齿科材料用酸酐类功能单体研究进展

齿科材料用酸酐类功能单体是目前应用最广泛、效果优良的一类齿科材料用功能单体。本文介绍了目前对酸酐类功能单体的结构、合成方法及在不同黏结环境下对黏结强度的提高效果的研究成果，讨论了酸酐类功能单体结构与单体本身性能和树脂黏结性能及其它性能关系，并着重探讨了对功能单体隔离基团结构、黏结性基团与可聚合基团位置及数量与黏结强度提高关系研究的重要性，最后对酸酐类功能单体的研究方向作了筒要的阐述．     

CO2共聚单体及产物改性的研究进展

CO2共聚物的研究开发在环境保护、资源再利用及新材料研究领域中都具有重要的意义。CO2共聚单体是影响其共聚产物结构、性能及成本的重要因素。文中综述了与CO2催化共聚的各类单体的研究进展及产物理化性能的特点,这些单体主要包括环氧化合物、烯类化合物和可再生型环氧烷烃;并介绍了通过三元共聚以调控分子链单元与分子链结构,从而改善聚合产物的理化性能。进一步就今后CO2催化共聚的发展方向进行了探讨。     

新一代高性能POSS-聚合物材料

描述了多面体聚硅倍半氧烷（Polyhedral Oligomeric Silsesquioxane,POSS)单体的结构与性能,POSS单体改性聚合物在塑料工业,航空与空间等领域的应用现状与前景,并对POSS单体合成技术,成本,POSS单体一步形成串凳式,悬笼式和笼－笼连接式结构作了综合评述。     

含苯乙炔基共轭单体的合成及荧光性能

通过苯乙炔基锂和氯硅烷的偶合反应合成了系列含苯乙炔基共轭单体(PES)。通过红外光谱(FT-IR)、核磁共振(1H-NMR、13C-NMR、29Si-NMR)、质谱分析(MS)和元素分析(EA)对其结构进行了表征,利用紫外光可见分光光谱(UV-Vis)和光致发光光谱(PL)研究了共轭单体的荧光性能,讨论了不同共轭结构与单体性能之间的依赖关系。结果表明,合成得到的共轭单体易溶于常见的有机溶剂(四氢呋喃、氯仿、丙酮、甲苯等)。而且随着单体结构中共轭程度的增大,紫外吸收光谱的最大吸收峰和荧光光谱的发射峰均发生不同程度的红移。其中,四苯乙炔基硅烷(TPES)由于结构极具对称性且共轭程度最高,发射峰红移至368 nm和738 nm处,在可见光范围内发射红光。     

高吸油性树脂的合成与性能

以甲基丙烯酸酯为单体，双烯化合物为交联剂，采用悬浮聚合方法合成高吸油性树脂。研究了单体结构、引发剂用量、交联剂用量及共聚单体配比对树脂性能的影响，并考察了高吸油性树脂对水面浮油的回收性能。     

有机氟改性丙烯酸树脂的合成及研究

使用不同的有机氟单体对丙烯酸树脂进行改性,合成了具有低表面能性质的有机氟改性丙烯酸树脂;对树脂进行了红外和分子量检测,并测试了涂膜的附着力、抗冲击力、接触角等各项性能;研究了不同的氟单体种类、氟单体用量以及合成工艺对树脂性能的影响。结果表明,氟单体对丙烯酸树脂进行低表面能改性效果明显,其中含有叔碳原子和甲基结构,分子中含有12个F的G04单体效果最为理想;采用滴加氟单体工艺能够显著增大树脂的接触角;当氟单体G04用量在16.7%时,树脂与水的接触角最大可达104.5°。     

基于咔唑的共轭聚合物材料的合成及性能研究

由咔唑以及3-噻吩甲酸出发,经过合理的化学修饰,合成了单体4,7-二溴正辛基咔唑M1和单体1,5-二(正三正丁基锡)-4,8-二(正十二烷氧基)苯并[1,2-b∶4,5-b’]二噻吩M2,然后单体M1与单体M2通过Suzuki偶联聚合合成了共轭聚合物P1。并对聚合物P1进行了一系列的结构表征和性能测试,结果表明P1的光学能带隙为1.56eV,电化学能带隙为1.57eV,5%热失重温度分别为314℃,显示出了良好的光学性能、热稳定性和电化学氧化还原性能。     

聚N-亚芳基苯并咪唑醚砜的无规共聚与性能表征

选用砜基双苯并咪唑作为第三单体,与砜基二酚以及砜基二氟单体进行亲核取代共聚,将苯并咪唑结构引入聚醚砜主链中,合成了无规共聚聚N-亚芳基苯并咪唑醚砜。对聚合物的涂覆成膜条件进行了探索,并对其表面性能、光学性能、热学性能、溶解性能和力学性能进行了表征。实验结果表明,当砜基二酚单体用量高于砜基双苯并咪唑单体用量时,所得聚合物可以通过涂覆法得到平整而透明的薄膜;双苯并咪唑单体的引入使得聚合物的耐热性有较大提高(玻璃化转变温度和初始分解温度分别升高56℃和44℃),但同时也使得聚合物的在有机溶剂中的溶解性能有所下降;聚合物薄膜具有较好的表面平整性和透光性,双苯并咪唑结构的存在有利于提高薄膜的平整性,但也使得薄膜的透光性有所下降;聚合物薄膜呈现脆性状态,且脆性程度随着双苯并咪唑单体用量的增大而增大,其断裂伸长率为3.1%~7.2%。     

BOPET薄膜涂覆改性用水性丙烯酸树脂的合成

以甲基丙烯酸甲酯(MMA)、丙烯酸乙酯(EA)为主单体,丙烯酸(AA)为功能性单体,通过溶液聚合方法合成了水性丙烯酸树脂。研究了丙烯酸含量、单体配比、加料方式、反应温度等条件对树脂性能和涂膜性能的影响,确定了最佳合成工艺。采用红外光谱(IR)、热失重分析(TGA)等测试手段对树脂的结构和性能进行了表征。     

苯胺及吡咯的共聚合研究进展

综述了苯胺及吡咯的共聚合机理、共聚物结构和共聚研究现状。着重讨论了取代基对聚合过程和聚合物性能的影响，以及在与其它共轭单体和非共轭单体共聚时的工艺方法．     

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.