Zn-PTFE复合电极的电沉积过程及析氢性能

研究了Zn PTFE(聚四氟乙烯 )复合电极的电沉积过程 ,考察了它在碱性介质中的析氢性能 ,讨论了镀液中PTFE悬浮量、阴极电流密度、电沉积电量及温度对镀层中PTFE含量的影响。结果表明 :控制镀液中PTFE悬浮量为 30ml·L-1 ,镀液温度 2 5℃ ,以 5.0A·dm-2 电流密度电沉积 2 2 .5C ,可制备出PTFE微粒分散均匀的复合电极 ;复合电极与Zn电极相比有更高的析氢过电位 ,这是由于PTFE的憎水性所致。     

镧-钼合金电镀及其析氢电催化性能

用正交试验法研究了钛基上La-Mo合金电镀方法及其工艺条件。经测试，合金镀层结合力强、硬度高、耐腐蚀及耐热性能优良。以钛基电镀La-Mo合金镀层作为阴极，在300g／L NaCl溶液中，在60℃，电流密度为300mA／cm^2下电解，能降低氢超电势680mV，显示了钛基电镀La-Mo合金镀层优良的析氢电催化性能。     

Ti/Pb-WC复合镀电流密度对镀层性能的影响

为了寻找理想的电催化电极及减少制备工序,采用复合电沉积方法在钛基材上制备了Pb-WC镀层.采用SEM、电化学测试等对纯铅层及Pb-WC镀层的表面形貌、元素组成及电化学性能进行了对比研究,分析了电流密度对沉积速率以及镀液中WC浓度对镀层中WC含量的影响.结果表明:电流密度为4 A/dm2,镀液中WC的浓度为30 g/L时...     

多孔Ni-WC复合电极的制备及其在酸性溶液中的电催化析氢性能

目前,关于多孔Ni-WC电极的电催化析氢(HER)性能的报道较少。以多孔海绵镍为基体,采用复合电沉积制备多孔Ni-(WC)x复合电极。运用扫描电镜(SEM)和X射仪线衍射仪(XRD)表征电极的表面形貌和微观结构,通过阴极极化、电化学阻抗(EIS)、循环伏安、计时电流法研究多孔Ni-(WC)x电极在0.5 mol/L H2SO4溶液中的电催化析氢性能。结果表明:与多孔基体Ni电极相比,多孔Ni-(WC)x电极具有较低的析氢过电位、较低的电化学反应阻抗、较小的表观活化能以及较大的交换电流密度;随着镀液中WC浓度的升高,所制备的多孔Ni-(WC)x电极的电催化析氢活性增强,其中Ni-(WC)40电极的表观交换电流密度是多孔Ni基体电极的966.7倍,其表观活化能为5.95 kJ/mol,并具有较好的耐蚀性和析氢稳定性。     

钛基Co中间层SnO2电催化电极的制备及性能研究

为提高钛基二氧化锡电极的稳定性,设计并制备了含Co中间层的钛基二氧化锡电催化电极Ti/Co/SnO2,以苯酚为目标有机物,考察了所制备Ti/Co/SnO2电极电催化氧化降解苯酚的性能,并采用SEM、EDX以及XPS等检测方法分析了Ti/Co/SnO2电极表面的形貌、元素组成及元素化学态.研究结果表明,含有中间层的Ti/Co/SnO2电极其使用寿命较不含中间层的钛基二氧化锡电极Ti/SnO2大幅度提高,但其对苯酚的电催化降解活性有所下降,氧化还原电对Co2 /Co3 的存在是所制备Ti/Co/SnO2电极稳定性及电催化活性改变的主要原因.     

碱性和酸性体系对电沉积Pb-PANI-WC复合镀层性能的影响

为了寻找理想的电极材料,简化制备工序,采用2种不同组成的镀液(碱性、酸性),利用复合电沉积的方法在钛基材上制备出一种新型的Pb-PANI-WC复合镀层;分析了2种镀液体系对Pb-PANI-WC复合镀层的电化学性能、外观形貌、相组成的影响,并与铅银合金镀层和碱性体系纯铅镀层进行了比较。通过电化学性能测试结果对比可知:2种Pb-PANI-WC复合镀层的电化学性能均优于铅银合金和碱性纯铅镀层;与碱性纯铅镀层相比,复合电沉积制备的复合镀层具有较好的电催化活性、耐蚀性,较高的腐蚀电位和较低的腐蚀电流密度,加速试验寿命更长,并且碱性镀液制备的复合镀层性能最佳。     

稀土铒改性钛基PbO2电极的制备和性能

采用电沉积法制备了稀土铒改性钛基PbO₂电极,用SEM、EDS和XRD技术分析了表面物相和结构,用EIS、线性极化扫描、荧光光谱分析和苯酚降解实验对其性能进行了表征。结果表明,稀土铒改性钛基PbO₂电极镀层的结构主要为β-PbO₂晶型,其晶粒明显细化,比表面积增大;电致生成羟基自由基的能力是未改性电极的2.3倍;改性电极具有更小的电化学反应电阻和更高的阳极析氧过电位。苯酚降解实验表明,稀土铒掺杂改性明显提高了钛基PbO₂电极的电催化性能,2h降解率达91.8%。     

电沉积制备Ni-S涂层电极的研究

以泡沫镍为基体电沉积制备了Ni-S涂层电极.通过对电流密度、电沉积温度、电沉积时间和镀液pH值等条件对涂层析氢性能影响的研究,确定了适宜的电沉积工艺条件;电极涂层的XRD、SEM测试结果表明涂层为非晶态结构、表面颗粒大小均匀且具较大表面积;电解过程中出现了Ni3S2由非晶态向晶态的转变,由于Ni3S2具有较强的吸附氢能力,是析氢反应的催化活性中心,电解过程中Ni3S2的出现降低了电极的析氢电位.模拟电解水实验结果表明泡沫镍基Ni-S涂层电极较Raney-Ni电极具有更好的析氢活性.     

改性PbO2 电极电催化降解水中硝基苯酚

为研究PbO2电极的性能,在酸性溶液中,以电沉积法制备了改性钛基PbO2电极,优化并确定了电极的制备工艺,并利用SEM对电极的表面形貌进行了检测.以硝基苯酚为目标有机物,考察了电极的电催化氧化性能.采用铋掺杂PbO2电极处理水中邻硝基苯酚、间硝基苯酚和对硝基苯酚,并对不同硝基苯酚的矿化过程以及降解动力学进行了比较.研究表明:改性PbO2电极的电催化性能优于传统的PbO2电极;邻硝基苯酚在本研究条件下更易被降解.     

表层稀土掺杂PbO_2电极及对苯酚电催化氧化性能研究

以钛电极为基体,用热分解法制备Sn-Sb中间层,电沉积方法制备稀土La掺杂PbO2电极,优化了制备改性PbO2电极的电沉积温度、电沉积时间及稀土掺杂量。以苯酚废水为目标有机物,借助于苯酚去除情况分析电极的电催化氧化能力;分析了电极结构与电催化特性之间的关系。采用SEM、EDX和XRD分析了制备电极的表面形貌、元素组成、晶体结构。实验结果表明:电沉积液温度50℃,电沉积2 h,稀土镧掺杂量4∶1的PbO2电极降解苯酚电催化性能有明显改善,其去除率达到90.9%。     

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.     

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...     

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 ...