• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.2 s.233
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• pp.253-261
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• 2005

In decades, a substantial body of work on a unified viscoplastic model which considers the mechanism of plastic deformation and creep deformation has developed. The systematic scheme for numerical analysis of unified model is necessary because the dominant failure mechanism is the defect growth and coalescence in materials. In the present study, the unified viscoplastic model for materials with defects suggested by Suquet and Michel was employed for numerical analysis. The constitutive equations are integrated based on the generalized mid-point rule and implemented into a finite element program (ABAQUS) by means of user-defined subroutine (UMAT). To evaluate the validity of the developed UMAT code and the assessment of the adopted viscoplastic model, the results obtained from the UMAT code was compared with the numerical reference solution and experimental data. The unit cell analysis also has been investigated to study the effect of strain rate, temperature, stress triaxiality and initial defect volume fraction on the growth and coalescence of the defect.

• Korean Journal of Crystallography
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• v.14 no.2
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• pp.84-92
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• 2003

The fast pulling is easy to modify the distribution of grown-in defects toward fine size, which can be readily removed by additional treatment. In this experiment, The fast pulled crystals with high pulling late over 1.0 mm/min were grown and their grown-in defect distributions were investigated. In our recent developments in the growth of Cz-Si, it could be found that the cooling rate in a specific temperature range and the uniformity of temperature gradient at solid/liquid interface are more important for the formation of grown-in defect than the pulling rate itself. We analyzed these cooling rates and temperature gradients for the various fast pulled crystals and compared them to the observed formation behavior of the grown-in defects. The effective factor (Ω) for the void defect formation was introduced and it could explain the radial distribution of void defects in the fast-pulled crystals effectively.

• Journal of Distribution Science
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• v.17 no.4
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• pp.51-57
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• 2019

Purpose - This study aims to improve the distribution structure of the OLED market and develop cost-effective optimization techniques. Specifically, it is a study on the optimization of ferric chloride to improve the etch of SUS MASK for OLED. Research design, data, and methodology - Applying the optimal conditions of the experiment, the final confirmation was evaluated for improvement by the Process Capability Index (Cpk). It is possible to derive social performance such as improvement of precision of SUS MASK manufacturing, economic performance such as defect rate, reduction of waste generation and treatment cost, technological achievement such as SUS MASK production technology, improvement of profit structure of technology development and process improvement do. Results - The improvement of the Cpk before the improvement was made was confirmed to be 0.57% with a defect estimate of 25.07% with a failure estimate of 0.57% after the improvement, and 8.84% with a failure estimate of 0.57% level after the improvement. Conclusions - If the conclusions obtained from the specimen experiment are applied to the manufacturing process of SUS MASK, it will be possible to expect excellent cost-effective competitiveness due to the improvement of precision and reduction of defect rate to enhance the OLED market penetration.

• Applied Microscopy
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• v.6 no.1
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• pp.33-38
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• 1976

Formation of crystal defects which may occur during and after the vacuum deposition of silver films on rocksalt substrates were studied by electron microscopy. To obtain defect free films, various evaporation conditions, such as evaporation rate, substrate temperature, substrate treatments and annealing of films were examined. Stacking faults and micro-twins are dominant defects in silver films.

• Journal of Chest Surgery
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• v.27 no.3
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• pp.196-201
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• 1994

Endocardial cushion defect is a rare congenital heart disease. From September 1985, we experienced 20 cases of endocardial cushion defects and postoperative follow up was taken.We reviewed preoperative clinical data, echocardiography, cardiac cath data, operative method & time. After operation, we performed echocardiography and examined mitral valve function & integrity of patch closure sites. Postoperative follow up was taken regularly & follow up period was from 2 month to 91 months. Several postoperative complications were overcome with adequate treatment. There were 3 cases of early death and mortality rate was 15% [3/20].

• Journal of Preventive Medicine and Public Health
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• v.14 no.1
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• pp.13-22
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• 1981

A study was conducted to provide comprehensive information on epidemiological state of crippled schoolchildren in Chungnam area from November 23,1979 to June 19,1980. In this study, two step survey was conducted upon whole primary, middle and high school, and subsequent selected 537 cases in total 3,063 crippled children. The results obstained are as follows; 1. The prevalence rate of orthopedic defect children was 3.7 per 1,000 and dominant male as 6:4. 2. It was relatively higher the school grade and prevalence rate more increased. Prevalence rate was highest in high school as 4.7 per 1,000, middle in middle school as 4.4 per 1,000 and lowest in primary school as 3.1 per 1,000. 3. The most predominant group was $15{\sim}19$ age as 52.9 percent. 4. The most common job of their parent was agriculture as 52.9 percent and next job sales and service. Economic state of Cripple's parent have revealed no particular difference. 5. In a family, the most common incidence rate was first children in both sex and decreased by ordered sibling. 6. Poliomyelitis was the most common cause as 71.5 percent and next cerebral palsy 11.9 percent. 7. The most common affected site was lower extremity (Right: 42.3%, Left: 35.5%) and next upper extremity. Right was more dominant as 55 : 45. 8. Intelligence was decresed in cerebral palsy predominantly than other cause of defect, including poliomyelitis. 9. For the treatment of their condition at onset of illness, crippled children was utilized private clinic and herb medicine, but was changed tendency of treatment as acupucture and moxibustion after diagnosis of cause of defect.

• Journal of KIBIM
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• v.2 no.2
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• pp.27-36
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• 2012

Recently, apartment housing tends to increase 3-4% every year by economic growth and development of construction technology in domestic construction industry. According to this tendency, construction enterprises are providing high-quality and various residential space, and residents also want high-quality apartment housing without any defect. Construction company make efforts to decrease construction defects in order to satisfy all the residents, and to improve company value. However, it is impossible to have no defect in construction because construction works are combination of many different complicated process. Because of the responsibility for the defect, conflicts between construction company and residents have been occurred. This study suggests defects management method that can be used from defect register phase to defect repair phase with a function of smart-device of the high penetration rate. The effectiveness use of the suggested method might save defects maintenance time and improve resident satisfaction about construction quality.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.40
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• pp.11.1-11.5
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• 2018

Background: Squamous cell carcinoma (SCC) is the most commonly occurring malignant tumor in the oral cavity. In South Korea, it occurs most frequently in the mandible, tongue, maxilla, buccal mucosa, other areas of the oral cavity, and lips. Radial forearm free flap (RFFF) is the most widely used reconstruction method for the buccal mucosal defect. The scar of the forearm donor, however, is highly visible and unsightly, and a secondary surgical site is needed when such technique is applied. For these reasons, buccal fat pad (BFP) flap has been commonly used for closing post-surgical excision sites since the recent decades because of its reliability, ease of harvest, and low complication rate. Case presentation: In the case reported herein, BFP flap was used to reconstruct a cheek mucosal defect after excision. The defect was completely covered by the BFP flap, without any complications. Conclusion: Discussed herein is the usefulness of BFP flap for the repair of the cheek mucosal defect. Also, further studies are needed to determine the possibility of using BFP flap when the defect is deep, and the maximum volume that can be harvested considering the changes in volume with age.

• Korean Journal of Crystallography
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• v.4 no.1
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• pp.11-17
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• 1993

Corundum single crystals were grown by the Czochralski technique. Relationships between crystal quality and crystal growth factors such as pulling rate, rotation rate and temperature of the melt were investigated. Optimum pulling and rotation rate for high quality corundum single crystal growth were 4.0mm/hr, 30rpm respectively. Pore was a main defect in corundum crystal and also discussed how to remove this defect by melt temperature control. Growth direction of as grown crystals was identified with(0001). And this direction had largest growth rate. Room temperature absorption spectra were measured and discussed for Cr3+ion doped and non-doped corundum crystals.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.1
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• pp.78-85
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• 1986

This study has been made to investigate Behavior of the fatigue crack propagation for the purpose of taking into consideration the fatigue behavior Which initiate and propagate in tip of defect of the defected specimens, Which Contain the micro-hole or micro-slit. Especially, the specimens have been conducted with high-freguency heat treatment of 850.deg. C, 1050.deg. C to consider strength elevation of defected specimens. The results of this study are as follow; (1) The case of the same in the length of crack, the fatigue crack propagation rate of the micro-slit is always faster than that of micre-hole. But, the first step of the fatigue crack propagation it is not always so. (2) Fatigue crack propagation rate of specimens with micro-slit or micro-hole which have been treated with high-frequency heat treatment satisfy the following formula between the fatigue crack propagation rate and nominal stress; dl/dN .var..sigma.$^{m}$ *l$^{n}$ .