氧化煤焦油沥青的初期炭化过程

引言从中间相沥青制碳纤维时不熔化是一关键工段,通常沥青纤维是通过空气中氧化处理使之不熔化,因氧化聚合反应使沥青分子间形成交联被看作是不熔化的主要原因。然     

中间相沥青碳纤维径向辐射结构形成机理研究

中间相沥青碳纤维(MPCF)由于沥青分子沿轴向高度取向,其径向结构容易呈现辐射状态.为研究辐射形成机理,研究了相同的不熔化沥青纤维在不同炭化温度下得到的中间相沥青碳纤维的径向结构.通过SEM,DSC,XRD,FT-IR以及强度测试表征发现,在不熔化纤维和较低炭化温度得到的碳纤维内部沥青分子通过含氧官能团交联,结构致密,...     

中间相沥青纤维的预氧化和应力应变行为研究

采用傅里叶红外和动态热机械分析仪对中间相沥青纤维预氧化过程进行研究。结果表明,纤维中的应力在175℃前迅速降低;在氧化过程中,脱氢反应显著,同时羟基减少;到250℃以上醚键增加,大量的交联反应发生,应力增大,在恒定应力下纤维伸长速率减缓;270℃以上时纤维稳定化程度较高,产生收缩;整个氧化过程中含氧官能团的增加并不显著。结合纤维在垂直和水平两种状态下的受力分析认为,连续预氧化时,沥青纤维自身重力不容忽略,沥青预氧化炉宜采用立式设计。     

中间相沥青不熔化纤维自烧结制备高传导性炭材料研究

以中间相沥青为原料,通过带形截面喷丝板进行熔融纺丝,对所获中间相沥青纤维进行适度氧化处理,而后通过热压工艺将氧化中间相沥青纤维进行无黏结自烧结成型,并借助红外分析和扫描电镜等手段研究了不同最终氧化温度对带状沥青纤维的官能团变化与由其自烧结制备高导热炭材料的成型性及性能影响。结果表明:经260℃不熔化处理的中间相沥青纤维热压成型,能获得具有高密度、高抗弯强度和高传导性的新型炭材料,所制备材料的密度高达2.16 g/cm3,抗弯强度达到125.9MPa,电阻率和热导率分别达到0.56μΩm和830W/(m.K)。     

煤沥青热聚合过程对微孔炭特性的影响

煤沥青是一种热塑性物质,作为制备高比表面积微孔炭的原料需要进行不熔化处理.煤沥青经氧化聚合后,挥发分由52.22%下降到16%以下,相应的甲苯不溶物含量由30%增加到81%以上.IR光谱分析发现:沥青氧化聚合的结果表现为3000～2900cm-1附近甲基、亚甲基振动峰逐渐消失,1600cm-1附近C=C芳环骨架振动峰、744cm-1处渺位构型取代基峰同样显著减弱,通过脱亚甲基与渺位H实现芳环的稠和聚合,从而降低了稠和分子的芳香性.为此以中温煤沥青为原料制备高比表面积活性炭时需要选择适宜的加热氧化速度,以保持前驱体的反应活性.制备高比表面积活性炭时,要求前驱体中的中间相保持适宜尺度,并高度呈分散状分布于各向同性沥青之中.以本试验制备的前驱体采用KOH活化与炭化时发现:其BET、孔径分布与沥青氧化聚合工艺条件有关,中孔主要集中于2～3 nm、微孔分布主要集中在1.4nm附近,基本不含5nm以上的孔.     

沥青基活性碳纤维研究：1.沥青纤维的不熔化处理

利用热分析，红外光谱研究了通用型沥青纤维的不熔化机理，同时对影响不熔化反应的诸因素进行了实验研究。结果表明，不熔化处理使沥青纤维碳氧基团含量增大，形成碳氧网络，使纤维熔点提高，强度上升。不熔化温度，时间，氧化剂深度及升温速率是不熔化处理的主要影响因素，它们影响不熔化纤维的结构与性能，影响沥青繁华纤维的碳化和活化。     

中间相沥青碳纤维裂纹分析

采用扫描电子显微镜等仪器分析了中间相沥青初生纤维、不熔化纤维及碳化纤维的表面形态结构以及裂纹对碳化纤维力学性能的影响,探讨了中间相沥青经纺丝,不熔化处理及碳化处理过程产生裂纹缺陷的因素。     

氧化沥青化学结构及成焦行为的研究

无喹啉不溶物煤焦油在300℃空气吹扫氧化2h-12h制备了一系列氧化沥青,氧化沥青的化学结构通过^1H-NMR,^13C-NMR,FT-IR,元素分析和族组成分析进行,结果表明：空气吹扫可促进脱氢缩合反应的进行,随着空气吹扫时间的增加,α－氢显著减少,氧化沥青中氧含量并没有大的增加。在480℃,0.1MPa和1.6MPa下分别将氧化沥青进行焦化,考察了焦收率以及光学组织结构变化情况。结果表明,空气吹扫氧化可提高煤焦油沥青的焦收率,轻度氧化对中间相组织影响不大,重度氧化抑制中间相组织的发展。     

萘系中间相沥青分子结构对其炭纤维性能的影响（英文）

中间相沥青基炭纤维因具有高模量、低电阻率、高导热等特性，在许多领域有广阔的应用前景。本文分别以采用HF/BF₃催化萘一步法制备的中间相沥青(AR-MP)和采用AlCl₃催化萘两步法制备的中间相沥青(N-MP)为原料，制备了高性能炭纤维。通过元素分析、TG-MS、FT-IR、¹³C-NMR、MALDI-TOF-MS、XRD和SEM等手段对上述沥青和纤维进行了分析表征，对比了不同催化聚合工艺制备的中间相沥青的分子结构和性能，并进一步探究了中间相沥青分子结构差异对其炭纤维结构和性能的影响。结果表明：AR-MP分子构型偏向于半刚性的棒状，含有更多的环烷结构和甲基侧链，其预氧化后的纤维显示出更好的碳平面取向，使其石墨化纤维具有更好的热导率(716 W/m·K)；而N-MP分子构型偏向于刚性的圆盘状、芳香度高，其纤维在后续热处理过程中产生的缺陷更少，石墨化后具有更大的拉伸强度(3.47 GPa)。     

KTN凝胶热处理过程中的反应机理研究

本文研究了Ｓｏｌ－Ｇｅｌ法制备的ＫＴａ０．６５Ｎｂ０．３５Ｏ３（ＫＴＮ）凝胶在热处理过程中的反应机理，发现钙钛矿结构的ＫＴＮ由四步反应生成：５４２℃生成Ｋ３Ｔａ５Ｏ１４．５Ｈ２Ｏ，５９３℃生成Ｋ５Ｎｂ２Ｏ６（Ｏ，ＯＨ）．ｎＨ２Ｏ（α０＝１０．５８Ａ），此两相为立方烧绿石结构，６２０℃未经中间相直接生成ＫＴＮ，６８０℃两种烧绿石结构反应生成ＫＴＮ。     

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 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.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.     

Early ironwork in Biscay: Survey,excavation, experimentation and materials characterization. An integral study of the mountainside ironworks (ferrerías de monte or “haizeolak”)

ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.     

Mechanism Study on the Wear of CrAlTiN Coated High-Speed Steel Twist Drills Under Dry Cutting Conditions

As demands about environment protection are growing up, dry cutting technology is getting more and more concerns from all over the world. Main works performed here are study on dry cutting performances and wear mechanisms of M2high-speed steel (HSS) twist drills with CrAlTiN multicomponent coatings, which was deposited using magnetron sputter ion plating system, in drilling 45 and 30CrMnSiA steel, and their comparisons to those in drilling the same steel but using monolayer CrN and commercial TiN coated drills. Drilling performances of drills are evaluated mainly through the measurements of width on outer corner flank land and the cutting forces. Results show that performances of CrAlTiN coated drills are better than those of monolayer CrN and TiN coated drills. In drilling 45 and 30CrMnSiA steel, the average tool life of the CrAlTiN coated drills are 17.2 and 11.8 times higher than those of the uncoated drills. Observing wear of the drill with scanning electronic microscope, results show that there is no crack or spallation of the CrAlTiN coatings in wear zones. Main mechanism of the wear here is adhesion.     

Study on Bond Ability of Arc-Spraying Coatings with Different Surface Pretreatment on Cast-Iron

Arc spraying coatings are widely used in various applications, but uncommon in cast iron substrate. Different surface pretreatment technology is tested on substrates of gray cast iron. Surface roughness and residual stress were measured by TR200 and X-ray diffraction analyzer. Influence of different surface pretreatment methods ( dry blasting and fusebond) on roughness and residual stress was analyzed. The arc-sprayed coatings of wire 3Cr13 (φ2mm) on gray cast iron substrate is studied. The microstructure and interface of bonding layer were observed by SEM. The bond strength was taken by tensile test. Results show that bond strength with grit blasting is higher than fuse-bond; it is feasible to make wire 3Cr13 coating with arc spraying on cast iron substrate roughened by grit blasting.     

Structural Characteristics of TiO2 Ceramic Coating by Micro-Plasma Oxidation

TiO2 ceramic coatings with thickness of 20 μm were formed on the surface of pure titanium by micro-plasma oxidation. Their micro-structures were investigated by by using X-ray diffraction and their surface images were detected by using scan electronic microscope. There were three kinds of TiO2 coatings, pure anatase type TiO2 phase, mixed phases consisted of rutile type TiO2 phase and anatase type TiO2 phase, pure rutile type TiO2 phase. The coating surface with the pure anatase type TiO2 phase is rough, while the coating surface with the pure rutile type TiO2phase is smooth. The upper coating surface with the mixed type TiO2 phases is anatase type TiO2 structure and the subsurface of the TiO2 coating is rutile type TiO2structure.     

Evaluation of fatigue life of steel using steel grain size

The insightful discussion of the relationship between the construction of metallographic and fatigue life and proposition of mathematical relationships describing this relationship was conducted in the paper. This paper presents a method for estimating the fatigue life, based on the construction of the microstructural material taking into account the grain size and the participation of ferrite and pearlite phase.