Algorithm Study on Reconstruction of Refractive Angles in Fan Beam Diffraction Enhanced Computed Tomography

Based on the 360° computing method of refractive angle for parallel beam diffraction enhanced imaging computed tomography （DE-CT） technique, a new algorithm used to calculate the refractive angle for fan-beam DE-CT technique is developed. The refractive index gradient can be obtained by using the new algorithm with projection data of an object in the range of 0 - 360°, and the new algorithm only needs to set the analyser at half slope position of the rocking curve.     

超声波在液体中的传播速度与温度的关系

根据超声光栅的原理,在分光计上测出了超声波在不同温度下的纯净水中的传播速度.通过最小二乘法进行数据拟合,得到了传播速度与温度的近似公式.     

Barrier Enhancement Effect of Postannealing in Oxygen Ambient on Ni/AIGaN Schottky Contacts

Al0.2 Ga0.8N/GaN samples are grown by metalorganic chemical vapour deposition （MOCVD） method on （0001） sapphire substrates. A 10nm-thick Ni layer is deposited on AlGaN as the transparent Schottky contact. The effect of postannealing in oxygen ambient on the electrical properties of Ni/AlGaN is studied by current-voltage- temperature （I-V-T） measurement. The annealing at a relatively low temperature of 300℃ for 90 s results in a decrease of the ideality factor from 2.03 to 1.30 and an increase of the Schottky barrier height from 0.77eV to 0.954 e V. The I-V-T analysis confirms the improvement originated from the formation of NiO, a layer with higher resistance, which could passivate the surface states of AlGaN and suppress the tunnelling current. Furthermore, the annealing also leads to an increase of the transmittance of the contacts from 57.5% to 78.2%, which would be favourable for A1GaN-based photodetectors.     

酸-碱交替沉淀法铜基甲醇合成催化剂的优化制备与表征

采用酸-碱交替沉淀法制备了Cu基甲醇合成催化剂放大样(500 g), 并用X射线衍射、低温N2吸附和扫描电子显微镜等对催化剂进行了表征,系统考察了制备条件(搅拌速度、溶液滴加速度、盐和碱溶液浓度等)对催化剂性能的影响. 结果表明,采用酸-碱交替沉淀法制备的Cu基甲醇合成催化剂中, Cu和Zn组分以无定形的CuO-ZnO固溶体存在,使得CuO和ZnO的晶粒减小,导致催化剂的晶粒度较小,粒径尺寸分布较均匀,结晶度相对较低,有利于提高催化剂的比表面积. 采用酸-碱交替沉淀法制备的Cu基甲醇合成催化剂具有较高的Cu分散度和较大的Cu比表面积. 在优化条件下制备的催化剂的活性和耐热性均比国内外工业催化剂高.     

Simultaneous wireless information and power transfer transmitting architecture based on asynchronous space-time-coding digital metasurface

Simultaneous wireless information and power transfer(SWIPT) architecture is commonly applied in wireless sensors or Internet of Things(IoT) devices, providing both wireless power sources and communication channels. However, the traditional SWIPT transmitter usually suffers from cross-talk distortion caused by the high peak-to-average power ratio of the input signal and the reduction of power amplifier efficiency. This paper proposes a SWIPT transmitting architecture based on an asynchronous spac...     

Low-temperature Catalytic Reduction of Nitrogen Monoxide with Carbon Monoxide on Copper Iron and Copper Cobalt Composite Oxides

通过共沉淀法, 在低温下制备了铜铁复合氧化物CuO/Fe2O3和铜钴复合氧化物CuO/Co3O4．利用GC微反应器评价了这些复合氧化物的催化活性和热稳定性,结果表明, CuO/Fe2O3和CuO/Co3O4的NO100%转化温度分别为80和90 ℃,该催化活性和热稳定性在较宽的温度和较长的时间范围内都能得以保持．此外,还系统研究了试剂的摩尔比率、NaOH的体积、陈化时间、煅烧温度和煅烧时间对该复合氧化物催化活性的影响．     

LED梯度折射率封装结构的蒙特卡罗模拟

针对封装胶中掺杂纳米颗粒以及采用梯度折射率的LED封装模式,用蒙特卡罗方法模拟光在胶体中的传播,分析散射系数对透光率的影响.结果表明,透光率随散射系数增大而减小.对于固定的封装层数,各层均采取最佳折射率值时,透光率可以达到最大.梯度折射率值逐渐减小的多层纳米掺杂封装结构,透光率高于传统的封装模式,能够提高LED的出光效率.     

线性时滞系统的时滞相关稳定性分析

对于存在状态时滞的线性时滞系统,分为固定时滞及时变时滞两种情形,基于Lyapunov-Krasovskii理论分析稳定性,通过时滞划分,得到以LMI形式给出的一种保守性小的渐近稳定性条件,且能够处理任意变化的变时滞问题.实例表明只需粗略划分就能大大提高保守性能,为了兼顾计算负担,r取较小数值即可.并且LMI中的决策变量少,形式简洁.     

高密度噬菌体抗体芯片对细胞表面蛋白的识别

采用正常人和白血病患者的白细胞对人源噬菌体抗体库进行淘选, 以获得对两种细胞表面蛋白特异的抗体. 通过pVIII展示系统, 使抗体以多价展示于重组噬菌体颗粒表面, 从上述两组中各挑选出48个克隆分别固定于环氧基片上, 并以空白噬菌体和牛血清白蛋白作为对照, 制成高密度噬菌体抗体芯片. 取来自3名正常人和3名白血病患者的白细胞裂解物样品, 用荧光染料Cy3标记, 与噬菌体抗体芯片反应, 对微阵共聚焦扫描得到的荧光图谱进行分析. 在白血病白细胞表面蛋白的识别图谱中有8组斑点显著不同于正常图谱. 由此表明, 噬菌体抗体芯片可用于识别细胞表面蛋白.