• 설비공학논문집
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• 제22권10호
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• pp.697-703
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• 2010

In recent semiconductor manufacturing clean rooms, air washers are used to remove airborne gaseous contaminants from the outdoor air introduced into a clean room. Meanwhile, there is a large amount of exhaust air from a clean room. From an energy conservation point of view, heat recovery is useful for reducing the outdoor air conditioning load required to maintain a clean room. Therefore it is desirable to recover heat from the exhaust air and use it to cool or heat the outdoor air. In the present study, numerical analysis was conducted to evaluate the recovered heat of an exhaust air heat recovery type air washer system, which is the key part of an energy saving outdoor air conditioning system for semiconductor clean rooms. The present numerical results showed relatively good agreement with the available experimental data.

• Restorative Dentistry and Endodontics
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• 제28권3호
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• pp.203-208
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• 2003

The purpose of this study was to evaluate the effect of salivary contamination of teeth on bonding efficacy of self-priming and self-etching DBSs. The materials used were Single Bond(SB, self-priming system, 3M), Unifil Bond(UB, self-etching system, GC), and Scotchbond Multi-Purpose Plus(SM, 3M) as control. Forty five human molars randomly allocated to three groups as dentin bonding systems tested and embedded in epoxy resin. Then the specimens were wet-ground to expose flat buccal enamel surface or flat occlusal dentin surface and cut bucco-lingually to form two halves with slow speed diamond saw. One of them was used under non-contamination, other under contamination with saliva. The bonding procedure was according to the manufacturer's directions and resin composite(Z-100, 3M Dental Products, St. Paul, MN) was built-up on the bonded surface 5mm high. The specimens were ground carefully at the enamel-composite interface with fine finishing round diamond bur to create an hour-glass shape yielding bonded surface areas of $1.5{\pm}0.1\textrm{mm}^2$. The specimens were bonded to the modified microtensile testing apparatus with cyanoacrylate, attached to the universal testing machine and stressed in tension at a CHS of 1mm/min. The tensile force at failure was recorded and converted to a tensile stress(MPa). Mean values and standard deviations of the bond strength are listed in table. One-way ANOVA was used to determine significant difference at the 95% level. The bond strength of SBMP and SB were not affected by salivary contamination, but that of UB was significantly affected by salivary contamination. These results indicate that DBSs with total etch technique seems less likely affected by salivary contamination in bonding procedure.

• Journal of Power Electronics
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• 제11권5호
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• pp.751-758
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• 2011

This paper presents an effective robust predictive control scheme for the active power filter (APF) using a smith-predictor based current regulator, which show superior features when compared to proportional-integral (PI) controllers in terms of an enhanced closed-loop bandwidth and an improved current tracking accuracy. A moving average filter (MAF) is implemented using a field programmable gate array (FPGA) for signal pre-processing to eliminate the switching ripple contamination. An adaptive linear neural network (ADALINE) is used for individual harmonic estimation to achieve selective compensation purpose. The effectiveness and validity of the devised control algorithm are confirmed by extensive simulation and experimental results.

• 치위생과학회지
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• 제17권6호
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• pp.472-480
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• 2017

치과의료기관 의료장비 표면 및 치과위생사 손의 S. epidermidis 오염도 조사를 위해 2017년 7월부터 8월까지 일부지역 20개 치과의원에서 치과위생사 20인의 손 오염, 치과별 7부위 표면 140부위의 S. epidermidis 오염도를 조사하였다. S. epidermidis 오염도는 핸드플레이트와 로닥플레이트를 사용하였으며, $35^{\circ}C$ 24시간 배양하였다. 손 오염도는 핸드플레이트 기준에 근거하여 저, 중, 고 그룹으로 분류한 후 그룹별 손 부위별 오염도를 ANOVA 분석하였다. 의료장비 표면 오염수준은 집락을 계수하여 기술통계 하였다. 치과위생사 55%는 중등도 이상의 손 오염이 있었고, 부위별로는 손바닥이 29.45 CFU로 가장 높게 나타났으며, 그 다음으로는 중지 7.8 CFU, 약지 6.4 CFU, 엄지 6 CFU 순서였다. 의료장비 표면 오염도 조사결과 3-way 손잡이 4.45 CFU, 컴퓨터 마우스 3.37 CFU, 거울 손잡이 1.60 CFU로 다른 영역보다 높게 조사되었다. 손 오염도가 높은 집단일수록 손의 S. epidermidis 오염도가 높은 양적 상관관계를 나타내었다. S. epidermidis 오염도는 의료장비 표면 오염보다 손에서 높게 나타났다. 그러므로 의료진들은 손 위생의 중요성을 인식하고 WHO에서 제시한 방법으로 손 위생을 실천하는 것이 요구되었다. 의료진들이 감염관리 업무수행에 책임감을 갖고 안전한 의료 환경을 조성할 수 있도록 감염관리 지침과 체계적인 감염관리 업무 수행에 관한 교육이 요구되었다.

• Asian-Australasian Journal of Animal Sciences
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• 제24권1호
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• pp.96-102
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• 2011

In this study, we examined the effects of formic acid administration to the drinking water on performance, intestinal microflora and carcass contamination in male broilers. A total of 312 day-old male broiler chicks were allocated to two groups with three replicates. The first group (control) received normal drinking water (pH 7.4) during the experiment. The second group consumed acidified drinking water (pH 4.5) after 5 d of age. At 43 d of age, twelve birds were randomly selected from the control group to determine the effect of acidified drinking water on carcass contamination. These birds were only given normal or acidified (pH 3) drinking water for 8 h prior to slaughter. The reduction of water pH from 7.4 to 4.5 significantly decreased body weights of male broilers at 21 and 42 d of age. However, no differences were observed between male broilers given normal and acidified drinking water in terms of feed intake, feed conversion ratio and mortality. The pH value of the gizzard contents was not significantly affected by acid water treatment. There were no significant differences in the intestinal population of E. coli, total organism and Salmonella between the groups. The total organism and E. coli counts of the carcass slightly decreased in the acidified group. No Salmonella was identified in carcass samples of any of the treatment groups. The results showed that drinking water acidification did not provide beneficial effects on performance, intestinal microflora and carcass contamination in male broilers.

• 한국동물위생학회지
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• 제30권2호
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• pp.191-196
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• 2007

The slaughter process for cattle will inevitably transfer some bacteria onto the carcasses. The goal of food safety programs is to minimize and effectively remove this contamination. This study was attempted by the Verif $EYE^{TM}$ machine-vision technology that might be useful for reducing microbial indicator counts and could reduce the contamination chance of E coli O157:H7 and Salmonella spp on beef carcasses. For the evaluation of the effectiveness of the Verif $EYE^{TM}$ technology, 80 samples were examined by the inspection device over 15 days. On an examination of FDS-positive samples compared to negative controls from the same carcasses, aerobic plate counts were bigger than the negative control samples (5.26 vs 4.60 log). Enterobacteriaceae counts were greater on the positive samples than the corresponding negative control samples (2.07 vs 1.17log). There was a consistent correlation between samples detected by the Verif $EYE^{TM}$ system with detectable counts. For example, 100% of positive samples had detectable APC and 91.2% of positive samples had detectable TCC. Therefore, if areas detected as positive for contamination by the Verif $EYE^{TM}$ system were removed from the carcasses, significant sources of microbial contamination will be reduced for objective compliance with HACCP. This results suggest that the use of Verif $EYE^{TM}$ machine-vision technology might be useful for reducing microbial indicator counts (APC, TCC) and could help reduce the risk of presence of E coJi O157:H7 and Salmonella spp on Beef carcasses.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2003년도 가을 학술논문집
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• pp.162-167
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• 2003

조사재시험시설에 설치되어 있는 풀$(3m{\times}6m{\times}10m)$은 조사재운반용 수송용기(Cask)를 풀에 하역하여 풀물 속에서 조사재(시료)를 꺼내어 핫셀 내로 반입/반출하는 목적으로 사용한다. 수송용기를 풀에 하역하여 시료를 취출시 또는 버켓 엘리베이터에 장착시 모든 작업은 육안으로 행하여지기 때문에 항상 풀물을 양호한 수준으로 관리하여 수중취급 작업을 용이하게 하여야 하며, 방사성 오염관리 측면에서는 물에 잔존해 있는 방사성물질을 원자력법령에서 정하는 규정치 이하로 관리하여야 한다. 본 논문에서는 조사재시험시설에 설치하여 운용하고 있는 풀물정화장치 운전에 의한 방사능오염 및 수질에 대한 거동을 반출입된 시료별로 오염분포를 기술하였다.

• Restorative Dentistry and Endodontics
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• 제21권2호
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• pp.585-601
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• 1996

The purpose of this study was to elucidate the effect of blood-and saliva-contamination during dentin pretreatment procedure on tensile bond strength, and to investigate the effect of contaminant-removing treatments on the recovery of bond strength of dentin bonding agents. Dentin specimens prepared from freshly extracted bovine mandibular anterior teeth were divided into non-contaminated control and contaminated experimental groups. The specimens of the contaminated group were contaminated with saliva or blood after etching or priming procedure, followed by contaminant-removing treatments. All the specimens were bonded with All Bond$^{(R)}$ 2 dentin bonding agent and Bisfil$^{TM}$ composite resin or Scotchbond$^{TM}$ Multipurpose and Z100. After all the bonded specimens were stored in $37^{\circ}C$ distilled water for 24 hours, tensile bond strengths were measured. The contaminated dentin and fractured dentin surfaces were examined under the scanning electron microscope. The results were as follows : Contaminated specimens showed lower bond strength than non-contaminated ones regardless of the kind of contaminant, contamination time and contaminant-removing treatments, except specimens which were acid-etched following saliva contamination after etching in All Bond$^{(R)}$ 2 groups (p<0.05). Blood contaminant resulted in much bond strength decrease than saliva ones (p<0.01), and contamination after priming resulted in much decrease in bond strength than after etching (p<0.01). Re-etching resulted in increase of bond strength in the specimens contaminated with saliva after etching but not in blood contaminated ones. Re-priming resulted in increase of bond strength in the specimens contaminated after priming regardless of the kind of contaminant.

• 한국가축번식학회지
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• 제19권2호
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• pp.153-157
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• 1995

These studies were conducted to investigate the microbe control effect of antibiotics treatment in all media used for in vitro fertilization(IVF) embryo production. The bovine oocytes were recovered from follicles(2~5mm) and were cultrued for 22hrs at 38.5$^{\circ}C$ with 5% CO2 incubator. The contamination and development rate in vitro fertilized oocyte was evaluated everyday. The results were summerized as follow ; 1. Control, antibiotic-antimycotic solution(AAS, Gibco) 1%＋gentamycin, and AAS 1%＋kanamycin(Sigma, USA) treatment was contaminated with 72hrs. However Baytril and Kanamycin(Korea) added was not contaminated. 2. The blastocyst formation rate in Baytril supplementated 1, 2 and 3${mu}ell$/ml was 3.73, 1.28 and 0.00%, respectively. 3. The blastocyst formation in kanamycin added concentration of 50, 75 and 100$\mu\textrm{g}$/ml was 13.0, 9.4 and 3.49%, respectively.

• 공기청정기술
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• 제15권2호통권57호
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• pp.57-57
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• 2002