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把一个由GaAs光电导开关和激光腔中的普克尔盒组成的正反馈回路,用于YAG激光器中,选单纵模和调Q,获得了稳定可靠的单纵模调Q脉冲. 相似文献
54.
合成了两个由胍盐(G)和4,4’—苯醚二磺酸(PEDS)为主体框架所形成的主— 客体包合物,分别为[(CH6N3)]2[(C12H8O7S2)]·MeOH·2(H20)(1)和[(CH6N3)]2[ (C12H8O7S2)]·(C10H8)(2).两个化合物都是以P—1空间群结晶,晶胞参数分别为 :1a=0.7509(4)nm,b=1.2113(6)nm,c=1.5936(8)nm,a=102.636(10)° ,β=102.703(11)°,γ=91.318(10)°;2a=0.75409(3)nm,b=1.21584 (5)nm,c=3.09376(14)nm,a=81.506(2)°,β=89.669(2)°,γ=88. 890(2)°。在这两个晶体结构中,G和PEDS通过氢键形成了双夹层—双柱子的主体 框架,客体分子被包合在平行于a轴方向的晶格空间.这种双夹层—双柱子的主体 框架在由胍盐(G)和有机二磺酸(S)体系所形成的、具有通道结构的主体框架中是较 为少见的. 相似文献
55.
Natalie Smirnova Anna Eremenko Vladimir Gayvoronskij Irina Petrik Yuriy Gnatyuk Galina Krylova Andrey Korchev Alexej Chuiko 《Journal of Sol-Gel Science and Technology》2004,32(1-3):357-362
Titania and silica-based porous coatings have been produced via sol–gel route in the presence of pore-creating agents PEG and viscous solvent -terpineol, or template agents CTAB, as well as triblock copolimer Pluronic P123. Porous titania films were characterised by HR TEM, UV-Vis, XRD, ellipsometry, ARS methods. The dispersion of the refractive index, the porosity (32–39%) and the thickness of the samples were estimated by integrating sphere transmission and reflection spectra with 3D angular resolved light scattering. The catalytic activity of mesoporous TiO2 and TiO2/ZrO2 as well as SiO2-benzophenone films in the process of CrVI to CrIII and Ag+ to Ag0 photoreduction have been studied. 相似文献
56.
NG S. K.; CAINES P. E.; CHEN H. F. 《IMA Journal of Mathematical Control and Information》1984,1(2):129-140
Following the procedure described by Elworthy (1982) and Ikeda& Watanabe (1981) we construct the solution of stochasticdifferential equations (SDEs) in manifolds. We take such SDEsto describe parametrized completely observed stochastic systemsand manifold-valued state processes. The likelihood functionfor the system parameter is computed by two methods: the firstapplies to the case of parallelizable manifolds; the secondapplies to the general case, here the solution of the systemSDE is constructed in the orthonormal frame bundle of the manifold.Two examples are given. 相似文献
57.
1 INTRODUCTION Much attention has been paid to 1D, 2D and 3D coordination polymers because they can meet the need of functional materials with desired structures and properties[1~5]. One strategy in the design and synthesis of coordination architectures is the buil- ding-block approach. Commonly, bi- or multidentate organic ligands containing N[6, 7] or O[8, 9] atoms have ever been used in the construction. In our cur- rent work, we have selected melamine ligand as the main building bl… 相似文献
58.
具有中孔结构的SO4^2—/Zr—HMS型固体超强酸的合成和结构表征 总被引:6,自引:0,他引:6
用TEOS-Zr-HAD-H2O-Etheanol体系合成了Zr-HAD的中孔分子筛,脱除模板剂后用0.5mol/L硫酸处理和550℃高温焙烧3h,制得一种中孔SO4^2-/Zr-HAD超强酸催化剂,采用XRD对其结构进行表征,用指示剂法,TG和NH3-TPD对其酸性进行了表征。结果表明,经过一系列处理后制得的SO4^2-/Zr-HAD催化剂具备HMS中孔分子筛的结构特征,其酸强度可达H0=-13.75,在锆及SO4^2-含量远远低于SO4^2-/ZrO2的条件下,SO4^2-/Zr-HAD催化剂对于苯酐和正丁醇酯化反应的活性仍高于SO4^2-/ZrO2催化剂。 相似文献
59.
The space groups of 244 crystal structures originally reported as P-1 are revised to space groups of higher symmetry. The largest number involves revisions to P2/c and C2/c. 相似文献
60.
NG Seik Weng 《结构化学》2005,24(1)
The space group of [(H2O)(C3H4N2)(O2CCH=CHCO2Zn)]n, which was originally described in the acentric Pc space group (Liu et al., Chin. J. Struct. Chem. 2004, 23, 160~163), is re-described in the centric P21/c space group.The crystal structure of (H2O)(C3H4N2)O2C-CH=CHCO2Zn was refined in the acentric Pc space group on 266 variables to R = 0.037 for the 1926 of the 2067 obeying the I > 2σ criterion[1]. The structure is better described in the centric P21/c space group (Table 1) as the two indepen-dent formula units are related by a center of symmetry. The 21 screw axis is must be pre-sent, as noted from the systematically absent 0k0 (k = 2n + 1) reflections in the 3302 reflections that were simulated[2, 3] from the published cell dimensions and atomic coordinates. Crystallo-graphica[4] estimates the hemisphere of reflections to be 3302, so that only a little more than the minimum monoclinic data must have been collec-ted in the study. A revision from Pc to P21/c is not particularly common[5] as the P21/c space group is uniquely determined from systematic absences. The polymeric chain propagates linearly along the c-axis of the unit cell (Fig. 1). 相似文献