Methods By using the principle of determination of dissolved oxygen demand, the variation of the oxygen demand of the snail in different number, density and time was determined, and the effect of the selective number and time was evaluated. 方法根据水质溶解氧测定的原理,测定钉螺在不同数量/密度、不同时间情况下,在水中耗氧量的变化情况,评价耗氧测定钉螺适宜数选择性试验和耗氧测定适宜时间选择性试验的效果。
Ozonization reduced the contents of total dissolved solids and oxygen demand, and decomposed some reductive contaminants such as ammonia, cyanide and phenols. 臭氧处理使溶解性总固体含量和耗氧量略有减少,对矿泉水的一些还原性污染物如氨、氰化物和酚类化合物有不同程度的降低;
The test utilizes the relation curve of air-water ratio and dissolved oxygen to deduce creek experiential oxygen demand. 采用气水比与溶解氧关系的曲线推求河道供氧量。
Three kinds of portable environmental monitoring instruments are reported for in situ analysis of pesticide residues, dissolved oxygen ( DO ) and chemical oxygen demand ( COD ). 报道了3种自行研制的分别用于农药残毒、溶解氧(DO)及化学需氧量(COD)现场分析的手持式环境检测仪。
COD was dominated by the dissolved matters, even though the variant amount of suspended solid resulted in the deviation of chemical oxygen demand ( COD ) of wastewater from the different tanks. 废水化学耗氧量变化受到其中悬浮物的影响,但化学耗氧量主要来源是水体中的溶解态物质;