CaCu3Ti4O12, an efficient catalyst for ibuprofen removal by activation of peroxymonosulfate under visible-light irradiation

Environmental Chemistry Letters - Contamination of waters by pharmaceuticals is a major health issue. Therefore, there is a need for efficient techniques to remove pharmaceutical pollutants. Here,...     

Oceanic diffusion and the pelagic insects Halobates spp. (Gerridae: Hemiptera)

Five pelagic Halobates species occupy a vast area from 40^∘ north to 40^∘ south in the three major oceans. Oceanic diffusion, constantly acting to disperse these insects, must be an important factor in determining their life history and distribution. We investigated the effects of oceanic diffusion on the following aspects of these insects. (1) The estimated radius of a patch of Halobates could be expanded by oceanic diffusion alone from an initial point of origin to 1250 km in 60 d. This distance is about 1/12 of the maximum distributional range of H. micans in the Pacific Ocean. Mutual encounter rates due to oceanic turbulence could be as high as 11 d⁻¹ even at low population densities (100 ind km⁻²). This suggests that individuals from their original habitat could find mates even when they had been carried a long distance. Thus, extensive gene mixing may occur over the whole range of a species' distribution. (2)␣Estimated growth rates are rather low (0.0026 to 0.0079 d⁻¹) compared with those of other insects. However, they are offset by a long life span (over 90 d) and an extended oviposition period (perhaps over 2␣months). Thus, pelagic Halobates spp. appear to have adopted a strategy of slow growth and prolonged longevity to cope with living in an unstable physical environment that is constantly disturbed by storms and winds. Received: 5 February 1995 / Accepted: 30 October 1997     

浸水条件下环氧微表处与沥青路面层间抗剪性能的试验研究∗

微表处在工程应用过程中受水与车辆荷载作用,容易产生推移或整片剥落。为此,在微表处中添加适量不同种类的水性环氧树脂(Water-borne Epoxy Resin,WER)形成环氧微表处,通过拉伸试验和自主设计的45°斜剪试验,研究WER对环氧微表处在浸水条件下层间抗剪性能的影响。试验结果表明:胶结料在掺入刚性较大的WER后,随浸水时间增加,胶结料塑性变形能力削弱,弹塑性阶段与塑性阶段减短,脆性增加,而掺加柔性的WER,塑性阶段持续时间较长;浸水状态下,环氧微表处与沥青路面的层间抗剪强度影响因素主次顺序为油石比WER掺量WER掺加方式,而切向变形率的影响因素主次顺序为WER掺量WER掺加方式油石比。在工程应用中,建议采用油石比7%、WER掺量8%～12%且将环氧树脂与固化剂预先调和后加入水中,然后与集料进行拌合。     

Photodegradation of Benthiocarb

The photodegradation of ¹⁴C-benthiocarb in water, on a glass surface, on soil and silica gel TLC plates was studied. the study was designed to obtain some information of its dissipation and photodegradation under various laboratory conditions. Benthiocarb degrades readily when exposed to either sunlight or UV light (254 nm). However, it is degraded much faster by UV light than by sunlight. Also, benthiocarb decomposes faster in water or on a glass surface or silica gel surface than on a soil surface. the half-life of benthiocarb exposed to UV light was: 1 hr on glass surface; 1.5 hrs in water; 2 hrs on silica gel TLC plate; 20 hrs on soil TLC plate. Benthiocarb in water, and exposed to sunlight, had a half-life of approximately 3 days. the following major photodegradation products were identified: 4-chlorobenzyl alcohol; 4-chlorobenzaldehyde; 4-chlorobenzoic acid.     

便携式ＧＣ-ＭＳ测定空气中有毒物质的应用

文章介绍了便携式气相色谱-质谱联用仪(Gas Chromatograph-Mass Spectrometer,GC-MS)的结构原理,结合应急监测的需要,说明了仪器性能参数与分析操作模式,探讨了标准曲线的建立与验证。通过仪器的实际应用,指出该仪器能够解决应急监测中目前存在的对有机污染物难以快速定性、定量的问题。利用捕集浓缩器富集待测定空气中挥发性有机化合物(VOCs),可迅速判断出气体样品中的挥发性有机化合物组分,给出定量测定结果。并根据日常使用情况,总结了便携式GC-MS性能特点。     

Ti-SnO_2电解快速去除熄焦循环水中COD

以Ti-SnO2电极作为阴阳极,利用电解池对焦化厂熄焦循环水COD进行去除。极板间距为1 cm,6个极片组成电解池,处理熄焦循环水。实验结果表明:废水被稀释1倍时,污染物的浓度有利于COD的去除;最佳去除条件是电解电压为11 V,p H值为6;当电解时间为0.5 h时,废水的COD由230 mg/L降低到138 mg/L,满足《炼焦化学工业污染物排放标准》中规定的焦化生产废水经处理后用于熄焦时对COD的要求;电解时间增加到2 h,废水的COD由230 mg/L降低到66 mg/L,去除率达到80%。     

新东方教学管理应用于高职英语教学的研究

高职教育是我国高等教育体系中不可或缺的部分,其中英语教学面临学生基础差,缺乏学习动机和兴趣且存在两级分化,课堂秩序混乱的局面。教师在教学管理中缺乏方法,缺乏成就感,教改和创新动力不足,且高职院校师资构成不合理,教师缺乏提升进修渠道。以新东方为代表的民办教育中,学生学习兴趣浓厚,出勤率高,课堂秩序井然。教师提升手段较多,激励机制较为完整,师资构成更为合理,教学效率高。通过高职和新东方教学管理的对比,探索高职英语教学的解困之道,以推进高职英语教学向更好的方向发展。