氨硼烷水解制氢催化剂载体的研究进展

氢由于具有高效率和高功率密度而被认为是一种出色的清洁能源。化学储氢材料要求具有高的氢储存量。氨硼烷具有高氢含量(19.6%),且在普通贮存条件下稳定,被认为是有吸引力的储氢材料之一。由于氨硼烷在常温下不易放氢,故放氢催化剂成为氨硼烷放氢研究的核心技术和主要方向。金属催化剂可以显著提高水解放氢速度,是影响氨硼烷水解放氢的关键因素,但是金属颗粒催化剂一般都存在颗粒粒径生长过快、易团聚等缺点。为了解决这一问题,研究者选择不同的载体来分散催化剂,使催化剂金属分散在载体表面,防止团聚和过快增长,从而暴露更多活性位点,使催化氨硼烷放氢速率更快。文章将针对不同催化剂载体对氨硼烷水解的催化效果进行阐述。     

氮化硼先驱体的合成研究

收ＮＨ４Ｃｌ与ＢＣｌ３反应合成ＴＣＢ，然后与（Ｍｅ３Ｓｉ２）２ＮＨ和ＢＣｌ３在低温下反应获得具有硼氮六元环结构的ＢＮ陶瓷先驱体聚硼氮烷，并用ＩＲ，ＭＳ，ＤＴＡ，ＴＧ等对聚硼氮烷的结构及热稳定性进行了分析表征。结果表明，降低反应温度可提高聚硼氮烷的习率，决定产物溶解性能的主要因素是反应物料的配料比，反应所溶剂对聚硼氮烷的陶瓷产率影响最大。在１００℃下陶瓷产率可达３５－４５％。     

测定挥发性氢化物的新方法

挥发性氢化物是指硼烷、砷烷、磷烷、锑烷、硅烷和硒化氢等。     

化学气相沉积法制备高纯硼粉的技术进展

高纯硼是高技术和电子信息的重要材料,是军工和高科技不可缺少的一种重要的战略物资.本文阐述了氢和卤化硼、卤化硼及硼烷分别在金属基体表面、硼棒基体表面及采用流化床技术化学气相沉积制备高纯硼粉的几种不同制备方法,分析比较了各方法的优缺点,总结出以硼烷为原料,采用流化床技术可以制备产率高、纯度高的硼粉;探讨了副产物回收方法,并进一步提出将流化床和化学气相沉积技术相结合(FB-CVD),生产高纯硼粉具有高效、经济的特点,并可实现产业化.     

吡啶硼烷改性对沥青性能及组成的影响

以吡啶硼烷为添加剂对煤焦油沥青进行改性,考察了工艺条件（硼添加量,反应温度,反应时间）对改性沥青软化点、残炭值及其族组成的影响,发现吡啶硼烷参与并促进了沥青分子的反应,其结果是随着硼添加量的增加,改性沥青的软化点、残炭值提高,TS组份的含量降低,而PI组份的含量增加,在同一反应条件下,体系有无吡啶硼烷,所得结果有显著差别,吡啶硼烷改性系列的软化点、残炭值及PI组分的含量均明显高于纯沥青系列。     

一种碳硼烷改性有机硅树脂的制备及其耐热性能

碳硼烷改性有机硅树脂是一种耐热性能优异的高分子材料,具有广阔的应用前景。然而由于聚合单体碳硼烷改性硅氧烷的合成条件苛刻,严重影响碳硼烷改性有机硅树脂的制备和应用。本研究利用羟基与异氰酸酯基间的加成反应,在温和的条件下合成了一种新型结构的碳硼烷改性硅氧烷-碳硼烷改性氨酯桥接丙基三乙氧基硅烷(CBR-Si),在此基础上经水解缩聚反应合成了碳硼烷改性有机硅树脂(CBR-PSQ)。研究结果表明,在二月桂酸二丁基锡的催化作用下,摩尔比为1∶2的1,2-二羟甲基取代碳硼烷(CBR-OH)与异氰酸丙基三乙氧基硅烷(NCO-Si)在60℃下反应12h,可得到CBR-Si。所得有机硅树脂CBR-PSQ具有优异的热稳定性和热氧化稳定性,热分解温度高达500℃,在N₂和空气氛围中800℃的残炭率约为80%。该研究为耐高温碳硼烷改性有机硅树脂的合成和制备提供了一条新途径。     

先驱体法合成氮化硼研究进展

综述了无氧有机先驱体法合成氮化硼的研究进展 ,系统介绍了由硼烷、硼吖嗪、卤化硼合成氮化硼的工艺条件 ,及由这些化合物制备聚合物先驱体的合成途径及其陶瓷转化 ,概述了先驱体法待研究的问题 .     

金属氨硼烷及其衍生物高容量储氢材料研究进展

氨硼烷因其超高的储氢量和较好的动力学性能,成为了最具潜力的储氢材料之一。从合成方法、放氢特性、晶体结构和反应机制等方面,综述了金属氨硼烷及其衍生物的研究进展。     

碳硼烷-有机硅聚合物的合成表征及热性能

以1,7-碳硼烷C为原料,合成了Si原子与碳硼烷笼直接相连的碳硼烷硅醇A和Si原子与碳硼烷笼之间含1个亚甲基的碳硼烷硅醇B。再以A和B为单体,与六甲基硅二胺进行高温缩聚,制备了主链结构不同的聚合物P1和P2。采用红外光谱、核磁共振氢谱法对产物结构进行了表征,并用热失重、差示扫描量热法对聚合物热性能进行了研究。结果表明,以2种碳硼烷硅醇为单体均能成功制备碳硼烷-有机硅聚合物,碳硼烷基团的引入可有效提高聚合物热失重性能,P1在氮气和空气中700℃的残炭率分别为81%和98%,P2在氮气和空气中的残炭率分别为53%和70%,远高于普通的有机硅聚合物。经高温处理后,聚合物的红外谱图中仍有强的B-H吸收峰,表明碳硼烷基团仍有部分保持。     

热塑性碳硼烷聚羟基酯醚的合成及热稳定性能

以o-碳硼烷双酚二缩水甘油醚和丁二酸、4,4-二羧基二苯醚为原料,四苯基溴化磷为催化剂,设计合成了2种碳硼烷聚羟基酯醚(P1和P2)。通过红外光谱、核磁共振和凝胶渗透色谱表征了所得聚合物的结构,结果表明得到了预期结构的聚羟基酯醚。通过差示扫描量热分析和热重分析(TG)评价其热性能,研究了碳硼烷结构对玻璃化转变温度(T_g)、初始分解温度和残炭率的影响。结果表明,P1和P2的T_g分别为-20.6℃和12.8℃,比不含碳硼烷的聚羟基酯醚(P0)高,表明大体积刚性碳硼烷笼形结构的引入提高了聚羟基酯醚的玻璃化转变温度。TG分析结果显示,碳硼烷笼形结构能在高温下极大地提升聚羟基酯醚的耐烧蚀性能,空气氛围下P1和P2的残炭率高于氮气氛围。     

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.