• 한국지반환경공학회 논문집
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• 제9권5호
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• pp.83-89
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• 2008

본 연구에서는 산사태 발생시 토석류 확산(퍼짐) 형태 및 흐름 속도를 알아내기 위하여 실내 모형 산사태 흐름장치를 구성하고 주문진 표준사를 이용하여 함수비에 따라 산사태를 발생시켜 산사태의 확산(퍼짐) 범위와 흐름 속도를 측정하였다. 산사태 흐름시험 결과에서 함수비가 높을수록 확산 범위가 넓게 퍼졌고 확산 속도 또한 빠르게 기록되었다. 함수비별로 기록된 값의 평균을 구하여 분석한 결과 함수비에 비례하여 산사태의 확산 범위와 속도가 비례적으로 증가함을 알 수 있었다. 일반적으로 확산(범위) 형태는 부채꼴 모양으로 나타났으며, 함수비가 높아짐에 따라 확산 속도가 빠르게 나타났고, 확산 속도가 빠를수록 확산 폭이 좁으면서 길게 퍼지는 형태로 나타났다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 봄 학술발표회 논문집(I)
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• pp.303-308
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• 1998

In the concrete structures exposed to environmental conditions at early ages, water movement occurs by moisture diffusion in the concrete, and self-desiccation of concrete is also occurred. Thus the internal relative humidity is changed from moisture diffusion and self-desiccation. Thus the internal relative humidity at each location in concrete includes the decrease by self-desiccation. Especially, for high-strength concrete the much unit cement content is used, so that the non-uniform relative humidity distribution is affected form self-desiccation at early ages. In this study, the internal relative humidity in concrete was measured at early ages, and the moisture diffusion component and self-desiccation component of total relative humidity were discussed.

• 마이크로전자및패키징학회지
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• 제18권2호
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• pp.11-15
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• 2011

폴리머의 흡습문제를 해석하기 위해 흡습확산 지배방정식과 열전달 방정식을 고찰하였다. 두 방정식의 동일 한 형식의 편미분방정식이기 때문에 상사의 법칙을 적용하여 물체가 등온 하중조건을 받고 있을 때 단일 매질의 확산문 제를 상용유한요소코드에 의해 수치적으로 해석하였다. 여러 소재로 구성된 매체는 흡습질량이 접착면에서 불연속 특성 을 갖기 때문에 확산해석에 상사법칙을 직접적으로 적용할 수 없으나 흡습관련 소재 특성이 온도만의 함수인 소재로 구 성된 매체에서 흡습확산 문제는 접착면에서 연속성을 가지고 있는 압력비를 고려함으로써 해석하였다. 실리콘-비전도성 수지 접합체의 측정된 흡습 변화량은 접합면을 경계조건으로 하고 단일 매체에 대한 해석 결과와 매우 근접한 결과를 보였으나, 복합체로 해석한 결과는 흡습시간이 경과할수록 점점 큰 오차가 발생하였다.

• Current Research on Agriculture and Life Sciences
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• 제10권
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• pp.41-47
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• 1992

목재투습성에 관하여 다음과 같은 결과가 밝혀졌다. 1) 시편두께 0mm에 외삽한 투습저항값이 정(正)이므로 목재표면에서의 수분전달현상을 고려함이 인정되었다. 2) 목재내부의 함수율분포는 함수율 9%를 경계로 두 개의 직선으로 나타났다. 또 시편양측의 공기중 평형함수율이 9%이상일 때는 한 개의 직선으로 나타났다. 수분확산계수는 함수율 9%를 경계로 두 개의 일정한 값을 가지며, 이 값들은 오직 함수율에만 관계한다. 4) 수분이동량은 목재내의 함수율구배에 의존한다. 4) 목재의 수분전달계수는 시편두께에 의존하였다. 이 현상의 기구에 대해서는 아직 알 수 없다.

• 호남수학학술지
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• 제32권2호
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• pp.193-202
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• 2010

We investigate the estimation of the moisture transfer coefficients in porous media by optimization technique which minimizes the functional defined by the squares error of the numerical solution of an inverse diffusion problem from their experimental values of the moisture content at the some time-steps. In this paper, we solve a diffusion equation numerically by the control volume finite element methods.

• 한국가구학회지
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• 제20권6호
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• pp.599-604
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• 2009

For the search of unified law of moisture movement in wood, moisture distribution of Korean red pine at non-steady state was investigated. We assume that the equilibrium moisture content (EMC) in wood depends on only temperature and relative humidity, it can be control in temperature and humidity chamber. If temperature is constant and humidity or vapor pressure is changed with sin curve shape at adequate cycles, EMC in chamber can be changed as well with sin-curve shape. The setup condition of a non-steady state in humidity control chambers is a constant temperature at $20^{\circ}C$ and 15+10 sin ${\omega}t$ percent EMC. It can be found that the distribution of moisture in the specimen with varying relative humidity are illustrated various types. Moisture in wood is complicated and vibrates with the moisture sorption process. Considering a unified law of moisture movement in wood, it is considered that the most important fact is to search the method of precise diffusion & transfer coefficients.

• Computers and Concrete
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• 제13권3호
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• pp.361-375
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• 2014

The moisture transport in underground concrete was experimentally investigated and the nonlinear model of moisture transport considering the effects of water diffusion, hydration of cementicious materials and water permeability was proposed. The consumed moisture content by self-desiccation could be firstly calculated according to evolved hydration degree of cement and mineral admixtures. Furthermore, the finite differential method was adopted to solve the moisture transport model by linearizing the nonlinear moisture diffusion coefficient. The comparison between experimental and calculated results showed a good agreement, which indicated that the proposed moisture model could be used to predict moisture content evolution in underground concrete members with drying-wetting boundaries.

• 반도체디스플레이기술학회지
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• 제12권1호
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• pp.23-28
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• 2013

Epoxy resins are widely used in microelectronics packaging such as printed circuit board and encapsulating for semiconductor manufacturing. Water can diffuse into and through the epoxy matrix systems and moisture absorption at boarding interfaces of matrix resin systems can lead to a hydrolysis at the interfaces resulting in delamination of encapsulating materials. In the study, the changes of diffusion coefficient and moisture content ratio of epoxy resin systems with nano-sized fillers according to the change of liquid type epoxy resins were investigated. RE-304S, RE-310S, RE-810NM and HP-4032D as a epoxy resin, Kayahard AA as a hardener, and 1B2MI as a catalyst were used in these epoxy resin systems. After curing, moisture content ratios were measured with time under the 85 and 85% relative humidity condition using a thermo-hydrostat. The maximum moisture absorption ratio and diffusion coefficient of EMC decrease with the filler content. It can be seen that these decreases are due to the increase of filler surface area and the decrease of moisture through channel with the content of nano-sized filler.

• 한국작물학회지
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• 제49권1호
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• pp.46-51
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• 2004

The film coated snap bean (Phaseolus vulgaris) seeds with five different coating materials treated with 3% increase in seed weight were planted at sandy loam soil controlled moisture content of 18, 19, 20 and 21 %. The oxygen diffusion rate (ODR) was calculated from the different moisture content soil. The number of normal seedlings, seedling vigor, and seedling capability in field (seed vigor x dry matter weight) were observed at 9 days after planting and compared to the changes of ODR. The germination rate and ODR were sharply decreased simultaneously in the seeds planted at 21 % soil moisture content. Seedling emergence did not occur at all as the soil moisture content increased above 22 %. Hence this value should be considered as the threshold of soil moisture content for seedling emergence. An ODR value under 20% did not influence the percent emergence significantly. The certain difference observing in the emergence at the same ODR was not related clearly to the condition of soil. So it can be assumed that the limit of soil moisture content for the emergence of snap bean was approximately 20%. The value of 18% soil moisture content may be considered as the optimum for snap bean emergence. There was close relationship between the mean value of ODR in different soil moisture contents and the emergence. The germination rates of the seeds coated with the different materials were quite different when the seeds were planted at 21 % soil moisture. Dry weight of the seedlings from film coated seeds was decreased slightly, but the germination rates were not much different from the non-treated control under relatively higher soil moisture content (21 %). Major factor lowering emergence rate was oxygen stress while film coating act as a minor constraint for snap bean sown in excess soil moisture condition.

• Journal of the Korean Wood Science and Technology
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• 제20권4호
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• pp.21-30
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• 1992

An activation energy equation for moisture diffusion in wood was developed with an assumption that activation energy is directly proportional to wood specific gravity. Theoretical activation energies obtained from the activation energy equation were revealed to be always lower than actual activation energies, which implies that activation energy isn't affected only by wood specific gravity. The other affecting factors are possibly anatomical structures of wood which determine a ratio of vapor diffusion to bound water diffusion in wood. For the convenience of estimating actual activation energy by using the activation energy equation, thirteen kinds of species were categorized into three groups according to their anatomical structures.