焙烧温度对Cu-Mn/γ-Al_2O_3催化剂催化氧化甲苯性能的影响

采用浸渍法合成了Cu-Mn/γ-Al2O3催化剂,通过XRD、BET、H2-TPR和XPS等方法对经不同温度(300~600℃)焙烧的催化剂进行表征,采用固定床管式反应装置考察了焙烧温度对催化剂催化氧化甲苯的影响,并讨论活性组分、表面Cu+/(Cu++Cu2+)和Mn4+/(Mn4++Mn3+)摩尔比值与催化剂活性的关系。结果发现,550℃焙烧温度的催化剂活性最好,氧化能力最强,其转化率为95%时对应的反应温度T95(286℃)最低,CO2的选择性达100%。在550℃焙烧时生成的Cu1.4Mn1.6O4新相以及催化剂表面中相对含量更高的Cu+和Mn4+是催化剂具有高活性的主要原因。     

焙烧温度对CuO在γ-Al2O3载体上的分散和催化CO完全氧化性能的影响

采用浸渍法制备了经不同温度焙烧的CuO/γ-Al2O3催化剂,并通过BET、XRD、UV-DRS、H2-TPR以及CO完全氧化反应,研究了不同焙烧温度对CuO/γ-Al2O3催化剂中CuO组分的分散、还原和催化性质的影响.结果表明:当焙烧温度为450℃时,CuO在γ-Al2O3上的分散容量约为0.56mmol/100m2;当焙烧温度达到750℃时,Cu2 同时占据γ-Al2O3载体(110)面上的八面体和四面体空位.对于450℃焙烧的低CuO含量的样品,在H2-TPR结果中只观察到处于八面体空位的CuO物种的还原,而经750℃焙烧的样品则同时观察到处于八面体和四面体空位的CuO物种的还原,且处于八面体空位的CuO的还原会促进处于四面体空位的CuO的还原.处于八面体空位的CuO在CO完全氧化反应中的活性要高于处于四面体空位的CuO.     

液晶复合膜对H2,N2,CO及CO2气体分离性能的研究

本文研究了三种液晶/高分子复合膜对H_2、N_2、CO及CO_2等四种气体的透过情况。实验表明,液晶/高分子复合膜在液晶的熔点以下对H_2及CO_2具有较好的选择性,其原因可能是小分子液晶添加剂使聚合物的致密结构发生了变化。选择性αH_2/N_2、αH_2/CO等在液晶的熔点附近有较大的突跃。渗透系数P_(H_2),P_(CO_2)较之PVC膜均有数量级的提高。液晶分子结构对气体的分离系数有很大影响,液晶分子中是否含有酯基或氰基在液晶的熔点(T_(KN))以上的选择性αH_2/N_2、αH_2/CO、αCO_2╱N_2以及αCO_2/CO等可差别3～4倍。     

乙醇水蒸气重整制氢催化材料的制备及其性能研究

用浸渍法制备了以 CeO2 为助剂的镍基乙醇水蒸气重整制氢催化剂(Ni/CeO2/γ Al2O3)。该种催化剂在较低的温度下具有较高的氢气产率和较高的CO2 选择性,并使副产物 CH4 和 CO的选择性限制在较低水平。在 600℃,催化剂 16% Ni/CeO2/γ Al2O3的氢气产率可达4.8,生成 CO2、CO和 CH4 的选择性分别为70.7%、21%和7%。     

惰性气体超纯化过程中催化氧化痕量的一氧化碳和氢

在室温下工作的一台电子级气体纯化器最近由BOC集团技术中心研制成功。该纯化器可除掉几vppm的杂质,可使惰性气体中的CO、H_2、CO_2、H_2O和O_2等杂质含量降到<0.1vppm的水平。在研制过程中,为了选择最有效和最可靠的催化剂,考察了几种担载到载体上的金属催化剂在室温下氧化CO和H_2反应的催化行为。对于用担载Rh和Pt的催化剂,在低反应物浓度(<10vppm)和低温(20℃)下,其结果是过渡时间长,失活缓慢。如同在较高浓度和较高温度下氧化CO一样,观察到反应具有稳态的多重性,这被认为是反应机理的变化,此机理变化好象与失活过程本质有关。     

富氢气氛中CO选择性氧化CuO/CeO2催化剂的研究

选择负载型铜催化剂为研究对象,以富氢条件下研究CO选择性氧化反应为导向,考察了反应气氛、焙烧温度、CuO含量及Al2O3掺杂对CuO/CeO2催化剂的CO选择性氧化催化性能的影响,并采用TEM表征技术探讨结构与性能的关系。     

PdZn/ZrO2催化剂上二甲醚低温蒸汽重整制氢

采用溶胶-凝胶法制备ZrO2载体,然后采用沉积沉淀法制备一系列PdZn/ZrO2重整催化剂,对其进行BET、XRD的分析;并将其与水解催化剂(m(ZSM-5)∶m(γ-Al2O3)=2∶1)复合用于二甲醚蒸汽重整反应.考察了载体焙烧温度、表面活性剂、活性组分负载顺序和催化剂的装填方式对重整反应性能的影响.研究结果表明,以500℃焙烧,加入表面活性剂及PdZn共同负载制备的PdZn/ZrO2重整催化剂和水解催化剂机械混合组成的复合催化剂显示出较好的活性和较高的选择性,H2收率可达56.1％,CO2选择性为90.2％.     

纳米锐钛矿TiO_2及负载金催化剂的制备与催化性能

通过简单的水解-沉淀法制备了纳米TiO2,考察了反应条件对其粒径和晶型的影响。结果表明制备小粒径锐钛矿TiO2的有利条件为:倒加法;Ti(OBu)4与C2H5OH、H2O与C2H5OH和Ti(OBu)4与H2O的体积比分别为1/3、1/4和1/1;pH=7和400℃焙烧。沉积-沉淀法制备的Au/TiO2催化剂催化CO氧化结果表明,催化剂的活性受焙烧温度影响很大,200℃焙烧的催化剂具有最好的催化活性。     

用于CO2催化加氢In2O3基催化剂的研究进展

人类向大气中排放的大量二氧化碳(CO2)造成了一系列环境问题,极大地威胁了人类的生存.CO2催化加氢在众多CO2减排思路中具有独特优势.将CO2与氢气(H2)转化为高附加值的下游化学品,既可以减少大气中CO2浓度,又可以生产具有经济价值的商品,具有良好的应用前景.近年来,氧化铟(In2 O3)催化剂作为一种高效的新型CO2加氢制甲醇的催化剂在学界饱受关注.In2 O3表面经过活化后会产生大量氧空位,氧空位周期性产生和湮灭组成的机制抑制了副反应的发生,将CO2高选择性地加氢转化为甲醇.文献中报道In2 O3在200～300℃时甲醇选择性接近100％,特别是在高温下仍能维持高甲醇选择性.这种高温下优异的性能使In2 O3可被用于与沸石分子筛耦合制备催化CO2加氢直接制烃类化合物的双功能催化剂.In2 O3催化剂的缺陷在于其CO2的转化率较低限制了甲醇的产率.学界目前采取了一系列策略对In2 O3催化剂进行优化和改进.主要的策略有二:(1)将In2 O3负载在其他氧化物载体上;(2)在In2 O3体系中引入其他金属元素.将In2 O3负载在其他氧化物载体上可以增加In2 O3的分散度,增加催化剂中氧空位的含量,增强吸附CO2的能力,稳定关键的表面中间物种.将In2 O3负载在ZrO2上是该策略的典型例子,它可以极大地增强催化剂的本征活性.在In2 O3体系中引入其他金属元素可以增强H2解离吸附以及H2溢流的能力.文献中已经报道了在In2 O3体系中引入Pd、Pt、Cu、Rh、Au、Co、Ni等金属,并取得了良好的效果.本文归纳了In2 O3催化剂用于CO2加氢的研究进展,分别对In2 O3的结构、In2 O3用于CO2加氢的现状、以及新型In2 O3基催化剂的设计与改良三个方面对In2 O3在CO2加氢中的应用进行综述,并对In2 O3基催化剂用于CO2加氢反应的研究思路以及发展前景进行展望,以期为之后In2 O3催化体系用于CO2加氢的研究提供思路及参考.     

堇青石负载的Fe-Ni基催化剂对合成气合成C_2烃的影响

以堇青石为载体,采用浸渍法制备了一系列不同镍负载量的新型Fe-Ni基催化剂,并利用SEM、TEM、XRD、EDX、XPS手段对催化剂的结构和形貌等进行表征。研究发现,当镍的负载量为0.6%(质量分数)时,Fe-Ni基催化剂的分散性达到最好,导致催化合成C2烃效果最明显。此外,研究不同温度、空速、H2∶CO比例对合成C2烃的影响。结果表明,在450℃,H_2∶CO比例为2,反应空速为2 800mL/g cat-h情况下,一氧化碳转化率达到58.5%,C2烃的选择性达到37.7%,其中乙烯的选择性达26.6%,具有优异的催化合成效果。综上所述,0.6%(质量分数)镍负载量的Fe-Ni基催化剂对合成气合成乙烯以及C2烃,具有高催化效果,为工业生产乙烯以及C2烃提供新的参考与依据。     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.     

Early ironwork in Biscay: Survey,excavation, experimentation and materials characterization. An integral study of the mountainside ironworks (ferrerías de monte or “haizeolak”)

ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

Mechanism Study on the Wear of CrAlTiN Coated High-Speed Steel Twist Drills Under Dry Cutting Conditions

As demands about environment protection are growing up, dry cutting technology is getting more and more concerns from all over the world. Main works performed here are study on dry cutting performances and wear mechanisms of M2high-speed steel (HSS) twist drills with CrAlTiN multicomponent coatings, which was deposited using magnetron sputter ion plating system, in drilling 45 and 30CrMnSiA steel, and their comparisons to those in drilling the same steel but using monolayer CrN and commercial TiN coated drills. Drilling performances of drills are evaluated mainly through the measurements of width on outer corner flank land and the cutting forces. Results show that performances of CrAlTiN coated drills are better than those of monolayer CrN and TiN coated drills. In drilling 45 and 30CrMnSiA steel, the average tool life of the CrAlTiN coated drills are 17.2 and 11.8 times higher than those of the uncoated drills. Observing wear of the drill with scanning electronic microscope, results show that there is no crack or spallation of the CrAlTiN coatings in wear zones. Main mechanism of the wear here is adhesion.     

Structural Characteristics of TiO2 Ceramic Coating by Micro-Plasma Oxidation

TiO2 ceramic coatings with thickness of 20 μm were formed on the surface of pure titanium by micro-plasma oxidation. Their micro-structures were investigated by by using X-ray diffraction and their surface images were detected by using scan electronic microscope. There were three kinds of TiO2 coatings, pure anatase type TiO2 phase, mixed phases consisted of rutile type TiO2 phase and anatase type TiO2 phase, pure rutile type TiO2 phase. The coating surface with the pure anatase type TiO2 phase is rough, while the coating surface with the pure rutile type TiO2phase is smooth. The upper coating surface with the mixed type TiO2 phases is anatase type TiO2 structure and the subsurface of the TiO2 coating is rutile type TiO2structure.