• Korean Journal of Ecology and Environment
• /
• v.55 no.4
• /
• pp.305-319
• /
• 2022

The community temperature index (CTI) reflects the temperature and environmental preferences of the community. We investigated the distribution patterns of major aquatic insect assemblages (Ephemeroptera, Plecoptera, and Trichoptera; EPT) based on CTI in streams of South Korea. We selected unpolluted 151 study sites at upper streams(less than 3^rd) with less than 1.5 mg L^-1 of biochemical oxygen demand. Study sites were clustered into six groups based on the similarities of their EPT composition. All three orders showed a continuous decrease in the number of species as CTI increased, especially in Plecoptera. In addition, the functional feeding groups were also significantly changed according the CTI changes. Temperature tolerance range of each group's indicator species varied according to the CTI of the group. Finally, changes of CTI reflected differences of EPT assemblages according to the differences of environmental condition including temperature. Therefore, CTI can be applied to the evaluation and preservation of stream ecosystems and prediction of community changes due to climate change.

• Journal of environmental and Sanitary engineering
• /
• v.14 no.3
• /
• pp.22-30
• /
• 1999

This study was carried out to examine the compressive strength characteristics of solids solidified with the lead sludge with mixture of cement and fly ashes as additive. And the additives are commercial fly ash and ESP(Electrostatic precipitator) fly ash. The compressive strength of solidified lead sludge solid was increased by adding fly ash up to 46~62%, which was the results of pozzolanic reaction. When replaced the cement with 10%of commercial fly ash, the solid showed the highest value $210{\;}kg/cm^2$, and the solidification conditions were 0.55 of the water/cement ratio and curing for 14 days. Also, the results of leaching test by EPT(Environmental Protection Agency-Toxicity Test) were showed that the solidified lead has leached out under 10%, which was less than 0.173 mg/L of EPA standard. As leaching solutions, the demineralized water, 0.1N acetic acid solution, and synthetic brine were used. and the observations by SEM of the solidified lead-laden solid after EPT leaching test were indicated the severe erosion on solid surface.

• 한국신재생에너지학회:학술대회논문집
• /
• 2007.06a
• /
• pp.737-741
• /
• 2007

This paper analyses the environmental effect of 100kw PV system installed in Tibet using Life Cycle Assessment(LCA). Then, energy payback time(EPT) and life-cycle $CO_2$ emission rate are estimated based on life-cycle of the PV system. As a result of the estimation, 6 year of EPT and 20 g-C/kWh of $CO_2$ emission rate are obtained. In China, average $CO_2$ emission rate of fossil fuel power generation plant is 260 g-C/kWh. This shows that PV system would be very promising for global environmental issues. For advanced LCA, we need to collect detailed and various data about raw material of PV system.

• New & Renewable Energy
• /
• v.3 no.2 s.10
• /
• pp.11-16
• /
• 2007

This paper analyses the environmental effect of 100kw PV system installed in Tibet using Life Cycle Assessment(LCA). Then, energy payback time(EPT) and life-cycle CO2 emission rate are estimated based on life-cycle of the PV system. As a result of the estimation, 6 year of EPT and 20 g-C/kWh of CO2 emission rate are obtained. In China, average CO2 emission rate of fossil fuel power generation plant is 260 g-C/kWh. This shows that PV system would be very promising for global environmental issues. For advanced LCA, we need to collect detailed and various data about raw material of PV system.

• Atmosphere
• /
• v.22 no.4
• /
• pp.483-488
• /
• 2012

The monsoon front lies on East Asian region, but it gradually propagates to the north during the boreal summer. The equivalent potential temperature (EPT) reveals the thermodynamical features of air masses and monsoon front. Therefore, this study considered the thermodynamical EPT and dynamical wind fields to clarify the peculiarity of East Asian summer monsoon (EASM) variations in June and July, respectively. Western North Pacific subtropical high (WNPSH) and Okhotsk sea high (OSH) both play the crucial role to interannual variations of EASM frontal activity and amount of rainfall. The OSH is important in June, but the WNPSH is key factor in July. Furthermore, the OSH (June) is affected by North Atlantic tripolar sea surface temperature (SST) pattern and WNPSH (July) is influenced by North Indian Ocean SST warming.

• Korean Journal of Child Studies
• /
• v.18 no.2
• /
• pp.73-85
• /
• 1997

The purpose of the present study was to examine the role of semantic and syntactic knowledge in the first language acquisition of Korean classifiers. The elicited classifiers production test(EPT) was conducted to 105 children aged from 2 to 7. EPT consisted of 16 classifiers and two items for each classifier. 32 items were divided into 2 major semantic features: animacy and inanimacy. The semantic features of inanimacy were subcategorized into 3 features such as neutral, shape and function. The results revealed that; 1) children produced the correct structure of classification from the very early age with correct word order of the noun phrase showing early fundamental syntactic knowledge; 2) The earliest response pattern was to respond to all nouns in the same way using a neutral classifier showing no apparent semantic basis for their choice; 3) Children didn't show any preference for animate, shape, or function classifiers.

• Proceedings of the Korea Society of Design Studies Conference
• /
• 2004.05a
• /
• pp.292-293
• /
• 2004

• 대한치주과학회:학술대회논문집
• /
• 2001.12a
• /
• pp.96-96
• /
• 2001

• Korean Journal of Environmental Biology
• /
• v.26 no.1
• /
• pp.47-55
• /
• 2008

The benthic macroinvertebrates of stream around Mt. Innae, Mt. Gumi and Mt. Dodung in Daegu were studied between April and September in 2005. Physico-chemical factors such as depth, velocity, pH, conductivity and DO were measured in each study site. The depth distributed from 3.3 cm to 18.6 cm, conductivity from 35.5 to 223.1${\mu}s$, and DO between 5.66 and 10.73$mgL^{-1}$. Total observed species of benthic macroinvertebrates were 78 in study streams. The first dominant family was Chironomidae, occupying from 59 to 65%. The other dominant families were Ephemeroptera (12$\sim$19%) and Gastropoda (5$\sim$14%). Mt. Innae was observed as having the most abundance species. EPT (Ephemeroptera, Plecoptera, Trichoptera) richness were from 4 to 14.

• Korean Journal of Materials Research
• /
• v.10 no.1
• /
• pp.15-20
• /
• 2000

The hydrogen-storage properties of a mechanically-alloyed Mg-18wt.%Ni mixture were investigated. Among the mixtures mechanically alloyed for 1h, 3h, and 6h, the mixture mechanically alloyed for 6h(MA 6h sample) shows the best properties of activation, hydriding, and dehydriding. The $Mg_2Ni$ phase forms in the mechanically-alloyed Mg-18wt.%Ni mixture along with hydriding-dehydriding cycling. The MA 6h sample is relatively easily activated and has higher hydriding rate than the pure Mg, the Mg-10wt.%Ni alloy, and a little lower hydriding rate than the $Mg_2Ni$alloy. The MA 6h sample lower dehydriding rate than the $Mg_2$Ni alloy but higher dehydriding rate than the pure Mg and the Mg-25wt.%Ni alloy. The MA 6h sample has larger hydrogen-storage capacity than the pure Mg and the other alloys.