p型含铜透明导电材料的新进展

基于p型透明导体在平面显示、透明二极管和太阳能发电等领域的广泛应用前景, 一些含铜的透明导体材料因具有优异的性能而备受人们关注. 本文综述了p型含铜透明导体的研究现状. 重点介绍含铜的氧化物和氧硫化合物的本征及其掺杂研究进展, 从结构化学的角度论述了此类化合物p型导电的机理及共性. 研究结果表明, 含[Cu₂S₂]导电层的层状氧硫化合物是颇具潜力的p型透明导体候选材料.     

高Tc铋层状压电陶瓷结构与性能

综述了铋层状压电陶瓷的结构特点及性能研究,铋层状压电陶瓷的（Ｂｉ２Ｏ２）＾２＋层和钙钛矿层（Ａｍ－１ＢｍＯ３ｍ＋１）＾２－按一定规则 排列而成,上Ａ为适合于１２配位的离子;Ｂ为适合于八面体配位的离子,ｍ为一整数,其值一般为１￣５,与钛酸钡（ＢａＴｉＯ３）或锆钛酸铅（ＰＺＴ）陶瓷相比,铋层状压电陶瓷具有以下特点：低介电常数、高ＴＣ、机电耦合系数各向异性明显、低老化率、高电阻率等。     

南墅小鳞片石墨的FeCl3层间化合物结构研究

一、前言层间化合物由层状结构物质和夹层剂组成。层状晶体、层间仅借范德华力结合,如克服层间力,使夹层剂插入到层状结构物质的层间空处,而不损害它原有的层状结构键合网络,称为夹层作用。所组成的化合物叫层间化合物,层状物质为宿主,夹层剂为寄主。由于夹层剂的插入,石墨基体层间距离扩大到3.355n+5.8A,n为层间化合物的阶数。X光衍射、高分辩电子显微镜、中子衍射、穆斯堡尔谱及喇曼光谱等给石墨—层间化合物的结构分析提供了广阔天地,发现了金属氯化物—石墨层间化合物的多相结     

新型功能性层状材料的合成及应用

无机层状化合物是一类具有规整层状结构的化合物,其层板上骨架阳离子的可替代性以及层间离子的可交换性引起了研究者的广泛兴趣.通过调变层板骨架阳离子、表面负载活性物种、层间柱撑无机或有机基团合成了各种新型功能性层状材料,并在酸碱催化、光催化、环保以及医药等领域有着广泛的应用.详细介绍了近年来新型层状化合物的合成及应用进展.     

高Tc铋层状压电陶瓷结构与性能

综述了铋层状压电陶瓷的结构特点及性能研究．铋层状压电陶瓷的结构由（Ｂｉ_２Ｏ_２）^２＋层和钙钛矿层（Ａ_ｍ－１Ｂ_ｍＯ_３ｍ＋１）^２－按一定规则共生排列而成．此处 Ａ为适合干 １２配位的离子;Ｂ为适合于八面体配位的离子,ｍ为一整数,其值一般为１～５．与钛酸钡（ＢａＴｉＯ_３）或锆钛酸铅（ＰＺＴ）陶瓷相比,铋层状压电陶瓷具有以下特点：低介电常数、高Ｔ_ｃ、机电耦合系数各向异性明显、低老化率、高电阻率等． 先前研究证明,居里温度不仅与极化原子位移、自发极化强度、Ａ位Ｂｉ含量有关,而且还与取代离子的特性诸如离子半径、电负性、核外电子排布有关．压电活性低是铋层状陶瓷的本质缺点,通常发展该材料的途径为化学取代或晶粒取向技术．研究材料结构与性能之间的关系有助于发展铋层状压电陶瓷材料．     

超级电容器中的二维材料

以石墨烯为代表的具有层状结构的二维材料因具有大比表面积等特性成为超级电容器电极材料的热门候选。文章着眼于针对诸如石墨烯、过渡金属二硫族化合物、过渡金属碳/氮化物、层状过渡金属氧化物/氢氧化物等二维材料在超级电容器领域应用的研究,尝试总结了其制备方法、产物形貌特征以及作为电极的性能等,并对这一领域的未来发展和面临的挑战提出了看法与预测。     

超级电容器中的二维材料

以石墨烯为代表的具有层状结构的二维材料因具有大比表面积等特性成为超级电容器电极材料的热门候选.文章着眼于针对诸如石墨烯、过渡金属二硫族化合物、过渡金属碳/氮化物、层状过渡金属氧化物/氢氧化物等二维材料在超级电容器领域应用的研究,尝试总结了其制备方法、产物形貌特征以及作为电极的性能等,并对这一领域的未来发展和面临的挑战提出了看法与预测.     

单晶Bi纳米带的合成与表征

采用溶剂热方法,以苯乙烯为还原剂和配位剂,合成了宽度为40nm-60nm、长度为600nm-1μm铋纳米带,并对其反应机理进行了探讨。在铋纳米带的合成中,α-铋的层状结构是形成铋纳米带的关键因素。配位试剂在各晶面的吸附对产物的形貌具有重要影响。通过改变配位试剂与铋盐的质量比,可以实现对铋纳米结构和形貌的调控。     

铋层状结构无铅压电陶瓷的研究与进展--无铅压电陶瓷20年发明专利分析之三

铋层状结构无铅压电陶瓷因其居里温度高、介电常数低，介电击穿强度大及各向异性大等特征近年来受到广泛研究。本文归纳和分析了铋层状结构无铅压电陶瓷近20年的发明专利．着重介绍了主要体系的压电铁电性能．并对铋层状结构无铅压电陶瓷今后的发展与研究提出了一些建议。     

二维层状材料麦羟硅钠石的研究进展

二维层状材料硅酸盐是硅、氧与其他化学元素等结合而成的化合物的总称。其以硅氧四面体为基本结构,根据不同的配合形成了各类的硅酸盐,其种类繁多、熔点高、比表面积大、抗蠕变性良好以及可插层,且具有优异的耐腐蚀性、热稳定性和化学稳定性,被广泛应用于化工、建材、耐火材料、陶瓷、造纸、橡胶、塑料、医药、农药、纺织、化妆品、国防和环保等领域。麦羟硅钠石是一种水合硅钠石,它属于层状硅酸盐,结构式为Na_2Si_(14)O_(29)·n H_2O,作为一种新型的层状硅酸盐材料,相比于蒙脱石等其他层状硅酸盐,它的活性Si-OH位于层间的表面上,有利于其功能化改性,且显著提高了层间电荷密度,从而提高了其离子交换能力。麦羟硅钠石具有规整的层板结构和可调控的层间距,可以在层间引入不同功能的分子,作为组装多功能复合材料的基础材料。麦羟硅钠石是纯硅体系,具有很好的生物相容性,单个片层较厚(1.12 nm),结构稳定性好,可以人工合成,通过控制合成工艺,可以得到高纯度的产物,且价格低廉,具有市场竞争优势。到目前为止,麦羟硅钠石的制备主要是通过水热法人工合成,硅源可以为硅藻土、水玻璃、沉淀白炭黑浆料(PPS)、SiO_2-NaOH-Na_2CO_3-H_2O体系、硅胶、正硅酸甲酯、正硅酸乙酯等。随着研究的不断深入,制备方法越来越简单,晶型也越来越完善。麦羟硅钠石的改性研究包括有机插层改性、酸化处理和无机改性。此外,由于聚合物/层状硅酸盐复合材料具有常规聚合物复合材料所没有的结构、形态,以及较常规聚合物复合材料更优异的力学性能、耐热性和气体液体阻隔性能等,麦羟硅钠石/聚合物复合材料也得到了广泛的研究。在应用方面,麦羟硅钠石由于具有较高的离子交换量和较大的比表面积,可以作为吸附材料吸附重金属离子和有机染料等。因其层状结构和较大的比表面积,麦羟硅钠石可以作为硅源合成沸石分子筛,其具有较高的水热稳定性和一定的耐酸性。麦羟硅钠石由于化学稳定性及较强的负载能力,可以有效负载催化材料,并使催化材料获得很好的分散效果,增强其催化性能。为反映当今国内外麦羟硅钠石的研究成果,本文介绍了麦羟硅钠石的结构与性质、制备、改性以及应用等内容。但是目前对于麦羟硅钠石的研究还不够成熟,存在一定的局限性。若将来麦羟硅钠石能够在生产实践中得到应用,其前景将十分广阔。     

Relaxation dynamics,microwave absorption,and secondary periodicity in properties of rare-earth-modified bismuth ferrites

Based on an analysis of the structure and physical properties of bismuth ferrite (BiFeO₃) modified by rare-earth (RE) elements, solid solutions characterized by the presence of spontaneous magnetization, low- and high-temperature relaxation, and maximum microwave absorption have been found. It is established that these materials exhibit a secondary periodicity in their properties. The observed effects are related to the appearance of symmetry phase transitions, specific features of the crystal chemistry of RE elements, and changes in the type of solid solutions.     

Synthesis of acicular α-Bi2O3 microcrystals by microwave-assisted hydrothermal method

ABSTRACT

Materials based on bismuth(III) oxide are candidate to be used in optical and electronic devices because of their properties such as a variable band gap, photoconductivity, photoluminescence, high refractive index, and dielectric permittivity. These properties are dependent of several factors, e.g., present phases and crystal morphology. The microwave-assisted hydrothermal method (MAH) is a fast and efficient approach of synthesis to obtain semiconductor powders. However, the synthesis of monoclinic bismuth oxide (α-Bi₂O₃) with acicular morphology by MAH was not found in literature. In this paper, microcrystals of acicular α-Bi₂O₃ (monophasic) were successfully obtained by MAH using a synthesis temperature of 80°C for 0.5?h. X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron, and transmission electron microscopies showed the formation of a monoclinic structure (space group P21/c) with acicular morphology that grew along the [001] direction. The temperature and time necessary to synthetize acicular microcrystals were significantly lower than those found for acicular microcrystals obtained by conventional hydrothermal method.     

Étude de la structure et des propriétés d'élastorésistance des couches minces de bismuth

We studied the influence of different conditions of preparation on the structure and elastoresistance properties of bismuth thin films.Bismuth films grow mainly with a [0001] fibre axis texture, but in some cases we observed randomly oriented bismuth grains.A suitable thermal treatment appreciably improves the gauge coefficient of thin films. The condensation rate has no marked influence on the structure and elastoresistance properties of the deposits.     

铋含量对钛酸镧铋陶瓷结构和介电性能的影响

通过固相合成的方法制备了Bi3.25,LaxTi3O12（x=0．98～1．03，简称BLT）陶瓷。通过XRD，SEM和阻抗分析仪表征了陶瓷的晶体结构和晶体形貌，测试了陶瓷的介电频谱，结果表明陶瓷的晶体结构为典型的层状钙钛矿结构且不随Bi含量和温度的变化而改变；随着Bi含量的增加晶体形貌由棒状颗粒向片状颗粒转变，而且陶瓷的致密度也得到提高；介电常数随Bi含量的增加先增大后减小，并且在x=1．02时达到最大值。     

Layer type tungsten dichalcogenide compounds: their preparation,structure, properties and uses

Tungsten dichalcogenides constitute a well defined family of compounds which crystallize in a layer type structure. These compounds find a wide range of applications in the field of catalysis and as a lubricant at high temperatures and pressures. They have also been investigated successfully as cathode and anode materials in photoelectrochemical cells for solar energy conversion. The layered tungsten dichalcogenides also exhibit superconducting behaviour when intercalated with alkali or alkaline earth metals and different divalent rare earth metals. In the present paper an attempt has been made to review the preparation, crystal structure and band models of tungsten dichalcogenides. Furthermore, we have tried to incorporate the physical, chemical, optical and electrical properties along with intercalation, thermal stability and uses of these compounds.     

金属氰胺化合物的结构、合成及电化学储能应用

金属氰胺化合物M_x(NCN)_y作为类氧硫族化合物, 是一类新兴的无机功能材料。准线性[NCN]^2-阴离子赋予其空旷和具有孔道的晶体结构、独特的电子结构和新奇的物化性质, 金属氰胺化合物在固态发光、光/电催化及电化学储能等诸多领域展现出应用前景, 近年来逐渐成为研究热点。本文简要回顾了金属氰胺化合物的研究历史, 概述了金属氰胺化合物的晶体结构及物化性质, 总结了常见合成方法及策略, 探讨了金属氰胺化合物在电化学储能领域的应用, 重点论述了其作为锂钠离子电池新型负极材料的电化学性能及存储机制。     

Synthesis of single-crystalline bismuth nanobelts and nanosheets

Single-crystalline bismuth nanobelts have been synthesized successfully by solution-phase route, using ethylene glycol as reductant and solvent. It was speculated that the final morphology resulted from the layered structure of rhombohedral bismuth.     

Influence of short-fibre reinforcement on the fracture behaviour of a bulk liquid crystal polymer

The microstructure and some mechanical properties of a liquid crystal polymer (LCP) and its short-fibre composites have been investigated. Injection moulded plates of the latter materials exhibit a layered structure well-known for many short-fibre reinforced polymer systems. A pronounced layered structure is also found in the neat LCP matrix, superimposed by a certain degree of molecular orientation. The special, microstructural character of the matrix polymer results in a high anisotropy of the mechanical properties of all materials investigated. In particular, this is found for the tensile strength, the fracture toughness and the fatigue crack propagation. The composites show nearly no improvement or even a reduction in their performance, compared to the matrix material, as far as these properties are concerned. This can, in part, be correlated to microscopic failure mechanisms detected by scanning electron microscopy of the fractured surfaces, revealing that the fibre-matrix bond strength is relatively poor.     

Theoretical investigation on the stability,mechanical and thermal properties of the newly discovered MAB phase Cr_4AlB_4

The nanolaminated MAB phases have attracted great research interests in recent years due to their similarities to MAX phases, which display both metallic and ceramic-like properties. In the present work, a newly discovered MAB phase Cr_4AlB_4 was investigated by first principles calculations. Energy evaluations indicate that Cr_4AlB_4 can be synthetized in Al lean condition, which can further transform to Cr_2AlB_2 in Al rich condition. The full set of elastic properties and their dependences on temperature, ideal strengths under different tensile and shear deformations, and thermal expansions of Cr_4AlB_4 were predicted. The results reveal that the properties of Cr_4AlB_4 are dominated by the layered crystal structure and weak bonding nature between Al and Cr_2B_2 layers, including low elastic stiffness and large thermal expansion along [010] direction(the stacking direction of Al and Cr_2B_2 layers), low shear resistances in(010) plane,and preferentially cleavage along and/or shear in(010) plane. Therefore, it suggests that Cr_4AlB_4 displays similar mechanical properties to MAX phases, including readily machinable, thermal shock resistant, and damage tolerant. In combination with the fact that Cr, Al and B all can form dense oxides to protect the material from further oxidation, Cr_4AlB_4 is regarded as a promising high temperature ceramic.