单扫描示波极谱法测定环境水样中马拉硫磷残留量

本文拟定了一种测定马拉硫磷残留量的极谱法，在０．１ｍｏｌ／ＬＮａＯＨ基底溶液中，用单扫描示波极谱仪制作其阴极化一阶导数极谱曲线，峰电位Ｅｐ为－０．４２Ｖ（ｖｓ．ＳＣＥ），在０．０８－０．５μｇ／ｍｌ范围内ｉ＇ｐ与浓度间呈线性关系。讨论了一些常见农药及离子的干扰情况，以及影响溶出峰电流的因素。方法应用于环境水样中马拉硫磷残留量的测定。变异系数在１０％以内。     

硝酸及氯离子对高温硝酸铵水溶液热危险性的影响研究

国内外学者对硝酸铵的危险性进行了大量的研究,而对其水溶液的危险性至今开展不多。笔者采用差示扫描量热仪(DSC)及全自动反应量热仪(RC1e)对高温状态下的硝酸铵水溶液的热分解危险性、杂质离子对其稳定性的影响进行了研究。纯硝酸铵和90%硝酸铵水溶液的DSC实验表明,90%硝酸铵溶液和分析纯硝酸铵具有相似的热爆炸危险;90%硝酸铵水溶液在140~180℃之间的RC1e试验表明:硝酸或氯离子单独存在时,对硝酸铵分解都有不同程度的抑制作用,而同时存在时则大大降低体系的热稳定性。该结果对保障硝酸铵在生产、使用过程中的安全具有重要的参考价值。     

国外职业安全扫描

英国:煤矿严格管理换来安全英国国家煤炭博物馆大厅的墙上写着这样一句话:矿工曾是这个国家最危险的职业之一,火灾、水灾、爆炸和塌方随时都在威胁着他们的安全。博物馆的资料室给出了这样一组数字:19世纪60年代,英国每年每200名煤矿矿工中就有1人死亡;20世纪初,每600人中有1人死亡;20世纪50年代,每1000人中有1人死亡。问及英国煤矿现在的安全情况,恰好前来博物馆参观的一位老矿工说:“现在,英国煤矿每年死亡的矿工人数为零。2005年为零,2004年为零,2003年为零,2002年为零……”     

环球扫描

<正>污染引发心脏疾病美国心脏学会的研究称,工业、交通和发电带来的污染提升了中风和心脏病的发作几率,人们应该尽量避免吸入烟雾。研究显示,化石燃料比如汽油、煤和石油等燃烧产生的微颗粒物质是罪魁祸首。研究报告的第一作者,美国密歇根大学的罗伯特·布鲁克教授称:对易受外界因素影响的个人来说,持续吸入几小时或者几天的微颗粒物质,会直接增加其患病几率。一定数量的微小颗粒或者化     

环球扫描

为绿色飞行而战 欧盟新排放标准规定,凡是有飞机在欧洲降落的航空公司均需向欧盟提交有关如何遵守排放标准的计划书。美国航空运输协会环境事务副总裁南希·扬说：“我们反对这一计划的态度非常坚决。”她同时指出,购买排放许可将使航空公司缺乏足够的资金来研发减排的创新技术。     

环球扫描

皮特·扎赫勒：拯救阿富汗野生动物 阿富汗80％的野生动物是直接依靠自然资源生存的。如果没有可持续性的自然资源,它们就无法存活。因此自然保护是阿富汗重建的核心支柱。     

Morphology of single inhalable particle inside public transit biodiesel fueled bus

In an urban-transit bus,fueled by biodiesel in Toledo,Ohio,single inhalable particle samples in October 2008 were collected and detected by scanning electron microscopy and energy dispersive X-ray spectrometry(SEM/EDS).Particle size analysis found bimodal distribution at 0.2 and 0.5 μm.The particle morphology was characterized by 14 different shape clusters:square,pentagon,hexagon,heptagon,octagon,nonagon,decagon,agglomerate,sphere,triangle,oblong,strip,line or stick,and unknown,by quantitative order.The square particles were common in the samples.Round and triangle particles are more,and pentagon,hexagon,heptagon,octagon,nonagon,decagon,strip,line or sticks are less.Agglomerate particles were found in abundance.The surface of most particles was coarse with a fractal edge that can provide a suitable chemical reaction bed in the polluted atmospheric environment.The three sorts of surface patterns of squares were smooth,semi-smooth,and coarse.The three sorts of square surface patterns represented the morphological characteristics of single inhalable particles in the air inside the bus in Toledo.The size and shape distribution results were compared to those obtained for a bus using ultra low sulfur diesel.     

Paper sludge as a feasible soil amendment for the immobilization of Pb^2＋

The possibility of amending Pb 2+ contaminated soil (S) with paper sludge (P) was investigated through adsorption and desorption experiments. The adsorption process of Pb 2+ in soil containing paper sludge (SP) could be well described by pseudo second-order kinetic model and the Langmuir isotherm model. After P addition, the equilibrium time decreased greatly (from 28 to 8 hr) and the Pb 2+ maximum adsorbed amount (Q max ) increased by a factor of more than three to 102.04 mg/g. Q max reached its maximum as...     

长安地裂缝带黄土的微观结构特征研究

以长安地裂缝带黄土为研究对象,通过采取裂缝面上的黄土及未受裂缝影响的原状黄土进行电镜扫描试验,对两者的微观结构特征进行了对比研究,并分析了裂缝带附近黄土物理力学性质变异的原因。结果表明:裂缝面黄土与原状黄土在微观结构上存在显著差别,主要表现为裂缝面黄土颗粒接触类型为面-面接触,具有定向排列现象,颗粒之间孔隙较小、结构致密,并可见明显的擦痕,原状黄土颗粒接触类型则表现为棱-面接触或面-面接触,并发育缝隙状孔隙,总体为镶嵌孔隙结构;两者微观结构的差异表明地裂缝的活动具有剪切滑移特征。     

Photoelectrochemical degradation of Methylene Blue with -PbO2 electrodes driven by visible light irradiation

-PbO2 electrodes were prepared by electro-deposition and characterized by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and linear sweep voltammetry. We confirmed pure -PbO2 crystals were on the electrode and it had a high oxygen evolution potential. The photoactivity and photoelectrochemical (PEC) properties of the -PbO2 electrode were investigated under visible light irradiation ( > 420 nm) for the decolorization of Methylene Blue. Pseudo first-order kinetics parameter (Kapp) for dye decolorization using the -PbO2 electrode achieved 6.71×10?4 min?1 under visible light irradiation, which indicated its excellent visible light-induced photoactivity. The Kapp of the PEC process was as much as 1.41×10?3 min?1 and was 1.71 times that of visible light irradiation or electrolysis even in the presence of the -PbO2 electrode. A significant synergetic effect was observed in the PEC system. We also employed TiO2 modified -PbO2 electrodes in this test, which revealed that the TiO2 immobilized on the -PbO2 electrode inhibited the visible light-induced PEC efficiency despite the amount of TiO2 used for electrode preparation. The -PbO2 electrode was also superior to the dimensionally stable anode (Ti/Ru0:3Ti0:7O2) in visible light-induced photoactivity and PEC efficiency.