SEM与TEM的区别

一、性质不同

1、SEM：根据用户使用搜索引擎的方式利用用户检索信息的机会尽可能将营销信息传递给目标用户。

2、TEM：把经加速和聚集的电子束投射到非常薄的样品上，电子与样品中的原子碰撞而改变方向，从而产生立体角散射。

二、原理不同

1、TEM

（1）吸收像：当电子被发射到高质量和高密度的样品时，主要的相位形成是散射。当样品的质量和厚度较大时，电子的散射角较大，通过的电子较小，图像的亮度较暗。早期透射电子显微镜（TEM）就是基于这一原理。

（2）衍射像：电子束被样品衍射后，样品不同位置的衍射波振幅分布对应于样品中晶体各部分的不同衍射能力。当出现晶体缺陷时，缺陷部分的衍射能力与整个区域的衍射能力不同，使得衍射波的振幅分布不均匀，反映了晶体缺陷的分布。

2、SEM

（1）用户搜索；

（2）返回结果；

（3）查看结果；

（4）点击内容；

（5）浏览网站；

（6）咨询搜索。

扩展资料：

TEM特点：

1、以电子束为光源，电磁场为透镜。电子束的波长与加速电压（通常为50-120千伏）成反比。

2、它由五部分组成：电子照明系统、电磁透镜成像系统、真空系统、记录系统和电源系统。

3、分辨率为0.2nm，放大倍数可达一百万倍。

4、透射电镜分析技术是一种高分辨率（1nm）高倍率的电子光学分析技术，它以波长很短的电子束为光源，聚焦于电磁透镜成像。

5、用透射电镜分析样品，通常有两个目的：一是获得高倍率的电子图像，二是获得电子衍射图样。

6、透射电镜常用于研究纳米材料的结晶，观察纳米颗粒的形貌和分散度，测量和评价纳米颗粒的粒径。这是表征纳米复合材料微观结构的常用技术之一。

参考资料来源：百度百科-TEM

参考资料来源：百度百科-搜索引擎营销

Objective: to use electricity spinning method for preparation of e. coli phage, molecularly imprinted polymer membranes of the template. In this test requirements with the whole process of scientific research, including data collection, the subject designing, experimental operation and professional writing the thesis. While improving students' scientific thinking ability and practical ability.

Methods: using mpeg precipitation + chloroform extraction smoke concentration purification phage reach 1012 / ml, concentration of PVA by adjusting voltage, high flow rate, and spinning, the preparation conditions after film by scanning electron microscope (SEM) spinning solution concentration, flow, voltage, high on spinning fiber diameter and the morphology of the influence. Using the electrostatic spinning technology in preparation for the conditions for the "shell" with PVA, escherichia coli phage as "core" of molecularly imprinted membrane, and through the double plaque method of observing AGAR bite after encapsulation testing of bioactive phage.

Results: the successful condensed phage reach 1012 / ml. In the process of preparation conditions with water groping for solvent for 7% PVA concentration (w/w) of membrane 2, Before joining ethanol and SM, spinning is unstable, lots of broken wire and beads, liquid membrane, not because of time, not continue, experiment which terminates. Turn on the morphology, PVA spinning fiber diameter with PVA concentration, the relationship between voltage

Conclusions: (1) by the preparation of several membranes observed results show that, with the increase of spinning solution concentration, fiber diameter increase gradually, the distribution of fiber diameter with, With the increase of fiber diameter, voltage did not change significantly.

2, the experiment of polymer matrix phage and spinning compatibility of PVA were evaluated.

[key] : a phage maximizing electrostatic spinning PVA

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