二元金属类水滑石的合成及其作为前驱体对NOx的吸附性能研究

用共沉淀法合成了多种二元金属类水滑石化合物,对其进行了XRD、IR表征,并测试了焙烧产物对NOx的吸附性能.结果表明,合成的样品都具有典型的水滑石层状结构;二元金属类水滑石化合物MAl-HTlcs(M=Cu,Mg,Zn,Co,Ni)对NOx均具有良好的吸附性能,其中锌铝型类水滑石(摩尔比Zn/Al=3)对NOx的吸附速率及饱和吸附量最大,饱和吸附量为1851mg/g.     

氧化吸附法合成硝酸根型铜铁铝类水滑石

采用氧化吸附法制备了硝酸根型铜铁铝类水滑石,借助XRD、FTIR、SEM等分析手段研究了样品的结构、形貌及形成机理.结果表明:存在水蒸气的条件下,以碳酸根型铜铁铝类水滑石为前驱体经过500℃焙烧得到的铜铁铝复合氧化物可以氧化吸附NO2,生成Cu(NO3)2.上述样品在干燥器中放置9 d后转化成直径约为5μm的硝酸根型类水滑石.此外,铜铁铝复合氧化物吸附NO2、H2O和O2后也可直接转化成硝酸根型铜铁铝类水滑石,不存在中间相Cu(NO3)2.本文提出的氧化吸附法为制备类水滑石提供了一种新途径.     

改性钴镁铝类水滑石对乙烯-醋酸乙烯共聚物阻燃和力学性能的影响EI北大核心CSCD

采用共沉淀微波晶化法合成了不同量硬脂酸钠表面改性的钴镁铝类水滑石。X射线衍射测试指出合成的所有类水滑石晶体均有高的结晶度,d_(003)值证实了硬脂酸根和硝酸根离子没有插入到类水滑石的层间。红外光谱、扫描电镜和接触角测试均证实了随着改性剂用量的逐渐增加,类水滑石表面硬脂酸钠的负载量也逐渐增加。热分析表明改性剂的负载量对类水滑石的热降解温度有较大的影响。当类水滑石以总质量的20%的比例添加到乙烯-醋酸乙烯共聚物(EVA)中制成复合材料时,氧指数和力学测试指出钴离子的加入,使得钴镁铝类水滑石比镁铝类水滑石对复合材料氧指数和断裂伸长率均有明显的提高。硬脂酸钠以前驱体质量的2%进行改性的钴镁铝类水滑石/EVA复合材料的强度、韧性和阻燃性能表现最好。     

改性钴镁铝类水滑石对乙烯-醋酸乙烯共聚物阻燃和力学性能的影响

采用共沉淀微波晶化法合成了不同量硬脂酸钠表面改性的钴镁铝类水滑石。X射线衍射测试指出合成的所有类水滑石晶体均有高的结晶度,d_(003)值证实了硬脂酸根和硝酸根离子没有插入到类水滑石的层间。红外光谱、扫描电镜和接触角测试均证实了随着改性剂用量的逐渐增加,类水滑石表面硬脂酸钠的负载量也逐渐增加。热分析表明改性剂的负载量对类水滑石的热降解温度有较大的影响。当类水滑石以总质量的20%的比例添加到乙烯-醋酸乙烯共聚物(EVA)中制成复合材料时,氧指数和力学测试指出钴离子的加入,使得钴镁铝类水滑石比镁铝类水滑石对复合材料氧指数和断裂伸长率均有明显的提高。硬脂酸钠以前驱体质量的2%进行改性的钴镁铝类水滑石/EVA复合材料的强度、韧性和阻燃性能表现最好。     

高活性丙烯腈水合铜基催化剂的制备与表征

在丙烯腈水合制备丙烯酰胺的反应中,采用共沉淀方法制备催化剂,通过反应考察了催化剂的催化活性,并用XRD和TPR对水合用铜基催化剂做了物相表征.结果表明,采用碱单流加料,Cu/Al为40/60时,反应转化率最高可达90.9%,选择性最高可达99.1%.XRD和TPR测定表明,催化剂的催化活性与孔雀石和水滑石晶相的粒度、两者的比例密切相关.两者粒度小,比例恰当,催化剂活性高.     

La改性Cu-Mn-Al催化剂超临界甲醇中催化木质素液化性能研究

采用并流共沉淀法制备了一系列La改性Cu-Mn-Al类水滑石前体,对La的添加量进行了考察,利用XRD研究了类水滑石前体的物相变化。将类水滑石前体置于500℃、空气气氛下焙烧获得La改性Cu-Mn-Al复合氧化物催化剂,并用于超临界甲醇中木质素的催化液化。利用XRD、N2吸附/脱附、H2-TPR等方法研究了La不同添加量对催化剂物化性质、物相结构的影响。考察了在不同反应温度和反应时间下,催化剂对超临界甲醇中木质素液化性能的影响。结果表明:合成前体具有完好的类水滑石物相,并且La的添加能够对焙烧后催化剂的各组分起到很好的分散作用,能够有效提高催化剂活性和稳定性;但La同时具有抑制甲醇重整的效果,催化剂中La含量过多在较低温度下不利于提高木质素转化率。     

NiMgAl类水滑石制备条件研究

采用共沉淀法合成了不同摩尔投料比的NiMgAl类水滑石化合物.测定了Ni、Mg、Al单盐以及不同摩尔比的混合硝酸盐溶液的滴定曲线,考察了加料方式、晶化温度、晶化时间、原料配比对类水滑石合成的影响.通过XRD、IR对合成物进行表征,结果表明,在恒定pH值为8～9,n(Mg Ni)/n(Al)=1～3,n(Mg)/n(Ni)=8～16,晶化温度为65℃,晶化时间6h的条件下即得到晶相单=的NiMgAl-HTLcs;随n(Mg Ni)/n(Al)的增加,类水滑石结构的规整性提高,n(Mg)/n(Ni)比增加,层间距略有减小.     

纳米晶镁铝水滑石制备机理及抗毒性研究

以尿素为沉淀剂制备纳米晶镁铝水滑石,考察不同镁铝比制备的纳米晶镁铝水滑石催化剂对大豆油酯交换的影响以及催化剂的抗水抗酸性和使用寿命,并探讨纳米晶镁铝水滑石的合成机理.随镁铝摩尔比增加,酯交换反应所需时间减少,当m(Mg2 ):m(Al3 )=3:1时,转化率高达94.2%;当m(Mg2 ):m(Al3 )=4:1时,使用寿命最长,可重复使用5次.纳米晶镁铝水滑石具有较强抗水抗酸性,故在进行酯交换反应中无须脱水脱酸.     

Rose bengal-Cu-TiO2的制备及可见光制氢活性研究

用光还原方法制备了负载Cu的光催化剂Cu-TiO2,用染料Rose bengal敏化Cu-TiO2制备了具有可见光活性的Rose bengal-Cu-TiO2光催化剂,通过可见光(λ≥420nm)下分解水制氢考察了催化剂的活性,利用XRD、UV-vis吸收光谱对样品进行了表征.结果表明:载Cu增强了TiO2对可见光的吸收,Cu负载量对催化剂活性有一定的影响,Cu的最佳负载量为5%(质量分数).Cu的负载也增加了TiO2对染料的吸附,从而提高了TiO2对可见光的吸收和光催化活性.     

镁铝铜水滑石的合成、表征及性能研究

采用共沉淀法合成了不同摩尔投料(Mg/Al/Cu)的碳酸根型水滑石，用X-射线、红外光谱、热重．差热分析对水滑石进行了表征，测定对NOx的吸附性能。结果表明，Mg/Al/Cu摩尔比为2．5：1：0．5，2：1：1，1：1：2时合成的复合氧化物中都具有“feitknecht”结构。热重-差热分析结果显示合成样品的分解均有两个过程，掺入铜量少，热稳定性高。Mg/Al/Cu为2．5：1：0．5的水滑石对氮氧化物的吸附容量为1484．4mg/g。     

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...     

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.     

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.……     

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.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Friction Stir Processing Strategies for Uniform Distribution of Reinforcement in a Surface Composite

Friction stir processing (FSP) is an important technique for preparing surface composites. Fabricating defect-free surface composites with uniform particle distribution by FSP is a challenging task. In this study, silicon carbide particles reinforced AA5083 alloy surface composites was fabricated using different FSP strategies including variation in process parameters, dual-tool processing and tool offset overlapping. Material flow of the processed material with reinforcement particles demonstrated that the distribution of particles was influenced by the stirring action of the probe as well as the extrusion of the plasticized material due to the movement of the tool. Process parameters, particularly rotational speed, showed a dominant influence on the distribution of silicon carbide particles.