中孔活性碳纤维的研究

活性碳纤维具有比表面积大，微孔分布窄，吸附容量大，吸附脱速度快等特点，但一般活性碳纤维属于微孔型，不能吸附大分子物质，使其应用受到限制。近年来，中孔活性碳纤维的研究拓宽了其应用领域。综述了中孔活性碳纤维的国内外研究进展，着重介绍了活化工艺法、金属催化法、非金属添加剂法等制备方法。     

活性碳纤维的表面改性及其对Ag^＋的还原吸附

研究了改性活性碳纤维的物理性质和表面化学性质, 并研究了这些改性后的活性碳纤维的结构及其对银离子的吸附特征。水蒸汽活化所得活性碳纤维分别经Ｈ２Ｏ２、ＫＭｎＯ４、ＨＮＯ３ 或ＮＨ３·Ｈ２Ｏ等多种无机试剂后处理。改性活性碳纤维的孔结构和表面积通过７７Ｋ氮吸附等温线进行表征; 表面化学性质用ＸＰＳ和ＩＲ进行表征。研究结果表明,与原活性碳纤维相比,改性活性碳纤维的比表面积和孔体积下降１０％ － ２０％ 左右。氧化改性较为剧烈的情况下（用浓硝酸处理）, 比表面积和孔体积约降低４０％ 。改性后活性碳纤维表面含氧量及含氧基团的种类与未改性处理的原活性碳纤维也有所区别。这些活性碳纤维对酸性条件下的Ａｇ＋ 的还原吸附量都不高。然而, 改性活性碳纤维对碱性条件下的Ａｇ（ＮＨ３）２＋ 的还原吸附量却大幅度提高,可达５５０ｍ ｇ Ａｇ／ｇ Ｃ以上。推断表面改性在活性碳纤维表面创造了更多有利于碱性条件下发生氧化还原的活性点     

载贵金属活性碳纤维对氙吸附性能的研究

利用活性炭纤维的氧化还原特性,在活性炭纤维上负载了一定量的贵金属银或金。表征了负载贵金属后活性炭纤维的孔结构变化,以及活性炭纤维表面贵金属颗粒的分布和表面化学性质。研究并比较了负载贵金属后活性炭纤维对氙的吸附性能。研究结果表明,在活性炭纤维上负载适量的贵金属银或金,可以显著地提高活性炭纤维对氙的吸附容量,其可能的原因是由于这些贵金属对活性炭纤维孔宽和表面化学性质的修饰,以及提高了活性炭纤维对氙的吸附势。     

新型功能纤维的研制及其对贵金属的回收

活性碳纤维是一种高效吸附新型功能材料,具有巨大的比表面积、均匀的微孔和丰富的表面基团,以及大的吸附容量和吸附速率,已被广泛应用于气体净化、废水处理中。我们于70年代率先在国内开展了活性碳纤维的研究,80年代首先发现了其氧化还原特性,开拓了活性碳纤维提取贵金属方面的应用。活性碳纤维吸附提取贵金属具有可以吸附很低浓度的金银离子、选择性高、其它金属离子影响小、环境污染小等优点,有广泛的应用前景。 本项目在原有工作基础上研制开发新型活性碳纤维,探索提高这些新型功能纤维还原能力、实现功能纤维还原提取回收金     

磷酸活化棕榈纤维的制备与结构表征

为高值化利用棕榈纤维,在不同活化温度下以磷酸为活化剂制备棕榈活性碳纤维,通过扫描电镜、氮气吸附-脱附、压汞法和亚甲基蓝吸附法对其孔隙结构和吸附性能表征,结果表明:(1)随着活化温度升高,棕榈纤维表面受活化剂侵蚀而引起组织结构破坏,产率逐渐降低;(2)随着活化温度升高,活性碳纤维中孔含量减少,有利于微孔的产生,导致比表面积的增加;随着活化温度继续增加,部分微孔扩大为中孔,引起中孔增多;(3)棕榈纤维的亚甲基蓝吸附能力较活化处理前有明显提高,并与活性碳纤维中孔含量变化呈正相关。     

大孔活性碳纤维的初探

活性碳纤维的孔大小和结构对于被吸附物质的分子大小起着决定作用。使用常规方法只能获得孔宽度小于 2nm的微孔活性活性碳纤维 ,近年来采用一些特殊方法也只能获得中孔型。本实验采用高膨润度值的粘胶纤维 ,在国内首次制得了表面具有大孔分布的大孔活性碳纤维 ,以浓度为4 0g/L的磷酸三铵溶液浸泡 ,获得的活性碳纤维表面大孔覆盖率达 3个 / μm2 ,其大孔主要分布在 5 0～2 0 0nm之间     

两种超细活性碳纤维的制备及其甲醛吸附性能

以超细预氧化纤维毡为原料,采用电加热和微波加热方法制备两种超细活性碳纤维吸附剂(UFACF-1、UFACF-2),在相同湿度条件下,对两种超细活性碳纤维的甲醛吸附性能进行测定;采用场发射扫描电镜、傅里叶变换红外-拉曼光谱仪、全自动比表面和孔径分布分析仪对两种超细活性碳纤维吸附剂的纤维形态、结构、比表面积、孔容和孔径分布进行表征;两种超细活性碳纤维在纤维形态、结构和甲醛吸附性能上均有差别,其中,UFACF-1比表面积为805.25m2·g-1,总孔容为0.366cm3·g-1,UFACF-2比表面积为733.32m2·g-1,总孔容为0.386cm3·g-1,UFACF-1甲醛吸附性能优于UFACF-2;UFACF-1含有大量极微孔和含氧官能团,对于室内甲醛处理,是一种有应用潜力的新型吸附材料。     

具有不同孔结构的沥青基球状活性炭对肌酐及维生素B12吸附性能？…

主要研究了３种具有不同孔结构的沥青基球状活性炭对肌酐及ＶＢ１２的吸附性能,与ＢＥＴ比表面主孔结构进行了关联。结果表明,具有微孔结构的沥青基球状活性炭对小分子肌酐的吸附性能较好;具有中孔结构的沥青基球状活性炭对中分子物质ＶＢ１２具有较好的吸附性能;而中孔与微孔并存的沥青基球状活性炭对肌酐及ＶＢ１２都有较好的吸附性能。     

不同碳源多孔碳纤维制备及其吸附性能

先用静电纺丝法制备聚丙烯腈(PAN)、聚乙烯醇(PVA)和聚乙烯吡咯烷酮(PVP)基高分子纤维,然后将其碳化制备出不同碳源的多孔碳纤维材料。使用X-射线衍射仪、红外光谱仪、差示扫描量热仪和N₂吸脱附分析仪等手段表征了碳纤维材料的结构和性能。结果表明,PAN基碳纤维的比表面积最大(113.5 m²/g)、微孔较多,对刚果红的吸附量最大(560.2 g/kg)。根据吸附动力学模型和吸附等温线的分析结果,碳纤维对刚果红的吸附属单层吸附。结果还表明,温度越高材料的吸附速率越高但是吸附量没有明显的变化;在酸性条件下PVA基碳纤维保持较高的吸附活性,而PAN基碳纤维则与之相反;刚果红水溶液的pH值对PVP基碳纤维吸附活性的影响很小。     

PAN基ACF的孔结构表征

通过在７７．４Ｋ下的Ｎ２吸附对连续化工制备的聚丙烯腈基活性碳纤维孔结构进行了考察,采用 Ｄｕｂｉｎｉｎ－Ｒａｄｕｓｈｋｅｖｉｃｈ方程,Ｈｏｒｖａｔｈ－Ｋａｗａｚｏｅ方程及密度函数理论对其孔结构参数诸如此表面积,微孔表面积,孔容及孔径分布者表征。     

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.