碳纤维在干扰材料和含能材料中的应用研究

碳纤维具有高强度、高硬度、高模量、耐高温、耐磨损等优点,且具有导电性能,在热防护技术、冲击定位技术、制孔技术等专业领域具有广泛应用.同时,由于碳纤维的性能特点,在干扰材料和含能材料中也开展了很多研究.文中介绍了碳纤维在红外、雷达、烟幕等干扰材料和发射药、推进剂、炸药等含能材料中的应用研究成果,为碳纤维及其复合材料在干扰...     

硼烯朝电子器件应用迈进一大步

<正>美国西北大学Mark Hersam团队在硼烯(borophene)的研究中取得重大进展,开始着力研究其在纳米电子器件中的应用。Mark Hersam教授是目前世界上研究2D材料方面的先驱。他所带领的团队去年使用电子束蒸发器在超高真空度下烧蚀固体硼,在银的表面上成功制备出了只有一个原子厚度的硼材料———硼烯。时隔一年,研究重点已从硼烯属性表征     

稀土发光材料的发光机理及其应用

稀土是我国的重要战略资源,稀土发光材料在一些方面已得到普遍应用并在新能源和生物医学等方面具有重要的应用前景。该文给出了稀土离子发光材料的基本原理,介绍了含稀土离子发光材料在节能灯、白光半导体发光二极管显示(LED)用荧光粉、等离子显示(PDP)用荧光粉等领域的应用,对在上转换发光、生物荧光标记和下转换提升太阳能效率等方面的应用前景进行了总结和展望。     

欧姆接触镍电极的研究

对镍电极浆料进行了实验研究。材料配方的选择和工艺的优化是实验的关键。实验中用玻璃粉和硼粉作为镍电极浆料的粘合剂和抗氧化剂，其中镍粉的质量分数不得低于65％，研制出的镍浆料可在大气中于810℃烧结在PTC等半导瓷上构成电极。通过扫描电镜(sEM)可以发现镍电极能牢固地附着在陶瓷体上并具有良好的欧姆接触性能。     

低温共烧陶瓷用硼硅酸盐玻璃的研究进展

概述了低温共烧玻璃陶瓷复合材料体系中所采用的硼硅酸盐玻璃的组成、工艺、应用技术参数。比较了锌、铅、钡硼硅酸盐玻璃组成、掺杂量对玻璃陶瓷的烧结特性的影响。指出了不同硼硅酸盐玻璃材料的优缺点和在低温共烧陶瓷技术中的适用范围。     

空气中烧成镍电极浆料的研究

介绍了空气中烧成的Ni电极浆料的制备。讨论了浆料中玻璃粉、硼粉含量及烧渗工艺等对电极性能的影响。结果表明:浆料中Ni粉的纯度应为99.5%,粒度为500目;w(Ni)应不低于65%;玻璃粉的软化温度为450℃左右;粒度为300目,w(玻璃)为20%左右。加入硼粉系作为抗氧化剂。于810℃的大气中烧渗,保温5 min,此贱金属镍电极可牢固地附着在陶瓷基体上,并具有良好的欧姆接触性能。     

关于硼杂质在二氧化硅中扩散机理的探讨

实验发现,在硅平面器件硼预沉积时,硼杂质在二氧化硅中的扩散系数远远偏离理论值.为进一步解析这种现象,本文提出了一种硼杂质在二氧化硅中具有双重扩散机构及分层扩散的初步设想.我们认为,利用这一设想,能较好地解析实验结果.实践表明,本实验结果为硅平面器件硼扩散工艺的改革提供了参考依据,并取得了较好的效果.     

含能材料激光起爆技术

激光起爆技术具有安全、可靠、低成本等传统电起爆无法取代的特点,是未来含能材料钝感起爆的重要途径．针对不同激光与含能材料作用方式,评述了激光热起爆、冲击起爆、光起爆,以及新型光敏含能材料等方面的研究进展,探讨了未来激光起爆技术及光敏炸药的研究方向。     

六硼化镧材料的化学腐蚀工艺研究

目前,阴极发射体材料多存在逸出功大，可靠性及均匀性低，发射性能低、不能自动调节活性物质更替的速度等方面的问题．与之相比,六硼化镧既具有可恒定地维持一个活性阴极表面．同时具有高导电率和良好的热稳定性及化学稳定性，是作为阴极发射体的理想材料．而对六硼化镧的化学腐蚀在以其为阴极的阴极发射体制备工艺中起着至关重要的作用，本文简述了对材料的化学腐蚀工艺的初步研究，并得到了图形化的六硼化镧表面。     

等离子体提纯硅粉的实验研究

本文阐述了等离子体工艺在硅粉提纯方面的应用，在真空条件下，利用ＨＣｌ或含氯气体化合物，经射频辉光放电形成等离子体与硅粉中的杂质反应，可以在较低的温度下（２００℃～４００℃）、较短的时间（１～２小时）内，除去硅粉中的大部分杂质，而且操作简单，功耗较低。     

高热导率陶瓷材料的进展

叙述了在电子器件上常用高热导率陶瓷材料的性能和应用，主要包括BeO，BN，AIN等三种陶瓷材料。特别介绍了AIN陶瓷的发展前景及其最新应用。     

外军激光类防空反导装备发展路线分析

研究了欧美军事强国开展的多项激光类防空反导装备研发和应用转化过程,结合外军发展的典型激光对抗装备的性能及其特点,介绍了国外激光类防空反导装备的发展历程以及装备的研制情况。指出了在现代战争中发展激光类防空反导装备的优势和重要性,分析总结了外军激光类防空反导装备的发展现状和趋势。     

含能材料激光点火性能的试验研究

分析了固体含能材料光吸收性的特点,采用了既利于材料吸收又便于普通光纤传输的大功率固体Nd~(3+):YAG激光器,对各种含能材料进行了激光点火性能的试验研究,成功测得了各种含能材料的点火过程曲线,并对影响含能材料激光点火性能的各种因素(激光能量、脉冲持续时间、不同药粒等)进行了实验分析。结果表明,不同含能材料的激光点火性能存在较大的差异,这不仅与激光特性有关,而且与含能材料的热物性有着密切的关系。这必将为含能材料激光点火系统的设计提供参考和依据。     

Plasmon-Acoustic Transducers Based on Graphene–2D Boron Nitride Structures for the Terahertz-Frequency Range

Semiconductors - Graphene and 2D hexagonal boron nitride isomorphic to it are promising materials for application in nanoacoustics. Therefore, more detailed study on the possibilities of the...     

Miniaturized calorimeter for thermal screening of energetic materials

The use of chip-scale calorimeters for research and development has increased during the last two decades. The high sensitivity of these devices allows their use for characterization of very small amounts of sample. However, the potential for using them for screening of highly energetic materials (i.e., explosives) has not been fully explored. In this paper, we present the design aspects of two chip-scale calorimeter prototypes based on thick silicon membranes for liquid and solid thermal characterizations. The ultimate goal of the proposed work is to produce a portable calorimeter that can be incorporated as a new approach for detection of highly energetic materials such as explosives based on the information obtained from the calorimeter. The concept of this application is that indirect detection via the determination of thermal energy released in exothermic reactions can be detected by chip-scale calorimetric sensors. Details about the calorimeter design using finite element analysis are presented along with the fabrication procedure of the proposed sensor. Finally, preliminary results that provide experimental validation of the device design are presented.     

Estimation of effective diffusion time in a rapid thermal diffusionusing a solid diffusion source

Two-step rapid thermal diffusion (RTD) of phosphorus and boron using a solid diffusion source is described. From the application of the Boltzmann-Matano method to SIMS profiles of phosphorus and boron after RTD, it has been found that some additional correction terms to the effective diffusion time must be introduced. In the phosphorus diffusion case, the increment of the effective diffusion time due to the supersaturation of point defects during the cooling cycle is about 3 s. In the case of boron diffusion, the additional effective diffusion time is a strong function of diffusion temperature. This has been explained as the effect of initial growth of the boron-rich layer during the glass-transfer process. The introduction of additional correction terms to the effective diffusion time makes it possible to treat the RTD process in a similar manner to normal diffusion     

激光波长对含能材料起爆阈值的影响

为了解激光波长对含能材料起爆阈值的影响,降低含能材料的激光起爆能量,提高激光激励源的小型化程度,采用飞行时间质谱技术和Bruccton升降法,测试了波长1 064 nm和532 nm两种激光对泰安(PETN)的解离谱图和起爆阈值,分析了波长对起爆机理的影响。结果表明:含能材料激光起爆对波长具有选择性,每种含能材料均具有一些有利于起爆的特征吸收波长;不同波长(1 064 nm和532 nm)激发时PETN存在不同的解离机理。相对于532 nm激光,接近特征吸收的1 064 nm激光能够加速PETN的解离,并使其50%发火能量降低14%。因此,采用含能材料特征吸收波长激光作为起爆激励源,能有效的减少含能材料的起爆阈值。     

2D Boron Sheets: Structure,Growth, and Electronic and Thermal Transport Properties

The structures of boron clusters, such as flat clusters and fullerenes, resemble those of carbon. Various two‐dimensional (2D) borophenes have been proposed since the production of graphene. The recent successful fabrication of borophene sheets has prompted extensive researches, and some unique properties are revealed. In this review, the recent theoretical and experimental progress on the structure, growth, and electronic and thermal transport properties of borophene sheets is summarized. The history of prediction of boron sheet structures is introduced. Existing with a mixture of triangle lattice and hexagonal lattice, the structures of boron sheets have peculiar characteristics of polymorphism and show significant dependence on the substrate. Due to the unique structure and complex B? B bonds, borophene sheets have many interesting electronic and thermal transport properties, such as strong nonlinear effect, strong thermal transport anisotropy, high thermal conductance in the ballistic transport and low thermal conductivity in the diffusive transport. The growth mechanism and synthesis of borophene sheets on different metal substrates are also presented. The successful prediction and synthesis will shed light on the exploration of new novel materials. Besides, the outstanding and peculiar properties of borophene make them tempting platform for exploring novel physical phenomena and extensive applications.     

Utilising solution processed zirconium acetylacetonate as an electron extracting layer in both regular and inverted small molecule organic photovoltaic cells

Interfacial layers are commonly employed in organic photovoltaic (OPV) cells in order to improve device performance. These layers must be transparent, stable, be compatible with the photo-active materials and provide efficient charge extraction with a good energetic match to the relevant organic material. In this report we demonstrate the compatibility of zirconium acetylacetonate (ZrAcac) electron extracting layers in both regular and inverted small molecule OPV cells. When the ZrAcac was processed in both air and under N₂, low work function (3.9 and 3.7 eV respectively), highly transparent layers were formed, with good energetic alignment to both C₆₀ and hexachlorinated boron subphthalocyanine chloride (Cl₆-SubPc) acceptors. Initial measurements indicate similar stabilities when using the ZrAcac in either device architecture. These results indicate that the ZrAcac layer can be used as a direct replacement for the commonly used bathocuproine (BCP) in small molecule OPV cells.     

Development and Testing of Energetic Materials: The Concept of High Densities Based on the Trinitroethyl Functionality

The development of new energetic materials is an emerging area of materials chemistry facilitated by a worldwide need to replace materials used at present, due to environmental considerations and safety requirements, while at the same time securing high performance. The development of such materials is complex, owing to the fact that several different and apparently mutually exclusive material properties have to be met in order for a new material to become widely accepted. In turn, understanding the basic principles of structure property relationships is highly desirable, as such an understanding would allow for a more rational design process to yield the desired properties. This article covers the trinitroethyl functionality and its potential for the design of next generation energetic materials, and describes relevant aspects of energetic materials chemistry including theoretical calculations capable of reliably predicting material properties. The synthesis, characterization, energetic properties, and structure property relationships of several new promising compounds displaying excellent material properties are reported with respect to different kinds of applications and compared to standard explosives currently used. Based on a review of trinitroethyl‐containing compounds available in the literature, as well as this new contribution, it is observed that high density can generally be obtained in a more targeted manner in energetic materials taking advantage of noncovalent bonding interactions, a prerequisite for the design of next generation energetic materials.