聚苯乙烯/氧化石墨纳米复合材料的制备与性能

利用十六烷基三甲基溴化铵对氧化石墨进行插层改性。以原住插层聚合的方式合成了聚苯乙烯／氧化石墨（PS／GO）纳米复合材料。用XRD和TEM进行的形态研究表明,氧化石墨被剥离成10nm-30nm厚的层片而分散在聚合物基体中。热重分析证明PS／GO复合材料比PS材料和普通石墨粉填充的PS材料表现出更好的热稳定性。     

共生沉积法制备自润滑铝阳极氧化复合膜

利用平均粒径1．07μm的MoS2微粒，在草酸溶液中用共生沉积法制备出自润滑阳极氧化铝复合材料．首次实验结果表明MoS2微粒进入阳极氧化膜的数量极少，主要是因为草酸阳极氧化膜微孔较小而MoS2粒径偏大．第二次实验，用研钵先对MoS2粒子进行40min的润湿分散研磨，结果制备得到自润滑阳极氧化铝复合膜，原因是研磨使MoS2的粒径变小，从而有较多的MoS2可以进入阳极氧化膜层．     

聚丙烯酰胺/氧化石墨纳米复合材料的研究

氧化石墨具有良好的层状结构，其层间具有丰富的官能团，能与有机聚合物形成插层纳米复合材料进而改善材料的性能．采用层离吸收-原位聚合法制备了聚丙烯酰胺／氧化石墨纳米复合材料，并采用XRD、HREM及DSC等对其结构和性能进行了表征。结果表明，聚丙烯酰胺与氧化石墨两者之间存在着较强的相互作用，材料的玻璃化转变温度得到提高，层离吸收-原位聚合法是获得聚丙烯酰胺／氧化石墨层纳米复合材料的有效途径，聚丙烯酰胺在氧化石墨中存在着多种排列方式，不同层间距(1．6nm和2．8nm)的聚丙烯酰胺／氧化石墨纳米复合结构同时存在。     

尼龙6/纳米TiO2及尼龙6/纳米Al2O3原位复合材料的性能

通过原位复合的方法合成了尼龙6／纳米TiO2和尼龙6／纳米Al2O3复合材料，并对材料的力学性能、动态力学行为和光氧化降解行为进行了初步的探讨。结果表明，经钛酸酯偶联剂表面处理的纳米TiO2和纳米Al2O3的加入，可以在一定程度上同时提高尼龙6基体的强度和韧性。此外，氙灯老化实验和XPS测试结果表明，尼龙6／纳米TiO2复合材料具有良好的耐光氧老化降解能力。     

蒙脱土/聚苯乙烯复合材料的热分解成炭行为

将聚苯乙烯(PS)树脂与不同种类蒙脱土(MMT)进行熔融复合制备MMT/PS复合材料, 通过X射线衍射(XRD)和高分辨透射电镜(HRTEM)对复合材料的微观结构进行了研究。采用SEM、 EDX、 XRD、 氧指数法和锥形量热法研究了复合材料的热分解成炭行为和燃烧性能。结果表明: 用蒙脱土原土(NaMMT)制备的NaMMT/PS复合材料是一种简单物理混合物, 用有机蒙脱土(OMMT)制备的OMMT/PS复合材料是一种插层-部分剥离型纳米复合材料。MMT与PS质量比为6:100时, OMMT/PS复合材料的热释放速率峰值和平均值分别只有NaMMT/PS复合材料相应值的70.7%和67.4%, 火灾性能指数(FPI)是后者的1.2倍, 氧指数比后者增加1.0%, 热分解残余物表面碳元素含量是后者的2.5倍。OMMT/PS复合材料热分解后在材料表面生成一层厚厚的致密、 连续的含碳硅酸盐残余物层, 起到良好的阻燃作用, 而NaMMT/PS复合材料几乎没有成炭能力, 其热分解产物全部来自NaMMT本身的热分解, 阻燃性能很差。     

MoS_2基复合材料的制备进展及其应用研究

MoS2独特的三明治结构使其具有良好的化学性质,以MoS2为基础的复合材料在负极、催化、润滑等方面都有着广阔的应用前景,它的制备和应用是目前我国的一个热点研究方向。综述了近年来纳米MoS2的制备方法,主要介绍了前驱体分解法、水热法、模板法、微波合成法和剥层重堆积法,研究了不同的反应条件对MoS2的影响。此外,阐述了以MoS2为基础的复合材料在负极、催化方面的研究进展,同时对它的前景做了展望。     

苯乙烯-丙烯酸丁酯/蒙脱土纳米复合材料的阻燃性

以乳液插层聚合法合成苯乙烯-丙烯酸丁酯／蒙脱土纳米复合材料。X射线衍射结果表明，聚合物能够有效地插层到经过有机化处理的蒙脱土层间，且蒙脱土片层可以均匀地分散在苯乙烯-丙烯酸丁酯共聚物中。TGA分析表明，苯乙烯-丙烯酸丁酯／有机蒙脱土纳米复合材料的热稳定性有所提高．锥形量热仪测试和研究表明。复合材料的燃烧性能，包括热释放速率和质量损失，在蒙脱土含量为2％时，效果最好。     

紫外光固化聚氨酯丙烯酸酯/蒙脱土纳米复合材料的制备与表征

采用原位聚合方法合成了可紫外光固化的插层型聚氨酯丙烯酸酯／蒙脱土复合材料,通过紫外光固化后制备了聚氨酯丙烯酸酯／蒙脱土纳米复合材料。利用FT-IR、XRD等对材料的结构、蒙脱土的插层和剥离行为进行了表征,采用TGA和应力-应变方法对复合材料的热学及力学性能进行了测试。结果表明,当蒙脱土含量为4％～5％时,聚氨酯丙烯酸酯／蒙脱土纳米复合材料的耐热性能有了明显提高,而拉伸强度和撕裂强度比纯聚氨酯丙烯酸酯分别提高了100％和50％。     

B4C—SiC／C复合材料高温自愈合抗氧化性能研究：Ⅱ 复合材料结构变化 …

用扫描电镜观察了复合高温氧化后的表面形貌，通过对复合材料断面ＳＥＭ考察获得了复合材料氧化后表面陶瓷层的厚度，据此对复合材料氧化过程中的结构变化与其自愈合抗氧化的相关性进行了分析。结果表明；８００℃氧化时，复合材料表面的陶瓷层主要由Ｂ２Ｏ３／ＳｉＣ粒子组成，复合材料中Ｂ４Ｃ含量高及Ｂ／Ｓｉ比大时，可实现较好的自愈合抗氧化；１０００℃氧化时，ＢＳ２０１０和ＢＳ２０２０复合材料样品表面形成了熔融流动性好     

羧甲基壳聚糖改性水基磁性液体的工艺研究

采用共沉淀法制备了药物载体羧甲基壳聚糖改性纳米四氧化三铁（Fe3O4）磁性液体。对一步法（合成Fe3O4颗粒和表面改性同时反应）和两步法（先合成再改性）制备的样品通过X射线衍射（XRD）、傅立叶红外光谱（FTIR）、扫描电镜（SEM）、热重分析（TG）和磁化曲线测定等表征分析比较。改性水基磁性液体性能稳定，改性Fe3O4纳米颗粒粒径在25nm左右，饱和磁化强度为0．36A·m^2/kg，热重和红外分析显示一步法改性表面包裹量多于两步法，结果表明一步法较适合用于制备羧甲基壳聚糖改性的磁性液体．     

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.……     

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 ...