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介绍BT-99型水质分析仪在使用过程中经常出现的故障,分析了故障产生的可能原因,并提出了故障排除方法。 相似文献
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介绍谷物水分测定仪显示故障、调零故障、调不到满刻度及示值不准确故障产生的原因,以及检查步骤和故障排除方法。 相似文献
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介绍气相色谱-质谱联用仪的常见故障:与质谱仪调谐相关的故障、与校准和灵敏度相关的故障及与色谱图和质谱图相关的故障,给出了产生故障的可能原因,提出了故障排除的方法。 相似文献
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介绍VITALAB21型半自动生化分析仪常见故障、故障原因及故障排除方法。 相似文献
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杨世柏 《分析测试技术与仪器》1994,(3):35-40
本文将“故障要因图”法应用于电镜真空系统的维修中,作出了H-800型透射电镜真空系统的故障要因图,并依据这一要因图对H-800型电镜真空系统的实际故障进行分析,比较准确地判定了故障部位,指出利用故障要因图分析和查找电镜真空系统故障的部位和原因能取得好的效果。 相似文献
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The HNMR. spectra of phenalene, phenalenone, of some protonated and alkylated derivatives and the spectra of some substituted phenafulvenes are discussed and very qualitatively correlated with the π-electron distribution in some of these systems. 相似文献
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More than one century ago, Lippmann found that capillary forces can be effectively controlled by external electrostatic forces. As a simple example, by applying a voltage between a conducting liquid droplet and the surface it is sitting on we are able to adjust the wetting angle of the drop. Since Lippmann's findings, electrocapillary phenomena – or electrowetting – have developed into a series of tools for manipulating microdroplets on solid surfaces, or small amounts of liquids in capillaries for microfluidic applications. In this article, we briefly review some recent progress of fundamental understanding of electrowetting and address some still unsolved issues. Specifically, we focus on static and dynamic electrowetting. In static electrowetting, we discuss some basic phenomena found in DC and AC electrowetting, and some theories about the origin of contact angle saturation. In dynamic electrowetting, we introduce some studies about this rather recent area. At last, we address some other capillary phenomena governed by electrostatics and we give an outlook that might stimulate further investigations on electrowetting. 相似文献
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This review addresses recent advances in the field of glassy carbon electrodes film‐modified by acidic functionalities. Attention was posed at the architecture of the functionalizing surface film and at practical applications of the relevant sensors. To facilitate the reading, some summarizing tables were included, each one regarding a certain type of surface modification. A final section is aimed at detailing some remarks emerging from the analysis of the reviewed matter. This allowed highlighting the potentialities of the examined sensors, and evidencing some criticisms about how some of their performances were presented in the relevant papers. 相似文献
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WEI Qing-Li GAO Jun HE Fu-Jin ZHANG Shu-Sheng 《结构化学》2007,26(10):1232-1238
The quantitative structure-activity relationship (QSAR) of 16 pyrazole compounds was studied by ab initio method at the HF/3-21G level using Guassian03 soft. The optimized structures together with some characteristic and electric parameters of the title compounds were obtained; some stereo-parameters were calculated by HyperChem software. Stepwise multiple regression method was adopted to establish bi-and tri-parametric models between biological activity and some parameters. The lager ΔE and logP,the higher biological activity; and the biological activity would be promoted with the smaller μ,QN and QPYRA. It provided a theory direction to synthesize some compounds with high activity. 相似文献
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The behaviour of Mo and some other elements on Ag MP-1 in alkaline medium was investigated. Equilibrium distribution coefficients, Kd, are presented for Mo on the anion exchangers AG 1-X2, AG 1-X4, AG 1-X8 and AG MP-1, and for some elements on AG MP-1 in alkaline medium. An anion exchange chromatographic separation of Mo from some of these elements is described and some results obtained with this method are reported. 相似文献
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Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction
Laurent Gavara Thomas Boisse Jean-Pierre Hénichart Adam Daïch Philippe Gautret 《Tetrahedron》2010,66(38):7544-5571
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments. 相似文献
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等离子体引发聚合的机理初探 总被引:5,自引:0,他引:5
等离子体引发聚合与常规自由基聚合存在许多不同之处。本文从等离子体引发聚合物一些现象,如较强的溶剂效应、极高的单体选择性、主成超高分子量聚合物等方面,系统介绍了等离子体引发聚合的机理研究成果,并提出了自己的看法。 相似文献
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近年来,基于三维图像的人脸识别技术已经取得了很大进展,在约束环境下也能获得很好的识别性能,但仍受限于姿态、表情等因素,需要从算法上改进才能解决其影响。本文分别从基于空域直接匹配、基于局部特征匹配和基于整体特征匹配3个角度出发,对人脸匹配算法以及融合算法进行了研究,列出了部分改进算法的实验结果,并分析了算法有效性的原因,总结了目前面临的三维人脸识别算法难以突破的一些困难及未来的研究趋势。 相似文献