PMD Measurement of Hollow-Core Photonic Bandgap Fiber by Investigating Power Penalty of Optically Generated Microwave Signals

A simple method based on carrier suppression modulation for measuring first-order polarization-mode dispersion of hollow-core photonic bandgap fiber (HC-PBGF) is proposed and investigated. By adjusting the incident optical wavelength and measuring the power penalty of optically generated microwave signals, the wavelength-dependent differential group delay (DGD) in HC-PBGF can be obtained. Moreover, this proposed method is chromatic-dispersion-insensitive. The experimental results indicate that a segment of 20-m HC-PBGF exhibits highly birefringent DGD of 25, 59, and 84 ps with measurement error less than 2 ps for the incident optical wavelength of 1560, 1575, and 1580 nm, respectively     

Detection of sudden pedestrian crossings for driving assistance systems

In this paper, we study the problem of detecting sudden pedestrian crossings to assist drivers in avoiding accidents. This application has two major requirements: to detect crossing pedestrians as early as possible just as they enter the view of the car-mounted camera and to maintain a false alarm rate as low as possible for practical purposes. Although many current sliding-window-based approaches using various features and classification algorithms have been proposed for image-/video-based pedestrian detection, their performance in terms of accuracy and processing speed falls far short of practical application requirements. To address this problem, we propose a three-level coarse-to-fine video-based framework that detects partially visible pedestrians just as they enter the camera view, with low false alarm rate and high speed. The framework is tested on a new collection of high-resolution videos captured from a moving vehicle and yields a performance better than that of state-of-the-art pedestrian detection while running at a frame rate of 55 fps.     

磷石膏的微量组分及其对水泥凝结、水化和硬化的影响

借助差热分析、热失重、X射线衍射和扫描电镜等测试手段,分析了磷石膏的微量组分,研究了磷石膏对硅酸盐水泥物理性能及水化过程和水化产物的影响,进而探讨了磷石膏对水泥单矿物的水化作用机理。     

两种高压直流电源的比较及在铜冶炼烟气制酸装置电除雾器中的应用

论述恒压源与恒流源两种高压直流电源的工作原理和技术特点.对两种电源常见故障的原因进行分析，提出相应的解决方法。介绍两种电源在230kt／a诺兰达炉冶炼烟气和270kt／a转炉冶炼烟气制酸装置的电除雾器中的使用情况.     

汽车制动管路压力波动响应特性仿真

阐述了汽车制动管路波动负载发生装置的基本结构和原理,描述了汽车制动管路波动负载发生装置的AMESim模型以及在仿真中用到的模型参数。利用仿真模型研究了制动液体积弹性模量等主要参数对制动管路压力波动响应特性的影响,研究结果为ABS系统与整车制动系统的匹配提供了重要依据。     

基于PCA-Logistic模型的围岩稳定性分类研究

为了建立易于理解和应用的围岩稳定性分类模型,采用主成分分析法对围岩样本数据进行降维处理,以Logistic模型来描述围岩稳定性影响因素与围岩稳定性之间的经验关系。选取影响围岩分类的5个主要因素,根据分类标准,采用在每级标准中随机内插的方法,得到100个标准样本,用于建立PCA-Logistic模型。分析结果显示,PCA-Logistic模型拟合效果良好,对工程实例的预测结果同投影寻踪模型和分形-插值模型完全一致,表明该模型在围岩稳定性评价中具有可行性和有效性。     

一种基于C#的通用软件安装程序的架构设计与实现

可以说每个商业化软件都必须具备安装工具,使用系统软件自带的打包程序有时很难满足实际需求,为此提出了一种基于C#的通用软件安装程序的架构,给出了实现这一架构的设计方法和关键代码.通过该架构,可以非常容易地实现安装程序的功能扩展和代码维护.     

基于校园GIS环境的排课系统设计研究

结合学校实际情况和发展现状,提出基于校园GIS环境的排课系统设计方法,在传统的字符信息中融入空间地理信息,对排课问题中的各种约束条件进行分析,通过设定合理的排课原则和优先级,完成课程的编排,同时实现以校园GIS为基础的可视化的信息管理功能。     

A Stable Polymer-based Solid-State Lithium Metal Battery and its Interfacial Characteristics Revealed by Cryogenic Transmission Electron Microscopy

Solid-state lithium metal batteries (SSLMBs) are a promising candidate for next-generation energy storage systems due to their intrinsic safety and high energy density. However, they still suffer from poor interfacial stability, which can incur high interfacial resistance and insufficient cycle lifespan. Herein, a novel poly(vinylidene fluoride‑hexafuoropropylene)-based polymer electrolyte (PPE) with LiBF₄ and propylene carbonate plasticizer is developed, which has a high room-temperature ionic conductivity up to 1.15 × 10⁻³ S cm⁻¹ and excellent interfacial stability. Benefitting from the stable interphase, the PPE-based symmetric cell can operate for over 1000 h. By virtue of cryogenic transmission electron microscopy (Cryo-TEM) characterization, the high interfacial compatibility between Li metal anode and PPE is revealed. The solid electrolyte interphase is made up of an amorphous outer layer that can keep intimate contact with PPE and an inner Li₂O-dominated layer that can protect Li from continuous side reactions during battery cycling. A LiF-rich transition layer is also discovered in the region of PPE close to Li metal anode. The feasibility of investigating interphases in polymer-based solid-state batteries via Cryo-TEM techniques is demonstrated, which can be widely employed in future to rationalize the correlation between solid-state electrolytes and battery performance from ultrafine interfacial structures.     

N-polar GaN基HEMT准二维电荷传输模型仿真

建立了氮极性(N-polar)GaN基HEMT器件的准二维(Quasi-2-D)电荷传输模型,仿真研究了N-polar GaN基HEMT的直流特性。仿真结果表明,不同的极化效应会对输出特性曲线和转移特性曲线产生不同的影响,考虑自发极化效应(Psp)+压电极化效应(Ppe)、只考虑Ppe和只考虑Psp三种情况下的阈值电压分别为:-3.96V、-2.29V和-2.47V,而其对应的峰值跨导则分别为44mS/mm、41.2mS/mm和41.3mS/mm。该模型为N-polar GaN基HEMT器件仿真提供了理论参考。