单丝拔出实验研究芳纶-环氧树脂界面相

用单丝拔出实验研究了以有机硅表面处理剂处理的Kevlar-49-环氧树脂体系界面相.从力一位移曲线可得到界面破坏强度、界面破坏能、界面摩擦功等界面参数.硅表面处理剂对三者的贡献不同,以2#处理剂处理的综合效果最好.     

改性酚醛树脂处理剂对石英纤维增强芳基乙炔复合材料性能的影响

采用改性酚醛树脂作为石英纤维表面处理剂来提高石英纤维增强芳基乙炔复合材料(SF/PAA)界面性能。通过性能测试,研究处理剂对力学性能和介电性能的影响。通过XPS和SEM分析方法,研究了酚醛树脂表面处理剂对复合材料界面官能团变化和微观形貌的影响。性能测试结果表明改性酚醛树脂处理剂可以显著提高PAA复合材料的力学性能和介电性能。XPS分析结果表明酚醛树脂处理后的石英纤维表面与酚醛树脂发生了化学反应,SEM研究表明酚醛树脂处理后的复合材料界面粘结性能得到显著提高。     

酚醛树脂表面处理剂对炭纤维增强环氧树脂复合材料界面强度的影响

采用酚醛树脂作为炭纤维表面处理剂, 可以显著提高多种炭纤维和环氧树脂界面强度。通过XPS、AFM、SEM和层间剪切强度等方法, 研究了不同浓度的酚醛树脂表面处理剂对炭纤维增强环氧树脂复合材料层间剪切强度、炭纤维表面元素和化学键组成的影响, 以及炭纤维增强环氧树脂复合材料断面微观形貌的变化。XPS和AFM分析结果表明酚醛树脂和炭纤维表面发生了化学反应, 而且酚醛树脂处理剂浓度越高, 和炭纤维表面发生反应的基团也越多, 表面越光滑平整, SEM和层间剪切强度研究表明酚醛树脂处理后的复合材料界面粘结性能得到很大的改善, 而且界面粘结性能强烈依靠处理剂浓度。      

纳米碳酸钙的负触变机理探究

以纳米碳酸钙填充邻苯二甲酸二辛酯(DOP)糊为研究对象,通过改变纳米碳酸钙表面处理剂的质量分数,考察DOP糊流变特性,研究糊体系负触变结构的形成机理。结果表明:随表面处理剂质量分数的增加,纳米碳酸钙表面羟基密度降低,活化率增大,颗粒分散性得到改善;当碳酸钙未经表面处理或处理剂质量分数超过4.5%时,糊体系中网络结构更新比破坏快,从而表现出负触变性。     

Kevlar－49芳纶纤维表面接枝改性

采用空气等离子体处理Ｋｅｖｌａｒ－４９并在活化处理后的纤维表面接枝聚丙烯酸（ＰＡＡ）、聚丙烯酸乙酯（ＰＥＡ）及丙烯酸和丙烯酸乙酯的共聚物（ＰＡＡ／ＥＡ）。单丝拔出实验研究表明，空气等离子体改性的Ｋｅｖｌａｒ－４９／环氧树脂体系的界面结合强度和界面破坏能均有明显提高，其中接枝了Ｐ（ＡＡ／ＥＡ）的Ｋｅｖｌａｒ－４９／环氧树脂体系的界面破坏能（５５Ｊ／ｍ２）比未改性体系的界面破坏能（２７．８Ｊ／ｍ２）提高了一倍。     

云母填充聚丙烯的界面和力学性质的研究

研究了云母填充聚丙烯体系,通过云母的不同表面处理改变填料的表面性质,以及添加接枝改性聚丙烯作为界面改性剂,考察了不同的界面状况对体系加工流动性以及材料力学性能的影响。实验结果表明,有机偶联剂等表面处理剂有助于填料的分散。带有机长链的处理剂可明显降低体系的熔体粘度,但力学性能未提高,表现出界面润滑效应。硅烷偶联剂处理的云母与聚丙烯熔体的加工混合能接近于未处理体系,但熔混后压制的试样抗张强度显著提高,表现出界面“偶联”效应。添加少量的马来酸酐接枝聚丙烯,与带氨基的硅烷偶联剂相配合,可使填充聚丙烯的抗张强度和断裂伸长都大大提高,表现出界面的强偶联作用。     

芳纶纤维／环氧树脂微复合材料的界面断裂

本文采用空气冷等离子体改性Ｋｅｖｌａｒ－４９表面。通过单丝拔出实验研究表明经过纤维表面改性改善了芳纶纤维／环氧树脂的界面结合情况；芳纶纤维／环氧树脂微复合材料￣ａ）的破坏有两种类型：破坏发生在界面和纤维的内聚破坏。     

聚丙烯腈基碳纤维的表面涂覆改性对其在树脂基体中分散特性的影响

以阴离子表面活性剂脂肪醇聚氧乙烯醚磷酸盐(AEOPK)为处理剂对聚丙烯腈(PAN)基碳纤维表面进行涂覆改性。通过接触角仪、法拉第筒、场发射扫描电子显微镜和X射线光电子能谱对碳纤维的表面性质进行了研究。测试结果表明,当处理剂的质量分数和吸附量分别为0.5%和3.5mg/g时,AEOPK可在纤维表面均匀分布,碳纤维在树脂基体中的分散性得到明显改善。分析了处理剂对碳纤维/环氧树脂复合材料弯曲性能的影响,发现经过涂覆处理后碳纤维/环氧树脂复合材料弯曲强度和模量较未处理的试样分别提高了3.11倍和1.90倍。研究表明,碳纤维界面间的润湿力和电荷斥力的增加,是其分散性和复合材料弯曲性能增强的主要原因。     

芳纶纤维／环氧树脂微复合材料的界面断裂

本文采用空气冷等离子体改性Ｋｅｖｌａｒ－４９表面。通过单丝拔出实验研究表明经过纤维表面改性改善了芳纶，纤维／氧化树脂的界面结合情况，芳纶纤维／环氧树脂微复合材料的破坏有两种类型，破坏发生在界面和纤维的内聚破坏。     

玻璃纤维增强PET工程塑料性能及界面研究

用红外光谱分析，扫描电镜，粘弹谱仪，差示扫描量热法及力学性能测试方法，考察了玻璃纤维增强聚对苯二甲酸乙二醇酯的界面情况及力学性能等，并分析了玻璃纤维表面处理剂对ＰＥＴ树脂及其界面粘结性的影响，结果表明，经偶联剂表面处理的玻璃纤维对ＰＥＴ树脂有明显的增强效应能显著提高ＰＥＴ工程塑料的力学性能及界面粘结强度。     

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.     

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.……     

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...     

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.     

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.     

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 ...