高精度大功率双向可调电源设计

为满足ITER传感器测试平台对电源高稳态精度、高压及大电流性能需求，通过H桥级联载波移相方式对大功率电源进行设计，并进行谐波分析，有效地提高变流器等效开关频率，改善输出波形。经实验验证，取得较好效果。     

Phase-Measuring Algorithms to Suppress Spatially Nonuniform Phase Modulation in a Two-Beam Interferometer

Phase modulation of presently used phase-shifting interferometers is assumed to be spatially uniform across the observing aperture. However, calibration errors or the configuration of an interferometer can cause a spatial nonuniformity in the phase modulation. Spatial nonuniformity causes a significant error in the measured phase when the phase modulator has nonlinear sensitivity. An even-order nonlinearity in the phase modulation in particular contributes to the errors. Lowest-order errors can be suppressed by adding a new symmetry to the sampling functions of the phase-shifting algorithm, however the algorithm suffers from large random noise. The random noise is shown to be decreased substantially by applying one more sampled frame to the algorithm. We derive new seven-sample and eight-sample algorithms that can compensate for a nonuniform phase shift and has much less random noise than the previous algorithm we proposed.     

星系哈勃红移的非多普勒效应解释

分析了多普勒效应在解释星系哈勃红移现象时,星系际光传播过程存在的能量不守恒和宇宙膨胀时空不平权两大问题;提出了＂时空物质属性＂的3个基本假设;最后阐述了星系哈勃红移的非多普勒效应解释。     

辊型CCD检测法中轧辊轴线偏移的补偿

根据激光线阵CCD检测技术原理,提出一种快速、高准确度的轧辊辊型检测方法,阐述了系统组成与检测过程.针对辊型检测过程中易出现的轴线偏移现象,从垂直检测平面和平行检测平面两个方向采取补偿措施,有效地提高了系统检测准确度,同时检测系统对CCD信号进行处理时,采用浮动阈值法,有效降低噪音对CCD成像质量的影响,保证了系统的分...     

Theoretical Study of the Interactions Between Borthiin and Fluorinated Borthiins with Difluorine

The nature of borthiin and fluorinated borthiin interactions with difluorine was studied with ab initio calculations. The interaction energies were calculated at the B3LYP/6-311+G(d,p) level. Vibrational and AIM analyses of the complexes indicate that the variation of densities correlates well with the obtained interaction energies. Also, the nucleus independent chemical shift (NICS) values have been used for studying aromaticity in species. These values suggest that aromaticity increases in complexes.     

NMR Study of the Hydrogen Bonding of Sterically Hindered Phenols with Alicyclic Ethers and Pyridine

In a preliminary report¹ it was shown that the hydrogen-bond chemical shift, δ_AB, correlates with the change in enthalpy, δH, in the interaction of chloroform with a series of closely related oxygen and nitrogen bases. In this communication, we report the hydrogen bonding parameters for the interaction in cyclohexane medium between 2,4,6-tri-t-butylphenol and tetrahydrofuran, tetrahydropyran and pyridine, and between 2,6-di-1-adamantyl-4-t-butylphenol and pyridine. There is correlation between the δ_AB and δ_AE for the same proton donor (2,4,6-tri-t-butylphenol) and the closely related alicyclic bases, and for the same base (pyridine) and the two closely related sterically hindered phenols. The temperature dependence of the δ_AB in these systems is also reported.     

Effect of Linewidth Enhancement Factor on Doppler Beat Waveform Obtained from a Self-Mixing Laser Diode

The asymmetry and fringe inclination of the sawtooth-like waveform observed in the self-mixing signal obtained from a semiconductor laser with optical feedback enable the direction discrimination of line-of-sight motion of external target surfaces. We investigated the effects of linewidth enhancement factor and feedback strength on the asymmetry and the direction of fringe inclination of the signal by numerical simulations. For the first time, we show that direction of the fringe inclination is determined not only by the direction of the target motion but also by the value of the linewidth enhancement factor.     

Insertion of O-H Bond of Rh（ Ⅱ）-methylene Carbene into Alcohols： A Stepwise Mechanism More Plausible than a Concerted Mechanism

IntroductionDirhodium(Ⅱ) complexes can catalyze the valua-ble dirhodium(Ⅱ) reactions ofα-diazo carbonyl com-pounds[1—7]. The generated Rh(Ⅱ) carbene interme-diates can subsequently undergo synthetically diversetransformations, including ylide formati