共查询到17条相似文献,搜索用时 218 毫秒
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沸石分子筛修饰的QCM类神经毒气传感器 总被引:1,自引:3,他引:1
研究了Cu2 -Beta型纳米分子筛对类神经毒剂DMMP有机气体的敏感特性,并结合高灵敏的石英谐振微天平(QCM)研制了DMMP气体的传感器.研究结果表明,选择Cu2 -Beta纳米分子筛作为敏感膜对DMMP气体的检测灵敏度大大提高,达到14.481 1 Hz/lg(C/ppm).在0.2 ppm DMMP气体浓度下,传感器的响应时间和恢复时间分别为40 s和100 s,响应达到103Hz.同时经过高温和水汽吹扫脱附处理,该传感器表现了较好的重复性. 相似文献
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采用微扰理论分析了覆盖聚合物敏感膜的水平剪切型声表面波气体传感器(SH-SAW)的响应机理。以针对有机磷毒剂具有良好选择性的含氟多羟基聚硅氧烷(FPOL)膜材料为例,分析了聚合物膜厚以及传感器工作频率在敏感膜吸附气体时对传感器响应的影响。计算结果表明,SH-SAW气体传感器对于不同浓度的甲基磷酸二甲酯(DMMP)气体响应随FPOL膜厚和传感器工作频率的改变呈现非线性变化。为了获得线性特性的传感器响应及较小的声波衰减,在一定的DMMP气体浓度检测范围内,通过理论计算提取出了优化的FPOL敏感膜膜厚和传感器工作频率等参数。 相似文献
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向列型液晶分子具有取向序而无位置序,外界物理、化学和生物刺激非常容易引起分子取向变化,进而导致偏光图像的变化。本文利用玻璃基底表面沉积的Cu2+使4-腈基-4'-戊基联苯液晶(5CB)分子获得沿面垂直取向。当有机磷存在时,有机磷与5CB竞争Cu2+结合位点,从而使5CB分子被有机磷置换而呈水平或倾斜取向。这一取向的变化在偏光条件下通过肉眼即可观察到。利用该原理制作的液晶化学传感器能检测10 ppb的二异丙基磷酸甲基酯(DIMP),响应时间仅25 s。传感器对水蒸汽、乙醇以及丙酮均不响应,具有很高的特异性。与传统方法相比,该方法具有快速、灵敏、制作简单以及不需要复杂装置等优点。 相似文献
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聚甲基[3-(2-羟基-5-氟)苯基]丙基硅氧烷的合成及其应用 总被引:1,自引:0,他引:1
以对氟苯酚和3-溴丙烯为原料,无水乙醇为溶剂,经O-烷化、克莱森重排和硅氢加成得到了有机磷毒剂敏感材料聚甲基[3-(2-羟基-5-氟)苯基]丙基硅氧烷.研究了各因素对各步反应的影响,得到的较佳工艺条件为将对氟苯酚和溴丙烯于55℃回流4 h得到中间产物对氟烯丙基苯基醚(Ⅰ),接着将Ⅰ在200℃ 保温7 h得到2-烯丙基_4-氟苯酚(Ⅱ),然后将Ⅱ和含氢硅油在100℃反应4 h.利用FT-IR和1HNMR对各级反应产物结构进行了表征.将聚甲基[3-(2-羟基-5-氟)苯基]丙基硅氧烷料涂覆在QCM传感器上研究了其对有机磷毒剂模拟剂DMMP的响应特性.结果表明传感器响应迅速,对干扰气体、水和乙醇的响应低于含有苯酚官能团的聚合材料. 相似文献
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为了改善石墨烯室温气体传感器响应低、恢复性差等缺点,本文设计了一种石墨烯基气体传感器,其具有石墨烯叉指电极以及中央铜薄层沉积区结构。通过XPS分析发现,由于存在不同程度的自然氧化,铜薄层存在Cu0、Cu+、Cuδ+及Cu2+四种价态成分;且随着沉积厚度的变化,四种价态成分所占比例也发生变化。实验发现铜薄层沉积厚度为8nm对应的器件性能最佳,对5×10-6和0.3×10-6 NO2的室温响应分别为-30.9%和-8.1%,对105×10-6和10×10-6 NH3的响应分别为+29.1%和+5.9%,且具有较好的恢复性能。本文基于密度泛函理论计算了本征石墨烯、修饰有铜及铜氧化物的石墨烯表面对NO2和NH3吸附的微观参量,并讨论了器件的响应机制。 相似文献
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基于13X型沸石分子筛的类神经毒气传感器 总被引:1,自引:0,他引:1
研制了基于13X型分子筛阻抗型气体传感器,探测了神经类毒气沙林的相似物甲基磷酸二甲脂(DMMP)。通过交流电压对传感器进行激励,得到其交流阻抗谱的变化,从而实现对不同体积分数DMMP的检测。对0.2×10-6,0.4×10-6和1×10-6DMMP气体分别进行了检测,在1×10-6时(频率为0.01 Hz)电阻的相对变化可达13.2%;同时,分别采用13X型和Cu-β型分子筛作为敏感膜对1×10-6DMMP,100×10-6CO2和饱和蒸汽压下的乙醇气体进行了选择性比较实验。实验表明:基于13X型分子筛膜传感器对DMMP的探测有较好的灵敏度和选择性。 相似文献
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采用丝网印刷技术制备了以In2O3为敏感电极的锆基安培型三电极NO传感器用以探测10-9级NO气体。用X射线衍射仪(XRD)和扫描电镜(SEM)对该传感器进行了理化分析;通过测量其在不同温度和不同NO浓度的气氛中的伏安特性曲线和时间响应曲线,研究了传感器的电流输出信号和NO浓度的关系以及时间响应特性。实验表明:在350℃~500℃测试温度范围内,极化电压为-60 mV,NO浓度变化为0~900×10-9时传感器响应电流的变化值Δcurrent和NO浓度之间存在较好的线性关系并且传感器在400℃时响应值最大。在被测气体总流量为100 cm3/min时,传感器信号90%的响应和恢复时间分别为18 s和12 s。传感器信号不受CO2浓度变化的影响,传感器的响应信号在测试时间里具有较好短期稳定性,但长期稳定性有待进一步提高。本文还采用阻抗谱分析方法对传感器的响应机理进行了初步的探索。 相似文献
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Heidi J. VanTreeckAuthor VitaeDarrin R. MostAuthor Vitae Bart A. GrinwaldAuthor VitaeKurt A. KupchoAuthor Vitae Avijit SenAuthor VitaeMichael D. BondsAuthor Vitae Bharat R. AcharyaAuthor Vitae 《Sensors and actuators. B, Chemical》2011,158(1):104-110
The performance characteristics of liquid crystal (LC)-based sensors for detection of dimethylmethylphosphonate (DMMP), a representative organophosphonate compound and simulant of chemical warfare agent sarin, are presented. The equilibration coordination interaction among the aluminum ions on a surface, the cyano group in LCs, and the phosphoryl group in DMMP have been exploited to achieve sensitive, fast, and reversible sensor responses. Measurement of the response time of the sensor allows quantitative detection of an unknown concentration of DMMP with high accuracy. The strong coordination interaction between the cyano group present in the LC and the aluminum ions supporting the film of LC provides immunity to exposure to a number of potentially interfering compounds including high humidity. Exposure studies under varied temperature and humid conditions show a minimal effect on the sensor performance. Although the sensors stored at room temperature exhibited slightly diminished sensitivity, the sensors stored at 4 °C remained functionally stable for at least six months. These results combined with the ease of fabrication using the established processes, low cost associated with off-the-shelf components, and small foot print suggest that these LC-based sensors can form the basis of a new class of low cost, light weight, robust sensors for a number of detection applications. 相似文献
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Meng Zhang Xu Chen Yuan Mei Xudong Zhang 《International journal of remote sensing》2019,40(18):7017-7032
Understanding the mechanism of different imaging characteristics is necessary for image interpretation and information extraction of internal solitary waves (ISWs). In this article, the experimental method is used to reveal the mechanism of different bright and dark patterns in optical remote-sensing images. It provides a scientific method to interpret the imaging characteristics of ISWs in optical remote-sensing images. The results prove that there are two critical angles which are important for optical remote-sensing image interpretation. The critical angle is related to the zenith angle of the light source, sensor, and the wave slope modulated by ISWs. When the zenith angle of the light source is fixed and the zenith angle of the sensor is located between two critical angles, the ISWs appear as dark–bright pattern in optical remote-sensing images. Otherwise, the ISWs appear as bright–dark pattern. This method has been applied to the images acquired around the Dongsha Islands in the South China Sea, and similar results are obtained which indicate that the method is effective and applicable. 相似文献
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为降低FAIMS传感器制作的复杂度与成本,设计了一种基于PTFE基板的FAIMS传感器.该传感器由漂移管、离子源及外围电路组成.其中漂移管基于PTFE基板构建,使用PCB工艺制备Au电极,利用厚度为0.4 mm氧化铝条作为绝缘支撑片将上下电极隔离并形成通道,用于离子分离与检测,漂移管的总体积1.9 cm3.离子源通过针-网式电晕放电建立,通过软焊接工艺连接到FAIMS上基板.外围电路包括FAIMS工作所需的高频高压非对称电场及补偿电场产生电路和微弱离子电流放大电路.常温下,传感器响应恢复时间小于3 s.利用化学战剂模拟剂甲基膦酸二甲酯DMMP(Dimethyl Methylphosphonate)测试了传感器的灵敏度,实现了0.5 μg/m3的量级DMMP样品的检测. 相似文献
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介绍了一种新型柔性电容式湿度传感器.该柔性电容式湿度传感器采用液晶高分子聚合物(LCP)作为衬底,金属铜(Cu)作为叉指电极,聚酰亚胺(PI)作为湿度传感器的湿敏介质.LCP衬底的应用使得该传感器具有良好的柔性和可弯曲性.该柔性湿度传感器与传统硅基湿度传感器相比较具有成本低廉、结构简单、制作方便等优点.该柔性湿度传感器在25℃下的平均灵敏度为0.04%pF/%RH,最大回滞为±4.16%RH,其平均灵敏度在25℃~70℃范围内受温度影响较小.在25℃下其响应时间和恢复时间分别为36 s和39 s.该柔性湿度传感器可以应用于环境湿度检测、人工电子皮肤系统和可穿戴设备等领域. 相似文献
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Atsushi Yoshizawa 《Journal of the Society for Information Display》2008,16(12):1189-1194
Abstract— The molecular design of a liquid crystal to stabilize a blue phase III (BPIII) is reviewed, and the electro‐optical switching with a response time on the order of 10?2 sec for BPIII exhibited by a novel chiral liquid crystal is reported. Binaphthyl derivatives and T‐shaped compounds are presented, and the structure‐property correlations of the chiral compounds are discussed. Two origins of the twisting power of the compounds, i.e., their inherent molecular chirality and the chirality‐induced twist conformation, play an important role in the appearance of the BPIII. Furthermore, BPIII was also induced in some binary mixtures of a host nematic liquid‐crystal possessing molecular biaxiality and a conventional chiral compound. The electro‐optical switching in the BPIII is attributed to an electric‐field‐induced phase transition between the BPIII and nematic (N) phases. BPIII is on the microscopically twisted nematic order, but is macroscopically isotropic. Therefore, the present technology can offer a pronounced black state in the BPIII without surface treatment and a homogeneous bright state in the induced N phase. 相似文献