• Journal of Chest Surgery
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• v.12 no.3
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• pp.207-214
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• 1979

This 3-year-old girl was observed frequent exertional dyspnea and cyanosis at crying since birth. She was not premature baby and delivered at full term normally. On physical examination, she was underdeveloped-body weight 13.5 kg, height 99 cm.- and cyanotic. There was severe clubbing on fingers. There was grade II/VI ejection systolic murmur on left lateral border of the sternum. The preoperative examinations [EKG, echocardiogram, cardiac catheterization and biventriculogram] showed that complicated T.G.A. combined vena cava[S.D.D.]. Preoperatively, we decided the corrective surgery of Rastelli operation using a. pulmonary valved conduit. The operation was performed under total circulatory arrest using deep profound hypothermia combining with extracorporeal circulation. On operation, the anatomy of the heart showed that, 1. The subaortic conus was seen and subaortic muscles were hypertrophied. 2. The VSD[type II], behind the subaortic conus-about 1 cm. in diameter, was visible only through LV cavity and, 3. The pulmonary valve ring was hypoplastic and pulmonary valvular stenosis was seen also. The subpulmonic area [LV outflow tract] was obstructed with hypertrophied muscle and mitral valve. 4. Left superior vena cava was drained to RA via coronary sinus. 5. LAD coronary artery was originated from right coronary artery and ran anterior to the pulmonary artery. According to above anatomy, we performed the VSD closure with Teflon patch, and Mustard operation combined with LV-to-pulmonary artery bypass graft using the valve contained [Hancock 16 mm] conduit. Postoperatively, adequate blood pressure could be maintained under the state of using inotropic agent [epinephrine]. On the second postoperative day, the patient died of cardiac arrest due to low cardiac output syndrome, acute renal failure and pulmonary edema.

• Journal of Chest Surgery
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• v.30 no.12
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• pp.1167-1174
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• 1997

We retrospectively reviewed a series of 20 patients treated with delayed sternal closure during a 5-year period from 1991 to 1996. Of the 2675 patients with cardiovascular su gery 20 underwent this procedure. Male and female ratio was 11:9, mean age was 6.4 months(range 7 days to 5 years). The indications included unstable hemodynamic profiles after open heart surgery due to myocardial edema and poor lung compliance(15), necessity of mechanical ventricular assist device due to weaning failure(3), and hypoxia after PAB(2). Sternum was closed at a mean interval of 102(range 4 to 213) hours after operation. During delayed sternal closure, central venous pressure was elevated(p<0.05). Mediastinitis and other wound problems did not occur. Sepsis developed in 2 patients and microorganism was confirmed in one of the two patients. Five patients died(mortality 25%). And two of 15 discharged patients died during follow-up period. Cumulative survival rate was 65.0% at 12 months and also 65.0% at 24 months.(Standard error was 10.7%) Delayed sternal closure Is considered to be a good method to decompress the hemodynamically compromised heart. Without that, it is not f asible to come off bypass or to decompress the heart. Of course. careful selection of the indication is imperative.

• Journal of Chest Surgery
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• v.45 no.2
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• pp.91-94
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• 2012

Background: Despite improved managements for acute respiratory distress syndrome (ARDS), its mortality remains high. Extracorporeal membrane oxygenation (ECMO) has emerged as the final option for the treatment of ARDS unresponsive to conventional measures. This study describes our experiences of venovenous ECMO support for the treatment of ARDS. Materials and Methods: Between 2007 and 2010, 56 patients (aged $56.6{\pm}13.4$ years, 43 males) received venovenous ECMO for the treatment of ARDS. The detailed clinical records were retrospectively reviewed. Results: Before the institution of ECMO support, 35 patients (55.4%) required nitric oxide inhalation, 35 patients (55.4%) received continuous renal replacement therapy, and 20 patients (35.7%) were in shock status. The median duration of ECMO support was 164 hours (range, 5 to 1,413 hours). 27 (48%) patients could be successfully weaned from ECMO. Of them, 7 (13%) survived to discharge. On logistic regression analysis, a requirement for higher inspiratory pressure before ECMO support was the only significant factor that could predict ECMO weaning failure. Conclusion: The outcome of venovenous ECMO support for the treatment of ARDS was suboptimal. Further improvements in outcomes should be made through the accumulation of experience and establishment of a standardized protocol for the management of ECMO.

• Journal of the Korean Vacuum Society
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• v.16 no.5
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• pp.348-352
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• 2007

In submicron processes, the feature size of ULSI devices is critical, and it is necessary both to reduce the RC time delay for device speed performance and to enable higher current densities without electromigration. In case of contacts between semiconductor and metal in semiconductor devices, it may be very unstable during the thermal annealing process. To prevent these problems, we deposited tungsten carbon nitride (W-C-N) ternary compound thin film as a diffusion barrier for preventing the interdiffusion between metal and semiconductor. The thickness of W-C-N thin film is $1,000{\AA}$ and the process pressure is 7mTorr during the deposition of thin film. In this work we studied the interface effects W-C-N diffusion barrier using the XRD and 4-point probe.

• Journal of the Korean Society for Nondestructive Testing
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• v.36 no.6
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• pp.496-503
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• 2016

Leakages at plant structures of power and petrochemistry plants have led to casualties and economic losses. These leakages are caused by fatigue failure of pipelines and their wall thickness. Vibration measurement methods for plant pipelines mainly use acceleration and laser sensors. These sensors are difficult to install and operate and thus lead to an increase in operational cost especially for wide area surveillance. Recently, measurements of leak and vibration displacements using cameras have attracted the interest of many researchers. This method has advantages such as simple installation, long distance monitoring, and wide area surveillance. Therefore, in this paper, we have developed a system that can measure the leakage and vibrational displacement by using a camera. Furthermore, the developed system was verified with experimental data.

• Journal of Chest Surgery
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• v.15 no.4
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• pp.432-439
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• 1982

Congenital posterolateral diaphragmatic hernia [Bochdalek hernia] is the result of a congenital diaphragmatic defect in the posterior costal part of the diaphragm in the region of the tenth and eleventh ribs. There is usually free communication between the thoracic and abdominal cavities. The defect is most commonly found on the left [90%], but may occurs on the right, where the liver often prevents detection. The male to female ratio is 2:1. Owing to the negative intrathoracic pressure, herniation of abdominal contents through the defects occurs, with resultant collapse of the lung. Shifting of mediastinum to the opposite side and compression of the opposite lung occurs. Most often these hernias are manifestated by acute respiratory distress in the newborn. A second, but less well recognized, group of patient with Bochdalek hernia survive beyond the neonatal period, usually present at a later time with "failure of thrive, intermittent vomiting, or progressive respiratory difficulty. " The diagnosis can often be made on clinical ground from the presence of respiratory distress, absence of breath sounds on the chest presence of bowel sounds over the chest . Roentgenogram of the chest confirm the diagnosis. Obstruction and strangulation have been reported but are rare. Treatment consists of early reliable identification of these congenital diaphragmatic hernia with high risk and surgical repairment. and postoperative pharmacological management with extracorporeal membranous oxygenation [=ECMO] support in the period of intensive care. On the surgical approach, for defects on left side, an abdominal incision is preferred, because of the high incidence of malrotation and obstructing duodenal bands. In the neonate, the operative mortality may be appreciable, but, later repair almost always is successful. During the period from 1972 to 1982, 4 cases of congenital Bochdalek hernia were experienced at the Kyung-Hee University Hospital.

• Journal of Chest Surgery
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• v.24 no.4
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• pp.323-330
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• 1991

Residual significant tricuspid regurgitation after mitral valve operation may significantly increase postoperative morbidity and mortality. However, routine techniques to detect tricuspid regurgitation preoperatively and postoperatively are not accurate. Doppler echocardiography was performed preoperatively and postoperatively to assess its ability to evaluate and quantify the severity of tricuspid regurgitation. In 34 patients with tricuspid regurgitation secondary to mitral valvular disease the tricuspid regurgitations were semiquantified on a scale of 1 to 3+. The 34 patients were divided into two groups on the basis of severity of tricuspid regurgitation as assessed by preoperative Doppler echocardiography. Group I [8 patients] had mild[1+] regurgitation, and group II [26 patients] had moderate to severe[2 ~ 3%] tricuspid regurgitation. In all studied patients, preoperative Doppler echocardiographic studies for the degree of tricuspid regurgitation were correlated with clinical symptoms[including NYHA class] and hemodynamics[JVP and right ventricular systolic pressure], and used as the indicator to determine whether tricuspid annuloplasty should be performed or not. Patients with significant tricuspid regurgitation[group II ] had greater preoperative right ventricular systolic pressures and NYHA classes, although there was no correlation between them. The 8 patients with mild[1+] tricuspid regurgitation[group I ] didn`t undergo any procedure for the tricuspid regurgitation and their postoperative Doppler echocardiographic studies showed the less than mild[0 ~ 1+] tricuspid regurgitation, and the 26 patients with significant[>2+] tricuspid regurgitation, and the 26 patients with significant[>2+] tricuspid regurgitation[group II ] underwent tricuspid annuloplasty for the tricuspid regurgitation and the postoperative Doppler echocardiographic studies showed the findings similar to group I except 1 patient who underwent Carpentier`s ring annuloplasty and had severe right ventricular failure. Therefore, preoperative Doppler echocardiography can accurately assess the relative severity of tricuspid regurgitation. Importantly, postoperative Doppler echocardiography could conveniently determine the effect of tricuspid annuloplasty for the patients with significant tricuspid regurgitation. Doppler echocardiography may be an important diagnostic method both for evaluating the degree of residual tricuspid regurgitation after left heart operation as well as for determining which patients should undergo tricuspid valve repair.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.10
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• pp.1227-1234
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• 2012

In this study, fatigue tests were carried out using real-scale pipe bend specimens with wall-thinning defects under a cyclic bending load together with a constant internal pressure of 10 MPa. The wall-thinning defect was located at the extrados and the intrados of the pipe bend specimens. A fully reversed cyclic in-plane bending displacement was applied to the specimens. For the pipe bends with wall thinning at the extrados, an axial crack occurred at the crown of the pipe bend rather than at the extrados where the defect was located. In addition, the fatigue life was longer than that of a sound pipe bend predicted from the design fatigue curve in ASME Sec.III, and it was less dependent on the axial length of the wall-thinning defect. For the pipe bends with wall thinning at the intrados, a circumferential crack occurred at the intrados. In this case, the fatigue life was much shorter than that of a sound pipe bend predicted from the design fatigue curve, and it clearly decreased with decreasing axial length of the wall-thinning defect.

• The Journal of Engineering Geology
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• v.16 no.3 s.49
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• pp.275-282
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• 2006

This study was conducted laboratory flume tests to identify landslide features and flow characteristics of debris using a flume test equipment. Under the several test conditions dependent on rainfall intensity and slope angle, the authors measured pore water pressure, slope failure and displacement, spreading area of debris on a regular time interval. The test processes were also recorded by video cameras and digital still cameras. According to the test results, pore water pressures have trends of direct proportion to the rainfall intensity and the slope angle, resulting in high potential of landslide triggering. The spreading area of debris is also increased with the slope angle and the rainfall intensity as well as the rainfall duration.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.4742-4748
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• 2014

A semi-automatic clutch was developed for drivers of vehicles with manual transmission. The clutch is operated by pressing a switch on the gear stick without stepping on a clutch pedal when the driver wants to shift gears. To automatic control a clutch, driving information is provided by sensors installed under the vehicle. On the other hand, sensors are prone to failure under severe driving conditions and a long time is needed to install or repair these sensors in the vehicle. In this paper, a semi-automatic clutch that received driving information by CAN communication from the ECU was developed and a pneumatic actuator was used to operate the clutch. The semi-automatic clutch by a pneumatic cylinder was operated with a supply air pressure of more than 3bar.