• Applied Microscopy
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• v.42 no.3
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• pp.164-173
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• 2012

The relaxor ferroelectric feature in lead-free perovskite oxides, where the dipoles are randomly oriented and they can be feasibly aligned parallel to the external bias, is attracting lots of attention in the field of piezoelectric materials science, since it is one of candidates to replace the toxic lead-based materials that are still being commercially used. However, the origin of relaxor characteristic and its related atomic structure are still ambiguous. In this study, $Na_{1/2}Bi_{1/2}TiO_3$, chosen as a model relaxor system, was found to exhibit a cationic-disordered atomic structure; and furthermore the nonpolar atomic structure and its related oxygen tilting were ascertained via annular bright field imaging skill. We also found that this cationic disordering gives rise to the local formation of atomic vacancies.

• Journal of Chest Surgery
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• v.18 no.2
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• pp.360-370
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• 1985

A case of complete interruption of aortic arch with aortopulmonary window, patent ductus arteriosus, and aberrantly originated right subclavian artery from proximal descending aorta, in a four year old boy is reported in detail. This is the only reported case in Korea, who has had a successful one-stage total anatomical correction of this combination of defects. Under deep hypothermia and total circulatory arrest, aortic continuity was established using patent ductus arteriosus and anterior wall of pulmonary artery, which was anastomosed obliquely to anteromedial side of ascending aorta. Aortopulmonary window was closed using Impra patch via pulmonary arteriotomy. Then pulmonary arteriotomy was reconstructed primarily except at the junction of right pulmonary artery and main pulmonary artery, where a small piece of pericardium was used to close the defect to prevent kinking and narrowing of right pulmonary artery. Postoperative cardiac catheterization demonstrated a good reconstruction.

• Nuclear Engineering and Technology
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• v.38 no.5
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• pp.405-410
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• 2006

Microstructural features and their related mechanical property changes in the 309L cladding and the heat affected zone (HAZ) of SA508 cl.3 steel were investigated through the use of TEM, tensile and small punch (SP) tests. The specimens were irradiated at 563 K up to the neutron fluences of $5.79{\times}10^{19}n/cm^2$ (>1MeV). The microstructure of the clad was mainly composed of a fcc ${\gamma}-phase$, a low percentage of bcc ${\delta}-ferrite$, and a brittle ${\sigma}-phase$. Along the weld fusion line there formed a heavy carbide precipitation with a width of $20{\sim}40{\mu}m$, showing preferential cracking during plastic deformation. The yield stress and ductile-to-brittle transition temperature (DBTT) of the irradiated clads increased. The origin of the hardening and the shift of the DBTT are discussed in terms of the irradiation-produced defect clusters of a fine size and brittle ${\sigma}-phase$.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.236-236
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• 2006

Time-resolved photoluminescence spectroscopy measurements of oligofluorenes with various side chains were studied. With extremely pure oligofluorenes, two kinds of red-shifted green emission were observed which have different origins; aggregate formation and on-chain chemical defect. The green emission around 490 nm was largely dependent upon the intermolecular interaction of oliglfuorene molecules. Moreover, by using oligofluorene with high-order liquid crystalline phase, we observed that the green emission was strongly dependent upon the molecular packing in solid films.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.445-448
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• 2006

Bias stress effect in pentacene organic thin-flim transistors with cross-linked PVA gate dielectric is analyzed. For negative gate bias stress, positive threshold voltage shift is observed. The injected charges from the gate electrode to the defect states of gate dielectric are regarded as the main origin of $V_T$ shift. The reduced bias stress effect using $SiO_2$ blocking layer confirms the assumed mechanism. It is also demonstrated that the inverter with $SiO_2$ blocking layer shows the negligible hysteresis owing to the reduced bias stress effect.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.11
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• pp.2742-2748
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• 2000

In this study, the quantitative evaluation was performed by examination for gatigue crack origin in two prepared ductile irons specimens which have different microstructures using rotary bending fatigue tester, Series A has mixed microstructure. ferrite plus pearlite, and series B has bainitic microstructure. Obtained main results are as follows. The scatterings of fatigue strength were observed on σ(sub)α-Ν diagram of both specimen series, and it is observed that scatterings of series A were more serious. It is reasonable to evaluate the size of mesocrack range by means of √A(원문참조), where A means the area of mesocrack range including globular graphite nodule. As a result of reconsideration for the fatigue data by introduction of K(sub)α-Ν diagram, the scattrings of fatigue life were, remarkably. reduced. Therefore, it is more reasonable to evaluate of mesocrack range on fatigue life by parameter K(sub)α rather than σ(sub)α.

• Journal of Photoscience
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• v.6 no.4
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• pp.183-186
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• 1999

We have been prepared the porous silicon carbide (PSC) by electrochemical etching of silicon carbide single crystals. Samples of PSC have been studied by the methods of scanning electron microscope (SEM) and photoluminescence (PL). Two PL bands attributed to the blue and green light emission were observed in this study. According to the anodization conditions, the main source of emission in the oxidized layers of PSC lies in the different surface defect centers which consist of different geometrical structures due to the polytypes. It means that origin of these PL bands may be existed in different size pores simultaneously. The present results indicate that the high energy band comes from the top porous layers while the low energy band comes from the lower porous layers.

• Journal of Korean Dental Science
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• v.16 no.2
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• pp.211-217
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• 2023

Fibrous dysplasia (FD) accompanying osteomyelitis (OM) has been reported to result in recurrent, refractory pain and swelling. Although radical resection of the lesions has been suggested, effective surgical treatment strategies have not yet been established due to the limited number of studies on this pathological condition. In this report, we present the conservative surgical management of FD accompanying OM in two patients who exhibited recurrent signs and symptoms. The present report suggests that OM occurring in patients with FD can be successfully managed with conservative surgical treatment and following removal of the odontogenic origin although bone defect in which inflammatory fibro-osseous lesions is removed through decompression surgery may exhibit regeneration of dysplastic bone. In addition, for the prevention of OM in patients with FD, careful clinical examination and thorough management of dental-related pathologies are necessary with regular follow-up examinations to screen for the possibility of malignant changes.

• Archives of Plastic Surgery
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• v.38 no.5
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• pp.695-698
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• 2011

Purpose: Since spinal tuberculosis is increasing in prevalence, it appears that a repair of spinal soft tissue defect as a complication of spinal tuberculosis can be a meaningful work. We report this convenient and practical reconstructive surgery which use bilateral latissimus dorsi musculocutaneous advancement flap. Methods: Before the operation, $13{\times}9.5$ cm sized skin and soft tissue defect was located on the dorsal part of a patient from T11 to L3. And dura was exposed on L2. Under the general endotrachel anesthesia, the patient was placed in prone position. After massive saline irrigation, dissection of the bilateral latissimus dorsi musculocutaneous flaps was begun just upper to the paraspinous muscles (at T11 level) by seperating the paraspinous muscles from overlying latissimus dorsi muscles. The plane between the paraspinous muscles fascia and the posterior edge of the latissimus dorsi muscle was ill-defined in the area of deformity, but it could be identified to find attachment of thoracolumbar fascia. The seperation between latissimus dorsi and external oblique muscle was identified, and submuscular plane of dissection was developed between the two muscles. The detachment from thoracolumbar fascia was done. These dissections was facilitated to advance the flap. The posterior perforating vasculature of the latissimus dorsi muscle was divided when encountered approximately 6 cm lateral to midline. Seperating the origin of the latissimus dorsi muscle from rib was done. The dissection was continued on the deep surface of the latissimus dorsi muscle until bilateral latissimus dorsi musculocutaneous flaps were enough to advance for closure. Once this dissection was completely bilateraly, the bipedicled erector spinae muscle was advanced to the midline and was repaired 3-0 nylon to cover the exposed vertebrae. And two musculocutaneous units were advanced to the midline for closure. Three 400 cc hemovacs were inserted beneath bilateral latissimus dorsi musculocutaneous flaps and above exposed vertebra. The flap was sutured with 3-0 & 4-0 nylon & 4-0 vicryl. Results: The patient was kept in prone and lateral position. Suture site was stitched out on POD14 without wound dehiscence. According to observative findings, suture site was stable on POD55 without wound problem. Conclusion: Bilateral latissimus dorsi musculocutaneous advancement flap was one of the useful methods in repairing of large spinal soft tissue defect resulting from spinal tuberculosis.

• Journal of the Korean Vacuum Society
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• v.7 no.2
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• pp.150-154
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• 1998

Photoluminescence(PL), XRD, TEM results $5\times1016/\textrm{cm}^2, 1\times10^{17}/\textrm{cm}^2, 3\times10^{17}/\textrm{cm}^2$ Si-implanted $SiO_2$ films on crystalline silicon are reported. At low dose implantation and low annealing temperature, visible PL are observed. The PL spectrum has 7400$\AA$ and 8360$\AA$ peaks. As annealing time increased, the PL intensity are increased and peak positions are changed. The PL spectrum are not observed at high dose implantation and high annealing temperature. For the samples of low dose and high annealing temperature, visible PL are observed at short annealing time (30 minutes) and disappear for more than 1 hour annealing. From XRD and TEM results, silicon cluster are related to nonradiative defects. It is concluded that the origin of visible PL in Si implanted SiO2 films are not nanocrystal but two kinds of radiative defects. The Si-O-O bonding related defects (O rich defects) and Si-Si-O bonding related defects (Si rich defects) are related to the PL spectrum and depend on concentraion of Si implantation, annealing temperature and time.