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为提取LED激发海水叶绿素a产生的痕量荧光信号,实现海水叶绿素a原位检测,基于荧光诱导检测原理结合正交同步检波电路,设计了荧光叶绿素a传感器。通过对激发光源的调制,输入电流信号的转换与放大,荧光信号的正交同步解调以及数字混合低通滤波算法实现海水叶绿素a浓度的原位检测。实验证明该海水叶绿素a传感器具有精度高、抗环境光干扰能力强、小型化、功耗低等优点,分辨率可达到0. 01μg/L。 相似文献
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荧光分光光度法是叶绿素a的国家标准检测方法之一,灵敏度高,但需要荧光计,设备相对较贵.针对荧光值的测量,以往的集成电路式荧光计是把荧光强度转化为微弱电信号.本研究提出了一种新的测量方法:根据荧光图像亮度值估算荧光强度.研究中,应用调制紫外激光激发叶绿素a,CCD接收荧光图像,利用小波域多尺度积对图像有效荧光部分进行去噪与边缘检测,确定荧光所在范围与亮度值.经大量定标实验做出数据库,结果表明,荧光图像法能较为准确地计算出藻类浓度,设备便携、简单,可应用在航拍中做大范围海域检测. 相似文献
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基于伪随机序列调制的荧光测量系统 总被引:1,自引:0,他引:1
荧光分析法和伪随机序列技术均在多个领域有广泛应用。荧光测量过程中常伴随着复杂的背景噪声和干扰,为测量精度的提高带来了困难。利用伪随机序列的相关特性和频谱扩展效应,提出了一种适用于荧光测量系统的,基于伪随机序列的激发光调制方法。通过建立数学模型,从信号和噪声的频谱角度定量分析了伪随机序列调制系统对噪声和干扰的抑制能力,给出了序列参数与测量系统信噪比之间的关系。最后将该调制方法应用于一个典型的荧光测量系统(荧光型叶绿素仪)中。理论和实验结果都表明,使用伪随机序列调制方式能显著提高荧光检测信噪比,叶绿素仪的线性响应相关系数R2在0.999以上,达到国外同类型高端仪器水平。 相似文献
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基于表面开孔光纤的集成式亚硝酸盐微流荧光传感器 总被引:1,自引:0,他引:1
利用中空悬挂芯光纤研制了一种将荧光猝灭反应区建立在空心光纤内部的光纤集成荧光在线微流传感器。利用CO2激光器在光纤表面刻蚀微孔,使得试剂可由微孔注入光纤内部并混合形成稳定的微流。在悬挂芯光纤纤芯倏逝场的激发下,指示剂分子产生荧光,所产生的荧光被耦合到纤芯内部并在出射端被检测。文中利用光纤内部的荧光猝灭反应实验确定了亚硝酸盐溶液的浓度。结果显示:微流可在短时间通过光纤,传感器能以较快的速度检测溶液浓度。另外,当亚硝酸盐溶液的浓度为0.1~2.6mmol/L时,荧光猝灭程度与溶液浓度呈较好的线性关系,结果证明了该集成式光纤内微流控传感器方案用于微量荧光检测的可行性。 相似文献
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将一只由线圈与电容元件共同组成的无源线圈放置于探测线圈与待测电解质溶液组成的测量系统中,借助无源线圈与两者之间的电磁感应耦合,可在谐振频率点附近提高测量系统的探测性能。以塑料容器内0~5%质量分数浓度的Na Cl溶液为探测目标,对无源线圈置于目标溶液前侧及背侧两种情况下的阻抗谱进行了实验分析。结果表明,相同探测距离下,介入无源线圈的测量系统对电解质溶液的浓度表现出更高的灵敏度。当目标溶液位于探测线圈敏感距离之外时,介入无源线圈后依然可实现有效的溶液浓度测量。无源线圈的这种增强效应可提升电磁感应系统的有效探测距离,实现电解质溶液或生物组织等低电导率物质的远距离非接触测量。 相似文献
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叶绿素a原位监测在海洋生态系统健康评估与碳循环过程研究中有重要价值。设计了一套原位叶绿素a的精密测量方案,以交流调制检测为基本方法,开发了交流模拟放大通路,使用开关检波系统完成最后的检波。噪声测试实验表明系统电流分辨力达到186.27 fA。通过仿真和对比实验证明了开关检波系统具有很强的频率选择特性,在系统噪声抑制方面起重要作用。标准叶绿素标定实验表明在0~30μg/L内系统线性度良好,用直线拟合R2=0.998 5,检测灵敏度S=0.008 1μg/L,满足使用需求。 相似文献
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微机化的超声液体浓度在线检测仪 总被引:2,自引:0,他引:2
本文介绍了一种超声波液体溶液浓度的在线检测方法,并研制了相应的以单片机和计算机为核心的在线检测仪,计算机中的溶液成份数据库中存贮了多种溶液的声时,温度及浓度关系曲线,检测时可根据存贮的曲线反演出浓度;溶液成份数据库为开放系统,用户可自己添加数据库中没有的关系曲线,从而可检测该溶液浓度;仪器采用了声时、声幅衰减及数字处理技术联合排除气泡干扰方法,增强了仪器的稳定性;仪器采用了主精度测声时方法,以提高浓度测量精度,计算机提供了数据查询及图形处理等功能,极大地方便了用户生产管理。 相似文献
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Yoon Jo Kim Yogendra K. Joshi Andrei G. Fedorov 《Journal of Mechanical Science and Technology》2008,22(2):338-349
Theoretical analysis and simulation of performance of an air-cooled microchannel absorber is reported in this study. It is
shown that the air-cooled microchannel absorber can be integrated into an absorption-based miniature electronics cooling system
by which the chip junction temperature can be maintained near room temperature, while removing 100 W of heat load. Water/LiBr
pair is used as the working fluid and refrigerant vapor is intended to counter-currently flow against aqueous LiBr solution
flow. Parametric study is carried out to determine the effects of several operating parameters, including inlet temperature
and mass flow rate of the coolant, and inlet temperature of LiBr solution. To facilitate the air-cooling of microchannel absorber,
an offset-strip-fin array is adopted, by which enhanced air-side heat transfer coefficient and large heat transfer area are
obtained. The performance of the air-cooled absorber is compared to liquid-cooled absorber. 相似文献
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Panpan Xu Qi Chen Lei Cao Tingting Tu Jianguo Gao 《Tribology - Materials, Surfaces & Interfaces》2017,11(2):83-87
Water can be used as an ecological lubricant base if the water-based additives are properly developed to modify its tribological properties. Additionally, those additives should be friend both to human and nature. Pullulan is a naturally occurring polysaccharide, which is biodegradable and non-toxic and widely used in food and nonfood applications. We focus here on understanding the lubrication properties of pullulan, in aqueous solution in absence and presence of sodium salts. Lubrication is studied using a ball-on-disk tribometer with steel–steel surfaces and the friction coefficient and wear are measured in the boundary lubrication regimes. The adsorption of pullulan molecules onto steel surface is determined by measuring wettability of friction couples. It was found that the addition of pullulan improves the lubricating properties of water. The lubricating performance of Pullulan solution could be further improved if sodium chloride or sodium fluoride is added. The tribological results obtained were correlated with the adsorption capacity of pullulan molecules onto steel surface. 相似文献
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Junsheng Wang Yongxin Song Sun Jinyang Xudong Wu Yeqing Sun Xinxiang Pan Dongqing Li 《Measurement》2013
Sweat test based on chloride ion selective electrode is the common method for the diagnosis of Cystic Fibrosis (CF). In our previous study, the possibility of using chloride ion sensitive fluorescent dye to determine the chloride ion concentration with a small volume of sample has been explored. However, we found the conventional Stern–Volmer Equation is applicable only for large systems such as a fluorescent microscope with a large volume of sample and dye solution; and it is not valid for portable devices using a small photo detector and a small volume of sample and dye solution. Therefore, in this paper, extensive experiments were performed by using a miniature fluorescent detection system; the effects of the parameters including the concentration and the volume of fluorescent dye solution, the coefficient of Stern–Volmer plot, and the volume ratio of the fluorescent dye solution and the chloride solution were studied; and a modified Stern–Volmer Equation was obtained. Using the modified Stern–Volmer correlation, the miniature fluorescent detection device can detect the chloride ion concentration correctly and rapidly. 相似文献