• 청정기술
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• 제27권1호
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• pp.47-54
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• 2021

입상 활성탄(GAC)에 대한 Acid Fuchsin (AF)의 흡착을 염료의 초기농도, 접촉 시간, 온도 및 pH 를 흡착변수로 실험하여 등온흡착과 동력학적, 열역학적 파라미터에 대해 조사하였다. pH 변화실험에서 활성탄에 대한 AF의 흡착은 pH 3과 11에서 모두 흡착이 증가하는 욕조형을 나타냈다. AF의 흡착평형자료는 Freundlich 등온식에 잘 맞았으며, 계산된 분리계수(1/n) 값으로부터 활성탄이 AF를 효과적으로 제거할 수 있다는 것을 알았다. 흡착공정은 유사 이차 반응속도식이 오차율 7.88% 이내로 잘 맞았다. Weber와 Morris 모델의 Polt에 따르면 두 단계의 직선으로 구분되었다. stage 2 (입자내 확산)의 기울기가 stage 1 (경계층 확산)의 기울기 보다 작아서 입자내 확산속도가 느렸다. 따라서 입자 내 확산이 속도지배단계인 것을 확인하였다. AF의 활성화 에너지(13.00 kJ mol-1)는 물리흡착공정(5 ~ 40 kJ mol-1)에 해당하였다. 활성탄에 의한 AF 흡착의 자유에너지 변화는 298 ~ 318 K에서 모두 음의 수치를 나타냈으며, 온도가 증가할수록 자발성이 더 높아졌다. AF 흡착은 흡열반응(ΔH = 22.65 kJ mol-1)으로 나타났다.

• 대한수의학회지
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• 제32권2호
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• pp.157-164
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• 1992

Changes in the both inward current and conductance of membrane by the fertilization were observed using the one microelectrode voltage clamp(or switch clamp) technique. Unfertilized eggs and both 1- and 2-cell stage eggs after fertilization were donated from the superovulated mouse (ICR, more than 6 weeks old) treated with PMSG(pregnant mare serum gonadotropin, Sigma) and HCG(human chorionic gonadotropin, Sigma) and naturally mated ones, respectively in this experiment. Membrane potential was held at -90mV and the voltage step was applied from -80mV to 50mV with interval of 10mV or 20mV for 300ms. since both of amplitudes and time courses in the membrane currents were various according to the states of cells and clamping condition, results were presented by their $averages{\pm}SEM$(standard mean error)and ratios or percentages. Inward currents began to appear in response to the step depolarization from -60mV and reached its maximum at -50mV. However, since the potential was not clamped evenly during the voltage step, current-voltage(I-V) relationship might be positively shifted 10 or 20mV. From the steady-state currents plotted in the I-V curve, outward rectification was markedly observed. Peak inward currents$(i_{in})$ at -50mV were $-0.62{\pm}0.23nA$(n=4),$-0.52{\pm}0.25nA$(n=5) and $-0.37{\pm}0.25nA$(n=6), in the 1-cell stage, 2-cell stage fertilized eggs and in the unfertilized eggs, respectively. Pure inward current (difference between steady-state and peak, $i_{in. pure}$) were $-1.01{\pm}0.23nA$, $-0.69{\pm}0.43nA$ and $-0.68{\pm}0.29nA$, respectively in the 1-cell stage fertilized eggs, unfertilized eggs and 2-cell stage fertilized eggs. These results suggested that the outward current in fertilized eggs of 2-cell stage was more increased than those in the unfertilized eggs. Pure inward currents in the all stages of eggs showed a similar fashion in the I-V relationship from -50mV to 50mV and reversal potential at 50mV. Time constant of inactivation$({\tau})$ in the inward current was decreased as the membrane potential was depolarized in the unfertilized and 2-cell stage eggs but in the 1-cell stage eggs t was not likely to be affected significantly. Slope conductances were 14.2nS, 8.9n5 and 7.7nS in the 1-cell, 2-cell stage fertilized eggs and the unfertilized eggs, respectively. Membranes between two cells within a zona pellucida seem to be electrical-connected in the 2-cell stage eggs from the observation made in the analysis for the electronic spread and decay to the current stimuli. Both of inward current and membrane conductance were increased after fertilization in the mouse eggs. Inward current seems to be carried by the same ion or through the same channels up to the 2-cell stage and ion that carried inward current was thought to play important function after fertilization in the mouse eggs.

• 한국컴퓨터정보학회논문지
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• 제29권6호
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• pp.167-173
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• 2024

본 연구에서는 컴퓨터로 제어되는 초음파를 이용하여 피하 조직의 탄성도를 도출할 수 있는 방법을 개발하였다. 림프 부종은 유방암 수술에서 흔한 합병증으로 유방암 생존자에 있어 삶의 질을 저하시키는 주요 원인으로 알려져 있다. 그러나 아직 부종 조직의 성상을 정량적으로 분석할 수 있는 방법은 정립되어 있지 않다. 유방암 수술 이후 한 쪽 상지에 부종으로 인한 불편감을 호소하는 환자를 대상으로 총 30례의 부종 조직과 그에 상응하는 정상 조직에서의 초음파 분석을 수행하였고, 건측과 환측 간 탄성도의 차이를 도출하였다. 그에 따라 차이가 음수인 더 딱딱한 그룹과(n=13) 양수인 더 부드러운 그룹으로(n=17) 분류하였다. 컴퓨터 제어 초음파 검사와 실시간 압력 센서를 이용한 피하 조직 탄력성 평가는 유방암 수술 후 발생한 림프 부종 환자에서 조직의 성상을 분석할 수 있는 유용한 도구가 될 것이다.

• 대한수의학회지
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• 제39권6호
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• pp.1081-1090
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• 1999

To establish the protocol of a standardized exercise test for evaluating exercise intolerance and degree of fitness in Thoroughbred racehorses, we examined serum lactate concentrations related to exercise intensities using the high speed treadmill. Twelve clinically healthy Thoroughbred racehorses with or without previous training or racing history were assigned to two gorups, fit and unfit group, respectively. The protocol used for the standardized exercise test was consisted of two stages : stage of warm-up and that of acceleration. During the warm-up, the horses exercised 5 min at 1.8m/s and 3 min 3.4m/s without inclination. At the acceleration stage, exercise test was performed at 10% slope and the speed was increased from the initial 5m/s to the maximal speed which each tested horse could keep up with. The speed was increased with incremental steps of 1 m/s every minute. During the last 15 sec of each step, blood samples were collected for serum lactate determination. $V_{max}$(maximal treadmill speed which tested horses could keep up with) of the fit group ($10.93{\pm}0.33m/s$, mean${\pm}$SE, n = 6) was higher than that of the unfit group ($9.52{\pm}0.23m/s$, mean${\pm}$SE, n = 6). Serum lactate concentrations increased exponentially according to exercise intensities. $V_{La4}$(speed producing a serum lactate concentration of 4mmol/l) of the fit group, $6.45{\pm}0.26m/s$, was higher than that of the unfit group, $5.45{\pm}0.23m/s$. $La_{peak}$(peak plasma lactate concentration during the exercise test) was lower in the fit group ($20.34{\pm}1.62mmol/l$ at 1 min after maximal intensity exercise) than in the unfit group ($24.78{\pm}1.09mmol/l$ at 2 min after maximal exercise step). $t_{50%}$(time required for the recovery of lactate concentration to be one-half of $La_{peak}$ after maximal exercise) of the unfit group and the fit group were 40.0 and 18.0 min, respectively. Therefore, the protocol of the incremental standardized exercise test utilized in this study seems to be reliable for the assessment of fitness and exercise intolerance for the Thoroughbred racehorses.

• Advances in concrete construction
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• 제2권3호
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• pp.177-192
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• 2014

One of the main applications of FRP composites is confining concrete columns. Hence identifying the cyclic and monotonic stress-strain behavior of confined concrete columns and the parameters influencing this behavior is inevitable. Two significant parameters affecting the stress-strain behavior are aspect ratio and corner radius. The present study aims to scrutinize the effects of corner radius and aspect ratio on different aspects of stress-strain behavior of FRP confined concrete specimens (rectangular, square and circular). Hence 44 FRP confined concrete specimens were tested and the results of the tests were investigated. The findings indicated that for specimens with different aspect ratios, the relationship between the ultimate stress and the corner radius is linear and the variations of the ultimate stress versus the corner radius decreases as a result of an increase in aspect ratio. It was also observed that increase of the corner radius results in increase of the compressive strength and ultimate axial strain and increase of the aspect ratio causes an increase of the ultimate axial strain but a decrease of the compressive strength. Investigation of the ultimate condition showed that the FRP hoop rupture strain is smaller in comparison with the one obtained from the tensile coupon test and also the ultimate axial strain and confined concrete strength are smaller when a prism is under monotonic loading. Other important results of this study were, an increase in the axial strain during the early stage of unloading paths and increase of the confining effect of FRP jacket with the increase and decrease of the corner radius and aspect ratio respectively, a decrease in the slope of reloading branches with cycle repetitions and the independence of this trend from the variations of the aspect ratio and corner radius and also quadric relationship between the number of each cycle and the plastic strain of the same cycle as well as the independence of this relationship from the aspect ratio and corner radius.

• 한국수자원학회논문집
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• 제30권6호
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• pp.597-610
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• 1997

본 연구에서는 하도 내에서의 부정류 유사이송으로 인한 하상변동의 일차원적 수치모델들을 개발하였다. 유사량과 하상변동에 대한 수치해를 얻기 위해 흐름의 방정식은 Preissmann 음해법과 Lax-Wendroff 2단 양해법을 그리고 유사의 연속방정식은 시간 전방차분, 공간 중앙차분 양해법을 사용하여 수치 적분하였고, Lax-Wendroff 기법 내에서 상류와 하류의 추가 경계조건을 구하기 위해 특성곡선법을 적용하였다. 모델의 정확도는 부피보존실험을 통하여 성공적으로 입증되었으며, 모델의 주요 변수들에 대한 민감도 분석결과로부터 보다 큰 최대 홍수위, 하상경사 및 홍수지속기간에 의해 큰 하상세굴이 발생하였고, 하상재료의 평균입경 가운데, $D_{50}=0.4mm$에서 가장 큰 하상변동을 가져왔다. 본 연구에서 개발된 모델들이 각 변수들의 변화에 적절한 반응을 함으로써 모델들이 합리적인 결과를 가져다주는 것으로 결론되어지며, 실제하천에 적용될 수 있는 것으로 판단된다.

• 한국농공학회지
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• 제32권4호
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• pp.27-43
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• 1990

This study aimed at developing a generalized model on the estimation of the long - term run - off volume for practical purpose. During the research period of last 3 years( 1986-1988), 3 types of estimation model on the long - term run - off volume(Effective rainfall model, unit hydrograph model and barne's model for dry season) had been developed by the author. In this study, through regressional analysis between determinant factors (bi of effective rainfall model, ai of unit hydrograph model and Wi of barne's model) and catchment characteris- tics(catchment area, distance round the catchment area, massing degree coefficient, river - exte- nsion, river - slope, river - density, infiltration of Watershed) of 11 test case areas by multiple regressional method, a new methodology on the derivation of determinant factors from catchment characteristics in the watershed areas having no hydrological station was developed. Therefore, in the resulting step, estimation equations on run - off volume for practical purpose of which input facor is only rainfall were developed. In the next stage, the derived equations were applied on the Kang - and Namgye - river catchment areas for checking of their goodness. The test results were as follows ; 1. In Kang - river area, average relative estimation errors of 72 hydrographs and of continuous daily run - off volume for 245 days( 1/5/1982 - 31/12) were calculated as 6.09%, 9.58% respectively. 2. In Namgye - river area, average relative estimation errors of 65 hydrographs and of conti- nuous daily run - off volume for 2fl days(5/4/1980-31/12) were 5.68%, 10.5% respectively. In both cases, relative estimation error was averaged as 7.96%, and so, the methodology in this study might be hetter organized than Kaziyama's formula when comparing with the relative error of the latter, 24~54%. However, two case studies cannot be the base materials enough for the full generalization of the model. So, in the future studies, many test case studies of this model should he carries out in the various catchment areas for making its generalization.

• 한국농공학회논문집
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• 제54권4호
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• pp.19-27
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• 2012

The objective of this study was to test the pollutant reduction effect by the silt fence and vegetated ridge through field monitoring. The experiment plots were established with two replication and three treatments. Each plot was designed with 5 m width, 22 m length, and 3 % slope. Flumes with the floating type stage gages were installed at the outlet of each plot to monitor the runoff. For a rainfall monitoring, tipping bucket rain gage was installed within the experiment site. Cultivated crops were spring daikon and autumn chinese cabbage. Analysis of variance (ANOVA) indicated that the water quality concentration from three experiment plots were not significantly different in 5 % of significant level. The monitoring results showed that the average pollution loads reduced by silt fence compared to control were SS 75.33 %, TN 40.87 %, TP 56.58 %, BOD 52.12 %, COD 36.07 %, TOC 34.99 %; by vegetated ridge compard to control were SS 65.27 %, TN 81.80 %, TP 54.26 %, BOD 67.09 %, COD 46.55 %, TOC 43.30 %. Analysis of Spearman's rank correlation coefficient showed that BOD-SS and SS-Turbidity were highly related at the silt fence and vegetated ridge plots. In all plots, SS-Turbidity and TP-TN relations were relatively high. The monitoring results showed that the silt fence and vegetated ridge were effect method to reduce the pollutant loads from the field runoff. Long-term monitoring is required to obtain more quantitative reduction effect for diverse crops and to increase the reliability of results.

• 한국환경복원기술학회지
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• 제2권4호
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• pp.64-73
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• 1999

This study was conducted to find out the effects of hydroseeding material and seed mixture on the revegetation of rock cut-slopes by PEC4 (Polymer-Ecology-Control) Hydroseeding Measures. PEC4 hydroseeding material was applied to four cut-slopes using hydroseeding measures from April to August, 1999, and the field survey was carried out by monthly. PEC4 material consisted of bark compost and organic soil amendments. This material has high content of organic matter and high level of water holding capacity. PEC4 hydroseeding material shows low level of soil hardness, so it gives to good condition for seed germinating and plant growing in early stage. PEC4 material attached at rock cut-slopes by two types of adhesive agent was not eroded by rainfall. The plant coverage and number of plant species were affected by mixing ratio of seeds and seeding timing. From the viewpoint of plant establishment, the optimal hydroseeding timing of mixed seeds for plant growth seems to be in May. Most of the plant seeds were germinated well and they covered rock cut-slopes so quickly and effectively. Plant importance value of Silene armeria and Platycodon grandiflorum. were higher than any other seeded-native species in the competition between native species and exotic species, so they have enough possibility to be used for slope revegetation works. Thus it leads to conclusion that the revegetation method used in this experiment was a very effective method for plant establishment on rock cut-slopes.

• Asian Journal of Atmospheric Environment
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• 제2권1호
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• pp.14-25
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• 2008

Benzene, toluene, ethyl benzene and m-, p-, and o-xylene, the most influential aromatic volatile organic compounds (VOCs), were measured in Bangkok, Thailand, one of the most rapidly developing urban areas in Southern East Asia. The purpose of this study is to characterize the ambient air quality with respect to above mentioned aromatic compounds. The data were monitored in ten sites which cover roadside area, residential area and background area. Canister technique was used to obtain air sample at 24 hour interval per a month during April-August in 2007. GC/MS with three stage preconcentrator was used to analyze these samples. The average concentrations of benzene, toluene, ethyl benzene m-, p-xylene and o-xylene are 5.8, 36.1, 4.1, 11.0 and $3.7{\mu}g/m^3$, respectively. They were observed to be distributed in a log-normal form. Moreover, o-xylene and m, p-xylene exhibited a very good correlation (r=0.976). The slope of the regression equation between them was 3.07 which consisted with a previous reported value. The average ratio of toluene to benzene was 6.4 in April, May June and August. This value was comparable to the ones measured in other Asian cities. Two types of statistical analyses, cluster and factor analyses, were applied to the data in this study. Well characterization was made to understand the air quality of Bangkok area.