http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Chung, Yong‐,Chan,Nguyen, Duy Khiem,Chun, Byoung Chul Wiley Subscription Services, Inc., A Wiley Company 2010 Polymer engineering and science Vol.50 No.12
<P><B>Abstract</B></P><P>Shape memory polyurethane (SMPU), flexibly crosslinked via a polyethyleneglycol (PEG) spacer attached to its side through an allophanate group, was tested for shape memory and compared with a linear SMPU. The new SMPU was composed of 4,4′‐methylenebis(phenylisocyanate) (MDI), poly(tetramethyleneglycol) (PTMG‐2000), and 1,4‐butanediol (BD), and included polyethyleneglycol (PEG‐200) as a spacer. A second MDI, linked to the carbamate group of the first MDI, served as the connecting point for the PEG‐200. Two types of SMPU, differing according to their soft segment (PTMG‐2000) and linker (PEG‐200) contents, were compared in mechanical and shape memory properties. In the best case, a 780% increase in maximum stress was attained without any sacrifice in strain for the new material compared with the linear polymer. In particular, the stress–strain curve showed that the PEG‐crosslinked SMPU had superior tensile mechanical properties. Its shape recovery was as high as 99%, which is the best value we have measured for an SMPU. After four cyclic tests, shape recovery remained greater than 95%. Shape retention of the best SMPU remained above 93% even after four cyclic tests. Here, results demonstrating the extraordinary shape memory properties of these types of SMPU, together with differential scanning calorimetry (DSC) and infrared spectroscopy data, are analyzed and discussed. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers</P>
The Significance of the Analytical Sciences In Environmental Assessment
Chung, Yong,Ahn, Hye-Won 한국분석과학회 1995 분석과학 Vol.8 No.4
The quality of human life is directly related to the quality of the environment. To assess environmental quality we must first determine the MCLG(Maximum Contaminant Level Goal), MCL(Maximum Contaminant Level), environmental impact and so on. The MCLG is the concentration at which no known adverse health effects occur. The MCLG is determined by risk assessment identifying which process is hazardous assessing, dose-response, human exposure, and characteristics of risk. With consideration of analytical methods, treatment technology, cost and regulatory impact, the MCL is set as close to the MCLG as possible. In this way, determination of the concentration and national distribution of contaminants is important for assessment of environmental quality The analytical sciences pose potential problems in assessing environmental quality. Continuing improvement in the performance of analytical instruments and operating technique has been lowering the limits of detectability. Contaminant concentration below the detection limit has usually been reported as ND(Not-Detected) and this has often been misunderstood as equivalent to zero. Because of this, more the contaminant concentration in the past was below the detection limit, whereas contaminants can be quantified now even though the contaminant concentration might remain the same or may even have decreased. In addition, environmental sampling has various components due to heterogeneous matrices. These samples are used to overestimate the concentration of the contaminant due to large variability, resulting in excess readings for MCL. In this paper, the significance of the analytical sciences is emphasized in both a conceptual and a technical approach to environmental assessment.
Environmental Studies of the Snail, Parafossarulus manchouricus, along Yeongsan River in Korea
Ahn, Yung-Kyum,Soh, Chin-Thack,Kim, Chong-Whan,Chung, Yong INSTITUTE OF TROPICAL MEDICINE YONSEI UNIVERSITY 1980 YONSEI REPORTS ON TROPICAL MEDICINE Vol.11 No.1
肝吸蟲의 蔓廷地域으로 알려진 榮山江流域을 中心으로 第一中間宿主인 왜우렁(Parafossarulus manchouricus)에 對하여 水質 및 環境條件에 따른 貝類의 生態 와 數種 河川汚染物質에 對한 影響을 調査하였다. 調査地域으로는 榮山江地域을 上, 中, 下流로 區分하고 上流는 潭陽郡 鳳山面 三支里 (U-1)와 長城郡 黃龍面 黃龍里 (U-2)를, 中流는 光山郡 東谷面 伏龍里 (M-1), 羅州郡 山浦面 花池里 (M-2) 및 羅州郡 榮山浦邑 富德里 (M-3)를, 下流는 羅州郡 多侍面 新風里 (D-1)와 ?平郡 ?平邑 鶴野里 (D-2)로 하였다. 調査時期는 1979年 年中 四季節로 區分하였고 單位面積內의 왜우렁을 採集比較하였다. 그 結果를 要約하면 다음과 같다. 1. 榮山江流域에서 왜우렁이 主로 棲息하는 支流 및 隣近水路의 地表土壤의 造成은 一般的으로 粘泥質이었다. 2. 왜우렁은 冬節(3℃)에 地表(28.6∼58.8%)에서도 採集할수 있었으나 많은수가 地表層 土壤의 1∼2cm內 (28.6∼58.8%)에서 越冬하고 있었다. 3. 水質의 理化學的 性狀 調査에서 pH, hardness, DO, Cl-, KMnO₄ consumption rate, NH₃-N, NO₂-N, NO₃-N, SO₄--, SO₃--, PO₄-³ 및 Hg 含量等은 地域的으로 若干의 汚染度를 나타낸 곳도 있으나 왜우렁 棲息에는 아무런 影響을 줄수 없는 範圍內였다. 4. 왜우렁의 肝吸蟲 幼蟲 感染貝는 冬節 0.8% (917개中 4개, 磨碎法)로 나타났으나 春夏秋節의 2,220개 에서는 檢出할수 없었다. 5. 水底地表層 土壤에서의 水銀檢出은 0.159∼0.575㎍/gm이었으나 물 (0.0002∼0.0024 ㎍/ml)과 왜우렁 (0.0379∼0.1385㎍/g/約5snails)의 含量은 低値를 보였다. 6. 왜우렁에 比較的 많이 感染된 吸蟲類 幼蟲 (蛙類寄生性 Loxogenes ilberum의 cercaria)은 Hg 20㎍/ml에서 50分, Cu 20㎍/ml에서 1時間20分內에 死滅하였다. 그러나 Pb, Zn, Cr, Cd 等에서는 50㎍/ml, 100㎍/ml에서도 6時間以上 生存을 나타내 直接的 短時間內의 影響은 없는 結果를 보여주고 있다. 以上 榮山江流域의 環境的 諸 與件은 왜우렁 棲息에 아직 阻害되는 影響은 미치지 못함을 알수 있다.