基于实时优化单光子干涉可视度的相位编码量子密钥分发

在相位编码量子密钥分发系统中,单光子干涉可视度决定了系统的成码率。本文提出一种优化单光子干涉可视度的方法,即利用遗传算法和四通道偏振控制器实时补偿单光子偏振漂移,同时利用时分复用参考光连续无复位地补偿单光子相位漂移,最终在25km光纤中实时优化的单光子干涉可视度达到98.6%,相位编码量子密钥分发系统成码率为2.2kbit/s。     

Removing the Destructive Quantum Interference in Cross Conjugation System by Structural Restraint

Understanding the quantum effect in the cross-conjugated system is of fundamental significance in molecular electronics. In this study, four molecules Xa-O, Xa, BP and BP-O were synthesized to investigate the destructive quantum interference(DQI) of a carbonyl bridge. The single-molecule conductance measured by the scanning tunneling microscope break junction(STM-BJ) technique demonstrates an increase in the conductance from molecule BP-O to molecule Xa-O as the cross-conjugated system is extended. Theoretical calculations show that the explicit DQI feature is presented in BP-O but absent in Xa-O, which indicates the removal of DQI in the restrained structures and results in the conductance enhancement in Xa-O.     

高压密闭消解-电感耦合等离子体质谱(ICP-MS)法测定土壤背景点样品中的29种元素

土壤环境背景值监测样品的检测工作特点是分析项目多、前处理方法和分析方法复杂,缺乏简便多元素同时测定的分析方法。采用氢氟酸-硝酸体系高压密闭消解方法处理土壤样品,采用ICP-MS法同时测定锂、铍、硼、锗、钼、银、镉、铟、锡、碲、锑、铯、镨、钕、钐、铕、钆、铽、镝、钬、铒、铥、镱、镥、钽、钨、铊、铋和铀元素。系统研究了不同消解体系、质谱干扰和消除方法并选择了合适的测定同位素,采用土壤标准物质对方法适用性进行了考察,29种元素的检出限在0.003~0.469 mg·kg-1之间,测定值的相对标准偏差在1.0%~9.3%之间,测定值与标准值的相对误差在-14%~17%之间。方法满足土壤环境背景值监测工作的测试需求,可实现一次前处理多元素同时测定,提高了工作效率。     

Simultaneous LIF and retro-reflected beam interference detection for CE

This Short Communication describes a novel optical detection method for CE, based on the combination of LIF detection and retro-reflected beam interference detection. By the use of a side-illuminated laser beam, an on-column multifunctional detection for CE has been developed, and some key elements in the scheme have been optimized. In addition, two miscellaneous samples including fluorescent dyes, carbohydrates and amino acids have been determined to evaluate its performance. Without any additional pretreatment, sufficient LOD and linear ranges have been achieved for most analytes. Its performance in retro-reflected beam interference detection is better than those mentioned in a former report, and its fluorescent sensitivity is comparable with the achievable sensitivity by conventional LIF systems, all of which together combine high sensitivity and universal analysis to a certain extent.     

Concentration of Analytes on the Probe in an Electrothermal Atomizer

To increase the sensitivity of the atomic-absorption analysis, we suggest concentrating the analytes on a tungsten probe through multiple fractional condensation of the sample vapor obtained in a graphite atomizer. This technique makes it possible to additionally reduce the matrix interference. To this end, a sample with a high interference level is preliminarily diluted to the level eliminated by the stage of fractional condensation and then concentrated on the probe. The influence of potassium sulfate on the Pd, Cd, and Ag absorption has been reduced by a factor of 1.5–4.5 and that of sodium chloride — by a factor of 4–300 compared to the influences in the longitudinally heated atomizer with a platform, a modifier, and a background corrector based on the Zeeman effect. In a number of cases, advantages over the transversely heated atomizer have been attained.__________Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 2, pp. 256–259, March–April, 2005.     

二次电位分布静电双棱镜

本文提出了一种新的静电双棱镜——二次电位分布静电双棱镜,用此棱镜可增强干涉电子的强度,并扩大等间距干涉条纹的区域.     

干涉条纹分析的空间扫描方法

本文讨论在垂直载频条纹方向进行空间扫描方法,以干涉图来确定波前的形状,精度约为(λ/50)的标准误差.     

Statistics of a random plus constant vector with application to acoustic and electromagnetic-wave scattering

A two-dimensional random-walk problem is investigated, where a vector fixed in amplitude (magnitude) is added to one that is random in phase (direction angle). This problem can arise from a study of the effect of multipath interference from an acoustic or electromagnetic-wave source, where an arrival of constant amplitude is combined with an incoherent background of randomly scattered components of the incident field. The source is considered to have harmonic time dependence. This study follows from an earlier paper, in which the required properties of the incoherent background were derived. In the present study, the joint distribution of the resultant amplitude and of the phase angle between the resultant and the fixed arrival is determined. Further, expressions are developed for the first and second moments of the resultant phase, amplitude, decibel-amplitude, and intensity. Many properties of these moments are described.This work was supported in part by Acoustic Programs, US Office of Naval Research and in part by the Electric Boat Division of General Dynamics.     

免标记光学生物传感器研究进展

免标记光学生物传感器因分析样品无需标记、强特异性、动态测量、无损检测、分析速度快等诸多优点,在化学、药学及生物等诸多领域中得到了快速发展和广泛应用。本文重点介绍了当前发展成熟且具代表性的四种免标记光学生物传感器,即表面等离子体共振传感器、光波导光模光谱传感器、椭圆偏振光学传感器以及反射干涉传感器,对每种传感器的原理结构、方法发展及在生化分析等相关领域中的最新应用进行了总结和论述;在此基础上,对它们各自的性能进行了优劣比较;最后对免标记光学生物传感器的发展前景进行了展望。