• Journal of Korean Society of Forest Science
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• v.109 no.1
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• pp.31-40
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• 2020

This study aimed to investigate the effects of climate change on the survival and growth performance of Pinus densiflora and Larix kaempferi seedlings using open-field experimental warming and precipitation manipulation. We measured the survival rate, root-collar diameter, and height, and then calculated the seedling quality index (SQI) of 2-year-old seedlings under 6 treatments [2 temperatures (TC: Control; TW: Warming) × 3 precipitation manipulations (PC: Control; PD: Decreased; PI: Increased)] and performed a two-way ANOVA to test for differences.The air temperature of the warming plots was 3℃ higher than that of the control plots, while the precipitation manipulation plots received ±40% of the precipitation received by the control plots. Temperature and precipitation treatments did not significantly affect the survival rate of P. densiflora; however, the SQI of P. densiflora decreased with increasing precipitation. In contrast, the mortality rate of L. kaempferi increased with increasing temperature and decreasing precipitation. Furthermore, in L. kaempferi, TC × PI treatment resulted in the lowest SQI with a significant interaction effect observed between the two factors. In summary, low seedling production and quality should be expected in P. densiflora as precipitation increases and in L. kaempferi as temperature increases or precipitation decreases. These results indicate species-specific sensitivities to climate change of two plant species at the nursery stage. With the occurrence of global warming, the frequencies of drought and heavy rainfall events are increased, and this could affect the survival and seedling quality of tree species. Therefore, it is necessary to improve nursery techniques by establishing new adaptation strategies based on species-specific growth performance responses.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.6
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• pp.17-27
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• 2012

Climate is generally accepted as one of the major determinants of plants distribution. Plants are sensitive to bioclimates, and local variations of climate determine habitats of plants. The purpose of this paper is to identify the factors affecting the distribution of narrow-range plants in South Korea using National Survey of Natural Environment data. We developed species distribution models for 6 plant species using climate, topographic and soil factors. All 6 plants were most sensitive to climatic factors but less other factors at national scale. Meliosma myriantha, Stewartia koreana and Eurya japonica, distributed at southern and coast region in Korea, were most sensitive to precipitation and temperature. Meliosma myriantha was mostly effected by annual precipitation and precipitation of driest quarter, Stewartia koreana was effected by annual precipitation and elevation, and Eurya japonica was affected by temperature seasonality and precipitation of driest quarter. On the other hand, Spiraea salicifolia, Rhododendron micranthum and Acer tegmentosum, distributed at central and northern inland in Korea, were most sensitive to temperature and elevation. Spiraea salicifolia was affected by mean temperature of coldest quarter and annual mean temperature, Rhododendron micranthum and Acer tegmentosum were affected by mean temperature of warmest quarter and elevation. We can apply this result to future plant habitat distribution under climate change.

• Journal of Korean Society of Forest Science
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• v.107 no.1
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• pp.43-49
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• 2018

This study was conducted to investigate the effects of warming and precipitation manipulation on seasonal changes in fine root production (FRP) and fine root mortality (FRM) of 33-month-old Pinus densiflora seedlings for two years. The seedlings in warmed plots were warmed with $3.0^{\circ}C$ higher using infrared heaters. The air temperature of warmed (TW) plots was set to increase by $3^{\circ}C$ compared to temperature control (TC) plots, and the three precipitation manipulation consisted of precipitation decrease (-30%; PD), precipitation increase (+30%; PI) and precipitation control (0%; PC). FRP ($mm\;mm^{-2}\;day^{-1}$) was significantly altered by only precipitation manipulation (PC: 3.57, PD: 4.59, PI: 3.02), while warming had no significant effect on the FRP and FRM. Meanwhile, interactions between warming and precipitation manipulation and seasonal changes had no significant effects on FRP and FRM. However, the influences of seasonal changes in soil temperature and soil moisture on FRP and FRM were different according to warming. In TW plots, FRP showed a positive relationship with soil temperature, and FRM showed a negative relationship with soil moisture. On the other hand, in the TC plots, FRP showed a positive relationship with soil moisture, and there were no relationships between FRM and soil temperature and moisture. These results indicate that the climate factors that affect FRP and FRM might vary as the warming progresses.

• The Journal of the Society of Stroke on Korean Medicine
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• v.9 no.1
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• pp.8-13
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• 2008

Objectives : This study was to investigated the correlation between average temperature & precipitation and pattern identification of the patients with stroke. Methods : 115 stroke patients within 30days of onset were registered during the study period. Pattern identification of stroke was classified into Fire and heat, Turbid phlegm and others. We took the mean of average temperature according to pattern identification and analyzed pattern identification into two groups according to climatological normal of average temperature in Seoul. We also analyzed pattern identification into two groups according to existence of precipitation. Results : Heat and fire, and other type of pattern identification had high frequency when average temperature was higher than 12.2℃. And there was no correlation between precipitation and pattern identification of stroke.

• Journal of the Korean Society for Heat Treatment
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• v.34 no.5
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• pp.226-232
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• 2021

The relationship between precipitation and coefficient of thermal expansion of Al-6%Si-0.4%Mg-0.9%Cu-(Ti) alloy (in wt.%) after various heat treatments were studied by the thermodynamic analyzer (TMA) and differential scanning calorimetry (DSC). Solution heat treatment of the alloy was carried out at 535℃ for 6 h followed by water quenching, and the samples were artificially aged in the air at 180℃ and 220℃ for 5 h. The coefficient of thermal expansion (CTE) curve showed some residual strain and decreased with increasing aging temperature. The CTE curves changed sharply in the temperature range of 200℃ to 400℃, and the corresponding peak shifted for the aged samples due to the change in the precipitation behavior of the secondary phase. These transformation peaks in the aged sample are related to the volume of the precipitation of the Si phase as determined by DSC analysis. The change in CTE is mainly caused by the precipitation of the Si phase in the Al-Si alloy, and the size of the change occurs simultaneously with the size of the precipitate.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.992-996
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• 2008

In this study, changes in precipitation across South Korea during snow seasons (November-April) and their potential are examined. Current (1973/74-2006/07) and future (2081-2100) time series of snow indices including snow season, snow-to-precipitation ratio, and snow impossible day are extracted from observed snow and precipitation data for 61 weather stations as well as observed and modeled daily temperature data. Analyses of linear trends reveal that snow seasons have shortened by 3-13 days/decade; that the snow-to-precipitation ratio (the percentage of snow days relative to precipitation days) has decreased by 4-8 %/decade. These changes are associated with pronounced formations of a positive pressure anomaly core over East Asia during the positive Arctic Oscillation winter years since the late 1980s. A snow-temperature statistical model demonstrates that the warming due to the positive core winter intensifies changes from snow to rain at the rate of $4.7cm/^{\circ}C$. The high pressure anomaly pattern has also contributed to decreases of air-sea thermal gradient which are associated with the reduction of snow could formation. Modeled data predict that a fingerprint of wintertime global warming causing changes from snow to rain will continue to be observed over the 21st century.

• Journal of the Korean earth science society
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• v.27 no.2
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• pp.188-197
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• 2006

The characteristics of variability of temperature and precipitation in Jeju were investigated using data observed in Jeju station for from 1924 to 2004. Annual mean temperature change for the last 81 years is $0.02^{\circ}C$ increase per year. After 1980, the increase is $0.05^{\circ}C$ per year, larger than the former. The increase of the minimum temperature is larger than that of the maximum temperature in Jeju and has resulted in the increase of mean temperature. The frequency of climate extreme occurrence of temperature and rainfall was also investigated. The temporal variation of frequency of the extremely higher temperature has increased in the 1980's with global warming. The appearance of the extremely lower minimum temperature has decreased during the summers and winters. The facts that the frequencies of rainy days has decreased and heavy rainfall days of more than 80 mm per day in precipitation has increased indicate the increase of rainfall intensity.

• Journal of Ginseng Research
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• v.8 no.1
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• pp.65-74
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• 1984

This experiment was carried out to study the effects of light intensity and soil water regimes on the growth of ginseng seedling. The results were as follows: 1. The maximum light intensity and optimum temperature in 1,le photosynthesis of ginseng seedling were 10,000 lux and 23 $^{\circ}C$. Respiration rate was increased at high temperature. 2. Air and soil temperature under the shading were increased as the increase of light intensity but soil water contents were decreased as the increase of light intensity, whereas air and soil temperature were decreased as the increase of precipitation under the shade b5: soil water contents were increased as the increase of precipitation under the shade. 3. The higher the transmittance of the shade, the greater the specific leaf weight (S.L.W.) and stomatal density. In contrast, however, the contents of total chlorophyll, chlorophyll a and b, and stomatal length was decreased. There was no any significant difference light intensity of the a/b ratio of chlorophyll. 4. The highest photosynthesis was occurred in ginseng leaves grown under the shade 5% L.T.R. and net photosynthesis rates increased with increasing soil water contents. 5. Optimum condition for usable seedling yield were 5% L.T.R. and 3.3% precipitation under the shade. Useless seedling increased with increasing precipitation under the shade.

• Journal of the Korean Ceramic Society
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• v.34 no.12
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• pp.1247-1253
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• 1997

Sinter-active yttria powders were prepared by a solution precipitation with using a self-decomposing precipitation agent NH2CONH2(urea). The cold-pressed powders can be sintered to full density and the microstructure of grains less than 200 nm at a temperature as low as 120$0^{\circ}C$. The activity of the yttria powder has been controlled by varying nucleation conditions during precipitation and by minimizing formation of aggregates. The type of precursor is decisive in preparation of a sinter-active oxide powder, and urea is desirable as a precipitation agent for an active yttrium oxide powder.

• Spatial Information Research
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• v.16 no.4
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• pp.467-478
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• 2008

This study analyzes the spatial and temporal variability of temperature ($^{\circ}C$) and precipitation (mm) in Seoul, Korea. The temperature and precipitation data were measured at 31 automatic weather stations (AWSs) in Seoul for 10 years from 1997 to 2006. In this study, inverse distance squared weighting (IDSW) was applied to interpolate the non-measured spaces. To estimate the temperature and precipitation variability, the mean values and frequencies of hot and cold days were examined. The maximum and minimum temperatures were $32.80^{\circ}C$ in 1999 and $-19.94^{\circ}C$ in 2001, respectively. The year 2006 showed the highest frequency of hot temperatures with 79 hot days, closely followed by 2004 and 2005. The coldest year was in 2001 with 105 cold days. The annual mean temperature and precipitation increased by about $1^{\circ}C$ and 483mm during the 10-year period, respectively. The temperature variability differed between high-elevation forested areas and low-elevation residential areas. However, the precipitation variability showed little relation with the topography and land use patterns.