• Title/Summary/Keyword: Defects

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FPGA based System for Pinhole Detection in Cold Rolled Steel (FPGA 기반의 냉연강판 핀홀 검출 시스템)

  • Ha, Sung-Kil;Lee, Jung Eun;Moon, Woo Sung;Baek, Kwang Ryul
    • Journal of Institute of Control, Robotics and Systems
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    • v.21 no.8
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    • pp.742-747
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    • 2015
  • The quality of steel plate products is determined by the number of defects and the process problems are estimated by shapes of defects. Therefore pinholes defects of cold rolled steel have to be controlled. In order to improve productivity and quality of products, within each production process, the product is inspected by an adequate inspection system individually in the lines of steelworks. Among a number of inspection systems, we focus on the pinholes detection system. In this paper, we propose an embedded system using FPGA which can detect pinholes defects. The proposed system is smaller and more flexible than a traditional system based on expensive frame grabbers and PC. In order to detect consecutive defects, FPGAs acquire two dimensional image and process the image in real time by using correlation of lines. The proposed pinholes detection algorithm decreases arithmetic operations of image processing and also we designed the hardware to shorten the data path between logics due to decreasing propagation delay. The experimental results show that the proposed embedded system detects the reliable number of pinholes in real time.

THE USE OF A VARIETY OF INTRAORAL FLAPS IN RECONSTRUCTION OF INTRAORAL SOFT TISSUE DEFECTS (구강내 연조직 결손 재건을 위한 다양한 구내피판의 이용)

  • Kim, Young-Kyun;Yeo, Hwan-Ho
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.19 no.3
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    • pp.243-249
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    • 1997
  • The purpose of this study is to describe the clinical availability of a variety of intraoral local flaps in reconstruction of oral soft tissue defects, Forty patients with oral soft tissue defects were treated by tongue, buccinator, palatal, labial, facial artery musculomucosal, buccal fat pad, and masseter muscle crossover flap. Total 43 intraoral flaps were used to reconstruct a variety of intraoral soft tissue defects, such as oronasal fistula, oroantral fistula, traumatic deformities and other. The age of patients ranged from 7 to 72 years, with mean age of 39.6 years. Follow up period ranged from 2 to 66 months, mean follow up period of 21.6 months. There were 9 complications, of which four were partial necrosis, three infections, one total necrosis, and 1 speech problem. Except for total necrosis, most of the recipient sited healed uneventually without severe morbidity. We consider that a variety of intraoral local flaps can be available for reconstruction of small of moderate large intraoral soft tissue defects.

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Reconstruction of the Three-Dimensional Mandibulofacial Defects Using a Single Cutaneous Perforator-Based Fibula Osteocutaneous Flap

  • Kang, In Sook;Ko, Jun Gul;Choi, Ji Seon;Lim, Jin Soo;Kim, Min Cheol
    • Archives of Craniofacial Surgery
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    • v.18 no.3
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    • pp.214-217
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    • 2017
  • The reconstruction of the mandibulofacial defects is a difficult task when there are full-thickness cheek defects involving mandible, inner mucosa and outer skin. There are several reconstructive options for the coverage of large defects, but most of the methods are complicated, and time- and effort-consuming. We hereby present a case of fibula osteocutaneous flap based on a single peroneal artery perforator in the reconstruction of a three-dimensional mandibulofacial defects.

CERVICAL ISLAND FLAP FOR INTRAORAL REPAIR (경부도상 피판을 이용한 구강내 결손부의 재건)

  • Kim, Jong-Ryoul;Seo, Jong-Cheon;Shin, Sang-Hoon;Lee, Seong-Geun;Yang, Dong-Kyu
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.17 no.3
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    • pp.209-213
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    • 1995
  • Various cutaneous as well as myocutaneous flaps have been designed for the reconstruction of tissue defects caused by the excision of oral cancer. Among these flaps, cervical island skin flap have been introduced by Farr et al and more have developed by Tashiro et al. This flap has many advantages. The flap minimizes donor size by use of cervical operation wound, flap size available is adequate for most oral defects and the procedure is relatively simple and time saving. However, this flap is not applicable in patients where there are large tissue defects and metastasis is suspected. We used this flap for it's rapid, simple, and effective, primary closure of oral defects after cancer ablation and we have found this flap very useful for the reconstruction of relatively small oral defects.

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Characterization of the grown - in defects in the large diameter silicon crystal grown by Czochralski method (대구경 규소 Czochralski 단결정 속의 결정 결함 규명)

  • 이보영;김영관
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.6 no.1
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    • pp.11-18
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    • 1996
  • Grown-in defects like OISF and FPD in the large diameter(> 8 inch)of silicon crystal are characterized. It was revealed that the presence of the ring-patterned OISF would deterorate the minority life time of the silicon crystal. Through the cooling experiment from the $1250^{\circ}C$, the nucleation of the OISF was confirmed to follow the homogeneous nucleation and growth process. In addition to OISF nucleus, crystal originated particle, which was known to be closely related with FPD (Flow Pattern Defects), was found to depend on the pulling rate of the crystal. Combination of the lower rate of the pulling and the faster cooling near the $950^{\circ}C$ is proposed to be effective method in reducing the generation of these grown-in defects.

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A Design and Experiment of Pressure and Shape Adaptive Mechanism for Detection of Defects in Wind Power Blade (풍력 발전용 블레이드 접합부의 결함 검출을 위한 일정가압 메커니즘 설계 및 실험)

  • Lim, Sun;Lim, Seung Hwan;Jeong, Ye Chan;Chi, Su Chung;Nam, Mun Ho
    • Journal of Applied Reliability
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    • v.17 no.3
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    • pp.224-235
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    • 2017
  • Purpose: Reliability is the most important factor to detect defects as wind turbines are deployed in large blades. The methods of detecting defects are various, such as non-destructive inspection and thermal imaging inspection. We propose the phased array ultrasonic testing method of non-destructive testing. Methods: We propose the active pressure mechanism for wind power blade. The phase array ultrasonic inspection method is used for fault detection inner blade surface. Controlled pressure of mechanism with respect to z-axis is important for guarantee the result of phase array ultrasonic inspection. The model based control and proposed mechanism are utilized for overall system stability and effectiveness of system. Result: The result of proposed pressure mechanism B is more stable than A. Convergence speed is also faster than A. Conclusion: We confirmed the performance of the proposed constant pressure mechanism through experiments. Non-destructive testing was applied to the specimen to confirm the reliability of detecting defects.

Two kinds of defects existing on Si(5 5 12)-$2{\times}1$

  • Duvjir, Ganbat;Kim, Hi-Dong;Duvjir, Otgonbayar;Seo, Jae-M.
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.02a
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    • pp.364-364
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    • 2010
  • Defects existing on the clean Si(5 5 12)-$2{\times}1$, composed of one-dimensional(1-D) structures such as honeycomb (H) chain, $\pi$-bonded ($\pi$) chains, dimer-adatom (D-A) row, and tetramer (T) row, have been investigated by scanning tunneling microscopy (STM). It is found that the defects can be classified to two categories: One is originated from phase boundaries in D-A and T rows having $2{\times}$ periodicities, by which buckling directions are reversed, and the other is caused by missing atoms on $\pi$ chains, D-A rows, and T rows. All these defects are symmetric with respect to the [6 6 $\bar{5}$] direction, which is due to one-dimensional symmetry along the [1 $\bar{1}$ 0] direction. Especially it is worth noticing that on H chains none of such defects exist, which implies that the H chain is energetically the most stable among 1-D structures existing on Si(5 5 12)-$2{\times}1$.

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The Combined Scapular and Latissimus Dorsi Free Flap (견갑피판과 광배근피판의 이중유리피판이식술)

  • Chung, Duke-Whan;Han, Chung-Soo;Kwon, Young-Ho
    • Archives of Reconstructive Microsurgery
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    • v.7 no.1
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    • pp.41-46
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    • 1998
  • Microvascular free tissue transfer technique is widely accepted for reconstruction of extensive soft tissue defects on the extremities. The system of flap based on the subscapular artery and vein provides the widest ways of composite free flaps. The possible flaps that can be harvested based on this single vascular pedicle include the scapular and parascapular skin flaps, the serratus anterior and latissimus dorsi muscular flaps, the lateral scapular bone flap, the latissimus dorsi-rib flap, and the serratus anterior-rib flap. This combined flap is available to mutiple tissue defects or complex defects because it can incorporated with skin, muscle and bone flaps. A strikig advantage is the independent vascular pedicles of each components, which allow freedom in orientation of each components. So, it can be freely applied to any forms of three demensional defects on the upper and lower extremities. The combination of scapular cutaneous flap and latissimus dorsi musculocutaneous flap can be resurfaced for massive cutaneous defects on the extremities. We report the use of the combined scapular and latissimus dorsi free flap in seven patients to reconstruct massive deefcts on the extremities. There was no flap failure and little complications and disadvantages. The anatomy of this flap is reviewed and the indication and advantages are discussed.

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Dual Perforator Flap for Reconstruction of Large Sacral Defects: Superior Gluteal Artery Perforator Super-Flap with Parasacral Perforator

  • Tae, Sang Pil;Lim, Seong Yoon;Song, Jin Kyung;Joo, Hong Sil
    • Archives of Reconstructive Microsurgery
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    • v.26 no.1
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    • pp.14-17
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    • 2017
  • The superior gluteal artery perforator flap technique has increasingly been used for soft tissue defects in the sacral area following its introduction nearly 25 years ago. Advantages in covering sacral defects include muscle sparing, versatility in design, and low donor side morbidity. The bilateral superior gluteal artery perforator flap procedure is planned in cases of large sacral defects that cannot be covered with the unilateral superior gluteal artery perforator flap. Here, we report two cases of large sacral defects in which patient factors of poor general health, such as old age, pneumonia, and previous operation scar, led to use of a large unilateral superior gluteal artery perforator super-flap with parasacral perforator. The approach was utilized to reduce the operation time and prevent unpredictable flap failure due to the large flap size. Even though the parasacral perforator was included, the versatility of the large superior gluteal artery perforator flap was preserved because sufficient perforator length was acquired after adequate dissection.

Visualization and classification of hidden defects in triplex composites used in LNG carriers by active thermography

  • Hwang, Soonkyu;Jeon, Ikgeun;Han, Gayoung;Sohn, Hoon;Yun, Wonjun
    • Smart Structures and Systems
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    • v.24 no.6
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    • pp.803-812
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    • 2019
  • Triplex composite is an epoxy-bonded joint structure, which constitutes the secondary barrier in a liquefied natural gas (LNG) carrier. Defects in the triplex composite weaken its shear strength and may cause leakage of the LNG, thus compromising the structural integrity of the LNG carrier. This paper proposes an autonomous triplex composite inspection (ATCI) system for visualizing and classifying hidden defects in the triplex composite installed inside an LNG carrier. First, heat energy is generated on the surface of the triplex composite using halogen lamps, and the corresponding heat response is measured by an infrared (IR) camera. Next, the region of interest (ROI) is traced and noise components are removed to minimize false indications of defects. After a defect is identified, it is classified as internal void or uncured adhesive and its size and shape are quantified and visualized, respectively. The proposed ATCI system allows the fully automated and contactless detection, classification, and quantification of hidden defects inside the triplex composite. The effectiveness of the proposed ATCI system is validated using the data obtained from actual triplex composite installed in an LNG carrier membrane system.