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Ion-sensing properties of 1D vanadium pentoxide nanostructures

Vieira, Nirton C. S.; Avansi, Waldir; Figueiredo, Alessandra; Ribeiro, Caue; Mastelaro, Valmor Roberto; Guimarães, Francisco Eduardo Gontijo
Fonte: SPRINGER; NEW YORK Publicador: SPRINGER; NEW YORK
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
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The application of one-dimensional (1D) V2O5 center dot nH(2)O nanostructures as pH sensing material was evaluated. 1D V2O5 center dot nH(2)O nanostructures were obtained by a hydrothermal method with systematic control of morphology forming different nanostructures: nanoribbons, nanowires and nanorods. Deposited onto Au-covered substrates, 1D V2O5 center dot nH(2)O nanostructures were employed as gate material in pH sensors based on separative extended gate FET as an alternative to provide FET isolation from the chemical environment. 1D V2O5 center dot nH(2)O nanostructures showed pH sensitivity around the expected theoretical value. Due to high pH sensing properties, flexibility and low cost, further applications of 1D V2O5 center dot nH(2)O nanostructures comprise enzyme FET-based biosensors using immobilized enzymes.; CAPES; CAPES; CNPq; CNPq; FAPESP; FAPESP

Ion-sensing properties of 1D vanadium pentoxide nanostructures

Vieira, Nirton C. S.; Avansi, Waldir; Figueiredo, Alessandra; Ribeiro, Caue; Mastelaro, Valmor R.; Guimares, Francisco E. G.
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica Formato: 5
ENG
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); The application of one-dimensional (1D) V2O5 center dot nH(2)O nanostructures as pH sensing material was evaluated. 1D V2O5 center dot nH(2)O nanostructures were obtained by a hydrothermal method with systematic control of morphology forming different nanostructures: nanoribbons, nanowires and nanorods. Deposited onto Au-covered substrates, 1D V2O5 center dot nH(2)O nanostructures were employed as gate material in pH sensors based on separative extended gate FET as an alternative to provide FET isolation from the chemical environment. 1D V2O5 center dot nH(2)O nanostructures showed pH sensitivity around the expected theoretical value. Due to high pH sensing properties, flexibility and low cost, further applications of 1D V2O5 center dot nH(2)O nanostructures comprise enzyme FET-based biosensors using immobilized enzymes.

Electrical properties of individual and small ensembles of InAs/InP nanostructures

Vicaro, K. O.; Gutiérrez, H. R.; Bortoleto, J. R R; Nieto, L.; Von Zuben, A. A G; Seabra, A. C.; Schulz, P. A.; Cotta, M. A.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Conferência ou Objeto de Conferência Formato: 1353-1358
ENG
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We investigate electrical properties of InAs/InP semiconductor nanostructures by conductive atomic force microscopy (C-AFM) and current measurements at low temperatures in processed devices. Different conductances and threshold voltages for current onset were observed for each type of nanostructure. In particular, the extremity of the wire could be compared to a dot with similar dimensions. The processed devices were used in order to access the in-plane conductance of an assembly of a reduced number of nanostructures. Here, fluctuations on I-V curves at low temperatures (<40 K) were observed. At these low temperatures and for a suitable range of applied voltages, random telegraph noise (RTN) in the current was observed for devices with dots. These fluctuations can be associated to electrons trapped in dots, as suggested by numerical simulations. A crossover from a semiconductor-like to a metallic transport behavior is also observed for similar parameters. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA.

Propriedades opticas e eletricas de nanoestruturas de Si; Optical and electrical properties of silicon nanostructures

Guilherme Osvaldo Dias
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 13/01/2009 PT
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Analisamos amostras de óxido de silício rico em silício (SRSO) obtidas por um sistema de deposição química de vapor com ressonância ciclotrônica de elétrons (ECR-CVD). Propriedades estruturais, de composição, ópticas e elétricas foram estudadas por transformada de Fourier de absorção no infravermelho (FTIR), microscopia eletrônica de transmissão (TEM), espectroscopia de retro-espalhamento Rutherford (RBS), fotoluminescência (PL), elipsometria e medidas de capacitância-tensão (C-V). Através do ajuste dos índices de refração em função do fluxo de O2 para uma longa faixa de razões de fluxo, pudemos notar que o sistema ECR-CVD permite obter filmes com alto controle desses índices de refração. Isto sugere indiretamente a possibilidade do controle das características ópticas e elétricas dos nossos filmes, pois essas características, assim como o índice de refração, são dependentes da concentração de silício nos filmes. Na região de concentração de interesse em nosso trabalho, a razão de concentração atômica O/Si obtida por RBS correlaciona-se linearmente com o índice de refração. As intensidades e posições dos picos de PL e as curvas de histereses observadas através de medidas C-V, após os tratamentos térmicos...

Projeto e construção de um reator para produção de nanoestruturas de carbono : síntese e caracterização de esferas de carbono produzidas a partir de resíduo da destilação molecular de petróleo; Design and construction of a reactor for carbon nanostructures production : synthesis and characterization of carbon spheres from petroleum molecular distillation residue

Carolina Macías Macías
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 06/10/2010 PT
Relevância na Pesquisa
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Após a descoberta dos nanotubos de Carbono, o estudo de novos materiais de Carbono surgiu como um fascinante assunto de pesquisa para a comunidade científica. As propriedades excepcionais destes materiais os fazem potenciais aditivos para lubrificantes, suportes para catalisadores, materiais para estocagem de energia, e materiais para dispositivos nanoeletrônicos. Técnicas de síntese muito versáteis como o método Laser-Forno e o método de Deposição Química de Vapor são usadas para produzir vários tipos de materiais de Carbono como nanotubos, esferas e fibras a partir de hidrocarbonetos líquidos e gasosos e de outras matérias-primas. Por outro lado, o processamento do petróleo gera resíduos que vêm sendo tratados por meio de processos inovadores como a Destilação Molecular visando à obtenção de produtos finais de alto valor agregado. Porém, esta técnica gera resíduos ainda mais pesados (ultrapesados) de petróleo de composição rica em hidrocarbonetos, resinas, asfaltenos, aromáticos e heteroátomos, característica que lhes confere potencial como precursores de estruturas carbonosas, mas paralelamente impõe desafios tecnológicos em função da sua complexidade. Neste contexto, o resíduo ultrapesado da destilação molecular aplicada ao resíduo de vácuo foi avaliado como matéria prima para a síntese de estruturas de carbono. Em razão disso...

Origem e estabilidade de nanoestruturas de InAs sobre ligas de InP e InGaAs; Origin and stability of InAs nanostructures on InP and InGaAs alloys

Luis Nieto Gonzalez
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 22/11/2007 PT
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Neste trabalho estudamos os mecanismos de crescimento durante a epitaxia por feixe químico de nanoestruturas III-V baseadas no sistema InAs/InP. Particularmente, foram estudados nanofios e ilhas de InAs sobre uma camada buffer InP(001) e nanofios de InAs sobre uma matriz de InGaAs/InP (com mesmo parâmetro de rede). Apresentaremos, nesta tese, as diferenças e similaridades destes sistemas quanto a condições de crescimento, distribuição de tamanho, forma e os efeitos de volume da camada de InGaAs sobre as nanoestruturas de InAs quando comparadas ao sistema InAs/InP. Nossa escolha do InGaAs/InP como camada buffer para a nucleação dos fios de InAs, foi feita porque facilitaria a utilização deste sistema em diversas aplicações, proporcionando maior flexibilidade no desenho dos dispositivos. Por outro lado, este material abre a possibilidade de controlar as características das nanoestruturas através das propriedades de bulk e superficiais da liga ternária InGaAs. Além disso, ligas ternárias podem exibir efeitos de volume que afetam suas propriedades superficiais. Estes fenômenos podem afetar a nucleação dos fios quânticos e por isso foram objeto de nosso estudo. Para isso utilizamos e correlacionamos medidas in situ de difração de elétrons de alta energia (RHEED)...

Design of nanostructures, obtained from assembling of α-lactalbumin and lysozyme upon heat treatment and selective environmental conditions

Monteiro, Adenilson A.; Monteiro, Márcia R.; Ramos, Óscar L.; Pereira, Ricardo; Diniz, Renata; Costa, Angélica R.; Malcata, F. X.; Teixeira, J. A.; Teixeira, Álvaro V.; Oliveira, Eduardo B.; Vicente, A. A.; Coimbra, Jane Sélia dos Reis
Fonte: Universidade do Minho. Departamento de Engenharia Biológica Publicador: Universidade do Minho. Departamento de Engenharia Biológica
Tipo: Conferência ou Objeto de Conferência
Publicado em 15/10/2014 ENG
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Protein assembly into supramolecular structures (e.g. aggregates, fibrils and nanotubes) is a widespread phenomenon in biological sciences. Nowadays, it is well documented that the amphiphilic properties of proteins is a driving force to their self-assembling into innovative micro- and nanostructures of high interest in the food and pharmaceutical fields. Formation of such structures is strongly dependent on physicochemical conditions and protein conformation. In this study, bio-based nanostructures were produced from assembly of hen egg white lysozyme (Lys) and bovine α-lactalbumin (α-La) – i.e. two homologous globular proteins with opposite charge), under various processing conditions: heating treatment (55 °C and 75 °C), holding time (25 and 35 min) and pH (3 and 11). The nano-scale structures prepared by solubilization of 2 mg mL-1 of Lys and α-La powders in water, at a molar ratio of 1:0.54, were characterized via dynamic light scattering (in terms of particle size, polydispersity and zeta potential), and further analyzed by transmission electron microscopy (TEM). Smaller sized particles (75 nm) and low podydispersity values (0.24) were produced at pH 11 after heating at 75 °C for 25 min, whereas at pH 3 (and similar conditions) the average mean particle size was ca. 402 nm with polydispersity of 0.45. The nanostructure stability was also assessed; higher stability was obtained at pH 11 than 3...

Modulation of the catalytic activity of porphyrins by lipid-and surfactant-containing nanostructures

Nantes,Iseli L; Durán,Nelson; Pinto,Sandra M. S; Silva,Fabiana B. da; Souza,Juliana S. de; Isoda,Noemia; Luz,Roberto A. S; Oliveira,Tiara G. de; Fernandes,Vinícius G
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2011 EN
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The structural factors modulating porphyrin activity encompass pyrrole and equatorial ligands, as well as the central metal and the number and structure of their axial ligands. Of equal importance is the microenvironment provided by apoproteins, solvents and membranes. Porphyrins are often used to construct supramolecular structures with different applications. The modulation of activity of the porphyrins has been frequently achieved by mimicking nature, i.e., by the provision of different microenvironments for these molecules. The association of porphyrins to surfactant- and lipid-containing nanostructures has changed the activity of these compounds to mimic different enzymes such as SOD, cytochrome P450, peroxidases and others. In determined conditions, the reactive forms of the porphyrins are high-valence states of oxo-metal-πcations and oxo-metal produced by the reaction with peroxides and peracids. The modulation of porphyrin activity by surfactant- and lipid-containing nanostructures has also been achieved for hemeproteins, as the lipid nanostructures affect the conformation of proteins.

Enhanced Zinc Oxide and Graphene Nanostructures for Electronics and Sensing Applications

Verma, Ved P
Fonte: FIU Digital Commons Publicador: FIU Digital Commons
Tipo: Artigo de Revista Científica Formato: application/pdf
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Zinc oxide and graphene nanostructures are important technological materials because of their unique properties and potential applications in future generation of electronic and sensing devices. This dissertation investigates a brief account of the strategies to grow zinc oxide nanostructures (thin film and nanowire) and graphene, and their applications as enhanced field effect transistors, chemical sensors and transparent flexible electrodes. Nanostructured zinc oxide (ZnO) and low-gallium doped zinc oxide (GZO) thin films were synthesized by a magnetron sputtering process. Zinc oxide nanowires (ZNWs) were grown by a chemical vapor deposition method. Field effect transistors (FETs) of ZnO and GZO thin films and ZNWs were fabricated by standard photo and electron beam lithography processes. Electrical characteristics of these devices were investigated by nondestructive surface cleaning, ultraviolet irradiation treatment at high temperature and under vacuum. GZO thin film transistors showed a mobility of ~5.7 cm 2/ V•s at low operation voltage of <5 V and a low turn-on voltage of>~0.5 V with a sub threshold swing of ~85 mV/decade. Bottom gated FET fabricated from ZNWs exhibit a very high on-to-off ratio (~10 6) and mobility (∼28 cm 2 /V•s). A bottom gated FET showed large hysteresis of ~5.0 to 8.0 V which was significantly reduced to ~1.0 V by the surface treatment process. The results demonstrate charge transport in ZnO nanostructures strongly depends on its surface environmental conditions and can be explained by formation of depletion layer at the surface by various surface states. A nitric oxide (NO) gas sensor using single ZNW...

Ellipsoidal hollow nanostructures assembled from anatase TiO₂ nanosheets as a magnetically separable photocatalyst; Ellipsoidal hollow nanostructures assembled from anatase TiO(2) nanosheets as a magnetically separable photocatalyst

Chen, J.; Chen, C.; Liu, J.; Xu, R.; Qiao, S.; Lou, X.
Fonte: Royal Soc Chemistry Publicador: Royal Soc Chemistry
Tipo: Artigo de Revista Científica
Publicado em //2011 EN
Relevância na Pesquisa
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A simple approach was proposed to synthesize three types of ellipsoidal hollow nanostructures whose shells are assembled from anatase TiO₂ nanosheets (NSs) with exposed (001) facets. Among them, ellipsoid Fe₃O₄@TiO₂-NS nanorattles can be readily generated as a magnetically separable photocatalyst with enhanced activity through in situ reduction of the α-Fe₂O₃ core.; Jun Song Chen, Chunping Chen, Jian Liu, Rong Xu, Shi Zhang Qiao and Xiong Wen Lou

Coarse-grained simulations of the solution-phase self-assembly of poly(3-hexylthiophene) nanostructures

Schwarz, K.; Kee, T.; Huang, D.
Fonte: Royal Society of Chemistry Publicador: Royal Society of Chemistry
Tipo: Artigo de Revista Científica
Publicado em //2013 EN
Relevância na Pesquisa
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Under certain conditions the conjugated polymer poly(3-hexylthiophene) (P3HT) self-assembles into high-aspect-ratio nanostructures (known as nanofibres, nanowires, or nanoribbons) when cooled below its solubility limit in a marginal solvent such as anisole. Such nanostructures are potentially beneficial for organic photovoltaic device performance. In this work, Langevin dynamics simulations of a coarse-grained model of P3HT in implicit anisole solvent are used to study the self-assembly of P3HT nanostructures for polymer chain lengths and concentrations used experimentally to prepare P3HT nanofibres. The coarse-grained model is parametrised to match the local structure and dynamics of an atomistic model with explicit solvent. Nanofibres are also prepared experimentally and characterised by atomic force microscopy and UV-vis spectroscopy. The simulations match the experimental phase behaviour of P3HT in anisole, showing aggregation of P3HT at 293 and 308 K but not at 323 or 353 K. Single-chain simulations at 293 K reveal two distinct nano-scale aggregate morphologies: hairpins and helices. Hairpin aggregates, which are the precursors of nanofibres, are slightly favoured energetically at 293 K for nuclei of the critical size of ≈80 monomers for aggregation. Consequently...

Determination of join regions between carbon nanostructures using variational calculus

Baowan, D.; Cox, B.; Hill, J.
Fonte: Australian Mathematical Society Publicador: Australian Mathematical Society
Tipo: Artigo de Revista Científica
Publicado em //2013 EN
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We review the work of the present authors to employ variational calculus to formulate continuous models for the connections between various carbon nanostructures. In formulating such a variational principle, there is some evidence that carbon nanotubes deform as in perfect elasticity, and rather like the elastica, and therefore we seek to minimize the elastic energy. The calculus of variations is utilized to minimize the curvature subject to a length constraint, to obtain an Euler–Lagrange equation, which determines the connection between two carbon nanostructures. Moreover, a numerical solution is proposed to determine the geometric parameters for the connected structures. Throughout this review, we assume that the defects on the nanostructures are axially symmetric and that the into-the-plane curvature is small in comparison to that in the two-dimensional plane, so that the problems can be considered in the two-dimensional plane. Since the curvature can be both positive and negative, depending on the gap between the two nanostructures, two distinct cases are examined, which are subsequently shown to smoothly connect to each other.; D. Baowan, B. J. Cox And J. M. Hill

Modelling interaction of DNA with carbon nanostructures.

Alshehri, Mansoor Hassan S.
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2014
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This thesis focuses on the development of mathematical models for the interaction between deoxyribonucleic acid molecules (DNA) and certain carbon nanostructures. We model such atomic interactions by adopting the 6-12 Lennard-Jones potential and the continuum approach. The latter assumes that a discrete atomic structure can be replaced with an average constant atomic surface density of atoms that is assumed to be smeared over each molecule, in our case a DNA molecule and a carbon nanostructure. First, we develop a mathematical model for the interaction between a deoxyribonucleic acid molecule and a carbon nanotube, and we examine the storage of DNA molecules in carbon nanotubes. Following earlier authors, the carbon nanotube is modelled as a right circular cylinder, while the helical structure of the DNA molecule is modelled as a continuously twisted ribbon. We next determine the binding energies between DNA molecules interacting with a graphene sheet, and finally, we determine the binding energies of a C₆₀ fullerene interacting with a DNA molecule. Experiments in nanotechnology are often expensive and time consuming, and mathematical models and numerical simulations are necessary to complement the efforts of experimentalists and to confirm observed experimental outcomes. Despite recent improvements in the rapidity of numerical simulations...

Complex Plasmonic Nanostructures: Symmetry Breaking and Coupled Systems

Lassiter, J. Britt
Fonte: Universidade Rice Publicador: Universidade Rice
ENG
Relevância na Pesquisa
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Metallic nanostructures support resonant oscillations of their conduction band electrons called localized surface plasmon resonances. Plasmons couple efficiently to light and have enabled a new class of technology for the manipulation of light at the nanoscale. Nanostructures that support plasmon resonances have the potential for a wide range of applications such as enhanced optical spectroscopy techniques for chemical- and bio-sensing, cancer diagnosis and therapy, metamaterials, and energy harvesting. As the field of plasmonics has progressed, these applications have become more sophisticated, requiring increasingly complex nanostructures. For example, coupled nanostructures of two or more nanoparticles are used extensively in plasmon-enhanced spectroscopy techniques because they exhibit extremely large optical field enhancements. Asymmetric nanostructures, such as nanocups (metallic semishells), have been shown to support magnetic modes that could be used in metamaterials applications. This class of complex plasmonic nanostructures holds great potential for both the observation of new physical phenomena and practical applications. This thesis will focus on the fabrication and characterization of several examples of these complex nanostructures using darkfield spectroscopy. The plasmon modes of a dimer consisting of two nanoshells are investigated in both the separated and conductively overlapping regimes and are interpreted using the plasmon hybridization model. Next...

Out-of-plane exchange bias in [Pt/Co]–IrMn bilayers sputtered on prepatterned nanostructures

Bollero, A.; Baltz, V.; Rodmacq, B.; Dieny, B.; Landis, S.; Sort Viñas, Jordi
Fonte: Universidade Autônoma de Barcelona Publicador: Universidade Autônoma de Barcelona
Tipo: Artigo de Revista Científica Formato: application/pdf
Publicado em //2006 ENG
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This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.; Exchange bias effects along the out-of-plane direction have been investigated in arrays of 100nmnanostructures prepared on top of prepatterned substrates, consisting of a ferromagnetic [Pt/Co] multilayer with out-of-plane anisotropy exchange coupled to an antiferromagnetic IrMn layer. A significant loop shift is observed in these nanostructures (dots and trenches). The relative evolutions of the bias fields with the IrMn thickness in the nanostructures and in the continuous film are ascribed to both the effects of the IrMn domain size and thermal activation. Lower coordinated spins in the trenches and at the dot edges are assumed to play a key role on the bias properties. A reduction of the blocking temperature is observed for both the dots and the trenches with respect to the continuous film.

Perpendicular exchange bias in antiferromagnetic-ferromagnetic nanostructures

Sort Viñas, Jordi; Dieny, B.; Fraune, M.; Koenig, C.; Lunnebach, F.; Beschoten, B.; Guntherodt, G.
Fonte: Universidade Autônoma de Barcelona Publicador: Universidade Autônoma de Barcelona
Tipo: Artigo de Revista Científica Formato: application/pdf
Publicado em //2004 ENG
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This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.; Exchange bias effects have been induced along the perpendicular-to-film direction in nanostructures prepared by electron beamlithography, consisting of a ferromagnetic [Pt/Co] multilayer exchange coupled to an antiferromagnet (FeMn). As a general trend, the exchange bias field and the blocking temperature decrease, whereas the coercivity increases, as the size of the nanostructures is reduced.

Plasmonic nanoengineering in hollow metal nanostructures: an electron energy-loss spectroscopy study

Genç, Aziz; Granados i García, Xavier
Fonte: [Barcelona] : Universitat Autònoma de Barcelona, Publicador: [Barcelona] : Universitat Autònoma de Barcelona,
Tipo: Tesis i dissertacions electròniques; info:eu-repo/semantics/doctoralThesis; info:eu-repo/semantics/publishedVersion
Publicado em //2015 ENG
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Resumen en Español Las nanoestructuras metálicas están siendo objeto de gran atención dada su capacidad para generar resonancias plasmónicas, que son oscilaciones colectivas de electrones alojados en la banda de conducción en un metal excitado por efecto de un campo electromagnético. El creciente interés entorno a las nanoestructuras metálicas como fuentes de plasmones, ha resultado en el desarrollo de un nuevo campo, la plasmónica, definida como la ciencia y tecnología de la generación, control y manipulación de las excitaciones resultantes de las interaciones de la luz con la materia. Las nanoestructuras plasmónicas encuentran aplicaciones en diversos campos que cubren biología, física, química, ingeniería y medicina. Por ejemplo, son ampliamente usados en sensores, espectroscopía Raman aumentada por la superficie (SERS), celdas solares potenciadas con plasmones, fotodetectores, sistemas de transporte de medicamentos en el cuerpo y terapia de cáncer, así como nanoláseres, capas de invisibilidad y computación cuántica. Es bien sabido que las propiedades plasmónicas de las nanoestructuras metálicas se ven muy afectadas por diferentes parámetros, como el tamaño, la forma, la composición y las condiciones ambientales. Por tanto...

The Thermo-Mechanical Dynamics of DNA Self-Assembled Nanostructures

Mao, Vincent Chi Ann
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Dissertação Formato: 7504848 bytes; application/pdf
Publicado em //2010 EN_US
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The manufacturing of molecular-scale computing systems requires a scalable, reliable, and economic approach to create highly interconnected, dense arrays of devices. As a candidate substrate for nanoscale logic circuits, DNA self-assembled nanostructures have the potential to fulfill these requirements. However, a number of open challenges remain, including the scalability of DNA self-assembly, long-range signal propagation, and precise patterning of functionalized components. These challenges motivate the development of theory and experimental techniques to illuminate the connections among the physical, optical, and thermodynamic properties of DNA self-assembled nanostructures.

In this thesis, three tools are developed, validated, and applied to study the thermo-mechanical properties of DNA nanostructures: 1) a method to quantitatively measure the quality of DNA grid self-assembly, 2) a spectrofluorometer capable of capturing fluorescence and absorbance data under simultaneous multi-wavelength excitation, and 3) a Monte Carlo simulator that models the ensemble response of DNA nanostructures as simple harmonic oscillators.

The broad contributions of this dissertation are as follows: 1) insight into the thermo-mechanical properties of DNA grid nanostructures...

New advances in magnetic nanostructures

Morán-López,J.L
Fonte: Sociedad Mexicana de Física Publicador: Sociedad Mexicana de Física
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2007 EN
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Some of the new developments on magnetic nanostructures are reviewed. The advances on the synthesis, characterization, and understanding of magnetic nanoclusters, magnetic nanowires and single molecule magnets are discussed. Particular emphasis is made on the magnetic properties of: a) magnetic iron nanowires encapsulated in carbon nanotubes, and b) manganese nanostructures which show a very rich and complex behavior. Both systems are good candidates for technological applications.

Microwave plasma-enhanced chemical vapour deposition growth of carbon nanostructures

Singh,Shivan R.; Leigh Jarvis,A.L.
Fonte: South African Journal of Science Publicador: South African Journal of Science
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2010 EN
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The effect of various input parameters on the production of carbon nanostructures using a simple microwave plasma-enhanced chemical vapour deposition technique has been investigated. The technique utilises a conventional microwave oven as the microwave energy source. The developed apparatus is inexpensive and easy to install and is suitable for use as a carbon nanostructure source for potential laboratory-based research of the bulk properties of carbon nanostructures. A result of this investigation is the reproducibility of specific nanostructures with the variation of input parameters, such as carbon-containing precursor and support gas flow rate. It was shown that the yield and quality of the carbon products is directly controlled by input parameters. Transmission electron microscopy and scanning electron microscopy were used to analyse the carbon products; these were found to be amorphous, nanotubes and onion-like nanostructures.