分叉纳米碳管与直纳米碳管拉伸力学特性的分子动力学研究

采用分子动力学方法，模拟了分叉纳米碳管与直纳米碳管的拉伸过程，对比、分析了分叉纳米碳管与直纳米碳管的拉伸力学性能。研究表明，分叉纳米碳管拉伸时的屈服与断裂发生在其粗管与细管过渡处，其抗拉强度与韧性分别低于直纳米碳管24％和17％，然而，其弹性模量却与直纳米碳管相当。     

化学气相沉积法快速生长定向纳米碳管

利用化学气相沉积法，采用二甲苯为碳源，二茂铁为催化剂，氮气作保护气，在石英基底上催化裂解生长定向纳米碳管，试验结果表明：在775℃，120min的条件下，可生长出长达200μm厚的定向纳米碳管薄膜；在775℃，反应时间为60min～120min时，纳米碳管的长度为100μm～200μm，而纳米碳管的直径变化不明显。而无氢气，较高的反应温度和连续的催化剂供给对快速生长定向纳米碳管有重要的影响。     

纳米碳管与活性炭复合电极电吸附脱盐性能的研究

为考察纳米碳管（CNTs）、活性炭（AC）及其复合电极的电吸附脱盐性能，将其粉末压制成电极，组装成脱盐器，比较电极电吸附脱盐能力和脱盐能耗。结果表明，在活性炭电极中添加纳米碳管有效地降低了电极电阻和脱盐能耗，少量纳米碳管的添加能在一定程度上提高其电极比表面积、孔容以及在盐水中的比电容；当复合电极中纳米碳管的含量为10％时，其电极在盐水中的电吸附比电容达到113.5F/g，其电极脱盐效果最为显著，其脱盐耗能比活性炭电极降低约67％左右。     

Raymor纳米球形钛粉末产品进军亚洲市场

全球领先的单壁纳米碳管（single—walled carbon nanotubes）和纳米及先进材料制造商Raymor工业公司日前宣布，公司将为其单壁纳米碳管产品（C—SWNT）和球形钛粉末在亚洲地区开发新的市场。之前RaYmOr公司参加了在日本举行型的“nanotech2007”纳米技术2007展会和其他一些重要的纳米技术博览会，     

螺旋形碳纳米管的制备表征及其生长机理的探讨

采用气凝胶与干凝胶两种催化剂载体通过化学气相淀积方法制备出螺旋状的碳纳米管.研究结果表明:气凝胶催化剂载体所制备出的螺旋碳纳米管和干凝胶载体所制备出的螺旋碳管相比较具有以下几个特点:(1)较好的石墨化程度,(2)较小的直径,(3)较好的螺旋形态,即较好的螺距一致性.分析结果认为气凝胶独特的介孔性质是导致气凝胶样品所制备的碳管具有以上特点的根本原因.另外,还提出催化剂颗粒周边上催化活性的各向异性将导致螺旋碳管的生长.     

纳米碳管储氢机理的电化学研究

对流动催化剂法制备的平均直径为6nm的多壁纲米碳管（Multi-walled carbon nanotubes,MWNTs)进行纯化处理，提纯后的多壁纳米碳管利用透射电镜（TEM）表征和电化学储氢研究。同时对该纳米碳管电极进行了自放电实验。结果表明：多壁纳米碳管具有奶高的电化学储氢容量（739mAh/g），但氢与多壁纳米碳管之间的作用力很微弱，氢很容易从多壁纳米碳管中逃逸出。另外，通过对多壁纳米碳管的气相储氢性能的测试，根据实验结果推测；纳米碳管电化学储氢和气相储氢的主要吸附机理相同，即都是物理吸附。     

纳米碳管／聚酰亚胺复合材料制备与性能研究

利用纳米碳管的N甲基吡咯烷酮分散液，通过改变纳米碳管表面的性质和薄膜的制备条件，成功地制备了一系列均匀的纳米碳管，聚酰亚胺薄膜。研究结果表明，添加酰氯化后的纳米碳管到聚酰亚胺中可以改善聚酰亚胺的拉伸性能，而对聚酰亚胺的热稳定性和光学性质没有明显的影响。当添加1．0％的纳米碳管时，与纯PI相比复合材料的弹性模量增加了25．6％，拉伸强度增加了31．0％，断裂伸长率增加了7．6％。     

纳米碳管在聚合物中的应用及其复合材料研究进展

介绍了纳米碳管的制备、表面改性等，论述了纳米碳管在聚合物中的应用及其复合材料的制备方法和研究进展，并总结了存在的主要问题，展望了纳米碳管／聚合物基复合材料的应用前景。     

纳米碳管

纳米碳管 (Carbon nanotube)是 1 991年才被发现的一种碳结构。理想纳米碳管是由碳原子形成的石墨烯片层卷成的无缝、中空的管体。石墨烯的片层一般可以从一层到上百层 ,含有一层石墨烯片层的称为单壁纳米碳管 (Singlewalled carbon nanotube,SWNT) ,多于一层的则称为多壁纳米碳管 (Multi- walled carbon nanotube,MWNT)。SWNT的直径一般为 1 nm～ 6nm,最小直径大约为 0 .5nm,与 C36分子的直径相当 ,但 SWNT的直径大于 6nm以后特别不稳定 ,会发生 SWNT的塌陷 ,长度则可达几百纳米到几个微米。因为 SWNT的最小直径与富勒烯分子类…     

CVD一步法制备纳米碳管的研究

CVD法是制备纳米碳管的重要方法。本文研究了以乙炔为原料气，无需预先还原催化剂，以一定的程序速率从500℃升至750℃一步法生长纳米碳管，直接制备出了管径在8-12nm之间，石墨化程度好的纳米碳管。同时，对升温速率、原料气配比等因素进行了讨论，确定了CVD一步法制备纳米碳管较佳条件范围。     

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.     

Effect of Permeable Crystalline Material on Steel Reinforcement Corrosion of Concrete

Permeable crystalline materialcan permeate into pores and cracks of concrete and catalyze the reaction between Ca(OH) 2and unhydrated cement to generate a great quantity needle non-soluble crystals, which can stop up the pores and cracks of concrete, and increase the impermeability of concrete. This paper reported the results of a study conducted to evaluate steel reinforcement corrosion of concrete specimens uncoated and coated with permeable crystalline material as well as mixed with the permeable crystalline material. The properties evaluated for corrosion test were water impermeability, water absorption, compressive strength and potential. The results of water impermeability, water absorption, compressive strength clearly showed that the permeable crystalline material could prohibit water, any soluble salts and moisture from penetrating the concrete to cause corrosion, leaking, and other problems, and it did increase the compressive strength, which was favorable for protection of corrosion of reinforcing steel. Moreover, it was concluded from the potential-time curve that the steel reinforcement of uncoated specimen was in the state of activation whereas that of other specimens coated and mixed with the permeable crystalline material was in the state of inactivation. Above all, it was indicated that the permeable crystalline materialis very effective to protect the steel reinforcement of concrete from corrosion.     

The Research and Application About "Dry Peeling Off" Technology for Airplane Surface Paint Layer

In this paper, the principle of spurting take off lacquer were introduced; and with orthogonal method the unsaturate polyester was prepared ;it was easy to peel airplane paint layer off with this material and equipment.     

Quality Study of Honeycomb Core Shaping Without Wax Stabilization

Sandwich panels utilizing honeycomb cores result in lightweight, high-strength units that are very rigid. Indeed, they give honeycomb panels the best strength-to-weight ratio of any construction type available. Conventionally, the wax is poured into the cell of the core to strengthen the structure and prevent the core from being crushed during milling. Much time and labor is required to wax, mill, and clean the cores. In this study, the process of pouring wax into the core was skipped. In other words, the cutter directly milled the core. Experiments showed that the compressive strength of the core produced without wax stabilization was only 3% lower than that of cores produced using the traditional method. In addition, the drum peel strengths of cores produced without wax stabilization were 38.4% higher than cores produced using the traditional method, in which residual wax seriously polluted the adhesive. It was also found that eliminating the wax process can reduce costs.     

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.     

In-process thermal treatment of polylactic acid in fused deposition modelling

Polylactic acid (PLA) is one of the most widely used open source fused filament fabrication materials due to its ease of extrusion, biodegradability, and mechanical strength. The mechanical strength of PLA largely depends on the proper growth of its semi-crystalline structure, which can be severely impaired by a low rate of crystallization, particularly in open source printers. This can be further aggravated by the non-uniform thermal distribution of heat that causes improper curing among the extruded beads of the printing material. As a result, PLA printed on open source printers does not achieve the best mechanical properties. This research, for the first time, proposes an additive-free solution implemented through a detailed set of experimentation to improve the curing rate through in-process temperature variations to cure the joints among the beads. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy is used to confirm the improvements in the bead joints. This work is conducted in two phases of experiments. In the first phase, a full factorial ANOVA is used to investigate various process parameters and the important variables are used in the second phase to print test specimens in four different sets.     

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.