A disposable sensor based on immobilization of acetylcholinesterase to multiwall carbon nanotube modified screen-printed electrode for determination of carbaryl

A simple method has been devised for immobilization of acetylcholinesterase (AChE) covalent bonding to a multiwall carbon nanotube (MWNT)-cross-linked cellulose acetate composite on a screen-printed carbon electrode (SPCE) and a sensitive and disposable amperometric sensor for rapid determination of carbaryl pesticide is proposed. The immobilized enzyme was preserved on this film because of the excellent biocompatibility and non-toxicity of cellulose acetate. Based on the inherent conductive properties of the MWNT, the immobilized AChE had greater affinity for ATCl and excellent catalytic effect in the hydrolysis of ATCl. MWNT improved the interface enzymatic hydrolysis reaction and increased the amperometric response of the sensor. Under optimum conditions, the inhibition of carbaryl on AChE increased linearly with the increasing concentration of carbaryl in two ranges, from 0.01 to 0.5 μg mL⁻¹ and from 2 to 20 μg mL⁻¹, with the correlation coefficients of 0.9985 and 0.9977, respectively. The detection limit was 0.004 μg mL⁻¹ taken as the concentration equivalent to 10% decrease in signal. The sensor showed acceptable stability, accuracy and could be fabricated in batches, thus it is economic and portable. This type of disposable enzyme-based amperometric sensor has extensive application potential in environmental monitoring of pesticides.     

发展3G时不我待--兼析民族3G标准的发展

当今通信业最热门的话题非3G莫属。尽管2000年3G许可证的拍卖引发了欧洲乃至全球电信经济的萧条,但中国实行的“积极试验,谨慎决策”的政策,确保了电信业的快速增长。如2001年和2002年中国的电信业务收入分别增长了16.1%和14.4%,继续高于GDP的增长速度。今天,3G在国际市场上正步入良性发展轨道,中国移动通信市场也在向纵深发展,包括促进有效竞争、支持民族3G标准TD-SCDMA的发展和应用等。一、中国发展3G迫在眉睫1.用户需要3G中国市场对移动话音、移动新业务和新应用的需求潜力十分巨大。2002年底,中国移动通信的用户数(中国移动+中国…     

GIS数据库中的数据挖掘

首先探讨了DM在GIS中应用的必要性和可能性,然后讨论了GIS数据库中的DM可以发现的知识类型、可以使用的方法,可以采用的DM系统原型,最后简单介绍了DM对GIS的贡献。     

油气吸收回收系统的研究及工业应用——(Ⅱ)工业试验及效果分析

在油气吸收回收系统中型试验的基础上，开发了常温常压吸收法工业化油气回收系统，并进行了工业应用。结果表明，该油气回收系统平均回收率可达95．13％，每年可回收汽油529t；装车期间装车口周围环境大气中总烃浓度平均降低98．06％。企业通过实施油气回收系统，节能及经济效益明显，且很好地改善了装车场所的作业环境，克服了油气排放带来的安全隐患。     

维氏硬度检测中不确定度初探

通过分析维氏硬度检测中的不确定度，计算了各不确定度分量所占的权重，得到HVlO(440--738)范围内的相对不确定度为1．3％--1．7％。     

Microphase structure and calculations of the interphase in poly (styrene-b-methylphenylsiloxane) diblock copolymers: a comparative study from small-angle X-ray scattering,electron spectroscopic imaging and solid-state nuclear magnetic resonance

The microphase structure of a series of poly (styrene-b-methylphenylsiloxane) (PS-b-PMPS)-diblock copolymers with various compositions and molecular weights has been studied by small-angle X-ray scattering, electron spectroscopic imaging and solid-state nuclear magnetic resonance spectroscopy. This diblock copolymer system is miscible within a distinct range of temperature and molecular weight exhibiting an upper critical solution temperature. The three chosen methods which complement each other can be applied to the chemically unmodified model system. The results of the various measurements correlate to describe the microphase structure, the domain size and the interphase.     

单液晶光阀彩色大屏幕投影显示

设计一电路,将彩色图象信息编码到黑白CRT的亮度之中,并将其写入液晶光阀,用白光读出,当编码合适时,读出的象颜色可与原图像一致。本文讨论了这一技术原理并进行了单液晶光阀彩色大屏幕投影的实验验证。     

天然调味料──酵母抽提物的研究进展

着重论述了酵母抽提物的特性、在食品中的应用前景、制造方法、工业化生产中存在的问题及其解决方法，并对酵母抽提物的发展方向作一展望。     

大角度倾转法在碳化物研究中的应用

蠕变过程中碳化物形貌，类型，数量和分布状态的变化直接影响着材料的高温性能，因而在材料的蠕变得到了广泛的重视，介绍了一种在碳膜萃取复型样品上利用Ｈ－８００透射电子显微镜的双倾样品台进行了大角度倾转，来观察碳化物形貌并鉴定其类型的试验方法。