• Korean Journal of Materials Research
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• v.8 no.10
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• pp.931-937
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• 1998

The electrical conductivity of undoped mtile was measured in the oxygen partial pressure range of $1~10{-23}$atm and temperature range of $700~1300^{\circ}C$ to investigate the defect types and the electrical properties. The data(logu/logPoz) were divided into the five regions. Therefore the five dominant defect types such as $Ti_nO_{2n-1}$, Ti, Vo, Vo due to impurity, and n-p transition or p-type conduction with the Poz and the temperature were proposed. The formation enthalpies calculated from these experimental results were found to be 10.2eV for Ti, and 4. 92eV for Vo in intrinsic range.

• Korean Journal of Crystallography
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• v.11 no.3
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• pp.176-181
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• 2000

Computer-based atomistic simulation methods are applied to address quantitatively the crystal defect chemistry of strontium hexaaluminate, SrAl/sub 12/O/sub 19/. Our calculations show that oxygen Frenkel disorder is the dominant intrinsic defect mode to be expected in the multi-component oxide, though Schottky disorder may also exist. When La and Mg enter into SrAl/sub 12/O/sub 19/. Mg prefers to occupy Al(3)4f tetrahedral sites in the magnetoplumbite structure. Our calculations also indicate that O/sub Sr/ defect is improbable in the structure.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1036-1039
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• 2009

We have developed an automated circuit defect repair method. We focused on the resist patterns on the circuit material layer of TFT substrates before the etching process. In this paper, we report on the repair method that utilizes the syringe system and the stability of the open defect repair process.

• Journal of Ocean Engineering and Technology
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• v.3 no.2
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• pp.601-601
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• 1989

The behavior of fatigue was studied by using low carbon steel bar with microhole(artificial small defect) under the condition of rotary bending stress which is made artificially at smooth surface and round notch root. The results obtained can be summerized; The behavior of non-propagating cracks which are produced at both tips of small defect occurred to dissymmetry, and it is found to be double size of small defect. For the range of l>lc, threshold stress intensity is constant. However, for the range of l

• Journal of Periodontal and Implant Science
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• v.46 no.4
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• pp.244-253
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• 2016

Purpose: The aim of this study was to characterize the healing in the grafted calvarial defects of rats after adjunctive hyperbaric oxygen therapy. Methods: Twenty-eight male Sprague-Dawley rats (body weight, 250-300 g) were randomly divided into two treatment groups: with hyperbaric oxygen therapy (HBO; n=14) and without HBO (NHBO; n=14). Each group was further subdivided according to the bone substitute applied: biphasic calcium phosphate (BCP; n=7) and surface-modified BCP (mBCP; n=7). The mBCP comprised BCP coated with Escherichia-coli-derived recombinant human bone morphogenetic protein-2 (ErhBMP-2) and epigallocatechin-3-gallate (EGCG). Two symmetrical circular defects (6-mm diameter) were created in the right and left parietal bones of each animal. One defect was assigned as a control defect and received no bone substitute, while the other defect was filled with either BCP or mBCP. The animals were allowed to heal for 4 weeks, during which those in the HBO group underwent 5 sessions of HBO. At 4 weeks, the animals were sacrificed, and the defects were harvested for histologic and histomorphometric analysis. Results: Well-maintained space was found in the grafted groups. Woven bone connected to and away from the defect margin was formed. More angiogenesis was found with HBO and EGCG/BMP-2 (P<0.05). None of the defects achieved complete defect closure. Increased new bone formation with HBO or EGCG/BMP-2 was evident in histologic evaluation, but it did not reach statistical significance in histometric analysis. A synergic effect between HBO and EGCG/BMP-2 was not found. Conclusions: Within the limitations of this study, the present findings indicate that adjunctive HBO and EGCG/BMP-2 could be beneficial for new bone formation in rat calvarial defects.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.121-121
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• 1999

Gallium nitride (GaN) semiconductor is intensively under investigation for commercialization of short wavelength light emitting devices and laser diodes. One of serious obstacles to overcome is to reduce the defect density in GaN film grown by various techniques such as MOCVD, HVPE, etc. Many research groups including SAIT are trying to improve the defect density to 106-107/cm2 from the level of 108-1010/cm2. We have investigated epitaxial growth behaviour of GaN thin and thick films under hidride vapour phase epitaxy (HVPE) condition. In this report, we present the microstructural and crystallographical characteristics of the GaN films grown on sapphire (0001) substrate which were studied by both conventional and high-resolution transmission electron microscopy (TEM). Also we present some microscopic analysis results obtained from GaN films grown by ELO(dpitzsial lateral overgrowth)-HVPE and from GaN quantum well structures grown by MOCVD. Another serious problem in growing GaN thick film by HVPE is internal micro-cracks. We also comment the origin of the micro-crack.

• Journal of the Korean Ceramic Society
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• v.44 no.4 s.299
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• pp.202-207
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• 2007

High-Quality 1-Dimensional InN single crystalline have been grown by Halide Vapor-Phase Epitaxy on the Au catalyst coated Si substrate using the vapor-liquid-solid growth mechanism. We have been grown 1-dimension InN nanowires having controlled the growth conditions for substrate temperature and gases flow rate. The grown InN nanowire of characteristics for morphologies, crystal structure, and element analysis were carried out by SEM, HR-TEM, and EDS respectively. And the defects of InN crystalline were analyzed by indexing of selective area diffraction pattern with attached HR-TEM. We have successfully obtained the defect-free 1-dimensional InN single crystalline nanowire at the atmosphere pressure.

• Journal of the Korean institute of surface engineering
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• v.36 no.2
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• pp.135-140
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• 2003

The difference in lattice parameter and thermal expansion coefficient between GaN and Si which results in many defects into the grown GaN is larger than that between GaN and sapphire. In order to obtain high quality GaN films on Si substrate, it is essential to understand growth characteristics of GaN. In this study, GaN layers were grown on Si(111) substrates by MOCVD at three different GaN growth temperatures ($900^{\circ}C$, $1,000^{\circ}C$ and $1,100^{\circ}C$), using AlN and LT-GaN buffer layers. Using TEM, we carried out the comparative investigation of growth characteristics of GaN by characterizing lattice coherency, crystallinity, orientation relationship and defects formed (transition region, stacking fault, dislocation, etc). The localized region with high defect density was formed due to the lattice mismatch between AlN buffer layer and GaN. As the growth temperature of GaN increases, the defect density and surface roughness of GaN are decreased. In the case of GaN grown at $1,100^{\circ}$, growth thickness is decreased, and columns with out-plane misorientation are formed.

• Archives of Plastic Surgery
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• v.39 no.4
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• pp.323-328
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• 2012

Background Among the various methods for correcting nasal deformity, the composite graft is suitable for the inner and outer reconstruction of the nose in a single stage. In this article, we present our technique for reconstructing the ala and columella using the auricular chondrocutaneous composite graft. Methods From 2004 to 2011, 15 cases of alar and 2 cases of columellar reconstruction employing the chondrocutaneous composite graft were studied, all followed up for 3 to 24 months (average, 13.5 months). All of the patients were reviewed retrospectively for the demographics, graft size, selection of the donor site and outcomes including morbidity and complications. Results The reasons for the deformity were burn scar (n=7), traumatic scar (n=4), smallpox scar (n=4), basal cell carcinoma defect (n=1), and scar contracture (n=1) from implant induced infection. In 5 cases of nostril stricture and 6 cases of alar defect and notching, composite grafts from the helix were used ($8.9{\times}12.5$ mm). In 4 cases of retracted ala, grafts from the posterior surface of the concha were matched ($5{\times}15$ mm). For the reconstruction of the columella, we harvested the graft from the posterior scapha ($9{\times}13.5$ mm). Except one case with partial necrosis and delayed healing due to smoking, the grafts were successful in all of the cases and there was no deformity of the donor site. Conclusions An alar and columellar defect can be reconstructed successfully with a relatively large composite graft without donor site morbidity. The selection of the donor site should be individualized according to the 3-dimensional configuration of the defect.

• Journal of the Korean Ceramic Society
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• v.17 no.1
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• pp.5-7
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• 1980

The electrical conductivity of polycrystalline $Gd_2O_3$ has been measured over the temperature range of 650 to 100$0^{\circ}C$ under the oxygen pressure range of $10^{-6}$ to 102 torr. The oxygen pressure dependence of electrical conductivity, $\sigma$ PO211/n is characterized by n value of about 5.3. The defect structure and the type of the oxide are controlled by triply ionized metal vacancies and holes.