用电沉积法制备纳米氧化锌/海藻酸钠复合膜

以海藻酸钠为稳定剂用水热法合成纳米氧化锌,再用电沉积法制备了纳米氧化锌/海藻酸钠复合膜。测试纳米氧化锌的粒径和化学结构、观察了复合膜的形貌并测试其性能。结果表明,纳米氧化锌/海藻酸钠复合膜对大肠杆菌和金黄色葡萄球菌有良好的抗菌性能,对亚甲基蓝染料有良好的光催化降解效应。     

氧化锌/石墨烯纳米复合材料制备技术的研究进展

氧化锌/石墨烯纳米复合材料在储能、光电材料与器件、光催化剂等方面具有广阔的应用前景,其所含元素无毒无害,储量丰富,适用于溶剂热法、超声空化法、电化学沉积等低成本非真空制备方法,故氧化锌/石墨烯复合材料近来成为复合材料领域研究热点之一。综述了氧化锌/石墨烯复合材料的多种制备方法,讨论了各制备方法的工艺特点与不足,分析了不同制备方法对氧化锌/石墨烯纳米复合材料形貌与性能的影响,展望了其未来工业化规模制备的发展趋势。     

不同催化剂表面定向生长单壁碳纳米管的研究

以不同含水量的乙醇为碳源,分别以Fe/Mo、Ag、Au为催化剂,采用化学气相沉积法制备了单壁碳纳米管.通过SEM,AFM,TEM等表征方法研究了碳纳米管的形貌和微观结构.结果表明,用Fe/Mo、Ag、Au均能长出高质量的碳管阵列,特别是Au的“Sputtering”法,可以不用繁琐地制备纳米颗粒催化剂便得到SWNT阵列...     

一维氧化锌纳米棒制备技术的最新研究进展

综述了一维氧化锌纳米棒制备技术的研究进展,着重介绍了氧化锌纳米棒的气相和液相合成方法.介绍了不同方法的反应特征、产物形貌及其性能,并对水热法、模板法、热分解前驱物法、离子液体分解法和化学气相沉积法的生长机理进行了描述,展望了一维氧化锌纳米棒的后续研究.     

碳纳米管/纳米铁颗粒杂化结构的制备及形成机理

采用催化化学气相沉积法将由C包覆的纳米铁颗粒(FeNP)原位沉积于碳纳米管(CNTs)表面并形成不同形貌的碳纳米管/纳米铁颗粒(CNTs/FeNP)杂化结构。使用扫描电子显微镜、透射电子显微镜对制备的杂化结构进行微观形貌分析和结构表征。结果显示,纳米铁颗粒通过石墨片层结构与碳纳米管相连,具有良好的界面结合。当噻吩的添加量较低时,产物中碳纳米管的直径减小,产量增多。当噻吩的添加量超过0.5%时,可以得到CNTs/FeNP杂化结构。使用X射线能谱仪、X射线衍射仪分析了杂化结构的成分及其相对含量,结果显示体系中的Fe主要以α-Fe、γ-Fe和Fe3C的形式存在,并且Fe的含量随噻吩含量的增加不断增加。通过研究纳米铁颗粒的形成及其在碳纳米管表面的沉积,揭示了CNTs/FeNP杂化结构的形成机理。     

碳纳米管MPCVD和TCVD制备的比较分析

碳纳米管主要的制备方法是化学气相沉积法(CVD).采用CVD法中最主要的微波等离子体化学气相沉积法(MPCVD)和热化学气相沉积法(TCVD)制备出定向的碳纳米管.并从制备工艺,场发射性能和SEM结构等方面对两种方法进行比较分析,得出对碳纳米管制备有一定指引和借鉴意义的结论.     

氧化锌纳米棒形貌对ZnO/Cu2O异质结太阳能电池光伏性能的影响

采用电化学沉积法制备了ZnO纳米棒,首先讨论了电化学沉积参数对氧化锌(ZnO)纳米棒形貌的影响,并对不同长度ZnO纳米棒的光吸收和反射等性质进行了研究.实验发现沉积时间是影响纳米棒长度、直径的重要因素,ZnO纳米棒的微观形貌对其光学性质有重要影响.然后以氧化锌纳米棒为n型材料,以氧化亚铜为p型材料,通过电化学沉积法构筑了ZnO/Cu2O异质结太阳能电池,并测试了其光伏性能,研究表明增长纳米棒阵列的长度使得开路电压、短路电流密度及光电转换效率等性能得到提升.最后,综合分析了氧化锌纳米棒形貌与所组装电池的性能之间的关系,发现调控氧化锌纳米棒的形貌是提高ZnO/Cu2O异质结太阳能电池光伏性能的有效途径.     

纳米ZnO/Zn/CNT多孔复合结构的制备及其对亚甲基蓝的无光催化降解

以碳纳米管(CNTs)为基础材料,聚甲基丙烯酸甲酯(PMMA)为造孔剂,构筑多孔结构,并将水解反应所得的氧化锌/锌复合纳米颗粒附着在孔隙结构中,制得氧化锌/锌/碳纳米管多孔复合结构,氧化锌纳米棒直径约30~60nm,长径比可达40。对复合结构的微观结构及成分表征显示,制备ZnO/Zn/CNT多孔复合结构的过程中,无杂质生成,氧化锌晶体结构也没有发生变化。多孔复合结构对模拟污染物的暗室催化降解研究结果显示,复合结构催化降解亚甲基蓝时起主要作用的是ZnO纳米棒,在多孔结构中受力变形产生电子空穴对,在无光条件下降解有机污染物,且孔径越大、水流冲击力越强,对亚甲基蓝的催化降解效果越好。     

化学气相沉积法制备纳微ZnO的实验和模拟研究进展

纳/微氧化锌材料性能优良,用途广泛,制备方法较多,其中化学气相沉积法(CVD)是较常用的方法之一。详细介绍了CVD方法制备纳米氧化锌的主要影响因素,概述了计算流体动力学(CFD)模拟在化学气相沉积法方面的应用和研究现状,并指出应该采用实验研究和计算模拟相结合的方法进行研究,利用计算模拟指导实验,从而实现纳微结构的可控生长。     

三维石墨烯/氧化锌纳米结构复合材料的制备及其在双氧水检测中的应用

通过化学气相沉积法制备出孔洞为300~500μm骨架完好的三维石墨烯,并采用晶种诱导法在三维石墨烯表面原位生长直径为100nm左右、长度达2.80μm的ZnO纳米棒,从而制备出高度结晶的三维石墨烯/氧化锌纳米结构的复合材料。复合材料用XRD、SEM进行表征,并通过循环伏安曲线(CV曲线)及时间电流曲线(I-t曲线)电化学测试方法,测试三维石墨烯/氧化锌纳米结构复合材料对双氧水的检测情况。结果显示,采用新方法制备的三维石墨烯/氧化锌纳米结构复合材料作为电极对双氧水表现出优异的检测性能,检测限为1μmol/L,且线性检测范围为10~120μmol/L。     

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.