超级电容器MnO2/CRF复合电极材料的制备及性能的研究

以间苯二酚(R)和甲醛(F)为原料,碳酸钠(C)为催化剂,制备碳气凝胶(CRF),并以KMnO4和Mn(CH3COO)2·4H2O为原料,采用了化学沉淀法制备MnO2/CRF复合材料.用N2吸附、X射线衍射(XRD)和扫描电镜(SEM)对所制备的MnO2、CRF和MnO2/CRF复合材料进行了表征,结果表明碳气凝胶具有珍珠串式的无序多孔网络结构,所制备的MnO2为纳米级颗粒,复合材料为纳米级粉体.并对不同配比的MnO2/CRF复合材料的电化学性能进行了研究.循环伏安、恒流充放电实验表明了所制备的MnO2/CRF复合电极材料具有良好的可逆性和充放电性能.当MnO2含量为60%时,MnO2与碳气凝胶复合制成的新型电极材料具有226.3F/g的比电容,比碳气凝胶电极的比电容提高了1倍.此外,对复合电极的循环寿命进行了研究,表明复合电极具有良好的循环充放电性能.     

铜掺杂钴氧化物CuxCo3-xO4的制备及其电化学电容性能

采用X射线衍射(XRD)、场发射扫描电镜(FESEM)对铜掺杂钴氧化物(CuxCo3-xO4)纳米粒子样品的结构和形貌进行了表征;用循环伏安,恒流充放电,交流阻抗等电化学方法对其电化学性能进行了测试。结果表明:钴和铜的摩尔比对目标产物的电化学性能有显著的影响,当钴和铜的摩尔比为2.67∶0.33时,样品的电化学性能最佳。在电流密度为1A/g时,比电容达到492F/g,且在3A/g的电流密度下,经过2000次充放电循环后,其比电容值没有衰减,表明Cu0.33Co2.67O4是一种良好的超级电容器电极材料。     

Co3O4/石墨烯复合物的水热合成及其超级电容器性能

采用水热法制备了Co3O4/石墨烯复合物,用XRD、FTIR和TEM测试了样品的结构和形貌,采用循环伏安法(CV)、交流阻抗和恒电流充放电测试分别研究了Co3 O4/石墨烯复合物电极的电化学性能.结果表明:石墨烯的掺入增加了Co3O4作为电极材料的可逆性,并降低了Co3O4纳米粒子与电解液的接触电阻和Warburg扩散阻抗.在6mol/L的KOH电解液中,复合物的比电容高达562F/g,1000次循环后比电容仅仅下降了2.6％.     

Co3O4/GO复合材料的制备及其对Pb2+和Cd2+的电化学检测

通过简单的水热-热分解法制备了Co3O4/GO复合材料,利用场发射扫描电子显微镜(FESEM)、X射线衍射(XRD)、傅里叶红外光谱(FT-IR)、拉曼光谱(Raman)对样品进行结构形貌表征.将制备的Co3O4/GO复合材料作为电极修饰材料构建电化学传感器对溶液中的Pb2+和Cd2+进行检测,测试采用差分脉冲阳极溶出...     

聚吡咯/硝酸活化碳气凝胶复合材料在超级电容器中的应用

用溶胶-凝胶法制备出碳气凝胶,对其进行硝酸活化,与聚吡咯复合(化学氧化聚合法)及先活化后复合,探究活化、复合对碳气凝胶性能的影响。采用傅立叶变换红外光谱仪和扫描电子显微镜表征材料的成分和形貌,通过循环伏安法、恒流充放电、交流阻抗及循环性测试等考察材料的电化学性能。结果表明,最佳处理方式为先活化后复合。比电容量大大提高,约为纯碳气凝胶的3倍,扫描速率为5mV/s时,比电容量达311F/g;1000次循环后比电容稳定在较高数值;导电性也得到提高。     

基于碳纳米管-Fe_xO_y复合材料电极的电化学性能

本文主要研究以碳纳米管(carbon nanotubes,CNTs)-FexOy复合材料作为电极分别在水溶液和凝胶电解质中的电化学性能。采用化学气相沉积法制备CNTs薄膜,并利用超声雾化热解法于不同的沉积时间下制备FexOy与其复合制作成电极。对复合电极进行形貌表征及电化学性能检测,包括循环伏安、恒流充放电及交流阻抗测试。结果分析表明,电极的比电容随着沉积时间的增加而增加,且均高于纯CNTs电极,同时界面电荷传递电阻随之减小;然而随着沉积时间的继续增大,样品比电容和能量密度明显下降。沉积10min样品在凝胶电解质的循环伏安测试中比电容达到最大值102.8 F·g-1。     

乙二胺改性Co3O4-NiO复合粒子的制备及其超级电容性能研究

利用简单液相共沉淀法制得中间产物Ni(OH)2-Co(OH)2,再经煅烧得到Co3O4-NiO复合粒子;用乙二胺对Co3O4-NiO复合粒子进行改性,改性后Co3O4-NiO微粒分散性提高,形貌为片状,片与片之间相互交叉形成疏松的介孔结构。电化学测试表明Co3O4-NiO电极材料在改性后表现出优良的电化学性能,在电位窗口为0～0.4V时,单电极比电容可达1202F/g,相比改性前提高了171F/g。     

添加过渡金属元素碳气凝胶的制备及性能

以间苯二酚(R)、甲醛(F)为原料,(R/F)摩尔比为1:2,通过掺杂一定量的硝酸铁或硝酸镍以改善碳气凝胶的结构与性能.用BET,XRD和SEM对碳气凝胶结构进行表征,结果显示样品同传统碳酸钠作为催化剂所得层状形貌结构有明显不同,样品中均含有球状颗粒,且掺杂硝酸铁的样品表面更粗糙,掺杂Ni2+所得碳气凝胶的比表面积高达441.8m2/g.电化学测试结果表明,掺杂Ni2+样品的比电容数值比掺杂Fe3+样品的和传统碳酸钠为催化剂所得碳气凝胶的来得更高,可达227.3F/g,其电化学性能较优.     

氢氧化钴/氢氧化镍复合材料的制备及电化学性能研究

过渡金属氧化物(氢氧化物)由于其优良的电容特性而受到极大的关注,其中Co(OH)_2和Ni(OH)_2是研究的热点。采用电化学沉积法制备不同摩尔比的Co(OH)_2/Ni(OH)_2复合材料,利用XRD和SEM对沉积产物进行结构和形貌表征,同时采用循环伏安法、恒电流充放电以及电化学阻抗谱对电极材料进行电化学性能测试。结果表明,电化学沉积法可以制备出不同摩尔比的Co(OH)_2/Ni(OH)_2复合材料,电极材料为纳米花状结构,而这种结构大幅增加了活性材料的比表面积。随着沉积溶液中Co(NO_3)_2或Ni(NO_3)_2含量的增加,Co(OH)_2/Ni(OH)_2电极材料的放电时间与比电容值呈现先增大后减小的趋势。其中,当沉积溶液中Ni(NO_3)_2∶Co(NO_3)_2=1∶1时,所沉积的Co(OH)_2/Ni(OH)_2复合材料的放电时间最长、比电容值最大,可达到841.15 F/g。     

己二酸辅助溶胶-凝胶法合成Li_4Ti_5O_(12)及其电化学性能

以己二酸为络合剂,通过溶胶-凝胶法合成了具有优良电化学性能的电极材料Li4Ti5O12。采用XRD、SEM、恒流充放电测试对材料的结构、形貌和电化学性能进行了表征。结果表明:通过该法制备的样品为颗粒细小均匀的立方尖晶石Li4Ti5O12纯相,并显示出优良的电化学性能;0.1C倍率下首次放电比容量为169.59mAh/g,经过30充放电循环后仍然保持在158.17mAh/g。在2.0C倍率下,其可逆容量仍可达到124mAh/g,表现出良好的倍率性能。     

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.