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브레이크 디스크 열전달 해석을 통한 알파인 테스트 검토
박용우(Yongwoo Park),이광호(Gwangho Lee) 한국자동차공학회 2007 한국자동차공학회 Symposium Vol.- No.-
A general-purpose CFD package was used to simulate the air flow around the front brake. In order to build the computational model there were some assumptions. All components influencing the air flow to the brake disk were simplified. The steady state was assumed so as not to consider the unsteady interaction between the rotor and the stationary parts such as caliper, knuckle in the study. To evaluate the brake cooling performance the average heat transfer coefficient on the brake rotor surfaces was calculated, and the heat transfer analysis of the disc was performed. The peak temperature of the disc in the Alpine test was predicted via the heat transfer analysis. The Alpine test is the mountain descent braking test mode. The dust cover was modified to improve the cooling performance. The simulation of the modified front brake system was also performed.
우유 중 아플라톡신 M<sub>1</sub> 오염도 조사연구
박성국(Sung Kug Park),강영운(YoungWoon Kang),권기성(Kisung Kwon),이광호(GwangHo Lee),김미혜(Meehye Kim) 한국식품과학회 2012 한국식품과학회지 Vol.44 No.2
본 연구에서 적용한 시험법의 회수율은 97.4-122.5%, 상대표준 편차(RSD)는 6%이내로서 적합한 시험법임을 확인하였다. 조사된 원유 및 시유의 검출농도는 아플라톡신 M<SUB>1</SUB>이 평균 29.6 ng/kg(5.4-72.7 ng/kg)로 나타났으며, 원유 및 시유에 대한 아플라톡신 M<SUB>1</SUB> 오염수준은 현행 식품공전에서 정한 허용기준치인 500 ng/kg 보다 낮은 안전한 수준인 것으로 판단된다. Raw milk samples (n=28) obtained from milk tanks in 3 dairy plants of different regions and commercial milks (n=100) were collected from six cities. These samples were analyzed for the level of aflatoxin M<sub>1</sub> contamination using immunoaffinity columns and high performance liquid chromatography coupled with fluorescent detectors. Confirmation of aflatoxin M<sub>1</sub> (AFM<sub>1</sub>) identified in positive samples was based on the formation of the hemiacetal derivative (AFM<sub>2</sub>a) after derivatization with trifluroacetic acid. The average concentrations of aflatoxin M<sub>1</sub> in the raw milks were 25.1 ng/kg, and those values in commercial milks were 29.8 ng/kg. The highest level of aflatoxin M<sub>1</sub> in milk was 72.7 ng/kg. These results showed that the contamination of aflatoxin M<sub>1</sub> in milks consumed in the Korea was quite low compared to the standard in Korea Food Code (aflatoxin M<sub>1</sub> 500 ng/kg).
축산식품 중 아미노글리코사이드계 항생제 잔류량 분석 및 실태조사
강영운(YoungWoon Kang),주현진(HyunJin Joo),김양선(YangSun Kim),조유진(YuJin Cho),김희연(HeeYun Kim),이광호(GwangHo Lee),김미혜(Meehye Kim) 한국식품과학회 2011 한국식품과학회지 Vol.43 No.1
본 연구에서 개발된 시험법은 고감도를 가지고 선택성이 뛰어난 LC/MS/MS를 이용함으로서 한번의 시료 전처리와 동시 분석을 통하여 아미노글리코사이드계 항생제 5종의 잔류량 분석을 가능케 하였다(15,16). 개발된 시험법은 CODEX의 가이드라인에 따라 검량선의 직선성, 회수율, 정성한계 및 정량한계, 정확성 및 정밀성 등을 고찰하여 시험법의 실효성을 검증하였다. 확립된 시험법을 이용하여 돼지고기, 닭고기, 쇠고기 등 총 250건을 분석한 결과 5건이 검출되었으며 검출율은 2%로서 검출된 양은 모두 각각의 잔류허용기준보다 낮은 수준이었으나 한 시료에서 겐타마이신과 디하이드로스트렙토마이신이 동시 검출되었다. 이 결과는 여러 종류의 항생제들을 동시에 처방하고 있다는 사실을 입증하고 있다. 그러나, 기기분석을 이용하여 아미노글리 코사이드계 항생제의 잔류량 실태조사 결과 검출율 및 검출량이 낮은 안전한 수준이었다. It is possible that veterinary medicines remain in livestock food products, according to the use of many and various veterinary medicines to protect against disease when livestock animals are breed in limited space. Concentrated and continuous monitoring of residues is needed due to increases in resistance to antibiotics and side effects by eating livestock food products. We developed an analysis method for detecting streptomycin, dihydrostreptomycin, neomycin, gentamicin and spectinomycin in meat using LC/MS/MS and measured sensitivity, precision, accuracy, linearity and recovery according to CODEX guidelines to acquire confidence in the analysis method. Based on the results, we acquired good sensitivity compared to the maximum residue limit (MRL) as limits of detection (LOD) were 0.002-0.016 ㎎/㎏ and limits of quantification (LOQ) were 0.006-0.050 ㎎/㎏. The analysis method satisfied the CODEX guidelines. The linearity (r²) values of aminoglycoside antibiotics were 0.9936-0.9980, recoveries were 60-110% and relative standard deviations (RSD) were within 15%. As a result of monitoring for residues in a total 250 samples of livestock foods such as pork, chicken, and beef by the confirmed method, dihydrostreptomycin and gentamicin were detected in 5 pork samples. The residues of these antibiotics were within the MRLs. Thus, the detection ratio was 2% as 5 samples were identified from 250 samples.