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61.
Let G be a finite group. A complete Sylow product of G is a product of Sylow subgroups of G, one for each prime divisor of |G|. We shall call G a Sylow factorizable group if it is equal to at least one of its complete Sylow products. We prove that if G is a Sylow factorizable group then the
intersection of all complete Sylow products of G is equal to the solvable radical of G. We generalize the concepts and the result to Sylow products which involve an arbitrary subset of the prime divisors of |G|.
Received: 26 January 2005 相似文献
62.
Dan Popovici 《Comptes Rendus Mathematique》2004,338(1):59-64
Let (X,ω) be a compact complex Hermitian manifold, and let T?γ be a d-closed (1,1) almost positive current on X. A variant of Demailly's regularization-of-currents theorem states that T is the weak limit of a sequence of (1,1)-currents Tm with analytic singularities of coefficient 1/m, lying in the same cohomology class as T, whose Lelong numbers converge to those of T, and with a loss of positivity decaying to zero. We prove that if the (1,1)-form γ is assumed to be closed and C∞, the regularizing currents Tm can be chosen such that for a constant C>0 independent of m. To cite this article: D. Popovici, C. R. Acad. Sci. Paris, Ser. I 338 (2004). 相似文献
63.
Wei Jun Liao Xianfeng Chen Fucheng Chen Yuping Chen Yuxing Xia Yingli Chen 《Optics & Laser Technology》2004,36(8):603-606
In this paper, we first report that a new proton source, glutaric acid, has been used to fabricate optical waveguides in Z-cut lithium niobate crystals. The relationship was experimentally established between proton-exchanged (PE) waveguide parameters and fabrication conditions. It is shown that this new organic acid can be used to obtain deep PE waveguides in fast diffusion speed (0.275 μm2/h at 221°C) and with low loss (0.2 dB/cm). It provides an alternative approach for fabricating PE waveguides in lithium niobate substrate. 相似文献
64.
In this paper, we have developed an analytical model to study the temperature distributions in IR optical materials heated by laser pulses. Our model takes into account the two-photon absorption (TPA). The calculations are based on a three-dimensional model of heat diffusion in solids using the integral transform method. We find out the rigorous analytical expression of the thermal field when one considers both one- and two-photon absorption. The model is valid for any laser–solid system whose interaction can be described by the generalized Beer–Lambert law. Specific results are presented for an application of the model to ZnSe sample. We find out that TPA can produce detectable temperature variation. 相似文献
65.
Under the nonresonant case where the carrier frequency of a Gaussian beam deviates from the resonant frequency of a Fabry–Perot etalon, the transmission of a Gaussian beam after incidenting nonnormally on a Fabry–Perot etalon has been investigated. The results show that under the nonresonant case, variations of the peak intensity, the position of the peak intensity and the spot size of the transmitted beam with the input angle behave differently and even with a reversed tendency compared with those obtained under the resonant case. 相似文献
66.
ChunXiaLI YingXiaLI LingBoYU HuaZHANG SiftDongCHU HuaShiGUAN 《中国化学快报》2003,14(8):776-778
A convenient synthetic route was developed for the synthesis of the novel glycolipids: 1,2-di-O-acyl-3-O-(2‘-acylamide-2‘-denxy-ct-D-glucopyranosyl)-sn-glycerols. 10 new compounds of glycolipids with different acyl groups were obtained. 相似文献
67.
Simple Entanglement Measure for Multipartite Pure States 总被引:3,自引:0,他引:3
Feng Pan Feng Pan Feng Pan Dan Liu Guoying Lu J. P. Draayer 《International Journal of Theoretical Physics》2004,43(5):1241-1247
A simple entanglement measure for multipartite pure states is formulated based on the partial entropy of a series of reduced density matrices. Use of the proposed new measure to distinguish disentangled, partially entangled, and maximally entangled multipartite pure states is illustrated. 相似文献
68.
钛酸钾晶须通常是直径和长度在微米量级的无机晶须 ,可用K2 O·nTiO2 表示其组成 ,n =1,2 ,4 ,6 ,8,[1] .六钛酸钾晶须具有耐高温、耐腐蚀、纤维拉伸强度高、导热系数小、红外反射率高 ,硬度低的特点 .在民用及工业方面有很多应用 .如催化剂载体、离子吸附交换材料、高温过滤器、绝热材料、耐摩擦材料等[2~ 5] .钛酸钾纳米线的合成尚未见报道 .我们在用电弧产生的N2 等离子体热解焦油时 ,生成了一种直径 9~ 2 0nm长约几百纳米线 .X射线能谱定量分析表明这种纳米线化学组成为K2 Ti8O15,是一种新的非化学计量化合物 .试验装… 相似文献
69.
Optical characterization of bromo-alkoxyl-substituted copper phthalocyanine derivative thin films 总被引:2,自引:0,他引:2
A series of thin films of copper phthalocyanine derivatives with bromine and alkoxyl substituents [CuPc(OC8H17)4Brm, m=0,1,2,4] were prepared on single-crystal silicon substrates by spin coating. The ellipsometric spectra of the films have been studied on a rotating analyzer–polarizer type of scanning ellipsometer. The optical, dielectric constants and absorption coefficients of the films in 500–800 nm wavelength region were obtained. The results show that the complex refractive index, dielectric constants and absorption coefficient of these thin films are influenced regularly by bromine substituent on conjugated macrocycle. It was found that there are approximately linear relationships between the resonance absorption wavelengths of the films and the average number of bromine atoms substituted on the phthalocyanine ring. 相似文献
70.
KunHuaLIN MaoPingSONG ChenXiaDU QiaoHongZHANG YangJieWU 《中国化学快报》2003,14(7):673-676
The cyclomercurated ferrocenylimines containing heterocyclic ring were prepared by the condensation of cyclomercuration of acylferrocene with the appropriate heterocyclic amine.This procedure provides an efficient method for the synthesis of cyclomerucurated ferrocenylimines containing heterocyclic ring which are difficultly synthesized by the conventional method.The reaction mechanism is proposed. 相似文献