• 한국전기전자재료학회논문지
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• 제33권4호
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• pp.263-270
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• 2020

In this study, the physical mechanism and diffusion effects in aluminium implanted silicon was investigated. For fabricating power semiconductor devices, an aluminum implantation can be used as an emitter and a long drift region in a power diode, transistor, and thyristor. Thermal treatment with O₂ gas exhibited to a remarkably deeper profile than inert gas with N₂ in the depth of junction structure. The redistribution of aluminum implanted through via thermal annealing exhibited oxidation-enhanced diffusion in comparison with inert gas atmosphere. To investigate doping distribution for implantation and diffusion experiments, spreading resistance and secondary ion mass spectrometer tools were used for the measurements. For the deep-junction structure of these experiments, aluminum implantation and diffusion exhibited a junction depth around 20 ㎛ for the fabrication of power silicon devices.

• 한국세라믹학회지
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• 제17권4호
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• pp.197-202
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• 1980

The oxidation mechanism of the not sintered pellets and sintered bodies of $Si_3N_4$ was investigated. in air over the temperature range of 800~130$0^{\circ}C$. The $\beta$-cristobalite was instantaneously formed and covered the particles of powder packed in the not sintered and weakly sintered porous $Si_3N_4$ bodies by molecular diffusion of oxygen through the porous Si3N4 bodies and an immediate oxidation. The diffusion of oxygen ion through the formed $\beta$-cristobalite surface layer is assumed to control the further oxidation of the $Si_3N_4$ particles of the porous $Si_3N_4$ bodies. The diffusion coefficients and activation energies of oxygen ion through the $\beta$-cristobalite layer were obtained by the use of a derived equation.

• 한국해양공학회지
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• 제24권4호
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• pp.78-85
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• 2010

This study investigates reducing characteristics for the spreading of dredged soil and the diffusion of contaminant by silt protector curtain through three dimensional numerical experiment. The numerical medel is modified by combining the sediment transport characteristics for cohesive sediment into the previously developed model. Several numerical experiments have been given in order to investigate the reducing effect of silt protector using two dimensional numerical channel model under various parameters such as upstream flow velocity, depth of silt curtain and the position of dumped materials. Through the evaluation of several simulation results, we knew that the careful design has to be given in the determination of depth and position of silt protector.

• 한국막학회:학술대회논문집
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• 한국막학회 1995년도 춘계 총회 및 학술발표회
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• pp.34-35
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• 1995

The unique feature of pervaporation is the mass transfer from a liquid phase to a vapor phase through a non-porous polymeric membrane. When a liquid mixture is brought into contact with a membrane at one side, it is sorbed into the membrane. Due to a driving force applied across the membrane, the sotbed liquid molecules permeate through the membrane and evaporate at the downstream side of the membrane. In pervaporation the permeated species are usually removed from the downstream side under a relatively low vapor pressure, for example by evacuation with a vacuum pump. As far as this condition is fulfilled, the evaporation step can be considered to be much faster than sorption or diffusion. Hence evaporation does not contribute to permselectivity. Therefore the separation by pervaporation results from the differences in the preferential sorption of the individual components of a mixture into the membrane together with the diffusion rates through the membrane. This postulation implies that both sorption and diffusion phenomena have to be accounted for to understand the physico-chemical nature of the pervaporation separation process.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 춘계 학술논문 발표대회 2부
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• pp.99-104
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• 2011

Daylighting system is an alternative to the energy crisis and environment change. And it is possible improvement system of Architectural Space Environment. Accordingly, it is very useful system. Because Daylight Duct System of Daylighting System gives high performance for its price, distribution rate is very high. But Daylighting Duct System is hard to accurate control. Accordingly, it is difficult to maintain continuously Daylight Environment in Interior Spaces. Lighting Diffusion System has been developed that it is Applying the principle of Reflector and prism diffuser for maximize the efficiency of lighting of Daylight Duct Systems through this study. And then compare lighting performance of Existing System and new Lighting Diffusion System through producing a mock-up. Thus, this study was carried out for the purpose of verification for excellence. It is that installed Each Daylighting Duct System for performance evaluation in a laboratory of width 4m, length 10m, height 2.5m. And illuminance was measured at noon on winter solstice(December 22) under clean sky. The actual measurement result was in the following. Newly developed lighting Diffusion system was measured maximum illuminance 399, minimum illuminance 221, average illuminance 141. Synthetically, daylight factor, uniformity factor and illuminance distribution were improved more than existing system. As a result, it was confirmed that was improved lighting Environment in Interior Spaces.

• 한국주거학회:학술대회논문집
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• 한국주거학회 2009년 춘계학술발표대회 논문집
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• pp.332-337
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• 2009

The stronghold diffusion style method is resident participation style residential environment improvement plan that first of all, the general public constructs base facilities which the temporary occupancy public housings, commonness use facilities, roads, etc. And then with using the public housing of the stronghold sector, the resident oneself improves the house with independence or commonness. As a result induction of the voluntary participation of economic situation and the resident where the improvement will is reflected and introduction of versatile maintenance method through stronghold development with participation of the general public, this study tries to present the residential improvement method of diffusion style. San-Jun was selected in the subject of investigation area in stronghold diffusion style residential environmental improvement plan area. Investigation contents population register quality and quality of present house, the degree which is a house environmental improvement plan, about residential improvement the fact etc. Because unsatisfactorily in compliance with the deterioration and spatial narrow of the house, The above of half is an improvement intention. Hereafter residential improvement, According to the condition which is economic, residential improvement will change. The plan will be able to augment the economic enemy capability of the resident should grope and the residents oneself creates the environment will be able to improve the house. Also with creating, activating a resident organization, through autonomous decision-making process, the residential improvement could be advanced continuously.

• 한국토양비료학회지
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• 제28권3호
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• pp.233-240
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• 1995

Ficks의 확산 편미방을 Laplace 변환을 적용하여 초기 및 경계조건과 함께 종속 대수 함수로 변환하고 Burington의 역변환표를 활용하여 복귀하는 방법으로 Ficks의 확산 편미방의 해를 구하였다. 적용된 초기 및 정계조건은 일정깊이의 담수에로 무한 깊이의 일정 염농도의 균일한 간척지 토양에서 상향 염분확산 이동에 대한 것이었다. 유도된 해는 특이 조건에서의 비교법으로 오.등 및 Kirkham, 등이 보고 한 간단한 초기 빛 경계조건에서의 해와 일치함을 확인했다. Ficks의 확산식의 해로 계산된 완만한 제염 속도를 근거로하여 담수 제염 방법별 제염 속도와 토양중 염분분포를 추정할수있는 모형식을 제시하였다.

• 한국건설순환자원학회논문집
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• 제3권1호
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• pp.22-33
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• 2015

Chloride ions in RC (Reinforced Concrete) structures can cause very severe corrosion in reinforcement steel. It is generally informed that chloride penetration can be considerably accelerated by enlarged chloride diffusion due to cracks. These cracks play a role in main routes through which chloride ions penetrate into the concrete, and also lead to steel corrosion in RC structures exposed to chloride attack, such as port and ocean structures. In this paper, field survey including evaluation of crack and chloride concentration distribution in concrete is performed to investigate an effect of crack on chloride diffusion. The service life of cracked concrete exposed to the marine environmental condition is estimated considering the crack effect on chloride diffusion. For this purpose, diffusion coefficients in cracked concrete are obtained based on the field survey. Using the relationship between diffusion coefficients in the cracked concrete and the crack widths, service life of the cracked concrete is predicted in a probabilistic framework. A bimodal distribution with two peaks, consisting of a weighted sum of two normal distributions is introduced to describe chloride diffusion of the concrete wharf with crack.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2009년도 추계 학술논문 발표대회
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• pp.127-131
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• 2009

The purpose of this study is to provide fundamental data on chloride diffusion from lightweight aggregate concrete by utilizing crushed stone-powder. Accordingly, the study performed experiments using concrete aggregates of Crushed Aggregate (CG), Single-sized Lightweight Aggregate (SLG), Continuous Graded Lightweight Aggregate (CLG), and using water-binder ratio of 0.4, 0.5, 0.6, and using binder of FA and BFS. The chloride diffusion coefficient is calculated after experiment based on NT BUILD 492. Diffusion coefficient of SLG and CLG were little bit higher than CG Concrete, but the difference is meaningless. Also, chloride diffusion coefficient indicates that it is highly affected by water-binder ratio, and it decreases with the decrease in water-binder ratio. The admixture substitution indicates decrease only with water-binder ratio of 0.4 for FA15% case, but admixture substitution indicates decrease with all levels of ratio for FA10 + BFS20% which means more appropriate. According to the analysis result of chloride diffusion from lightweight aggregate concrete, crushed stone-powder utilized lightweight aggregate concrete indicates higher chloride diffusion coefficient than CG concrete, which is not a significant difference, and can improve resistance through water-binder ratio and admixture substitution.

• 한국구조물진단유지관리공학회 논문집
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• 제19권5호
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• pp.83-91
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• 2015

콘크리트 표면의 상태에 따라 염화물은 증가 또는 감소하게 되며 이는 철근부식 및 내구수명에 매우 중요한 인자가 된다. 콘크리트의 내구성 저하를 방지하기 위해 표면함침과 같이 많은 표면강화 기술이 개발되었으나 이중 콘크리트 구조와 확산계수의 시간의존성을 고려한 염화물 해석방법은 매우 제한적이다. 본 논문에서는 표면 강화된 이중구조 콘크리트에 대해 시간의존성 확산계수를 도입하여 염화물 해석기법을 제안하였으며, 역해석을 통하여 기존의 실험결과와 비교하였다. 2년간 비말대, 해수중, 조석대 상태에 노출된 표면 함침된 콘크리트 시편에 대해 표면염화물량과 확산계수를 도출하고 Life-365에서 제안한 확산계수 식과 비교 분석하였다. 시간의존성을 고려한 결과 비말대 시편의 오차는 0.28에서 0.20 수준으로, 조석대 시편은 0.29에서 0.11 수준으로, 해수중에서는 0.54에서 0.40 수준으로 오차가 감소함을 알 수 있었다. 또한 Life365에서 사용되는 확산계수식을 사용할 경우, 과다한 확산계수로 인해 상대오차가 커지고 높은 침투깊이(e)와 낮은 확산계수비($D_1/D_2$)를 필요로 함을 알 수 있다.