• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.4
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• pp.467-474
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• 2004

A large-eddy simulation is performed for turbulent flow in a concentric annulus with the inner wall rotation at Re$\sub$Dh/=8900 for three rotation rates N=0.2145, 0.429 and 0.858. Main emphasis is placed on the inner wall rotation effect on near-wall turbulent structures. Near-wall turbulent structures close to the inner wall are scrutinized by computing the lower-order statistics. The anisotropy invariant map for the Reynolds stress tensor and the invariant function are illustrated to reveal the altered anisotropy in turbulent structure. Probability density functions of the splat/anti-splat process are explored to develop a sufficiently complete picture of the contributions of the flow events to turbulent production. The present numerical results show that the altered turbulent structures may be attributed to the centrifugal instability, which leads to the augmentation of sweep and ejection events.

• Transactions of Materials Processing
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• v.11 no.4
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• pp.332-340
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• 2002

The light guide plate of the TFT-LCD reflects the light originated from the light source, and guides the light to the front side of LCD so that we can see images vividly. This paper is concerned with tile injection molding of the light guide plate for the reflective typed LCD related to IMT-2000. The finite element analysis has been carried out based on the pine stress theory to predict both the thermal stresses of the products in the post-filling stage and the in-plane deformation behavior of the products after ejection process. Based on the simulation results, the mold for the light guide plate of a 2inch sized LCD has been designed.

• Journal of Chest Surgery
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• v.15 no.2
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• pp.238-242
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• 1982

The incidence of annuloaortic ectasia has known rare, and approximately 5-10% of aortic regurgitation. The patient was 44 years old male who complained exertional dyspnea and left anterior chest pain. He had done Lt. side 2 stage thoracoplasty for pulmonary tuberculosis about 20 years ago at Dept.of Chest surgery of National Medical Center. At that time, there was no abnormal findings in cardiovascular system. The preoperative aortic cineangiogram showed pear shaped dilatation [7.3 cm x 6.8 cm] of aortic mot with aortic valve regurgitation but left ventricular ejection function was fair. Preop. ventilatory function test showed mixed type pulmonary insufficiency. Recently, we corrected surgically, by AVR with Carpentier-Edwards Bioprosthesis [29mm] & supracoronary Woven Dacron graft [29mm x 5cm] replacement, with good clinical result for follow up 6 months.

• 대한핵의학회:학술대회논문집
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• 1997.05a
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• pp.173-173
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• 1997

• 한국전산유체공학회:학술대회논문집
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• 2005.10a
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• pp.239-243
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• 2005

Fully three-dimensional Large Eddy Simulation calculations of the flow past 2D cavity are conducted to study the purging of neutrally buoyant or dense miscible contaminants introduced instantaneously inside the cavity. The length to depth ratio(L/D) is 2 and Reynolds number based on the depth is 3,360. Fully developed turbulent inflow are fed at the inlet from precursor simulation of channel flow. Mean flow pattern and unsteady features are investigated based on the experimental data of Pereira and Sousa. From the study of mass exchange processes, it is found that the mechanism of removal of the contaminant is very different between the non-buoyant and buoyant cases. In the buoyant case, internal wave motion which interacts with a strong cavity vortex is dominant in the ejection mechanism of the contaminants.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2000.05a
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• pp.165-170
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• 2000

A fundamental experimental study for a substitute proposal to super-speed craft propulsion system called underwater ram-jet propulsion by high pressure air ejection as driving force was investigated. for basic study of effect of ram-jet propulsion performances ismple underwater ram-jet flow field was established and PIV(Particle Image Velocimetry) method was adopted to analyse the jet-induced flow appearing at ram intake mixing chamber and nozzle. Some flow dynamics relating to the high-speed ejector effect were discussed for the basic understanding for the ram-jet propulsion principle.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.11
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• pp.101-107
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• 2007

Jettability analysis using one-dimensional(1D) lumped parameter model has been investigated to design the industrial inkjet head with proper drop velocity and drop volume. By simplifying the inkjet head system into an equivalent electrical circuit, lumped model has been developed. Performance of the lumped model is verified by the comparison between measured results of droplet velocity and ejection volume and predicted value. Also, the jetting performance of an inkjet head is characterized by varying the design parameter and driving condition. As a result, simulation results shows good agreement with the experimentally measured value. The developed lumped model enables to easily understand the effect of dimension change and predict the jetting performance.

• Journal of Pharmaceutical Investigation
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• v.38 no.5
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• pp.303-311
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• 2008

Highly hydrophobic lubricants including magnesium stearate may hinder water penetration into the tablet core resulting in delayed disintegration of fast disintegrating tablets. Alternative lubricants with equivalent lubricating properties may need to be incorporated into the tablet formulations. Sodium stearyl fumarate, glyceryl behenate and polyethylene glycol were evaluated regarding the tablet ejection energy, mechanical strength and disintegration time using Texture analyzer (TA). Resulting tablets were also compared with different particle sizes of granules and various compression forces. Among the tested lubricants, sodium stearyl fumarate was less sensitive to mixing time and also showed better or competitive tablet properties. During the experiments, TA was found to be very useful tool to investigate the tablet properties.

• Journal of Biomedical Engineering Research
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• v.36 no.5
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• pp.198-203
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• 2015

The purpose of the study is to examine the effects of pacemaker location on cardiac pumping efficacy theoretically. We used a three-dimensional finite element cardiac electromechanical model of canine ventricles with models of the circulatory system. Electrical activation time for normal sinus rhythm and artificial pacing in apex, left ventricular free wall, and right ventricular free wall were obtained from electrophysiological model. We applied the electrical activation time maps to the mechanical contraction model and obtained cardiac mechanical responses such as myocardial contractile ATP consumption, stroke work, stroke volume, ejection fraction, and etc. Among three artificial pacing methods, left ventricle pacing showed best performance in ventricular pumping efficacy.

• Journal of the Korean Society of Industry Convergence
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• v.2 no.1
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• pp.121-130
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• 1999

It is necessary to measure pressure, temperature, chemical equilibrium and the shape of flame in order to understand the combustion process in a combustion chamber. In particular, the flame formulation and combustion process of divided combustion chamber are different from those of a single chamber, And the variable diameter of a jet hole can effect not only physical properties like ejection velocity, temperature and time of combustion but also a chemical property like the reaction mechanism. Accordingly temperature is one of the most important factors which influence the combustion mechanism. This paper observed shape of flame by using the schlieren photographs and measured the pressure in a combustion chamber and the reaching time of the flame by ion probe By doing these, we investigation the formulation of the flame and the process of propagation. These measurement methods can be advanced in understanding the combustion process and process and propagation of flame.