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51.
52.
Zhicheng Xiao Ying Li Dongling Ma Linda S. Schadler Yvonne A. Akpalu 《Journal of Polymer Science.Polymer Physics》2006,44(7):1084-1095
Small‐angle light scattering (SALS) measurements were used to study the structure of titanium dioxide (TiO2)/low‐density polyethylene (LDPE) nanocomposites. The results showed that the scattering from LDPE crystalline structures and the scattering from TiO2 nanoparticles can be resolved and separated. It is shown that the independent effects of crystallization conditions and the presence of nanoparticle aggregates on the spherulitic structure of the LDPE matrix can be determined by analyzing the scattering patterns using the methods proposed. From the SALS results, we conclude that the nanoparticle surface chemistry affects both nucleation of spherulites and their structure particularly under rapid cooling conditions. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1084–1095, 2006 相似文献
53.
We study the existence of positive solutions to the operator equation Lx = Nx, where L is a linear Fredholm mapping of index zero and N is a nonlinear operator. Using the properties of cones in Banach spaces and Leray-Schauder degree for completely continuous
operators, k-set contractions and condensing mappings, we obtain some refinements of the results established in [3] and [14].
Received: 9 July 2005; revised: 12 January 2006 相似文献
54.
物理插图能起到形象地再现物理情景,辅助解释物理原理的作用.现行人教版物理第二册(必修加选修),第十章“机械波”第一节的知识“波的形成和传播”是该章的重点,本节插图10-5“横波的形成”又是该节的教学重点.这幅插图用得好,直接为后面的波的图像教学及用图像解决问题打下坚实的基础. 相似文献
55.
激光感生碰撞能量转移的四能级理论模型 总被引:6,自引:2,他引:4
首次考虑了两个中间态对激光感生碰撞能量转移的影响,发展了激光感生碰撞能量转移的四能级理论模型,推导出态振幅的运动方程,并给出碰撞截面的近似表达式,通过对Eu-Sr和Cs-Sr系统的数值计算表明,当频率差│ω21│大小和│ω43│可以相比时,利用三能级近似理论就难以获得令人满意的计算结果,而四能级理论模型则适合于任何情况下的激光感生碰能量转移。 相似文献
56.
Let (E, ¦·¦) be a uniformly convex Banach space with the modulus of uniform convexity of power type. Let be the convolution of the distribution of a random series inE with independent one-dimensional components and an arbitrary probability measure onE. Under some assumptions about the components and the smoothness of the norm we show that there exists a constant such that |{·<t}–{·+r<t}|r
q
, whereq depends on the properties of the norm. We specify it in the case ofL
spaces, >1. 相似文献
57.
Paweł Grochulski Zdzisław Wawrzak Zdzisław Gałdecki Antoinette Viger Suzy Coustal 《Journal of chemical crystallography》1990,20(5):429-432
The crystal structure of 18-cyanoprogesterone was determined by X-ray diffraction methods:P212121
a=7.436(2),b=11.322(2),c=22.642(2) Å. The structure was solved usingShelx-86. Final conventionalR=0.054.R
w
=0.051 for 1841 reflections. TheA ring has an intermediate sofa-half-chair conformation with asymmetry parameters C
s
/1
=11.0, C
2
3,4
=14.9. The steroid skeleton exhibits a flattening of theA ring relative to the rest of the molecule. The progesterone side chain has a typical conformation, and the C16-C17-C20-O20 torsion angle is –19.0(6)°. 相似文献
58.
The picosecond degenerate four-wave mixing reflectivity of semi-insulating gallium arsenide at 1.06 m is calculated in this paper. The dependence of the reflectivity on the pump and signal fluences is measured. Reflectivities of more than one are possible. The Fourier components of the excited-carrier densities are calculated as a function of the pump fluence. The wavefront-correction property of this reflectivity is demonstrated with a lens group in the signal beam. 相似文献
59.
The dynamical system approach is applied to the study of dynamics of multidimensional cosmological models with topology FRW ×T
D (D-dimensional torus) in the presence of high-temperature quantum effects. The stability methods developed in the paper of Szydowski (Gen. Rel. Grav.,20, 221, 1988) are used in the analysis of typical states of the metric in the neighborhood of singularities and for large time values. The problems of dynamical dimensional reduction, structure of singularities, isotropization, etc., are discussed in this context. 相似文献
60.
It is well-known thatn points not belonging to a hyperplane determine at leastn hyperplanes. The possible configurations of hyperplanes in the case when the number of hyperplanes is equal ton are known, too. In this paper we obtain these results by means of Hall's representatives theorem. The setting is that of a finite geometry. 相似文献