软x射线近贴显微技术

软x射线近贴显微技术不但可使活的生物样品成象,分辨率高于光学显微镜,而且人为的样品准备程序在该技术中都可避免。本文描述了用高功率激光打靶产生的等离子体作为软x射线源而进行的近贴显微研究,并得到了分辨率好于1μm的结果。     

荧光素单磷酸酯的合成和其应用于荧光光度法测定酸性磷酸酯酶

本文新合成了荧光素单磷酸酯,通过元素分析、红外、热谱确定了其结构,探讨了其生成机理,并将其应用到酸性磷酸酯的荧光分析,深入研究了它与酸性磷酸酯酶之间反应的条件、检测此酶的线性范围、检测限和米氏常效.     

闪光X射线高速摄影荧光转换屏的设计和性质研究

本文描述了用于中间弹道高速摄影荧光转换屏的设计特点、性能测试和实验结果。文中讨论了Gd2O2S:Tb和(Zn,Cd)S对X射线的吸收系数、发光效率以及荧光光谱与变象管S-20阴极光谱灵敏度曲线相匹配的相关曲线;测试了转换屏的相对发光强度、分辨率及其余辉。实验证明本屏发光亮度比钨酸钙屏高60倍左右,屏分辩率达51p/mm,余辉时间为8μs,多幅摄影结果证明第一幅的图象对第二幅照片无“拖尾”现象,本屏已达到了中间弹道高速摄影转换屏的实用水平。     

Development of a portable and fast wire tension measurement system for MWPC construction

In a multi-wire proportional chamber detector(MWPC), the anode and signal wires must maintain suitable tension, which is very important for the detector's stable and accurate performance. As a result, wire tension control and measurement is essential in MWPC construction. A high pressure3 He MWPC detector is to be used as the thermal neutron detector of the multi-functional reflectometer at China Spallation Neutron Source, and in the construction of the detector, we have developed a wire tension measurement system. This system is accurate,portable and time-saving. With it, the wire tension on an anode wire plane has been tested. The measurement results show that the wire tension control techniques used in detector manufacture are reliable.     

Calculation of acoustical radiation force on microsphere by spherically-focused source

Based on the ray acoustics approach, the trapping effects on a microsphere by an ideally spherically-focused ultrasound are discussed. The acoustical radiation force from a focused ultrasound beam on a spherical particle in a three-dimensional sound field is calculated considering the effect of the attenuation of the ultrasound beam both inside the particle and in the surrounding medium. The results show that as long as the particle is in the range of the ultrasound beam and as long as the appropriate parameters of the transducer are selected, the particle will be captured in the vicinity of the focus of the ultrasound beam. Also, the particle radius and different parameters of the transducer are analyzed for their affect on the radiation force.     

Demonstrating nonlocality-induced teleportation through Majorana bound states in a semiconductor nanowire

It was predicted by Tewari et al. (2008) [15] that a teleportation-like electron transfer phenomenon is one of the novel consequences of the existence of Majorana fermion, because of the inherently nonlocal nature. In this work we consider a concrete realization and measurement scheme for this interesting behavior, based on a setup consisting of a pair of quantum dots which are tunnel-coupled to a semiconductor nanowire and are jointly measured by two point-contact detectors. We analyze the teleportation dynamics in the presence of measurement back-action and discuss how the teleportation events can be identified from the current trajectories of strong response detectors.     

ICP-AES测定高浓度基体下杂质元素的偏最小二乘法研究

建立了ICP-AES测定高浓度基体中微量杂质元素的偏最小二乘方法(PLS)。研究表明,PLS能有效校正高浓度基体干扰引起的测量误差,比多元光谱拟合法(MSF)能承受的基体浓度更高。当基体与杂质的含量比为1 000∶1～20 000∶1时,该方法的加标回收率在95%～105%之间。对于干扰效应与基体浓度呈非线性相关的体系,普通PLS的预测准确度不高,但使用基于样品浓度矩阵变换的偏最小二乘法(LIN-PPLS),则明显改善了预测的准确度。分别用MSF、普通PLS和LIN-PPLS对水系沉积物国家标准物质GBW07312中的Co,Pb和Ga进行测定,结果表明,LIN-PPLS的预测准确度优于普通PLS,而普通PLS的预测准确度优于MSF。     

应用角谱方法研究聚焦声束在层状生物组织中的非线性声传播

应用角谱方法理论研究了聚焦声束在层状生物组织中的非线性传播特性，将声波分解为角谱，可计算垂直于声轴的任意平面的非线性声场。在圆形平面活塞聚焦换能器的焦区中插入多种生物组织样品，数值计算了样品内部及外部的二次谐波声场，并通过实验测量验证了理论方法的有效性。基于快速傅氏变换的角谱方法可直观地描述非线性声传播，对非线性声成像有指导作用。     

单色仪转角重复精度的相位板衍射准直方法测量

为准确测量上海光源软X射线谱学显微光束线采用的变包含角平面光栅单色仪的转角重复精度,提出了一种新的基于相位板衍射准直技术的测量方法.该方法将半导体激光单模光纤和相位板衍射准直技术结合起来,利用面阵CCD采集图像,通过测量光斑的位移变化确定平面镜和光栅的角度变化.实验表明.该方法可以测量掠入射情况下单色仪联动时的转角重复精度,测量精度可达士0.1",此测量精度优于同等实验条件下的商用ELCOMAT 3000自准直仪的测量精度.     

短波碲镉汞光伏器件的低频噪声研究

对所研制的短波光伏碲镉汞器件进行了变温电流-电压特性和低频噪声研究，测试温度范围255—293K.实验结果表明随着温度的下降，器件的优值因子R₀A从45×10³Ωcm²增加到7×10⁴Ωcm².器件在低频区的主要噪 声成分是1/f噪声和产生-复合噪声，在高频区主要是散粒噪声.在测试的偏压内，器件的1/f噪声功率谱密度与流过器件的电流的平方成正比，器件的Hooge系数为3×10^-4—7×10^-4.从噪声 功率谱密度曲线分析中得到产生-复合噪声的特征时间常数τ，通过τ的温度特性得到了器件的深能级. 关键词： 碲镉汞 优值因子 低频噪声 深能级