• Journal of the Korean Society of Propulsion Engineers
• /
• v.26 no.1
• /
• pp.88-97
• /
• 2022

In this study, a vitiated air heater was designed and manufactured to supply high-temperature and high-pressure air to the ground test apparatus of a direct-connected supersonic combustor, and an experiment was performed to verify the target design point. By installing wedges at the upper boundary, lower boundary and center of the nozzle exit of the vitiated air heater, it was confirmed that the Mach number satisfies the 2.0 level, and the pressure of the combustion chamber was also satisfactory compared to the design point. In the case of temperature, the measured temperature deviation was large due to the degree of exposure of the thermocouple and the slow response characteristics. After that, the isolator was connected to the rear of the vitiated air heater, and the Mach number was measured in the same method, and the Mach number at the center of the isolator eixt was slightly reduced to 1.8~1.9.

• Proceedings of the KACD Conference
• /
• 2008.05a
• /
• pp.246-257
• /
• 2008

The purpose of this study was to investigate the influence of various occlusal loading sites and directions on the stress distribution of the cervical composite resin restorations of maxillary second premolar, using 3 dimensional (3D) finite element (FE) analysis. Extracted maxillary second premolar was scanned serially with Micro-CT (SkyScan1072; SkyScan, Aartselaar, Belgium). The 3D images were processed by 3D-DOCTOR (Able Software Co., Lexington, MA, USA). HyperMesh (Altair Engineering. Inc., Troy, USA) and ANSYS (Swanson Analysis Systems. Inc., Houston, USA) was used to mesh and analyze 3D FE model. Notch shaped cavity was filled with hybrid (Z100, 3M Dental Products, St. Paul, MN, USA) or flowable resin (Tetric Flow, Viva dent Ets., FL-9494-Schaan, Liechtenstein) and each restoration was simulated with adhesive layer thickness ($40{\mu}m$). A static load of 200 N was applied on the three points of the buccal incline of the palatal cusp and oriented in $20^{\circ}$ increments, from vertical (long axis of the tooth) to oblique $40^{\circ}$ direction towards the buccal. The maximum principal stresses in the occlusal and cervical cavosurface margin and vertical section of buccal surfaces of notch-shaped class V cavity were analyzed using ANSYS. As the angle of loading direction increased, tensile stress increased. Loading site had little effect on it. Under same loading condition. Tetric Flow showed relatively lower stress than Z100 overall, except both point angles. Loading direction and the elastic modulus of restorative material seem to be important factor on the cervical restoration.

• Restorative Dentistry and Endodontics
• /
• v.33 no.3
• /
• pp.246-257
• /
• 2008

The purpose of this study was to investigate the influence of various occlusal loading sites and directions on the stress distribution of the cervical composite resin restorations of maxillary second premolar, using 3 dimensional (3D) finite element (FE) analysis. Extracted maxillary second premolar was scanned serially with Micro-CT (SkyScan1072; SkyScan, Aartselaar, Belgium). The 3D images were processed by 3D-DOCTOR (Able Software Co., Lexington, MA, USA). HyperMesh (Altair Engineering, Inc., Troy, USA) and ANSYS (Swanson Analysis Systems, Inc., Houston, USA) was used to mesh and analyze 3D FE model. Notch shaped cavity was filled with hybrid (Z100, 3M Dental Products, St. Paul, MN, USA) or flowable resin (Tetric Flow, Vivadent Ets., FL-9494-Schaan, Liechtenstein) and each restoration was simulated with adhesive layer thickness ($40{\mu}m$). A static load of 200 N was applied on the three points of the buccal incline of the palatal cusp and oriented in $20^{\circ}$ increments, from vertical (long axis of the tooth) to oblique $40^{\circ}$ direction towards the buccal. The maximum principal stresses in the occlusal and cervical cavosurface margin and vertical section of buccal surfaces of notch-shaped class V cavity were analyzed using ANSYS. As the angle of loading direction increased, tensile stress increased. Loading site had little effect on it. Under same loading condition, Tetric Flow showed relatively lower stress than Z100 overall, except both point angles. Loading direction and the elastic modulus of restorative material seem to be important factor on the cervical restoration.

• Journal of Chest Surgery
• /
• v.29 no.1
• /
• pp.67-72
• /
• 1996

Bronchoesophageal fistula is a rare clinical entity whether congenital or acquired in adult. We experinced 8 cases of bronchoesophageal fistula and performed surgical correction from 1991 to 1994. Of the 8 patients, 5 patients were male and three were female aging from 21 to 61 years(mean 44.12$\pm$14.62 years). Seven of 8 patients had congenital bronchesophageal fistula and the other one had acquired bronchoesophageal fistula. According to the classification of Braimbridge and Keith, 4 cases were belonged to type I and 3 cases were type II . The diagnosis was confirmed by esophagogram in six patients, by bronchoscopy and bronchogram in two patients, and in one patient, the fistula was discovered i cidentally during operation. All patients received astulectomy and concomitant procedures were applied as follows ; 4 diverticulectomy, 4 right lower lobectomy, 1 bilobectomy, 1 left lower lobectomy and 1 wedge resection of left lower lobe. All but one patient were discharged without any complication and have been in good condition.

• Korean Journal of Optics and Photonics
• /
• v.19 no.3
• /
• pp.229-236
• /
• 2008

The optimum conditions of second harmonic generation (SHG) can be successfully achieved experimentally using single pass and double pass methods of a pumping beam. The beam has a power of several Watts radiated by a DOFA (Diode Laser Oscillator & Fiber Amplifier) system, which is a high power CW wavelength tunable infrared laser system, in a PPLN (Periodically Poled MgO doped Lithium Niobate) nonlinear crystal. In the case of a single pass method, the parameters are the wavelength of 535 nm for SHG and the output power of 245 mW generated from the pumping input beam with wavelength of 1070 nm and the power of 2.45 W at phase matching temperature of $108.9^{\circ}C$. The conversion efficiency of SHG was 10%. In order to enhance the output of SHG, the double pass method of the SHG system of a PPLN using a concave mirror for the retroreflection and a pair of wedged flat windows for phase compensation was also presented. In this double pass system, we obtained the SHG output beam with the wavelength of 535 nm and the maximum power of 383 mW at optimum phase matching temperature of $108.5^{\circ}C$ by using an incident pumping beam with wavelength of 1070 nm and the power of 2.45 W. The maximum conversion efficiency is 15.6%, which is more than that of the single pass method.

• Progress in Medical Physics
• /
• v.17 no.3
• /
• pp.131-135
• /
• 2006

A commercial ion chamber matrix was examined the characteristics and its performance for radiotherapy qualify assurance. The device was the I'mRT 2D-MatriXX (Scanditronix-Wellhofer, Schwarzenbruck, Germany). The 2D-MatriXX device consists of a 1020 vented ion chamber array, arranged in $24{\times}24cm^2$ matrix. Each ion chamber has a volume of $0.08cm^3$, spacing of 0.762 cm and minimum sampling time of 20 ms. For the investigation of the characteristics, dose linearity, output factor, short-term reproducibility and dose rate dependency were tested. In the testing of dose linearity. It has shown a good signal linearity within 1% in the range of $1{\sim}800$cGy. Dose rate dependency was found to be lower than 0.4% (Range: 100-600 Mu/min) relative to a dose rate of 300 Mu/min as a reference. Output factors matched very well within 0.5% compared with commissioned beam data using a ionization chamber (CC01, Scanditronix-Wellhofer, Schwarzenbruck, Germany) in the range of field sizes $3{\times}3{\sim}24{\times}24cm^2$. Short-term reproducibility (6 times with a interval of 15 minute) was also shown a good agreement within 0.5%, when the temperature and the pressure were corrected by each time of measurement. in addition, we compared enhanced dynamic wedge (EDW, Varian, Palo Alto, USA) profiles from calculated values in the radiation planning system with those from measurements of the MatriXX. Furthermore, anon-uniform IMRT dose fluence was tested. All the comparison studies have shown good agreements. In this study, the MatriXX was evaluated as a reliable dosimeter, and it could be used as a simplistic and convenient tool for radiotherapy qualify assurance.

• The Journal of the Petrological Society of Korea
• /
• v.9 no.2
• /
• pp.84-98
• /
• 2000

Daejeon-sa basalt in the Mt. Juwang area composed of 12 basalt flows alternate with 9 peperites and each basalt and peperite has the variety of thickness. Peperites yielded in Daejeon-sa basalt are mixed of basalt with reddish shale, of which textural type is globular peperite. Basalts yielded in Daejeon-sa basalt are massive basalt without vesicule, although sometimes vesicules are founded in upper within a flow unit. The basalt has mainly pseudomorph of olivine as phenocryst, and also plagioclase and clinopyroxene phenocryst. Matrix is mainly subophitic texture. The plotting result on the TAS diagram shows these basalts belong to the sub-alkaline, and it can be subdivided into calc-alkaline series on the basis of the diagram of Si02 vs. K20 and of alkali index vs. A1203 diagram. According to plots of wt.% oxides vs. wt.% MgO, abundances of A1203 and CaO increase with decreasing MgO while F ~ dOecre~ase . With decreasing MgO compatible elements decrease while incompatible elements increase. In spider diagram of MORB-normalized trace element patterns, HFS elements are nearly similiar with MORB, but LIL elements are enriched. Especially, contents of Ce, F: and Sm are enriched but Nb is depleted. In the chondrite-normalized REE patterns light REEs are enriched than heavy REEs. Tectomagmatic discrimination diagrams shows basalts in the study area are formed in the tectonomagmatic environment of subduction zone under continental margin. This result accord with characters of chemical composition mentioned above. Cr vs. Y diagram and CeM, vs. Ce diagram show that the primary magma of the basalts may formed by the about 15% partial melting of garnet-peridotite in the mantle wedge. After then, Daejeon-sa basalts may formed from evolved magma undergone mainly olivine fractional crystallization and contarnination of crustal materials before eruption.

• Progress in Medical Physics
• /
• v.21 no.1
• /
• pp.113-119
• /
• 2010

Software for GafChromic EBT2 film dosimetry was developed in this study. The software provides film calibration functions based on color channels, which are categorized depending on the colors red, green, blue, and gray. Evaluations of the correction effects for light scattering of a flat-bed scanner and thickness differences of the active layer are available. Dosimetric results from EBT2 films can be compared with those from the treatment planning system ECLIPSE or the two-dimensional ionization chamber array MatriXX. Dose verification using EBT2 films is implemented by carrying out the following procedures: file import, noise filtering, background correction and active layer correction, dose calculation, and evaluation. The relative and absolute background corrections are selectively applied. The calibration results and fitting equation for the sensitometric curve are exported to files. After two different types of dose matrixes are aligned through the interpolation of spatial pixel spacing, interactive translation, and rotation, profiles and isodose curves are compared. In addition, the gamma index and gamma histogram are analyzed according to the determined criteria of distance-to-agreement and dose difference. The performance evaluations were achieved by dose verification in the $60^{\circ}$-enhanced dynamic wedged field and intensity-modulated (IM) beams for prostate cancer. All pass ratios for the two types of tests showed more than 99% in the evaluation, and a gamma histogram with 3 mm and 3% criteria was used. The software was developed for use in routine periodic quality assurance and complex IM beam verification. It can also be used as a dedicated radiochromic film software tool for analyzing dose distribution.

• Tuberculosis and Respiratory Diseases
• /
• v.40 no.5
• /
• pp.565-574
• /
• 1993

Background: Pulmonary hamartomas are benign tumors that occur in the parenchyma or in the bronchi. They present as a solitary pulmonary nodule(SPN) or as a cause of bronchial obstruction. The incidence, once minimal, is increasing in Korea. To get clinical spectrum about the tumor, we analyzed all the reported cases in Korea since 1964. Methods: We reviewed the clinical, radiological and pathological findings of 13 patients of intrapulmonary or endobronchial hamartomas in Severance Hospital and of 38 reported cases in Korea published in literatures from 1964 to 1992 retrospectively. Results: Including 17 endobronchial hamartomas, 54 cases were studied. There were 25 men and 29 women, with a mean age of 47.2 years; 45.3 years in endobronchial type and 51.3 years in parenchymal type. Pulmonary symptoms were present in 8 patients (22%) of intrapulmonary type and in all patients of endobronchial type: cough (65%), dyspnea (53%), sputum (35%), fever (29%) in order. On chest X-rays, atelectasis was seen in 10 patients (59%) in endobronchial type; but SPN was noted in 36 patients (97%) of intrapulmonary type. Calcification was present in 7 intapulmonary hamartomas (23%); but is in 2 endobronchial hamartomas (12%). The diagnostic yield was 6 out of 14(43%) in endobronchial ones; 4 out of 7(57%) in intrapulmonary ones. Fifty patients underwent operations as follows: lobectomy (28), enucleation (8), resection (8), bilobectomy (4), pneumonectomy (2). The hamartomas were 1.2 times more common in the right lung; mean transverse diameter at the time of operation was 2.3 cm in endobronchial type, 3.8 cm in intrapulmonary ones. Chondroid components were present in 11(65%) of 17 endobronehial ones but in 30(91%) of 33 intrapulmonary hamartomas. No malignant changes were seen perioperative period and up to early 1993. Conclusion: The younger age in endobronchial hamartomas, the preponderance of the female sex and the more incidence in the right lung, and the diagnostic choice of lobectomies were different from the studies of the Western countries.

• The Journal of the Petrological Society of Korea
• /
• v.19 no.1
• /
• pp.19-30
• /
• 2010

The Jurassic Daebo Ogcheon granite is distributed in the Ogcheon area which is located in the central part of the Ogcheon Belt, Korea. This paper newly examines the timing of Honam shearing on the basis of the petrofabric researches on the deformation structures of the Ogcheon granite. The structural shape of Ogcheon granite is mainly characterized by a wedge shaped of E-W trend and an elongate shape of ENE trend in geological map and by contacts parallel to the regional S1 foliation in the host Ogcheon supergroup. It indicates that the pluton was permittedly emplaced after the S1 formation. The main deformation structures are marked by a solid-state tectonic foliation of N-S trend, which passes through the contact of the pluton, and by an aplitic dyke of E-W trend, and by sinistral, NW and E-W oriented shear zones on the eastern border of the pluton. The petrofabric study on the main deformation structures suggests that the tectonic foliation and the aplitic dyke were formed by the Honam dextral strike-slip shearing of (N)NE trend at ca. $500{\sim}450^{\circ}C$ deformation temperature, and that the sinistral shear zones could be induced by the dextral rotation of the pluton from its original site of intrusion, that is, by the shear strain which is due to sliding of the pluton past the host rocks. The history of emplacement and deformation of the Ogcheon granite and the previous results on the timing of Honam shearing would be newly established and reviewed as follows. (1) Early~Middle Jurassic(187~170 Ma); intrusion of syntectonic foliated granite related to Early Honam shearing, (2) Middle Jurassic(175~166 Ma); main magmatic period of Jurassic granitoids, the permitted emplacement of the Ogcheon granite, (3) Middle~Late Jurassic(168~152 Ma); main cooling period of Jurassic granitoids, the deformation of the Ogcheon granite related to Late Honam shearing. Thus, this study proposes that the Honam shear movement would occur two times at least during 187~152 Ma (ca. 35 Ma) through the intertectonic phase of 175~166 Ma.