Outline Imaging by THz Time Domain Spectroscopy

Outline imaging by THz time domain spectroscopy is proposed. Spectroscopic splitting at interface is reported, The principle of outline imaging is put forward. Experimental results demonstrate the feasibility of outline imaging by spectroscopic splitting, It is shown that clear out：line image of sample interface could be achieved easily by this technique. The spatial resolution is about 0.6mm. The THz-beam focus, the scanning step and the THz pulse width are the critical foctors affecting the imaging resolution. The signal-to-noise ratio of this technique could be improved greatly compared to the conventional transsion imaging.     

Typical Microstructures of Chinese Medicines with X-Ray Microscopy in Phase Contrast

Due to the low absorption contrast of plant tissues, traditional x-ray radiography has not been included in the microscopic techniques used in the identification of traditional Chinese medicines （TCMs）. With the development of x-ray phase contrast imaging （XPCI） in recent years, weakly absorbing materials could also be imaged by x- rays. Here we investigate microstructures of TCMs utilizing XPCI based on a nano-focus x-ray tube. The results demonstrated that XPCI is capable of revealing the microstructures of TCMs used as judging criteria in the identification of TCMs. The major advantages of the new method are nondestructivity, no special demand for sample preparation and suitability for thick samples.     

利用数字重现电子全息图观测微电磁场分布

采用数字方法重构电子全息图，分别研究了荷电乳剂小球(0.31μm)的微电场分布及强磁材料中磁畴的磁力线分布精细结构.利用噪声消除及位相差放大技术提高了重现分辨率，并获得了一些新结果. 关键词：     

A Method for Quantitative Analysis of Chemical Mixtures with THz Time Domain Spectroscopy

A method for analysing chemical mixtures quantitatively with terahertz time domain spectroscopy is proposed. The experimental results demonstrate the feasibility of this technique. Transmission coefficient of THz wave at the sample surface is taken into account to improve the analytic precision, lsomer mixtures are chosen as the experimental samples. Compared to similar techniques, the analytic precision could be improved evidently in this method.     

样品内部非平行界面的反射式terahertz波层析研究

已有的反射式terahertz(THz)波层析研究都是针对平行界面进行，开展了样品内非平行界面的反射式THz波层析成像的数值模拟研究.根据物理模型给出了重构算法，并编制了相应的重构软件，数值计算结果表明非平行界面的重构是可行的.分析表明，重构误差主要来源于计算中的近似处理和累积误差.讨论了曲线轮廓界面的近似处理方法，提出当曲线轮廓各点的曲率半径都比较大时，可以把曲线分割成多段直线处理.最后分析了影响纵向分辨率的因素.结果表明，输入脉冲的脉宽越大则纵向分辨率越低，一般情况下纵向分辨率可达到亚毫米量级. 关键词： terahertz波 反射式层析成像     

核分析技术与材料科学

本文扼要地介绍了上海原子核所的核分析手段以及它在材料科学中的应用,它已在表面碰撞反应动力学,离子注入缺陷工程,纳米材料和纳米加工,以及团簇和富勒（Ｆｕｌｌｅｒｅｎｅｓ）等当今几个前沿材料科学研究领域中取得了较为显著的进展． In this paper the nuclear analysis techniques in the Shanghai Institute of Nuclear Research and their applications in material science have been briefly introduced. Progresses have been made during recent years in studies, in particular, on the surface collision dynamics, ion implantation defects, nanometer-scale materials and nanometer-processing,cluster and fullerene.     

Ar+离子束轰击在石墨表面形成六方金刚石纳米晶的研究

在0.6!keV Ar+高剂量(～1022/cm2)辐照石墨表面,借助于高分辨透射电子显微镜(HRTEM),发现有六方金刚石纳米晶产生.它们的平均直径介于1-50!nm之间,而且晶粒个数约随其直径的增大而直线减少.有趣的是,晶粒具有两种结构模式:直径小于10!nm的晶粒为单晶结构,而直径大于10!nm的为多晶结构.基于受离子轰击过程特点制约的六方金刚石晶粒成核和成长观点,讨论了这种双重结构的形成性质.     

新一代同步辐射光源及其应用

扼要地介绍了同步辐射的历史和现状，以及在我国建设新一代同步辐射光源的必要性，设计中的上海同步辐射装置（ＳＳＲＦ）在其建成时将具有世界一流的光源性能，和一批覆盖面广，兼顾基础研究，应用研究和产业发展及具有世界先进水平的光束线和实验站。     

钍基熔盐堆核能系统

裂变核能是保障能源增长需求和促进节能减排的重要手段。钍基核能具有中子增殖性能好、产生高放废料少和储量丰富等特点;熔盐堆作为第四代先进反应堆的6个候选堆之一,具有钍高效利用、高温制氢、无水冷却、适合小型模块化设计等优势和潜力。发展钍基熔盐堆,对中国的核能战略发展具有重要意义,将会有助于解决中国的能源和环境双重挑战。2011 年1 月,中国科学院启动战略性先导科技专项——钍基熔盐堆核能系统(TMSR),采取液态熔盐堆和固态熔盐堆两种堆型研发同时部署和相继发展的技术路线,致力于实现基于熔盐堆的钍资源高效利用和核能综合利用,为我国核能发展赢得先机。