粉煤灰制备SiO_2气凝胶及其复合材料的研究进展

气凝胶材料因其具有独特的性能而成为当今国际新材料领域的研究热点。简要分析了我国目前的粉煤灰利用状况,详细综述了国内外利用粉煤灰为硅源,采用溶胶-凝胶法和常压干燥法制备SiO2气凝胶材料的研究进展,列举了SiO2气凝胶在各个领域的应用现状,指出了当前研究中存在的问题以及未来的研究方向,并展望了利用粉煤灰制备SiO2气凝胶材料的研究与应用前景。     

超级绝热材料SiO2气凝胶的制备及应用

介绍了超级绝热材料SiO2气凝胶的特殊纳米结构和超级绝热性能,对SiO2气凝胶新的制备方法和应用前景进行了综述,并指出SiO2气凝胶的未来研究重点和方向。     

气凝胶材料的研究进展

三维纳米网络结构的气凝胶材料具有许多独特的性能,在光学、热学、声学、微电子学、高功率激光等诸多领域具有广阔的应用前景,是目前材料科学研究领域的热点之一。主要从气凝胶的结构、制备机理、干燥工艺、改性以及应用等方面综述了气凝胶材料的研究进展,并展望了其今后的研究发展方向。     

硅气凝胶纳米材料的力学性能与增韧

本文综述了低温超临界干燥制备的块状硅气凝胶纳米材料的力学性能特征，论述了材料密度与硅气凝胶的力学性能的关系。从材料的制备过程出发，指出了控制裂纹和提高硅气凝胶韧性的一些方法。简介了硅气凝胶纳米材料的制备与应用，讨论了热处理过程以及材料的微观结构对硅气凝胶材料强度和韧性的影响，给出了初步的结论     

溶胶—凝胶法的研究和应用现状

简述了溶胶－凝胶法的基本原理，全面概述了溶胶－凝胶法的研究和应用现状，已有的研究表明，此法是一种有前途的制备新型材料的新方法，指出了今后溶胶－凝胶法研究的方向。     

碳/掺杂碳气凝胶及其研究进展

经溶胶-凝胶、超临界干燥和高温碳化过程制备的碳气凝胶及通过掺杂获得的掺杂碳气凝胶是一种新型的轻质纳米多孔材料,具有许多优异的性能和广阔的应用前景.介绍了溶胶-凝胶法的反应机理,综述了碳/掺杂碳气凝胶的制备方法、发展现状,指出了目前存在的问题并提出了新的可行的制备掺杂碳气凝胶的方法.     

纤维素基气凝胶材料及其应用研究进展

现代工业的快速发展,石油基聚合物过度消耗引发了非可再生资源短缺和环境污染双重危机,同时也激发人类利用天然高分子材料创造绿色新材料。纤维素作为地球上当今自然界中储量最大的天然高分子原材料,由于其极强的可再生性,广泛的应用,低廉的成本,良好的生物相容性和易降解性备受关注。与此同时,纤维素气凝胶作为继无机气凝胶及杂化聚合物气凝胶之后逐渐兴起的第三代气凝胶材料,在兼具传统气凝胶高比表面积、高孔隙率、低密度性质基础上融入纤维素材料可重复再生、易降解、相容性好等特性,同时还具备了良好的机械性能和延展性,在隔热、吸附、催化、电磁、生物医药等领域具有广泛的应用前景,成为了新材料研究的热点之一。从纤维素的溶解及纤维素基气凝胶材料的制备与改性入手,介绍了纤维素基气凝胶的性能提升及功能性开发最新研究结果,综述了纤维素基气凝胶材料在不同领域应用进展,并对纤维素基气凝胶材料的未来发展进行展望。     

复合型碳气凝胶在应变传感器中的应用进展EI北大核心CSCD

碳气凝胶是一种具有三维多尺度结构的新型轻质多孔材料,其特点是高比表面积、高孔隙率、低密度、高耐热和导电性。当前,碳气凝胶在应变传感器、超级电容器、电磁屏蔽、吸波材料、隔热防火、高效吸附等领域有广泛的应用研究。文中介绍了碳气凝胶的制备方法,包括溶剂热还原法、冷冻干燥法以及模板法;综述了几种复合型碳气凝胶在应变传感器上的应用;对复合型碳气凝胶制备应变传感器的发展方向进行了展望。     

增强改性SiO2气凝胶复合材料的研究进展

SiO₂气凝胶是一种含有纳米介孔结构的轻质固体材料，具有高孔隙率、高比表面积、低导热性、低介电性等特性，在隔热、吸附、吸声、发光、催化、电子等工业领域具有广阔的应用前景。但SiO₂气凝胶自身孔结构存在易碎、易坍塌等缺陷，导致应用受到较大限制。在保持SiO₂气凝胶良好特性的前提下，对其进行增强改性制备力学性能优良的SiO₂气凝胶复合材料是近年来的研究热点。本文报道了无机/有机纤维增强改性SiO₂气凝胶、有机聚合物增强改性SiO₂气凝胶及无机物掺杂增强改性SiO₂气凝胶等复合材料的主要制备工艺过程、材料综合性能表现及增强改性机制，探讨了增强改性SiO₂气凝胶复合材料研究进展及重点方向，以期为增强改性SiO₂气凝胶复合材料的研究和应用提供新的设计思路。      

氧化硅气凝胶隔热复合材料研究进展

氧化硅气凝胶由于纤细的纳米结构,具有极低的热导率,是一种新型轻质保温隔热的理想材料。但其力学性能和高温遮挡红外辐射能力差限制了气凝胶在该领域的应用。通过添加增强体和遮光剂研制气凝胶隔热复合材料是主要的解决方法。本文综述了近年来气凝胶隔热复合材料的制备方法,重点分析了气凝胶复合材料在力学性能和隔热性能方面的研究进展,并指出了存在的问题,对今后的研究提出了展望。     

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.……     

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...     

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.……     

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.     

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.     

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