TiNi形状记忆合金阻尼特性的研究

在变频、变温条件下，对两种热处理方式处理的Ti-50．8Ni(原子分数，％)合金的低频阻尼特性进行了研究，结果表明：中温退火处理的Ti-50．8Ni合金的阻尼性能好于高温固溶时效处理的合金；马氏体相、R相阻尼高于母相阻尼，相变过程(多相共存)出现阻尼峰，远远高于母相、马氏体相阻尼，同时伴随有最小弹性模量峰，即相变时材料出现软化现象；相变时阻尼与频率成反比，频率越高，相变阻尼峰越不明显，频率对弹性模量变化几乎没有影响；相变结束合金的阻尼对温度及频率不敏感；中温退火处理的Ti-50．8Ni合金在降温过程中由于温度和应力的复合作用导致多次相变，出现受频率影响的多个相变阻尼峰。     

高阻尼TNCH合金的相变与阻尼性能研究

研究了新型阻尼合金的马氏体相变、内耗以及它们之间的关系。结果表明,在室温低频范围内合金主要经历了3个阶段:低温马氏体状态,两相共存状态与母相状态。低温马氏体时,TNCH合金的高阻尼主要由B19′马氏体变体、孪晶界面产生。相变过程中的阻尼特性与相变时新相/旧相的相界面数量有关。合金处于母相时其阻尼主要来源于合金的晶体缺陷。     

高锰γ-MnFe合金双程形状记忆效应

以γ-MnFe高锰(Mn＞80%(原子分数)) 合金为研究对象,研究探索γ-MnFe合金的双程形状记忆效应(TWSME) .通过TEM和热膨胀法,研究不同预应变下γ-MnFe合金的TWSME.通过测量不同预应变条件下合金形状恢复率的变化,来研究γ-MnFe基合金的双程形状记忆效应和双程恢复量etw的影响因素,最后对1.6%预应变试样进行热循环训练,用DSC测量合金马氏体相变Ms和逆相变Af,发现热滞为2K,几乎达到无热滞的形状记忆效应.研究显示经过训练后的高锰γ-MnFe合金形状回复无热滞是由于二级反铁磁转变耦合一级马氏体相变,使得马氏体相变与逆相变热滞几乎为0.     

液晶苯酚酯相变的研究

用低颅内耗及ＤＳＣ方法研究了反－４－丁基环己基甲酸－（４－丙基）环己基苯酚酯液晶的相变,通过比较低频内耗与ＤＳＣ的激活能。证实了液晶相变内耗峰的存在,论证了相变内耗峰的产生机制。     

共析成分Zn-Al合金的相变内耗和DSC的研究

利用低频内耗和示差扫描量热计（ＤＳＣ）等技术研究了共析成分Ｚｎ－Ａｌ合金共析转变过程中的能量耗散问题，发现相变潜热和热滞均与相变的路径有关。相变内耗峰的峰高与频率倒数之间呈非线性关系，而对数减缩量与频率例数之间呈线性关系。证明了共析转变过程的内耗不仅具有滞弹性的性质，而且具有线性粘弹性的性质，相变内耗峰主要是线性粘弹性内耗的贡献。用Ｍａｘｗｅｌ模型对实验结果进行了解释。     

共析成分Zn—Al合金的相变内耗和DSC的研究

利用低频内耗和示差扫描量热计（ＤＳＣ）等技术研究了共析成分Ｚｎ－Ａｌ合金共析转变过程中的能量耗散问题，发现相变潜热和热滞均与相变的路径有关，相变内耗峰的峰高与频率倒数之间呈非线性关系，而对数减缩量与频率例数之间呈线性关系，证明了共析转变过程内耗不公具有粘滞弹性的性质，而且具有线性粘弹性的性质，相变内耗峰主要是线性粘弹性内耗的贡献，用Ｍａｘｗｅｌｌ模型对实验结果进行了解释。     

Fe-Ni-C合金中珠光体、贝氏体及马氏体的相变内耗

通过研究三种 Fe-Ni-C 合金中珠光体、贝氏体及马氏体的低频相变内耗,发现马氏体相变内耗遵守相界面位错的静滞后损耗机制,珠光体和贝氏体相变内耗不遵守这种机制。在频率基本不变时,随着冷却速度的增加珠光体和贝氏体的相变内耗峰增高,峰温降低,且 Q(?)和(?)/fm 件·T_m 呈正比线性关系;频率增加时,珠光体和贝氏体的内耗峰明显降低,峰温上串。在连续冷却条下,Fe-Ni-C 合金中开始珠光体及贝氏体相变时并不存在点阵软化现象。     

Cu元素对TiNiNb合金阻尼性能的影响

采用差示扫描量热仪(DSC)研究了不同原子百分比含量Cu元素(5%,15%,25%)取代Ni对TiNiNb合金马氏体相变温度的影响,并利用单悬臂法(动态机械分析仪)测试了这3种合金的阻尼性能.结果表明,Cu元素对TiNiNb合金相变过程没有明显的影响,在试验温度范围内,合金经历了一阶段的热弹性马氏体相变;Cu含量的增多促进了该合金相变温度的增加,使得相变主要发生在80℃～98℃之间(加热过程);在马氏体相区,Cu含量高,材料的阻尼性能越好.     

Pb(Ni1/3Nb2/3)O3-PbTiO3系统准同型相界附近的介电异常

用两步合成法制备了（１－ｘ）Ｐｂ（Ｎｉ１／３Ｎｂ２／３）Ｏ３－ｘＰｂＴｉＯ３（ｘ＝０．３０－０．４０）陶瓷,对其相结构和介电性能进行了研究。ＸＲＤ分析表明,准同型相界在ＰＴ含量ｘ＝０．３４－０．３８范围内。介电性能研究结果表明,组成在准同型相界处的试样,其介电常数呈现最大值,同时还发现,准同型相界处的陶瓷出现介电双峰,其中一个为驰豫型铁电相向顺电相转变的相变峰;另一个介电峰处于１３０－１５０℃的高     

Fe—17Mn—10Cr—5Si—4Ni合金低温应力诱发相变特点及其形状记？…

用Ｘ射线衍射分析、显微组织观察等研究了Ｆｅ－１７Ｍｎ－１０Ｃｒ－５Ｓｉ－４Ｎｉ合金在低温（低于室温）下应力诱发相变的特点及其形状记忆效应。合金在室温拉伸变形时,当应变量超过５％由于应力诱发ε马氏体的相变作用而形成的α′马氏体;当变形温度低于室温时应力优先诱发γ－α′马氏体转变。正是这种应力诱发相应特征的转变使合金的形状记忆效应在室温以下出现奇特低谷。     

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.     

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     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.     

新闻(英文)

正China and Greece Sign the Standardization Cooperation Agreement Witnessed by Chinese Premier Li Keqiang and Greek Prime Minister Antonis Samaras,AQSIQ Minister Zhi Shuping and ELOT Chairman and Executive Director Angelos Tolkas signed the SAC-ELOT Standardization Cooperation Agreement.The Agreement is one of the critical cooperation documents signed during Li Keqiang’s visit in Greece,encouraging China and Greece to