Wyniki 1-10 spośród 11 dla zapytania: authorDesc:"DARIUSZ SZMIGIEL"

Development of REFET for Differential Measurements of pH in a Fluidic System DOI:10.12915/pe.2014.11.39

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This paper describes the fabrication of the REFET structure by means of plasma oxidation of silicon nitride and discusses the results of differential pH measurements and quasi-REFET characterization. The source follower measurement circuit and housings for the fluidic systems are shown. The pH measurement of the diluted hydrochloric acidis presented as an exemplary application. . Streszczenie. W pracy przedstawiono dotychczasowy rozwój technologii REFETów. Opisano wytwarzanie REFETa metodą utleniania plazmowego warstwy azotkowej. Zaprezentowano układ pomiarowy wtórnika źródłowego i obudowy przepływowe. Podano wyniki kwalifikacji kwazi-REFETów i różnicowych pomiarów pH. Zaproponowano zastosowanie przyrządu wraz z pseudoreferencyjną elektrodą Pt do pomiarów w rozcieńczonym HCl. Rozwój technologii REFETów z przeznaczeniem do pomiaru pH Keywords: REFET, ISFET, Reference electrode. Słowa kluczowe: REFET, ISFET, elektroda referencyjna. doi:10.12915/pe.2014.11.39 Introduction Ion Sensitive Field Effect Transistors (ISFET) are used as a versatile basic devices for fabrication of various chemical and biochemical sensors. According to this concept a liquid analyte is used as a gate electrode of the transistor. Analyte potential is controlled by means of a reference electrode. The Ag/AgCl reference electrode exhibits stability in a water solution of chloride ions when the concentration is kept constant. The electrode is usually placed in a tube filled with KCl solution and separated from the analyte by a porous membrane. This arrangement of the reference electrode makes miniaturization hardly possible. Simple metal electrode shows a potential drop in an electrolyte and the range of changes depends on the electrolyte composition, type of metal and the state of its surface. However, the potential drop is usually unstable and difficult to observe. The problem can be overcome by differential measurements using an ISFET and a Reference FET (RE[...]

Charakterystyka chemisorpcyjna i katalityczna układów ruten/węgiel przeznaczonych do syntezy amoniaku

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Omówiono wpływ tekstury modyfikowanego termicznie węgla aktywnego na dyspersję osadzonego rutenu oraz właściwości katalityczne otrzymanych układów Ru/C w reakcjach syntezy i rozkładu amoniaku. Wykazano, że średni wymiar krystalitów rutenu wyznaczony metodami chemisorpcyjnymi jest tym mniejszy, im bardziej rozwinięta jest tekstura węgla. Stwierdzono, że cez jest niezwykle efektywnym promoto[...]

Design and realization of a microfluidic capillary sensor based on a silicon structure and disposable optrodes

  During the last years microfluidic sensors that use optical capillaries have gained an increasing importance due to their new applications as diagnostic tool in biotechnology, medicine and in environmental sciences. This was possible because the capillary enables multiparametric sensing [1-7] contrary to the classical optical fiber sensors [8], which find applications in physical measurements such as pressure and also magnetic field [9]. In this paper the improvements in the design of microfluidic sensors that use local heating in optical capillaries as a base of multiparametric diagnostics is presented [4]. The application of local heating opened interesting new possibilities for the sensors, that do not use any chemical sensitive layers or reagents, while raising specific issues relating to their construction, materials and technology [5]. The mentioned sensors can be used for in situ diagnostic in medicine and veterinary and as biofuel usability testers [10-12].The proposed microfluidic capillary sensor consists of a stabilized-intensity light source unit, a testing head with replaceable optical capillary, a heater and a detection unit. The optical capillary performs the functions of a liquid sample holder and at the same time of a multiparametric sensing element. The sensor operates in a multiparametric sensing mode, monitoring, registering and processing the indirect information such as the index of refraction, the boiling point, the vapour pressure, the heat capacity, the heat of fusion, the viscosity, the surface tension of the liquid and turbidity changes in a thermally forced measuring cycle. The measuring cycle is initiated by applying local heating to the sample [5]. The measuring cycle is controlled indirectly by changes in optical signals and temperatures [10]. The raw optical data are processed by an optoelectronic ci[...]

Nośnikowe katalizatory rutenowe do niskociśnieniowej syntezy amoniaku

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Zbadano aktywność katalityczną kilku katalizatorów rutenowych w reakcji syntezy amoniaku. Jako nośników rutenu użyto tlenku magnezu o powierzchni wewnętrznej 94 m2/g, spinelu magnezowo- glinowego (96 m2/g), azotku boru (190 m2/ g) oraz wysokopowierzchniowego, częściowo zgrafityzowanego węgla aktywnego (1188 m2/g). Wszystkie katalizatory (ok. 9% Ru) promowane były barem. Testy kinetyczne w [...]

Oscylator pierścieniowy CMOS jako układ detekcji odkształcenia nanoczułych mikrosond krzemowych

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Standardowymi rozwiązaniami elektronicznych układów pomiarowych wychylenia mikrobelek krzemowych są piezorezystory skonfigurowane w mostki Wheastone'a [1, 2] lub tranzystory MOS [3, 4]. Istnieje możliwość wykorzystania, jako układu detekcyjnego, bardziej złożonego układu CMOS - oscylatora pierścieniowego. Układ taki reaguje na odkształcenie belki zmianą częstotliwości drgań własnych i [...]

Rapid prototyping of electrostatically-driven MEMS

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In general, design and manufacturing of MEMS is a complex, expensive and time consuming process. Usually, it requires a number of iterative steps for verification of initial concepts and for determination of the properties of structural materials [1]. This process has been significantly boosted by several commercial MEMS design and simulation software tools that have been developed in the last decade, such as COVENTORWARE ® or INTELLISENSE® [2, 3]. Still, when using such software, it is very difficult to combine electromechanical properties of MEMS devices with electrical properties of semiconductors. In this case, a classical scheme, namely with a standard manufacturing cycle: design, fabrication, testing may be the only feasible one. For complex designs, this may cause long times to market. In this paper we present a very simple approach that[...]

Design and manufacturing of heterogeneous microsystems for micro- and nanotechnology applications

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The potential and growth of microsystem require integration of mechanical, electrical, optical and many more domains within the small dimensions associated with very large scale integration (VLSI). The behavior of the overall system is not just the simple connection of separate mechanical and electrical behaviors, but the simultaneous combination of mechanical, electrical and optical behaviors. The integration of modern MEMS has to be considered on various levels: - materials used for microsystem construction, - processes used for fabrication of the system, - mechanical and electrical properties of the elements of microsystem, - function of overall integrated microsystem including packaging. Therefore modern tool for multi-domain, heterogeneous microsystem modeling and simulation has to allow the designer take into account all these aspects of integration. Modern methodology of MEMS design presented in this paper is based on a system-level, top-down MEMS design process [1]. The objectives of this method are to optimize the function of the devices and to minimize development time and cost by avoiding unnecessary design cycles and foundry runs. This methodology (Fig.1a) uses an initial set of MEMS re quirements to select a design and fabrication approach. Instead of using a layoutdrawing tool to create a 2D model, high-level design techniques use a graphical schematic capture tool to position and connect the model symbols that represent functional blocks (masses, plates, electrodes or micro-fluidic parts) with underlying analytical formula. Because the simulations are run using code-based, six Degree-Of-Freedom (DOF) behavioral models, instead of FEM based or BEM-based partial differential equation models, the simulation time is reduced by orders of magnitude. Once the design is complete a device layout can be generated automatically from the high level description. In next step, 3D PDE Design and manufacturing of h[...]

Integrated thermal probe for SThM investigation of micro- and nanoelectronic devices

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Modern technology of micro/nanoelectronic components, sensors and MEMS/NEMS (Micro/Nano-Electro-Mechanical- Systems) requires increasingly the control of materials at the sub-micrometer scale down to the nanometer scale. According the ITRS roadmap for silicon-based semiconductor devices, the power dissipation of chips exceeds 300 W, with localized heat fluxes even above 500 W/cm2. Therefore, local thermal properties of the involved structures are of high interest; and sub-100 nm resolution is required for most of the studies. Particularly, the heat transfer phenomena, including e.g. phonon heat conduction mechanisms in micro- and nanostructures, have to be understood since they differ significantly from that on the macroscale. The invention of the scanning tunneling microscope (STM) [1] and the atomic force microscope (AFM) [2] have allowed sub-micrometer and even atomic scale spatially resolved imaging of surfaces. The spatial resolution of these near-field techniques is only limited by the active area of the sensing tip (which in the case of STM may only be a few atoms at the end of a metal wire). As described by Dinwiddie and Pylkki in 1994, first scanning thermal microscopy (SThM) probes employed resistance thermometry to measure thermal properties [3]. These probes were fashioned and made from Wollaston wire consisting of a thin platinum core (ca. 5 μm in diameter) surrounded by a thick silver sheath (ca. 75 μm). Because of its high endurance, the Wollaston probe is attractive for microsystem diagnostics [4, 5], however the active area in the range of a few micrometers does not fulfill the requirements regarding spatial resolution and quantitative thermal properties for micro- and nano-scale components. In this paper we propose a novel AFM cantilever combined with a SThM resistive tip. Moreover, the technology sequence developed for manufacturing of AFM/SThM probes offers highly reproducible, cost-effective b[...]

Modelowanie i wytwarzanie mikrosystemów dla zastosowań w chemii i diagnostyce biomedycznej

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W artykule przedstawiono procesy technologiczne mikroinżynierii krzemowej wykorzystane do wytwarzania przyrządów opracowywanych w ramach projektu MNS-DIAG. Kluczowymi procesami dla wytwarzania opracowywanych w ramach tego projektu demonstratorów są: głębokie plazmowe trawienie podłoża krzemowego, procesy łączenia płytek podłożowych z innymi płytkami krzemowymi, ceramicznymi lub szklanymi, procesy elektrochemicznego osadzania metali szlachetnych oraz procesy nakładania i kształtowania warstw polimerowych. Abstract. The development of silicon technology over the last few decades has enabled production of complex integrated circuits and has also contributed to the development of microsystems containing sensors, actuators, and signal processing circuits. Currently, microsystems based on silicon technology, complemented by processes specific to MEMS technology, are widely used in both automotive as well as in chemistry, biology or medicine. The paper presents processes used to manufacture silicon microsystems developed in the fame of the project “Microsystems for biology, chemistry and medical applications". The project goal is to develop a range of biomedical devices and chemical sensors: lab on a chip for determination of psychotropic drugs in saliva samples, diagnostic instruments for analysis of body secretion for fertility and pathological states monitoring, diagnostic instruments for evaluation of bovine embryos, microreactors for cell culture, arrays of chemical sensors for detection of Gramnegative bacteria and MEMS for medical diagnostic equipment. Key manufacturing processes used for fabrication of these devices are: deep plasma etching of silicon substrate, bonding of silicon, ceramic or glass substrates, electrochemical deposition and patterning of noble metals and coating and patterning of polymer layers on silicon and glass substrates. (Preparation Modeling and manufacturing of microsystems for applications in chemistry and bio[...]

Mikroprzepływowe immunoczujniki z detekcją amperometryczną

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W przypadku nowoczesnych urządzeń analitycznych, takich jak bioczujniki bardzo istotnymi cechami są: niski koszt pojedynczego testu, jak najkrótszy czas w którym można uzyskać wyniki, wielofunkcyjność, duża czułość oraz możliwość analizowania złożonych próbek. Można to uzyskać poprzez zastosowanie układu mikroprzepływowego, amperometrycznego systemu detekcji oraz analitycznych technik immunoenzymatycznych, takich jak ELISA (Enzyme-Linked Immunoassay), czy ELISPOT (Enzyme-Linked Immuno-Spot Assay) [1]. W przypadku detekcji amperometrycznej najczęściej używane są immunoglobuliny z klasy G (IgG) znakowane enzymami, takimi jak: fosfataza alkaliczna, peroksydaza, katalaza, laktaza i galaktozydaza. Istnieje szeroki wybór testów ELISA nadający się do aplikacji w czujnikach do oznacz[...]

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