MB8镁合金超疏水表面的制备和润湿性

通过激光加工在MB8镁合金表面构造具有规则结构的纹理,再制备1H,1H,2H,2H-全氟葵烷基三氯硅烷(FDTS)自组装分子膜,从而构建了MB8镁合金超疏水表面。用扫描电子显微镜和接触角测量仪观察和测量试样表面的形貌和润湿性。结果表明,激光加工在试样表面构造的粗糙结构和低表面能物质FDTS自组装分子膜使该试样具有超疏水性;经激光加工和沉积自组装分子膜后,MB8镁合金试样表面对水的接触角显著增大(达到150°以上)。将MB8镁合金超疏水表面加工成漂浮平台,承载能力的测试结果表明,超疏水平台的漂浮承载能力明显比非超疏水性平台的大,平台的承载能力与接触角的数值成正比。理论计算结果和"气垫"的存在表明,该超疏水表面符合Cassie-Baxter。状态模型,对接触角理论值与测量值的分析表明分级粗糙结构对超疏水表面构建有重要作用。     

TC4钛合金超亲/疏水TiO2膜制备及其摩擦性能分析

以TC4钛合金为基底,采用阳极氧化法在其表面制备TiO2膜,再用十七氟癸基三甲氧基硅烷修饰TiO2膜。利用OCA20视频光学接触角测量仪测得基底、TiO2膜、TiO2/氟硅烷复合膜表面对去离子水的静态接触角分别为62°、2°、158°,表面润湿性经历了由亲水到超亲水再到超疏水的转变。室温下,以球/平面接触方式,采用440-C不锈钢球为摩擦对偶件,利用UMT-2多功能微摩擦磨损试验机测试仪对试样进行摩擦磨损试验。结果表明,基底摩擦系数在0.4左右,TiO2膜和TiO2/氟硅烷复合膜摩擦系数在0.1左右,TiO2膜具有减摩特性;基底磨损表现为磨粒磨损,TiO2膜和TiO2/氟硅烷复合膜则表现为塑性变形及轻微的磨粒磨损。     

石墨烯/硬脂酸超疏水复合膜层的防腐性能

用溶液共混法制备石墨烯/硬脂酸(G/SA)共混溶液,再将其滴涂在微弧氧化后的AZ91镁合金表面制备出超疏水复合膜。用扫描电子显微镜、接触角测量仪和傅立叶红外光谱仪等手段表征了复合膜层的表面形貌、润湿性能以及化学组成,并对微弧氧化膜层和复合膜层进行了阻抗谱和极化测试。结果表明:石墨烯/硬脂酸共混溶液滴涂后使多孔的超亲水微弧氧化膜层转变为具有微/纳米结构的超疏水复合膜层,静态接触角达到162°;复合膜层的腐蚀电流密度降低了4个数量级,电荷转移电阻增加了4个数量级,且能对镁合金提供有效的腐蚀保护。     

具有不同黏附力Al-Mg-Si合金超疏水表面的制备与表征

基于位错刻蚀理论利用溶液浸泡处理A1-Mg-Si合金在其表面形成微观粗糙表面结构,采用自组装技术在此表面制备FDTS自组装分子膜.采用X射线衍射仪、扫描电子显微镜和表面粗糙度仪对试样表面形貌进行了表征;采用接触角测量仪对试样表面接触角进行了测量.结果表明,试样经溶液浸泡处理和沉积自组装分子膜后,其表面润湿性实现了由亲水到超亲水再到超疏水的转变;改变溶液浸泡时间得到具有不同微观结构的表面,沉积自组装分子膜后得到的超疏水表面具有不同的滚动接触角,其表面黏附力具有明显差异.分析认为,超疏水表面的获得是溶液浸泡处理得到的粗糙表面结构和低表面能物质FDTS自组装分子膜共同作用的结果;表面黏附力的差异是试样表面微观形貌的不同造成水滴在其表面所处状态的差异引发的.     

微弧氧化对镁合金摩擦及胶接性能的影响

为解决镁合金表面耐摩擦和胶接性能较差的问题,采用微弧氧化法在MB15镁合金原位生长微弧氧化膜层.利用X射线衍射、扫描电镜、摩擦磨损试验机和万能拉伸实验机对膜层的结构组成、表面形貌、摩擦性能和胶接性能进行了研究.结果表明：MB15镁合金表面微弧氧化后可以形成均匀多孔的陶瓷涂层,膜层由MgO和MgAl2O4组成,经微弧氧化...     

层层自组装SiO_2/木材复合材料的超疏水性及其形成机制

通过层层自组装技术制备纳米SiO_2薄膜,利用1H,1H,2H,2H-全氟辛基三乙氧基硅烷(POTS)作为疏水改性剂制备出了超疏水木材。EDXA、FT-IR、XRD、SEM分析证实经过层层自组装处理后,木材表面生长出了纳米SiO2薄膜,后续修饰处理的POTS试剂后与纳米SiO_2通过化学键结合生长于木材表面。接触角测试显示,当木材表面自组装5层后,制备的木材具有超疏水性能,接触角高达161°。TG分析表明超疏水木材具有较好的热稳定性。超疏水木材表面的形成机制可以归纳为层层自组装的纳米SiO_2薄膜在木材表面构建了微纳米级粗糙结构,并经后续低表面能物质POTS的修饰处理使得木材表面由亲水转变为超疏水。     

基于铸铝微弧氧化构筑超疏水表面及工艺优化

为了提高铸铝表面的防腐蚀和防污能力,通过微弧氧化在铸铝表面原位生长出均匀分布的氧化铝陶瓷膜层,采用长链氟硅烷对微弧氧化陶瓷膜层进行修饰,制备了接触角大于150°的超疏水表面。采用X射线衍射仪(XRD)、扫描电镜(SEM)研究了铸铝微弧氧化陶瓷膜结构和表面形貌,并测试了长链氟硅烷修饰对铸铝以及微弧氧化铸铝表面接触角的影响,探讨了铸铝微弧氧化陶瓷膜层的长烷链氟硅烷修饰机理。通过正交试验确定了正向电压为480 V,占空比为50/50,微弧氧化时间为15 min时,生成的微弧氧化陶瓷膜层具有较为连续和致密的微米级突起结构,经十三氟辛基三乙氧基硅烷修饰后获得接触角高达162.6°的超疏水表面,并且具有一定的持久性和稳定性。     

液晶聚芳酰胺自组装膜的摩擦学性能

研究了液晶聚芳酰胺在表面羟基化载玻片上的自组装行为及液晶聚合物薄膜的摩擦磨损性能。结果表明．自组装液晶聚芳酰胺薄膜修饰的基底在低载荷下与Si3N4陶瓷球对磨时的摩擦系数非常低和稳定，耐磨寿命较其它聚酰胺类固体润滑膜更长。因此，自组装液晶聚芳酰胺超薄膜可以作为低载荷下硅基材料的减摩抗磨防护层。     

表面润湿性对水润滑Al-Mg合金摩擦学特性的影响

通过自组装技术在Al-Mg合金表面制备自组装分子膜,采用接触角测量仪测定了自组装分子膜的水接触角,采用多功能摩擦磨损试验机对制备不同自组装分子膜的Al-Mg合金在3种润滑方式下进行摩擦磨损实验。结果表明,制备自组装分子膜可显著改变Al-Mg合金的表面润湿性,制备FDTS、FOTS、OTS自组装分子膜的表面呈疏水性,制备MPS、APS自组装分子膜的表面则呈亲水性,5种自组装分子膜接触角由大到小的顺序为FDTS>FOTS>OTS>MPS>APS。自组装分子膜的疏水性越强,Al-Mg合金的摩擦系数越小。同种自组装分子膜在干摩擦条件下摩擦系数最大,浸水润滑条件下摩擦系数有所下降,喷水润滑条件下摩擦系数最小。     

表面润湿性对水润滑Al-Mg合金摩擦学特性的影响

通过自组装技术在Al-Mg合金表面制备自组装分子膜,采用接触角测量仪测定了自组装分子膜的水接触角,采用多功能摩擦磨损试验机对制备不同自组装分子膜的Al-Mg合金在3种润滑方式下进行摩擦磨损实验。结果表明,制备自组装分子膜可显著改变Al-Mg合金的表面润湿性,制备FDTS、FOTS、OTS自组装分子膜的表面呈疏水性,制备MPS、APS自组装分子膜的表面则呈亲水性,5种自组装分子膜接触角由大到小的顺序为FDTS>FOTS>OTS>MPS>APS。自组装分子膜的疏水性越强,Al-Mg合金的摩擦系数越小。同种自组装分子膜在干摩擦条件下摩擦系数最大,浸水润滑条件下摩擦系数有所下降,喷水润滑条件下摩擦系数最小。     

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.