal mode of vibration. 相似文献