多光子偏振态与单光子高维空间态之间的相互变换及其应用

基于一种特殊的控制非门,实现多光子偏振态与单光子空间高维态之间的相互变换,使得对多光子偏振态的操作可以通过对单光子的操作来完成,由此可以实现任意多光子正定算符值测量和多光子任意幺正操作.这种实现方式是以一定概率完成的,但其效率要优于此前的方案,在目前的实验条件下是可行的. 关键词： 单光子空间态 特殊控制非门 线性光学多端口干涉仪     

n,p柱宽度对超结SiGe功率二极管电学特性的影响

结合SiGe材料的优异性能与超结结构在功率器件方面的优势,提出了一种超结SiGe功率二极管.该器件有两个重要特点:一是由轻掺杂的p型柱和n型柱相互交替形成超结结构,取代传统功率二极管的n^-基区;二是阳极p⁺区采用很薄的应变SiGe材料.该二极管可以克服常规Si p⁺n^-n⁺功率二极管存在的一些缺陷,如阻断电压增大的同时,正向导通压降随之增大,反向恢复时间也变长.利用二维器件模拟软件MEDICI仿真 关键词： 超结 锗硅二极管 n p柱宽度 电学特性     

Optical switching and logic gates with hybrid plasmonic-photonic crystal nanobeam cavities

We propose a hybrid resonance architecture in which a plasmonic element is coupled to a silicon-on-insulator photonic crystal nanobeam cavity operating at telecom wavelengths. It benefits from the combined characteristics of the photonic cavity and the plasmonic element, and exploits the unique properties of Fano resonances resulting from interactions between the continuum and the localized cavity states. As confirmed through 3D time-domain simulations, a strong cavity mode damping by the plasmonic element offers mechanisms of controlling a probe signal propagating in the nanobeam. It makes possible to create optical switching devices and logic gates relying on any optical nonlinear effect.     

光驱动分子梭

分子梭在分子开关、分子逻辑门、信息存储等领域有着潜在的应用价值,是超分子化学领域的研究热点之一。本文综述了光驱动分子梭的研究进展：重点举例介绍了荧光光谱识别法和圆二色光谱识别法这两种识别光驱动分子梭位置状态的方法;阐述了构建光驱动轮烷分子梭的新型方法学,包括光驱动环糊精[2]轮烷和[1]轮烷分子梭的定向合成,举例介绍了光间接驱动的轮烷分子梭,以及光驱动[3]轮烷型分子梭和分子梭聚合物;举例说明了光驱动分子梭的功能性应用,用光驱动分子梭来模拟分子水平的逻辑门,研究光驱动分子梭体系中的能量传递机理,以及非溶液态的光驱动分子梭;并对分子梭今后的发展做了展望。     

Analysis of the sensitivity to the electrochemical potential of the width of a metallic nanoconstriction

In relation to a metallic nanowire in the presence of an electrochemical potential, the sensitivity to this potential of the nanowire width is evaluated by defining and calculating a suitable parameter that can be regarded as a normalized gradient, this gradient being the derivative of the above-mentioned width with respect to the electrochemical potential.     

On the Asymmetry for Convex Domains of Constant Width

The extremal convex bodies of constant width for the Minkowski measure of asymmetry are discussed. A result, similar to that of H. Groemer＇s and of H. Lu＇s, is obtained, which states that, for the Minkowski measure of asymmetry, the most asymmetric convex domains of constant width in R2 are Reuleaux triangles.     

Qualitative and quantitative analysis of voice onset by means of a multidimensional voice analysis system (MVAS) using high-speed imaging

High-speed filming is one of the most informative methods for assessing voice physiology data. Tracing high-speed images of the glottis provides quantitative parameters such as the glottal area and the glottal width function. By way of example, a number of studies are discussed which extract quantitative data from high-speed images showing voice onsets. Furthermore, a new computer system (MVAS; multi-dimensional voice analysis system) is presented that synchronously displays a laryngoscopic high-speed film, the electroglottographical signal, and several acoustic analyses of the recorded voice sample. The automatic measurement of glottal width and glottal area from the laryngoscopic images is also provided. Looking at former studies and our analyses of voice onsets reveals a tremendous intersubject and even intrasubject variability (different prephonatory closure, different time span until full amplitude is reached, different open quotient).     

Simulation of metastable zone width and induction time for a seeded aqueous solution of potassium sulfate

The metastable zone width (MSZW, ΔT_m) and induction time (t_ind) were determined with computer simulation for seeded batch crystallization of potassium sulfate from aqueous solution. The MSZW and induction time determined with simulation showed the same behavior as experimental values reported in the literature; log (ΔT_m) increased linearly with an increase in log R (R: cooling rate) and t_ind decreases in proportion to (ΔT)⁻ⁿ (ΔT: supercooling, n: nucleation order in the secondary rate expression of B=k_n(ΔT)ⁿ). The secondary nucleation parameters (k_n and n) were deduced both from the simulated MSZW and induction times by using the previously proposed model [J. Cryst. Growth, 2010, 312, 548–554]. The secondary nucleation rate calculated with the deduced parameters was in agreement with that calculated with the parameters input for simulation.     

Nucleation kinetics of paracetamol–ethanol solutions from metastable zone widths

A study of the nucleation kinetics for a cooling crystallisation of paracetamol–ethanol solutions in a batch reactor is described in this paper. Metastable zone width (MSZW) experiments were conducted in order to estimate the nucleation kinetics of the system. Measured MSZWs can be affected by numerous process parameters, such as cooling rate, concentration, agitation rate, and working volume. Two theoretical approaches were employed to estimate the nucleation kinetics, the classical mass based approach of Nývlt, and a more recent approach by Kubota, which also considers number density. Both approaches were found to produce similar estimates for the nucleation rates of the paracetamol–ethanol solutions as a function of supersaturation for an assumed nucleus size of 10 μm. The theory of Kubota was found to predict satisfactory estimates for the induction time of the nucleation process from MSZW data. The induction time was observed to be independent of the solution temperature as suggested by Kubota’s theory. This is a novel finding and serves to validate the induction time theory of Kubota. In this investigation, MSZWs were observed to decrease with increased levels of agitation and found to be independent of working volume.