Oxidation and Reduction Processes During NO x Removal with Corona-Induced Nonthermal Plasma

In this paper, the NO-to-NO ₂ conversion in various gaseous mixtures is experimentally investigated. Streamer coronas are produced with a dc-superimposed high-frequency ac power supply (10–60 kHz). According to NO _x removal experiments in N ₂ +NO _x and N ₂ +O ₂ +NO _x gaseous mixtures, it is supposed that the reverse reaction NO ₂ +ONO+O ₂ may not only limit NO ₂ production in N ₂ +NO _x mixtures, but also increase the energy cost for NO removal. Oxygen could significantly suppress reduction reactions and enhance oxidation processes. The reduction reactions, such as N+NON ₂ +O, induce negligible NO removal provided the O ₂ concentration is larger than 3.6%. With adding H ₂ O into the reactor, the produced NO ₂ per unit removed NO can be significantly reduced due to NO ₂ oxidation. NH ₃ injection could also significantly decrease the produced NO ₂ via NH and NH ₂ - related reduction reactions. Almost 100% of NO ₂ can be removed in gaseous mixtures of N ₂ +O ₂ +H ₂ O+NO ₂ with negligible NO production.     

聚砜-尼龙6嵌段共聚物结构的研究

<正> 以金属钠作催化剂合成的聚砜-尼龙6嵌段共聚物对尼龙6的吸水性有一定的改善,而且可以作为聚砜与尼龙共混物的相容剂,但共聚物中聚砜组分的含量都不超过25％。这可能与共聚物的结构有关。近年来的工作表明:反相气相色谱法(IGC)是高聚物结构分析的有用的工具之一。我们试图用反相气相色谱法,通过观察嵌段共聚物     

导电性聚呋喃的氧化合成及应用

总结了芳香族聚呋喃的氧化聚合方法,系统论述了聚合过程中影响聚呋喃性质的各种因素,推测了聚呋喃的链结构,介绍了聚呋喃的各种改进方法和效果。指出聚呋喃及其共聚物是一种电导率在10-11到10-1S.cm-1范围内有机半导体材料,其电聚合沉积膜具有奇特的电活性、优良的热加工性和特殊的表面形貌,可望在金属离子和有机物质的吸附与富集、传感探测等领域发挥作用。     

Conformations of fold part in isotactic polypropylene lamella with diamond lattice model

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含铈类水滑石的制备及其衍生物催化研究

采用共沉淀水热法制备了镍铝铈三元复合层状氢氧化物.详细探讨了合成体系pH值、Ce/Al比及陈化条件对合成产物物相的影响;通过XRD,ICP,TG-DTA手段研究了合成物物相、组成及热行为.考察了以合成物为前驱体经焙烧后转化为镍铝铈复合金属氧化物在催化消除NO反应中的应用.实验结果表明,合成镍铝铈三元复合层状氢氧化物的适宜条件是:M2 /M3 =2,Ce/Al=0.07～0.75,pH=5.5～6.9,水热处理条件为110℃,5 h;在pH=5.5～6.9条件下,合成原料配比不同,产物物相相同,但组成不同;合成物热稳定性较差,在T=100～400℃之间,层间吸附水及层间平衡阴离子NO3-脱去,转化为复合氧化物,将此氧化物应用于NO消除反应中,表现出高的低温活性,400℃进行反应,NO转化率达95%,N2选择性几乎100%.     

Pd-Rh型国Ⅲ排放三效催化剂的研制

对满足欧Ⅲ排放限值的Pd-Rh型三效催化剂进行研究开发,测试了新鲜催化剂的空燃比特性和起燃温度特性,并与市场上的欧Ⅲ催化剂在同等条件下老化后的性能进行了比较.对研制的催化剂进行封装总成后,按照GB18352.3-2005标准进行了常温冷起动Ⅰ型和低温冷起动IV型试验,测试结果完全能满足该标准的限值要求.     

A spectroscopic study on the 12-heteropolyacids of molybdenum and tungsten (H3PMo12−nWnO40) combined with cetylpyridinium bromide in the epoxidation of cyclopentene

The epoxidation of cyclopentene with hydrogen peroxide catalyzed by 12-heteropolyacids of molybdenum and tungsten (H₃PMo_12−nW_nO₄₀, n = 1–11), 12-tungstophosphoric acid and 12-molybdophosphoric acid combined with cetylpyridinium bromide as a phase transfer reagent was carried out in acetonitrile. Among 13 heteropolyacids investigated, catalyst of H₃PMo₆W₆O₄₀ showed the highest activity, giving a conversion of 60% and a selectivity of 95% in the epoxidation of cyclopentene. The fresh catalysts and the catalysts under reaction condition were characterized by UV–vis, FT-IR and ³¹P NMR spectroscopy, which has revealed that all of the molybdotungstophosphoric acids were degraded in the presence of hydrogen peroxide to form a considerable amount of phosphorus-containing species. The active species resulted from H₃PMo₆W₆O₄₀ are new kinds of phosphorus-containing species, which is different from {PO₄[WO(O₂)₂]₄}³⁻.     

La2O3-Mo5Si3/MoSi2复合材料的高温氧化行为

研究了0．8％La2O3-MosSi3／MoSi2复合材料在1200℃空气中的高温氧化行为。结果表明：0．8％稀土和MoSi3的加入，使材料的抗氧化性能降低。MosSi3含量越高，材料的抗氧化性能越差。当MosSi3含量低于30％时，在氧化初始阶段，质量变化呈直线下降，随着氧化的进行，氧化逐渐增重，材料表面形成较致密的SiO2阻止了材料的进一步氧化，使得氧化增重较小。而0．8％La2O3-40％Mo5Si3／MoSi2复合材料却出现了“粉化”现象。0．8％La2O3．MosSi3／MoSi2复合材料抗氧化性能的降低，归因于Mo5Si3差的抗氧化性和材料致密度的降低；另外，稀土和Mo5Si3的加入，细化了材料的晶粒，使晶界面积增加，加速了氧在晶界中的扩散，促进了材料的氧化。     

SA耐火材料多晶结构与性能的研究

本实验采用磨具废砂和炉皮SiC废砂生产SA耐火材料，通过XRD分析和计算机处理确定各试样中的晶相（4H－SiC，33R－SiC，3C－SiC，α－Al2O3，β-石英和Al6Si2O13）及其各相的含量。通过材料性能与结构综合分析，确定较好的配方，其含量：磨具废砂50％，炉皮砂45％，结合剂5％，外加矿化剂2％。     

在位分散聚合聚甲基丙烯酸甲酯/二氧化硅纳米复合材料研究

应用在位分散聚合方法制备了分散相粒径介于１３０ｎｍ左右的聚甲基丙烯酸甲酯／二氧化硅ＰＭＭＡ／ＳｉＯ２纳米复合材料，并利用ＳＥＭ，ＤＭＡ，ＴＧＡ等手段研究了该体系的性能．结果表明，经表面处理的ＳｉＯ２无机填料在复合材料基体中分散均匀，界面粘结好．ＳｉＯ２填充粒子的用量对基体的热稳定性，动态力学行为，光学行为以及拉伸强度，弹性模量，断裂伸长率等力学性能都有较大影响