Дисертації з теми "Formaldehyde sensors"
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Boddeti, Ravi Kumar. "Laser spectroscopy sensors for measurement of trace gaseous formaldehyde /." Connect to resource online, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1220624621.
Повний текст джерелаBoddeti, Ravi K. "Laser Spectroscopy Sensors for Measurement of Trace Gaseous Formaldehyde." Youngstown State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1220624621.
Повний текст джерелаDe, Smedt Isabelle. "Long-term global observations of tropospheric formaldehyde retrieved from spaceborne nadir UV sensors." Doctoral thesis, Universite Libre de Bruxelles, 2011. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209919.
Повний текст джерелаThis work reports on global observations of formaldehyde columns retrieved from the successive solar backscatter nadir sensors GOME, SCIAMACHY and GOME-2, respectively launched in 1995, 2002 and 2006. The retrieval procedure is based on the differential optical absorption spectroscopy technique (DOAS). Formaldehyde concentrations integrated along the mean atmospheric optical path are derived from the recorded spectra in the UV region, and further converted to vertical columns by means of calculated air mass factors. These are obtained from radiative transfer simulations, accounting for cloud coverage, surface properties and best-guess H2CO profiles, the latter being derived from the IMAGES chemistry transport model. A key task of the thesis has consisted in the optimisation of the H2CO retrieval settings from multiple sensors, taking into account the instrumental specificities of each sounder. As a result of these efforts, a homogeneous dataset of formaldehyde columns covering the period from 1996 to 2010 has been created. This comes with a comprehensive error budget that treats errors related to the spectral fit of the columns as well as those associated to the air mass factor evaluation. The time series of the GOME, SCIAMACHY and GOME-2 H2CO observations is shown to be consistent and stable over time. In addition, GOME-2 brings a significant reduction of the noise on spatiotemporally averaged observations, leading to a better identification of the emission sources. Our dataset is used to study the regional formaldehyde distribution, as well as its seasonal and interannual variations, principally related to temperature changes and fire events, but also to anthropogenic activities. Moreover, building on the quality of our 15-year time series, we present the first analysis of long-term changes in the H2CO columns. Positive trends, in the range of 1.5 to 4% yr-1, are found in Asia, more particularly in Eastern China and India, and are related to the known increase of anthropogenic NMVOC emissions in these regions. Finally, our dataset has been extensively used in several studies, in particular by the BIRA-IASB modelling team to constrain NMVOC emission fluxes. The results demonstrate the high potential of satellite data as top-down constraint for biogenic and biomass burning NMVOC emission inventories, especially in Tropical ecosystems, in Southeastern Asia, and in Southeastern US.
Le formaldéhyde (H2CO) joue un rôle central dans la chimie de la troposphère en tant que produit intermédiaire commun à la dégradation chimique de la plupart des composés organiques volatils dans l’atmosphère. L’oxydation du méthane est responsable de plus de la moitié de la concentration moyenne globale du formaldéhyde. Sur les continents en revanche, les hydrocarbures non-méthaniques (NMVOCs) émis par la végétation, les feux de biomasse et les activités humaines, augmentent de façon significative et localisée la concentration de H2CO. Les récents senseurs satellitaires à visée nadir offrent la possibilité de quantifier à l’échelle globale l’abondance du formaldéhyde dans la troposphère et de ce fait, d’améliorer notre connaissance des émissions de NMVOCs. Ceci est essentiel à la compréhension des mécanismes contrôlant la production et l’évolution de l’ozone troposphérique, élément clé pour la qualité de l’air et les changements climatiques, mais aussi du composé hydroxyle OH, le principal agent nettoyant de notre troposphère. C’est pourquoi, une méthode de plus en plus répandue pour améliorer les inventaires d’émissions des NMVOCs consiste en l’utilisation d’observations satellitaires de H2CO en combinaison avec un modèle de chimie et de transport troposphérique, dans une approche appelée modélisation inverse. Ce genre d’application demande des produits satellitaires bien caractérisés et dérivés de façon cohérente sur de longues périodes de temps.
Le travail présenté dans ce manuscrit porte sur l’inversion des colonnes de formaldéhyde à partir de spectres de la radiation solaire rétrodiffusée par l’atmosphère terrestre, mesurés par les senseurs GOME, SCIAMACHY et GOME-2, lancés successivement en 1995, 2002 et 2006. La méthode d’inversion est basée sur la spectroscopie d’absorption optique différentielle (DOAS). Les concentrations de formaldéhyde intégrées le long du chemin optique moyen dans l’atmosphère sont dérivées à partir des spectres mesurés, et ensuite transformées en colonnes verticales par le biais de facteurs de conversion appelés facteurs de masse d’air. Ces derniers sont calculés à l’aide d’un modèle de transfert radiatif, en tenant compte de la présence de nuages, des propriétés de la surface terrestre et la distribution verticale supposée du formaldéhyde, fournie par le modèle IMAGES. Un des objectifs principaux de la thèse a été d’optimiser les paramètres d’inversion pour H2CO, et ceci pour les trois senseurs, tout en tenant compte des spécificités de chaque instrument. Ces efforts ont conduit à la création d’un jeu de données homogène, couvrant la période de 1996 à 2010. Les colonnes sont fournies avec un bilan d’erreur complet, incluant les erreurs liées à l’inversion des concentrations dans les spectres, ainsi que celles provenant de l’évaluation des facteurs de masse d’air. La série temporelle des observations de GOME, SCIAMACHY et GOME-2 présente une bonne cohérence et stabilité sur toute la période. Nous montrons aussi que la meilleure couverture terrestre de GOME-2 entraîne une réduction significative du bruit sur les observations moyennées, permettant une meilleure identification des sources d’émission. Notre jeu de données est exploité pour étudier la distribution régionale du formaldéhyde, ainsi que ses variations saisonnières et interannuelles, principalement liées aux variations de température et aux feux de végétation, mais aussi aux activités anthropiques. De plus, en s’appuyant sur la qualité de la série temporelle de 15 ans, nous présentons la première analyse des variations à long terme des concentrations de H2CO. Des tendances positives, de l’ordre de 1.5 à 4% par an, sont observées en Asie, en particulier dans l’est de la Chine et en Inde, liées à l’augmentation des émissions anthropiques d’hydrocarbures dans ces régions. Finalement, nos données ont été largement exploitées par le groupe de modélisation de l’IASB pour faire des études de modélisation inverse des émissions de NMVOCs. Les résultats démontrent le haut potentiel des données satellitaires pour contraindre les inventaires d’émissions dues à la végétation et aux feux de biomasse, particulièrement dans les écosystèmes tropicaux, en Asie du sud-est, et dans le sud-est des Etats-Unis.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished
Alolaywi, Haidar. "Electrochemical MoOx/Carbon Nanocomposite Gas Sensor for Formaldehyde Detection at Room Temperature." University of Toledo / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1596821142716346.
Повний текст джерелаRavi, Srivathsan. "Continuous Monitoring and Removal of Formaldehyde Vapor in Ambient Air Using Polymer Catalyst Membranes." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1384428049.
Повний текст джерелаCuba, Supanta Gustavo. "Efectos del dopaje y la temperatura sobre las propiedades térmicas de hetero-estructuras de C/BN y su potencial uso como sensor ambiental del formaldehído." Doctoral thesis, Universidad Nacional Mayor de San Marcos, 2019. https://hdl.handle.net/20.500.12672/12312.
Повний текст джерелаConsejo Nacional de Ciencia y Tecnología (Perú). Fondo Nacional de Desarrollo Científico y Tecnológico (Fondecyt)
Tesis
Cindemir, Umut. "Thin films for indoor air monitoring : Measurements of Volatile Organic Compounds." Doctoral thesis, Uppsala universitet, Fasta tillståndets fysik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-302558.
Повний текст джерелаPaul, Mitchell Cameron. "Terahertz Molecular Spectroscopy as a Tool for Analytical Probing of Cellular Metabolism." Wright State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=wright1503928902745757.
Повний текст джерелаStewart, Katherine Mariann Elizabeth. "Doped Polyaniline for Gas Sensors for the Detection of Formaldehyde." Thesis, 2011. http://hdl.handle.net/10012/5852.
Повний текст джерелаHsieh, Ping-Ru, and 謝秉儒. "Fabrication of Micro Formaldehyde Gas Sensor." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/83767525429677899597.
Повний текст джерела大葉大學
機械工程研究所碩士班
94
ABSTRACT A novel micro formaldehyde gas sensor with a sputtered NiO thin film integrated with a micro hotplate was fabricated. A microfabricated formaldehyde gas sensor is developed which uses a silica substrate with Pt micro heaters as the micro hotplate and a thin-film NiO layer as a conductivity-sensitive material. The substrate is deposited with NiO thin film as sensing elements, Pt resistors as heaters, and as interdigitated electrodes for resistance measurement. As voltages were applied to Pt heaters, temperature of micro hotplates increased. Thus, at 300oC, when formaldehyde was present in the atmosphere, it was adsorbed and as a result the electrical conductivity of NiO films was increased. The measured resistance between the interdigitated electrodes was changed. The formaldehyde gas sensor was integrated with a Pt resistor as a micro heater for the enhancement of sensitivity. A high selectivity to acetone, methanol and ethanol was alson shown in the study.
Wu, Yan-Ting, and 吳耀庭. "The Gas Sensing Properties of Formaldehyde Gas Sensor." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/19042383532558951786.
Повний текст джерела國立屏東科技大學
材料工程所
95
Abstract Student ID:M9440007 Title of Thesis:The Gas Sensing Properties of Formaldehyde Gas Sensor Total Pages:67 Name of Institute:National Ping-Tung University of Science & Technology Name of Department:Department of Materials Engineering Date of Graduation:2007.07 Degree Conferred:Master Name of Student:Yan-Ting Wu Adviser:Lung-Ming Fu, Chia-Yen Lee The Contents of Abstract in this Thesis: The purpose of this study is to design and develop semiconductor-type Formaldehyde Gas Sensor by MEMS. This sensor is suitable not only for industrial process monitoring, but also for the detection of formaldehyde concentrations in buildings in order to act as the safeguard of the human’s health condition. In the present study, the glass substrate is used as a base, then upon this base, a sensing layer, a heating device and IDEs are integrated. The integrated micro-hotplates in the proposed design provide an instantaneous and precise temperature control capability. The current experimental results show that applied voltage of 5.2W yields a constant temperature of 300 ◦C. The range of formaldehyde detected of 40 to 8600 ppb that the time response of the gas sensor developed in the present study. The average time constant of the proposed formaldehyde gas sensor is determined to be 70s for formaldehyde concentrations in the range 0–3 ppm at a micro-hotplate temperature of 300 ◦C. The recovery time of the proposed formaldehyde gas sensor is determined to be 80s that sensitivity of 0.47kΩ/ppb at 300℃and a detection limit below 800ppb. The purpose of this study is to obtain the better sensitivity and the minimal monitoring concentration. The result of this experiment presented the difference of resistance of sensing layer is proportion to the concentration of formaldehyde. Keywords: formaldehyde, micro hotplate, NiO thin film, co-sputter
Lee, Pei-Yun, and 李佩芸. "The Development and Application of Portable Gaseous Formaldehyde Sensor." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/49116757296391129405.
Повний текст джерела國立中興大學
化學系所
102
In this study, we developed diverse electrochemical sensors based on electrodeposited various catalytic metal nanoparticles on a screen-printed edge band carbon ultramicroelectrode (SPUME) with Nafion as the solid polymer electrolyte. Uniform and well-dispersed metal-nanoparticles are well deposited on the SPUME without either protective or capped agents due to the edge diffusion effect at the SPUME. First part of this study was the development of portable gaseous formaldehyde amperometric sensor using the NPtRu-SPUME. The role of Ru was to protect the Pt from the poison of absorption of carbon monoxide. This developed gas sensing method for determination of formaldehyde showed a wide linear range from 25.4 ppb to 3.68 ppm, a very low detection limit of 1.42 ppb (S/N = 3) and excellent selectivity. Second, glycerol sensor based on the gaseous formaldehyde sensor has developed. The concentration of glycerol was determined indirectly by reacting glycerol with periodate to produce formaldehyde and formic acid. We used NAu-PtRu-SPUME here to dramatically enhance the sensitivity of glycerol determination. The developed method was successfully applied to identify the purity of glycerol in biodiesel. Overall, the glycerol sensor was found to be extremely highly sensitive and selective. Finally, we used lipase to indirectly quantified triglyceride concentration by glycerol sensing method.
Cheng, Chuangyuan, and 鄭創元. "Au/TiO2 Used in the Study of Formaldehyde Gas Sensor." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/08003572638488295704.
Повний текст джерела靜宜大學
應用化學系
101
This study is the use of precious metal aurum and titanium dioxide (TiO2) composite material formed as a formaldehyde gas sensors, for which surface characteristics and sensor response to be discussed . This study is based on the precious metal aurum and titanium dioxide (TiO2) material as a gas sensor , because it is very easy to make and has good environmental stability and high sensitivity . This study was conducted using impregnation method with different proportions of aurum titania mixed, boiled to dryness , after milling for 24 hours to complete the sensing material preparation to X-ray diffraction (XRD) , specific surface area measuring instrument (BET) , Transmission Electron Microscopy (TEM) , analysis of composite material surface characteristics. Sensor materials based on titanium dioxide, at room temperature, to detect formaldehyde 10 ppm, the sensor response is 6.1, reaction time (T90) 164 seconds, the response time (Tr90) 275 seconds, the study showed, with a doping 1% Au/TiO2 have the best material for the gas sensor sensing signals at room temperature, formaldehyde gas 10 ppm, up 20.6 sensing signal T90 was 66 s, Tr90 to 250 s, the sensing signal increased about three times more, the T90 and Tr90 also significantly reduced the precious metal aurum and titanium dioxide (TiO2) doped as composites formaldehyde gas sensors quite worth exploring.
Yang, Sung-Yuan, and 楊淞淵. "A solution-fabrication formaldehyde sensor based on graphene/PMMA composite materials." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/09182136572153294949.
Повний текст джерела國立臺灣大學
工程科學及海洋工程學研究所
103
In bottom layer of Internet of Things(M2M) , there would be a lot of sensors to detect our environment in several applications such as smart home and air monitoring . Air pollution influences human health and can cause a number of diseases.The one of major air pollutiants is volatile organic compounds (VOCs) especially in BTEX and formaldehyde can cause cancer to human beings .Therefore, developing a low cost,low power consumption and reliable gas sensor is very important for sensing technology. In this work ,we demonstrated graphene material blended with Poly(methyl methacrylate,PMMA,M=15,000) composite inks deposited between gold electrode by spin coating method .The deposited graphene composite films with different mixture concentration are sensing materials for VOCs chemiresister gas sensors in room temperature.The sensor response to several VOCs gas including methanol ,ethanol , acetone , benzene ,toluene , o-xylene, formaldehyde and water vapor are investigated. The sensors selectivity ,repeatability and stability,duration are also examined .The graphene material are prepared and selectively blended with PMMA both in dispersant Tetrahydrofuran(THF) to become conductive self-assembly composite materials . We also tested the difference of sensing VOCs characteristics between spin coated pure graphene films and graphene /PMMA composite films. The optional concentration of graphene composite spin coated films show good sensor response to formaldehyde vapor with resistance change about 0.5%~30% after exposing to each vapor concentration(about 10ppm~600ppm) in room temperature .We finally use instruments such as FTIR,SEM,XRD and Raman to analysis materials .We also infer the possible sensing mechanism between the graphene-PMMA composites and the formaldehyde.
LIU, CHENG-SYUAN, and 劉承軒. "A Study of TiO2 Polymeric Nanospheres Structure Used for Formaldehyde Gas Sensor." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/68204381013353731077.
Повний текст джерела靜宜大學
應用化學系
105
In this study, sensing material TiO2 polymeric nanospheres are prepared by hydrothermal synthesis from carbon spheres and titanium (IV) n-butoxide. For detecting formaldehyde gas, the sensing materials were characterized by X-ray Diffraction (XRD), high resolution surface area and porosimetry analyser (ASAP/BET), field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), energy dispersive spectrometer (EDS) and elemental analyzer. It exhibited a high response to 10 ppm at room temperature, response time (T90) is 74 seconds and recovery time (Tr90) is 102 seconds. It might be used in detecting formaldehyde gas and improve quality of air in the future.
Lin, Hsiu-Chia, and 林秀珈. "Fabrication of high sensitive and water- resistive humidity sensor by phenol formaldehyde resin and plasma treatment." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/11704602775200697202.
Повний текст джерела大同大學
材料工程學系(所)
94
For fabricating the excellent water-resistant humidity sensitive layer, the organic humidity sensitive monomer mixed with phenol-formaldehyde resin solution was successfully prepared by spin-coating on comb-shaped electrodes. The spin-coating sensitive layers were exposed to UV-light to induce grafting and curing reaction. Mixing with the resin solution cam improve the adhesion between the polymerized film and electrode substrate. Unfortunately, it tends to solve in water because the adhesion between the copolymerized monomer and electrode substrate is poor. When we deposit hydrophobic HMDSZ (hexamethyldisilazane) plasma film onto the comb-shaped electrodes as an interface before grafting, the plasma treatment can provide the free radicals that can bond with humidity-sensitive polymer strongly by graft reaction, therefore the device has a good water resistivity. The impedance can very by 4 order between humidity of35~95%. Temperature dependence, hystersis, response time, water durability under various environments were also investigated.
Liu, Li-Chia, and 劉力嘉. "Application ofpalladium and platinum electrodes prepared by electrochemical hydrogen bubble template technique in formaldehyde gas sensor." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/74034141410259247077.
Повний текст джерела國立勤益科技大學
化工與材料工程系
102
Formaldehyde sensor plays an important role in applications of industrial process and environmental monitorning. In this thesis, Nafion®/Pt (sputtering)/Ti/glass plate, Nafion®/Pd/Pt (sputtering)/Ti/glass plate and Nafion®/Pt/Pt(sputtering)/Ti/glass plateelectrodes are prepared by the microfabricationand the hydrogen bubble template techniques, which are used as the sensing electrodes of amperometric formaldehyde gas sensor. The characteristics of the preparing electrodes, the sensing properties and the aging phenomena of amperometric formaldehyde gas sensor are also investigated. The Pd/Pt(sputtering)/Ti/glass plate and Pt/Pt(sputtering)/Ti/glass plateelectrodes are electrodeposited by applying hydrogen bubble template technique with variable current densities and charges. The maximum electrochemical active areasand roughness factors of Pd/Pt(sputtering)/Ti/glass plate and Pt/Pt(sputtering)/Ti/glass plateelectrodes are obtainedto be 106.8 cm2 and 427.2, as well as 37.29 cm2 and 149.14 with the preparing current densities and charges of 0.15 and 0.05 A cm-2, as well as 12 and 12 C, respectively. Using the home-made electrodes as the sensing electrodes, the aging of amperometric formaldehyde gas sensors is caused by (1) the poisoning the electrodes by the strong adsorption of intermediates produced in the anodic oxidation of formaldehyde, and (2) retarding the mass transfer of formaldehyde caused by paraformaldehyde formed on the surface of Nafion®film. The sensing electrodes can be reactivated by (1) applying 0.9 and 0.8 V on the poisoning Pt and Pd electrodes for 3 min to oxidize the intermediates adsorbed on the electrode surface,and (2) depolymerizing the paraformaldehyde formed on the surface of Nafion film by passing90 ℃ N2 gasfor 20 min. When 1.25μl of the 5 wt% Nafion solution is used to prepared Nafion film on the sensing electrode, the maximum specific sensitivity of Nafion®/Pt (sputtering)/Ti/glass plate electrode is obtained to be 465.39 μA ppm-1g-1 for the amperometric formaldehyde operated at 200 ml min-1 100 RH% gas with 1 - 6 ppm formaldehyde. Using the same sensing conditions for the amperometric formaldehyde gas sensor, the maximum specific sensitivities of Nafion®/Pd/Pt (sputtering)/Ti/glass plate and Nafion®/Pt/Pt(sputtering)/Ti/glass plate electrodes are obtained to be 153.24and 147.24 μA ppm-1g-1, respectively, by using 3.5μl Nafion® solution to formaing the Nafion film on the sensing electrodes.
Nurpratama, Aditya Febry, and 艾迪耶. "Preparation of Nafion®/Pt/Au/Al2O3 Electrode Applied to Highly Sensitivity Amperometric Formaldehyde Gas Sensor." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/2h5fep.
Повний текст джерела國立勤益科技大學
化工與材料工程系
106
The sensing performances of a planar amperometric formaldehyde gas sensor based on the porous Pt electrode prepared with the hydrogen bubble dynamic template (HBDT) technique, and cast with Nafion film as the solid polymer electrolyte (SPE) are investigated in this thesis. The effect of temperature, concentrations of H2SO4 and H2PtCl6, charge passed (Qpt) and current density for preparing Pt sensing electrode on the characteristics and the sensing properties of the sensing electrode is investigated by using the conventional method. The conditions for the preparation of Pt sensing electrode are optimized by using the mixture design technique. The surface morphologies and crystallographic information of as-prepared electrode materials are analyzed by the FESEM and XRD, respectively. The electrochemical properties are investigated by the cyclic voltammetry (CV) and chronoamperometry technique. Based on the investigation with the conventional experimental technique, the maximum specific sensitivity of the amperometric HCHO gas sensor is obtained to be 20.37 μA ppm-1 mg-1 due to the higher specific electrochemical surface area (SECSA) (22.89 m2 g-1) of the porous Pt sensing electrode prepared in 0.0075 M H2PtCl6 and 0.05 M H2SO4 aqueous solution at 30 oC with QPt and the current density of 6 C and 0.075 A cm-2. The experimental results reveal that the specific sensitivity of the HCHO gas sensor are mainly affected by the concentration of H2PtCl6, Qpt and temperature for preparing Pt sensing electrode, which are optimized by using the mixture design technique. The relationship between the specific sensitivity of the HCHO gas sensor (Y) and the normalized [H2PtCl6] (X1), Qpt (X2) and temperature (X3) for preparing Pt sensing electrode is obtained to be Y = 17.24 X1 + 8.35X2 + 13.30X3 + 25.63X1X3 The maximum specific sensitivity of the HCHO gas sensor was obtained to be 23.44 μA ppm-1 mg-1 for preparing the Pt sensing electrode in 0.007 M H2PtCl6 and 0.05 M H2SO4 aqueous solution with QPt and the current density of 3.0 C and 0.075 A cm-2 at 31 oC. The mass transfer resistance of the HCHO gas sensor within the gas phase can be neglected for gas flow rate greater than 450 ml min-1. When the gas flow rate is fixed at 450 ml min-1, the specific sensitivity of the amperometric HCHO gas sensor is increased from 38.05 to 43.85 A ppm-1 mg-1 by decreasing the Nafion film thickness from 2.84 0.08 to 1.18 0.10 m due to the decrease in the mass transfer resistance within the Nafion film. The diffusivity of HCHO within the Nafion film is found to be 2.33 x 10-9 cm2 s-1. The fading fraction of the specific sensitivity of Nafion®/Pt/Au/Al2O3 sensing electrode is 32.3% for 5 sensing runs due to the formation of intermediates CO(ads) and HCOOH(ads) on the Pt sensing electrode surface. The effect of 1.33 ppm acetone, 70.71 ppm benzene, and 0.039 % CO2 on the selectivity of Nafion®/Pt/Au/Al2O3 sensing electrode is slight. The selectivity of the HCHO gas sensor is affected by the presence of 35 ppm ethanol and 20% O2 due to the oxidation of ethanol and reduction of O2 on the sensing electrode. The response time (t90) and detection limits of the Nafion®/Pt/Au/Al2O3 sensing electrode are obtained to be 240-325 s and 20 ppb, respectively, which is less than the legal levels of formaldehyde in the indoor air defined by WHO (World Health Organization) (80 ppb) for 30 min exposure limit.
Su, Yu-Hao, and 蘇于豪. "Development of GC-SS (Gas Chromatography - Semiconductor Sensor) Systems for Detection of Formaldehyde and TVOCs in Healthy Green Building Materials." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/20362745696313793172.
Повний текст джерела國立屏東科技大學
材料工程所
98
The purpose of study to apply MEMS techniques to design and manufacture a micro-column-based GC chip which have the same effect of GC capillaries and SS(Semiconductor Sensor) Chips with deposited oxide layer for detecting formaldehyde and TVOCs, which may afterward connect the GC chip. The developed platform technologies can separate mixing samplein the GC chip and detects their species and concentrations in the SS chips. This study exploits the realization of wet-etched micro columns for GC chip and SS chip. The leakage test and mixture gas separate test achieved a fruitful separate result for Ethylbenzene-Xylene mixture at 17.1 cm/s linear flow rate in GC chip column that thermal bound with Pyrex 7740 glass wafer and polar content coating. The E-beam evaporation and sputtering techniques are used to deposit inter-digitized electrodes (IDEs) and sensing layer of SS chip receptivity. It also was considered the sensing characteristics of before and after bounded cover plate.