pH玻璃电极的现状与发展

对pH玻璃电极的结构、原理以及特性进行了综述.与液体充填式玻璃电极比较,固体接触式pH玻璃电极有明显的优点.叙述了固体接触式pH玻璃电极膜的成分及其响应机理,并指出固体接触式pH玻璃电极的发展方向.     

Kinetic investigation of the chlorine reduction reaction on electrochemically oxidised ruthenium

The rate and mechanism of the electroreduction of chlorine on electrooxidised ruthenium has been investigated with focus on the effect of solution pH. Current/potential curves for the reduction process in solutions with constant chloride concentration of 1.0 mol dm⁻³ and varying H⁺ concentration have been obtained with the use of the rotating disk electrode technique (RDE). It was found that the chlorine reduction rate is highly inhibited in solutions with high H⁺ concentrations and that it can be satisfactorily described by the Erenburg mechanism, previously suggested for the chlorine evolution on RuO₂ and RTO. The expression of the kinetic current as a function of chlorine and H⁺ concentration was obtained by solving the elementary rate equations of the kinetic mechanism. The kinetic constants obtained from the correlation of the kinetic current expression to the experimental data were used to simulate the dependence of the surface coverages and elementary reaction rates on overpotential.     

过氧化氢处理河流着生刚毛藻的效果研究

以深圳市某河流为研究对象,分析了投加H2O2对刚毛藻生物量的控制效果及其对水体p H、溶解氧、氨氮和总磷的影响。结果表明:H2O2≥1.25 mol/L时能有效抑制刚毛藻生长,使藻类光合活性在10 min内从5.8降低到0,叶绿素浓度在30 min内从5.8 mg/L降低至0.2 mg/L。现场试验投加H2O2处理河流水体中刚毛藻14 d内,藻类生物量、光合活性和叶绿素浓度降幅均高于90%。加药1 h后,河流p H值由原来的9.21~9.74迅速降低至8.23~8.80,14 d内保持在9以下。河流溶解氧、氨氮、总磷和H2O2残留浓度在除藻过程中存在变化,但是1 d后会迅速恢复至加药前水平。投加H2O2是一种有效、无污染的应急去除河流着生刚毛藻的方法。     

Mechanistic investigation of hydrogen-enhanced anodic dissolution of X-70 pipe steel and its implication on near-neutral pH SCC of pipelines

The effects of hydrogen-charging on anodic dissolution of pipe steel under near-neutral pH condition were studied by electrochemical techniques. Hydrogen-charging enhances the anodic dissolution rate of the steel. The hydrogen-enhanced dissolution increases with increasing charging current density. The hydrogen effect is attributed to the alteration of chemical potential and exchange current density of steel. Hydrogen-charging affects the corrosion process of the steel. In particular, at a high charging current density, a layer of corrosion product forms on the electrode surface to change corrosion potential and interfacial double-charge layer capacitance as well as charge-transfer resistance. The hydrogen effect factor for enhanced anodic dissolution of steel at an anodic potential of −0.4 V (SCE) is 1.53 only. Hydrogen-enhanced anodic dissolution of steel by itself may not be the major factor contributing to the high rate of crack growth in pipe steel in near-neutral pH electrolyte. A further investigation of the synergistic effect of hydrogen and stress on dissolution at the crack-tip is essential to determine the mechanism of near-neutral pH stress corrosion cracking of pipelines.     

乙炔清净废水再利用研究

本文主要是关注乙炔清净废水循环利用的问题,考察了废次钠液温度、新次钠液有效氯含量,以及pH值等因素对新、废次钠液混合的影响。发现废次钠液温度、新次钠液有效氯含量影响甚微,pH值有较大影响。控制pH值在5.5以上,循环利用废次钠液是可行的。     

VxWorks下MPC8270可加载串口驱动设计

以基于MPC8270串口驱动为例,分析了VxWorks下串口驱动的层次和机理,研究了ttyDrv驱动和MPC8270的SCC接口的工作原理。通过对可加载串口通信驱动程序的实际编写,详细描述了MPC8270体系结构微处理器的串口驱动程序设计基本方法、步骤,实现了串口驱动程序与系统内核启动的分离。     

Effect of pH on a gossypol complex with phospholipids: Gossypol-PE

PE, one of the major phospholipids in oilseed soapstock, may react with gossypol to form Schiff bases. PE amounts to 20–30% of the phosphorus compounds in soap-stock. In this report, the dependence on pH of the Schiff base products between PE and gossypol was investigated using a spectrophotometer, an HPLC equipped with an ELSD, and an LC-MS system. We observed that at pH 7 the Schiff reaction product and reactants were clearly detected by ELSD, absorption, and LC-MS spectra. The absorption spectra displayed the characteristic peak for the Schiff bases around 430–440 nm. The absorption spectra also indicated that the reaction was pH dependent. The reaction temperatures were 60 and 90°C. The LC-MS spectra supported the formation of Schiff bases as well as methyl ether derivatives of gossypol in alcohol at the elevated temperatures. The implications of these experimental findings are presented in this paper.     

含氰污水处理工程设计体会

龙泉金矿在全泥氰化提金过程中产生含氰化物１７４．７６ｍｇ／Ｌ的洗涤废水，通过碱式氯化法处理后，再由渣浆泵送入尾矿库进行自然净化作用，污水得到进一步净化，尾矿库溢流废水氰化物浓度低于０．５ｍｇ／Ｌ，废水排入小梅溪后，下游第一个居民取水点氰化物浓度低于０．００４ｍｇ／Ｌ，达到了国家规定的标准。     

9-蒽甲酸/卟啉钯衍生物的pH响应上转换性能

以9-蒽甲酸(9-ACA)为发光剂,八乙基卟啉钯(Pd OEP)为光敏剂,在二者最佳配比〔n(9-ACA)∶n(Pd OEP)=80∶1〕下,构建了对溶液中氢离子和氢氧根离子具备灵敏响应性的上转换发光体系9-ACA/PdOEP。当pH处于4～8以及8～11时,上转换发光强度均与pH呈现良好的线性关系。参比实验中,单一组分9-ACA本身的荧光强度与pH没有呈现线性关系,证明了9-ACA/Pd OEP体系对于pH的宽范围响应来源于光敏剂与发光剂之间的三线态-三线态能量转移(TTET)过程。     

Fate of nitrogen fertilizer applied to lowland rice on a Sulfic Tropaquept

A field experiment was conducted on an acid sulfate soil in Thailand to determine the effect of N fertilization practices on the fate of fertilizer-N and yield of lowland rice (Oryza sativa L.). A delayed broadcast application of ammonium phosphate sulfate (16-20-0) or urea was compared with basal incorporation of urea, deep placement of urea as urea supergranules (USG), and amendment of urea with a urease inhibitor. Deep placement of urea as USG significantly reduced floodwater urea- and ammoniacal-N concentrations following N application but did not reduce N loss, as determined from an¹⁵N balance, in this experiment where runoff loss was prevented. The urease inhibitor, phenyl phosphorodiamidate (PPD), had little effect on floodwater urea- and ammoniacal-N, and it did not reduce N loss. The floodwater pH never exceeded 4.5 in the 7 days following the first N applications, and application of 16-20-0 reduced floodwater pH by 0.1 to 0.3 units below the no-N control. The low floodwater pH indicated that ammonia volatilization was unimportant for all the N fertilization practices. Floodwater ammoniacal-N concentrations following application of urea or 16-20-0 were greater on this Sulfic Tropaquept than on an Andaqueptic Haplaquoll with near neutral pH and alkaline floodwater. The prolonged, high floodwater N concentrations on this Sulfic Tropaquept suggested that runoff loss of applied N might be a potentially serious problem when heavy rainfall or poor water control follow N fertilization. The unaccounted-for¹⁵N in the¹⁵N balances, which presumably represented gaseous N losses, ranged from 20 to 26% of the applied N and was unaffected by urea fertilization practice. Grain yield and N uptake were significantly increased with applied N, but grain yield was not significantly affected by urea fertilization practice. Yield was significantly lower (P = 0.05) for 16-20-0 than for urea; however, this difference in yield might be due to later application of P and hence delayed availability of P in the 16-20-0 treatment.