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Littérature scientifique sur le sujet « DFT and TB »

Auteur : Grafiati
Publié le 11 janvier 2025

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Articles de revues sur le sujet "DFT and TB"

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Duarte, Hélio A., Thomas Heine, and Gotthard Seifert. "DFT ×TB − a unified quantum-mechanical hybrid method." Theoretical Chemistry Accounts 114, no. 1-3 (2005): 68–75. http://dx.doi.org/10.1007/s00214-005-0645-0.

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Bhatt, Nisarg K., A. B. Patel, A. Y. Vahora, P. R. Vyas, B. Y. Thakore, and Ashvin R. Jani. "Structural and Vibrational Properties of FeO Using First-Principles." Advanced Materials Research 665 (February 2013): 49–52. http://dx.doi.org/10.4028/www.scientific.net/amr.665.49.

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We have studied the equation of states and vibrational properties of FeO using DFT based plane-wave pseudopotential (PW-DFT) within the generalized gradient approximation. The calculated cohesive properties at ambient condition, namely, lattice constant (a0), bulk modulus (B0) and its first pressure derivative (), are reported for B1-phase of FeO, in agreement with previous experimental and other theoretical results. A linear-response approach to the density functional theory was used to derive the phonon frequencies and phonon density of state (p-dos). Further, in order to calculate both static and dynamic equations of states, nearest-neighbour second-moment tight-binding energy model (TB-SMA) was used. Parameters of the present TB-SMA model were determined by the presentab initiopseudopotential calculations. It is found that the present simple TB-SMA scheme is able to mimic shock Hugoniot for such oxides correctly.
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Asadi-Aghbolaghi, Narges, Johann Pototschnig, Zahra Jamshidi, and Lucas Visscher. "Effects of ligands on (de-)enhancement of plasmonic excitations of silver, gold and bimetallic nanoclusters: TD-DFT+TB calculations." Physical Chemistry Chemical Physics 23, no. 33 (2021): 17929–38. http://dx.doi.org/10.1039/d1cp03220h.

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Chen, Peng, Jin-Yu Zou, and Bang-Gui Liu. "Intrinsic ferromagnetism and quantum anomalous Hall effect in a CoBr2monolayer." Physical Chemistry Chemical Physics 19, no. 21 (2017): 13432–37. http://dx.doi.org/10.1039/c7cp02158e.

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The electronic, magnetic, and topological properties of a CoBr<sub>2</sub>monolayer are studied in the framework of density-functional theory (DFT) combined with tight-binding (TB) modeling in terms of the Wannier basis.
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Shah, Saima Ahmad, Mudasser Husain, Nasir Rahman, et al. "Insight into the exemplary structural, elastic, electronic and optical nature of GaBeCl3 and InBeCl3: a DFT study." RSC Advances 12, no. 13 (2022): 8172–77. http://dx.doi.org/10.1039/d2ra00943a.

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In the scheme of density functional theory (DFT), Structural, elastic, electronic, and optical properties calculations of GaBeCl3 and InBeCl3 are carried out using Tran–Blaha modified Becke–Johnson exchange potential approximation (TB-mBJ) installed in Wein2k software.
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Mendoza-Huizar, Luis. "A DFT study of the chemical reactivity of thiobencarb and its oxidized derivatives in aqueous phase." Journal of the Serbian Chemical Society 83, no. 9 (2018): 981–93. http://dx.doi.org/10.2298/jsc170927034m.

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In the present work, the global and local reactivity of S-(4-chlorobenzyl)- N,N-diethylthiocarbamate (TB) and its oxidized derivatives (sulfone (TBSu) and sulfoxide (TBS) were analyzed. In addition, the chemical reactivities of the dechlorinated forms of TB (DTB), TBSu (DTBSu) and TBS (DTBS) were studied. The calculations were performed at the wB97XD/6- -311++G(2d,2p) level of theory in the aqueous phase. The condensed Fukui functions indicated that for TB and DTB, the most preferred sites for donating electron in a reaction are located on the S and N atoms, while the most reactive sites for accepting electrons are associated with the aromatic ring (AR). For TBS and DTBS, the more reactive sites are located on AR, S and AR for nucleophilic, electrophilic and free radical attacks, respectively. In the case of TBSu and DTBSu, the results showed AR to be the more reactive zone for the three kinds of attacks. These last results suggest that cleavage of the C?S bond in TB, TBS and their dechlorinated forms is favored by electrophilic attacks. Additionally, the obtained results suggest that in TB, it is plausible that the cleavage of the C?N is favored on attack of this molecule by electrophiles.
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Rai, D. P., A. Shankar, Sandeep Sandeep, M. P. Ghimire, R. Khenata, and R. K. Thapa. "Study of the enhanced electronic and thermoelectric (TE) properties of ZrxHf1−x−yTayNiSn: a first principles study." RSC Advances 5, no. 115 (2015): 95353–59. http://dx.doi.org/10.1039/c5ra12897h.

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A density functional theory (DFT) approach employing generalized gradient approximation (GGA) and the modified Becke Johnson (TB-mBJ) potential has been used to study the electronic and thermoelectric (TE) properties of Zr<sub>x</sub>Hf<sub>1−x−y</sub>Ta<sub>y</sub>NiSn.
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Rahnamaye Aliabad, H. A., Z. Barzanuni, S. Ramezani Sani, et al. "Thermoelectric and phononic properties of (Gd, Tb) MnO3 compounds: DFT calculations." Journal of Alloys and Compounds 690 (January 2017): 942–52. http://dx.doi.org/10.1016/j.jallcom.2016.08.167.

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Gao, Fei, Eric J. Bylaska, and William J. Weber. "Defect Properties in GaN: Ab Initio and Empirical Potential Calculations." Materials Science Forum 475-479 (January 2005): 3087–90. http://dx.doi.org/10.4028/www.scientific.net/msf.475-479.3087.

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The defect properties and atomic configurations in GaN have been comparatively investigated using density functional theory (DFT) and molecular dynamics method with two representative potentials. The DFT calculations show that the relaxation of vacancies is generally small, but the relaxation around antisite defects is large. The N interstitials, starting from any possible configurations, eventually relax into a N+-N&lt; 0 2 11 &gt; split interstitial. In the case of Ga interstitials, the most stable configuration is a Ga octahedral interstitial, but the Ga+-Ga&lt; 0 2 11 &gt; split interstitial can bridge the gap between non-bounded Ga atoms. The formation energies of vacancies and antisite defects obtained using the Stillinger-Weber potential (SW) are in reasonable agreement with those obtained by DFT calculations, whereas the Tersoff-Brenner (TB) potential better describes the behavior of N interstitials.
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Asadi-Aghbolaghi, Narges, Robert Rüger, Zahra Jamshidi, and Lucas Visscher. "TD-DFT+TB: An Efficient and Fast Approach for Quantum Plasmonic Excitations." Journal of Physical Chemistry C 124, no. 14 (2020): 7946–55. http://dx.doi.org/10.1021/acs.jpcc.0c00979.

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Thèses sur le sujet "DFT and TB"

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Serrano, richaud Elisa. "Modelling electronic and optical properties of 2D heterostructures." Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASP121.

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Le graphène (Gr) et le nitrure de bore hexagonal (hBN) ont un paramètre de réseau similaire (décalage de ~1,5 %) et des propriétés différentes : le Gr est un métal connu pour sa conductivité élevée et le hBN est un isolant à grand écart (~6eV) avec une forte émission d'UV. En raison de ces deux remarques, ils sont des candidats parfaits pour être empilés côte à côte dans une hétérostructure latérale au lieu d'être empilés l'un sur l'autre dans une hétérostructure verticale plus courante. Dans cette thèse, je m'intéresserai à la modélisation des propriétés électroniques et optiques des hétérostructures latérales composées de nanorubans successifs de graphène et de nitrure de bore (AGBN). Cependant, lors de la synthèse de ce type d'hétérostructures, des défauts, tels que des rugosités ou des défauts non-hexagonaux, peuvent apparaître à l'interface et affecter les propriétés des AGBN.Dans la première partie de la thèse, je combinerai des techniques ab-initio telles que la théorie de la fonctionnelle de la densité (DFT) et un modèle perturbatif de liaison étroite (TB) pour étudier la sensibilité opposée et complémentaire de la largeur de la fente des nanorubans armchair Gr et hBN isolés (AGNR et ABNNR) en fonction de différents stimuli.Dans les parties suivantes, je présenterai la structure électronique de l'AGBN réalisée avec la DFT et le spectre optique calculé par GW et l'équation de Bethe-Salpeter (BSE). Je passerai des caractéristiques générales, comme la structure de bande, à l'explication détaillée du rôle de chaque matériau et du confinement caractéristique de l'exciton dans la partie Gr des hétérostructures.Parallèlement à cette étude, je vais paramétrer un modèle TB semi-empirique et fixer ses limites de validité pour décrire le spectre d'absorption de l'AGBN dans l'approximation des particules indépendantes. Par conséquent, je dois établir une correspondance entre les pics excitoniques sur les spectres d'absorption BSE et les transitions dans les spectres IP, ce qui nous permettra d'estimer les effets excitoniques à partir des spectres TB IP. En particulier, cette approche sera utilisée dans la dernière partie de la thèse pour caractériser l'impact d'une faible rugosité à l'interface ou de défauts non-hexagonaux comme les Stone-Wales ou les divacances<br>Graphene (Gr) and hexagonal boron nitride (hBN) have a similar lattice parameter (~1.5% mismatch) and different properties , Gr is a metal known by its high conductivity and hBN is a large gap insulator ~6eV) with a strong UV emission. Due to these two remarks, they are perfect candidates to be stacked side-by-side in a lateral heterostructures instead of one of the top of the other in a more common vertical heterostructure. In this thesis I will be interested at modelling the electronic and optical properties of lateral heterostructures composed of successive armchair graphene and boron nitride nanoribbons (AGBN). However, during the synthesis of this kind of heterostructures defects, such as roughness or non-hexagonal defect, may appear at the interface affecting to the properties of AGBN.In the first part of the thesis, will combine ab-initio techniques such a density functional theory (DFT) and a perturbative tight-binding (TB) modem to study the opposite and complementary sensitivity of the gapwidth of isolated Gr and hBN armchair nanoribbons (AGNR and ABNNR) upon different stimuli.In the next parts I will present the electronic structure of AGBN carry out with DFT and optical spec-trum calculated by GW and the Bethe-Salpeter equation (BSE). I will revise from the general features, like the band structure, to explaining in detail the role of each material and the characteristic confining of the exciton in the Gr part of the heterostructures.Parallel to this study, I will parametrise a semi-empirical TB model and set its limits of validity to de-scribe the absorption spectrum of AGBN in the independent-particle approximation. Therefore, I have to set a correspondence between excitonic peaks on the BSE absorption spectra and transitions in IP spec-tra will allow us to estimate excitonic effects from the TB IP spectra. In particular, this approach will be used in the last part of the thesis to finally characterise the impact of weak roughness at the interface or non-hexagonal defects like Stone-Wales or divacancies
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Garabato, Brady D. "Synthesis and Computational Studies of a New Class of Lanthanide Niobate Cluster : [Ln4(H2O)8(SO4)5(NbO3)2]+3H2O; Ln= Dy, Tb." TopSCHOLAR®, 2013. http://digitalcommons.wku.edu/theses/1294.

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Polyoxoniobates (PONbs) are a small family of highly electron-rich clusters. The development of new solids composed of these clusters have applications in green energy and electronics. However, the high charge environment of PONbs typically requires alkaline synthetic conditions that are unsuitable for introducing other metals and organic molecules, making synthesis of new systems difficult. To date, very few transition metals and organic ligands have been incorporated into these PONb solids, and lanthanide metal inclusion, which generally improves photoconductivity due to longlived f-orbital excitations, has not yet been fully realized. Here, the synthesis of a new class of lanthanide niobate cluster [Ln4(H2O)8(SO4)5(NbO3)2]·3H2O; Ln= Dy, Tb under acidic conditions is reported. Structures were determined by crystallography and time-dependent density functional theory (TD-DFT) was used to provide insight into photo-induced electronic transitions. Supporting computational methods that are currently being developed for modeling these emerging cluster systems are described.
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Zienert, Andreas. "Electronic Transport in Metallic Carbon Nanotubes with Metal Contacts." Doctoral thesis, Universitätsbibliothek Chemnitz, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-108205.

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The continuous migration to smaller feature sizes puts high demands on materials and technologies for future ultra-large-scale integrated circuits. Particularly, the copper-based interconnect system will reach fundamental limits soon. Their outstanding properties make metallic carbon nanotubes (CNTs) an ideal material to partially replace copper in future interconnect architectures. Here, a low contact resistance to existing metal lines is crucial. The present thesis contributes to the theory and numerical description of electronic transport in metallic CNTs with metal contacts. Different theoretical approaches are applied to various contact models and electrode materials (Al, Cu, Pd, Ag, Pt, Au) are compared. Ballistic transport calculations are based on the non-equilibrium Greens function formalism combined with tight-binding (TB), extended Hückel theory (EHT) and density functional theory (DFT). Simplified contact models allow a qualitative investigation of both the influence of geometry and CNT length, and the strength and extent of the contact on the transport properties. In addition, such simple contact models are used to compare the influence of different electronic structure methods on transport. It is found that the semiempirical TB and EHT are inadequate to quantitatively reproduce the DFT-based results. Based on this observation, an improved set of Hückel parameters is developed, which remedies this insufficiency. A systematic investigation of different contact materials is carried out using well defined atomistic metal-CNT-metal structures, optimized in a systematic way. Analytical models for the CNT-metal interaction are proposed. Based on that, electronic transport calculations are carried out, which can be extended to large systems by applying the computationally cheap improved EHT. The metal-CNT-metal systems can then be ranked by average conductance: Ag ≤ Au &lt; Cu &lt; Pt ≤ Pd &lt; Al. This corresponds qualitatively with calculated contact distances, binding energies and work functions of CNTs and metals. To gain a deeper understanding of the transport properties, the electronic structure of the metal-CNT-metal systems and their respective parts is analyzed in detail. Here, the energy resolved local density of states is a valuable tool to investigate the CNT-metal interaction and its influences on the transport<br>Die kontinuierliche Verkleinerung der Strukturgrößen stellt hohe Anforderungen an Materialen und Technologien zukünftiger hochintegrierter Schaltkreise. Insbesondere die Leistungsfähigkeit kupferbasierte Leitbahnsystem wird bald an fundamentale Grenzen stoßen. Aufgrund ihrer hervorragenden Eigenschaften könnten metallische Kohlenstoffnanoröhren (engl. Carbon Nanotubes, CNTs) Kupfer in zukünftigen Leitbahnsystemen teilweise ersetzen. Dabei ist ein geringer Kontaktwiderstand mit vorhandenen Leitbahnen von entscheidender Bedeutung. Die vorliegende Arbeit liefert grundlegende Beiträge zur Theorie und zur numerischen Beschreibung elektronischer Transporteigenschaften metallischer CNTs mit Metallkontakten. Dazu werden verschiedene theoretische Ansätze auf diverse Kontaktmodelle angewandt und eine Auswahl von Elektrodenmaterialen (Al, Cu, Pd, Ag, Pt, Au) verglichen. Die Beschreibung ballistischen Elektronentransports erfolgt mittels des Formalismus der Nichtgleichgewichts-Green-Funktionen in Kombination mit Tight-Binding (TB), erweiterter Hückel-Theorie (EHT) und Dichtefunktionaltheorie (DFT). Vereinfachte Kontaktmodelle dienen der qualitativen Untersuchung des Einflusses von Geometrie und Länge der Nanoröhren, sowie von Stärke und Ausdehnung des Kontaktes. Darüber hinaus erlauben solch einfache Modelle mit geringem numerischen Aufwand den Einfluss verschiedener Elektronenstrukturmethoden zu untersuchen. Es zeigt sich, dass die semiempirischen Methoden TB und EHT nicht in der Lage sind die Ergebnisse der DFT quantitativ zu reproduzieren. Ausgehend von diesen Ergebnissen wird ein verbesserter Satz von Hückel-Parametern generiert, der diesen Mangel behebt. Die Untersuchung verschiedener Kontaktmaterialien erfolgt an wohldefinierten atomistischen Metall-CNT-Metall-Strukturen, welche systematisch optimiert werden. Analytische Modelle zur Beschreibung der CNT-Metall-Wechselwirkung werden vorgeschlagen. Darauf aufbauende Berechnungen der elektronischen Transporteigenschaften, können mit Hilfe der verbesserten EHT auf große Systeme ausgedehnt werden. Die Ergebnisse ermöglichen eine Reihung der Metall-CNT-Metall-Systeme hinsichtlich ihrer Leitfähigkeit: Ag ≤ Au &lt; Cu &lt; Pt ≤ Pd &lt; Al. Dies korrespondiert qualitativ mit berechneten Kontaktabständen, Bindungsenergien und Austrittarbeiten der CNTs und Metalle. Zum tieferen Verständnis der Transporteigenschaften erfolgt eine detaillierte Analyse der elektronischen Struktur der Metall-CNT-Metall-Systeme und ihrer Teilsysteme. Dabei erweist sich die energieaufgelöste lokale Zustandsdichte als nützliches Werkzeug zur Visulisierung und zur Charakterisierung der Wechselwirkung zwischen CNT und Metall sowie deren Einfluss auf den Transport
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Hellström, Sandra, and Frida Nyberg. "Tbc, ett globalt hot : Sjuksköterskans arbete för att främja följsamhet och minska resistensutveckling av mykobakterium tuberkulosis." Thesis, Halmstad University, School of Social and Health Sciences (HOS), 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-3722.

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<p>Tuberkulos (tbc) är en luftburen droppsmitta orsakad av mykobakterium tuberkulosis. Tbc är den sjukdom som efter AIDS orsakar flest dödsfall, trots att botande behandling finns. Behandlingen är krävande för den tbc-smittade att genomgå och bygger på en kombination av en rad antibiotika som måste intas under minst sex månader. Ett avvikande i behandlingen kan resultera i att mykobakterium tuberkulosis blir resistent mot de ordinerade antibiotika. Följsamhet av långtidsbehandlingar som tbc-behandling graderas till 50 %. Syftet med litteraturstudien var att ur ett globalt perspektiv beskriva hur sjuksköterskan kan påverka följsamhet vid tbc-behandling i syfte att minska resistensutvecklingen av mykobakterium tuberkulosis. Studien genomfördes som en litteraturstudie där 12 vetenskapliga artiklar granskades och analyserades. Resultatet visar tydligt att specifika faktorer påverkar följsamhet och därigenom resistensutvecklingen. Faktorerna innefattar patientundervisning, behandlingsstrategier, omgivningens påverkan och stöd.  Undervisningen resulterar i att patienten får ökad förståelse för behandlingen. För att minska stigmatiseringen och det lidande den innebär för den tbc-smittade är även omgivningen i behov av ökad kunskap och information om tbc. Ett flertal studier visar att DOTS-strategin är betydelsefull för ökad följsamhet vid antituberkulos behandling. Litteraturstudien medför ett förslag om att sjuksköterskeprogrammet ska öka fokuseringen på följsamhet vid läkemedelsanvändning. Sjuksköterskan är i behov av att redan under grundutbildningen få kunskap om ansvarsfull antibiotikahantering som leder till en följsamhetsomtanke.</p><br><p>Tuberculosis (TB) is an airborne droplet infection caused by mycobacterium tuberculosis. TB is the disease after AIDS that is most deadly, even though curative treatment exists. The treatment is demanding for the TB-infected to undergo and consists of a combination of a number of antibiotics that must be administered for at least six months. A dissenting in anti-tuberculosis treatment might result in mycobacterium tuberculosis strains that are resistant to antibiotics. As adherence to long-term treatment is graded at a low percentage (50 %) the aim of the literature study was from a global perspective to develop a working-strategy for nurses that promote compliance in TB-treatment in order to reduce resistance development of mycobacterium tuberculosis. The study was conducted as a literature study where 12 research articles were reviewed and analyzed. The results describe specific factors that are essential to compliance. These factors comprise patient education, treatment strategies, social influences and support. As knowledge gives the patient a better understanding for the treatment it provokes compliance. The social environment of the TB-infected patient demands increased knowledge in order to reduce stigma. Several studies show that the DOTS strategy is important for increasing compliance in anti-tuberculosis treatment. The literature study results in a proposal for the nursing program to focus more on compliance in taking medication. The nursing program’s attendants need to gain knowledge about prudent antibiotic treatment that leads to a compliance concern.</p>
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Zienert, Andreas. "Electronic Transport in Metallic Carbon Nanotubes with Metal Contacts." Doctoral thesis, 2012. https://monarch.qucosa.de/id/qucosa%3A19863.

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The continuous migration to smaller feature sizes puts high demands on materials and technologies for future ultra-large-scale integrated circuits. Particularly, the copper-based interconnect system will reach fundamental limits soon. Their outstanding properties make metallic carbon nanotubes (CNTs) an ideal material to partially replace copper in future interconnect architectures. Here, a low contact resistance to existing metal lines is crucial. The present thesis contributes to the theory and numerical description of electronic transport in metallic CNTs with metal contacts. Different theoretical approaches are applied to various contact models and electrode materials (Al, Cu, Pd, Ag, Pt, Au) are compared. Ballistic transport calculations are based on the non-equilibrium Greens function formalism combined with tight-binding (TB), extended Hückel theory (EHT) and density functional theory (DFT). Simplified contact models allow a qualitative investigation of both the influence of geometry and CNT length, and the strength and extent of the contact on the transport properties. In addition, such simple contact models are used to compare the influence of different electronic structure methods on transport. It is found that the semiempirical TB and EHT are inadequate to quantitatively reproduce the DFT-based results. Based on this observation, an improved set of Hückel parameters is developed, which remedies this insufficiency. A systematic investigation of different contact materials is carried out using well defined atomistic metal-CNT-metal structures, optimized in a systematic way. Analytical models for the CNT-metal interaction are proposed. Based on that, electronic transport calculations are carried out, which can be extended to large systems by applying the computationally cheap improved EHT. The metal-CNT-metal systems can then be ranked by average conductance: Ag ≤ Au < Cu < Pt ≤ Pd < Al. This corresponds qualitatively with calculated contact distances, binding energies and work functions of CNTs and metals. To gain a deeper understanding of the transport properties, the electronic structure of the metal-CNT-metal systems and their respective parts is analyzed in detail. Here, the energy resolved local density of states is a valuable tool to investigate the CNT-metal interaction and its influences on the transport.<br>Die kontinuierliche Verkleinerung der Strukturgrößen stellt hohe Anforderungen an Materialen und Technologien zukünftiger hochintegrierter Schaltkreise. Insbesondere die Leistungsfähigkeit kupferbasierte Leitbahnsystem wird bald an fundamentale Grenzen stoßen. Aufgrund ihrer hervorragenden Eigenschaften könnten metallische Kohlenstoffnanoröhren (engl. Carbon Nanotubes, CNTs) Kupfer in zukünftigen Leitbahnsystemen teilweise ersetzen. Dabei ist ein geringer Kontaktwiderstand mit vorhandenen Leitbahnen von entscheidender Bedeutung. Die vorliegende Arbeit liefert grundlegende Beiträge zur Theorie und zur numerischen Beschreibung elektronischer Transporteigenschaften metallischer CNTs mit Metallkontakten. Dazu werden verschiedene theoretische Ansätze auf diverse Kontaktmodelle angewandt und eine Auswahl von Elektrodenmaterialen (Al, Cu, Pd, Ag, Pt, Au) verglichen. Die Beschreibung ballistischen Elektronentransports erfolgt mittels des Formalismus der Nichtgleichgewichts-Green-Funktionen in Kombination mit Tight-Binding (TB), erweiterter Hückel-Theorie (EHT) und Dichtefunktionaltheorie (DFT). Vereinfachte Kontaktmodelle dienen der qualitativen Untersuchung des Einflusses von Geometrie und Länge der Nanoröhren, sowie von Stärke und Ausdehnung des Kontaktes. Darüber hinaus erlauben solch einfache Modelle mit geringem numerischen Aufwand den Einfluss verschiedener Elektronenstrukturmethoden zu untersuchen. Es zeigt sich, dass die semiempirischen Methoden TB und EHT nicht in der Lage sind die Ergebnisse der DFT quantitativ zu reproduzieren. Ausgehend von diesen Ergebnissen wird ein verbesserter Satz von Hückel-Parametern generiert, der diesen Mangel behebt. Die Untersuchung verschiedener Kontaktmaterialien erfolgt an wohldefinierten atomistischen Metall-CNT-Metall-Strukturen, welche systematisch optimiert werden. Analytische Modelle zur Beschreibung der CNT-Metall-Wechselwirkung werden vorgeschlagen. Darauf aufbauende Berechnungen der elektronischen Transporteigenschaften, können mit Hilfe der verbesserten EHT auf große Systeme ausgedehnt werden. Die Ergebnisse ermöglichen eine Reihung der Metall-CNT-Metall-Systeme hinsichtlich ihrer Leitfähigkeit: Ag ≤ Au < Cu < Pt ≤ Pd < Al. Dies korrespondiert qualitativ mit berechneten Kontaktabständen, Bindungsenergien und Austrittarbeiten der CNTs und Metalle. Zum tieferen Verständnis der Transporteigenschaften erfolgt eine detaillierte Analyse der elektronischen Struktur der Metall-CNT-Metall-Systeme und ihrer Teilsysteme. Dabei erweist sich die energieaufgelöste lokale Zustandsdichte als nützliches Werkzeug zur Visulisierung und zur Charakterisierung der Wechselwirkung zwischen CNT und Metall sowie deren Einfluss auf den Transport.
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Chapitres de livres sur le sujet "DFT and TB"

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Moriarty, John A. "Fundamental Principles in Metals Physics." In Theory and Application of Quantum-Based Interatomic Potentials in Metals and Alloys. Oxford University PressOxford, 2023. http://dx.doi.org/10.1093/oso/9780198822172.003.0002.

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Abstract In this chapter, the underlying fundamental principles in metals physics necessary to develop quantum-based interatomic potentials in subsequent chapters are discussed. Density functional theory (DFT) is reviewed together with guidance from DFT electronic-structure calculations for both prototype simple metals and d-band transition metals. The nearly free electron (NFE) nature of the valence energy bands in simple metals allows a quantum treatment of the cohesive-energy functional within a plane wave basis set and the use of pseudopotential perturbation theory. The narrow d bands of transition series metals can be treated in a tight-binding (TB) representation with localized d basis states and simplified canonical d bands. The full hybrid NFE-TB nature of d-band metals, including sp-d hybridization, can be accommodated in a mixed basis set of plane waves and localized d states through the use of generalized pseudopotential theory, which is developed from a rigorous pseudo-Green’s function approach applied to DFT.
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Sharma, Ramesh, Jisha Annie Abraham, Jagadish Chandra Mahato, Sajad Ahmed Dar, and Vipul Srivastava. "Ferromagnetism in Mn and Fe Doped LuN: A Potential Candidate for Spintronic Application." In Density Functional Theory - Recent Advances, New Perspectives and Applications [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.99774.

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Diluted magnetic semiconductor (DMS) materials have gained a lot of attention in the last decade due to their possible use in spintronics. In this chapter, the effect of transition metal (TM) i.e., Mn and Fe doping on the structural, electronic, magnetic as well as optical properties of pure and doped LuN has been presented from the first principles density functional theory (DFT) calculation with the Perdew-Burke-Ernzerhof-generalized gradient approximation (PBE-GGA) and Tran Blaha modified Becke-Johnson potential (TB-mBJ) as correlation potentials. The predicted Curie temperature is expected to be greater than room temperature in order to better understand the ferromagnetic phase stability, which has also been confirmed through the formation and cohesive energies. The calculated lattice constants for perfect LuN (rock-salt structure) are in good agreement with the experimental values. Interestingly, doping of Mn and Fe on pure LuN displays indirect band gap to a direct band gap with half metallic and metallic character. The detailed analyses combined with density of state calculations support the assignment that the Half-magnetism and magnetism are closely related to the impurity band at the origin of the hybridization of transition states in the Mn-doped LuN. Absorption spectra are blue shifted upon increase in dopant contents and absorption peaks are more pronounced in UV region. The refractive index and dielectric constant show increase in comparison to the pure LuN. According to the Penn’s model, the predicted band gaps and static actual dielectric constants vary. These band gaps are in the near visible and ultraviolet ranges, as well as the Lu0.75TM0.25N (TM = Fe, Mn) materials could be considered possible candidates for the production of optoelectronic, photonic, and spintronic devices in the future.
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Chauhan, Mrs Pooja. "Antitubercular Agents." In Edited Book of Pharmacology-III [According to Latest Syllabus of B. Pharm-VI Semester of Pharmacy Council of India]. Iterative International Publishers, Selfypage Developers Pvt Ltd, 2024. http://dx.doi.org/10.58532/nbennurphch9.

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Antitubercular agents are medications used to treat tuberculosis (TB), a serious infectious disease caused by Mycobacterium tuberculosis. These agents are categorized into first-line and second-line drugs based on their efficacy, toxicity, and role in TB treatment regimens. First-line antitubercular drugs, such as isoniazid, rifampin, pyrazinamide, and ethambutol, are the cornerstone of TB therapy due to their high potency and relative safety. These drugs are usually administered in combination to prevent the development of drug resistance and to effectively eradicate the bacteria. Treatment typically lasts for at least six months, with an initial intensive phase followed by a continuation phase. Second-line drugs, including fluoroquinolones and injectable agents like amikacin, are used when the first-line drugs are ineffective due to resistance or intolerance. The prolonged duration and complexity of TB treatment can lead to challenges with patient adherence, which is critical for preventing the spread of resistant TB strains. Advances in TB research aim to shorten treatment duration, improve drug efficacy, and reduce side effects. Additionally, public health strategies, including Directly Observed Therapy (DOT), are implemented to ensure compliance and successful treatment outcomes.
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"Directly Observed Therapy for the Treatment of Tuberculosis in Baltimore." In 50 Studies Every Doctor Should Know, edited by Michael E. Hochman, Steven D. Hochman, Michael E. Hochman, and Steven D. Hochman. Oxford University Press, 2021. http://dx.doi.org/10.1093/med/9780197533642.003.0050.

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This chapter provides a summary of a landmark study in systems-based practice. Is directly observed therapy (DOT) effective in lowering the rates of tuberculosis (TB) in communities? Starting with this question, it describes the basics of the study, including funding, study location, who was studied, how many patients, study overview, study intervention, follow-up, endpoints, results, and criticism and limitations. The chapter briefly reviews other relevant studies and information, discusses implications, and concludes with a relevant clinical case.
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Costa, João G. Q. "Decision analysis of strategies to deal with non-compliance with TB treatment." In The Economics of Infectious Disease. Oxford University PressOxford, 2006. http://dx.doi.org/10.1093/oso/9780198516217.003.0007.

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Abstract Non-compliance in tuberculosis (TB) treatment is a major cause of concern because it increases the chance of drug resistance and of spreading the disease to others. Non-compliance requires resources that would not be used if the patient had followed the treatment. A patient who abandons the treatment and eventually comes back to start a new treatment has to be enrolled in a longer and more expensive drug scheme. In this way, the resources consumed in the first treatment are wasted and new resources have to be spent on the same patient. One of the reasons why the World Health Organization (WHO) supports DOT (directly observed treatment) is the increase in compliance achieved by this strategy, but DOT has been questioned as not feasible in many contexts.
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Actes de conférences sur le sujet "DFT and TB"

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Balkoulga, Joël Martial, Antoine Béré, Sidiki Zongo, et al. "Comparative Study of the Electronic Properties of Hexagonal and Orthorhombic Structures of RMnO3-Type Perovskites (R=Tb, Dy, Ho and Er) by DFT Calculations." In 2024 IEEE Multi-conference on Natural and Engineering Sciences for Sahel's Sustainable Development (MNE3SD). IEEE, 2024. https://doi.org/10.1109/mne3sd63831.2024.10812115.

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He, Zhixue, Ming Luo, Zhu Yang, Shaohua Yu, and Qi Yang. "Experimental demonstration of 1.45-Tb/s single channel coherent optical DFT-Spread OFDM transmissions." In Asia Communications and Photonics Conference and Exhibition. OSA, 2011. http://dx.doi.org/10.1364/acp.2011.83090y.

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He, Zhixue, Ming Luo, Zhu Yang, Shaohua Yu, and Qi Yang. "Experimental demonstration of 1.45-Tb/s single channel coherent optical DFT-spread OFDM transmissions." In SPIE/OSA/IEEE Asia Communications and Photonics, edited by Xiang Liu. SPIE, 2011. http://dx.doi.org/10.1117/12.905344.

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Li, An, Xi Chen, Guanjun Gao, and William Shieh. "Transmission of 1-Tb/s Unique-word DFT-Spread OFDM Superchannel over 8,000-km SSMF." In Asia Communications and Photonics Conference and Exhibition. OSA, 2011. http://dx.doi.org/10.1364/acp.2011.830929.

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Li, An, Xi Chen, Guanjun Gao, and William Shieh. "Transmission of 1-Tb/s unique-word DFT-spread OFDM superchannel over 8,000-km SSMF." In SPIE/OSA/IEEE Asia Communications and Photonics, edited by Xiang Liu. SPIE, 2011. http://dx.doi.org/10.1117/12.919896.

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Shiri, Daryoush, Yifan Kong, A. Buin, and M. P. Anantram. "Investigation of Strain Effects on the Band-Structure of Si Nanowires using TB and DFT Methods." In 2008 8th IEEE Conference on Nanotechnology (NANO). IEEE, 2008. http://dx.doi.org/10.1109/nano.2008.107.

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Li, An, Xi Chen, Guanjun Gao, Abdullah Al Amin, William Shieh, and Brian S. Krongold. "Transmission of 1.63-Tb/s PDM-16QAM Unique-word DFT-Spread OFDM Signal over 1,010-km SSMF." In Optical Fiber Communication Conference. OSA, 2012. http://dx.doi.org/10.1364/ofc.2012.ow4c.1.

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Li, Chao, Ivan B. Djordjevic, Ming Luo, et al. "Ultra Long-Haul Transmission of a 1-Tb/s LDPC-Coded DFT-S OFDM-8PSK Superchannel over 12,160 km." In Asia Communications and Photonics Conference. OSA, 2013. http://dx.doi.org/10.1364/acp.2013.af2e.2.

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Li, Chao, Ivan B. Djordjevic, Ming Luo, et al. "Ultra Long-Haul Transmission of a 1-Tb/s LDPC-Coded DFT-S OFDM-8PSK Superchannel over 12,160 km." In Asia Communications and Photonics Conference. OSA, 2013. http://dx.doi.org/10.1364/acpc.2013.af2e.2.

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Khuili, Mohamed, Nejma Fazouan, and Hassna Abou El Makarim. "DFT study of physical properties of wurtzite, zinc blende, and rocksalt phases of zinc oxide using GGA and TB-mBJ potential." In 2015 3rd International Renewable and Sustainable Energy Conference (IRSEC). IEEE, 2015. http://dx.doi.org/10.1109/irsec.2015.7454962.

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