微课在“Java程序设计”教学中的应用研究

近些年来,国家教育事业正在发展前行中,受到高度的重视。国家社会的发展需要很多优秀的人才资源,国家也不断地加强教学体制的改革,逐渐地提升了高职教学的要求。文章主要就微课在“Java程序设计”教学中的应用,进行一些相关阐述。     

基于三维卷积的帕金森患者拖步识别

冻结步态(FoG)是一种在帕金森病(PD)中常见的异常步态,而拖步则是冻结步态的一种表现形式,也是医生用来判断患者的治疗状况的重要因素,并且拖步状态也对PD患者的日常生活有很大影响。该文提出一种通过计算机视觉来实现患者拖步状态自动识别的方法,该方法通过以3维卷积为基础的网络结构,可以从PD患者的TUG测试视频中自动识别出患者是否具有拖步症状。其思路是首先利用特征提取模块从经过预处理的视频序列中提取出时空特征,然后将得到的特征在不同空间和时间尺度上进行融合,之后将这些特征送入分类网络中得到相应的识别结果。在该工作中共收集364个正常步态样本和362个具有拖步状态的样本来构成实验数据集,在该数据集上的实验表明,该方法的平均准确率能够达到91.3%。并且其能从临床常用的TUG测试视频中自动准确地识别出患者的拖步状态,这也为远程监测帕金森病患者的治疗状态提供了助力。     

氧化后退火技术对SiO2/4H-SiC界面态密度的影响

采用等离子体增强化学气相沉积(PECVD)低温处理和高温快速退火的技术,研究了退火条件对SiO2/4H-SiC界面态密度的影响.在n型4H-SiC外延片上高温干氧氧化50 nm厚的SiO2层并经N2原位退火,随后在PECVD炉中对样品进行350℃退火气氛为PH3,N2O,H2和N2的后退火处理,之后进行高温快速退火,最后制备Al电极4H-SiC MOS电容.I-V和C-V测试结果表明,各样品的氧化层击穿场强均大于9 MV/cm,PH3处理可以降低界面有效负电荷和近界面氧化层陷阱电荷,但PH3处理样品的界面态密度比N2O处理的结果要高.经N2O氛围PECVD后退火样品在距离导带0.2和0.4 eV处的界面态密度分别约为1.7× 1012和4×1011eV-1·cm-2,有望用于SiC MOSFET器件的栅氧处理.     

基于多层字典的自重构目标跟踪算法

针对视觉跟踪系统中常用的模板处理方法很难 适应目标外观和视频背景不断变化的不足,提出一种基于多层字典的自重构 目标跟踪算法。通过构建多层字典,分别从时间和 空间上增强目标描述能力,既可以刻画目标局部细节,又蕴含了目标整体信息;在跟踪过程 中,模板可以利 用多层字典根据前景和背景的复杂性自适应地分裂与分并,分裂出多个跟踪器从不同角度进 行跟踪,有效地 提高定位精度,也可以合并子模板以达到降低系统的计算负荷。定性和定量分析的实验结果 表明,本文算法具 有良好的跟踪精度和运行效率,可以较好地应对变化与遮挡。     

Outage Probability Analysis for Energy Harvesting Cooperative Relays in a Clustered Environment

This paper presents the outage probability analysis of the energy harvesting (EH) decode and forward (DF) cooperative relay network when more than one relays are available to assist the communication between source and destination in the presence of the direct connection. The relays use power splitting (PS) protocol with adaptive PS ratio for EH. As wireless EH can be more beneficial over smaller distances therefore a clustered environment is considered in which the source, destination and relays are located in a small area. First, we analyze the performance of selection cooperation (SC) which requires channel state information (CSI) at the source. High signal to noise ratio approximation of the outage probability is provided for this case. Secondly, we present the performance of all relays cooperation (ARC) scheme which requires no CSI at the source. Lower and upper bounds of the outage probability are presented for smaller number of relays in ARC scheme whereas high signal to noise ratio approximation is provided for higher number of relays. Simulation results validate the analytical results and show that SC scheme outperforms ARC scheme at the expense of CSI requirement.     

PFM开关电源集成电路的抗电磁干扰设计

针对脉冲频率调制(PFM)开关电源(SMPS)集成电路,提出了抗电磁干扰(EMI)设计的两种方法.通过采用零电流检测电路,控制开关电源集成电路中的开关金属氧化物半导体场效应晶体管(MOSFET)在第一个谷底导通,从而降低导通电流的尖峰值.通过采用恒压和恒流设计技术,使开关电源集成电路中的电压和电流得到限制,有助于降低电流纹波.采用CSMC lμm 40 V高压工艺设计了PFM开关电源集成电路SX1618,将以上两种抗电磁干扰设计方法应用在该电路的设计中,并设计了针对性的保护结构.完成SX1618整体仿真和版图设计后进行了流片和封装,并将其应用在实际的开关电源中,经测试,开关电源的抗电磁干扰能力符合标准.     

Wearable Force Touch Sensor Array Using a Flexible and Transparent Electrode

Transparent electrodes have been widely used for various electronics and optoelectronics, including flexible ones. Many nanomaterial‐based electrodes, in particular 1D and 2D nanomaterials, have been proposed as next‐generation transparent and flexible electrodes. However, their transparency, conductivity, large‐area uniformity, and sometimes cost are not yet sufficient to replace indium tin oxide (ITO). Furthermore, the conventional ITO is quite rigid and susceptible to mechanical fractures under deformations (e.g., bending, folding). In this study, the authors report new advances in the design, fabrication, and integration of wearable and transparent force touch (touch and pressure) sensors by exploiting the previous efforts in stretchable electronics as well as novel ideas in the transparent and flexible electrode. The optical and mechanical experiment, along with simulation results, exhibit the excellent transparency, conductivity, uniformity, and flexibility of the proposed epoxy‐copper‐ITO (ECI) multilayer electrode. By using this multi‐layered ECI electrode, the authors present a wearable and transparent force touch sensor array, which is multiplexed by Si nanomembrane p‐i‐n junction‐type (PIN) diodes and integrated on the skin‐mounted quantum dot light‐emitting diodes. This novel integrated system is successfully applied as a wearable human–machine interface (HMI) to control a drone wirelessly. These advances in novel material structures and system‐level integration strategies create new opportunities in wearable smart displays.     

Chemically Functionalized Natural Cellulose Materials for Effective Triboelectric Nanogenerator Development

Cellulose, the most abundant natural polymer, is renewable, biodegradable, and cost competitive. This paper reports the development of a high‐performance triboelectric nanogenerator (TENG) with both contacting materials made from cellulosic materials. Cellulose nanofibrils (CNFs) are used as the raw material, and chemical reaction approaches are employed to attach nitro groups and methyl groups to cellulose molecules to change the tribopolarities of CNF, which in turn significantly enhances the triboelectric output. Specifically, the nitro‐CNF possesses a negative surface charge density of 85.8 µC m^?2, while the methyl‐CNF possesses a positive surface charge density of 62.5 µC m^?2, reaching 71% and 52% of that for fluorinated ethylene propylene (FEP), respectively. The figure of merit of the nitro‐CNF and methyl‐CNF is quantified to be 0.504 and 0.267, respectively, comparable to or exceeding a number of common synthetic polymers, such as Kapton, polyvinylidene fluoride, and polyethylene. The TENG fabricated from nitro‐CNF paired with methyl‐CNF demonstrates an average voltage output of 8 V and current output of 9 µA, which approaches the same level obtained from TENG made from FEP. This work demonstrates a successful strategy of using environmentally friendly, abundant cellulosic materials for replacing the synthetic polymers in TENG development.