• Journal of the Korean Wood Science and Technology
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• 제33권3호통권131호
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• pp.30-37
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• 2005

톱밥과 왕겨를 혼합하여 보드를 제조한 후 페놀수지에 함침율 40~70%로 함침한 후 소성온도 $600{\sim}1200^{\circ}C$에서 소성하여 혼합세라믹을 제조한 다음 수지함침율과 소성온도에 따른 혼합세라믹의 밀도변화, 중량 및 치수감소율과 휨강도를 조사하였다. 수지함침율이 증가함에 따라 소성 후 두께 및 중량 감소율은 감소하였고 밀도와 휨강도는 증가하였다. 소성온도가 증가함에 따라 소성 후 길이, 두께 및 중량 감소율은 증가하였고 밀도는 소성온도 $800^{\circ}C$까지는 증가하다가 $1200^{\circ}C$ 에서는 약간 감소하였다.

• 대한족부족관절학회지
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• 제15권3호
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• pp.144-148
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• 2011

Purpose: To investigate the results of percutaneous repair technique of Achilles tendon ruptures, and to describe the surgical technique. Materials and Methods: We retrospectively analyzed the outcomes of 73 patients with ruptured Achilles tendon from October 1995 to September 2009. 28 patients were excluded due to short follow up period. 34 patients were male and 11 patients were female. The mean patient age was 37.19 (10~62) years. The location of rupture site was 6.58 cm proximal to the tendon insertion into the calcaneus on average. Mean follow up period was 55 months and All patients were surgically repaired using percutaneous technique with sural nerve isolation. Results: Arner-lindholm score were excellent in 32 (71%), good in 12 (27%), poor in 1 (2%) case. 44 cases (98%) had the score more than good. Mean American Orthopedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot function score was 92.93 (67~100). We had 1 case of superficial infection, 1 case of soft tissue irritation by suture knot. Conclusion: Percutaneous repair with sural nerve isolation in treating ruptured Achilles tendon showed low complication rate and reliable clinical outcome.

• 대한소아치과학회지
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• 제34권2호
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• pp.349-353
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• 2007

점액낭종은 소타액선 분비관의 폐쇄나 파열로 타액이 저류되어 발생하는 연조직 부종이고, 비교적 높은 빈도로 발생하는 구강내 가성 낭종으로 스스로 파열되어 치유되기도 하지만 대개는 만성적으로 진행되어 몇 주에서 몇 달간 지속되기 때문에 치료가 필요하다. 점액 낭종의 발생시, 주변에 이환된 소타액선을 포함하여 제거하는 완전절제술 외에 재발율을 낮추기 위한 스테로이드의 국소적 주입, 냉동동결요법(cryotherapy), 미세조대술(micromarsupialization) 등의 여러 가지 치료방법이 제시되고 있다. 완전절제술의 한 방법으로 생검펀치(biopsy punch)를 이용할 수 있는데, 조작이 간편하고 출혈이 적으며 술 후 처치가 거의 필요 없다는 장점이 있다. 이 증례는 점액낭종이 있고 행동 조절이 힘든 소아에서 생검펀치를 사용하여 점액낭종을 완전히 제거한 경우로, 양호한 결과를 얻었다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집A
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• pp.180-185
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• 2001

In the life assessment for plant structural component, the research on deterioration of toughness and material properties occurred in weldments has been considered as very important problems. In general, the microstructures composed in weldments are hugely classified with weld metal(W.M), fusion line(F.L), heat affected zone(HAZ), and base metal(B.M). It has been reported that the creep characteristics on weldments having variable microstructures could be unpredictably changed. Furthermore, it is also known that HAZ adjacent to F.L exhibits the decreased creep strength compared to those in base or weld metals, and promotes the occurrence of Type III and Type IV cracking due to the growth of grains and the coarsening carbides precipitated in ferritic matrix by welding and PWHT processes. However, the lots of works reported up to date on creep damage in power plant components have been mostly conducted on B.M and the creep properties on a localized microstructures in weldments have not as yet been throughly investigated. In this paper, for various microstructures such as coarse grain HAZ(CGHAZ), W.M and B.M in X20CrMoV121 steel weldment, the small punch-creep(SP-Creep) test using miniaturized specimen(t=0.5mm, 0.25mm) is performed to investigate a possibility for creep characteristics evaluation.

• 대한기계학회논문집A
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• 제26권12호
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• pp.2565-2573
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• 2002

A basic research was performed to ensure the usefulness of Small Punch-creep(SP-creep) test for residual life evaluation of heat resistant components effectively. This paper presents analytical results of initial stress and strain distributions in SP specimen caused by constant loading for SP-creep test and its experimental correlations with uniaxial creep(Ten-creep) test on 9Cr1MoVNb steel. It was shown that the initial maximum equivalent stress, ${\sigma}_{eq{\cdot}max}$ from FE analysis was correlated with steady-state equivalent creep strain rate, ${\epsilon}_{qf-ss'}$ rupture time, $t_r$, activation energy, Q and Larson-Miller Parameter, LMP during SP-creep deformation. The simple correlation laws, ${\sigma}_{sp}-{\sigma}_{TEN}$, $P_{sp}-{\sigma}_{TEN}\; and\; Q_{sp}-Q_{TEN}$ adopted to established a quantitative correlation between SP-creep and Ten-creep test data. Especially, the activation energy obtained from SP-creep test is linearly related to that from Ten-creep test at $650^{\circ}C$ as follows : $Q_{SP-P}\;{\risingdotseq}\;1.37 \;Q_{TEN},\; Q_{SP-{\sigma}}{\risingdotseq}1.53\; Q_{TEN}$.

• Wind and Structures
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• 제23권2호
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• pp.157-169
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• 2016

The structural integrity of tube bundles represents a major concern when dealing with high risk industries, such as nuclear steam generators, where the rupture of a tube or tubes will lead to the undesired mixing of the primary and secondary fluids. Flow-induced vibration is one of the major concerns that could compromise the structural integrity. The vibration is caused by fluid flow excitation. While there are several excitation mechanisms that could contribute to these vibrations, fluidelastic instability is generally regarded as the most severe. When this mechanism prevails, it could cause serious damage to tube arrays in a very short period of time. The tubes are therefore stiffened by means of supports to avoid these vibrations. To accommodate the thermal expansion of the tube, as well as to facilitate the installation of these tube bundles, clearances are allowed between the tubes and their supports. Progressive tube wear and chemical cleaning gradually increases the clearances between the tubes and their supports, which can lead to more frequent and severe tube/support impact and rubbing. These increased impacts can lead to tube damage due to fatigue and/or wear at the support locations. This paper presents simulations of a loosely supported multi-span U-bend tube subjected to turbulence and fluidelastic instability forces. The mathematical model for the loosely-supported tubes and the fluidelastic instability model is presented. The model is then utilized to simulate the nonlinear response of a U-bend tube with flat bar supports subjected to cross-flow. The effect of the support clearance as well as the support offset are investigated. Special attention is given to the tube/support interaction parameters that affect wear, such as impact and normal work rate.

• Journal of Chest Surgery
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• 제43권2호
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• pp.194-198
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• 2010

대동맥 벽내 혈종은 대동맥 내벽의 열상 등 손상이 없으면서 대동맥의 혈관벽내의 출혈로 정의되며 고전적인 대동맥 박리로 진행할 수 있는 질환으로 대동맥 박리의 변형된 형태로 여겨지기도 한다. 대동맥 벽내 혈종은 높은 이환율과 사망률을 보이나 궁극적 치료는 아직 확실하지 않다. 하지만 상행 대동맥에 발생한 대동맥 벽내 혈종은 대동맥 파열과 심낭 압전의 위험성으로 인해 보통 수술적인 치료가 고려되고 있다. 저자들은 실신을 주소로 내원한 71세 남환에서 대동맥 벽내 혈종 1예를 수술 치험 하였다. 잘못된 진단으로 인해 응급실 내원 5시간 뒤 시행된 대동맥 단층 컴퓨터 촬영 검사 결과 상행대동맥 벽내 혈종과 심낭 압전 소견이 동반되어 있었으며 이로 인해 급성 신부전, 허혈성 장기손상의 합병증이 발생하였다. 응급 수술로 상행대동맥 및 대동맥궁 치환술을 진행하였고 환자는 수술 14일 뒤 합병증 없이 퇴원하였다.

• Journal of Korean Neurosurgical Society
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• 제59권5호
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• pp.449-457
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• 2016

Objective : Subarachnoid hemorrhage (SAH) caused by rupture of an internal carotid artery (ICA) or vertebral artery (VA) dissecting aneuryesm is rare. Various treatment strategies have been used for ruptured intracranial dissections. The purpose of this study is to compare the clinical and angiographic characteristics and outcomes of endovascular treatment for ruptured dissecting aneurysms of the intracranial ICA and VA. Methods : The authors retrospectively reviewed a series of patients with SAH caused by ruptured intracranial ICA and VA dissecting aneurysms from March 2009 to April 2014. The relevant demographic and angiographic data were collected, categorized and analyzed with respect to the outcome. Results : Fifteen patients were identified (6 ICAs and 9 VAs). The percentage of patients showing unfavorable initial clinical condition and a history of hypertension was higher in the VA group. The initial aneurysm detection rate and the percentage of fusiform aneurysms were higher in the VA group. In the ICA group, all patients were treated with double stent-assisted coiling, and showed favorable outcomes. In the VA group, 2 patients were treated with double stent-assisted coiling and 7 with endovascular trapping. Two patients died and 1 patient developed severe disability. Conclusion : Clinically, grave initial clinical condition and hypertension were more frequent in the VA group. Angiographically, bleb-like aneurysms were more frequent in the ICA group and fusiform aneurysms were more frequent in the VA group. Endovascular treatment of these aneurysms is feasible and the result is acceptable in most instances.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.223-230
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• 2001

The Monkman-Grant (M-G) and its modified parameters were estimated for modified type 316LN and $9{\sim}12Cr-1Mo$ steels with chemical variations. Several sets of creep data were obtained by constant-load creep tests in $550-650^{\circ}C$ ranges. The relation parameters, m, $m^*$, C and $C^*$ were proposed and discussed for two alloy systems. In creep fracture mode, type 316LN steel showed domination of the intergranular fracture caused by growth and coalescence of cavities. On the other hand, the Cr-Mo steel showed transgranular fracture of the ductile type caused from softening at high temperature. In spite of the basic differences in creep fracture modes as well as creep properties, the M-G and its modified relations demonstrated linearity within the $2{\sigma}$ standard deviation. The value of the m parameter of the M-G relation was 0.90 in the 316LN steel and 0.84 in the Cr-Mo steel. The value of the $m^*$ parameter of the modified relation was 0.94 in the 316LN steel and 0.89 in Cr-Mo steel. The modified relation was superior to the M-G relation because the $m^*$ slopes almost overlapped regardless of creep testing conditions and chemical variations to the two alloy systems.

• 한국자동차공학회논문집
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• 제21권1호
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• pp.145-153
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• 2013

In this study, shear punch-creep (SP-Creep) at Sn-4Ag/Cu pad the joint was tested by using environment-friendly Pb-free solder alloy Sn-4Ag of electronic components. Pb eutectic alloy (Sn-37Pb) joints limited to environmental issues with reflow time (10sec, 30sec, 100sec, 300sec) according to two types of solder alloy joints are compared and evaluated by creep strain rate, rupture time and IMC (Intermetallic Compound) behavior. As the results, reflow time increases with increasing thickness of IMC can be seen at overall 100sec later in case of two solder joints on the IMC thickness of Sn-4Ag solder joints thicker than Sn-37Pb solder joints. In addition, when considering creep evaluation factors, lead-free solder alloy Sn-4Ag has excellent creep resistance more than Pb eutectic alloy. For this reason, the two solder joints, such as in the IMC (Cu6Sn5) was formed. However, the creep resistance of Sn-4Ag solder joints was largely increased in the precipitation strengthening effect of dispersed Ag3Sn with interface more than Sn-37Pb solder joints.