非晶态Ni-S-Co合金的制备和电化学性能

用电沉积方法制备非晶态Ni-S-Co合金镀层,研究了镀层的电化学性能.结果表明,与非晶态Ni-S合金相比,Co的引入可提高镀层中S的含量.在析氢反应中非晶态Ni-S-Co合金电极具有很高的电化学活性,电流密度为150 mA·cm-2时其析氢过电位仅为70 mV,比非晶态Ni-S合金低20 mV.在长时间电解过程中S发生溶出反应有助于提高电极的表面粗糙程度,是提高电极析氢活性的重要原因之一.在析氢过程中,非晶态Ni-S-Co合金电极吸附大量的H原子,使反应的活化能降低,这是其析氢活性高的主要原因.非晶态Ni-S-Co合金镀层的析氢机理为电化学脱附机理,即-快速的Volmer反应(电化学步骤)和一较慢的Heyrovsky反应(电化学脱附步骤).     

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.     

Electrochemical properties of amorphous Ni-S-Co alloy in alkaline medium

用电沉积方法制备非晶态Ni-S-Co合金镀层, 研究了镀层的电化学性能. 结果表明,与非晶态Ni--S合金相比, Co的引入可提高镀层中S的含量.在析氢反应中非晶态Ni--S--Co合金电极具有很高的电化学活性,电流密度为150 mA×cm-2时其析氢过电位仅为70 mV,比非晶态Ni-S合金低20 mV.在长时间电解过程中S发生溶出反应有助于提高电极的表面粗糙程度, 是提高电极析氢活性的重要原因之一. 在析氢过程中,非晶态Ni--S--Co合金电极吸附大量的H原子, 使反应的活化能降低,这是其析氢活性高的主要原因. 非晶态Ni--S--Co合金镀层的析氢机理为电化学脱附机理,即一快速的Volmer反应(电化学步骤)和一较慢的Heyrovsky反应(电化学脱附步骤).     

AC/Ni-Co复合电极材料的制备及其催化析氢性能

采用复合电沉积法制备了AC(活性炭) / Ni-Co 复合电极。XRD 和SEM 测试结果表明, AC 微粒的复合未改变Ni-Co 合金电极的物相结构, 但使镀层的表面粗糙度和真实表面积增大。通过稳态阴极极化曲线和电化学交流阻抗技术考察了不同电极在1 mol·L-1 NaOH 溶液中的催化析氢性能, 结果表明, 镀液中AC 含量为3 g·L-1时所制备的AC/ Ni-Co 复合电极较Ni 电极和Ni-Co 合金电极具有更高的催化析氢活性, 电流密度为30 mA·cm-2时, 析氢反应极化电位分别比Ni 电极和Ni-Co 合金电极正移230 mV 和140 mV , 表观交换电流密度分别是Ni 电极和Ni-Co 合金电极的42 倍和9 倍, 复合电极催化析氢性能的提高主要归因于电极真实表面积的增大。      

电沉积非晶Ni-Fe-P涂层析氢催化性能研究

采用直流电镀技术,通过改变电沉积电流密度制备了不同的非晶Ni-Fe-P涂层。采用稳态极化技术比较不同电流密度下电镀Ni-Fe-P合金涂层电化学催化析氢活性,发现电流密度200A/m2电沉积的Ni-Fe-P合金涂层的电化学催化析氢性能最好。通过XRD分析镀层相结构,SEM观察涂层表面的微观结构及EDX分析表面成分,研究影响非晶Ni-Fe-P合金涂层的析氢电催化活性原因。结果表明,影响非晶Ni-Fe-P合金涂层电催化活性的主要因素是镀层中Fe、P元素含量。当Fe的含量最大18.63%(原子分数),P的含量最小13.14%(原子分数)时,非晶Ni-Fe-P涂层电催化析氢活性最好。2     

复合电沉积制备（Ni-Mo）-TiO2电极及其电催化析氢性能

为开发新型廉价高效的析氢材料,用恒电流复合电沉积方法制备了(Ni-Mo)-TiO2复合电极,讨论了TiO2悬浮量和电沉积时间对电极催化析氢性能的影响.用XRD和SEM对电极的晶体结构和表面形貌进行了表征,以稳态极化曲线对电极的催化析氢特性进行了评价.结果表明,(Ni-Mo)-TiO2电极是纳米TiO2粒子相和纳米晶Ni-Mo固溶体相构成的复合电极.电极具有较高的催化析氢活性.在25℃、0.5mol.dm-3H2SO4溶液中其表观交换电流密度是Ni-Mo合金电极的2.6倍,是Ni电极的60倍.在电流密度为100mA·cm-2时,电极电势相对于Ni-Mo电极正移了120mV,相对于Ni电极正移了542mV.催化活性的提高源于反应机理的改变,表观活化吉布斯自由能相对于Ni-Mo合金电极降低了24.48kJ·mol-1.     

泡沫镍基镍硫合金涂层形貌、结构和析氢性能研究

在含有柠檬酸、硫脲和少许糖精的Watt镀液中,用电沉积的方法在镍泡沫基体上制备了镍硫合金涂层.各层涂层的形貌用SEM分析,各层硫量的分布用EDX测量.第1层涂层的结构用XRD测定.对各种电极包括镍泡沫基、镍网基上镍硫涂层电极,空白镍泡沫、镍网电极等的极氢电位进行了测量,研究了不同温度下镍泡沫基镍硫涂层电极的析氢活性.结果表明,镍泡沫基Ni-S涂层电极的析氢活性比镍网基Ni-S涂层电极活性高得多.镍泡沫各层硫量呈梯度的分布规律,由表及里硫含量逐步降低,中心层硫含量最低.各层表面微细颗粒大小及其均一性不相同,第1层的颗粒尺寸大于其它层的颗粒,其大小均一性也较其它层差.镍硫涂层是镍和Ni3S2组成的非晶态,使涂层具有丰富的表面积和氢气析出反应的活性中心.在加热的电解液中,在60℃以下和60℃以上的温区内电极析氢反应的机制不完全一样,受温度影响的程度也不一样.4000A/m2、90℃时,这种电极的析氢电位比15℃时析氢电位低180mV.     

离子液体中电沉积钴铬合金析氢性能研究

为了研究电沉积合金材料的析氢性能,本文在离子液体中通过脉冲电沉积法在碳钢上制备钴铬合金,研究了离子液体中电沉积不同的钴盐浓度对析氢过电位的影响,并与离子液体中电沉积的Co电极和Cr电极,水溶液中电沉积的Co-Cr合金电极进行了对比分析。利用三电极体系测试沉积电极在碱性环境下的电化学性能,采用线性极化法、方波电位法、交流阻抗法、恒电流电解法等电化学测试方法,并结合XRD、SEM、EDS进行了形貌、物相与元素分析。实验结果表明：制备的Co-Cr合金是多晶的,其晶粒尺寸为12.3 nm;当电流密度为10和100 mA/cm²时,所对应的析氢过电位分别为-105和-408 mV;当塔菲尔斜率为-0.228 V/dec时,析氢电阻为2.45Ω,计算得到其微观表面积为647 cm²;合金中Cr的质量分数约为8.5%,Co的质量分数约78.5%。随着钴盐浓度的上升,电沉积的钴铬合金电极的析氢性能越来越好。在离子液体中,通过脉冲电沉积制备的Co-Cr合金电极具有出色的电化学析氢性能,析氢机理为析氢反应动力学中的Volmer-Heyrovsky反应机理,析氢性...     

氯化胆碱-尿素体系中电沉积Ni-Fe-Sm析氢催化电极研究

采用恒电位电沉积技术,在氯化胆碱-尿素体系中制备Ni-Fe-Sm/Cu稀土合金电极并研究其析氢(HER)性能。通过阴极极化曲线(LSV)、循环伏安曲线(CV)等电化学测试方法及SEM等表征技术,研究沉积条件对稀土合金电极的析氢性能及其表面形貌的影响。结果表明,添加稀土元素Sm能够有效提升合金电极的析氢性能。在-1.22 V的沉积电位下,沉积20 min制备的Ni-Fe-Sm/Cu稀土合金电极析氢性能最佳。在10 mA/cm²电流密度下,稀土合金电极的析氢过电位仅115 mV,Tafel斜率最小,析氢反应受Volmer-Heyrovsky反应控制。且该条件下制备的Ni-Fe-Sm/Cu稀土合金具备最高的双电层电容,电催化活性表面积最大。通过交流阻抗法(EIS)可知,Ni-Fe-Sm/Cu合金电极具有较高电荷转移速率。此外,Ni-Fe-Sm/Cu稀土合金电极在碱性介质中具有较好的稳定性,在经过1000圈的循环侧安测试,电催化析氢性能没有明显变化。     

非晶态Fe-Mo合金在碱性溶液中的电催化析氢活性

研究了电沉积制备的非晶态Fe-Mo合金(组成分别为Fe82Mo18、Fe74Mo26和Fe71Mo29)电极在30％KOH溶液中，303～343K的温度范围内的析氢催化性能。三种非晶态合金都显示出较好的催化析氢活性。温度为343K，析H2电流密度为300nA／cm^2时的析H2过电位为150～157mV。非晶态Fe82Mol8、Fe74Mo26和Fe71Mo29合金上析H2反应的表观活化能分别为57．18，47．33，102．28kJ／mol。     

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