• Journal of Advanced Marine Engineering and Technology
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• v.24 no.1
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• pp.75-81
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• 2000

To provide the appropriate direction for development of transient control in a gasoline engine, transient performance analysis and evalution under four accelerating types based on typical driver's acceleration type were implemented by experimental study. In order to evaluate the characteristics of transient performance quanititatively, the concept and method by transient response specifications were introduced. Several performance parameters in terms of engine speed(RPM), manifold absolute pressure(MAP), fuel injection duration($\DeltatI_{nj}$) and air excess ratio($\lambda$) were emasured simultaneously during the four types of the throttle valve opening with the step motor controlled by PC. The result showed that transient response specifications in terms of delay time, rising time and settling time characterized the transient performance for four acceleration types quantitatively. Intensified acceleration type was most economical and linear acceleration type revealed the best emission performance.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05b
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• pp.683-690
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• 1996

The MIDLOOP code has been developed for the evaluation of RES pressurization transients initiated from a loss-of-Residual Heat Removal System (RHRS) during mid-loop operation after reactor shutdown. It provides a fast running and realistic tool for studying parametrically the response of important plant parameters such as pressure, temperature, and level to various plant combinations of the primary side vent, makeup, and leakage procedures and the steam generator (SG) conditions. The code consists of ten nodes representing the primary and secondary sides of a nuclear power plant and can analyze the effect of air on the primary system pressurization and primary to secondary heat transfer. The analysis results of the MIDLOOP code are in good agreement with the ROSA-IV/LSTF experiment without opening in the RCS.

• Journal of Oral Medicine and Pain
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• v.21 no.1
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• pp.25-36
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• 1996

To investigate the effect of low level laser therapy, the author selected 37 dental students with tender points in both masseters and trapeziuses, also measured maximum comportable opening(MCO), Numerical analog scale(NAS) and pressure pain threshold (PPT). 20 subjects were assigned randomly and were treated with GaAlAs diode laser after ultrasound. The other 17 subjects were treated with ultrasound and laser without irradiation. All the subjects were treated after 2 and 4 day respectively and were examined again after 6 days. And the obtained results were as follows : 1. The MCO of irradiated group increased more significantly after treatment than non-irradiated group. 2. The NAS of irradiated group decreased more significantly after treatment than non-irradiated group. 3. The PPT or irradiated group increased more significantly after treatment than non-irradiated group.

• 한국전산유체공학회:학술대회논문집
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• 2005.10a
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• pp.281-285
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• 2005

Viscous solutions of supersonic jet impinging on a flat wall in a confined plenum are simulated using three-dimensional Navier-Stokes solver. A confined plenum was designed for simulating the missile launch and analyzing the behavior of the exhaust plume, which were accompanied by complex flow interactions with shock and boundary layer. Concerns of this paper are to show accurate simulation of internal flow in confined plenum and to demonstrate the jet flow structure when the jet interacts with a small opening on the side. Objectives of this numerical simulation are to understand the effect of changing the plume exit area of the plenum. Pressure and temperature rise at certain position in the plenum are traced and compared with test data.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.175-178
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• 2007

Valves has been used widely in various industries. There are many purposes for valve usage in a piping system. One of them is to control the flow rate. For a design of ball valves, it is important to know the characteristics of flows inside a ball valve. In this study, the computation fluid dynamics were conducted to observe flow velocity, flow coefficient and pressure distribution using CFX 10 according to the valve angles and uniform incoming velocity.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.2_2
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• pp.199-207
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• 2020

These days, many different types of valves are developed in the industrial area according to their use purpose. Multiple kinds of valves are installed to control a flow and pressure of the pipe conveying fluid. Valves serve as critical roles in land plants such as power plants. The performance of equipment varies depending on valve characteristics. In this study, the internal flow analysis on Cone-type valve is conducted to analyze flow field and secure a value of the flow coefficient Cv. According to the internal flow analysis, when the flow distribution of the middle cross-section of valve was open 100%, flow field was relatively and smoothly taken out. If it was open 50%, flow recirculation region increased and a little complex flow field occurred. Unlike ball valve or butterfly valve, this valve had flow recirculation in its outlet depending on a valve opening amount. Therefore, it was found that there was no flow recirculation in the outlet of Cone-type valve.

• Journal of Chest Surgery
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• v.13 no.2
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• pp.130-133
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• 1980

Since the first report of an operation for prolapsed intervertebral disk by Mixter and Barr[1934], many thousands of operations have been successfully performed without incident. Linton and White in 1945 reported the vascular complication, but perforation of large vessels is rare complication of operation for prolapsed disk. A medical student, aged 22 years, was performed to a disk operation [L4-5, Rt. on May 1977.] From postoperative 10th day, palpitation, generalized edema and substernal pain were noted, and 2 months later, wide pulse pressure [70-80 mmHg], continuous bruit and thrill on the Rt. low abdomen were followed. Aortography revealed arteriovenous fistula between just proximal to abdominal aortic bifurcation and inferior vena cava. So, fistulectomy [Resection of proximal 2 cm of C.I.A., Rt, including fistula opening and end to end anastomosis] was performed on July, 77. During follow up study, remained fistula between Rt. internal lilac artery and lilac vein was found 2 months later. Re-operation [Double ligation of the Rt. internal lilac artery] was don on January 1978. Postop. results were excellent, except impossible to ejaculation.

• Journal of Chest Surgery
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• v.11 no.2
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• pp.194-198
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• 1978

Congenital aortic stenosis, a relatively uncommon congenital heart disease, may cause heart failure and may be fatal. In recent years, increased clinical awareness and improved diagnostic and operative technique has made accurate diagnosis and successful treatment possible. Recently we experienced 2 cases of congenital aortic stenosis, and which was corrected surgically. The first case was 9 years old boy, and second case was 16 years male. Preoperative diagnosis was entertained by angiography and cardiac catheterization in both cases. In each case, aortic valve opening was widened by incision along the fused commissure between the combined left and right coronary cusp on one side, and the noncoronary cusp on the other side. Post-op. pressure gradient between the aorta and left ventricle markedly reduced, in the first case, 50mmHg, and in the 2nd case, 55mmHg.Both patients discharged with good results 2 weeks after open heart surgery.

• The KSFM Journal of Fluid Machinery
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• v.11 no.4
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• pp.14-21
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• 2008

The prediction for gaseous leak flows through a narrow crack is important for a leak-before-break (LBB) analysis. Therefore, the methodology to obtain the flow characteristics of gaseous leak flow in a narrow crack for the wide range by using the product of friction factor and Reynolds number correlations (fRe) for a micro-channel is developed and presented. The correlation applied here was proposed by the previous study. The fourth-order Runge-Kutta method was employed to integrate the nonlinear ordinary differential equation for the pressure and the regular-Falsi method was also employed to find the inlet Mach number. A narrow crack whose opening displacement ranges from 10 to $100{\mu}m$ with a crack length in the range from 2 to 200mm was chosen for sample prediction. The present results are compared with both numerical simulation results and available experimental measurements. The results are in excellent agreement with them. The leak flow rate can be approximately predicted by using proposed methodology.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.1
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• pp.110-118
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• 2008

It is essential for the valid design of a marine flow-control valve to exactly know its flow characteristics. The present study has numerically investigated the flow characteristics inside a marine throttle-type globe valve using a kind of commercial CFD code, CFX10.0, with an adoption of the SST (Shear-Stress Transport) turbulence model. To validate the numerical approach, the flow coefficients are compared with the experimental ones. Results show that the globe valve is effective in the control of flow rate according to the opening ratio in case of the forward-direction flow, whereas it is effective in the flow shutoff in case of the reverse-direction flow. Around the inlet of the valve, a recirculation region is formed due to the blunt body shape, the turbulence intensity becomes strengthened and then an abrupt pressure loss occurs.