• Journal of the Korean Crystal Growth and Crystal Technology
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• v.23 no.1
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• pp.20-26
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• 2013

Special attention in the role of convection in vapor crystal growth has been paid since some single crystals under microgravity environments less than 1 $g_0$ exhibits a diffusive-convection mode and much uniformity in front of the crystal regions than a normal gravity acceleration of 1 $g_0$. The total molar fluxes show asymmetrical patterns in interfacial distribution, which indicates the occurrence of either one single or more than one convective cell. As the gravitational level decreases form 1 $g_0$ down to $1.0{\times}10^{-4}\;g_0$, the intensity of convection, indicative of the maximum molar fluxes, is reduced significantly for ${\Delta}T=30K$ and 90 K. The total molar fluxes decay first order exponentially with the partial pressure of component B, PB (Torr) for 20 Torr ${\leq}PB{\leq}$ 300 Torr, and two gravity accelerations of $g_y=1\;g_0$ and 0.1 $g_0$.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.3
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• pp.475-481
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• 2004

Recently it is strongly required on lower fuel consumption. lower exhaust emission, higher engine performance. and social demands in a spark ignition gasoline engine. In this study. the experimental engine used at test. it has been modified the lean burn gasoline engine. and used the programmable engine management system, and connected the controller circuit which is designed for the engine control. At the parametric study of the engine experiment, it has been controlled with fuel injection, ignition timing. swirl mode, equivalence ratio engine dynamometer load and speed as the important factors governing the engine performance adaptively. It has been found the combustion characteristics to overcome the hysteresis phenomena between normal and lean air-fuel mixing ranges. by mean of the look-up table set up the mapping values. at the optimum conditions during the engine operation. As the result, it is found that the strength of the swirl flow with the variation of engine speed and load is effective on combustion characteristics to reduce the bandwidth of the hysteresis regions. The results show that mass fraction burned and heat release rate pattern with crank angle are reduced much rather, and brake specific fuel consumption is also reduced simultaneously.

• JSTS:Journal of Semiconductor Technology and Science
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• v.7 no.2
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• pp.120-131
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• 2007

A comprehensive short channel analytical model has been proposed for High Electron Mobility Transistor (HEMT) to obtain higher cut-off frequency maintaining the reliability of the device. The model has been proposed to consider generalized doping variation in the directions perpendicular to and along the channel. The effect of field plates and different gate-insulator geometry (T-gate, etc) have been considered by dividing the area between gate and the high band gap semiconductor into different regions along the channel having different insulator and metal combinations of different thicknesses and work function with the possibility that metal is in direct contact with the high band gap semiconductor. The variation obtained by gate-insulator geometry and field plates in the field and channel potential can be produced by varying doping concentration, metal work-function and gate-stack structures along the channel. The results so obtained for normal device structure have been compared with previous proposed model and numerical method (finite difference method) to prove the validity of the model.

• Journal of Veterinary Clinics
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• v.32 no.1
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• pp.112-114
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• 2015

A 1-month-old female Korean native calf was referred to the Veterinary Medical Teaching Hospital, Kyungpook National University. The chief complaint was a supernumerary limb on the dorsal thoracic region. The ectopic limb was smaller than normal limbs and it was partially attached on the ribs. Surgical excision was performed to remove the supernumerary ectopic limb and notomelia was successfully corrected. Supernumerary ectopic limb is defined as the presence of accessory limb or limbs attached to various body regions. This study reports macroscopic and radiographic features of notomelia in a female Korean native calf.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.1
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• pp.38.1-38.1
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• 2017

We report the results of three-dimensional radiation hydrodynamic simulations of star cluster formation in turbulent molecular clouds, with primary attention to how stellar radiation feedback controls the lifetime and net star formation efficiency (SFE) of their natal clouds. We examine the combined effects of photoionization and radiation pressure for a wide range of cloud masses (10^4 - 10^6 Msun) and radii (2 - 80 pc). In all simulations, stars form in densest regions of filaments until feedback becomes strong enough to clear the remaining gas out of the system. We find that the SFE is primarily a function of the initial cloud surface density, Sigma, (SFE increasing from ~7% to ~50% as Sigma increases from ~30 Msun/pc^2 to ~10^3 Msun/pc^2), with weak dependence on the initial cloud mass. Control runs with the same initial conditions but without either radiation pressure or photoionization show that photoionization is the dominant feedback mechanism for clouds typical in normal disk galaxies, while they are equally important for more dense, compact clouds. For low-Sigma clouds, more than 80% of the initial cloud mass is lost by photoevaporation flows off the surface of dense clumps. The cloud becomes unbound within ~0.5-2.5 initial free-fall times after the first star-formation event, implying that cloud dispersal is rapid once massive star formation takes place. We briefly discuss implications and limitations of our work in relation to observations.

• Journal of Ocean Engineering and Technology
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• v.27 no.4
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• pp.83-89
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• 2013

A numerical scheme based on a mode superposition method is presented for the dynamic response analysis of a top-tensioned riser (TTR) under sheared current loads. The natural frequencies and mode shapes of the TTR have been calculated analytically for a beam with a slowly varying tension and pinned-pinned boundary conditions at the top and bottom ends. The lift coefficients and corresponding amplitudes used to estimate the vortex-induced modal force and damping for each mode were predicted via iterative calculations based on the input and output power balancing concept. Here, the power-in regions were controlled by the normal distribution function, for which the center was coincident with the lock -in location by local vortex-shedding, and the range was defined by the constant standard deviation for the reduced velocity by the local current speed. Finally, dynamic responses such as root-mean-squared displacement and stress were calculated using the mode superposition technique. In order to verify the presented scheme, a numerical calculation was performed for a TTR under an arbitrary linearly sheared current and linearly varying tension. A comparison with the results of the existing software showed that the presented scheme could give reliable and feasible solutions. Case studies were performed to investigate the effects of various current loads and tensions.

• Korean Journal of Adult Nursing
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• v.14 no.4
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• pp.532-542
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• 2002

Purpose: This study were to investigate BMD of middle-aged women and to examine the relationships between BMD and Physical, Obstetric characteristics Method: The data was collected from 119 healthy women who were 40-60 years old. they were examined for BMD at 4 regions(forearm, lumbar, femur, whole body), %fat by DEXA and investigated physical, obstetric characteristics using scale, questionnaire from January to March, 2001. Result: 1) According to bone diagnostic results by WHO classification, 95.8% of forearm and whole body BMD were normal but 21.8-48.7% of lumbar and femur BMD(neck, trochanter, ward's triangle) were diagnosed osteoporosis or osteopnea. 2) The bones were significantly positive correlations of each other (r=.19-.69, p=.04-.00) and there were significant correlations between BMD and physical, obstetric characteristics such as age (r=-.22, p=.02), weight(r=.36~.48, p=.00), height(r=.22, p=.02), %fat(r=.19, p=.04) and age of first delivery(r=-.28, p=.00). Conclusion: Based on this study, healthy middle-aged women were also exposed to risk of osteoporosis related to aging, change of physical conditions or hormonal release. Further research to develop nursing interventions for the purpose of preventing osteoporosis by modifying risk factors is suggested.

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.1
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• pp.139-144
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• 2001

In order to analyze of the color perception Farnsworth Test Panel D-15 in the CIELab color space coordinates, it was measured by the reflectance spectrum of the 380~780nm wavelength regions. The Test Panel D-15 was situated in the near origin point of higher the saturation in CIELab coordinates (a, b). Normal person perceived to the similar color for the color of small color difference, and color deficiency person depended on the confusing color line and the neutral point unconcerned with the color difference. In case of Ptotanopia, Deutrnopia, r-g defect, y-b defect with the color deficiency, the neutral points position (a,b) were each (2.12,1.02), (4.25,2.05), (2.51,0.25), (1.20,-1.10).

• Journal of the Korean Society for Marine Environment & Energy
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• v.5 no.3
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• pp.10-15
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• 2002

The assessment of PIV to measure the mean velocity and turbulence was carried out over a train of fixed two-dimensional dunes. The agreement between the PIV and LDV is good enough even in regions of flow reversals and high shear. Though limited in the wall normal direction field-of-view, PIV provides instantaneous flow fields, which reveal the complex nature of flow over dunes, as well as more sophisticated analyses such as two-point space correlation and quadrant analysis with a reasonable accuracy The present study is expected to be directly applied to more complex flow such as sediment transport.

• Journal of radiological science and technology
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• v.27 no.3
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• pp.19-24
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• 2004

MRI imaging is one of the imaging techniques showing anatomical structures of human body for medical diagnosis, and has been researched in order to provide better quality of anatomical information. In this study, we propose a very useful method to extract an interest areas and how to diagnose necrolysis of femoral neck disease automatically. Regions of femoral neck is set using anatomical features and Hough transform and advantages of both region extension and histogram-based region segmentation method are combined for better region segmentation. As a result of the proposed method, good imaging quality was obtained for femoral neck with both normal and severe necrosis as well as for femoral neck in early stage of necrolysis.