• Korean Chemical Engineering Research
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• v.48 no.5
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• pp.609-614
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• 2010

In this study, emulsion polymerizations for synthesizing acrylic pressure-sensitive adhesive(PSA) were carried out using 2-ethylhexyl acrylate(2-EHA), n-butyl acrylate(n-BA), methyl metacrylate(MMA) as fundamental monomers and acrylic acid(AAc) as a functional monomer in the presence of anionic SLS (sodium lauryl sulfate). To obtain the optimized synthetic condition in the polymerization, we analyzed the polymerization variables such as the effect of surfactant concentration and hydrophilic lipophilic values(HLB). At the same time, the final adhesive properties were also analyzed by the function of the initiator concentration and buffer concentration. In the results, the most stable emulsion was obtained at the surfactant concentrations between 3 and 5 wt%. It was also determined the effect of HLB value of nonionic surfactant and the initiator concentrations on the gel content. Stable emulsion is obtained using the surfactant having HLB value of 12.3. The rate of emulsion polymerization was increased at the initiator concentration greater than 1 wt%, but the stability of the emulsion was decreased. Finally, the effect of the buffer concentrations on the pH and the conversion of the acrylic emulsion product were experimentally measured. At the sodium bicarbonate concentration above 0.4 wt%, the buffer infulence was apparent. The buffer effect was fully acceptable at the concentrations between 0.6 and 0.8 wt% regardless of the monomer composition.

• Korean journal of applied entomology
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• v.22 no.3 s.56
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• pp.186-192
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• 1983

The growth of germ tube of Fusarium oxysporum f. sp. cucumerinum was remarkably inhibited on the water agar treated with 100ppm of Fe-EDDHA, a synthetic iron chelating agent, whereas germination rate of microconidia did not show much differences compare with that of non treated water agar. Both of the germination and the germ tube elongation of microconidia were suppressed significantly in King's B agar by the bacterial siderophores produced by Pseudomonas putida. The highest germination of the chlamydospores was obtained in the soil added with $0.25\%$ of glucose plus $0.05\%$ of asparagine. The chlamydospores of cucumber wil fungus germinated about $14\%$ in rhizosphere soil of 2 day-old cucumber seedlings within 48 hours, and the germination was enhanced notably in rhizosphere soil of 10 day-old seedling. But the rates of germination was not increased according to cucumber growth age after 10 day-old seedling. The effect of P. putida and Fe-EDDHA on the germination on chlamydospores in conducive soil was not pronounced in the non-rhizosphere soil added with nutrient. However, the germination was suppressed significantly both in rhizosphere soil and in rhizosphere soil added with nutrient. The suppression of chlamydospore germination was greater in the bacteria inoculated soil than that in Fe-EDDHA treated soil.

• Korean Journal of Remote Sensing
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• v.29 no.1
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• pp.11-20
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• 2013

Space-borne Synthetic Aperture Radar(SAR) has been one of the most effective tools for monitoring quantitative oceanographic physical parameters. The Doppler information recorded in single-channel SAR raw data can be useful in estimating moving velocity of water mass in ocean. The Doppler shift is caused by the relative motion between SAR sensor and the water mass of ocean surface. Thus, the moving velocity can be extracted by measuring the Doppler anomaly between extracted Doppler centroid and predicted Doppler centroid. The predicted Doppler centroid, defined as the Doppler centroid assuming that the target is not moving, is calculated based on the geometric parameters of a satellite, such as the satellite's orbit, look angle, and attitude with regard to the rotating Earth. While the estimated Doppler shift, corresponding to the actual Doppler centroid in the situation of real SAR data acquisition, can be extracted directly from raw SAR signal data, which usually calculated by applying the Average Cross Correlation Coefficient(ACCC). The moving velocity was further refined to obtain ocean surface current by subtracting the phase velocity of Bragg-resonant capillary waves. These methods were applied to Envisat ASAR raw data acquired in the East Sea, and the extracted ocean surface currents were compared with the current measured by HF-radar.

• Journal of Food Hygiene and Safety
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• v.18 no.2
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• pp.61-66
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• 2003

This study was conducted to produce the egg yolk Imunoglobulin (IgY) on Vibrio parahaemolyticus from immunized hen with lipopolysaccharide (LPS). Vibrio parahaemolyticus is considered as a potentially pathogenic bacteria, the causative agents of the gastroenteritis. According as the LPS antigens were injected into laying hens in order to produce antibodies against Vibrio parahaemolyticus in egg yolk. After chickens were immunized four times in 2 weeks interval and three times booster in 2 weeks interval, the profile of antibody Production was examined by ELISA. The Production of antibody in egg yolk was started in 1 week after the first immunization, reached peak in 7 weeks and maintained until 13 weeks later. The antibody titre in serum showed similar tendency as IgY. No significant difference in antibody titre when the titre compared to water diluted IgY and commercial IgY kit. Purified IgY reacted with only Vibrio parahaemolyticus, but other Vibrio species and food-borne pathogenic bacteria. In conclusion, we showed that it is possible to obtain a high antibody titre in chicken with quite low amounts of LPS antigen. These results suggested that egg yolk antibodies could be a good source for production of specific antibodies to pathogenic bacteria inducing epidemic gastroenteritis.

• Journal of Food Hygiene and Safety
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• v.22 no.4
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• pp.288-293
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• 2007

To evaluate effects of airborne microorganisms in fresh cut processing plant, microorganisms in air, equipments, raw material, water and final product were isolated and identified using Vitek (R)2 compact system. Airborne microorganisms were isolated from 1000L air using air sampler for floating microorganisms and plate count agar for falling microorganisms. And contaminated microorganisms of equipment, water, and product were isolated from plate count agar plate. Total plate counts for floating and falling, raw material, equipments and final product were $10^2-10^3CFU/m^3,{\sim}10^1CFU/plate,\;10^3CFU/g,{\sim}10^4CFU/cm^2\;and\;10^4CFU/g$, respectively. From the result of isolated microorganism identification from raw material to final product, airborne microorganisms could affect the flora of final product.

• Korean journal of applied entomology
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• v.31 no.3
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• pp.205-240
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• 1992

In reality, it is a green revolution of the entire agricultural matrix in Korea that integrated pest control plays an important role in the possible breakthrough in rice self-sufficiency. In paddy agroecosystem as man-modified environment, rice is newly established every year by transplantation under diverse water regimes which affect a microclimate. Standing water benefits rice by regulating the microclimate, but it favors the multiplication of certain pets through the amelioration of the microclimate. Further, the introduction of high yielding varieties with the changing of cultural practices results in changing occurrence pattern of certain pests. In general, japonica type varieties lack genes resistant to most of the important pests and insect-borne virus diseases, whereas indica type possesses more genes conferring varietal resistance. Thus, this differences among indica type, form the background of different approaches to pest management. The changes in rice cultivation such as double cropping, growing high-yielding varieties requiring heavy fertilization, earlier transplanting, intensvie-spacing transplanting, and intensive pesticide use as a consequence of the adoption of improves rice production technology, have intensified the pest problems rather than reduced them. The cultivation of resistant varieties are highly effective to the pest, their long term stability is threathened because of the development of new biotypes which can detroy these varieties. So far, three biotypes of N. lugens are reported in Korea. Since each resistant variety is expected to maintain several years the sequential release of another new variety with a different gene at intervals is practised as a gene rotation program. Another approach, breeding multilines that have more than two genes for resistance in a variety are successfully demonstrated. The average annual rice losses during the last 15 years of 1977-’91 are 9.3% due to insect pests without chemical control undertaken, wehreas there is a average 2.4% despite farmers’insecticide application at the same period. In other words, the average annual losses are prvented by 6.9% when chemical control is properly employed. However, the continuous use of a same group of insecticides is followed by the development of pest resistance. Resistant development of C. suppressalis, L. striatellus and N. cincticeps is observed to organophosphorous insecticides by the mid-1960s, and to carbamates by the early 1970s in various parts of the country. Thus, it is apparent that a scheduled chemical control for rice production systems becomes uneconomical and that a reduction in energy input without impairing the rice yield, is necessarily improved through the implementation of integrated pest management systems. Nationwide pest forecasting system conducted by the government organization is a unique network of investigation for purpose of making pest control timely in terms of economic thresholds. A wise plant protection is expected to establish pest management systems in appropriate integration of resistant varieties, biological agents, cultural practices and other measures in harmony with minimizing use of chemical applications as a last weapon relying on economic thresholds.

• Journal of Food Hygiene and Safety
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• v.31 no.4
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• pp.264-271
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• 2016

The purpose of this study was to investigate contamination sources of baby leafy vegetables by assessing microbial loads on baby leafy vegetables and agricultural inputs contacted with the vegetables. To estimate microbial loads, fecal indicators (coliform and Escherichia coli) and foodborne pathogens (E. coli O157:H7, Salmonella spp., Staphylococcus aureus, Listeria monocytogenes, and Bacillus cereus) were examined. A total of 126 samples including eleven kinds of leafy vegetables, irrigation water, media, and tools were tested, resulting in coliform contamination observed from most of samples. For E. coli, 10.3% (13/126) of the samples were positive including irrigation water, knife, handler, media, tools, and three kinds of leafy vegetables. B. cereus was detected from 38% (48/126) of the samples including media, tools and three kinds of leafy vegetables. No E. coli O157:H7, Salmonella spp., and L. monocytogenes was detected. This result implies that contacting with agricultural inputs could explain microbial load of baby leafy vegetables.

• Korean Journal of Remote Sensing
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• v.40 no.2
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• pp.203-217
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• 2024

The Land Use, Land-Use Change and Forestry (LULUCF) sector of the National Greenhouse Gas Inventory is crucial for obtaining data on carbon sinks, necessitating accurate estimations. This study analyzes cases of countries applying the LULUCF sector at the Tier 3 level to propose enhanced methodologies for carbon sink estimation. In nations like Japan and Western Europe, satellite spatial information such as SPOT, Landsat, and Light Detection and Ranging (LiDAR)is used alongside national statistical data to estimate LULUCF. However, in Korea, the lack of land use change data and the absence of integrated management by category, measurement is predominantly conducted at the Tier 1 level, except for certain forest areas. In this study, Space-borne LiDAR Global Ecosystem Dynamics Investigation (GEDI) was used to calculate forest canopy heights based on Relative Height 100 (RH100) in the cities of Icheon, Gwangju, and Yeoju in Gyeonggi Province, Korea. These canopy heights were compared with the 1:5,000 scale forest maps used for the National Inventory Report in Korea. The GEDI data showed a maximum canopy height of 29.44 meters (m) in Gwangju, contrasting with the forest type maps that reported heights up to 34 m in Gwangju and parts of Icheon, and a minimum of 2 m in Icheon. Additionally, this study utilized Ordinary Least Squares(OLS)regression analysis to compare GEDI RH100 data with forest stand heights at the eup-myeon-dong level using ArcGIS, revealing Standard Deviations (SDs)ranging from -1.4 to 2.5, indicating significant regional variability. Areas where forest stand heights were higher than GEDI measurements showed greater variability, whereas locations with lower tree heights from forest type maps demonstrated lower SDs. The discrepancies between GEDI and actual measurements suggest the potential for improving height estimations through the application of high-resolution remote sensing techniques. To enhance future assessments of forest biomass and carbon storage at the Tier 3 level, high-resolution, reliable data are essential. These findings underscore the urgent need for integrating high-resolution, spatially explicit LiDAR data to enhance the accuracy of carbon sink calculations in Korea.

• Journal of Dairy Science and Biotechnology
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• v.33 no.1
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• pp.1-15
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• 2015

Before the advent of pasteurization and other microbiological controls in the dairy industry, milk product-borne diseases such as scarlet fever, typhoid fever, septic sore throat, and tuberculosis were globally widespread. Pasteurization was invented by Louis Pasteur, and it has been considered as one of the most effective ways to control milk product-borne diseases since the 20th century. Nevertheless, till date, various types of cheese in the EU, the USA, and other countries are made from unpasteurized milk as artisan cheese, following the specific food regulations of each nation. Furthermore, after the effectiveness of the Free Trade Agreement (FTA) negotiations between Korea and many nations, the import of various types of cheese made in different conditions and influenced by acidity, preservatives, temperature, competing flora, water activity, and salt concentration increased yearly. Hence, the objective of this review was to describe (1) the 60-day aging rule of cheese, (2) characteristics of the outbreaks linked to cheese manufactured from unpasteurized milk since 1998 to 2011 in USA, and (3) serious health risks from unpasteurized milk, to ensure food protection and safety and to use this basic information for risk assessment.

• Journal of Preventive Medicine and Public Health
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• v.13 no.1
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• pp.3-12
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• 1980

Certain heavy metals which may lead peoples to poisonous status are widely used in industry and their uses have been increasing along with rapid industrialization of this country. Such an increasement of metal uses aggravates the status of environmental pollution affecting foodstuffs which are the most important life supporting factor of animal and humanbeing. Concerning the safety measures to minimize food-borne transmission of such hazardous metals, surveillance is the backbone of them and probably more so with a potential problem such as intoxication. Theoretically, this surveillance should include the determination of levels of heavy metal toxicants in foods, the determination of food consumption patterns and typical total diet, and the estimation of total load of the metal contaminant from all sources of exposure including air, water, and occupational sources. In recent year, actually, such estimates on the total daily intake of some heavy metals from foods have been made in several developed countries and a wide variation of date by season, locality, and research method was recognized. Also in this country, this kind of research data is vitally needed to make up for the serious shortage or lack of references to estimate the total amount of heavy metal intake of the people. In this study, a modification model for estimation of the total daily intake of cadmium copper, nickel, zinc, and lead through foods was applied and concentrations of the above metals in crops cultivated in this country were measured with atomic absorption spectro photometer to get the following results. 1. Level of heavy metal concentration in crops Generally, the levels of such metals in essential crops such as rice, cucumber, radish. chinese cabbage, apple, pear, grape, and orange are similar or lower than those in Japan and other developed countries. By the way, a striking result on cadmium concentration was increasement of its concentration in rice from $0{\sim}0.035ppm$ in 1970 to 0.11ppm in this study. However, the value is still far below the. Japanese Permissible Lebel of 1.0ppm. 2. Estimation of total daily intake per capita from foods A new model for estimation was devised utilizing levels of metal concentration in foods, amount of food consumed, and other food factors. Based on the above method, the daily intake of cadmium was estimated to be $70.53{\mu}g/man/day$ in average which was as high as the Limit Value of ILO/WHO(up to $71.4{\mu}g/man/day$). Also, 3.89mg of Zinc, 1.65mg of cuppor, 0.32mg of lead were given as the total daily intake per capita by this research. 3. Efficacy of washing or skinning to decrease the amount of metals in crops After washing the crops sufficiently with commercial linear alkylate sulfonate, the concentration of heavy metals could be reduced to $50{\sim}80%$ showing decreasement rate of $20{\sim}50%$. Also, after skinning the fruits, decreasement rate of the heavy metal concentration shelved $0{\sim}50%$.