• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 학술대회
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• pp.111-117
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• 2008

This paper reports briefly on the computational results of a turbulent Rayleigh-Benard convection with the elliptic-blending second-moment closure (EBM). The primary emphasis of the study is placed on an investigation of accuracy and numerical stability of the elliptic-blending second-moment closure for the turbulent Rayleigh-Benard convection. The turbulent heat fluxes in this study are treated by the algebraic flux model with the temperature variance and molecular dissipation rate of turbulent heat flux. The model is applied to the prediction of the turbulent Rayleigh-Benard convection for Rayleigh numbers ranging from $Ra=2{\times}10^6$ to $Ra=10^9$, and the computed results are compared with the previous experimental correlations, T-RANS and LES results. The predicted cell-averaged Nusselt number follows the correlation by Peng et al.(2006) ($Nu=0.162Ra^{0.286}$) in the 'soft' convective turbulence region ($2{\times}10^6{\leq}Ra{\leq}4{\times}10^7$) and it follows the experimental correlation by Niemela et al. (2000) ($Nu=0.124Ra^{0.309}$) in the 'hard' convective tubulence region ($10^8{\leq}Ra{\leq}10^9$) within 5% accuracy. This results show that the elliptic-blending second-moment closure with an algebraic flux model predicts very accurately the Rayleigh Benard convection.

• 대한두개안면성형외과학회지
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• 제18권2호
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• pp.112-116
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• 2017

The ideal scalp reconstruction involves closure of the defect with similar hair-bearing local tissue in a single step. Various reconstructions can be used including primary closure, secondary healing, skin grafts, local flaps, and microvascular tissue transfer. A 53-year-old female patient suffered glioblastoma, which had recurred for the second time. The neuro-surgeons performed radial debridement and an additional resection of the tumor, followed by reconstruction using a serratus anterior muscle flap with a split-thickness skin graft. Unfortunately, the flap became completely useless and a bilateral rotation flap was used to cover the defect. Two month later, seroma with infection was found due to recurrence of the tumor. Additional surgery was performed using multiple perforator based island flap. The patient was discharged two weeks after surgery without any complications, but two months later, the patient died. Radical surgical resection of tumor is the most important curative option, followed by functional and aesthetic reconstruction. We describe a patient with a highly malignant tumor that required multiple resections and subsequent reconstruction. Repeated recurrences of the tumor led to the failure of reconstruction and our strategy inevitably changed, from reconstruction to palliative treatment involving fast and stable wound closure for the patient's comfort.

• Journal of Chest Surgery
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• 제21권4호
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• pp.630-640
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• 1988

We clinically evaluated 222 cases of ventricular septal defect which we experienced at Department of Thoracic and Cardiovascular Surgery, Pusan National University Hospital between July 1981 and March 1988. These patients were occupied 46.2% of all congenital heart disease operated on its same period. Of 222 cases, 132 patients were male and 90 patients were female. Their age distribution ranged from 8 months to 34 years of age and their mean age was 10.3 years. Among these patients, 86 patients had associated cardiac anomalies, which were patent foramen ovale 43 cases[19.5%], Atrial septal defect 18 cases[8.1%], patent ductus arteriosus 8 cases[3.6%], aortic insufficiency 7 cases[3.2%], infundibular pulmonary stenosis 5 cases[2.3%] and etc. There was statistically significant correlationship between VSD size and Qp/Qs, Rp/Rs, Pp/Ps respectively. All cases were operated under cardiopulmonary bypass and 157 patients[70.7%] would be corrected through right atrial approach. 158 patients[71.2%] underwent closure of ventricular septal defect with primary closure and the remained patients[28.8%] with patch closure. In anatomical classification by Kirklin, type I constituted 23.4%, type II 73.4%, type III 0.5%, type I and type II 1.4%, and type II and type III 1.4%. Important postoperative EGG changes were noted in 57 cases[25.7%] and incomplete right bundle branch block was most common[12.6%]. 54 patients[24.3%] developed minor and major postoperative complications and 9 patients died of several complications and overall operative mortality was 4.1%.

• Archives of Plastic Surgery
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• 제46권2호
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• pp.167-170
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• 2019

Full-thickness scalp burns secondary to hair coloring are rare; however, such defects can be large and complex reconstruction of hair-bearing tissue may be necessary. Many skin-stretching devices that use gradual traction have been applied to take advantage of the viscoelastic properties of the skin. A 21-year-old female patient was seen with a burn defect on her occipital scalp leading to exposed subcutaneous tissue after chemical application of hair coloring in a salon. The dimensions of the wound were $10cm{\times}5cm$, and a skin graft or flap would have been necessary to close the defect. Two long transfixing K-wires (1.4 mm) and paired 3-wire threads (23 gauge), which are readily available in most hospitals, were applied over a period of 12 days for trichophytic closure of the defect. The remaining scalp scars after primary trichophytic closure with this skin-stretching method were refined with hair follicle transplantation. This skin-stretching method is simple to apply and valuable for helping to close problematic areas of skin shortage that would otherwise require more complicated procedures. This case shows a relatively unknown complication of hair coloring and its treatment.

• Journal of Chest Surgery
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• 제48권4호
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• pp.265-271
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• 2015

Background: Stainless steel wiring remains the most popular technique for primary sternal closure. Recently, a multifilament cable wiring system (Pioneer Surgical Technology Inc., Marquette, MI, USA) was introduced for sternal closure and has gained wide acceptance due to its superior resistance to tension. We aimed to compare conventional steel wiring to multifilament cable fixation for sternal closure in patients undergoing major cardiac surgery. Methods: Data were collected retrospectively on 1,354 patients who underwent sternal closure after major cardiac surgery, using either the multifilament cable wiring system or conventional steel wires between January 2009 and October 2010. The surgical outcomes of these two groups of patients were compared using propensity score matching based on 18 baseline patient characteristics. Results: Propensity score matching yielded 392 pairs of patients in the two groups whose baseline profiles showed no significant differences. No significant differences between the two groups were observed in the rates of early mortality (2.0% vs. 1.3%, p=0.578), major wound complications requiring reconstruction (1.3% vs. 1.3%, p>0.99), minor wound complications (3.6% vs. 2.0%, p=0.279), or mediastinitis (0.8% vs. 1.0%, p=1.00). Patients in the multifilament cable group had fewer sternal bleeding events than those in the conventional wire group, but this tendency was not statistically significant (4.3% vs. 7.4%, p=0.068). Conclusion: The surgical outcomes of sternal closure using multifilament cable wires were comparable to those observed when conventional steel wires were used. Therefore, the multifilament cable wiring system may be considered a viable option for sternal closure in patients undergoing major cardiac surgery.

• Journal of Chest Surgery
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• 제14권1호
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• pp.77-82
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• 1981

The esophageal perforation is the most rapidly fatal and most serious perforation of the gastrointestinal tract. The 53 year old male patient was admitted because of substernal and epigastric pain altar esophageal bougienage for the indigestion and the difficult swallowing before about 18 hours. On esophagogram, there was the extravasation of contrast media at the right side of the lower esophagus [retrocardiac segment]. The emergency thoractotomy, debridement and suture closure with drainage were performed. But after 7 days the esophageal leakage was complicated again with pus discharge, although primary repair was done. On the 13th hospital day, the temporary cervical esophageal fistulation with dual drainages was made under general anesthesia. On the 38th day after this procedure, the esophageal leakage was closed spontaneously. On the 63rd hospital day the cervical fistulation was repaired and ever since the esophageal passage was good without leakage or swallowing difficulty.

• 대한기계학회논문집
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• 제5권3호
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• pp.159-169
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• 1981

The mixing length theory is extended to close the momentum queations for two-phase turbulent flow at a first-order closure level. It is assumed that the mass fraction of the particles is of the order of unity, that the particle size is so small that the particles are fully suspended is the primary fluid, and that the relaxation time scale of the particles is of the same order as the time scale of the energy containing eddies so that the suspended particles are responsive to the fluctuating turbulent field. The bulk motion of the particles is treated as a secondary fluid with its own coefficient of momentum transport. The proposed closure is uniformly destributed acress the pipe section. Predicted velocity profiles and the friction factors are in good agreement with avaiable experimental data.

• Journal of Chest Surgery
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• 제17권2호
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• pp.197-204
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• 1984

The criss-cross, a term first used by Anderson and Ando , is a rare cardiac malformation in which the systemic and pulmonary blood streams cross at the atrioventricular level, without mixing. We have surgically experienced four cases of crossed atrioventricular connection, three concordant and one discordant, at Seoul National University Hospital from July 1982 to March 1984. The atrial situs, the atrioventriculoarterial connection, the spatial position of the ventricles, and associated cardiac anomalies were analyzed. We have performed right Blalock-Taussig shunt for case 1, modified Fontan operation for case 2, patch closure of VSD for case 3, and septation of common ventricle with primary closure of ASD for case 4. The relatively good postoperative results in these patients were gratifying and suggest that cardiac anomalies associated with this rare malformation can be successfully repaired without further risk. To our knowledge, this is the first report of surgical experience for criss-cross heart in the Korean literature.

• 대한음성학회지:말소리
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• 제33_34호
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• pp.43-55
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• 1997

This study examined one of the hypotheses on the consonant reduction in Korean inferred from the Articulatory Phonology framework through phonetic experiments: Degree of consonant reduction depends on the height of the neighboring vowels--the lower the height of the neighboring vowel is, the higher the degree of reduction of stop closure period is. The results of this study, in general, turned out to support the hypothesis with some cases requiring other phonetic considerations, e.g., rate of some tongue tip movement in the case of dental lenis stop /t/ or the facts that bilabial lenis stop /p/ share its primary articulators, lips, with the neighboring vowel /u/ and that for bilabial closure, the upper lip lowers more for compensation of little movement of lower lip when its raising gets disturbed for some reasons.

• 전자공학회논문지A
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• 제32A권4호
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• pp.15-23
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• 1995

In this paper, we evaluate the performance of a transient queueing approximation when it is applied to modeling computer communication networks. An operational computer network that uses the ISO IS-IS(Intermediate System-Intermediate System) routing protocol is modeled as a Jackson network. The primary goal of the approximation pursued in the study was to provide transient queue statistics comparable in accuracy to the results from conventional Monte Carlo simulations. A closure approximation of the M/M/1 queueing system was extended to the general Jackson network in order to obtain transient queue statistics. The performance of the approximation was compared to a discrete event simulation under nonstationary conditions. The transient results from the two simulations are compared on the basis of queue size and computer execution time. Under nonstationary conditions, the approximations for the mean and variance of the number of packets in the queue erer fairly close to the simulation values. The approximation offered substantial speed improvements over the discrete event simulation. The closure approximation provided a good alternative Monte Carlo simulation of the computer networks.