13 research outputs found
Hierarchically Combined Periodic SERS Active 3D Micro- and Nanostructures for High Sensitive Molecular Analysis
To increase the local field intensity of Raman scattering, gold nanospheres were entrapped in gold coated periodic inverse pyramid structures, being SERS substrates by themselves. The applicability of this complex structure for sensitive molecule detection was proved by comparison of the detected Raman signals with and without particle entrapment. Moreover its relevance in molecular diagnostic was also proposed considering the specific surface functionalisation of the gold nanoparticles
Fabrication of Hybrid Microfluidic System on Transparent Substrates for Electrochemical Applications
In this work the critical aspects of the process sequence developed for fabrication of hybrid polymer microfluidic systems integrating metal electrode pattern and precisely aligned microfluidic structure are discussed in details. Glass and polycarbonate were considered as primary transparent substrate materials for metal (Au, Pt) electrode deposition and the microchannels were formed in multi-layered SU-8 negative photoresist. Poly(dimethylsiloxane) (PDMS) layer was proposed as cover layer to ensure proper sealing and sample inlet formation
Környezetvédelmileg ártalmas anyagok csökkentése arany és ezüst katalizátorral: a szerkezetfüggés modellezése = Gold and silver catalysts for abatement of environmentally harmful materials: modelling the structure dependency
A gĂ©pkocsik kipufogĂł gázaiban nagy mennyisĂ©gű NOx, CO Ă©s szĂ©nhidrogĂ©n-származĂ©k találhatĂł, amelyek ártalmasak az emberi szervezetre. Ezek a komponensek drasztikusan csökkenthetĹ‘k a háromutas katalizátor alkalmazásával. A napjainkban alkalmazott háromutas katalizátorokban Pt, Pd Ă©s Rh találhatĂł cirkĂłnium-oxid stabilizált cĂ©rium-oxid, cirkĂłnium-oxid Ă©s α-alumĂnium-oxid hordozĂłn. A jelen munka cĂ©lja volt Au Ă©s Ag alapĂş katalizátor család fejlesztĂ©se a drága Pt Ă©s Rh helyettesĂtĂ©sĂ©re. Au-Ag kĂ©tfĂ©mes Ă©s az egyfĂ©mes Au Ă©s Ag mintákat SiO2, TiO2 Ă©s CeO2 hordozĂłn állĂtottunk elĹ‘ szol adszorpciĂłs mĂłdszerrel, hogy vizsgáljuk a kĂ©t fĂ©m egymásra hatását az ötvözet fázisban, Ă©s a hordozĂł hatást. Au/ Ă©s Ag/redukálhatĂł fĂ©moxid határfelĂĽletek hatását kĂĽlönbözĹ‘ jĂłl definiált szerkezetű modell katalizátorokon vizsgáltuk. EzĂ©rt Au Ă©s Ag nanorĂ©szecskĂ©ket Ă©s rĂ©tegeket párologtattunk kontrolált körĂĽlmĂ©nyek között a natĂv SiO2-vel borĂtott Si(100) felĂĽletekre kĂĽlönbözĹ‘ mĂłdszerekkel (PLD, MBE, magnetron porlasztás). RedukálhatĂł oxid (pl. TiO2 FeOx Ă©s CeO2) Au-val Ă©s Ag-vel alkotott határfelĂĽletĂ©t többfĂ©le szerkezettel hoztuk lĂ©tre, kĂĽlönbözĹ‘ sorrendben Ă©pĂtve egymásra a rĂ©szecskĂ©s vagy a vĂ©konyrĂ©teg szerkezetű komponenseket. A minták jellemzĂ©sĂ©t kĂĽlönbözĹ‘ mĂłdszerekkel vĂ©geztĂĽk (XPS, AFM, TEM, XRD, SIMS), valamint vizsgáltuk Ĺ‘ket CO oxidáciĂłban Ă©s NOx redukciĂłjában, valamint kiegĂ©szĂtĂ©skĂ©nt glĂĽkĂłz szelektĂv oxidáciĂłjában. | Automotive exhaust gas contains high concentrations of NOx, CO, and hydrocarbons, which are harmful to human health. These components can be reduced drastically by the use of a three-way catalyst. All commercial three way catalysts in use at present are based on Pt, Pd, and Rh on a support comprised of zirconia-stabilized ceria, zirconia and α-alumina. The present project was aimed at developing a novel family of catalysts, based on Au and Ag, the most promising alternative candidates, to replace the more expensive Pt and Rh. We produced SiO2, TiO2 and CeO2 supported bimetallic Au-Ag and monometallic Au and Ag particles using sol preparation and adsorption method to clarify the cooperation of the two metals in the alloyed phase, and the support effect. The effect of the Au/, Ag/reducible metal oxide interface was studied with model catalysts of well defined various structures produced by different techniques. For this purpose Au and Ag nanoparticles and layers were evaporated in controlled ways onto Si(100) wafers using different new techniques (PLD, MBE, magnetron sputtering). Interface of gold and different oxides like TiO2, FeOx and CeO2 were created in different morphology fabricating of the layers or particles of the two components and changing of the order of the deposition. The samples were characterized by different techniques (XPS, AFM, TEM, XRD, SIMS), and studied in CO oxidation and NOx reduction as well as additionally in glucose selective oxidation
Modelling and Characterisation of Droplet Generation and Trapping in Cell Analytical Two-Phase Microfluidic System
Present study analyses the influence of flow characteristics of special water-oil two-phase microfluidic systems regarding the droplet generation, cell encapsulation and trapping processes. Water droplets were dispersed in oil continuous phase with the requirement of precise size distribution to enable effective cell entrapment. The evolving droplet size and the number of encapsulated cells were examined considering the applied flow rate ratios of the two phases. The hydrodynamic behaviour of the microfluidic system was modelled by Finite Element Method (FEM) coupled with particle trajectory calculation applying COMSOL Multiphysics code. The experimental results were compared to the simulation and the applicability of our droplet based cell encapsulating and trapping microfluidic system was characterised
Experiments with Femtosecond Laser on Monocrystalline Silicon
Experiments were performed with femtosecond laser on monocrystalline silicon for different application fields. The small focal spot diameter, the ultra-short pulse length, and the high energy density opens new ways in material processing; the treated material will have smaller heat affected zone (HAZ), and allow more precise, higher quality material processing. Micropillars and LIPSS structures were prepared on monocrystalline silicon in our study
KĂsĂ©rletek szilĂcium egykristályon femtoszekundumos lĂ©zerrel
Femtoszekundumos lĂ©zer segĂtsĂ©gĂ©vel kĂĽlönbözĹ‘ felhasználási cĂ©lokkal kĂsĂ©rleteztĂĽnk szilĂcium egykristályon. A kis fĂłkuszfoltátmĂ©rĹ‘, az ultrarövid impulzushossz Ă©s a nagy energiasűrűsĂ©g Ăşj utakat nyit meg az anyagmegmunkálásban; a kezelt anyagon kisebb lesz a hĹ‘hatásövezet (HAZ), valamint precĂzebb, jobb minĹ‘sĂ©gű anyagmegmunkálás válik lehetĹ‘vĂ©. Munkánk során szilĂcium egykristályra mikrooszlopokat, valamint lĂ©zerindukált periodikus felĂĽleti struktĂşrákat kĂ©szĂtettĂĽnk