微生物碱性蛋白酶研究进展

本文对微生物碱性蛋白酶的产生菌,碱性蛋白酶的应用、结构及性质,高产工程菌的选育技术等方面的研究进展进行了概述。     

Initial pH influences in-batch hydrogen production from scotta permeate

We studied the influence of initial pH on hydrogen (H₂) production using permeate from scotta (a partially deproteinized cheese whey from ricotta production) as substrate (51 g L^?1 lactose). Dark fermentation was carried out at 35 °C in laboratory batch reactors, in an unbuffered system. Hydrogen production and metabolite (volatile fatty acids, ethanol, and lactic acid) evolution during a 96-h period were monitored in reactors with initial pH varying in the range 4–10. In all reactors, H₂ production started only when pH fell below 6. However, it was much higher (+31%) in the reactors with initial alkaline pH. We conclude that H₂ production occurs only at acidic pH values, but initial alkaline pH values increase the overall H₂ production in dark fermentation of lactose-rich substrates.     

Chitosan-Modified Poly(2,6-dimethyl-1,4-phenylene Oxide) for Anion-Exchange Membrane in Fuel Cell Technology

A series of cross-linking chitosan-modified quaternary ammonium poly(2,6-dimethyl-1,4-phenylene oxide)s membranes (CS-QAPPO) were prepared by the Menshutkin reaction. The mechanical property, dimensional stability, and alkaline stability of the CS-QAPPO membrane have been impressively improved by introducing CS into PPO backbone. Even the hydroxide conductivity of CS-QAPPO membranes is higher than that of the pristine QAPPO membrane. The 20% chitosan-modified QAPPO membrane shows the best performance, and the hydroxide conductivity is 32 mS cm^?1 at 90°C. The alkaline stability measurements demonstrated excellent chemical stability of the CS-QAPPO membrane in 2?M NaOH solution at room temperature after 2,000?h.     

液体碱性脂肪酶稳定性的化学动力学研究

从多方面考察了碱性有肪酶超滤浓缩液的稳定性，推导出液体碱性脂肪酶失活动力学方程，得到了液体碱脂肪酶的失活级数为１．３６级。     

可充碱锰电池用化学二氧化锰的制备

温度控制在 85～ 95℃ ,在HNO3介质中 ,用KMnO4氧化MnCl2 和Bi(NO3) 3的混合溶液 ,可制得具有良好可充性能的掺铋二氧化锰 (Bi MnO2 ) ,该样品在 9mol/LKOH溶液中有稳定的循环伏安曲线且经X射线衍射分析测得其在不同放电深度均无Mn3O4生成 ,这表明在MnO2 中添加铋可阻止不具有电化学活性的Mn3O4生成 ;用该样品做成的模拟电池做连续充放电实验 ,电极的循环次数由原来的 5～ 6次 ,提高到 60次以上。     

Corrosion of aluminium in the aqueous chemical environment of a loss-of-coolant accident at a nuclear power plant

Aluminium corrosion is a significant concern in the aqueous chemical environment of the reactor containment building following a hypothetical loss-of-coolant accident (LOCA) at a nuclear power plant. Aluminium corrosion may lead to the formation of precipitates that can, in combination with insulation debris, block the recirculation sump screens. This study investigated aluminium corrosion experimentally at both bench and pilot scale under conditions representative of several types of nuclear power plants. Evidence of corrosion was determined using aqueous concentrations measured with inductively-coupled plasma (ICP) spectrometry and surface examinations using scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), X-ray photoelectron spectrometry (XPS), X-ray fluorescence (XRF), and X-ray diffraction (XRD). Corrosion proceeded slowly at pH near 7, but more rapidly at higher pH when the representative pipe insulation material was fibreglass. However, when calcium silicate pipe insulation was introduced into the system, corrosion became insignificant even at pH values near 10. Experimental evidence indicates that the calcium silicate insulation released a significant amount of silicate to the solution. Silicate formed a passivation layer composed of Al₂OSiO₄ with a thickness of more than 10 nm, and this layer effectively inhibited corrosion.     

碱性蚀刻液影响因素的研究

为了确立最佳的碱性CuCl2蚀刻工艺条件,提高工作效率,采用烧杯静态吊片蚀刻法,研究了影响蚀刻速率的因素.主要研究结果如下:1)在蚀刻时间为5min时,单因素试验得出的适宜的工艺范围为:Cu2+的质量浓度约为140～180g/L,Cl-的质量浓度为4.8～6.5mol/L,pH为8.2～9.0,操作温度为48～55℃;2)正交试验结果表明,在Cu2+的质量浓度为160g/L,Cl-的质量浓度为5.5mol/L,pH为8.8,操作温度为50℃时,蚀刻状态最好,静态蚀刻速率可达到5.84μm/min.     

难镀铝材化学镀镍中碱性预镀镍工艺研究

对难镀铝材化学镀镍技术的核心部分,即中间处理工艺中的碱性预镀镍技术进行了深入研究。由正交试验确定了一种性能优异的中等浓度浸锌液。经对比试验,选择出了能与该浸锌处理最佳结合的碱性预镀镍配方及难镀铝材化学镀镍中间处理的最佳工艺条件。     

碱／表面活性剂复合驱油体系与胜利孤东原油间协同效应的研究

考察了碱／非离子表面活性剂ＯＰ１０＋石油磺酸盐Ｃｙ体系与胜利孤东原油及萃取其酸性组分后的剩余油间的动态界面张力特性，发现复合驱油体系中的外加表面活性剂、碱与原油原位生成的表面活性物质之间存在明显的协同效应。这种协同效应对低离子强度下短时间内的界面张力影响较大；外加表面活性剂对高离子强度下长时间的界面张力影响较大。动态界面张力的最低值与界面上各表面活性物质的浓度和比值有着十分重要的关系     

稠油热碱水系统界面张力和乳液特性研究

主要研究了碳酸钠、氢氧化钠、硅酸钠三种碱与稠油的界面张力和碱液-稠油乳状液的特性,讨论了乳状液的驱油机理。结果表明,这三种碱液与稠油的界面张力在一定条件下均能达到10~2mN/m数量级以下;高油水体积比下的碱水-稠油乳液类型由碱浓度决定。