挥发诱导自组装制备聚碳酸酯耐刮伤涂层

利用挥发诱导自组装法制备了聚碳酸酯(PC)有机-无机纳米复合耐刮伤涂层,考察了基材处理方式、自组装液组成、涂装工艺等因素对自组装涂层厚度、透明性及耐刮伤性的影响.实验发现,采用1,6-己二胺处理PC基材时,涂层与基材之间的附着力好,得到的涂层耐刮伤性好.利用可聚合阳离子表面活性剂(R-303)时,可以省略后续洗涤处理工艺,而不影响涂层的耐刮伤性.     

热喷涂激光预处理的应用与影响研究进展

综述了激光预处理技术在热喷涂中的应用研究进展,通过调整激光工艺对基体进行清理或刻蚀处理,能够完成对基体表面的净化与粗化,提升涂层服役性能。分析了激光预处理对涂层性能的影响,激光预处理后能增强涂层在基体表面的机械结合,改善涂层/基体界面润湿,降低孔隙率。明确了激光预处理在热喷涂中存在的问题,并展望了其应用前景与研究方向。      

具有自分层效应的环保型含氟环氧自分层涂层的制备与性能

采用具有优异拒水拒油表面性能的环保型“伞形”结构短氟碳链含氟聚合物与在极性基材上附着力强的环氧树脂共混,通过自分层技术,获得能一次涂装成型的梯度含氟涂层。采用接触角测试、X射线光电子能谱和能谱详细研究了自分层形成的梯度结构及分层机理;考察了溶剂选择、基材、树脂配比、分层时间和固化温度等因素对涂膜分层和涂膜性能的影响。研究表明,当静置分层时间为3h,固化温度为80℃,基材为极性基材(马口铁和玻璃板)时,该环保型自分层涂层既具有含氟聚合物的优良表面性能,又兼具环氧树脂的优异附着力。此方法为涂层材料既保持强附着力又实现表面优异的拒水拒油功能,提供了一条新的思路和途径。     

塑料卷镀吸附机理探讨

本文用表面能、界面能来说明真空蒸镀薄膜与基材的吸附机理。如薄膜与基材间的界面能越低，说明其键合越强，附着越牢固。基材表面事先经离子轰击或等离子处理形成的结构缺陷，将有利于降低界面能，增强附着力。     

低磁不锈钢表面处理工艺及防护涂层体系设计研究

研究了不同表面处理工艺对低磁不锈钢基材自身耐蚀性能及涂层附着性能的影响,通过电化学阻抗及耐阴极剥离性测试确定了适用于低磁不锈钢表面的防护涂层体系.研究结果表明,以棕刚玉为喷砂磨料对基材进行喷砂处理,不仅可以提高基材表面粗糙度,满足涂层高附着需求,同时可降低基材表面残留粒料对基材引起的电化学腐蚀.以环氧锌黄为底层的防护涂...     

聚碳酸酯低聚物改性碳纤维及其增强聚碳酸酯复合材料的性能EI北大核心CSCD

以双酚A(BPA)和碳酸二苯酯(DPC)为原料进行酯交换制备了低聚合度聚碳酸酯(PC),通过红外光谱(IR)、凝胶渗透色谱(GPC)等确认产物相对分子质量为5516,且具有较高的端羟基含量。采用溶液浸渍法以LPC为上浆剂对碳纤维(CF)进行表面修饰,并制备了碳纤维增强聚碳酸酯复合材料(CFRPC),考察了LPC和CF含量对复合材料拉伸强度和热导率的影响。结果表明,经过脱浆及氧化处理后的CF(OCF)在LPC的修饰作用下与PC基材的界面附着力更高,使复合材料的性能得到明显提高,拉伸强度和热导率最高可分别达到136.3 MPa和0.739 W/(m·k),同条件下比采用DCF(仅经过脱浆处理的CF)增强PC的拉伸强度和热导率分别提高了26.0%和8.8%。经扫描电镜图观察到了拉伸样条断面上的OCF表面包裹着均匀的树脂层,显示了PC与OCF之间较强的附着力。     

光学塑料表面有机硅耐划伤涂层的制备及其性能研究

采用溶胶-凝胶法,在有机玻璃表面制备了有机硅耐划伤光学涂层.用硅烷偶联剂预处理有机玻璃,可以增强涂层的附着力和提高涂层的均匀性.制备的有机硅涂层显示了优良的耐划伤、耐环境腐蚀性能.     

有机涂层附着机理及附着力提高方法综述

介绍了有机涂层的附着机理,包括机械咬合、物理吸附、化学吸附;讨论了拉开法、划圈法、划格法等附着力测定方法的优缺点;详细探讨了影响附着力的因素,如基材表面粗糙度、涂料粘度等,综述了提高附着力的方法,如使用附着力促进剂、基材表面处理等。     

等离子体预处理对镀铜涤纶针刺毡性能的影响

采用射频磁控溅射技术在PET针刺毡表面沉积了纳米结构Cu薄膜,试图利用等离子体预处理的方法来改善薄膜与基材之间的结合牢度。采用扫描电子显微镜(SEM)对低温等离子体预处理前后基材表面形貌的变化进行了分析,同时利用静态液滴形状观察法和接触角测试分析了等离子体处理前后样品的润湿性能。采用X射线能谱仪(EDX)对纳米结构Cu薄膜进行了元素分布及定量分析。结合抗静电性能测试,采用冷热循环试验研究了Ar和O2等离子体预处理对Cu薄膜结合牢度的影响。研究发现,低温等离子体预处理不仅能改善沉积Cu薄膜PET针刺毡的抗静电性能,还能提高膜-基结合牢度和基材的润湿性能。用O2等离子体处理时,膜-基结合牢度和润湿性能较好。     

脉冲激光沉积技术生长铜材碳基保护膜EI北大核心CSCD

用脉冲激光沉积技术制备三种结构的金属铜材碳基保护膜,分析了失效样品剥离面的微结构。结果表明,在室温条件下生长的碳基复合膜,碳化硅层增强了界面间结合力、避免了类金刚石内应力积累导致的脱落。优化的碳基复合膜牢固地附着在金属铜材上,通过了国军标《光学薄膜通用规范(GJB 2485-95)》中附着力和中度摩擦测试。碳基复合膜使金属铜基材样品表面的纳米硬度比铜基材提高了4倍,增强了铜基材的抗划伤能力。     

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 ...