Axisymmetric modal analysis of liquid‐storage tanks considering compressibility effects

In this paper, we address analytical and numerical studies on the free vibration of fluid–structure interaction problems considering the fluid compressibility. According to the separation of variables together with the boundary condition enforcement, we first derive a compressible‐fluid velocity potential function. Next, we split the structure region into the wet and dry parts, for which we apply the Novozhilov thin shell theory. Combining two dynamic displacement fields, for two split structure parts, using the displacement compatibility conditions, we finally obtain a simultaneous equation system for computing natural frequencies and modes. According to the derived analytical formulae, we compute natural frequencies and modes, stress resultants, together with the comparison with the FEM analysis and the incompressible case. Numerical results show, compared to the incompressible case, that the compressible case produces lower natural frequencies and, furthermore, the relative difference is influenced by the slenderness of tanks and the relative liquid fill height. Copyright © 2002 John Wiley & Sons, Ltd.     

Dopant-free FUSI Pt/sub x/Si metal gate for high work function and reduced Fermi-level pinning

High work function (4.9 eV) on high-/spl kappa/ gate dielectric, which is suitable for bulk p-MOSFET, has been achieved using fully silicided (FUSI) Pt/sub x/Si gate without boron predoping of polysilicon. High concentration of Pt in FUSI Pt/sub x/Si using Ti capping layer on Pt in the FUSI process is a key to achieving high work function and reduced Fermi-level pinning on high-/spl kappa/ dielectric. By combining with substituted Al (SA) gate for nMOSFET, a wide range of work function difference (0.65 eV) between n and pMOSFETs is demonstrated, without any adverse effects of polysilicon predoping.     

High-power long-wavelength (λ~11.5 μm) quantum cascadelasers operating above room temperature

High-temperature operation (T=320 K) of quantum cascade lasers has been extended to 11.5-μm wavelengths with high performances. Peak-pulsed optical power of 55 mW is obtained at 300 K with a high T ₀=172 K, in good agreement with our theoretical model     

Dependence of the linewidth enhancement factor on the number of compressively strained quantum well in lasers

We have systematically studied the well number dependence of the linewidth enhancement factor in strained quantum-well (QW) lasers and have demonstrated experimentally that the linewidth enhancement factor can be reduced from /spl sim/9.4 to /spl sim/2.0 by increasing the number of compressively strained QW's from 2 to 8. This behavior is primarily due to an increase in the differential gain with the number of QW's.     

Performance assessment through bootstrap

A new performance evaluation paradigm for computer vision systems is proposed. In real situation, the complexity of the input data and/or of the computational procedure can make traditional error propagation methods infeasible. The new approach exploits a resampling technique recently introduced in statistics, the bootstrap. Distributions for the output variables are obtained by perturbing the nuisance properties of the input, i.e., properties with no relevance for the output under ideal conditions. From these bootstrap distributions, the confidence in the adequacy of the assumptions embedded into the computational procedure for the given input is derived. As an example, the new paradigm is applied to the task of edge detection. The performance of several edge detection methods is compared both for synthetic data and real images. The confidence in the output can be used to obtain an edgemap independent of the gradient magnitude     

Characteristics of body-tied triple-gate pMOSFETs

Body-tied triple-gate pMOSFETs were fabricated using bulk Si wafers and characterized. Process steps to implement the devices are explained briefly. Device characteristics of the triple-gate pMOSFETs were compared with those of the conventional planar channel device. While maintaining low off-leakage currents and threshold voltages similar to those of planar pMOSFETs in the parallel arrayed 30 000 transistors, the body-tied triple-gate MOSFETs showed about 74 mV/dec of subthreshold swing (92 mV/dec for conventional devices) and a drain-induced barrier lowering of 34 mV/V (92 mV/V for conventional devices). It was also addressed that I/sub SUB//I/sub D/ of the body-tied triple-gate is lower than that of the planar channel device.     

A study on the temperature dependence of epoxy/BaTiO<Subscript>3</Subscript> composite embedded capacitor films

In this study, the temperature dependence of capacitance, one of the most important properties of embedded capacitor films (ECFs), was investigated. The temperature dependence of the capacitance of ECFs was determined by the temperature dependence of the dielectric constant and thickness, and among these, the main factor was the dielectric constant of ECFs. The dielectric constant of ECFs was determined by that of epoxy and BaTiO₃ powders. Below 130°C, the dielectric constant of ECFs increased as temperature increased, and was mainly affected by an epoxy matrix. However, above 130°C (the Curie temperature of BaTiO₃), the increased rate of the dielectric constant of ECFs started decreasing. This was due to the fact that BaTiO₃ powder undergoes a phase transition from a tetragonal to a cubic structure, and its dielectric constant decreases at 130°C. The dielectric constant of BaTiO₃ powder was obtained from measured dielectric constants of ECF and application of the Lichtenecker logarithmic rule.