Artigos Técnicos e Apresentações

Aqui você encontrará apresentações realizadas nas Conferências de Usuários COMSOL de todo o mundo. As apresentações englobam pesquisas e produtos inovadores feitas por engenheiros e cientistas usando o COMSOL Multiphysics. Os tópicos abramgem uma grande gama de indústrias e aplicações, como elétrica, mecânica, escoamento e química. Use a função de busca "Quick Search" para encontrar apresentações na sua área de interesse.

Numerical Study of Exciton States of Core?shell CdTe/CdS Nanotetrapods by using COMSOL Multiphysics

Y. Yao?and K. Sakoda
National Institute for Materials Science
University of Tsukuba

This paper showed: * The electronic states of core-shell tetrapod with various shell thickness were calculated. Lowest 20 electron and hole wave functions have A1 or T2 symmetry. * At t=1.2 nm, the carriers separation is not serious, core-shell tetrapod is not apparent type II heterostructure. * Exciton states were investigated as a function of t. For large t, the lowest exciton state has T2 ...

Mechanical Model of RF MEMS Capacitor Structures

R. Chatim[1]
[1]University of Kassel, Kassel, Germany

In order to design an RF MEMS based device, it is beneficial to have information concerning mechanical behavior. For model verification purpose, solution offered by simulation software equipped with predefined physics application is one valuable way to provide initial reference. To avoid unwanted particular total strain in RF MEMS structures, a compensation layer can be utilized. When the number ...

3D Stationary and Temporal Electro-Thermal Simulations of Metal Oxide Gas Sensor Based on a High Temperature and Low Power Consumption Micro-Heater Structure

N. Dufour[1], C. Wartelle[2], P. Menini[1]
[1]LAAS-CNRS, Toulouse, France
[2]Renault, Guyancourt, France

The aim of this work was to simulate the electro-thermal behavior of a micro-hotplate used as a gas sensor, in order to compare the obtained results with a real structure. The structure has been designed in 3D and a stationary and a temporal study has been realized.

Simple Finite Element Model of the Topografiner

H. Cabrera[1], D. A. Zanin[1], L. G. De Pietro[1], A. Vindigni[1], U. Ramsperger[1], D. Pescia[1]
[1]Laboratory for Solid State Physics, ETH Zürich, Zürich, Switzerland

In our recent experiments we are revisiting the topografiner technology for the imaging of surface topography with a resolution of a few nanometers. In these new technique called Near-Field Emission Scanning Electron Microscopy (NFESEM), low-energy electrons are emitted from a polycrystalline tungsten tip via electric-field assisted tunneling. In order to characterize and improve the capabilities ...

Generalized Plane Piezoelectric Problem: Application to Heterostructure Nanowires

H. T. Mengistu[1], A. García-Cristóbal[1]
[1]Material Science Institute, University of Valencia, Valencia, Spain

The possibility to dispose of two-dimensional (2D) approaches to problems originally posed in a three-dimensional (3D) geometry is always desirable since it reduces significantly the computing resources needed for numerical studies. In this work we report on a new 2D approach called Generalized Plane Piezoelectric (GPP) problem [1] and apply it to the calculation of the strain and electric fields ...

FEM Study on Contactless Excitation of Acoustic Waves in SAWDevices

A. K. Namdeo[1], N. Ramakrishna[2], H. B. Nemade[1,2], and R. P. Palathinkal[1]

[1] Department of Electronics and Communication Engineering, Indian Institute of Technology Guwahati, Assam, India
[2] Centre for Nanotechnology. Indian Institute of Technology Guwahati, Assam, India

In this paper a finite element method(FEM) study of a surface acoustic wave (SAW)device excited by electrostatic coupling method is performed by using COMSOL Multiphysics. We have modeled a Rayleigh wave type SAW device by choosing YZ Lithium niobate as the substrate. The effect of external radio frequency (RF) field to the SAW device is analyzed. The effect of distance between the contactless ...

High Coupling Factor Piezoelectric Materials for Bending Actuators: Analytical and Finite Elements Modeling Results

I.A. Ivan[1], M. Rakotondrabe[1], and N. Chaillet[1]
[1]FEMTO-ST Institute, University of Franche-Comte, Besançon, France

New giant piezoelectric factor materials such as PMN-PT and PZN-PT were researched during the last decade and are actually becoming commercially available. As they seem very attractive for actuator designs, we studied their potential in replacing PZT ceramics. In a first comparative approach, we tested a series of classic rectangular composite bimorph structures of different combinations of ...

Interfacing Continuum and Discrete Methods: Convective Diffusion of Microparticles and Chemical Species in Microsystems

J. Berthier
CEA-LETI, Department of Biotechnology, Grenoble, France

Convective transport of macromolecules or micro and nanoparticles in microsystems are usually predicted by solving the Navier Stokes equations for the carrier fluid and a concentration equation for the diffusing species. In the case of isolated particles or complicated geometries with extremely small apertures or microporous material, the concentration equation maybe replaced by a Monte Carlo ...

Strong Magnetic Field and Its Application

Y. Song
Huazhong University of Science and Technology, Wuhan, China

High magnetic field research has yielded fruitful results. Since 1913, associated with the magnetic field there are 19 Nobel Prizes, including a prize for medicine, five chemistry prizes, and 13 physics prizes. In recent years, the international community under the conditions of strong magnetic field is very active in scientific research, involving many disciplines such as physics, chemistry, ...

Efficient Generation of Surface Plasmon Polaritons with Asymmetric Nano-structures

J. Chen
Peking University

This paper covers the following: * All-Optical Light Modulation of surface plasmon polaritons (SPPs) is achieved using asymmetric single nanoslits. A high on/off switching ratio of >20 dB and phase variation of >? were observed with the device lateral dimension of only about 2 ?m. * Efficient unidirectional excitation of SPP as well as beam splitting are achieved using the ...

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