Página 1 dos resultados de 1573 itens digitais encontrados em 0.028 segundos

Sensores químicos com transdução microeletrônica e ótica utilizando polianilina nanoestruturada; Chemical sensors with optical and microelectronic transduction using nanostructured polyaniline

Mello, Hugo José Nogueira Pedroza Dias
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 20/10/2014 Português
Relevância na Pesquisa
46.07%
A área de sensores é uma das mais importantes do mundo tecnológico e científico moderno. O monitoramento contínuo de processos através de variáveis de diversas naturezas está presente em áreas como indústria, agricultura, biologia, meio ambiente, e centros de pesquisa. Os sensores químicos de pH fazem parte deste conjunto por analisar um dos parâmetros mais importantes em muitas áreas. Neste trabalho, o uso de filmes finos de polianilina (PANI) eletrodepositada em sensores de pH foi estudado. Duas configurações do sensor EGFET (Extended Gate Field-Effect Transistor) foram estudadas: o sensor Single-EGFET (S-EGFET) e o sensor Instrumental Amplifier-EGFET (IA-EGFET). Os filmes foram analisados nos dois sistemas e a sensibilidade e linearidade de cada sensor, comparada. Valores iniciais de sensibilidade no sensor IA-EGFET foram reduzidas devido a protonação interna do polímero quando medidos no sensor S-EGFET. Observamos uma relação entre quantidade de material polimérico depositado e o grau de alteração dos parâmetros. Os filmes de PANI foram estudados em sensores IA-EGFET como passo inicial para aplica-los em sensores diferencias, Diferencial-IA-EGFET (D-IA-EGFET). Desenvolveu-se o sensor diferencial por esse apresentar a vantagem de ser insensível a ruído (temperatura...

Contribuição das configurações de sistemas de acionamento e de seus componentes naturais no controle de interferências eletromagnéticas.; Contribution of drive systems configurations and their natural components in the control of electromagnetic interferences.

Winnischofer, Godofredo
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 06/06/2014 Português
Relevância na Pesquisa
36.07%
Nos últimos 20 anos, o inversor de frequência PWM passou a ser largamente utilizado. Dentre as razões principais de sua ampla difusão, cita-se a introdução do IGBT que, devido à sua capacidade de comutação rápida, possibilitou a redução de perdas, tamanho e custo dos conversores, ao mesmo tempo em que permitiu o uso do motor de indução em aplicações que demandam alto desempenho dinâmico. Porém, esta mesma característica que trouxe tais benefícios, contribuiu para acentuar os efeitos relacionados a fenômenos eletromagnéticos, devido à rápida transição que produz sinais em alta frequência, responsáveis por tornar os sistemas de acionamentos potenciais fontes de interferência eletromagnética. Os principais fenômenos desta natureza são a tensão de onda refletida, associada a ruídos de modo diferencial, e a corrente de modo comum. De maneira geral, a corrente de modo comum tem maior potencial de contribuição para a emissão radiada que a de modo diferencial e, em sistemas de acionamento, constitui a principal fonte de interferência eletromagnética. Esta não é resultado apenas da rápida comutação dos IGBTs, mas, também, da configuração do sistema, que propicia o surgimento das tensões de modo comum. Este trabalho visa estudar alternativas que minimizem...

Design of self-checking fully differential circuits and boards

Lubaszewski, Marcelo Soares; Mir, Salvador; Kolarik, Vladimir; Nielsen, Christian; Courtois, Bernard
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Artigo de Revista Científica Formato: application/pdf
Português
Relevância na Pesquisa
35.8%
A design methodology for on-line testing analog linear fully differential (FD) circuits is presented in this work. The test strategy is based on concurrently monitoring via an analog checker the common mode (CM) at the inputs of all amplifiers. The totally self-checking (TSC) goal is achieved for linear FD implementations provided that the checker CM threshold is small enough with respect to the specified margins of erroneous behavior in the circuit outputs. The design methodology is illustrated for a switched-capacitor biquadratic filter and the self-checking properties evaluated for a hard/soft-fault model. A large checker threshold of 100 mV of CM is chosen since the filter implementation does not minimize nonidealities (e.g., amplifier offsets or clock feedthrough) which result in significant CM components. The circuit outputs are accepted to deviate within a 10% band. With the implemented checker, the TSC goal is not achieved for some faults in narrow regions of the frequency band. For the worst case, a hard fault which results in a 31% deviation is undetected in only a narrow band of approximately 310 Hz. The circuit can be made TSC with a checker threshold of 40 mV and an accepted output deviation of 15%. This is, however, more demanding on the checker (which currently takes less than 3% of the total area and about 7.6% of the total power) and requires an improved filter implementation to reduce CM components. Our solution consists of relaxing a bit the TSC property of the functional block and applying a periodical off-line test to make the checker strongly code disjoint (SCD). This is easy to implement since an off-line test is also required for the checker. The checker outputs a double-rail error indication which ensures compatibility with digital checkers and makes the design of self-checking mixed signal circuits straightforward. The circuit-level mixed-signal approach is extended to the board level by means of the IEEE Std. 1149.1 digital test bus.

A simplified method for determining the high frequency induction motor equivalent electrical circuit parameters to be used in EMI effect

Riehl, Rudolf Ribeiro; Ruppert Filho, Ernesto
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Conferência ou Objeto de Conferência Formato: 1244-1248
Português
Relevância na Pesquisa
46.04%
The aim of this paper is to present a simple method for determining the high frequency parameters of a three-phase induction motor to be used in studies involving variable speed drives with PWM three-phase inverters, in which it is necessary to check the effects caused to the motor by the electromagnetic interference, (EMI) in the differential mode, as well as in the common mode. The motor parameters determination is generally performed in adequate laboratories using accurate instruments, such as very expensive RLC bridges. The method proposed here consists in the identification of the motor equivalent electrical circuit parameters in rated frequency and in high frequency through characteristic tests in the laboratory, together with the use of characteristic equations and curves, shown in the references to be mentioned for determining the motor high frequency parasite capacitances and also through system simulations using dedicated software, like Pspice, determining the characteristic waveforms involved in the differential and common mode phenomena, comparing and validating the procedure through published papers [01].

Microwave interferometric technique for characterizing few mode fibers

Wang, Lixian; Jin, Cang; Messaddeq, Younes; Larochelle, Sophie
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 1695-1698
Português
Relevância na Pesquisa
35.87%
We propose and experimentally demonstrate a simple and accurate technique for measuring differential mode group delay (DMGD) in few mode fibers (FMF). A frequency-swept microwave signal is modulated on a filtered optical incoherent source. The microwave signals carried on different fiber modes experience different time delays and interfere with each other in the photodetector. Optical interference between propagating fiber modes is avoided by the use of an incoherent optical source. A mathematical model is established to analyze the interference pattern and extract the DMGD values. A 456-m two-mode fiber and a 981-m FMF, which supports four LP modes, are measured. The measurement covers the whole C-band and the results coincide well with those obtained by the time-of-flight method and the numerical simulations. A precision of ±0.002 ps/m is achieved.

Functional properties and differential mode of regulation of the nitrate transporter from a plant symbiotic ascomycete

Montanini, Barbara; Viscomi, Arturo R.; Bolchi, Angelo; Martin, Yusé; Siverio, José M.; Balestrini, Raffaella; Bonfante, Paola; Ottonello, Simone
Fonte: Portland Press Ltd. Publicador: Portland Press Ltd.
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
35.83%
Nitrogen assimilation by plant symbiotic fungi plays a central role in the mutualistic interaction established by these organisms, as well as in nitrogen flux in a variety of soils. In the present study, we report on the functional properties, structural organization and distinctive mode of regulation of TbNrt2 (Tuber borchii NRT2 family transporter), the nitrate transporter of the mycorrhizal ascomycete T. borchii. As revealed by experiments conducted in a nitrate-uptake-defective mutant of the yeast Hansenula polymorpha, TbNrt2 is a high-affinity transporter (Km=4.7 μM nitrate) that is bispecific for nitrate and nitrite. It is expressed in free-living mycelia and in mycorrhizae, where it preferentially accumulates in the plasma membrane of root-contacting hyphae. The TbNrt2 mRNA, which is transcribed from a single-copy gene clustered with the nitrate reductase gene in the T. borchii genome, was specifically up-regulated following transfer of mycelia to nitrate- (or nitrite)-containing medium. However, at variance with the strict nitrate-dependent induction commonly observed in other organisms, TbNrt2 was also up-regulated (at both the mRNA and the protein level) following transfer to a nitrogen-free medium. This unusual mode of regulation differs from that of the adjacent nitrate reductase gene...

Global gene expression and Ingenuity biological functions analysis on PCB 153 and 138 induced human PBMC in vitro reveals differential mode(s) of action in developing toxicities

Ghosh, Somiranjan; Zang, Shizhu; Mitra, Partha S.; Ghimbovschi, Svetlana; Hoffman, Eric P.; Dutta, Sisir K.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
35.83%
Several reports have indicated that low level of polychlorinated biphenyl (PCB) exposure can adversely affect a multitude of physiological disorders and diseases in in vitro, in vivo, and as reported in epidemiological studies. This investigation is focused on the possible contribution of two most prevalent PCB congeners in vitro in developing toxicities. We used PCB 138 and 153 at the human equivalence level as model agents to test their specificity. We chose a global approach using oligonucleotide microarray technology to investigate modulated gene expression for biological effects, upon exposure of PCBs, followed by Ingenuity Pathway Analysis (IPA), to understand the underlying consequence in developing disease and disorders. We performed in vitro studies with human peripheral blood mononuclear cells (PBMC), where PBMC cells were exposed to respective PCBs for 48 hrs. Overall, our observation on gene expression indicated that PCB produces a unique signature affecting different pathways, specific for each congener. While analyzing these data through IPA, the prominent and interesting disease and disorders were Neurological disease, Cancer, Cardiovascular disease, respiratory disease, as well as endocrine system disorders Genetic disorders...

Common-Mode Differential-Mode (CMDM) Method for Double-Nuclear MR Signal Excitation and Reception at Ultrahigh Fields

Pang, Yong; Zhang, Xiaoliang; Xie, Zhentian; Wang, Chunsheng; Vigneron, Daniel. B.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
46.09%
Double-tuned radio-frequency (RF) coils for heteronuclear mangentic resonance (MR) require sufficient electromagnetic isolation between the two resonators operating at two Larmor frequencies and independent tuning in order to attain highly efficient signal acquisition at each frequency. In this work, a novel method for double-tuned coil design at 7T based on the concept of common-mode differential-mode (CMDM) was developed and tested. Common mode (CM) and differential mode (DM) currents exist within two coupled parallel transmission lines, e.g., microstrip lines, yielding two different current distributions. The electromagnetic (EM) fields of the CM and DM are orthogonal to each other, and thus, the two modes are intrinsically EM decoupled. The modes can be tuned independently to desired frequencies, thus satisfying the requirement of dual-frequency MR applications. To demonstrate the feasibility and efficiency of the proposed CMDM technique, CMDM surface coils and volume coils using microstrip transmission line for 1H and 13C MRI/MRSI were designed, constructed, and tested at 7T. Bench test results showed that the isolations between the two frequency channels of the CMDM surface coil and volume coil were better than −30 and −25 dB...

Planar Quadrature RF Transceiver Design Using Common-Mode Differential-Mode (CMDM) Transmission Line Method for 7T MR Imaging

Li, Ye; Yu, Baiying; Pang, Yong; Vigneron, Daniel B.; Zhang, Xiaoliang
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 12/11/2013 Português
Relevância na Pesquisa
46.1%
The use of quadrature RF magnetic fields has been demonstrated to be an efficient method to reduce transmit power and to increase the signal-to-noise (SNR) in magnetic resonance (MR) imaging. The goal of this project was to develop a new method using the common-mode and differential-mode (CMDM) technique for compact, planar, distributed-element quadrature transmit/receive resonators for MR signal excitation and detection and to investigate its performance for MR imaging, particularly, at ultrahigh magnetic fields. A prototype resonator based on CMDM method implemented by using microstrip transmission line was designed and fabricated for 7T imaging. Both the common mode (CM) and the differential mode (DM) of the resonator were tuned and matched at 298MHz independently. Numerical electromagnetic simulation was performed to verify the orthogonal B1 field direction of the two modes of the CMDM resonator. Both workbench tests and MR imaging experiments were carried out to evaluate the performance. The intrinsic decoupling between the two modes of the CMDM resonator was demonstrated by the bench test, showing a better than -36 dB transmission coefficient between the two modes at resonance frequency. The MR images acquired by using each mode and the images combined in quadrature showed that the CM and DM of the proposed resonator provided similar B1 coverage and achieved SNR improvement in the entire region of interest. The simulation and experimental results demonstrate that the proposed CMDM method with distributed-element transmission line technique is a feasible and efficient technique for planar quadrature RF coil design at ultrahigh fields...

Parallel imaging performance investigation of an 8-channel common-mode differential-mode (CMDM) planar array for 7T MRI

Hu, Xiaoqing; Chen, Xiao; Liu, Xin; Zheng, Hairong; Li, Ye; Zhang, Xiaoliang
Fonte: AME Publishing Company Publicador: AME Publishing Company
Tipo: Artigo de Revista Científica
Publicado em /02/2014 Português
Relevância na Pesquisa
45.98%
An 8-channel planar phased array was proposed based on the common-mode differential-mode (CMDM) structure for ultrahigh field MRI. The parallel imaging performance of the 8-channel CMDM planar array was numerically investigated based on electromagnetic simulations and Cartesian sensitivity encoding (SENSE) reconstruction. The signal-to-noise ratio (SNR) of multichannel images combined using root-sum-of-squares (rSoS) and covariance weighted root-sum-of-squares (Cov-rSoS) at various reduction factors were compared between 8-channel CMDM array and 4-channel CM and DM array. The results of the study indicated the 8-channel CMDM array excelled the 4-channel CM and DM in SNR. The g-factor maps and artifact power were calculated to evaluate parallel imaging performance of the proposed 8-channel CMDM array. The artifact power of 8-channel CMDM array was reduced dramatically compared with the 4-channel CM and DM arrays demonstrating the parallel imaging feasibility of the CMDM array.

Analysis of discrepancies between measured and predicted conducted emissions in switched-mode power supplies

Kyriazis, Gregory Amaral
Fonte: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia Publicador: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia
Tipo: Trabalho apresentado em evento / Paper
Português
Relevância na Pesquisa
35.87%
3 p. : il.; An equivalent disturbance generator model that considers the snubber circuit is applied to predict the emission of a flyback-type switched-mode power supply. Common and differential mode voltages are calculated using a SPICE simulator. The conducted emission and its common mode component are measured to validate the prediction model.

Analysis of discrepancies between measured and predicted conducted emissions in switched-mode power supplies

Kyriazis, Gregory Amaral
Fonte: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia Publicador: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
35.87%
3 p.: il.; An equivalent disturbance generator model that considers the snubber circuit is applied to predict the emission of a flyback-type switched-mode power supply. Common and differential mode voltages are calculated using a SPICE simulator. The conducted emission and its common mode component are measured to validate the prediction model

S-shaped complementary split ring resonators and their application to compact differential bandpass filters with common-mode suppression

Karami Horestani, A.; Duran-Sindreu, M.; Naqui, J.; Fumeaux, C.; Martin, F.
Fonte: IEEE Publicador: IEEE
Tipo: Artigo de Revista Científica
Publicado em //2014 Português
Relevância na Pesquisa
36.07%
This letter presents an S-shaped complementary split ring resonator (S-CSRR) for application in compact differential filters. The working principle of the proposed S-CSRR is explained and a circuitmodel is developed and validated through electromagnetic simulations. It is shown that an S-CSRR-loaded differential microstrip line with series gaps can be used in the design of compact differential bandpass filters (BPFs) with common-mode suppression. The filter design procedure is explained and the theoretical concept is validated through fabrication and measurement of a compact (0.09λɡ X 2.25λɡ) third-order differential BPF with common-mode suppression.; Ali K. Horestani, Miguel Durán-Sindreu, Jordi Naqui, Christophe Fumeaux and Ferran Martin

A 26 GHz Phase-Locked Loop Frequency Multiplier in 0.18-um CMOS

Carr, John
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado Formato: 1916222 bytes; application/pdf
Português
Relevância na Pesquisa
36.13%
This thesis presents the analysis, design and characterization of an integrated high-frequency phase-locked loop (PLL) frequency multiplier. The frequency multiplier is novel in its use of a low multiplication factor of 4 and a fully differential topology for rejection of common mode interference signals. The PLL is composed of a voltage controlled oscillator (VCO), injection-locked frequency divider (ILFD) for the first divide-by-two stage, a static master-slave flip-flop (MSFF) divider for the second divide-by-two stage and a Gilbert cell mixer phase detector (PD). The circuit has been fabricated using a standard CMOS 0.18-um process based on its relatively low cost and ready availability. The PLL frequency multiplier generates an output signal at 26 GHz and is the highest operational frequency PLL in the technology node reported to date. Time domain phase plane analysis is used for prediction of PLL locking range based on initial conditions of phase and frequency offsets. Tracking range of the PLL is limited by the inherent narrow locking range of the ILFD, and is confirmed via experimental results. The performance benefits of the fully differential PLL are experimentally confirmed by the injection of differential- and common-mode interfering signals at the VCO control lines. A comparison of the common- and differential-mode modulation indices reveals that a common mode rejection ratio (CMRR) of greater than 20 dB is possible for carrier offset frequencies of less than 1 MHz. Closed-loop frequency domain transfer functions are used for prediction of the PLL phase noise response...

Analysis of intrinsic mode functions: A PDE approach; Analyse des modes empiriques : une approche EDP

DIOP, El Hadji; ALEXANDRE, Radjesvarane; BOUDRAA, Abdel-Ouahab
Fonte: IEEE Publicador: IEEE
Português
Relevância na Pesquisa
36.09%
The empirical mode decomposition is a powerful tool for signal processing. Because of its original algorithmic, recent works have contributed to its theoretical framework. Following these works, some mathematical contributions on its comprehension and formalism are provided. In this paper, the so called local mean is computed in such a way that it allows the use of differential calculus on envelopes. This new formulation makes us prove that iterations of the sifting process are well approximated by the resolution of partial differential equations (PDE). Intrinsic mode functions are originally defined in a intuitive way. Herein, a mathematical characterization of modes is given with the proposed PDE based approach.

Characterization of a Differential Radio-Frequency Single-Electron Transistor

Schneiderman, J. F.; Delsing, P.; Shaw, M. D.; Bozler, H. M.; Echternach, P. M.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 18/07/2005 Português
Relevância na Pesquisa
35.86%
We have fabricated and characterized a new type of electrometer that couples two parallel single-electron transistors (SETs) to a radio-frequency tank circuit for use as a differential RF-SET. We demonstrate operation of this device in summing, differential, and single-SET operation modes, and use it to measure a Coulomb staircase from a differential single Cooper-pair box. In differential mode, the device is sensitive to uncorrelated input signals while screening out correlated ones.; Comment: 3 pages, 3 figures, submitted to Applied Physics Letters

A CMOS 0.8 μm fully differential current mode buffer for HF SI circuits

Rosa, José M. de la; Pérez-Verdú, Belén; Medeiro, Fernando; Domínguez-Castro, R.; Rodríguez-Vázquez, Ángel
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 1238962 bytes; application/pdf
Português
Relevância na Pesquisa
35.98%
El pdf del artículo es la versión post-print.; We present a high-frequency fully-differential current-mode buffer to interface off-chip currents with no significant degradation of the frequency response, and to measure current-mode ICs using standard equipment. It has been fabricated in a 0.8μm double-poly double-metal CMOS technology and features more than 37MHz bandwidth. In order to show its functionality, this unit has been incorporated to the front end of a Switched-Current Band-Pass ΣΔ modulator featuring 9 bit dynamic range at 10MHz clock frequency for a 30kHz signal bandwidth centered at 2.5MHz.; Peer reviewed

Nonlinear Dynamics of Semiconductor Laser Systems with Feedback: Applications to Optical Chaos Cryptography, Radar Frequency Generation, and Transverse Mode Control

Chembo Kouomou, Yanne
Fonte: Universidad de las Islas Baleares Publicador: Universidad de las Islas Baleares
Tipo: Tesis Formato: 2373 bytes; 4909070 bytes; text/plain; application/pdf
Português
Relevância na Pesquisa
35.97%
Tesis doctoral de la Universidad de las Islas Baleares, Facultad de Física y del Departamento de Física Interdisciplinar del Instituto Mediterráneo de Estudios Avanzados (IMEDEA-CSIC/UIB).-- Fecha de lectura: 15-12-2006.; The simple fact to introduce and account for a delay time in a dynamical system increases its dimensionality to infinity, and thereby opens the way to a wide variety of very complex behaviors. Despite the huge advances of physics and mathematics in the twentieth century, in is only at the early sixties that delay differential equations gained sufficient attention from the scientific community. In the first years, though, the interest was purely mathematical and these equations where studied under the terminology of Functional Differential Equations, mainly by Krasovskii and Hale. Then, these new ideas rapidly started to spread in various areas of applied science, particularly in control theory. In physics, in particular, delay differential equations have been found to be the idoneous tool to investigate the behavorial properties of dynamical systems where delays had to be taken into account. Far beyond the scope of physics, delay differential systems have been successfully used to investigate a very large spectrum of problems...

Symmetry properties in transmission lines loaded with electrically small resonators circuit modeling and application to common-mode suppressed differential lines, microwave sensors, and spectral signature barcodes

Naqui Garolera, Jordi
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 Formato: application/pdf
Publicado em //2014 Português
Relevância na Pesquisa
36.07%
Esta tesis se centra en el análisis, modelado circuital y aplicaciones de líneas de transmisión cargadas con resonadores eléctricamente pequeños (por ejemplo, resonadores de anillos abiertos -SRR- o resonadores de salto de impedancia -SIR-) sujetos a consideraciones de simetría. Los resultados obtenidos en esta tesis expanden el estado del arte en el marco de líneas de transmisión cargadas con resonadores i líneas de transmisión basadas en metamateriales. Por esta razón, primero revisamos la teoría fundamental de metamateriales y resonadores eléctricamente pequeños. A continuación presentamos algunos avances en los modelos circuitales equivalentes con elementos concentrados de líneas de transmisión cargadas con resonadores basados en metamateriales: (a) modelamos el acoplamiento magnetoeléctrico entre la línea de transmisión y los resonadores, dado que éste se debe tener en cuenta dependiendo de la orientación relativa entre la línea y los resonadores, particularmente cuando la estructura es simétrica en el plano medio; (b) aplicando la teoría de estructuras periódicas infinitas utilizando matrices de transmisión de cuatros puertos, mostramos que el acoplamiento entre resonadores en líneas de transmisión cargadas con resonadores aumenta el ancho de banda de rechazo debido a la aparición de modos complejos; e (c) inferimos los límites en el rango de valores de inductancia y capacidad que se pueden implementar de resonadores serie conectados en derivación por medio de stubs en derivación de salto de impedancia. Después...

Coupled-mode theory for Bose-Einstein condensates

Ostrovskaya, Elena; Kivshar, Yuri; Lisak, Mietek; Hall, Bjorn; Cattani, Frederica; Anderson, D L
Fonte: American Physical Society Publicador: American Physical Society
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
35.83%
The mode coupling and intermodal population exchange in traped Bose-Einstein Condensations (BECs) were analyzed. The BEC dynamics in a harmonic double-well potential were considered, and the dynamical coupled-mode equations were derived. A threshold of the condensate fragmentation was identified.