染料敏化太阳电池有序介孔SiO2/离子液体凝胶电解质的研究

以P123为模板剂,采用溶胶-凝胶法制备有序介孔SiO2,用N2吸附、扫描电镜及透射电镜对样品进行分析.结果表明,制备的介孔SiO2呈短棒状,具有有序柱状孔结构,平均孔径为5.75nm.有序介孔SiO2固化二元离子液体(1-甲基-丙基咪唑碘/1-甲基-己基咪唑碘)形成凝胶电解质.由于凝胶电解质中离子液体在介孔SiO2的孔道中有序排列,使凝胶电解质I3-的扩散系数增大,从而降低了电解质的内阻,抑制了染料敏化纳晶多孔膜-凝胶电解质界面的复合反应,使凝胶电解质染料敏化太阳电池具有较大的开路电压和填充因子,光电转换效率达到5.22%.     

气-液界面二元共沉积法制备三维有序大孔SiO2

采用乳液聚合法制备粒径为229nm的单分散聚苯乙烯(PS)微球,以单分散PS微球和粒径为10nm的硅溶胶为原料,采用蒸发自组装法在气-液界面上二元共沉积,制备了大孔SiO2材料。结果表明,当SiO2体积分数为11%时,大孔SiO2材料呈现有序规整的FCC结构,其填充率为42%,收缩率仅为2%。低温N2吸附表明该材料在大孔孔壁上存在6.4nm左右的介孔,是一种具有大孔/介孔复合孔道结构的功能材料。     

纳米氧化物/Nafion复合膜的制备与性能表征

分别以SiO2、TiO2、Al2O3和ZnO等纳米氧化物为改性剂,采用流延法制得纳米氧化物/Nafion复合膜.XRD和ATR/FT-IR分析表明纳米氧化物在复合膜均匀分散,也没有发生团聚现象.对复合膜的质子传导和阻醇性能进行了测定,结果发现,纳米氧化物/Nafion复合膜具有较好的质子传导性能;阻醇性能均有较大幅度的提高,且以SiO2和TiO2改性的Nafion膜最为明显,甲醇透过系数分别从约10降低到约10-7和10-8数量级.这说明纳米氧化物/Nafion复合膜是一类较好的直接甲醇燃料电池用质子交换膜材料.     

二氧化硅基多孔块材的制备及其热稳定性

以非离子型表面活性剂P123和三甲基苯的微乳液为模板剂合成介孔SiO2粉体.以此粉体为原料,经干压成型、烧结制备多孔SiO2块材.分别用AlOOH溶胶和TiO2溶胶包覆多孔SiO2粉体,制成多孔SiO2/Al2O3块材和SiO2/TiO2块材.采用XRD、SEM、TEM、N2吸附法和阿基米德排水法对所制粉体和块材进行了表征,并研究了块材的热稳定性.结果表明,600～700℃烧结的多孔SiO2基块材的孔隙率为74%～76%.与多孔SiO2块材相比,在800～1000℃范围内,SiO2/Al2O3块材的热稳定性显著提高,SiO2/TiO2块材的热稳定性在800～900℃范围内有一定改善.     

低介电常数聚酰亚胺薄膜的制备与性能研究

用单体4,4′-二胺基二苯醚（ODA）和均苯四甲酸二酐（PMDA）添加纳米SiO2,在溶剂N,N-二甲基乙酰胺（DMAC）中,采用原位聚合法合成SiO2/聚酰亚胺（PI）复合薄膜。用氢氟酸刻蚀SiO2纳米粒子,引入纳米微孔,形成含有微孔的PI薄膜。造孔剂含量为15%时,薄膜的介电常数从纯聚酰亚胺的3.54降低至3.05（1kHz）。用透射电镜表征微孔结构,分析了微孔孔径和造孔剂（SiO2）含量对薄膜介电常数、耐热性、疏水性和机械强度等性质的影响。     

高温质子交换膜燃料电池用Nafion®/SiO2 复合膜研究进展

传统的质子交换膜燃料电池在高温下工作时,质子膜会因温度升高而发生脱水和膜电阻升高的现象,这对提高燃料电池的工作性能是一个致命的阻碍.由于Nafion(R)/SiO2复合膜具有较好的吸水和保水性能和较好的阻止甲醇渗透的能力,人们通过溶胶-凝胶法或重铸法合成了Nafion(R)/SiO2复合膜,并于高温(80～140℃)下应用在质子交换膜燃料电池和直接甲醇燃料电池中.简单介绍了Nafion(R)/SiO2复合膜的制备方法、结构性能及研究情况,并分析了存在的问题和其广阔的应用前景.     

双介孔SiO_2的原位合成及表征

以富含大孔或大介孔结构的硅胶为原料,在其上通过原位晶化合成具有小介孔-大介孔双孔分布的复合SiO2,并利用N2吸附-脱附、X射线衍射、扫描电镜、透射电子显微镜等手段对SiO2的物化性能和孔分布进行了表征。结果表明,所制备的样品具有双孔分布,孔径分别在3和45nm左右;小介孔的孔结构与MCM-41介孔类似,负载于硅胶表面及大孔孔壁上;大介孔的孔径较硅胶孔径有所减小,但未被完全填充堵塞。通过改变TEOS/大孔硅胶及CTAB/TEOS的配比可以实现对双介孔SiO2孔分布的调控。     

高温质子交换膜燃料电池用Nafion(R)/SiO2 复合膜研究进展

传统的质子交换膜燃料电池在高温下工作时,质子膜会因温度升高而发生脱水和膜电阻升高的现象,这对提高燃料电池的工作性能是一个致命的阻碍.由于Nafion(R)/SiO2复合膜具有较好的吸水和保水性能和较好的阻止甲醇渗透的能力,人们通过溶胶-凝胶法或重铸法合成了Nafion(R)/SiO2复合膜,并于高温(80～140℃)下应用在质子交换膜燃料电池和直接甲醇燃料电池中.简单介绍了Nafion(R)/SiO2复合膜的制备方法、结构性能及研究情况,并分析了存在的问题和其广阔的应用前景.     

双介孔SiO2的制备及表征

以正硅酸乙酯(TEOS)为硅源,十六烷基三甲基溴化铵(CTAB)为模板剂,采用溶胶-凝胶法制备了具有双介孔独立分布的SiO2,并用FT-IR、HRTEM、BET等方法对SiO2进行了表征.结果表明,双介孔SiO2中存在大量无序排列的2～3nm的小介孔和18nm左右的大介孔,具有高比表面积(716.4～968.6m2/g)和大孔(1.03～1.63mL/g):通过改变氨水及模板剂的用量可以实现对孔分布的调控.     

SiO2f/SiO2-BN复合材料的制备及其性能

以石英纤维预制件和硅溶胶为原料,采用溶胶-凝胶法制备了SiO2f/SiO2复合材料,在此基础上用尿素法制备了SiO2f/SiO2-BN复合材料,并对其力学性能和介电性能进行了测试.结果表明,随着工艺循环次数的不断增加,复合材料的密度随之提高,但增长速度逐渐减慢.三次循环后,SiO2f/SiO2-BN复合材料密度达1.8...     

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.