Optimization of a GFAAS method for determination of total inorganic arsenic in drinking water

The new 10 μg l⁻¹ arsenic standard in drinking water has been a spur to the search for reliable routine analytical methods with a limit of detection at the μg l⁻¹ level. These methods also need to be easy to handle due to the routine analyses that are required in drinking water monitoring. Graphite furnace atomic absorption spectrometry (GFAAS) meets these requirements, but the limit of detection is generally too high except for methods using a pre-concentration or separation step. The use of a high-intensity boosted discharge hollow-cathode lamp decreases the baseline noise level and therefore allows a lower limit of detection. The temperature program, chemical matrix modifier and thermal stabilizer additives were optimized for total inorganic arsenic determination with GFAAS, without preliminary treatment. The optimal furnace program was validated with a proprietary software. The limit of detection was 0.26 μg As l⁻¹ for a sample volume of 16 μl corresponding to 4.2 pg As. This attractive technique is rapid as 20 samples can be analysed per hour. This method was validated with arsenic reference solutions. Its applicability was verified with artificial and natural groundwaters. Recoveries from 91 to 105% with relative standard deviation <5% can be easily achieved. The effect of interfering anions and cations commonly found in groundwater was studied. Only phosphates and silicates (respectively at 4 and 20 mg l⁻¹) lead to significant interferences in the determination of total inorganic arsenic at 4 μg l⁻¹.     

Protein family classification and functional annotation

With the accelerated accumulation of genomic sequence data, there is a pressing need to develop computational methods and advanced bioinformatics infrastructure for reliable and large-scale protein annotation and biological knowledge discovery. The Protein Information Resource (PIR) provides an integrated public resource of protein informatics to support genomic and proteomic research. PIR produces the Protein Sequence Database of functionally annotated protein sequences. The annotation problems are addressed by a classification-driven and rule-based method with evidence attribution, coupled with an integrated knowledge base system being developed. The approach allows sensitive identification, consistent and rich annotation, and systematic detection of annotation errors, as well as distinction of experimentally verified and computationally predicted features. The knowledge base consists of two new databases, sequence analysis tools, and graphical interfaces. PIR-NREF, a non-redundant reference database, provides a timely and comprehensive collection of all protein sequences, totaling more than 1,000,000 entries. iProClass, an integrated database of protein family, function, and structure information, provides extensive value-added features for about 830,000 proteins with rich links to over 50 molecular databases. This paper describes our approach to protein functional annotation with case studies and examines common identification errors. It also illustrates that data integration in PIR supports exploration of protein relationships and may reveal protein functional associations beyond sequence homology.     

CAHN－2000磁天平的调试与数据处理系统的研制

叙述了ＣＡＨＮ－２０００磁天平（美国）调试过程中如何解决液氮温区的测试，自制了磁天平与计算机的接口，编写了数据采集、处理和控制等高原 软件，节省了几万美元，部分指标超过原配套水平，三年来仪器在对国同外开放过程中，液氮温区的工作一直正常，实测了上千个样品，提供的数据已撰写数十篇文章在国内外刊物上发表。由此说明，要充分发挥进口仪器的使用效率，必须对仪器的工作原理、结构特点有透乇的了解，同时要有相当的自     

高校师资管理系统设计与关键技术

结合某高校校园信息化建设的实践，介绍了使用PowerBuilder9．0作为前台，SQL Server 2000作为后台，开发一个高校人事管理系统的思路、关键技术及设计过程。     

成绩录入系统确保数据正确性的策略

主要讨论如何在成绩录入系统中确保输入数据的正确性，提出从客户端的数据录入应用程序和数据录入后校验两个方面确保录入数据正确性的策略，并详细介绍了双工输入比较法、过滤按键、数据实时检验及数据录入后进行的即时检查和总结性校验等具体方法。     

基于XML的Web数据交换服务平台的设计与实现

依托Web提出了一种以XML文件作为中间结果实现异构平台数据交换的解决方案，满足了电子政务处理过程中对不同形式数据的处理要求．     

实时数据交换原理及其编程实现

实时数据交换(RTDX)为调试DSP算法提供了一个实时、可视的环境，为实时信号处理算法的精确快速设计提供了很好的解决方案。本文对RTDX的原理进行了分析，从应用角度给出了RTDX的编程实现，用VB6．0进行了主机OLE自动化客户程序设计，用C语言进行了DSP目标应用程序设计。     

微机在非电量测试系统中的应用

本论述了通过开发一套微机辅助测试系统，利用此系统可进行测试数据的自动采集与分析处理，同时简要地介绍了数据采集与处理软件。     

校园网多链路接入Internet的设计与实现

校园网的出口是网络规划和建设中需要重点考虑的问题,它关系到校园网用户对Internet访问的速度,本文就校园网的多链路接入方法进行了分析,并针对CISCO6509路由器给出了解决数据分流,地址转换,访问控制的具体实现.     

分布式数据库数据访问原理及仿真

针对分布式程控交换机内部的关系型数据库，以阿尔卡特的全分散控制交换机为对象，研究了数据访问原理及数据库对各种关系的访问过程。对分布式程控交换机的数据库结构作了深层分析，讨论了数据访问模型，用宏指令编程完成了数据访问仿真系统设计，并给出了仿真模型的确定方法。通过对实关系的访问过程分析，说明了该方法的可行性，并推导出当进行大批量数据访问时，该方法可提高数据修改和查询效率。经在交换机上运行，结果稳定可靠。