基于传感器阵列瞬态响应信号分析的气体识别关键技术研究

气体识别关键技术是对气体进行检测的一种技术手段,通过模拟生物嗅觉功能,能够保证气体检测具有较高的效率性和准确性。气体识别技术在公共安全检测、食品质量控制、环境保护等方面发挥了日益重要的作用,这就促进了该技术手段的不断进化和提升。基于传感器阵列瞬态信号分析的气体识别技术,注重对多个气体传感器之间相互独立的特性进行应用,通过瞬态响应曲线对气体有效特征进行提取,以实现对气体特点的识别。基于传感器阵列瞬态响应信号分析的气体识别,侧重于信号的获取、特征提取、模式识别等内容,从而采取定性分析与定量分析相结合的方法,对气体进行较为准确的识别。     

高灵敏的酞菁铜薄膜NO_2气体传感器

本文采用真空气相物理沉积技术,在平面叉指电极上沉积酞菁铜薄膜制成的气体传感器。该传感器对NO_2有很高的灵敏度和良好的选择性,能检测出空气中1ppm浓度的NO_2,响应时间几十秒、恢复时间几分钟。在320℃下进行退火处理,传感器的稳定性和重复性有明显的改善。     

氧化锌-铅酞菁复合膜对氧化性气体的新的传感特性

本文报告了覆盖在铅酞菁(Lead-Phthalocyanine缩写为PbPc)薄膜上的氧化锌膜电导对二氧化氮和纯氧的新的高灵敏响应,并对可能的气敏机理作了推测。     

基于单根酞菁铜纳米线的FET式H_2S气体传感器

结合FET和一维微纳材料的优势,构筑了具有高灵敏度和低检测极限的FET式H2S气体传感器。研究结果发现,在室温条件下,器件对体积分数5×10–6至50×10–6的H2S具有良好的灵敏度和低检测极限(5×10–6)。相比于薄膜FET传感器,检测极限降至原来的1/20。与PMMA绝缘层比较研究结果显示:引起器件对H2S的高器件性能的原因主要归因于被暴露的导电沟道和微纳材料的性质。     

H2S气体传感器的进展

综述了Ｈ２Ｓ半导体气体传感器的制备及敏感机理，添加剂ＣｕＯ化合物可以明显提高对Ｈ２Ｓ气体的灵敏度与选择性，最后，介绍了一种似乎合理的敏感机制。     

背衬对压电传感器瞬态特性影响的模拟研究

接收信号在换能器压电层中的多次反射及波形转换对超声检测的灵敏度和分辨率有重要影响,提高其接收性能的关键是优化换能器背衬结构与材料参数.该文采用Ansys软件中力-电耦合瞬态模拟法,分析了背衬结构的几何参数、材料参数对压电直探头瞬态接收性能的影响,得到了压电换能器中不同时刻的弹性波场、电场分布及输出电压响应曲线,拟合了换能器灵敏度、分辨率与背衬结构几何、材料参数间的关系.研究结果表明,合理选择背衬结构与材料参数对消减接收信号的多次反射,提高换能器接收性能有明显的作用.运用有限元软件分析背衬结构对压电探头瞬态接收特性的影响,是优化背衬结构与材料参数重要方法之一.     

Response time and mechanism of Pd modified TiO2 gas sensor

In this work, gas response properties of Pd modified TiO₂ sensing films are discussed when exposed to H₂ and O₂. TiO₂ films are surface modified in PdCl₂-containing solution by the dipping method and treated for different treatment times to get different surface states. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and Kröger–Vink defect theory are used to characterize the sensing films. The gas response properties indicate that the sensor response time which related to the rate of change of sensor resistance is affected by the activation energy (E). In particular, the sensor treated at 900 °C for 2 h exhibits a response time of about 20–240 ms when exposed to H₂ and 40–130 ms when exposed to O₂ at 500–800 °C.     

Enhancing the Selectivity and Transparency of the Electron Contact in Silicon Heterojunction Solar Cells by Phosphorus Catalytic Doping

An intrinsic hydrogenated amorphous silicon (a-Si:H(i)) film and a doped silicon film are usually combined in the heterojunction contacts of silicon heterojunction (SHJ) solar cells. In this work, a post-doping process called catalytic doping (Cat-doping) on a-Si:H(i) is performed on the electron selective side of SHJ solar cells, which enables a device architecture that eliminates the additional deposition of the doped silicon layer. Thus, a single phosphorus Cat-doping layer combines the functions of two other layers by enabling excellent interface passivation and high carrier selectivity. The overall thinner layer on the window side results in higher spectral response at short wavelengths, leading to an improved short-circuit current density of 40.31 mA cm⁻² and an efficiency of 23.65% (certified). The cell efficiency is currently limited by sputter damage from the subsequent transparent conductive oxide fabrication and low carrier activation in the a-Si:H(i) with Cat-doping. Numerical device simulations show that the a-Si:H(i) with Cat-doping can provide sufficient field effect passivation even at lower active carrier concentrations compared to the as-deposited doped layer, due to the lower defect density.     

基于PANI/Au/Al2O3的丙酮气体传感器选择性及感测机理研究

以PANI为敏感材料,采用电聚合法制备PANI/Au/Al_2O_3电极,组装成感测系统,并以干燥的N_2为背景气体,对23～1189 ppm浓度范围的丙酮气体进行感测。分别添加O_2、CO_2、NH_3、水蒸气作为干扰气体进行选择性实验。结果表明,当以O_2或CO_2作为干扰气体时,该气体传感器的灵敏度均有所降低,但混合气体中丙酮的浓度与感测电极的电阻变化率仍具有良好的线性关系;当加入水蒸气(30%RH)或4 ppm氨气时,该丙酮气体传感器的电阻变化率分别稳定在5%和4%左右基本不变,不随丙酮气体浓度的改变而改变,说明该传感器受水分和氨气的干扰非常大。最后分别对PANI与丙酮、CO_2、NH_3、水蒸气进行反应的机理进行了分析。     

Transient Response of Twisted Wire Pairs Illuminated by HEMP

In this paper, the time domain characters of the response of twisted wire pairs (TWPs) excited by the high-altitude electromagnetic pulse (HEMP) have been proposed. The finite different time domain transmission line model (FDTD-TLM) method, which we have proposed previously, is used to calculate the terminal response of TWP. It shows that the time domain response includes two stages: The transient stage and damped stage. The transient stage is the key point of the coupling and protecting research. The influence factors of the transient stage have been analyzed. In the end, we obtain the changes of the induced voltage when the incident wave parameters and TWP parameters change.     

矩形光脉冲光电响应后沿拖曳性状研究

本文对矩形光脉冲光电响应后沿拖曳的形成机制进行了详尽的实验研究和理论分析，认为形成该光电响应时滞后曳的主要根源在于光生电子与空穴的多声子慢态复合．我们给出了削减后沿拖曳、提高光电响应速度的有效措施，从而促进解决宽带光通讯的速度瓶颈问题．     

Transient Response of a Deposit Excited by a Pulse of Current

Three-dimensional numerical models have been used to compute the transient response of an heterogeneity. The source is a pulse of current injected in the ground between two electrodes. In a first step the conductivity of the deposit is assumed to be a constant whatever the frequency. Then an induced polarization effect is taken into account by introducing a complex conductivity varying with ferquency. Changes in the late response of the anomaly are pointed out.     

气敏元件室温光激发气敏性能研究

研究了WO3掺杂的ZnO基气敏元件在紫外(UV)光激发下,对乙醇气体的室温气敏性能。结果表明:在UV光照射下,各元件在室温下对体积分数为100×10–6的乙醇气体显示了很好的光敏、气敏性能,响应、恢复时间均在8s以内,其中以掺杂X(WO3)为1%的元件W(1)为最佳,从而实现了室温下的气敏测试。     

气体传感器阵列中微加热器的发展现状

本文总结了气体传感器中微加热器的材料、结构及热特性，列举了常见的几种微加热器，对Ｐｔ加热器和多晶Ｓｉ加热器进行比较，并在此基础上简要介绍了传感器阵列中微加热器的制作及器阵列的气敏特性。     

光纤瓦斯传感系统研制

本文所讨论的是一种全光学、本安型光纤瓦斯传感系统。利用瓦斯气体在1.331μm的混合吸收带,按lambert定律与双波长差分吸收法,来探测大气中瓦斯气体的含量,由微机实现数据采集与处理,实时显示所测瓦斯浓度,精度可达0.025%。