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41.
无衍射光学晶格主要采用函数传递的方式进行数值计算分析,数学模型抽象,程序构建复杂,难以灵活地分析不同光学元件及其缺陷和光路结构对光学晶格物理形成过程的影响。从光路仿真角度出发,提出了一种无衍射光学晶格的分析方法,实现了基础方晶格、最大对称组合基础方晶格、一级稀疏方晶格等典型光学晶格结构的仿真,并验证了光束的无衍射性,说明了该方法的可行性。将该方法应用于光路结构和光学元件特性与光学晶格结构之间的关联分析,有助于探索无衍射二维光学晶格的形成与调控方法,以及潜在应用效果的评估。 相似文献
42.
Evolution from Diffuse Ferroelectric to Relaxor Ferroelectric in Pb1-xBax(Fe1/2Nb1/2)O3 Solid Solutions 下载免费PDF全文
Dielectric and ferroelectric characteristics for Pb1-xBax(Fe1/2Nh/2)O3 (x = 0,0.05,0.1,0.15, and 0.2) ceramics are determined together with their structures. X-ray diffraction (XRD) analysis confirms the solid solutions with the cubic structure. The dielectric nature changes from diffuse ferroelectric to relaxor ferroelectric with increasing x, while the phase transition temperature Tc (or Tm) decreases monotonously. The diffuse ferroelectric phase transition is observed in the solid solutions with 0≤x ≤0.05. For Pbl-xBax(Fe1/2Nb1/2)O3 with 0.1≤ x≤0.2, relaxor ferroelectric behavior is determined, and the Vogel-Fulcher equation is used to describe the relaxor behavior. The 1/ε versus T plots reveal the diffusion dielectric characteristics in both diffuse and relaxor ferroelectrics. 相似文献
43.
Controllable synthesis,characterization,and growth mechanism of hollow Zn_x Cd_(1-x) S spheres generated by a one-step thermal evaporation method 下载免费PDF全文
Novel hollow ZnxCdl xS spheres that are uniform in size are synthesized through the one-step thermal evaporation of a mixture of Zn and CdS powder. From an X-ray diffraction (XRD) study, the hexagonal wurtzite phase of ZnxCdl_xS is verified, and the Zn mole fraction (x) is determined to be 0.09. According to the experimental results, we propose a mechanism for the growth of Zn0.09Cd0.91S hollow spheres. The results of the cathodoluminescence investigation indicate uniform Zn, Cd, and S distribution of alloyed Zn0.09Cd0.91S, instead of separate CdS, ZnS, or nanocrystals of a core- shell structure. To the best of our knowledge, the fabrication of ZnxCd1-xS hollow spheres of this kind by one-step thermal evaporation has never been reported. This work would present a new method of growing and applying hollow spheres on Si substrates, and the discovery of the Zn0.09Cd0.91S hollow spheres would make the investigation of ZnxCd1-xS micro/nanostructures more interesting and intriguing. 相似文献
44.
A novel inorganic-organic hybrid compound, {[Co(dien)]4[0aO4)MoV8(wV10.56MoV10.44)4- O33(OH)3]}'nH20 (1, n = 1, dien = diethylenetriamine), has been synthesized hydrothermally and characterized by single-crystal X-ray diffraction. Compound 1 crystallizes in the triclinic system with a = 11.927(2), b = 13.328(3), c = 19.306(4)A, a = 93.76(3), β = 94.14(3), γ = 109.99(3)°, V= 2863.2(12) A3, space group P1 and Z = 2 at 173 K. The final full-matrix least-squares refinement converged to R = 0.049 for 9621 observed reflections with 1 〉 2σ(I) and wR = 0.139 for all data (9871) and S = 1.073. Crystal structure analysis shows that 1 contains a kind of the first reported mixed-valence and molybdenum-tungsten mixed-distributed e-Keggin structural polyanion capped by four Co(dien) fragments with the main group element P occupying the center site. These results were further confirmed by energy-dispersive X-ray spectroscopy (EDS), X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, Thermogravimetry (TG) and X-ray photoelectron spectroscopy (XPS) analyses. 相似文献
45.
Four novel transitional metal complexes with 3-(4-pyridly)-4-phenyl-5-sulfhydryl- 1,2,4- triazole (HL1) and 3-(3-pyridly)-4-phenyl-5-sulfhydryl-l,2,4-triazole (HLz) were synthesized and characterized by elemental analysis, IR and X-ray diffraction. Complexes 1, 3 and 4 have two-dimensional (2-D) neutral rhombohedral grid with a (4, 4) topology. In 1, 3 and 4, all the metal ions are six-coordinated to four nitrogen atoms of four distinct ligands and two O atoms from water molecules. Complex 2 has tetranuclear CuaCI4 units which are interconnected by four desulfuri- zation ligands (L1-S) via Cu-N bonds to form a 2-D layer with (4,4) topology. 相似文献
46.
A new sandwiched polyoxometalate [HK11Cd4Cl2(PW9034)2]·18H2O (1), incor- porating a unique hybrid tetranuclear cadmium cluster (abbreviated to {Cd4}) with two trivacant polyanions [B-α-PW9O34]9-, has been hydrothermally synthesized and structurally characterized by elemental analyses, IR spectroscopy, UV-vis, and single-crystal X-ray diffraction analysis. Crystal data for 1: monoclinic, space group C2/c, a = 19.2997(4), b = 13.8014(3), c = 31.9819(8) A, β = 102.764(2)°, V= 8308.3(3) A3, Z = 4, P2O86Cl2K11Cd4W18H37, Mr = 5735.13, Dc = 4.584 mg-mm-3, F(000) = 10084, μ = 26.579 mm-1, the final R = 0.0378 and wR = 0.0989 for 6558 observed reflections (I〉 2σ(I)). X-ray crystallographic study shows that the molecular structure of 1 contains four cadmium atoms. Two CdO6 distorted octahedra and two CdOsC1 distorted octahedra combine with each other in turn via edge-sharing, resulting in a regular rhomb-like cluster sandwiched between two {B-a-PW9034} units. Further, the sandwich-type polyoxoanions were connected by K+ ions to form a complicated 3-D open-framework through connecting with each terminal O atom of the [Cd4C12(PW9O34)2]12- polyoxoanions. In addition, compound 1 exhibits photoluminescence property at room temperature and the band gap can be assessed at 3.25 eV. 相似文献
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49.
针对光栅衍射实验中如何保证平行光正入射光栅表面这一难点,总结出一种在实验教学简单可行、易于学生理解的操作方法。这种实验方法,既包含了分光计调节的基本要求,又能让学生比较容易掌握和理解光栅的衍射理论,提高了实验效率。 相似文献
50.
MEI Chong-Zhen WANG Hai-Rong XIONG Han-Lin MENG Rui-Jing SHAN Wen-Wen LI Hai-Hua 《结构化学》2014,(4):563-568
A new coordination polymer [Ni(L)(m-bix)(H2O)]n (1, H2L = 5-iodo-isophthalic acid, m-bix=1,3-bis(imidazol-1-ylmethyl)-benzene) has been synthesized by the hydrothermal method and characterized by IR, elemental analysis, powder XRD and single-crystal X-ray analysis. The crystal is of triclinic, space group Pī with a = 9.1638(3), b = 10.2319(3), c = 13.2463(4) ?, α = 80.1710(10), β = 83.671(2), γ = 70.3790(10)o,C22H19NiIN4O5, Mr = 605.02, V = 1150.85(6) ?3, Dc = 1.746 g/cm3, F(000) = 600, μ = 2.225 mm-1, S = 1.045 and Z = 2. The final R = 0.0388 and wR = 0.1257 for 5089 observed reflections with I 〉 2σ(I). In the title complex, the M and P layers are arranged alternately to give a double-layer structure by the symmetry related hydrogen bonds, and these double-layers are further joined together to achieve a 2D supramolecular architecture through I···π interaction involving iodine atoms and imidazole rings. The thermal stability of the title complex was studied by thermal gravimetric (TG) and differential thermal analysis (DTA). 相似文献