• Wind and Structures
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• v.22 no.4
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• pp.429-454
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• 2016

In this paper, a shear deformation plate theory based on neutral surface position is developed for free vibration analysis of functionally graded material (FGM) plates. The material properties of the FGM plates are assumed to vary through the thickness of the plate by a simple power-law distribution in terms of the volume fractions of the constituents. During manufacture, defects such as porosities can appear. It is therefore necessary to consider the vibration behavior of FG plates having porosities in this investigation. The proposed theory is based on assumption that the in-plane and transverse displacements consist of bending and shear components, in which the bending components do not contribute toward shear forces and, likewise, the shear components do not contribute toward bending moments. The neutral surface position for a functionally graded plate which its material properties vary in the thickness direction is determined. The equation of motion for FG rectangular plates is obtained through Hamilton's principle. The closed form solutions are obtained by using Navier technique, and then fundamental frequencies are found by solving the results of eigenvalue problems. Numerical results are presented and the influences of the volume fraction index and porosity volume fraction on frequencies of FGM plates are clearly discussed.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.9
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• pp.1335-1344
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• 2015

A set of prediction equations to estimate the nitrogen-corrected apparent metabolizable energy (AMEn) of individual ingredients and diets used in the poultry feed industry was evaluated. The AMEn values of three energy ingredients (maize, sorghum and defatted maize germ meal), four protein ingredients (soybean meal, maize gluten meal 60% crude protein, integral micronized soy and roasted whole soybean) and four diets (three containing four feedstuffs, complex diets, and one containing only corn-soybean meal, basal diet) were determined using a metabolism assay with male broilers from 1 to 7, 8 to 21, 22 to 35, and 36 to 42 days old. These values were compared to the AMEn values presented in the tables of energy composition or estimated by equation predictions based on chemical composition data of feedstuffs. In general, the equation predictions more precisely estimated the AMEn of feedstuffs when compared to the tables of energy composition. The equation AMEn (dry matter [DM] basis) = 4,164.187+51.006 ether extract (% in DM basis)-197.663 ash-35.689 crude fiber (% in DM basis)-20.593 neutral detergent fiber (% in DM basis) ($R^2=0.75$) was the most applicable for the prediction of the energy values of feedstuffs and diets used in the poultry feed industry.

• Journal of the Korean Applied Science and Technology
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• v.8 no.1
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• pp.1-7
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• 1991

The kinetic of hydrolysis for cinnamylidene aniline derivatives has been investigated by ultraviolet spectrophotometry in 20% (v/v) dioxane - $H_2O$ at $25^{\circ}C$. A rate equation which can be applied over wide pH range was obtained. The substituent effects on cinnamylidene aniline derivatives were studied and the hydrolysis was facilitated by electron attracting group. Final products of the hydrolysis were cinnamaldehyde and aniline. From the rate equation, substituent effect and final products, the hydrolysis of cinnamylidene aniline derivatives was initiated by the neutral molecule of $H_2O$ which does not dissociate at below pH 9.0${\sim}$12.0, but proceeded by the hydrogen ion at above pH 5.0${\sim}$9.0.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.6
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• pp.772-778
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• 2002

A numerical analysis of turbulent gas-particle two-phase flow is performed in conjunction with the experiments of Fackrell ＆ Robins and Raupach & Legg that considered ground-level source and/or elevated source flat plate flow. K-$\omega$ turbulence model is used in order to analyze fully turbulent flow field and the concentration equation with settling velocity is adopted for the concentration field. The model of Einstein and Chien is applied that couples the velocity field and the concentration field. Turbulent eddy viscosity is re-evaluated in this model. The present numerical results have good agreement between the simulation and the experimental data for the mean flow velocities and particle concentrations. While the previous study shows about 27% error in the vicinity of the source of particle concentration, the .present study allows about 14% error. A new turbulent gas-particle flow model developed by this study is able to cut down error by 13% at a near source.

• Structural Engineering and Mechanics
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• v.40 no.4
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• pp.563-581
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• 2011

Many novel materials, developed in recent years, have obvious properties with different modulus of elasticity in tension and compression. The ratio of their tensile modulus to compressive modulus is as high as five times. Nowadays, it has become a new trend to study the mechanical properties of these bimodular materials. At the present stage, there are extensive studies related to the strength analysis of bimodular structures, but the investigation of the buckling stability problem of bimodular rods seems to cover new ground. In this article, a semi-analytical method is proposed to acquire the buckling critical load of bimodular slender rod. By introducing non-dimensional parameters, the position of neutral axis of the bimodular rod in the critical state can be determined. Then by combining the phased integration method, the deflection differential equation of bimodular pin-ended slender rod is deduced. In addition, the buckling critical load is obtained by solving this equation. An example, which is conducted by comparing the calculation results between the three of the methods including the laboratory tests, numerical simulation method and the method we developed here, shows that the method proposed in the present work is reliable to use. Furthermore, the influence of bimodular characteristics on the stability is discussed and analyzed.

• Journal of the Korean Applied Science and Technology
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• v.8 no.2
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• pp.175-181
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• 1991

The kinetics of the addition of 1-benzylindole-3-(p-substituted) acetophenone derivatives was investigated by ultraviolet spectrophotometery in 30% dioxane -$H_2O\;at\;25^{\circ}C$. A rate equation which can be applied over wide pH range was obtained. The Substituent effects on 1-benzylindole-3-(p-substituted) acetophenone derivatives were studied, and addition were facilitated by electron attracting groups. On the base of the rate equation, substituent effect, and general base effect the plausible addition mechanism was proposed : Below pH 3.0, only neutral thiourea molecule was added to the carbon-carbon double bond, and in the range of pH 0.0${\sim}$14.0, netural thiourea molecule and thiourea anion competitively attacted the double bond. By contrast, above pH 10.0, the reaction was dependent upon only the addition of thiourea anion.

• Journal of the Semiconductor & Display Technology
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• v.8 no.3
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• pp.31-37
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• 2009

This paper presents one and two dimensional simulation results with discontinuous features (shocks) of capacitively coupled rf plasmas. The model consists of the first two and three moments of the Boltzmann equation for the ion and electron fluids respectively, coupled to Poisson's equation for the self-consistent electric field. The local field and drift-diffusion approximations are not employed, and as a result the charged species conservation equations are hyperbolic in nature. Hyperbolic equations may develop discontinuous solutions even if their initial conditions are smooth. Indeed, in this work, secondary electron emission is shown to produce transient electron shock waves. These shocks form at the boundary between the cathodic sheath (CS) and the quasi-neutral (QN) bulk region. In the CS, the electrons emitted from the electrode are accelerated to supersonic velocities due to the large electric field. On the other hand, in the QN the electric field is not significant and electrons have small directed velocities. Therefore, at the transition between these regions, the electron fluid decelerates from a supersonic to a subsonic velocity in the direction of flow and a jump in the electron velocity develops. The presented numerical results are consistent with both experimental observations and kinetic simulations.

• Journal of the Korean Physical Society
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• v.73 no.12
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• pp.1855-1862
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• 2018

A reliable set of low-energy electron collision cross sections for the triethoxysilane (TRIES) molecule was derived based on the measured electron transport coefficients for a pure TRIES molecule by using an electron swarm method and a two-term approximation of the Boltzmann equation. The electron transport coefficients calculated using the derived set are in good agreement with experimental value over a wide range of E/N values (ratio of the electric field E to the neutral number density N). The present electron collision cross section set for the TRIES molecule, therefore, is the most reliable so far for plasma discharges and for materials processing using the TRIES molecule. Moreover, the electron transport coefficients for the TRIES-Ar and the $TRIES-O_2$ mixtures were also calculated and analyzed over a wide range of E/N for the first time.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1734-1737
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• 2015

Insulating characteristics of Cl₂-He mixture gases in gas discharges were analysed to evaluate ability of these gases for using in medium voltage and many industries. These are electron transport coefficients, which are the electron drift velocity, density-normalized longitudinal diffusion coefficient, and density-normalized effective ionization coefficient, in Cl₂-He mixtures. A two-term approximation of the Boltzmann equation was used to calculate the electron transport coefficients for the first time over a wide range of E/N (ratio of the electric field E to the neutral number density N). The limiting field strength values of E/N, (E/N)_lim, for these binary gas mixtures were also derived and compared with those of the pure SF₆ gas.

• Journal of the Korean Vacuum Society
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• v.8 no.3B
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• pp.353-360
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• 1999

The global balance model is applied to investigate the transient behavior of the electron density and temperature in helicon plasmas. The power absorption calculated from the solutions of the Maxwell equations is used in solving the power balance equation. A balance model for the neutral gas is also considered to fins its density self-consistently. It is turned out that the numerical results reasonably explain consequences of the ion pumping effect including the occurrence of two distinct modes of pulsed helicon discharge which have been observed experimentally. The behavior of the discharge parameters are fond to be primarily dependent on the power absorption and the gas flow rate, but the pressure controls the electron density and temperature of the final steady state as well as the transient state even with the same flow rate. Finally, it is shown that the electron density virtually the linear relationship between the density and the magnetic field is retained for a higher pressure when the effect of the ion pumping is negligible.