同时获得高亮度检测场和高衬比条纹的实时全息记录方法

讨论了实时全息法应用于检测透明物体的情况下获得高衍射效率和高衬比条纹的若干问题。给出了同时获得高亮度检测场和高衬比条纹的最佳参数。在最佳光束比等于１和最佳相位调制度为１．４２时,衍射效率和光能利用率均可达到２９％。     

对堆叠物体保持直立下落条件的探究

相同的物体彼此堆叠,形成独立的塔.通过施加突然的水平力来卸下底部物体,以使塔架的其余部分下降到地面上,并且塔架保持直立.本实验将研究该现象并确定允许塔保持直立的条件.从项目本身出发,选择不同形状的物体进行实验,采用控制变量法对块的数量、块的规格,水平力的大小等相关变量进行实验和探究.先利用所学的动力学知识从理论上分析,...     

萃淋树脂CL—P507吸附分离钨,钼的研究：Ⅰ.树脂的吸附及分离性能

本文考察了萃淋树脂CL-P507对钨、钼的吸附性能,测定了树脂的饱和吸附容量,得出了在H_2SO_4-EDTA体系中从含大量钨的溶液中分离钼的条件。     

基于变分等值线方法的图像分割技术

使用level set,函数来隐式地追踪目标图像,给出了level set函数的变分模型和相应的 Euler-Lagrange方程．在保证level set函数的等值线在目标图像附近的运动速度渐趋于零的前提下,改进了原来的Euler-Lagrange疗程,加快迭代速度．可灵活地调节模型参数以满足不同的分割要求．文中算例说明本模型的有效性、灵活性．     

偏振方向对THz电光探测影响的理论研究

采用线性电光效应耦合波理论，系统地研究了用无中心反演对称性的立方晶系晶体作为探测晶体时，terahertz(THz)辐射信号和探测光的偏振方向对电光探测的影响. 研究结果发现，THz辐射和探测光的偏振方向都对电光探测影响很大，沿(110)方向传播时可以获得最大的探测灵敏度，最适合THz的横场探测. 计算研究的部分结果与已有的实验结果相一致，可为电光探测器的设计提供有用的指导. 关键词： 电光探测 THz辐射 偏振 线性电光效应耦合波理论     

Electrospray/VUV single-photon ionization mass spectrometry for the analysis of organic compounds

For the comprehensive analysis of organic compounds, especially thermal labile and nonpolar compounds, an electrospray/vacuum ultraviolet (VUV) single-photon ionization (ES-SPI) method was developed. The fine droplets of the sample solution from the electrospray process were directed through a quartz capillary and two skimmers to form a molecular beam into a high vacuum ionization chamber. The neutral sample molecules were softly ionized with tunable VUV light and analyzed with a reflection time-of-flight mass spectrometer (RTOF-MS). The ionization energy (IE) and appearance onsets of fragments were obtained based on the photoionization efficiency (PIE) spectrum. The isomers can also be distinguished. With this new method, clean (fragment-free) mass spectra of nonpolar compounds, such as benzene, cyclohexane, and some thermal labile solid compounds (triphenylamine, thioacetamide, and urea) have been obtained without any tedious pretreatment. The components of complex mixtures (gasoline and kerosene) can be identified. Furthermore, quantitative analysis of the components can be obtained based on photoionization cross section data. This method may be used for quantitative analysis of small biomolecules and natural products.     

空间相位调制对光伏孤子传播的影响

利用空间相位调制技术控制高斯光束在光伏晶体中的传播.数值分析结果表明，适当地选择各调制参数，可以使光束以类孤子的形式传播，或使光束发生自偏转、分束、发散.还进一步就中心光强、半高全宽的大小对相位调制的影响作了定性的分析. 关键词： 空间光学孤子 空间相位调制 光开关 光偏转 光分束     

Modulation instability of broad optical beams in nonlinear media with general nonlinearity

The modulation instability of quasi-plane-wave optical beams is investigated in the frame of generalized Schr(o)dinger equation with the nonlinear term of a general form. General expressions are derived for the dispersion relation, the critical transverse spatial frequency, as well as the instability growth rate.The analysis generalizes the known results reported previously. A detailed discussion on the modulation instability in biased centrosymmetric photorefractive media is also given.     

斐波那契序列与准晶态

本文从兔子繁殖的数学问题谈起,引入Fibonacci数列.研究了晶体的准周期结构,表明它与Fibonacci数列有密切的关系.