압력에 따른 지르칼로이의 수증기내 고온산화

김광표,박광헌 慶熙大學校 材料科學技術硏究所 1998 材料科學技術硏究論集 Vol.11 No.-

To find the effect of pressure on the high temperature oxidation of zircaloy-4, an autoclave capable of measuring the degree of oxidation at high temperatures and high pressure was manufactured. The degree of high temperature oxidation of zircaloy-4 was measured at three different conditions, high pressure steam, high pressure Ar gas with small amount of steam, and 1 atm steam. All the measurements were done at 750℃. The oxide thickness is much thicker in high pressure steam, comparing to that in the 1 atm steam. And, the higher is the steam pressure, the thicker becomes the oxide. No effect was observed in the case of high pressure Ar containing small amount of steam. Many cracks exist on the surface of specimens oxidized at high pressure steam, which come from the enhanced tetragonal to monoclinic phase transformation due to high pressure steam. The enhanced oxidation seems due to oxide cracking.

수소저장합금의 제조기술과 특성평가에 관한 연구

김광배,山川宏二,홍준표 한국항공대학교 1994 論文集 Vol.32 No.-

본 연구의 목적은 수소저장합금의 합금설계, 열처리방법과 특성평가를 연구하는데 있다. 시편은 플라스마 아크로로 용해한 후 1100℃에서 15시간 균질화처리한 후 분말로 제조해서 사용하였다. 수소저장 및 방출실험은 P-C-T 곡선을 통해서 평가하였다. 평가결과 Fe-Ti합금에 소량의 Mn을 첨가한 합금이 수소저장 및 방출 속도가 우수했고 수소활성화 속도도 양호했다. Fe-Ti-Mn 합금이 주로 사용되는 수소저장용 용기 및 열교환기등에 사용이 가능하다고 사료된다. The purpose of this study is fabrication method, alloy design, heat treatment and hydriding reaction, were studied on the hydrogen absorbing alloy, In case of the specimen which were held at 1100℃ for 15hr after melting in the plasma are furnace. Hydriding reaction of hydrogen absorbing alloy by Pressure-Consentration-Temperature(P-C-T_ curve, was investigated. When a small amount of Mn is Substituted for Fe in FeTi alloy, hydriding reaction rate were increased significantly. And the hydriding characteristics of the Fe-Ti-Mn alloy showed the best result at P-C-T curve.

선천성 고관절 탈구에 대한 관절 조영술의 임상학적 연구

이광진,고광표 충남대학교 의과대학 지역사회의학연구소 1994 충남의대잡지 Vol.21 No.2

Arthrography can verify the state of the soft tissues situated between the femoral head and acetabulum in congenital dislocation of the hip. And it is known to be the most accurate and certain way of demonstrating lesser degrees of incongruity. It can visualize the intrinsic obstructive factors. We analyzed 39 cases of congenital dislocation of the hip in 34 patients, which had been evaluated by arthrography and followed up for more than 2 years postoperatively. 8 patients had involvement of the right hip : 21, involvement of the left. hip : and five, bilateral involvement. Prereduction arthrography showed following observation : subluxation in 8 cases(20.5%), dislocation in 31 cases(79.5%), deformed limbus in 31 cases(79.5%), hourglass capsular configuration in 15 cases(38.5%), shortened transverse acetabular ligament in 11 cases(28.2%), ligamentum teres hypertrophy in 8 cases(20.5%). Reduction arthrography showed following observations : adequate reduction in 24 cases(61.5%), inadequate reduction in 15 cases(38.5%) with medial dye pooling more than 2mm. Adequate reduction was obtained in 24 cases(61.5%) and were treated by closed reduction. Deformed limbus with medial dye pooling more than 2 mm was considered as inadequate reduction and there were 15 cases(38.5%) of this kind reduction. They were treated with open reduction in 6 cases, open reduction with innominate osteotomy in 5 cases, open reduction with femoral varization osteotomy in 2 cases. Clinical results were classified as Excellent in 28 cases(71.8%), Good in 10 cases(25.6%) and Fair in 1 case(2.5%) according to Gibson and Benson. Radiologic results were classified as Excellent in 10 cases (25.6%), Good in 9 cases(23.1%), Fair in 15 cases(38.5%), Poor in 5 cases(12.8%) according to Severin. We conclude from this study that arthrographic investigations can play a useful role in the diagnosis of the cause of the obstruction in CDH and thus help to determine proper management.

通度寺 空間構成形式의 變化過程과 特徵的 現象에 관한 硏究

洪光杓 동국대학교 사찰조경연구소 1992 寺刹造景硏究 Vol.1 No.-

The purpose of this study is to analyzing and interesting the transformation process and characteristic phednomena showed in the spatial organization form of Tongdo-sa(temple). This study was mainly performed through out the review of the related old literary works and a survey map. The results obtained are as folling: 1. The symbolic meaning of the first construction form of Tongdo-sa was respresented to Keumkangkedan(金剛戒壇, stupa). 2. The characteristic phenomena showed in the spatial organization form of Tangdo-sa was accomplished to change its center. 3. The space organizing center of Tongdo-sa was transformed by change its central axis.

초경량성 재료인 Mg-10Li-3A1 합금의 TMP 처리를 통한 기계적 특성 향상 방안

김광배,홍준표,김영인,홍원식,배현근 한국 항공대학교 항공산업기술연구소 1998 航空宇宙産業技術硏究所 硏究誌 Vol.8 No.-

초경량 고강도 Mg-10Li-3Al 합금이 용탕단조법에 의해 제조되었다. 주도된 상태의 미세구조는 β상 기지에 균일하게 분포된 AlLi 및 MgAl₂Li를 포함하는 HCP α상과 BCC β상으로 이루어졌다. α상의 초기 결정립 크기는 100㎛였다. Mg-Li 합금에 Al을 첨가하는 것은 용체화 처리 및 시효를 통한 석출 경화에 기인하여 합금의 강도 및 경도를 향상시켰다. 결정립 미세화를 위한 TMP처리가 냉간 가공과 연이은 300℃, 30분 동안의 어닐링에 의해 수행되었다. 결과적으로 나타나는 미세구조는 재결정화되지 않은 α상과 재결정화된 β상으로 이루어졌다. 냉간 가공량이 증가함에 따라 합금의 결정립 크기가 감소하였고, 최종 결정립 크기는 3.5㎛였다. 가공 열처리된 Mg-10Li-3Al합금은 용탕단조된 합금보다 높은 강도와 연신율을 보였다. Superlight and high strength Mg-10Li03Al alloys were fabricated by squeeze casting. The as-casted microstructure was consisted of a mixture of a mixture of HCP α and BCC β phases including AlLi and MgAl₂Li precipitates, which were uniformly distributed in the βmatrix. Initial grain size of α phases was 100㎛. The addition of Al in Mg-Li alloy had improved the strength and hardness due to the precipitation hardening through solution heat treatment and aging. Thermomechanical Processing(TMP) for grain refinement was carried by cold working and immediate annealing for nucleation at 300℃ for 30 minutes. Subsequent microstructure was consisted of unrecrystallized α and recrystallized β phases. The more the amount of cold working increased, the more the grain size of the alloy was decresed. Final grain size was 3.5㎛. Thermomechanically processed Mg-10Li-3Al alloy had higher strength and elongation than as-casted alloy.

寺刹의 蓮池에 관한 硏究

洪光杓 동국대학교 사찰조경연구소 1997 寺刹造景硏究 Vol.5 No.-

The purpose of this paper was to identify the philosophical principles of lotus ponds based on buddhism as well as the design principles. The results showed that buddhism influenced the design of lotus ponds from the beginning in traditional temples, and this design tradition has maintained with some changes in physical form and location of lotus ponds. Also lotus ponds were used as important parts of temples and strongly symbolize buddhist philosophy. It was found that lotus ponds made in the early years of buddhism were usually located at the outside of the middle gate in temples. The location were changed as buddhism prospered, specifically, lotus ponds were moved to the central area in temple and became ornamental elements, which showed the symbolism of ponds were weakened. As the meaning of lotus ponds were changed, their forms were changed from square to circle or oval.

메탄올/가솔린 혼합연료의 베기가스 분석 연구

홍광표,박명호,김성준 江原大學校 産業技術硏究所 1997 産業技術硏究 Vol.17 No.-

DOHC gasoline engine(4-cylinder in line type, 1600cc) is modified for the experiment to develope an alternative fuel. The modified engine is tested with the various combination of gasoline and methanol. Pollutant emissions of CO and HC are measured at the end of exhaust manifold. The concentration of CO and HC in exhaust gas is greatly reduce with the increase of coolant temperature of engine. HC concentration is reduced until methanol content reaches to thirty percent and then increased with the volumetric percentage of methanol in fuel. On the other hand, the concentration of CO is reduced as the methanol centent is increased up to 20 percent and then it becomes constant e en though the methanol content is raised. The effect of engine RPM on the HC and CO exhaust is investigated. HC concentration is reduced as the engine RPM is increased but the typical trends of variation are not found in the measured value of CO concentrations.

이동호스트를 위한 적응성 멀티캐스트 알고리즘

홍영표,안광수,백덕화 진주여자전문대학 2001 論文集 Vol.24 No.-

To Provide multicast service for mobile hosts must deal with dynamic member location and its group membership in mobile networks. There are two old approaches as hi -directional tunneling and remote subscription for mobile multicast. The deployment of existing multicast protocols(home agent-based multicast, Bidirectional packet tunneling) is very inefficiently to use network resources such as duplicate copies of multicast datagrams, tunnel convergence, and unicast by long delivery path. The remote subscription scheme may be very expensive because muticast packet delivering is delayed and discontinued frequently by rebuilding a multicast tree to serve multicast when the host move highly. In this paper, we analyse these problems of multicast routing protocols and propose an efficient multicast protocol using cost function to consider the host mobility in wireless mobile networks, By cost function, a mobile host make a decision to receive a tunneled multicast datagram from home agent or to receive a rebuild path from foreign agent. The performance of the proposed protocol was evaluated by simulation under various environments and we got an improved performance.

X선 프렉토그래피기법을 이용한 금속복합재료의 피로손상 해석에 관한 연구

김광영,박동성,박영철,윤두표,김득진 韓國非破壞檢査學會 1998 한국비파괴검사학회지 Vol.18 No.3

본 연구에서는 비파괴방법중 대단히 효과적인 방법이라 할 수 있는 X선 프렉토그래피 방법을 이용하여 파괴역학적 파라메타인 ΔK, Kmax의 정량적인 평가의 가능성에 대하여 검토하였다. 이를 위하여 Al2009-15v/o SiCw 복합재료와 SS41 불림재를 이용하여 피로균열진전시험을 실시하고 그 결과로부터 파면상의 X선 프렉토그래피 파라메타와 파면형성시의 파괴역학적 파라메타를 비교 ㆍ검토하여 X선 프렉토그래피에 의한 ΔKdhk Kmax의 평가 방법에 대하여 연구하였다. 또한, 정적하중부에 의한 소성변형률의 비파괴적 평가법에 대하여도 검토하였다. 이를 위하여 인장시험으로 소성변형을 부하한 후, X선 프렉토그래피 파라메타를 이용하여 부하된 소성변형량의 비파괴평가법에 대하여 검토하였다. 그 결과 피로파괴시의 부하된 Kmax와 피로손상 정도를 X선 프렉토그래피에 의하여 정량적으로 평가할 수 있는 방법을 제시하였다. It is attempted to verify the Quantitative relationship between fracture mechanical parameters(ΔK, Kmax)and X-ray parameters (residual stress, half-value breadth) of Al2009-15v/o SiCw composite, and normalized SS41 steel. In this study, fatigue crack propagation test were carried out X-ray diffraction was applied to fatigue fractured surface in order to investigate the change of residual stress and half-value breadth on fatigue fractured surface. And it is loaded prestrain to each tensile specimen, Al2009-15v/o SiCw composite(0.3,0.5,1,1.5,2%) and normalized SS41 steel(0.63,7.50,13.7,20%),for investigating plastic strain rate using nondestructive measurement method. X-ray diffraction was applied to the prestrained tensile specimens in order to measure the change of residual stress and half-value breadth.

사찰환경의 보존에 관한 연구

홍광표 동국대학교 사찰조경연구소 1996 寺刹造景硏究 Vol.4 No.-

This study was to make clear the present status of the environmental problem of Korean temples and to propose the conservation means of them. The result of this study obtained are as following ; In order to continuously conserve the environment of temples, follwing efforts have to be made. Firstly, to conserve the environment of temples, the attitude of mind toward environment have to be changed. Secondly. the best method of conserve the environment of temples is to restrict the development of the temple area as much as posible. But of it becomes inevitable to develop the environment, development must start after the conservation planning has been set. Thirdly, the pollution of temple environment has to be minimized and resulting pollution should be properly taken care of. Fourthly, to reasonable conserve the temple environment, the legislative and systematic institution is urgently needed. Lastly, to conserve the temple environment, financial support should be fully cinsidered.