This study examined the effects of freshwater discharge by artificial dikes from the Kanwol and Bunam lakes on the dynamics in the Chunsu Bay, Yellow Sea, Korea, during the summer season based on three-dimensional numerical modeling experiments. Model performances were evaluated in terms of skill scores for tidal elevation, velocity, temperature, and salinity and these scores mostly exceeded 90 %. The variability in residual currents before and after the freshwater discharge was examined. The large amount of lake water discharge through artificial dikes may result in a dramatically changed density field in the Chunsu Bay, leading to an estuarine circulation system. The density-driven current formed as a result of the freshwater inflow through the artificial dikes (Kanwol/Bunam) caused a partial change in the tidal circulation and a change in the scale and location of paired residual eddies. The stratification formed by strengthened static stability following the freshwater discharge led to a dramatic increase in the Richardson number and lasted for a few weeks. The strong stratification suppressed the vertical flux and inhibited surface aerated water mixing with bottom water. This phenomenon would have direct and indirect impacts on the marine environment such as hypoxia/anoxia formation at the bottom.

본 연구는 학부모를 대상으로 식품첨가물 및 보존료에 대한 인식 수준과 정보요구도를 파악하고 이를 바탕으로 학부모의 식품첨가물 및 보존료에 대한 올바른 이해와 안전한 식생활을 위한 교육자료를 개발하고자 하였다. 2014년 서울 경기지역 초등학생을 둔 학부모 381명을 대상으로 식품첨가물 및 보존료에 대한 인식 및 정보요구도에 대한 설문조사를 수행한 결과 응답자 중 가공식품 구입시 안전성을 가장 중요한 요소라고 응답하였으며, 41.5%가 식품 첨가물을 가장 식품안전을 위협하는 것이라고 응답하였으며, 식품 첨가물 중에서는 보존료가 가장 위험하다고 응답하였다. 그러나 응답자의 90.6%가 식품첨가물 및 보존료에 대한 교육 경험이 없다고 응답하였다. 설문결과와 학부모들의 정보요구도에 따라 교육홍보책자인 ‘보존료 바르게 알기’를 개발하였다. ‘보존료 바르게 알기’는 ‘보존료란 어떤 물질인가요?’, ‘보존료는 어떤 종류가 있나요?’, ‘보존료는 안전한가요?’, ‘가공식품, 어떻게 섭취해야 하나요?’, ‘식품첨가물은 식약처가 철저히 관리하고 있어요’ 등의 5장으로 구성하여 소비자인 학부모들이 알고싶어하는 내용들을 알기 쉽고 재미있게 전달할 수 있도록 구성하였다. 개발된 교육홍보책자를 초등학교 학부모에게 시범 적용한 결과, 사전 18.9%만이 보존료가 무엇인지 알고 있다고 응답한 수준에서 사후 90.9%가 그 역할을 이해하고 72.7%가 안전하다고 응답하여 개발된 책자가 보존료에 대한 이해도를 크게 높이고 보존료에 대한 오해를 바로잡을 수 있는 것을 확인할 수 있었다. 따라서 본 연구에서 개발된 교육홍보책자는 학부모를 비롯한 일반소비자들에게 보존료에 대한 이해를 높일 수 있는 효과적인 정보전달매체로 활용될 수 있을 것이다.

The composition of the deicer sprayed on the highway is spreading over the highway by the scattering or snow removal activity, or car movement and consequently affecting the vegetation environment around the highway. These are the cause of the damage of fruit trees and crops, and also the cause of corrosion of highway structures. The goal of this study is to estimate the detected range of deicer components from a highway. The concentration of the deicer components in gauze and soil were investigated according to the crossing distance from the highway. The data collected were then used to estimate the concentration range of deicer components in a rage of distance up to 100 m from the highway where the deicer was spread. The sample time and weight of gauze were measured before and after installation, and the soil was collected at more than three points in parallel with the highway at the gauze installation point. The components in gauze and soil were investigated in addition to the deicer components (Ca2+, Na+, Cl-) as well as Mg2+ and K+. As Ca2+ and Cl- components of deicer were affected by agricultural use, Na+ component was selected as a tracer and further SAR (Sodium Adsorption Ratio) of soil was analyzed to examine the degree of influence on vegetation indirectly. The gauze concentration was evaluated by the concentration of the deicer ingredient at the background concentration of the blank gauze. The total amount of the deicer sprayed in the study road for 4 months (winter season) was about 93 ton/km. In the gauze test, the spread of the deicer was detected at a distance of 100 m in study area, but the concentration of the deicer in the gauze by distance decreased rapidly within 10 m from the highway. And concentration of the deicer components in gauze and soil came down after rainy season (August ~ Sep.). The results showed that the components of the deicer could be spread widely by the wind. The effective range of the deicer on vegetation based on SAR in soil was estimated to be less than 20 m from the highway. This study examines the concentration changes of the deicer components in gauze and soils and shows that deicer components sprayed on the highway are accumulated and moved over time by wind, snow removal, terrain, water system and land use around the highway.

The citrus leaf miner (CLM) is an important citrus pest. A thorough understanding of the biology and population dynamics of CLM are essential for development of reliable pest population prediction system. We investigated the developmental periods of the species under ten constant temperature schemes (12.5℃~39℃). Furthermore, we established a development model of CLM, based on the result of a laboratory experiment. The immature developmental duration of CLM at constant temperatures were 63.5 days at 15℃, 23.9 days at 21℃, 15.6 days at 27℃, and 12.3 days at 33℃, showing statistically significant difference among temperature regimes. The lower threshold temperature and thermal constant were 11.3℃ and 243.7 DD, respectively, for immature development. In relation to temperature, non-linear development models were established for each developmental stage of CLM.

The citrus leaf miner (CLM) is a of important citrus pests in Jeju island, but it’s not clear about ecology of over-wintering in Jeju. We investigated the developmental stage to know how the CLM overwinters in 20 sites. And we investigated the mortality of larvae, pupae and adult stage of CLM in open citrus cultivated field December, 2017 to April 2018 and growth chamber conditions(from –10 to 5 ℃). As a result, no larvae and adult survived open field during winter. We concluded that the CLM usually overwinters as pupa during winter.

건강기능식품에서 이산화규소 분석 방법을 확립하기 위하여 산(불산과 붕산)분해를 이용한 ICP-OES 방법을 수행하였다. 이 방법의 검출한계와 정량한계는 각각 0.07 mg/ L, 0.20 mg/L 이었다. 검량선은 0.2~20.0 mg/L의 농도범위 에서 우수한 직선성(r2 0.99)을 보였다. 글루코사민 제품에 이산화규소 0.4, 1.0, 2.0% (w/w)를 첨가하여 시험한 결과 90.22~94.14%의 회수율과 0.72~1.67%의 정밀성을 나타내었다. 확립된 방법으로 시중에 유통되는 건강기능식품 11 품목의 이산화규소 함량을 분석한 결과 0.02~1.80% (w/w) 로 나타났다. 이 결과는 건강기능식품에 이산화규소의 사 용기준 2% (w/w) 이하를 만족하는 결과로 시험한 제품들 은 규격에 적합하였다. 따라서 본 연구에서 확립된 이 방법은 건강기능식품 중 이산화규소를 쉽고, 빠르게 분석할 수 있으며, 건강기능식품 중 이산화규소 함량 분석에 효율 적으로 사용될 수 있다

A sintered body of TiB2-reinforced iron matrix composite (Fe-TiB2) is fabricated by pressureless-sintering of a mixture of titanium hydride (TiH2) and iron boride (FeB) powders. The powder mixture is prepared in a planetary ball-mill at 700 rpm for 3 h and then pressurelessly sintered at 1300, 1350 and 1400oC for 0-2 h. The optimal sintering temperature for high densities (above 95% relative density) is between 1350 and 1400oC, where the holding time can be varied from 0.25 to 2 h. A maximum relative density of 96.0% is obtained from the (FeB+TiH2) powder compacts sintered at 1400oC for 2 h. Sintered compacts have two main phases of Fe and TiB2 along with traces of TiB, which seems to be formed through the reaction of TiB2 formed at lower temperatures during the heating stage with the excess Ti that is intentionally added to complete the reaction for TiB2 formation. Nearly fully densified sintered compacts show a homogeneous microstructure composed of fine TiB2 particulates with submicron sizes and an Fe-matrix. A maximum hardness of 71.2 HRC is obtained from the specimen sintered at 1400oC for 0.5 h, which is nearly equivalent to the HRC of conventional WC-Co hardmetals containing 20 wt% Co.

This study was performed to evaluate antimicrobial resistance of food-borne pathogens isolated from retail meat in Korea. A total of 157 samples of beef, pork, and chicken were collected and analyzed for E. coli, Salmonella, Campylobacter. Resistances to tetracycline were declined in accord with reduced usage of tetracycline in live stock production. E. coli stains from chicken meat had higher multi-drug resistance ratio than strains from other meat. One extended spectrum beta lactamase (ESBL) producing E. coli and two ESBL producing Salmonella were identified in this study. ESBL producing Salmonella strains were confirmed to carry CTX-M-1 type genes.