氧化钴/氮掺杂介孔碳球的制备及其电化学性能研究

使用N-乙酰-D-氨基葡萄糖作为碳源,F127作为软模板,乙酸钴作为钴源和催化剂,在水热和高温热解条件下制得了具有较大的比表面积与丰富的介孔尺寸的孔道结构、尺寸为200~500nm的氧化钴/氮掺杂复合介孔碳球。该复合介孔碳球用作电极材料进行电化学测试,在2A/g的电流密度下电容值达到248.75F/g,经过1 000次循环寿命测试后其比电容值还能保留93%,显示出较高的比电容值和较好的循环稳定性,有望在能源存储、催化、吸附等领域得到应用。     

稻壳基介孔炭的制备及其在超级电容器中的应用(英文)

以量大价廉的稻壳为原料,先后经Na OH脱硅处理、预氧化、磷酸活化,在无模板的情况下制备出介孔炭材料。Na OH脱硅处理可有效除去稻壳中的硅并破坏纤维素的晶体结构,脱硅过程中形成的孔隙亦有利于高比表面积和高中孔率介孔炭的制备。所制介孔炭比表面积和中孔率分别高达2 009 m2·g-1和90.8%。其在50 m A·g-1电流密度下的比电容达176 F·g-1,即使在1 000 m A·g-1的大电流下,其比电容仍保持在126 F·g-1,表现出优异的倍率能力。所制介孔炭具有良好的循环稳定性,在200·m A g-1电流密度下的比电容高达150 F·g-1,1 000次循环无容量衰减。稻壳基介孔炭在超级电容器领域具有良好的应用前景。     

基于柠檬酸铁的介孔碳材料的制备及电化学研究

以柠檬酸铁为原料,采用直接碳化法,制备出介孔碳材料。通过SEM和TEM对其形貌进行分析,发现样品具有大量的孔道结构。N2吸附测试表明,所制备介孔碳MCs-800的比表面积高达1 918m2/g。采用TG技术研究了柠檬酸铁在氮气气氛中的热解过程。并用循环伏安法和恒电流充放电法进行电化学测试。测试表明,以柠檬酸铁为原料碳化所得的介孔碳的循环伏安图形接近矩形,在恒电流充放电过程中发现样品在不同的电流密度下均呈现出较规则的三角形,且阳极和阴极过程基本对称,表明样品具有良好的电化学稳定性和可逆性。     

高性能超级电容器用高比表面积、层次孔结构炭材料的简便制备(英文)

采用NaOH一步炭化-活化聚偏二氯乙烯(PVDC)简便制备出高比表面积、层次孔结构炭材料。该炭材料具有发达的微孔-中孔-大孔的层次孔结构,其比表面达到2 815 m·2g-1。独特的微结构使其在无机和有机电解液中都表现出高的比电容和优异的大电流性能。其在6 mol·L-1KOH电解液中以0.05 A·g-1电流充放电测得的比电容高达376F·g-1,电流密度增大到50A·g-1比电容还保持215 F·g-1。在有机电解液1 mol·L-1Et4NBF4/AN中的比电容也达到170 F·g-1(电流密度0.05 A.g-1),电流密度增大到20A·g-1比容量还保持124F·g-1。     

柠檬酸盐为碳前驱体制备介孔炭及其在电化学电容器中的应用(英文)

热解柠檬酸镁或柠檬酸钡,制备了两种介孔炭(MgC或BaC),并将其用作双电层电容器电极材料。采用氮气吸附、扫描电子显微镜和傅里叶红外光谱对所制介孔炭进行表征。结果表明:所制介孔炭孔结构与柠檬酸盐所含金属阳离子有关。其中,BaC呈典型的双峰孔径分布,最可几孔径分别为3.8nm和15nm;而MgC的孔道主要是小尺寸的介孔或微孔。通过循环伏安、恒流充放电法测试所制介孔炭作为电化学电容器电极材料时的电化学性质。测试表明,在离子液体中MgC和BaC都具有很高的比电容值,分别达到180F.g-1和171F.g-1。其中,BaC的倍率性能良好,能量密度可达到53.3Wh.kg-1,最大功率密度为20kW.kg-1。BaC优良的电容特性主要归因于其孔径双峰分布的孔结构和亲水性表面化学性质。     

酚醛基碳气凝胶的常压制备及电化学应用

本研究利用线性酚醛树脂体系,以溶胶-凝胶法在常压条件下制得有机气凝胶,并进一步碳化制备出碳气凝胶.研究发现,该碳气凝胶经过KOH活化后,具有微/介/大孔的分级孔结构,且比表面高达2091.87 m2·g-1.对材料进行电化学性能研究发现,其在1 A·g-1电流密度下,比电容为282.3 F·g-1.在600 W·kg-...     

介孔碳微球的氢醌改性及电容性能研究

由于纯碳材料单一的双电层储能机理, 其比电容较低, 而赝电容材料可利用法拉第反应进行能量存储, 可以获得较高的比电容。作者利用软模板法制备出具有三维有序结构的介孔碳微球, 然后采用水热法制备氢醌改性的介孔碳微球。循环伏安和恒流充放电测试表明, 氢醌改性使得介孔碳微球不仅具有双电层电容, 而且具有赝电容。负载10wt%氢醌的介孔碳微球具有最大的比电容值, 当电流密度为0.5 A/g时, 其比电容值高达285 F/g; 当电流密度增大到10 A/g时, 其比电容值仍高达212 F/g, 表现出优异的倍率特性。这主要归因于氢醌以π-π堆叠方式负载在碳质介孔表面, 不仅提供了额外的赝电容, 而且提高了碳材料在水系电解液中的倍率特性。     

NiCo_2O_4微球的制备及其电化学性能

通过简单的水热法以及后续热处理,成功合成介孔NiCo_2O_4微球。利用FESEM、TEM、XPS和电化学工作站对样品的表面形貌、元素价态和电化学性能进行表征。结果表明:合成的NiCo_2O_4拥有丰富的多孔纳米针状结构,表现出较高的比表面积。由于这种三维多孔纳米结构,当NiCo_2O_4微球作为电极材料时,展现出优异的电容特性,在1A·g-1的电流密度下比电容高达1 554F·g-1,而且当电流密度增加到20A·g-1时,电容保持率为87.5%。另外,在5A·g-1的电流密度下,经过2 000次的充放电循环后,比电容仍能保持初始电容的90.4%。良好的电化学性能表明,NiCo_2O_4微球是一种理想的超级电容器电极材料。     

超级电容器用聚苯胺/有序介孔炭复合电极的性能

利用原位聚合法制备了聚苯胺/有序介孔炭复合材料.通过恒流充放电、循环伏安和交流阻抗测试考察了不同聚苯胺含量对聚苯胺/有序介孔炭复合材料电化学性能的影响.研究表明:与纯的有序介孔炭和聚苯胺相比,聚苯胺/有序介孔炭复合材料具有更高的比容量,良好的稳定性和充放电循环性能.当聚苯胺质量分数为60%,电流密度为0.1A·g-1时,比容量可以达到409F·g-1.     

电弧法制备石墨烯的孔结构和电化学性能研究

利用电弧法制备得到石墨烯(graphene)材料,并对其孔结构和电化学性能进行了研究.结果表明,利用电弧法制得的石墨烯具有发达、开放的介孔结构,比表面积为77.8m2/g,中孔率高达74.7%.作为电化学电容器电极材料,其在7mol/L的KOH电解液中比电容为12.9F/g,大电流性能优异,在200mV/s下的循环伏安曲线仍为矩形,交流阻抗谱的特征频率高达18.5Hz,体现出具有十分优异的倍率性能。     

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.