• Journal of the Korean Magnetics Society
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• v.9 no.2
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• pp.98-103
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• 1999

We have studied changes of coercivity $(H_c)$, exchange anisotropy field $(H_{ex})$ and MR ration in glass/Ta/NiFeI/CoI(t)/Cu/CoII(3/4 t)/NiFeII/FeMn spin valve structures by changing Ar pressure and thicknesses of Co layers using DC, RF sputtering methods. We obtained minimum coercivity of 2.8 Oe at 4 mTorr of Ar pressure, exchange anisotropy field of 50.0 Oe at 6 mTorr and 5.3 % of MR ratio at 10 mTorr. Also, we obtained 3.0 Oe of coercivity at 40 $\AA$ of CoI layer, 65.9 Oe at 13 $\AA$ and 4.7 % of MR ratio at 27 $\AA$ and 34 $\AA$ by changing the thicknesses of Co layers.

• Journal of the Korean Magnetics Society
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• v.17 no.1
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• pp.22-25
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• 2007

In this research, magnetic properties of spin valve structures using IrMn layers as antiferromagnetic were studied depending on the thickness of the pinned layer. The spin valve structure was Si substrate/$SiO_2(2,000\;{\AA})/Mo(17\;{\AA})NiFe(21\;{\AA})/CoFe(28\;{\AA})/Cu(22\;{\AA})/CoFe(18\;{\AA})/IrMn(t\;{\AA})/Ta(25\;{\AA})$. Also, Mo film was deposited on Si substrates and the thermal annealing effect was analyzed. The resistivity of the Mo film was increased as an annealing temperature was increased up to $600^{\circ}C$. The variations of MR ratio were related with magnetic exchange coupling field of the spin valve structures for various IrMn pinned layer thickness up to 130 ${\AA}$. MR ratio and $H_{ex}$ of spin valves was about 9.05% and 277.5 Oe when the thickness of the IrMn pinned layer was $32.5\;{\AA}(t=32.5\;{\AA})$. It was increased to 9.65% and 337.5 Oe for $t=65\;{\AA}$. For $t=97.5\;{\AA}$, the MR ratio and Hex decreased to 8.2% and 285 Oe, and further decrease was observed up to $t=130\;{\AA}$.

• Journal of Cardiovascular Imaging
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• v.31 no.1
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• pp.51-61
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• 2023

BACKGROUND: Valvular heart disease (VHD) is a common cause of cardiovascular morbidity and mortality worldwide; however, its epidemiological profile in Korea requires elucidation. METHODS: In this nationwide retrospective cohort study from the Korean valve survey, which collected clinical and echocardiographic data on VHD from 45 medical centers, we identified 4,089 patients with VHD between September and October 2019. RESULTS: The aortic valve was the most commonly affected valve (n = 1,956 [47.8%]), followed by the mitral valve (n = 1,598 [39.1%]) and tricuspid valve (n = 1,172 [28.6%]). There were 1,188 cases of aortic stenosis (AS) and 926 cases of aortic regurgitation. The most common etiology of AS was degenerative disease (78.9%). The proportion of AS increased with age and accounted for the largest proportion of VHD in patients aged 80-89 years. There were 1,384 cases of mitral regurgitation (MR) and 244 cases of mitral stenosis (MS). The most common etiologies for primary and secondary MR were degenerative disease (44.3%) and non-ischemic heart disease (63.0%), respectively, whereas rheumatic disease (74.6%) was the predominant cause of MS. There were 1,172 tricuspid regurgitation (TR) cases, of which 46.9% were isolated and 53.1% were associated with other valvular diseases, most commonly with MR. The most common type of TR was secondary (90.2%), while primary accounted for 6.1%. CONCLUSIONS: This report demonstrates the current epidemiological status of VHD in Korea. The results of this study can be used as fundamental data for developing Korean guidelines for VHD.

• Journal of the Korean Institute of Gas
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• v.19 no.6
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• pp.99-104
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• 2015

Today the most efficient way to transport the natural gas is carried via the liquid. In order to liquefy the natural gas to be cooled to $-160^{\circ}C$ or less. Cooling method has a number of different ways. In this paper, we studied control method for the representative liquefaction process, C3MR. Natural gas liquefaction control is a tool that can maintain the quality of natural gas is a means to ensure stable operation. Analyzing the C3MR process, and select the control parameters for the control valve. We find control structure for mixed refrigerant cycle through the step response. A control result obtained through the dynamic simulation arbitrarily given a disturbance was found to maintain a steady-state results.

• 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.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.313-317
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• 2001

Magneto-Rheological fluid (MR fluid) is known as a class of functional fluid with controllable apparent viscosity of the fluid by the applied magnetic field strength. Extensive researches with the functional fluids have been done on applications of the fluid to mechanical components such as suspension, absorber, engine mount, clutch, break, valve, etc. In this study, a new torsional damper using MR fluid is proposed, and the response property of the damper was theoretically investigated. The present damper is quit effective for reducing the driveline vibration in a wide range of the engine speed.

• Proceedings of the Korean Magnestics Society Conference
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• 1998.05a
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• pp.50-51
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• 1998

• Proceedings of the Korean Magnestics Society Conference
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• 2005.12a
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• pp.115-115
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• 2005

• Proceedings of the Korean Magnestics Society Conference
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• 2001.10a
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• pp.74-74
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• 2001

No Abstract, See Full-text

• Journal of Chest Surgery
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• v.21 no.2
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• pp.351-365
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• 1988

During one year[1987], 110 cases of open heart surgeries were performed in the department of Thoracic and Cardiovascular Surgery, Pusan Paik Hospital, Inje Medical College. And the results were summarized as follows. 1. Among the 110 cases, there were 77 cases of congenital heart diseases and 33 cases of acquired heart diseases. Age range of the congenital patients was 8 months to 30 years with the mean age of 8 years, and acquired patients was 16 to 56 years with the mean age was 32 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 50 of membrane type and 60 of bubble type. For all cases GIK[glucose-insulin-potassium] solution was used as cardioplegic solution for myocardial protection during operation. 3. Among the 77 congenital anomalies, there were 67 cases of acyanotic patients[ASD: 12, VSD: 50, PS: 1, AP window: 1, Gerbode defect: 1, ECD: 2] and 10 cases of cyanotic patients[TOF: 10], and to all of which the appropriate radical operations were applied. 4. Among the 33 acquired diseases, there were one case of left atrial myxoma, one of annuloaortic ectasia, 20 of mitral valve diseases[MS: 2, MSr: 8, MR: 2, MRs: 8], 9 of double valve diseases[MRs+AR: 1, MRs+ARs: 2, MRs+TR: 1, MSr+TR: 3, MSr+ASr: 1, MSr+ARs: 1], 2 of triple valve diseases[MSr+AR+TR: 1, MSr+ASr+TR: 1]. The left atrial myxoma was removed well with right atriotomy and atrial septal approach. And to the annuloaortic ectasia, Bentall operation was applied with good result. Mitral valve replacement[MVR] was applied to 20 cases of mitral valve diseases, double valve replacement[MVR+AVR] was applied to 6 cases of double valve diseases, MVR & tricuspid annuloplasty[TVA] was applied to 3 cases of mitral 5. The number of replaced valve were 39 in 31 cases. In MVR, 5 of mechanical valves[St. Jude Medical Valve] and 26 of tissue valves[Carpentier-Edward valve] were used. In AVR, 3 of mechanical valves and 5 of tissue valves were used. 6. Postoperative complications were occurred in 23 cases, and among them 21 cases were recovered with intensive cares, but 2 cases were expired[mortality: 1.8%].