耐高温Al2O3/TiO2纳米复合粉体的制备及表征

以TiCl4、Al2(SO4)3为原料,采用液相沉淀法制备了Al2O3/TiO2纳米复合粉体,同时对该纳米复合粉体的相变过程和晶粒生长过程进行了详细的研究,对紫外-可见光吸收进行了检测.结果表明:纳米TiO2粉体经Al2O3复合后,其耐温性能得到极大提高,复合粉体经950℃煅烧后锐钛矿相含量仍然在77%,晶体粒径在20nm左右;锐钛矿向金红石晶型的转变温度在950～1100℃的高温区.复合粉体在低温煅烧后,紫外-可见吸收强度较纯纳米TiO2有较大提高,高温煅烧后,复合晶的紫外光吸收红移.     

液-固-溶液法制备ZnSe:Fe纳米晶及其光学性能研究

采用液-固-溶液(LSS)法制备了ZnSe:Fe纳米晶,利用X射线粉末衍射(XRD)技术、透射电子显微镜(TEM)、光致发光(PL)谱、紫外-可见吸收(UV-vis)光谱以及傅里叶变换红外(FT-IR)光谱对所制备样品的结构和光学性质进行了表征,研究了掺杂Fe离子对ZnSe纳米晶光学性质的影响规律.实验结果表明所制备的...     

超声辅助合成CeF3纳米晶及其表征

用超声波辅助法制备了CeF3纳米晶.并用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线粉末衍射(XRD)、紫外吸收(UV)光谱和荧光光谱(PL)对纳米晶的结构与性能进行了表征.结果表明:超声时间对所制备的CeF3纳米晶的形貌有很大的影响.随着超声时间的延长,所制备样品的形貌由"笼形"演变为规整的盘形.随着样品粒径的减小,纳米晶的紫外吸收峰和吸收带边发生明显的蓝移.纳米晶的荧光强度与纳米晶的结晶程度有关.     

超声辅助合成CeF3纳米晶及其表征

用超声波辅助法制备了CeF₃纳米晶.并用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线粉末衍射(XRD)、紫外吸收(UV)光谱和荧光光谱(PL)对纳米晶的结构与性能进行了表征.结果表明：超声时间对所制备的CeF₃纳米晶的形貌有很大的影响.随着超声时间的延长,所制备样品的形貌由“笼形”演变为规整的盘形.随着样品粒径的减小,纳米晶的紫外吸收峰和吸收带边发生明显的蓝移.纳米晶的荧光强度与纳米晶的结晶程度有关.     

纳米Cu_2Se的制备及其生长机理分析

采用一种新的合成技术,在复合氢氧化物熔融体中,以CuCl2·2H2和Se粉为原料在200℃下合成了Cu2Se纳米晶体,X射线衍射谱表明合成的Cu2Se纳米晶体属立方晶系结构,格点对称群为Fm3m(225),格点参数a=0.5765nm.扫描电子显微镜(SEM)和透射电子显微镜(TEM)图表明Cu2Se纳米晶体为厚度为10～20nm,宽度为200～300nm的片状结构.生长时加入少量的水会导致棒状非晶产生,水量越多棒状非晶的尺寸越大,使得Cu2Se晶体的均匀性和品质变差.根据配位多面体生长机理模型,计算了生长基元的稳定能,并探讨了在复合氢氧化物熔融中纳米Cu2Se晶体的形成机理.     

Zn_(1-x)Mn_xS稀磁半导体的合成与光学性能

通过水热法制备不同掺杂浓度的Zn_(1-x)Mn_xS(x=0.00,0.02,0.05,0.07)稀磁半导体材料,研究Mn~(2+)掺杂浓度对ZnS纳米棒微观结构和光学性能的影响。采用X射线衍射(XRD)、高分辨透射电子显微镜(HRTEM)、选区电子衍射(SAED)、X射线能量色散分析谱仪(XEDS)和紫外可见吸收光谱(UV-vis)对样品的晶体结构、形貌和光学性能进行表征。结果表明:制备的所有样品均具有结晶良好的纤锌矿结构,没有杂峰出现,生成纯相Zn_(1-x)Mn_xS纳米晶。样品形貌为纳米棒状结构,分散性良好。掺杂的Mn元素进入到ZnS纳米晶中,Mn~(2+)替代了Zn~(2+),而且随着Mn掺杂量的增加晶格常数减小。同时UV-vis光谱发现样品的光学带隙增大,发生了蓝移现象。     

复合结构纳米晶CdS：Cu/CdS的制备及光学特性

在非配位溶剂中合成了高质量的CdS纳米晶核,并利用Cu2+离子对其进行掺杂,制备了CdS:Cu纳米晶.通过进一步采用连续离子层吸附反应的方法对CdS:Cu纳米晶进行表面修饰,得到CdS:Cu/CdS复合结构纳米晶.利用X射线衍射(XRD),透射电镜(TEM),紫外可见吸收光谱(UV-Vis)和荧光光谱(PL)对其结构、形貌以及光学性质进行了表征和分析,结果表明:所制备的复合结构CdS:Cu/CdS纳米晶为立方闪锌矿结构;与CdS纳米晶核相比,掺杂Cu2+可以使其表面态发光发生红移;在CdS:Cu纳米晶中,通过改变掺杂Cu2+的浓度,可以实现表面态发光在570和620nm之间的连续调节.与未经包覆的CdS:Cu纳米晶相比,包覆层CdS增强了纳米晶CdS:Cu的稳定性.     

TiO2/全氟磺酸树脂纳米杂化薄膜的制备

采用溶胶-凝胶法制备了TiO2/全氟磺酸树脂(Perfluorosulfonated Resin,简称PSR)纳米杂化薄膜,并通过透射电镜(TEM)、X射线衍射(XRD)、红外光谱(FT-IR)、紫外可见光谱(UV-vis)及热重分析(TGA)等技术较为全面地测试了杂化薄膜的形貌、晶型、结构、光学及热力学性能.结果表明,TiO2/PSR纳米杂化薄膜表面平整光滑,基本没有裂纹;杂化薄膜在经水热处理后,两相在纳米尺度均匀分散,TiO2粒径约为8～10nm,呈锐钛矿型;同时杂化薄膜具有良好的光学透明性和紫外吸收性能,且随着TiO2含量的增加,全氟磺酸树脂紫外吸收性能有显著提高.     

碱金属化合物在水热法合成纳米ZrO2粉料中的作用研究

研究了各种碱金属化合物作为水热溶液在水热合成纳米ZrO2晶体中的作用以及过程动力学的特征.加入碱金属氟化物和KI对ZrO2的结构影响最大,它们能诱导快速形成单斜ZrO2晶体.揭示了碱金属氢氧化物和氟化物添加剂在纳米ZrO2晶体形成中的作用机理.     

硫化铋纳米花的可控制备

通过水热法以Bi(NO_3)_3·5H_2O为铋源、CH_4N_2S为硫源、尿素为矿化剂,在丙三醇与水的混合溶剂中制备不同尺寸的Bi_2S_3纳米花。运用X射线粉末衍射(XRD)、扫描电子显微镜(SEM)、高分辨透射电子显微镜(HRTEM)、紫外-可见-近红外分光光度计(UV-Vis-NIR)、荧光分光光度计(PL)等检测手段对样品进行表征。结果表明,合成的Bi_2S_3为正交相纳米晶结构,Bi2S3纳米花的生长是固相-液相-固相转化过程,样品形貌和尺寸受到反应物摩尔比、溶剂种类、合成温度、合成时间等因素影响。通过控制不同的条件可得到形貌均一的纳米花,并对Bi_2S_3纳米花的光学性能及生长过程进行了初步讨论。     

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.