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51.
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Breaking the Limits of Ionic Liquid‐Based Supercapacitors: Mesoporous Carbon Electrodes Functionalized with Manganese Oxide Nanosplotches for Dense,Stable, and Wide‐Temperature Energy Storage 下载免费PDF全文
Feili Lai Jianrui Feng Runyu Yan Gui‐Chang Wang Markus Antonietti Martin Oschatz 《Advanced functional materials》2018,28(36)
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. 相似文献
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Chen-Wei Huang Ping Gui Yanli Fan Mark Morgan 《Analog Integrated Circuits and Signal Processing》2012,72(1):89-95
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. 相似文献
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Performance of DS SS system under on-off wideband jamming 总被引:1,自引:0,他引:1
Xiang Gui Tung Sang Ng 《Electronics letters》1997,33(7):557-559
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 相似文献
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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. 相似文献
58.
Yao Zu Liao Veronica Strong Yue Wang Xin‐Gui Li Xia Wang Richard B. Kaner 《Advanced functional materials》2012,22(4):726-735
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. 相似文献
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电气自动化技术术语电气工程中比较常用的技术之一,通过自动控制与检测功能的有效结合来实现对电气系统控制的适时调节与管理,达到电气系统的安全稳定性.近几年来,我国的电气自动化技术得到突破性的创新,使我国电气系统的自动化程度明显提高.如何进一步提升电气自动化技术的发展是目前研究电气自动化技术的重点. 相似文献