纳米磁性流体的制备及性能分析

在磁流体制备过程中,利用x衍射仪(xRD)和透射电镜(TEM)对磁性纳米微粒的组成及粒径进行了分析,研究了磁性纳米微粒和表面活性剂对磁流体性能的影响.实验表明:Fe2 :Fe3 =1:2,反应温度为160℃,反应时间为6h,在适宜的时间加入6%的表面活性剂可以制备出性能较好的磁性流体.     

LPG埋地储罐泄漏渗流扩散多相混合数值模型及模拟（Ⅱ）数值模拟验证

采用本文（Ⅰ）报建立的LPG（liquefied petroleum gas）埋地储罐泄漏渗流扩散多相混合数值模型分别对气态和液态LPG在含水量不同的砂池中渗流扩散到外界环境的过程进行数值模拟,得到砂池中的流场、浓度场和LPG渗透到外界环境的质量流速。在数值模拟的基础上,对LPG气相、液相两种状态渗流扩散在砂池出口处LPG流速随时间的变化过程进行分析,总结出LPG渗透到外界的流速变化规律。模拟结果表明重力和出口位置对渗流扩散的方向影响很大,压力驱动是LPG渗流的重要影响因素;流体进出口处是流体流动活跃区域,非达西效应明显。数值模拟结果与LPG气体渗流扩散试验数据吻合较好,验证了理论模型和数值模拟的可靠性。     

Co-Phen-HAA/MMT催化分子氧氧化苯乙烯及其动力学研究

采用离子交换和配位合成方法,通过配位链将配体引入金属蒙脱土层间,制备了Co-Phen-HAA/MMT负载型催化材料,采用IR,XRD、SEM的现代分析测试技术,分析了催化材料的结构,XRD显示蒙脱土层间距增大0.577nm,表明配体进入金属蒙脱土的片层间;在分子氧的氧化作用下,考察了反应温度、时间、溶剂等因素对苯乙烯环氧化反应的影响.实验结果表明,最佳反应温度82℃,反应时间8 h,苯乙烯的转化率为93.9%,反应活化能41.35 kJ/mol.     

水中溶解氧量对除铁除锰效果的试验研究

地下水水质较好,不易污染,比较安全可靠.但是地下水中铁、锰含量过高给人们的生产生活带来很多的不便和危害.实验通过对溶解氧量的研究,发现溶解氧在一定范围内的变化对生物除铁除锰效率的提高无显著影响,原水溶解氧达到3 mg/L即可满足运行要求.     

PTFE-F-PbO2 电极在H2SO4溶液中的析氧行为

F-PbO2 electrode and polytetrafluoroethylene （PTFE） doped F-PbO2 electrode （PTFE-F-PbO2） were prepared on a plexiglas sheet substrate by a series of procedure including chemical and electrochemical depositions. The electrochemical activities of these two electrodes for oxygen evolution （OE） reaction were examined by electrochemical tests. In comparison with F-PbO2, PTFE-F-PbO2 electrode exhibited larger active surface area and higher oxygen vacancy deficiency, which resulted in its higher electrocatalytic activity for OE. In addition, both exchange current density and activation energy of the electrodes for OE were calculated in terms of active surface area. The values of exchange current density and activation energy in 0.5 mol·L^-1 H2SO4 aqueous solution were 1.125×10^ -3 mA·cm^-2 and 18.62 kJ·mol^-1 for PTFE-F-PbO2, and 8.384×10^-4 mA·cm^- 2 and 28.98 kJ·mol^-1 for F-PbO2, respectively. Because these values are calculated on the basis of the active surface areas of the electrodes, the enhanced activity of PTFE-F-PbO2 can be attributed to an increase in oxygen vacancy deficiency of PbO2 due to doping by PTFE. The influence of PTFE adulteration on the activity of PbO2 film electrode for OE was investigated in detail in this study.     

浅析相关参数对气流床粉煤加压气化的影响

介绍了气流床粉煤加压气化的原理及我国粉煤加压气化技术的研发过程、试车情况,分析了粉煤粒度、密相输送氮气量、氧煤比、蒸汽煤比、气化压力及气化炉温度等因素对粉煤加压气化的影响,为我国粉煤加压气化技术的产业化提供参考。     

HDPE/PA6/MRP共混物阻燃性能研究

用微胶囊化红磷(MRP)作为阻燃剂,利用双螺杆挤出机制备了阻燃HDPE/MRP共混物,并首次使用点燃氧指数和燃烧氧指数来表征它们的阻燃性能。结果表明:添加少量的PA6可提高HDPE/MRP复合材料的阻燃效果,固定PA6与MRP的添加总量为15%,且在HDPE∶PA6∶MRP=85∶4∶11时,其极限氧指数最大,为22.1%;在固定MRP含量的情况下,随PA6含量的增加,HDPE/PA6/MRP复合材料的阻燃性增强。     

温度补偿式氧化锆氧量分析仪的介绍

介绍温度补偿式氧化锆氧量分析仪的原理、结构及安装使用要求。在温度高于550℃时,该仪表与通用的氧化锆氧量分析仪性能完全一致,可精确测量沸腾炉炉气中的氧含量,并且解决了传统氧化锆氧量分析仪配套电加热炉故障问题,从而延长了氧化锆氧量分析仪的维修周期。     

Product and by-product formation in electrolysis of dilute chloride solutions

The results of an experimental study on electrochemical disinfection of water are presented. Attention was paid to the behaviour of chlorine compounds during electrolysis of water containing chlorides, with particular regard to the selectivity of the process towards the production of oxidising agents. Two reactor configurations were tested: a stirred tank cell and a filter press cell inserted in a hydraulic circuit. Both cells were equipped with boron doped diamond (BDD) anodes. Experiments were performed in batch and continuous mode. The effect of such operating parameters, current density, stirring rate or recirculating flow rate, on the behaviour of the process was investigated. The results at BDD anodes show that low current densities and perfect mixing of the system should be adopted in order to obtain high values of the concentration of oxidising agents avoiding the formation of such undesired by-products as chlorite, chlorate and perchlorate ions. Runs were also performed in which BDD was substituted by a commercial (Ti/RuO₂) DSA anode and the results obtained with the two materials are compared.     

Temperature programmed desorption of oxygen from Pd films interfaced with Y<Subscript>2</Subscript>O<Subscript>3</Subscript>-doped ZrO<Subscript>2</Subscript>

The origin of the effect of non-faradaic electrochemical modification of catalytic activity (NEMCA) or Electrochemical Promotion was investigated via temperature-programmed-desorption (TPD) of oxygen, from polycrystalline Pd films deposited on 8 mol%Y₂O₃–stabilized–ZrO₂ (YSZ), an O²⁻ conductor, under high-vacuum conditions and temperatures between 50 and 250 °C. Oxygen was adsorbed both via the gas phase and electrochemically, as O²⁻, via electrical current application between the Pd catalyst film and a Au counter electrode. Gaseous oxygen adsorption gives two adsorbed atomic oxygen species desorbing at about 300 °C (state β₁) and 340–500 °C (state β₂). The creation of the low temperature peak is favored at high exposure times (exposure >1 kL) and low adsorption temperatures (T_ads < 200 °C). The decrease of the open circuit potential (or catalyst work function) during the adsorption at high exposure times, indicates the formation of subsurface oxygen species which desorbs at higher temperatures (above 450 °C). The desorption peak of this subsurface oxygen is not clear due to the wide peaks of the TPD spectra. The TPD spectra after electrochemical O²⁻ pumping to the Pd catalyst film show two peaks (at 350 and 430 °C) corresponding to spillover O_ads and according to the reaction: