• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.2
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• pp.416-426
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• 1999

The objective of this study is to confirm the effect of dentine bonding primer application on penetration of sealant. Extracted permanent molars were used to compare penetration success rate of control group (sealant application only) and experimental groups (sealant application after applying the primers of $Scotchbond^{TM}$ Multi-Purpose system and $All-Bond^{(R)}$ 2 system). The following results were obtained: 1. The experimental groups using the primers showed increased sealant penetration success rate to the base of fissure when compared to control group but there was no statistically significant differences(p>0.05). 2. The depth, width and 'depth/width' value of fissure had statistically significant effect on sealant penetration success rate(p<0.05). 3. The penetration success rate decreased about 0.9 times as the depth of fissure increased every $25{\mu}m$, and increased about 1.1 times as the width of the fissure orifice increased every $25{\mu}m$ and decreased about 0.6 times as the 'depth/width' value increased every 1. From the above results, it can be concluded that assure morphology had a great effect on sealant penetration and for better penetration, use of dentine bonding primer can be helpful but it needs more study in clinical bases.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.1
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• pp.114-118
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• 2009

Sialolithiasis is the formation of calcific concretions within the ductal system of major or minor salivary glands. The submandibular gland is most involved because of its high viscosity of the saliva and the long, curved duct. It may occur at any age but, it is most common in middle-aged adults and rare in childhood. Clinical symptoms in sialolithiasis are variable but, swelling is the most common, followed by the pain. Clinical examination and radiographic examination(panoramic and mandibular occlusal radiographs, sialography, intraoral-, extraoral- ultrasound, CT scan, MRI and sialoendoscopy) can help to confirm a diagnosis and localize a stone. The treatment is surgical intervention, either removal of the sialolith or sialoadenectomy. However, non-invasive techniques including shock-wave lithotripsy, $CO_2$ laser and endoscopic treatment used in selected cases. A 5-Year-old girl referred from private practice for evaluation of a yellowish mass on the floor of the mouth. She complained that it had became three times bigger than four months ago when it was found for the first time and she had some pain on submandibular gland area occasionally. On physical examination, a firm and yellowish mass could be seen at the orifice of the submandibular duct. Diagnosis is the submandibular sialolithiasis in the anterior Wharton`s duct. Under local anesthesia, stone was removed.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.6
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• pp.343-351
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• 2014

The reflection and transmission coefficients of waves due to perforated wall are mainly determined by both the porosity and wall thickness of the perforated wall and the period and nonlinearity of incident waves. Among them the wall thickness is very important because it affects the head loss coefficient and the inertia length of the wall. However, by employing the head loss coefficient derived for sharp crested orifice, the previous researches have neglected, or incorrectly considered the effect of wall thickness on the head loss coefficient. Even though it is considered, the effect of the inertia length is neglected in some empirical formulae. Thus, the effect of wall thickness on the reflection and transmission coefficients of waves is not properly considered. In this study comprehensive experiments are conducted for the perforated walls with various thicknesses, and the results are compared with those predicted by the empirical formulae. As a result it is found that the existing formulae can not properly consider the effect of wall thickness, and it is confirmed that a new formula which can correctly consider the effect of wall thickness on the head loss coefficient is necessary.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.4
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• pp.299-304
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• 2013

The HAN which is an ionic liquid is a non-toxic monopropellant with high storability, and its specific impulse can be increased by blending methanol, thereby it can substitute the hydrazine. The HAN was synthesized by acid-base reaction of hydroxylamine and nitric acid, and the blending ratio of HAN and methanol is 8.2:1. The iridium catalyst was used to decompose the HAN, and 1 N class thruster with shower head type injector having one orifice was used to evaluate the HAN/Methanol propellant. The thermal stability of distributor was increased by using ceramic material to endure the high temperature of product gas. The preheating temperature of catalyst should be $400^{\circ}C$ at least for the complete decomposition. The feeding pressure should be increased to increase the $C^*$ efficiency, thereby the decomposition performance was decreased upstream catalyst, and the performance of thruster was decreased. The fine metal mesh was inserted after the injector to improve the atomization of propellant, thereby it can settle the performance decrease problem. The phenomenon of performance decrease was remarkably improved owing to the insertion of fine metal mesh.

• Journal of Chest Surgery
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• v.8 no.2
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• pp.109-118
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• 1975

This is a report on four cases of the lobar emphysema due to proximal bronchial obstruction in the Department of Thoracic Surgery, Hanyang University Hospital, during the period of three and half years from 1972 to 1975. First case, a two years old male child was referred to our Department with the lobar emphysema of the lower lobe of the right lung with pneumonia. This emphysema was developed after aspiration of a piece of peanut. Bronchoscopy revealed that the bronchus of the right lower lobe was obstructed with the foreign body, however removal of the peanut through bronchoscope was not attempted because of corruption and softening of the peanut. The removal of the peanut by bronchotomy was performed after subsiding of acute phase of pulmonary infection. Postoperative course was uneventful and the emphysema was disappeared. Second case, a twenty months old female baby was referred to our Department with lobar emphysema of the lower lobe of the left lung. The emphysema was suddenly developed with coughing and dyspneic symptoms and the diagnosis was made roentgenologically. She gave a history of reccurrent infections of the respiratory tract after birth. Bronchoscopy showed an obstruction of the left main bronchus with the growing of fibrinous tissue on the bronchial mucosa. The protruded tissue in the left main bronchus taken out about O.8ml with biopsy forceps for histological examination. After this procedure, the emphysema of the left lung was disappeared. Histological finding was reported to be a chronic inflammatory granulation tissue. Third case, a two and half years old male child was referred to our Department with roentgenological lobar emphysema. Two weeks prior to admission he had an episode of sudden onset of coughing attack with dyspnea. Bronchoscopy revealed that the bronchus of the left lower lobe was obstructed with a mass which was strongly suspected of a neoplastic tissue. At operation, there was found a perforation of enlarged tuberculous lymph node in the bronchus of the left lower lobe and protrusion of granulation tissue into the bronchus. Ruptured orifice on themembranous wall of the left lower lobe bronchus was closed with interrupted suture after the" removal of a perforated tuberculous lymph node. Postoperative course was uneventful and antituberculous chemotherapy was given. Fourth case, a 47 years old man was admitted to our Department with the complaint of severe dyspnea of few months duration. Twenty years ago, he had a history of lung tuberculosis and was treated for many years. X-ray examination including tomography and bronchography revealed that the upper lobe of the right lung was destroyed with cavities, the lower lobe was completely shrunk, and the right middle lobe was strongly overdistended with narrowing bronchial trees. Differential bronchospirometry and lung scanning confirmed that the respiratory function of the affected lung was impaired almost totally. The value of the right lung was calculated on 6% of oxygen uptake, 1% of Minute volume, and 32% of vital capacity. The right pneumonectomy was performed under the careful consideration of anesthetic and surgical procedures. Postoperative course was uneventful and the respiratory function was improved nearly to the normal level.evel.

• Journal of Bio-Environment Control
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• v.6 no.3
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• pp.183-189
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• 1997

This study was performed to Investigate size of droplet sprinkled from mini-sprinkler. Twelve different kinds of the sprinkler having various structures and sizes of nozzle orifices were selected and tested. Diameters of the droplet reached at several distances from a sprinkler were measured by a machine vision system and the volume median diameters (VMM) were determined statistically. The size of droplet was not affected much by the size of nozzle orifice of a sprinkler but was rather more affected by structure of the sprinkler, especially by the shape of spreader of the sprinkler. Experiment of varying pressure of sprinkling water validated that the size of droplet was inversely proportional to water pressure powered by 1/3. Hence the size of droplet at any water pressure could be easily estimated from experimental data. The size of droplet increased as travel distance of the droplet increases in a relationship of and order function. The size of droplet of the tested sprinkler were in the ranges of 100-300fm within 1m of droplet travel distance, 230~470${\mu}{\textrm}{m}$ within 1~2m of droplet travel distance and 300~770${\mu}{\textrm}{m}$ within 2~3m of droplet travel distance.

• Journal of the Korean Institute of Gas
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• v.5 no.1
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• pp.45-51
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• 2001

Catalytic combustion is the environmental-friendly technology, which has been applied to a variety of areas for industrial and domestic use in recent years. Accordingly, this study performed the development of the catalytic manufacturing technology for the high temperature and of the catalytic combustor in priority, which were aimed to be aimed to a commercialized condensing boiler. Palladium(Pd) of a noble meta] was used as a catalyst for the high temperature and supported on $alumina(Al_{2}O_{3})\;and\;zirconia(ZrO_2)$ in constant weight ratio. Activity of Pd catalysts is compared and analysed in the catalytic combustion of natural gas. The ratio of $Pd/Al_{2}O_{3}\;=\;4$ was found to be better than any other weight ratios in activity and durability. The performance examination of catalysts and of combustion through the plate-type combustor made it possible to be developed the cylindrical-type combustor which has increased combustion area. Catalytic combustion condensing boiler of 25,000 kcal/hr class was also developed, which had the optimum combustion condition at the no221e of 5.95mm and the orifice of 21mm. This condition was determined through the performance experiments of catalytic combustion condensing boiler to which the cylindrical-type catalytic combustor was applied.

• Journal of Chest Surgery
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• v.31 no.8
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• pp.763-769
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• 1998

Background: Supravalvular aortic stenosis is a rare form of congenital cardiac anomaly involving ascending aorta distal to coronary orifice. Materials and methods: We operated 12 cases of supravalvular aortic stenosis between July 1986 and March 1997. Age ranged from 4 to 17(mean 10.2) years and 11 of them were male. Nine patients had clinical features of Williams syndrome. We experienced two types of supravalvular aortic stenosis, including 10 hour glass type and 2 diffuse type. Results: Preoperative transaortic pressure gradient ranged from 40 to 180(mean 92) mmHg by cardiac catheterization. Pulmonary stenosis was associated in 5 and 2 of them required angioplasty. Operative techniques included 6 standard aortoplasty with elliptical patch, 4 extended aortoplasty with inverted Y shaped patch, and 2 modified Brom's repair. There were no operative deaths. Postoperative echocardiographic evaluation was done at a mean interval of 12 months. Grade I or II aortic regurgitation was found in 3 cases. Postoperative cardiac catheterization revealed a mean transaortic pressure gradient of 26 (range 0 to 75) mmHg. A mean pressure drop was 78(range 30 to 114) mmHg. All patients were followed up for a mean of 40(range 1 to 67) months with uneventful clinical course. Conclusions: Our data proved the low mortality and excellent hemodynamic improvement after surgical relief of supravalvular aortic stenosis in children.

• Journal of Chest Surgery
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• v.35 no.10
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• pp.755-759
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• 2002

A 64-year-old man was admitted for gross hematuria. Preoperative study revealed right renal cell carcinoma with inferior vena cava(IVC) tumor thrombus. Right radical nephrectomy was performed, and deep hypothermic circulatory arrest(DHCA) with retrograde cerebral perfusion(RCP) was used for extraction of tumor thrombus in the IVC. The thrombus originated from the right kidney, which extended the orifice of the gonadal vein in the left renal vein laterally, the hepatic vein superiorly, and 3cm below the right renal vein inferiorly. The thrombus was removed completely without caval wall injury under DHCA with RCP, and the postoperative course was uneventful. He received immunotherapy with interferon, and followed up without any surgical problem.

• Journal of Chest Surgery
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• v.35 no.10
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• pp.750-754
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• 2002

Primary cardiac tumors are rare and about 20~25% of primary cardiac tumors are malignant. Moreover, primary malignant mesenchymoma of the heart is extremely rare. Recently, we have experienced two cases of cardiac malignant mesenchymoma. In the first case, malignant mesenchymoma which was originated from the posterior wall of the left atrium obstructing the mitral orifice was revealed pathologically in a 61-year-old woman with mitral regurgitation. The mass, which was 2.7$\times$3.7cm in size on the posterior wall of left atrium, was extended to the posteromedial commissure and annulus of the mitral valve. The mass was resected partially without excision of the left atrial free wall. She was discharged after 30 days without any problems and she received chemotherapy and followed up for 19months. The second case was a 4$\times$5cm in size, friable, yellow-whitish multilobulated mass in the left atrium which was originated from the left lower pulmonary vein. Multiple minor tumor nodules were found in the wall of the left atrium and the posterior leaflet of mitral valve. Partial mass excision and mitral valve replacement were performed.