Breaking the Limits of Ionic Liquid‐Based Supercapacitors: Mesoporous Carbon Electrodes Functionalized with Manganese Oxide Nanosplotches for Dense,Stable, and Wide‐Temperature Energy Storage

Manganese oxide (MnO₂) nanosplotches (NSs) are deposited on N‐ and S‐doped ordered mesoporous carbon (N,S‐CMK‐3) essentially blocking microporosity. The obtained N,S‐CMK‐3/MnO₂ composite materials are assembled into ionic liquid (IL)‐based symmetric supercapacitors, which exhibit a high specific capacitance of 200 F g^?1 (0–3.5 V) at a scan rate of 2 mV s^?1, and good rate stability with 55.5% capacitance retention at a scan rate of 100 mV s^?1. The device can operate in a wide temperature range (?20 to 60 °C), and high cycling stability of N,S‐CMK‐3/MnO₂ composite electrode is demonstrated. Lower energy of ?3.56 eV can be achieved for the adsorption of 1‐ethyl‐3‐methylimidazolium⁺ (EMIM⁺) cation on the edge between MnO₂ NSs and N,S‐CMK‐3 than on the plane of MnO₂ NS (?3.04 eV), both being more preferred than the surface of pristine N,S‐CMK‐3 (?1.52 eV). This strengthening of the ion adsorption at the three‐phase boundary between N,S‐CMK‐3, MnO₂, and IL leads to enhancement of the specific capacity as compared to nondoped or MnO₂‐free reference materials. Supercapacitors based on such composite electrodes show significantly enhanced areal capacity pointing to energy storage in the mesopores rather than in the electrochemical surface layer, demonstrating a new energy storage mechanism in ILs.     

低压静止无功发生器的实验研究

静止无功发生器已经成为系统电压调整和无功补偿的重要设备。本文在简单分析SVG基本原理的基础上，介绍了无功补偿原理，提出了具体的硬件设计和软件设计，并进行了相关的实验。取得了部分实验波形。验证了SVG的补偿作用。     

基于光离子化技术的气体检测系统设计与实现

针对航空领域大型作业场所需要连续检测低浓度气体浓度的任务,设计了一种基于光离子化技术的气体检测系统。该系统以FPGA为控制芯片,采用光离子化技术,实现连续检测低浓度气体浓度的功能,同时因其响应速度快,使用更加方便。该系统对1×10^-6~200×10^-6浓度的异丁烯和乙烯、丙烯和二甲醚气体进行测试,结果表明,基于光离子化技术的气体检测系统能够在3 s内检测低浓度气体的浓度,分辨率为2×10^-6,同时自身具备防护能力,能够适应电磁干扰、强冲击等恶劣环境。     

高分辨率SAR图像目标峰值特征提取

峰值特征是进行SAR图像自动目标识别的重要特征。本文提出了SAR图像目标的通用高斯峰值模型,根据该模型提出了目标峰值提取方法。利用实测数据以及蒙特卡罗仿真结果表明:通用高斯峰值模型是实际峰值的一种精确模型,基于该模型的峰值提取方法具有良好的提取精度。     

An instant-switching ?–Σ fractional-N frequency synthesizer with adjustable duty cycles

A Phase-Locked Loop (PLL)-based frequency synthesizer (FS) with adjustable duty cycle is presented. By employing digital processing circuitry and the ??C?? fractional-N technique, the FS is capable of generating arbitrary frequencies in a wide frequency range, and capable of adjusting the clock duty cycles. In addition, the switching between different frequencies is instant except when a very fine frequency resolution is required. The adjustable duty cycle and instant switching are desired features in applications such as time-interleaved Analog-to-Digital-Converters (ADCs), switched-capacitor circuits, and DC?CDC converters. The design was fabricated using a 0.13???m CMOS process. This paper gives the theories, analysis, implementation, and measurement results of this FS.     

金刚石薄膜的反应离子刻蚀

反应离子刻蚀是金刚石薄膜图形化的一种有效方法。研究了用Ｏ２及与Ａｒ的混合气体进行金刚石薄膜图形化刻蚀的主要工艺参数（射频功能、工作气压、气体流量、反应气体成分与比例等）对刻蚀速率和刻蚀界面形貌的影响，兼顾刻蚀速率和刻蚀平滑程度等关键因素，建立了金刚石薄膜刻蚀的优化工艺参数，达到了较满意的图形效果。     

Performance of DS SS system under on-off wideband jamming

A performance analysis of a direct sequence spread spectrum (DS SS) system under a periodic on-off wideband jammer is presented. Closed-form results of system bit error rate (BER) are derived for all possible cases of jammer duty cycle     

基于干涉图幅度和相位联合的双通道SAR地面慢动目标检测方法

提出了一种基于干涉图幅度和相位联合的双通道合成孔径雷达(SAR, Synthetic Aperture Radar)地面慢动目标检测方法.在干涉图幅度、相位统计特性分析基础上,充分利用动目标像素点和杂波干扰之间的散射特性差异,通过对干涉图相位进行函数变换,并联合干涉图幅度得到了一种新的动目标检测量,由该检测量并结合邻域平均处理可以较容易地实现动目标的快速精确检测.仿真实验表明:所提检测算法与经典的DPCA(Displaced Phase Center Antenna)、ATI(Along Track Interferometry)方法相比,具有杂波和噪声抑制能力强、稳健性高、适用范围广、可检测速度范围大、检测率高、虚警率低等特点,证明了算法的有效性.     

10Gbit/s高T0无制冷分布反馈激光器

与折射率耦合分布的分布反馈（DFB）激光器相比,不管界面反射率是多少,增益耦合DFB激光器都能稳定地单纵模工作,而且具有高速、低啁啾的特性．本课题组用AlGaInAs/InP材料,采用增益耦合DFB结构,进行了单纵模激光器研发,并对器件特性进行了测试分析．     

Oligotriphenylene Nanofiber Sensors for Detection of Nitro‐Based Explosives

Blue light‐emitting oligotriphenylene nanofibers are synthesized by oxidizing triphenylene using ferric chloride. By adjusting the monomer concentration, the acid used, and the temperature employed, the average diameter and length of the nanofibers can be readily tuned from 50 to 200 nm and 0.5 to 5 μm, respectively. Structural characterization, electrical conductivity, thermal stability, and fluorescence of oligotriphenylene, along with a proposed nanofiber formation mechanism, are presented. Both oligotriphenylene nanofiber dispersions and oligotriphenylene/polysulfone composite films are developed as fluorescent sensors for detecting traces of nitro‐based explosives including nitromethane, nitrobenzene, and 2,4,6‐trinitrophenol, as well as an electron‐deficient metal ion, Fe(III). The sensors exhibit much better selectivity and sensitivity compared to conventional sensors, with detection limits down to 1.0 nm with a detection range covering ～4 orders of magnitude. The detection mechanism of the fluorescent sensors is also disscussed.