喷砂-阳极氧化法构建分形超疏水Ti6Al4V表面及性能研究

主要采用喷砂-阳极氧化法在Ti6Al4V钛合金表面构建微纳二级复合结构,使用低表面能物质FAS-17(十七氟硅烷)修饰后可获得超疏水表面。结果显示,喷砂形成的微米级凸台与阳极氧化形成的纳米管复合结构表面的液滴接触角达到了159.8°。在空气中放置30d后,仍然具有优异的超疏水性能,并具有一定的耐盐水性能。     

铝基表面超疏水材料的制备工艺、效果及耐蚀性

超疏水表面在自清洁材料、腐蚀防护及微流体运输等领域有着广阔的应用前景,目前对金属超疏水表面的研究较少,且制备方法较复杂,不能大面积制备。分别采用喷砂、阳极氧化、喷砂-阳极氧化等方法在铝基体表面构造粗糙结构并对其进行修饰,制备了超疏水表面,通过SEM、接触角及滚动角测定、腐蚀速率测定等分析了超疏水表面的微观形貌、疏水性能和耐海水腐蚀性能。结果表明:喷砂-阳极氧化法制备的铝金属表面具有微米-纳米二级结构,经氟化处理后,与水的接触角达158°,滚动角为1.5°,疏水性能良好;超疏水表面材料的腐蚀速率比铝材低1个数量级。     

阳极氧化法构建纳米结构制备铝超疏水表面

研究了喷砂和阳极氧化技术相结合,在铝合金表面构建合适的微米一纳米二级结构,并通过氟硅烷的修饰降低表面自由能,以制备铝基超疏水表面材料。研究表明：不同的电解液进行阳极氧化制得的样品氟化后具有不同的接触角。SEM分析可知,山峰山谷状的微米级结构和蜂窝状的纳米级结构形成的二级结构是提高疏水性能的关键。当接触水滴时,这种二级结构可以稳定地捕获空气,产生超疏水性。     

SiC/Al复合材料超疏水表面的制备

采用化学刻蚀法在SiC/Al复合材料表面构筑微纳结构,通过SEM和表面接触角测量仪分析刻蚀表面的微观形貌特征及润湿特性,并探讨了其与刻蚀时间之间的关系;借助热震试验评价SiC/Al复合材料超疏水表面的温度骤变耐受特性。结果表明:弥散分布的微米级SiC颗粒的存在使得刻蚀后的SiC/Al复合材料表面易形成由微米级粒状结构和纳米级凹坑结构复合而成的微观结构;氟硅烷修饰后的蚀刻表面的接触角最高达到166.8°,滚动角最低为3°,具有很好的超疏水特性;SiC/Al基超疏水表面具有较好的耐受温度骤变特性。     

棉织物表面的超疏水功能改性整理与性能表征

采用新的方法制备超疏水棉织物,突破了传统使用额外纳米粒子构造粗糙表面结构制备超疏水纺织品的局限性。首先采用有机硅树脂在织物表面形成一层疏水性薄膜,然后借助硅树脂的黏附性将十八胺牢固地固着在织物表面,以此达到构造粗糙表面结构和降低织物表面能的目的。实验结果表明,整理后的棉织物与水的接触角高达154.4°±0.6°,经、纬向强力分别下降了6.2%和8.3%,而白度增加了1.3%。棉织物表面经过30次机械摩擦后,其接触角为151.5°±0.4°。最后对改性前后棉织物的表面形貌和超疏水机理进行了深入分析。     

旱金莲叶、花表面的超疏水性研究

早金莲的叶、花表面有很好的超疏水性,水滴在其表面的静态接触角为150°、145°,滚动角分别约为5°、10°,通过扫描电镜观察发现,在其叶、花的表面分布有大量呈规则排列的微纳米级复合“花簇”、“凹槽”.微纳米复合结构使其表面有良好的超疏水性,雨后,能保持“滴水不沾”、“一尘不染”.采用Cassie理论对其表面的超疏水性...     

微纳分级结构ZnO-氟碳树脂超疏水表面的制备研究

超疏水表面具有特殊的微纳分级结构和自清洁、防污染等优异性能,国内外对其有着广泛的研究和应用。利用硝酸锌和氢氧化钾共沉淀的方法制备出海胆型微-纳分级结构的氧化锌(ZnO)粒子,然后用氟碳树脂衍生物对其进行疏水化接枝改性,最终制备了超疏水表面。利用X射线衍射仪对制备的产物进行物相分析,利用扫描电镜和动/静态接触角分析仪表征ZnO的微观形貌及疏水表面的接触角。结果表明,微纳分级结构的ZnO粒子经氟碳树脂改性后具有优异的疏水性能,所制备的疏水表面的水静态接触角能够达到(156±1)°,接触角滞后低至3°。该方法简单易行,适合工业化生产。     

铝基超疏水表面的耐海水腐蚀性能研究

研究了喷砂和阳极氧化技术相结合,在铝合金表面构建合适的微米/纳米二级结构,并通过氟硅烷的修饰降低表面自由能,以制备铝基超疏水表面材料,并对表面的耐海水腐蚀性能进行了研究,研究表明,当采用100g/L硫酸、10g/L草酸、10g/L丙三醇作为电解液进行阳极氧化,孔洞孔径达200nm时,接触角达157°。模拟人工海水中的腐蚀实验,结果表明,超疏水表面材料的腐蚀速率比未经处理的空白试样缓慢一个数量级。     

超双疏耐磨PPS基涂层的制备与性能

以NH_4HCO_3为造孔剂,碳纳米管(CNTs)为纳米级纤维填料,采用简单的喷涂工艺制备出超双疏耐磨聚苯硫醚(PPS)基涂层。采用扫描电镜(SEM)、接触角测量仪分析涂层的表面形貌和疏水、疏油性能。采用定载砂纸打磨法测试双疏涂层的耐磨损性能。结果表明:造孔后的涂层表面粗糙,表面的多孔结构和CNTs构成了特殊的微纳二元复合网络结构。当NH_4HCO_3的含量为5%(质量分数)时,涂层实现超疏水和超疏油,对水、甘油和乙二醇的接触角分别为162°,158°和152°。用砂纸反复打磨10000次后,涂层表面轻微磨损,仍保持了高疏水效果,具有良好的耐磨性能。     

PVDF/SiO2/PDMS涂层超疏水纺织品性能

目的 针对普通纺织品材料防水性和防污性较差的问题,制备具有自清洁功能的超疏水涂层纺织品,并研究其性能.方法 以涤纶织物为基材,通过非溶剂诱导相分离法,使用聚偏氟乙烯和疏水纳米二氧化硅复合液在纺织品表面构筑微纳粗糙结构,采用聚二甲基硅氧烷对其进行疏水化处理,获得自清洁超疏水涂层纺织品.采用扫描电子显微镜、X射线能量散射光谱和视频光学接触角测量仪等对其结构和性能进行表征,并通过机械摩擦、洗涤、酸/碱/盐溶液浸渍和紫外光照等方法对其表面超疏水稳定性进行考察.结果 当聚偏氟乙烯质量分数为2％,疏水纳米二氧化硅质量分数为0.4％,聚二甲基硅氧烷质量分数为1％时,制备的纺织品的表面接触角可达(162.2°±0.8°),滚动角达(2.0°±0.4°),具有优异的超疏水自清洁效应;经72 h酸/碱/盐溶液浸渍、196 h紫外光照、2500次摩擦和120次家庭水洗后,其表面接触角仍大于150°,表现出优异的超疏水稳定性.结论 采用简便的非溶剂相分离法制备的涂层纺织品具有优异的自清洁性能,并且其超疏水性能具有机械耐久性和化学稳定性,有望应用于纺织材料包装领域.     

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.……     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

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.……     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

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 ...