纳米介孔分子筛的合成、表征与催化性能的研究

以硅酸钠为硅源、偏铝酸钠为铝源、十六烷基三甲基溴化铵为模板剂,两步水热法合成出了有序性好、热稳定性与水热稳定性高的介孔分子筛.XRD、AFM、TG、RT-IR、BET比表面和孔径测定以及热稳定性和水热稳定性研究表明:制得了粒径为30～50nm的纳米级介孔分子筛,并且所制备介孔分子筛的比表面积大于800m2/g;在1123K以上热稳定性好;100℃水热处理10天后有序性、孔径和比表面都没有明显的变化.负载Pt样品对苯加氢反应的催化性能研究表明,反应温度250℃、3.0MPa下,载Pt样品的苯加氢活性和选择性都接近100%,连续反应30h催化活性没有明显的降低.     

纳米介孔氧化铝的制备工艺及性能

分别采用碳黑和十六烷基三乙基溴化铵作为模板剂,硝酸铝为前驱体,用溶胶-凝胶法合成介孔氧化铝.通过N2吸附一脱附、TG-DSC等测试手段对样品进行了对比分析表征.考察了两种不同模板剂对其晶体结构、比表面及孔径大小的影响.实验结果表明,相对于十六烷基三甲基溴化铵或碳黑做模板剂,采用十六烷基三甲基溴化铵和碳黑组成的复合模板剂可以合成较大的比表面积、孔径和孔容(分别为370m2/g、6.5nm和1.54cm3/g)的介孔氧化铝,而且具有较窄的孔径分布.     

晶态骨架介孔CeO2和CeO2-ZrO2的合成与结构表征

以乙酸铈、乙酸锆为无机源,嵌段共聚物P123为模版剂,采用溶胶-凝胶法合成了介孔CeO2及CeO2-ZrO2复合体,用XRD、氮气吸附脱附、TEM、HRTEM、SAED等对材料进行了表征.结果表明,所得介孔CeO2具有规则的晶态孔道结构,孔径约在10nm左右,特别是其孔壁晶粒高度定向排列且平行于孔道方向.原位高温TEM观测表明,该介孔CeO2在800℃仍具有很高的孔道完整性.掺杂ZrO2后发现,在ZrO2摩尔含量低于30%时仍具备高度定向排列结构,高于30%时骨架晶粒取向逐渐趋向无序化.     

软模板法制备高比表面CeO_2-ZrO_2介孔结构材料及其表征

以非离子表面活性剂P123为模板剂,ZrOCl2.8H2O和Ce(NO3)3.6H2O为原料,制备出高比表面的CeO2-ZrO2复合氧化物介孔材料;研究制备CeO2-ZrO2介孔材料的主要影响因素,确定最佳合成参数;分析了CeO2-ZrO2介孔材料的形成和结构。     

囊泡状介孔SiO2合成因素的研究进展

讨论了利用不同类型的表面活性剂作模板,通过硅源的水解与凝聚反应得到不同孔径的囊泡状介孔SiO2的合成过程。综述了通过改变不同反应物(模板剂、硅源、助剂)及反应条件(温度、pH值)调控囊泡形成及介孔结构转变的相关机理,并对囊泡状介孔SiO2的应用和发展前景进行了展望。     

尿素-过氧化氢混合模板法合成介孔二氧化硅

以尿素-过氧化氢为混合模板、正硅酸乙酯为硅源,在酸性条件下,通过溶胶-凝胶过程合成二氧化硅介孔材料。采用煅烧法除去模板剂,用红外光谱、XRD、N2吸附-脱附、HRTEM等分析测试手段对介孔材料的结构和形态进行了表征。结果表明:与以尿素为单一模板相比,采用混合模板剂所合成介孔材料为蠕虫状,孔径分布基本保持不变、比表面积相近(分别为445、431m2/g)、孔径(分别为7.04、8.11nm)和孔体积(分别为0.783、0.874cm3/g)明显增大。     

工业硫酸氧钛合成有序介孔TiO2及其机理研究

采用复合表面活性剂CTAB和P123形成的超分子模板为结构导向剂,以工业硫酸氧钛液为钛源,控制溶液pH值及水解条件调控TiOSO₄的水解缩聚及与模板剂的自组装速率,钛水解胶粒通过界面作用形成介孔前驱体,脱模后制得二维六方,比表面积为205.7m²/g,平均孔径为3.28nm的锐钛型有序介孔TiO2. 用XRD、HRTEM、SAED及等温N2吸附等对样品进行了表征,初步探讨了介孔的形成过程. 钛水解胶粒和复合模板剂通过界面处的静电和氢键等相互作用,协同形成介孔结构,属协同作用机理.     

工业硫酸氧钛合成有序介孔TiO2及其机理研究

采用复合表面活性剂CTAB和P123形成的超分子模板为结构导向剂,以工业硫酸氧钛液为钛源,控制溶液pH值及水解条件调控TiOSO₄的水解缩聚及与模板剂的自组装速率,钛水解胶粒通过界面作用形成介孔前驱体,脱模后制得二维六方,比表面积为205.7m²/g,平均孔径为3.28nm的锐钛型有序介孔TiO2. 用XRD、HRTEM、SAED及等温N2吸附等对样品进行了表征,初步探讨了介孔的形成过程. 钛水解胶粒和复合模板剂通过界面处的静电和氢键等相互作用,协同形成介孔结构,属协同作用机理.     

溶胶-凝胶法室温合成介孔二氧化硅

以阳离子表面活性剂CTAB为模板,正硅酸四乙酯TEOS作硅源,在室温条件下制备介孔二氧化硅,用SEM、TEM、气体吸附等方法对产物进行表征,探究合成介孔二氧化硅的影响因素并解释合成机理。结果表明,较高的pH值以及较长的CTAB溶解时间明显改善了产物的孔径分布,EtOH的加入可提高体系的分散度,而单独控制TEOS水解效果甚微。Al 3+使得产物有序性下降,模板剂的去除方式影响试样外观和产率。说明合成过程是以CTAB形成的规则胶束为模板,TEOS嵌入至有序网络中,随后去除模板剂即得介孔结构。     

块状无裂纹介孔碳的合成和表征

以P123、F127作为模板剂,间苯二酚-甲醛为碳前驱体,利用水热合成技术制备了蠕虫状结构的块状无裂纹介孔碳。采用TG、FT-IR、TEM、N2吸附-脱附和元素分析等方法对介孔碳材料的结构进行了表征,分别研究了模板剂用量、模板剂种类对介孔碳结构的影响。结果表明:以F127和P123为模板剂制备的介孔碳均为蠕虫状结构。模板剂用量增加,介孔碳比表面积、孔径和孔容有所变大,但微孔的比表面积有所下降。模板剂种类不同,比表面积、微孔比表面积、孔容相差不大,但孔径相差较大。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

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.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

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.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Synthesis of Alumina-Zirconia Nanocomposites by Solgel Process

Al₂O₃-ZrO₂ nanocomposites were developed starting with the solgel process. Composite alumina-zirconia nanopowders were synthesized from metallorganic precursors (Aluminium secondary butoxide and zirconium Iso propoxide) using the solgel process. The parameters affecting the synthesis—solvent, concentration of precursor, R/H ratio (i.e., dilution of water in solvent)—were varied as also the temperature and pH. BET and TEM were used to measure nanosize. Diffuse reflectance spectroscopy and also qualitative optical absorption led to identical particle size estimate. The variation of process parameters was used to study the effect and interdependence of process parameters. Artificial Neural Networks was used to rigorously analyze the process. Although this led to confirmation of interdependence of parameters, the presence of a single overwhelming solvent variable was also established. Then the optimal process was used to synthesize more nanopowder. To produce bulk nanocomposite the nanopowders were sintered by varying the temperature and time period. The sintered lithoids were probed with a vickers hardness tester to measure elastic modulus, hardness, and fracture toughness. The results showed high elastic modulus, modest hardness, and very high fracture toughness.     

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.