一种消除LED显示屏动态假轮廓的脉宽调制法

针对LED显示屏播放运动画面时的动态假轮廓问题,提出了集中式门控脉宽调制法.该方法在原有门控脉宽调制技术的基础上,将PWM周期中的小数场固定于周期的中间,然后计算整数权重位对应的子场数并将其紧邻小数场实现.分析和实验表明,集中式脉宽调制法具有与线性PWM相似的点亮时间函数,能够将任意两灰度级间DFC指标的均值从GPWM方式下的0.6降到0.2以下.在有效消除DFC的同时又保持了GPWM的高刷新频率与高灰度级,从而明显改善图像的显示质量.同时算法实现简单,不需要额外的硬件支持.     

Reverse detection for spectral width improvements in spatially encoded dimensions of ultrafast two‐dimensional NMR spectra

Recently, the spatially encoded technique has been broadly used in the fast analyses of chemical systems and real‐time detections of chemical reactions. In spatially encoded ultrafast 2D spectra, spectral widths and resolution in spatially encoded dimensions are contradictive, leading to the risk of insufficient spectral widths when providing satisfactory resolution values for all resonances. Here, a method named as reverse detection is proposed to improve the spectral width in the spatially encoded dimension. Experimental results show that spectral width improvements are at least twofold with reverse detection solely, and more improvements can be expected along with the gradient‐controlled folding method. The proposed method can be applied to almost any spatially encoded scheme with echo planar spectroscopic imaging—like detection module and may promote wide applications of ultrafast 2D spectroscopy techniques in chemical analyses. Copyright © 2014 John Wiley & Sons, Ltd.     

Electrical characterization and modeling of Au/MEH-PPV/porous n+-GaAs/n+-GaAs heterojunction in direct and alternating current mode

Assembled heterojunction was fabricated by spin-coating poly[2-methoxy-5-(2′-ethyl-hexyloxy)-1,4-phenylene-vinylene)] (MEH-PPV) thin layers on straight and porous n⁺-GaAs substrates. The current–voltage and capacitance–voltage studies have shown an abrupt junction behavior with current conduction governed by SCLC and thermionic modes. Andersons' rules were used to determine depletion width and balance bands discontinuities for both heterojunctions. Capacitance and conductance vs. frequency techniques were used to evaluate the density of interface states. Density values obtained from both techniques were in a good agreement.     

氧-17核磁共振测定的几点讨论

讨论了准确测定氧－１７核磁共振参数的影响因素与实验技巧，并测定了一系列水样的氧－１７核磁共振参数。     

Total cross-section corresponding to the differential cross-section of lindhard,nielsen and scharff

An exact expression is presented for the total cross-section associated with the Winterbon, Sigmund and Sanders version of the Lindhard, Nielsen and Scharff differential cross-section for heavy ion-atom scattering. A series expansion form of the same quantity is also given.     

光脉冲在负色散克尔介质中传输的时空耦合特性

本文综合考虑了在(3+1)维负色散介质中Kerr效应、衍射、色散对光脉冲传输的影响,用变分原理和数值计算的方法对带啁啾高斯光束的传输特性进行了研究,讨论了非线性时空耦合参数,初始束宽、脉宽、散聚特性对时空“自聚焦”特性的影响,计算表明利用会聚光束在负色散克尔介质中传输的耦合作用,可以压缩脉宽,这可作为一种新的压缩脉宽的方法。     

应用微机定时技术控制小直流电机转速的实验

介绍了采用微机定时计数接口技术实现脉宽词制，以控制小直流电机转速实验的实验方案，并对实验结果进行了讨论．     

多模气体激光纵模线型函数及其频宽的实验观测

本文根据多模激光时间相干性ｇ（１）（τ）的准周期性特点，提出了一种观测多模激光纵模线型函数及其频宽的新方法－程差２ｋＬ法。文章介绍了测量原理与方法，并以双模Ｈｅ－Ｎｅ激光器为例，给出了相应的实验结果，研究表明，多模气体激光的纵模线型函数为洛仑兹（Ｌｏｒｅｎｔｚ）线型函数，相应的纵模频宽约为１０＾７Ｈｚ。     

厚层抗蚀剂显影轮廓分析

DILL上曝光模型和MACK显影模型，编制了接触式曝光系统的厚层抗蚀剂光刻模拟软件，用其分析在理想曝光剂量条件下，抗蚀剂显影后的线宽和侧壁陡度随显影时间的变化规律，分析得出了给定厚度的抗蚀剂的显影时间，为实验工艺上严格控制显影时间提供依据。     

A new algorithm on PMD pulse-width compression

An algorithm on PMD pulse-width compression is proposed. The new algorithm is more efficient than some recent result and is guaranteed to be globally convergent. Also all iteration points are feasible Jones vectors. These properties are important since in many situations, PMD control needs to be implemented in real time.