• Journal of Korea Soil Environment Society
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• v.1 no.2
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• pp.91-101
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• 1996

In recent years, phytoremediation, the use of plants to detoxify hydrocarbons, has been a promising new area of research, particularly in situ cleanup of large volumes of slightly contaminated soils. There is increasing need for a mathematical model that can be used as a predictive tool prior to actual field implementation of such a relatively new technique. Although a number of models exist for solute-plant interaction in the vegetated zone of soil, most of them have focused on ionic nutrients and some metals. In this study, we developed a mathematical model for simulation of bioremediation of hydrocarbons in soil, associated with plant root systems. The proposed model includes root interactions with soil-water and hydrocarbons in time and space, as well as advective and dispersive transport in unsaturated soil. The developed model considers gas phase diffusion and liquid-gas mass exchanges. For simulation of temporal and spatial changes in root behavior on soil-water and with hydrocarbons, time-specific distribution of root quantity through soil was incorporated into the simulation model. Hydrocarbon absorption and subsequent uptake into roots with water were simulated with empirical equations. In addition, microbial activity in the rhizosphere, a zone of unique interaction between roots and soil microorganisms, was modeled using a biofilm theory. This mathematical model for understanding and predicting fate and transport of compound in plant-aided remediation will assist effective application of plant-aided remediation to field contamination.

• Analytical Science and Technology
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• v.6 no.1
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• pp.107-119
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• 1993

The purpose of this study is to investigated the elution behavior of platinoid metal acetylacetonates, which is the key to elucidate their retention mechanism and optimize their RPLC separation conditions. The retention data of four platinoid metal acetylacetonates have been measured on four different columns in methanol-water and acetonitrile-water systems. The retention of uncharged platinoid metal acetylacetonates is interpreted by solvophobic effect. The retention of platinoid metal acetylacetonates is also greatly influenced by the geometric structure of the complexes. The square planar chelates, $Pd(acac)_2$, $Pt(acac)_2$, are retained longer than the octahedral chelates, $Rh(acac)_3$, $Ir(acac)_3$. It is likely due to that square planar chelates show greater interaction with nonpolar stationary phase than octahedral chelates. The results of van't Hoff plots have shown that platinoid metal acetylacetonates is operated on the same retention mechanism in the temperature range of $25{\sim}45^{\circ}C$. The study of the retention mechanism by the enthalpy-entropy compensation phenomenon has indicated that the retention mechanism of octahedral chelates and square planar chelates do not vary with the composition change of methanol-water mobile phase, respectively. In acetonitrile-water mobile phase, however, the retention mechanism is observed to be more complicated. Optimum condition for the separation of four platinoid metal acetylacetonates is found to be 40% methanol, polymeric C18 column, and $45^{\circ}C$.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2000.04a
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• pp.12-13
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• 2000

최근 플라스틱제 식품 포장재에 대한 환경학적 문제가 제기됨으로 인하여 다양한 곡류 단백질의 필름 형성능력에 많은 관심이 모아지고 있다. 단백질 필름으로서 soy protein, wheat gluten, rice bran, corn zein, glatin 및 colloagen 등의 소재들이 많은 관심을 모으고 있으며, 비교적 필름 형성력이 뛰어나고, 저렴한 가격으로 구입할 수 있는 대두 단백질에 커다란 관심이 모아지고 있는 실정이다. 이들 물질로부터 제조된 가식성 필름 및 코팅제들은 식품의 보존기간을 연장시킬 뿐만 아니라 수분 및 용질의 이동을 방지하여 식품의 품질을 개선시킬 수 있다. 또한 이들 필름 및 코팅제들은 산소 및 이산화탄소의 이동, 이로 인한 지방 산화 그리고 휘발성 향기성분들의 감소 등을 조절할 수 있다. 대두 단백질 필름의 사과 코팅제로서의 이용은 개별적 포장이 용이하지 않는 제품들의 코팅제로서 활용하여 대두 단백질 필름 및 코팅제의 잠재적 시장성을 확인하는 하나의 응용분야이다. 본 실험의 목적은 대두 단백질 코팅제를 후지와 golden delicious 사과에 코팅하여 상온 (22$^{\circ}C$)과 냉장온도(2-4$^{\circ}C$)에서 60일동안 보관하여 색도, 경도 및 산도 변화 등을 측정하여 저장 중 사과의 품질에 미치는 영향을 조사하였다. 대두 단백질 코팅제는 대두 단백 용액들 (5g, 8g, 10g/100mL water)에 glycerin (50% w/w의 단백질)을 가소재로 첨가한 후 알칼리 용액으로 pH 9.0에 맞추었다. 그런후 85$^{\circ}C$에서 30분간 가열하여 코팅제를 준비하였다. 후지 사과(붉은색)와 golden delicious 사과 (초록색)를 dipping 방법으로 코팅하여 60일도안 실온과 냉장온도에 저자하여 보존기간의 연장을 확인하였다. 사과품질의 결정인자는 Hunter L, a, b 색도값과 사과의 조직의 강도 (외부 및 내부) 그리고 산도 등을 측정하였다. 코팅된 후지 및 golden delicious 사과의 표피 및 내부 경도는 control과 비교하여 높은 경도를 유지하였다. 또한 냉장온도에서 30일 동안 보관하였을 때, control 사과와 거의 비슷한 경도를 유지하였다. 식품의 색도를 소비자의 기호를 결정하는 중요한 인자이다. 대두 단백질로 코팅된 후지 사과는 상온에서 20일 동안은 control에 비하여 약간의 색도의 증가를 보였으나, 그 후 60일 동안은 색도의 증가를 보이지 않았다. 그러나 냉장 보관한 control 후지 사과에 비하여 색도의 증가가 관찰되었다. 대두 단백질 코팅제가 사과의 색도 변화를 방지하는 효과를 가졌으나, 저장 온도가 색도의 변화에 더욱 큰 영향을 미침을 알 수 있었다. 대두 단백질로 코팅된 golden delicious는 상온에서60일 동안 보관하였을 경우, 사과표피의 색도 변화를 현저히 지연시킴을 확인하였다. 또한 control과 비교하여 성공적으로 사과에 코팅하였으며, 상온에서 보관하여을 때 사과의 품질을 30일 이상 연장하는 효과를 관찰하였다. 이들 결과로부터 대두단백질 필름이 과일 등의 포장제로서 이용할 가능성을 확인하였다.

• Journal of Sericultural and Entomological Science
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• v.24 no.2
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• pp.43-54
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• 1983

In a field trial, the influence was studied by measurement of growth and leaf yields and chemical composition (in organic cations and anions and total nitrogen) with two nitrogen dressings (lower nitrogen treatment 25kg and higher nitrogen treatment 75kg urea/10a as the summer fertilizer) after the summer cutting. The results were as follows; 1. With increasingn nitrogen dressing, branch length and weight were enchanced. The fresh weight of leaves was higher to be 273.6kg/10a in the higher nitrogen treatment than in the lower nitrogen treatment on 20 September. 2. The moisture content of leaves lasted above 73% until on 30 August. Afterward it decreased sharply upto 63% on 20 September. In higher nitrogen treatment it was higher about 0.1∼1.8% than in lower nitrogen treatment. The increasing nitrogen dressings combined with leaf condition led to be soft until on 10 October. 3. Dry matter weight of leaves started decreasing around on 10 September, whereas that of branches increased until around 30 September indicating that the dry matter moved to branch and root from leaves. 4. The increase in Ca$\^$2+/ content was particularly evident, whereas the K$\^$+/ and Mg$\^$2+/ decreased with growth. The Ca$\^$2+/ content was much higher in the high nitrogen treatment than in the low nitrogen treatment. 5. With rapid decrease in total nitrogen and water in the leaves around the end of August, the Ca$\^$2+/ and Cl$\^$-/ which were higher in the lower part moved up to the upper part. Whereas the K$\^$+/, H$_2$PO$_4$$\^$-/ and SO$_4$$\^$2-/ which were higher in the upper part moved down to the lower part. 6. Total nitrogen content decreased sharply 3,200me/kg DM to 2,000me/kg DM at the end of August changing the maxmium content of total nitrogen from upper to lower part in the low nitrogen treatment on 12 September and in the high nitrogen treatment on 22 September, and an apex of branches was died and fallen 10 days after respectively. 7. The sum of cation in leaves (∑C) increased from 1400me/kg DM to 1600me/kg DM with growth, wherease that of anions (∑A) was approximatly the same during the whole growing season. As the result, the ionic balance (C-A) increased from 1000me/kg DM to 1200me/kg DM. 8. ∑C, ∑A and (C-A) were higher in the high nitrogen treatment than in the low nitrogen treatment due to be much higher of Ca$\^$2+/ content and higher of NO$\^$-/$_3$, SO$\^$2-/$_4$ and H$_2$PO$_4$$\^$-/ content.

• Korean Chemical Engineering Research
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• v.53 no.6
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• pp.723-729
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• 2015

The moment analysis of cyclic adenosine monophosphate (cAMP) was performed using chromatograms that were obtained with the pulse input method from an octadecyl silica (ODS) high-performance liquid chromatography (HPLC) column. The general rate (GR) model was employed to calculate the first absolute moment and the second central moment. Three important coefficients for moment analysis, which are molecular diffusivity ($D_m$), external mass transfer coefficient ($k_f$), and intra-particle diffusivity ($D_e$), were estimated by the Wilke-Chang equation, Wilson-Geankoplis equation, and comparing van Deemter equation to theoretical plate number equation, respectively. Experiments were conducted by various conditions of flow rates, methanol volume ratio of the mobile phase, and solute concentration. After the moment analysis, results were organized by van Deemter plots. Also van Deemter coefficients were compared each other to effect $H_{ax}$, $H_f$, and $H_d$ on height equivalent to a theoretical plate (HETP, $H_{total}$). The value of intraparticle diffusion ($H_d$) was the primary factor which makes for HETP whereas external mass transfer ($H_f$) was disregardable factor.

• Journal of the Microelectronics and Packaging Society
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• v.13 no.1 s.38
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• pp.37-42
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• 2006

The preparation and processing of PVP-gate insulators on the device performance have been studied in the fabrication of organic thin film transistors (OTFTs). One of polyvinyl series, poly-4-vinyl phenol(PVP) was used as a solute and propyleneglycol monomethyl etheracetate(PGMEA) as a solvent in the formation of organic gate solutions. The cross-linking of organic insulators was also attempted by adding the thermosetting material, poly (melamine-co-formaldehyde) as a hardener in the compounds. From the measurements of electrical insulating characteristics of metal-insulator-metal (MIM) samples, PVP-based insulating layers showed lower leakage current according to the increase of concentration of PVP and poly (melamine-co-formaldehyde) to PGMEA in the formation of organic solutions. The PVP(20 wt%) copolymer with composition of 20 wt% PVP to PGMEA and cross-linked PVPs in which 5 wt% and 10 wt% poly (melamine-co-formaldehyde) hardeners had been additional]y mixed into PVP(20 wt%) copolymers were used as gate dielectrics in the fabrication of OTFTs, respectively. In our experiments, the maximum field effect mobility of $0.31cm^2/Vs$ could be obtained in the 5 wt% cross-linked PVP(20 wt%) device and the highest on/off current ratio of $1.92{\times}10^5$ in the 10 wt% cross-linked PVP(20 wt%) device.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.172.2-173
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• 2003

단백질, 탄수화물, 유지 등과 같은 생고분자를 소재로하여 제조하는 가식성 또는 생분해성 필름은 식품표면을 코팅하거나, 식품의 내부에 사용하여 식품을 외부의 충격으로부터 보호하고 식품의 저장수명을 증가시키는 동시에 수분, 기체 및 용질의 이동을 방지하는 기능을 한다. 이러한 가식성 필름의 소재 중 하나인 전분은 비교적 저가의 재료이고 기체투과를 방지하는 성질은 우수하지만, 탄력성이 적은 단점을 가지고 있다. 생고분자필름의 물리적 강도를 증진시키고 수증기의 투과성을 낮추는 방법으로 단백질과 탄수화물을 복합적으로 사용한다 본 실험에서는 분리 대두 단백질(SPI)과 옥수수 전분을 혼합하여 가식성의 생분해성 필름을 제조하고 이들의 이화학적 특성에 대해 연구하였다. SPI 필름은 SPI 5g에 증류수 100$m\ell$을 가해 glycerol 2g을 첨가해 제조하였으며, 옥수수 전분필름은 옥수수 전분 6g에 증류수 100$m\ell$을 가해 glycerol 1.2g을 첨가해 제조하였다. SPI와 옥수수 전분의 혼합필름은 SPI와 옥수수 전분의 양을 1：1 비율로 혼합하여 제조하였다. SPI 필름, 옥수수 전분 및 SPI와 옥수수 전분 용액의 혼합필름의 각각의 수증기 투과도는 7.49$\times$$10^{-11}$, 2.69$\times$$10^{-11}$, 4.24$\times$$10^{-11}$ g.m/m$^2$.s.Pa이었다. 본 실험으로 SPI의 단일재료로만 필름을 제조하였을 때보다 SPI 용액에 옥수수 전분용액을 혼합해 필름을 제조하면 탄력성을 유지하면서 수증기 투과도를 낮출 수 있다는 결과를 얻을 수 있었다.현미밥의 유리아미노산 분석 결과 필수아미노산을 포함한 다량의 아미노산이 존재하였으며 혈압강하 기능성 성분인 GABA(${\gamma}$ -amino butyric acid) 함량은 현미가 4.7 mg/100 g, 발아현미 20.8 mg/100 g이었으며, 동결건조 후 분석한 발아현미밥의 GABA 함량은 5.7 mg/100 g이었다. 발아현미밥의 관능검사 결과는 색, 윤기, 맛, 부착성, 응집성, 탄력성이 A가 유의적으로 높았으며, 외관의 경우도 A가 더 높은 평가를 받았다. 또한 전반적으로 A가 B에 비해 유의적인 차이를 나타내진 않았지만 더 나은 선호도를 나타내었다.좋게 평가되었다.＊값은 63-68사이로, a＊값은 0.13에서 -0.89사이를 b＊값은 2-5값 사이에서 변화하여 제조한 죽의 색이 옅은 황색임을 알 수 있었다. 고형분 함량, 퍼짐성과 pH에 대한 $R^2$은 각각 0.4280, 0.5433과 0.2406임을 볼 때 버섯, 당근, 대파의 비율에 따라 제조한 쇠고기 야채 쌀죽의 고형분 함량, 퍼짐성과 pH는 설정된 범위내에서 그 유의성이 인정되지 않아 큰 영향을 미치지 않음을 알 수 있었다. 관능검사 결과, 색과 향에 대한 반응표면 회귀식의 $R^2$은 각각0.6000과 0.7825이고 P-value는 각각 0.4290과 0.0942로서 5% 수준에서 유의한 상관성이 없음을 확인할 수 있었다. 맛과 점성에 대한 $R^2$은 0.8717과 0.8068이고 P-value는 각각 0.0195 (p ＜0.05)와 0.0612로서 야채의 배합비에 따라 맛에 있어서 유의확률 5%수준에서 그 유의성이 인정되었으며, 전체적인 기호도에 대한 유의성은 $R^2$이 0.8463이고 P-value는 0.034

• Journal of the Korean Society of Groundwater Environment
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• v.6 no.3
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• pp.111-119
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• 1999

The purpose of this study is the simulation of discontinuous rockmass and identification of characteristics of discontinuity network as a branch of the study on characteristics of groundwater system in discontinuous rockmass for evaluation of safety on disposal site of radioactive waste. In this study the site for LPG underground storage was selected for the similarities of the conditions which were required for disposal site of radioactive waste. Through the identification of hydraulic properties. characteristics of discontinuities and selection of discontinuity model around LPG underground storage facility. the applications of discrete fracture network model were evaluated for the analysis of pathway. The orientation and spatial density of discontinuities are primarily important elements for the simulation of groundwater and solute transportation in discrete fracture network model. In this study three fracture sets identified and the spatial intensity (P$_{32}$) of discontinuities is revealed as 0.85 $m^2$/㎥. The conductive fracture intensity (P$_{32c}$) estimated for the simulation area around propane cavern (200${\times}$200${\times}$200) is 0.536 $m^2$/㎥. Truncated conductive fracture intensity (T-P$_{32c}$) is calculated as 0.26 $m^2$/㎥ by eliminating the fracture with the iowest transmissivity and based on this value the pathway from the water curtain to PC 2. PC 3 analyzed.

• Korean Journal of Materials Research
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• v.11 no.2
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• pp.104-114
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• 2001

To investigate the effects of the addition of Nb and Sn on the recrystallization of Zr- Sn-Nb alloys, both Vickers micro-hardness test and TEP measurement were carried out on cold-worked specimens annealed at various temperatures from $300^{\circ}C$ to 75$0^{\circ}C$. The microstructures of heat treated specimens were analyzed by optical microscope, SEM, and TEM. The study of microhardness and microstructures showed that both recrystallization process and grain growth were retarded as the activation energy was increased by the addition of Nb and Sn. Especially, the addition of Sn was more effective on retarding recrystallization. Precipitates were formed more easily when Nb was added because the solubility of Nb into Zr is lower than that of Sn. However, the recrystallization process was affected more by Sn than Nb because the strain field formed by substitutional Sn repressed the dislocation movement. TEP was increased due to the decrease of electron scattering as recovery and recrystallization were proceeded and saturated when the recrystallization completed. However, when precipitates formed, TEP was increased because the decrease of solute concentration near the precipitates caused the decrease of electron scattering.

• Journal of Soil and Groundwater Environment
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• v.10 no.6
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• pp.20-31
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• 2005

Three dimensional Monte-Carlo simulations of non-ergodic transport of a lion-reactive solute plume by steady-state groundwater flow under a uniform mean velocity in isotropic heterogeneous aquifers were conducted. The log-normally distributed hydraulic conductivity, K(x), is modeled as a random field. Significant efforts are made to reduce tile simulation uncertainties. Ensemble averages of the second spatial moments of the plume and plume centroid variances were simulated with 1600 Monte Carlo runs for three variances of log K, ${\sigma}_Y^2=0.09,\;0.23$, and 0.46, and three dimensionless lengths of line plume sources normal to the mean velocity. The simulated second spatial moment and the plume centroid variance in longitudinal direction fit well to the first order theoretical results while the simulated transverse moments are generally larger than the first order results. The first order theoretical results significantly underestimated the simulated dimensionless transverse moments for the aquifers of large ${\sigma}_Y^2$ and large dimensionless time. The ergodic condition for the second spatial moments is far from reaching in all cases simulated, and transport In transverse directions may reach ergodic condition much slower than that in longitudinal direction. The evolution of the contaminant transported in a heterogeneous aquifer is not affected by the shape of the initial plume but affected mainly by the degree of the heterogeneity and the size of the initial plume.