• 한국분무공학회지
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• 제20권4호
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• pp.261-267
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• 2015

The main purpose of this study is to provide the information of soot generation of toluene fuel droplet. To achieve this, this paper provides the experimental results on the different initial diameter of toluene droplet combustion characteristics conducted under equivalent ambient pressure ($P_{amb}$) and oxygen concentration ($O_2$) conditions. Visualization of single fuel droplet was performed with high resolution CCD camera and visualization system. At the same time, ambient pressure ($P_{amb}$) and oxygen concentration ($O_2$) were maintained by ambient condition control system. Soot volume fraction ($f_v$) was analyzed and compared on the basis of intensity ratio ($I/I_0$) of background image. The result of soot generation was almost the same regardless of initial droplet diameter since thermophoretic flux is not much changed under the same ambient conditions. Soot standoff ratio (SSR) of 2 mm diameter showed unstable variation characteristics due to the short available measuring time.

• Archives of Pharmacal Research
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• 제9권2호
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• pp.87-91
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• 1986

In attempt to develop a drug delivery system using serum albumin microspheres, bovine serum albumin microspheres containing antitumar agent. Cytarabine, were prepared. The shape, surface characteristics, size distribution, behavior of in vivo distribution, drug release behavior, and degradation of albumin microsphers in animal liver issue homogenate and proteolytic enzyme were investigated. The shape of albumin microspheres was spherical and the surface was smooth and compact. The size distribution of the albumin microspheres was effected by dispertion forces during emulsification and albumin concentration. Distribution of albumin microspheres after imtravenous administration in rabbit was achieved immediately. In vitro, albumin microsphere matrix was so hard that it retained most of cytarabine except initial burst during the first 10 minutes, and the level of drug release during the initial burst was affected by heating temperature, drug/albumin microsphere matrix was so hard that it retained most of cytarabine except initial burst during the first 10 minutes, and the level of drug release during the initial burst was affected by heating temperature, drug/albumin concentration ratio and size distribution. After drug release test, the morphology of albumin microspheres was not changed. Albumin microsphere matrix was degraded by the animal liver issue homogenate and proteolytic enzyme. The degree of degradation was affected by heating temperature.

• 한국지하수토양환경학회지:지하수토양환경
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• 제15권3호
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• pp.61-68
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• 2010

Phytoextraction, one type of phytoremediation processes, has been widely used in the removal of heavy metals from polluted soil. This paper reviewed literature on metal uptake by plants and characterized the metal uptake by types of metals (Zn, Cu, Pb, Cd, and As), plant species, initial metal concentrations in soil and the distribution of metals in different parts of plants. The potential of metal accumulation and transport by plants was closely related to plants species, types of metals, and initial metal concentrations in soil. The plants belonging to Brassicaceae, Solanaceae, Poaceae, and Convolvulaceae families have shown the high potential capacity of Cd accumulation. The Gentianaceae, Euphorbiaceae, and Polygonaceae families have exhibited relatively high Pb uptake potential while the Pteridaceae and Cyperaceae families have shown relatively high Zn uptake potential. The Pteridaceae family could uptake a remarkably high amount of As compared with other plant families. The potential metal accumulation per plant biomass has increased with increasing initial metal concentration in soil up to a certain level and then decreased for Cd and Zn. For As, only Pteris vittata had a linear relationship between initial concentration in soil and potential of metal uptake. However, a meaningful relationship for Pb was not found in this study. Generally, the plants having high metal uptake potential for Cd or Pb mainly accumulated the metal in their roots. However, the Euphorbiaceae family has accumulated more than 80% of Pb in shoot. Zn has evenly accumulated in roots and stems except for the plants belonging to the Polygonaceae and Rosaceae families which accumulated Zn in their leaves. The Pteridaceae family has accumulated a higher amount of As in leaves than roots. The types of metals, plant species, and initial metal concentration in soil influence the metal uptake by plants. It is important to select site-specific plant species for effective removal of metals in soil. Therefore, this study may provide useful and beneficial information on metal accumulation by plants for the in situ phytoremediation.

• The Korean Journal of Ecology
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• 제17권3호
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• pp.311-318
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• 1994

치화화 사막에서 몇 가지 식물 뿌리의 분해율과 분해 과정에 따른 질소함량의 변화를 조사하였다 (1986년 10월 ~ 1990년 4월). 뿌리의 분해는 리그닌 함량과 역상관 관계를 보였다(r=-0.84, n=5, p<0.05). 1년생 광엽초본인 Baileya multiradiata의 분해율이 가장 높았고 다년생 협엽 초본인 Panicum obtusum의 분해율이 가장 낮았다. 지역에 따른 분해율은 playa에서 가장 낮았다. Baileya multiradiata를 제외하고 모두 분해 초기에 질소의 무기화가 있은 다음 질소의 부동화가 나타났다. Baileya multirdiata의 뿌리는 분해 초기부터 질소함량이 계속 증가하는 것으로 나타났다. 다년생 협엽초본 뿌리의 리그닌 함량은 광엽초본 뿌리의 리그닌 함량보다 높았다.

• The Korean Journal of Ecology
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• 제25권1호
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• pp.41-44
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• 2002

Weight loss, N and P dynamics during decomposition of fine roots (<2mm) of alder(Alnus japonica), oak (Quercus acutissima) and pitch pine(Pinus rigida) were studied for 33 months in Kongju, Korea. After 33 months, remaining weight of fine roots of alder, oak and pitch pine was 29.2%, 47.7% and 53.4% of the initial weight, respectively. The decomposition rate constant (k) for alder, oak and pitch pine was 0.448 $yr^1$, 0.269 $yr^1$, 0.228 $yr^1$, respectively. Initial concentration of N and P in fine roots was 10.32mg/g and 0.69mg/g for alder, 6.20mg/g and 0.37mg/g for oak and 7.26mg/g and 0.44mg/g for pitch pine, respectively. Initial concentration of N and P in alder were higher than those in oak and pitch pine. After 33 months, remaining N and P in fine roots was 39.5$\%$ and 31.8$\%$ for alder, 59.4$\%$ and 57.8$\%$ for oak, 63.0$\%$ and 83.4$\%$ for pitch pine, respectively. Decomposition rate and the rate of N released from decomposing fine roots was positively correlated with the initial N concentration of the fine roots.

• 한국환경과학회지
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• 제9권2호
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• pp.151-158
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• 2000

Considerable interest has been shown in recent years towards utilizing $TiO_2$ particles as a photocatalyst in the degradation of harmful organic contaminants. In this study, photocatalytic degradation of diazinon which is extensively used as a pesticide in the agriculture field, has been investigated with UV-illuminated $TiO_2$ weight, UV wavelength, pH of the solution. Photodegradation rate increased with decreasing initial concentration of diazinon and with increasing pH of the solution. Photodegradation rate increased with increasing $TiO_2$ weight, but was nearly the same at $TiO_2$ weight of 1g/$\ell$, 2 g/$\ell$, i.e., for initial diazinon concentratin of 5 mg/$\ell$. UV wavelength affecting on the degradation rate of diazinon decreased in the order of 254 nm>312 nm> 365 nm. For $TiO_2$ weight of 1 g/$\ell$and initial diazinon concentration of 5 mg/$\ell$, the photodegradation removal of diazinon was 100% after 130 min in the case of 254 nm, but 95% in the case of 312 nm, and 84% in the case of 365nm, after 180 min. The photodegradation of diazinon followed a first order or a pseudo - first order reaction rate. For initial diazinon concentration of 5 mg/$\ell$, the rate constants(k) in UV and $TiO_2$(1 g/$\ell$)/UV system were $0.006 min^{-1} and 0.0252 min^{-1} at 254 nm, 0.0055 min^{-1} and 0.0104 min^{-1} at 312 nm, and 0.004 min^{-1}$ at 365 nm respectively.

• 한국미생물·생명공학회지
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• 제13권3호
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• pp.239-243
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• 1985

Ethanol, Acetic acid 및 Acetaldehyde를 단일 탄소원으로 하여 Candida sP. JY-5 효모의 증식특성을 batch culture를 통해 검토하였다. Ethanol상에서 이 효모의 지수적 증식기 동안의 비증식도 ($\mu$) 값은 농도가 0.5g/l 이상일 경우 그 초기 농도에 따라 변화하나 비례하지는 않았다. 최대 비증식도는 0.291$hr^{-1}$이었고 최대 증식수율은 10g/l 농도에서 61.2 %이었다. Acetic acid상에서의 비증식도는 이 기질의 초기 농도에 관계없이 일정하였으며 그 값이 0.106$hr^{-1}$. 최대 증식수율은 10g/l 농도에서 46.8%로 나타났다. 한편 Acetaldehyde 기질에서 지수적 증식기 동안의 최대 비증식도는 0. 063$hr^{-1}$이었고 최대 증식수율은 0.2g/l 농도에서 44.9%였다.

• KSBB Journal
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• 제9권5호
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• pp.443-449
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• 1994

여러 가지 조성의 PEG 20000jDx로 구성한 수성 이상계를 사용한 에탄올 추출발효실험을 통하여 K. fragilis에 의한 돼지감자 주스의 발효 특성을 초기 당농도 및 생성 알코올 농도의 함수로 규명하여 다음의 결과를 얻었다. 균체의 비증식속도 빛 에탄올 비생성속도는 PEG 및 Dx 농도가 낮을수록 증가하였다. 비증식속도는 조성에 무관하게 초기 당농도 $80g/\ell$에서 최대치를 보였고, 에탄올 비생성속도는 $120g/\ell$최대치를 보였다. 생성 알코올 농도에 의한 저해 영향은 비증식속도에 대하여 지수함수형 을, 에탄올 비생성속도에 대하여 쌍곡선함수형을 나타냈다. Dx 농도가 2.5~5% 범위에셔 PEG 농도 가 낮을수록 에탄올 저해 영향은 감소하였다. 총괄 에탄올 생산성은 초기 당농도가 증가할수록 높았으 며 생산성이 최대치에 도랄하는 소요시간도 당농도가 증가함에 따라 증가하였다. 시간별 에탄올 생산 속도는 초기 당농도 $160g/\ell$ 에서 가장 높은 값을 보 였다. 총괄 에탄올 생산성은 대조실험에 비하여 수 성이상계 추출발효를 통하여 1.2배 이상 증가하였고 초기 당농도가 높을수록 이상계 추출발효가 더욱 유리한 것으로 나타났다.

• 한국식품영양과학회지
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• 제24권2호
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• pp.214-218
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• 1995

Elimination of residual captan during the storage and cooking process was investigated. The concentration of residual captan after sticking and drying fo captan on spinach was 2.938ppm. During storage of 5, 10, 15 and 20 days at 15$^{\circ}C$, the amount of residual captan decreased to 73.18, 80.80, 89.99 and 98.40% of the initial amount, respectively. When spinach was stored at 3$^{\circ}C$, the concentration of residual captan decreased to 58.20, 61.37, 72.84 and 76.31% and the storage was carried out at -17$^{\circ}C$, residual captan amount decreased to 7.18, 22.67, 34.58 and 40.91% of the initial amout, respectively according to the storage period. In the case of the residual captan of seasoned spinach, the storage of 2, 24 and 48 hours at 15$^{\circ}C$, the amout of residual captan decreased to 0.772(39.69%), 0.661(77.50%) and 0.063ppm(97.86%) of the initial amount, respectively. When spinach was stored at 3$^{\circ}C$, the amount of residual captan decreased to 2.344 (20.22%), 1.021(65.25%) and 0.329ppm(88.80%) and the storage was carried out at -17$^{\circ}C$, residual captan amount decreased to 2.428(17.36%), 1.520(48.26%) and 0.726ppm(75.29%) of the initial amount, respectively according to the storage period. In the case of the residual captan of spinach cooked with edible oil for 2, 4 and 6 minutes and then cooking oil was discarded, each decreasing rate of the captan sticked to thespinach was 96.29, 97.86 and 99.18%, respectively. The rate of removed the captan sticked to the spinach with oil was 73.32, 86.32 and 87.13%, respectively. From these results, the storage in room temperature and the addition of seasoning to the spinach could lead to decrease in the concentration of the residual captan, furthemore the cooking could inhance decreasing of residual captan.

• Journal of Electrochemical Science and Technology
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• 제10권1호
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• pp.14-21
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• 2019

Supported liquid membrane process usually is used for recovering or enrichment of valuable metals in the industrial wastewater. But, even if the metals in the wastewater was separated with high chemical selectivity, it cannot be enough concentrated since separation performance of supported liquid membrane (SLM) process is limited by concentration gradient between feed solution and stripping solution. If metal concentration in the stripping solution to be enough low, transport of metal through membrane can be accomplishment constantly. Therefore, Electrodialysis (ED) has been placed after SLM process and the stripping solution of SLM was used as the feed solution for the ED process. Transport of ions in the solutions is successfully performed by ED process. Thus, the metal concentration in the stripping solution does not rise as to stop ion transport. Besides, valuable metals easily are concentrated by ED process for re-use. In this study, effects of operation parameters like initial Cd(II) concentration, HCl concentration in the feed solution of SLM and applied voltage are investigated on separation efficiency, flux and permeability of the both processes. As the feed solution concentration increased, all performance values has increased. When initial concentration of 100 mg/L is used, separation performances (SP) are 55% and 70%, for SLM and consecutive process, respectively. The best HCl concentration in the feed solution of SLM has determined as 2 M, in this conditions SP are 64% and 72%, for SLM and consecutive process, respectively. With increased of applied voltage on ED process, SP of the consecutive process has been raised from 72% to 83%. According to the obtained experimental data, consecutive process has better separation performance than SLM. When the separation performances of both processes were compared for the same operating conditions, it was determined higher the separation efficiency, permeability and flux values of the consecutive process, 8%, 9% and %10.6, respectively. Consequently, the use of the consecutive process increases the performance efficiency of both processes. The consecutive process studied has quite a good chemical separation efficiency, and enrichment capability. Moreover, this process requires few water and energy.