压电微马达研究进展

利用网络和图书馆对国际上1996年至今的压电微马达研究进展进行了调研。分别介绍了压电薄膜陶瓷的行波、驻波类微马达的最新研究情况，同时也对一种具有与压电微马达特性相同的静电超声微马达的研究作了说明，最后给出了本实验室研制的压电陶瓷行波微马达的运动机理。     

模糊控制理论在雷达天控系统中的应用

论述了模糊控制器在雷达天控系统中应用的可行性，分析并比较出几种二维模糊控制器的性能，从中选出较好的控制方案。研究证明，模糊控制器应用在天控系统中，可大大改善系统的性能指标。     

丙丁烷TDLAS测量系统的吸收峰自动检测

基于丙丁烷在3.37μm处的基频吸收峰,使用相应中心波长的连续带间级联激光器和长光程吸收池,研制了基于波长调制技术的丙丁烷气体检测系统。为自动确定波长调制过程中的锯齿波中心值参数,基于电流与输出光频率的线性关系,通过均匀增加激光器驱动电流获得直接吸收光谱。使用基于洛伦兹线型的拟合算法确定吸收峰值对应电流,使锯齿波输出光以其为中心覆盖吸收峰。实验证明,以拟合结果31.94mA为中心值的锯齿波,在叠加频率为20 000Hz、幅值为0.03V的高频正弦调制波后,系统二次谐波峰值超过100mV。算法全过程不依赖标气和F-P标准具等精密光学器件,可适应实际生产条件下的系统自动定参。     

Responsive Smart Windows from Nanoparticle–Polymer Composites

Windows play significant roles in commercial and residential buildings and automobiles, which direct and control light illumination, thermal insulation, natural ventilation, and aesthetics. Various approaches are attempted to make windows “smart” by tailoring their transparency and thermal insulation in response to environmental changes. Hence, there has been much effort to develop smart windows that can dynamically modulate the transmission and reflectance of the visible light and solar radiance into buildings according to weather conditions or personal preferences. Development of smart window materials is also beneficial to applications including wearable sensors, energy harvesting and storage, and medical devices. By carefully matching the refractive indices of nanoparticle (NPs) and polymer matrix, surface chemistry, and their mechanical properties, particle‐embedded polymer composites can exhibit synergistic effects with improved chemical and mechanical stability, enhanced dispersion of NPs, and optimized and stimuli‐responsive optical properties. Here, an overview of recent progresses in the development of smart windows based on electro‐, thermo‐, and mechanoactuations is provided. Additional functionalities, e.g., flexibility, stretchability, and mechanical/chemical stability, can also be achieved by careful choices of NPs and polymers.     

Response Time in Data Broadcast Systems: Mean,Variance and Tradeoff

Data broadcast has been suggested as a promising method of information dissemination [2,33]. In such an environment, the information server cannot afford to serve the requests from a large population of users individually. Instead, the server uses a broadcast channel to deliver information to all users. A single transmission of a data item satisfies all pending requests for that item. The response time of a request depends on the broadcast time of the desired data item, which is scheduled by the server according to the overall demands for various data items. Therefore, the response time may vary in a large range. We argue that, in addition to mean response time, the variance of response time should also be taken into account by the broadcast scheduler. In this paper, we address the issue of variance optimization in regard to response time. Building on our previous research on mean response time optimization, we propose an algorithm which can minimize the variance of response time. Furthermore, we evaluate an algorithm that facilitates a tradeoff between the mean and variance of response time. Numerical examples that illustrate the performance of our algorithms are also presented.     

Harmonically mode-locked fiber laser with optically selectablewavelength

In this letter, we demonstrate optical selection of wavelength in a harmonically mode-locked fiber laser that incorporates a semiconductor optical amplifier nonlinear fiber loop. Wavelength tuning is achieved by controlling the delay time between the modulation and the control signals in the compensated dispersion-tuning scheme. A tuning range over 19 nm is obtained. The power suppression of nonlasing modes reaches a maximum of 34 dB. The output wavelength and the delay time are governed by a linear relationship     

基于后向ASE抽运的L-波段掺铒光纤放大器

利用后向ASE抽运一段未抽运光纤和一段不完全抽运光纤两种结构 ,实现了EDFA自发辐射谱向长波方向移动 ,分别得到了 3dB带宽为 5 6 3nm和 4 7 6nm的L 波段自发辐射谱 ,对 1 5 75nm输入信号 (强度为 - 3 0dBm)的增益分别为 3 5dB和 9 2dB     

纹理分析在生物组织光学相干层析图像信息提取和特征识别中的应用

随着光学相干层析(OCT)技术在生物医学成像领域日趋广泛的应用,分析和提取OCT图像中所包含的生物组织信息、对相关特征加以识别,并最终应用于疾病的辅助诊断和诊疗效果的追踪,已经成为一个重要的研究方向.国内外研究者就此提出了多种不同的方法,其中纹理分析方法得到了最为充分的研究,显示出良好的实用性.对纹理分析在生物组织光学...     

One‐Pot Synthesis of Framework Porphyrin Materials and Their Applications in Bifunctional Oxygen Electrocatalysis

Organic framework materials constructed by covalently linking organic building blocks into framework structures are highly regarded as paragons to precisely control the material structure at the atomic level. Herein, a direct synthesis methodology is proposed as a guidance for the bulk synthesis of organic framework materials. Framework porphyrin (POF) materials are one‐pot synthesized to demonstrate the advances of the direct synthesis methodology. The as‐synthesized POF materials are intrinsically 2D and exhibit impressive versatility in composition, structure, morphology, and function, delivering a free‐standing POF film, hybrids of POF and nanocarbon, and cobalt‐coordinated POF. When applied as electrocatalysts for oxygen reduction reaction and oxygen evolution reaction, the cobalt‐coordinated POF exhibits excellent bifunctional electrocatalytic performances comparable with noble‐metal‐based electrocatalysts. The direct synthesis methodology and resultant POF materials demonstrate the ability of controlling materials at the atomic level for energy electrocatalysis.     

基于S3C2410型微处理器和UDA1341型立体声音频编解码器的嵌入式音频系统设计

S3C2410是Samsung公司一款基于ARM920T核的微处理器,通过IIS音频总线与UDA1341型CODEC构成一种嵌入式音频系统,实现音频的播放和采集.给出相关硬件电路的说明及Linux下音频驱动程序的设计要点.