[Objective] The study aimed to provide experiences for the researchers. [Method] With SEM as test material, observed surfaces of non-gilded dehydrated Escherichia coli and the gilded one. At last, the methods of coating material and coating film thickness were expounded. [Result] The emitted electron from the gun of SEM accumulated onto the regions of sample's surfaces, thus producing glow discharge singed the sample and brought about sparkles in the image. [Conclusion] Glow discharge produced by the electron accumulated on the surfaces of sample can singe the sample, and make the image obscure.%[目的]为利用扫描电镜进行科学研究提供参考与借鉴.[方法]以脱水干燥的大肠杆菌为材料,对其不镀金在扫描电镜下进行观察,并与镀金样品图像进行对比.最后阐述了选择不同样品的镀膜材料与镀膜厚度的方法.[结果]未镀金的样品图片亮暗不均,局部有闪烁亮斑,且随着观察时间的延长,样品逐渐被热电子烤焦.[结论]样品不镀金,发射电子会损伤样品,图像清晰度比镀金样品的差.
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