煤系高岭土/二甲基亚砜插层复合材料研究

以煤系高岭土为主要原料、二甲基亚砜(DMSO)为插层剂,制备出煤系高岭土/DMSO插层复合材料。利用X射线衍射、红外光谱和差示扫描量热-热重分析对插层复合物进行了研究。结果表明,DM-SO分子成功地插入了高岭石层间,与高岭石的内表面羟基形成新的氢键,并使高岭石的层间距从0.714nm增大至1.121nm,脱羟基温度由541℃左右降低至523℃。煤系高岭土/DMSO插层复合体于197℃左右发生DMSO的脱嵌作用。     

插层高岭土/改性氧化钛纳米复合颗粒及其电流变性能

采用插层法制备出甲酰胺插层高岭土,然后通过液相沉积法制备了插层高岭土/改性氧化钛纳米复合颗粒.XRD、FT-IR测试结果表明极性物质甲酰胺很好的插入层状黏土高岭土中,且插层率受反应时间影响显著.SEM照片证实了改性氧化钛包覆于高岭土上.该纳米复合颗粒所配电流变液具有较好的电流变效应,电流变效应受钛酸丁酯用量显著改变.通过介电性能解释了电流变液性能优良的原因,为制备高性能电流变液提供理论依据.     

原位聚合制备不饱和聚酯树脂/高岭土纳米复合材料及性能表征

利用超声法制备了高岭土-DMSO插层复合物前驱体,采取二步取代,原位聚合制备了不饱和聚酯树脂/高岭土纳米复合材料,并用XRD、FT-IR等手段对材料结构进行了表征,研究了纳米复合材料的阻燃性能。结果表明:当DMSO分子插入到高岭土层间时,d(001)值由0.717 nm增大到1.12 nm,插层率为91%,而不饱和聚酯树脂取代DMSO进入高岭土层间后,表征层状结构的d(001)特征衍射峰完全消失,高岭土内表面羟基吸收特征峰(3651 cm-1)和DMSO两个甲基的对称和反对称伸缩振动的吸收特征峰消失。燃烧实验表明这种材料相比纯树脂具有更好的阻燃性能。     

熔盐法合成金属氯化物-石墨插层化合物的判据

研究了熔融盐状态下金属氯化物-石墨层间化合物的合成判据.根据插层反应热动力学及化学键理论,选取元素的电负性和离子势作为键参数,并设计键参数函数λ为客体材料的遴选判据.基于键参数函数图对金属氯化物发生插层反应的难易程度和产物稳定性进行理论预估.研究结果表明:键参数函数图中λ≤1.2区域内的金属氯化物在700℃以下即可发生插层反应,且所得产物较为稳定;在1.2≤λ≤1.8区域内相应的客体材料在低温下很难单独插入石墨层间,常与低熔点氯化物形成共熔体后一起插入石墨层间;在λ≥1.8区域内大多为碱金属氯化物和碱土金属氯化物,理论分析认为这类物质的插层反应不适宜采用熔盐法.     

高岭土插层杂化材料的导电性研究

采用液相插层法，分别制备了高岭土/二甲基亚砜(K-DMSO)和高岭土/醋酸钾(K-KAc)插层杂化材料。探究了插层时间以及高岭土在反应混合物中的质量分数对杂化材料插层率的影响。通过交流阻抗法对杂化材料的电导率进行测定。结果表明：K-KAc插层杂化材料具有较好的导电性，在湿度为100%时，K-DMSO在室温下的电导率即可达到10^-3S/cm以上。     

二元有机/煤系高岭土复合相变储能材料的制备及其热性能

采用熔融插层技术,以二甲基亚砜(DMSO)改性的煤系高岭土为前驱体,将月桂酸(LA)和月桂醇(LAL)作为相变材料插入高岭土(Kaolin)层间,制备二元有机/煤系高岭土复合相变储能材料。采用XRD、FTIR、DSC等现代测试技术对复合材料的热性能与内层结构进行了研究。结果表明LA-LAL/kaolin复合物相变温度为25.1℃,相变焓为45.24J/g;复合相变材料是煤系高岭土和月桂酸/月桂醇二元体系的物理共混物,没有新的键合生成;热稳定性实验表明,煤系高岭土对月桂酸/月桂醇二元低共熔相变材料具有良好的定形效果。     

聚合物/高岭土插层复合材料的研究进展

聚合物/高岭土插层复合材料显示出优异的性能,但高岭土特殊的晶层结构则有碍于其与聚合物的插层复合,其复合材料的研究已受到关注。综述了聚合物/高岭土插层纳米复合材料制备方法、液态插层机理和表征技术的研究进展,并展望了其发展前景。     

生色基团插层锌铝水滑石的制备和性质

以层状锌铝水滑石为主体, 在乙二醇介质中, 通过离子交换法, 将一对具有给体－受体性质的生色团香豆素-3-甲酸(3-CCA)与9-蒽甲酸(9-ACA)共插入到层状锌铝水滑石层间, 组装得到晶体结构良好的共插层类水滑石, 且通过控制离子交换的时间、温度、客体投料比, 可制得一系列具有不同摩尔比客体的共插层产物. 产物采用XRD、IR、TG-DTA等测试技术进行结构表征, 采用UV-Vis吸收光谱和荧光光谱研究其光谱特性. 结果表明, 给体受体进入层间后, 不仅客体与主体层板存在静电力和氢键相互作用, 而且在限域空间内有利于客体之间的相互作用, 从而产生了给体受体间的能量转移过程.     

聚苯胺-高岭土纳米复合材料的制备与表征

苯胺分子中的氨基-NH_2可与高岭土层间氧原子或羟基—OH形成更强氢键,发生插入反应而“溶胀“。过硫酸铵引发苯胺原位聚合,成功制备了聚苯胺—高岭土纳米复合粉体。经粒度分析、SEM、XRD和导电率测定等手段,表征了复合粉体的结构与性能。结果表明:当高岭土含量达50wt.%时,复合材料的体积电导率为:0.253 S/cm。表观粒度与高岭土相比有较大幅度的提高,但分布变窄。由于层状高岭土的诱导作用,使聚苯胺的结晶度提高,聚苯胺与高岭土之间不是简单的混合,存在氢键相互作用。高岭土层间受限环境和聚苯胺与高岭土之间的氢键自组装,高岭土层间羟基—OH对聚苯胺有质子掺杂作用,使聚苯胺的结构与性能发生了变化。     

高岭石/2-吡嗪羧酸插层化合物的制备及其铁电性质

本研究试图以高岭石为主体材料,制备一类新的有机-无机杂化铁电材料.具体做法是以杂环化合物2-吡嗪羧酸为客体,在高压釜中制备高岭石/2-吡嗪羧酸插层化合物,该产物经X射线衍射(XRD)、红外光谱(IR)、热分析曲线(TG)表征和铁电性质测试,并通过CASTEP程序计算优化获得可能的插层结构.研究结果表明:依靠体系自增压,2-吡嗪羧酸分子在160℃、10 h条件下可插入高岭石层间,撑大其层间距至1.39 nm,插层率为42.73％;客体分子以几乎垂直方式定向于高岭石层间;该化合物具有室温铁电性和一定的热稳定性(<100℃).     

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.……     

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.     

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 ...