A Theoretical Study on the Conductivity of Carbon Doped BNNT

From the changes in energy band, density of state (DOS) and electronic structure calculated by the DFT/B3LYP method, the conductivity of carbon doped boron‐nitride nanotube (BNNT), which is formed by C‐C bond substituting B‐N bond, was discussed. The results indicate that the substitution will strengthen the conductivity of the tube, and its semi‐conductivity might be adjusted by controlling the substitution.     

A study of preferential solvation of N-alkyl pyridinium iodides in mixed solvents containing acetonitrile

The charge transfer (CT) band maximum of N-alkyl pyridinium iodide (NAPI) has been studied as a function of the composition of binary mixed dipolar aprotic solvents. The deviation from linearity of the energy maximum (E₁₂) and the mole fraction (of a component solvent) plot is explained as due to a preferential solvation by the more polar cosolvent in the binary mixture. The extent of preferential solvation has been observed to vary with the composition, the maximum being towards the less-polar end. The role of hydrogen bond donating ability of a solvent in preferential solvation is discussed.     

Effect of the ionic strength of salts on retention and overloading behavior of ionizable compounds in reversed-phase liquid chromatography I. XTerra-C18

The influence of the salt concentration (potassium chloride) on the retention and overloading behavior of the propranolol cation (R'-NH2+ -R) on an XTerra-C18 column, in a methanol:water solution, was investigated. The adsorption isotherm data were first determined by frontal analysis (FA) for a mobile phase without salt (25% methanol, v/v). It was shown that the adsorption energy distribution calculated from these raw adsorption data is bimodal and that the isotherm model that best accounts for these data is the bi-Moreau model. Assuming that the addition of a salt into the mobile phase changes the numerical values of the parameters of the isotherm model, not its mathematical form, we used the inverse method (IM) of chromatography to determine the isotherm with seven salt concentrations in the mobile phase (40% methanol, v/v; 0, 0.002, 0.005, 0.01, 0.05, 0.1 and 0.2 M). The saturation capacities of the model increase, q(s,1) by a factor two and q(s,2) by a factor four, with increasing salt concentration in the range studied while the adsorption constant b1 increases four times and b2 decreases four times. Adsorbate-adsorbate interactions vanish in the presence of salt, consistent with results obtained previously on a C18-Kromasil column. Finally, besides the ionic strength of the solution, the size, valence, and nature of the salt ions affect the thermodynamic as well as the mass transfer kinetics of the adsorption mechanism of propranolol on the XTerra column.     

Silver nanoparticles dispersed within amphiphilic star-block copolymers as templates for plasmon band materials

Formation of silver nanoparticles has been developed based on a template technique. Amphiphilic star-block copolymers employed as single molecule template, utilizing the coordination of Ag⁺ ions with carboxyl groups in the core of the star-block copolymer. Silver nanoparticles have been prepared by the addition of chemical reductant, e.g., NaBH₄. The solution of the resultant nanosphere composites showed yellow due to the surface plasmon resonance. These composites were soluble in organic solvents, because hydrophobic corona of the star-block copolymer protected the fabricated silver nanoparticles from aggregation.     

一种应用于HDMI接收端的宽频带锁相环设计

基于110 nm CMOS工艺设计了一种应用于HDMI接收端电路的宽频带低抖动锁相环。采用一种改进型双环结构电荷泵,在25～250 MHz的宽输入频率范围内实现了快速锁定。通过高相噪性能的伪差分环形振荡器产生了调谐范围为125 MHz～1.25 GHz的时钟信号。仿真实验结果表明,该锁相环的锁定时间小于1.2μs,在振荡器工作频率为0.8 GHz时,其相位噪声为-100.0 dBc/Hz@1 MHz,输出时钟峰峰值抖动为4.49 ps。     

一种变压器巴伦馈电的超短波紧耦合阵列天线

紧耦合阵列天线(Tightly Coupled Array, TCA)具有超宽带、低剖面、宽角扫描等特点,近年来受到国内外学者的广泛关注。然而,在甚高频(VHF)、特高频(UHF)频段TCA 由于馈电网络设计困难等原因现有的研究报道很少。为了填补这一空白,本文设计并测试了一款变压器巴伦馈电的TCA,利用变压器巴伦解决了单元平衡馈电困难问题,同时采用短路枝节抑制E面共模谐振,采用频率选择表面(FSS)匹配层改善宽角扫描阻抗匹配。实测结果表明,该天线在110~520 MHz 频带内、±40°扫描角范围内电压驻波比<2.5,和仿真结果吻合。     

Minimizing Energy Barrier in Intermediate Connection Layer for Monolithic Tandem WPeLEDs with Wide Color Gamut

Perovskite light-emitting diodes (PeLEDs) show promising prospects in the wide color gamut display owing to their ultra-narrow full width at half maximum (FWHM). However, up to now, all perovskite white LEDs integrated by standard red, green, and blue perovskite emitters, namely, monolithic white PeLEDs (WPeLEDs), have been rarely reported, owing to facing some issues, e.g., solvent incompatibility in solution technique, ion exchange, and energy transfer between different emission centers. Herein, centered on these issues, an optimal intermediate connection layer (ICL) of Po-T2T/LiF/Ag/HAT-CN/MoO₃ is adopted to successfully develop monolithic tandem multicolor PeLEDs and WPeLEDs for the first time. The multicolor PeLEDs can achieve the best external quantum efficiency of 1.8% and the highest luminance of 4844 cd m⁻². Besides, the red/green/blue (R/G/B) monolithic tandem WPeLED shows a standard white International Commission on Illumination coordinate of (0.33, 0.33) and achieves an extremely wide color gamut reaching  National Television Standards Committee of 130%. This study is the first to realize the standard R/G/B co-electroluminescence in a monolithic perovskite device and offers a feasible strategy for developing wide-color gamut perovskite displays.     

一种高效的大功率宽带整流电路

提出了一种由π型匹配枝节、整流二极管、直通滤波器组成的高效大功率宽带整流电路。采用2只HSMS-282P肖特基二极管桥设计单级倍压整流电路,使电路在整流效率不下降的情况下提升输入的功率容量;采用π型匹配枝节实现阻抗匹配,使电路具有宽频特性,同时其并联短路枝节可以作为输入滤波器,实现小型化和整流效率的提高。直通滤波器用于抑制基频和二极管非线性产生的高次谐波,以提高整流效率。实测结果表示：在2.05~2.6 GHz带宽内整流效率大于60%;在2.45 GHz工作频率和35 dBm输入功率下,整流电路在330 Ω负载上获得70%的整流效率。该整流电路具有整流效率高、功率容量大、频带宽的特性,可为工程人员设计大功率微波整流电路提供设计指导。     

通信波段稀土离子掺杂固态量子存储进展

量子互联网是实现多方量子通信、分布式量子计算等量子信息技术的重要基础,量子存储器作为实现互联网的重要部件,对量子信息技术的发展、应用具有举足轻重的作用。如今遍布全球的光纤网络已经是信息传输的有力载体,通信波段的量子存储器因容易嵌入到当前的光纤网络中而备受重视。聚焦于稀土离子掺杂固态体系的通信波段光量子存储,首先介绍稀土离子掺杂固态量子存储的基本原理,包括稀土掺杂材料特性以及存储协议等,然后介绍目前的研究现状,最后简要分析其未来的发展趋势,并对量子互联网的构建做出展望。     

W波段64通道相控阵微系统设计与实现

相控阵微系统的主要特征是电路与天线的高度融合集成,将三维微纳集成技术和微电子技术紧密地结合在一起,切合相控阵高频化、小型化和低成本的发展需求。本文设计了一款W波段的封装天线相控阵微系统,该相控阵采用硅基三维集成的方式将T/R多功能芯片、天线阵列集成在一个微系统模块中,并详细介绍了基于硅工艺的多功能收发芯片设计和相控阵封装天线设计。给出了相控阵微系统的测试结果。该微系统具有高集成度、高性能、低成本的特点,可以为高速无线通信、高精度探测和成像等应用提供一个较优的技术路径。