SiC_w／Al－Li－Cu－Mg－Zr复合材料压铸工艺的研究

本文利用挤压铸造法成功制备了ＳｉＣ_ｗ／Ａｌ－Ｌｉ－Ｃｕ－Ｍｇ－Ｚｒ复合材料。采用化学分析、电子探针和扫描电镜等分析测试手段对材料进行化学分析和组织观察。结果表明，所获得的复合材料样品中晶须分布均匀，各合金元素含量均可控制在成分设计范围内。拉伸试验结果表明，ＳｉＣ_ｗ／Ａｌ－Ｌｉ－Ｃｕ－Ｍｇ－Ｚｒ复合材料具有较优异的综合拉伸性能。     

SiCw／Al—Li—Cu—Mg—Zr复合材料压铸工艺的研究

本文利用挤压铸造法成功制备了ＳｉＣｗ／Ａｌ－Ｌｉ－Ｃｕ－Ｍｇ－Ｚｒ复合材料。采用化学分析，电子探针和扫描电镜等分析测试手段对材料进行化学分析和组织观察。结果表明，所获得得的复合材料样品中晶须分布均匀，各合金元素含量均可控制在成分设计范围内。拉伸试验结果表明，ＳｉＣｗ／Ａｌ－Ｃｕ－Ｍｇ－Ｚｒ复合材料具有较优异的综合拉伸性能。     

SiCw／Al－Li复合材料热挤压变形及其对组织和性能的影响

采用热挤压的工艺方法成功地对压铸态ＳｉＣｗ／Ａｌ－Ｌｉ－Ｃｕ－Ｍｇ－Ｚｒ复合材料进行二次加工，研究了挤压态复合材料的微观组织和性能。结果表明，ＳｉＣｗ／Ａｌ－Ｌｉ－Ｃｕ－Ｍｇ－Ｚｒ复合材料具有很好的热成形性能，挤压可有效改善复合材料的综合机械性能。     

SiCw／Al复合材料研究进展

综述了ＳｉＣｗ／Ａｌ复合材料的研究进展，内容包括ＳｉＣｗ／Ａｌ复合材料的制备工艺，组织与性能、界面结合状态和应用研究。     

SiCw／Al—Li复合材料热挤压变形及其对组织和性能的影响

采用热挤压的工艺方法成功地对压铸态ＳｉＣｗ／Ｌｉ－Ｃｕ－Ｍｇ－Ｚｒ复合材料进行二次加工，研究了挤压态复合材料的微观组织和性能。结果表明，ＳｉＣｗ／Ａｌ－Ｌｉ－Ｃｕ－Ｍｇ－Ｚｒ复合材料很好的热成形性能，挤压可有效改善复合材料的综合机械性能。     

SiC晶须增韧Al2O3及ZrO2（Y2O3）基陶瓷复合材料的抗热震行为

采用三点弯曲及扫描电镜等方法研究了ＳｉＣｗ／Ａｌ２Ｏ３，ＳｉＣｗ／ＺｒＯ２）及ＳｉＣｗ／Ａｌ２Ｏ３＋ＺｒＯ２（Ｙ２Ｏ３）陶瓷复合材料的抗热震性。结果表明ＳｉＣｗ的加入使Ａｌ２Ｏ３，ＺｒＯ２（Ｙ２Ｏ３）以及Ａｌ２Ｏ３＋ＺｒＯ２（Ｙ２Ｏ３）基体的抗热震性显著提高，Ａｌ２Ｏ３陶瓷基复合材料的抗热震性明显优于ＺｒＯ２（Ｙ２Ｏ３）陶瓷基复合材料。同时发现在Ａｌ２Ｏ３＋ＳｉＣｗ材料基础上再加入少量ＺｒＯ２９２     

SiC晶须增韧Al_2O_3及ZrO_2（Y_2O_3）基陶瓷复合材料的抗热震行

采用三点弯曲及扫描电镜等方法研究了ＳｉＣｗ／Ａｌ２Ｏ３、ＳｉＣｗ／ＺｒＯ３（Ｙ２Ｏ３）及ＳｉＣｗ／Ａｌ２Ｏ３＋ＺｒＯ２（Ｙ２Ｏ３）陶瓷复合材料的抗热震性．结果表现ＳｉＣｗ的加入使Ａｌ２Ｏ３、ＺｒＯ２（Ｙ２Ｏ３）以及Ａｌ２Ｏ３＋ＺｒＯ２（Ｙ２Ｏ３）基体的抗热震性显著提高，Ａｌ２Ｏ３陶瓷基复合材料的抗热震性明显优于ＺｒＯ２（Ｙ２Ｏ３）陶瓷基复复合材料．同时发现在Ａｌ２Ｏ３十ＳｉＣｗ材料基础上再加入少量ＺｒＯ２（２Ｙ）颗粒（１０Ｖｏ１％），也可进一步提高Ａｌ２Ｏ３＋ＳｉＣｗ材料的抗热震性．     

SiCw／Al复合材料中SiCw的空间取向函数

通过理论分析,建立了ＳｉＣｗ／Ａｌ复合材料中ＳｉＣｗ的平面取向函数与空间取向函数的关系,研究了压铸态及挤压ｉＣｗ／Ａｌ复合材料中ＳＳｉｃｗ的平面间取向函数。结果表明,复合材料中ＳｉＣｗ平面取向函数与空间取向函数存在明显差咖;其中空间取向函数代表复合材料中ＳｉＣｗ的实际取向分布状态,与复合材料中的各工异相符合。     

SiCw／6061Al复合材料温度循环拉伸变形行为

本文采用热循环拉伸试验方法研究了ＳｉＣｗ／６０６１Ａｌ复合材料的变形行为。结果表明，ＳｉＣｗ／６０６１Ａｌ复合材料温度循环拉伸变形行为与蠕变类似分为初始变形阶段、稳态变形阶段和快速断裂三个阶段；温度循环拉伸变形稳态流变速率明显提高；温度循环拉伸变形的应力指数低于恒温蠕变的应力指数。     

热循环拉伸SiCw／6061Al复合材料变形与断裂行为研究

研究了热循环拉伸ＳｉＣｗ／６０６１Ａｌ复合材料变形与断裂过程，结果表明，热循环产生的界面应力有且于ＳｉＣｗ／６０６１Ａｌ复合材料的塑性变形；热循环低应力拉伸变形主要是位错的攀移；快速冷却时的过饱和空位既有助于位错的攀移，又能促进孔洞长大。     

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.     

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 ...