高分辨裂解气相色谱—质谱研究聚吡咙的热分解

用高分辨裂解气相色谱－质谱考察了不同聚吡咙的热分解，分析了其热分解产物的组成，分布和归属，研究了其环化过程以及该过程对热分解的影响，进而详细阐述了聚吡咙的热分解机理。     

聚吡咙基柔性碳膜的制备及电化学性能研究

将聚吡咙和不同浓度聚酰亚胺前驱体的溶液混合，采用静电纺丝和高温碳化技术，通过表面形貌观察、结构表征和电化学测试对柔性纤维膜进行分析。结果表明，由于聚吡咙与聚酰亚胺二者结构相似，具有良好的相容性；纳米纤维膜经过氮气气氛亚胺化、碳化后表现出优异的柔韧性，可直接作为锂电自支撑负极材料。当聚吡咙与9%(wt,质量分数)聚酰亚胺的质量比为85∶15,电流密度为50mA/g时，经100圈循环后，仍有378.7mAh/g的放电比容量。     

炭膜制备及其高效氧氮分离性能

通过论述炭膜的制备方法及其关键影响因素，系统总结了炭膜的氧氮分离性能，并将其与高性能聚吡咙膜和聚苯胺膜进行了比较，提出了今后的发展方向。指出炭膜具有优异的氧氮分离性能，其氧氮分离因子一般为10以上，最高可达36。聚酰亚胺基和聚吡咙基炭膜均表现出较好的综合氧氮分离性，大大突破了富氧膜材料的Robeson上限，位于极具吸引力的商业化区域，在空气分离中显示出了极大的应用潜力和工业化前景。     

聚硅烷的热分解动力学研究

用热重法（ＴＧＡ）研究了聚（甲基环己基硅烷）、甲基环己基硅烷与甲基苯乙基硅烷共聚物和聚（甲基苯乙基硅烷）的热分解动力学，计算了热分解动力学参数。结果表明，其热分解活化能分别为２０８ｋＪ／ｍｏｌ、１８７ｋＪ／ｍｏｌ和１１４ｋＪ／ｍｏｌ；这３者的热分解均符合无规引发裂解模型。     

PTBC和PTBMA的合成,水解及热分解研究

用阴离子聚合法合成了分子量分布较窄的聚2-丁烯酸特丁酯(PTBC)和聚α-甲基丙烯酸特丁酯(PTBMA)。通过对两种聚合物的水解、热分解的研究发现,PTBC的水解率可由反应时间和反应温度加以控制,水解产物可溶于极性溶剂中。热分解过程中无炭化和残留现象,并且其热分解起始温度适宜,热分解温度范围较宽,完全适合于作为新陶瓷材料加工成型的新型结合剂。     

聚1,2-亚丙基碳酸酯/橡胶体系的热分解

用动态热重分析（TG）研究了聚1，2－亚基碳酸酯（PPC）／橡胶共混弹性体的热分解反应，讨论了PPC／橡胶的热失重情况，动力学研究表明，热分解主要有3个过程，反应程度α＜0．1时主要是防老剂，促进剂等有机配合剂的挥发失耗阶段，第二阶段主要是PPC相的失重，其活化能不断升高；第三阶段是橡胶相的失重过程。3个反应阶段都是一级反应。热分解活化能数据验证了1，2－亚丙基碳酸酯（PPC）／丁苯橡胶（SBR）弹性体中PPC与SBR形成界面互穿网络，网络互穿部分热分解活化能明显升高。马来酸酐的加入使相界面分子链的缠绕互穿更加完全。     

水溶性聚偶氮酯的研究

用Ｐｉｎｎｅｒ合成方法制备了用ＰＥＧ４００封端的水溶性聚偶氮酯，并表征了其结构；研究了热分解反应动力学及用于乳液聚合的动力学。结果表明，该种引发剂具有引发速度快、热分解机理简单和具有辅助乳化作用等优点。     

甘蔗渣对聚甲基丙烯酸甲酯热降解的影响

目的分析生物质材料对塑料废弃物热降解的影响,以聚甲基丙烯酸甲酯(PMMA)为对象,探讨甘蔗渣对其热分解行为和动力学的作用。方法利用溶液共混法制备PMMA/甘蔗渣混合物,采用热失重法研究其在氮气中的热分解过程,通过最大失重速率法和Ozawa等失重法计算PMMA热分解反应的动力学参数活化能和频率因子。结果甘蔗渣使得PMMA的初期热分解温度明显降低,但是PMMA的热分解活化能和频率因子却都显著增加。最大失重速率法的计算结果表明,PMMA加入甘蔗渣后的热分解活化能增加了26.2 k J/mol,等失重法的结果显示活化能和频率因子分别为168.14 k J/mol和28.41 min-1,比纯PMMA相应地增大了72.6 k J/mol和12.52 min-1。结论甘蔗渣的加入对PMMA的热降解有显著的影响,使其热分解变得困难,因此有必要进一步探讨其他生物质对PMMA热分解的影响。     

PBAMO的热分解反应机理

采用无模型法对聚3,3-双叠氮甲基环氧丁烷(PBAMO)的热分解反应动力学进行了计算,并用热重-红外-质谱(TG-IR-MS)联用技术研究了其热分解反应产物。PBAMO表现出了独特的热分解过程,TG曲线中在210℃~270℃叠氮基团的分解失重之后没有第二个明显的失重台阶;PBAMO第一阶段的热分解活化能为150 kJ/mol,当分解率大于0.4时,活化能降为负值。TG-IR-MS结果表明,在叠氮基团分解时释放的热量加速了剩余氮原子的氧化还原过程,主要产物形式为NO,主链中的氧原子被消耗掉,从而导致了碳链骨架的大量残留。     

预氧化聚碳硅烷纤维热分解动力学及其机理

利用动态TGA分析和Coats-Redfern模型研究了预氧化聚碳硅烷(PCS)纤维的热分解动力学,用IR、XRD、SEM和HRTEM等研究了其热分解过程与机理。结果表明,预氧化PCS纤维热分解过程为一级反应,表观活化能为19.826kJ/mol;在初始分解阶段,主要为小分子PCS逸出,≡Si-H键之间以及≡Si-H与≡Si-CH3键发生了脱氢、脱CH4反应,从而导致交联程度的增加;随热分解温度进一步提高,分子的有机侧链急剧热解,分解产物从有机物转变为存在部分微晶的无机结构;热分解温度继续提高,纤维无机化结构进一步完善,β-SiC晶粒尺寸增加,纤维中出现自由碳;1250℃以上,β-SiC晶粒急剧长大,晶粒尺寸增加导致SiC纤维的力学性能下降。     

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.     

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...     

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.     

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.     

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.     

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.     

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.