• Journal of Chest Surgery
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• v.19 no.4
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• pp.644-662
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• 1986

Seventy cases of open heart surgery were performed in the department of Thoracic and Cardiovascular Surgery, Pusan Paik Hospital, Inje College, from Oct. 1985 to Oct. 1986. And the results were summarized as follows. 1. Among the 70 cases, there were 48 cases of congenital heart anomalies and 22 cases of acquired rheumatic valvular heart diseases. Age range of the congenital patients was 7 months to 31 years with the mean age of 10 years, and the acquired patients was 18 to 62 years with the mean age of 40 years. 2. The heart-lung machine used for cardiopulmonary bypass was Sarns 7000, 5-head roller pump, and the number and type of oxygenators were 5 of membrane type and 65 of bubble type. For all cases GIK [glucose-insulin-potassium] solution was used as cardioplegic solution for myocardial protection during operation. 3. Among the 48 congenital anomalies, there were 12 cases of ASD group, 29 of VSD group, 3 of ECD, 3 of TOF and one of PDA + MR, and to all of which the appropriate radical operations were applied. 4. Among the 22 acquired valvular diseases, there were 11 cases of mitral valve diseases [MS; 4, MSr; 3, MRs; 4], 3 cases of aortic valve diseases [AR:1, ARs;1, ASr;1], 4 cases of double valve diseases [MRs+TR; 3, MRs+ARs; 1] and 4 cases of triple valve diseases [MSr+ASr+TR; 3, MSr+Ar+TR; 1]. To all the diseased mitral and aortic valves, artificial valve replacement was applied except one [As], in which valve plication was applied. And to all the diseased tricuspid valve, DeVega annuloplasty was applied. 5. The number of replaced artificial valves were 29 in 25 patients [congenital; 3, acquire; 22]. In MVR, 6 of mechanical valves [St. Jude Medical valve; 6] and 15 of tissue valves [Carpentier-Edward valve; 11, lonescu-Shiley valve; 4] were used. In AVR, 6 of mechanical valves [St. Jude Medical valve; 6] and 2 of tissue valves [Carpentier-Edward valve; 2] were used. 6. Postoperative complications were occurred in 12 cases. Among them 11 cases were recovered with intensive cares, but one patient [VSD + Fistula of Valsalva sinus] was expired with low cardiac out put syndrome.

• Journal of Chest Surgery
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• v.24 no.3
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• pp.265-270
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• 1991

Since advent of the prosthetic cardiac valve replacement, much efforts for accurate assessing value function in-vivo have been attempted. To evaluate the postoperative functional and morphological status of the replaced cardiac valve prosthesis, 33 patients with valve replacement were studied by transthoracic and transesophageal 2-dimensional echocardiac imaging as well as by color Doppler flow velocity imaging. Twenty four patients had mitral valve replacement. 6 patients had aortic valve replacement and 3 patients had both mitral and aortic valve replacement. There were 34 mechanical and 2 biological prosthesis. Comparing to transthoracic echocardiography, transesophageal approach showed transvalvular regurgitant jet flow amid the prosthetic mitral valve ring during. systole and much clear visualization of cardiac chamber behind prosthesis which could give shadowing effect to ultrasound beam. According to the quantitative grading by the length and area of mitral regurgitant flow, 24 out of 27 mitral valves revealed mild degree regurgitation considered as physiological after prosthetic bileaflet valve replacement and the other 3 valves including 2 biological prosthesis had moderate degree regurgitation which was regarded as pathologic one. 2 cases of left atrial thromboses and 1 case of paravalvular leakage which were not visible by transthoracic approach were identified by transesophageal echocardiography in patients with mitral valve replacement and patients with aortic valve replacement respectively. We conclude that in patients with prosthetic mitral valve replacement, transesophageal 2-dimensional imaging with color Doppler can suggest reliable information beyond that available from the transthoracic access even though it gives patient some discomfort to proceed.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.3
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• pp.311-317
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• 2016

This paper presents the flow characteristics of a ball valve used for a gas pipeline. Understanding of the internal flow of a ball valve is an important to analyze the physical phenomena of the valve. Present experimental study was performed by IEC 60534-2-3, the international standard for an industrial control valve testing procedure. Pressure measured at upstream and downstream of the valve, flow-rate and gas temperature passing the inside of the gas pipeline were measured with respect to valve opening rates. Throughout the experimental measurement of the ball valve, empirical equation of the pressure drop between the ball valve according to the mass flow rates is successively obtained using a polynomial curve fitting method. In addition, flow coefficient for determining the valve capacity is also analyzed with respect to valve opening rates using the curve fitting method.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.8
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• pp.1097-1102
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• 2001

For the purpose of development of high performance gasoline engine, the design technique of the 5-valve(3 intake valves) combustion chamber for a subcompact vehicle has been studied. 3 intake valves cylinder heads were designed by using a 3-dimension CAD program, and steady state flow experiments have been performed with these model. The 5-valve engines, which have larger valve opening areas, have larger intake flow rates and higher flow coefficient than the 4-valve engines. The effects of intake port design parameters of a 5-valve engine on the intake flow rate and bore size were studied, and the design guidelines for the 5-valve engine were established.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.17 no.2
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• pp.75-82
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• 2021

The 3D printing technology is one of the fourth industrial revolution technology that drives innovation in the manufacturing process, and should be applied to nuclear industry for various purposes according to the manufacturing trend change. In nuclear industry, it can be applied to manufacture obsolete items and new designed parts in advanced reactors or small modular reactors (SMRs), replacing the traditional manufacturing technologies. A gate valve body was manufactured, which was obsolete in nuclear power plant, using DED(Directed Energy Deposition) metal 3D printing technology after restoring design characteristics including 3D design drawing by reverse engineering. The 3D printed valve body was assembled with commercial parts such as seat-ring, disk, stem, and actuator for performance test. For the valve assembly, including 3D printed valve body, several tests were performed, including pressure test, end-loading test, and seismic test according to KEPIC MGG and KEPIC MFC. In the pressure test, hydraulic pressure of 391kgf/cm² was applied to 3D printed valve body, and no leak was detected. Also the 3D printed valve assembly was performed well in end-loading and seismic tests.

• Journal of Chest Surgery
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• v.31 no.3
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• pp.247-254
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• 1998

A total of 172 cases of MVR using the St. Jude Medical valve was conducted in the period from August 1986 to May 1996. The hospital mortality rate was 3.5% (n=6) and the late mortality rate was 3.3% (n=5). According to the follow-up of 161 surviving patients, the average length of survival was 50.23$\pm$0.27 months. Three cases of prosthetic valve related complication deaths were identified. Two cases could be ascribed to left atrial thrombi and resulting cerebral infarction, and one case was prosthetic valve endocarditis. Two cases were caused by hemorrhagic complications that we presume to have been accompanied by anti-coagulation therapy. The actuarial survival rate of all cases at 10 years was 92.3%. We conclude that good clinical results and a low complication rate could be achieved through mitral valve replacement with the St. Jude Medical valve. We also conclude that mid-term and long-term follow-ups were instrumental and necessary.

• Journal of Chest Surgery
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• v.8 no.2
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• pp.89-100
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• 1975

Sixteen cases of cardiac valve replacements have been done in this department since 1970. Twelve cases of mitral valve replacement were done with Beall valve, 2 cases of aortic valve replacement with Starr-Edwards and Magoven valve and 2 cases of double valve replacement using Beall valve for mitral and Magovern valve for aortic. Three patients [18.8%] died during operation. Two cases [12.5%] of hospital mortality occurred because of congestive heart failure and asphyxia due to tracheomalacia 3 months after operation. Follow-up studies from two to 27 months showed excellent results except three cases of late mortality [18.8 %]. Thromboembolism occurred in two double valve replacement patients[12.5%]who were fatal.

• Solar Energy
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• v.16 no.2
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• pp.97-112
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• 1996

The purpose of research is to complement the circulating pump of gas boiler for the domestic and to develop a pump housing with internal three way valve: Housing and three way valve have been apart in the existing pump system. Based on the experimental result on can-typed circulating pump with existing housing, a new housing with internal three way valve was designed and manufactured. The performance of can-typed circulating pump with the new housing, and the performance of circulating pump of boiler system were tested. As a result ot the test, the new housing with internal three way valve has been excellent in respect of pump performance, weight and manufacturing cost. So It is expected to have an effect of import substitution.

• Journal of Chest Surgery
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• v.24 no.10
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• pp.979-986
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• 1991

From October 1988 to November 1989, seven patients underwent valve replacement during the active phase of native valve endocarditis. There were 4 males and 3 females whose mean age was 41 years[range, 16 to 68 years]. Preoperative two-dimensional and Doppler echocardiography showed vegetations and severe valvular regurgitation in all patients. Blood cultures were positive in 4, and negative in 3 patients Organisms were alpha-hemolytic Streptococcus in 2, Staphylococcus epidermidis in 1, Erysipelothrix rhusiopathiae in 1 patient Valve tissue cultures were negative in all patients. Intravenous antibiotic therapy had been done for 3 to 18 days in 5 patients pre-operatively and was not done in 2 patients, Indications for operation were heart failure in h, and systemic emboli in 1 patient. The aortic valve was involved in 3, mitral in 1, and both aortic and mitral in 3 patients, One operative death[14.4%] occurred in patient with cardiogenic shock before operation. Late death occurred in one on 14 months after operation. The remaining 5 patients were followed up over a two year period in good condition. In conclusion, native valve endocarditis with severe heart failure must be considered for early operation.

• Journal of Chest Surgery
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• v.25 no.12
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• pp.1556-1562
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• 1992

Forty two consecutive patients who had had valve replacement with St. Jude Medical prosthesis were studied on a view point of intravascular hemolysis. Patients were consisted of 14 mitral valve replacement, and 7 aortic valve replacement, and 21 double, mitral and aortic, valve replacement. Serum LDH, indirect bilirubin, GOT, hemoglobin levels and ret-iculocyte count were pursued in postopeative 1st day, 3rd day, 7th day, 14th day and 21th day. Postoperatively, all patients were not detected paravalvular leakage on the ech-ocardiographical study. The patients with double valve replacement revealed higher levels of LDH on postopeative 14th day[P<0 05] than those with single valve replacement. Among the patients with single valve replacement, the patients with aortic valve replacement revealed slightly higher levels of entire postopeative data, but considered insignificant. There was correlation between the severity of hemolysis and the size of replaced aortic valve. In the postoperative LDH levels, the patients with small sized-aortic valve[less than 21mm in diameter] replacement revealed higher levels of postoperative 3rd day, 7th day and 14th day than those with large size[more than 23mm in diameter]. The patients with high level LDH of greater than 800 WU /L on postoperative 7th day were 61.9%[26 of 42]. The high LDH frequency of DVR was 71.4%[15 of 21], MVR 50.0%[7 of 14] and AVR, 57.1%[4 of 7]. The level of LDH declined gradualiy thereafter through postoperative 3 weeks. In conclusion, intravascular hemolysis after prosthetic valve replacement was dependent on position of valve replacement and size of valve. And this study supports the conventional valve selection and usage in our hospital. The patients with subclinical hemolysis after valve replacement should be placed on a close observation.