表面肌电信号采集仪的软硬件设计

针对表面肌电信号幅度小、信噪比低、易受干扰、准确获取困难的问题,研制一种基于高共模抑制比的前端放大电路的便携式表面肌电信号采集仪,包含肌电采集放大、AD转换、带触摸屏的液晶显示、数据存储、USB有线传输、Xbee无线传输等多个组成部分。采用μC/OS-Ⅱ操作系统和基于μC/GUI的图形化界面,性能稳定,操作简便。同时,为了方便用户资料及肌电数据的管理,移植了FATFS文件系统。低功耗和微型化设计提高了设备的便携性,有利于提高表面肌电信号采集仪在运动员训练中的使用率。     

基于相量量测的等式约束二阶段状态估计模型

利用PMU的量测信息实现系统的动态可观测,考虑PMU数据刷新时间快的特点,在R.F.Nuqui的动态监测模型的基础上建立了适合静态估计的基于等式约束二阶段估计模型。该模型将PMU和SCADA的量测数据共同用于非线性估计,采用零注入节点功率作为等式约束条件来提高估计精度,然后对非线性估计的结果和PMU的支路电流相量进行线性估计。模拟了当系统某节点负荷持续变化时,利用等效导纳法对非线性区域节点状态量进行估计,最后采用IEEE 14和57节点系统算例对提出的模型进行了验证。     

The novel usage of spectroscopic ellipsometry for the development of amorphous Si solar cells

We present the novel use of spectroscopic ellipsometry (SE) for the development of a-Si:H solar cell. SE is a very fast and useful tool to measure various optical properties of thin film. In the case of a-Si:H thin film analysis, generally, SE is used to estimate the film thickness, roughness, void fraction, optical constants such as (n,k), and so forth. In this study, optical parameters from SE measurements were analyzed with relation to structural and electrical properties of a-Si:H thin film for solar cell. By analyzing IR absorption spectra and conductivity measurements, it was affirmed that <ε₂> and parameter A by Tauc-Lorentz model fitting of SE data are representative parameters qualifying a-Si:H thin film, and that they have close relationships with FF and light induced degradation property of solar cells. Based on the analysis, solar cells that have i-layers with various E_g were optimized. By this research, easier and faster methodology to develop a-Si:H thin film for thin film Si solar cells using SE measurements was established.     

Electromagnetic interference shielding,mechanical properties and water absorption of copper/bamboo fabric (Cu/BF) composites

Copper/bamboo fabric (Cu/BF) composites were prepared by electroless deposition via a tin-free process. The process involved 3-aminopropyltrimethoxysilane modification, noble metal (Au or Pd) activation and electroless copper planting of BF. The copper deposition rate via Pd catalytic process was 1.01 mg/cm² h, higher than that by Au catalytic process (0.85 mg/cm² h). The microstructure of Cu/BF composites was analyzed by scanning electron microscopy (SEM), and the copper coatings were composed of ball-shaped copper particles. The composition and chemical state of copper layers were measured by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) spectra, Cu⁰ was detected but copper dioxide was not found in both spectra. The electromagnetic interference, water absorption, mechanical tension, conductivity and adhesion properties of Cu/BF samples (weight ratio of Cu/BF: 0.36 ± 0.01) were measured to obtain the qualities of the composites.     

包边质量控制产品条件

在前期SE分析中,通过对包边产品设计提出工艺性要求,包含车门包边形式要求、造型要求、包边工艺性要求、包边结构要求、包边断面尺寸要求等方面,能够有效地预防包边质量缺陷,为后期车身精度控制奠定基础。     

The Impact of an Agile Methodology on the Well Being of Development Teams

This paper describes an empirical study, which addresses the aspect of well being amongst members of the software development teams. The question of interest is whether an agile methodology has any distinct effect on the well being of the software developers. Both quantitative and qualitative methods were utilised, including the participative observation, focus group interviews, close-ended questionnaires and simple statistical tests such as Spearman Correlation and Mann–Whitney test. Initial results showed that an agile methodology (XP) has a positive effect on the level of enthusiasm of the software developers in the most dynamic project. To understand why XP can increase enthusiasm, results are interpreted with references to cognitive, affective and managerial properties of the practices studied. This result needs further investigation on the individual effects of each practice on the wellbeing and attitudes of Software Engineering (SE) teams.     

超高频单片集成锁相环SE564及其应用

详细介绍了锁相鉴频电路的工作原理，并以超高频单片集成锁相环SE564为例，介绍了其结构、组成与应用，具有较强的实用性。     

瑞利衰落信道下的自适应编码调制技术

自适应编码调制技术(adaptive coded modulation,ACM)是一种适用于卫星等无线信道的传输技术,它建立在信道估计的基础之上,通过反向信道将信道状态信息(channel state information,CSI)传送给发送端,使其根据不同的信噪比自适应地改变编码方式和调制方式,从而在不降低误码率(bit error rate,BRE)的条件下,提高信道的频谱利用率(spectral efficiency,SE);介绍了自适应编码调制技术的基本理论;给出了信道估计的方法;分析了其SE性能,仿真了一个基于格码调制(trellis coded modulation,TCM)的ACM系统。     

西门子变频器在1250纵剪上的应用

本文主要介绍了1250纵剪的设备组成和电控系统，采用现场总线技术、6SE70变频器矢量控制、公共直流母线等技术提高了整个机组的装机性能和自动化水平。     

基于Protel99SE的PCB在线修改及若干技巧

采用Protel99SE绘制印刷电路板(PCB)时经常遇到的问题及相应的解决办法。特别提出了在PCB板已经基本定型后,原理图需要进一步修改而引起的PCB在线修改的方法。