纳米ZnO对纳米ZrO2(8Y)致密特性及电导率影响研究

采用纳米ZrO2(8Y)粉和纳米ZnO粉为原料,对掺少量ZnO的ZrO2(8Y)进行无压烧结研究.实验结果表明,掺少量的ZnO能促进ZrO2与Y2O3的反应,加快四方相向立方相的转变,样品致密度和电导率显著提高.掺0.5wt％ZnO样品在1200℃煅烧2h的陶瓷致密度为94％,700℃时的电导率为9.02×10-3cm-1·Ω-1.     

低温共烧氧化铝/玻璃复合基板材料的研究

以低软化点的钙硼硅酸盐玻璃和氧化铝粉末为原料,制备了氧化铝/玻璃低温共烧复合基板材料。所需的玻璃粉体采用溶胶-凝胶法制备。研究了烧结温度和氧化铝含量对复合材料的烧结特性、介电性能以及力学性能的影响。结果表明,当氧化铝质量分数为50%,复合材料经950℃、保温2 h烧结后,其εr=5.92,tanδ=5.7×10-4,ρ=1012Ω.cm,抗弯强度σ=167.82 MPa,热膨胀系数α=4.86×10-6/℃,可望作为低温共烧多层陶瓷基板材料应用。     

低温合成ZnO-Li2O-B2O3-SiO2系陶瓷材料

采用微晶玻璃工艺,制备出一种ZnO-Li2O-B2O3-SiO2系陶瓷材料.该体系材料可在900℃空气气氛中烧结.烧结体的介电常数低于4,介电损耗为1.3×10-3.该烧结体中的晶相主要为圆球状和长柱状的Zn2SiO4,以及块状的SiO2.该材料适用于超高频多层片式电感领域.     

固相法制备低温烧结B2O3-P2O5-SiO2系低介陶瓷材料

采用传统的电子陶瓷生产工艺,制备出一种B2O3-P2O5-SiO2系瓷料.该体系材料加入少量助烧剂可在900℃,空气气氛中烧结,获得低介电常数陶瓷.得到烧结体的介电常数ε≤5、介电损耗tanδ≤3×10-3(1MHz),有望用于超高频叠层片式电感领域.     

Zn0.9Mg0.1O:Ga宽带隙导电膜的 PLD制备及性能研究

利用脉冲激光沉积法(PLD)制备了Ga掺杂的Zn0.9Mg0.1O(ZMOGa)宽带隙透明导电薄膜.采用各种分析手段研究了沉积温度和真空退火处理对薄膜结构、表面形貌及光电性能的影响.结果表明,制备的薄膜具有ZnO(002)择优取向;200℃下沉积的薄膜通过3×10-3Pa的真空400℃退火2h后,其电阻率由8.12×10-4Ω·cm减小到4.74×10-4Ω·cm,禁带宽度则由原来的3.83eV增加到3.90eV.退火处理增强了薄膜的择优取向和结晶度、增加了禁带宽度、提高了载流子浓度并使其透射谱线的光学吸收边发生蓝移现象.     

快中子辐照CZ-Si的FTIR分析

应用FTIR技术研究了不同剂量(1×1017～1.17×1019n/cm2)快中子辐照直拉硅(CZ-Si)的辐照缺陷和间隙氧在不同温度热处理时的行为.发现随辐照剂量的增加未退火的样品的间隙氧含量迅速下降,并且间隙氧的下降明显分为3个阶段.FTIR谱表明快中子辐照后主要的辐照缺陷为VO(829 cm-1)复合体.在低温条件下热处理300℃829cm-1(VO)开始消失并出现了825 cm-1(V2O2)、833cm-1(V3O2)、和840cm-1(V2O)和919cm-1(I2O2)四个红外吸收峰,退火温度升高到500℃后只剩下了825cm-1和919cm-1两个缺陷-杂质复合体的红外吸收峰.高温1100℃0.5h辐照引入的缺陷-杂质复合体很快的被消除.延长退火时间辐照样品和未辐照样品的间隙氧沉淀速度有很大的不同.     

掺镝的氟锆酸盐玻璃的光谱

测量了氟锆酸盐玻璃中Dy3+离子的吸收光谱和荧光光谱,得到了Dy3+离子的J-O参量Ωt,Ω2=3.29×10 20cm2,Ω4=1.56×10 20cm2,Ω6=2.48×10 20cm2.计算了氟锆酸盐玻璃中Dy3+离子的发射特性,Dy3+离子1.3μm发射的6F11/2(6H9/2)→6H15/2跃迁的发射截面σe=0.62×10-20cm2.研究了Dy3+离子浓度对其荧光强度的影响,当Dy3+离子掺杂浓度(摩尔分数)超过1.5%时,发生了浓度淬灭效应.     

掺铒碲酸盐玻璃光谱性质的J-O计算

研究了掺Er3+碲酸盐玻璃的吸收和荧光光谱性质;应用Judd-Ofelt理论计算了碲酸盐玻璃中Er3+离子的强度参数Ω(Ω2=4.79 × 10-20cm2,Ω4=1.52×10-20cm2,Ω6=0.66×10-20cm2),计算了离子的自发跃迁几率,荧光分支比;应用McCumber理论计算了Er3+的受激发射截面(σe=10.40 × 10-21cm2)、Er3+离子4I13/2→4I15/2发射谱的荧光半高宽(FWHM=65.5nm)及各能级的荧光寿命(4I13/2能级τrad=3.99ms);比较了不同基质玻璃中Er3+离子的光谱特性,结果表明掺铒碲酸盐玻璃更适合于掺Er3+光纤放大器实现宽带和高增益放大.     

两步镀膜Ti/Al/Ti/Au的n型GaN欧姆接触研究

报道了一种可靠稳定且低接触电阻的n型GaN欧姆接触。首先在掺硅的n型GaN(3×1018cm-3)蒸镀Ti(30nm)/Al(500nm),然后在氮气环境530℃合金化3min,最后蒸镀Ti(100nm)/Au(1000nm)用于保护Al层不被氧化。该接触电极有良好的欧姆接触特性,比接触电阻率为8.8×10-5Ωcm2,表面平坦、稳定、易焊线,可应用于制作高性能的GaN器件.     

溶胶-凝胶制备(Ca0.7Mg0.3)SiO3陶瓷及其微波介电性能

以硝酸钙、硝酸镁、正硅酸乙酯为先驱体, 利用溶胶-凝胶法合成了(Ca_0.7Mg_0.3)SiO₃陶瓷粉体, 研究了不同物相和粒径粉体的烧结特性以及陶瓷的微波介电性能. 结果表明: 干凝胶的煅烧温度低于800℃时, 所得粉体主要为无定型态, 煅烧温度超过900℃后, 晶相大量形成; 当以无定型粉体或900℃煅烧获得的细小粒径粉体为原料时, 均难以获得致密结构的陶瓷; 形成完整的粉体原料晶相以及粒径的增大, 有利于陶瓷体的致密烧结和微波介电性能的提高. 粒径分别为50～100nm以及90～300nm的陶瓷粉体, 在1320℃烧结后均获得良好的微波介电性能, 介电常数ε_r分别为6.62、6.71, 品质因数Q×f值分别为36962、41842GHz, 谐振频率温度系数τf分别为--48.32×10^-6/℃、--49.63×10^-6/℃.     

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.