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排序方式: 共有10000条查询结果,搜索用时 15 毫秒
911.
Let ∑, Г be two n-by-n diagonal matrices with σi,γi as their diagonals. For the inverse eigenvalue problem: look for y∈Rn such that Г + yyT is similar to ∑, we prove thatu also the sufficient condition for the solvability of this inverse problem. Its solution (set) is given explicitly. In some case, the problem is unstable. But we prove that the sums of the square of some contigious components keep stable, i.e., small sum keeps small, large sum has a small relative perturbation, see Theorem 3. 相似文献
912.
研究了十二烷基三苯基溴化鏻(C_(12)PBr)胶束中N,N-二甲基苯胺(DMA)和二苯甲酮(DPK)对芘的荧光猝灭,发现DMA的猝灭行为不符合Stern-Volmer动态猝灭和Turro静态猝灭模型;DPK的猝灭行为不符合Stern-Volmer猝灭模型,但遵从Turro静态猝灭模型。根据DPK的静态猝灭性质测得C_(12)PBr胶束的平均簇集数为15士2,并相应地得到C_(12)PBr的临界胶束浓度为(1.77±0.09)×10~(-3)mol/L,后者与文献值一致。 相似文献
913.
Mode coupling and equilibrium mode distribution conditions in plastic optical fibers 总被引:1,自引:0,他引:1
G. Jiang R.F. Shi A.F. Garito 《Photonics Technology Letters, IEEE》1997,9(8):1128-1130
The equilibrium mode distribution (EMD) condition is critical for optical fiber measurements. In this letter, we examine the achievement of EMD condition inside plastic optical fibers (POF's) under different launch conditions. Our pulse broadening measurements of step-index (SI) POF's as a function of fiber length show that the EMD condition can readily be achieved in an SI POF much shorter than in glass optical fibers. The observation of the EMD condition was also independently verified using the far-field pattern technique. 相似文献
914.
Yu. A. Zarubin 《Fluid Dynamics》1991,26(1):75-81
A displacement model constructed on the assumption of the exchange of components between the volumes of the pore space moving and not moving in the direction of displacement is considered. The theoretical solution is shown to be in good agreement with the actual results of the displacement of oil by water. Criterial equations for predicting the interphase exchange coefficient and the relation between the nonmoving and moving volumes of the pore space are constructed on the basis of a series of experiments in uncemented porous media.Translated from Izvestiya Akademii Nauk SSR, Mekhanika Zhidkosti i Gaza, No. 1, pp. 91–97. January–February, 1991. 相似文献
915.
S. N. Vorob'ev Yu. B. Nechaev S. L. Prosvirnin 《Radiophysics and Quantum Electronics》1992,35(8):440-451
The mutual coupling of the radiating elements in microstrip antennas is studied using a rigorous electrodynamic approach in which the field singularities at the radiator edges are taken into account with analytic accuracy. A spectral method is employed in combination with a method of semi-inversion by extraction of the Green-function singularity. The degree of interaction of the elements of microstrip structures at the fundamental and higher current harmonicsis determined, and the applicability of various approximations is assessed.Radio-Astronomy Institute, Academy of Sciences of Ukraine. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 35, No. 8, pp. 688–701, August, 1992. 相似文献
916.
Malkov Yu. P. Davidyan A. A. Filippov Yu. E. Rotinyan M. A. 《Russian Journal of Applied Chemistry》2002,75(6):946-949
A plasmochemical technique for neutralizing ozone-destroying chladones and fluorine- and chlorine-containing wastes is considered. Experimental results obtained on applying this technique to neutralization of some halogen-containing substances are presented, together with the information gained on using the technological scheme of the process in designing and constructing an industrial installation for neutralizing wastes of a plant manufacturing polytetrafluoroethylene. 相似文献
917.
R. L. Safiullin L. R. Enikeeva S. Yu. Serenko V. D. Komissarov G. A. Tolstikov 《Russian Chemical Bulletin》1991,40(2):280-284
Alkanesulfonic peracids RSO4H effectively oxidize olefins to the corresponding epoxides. The kinetics and mechanism of this reaction are studied. It was shown that both the monomer and dimer form of the peracid act as oxidizing agents. The dependence of the weight constant of the reaction of monomer RSO4H with substituted acyclic olefins on the structure of the latter is described by the Taft equation. A linear correlation is established between log k2 and the inductive constants of the substituents on the oxygen atom in the peracid.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 333–337, February, 1991. 相似文献
918.
V. A. Batanov V. S. Petriv A. O. Radkevich A. L. Telyatnikov A. Yu. Volkov 《International Journal of Infrared and Millimeter Waves》1991,12(7):703-715
High power IR pumping beams self focusing and defocusing in NH3 Raman laser is investigated by numerical methods on the basis of the solution of nonlinear quasioptical equations. The analysis of self focusing have been done for a wide range of parameters of radiation and of active medium. Spatial evolution of the beam configuration have been investigated for different regimes of nonlinear diffraction. Developed model enables to allow exactly for the spectroscopic features of active molecules and may be applied to the analysis of the properties of powerful optically pumped FIR lasers. 相似文献
919.
Exact cylindrically symmetric solutions are obtained for a class of interacting scalar and vector fields in a rotating Godel Universe. We select those with the properties of solitons with smooth decrease of the fields to asymptotics and those with sharp boundaries (droplets). It is shown that only some of the droplets are stable with respect to perturbations that preserve cylindrical symmetry.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 24–27, May, 1991. 相似文献
920.
由于原子簇化合物在催化,生物活性,功能材料等方面所呈现的重要性,使其成为无机和物理化学最重要的研究领域之一。文章中和谱学方法对一些具有混配体的过渡金属簇合物的结构及其两者之间的关系进行. 相似文献