• Journal of Nutrition and Health
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• 제35권9호
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• pp.926-931
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• 2002

The antimicrobial properties of extracts of Prunus mume were tested on Salmonella paratyphimurium and S. typhimurium. First, the Prumus mume was extracted with methanol at several temperatures, and then fractionation of the methanol extracts from Prunus mume was carried out by using petroleum ether, chloroform, ethyl acetate or butanol. Secondly, absorption column chromatoraphy (using a Diaion HP 20) was conducted to eliminate some water soluble materials that might inhibit the antimicrobial activity of some extracts. The antimicrobial activitry of each of the Prunus mume extracts was determined using a paper disc method against several food-borne pathogens, The growth inhibition curve was determine using butanol extracts of Prunus mume against Salmonella typhimurium. The extraction temperature did not have any significant effect on the yield of the extract or on the level of antimicrobial activity. The butanol extract of Prunus mume showed strong antimicrobial activity against Salmonella paratyphimurium and S. typhimurium; a 1,000 ppm of butanol extract of Prunus mume retared the growth of S. typhimurium up to 36 hours. (Korean J Nutrition 35(9) : 926~931, 2002)

• Preventive Nutrition and Food Science
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• 제17권3호
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• pp.228-233
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• 2012

Trifoliate orange seed extracts (TSEs) were prepared from different solvents, water (TW), ethanol (TE), and n-hexane (TH), and assessed for their antimicrobial activities against six gram-negative food-borne pathogens (Escherichia coli KCTC 1039, Escherichia coli O157:H7 ATCC 43895, Salmonella Enteritidis ATCC 3311, Salmonella Typhimurium KCCM 11862, Shigella sonnei KCTC 2518, and Vibrio parahaemolyticus ATCC 17802). Among the tested TSEs, TE and TH showed a slight inhibition activity on V. parahaemolyticus ATCC 17802, but a good growth inhibition activity on Sal. Typhimurium KCCM 11862. TH and TE showed steady growth inhibition activity with increasing growth time after 6 hr when compared to the control (p<0.05). From these results, we confirmed the possibility of TH and TE as antimicrobial materials.

• Food Science and Biotechnology
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• 제15권2호
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• pp.260-263
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• 2006

In this study, we investigated the antimicrobial effect of 14 different herbal petal extracts on various foodborne and food spoilage bacteria. Herbal petal extracts were prepared with 70% ethanol followed by sequential hexane, chloroform, ethyl acetate, n-butanol, and water fractionation. Antimicrobial activity was highest in the ethanol fraction from roselle (Hibiscus sabdariffa L.) petals as determined by the paper disc method. The roselle ethanol extract retarded the growth of food spoilage bacteria in kimbap (rice rolled in dried laver). Foodborne microorganisms (e.g. Bacillus cereus and Clostridium perfringens), on the other hand, were most efficiently inhibited by the ethyl acetate fraction of the roselle petal extract as determined by growth inhibition curves. Our study shows that roselle petals harbor antimicrobial activity against foodborne and food spoilage microorganisms. The critical ingredient is highly enriched in the ethyl acetate fraction of the extract.

• Journal of Preventive Medicine and Public Health
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• 제7권2호
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• pp.327-332
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• 1974

대구시(大邱市) 주변 군(軍)주둔지역에서 의뢰된 298건(件)의 우물을 대상으로 이화학적(理化學的) 및 세균학적(細菌學的) 수질구조(水質構造)를 1974년(年) 1월(月)부터 11월(月) 말(末) 까지 실시하여 얻은 성적을 요약하면 다음과 같다. 1. 우물의 물리학적소견(物理學的所見)으로, 탁도(濁度), 색도(色度) 및 취기(臭氣)는 거의 전례(全例)에서 정상(正常)범위내(內)에 있었다. 2. 화학적구조(化學的構造)에서 pH, $KMnO_4$ 소비량, 총경도, 염소는 대체(大體)로 정상(正常)범위내(內)에 있었다. 3. 유기물질(有機物質)의 분해과정을 나타내는 유리(游離)ammonia가 33.2%, nitrite가 45.5%에서 양성(陽性)을 나타내었다. 4. 세균학적검사(細菌學的檢査)에서는 대장균군검사(大腸菌群檢査)에서 40.3% 양성(陽性)이었다. 5. nitrite와 대장균구사(大腸菌構査)의 비교에서는 대장균군(大腸菌群)이 양성(陽性)으로 나타난 것 중(中)에서 60.1%서서 nitrite 수질검사(水質檢査) 기준(基準)을 초과하였고 nitrite가 양성(陽性)으로 나타난 것 중(中)에서는 대장균군(大腸菌群)이 모두 기준(基準)이상이었다. 6. 오염은 전반적으로 봄과 여름에 현저했으며 가을과 겨울에는 급격히 감소되었다.

• 동력기계공학회지
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• 제13권1호
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• pp.39-45
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• 2009

The attenuation of the fundamental non-torsional modes that propagate down buried steel water pipes has been studied. The mode shapes, mode attenuation due to leakage into the surrounding medium and the scattering of the modes as they interact with pipe joints and fittings have been investigated. In the low frequency region the mode predicted to dominate over significant propagation distances approximates a plane wave in the water within pipe. The established acoustic technique used to locate leaks in buried steel water pipes assumes that leak noise propagates as a single non-dispersive mode at a velocity related to the low frequency asymptote of this water borne mode.

• 동력기계공학회지
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• 제17권1호
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• pp.36-41
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• 2013

A study of the possible axisymmetric modes that propagate at low frequencies in buried, water-filled pipes is presented. It is well known that for a vacuum-pipe-vacuum system the sole non-torsional axisymmetric mode that exists at low frequencies is the fundamental L(0,1) mode. When a pipe is filled with water and still surrounded by a vacuum it is also known that another mode then appears which at low frequencies is characterized by predominantly axial water-borne displacements. In addition to these modes. this paper explores two other, less well known axisymmetric modes whose exitence depends on the acoustic properties of the outer medium that surrounds a pipe. The predicted characteristics of these modes are presented and the likelihood of them propagating over any significant distance in a buried water pipe is discussed.

• 한국물환경학회지
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• 제27권1호
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• pp.1-8
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• 2011

네팔의 천연 수자원은 풍부한 편이나 모든 인구가 안전하고 깨끗한 식수를 공급받고 있지는 못한 상황이다. 또한, 폐수 처리에 대한 상황 역시 매우 열악한 상태라고 할 수 있다. 최근, 도시로의 인구 유입이 증가함에 따라 안전한 물의 공급 및 공중 위생에 대한 관심이 증대되고 있으나, 수인성 질환의 발병률은 여전히 높은 상황이다. 본 논문에서는 네팔의 수질 오염, 식수에서의 비소 오염, 폐수 처리, 그리고 대중의 건강에 대한 수질 오염의 영향 등에 대해 검토하였다. 또한, 폐수 처리와 연관된 규제와 관련하여 한국의 상황과 비교하여 양국의 상황을 비교 고찰하였다. 이러한 내용들에 의거하여 대중의 건강 증진을 위한 현존 문제점들의 해결 방안들을 제시하였다.

• Advances in nano research
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• 제5권2호
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• pp.127-140
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• 2017

Metal nanoparticles have been intensively studied within the past decade. Nano-sized materials have been an important subject in basic and applied sciences. Zinc oxide nanoparticles have received considerable attention due to their unique antibacterial, antifungal, and UV filtering properties, high catalytic and photochemical activity. In this study, microbiological aspects of scale formation in PVC pipelines bacteria and fungi were isolated. In the emerging issue of increased multi-resistant properties in water borne pathogens, zinc oxide (ZnO) nanoparticle are being used increasingly as antimicrobial agents. Thus, the minimum bactericidal concentration (MBC) and minimum fungal concentration of ZnO nanoparticles towards pathogens microbe were examined in this study. The results obtained suggested that ZnO nanoparticles exhibit a good anti fungal activity than bactericidal effect towards all pathogens tested in in-vitro disc diffusion method (170 ppm, 100 ppm and 30 ppm). ZnO nanoparticles can be a potential antimicrobial agent due to its low cost of production and high effectiveness in antimicrobial properties, which may find wide applications in various industries to address safety issues. Stable ZnO nanoparticles were prepared and their shape and size distribution characterized by Dynamic light scattering (35.7 nm) and transmission electron microscopic TEM study for morphology identification (20 nm), UV-visible spectroscopy (230 nm), X-ray diffraction (FWHM of more intense peak corresponding to 101 planes located at $36.33^{\circ}$ using Scherrer's formula), FT-IR (Amines, Alcohols, Carbonyl and Nitrate ions), Zeta potential (-28.8). The antimicrobial activity of ZnO nanoparticles was investigated against Bacteria and Fungi present in drinking water PVC pipelines biofilm. In these tests, Muller Hinton agar plates were used and ZnO nanoparticles of various concentrations were supplemented in solid medium.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1467-1472
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• 2003

Fouling of heat exchangers is generated by water-borne deposits, commonly known as foulants including particulate matter from the air, migrated corrosion produces; silt, clays, and sand suspended in water; organic contaminants; and boron based deposits in plants. This fouling is known to interfere with normal flow characteristics and reduce thermal efficiencies of heat exchangers. This paper focuses on fouling analyses for six heat exchangers of two primary systems in two nuclear power plants; the regenerative heat exchangers of the chemical and volume control system and the component cooling water heat exchangers of the component cooling water system. To analyze the fouling for heat exchangers, fouling factor was introduced based on the ASME O&M codes and TEMA standards. Based on the results of the fouling analyses, the present thermal performances and fouling levels for the six heat exchangers were predicted.

• 원예과학기술지
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• 제30권4호
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• pp.442-448
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• 2012

최근 상추와 같은 농산물에 의한 식중독사고가 발생하고 있으며 그 원인으로 병원성 미생물에 오염된 퇴비, 관개용수의 사용이라고 보고되고 있다. 따라서 본 연구는 육묘단계의 상토, 재배과정의 토양, 관개용수의 Escherichia coli와 Bacillus cereus 오염이 상추의 안전성에 미치는 영향을 구명하고자 수행하였다. 이를 위하여 상토는 두 균주로 7.5log CFU/g 수준으로 오염시킨 후 상추종자를 파종하고 28일간 생육시켰고, 오염되지 않은 토양과 6.0log CFU/g 수준으로 오염시킨 토양에 오염된 상토에서 21일간 자란 묘를 이식하고 49일간 인공기상동 ($25^{\circ}C$, 상대습도 70-80%)에서 생육시켰다. 또한 8.0log CFU/mL로 오염된 관개용수로 지표면관수법과 살수관수법으로 상추에 관수하고 40일간 병원성 미생물의 오염 및 생존을 조사하였다. 그 결과 육묘기의 상토와 상추 중 E. coli와 B. cereus는 시간이 경과함에 따라 점차 감소하였지만 육묘기 내내 생존 가능한 것으로 확인되었다. 토양에서는 42일간 E. coli와 B. cereus가 6.0log CFU/g 내외로 유의적인 감소 없이 유지되고 있었다. 오염된 토양에 이식된 상추는 21일째까지 E. coli와 B. cereus의 농도가 4.0log CFU/g 이상 유지되었고 이식 후 42일까지도 검출되었다. 또한 살수관수법으로 처리한 구에서 지표면관수법으로 처리한 구보다 상추의 오염수준이 5.0log CFU/g 정도 높았다. 따라서 본 연구의 결과는 병원성미생물에 오염된 상토, 토양, 관개용수는 농산물의 병원성미생물 오염에 직접적인 원인이 될 수 있음을 시사한다.