陶瓷材料的加工变质层结构及相变

利用透射电镜和Ｘ射线衍射仪对氧化锆、赛龙陶瓷的变质层结构和加工表面的相变等作了较深入的探讨，研究表明在磨削后采用研磨和抛光工艺可减少表面残余应力、加工变质层和相变，降低表面粗糙度，改善已加工表面的质量。     

高聚物的STEM象观察

将分析电子显微镜的扫描透射电子象模式(STEM)应用于两种高分子物的研究。以 ABS/PVC高分子合金和角蛋白纤维为试验材料,叙述了样品制备过程和电镜观察的结果。实验证明,STEM具有对试样穿透能力强和电子束损伤小的特点,特别适用于高聚物材料。在高放大倍数下的观察,能获得直接透射象(TEM)难以观察到的某些微结构情景。     

关于波导管内不能传播TEM波的简单证明和唯象解释

本文从·E=0及×E=iωμH两式出发,无须解出波导管内电磁场的各个分量或横向分量与纵向分量的关系,即可证明波导管内不能传播TEM型电磁波,并从物理概念出发给出一个更简捷的唯象说明。     

基于电子束辐照的无机气溶胶颗粒PM1.0污染特征及S元素分布变化研究

为了更好的了解不同来源无机气溶胶颗粒PM1.0的颗粒模态和颗粒相中化学相的组构状态,探讨颗粒表面污染的吸附-转化特点以及与非均相反应过程的对应关系,文章利用场发射透射电子显微镜TEM结合能谱仪EDS,基于电子束平行辐照模式下的持续辐照/分段采谱的方法,以单颗粒分析的方式统计分析了不同来源无机气溶胶颗粒PM1.0的颗粒混合态和污染特征,并对电子束持续辐照下颗粒模态的转化过程进行了探讨。同时,通过电子束持续辐照下S/Si相对含量变化规律,近似评估PM1.0不同来源颗粒物颗粒中S的含量与分布变化。     

In-situ potential mapping of space charge layer in GaN nanowires under electrical field by off-axis electron holography

In situ potential mapping of space charge(SC) layer in a single Ga N nanowire(NW) contacted to the Au metal electrode has been conducted using off-axis electron holography in order to study the space distribution of SC layer under electric biases. Based on the phase image reconstructed from the complex hologram the electrostatic potential at the SC layer was clearly revealed; the SC width was estimated to be about 76 nm under zero bias condition. In order to study dynamic interrelation between the SC layer and bias conditions, the variation of the electrostatic potential due to change of the SC widths respond to the different bias conditions have also been examined. The measured SC layers are found to vary between68 nm and 91 nm, which correspond to the saturated SC layers at the Ga N-Au contact under the forward and reverse bias conditions, respectively. By plotting the square widths of the SC layer against the applied voltages, donor density of Ga N NWs was derived to be about 4.3*10~6cm~(-3). Our experiments demonstrate that in-situ electron holography under electric fi eld can be a useful method to investigate SC layers and donor density in single NW and other heterostructures.     

Observation of Pt-{100}-p(2×2)-O reconstruction by an environmental TEM

The surface structure of noble metal nanoparticles usually plays a crucial role during the catalytic process in the fields of energy and environment. It has been studied extensively by surface analytic methods, such as scanning tunneling microscopy. However, it is still challenging to secure a direct observation of the structural evolution of surfaces of nanocatalysts in reaction(gas and heating) conditions at the atomic scale. Here we report an in-situ observation of atomic reconstruction on Pt {100} surfaces exposed to oxygen in an environmental transmission electron microscope(TEM). Our high-resolution TEM images revealed that Pt-{100}-p(2×2)-O reconstruction occurs during the reaction between oxygen atoms and{100} facets. A reconstruction model was proposed, and TEM images simulated according to this model with different defocus values match the experimental results well.     

ω_o phase precipitation in annealed high Nb containing TiAl alloys

The ordered ω phases in high Nb containing Ti Al(Nb-Ti Al) alloys have been garnering increasing attention in the recent years. However, the investigations on the Nb dependence on the ωoprecipitation are scarce. In this study, the effect of Nb content on the ωoprecipitation in high Nb(6–10 at%) containing Ti Al alloys after long-time annealing at 850 1C has been studied. The results show that small ordered ω particles in the retained βophase cannot be discerned under scanning electron microscope(SEM) but can be observed using transmission electron microscopy(TEM). Although the Nb segregation can be eliminated after the homogenization heat treatment, the ωophase precipitated in all the alloys studied after annealing at 850 1C. TEM examination reveals that the orientation relationship between the ωoand α2phases can be derived as: [0001]ωo//[1120]α2;(1120)ωo//(0001)α2, which indicates that the ωophase is directly transformed from the parent α2phase. Small γ particles are also observed within the ωoareas. The α2-ωot γ decomposition process is expected during annealing. It is concluded that ωophase is an equilibrium phase in high Nb-Ti Al alloys at 850 1C.     

V8系统TEM原始曲线绘制的MATLAB程序实现

瞬变电磁测深勘探中,衰减曲线和晚期视电阻率曲线图作为原始资料是野外资料验收的核心内容之一,而仪器配套的预处理软件往往不能批量地生成相应的图件,技术人员需从软件中截图来实现,这一工作不但繁琐,而且缺乏相应的信息。通过编制MATLAB程序读取相应的USF数据,实现原始曲线的批量绘制,并可进行试验数据的对比分析。     

基于MAXWELL的瞬变电磁“8”字形发射线圈仿真分析

针对瞬变电磁技术在工程应用中易受干扰、探测结果不准确的问题,本文提出了一种瞬变电磁“8”字形发射线圈方案。采用MAXWELL仿真软件对瞬变电磁“8”字形发射线圈和方形发射线圈进行了仿真分析,通过对比“8”字形发射线圈和方形发射线圈在不同大小电流情况下产生的磁场分布发现,“8”字形发射线圈在远距离位置具有较强的聚焦性,在近距离位置能产生明显大于方形线圈的磁通密度。所以“8”字形发射线圈对增强瞬变电磁超前探测的抗干扰能力和提高探测结果的准确度具有重要作用。