• 한국응용과학기술학회지
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• 제31권3호
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• pp.402-407
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• 2014

Herein, we describe the effect of the cooling-off condition of a solution-processed 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS-pentacene) film on its molecular distribution and the resultant electrical properties. Since the solvent in a TIPS-pentacene droplet gradually evaporates from the rim to the center exhibiting a radial form of solute, for a quenched case, domains of the TIPS-pentacene film are aboriginally spread showing original features of radial shape due to suppressed molecular rearrangement during the momentary cooling period. For the slowly cooled case, however, TIPS-pentacene molecules are randomly rearranged during the long cooling period. As a result, in the lopsided electrodes structure proposed in this work, the charge transport generates more effectively under the case for radial distribution induced by the quenching technique. It was found that the molecular redistribution during the cooling-period plays an important role on the magnitude of the mobility in a solution-processed organic transistor. This work provides at least a scientific basis between the molecular distribution and electrical properties in solution-processed organic devices.

• Membrane and Water Treatment
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• 제14권2호
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• pp.95-106
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• 2023

In the developing country like India, groundwater is the main sources for household, irrigation and industrial use. Its contamination poses hydro-geological and environmental concern. The hazardous waste sites such as landfills can lead to contamination of ground water. The contaminants existing at such sites can eventually find ingress down through the soil and into the groundwater in case of leakage. It is necessary to understand the process of migration of pollutants through sub-surface porous medium for avoiding health risks. On this backdrop, the present paper investigates the behavior of pollutants' migration through porous media. The laboratory experiments were carried out on a soil-column model that represents porous media. Two different types of soils (standard sand and red soil) were considered as the media. Further, two different solutes, i.e., non-reactive and reactive, were used. The experimental results are simulated through numerical modeling. The percentage variation in the experimental and numerical results is found to be in the range of 0.75- 11.23 % and 0.84 - 1.26% in case of standard sand and red soil, respectively. While a close agreement is observed in most of the breakthrough curves obtained experimentally and numerically, good agreement is seen in either result in one case.

• Asian-Australasian Journal of Animal Sciences
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• 제30권5호
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• pp.643-652
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• 2017

Objective: Prostaglandins (PGs) function in various reproductive processes, including luteolysis, maternal pregnancy recognition, conceptus development, and parturition. Our earlier study has shown that PG transporters ATP-binding cassette, subfamily C, member 4 (ABCC4) and solute carrier organic anion transporter family, member 2A1 (SLCO2A1) are expressed in the uterine endometrium in pigs. Since several other PG transporters such as ABCC1, ABCC9, SLCO4C1, and SLCO5A1 are known to be present in the uterine endometrium, this study investigated the expression of these PG transporters in the porcine uterine endometrium and placenta. Methods: Uterine endometrial tissues were obtained from gilts on day (D) 12 and D15 of the estrous cycle and days 12, 15, 30, 60, 90, and 114 of pregnancy. Results: ABCC1, ABCC9, SLCO4C1, and SLCO5A1 mRNAs were expressed in the uterine endometrium, and levels of expression changed during the estrous cycle and pregnancy. Expression of ABCC1 and ABCC9 mRNAs was localized mainly to luminal and glandular epithelial cells in the uterine endometrium, and chorionic epithelial cells during pregnancy. Conceptuses during early pregnancy and chorioallantoic tissues from mid to late pregnancy also expressed these PG transporters. $Estradiol-17{\beta}$ increased the expression of ABCC1 and SLCO5A1, but not ABCC9 and SLCO4C1 mRNAs and increasing doses of $interleukin-1{\beta}$ induced the expression of ABCC9, SLCO4C1, and SLCO5A1 mRNAs in endometrial explant tissues. Conclusion: These data showed that several PG transporters such as ABCC1, ABCC9, SLCO4C1, and SLCO5A1 were expressed at the maternal-conceptus interface, suggesting that these PG transporters may play an important role in the establishment and maintenance of pregnancy by regulating PG transport in the uterine endometrium and placenta in pigs.

• 지질공학
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• 제19권1호
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• pp.81-88
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• 2009

물리 화학적 불균질 특성을 가진 매질 중 K 임의장과 $K_d$ 임의장이 정(+)의 상관관계를 가지는 경우, 매질 내 이송되는 오염운이 보이는 적률변화를 알아보기 위해 등방매질 내 이송되는 비반응성 오염운에 대한 2차원 몬테카를로 시뮬레이션이 시행되었다. 흡착성이 증가함에 따라 변화하는 이차적률들을 관찰하기 위해 1, 2, 5의 지연요소가 설정되었다. 지연된 종이차공간적률, ${Z_{11}}^{'R}(t',l')$은 오염운의 이송이 진행됨에 따라 증가하며 초기 오염운의 크기가 증가함에 따라 증가한다. 또한 지연요소가 증가함에 따라 감소하며, 일차분석해에 의한 이론적 결과와 비교적 잘 일치함을 보인다. 지연된 종오염운중심분산, ${Z_{11}}^{'R}(t',l')$은 초기오염원의 크기, $l_2'$가 증가할수록 감소하며 설정된 시뮬레이션에 의해서는 아직 에르고딕 이송상태에 도달하지 않았음을 지시해준다. 지연요소가 증가함에 따라 현저히 감소하여 오염운 중심점에 대한 불확실성이 감소함을 보인다. 지연된 단일입자종이송분산, ${X_{11}}^{'R}(t')$은 세 가지 다른 등급의 지연요소에 대해서 모두 일차근사법에 의한 이론적 결과와 비교적 잘 일치한다. 따라서 종방향의 지연된 이차적률들은 추계론적 시뮬레이션에 의해 산출될 수 있으며, 일차근사법에 의한 분석해는 종방향의 지연된 적률들에 대해 상당히 정확한 근사값을 제공하고 있음을 결론지을 수 있다.

• 수산해양기술연구
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• 제33권1호
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• pp.9-26
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• 1997

Stokes drift(SD) and Lagrangian discharge(LD) are important factors for analysis of flushing time, tidal exchange, solute transport and pollutant dispersion. The factors should be calculated using the approached method to flow phenomena. The aim of this paper re-examines the previous procedures for computing the SD and LD, and is to propose the new method approached to stratified flow field in the cross-section of coastal region, e.g. Masan Bay. The intensity of velocity near the bottom boundary layer(BBL) depends on the sea-bed irregularity in the coastal estuaries. So we calculated the depth mean velocity(DMV) considering that of BBL omitted in Kjerfve's calculation method. It revealed that BBL effect resulting in application of the bay acts largely on DMV in half more among 1l stations. The new expression of SD and LD per unit width in the cross-section using the developed DMV and proposed decomposition procedure of current were derived as follow : $$Q=u_0+\frac{1}{2}H_1{U_1cos(\varphi_h-\varphi_u)+U_3cos(\varphi_h-\varphi{ud})} LD ED SD$(Q_{skim}+Q_{sk2}) The third term, $Q_{sk2}$, on the right-hand of the equation is showed newly and arise from vertical oscillatory shear. According to the results applied in 3 cross-sections including 11 stations of the bay, the volume difference between proposed and previous SD was founded to be almost 2 times more at some stations. But their mean transport volumes over all stations are 18% less than the previous SD. Among two terms of SD, the flux of second term, $Q_{skim}$, is larger than third term, $Q_{sk2}$, in the main channel of cross-section, so that $Q_{skim}$ has a strong dependence on the tidal pumping, whereas third term is larger than second in the marginal channel. It means that $Q_{sk2}$ has trapping or shear effect more than tidal pumping phenomena. Maximum range of the fluctuation in LD is 40% as compared with the previous equations, but mean range of it is showed 11% at all stations, namely, small change. It mean that two components of SD interact as compensating flow. Therefore, the computation of SD and LD depend on decomposition procedure of velocity component in obtaining the volume transport of temporal and spacial flow through channels. The calculation of SD and LD proposed here can separate the shear effect from the previous SD component, so can be applied to non-uniform flow condition of cross-section, namely, baroclinic flow field.

• The Korean Journal of Ecology
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• 제28권4호
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• pp.181-188
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• 2005

Methods used to study carbon sequestration by soil aggregates have often excluded the concentric spatial variability and other dynamic processes that contribute to resource accessibility and solute transport within aggregates. We investigated the spatial gradients of carbon (C) and nitrogen (N) from the exterior to interior layers within macroaggregates, $6.3\sim9.5$ mm, sampled from conventional tillage (CT) and no tillage (NT) sites of a Hoytville silt clay loam. Spatial gradients in C accumulation within macroaggregates were related to the differences in C dynamics by determining the sizes and the turnover rates of fast C and slow C pools in the concentric layers of aggregates. Aggregate exteriors contained more labile C and were characterized by greater C mineralization rates than their interiors in both management systems. In contrast, C in the interior layers of aggregates was more resistant in both systems. These results indicated the spatial differentiation of C dynamics within macroaggregates, i.e., exterior layers as a reactive site and interior layers as a protective site. Greater total C distribution in the exterior layers of NT aggregates indicated more influx of C from the macropores in interaggregate space than C. mineralization (net gain of C), whereas lower C distribution within the exterior layers of CT aggregates indicated net loss of C by greater C mineralization than C influx. We found total C increased approximately 1.6-fold by the conversion of CT soils to NT management systems for a period of 36 years. Differences in total accumulation and the spatial distribution of C within aggregates affected by management were attributed to the differences in aggregate stability and pore networks controlling the spatial heterogeneities of resource availability and microbial activity within aggregates.

• 자원환경지질
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• 제42권6호
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• pp.609-618
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• 2009

지층 내에 발달한 고투수성 단층은 유체, 에너지, 그리고 용질이 이동하는데 있어서 중요한 역할을 하는 지질구조이다. 따라서 고투수성 단층 주변부에서는 지열수(혹은 온천), 지열 이상대, 그리고 금속 광상 등이 형성될 가능성이 크다. 단층의 구조에 따른 지하수 유동과 이에 따른 지층 내의 열적 상태를 확인하기 위해서 단층 구조가 다른 세 가지의 경우에 대해서 이차원 열-수리적 거동 모델링을 수행하였다. 모델링 결과로부터 세 가지 모든 단층 구조의 경우에서 단층의 투수율이 커지면 단층대에서의 지하수 용출 온도가 초기 온도 보다 높아지는 경향을 확인 할 수 있다. Peclet number 와 단층대에서의 용출온도의 상관관계 분석으로부터 상관계수($R^2$)가 0.98로 상당히 높은 것을 확인하였다. Peclet number가 1이상 일 때 단층대에서는 약 $32^{\circ}C$ 이상의 온도가 용출되며 이러한 경우에 단층대에서의 열흐름은 매질을 통한 전도 보다는 지하수에 의한 대류의 영향이 큰 것으로 판단된다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2008년도 학술발표회 논문집
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• pp.2046-2050
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• 2008

현재까지 우리나라에서 주로 사용되고 있는 2차원 흐름 해석 모형은 미연방 도로국(U.S. Federal Highway Administration)과 연계하여 Brigham Young University에서 개발된 SMS(Surface-Water Modeling System)모형이다. SMS모형 중 이송 확산 모형으로는 RMA-4가 포함되나 이 모형은 최신 수치기법을 반영하지 못하는 등의 문제점들로 인해 실제 물리적 현상을 모의에 있어서 한계를 가지고 있다. 따라서 물리적 현상에 대한 적절한 모의를 위해 여러 개선과정을 거쳐 RAM4가 개발되었다. 본 연구를 위해 점적분 유사량 측정기(P-61)와 대하천 유속계를 사용하여 대상구간의 SS자료 및 유속의 2차원적 분포를 취득하였고, SMS의 Pre-processing 기능을 이용하여 유한요소망을 구성하였다. 구성된 유한요소망과 흐름모형인 RMA-2를 사용하여 대상구간의 유속장을 모의하였다. 이때 모의된 유속장과 현장에서 취득한 유속분포를 비교하여 RMA-2를 검증하였고, SS자료와 RAM4로 모의된 농도장을 비교하여 RAM4를 검증하였다. 검증된 두 모형을 바탕으로 대상 구간에서 다량의 점오염원이 투입되는 가상의 시나리오를 선정 및 적용하여 오염물 이송 및 확산 거동에 대해 살펴보았다. 본 연구의 대상 하천은 형산강으로써, 유역 내에 경주시와 포항시가 위치하고 이 두 도시를 잇는 산업도로가 형산강 본류 위를 지나고, 또한 두 도시를 관류하고 있어 다른 국가하천과 마찬가지로 지속적이고 안정적인 수질관리가 필요한 하천이다, 모의구간은 형산강 본류 중 No. 68(안강 수위관측소 상류 약 350 m)에서 No. 48(부조 수위관측소 하류 약 200 m)까지로서, 약 4.3 km 구간을 모의 하였다. 모의구간 시점에서 약 0.35 km 지점에 산업도로의 일부분인 강동대교, 0.98 km 지점에 왕신천 유입, 1.35 km 지점에 수중보, 1.8 km 지점에 국당1교, 3.2 km 지점에 국당2교가 위치하며 구간 내에는 만곡 및 사행, 특히 수중보 전 후로 사주가 발달해있어 2차원 흐름 및 이송확산 모의에 적합하다고 판단되었다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제7권3호
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• pp.103-114
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• 2002

불포화토양내 물의 흐름과 유기오염물질의 이동현상을 예측하기 위해서는 불포화토양의 토양수분곡선을 구하는 것이 필수적이다. 입자크기분포로부터 토양수분곡선을 직접 구하는 물리경험적 방법이 많은 연구자들에 의해 제안되고 적용되어왔다. 이 방법은 공극크기분포가 직접적으로 입자크기분포와 상호 연관되어있다는 개념을 이용한 것으로, 입자크기분포곡선을 산정하는 방법이 토양수분곡선추정에 영향을 미칠 수 있다는 것을 의미한다. 본 연구에서는 Arya-Paris 모형을 이용한 토양수분곡선 추정이 어떠한 입자크기분포모형을 선택하는가에 따라 영향을 받는지를 알아보고자 하였다. 1∼4의 추정변수를 갖는 4개의 입자분포곡선 모형을 사용한 결과 단지 1개의 추정변수를 갖는 Jaky모형이 더 많은 추정변수를 가진 모형보다 토양수분곡선을 잘 예측하였다. Jaky모형의 우월한 예측력은 아마도 현장토양이 가지는 구조적 특성 때문인 것으로 사료된다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2010년도 춘계학술발표대회
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• pp.5.1-5.1
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• 2010

One of the most important environmental problems is global warming. Global warming is caused by increase in the amounts of water vapor, methane, carbon dioxide and other gases being released into the atmosphere as a result of the burning of fossil fuels. It has thus become important to reduce fossil fuel use. Environmentally friendly preparation of functional materials has, therefore, attracted much interest for environmental problems. Furthermore, nature mimetic processes are recently been of great interest as environmentally friendly one. There have been many studies on fabrication of various functional nanocrystals. Among various nanocrystal fabrication techniques, flux growth is an environmentally friendly, very convenient process and can produce functional nanocrystals at temperatures below the melting points of the solutes. Furthermore, this technique is suitable for the synthesis of crystals having an enhedral habit. In flux growth, the constituents of the materials to be crystallized are dissolved in a suitable flux (solvent) and crystal growth occurs as the solution becomes critically supersaturated. The supersaturation is attained by cooling the solution, by evaporation of the solvent or by a transport process in which the solute is made to flow from a hotter to a cooler region. Many kinds of oxide nanocrystals have been grown in our laboratory. For example, zero- (e.g., particle), one- (e.g., whisker and tube) and two-dimensional (e.g., sheet) nanocrystals were successfully grown by flux method. Our flux-growth technique has some industrial and ecological merits because the nanocrystal fabrication temperatures are far below their melting points and because the used reagents are less harmless to human being and the environment.