纳米结构苯胺/吡咯共聚物的静态法合成及自组装

采用静态聚合法,以过硫酸铵为氧化剂,使苯胺与吡咯进行共聚,制备了高产率(88%)的纳米结构苯胺/吡咯(PANPY)共聚物。研究结果发现,苯胺/吡咯摩尔比和聚合介质对共聚物的形貌有重大影响。以1.0 mol/L盐酸溶液为介质,苯胺/吡咯摩尔比为90/10时,可制得直径为70 nm～90 nm、长为1.3μm的共聚物纳米纤维;苯胺/吡咯摩尔比为50/50时,得到平均粒径约为400 nm的杨梅球状共聚物颗粒,透射电子显微镜的结果表明这些杨梅球状共聚物颗粒是由直径为5nm,长25nm的共聚物微小纳米纤维自组装而成。而以0.1 mol/L NaOH水溶液为反应介质,则可以得到外直径为1.8μm～2.6μm的自组装共聚物微球。     

导电性微纳米结构N-乙基苯胺/苯胺共聚物的静态合成

以N-乙基苯胺（NA）、苯胺（AN）为单体,过硫酸铵（APS）为引发剂,通过静态聚合法制备了导电性微纳米结构N-乙基苯胺-苯胺共聚物（PNAAN）。结果表明,共聚物的形貌、结构和性能强烈依赖于NA/AN物质的量比和APS/单体物质的量比。APS/单体物质的量比为1.0时,PNAAN（10∶90）共聚物为直径139 nm...     

聚苯胺/醋酸丁酸纤维素导电复合膜制备研究

以机械活化固相法制备的醋酸丁酸纤维素(CAB)为基底,充分溶解后与苯胺均匀混合,以过硫酸铵为氧化剂,盐酸为掺杂剂,采用原位聚合法制得聚苯胺(PANI)/CAB(PANI/CAB)导电复合膜。探讨苯胺加入量、过硫酸铵与苯胺摩尔配合比、盐酸浓度以及反应时间对导电复合膜导电性能的影响,研究结果表明:CAB用量0.5g,苯胺单体加入量1.25g,过硫酸铵与苯胺摩尔配合比为1∶1,盐酸浓度1.5mol/L,反应时间11h条件下,制得的PANI/CAB导电复合膜的导电性最好,电导率达到0.255S/cm。     

合成吡咯-苯胺共聚物亚微米颗粒及增强的超电容性

采用简单的化学氧化聚合直接合成吡咯-苯胺(Py-An)共聚物亚微米颗粒。所得共聚物的产率和电导率受聚合条件如共单体配比、聚合温度和氧单比的影响。当n(Py)/n(An)=7/3,氧单比为1,共聚温度为20℃时,共聚物具有相对较高的产率(57.5%)和电导率(2.61S/cm)。红外光谱(FT-IR)的分析结果表明,共聚物分子链由吡咯和苯胺链段构成,并随着共单体配比的不同而变化。扫描电镜(SEM)显示Py-An(7/3)共聚物呈现亚微米尺度的无规则颗粒状形貌,粒径约300~500nm。相对均聚物来说,Py-An(7/3)共聚物显示出更好的溶解性和赝电容特性。循环伏安(CV)的研究表明Py-An(7/3)共聚物的质量比电容为256F/g,且1 000次循环后仍能保持初始比电容的97.6%。     

微乳液法制备纳米TiO_2粉体的研究

以硫酸法钛白粉生产中间产物偏钛酸为原料,通过微乳法制备纳米TiO_2粉体,分析微乳法制备纳米粒子的反应过程及机理,研究反应物浓度、水与表面活性剂摩尔比以及表面活性剂用量对纳米颗粒粒径的影响。研究结果显示通过此微乳液体系,在偏钛酸溶液中钛盐摩尔浓度为2.0mol/L、水与表面活性剂摩尔比为50∶1、正己醇与曲拉通X-100的质量比为1∶0.3条件下,制备的TiO_2纳米粉体形状规则,平均粒径为25nm,具有分散度好、粒度分布均匀等特点。     

化学氧化合成N-乙基苯胺与苯胺共聚物的防腐性能

通过开路电位法详细研究了掺杂酸种类、掺杂状态和共聚单体摩尔比等对化学氧化合成的N-乙基苯胺与苯胺(EA/AN)共聚物的防腐性能的影响。结果表明,所有EA/AN共聚物的防腐性能均优于两种单体的均聚物,单体喂入摩尔比EA/AN为20/80的去掺杂态共聚物表现出最优防腐效果。盐酸掺杂共聚物的防腐性能优于其它酸掺杂共聚物的,去掺杂态共聚物又优于掺杂态共聚物。尤其是在强酸性腐蚀介质中,以该共聚物为底漆,环氧树脂为面漆的复合涂层钢板的开路电位在浸泡过程中出现了不降反升现象,涨幅达110 mV左右,较裸露钢板相应正移了约545 mV,较聚苯胺复合涂层涂覆的钢板相应正移了约90 mV,在长达半年的浸泡后,涂层不脱落、不起泡,也无锈点出现。     

水热法制备纳米银颗粒的试验研究

以AgNO_3和NaHCO_3为反应原料,以PVP为保护剂,用水热法制备出纳米银颗粒。研究了AgNO_3浓度和分散剂PEG的加入对反应生成纳米银颗粒形貌的影响。结果表明,在AgNO_3浓度为0.06 mol/L,NaHCO_3浓度为0.15 mol/L,PVP为0.03 mol/L,PEG为0.05 mol/L,反应温度为200℃,反应时间4 h的工艺条件下,可得到平均粒径尺寸约50 nm、分散性好、尺寸均一的近球形纳米银颗粒。     

界面聚合法合成柠檬酸掺杂聚苯胺微/纳米结构的研究

以苯胺为单体,过硫酸铵为氧化剂,采用界面聚合法制备了柠檬酸掺杂的微/纳米结构聚苯胺,利用SEM、FT-IR、UV-Vis、XRD及四探针法对其形貌、分子结构及电性能进行了表征。结果表明柠檬酸对聚苯胺进行了有效掺杂,掺杂酸浓度及氧化剂用量对纤维状结构聚苯胺的形成有影响。其中固定[CA]=0.1mol/L,[An]=0.1mol/L(CH2Cl2),过硫酸铵/苯胺摩尔比较小时[n(APS)∶n(An)=1∶4],能够得到形貌较规整的聚苯胺纳米纤维结构,且电导率较高。     

电致变色材料聚苯胺-邻胺基苯甲酸的合成条件及性能的研究

聚苯胺-邻胺基苯甲酸是一种溶解性能好的电致变色材料.探讨了单体摩尔分数、单体浓度、氧化剂用量、反应时间、反应温度及酸度对聚苯胺-邻胺基苯甲酸性能的影响.得出在苯胺与邻胺基苯甲酸摩尔分数为2∶1时,制得溶解性和电致变色性都很好且产率较高的聚苯胺-邻胺基苯甲酸的较佳反应条件为:盐酸浓度为1.2 mol/L左右,反应时间为4～6h,反应温度为20～25℃,单体浓度为0.4mol/L左右,氧化剂和单体摩尔浓度之比为1∶1.     

单分散γ-Al_2O_3纳米颗粒制备工艺参数的调控

采用均相沉淀法,在950℃煅烧碱式硫酸铝(Al(SO_4)_x(OH)_y)纳米颗粒2h,制备出单分散的γ-Al_2O_3纳米颗粒。研究了阴离子、浓度和沉淀剂/铝盐摩尔比对Al(SO_4)_x(OH)_y颗粒的形貌、尺寸和分散性的影响。结果表明,Al(SO_4)_x(OH)_y颗粒的最佳制备条件为:二甲胺硼烷(DMAB)作沉淀剂、Al_2(SO_4)_3.18H_2O作铝源、[Al~(3+)]=0.0005mol/L、n(DMAB)/n(Al_2(SO_4)_3·18H_2O)=40。制备出的Al(SO_4)_x(OH)_y具有球形、平均颗粒尺寸为98nm、粒径分布为75~130nm、单分散性的特点;获得了球形、平均颗粒尺寸为90nm、粒径分布范围为50~105nm、单分散的γ-Al_2O_3颗粒。     

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.