• Korean Journal of Environmental Agriculture
• /
• v.32 no.3
• /
• pp.214-223
• /
• 2013

BACKGROUND: This study focused on the development of an analytical method about dichlorprop (DCPP; 2-(2,4-dichlorophenoxy)propionic acid) which is a plant growth regulator, a synthetic auxin for agricultural commodities. DCPP prevents falling of fruits during their growth periods. However, the overdose of DCPP caused the unwanted maturing time and reduce the safe storage period. If we take fruits with exceeding maximum residue limits, it could be harmful. Therefore, this study presented the analytical method of DCPP in agricultural commodities for the nation-wide pesticide residues monitoring program of the Ministry of Food and Drug Safety. METHODS AND RESULTS: We adopted the analytical method for DCPP in agricultural commodities by gas chromatograph in cooperated with Electron Capture Detector(ECD). Sample extraction and purification by ion-associated partition method were applied, then quantitation was done by GC/ECD with DB-17, a moderate polarity column under the temperature-rising condition with nitrogen as a carrier gas and split-less mode. Standard calibration curve presented linearity with the correlation coefficient ($r^2$) > 0.9998, analysed from 0.1 to 2.0 mg/L concentration. Limit of quantitation in agricultural commodities represents 0.05 mg/kg, and average recoveries ranged from 78.8 to 102.2%. The repeatability of measurements expressed as coefficient of variation (CV %) was less than 9.5% in 0.05, 0.10, and 0.50 mg/kg. CONCLUSION(S): Our newly improved analytical method for DCPP residues in agricultural commodities was applicable to the nation-wide pesticide residues monitoring program with the acceptable level of sensitivity, repeatability and reproducibility.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.15 no.2
• /
• pp.85-101
• /
• 2013

In order to search for distribution characteristics on C4 plants at the paddy fields, uplands, orchard and roadside in South Korea, vascular plants were investigated. Flora investigation had been carried out from May 2002 to October 2006 at 241 plots. In the results of survey, the flora of these areas consist of 74 families, 231 genera and 352 species totally. The class frequencies were arranged by the order of Magnoliopsidae (255 species), Monocotyledoneae (89 species), Pteropsida (7 species) and Sphenopsida (1 species). The number of species in each investigated agricultural field types was 55 families with 203 species in paddy field, 49 families with 218 species in uplands, 44 families with 115 species in orchard and 48 families with 202 species in roadside respectiviely. Representative species compositions of these four agricultural field types were characterized by Artemisia princeps, Persicaria thunbergii in paddy field, Artemisia princeps, Erigeron annuus in upland and roadside, Commelina communis, Digitaria ciliaris in orchard, respectively. Therefore, indicative species in agricultural ecosystem was Artemisia princeps. Among the investigated 352 species, $C_4$ plants identified were 38 species, and the occurrence ratio of $C_4$ monocotyledonous plants were higher in paddy field, orchard and roadside than upland. Such differences in the occurrence ratio of $C_4$ plants under diverse agricultural field types reflect differences in environmental condition such as micro-climate, soil moisture under various agricultural fields. Dominant $C_4$ monocotyledonous plants were Digitaria ciliaris and Commelina communis, while $C_4$ dicotyledonous plants were Amaranthus mangostanus and Chenopodium album var. centrorubrum in agricultural fields. Naturalized plants were identified as 47 species and occurrence ratio were higher in upland and roadside than other agricultural field types. Among the investigated naturalized plants, $C_4$ plants were Amaranthus mangostanus and Amaranthus retroflexus. Distribution characteristics of representative $C_4$ plants in agricultural field types, revealed that the projected increase in temperature due to climate change may provide better conditions for the growth of $C_4$ plants. Thus, the necessity of long-term monitoring should be conducted on the diffusion of $C_4$ plants that may threaten influence agroecosystem in Korea.

• Journal of the Korean earth science society
• /
• v.38 no.4
• /
• pp.283-292
• /
• 2017

In this study, the empirical models were established to estimate the concentrations of surface-level $PM_{2.5}$ over Seoul, Korea from 1 January 2012 to 31 December 2013. We used six different multiple linear regression models with aerosol optical thickness (AOT), ${\AA}ngstr{\ddot{o}}m$ exponents (AE) data from Moderate Resolution Imaging Spectroradiometer (MODIS) aboard Terra and Aqua satellites, meteorological data, and planetary boundary layer depth (PBLD) data. The results showed that $M_6$ was the best empirical model and AOT, AE, relative humidity (RH), wind speed, wind direction, PBLD, and air temperature data were used as input data. Statistical analysis showed that the result between the observed $PM_{2.5}$ and the estimated $PM_{2.5}$ concentrations using $M_6$ model were correlations (R=0.62) and root square mean error ($RMSE=10.70{\mu}gm^{-3}$). In addition, our study show that the relation strongly depends on the seasons due to seasonal observation characteristics of AOT, with a relatively better correlation in spring (R=0.66) and autumntime (R=0.75) than summer and wintertime (R was about 0.38 and 0.56). These results were due to cloud contamination of summertime and the influence of snow/ice surface of wintertime, compared with those of other seasons. Therefore, the empirical multiple linear regression model used in this study showed that the AOT data retrieved from the satellite was important a dominant variable and we will need to use additional weather variables to improve the results of $PM_{2.5}$. Also, the result calculated for $PM_{2.5}$ using empirical multi linear regression model will be useful as a method to enable monitoring of atmospheric environment from satellite and ground meteorological data.

• Journal of Life Science
• /
• v.25 no.10
• /
• pp.1148-1155
• /
• 2015

Commercial complete feeds contain enough nutrients to support animal growth and it is easy to be spoiled under proper temperature and humid conditions. The aim of this study was to investigate microbiological and chemical changes on complete feed for milking cow under open-air exposure with moisture 33% at 30℃ during 15 days. pH decreased 6.29 to 4.66 and water activity decreased gradually 0.99 to 0.95. Bacteria increased 6.2×10⁶~1.6×10⁷ to 2.1×10⁹ CFU/g at 5 days and showed 10⁸ CFU/g until 15 days. Fungi increased 10³ CFU/g to 8.0×10⁴ CFU/g. During the processing of spoilage, bacteria such as Acinetobacter oleivorans, Pediococcus acidilactici, Acinetobacter oleivorans, Weissella cibaria, and Methylobacterium komagatae were identified and fungi such as Fusarium sp. and Mucor sp. were also identified. Moisture content increased until 10 days (p<0.01). Crude protein was not changed so much whereas crude fat decreased 6.0% to 5.5% (p<0.01). Crude fiber and crude ash changed 2.0~ 3.0% and 4.5~ 4.8% levels with no significance, respectively. Gross energy was not almost changed at 4,400 kcal/g. During spoilage, lactate and propionate increased whereas acetate was not detected. Protease and lipase activities increased significantly during spoilage (p<0.01). Zearalenone content increased 59.2 μg/kg to 623.8 μg/kg, showing 10.5 times more production. During feed spoilage, pH decreased with microbial growth and various chemical changes were occurred.

• Journal of the Korea Institute of Building Construction
• /
• v.9 no.5
• /
• pp.79-86
• /
• 2009

In a steel structure, spray-applied fire resistive materials are crucial in preventing structural strength from being weakened in the event of a fire. The quality control of such materials, however, is difficult for manual workers, who can frequently be in short supply. These skilled workers are also very likely to be exposed to environmental hazards. Problems with construction work such as this, which are specifically the difficulty of achieving quality control and the dangerous nature of the work itself, can be solved to some degree by the introduction of automated equipment. It is, however, very difficult to automate the work process, from operation to the selection of a location for the equipment, as the environment of a construction site has not yet been structured to accommodate automation. This is a fundamental study on the possibility of the automation of spray-applied fire resistive coating work. In this study, the linkability of the cutting-edge RTLS to an automation system is reviewed, and a scenario for the automation of spray-applied fire resistive coating work and system composition is presented. The system suggested in this study is still in a conceptual stage, and as such, there are many restrictions still to be resolved. Despite this fact, automation is expected to have good effectiveness in terms of preventing fire from spreading by maintaining a certain level of strength at a high temperature when a fire occurs, as it maintains the thickness of the fire-resistive coating at a specified level, and secures the integrity of the coating with the steel structure, thereby enhancing the fire-resistive performance. It also expected that if future research is conducted in this area in relation to a cutting-edge monitoring TRS, such as the ubiquitous sensor network (USN) and/or building information model (BIM), it will contribute to raising the level of construction automation in Korea, reducing costs through the systematic and efficient management of construction resources, shortening construction periods, and implementing more precise construction

• Journal of Plant Biotechnology
• /
• v.33 no.1
• /
• pp.33-37
• /
• 2006

Bottle gourd (Lagenaria siceraria Standl.) has been used as a rootstock for the watermelon cultivation because of better growth ability at low temperature and avoidance from contamination of the soil disease. Since the genetic source for the elite rootstock is limited in nature, the genetic engineering method is inevitable to develop new lines especially to obtain the functionally important or multi-disease resistant bottle gourd. Recently, our lab has set up a successful system to transform the bottle gourd. in order to monitor the transformation process, GFP gene is used. Cotyledons of the inbred line 9005, 9006 and G5 were used to induce the shoot under the selection media with MS + 30 g/L sucrose + 3.0 mg/L BAP + 100 mg/L kanamycin + 500 mg/L cefotaxime + 0.5 mg/L $AgNO_3$, pH 5.8. The shoot was developed from the cut side of the explants after 3 weeks on the selection media. The shoot was incubated in the rooting media with 1/2 MS + 30 g/L sucrose + 0.1 mg/L IAA + 50 mg/L kanamycin + 500 mg/L cefotaxime, pH 5.8 and moved to pot for acclimation. Although the shoot development rate was depended on the genotype, the G5 was the best line to be transformed. Monitoring GFP expression from the young shoot under microscope could make the selection much easier to distinguish the transformed shoot from the non-transformed shoots.

• Journal of the Korean Vacuum Society
• /
• v.18 no.3
• /
• pp.197-202
• /
• 2009

The long term stability of ion current of QMS has been one of key parameters for monitoring gas process in vacuum. The time dependence of ionic current was monitored while the pressure of nitrogen gas was kept at a fixed pressure by introducing the gas into vacuum chamber. The chamber was evacuated to ${\sim}3{\times}10^{-9}\;Torr$ to reduce background signals before the measurement. Two ion sources were tested; one had brownish or black color due to gas contamination and the other one was new, i.e. cleaner. At a nitrogen pressure of $1{\times}10^{-5}\;Torr$, the ionic currents measured by the contaminated ion source decreased faster with time. The decrease rate was respectively ${\sim}46%$ for cleaner one and ${\sim}84%$ for contaminated one after ${\sim}5.5%$ hours. In order to test the effect of filament material on the ion current decrease, we fabricated a tungsten(W) filament which consisted of two parts; one half was made of W and the other was coated with yttria. The similar decrease of ionic currents were shown for the two types of filaments, indicating that slight change of temperature of filament due to material difference i.e. baking effect could not improve the origin of ionic current decrease. Overall the decreasing rate of ionic current is more closely associated with contaminated ion source of QMS rather than its filament materials.

• Journal of the Korean earth science society
• /
• v.35 no.1
• /
• pp.1-18
• /
• 2014

The purpose of this study was to analyze the sensitivity of meteorological fields and the variation of concentration of particulate matters (PMs) due to aerosol schemes and dust options within the WRF-Chem model to estimate Asian dusts affected on 29 May 2008 in the Korean peninsula. The anthropogenic emissions within the model were adopted by the $0.5^{\circ}{\pm}0.5^{\circ}$ RETRO of the global emissions, and the photolysis option was by Fast-J photolysis. Also, three scenarios such as the RADM2 chemical mechanism and MADE/SORGAM aerosol, the MOSAIC 8 section aerosol, and the GOCART dust erosion were simulated for calculating Asian dust emissions. As a result, the scenario of the RADM2 chemical mechanism & MADE/SORGAM aerosol depicted higher concentration than the others' in both Asian dusts and the background concentration of PMs. By comparing of the daily mean of PM10 measured at each air quality monitoring site in Seoul with the scenario results, the correlation coefficient was 0.67, and the root mean square error was $44{\mu}gm^{-3}$. In addition, the air temperature, the wind speed, the planetary boundary layer height, and the outgoing long-wave radiation were simulated under conditions of no chemical option with these three scenarios within the WRF or WRF-Chem model. Both the spatial distributions of the PBL height and the wind speed of u component among the meteorological factors were similar to those of the Asia dusts in range of 1,800-3,000 m and $2-16ms^{-1}$, respectively. And, it was shown that both scenarios of the RADM2 chemical mechanism and MADE/SORGAM aerosol and the GOCART dust erosion were interacted on-line between meteorological factors and Asian dusts or aerosols within the model because the outgoing long-wave radiation was changed to lower than the others.

• Korean Journal of Remote Sensing
• /
• v.27 no.2
• /
• pp.191-201
• /
• 2011

Soybean has widely grown for its edible bean which has numerous uses. Microwave remote sensing has a great potential over the conventional remote sensing with the visible and infrared spectra due to its all-weather day-and-night imaging capabilities. In this investigation, a ground-based polarimetric scatterometer operating at multiple frequencies was used to continuously monitor the crop conditions of a soybean field. Polarimetric backscatter data at L, C, and X-bands were acquired every 10 minutes on the microwave observations at various soybean stages. The polarimetric scatterometer consists of a vector network analyzer, a microwave switch, radio frequency cables, power unit and a personal computer. The polarimetric scatterometer components were installed inside an air-conditioned shelter to maintain constant temperature and humidity during the data acquisition period. The backscattering coefficients were calculated from the measured data at incidence angle $40^{\circ}$ and full polarization (HH, VV, HV, VH) by applying the radar equation. The soybean growth data such as leaf area index (LAI), plant height, fresh and dry weight, vegetation water content and pod weight were measured periodically throughout the growth season. We measured the temporal variations of backscattering coefficients of the soybean crop at L, C, and X-bands during a soybean growth period. In the three bands, VV-polarized backscattering coefficients were higher than HH-polarized backscattering coefficients until mid-June, and thereafter HH-polarized backscattering coefficients were higher than VV-, HV-polarized back scattering coefficients. However, the cross-over stage (HH > VV) was different for each frequency: DOY 200 for L-band and DOY 210 for both C and X-bands. The temporal trend of the backscattering coefficients for all bands agreed with the soybean growth data such as LAI, dry weight and plant height; i.e., increased until about DOY 271 and decreased afterward. We plotted the relationship between the backscattering coefficients with three bands and soybean growth parameters. The growth parameters were highly correlated with HH-polarization at L-band (over r=0.92).

• The Korean Journal of Nuclear Medicine
• /
• v.39 no.5
• /
• pp.278-283
• /
• 2005

Purpose: In prior study, we synthesized $^{99m}Tc$-galactosylated chitosan (GC) and performed in vivo biodistribution study, showed specific targeting to hepatocyte. The aim of this study is to evaluate the labeling efficiency and cytotoxicity of modified galactosylated chitosan compounds, galactosyl methylated chitosan (GMC) and HYNIC-galactosylated chitosan (GCH). Materials and Methods: GC, GMC and GCH were synthesized and radiolabeled with $^{99m}Tc$. Then, they were incubated for 6 hours at room temperature and human serum at $37^{\circ}C$. Labeling efficiencies were determined at 15, 30 m, 1, 2, 3 and 6 h after radiolabeling. To evaluate cytotoxicity, MTT assay was performed in HeLa and HepG2 cells. Results: In comparison with them of $^{99m}Tc$-GC labeling efficiencies of $^{99m}Tc$-GMC were significantly improved (100, 97 and 89%) in acetone and 96.3, 95.8 and 75.6% in saline at 15 m, 1 and 6 h, respectively). Moreover, $^{99m}Tc$-GCH showed more improved labeling efficiencies (>95% in acetone and human serum and >90% in saline at 6 h). In MTT assay, cytotoxicity was very low and not different from that of controls. Conclusion: These results represent that these compounds are radiochemically compatible radiopharmaceuticals, can be used in hepatocyte specific imaging study and in vivo gene or drug delivery monitoring.