• Journal of the Korean Society of Safety
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• v.8 no.4
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• pp.27-40
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• 1993

High temperature tensile tests, steady state creep tests, Internal stress tests and creep rupture tests using A17075 alloy( $T_{6}$ ) were performed over the temperature range of 9$0^{\circ}C$~50$0^{\circ}C$ (0.4 $T_{m}$ ~0.85 $T_{m}$ ) and stress range of 0.64~17.2(kgf/$\textrm{mm}^2$). The main results obtained in this paper were as follows. (1) The activation energies for yielding at the temperature of 0.4 $T_{m}$ ~0.75 $T_{m}$ were calculated to be 25.7~36.5kcal/mol, which were nearly equal to the activation energies for creep. (2) At around the temperature of 9$0^{\circ}C$~12$0^{\circ}C$ and under the stress level of 10~17.2(kgf/$\textrm{mm}^2$), and at around the temperature of 200~41$0^{\circ}C$ and under the stress level of 1.53~9.55(kgf/$\textrm{mm}^2$) and again at around the temperature of 470~50$0^{\circ}C$ and under the stress level of 0.62~l.02(kgf/$\textrm{mm}^2$), the applied stress dependence of steady state creep rate $n_{measu}$ measured were, respectively, 3.15, 6.62 and 1.1, which were in good agreement the calculated stress dependence $n_{ealeu}$ obtained by the difference of the applied stress dependence of the Internal stress and the ratio of the internal stress to the applied stress. (3) At the temperature range of 0.4~0.43 $T_{m}$ , and at the temperature range of 0.52~0.75 $T_{m}$ and again at the temperature range of 0.82~0.85 $T_{m}$ , the activation energies $Q_{measu}$ obtained by steady state creep rate, respective, 26. 16, 34.9, 36.2 and 36.1kcal/mol, which were in good agreement with those obtained with the activation energies under constant effective stress and the temperature dependence of Internal stress. (4) At the temperature range of the 0.52~0.73 $T_{m}$ and under the stress level of 1.53~9.55(kgf/$\textrm{mm}^2$), the stress dependence of rupture life(n’) measured was 6.3~6.6, which was in good agreement with the stress dependence of steady state creep rate(n). And at the same condition the activation energy for rupture( $Q_{f}$ ) measured was 32.0~36.9kca1/mol, which was also in good agreement with the activation energy obtained by steady state creep rate ( $Q_{c}$ ). (5) The rupture life( $t_{f}$ ) might be represented by athermal process attributed to the difference of the applied stress dependence of the internal stress and the ratio of the internal stress to the applied stress, and the thermal activated process attributied to the temperature dependence of the internal stress as $t_{f}$ = A'$\sigma$$_{a}$ ｛n(1-d $\sigma$$_{i}$ /d $\sigma$$_{a}$ )/(1-$\sigma$$_{i}$ / $\sigma$$_{a}$ )｝.exp[｛ $Q_{c}$ $^{*}$-( $n_{o}$ R $T^2$/ $E_{(T)}$) (d $E_{(T)}$/dT) - ( $n_{0}$ R $T^2$/ $\sigma$$_{a}$ - $\sigma$$_{i}$ ) (d $\sigma$$_{i}$ /dT)｝/RT]. (6) The relationship betwween Larson-Miller rupture parameter and logarithmic stress was linearly decreased, so creep rupture life of Al 7075 alloy seemed to be predicted exactly with Larson-Miller parameter.meter.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.38 no.2
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• pp.95-107
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• 2020

The purpose of this study is to provide the basic data by analyzing and analysing the Growth Conditions of old Trees in Yangdong village. This study investigated about the conducted on tree information, soil information, and tree health. The result are as follows. The trees information in Yangdong Village consists of Juniperus chinensis, Salix chaenomeloides, Salix pseudolasiogyne, Celtis sinensis, Zelkova serrata, Gleditsia japonica, and Gleditsia sinensis trees, The range of height was 4.0~17.0m, and the diameter was 0.51~1.34m, Juniperus chinensis trees of No.17 was most large. In the results of soil analysis, there showed that acidity was pH4.1~6.3, hardness of 5~48mm, organic matter content of 21.2~29.1g/kg, electrical conductivity(EC) of 0.34~1.76dS/m, available P₂O₅ of 79.8~451.6mg/kg, exchangeable K of 0.22~1.71cmol+/kg, exchangeable Ca of 4.98~7.44cmol+/kg, exchangeable Mg of 0.67~2.19cmol+/kg, exchangeable Na of 0.19~1.04cmol+/kg and cation exchange capacity(C.E.C) of 7.23~13.02cmol+/kg. As a result, the highest number of tree health levels is 8 of 11trees of Celtis sinensis, 2 of 7trees of Zelkova serrata, and 3 of Gleditsia sinensis, and 13 of 30 trees of health levels, The Older trees with high infection, spoil and hollowed part were the remaining trees except for the healthy part. Relatively, more than half of the number of targets is infected, decay, and the hollowed site, and it is necessary to perform surgery on the damaged area. In addition, preservation and protection measures should be implemented by supplying root nutrients for trees, controlling nutrients in the body to prevent secondary and tertiary damages that cause the infection site to metastasize to the health site, In order to continually monitor the trees, measures to improve the location environment and management of the trees should be sought.

• Economic and Environmental Geology
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• v.31 no.3
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• pp.185-199
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• 1998

Hydrogeochemical and environmental isotope studies were undertaken for various kinds of water samples collected in 1995-1996 from the Bugok geothermal area. Physicochemical data indicate the occurrence of three distinct groups of natural water: Group I ($Na-S0_4$ type water with high temperatures up to $77^{\circ}C$, occurring from the central part of the geothermal area), Group II (warm $Na-HCO_{3}-SO_{4}$ type water, occurring from peripheral sites), Group III ($Ca-HCO_3$ type water, occurring as surface waters and/or shallow cold groundwaters). The Group I waters are further divided into two SUbtypes: Subgroup Ia and Subgroup lb. The general order of increasing degrees of hydrogeochemical evolution (due to the degrees of water-rock interaction) is: Group III$\rightarrow$Group II$\rightarrow$Group I. The Group II and III waters show smaller degrees of interaction with rocks (largely calcite and Na-plagioclase), whereas the Group I waters record the stronger interaction with plagioclase, K-feldspar, mica, chlorite and pyrite. The concentration and sulfur isotope composition of dissolved sulfate appear as a key parameter to understand the origin and evolution of geothermal waters. The sulfate was derived not only from oxidation of sedimentary pyrites in surrounding rocks (especially for the Subgroup Ib waters) but also from magmatic hydrothermal pyrites occurring in restricted fracture channels which extend down to a deep geothermal reservoir (typically for the Subgroup Ia waters). It is shown that the applicability of alkaliion geothermometer calculations for these waters is hampered by several processes (especially the mixing with Mg-rich near-surface waters) that modify the chemical composition. However, the multi-component mineral/water equilibria calculation and available fluid inclusion data indicate that geothermal waters of the Bugok area reach temperatures around $125^{\circ}C$ at deep geothermal reservoir (possibly a cooling pluton). Environmental isotope data (oxygen-18, deuterium and tritium) indicate the origin of all groups of waters from diverse meteoric waters. The Subgroup Ia waters are typically lower in O-H isotope values and tritium content, indicating their derivation from distinct meteoric waters. Combined with tritium isotope data, the Subgroup Ia waters likely represent the older (at least 45 years old) meteoric waters circuated down to the deep geothermal reservoir and record the lesser degrees of mixing with near-surface waters. We propose a model for the genesis and evolution of sulfate-rich geothermal waters.

• Applied Biological Chemistry
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• v.51 no.1
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• pp.70-78
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• 2008

Prunus sargentii R. of Rosaceae familiy, has been reported to have radical scavenging activity and anti-inflammatory effect. On these facts, biological activity and safety test were conducted to evaluate biological activities of the extracts of P. sargentii R. as a potential pharmaceutical ingredient. The electron donating ability of its ethanol extracts at a 500 ppm level showed 92%, which was higher than that of hot water extract (59%), the superoxide dismutase (SOD)-like activity of the water extract of P. sargentii R. was about 50%, the ethanol extract of P. sargentii R. was about 40% at 1,000 ppm concentration. Xanthine oxidase inhibition by the water extract of P. sargentii R. was about 40% and that by the ethanol extract was 60% respectively at 500 ppm concentration. From the measurement on lipid oxidation, the $Cu^{2+}$ chelating effect of the ethanol extract was higher than that of hot water extract. The $Fe^{2+}$ chelating effect was also shown to be about 80% at a 500 ppm concentration in both hot water extract and ethanol extract. The tyrosinase inhibition effect related to skin-whitening was 26% by hot water extract and 20% by ethanol extract respectively at a 1,000 ppm. Hyaluronidase inhibition activity related to the anti-inflammation effect was 96% in ethanolic extract at a 500 ppm. Clear zones formed by P. sargentii R. against the human skin-resident micro-flora such as Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli and Propionibacterium acnes indicated that antimicrobial activity of the ethanol extract was higher than that of the hot water extract.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.4
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• pp.875-884
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• 2000

Sea fog/stratus is very difficult to detect because of the characteristics of air-sea interaction and locality ,and the scantiness of the observed data from the oceans such as ships or ocean buoys. The aim of our study develops new algorism for sea fog detection by using Geostational Meteorological Satellite-5(GMS-5) and suggests the technics of its continuous detection. In this study, atmospheric synoptic patterns on sea fog day of May, 1999 are classified; cold air advection type(OOUTC, May 10, 1999) and warm air advection type(OOUTC, May 12, 1999), respectively, and we collected two case days in order to analyze variations of water vapor at Osan observation station during May 9-10, 1999.So as to detect daytime sea fog/stratus(OOUTC, May 10, 1999), composite image, visible accumulated histogram method and surface albedo method are used. The characteristic value during day showed A(min) .20% and DA < 10% when visible accumulated histogram method was applied. And the sea fog region which is detected is similar in composite image analysis and surface albedo method. Inland observation which visibility and relative humidity is beneath 1Km and 80%, respectively, at OOUTC, May 10,1999; Poryoung for visble accumulated histogram method and Poryoung, Mokp'o and Kangnung for surface albedo method. In case of nighttime sea fog(18UTC, May 10, 1999), IR accumulated histogram method and Maximum brightness temperature method are used, respectively. Maxium brightness temperature method dectected sea fog better than IR accumulated histogram method with the charateristic value that is T_max < T_max_trs, and then T_max is beneath 700hPa temperature of GDAPS(Global Data Assimilation and Prediction System). Sea fog region which is detected by Maxium brighness temperature method was similar to the result of National Oceanic and Atmosheric Administratio/Advanced Very High Resolution Radiometer (NOAA/AVHRR) DCD(Dual Channel Difference), but usually visibility and relative humidity are not agreed well in inland.

• Restorative Dentistry and Endodontics
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• v.35 no.2
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• pp.80-87
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• 2010

The purpose of this study was to compare the different canal irrigation methods to prevent the formation of precipitate between sodium hypochlorite (NaOCl) and chlorhexidine (CHX). Extracted 50 human single-rooted teeth were used. The root canals were instrumented using NiTi rotary file (Profile .04/#40) with 2.5% NaOCl and 17% EDTA as irrigants. Teeth were randomly divided into four experimental groups and one control group as follows; Control group: 2.5% NaOCl only, Group 1: 2.5% NaOCl + 2% CHX, Group 2: 2.5% NaOCl + paper points + 2% CHX, Group 3: 2.5% NaOCl + preparation with one large sized-file + 2% CHX, Group 4: 2.5% NaOCl +95% alcohol+ 2% CHX. The teeth were split in bucco-lingual aspect and the specimens were observed using Field Emission Scanning Electron Microscope. The percentages of remaining debris and patent dentinal tubules were determined. Statistical analysis was performed with one-way analysis of variance (ANOVA). Energy Dispersive x-ray Spectroscopy was used for analyzing the occluded materials in dentinal tubule for elementary analysis. There were no significant differences in percentage of remaining debris and patent tubules between all experimental groups at all levels (p > .05). In elementary analysis, the most occluded materials in dentinal tubule were dentin debris. NaOCl/CHX precipitate was detected in one tooth specimen of Group 1. In conclusion, there were no significant precipitate on root canal, but suspected material was detected on Group 1. The irrigation system used in this study could be prevent the precipitate formation.

• Research in Plant Disease
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• v.14 no.1
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• pp.51-56
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• 2008

Powdery mildew of lettuce that is a newly reported disease became a threat to organic cultivation of lettuce in Korea since the disease caused by Podosphaera fusca resulted in a half of yield loss in heavily infected fields. To improve micro-environmental conditions around lettuce, ACF (air-circulation fan) was installed on inside roof of plastic house at 6 m intervals. The ACF increased 57% of lettuce yield and reduced 71.4% of lettuce seedling death. COY (cooking oil and yolk mixture) consisted of cooking oil 0.3% and egg yolk 0.08% reduced lettuce seedling death from 89.3% to 92.9% under the greenhouse. Seven-day interval spray of COY resulted in high control values of powdery mildew of lettuce ranging from 89.6% to 96.3%, which was comparable to a fungicide, Azoxystrobin. Lettuce yield was increased about two times compared to a non-treated conventional cultivation. Qualities of lettuce such as hardness and chlorophyll content were also improved by COY and ACF combination. Effect of COY on control of the disease was improved when $CaCO_3$ or $SiO_2$ 1,000 ppm was supplemented. Results indicated that the COY made of cooking oil such as canola emulsified with yolk was highly effective on control of powdery mildew of lettuce and suitable for organic agriculture, especially when combined with ACF.

• Korean Journal of Poultry Science
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• v.29 no.2
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• pp.141-148
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• 2002

Two experiments were conducted to investigate the effects of supplemental feather digests on the growth of broiler chicks and taurine content in the broiler meat. In experiment 1, a total of 40 broiler chickens(Ros $s_{R}$) were assigned to four dietary treatments: control(T1), regular feather meal(FM) diet(R-FM,T2), NaOH treated FM diet(NaOH-FM,T3), HNO) treated FM diet($HNO_{3}$ -FM, T4). In experiment 2, a total of 70 broiler chickens were assigned to seven dietary treatments: T1 to t4(same as those of Exp. 1), modified $HNO_{3}$ treated FM diet(M- $HNO_{3}$-FM, T5), hair meal diet(HM, T6) and 0.22% cystine supplemented diet(CYS, T7). Feather meals and hair meal were supplemented at the level of 5% in the diet. In experiment 1 and 2, weight gain of chicks frd with R-FM or NaOH-FM tended to be higher than control or $HNO_{3}$ -FM. In experiment 2, weight gain of chicks frd with CYS was the highest followed by R-FM, M-HN $O_3$-FM, NaOH-FM, control, HM and $HNO_{3}$ -FM. In experiment 1, taurine content in breast muscle of chicks fed NaOH-FM was sogmofocamtly higher(P<0.05) than control. In experiment 2, taurine content in breast muscle of chicks fed NaOH-FM and CYS tended to be higher than other groups. Taurine content in leg muscle was significantly different among treatments as NaOH-FM and R-FM being highest followed by M- $HNO_{3}$-FM, CYS, control, $HNO_{3}$ -FM and HM. Taurine content in the liver(Exp. 1 and 2) and heart(Exp. 2) were not significantly affected by the supplemental feather digests. These results indicated that 5% NaOH-FM in the diet was effective in increasing taurine content in breast and leg muscle of broiler chicks.s.

• Animal Systematics, Evolution and Diversity
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• v.14 no.4
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• pp.341-355
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• 1998

Thirty one morphometric characters of specimens in 15 subspecies of striped field mouse(Apodemus agrarius Pallas) from Eurasia were analyzed to clarify taxonomic status of these subspecies. Five major subgroups in A. agrarius were revealed: I, a largest-size form, specimens from two southern from other six localities in Korea, subspecies coreae and pallescens; III, the other large-size from, specimens from Astrachan in western Russia, subspecies volgensis; IV, a medium-size form, specimens from 16 localities in eastern Asia(North Korea, China, and eastern Russia), subspecies coreae, manchuricus, pallidior, ningpoensis, and insulaemus; V, a small-size form, specimens from 16 localities in western Asia and Europe (Kazakhstan, Russia, Lithuania, and Ukraine), subspecies tianschanicus, ognevi, agrarius, septentrionalis, nikolski, caucasicus, and karelicus. From this morphometric analyses, the followings are concluded: subspecies chejuensis is a larger-size form, as noted by Johnson and Jones(1955): subspecies pallescens is the synonym of subspecies agrarius, as suggested by Koh(1986): subspecies coreae from Korea is a large-size form and is idistinct from other 12 subspecies in Eurasia: the eastern form of subspecies ningpoensis by Corbet(1978) is a medium-size form o subspecies manchuricus, pallidior, ningpoensis, and insulaemus from eastern Asia (China and eastern Russia), and it includea North Korea specimens: a small-size form from western Asia and Europe(subspecies tianschanicus, ognevi, agrarius, septentrionalis, nikolski, caucasicus, and karelicus) is the western form of subspecies agrarius by Corbet(1978); the other large-size form of subspecies volgensis from western Russia is a distinct subspecies, which differs from the western subspecies agrarius. Therefore, it is concluded that 15 subspecies of A. agrarius can be classifed into five subspecies (chejuensis, coreae, ningpoensis, agrarius, and volgensis), although it is necessary to measure and analyze morphometric characters of specimens of other seven subspecies(albostriatus, maculatus, rubens, kahmanni, henrici, gloveri, and harti) for the complete reclassification of this species).

• Korean Journal of Weed Science
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• v.15 no.2
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• pp.105-114
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• 1995

Differences in critical period of weed competition were investigated among five types of rice(Oryza sativa L.) cultivation. Increase in weed-free period resulted in 1-2 days delay of heading date in machine transplanting and direct-seeding as compared with complete weed-free plot. When weedy period increased, there was no difference in heading date in transplanting cultivations. In direct-seeding, however, weedy period of 7-10 weeks after seeding(WAS) resulted in 4-7 days delay of heading date, whereas further increase in the weedy period caused rather 5-6 days advance in heading date. Weed-free period did not significantly affect yield components in conventional hand transplanting. In machine transplanting with 30-day-old seedling decreases in percent ripening and 1,000-grain weight were caused by weeds emerged within 4 weeks after transplanting(WAT). All yield components were decreased due to weedy period in machine transplanting with 10-day-old seedling. In direct-seeding weedy periods caused to decrease in number of panicles, number of spikelets, percent ripening, and 1,000-grain weight were 8-9, 4-5, 3-4, and 8-10 WAS, respectively. The critical periods of weed competition were determined as the following. In conventional hand transplanting weed-free must be maintained for either 4 weeks after transplanting or the rest period after 8 WAT. In machine transplanting with 30-day-old seedling weed-free must keep for either 5 weeks after transplanting or the rest period after 8 WAT. In machine transplanting with 10-day-old seedling weeds must be removed for either 5 weeks after transplanting or the rest period after 7 WAT. Weed-free must be kept between 5 and 7 WAS in flood direct-seeded rice and between 6 and 9 WAS in dry direct-seeded rice.