冷轧态SiCp/LY12复合材料超塑性及变形机制

研究了冷轧态ＳｉＣ颗粒（ｄｐ＝１０μｍ）增强ＬＹ１２复合材料（ＳｉＣｐ／ＬＹ１２）的超塑性,着重探讨了变形机制。研究表明：（１）在温度Ｔ＝８０３Ｋ（比熔点高２６Ｋ）,初始应变速度ε０＝４．８×１０＾－４ｓ＾－１时,应变速度敏感系数ｍ值为０．４９,延伸率达２４０％;（２）超塑性变形后的晶粒尺寸约为１０μｍ;（３）该事材料超塑性变形的主要机制是晶界液相和基体中动态回复调节的但却受界面液相和界面扩散流释     

温轧态2618A铝合金高应变速率超塑性的研究

对温轧态２６１８Ａ铝合金在不同温度（４７０～５５０℃）和应变速率为１０￣（－３）～１０￣（０）ｓ￣（－１）范围内的超塑性进行了研究，确定了最佳超塑性变形规范：在５００～５３０℃温度范围内，应变速率为２．８×１０￣（－１）ｓ￣（－１）的条件下，可获得大于２３０％的延伸率，表明该合金具有高应变速率超塑性的特性。     

压力浸渗SiCW/LY12复合材料的超塑性

对压力浸渗、小挤压比挤压以及进一步扎制制备的β－ＳｉＣ晶须增强ＬＹ１２铝基复合材料的超塑性变形行为进行了研究。研究表明：该复合材料在温度７８８￣８０８Ｋ、初始应变再率为３．３×１０＾－３￣３．３×１０＾－２ｓ＾－１的条件下超塑性变形时,延伸率为２００％￣３７０％。     

温轧态2618A铝合金高应速率超塑性的研究

对温轧态２６１８Ａ铝合金在不同度温（４７０－５５０℃）和应变速率为１０＾－＾３－１０ｓ＾０＾－＾１范围内的塑性进行了研究，确定了最佳超塑性变形规范：在５００－５３０℃温度范围内，应变速率为２．８×１０＾－＾１ｓ＾－＾１的条件，可获得大于２３０％。的延伸率，表明该合金具有高应变速率超塑性的特性。     

工业铯钟速率变化主要因素的探讨

上海天文台（ＳＯ）原子时实验室的４台工业铯钟１９８３～１９９０年连续工作了４或７年，它们的速率的长期变化与钟房的环境参数和性能参数的变化有关。本文根据有关数据，用不同的方法进行了分析，得到了一些明晰的结果。１）钟的速率变化受湿度的季节性变化影响：在相对湿度变化１％时，Ｃｓ２（１２６７）和Ｃｓ４（１４５７４）的速率变化分别为１．８９５ｕｓ／ｄ（２．２×１０－１４）和０．６１８ｎｓ／ｄ（７．１×１０－１５）。ＳＯ的原子钟房的相对湿度的年变化为２０％～８５％，引起这两台钟的速率年变化分别为１．４３×１０－１２和４．６５×１０－１４２）钟的速率变化受钟的离子泵电流参数的线性变化（从钟束管寿命的中期开始）影响：在离子泵电流参数变化１μＡ时，Ｃｓ３（１６１８０）和Ｃｓｌ（１２９９７）的速率变化分别为０．４３９ｎｓ／ａ（５．０８×１０－１５）和０．５５２ｎｓ／ａ（６．３９×１０－１５）。这两台钟的离子系电流参数的年变化分别为１６．４７μＡ／ａ和６．５３μＡ／ａ，引起的频率漂移率分别为１．６７×１０－１３／ａ（０．０３９５ｎｓ／ｄ２）和８．３×１０１４／ａ（０．０１９７ｎｓ／ｄ２）     

O＋HO2反应碰撞的理论研究

使用多体项展式分析势能函数，研究了Ｏ＋ＨＯ２反应碰撞的经典轨迹，指出存在二个反应通道，即（１）Ｏ＋ＨＯ２→ＯＨ＋Ｏ２和（２）Ｏ＋ＨＯ２→ＨＯ２＋Ｏ。在室温下，求得反应（１）的近似速度常数为（４．１±０．０６）×１０＾－１１ｃｍ＾３·ｍｏｌｃｃｕｌｅ＾－１·Ｓ＾－１，与实验值（５．４±０．９）×１０＾１１符合甚好；反应（２）的速度常数为５．４×１０＾－１３。对反应（１），总能量的７２．５％分配于产物     

室温应变速率及Al含量对FeAl合金拉伸性能的影响

研究了初始应变速率在１．３９×１０＾４￣６．９５×１０＾－１ｓ＾－１范围内Ｆｅ－４０Ａｌ的室温拉伸性能。结果发现，应变速率对ＦｅＡｌ合金室温下的断裂延伸率屈服强度和抗拉强度均有不同程度的影响，其中对断裂延伸率的影响最为显著。应变速率对ＦｅＡｌ合金力学性能的影响程度还与Ａｌ含量有关，Ｆｅ－３６．５Ａｌ较Ｆｅ－４０Ａｌ合金受应变速率的影响更大，研究结果还表明，Ａｌ含量还影响着ＦｅＡｌ合金拉伸断口中穿晶     

SiC_p/2024Al复合材料的超塑性能及断口形貌

熔铸法（IM）制备的SiC颗粒（14μm）增强2024Al复合材料经轧制成材后，在490、510、520和530℃下，初始应变速率在167～10－4~1．67×10－3s-1的范围内进行了超塑拉伸试验结果表明，在520℃、初始变应速率为8．33×10－4s－1时，超塑延伸率最大，为290％，m值约为0．49．同时，利用扫描电镜观察断口形貌，分析了变形机理     

聚苯硫醚合成反应的动力学研究

以脱水硫化钠和对二氯苯为单体，在六甲基磷酰三胺溶剂中常压下研究了聚苯硫醚合成的反应动力学。结果表明，该聚合反应符合二级反应动力学规律，在１８２、１９２、２０２和２１２℃条件下的聚合反应速率常数分别为１．７５×１０~（－４）、３．０２×１０~（－４）、５．５６×１０~（－４）和１．３１×１０~（－３）ｋｇ／ｍｏｌ·ｓ，反应的活化能为１２３ｋＪ／ｍｏｌ。     

低温下固体材料导热系数的测定

研制了一套能在４～３００Ｋ温区和１×１０￣（－４）～１×１０￣２Ｗ．ｃｍ￣（－１）·Ｋ￣（－１）导热系数范围内，测出各种固体材料导热系数的装置。本文介绍了装置的原理、结构、几种工程材料导热系数的测试结果。该装置具有结构简单、操作方便等优点。     

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