• Journal of the Korean Geographical Society
• /
• v.41 no.5 s.116
• /
• pp.527-544
• /
• 2006

This study provides a definition of heat waves, which indicate the conditions of strong sultriness in summer, appropriate to Korea and intends to clarify long term(1973-2006) averaged spatial and temporal patterns of annual frequency of heat waves with respect to their intensity. Based on examination of the Korean mortality rate changes due to increase of apparent temperature under hot and humid summer conditions, three consecutive days with at least $32.5^{\circ}C,\;35.5^{\circ}C,\;38.5^{\circ}C,\;and\;41.5^{\circ}C$ of daily maximum Heat Index are defined as the Hot Spell(HS), the Heat Wave(HW), the Strong Heat Wave(SHW), and the Extreme Heat Wave(EHW), respectively. The annual frequency of all categories of heat waves is relatively low in high-elevated regions or on islands adjacent to seas. In contrast, the maximum annual frequency of heat waves during the study period as well as annual average frequency are highest in interior, low-elevated regions along major rivers in South Korea, particularly during the Changma Break period(between late July and mid-August). There is no obvious increasing or decreasing trend in the annual total frequency of all categories of heat waves for the study period However, the maximum annual frequencies of HS days at each weather station were recorded mainly in the 1970s, while most of maximum frequency records of both the HW and the SHW at individual weather stations were observed in the 1990s. It is also revealed that when heat waves occur in South Korea high humidity as well as high temperature contributes to increasing the heat wave intensity by $4.3-9.5^{\circ}C$. These results provide a useful basis to help develop a heat wave warning system appropriate to Korea.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.35 no.3
• /
• pp.567-577
• /
• 2015

Climate and land use changes have impact on availability water resource by hydrologic cycle change. The purpose of this study is to evaluate the hydrologic behavior by the future potential climate and land use changes in Anseongcheon watershed ($371.1km^2$) using SWAT model. For climate change scenario, the HadGEM-RA (the Hadley Centre Global Environment Model version 3-Regional Atmosphere model) RCP (Representative Concentration Pathway) 4.5 and 8.5 emission scenarios from Korea Meteorological Administration (KMA) were used. The mean temperature increased up to $4.2^{\circ}C$ and the precipitation showed maximum 21.2% increase for 2080s RCP 8.5 scenario comparing with the baseline (1990-2010). For the land use change scenario, the Conservation of Land Use its Effects at Small regional extent (CLUE-s) model was applied for 3 scenarios (logarithmic, linear, exponential) according to urban growth. The 2100 urban area of the watershed was predicted by 9.4%, 20.7%, and 35% respectively for each scenario. As the climate change impact, the evapotranspiration (ET) and streamflow (ST) showed maximum change of 20.6% in 2080s RCP 8.5 and 25.7% in 2080s RCP 4.5 respectively. As the land use change impact, the ET and ST showed maximum change of 3.7% in 2080s logarithmic and 2.9% in 2080s linear urban growth respectively. By the both climate and land use change impacts, the ET and ST changed 19.2% in 2040s RCP 8.5 and exponential scenarios and 36.1% in 2080s RCP 4.5 and linear scenarios respectively. The results of the research are expected to understand the changing water resources of watershed quantitatively by hydrological environment condition change in the future.

• Journal of Life Science
• /
• v.15 no.2 s.69
• /
• pp.225-230
• /
• 2005

The aim of this study was to examine the fluctuation in phytoplankton assemblages with regarding to environmental conditions and nutrients, which were surveyed quarterly over the fours seasons (February, May, July, and October). In turn, an understanding of biological effects should provide insights into a wide range of initiated Cochlodinium blooms in Narodo. Sampling was carried out throughout 2001 on the coasts of Busan (St. 1), Yeosu (St. 2), Narodo (St. 3), Kohung (St. 4), and Kwangdo (St. 5). The maximum surface water temperature was recorded in July, and it ranged from 20 to $22^{\circ}C$. Salinity showed no great variation, which maintained itself in the range of 29-34 psu. The maximum surface salinity was recorded in February, which was about 34 psu. The chlorophyll $\alpha$ concentration of the surface water ranged from 0.01 to $1.3\;{\mu}g\;1^{-1}$. The concentrations of $NH_{4}-N $ were persistently high from February to October; in particular, the peak was observed at St. 1 in February and May (0.15 and $0.19\;{\mu}mol\;1^{-1}$, respectively), while it was detected at St. 2 in July and October (0.22 and $2.2\;{\mu}mol\;1^{-1}$ respectively). Similar trends to those for $NH_4-N $ were observed in the concentrations of $NO_{2}-N$ and $NO_{3}-N$. In contrast to nitrogen, a distinct peak of $NO_{4}-P$ at St. 3, 4, and 5 was observed throughout year $(0.01-0.1\;{\mu}mol\;1^{-1}$ except for October. At St. 1 encounter a peak of cell number of 30,000 and $13{\times}10^3$ cells $1^{-1}$, respectively, in July and October. During the period of this study, the majority of the taxa were diatoms. The dinoflagellates were rather abundant after February, in particular at St. 3, 4, and 5 which attained an abundance of $10\~20\%$without marked fluctuation during the period of this study. At St. 3, the highest average cell width, $178.11\;{\mu}m$, was recorded: the highest cell length, $337.72\;{\mu}m$, was measured in July. Consequently, dinoflagellates bloom in July at Narodo influenced by warm water current are not only associated with a desirable development of cell morphometric characteristics, but also with the health growth of C. polykrikoides. During the period of this study, warm water currents caused an increased water temperature in Narodo, but did not change the amount of nutrients.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.37 no.7
• /
• pp.826-833
• /
• 2008

The effects of porphyran-chungkookjang on cytotoxicity of human normal cell line (BJ) and human cancer cell lines (AGS and HT-29) were examined. Porphyran, which was prepared from laver (Porphyra yezoensis), decreased the viability of the cancer cells, however, it did not affect the viability of normal cells. Porphyranchungkookjang was prepared by the addition of 5% (w/w) porphyran into chungkookjang which was fermented by starter, Bacillus subtilis DJI. The cytotoxicity effects of the chungkookjang and porphyran-chungkookjang were evaluated with MTT assay. The methanol and the water extract of porphyran-chungkookjang at 1.0 mg/mL showed $23{\sim}38%$ decreases in proliferation of cancer cells (AGS and HT-29). However, the methanol and the water extracts of porphyran-chungkookjang did not inhibit the growth of normal cell. Moreover, the methanol extract of porphryan-chungkookjang at 1.0 mg/mL showed $1.2{\sim}1.5$ fold higher anticancer effects than that of the chungkookjang.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.7 no.3
• /
• pp.192-200
• /
• 2005

This study was conducted to investigate inorganic nutrient contents in spur leaf and shoot leaf of 'Niitaka' pear during the growing season and leaf inorganic nutrient contents as influenced by meteorological elements. The contents of N, P, K, and Mg were decreased in spur leaf during their vegetative growth, while Ca and Mn increased. The contents of N, P, K, Mg, and Fe showed no differences between spur leaf and shoot leaf. However Ca, Mn, Zn, and Cu contents were higher in spur leaf than those in shoot leaf, but B content was lower in spur leaf than those in shoot leaf. The content of N in shoot leaf was positively correlated with mean temperature, whereas negatively correlated with maximum temperature. The content of P in spur leaf was negatively correlated with maximum temperature. The content of Ca in spur leaf was negatively correlated with mean temperature, whereas positively correlated with maximum and minimum temperature. The contents of Mg and B in shoot and spur leaf were positively correlated with mean temperature, whereas negatively correlated with maximum and minimum temperature. The contents of Ca and Mn showed significant differences between spur leaf and shoot leaf at mid-July to early August. These results suggest that sampling is important to distinguish between spur leaf and shoot leaf for diagnosis of nutrient conditions in pear trees.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.11
• /
• pp.740-745
• /
• 2020

To calculate the reasonable design temperature load of a concrete box girder bridge, one bridge test specimen was made. The temperature gauges installed on the bridge test specimen measured 48 sets of temperature per day at 30-minute intervals during the summer and winter periods of one year. The temperature measured at each station was treated statistically to calculate the trend line and standard error, and the temperature distribution and trend line at the representative station were presented. The maximum effective temperature and the lowest effective temperature were calculated from the air temperature suggested by Euro code. The maximum effective temperature was calculated to be 1.5 to 2℃ higher than the Euro code at 35℃ and above. In comparison, the lowest effective temperature was 0.5 to 1.1℃ lower at -13℃ to-19℃. Compared to the effective temperature of this study according to the highest and lowest 50-year frequency of the Yangsan region, the highest effective temperature was 4.7℃ higher, and the lowest effective temperature was 4.5℃ lower. Considering the increasing climate change and reflecting the results of this analysis, it is deemed necessary to make the current temperature design standards larger.

• The Journal of the Korea Contents Association
• /
• v.10 no.8
• /
• pp.257-265
• /
• 2010

The purpose of this study was to investigate the effect of different ramp inclination on the maximum plantar foot pressure and pathway of the center of pressure. Fifteen healthy adults who had no musculoskeletal disorders were participated with this study and descended the ramp with different inclination(level, $-5^{\circ}$, $-10^{\circ}$, $-15^{\circ}$). Plantar foot pressures were recorded by the Matscan system(Tekscan, Boston, USA) during level and descending ramp with barefoot. Plantar foot surface was defined as seven regions for pressure measurement; two toe regions, three forefoot regions, one midfoot region, one heel region. Repeated ANOVA was used to compare each region data of foot according to different ramp inclination. As descending ramp inclination became increased, the pressure of hallux region was significantly increased at $-15^{\circ}$ inclination and the pressure of 2-3 metatasal head region were significantly decreased at $-5^{\circ}$, $-10^{\circ}$, $-15^{\circ}$ inclination. The pathway of COP had a tendency to be shifted inside in forefoot and prolonged to great toe as the descending ramp inclination increased. The results indicated that plantar foot pressure could be changed at hallux and forefoot regions with $-5^{\circ}$ ramp inclination and these findings demonstrated that ramp inclination could affect the structure and function of foot.

• KSBB Journal
• /
• v.23 no.1
• /
• pp.70-76
• /
• 2008

Surface of hydrophobic media was modified to become hydrophilic by ion beam irradiation. Fixed bed biofilm reactors packed with or without surface modification were used to remove organics, nitrogen, and phosphorus from sewage. This system composed of anoxic/oxic cycles to increase the nutrient removal. A cylindrical polyethylene was used as a packing media in this study. With 12 hours of hydraulic retention time (HRT), the reactors with and without surface modification showed 95% and 92% $COD_{cr}$ removal, respectively. Both reactors showed over 95% $COD_{cr}$ removals for a longer HRT of 16 hours. Nitrogen removal ranged 54.8% to 70.2% for the surface modified system and 57.5% to 76.5% for the non-modified system under same condition. Finally, phosphorus removal ranged 59.4% to 69.8% for the surface modified system and 51.3% to 63.4% for the non-modified system under same condition. From this study organics and phosphorus were better removed in using surface modified media and vice versa for nitrogen removal.

• Applied Chemistry for Engineering
• /
• v.5 no.2
• /
• pp.199-208
• /
• 1994

In this study, the ultrasound which provides the properties of mixing, and surface cleaning effect, the increase of the effective reaction surface area and the enhancement of the effective collision frequency, was used to enhance the recovering efficiency of Cu from the Cu-ion containning waste water. The ultrasonic reactor used in this study was designed and constructed for improving the disadvantage of the existing ultrasonic reactor. From the experimental result and its analysis, we obtained following conclusions. 1. The ultrasound increased the rate of electrochemical deposition to 582.2% in maximum at the condition of $0.1M-CuSO_4$, and 2.1 V-overpotential. 2. The enhancement effect of ultrasound induced by the reduction of diffusion layer thickness was 277.8% in maximum and induced by the other effect except for the reduction effect of the diffusion layer thickness was 253.6% in maximum at $0.1M-CuSO_4$ and 2.1V overpotential. 3. This study gave the possibility of the scale-up of ultrasonic reactor and in particular, ultrasonic reactor would be effective in the treatment of waste water containning a low concentration of Cu ion.

• Journal of Animal Science and Technology
• /
• v.55 no.3
• /
• pp.173-178
• /
• 2013

The characteristics of lactation persistency was investigated for new evaluation trait using 4,366,900 milk yield records from 436,690 heads of Korean Holstein dairy cattle. The average lactation persistencies of first parity, second parity and over third parity were 97.5%, 95.1% and 94.6%, respectively and there was a trend that after the peak yield, lactation persistency decreased collectively. The average days of peak milk yields after calving was about 50 days, but only 33.2% of cows reached peak yields at 36~66 days (second test day). Also, there was a difference between the milk yield of cows which reached peak yields at first test day by lactation days and that of cows which reached peak yields at second to fourth test day. The estimates of heritabilty and repeatability for mean lactation persistency were 0.16 and 0.35, respectively. The genetic correlation between cumulative lactation persistency from third to tenth test day and that from third to seventh test day was 0.91 and while it increased in later test day, it decreased sharply in earlier test day. The breeding value correlations of Data II and III for Data I were 0.80 and 0.72, respectively, while the rank correlations were 0.78 and 0.71, respectively. Based on the results, the breeding value and rank correlations decreased when more data were added.