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1
MacGibbon, Rebecca Mary Alice. « Designer nano-composite materials with tailored adsorption and sensor properties ». Thesis, University of Surrey, 2006. http://epubs.surrey.ac.uk/844469/.
Texte intégralRésumé :
This thesis is concerned with the possibility of producing novel materials by the sol-gel method that could be incorporated into a new sensing system to be used for the detection of hydrocarbons, in particular methane. Possibilities for a new system include coating optical fibres, at pre-determined points, with a material that causes some sort of disruption in the signal of the fibre when in contact with a hydrocarbon or specifically methane. Dip coating an optical fibre with a sol-gel would be a method for producing an optical fibre based system. This would provide variable chemistry, refractive index and hydrocarbon sensitivity. New silica-based sol-gel materials are presented and titania is incorporated to some of these materials in order to improve the catalytic potential of the system and to increase the refractive index. In order to increase the hydrophobicity and elasticity of the final coatings, organic modifiers are added. The sol-gel materials are characterised by a variety of techniques as both monoliths and thin films. Along with the characterisation, the samples are analysed to determine their potential to adsorb methane and water and the possibility of incorporating the samples in to an optical fibre sensor system utilising ultra-violet/visible spectroscopy. The presence of titania and/or organic modifiers in a silica based sol-gel system are seen to increase significantly the extent of methane adsorption and decrease the extent of water sorption at 293-298 K. It appears that having both titania and organic modifier gives a bigger effect on adsorption than either one alone. The reasons for this are considered in detail.
2
George, Anoop. « CHARACTERISTICS AND APPLICATIONS OF A SCANNING NANO-SLIT OPTICAL SENSOR ». Diss., The University of Arizona, 2011. http://hdl.handle.net/10150/195864.
Texte intégralRésumé :
In this dissertation, imaging characteristics of a nano-slit are investigated. Applications of a scanning and rotating nano-slit in measuring sub-micron aerial features are demonstrated. Coherent sub-micron spot distributions are reconstructed with a very high contrast. Finally, high NA partially coherent images with features as small as 210 nm half-pitch are reconstructed and the ultimate resolution of the system is determined.A nano-slit is characterized as a sensor for coherent line-and-space features. Experiments and simulation verify image detection with contrasts greater than 0.9. Effects of polarization on imaging performance are reported. A scanning and rotating nano-slit in conjunction with a filtered back-projection technique is used to reconstruct sub-micron coherent spot distributions. Simulation results show very good agreement with the experiment. Further, it is shown that the reconstruction is very resilient to some common random experimental errors.Imaging characteristics of a scanning nano-slit sensor are determined for high NA partially coherent images. Good imaging performance (contrast > 0.8) is demonstrated with line-and-space images up to a spatial frequency of 2.38 lp / micron. Sub-micron features in a high NA partially coherent image are measured with a scanning and rotating nano-slit. A modified microscope is used to create the measured features, including 210 nm half-pitch features that cannot be imaged using the microscope in a conventional imaging mode. Using the filtered back projection technique, two-dimensional sub-micron features are reconstructed by the nano-slit sensor. It is determined that the resolution limit of ~ 200 nm is determined by the reconstruction technique and not by the width of the nano-slit.
3
Zhang, Tan Tan. « Nano-watt class CMOS interface circuits for wireless sensor nodes ». Thesis, University of Macau, 2018. http://umaclib3.umac.mo/record=b3952097.
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4
Kurth, Martin L. « Plasmonic nanofocusing and guiding structures for nano-optical sensor technology ». Thesis, Queensland University of Technology, 2018. https://eprints.qut.edu.au/118670/1/Martin_Kurth_Thesis.pdf.
Texte intégralRésumé :
This thesis investigated factors affecting the sensitivity of nano-optical sensors that could be used for the detection of trace amounts of explosives and environmental pollutants in air. By delivering air to regions of enhanced electric field produced by metallic nanostructures, as well as using structures that localise and guide light at nanoscale levels, detection limits can be reduced.
5
Andio, Mark Anthony. « Sensor Array Devices Utilizing Nano-structured Metal-oxides for Hazardous Gas Detection ». The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1343155831.
Texte intégral
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ZHU, XIAOSHAN. « NANO ELECTROCHEMICAL SENSOR AND ITS MEASUREMENT ELECTRONICS WITH A DYNAMIC TRANSDUCTION MECHANISM ». University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1122989975.
Texte intégral
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SAMARAO, ASHWIN K. « AMPEROMETRIC CHARACTERIZATION OF A NANO INTERDIGITATED ARRAY (nIDA) ELECTRODE AS AN ELECTROCHEMICAL SENSOR ». University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1154451638.
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Abegão, Luis Miguel Gomes. « Desenvolvimento de um sensor para detecção de nano e micro concentrações de deltametrina ». Master's thesis, Faculdade de Ciências e Tecnologia, 2012. http://hdl.handle.net/10362/7990.
Texte intégralRésumé :
Dissertação para obtenção do Grau de Mestre em
Engenharia FísicaA ampla utilização de produtos fitofarmacêuticos nas produções agrícolas, em particular a utilização constante de um dos insecticidas cuja substância activa é a deltametrina, são uma fonte de contaminação dos solos e dos sistemas aquáticos adjacentes às produções agrícolas, havendo necessidade de criar sensores que detectem esta substância em quantidades ínfimas. Assim, neste trabalho foi desenvolvido um sensor que permite a detecção de concentrações da ordem dos nano e micro molar de deltametrina em solução de etanol. Este sensor é constituído por eléctrodos interdigitais de ouro depositados num suporte sólido de vidro comum, sobre o qual é adsorvido uma camada sensorial polimérica de poli(cloreto de alilamina) (PAH) e de poli[1-[4-(3-carboxi-4-hidroxifenilazo)-benzenesulfonamida)-1,2-etanodiil] sal de sódio] (PAZO) através da técnica de automontagem. Este sensor foi caracterizado por espectroscopia de impedância, microscopia óptica, espectrofotometria ultravioleta-visível e microbalança de cristal de quartzo. Os resultados permitiram verificar que o sensor permite detectar concentrações da ordem dos nano e micro molar através da medição da parte real da impedância, a uma frequência fixa de 100 Hz, apresentando um comportamento linear por década de concentração. Este sensor apresenta uma sensibilidade de 41.1 ± 0.7 kΩ por década de concentração, para um tempo de imersão superior a 2 minutos e um erro de reprodutibilidade de 2%.
9
Nazarious, Miracle Israel. « Design, Development and Characterization of a Digital Sun Sensor prototype for Nano Satellite Applications ». Thesis, Luleå tekniska universitet, Rymdteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-59501.
Texte intégralRésumé :
Sun sensors serve as eyes of satellites. It is one of the basic components in satellites used for the purpose of determining the position of the sun in order to properly orient the solar arrays. The technological challenge involved in such sensors is to find the right balance between the field-of-view and the accuracy characteristics. For every sun sensor, there is a trade-off between these two performance parameters which has to be optimized for the expected performance requirements. Developing a low-weight, low-power sun sensorfor nano-satellite applications managing better performance in terms of field-of-view and accuracy is the challenge, this project has accepted to address. The true motivation behind this project was to develop an advanced solar-powered, bluetooth enabled digital sun sensor entitled as Multihead Autonomous Wireless Digital Sun Sensor (MAWDSS). To reach this ambitious goal, the footpath to be followed includes developing a prototype of a digital sun sensor and an autonomous wireless digitalsun sensor leading to the final product. This thesis work lays the first step and proposes a design of a digital sun sensor using low-cost commercial-off-the-shelf (COTS) components, develop a prototype and conduct performance characterization to compare with a commercial benchmarking sun sensor.The desired performance requirements were predefined prior to describing the detailed design aspects of the sun sensor. The problems encountered during experimental testing and the recommended suggestions to overcome them are presented. This thesis defines a complete product development life cycle involving skills from all three aspects of engineering: mechanical, electrical and programming. Each individual regime of the project are properly addressed with relevant figures and plots in separate chapters for the ease of following the report.
10
Zhang, Peng. « DESIGN AND FABRICATION OF CHEMIRESISTOR TYPEMICRO/NANO HYDROGEN GAS SENSORS USINGINTERDIGITATED ELECTRODES ». Doctoral diss., University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2814.
Texte intégralRésumé :
Hydrogen sensors have obtained increased interest with the widened application of hydrogen energy in recent years. Among them, various chemiresistor based hydrogen sensors have been studied due to their relatively simple structure and well-established detection mechanism. The recent progress in micro/nanotechnology has accelerated the development of small-scale chemical sensors. In this work, MEMS (Micro-Electro-Mechanical Systems) sensor platforms with interdigitated electrodes have been designed and fabricated. Integrating indium doped tin dioxide nanoparticles, these hydrogen sensors showed improved sensor characteristics such as sensitivity, response and selectivity at room temperature. Design parameters of interdigitated electrodes have been studied in association with sensor characteristics. It was observed that these parameters (gap between the electrodes, width and length of the fingers, and the number of the fingers) imposed different impacts on the sensor performance. In order to achieve small, robust, low cost and fast hydrogen micro/nano sensors with high sensitivity and selectivity, the modeling and process optimization was performed. The effect of humidity and the influence of the applied voltage were also studied. The sensor could be tuned to have high sensitivity (105), fast response time (10 seconds) and low energy consumption (19 nW). Finally, a portable hydrogen instrument integrated with a micro sensor, display, sound warning system, and measurement circuitry was fabricated based on the calibration data of the sensor.Ph.D.
Department of Mechanical, Materials and Aerospace Engineering
Engineering and Computer Science
Mechanical Engineering PhD
11
Shenoy, Sukesh. « Design, simulation and analysis of a molecular nano-sensor operating at terahertz frequencies for energetic materials ». Thesis, Texas A&M University, 2003. http://hdl.handle.net/1969.1/5786.
Texte intégralRésumé :
Nano-sensors, as an application of nanotechnology, are extremely important for environmental, medical and security applications. Terahertz science is an exciting new field that is set to impact the field of sensing to a large extent. I proposed to combine the fields of nanotechnology and terahertz science and develop a molecular nano-sensor that operates at terahertz frequencies. I focused our sensing on energetic materials, particularly nitromethane, and conducted an extensive analysis on its frequency spectrum. The study also focused on designing the nano-sensor and determining its terahertz operation characteristics. I subjected it to various conditions through the use of molecular dynamics simulations. Finally we analyzed the simulation results and provided a proof of the concept that we had a working molecular nano-sensor that operates at terahertz frequencies and senses energetic materials. The results from the frequency analysis of nitromethane showed that the frequency characteristics determined from our simulations were in close agreement with the ones determined experimentally. In addition to this we also successfully demonstrated the use of a Lennard Jones potential to model the CN bond scission of nitromethane. Finally, the results from the interactions between the nano-sensor and nitromethane showed that the presence of nitromethane causes sufficient change in the terahertz frequency characteristics of the nano-sensor providing a means to detect nitromethane.
12
Farzinpour, Pouyan. « DYNAMIC TEMPLATING : A NEW PATHWAY FOR THE ASSEMBLY OF LARGE-AREA ARRAYS OF PLASMONIC, MAGNETIC AND SEMICONDUCTOR NANOMATERIALS ». Diss., Temple University Libraries, 2014. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/280637.
Texte intégralRésumé :
Mechanical EngineeringPh.D.
Substrate-based nanostructures are of great importance due to their applications in microelectronic devices, chemical sensors, catalysis and photovoltaics. This dissertation describes a novel fabrication technique for the formation of periodic arrays of substrate-based nanoparticles. The prescribed route, referred to as dynamic templating, requires modest levels of instrumentation consisting of a sputter coater, micrometer-scale shadow masks and a tube furnace. The route has broad applicability, having already produced periodic arrays of gold, silver, copper, platinum, nickel, cobalt, germanium and Au-Ag alloys on substrates as diverse as silicon, sapphire, silicon-carbide, and glass. The newly devised method offers large-area, high-throughput capabilities for the fabrication of periodic arrays of sub-micrometer and nanometer-scale structures and overcomes a significant technological barrier to the widespread use of substrate-based templated assembly by eliminating the need for periodic templates having nanoscale features. Because this technique only requires modest levels of instrumentation, researchers are now able to fabricate periodic arrays of nanostructures that would otherwise require advanced fabrication facilities.
Temple University--Theses
13
蔡紫珊 et Tsz-shan Jacqueline Choy. « Enhancing the sensitivity and specificity of piezoelectric quartz crystal sensor by nano-gold amplification and molecularly imprintingtechnologies ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B39558575.
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Deshpande, Sameer Arun. « DIMESIONALITY ASPECTS OF NANO MICRO INTEGRATED METAL OXIDE BASED EARLY STAGE LEAK DETECTION ROOM TEMPERATURE HYDROGEN SENSOR ». Doctoral diss., University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2131.
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Detection of explosive gas leaks such as hydrogen (H2) becomes key element in the wake of counter-terrorism threats, introduction of hydrogen powered vehicles and use of hydrogen as a fuel for space explorations. In recent years, a significant interest has developed on metal oxide nanostructured sensors for the detection of hydrogen gas. Gas sensors properties such as sensitivity, selectivity and response time can be enhanced by tailoring the size, the shape, the structure and the surface of the nanostructures. Sensor properties (sensitivity, selectivity and response time) are largely modulated by operating temperature of the device. Issues like instability of nanostructures at high temperature, risk of hydrogen explosion and high energy consumption are driving the research towards detection of hydrogen at low temperatures. At low temperatures adsorption of O2- species on the sensor surface instead of O- (since O- species reacts easily with hydrogen) result in need of higher activation energy for hydrogen and adsorbed species interaction. This makes hydrogen detection at room temperature a challenging task. Higher surface area to volume ratio (resulting higher reaction sites), enhanced electronic properties by varying size, shape and doping foreign impurities (by modulating space charge region) makes nanocrystalline materials ideal candidate for room temperature gas sensing applications. In the present work various morphologies of nanostructured tin oxide (SnO2) and indium (In) doped SnO2 and titanium oxide (titania, TiO2) were synthesized using sol-gel, hydrothermal, thermal evaporation techniques and successfully integrated with the micro-electromechanical devices H2 at ppm-level (as low as 100ppm) has been successfully detected at room temperature using the SnO2 nanoparticles, SnO2 (nanowires) and TiO2 (nanotubes) based MEMS sensors. While sensor based on indium doped tin oxide showed the highest sensitivity (S =Ra/Rg= 80000) and minimal response time (10sec.). Highly porous SnO2 nanoparticles thin film (synthesized using template assisted) showed response time of about 25 seconds and sensitivity 4. The one dimensional tin oxide nanostructures (nanowires) based sensor showed a sensitivity of 4 and response time of 20 sec. Effect of aspect ratio of the nanowires on diffusion of hydrogen molecules in the tin oxide nanowires, effect of catalyst adsorption on nanowire surface and corresponding effect on sensor properties has been studied in detail. Nanotubes of TiO2 prepared using hydrothermal synthesis showed a sensitivity 30 with response time as low as 20 seconds where as, TiO2 nanotubes synthesized using anodization showed poor sensitivity. The difference is mainly attributed to the issues related to integration of the anodized nanotubes with the MEMS devices. The effect of MEMS device architecture modulation, such as, finger spacing, number and length of fingers and electrode materials were studied. It has been found that faster sensor response (~ 10 sec) was observed for smaller finger spacing. A diffusion model is proposed for elucidating the effect of inter-electrode distance variation on conductance change of a nano-micro integrated hydrogen sensor for room temperature operation. Both theoretical and experimental results showed a faster response upon exposure to hydrogen when sensor electrode gap was smaller. Also, a linear increase in the sensor sensitivity from 500 to 80000 was observed on increasing the electrode spacing from 2 to 20 μm. The improvement in sensitivity is attributed to the higher reactive sites available for the gaseous species to react on the sensor surface. This phenomenon also correlated to surface adsorbed oxygen vacancies (O-) and the rate of change of surface adsorbed oxygen vacancies. This dissertation studied in detail dimensionality aspects of materials as well as device in detecting hydrogen at room temperature.Ph.D.
Department of Mechanical, Materials and Aerospace Engineering
Engineering and Computer Science
Materials Science & Engr PhD
15
Dhane, Kedar. « IN-SITU ELECTRO-CHEMICAL RESIDUE SENSOR AND PROCESS MODEL APPLICATION IN RINSING AND DRYING OF NANO-STRUCTURES ». Diss., The University of Arizona, 2010. http://hdl.handle.net/10150/195656.
Texte intégralRésumé :
Typical surface preparation consists of exposure to cleaning chemical to remove contaminants followed by rinsing with ultra-pure water which is followed by drying. Large quantities of water, various chemicals, and energy are used during rinsing and drying processes. Currently there is no in-situ metrology available to determine the cleanliness of micro- and nano-structures as these processes are taking place. This is a major technology gap and leads to over use of resources and adversely affects the throughput.Surface preparation of patterned wafers by batch processing becomes a major challenge as semiconductor fabrication moves deeper in submicron technology nodes. Many fabs have already employed single wafer tools. The main roadblock for single-wafer tools is their lower throughput. This obstacle is eased by introduction of multi chamber tools. To reduce cycle time and resource utilization during rinse and dry processes without sacrificing surface cleanliness and throughput, in-situ metrology is developed and used to compare typical single wafer spinning tools with immersion tools for rinsing of patterned wafers. This novel metrology technology includes both hardware for an in-situ measurement and software for process data analysis. Successful incorporation of this metrology will eliminate dependency on external analysis techniques such as Inductively Coupled Mass Spectroscopy (ICPMS), Scanning Electron Microscope (SEM), and Tunneling Electron Microscope (TEM), and will lead to fast response time.In this study the electro-chemical residue sensor (ECRS) was incorporated in a lab scale single-wafer spinning and single- wafer immersion tool. The ECRS was used to monitor dynamics of rinsing of various cleans such as ammonium peroxide mixture (APM), hydrochloric peroxide mixture (HPM), and sulfuric peroxide mixture (SPM). It was observed that different cleaning chemicals impact the subsequent rinse not only through adsorption and desorption but also through surface charge. The results are analyzed by using a comprehensive process model which takes into account various transport mechanisms such as adsorption, desorption, diffusion, convection, and surface charge. This novel metrology can be used at very low concentration with very high accuracy. It is used to study the effect of the key process parameters such as flow rate, spin rate, temperature, and chemical concentration.
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Vatani, Morteza. « Additive Manufacturing of Stretchable Tactile Sensors : Processes, Materials, and Applications ». University of Akron / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1436202948.
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Zaffino, Rosa Letizia. « Development of a nano sensor for direct-electric free-label detection of DNA’s hybridization and single nucleotide polymorphism ». Doctoral thesis, Universitat de Barcelona, 2015. http://hdl.handle.net/10803/384708.
Texte intégralRésumé :
The search for analytical tools suitable for wide-scale application of DNA analysis is an hot research topic, although thanks to well-established microarray based technology, analysis of DNA sequences and SNP detection can be worked out through a fairly laboratory routine.
DNA analysis has nowadays become of increasing interest for several different purposes, mainly thanks to the successful employment of microarray technology, characterized by high sensitiveness and high-throughput analysis, which rapidly advanced genetics leading to devel- opment of many fields of application of DNA analysis, which keeps high the trend in alternative technologies, which could overcome inherent limitations of microarrays technology.
In this regard, many efforts have been spent to study electrochemical/electrical based detection strategies by means of which it could be possible to accomplish sensitive analysis by using portable equipments, cheaper and more practical than optical ones, and with scalable-devices compatibles with standard microelectronic processing.
Emerging nano-probes with increased chemical-physical properties are considered with growing interest in DNA biosensors as ideal candidates to enhance electrochemical/electrical based detection systems. Among these, nano-gaps adjusted to fit DNA, or in general analyte molecules sizes, are very promising because they can enable direct electrical detec- tion schemes, thus providing a straightforward electronic analogue of the successful DNA microarray standard.
Electrical properties of DNA have been the principal focus of many experimental and theoretical research, since early experimental founding confirmed an old hypothesis, for its relevance in the biological function of DNA, being related both with damage and base repair, but also for the appealing potential for biosensor and, in general, in bioelectronic applications.
Thanks to its peculiar interactions, it allows versatile manipulations of the structure, compared to other organic and synthetic polymers which have been considered for such purposes. Even though many questions still are open on electrical properties of DNA, it is generally accepted that DNA's conductivity is intimately linked with details of the sequences involved, its length and the overall environment in which molecule is found. The sensitivity to structure's alteration, as that induced by the presence of a mutation, confirmed by experimental and theoretical works allows to exploit DNA electrical properties for biosensor applications.
Relying on this agreed description of DNA electrical properties features, the general aim of this thesis was to explore the possibility of developing a platform for the direct transduction of DNA hybridization event based on a nano-gap device and electrical signaling enabled by long range electron transport through DNA molecules.La detección de hibridación de cadenas de ADN es un reto relevante científicamente y tecnológicamente, que puede aprovechar de las posibilidades proporcionadas por los alcances en los procesos de nano fabricación y caracterización, inspiradores de la idea de una medicina en el punto de atención. El propósito de este trabajo es de establecer un sistema de detección de hibridación de ADN, y polimorfismo de un solo nucleótido (SNP), basado en la medida eléctrica de la reasistencia de un nano-gap funcional izado con el ADN diana. El desarrollo y test del sistema se ha llevado a cabo fijando diferentes objetivos. Un estudio preliminar de la literatura relacionada con las propiedades eléctricas del ADN se ha conducido con la finalidad de establecer el marco de factibilidad del proyecto. De acuerdo con los resultados de este estudio ha sido posible idear el sistema y optimizar su eficacia respeto a las experiencias reportadas. Fijar una estrategia de fabricación de los dispositivos capaz de proveer nano-gaps aptos a la medida de conductividad muy baja, según una rutina de fácil implementación y con alta reproducibilidad de los resultados. Estos se han caracterizados mediante el utilizo de diferentes técnicas basadas primariamente en métodos de detección Óptica y Eléctrica/Electro-química. Obtener la bio-funcionalización selectiva de los electrodos en el nano-gap testando y caracterizando métodos diferentes. Probar el principio de funcionamiento del sistema a través de la medida de la conductividad en los nano-gap durante las diferentes etapas de funcionalización con los bio-receptores y el DNA target. Optimizar el sensor testando su selectividad respeto a la presencia de mutaciones, la sensibilidad a medir diferentes concentraciones del target, y finalmente la posibilidad de regeneración del dispositivo después desnaturalización del ADN hibridado
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Choy, Tsz-shan Jacqueline. « Enhancing the sensitivity and specificity of piezoelectric quartz crystal sensor by nano-gold amplification and molecularly imprinting technologies ». Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/HKUTO/record/B39558575.
Texte intégral
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Savary, Eric. « Conception et intégration d'une électronique de conditionnement pour un capteur audio à base de nano-fils de silicium ». Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4716.
Texte intégralRésumé :
Les microphones sont des capteurs qui permettent à nos systèmes électroniques de prendre connaissance de notre environnement acoustique en fournissant un signal électrique représentatif des vibrations de l’air. Ils sont employés dans la plupart des systèmes multimédia, mais aussi dans les appareils auditifs. Dans l’implant auditif, le microphone se substitue à l’oreille humaine capable de détecter des pressions acoustiques variants de quelque μPa à quelques Pa. Les microphones, sont en général accompagnés d’un circuit électronique spécifique qui permet leur exploitation au coeur d’un système hétérogène. Depuis les toutes premières transductions acoustique-électriques, le microphone a été perfectionné avec la mise en oeuvre de nouveau principes de transduction et l’élaboration de circuit de conditionnement plus performants. Dernièrement, l’introduction de la technologie MEMS (Micro Electro Mechanical Systems) a permis de réaliser des microphones extrêmement compacts et peu couteux. Ces travaux de recherches concernent la réalisation d’un circuit électronique dédié à l’exploitation d’un transducteur M&NEMS (Micro & Nano Electro Mechanical Systems) survenant comme une évolution du MEMS. Pour commencer l’étude, le principe de transduction et l’application du microphone sont étudiés. Les circuits existants sont examinés en détail et adaptés au transducteur M&NEMS. Les résultats potentiels sont discutés et situés dans l’application. Dans un second temps, un circuit de conditionnement spécifique est proposé. Les résultats sont présentés puis le circuit électronique dédié est intégré sur silicium. Les performances des blocs fonctionnels intégrés sont mesurées et présentéesMicrophones are sensors which allow gauging acoustic environment through an electric representation of vibrations in the air. They can be found in most multimedia equipment and in hearing aids. In this particular application, microphone substitutes a human ear which is able to sense pressure level of sound ranging from a μPa to few Pa. The read-out circuit of microphones converts physical signal from transducer into electronic signals that can be used in any heterogeneous system involving audio processing. Transducers of microphones have known successive generation of improvement. The latest refinement is related to the emergence of MEMS (Micro Electro Mechanical Systems) technology which is suitable to build compact sensor. This thesis explores the design of a readout-circuit using an innovative M&NEMS (Micro & Nano Electro Mechanical Systems) technology derived from MEMS. The thesis is structured beginning with review of existing circuits for M&NEMS microphone. A comparative study is reported considering the proposed technical specifications using simulations and a prototype was realized using discrete components. In the second phase, an innovative circuit was proposed as an ASIC solution targeting M&NEMS technology developed at CEA-LETI. The performance evaluation and the physical measurements of the proposed ASIC are detailed
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Banishev, A. A., A. A. Lotin et A. F. Banishev. « Deformation Stimulated Luminescence of Nano-micro-parcticles SrAl2O4:(Eu2+, Dy3+) in a Matrix of Photopolymer and Creation of Sensor Elements of Mechanical Stresses ». Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35389.
Texte intégralRésumé :
The work deals with low-temperature photoluminescence and deformation luminescence (mechanolu-minescence) of a composite material based on fine disperse powder of phosphor SrAl2O4:(Eu2+, Dy3+) and photopolymerizing resin that is transparent in the visible region. It has been shown that at the low tem-perature (T=15÷200 K) the photoluminescence spectrum of SrAl2O4:(Eu2+, Dy3+) displays two wide, partial-ly overlapping bands with the maxima at λ1max517 nm and λ2max446 nm. The short-wave luminescence band (λ2max446 nm) has been found to undergo temperature quenching and to completely decay at T200 K. A mechanism of mechanoluminescence excitation has been suggested. It has been shown that the com-posite material exhibits high sensitivity to mechanical action.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35389
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Fechete, Alexandru Constantin, et e54372@ems rmit edu au. « Layered Surface Acoustic Wave Based Gas Sensors Utilising Nanostructured Indium Oxide Thin Layer ». RMIT University. Electrical and Computer Engineering, 2009. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20091105.141111.
Texte intégralRésumé :
Planar two-dimensional (2-D) nanostructured indium oxide (InOx) and one-dimensional (1-D) tin oxide (SnO2) semiconductor metal-oxide layers have been utilised for gas sensing applications. Novel layered Surface Acoustic Wave (SAW) based sensors were developed consisting of InOx/SiOxNy/36°YXLiTaO3, InOx/SiNx/SiO2/36°YXLiTaO3 and InOx/SiNx/36°YXLiTaO3 The 1 µm intermediate layers of silicon oxynitride (SiOxNy), silicon nitride (SiNx) and SiO2/SiNx matrix were deposited on lithium tantalate (36°YXLiTaO3) substrates by r.f. magnetron sputtering, electron-beam evaporation and plasma enhanced chemical vapour deposition (PECVD) techniques, respectively. As a gas sensitive layer, a 100 nm thin layer of InOx was deposited on the intermediate layers by r.f. magnetron sputtering. The targeted gases were ozone (O3) and hydrogen (H2). An intermediate layer has multiple functions: protective role for the interdigital transducers' electrodes as well as an isolating effect from InOx sensing layer, thereby improving the sensor performance. The developed SAW sensors' exhibited high response magnitudes with repeatable, reversible and stable responses towards O3 and H2. They are capable of sensing concentrations as low as 20 parts-per-billion for O3 and 600 parts-per-million for H2. Additionally a conductometric type novel sensing structure of SnO2/36°YX LiTaO3 was also developed by depositing a thin layer of SnO2 nanorods by PECVD. The gas sensing performance exhibited repeatable, reversible, stable responses towards NO2 and CO. The surface morphology, crystalline structure and preferred orientation of the deposited layers were investigated by Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD). A polycrystalline, oxygen deficient non-stoichiometric InOx with grain sizes of 20-40 nm was revealed. The 1-D nanostructures were characterised by Transmission Electron Microscopy (TEM) showing nanorods with needle-like shape , diameters of 10-20 nm a t the top and 30-40 nm at the base as well as a preferential growth orientation of [ ] on the LiTaO3 substrate. The developed sensors are promising for O3, H2 and CO sensing.
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SCARPA, ANTONIO. « Sensori nano-gravimetrici : riduzione del fattore umidità mediante polimeri porosi superficiali ». Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2009. http://hdl.handle.net/2108/1094.
Texte intégralRésumé :
One of the highest interfering for the determination of VOC's in the sensoristic' s field, is the
humidity. in this thesis my aim is to develop a physic system able of to reduce the humidity factor.
For this reason has been tested the influence of humidity against some nano-gravimetric sensors
based on of quartz oscillating with fundamental frequency of 20 MHz, with surface modified with
Me-porphyrines and Me-corroles with Langmuir-Schaefer technique (LS) before and after the
deposition of six layers of Poly-methyl methacrylate porous (PMMA).
The decrease of sensibility' s against the humidity in sensor modified in surface with PMMA
porous, compared to the same unmodified, observed in the tests, carried out us to assert, that this
method could be useful for the future development of sensors that isn' t influenced of humidity.
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Elhag, Sami. « Chemically Modified Metal Oxide Nanostructures Electrodes for Sensing and Energy Conversion ». Doctoral thesis, Linköpings universitet, Institutionen för teknik och naturvetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-134275.
Texte intégralRésumé :
The goal of this thesis is the development of scalable, low cost synthesis of metal oxide nanostructures based electrodes and to correlate the chemical modifications with their energy conversion performance. Methods in energy conversion in this thesis have focused on two aspects; a potentiometric chemical sensor was used to determine the analytical concentration of some components of the analyte solution such as dopamine, glucose and glutamate molecules. The second aspect is to fabricate a photo-electrochemical (PEC) cell. The biocompatibility, excellent electro-catalytic activities and fast electron transfer kinetics accompanied with a high surface area to volume ratio; are properties of some metal oxide nanostructures that of a potential for their use in energy conversion. Furthermore, metal oxide nanostructures based electrode can effectively be improved by the physical or a chemical modification of electrode surface. Among these metal oxide nanostructures are cobalt oxide (Co3O4), zinc oxide (ZnO), and bismuth-zincvanadate (BiZn2VO6) have all been studied in this thesis. Metal oxide nanostructures based electrodes are fabricated on gold-coated glass substrate by low temperature (< 100 0C) wet chemicalapproach. X-ray diffraction, x-ray photoelectron spectroscopy and scanning electron microscopy were used to characterize the electrodes while ultraviolet-visible absorption and photoluminescence were used to investigate the optical properties of the nanostructures. The resultant modified electrodes were tested for their performance as chemical sensors and for their efficiency in PEC activities. Efficient chemically modified electrodes were demonstrated through doping with organic additives like anionic, nonionic or cationic surfactants. The organic additives are showing a crucial role in the growth process of metal oxide nanocrystals and hence can beused to control the morphology. These organic additives act also as impurities that would significantly change the conductivity of the electrodes. However, no organic compounds dependence was observed to modify the crystallographic structure. The findings in this thesis indicate the importance of the use of controlled nanostructures morphology for developing efficient functional materials.
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Ren, Yundong. « Specially Shaped Optical Fiber Probes : Understanding and Their Applications in Integrated Photonics, Sensing, and Microfluidics ». Digital WPI, 2019. https://digitalcommons.wpi.edu/etd-dissertations/569.
Texte intégralRésumé :
Thanks to their capability of transmitting light with low loss, optical fibers have found a wide range of applications in illumination, imaging, and telecommunication. However, since the light guided in a regular optical fiber is well confined in the core and effectively isolated from the environment, the fiber does not allow the interactions between the light and matters around it, which are critical for many sensing and actuation applications. Specially shaped optical fibers endow the guided light in optical fibers with the capability of interacting with the environment by modifying part of the fiber into a special shape, while still preserving the regular fiber’s benefit of low-loss light delivering. However, the existing specially shaped fibers have the following limitations: 1) limited light coupling efficiency between the regular optical fiber and the specially shaped optical fiber, 2) lack special shape designs that can facilitate the light-matter interactions, 3) inadequate material selections for different applications, 4) the existing fabrication setups for the specially shaped fibers have poor accessibility, repeatability, and controllability. The overall goal of this dissertation is to further the fundamental understanding of specially shaped fibers and to develop novel specially shaped fibers for different applications. In addition, the final part of this dissertation work proposed a microfluidic platform that can potentially improve the light-matter interactions of the specially shaped fibers in fluidic environments. The contributions of this dissertation work are summarized as follows: 1) An enhanced fiber tapering system for highly repeatable adiabatic tapered fiber fabrications. An enhanced fiber tapering system based on a novel heat source and an innovative monitoring method have been developed. The novel heat source is a low-cost ceramic housed electric furnace (CHEF). The innovative monitoring method is based on the frequency-domain optical transmission signal from the fiber that is being tapered. The enhanced fiber tapering system can allow highly repeatable fabrication of adiabatically tapered fibers. 2) A lossy mode resonance (LMR) sensor enabled by SnO2 coating on a novel specially shaped fiber design has been developed. The developed LMR sensor has a D-shape fiber tip with SnO2 coating. It has the capability of relative humidity and moisture sensing. The fiber-tip form factor can allow the sensor to be used like a probe and be inserted into/removed from a tight space. 3) Specially shaped tapered fibers with novel designs have been developed for integrated photonic and microfluidic applications. Two novel specially tapered fibers, the tapered fiber loop and the tapered fiber helix have been developed. The tapered fiber loop developed in this work has two superiority that differentiated itself from previous works: a) the mechanical stability of the tapered fiber loop in this work is significantly better. b) the tapered fiber loops in this work can achieve a diameter as small as 15 ?m while still have a high intrinsic optical quality factor of 32,500. The tapered fiber helix developed in this work has a 3D structure that allows it to efficiently deliver light to locations out of the plane defined by its two regular fiber arms. Applications of the tapered fiber helices in both integrated photonic device characterizations and microparticle manipulations have been demonstrated. 4) Developed an acrylic-tape hybrid microfluidic platform that can allow function reconfiguration and optical fiber integration. A low-cost, versatile microfluidic platform based on reconfigurable acrylic-tape hybrid microfluidic devices has been developed. To the best of the author’s knowledge, this is the first time that the fabrication method of sealing the acrylic channel with a reconfigurable functional tape has been demonstrated. The tape-sealing method is compatible with specially shaped fiber integrations.
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TOSCHI, FRANCESCO. « Preparazione di materiali nanocompositi a base carbonio per applicazioni tecnologiche ». Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2009. http://hdl.handle.net/2108/983.
Texte intégralRésumé :
La sintesi e le applicazioni dei materiali nanocompositi sono di importanza strategica nel campo della scienza dei materiali. In questo lavoro di tesi sono stati sviluppati diverse tipologie di materiali nanocampositi: Resina epossidica/nanotubi di carbonio (CNT), Poli(3,4-etilendiossitiofene) polistirensulfonato (PEDOT:PSS)/CNT, metallo/CNT. Questi materiali sono stati caratterizzati con le seguenti tecniche: Microscopia elettronica a scansione (SEM), Microscopia a forza atomica (AFM), microscopia acustica a forza atomica (AFAM), spettroscopia Raman e tecniche elettroanalitiche. La caratterizzazione funzionale è stata condotta testando i materiali in differenti applicazioni: Sensori resistivi, sensori di tipo nano-bilancia al quarzo e gestione del calore. I risultati sperimentali sono riportati nel lavoro di tesi.The synthesis and applications of nanocomposites are an important and strategical field of nanomaterial science. In this work has been developed several kind of nanocomposit materials, in particular: Epoxy resins and carbon nanotubes (CNT), Poly(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS) and CNT, metal and CNT. This material has been characterized by means of: scanning electron microscopy (SEM), Atomic force miscroscpy (AFM), acoustic atomic force microscopy (AFAM), Raman spectroscopy and Electroanalitical techniques. The developed nanocomposite material has been tested by means different kind of application: Resistive sensors, quartz nano-balance and thermal management. The results are reported in the thesis work.
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Nguyen, Van-Nghi. « Principes alternatifs pour la détection de masse ultime via la dynamique non linéaire de capteurs résonants M/NEMS ». Thesis, Lyon, INSA, 2013. http://www.theses.fr/2013ISAL0160/document.
Texte intégralRésumé :
Les capteurs résonants de type M/NEMS sont largement utilisés dans l’environnement biologique pour la mesure de masse de biomolécules en raison de leur grande précision combinée à une taille réduite. Classiquement, la détection et la quantification se basent sur le décalage fréquentiel induit par la masse ajoutée. Toutefois, ce décalage devient très faible et difficile à distinguer du bruit de mesure lorsque les masses considérées sont très petites. Il est théoriquement possible de gagner encore un ou plusieurs ordres de grandeur en résolution avec ces méthodes fréquentielles en diminuant encore les tailles et/ou en augmentant le rapport signal sur bruit, c’est-à-dire en actionnant de manière plus importante les résonateurs. Mais, dans ces conditions, les nanorésonateurs ont un comportement très fortement non-linéaire, source d’instabilités et de mixage de bruit basses et hautes fréquences susceptibles de dégrader la fiabilité et la précision des mesures. C’est pourquoi cette thèse a pour objectif de définir des principes de détection alternatifs basés sur l’exploitation des phénomènes non-linéaires, tels que les comportements hystérétiques et les bifurcations des courbes de réponse en fréquence. Pour cela, un modèle réduit de micro/nano-poutre résonante avec actionnement électrostatique est considéré. Les résultats numériques montrent que les brusques sauts d’amplitude à proximité des points de bifurcation permettent la détection de masses très faibles. Contrairement à la détection fréquentielle, ces sauts sont d’autant plus grands que la masse additionnelle est petite, ce qui rend cette technique particulièrement intéressante. De plus, le seuil de détection peut être ajusté avec la valeur de la fréquence de fonctionnement. Un mécanisme de réinitialisation est toutefois indispensable pour rendre la détection à nouveau possible après un saut d’amplitude. Afin d’automatiser la réinitialisation et ainsi permettre la détection en temps réel, un concept totalement innovant de détection de masse par balayage en fréquence des cycles d’hystérésis est proposé, qui permet de détecter, quantifier et localiser la masse ajoutée sur la poutre résonante. La mise en réseau de plusieurs poutres résonantes est également traitée et constitue un premier pas vers la mise en oeuvre de réseaux de milliers de capteurs. Pour cela, des architectures efficaces sont proposées et les modèles numériques sont adaptés en conséquence. Sur des configurations symétriques, l’exploitation des bifurcations de type brisure de symétrie permet là-encore d’améliorer la détection de masseResonant M/NEMS mass sensors are widely used in biological environment for measuring the mass of biomolecules due to their high accuracy combined with a reduced size. Usually, the detection and the quantification are based on the frequency shift induced by an added mass. However, this shift becomes very small and difficult to distinguish from the noise of measurement as the considered masses are tiny. It is theoretically possible to increase further one or several orders of magnitude in resolution with these frequency methods by further reducing size and/or by increasing the signal-to-noise ratio, that is to say by operating more importantly the resonators. But in these conditions, the nanoresonators have a strongly nonlinear behavior, a source of instability and noise mix of low and high frequencies likely to degrade the reliability and the accuracy of measurements. Therefore, the thesis’s objective is to define alternative principles of detection based on exploiting the nonlinear phenomena, such as the hysteretic behavior and the bifurcations of frequency-response curves. To this end, a reduced model of resonant micro/nano-beam with electrostatic actuation is considered. The numerical results show that the sudden jumps in amplitude close to bifurcation points allow the detection of very small masses. Unlike the frequency detection, the smaller the added mass, the larger the increase of the jump, which makes this technique particularly interesting. In addition, the detection threshold can be adjusted with the value of the operating frequency. However, a mechanism of reinitialization is mandatory to make the detection possible again after a jump in amplitude. In order to automate the reinitialization and allow the detection in real-time, a completely innovative concept of mass detection by the frequency sweep of the hysteretic cycles is proposed to detect, quantify and locate the added mass on the resonant beam. An array of several resonant beams is also considered and constitutes a first step toward the implementation of arrays of thousands of sensors. Efficient architectures are proposed for this purpose and the numerical models are adapted accordingly. On symmetric configurations, exploiting the bifurcations of symmetry-breaking type allows here again to improve the mass detection
27
Peyrot, Tom. « Dipole dipole interactions in dense alkali vapors confined in nano-scale cells ». Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLO012/document.
Texte intégralRésumé :
Les vapeurs atomiques confinées dans des cellules nanométriques constituent une plateforme intéressante pour la réalisation de senseurs atomiques. Dans cette thèse, nous étudions l’interaction entre la lumière et un ensemble d’atomes d’alcalins dans une telle cellule. Nous nous concentrons sur les phénomènes qui pourraient modifier la réponse optique du système et ainsi affecter la sensibilité du senseur. Premièrement, nous étudions la réponse non locale à la lumière induite par le mouvement des atomes dans la vapeur thermique. Quand la distance de relaxation des atomes excède la taille de la cellule, la réponse optique dépend de la taille du système. En transmission, nous avons montré que cela entraine une modification des propriétés de la vapeur avec une période égale à la longueur d’onde de la transition optique. Nous avons ensuite montré que lorsque la densité augmente, la réponse redevient locale. De plus, dans ce régime dense, l’interaction dipôle-dipôle résonnante engendre des déplacements de fréquences collectifs pour des ensembles sub-longueur d’onde. Nous avons démontré que ces shifts sont induits par la cavité formée par la cellule, clarifiant ainsi un débat de plus de 40 ans. Pour ce faire, nous avons développé un modèle pour extraire les effets de la densité déconvolués de ceux de la cavité. Proche des surfaces, la réponse optique des atomes est aussi impactée par l’interaction de van der Waals. Nous avons introduit une nouvelle méthode pour extraire avec précision la force de cette interaction. Nous avons également construit une nouvelle génération de nano-cellules super-polies en verre et enfin comparé les propriétés spectrales en transmission et spectroscopie hors d’axeAlkali vapors confined in nano-scale cells are promising tools for future integrated atom-based sensor. In this thesis, we investigate the interaction between light and an ensemble of atoms confined in a nano-geometry. We focus on the different processes that can modify the optical response of the atomic ensemble and possibly affect the sensitivity of a sensor based on that technology. First, we study the non-local response of atoms to a light excitation due the atomic motion in thermal vapors. When the distance over which the atoms relaxes is larger than the size of the cell, the optical response depends on the size of the system. We have observed that for transmission spectroscopy, this leads to a periodic modification of the optical response with a period equal to the wavelength of the optical transition. Subsequently we showed that when the density of atom increases, the atomic response becomes local again. In this dense regime, the resonant dipole-dipole interaction in a sub-wavelength geometry leads to collective frequency shifts of the spectral lines. We demonstrate that these shifts were induced by the cavity formed by the cell walls, hence clarifying a long-standing issue. We developed a model to extract the density shifts deconvolved from the cavity effects. Close to a surface, the optical response is also affected by the van der Waals atom-surface interaction. We introduced a new method to extract precisely the strength of this interaction. We also developed a new generation of super-polished glass nano-cells and we presented promising spectroscopic signals. Finally, using these cells, we have compared transmission and off-axis spectroscopic techniques
28
Lombardo, David. « Design and Fabrication of Suspended Waveguides With Photonic Grating Structures ». University of Dayton / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1591796311145344.
Texte intégral
29
Dinh, Nghia Trong. « Direkter Drucksensor unter Verwendung von Kohlenstoffnanoröhren-Nanokompositen ». Doctoral thesis, Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-203785.
Texte intégralRésumé :
Im Gegensatz zu herkömmlichen Dehnungsmessstreifen können Carbon nanotube (CNT)-basierte Komposite zusätzlich eine ausgeprägte Druck-abhängigkeit des Widerstandes aufweisen. Deshalb können Drucksensoren aus CNT-Nanokomposite ohne den Einsatz von Verformungskörpern wie z. B. Biegebalken aufgebaut werden. Die möglichen Anwendungsgebiete für diese direkt messenden Sensoren wurden in der vorliegenden Arbeit bei drei industriellen Anwendungen wie z. B. bei Robotergreifarmen gezeigt. Die Zielstellung dieser Arbeit ist die Entwicklung und Charakterisierung eines neuartigen Sensors aus CNT-Nanokomposite. Unter Verwendung von Multi-walled carbon nanotube (MWCNT)-Epoxidharz und interdigitalen Elektroden soll der Sensor auf wenigen Quadratzentimetern Drücke im Megapascal-Bereich und somit Kräfte im Kilonewton-Bereich messen können. Durch die Auswahl geeigneter Werkstoffe und die Modellierung mit der Finite Element Methode wurde der Sensorentwurf durchgeführt sowie der Messbereich abgeschätzt. Die Herstellung der MWCNT-Epoxidharz-Dispersion erfolgte durch mechanische Mischverfahren. Anschließend wurden aus der Dispersion druckempfindliche Schichten mit der Schablonendrucktechnik hergestellt. Dabei wurden die Herstellungs-parameter und besonders der Füllstoffgehalt der MWCNTs variiert, um deren Einflüsse auf das mechanische, thermische und elektrische Verhalten zu untersuchen. Die Charakterisierung der mechanischen Kenngrößen erfolgte mit Zugversuchen und dynamisch-mechanischer Analyse. In den Untersuchungen zeigen die MWCNT-Komposite eine signifikante Steigerung der Zugfestigkeit und eine Erhöhung der Glasübergangstemperatur gegenüber reinem Epoxidharz. Die Abhängigkeiten der Druckempfindlichkeit und der Temperaturempfindlichkeit vom Füllstoffgehalt wurden untersucht. Eine besonders hohe Druckempfindlichkeit, aber auch Temperaturempfind-lichkeit wurde bei Proben mit geringem Füllstoffgehalt (1 wt% und 1,25 wt%) festgestellt. Es ist also wichtig, die richtige Materialkombination für diese Art Sensor zu finden. Die realisierten Sensoren liefern zuverlässige Antwortsignale bei wiederholten Belastungen bis zu einer Belastung von 20 MPa (entspricht 2 kN). Zusätzlich wurde der Temperatureinfluss in einem Bereich von −20 °C bis 50 °C durch eine Wheatstonesche Brückenschaltung kompensiert. Die vorliegende Arbeit zeigt, dass eine zuverlässige Druckmessung mit einer Temperaturmessabweichung von 0,214 MPa/10 K gewährleistet werden kannIn contrast to conventional metallic strain gauges, carbon nanotube (CNT) composites have an additional pressure sensitivity. Therefore, deformation elements such as bending beam is not needed by using pressure sensors, which are based on CNT nanocomposite. The possible areas of application for these pressure direct measured sensors were showed in three industrial application such as robot gripper. The focus of this work is the development and characterization of a new sensor manufactured from CNT nanocomposite. By using multi-walled carbon nanotube (MWCNT) epoxy and interdigital electrodes the sensor, which has a dimension of few square centimetre, should measure a pressure in mega Pascal range and hence a force in kilo newton range. By the selection of suitable materials and the modelling using finite element method, the sensor design as well as the measurement range were carried out. The MWCNT epoxy dispersion is manufactured by using a mechanical mixing process. Subsequent, the dispersion is used to fabricate pressure sensitive layers by stencil printing methods. Thereby, the fabrication parameters and especially the filler content of the MWCNTs were varied for the mechanical, thermal and electrical investigation. The characterization of the mechanical characteristic values were carried out by using tensile test and dynamic mechanical analysis. The results show a significant increasing of the tensile strength and glass transition temperature in comparison to neat epoxy. Additionally, the influence of the filler content to the pressure and thermal sensitivity were investigated. A highly pressure sensitivity but also a highly thermal sensitivity are obtained for samples with lower filler contents (1 wt% and 1.25 wt%). Therefore, a suitable material combination has to be chosen. The fabricated sensors show reliable response signals by repeated excitations up to 20 MPa (meets to 2 KN). Moreover, the temperature influence ranged from -20 °C to 50 °C was compensated with a Wheatstone bridge. This work demonstrate a direct pressure sensitive sensor with reliable response signals by a thermal deviation of 0.214 MPa/10K
30
Henry, James Edward. « Development of nano-scale and biomimetic surfaces for biomedical applications ». Texas A&M University, 2005. http://hdl.handle.net/1969.1/4395.
Texte intégralRésumé :
The work described in this dissertation details the development of a biomimetic
materials for use in sensors and therapeutics, based on new advances in material science.
The sensors developed herein target neurodegenerative diseases. Two of the diseases,
the transmissible spongiform encephalopathies (TSEs) and AlzheimerâÂÂs disease (AD),
are diseases associated with the abnormal folding of a protein, thus detecting the disease
is dependent upon developing structure specific sensor technologies. Both sensors
developed in this work take advantage of the unique optical properties associated with
nanoscale metal particles, however they use different types of spectroscopies for optical
detection of the presence of the disease associated abnormal protein, and different types
of recognition elements that bring the disease associated proteins close to the nanoscale
metal particles. In the case of TSEs, the recognition element was a commercially
available antibody. In the case of AD, the recognition element was a molecular scale
self-assembled surface. A therapeutic for AD was developed based on the molecular
scale materials developed for the AD biosensor. Mathematical models were developed that facilitated the rational design of the biosensors described in this work that could also
be used in future biosensor development.
31
Chan, Leon Cong Zhi. « Miniaturisation of pH holographic sensors for nano-bioreactors ». Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/268167.
Texte intégralRésumé :
Monitoring and controlling pH is of utmost importance in bioprocessing as it directly affects product yield and quality. Multiplexed experiments can be performed in nanobioreactors for optimisation of yield and cell heterogeneity in a relatively quick and inexpensive manner. In this thesis, a pH holographic sensor (holosensor) is miniaturised to 3.11 nL in volume and integrated into a PDMS-glass microfluidic chip for monitoring the growth of Lactobacillus casei Shirota. Although other established methods for monitoring cell cultures can be utilised, miniaturised holosensors enable real-time and non-consumptive monitoring of the bacterial cell culture growth medium. The 2-hydroxyethylmethacrylate (HEMA)-co-2-(trifluoromethyl) propenoic acid (TFMPA) holosensor was fabricated using an adapted technique from photolithography, coupled with the use of a polymerisation inhibitor to control the gel polymerisation with diameters not exceeding a standard deviation of 0.067. The hologram brightness was optimised to 1.05 ms integration time with 36X magnification using a low power (0.290 mW) 532 nm green continuous wave (CW) laser with a devised beam-offset technique. The holosensor was characterised with ionic strength balanced (9.50 mS/cm) McIIvaine pH buffers and a calibration curve plotted together with measured ionic strength, optical density at 600 nm (OD600) and pH. Correspondingly, RGB-xyY transformed values were plotted in the CIE 1931 chromaticity diagram. Later, a miniaturised 0.4φ HEMA-co-TFMPA holosensor and array was also demonstrated. Together with the 3.0φ holosensor, an accuracy parameter for the 0.4φ spot and array holosensors were calculated to be 99.08%, 99.38% and 97.77% respectively. Further work involved studying the issues associated with fabricating gels with unusually flat gel profiles. Other preliminary results suggested the alternative of utilising polymers as a holosensor substrate, together with a dye-free method for hologram fabrication, outlined the prospective possibility of a miniaturised holosensor integrated into a polymer microfluidic chip with the flexibility of hologram colour customisation for cell culture monitoring.
32
Zhang, Da. « On the Low Frequency Noise in Ion Sensing ». Doctoral thesis, Uppsala universitet, Fasta tillståndets elektronik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-320544.
Texte intégralRésumé :
Ion sensing represents a grand research challenge. It finds a vast variety of applications in, e.g., gas sensing for domestic gases and ion detection in electrolytes for chemical-biological-medical monitoring. Semiconductor genome sequencing exemplifies a revolutionary application of the latter. For such sensing applications, the signal mostly spans in the low frequency regime. Therefore, low-frequency noise (LFN) present in the same frequency domain places a limit on the minimum detectable variation of the sensing signal and constitutes a major research and development objective of ion sensing devices. This thesis focuses on understanding LFN in ion sensing based on both experimental and theoretical studies. The thesis starts with demonstrating a novel device concept, i.e., ion-gated bipolar amplifier (IGBA), aiming at boosting the signal for mitigating the interference by external noise. An IGBA device consists of a modified ion-sensitive field-effect transistors (ISFET) intimately integrated with a bipolar junction transistor as the internal current amplifier with an achieved internal amplification of 70. The efficacy of IGBA in suppressing the external interference is clearly demonstrated by comparing its noise performance to that of the ISFET counterpart. Among the various noise sources of an ISFET, the solid/liquid interfacial noise is poorly studied. A differential microelectrode cell is developed for characterizing this noise component by employing potentiometry and electrochemical impedance spectroscopy. With the cell, the measured noise of the TiN/electrolyte interface is found to be of thermal nature. The interfacial noise is further found to be comparable or larger than that of the state-of-the-art MOSFETs. Therefore, its influence cannot be overlooked for design of future ion sensors. To understand the solid/liquid interfacial noise, an electrochemical impedance model is developed based on the dynamic site-binding reactions of surface hydrogen ions with surface OH groups. The model incorporates both thermodynamic and kinetic properties of the binding reactions. By considering the distributed nature of the reaction energy barriers, the model can interpret the interfacial impedance with a constant-phase-element behavior. Since the model directly correlates the interfacial noise to the properties of the sensing surface, the dependencies of noise on the reaction rate constants and binding site density are systematically investigated.
33
Stedt, Viktor. « Wearable EMG sensor och kraftmätning med trådtöjningsgivare ». Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-277741.
Texte intégralRésumé :
Vid träning av baksida lår kan det vara svårt att förstå hur muskeln aktiveras. Genom att visualisera de myoelektriska signalerna från biceps femoris och semimembranosus till den som tränar kan personen få en bättre mind-muscle connection. I examensarbetet har två teoretiska EMG sensorer skapats och simulerats, kod har skrivits för att filtrera fyra EMG signaler samt överföra dessa över BLE, kraftsensorer är kopplade och kod är skriven för att avgöra den kraftutveckling som sker i en kontraktion av baksida lår. EMG sensorerna har jämförts med SparkFuns MyoWear muskelsensor, OpenBCI Cyton board och BioNomadix BN-EMG2-T. Båda de teoretiska lösningarna anses likvärdiga med ett billigare alternativ till Cryton Board, en flerkanalig lösning till MyoWear, BN-EMG2-T är för dyr att realistiskt implementeras till examensarbetets syfte. Simuleringarna visar att kretsarna behandlar signalen enligt tänkt sätt men det gick inte att bygga en prototyp då en pandemi har begränsat KTH:s verksamhetOne difficulty when training hamstrings is the understanding of how the muscle is activated. Through visualization of the myoelectrical signals from biceps femoris and semimembranosus to the exerciser, a better mind-muscle connection can be achieved. In this bachelor thesis, two theoretical EMG sensors were created and simulated, code to filter four EMG signals and transmit them through BLE was written, also a way to calculate how much force is applied in a hamstring curl was constructed. Both EMG sensors have been compared against SparkFuns MyoWear muscle sensor, OpenBCI Cyton Board and BioNOmadix BN-EMG2-T. The theoretical EMG sensors are interconvertible to a cheaper Cyton Board, a multichannel alternative to MyoWear, the BN-EMG2-T is too expensive to be a realistic alternative for this bachelor thesis attended purpose. Simulations show that the EMG sensors behave as intended but because of a pandemic, a prototype could not be created.
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SINGH, ARUN. « Design of Current Sensors to measure small current signals of pico-amperes to nano-amperes in magnitude ». University of Cincinnati / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1205161608.
Texte intégral
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Yan, Jun. « Metrology and Characterization of Impurity Transport During Cleaning of Micro and Nano Structures ». Diss., The University of Arizona, 2006. http://hdl.handle.net/10150/195231.
Texte intégralRésumé :
A major challenge in the manufacturing of micro and nano devices is the cleaning, rinsing, and drying of very small structures. Without a technology for in situ and real-time monitoring and controlling, the rinse processes that account for a significant fraction of the total processing steps use a large amount of water and energy perhaps unnecessarily. This "blind" processing approach leads to waste that can have significant economic and environmental impacts. An electrochemical residue sensor (ECRS) has been developed and is aimed at in situ and real-time measurement of residual contamination inside the micro and nano structures. Using this technology, the mechanisms and bottlenecks of cleaning, rinsing, and drying can be investigated and the processes can be monitored and controlled.An equivalent circuit model was developed to assist the design of the sensor; its validity was proved by the first prototype. The simulation results and the experimental data predicted a good sensitivity in a wide range of operational frequency. To use the sensor in a practical rinse tank setup, the sensor-on-wafer prototype was designed and fabricated. Both the fab-scale and the lab-scale tests were performed and results illustrated many successes. The sensor is the first and the only available technology that provides the in situ and real-time cleanness information in the microstructures during the rinse processes. The sensor results distinguished four different types of rinse processes and showed high sensitivity to the ionic concentration change in the microstructures. The impacts of cleaning and rinsing parameters such as flow rate, temperature, cleaning solution concentrations, and process time on the sulfuric acid rinsing efficiency were investigated by using the sensor. The investigation discovered that sulfuric acid rinsing is a two-stage process: a flow-control stage and a desorption-control stage. A comprehensive rinse model was developed to correlate the transport process and the trench impedance that is the sensor's signal. This model combined with the experimental data proved that increasing flow rate in the overflow rinse has a low efficiency for the rinse processes controlled by the surface reactions. The model, for the first time, shows the dynamics of the charging of the silicon dioxide surface and the dynamics of the potential build-up in the solution. It also discovered that the cation rinsing is a challenge if the cation adsorbs on or reacts with the surface.
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Luongo, Kevin. « Palladium Doped Nano Porous Silicon to Enhance Hydrogen Sensing ». Scholar Commons, 2006. http://scholarcommons.usf.edu/etd/3896.
Texte intégralRésumé :
A mass manufacturable impedance based, palladium doped porous silicon sensor, was fabricated for hydrogen detection. The sensor was built using electrochemical etching to produce mesoporous silicon. Four nanometers of palladium was defused directly into the porous silicon and another four nanometers of Pd was deposited on the defused surface to enhance sensing. The sensor was tested in a sealed chamber in which the impedance was measured while hydrogen in nitrogen was ranged from 0-2 percent. Unlike conventional hydrogen sensors this sensor responded at room temperature to changes in hydrogen concentration. The electrical impedance response due to adsorption and desorption of hydrogen reacted relatively quickly due to the nanoparticle nature of palladium diffusion in and Pd evaporation on porous silicon.
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PARGOLETTI, ELEONORA. « THREE-DIMENSIONAL NANO-HETEROJUNCTIONS FOR PHOTO- AND CHEMICAL SENSING ». Doctoral thesis, Università degli Studi di Milano, 2020. http://hdl.handle.net/2434/703276.
Texte intégralRésumé :
La percezione sensoriale dell'ambiente circostante è strettamente correlata allo sviluppo della vita animale e umana; in particolare, il rilevamento di gas è un'esperienza sensoriale complessa che influenza le nostre decisioni e azioni. Tuttavia, il sistema olfattivo umano è limitato ad una rilevazione qualitativa di pochi gas. Inoltre, lo sviluppo industriale negli ultimi decenni, insieme al drastico miglioramento della qualità della vita e della mobilità, ha aumentato le esigenze di rilevazione quantitativa di diversi analiti. L'analisi di miscele di gas online è fondamentale in molti campi di ricerca e, al giorno d'oggi, l'attenzione è rivolta al rilevamento analitico a fini diagnostici. In particolare, il crescente sviluppo di dispositivi innovativi ha portato all’ottenimento di nuovi sensori miniaturizzati, capaci di sentire basse concentrazioni di differenti biomarker, con veloci tempi di risposta a temperatura ambiente. Nello specifico, i principali parametri da considerare per la fabbricazione di dispositivi ottimali sono i seguenti: sensibilità, basse temperature di lavoro, tempi di risposta/recupero e selettività. A tal proposito, i nanomateriali a base di carbonio, nonostante mostrino numerose proprietà come una bassa resistività e buona resistenza meccanica, non possiedono buone capacità di rilevazione e trasduzione nei confronti di molecole o fotoni. D'altra parte, i chemoresistori a base di Semiconduttori di Ossidi Metallici (MOS) nonostante siano ampiamente utilizzati, presentano ancora numerosi inconvenienti, in particolare legati alle alte temperature operative e alla scarsa selettività. Lo scopo del presente progetto di dottorato è, quindi, la sintesi di nanostrutture tridimensionali, caratterizzate da eterogiunzioni perfettamente integrate di Ossido di Grafene (GO) e MOS (di tipo n) per il rilevamento a bassa temperatura e sotto irraggiamento UV di Composti Organici Volatili (VOC come ad esempio etanolo, acetone, toluene ed etilbenzene). Nello specifico, sono stati investigati diversi ossidi di metalli di transizione (ZnO, SnO2, WO3, TiO2 o una soluzione solida di SnO2-TiO2) al fine di preparare film porosi e micrometrici (alcuni micron) aventi promettenti proprietà chemoresistive. Inoltre, mentre il semiconduttore a base ossidica è di solito responsabile del rilevamento di gas ad alte temperature, l’ossido di grafene svolge il ruolo fondamentale di migliorare la sensibilità e soprattutto la detection a bassa temperatura, anche grazie alla presenza della luce UV. I materiali così ottenuti, avendo un'eccellente risposta alle radiazioni ultraviolette, risultano essere anche ottimi fotorilevatori. Successivamente, è stato studiato l'effetto della quantità di GO sulle performance dei semiconduttori, specialmente in presenza di una matrice di ZnO o di SnO2. Nel caso del biossido di stagno, infatti, un alto contenuto di GO consente di ottenere sia una risposta a temperatura ambiente, che una maggiore selettività verso molecole più grandi e non polari, come l'etilbenzene. Al contrario, basse quantità di GO aumentano la selettività verso molecole polari come l’etanolo, aprendo di fatto nuovi orizzonti alla sintesi e all’ingegnerizzazione di nuovi materiali, in grado di rilevare concentrazioni di VOC dell’ordine dei ppb. In aggiunta, la matrice di SnO2 porta a performance migliori rispetto a quelle ottenute con l’ossido di zinco, sia in termini di intensità del segnale che di sensibilità. Quindi, studi preliminari, volti a migliorare ulteriormente la selettività, sono stati condotti preparando composti ternari formati da una soluzione solida SnO2-TiO2 e GO: in questo caso è stata osservata una maggiore selettività per le molecole grandi e non polari, come il toluene. Inoltre, è noto che le proprietà chimico-fisiche dei chemoresistori influenzano fortemente le loro caratteristiche di detection. Quindi, parallelamente al precedente studio, l’attenzione è stata focalizzata sulla sintesi ad hoc di ossido di tungsteno adottando diversi precursori e agenti strutturanti. In particolare, si è osservato che il diametro dei cristalliti, l’area superficiale e il volume/forma dei pori sono i principali parametri alla base delle performance sensoristiche in termini di intensità del segnale e tempi di risposta/recupero. Allo stesso tempo, calcoli computazionali e misurazioni XANES in situ presso il sincrotrone (ESRF) di Grenoble sono stati effettuati al fine di confermare/ipotizzare il meccanismo di sensing. Particolare attenzione è stata, poi, rivolta ai sistemi misti MOS-GO, dove la formazione di giunzioni p (GO) – n (MOS) amplifica e migliora il segnale. In conclusione, i risultati ottenuti con questo progetto di dottorato possono essere considerati delle linee guida per l’ingegnerizzazione di nuovi dispositivi ibridi a base di materiali carboniosi e ossidi di metallo, per applicazioni che vanno dall'optoelettronica al campo sensoristico e a quello dell'elettrocatalisi.The sensorial perception of the surroundings is critically related to the development of animal and human life. Human smell, or more generally, gas detection is a complex experience that subtly influences our decisions and actions. However, the human olfactory system is limited to a qualitative detection of few gases. Besides, the industrial development in the last decades, together with the drastic improvement of life quality and mobility, has increased the needs for quantitative detection of different analytes. Online analysis of gas mixtures is fundamental in many research fields and, nowadays, the attention has been particularly focused on their analytical detection for diagnostic purposes. Specifically, the rapid development of smart wearable electronic devices is driving the engineering of novel miniaturized sensing materials that can rapidly respond to very small changes in the concentration of biomarkers at room temperature. In particular, sensitivity, low operating temperature, response/recovery times and selectivity are the main parameters to consider in order to prepare optimal sensing devices. Hence, carbon-based nanomaterials offer numerous attractive properties such as low resistivity, good mechanical robustness and integration potential, but lack a strong detection for the measurement of chemical molecules or photons. On the other hand, chemiresistors based on Metal Oxide Semiconductors (MOS) have been widely exploited, even if they still show several drawbacks especially connected to the high operating temperatures and scarce selectivity. Thus, the focus of the present PhD research project was the synthesis of three-dimensional nanostructured architectures comprising of optimally integrated Graphene Oxide (GO) – n-type MOS heterojunctions for the photo-assisted low temperature sensing of Volatile Organic Compounds (VOCs, i.e. ethanol, acetone, toluene and ethylbenzene). Specifically, different transition metal oxides (ZnO, SnO2, WO3, TiO2 or a solid solution of SnO2-TiO2) have been deeply investigated in order to prepare few micrometers porous films with promising chemoresistive properties. Moreover, while MOS is usually responsible for the gas detection at high operating temperatures, the addition of graphene oxide plays the pivotal role of enhancing the sensitivity, especially at room temperature, by exploiting the UV light. These layouts have been also demonstrated to provide excellent response to UV irradiations showcasing their applicability as visible-blind photodetectors. Furthermore, the effect of low and high GO content has been evidenced, emphasizing the different result when combined to ZnO or SnO2 matrix. Notably, in the case of tin dioxide, great GO content allows to obtain both a response at RT and an increased selectivity towards bigger and non-polar molecules, as ethylbenzene. Whereas, small amounts of GO lead to a higher selectivity to polar molecules as ethanol, opening up new horizons for the preparation of well-performing low ppb sensing materials. In addition, SnO2 matrix seems to have higher sensing features than zin oxide material, in terms of either signal intensity or sensitivity. Therefore, preliminary studies, aimed at further improving the selectivity, were carried out by fabricating ternary compounds composed by SnO2-TiO2 solid solution and GO: a smooth selectivity towards large and non-polar molecules (such as toluene) was noticed. Parallelly, the physico-chemical properties of chemoresistors strongly influence their sensing behavior: adopting WO3 as a case study, the synthetic strategy was modified by finely tuning the tungsten precursors and the structure directing agents. Notably, it was noticed that the crystallite diameters, the surface area and the pores volume/shape drastically affect the sensing performances, in terms of either the signal intensity or the response/recovery times. Concurrently, a computational study and in situ XANES measurements (at the European Synchrotron Radiation Facility, ESRF in Grenoble) on acetone detection by tungsten trioxide were conducted to further corroborate the sensing mechanism. Finally, an extension of this mechanism to MOS-GO composites was hypothesized in which the formation of p(GO) – n(MOS) junctions clearly enhances the sensing behavior. In conclusion, we believe that the findings obtained with this doctoral project can provide guidelines for the future engineering of hybrid carbon-metal oxide devices for application extending from optoelectronics to chemical sensing and electrocatalysis.
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Shenashen, M. A., et S. A. El-Safty. « Visual Detection and Recovery of Mercury in Water and Blood Samples Using Nano-membrane Tubular Architectures ». Thesis, Sumy State University, 2015. http://essuir.sumdu.edu.ua/handle/123456789/42664.
Texte intégralRésumé :
Engineered control over one-dimensional (1D) mesoporous silica nanotubes (NTs) inside anodic alumina membranes (AAMs) has led to various methods for detecting, visualizing, adsorbing, filtering, and recovering ultra-trace concentrations of toxic metal ions, such as Hg2+ and Pb2+, in water and blood. These often “one-pot” screening methods offer advantages over conventional methods in that they do not need sophisticated instruments or laborious sample preparation. This mesoscopic membrane sensor for the nakedeye detection micro-object have large surface area-to-volume ratios and uniformly shaped pores in threedimensional nanoscale gyroidal structures and its active sites consist of heteroatoms arranged around uniformly shaped pores in three-dimensional (3D) nanoscale gyroidal mesostructures densely coated with the
chelating ligand so it permits ultra-fast, specific, pH-dependent visualization and removal of toxic metals at low concentrations from aqueous media, including drinking water and a suspension of red blood cells by means of a colorimetric signal visible to the naked eye, as well as by means of UV–vis reflectance spectroscopy.
Removal of target ions from biological fluids was assessed by means of flow cytometric analysis. Our results demonstrate the potential for our membrane sensors to be used for preventing the health risks associated with exposure to toxic metal ions in the environment and blood.
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Santos, Figueroa Luis Enrique. « New approaches for the development of chromo-fluorogenic sensors for chemical species of biological, industrial and environmental interest ». Doctoral thesis, Universitat Politècnica de València, 2015. http://hdl.handle.net/10251/43216.
Texte intégralRésumé :
El presente proyecto de investigación está enfocado al desarrollo de sensores químicos fluoro-cromogénicos, para la detección y determinación de especies químicas de interés biológico, industrial y medioambiental de forma selectiva y con alta sensibilidad.
En forma general, se busca el diseñar nuevos sistemas sensores basados en compuestos (receptores) formados por dos unidades: una unidad coordinante que interacciona con el anión a determinar y una unidad generadora de señal que alerta del reconocimiento molecular efectuado.
Durante este estudio se están preparando diversas moléculas receptoras funcionalizandas con grupos modificadores de estructura para evaluar su influencia sobre las capacidades de detección y selectividad como receptores de especies específicas en diferentes condiciones y medios.
Las diferentes aproximaciones en prueba implican a su vez el diseño y síntesis molecular, así como el análisis de las diferentes señales ópticas producidas en el reconocimiento, con el fin de diseñar sistemas de alta eficacia y eficiencia, y con posibilidades reales de aplicación.Santos Figueroa, LE. (2014). New approaches for the development of chromo-fluorogenic sensors for chemical species of biological, industrial and environmental interest [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/43216
TESIS
Premiado
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shiao, keith, et 蕭澤宗. « Nano-electrochemistry CO gas sensor ». Thesis, 2006. http://ndltd.ncl.edu.tw/handle/89318892824935956658.
Texte intégralRésumé :
碩士國防大學中正理工學院
應用化學研究所
94
This research is regarding platinum-ruthenium alloy as and detecting catalysts, that will detect catalysts and add the deionized water to mix into the electrode thick liquid material . This experiment is divided into two stages: 1.The discussion of treatment before the catalyst, 2. Analysis of the behavior that the electrode is detected to the gas. Deal with some before the catalyst, by way of different mixing separately, add different dispersant and thickness of the dispersant as the parameter, analyse catalysts to disperse and stabilize the situation with Laser Light Scattering system Zeta Plus and Rheometry ; in addition, in the electrode on detecting analysing to the gas, probe into and analyse that detects the detecting and examining to carbon monoxide of electrode by making the law of electric potential. The experimental result shows , the platinum-ruthenium alloy electrode presents the linear relations to detecting the electric current and concentration of carbon monoxide. In addition, detecting electrodes under the circumstances that the optimum condition is made, the best initial time is 10 seconds, response time expires by 50 to 60 seconds, can obtain the best sensitivity of detecting and can be examined for the 4.14 μA/ppm and the minimum concentration of limit to 25 ppm .
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逄宜哲. « Research on Nano CMOS MEMS Gas Sensor ». Thesis, 2010. http://ndltd.ncl.edu.tw/handle/x63z9d.
Texte intégralRésumé :
碩士國立彰化師範大學
機電工程學系
98
Abstract This study proposes two different types of CO gas sensors, one of the ion sensor using field effect transistors (Ion Selective Field Effect Transistor, ISFET) to carry out carbon monoxide gas sensor manner, and its interface circuit technology and design combined with the sensing element structure, integrated gas sensor chip is made. Carbon monoxide sensors based on Si (Silicon) as substrate, P-type polysilicon (P-poly Silicon) when the micro-heater resistance, N-type poly (N-poly Silicon) When the etch stop layer, the N-type polysilicon, the re-heating a thin layer of oxide growth, the sensing material SnO2 was deposited onto the electrodes after sol-gel formation to detect the structure of CO gas. When the micro-heater temperature resistance to provide work, the number detected in the ISFET Telecommunications (Vs) at different CO concentrations in different variations. We use the TSMC 0.35μm CMOS 2P4M standard process and the production design process, after carbon monoxide sensors, ISFET amplifier circuit through the small amount of input and output voltages are different, but the actual measured results, as expected, did not significantly sensor signal, for sensing the gas from the electric sensor chip, the sensor out of the telecommunications insensitive and beating No. Although a large volume of design that we can try to clear the mechanism of the charge, the charge will reflect the volume after the measurement, the re- set to zero, in order to improve its telecommunications number of sensor in order to avoid signal saturation. III Another model for the resistance of carbon monoxide gas sensor, which is designed to honeycomb sensing electrode Finger type, using standard TSMC 2P4M 0.35um process of the metal layer Metal1 as Metal Mask, and to Metal4/Via34/Metal3/Via23/Metal2 level as a series of metal sensing electrode, and by P-type polysilicon (P-poly Silicon) when the micro-heater resistance 4.2kΩ, to provide heating power 120uW, the sensing material SnO2 was deposited onto the electrodes after sol-gel formation to detect CO gas, CO gas molecules when the sensor falls within the region, the adsorption on the sensor electrode, making electrode plate and the resistance value between electrodes changed, the corresponding measurements The sensitivity to the smallest resistor is 0.08%, while the CO concentration corresponding to the minimum limit of 4ppm the following. Keyword : Carbon monoxide、micro-heater、sol-gel、SnO2、ISFET.
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Shie, Wei-chen, et 謝瑋宸. « PAH/Nano mica and PDDA/Nano mica composites for low-humidity sensor application ». Thesis, 2010. http://ndltd.ncl.edu.tw/handle/16967756171057591210.
Texte intégralRésumé :
碩士中國文化大學
應用化學研究所
98
Layer-by-layer self-assembled mica and cationic polyelectrolyte (poly(allylamine hydrochloride)) (PAH) or poly(diallyldimethylammonium chloride) (PDDA) on a quartz-crystal microbalance (QCM) for low-humidity sensing applications. The surface characteristics of the thin films were studied for various assembly conditions of polycations type, polycations concentration and the number of layers. The thin films were characterized using QCM and by atomic force microscopy (AFM). The surface roughness and thickness of the mica/PDDA thin film both exceeded that of the mica/PAH thin film. The effects of the polycations type, polycations concentration and the number of layers on the low-humidity sensing properties (sensitivity) of the sensors were investigated. Additionally, other low-humidity sensing properties such as sensing linearity, response and recovery times and reproducibility were studied. The mica/PDDA multilayered thin film had the highest sensitivity (0.930 –Hz/ppmv at 42.9 ppmv) and linearity and a short response time (12 s at 92.2 ppmv).
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李彥琦. « Fabrication and Characterization of Nano-Air-bridge Sensor ». Thesis, 2009. http://ndltd.ncl.edu.tw/handle/26165355469004085940.
Texte intégralRésumé :
碩士國立彰化師範大學
物理學系
97
In this thesis, a fine process for fabricating nano-air-bridge junction has been developed. Through electrostatic trapping technique integrated in this air-bridge device, we were able to trap nano-particle into the junction. All the properties were characterized by current-voltage curve, first and second derivative of I-V curves measurements. A series of nano-air-bridge devices were fabricated by a bottom up process and the techniques involved are as follows : electron beam lithography, photolithography, reaction ion etching, wet etching, thermal evaporation, sputtering system, and scanning probe microscopy. The key to get different gap-size of nano-air-bridge is varying the thickness of mid-layer of SiO2. The top and bottom gold electrodes are 50 nm and 30 nm thick, respective, and the SiO2 layer is controlled within 5 nm to 15 nm. The cross area of nano-air-bridge is below 80 nm × 80 nm. In addition, nano-airbridge is also fabricated on the top of a 100 nm SiN membran for being inspected using transmission electron microscopy(TEM). Through four-terminal I-V measurement on Au-SiO2-Au, typical nonlinear I-V curves have been obtained. Furthermore, a photo-assisted exciting effect is also observed in this metal-insulator-metal (MIM) structure. This phenomenon may have been caused by the coupling surface plasmon on the both side of metal electrode. After removing SiO2 layer, the I-V curve indeed indicated a lower barrier height in Au-Air-Au junction. By dipping this junction in diluted CdSe solution and adopting with a electrostatic trapping (ET) technique, I-V curve measurement revealed that the nano-particle have been trapped into the gap successfully.
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Yu-Jen et 方昱仁. « Nano-Structured SnO2-Au Sensor for H2S Detection ». Thesis, 2009. http://ndltd.ncl.edu.tw/handle/05408106417322191125.
Texte intégralRésumé :
碩士中山醫學大學
口腔生物暨材料科學研究所
97
The purpose of this study use nanostructured SnO2/Au to develop a miniature hydrogen sulfide gas sensor. We used the sol-gel method to synthesis SnO2 which doped with and without Au nanoparticles. Moreover, this developed sensing material was dripped on interdigital electrode by spin-coating method. These semifinished material sensors were calcine at 400℃ to form a porous structure. Compare with pure and Au doped SnO2 sensitivity for hydrogen sulfide detection. In charactering of sensing thin film, X-ray diffraction were used to analyze the composition of SnO2/Au nanocomposites. SEM and TEM images were respectively used to observer the morphology and to quantify the particle size. The result showed that for hydrogen sulfide detection, there have maximum response in SnO2+1Au composites, and was able to detect low concentration was about 0.2 ppm at room temperature. The selectivity of sensors for 1ppm H2S have maximum response and all sensors exhibited low response to 20 ppm SO2, 50 ppm NH3, 1000 ppm CO2 and 20% O2. Then we detect 70% and 99.5% alcohol vapor, the result revealed lower influence with 99.5% alcohol vapor than 70% alcohol vapor. We also studied the effect of humidity (50%, 70% and 80% RH) to H2S detection. The result show influenced with humidity. However, in humid environment have influence of sensor detection, so we need to avoid this condition.
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Cheng-JingLai et 賴承敬. « Fabrication of Gas Sensor with Nano-Sphere Structures ». Thesis, 2013. http://ndltd.ncl.edu.tw/handle/90452349255515007504.
Texte intégralRésumé :
碩士國立成功大學
微電子工程研究所碩博士班
101
In this work, we present a series of AlGaN-based Schottky diode hydrogen-sensing devices. The nanospheres (nanoparticles) are used to make different nanostructure on the surface of sensing area. The key point is that the nanoscale (〈 100 nm) material provides a large specific surface area. Different nanostructures were fabricated by effectively coating the PS nanospheres (NS) and SiO2 nanoparticles (NPs). The structures were used to enhance the sensing performance. The hydrogen sensing and response characteristics of studied devices under different hydrogen concentrations are investigated in an air atmosphere. Firstly, a Pd/AlGaN (M-S) Schottky diode hydrogen sensor is fabricated and investigated. Due to wide bandgap and superior thermal stability, the studied AlGaN-based diode-type hydrogen sensor exhibits a higher detection sensitivity, a larger Schottky barrier height variations, and a wide temperature range. Secondly, the pyramid-like Pd structure on the Pd metal surface is fabricated by coating a monolayer PS NS, etching PS NS by butanone, and lifting-off the PS NS, which is covered by Pd metal. The studied device with the pyramid-like Pd structure can significantly enhance the sensing performance. On the other hand, a series of devices with an insertion layer of SiO2-NPs are fabricated and investigated. According to the experimental results, Pd/SiO2 NPs/AlGaN-based (metal/oxide/semiconductor) hydrogen sensor is fabricated by inserting SiO2-NPs layer between Pd/AlGaN interface. The structure can significantly reduce the baseline current in air and service more gas adsorption sites to enhance the sensing performance. Third, the analyses are applied to examine the surfaces morphology with and without nanostructure, including scanning electron microscope (SEM) and atomic force microscopic (AFM) instrument. It further confirms the surface roughness and specific surface area of the device with nanostructure is obviously upgraded. Finally, ZnO NPs-based NO2 gas sensors are investigated. The ZnO NPs have a larger specific surface area and can offer more gas-adsorption sites to significantly enhance sensing performance. And the studied device with calcination treatment is carried out to investigate the effect on sensing characteristic.
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Huang, Ning-Ci, et 黃寧琦. « Study on Nano-Imprinting Guided Mode Resonance Sensor ». Thesis, 2014. http://ndltd.ncl.edu.tw/handle/qer7he.
Texte intégralRésumé :
碩士國立虎尾科技大學
光電與材料科技研究所
102
This paper proposes a Nano-imprinting guided mode resonance (GMR) sensor by a heterodyne interferometer. The manufacturing process utilizes soft lithography, Nano-imprinting technology, and a thermo compressor to imprint the grating. First, Polydimethylsiloxane (PDMS) was applied with soft lithography to reprint a cavity. Then, using SiO2 Nano-imprinting and a thermo compressor give the pressure and temperature to the required level to imprint the grating on the substrate. The parameters of the grating period, the modulation depth, and the TiO2 film thickness were adopted by the simulation software, EM Explorer and GSolver. When the GMR component was done, the heterodyne interferometer and Labview were applied to integrate with stepper motor rotation stages, a lock-in amplifier, an optical power meter, and a computer to run the measurements automatically. It is found that the reflection type of heterodyne interferometer can not adjust sensitivity by altering the angle of analyzer while the transmission type of heterodyne interferometer can adjust sensitivity by altering the angle of the analyzer and the highest sensitivity is 1.8×10-7RIU.
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Chen, gen-yau, et 陳亙佑. « ANSYS based design of nano-scaled fringe capacitive sensor ». Thesis, 2004. http://ndltd.ncl.edu.tw/handle/89694625150465803153.
Texte intégralRésumé :
碩士國立雲林科技大學
機械工程系碩士班
92
In this paper, I used the theory offered by chi-chuan which is design fringe capacitive sensors can analysis nano-scale by ANSYS. I designed a 1.5-ring fringe capacitive sensors to reduce the multi-ring fringe capacitive sensors model simplest and impoved ability of the sensor. Although the sensitivity of the multi-ring fringe capacitive sensors is better than the sensitivity of the single ring. Relatively the analysis model of multi-ring mode is more difficult than single ring mode, and more software and hardware were afforded. Of course, the fabrication is more difficult. So we need to find the simplest multi-ring fringe capacitive sensors model to improve the sensitivity of the single ring mode. And the result of we got is available. I get a new idea from the conclusion that is studied by some people before me. The conclusion is under the same linear error when we want to the sensor have higher sensitivity, the measurable area had became smaller than other. And the sample must approach to sensor. So we have a new idea with the sensor design how to raise sensitivity availably, also qualify enough measurable area. So when we design the 1.5-ring sensor model, we also do some systematic analysis to find the available design method. And we arrived our expectation. We also find when we do nano-scale analysis by ANSYS. There exists some condition. The condition is the feature size can’t differ so much. And we got some result prove our assumption.
48
Chen, Shan-Chien, et 陳善儉. « Multimode Tapered Fiber Sensor Modified With Nano-gold particle ». Thesis, 2009. http://ndltd.ncl.edu.tw/handle/33621002093647084434.
Texte intégralRésumé :
碩士國立中正大學
物理所
97
A fiber biosensor modified by nano-gold particles is made according to the localized surface plasma resonance theorem. The nano-gold particles enhances the sensitivity of the sensor measuring the refractive index (RI) by absorbing and scattering the evanescent wave on the interface between the core and the liquid to be tested. Different research teams have used different approaches to achieve the same goal. In this study, we pursue our goal by modification of the fiber with nano-gold particles. This fiber is either tapered or non-tapered in advance. Note that taper of the fiber may result in the variations of numerical aperture of the fiber, normalized frequency, and the path of propagating light. In the practice of this work, we use an arc discharge system to pull and taper a multimode fiber (core: 400 μm and cladding: 430 μm, both in diameter) or simply remove the cladding. Afterwards, we modify the fiber with spherical nano-gold particles with a diameter of 15 nm. Consequently, when we measure refractive indices of different liquids with this tailored fiber, the light intensity variation with the refractive indices is enlarged. When pull and taper of the abovementioned fiber yield diameters of 300 μm and 200 μm, the latter shows a better sensitivity that the former. Besides, they are both superior to the uniform fiber which is not tapered. Keyword：nano-gold particle, refractive index, tapered fiber, evanescent wave and localized surface plasma resonance.
49
Huang, Jun-Ming, et 黃俊明. « Development of fringe capacitive sensor with nano-scale precision ». Thesis, 2003. http://ndltd.ncl.edu.tw/handle/77219516341821934051.
Texte intégralRésumé :
碩士國立雲林科技大學
機械工程系碩士班
91
It had been proved by this lab that fringe capacitive can do distance measurement up to 10μm precision .In this paper, we used linear motor to further prove the fringe capacitive sensor can measure distance with precision up to 0.5μm. For the range between 0 ~ 20μm , we used piezoelectric actuator to examine 1nm precision capability . For aluminum target with driving signal of 10KHz and 20Vpp and the differential amplifier gain of 100 , the multi-ring sensor would output 0.3mV in 50nm distance variation . The single-ring sensor would output 0.24mV in the same distance variation. Per the linear regression of experiment data , the 4 ring sensor would output 0.0054mV in 1nm variation. The single-ring sensor would output 0.0046mV in same distance variation. We conclude that the fringe capacitive sensor can reach nano-meter precision when measuring aluminum.
50
Wang, Chi-chuan, et 王啟全. « The numerical simulation of nano-scale fringe capacitive sensor ». Thesis, 2003. http://ndltd.ncl.edu.tw/handle/89575910549443312762.
Texte intégralRésumé :
碩士國立雲林科技大學
機械工程系碩士班
91
Finite Element Method (FEM) can be used to analyze engineering problem in areas of mechanics, thermal science, electrical, etc. It fits for both qualitative and quantitative analysis. Per reference [15], R.C. Luo and Z. Chen had derived the mathematical model for single-ring fringe capacitive sensor. For complex fringe capacitive sensor, it is almost impossible to derive the mathematical model analytically. FEM is a way to solve the problem. In this paper, we use finite element analysis software—ANSYS®1 to analyze and model the fringe capacitive sensor. The numerical model was derived and results were compared to the experimental results. Through the understanding in both qualitative and quantitative analysis, research results can help designer to do the design effectively.