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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
311

Quantum Mechanical Calculations on Ring-opening Reactions of Hexachlorophosphazenes

XUE, YUAN 11 August 2021 (has links)
No description available.
312

Kalkulace v podmínkách vybraného podnikatelského subjektu / Costing in the the Condition of the Company

Kubeš, Michal January 2017 (has links)
The master’s thesis is focused to analysis of current conditions of calculations and calculation system of company. The analysis are basis for finding and resolving of problematic sections. The introduction of theoretical basis of cost accounting and calculations is included to first part of the thesis. The second part analyzes of current situation of company and describes relevant processes. The wording of proposals and recommendations for problematic sections, which have been detected by analysis, are included to final part.
313

Analýza vlivu modelu materiálu na mechanické vlastnosti plastových kompozitních dílců / Analysis of the influence of the material model on the mechanical properties of plastic composite parts

Hudeček, Jan January 2018 (has links)
This master thesis deals with computing of mechanicals properties of parts of headlamps. Parts of headlamps are defined with two different material models, linear material model and material model from Moldflow method. The problem is solved by computational modeling with finite element method using Autodesk Moldflow Insight, Ansys 17.2 and Ansys 18.2 with included Moldsim tool. The outputs are calculations of mechanical properties and comparison of both material models.
314

Návrh křídla letounu UAV v kategorii do 600 kg / Wing design of UAV aircraft

Chabada, Martin January 2021 (has links)
The main aim of the this diploma thesis is the wing design of the UAV aircraft, including the appropriate material choice, calculation of the wing load and also strength analysis. Other goals include the design of the location and volume of fuel tanks, as well as the design of wingspan reduction after landing.
315

Strategické řízení nákladů v podniku / Strategic Cost Management in the Company

Němec, Petr January 2021 (has links)
The diploma thesis deals with the issue of strategic cost management in the selected company. The theoretical part contains the division of costs into individual groups, budgeting and cost calculation and acquaintance with the tools of strategic cost management. The practical part focuses on the analysis of the current state of the company and its costs, where a horizontal and vertical analysis of costs and revenues is performed according to data from the company's profit and loss statement. This analysis identifies the key cost items of the company to which the chosen method of strategic cost management is applied in order to significantly reduce these items and thus improve the financial situation of the company.
316

Ab-initio výpočty stability struktur sloučenin niklu a dusíku / Ab-initio calculation of structures´ stability of Ni-N compounds

Šárfy, Pavlína January 2008 (has links)
The present thesis is devoted to ab initio study of electronic structure of nickel nitrides NiN, Ni2N, Ni3N and Ni4N. The results are used to predict the most stable structures for each composition. The total energies and the electronic structures are calculated by means of the pseudopotential method implemented in the Abinit code and by full-potential linearized augmented plane wave (FLAPW) method incorporated in the Wien2K code. For the exchange-correlation energy, both the local density approximation (LDA) and generalized approximation (GGA) are employed. We predicted the face centered cubic structure B3 as the most stable modification of NiN, the primitive tetragonal structure C4 as the most stable modification of Ni2N, the hexagonal structure as the most stable modification of Ni3N (in agreement with experimental data) and the primitive cubic structure as the most stable modification of Ni4N.
317

Logistika v elektrotechnické firmě / Electrotechnic firm logistic

Dvořáková, Ivona January 2010 (has links)
The thesis paies logistics and this firstly from aspects production of the process in theoretic introduction. In the next part of thesis interprets technology projection, capacity calculations and planning. The theory is ending characterization monitored company. The practical part work forms analysis input data prejudicing calculations capacity utilization company and characterization project calculation. The capacitive calculations utilization company for traced period are enclosed at the close this thesis.
318

Návrh a racionalizace pracoviště WORKSHOP v ALPS Electric Czech s.r.o. s přihlédnutím k budoucímu rozvoji společnosti / Project design and rationalization of workshop area in ALPS Electric Czech s.r.o. in line with futher development of the company

Dozbaba, Zdeněk January 2017 (has links)
This thesis describes the workplace workshop in ALPS Electric in Sebranice. It contains a brief description of machinery and theory of technological projecting. For this department is created proposal of the modification flow racks and the transportation. There are budgets for this proposals. The aim of the thesis is to create drawings documentation for the current and future location the workplace workshop.
319

Étude théorique de l'anisotropie magnétique dans des complexes de métaux de transition : application à des complexes mono- et binucléaires de Ni(II) et Co(II) / Theoretical approach to magnetic anisotropy in transition metal complexes : application to Ni(II) and Co(II) mono- and binuclear complexes.

Cahier, Benjamin 27 March 2018 (has links)
Les molécules-aimants sont des complexes moléculaires contenant des ions des métaux de transition ou des lanthanides capables de présenter le phénomène de blocage de l’aimantation en dessous d’une température de blocage Tb. Ce blocage est dû à la présence d’une barrière d’énergie de réorientation de leur aimantation à cause de la présence d’une anisotropie magnétique uniaxiale qui conduit à la présence de deux états stables de l’aimantation.Ces deux états stables sont adressables avec un champ magnétique extérieur. Il est donc,théoriquement, envisageable d’utiliser ces molécules comme unités de base pour le stockage « classique » de l’information.Néanmoins, à cause de la nature quantique des molécules, une relaxation entre les deux états de l’aimantation a lieu à basse température par effet tunnel à travers la barrière d’énergie. Cet effet tunnel a plusieurs causes dont une correspondant à une légère déviation de l’anisotropie magnétique de la situation strictement axiale. Cet effet annule le caractère bistable (classique) des molécules les rendant inutilisables comme bits classiques pour le stockage de l’information. Mais, la présence de l’effet tunnel conduit à une situation particulière à basse température où deux niveaux sont présents séparés par une énergie liée au caractère non axiale (rhombique) de l’aimantation (cas où le spin est entier). Un système à deux niveaux est appelé bit quantique(qubit) et constitue l’unité de base pour la construction d’ordinateurs quantiques si plusieurs conditions sont réunies.Ainsi, pour concevoir des bits classiques ou quantiques, il est indispensable comprendre au niveau microscopique la nature de l’anisotropie magnétique et les facteurs qui l’influencent.Ce travail de thèse est consacré à l’étude théorique de la nature de l’anisotropie magnétique dans des complexes mononucléaires et binucléaires de Ni(II) (S = 1)et de Co(II) (S = 3/2). Des calculs de type ab initio, basés sur la théorie de la fonction d’onde,qui permettent d’extraire les paramètres de l’hamiltonien de spin de l’anisotropie magnétique ont été effectués. Des calculs sur des objets modèles et molécules réelles qui permettent de séparer l’effet des différents paramètres structuraux et électroniques des ligands sur la nature et l’amplitude de l’anisotropie magnétique ont aussi été réalisés.La comparaison entre les calculs sur des complexes modèles et sur des complexes réels permet de rationaliser les propriétés magnétiques des complexes réels et surtout de proposer des stratégies pour la synthèse de nouveaux complexes avec les propriétés souhaitées. L’étude de complexes binucléaires qui peuvent être considérés comme la première étape pour la conception de porte logique quantique a été réalisée. Les calculs sur les complexes binucléaires sont réalisés en fragmentant les molécules en deux espèces mononucléaires. Pour les complexes binucléaires de Ni(II) et Co(II), des calculs de type Density Functional Theory (DFT) pour évaluer l’amplitude et la nature de l’interaction d’échange ont été menés. Pour étudier l’influence d’une perturbation extérieure sur les propriétés magnétiques, l’influence d’un champ électrique placé parallèle et perpendiculaire à l’axe de facile aimantation d’un complexe de Ni(II) a été étudiée. Le champ électrique peut influencer les propriétés d’anisotropie de manière importante ouvrant la possibilité à la manipulation des molécules par cette perturbation. / Single molecule magnets are molecular complexes containing transition metal or lanthanides ions which are able to block their magnetization below a certain blocking temperature Tb. This blocking is caused by an energy barrier separating the two orientations of magnetization leading to two stable magnetization states. These two states can be controlled by an external magnetic field.Therefore, it is theoretically possible to use these molecules as bits which are able to store“classical” information. However, due to the quantum nature of these molecules, the relaxation of magnetization can exist even at low temperatures. This phenomenon is called the quantum tunneling effect and prevents the bistable (classical) behavior of the magnetic properties, as well as their use as classical bits for data strorage.Yet, the quantum tunneling of the magnetization also leads to a particular situation at a low temperature where two levels are separated by an energy related to the non-axial character(rhombic) of the magnetization (when the spinis an integer). Such two-levels system could be used as a quantum bit (qbit) which is the basic unit for quantum information processing. Thus,the design of classical or quantum bits require a precise understanding of magnetic properties and their origin at a microscopic level.The Ph.D work was devoted to the theoretical study of the magnetic anisotropy in mononuclear and binuclear Ni(II) (S=1) and Co(II) (S=3/2) complexes. Ab initio calculations based on the wave function theory were carried out and the spin Hamiltonian parameters were extracted. Model complexes were used to investigate the structural and electronic parameters causing magnetic anisotropy.Calculations were, also, performed on complexes synthesized in the laboratory.Comparison between real and model complexes allowed rationalizing the magnetic properties and imagining new synthesis strategies leading to the desired magnetic properties. Binuclear complexes that can be considered as double qbits and used to build quantum logic gates were also investigated. The calculations were performed by fragmenting the binuclear complexes into two mononuclear units in order to study the local anisotropy of each metal ion.The exchange interaction was investigated using Density Functional theory (DFT). In order to study the influence of an external perturbation on magnetic properties, the magnetic properties of a mononuclear Co(II) complex under an external electric field applied parallel or perpendicular to the axis of easy magnetization were calculated. The application of an electric field can lead to important modifications of magnetic properties. Thereby, offering the possibility to the manipulation of these molecules by external electric fields.
320

Low-rank Approximations in Quantum Transport Simulations

Daniel A. Lemus (5929940) 07 May 2020 (has links)
Quantum-mechanical effects play a major role in the performance of modern electronic devices. In order to predict the behavior of novel devices, quantum effects are often included using Non-Equilibrium Green's Function (NEGF) methods in atomistic device representations. These quantum effects may include realistic inelastic scattering caused by device impurities and phonons. With the inclusion of realistic physical phenomena, the computational load of predictive simulations increases greatly, and a manageable basis through low-rank approximations is desired.<br><br>In this work, low-rank approximations are used to reduce the computational load of atomistic simulations. The benefits of basis reductions on simulation time and peak memory are assessed.<br>The low-rank approximation method is then extended to include more realistic physical effects than those modeled today, including exact calculations of scattering phenomena. The inclusion of these exact calculations are then contrasted to current methods and approximations.

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