Payam Sharifi¹, Asghar Esmaeeli²

FDMP-Fluid Dynamics & Materials Processing, Vol.9, No.4, pp. 389-418, 2013, DOI:10.3970/fdmp.2013.009.389

Abstract This study aims to explore the effect of liquid film thickness on the electrohydrodynamic-driven instability of the interface separating two horizontal immiscible liquid layers. The fluids are confined between two electrodes and the light and less conducting liquid is overlaid on the heavy and more conducting one. Direct Numerical Simulations (DNSs) are performed using a front tracking/finite difference scheme in conjunction with Taylor-Melcher leaky dielectric model. For the range of physical parameters used here, it is shown that for a moderately thick lower liquid layer, the interface instability leads to formation of several liquid columns… More >

Yongze Cao¹, Guojian Li¹, Qiang Wang^1,2, Xiaoguang Wang³, Jiaojiao Du¹, Jicheng He¹

CMC-Computers, Materials & Continua, Vol.37, No.3, pp. 195-203, 2013, DOI:10.3970/cmc.2013.037.195

Abstract The Fe₆₀Ni₄₀ (in atomic %) polycrystalline thin films with 90 nm thickness were prepared on 200 °C quartz substrate by using molecular beam vapor deposition method. The influence of 0 T and 6 T magnetic fields on the structural evolution and magnetic properties of thin films was studied by using EDXS, XRD, AFM and VSM. In this study, only α phase was formed in both thin films. It was found that the application of a 6 T magnetic field obviously decreases the RMS of surface roughness and the grain size. For the magnetic properties of the More >

Jiaojiao Du¹, Guojian Li¹, Qiang Wang^1,2, Yongze Cao¹, Jicheng He¹, Yonghui Ma¹

CMC-Computers, Materials & Continua, Vol.34, No.2, pp. 117-129, 2013, DOI:10.3970/cmc.2013.034.117

Abstract The effects of high magnetic field and post-annealing on the structural, electrical and magnetic properties of the evaporated Ni films were investigated and compared. The in-situ application of a 6 T magnetic field during evaporation or post-annealing at 200°C did not change the crystal structures of the films. However, the magnetic field makes the films exhibit the smallest grain size and the lowest surface roughness. Crystallinity was improved for both the 6 T films and the annealed films. This leads to the enhancement of saturation magnetization (Ms). The value of Ms for the 0 T More >

Yunpeng Ren, J. K. Chen^*, Yuwen Zhang

Frontiers in Heat and Mass Transfer, Vol.3, No.2, pp. 1-7, 2012, DOI:10.5098/hmt.v3.2.3001

Abstract Heat transfer in a copper film irradiated by a femtosecond (fs) laser pulse train and by an integrated dual laser beam of a nanosecond pulse with a fspulse train was studied using the semi-classical two-temperature model. The critical point model with three Lorentzian terms was employed to characterize transient optical properties for the laser energy deposition. The effects of pulse number and separation time on the thermal response were investigated. The results showed that with the same total energy in a fs-pulse train, more pulses for shorter separation time, e.g., 1 ps, and fewer pulses More >

Donggang Li^1,2, Alexandra Levesque², Qiang Wang^1,3,2, Agnieszka Franczak², Chun Wu¹, Jean-Paul Chopart², Jicheng He¹

CMC-Computers, Materials & Continua, Vol.30, No.3, pp. 207-218, 2012, DOI:10.3970/cmc.2012.030.207

Abstract Co/Ni bilayered films were prepared on ITO glass by electrodeposition assisted with a magnetic field up to 0.5T aligned parallel to the electrode surface. The effect of a high magnetic field annealing up to 12T on morphology and microstructure of the post-deposited films was investigated by field emission scanning electronic microscopy (FE-SEM), X-ray diffraction (XRD) and atomic force microscopy (AFM). Grain shape and grain boundary in the Co/Ni morphology were modified dramatically when the high magnetic field was applied during the annealing process. Magnetic anisotropy appeared in the films due to the preferential orientation of More >

Georg F. Dietze^†, Reinhold Kneer

Frontiers in Heat and Mass Transfer, Vol.2, No.3, pp. 1-14, 2011, DOI:10.5098/hmt.v2.3.3001

Abstract Despite the use of liquid films in a wide variety of technical applications involving heat and mass transfer (e.g. nuclear reactors, cooling towers and gas turbines), where they often play an important role, the underlying momentum and heat transport processes within these thin liquid layers remain to be fully elucidated. In particular, this applies to the influence that surface waves, developing due to the film’s natural instability, exert on the mentioned processes. In this context, it has been suggested by several experimental and numerical observations that momentum and heat transfer in the capillary wave region… More >

Jing Huang, Kapil Baheti, J. K. Chen^*, Yuwen Zhang

Frontiers in Heat and Mass Transfer, Vol.2, No.1, pp. 1-10, 2011, DOI:10.5098/hmt.v2.1.3005

Abstract An axisymmetric model for thermal transport in thin metal films irradiated by an ultrashort laser pulse was developed. The superheating phenomena including preheating, melting, vaporization and re-solidification were modeled and analyzed. Together with the energy balance, nucleation dynamics was employed iteratively to track the solid-liquid interface and the gas kinetics law was used iteratively to track the liquid-vapor interface. The numerical results showed that higher laser fluence and shorter pulse width lead to higher interfacial temperature, larger melting and ablation depths. A simplified 1-D model could overestimate temperature response and ablation depth due to the More >

Dennis Bäcker¹, Andreas Ricoeur², Meinhard Kuna¹

Structural Durability & Health Monitoring, Vol.7, No.1&2, pp. 1-22, 2011, DOI:10.3970/sdhm.2011.007.001

Abstract A new sensor concept for monitoring fatigue crack growth in technical structures is presented. It allows the in-situ determination of the position of the crack tip as well as the fracture mechanical quantities. The required data are obtained from a piezoelectric polymer film, which is attached to the surface of the monitored structure. The stress intensity factors and the crack tip position are calculated from electrical potentials obtained from a sensor array by solving the non-linear inverse problem. More >

Yifan Xia, Jie Wang

The International Conference on Computational & Experimental Engineering and Sciences, Vol.20, No.3, pp. 87-88, 2011, DOI:10.3970/icces.2011.020.087

Abstract Phase field simulation is an effective way to predict the domain evolution in ferroelectric materials. A phase field model is developed to investigate the domain structures and polarization switching in in ferroelectric thin films with deadlayers. Simulation results show that the deadlayers as well as misfit strain have a significant influence on the domain structures and polarization switching in the ferroelectric thin films. It is found that the simulated switching electric field in ferroelectric thin films decreases with the thickness of the deadlayers increasing. More >

S. H. Kwon¹, B. R. Kim², H. K. Lee^2,3

CMC-Computers, Materials & Continua, Vol.21, No.1, pp. 65-86, 2011, DOI:10.3970/cmc.2011.021.065

Abstract The electromagnetic shielding effectiveness of grid-mesh films made of polyaniline was numerically investigated, and the optimal size of the polyaniline grid was determined through numerical analyses. The permittivity of polyaniline was first determined from an inverse analysis based on experimental data. A series of numerical analyses were carried out with 225 polyaniline grid-mesh films of different thickness, spacing, and width, and the shielding effectiveness of every grid was examined. In addition to the numerical analysis, the transparency of the grid-mesh films and the amount of polyaniline material required to manufacture the unit grid area (1mx1m) More >