Broken-Link Reports from SFX Users: How Publishers,Vendors and Libraries Can Do Better

Abstract

This study analyzes more than 400 SFX broken-link reports sent by users of an academic library. It raises technical issues regarding OpenURL linking in the handling of special journal volume and issue numbers, journal supplemental issues, embargo release dates, book reviews, DOIs, and other areas. It reports on full-text resources with the most broken links, causes of broken links, and the library's responses to users. It also explores how journal publishers, database vendors, and OpenURL vendors can improve the quality of their products and how librarians can better serve users.     

调速用旋变编码器误差分析与校正

旋变编码器受误差因素影响,会在转速位置测量时引入周期性波动,不利于运动控制。对此提出了基于电压矢 量和转速的误差校正方法,采用电压矢量计算直流偏置和幅值偏差并对其进行校正;采用转速谐波幅值计算相位偏差并 对其进行校正。实验结果表明转速位置波动得到了很好的抑制。该方法能有效校正旋变编码器误差。     

基于旋转变压器及TMS320F28035的伺服系统位置检测

为检测伺服系统位置信息,以旋转变压器作为位置传感器,设计了基于芯片AU6802N1的位置检测电路并在此基础上提出了一种仅利用TMS320F28035对旋转变压器转子位置直接解算的方法。该方法综合运用正弦峰值采样、CLA浮点数计算、误差校正等手段。实验表明,该方法在位置解算的速度和精度上可与AU6802N1芯片相比,节约了系统成本,具有一定的实用性。     

E-journal Management: An Online Survey Evaluation

Abstract

Providing access to a wealth of information is a fundamental role of the library. The proliferation of e-journals and aggregate databases has altered the nature of serials collections and the responsibilities of the librarian. To develop a complete perception of current e-journal management, the authors created a survey for small to medium-sized libraries. The survey notes the lack of a unified approach and suggests the need for standards in this area.