Discussion on some shortages of national standards of PVC-U water supply and drainage pipes and pipe fittings;

An assumption on setting up national standard of BB fertilizer based on its developing actualities;

The national standard of determining Ca, Mg and S contents in compound fertilizer;

The processing methods of overburden layer on Mg alloys and the correlative national standards;

Analysis on national standards of reflective membrane and its application at present;

Study on the Determination Method of Molybdenum Quantity in National Standards Molybdenum Ore Concentrate;

Explanation on state standard of Chinese steamed bread based on wheat flour;

Discussion on methyl alcohol & lead in state standard GB2757-1981;

Analyzing the Modification of State Standard"Automatic Rail-weigh Bridges"

Algorithm of intersecting dash dot lines of engineering drawings in accord with GB;

Two ISO standards and three GB standards are introduced.

It cites some errors of weld symbol representation on the production drawings,and compares them with the representation in GB in this paper.

The writer picks up a few imperfections from"General principles of presentation"of the national standard ness of the latest emendation,oppugns seriousness of establishment and emendation,and contributes a few viable opinions.

Therefore the dimensions drawing in this way cant conform with the National Standard.

This paper discusses the table in mechanical drawing according with the national standard in using AUTOCAD, and introduces the realization methods in the dimension, the tolerance of the figure and place and non 1:1 scale.