旋转喷吹反应自生铝基复合材料的工艺及显微结构

在大气条件下向铝和铝－镁合金液体内部旋转吹入氧气，氧与铝、镁反应，生成的Ａｌ２Ｏ３和ＭｇＡｌ２Ｏ４陶瓷颗粒分布在基体金属中。自生的Ａｌ２Ｏ３颗粒尺寸为０．１￣３μｍ，ＭｇＡｌ２Ｏ４颗粒尺寸为５￣１０μｍ。     

TiO_2－Al－B系反应烧结制备的复相陶瓷和原位Al基复合材料

采用反应烧结方法，利用ＴｉＯ２，Ａｌ和Ｂ粉末间的放热反应在较低的温度下制备Ａｌ２Ｏ３－ＴｉＢ２复相陶瓷和原位生长Ａｌ２Ｏ３和ＴｉＢ２弥散粒子增强Ａｌ复合材料Ａｌ２Ｏ３－ＴｉＢ２复相陶瓷是密度ρ～０．８的多孔体，由尺寸约１０μｍ的生长单元构成晶粒，在陶瓷中还含有少量的Ａｌ３Ｔｉ．Ａｌ基复合材料中原位形成的Ａｌ２Ｏ３和ＴｉＢ２粒子尺寸小于２μｍ，在基体中呈现均匀分布，没有发现Ａｌ３Ｔｉ生成．这种原位Ａｌ基复合材料具有优于ＳｉＣｗ／Ａｌ复合材料的强度．     

原位生长陶瓷相增强Al基复合材料的界面、微观结构及性能

本文对原位生长Ａｌ_４Ｃ_３与外加ＳｉＣ颗粒混杂增强Ａｌ（Ａｌ_４Ｃ_３·ＳｉＣ／Ａｌ）和原位生长Ａｌ_２Ｏ_３、ＴｉＢ_２颗粒混杂增强Ａｌ（Ａｌ_２Ｏ_３·ＴｉＢ_２／Ａｌ）两种复合材料的界面、微观结构和性能进行了研究。原位生长陶瓷相在基体中呈均匀分布。Ａｌ_２Ｏ_３和ＴＩＢ_２为尺寸１０ｎｍ～２μｍ的颗粒，Ａｌ_４Ｃ_３为长度０．２μｍ，直径０．０２μｍ的棒状单晶体。原位陶瓷相和Ａｌ基体之间的界面是清洁的，不存在中间过渡层。Ａｌ_４Ｃ_３和Ａｌ之间可存在的取向关系．Ａｌ_２Ｏ_３和ＴｉＢ_２粒子与Ａｌ之间不存在取向关系。两种复合材料都表现出优于ＳｉＣ_ｗ／Ａｌ复合材料的强度。     

Al_2O_3颗粒粒径和含量对α-Al_2O_3/Cu复合镀层性能的影响

本文研究了复合电沉积法制备的α－Ａｌ２Ｏ３／Ｃｕ复合材料的性能和磨损特征，测定了Ａｌ２Ｏ３粒径在０．５～５μｍ，含量在４～１６％时Ａｌ２Ｏ３／Ｃｕ复合镀层的硬度和磨损率，用扫描电镜对磨损形貌进行了分析，并对其磨损机制进行了探讨。结果表明，镀层中硬度随Ａｌ２Ｏ３含量增加呈线性增长，且含大颗粒Ａｌ２Ｏ３镀层的硬度略高于小颗粒镀层，Ａｌ２Ｏ３颗粒含量和粒径大小对磨损率和磨损机制有显著影响。     

以超微细Al2O3作种子乙酸乙烯酯的乳液聚合的研究

研究了以超微细Ａｌ２Ｏ３作种子的乙酸乙烯酯的乳液聚合以及所形成的复合材料的显微结构。聚合动力学研究结果表明，乙酸乙烯酯的聚合速率随Ａｌ２Ｏ３的用量的增加而下降；用量一定时，聚合速率则随Ａｌ２Ｏ３的粒径减小而降低。扫描电镜照片显示，Ａｌ２Ｏ３的粒径大于１ｕｍ时，Ａｌ２Ｏ３与聚乙酸乙烯酯的界面上有明显的微裂缝，而粒径为０．１ｕｍ时，Ａｌ２Ｏ３能均匀地分散在聚乙酸乙烯酯中且无裂缝存在。ＤＴＡ结果表明，超     

常压烧结ZTM／Al2O3复合陶瓷的力学性能

采用干法成型、常压烧结工艺制得致密的ＺＴＭ／Ａｌ２Ｏ３复合陶瓷材料。通过引入大颗粒的氧化铝，使ＺＴＭ陶瓷（氧化锆增韧莫来石陶瓷）的力学性能有明显提高。组成２０Ｖｏｌ．％Ａｌ２Ｏ３－２０Ｖｏｌ．％ＺｒＯ２－ｍｕｌｌｉｔｅ陶瓷材料，其断裂韧性为６．０６ＭＰａ·ｍ＾１／２，抗弯强度为４０３ＭＰａ。实验结果表明：Ａｌ２Ｏ３的弥散强化和ＺｒＯ２的相变增韧及微裂纹增韧是ＺＴＭ／Ａｌ２Ｏ３陶瓷的主要增韧机理。     

TiO2—Al—B系反应烧结制备的复相陶瓷和原位Al基复合材料

采用反应烧结方法，利用ＴｉＯ２，Ａｌ和Ｂ粉末间的放热反应的较低的温度下制备Ａｌ２Ｏ３－ＴｉＢ２复相陶瓷和原位生长Ａｌ２Ｏ３和ＴｉＢ２弥散粒子增强Ａｌ复合，Ａｌ２Ｏ３－ＴｉＢ２复相陶瓷是密度ρ－０．８的多孔体，由尺寸小于２μｍ，在基体中呈现均匀分布，没有发现Ａｌ３Ｔｉ生成，这种原位Ａｌ基复合材料具有优于ＳｉＣｗ／Ａｌ复合材料的强度。     

Pd/γ-Al2O3复合催化膜的热稳定性

由溶胶凝胶法制备出Ｐｄ/γ－Ａｌ２Ｏ３催化膜及镧掺杂改性的Ｌａ/Ｐｄ/γ－Ａｌ２Ｏ３膜,研究了镧的掺杂对Ｐｄ/γ－Ａｌ２Ｏ３膜热稳定性的影响．用ＤＴＡ、ＸＲＤ、ＢＥＴ分别对膜的晶相和微孔结构(包括比表面积、孔径和孔容)进行了研究,结果发现:镧的掺杂明显提高了α－Ａｌ２Ｏ３的相变温度和高温下Ｐｄ/γ－Ａｌ２Ｏ３催化膜的热稳定性．Ｐｄ/γ－Ａｌ２Ｏ３经１１００℃处理５ｈ后,其比表面积、孔径和孔容分别为４．４６ｍ２/ｇ、３５．１ｎｍ和０．０５１ｃｍ３/ｇ,而经镧掺杂改性的Ｌａ/Ｐｄ/γ－Ａｌ２Ｏ３膜的比表面积、孔径和孔容分别为５１．６ｍ２/ｇ、７．２ｎｍ和０．１３８ｃｍ３/ｇ．     

原位Al_2O_(3pl)/Ce-TZP复合材料的显微结构与力学性能

研究了原位生长Ａｌ２Ｏ３片晶／Ｃｅ－ＴＺＰ复合材料的显微结构与力学性能．结果表明,只要烧结温度适当,引入原位Ａｌ２Ｏ３片晶可同时提高复合材料的强度和断裂韧性．在所研究的范围内,以含 １５ ｖｏｌ％Ａｌ２Ｏ３的复合材料有最好的强韧化效果,而增韧效果又比增强效果明显．如果烧结温度过低或者Ａｌ２Ｏ３含量过高,则复合材料的力学性能反而下降．原位Ａｌ２Ｏ３片晶／Ｃｅ－ＴＺＰ复合材料的强韧化机理为应力诱导相交增韧和片晶增韧,两者起到协同增韧的作用．     

高纯氧化铝制备新方法及其应用研究

采用高纯金属铝水解成的氢氧化铝为原料，研究了不同温度下其相变过程，比表面变化以及结构变化，探讨了α－Ａｌ２Ｏ３相变过程中细化晶粒的方法及制备透明氧化铝的可行性。实验结果表明，采用快速升温的办法在１３００℃可以得到一次颗粒０．２７μｍ的α－Ａｌ２Ｏ３，球磨后的平均粒度为０．５μｍ，在１８２０℃氢气气氛下烧结陶瓷的透光率达９２％，经过进一步提高可以用于制备透明氧化铝灯管。     

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.……     

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 ...     

Effect of Oxide Assisted Metal Nanoparticles on Microstructure and Morphology of Gallium oxide Nanowires

Several researches have been reported about the characteristic of β-Ga2O3 nanowires which was synthesized on nickel oxide particle. But indeed, recent researches about synthesis of β-Ga2O3 nanowires on oxide-assisted transition metal are limited to nickel or cobalt oxide catalyst. In this work, Gallium oxide (β-Ga2O3 ) nanowires were synthesized by a simple thermal evaporation method from gallium powder in the range of 700 - 1000℃ using the iron, nickel, copper, cobalt and zinc oxide as a catalyst, respectively. The β-Ga2O3 nanowires with single crystalline without defects were successfully synthesized at the reaction temperature of 850, 900 and 950℃ in all the catalysts. But optimum experimental condition in synthesis of nanowires varied with the kind of catalyst. As increasing synthesis temperature,the morphology of gallium oxide nanowires changed from nanowires to nanorods, and its diameter increased. From these results, we could be proposed that the growth mechanism of β-Ga2O3 nanowires was changed with synthesis temperature of nanowires. Microstructure and morphology of Synthesized nanowire was characterized by HR-TEM, FE-SEM, EDX and XRD.     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from