• Asian-Australasian Journal of Animal Sciences
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• v.13 no.7
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• pp.1010-1016
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• 2000

Effect on the bio-mass and nutrient yield of Lemna perpusilla Torry was studied at two nutrient loading frequencies. Six polythene sinks ($6{\times}2{\times}0.5m^{3}$ area) randomly allocated to two treatments having three sinks in each treatment. Each sink containing $6{\times}2{\times}0.35m^{3}$ water body, was changed either daily with 12.6 kg anaerobically fermented cattle manure (effluent) or with 76 kg efluent at six-day interval. Media Kjeldhal-N (40 vs. 36 mg/L; p>0.05) and $NH_3$-N (9 vs 7 mg/L; p<0.05) concentration were higher in daily charged sinks than those charged at six-day interval. However, temperature ($28.48{^{\circ}C}\;vs.\;28.60{^{\circ}C}$) and pH (6.82 vs. 6.84) were sinilar in both groups of sinks. Biomass (93 vs. $80g/m^{2}/d$) and crude protein (1.24 vs. $1.11g/m^{2}/d$) yield were non-significantly (p>0.05) higher in the daily charged than 6-d interval charged ponds. However, dry matter (4.52 vs. 4.15%), organic matter (83 vs. 84%), crude protein (31.4 va. 29.6%) and organic carbon (47 vs. 47%) content were similar in both daily and 6-d interval charged ponds. There were no apparent relationships between the crude protein content of Lemna and the media Kjeldhal-N or $NH_3$-N concentration apparently due to saturated level of nutrient (N in particular). It was concluded that with the level of effluent used for two treatments, nutrient-loading frequency had no significant effect on the biomass and protein yield of Lemna. Technique described here can be used for year-round duckweed production from fermented cattle manure for feeding poultry/fish in smallholder production system.

• KSBB Journal
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• v.15 no.4
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• pp.331-336
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• 2000

The antimutagenic activity of the extract of Artemisia capillaris THUNB on the mutagenicity induced by benzo(a)pyrene [B(a)P] in the presense of S9 mixture was studied using bacterial mutagenic assay system. Samples harvested in summer and autumn were extracted using ethanol and hot water. Among these extracts the water extract of summer sample had the strongest inhibitory effect against the mutagenenicity of B(a)P, The water extract of Artemisia capillaris THUNB was separated again into ethanol soluble and insoluble parts. The ethanol insoluble part(El) of water extract exhibited higher inhibition effects than the ethanol soluble part against the mutagenic activity of B(a)P. El showed dose-dependent activity on the mutagenicity of B(a)P in SOS Chromotest and Ames test. The 50% inbibition concentraction $(IC_{50}$ of El were $200{\mu}g/assay$ $600{\mu}g/plate$ and $800{\mu}b/plate$ in E. coil PQ37 S. typhimurium TA100 and TA98 respectively. El were showed desmutagenic effect but had no effect on the DNA repair system for B(a)P-induced mutagenesis. HPLC analysis showed that the formation of aflatoxin M1 by cytochrome P-450 1A1 known as playing an impotant role on B(a) P-induced mutagenicity was highly inhibited by El. Therefore we encluded that B(a)P-induced mutagencity can be reduced possible due to the interference of el with cytochrome P-450 1A1-dependent bioactivation.

• Journal of Korean Society on Water Environment
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• v.26 no.3
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• pp.518-524
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• 2010

Continuous removal of organic matters (CROM) using freshwater bivalve Anodonta woodiana was operated to evaluate the effect of water current on the water quality improvement (clearance) of eutrophic lake. The CROM system comprised three treatment steps such as flow control, treatment and analysis, and operated at the two different currents ($24L\;h^{-1}$ and $48L\;h^{-1}$) with mussels at density of $312.5indiv.\;m^{-2}$ for 12 consecutive days. Water quality including suspended solids (SS) and chlorophyll-a (Chl-a) was daily measured at the same time. Results indicate that although both the system strongly decreased the concentration of SS and chl-a, a slow CROM system was more effective to diminish the SS contents than a fast CROM system; 82% and 66%, respectively (ANOVA, P<0.0001). Clearance rates, based on chl-a, were also significantly higher in a slow system than a fast system (ANOVA, P<0.0001), although the mussel mortality was conversely. In both systems, there showed a remarkable excretion of dissolved inorganic nutrients (i.e. $NH_3-N$ and $PO_4-P$), while a slow CROM system was higher than a fast system, significantly (ANOVA, P<0.0001). Therefore, it may suggest that a slow current CROM system is more suitable to maximize the efficacy of water quality improvement, but further study is needed to diminish the mortality of mussel and to reuse the nutrient released during the operation.

• Korean Journal of Poultry Science
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• v.20 no.2
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• pp.55-64
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• 1993

The experiment was conducted to compare the effects of supplements of copper, vitamin I and selenium on growth and immune responses of broiler chicks fed cornsoy diets. The basal diet contained 21% crude protein, 2,800 kcal ME, 10 mg Vitamin E, 10 mg copper and 0.1 mg selenium per kg diet. Additions of the basal diet were copper (150mg and 250 mg/kg) or combination of vitamin I(200 mg/kg) and selenium(2 mg/kg). Serum immunoglobulin G(IgG) concentrations and body weight gain were determined weekly from hatching to 7 weeks of age. Additions of copper(150mg, 250mg) to the basal diet were showed, at the four weeks of age, 4.8% and 4.5% higher in body weight gain than that of control group, respectively. The active immune system of copper and (Vit. E＋Se) treated groups developed one week earlier than control group(basal diet). Negative correlation between IgG concentration and body weight gain was showed at the period from hatching to three weeks of age and, thereafter, positive correlation were identified (p＜0.01). Mortality rates were observed lower in all treated groups than that of control. In conclusion, the lower the levels of serum IgG, at the first two weeks of age, the lower in disease Infection and the higher in body weight gain.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.4
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• pp.289-303
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• 2009

The chemical and meteorological effects on the concentration variations of ozone ($O_3$) were evaluated based on the intensive air quality measurement (5 pollutants and aromatic volatile organic compounds (AVOCs)) in and out-side an urban valley during spring and summer of 2006. The 5 pollutants measured in the study area include $O_3$, $NO_2$, NO, $PM_{10}$, and CO; the AVOCs include benzene (BEN), toluene (TOL), ethylbenzene (EB), m,p-xylene (MPX), and o-xylene (OX). For the purpose of this study, study areas were classified into two categories: valley area (VA) with a semi-closed topography covering a number of industrial complex, public building, and mountains and non-valley area (NVA) surrounding the suburban and residential areas. In general, the mean concentration levels of most pollutants (except for $PM_{10}$) in the VA were higher than those in the NVA. It was found that the average $O_3$ increase in the VA during spring might result from the combined effects such as the photochemical production from diverse anthropogenic sources and the $O_3$ accumulation due to geographical features (e.g., the semi-closed topography) and wind conditions (e.g., a low wind speed). In addition, the nocturnal $O_3$ increase in the VA during spring was primarily caused by local wind conditions (e.g., mountain and valley winds) with the low wind speed (approximately $1{\sim}2\;m\;s^{-1}$). On the other hand, the $O_3$ difference between the two areas during summer might be because of the photo-chemical production with the $O_3$ precursors (especially the AVOCs) rather than the contribution of wind conditions.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10b
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• pp.921-927
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• 1988

The process and results of computer simulation using bond graphs for a hydraulic system driving large rotational inertia are presented in this paper. As the large rotational inertia and its application characteristics, control criteria of this system is not position-control nor velocity-control but appropriate acceleration, deceleration and inching ability. All the components' nonlinear characteristics are modelled using bond graphs. The equationing and solution process is carried out by a package. Finally it is concluded that modelling of this kind of system by bond graphs and using a software as its solver shows good approximated results to actual experimental data, and that the proposed modelling may be useful to actual design process for this kind of hydraulic system.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.12
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• pp.1118-1122
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• 2006

In this study, in order to develop the low temperature sintering multilayer piezoelectric actuator, PMN-PNN-PZT system ceramics were manufactured and their microstructure, ferroelectric and piezoelectric properties were investigated. By increasing sintering temperature, remanent polarization$(P_r)$ was increased due to the increase of sinterability and grain size. However, coercive $field(E_c)$ showed an opposite tendency to remanent polarization owing to the feasibility of domain wall motion. At the sintering temperature of $900^{\circ}C$, dielectric $constant({\varepsilon}_r)$, electromechanical coupling $factor(k_p)$, piezoelectric $constant(d_{33})$ and mechanical quality $factor(Q_m)$ showed the optimal value of 1095, 0.60, 363 and 1055, respectively, for multilayer piezoelectric actuator application.

• Journal of Soil and Groundwater Environment
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• v.11 no.6
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• pp.76-82
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• 2006

Fenton's reaction are difficult to apply in the field due to the low pH requirements for the reaction and the loss of reactivity caused by the precipitation of iron (II) at neutral pH. Moreover, Fenton-like reactions using iron mineral instead of injection of iron ion as a catalyst are operated to get high removal result at low pH. Because hydroxyl radical can generate at the surface of iron mineral, there are competition with a lot of hydroxide at around neutral pH. On the other side, to operate Fenton's reaction series at neutral pH, modified Fenton reaction is suggested. The complexes, composed by iron ions (ferrous ion or ferric ion)-chelating agent, could be acted as a catalyst and presented in the solution at neutral pH. However, modified Fenton reaction requires a lot of hydrogen peroxide. Accordingly, the purpose of this experiment was to effectively combine Fenton-like reaction and modified Fenton reaction for extending application of Fenton's reaction. i.e., injecting chelating agents in Fenton-like reaction at around neutral pH is increasing the concentration of dissolved iron ion and highly promoting the oxidation effect. 2,4,6-trinitrotoluene (TNT) was used as a probe compound for comparing reaction efficiencies in this study. If the concentration of dissolved iron ion in combined Fenton process were existed more than 0.1 mM, the total TNT removal were increased. Magnetite-NTA system showed the best TNT removal (76%) and Magnetite-EDTA system indicated about 56% of TNT removal. The results of these experiments proved more promoted 40-60% of TNT removal than Fenton-like reaction's.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.36 no.4
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• pp.303-314
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• 2010

In this study, the antibacterial, antioxidative effect and component analysis of Pinus koraiensis leaf extracts were investigated. MIC values of the ethyl acetate fraction from P. koraiensis leaf extracts on P. acnes, S. aureus, P. ovale, and E. coli were 0.06 %, 0.25 %, 0.13 % and 0.50 %, respectively. The results showed that the antibacterial activity of the ethyl acetate fraction on P. acnes, P. ovale. and S. aureus was more prominent. The aglycone fraction of P. koraiensis leaf extracts ($22.93\;{\mu}g/mL$) showed more higher free radical (1,1-diphenyl-2-picrylhydrazyl, DPPH) scavenging activity ($FSC_{50}$). Reactive oxygen species (ROS) scavenging activity ($OSC_{50}$) of P. koraiensis leaf extracts on ROS generated in $Fe^{3+}$-EDTA/$H_2O_2$ system was investigated using the luminol-dependent chemiluminescence assay. The 50 % ethanol extract ($0.70\;{\mu}g/mL$) showed the most prominent ROS scavenging activity. Also the ethyl acetate ($1.04\;{\mu}g/mL$) and the aglycone fraction ($1.43\;{\mu}g/mL$) showed very high antoxidant activity. The protective effects of extract/fractions of P. koraiensis leaf extracts on the rose-bengal sensitized photohemolysis of human erythrocytes were investigated. The P. koraiensis leaf extracts showed cellular membrane protective effects in a concentration dependent manner ($5{\sim}50\;{\mu}g/mL$). TLC and HPLC chromatogram of the ethyl acetate fraction obtained from hydrolysis of P. koraiensis leaf extracts revealed 2 main bands (PK-4, PK-6) and peaks (peak 1, peak 2), which were identified as kaempferol-3-O-glucoside (PK-6, peak 1) and kaempferol-3-O-arabinoside (PK-4, peak 2) by LC/ESI-MS/MS, respectively. These results indicate that extract/fractions of P. koraiensis can function as antioxidants in biological systems, particularly skin exposed to UV radiation by scavenging ROS, and protect cellular membrane against ROS. Extract/fractions of P. koraiensis can be applicable to new cosmeceuticals for antioxidant, antiaging, and antibacterial activity.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2149-2151
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• 1999

This paper describes the impulse response characteristics of the grounding systems in power utility system. Several regulations regarding to electric power equipments, services and managements require that the groundings of class 1 ($E_1$) and class 2 ($E_2$) must be connected at the common point in grounding systems. In addition, the grounding for arrester ($E_{LA}$), which belongs to the grounding of class 1, should be connected at the same point. However, there is no method and position of common-connection at anywhere. In this work, when the impulse current was injected through the grounding conductor for arrester, the investigations measuring and analyzing potential rises induced at the common connection point and other grounding conductors were conducted. The experiments were carried out in the conditions of the grounding conductor of 25m long and the near or remote common connection from ground electrode. The lightning impulse current was applied so as to simulate the on-set of arrester due to lightning and/or switching surges.