关于洛埃德镜实验光强分布的讨论

对洛埃德镜实验的光强分布进行了分析和讨论,研究了线光源横向移动和光源线度对光强分布的影响,推导出了单一缝光源所产生的光强分布公式.     

多普勒频移对运动三能级原子稳态布居的影响

借助数值计算和图像法讨论了多普勒频移对运动Ξ型三能级原子在双色行波场中稳态布居的影响.结果表明,多普勒频移对共振位置有精细的影响,并且拉比频率越大多普勒频移更加明显.     

Lamb Wave Arrival Time Extraction Using Hilbert-Huang Transform for Improved Tomography Image

Travel time Lamb wave tomography has been shown to be an effective nondestructive evaluation (NDE) technique for plate-like structures.The methods used previously to extract arrival times of the fastest or multi Lamb wave modes are mostly based on various time-frequency methods such as Wigner-Ville distribution,short-time Fourier transform,and recently explored wavelet transform(WT).Frankly speaking,uses of these signal processing methods improve the accuracy of the arrival time extraction to a great extent...     

原码两位乘运算器的逻辑实现

以数学推导→算法分析→逻辑设计为线，详细论述原码两位乘运算器的实现过程，使读者深入理解运算器的设计思路。     

大功率连续可调直流电源的设计

大功率直流电源在工业生产中是一种常用的设备。通常采用控制晶闸管的导通角,而得到输出连续可调的直流电压。本文提出用集成运算放大器和时基电路产生大范围控制晶闸管导通角的触发信号,具有可靠性高,功耗小,调控范围大,调试容易等特点。     

RESEARCH ON CONFORMATION OF CAPROLACTAM AND ITS ALKYL DERIVATIVES

Caprolactam is treated with dimethyl sulfate in benzene medium under conditions of various molar ratios to yield two different methylatcd products. The homogeneous reaction of caprolactam with dimethyl sulfate without any medium can only givc one methylated derivative. In a similar condition to that mentioned above, the reaction of caprolactam with diethylsulfate forms also one product, O-ethyl caprolactim. In this articlc NMR spectrum is applied to further identify the molecular structures of two methylated derivatives held by predecessors, and, applied the chemical shift reagent to induce the NMR and combined the field scanning and decoupling method to confirm the classification of signals, as a consequence the preferred conformation of caprolactam and its alkyl derivatives are proposed.     

超等距膨胀及某些加权位移算子的完全酉不变量

给出某些有趣的加权单向位移算子的完全酉不变量，进一步发展了超等距可膨胀算子的概念。     

基于古斯-汉欣位移在级联型波导中增强的研究

利用级联型波导结构来增强古斯-汉欣位移.用两块完全相同的对称金属包覆波导制备级联型波导,研究了反射光束的古斯-汉欣位移增强效应.结果表明,当激光在级联型波导之间反射8次、波长从859.630nm变化到859.673 nm时,古斯-汉欣位移大于5 mm,消光比可以达到50 d B.     

一类随机生态系统的分岔行为和稳定性研究

建立了外界激励下湖泊富营养化随机生态系统模型,基于Stratonovich-Khasminiskii随机平均原理,利用FPK方法,研究了该随机生态系统的分岔行为;采用随机微分方程四阶Runge-Kutta格式,选用500条样本路径,并做平均,通过对该随机模型进行数值模拟,讨论了噪声强度对该生态系统稳定性和稳态转换情况的影响.结果表明,对应于不同的营养盐输入率,磷浓度的平稳概率密度函数分布随噪声强度的变化而变化;同时,该外界激励下湖泊富营养化随机生态系统仍然存在双稳态,在双稳态区域,直接影响磷浓度的随机干扰使生态系统变得不稳定;并且一定的外界干扰强度可以使生态系统发生跃迁.