磺化酚酞型聚醚砜/改性蒙脱土纳米复合膜的研究

用季胺盐改性蒙脱土和磺化酚酞型聚醚砜首次制得了磺化酚酞型聚醚砜/改性蒙脱土纳米复合质子交换膜,并用1H NMR、SEM、FT-IR等分析手段对其进行了表征,测定了复合膜的质子导电率.研究结果表明:改性蒙脱土以纳米颗粒形式分散于磺化酚酞型聚醚砜聚合物基体中;在相同测试温度下,磺化酚酞型聚醚砜/改性蒙脱土纳米复合质子交换膜的质子电导率随着改性蒙脱土含量增加而增加,添加10%(wt)改性蒙脱土的复合质子交换膜,在80℃下的质子电导率为8.53×10-4S/cm.     

磺化酚酞型聚醚砜/蒙脱土质子导电复合膜的表征与性能

采用浓硫酸为磺化剂,制备了磺化度为70.26%的磺化酚酞型聚醚砜,并通过添加有机蒙脱土制备了复合质子交换膜.研究了不同含量有机蒙脱土的复合质子交换膜的外观形貌,含水量,热稳定性和质子电导率,发现有机蒙脱土已经很好地分散在聚合物溶液中,复合膜的质子电导率在多种条件下均随着OMMT的添加量的增加而增加,其中SPES-C/OMMT10在80℃下经质子化处理后质子电导率达到8.53×10-4S/cm.     

燃料电池用磺化聚芳醚酮质子交换膜改性的研究进展

概述了近几年来燃料电池用磺化聚芳醚酮质子交换膜改性的研究进展,分别从共混法和有机/无机杂化法等两个方面总结了磺化聚芳醚酮质子交换膜改性的研究结果,并展望了今后的研究趋势。     

磺化聚芳醚酮砜/PVA复合质子交换膜的制备与性能

为了进一步提高质子交换膜在中高温时的质子导电率,文中以高磺化度的磺化聚芳醚酮砜(SPAEKS)和聚乙烯醇(PVA)为原料,通过溶液共混法制备了PVA不同含量的磺化聚芳醚酮砜/PVA复合膜。通过对复合膜的性能测试发现,PVA的引入提高了膜的热稳定性、吸水率和保水能力。而且SPAEKS/PVA复合膜的质子传导率高于SPAEKS膜,在80℃时,复合膜的质子传导率都在0.07 S/cm以上,能够满足中高温质子交换膜燃料电池的使用要求。     

磺化聚醚醚酮/蒙脱土复合型质子交换膜制备与性能

以磺化聚醚醚酮(SPEEK)为基体,以有机改性的蒙脱土(OMMT)为无机相,采用溶液插层法成功制备出了可望应用于直接甲醇燃料电池的SPEEK/OMMT复合型质子交换膜.通过X射线衍射(XRD)表征了复合膜的微观结构,并采用交流阻抗和隔膜扩散方法分别考察了复合膜的质子传导性能和阻醇性能.结果表明,蒙脱土的片层间距超过4.4 nm,SPEEK高分子链已插层到蒙脱土片层之间.与纯SPEEK膜相比,SPEEK/OMMT复合膜的质子传导率有所降低,但在90℃也达到了1.2×10-2S/cm的水平,而且蒙脱土的加入明显地降低了SPEEK膜的甲醇渗透率.     

燃料电池用磺化聚醚醚酮质子交换膜的研究

通过浓硫酸磺化法制备了具有不同磺化程度的磺化聚醚醚酮(SPEEK),并对此种质子交换膜进行了物化性能和H2／O2质子交换膜燃料电池性能研究,实验结果表明,SPEEK膜具有较理想的力学稳定性和气体渗透率,它的微观结构和质子传导性能与Nafion膜有所不同,经过其H2／O2质子交换膜燃料电池的性能研究,SPEEK膜能够保证电池在200h内稳定运行,有希望成为PEMFC用质子交换膜材料。     

燃料电池用碳氢聚合物质子交换膜材料研究进展

以我们在磺化聚酰亚胺和磺化聚硫醚砜方面的研究工作为基础,简要介绍了近年来燃料电池用碳氢聚合物质子交换膜的研究进展,包括各种材料的制备和性能(质子导电率、耐水性、尺寸稳定性、吸水率、甲醇透过率等)研究.此外,还介绍了我们最近发明的一种独特的交联方法,用这种方法所制得的磺化聚酰亚胺和磺化聚硫醚砜交联膜装在单电池上显示出良好...     

磺化聚醚砜膜的制备及其质子传导性能

以氯磺酸为磺化剂、浓硫酸为溶剂对聚醚砜进行磺化,得到具有良好亲水性能的磺化聚醚砜SPES膜。磺化度和湿度对磺化聚醚砜膜的电导率具有显著影响,磺化度为31.5%时,膜的电导率达到0.0163S.cm-1。当膜的亲水性能和吸水率增大,更多的水分子扩散到SPES的骨架体系中,并在含有-SO3H的亲水区之间形成水桥,有利于质子交换通道的形成和水合质子的传递,促进了电导率的提高。     

离子液体在质子交换膜中的应用研究进展

质子交换膜是质子交换膜燃料电池(PEMFC)的核心元件之一,以Nafion为代表的全氟磺酸膜的电导率强烈依赖于水含量,而以磺化聚醚醚酮(SPEEK)为代表的磺化芳香族聚合物膜电导率依然有需要改善的空间,这些限制了PEMFC进一步的发展.离子液体具有较高的电导率,优异的热稳定性、电化学稳定性,且不挥发,因此可以替代水在高温下作为质子传递介质,应用于传统质子交换膜性能提升的改性,提高膜的质子电导率和使用温度.文章对近年来离子液体在SPEEK、PS、PBI、PI、PVDF、Nafion等树脂中的应用及质子传递机理进行了综述,阐述了应用中存在的问题及对策,并对研究前景进行了展望.     

燃料电池用质子交换膜的发展方向

从Nafion膜的结构与性能的关系出发，主要分析了含水量、分子结构以及膜的微观结构和酸度对质子电导率的影响，指出了Nafion膜待克服的问题如高温电导率低，甲醇渗透性大，提出了质子交换膜以后的发展方向，包括Nafion膜的修饰与改性，含氟高分子作为主链接枝带有磺酸的支链，有机聚硅氧烷主链接枝烷基磺酸质子交换膜．     

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.     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

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.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

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 ...