• Journal of Mechanical Science and Technology
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• v.17 no.9
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• pp.1316-1323
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• 2003

This paper presents a structural analysis on the rigid and deformed motion of the leaflet induced by the blood flow required in the design of a bileaflet mechanical heart valve (MHV) prosthesis. In the study on the design and the mechanical characteristics of a bileaflet mechanical heart valve, the fluid mechanics analysis on the blood flow passing through leaflets, the kinetodynamics analysis on the rigid body motion of the leaflet induced by the pulsatile blood flow, and the structural mechanics analysis on the deformed motion of the leaflet are required sequentially and simultaneously. Fluid forces computed in the previous hemodynamics analysis on the blood flow are used in the kinetodynamics analysis on the rigid body motion of the leaflet. Thereafter, the structural mechanics analysis on the deformed motion of the leaflet follows to predict the structural strength variation of the leaflet as the leaflet thickness changes. Analysis results show that structural deformations and stresses increase as the fluid pressure increases and the leaflet thickness decreases. Analysis results also show that the leaflet becomes structurally weaker and weaker as the leaflet thickness becomes smaller than 0.6 mm.

• Korean Journal of Metals and Materials
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• v.46 no.2
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• pp.105-110
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• 2008

Process of the hydroxyapatite (HA) formation on bioactive titanium metal prepared by NaOH treatment in a modified-simulated body fluid (mSBF) containing bovine serum albumin (BSA) was investigated by high resolution transmission electron microscope attached with energy dispersive X-ray spectrometer (EDX). The amorphous titanate, which was formed on titanium surface by NaOH treatment, combined with the calcium ions in the liquid to form an amorphous calcium titanite. With increasing of soaking time in the liquid, an amorphous calcium titanite combined with the phosphate ions to form an amorphous calcium phosphate with low Ca/P atomic ratio, and it grows as aggregates of plate (or needle)-like substance on titanium surface. The crystalline apatite layers, which are needle-shaped with the c axis parallel to the long axis, are formed in an amorphous calcium phosphate with further increase in soaking time. The formation of needle-shaped apatite layers can be explained by electrostatic effects and difference of concentration between calcium, phosphate, and albumin ions.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.191-195
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• 2001

The applications of magnetic fluid can be normally made by 1) using changes of a property of matter caused by applied magnetic field; 2) preserving magnetic fluid at a certain position or in a magnetic fluid keeping the body in a floating condition; 3) controlling the flow of magnetic fluid by means of magnetic field. However, these are usually made by using their methods together. In this study, the natural convection flow of a magnetic fluid in annular pipes is experimentally analyzed. High temperature is kept constantly inside of a circular pipe of experimental model, on the other hand, low temperature is kept constantly outside of it. In experiments, several cases are carried out in order to clarify the fluence of direction and intensity of magnetic fields on the natural convection of magnetic fluid. Therefore magnetic fields are applied in various intensity and up and down directions by permanent magnets.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.297-300
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• 2002

In this study, the deformation of the free surface motion of a magnetic fluid for the change in electromagnetic force is discussed and carried out theoretically and experimentally on the basis of Rosensweig Ferrohydrodynamic Bernoulli Equation. While applied magnetic fields are induced by 4$\times$4 electromagnet located under the magnetic fluid, the surface of the magnetic fluid is formed the balance of surface force, gravity, pressure difference, magnetic normal pressure and magnetic body farce. In case, magnetic fluid in characteristics of fluid adjusted to the opposite direction of the gravity direction. thus, the device of a magnetic fluid proposed the surface actuator. The device of surface deformation as well comparison between numerical simulation and experiments as will be presented.

• The Journal of Korean Obstetrics and Gynecology
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• v.28 no.2
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• pp.91-108
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• 2015

Objectives : The aim of this study was to investigate the effect of Omibaekchul-san on postpartum edema in women hospitalized at korean medical postpartum care center in comparison with Saenghwa-tang. Methods : The body composition data was collected from 102 women, who took postpartum care in postpartum care center attached to Won-kwang University Jeonju Korean Medical Hospital, from March 2012 to July 2013. The data was analyzed by Body Composition Analyzer (Inbody 720). Specifically the data was composed of the Extra Cellular Fluid/Total Body Fluid (ECF/TBF), Total Body Water (TBW), Intra Cellular Water (ICW), Extra Cellular Water (ECW), Body Weight, Body Mass Index (BMI), Waist Hip Ratio (WHR), and the ECF/TBF of each body parts such as the upperlimb, lowerlimb and trunk. The body composition was measured twice during 2~8.5 days from childbirth and once again after 7~13.5 days from childbirth by Body Composition Analyzer. Results : The Omibaekchul-san -treated group showed a significant decrease of ECF/TBF, ECW, TBF, Body weight, BMI, ECF/TBF of each body parts and increase of WHR in comparison with the data of the Saenghwa-tang-treated group. In two groups, only the change of ICW was unsignificant. Conclusions : Statistically this study suggests that the Omibaekchul-san will help the quality of life of women who are in postpartum edema.

• Journal of Korean Physical Therapy Science
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• v.10 no.2
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• pp.208-215
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• 2003

This study measured body composition and muscular strength, to examine their relationship, using the Bioelectrical Impedance (IB) method and biodex system3, respectively, in 44 healthy male(20) and female(24) university students. 1. Muscular strength of the upper extremities correlated significantly with fat-free mass(FFM) with $r=.604{\sim}.630$ and intracellular fluid(ICF) with $r=.672{\sim}.668$ in males and FFM with $r=.416{\sim}.552$, ICF with $r=.432{\sim}.564$ and extracellular fluid(ECF) with $r=.429{\sim}.463$ in females. 2. Muscular strength of the lower extremities correlated significantly with FFM with $r=.522{\sim}.785$, ICF with $r=.501{\sim}.739$ and ECF with $r=.498{\sim}.796$ in males and FFM with $r=.642{\sim}.660$, ICF with $r=.627{\sim}.671$ and ECF with $r=.572{\sim}.623$ in females. 3. Muscular strength of the trunk correlated with FFM with $r=.595$, ICF with $r=.627$, ECF with $r=.448$ in males, but did not correlate significantly with body composition in females. These results suggest that total body water(TBW) and ICF may be factors directly associated with muscular strength as well as physical fitness.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.10
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• pp.984-991
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• 2009

In this study, transonic aeroelastic response analyses have been conducted for the DLR-F4(wing-body) aircraft configuration considering shockwave and flow separation effects. The developed fluid-structure coupled analysis system is applied for aeroelastic computations combining computational structural dynamics(CSD), finite element method(FEM) and computational fluid dynamics(CFD) in the time domain. It can give very accurate and useful engineering data on the structural dynamic design of advanced flight vehicles. For the nonlinear unsteady aerodynamics in high transonic flow region, Navier-Stokes equations using the structured grid system have been applied to wing-body configurations. In transonic flight region, the characteristics of static and dynamic aeroelastic responses have been investigated for a typical wing-body configuration model. Also, it is typically shown that the current computation approach can yield realistic and practical results for aircraft design and test engineers.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.5
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• pp.784-789
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• 2010

Syndrome of asthenia of spleen gi usually caused by improper diet, overstrain, emotional upsets, followed by syndrome of sinking of splenic gi. There are several pathologic categories of splenic gi deficiency syndrome. These include failure to nourish the body, failure to astringe liquid substances, failure of splenic gi to rise, gi stagnation in which gi can't disperse normally, failure of transportation. In the splenic gi deficient situation, body fluid is usually stagnated because the rest of the water absorbed from the food is transported to every part of the body by the action of splenic gi. In addition, there is abnormal sinking of clear gi, followed by fever due to gi deficiency. Bojungikgi-tang is composed of restoratives which are invigorating splenic gi and herbs which uplift splenic gi. It is mainly applicable to splenic gi deficiency syndrome accompanied by gi stagnation and fluid accumulation.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.937-942
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• 2000

The characteristics of spray combustion and dropsize of spray through twin-fluid atomizer was experimentally investigated. The distribution of flame temperature have an effect on the generation of NOx. To investigate there effects, flame temperature with different spray shape was observed. The spray shape was varied by various bluff-bodys. Mean temperature were measured by thermocouple respectively, and NOx concentration was measure by NOx analyser. Distribution of droplet sizes were measured by PMAS. The result showed that the flame with wide distribution has lower temperature and lower NOx emission compared with narrow.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.19 no.4
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• pp.459-479
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• 2015

Two-dimensional steady laminar natural convection around a heat conducting and generating solid body inside a square enclosure with different thermal boundaries is performed. The mathematical model is governed by the coupled equation of mass, momentum and energy. These equations are discretized by finite volume method with power-law scheme and solved numerically by SIMPLE algorithm with under-relaxation technique. Effect of Rayleigh number, temperature difference ratio of solid-fluid, aspect ratio of solid-enclosure and the thermal conductivity ratio of solid-fluid are investigated numerically for Pr = 0.7. The flow and heat transfer aspects are demonstrated in the form of streamlines and isotherms respectively.