用PowerPiont 2000制作电子教案

针对当前教学体制改革,用实例阐述了如何用PowerPiont2000制作电子教案,在教学过程中充分利用计算机、大屏幕投影设备等先进的教学设施,改变教学模式,提高学生的学习兴趣,提高教学效率。     

Extendible elements of the alternating groups

An element σ of A_n, the Alternating group of degree n, is extendible in S_n, the Symmetric group of degree n, if there exists a subgroup H of S_n but not A_n whose intersection with A_n is the cyclic group generated by σ. A simple number-theoretic criterion, in terms of the cycle-decomposition, for an element of A_n to be extendible in S_n is given here.     

Gold nanoparticle-enhanced surface plasmon resonance measurement with a highly sensitive quantification for human tissue inhibitor of metalloproteinases-2

Two different methods for the quantification of human tissue inhibitor of metalloproteinases-2 (TIMP-2) were developed using surface plasmon resonance (SPR) and gold nanoparticles for signal enhancement. The first method, a competitive assay, used TIMP-2 immobilized to the sensor surface and the inactive form of matrix metalloproteinase-2 (proMMP-2) (EC 3.4.24.24) adsorbed to gold nanoparticles. The sensor signals resulting from the interaction of MMP-2-gold nanoparticles with immobilized TIMP-2 were inversely proportional to the amounts of TIMP-2 of the sample. The measuring range for TIMP-2 was about 15–180 pM. The second method, a one-step sandwich assay, used proMMP-2 immobilized to the sensor surface and an anti-TIMP-2 monoclonal antibody coupled to gold nanoparticles. The lower detection limit of this assay format was 0.5 pM of TIMP-2. The binding signals were highly reproducible up to 100 pM of the inhibitor. The improvements obtained in TIMP-2 quantification over already existing tests could contribute to a better understanding and diagnosis of diseases like cancer.     

Activation of trisacryl gels with chloroformates and their use for affinity chromatography and protein immobilization

In this study we describe the activation with chloroformates of Trisacryl-GF-2000, a new synthetic gel support that is stable, hydrophilic, and contains large amounts of hydroxyl groups available for activation. Of all the reagents tested, the activation withN-hydroxysuccinimide-chloroformate andp-nitrophenylchloroformate in organic solvents provides the best activation yield and subsequent coupling. When Trisacryl was activated in acetone with the chloroformates in the presence of 4-dimethylaminopyridine as base and catalyst, up to 30% of the hydroxyl groups, (i.e., 1/repeating unit) could be activated. Amino-containing ligands and proteins could be coupled to these carriers at pH 8 or higher. For better results in affinitychromatographic applications, spacers of ε-amino caproic acid or diaminohexane were introduced. The efficacy of these columns was demonstrated by purification of enzymes, antibodies, and antigens. The performance of these new columns were compared with that of Sepharose columns activated in various ways. In every case, the properties of the Trisacryl support proved superior with particular reference to the purity of the product obtained.     

The vibrational analysis of methylarsonic acid,trideuteromethylarsonic acid and their anions

Raman and IR spectra of methylarsonic acid, CH₃AsO₃H₂, trideuteromethylarsonic acid, CD₃AsO₃H₂ and their anions in aqueous solution and the solid state are discussed. Some results of a general valence force field and a Urey-Bradley force field are reported.     

Using a process-centered approach to minimize the effort of compliance

 The complexity of different quality standards can, in principle, be covered by different approaches and strategies. In-depth process mapping of quality control (QC) work streams was used by the analytical laboratories of Lonza AG to show up the principle differences in being compliant to different quality systems. The results identified two main drivers for all necessary actions: process-related activities and infrastructure-related activities. In addition, a clear indication of the economic impact of these driving forces was gained, which led the laboratories to decide on a process-oriented approach. This approach has the advantage of being able to reflect the different demands of different quality assurance (QA) regulations within the same QC organizational structure. Following the process helps avoid unnecessary efforts in analytical work and represents a very economical approach, at the same time, providing high flexibility to react to different QA or customer demands. Received: 5 July 2002 Accepted: 12 November 2002 Acknowledgements The process-oriented approach resulted from many, very challenging discussions for which I would like to thank the staff of my organization (Analytics & QC), especially, the QA staff and the LIMS team. Presented at Analytica Conference, 23–26 April 2002, Munich, Germany Correspondence to B. Ciommer     

一种基于DSP的JPEG2000视频压缩系统的实现

JPEG2000是国际标准化组织ISO和国际电信联盟ITU T共同制定的新一代图像压缩标准.它是基于EB COT算法,使用DWT,采用两层编码策略, 能够获得较好的压缩率.介绍了JPEG2000的基本特点,概述了其图像编码系统.详细描述基于DSP的JPEG2000硬件压缩系统各个硬件的选择以及具体的实现过程.     

cdma2000 1x EV-DO前向链路高速分组数据传输中的调度算法

在保证用户间公平性的前提下,为尽量提高cdma2000的增强型1xEV DO系统前向链路的数据吞吐量,通过讨论现有的多种调度算法原理,分析了影响系统吞吐量和公平性的因素,在此基础上提出将用户平均请求传输速率、限制用户最小平均传输速率和系统最小吞吐量的影响同时引入调度算法的思想,通过在CadenceSPW软件平台上的仿真研究表明,改进后的调度算法在保持公平性的前提下,有效提高了系统前向链路吞吐量.     

平板显示器件的多种灰度显示方案

介绍了各种灰度实现的方案，分析其灰度级实现原理和各自的特点，并着重描述子场和PWM方法；同时介绍一款专用灰度调制芯片BHL2000及其在动态图像显示中的实际应用方案，该芯片已在目前国内最大的FED驱动电路中采用。较其它FPD灰度调制方面的文章，本文的分析更为全面，并举出应用实例。     

解决图像监控系统中图像传输质量的关键

在图像监控系统中，图像的传输是一个关键问题．图像在传输过程中容易出现延时、抖动、失真等现象．在较全面地分析图像传输中的压缩标准、传输协议、传输方式，以及传输软件设计等一些关键技术的基础上，提出了提高图像传输质量的有效方法．