INVESTIGATION ON SELF-PROPAGATING HIGH-TEMPERATURE SYNTHESIS OF TiAl INTERMETALLIC COMPOUND

The self-propagating high-temperature syn-thesis method was used to synthesize the TiAl intermetalliccompound,and two kinds of synthesis modes were studied inthis paper.The results show that the thermal explosion modeis suitable for the synthesis of TiAI,the pre-heating tempera-ture has a great influence on the synthesis.Microstructurestudy show that the density of the sample fabricated by thermal explosion mode is higher than that fabricated by propa-gating mode.     

跨语言文献相似度的分析方法

对不同语言的句对齐文献资料进行分析,提出了基于多语主题模型的跨语言文献相似度的计算方法.首先,对收集整理的不同语言(中文、英文、韩文)文献构建数据模型,通过分词、分词结果修正及选择、词权重计算等预处理工作构造词项-文档矩阵.其次,建立多语主题语义空间,将译成3种不同语言的文献映射到语义空间,在语义空间中每一主题都由3种语言构成.最后,通过其语义空间中对应的主题计算比较不同语言间的文献相似度.实验结果显示,不同语言之间的文献相似度可以直接在语义空间中计算,且相似度计算的准确性在90%以上,验证了本文方法在跨语言文献相似度计算时的有效性.     

基于X-LiNbO3/SiO2/Si低温漂、大机电耦合SH-SAW谐振器的设计

铌酸锂(LN)单晶薄膜具有较高的机电耦合系数(k² eff＞30%),其水平剪切(SH)声学模式常被应用于开发具有大机电耦合系数的薄膜声学谐振器和超宽带滤波器。但LN 的频率温度系数较大(TCF ＞ -50×10^-6/℃),这不仅会降低滤波器的可用有效带宽,同时也会限制器件的功率处理能力。采用3D周期有限元模型对基于X 切LN/SiO₂/Si结构SH 声表面波(SH-SAW)谐振器进行了优化研究。研究结果表明,当SH-SAW 传播角ψ=-10°~-20°、LN和SiO₂ 膜厚分别为hLN=0.1λ 和h_SiO2 =0.2λ(λ 为叉指换能器周期)、铝电极金属化率η=0.4、电极相对厚度h_Al/λ=5%~10%时,SH-SAW 谐振器的 k² eff 约为30%,且其TCF＜-20×10^-6/℃,有望用于开发新一代的低温漂、超宽带5G SAW 滤波器。     

圆形截面的四边形元素网格剖分

叙述了一种对圆形截面进行网格剖分的方法。圆形截面剖分后由不同类型的元素表示,节点的创建和元素的生成依据节点和元素在圆内的位置而采用不同的方式分别生成。     

基于名义尺度的空间自相关指数测度方法研究*

从空间自相关的基本构成出发,提出了一种测度名义尺度的空间自相关指数——自邻接指数,给出了基于名义尺度下全局空间自相关和局部空间自相关的测度方法,并在ArcView平台下通过Avenue二次编程进行了算法实现。最后通过例子展示了自邻接指数在土地利用格局分析中发挥的重要作用。     

多功能Pt-Ce6纳米平台作为过氧化氢纳米酶和NIR-Ⅱ光热剂用于增强PDT/PTT肿瘤治疗

实体肿瘤的缺氧严重影响着基于氧气的光动力疗法(PDT)的效果.另外,单一治疗模式通常难以达到满意的治疗效果.为此,我们设计合成了一种多功能纳米复合材料Pt-Ce6用于克服肿瘤乏氧,实现PDT/PTT协同治疗.在该体系中,我们使用多孔Pt纳米粒子作为过氧化氢纳米酶、近红外二区(NIR-Ⅱ)光热转换剂和光敏剂二氢卟吩e6(...     

Matisse: A System-on-Chip Design Methodology Emphasizing Dynamic Memory Management

MATISSE is a design environment intended for developing systems characterized by a tight interaction between control and data-flow behavior, intensive data storage and transfer, and stringent real-time requirements. Matisse bridges the gap from a system specification, using a concurrent object-oriented language, to an optimized embedded single-chip hardware/software implementation. Matisse supports stepwise exploration and refinement of dynamic memory management, memory architecture exploration, and gradual incorporation of timing constraints before going to traditional tools for hardware synthesis, software compilation, and inter-processor communication synthesis. With this approach, specifications of embedded systems can be written in a high-level programming language using data abstraction. Application of MATISSE on telecom protocol processing systems in the ATM area shows significant improvements in area usage and power consumption.     

Single-Step Fast Tissue Clearing of Thick Mouse Brain Tissue for Multi-Dimensional High-Resolution Imaging

Recent advances in optical clearing techniques have dramatically improved deep tissue imaging by reducing the obscuring effects of light scattering and absorption. However, these optical clearing methods require specialized equipment or a lengthy undertaking with complex protocols that can lead to sample volume changes and distortion. In addition, the imaging of cleared tissues has limitations, such as fluorescence bleaching, harmful and foul-smelling solutions, and the difficulty of handling samples in high-viscosity refractive index (RI) matching solutions. To address the various limitations of thick tissue imaging, we developed an Aqueous high refractive Index matching and tissue Clearing solution for Imaging (termed AICI) with a one-step tissue clearing protocol that was easily made at a reasonable price in our own laboratory without any equipment. AICI can rapidly clear a 1 mm thick brain slice within 90 min with simultaneous RI matching, low viscosity, and a high refractive index (RI = 1.466), allowing the imaging of the sample without additional processing. We compared AICI with commercially available RI matching solutions, including optical clear agents (OCAs), for tissue clearing. The viscosity of AICI is closer to that of water compared with other RI matching solutions, and there was a less than 2.3% expansion in the tissue linear morphology during 24 h exposure to AICI. Moreover, AICI remained fluid over 30 days of air exposure, and the EGFP fluorescence signal was only reduced to ~65% after 10 days. AICI showed a limited clearing of brain tissue >3 mm thick. However, fine neuronal structures, such as dendritic spines and axonal boutons, could still be imaged in thick brain slices treated with AICI. Therefore, AICI is useful not only for the three-dimensional (3D) high-resolution identification of neuronal structures, but also for the examination of multiple structural imaging by neuronal distribution, projection, and gene expression in deep brain tissue. AICI is applicable beyond the imaging of fluorescent antibodies and dyes, and can clear a variety of tissue types, making it broadly useful to researchers for optical imaging applications.