• Advances in materials Research
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• 제8권4호
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• pp.275-293
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• 2019

The engine parts material used in gas turbines (GTs) should be resistant to high-temperature variations. Thermal barrier coatings (TBCs) for gas turbine blades are found to have a significant effect on prolonging the life cycle of turbine blades by providing additional heat resistance. This work is to study the performance of TBCs on the high-temperature environment of the turbine blades. It is understood that this coating will increase the lifecycles of blade parts and decrease maintainence and repair costs. Experiments were performed on the gas turbine blade to see the effect of TBCs in different combinations of materials through the air plasma method. Three-layered coatings using materials INCONEL 718 as base coating, NiCoCrAIY as middle coating, and La₂Ce₂O₇ as the top coating was applied. Finite element analysis was performed using a two-dimensional method to optimize the suitable formulation of coatings on the blade. Temperature distributions for different combinations of coatings layers with different materials and thickness were studied. Additionally, three-dimensional thermal stress analysis was performed on the blade with a commercial code. Results on the effect of TBCs shows a significant improvement in thermal resistance compared to the uncoated gas turbine blade.

• 대한기계학회논문집A
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• 제31권4호
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• pp.525-531
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• 2007

The operating temperature has been increased to improve the efficiency of gas turbine. The most advanced Gas turbine is operated at above $1,500^{\circ}C$. Improvement in material and cooling method permit hot gas path component to run at increased temperature. But, the repair of blades which are developed with advanced manufacture technique is difficult to use normal welding. Most of gas turbine blades are made of precipitation harden nickel base superalloy, which is very hard to weld. Therefore, the employment of welding filler on blade is solid solution nickel base superalloy(Hastelloy X, Inconel 617). In this study, Tensile test in high temperature was conducted on welded GTD111DS with GTD111 to evaluate effect of variation of pre, post treatment. The result of this study showed that the specimen was treated with optimum pre and post treatment(preweld HT($1200^{\circ}C$), Post treatment($1100^{\circ}C$ HIP, $1200^{\circ}C$ + $1100^{\circ}C$ + $800^{\circ}C$ HT) is mush superior.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 추계 학술논문 발표대회
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• pp.226-227
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• 2019

Installation and usage methods are currently different between China and Korea for the same rubber asphalt waterproofing sealant. Quality verification is not properly carried out in this situation, so it is necessary to secure reliability in order to export domestic materials to China. In this study, rubber asphalt waterproofing sealant used as injection-type leakage repair material was tested in accordance to adhesion strength quality test method outlined in the JC/T2428 Chinese Industrial Standard to confirm the basic performance is compliant or not.

• Journal of Chest Surgery
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• 제38권4호
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• pp.284-290
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• 2005

본 연구에서는 엡스타인 기형에 대한 수술적 치료의 조기 및 중기 성적에 대하여 알아보고자 하였다. 대상 및 방법 1989년 1월부터 2004년 6월까지 총 29명의 환자들을 대상으로 하였다 중심 연령은 11.4세(4일$\~$50세)이었다. Grade 3 이상의 삼첨판막 폐쇄부전을 동반한 환자는 21명$(72.4\%)$이었다. 수술 방법은 삼첨판막 성형술 및 주름성형술 14예, Carpentier성형술 7예, 삼첨판막 치환술 4예, 체폐동맥 단락술 2예, 삼첨판막 성형술 1예, Fontan수술 1예이었으며, 양방향성 상대정맥-폐동맥 단락술이 5예에서 추가적으로 시행되었다. 신생아기에 수술을 받은 2명 중 1명은 양심실 교정을 받았고, 또 다른 1명은 체폐동맥 단락술을 시행 받았다. 조기 사망례를 제외한 28명의 환자들 중 21명에서 추적관찰이 가능하였으며$(75\%)$, 평균 추적기간은 37.6개월(3개월$\~$11.3년)이었다. 결론: 1명$(3.4\%)$의 조기 사망과 1명의 만기 사망이 발생하였다. 4명의 환자들에서 재수술이 시행되었다. 2명은 삼첨판막 재치환술을 시행 받았고, 2명은 삼첨판막 재성형술을 받았다. 추적관찰이 가능했던 21명의 환자중 grade 3 이상의 삼첨판막 폐쇄부전을 보인 환자는 2명이었으며, 대부분의 환자에서 현저한 증상의 개선을 보였다. 삼첨판막 치환술을 시행 받은 환자들을 제외하고 Kaplan-Meier 방법으로 산출한 삼첨판막과 관련한 재수술이 없을 확률은 1년 및 5년에 각각 $94.7\%,\;79.0\%$이었다. 결론: 대부분의 환자에서 판막 성형술이 가능하였으며, 이의 중기 성적은 비교적 양호하였으나 장기간의 추적관찰이 요구된다. 대부분의 환자에서 현저한 증상 및 혈역학적 개선을 보였다. 다섯 명의 환자들$(17\%)$에서 양방향성 상대정맥-폐동맥 단락술이 시행되었으며, 이의 적응증에 대한 추가적인 연구 및 추적 관찰이 필요하리라 생각한다.

• 대한관절경학회지
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• 제4권2호
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• pp.123-127
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• 2000

목적 : 전방 십자 인대 파열 후 일차적 봉합술을 이용한 수술적 치료 결과에 대해서 알아 보고자 하였다. 대상 및 방법 : 전방 십자 인대 봉합수술을 받았던 25례를 대상으로 IKDC 평가표와 Lysholm score를 이용한 임상적 결과 및 KT-2000 arthrometer를 이용한 이완도를 평가하였다. 대상환자 중 18례에서는 pull-out suture를 시행하였으며, 7례에서는 박근 및 반건양근을 이용한 인대 강화술을 시행하였다. 결과 : IKDC 분석 결과, 전체 환자중 3례에서 A군으로, 13례에서 B군으로, 9례에서 C군으로 평가되었다. Lysholm score는 평균 83점이었다. KT-2000 arthrometer를 이용한 인대 이완도 평가에서는 20lb에서 평균 전방 전위는 3.89mm이었으며, 30lb에서는 평균 7.3mm의 전방 전위를 보였다. 건측 무릎과 환측 무릎의 평균 전방전위도 차이는 20lb에서 1.09mm이었으며, 30lb에서 2.29mm이었고 건측과 환측의 차이는 통계학적으로 유의한 차이가 있었다. 결론 : 봉합술을 시행한 환자에 있어 IKDC라 Lysholm score는 재건술을 시행한 후 평가한 여타 보고에서의 결과보다 만족스럽지 못하며, KT-2000 arthrometer를 이용한 이완도 평가에서도 건측 무릎에 비해 많은 전방 전위를 보였던 바, 특히 젊고 활동성이 많은 환자에 있어서 인대 봉합술 보다는 재건술을 시행하는 것이 좋을것으로 사료 된다.

• Journal of Chest Surgery
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• 제39권3호
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• pp.214-219
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• 2006

배경: 식도천공은 비교적 흔하지 않지만, 높은 이환율과 사망률을 나타낸다. 치료와 결과는 증상의 시간에 따라 크게 결정된다. 저자들은 식도천공 환자들을 최근의 치료방법으로 치료하여 결과를 후향적으로 조사하여 보았다 대상 및 방법: 1990년 3월부터 2005년 3월까지 식도 파열로 치료한 환자들을 후향적 분석하였다. 28명 환자들에서(남자 22명, 여자 6명: 평균나이 51세, 최소 17세에서 최고 82세)천공의 원인을 보면 이물질 9명, 외상 7명, 자연적 파열 7명, 의인성 5명이었다. 환자중 18명은 24시간 내 진단되었으며, 10명은 24시간 이후에 진단되었다. 21명($75\%$)에서 일차 봉합술을 시행하였으며, 4명에서는 식도 절제술, 3명의 환자에서는 위루술과 배농술를 시행하였다. 결과: 병원 사망률은 $18\%$이며, 그리고 의인성에서 사망률이 증가하였다(p <0.05). 천공위치, 천공 후 시간, 치료방법은 사망률에 영향을 미치지 못했다. 수술 후 누출은 4명의 환자에서 생겼으며, 보존적인 치료로 회복이 되었다. 결론: 식도 파열은 진단과 치료가 어렵기 때문에 아직도 위험한 질환이다. 대부분의 환자에서 증상의 발현시간에 관계없이 일차 재건술이 사망률을 낮출 수 있다. 정확한 진단과 조기 치료가 식도파열 환자들의 성공적인 치료에 필수적이다.

• Corrosion Science and Technology
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• 제2권6호
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• pp.266-271
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• 2003

Safety diagnosis of various structural components and facilities is indispensable for preventing catastrophic failure of material by time-dependent and environment accelerating degradation. Also, this diagnosis of operating components should be done periodically for safe maintenance and economical repair. However, conventional standard methods for mechanical properties have the problems of bulky specimen, destructive procedure and complex procedure of specimen sampling. So, a non-destructive and simple mechanical testing method using small specimen is needed. Therefore, an advanced indentation technique was developed as a potential method for non-destructive testing of in-field structures. This technique measures indentation load-depth curve during indentation and analyzes the mechanical properties related to deformation such as yield strength, tensile strength and work-hardening index. In this paper, we characterized the tensile properties including yield and tensile strengths of the V-modified Cr-Mo steels in petro-chemical and thermo-electrical plants. And also, the effects of hydrogen-assisted degradation of the V-modified Cr-Mo steels were analyzed in terms of work-hardening index and yield ratio.

• Journal of Chest Surgery
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• 제33권1호
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• pp.7-19
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• 2000

Background :To assess the accuracy of Electron-Beam Tomography(EBT) in following evaluation of the pulmonary vascular system after a shunt operation in the cyanotic con-genital heart disease with pulmonary stenosis or pulmonary atresia. Material and Method : Sixteen patients(M:F=11:5) who received Blalock-Taussig(n=8) bidirectional cavo-pulmonary shunt(n=10) and unifocalization (n=2) were ncluded in the study. We evaluated the patency of the shunt the morphology of intrapericardial and hilar pulmonary arteries(PA) peripheral pulmonary vascularity by background lung attenuation and the abundance of arterial & venous collateral. Angiography(n=12) and echocardiography(n=20) were used as the gold standard for the comparison of EBT results. Result: EBT was consistent with angiogram/ echo in 100% of the evaluation for the patency of the shunt and in 12(by angiogram 100%) and 19(by echo 95%) for the detection the hypoplasia stenosis or interruption of central PA In measuring of PA EBT and angiogram corrlated(r=0.91) better than EBT-echo(r=0.88) or echo-angiogram(r=0.72) Abundant systemic arterial collateral were noted in 4 and venous collateral in 3 cases. In evaluating the peripheral pulmonary vascularity the homogenous and normal-ranged lung attenuation(m=6) decreased but homo-genous attenuation(n=1) segment-by-sgment heterogeneous attenuation(n=3) homogenous but asymmetrical attenuation(n=3) segment-by-segment heterogeneous attenuation(n=3) homogenous but asymmetrical attenuation(n=3) and venous congestion(n=2) were observed nd 12 of them were compatible with the blood flow pattern revealed by cardiac catheterization. Conclusion: EBT was accurate in the integrated evaluation of the pulmonary vascular system after the shunt including the patency of the shunt operaion the morphology and dimension of the central and hilar PAs and the loco-regional pulmonary flow in the lung parenchyma. It suggests the useful information about the need of secondary shunt operation the proper timing time for total repair and the need of interventional procedure prior to total repair.

• 한국임상수의학회지
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• 제40권1호
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• pp.16-24
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• 2023

This study aimed to compare complete ruptured tendon healing between two different repair methods using the Achilles tendon of New Zealand white rabbits. Thoracolumbar fascia (TF) padded Kessler suture, polypropylene mesh (PM) padded Kessler suture, and Kessler suture only were performed on the completely transected lateral gastrocnemius tendon, and biomechanical and histologic characteristics were assessed after 8 weeks. For biomechanical assessment, the tensile strength of each repaired tendon was measured according to the established methods. For histomorphometric analysis, hematoxylin and eosin staining for general histology, and Masson's trichrome (MT) staining for collagen fibers, Alcian blue (AB) staining for proteoglycans were performed and analyzed. Significant increases in tensile strength with remarkable decreases in the abnormalities against nuclear roundness, cell density, fiber structure, and fiber alignment and significant decreases in the mean number of infiltrated inflammatory cells and AB-positive proteoglycan-occupied regions with increases in MT-positive collagen fiber-occupied regions were demonstrated in the Kessler suture with PM or TF padding groups as compared to those of the Kessler suture group. Both of PM and TF provided potent tensile strength and supported healing with the evidence of histological examinations. This means that augmentation with PM is useful for repairing a completely ruptured Achilles tendon, without additional surgery for autograft material harvesting.

• 수산경영론집
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• 제9권2호
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• pp.59-89
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• 1978

The analyzed results of the actual state of stow net fishery based on the cost expended are as follows. According to the calculation of interests, the total cost of this fishery comes to ￦38,010,653 and in this account, the production cost comes to ￦35,477,198(93.3%), the material cost, 14,567,239(38.3%), the labour cost, 12,740,274(33.5%), the expenses, ￦8,169,685(21.5%), the commision and administration expenses, 2,533,455(6.7%). The expenses for this fishery are paid out as production costs, and the expenses for sale and administration expenses are the lowest of them, and the 93% of expenses are paid out as production costs. The ratio of cost element to 100% is as follow. The wages, 28.4%, fuel, 15.2%, repair, 11.6%, deprecation, 9.5%, fishing gear, 8.7%, ice, 6.1%, container(box for fish), 5.2% administration expenses, 5.2%, food, 3.5%, ship grar, 3.2%, public welfare, 1.7%, commision for sale, 1.5%, insurance for crew, 0.2%, taxes, 0.2%. This fishery is managed with the larger fishing boat than it was and so, it demands better crews with higher wages. In the former fishery, the search for fishing ground is very difficult with long navigation and great fuel consumption. when the weak fishing gears are used, the expenses for their repair and for their gears are greatly paid out. The unit costs of catches to each box come to ￦2.807(￦187 each kg). As the ratio of cost of sales comes to 86.7%and the ratio of interests comes to ￦5,850,812(13.3%), and so the net profit comes to 13.3% of total profits. According to above the ratio of cost of sales is shown as a universal validity, Asthe total expenses comes to 86.7% to the money on sales in the break-even point, the break-even point comes to ￦26,209,168 Accordingly for the profit control the account of production should be raised, and by the saving method of expenditure the break-even point should be brought down for the development of total profits.