High-quality isosurface generation using an oversampling method

Isosurface generation from medical images was done using an oversampling method. The key idea of the proposed method was based on the fact that oversampling and downsampling together can improve the signal-to-noise (SNR) ratio. The procedure consisted of four phases: (1) oversampling of a voxel, (2) topology estimation, (3) low-pass filtering, and (4) downsampling. The effectiveness of the method was verified in terms of SNR, compactness, and surface roughness of the fabricated rapid prototyping parts.     

Analysis of combustion and flame propagation characteristics of LPG and Gasoline fuels by laser deflection method

This work is to investigate the combustion characteristics and flame propagation of the LPG (liquified petroleum gas) and gasoline fuel. In order to characterize the combustion processes of the fuels, the flame propagation and combustion characteristics were investigated by using a constant volume combustion chamber. The flame propagation of both LPG and gasoline fuels was investigated by the laser deflection method and the high-speed Schlieren photography. The result of laser deflection method show that the error of measured flame propagation speed by laser method is less than5% compared with the result of high-speed camera. The flame propagation speed of the fuel is increased with the decrease of initial pressure and the increase of initial temperature in the constant volume chamber. The results also show that the equivalence ratio has a great effect on the flame speed, combustion pressure and the combustion duration of the fuel-air mixture.     

Dynamic behaviors of an elastically restrained beam carrying a moving mass

Dynamic responses of a simply supported beam with a translational spring carrying a moving mass are studied. Governing equations of motion including all the inertia effects of a moving mass are derived by employing the Galerkin’s mode summation method, and solved by using the Runge-Kutta integral method. Numerical solutions for dynamic responses of a beam are obtained for various cases by changing parameters of the spring stiffness, the spring position, the mass ratio and the velocity ratio of a moving mass. Some experiments are conducted to verify the numerical results obtained. Experimental results for the dynamic responses of the test beam have a good agreement with numerical ones.     

Dynamic responses and fuzzy control of a simply-supported beam subjected to a moving mass

This paper deals with the active vibration control of a simply-supported beam traversed by a moving mass using fuzzy control. Governing equations for dynamic responses of a beam under a moving mass are derived by Galerkin’s mode summation method, and the effect of forces (gravity force, Coliolis force, inertia force caused by the slope of the beam, transverse inertia force of the beam) due to the moving mass on the dynamic response of a beam is discussed. For the active control of dynamic deflection and vibration of a beam under the moving mass, the controller based on fuzzy logic is used and the experiments are conducted by VCM (voice coil motor) actuator to suppress the vibration of a beam. Through the numerical and experimental studies, the following conclusions were obtained. With increasing mass ratioy at a fixed velocity of the moving mass under the critical velocity, the position of moving mass at the maximum dynamic deflection moves to the right end of the beam. With increasing velocity of the moving mass at a fixed mass ratioy, the position of moving mass at the maximum dynamic deflection moves to the right end of the beam too. The numerical predictions of dynamic deflection of the beam have a good agreement with the experimental results. With the fuzzy control, more than 50% reductions of dynamic deflection and residual vibration of the tested beam under the moving mass are obtained.     

Seed crystal of modified potassium sodium niobate prepared by simple molten salt synthesis

Recently, an interesting phenomenon has been reported in (K,Na)NbO₃ (KNN)‐based ceramics. That is the growth of huge grains (10‐30 mm) which is a kind of abnormal grain growth (AGG). It was also interesting that the huge grains showed the stack of plate‐type grains. Using one of those compositions, therefore, seed plates were synthesized by not topochemical reaction but simple molten salt synthesis (SMSS) which was a simple‐and‐cheap process. The calcined K_0.4925Na_0.4925Ba_0.0165Nb_0.998O_3.004 (KNBN) powders and KF powders were heat‐treated at 1050°C‐1150°C. The seed crystals showed the (100)_C‐oriented structure. The size of seed plates was smaller than 500 μm and one layer of a thin plate‐type grain might show the thickness of 50 nm. They might be useful as the seeds at RTGG or TGG process.     

Mask-substrate gap control system for exposure equipment

Microsystem Technologies - Precise printed circuit boards (PCBs) and touch screen panels (TSPs) are produced by the proximity exposure patterning process. In the exposure patterning process, the...     

Preparation and characterization of chromium oxide supported on zirconia

Chromium oxide/zirconia was prepared by dry impregnation of powdered Zr(OH)₄ with an aqueous solution of (NH₄)₂CrO₄. The characterization of prepared samples was performed using Fourier-transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and differential thermal analysis (DTA), and by measurement of the surface area. The addition of chromium oxide to zirconia shifted the transitions of ZrO₂ from the amorphous to the tetragonal phase and from the tetragonal to the monoclinic phase to higher temperatures due to the strong interaction between chromium oxide and zirconia; and the specific surface area of the samples increased in proportion to the chromium-oxide content. Since the ZrO₂ stabilizes supported chromium oxide, chromium oxide was well dispersed on the surface of zirconia, and -Cr₂O₃ was only observed at calcination temperatures above 1173 K. Upon the addition of only small amounts of chromium oxide (1 wt % Cr) to ZrO₂, both the acidity and acid strength of the samples increased remarkably, showing the presence of two kinds of acid sites on the surface of CrOx/ZrO₂ (Brönsted and Lewis acid sites).     

Charge Transfer to LaAlO3/SrTiO3 Interfaces Controlled by Surface Water Adsorption and Proton Hopping

Electronic properties of low dimensional systems are particularly sensitive to surface adsorbates. Clear understanding of such phenomena can lead to highly effective and nondestructive material engineering techniques. In this work, water adsorption at the surface of LaAlO₃/SrTiO₃ heterostructures is systematically studied. The saturation of surface dangling bonds by spontaneous water chemisorptions is found to be a main enabler of the formation of the interface 2D electron gas. In particular, when imbalanced distributions of water based ions, namely protons and hydroxyls, are generated, interface electron doping or depletion becomes surface adsorbates dominant and independent of the LaAlO₃ layer thickness. The investigations also reveal the importance of hydrogen bonding through molecular water layers, which provides an energetically feasible pathway for manipulating the surface‐bond protons and thus the interface electrical characteristics.