电子显微镜下的纳米世界

以高中阶段知识为基础,简述了扫描电子显微镜、透射电子显微镜等电镜技术的发展和基本原理,并以实际应用案例介绍了电镜技术在纳米科学领域的应用,最后给出了电镜技术的未来发展前景。     

CM200透射电子显微镜保护关机的故障分析及维修

介绍了CM200透射电子显微镜电镜保护(LPR)的工作原理,分析了电镜保护关机的故障原因并介绍了几个维修实例.     

一种简易扩散泵封闭式加热器

介绍了一种用电镜扩散泵的封闭式加热器。它具有结构简单，安装及检修方便，成本低廉等特点，该装置适用于ＪＥＭ－２００ＣＸ电镜及ＪＥＥ－４Ｘ真空喷镀仪配置，近年来的使用证明该装置完全可以替代原装进口封闭式加热器。     

JSM-5610LV扫描电镜的日常维护及常见故障排除

在扫描电子显微镜的日常维护管理中,应当控制好室内环境因素,保持电镜内部长期处高真空状态,定期检查其附属设备是否达到要求,介绍电镜经常出现的死机、黑屏显示图像不正常等故障的排除方法。     

H-800型电镜真空系统故障部位判定和维修

本文将“故障要因图”法应用于电镜真空系统的维修中，作出了H-800型透射电镜真空系统的故障要因图，并依据这一要因图对H-800型电镜真空系统的实际故障进行分析，比较准确地判定了故障部位，指出利用故障要因图分析和查找电镜真空系统故障的部位和原因能取得好的效果。     

电镜联机图象处理与分析系统的研制

设计了一个慢扫描图象结口与通用微机联接。不用帧存贮器，实现了扫描电镜图象采集、数字处理和返回电镜拍照，图象空间分辨率达到１０２４×７６８，图象灰度分辩率达到２５６级；除了图象处理和分析测量功能具有新的特色外，还将目前非常活跃的分形分析方法融入其中；采用浮雕式全汉化菜单（也可用西文），弹出式提示和问答窗口；菜单和图象同屏幕显示，结构紧凑。     

JEM-2100PLUS透射电子显微镜操作方法与技巧及常见故障排除

以JEM-2100PLUS透射电子显微镜为例，介绍了电镜的基本结构、操作面板和成像原理。使用透射电子显微镜的最终目的就是要得到高质量的照片，结合透射电镜的操作步骤，总结了如何拍摄高质量的照片以及常见故障排除方法。     

透射电镜像转角的测定及应用

论述了完全标定透射电镜像转角所需拍摄的二次曝光电子显微像的数量,推导了由已测的像转角间接计算其它像转角的一般公式,以Philips Cm200电镜为实例,说明了测定像转角的基本步骤,并以实例说明怎样利用像转角,把衍射花样的晶体学信息传递给电子显微像。     

对双光束激光诱导沉积氧化锌膜的电镜测定

报道了采用双光束紫外激光辅助有机金属化学气相沉积（ＭＯＣＶＤ）技术获得氧化锌（ＺｎＯ）薄膜（厚度５０－２００ｎｍ）的电镜研究结果。反射高能电子衍射（ＲＨＥＥＤ）和扫描电子显微镜（ＳＥＭ）指出，采用该生长在较低生长温度下，在云母衬底上易生长出沿ｃ轴取向的单晶膜。在云母、单晶硅和玻璃衬底上都可得到表面结构致密而均匀的微晶或晶膜。在适当条件下在玻璃衬底上还可以得到非晶膜。这些膜层均具有较好的可见光诱过率     

透射电镜CCD数字图像系统的研制

该系统利用计算机信息处理技术、CCD和合理的光路设计对普通的电子显微镜进行了改造,增加了一个图像处理系统,并成功地安装在H-600透射电镜上．该系统具有分辨率高、结构紧凑、成本低以及对原电镜结构不做任何改动等优点,可以广泛地用于国内大多数的透射电镜的改造,是进口设备优良的替代品．     

用于透射电子显微镜表征的单层纳米晶/聚合物复合薄膜的制备

为了提高纳米晶的TEM表征质量, 通过在水/气两相界面上铺展纳米晶/聚合物复合单层膜的方法, 制备了质量较高的TEM样品. 对于水相纳米晶采用表面活性剂再包覆的方法, 将其转移到油相. 与传统制样方法(尤其是水相合成纳米晶)相比, 嵌入聚合物膜中的纳米晶更容易分散(受到空间位阻与分子间弱相互作用等因素的影响), 并且聚合物膜可以自支持在空的铜网上, 从而提高了TEM照片的清晰度. 研究了系统中聚合物、纳米晶、表面活性剂和溶剂的种类及配比关系对于样品和成像质量的影响, 结果表明, 该方法对各种金属及半导体纳米晶的TEM表征具有一定的普适性.     

Enhanced visualization of polysaccharides from aqueous suspensions

Aqueous suspensions of polysaccharides such as those prepared for domestic and industrial applications or present in natural waters, although difficult to visualize by conventional transmission electron microscopy (TEM) because of their poor electron density, can be characterized at the ultrastructural level by using milden bloc staining and contrast enhancement by energy-filtered TEM (EF-TEM). The advantages and drawbacks of the proposed method are discussed in relation to the different parameters controlling the quality of final images. It is shown, with synthetic polysaccharides, purified algal fibrils and lacustrine exocellular polymers as key examples, that optimizing specimen preparation and visualization parameters allows unbiased identification of organic substructures never revealed or strongly degraded by classical microscopic procedures.     

Off-axis electron holography of unbiased and reverse-biased focused ion beam milled Si p-n junctions.

Off-axis electron holography is used to measure electrostatic potential profiles across a silicon p-n junction, which has been prepared for examination in the transmission electron microscope (TEM) in two different specimen geometries using focused ion beam (FIB) milling. Results are obtained both from a conventional unbiased FIB-milled sample and using a novel sample geometry that allows a reverse bias to be applied to an FIB-milled sample in situ in the TEM. Computer simulations are fitted to the results to assess the effect of TEM specimen preparation on the charge density and the electrostatic potential in the thin sample.     

无支持膜法TiO2纳米管透射电镜观察

用透射电镜观察纳米量级的样品,通常要承载在具有支持膜的铜风上观察,铜网上制膜虽然有多种方法,但者需要有一定的过程,经过实践,我们采取无支持膜法用铜网直接捞取TiO2纳米管样品,在诱射电镜下观察获得了比较满意的结果。     

动脉粥样硬化造影剂PGMA-EDA-g-PEG-g-DS@IO的合成及性能

利用乙二胺(EDA)对聚甲基丙烯酸缩水甘油酯(PGMA)进行开环反应, 制备了侧链多氨基聚合物PGMA-EDA; 再利用聚乙二醇(PEG-COOH)和硫酸葡聚糖钠盐(DS)分别对PGMA-EDA上氨基进行酰胺化反应和还原胺化反应, 制备含动脉粥样硬化斑块靶向分子DS的双亲性接枝共聚物PGMA-EDA-g-PEG-g-DS. 通过核磁共振(¹H NMR)谱和红外光谱(FTIR)表征了聚合物的结构. 利用凝胶渗透色谱(GPC)表征了聚合物的数均分子量M_n=16255, 多分散性指数PDI=1.54. 采用配体交换法, 利用该聚合物对油胺配体超顺磁性氧化铁纳米粒子进行修饰, 制备了水溶性氧化铁纳米粒子PGMA-EDA-g-PEG-g-DS@IO. 通过透射电镜(TEM)和动态光散射(DLS)表征了纳米粒子的形貌和粒度, 采用热重分析(TGA)和振动样品磁强(VSM)仪表征了纳米粒子的包覆率和磁强度. 采用细胞计数试剂盒(CCK)测定了纳米粒子的细胞毒性, 结果表明, 水溶性纳米粒子的生物相容性较好, 可作为动脉粥样硬化斑块的特异性磁共振检测用造影剂.     

Disordered spheres with extensive overlap in projection: image simulation and analysis

This article simulates highly overlapped projections of spherical particles that are distributed randomly in space. The size and number of the features in the projections are examined as well as how these features change with particle size and concentration. First, there are discernable features in projection even when particles overlap extensively, and the size of these discernable features is the expected size of an individual particle. Second, the number of features increases with specimen thickness at a rate of t(0.543) when the specimen thickness is below a critical value and becomes independent of specimen thickness at higher thicknesses. A criterion is established for the critical thickness based on particle size and particle volume fraction. When the specimen thickness is known and smaller than the critical thickness, a single representative transmission electron microscopy (TEM) (or scanning TEM) image exhibiting extensive particle overlap can be used to determine the size and number density of the spherical particles.     

PS／LDPE共混体系相结构的TEM研究

ＰＳ／ＬＤＰＥ共混体系相结构的ＴＥＭ研究徐世爱，江明，沈静姝（复旦大学高分子科学系和聚合物分子工程实验室，上海，２００４３３）（中国科学院化学研究所高分子物理开放实验室）关键词相结构，透射电镜，共混体系聚苯乙烯（ＰＳ）和低密度聚乙烯（ＬＤＰＥ）共混体...     

Improved focused ion beam target preparation of (S)TEM specimen--a method for obtaining ultrathin lamellae

Specimen quality is vital to (scanning) transmission electron microscopy (TEM) investigations. In particular, thin specimens are required to obtain excellent high-resolution TEM images. Conventional focused ion beam (FIB) preparation methods cannot be employed to reliably create high quality specimens much thinner than 20 nm. We have developed a method for in situ target preparation of ultrathin TEM lamellae by FIB milling. With this method we are able to routinely obtain large area lamellae with coplanar faces, thinner than 10 nm. The resulting specimens are suitable for low kV TEM as well as scanning TEM. We have demonstrated atomic resolution by Cs-corrected high-resolution TEM at 20 kV on a FIB milled Si specimen only 4 nm thick; its amorphous layer measuring less than 1 nm in total.     

A new view on chemistry of solids in solution--cryo energy-filtered transmission electron microscopy (cryo-EFTEM) imaging of aggregating palladium colloids in vitreous ice

It is shown that by using cryo-transmission electron microscopy (cryo-TEM) it is possible to image the aggregation behaviour of nanoparticles while they are still in solution. This technique has allowed the study of the arrangement of colloidal palladium particles in solution by preparing the specimen by the plunge-freezing technique. This method of rapidly cooling the specimen avoids rearrangement of the particles during specimen preparation. The palladium particles were identified by energy-filtered cryo-TEM. The aggregation of particles in solution was studied as a function of pH and ionic strength. The results can be used as recommendations for colloidal solutions intended for deposition of single particles.