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Siebert, Wolfgang Peter. "Alternative electronic packaging concepts for high frequency electronics." Doctoral thesis, Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-223.
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Sergueev, Nikolai. "Electron-phonon interactions in molecular electronic devices." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=102171.
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Over the past several decades, semiconductor electronic devices have been miniaturized following the remarkable "Moores law". If this trend is to continue, devices will reach physical size limit in the not too distance future. There is therefore an urgent need to understand the physics of electronic devices at nano-meter scale, and to predict how such nanoelectronics will work. In nanoelectronics theory, one of the most important and difficult problems concerns electron-phonon interactions under nonequilibrium transport conditions. Calculating phonon spectrum, electron-phonon interaction, and their effects to charge transport for nanoelectronic devices including all atomic microscopic details, is a very difficult and unsolved problem. It is the purpose of this thesis to develop a theoretical formalism and associated numerical tools for solving this problem.In our formalism, we calculate electronic Hamiltonian via density functional theory (DFT) within the nonequilibrium Green's functions (NEGF) which takes care of nonequilibrium transport conditions and open device boundaries for the devices. From the total energy of the device scattering region, we derive the dynamic matrix in analytical form within DFT-NEGF and it gives the vibrational spectrum of the relevant atoms. The vibrational spectrum together with the vibrational eigenvector gives the electron-phonon coupling strength at nonequilibrium for various scattering states. A self-consistent Born approximation (SCBA) allows one to determine the phonon self-energy, the electron Green's function, the electronic density matrix and the electronic Hamiltonian, all self-consistently within equal footing. The main technical development of this work is the DFT-NEGF-SCBA formalism and its associated codes.
A number of important physics issues are studied in this work. We start with a detailed analysis of transport properties of C60 molecular tunnel junction. We find that charge transport is mediated by resonances due to an alignment of the Fermi level of the electrodes and the lowest unoccupied C60 molecular orbital. We then make a first step toward the problem of analyzing phonon modes of the C60 by examining the rotational and the center-of-mass motions by calculating the total energy. We obtain the characteristic frequencies of the libration and the center-of-mass modes, the latter is quantitatively consistent with recent experimental measurements. Next, we developed a DFT-NEGF theory for the general purpose of calculating any vibrational modes in molecular tunnel junctions. We derive an analytical expression for dynamic matrix within the framework of DFT-NEGF. Diagonalizing the dynamic matrix we obtain the vibrational (phonon) spectrum of the device. Using this technique we calculate the vibrational spectrum of benzenedithiolate molecule in a tunnel junction and we investigate electron-phonon coupling under an applied bias voltage during current flow. We find that the electron-phonon coupling strength for this molecular device changes drastically as the bias voltage increases, due to dominant contributions from the center-of-mass vibrational modes of the molecule. Finally, we have investigated the reverse problem, namely the effect of molecular vibrations on the tunneling current. For this purpose we developed the DFT-NEGF-SCBA formalism, and an example is given illustrating the power of this formalism.
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Xu, Shu [Verfasser]. "Graphene Electronics : Device Fabrication and Electronic Transport / Shu Xu." Kiel : Universitätsbibliothek Kiel, 2012. http://d-nb.info/1020496436/34.
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Qian, Xiaofeng. "Electronic structure and transport in molecular and nanoscale electronics." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/44783.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2008.Includes bibliographical references (p. 239-256).
Two approaches based on first-principles method are developed to qualitatively and quantitatively study electronic structure and phase-coherent transport in molecular and nanoscale electronics, where both quantum mechanical nature of electrons and dimensionality of systems play the critical roles in their electronic, magnetic and optical properties. Our first approach is based on Green's function method with ab initio quasiatomic orbitals within Landauer formalism. To efficiently and accurately apply Green's function method, we develop a minimal basis-set of quasiatomic orbitals from plane-wave density functional theory (DFT) results. This minimal basis-set resembles quasi-angular momentum characteristics in solid state systems and it further validates Slater's original idea of linear combinations of atomic orbitals. Based on their ab initio tight-binding matrices, the accuracy, efficiency and stability of our scheme are demonstrated by various examples, including band structure, Fermi surface, Mülliken charge, bond order, and quasiatomic-orbitals-projected band structure and quasiatomic-orbitals-projected Fermi surface. Remarkably these quasiatomic orbitals reveal the symmetry and chemical bonding nature of different molecular, surface and solid systems. With this minimal basis-set, quantum conductance and density of states of coherent electron transport are calculated by Green's function method in the Landauer formalism. Several molecular and nanoscale systems are investigated including atomic wires, benzene dithiolate, phenalenyl dithiolate and carbon nanotube with and without different types of defects.
(cont.) Conductance eigenchannel decomposition, phase-encoded conductance eigenchannel visualization, and local current mapping are applied to achieve deeper understandings of electron transport mechanism, including spin dependence, dimensionality dependence, defect dependence, and quantum loop current induced by time-reversal symmetry breaking. Our second approach naturally arises due to the fact that electron transport is an excited state process. Time-dependent density functional theory (TDDFT) is a fundamental approach to account for dynamical correlations of wave functions and correct band gap in DFT. In our second approach, we mainly focus on the mathematical formulation and algorithm development of TDDFT with ultrasoft pseudopotentials and projector augmented wave method. Calculated optical absorption spectrum gives correct positions and shapes of excitation peaks compared to experimental results and other TDDFT results with norm-conserving pseudopotentials. Our method is further applied to study Fermi electron transmission through benzene dithiolate molecular junction sandwiched by two gold chains. It is first verified that group velocity of Fermi electron in the gold chain obtained by TDDFT agrees with that from band structure theory. Then under rigid band and zero bias approximations, a tiny Fermi electron wave packet from the chain is injected into the molecular junction. Transmission coefficient evaluated after the scattering process is around 5%. This is in agreement with the result from Green's function method. The two methods also show similar characteristic propagation channel. This nice agreement verifies that Green's function approach based on DFT reaches the TDDFT result without dynamical electron correlations in the linear response region.
(cont.) With further development, our quasiatomic orbitals can serve as a minimal basis-set to combine non-equilibrium Green's function and TDDFT together with GW quasi-particle corrections. The unified method will provide a more accurate and efficient way to explore various molecular and nanoscale electronic devices such as chemical sensor, electromechanical device, magnetic memory, and optical electronics.
by Xiaofeng Qian.
Ph.D.
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Rajagopal, Senthil Arun. "SINGLE MOLECULE ELECTRONICS AND NANOFABRICATION OF MOLECULAR ELECTRONIC DEVICES." Miami University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=miami1155330219.
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Kula, Mathias. "Understanding Electron Transport Properties of Molecular Electronic Devices." Doctoral thesis, KTH, Teoretisk kemi, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4500.
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his thesis has been devoted to the study of underlying mechanisms for electron transport in molecular electronic devices. Not only has focus been on describing the elastic and inelastic electron transport processes with a Green's function based scattering theory approach, but also on how to construct computational models that are relevant to experimental systems. The thesis is essentially divided into two parts. While the rst part covers basic assumptions and the elastic transport properties, the second part covers the inelastic transport properties and its applications. It is discussed how di erent experimental approaches may give rise to di erent junction widths and thereby di erences in coupling strength between the bridging molecules and the contacts. This di erence in coupling strength is then directly related to the magnitude of the current that passes through the molecule and may thus explain observed di erences between di erent experiments. Another focus is the role of intermolecular interactions on the current-voltage (I-V) characteristics, where water molecules interacting with functional groups in a set of conjugated molecules are considered. This is interesting from several aspects; many experiments are performed under ambient conditions, which means that water molecules will be present and may interfere with the experiment. Another point is that many measurement are done on self-assembled monolayers, which raises the question of how such a measurement relates to that of a single molecule. By looking at the perturbations caused by the water molecules, one may get an understanding of what impact a neighboring molecule may have. The theoretical predictions show that intermolecular e ects may play a crucial role and is related to the functional groups, which has to be taken into consideration when looking at experimental data. In the second part, the inelastic contribution to the total current is shown to be quite small and its real importance lies in probing the device geometry. Several molecules are studied for which experimental data is available for comparison. It is demonstrated that the IETS is very sensitive to the molecular conformation, contact geometry and junction width. It is also found that some of the spectral features that appear in experiment cannot be attributed to the molecular device, but to the background contributions, which shows how theory may be used to complement experiment. This part concludes with a study of the temperature dependence of the inelastic transport. This is very important not only from a theoretical point of view, but also for the experiments since it gives experimentalists a sense of which temperature ranges they can operate for measuring IETS.QC 20100804. Ändrat titeln från: "Understanding Electron Transport Properties in Molecular Devices" 20100804.
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Geer, Steven Jon. "Electronic properties of bilayer low-dimensional electron systems." Thesis, University of Cambridge, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.619774.
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Zolleis, Kai Rudiger. "Electronic properties of parallel low-dimensional electron systems." Thesis, University of Cambridge, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624494.
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Kula, Mathias. "Understanding electron transport properties in molecular electronic devices /." Stockholm : Bioteknologi, Kungliga Tekniska högskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4500.
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Harland, C. J. "Detector and electronic developments for scanning electron microscopy." Thesis, University of Sussex, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370435.
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Foley, Simon Timothy. "Effects of electron-electron interactions on electronic transport in disordered systems." Thesis, University of Birmingham, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273932.
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Li, Elise Yu-Tzu. "Electronic structure and quantum conductance of molecular and nano electronics." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/65270.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 129-137).
This thesis is dedicated to the application of a large-scale first-principles approach to study the electronic structure and quantum conductance of realistic nanomaterials. Three systems are studied using Landauer formalism, Green's function technique and maximally localized Wannier functions. The main focus of this thesis lies on clarifying the effect of chemical modifications on electron transport at the nanoscale, as well as on predicting and designing new type of molecular and nanoelectronic devices. In the first study, we suggest and investigate a quantum interference effect in the porphyrin family molecules. We show that the transmission through a porphyrin molecule at or near the Fermi level varies by orders of magnitude following hydrogen tautomerization. The switching behavior identified in porphyrins implies new application directions in single molecular devices and molecular-size memory elements. Moving on from single molecules to a larger scale, we study the effect of chemical functionalizations to the transport properties of carbon nanotubes. We propose several covalent functionalization schemes for carbon nanotubes which display switchable on/off conductance in metallic tubes. The switching action is achieved by reversible control of bond-cleavage chemistry in [1+2] cycloadditions, via the 8p 3 8s p 2 rehybridization it induces; this leads to remarkable changes of conductance even at very low degrees of functionalization. Several strategies for real-time control on the conductance of carbon nanotubes are then proposed. Such designer functional groups would allow for the first time direct control of the electrical properties of metallic carbon nanotubes, with extensive applications in nanoscale devices. In the last part of the thesis we address the issue of low electrical conductivity observed in carbon nanotube networks. We characterize intertube tunneling between carbon nanotube junctions with or without a covalent linker, and explore the possibility of improving intertube coupling and enhance electrical tunneling by transition metal adsorptions on CNT surfaces. The strong hybridization between transition metal d orbitals with the CNT [pi] orbitals serves as an excellent electrical bridge for a broken carbon nanotube junction. The binding and coupling between a transition metal atom and sandwiching nanotubes can be even stronger in case of nitrogendoped carbon nanotubes. Our studies suggest a more effective strategy than the current cross-linking methods used in carbon nanotube networks.
by Elise Yu-Tzu Li.
Ph.D.
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ZAMPETTI, EMILIANO. "Future evolution of the electronics nose: technology and electronic design." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2008. http://hdl.handle.net/2108/495.
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Lo scopo principale di questa tesi di Dottorato è uno studio approfondito sul sistema olfattivo artificiale (Naso Elettronico - EN) principalmente dedicato ad applicazioni spaziali. L'ambiente spaziale, piuttosto particolare destinato ad ospitare questo apparecchio ha richiesto particolare attenzione nella progettazione in modo da rispondere in maniera completa a tutte quelle caratteristiche elettriche e meccaniche che sono necessarie per superare tutti i test molto rigorosi di imposti dall'organizzazione internazionale di volo spaziale. La progettazione particolarmente orientata verso l'ottimizzazione generale del sistema, ha prodotto un fattore di qualità generale che, crediamo, influenzerà tutte le applicazioni terrestri nelle quali le prestazioni possono essere di un livello più basso. La strategia di progettazione adottata e seguita nel corso dei tre anni ha considerato i seguenti punti:
a) miniaturizzazione dell'EN precedente (Libra Nose) senza ridurre la flessibilità digitale, includendo tutti i circuiti di interfaccia in un singolo FPGA;
b) miglioramento della parte analogica, in particolare un nuovo disegno degli oscillatori e dell'interfaccia analogica verso i sistemi digitali di conteggio. A tale scopo una cura particolare al livello di progettazione è stata rivolta verso: la riduzione degli spazi occupati e il consumo, usando tensioni di alimentazione nel range che va da 5 V. a 3V. e perfino 1.8 V.: riduzione di tutte le interferenze fra i sensori;
c) l’introduzione di due nuove tecniche che migliorano le prestazioni della coppia sensore-oscillatore. La prima si basa sull'utilizzazione di un singolo oscillatore per tutti i sensori QCM, riducendo lo spazio occupato per i circuiti da N a 1, dove la N è la dimensione della matrice di sensori. L'altra tecnica si basa sull'idea di commutazione di misura di frequenza su ogni oscillatore, uno alla volta accendendo e spegnendo l’oscillatore posto sotto misura. In tal modo si risparmia energia e si ha un rapporto migliore di segnale/disturbo;
d) l'aumento delle prestazioni generali della parte di rilevamento riguardo alla possibilità di aumento della sensibilità verso i composti volatili, attraverso l'introduzione di un riscaldatore integrato sulla superficie del quarzo. L'idea di base considera il fatto che la presenza di un tal riscaldatore contribuisce, una volta attivato, alla riduzione del tempo di desorbimento e di conseguenza, riduce il tempo di recupero nella fase di pulizia. In questo contesto è stato utilizzato un sistema di controllo termico, basato sulla tecnica Δ. Tale sistema può migliorare la ‘tunabilità’ della sensibilità/selettività del sensore chimico (QCM) nei confronti di vari composti volatili. Inoltre, grazie all’utilizzazione del controllo termico sigma-delta, per la prima volta un sensore di flusso è stato integrato su QCM.
Il risultato principale di questa tesi è stata l’accettazione a nome dell'agenzia europea spaziale (ESA) di un Naso Elettronico dedicato spazio che effettivamente è stato utilizzato nella missione di ENEIDE del 2005. Le prove passate per la valutazione dei criteri di costruzione ‘Spazio’ insieme ai risultati ottenuti durante la missione hanno confermato il successo della progettazione fatta nella prima parte di questa tesi. Ulteriori miglioramenti sono stati realizzati nell'ultimo periodo di tesi permettendo la realizzazione di uno strumento in grado di ‘vivere’ molto tempo nelle missioni interplanetarie e cosa di notevole importanza, di essere impiegato in molte delle applicazioni terrestri come: nell’industria, nell’alimentazione, nell’agricoltura, e nella medicina.The principal aim of this PhD thesis is a deep study of an artificial olfaction system (Electronic Nose – EN) mainly dedicated to space applications. The rather particular environment destined to host this apparatus has required a particular attention on many of the design details in order to infer about all those electrical and mechanical features which are necessary to overcome the very stringent stress parameters imposed by the space flight international organization. The request of a particular effort oriented to the overall optimization has produced a general quality factor which, we believe, will influence also all the terrestrial applications where performances may be of a lower level. The adopted strategy which was hold along the past three years has regarded the following points: a) miniaturization of the previous EN (Libra Nose) without reducing the digital flexibility and including all the interface circuits in a single FPGA; b) improvement of the analog part, in particular a new design of the oscillators, and of the analog interface toward the digital part. To this purpose a particular care at the design level has been paid towards: the reduction of occupied spaces, and consumption by using working supply voltages from 5 V. to 3V. and even 1,8 V.: reduction of about all the interferences among sensors; c) introduction of two new techniques improving the performances of the couple QCM sensor and oscillator; one of them is based on the utilization of a single oscillator for all the QCM sensors, reducing the occupied space for the circuits from N to 1, where N is the dimension of the sensor matrix; the other technique concerns the idea of performing the frequency measurement switching on each oscillator one in a time, saving in this way energy and achieving a better signal to noise ratio; d) increasing the overall performances of the sensing part with respect to the capability of increasing the sensitivity towards volatile compounds through the introduction of an integrated heater applied to one of the quartz surfaces. The basic idea considers the fact that the presence of such a heater contributes, once activated, to reduce the desorption time and, as a consequence, to reduce the recovery time in the cleaning phase. In this context by using a control system of the thermal sigma delta (TΔ) type, it has been proven that a better performance on the sensitivity/selectivity tuning with respect to the volatile compound adsorption, can be achieved. Moreover, by means of the utilization of the thermal sigma delta control, for the first time a flow sensor has been embedded on QCM. The main result of this thesis has been the acceptation on behalf of the International Space Agency of a space dedicated EN which was indeed used in the frame of the SOYUZ Mission. The passed space tests together with the results obtained during the Mission have confirmed the outstanding design done in the first part of this thesis. Further improvements have been achieved in the last thesis period allowing the availability of an instrument able to live long time in interplanetary Missions and as an important throughput, to be employed in many of the terrestrial applications regarding the industrial, food and agricultural, medicine, and ambient context.
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Li, Menglong. "Electronic packaging for functional electronic textiles." Thesis, University of Southampton, 2018. https://eprints.soton.ac.uk/428043/.
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An electronic textile (e-textile) is a textile with integrated electronic functionality. It can be used in many areas, for example, clothing, medical, furniture and aerospace applications. The combination of electronics with textiles requires the use of flexible circuit technology, with electronic components mounted on polymer substrates with conductive tracks, to ensure the textile retains as much as possible their normal physical characteristics and feel. E-textiles in wearable applications are subject to human motion activities and as such the integrated electronic components can be vulnerable to different kinds of stresses such as bending. These forces can potentially shear, pull off or damage the components despite the electronic packaging methods used to protect them. Similarly, temperature changes in the environment can induce thermal expansion stresses in the electronic packaging or components which may result in failure. Therefore the need to develop a new reliable electronic packaging method for e-textiles to mitigate these stresses becomes increasingly important. This thesis presents research into a new reliable packaging technique capable of protecting components against twisting, bending or shear stresses. The use of this packaging technique has been evaluated with the ultra-thin die mounted onto thin flexible polymer film strip which contains conductive tracks for electrical interconnections and power supply for electronics. This electronic strip can be subsequently formed into yarns or woven into a textile. The review of electronic packaging techniques for forming electronic connects between the die and substrate such as flip chip bonding, anisotropic adhesives bonding and wire bonding are also included in this thesis. Finite element analysis (FEA) of the electronic strip is also presented. FEA simulations are used to evaluate the mechanical performance of different electronic packaging assemblies. An FEA investigation is presented in the materials and component dimensions in order to maximize the reliability of the packaging method. The three-point bending, shear, tensile and thermal expansion modelling have been simulated and, in the case of shear load and bending, results validated against an experimental evaluation. The shear and bending experimental results show good agreement with the simulation results and verify the simulated optimal thickness of the adhesive layer. Three under-fill adhesives (EP30AO, EP37-3FLF and Epo-Tek 301 2fl), five highly flexible adhesives (MK055, Nu355, Loctite 4860, Loctite 480 and Loctite 4902) and three substrates (Kapton, Mylar and PEEK) have been evaluated and the optimal thickness of each is found. The Kapton substrate, together with the EP37-3FLF adhesive, was identified as the best materials combination, with the optimum under-fill and substrate thickness identified as 0.05 mm. A novel method for packaging electronics using a thermally deformed Kapton was introduced. The design process for the jig that was used to deform the Kapton and the minimum temperature (360 °C) and time (60 Sec) needed to deform the Kapton has been investigated. This is also the first demonstrated method for reliably incorporating electronic circuits in a textile and that can withstand up to 45, 150,000 and 1470 cycles of machine washing, 180 degree twist test and 90 degree bending test respectively. The new ultra-thin silicon chip (0.025 mm thickness) fabrication method has also been introduced in this thesis to increase the flexibility of the electronic packaging method for functional electronic textiles.
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Cao, Hui. "Dynamic Effects on Electron Transport in Molecular Electronic Devices." Doctoral thesis, KTH, Teoretisk kemi, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-12676.
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HTML clipboardIn this thesis, dynamic effects on electron transport in molecular electronic devices are presented. Special attention is paid to the dynamics of atomic motions of bridged molecules, thermal motions of surrounding solvents, and many-body electron correlations in molecular junctions. In the framework of single-body Green’s function, the effect of nuclear motions on electron transport in molecular junctions is introduced on the basis of Born-Oppenheimer approximation. Contributions to electron transport from electron-vibration coupling are investigated from the second derivative of current-voltage characteristics, in which each peak is corresponding to a normal mode of the vibration. The inelastic-tunneling spectrum is thus a useful tool in probing the molecular conformations in molecular junctions. By taking account of the many-body interaction between electrons in the scattering region, both time-independent and time-dependent many-body Green’s function formula based on timedependent density functional theory have been developed, in which the concept of state of the system is used to provide insight into the correlation effect on electron transport in molecular devices. An effective approach that combines molecular dynamics simulations and first principles calculations has also been developed to study the statistical behavior of electron transport in electro-chemically gated molecular junctions. The effect of thermal motions of polar water molecules on electron transport at different temperatures has been found to be closely related to the temperature-dependent dynamical hydrogen bond network.QC20100630
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Sze, Kong Hung. "Electronic excitation of polyatomic molecules by fast electron impact." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/29302.
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High resolution electron energy loss spectroscopy has been used to examine the inner-shell and valence-shell electronic excitation of a number of polyatomic molecules, including SF₆, SeF₆, TeF₆, ClF₃, C₂H₃F, C₂H₃Cl, C₂H₃Br, C₂H₃I, Ni(CO)₄, (CH₃)₂SO and SO₂. The inner-shell and valence-shell electron energy loss spectra (ISEELS and VSEELS) were measured under low momentum transfer conditions with impact energy in the range of 1-3.7 keV and 0° scattering angle. Under these conditions the spectra are dominated by electric dipole-allowed transitions. The ISEELS spectra include all accessible core excitations of these molecules below 1000 eV equivalent photon energy. A number of specific investigations have been performed in order to extend present understanding of the physical nature of electronic excitation phenomena, in particular those involving inner-shell electrons. In addition the present work illustrates new applications of ISEELS to the study of chemical phenomena.
In the investigation of (Coulombic) potential barrier effects in the "cage" molecules SF₆, SeF₆, TeF₆ and ClF₃, f-type continuum shape resonances are observed for the first time in the spectra of TeF₆ and they show very different spectral behavior from the d-type continuum shape resonances observed in the spectra of SF₆ and SeF₆. Consideration of both the ISEELS and VSEELS spectra indicates that there is a weakening of the potential barrier in going through the series from SF₆ to SeF₆ to TeF₆. The Coulombic potential barrier model provides an extremely satisfactory understanding of (a) the co-existence of intense continuum shape resonances and intense Rydberg transitions plus direct ionization continuum; and (b) the number and symmetry of continuum shape resonances observed in the ISEELS spectra of ClF₃. The physical significance of Coulombic potential barrier effects is further convincingly demonstrated by a comparison of the "central atom" inner-shell spectra of SF₆, ClF₃ and HCl.
In contrast to earlier work, the present comparative study of the He(I) and He(II) photoelectron spectra and the VSEELS excitation spectra of the monohaloethylenes (i.e. C₂H₃X; X = F, Cl, Br and I) suggests that the HOMO orbital in C₂H₃I is predominantly of iodine 5p[sub ⊥](out-of-plane) character rather than of π character whereas the reverse situation applies to the HOMO orbitals of C₂H₃F, C₂H₃Cl and C₂H₃Br. Based on a term value correlation analysis, substitutional effects are found to be most prominent in the σ* -type orbitals, while the π* and Rydberg orbitals are less influenced. Linear correlations between the C-X bond strength and the term values for both inner-shell and valence-shell transitions to the σ* (CX) orbital are also observed.
The ISEELS and VSEELS spectra of Ni(CO)₄ are compared with the
corresponding spectra in free CO. The C and O Is spectra of these two molecules show
some notable similarities despite the very different manifold of final states available. In
particular the inner-shell spectra of both molecules exhibit intense ls → π* and ls → σ* transitions. High resolution ISEELS has been used to obtain vibrational resolved C Is spectra of Ni(CO)₄ and free CO. The implications and possibilities of studying dπ →pπ back-bonding in transition metal carbonyl complexes by high resolution ISEELS spectroscopy are discussed.
The inner-shell (S 2s, 2p, C Is) excitations of (CH₃)₂SO (DMSO) measured by ISEELS are compared with synchrotron radiation studies of the S Is photoabsorption spectrum. The pre-edge regions of these spectra are interpreted as excitations to common manifolds of virtual valence and Rydberg orbitals. A linear correlation between the S-C bond lengths and the term values of S 2p[sub 3/2] → σ* (S-C) transitions is demonstrated for DMSO and a number of other sulfur compounds.
The S 2p, 2s and O Is ISEELS spectra of SO₂ as well as the S ls photoabsorption spectrum are compared with and assigned according to the results of multichannel quantum defect theory calculations. The calculated energies and oscillator strengths of spectral features in these spectral regions are generally in good quantitative agreement with the measurements.Science, Faculty of
Chemistry, Department of
Graduate
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Li, Yuesong. "Electronic structure and spectra of few-electron quantum dots." Diss., Available online, Georgia Institute of Technology, 2007, 2007. http://etd.gatech.edu/theses/available/etd-05172007-110916/.
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Thesis (Ph. D.)--Physics, Georgia Institute of Technology, 2008.Minqiang Li, Committee Member ; Constantine Yannouleas, Committee Member ; Michael Pustilnik, Committee Member ; Mei-Yin Chou, Committee Member ; Uzi Landman, Committee Member.
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Zhou, Wen. "Electronic structure and single electron reactivity in organochromium complexes." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/44188.
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Galda, Alexey. "Electronic properties of Luttinger Liquid with electron-phonon interaction." Thesis, University of Birmingham, 2013. http://etheses.bham.ac.uk//id/eprint/4293/.
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This thesis addresses a theoretical study of the problem of a single impurity embedded in a one-dimensional system of interacting electrons in presence of electron-phonon coupling. First we consider a system with a featureless point-like potential impurity, followed by the case of a resonant level hybridised with a Luttinger Liquid. The stress is made on a more fundamental problem of a featureless scatterer, for which two opposite limits in the impurity strength are considered: a weak scatterer and a weak link. We have found that, regardless of the transmission properties of phonons through the impurity, the scaling dimensions of the conductance in these limits obey the duality condition, \( \triangle_{WS}\) \( \triangle_{WL}\) = 1, known for the Luttinger Liquid in the absence of phonons. However, in the case when the strength of phonon scattering is correlated with electron scattering by the impurity, we find a nontrivial phase diagram with up to three fixed points and a possibility of a metal-insulator transition. We also consider the case of a weakly interacting electron-phonon system in the presence of a single impurity of an arbitrary scattering potential. In the problem of a resonant level attached to the Luttinger Liquid we show that the electron-phonon coupling significantly modifies the effective energy-dependent width of the resonant level in two different geometries, corresponding to the resonant and anti-resonant transmission in the Fermi gas.
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Bowman, John V. "Transport in a confined two-dimensional electron gas with longitudinal potential variations." Virtual Press, 1995. http://liblink.bsu.edu/uhtbin/catkey/958798.
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Since the discovery of conductance quantization within a nanostnucture, investigations have sought out causes to conductance fluctuations beyond the established plateaus. The focus of this work is to show the fundamental effects upon conductance due to longitudinal potentials and double quantum boxes when confined by hardwall boundaries. A theoretical model based upon a tight-binding recursive tureen's function methodology was modified to incorporate potential barrier variations. A qualitative evaluation, as well as, explanation of the model's results and limitations is discussed.Department of Physics and Astronomy
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SALEH, MOUSTFA. "Embedded Electronic Systems for Electronic Skin Applications." Doctoral thesis, Università degli studi di Genova, 2021. http://hdl.handle.net/11567/1039846.
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The advances in sensor devices are potentially providing new solutions to many applications including prosthetics and robotics. Endowing upper limb prosthesis with tactile sensors (electronic/sensitive skin) can be used to provide tactile sensory feedback to the amputees. In this regard, the prosthetic device is meant to be equipped with tactile sensing system allowing the user limb to receive tactile feedback about objects and contact surfaces. Thus, embedding tactile sensing system is required for wearable sensors that should cover wide areas of the prosthetics. However, embedding sensing system involves set of challenges in terms of power consumption, data processing, real-time response and design scalability (e-skin may include large number of tactile sensors). The tactile sensing system is constituted of: (i) a tactile sensor array, (ii) an interface electronic circuit, (iii) an embedded processing unit, and (iv) a communication interface to transmit tactile data. The objective of the thesis is to develop an efficient embedded tactile sensing system targeting e-skin application (e.g. prosthetic) by: 1) developing a low power and miniaturized interface electronics circuit, operating in real-time; 2) proposing an efficient algorithm for embedded tactile data processing, affecting the system time latency and power consumption; 3) implementing an efficient communication channel/interface, suitable for large amount of data generated from large number of sensors.
Most of the interface electronics for tactile sensing system proposed in the literature are composed of signal conditioning and commercial data acquisition devices (i.e. DAQ). However, these devices are bulky (PC-based) and thus not suitable for portable prosthetics from the size, power consumption and scalability point of view. Regarding the tactile data processing, some works have exploited machine learning methods for extracting meaningful information from tactile data. However, embedding these algorithms poses some challenges because of 1) the high amount of data to be processed significantly affecting the real time functionality, and 2) the complex processing tasks imposing burden in terms of power consumption. On the other hand, the literature shows lack in studies addressing data transfer in tactile sensing system. Thus, dealing with large number of sensors will pose challenges on the communication bandwidth and reliability. Therefore, this thesis exploits three approaches:
1) Developing a low power and miniaturized Interface Electronics (IE), capable of interfacing and acquiring signals from large number of tactile sensors in real-time. We developed a portable IE system based on a low power arm microcontroller and a DDC232 A/D converter, that handles an array of 32 tactile sensors. Upon touch applied to the sensors, the IE acquires and pre-process the sensor signals at low power consumption achieving a battery lifetime of about 22 hours. Then we assessed the functionality of the IE by carrying out Electrical and electromechanical characterization experiments to monitor the response of the interface electronics with PVDF-based piezoelectric sensors. The results of electrical and
electromechanical tests validate the correct functionality of the proposed system. In addition, we implemented filtering methods on the IE that reduced the effect of noise in the system. Furthermore, we evaluated our proposed IE by integrating it in tactile sensory feedback system, showing effective deliver of tactile data to the user. The proposed system overcomes similar state of art solutions dealing with higher number of input channels and maintaining real time functionality.
2) Optimizing and implementing a tensorial-based machine learning algorithm for touch modality classification on embedded Zynq System-on-chip (SoC). The algorithm is based on Support Vector Machine classifier to discriminate between three input touch modality classes “brushing”, “rolling” and “sliding”. We introduced an efficient algorithm minimizing the hardware implementation complexity in terms of number of operations and memory storage which directly affect time latency and power consumption. With respect to the original algorithm, the proposed approach – implemented on Zynq SoC – achieved reduction in the number of operations per inference from 545 M-ops to 18 M-ops and the memory storage from 52.2 KB to 1.7 KB. Moreover, the proposed method speeds up the inference time by a factor of 43× at a cost of only 2% loss in accuracy, enabling the algorithm to run on embedded processing unit and to extract tactile information in real-time.
3) Implementing a robust and efficient data transfer channel to transfer aggregated data at high transmission data rate and low power consumption. In this approach, we proposed and demonstrated a tactile sensory feedback system based on an optical communication link for prosthetic applications. The optical link features a low power and wide transmission bandwidth, which makes the feedback system suitable for large number of tactile sensors. The low power transmission is due to the employed UWB-based optical modulation. We implemented a system prototype, consisting of digital transmitter and receiver boards and acquisition circuits to interface 32 piezoelectric sensors. Then we evaluated the system performance by measuring, processing and transmitting data of the 32 piezoelectric sensors at 100 Mbps data rate through the optical link, at 50 pJ/bit communication energy consumption. Experimental results have validated the functionality and demonstrated the real time operation of the proposed sensory feedback system.
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Zhu, Zhineng. "Low Noise Offset Operational Amplifier for Nanopore-based Gene Sequencer." Fogler Library, University of Maine, 2007. http://www.library.umaine.edu/theses/pdf/ZhuZ2007.pdf.
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Flanagan, Beavan. "Turning over, for 13 instruments, piano, electronic microtonal piano and electronics." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=116997.
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Turning Over is a 13-minute composition for 13 instruments, piano, electronic piano and pre-recorded electronics. A strong emphasis on harmony, representing the result of two years of research into various intonation theories of the 17th, 18th and 20th centuries, is reflected in the subtle variations in intonation between the equal-tempered acoustic instruments and the just-intonation tuning of the electronics as well as the electronic piano. The musical discourse reflects philosophical concerns regarding the concept of essence in music and its illusive nature – this translates into a musical form that is in a constant state of transformation.Turning Over ('ressasser') est une composition pour 13 instruments, piano, piano électronique et sons électroniques d'une durée de 13 minutes. Un fort accent sur l'harmonie, qui est le résultat de deux années de recherche sur les théories du tempérament musical du 17e, 18e et 20e siècle, est reflété dans les variations subtiles de tempérament entre les instruments acoustiques et les éléments électroniques. Le discours musical reflète des préoccupations philosophiques concernant le concept de l'essence dans la musique et de sa nature illusoire – ceci se traduit dans une forme musicale qui est toujours en état de transformation.
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Georgiev, Vihar Petkov. "Electronic structure/function relationships in metal nanowires : components for molecular electronics." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:594d870f-feef-474b-98e9-5f09505908a3.
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The dramatic expansion of the electronics industry over the past 40 years has been based on the progressive reduction in size of the silicon-based semiconductor components of integrated circuits. The miniaturisation of semi-conductor circuits cannot, however, continue indefinitely, and we are rapidly approaching the stage where quantum effects will prevent further dramatic improvements in computer performance using existing technology. As a result, the field of molecular electronics, which seeks to identify and develop much smaller molecular analogues of the transistors that make up integrated circuits, has expanded rapidly over the past few years. Recent studies suggested that extended metal atom chains (EMAC) may have many potential applications in molecular electronics, but it is clear that this potential can only be realised if we establish a link between the fundamental electronic properties of these systems and the transport of electrons. For this reason the ultimate goal of this thesis is to relate the electronic structure of extended metal chains to their electron transport properties. We address the problem using non-equilibrium Green’s function, in conjugation with density functional theory. In the results sections of this thesis we present calculations on tricobalt, trichromium and trinickel chains. Our data suggested that in the trimetal chains, the dominant electron transport channel is the σ manifold, while the π systems establish the contact with the electrodes. The implication of this is that even when the highly polarized π channels are strongly rehybridised by the applied electric field, current flow is not affected. In the trichromium systems we find that the distortion of the chain away from the symmetric equilibrium structure does not perturb the current flow but rather enhances it. Our rather counter intuitive conclusion is therefore that ‘broken wires’ (highly unsymmetric) are more efficient conductors than their symmetric counterparts. We have performed calculation on longer penta- and heptacobalt structures chains to establish the extent to which longer structures attenuate the conductance. Our calculations show significant oscillations of the conductance due to development of a one-dimensional band structure about the Fermi level. The evolution of the electron transport properties in cobalt chains with different length is a complex one, but it is clear that narrowing the band gap in longer chains makes it increasingly likely that the Fermi level will be in resonance with one or more of the orbitals of the extended metal atom chain.
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Ivarsson, Niklas. "Electronic Scoring System : An Electronic & Mathematical Approach." Thesis, Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-43314.
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This dissertation describes a project to create an electronic shooting system made of simple and inexpensive components, namely a Raspberry Pi computer and sound detectors. The initial goals are to create a system that can be used with an acceptable precision. Secondly a performance analysis will be carried out to determine the precision that can be obtained using these components. The project was developed into three modules: back-end, Cloud and front-end. The back-end is used to gather the information of a projectile on the target, calculate the coordinates and send it to the Cloud. The Cloud acts as the interface between the back-end with the front-end. Lastly the front-end is the Viewer Client that presents the score and positon at which the projectile hit the target. After developing all the components and applications there was a functional system, but not a reliable system. This combination of Raspberry Pi and sound detectors were not good enough to obtain the precision required for the system to work as an electronic scoring system.
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Alghamdi, Abdulhadi M. S. "Electronic commerce with particular reference to electronic contracts." Thesis, University of Aberdeen, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275068.
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This thesis analyses legal issues related to evidence and contract laws in the context of electronic commerce. Electronic commerce raises a number of legal problems such as the need for authentication, liabilities, whether electronic records are admissible as evidence and whether electronic transmissions are considered writing where writing is required. Many legal systems have faced or will face some questions, such as whether electronic evidence is inadmissible only in the ground of being created or stored electronically? Should the law of evidence be reformed in order to meet the new technologies? It is questionable whether electronic communications and records can or should meet the legal requirements of "writing" and "signature". Do electronic and digital signatures satisfy the legal requirements? It has been argued that it is not logical and reasonable to apply legal requirements that have been constituted in the ground of paper-based communication on electronic communication. Electronic contracts raise some legal issues, including whether the contract must be in a particular form or authenticated; when the message is sent and received; whether it is received in the same form as it is sent; validity, time and place of communication; cross-offers and battle of forms issues. All these issues are considered from UK common law point of view and according to CISG, UNIDROIT Principles, PECL, UNCITRAL Model Laws and the Uniform Commercial Code. Electronic contracts involve consideration whether a computer can properly be used to enter into a contractual relationship, to which existing rules on contract negotiation may need to be developed to suit formation of contracts by means of computer and telecommunications and whether old rules are appropriate today. This study examines other legal problems relating to contracts formed on the Internet, including the use of electronic agents, enforceability of mass-market licences, electronic payments and choice of law and jurisdiction issues.
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Taher, Elmasly Saadeldin Elamin. "Electronic evaluation of organic semiconductors towards electronic devices." Thesis, University of Strathclyde, 2013. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=22541.
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Organic p-conjugated macromolecules, (polymers and oligomers) are an important class of semiconductor which are used in applications such as: field effect transistors, photovoltaics, organic light emitting diodes and electrochromic devices. The p-conjugated systems have tuneable band gaps (Eg) and redox properties, whilst offering the potential for flexibility and low cost. In this thesis, the macromolecular compounds and their low molecular weight precursors were characterised by determining their electrochemical and optical properties which were measured using a series of techniques such as: cyclic voltammetry; UV/vis spectroscopy; emission spectroscopy; spectroelectrochemistry; Raman spectroscopy and thermal analyses. Chapter 2 Presents thiophene copolymers with electroactive nitrogen heterocycles. In section 1, a series of monomers containing heteropentalene mesomeric betaine derivatives were characterized. In particular the 3,4-ethylenedioxythiophene (EDOT) derivative (9) was successfully electropolymerised, yielding a polymer with small optical and electrochemical Eg. In Section 2 the characterisation of EDTT, 3-hexylthiophene and EDOT units (17, 18 and 19 respectively) along with their benzothiadiazole (BT) copolymers are shown. Interesting changes in planarity were observed between the PEDOT and PEDTT compounds. Section 3 and 4 produced many EDOT/thiophene derivatives from phenanthroline and [Ru(bpy)2]) as the core unit. (20-26) All polymers exhibited lower electrochemical Eg when compared to their monomers. Compound 26 was polymerised with high oxidative stability to anodic conditions, however, monomer 25 did not polymerise, due to the domination of the strong RuII/RuIII oxidation process. Section 5 shows bis-EDOT pyridine based monomers (27 and 28). Monomer 28 displayed significant effect of the intramolecular charge transfer (ICT) process and lower electrochemical Eg. Three are new compounds 29, 30 and 31 in the section 6, BODIPY cores with two EDOT, thiophene and EDTT units respectively. When all were compared, Compound 29 showed red shift in the absorption spectra, due to stronger electron donating effect of EDOT. Chapter 3: In section 1 the optical and electrochemical properties of three oligofluorene substituted DPP macromolecules (32, 33, 34) and the core precursors (35, 36, 37 and 38) were investigated. The absorption spectra of all compounds in CH2Cl2 revealed two peaks attributed to p-p* transition of quaterfluorene arms and the absorption of DPP core. Compound 33 exhibited a higher LUMO level compared to the other compounds, which was attributed to the effects of the hexyldecyl and phenyl groups. Section 2 describes six new C3-symmetric compounds containing BT units and truxene core (41-46). The UV-absorption spectra of compounds 41-45, reveal an ICT band which is hypsochromically shifted in the case of compound 41 and is not resolved for compound 46. Compounds 41-44 exhibited a good agreement between electrochemical and optical Eg, while a significant difference between those of compound 46 indicates the poor HOMO-LUMO overlap. Chapter 4 A novel processing methodology was used to fabricate multi-layer organic electronic devices by employing electropolymerisation to form a PEDOT/PEDTT bi-layer. The fabricated device did not exhibit any distinctive photo-response when it was assessed in a diode configuration. This was due to inefficient charge separation at the donor- acceptor interface.
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Prance, Jonathan Robert. "Cooling an electron gas using quantum dot based electronic refrigeration." Thesis, University of Cambridge, 2009. https://www.repository.cam.ac.uk/handle/1810/244593.
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Studies of two-dimensional electron gases (2DEGs) in semiconductors form an active and productive field of condensed matter physics research. As well as having interesting inherent properties, they are used as the foundation for constructing various nano-scale electronic devices, such as quantum wires and quantum dots. Conventionally, low temperature measurements of 2DEGs are made by cooling the sample to 1.5 K with liquid Helium-4, to 300 mK with liquid Helium-3, or even down to a few mK using a dilution refrigerator. However, at lower temperatures the electron gas becomes increasingly decoupled from the lattice in which it resides. Below ~ 1 K the coupling can be weak enough for the electron gas to be significantly elevated in temperature due to parasitic heating. In this thesis we present the experimental and theoretical investigation of a refrigeration scheme that has the potential to cool 2DEGs below the temperatures currently available. Cooling to ever lower temperatures would be beneficial for studying fragile fractional quantum Hall states, non-Fermi-liquid behaviour in bilayer 2DEGs, or interactions like the Kondo effect that occur between quantum dots and 2DEGs. The scheme we investigate is called the Quantum Dot Refrigerator (or QDR) and is based upon the energy selective transport of electrons through the singleparticle states of quantum dots. By using a pair of dots, both hot electrons and hot holes can be selectively removed from an otherwise electrically isolated 2DEG. The result is a net current that continuously removes heat. This type of refrigerator is best suited to be used in conjunction with a dilution fridge or Helium-3 system to provide a final stage of cooling. The scheme was first investigated theoretically in 1993 by Edwards et al. but, to our knowledge, has never before been demonstrated experimentally. We detail the fabrication and measurement of a QDR device that is designed to cool an isolated 6 µm2 2DEG. In order to interpret the behaviour of the device, a model was developed to take account of electrostatic interactions between the components of the system (the quantum dots and the isolated 2DEG). Electrostatic interactions were found to be significant for our design, but were neglected in previous work. Our model predicts that their presence complicates, but does not invalidate, the principle of operation of a QDR. By comparing measurements of the current through the QDR with predictions of the model, we show that the observed behaviour is consistent with cooling of the isolated 2DEG by up to 100 mK at ambient temperatures around 250 mK. Although these temperatures are well within the reach of conventional refrigeration techniques, the results are a compelling proof-of-concept demonstration that the QDR principle is sound and can achieve significant refrigeration in the right conditions. Finally, we discuss future directions for improving QDR performance and characterisation, and for lowering the achievable base temperature. We also suggest how QDRs could be used to provide cold reservoirs for a nano-scale electronic device, and explore the limitations that would apply to such an experiment.
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Al, Sawi A. N. "Study of the electronic structure of InSb by electron spectroscopy." Thesis, University of Liverpool, 2017. http://livrepository.liverpool.ac.uk/3007631/.
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Vistoli, Lorenzo. "Topological and electronic properties of electron-doped manganite thin films." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS113.
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Les couches minces d'oxyde présentent un large éventail de phénomènes physiques et riches diagrammes de phase, ajustables par l'ingénierie des déformations et des interfaces. Le CaMnO3, en particulier, est extrêmement sensible au dopage et aux contraintes d’épitaxie et, lorsqu'il est élaboré sous compression, il passe d'un état isolant et antiferromagnétique à un état métallique et faiblement ferromagnétique à seulement 2% de dopage au Ce.Nous avons utilisé une combinaison de spectroscopie de photoémission résolue en angle, de magnétotransport et de théorie de la fonctionnelle de la densité pour étudier les propriétés électroniques de ce matériau. Nous avons observé l'existence de deux porteurs de charge distincts, les électrons légers et les polarons lourds, dont la nature diffère en raison de leur couplage radicalement différent aux phonons. Nous attribuons ces différences à un remplissage relatif différent de la bande en raison des corrélations, qui améliorent considérablement le couplage aux phonons de la bande des polarons lourds. Les expériences de magnétotransport révèlent que la bande polaire domine le transport malgré sa mobilité réduite.La compression épitaxiale donne également lieu à une forte anisotropie magnétique qui stabilise des bulles magnétiques et s’accompagnent d’un effet Hall topologique. Cela suggère que ces bulles ont un caractère topologique. L'effet Hall topologique diverge lorsque la manganite s'approche de la transition métal-isolant à faible dopage. Nous avons utilisé une théorie récemment développée pour interpréter ce comportement, et nous concluons que des corrélations peuvent entrer en jeu, augmentant la masse effective des porteurs et par conséquent l'effet Hall topologique.Comme cette manganite est très sensible aux changements de densités de porteurs, nous avons développé des transistors à effet de champ ferroélectriques BiFeO3/(Ca,Ce)MnO3. Lors de la commutation de la polarisation ferroélectrique de la couche supérieure de BiFeO3, nous n'avons pu observer de changement notable dans les propriétés des couches de manganite sous-jacentes. Nous avons utilisé la microscopie électronique en transmission pour étudier les propriétés de ces bicouches avec une résolution atomique, et nous avons observé que l'épinglage de polarisation à l’interface BiFeO3/(Ca,Ce)MnO3 empêche une commutation complète de la polarisation et réduit ainsi la capacité opérationnelle de ces dispositifs. Néanmoins, nous avons pu détecter l’influence de la polarisation ferroélectrique sur les propriétés électroniques de la manganite à l’échelle atomiqueOxide thin films feature a wide range of physical phenomena and rich phase diagrams tunable by strain and interface engineering. CaMnO3, in particular, is extremely sensitive to both doping and strain and, when grown with compressive strain, transitions from an insulating and antiferromagnetic state to a metallic and weakly ferromagnetic state at only 2% Ce doping.We used a combination of angle-resolved photoemission spectroscopy, magnetotransport, and density functional theory to study the electronic properties of this material. We observed the existence of two separate charge carriers, light electrons and heavy polarons, whose physical nature differs because of drastically different couplings to phonons. We ascribe these differences to a different relative band filling due to correlations, which enhance greatly the coupling to phonons of the heavy polarons band. Magnetotransport experiments reveal that the polaron band dominates transport despite its lower mobility.Compressive strain also gives rise to a strong magnetic anisotropy which stabilizes magnetic bubbles that accompany a topological Hall effect. This suggests that these bubbles have topological character, i.e. are skyrmion bubbles. The topological Hall effect diverges as the manganite approaches the metal-insulator transition at low dopings. We used a recently developed theory in order to interpret this behavior, and we conclude that correlations may come into play, enhancing the effective mass of the carriers, and in turn the topological Hall effect.As this manganite is highly sensitive to changes in doping and carrier density, we grew BiFeO3/(Ca,Ce)MnO3 ferroelectric field-effect transistors. Upon switching the ferroelectric polarization of the BiFeO3 top layer, we could not observe any sizable changes in the properties of the underlying manganite layers. We used transmission electron microscopy to study the properties of these bilayers with an atomic resolution, and we observed that polarization pinning at the BiFeO3/(Ca,Ce)MnO3 impedes a complete switch of the polarization and so reduces the operational capabilities of these devices. Nevertheless, we could detect modifications of the electronic properties of the manganite induced by polarization reversal at the atomic scale
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Hameluck, Jeff. "Electronic sculpting." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ35836.pdf.
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Poyton, David Andrew. "Electronic contracts." Thesis, Aberystwyth University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.440163.
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Keck, Andrew G. "Electronic discovery." Thesis, Utica College, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10101099.
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Cyber incidents continue to increase across the entire globe. The increase in security threats requires organizations to rethink strategies and policies continually fortifying against known and unknown threats. Cyber incident policies and response plans range from non-existent to hundreds of pages in length. A policy may include sections discussing roles and responsibility, incident detection, escalation, and many additional categories, and often discuss the collection and preservation of forensic evidence. Policies briefly address, in many cases, the proper collection of evidence; however, the written regulation concerning the potential liabilities, the risks associated with current and future litigation, and the legal consequences to a cyber incident remains sparse. The desired outcome of this paper is to enlighten the reader through identification of the risks, the potential pitfalls, and steps to policy development pertaining to the handling of electronic evidence, with a cross examination of overlapping sectors between forensics, electronic discovery, and cyber security.
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Denisenko, Y., and L. M. Chuchilina. "Electronic money." Thesis, Вид-во СумДУ, 2009. http://essuir.sumdu.edu.ua/handle/123456789/17048.
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Modern, quickly developing world impossible to present without electronic money. Quite soon they will become integral part of our life. Electronic money is really incredible invention of humanity.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/17048
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Sartawi, M. "Electronic business." Thesis, Вид-во СумДУ, 2007. http://essuir.sumdu.edu.ua/handle/123456789/17436.
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Золотова, Світлана Григорівна, Светлана Григорьевна Золотова, Svitlana Hryhorivna Zolotova, and D. V. Shapko. "Electronic paper." Thesis, Видавництво СумДУ, 2010. http://essuir.sumdu.edu.ua/handle/123456789/18406.
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Kraft, Martin. "Electronic Justice." Master's thesis, Vysoká škola ekonomická v Praze, 2010. http://www.nusl.cz/ntk/nusl-16696.
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The thesis analyzes the e-Justice projects in the Czech Republic. It describes possibilities of application of individual projects, evaluates the status of their development and their potential future evolution. The thesis also analyzes the economic aspects of selected projects as well as discusses the technological aspects of some technologically advanced projects. On the basis of the analysis of present situation and description of e-Justice issues the contribution of this process for the Czech judiciary system as well as the public government or private persons will be described. The main contribution of this thesis is to objectively evaluate the effects of judiciary digitization for the Czech public administration information systems and related areas.
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Jäckel, Frank. "Self assembly and electronic properties of conjugated molecules: towards mono molecular electronics." [S.l. : s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=975579010.
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Unge, Mikael. "Molecular Electronics : A Theoretical Study of Electronic Structure of Bulk and Interfaces." Doctoral thesis, Linköpings universitet, Beräkningsfysik, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-6938.
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This thesis deals with theoretical studies of the electronic structure of molecules used in the context of molecular electronics. Both studies with model Hamiltonians and first principle calculations have been performed. The materials studied include molecular crystals of pentacene and DNA, which are used as active material in field-effect transistors and as tentative molecular wires, respectively. The molecular magnet compound TCNE and surface modification by means of chemisorption of TDAE on gold are also studied. Molecular crystals of pentacene are reported to have the highest field-effect mobility values for organic thin film field-effect transistors. The conduction process in field-effect transistors applications occurs in a single layer of the molecular crystal. Hence, in studies of transport properties molecular crystals of pentacene can be considered as a two dimensional system. An open question of these system is if the charge transport is bandlike or if as a result of disorder is a hopping process. We address this question in two of the included papers, paper I and paper II. The conducting properties of DNA are of interest for a broad scientific community. Biologist for understanding of oxidatively damaged DNA and physicist and the electronics community for use as a molecular wire. Some reports on the subject classifies DNA as a conductor while other report insulating behavior. The outcome of the investigations are heavily dependent on the type of DNA being studied, clearly there is a big difference between the natural and more or less random sequence in, e.g., λ-DNA and the highly ordered syntethic poly(G)-poly(C) DNA. It has been suggested that long-range correlation would yield delocalized states, i.e., bandlike transport, in natural DNA, especially in the human chromosome 22. In paper III we show that this is not the case. In general our results show that DNA containing an approximately equal amount of the four basis is an insulator in a static picture. An emerging research field is spintronics. In spintronic devices the spin of the charge carrier is as important as the charge. One can envision a device where spin alone is the carrier of information. In realizing spintronic devices, materials that are both magnetic and semiconducting are needed. Systems that exhibit both these properties are organic-based magnets. In paper IV the electronic structure of the molecular magnet compound TCNE is studied, both experimentally and theoretically. The injection of carriers from metal contacts to organic semiconductors is central to the performance of organic based devices. The interface between the metal contact and the organic material has been pointed out to be one of the device parameters that most significantly influences the device performance. This relates to the process of injection of charge carriers in to the organic material. In some contact and organic material combinations the energy barrier for charge injection can be very high. The barrier can be reduced by modify the interface dipole, this is achieved by a monolayer of adsorbed molecules at the interface. The molecule TDAE chemisorbed on gold is studied in paper V.
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Huijben, Mark. "Interface engineering for oxide electronics: tuning electronic properties by atomically controlled growth." Enschede : University of Twente [Host], 2006. http://doc.utwente.nl/55832.
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Unge, Mikael. "Molecular electronics : a theoretical study of electronic structure of bulk and interfaces /." Linköping : Univ, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-6938.
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Navaraj, William Ringal Taube. "Inorganic micro/nanostructures-based high-performance flexible electronics for electronic skin application." Thesis, University of Glasgow, 2019. http://theses.gla.ac.uk/40973/.
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Electronics in the future will be printed on diverse substrates, benefiting several emerging applications such as electronic skin (e-skin) for robotics/prosthetics, flexible displays, flexible/conformable biosensors, large area electronics, and implantable devices. For such applications, electronics based on inorganic micro/nanostructures (IMNSs) from high mobility materials such as single crystal silicon and compound semiconductors in the form of ultrathin chips, membranes, nanoribbons (NRs), nanowires (NWs) etc., offer promising high-performance solutions compared to conventional organic materials. This thesis presents an investigation of the various forms of IMNSs for high-performance electronics. Active components (from Silicon) and sensor components (from indium tin oxide (ITO), vanadium pentaoxide (V2O5), and zinc oxide (ZnO)) were realised based on the IMNS for application in artificial tactile skin for prosthetics/robotics. Inspired by human tactile sensing, a capacitive-piezoelectric tandem architecture was realised with indium tin oxide (ITO) on a flexible polymer sheet for achieving static (upto 0.25 kPa-1 sensitivity) and dynamic (2.28 kPa-1 sensitivity) tactile sensing. These passive tactile sensors were interfaced in extended gate mode with flexible high-performance metal oxide semiconductor field effect transistors (MOSFETs) fabricated through a scalable process. The developed process enabled wafer scale transfer of ultrathin chips (UTCs) of silicon with various devices (ultrathin chip resistive samples, metal oxide semiconductor (MOS) capacitors and n‐channel MOSFETs) on flexible substrates up to 4" diameter. The devices were capable of bending upto 1.437 mm radius of curvature and exhibited surface mobility above 330 cm2/V-s, on-to-off current ratios above 4.32 decades, and a subthreshold slope above 0.98 V/decade, under various bending conditions. While UTCs are useful for realizing high-density high-performance micro-electronics on small areas, high-performance electronics on large area flexible substrates along with low-cost fabrication techniques are also important for realizing e-skin. In this regard, two other IMNS forms are investigated in this thesis, namely, NWs and NRs. The controlled selective source/drain doping needed to obtain transistors from such structure remains a bottleneck during post transfer printing. An attractive solution to address this challenge based on junctionless FETs (JLFETs), is investigated in this thesis via technology computer-aided design (TCAD) simulation and practical fabrication. The TCAD optimization implies a current of 3.36 mA for a 15 μm channel length, 40 μm channel width with an on-to-off ratio of 4.02x 107. Similar to the NRs, NWs are also suitable for realizing high performance e-skin. NWs of various sizes, distribution and length have been fabricated using various nano-patterning methods followed by metal assisted chemical etching (MACE). Synthesis of Si NWs of diameter as low as 10 nm and of aspect ratio more than 200:1 was achieved. Apart from Si NWs, V2O5 and ZnO NWs were also explored for sensor applications. Two approaches were investigated for printing NWs on flexible substrates namely (i) contact printing and (ii) large-area dielectrophoresis (DEP) assisted transfer printing. Both approaches were used to realize electronic layers with high NW density. The former approach resulted in 7 NWs/μm for bottom-up ZnO and 3 NWs/μm for top-down Si NWs while the latter approach resulted in 7 NWs/μm with simultaneous assembly on 30x30 electrode patterns in a 3 cm x 3 cm area. The contact-printing system was used to fabricate ZnO and Si NW-based ultraviolet (UV) photodetectors (PDs) with a Wheatstone bridge (WB) configuration. The assembled V2O5 NWs were used to realize temperature sensors with sensitivity of 0.03% /K. The sensor arrays are suitable for tactile e-skin application. While the above focuses on realizing conventional sensing and addressing elements for e-skin, processing of a large amount of data from e-skin has remained a challenge, especially in the case of large area skin. A Neural NW Field Effect Transistors (υ-NWFETs) based hardware-implementable neural network (HNN) approach for tactile data processing in e-skin is presented in the final part of this thesis. The concept is evaluated by interfacing with a fabricated kirigami-inspired e-skin. Apart from e-skin for prosthetics and robotics, the presented research will also be useful for obtaining high performance flexible circuits needed in many futuristic flexible electronics applications such as smart surgical tools, biosensors, implantable electronics/electroceuticals and flexible mobile phones.
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Rajagopal, Subramanian. "Transition of low-volume complex electronic system industries to lead-free electronics." College Park, Md. : University of Maryland, 2003. http://hdl.handle.net/1903/116.
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Thesis (M.S.) -- University of Maryland, College Park, 2003Thesis research directed by: Dept. of Mechanical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Datar, Ashlesha. "The impact of changes in kindergarten entrance age policies on children's academic achievement and the child care needs of families." Santa Monica, Calif. : Rand, 2003. http://www.rand.org/publications/electronic/ed.html.
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Dogbe, John Kofi. "Comparing cluster and slab model geometries from density functional theory calculations of si(100)-2x1 surfaces using low-energy electron diffraction." abstract and full text PDF (free order & download UNR users only), 2007. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3258835.
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Bonifas, Andrew Paul. "Spectroscopy, Fabrication, and Electronic Characterization of Molecular Electronic Devices." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1305653420.
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Fard, Ali. "Analysis and Design of Low-Phase-Noise Integrated Voltage-Controlled Oscillators for Wide-Band RF Front-Ends." Doctoral thesis, Mälardalen University, Department of Computer Science and Electronics, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-88.
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The explosive development of wireless communication services creates a demand for more flexible and cost-effective communication systems that offer higher data rates. The obvious trend towards small-size and ultra low power systems, in combination with the ever increasing number of applications integrated in a single portable device, tightens the design constraints at hardware and software level. The integration of current mobile systems with the third generation systems exemplifies and emphasizes the need of monolithic multi-band transceivers. A long term goal is a software defined radio, where several communication standards and applications are embedded and reconfigured by software. This motivates the need for highly flexible and reconfigurable analog radio frequency (RF) circuits that can be fully integrated in standard low-cost complementary metal-oxide-semiconductor (CMOS) technologies.
In this thesis, the Voltage-Controlled Oscillator (VCO), one of the main challenging RF circuits within a transceiver, is investigated for today’s and future communication systems. The contributions from this work may be divided into two parts. The first part exploits the possibility and design related issues of wide-band reconfigurable integrated VCOs in CMOS technologies. Aspects such as frequency tuning, power dissipation and phase noise performance are studied and design oriented techniques for wide-band circuit solutions are proposed. For demonstration of these investigations several fully functional wide-band multi-GHz VCOs are implemented and characterized in a 0.18µm CMOS technology.
The second part of the thesis concerns theoretical analysis of phase noise in VCOs. Due to the complex process of conversion from component noise to phase noise, computer aided methods or advanced circuit simulators are usually used for evaluation and prediction of phase noise. As a consequence, the fundamental properties of different noise sources and their impact on phase noise in commonly adopted VCO topologies have so far not been completely described. This in turn makes the optimization process of integrated VCOs a very complex task. To aid the design and to provide a deeper understanding of the phase noise mechanism, a new approach based on a linear time-variant model is proposed in this work. The theory allows for derivation of analytic expressions for phase noise, thereby, providing excellent insight on how to minimize and optimize phase noise in oscillators as a function of circuit related parameters. Moreover, it enables a fair performance comparison of different oscillator topologies in order to ascertain which structure is most suitable depending on the application of interest. The proposed method is verified with very good agreement against both advanced circuit simulations and measurements in CMOS and bipolar technologies. As a final contribution, using the knowledge gained from the theoretical analysis, a fully integrated 0.35µm CMOS VCO with superior phase noise performance and power dissipation is demonstrated.
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Moore, Evan Guy. "A macrocyclic scaffold for electronic energy transfer and photoinduced electron transfer /." St. Lucia, Qld, 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe17983.pdf.
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Popescu, Radu‐Adrian. "Carborane derivatives with electron rich moieties. Synthesis, properties and electronic communication." Doctoral thesis, Universitat Autònoma de Barcelona, 2013. http://hdl.handle.net/10803/117472.
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El treball que es presenta en aquesta tesi és la continuació i ampliació de la feina feta en el nostre grup de recerca en els darrers anys sobre derivats de l’o-carborà que porten grups rics en electrons. L’objectiu global de la tesi és la síntesis i l’estudi teòric d’aquests derivats.
Gairebé tots els compostos sintetitzats en aquest treball s’han obtingut directament a partir de l’o-carborà. La funcionalització dels àtoms de carboni de l’o-carborà es fa en dos etapes. En un primer pas, s’afegeix un agent per arrancar el protons, com són els compostos organolitiats, les amides alcalines, els hidrurs alcalins; i tot seguit, s’afegeix un electròfil (diòxid de carboni, calcogen, halogen, halurs, epòxids, aldehids). Tot i que la substitució dels dos àtoms de carboni del clúster d’o-carborà S’obté pràcticament sempre, la monosubstitució no és gens trivial, perquè sempre ve acompanyada de la disubstitució. Per això, el primer objectiu d’aquest treball ha sigut l’estudi experimental i teòric de la influencia dels dissolvents eterats (Et2O, THF or DME) en la formació dels compostos organolitiats, utilitzant com a plataforma el 1,2-C2B10H12.
Tot i que les fosfines de l’o-carborà són uns dels derivats més estudiats, la investigació de les seves propietats electròniques no ho ha sigut tant. Les carboranilfosfines varen ésser sintetitzades per primer cop fa més de 50 anys, però cap estudi sistemàtic i exhaustiu sobre les reaccions d’oxidació s’havia fet fins ara. Per tant, un altre objectiu d’aquest treball ha sigut l’estudi de les reaccions d’oxidació de les carboranilfosfines amb peròxid d’hidrogen, sofre i seleni; i la seva avaluació com a lligands. Un cop sintetitzats aquests compostos, hem fet un estudi teòric que ha tingut els següents objectius: i) veure la influència dels grups fosfina i fosfina oxidada en els efects electrònics del clúster d’o-carborà; ii) veure els efectes electrònics en les closo-carboranilmonofosfines; iii) veure la labilitat del enllaç fòsfor-calcogen en els monocalcògens dels carboranilmono- i carboranildifosfines; iv) estudiar dels processos de oxidació i degradació; v) estudiar la comunicació intramolecular en les carboranildifosfines aniòniques oxidades.
Un altre grup ric en electrons és el grup formil (-CHO), que una vegada afegit a un clúster d’o-carborà, veure les seves propietats altament modificades. Tot i que el carboranilformaldehid es coneix des de fa temps, hi ha pocs estudis sobre la seva reactivitat. Per tant un altre objectiu d’aquest treball ha sigut l’estudi de la reactivitat d’aquest compost amb la finalitat d’obtenir nous derivats. Per això hem estudiat: i) l’addició nucleofílica al grup carbonílic del derivat litiat de l’o-carborà per obtenir derivats amb múltiples clústers d’o-carborà; ii) la substitució electrofílica dels substrats aromàtics emprant el carboranilformaldehid activat amb la finalitat d’obtenir derivats de l’o-carborà amb propietats luminescents; iii) les reaccions de Wittig i Horner-Wadaworth-Emmons emprant ja sigui el carboranilformaldehid ó els derivats de l’o-carborà amb grups fosfonat i sals de fosfoni.
Per l’últim hem estudiat la síntesis de nous derivats utilitzant com a plataforma la carboranilpiridina. Les reaccions estudiades han sigut: i) la metal·lació de la carboranilpiridina amb complexos de Pd(II), Ir(III), Rh(III) i Ru(II); ii) la síntesis de lligands híbrids carboranilpiridina-fosfina i les seves reaccions de complexació amb Pd(II) i Rh(I); iii) la síntesis de un derivat de la carboranilpiridina que inclou un grup borà; iv) la síntesis de un derivat cobaltabis(dicarballur)-dipiridina.The work presented in this manuscript is the continuation and extension of the work done in our group during the last years on the carborane derivatives with electron rich moieties. The main objective of this work is to synthesize and to study by computational means new derivatives of carborane with electron rich moieties. Almost all the compounds synthesized in this work are directly achieved from o-carborane. The direct modification of the C vertexes of the o-carborane is done in two steps. First a deprotonating agent as organolithium compounds, alkali-metal amides or alkali-metal hydrides is added, followed by the addition of a suitable electrophile (carbon dioxide, chalcogens, halogens, halides, epoxides, aldehydes). Although the substitution at the both carbon atoms is always achieved, the monosubstitution is not so trivial, being almost always accompanied by the disubstituted derivative. For that, the first specific objective of this work was to study both experimentally and by computational means the influence of ethereal solvents (Et2O, THF or DME) on the formation of organolithiated compounds, based on the 1,2-C2B10H12 platform. Though the o-carborane derivatives with phosphorus moieties were the most studied synthetically and some of their properties were exploited, still work has to be done to understand their electronic properties that may ultimate lead to a rationalized design of new derivatives. The carboranylphosphines are known for more than 50 years ago, but no systematic and comprehensive investigation on their oxidation reactions were found in the literature as well as investigations on the electronic properties of these phosphines. For that the second specific objective was the study of the oxidation of carboranylphsophines with hydrogen peroxide, sulphur and selenium and to examine their properties as ligands. Once the synthetic study on the carboranylphosphines and their oxides and chalcogenides was completed, we proceeded with the third specific objective that was the computational study of the carboranylphosphines and their oxides and chalcogenides. The computational study contains: i) the contribution of phosphine and oxidized phosphine moieties to the electronic effects on the o-carborane cluster; ii) electronic effects in closo-carboranylmonophosphines; iii) the lability of the phosphorus-chalcogen bonds in carboranylmono- and carboranyldiphsophine monochalcogenides; iv) the oxidation/degradation processes study; and v) intramolecular communication in oxidized anionic carboranyldiphosphines. Other moiety that is rich in electrons is the formyl group, that once attached to o-carborane cluster its properties are highly modified. Though the carboranylformadehyde is long known in the literature, studies on its reactivity are rare. For that, the fourth objective was to understand the reactivity carboranylformaldehyde as platform for new derivatives. For that we studied: i) the nucleophilic addition to the carbonyl group with lithated carborane in order to synthesize “confined space” multi-cage compounds; ii) the electrophilic substitution reactions of aromatic substrates with activated carboranylformaldehyde, in order to obtain derivatives with luminescent properties; and iii) the Wittig and Horner-Wadaworth-Emmons reaction using carboranylformaldehyde and carborane containing phosphonates and phosphonium salts. The fifth specific objective was the study of carboranylpyridine as platform for new derivatives, for which we studied: i) the metalation reaction of carboranylpyridine with Pd(II), Ir(III), Rh(III) and Ru(II); ii) synthesis of carboranylpyridine-phosphine hybrid ligands and complexation reactions of these ligands through Pd(II) and Rh(I) complexes; iii) synthesis of carboranylpyridine-borane derivative; and iv) synthesis of cobalta(bisdicarbollide)-pyridine derivative.
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Ji, Tao. "Inelastic electron tunneling spectroscopy in molecular electronic devices from first-principles." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=96883.
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In this thesis, we present the first-principle calculations of inelastic electron tunneling spectroscopy(IETS) in single molecular break junctions. In a two-probe electrode-molecule-electrode setup, density functional theory(DFT) is used for the construction of the Hamiltonian and the Keldysh non-equilibrium Green's function(NEGF) technique will be employed for determining the electron density in non-equilibrium system conditions. Total energy functional, atomic forces and Hessian matrix can be obtained in the DFT-NEGF formalism and self-consistent Born approximation(SCBA) is used to integrate the molecular vibrations (phonons) into the framework once the phonon spectra and eigenvectors are calculated from the dynamic matrix. Geometry optimization schemes will also be discussed as an indispensable part of the formalism as the equilibrium condition is crucial to correctly calculate the phonon properties of the system.To overcome the numerical difficulties, especially the large computational time demand of the electron-phonon coupling problem, we develop a numerical approximation for the electron self-energy due to phonons and the error is controlled within numerical precision. Besides, a direct IETS second order I-V derivative expression is derived to reduce the error of numerical differentiation under reasonable assumptions. These two approximations greatly reduce the computation requirement and make the calculation feasible within current numerical capability.As the application of the DFT-NEGF-SCBA formalism, we calculate the IETS of the gold-octanedithiol(ODT) molecular junction. The I-V curve, conductance and IETS from ab-inito calculations are compared directly to experiments. A microscopic understanding of the electron-phonon coupling mechanism in the molecular tunneling junctions is explained in this example. In addition, comparisons of the hydrogen-dissociative and hydrogen-non-dissociative ODT junctions as well as the different charge transfer behaviors are presented to show the effects of thiol formation in the ODT molecular junction.Dans cette thèse, nous présentons des calculs ab initio de la spectroscopie à effet tunnel par électron inélastique (IETS)appliqués à des jonctions moléculaires. Dans le cadre d'une configuration électrode-molécule-électrode,la théorie de la fonctionnelle de la densité (DFT) est utilisée pour construire l'hamiltonien et les fonctions de Green hors-équilibres(NEGF) sont employées pour déterminer la densité électroniquedans des conditions hors-équilibre. Le cadrede la DFT-NEGF nous permet de calculer des quantités telles que la fonctionnelle d'énergie totale,les forces atomiques ainsi que la matrice de Hessian. L'approximationauto-consistante de Born (SCBA) est employée afin d'intégrer les vibrations moléculaires (phonons) dans le formalisme DFT-NEGF,une fois que le spectre des phonons et les vecteurs propres ont été calculés à partir de la matrice dynamique. Des méthodes d'optimisations géométriques sont aussi discutées en tant que part indispensable du formalisme,étant donné que la condition d'équilibre mécanique est essentielle afin de calculer correctement les propriétés des phonons du système.Afin de surmonter les difficultés numériques, particulièrement concernant la grande demandecomputationnelle requise pour le calcul du couplage électron-phonon, nous développons une approximation numérique pour la self-énergie associée aux phonons. De plus, en employant quelques hypothèses raisonables, nous dérivons une expression pour l'IETS calculée à partir de laseconde dérivée de la courbe I-V dans le butde réduire l'erreur associée à la différentiation numérique. L'utilisation de ces deux approximations diminuent grandement les exigences computationnelles et rendent les calculs possibles avec les capacités numériques actuelles.Comme application du formalisme DFT-NEGF-SCBA, nous calculons l'IETS de la jonction moléculaire or-octanedithiol(ODT)-or. La courbe I-V, la conductance et l'IETS obtenues par calculs ab initio sontdirectement comparées aux données expérimentales. Une compréhension microscopique du couplage électron-phonon pour une jonction moléculaire à effet tunnel est élaborée dans cet exemple. De plus, des comparaisons entre les jonctions ODT à hydrogène dissociatif et à hydrogène non-dissociatif ainsi queles différents comportements de transfert de charges sont présentés afin de montrer les effets de la formation du thiol dans la jonction moléculaire ODT.