基于菲聂尔透镜的聚焦太阳能PV/T 系统热电性能研究

本文建立了基于菲涅尔透镜的聚焦型PV/T热电联产系统的一维稳态传热模型,对六种不同结构的PV/T系统的热、电效率和(火用)效率进行了计算,利用(火用)效率作为评价标准对六种系统进行了比较.分析表明采用聚焦型PV/T系统,在牺牲少量发电效率的基础上,可以获得具有一定温度的热能;增添玻璃盖板虽然能够减少热损失,但同时使得系统的光学效率降低,减少电池上的能量密度,反而使得系统的(火用)效率降低1%;环境恶劣的情况下,应将集热管外加保温腔体,透镜起到盖板和聚光器的双重作用,在不损失发电量的同时可以提高系统的热效率.     

铷原子中参量六波混频和量子拍的研究

在铷原子中实现了轴向相位匹配的参量六波混频,并探测到位于红外光谱区的六波混频信号.六波混频信号与泵浦激光进行和频,产生了位于可见光范围内的可调谐的和频信号,并从和频信号中观察到频率为608 cm 1的量子拍.结果表明,六波混频信号中的量子拍能够用于研究原子和分子的相干特性.     

Measurement of Diffusion Coefficient of Liquids by Using an Asymmetric Liquid-Core Cylindrical Lens： Observing the Diffusion Process Directly

We report a method for measuring diffusion coefficient D of liquids by using an aplanatic and asymmetric cylinder lens with a liquid core, which is designed as both a diffusion pool and the main imaging element. The precision is better than 10-4 RIU in measuring refractive index. The D values of ethylene glycol （EG） in water are measured for various EG concentrations at 25℃, and Dinf = 1.043 × 10^-5 cm^2/s under the condition of infinite dilution is obtained. The method is characterized by observing the diffusion process directly, faster measurement and obtaining the D value under the condition of infinite dilution.     

Novel Covalently Linked Self-Assembled Films from a Functional Hyperbranched Conjugated Poly(Phenylene Vinylene)

The hotSPOt in the fields of molecular films focuses on highly ordered, ultrathin filmswith molecularly controllable surface properties. It is attractive tO stUdy supramolecularfunctional POlymeric materials with suitable physical properties and abilities to formorganized superstrUctures at the interfacesl'2'3A. Dendritic macromolecules are a kind ofmaterials which is capable of self-organizing into superstrUctUres'. So a new dendrimerlike POly(Phenylene vinylene)- --hyperbranched conj "…     

色散耦合道光学模型对28Si的核子散射数据分析

在光学势中引入色散关系, 相比于通常的耦合道光学模型, 极大地减少了光学势 参数的个数. 采用基于软旋转子模型的耦合道方法对较轻形变核²⁸Si核的中子和质子散射实验数据进行了计算分析, 拟合得到一组色散光学势参数. 计算的中子总截面、以及中子、质子的弹性与非弹性散射微分截面与实验数据有较好的符合.     

利用微扰法分析两个相互耦合的参量四波混频过程

利用微扰法在旋转波近似下分析了铷原子中两个独立的参量四波混频过程和一个耦合的参量四波混频过程.当用超短激光脉冲相干激发这两个参量四波混频过程时,两个过程就会同时出现并且存在相互耦合作用.微扰分析表明,耦合的参量四波混频信号中可以观察到量子拍,量子拍幅度的大小不仅取决于超短脉冲的特性,而且依赖于两个耦合的参量四波混频过程中的相位匹配.     

苯胺蓝分光光度法测定痕量铬(Ⅵ)

在HCI介质中,铬(Ⅵ)与过量I-反应生成黄色 I-3,继而与水溶性苯胺蓝阳离子形成离子缔合物,使得苯胺蓝溶液褪色,其在605nm处产生一个强吸收峰.在最佳实验条件下,Cr(Ⅵ)的浓度在4.0×10-7-1.2×10-5mol/L范围内符合比耳定律.表观摩尔吸光系数ε为1.10×106L·Mol-1·cm-1.该法用于分析测定沱江水样中Cr(Ⅵ)的含量,结果令人满意.     

Single-Photon Detection at Telecom Wavelengths

A single-photon detector based on an InGaAs avalanche photodiode has been developed for use at telecom wavelengths. A suitable delay and sampling gate modulation circuit are used to prevent positive and negative transient pulses from influencing the detection of true photon induced avalanches. A monostable trigger circuit eliminates the influence of avalanche peak jitter, and a dead time modulation feedback control circuit decreases the afterpulsing. From performance tests we lind that at the optimum operation point, the quantum efficiency is 12% and the dark count rate 1.5 × 10^-6 ns^-1, with a detection rate of 500 kHz.