水性磺酸型聚氨酯/聚吡咯导电材料的制备、微观结构及成膜机理

以2,4-二氨基苯磺酸钠为亲水扩链剂,通过预聚体法合成了水性磺酸盐型聚氨酯分散液(SWPU)。并在FeCl3氧化剂的作用下,采用原位化学氧化聚合法制备了系列不同聚吡咯(PPy)质量浓度的水性聚氨酯/聚吡咯(SWPU/PPy)分散液,并通过溶液浇铸法制得系列复合导电薄膜。随着PPy的引入,SWPU分子与PPy分子间发生反应,SWPU/PPy的高温热稳定性亦得到提高。随着吡咯质量浓度的增加,SWPU/PPy乳胶粒的粒径增加。经适量PPy改性后,PPy可在SWPU胶束内部和表面均匀分布,形成大小均匀的纳米复合粒子;SWPU/PPy复合膜表面粗糙度下降,SWPU与PPy间具有较好的相容性。但当PPy质量浓度高于15%时,开始呈现一定的颗粒形貌,且薄膜表面粗糙度随着PPy浓度的增加明显增加;当PPy质量浓度高于30%时,胶膜表面颗粒形貌明显,胶膜表面主要由PPy组成。复合薄膜的渗透阈值介于质量浓度为1.5%~2%之间,当Py质量浓度为30%时,电导率高达1S/cm。     

含磺酸盐有机硅聚醚新型复合材料的制备与导电性能

采用原位吸附聚合法,使吡咯单体在含磺酸盐有机硅聚醚乳胶表面吸附聚合制备导电复合材料,研究了制备条件如投料比、投料顺序、反应条件及有机硅等对含磺酸盐有机硅聚醚导电性能的影响。结果表明,吡咯用量为12%,n(FeCl3)∶n(蒽醌-2-磺酸钠)∶n(吡咯)=2.2∶1.2∶1,投料顺序为含磺酸盐有机硅聚醚、吡咯、蒽醌-2-磺酸钠(AQS)、FeCl3,反应温度0℃(冰浴),充氮气保护,反应时间为3h制备的导电磺酸盐有机硅聚醚复合材料,体积电阻率低,导电效果最佳。     

TDI改性梳状有机硅聚醚复合材料的制备及导电性能

采用原位吸附聚合法,使吡咯单体在有机硅聚氨酯(TESO)乳胶表面吸附聚合制备了导电复合材料,研究了投料比、投料顺序及反应条件等对有机硅聚氨酯导电性能的影响。结果证明:吡咯用量12.5%,FeCl3、蒽醌-2-磺酸钠与吡咯摩尔比为2.2∶2.5∶1,投料顺序为TESO-吡咯-蒽醌-2-磺酸钠-FeCl3,反应温度0℃,pH=3,制备的复合材料导电效果最佳。TESO乳胶中的Si与导电聚吡咯具有协同效果,利于聚吡咯与TESO形成互通网络结构,在TESO乳胶表面或界面处形成连续核壳型导电聚合物膜层。     

水基阳离子聚氨酯/聚吡咯导电材料的原位制备与电阻性能

以N-甲基二乙醇胺(MDEA)为扩链剂,聚乙二醇(PEG1000)、异佛尔酮二异氰酸酯(IPDI)为原料,通过预聚体法制备了系列水基阳离子聚氨酯分散液(CWPU)。再以FeCl3为氧化剂,在CWPU中进行吡咯的原位化学氧化聚合制备聚氨酯/聚吡咯(CW-PU/PPy)复合导电材料。红外光谱图表明PPy与CWPU分子间存在氢键缔合。经PPy改性后,CW-PU/PPy的分散液的平均粒径由10.61nm增加至30.29nm,粒径分布系数由0.850下降至0.346。原位聚合过程中PPy能均匀包裹于CWPU胶粒表面,CWPU/PPy分散液胶粒呈球形结构,彼此间相互独立。实验结果亦表明,当Py浓度为20%、反应温度为40℃、反应时间为2h、n(FeCl3)/n(Py)=2.0时,CWPU/PPy复合薄膜的表面电阻率可达到20Ω.cm。     

聚吡咯/凹凸棒石水性导电涂料的制备

用吡咯单体(Py)在凹凸棒石(ATP)的表面发生原位聚合反应,制备出聚吡咯/凹凸棒石(PPy/ATP)纳米导电复合材料.通过Fourier红外光谱、X射线衍射、扫描电子显微镜对复合材料进行表征,结果表明聚吡咯的包覆没有破坏凹凸棒石的晶体结构,两者之间作用仅为物理作用.以PPy/ATP为填料制备的水性丙烯酸涂料导电性高于以PPy为填料制备的水性丙烯酸涂料,并通过SEM研究了涂层的导电机理,表明PPy/ATP在导电涂料中具有更为广阔的应用前景.     

聚吡咯/还原氧化石墨烯导电填料的制备及应用

将氧化石墨超声分散,在水合肼的作用下制备了在水相条件下稳定分散的还原氧化石墨烯(RGO);以十六烷基三甲基溴化铵(CTAB)为模板剂,RGO为掺杂剂,吡咯单体为原料,六水合三氯化铁(FeCl_3·6H_2O)为引发剂聚合制备聚吡咯/还原氧化石墨烯(PPy/RGO)导电复合材料。利用傅里叶红外光谱、X射线衍射和透射电子显微镜等手段对复合材料的理化性质进行表征,结果表明线状PPy成功聚合在RGO表面;热重分析和电导率测试结果显示,复合材料相对于PPy具有更高的热稳定性和电导率,电导率可达14S/cm。将PPy/RGO复合材料水性聚氨酯乳液制成复合涂层,考察了涂层的抗静电性能,发现PPy/RGO复合材料具有更低的逾渗阈值。     

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。     

原位还原制备磺酸型水性聚氨酯/纳米银复合材料及其表征

使用水溶性聚酯多元醇(BY3301)和磺酸盐扩链剂氨基磺酸钠(A95)与四甲基苯二甲基二异氰酸酯(TMXDI)合成了磺酸型水性聚氨酯(SWPU)。在SWPU中原位还原纳米银(AgNPs)制备了磺酸型水性聚氨酯/纳米银(SWPU/AgNPs)复合乳液。涂膜之后测试了复合材料的力学性能、热性能和粘接性能的变化。同时使用动态光散射(DLS)和透射电镜(TEM)测试了乳液的粒径分布以及AgNPs的尺寸。结果表明,原位还原引入的AgNPs可以提高复合材料的力学性能和热性能,对于SWPU的粘接性能影响不大。SWPU在复合材料中还起到了稳定剂的作用,有效避免了AgNPs的团聚。TEM的研究显示复合材料中的AgNPs的形状为球形,粒径范围在5~40 nm。     

原位还原制备磺酸型水性聚氨酯/纳米银复合材料及其表征EI北大核心CSCD

使用水溶性聚酯多元醇(BY3301)和磺酸盐扩链剂氨基磺酸钠(A95)与四甲基苯二甲基二异氰酸酯(TMXDI)合成了磺酸型水性聚氨酯(SWPU)。在SWPU中原位还原纳米银(AgNPs)制备了磺酸型水性聚氨酯/纳米银(SWPU/AgNPs)复合乳液。涂膜之后测试了复合材料的力学性能、热性能和粘接性能的变化。同时使用动态光散射(DLS)和透射电镜(TEM)测试了乳液的粒径分布以及AgNPs的尺寸。结果表明,原位还原引入的AgNPs可以提高复合材料的力学性能和热性能,对于SWPU的粘接性能影响不大。SWPU在复合材料中还起到了稳定剂的作用,有效避免了AgNPs的团聚。TEM的研究显示复合材料中的AgNPs的形状为球形,粒径范围在5~40 nm。     

聚吡咯材料导电性的量化计算及实验研究

采用密度泛函理论对吡咯(Py)和聚吡咯分子(PPy)进行全优化,并在b31yp/6-31g(d)水平上计算了Py和PPy分子中氮原子的电荷密度、最高占据分子轨道(HOMO)能量、最低空轨道(LUMO)能量和能带隙(ΔE)。从理论角度探究了Py和PPy分子结构与导电性的关系。在理论分析预测的基础上,选择合适的氧化剂和掺杂剂及其在实验中适宜的用量,采用化学氧化法制备不同反应温度下的PPy,探讨了反应温度对PPy聚合度及其导电性能的影响。结果表明：PPy的聚合度越大,其导电性就越好;低温有利于制备聚合度较高和电导率较好的PPy。     

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.……     

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.     

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.     

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 ...