• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.76-77
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• 2005

Single crystal $CuAlSe_2$ layers were grown on thoroughly etched semi-insulating GaAs(100) substrate at 410$^{\circ}C$ with hot wall epitaxy (HWE) system by evaporating $CuAlSe_2$ source at $680^{\circ}C$. The crystalline structure of the single crystal thin films was investigated by the photoluminescence(PL) and double crystal X-ray diffraction (DCXO). The temperature dependence of the energy band gap of the $CuAlSe_2$ obtained from the absorpt ion spectra was wel1 described by the Varshni's relation, $E_g$(T) = 2.8382 eV - ($8.86\times10^{-4}$ eV/H)$T_2$/(T + 155K). After the as-grown single crystal $CuAlSe_2$ thin films were annealed in Cu-, Se-, and Al-atmospheres, the origin of point defects of single crystal $CuAlSe_2$ thin films has been investigated by PL at 10 K. The native defects of $V_{cd}$, $V_{se}$, $Cd_{int}$, and $Se_{int}$ obtained by PL measurements were classified as donors or acceptors. And we concluded that the heat-treatment in the Cu-atmosphere converted single crystal $CuAlSe_2$ thin films to an optical n-type. Also. we confirmed that hi in $CuAlSe_2$/GaAs did not form the native defects because Al in single crystal $CuAlSe_2$ thin films existed in the form of stable bonds.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.11 no.6
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• pp.274-284
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• 2001

A stoichimetric mixture of evaporating materials for $AgInS_2$ single crystal thin films was prepared from horizontal furnace. To obtain the single crystal thin films. $AgInS_2$mixed crystal was deposited on thorughly etched semi-insulating GaAs(100) substrate by the Hot wall Epitaxy (HWE) system. The source and substrate temperatures were $680^{\circ}C$ and $410^{\circ}C$, respectively. The crystalline structure of the single thin films was investigated by the photoluminescence and double crystal X-ray diffraction(DCXD). The carrier density and mobility of $AgInS_2$ single crystal the films measured from Hall effect by van der Pauw method are $9.35\times 10^{16}/\terxtm{cm}^3$ and $294\terxtm{cm}^2$/V.s at 293 K, respectively. From the optical absorption measurement the temperature dependence of the energy band gap on AgInS$_2$ single crystal thin film was found to be $E_g$(T)= 2.1365eV-($9.89\times 10^{-3}eV/T^2$/(2930+T). After the as-grown $AgInS_2$ single crystal thin films was annealed in $Ag^-S^-$ and In-atmospheres, the origin of point defects of AgInS$_2$ single crystal the films has been investigated by using the photoluminescence(PL) at 10K. The native defects of $V_{Ag},V_s, Ag_{int}$ and $S_{int}$ int/ obtained from PL measurements were classified as a donors or acceptors type. And we concluded that the heat-treatment in the S-atmosphere converted $AgInS_2$ single crystal thin films to an optical p-type. Also, we confirmed that In in $AgInS_2$ /GaAs did not form the native defects because In is $AgInS_2$ single crystal thin films did exist in the form of stable bonds.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.3
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• pp.988-1004
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• 1996

The characteristics of flow and oxygen concentration are numerically studied in Czochralski 8" silicon crystal growing process considering radiative heat transfer. The analysis of net radiative heat flux on all relevant surfaces shows growing crystal affects the heater power. Furthermore, the variation of the radiative heat flux along the crystal surface in the growing direction is confirmed and should be a cause of thermal stress and defect of the crystal. The calculated distributions of temperature and, heat flux along the wall boundaries including melt/crystal interface, free surface and crucible wall indicate that the frequently used assumption of the thermal boundary conditions of insulated crucible bottom and constant temperature at crucible side wall is not suitable to meet the real physical boundary conditions. It is necessary, therefore, to calculate radiative heat transfer simultaneously with the melt flow in order to simulate the real CZ crystal growth. If only natural convection is considered, the oxygen concentration on the melt/crystal interface decreases and becomes uniform by the application of a cusp magnetic filed. The heater power needed also increases with increasing the magnetic field. For the case of counter rotation of the crystal and crucible, the magnetic field suppresses azimutal flow produced by the crucible rotation, which results in the higher oxygen concentration near the interface.

• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.4
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• pp.410-417
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• 2012

Currently domestic thermal and nuclear power plants are comprised of many type's condenser and steam generator tubes to produce the electricity of good quality. There are some methods to inspect these tubes in the event that several defects were discovered in these facilities. Among many non-destructive methods, we used guided wave to inspect the soundness of tubes, because this method is very fast to detect the defect and very simple to install the equipment and also, can inspect up to the long range at a fixed point. Also, this method has a drawback that does not detect a very small size defect. So, we made an effort to overcome this drawback through the experimentation and signal analysis according to the size and shape of the defect through the manufacture of various artificial cracks capable to generate within the small size tube in the study and we anticipate that these detect limits can be overcome along with the development of the signal processing and manufacturing technology of the sensor for the inspection.

• Archives of Craniofacial Surgery
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• v.21 no.5
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• pp.276-282
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• 2020

Background: Orbital fractures are the most common pediatric facial fractures. Treatment is conservative due to the anatomical differences that make children more resilient to severe displacement or orbital volume change than adults. Although rarely, extensive fractures may result in enophthalmos, causing cosmetic problems. We aimed to establish criteria for extensive fractures that may result in enophthalmos. Methods: We retrospectively reviewed the charts of patients aged 0-15 years diagnosed with orbital fractures in our hospital from January 2010 to February 2019. Computed tomography images were used to classify the fractures into linear, trapdoor, and open-door types, and to estimate the defect size. Data on enophthalmos severity (Hertel exophthalmometry results) and fracture pattern and size at the time of injury were obtained from patients who did not undergo surgery during the follow-up and were used to identify the surgical indications for pediatric orbital fractures. Results: A total of 305 pediatric patients with pure orbital fractures were included-257 males (84.3%), 48 females (15.7%); mean age, 12.01±2.99 years. The defect size (p=0.002) and fracture type (p=0.017) were identified as the variables affecting the enophthalmometric difference between the eyes of non-operated patients. In the linear regression analysis, the variable affecting the fracture size was open-door type fracture (p<0.001). Pearson's correlation analysis demonstrated a positive correlation between the enophthalmometric difference and the bony defect size (p=0.003). Using receiver operating characteristic curve analysis, a cutoff value of 1.81 ㎠ was obtained (sensitivity, 0.543; specificity, 0.724; p=0.002). Conclusion: The incidence of enophthalmos in pediatric pure orbital fractures was found to increase with fracture size, with an even higher incidence when open-door type fracture was a cofactor. In clinical settings, pediatric orbital fractures larger than 1.81 ㎠ may be considered as extensive fractures that can result in enophthalmos and consequent cosmetic problems.

• Clinical and Experimental Pediatrics
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• v.50 no.10
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• pp.970-975
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• 2007

Purpose : Accurate measurement of defect size is important in transcatheter closure of atrial septal defect (ASD). We performed this study to analyze the difference between the measured ASD size and balloon occlusive diameter (BOD) by transthoracic (TTE) or transesophageal echocardiography (TEE). Methods : We investigated 78 patients who underwent transcatheter closure of ASD. The defect size and the distance between the surrounding structures were measured by TTE and TEE. The BOD was measured by TEE during cardiac catheterization. Clinical characteristics and echocardiographic data were compared and analyzed. Results : The difference between BOD and diameter by TTE was $4.8{\pm}3.6mm$ on short axis view, $5.4{\pm}3.2mm$ on long axis view. The difference between BOD and diameter by TEE was $3.6{\pm}2.2mm$ on short axis view, $4.2{\pm}3.1mm$ on long axis view. The difference between BOD and the diameter of defects on TTE, TEE had statistically significant positive correlations with the age of the patients, distance between the, defect and posterior atrial septal wall, the distance between the defect and the mitral valve leaflet, and the diameter of defects and the length of the atrial septum on TTE (P<0.05). Conclusion : BOD of ASD can be estimated by the diameter on TTE and TEE. BOD is expected to measure larger, depending on the size of defects, the distance from surrounding structures and the location of defects on echocardiography. Our data offers important information on details of transcatheter ASD closure which can be helpful in predicting suitability and judging the procedural appropriateness during the procedure.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.21 no.3
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• pp.312-316
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• 1999

When the external force was applied to the orbit the most thin area might be displaced. These were usually orbital floor and/or medial wall of orbit. Among these cases some who showed the entrapment of the muscle between the fractured fragments needed the surgical treatment. We had operated 4 cases of the "blow-out" fracture via subciliary approach. The entrapped muscles were freed from fragments and the bony defect was restored with micro-titanium mesh. Mean follow-up periods was 15 months and there were no complication observed.

• Investigative Magnetic Resonance Imaging
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• v.21 no.3
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• pp.183-186
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• 2017

A 7-year-old boy, diagnosed with an arachnoid cyst and subdural effusion on initial MRI, was admitted with left limb weakness and no history of head trauma. A subsequent follow-up MRI showed different stages of hematoma within multilayered enhancing membranes and in the arachnoid cyst, which was separated by the cerebrospinal fluid cleft. Craniotomy and fenestration of the cyst wall and hematoma removal were performed. The patient was diagnosed as a having a hemorrhagic rupture of an arachnoid cyst into the intradural space, probably via some one-way valve-like defect, based on the MRI and surgical findings. The MRI features and possible mechanism of this rare disease are discussed within the literature review.

• Journal of Korea Multimedia Society
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• v.23 no.8
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• pp.903-914
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• 2020

In this paper, we present a novel algorithm to generate a 3D model of patient-specific orbital implant, which is finally produced by the 3D printer. Given CT (computed tomography) scan data of the defective orbital wall or floor, we compose the depth image of the defect site by using the depth buffering, which is a computer graphics technology. From the depth image, we compute the 3D surface which fills the broken part by interpolating the points around the broken part. By thickening the 3D surface, we get the 3D volume mesh of the orbital implant. Our algorithm generates the patient-specific orbital implant whose shape is accurately coincident to the broken part of the orbit. It provides the significant time efficiency for manufacturing the implant with supporting high user convenience.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.18 no.2
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• pp.279-285
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• 1996

The odontogenic keratocyst(OKC) was used of term and described some of clinical, radiological and microscopic features by Philipsen 1956. The microscopic finding of OKC is characterized by the production of keratin, Which sometimes fills the lumen and thinning of epithelium of cyst. The most clinical importance of OKC is its extraordinary recurrence rate owing to the incomplete removal of the cyst wall. The final diagnosis of OKC should be evaluated by histologic findings and follow-up of any case of OKC with annual roentgenograms and clinical evaluations is essential for at least five years after surgery. This article is report of 2 cases of large OKC involved both molar portion and symphysis of mandible with facial asymmetry, severe bone destruction and paresthesia of lower lip on clinically, roentgenographically. By the postoperative findings the patients showed normal regeneration of bone defect area without recurrence signs by panorama films after surgery.