• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.133-138
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• 2005

Automotive pulleys play a key role in driving the cooling pump, oil pump, air-conditioner and so on by using an engine power. Researches on design processes and technologies of the pulleys can be found in many literatures. On the other hand, the areas related to manufacturing processes of the pulleys have been treated negligently. Vast data extracted from various information systems are transformed, integrated, and summarized to become a special database for helping users make a decision. The database, namely the data warehouse has been popularly used in the marketing and customer management of enterprises and recently applied to improve the design and manufacturing processes. In this study the manufacturing process of pulleys were analyzed through the intensive investigation of shop-floors and the interviews with workers and managers. The defects generated during a manufacturing process were categorized in a few types and the causes of defects examined for extracting the dominant parameters in the setup process for producing pulleys. As the first step to construct the data warehouse for the manufacturing processes of pulleys, authors proposed its architecture focused on the reduction of defect rate during the setup process.

• Archives of Reconstructive Microsurgery
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• 제6권1호
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• pp.56-62
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• 1997

Latissimus dorsi(LD) muscle is the largest transplantable block of vascularized tissue. Since LD free flap was introduced in 1970's, this flap has been widely used for the reconstruction of large soft tissue defect of the limb. From 1981 to 1996, we had experienced 37 cases of LD free flap. Serratus anterior muscle was combined with LD in three of them whose defects were very large. The average age of the patients was 31 years(range : 4-74 years), and thirty one patients were male. Trauma was cause of the defect in every case. For the recipient sites, the foot and ankle was the most common(22 cases); and the knee and lower leg(11 cases), the elbow and forearm(2 cases), the hand(2 cases) were the next. The duration of follow-up was averaged as 16 months(range: 6 months-12 years). Thirty one cases(84%) out of 37 were successful transplantations. In one case the failure of the flap was due to heart attack and subsequent death of the patient. One failure was caused by sudden violent seizure of the patient who had organic brain damage. Immediate reexploration of the flap was performed in 4 patients, and the flap survived in three of them. There was one necrosis of the grafted split-thickness skin on the survived LD flap. LD free flap was considered as one of the good methods, for the reconstruction of the large soft tissue defect of the limb.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.81-81
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• 2008

Applications of CdS films in this study are to exhibit a high conductivity when they are exposed at light with visible wavelength and sequentially to show a low conductivity in dark state. For this purpose, CdS films should have a high photosensitivity, still maintaining a high conductivity at a visible light. In this study, CdS films were prepared at room temperature on glass substrates by rf magnetron sputtering. In order to increase the photo-conductivity in visible light, various defect levels should be located within the CdS band gap. In order to nucleate the defect sites within the CdS band gap, CdS films were deposited on glass substrates at room temperature using various $H_2$/(Ar+$H_2$) flow ratios by an rf magnetron sputtering. Through the investigation of the structural and photoconductive properties of CdS films by an addition of hydrogen, the relationship between photo- and dark-resistance in CdS films was investigated in detail. 200-nm-thick CdS films for photoconductive sensor applications were prepared at various $H_2$/(Ar+$H_2$) flow ratios on glass substrates at room temperature by rf magnetron sputtering. Sulfur concentration in CdS films crystallized at room temperature with (002) preferred orientation depends directly on the hydrogen atmosphere and the surface roughness of the films gradually increases with increasing hydrogen atmosphere. Films deposited at 8% of $H_2$/(Ar+$H_2$) exhibit an abrupt decrease of dark- and photo-resistance, showing a low photo-sensitivity ($R_{dark}/R_{photo}$). Onthe other hand, films deposited at a hydrogen atmosphere of 42% exhibit a photo-sensitivity of $5\times10^3$, maintaining a photo-resistance of an approximately $2\times10^4\Omega$/square. The dark- and photo-resistance values of CdS films were related with a composition, surface roughness, and defect sites within the band gap.

• 산업경영시스템학회지
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• 제44권2호
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• pp.102-114
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• 2021

NDF (No Defect Found) is a phenomenon in which defects have been found in the manufacturing, operation and use of a product or facility, but phenomenon of defects is not reproduced in the subsequent investigation system or the cause of the defects cannot be identified. Recently, with the development of the fourth industrial revolution, convergence of hardware and software technologies in various fields is spreading to products such as aircraft, home appliances, and mobile devices, and the number of parts is increasing due to functional convergence. The application of such convergence technologies and the increase in the number of parts are major factors that lead to an increase in NDF phenomena. NDF phenomena have a significant negative impact on cost, reliability, and reliability for both manufacturers, service providers and operators. On the other hand, due to the nature of NDF phenomena such as difficult and intermittent cause identification and ambiguity in judgment, it is common to underestimate the cost of NDF or fail to take appropriate countermeasures in corporate management. Therefore, in this paper, we propose a methodology for estimating NDF costs by the PAF model which is a quality cost analysis model and ABC (Activity Based Costing) technique. The methodology of this study suggests a detailed procedure and the concept to accurately estimate the NDF costs, using ABC analysis, accounting system information, and IT system data. In addition case studies have validated the methodology. We think this could be a valid methodology to refer to when estimating the cost of other parts. And, it is meaningful to provide important judgment information in the decision-making process based on quality management and ultimately reduce NDF costs by visualizing them separately by major variable factors.

• Archives of Plastic Surgery
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• 제46권6호
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• pp.589-593
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• 2019

Post-traumatic defects of the distal third of the leg often require skipping a few steps of the well-established reconstructive ladder, due to the limited local reliable reconstructive options. In rare cases, the reconstructive plan and flap choice may encounter challenges when the patient has psychiatric illness affecting compliance with postoperative care. We describe a case of a patient with severe intellectual disability and an open fracture of the distal lower limb. After fracture management and debridement of devitalized tissues, the resultant soft tissue defect was covered with a free gracilis flap. On postoperative day 7, the patient ripped out the newly transplanted flap. The flap was too traumatized for salvage, so a contralateral free gracilis muscle flap was used. The patient showed good aesthetic and functional outcomes at a 1-year follow-up. When planning the postoperative management of patients with psychiatric illness, less complex and more robust procedures may be preferred over a long and complex surgical reconstruction requiring good compliance with postoperative care. The medical team should be aware of the risk of postoperative collapse, focus on the prevention of pain, and be wary of drug interactions. Whenever necessary, free tissue transfer should be performed despite potential compliance issues.

• Archives of Reconstructive Microsurgery
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• 제10권2호
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• pp.93-98
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• 2001

Purpose : This describes our experience with a tenocutaneous free flap from the dorsum of the foot or radial forearm to reconstruct the dorsal skin and extensor tendons of the hand. Material and Methods : Between february 1987 and July 1998, we treated 9 patients with composite tissue loss on the dorsal hand caused by crushing injury. Nine men had an average age of 26.4 years(range, $19{\sim}47$). We treated 5 patients with the free dorsalis pedis flap including the extensor tendons and the superficial peroneal nerve and 4 patients with reverse forearm flap including the brachioradialis tendon and/or superficial radial nerve. Flap size was average 4.4(3,2cm. Evaluation of the results was based on the survived flap rate, the recovery rates for range of motion of the metacarpophalageal joints in the operated fingers. two-point discrimination. Results : All flaps were well vascularized and survived completely. Recovery rates for range of motion of the metacarpophalageal joints in operated fingers range from $78%{\sim}99%$(average, 90%). Two-point discrimination of the transferred flaps in 5 patients average $20{\pm}3.5mm$. Conclusion : The advantages of this procedure are mass action reconstruction with tendon, one-stage operation, faster healing with less adhesion formation, and early mobilization.

• Journal of Korean Neurosurgical Society
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• 제58권2호
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• pp.101-106
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• 2015

Objective : The aim of this study was to explore the immunity in rats transplanted with adipose-derived mesenchymal stem cells (ADSCs) and acellular nerve (ACN) for repairing sciatic nerve defects. Methods : ADSCs were isolated from the adipose tissues of Wistar rats. Sprague-Dawley rats were used to establish a sciatic nerve defect model and then divided into four groups, according to the following methods : Group A, allogenic nerve graft; Group B, allograft with ACN; Group C, allograft ADSCs+ACN, and Group D, nerve autograft. Results : At the day before transplantation and 3, 7, 14, and 28 days after transplantation, orbital venous blood of the Sprague-Dawley rats in each group was collected to detect the proportion of $CD3^+$, $CD4^+$, and $CD8^+$ subsets using flow cytometry and to determine the serum concentration of interleukin-2 (IL-2), tumor necrosis $factor-{\alpha}$ ($TNF-{\alpha}$) and $interferon-{\gamma}$ ($IFN-{\gamma}$) using enzyme-linked immunosorbent assay (ELISA). At each postoperative time point, the proportion of $CD3^+$, $CD4^+$, and $CD8^+$ subsets and the serum concentration of IL-2, $TNF-{\alpha}$, and $IFN-{\gamma}$ in group C were all near to those in group B and group D, in which no statistically significant difference was observed. As compared with group A, the proportion of $CD3^+$, $CD4^+$, and $CD8^+$ subsets and the serum concentration of IL-2, $TNF-{\alpha}$, and $IFN-{\gamma}$ were significantly reduced in group C (p<0.05). Conclusion : The artificial nerve established with ADSCs and ACN has no obvious allograft rejection for repairing rat nerve defects.

• Journal of Genetic Medicine
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• 제12권2호
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• pp.123-127
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• 2015

Distal limb deformities are congenital malformations with phenotypic variability and high genetic heterogeneity. Split hand/foot malformation, also known as ectrodactyly, is a congenital limb malformation characterized by a defect of the central rays of the hands and/or feet. Split hand/foot malformation with long-bone deficiency (SHFLD) is a rare condition related to a 17p13.3 duplication. Recently, genomic duplications encompassing BHLHA9 have been associated with SHFLD. We report a case of SHFLD presenting with campomelia of the right femur, bilateral agenesis of fibulae, bilateral club feet, and oligosyndactyly of the hands and feet, that was associated with a 17p13.3 duplication, as determined prenatally using array comparative genomic hybridization.

• Archives of Reconstructive Microsurgery
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• 제19권1호
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• pp.21-28
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• 2010

Purpose: To report the clinical results of the use of arterialized venous free flaps in reconstruction in soft tissue defects of the finger and to extend indications for the use of such flaps based on the clinical experiences of the authors. Materials and Methods: Eighteen patients who underwent arterialized venous free flaps for finger reconstruction, between May 2007 and July 2009 were reviewed retrospectively. The mean flap size was 4.7${\times}3.2$ cm. The donor site was the ipsilateral volar aspect of the distal forearm in all cases. There were 8 cases of venous skin flaps, 5 cases of neurocutaneous flaps, 4 cases of tendocutaneous flaps, 1 case of innervated tendocutaneous flap. The vascuality of recipient beds was good except in 4 cases (partial devascuality in 2, more than 50% avascuality (bone cement) in 2). Results: All flaps were survived. The mean number of included veins was 2.27 per flap. Mean static two-point discrimination was 10.5 mm in neurocutaneous flaps. In 3 of 5 cases where tendocutaneous flaps were used, active ROM at the PIP joint was 60 degrees, 30 degrees at the DIP joint and 40 degrees at the IP joint of thumb. There were no specific complications except partial necrosis in 3 cases. Conclusions: An arterialized venous free flap is a useful procedure for single-stage reconstruction in soft tissue or combined defect of the finger; we consider that this technique could be applied to fingers despite avascular recipient beds if the periphery of recipient bed vascularity is good.

• 한국항공운항학회지
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• 제13권1호
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• pp.43-49
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• 2005

There are several ways to mold the complex material, and it is divided to vacuum pack mold, compression mold, and hand lay up for a high molecular substance as a basic material. Moreover, it can be divided to general manufacturing (Single form) and mold manufacturing(Mold form) under normal temperature for Firefly. Firefly was manufactured with hand lay up and general manufacturing that using the foam core, glass fabric, and template without mold. However, mold manufacturing that is producing the surface by semi-sandwich using thin foam core and glass fabric then reinforce the inside with spar and rib is on developing. Mold manufacturing can make easy to production, standardize the quality, and possible to mass producing. In this paper, we present the mold producing process for canard aircraft "Firefly", and the problems and solutions during producing Firefly. Moreover, it complements the defect that the problems caused by master manufacturing error when produce several masters of a large part, and make the manufacturing process to be shortened by the replacement from the supplementary plate to the foam that is installed when producing lay up mold.