Papers by Keyword: Transfer Matrix Method

Abstract: Hollow-pillar phononic metamaterials (PM) operating at the whispering gallery modes can be modulated by external rotation, and they exhibit the band splitting linearly related to the angular rate. This phenomenon holds great potential for applications in angular velocity measurement and dynamically adaptive noise reduction. In this paper, we establish an equivalent model for the interaction between elastic waves and such periodic PM. By combining dynamic coupling equations with the transfer matrix method, we theoretically reveal the existence of rotation-induced band splitting and explain its causes. Further validation of the band splitting theory is achieved through comparison with finite element simulation results. This study serves as a theoretical supplement to these rotation-modulated PM, elucidating the mechanism of how external rotation affects band splitting at a theoretical level and inspiring the development of more similar dynamically adaptive materials.

Abstract: Metallic nanoparticle-based material is currently implemented in many photonics-based applications such as biosensors, imaging, and color filter due to its remarkable properties called localized surface plasmon or LSP. Numerical methods are commonly used to calculate the optical responses arising from the nanostructure. However, a faster calculation can be provided by analytical methods. In this paper, we used an analytical calculation based on dipolar approximation and the transfer matrix method to calculate the optical responses of stacked-nanoparticles array on a dielectric substrate. Gold (Au) and silver (Ag) nanoparticles embedded inside a dielectric medium are considered. To validate the results, the analytical model was benchmarked to a finite element method (FEM) calculation. We found that the absolute difference of the absorbance peak of the analytical model to FEM calculation is less than 2 nm with the volume fraction of ~20% and it becomes better with a lower volume fraction. The field distribution analysis shows that lower volume fraction structures lead to weaker near-field coupling, therefore concluding that the analytical model is suitable only for sparse structure. Experimental data also can be replicated from the spectral profile showing opportunities to use the analytical model in the application design stage.

Abstract: We simulate quantum mechanical tunneling current in armchair graphene nanoribbon tunnel field-effect transistors (AGNR-TFETs). The relativistic Dirac equation is used to determine electron wave functions in the AGNRs, while the potential profile is solved by the Poisson equation. We use a transfer matrix method (TMM) to calculate the electron transmittance and the Dirac electron tunneling current in the AGNR-TFETs. The results show that the Dirac electron tunneling current increases with increasing the drain and gate voltages. Moreover, the AGNR width and the thickness of insulator affect the characteristics of the Dirac electron tunneling currents.

Abstract: Exhaust noise is one of the noise pollution to the environment and it will cause interference that may harm the activity or balance of human. A muffler is designed to minimize transmission caused by exhaust gases. In this paper, the principle of transfer matrix method is used to analyze the transmission loss. The method is used for developed source code programming to predict muffler performance. The result from programming show excellent agreement with the previous established research paper. This programming is applied for baffle effect to determine transmission loss.

Abstract: To further investigate the mechanism of the interaction between the response of single pile and pile-soil on the condition of lateral load, on the basis of the normal type of the coefficient of subgrade reaction, this paper reaches the transfer matrix solution of single pile subject to lateral load by combining matrix transfer method with finite element method assuming that the coefficient of subgrade reaction is constant in each finite element. With the matrix solutions obtained, a computer program is developed using MATLAB to compute the pile responses and parametric studies are carried out on the effect of the constraint conditions of pile head and tip, effect of soil properties etc. and the results are discussed in detail.

Abstract: To simplify the model of rotating cylindrical shell, the static forces are neglected and the vibration equations are established. Transfer matrix method is used to solve the equations and the example shows that the simplified model has little effect on the result. So the simplified model can be used in complex structures such as multilayer and multidiameter shell.

Abstract: The article deals with the simplified calculation of the stiffness of the eccentric press frame. The described method applies to the solving of problem a mathematical identification of condition parameters in the press frame the transfer matrix method (TMM), which is in essence a matrix form of initial parameters method. This method is suitable for mechanical systems with continuously distributed mass in space while the cross-sections along the entire length of the system are not constant.

Abstract: Cantilevered shaft-rotor systems consisting of multi disks and multi profiled shafts are considered. In this paper the procedures for the determination of the deflection, slope, shear force and bending moment at the extremities of the shaft are employed. Critical speeds or whirling frequency conditions are computed using transfer matrix method (TMM). For particular shaft-lengths, rotating speeds and shaft-profiles, the response of the system is determined for the establishment of the dynamic characteristics. A built-in shaft-rotor system consisting of two disks and two different profiled shafts is investigated for illustration purposes. Step response of the multi profiled shaft-rotor system is also found out.

Abstract: We have studied tunneling current in a p-n junction based on armchair graphene nanoribbon (AGNR) by using the relativistic Dirac equation and a transfer matrix method (TMM). The electron wave function was derived by solving the relativistic Dirac equation. The TMM, which is a numerical approach, was used to calculate electron transmittance and the tunneling current. The results showed that the tunneling current increases with the bias voltage. On the other hand, the tunneling current increases with the decreases in the electron incidence angle and temperature. Moreover, the increases in the AGNR width and electric field in the p-n junction result in the increase in the tunneling current.