通过X射线衍射和扫描电镜对国内外铬酸镧电热元件的结构特征进行了分析，利用定量金相截线法对试样的晶粒尺寸分布进行了统计。
The structure of internal and Japan ones were studied by X ray and SEM. The grain distribution was statistically measured by quantitative metallography method.
探讨了截线抽样法用于浅水型淡水湖泊调查的可行性和有效性以及要注意的问题。
Feasibility, validity and other problems of line transect survey method in shallow fresh water lake were also discussed.
对坐标转换的基本概念和基本公式做了研究，给出了法截线曲率半径、子午线弧长和底点纬度的解算公式。
Research the basal concepts and formulas of coordinate conversion, the formulas of the radius of curvature in a normal section, the meridional length and the latitude of pedal are given.
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