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Researches on Formation of Haloacetic Acids in Chlorination of Drinking Water by a Novel Technique

Chemical Research in Chinese Universities 2004年第3期20卷 285-288页

作者： LIXin RENYue-ming qiangliang-sheng ZHAOHong-bin DepartmentofAppliedChemistry HarbinInstituteofTechnologyHarbin150090P.R.China SchoolofCivilEngineer HarbinInstituteofTechnologyHarbin150090P.R.China

Haloacetic acids(HAAs) are formed during the chlorination of drinking water,which are harmful to people′s health due to their carcinogenic and mutagenic effects. In the present study,a detection method combining methyl tert -butyl ether(MtBE) extraction with acid catalysis and gas chromatography coupled with an electron capture detector(GC/ECD) was developed for determining HAAs. The detection limit of this method(MDL) and relative standard deviation(RSD) were below 0.37 μg/L and 6.2%,respectively. The laboratory chlorination experiments were conducted with the purpose of investigating the influences of reaction time,temperature,UV_ 254 ,bromide and ammonia-nitrogen on the formation of HAAs. The results show that the formation amount of HAAs increases with increasing reaction time and temperature,respectively;and there exists a linear relationship between the formation of HAAs and UV_ 254 . The formation amount of HAAs decreases first and then increases as the bromide ion concentration increases,and adding NH +_4 is a possible way to control the formation of HAAs.

关键词： Haloacetic acid(HAA) Drinking water Chlorination

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Formation Enthalpy Calculation of Oxygen Vacancy Defect in Doped Lithium Niobate Crystals

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Chemical Research in Chinese Universities 2004年第1期20卷 65-67页

作者： qiangliang-sheng LIYao TANGDong-yan XUChong-quan WEIYong-de DepartmentofAppliedChemistry HarbinInstituteofTechnologyHarbin150001P.R.China CenterforCompositeMaterials HarbinInstituteofTechnologyHarbin150001P.R.China

The relationship between temperature and oxygen vacancy concentration is deduced in this paper. Based on the data of thermal weight-loss experiment, the formation enthalpies of congruent and several doped LN crystals have been calculated. It was found that the formation enthalpy of oxygen vacancies can be decreased evidently by doping valence-changeable ions. The experimental results were discussed and a new reduction process of the photorefractive LN crystal at a relatively low temperature was proposed, and the reduced crystals showed a good effect in practical use.

关键词： Formation enthalpy calculation Oxygen vacancy defect Doped lithium niobate crystal

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