钢铁常温发黑

分析了钢铁常温发黑过程的成膜机理。提出了直接成膜的可能性。测定了氧化剂还原的动电位曲线和发黑过程的电位-时间曲线。得到了良好的实践结果。     

磺甲基酚醛树脂在水中的分散特性

考察了SPF(磺甲基酚醛树脂)在去离子水、氯化钠溶液和不同pH溶液中的分散特性,并对分散体系浊度变化规律、分子聚集体尺度和Zeta电位进行了测定。研究结果表明:SPF在去离子水中具有良好的分散稳定性,分子聚集体粒径较小;在低氯化钠浓度下,体系稳定性较好,浊度不随时间增加;盐浓度增加后,Zeta电位绝对值减小,体系失去分散稳定性,浊度随时间显著增加;当pH大于1.95时,体系分散稳定性较好,随着pH的降低,Zeta电位绝对值和体系分散稳定性降低,而浊度随着时间增加。     

不锈钢着色工艺研究

通过正交试验研究了不锈钢着色液配方、温度、时间、电极电位对着色的影响，优化了着色工艺，获得了电极电位与颜色的良好对应关系。测试了着色膜的耐磨性、耐蚀性、变形加工性能，分析了添加剂对不锈钢着色的影响。所得膜层颜色均匀，耐磨性、耐蚀性、变形加工性能良好，工艺维护简单。     

开路电位测量法评价镀锌层三价铬钝化膜的耐蚀性

用钝化剂TRI-V 120、TRI-V 121和SpectraMATETM 25分别对碱性无氰镀锌层进行钝化,考察了钝化层在不同pH的1%(质量分数)NaCl溶液中的开路电位随时间的变化.结果表明,开路电位变化受溶液pH的影响.在pH=3时,镀锌钝化层的开路电位随时间呈规律性变化:开始电位较高,反映了完整钝化层的电极电位;随后逐渐变负,反映了钝化膜的溶解过程;最后处在锌的电极电位范围,反映了钝化膜已经完全溶解.对比盐雾试验结果后发现,从钝化膜电位变化到锌电极电位所需的时间能够反映钝化膜的稳定性,即时间越长,耐蚀性能越好.因此,开路电位测量法能够快速评价镀锌钝化层的耐蚀性.     

电解清除氧化皮的304不锈钢盘条耐蚀性的电化学评价

研究了电解清洗黑色和蓝黑色氧化皮304不锈钢盘条在盐酸和氯化钠介质中的耐蚀性能。动电位极化曲线方法测试了清洗后盘条的耐点蚀性能;恒电位充电曲线研究了不锈钢盘条的时间有效性。结果表明，电解清洗后不锈钢具有良好的耐蚀性。表面电子能谱测试表明清洗后不锈钢表面有显著的Mn元素富集，并探讨了Mn元素富集对耐蚀性的影响。     

氧化物电还原体系银/氯化银参比电极性能研究

参比电极的研究是高温熔盐电化学必不可少的环节之一。以莫来石作为Ag/AgCl电极隔膜材料,制备了可用于在650 ℃的LiCl熔盐体系中开展氧化物电化学还原实验的Ag/AgCl参比电极。采用开路电位法考察了电极活化时间、可逆性、耐极化性、稳定性及重现性等性能。例如,初次使用的参比电极要经过2 h活化才能达到电位稳定。给予微弱电流后参比电极会发生极化,但极化电位基本能在断电后的几分钟内消除。结果表明,莫来石隔膜Ag/AgCl参比电极具有活化时间短、温度对电极可逆性影响小、耐极化性能、电位稳定性、平行性及重现性良好等特点。该参比电极的研制为将来开发性能更加稳定的可用于高温熔盐氧化物电化学还原的参比电极提供了一定的指导意义。     

超级电容器电极材料制备与性能研究

用恒电位沉积法在不锈钢电极上制备了MnO2薄膜,测试了循环伏安曲线及充放电性能。测试结果表明,充放电电压随时间呈线性变化,循环伏安曲线无明显的氧化还原峰,说明制备的MnO2具有良好的电容特性。     

零流电位法的性能及其能斯特响应的研究

探讨了零流电位法的检测原理,并利用一系列不同混合比例的铁氰化钾/亚铁氰化钾溶液考察了零流电位法的性能。实验结果表明:零流电位法具有能斯特响应的性能,同时表现出较高的准确性以及良好的精密度和重现性。     

硅整流式和逆变式的恒电位仪在油田阴保系统中的组合应用

本篇论文根据实际需求,在恒电位仪阴极保护技术分析的基础上,将可控硅式恒电位仪与逆变式恒电位仪通过单片机组合一起,设计和研制开发了联机联调电路,并对新产品在大港油田管道阴极保护系统中的应用情况进行了统计分析,结果表明组合式阴极保护恒电位仪较好的满足了油田阴极保护系统的要求,具有良好的应用前景。     

疏水缔合聚合物对NaCl溶液中低溶解度PF分散特性的影响

为改善LPFR(低溶解度酚醛树脂)在低矿化度水中的分散稳定性,以HAP(疏水缔合聚合物)作为LPFR的稳定剂,并测定了分散体系在去离子水或NaCl溶液中的流体力学直径(Dh)、Zeta电位、浊度及稳定时间。结果表明:当LPFR水溶液浓度为300 mg/L时,LPFR以单分子或较小的分子聚集体形式存在于去离子水中,Zeta电位较高、浊度较小且稳定性良好;加入NaCl后,LPFR形成了较大的分子聚集体,Zeta电位降低、浊度增大且稳定性变差;引入HAP后,LPFR/HAP因疏水缔合作用而形成了Dh较小的复合分子聚集体,其Zeta电位较大,浊度明显降低,稳定性增强;HAP能明显改善LPFR在NaCl溶液中的分散特性及稳定性。     

Unsteady auto-ignition of hydrogen in a perfectly stirred reactor with oscillating residence times

The ignition characteristics of a hydrogen–air mixture in a perfectly stirred reactor (PSR) with an oscillating residence time were investigated numerically. An unsteady numerical algorithm was developed and solved using a stiff-equation solver in order to investigate the unsteady auto-ignition behavior of the fuel/air mixture. The amplitude, frequency, and phase of the residence time oscillations were varied, and the effects on the simulated ignition behavior were recorded. Under small amplitude oscillations of the residence time, once ignited, the temperature in the reactor varied following the phase of the oscillations. Under larger amplitude variations, periodic ignition, and extinction events were observed. A critical frequency was observed, where the ignition delay time became significantly large than at the other frequencies. The existence of this critical frequency was found to depend on the phase of the residence time oscillation, and only occurred when the phase was such that the residence time decreased from the initial conditions. Ignition did not occur for frequencies of the oscillation in the residence time beyond 2.84 kHz, regardless of the phase. The physics of ignition delay for the case where the oscillatory residence time decreased initially could be clarified by investigating the time variation of characteristic chemical times of important reactions to ignition.At low frequencies of the residence time oscillation, similar behavior to that of the steady state was observed. However, the ignition delay time was found to be significantly different at high frequencies, especially for larger amplitude fluctuations in the residence time. Combustion of the fuel/air mixture could be sustained at shorter residence times under the oscillating residence time conditions than under the steady-state conditions. The reaction could not be sustained at high frequencies, and a pulsed-mode flame was observed, where the period of the ignition and extinction events was the same as the period of the oscillations in the residence time.The concentration of free radicals was found to increase with time prior to ignition, and the H radical concentration saturated at a maximum at the ignition time, indicating that the H radical concentration is a good indicator of ignition time under oscillating residence times.     

气液搅拌釜中不同因素对混合时间的影响

在液体石蜡中通入氮气的气液搅拌釜中,通过光差法确定特定混合状态和达到该状态的混合时间,研究了多种因素对气液混合时间的影响。进气流量较小时,随进气流量增加,混合时间明显缩短;但当进气流量达一定值时,混合时间变化很小。比较了12个搅拌桨,转速和进气流量均相同时,6叶大圆盘涡轮桨混合时间最短;列出了4种桨型混合时间的长短顺序。转速和进气流量一定时,用4挡板替换3挡板,混合时间略有缩短。     

Experimental Study on Time Features of Particle Motion in Rotating Drums

Rotating drums are widely used in pharmaceutical industry to coat tablets. The motion of the tablet particle is one of the most important factors affecting coating uniformity. The purpose of the research is to experimentally investigate two important time variables for the coating process, residence time and turnover time, and their dependence on operating parameters (rotation speed and filling degree of the drum). The average residence time was found to decrease with increasing rotation speed and filling degree. The average turnover time was observed to increase approximately linearly with the inverse of the drum speed, but was found to be independent of the filling degree. A dimensionless time variable, the fractional residence time, i.e., the residence time divided by the turnover time, was introduced. Analysis showed that the fractional residence time could be a good indicator of coating uniformity. Results of the present work provide useful information for theoretical modeling which may ultimately serve as a tool for coating optimization.     

煤粒着火及燃烧稳定性

用热天平研究了几种煤焦的化学着火时间，发现与环境温度有较明显的联系，并综合煤粒加热物理着火时间，提出了一个衡量煤在实际锅炉中的燃烧稳定性的影响。     

Liquid-phase mixing in external-loop airlift bioreactors

Mixing time, circulation time and downcomer linear liquid velocity were measured in two sizes of external-loop airlift bioreactors with Newtonian and non-Newtonian fluids. The mixing time increased as a result of an increase of non-Newtonian characteristics. However, the liquid circulation time was affected only slightly by non-Newtonian flow behaviour. A semi-empirical correlation for circulation time in external-loop airlift bioreactors was proposed. The proposed correlation was compared with the present experimental results and those in the literature. Reasonable agreement was obtained between the predicted and experimental values of circulation times. The downcomer liquid velocity was almost independent of the downcomer-to-rise cross-sectional area ratio. The correlation based on the concept of an eddy diffusivity predicted downcomer liquid velocities in Newtonian and non-Newtonian fluids.     

气流床气化炉内颗粒停留时间分布

颗粒停留时间分布是气流床气化炉开发与设计的重要参数,实验设计一种新型脉冲示踪法测量了气流床气化炉内颗粒停留时间分布。初步研究了多喷嘴气化炉和Texaco气化炉内颗粒停留时间分布,分析了气速和颗粒粒径对两种气化炉内颗粒停留时间分布的影响。结果表明：该实验方法具有良好的重复性和可靠性,可以用于气流床气化炉内颗粒停留时间的测量;与Texaco气化炉相比,颗粒在多喷嘴气化炉内的停留时间分布更为合理; 随气速的增大和颗粒粒径的减小,两种气流床气化炉内的颗粒停留时间和方差都增大。     

水泥浆体初凝时间预测的数值方法及其影响因素评价

提出了水泥浆体初凝时间预测的数值方法并定量评价了影响初凝时间的因素.通过引入周期性边界条件,描述了水泥颗粒初始分布和水化的计算机模拟技术.基于模拟的水泥浆体微观结构,给出了初凝时间算法并讨论了模拟次数对初凝时间的影响.通过与实验数据的比较,验证了该数值方法的有效性.定量评价了水灰比、水化温度、最小和最大水泥颗粒直径对初凝时间的影响.结果表明:水灰比和最大水泥颗粒直径是影响初凝时间的2个主要因素.     

两种改善毛细管电泳迁移时间重现性方法的比较

系统比较了迁移时间比法以及迁移时间与电压乘积倒数法对改善毛细管电泳迁移时间重现性效果的差异。选用双黄连口服液作为考察对象,通过对不同电压下实验结果的处理及平行实验结果的处理,发现内标峰位置的选择对两种方法的效果都有影响,以靠近电泳图中部的峰作为内标峰获得的结果较好,并且迁移时间比法优于迁移时间与电压乘积倒数法。用迁移时间比法对不同厂家或批次的双黄连口服液进行了分类比较,获得了较为满意的效果。     

SK静态混合器内各截面停留时间分布实验研究

采用脉冲示踪法对SK静态混合器内各截面的停留时间进行了实验测试,比较了流量对各截面停留时间分布的影响.结果表明:在同一截面上,随着流量增加,平均停留时间减小,停留时间分布密度曲线变得高而窄;在相同流量下,沿着轴线方向,平均停留时间增大,量纲一方差减小,流体流动趋向于活塞流.同一截面上,随着流量增加应答峰初期的斜率较陡,...     

一种计算搅拌槽混合时间的新方法

基于对混合时间定义的思考，提出了一种新的定义方法，在湍流流场数值计算的基础上通过求解示踪剂的浓度输运方程，研究了单层涡轮桨搅拌槽内的混合过程。结果表明：搅拌转速和搅拌桨安装位置都影响混合时间的大小，而进料位置对混合时间的影响不大。对于不同的搅拌转速而言，随搅拌转速的增大，相同体积分数对应的混合时间逐渐减小。当搅拌桨安装在槽中间位置时所对应的混合时间最小。利用适宜的尺寸和安装位置的导流筒可有效降低混合时间。