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81.
The crystal and molecular structure of the complex containing cobalt-carbon and iron-sulfur cluster cores, (μ-p-CH3C6H4C2S) (μ-n-C3H7S)Fe2(CO)6Co2(CO)6, has been determined by X-ray diffraction method. The crystals are triclinic, space group P&1bar;, with a — 9.139(2), b=9.610(1), c-17.183(2) Å, α = 84.36(1), β-89.45(1), γ=88.15(1)°, V-1501.0 Å3; Z=2, Dc=1.74 g/cm3. R=0.072, Rw=0.081. The results of the structure determination show a cobalt-carbon cluster core formed through the reaction of (μ-p-CH3C6H4C2S)(μ-n-C3H7S)Fe2(CO)6 with Co2(CO)8. In the cobalt-carbon cluster core, the bond length of the original C≡C lengthened to 1.324 Å which is close to the typical value of carbon-carbon double bond. The groups connecting the carbons of the cluster core are in cis position and lie on the opposite side of cobalt atoms. In this complex, the conformation of —SC3H7 is e-type, while that of —SC2C6H4CH3 is a-type. 相似文献
82.
In this paper, we have developed a load-bearing outer skin for antennas, which is termed a composite smart structure (CSS). The CSS is a multilayer composite sandwich structure in which antenna layers are inserted. A direct-feed stacked patch antenna is considered. A design procedure including the structure design, material selection, and design of antenna elements in order to obtain high electric and mechanical performances is presented. An optimized honeycomb thickness is selected for efficient radiation and impedance characteristics. High gain conditions can be obtained by placing the outer facesheet in the resonance position, which is at about a half wavelength distance from the ground plane. The measured electrical performances show that the CSS has a great bandwidth (over 10%) and a higher gain than an antenna without a facesheet and has excellent mechanical performances, owing to the composite laminates and honeycomb cores. The CSS concept can be extended to give a useful guide for manufacturers of structural body panels and for antenna designers. 相似文献
83.
In this paper, an interior point cutting plane method (IPCPM)is applied to solve optimal power flow (OPF) problems. Comparedwith the simplex cutting plane method (SCPM), the IPCPM is simpler,and efficient because of its polynomial-time characteristic.Issues in implementing IPCPM for OPF problems are addressed,including (1) how to generate cutting planes without using thesimplex tableau, (2) how to identify the basis variables inIPCPM, and (3) how to generate mixed integer cutting planes.The calculation speed of the proposed algorithm is further enhancedby utilizing the sparsity features of the OPF formulation. Numericalsimulations on IEEE 14-300-bus test systems have shown thatthe proposed method is effective. 相似文献
84.
85.
Low-loss and rugged distal tips for CO2 laser have been proposed and fabricated based on a commercially available stainless steel (St) pipe. A method of smoothening the inner surface of the St pipe with a rough inner surface is put forward. Fabrication parameters, transmission properties, and mechanical strength of the cyclic olefin polymer-coated silver hollow St distal tip are experimentally discussed. 相似文献
86.
87.
Yang Ruike Wu Zhensen You Jinguang 《International Journal of Infrared and Millimeter Waves》2003,24(8):1383-1392
The influence of sand and dust storms on modern MMW and satellite communication systems reliability have been paid more attention to. The attenuations induced by sand and dust storms are estimated by means of Mie-theory and Rayleigh approximation, in the case of the tenuous distribution of particles. With the particle density increasing, however, these method become inadequate, the multiple scattering effects then become dominant for attenuation estimation. The attenuations considering multiple scattering effects are estimated by Monte-Carlo and four fluxes method at horizontal paths. At slant paths, based on multi-layer media model, the attenuations considering multiple scattering effects are calculated by layered Monte-Carlo method at 100, 37, 24, and 14GHz. It is shown that the multiple scattering effects should be considered at the attenuation prediction in the sand and dust storm, which the visibility is about 0.5km and smaller than 0.5km and frequency is about 20GHz. Above 30GHz, the multiple scattering effects due to sand and dust particles should be considered, as visibility is about 1km and smaller than 1km at slant paths. 相似文献
88.
C.H Chung S.D KimH.J Kim F.O AdurodijaK.H Yoon J Song 《Solid State Communications》2003,126(4):185-190
The dependence of structural properties and surface morphology of Cu-In alloy layers on the composition and sputtering deposition sequence were investigated by X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy. The properties of the co-sputtered alloy layers changed abruptly around the composition boundary when the Cu/In ratio reached 1/2. This can be explained by the effective heat of formation (EHF) model, which has been used to predict the sequence of phase formation for metal diffusion couples. The use of a co-sputtered alloy layer with a high In concentration was not suitable for fabricating solar cells, because the film had a very rough morphology due to large In islands formed on the CuIn2 phase. However, it was possible to minimize this phase by In sputtering followed by co-sputtering with a Cu/In ratio of 1 (Cu-In/In/Glass). This permitted the fabrication of a homogeneous Cu-In alloy layer, which was not possible through the simple co-sputtering. 相似文献
89.
Bi12TiO20纳米粉体的制备及其光吸收特性研究 总被引:3,自引:0,他引:3
以钛酸四丁酯和硝酸铋为原料 ,利用化学溶液分解法制备了Bi12 TiO2 0 纳米多晶粉体 .采用XRD和TEM对其结构和形貌进行了表征 .结合热重 差热 (TG DTA)分析 ,探讨了Bi12 TiO2 0 晶相的形成机理 .通过UV Vis漫反射谱的测定 ,研究了Bi12 TiO2 0 纳米晶粉体的光吸收特性 .结果显示 ,从组成为化学计量比的前驱液中可以很容易制得纯Bi12 TiO2 0 纳米晶粉体 ,该Bi12 TiO2 0 纳米晶粉体呈现了在很宽的波长范围内 (5 6 0~ 385nm )对光的吸收的特性 . 相似文献
90.