The Electron‐Micrographic Structure of Shadow‐Cast Films and Surfaces
The Electron‐Micrographic Structure of Shadow‐Cast Films and Surfaces
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DOI：
10.1063/1.1698244
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发表时间：
1949
影响因子：
3.2
通讯作者：
Robley C. Williams;R. Backus
中科院分区：
文献类型：
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作者：
Robley C. Williams;R. Backus
可以用电子显微镜拍摄的生物物体的尺寸下限，借助于阴影投射，被证明取决于它们可以安装在其上的基底的光滑度，以及它们被遮蔽的薄膜结构的连续性。报道了许多改进现有缺陷的尝试，涉及生产更光滑的基底膜，以及生产用于高效和结构连续性的阴影投射的膜。在生产比通常使用的火棉胶和Formvar膜明显更光滑的可用基底膜方面没有成功。研究发现，这种类型的薄膜的最佳阴影投射材料是铀或氧化铀。当受到偏置束电子枪的电子流的影响时，先前用于预阴影复制过程的金薄膜的严重颗粒化已经得到了验证。试图将颗粒化减少到令人满意的水平，但失败了。
The lower limit of size of biological objects which can be photographed with the electron microscope, by the aid of shadow‐casting, is shown to depend upon the smoothness of substrate upon which they can be mounted, and upon the continuity of structure of the thin films with which they are shadowed. Numerous attempts to improve the existing deficiencies are reported, both with respect to producing smoother substrate films, and to producing films for shadow‐casting of high efficiency and continuity of structure.No success has been encountered in producing a usable substrate film perceptibly smoother than the collodion and Formvar films commonly used. It is found that the best shadow‐casting material for this type of film is uranium or uranium oxide.Verification has been obtained of the severe granulation of gold films previously used in the pre‐shadowed replica process, when subjected to the electron current of a biased‐beam electron gun. Attempts to reduce the granulation to a satisfactory level have fail...