一维纳米材料的研究进展

对一维纳米结构的研究进展进行了综述。阐述了一维纳米结构如纳米管、纳米棒、纳米线和纳米带的制备方法，其中包括气相化学合成法、热分解前驱体法、模板法、电弧等离子体等方法，总结了一维纳米材料的表征和各种生长机理以及在物理、化学、机械、材料等领域的应用。简单介绍了采用热分解法制备二硫化钨纳米纤维。     

一维金属纳米材料的制备技术

一维金属纳米材料很好地集合了一维纳米结构材料和金属的特性，在光学、电学、磁学等领域有着不可忽视的潜在应用前景，且一维金属纳米材料的成功制备对于顺利实现纳米尺度功能组件的实用化意义重大。该文作者综述了一维金属纳米材料（纳米线、纳米棒、纳水管）的最新制备进展，重点评述了模板合成法、台阶边缘修饰法、介孔层状结构替曲法、软溶液法制备一维金属纳米材料的过程及生长机理，分析了目前研究上存在的问题，同时展望了未来的发展趋势。     

一维SiC纳米材料制备技术研究进展

一维SiC纳米材料由于具有独特的电学、光学及力学性能,在新型纳米光电子器件、生物医学传感器、储能和材料增韧等领域拥有广阔的应用前景。介绍了基于气相-液相-固相(VLS)、固相-液相-固相(SLS)、气相-固相(VS)和氧化物辅助生长的生长机制(OAG)制备一维SiC纳米材料的方法,并分析了各种方法的特点。一维SiC纳米材料的制备方法主要存在以下几个问题:(1)工艺过程中温度高(模板法、激光烧蚀法、电弧放电法、热蒸发法、碳热还原法)或压力大(溶剂热法),涉及过程复杂;(2)产物中常含有金属杂质(如金属气-液-固(VLS)催化生长法)或表面包覆SiO2层(激光烧蚀法、电弧放电法、碳热还原法),形貌不均一;(3)产量低(模板法、溶剂热法)。这些问题制约了高纯一维SiC纳米材料的制备及其本征性能的研究,也不利于实现一维SiC纳米材料的规模化生产。因此,发展新型低成本高纯一维SiC纳米材料的制备技术对于推动一维SiC纳米材料的研究、规模化生产以及在相关高科技领域中的应用具有十分重要的意义。     

水热法及溶剂热合成法制备Ⅳ族一维无机纳米材料

一维纳米材料由于具有优异性能成为了近年的研究热点之一，水热法及溶剂热合成法是近年来发展起来的合成一维纳米材料的有效方法。评述了近年来这两种方法在合成Ⅳ族一维无机纳米材料方面的研究现状与最新进展，重点介绍了水热法合成碳纳米管和纳米丝以及溶剂热合成法合成硅、锗纳米线等一维无机纳米材料的进展情况。最后比较了这两种方法的优缺点并对其发展作了展望。     

纳米结构Fe_3O_4制备与应用的研究进展

纳米结构的Fe3O4具有与生物组织的相容性以及与尺寸和形貌有关的电学和磁学性能,在磁流体、传感器和生物医药等领域具有广泛的应用前景。Fe3O4纳米结构的主要制备方法包括高温气相法、高温有机液相回流法、溶剂热法和水热法等;已经制备出各种纳米结构单元的Fe3O4,如:零维纳米颗粒,纳米颗粒组装的纳米链,纳米颗粒组装的微球,一维纳米线、棒,二维纳米片,以及三维的金字塔、八面体、核桃状球形纳米颗粒等。该文综合介绍这些制备方法的特点及其近期的研究进展,并对Fe3O4纳米结构的性质和应用进行综述。最后对Fe3O4纳米材料未来的发展进行展望。     

一维钴纳米材料的化学制备及磁学应用

一维钴纳米材料因其磁性能良好、居里温度高等特点,为制备非稀土基永磁材料提供了可能。介绍了一维钴纳米材料的研究进展和磁学应用现状,对一维钴纳米材料在化学制备方法、微观结构、磁学应用前景等方面进行了分析。一维钴纳米材料的化学制备方法较多,包括化学还原法、金属有机前驱体热解法、模板法等,且不同化学方法各具其特点,适用于不同长径比的一维钴纳米材料的制备。着重介绍了几种常用的化学制备方法,并针对一维钴纳米材料所具备的高磁晶各向异性和形状各向异性带来的高矫顽力(H_c)、高饱和磁化强度(M_s)、高剩余磁化强度(B_r),以及高最大磁能积((BH)_(max))等优点,总结了其在永磁材料、高密度磁存储等磁学领域的应用具有重要的研究前景和研究意义。     

一维硅纳米线研究进展

一维纳米结构材料主要以硅纳米线以及硅纳米管为主，而硅纳米线作为一维硅纳米材料的典型代表，不仅具有半导体所有特殊性质，还展现出不同于普通硅材料的场发射、热导率及可见光致发光等物理性质，在众多热门方面如纳米电子器件、光电子器件，尤其是新能源领域-作为锂离子电池(LIBs)的负极材料目前引起世界的广泛关注，因为其一维几何形状适应了循环过程中硅的大体积变化，并能在所有操作阶段易于电子传递，因此具有巨大的潜在应用价值，成为当今世界科学研究领域的热点和前沿。然而纳米线的大规模可控制备依然是个难题。本文介绍了一维硅纳米线结构的制备、合成方法以及作为硅负极电化学性能的研究进展，并对储锂性能提升机制进行了探讨。     

纳米材料在金属离子分析中的应用

纳米材料的特殊结构使其具有奇异的光、电、磁、热性能。目前,该材料在陶瓷、金属、聚合物纳米粒子、纳米结构合金、着色剂与化妆品,电子原件的制备,金属元素的分析等方面有广泛应用。本文分析了纳米材料在国内外的发展现状,综述了其制备方法、吸附金属离子的原理和应用,重点讨论纳米氧化物、纳米管、纳米线、纳米棒、杂化纳米材料以及分子印迹微纳米材料在金属离子分析方面的应用,并对其发展前景做了展望。     

一维氧化钼纳米材料的研究进展

一维氧化钼纳米材料具有优异的电学性能、电化学性能、场发射性能和气敏性能,在催化剂、传感器、平板显示器、智能窗、电池电极等领域显示了广阔的应用前景;其主要制备方法有水热法、气相沉积法和模板法.该文在综述了一维氧化钼纳米材料的制备方法、性能及应用的研究进展之后,指出了当前制备方法中存在的问题,并展望今后的研究重点是如何将一维氧化钼纳米材料应用于实际.     

浅谈纳米氧化铝的研制及应用

纳米材料是指晶粒度为纳米级的多晶材料，被科学家誉为“21世纪最有前途的材料”。由于纳米氧化铝所具有的体积，表面界面，量子尺寸，以及宏观隧道等效应，使其在力、热、光、电、磁、催化等方面显示独特的性能，因而具有广阔的前景。介绍了纳米氧化铝的三大制备方法：固相法、气相法、液相法的优缺点及纳米氧化铝的应用。     

GaN 纳米结构的制备

提出一种通过对溅射Ga2O3薄膜后氮化技术制备GaN纳米结构的方法，已成功地制备出CaN纳米线、纳米棒和纳米带。该方法既不需要催化剂，也不需要模板限制，不仅避免了杂质污染，而且简化了纳米结构的制造工艺，对于纳米结构的应用非常有利。利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)和选区电子衍射(sAD)研究了CaN纳米结构的形貌和晶格结构。结果表明CaN纳米结构是具有六角纤锌矿结构的GaN晶体，不存在Ga2O3或Ga的其他相。研究结果证明在高温氮化过程中由于晶格缺陷的降低和晶化的改进能够得到高质量的GaN晶体。简要地讨论了GaN纳米结构的生长机制。     

Dysprosium cerate nanostructures:facile synthesis,characterization,optical and photocatalytic properties

A facile approach was developed to prepare Dy_2Ce_2O_7 nanostructures. Dy_2Ce_2O_7 nanostructures were prepared by applying cerium(IV) ammonium nitrate and dysprosium nitrate as Ce and Dy precursors. It was found that the kind of connecting agent, space-filling template and chelating agent were significant factors for the control in shape and size. Transmission electron microscopy(TEM), X-ray diffraction(XRD), diffuse reflectance UV-vis spectroscopy(DR-UV-vis), field emission scanning electron microscopy(FESEM), photoluminescence spectroscopy(PL) and energy dispersive X-ray microanalysis(EDX) techniques were applied to characterize the Dy_2Ce_2O_7 nanostructures and investigate their optical characteristics. To examine the photocatalytic activity of as-produced Dy_2Ce_2O_7 nanostructures, the photocatalytic degradation of erythrosine dye as water pollutant was carried out. The results of the photocatalytic investigations suggest as-obtained nano-sized Dy_2Ce_2O_7 product as a new, proper and efficient candidate for photocatalytic usages under UV illumination.     

溶胶-凝胶法制备金银合金纳米线阵列

金银纳米材料因其纳米尺度而在光电等方面有许多优良的性质和用途, 若将两者混合可大大改善其性能. 为此, 利用阳极氧化法制备出氧化铝模板, 并用自制的模板结合溶胶凝胶法成功地制备了金银合金纳米线. 扫描电镜照片显示氧化铝模板具有比较直的孔道和高的孔洞率, 金银合金纳米线由于模板的限制作用而呈现出高度的有序性. 透射电镜照片显示单根纳米线长而光滑, 选区电子衍射显示纳米线具有多晶结构, 能谱分析表明纳米线是由金和银两种元素组成. 文中对合金纳米线的形成原因和影响因素都做了简单的分析.     

不同工艺制备的氟化镁材料对真空镀膜的影响

用三种不同工艺制得的氟化镁为镀膜材料，考察了不同材料的结构对镀膜工艺和薄膜光学性能折射率的影响，并就其影响的原因进行了宏观分析，为选择高质量的镀膜材料提供了理论依据。     

Enhanced visible-light photocatalytic activity of samarium-doped zinc oxide nanostructures

In the present work,we have synthesized samarium doped zinc oxide nanostructures(Zn_(1-x)Sm_xO;x=0.00,0.02,0.04 and 0.06) via chemical precipitation method and studied their structural,morphological,optical and photocatalytic properties.X-ray diffraction(XRD) patterns,PL and Raman spectra results indicate that the undoped and Sm-doped ZnO nanostructures are crystallized in a hexagonal wurtzite structure.FESEM images show that the morphology of the sample changes from cubical to hexagonal nanostructures with increase in Sm~(3+)doping concentration.The EDX spectra confirm the incorporation of Sm~(3+)ion in ZnO.The influence of Sm~(3+)doping on the structure,morphology,absorption,emission and photocatalytic activity of ZnO nanostructures were investigated systematically.The addition of Sm~(3+)ion leads to a red shift in the optical energy band gap from 3.19 to 2.67 eV and hence,increases the visible light absorption ability.The presence of E_2(H) and E_1(LO) modes in microRaman spectra confirms the crystallinity and defects in the samples.The detailed photocatalytic experiments reveal that Sm-doped ZnO nanostructures show the maximum photodegradation efficiency for Methylene blue(MB) dye for x=0.04,i,e.,94.94%,under visible light irradiation.The photocatalytic efficiency improves by 6.98 times when ZnO is doped with rare earth metal ion(Sm~(3+)) and is a potential candidate for practical applications.The investigation demonstrates that as-synthesized nano-sized photocatalysts act as an efficient photocatalyst for the degradation of MB dye.     

Fabrication and characterization of YVO4：Eu^3＋ nanomaterials by the microwave technique

Fabrication and characterization of YVO4:Eu3+ nanophosphors prepared by microwave(MW) irradiation assisted soft template synthesis were reported.The effects of synthesis conditions such as different powers of MW irradiation,pH values and concentration of reac-tion materials on properties of nanophosphor were also investigated to obtain the controllable size,morphology and high luminescence effi-ciency.Morphology,crystalline structure,and optical properties were characterized by field emission scanning elect...     

Effect of Boron and Heat Treatment on Mechanical Properties of White Cast Iron for Mining Application

 Heat treatment methods were applied to white cast iron for improving the impact and wear resistance. Additionally, chemical composition optimization was made. Furthermore, the effect of boron addition on such applications was investigated. Samples were investigated by using optical and electron microscope methods. Hardness, wear and impact tests were conducted. The results showed that the secondary carbides in the standard alloy were iron-enriched, needle-like carbides M3C when the boron-added alloy contained Fe23(C,B)6 type, globular secondary carbides. It was concluded that heat treatment B provided higher wear and hardness properties, compared to the standard heat treatment. Optimum mechanical properties were obtained by lower destabilisation temperatures and increasing temperature reduced the wear resistance and hardness.     

Construction of Customized Mass-Stiffness Pairs Using Templates

This paper is a tutorial exposition of the template approach to the construction of customized mass-stiffness pairs for selected applications in structural dynamics. The exposition focuses on adjusting the mass matrix while a separately provided stiffness matrix is kept fixed. Two well known kinetic-energy discretization methods described in finite-element method (FEM) textbooks since the mid-1960s lead to diagonally lumped and consistent mass matrices, respectively. These two models are sufficient to cover many engineering applications. Occasionally, however, they fall short. The gap can be filled with a more general approach that relies on the use of templates. These are algebraic forms that carry free parameters. This approach is discussed in this paper using one-dimensional structural elements as examples. Templates have the virtue of producing a set of mass matrices that satisfy certain a priori constraint conditions such as symmetry, nonnegativity, invariance, and momentum conservation. In particular, the diagonally lumped and consistent versions can be obtained as instances. Thus those standard models are not excluded. Availability of free parameters, however, allows the mass matrix to be customized to special needs, such as high precision vibration frequencies or minimally dispersive wave propagation. An attractive feature of templates for FEM programming is that only one element implementation as module with free parameters is needed, and need not be recoded when the application problem class changes.