纳机电系统

纳机电系统(NEMS)是基于微机电系统发展起来的新兴技术领域，同时也是纳米技术的重要组成部分．文中介绍了NEMS器件的微小尺寸、超高频率和超低能耗等重要特性，并列举了NEMS在生物、信息和纳米流体学等领域的应用．最后讨论了NEMS在发展中遇到的问题和涉及到的关键技术，如微观效应的影响，NEMS加工技术，NEMS的设计、仿真和优化，NEMS器件的驱动与检测，NEMS器件与宏观世界的通讯等．     

微机电系统(MEMS)与纳机电系统(NEMS)

微机电系统(MEMS)和纳机电系统(NEMS)是微米/纳米技术的重要组成部分.MEMS已经在产业化道路上不断发展,NEMS还处于基础研究阶段.本文强调了制造技术是微/纳机电系统发展的基础,在简单地介绍了典型的MEMS和NEMS器件和系统后,讨论了MEMS和NEMS发展中的几个问题和MEMS和NEMS的发展前景.     

微机械加速度计的研究现状综述

随着微机械加工技术的不断进步以及微机械加速度计市场占有率的逐步扩大,各种类型的微机械加速度计层出不穷,其中以电容检测式微机械加速度计发展的最为迅速且产业化水平最高,其次是压阻式、压电式、热对流式、隧道电流式、谐振式,以及近年来成为研究热点的光学式加速度计。本文详细阐述了国内外已报道的各种类型微机械加速度计的结构、原理、制造工艺和性能指标,并对不同精度微机械加速度计的产业化发展现状和市场应用情况进行了总结。新材料、新机理、纳米尺度、智能化以及更高的性能指标将是今后几年微机械加速度计的主要发展趋势,也将在MEMS/NEMS领域掀起新一轮的研究热潮。     

第一届IEEE纳米／微米工程及分子系统国际年会

第一届IEEE纳米／微米工程及分子系统国际年会（IEEE NEMS）将在中国珠海举行．IEEE NEMS是IEEE纳米技术委员召开的第一次会议，会议将召集世界顶尖学者就几个关于MEMS和纳米科技专题展开讨论，推动最新的研究成果的共享，促进跨领域学科信息、知识的互通，从而增进各技术领域的发展．微机电系统最终发展至纳米机电系统但同时对于构建完整的纳米器件及其系统又不可或缺．可以预见，在不远的将来微纳米科技将会发展成为影响全球发展和人类生活的重要技术之一．     

2005（第四届）中国纳米科技西安研讨会即将召开

今年9月即将在西安召开的“2005(第四届)中国纳米科技西安研讨会”前期工作进展顺利,目前回执确认的报名参会代表已达361人,预计到会400人左右。这次大会的主席为师昌绪院士和解思深院士。大会特邀中科院副院长、国家纳米科技中心主任白春礼,中国微米纳米技术学会副理事长解思深等17位院士、教授级学者作学术报告。报告主题为:纳米技术的最新发展动向;纳米技术的产业化现状与趋势;纳米材料(粉体、薄膜、纤维、碳纳米管、流体、块体等)的制备与特性;纳米材料(粉体、薄膜、流体、块体等)的应用与产业化;纳米电子技术与纳米器件;纳米医学与生命科学;微纳机电系统(MEMS、NEMS)技术;纳米能源技术;纳米信息技术;纳米加工技术;纳米测量技术;纳米科学技术的基础研究和交叉学科及相关领域。     

MEMS推动压力传感器发展未来市场将达236亿美元

正据美通社报道,Research And Markets发布了关于压力传感器市场的报告,该报告中增加了"按产品类型(绝对、仪表、差动、密封和真空)、技术(压阻、电容、谐振、电磁和光学)、应用、功能、最终用户行业和地理位置划分的2024年的全球压力传感器市场预测"的内容。纳米机电系统(NEMS)技术的进步、物联网     

世界首个全功能性的纳米管装置

据美国每日科学网报道，美国加州大学伯克利分校和伯克利实验室的研究人员通过打造世界首个全功能性的纳米管装置，成功建造了一个可以给金原子称重的纳机电系统（NEMS）。此成果发表在最新出版的《自然-纳米技术》杂志上。     

美开发质量传感器可给单个原子称重

美国加州大学伯克利分校和伯克利实验室的研究人员通过打造世界首个全功能性的纳米管装置，成功建造了一个可以给金原子称重的纳机电系统（NEMS）。此成果发表在最新出版的《自然一纳米技术》杂志上。加州大学伯克利分校物理系和伯克利实验室材料科学部的物理学家亚历克斯·泽特尔负责此项研究。     

纳米薄膜界面滑移现象的分子动力学模拟进展

随着先进制造技术的发展,许多精密系统中的薄膜厚度已经接近纳米量级。由于纳米尺度的特殊性,宏观尺度下的界面性质将不再适用,因此探索纳米尺度下的界面性质对于微机电系统(MEMS)甚至纳机电系统(NEMS)中涉及到的润滑薄膜研究具有非常重要的价值。Couette流动作为剪切驱动流动的原形,在研究薄膜界面滑移现象上具有较高的代表性。在总结国内外该方向研究成果的基础上,详细介绍和讨论了纳米尺度薄膜Couette流动的分子动力学方法,总结了现有的滑移现象和规律,并对今后的发展进行了展望。     

第一届IEEE纳米／微米工程及分子系统国际年会将在珠海召开

第一届IEEE纳米／微米工程及分子系统同际年会将于2006年1月18—21日在广东珠海召开。IEEE—NEMS是IEEE纳米技术委员召开的第一次会议。会议将召集世界顶尖学者就几个关于MEMS和纳米科技专题展开讨论，推动最新的研究成果的共享，促进跨领域学科信息、知识的互通，从而增进各技术领域的发展。     

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