纳米SiO_2材料的制备及其发光性能研究

采用溶胶-凝胶法制备了纳米SiO2,样品在800℃下煅烧2h。X-射线衍射(XRD)及扫描电子显微镜(SEM)测试结果表明,该材料具有非晶态结构,颗粒尺寸为90~100nm。该样品在紫外灯照射下发出强烈的黄绿色可见光;对样品进行荧光光谱分析表明,该材料可以发射出较强的490nm的蓝绿光和弱的520nm的绿光。     

可见光响应型HCa2TaNb2O10/(Pb1-xZnxS)的微波法制备及其光催化性能研究

通过微波辅助法和传统制备方法分别合成了可见光响应的光催化剂HCa2TaNb2O10/(Pb1-x ZnxS)。采用扫描电子显微镜(SEM)、X射线衍射(XRD)、紫外-可见光漫反射光谱(UV-Vis DRS)等方法对样品进行了表征,考察了样品在300W氙灯下的光催化制氢活性。研究结果表明微波辅助法所制备的样品产氢量为384μmol/(g·h),高于传统方法制备的样品,而且微波辅助法制备复合催化剂大大简化了制备步骤,缩短了时间。     

Mn掺杂TiO_2负载竹质活性炭纤维的制备及可见光光催化性能研究

采用溶胶-凝胶法和浸渍法制备Mn掺杂TiO2负载竹质活性炭纤维(Mn/Ti-BACF)光催化复合材料,利用扫面电镜(SEM)、X射线衍射仪(XRD)、傅立叶变换红外光谱(FT-IR)、紫外-可见光分光光度计(UV-Vis)等考察了Mn掺杂量对Mn/Ti-BACF复合材料结构和可见光光催化性能的影响。结果发现,Mn掺杂改善了TiO2在竹质活性炭纤维表面的负载;Mn离子的掺杂并没有改变样品基材的碳网结构,也未出现新的Mn—O的特征吸收峰。随着Mn掺杂浓度的增加,Mn/Ti-BACF样品中TiO2粒径逐渐减小,可见光下的吸光度先增加后减少。当n(Mn)∶n(Ti)=1∶200时,样品在可见光下对亚甲基蓝的降解率达到了97.7%。     

PAN预氧纤维径向结构的光密度法研究

针对聚丙烯腈(PAN)预氧纤维径向结构的分布特点,利用PAN预氧化结构对可见光的吸收作用,以可见光在纤维横截面上的透过率(光密度)为衡量标准,建立一种可定量表征PAN预氧化纤维径向结构的方法,即光密度法。结果表明:当测试样品厚度为400nm、光强为800lx时,光密度法表征纤维预氧化结构的径向分布特征最为准确灵敏。与传统的皮芯结构表征方法相比,该方法不仅可表示不同预氧化条件下纤维在相同区域的预氧化程度,还可获得预氧化程度在径向的分布情况。将该方法应用于PAN纤维的预氧化工艺研究,结果显示此方法可精确表达出工艺与结构的相关性,表明光密度法作为一种PAN预氧化程度表征的新方法,可在PAN预氧化径向结构研究中发挥积极的作用。     

简易合成Bi/Bi2MoO6/TiO2复合纳米纤维及其增强的可见光催化性能

以电纺TiO₂ 纳米纤维为基质, 葡萄糖为还原剂, 采用简单一步溶剂热法制备了等离子体Bi/Bi₂MoO₆/TiO₂复合纳米纤维。利用X射线衍射、场发射扫描电镜、透射电子显微镜、X射线光电子能谱、紫外-可见漫反射光谱和光致发光谱等对样品进行表征。以RhB和4-CP为模拟有机污染物, 评价材料的光催化性能。结果表明: 部分Bi ³⁺被葡萄糖还原成金属Bi纳米粒子, 原位沉积在Bi₂MoO₆纳米片上, 同时构筑在TiO₂纳米纤维表面。金属Bi的等离子体共振效应, 有效提高了样品的光催化活性。可见光照50 min, 样品对RhB的降解率为95.8%, 五次循环后仍保持在92%以上; 可见光照180 min, 样品对4-CP的降解率达68.8%。证实该材料具有良好的可见光催化活性和稳定性。     

水解超声合成CdS/TiO_2及其光催化净化甲醛研究

为了提高二氧化钛在可见光下的光催化性能,通过水解超声法合成CdS/TiO_2复合粉末,并以甲醛溶液为污染物,在可见光照射条件下对其进行光催化净化,分别考察了CdS/TiO_2摩尔比、反应温度、反应时间和超声时间等影响因素。采用扫描电子显微镜(SEM)、X-射线衍射(XRD)、傅立叶红外光谱(FT-IR)对所得样品进行表征。结果表明:当CdS/TiO_2摩尔比为0.75,超声时间为30min,反应时间为90min,反应温度为70℃时,制备得到的样品由锐钛矿相TiO_2、立方晶相和六方晶相CdS组成,光催化活性最佳,在可见光下光催化净化甲醛180min后,降解率达到40.12%。     

Ag和介孔碳改性Bi_2WO_6光催化剂的合成及其可见光下的光催化性能

采用水热法合成了花球状的Bi2WO6和介孔碳CMK-3/Bi2WO6的光催化剂,然后通过光还原得到了Ag负载的Ag/Bi2WO6和Ag-CMK-3/Bi2WO6,制备出可见光下具有高活性的光催化剂。利用紫外-可见漫反射光谱(UV-Vis DRS)、X射线衍射(XRD)、透射电子显微镜(TEM)、高分辨透射电子显微镜(HR-TEM)和扫描电子显微镜(SEM)对制备的样品进行表征,评价样品在可见光照射下降解亚甲基蓝(MB)的光催化活性。并研究了CMK-3和Ag负载在Bi2WO6上都能提高其光催化活性的机制。结果表明:CMK-3或Ag负载在Bi2WO6上都能大幅提高Bi2WO6的光催化活性,Ag-CMK-3/Bi2WO6光催化剂的光催化性能优于Ag/Bi2WO6和CMK-3/Bi2WO6光催化剂。     

高活性氮掺杂介孔二氧化钛的合成及性能研究

采用水热法, 以聚乙二醇(PEG)为模板, N,N-二甲基甲酰胺为氮源, 制备了氮掺杂的介孔二氧化钛。并用X射线粉末衍射(XRD)、傅立叶红外光谱(FTIR)、BET、透射电子显微镜(TEM)、紫外一可见漫反射谱(DRS)和X射线光电子能谱(XPS)等技术手段对制备样品进行了表征。结果表明: 所合成的样品具有锐钛矿结构,直径约20 nm, 并且具有一定的可见光活性。以甲基橙(MO)为光降解模型, 样品在可见光区表现出了较好的催化活性, 这取决于烷氧基和氮掺杂的协同效应。     

石墨烯修饰氮掺杂TiO2纳米材料的制备及光催化性能

以TiN粉末煅烧制备的氮掺杂纳米TiO_2(N-TiO_2)和氧化石墨烯为原料,在水热条件下制备了石墨烯修饰的氮掺杂TiO_2纳米材料(GNT)。利用X射线衍射(XRD)、扫描电子显微镜(SEM)、高分辨透射电子显微镜(HR-TEM)及X射线光电子能谱(XPS)等测试手段对所制备的样品进行了表征。紫外-可见漫反射吸收谱表明石墨烯与氮掺杂的共修饰使得TiO_2的吸收带边发生红移,且其可见光吸收性能明显提高。可见光照射下降解亚甲基蓝溶液的实验结果表明石墨烯修饰的氮掺杂TiO_2的光催化降解性能分别是TiO_2、N-TiO_2的4.3倍和1.9倍。     

核壳结构CdS/ZnS@rGA的制备及光催化性能研究

为研究纳米CdS/ZnS@rGA复合材料在可见光下的光催化性能,采用一步溶剂热法合成了以ZnS为壳的CdS/ZnS核壳纳米粒子,将CdS/ZnS核壳纳米粒子附着在rGO纳米片上,并组装成CdS/ZnS@rGA复合气凝胶,用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)等对样品进行了表征,通过亚甲基蓝(MB)的光催化降解实验表明：CdS/ZnS@rGA复合气凝胶的形成不仅可以提高CdS的光稳定性,还可以增强对MB吸附能力,同时对MB的降解有明显的促进作用。可见光反应90 min, 50 mg的CdS/ZnS@rGA对100 mL 20 mg/L MB的去除率最高达到99%。经过5次循环实验,该材料仍具有较好的可重复利用性。     

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 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.     

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.     

Study on Bond Ability of Arc-Spraying Coatings with Different Surface Pretreatment on Cast-Iron

Arc spraying coatings are widely used in various applications, but uncommon in cast iron substrate. Different surface pretreatment technology is tested on substrates of gray cast iron. Surface roughness and residual stress were measured by TR200 and X-ray diffraction analyzer. Influence of different surface pretreatment methods ( dry blasting and fusebond) on roughness and residual stress was analyzed. The arc-sprayed coatings of wire 3Cr13 (φ2mm) on gray cast iron substrate is studied. The microstructure and interface of bonding layer were observed by SEM. The bond strength was taken by tensile test. Results show that bond strength with grit blasting is higher than fuse-bond; it is feasible to make wire 3Cr13 coating with arc spraying on cast iron substrate roughened by grit blasting.     

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.     

Evaluation of fatigue life of steel using steel grain size

The insightful discussion of the relationship between the construction of metallographic and fatigue life and proposition of mathematical relationships describing this relationship was conducted in the paper. This paper presents a method for estimating the fatigue life, based on the construction of the microstructural material taking into account the grain size and the participation of ferrite and pearlite phase.