• Journal of Chest Surgery
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• v.21 no.4
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• pp.700-705
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• 1988

A case of congenital tricuspid stenosis in 24 year old male patient is presented. The lesion was successfully corrected with prosthetic valve replacement and closure of atrial and ventricular septal defects. Especially, this is the first reported case of successful large prosthetic valve replacement to a small annulus in tricuspid valve.

• Journal of Clinical Otolaryngology Head and Neck Surgery
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• v.29 no.2
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• pp.269-275
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• 2018

Nasal valve compromise (NVC) is a distinct cause of symptomatic nasal obstruction, yet there are several ambiguities surrounding the diagnosis and management of this disease. Understanding of nasal valve anatomy with critical assessment of the site of obstruction is essential to effective nasal valve management. Technique selection should be individualized to the type of valve dysfunction. This case report presents a 56 year old man with nasal valve dysfunction due to narrow middle vault, concave lower lateral cartilage and swollen septal body which was diagnosed by various techniques including navigation system and treated by spreader graft, alar batten graft and reduction of septal body.

• Journal of Power System Engineering
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• v.11 no.3
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• pp.35-40
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• 2007

Leak would happen because of the damage of high temperature and high-pressure valve in nuclear power plant. condition based prevention maintenance is essential by using the suitable method based on local condition. Energy loss prevention can prevent from an accurate test, Local actually and ability. The methods of test for high energy fluid leak at present are analysis of ${\Delta}T$, AE(Acoustic Emission) analysis, and thermal image. The result for test of secondary system in nuclear power plant Unit reveals that the AE occurred clearly in leakage situation, but thermal image didn't occur. It is identified that leak is occurred when the orifice located front and back of valve operates. It shows that making a impatient judgment by using the single method if it is leakage is containing uncertainty. So we think that using the Multi-Measuring method is more sound judgment than single-measuring method.

• Journal of Hydrogen and New Energy
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• v.26 no.4
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• pp.386-392
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• 2015

Flow characteristics inside a 10 inch ball valve have been analyzed using three-dimensional numerical analysis and experiments. Continuity and three-dimensional Reynolds-averaged Navier-Stokes equations have been used as governing equations for the numerical analysis. The numerical model has been constructed through the grid dependency test and validation with the results of experiments to ensure reliability and numerical effectiveness. The shear stress transport (SST) model has been used as the turbulence closure. The experimental test-rig has been constructed to measure pressure, temperature and flow rate along the pipeline. Some valve opening angles have been tested to evaluate the flow characteristics inside the ball valve and pipeline. The results show that the rapid pressure variations is observed while the valve opening angle decreases, which caused by flow separation at the downstream of the ball valve.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.3
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• pp.109-115
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• 2019

The purpose of this study was to analyze and test the flow rate of a 1-inch ball valve used in a thermal power plant. To identify the flow-rate characteristics, numerical analysis was conducted and an experimental apparatus of the valve flow rate coefficient was used to compare the flow coefficient Cv values. To determine the internal pressure distribution, the sites of opening ball valves and flow fields were investigated. In particular, a smaller the valve opening resulted in a more complicated the flow field of the ball. The valve flow characteristic test showed that the Cv value and flow rate increased with increasing valve-opening rate and the secondary function was performed. The pressure drop increased as the valve opening rate decreased. In addition, the experimental results for the flow analysis are similar to the numerical analysis results.

• Korean Circulation Journal
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• v.53 no.11
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• pp.775-786
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• 2023

Background and Objectives: Tricuspid valve (TV) repair techniques other than annuloplasty remain challenging and frequently end in tricuspid valve replacement (TVR) in complicated cases. However, the results of TVR are suboptimal compared with TV repair. This study aimed to evaluate the clinical effectiveness of TV edge-to-edge repair (E2E) compared to TVR for severe tricuspid regurgitation (TR). Methods: We retrospectively reviewed 230 patients with severe TR who underwent E2E (n=139) or TVR (n=91) from 2001 to 2020. Clinical and echocardiographic results were analyzed using inverse probability of treatment weighting analysis and propensity score matching. Results: The two groups showed no significant differences in early mortality and morbidities. During the mean follow-up of 106.2±68.8 months, late severe TR and TV reoperation rates were not significantly different between groups. E2E group, however, showed better outcomes in overall survival (p=0.023), freedom from significant tricuspid stenosis (TS) (trans-tricuspid pressure gradient ≥5 mmHg, p=0.021), and freedom from TV-related events (p<0.001). Matched analysis showed consistent results. Conclusions: E2E for severe TR presented more favorable clinical outcomes than TVR. Our study supports that E2E might be a valuable option in severe TR surgery, avoiding TVR.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3074-3079
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• 2007

The conventional control valves have been used at the locations occurring high differential pressure and high temperature which causes cavitation, flashing, severe vibration due to abrupt flow change, and sudden pressure drop. Previous studies concerning control valves focused to prevent damage of valve trim due to the internal leak and low flow rate. The newly designed helical trim of control valve has been installed at the location of high pressure change and high temperature in a power plant, and operated for evaluation. It is confirmed that the new control valve developed in this study generates flow characteristics in comparison with previous helical trim of control valves.

• Journal of ILASS-Korea
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• v.23 no.1
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• pp.1-8
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• 2018

In this study, the effects of variation in cam phasing and valve lift of exhaust valves by using Cam-in-Cam system on combustion and emission characteristics for diesel engine were investigated under GT-POWER simulation environment. This paper showed analytic result of combustion characteristics and diesel exhaust valve's control with GT-Power 1-D detail model. As a result, it was found that volumetric efficiency and IMEP were decreased as the exhaust valve opening and closing timing is advanced due to its internal EGR effects. Also, it was found that NOx emission were decreased as EVC timing was retarded. These show that the retarding the exhaust valve closing and opening while keeping the duration at constant can be effective for controlling AFR and mixing rate in diffusion combustion of diesel engine.

• Journal of Yeungnam Medical Science
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• v.35 no.1
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• pp.17-26
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• 2018

Transcatheter aortic valve implantation (TAVI) has evolved from a challenging intervention to a standardized, simple, and streamlined procedure with over 350,000 procedures performed in over 70 countries. It is now a novel alternative to surgical aortic valve replacement in patients with intermediate surgical risk and its indications have been expanded to cohorts with bicuspid aortic valves, low surgical risk, and younger age and fewer comorbidities. Attention should be paid to further reducing remaining complications, such as paravalvular aortic regurgitation, conduction abnormalities, cardiac tamponade, and stroke. The aim of this review is to provide an overview on the rapidly changing field of TAVI treatment and to explore past achievements, current issues, and future perspectives of this treatment modality.

• Journal of Chest Surgery
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• v.52 no.2
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• pp.109-111
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• 2019

We report the case of a female patient who underwent late reoperation following endocarditis surgery. The patient first underwent surgery at 22 years of age for endocarditis with aortic and tricuspid insufficiency. She underwent aortic root replacement with a homograft and tricuspid valve replacement with a tissue valve. Coronary artery bypass using the internal thoracic artery and ligation of the left main coronary artery were performed. Ten years later, failure of the homograft and the tricuspid valve developed. In the second operation, the patient underwent a successful Bentall operation and tricuspid valve replacement with a mechanical valve under deep hypothermia and retrograde cold cardioplegia without drainage.