佳木斯台形变观测对东北地区几次浅震“场兆”异常的探讨

大地震在主破裂前往往行成地壳变形,高应力作用下进入峰值后的变形阶段,反映到地倾斜观测日均值曲线上,表现为固体潮形变趋势异常,这些异常能否指示远距离的地震,近年来不少研究者发现,远场前兆往往出现在对应力、应变变化反应灵敏的特殊构造部位。佳木斯台可能处于这种特殊的构造部位,对东北地区浅源地震短期前兆异常“场兆”的趋势性变化具有一定的意义。     

Comparison of Fe(VI) (FeO4(2-)) and ozone in inactivating Bacillus subtilis spores

The protozoan parasites such as Cryptosporidiumparvum and Giardialamblia have been recognized as a frequent cause of recent waterborne disease outbreaks because of their strong resistance against chlorine disinfection. In this study, ozone and Fe(VI) (i.e., FeO(4)(2-)) were compared in terms of inactivation efficiency for Bacillus subtilis spores which are commonly utilized as an indicator of protozoan pathogens. Both oxidants highly depended on water pH and temperature in the spore inactivation. Since redox potential of Fe(VI) is almost the same as that of ozone, spore inactivation efficiency of Fe(VI) was expected to be similar with that of ozone. However, it was found that ozone was definitely superior over Fe(VI): at pH 7 and 20°C, ozone with the product of concentration×contact time (CˉT) of 10mgL(-1)min inactivate the spores more than 99.9% within 10min, while Fe(VI) with CˉT of 30mgL(-1) min could inactivate 90% spores. The large difference between ozone and Fe(VI) in spore inactivation was attributed mainly to Fe(III) produced from Fe(VI) decomposition at the spore coat layer which might coagulate spores and make it difficult for free Fe(VI) to attack live spores.