一种用于卫星电视接收的FZP天线

本文用物理光学法对ＦＺＰ反射器的聚焦场、聚焦效率及偏轴扫描特性等进行初步分析，并由此提出一种使用ＦＺＰ天线实现多颗卫星信号同时接收的技术方案。原理性样机实际接收结果证实了其可行性     

球形与非球形颗粒反射膜后向散射特性的实验研究

本文报导了球形与非球形颗粒反射膜后向散射角分布特性。结果表明散射强度和角分布曲线与颗粒密度、颗粒尺寸和形状有关,选择合适的表面颗粒参数有可能控制其后向散射角分布特性。     

发展高电压等级真空断路器的技术问题探讨

本文对发展高电压等级真空断路器的关键技术问题，如触头材料，灭弧室耐压特性、电弧特性、弧后特性、波纹管设计及触头运动特性等进行了探讨，可为高电压等级真空断路器的设计提供依据。     

CO2对高密度水基钻井液性能影响规律及机理分析

准确判断污染物浓度以及其对钻井液影响规律和内在机制是制定有效的CO₂污染防治措施的重要前提,基于酸碱指示变色原理,改进了钻井液中碱度现场定量检测方法,提高测量的准确性和可操作性;采用现场取样跟踪分析以及室内模拟评价相结合的方法,研究了CO₂对高密度水基钻井液流变性和滤失造壁性的影响规律,并从胶体化学的角度出发,开展了CO₂对钻井液黏土胶体颗粒界面Zeta电位、粒度分布以及处理剂吸附影响的实验研究,分析了其作用机理。研究表明,高密度水基钻井液中碳酸根和碳酸氢根存在临界污染浓度,超过此浓度后,钻井液结构黏度和滤失量随其浓度增加而增加;碳酸根和碳酸氢根离子改变了黏土颗粒溶剂化程度和颗粒尺寸,主要表现为黏土胶体颗粒界面电动电势降低、亚微米级粒子减少,粗颗粒增多,黏土颗粒对护胶剂的吸附量减少,导致高密度钻井液黏土颗粒向聚结方向转化并缔合形成三维网络结构的胶凝状态,揭示了宏观性能变化内在机制。      

Highly Efficient Orange and Green Solid‐State Light‐Emitting Electrochemical Cells Based on Cationic IrIII Complexes with Enhanced Steric Hindrance

Highly efficient orange and green emission from single‐layered solid‐state light‐emitting electrochemical cells based on cationic transition‐metal complexes [Ir(ppy)₂sb]PF₆ and [Ir(dFppy)₂sb]PF₆ (where ppy is 2‐phenylpyridine, dFppy is 2‐(2,4‐difluorophenyl)pyridine, and sb is 4,5‐diaza‐9,9′‐spirobifluorene) is reported. Photoluminescence measurements show highly retained quantum yields for [Ir(ppy)₂sb]PF₆ and [Ir(dFppy)₂ sb]PF₆ in neat films (compared with quantum yields of these complexes dispersed in m‐bis(N‐carbazolyl)benzene films). The spiroconfigured sb ligands effectively enhance the steric hindrance of the complexes and reduce the self‐quenching effect. The devices that use single‐layered neat films of [Ir(ppy)₂sb]PF₆ and [Ir(dFppy)₂sb]PF₆ achieve high peak external quantum efficiencies and power efficiencies of 7.1 % and 22.6 lm W^–1) at 2.5 V, and 7.1 % and 26.2 lm W^–1 at 2.8 V, respectively. These efficiencies are among the highest reported for solid‐state light‐emitting electrochemical cells, and indicate that cationic transition‐metal complexes containing ligands with good steric hindrance are excellent candidates for highly efficient solid‐state electrochemical cells.     

Vibrational Energy Transport in Hybrid Ordered/Disordered Nanocomposites: Hybridization and Avoided Crossings of Localized and Delocalized Modes

Vibrational energy transport in disordered media is of fundamental importance to several fields spanning from sustainable energy to biomedicine to thermal management. This work investigates hybrid ordered/disordered nanocomposites that consist of crystalline membranes decorated by regularly patterned disordered regions formed by ion beam irradiation. The presence of the disordered regions results in reduced thermal conductivity, rendering these systems of interest for use as nanostructured thermoelectrics and thermal device components, yet their vibrational properties are not well understood. Here, the mechanism of vibrational transport and the reason underlying the observed reduction is established in detail. The hybrid systems are found to exhibit glass‐crystal duality in vibrational transport. Lattice dynamics reveals substantial hybridization between the localized and delocalized modes, which induces avoided crossings and harmonic broadening in the dispersion. Allen/Feldman theory shows that the hybridization and avoided crossings are the dominant drivers of the reduction. Anharmonic scattering is also enhanced in the patterned nanocomposites, further contributing to the reduction. The systems exhibit features reminiscent of both nanophononic materials and locally resonant nanophononic metamaterials, but operate in a manner distinct to both. These findings indicate that such “patterned disorder” can be a promising strategy to tailor vibrational transport through hybrid nanostructures.     

On the Relation between Morphology and FET Mobility of Poly(3‐alkylthiophene)s at the Polymer/SiO2 and Polymer/Air Interface

The influence of the interface of the dielectric SiO₂ on the performance of bottom‐contact, bottom‐gate poly(3‐alkylthiophene) (P3AT) field‐effect transistors (FETs) is investigated. In particular, the operation of transistors where the active polythiophene layer is directly spin‐coated from chlorobenzene (CB) onto the bare SiO₂ dielectric is compared to those where the active layer is first spin‐coated then laminated via a wet transfer process such that the film/air interface of this film contacts the SiO₂ surface. While an apparent alkyl side‐chain length dependent mobility is observed for films directly spin‐coated onto the SiO₂ dielectric (with mobilities of ≈10^?3 cm² V^?1 s^?1 or less) for laminated films mobilities of 0.14 ± 0.03 cm² V^?1 s^?1 independent of alkyl chain length are recorded. Surface‐sensitive near edge X‐ray absorption fine structure (NEXAFS) spectroscopy measurements indicate a strong out‐of‐plane orientation of the polymer backbone at the original air/film interface while much lower average tilt angles of the polymer backbone are observed at the SiO₂/film interface. A comparison with NEXAFS on crystalline P3AT nanofibers, as well as molecular mechanics and electronic structure calculations on ideal P3AT crystals suggest a close to crystalline polymer organization at the P3AT/air interface of films from CB. These results emphasize the negative influence of wrongly oriented polymer on charge carrier mobility and highlight the potential of the polymer/air interface in achieving excellent “out‐of‐plane” orientation and high FET mobilities.     

红外焦平面组件封装中的皮秒激光划片工艺(上)

在对皮秒激光划片加工所涉及的基本原理和设备进行简单介绍的基础上,对红外焦平面组件封装中常涉及的一些材料的特点及其与皮秒激光束的作用机理进行了梳理。通过优化激光参数设置提高了划片效率并保证了划片质量;通过改进工夹具避免了金属层损伤且改善了操作方便性。     

频谱分析中的微分法与微分方程法

本文讨论了应用于傅里叶变换的微分性质的隐含假设,并叙述了信号不满足隐含假设时的修正方法。本文还给出了作为信号生成系统的微分方程描述,它使信号谱成为其生成系统的频率传递函数,指出了微分方程法的隐含假设。最后还给出了信号违反此假设时进行修正的方法。     

A Survey on IP Watermarking Techniques

Intellectual property (IP) block reuse is essential for facilitating the design process of system-on-a-chip. Sharing IP designs poses significant high security risks. Recently, digital watermarking emerged as a candidate solution for copyright protection of IP blocks. In this paper, we survey and classify different techniques used for watermarking IP designs. To this end, we defined several evaluation criteria, which can also be used as a benchmark for new IP watermarking developments. Furthermore, we established a comprehensive set of requirements for future IP watermarking techniques.