山水城市之中国理念

在未来的城市设计中，遵循生态原则是必然的趋势，而山水城市正是生态规划思想以及中国传统理念在城市规划和城市设计中的体现，是城市生态环境可持续发展的中国方式，山东城市集中反映了人们所追求的人与自然相和谐的理想境界，体现了中国传统的“天人合一”的自然观。     

用于便携式健康监护设备的低功耗、低噪声模拟前端电路

本文介绍的用于处理人体生物电信号的模拟前端电路包括仪表放大器、滤波器和可变增益、带宽放大器。仪表放大器采用电容耦合输入来消除直流电极失调。基于电流反馈拓扑结构的IA通过在输入和反馈网络中采用电容分压器来降低功耗。并且,仪表放大器的输入差分对采用互补CMOS输入来提高输入跨导以减小等效输入热噪声。该电路采用Global Foundry 0.35微米 CMOS 工艺流片,电路消耗的总电流为3.96uA,电源电压为3.3V。测试得到的等效输入噪声是0.85uVrms(0.5-100Hz), 噪声能效因子值为6.48。     

完全学分制下工程实训开放式教学管理模式研究与实践

完全学分制教学管理制度是我国高等教育的发展趋势,工程实训是高等院校培养学生工程实践能力和综合创新能力的重要实践性教学课程。文章在分析完全学分制和工程实训教学特点的基础上,提出建设开放式工程实训教学模式是实现工程实训与完全学分制教学管理体制有机结合的唯一途径。通过分析在应用完全学分制下工程训练教学模式中存在的难题和不足,提出了建立完全学分制下开放式工程训练教学模式的方案和实施过程,解决了多数高校工程实训教学中应用完全学分制遇到的难题。     

风力机叶片制造误差对功率和推力影响的量化研究

为量化叶片制造误差对风力机功率和推力的影响,以NREL Phase VI S809风力机叶轮为研究对象,基于区间分析法和修正叶素动量理论,建立风力机不确定气动响应模型,量化弦长扭角制造误差对功率和推力影响的相对波动幅度,采用极差分析法进行敏感性分析,获得不确定影响敏感位置。结果表明,叶片扭角误差对性能影响更为显著;当弦长误差和扭角误差为±0.02c和±0.6°时,功率和推力最大相对波动达到3.26%和8.09%;弦长误差影响敏感位置为叶根,而扭角误差敏感位置为叶尖,可在此部位施加质量参数要求以控制性能偏差。     

动态主用户流量模型的跨层优化设计

为适应主用户流量变化较快的场景,在不完美频谱感知的情况下最大化认知用户的吞吐量,提出了一种基于集中式Overlay认知无线网络中感知时间与资源分配跨层优化算法。将优化目标分解为信道分配和检测时间同功率分配联合优化两个子问题,通过子算法迭代,最终得到感知时间与资源分配的联合最优解。仿真结果表明,相对于仅考虑频谱感知或资源分配的单层优化算法,该算法可在兼顾公平的前提下使次用户吞吐量得到有效提升。     

Digital video steganalysis by subtractive prediction error adjacency matrix

Video has become an important cover for steganography for its large volume. There are two main categories among existing methods for detecting steganography which embeds in the spatial domain of videos. One category focuses on the spatial redundancy and the other one mainly focuses on the temporal redundancy. This paper presents a novel method which considers both the spatial and the temporal redundancy for video steganalysis. Firstly, model of spread spectrum steganography is provided. PEF (Prediction Error Frame) is then chosen to suppress the temporal redundancy of the video content. Differential filtering between adjacent samples in PEFs is employed to further suppress the spatial redundancy. Finally, Dependencies between adjacent samples in a PEF are modeled by a first-order Markov chain, and subsets of the empirical matrices are then employed as features for a steganalyzer with classifier of SVM (Support Vector Machine). Experimental results demonstrate that for uncompressed videos, the novel features perform better than previous video steganalytic works, and similar to the well-known SPAM (Subtractive Pixel Adjacency Model) features which are originally designed for image steganalysis. For videos compressed with distortion, the novel features perform better than other features tested.     

Eradication of Multi‐Drug Resistant Bacteria by a Novel Zn‐doped CuO Nanocomposite

Zinc‐doped copper oxide nanoparticles are synthesized and simultaneously deposited on cotton fabric using ultrasound irradiation. The optimization of the processing conditions, the specific reagent ratio, and the precursor concentration results in the formation of uniform nanoparticles with an average size of ≈30 nm. The antibacterial activity of the Zn‐doped CuO Cu_0.88Zn_0.12O in a colloidal suspension or deposited on the fabric is tested against Escherichia coli (Gram negative) and Staphylococcus aureus (Gram positive) bacteria. A substantial enhancement of 10 000 times in the antimicrobial activity of the Zn–CuO nanocomposite compared to the pure CuO and ZnO nanoparticles (NPs) is observed after 10 min exposure to the bacteria. Similar activities are observed against multidrug‐resistant bacteria (MDR), (i.e., Methicillin‐resistant S. aureus and MDR E. coli) further emphasizing the efficacy of this composite. Finally, the mechanism for this enhanced antibacterial activity is presented.     

基于深度神经网络的Morse码自动译码算法

在军用和民用领域,Morse电报一直是一种重要的短波通信手段,但目前的自动译码算法仍然存在准确率低、无法适应低信噪比和不稳定的信号等问题。该文引入深度学习方法构建了一个Morse码自动识别系统,神经网络模型由卷积神经网络、双向长短时记忆网络和连接时序分类层组成,结构简单,且能够实现端到端的训练。相关实验表明,该译码系统在不同信噪比、不同码速、信号出现频率漂移以及不同发报手法引起的码长偏差等情况下,均能取得较好的识别效果,性能优于传统的自动识别算法。     

Laser-Induced,Green and Biocompatible Paper-Based Devices for Circular Electronics

The growing usage and consumption of electronics-integrated items into the daily routine has raised concerns on the disposal and proper recycling of these components. Here, a fully sustainable and green technology for the fabrication of different electronics on fruit-waste derived paper substrate, is reported. The process relies on the carbonization of the topmost surface of different cellulose-based substrates, derived from apple-, kiwi-, and grape-based processes, by a CO₂ laser. By optimizing the lasing parameters, electronic devices, such as capacitors, biosensors, and electrodes for food monitoring as well as heart and respiration activity analysis, are realized. Biocompatibility tests on fruit-based cellulose reveal no shortcoming for on-skin applications. The employment of such natural and plastic-free substrate allows twofold strategies for electronics recycling. As a first approach, device dissolution is achieved at room temperature within 40 days, revealing transient behavior in natural solution and leaving no harmful residuals. Alternatively, the cellulose-based electronics is reintroduced in nature, as possible support for plant seeding and growth or even soil amendment. These results demonstrate the realization of green, low-cost and circular electronics, with possible applications in smart agriculture and the Internet-of-Thing, with no waste creation and zero or even positive impact on the ecosystem.