• 한국결정성장학회지
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• 제25권1호
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• pp.13-19
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• 2015

Among the various possible factors affecting the Minority Carrier Life Time (MCLT) of the mc-Si crystal, dislocations formed during the cooling period after solidification were found to be a major element. It was confirmed that other defects such as grain boundary or twin boundary were not determinative defects affecting the MCLT because most of these defects seemed to be formed during the solidification period. With a measurement of total thickness variation (TTV) and bow of the silicon wafers, it was found that residual stress remaining in the mc-Si crystal might be another major factor affecting the MCLT. Thus, it is expected that better quality of mc-Si can be grown when the cooling process right after solidification is carried out as slow as possible.

• 전기전자학회논문지
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• 제18권2호
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• pp.234-239
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• 2014

This paper proposes a new automatic detection method to inspect mura defects on display film surface using morphological image processing and labeling. This automatic detection method for mura defects on display films comprises 3 phases of preprocessing with morphological image processing, Gabor filtering, and labeling. Since distorted results could be obtained with the presence of non-uniform illumination, preprocessing step reduces illumination components using morphological image processing. In Gabor filtering, mura images are created with binary coded mura components using Gabor filters. Subsequently, labeling is a final phase of finding the mura defect area using the difference between large mura defects and values in the periphery. To evaluate the accuracy of the proposed detection method, detection rate was assessed by applying the method in 200 display film samples. As a result, the detection rate was high at about 95.5%. Moreover, the study was able to acquire reliable results using the Semu index for luminance mura in image quality inspection.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.831-833
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• 2000

In this paper, a numerical analysis algorithm of eddy current testing(ECT) for heat exchanger tube with axi-symmetric defects using finite element method(FEM) is presented. In the ECT FEM analysis, we used trianglular and rectangular elements for exact signal of ECT for variable shape of defects. This paper presents a systematic and efficient numerical analysis algorithm for ECT. We employ the LU decomposition and Cholesky method for solving the system matrix. This numerical analysis algorithm is effectively applied to heat exchanger tube with defects.

• 한국기계가공학회지
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• 제7권1호
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• pp.9-16
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• 2008

It is important not only to reduce the casting defects of piston but also to improvement in the mechanical properties(hardness) of piston for the air compressor. The blow hole is typical casting defects in the conventional cast of aluminium alloy(AC8A-T6) piston. Because of the heat treatment method, mechanical properties of the aluminium alloy for piston was decided on the heat treatment method and cycle. Therefore, we tested on the development of mechanical properties and on the casting defects of piston for the air compressor in accordance with the heat treatment and casting condition. After the heat treatment and casting was carried out as several times, and was compared with the imported piston. As a result of several investigations; microstructure, hardness and casting defects of piston was changed under the influence of the heat treatment and casting method. When the cooling rate was controlled and the uni-cast method used, it bas the same mechanical properties and microstructure.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.164-169
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• 2002

Recently, LCD(Liquid Crystal Display) is the display product widely used on various fields of industry. This is generally composed of many parts. Among many parts, polarizer film control the intensity of the transmitted light according to the degree of rotation of the polarizer axis. Therefore, this film must be free from defects. But it contains many defects such as the defects caused by dust or different thing, adhesive badness, scratch. Presently, the inspection of these defects is depending on the sight of operator. In this paper, we propose the vision system composed of telecentric lens and optical mirror. This system use the coaxial illumination and the light is specularly reflected on the optical mirror. And we develop the image processing algorithm using the threshold and morphological technique.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.1097-1102
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• 2005

Non-Destructive Testing (NDT) is test method which finds the mechanical or natural or artificial defects of the interior or exterior of those without destructing materials and welded products. NDT is a means to assess the perfection of a component or system perfection. NOT images defects using scattered light, sound, electric current, magnetic fields and X-ray. Each NDT method has merits and demerits in the detecting ability of defects according to evaluated subjects. Defects can affect the serviceability of the material or structure, so NDT is important in guaranteeing safe operation as well as in quality control. In this review, we considered the methods of NDT applied to current railway vehicle manufacturing.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제18권1호
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• pp.164-174
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• 1996

In order to develop the allogeneic bone implants instead of autogenous bone grafts for maxillofacial reconstruction, undemineralized freeze-dried human bone was processed. The freeze-dried human bone was implanted into the cranial and mandibular defects of the rabbits. The implants were evaluated clinically, roentgenographically and histomophometrically. And immunohistochemical evaluation of the implants was performed on the rat. The results were as follows : 1. When compared with control defects of $0.8{\times}0.8\;cm$, the implants on the rabbit defects displayed complete osseous bridging clinically and roentgenographically. Histomophometrically a minimal inflammatory cell infiltrate was present but the defects healed well clinically. 2. When compared with control grafts, the freeze-dried implants on the rat muscle displayed decreased antigenicity by immunohistochemical evaluation, due to freeze-drying process. 3. Undemineralized freeze-dried human bone in this study can be preserved as a bank bone in this study and seems to be applicable for clinical allogeneic bone grafts.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제39권
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• pp.5.1-5.9
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• 2017

Many congenital and acquired defects occur in the maxillofacial area. The buccal fat pad flap (BFP) is a simple and reliable flap for the treatment of many of these defects because of its rich blood supply and location, which is close to the location of various intraoral defects. In this article, we have reviewed BFP and the associated anatomical background, surgical techniques, and clinical applications. The surgical procedure is simple and has shown a high success rate in various clinical applications (approximately 90%), including the closure of oroantral fistula, correction of congenital defect, treatment of jaw bone necrosis, and reconstruction of tumor defects. The control of etiologic factors, size of defect, anatomical location of defect, and general condition of patient could influence the prognosis after grafting. In conclusion, BFP is a reliable flap that can be applied to various clinical situations.

• 한국결정성장학회지
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• 제10권6호
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• pp.373-377
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• 2000

승화 성장법으로 성장된 6H-SiC 단결정에 대하여 etching을 행하여 형성된 etch pit의 형상과 결함과의 관계에 대하여 고찰하였다. (0001) 기저면에서는 육각형의 전형적인 etch pit이 형성되었다. micropipe에 의해서도 유사한 형태의 pit이 형성되었으며, 면결함에 형성된 etch pits을 통하여 SiC 결정의 내부에 형성된 planar defects도 성장 결정과 동일한 구조를 가지면서 형성됨을 알 수 있었다.

• Journal of Periodontal and Implant Science
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• 제27권3호
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• pp.525-532
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• 1997

The purpose of this study was to evaluate the extent and predictability of periodontal regeneration with barrier membranes in deep infrabony defects. 25 patients(40% smokers) were included in this study. Fourty-one deep infrabony defects treated with membranes(PPD>6mm) were evaluated 1 year postoperatively following a plaque control regimen. Probing pocket depth(PPD), gingival recession(REC), and probing attachment level(PAL) were evaluated at baseline and postoperative 1 year. Plaque score at baseline was 16.2 and plaque score at 1 year was 9.9 A PAL gain of $4.1{\pm}2.5mm$ along with a PPD reduction of $5.0{\pm}2.3mm$ were observed. A PAL gain of $4.1{\pm}2.5mm$ was observed at the smoking group and a PAL gain of $4.0{\pm}2.5mm$ was observed at the non-smoking sroup. It was concluded that periodontal regeneration with membrane represented the predictable and effective treatment modality in the deep infrabony defects.