氮掺杂SrTiO3的制备及其可见光催化产氢活性研究

采用溶胶-凝胶法制备了钛酸锶,进而用固相法制备了氮掺杂SrTiO3,并用光沉积和氢气还原法制备了Pt负载的氮掺杂SrTiO3光催化剂.用XRD、SEM、UV-Vis漫反射和荧光光谱对其进行了表征和分析,考察了光催化剂在可见光下的产氢活性.研究了不同氮源、掺杂量、烧结温度和Pt负载量对催化剂产氢活性的影响.结果表明,三种不同氮源剂其掺杂效果为六次亚甲基四胺(HMT)>EDTA>尿素,而EDTA掺氮效果稍低于HMT.当氮源剂为HMT,SrTiO3与HMT质量比为1:3,焙烧温度为450℃时,所制备的光催化剂具有最佳的光催化产氢活性.在负载金属铂后,产氢活性有较大幅度的提高,其中用氢气还原法制备所得的光催化剂较光沉积法制备的具有更高的光催化活性,在最佳负载量均为2wt%时,两种光催化剂6h内的产氢量分别为6.89mmol和2.24mmol,分别是未负载铂样品产氢量的12倍和4倍多.     

PEG1000用量对多孔TiO_2薄膜结构及光催化性能的影响

以钛酸四丁酯为钛源,PEG1000为模板剂,乙酰丙酮为稳定剂,制备了TiO2溶胶,通过浸渍-提拉法在载玻片上制备了多孔TiO2薄膜。采用X射线衍射、扫描电镜、紫外-可见透射光谱、X射线光电子能谱、N2吸附-脱附等对TiO2薄膜的晶相结构、表面形貌、化学组成及TiO2粉体的BET比表面积和孔径分布进行了表征。考察了TiO2薄膜对甲基橙的光催化降解活性。实验结果表明,TiO2薄膜催化剂的晶型为锐钛矿型,Ti以Ti4+形式存在。随着PEG1000添加量的增加,薄膜表面形貌变得粗糙,孔数量先增加而后下降;多孔TiO2薄膜在紫外区域内的吸收边沿向短波方向移动,薄膜透射率也发生波动,但薄膜的厚度基本不变。当PEG1000添加量为2.0g时,薄膜中存在大量的介孔,薄膜的比表面积最大,光催化性能最佳。     

溶胶-凝胶法制备多孔纳米金属铜膜

为了制备多孔纳米金属膜材料,以醋酸铜为前躯体、聚乙二醇为模板剂、二乙醇胺为络合剂,通过溶胶-凝胶法在玻璃基片上制备了多孔纳米金属铜膜.利用XRD、IR、TG-DTG和SEM对所制备的纳米金属铜膜材料进行了分析及表征,并研究了溶胶浓度、PEG添加量、退火温度对多孔铜膜结构的影响.结果表明,当溶胶浓度为0.6 mol/L时,铜离子与PEG1000的毫克分子比值是42.86∶1,退火温度为500℃时,可以得到较好的多孔结构纳米Cu薄膜.不同的PEG加入量、溶胶浓度以及热处理温度都会对薄膜的形貌有较大的影响.     

冷冻抽提相分离法制备聚乳酸多孔支架

为了制备结构和性能满足骨组织工程支架要求的聚乳酸(PLA)多孔支架材料,采用冷冻抽提相分离法,以1,4-二氧六环和水为混合溶剂,聚乙二醇(PEG)为致孔剂,制得一系列PLA多孔支架,探讨了溶剂组成、PLA浓度、PEG添加量对PLA多孔支架结构和性能的影响,结果表明添加PEG有利于形成多孔三维支架,随着PEG含量的增加,...     

不同模板剂对氢氧化镧的微观结构及光催化性能的影响

以La(NO3)3·6H2O和KOH为原料,以EDTA、PVP和HMTA等为模板剂,采用微波水热法制备得到纯相La(OH)3,使用X射线衍射分析(XRD)、扫描电子显微镜(SEM)对产物的物相和形貌进行了分析,结果表明,不添加模板剂和添加EDTA、PVP、HMTA为模板剂时,可分别制备得到具有纳米棒状、类球形纳米颗粒、片状、纳米棒组装的片状形貌的纯相La(OH)3。光催化测试结果表明,模板剂可有效调控产物的微观形貌,并进一步提升La(OH)3的光催化性能。其中添加EDTA得到的类球形La(OH)3在21min内对亚甲基蓝的降解率可达99%。     

锶、氟双元素改性TiO2光催化材料性能研究

以多孔泡沫镍为载体,采用水热合成法制备了Sr改性和Sr、F共掺杂改性多孔光催化材料,采用XRD、TEM、SEM、FT-IR、UV-vis、XPS对样品进行了表征,并以样品对水中罗丹明B的降解性能为评价指标,对样品的光催化性能进行了评价.样品对水中罗丹明B的光催化降解反应为零级反应.Sr改性样品中生成SrTiO3晶体,TiO2以非晶态存在,光催化性能提高,最佳掺杂量为1.25%.煅烧处理后样品的光催化性能提高,最佳掺杂量为0.25%.0.25%Sr、2.0%F共掺杂改性样品中催化剂主体为锐钛矿型纳米TiO2,其光催化性能优于单一Sr改性样品,500℃煅烧处理使其光催化性能略有提高.     

多孔ZnO薄膜结构与光学性能研究

采用sol-gel提拉法,以聚乙二醇(PEG2000)为模板剂,醋酸锌为前驱体,乙醇为溶剂,二乙醇胺为络合剂,在玻璃基片上生长了多孔ZnO薄膜,利用SEM和紫外分光光度计分析了多孔ZnO薄膜的表面形貌和光学性质。研究了涂膜层数,模板剂加入量对多孔ZnO薄膜结构和透射率的影响。实验结果表明:随着涂膜层数的增加,薄膜的透射率有减小的趋势;当镀膜层数一定时,加入PEG2000后,有利于ZnO多孔结构的形成,在一定范围内,孔尺寸随PEG加入量的增加而增大,薄膜的紫外-可见光透射率随PEG加入量的增加而减小。     

钛酸锶光催化材料研究进展

近年来,钙钛矿型化合物以其特有的结构在光催化领域成为国内外研究的热点。钛酸锶(SrTiO3)是一种典型的钙钛矿型复合氧化物,具有稳定性高、无毒性,载流子迁移率高,光催化活性高等特点,作为半导体有低阻的电子运输结构和对小分子高效的氧化还原能力,是一种极具开发潜力和应用前景的光催化材料。主要介绍了SrTiO3材料的结构、制备方法与光催化机理,并对近年来SrTiO3在光催化领域的改性研究进行综述。最后在现有研究成果的基础上,对SrTiO3光催化材料的未来发展动向进行简要分析,有助于研究者取得进一步突破。     

超亲水多孔TiO_2薄膜的制备及其超亲水机理研究

以钛酸四丁酯为钛前体,聚乙二醇(PEG)为成孔剂,采用溶胶-凝胶法制备多孔TiO2薄膜。结果表明,该薄膜具有多孔表面特征,表面粗糙不平,在避光的条件下与水接触角小于5°。当煅烧温度为450℃以及煅烧时间为2h时,得到的样品超亲水性能为最佳。同时,还探讨了薄膜超亲水性能的形成机理,薄膜的超亲水特性是由光催化物质以及粗糙表面共同作用的,并且表观接触角是服从Cassie-Baxter模型。     

凝胶浇注结合固相烧结制备具有多级孔结构的碳化硅陶瓷

以Isobam作为胶凝剂, 聚甲基丙烯酸甲酯(PMMA)作为泡沫稳定剂和造孔剂, 结合固相烧结制备出具有多级孔结构的碳化硅陶瓷, 并研究了PMMA添加量、球磨机转速以及烧结温度对多孔陶瓷结构及性能的影响。结果表明: 当球磨机转速为220 r/min、烧结温度为2100℃时, 随着PMMA添加量由5wt%增加到20wt%, 发泡过程受到抑制, 但是泡沫的稳定性增强, 所得多孔陶瓷的气孔率在51.5%~72.8%之间, 压缩强度介于7.9~48.2 MPa之间; 当PMMA加入量为20wt%时, 随着球磨机转速由220 r/min增大到280 r/min, 加剧了浆料的发泡过程, 2100℃烧结所得多孔陶瓷的气孔率逐步增大, 气孔孔径变大; 当球磨机转速为220 r/min, PMMA加入量为20wt%时, 随着烧结温度的升高, 气孔率逐渐降低, 力学性能有所提高。     

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.