• 방사성폐기물학회지
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• 제21권4호
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• pp.559-570
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• 2023

The aim of this study is to ensure the structural integrity of a canister to be used in a dry storage system currently being developed in Korea. Based on burnup and cooling periods, the canister is designed with 24 bundles of spent nuclear fuel stored inside it. It is a cylindrical structure with a height of 4,890 mm, an internal diameter of 1,708 mm, and an inner length of 4,590 mm. The canister lid is fixed with multiple seals and welds to maintain its confinement boundary to prevent the leakage of radioactive waste. The canister is evaluated under different loads that may be generated under normal, off-normal, and accident conditions, and combinations of these loads are compared against the allowable stress thresholds to assess its structural integrity in accordance with NUREG-2215. The evaluation result shows that the stress intensities applied on the canister under normal, off-normal, and accident conditions are below the allowable stress thresholds, thus confirming its structural integrity.

• Geomechanics and Engineering
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• 제12권3호
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• pp.417-439
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• 2017

The stone columns are increasingly being used as a soil improvement method for supporting a wide variety of structures (such as road embankment, buildings, storage tanks etc.) especially built on soft soil. Soil improvement by the stone column method overcomes the settlement problem and low stability. Nevertheless, stone column in very soft soils may not be functional due to insufficient lateral confinement. The required lateral confinement can be overcome by encasing the stone column with a suitable geosynthetic. Encasement of stone columns with geogrid is one of the ideal forms of improving the performance of stone columns. This paper presents the results of a series of experimental tests and numerical analysis to investigate the behavior of stone columns with and without geogrid encasement in soft clay deposits. A total of six small scale laboratory tests were carried out using circular footing with diameters of 0.05 m and 0.1 m. In addition, a well-known available software program called PLAXIS was used to numerical analysis, which was validated by the experimental tests. After good validation, detailed of parametric studies were performed. Different parameters such as bearing capacity of stone columns with and without geogrid encasement, stiffness of geogrid encasement, depth of encasement from ground level, diameter of stone columns, internal friction angle of crushed stone and lateral bulging of stone columns were analyzed. As a result of this study, stone column method can be used in the improvement of soft ground and clear development in the bearing capacity of the stone column occurs due to geogrid encasement. Moreover, the bearing capacity is effected from the diameter of the stone column, the angle of internal friction, rigidity of the encasement, and depth of encasement. Lateral bulging is minimized by geogrid encasement and effected from geogrid rigidity, depth of encasement and diameter of the stone column.

• 전자공학회논문지A
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• 제31A권10호
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• pp.79-86
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• 1994

Gain-guided broad-area single quantum well separate confinement heterostructure diode lasers have been fabricated from structures grown by metal organic vapor phase epitaxy. The active layer of the epi-structure is InGaAs emitting 962-965nm and the guiding layer GaAs. The channel width is fixed to 150${\mu}$m and the cavity length varys within the range of 300~800${\mu}$m. For uncoated LD's, the output power of 0.7W has been obtaained at a pulsed current level of 2A, which results about 60% external quantum efficiency. The threshold current density is 200A/cm$^{2}$ for the cavity lengths of 800.mu.m LD's. The stain effect upon the transparent current density has been observed. The internal quantum efficiency is expected to be 88% and the internal loss to be 18$cm^{-1}$. The beam divergence has been measured to be 7$^{\circ}$to lateral and 40$^{\circ}$to transverse direction. finally, 1.2W continuous-wave output power has been obtained at a current level of 2A for AR/HR coated LD's die-bonded on Cu heat-sink and cooled by TEC.

• 전자공학회논문지A
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• 제30A권10호
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• pp.27-32
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• 1993

Separate-confinement hetero-structure (SCH) broad area Laser Diodes (LD's) were fabricated from $Al_{0.07}$Ga$_{0.93}$/. As single-quantum-well (SQW) grown by metal organic chemical vapor deposition (MOCVD). Under pulsed operation, we obtained maximum output powers of about 0.8watt/facet and 1.83watt/facet from LD's with 60$\mu$m and 160$\mu$m channel width, respectively, without facet coatings. The differential quantum efficiency of the 60$\mu$m wide LD was about 21.7%/facet and its threshold current density was about 1k [A/cm$^{2}$]. The differential quantum efficiency of the 160$\mu$m wide LD was about 25.6%/facet and its threshold current density was about 1k[A/cm$^{2}$]. The minimum threshold current density of 60$\mu$m wide LD's was 620[A/cm$^{2}$] when the cavity length was 603$\mu$m and the minimum threshold current density of 160$\mu$m wide Ld's was 675[A/cm$^{2}$] when the cavity length was 752$\mu$m. The internal quantum efficienty and the internal loss of both LD's were 92.3% and 18.1cm$^{1}$, respectively.

• 콘크리트학회논문집
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• 제14권1호
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• pp.33-40
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• 2002

굳지않은 콘크리트를 진공ㆍ감압시켜 제조하는 진공콘크리트는 내부의 공극을 제거하여 조직의 밀실화를 도모하는 것으로 내마모성 및 강도개선 효과가 있는 것으로 알려져 있으며 선진국에서는 건축물 바닥, 댐콘크리트등에 실용화 된 바 있다. 본 연구는 콘크리트 제조과정에서 진공ㆍ감압 수준의 변화와 배합조건에 따른 콘크리트의 강도 및 슬럼프 등과 같은 물리적 특성변화를 관찰하고자 하였으며 연구 결과는 다음과 같다. 진공ㆍ감압콘크리트의 경우, 공기량 저하에 의한 내부공극 감소로 인한 압밀현상으로 단위용적중량과 압축강도가 증진되는 것으로 나타났으나, 시공성, 취성, 내구성능 등에 있어서는 문제 해결을 위한 지속적인 연구가 필요하다.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2007년도 정기총회 및 학술발표대회
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• pp.59-62
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• 2007

The hollow RC(Reinforced concrete) pier has decrease of weight and reduced of materials compared to solid RC pier. However, the hollow RC pier shows a low ductile behavior due to brittle failure of inside concrete. To overcome this problem, the internally confined hollow reinforced concrete column has been developed. In this study, the behavior of internally confined hollow RC piers were evaluated with safety ratio, ductility, total material cost, the total weight of the pier, etc. The chosen parameters for the study are hollow ratio, thickness of internal steel tube, intervals between vertical re-bars, numbers of horizontal re-bars, and strength of concrete.

• Steel and Composite Structures
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• 제1권3호
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• pp.355-376
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• 2001

An experimental research program on end-plate beam-to-column composite joints under cyclic loading is presented. The major focus relates to the identification of the contribution of the concrete confinement in composite columns to the behaviour of the joint, on internal nodes and external nodes, together with an assessment of degradation of strength and stiffness in successive loading cycles. From the experimental results it was possible to identify the various failure modes and to fit the corresponding hysteretic curves to the Richard-Abbott and Mazzolani models. These curve-fitting exercises highlighted the need to adapt both models, either for improved ease of application, or to deal with some aspects previously not covered by those models.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 봄 학술발표회 논문집
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• pp.460-467
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• 1997

Compared to normal-strength concrete, high-strength concrete has the lower lateral expansion capacity caused by the higher elastic modulus and the lower internal crack characteristic. Therefore, the effect of the lateral confining action of hoops appears slowly and also in inefficient Nevertheless. it has been reported that the strength and deformation capacity of high-strength concrete is improved by well-distributed hoops. Due to that argument, this investigation has been compared and analyzed by the experimental works on the deformation capacity and the confinement mechanism of high-strength concrete shear wall of the high-rise building reinforced by rectangular steel tubes and rectangular hoops at both edges of the shear wall.

• 대한토목학회논문집
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• 제31권4A호
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• pp.331-340
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• 2011

콘크리트 공시체의 압축강도와 연성성능을 향상시키기 위하여 섬유-강판 복합플레이트 fiber-sheet and steel-plate composite plate(FSP))의 적용을 실험적으로 연구하였다. FSP 보강재료, 앵커볼트 설치방법, 콘크리트 압축강도 등이 고려된 FSP 보강 콘크리트 공시체의 압축실험을 실시하였다. FSP 보강 콘크리트 공시체의 압축실험결과, FSP는 콘크리트 공시체의 압축강도와 변형저항성능을 크게 향상시켰다. FSP 보강 콘크리트 공시체의 압축성능은 FSP 보강재 종류, 앵커볼트 사용방법, 콘크리트 압축강도에 영향을 받는 것으로 나타났다. 앵커볼트를 사용한 FSP 보강 콘크리트 공시체 실험에서 측정된 FSP의 파단변형률은 FRP 보강 콘크리트 압축부재 실험에서 측정된 FRP 파단변형률보다 크게 측정되었다. FSP 파단변형률의 크기는 FSP의 보강효과에 영향을 미친다. FSP 보강 콘크리트 공시체 압축실험에서 측정된 축방향변형률, 원주방향변형률, 체적 변형률에 의한 FSP 내부 콘크리트의 손상상태를 분석하여 FSP 보강효과를 평가하였다. 연구결과, FSP 보강공법은 콘크리트 압축부재의 보강방법으로 실용적 기법이라 판단된다.

• 미술이론과 현장
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• 제8호
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• pp.123-144
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• 2009

The history of art during the first half of the last decade was founded the discussion with highly impressive and confident. The art might establish its unique area based on self recognition at that era. The self-confidence of modern art may be possible on enlightenment, which is the firm relationship for knowledge and reality. However the faith of modernism which shows rational tendency, objective, and the existence of universal knowledge has been drastically doubted and criticized thereafter. A internal ideological system which had leaded the modern art was exhausted. Postmodernism revolved to the dramatic openness leaning against the deoedipalizational confession. According to the dissipation of the vitality of modern art postmodern art has been evolved and then various phenomena which follow the trends has been emerged. The avant-garde and resisteive attribute of modern art was diluted fast due to the influx of popular culture. As time goes it can be attracted by spectacle taste than metaphysical peculiarity. It has to inevitably justified the drift of light and quick themes, contents, and images. Such as these phenomena realistically shows fact that postmodern art had been failed to open a new chapter of consilience which intermediates beauty and usual communication to overcome the solipsism of modernism. A trial to pursuit the opened esthetics conceived more 'heroic' 'Star-Subject' than before by dismantling the modern 'Hero-Subject'. Postmodernism has been recorded as a regression of art, which is the technology of profound spirit that mitigates antagonism and confrontation and mediates mutual encountering of human being. Prevailing of postmodern freedom had been accompanied by popularity, osetentation consumption, marketing, gambling level exitement, mixtures of desires with price fluctuations. We witness 'self-confinement' and 'lasting absence of exit' phenomena in postmodernism ideology and practice. We have to deal postmodernism as an 'ideology which closes the discussion for the future' in the context of 'absence of way' at this point. We are going to investigate how postmodern ideology and practice takes part in the prospection beyond thereafter through discussion. We also pay attention to the 'absence of prospection' as a internal problem in itself nevertheless mention the three merge points such as tradition or memory, earthy thought, the self who confrontation others as the clue of prospecting thought which is allowing coming over postmodern absence.