自催化方式制备的ZnO一维纳米结构

ZnO一维纳米材料由于在压电、光电等方面的优良性质,正引起广泛的关注.介绍了目前不用催化剂合成ZnO一维纳米结构的几种方法,其中包括热蒸发方法、金属-有机物化学气相沉积方法(MOCVD)和自组装生长等,同时对合成的一维ZnO纳米结构进行了分析,简单地比较了这几种制备方法的优劣.     

纳米结构氧化锌的制备新方法

介绍了一种在纯水环境中水热法合成纳米结构ZnO的新方法，讨论了该方法制备纳米ZnO的生长机理和影响因素。通过扫描电镜检测可知，合成的纳米结构ZnO形貌均一，晶形规则。由荧光光谱可知，合成的纳米结构ZnO在370nm左右有典型的较窄的本征激发光峰，在500－550nm有宽泛的深能级激发光峰。     

溶液生长ZnO一维纳米阵列及其复合纳米结构的研究进展

对溶液生长ZnO一维纳米阵列的研究进展进行了评述,分析了晶种制备和溶液生长过程中各工艺因素对阵列微观形貌的影响,并介绍了在溶液中通过控制定点成核并利用有机基团调控ZnO晶体生长习性的合成路线用于构筑ZnO复合纳米结构的最新研究,指出了溶液生长ZnO一维纳米阵列和构筑复合结构中存在的问题及今后的研究方向.     

基于ZnO纳米带的纳米器件

ZnO作为一种被人们广泛研究的具有优良性质的半导体材料，在具有了纳米带状结构之后，展现出了更多的奇特性质。主要介绍了ZnO纳米带的合成以及ZnO纳米带二板管、激光器、微悬臂和声学谐振器等4种基于ZnO纳米带的纳米器件的制作及其性能的研究。     

纳米结构氧化锌的制备新方法

介绍了一种在纯水环境中水热法合成纳米结构ZnO的新方法,讨论了该方法制备纳米ZnO的生长机理和影响因素。通过扫描电镜检测可知,合成的纳米结构ZnO形貌均一,晶形规则。由荧光光谱可知,合成的纳米结构ZnO在370nm左右有典型的较窄的本征激发光峰,在500~550nm有宽泛的深能级激发光峰。     

基于ZnO纳米带的纳米器件

ZnO作为一种被人们广泛研究的具有优良性质的半导体材料,在具有了纳米带状结构之后,展现出了更多的奇特性质.主要介绍了ZnO纳米带的合成以及ZnO纳米带二极管、激光器、微悬臂和声学谐振器等4种基于ZnO纳米带的纳米器件的制作及其性能的研究.     

球形纳米氧化锌的制备及应用研究

纳米ZnO作为一种直接宽带隙半导体材料,其尺寸小、比表面大,呈现出表面效应、体积效应等性质,给纺织品带来了抗紫外、阻燃、抗菌等性能。与一维、二维形貌相比,球形纳米ZnO因优良的抗紫外和光催化性能成为智能纺织品研究的重要材料。本文阐述了球形纳米ZnO的制备方法,包括传统合成法、绿色合成法,并对其在纺织品中的应用进行了分析和研究。     

掺杂氧化锌一维纳米结构的研究进展

氧化锌（ZnO）纳米结构的形态是已知纳米结构中最为多样的多功能材料之一，由于一维ZnO纳米结构在电子与光电子装置中如表面声波、光子晶体、光发射二极管、光电探测器、紫外激光器、生物／化学传感器、场效应晶体管等诸多领域均展现出其独特的物理化学性能，已经引起人们的极大研究热情．而选择不同元素掺杂为调节其电、光和磁性质提供了一种有效方法，对实际应用至关重要，因此一维纳米结构的掺杂日益成为研究和应用的焦点。按照掺杂方法和掺杂元素的不同，对目前ZnO一维纳米结构的掺杂进展进行了回顾，提出了掺杂工艺中存在的问题，并对其发展趋势及前景进行了展望。     

用于环境光催化的固载型ZnO纳米结构的研究进展

光催化技术是解决当今环境污染问题的最有效途径之一。氧化锌(ZnO)作为一种重要的n型宽禁带半导体,不仅具有优异的光电性质,而且包含丰富的纳米结构,在光催化领域受到广泛关注。通常用作光催化剂的ZnO纳米材料是以粉体形式呈现,使用后需经过离心和过滤等回收工序,还容易造成二次污染。将ZnO纳米结构固定在可以移动的基底上,形成固载型的光催化剂,可以避免上述麻烦。从基本"结构单元"的维度的角度出发,综述了用于环境光催化的固载型ZnO纳米结构,包括零维、一维、二维和三维结构。零维结构主要是固定后的纳米颗粒,一维和二维结构分别以纳米棒和纳米片阵列为主,三维结构由低维度形态组合而成,大多形成复杂的分级结构。最后对固载型ZnO纳米结构在环境光催化的实际应用中所面临问题和挑战进行了展望。     

不同纳米结构ZnO的化学液相法合成

利用分子氧和溴酸钾一步直接在溶液中氧化还原反应原位产生碱作为氧源来制备纳米结构ZnO。首先,在甲酰胺水溶液中,以锌箔作为锌源,在温和条件下分别合成了纳米棒/管构成的海蛰状ZnO。其次,在溴酸钾水溶液,以锌箔作为锌源,在近室温下合成了纺锤形ZnO。该方法具有反应条件温和,反应参数连续可调节,一步湿法直接合成的ZnO具有新颖微/纳米结构等优点。     

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 ...     

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.