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HPLC测定大气中的光气 总被引:1,自引:0,他引:1
报道了用0.25%的苯胺溶液吸收大气中的光气,所形成的1,3-二苯基脲衍生物以高效液相色谱分析。方法回收率为98.1% ̄100.8%,最低检出浓度为1.7×10^-4mg/m^3,线性范围为0.1 ̄340ng,相对标准偏差为1.23%。 相似文献
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高锰酸钾去除水中TCE的研究 总被引:6,自引:0,他引:6
以水中常见的氯代烃污染物三氯乙烯(TCE)为目标污染物,以自制的高锰酸钾溶液为氧化剂,探讨了不同条件下高锰酸钾对TCE的去除效果.结果表明,在30℃、高锰酸钾浓度为0.276 g.L-1的条件下,反应时间为30 min时,TCE的去除率就可达到100%.高锰酸钾对TCE的去除符合一级反应动力学方程,速率常数为0.142 9 min-1,半衰期t1/2为4.85 min.TCE的去除速率随高锰酸钾浓度的增大而增大并呈线性关系,随反应温度的升高而增大,受pH值和离子强度的影响较小. 相似文献
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An analysis of multiple species of Australian gall-inducing thrips with soldiers reveals a significant negative correlation between the size of gall produced and the reproductive division of labour. This correlation suggests that the evolution of smaller galls limited the available space and feeding sites for the offspring of female soldiers, and was a major factor that led to the evolution of an altruistic caste in the gall-inducers. We argue that high levels of inbreeding by singly mated foundresses and incestuous mating by her soldier offspring are key to this evolutionary relationship because they make the relatedness of a female soldier to her daughters and sisters approximately equal. Evidence that relatedness plays an important role is strengthened by the observation of outbred multiply mated foundresses and unbiased sex ratio of dispersers in Oncothrips waterhousei, and the inference that both gall volume and skew decreased along this lineage. 相似文献
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生物技术处理废水的研究进展 总被引:1,自引:0,他引:1
随着经济的发展和人民生活水平的提高,所排放的废水日益增多,造成的环境危害也日趋严重。采用生物技术处理废水具有许多明显的优点。本文详细介绍了生物技术在废水处理中的应用进展及前沿动态。 相似文献
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用GC-ECD测定水中痕量溴酸根的方法 总被引:2,自引:1,他引:1
研究了用GC-ECD测定水中痕量溴酸盐浓度的方法,优化了用工程丙酮作溴酸根衍生化试剂的反应条件.在最佳衍生反应条件下、溴酸根浓度为3.8~92 μg·L-1范围内,溴酸根浓度和相应溴代衍生物的峰面积有良好的线性关系(R2=0.9954).本方法的检出限为0.75 μg·L-1,测定系列浓度溴酸根水溶液的相对偏差(RSD)均小于5%,样品加标平均回收率为105.1%~107.6%.在正常臭氧氧化时间内测定臭氧氧化后的过滤水中的溴酸根浓度时,只要臭氧投量与TOC比值大于0.8 mg·mg-1,溴酸根的测定就不受本底天然有机物的影响. 相似文献
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Tannins (hydrolyzable and condensed) are water-soluble polyphenolic compounds that exert antinutritional effects on ruminants by forming complexes with dietary proteins. They limit nitrogen supply to animals, besides inhibiting the growth and activity of ruminal microflora. However, some gastrointestinal microbes are able to break tannin–protein complexes while preferentially degrading hydrolyzable tannins (HTs). Streptococcus gallolyticus, Lonepinella koalarum and Selenomonas ruminantium are the dominant bacterial species that have the ability to degrade HTs. These tanninolytic microorganisms possess tannin-degrading ability and have developed certain mechanisms to tolerate tannins in feeds. Hence, selection of efficient tanninolytic microbes and transinoculation among animals for long-term benefits become areas of intensive interest. Here, we review the effects of tannins on ruminants, the existence and significance of tannin-degrading microorganisms in diverse groups of animals and the mechanisms that tannin-degrading microorganisms have developed to counter the toxic effects of tannin. 相似文献
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聚合酶链式反应,即PCR(polymerase chain reaction)技术,是一种快速扩增DNA或cDNA序列的方法.水环境中的轮状病毒是导致世界范围内婴幼儿腹泻的主要原因,严重危害着水质安全和人类健康.建立和完善水中轮状病毒灵敏、快速的检测方法对预防和控制水体疾病的暴发具有重要的意义.随着分子生物学技术的发展,PCR及其衍生技术因其具有高度灵敏性、特异性和准确性等特点,成为检测水中轮状病毒最常用的方法.本文综述了利用RCR及其衍生技术,包括逆转录聚合酶链式反应、逆转录半巢式和巢式聚合酶链式反应、多重逆转录聚合酶链式反应、免疫聚合酶链式反应、与免疫磁珠分离相结合的聚合酶链式反应、与细胞培养相结合的聚合酶链式反应及实时定量聚合酶链式反应等,检测水环境中轮状病毒的研究进展,并分析了这些PCR技术在检测水环境中轮状病毒时存在的问题及其应用前景. 相似文献
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CAST工艺在制革废水处理中的应用 总被引:1,自引:0,他引:1
皮革生产企业由于污染严重,污水处理工艺简单、设备落后,最终出水各项指标超标,对环境造成严重污染。CAST工艺处理制革废水,反应条件在缺氧和厌氧之间变化,活性污泥通过酶的作用,不断经历高负荷的基质积累和低负荷的基质降解过程,迅速吸附降解污水中大部分可溶性有机物,抑制丝状菌的生长,有效地防止污泥膨胀,并达到脱氮、除磷的目的。运行结果表明,当进水BOD5为960~1250 mg/l,CODcr为2250~2780mg/l,出水达到《污水综合排放标准》(GB8978-1996)二级标准。 相似文献
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流动注射分析测定饮用水中痕量挥发酚 总被引:3,自引:0,他引:3
采用流动注射分析法(FIA),利用先进技术计算机软件自动控制标准系列配制、取样、前处理、数据报告等。结果准确、精密、快速、灵敏、杂质干扰少,用于水中酚测定,结果满意。 相似文献
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The aim of this study was to assess the value of ultrasonographic evaluation in predicting abnormal karyotypes in fetuses with omphalocele. Forty fetuses with antenatally diagnosed omphalocele and available karyotype results were reviewed. Ultrasound evaluation included herniation contents and size, and the detection of other anomalies. Nine of 40 consecutive fetuses had abnormal karyotypes: trisomy 18 (n = 5), trisomy 13 (n = 3), 47,XXX (n = 1). Only 1/25 with an extracorporeal liver versus 8/15 with an intracorporeal liver had abnormal chromosomes [P = 0·0006, RR = 0·14 (0·02 < RR <0·9)]. Small defects (<3 cm) were associated with abnormal karyotypes [P = 0·01, RR = 4·7 (1·4<RR <15·6)]. Finding concurrent malformations was highly associated with chromosomal anomalies [P = 0·00004, RR = 4·4 (2·3 < RR < 8·5)]. The presence of associated malformations, an intracorporeal liver, and a small herniation size are highly suggestive of an associated abnormal karyotype. 相似文献
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IntroductionIodineisanessentialtraceelementcomposingthyroxinthatisofgreatimportanceforthegrowthofhumanbody.Ithasbeenknownthatthedeficiencyofiodineisamajorcauseforanimpedimentofbrainpower.Duringthefetusandbabygrowing,ifsuppliedadeficientiodine,theywil… 相似文献
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络合铜废水预处理技术探讨 总被引:8,自引:0,他引:8
采用H2O2/Fe^2 构成的氧化体系对络合废水进行破络后,再采用常规的物理化学处理方法进行处理,达到将络合重金属离子去除及降低CODcr的目的。实验分析了影响H202/Fe^2 氧化体系破络反应的各种因素:H202投加量、FeSO4投加量、pH值、氧化反应时间,最后总结出该反应的最佳条件:H2O2/CODcr=2.0、FeSO4投加量10g/1、pH=3、反应时间lh。实验中的络合铜废水是源于某线路板厂家电镀沉铜车间排放的含EDTA络合铜的废水。 相似文献
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水中磷酸盐含量往往需要现场即时测定。通过研制一种测试管 ,从而能简便、快速的现场测定水中的磷酸盐。化学法测定时间需要 3~ 5h ,而该测试管法仅需 2~ 5min。分析成本大为降低 相似文献