关于MPEG-2空域时域自适应错误隐藏算法

MPEG-2的压缩算法,由于采用可变字长编码使得其对信道错误十分敏感,即使单比特错误都有可能导致图像质量的严重下降,使部分或整条信息丢失。在解码端的错误隐藏技术是解决这个问题的有效方法之一。该文基于图像像素间的最大光滑连接,利用丢失宏块的邻域宏块的全部信息,导出了加权内插的错误隐藏公式。提出了一种自适应的错误隐藏方法,序列中的第一帧使用空域信息重构丢失的区域,其它帧使用本文建议的空域时域自适应错误隐藏方法。仿真实验的结果表明本文建议的算法优于一些传统算法。     

超高压力传感器绝缘封装薄膜的工艺研究

为了提高锰铜传感器的测压上限,须用薄膜工艺制备无机绝缘三氧化二铝薄膜来作为传感器的绝缘封装层。采用电子束蒸发法,对影响三氧化二铝薄膜的相关工艺如:蒸发原料的纯度、成膜次数进行了研究。最终得出:由99.99%的三氧化二铝原料制备出的薄膜致密性好、缺陷少,其绝缘电阻率和损耗分别可达1012O·cm和103量级;而采用多次间隙蒸发可明显改善薄膜的附着性和致密性。     

In‐Plane Assembled Orthorhombic Nb2O5 Nanorod Films with High‐Rate Li+ Intercalation for High‐Performance Flexible Li‐Ion Capacitors

Organic hybrid supercapacitors that consist of a battery electrode and a capacitive electrode show greatly improved energy density, but their power density is generally limited by the poor rate capability of battery‐type electrodes. In addition, flexible organic hybrid supercapacitors are rarely reported. To address the above issues, herein an in‐plane assembled orthorhombic Nb₂O₅ nanorod film anode with high‐rate Li⁺ intercalation to develop a flexible Li‐ion hybrid capacitor (LIC) is reported. The binder‐/additive‐free film exhibits excellent rate capability (≈73% capacity retention with the rate increased from 0.5 to 20 C) and good cycling stability (>2500 times). Kinetic analyses reveal that the high rate performance is mainly attributed to the excellent in‐plane assembly of interconnected single‐crystalline Nb₂O₅ nanorods on the current collector, ensuring fast electron transport, facile Li‐ion migration in the porous film, and greatly reduced ion‐diffusion length. Using such a Nb₂O₅ film as anode and commercial activated carbon as cathode, a flexible LIC is designed. It delivers both high gravimetric and high volumetric energy/power densities (≈95.55 Wh kg^?1/5350.9 W kg^?1; 6.7 mW h cm^?3/374.63 mW cm^?3), surpassing previous typical Li‐intercalation electrode‐based LICs. Furthermore, this LIC device still keeps good electrochemical attributes even under serious bending states (30°–180°).     

Mechanical Strain‐Tunable Microwave Magnetism in Flexible CuFe2O4 Epitaxial Thin Film for Wearable Sensors

Purely mechanical strain‐tunable microwave magnetism device with lightweight, flexible, and wearable is crucial for passive sensing systems and spintronic devices (noncontact), such as flexible microwave detectors, flexible microwave signal processing devices, and wearable mechanics‐magnetic sensors. Here, a flexible microwave magnetic CuFe₂O₄ (CuFO) epitaxial thin film with tunable ferromagnetic resonance (FMR) spectra is demonstrated by purely mechanical strains, including tensile and compressive strains, on flexible fluorophlogopite (Mica) substrates. Tensile and compressive strains show remarkable tuning effects of up‐regulation and down‐regulation on in‐plane FMR resonance field (H_r), which can be used for flexible tunable resonators and filters. The out‐of‐plane FMR spectra can also be tuned by mechanical bending, including H_r and absorption peak. The change of out‐of‐plane FMR spectra has great potential for flexible mechanics‐magnetic deformation sensors. Furthermore, a superior microwave magnetic stability and mechanical antifatigue character are obtained in the CuFO/Mica thin films. These flexible epitaxial CuFO thin films with tunable microwave magnetism and excellent mechanical durability are promising for the applications in flexible spintronics, microwave detectors, and oscillators.     

Hierarchically Structured Self‐Healing Sensors with Tunable Positive/Negative Piezoresistivity

It is a challenge to manufacture flexible sensors that possess easily distinguishable biomotion signals, strong response reliability, and excellent self‐healing capability. Herein, a self‐healing sensor with tunable positive/negative piezoresistivity is designed by the construction of hierarchical structure connected through supramolecular metal–ligand coordination bonds. The developed sensors can be integrated with the human body to detect multiple tiny signals, such as pronunciation, coughing, and deep breathing. Interestingly, the nanostructured elastomer sensor with and without a flexible yarn electrode shows negative and positive current signals, respectively, making it easy to be identify. Furthermore, it exhibits very fast (2 min), autonomous, and repeatable self‐healing ability with high‐healing efficiency (88.6% after the third healing process). The healed samples still possess flexibility, high sensitivity, and accurate detection capability, even after bending over 10 000 cycles. The excellent biomimetic self‐healing performance combined with the tunable piezoresistivity make it promising for next‐generation wearable electronics.     

Delay-dependent H∞ filtering for discrete-time singular Markovian jump systems with time-varying delay and partially unknown transition probabilities

This paper is concerned with the H_∞ filtering design for a class of discrete-time singular Markovian jump systems with time-varying delay and partially unknown transition probabilities. The class of systems under consideration is more general and covers the singular Markovian delay systems with completely known and completely unknown transition probabilities as two special cases. A mode-dependent filter is constructed and by defining an appropriate stochastic Lyapunov functional combined with using the discrete Jensen inequality, a delay-dependent bounded real lemma (BRL) for the considered systems is established in terms of linear matrix inequalities (LMIs). Based on this, a sufficient condition on the existence of the desired filter which guarantees the admissibility and the H_∞ performance of the corresponding filtering error system is presented by employing the LMIs technique. Some numerical examples are provided to illustrate the effectiveness of the developed theoretical results.     

An improved LMI-based criterion for the design of optimal guaranteed cost controller for 2-D discrete uncertain systems

An improved criterion for the design of optimal static-state feedback guaranteed cost controller for two-dimensional (2-D) discrete uncertain systems described by the Fornasini-Marchesini second local state-space (FMSLSS) model is proposed. The design problem of the optimal guaranteed cost controller is formulated as a convex optimization problem with linear matrix inequality (LMI) constraints. The proposed method yields tighter upper bound of the closed-loop cost function as compared to a recently reported method.     

Electrical characteristics and TDDB breakdown mechanism of N2-RTA-treated Hf-based high-κ gate dielectrics

This study investigates the effects of rapid thermal annealing (RTA) in nitrogen ambient on HfO₂ and HfSiO_x gate dielectrics, including their electrical characteristics, film properties, TDDB reliability and breakdown mechanism. The optimal temperature for N₂ RTA treatment is also investigated. The positive oxide trap charges (oxygen vacancies) in HfO₂ and HfSiO_x dielectric films can be reduced by the thermal annealing, but as the annealing temperature increased, many positive oxide trap charges (oxygen vacancies) with shallow or deep trap energy level will be formed in the grain boundaries, degrading the electrical characteristics, and changing the breakdown mechanism. We believe that variation in the number of positive oxide trap charges (oxygen vacancies) with shallow or deep trap energy levels is the main cause of the CV shift and difference in the breakdown behaviors between HfO₂ and HfSiO_x dielectrics. With respect to CV characteristics and TDDB reliability, the optimal temperature for N₂ RTA treatment is in the range 500-600 °C and 800-900 °C, respectively.     

基于不同介质材料的AOTF特性研究综述

基于不同介质材料的AOTF(声光可调谐滤波器)具有不同的性质及应用场合.目前应用于紫外、可见光和红外波段的AOTF主要以α-SiO2、TeO2和TAS( Tl3AsSe3)为介质.为了得到性能更优的AOTF,人们一直在探寻新型双折射晶体材料来代替α-SiO2和TAS.文章汇总并讨论了近年来人们针对基于TeO2、KDP(...     

电子束沉积In2O3基W-Mo共掺薄膜的特性研究

利用电子束反应沉积技术制备了高迁移率I2O3基W-Mo共掺(IMWO,I<,2>O<,3>:WO<,3>/MoO<,3>)薄膜,研究了不同等量WO<,3>-MoO<,3>掺杂浓度对薄膜的微观结构、光学性能和电学性能的影响.IMWO薄膜的表面形貌呈现"类金字塔"型.随着WO<,3>-MoO<,3>共掺量的增加,IMWO薄...