• Current Research on Agriculture and Life Sciences
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• 제15권
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• pp.69-81
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• 1997

세계적(世界的)으로 양잠지역(養蠶地域)에서 큰 피해를 주는 핵다각체병(核多角體病)은 양잠현장(養蠶現場)에서 잠실(蠶室) 잠구류(蠶具類)의 철저한 포르말린 소독에도 불구하고 예방효과가 의문시(疑問視)되는 경우가 발생하며, 이는 병원체의 존부(存否) 만으로 본 질병(疾病)의 만연(蔓延)이 설명될 수 없기 때문이라는 사실을 실험병리학적(實驗病理學的)으로 입증(立證)하였다. 핵다각체병(核多角體病)의 발생(發生)을 조장(助長)하는 불량(不良) 환경요인(環境要因)을 파악하기 위하여 1979년부터 1993년 까지 15년간 한국 일본 필리핀 등지에서 57건의 사육사례를 조사하였다. 환경상태(環境狀態)와 발병사례(發病事例)의 연관성을 분석하므로써 발병생리(發病生理)와 관련된 환경요인(環境要因)을 해명한 결과, 고름병 발생빈도(發生頻度)는 상엽육과 인공사료육 간에 비슷한 경향을 나타내었고, 잠실 잠구류의 소독(消毒)방법에서는 포르말린 소독(消毒) 여부(與否)에 따른 차이가 인정되지 않았다. 교잡종(交雜種)은 원종(原種)보다 핵다각체병(核多角體病) 발생율이 다소 높은 수준이었으며, 특히 애누에때 부터 장기간 통기불량(通氣不良)인 사육환경에서는 발병률(發病率)이 현저하게 높았다. 또한, 1993년부터 1997년 까지 5년간의 실증시험(實證試驗)에서는 잠실(蠶室) 및 잠구류(蠶具類)의 청소와 사육실의 강제순환식(强制循環式) 환기(換氣)로 사육환경을 개선하므로써 인체(人體)에 유해(有害)한 농약을 사용하지 않고도 누에 핵다각체병(核多角體病) 발생을 효율적으로 제어할 수 있음을 입증(立證)하였다.

• 대한환경공학회지
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• 제30권1호
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• pp.31-36
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• 2008

본 연구는 도시하수 처리를 위한 침지형 막 분리 활성슬러지법(membrane bioreactor: MBR) 시스템에서 막 재질 및 구조가 파울링에 미치는 영향을 조사하기 위하여, polytetrafluoroethylene(PTFE), polycarbonate(PCTE) 및 polyester(PETE)의 정밀여과 막(기공크기: 0.1 $\mu$m)을 사용하였다. 120일의 운전기간 동안 PETE막 여과속도는 다른 막들에 비해 가장 빠른 감소경향을 보였으나, 화학세정을 할수록 점차 PCTE 및 PTFE막과 유사한 여과속도 감소경향을 보였다. PETE막의 유기물 제거율이 다른 막들에 비해 약간 높게 나타났으며, 이것은 막의 빠른 파울링 발생과 밀접한 관련이 있는 것으로 판단된다. 반응조내 슬러지 상징액 및 막 여과수에 존재하는 DOC성분을 친수성 및 소수성으로 분획한 결과, 본 연구에서는 막의 친수성/소수성이 MBR 파울링에 미치는 영향이 크지 않은 것으로 나타났다. 파울링이 발생한 막들의 각종 여과저항 값을 분석한 결과, PETE막은 비가역적 파울링에 의한 영향이 다른 막들에 비하여 컸으며, 유기물 제거율에도 긍정적인 영향을 미친 것으로 판단된다.

• 한국결정성장학회지
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• 제20권2호
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• pp.85-92
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• 2010

$SF_6$ 가스는 아크방지능력과 절연 특성이 탁월하기 때문에 단열, 세척, 차폐등과 같은 여러 공업적인 영역에서 널리 사용되고 있다. 그러나 $SF_6$의 지구온난화지수는 $CO_2$의 23,900배에 달하며 3,200년 이상 공기중에 잔존한다. 이러한 이유로 하이드레이트 형성 원리를 이용하여 복합 가스에서 $SF_6$를 분리해 내는 방법이 기술적, 경제적인 면에 영향을 끼칠 것이다. 본 연구에서 $SF_6$ 하이드레이트 결정의 형성과 성장에 대한 이해를 위하여 형태학적 분석을 수행하였다. $SF_6$ 하이드레이트 필름은 용액과 기상의 계면에서 먼저 생성되었고, 이후에 수지상 가지의 형태로 성장하는 것이 관찰 되었다. 수지상 성장 결정은 기상의 방향으로 성장하였는데 이것은 객체 분자의 농도 차이에 근거한 것으로 사료된다. 본 연구에서는 기/액 계면에서의 핵생성, 유동, 성장과 같은 $SF_6$ 하이드레이트 결정의 형태학적 특성에 대하여 기술하였다.

• 대한수의학회지
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• 제44권1호
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• pp.29-40
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• 2004

Because cleaning products are part of our everyday lives, it is essential that they should not present significant risks to health. However, many petrochemicals in most soaps and detergents can be absorbed through the scalp and skin and, over time, accumulate in the organs and tissues. This accumulation may result in brain, nerve, and liver damage. Therefore, it is interested in developing non-harmful detergent. According to Korea Research Institute of Chemical Technology, GC-100X may be non-harmful and non-corrosive alkaline ionic water (pH 12). It is composed of hydroxyl radicals and supplemented with xylitol. To evaluate influence of GC-100X on rats and beagles, GC-100X was diluted with distilled water (25%, 50%, and 100% solution respectively). Each of diluted GC-100X was daily treated per oral. In body weight analysis, urinary analysis, ophthalmological test and autopsy, we did not find any significance, but in serum biochemical analysis and hematological analysis, we found some significances in middle dose group compared with control group. These significances in serum biochemical analysis and hematological analysis may be not induced by GC-100X, because it was not found to be significant from control group in histopathological examination. Thus, it is concluded that NOEL(No Observed Effect Level) of GC-100X may be higher than all treatment doses used in this study, and GC-100X may be a non-toxic detergent.

• 기본간호학회지
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• 제21권4호
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• pp.392-402
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• 2014

Purpose: This study was done to investigate the status of disinfection and sterilization in healthcare facilities. Method: A survey of 193 Korean healthcare facilities was conducted from February 8 to March 7, 2013. Data were analyzed using descriptive statistics, ${\chi}^2$ test, Fisher's exact test, one-way ANOVA, Scheffe with SPSS WIN 18.0. Results: Of the healthcare facilities 93.2% had specific guidelines for disinfection/sterilization, but only 47.9% had a committee on disinfection/sterilization for decision-making, less than half (42.7%) conducted regular monitoring of actual practices, while 83.9% had established procedures for recovery in case of problems with the disinfection process and 89.0% kept records and archives of disinfection practices. Cleaning process, selection of chemical disinfectants and process of disinfection and sterilization were found to be inadequate in some healthcare facilities. Perception score for adequacy of medical instruments was 8.10, environmental disinfection was 7.20, and sterilizer management was 8.45 out of a possible 10. Conclusion: Compared to larger institutions, smaller healthcare facilities had less effective disinfection and sterilization management systems, while some facilities showed inadequate practices for medical equipment and general sterilization. Better academic and state-level support is recommended for smaller facilities in order to establish a better system-wide management system.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.150.1-150.1
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• 2014

Showerhead is used as a main part in the semiconductor equipment. The face plate flatness should remain constant and the cleaning performance must be gained to keep the uniformity level of etching or deposition in chemical vapor deposition process. High operating temperature or long period of thermal loading could lead the showerhead to be deformed thermally. In some case, the thermal deformation appears very sensitive to showerhead performance. This paper describes the methods for robust design using computational fluid dynamics. To reveal the influence of the post distribution on flow pattern in the showerhead cavity, numerical simulation was performed for several post distributions. The flow structure appears similar to an impinging flow near a centered baffle in showerhead cavity. We took the structure as an index to estimate diffusion path. A robust design to reduce the thermal deformation of showerhead can be achieved using post number increase without ill effect on flow. To prevent the showerhead deformation by heat loading, its face plate thickness was determined additionally using numerical simulation. The face plate has thousands of impinging holes. The design key is to keep pressure drop distribution on the showerhead face plate with the holes. This study reads the methodology to apply to a showerhead hole design. A Hagen-Poiseuille equation gives the pressure drop in a fluid flowing through such hole. The assumptions of the equation are the fluid is viscous-incompressible and the flow is laminar fully developed in a through hole. An equation can be expressed with radius R and length L related to the volume flow rate Q from the Hagen-Poiseuille equation, $Q={\pi}R4{\Delta}p/8{\mu}L$, where ${\mu}$ is the viscosity and ${\Delta}p$ is the pressure drop. In present case, each hole has steps at both the inlet and the outlet, and the fluid appears compressible. So we simplify the equation as $Q=C(R,L){\Delta}p$. A series of performance curves for a through hole with geometric parameters were obtained using two-dimensional numerical simulation. We obtained a relation between the hole diameter and hole length from the test cases to determine hole diameter at fixed hole length. A numerical simulation has been performed as a tool for enhancing showerhead robust design from flow structure. Geometric parameters for the design were post distribution and face plate thickness. The reinforced showerhead has been installed and its effective deposition profile is being shown in factory.

• 보존과학회지
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• 제27권4호
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• pp.441-450
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• 2011

이 연구는 토기 재질과 토양 특성에 따라 매장환경이 출토 토기에 미치는 물리화학적 영향을 연구하였다. 이를 위해 대전 학하, 아산 음봉, 화성 소근산 그리고 공주 행정중심복합도시 출토 토기와 토양을 연구 대상으로 하였다. 먼저 토기의 탈염을 통해 용출되는 이온의 화학종과 용출속도를 조사한 결과, 토기의 기공크기와 흡수율에 따라 토기 내 이온유입이 달라졌다. 즉 $1,000^{\circ}C$ 이상의 고온 소성된 토기는 기공이 작고 흡수율이 낮아 매장환경의 염 유입 현상이 거의 일어나지 않았다. 그러나 $800^{\circ}C$ 이하의 저온 소성된 토기는 기공이 크고 흡수율이 높아 다량의 염이 유입되어 증류수 탈염을 통해 염을 제거하였다. 탈염 2일 만에 40~60%의 염이 제거되었고 탈염 1주일 만에 60~80%의 염이 제거되었다. 또한 토양에 포화되어 있는 이온은 대부분 토기에도 동일한 비율로 존재하고 $K_2SO_4$와 같이 토양에 잔존하는 비료의 성분도 검출되었다. 그러나 모래 함량이 상당히 높은 사질 토양시료에서는 함유 이온량이 적어 토기에 유입되는 이온의 영향이 비교적 적었고 미사 및 점토 함량이 높은 토양에 매장되었던 토기는 유입되는 이온함량이 높았다. 그러나 저온소성된 토기에서는 다량 유입된 염에 의한 손상이 우려되므로 세척 이외의 탈염을 통한 염 제거가 필요하며 그 기간은 토기의 상태에 따라 달라질 수 있을 것으로 생각된다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제10권2호
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• pp.28-34
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• 2005

본 논문은 유류로 오염된 부지를 DSB(Deep-site Biopile) system을 이용하여 정화함으로써 적용 가능한 현장특성을 평가하기 위한 것이다. 오염부지는 유류가 유출되어 깊이 약 2.5 m 부근에 위치하는 지하수의 흐름에 띠라 광범위하게 오염(총 $7,201m^3$) 되어 있었으며, 투수성이 좋은 Sand층으로 구성되어 있다. 부지 내 설치된 배관은 각 지점마다 독립적으로 제어될 수 있도록 하였으며, DSB system의 가동은 24시간을 기준으로 30분 가동/30분 정지되도록 하였다. 오염부지 내 오염원이 저감되는 현황을 파악하기 위하여 DSB system 가동시간에 따른 시료채취 작업을 수행한 결과, DSB system 가동 후 약 30여일 만에 총석유계탄화수소 및 BTEX 오염원이 약 50% 이상 저감되었으며 약 165일이 경과한 후에는 토양오염 확인기준 이하로 저감되어 정화작업이 정상적으로 완료되었다. 이와 같이 본 DSB system은 기존에 적용되어 왔던 생물학적 공법들과는 달리 높은 농도의 유류화합물로 오염되어 있는 토양 및 지하수를 약 6개월의 단기간에 효과적으로 처리할 수 있었으며 정화 system을 지상이 아닌 지중에 설치함으로써 별도의 부지가 확보되지 않은 경우에도 적용할 수 있는 특성이 있음을 알 수 있었다.

• 대한치과보철학회지
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• 제44권3호
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• pp.284-294
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• 2006

Statement of problem. Proliferation of Candida albicans is primarily within the plaque on the fitting surface of the denture rather than on the inflamed mucosa. Consequently, the treatment of the denture is equally important as treatment of the tissue. Cleansing and disinfection should be efficiently carried-out as the organisms can penetrate into the voids of the acrylic resin and grow in them, from which they can continue to infect and reinfect bearing tissues. Purpose. The purpose of this study was to evaluate the applicability of photocatalytic reaction to eliminate Candida albicans from acrylic resin denture base, and to investigate the anti-fungal effect with various UVA illumination time. Materials and Methods. The specimens were cured by the conventional method following the manufacturer's instruction using thermal polymerized denture base resin (Vertex RS: Dentimex, Netherlands). $TiO_2$ photocatalyst sol(LT), which is able to be coated at normal temperature, was made from the Ti-alkoxide progenitor. The XRD patterns, TEM images and nitrogen absorption ability of the $TiO_2$ photocatalyst sol(LT) were compared with the commercial $TiO_2$ photocatalyst P-25. The experimental specimens were coated with the mixture of the $TiO_2$ photocatalyst sol(LT) and binder material (silane) using dip-coater, and uncoated resin plates were used as the control group. Crystallinity of $TiO_2$ of the specimen was tested by the XRD. Size, shape and chemical compositions were also analyzed using the FE-SEM/ EDS. The angle and methylene blue degradation efsciency were measured for evaluating the photocatalytic activity of the $TiO_2$ film. Finally, the antifungal activity of the specimen was tested. Candida albicans KCTC 7629(1 ml, initial concentration $10^5$ cells/ ml) were applied to the experiment and control group specimens and subsequently two UVA light source with 10W, 353 nm peak emission were illuminated to the specimens from 15cm above. The extracted $2{\mu}l$ of sample was plated on nutrient agar plate ($Bacto^{TM}$ Brain Heart Infusion; BD, USA) with 10 minute intervals for 120 minute, respectively. It was incubated for 24 hours at $37^{\circ}C$ and the colony forming units (CFUs) were then counted. Results. Compared the characteristics of LT photocatalyst with commercial P-25 photocatalyst, LT were shown higher activity than P-25. The LT coated experimental specimen surface had anatase crystal form, less than 20 nm of particle size and wide specific surface area. To evaluate the photocatalytic activity of specimens, methylene blue degradation reaction were used and about 5% of degradation rate were measured after 2 hours. The average contact angle was less than $20^{\circ}$ indicating that the LT photocatalyst had hydrophilicity. In the antifungal activity test for Candida albicans, 0% survival rate were measured within 30 minute after irradiation of UVA light. Conclusion. From the results reported above, it is concluded that the UVA-LT photocatalytic reaction have an antifungal effect on the denture surface Candida albicans, and so that could be applicable to the clinical use as a cleaning method.

• Safety and Health at Work
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• 제4권3호
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• pp.142-148
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• 2013

Background: To elucidate the relationship between seven occupational dermatoses (ODs) and 20 types of work in Greece. Methods: This was a prevalence epidemiologic study of certain ODs among 4,000 workers employed in 20 types of enterprise, in 104 companies, in 2006-2012, using data from company medical records, questionnaires, occupational medical, and special examinations. The ${\chi}^2$ test was applied to reveal statistically significant relationships between types of enterprises and occurrence of ODs. Results: A high percentage (39.9%) of employees included in the study population suffered from ODs. The highest prevalence rates were noted among hairdressers (of contact dermatitis: 30%), cooks (of contact dermatitis: 29.5%), bitumen workers (of acne: 23.5%), car industry workers (of mechanical injury: 15%), construction workers (of contact urticaria: 29.5%), industrial cleaning workers (of chemical burns: 13%), and farmers (of malignant tumors: 5.5%).We observed several statistical significant correlations between ODs (acute and chronic contact dermatitis, urticaria, mechanical injury, acne, burns, skin cancer) and certain types of enterprises. There was no statistically significant correlation between gender and prevalence of ODs, except for dermatoses caused by mechanical injuries afflicting mainly men [${\chi}^2(1)=13.40$, p < 0.001] and for chronic contact dermatitis [${\chi}^2(1)=5.53$, p=0.019] afflicting mainly women. Conclusion: Prevalence of ODs is high in Greece, contrary to all official reports by the Greek National Institute of Health. There is a need to introduce a nationwide voluntary surveillance system for reporting ODs and to enhance skin protection measures at work.