静电纺丝纳米纤维的应用进展

近年来静电纺丝技术在制备纳米纤维领域得到了广泛应用,被认为是制备纳米纤维最简单有效的方法之一。通过静电纺丝法制备的纳米纤维具有长径比大、孔隙率高、比表面积大等优点,在过滤材料、生物医学、传感器以及其他特殊领域都有着良好的应用前景。主要介绍了近几年来国内外静电纺丝纤维在过滤吸附膜、生物医学、传感器、防护应用及其他一些特殊领域中的研究现状,并展望了静电纺丝纳米纤维的发展趋势和研究方向。     

静电纺丝法制备氧化物纳米纤维及其气敏特性

静电纺丝技术由于简单的装置和制备过程,以及所使用材料的多样和应用领域的广泛,被认为是制备纳米纤维材料最具发展潜力的方法.简述了静电纺丝技术和影响纺丝质量的相关因素;介绍了静电纺丝制备半导体氧化物纳米纤维的方法及纳米纤维在气体传感器领域的应用;比较了几种纳米纤维和纳米线纳米棒等气敏元件的敏感特性;最后分析了纳米纤维具有优...     

静电纺丝技术在超级电容器中的应用

静电纺丝是一种新型的非纺织成丝技术,具有适用材料体系广泛、纤维尺寸结构可控、工艺简便等特点,是制备连续纳米纤维的重要方法.静电纺丝技术制备的纳米纤维薄膜因具有巨大的纳米表面和网状孔隙结构可调等优势,在超级电容器领域显示出诱人的应用前景.综述了近年来静电纺丝技术在超级电容器电极材料和隔膜材料方面的研究进展,介绍了碳基、金属氧化物和聚合物电极材料高活性纳米纤维的制备方法及电化学行为,以及静电纺丝无纺布作为隔膜材料显示出的巨大优势,并总结了制约静电纺丝走向商业化的不利因素,如产率低、薄膜强度不足、喷丝不稳定等,最后介绍了近年来静电纺丝技术在结构可控、规模化制备的产业进展,并展望了其在超级电容器领域中的商业化应用前景.     

静电纺丝制备生物基食品活性包装纤维膜及其应用

目的 将具有电纺性的生物基材料应用在食品包装领域,为静电纺丝技术在食品活性包装纤维膜制备中的应用提供参考和依据.方法 对静电纺丝技术的原理、优势进行分析,归纳蛋白质、多糖等生物基大分子材料的可纺性、由不同材料复合制得纳米纤维膜的特性和功能差异,以及静电纺丝技术制备生物基食品活性包装纤维膜及其在抗菌、抗氧化、功能吸收包装等方面的应用,并对该技术在食品活性包装中存在的问题和发展前景进行展望.结果 静电纺生物基纳米纤维膜可用作食品活性包装,具有良好的贮存与保鲜效果.结论 静电纺丝具有工艺简单、成本较低等优点,且制得的纳米纤维膜比表面积大、纳米尺度效应明显,已成为一种非常便捷的制备功能活性食品包装材料的微纳制造技术;再结合生物基大分子材料在安全、无毒、可降解、可食用等方面的优势,其在食品包装领域具有良好的发展前景.     

静电纺技术在耐高温纤维材料领域研究进展

耐高温纤维在高温过滤膜、锂电池隔膜以及高温催化等方面有着良好的应用。结合纳米纤维高孔隙率、高比表面积等优点,将这些纤维原料经过静电纺丝技术制备成纳米纤维,应用于工业、国防、医疗、环境保护等领域已成为当今材料科学的研究热点。重点综述了静电纺丝技术制备耐高温性能纳米纤维材料的研究进展,如静电纺芳纶、聚酰亚胺、聚苯并咪唑、含氟高分子等聚合物纳米纤维及陶瓷无机纳米纤维等,为进一步开展静电纺丝制备耐高温纳米纤维的研究和应用提供参考。     

静电纺丝纤维力学性能提升方法及应用研究进展

静电纺丝技术是制备一维材料最有效的方法之一，其操作简便且成本低廉。可制备具有多种成分、结构和性能的纳米纤维。但由于纤维内部组分取向性差、界面相互作用弱以及纤维之间接触微弱等因素导致静电纺丝纳米纤维力学性能普遍较弱，限制了其在很多领域的应用。近年来，研究工作者主要从增强单根纤维或纤维集的力学性能出发，发展了如纳米填充、交叉点焊接等有效提升纤维力学性能的方法。首先概述了静电纺丝纤维力学性能提升方法，并对强韧化机理、提升效果进行综述和总结。随后通过代表性的例子讨论了电纺纳米纤维的典型应用，包括分离过滤、电化学储能以及生物医学。最后对影响微纳米纤维膜力学性能的因素以及进一步提升力学性能的方法等方面进行分析和展望。     

聚合物静电纺丝技术在催化材料制备中的应用研究进展

聚合物在溶液中或熔融状态下利用静电纺丝技术可以制备连续的纳米纤维。利用溶胶转化法、同轴电纺法、功能复合法等静电纺丝制备技术和后处理方法可以容易地实现多种催化剂在纳米尺寸上的掺杂和共混,制备纤维膜复合材料。纳米纤维催化复合材料具有催化活性高、稳定性好、协同效应明显等优点。文中对高压静电纺丝技术及其在催化材料中的应用国内外的研究进行综述。     

静电射流技术制备纳米材料的研究进展

电流体动力学射流技术包括静电喷雾和静电纺丝2项孪生技术,是新型的纳米材料制备方法,可以制备纳米薄膜、纳米纤维、壳一鞘结构纤维、纳米管、微纳米包囊、量子点等各种形态的纳米材料.对此进行了系统的总结:静电喷雾技术制备的薄膜比常规喷雾法制备的薄膜更为均匀;静电纺丝技术近年来更是在取向型纤维的制备、无机陶瓷纤维的制备以及同轴射流技术方面取得了重大突破.     

静电纺丝法制备PLA/rGO纳米纤维膜及其在油水分离中的应用

使用改进的hummers法制备了氧化石墨烯,并用抗坏血酸还原了氧化石墨烯制备了具有疏水性能的rGO.使用静电纺丝的方法制备了PLA/rGO纳米纤维膜,探究了rGO的加量对PLA纳米纤维膜疏水性的影响.PLA/rGO纳米纤维膜的红外光谱与拉曼光谱图表明PLA与rGO为物理混合,在静电纺丝的过程中没有发生化学变化.研究发现...     

醋酸纤维素纳米纤维的制备及应用进展

静电纺丝技术可制备聚合物纳米纤维。由于纳米纤维特有的表面效应、小尺寸效应及量子尺寸效应等特点,在各领域的应用受到广泛重视。醋酸纤维素作为一种重要的纤维素衍生物,在塑料、化纤工业中应用比较普遍,近年来采用静电纺丝技术制备醋酸纤维素纳米纤维的研究成果逐渐增多。笔者综述了采用静电纺丝方法制备醋酸纤维素纳米纤维的技术进展情况,以及醋酸纤维素纳米纤维的应用进展,同时对纤维素衍生物纳米纤维的制备方法与应用进行了展望,以期进一步扩大醋酸纤维素的应用领域。     

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.     

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 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.     

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.……     

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.