• 유기물자원화
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• 제15권1호
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• pp.134-142
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• 2007

본 연구는 생활쓰레기의 물리 화학적 분석 및 발열량 등으로 그 특성을 알고 반응기를 이용한 열중량감량 분석을 함으로써 열처리 시설의 가장 효율적인 운영에 기초자료가 됨을 목적으로 한다. 측정 결과는 다음과 같다. 쓰레기의 삼성분 중 가연분이 약 61%로 다른 수분(약 32%) 회분(약 7%)보다 함유량이 높았고 쓰레기의 원소분서결과 종류에 관계없이 탄소와 수고(약 94%)의 존재량이 대부분이었다. 쓰레기의 발열량 분석 결과 고위발열량은 2897.883(Kcal/kg)의 값을 갖는 것으로 나타났다. TGA를 이용하여 도시 생활쓰레기의 종류별 열적 특성을 분석한 결과 온도가 증가함에 따라서 시로 중에 함유된 휘발분이 지속적으로 무게 감량이 일어났으며 특히 $300{\sim}500^{\circ}C$에서 열중감량이 활발히 진행되고 그 반응속도에 차이가 있음을 알 수 있었다.

• 미생물학회지
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• 제24권3호
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• pp.308-316
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• 1986

Vertical distribution of heterotrophic bacteria and physico-chemical characteristics were measuted in Kum River estuarine sediments. And interrelationship between heterotrophic bacterka and environmental factors was also studied. The type of sediment of Site 1 was silty clay, and sand at Site 2. Annual pH ranges were between 7.1 and 7.7 in the clay type sediment (Site 1) and 6.9-7.2 in the sand type sediment (Site 2). It was shown that organic matter contents were higher in the clay type sediment than those of sand type sediment. Redox potential values of sediments were decreased rapidly with depth at Site 1, but those of Sete 2 showed vertical fluctuation. Nitrogens(ammonia+amino acid-N, nitrate-N, nitrite-N) and phosphate in the clay type sediment showed higher values than those of sand type sediment. Annual distribution of heterotrophic bacteria were ranged $6.71{\times}10^4$ cells/g dry wt. $-2.50{\times}10^6$ cells/g dry wt. In the clay type sediment and $2.67{\times}10^3$ cells/g dry wt. $-1.94{\times}10^6$ cells/g dry wt. in the sand type sediment. Distribution of proteolytic, lipolytic, and amylolytic bacteria were decreased with the depth and the highest density was found in April and the lowest in January. Bacterial populations in sediments were closely correlated with such environmental factors as pH, redox potential, moisture content, organic matter contents, and inorganic nutrients such as nitrite-N and phosphate-P.

• 한국식품위생안전성학회지
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• 제10권3호
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• pp.133-138
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• 1995

In vitro antimutagenic activity of methanol extract from brrwn rice and its physico-chemical characteristics were investigated using Salmonella typhimurium reversion assay and SOS chromotest. Methanol extracts of brown rice were not mutagenic compared with direct and indirect, mutagenicities of 4NQO (4-nitroquinoline oxide), 2NF(2-nitrofluorene), Trp-p-1(3-Amino-1,4-dimethyl-5H-pyrido-[4,3-b]indole), and Trp-p-2(3-Amino-1-methy-5H-pyrido-[4,3-b]indole). Antimutagenic activity against the indirect mutagenicties induced by Trp-p-1, Trp-p-2 and AFB1 (aflatoxin B1) was found in methanol extract. Even though antimutagenic activity showed dose-dependent, it remained constant at inhibition rate ranging 60~90% when the concentration was abov 3mg/plate in the S. typhimurium reversion assay and 0.2~0.6 mg/assay in the SOS chromotest. The antimutagenic activity of the methanol extracts was stable at various pH (2, 7 and 10), temperatures (60, 80 and 10$0^{\circ}C$)and heation times (2, 4, 6, 8, 10 min at 10$0^{\circ}C$).

• 한국식품영양학회지
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• 제22권1호
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• pp.92-96
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• 2009

Comparisons of the physico-chemical characteristics between white Atlantic potatoes and violet Bora Valley potatoes were performed. According to the results, Bora Valley had 7% higher moisture content than Atlantic, but there were no differences in crude fat and crude ash contents. Bora Valley, however, had about 3% less crude protein content than Atlantic. In a vitamin C analysis by HPLC, the Atlantic and Bora Valley potatoes contained 14% and 39% vitamin C, respectively, indicating that Bora Valley contained about twice as much of the vitamin as Atlantic. In a vitamin C analysis by HPLC, the Atlantic and Bora Valley potatoes contained 14% and 39% vitamin C, respectively, The dietary fiber content of Bora Valley was 3.12 g per 100 g higher than that of the Atlantic variety. While Atlantic contained neither glucose nor fructose, both sugars were measured in the Bora Valley potatoes, and there was no difference in sucrose content between the cultivar.

• 한국미생물·생명공학회지
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• 제18권1호
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• pp.35-38
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• 1990

정제된 저해물질의 Rf치는 0.12-0.71 사이였으며 melting point는 154.3-155.3$^{\circ}C$로 나타났다. 물, formic acid, ethylene glycol monomethyl ether에는 용해되지만 그외 대부분의 용매에서는 불용성이었고 흡습성이 매우 큰 물질이었다. Phenol-sulfuric acid, ninhydrin, silvernitrate-sodium hydroxide 반응은 양성이었으나, DNS 반응에서는 음성이며 자외선 조사하에서 형광을 나타내었다. 저해물질의 구성성분은 fructose와 aspartic acid로 확인되었으며 분자량이 약 1,050 정도였다.

• 한국토양비료학회지
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• 제21권3호
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• pp.241-245
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• 1988

야산지(野山地)를 경작지(耕作地)로 전환(轉換)하기 위한 기초자료(基礎資料)를 얻고자 영남지역(嶺南地域)을 중심(中心)으로 야산지(野山地) 토양(土壤)의 특성(特性)을 조사(調査)하였다. 일반적(一般的) 이화학성(理化學性)은 기경지(旣耕地) 토양(土壤)에 비해 불량(不良)하였다. 경사지(傾斜地)에서는 침식성인자(浸蝕性因子) K치(値)가 높고 입단안전성(粒團安定性)이 낮아 침식(浸蝕)에 의(依)한 표토(表土)의 유실(流失)이 있을 것으로 추정(推定)되었다. 주구성점토광물(主構成粘土鑛物)은 Kaoline계(系)이고 영일(迎日)II는 Bentonite로 판단(判斷)되었다. 이들지역(地域)의 토양(土壤)은 치환성(置換性) Al 및 Fe함량(含量)이 높고 인산흡착계수(燐酸吸着係數)가 246~551(Pmg/100g)으로 높았다. 따라서 야산지(野山地)를 경작지(耕作地)로 전환(轉換)하기 위해서는 물리(物理) 및 화학적(化學的) 성질(性質)의 개량(改良)이 선결(先決)되어야 하겠다.

• Journal of Ecology and Environment
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• 제29권4호
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• pp.389-398
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• 2006

To examine sediment characteristics and find anthropogenic effects on riverine wetland ecosystems, paleoecological study was carried out at Bam islands in Seoul. Three hundred cm deep sediment cores were retrieved and dated with the lamination analysis method until 36 cm depth (1986). Sediments were divided into three zones based on the depth profiles of physico-chemical variables: below 160 cm depth (before 1968), between 160 and 40cm depths and above 40cm depth (after 1986). Physico-chemical characteristics were very variable between 160 and 40cm depths and this indicates unstable sedimentation environment. Even though heavy metal concentrations were relatively low, Cd and As contents have increased continuously. Dry mass accumulation rates during $1968{\sim}1986\;and\;1987{\sim}2003$ were 140 and $21\;kg\;m^{-2}\;yr^{-1}$, respectively. This was related to flooding intensity and duration. Bulk density, water content, loss on ignition, N, C, C/N ratio were very similar to other river delta but Ca, Na and K contents were 2 to 4 times higher than others. Heavy metal contents except Pb were lower or similar to those in other studied marshes in Korea. Heavy metal and Mg contents were correlated with each other and this suggests that the source of heavy metals be parent rock. From $^{13}C$ dating dates of organic materials in sediment, it is suggested that organic matter originated from the watershed and flooding intensity in the watershed might be responsible for the source of sediments. This study provides reference data for the comparison of sediment characteristics at islands in river and for the management of Bam islands.

• Advances in environmental research
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• 제9권3호
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• pp.151-160
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• 2020

Water quality demonstrates physical, chemical and biological characteristics of water. The quality of surface and groundwater is currently an important concern with population growth and industrialization. Over exploitation of water resources due to demand is causing the deterioration of surface water and ground water. Periodic water quality testing must be carried out to protect our water resources. The present research analyses the spatial variation of surface water and groundwater in and around the lakes of Hyderabad. Twenty-Seven lakes and their neighboring bore water samples are obtained for water quality monitoring. Samples are evaluated for specific physico-chemical parameters such as pH, Total Dissolved Solids (TDS), Cl, SO₄, Na, K, Ca, Mg, and Total Hardness (TH). The spatial variation of water quality parameters for the 27 lakes and groundwater were analysed. Correlation and multiple regression analysis were carried out to determine comparative study of lake and ground water. The study found that most of the lakes were polluted and this had an impact on surrounding ground water.

• 한국대기환경학회지
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• 제26권2호
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• pp.118-136
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• 2010

Photochemical characteristics of ozone ($O_3$) and its precursors such as $O_3$ budget and $O_3-NO_x$-VOC sensitivity were analyzed in different physico-chemical properties of air masses around the Mexico City Metropolitan Area (MCMA) using aircraft observations during March 2006. The physico-chemical properties of air masses were categorized into 5 groups: boundary layer (BL), biomass burning (BB), free tropospheric continent (FTCO) and marine (FTMA), and Tula industrial complex (TIC). Results from the $O_3$ budget analysis indicated that $O_3$ production for BL, FTCO, and FTMA (for BB and TIC) was mainly controlled by a photochemical production pathway, a reaction of NO with $HO_2$ (with $RO_2$), while the main pathway of photochemical $O_3$ destruction for BL, FTCO, and FTMA (for BB and TIC) was a reaction of $HO_2$ with $O_3$ (of $H_2$ with $O^1$(D)). In addition, most of air mass categories (especially FTCO) were estimated to be $NO_x$-sensitive for $O_3$ production with lower $NO_y$, higher ratios of the other indicator species (e.g., $O_3/(NO_y-NO_x$), $H_2O_2/HNO_3$, etc.), and the lower removal rate of radicals ($\leq$0.5) by the reaction of OH with $NO_2$ than those of the VOC-sensitive condition.

• 한국식품조리과학회지
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• 제14권2호
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• pp.177-181
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• 1998

감자 및 닭튀김의 튀김회수에 따른 튀김유의 물리화학적 특성의 변화를 경시적으로 측정하였다. 튀김유의 온도변화는 닭튀김의 경우보다 감자튀김의 경우 더 큰 것으로 나타났다. 튀김과정 중에 튀김재료인 냉동감자의 중량감소는 21.9% 정도이었으며 닭튀김의 경우 닭튀김물의 중량감소는 12.8% 정도인 것으로 나타내었다. 튀김횟수인 15회까지의 감자 튀김유와 닭튀김유의 산가는 튀김횟수에 따라 지속적으로 증가하였으며 이들의 산가는 모두 0.6이하로 나타났다. 튀김횟수인 15회까지의 감자와 닭튀김유의 과산화물가는 일률적으로 증가하지 않았다. 튀김횟수에 따른 감자와 닭튀김유의 요오드가의 변화는 거의 보이지 않았다. 감자 및 닭튀김시 튀김유의 색상은 튀김횟수가 증가함에 따라 R(red)및 Y(yellow)가 뚜렷이 증가되었으며, 닭튀김유는 감자튀김유보다 훨씬 높았다. 튀김횟수가 증가함에 따라 linoleic acid의 감소와 oleic acid의 상대적인 증가를 나타내었다. Linoleic acid의 감소와 oleic acid의 증가는 감자튀김유보다는 닭튀김유에서 더욱 큰 것으로 나타났다.