PVA-PWA-Al2O3无机-有机复合质子交换膜的研究

以聚乙烯醇(PVA)、磷钨酸(PWA)和氧化铝(Al2O3)溶胶为原料,制备得到PVA-PWA-Al2O3无机-有机复合质子交换膜,测定了膜的电导率、含水率、溶胀度和甲醇透过系数等性质.测试结果表明,该复合膜具有较高的导电率和较好的阻醇效果,室温下测得电导率最高达到1.162 S/cm,甲醇透过系数在10-7cm2/s左右.复合膜中PWA含量增加,膜的电导率、含水率、溶胀度和甲醇透过系数都有所上升;膜中Al2O3含量增加,膜的电导率、含水率、溶胀度提高,但甲醇渗透系数稍有下降.     

聚乙烯醇/[Nbmd]OH碱性复合阴离子膜的制备及性能

以吗啡啉与溴代十二烷为原料,合成新型[Nbmd]OH碱性双核离子液体,并将[Nbmd]OH引入聚乙烯醇(PVA)的铸膜液中,通过浇铸法制备了掺杂碱性离子液体的复合阴离子膜PVA/[Nbmd]OH。采用热重分析及扫描电镜对所制备的复合阴离子膜的热稳定性及形貌进行表征。同时考察了离子液体含量对PVA/[Nbmd]OH复合膜的含水率、溶胀性能、力学性能及电导率的影响。结果表明,离子液体含量的增加可提高PVA/[Nbmd]OH复合膜的含水率、溶胀度、电导率等。其中,当碱性离子液体质量分数为20%时,复合膜的综合性能达到最优,此时,膜的含水率和拉伸强度分别达到161.6%和23 MPa,在70℃时,膜的电导率为2.11×10~(-3)S/cm,表明碱性离子液体的引入,能明显改善膜的导电性能,但是拉伸强度受到了一定的影响。     

磺化聚苯醚-磷酸锆质子交换复合膜的制备与性能研究

采用溶胶-凝胶法将磺化聚苯醚(SPPO)与磷酸锆(ZrP)复合得到质子交换膜,重点考察了ZrP含量对复合膜含水率、溶胀度和质子电导率的影响,采用红外光谱和交流阻抗法表征SPPO-ZrP复合膜的微观结构和质子电导率。结果表明,SPPO-ZrP复合膜含水率和溶胀度都随着ZrP质量分数增加而逐渐减小,当ZrP质量分数为20%时,膜的含水率和溶胀度分别达到18%和2.1%。通过交流阻抗法对质子传导性能的表征结果显示,随ZrP质量分数增加复合膜质子电导率逐渐增大,ZrP质量分数20%的SPPO-ZrP复合膜质子电导率在室温下达到1.6×10-2S/cm。     

磺化聚苯醚-磷酸锆质子交换复合膜的制备与性能研究

开发价格低廉且性能优异的质子交换膜是目前燃料电池研究的热点.采用溶胶-凝胶法将磺化聚苯醚(SPPO)与磷酸锆(ZrP)复合得到质子交换膜,重点考察了ZrP含量对复合膜含水率、溶胀度和质子电导率的影响,采用红外光谱和交流阻抗法表征SPPO-ZrP复合膜的微观结构和质子电导率.结果表明SPPO与ZrP产生相互作用使SPPO结构发生变化.SPPO-ZrP复合膜含水率和溶胀度都随着ZrP质量分数增加而逐渐减小,当ZrP质量分数为20％时,膜的含水率和溶胀度分别达到18％和2.1％.通过交流阻抗法对质子传导性能的表征结果显示,随ZrP质量分数增加复合膜质子电导率逐渐增大,ZrP质量分数20％的SPPO-ZrP复合膜质子电导率在室温下达到1.6×10-2S/cm.     

磺化杂萘联苯聚醚酮膜的制备及其阻醇和质子导电性能

采用浓硫酸和发烟硫酸的混合物作磺化剂得到不同磺化度的磺化杂萘联苯聚醚酮（SPPEK）,考察了不同磺化度的SPPEK膜的导电和阻醇特性．磺化度为73％的膜在测试的温度范围内膜的电导率数量级在10^-2S／cm,其甲醇透过系数约比Nafion 115膜低一个数量级,如果以质子传递通量和甲醇传递通量之比定义为综合指标,SPPEK膜的综合性能比Nafion 115膜高3．3倍。     

SPPEK/PWA质子导电复合膜的制备与性能

以磺化杂萘联苯聚醚酮(SPPEK)为基体,采用共混法制备了SPPEK/PWA复合质子交换膜。采用红外光谱、热分析与交流阻抗等方法对复合膜的结构和性能进行了研究,并与Nafion117膜进行了比较。结果表明,磷钨酸(PWA)的掺杂使得复合膜的吸水率和溶胀度增大,同时热稳定性能得到提高。复合膜在20℃时的质子电导率为0.67×10-2S/cm,接近Nafion117膜的质子电导率(1.08×10-2S/cm)。且随着温度的升高,电导率逐渐增大,最高可达1.18×10-2S/cm。此外,对复合膜不同方向上的电导率进行了测试,表明膜平面方向上的电导率(8.10×10-2S/cm)高于厚度方向上电导率(7.50×10-3S/cm)约一个数量级。     

聚乙烯醇/纳米零价铁复合膜的制备及性能

为了克服脱氧剂小袋包装与食品混装带来的工艺不足和安全问题,采用水热法制备了纳米零价铁（nZVI）,并将其与聚乙烯醇（PVA）进行溶液共混,制备了结构及阻氧性能更为优异的聚乙烯醇/纳米零价铁复合膜。利用傅里叶变换红外光谱（FTIR）、X射线衍射（XRD）、热重分析（TG）、差示扫描量热法（DSC）等对膜的结构和性能进行表征。结果表明：复合膜中PVA和nZVI实现了良好复合;加入nZVI后,复合膜的玻璃化温度（Tg）升高、热稳定性降低;随着nZVI含量的增加,复合膜的力学性能先增强后减弱,在nZVI质量分数为2%时,复合膜的抗拉强度和断后伸长率达到最大;复合膜的氧气透过系数随着nZVI含量的增加呈现先减小后增大的趋势,在nVZI质量分数为3%时,复合膜的氧气透过系数最小。在复合膜中,nZVI和PVA的羟基之间能形成一种强的相互作用,改善了复合材料的结构和性能,但nZVI及其表面部分氧化的变价铁催化加速了PVA的热降解。     

PAMPS/PVA复合质子交换膜的电导率及阻醇性能

制备了聚2-丙烯酰胺-2-甲基丙磺酸(PAM PS)/聚乙烯醇(PVA)复合质子交换膜,并研究了膜的组成、甲醇水溶液浓度等对膜力学强度、电导率和甲醇渗透率的影响。实验发现,当PAM PS含量为50%时,此复合膜拉伸强度可达21.8 M Pa,电导率σ可达1.5×1-0 2S/cm,并且甲醇透过率P仅为9.8×1-0 8cm2/S。     

叠合膜用于多组分体系渗透汽化脱水过程的研究

针对用渗透汽化—反应精馏耦合过程来实现溴丙烷的连续化生产时氢溴酸对PVA膜的腐蚀作用，用阻氢溴酸的PTFE基离子交换膜与PVA/PAN复合膜的叠合膜进行HBr—PrOH—H2O三组分体系的脱水．分别测试了PVA／PAN复合膜、PTFE基离子膜以及PTFE—PVA叠合膜对丙醇—水—氢溴酸的分离性能．渗透汽化结果表明，这种双膜叠合方法不但保持了PVA膜的高分离性能，而且有效地解决了氢溴酸对PVA膜的腐蚀问题．     

渗透汽化分离有机物

用不同的方法制备了几种分离有机物的膜，如CA/PAN、PVA/PAN的复合膜，以及含金属离子载体的PVA膜，这些膜是复合膜或非对称膜．测量了膜材料(CA和PVA—Me^n )的吸附特性并评价了其性能．结果表明，CA和CTA膜以及几种复合膜适于分离MTBE/MeOH，修正的溶解-扩散模型可成功地估算MTBE／MeOH透过CA膜的渗透汽化分离性能．从初步吸附试验看，含金属离子载体的PVA膜对分离苯／环乙烷体系可能是一好的候选膜．     

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.     

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.     

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.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.