A NOVEL STRUCTURE OF ALL-OPTICAL TYPE SILICON MICRORESONATOR

ＩＮＴＲＯＤＵＣＴＩＯＮＩｔｉｓｋｎｏｗｎｔｈａｔｔｈｅａｐｐｌｉｃａｔｉｏｎｏｆａｎＡｌｌ Ｏｐ ｔｉｃａｌｔｙｐｅＳｉｌｉｃｏｎＭｉｃｒｏＲｅｓｏｎａｔｏｒ (ＡＯＳＭＲ)ｏｒｓｅｎｓｏｒｉｓｇｒｅａｔｌｙｒｅｓｔｒｉｃｔｅｄｂｙｔｈｅｐｒｏｂｌｅｍｏｆｏｐ ｔｉｃａｌｃｏｕｐｌｉｎｇ (Ｇｕｃｋｅｌｅｔａｌ.,1 993;Ｐｉｔｃｈｅｒｅｔａｌ.,1 990 ) .Ｔｈｅｖｉｂｒａｔｏｒｓｕｒｆａｃｅｉｓｕｓｅｄｆｏｒｏｐｔｉ ｃａｌｅｘｃｉｔａｔｉｏｎａｎｄｖｉｂｒａｔｉｏｎｐｉｃｋｕｐｉｎａｎｕｍｂｅｒｏｆＡＯＳ…     

Heaviest yet LBO monocrystal grown at CAS

After three years of hard work, a research team led by Prof. HU Zhanggui with the CAS Technical Institute of Physics and Chemistry has made breakthrough progress in the studies of lithium triborate （LBO）, a nonlinear optical crystal.     

针灸推拿综合治疗腰椎间盘突出症

文章分析了腰椎间盘突出症的病因病理,根据中医辩证,应用针灸、推拿、拔罐、牵引加中药外敷等综合治疗获得了满意的效果。     

复杂晶体的化学键和非线性光学效应

系统地提出了复杂晶体化学键的介电理论方法,计算了一些非线性晶体的二阶极化系数d_ij。计算结果和实验值符合很好,同时表明这种方法不仅可应用于复杂晶体,还提供了材料设计的某些依据。     

根据螺旋理论推断有机化合物的绝对构型

运用笔者所提出的螺旋理论,通过钠光D线的旋光性,推断光学活性化合物的绝对构型     

The TREC-5 Confusion Track: Comparing Retrieval Methods for Scanned Text

A known-item search is a particular information retrieval task in which the system is asked to find a single target document in a large document set. The TREC-5 confusion track used a set of 49 known-item tasks to study the impact of data corruption on retrieval system performance. Two corrupted versions of a 55,600 document corpus whose true content was known were created by applying OCR techniques to page images. The first version of the corpus used the page images as scanned, resulting in an estimated character error rate of approximately 5%. The second version used page images that had been down-sampled, resulting in an estimated character error rate of approximately 20%. The true text and each of the corrupted versions were then searched using the same set of 49 questions. In general, retrieval methods that attempted a probabilistic reconstruction of the original clean text fared better than methods that simply accepted corrupted versions of the query text.     

Information Retrieval can Cope with Many Errors

The retrieval of documents that originate from digitized and OCR-converted paper documents is an important task for modern retrieval systems. The problems that OCR errors cause for the retrieval process have been subject to research for several years now. We approach the problem from a theoretical point of view and model OCR conversion as a random experiment. Our theoretical results, which are supported by experiments, show clearly that information retrieval can cope even with many errors. It is, however, important that the documents are not too short and that recognition errors are distributed appropriately among words and documents. These results disclose that an expensive manual or automatic post-processing of OCR-converted documents usually does not make sense, but that scanning and OCR must be performed in an appropriate way and with care.     

复杂晶体的化学键和非线性光学效应

系统地提出了复杂晶体化学键的介电理论方法 ,计算了一些非线性晶体的二阶极化系数dij.计算结果和实验值符合很好 ,同时表明这种方法不仅可应用于复杂晶体 ,还提供了材料设计的某些依据 .     

基于标量衍射理论的图像解密三维信息构造方法

提出合理设置相位延迟以提高光学三维信息解密质量的方法. 利用多个垂直于同一光轴的二维函数,分别以离轴和同轴的形式构造简单三维信息. 采取基于相位抽取的光学三维信息加密算法进行模拟,验证了同轴构造三维信息解密质量受噪声干扰较大,且噪声的产生与加密过程中的相位抽取无关. 通过考察信息相位分布和相位延迟对解密质量的影响,证明合理设置相位延迟可降低解密噪声. 设计2种相位延迟设置方案,分析相应的约束条件.     

宽带综合业务数字网B-ISDN

数字化、网络化、信息化,一场新的信息技术革命铸造一个综合各种信息业务的大容量、易交换、高稳定、智能化的高速数据多媒体通信网--宽带综合业务数字网B-ISDN.