改性纳米TiO2/PTFE复合氟碳防污闪涂层的制备及其性能

为防止输电线路上污闪事故的发生,以氟碳树脂(FEVE)为成膜剂,以改性纳米TiO2和聚四氟乙烯(PTFE)微粉为复合填料,制备了一种新型的有自清洁效应的纳米TiO2/PTFE复合氟碳防污闪涂料.采用傅里叶变换红外光谱仪(FTIR)表征纳米TiO2改性前后的结构,通过扫描电镜(SEM)、X射线光电子能谱仪(XPS)、接触角测量仪对复合氟碳防污闪涂层表面的微观结构及疏水性进行了分析,对涂层表面的光催化自清洁性和疏水性保持机制进行了深入探讨.结果表明:改性纳米TiO2和PTFE通过化学键合作用在复合氟碳防污闪涂层表面构建了微纳复合粗糙结构,与水静态接触角达134°,涂层不仅具有优良的理化、电气绝缘性能,而且还具有有效的自清洁功能和疏水性保持性能.     

普鲁士蓝/氟化超支化聚氨酯复合涂层材料及其光热转换超疏水性能

首先制备氟化超支化聚氨酯(FHPU),然后与具有光热转化功能的普鲁士蓝(PB)纳米粒子复合,得到光热转换功能的PB/FHPU超疏水防结冰复合涂层材料。利用FTIR、TGA和DSC等测试分析了FHPU和PB/FHPU超疏水防结冰复合涂层材料的结构及性能,通过光热转换实验证明了复合涂层材料出色的光热性能;深入探究了PB纳米粒子的添加量对复合涂层材料表面性质和光热转化性能的影响。结果表明,当PB质量占FHPU的13%时,复合涂层材料可形成具有微纳结构的复合涂层,涂层表面最大接触角达157°,滚动角为1.8°。同时,该涂层在808 nm激光照射下10 s内温度可升高78.1℃,最高温度达到148.7℃。因而,光热转换功能性超疏水防结冰复合涂层材料具有良好的疏水、防结冰性能。      

超疏水复合涂层的制备和性能研究

采用大气等离子喷涂工艺(APS)制备了双层Al_2O_3/PTFE复合涂层和单层Al_2O_3-PTFE复合涂层两种涂层结构体系的疏水复合涂层,使用扫描电子显微镜(SEM)、3D表面形貌仪、显微硬度计、接触角测试仪和摩擦磨损试验机分别表征了复合涂层的微观形貌、相组成、粗糙度、硬度、疏水性能以及耐磨性能。评价复合涂层的性能并进而研究了Al_2O_3陶瓷作为粘结层和硬质颗粒填充相以及工艺参数对复合涂层的疏水性能和耐磨性能的影响。结果表明:无论Al_2O_3陶瓷作为粘结层还是硬质填充相添加到涂层中,都显著提高了单一PTFE涂层的摩擦学性能。Al_2O_3-PTFE复合涂层的耐磨性能优于Al_2O_3/PTFE复合涂层,两复合涂层的磨损率和摩擦系数依次为2.84×10~(-5)mm~3/N·m、9.97×10~(-5)mm~3/N·m和0.51、0.38;复合涂层的表面都具有良好的疏水性能,与水的静态接触角分别为155.4°和148.9°。良好的疏水性能源于表面粗糙的微纳米级突起结构和表面存在密集分布的低表面能氟化物的协同作用。进行摩擦磨损试验后表面的突起结构受到一定的破坏,涂层的疏水性能有所下降,但是Al_2O_3/PTFE复合涂层仍然具有超疏水性。     

蜡质超疏水涂层的制备及其防粘附应用

在棕榈蜡/乙酸乙酯悬浊液中超声分散疏水性纳米二氧化硅制备蜡质超疏水涂料,用浸渍提拉法在玻璃片表面制备超疏水涂层。单因素实验考察棕榈蜡在乙酸乙酯中的浓度、疏水性纳米二氧化硅的添加量和干燥方式对疏水性能的影响,分析不同因素情况下的接触角、滚动角和防粘附性能。结果表明棕榈蜡在乙酸乙酯中的浓度为4g/100mL,纳米二氧化硅添加量占棕榈蜡质量的1/2,室温中自然干燥,涂层疏水性效果最佳,此条件下制备的超疏水涂层的接触角为150.60°,滚动角为6°。该涂层适用于不同的基材(如玻璃片、PE膜、BOPP膜的铝塑复合膜)。通过对酸奶粘附性的试验,发现涂层在各种基材表面表现出良好的防粘附性能,酸奶可在其上自由滚动。用热封时间作为指标,测试施加涂层后的热封性能,结果表明,涂层的施加不影响铝塑复合膜等耐高温材料的热封性。     

聚苯酯/聚四氟乙烯复合涂层的制备及润湿性能

以聚苯酯和聚四氟乙烯粉末为原料,采用简单的一步成膜法分别制备了纯的聚苯酯(POB)、聚四氟乙烯(PTFE)涂层和聚苯酯/聚四氟乙烯复合涂层。接触角测量仪测量结果表明制备的聚苯酯、聚四氟乙烯涂层的接触角都大于130°,具有疏水性能;而聚苯酯/聚四氟乙烯复合涂层接触角都大于150°,具有超疏水性能。扫描电子显微镜测试表明聚苯酯和聚四氟乙烯共混后形成的复合涂层具有微纳米二元复合结构。X射线光电子能谱仪测试结果表明聚苯酯和聚四氟乙烯较好地共存于复合涂层表面,正是由于复合涂层表面的微观形貌和化学成分的共同作用,使其具有了超疏水的性能。文中考察了PTFE与POB质量比对复合涂层润湿性能的影响,结果表明随着PTFE与POB质量比的增加,复合涂层的水接触角先增大后减小,但都大于150°。而水滴的滚动角则呈现相反的变化规律。这种制备聚苯酯/聚四氟乙烯复合涂层的方法简单方便,不需要复杂的实验步骤和昂贵的实验设备,适合于大规模和工业化生产。     

PVDF/FEP/ZnO复合涂层的制备及防垢性能研究

为了解决金属表面的结垢问题,以聚偏氟乙烯（PVDF）和聚全氟乙丙烯（FEP）为原料,通过添加不同含量的纳米ZnO制备了PVDF/FEP/ZnO复合涂层,研究了纳米ZnO添加量对复合涂层疏水性能和防垢性能的影响。通过接触角测量仪、扫描电子显微镜（SEM）和X射线粉末衍射仪（XRD）对涂层进行了表征。结果表明：纳米ZnO的添加量为5.0%（质量分数）时,PVDF/FEP/ZnO复合涂层的表面自由能为8.6 mJ/m²,水接触角为114.8°;PVDF/FEP/ZnO复合涂层在过饱和碳酸钙溶液中结垢336 h后,其表面的碳酸钙结垢量仅为环氧涂层的72%,且文石和球霰石的摩尔分数之和达到了91.4%,表明复合涂层具有优良的防垢性能,在防垢领域具有较好的应用前景。     

TiO2纳米复合氟碳涂料的性能

为了提高氟碳涂料的性能,采用硅烷偶联剂KH-550对纳米TiO2进行表面改性,再添加于氟碳涂料制成TiO2纳米复合氟碳涂料,在马口铁上涂膜.采用红外光谱、透射电镜(TEM)及沉降试验对纳米TiO2的改性效果进行评价,通过自清洁测试、接触角测量仪、色差仪和电化学测量系统分别对未添加TiO2的氟碳涂料涂膜和TiO2纳米复合氟碳涂料涂膜的自清洁性能、疏水性能、抗紫外性能及耐腐蚀性能进行了表征.结果表明:改性后的纳米TiO2分散性好,制得的TiO2纳米复合涂料涂膜具有较好的自清洁、疏水、抗紫外老化、耐腐蚀等性能,比未添加TiO2的氟碳涂料涂膜的有较大改善;且添加纳米TiO2并未影响涂膜的硬度、附着力、耐冲击、耐水、耐酸碱等性能.     

TiO_2/含氢硅油超疏水防腐涂层的制备及其性能研究

用硬脂酸在TiO_2表面引入疏水性甲基,将改性后TiO_2与含氢硅油(PMHS)杂合,在铝基底上形成超疏水涂层。采用X射线衍射仪、红外光谱、扫描电镜和接触角分析仪,表征涂层的表面形貌和疏水性。结果表明:TiO_2/PMHS复合涂层表面具有微/纳米双重粗糙结构,与水的静态接触角为155°,滚动角8°;采用极化曲线等电化学法对涂层防腐性能进行表征,结果表明其腐蚀电位从裸铝片的-926mV正移至-603mV,腐蚀电流密度从裸铝片的4.68×10-5 A/cm~2下降至6.60×10~(-6)A/cm~2,显示出良好的防腐性能。     

CaCO3/SiO2复合粒子涂层的表面结构及其疏水性能研究

以机械高速搅拌法制备了具有草莓结构的CaCO₃/SiO₂复合粒子,并对其进行了表面修饰改性.利用聚硅氧烷的自组装功能,将制备的复合粒子与硅氧烷一起制备了具有“荷叶效应”的超疏水涂层,静态水接触角达169°,滚动角约为2°.通过扫描电镜观察涂层的表面微观形貌,发现该涂层具有微米-纳米相结合的双层粗糙结构.微米凸起的粒径在2～3μm左右,纳米凸起的粒径约为200nm左右,与荷叶具有类似的结构排布方式.通过原子力显微镜和接触角的测试,探讨了表面微观结构、涂层粗糙度和涂层疏水性能之间的关系.结果表明：复合粒子构成的非均相界面的水接触角符合Cassie模型.复合粒子赋予涂层的双微观粗糙结构与自组装成膜硅氧烷的低表面能的协同效应,使涂层具有了优良的超疏水性能.     

碱式硫酸镁晶须复合SiO2纳米粒子制备高/低黏附性超疏水涂层

超疏水材料因性能独特,应用前景广阔而被广泛关注。本文采用碱式硫酸镁晶须(MOSWs)与二氧化硅纳米粒子制备超疏水涂层,首先对MOSWs及50 nm、500 nm SiO₂进行表面改性以降低表面能,然后基于混料实验将三者按比例混合以构造表面粗糙度,以接触角、滚动角及平均粗糙度R_a为响应变量建立回归模型,分析了混合分量的形貌、尺寸与混合比例对响应变量的影响,并探讨了超疏水涂层微观结构对水滴黏附性的影响以及粗糙度与超疏水性能之间的关系。结果表明：MOSWs复合SiO₂纳米粒子可制备具有不同黏附性的超疏水涂层,单独使用MOSWs可制备高黏附性超疏水涂层,其接触角达152.59°,涂层水平倒置水滴不滴落;而MOSWs与50 nm SiO₂以相同质量分数混合,可制备低黏附性超疏水涂层,其接触角达163.25°,滚动角可趋近0°。所制备涂层的平均粗糙度R_a值位于5～10μm之间时,接触角较大,滚动角较小,超疏水性能较佳。     

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.……     

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.     

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.     

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 ...