6 results on '"Županović, Paško"'
Search Results
2. Collective mode dispersions of organic chain compounds
- Author
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Lošić Željana and Županović Paško
- Subjects
dielectric response ,collective modes ,Physics ,QC1-999 - Published
- 2010
- Full Text
- View/download PDF
3. Dielectric response of metallic crystal made up of highly polarisable molecules: the semi-classical approach
- Author
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Bonačić Lošić Željana and Županović Paško
- Subjects
71.35.aa ,71.45.gm ,77.22.ch ,dielectric response ,collective modes ,polarisation ,local field ,Physics ,QC1-999 - Published
- 2009
- Full Text
- View/download PDF
4. Uloga metalnih nanoklastera u katalizi za pročišćavanje pogonskog plina gorivnih ćelija i spremanje vodika
- Author
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Krstić, Marjan, Županović, Paško, Bonačić-Koutecky, Vlasta, Bilušić, Ante, Sokolić, Franjo, and Kriško, Anita
- Subjects
PRIRODNE ZNANOSTI. Interdisciplinarne prirodne znanosti ,Physics ,udc:577(043.3) ,spremanje i otpuštanje vodika ,Biochemistry. Molecular biology. Biophysics ,fuel cells ,hydrogen storage and release ,NATURAL SCIENCES. Interdisciplinary Natural Sciences ,pročišćavanje pogonskog plina ,feed gas purification ,teorija funkcionala gustoće ,coinage metal hydrides ,Biokemija. Molekularna biologija. Biofizika ,udc:53(043.3) ,ruthenium clusters ,Fizika ,gorivni članci ,rutenijevi klasteri ,density functional theory ,hidridi kovinskih metala - Abstract
Catalyticreactivity of the small transition and coinage metal nanoclusters have been theoretically studied in context of (1) advancing fuel cell technology by developing cost-effective techniques to improve quality of the feed gas as well as (2) safe storage and release of hydrogen in its gaseous state at room temperatures and pressures. In order to address the challenge concerning the improvement the quality of fuel cell feed gas reactions of small ruthenium cationic nanoclusters with CO and H2 has been performed. The origin of the selectivity and outstanding activity of small ruthenium nanoparticles in the catalytic CO methanation reaction has been identified. The second aim of this dissertation is to advance materials for hydrogen storage and their release technology. For this purpose a gas-phase study of fragmentation and catalytic activity of ligated coinage metal hydride nanoclusters has been performed. The theoretical findings based on density functional theory (DFT) are strongly supported by experimental results trough international cooperation. Within thesis we demonstrated that powerful combination of density functional theory and experimental investigations can contribute to intelligently developed new materials and procedures to overcome the challenges hampering worldwide application of fuel cells as ”green” technology of the future., Katalitička reaktivnost malih nanoklastera prijelaznih metala teorijski je istraživana u kontekstu (1) unaprjeđenja tehnologije gorivnih članaka razvijajući jeftine tehnike poboljšanja kvalitete pogonskog plina kao i (2) sigurne pohrane i otpuštanja vodika u plinovitom stanju na atmosferskoj temperaturi i tlaku. Da bi riješili problem nedovoljne kvalitete pogonskog plina gorivnih članaka istraživale su se reakcije malih rutenijevih nanoklastera s CO i H2 . Izvor selektivnosti i izvrsne aktivnosti malih rutenijevih čestica u katalitičkoj CO metanacijskoj reakciji je identificiran. Drugi cilj ove disertacije ja unaprjeđivanje materijala za tehnologiju pohrane i otpuštanja vodika. U tu svrhu provela su se istraživanja fragmentacije i katalitičke aktivnosti ligandiranih metalnih hidridnih nanoklastera. Naša teorijska istraživanja bazirana na teoriji funkcionala gustoće su potvrđena eksperimentalnim rezultatima priznatih istraživačkih grupa kroz međunarodnu suradnju. Unutar ove teze demonstrirali smo da moćna kombinacija našeg teorijskog istraživanja potvrđena eksperimentalnim istraživanjima može doprinijeti inteligentnom razvoju novih materijala i procedura da bi se nadišli problemi koji sprječavaju široku primjenu gorivnih ćelija kao ”zelene” tehnologije budućnosti.
- Published
- 2016
5. Optical properties of noble metal nanocluster hybrids and their potential for biosensing
- Author
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Sanader Maršić, Željka, Županović, Paško, and Bonačić-Koutecky, Vlasta
- Subjects
PRIRODNE ZNANOSTI. Interdisciplinarne prirodne znanosti ,Physics ,linearna i nelinearna optička svojstva ,udc:577(043.3) ,density functional theory, linear and nonlinear optical properties, noble metal nanoclusters ,Biochemistry. Molecular biology. Biophysics ,NATURAL SCIENCES. Interdisciplinary Natural Sciences ,noble metal nanoclusters ,nanoklasteri plemenitih metala ,teorija funkcionala gustoće ,linear and nonlinear optical properties ,Biokemija. Molekularna biologija. Biofizika ,Physics::Atomic and Molecular Clusters ,udc:53(043.3) ,Fizika ,density functional theory - Abstract
Linear and nonlinear optical properties of functionalized forms of noble metal nanoclusters are addressed in this thesis. Noble metal nanoclusters belong to nonscalable regime in which each atom counts. They exhibit molecular like electronic transitions, due to quantum confinement effects, which are strongly influenced by structure. These systems have potential for applications in biosensing and bioimaging, based on their unique optical, electronic and structural properties, after being stabilized either by formation of hybrid systems of metal nanoclusters and biomolecules or protecting nanoclusters by ligands. Using density functional theory and its time dependent version interplay between electronic and structural properties in hybrid nanocluster-biomolecules and ligated clusters has been investigated in order to gain insight into origins of their unique optical properties. To understand optical properties of hybrid systems, silver cluster-histidine complexes, as well as nonlinear properties of ligated silver nanoclusters have been investigated theoretically, and compared with experimental results obtained by expert international collaborators. Within this thesis the concept has been worked out allowing to design systems with large two-photon cross sections which can serve for efficient imaging of tissues and cells. U ovoj tezi su opisana linearna i nelinearna optička svojstva funkcioniziranih oblika nanoklastera plemenitih metala. Nanoklasteri plemenitih metala pripadaju neskalirajućim sustavima u kojima se svaki atom broji. Zbog efekata kvantnog zatočenja, imaju elektronske prijelaze slične onima u molekulama, na koje jako utječe struktura. Zbog svojih jedinstvenih optičkih, elektronskih i strukturnih svojstava, potencijalni su kandidati za primjene u biosenzorici i biooslikavanju, nakon što se stabiliziraju formiranjem hibridnih sustava s biomolekulama ili ih se zaštiti ligandima. U tezi je istraživan je odnos elektronskih i strukturnih svojstava u hibridnim sustavima biomolekula i metalnih klastera kao i u ligandiranim klasterima kako bi se razumio uzrok njihovih jedinstvenih optički svojstava, koristeći teoriju funkcionala gustoće i njenu vremenski ovisnu varijantu. Da bi se razumjela svojstva hibridnih sustava, teorijski su istraživani hibridni sustavi srebrenih klastera i histidina te nelinearna svojstva ligandiranih srebrnih klastera, i uspoređeni s eksperimentalnim rezultatima koje su napravili međunarodni suradnici. Razvijen je koncept koji bi mogao pomoći dizajniranju sustava s jakom dvo-fotonskom apsorpcijom koji bi služili za oslikavanje tkiva i stanica.
- Published
- 2016
6. Foundational principles of predictive statistical mechanics as the basis for theory of irreversibility
- Author
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Kuić, Domagoj and Županović, Paško
- Subjects
načelo najveće informacijske entropije ,statistička mehanika ,neravnotežna teorija ,Hamiltonova dinamika ,termodinamika ireverzibilnih procesa ,Physics ,NATURAL SCIENCES. Physics ,Hamiltonian dynamics ,PRIRODNE ZNANOSTI. Fizika ,nonequilibrium theory ,thermodynamics of irreversible processes ,maximum entropy principle ,udc:53(043.3) ,Fizika ,statistical mechanics - Abstract
Prediktivna statistička mehanika je oblik zaključivanja iz dostupnih podataka, bez dodatnih pretpostavki, koje nastoji predvidjeti reproducibilne pojave. Primjenom prediktivne statističke mehanike na sustave s Hamiltonovom dinamikom razmotren je problem predviđanja makroskopske vremenske evolucije sustava u slučaju nepotpune informacije o mikroskopskoj dinamici. Cilj istraživanja je analizom temeljnih načela prediktivne statističke mehanike produbiti razumijevanje njene opće primjenjivosti u relaciji s drugim teorijama koje nastoje objasniti pojavu ireverzibilnosti. Osnovna hipoteza je da se to može postići detaljnim razmatranjem uloge koju informacija o sustavu ima u razjašnjenju problema ireverzibilnosti. Hipoteza je provjerena kroz analizu i daljnu generalizaciju rezultata osnovnog teorijskog modela. U modelu zatvorenog Hamiltonovog sustava koji uz Liouvilleovu jednadžbu koristi pojmove teorije informacije analiziran je gubitak korelacije izmedu početnih putanja u faznom prostoru i konačnih mikrostanja, i s tim povezan gubitak informacije o stanju sustava. Primjena načela najveće informacijske entropije maksimizacijom uvjetne informacijske entropije, uz ograničenje koje je dano Liouvilleovom jednadžbom usrednjenom po faznom prostoru, omogućila je definiciju brzine promjene entropije bez dodatnih pretpostavki. Početni model je generaliziran te je uvođenjem dodatnih ograničenja koja su ekvivalentna hidrodinamičkim jednadžbama kontinuiteta doveden u izravnu vezu s poznatim rezultatima iz neravnotežne statističke mehanike i termodinamike ireverzibilnih procesa. Dobiveni rezultati upućuju na općenitu primjenjivost načela prediktivne statističke mehanike i njihovu važnost za teoriju ireverzibilnosti. Predictive statistical mechanics is a form of inference from available data, without additional assumptions, for predicting reproducible phenomena. By applying predictive statistical mechanics to systems with Hamiltonian dynamics, a problem of predicting the macroscopic time evolution of the system in the case of incomplete information about the microscopic dynamics was considered. The goal of the research is to deepen the understanding, through the analysis of the fundamental principles of predictive statistical mechanics, of its general applicability in relation to other theories that seek to explain the phenomenon of irreversibility. Basic hypothesis is that this can be achieved with the detailed consideration of the role that information about the system has in the clarification of the problem of irreversibility. The hypothesis was tested through the analysis and further generalization of the results of the basic theoretical model. In a model of a closed Hamiltonian system that with the Liouville equation uses the concepts of information theory, analysis was conducted of the loss of correlation between the initial phase space paths and final microstates, and of the related loss of information about the state of the system. Applying the principle of maximum information entropy by maximizing the conditional information entropy, subject to the constraint given by the Liouville equation averaged over the phase space, allowed a definition of the rate of change of entropy without additional assumptions. Initial model was generalized, and with the introduction of the additional constraints which are equivalent to the hydrodynamic continuity equations, brought into direct connection with the known results from the nonequilibrium statistical mechanics and thermodynamics of irreversible processes. The results obtained in this work suggest the general applicability of the principles of predictive statistical mechanics and their importance for the theory of irreversibility.
- Published
- 2013
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