• Journal of Chest Surgery
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• 제12권1호
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• pp.56-60
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• 1979

Replacement of the aortic valve in a normal or large aortic root can be accomplished with ease and safety in most instances. The presence of a narrowed aortic annulus remains a problem in that the replaced smaller prosthetic valve has a significant resting pressure gradient across the orifice. This narrowing causes not only technical difficulties, but also increased mortality and post-op. complication. Therefore this problem deserves special attention. This report presents our experience with a case of a small aortic root caused by rheumatic heart disease [AI and MS]. This is the method of enlargement of the aortic annulus with a woven Dacron patch and replacement of a larger prosthetic aortic valve combined with mitral valve replacement.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1996년도 제24회 추계학술대회
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• pp.189-194
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• 1996

The modern orthopaedics frequently uses the total hip replacement in the artificial hip joint. The wear in this joint requires the re-replacement of the hip joint beacuse it is under the severe load and friction conditions. To solve these problems the previous studies have been mainly focused on the development of the new materials. The research of new material, however, needs much time and effort since it should be experimented for its bio-compatibility, friction, and wear characteristics. To reduce the work, in this study, the finite element analysis is applied to find the new combination of the materials in the total hip replacement which has the excellent contact characteristics. The finite element uses MARC and the 5-node aximetric element. The results show that in case of acetabulum UHMWP has good characteristics, in femoral head, the $Al_2O_3$, and in stem, Ti6Al4V.

• 산업공학
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• 제15권1호
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• pp.89-98
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• 2002

This paper considers the optimum replacement times of a steam generator in nuclear power plant with failure data. It is assumed that the failure pattern of units is given as a Weibull distribution and repair and periodic preventive maintenance are performed periodically. The maximum likelihood method is used to estimated the Weibull parameters of failure distribution from failure data. Relpacement, output-decresing and maintenance costs are considered to determine the optimal replacement times by simulation. Numerical examples are included with actual failure data and cost estimators.

• 한국경영과학회지
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• 제10권1호
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• pp.65-78
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• 1985

In this paper, the approach getting a total demand by forecasting the new demand and the replacement demand separately and adding them is used for long term forecasting of durable goods. Cross country analysis using the income as an independent variable and S-shaped growth curve as a fitting model is developed as a method of forecasting new demand. To get the replacement demand the methods using the number of ownership and the replacement rate and the methods using the past demand and the distribution of the product life are proposed. And the theoretical explannation for product life cycle's diversity, which is the one of the major considerations in the long term forecasting, is attempted by the combination of the new demand and the replacement demand patterns. This is applicated the long term forecasting of Korean passenger cars.

• Journal of Chest Surgery
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• 제28권6호
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• pp.579-582
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• 1995

The extended transseptal approach to the mitral valve replacement has been used for 30 patients. There were 19 women and 11 men. Twenty five patients had rheumatic heart disease, 4 had degenerative valve ,and 1 had valve prolapse. Fifteen of 30 patients had other associated procedure; 10 had aortic valve replacement; 5 had tricuspid annuloplasty. There were no postoperative complications associated with the approaches, ie, no bleeding, no sinus node dysfuction, and no atrioventricular conduction disturbance. Despite division of the sinus node artery, preoperative atrial rhythms[3 sinus rhythms and 27 atrial fibrillations were not changed during postoperative period. The extended transseptal approach provides good mitral valve exposure without inherent complications, and is superior to that of standard approach, so we use it routinely for mitral valve procedure.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.966-973
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• 2005

The stress concentration ratio in accordance with area replacement ratios were considered as core elements of design. However, the stress concentration ratio will be vary depends on progress of consolidation in clay ground. And, since it is not sure to know the affecting factors accurately, the value is decided based on field experiences. To use SCP method more effective and correspond to soil improvement, the decision on proper area replacement ratio through the exact stress concentration ratio is very important. Accordingly, a numerical analysis on influence of various factors that needed to make rational designing guide for decision of proper area replacement ratio to stress concentration ratio was executed in this study.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2003년도 학술.기술논문 발표회
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• pp.5-8
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• 2003

As a part of efforts to obtain high quality and economical efficiency of concrete, blast-furnace slag has been utilized by means of cement replacement. Therefore superior performance can be ensured, environmental pollution can be prevented and economical advantage can be obtained with utilization by cement replacement. But the studies on the blast-furnace slag are not systematic and reasonable. So, it was planed that basic data in regard to technique of manufacturing and economic improvement of concrete is showed with experimental comparison and investigation of engineering properties of concrete utilizing blast-furnace, industry by-product, as cement replacement in this study.

• 대한족부족관절학회지
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• 제15권2호
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• pp.102-106
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• 2011

Recently, development and improvement in joint replacement therapy, the need for arthrodesis has been decreasing. However, result of joint replacement is not always satisfactory, and most cases are rather indicative to ankle arthrodesis than ankle replacement. Often, ankle arthrodesis can be more beneficial salvage method to treat cases with failure in joint replacement therapy, talar avascular necrosis with massive bone defect, talus fracture with severe comminution and bone defect and ankle dislocation. In cases with large bone defect that need to be treated with ankle arthrodesis using internal fixation, it is difficult to fill the defect with conventional auto-iliac bone or all-bone graft. Thus, we make a report on our experience in treating 2 cases with ankle arthrodesis using auto-fibular bone graft and plate fixation.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2003년도 학술.기술논문발표회
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• pp.5-8
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• 2003

As a part of efforts to obtain high quality and economical of efficiency of concrete, blast-furnace slag has been utilized by means of cement replacement. Therefore superior performance can be ensured, environmental pollution can be prevented and economical advantage can be obtained with utilization by cement replacement. But the studies on the blast-furnace slag are not systematic and reasonable. So, it was planed that basic data in regard to technique of manufacturing and economic improvement of concrete is showed with experimental comparison and investigation of engineering properties of concrete utilizing blast-furnace, industry by-product, as cement replacement in this study.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.249-252
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• 2006

When concrete is subjected to uniaxial compression, the failure process is normally initialed from a localized zone. The localization of failure governs structural behaviors of concrete. In this paper, the compressive strength and failure behavior of recycled coarse aggregate concrete with different replacement level of recycled coarse aggregates are investigated using acoustic emission(AE). AE characteristics of concrete were investigated during the entire loading period. For these purpose, four recycled coarse aggregate replacement level (i.e 0%, 30%, 60% and 100%) were considered in this paper. Result from this study show AE signal, AE method can apply to investigate a compressive failure mode according to recycled coarse replacement level.