双反射镜式光电经纬仪测角误差的分析(轴系部分)

双反射镜式光电经纬仪由于采用了反射镜跟踪头,轴系误差对测角精度的影响不同于典型光电经纬仪。本文从建立经纬仪三维直角坐标系入手,建立了该类型经纬仪轴系误差引起测角误差的数学模型,为精度分析和误差修正提供了依据。     

Theoretical kinetic study on the decomposition of 1,5‐diaminotetrazole

1,5‐Daminotetrazole (DAT) is of much interest because of the practical significance and the diversity of characteristics. The study on the decomposition pathway and the kinetics of DAT has been performed based on the quantum chemistry theory. The minimum energy path (MEP) calculation has shown that NH₂N₃ and NH₂CN are the initially detected products of DAT. And the structures of reactant, products and transition state were optimized with MP2 methods using 6‐311G** basis sets, and the energies were refined using CCSD(T)/6‐311G** levels of theory. The calculated rate constants were obtained using the conventional transition‐state theory (TST) and the canonical variational transition‐state theory (CVT) methods. The calculation results indicated that the energy barrier of decomposition reaction is 47.98 kcal mol^?1 and the variational effect is small. In addition, the rate constants and the Arrhenius experience formula of DAT decomposition have been obtained between 200 and 2500 K temperature regions. The fitted three‐parameter expressions calculated using the TST and CVT methods are (TST) and (CVT). This work may provide the theoretical support for further experimental synthesis and testing. Copyright © 2015 John Wiley & Sons, Ltd.     

超临界CO_2在内螺纹管内换热特性研究

建立了外径为3 mm的内螺纹管三维实体模型,使用Fluent软件研究了在不同的进口雷诺数和操作压力下超临界二氧化碳在水平内螺纹管内的流动与传热特性。研究表明:不同截面局部换热系数和相同流体局部平均温度下的局部换热系数均随着冷却压力的增大而增大;相同流体局部平均温度下的局部换热系数随着进口雷诺数的增加而增大;不同冷却压力和进口雷诺数下,流体局部平均温度越接近超临界二氧化碳的临界点温度,局部换热系数也就越大。     

非近邻跳跃对扶手椅型石墨烯纳米带电子结构的影响

根据π电子的紧束缚模型,将电子的次近邻和第三近邻跳跃能考虑在内,得到扶手椅型石墨烯纳米带（AGRNs）能带结构的解析解.讨论了由次近邻和第三近邻电子跳跃引起的能带和能隙变化,发现次近邻和第三近邻跳跃分别对带隙产生增大和减小的影响. 比较了边界弛豫与非近邻跳跃之间的互相竞争关系. 当纳米带的宽度n为奇数时,二维石墨面的紧束缚模型中所固有的van Hove奇异性表现为AGRNs中的无色散带. 当AGRNs宽度增加时,能谱趋向于二维石墨烯时的能谱结构. 关键词： 扶手椅型石墨烯纳米带 非近邻跳跃 边界弛豫 电子结构     

Optical properties of PMN–PT thin films prepared using pulsed laser deposition

(1 ? x)Pb(Mg_1/3Nb_2/3)O₃–xPbTiO₃ (PMN–PT) thin films have been deposited on quartz substrates using pulsed laser deposition (PLD). Crystalline microstructure of the deposited PMN–PT thin films has been investigated with X-ray diffraction (XRD). Optical transmission spectroscopy and Raman spectroscopy are used to characterize optical properties of the deposited PMN–PT thin films. The results show that the PMN–PT thin films of perovskite structure have been formed, and the crystalline and optical properties of the PMN–PT thin films can be improved as increasing the annealing temperature to 750 °C, but further increasing the annealing temperature to 950 °C may lead to a degradation of the crystallinity and the optical properties of the PMN–PT thin films. In addition, a weak second harmonic intensity (SHG) has been observed for the PMN–PT thin film formed at the optimum annealing temperature of 750 °C according to Maker fringe method. All these suggest that the annealing temperature has significant effect on the structural and optical properties of the PMN–PT thin films.     

Atom waveguide and 1D optical lattice using a two-color evanescent light field around an optical micro/nano-fiber

We propose a two-color scheme of atom waveguides and one-dimensional （1D） optical lattices using evanescent wave fields of different transverse modes around an optical micro/nano-fiber. The atom guide potential can be produced when the optical fiber carries a red-detuned light with TE01 mode and a blue-detuned light with HEll mode, and the 1D optical lattice potential can be produced when the red-detuned light is transformed to the superposition of the TE01 mode and HE11 mode. The two trapping potentials can be transformed to each other for accurately controlling mode transformation for the red-detuned light. This might provide a new approach to realize flexible transition between the guiding and trapping states of atoms.     

Effect of the ratio of transition dipole moments on few-cycle pulse propagation

Propagation of a few-cycle laser pulses in a dense V-type three-level atomic medium is investigated based on full-wave Maxwell-Bloch equations by taking the near dipole-dipole (NDD) interaction into account. We find that the ratio, γ, of the transition dipole moments has strong influence on the time evolution and split of the pulse: when γ≤ 1, the NDD interaction delays propagation and split of the pulse, and this phenomenon is more obvious when the value of γ is smaller; when γ = 2, the NDD interaction accelerates propagation and split of the pulse.     

Na或Cu掺杂对Si/NiO异质结的光电性能影响

利用磁控溅射方法制备了引入Na或Cu元素前后Si/NiO异质结。实验结果表明,Na元素引入后的Si/NiO：Na异质结的整流特性最佳。此时,Si/NiO：Na异质结光学透过率可以达到70%,这可能是由于Si/NiO：Na异质结的结晶质量较优、薄膜内缺陷少所致。Si/NiO：Na异质结I-V曲线的拟合结果显示界面态状态也会影响其整流特性。而Si/NiO和Si/NiO：Cu异质结都没能获得较好的整流特性,可能是薄膜内缺陷增多所致。这一结论得到了XRD、SEM、AFM和UV结果的支持。     

用多面体测试分度误差研究

采用多面体和光电平行光管测试圆刻机分度误差，比较了１２、３６、７２面体的测试特点，从数据分析中可找到一些造成误差的因素