光电子技术-专业英语.pptVIP

第12章 科技文献检索 12.7 文献检索的一般步骤 文献检索工作是一项实践性和经验性很强的工作，对于不同的项目，可能采取不同的检索方法和步骤。检索程序与检索的具体要求有密切关系，大致可分为以下几个步骤： 1. 分析待查项目，明确主题概念 2. 选择检索工具，确定检索策略 4. 查找文献线索，索取原文 3. 确定检索途径和检索标识 第12章 科技文献检索 12.8 文献数据库检索 12.8.1 检索工具的类型 1．布尔检索 常用的布尔逻辑算符有三种，分别是逻辑或“OR”、逻辑与“AND”、逻辑非“NOT”。 下面以“电子科学与技术”和“文献检索”两个词来解释三种逻辑算符的含义： （1）“电子科学与技术”AND“文献检索”，表示查找文献内容中既含有“电子科学与技术”又含有“文献检索”词的文献。 （2）“电子科学与技术”OR“文献检索”，表示查找文献内容中含有“电子科学与技术”或含有“文献检索”以及两词都包含的文献。 （3）“电子科学与技术”NOT“文献检索”，表示查找文献内容中含有“电子科学与技术”而不含有“文献检索”的那部分文献。 Chapter 10 Optical Tweezers 10.5 Application of Optical Tweezers Extensive use of optical trapping techniques has been made in the field of microchemistry, which studies the spectroscopy and chemistry of small um-sized domains. Beam scanning techniques were developed for trapping of um-sized metal particles, low index particles, and moving of particle arrays in complex patterns. These experiments are made by Masuhara et al Chapter 10 Optical Tweezers 10.6 Future of Optical Tweezers It seems fair to predict that use of optical manipulation techniques will continue to grow at an increasingly rapid pace in the many subfields of physics, chemistry, and biology involving small particles. We are entering an era of increasing emphasis on the small for applications and for basic science. The role of laser tweezers and manipulation in basic sciences has been truly revolutionary. The impact of laser technology on the biological sciences may prove to be equally revolutionary. Chapter 11 Photonic Crystal Fiber 11.1 The origins of PCFs Optical fibers are widely used in optical fiber telecommunications, which permits transmission over longer distances and at higher bandwidths (data rates) than other forms of communications. PCF is a new class of optical fiber based on the properties of photonic crystals. 11.1.1 Conventional optical fibers Optical fibers, which rely on total internal reflection1 (TIR) to guide light and transmit information in the form of short optical pulses o