仿生超疏水二氧化硅/聚氨酯复合涂层的制备及性能

以纳米二氧化硅(SiO2)和不同有机硅含量改性的聚氨酯(PU)为原料,以乙酸乙酯为分散剂,采用简单的喷涂工艺,通过仿生的方法制备出与荷叶表面结构相似的SiO2/PU微-纳米复合涂层。用扫描电镜(SEM)对涂层表面进行了表征,研究了SiO2与PU的质量比以及有机硅含量对涂层表面结构及接触角的影响,并考察了涂层结构的稳定性,分析了涂层的形成机理和结构特点。结果表明,涂层表面具有与荷叶表面相似的微-纳米结构,SiO2与PU的质量比在4∶5至3∶5之间,有机硅质量分数大于15%时,涂层的水接触角为158°,滚动角为3°,具有超疏水特性,并且结构稳定,测试胶带剥离6次后,涂层仍具有超疏水特性。     

SiO_2-PTFE超疏水复合涂层的制备与分析

使用溶胶-凝胶法制备粒径均匀(250nm)、单分散性良好的纳米SiO2微粒,通过控制质量分数配比,将其水溶液与PTFE乳液混合成杂化乳液,后用旋涂法旋涂成膜,在380℃下进行热处理,得到表面形貌与荷叶相似微纳双层结构复合涂层。实验结果表明,用氟硅烷修饰表面后,涂层最高接触角达150.9°,滚动角为8°,具有较好的超疏水性能,且实验制作过程简单,成本低廉,具有一定的实用性。     

聚合物/疏水性SiO2超疏水复合涂层的制备及表征

使用低密度聚乙烯、聚甲基丙烯酸甲酯和疏水性SiO2为原料,通过简单的共混涂膜方法在玻璃基底上制得了具有超疏水性能的聚乙烯/疏水性SiO2和聚甲基丙烯酸甲酯/疏水性SiO2复合涂层;用接触角测量仪、扫描电子显微镜、X-射线光电子能谱仪等分析手段对涂层的润湿性能、微观结构以及表面化学成分等进行了表征。结果表明,所制备的两种聚合物/疏水性SiO2复合涂层的静态水接触角都超过150°,滚动角低至3.0°。聚合物和疏水性SiO2共混涂膜后形成了类似于荷叶的微纳米二元结构,是其表面具有优异超疏水性能的主要原因。     

单分散纳米SiO_2微球表面化学修饰及STF效应研究进展

溶胶-凝胶法制备纳米SiO2的分散性好、粒径可控,但由于纳米颗粒的比表面积大,容易团聚。因此可以通过化学方法对其进行表面化学修饰以改善其分散性,提高应用领域。本文主要介绍了溶胶-凝胶法制备单分散纳米SiO2微球,表面化学修饰的化学方法及剪切增稠(STF)效应研究进展。     

纳米SiO2层层组装构建超疏水表面

采用500nm和20nm的SiO2粒子,通过表面改性使其分别具有氨基和环氧基,利用氨基和环氧基的反应使500nm和20nm的SiO2粒子形成复合粒子,制备了具有微纳米双尺寸粗糙度的超疏水表面。通过扫描电镜和接触角测量仪对超疏水表面的结构及性能进行了表征,发现其具有微纳米二级结构,测得其静态接触角达到156°,滚动角小于3°,并且能够承受240℃的高温而保持其超疏水性能,为超疏水表面的制备提供了一种新的方法。     

纳米SiO_2/改性丙烯酸树脂低表面能防污涂料

低表面能防污涂料是船舶涂料的一个重要分支。利用有机硅改性的丙烯酸树脂作为成膜物质,纳米SiO2为填料,制备了低表面能纳米复合防污涂料。考察了有机硅单体对改性丙烯酸树脂性能的影响,发现随着有机硅含量的增加,改性后的树脂粘度减小,水接触角增加。研究了氟硅烷改性纳米SiO2含量对涂层形貌和水接触角的影响。结果表明,添加少量的氟硅烷处理的纳米SiO2(1%和3%)可显著增大涂层的水接触角,提高涂层的防污性能。添加纳米SiO2浆的涂层的水接触角要高于添加接枝氟硅烷纳米SiO2的涂层,而后者要高于添加未接枝氟硅烷纳米SiO2的涂层。当纳米SiO2的添加量在1%和3%时,涂层的水接触角分别达到101.8°和103°。采用纳米浓缩浆工艺分散后的纳米SiO2可以使涂层的表面形成微米-纳米的特征形貌,从而实现防污的目的。     

纳米微结构涂层的制备及其超疏水性研究

通过简便的纳米粒子填充法制备超疏水表面,将SiO2纳米粒子与含氟丙烯酸酯聚合物按不同比例混溶制备出具有不同微结构的表面,并探讨了表面微结构对润湿性能的影响.接触角测试表明,随着SiO2纳米粒子含量的增加,涂层与水接触角逐渐增大,并且当SiO2与聚合物质量比＞1.2时发生突跃,显示出超疏水性质.采用X射线光电子能谱分析了涂层表面化学环境,通过扫描电子显微镜、原子力显微镜、孔结构分析等方法观察和分析了不同SiO2纳米粒子含量时涂层表面微结构.研究结果表明,涂层表面润湿特性的变化主要归因于其表面微结构的不同.并通过粗糙表面润湿理论的Wenzel模型和Cassie模型解释了表面微结构对润湿性的影响及接触角的突跃现象.     

MWCNTs改性复合超疏水涂层及其耐化学性能

以低表面能聚甲基苯基硅氧烷共聚改性的环氧树脂为基体,纳米SiO2和多壁碳纳米管(MWCNTs)为填料,制备了具有耐化学介质特性的复合超疏水涂层。研究表明,有机硅共聚改性环氧树脂基体接触角为101°,具有良好的附着力和较高的硬度;复合涂层具有明显的类荷叶表面微-纳米二级结构;当MWCNTs的含量为3wt%时,涂层的接触角可达154°,滚动角为5°;在80℃下,2500ppm的含硼水溶液中浸泡15h后,未经MWCNTs改性涂层的接触角降至143°,失去了超疏水性能,50h后,降至98°,基本失去了疏水性。经MWCNTs改性后的EPPM3涂层,浸泡15h后,仍保留完好的二级微-纳米结构,接触角仍高达151°;浸泡50h后,接触角降至132°,仍具有较高的疏水性。     

超疏水低发射率PDMS改性环氧树脂/Al复合涂层的制备及性能表征

以片状Al粉为功能颜料，纳米SiO₂为微纳结构改性剂，聚二甲基硅氧烷(PDMS)改性环氧树脂(HYSZ)为黏合剂，采用简单的玻璃棒刮涂法制备了一种同时具有超疏水和低红外发射率性能的复合涂层。探讨了PDMS和HYSZ质量比、总填料添加量及片状Al粉和纳米SiO₂质量比对涂层性能的影响规律。结果表明：PDMS和HYSZ质量比对涂层附着力和疏水性能具有重要影响，当质量比为1∶9时，涂层具备良好的疏水性能，其附着力可达1级。总填料添加量对涂层性能影响明显，随着总填料添加量的增加，涂层发射率和光泽度可明显降低。当总填料添加量为50%时，涂层表面可产生明显的乳突状微纳粗糙结构，从而可明显提升涂层的疏水性能。片状Al粉和纳米SiO₂质量比会明显影响涂层的发射率和疏水性能，当质量比为5∶5时，涂层可具备良好的综合性能。此时涂层发射率可低至0.652,光泽度和附着力分别为2.7和1级，水接触角和滚动角分别为152°和8°。通过适当降低涂层表面能及在涂层表面构筑微纳粗糙结构可实现涂层超疏水、低发射率和高附着力的兼容。     

纳米SiO_2/有机硅改性聚丙烯酸酯复合材料性能研究

采用无皂乳液聚合技术和溶胶-凝胶技术,合成了纳米SiO2/有机硅改性聚丙烯酸酯无皂乳液,采用TEM和SEM观察了乳液和膜的微观结构。纳米复合无皂乳液具有优良的耐化学稳定性,随着纳米SiO2含量增加,乳液的离心稳定性降低;纳米SiO2/有机硅改性聚丙烯酸酯杂化膜的耐溶剂性显著好于有机硅改性聚丙烯酸酯膜,且随着纳米SiO2含量增加,杂化膜的耐溶剂性增加;杂化膜的透光性能好,且具有紫外光吸收特性;杂化膜含有的SiO2粒子的尺寸100nm,且均匀分散于聚丙烯酸酯组分中。     

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