板坯定宽过程狗骨分布的有限元分析

利用有限元方法建立了板坯定宽的有限元模型 ,系统研究了板坯定宽过程中金属的流动规律 ,并模拟了板坯狗骨形成过程。得到狗骨的分布规律 ,对研究板坯定宽有重要指导意义。     

The Determination of Carbonyl Compounds in Ozonated Water by the PFBOA Method

PFBOA, O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine, is excellent as a derivatizing agent in the GC determination of carbonyl compounds in ozonated water samples. Surface and waste waters have been ozonated. The carbonyl ozonation by-products were identified as PFBOA derivatives by gas chromatography-mass spectrometry. The main by-products of ozonation identified were formaldehyde, glyoxal, methylglyoxal, and 13 other compounds. The characteristics of the first three compounds with respect to production and decomposition during ozonation are discussed.     

Ozone Gas Scrubbing for Air-Operated Ozone Generation Systems

In laboratory testing as well as in tests using a semi-technical plant it was found that removal of the gaseous N₂O₅ as a by-product of ozone generation from air can be realized from a chemical point of view by gas scrubbing using treated drinking water, and forming nitric acid. At the same time this measure accomplishes a reduction of the trichloronitromethane (TCNM = chloropicrin) concentration in the treated water from Lake Constance by 30%. Surprisingly it was also found that the material used herein (stainless steel DIN 1.4571) will be attacked under conditions such as these.