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Influence of niobium and yttrium on plastic deformation energy and plasticity of Ti-based amorphous alloys
No full textMany amorphous alloys have been developed to date, but the low plasticity has limited their application. To achieve an amorphous alloy with high plasticity, a series of (Ti40Zr25Cu9Ni8Be18)(100-x)TMx (x=0, 1, 2, 3, 4 at.%, TM=Nb, Y) alloys were designed to study the influence of Nb and Y addition on the plasticity. The amorphous samples were prepared using the vacuum melting and copper mold casting process. The microstructures, glass forming ability and mechanical properties of the alloys were investigated by X-ray diffractometry (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), depth-sensitive nanoindentation, and uniaxial compressive test. The plasticity of different bulk amorphous alloys was investigated by measuring the plastic deformation energy (PDE) during loading. The relationship between the PDE value and plasticity in bulk amorphous alloys was explored. Results show that Nb addition decreases the PDE value and promotes the generation of multiple shear bands, which significantly increases the fracture strength and plasticity, while the addition of Y element reduces the fracture strength and plastic strain of the alloy
Engineering the interface between LiCoO2 and Li10GeP2S12 solid electrolytes with an ultrathin Li2CoTi3O8 interlayer to boost the performance of all-solid-state batteries
No full textSulfide-based all-solid-state lithium-ion batteries (ASSLIBs) are promising candidates in the next generation of energy storage technology; the voltage mismatch and the resulting side reactions at the interface between the cathode and the solid electrolyte, however, dramatically deteriorate their cycling performance. Herein, for the first time, we report that the chemical interaction between LiCoO2 (LCO) and TiO2 can be regulated by two additives, carbon and Li, which in situ form a continuous ultrathin pure-phase Li(LCTO) layer with a stable 3D network of spinel structures, relatively low electronic conductivity (2.5 x 10 S cm) and high lithium diffusion coefficient (D = 8.22 x 10) on the surface of LCO. When assembled in ASSLIBs, such an LCTO layer functions as an interlayer between the LCO and the Li solid electrolyte (LGPS). As a consequence, the original interface LCO/LGPS is substituted by two new interfaces LCO/LCTO and LCTO/LGPS. DFT calculations indicate that, compared with the LCO/LGPS, the new interfaces are not only thermodynamically and electrochemically more compatible, but also have higher interfacial affinity. Therefore, the relevant ASSLIB exhibits evidently reduced interfacial impedance, and it also displays a high initial capacity of 140 mA h g and a reversible discharge specific capacity of 116 mA h g after 200 cycles at room temperature (0.1C). In comparison, the ASSLIB assembled without the LCTO interlayer delivers an initial capacity of 98 mA h g and only retains 22.4% capacity after 100 cycles (0.1C). Even at a high cutoff voltage (4.5 V vs. Li/Li), the ASSLIB with the LCTO interlayer could also exhibit a high initial capacity of 180 mA h g and a remarkable retention of 132 mA h g after 100 cycles
Preparation, Properties and Mechanisms of Carbon Fiber/Polymer Composites for Thermal Management Applications
No full textWith the increasing integration and miniaturization of electronic devices, heat dissipation has become a major challenge. The traditional printed polymer circuit board can no longer meet the heat dissipation demands of microelectronic equipment. If the heat cannot be removed quickly and effectively, the efficiency of the devices will be decreased and their lifetime will be shortened. In addition, the development of the aerospace, automobiles, light emitting diode (LED) and energy harvesting and conversion has gradually increased the demand for low-density and high thermal conductive materials. In recent years, carbon fiber (CF) has been widely used for the preparation of polymer composites due to its good mechanical property and ultra-high thermal conductivity. CF materials easily form thermal conduction paths through polymer composites to improve the thermal conductivity. This paper describes the research progress, thermal conductivity mechanisms, preparation methods, factors influencing thermal conductivity and provides relevant suggestions for the development of CF composites for thermal management
Ultrathin metal-organic framework nanosheets prepared via surfactant-assisted method and exhibition of enhanced anticorrosion for composite coatings
No full textAs a vital branch of two-dimensional material, organic framework material sparked wide interest, but generally water is a serious threat to its structure. Aiming to obtain organic framework materials with water stability, a bottom-up approach to building porphyrin-paddlewheel metal-organic framework (MOF) nanosheet assisted by surfactant is developed, where the obtained ultrathin nanosheet possesses more uniform scale and higher yield than traditional exfoliation obtained. Then Cu-MOF nanosheets are used as nanofillers into epoxy thermoset and prominently improve the protection properties of coatings compared with the controlled samples and bulk material demonstrated by the electrochemical measurement
基于SrAl_(2)O_(4):Eu，Dy，La长余辉发光材料的手印无背景显现研究
No full text以Al(NO_(3))_(3)和Sr(NO_(3))_(2)以及硝酸稀土为氧化剂、尿素为还原剂和燃料、H_(3)BO_(3)为助熔剂，采用燃烧法在较低温度下一步反应制备出SrAl_(2)O_(4):Eu，Dy，La长余辉发光材料，优化了炉温、尿素用量、H_(3)BO_(3)用量和La~(3+)掺杂浓度等制备条件。采用扫描电子显微镜、X-射线衍射谱、紫外-可见吸收光谱和荧光光谱分别对材料的微观形貌、晶体类型、紫外吸收以及发光性能进行了表征。结果表明，制备的长余辉发光材料的微观形貌为微米级多面体形状，晶体类型为纯单斜SrAl_(2)O_(4)晶型且结晶性能良好，在252和334 nm处出现了明显的紫外吸收峰，在365 nm激发波长下，514 nm处出现了较强的荧光发射峰。采用365 nm紫外光持续照射此长余辉发光材料30 s，在关闭光源后仍能观察到明亮的绿色发光。将长余辉发光粉末应用于一系列光滑客体表面潜在手印的无背景显现，详细考察了手印显现的对比度、灵敏度和选择性。结果表明，经长余辉发光模式增强处理的手印，其显现信号与背景噪声之间的对比反差强烈，乳突纹线的各级特征反应清晰明显，显现材料与乳突纹线之间的特异性吸附较强，具有对比度强、灵敏度高以及选择性好等优点。基于长余辉发光材料的手印显现方法特别适用于背景颜色复杂及荧光性能强烈的客体表面潜在手印的高质量、无背景显现，具有效果优良、操作简单、适用广泛以及针对性强等特点
基于气溶胶喷墨打印的太赫兹超材料结构仿真与制备研究
No full text本文介绍了利用气溶胶喷墨打印技术制备太赫兹波段的准光学元件。通过采用CST软件设计了CRR金属共振环和THz带阻滤波器。通过实验数据与数值模拟数据的比较,可以得出气溶胶喷墨打印技术在太赫兹领域的适用性
量子点发光二极管中电荷累积行为
No full text量子点发光二极管(QLED)是不需要额外光源的主动发光技术，在显示领域中的应用前景被广泛看好。寿命较短是影响QLED商业化的重要因素之一，并且其老化机理尚不清晰。在本工作中，我们通过自主搭建电荷提取装置，证实红光QLED在恒流驱动过程中，存在显著的电荷累积。累积电荷量随着驱动电流密度增加而增加，但当超过阈值电流密度(对应于开启电压)后逐渐趋于饱和。随着器件老化，亮度下降伴随着累积电荷量进一步增加。本工作对QLED老化过程中电荷累积规律的理解，能为QLED材料和界面的优化设计提供直观判据
定向鳞片石墨/PA66导热复合材料的性能
No full text采用廉价的鳞片石墨(FG)作为碳基导热材料,将FG定向排布于PA66板上,通过单向热压机,制备出高导热复合材料FG/PA66,研究了FG定向排布后复合材料的导热以及力学性能。研究表明,FG/PA66中FG定向排布形成高导热通路提高了复合材料的导热性能。当FG定向填充,含量为50%时复合材料热导率最高,高导热方向热导率为74 W/(m·K)。同时,采用硅烷偶联剂改善FG和PA66板的相容性,经过偶联剂处理之后复合材料的相比于未处理的复合材料不仅导热性能得到了提升,而且力学性能也得到了增强,含量为30%时热导率提升不明显,弯曲强度提升35%;含量为40%时热导率提升17%,弯曲强度提升34%;含量为40%时热导率提升37%,弯曲强度提升73%
高丰度稀土Y在永磁材料中的应用研究
No full text促进高丰度元素在稀土永磁材料中的应用是推动我国稀土资源平衡利用的重要举措，目前针对高丰度稀土La、Ce磁体的研究已经取得了一定的进展，而高丰度Y元素在永磁材料中的研究相对不足。获得稳定的物相结构和理想的微观组织结构是发展低成本高性能稀土永磁材料的关键。本课题组的研究表明，通过小原子半径的Y元素取代，能够稳定形成主相的四方结构，同时避免晶界杂相的生产；Y元素较强的主相形成能力能够促进Y取代磁体中天然的核壳组织结构的形成，进一步通过Y/Ce的共同取代，能够实现对高丰度元素在磁体内分布行为的调控；设计富稀土含镓的Y取代合金成分体系，在15 at.%Y取代Nd的条件下获得1.72 T的室温矫顽力，同时磁体具有较好的矫顽力热稳定性，与商业的含Dy磁体相当
新昌县数字经济发展路径研究
No full text为贯彻落实浙江省委数字经济"一号工程"战略部署,把握新一轮科技革命和工业革命带来的机遇,打造新技术、新产业、新业态和新模式,新昌县正在全面加快推进数字产业化、产业数字化和数字化治理,在传统产业转型升级、实现高质量发展等方面都取得了良好成效,特别是在中小企业中推广智能制造的难题上走出了一条以"数字化改造、网络化协同、平台化服务"为特色内涵的具有新昌特色的道路