• Journal of the Korean Geographical Society
• /
• v.37 no.4
• /
• pp.385-402
• /
• 2002

This study examined temporal and spatial patterns of bioclimatic perceived sultriness in South Korea by analyzing the climatology of heat index calculated from ambient temperature and relative humidity for the period of 26 years (1973-1998). As results, spatially, bioclimatic sultriness above all thresholds frequently occurred mainly in the central western inner area, the southwestern inner area, and the southeastern inner area of South Korea. Especially, Miryang in the southeastern inner area of South Korea was proved to be, bioclimatically, the sultriest area in South Korea that has recorded frequent high heat index. Temporally, frequency of sultriness in the contiguous South Korea significantly increased in the 1990s. Specifically, In 1994, frequencies of heat index exceeding each threshold was the highest all over South Korea. Normally, the sultriness with high heat index exceeding 40.6$^{circ}C$ occurred mainly for the period of between the end of July generally after Summer Changma and the beginning of August before another small rainy season of years. These temporal-spatial distributions of bioclimatic sultriness in South Korea showed various patterns regionally, affected by physical and anthropogenic climatic factors such as topography, latitude, altitude, water bodies or aforestration, urbanization, and industrialization as well as movements of large-scale air masses.

• Textile Coloration and Finishing
• /
• v.27 no.1
• /
• pp.70-79
• /
• 2015

To establish the optimal conditions for the manufacture of high absortive cellulose film(CF) originated from Styela clava tunic(SCT), the physicochemical properties included absorption was measured in CFs prepared under the various conditions. The highest absorption was observed for SCT-CF20 prepared from the cellulose solution dissolved at $80^{\circ}C$ for 20min, although the filtration treatment did not induce any significance alteration. Also, the absorption was higher in SCT-CF20-F prepared by the freeze drying than SCT-CF20-N(ambient air drying) and SCT-CF20-H(heat drying). The addition of porogen($NaHCO_3$) induced an increase of absorption in SCT-CF20-PF relative to SCT-CF20-F, while the number of interconnected porous structures was enhanced in SCT-CF20-PF. Furthermore, a high level of SK-MEL-2 cells viability was observed in SCT-CF20-PN and SCT-CF20-PF cultured group. These results show that SCT-CF may have high absorption and biocompatibility when prepared from SCT cellulose solution dissolved at $80^{\circ}C$ for 20min after addition of porogen and then subjected to freeze drying.

• The Korean Journal of Pesticide Science
• /
• v.14 no.4
• /
• pp.401-406
• /
• 2010

This study was conducted to investigate the control effects of the environmental-friendly materials against major diseases of pear and to elucidate factors related to spore disperse of pear scab and pear rust. Spore disperse was deeply related ambient temperature in the early stage of disease occurrence and the maximum spore disperse was affected greatly by the air humidity, Percent of infected leaves of pear scab in plot treated with Trichoderma harzianum-YC459 was 29.3% and 43.3% in plot treated with Sulfur-80%. Two formulations above-mentioned were less effective to control pear scab than the chemical pesticide, hexaconazole. Control effect in plots single- and mixed-treated with Trichoderma harzianum-YC459, Sulfur-80% and hexaconazole against pear scab were compared with that in plot treated with chemicals by conventional application schedule in pear orchard. The incidence of pear scab was lower in plot treated with the environmental-friendly materials than that of untreated plot. However there was no significant difference among the treatments at the 5% level. Application of Sulfur-80% reduced significantly the incidence of pear scab (7.8%) compared to that (10.3%) in plot treated by conventional application schedule in organically cultivated pear orchard. Alternative application of Trichoderma harzianum-YC459 and Sulfur-80% (4.3%) suppressed the incidence of pear rust than that (7.1%) in plot treated by conventional application schedule in organically cultivated pear orchard.

• Membrane Journal
• /
• v.21 no.2
• /
• pp.155-162
• /
• 2011

Dense tubular $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ (BSCF) membranes were prepared by extrusion technique. The phase structure of the $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ membranes was characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). Relative density of $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ tubular membrane was 94.10%. Oxygen permeation was measured at difference operating condition of feed side and permeate side in the temperature range from 700 to $950^{\circ}C$. The oxygen permeation flux of dense tubular $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ membrane reached maximum 1.37 mL/$min{\cdot}cm^2$ at $900^{\circ}C$ exposed to ambient air (feed side) and vacuum pump (permeate side).

• Journal of the Korean earth science society
• /
• v.21 no.1
• /
• pp.51-58
• /
• 2000

This study was performed to accumulate database for natural sulfur emissions in the Yellow Sea region of Korea. The atmospheric concentrations of dimethylsulfide(DMS) were measured during two intensive field experiments (April and September 1999) from Duk-Juk Island located in the Yellow Sea. Ship-measurement of DMS was made additionally between Chungdo(China) and Inchun(Korea) across the Yellow Sea during June 1999. The mean(and ISD) of DMS concentrations in Duk-Juk Island during two field campaigns was $24.0{\pm}40.5$(n=40, April) and $61.1{\pm}37.9$ pptv(n=35, September), respectively. The atmospheric DMS measured from ship experiments was generally low and close to the background concentrations in the open sea area. The temporal distributions of DMS concentration were complicated in some sense but comparable to those of ambient meteorological parameters. On the basis of our measurements of atmospheric DMS(and evidence found from previous studies), the sea-to-air flux of DMS in the Yellow Sea is estimated to be about 4Gg S/yr. This amount of natural S emissions is relatively lower than the estimates derived for Cheju Island. Therefore, additional experiments may be desperate to derive more reliable figures for natural sulfur emissions in the Yellow Sea region.

• International Journal of Highway Engineering
• /
• v.6 no.2 s.20
• /
• pp.47-59
• /
• 2004

The temperature variation of concrete pavement at early-age significantly affects the initiation and propagation of its early-age cracks. This implies that the measurement and analysis of early age temperature trend are necessary to examine the causes of early age cracks in the concrete pavement. In this study, it is investigated how the early age temperature trend in concrete pavement affects the random crack initiation and behaviors of saw-cut joints using the actual construction site which is located at the KHC test road. During 72 hours after placing the concrete pavement, the ambient air temperature and temperatures at the top, middle, and bottom in concrete pavement were measured and the random crack initiation in concrete slabs and early age behaviors in the joints were surveyed. The investigation results indicate that the first random crack was initiated at one of the slabs placed in the early morning which have higher temperature changes during early 72 hours. The movement of slab was influenced by the early-age crack in the joint. It suggested that the different occurrence time of the cracks in the joint had an influence on the behavior of the cracks. Besides, the slab constructed In the morning had higher possibility of crack initiation than that in the afternoon. The rarely occurred cracks had bigger gap than other cracks.

• Korean Journal of Soil Science and Fertilizer
• /
• v.23 no.2
• /
• pp.94-99
• /
• 1990

A field experiment was conducted to study seasonal evapotranspiration above soybean canopy and its relationship with dry matter production by the Bowen ratio-energy balance method. The soybean "Paldalkong" was sown with the space of $47{\times}10cm$ at Suwon on May 27, 1988. The daily net radiation ranged from 59 to 76 percents of the total shortwave radiation under cloudless conditions, which was lower than cloud overcast condition with recorded 63 to 83 percents. The latent heat flux under overcast condition was sometimes larger than the sum of net radiation, implying transportation of energy by advection of ambient air. The linear relationship was obtained between daily or daytime net radiation and evapotranspiration. The evapotranspiration calculated by Bowen ratio-energy balance method was about 150 percent of class A pan evaporation during the growing season. The total solar radiation from June 20 to August 27 was $1043MJm^{-2}$. The 85 percent of the total shortwave radiation was used for evaporative heat. The dry matter production within the period was $836gm^{-2}$ and the water use efficiency was $2.31gDM\;kg^{-1}\;H_2O$.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.36 no.1
• /
• pp.17-21
• /
• 1991

The study was performed to investigate the effects of gaseous emission of sulfur dioxide and hydrogen fluoride on the growth of rice plant under stressed field conditions. This study is specifically dealt with multiple effects of sulfur dioxide and hydrogen fluoride on various plant growth indicators such as leaf damage, weight of grain, panicles per hill, spikelets per panicle and percent fertility. It appears that there is a good correlation between ambient concentrations of sulfur oxides and sulfur contents found in leaves with an average correlation coefficient of 0.868 within a 1% significance level. A better multiple correlation was found between percent leaf damage and sulfur and fluorine contents found in leaf with a significance of 1% level. The correlation coefficient ranges from 0.807 to 0.978 with an average being 0.922. An evaluation of data observed has demonstrated that both panicles per hill and percent fertility are significantly affected by air pollutants. As expected, hydrogen fluorides have more effects than sulfur oxides. It is, however, interesting to note that spikelets per panicle has slightly been affected while no indication of effects on l000-grain weight has been observed. This may lead to a conclusion that a reduction in yield of rice under polluted field conditions may have more been caused by the diminution panicles per hill and percent fertility rather than by the diminution of spikelets per panicle and grain weight.

• Environmental Analysis Health and Toxicology
• /
• v.29
• /
• pp.12.1-12.8
• /
• 2014

Objectives Cohort studies of associations between air pollution and health have used exposure prediction approaches to estimate individual-level concentrations. A common prediction method used in Korean cohort studies is ordinary kriging. In this study, performance of ordinary kriging models for long-term particulate matter less than or equal to $10{\mu}m$ in diameter ($PM_{10}$) concentrations in seven major Korean cities was investigated with a focus on spatial prediction ability. Methods We obtained hourly $PM_{10}$ data for 2010 at 226 urban-ambient monitoring sites in South Korea and computed annual average $PM_{10}$ concentrations at each site. Given the annual averages, we developed ordinary kriging prediction models for each of the seven major cities and for the entire country by using an exponential covariance reference model and a maximum likelihood estimation method. For model evaluation, cross-validation was performed and mean square error and R-squared ($R^2$) statistics were computed. Results Mean annual average $PM_{10}$ concentrations in the seven major cities ranged between 45.5 and $66.0{\mu}g/m^3$ (standard deviation=2.40 and $9.51{\mu}g/m^3$, respectively). Cross-validated $R^2$ values in Seoul and Busan were 0.31 and 0.23, respectively, whereas the other five cities had $R^2$ values of zero. The national model produced a higher cross-validated $R^2$ (0.36) than those for the city-specific models. Conclusions In general, the ordinary kriging models performed poorly for the seven major cities and the entire country of South Korea, but the model performance was better in the national model. To improve model performance, future studies should examine different prediction approaches that incorporate $PM_{10}$ source characteristics.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.15 no.2
• /
• pp.58-64
• /
• 2007

As the concerns regarding global worming were increased, the pressure of greenhouse gas(GHG) emission reduction on mobile source was also increased. Carbon dioxides contribute over 90% of total GHG emission and the mobile source occupies about 20% of this $CO_2$ emission. Therefore automotive exhaust is suspected to be one of the major reasons of the rapid increase in greenhouse effect gases in ambient air. In this study, in order to investigate $CO_2$ emission characteristics from gasoline passenger cars(PC), which is the most dominant vehicle type in Korea, 106 vehicles were tested on the chassis dynamometer. $CO_2$ emissions and fuel efficiency were measured. The emission characteristics by displacement, gross vehicle weight, vehicle speed and CVS-75/vehicle speed mode were discussed. Test modes were vehicle speed modes and CVS-75 mode that have been used to develop emission factors and to regulate for light-duty vehicle in Korea. It was found that $CO_2$ emissions showed higher large displacement, heavy gross vehicle weight, low vehicle speed and CVS-75 mode than small displacement, light gross vehicle weight, high vehicle speed and vehicle speed mode, respectively. From these results, correlation between $CO_2$ emission and fuel efficiency was also determined. The results of this study will contribute to domestic greenhouse gas emissions calculation and making the national policy for climate change.