紫外光固化环氧丙烯酸酯/蒙脱土纳米复合材料的合成与表征

利用插层聚合合成了环氧丙烯酸酯／蒙脱土复合光固化树脂，并采用紫外光固化制备了环氧丙烯酸酯／蒙脱土纳米复合材料．用XRD、DSC对光固化过程中蒙脱土的插层和剥离行为进行了研究，并用FT-IR研究了蒙脱土对环氧-丙烯酸酯体系光固化速率的影响。力学试验证实，光固化后的环氧丙烯酸酯／蒙脱土纳米复合材料冲击与弯曲强度比原本体树脂分别提高了54％和10％．     

不饱和聚酯/蒙脱土阻燃纳米复合材料的制备及表征

采用原位插层复合法制备不饱和聚酯/蒙脱土阻燃纳米复合材料.通过XRD、SEM和TEM等手段表征不饱和聚酯/蒙脱土阻燃纳米复合材料的微观结构;通过拉伸、冲击和氧指数实验对不饱和聚酯/蒙脱土阻燃纳米复合材料的力学性能、阻燃性能进行研究.结果表明,当蒙脱土含量为0.5%时阻燃纳米复合材料与纯不饱和聚酯相比氧指数从22上升到24,此时拉伸强度提高8.76%,冲击强度提高68.65%.与阻燃剂/不饱和聚酯复合材料相比,同等阻燃级别下拉伸强度提高23.06%,冲击性能提高93.9%.     

阻燃剂/不饱和聚酯/蒙脱土纳米复合材料的性能

采用原位插层复合法,制备了包含十溴二苯醚和蒙脱土的阻燃剂/不饱和聚酯/蒙脱土纳米复合材料。通过XRD、SEM和TEM等手段表征阻燃剂/不饱和聚酯/蒙脱土纳米复合材料的微观结构。通过拉伸、冲击和氧指数实验对阻燃剂/不饱和聚酯/蒙脱土纳米复合材料的力学性能、阻燃性能进行研究。结果表明,当蒙脱土的含量为0.6%时,阻燃剂/不饱和聚酯/蒙脱土纳米复合材料的氧指数与阻燃剂/不饱和聚酯复合材料相比从24.1上升到25.4,冲击强度和拉伸强度分别提高82.66%和31.05%。燃烧残余物数码照片和扫描电镜照片显示蒙脱土促进了炭层形成。     

紫外光固化聚氨酯丙烯酸酯/蒙脱土纳米复合材料的制备与表征

采用原位聚合方法合成了可紫外光固化的插层型聚氨酯丙烯酸酯／蒙脱土复合材料,通过紫外光固化后制备了聚氨酯丙烯酸酯／蒙脱土纳米复合材料。利用FT-IR、XRD等对材料的结构、蒙脱土的插层和剥离行为进行了表征,采用TGA和应力-应变方法对复合材料的热学及力学性能进行了测试。结果表明,当蒙脱土含量为4％～5％时,聚氨酯丙烯酸酯／蒙脱土纳米复合材料的耐热性能有了明显提高,而拉伸强度和撕裂强度比纯聚氨酯丙烯酸酯分别提高了100％和50％。     

活性橡胶与蒙脱土复合增强不饱和聚酯/玻璃纤维复合材料的结构与性能

制备了丙烯酸酯封端聚氨酯(ATPU)和改性蒙脱土(OMMT)复合增强不饱和聚酯/玻璃纤维复合材料。通过扫描电子显微镜(SEM)等研究了ATPU和OMMT的复合对不饱和聚酯/玻璃纤维复合材料的力学性能、热变形温度和结构的影响。结果表明,丙烯酸酯封端聚氨酯与改性蒙脱土的复合具有协同效应,可以大大提高不饱和聚酯/玻璃纤维复合材料的冲击强度和拉伸强度,并使复合材料的弯曲强度、巴氏硬度和热变形温度略有提高;丙烯酸酯封端聚氨酯与改性蒙脱土的复合还提高了聚合物基体与玻璃纤维的界面粘合强度。     

酸酐固化环氧树脂-有机蒙脱土纳米复合材料的制备及性能研究

以甲基四氢酸酐为固化剂,对含羟基长链烷基季铵盐改性蒙脱土-环氧树脂纳米复合材料的制备进行了研究。通过TEM、SEM、TGA和DMA等对其微观结构、热性能和动态力学性能等进行表征和分析。TEM结果表明:有机蒙脱土以纳米片层分散在环氧树脂基体中,形成了纳米复合材料;有机蒙脱土含量3wt％时,环氧树脂被同时增韧增强:冲击强度提高87.8%,拉伸强度提高20.9%。纳米片层蒙脱土的加入同时也改善了环氧树脂的热稳定性和动态力学性能;有机蒙脱土含量5wt%时,热分解温度提高24.7℃,热变形温度提高了8.7℃;在T<T_g时,环氧树脂的储能模量提高42.86%,在T>T_g时,提高229.8%;相应玻璃化转变温度T_g提高14.7℃。      

熔融插层法制备PET/蒙脱土纳米复合材料及其性能的研究

采用熔融插层法制备PET/蒙脱土纳米复合材料.对制备的PET/蒙脱土纳米复合材料进行表征和研究,通过XRD分析了PET基体中蒙脱土片层的插层情况,发现达到预期效果;试验数据表明:有机蒙脱土使复合材料的拉伸强度和弯曲强度下降,拉伸模量和弯曲模量上升;随着有机蒙脱土含量的增加,复合材料的阻隔性能得到提高.     

PA6/MMT纳米复合材料的制备与表征

采用原位聚合法制备PA6/MMT纳米复合材料。利用超薄切片法制备原子力显微镜观测样品,实现了对复合材料中纳米蒙脱土分散情况的原位观测。对复合材料进行了扫描电镜、差示扫描量热、热重、X射线衍射、单轴拉伸、缺口冲击等实验,结果表明,超薄切片法制备的PA6/MMT纳米复合材料原子力实验样品较好地实现了对纳米蒙脱土分散情况的原位观测。插层过程扩大了蒙脱土片层的间距,蒙脱土在基体中分散均匀。蒙脱土在基体中起到了异相形核作用,复合材料的结晶速率升高,热分解温度有所下降。拉伸强度与弹性模量随蒙脱土含量的增加而增加。相比于纯尼PA6,复合材料的冲击强度有不同程度的增加。     

环氧/柔性分子插层蒙脱土复合体系的结构与性能

以柔性环氧树脂和丁腈橡胶的混合物为插层聚合物,有机化蒙脱土为多层无机片层结构,通过插层反应制备了一种类似宏观约束阻尼结构的微纳米级多层结构单元,进而与刚性环氧树脂共固化制得环氧/柔性分子插层蒙脱土复合体系,并对其结构与性能进行了分析表征。结果表明,X射线衍射和透射电镜表明,蒙脱土在环氧中保持了多层有序结构;力学性能测试表明,随着插层结构单元在环氧树脂基体中含量的增加,拉伸强度和弹性模量则趋于下降;通过动态力学测试表明,随着结构单元的加入,复合体系Tg的tanδ峰移向低温方向,峰型变宽。     

高强度高阻隔性再生纤维素/蒙脱土复合膜及其应用

通过共混方式制备了再生纤维素/蒙脱土复合膜,探究了不同含量的蒙脱土纳米片对再生纤维素膜强度与氧气阻隔性的影响。研究结果表明:蒙脱土纳米片占再生纤维素量的15%(wt,质量分数)条件下,制得的再生纤维素/蒙脱土复合膜的拉伸强度最大达到218MPa,断裂伸长率达到13.2%,透氧系数比纯再生纤维素膜降低了51.85%;将再生纤维素/蒙脱土复合溶液涂履纸上,能显著增强纸的力学性能和气体阻隔性能。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

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 Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

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.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

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.