聚硅氧烷对水性聚氨酯聚合物电解质结构形态及电化学性能的影响

将PDMS引入到WPU中,合成了PEO-PDMS混合软段WPU嵌段共聚物,通过改变PDMS的含量得到一系列固态聚合物电解质膜。测试结果表明,PDMS的加入会对聚合物电解质材料的力学性能、微观形态、电化学性能产生显著影响。PDMS的加入可有效地提高聚合物电解质的室温电导率及电化学稳定性,30℃时样品C17-10电导率为1.05×10-4S/cm,其电化学稳定窗口达到5.5V。     

PEO-Li1.3Al0.3Ti1.7(PO4)3复合聚合物电解质的制备与电导率研究

将实验室制备的两种烧结型的Li1.3Al0.3Ti1.7(PO4)3盐与PEO/LiClO4复合,制得了PEO-LiClO4-Li1.3Al0.3Ti1.7(PO4)3复合聚合物电解质,测量了298～373K温度范围内的阻抗,得出这种体系的复合聚合物电解质的离子电导率在室温最高值为1.387×10-5S/cm,在373K时可达到1.378×10-3S/cm.     

水性聚氨酯-聚二甲基硅氧烷共混体系固态聚合物电解质的光谱学研究

以水性聚氨酯(WPU)-聚二甲基硅氧烷(PDMS)共混体系为聚合物基体,通过添加不同质量分数的高氯酸锂(LiClO4)得到一系列固态聚合物电解质.交流阻抗测试结果显示,当LiClO4质量分数为15 %时体系电导率最高,并且温度与电导率关系基本符合Arrhenius方程.采用傅立叶红外光谱(FT-IR)对聚合物电解质中锂离子与羟基及醚氧基之间的相互作用分析显示,当LiClO4质量分数为15%时,锂离子与羰基及醚氧基的配位作用均达到饱和状态.拉曼光谱(Raman)研究结果表明,该聚合物体系对盐具有较好的溶解能力,增加盐浓度后,可使体系中有效离子的相对比例增加,有利于离子传输.     

聚氧化乙烯-聚硅氧烷基离子液体复合聚合物电解质的研究

通过对不同聚硅氧烷(PDMS)含量的聚氧化乙烯-聚硅氧烷(PEO-PDMS)聚合物电解质电化学性能的测试,确定出PDMS最佳添加量,并以此聚合物配比为基体,通过复合不同质量分数的离子液体1-丁基-3-甲基咪唑双三氟甲磺酰亚胺盐([BMIM]TF-SI)或N-甲基、丙基哌啶双三氟甲磺酰亚胺盐(PP13TFSI),制备得到不同体系的离子液体复合聚合物电解质膜。离子液体的加入可显著提高聚合物电解质的室温电导率,样品PPP-100%室温电导率达到5.6×10-4S/cm。同时,样品均具有良好的热学和电化学稳定性。通过两种体系聚合物电解质性能对比得知,PP13TFSI离子液体复合聚合物电解质具有更优性能,有望作为新型电解质材料应用在锂离子电池中。     

PVDF-HFP基复合多孔聚合物电解质膜的研制

聚偏氟乙烯-六氟丙烯共聚物(PVDF-HFP)多微孔膜在锂离子电池领域中具有很好的应用前景.采用Bellcore制膜法,用纳米材料对PVDF-HFP为基质的聚合物微孔膜材料进行了改性.利用XRD,SEM,交流阻抗等测试手段对电解质膜的晶体结构、微观形貌、电化学性能等进行了表征.结果表明:改性后聚合物电解质膜的孔隙率增加、结晶度降低,PVDF-HFP/SiO2和PVDF-HFP/Al2O3聚合物电解质隔膜的电导率(20℃)分别达到2.762×10-3S/cm和3.517×10-3S/cm,相应的离子迁移数分别为0.80和0.82.     

离子液体1-丁基-3-甲基咪唑四氟硼酸复合聚氧化乙烯制备凝胶聚合物电解质及研究

以十六烷基聚乙二醇甲基丙烯酸酯(HPEGM)和甲氧基聚乙二醇甲基丙烯酸酯(MPEGM)为单体,离子液体1-丁基-3-甲基咪唑(BmimBF4)为增塑剂,高氯酸锂(LiClO4)作锂盐,采用自由基溶液聚合法制备凝胶聚合物电解质(PGE)。用红外光谱(FT-IR)、差热分析(DSC)和交流阻抗(AC)等方法对聚合物电解质的结构与性能进行了研究。测试结果表明:离子液体对聚合物基体起到了很好的增塑作用,促进了聚氧化乙烯(PEO)链段的运动,有利于离子传输;当m(HPEGM)∶m(MPEGM)∶m(BmimBF4)=1∶4∶10,n(Li+)∶n(EO)=1∶20时,30℃下,聚合物电解质的离子电导率可达1.10×10-3 S/cm;聚合物电解质膜显示出优良的热稳定性;电化学窗口达4.6V。     

线性与超支化聚氨酯共聚体系固体电解质的研究

用超支化和线性聚氨酯的低交联共聚物(CHPU)作为聚合物基体,LiClO4为离子源制备了一系列的聚合物固体电解质。DSC分析显示该共聚物比共混物(MHPU)玻璃化转变温度低,红外和Raman光谱显示该共聚物比共混物对盐离子的溶解性能更强,同时该体系比共混物体系有更高的电导率,25℃时CHPU30/LiClO4体系的最佳电导率达到1.5×10-5S/cm。     

侧链枝化的磷酸酯型聚合物电解质的合成与性能研究

以聚乙二醇200、二乙二醇单甲醚等与三氯氧磷反应制备得到枝化结构的磷酸酯单体,其末端为丙烯酸酯基团。紫外引发聚合制备聚合物电解质,考察了磷酸酯单体的分子量、温度、盐浓度对聚合物电解质电导率的影响。研究表明,在测试盐浓度下,复合体系的最大室温电导率对应的LiClO4盐浓度都为5%,PEP200_3与LiClO4复合后室温电导率最高,可达1.80×10-5S/cm。     

纳米 SiO 2/ LiClO 4/ PVDF2 HFP复合凝胶聚合物电解质的制备及其电化学性能

为了解决液态电解质锂离子电池存在的安全性问题 , 以偏氟乙烯和六氟丙烯的共聚物( PVDF2 HFP)为基体 , 通过加入高氯酸锂(LiClO 4) 、 增塑剂(碳酸丙烯酯和碳酸二甲酯) 、 纳米二氧化硅等 , 制备出了具有高电导率的复合凝胶聚合物电解质。用 X射线衍射仪测试聚合物电解质的结构 , 用交流阻抗法测定其电导率 , 用线性伏安扫描法研究了该聚合物电解质体系的电化学稳定性 , 并以其为电解质制备成锂离子电池进行充放电测试。结果- 3表明 , 在 20℃ 时复合凝胶聚合物电解质的电导率最高可达 7. 56×10 S/ cm , 该电解质在 41 6 V 以下电化学窗口稳定 , 以其为电解质的锂离子电池具有良好的电化学性能 , 说明纳米 SiO 2/ LiClO 4/ PVDF2 HFP复合凝胶聚合物电解质能满足锂离子电池的应用。     

三(甲氧基聚乙二醇)-铝酯锂离子电池聚合物电解质的制备与研究

以甲氧基聚乙二醇甲基丙烯酸酯(MPEGM)和十六烷基聚乙二醇甲基丙烯酸酯(HPEGM)为单体,三(甲氧基聚乙二醇)-铝酯(MPEG-Al酯)为增塑剂,锂盐为高氯酸锂(LiClO4),采用自由基溶液聚合法制备了聚合物电解质P(MPEGM-HPEGM)/MPEG-Al。用红外光谱(FT-IR)、差热分析(DSC)和交流阻抗等方法对聚合物及电解质的结构与性能进行了研究。测试结果表明,MPEGM和HPEGM共聚生成P(MPEGM-coHPEGM);聚合物中聚氧化乙烯(PEO)链段的运动能力得到提高,有利于离子传输;聚合物电解质膜具有优良的热稳定性和电化学稳定性;以MPEG7-Al为增塑剂,当m(MPEGM)∶m(HPEGM)∶m(MPEG7-Al)=4∶1∶5,n(Li+)∶n(EO)=1∶20时,30℃下,聚合物电解质的离子电导率最高达到0.43×10-3S/cm;离子迁移数达到0.3;电化学窗口为4.8V。     

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.……     

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...     

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.……     

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.     

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.     

Synthesis of Alumina-Zirconia Nanocomposites by Solgel Process

Al₂O₃-ZrO₂ nanocomposites were developed starting with the solgel process. Composite alumina-zirconia nanopowders were synthesized from metallorganic precursors (Aluminium secondary butoxide and zirconium Iso propoxide) using the solgel process. The parameters affecting the synthesis—solvent, concentration of precursor, R/H ratio (i.e., dilution of water in solvent)—were varied as also the temperature and pH. BET and TEM were used to measure nanosize. Diffuse reflectance spectroscopy and also qualitative optical absorption led to identical particle size estimate. The variation of process parameters was used to study the effect and interdependence of process parameters. Artificial Neural Networks was used to rigorously analyze the process. Although this led to confirmation of interdependence of parameters, the presence of a single overwhelming solvent variable was also established. Then the optimal process was used to synthesize more nanopowder. To produce bulk nanocomposite the nanopowders were sintered by varying the temperature and time period. The sintered lithoids were probed with a vickers hardness tester to measure elastic modulus, hardness, and fracture toughness. The results showed high elastic modulus, modest hardness, and very high fracture toughness.