Study on EDFA Gain Tilt and Nonlinear Distortion in an AM-VSB CATV Optical Fiber Transmission System

The gain tilt of the erbium-doped fiber amplifier (EDFA) and the nonlinear distortion in an AM-VSB CATV optical fiber transmission system with a cascade of EDFAs are analyzed. It demonstrates that the nonlinear distortion induced by the light source and the EDFA would be counteracted each other to a certain degree as long as the EDFA has a negative gain tilt. As a result,an optimal EDFA negative gain tilt is suggested as a solution to self-compensation of the nonlinear distortion.     

Spectroscopic analysis of asymmetric top free radicals——Application to pure rotational spectra of NO_2 in the ground vibronic state

Several key problems involved in the analyses of spectra of asymmetric top molecules, i.e., the effective Hamiltonian, the representation and basis vector, identification of energy levels, the selection rules, the relative intensity, and Zeeman tuning rate, were elucidated systematically. Introducing the high-order centrifugal distortion terms into the effective Hamiltonian, the precision for calculation has been improved substantially, which allows us to analyze the high-lying rotational transitions. A global analysis of all available spectra of 14N16O2 in the ground vibronic state has been made to obtain a set of molecular constants of 14N16O2 in the ground vibronic state which is the most precise and extensive so far. Using the improved parameters, some FIR LMR lines left unassigned hitherto have been identified successfully.     

关于某些调和函数

用H表示形如f(z)=h(z) g(z)的调和函数族,其中h和g是单位圆盘内的解析函数.本文考虑H的三类子族函数.其中的两族为PH(α)=f∶Ref(z)z≥α和NH(α)=f∶Ref(z)θz≥θα,其中0≤α<1和θ=argz.本文得到了函数f属于其中一族的一个充分必要条件,并且获得了一些系数不等式和偏差定理.     

拟共形映照的双曲面积偏差估计

The distortion property of hyperbolic area of planar quasiconformal mappings is studied in this paper.In the case of radial quasiconformal mappings and angular deformed quasiconformal mappings their hyperbolic area distortions are estimated quite sharply.The result can be applied to judge whether the hyperbolic area of a planar subset is explodable.     

1.5MeV LIA脉冲功率系统

本文简要介绍了1.5MeV LIA脉冲功率系统的结构、组成和设计思想;给出了开关运行参数和确定开关时间抖动指标的方法、闭环系统的总抖动对加速电压相对变化的影响、脉冲功率系统各段输出波形和电压幅度的调制关系;测量结果表明,1.5MeV LIA的运行功率和时间同步满足总体设计要求。     

基于Zernike多项式的波前传感器的光子受限的研究

应用基于Zernike多项式的波前探测和重构方法2,利用蒙特卡罗法,可求出探测器在不同的光子数下,其探测精度的变化。文章还给出了由不同的探测器组成的传感器,探测星等的变化情况。     

二次谐波中大相位失谐下入射啁啾脉冲对相位的影响

讨论了在大相位失谐下,基波为频率啁啾脉冲的二次谐波产生过程,结果表明选取合适的啁啾参量可以使二次谐波的光强提高,但同时会使其波形和相位发生变化.三波相位的畸变主要取决于入射的基波啁啾脉冲,而与相位匹配的失谐量关系不大.     

Single crystal EPR studies of Mn(II) doped into zinc ammonium phosphate hexahydrate (ZnNH4PO4·6H2O): A case of interstitial site for bio-mineral analogue

Single crystal EPR studies of Mn(II)-doped zinc ammonium phosphate hexahydrate (ZnNH₄PC₄·6H₂O) have been reinvestigated at room temperature. Single crystal rotations along the three orthogonal axes indicate that the spin Hamiltonian parameters for the interstitial site are:g _xx = 1.966,g _yy = 1.972,g _zz = 1.976;D _xx = -12.28 mT,D _yy = -2.09 mT andD _zz = 14.37 mT;A _xx = 9.06 mT,A _yy = 9.06 mT andA _zz = 11.09 mT;a = -0.11 mT. These parameters differ considerably from the previous report of Chand and Agarwal and indicate the orthorhombic nature of the paramagnetic impurity. The impurity is found to enter the lattice interstitially, in contrast to earlier prediction of substitutional position. The percentage covalency of the Mn-0 bond has been estimated.     

DISTORTION OF CRYSTAL LATTICE IN NANOCRYSTALLINE Fe_2O_3

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摄像机图像相对畸变系数的计算

主要论述了摄像机相对畸变系数的计算方法。该计算方法包含了三个计算过程 :第一 ,规定了每个像素理想像高的坐标表示法 ;第二 ,在坐标系中确定理想像高相对畸变系数的一般表示 ;第三 ,利用光学系统的对称性 ,经过适当的坐标变换 ,逐点计算出整幅画面实际像高的坐标表示。给出了计算步骤 ,并通过编程可获得摄像机的四个相对畸变系数的文件。