PPy/MWNTs/GO复合材料的制备与电化学性能研究

以吡咯为单体,多壁碳纳米管和氧化石墨烯为模板,过硫酸铵为氧化剂,采用原位化学聚合法制备了聚吡咯/多壁碳纳米管/氧化石墨烯(PPy/MWNTs/GO)复合材料.利用傅里叶变换红外光谱(FTIR)、X射线衍射谱(XRD)、扫描电镜(SEM)、循环伏安法(CV)和电化学交流阻抗谱(EIS)对制备复合材料的结构、微观形貌和电化学性能进行了研究,探讨了多壁碳纳米管/氧化石墨烯比例、吡咯用量对复合材料电容性能的影响.研究结果显示,PPy/MWNTs/GO复合材料具有较大的比电容和良好的循环稳定性,且具有较小的电荷转移电阻,接近于理想的超级电容器用电极材料.     

SnO2/还原氧化石墨烯/聚吡咯三元复合物的合成及其电化学电容性能

采用两步法制备出均匀分散的SnO2/还原氧化石墨烯(SnO2/RGO)二元复合物,再以二元复合物为模板,通过化学氧化法聚合吡咯(Py)单体,制备出SnO2/还原氧化石墨烯/聚吡咯(SnO2/RGO/PPy)三元复合材料。利用红外光谱(FTIR)、X射线衍射(XRD)和场发射扫描电镜(FESEM)对复合材料结构和形貌进行物性表征,利用循环伏安、恒电流充放电和交流阻抗对复合材料进行电化学性能研究,并讨论了不同含量的PPy对复合材料的结构和性能的影响。结果表明,所合成的三元复合材料的比电容随PPy含量的增加而增大,最大达到305.3F/g。三元复合物电容性能增强源于SnO2、RGO与PPy三者的相互协同作用,以及材料层状结构和大的比表面积。     

聚吡咯/石墨烯复合材料的制备和电化学电容性能研究

在70℃的酸性水溶液中,以氧化石墨烯为氧化剂,实现了吡咯的原位氧化聚合。采用傅里叶红外光谱(FTIR),X射线衍射(XRD),X射线光电子能谱(XPS)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)对复合材料的结构、形貌进行了表征;用循环伏安和恒流充放电对复合材料的电化学性能进行了研究。结果显示:吡咯吸附在氧化石墨烯的表面,发生了原位聚合反应;石墨烯剥离为片层,增大了复合材料的比表面积,聚吡咯/石墨烯复合材料显示了可观的电化学性能,在电流密度为0.5A/g时,电容量达到了695.5F/g,明显高于纯聚吡咯的比电容,循环稳定性也得到了提高。     

MEMS超级电容器膜电极材料的表面改性

为了改善MEMS超级电容器膜电极的致密性,通过在聚吡咯(PPy)中引入苯磺酸钠(BSNa)和氧化石墨烯(GO)表面改性功能薄膜,实现聚吡咯薄膜在MEMS超级电容器三维微结构上的均匀沉积.借助扫描电镜(SEM)、循环伏安测试(CV)、交流阻抗谱测试(EIS)、恒流充放电测试(CP)等手段对表面改性后的样品进行电化学性能测试.结果表明:当吡咯单体(Py)与BSNa摩尔比为1∶2,GO含量为0.4%时,在-0.4~1.0 V电压范围内,以100 m V/s速率扫描56圈,PPy薄膜的致密性最佳;表面改性可以在很大程度上减轻PPy颗粒的团聚,使得聚合后的PPy分子链排布紧密,形成了规整的网状立体结构;在放电电流为2 m A时,比容量可以达到13.3 m F/cm2,MEMS超级电容器的电化学性能得到改善.     

聚苯胺纳米纤维/石墨烯复合物的制备及其电化学性能

以氧化石墨烯(GO)为基体,采用界面聚合法制备了聚苯胺纳米纤维/氧化石墨烯的复合物(PA-NI/GO),经水合肼还原和APS再氧化得到聚苯胺纳米纤维/石墨烯复合物(PANI/GR)。用FT-IR、UV-Vis、XRD、SEM和TEM对复合物的结构和形貌进行表征,结果表明氧化石墨烯不仅为苯胺提供了聚合的基体,同时对聚苯胺有掺杂作用,聚苯胺纤维夹在片状石墨烯之间呈现"三明治"结构。通过循环伏安和恒流充放电测试发现,PANI/GR复合材料表现出双电层电容和法拉第赝电容双重特点,受协同效应的作用,在电流密度为400mA/g时,比容量高达460F/g,呈现出优异的电化学活性。     

聚吡咯/氧化石墨复合材料的制备及其电容性能

以氧化石墨为载体,采用木质素磺酸钠作为掺杂剂,氯化铁作为氧化剂,引发吡咯单体在氧化石墨层发生化学原位聚合反应,制备了聚吡咯(PPy)/氧化石墨复合材料。通过XRD、FTIR和SEM分析分别对复合材料的物相组成、结构和微观形貌进行了表征,通过TGA分析研究了复合材料的热稳定性,采用恒电流充放电、循环伏安和电化学阻抗谱等方法测试分析其电化学性能。研究表明:采用化学原位聚合的方法合成的PPy/氧化石墨复合材料具有"层-球"状的"三明治"型微观结构,以便形成良好的导电网络,其结晶度高、排列规整、缺陷少,复合材料中吡咯单体通过N-H键与氧化石墨的含氧官能团发生键合。PPy/氧化石墨复合材料新颖的微观结构和良好的化学键合状态使其表现出优异的电容性能。在电流密度分别为0.5、1.0、2.0和5.0 A/g时的比电容分别为500、460、427和396 F/g;经过1000次恒电流(2.0 A/g)充放电循环后, PPy/氧化石墨复合材料的比电容保持率为97.2%。      

聚吡咯/壳聚糖复合导电材料制备及其性能研究

电极材料是电容法去离子(CDI)技术的核心。为了提高聚吡咯(PPy)的吸附容量、电化学稳定性及其使用寿命,将壳聚糖(CS)和PPy复合制得PPy/CS复合导电材料。采用扫描电子显微镜(SEM)、红外光谱(FT-IR)和循环伏安法(CV)对PPy/CS复合导电材料进行表征。重点考察了氧化剂、CS、PPy及掺杂剂的用量对复合材料性能的影响规律。结果表明:PPy与CS结合形成了性能优良的导电聚合物复合材料;以三氯化铁(FeCl3)为氧化剂制得的PPy/CS复合导电材料性能更优,比电容达到0.46F/cm2;PPy/CS复合导电材料最佳制备参数为:CS用量1.5g、PPy用量70μL、FeCl3用量25mL、十二烷基苯磺酸钠(SDBS)用量50mL。     

不同水醇比条件下原位聚合的聚吡咯/石墨烯复合材料的电容性能

在不同水醇比的溶剂环境下,利用原位聚合法制得聚吡咯/氧化石墨烯复合物,再经还原得到聚吡咯/还原氧化石墨烯复合材料。通过红外光谱、扫描电子显微镜(SEM)、透射电子显微镜(TEM)等测试方法对复合材料的结构和形貌进行表征,利用电化学工作站对复合物的电化学性能进行了测试。结果表明,在不同水醇比的溶剂条件下所制备的还原氧化石墨烯与聚吡咯复合材料都具有优异的电容性能和良好的稳定性。当水醇比为9∶1(体积比,下同)时,所制备的材料具有最稳定的电容性能。     

PPy/AC电极的理化性能表征及电吸附除盐性能研究

为了提高活性炭电极在电吸附去离子实验中的除盐效果,实验采用化学原位合成法对活性炭进行负载聚吡咯改性,得到聚吡咯改性活性炭(PPy/AC)并制备电极,研究PPy/AC电极在硝酸钾溶液中的电吸附除盐性能。利用SEM、接触角测试仪、CV、EIS和GCD等多种表征手段分析改性前后活性炭电极的理化性质和电化学特性。结果表明,改性之后,活性炭电极的平均接触角从85.7°减小到60.45°,润湿性变好;比电容由89.66 F/g增加到283.5 F/g,提高了68.37%;电极的导电性变好,电阻变低,离子扩散属于半无限扩散过程;经过100次循环伏安测试后,比电容仅降低了20%,电极具有较好的循环稳定性和再生性。     

聚苯胺/聚吡咯复合薄膜电极的制备及其超电容和耐腐蚀性

在聚苯胺(PANI)和聚吡咯(PPy)的相应单体溶液中,采用循环伏安法(CV)在不锈钢基体(SS)上分层聚合制备了具有聚苯胺/聚吡咯复合薄膜(PANI/PPy/SS)的电极材料。用傅里叶变换红外光谱(FT-IR)、X射线衍射(XRD)对其结构进行了表征。在0.5mol/L H2SO4中,对PANI/PPy/SS电极材料进行了循环伏安法、恒流充放电、交流阻抗谱(EIS)等电化学性能测试,并用塔菲尔曲线(Tafel)研究了其耐腐蚀性能。结果表明,当电流密度为5mA/cm2时,PANI/PPy/SS电极材料比电容达747.5F/g,且复合膜的腐蚀电位相对于单纯的PANI、PPy薄膜分别正移了0.064V、0.117V,表现出较好的耐腐蚀性,是一种应用前景很好的超级电容器材料。     

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.     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

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.……     

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.     

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.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.