• 한국환경보건학회지
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• 제42권4호
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• pp.266-273
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• 2016

Objectives: This study evaluated the virucidal efficacy against avian influenza virus (AIV) of a disinfectant spray containing 0.25% grapefruit seed extract, 0.2% citric acid, 0.0625% malic acid and 0.0125% benzalkonium chloride. Methods: The disinfectant spray was diluted several times with hard water (HW) and organic matter (OM). Two point five mL of each diluent was added into each test tube, and 2.5 mL of AIV suspension was inserted into each test tube. After 30 minutes of virus-disinfectant contact reaction at $4^{\circ}C$, 2.5 mL of 10% inactivated fetal bovine serum was added into each test tube to neutralize the sanitizer efficacy. The neutralized solutions were serial 10-fold dilutions with phosphate buffer solution, and 0.2 mL of the diluents was injected into the allantoic cavity of five ten-day-old-chickens per dilution time. After incubation of the embryos for five days, the viability of the AIV was examined by hemagglutination titer. The valid dilution of the disinfectant spray was estimated according to the dilution time that the virus titer was inactivated more than $10^4$ 50% egg-infective dose (EID50)/mL compared with pathogen control. Results: In HW and OM conditions, the valid dilutions of the disinfectant spray against AIV were seven- and three-fold dilutions, respectively. The AIV titer of the pathogen control was more than 6.1 log10EID50/mL, and there was no embryonic toxicity. Conclusion: The present study showed that this disinfectant spray has effective virucidal activity against AIV.

• 정신신체의학
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• 제25권1호
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• pp.33-45
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• 2017

연구목적 본 연구는 군복무 적합성에 대한 정밀평가 및 병사용 진단서를 목적으로 정신건강의학과에 내원한 환자군의 심리적 특성을 확인하고자, 일반적인 정신과적 치료를 위해 내원한 환자군과의 비교를 통해 차이를 분석하였다. 방법 정신건강의학과에 내원한 18세에서 27세까지의 남성환자 총 319명을 병사용 진단군 165명과 일반내원군 154명으로 분류하였다. 독립표본 t-test, ANCOVA, 절단점을 초과하는 사례수에 대한 ${\chi}^2$ 검정을 통해 두 집단 간 MMPI-2-RF의 척도들의 차이를 비교하였다. 결과 두 집단 간 연령 및 교육수준의 차이가 유의하였다. 두 집단은 MMPI-2-RF의 타당도 척도, 상위차원척도, 재구성 임상척도, 특정문제척도, 성격병리 5요인척도 모두에서 차이가 있었다. 두 집단 간 차이를 조사하기 위해 시행한 세가지 분석 모두에서 유의한 차이를 보인 척도는 EID, RC7, HLP, SFD, SAV, SHY, DSF, INTR-r이었다. 결론 군복무 적합성 평가가 의뢰된 환자군의 경우, 일반내원 환자군에 비해 정서적 고통의 수준이 유의하게 높았으며, 무력감이나 자신감 저하, 대인관계에서의 어려움이 더욱 현저한 것으로 시사되었다. 더불어 병사용 진단 군에서 보인 타당도 척도의 상승을 고려하여 향후 연구에 대한 제언을 하였다.

• 한국동물위생학회지
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• 제36권3호
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• pp.163-169
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• 2013

Both of avian influenza (AI) and Newcastle disease (ND) can cause mild to severe diease in poultry. In this study, clinical signs, macro, and micro lesions were studied. Eighteen six-week-old SPF chicks were divided into 4 groups (E1, E2, E3 and C1) and housed in different rooms of the isolation facility at CAVAC (Daejeon, Korea). The control group (C1) of 3 chicks was housed separately as uninoculated. Experimental groups (E1, E2 and E3) challenged with H9N2 and/or NDV. E1 group was challenged with 0.1 mL A/Kr/Ck/01310/01 (H9N2) $10^{5.6}$ $EID_{50}$ by intranasal, E2 group was challenged with 0.5 mL Kyojeongwon (KJW) $10^{5.0}{\sim}10^{6.0}$ $ELD_{50}$ by intramuscular, and E3 group was challenged with 0.1 mL A/Kr/Ck/01310/01 $10^{5.6}$ $EID_{50}$ by intranasal and 0.5 mL KJW $10^{5.0}{\sim}10^{6.0}$ $ELD_{50}$ by intramuscular 7 days after H9N2 challenge. In clinical signs and gross findings, E1 group showed 0% mortality, anorexia, and hemorrhage of proventriculus and thymus, E2 group showed 100% mortality within 3~5 days after challenge, anorexia, green diarrhea, hemorrhage of proventriculus, proximal esophagus and thymus, enlargement of kidney, and bronze liver, and E3 group showed 100% mortality within 24~36 hours after NDV challenge, depression, anorexia, green diarrhea, hemorrhage of proventriculus, spleen, and lung, enlargement of kidney, and reduction of thymus size and number. In histopathological examination, E1 group showed depletion and necrosis in bursa of Fabricius, thymus, and spleen, and E2 and E3 group showed severe lymphocyte depletion and necrosis with destruction of lymphoid organ structures. In conclusion, co-infection of H9N2 with ND virus causes acute disease with high mortality than single infection and the pathologic lesions were more severe.

• 한국가금학회지
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• 제17권3호
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• pp.225-232
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• 1990

실용 산란계 병아리에 대해서 시중에서 유통되고 있는 B$_1$생독 뉴캣슬병백신의 효능을 접종방법과 접종횟수를 달리하여 비교하였다. 실용산란계 372수를 93수씩 4군으로 나눈 후 3군에 대해서는 각각 음수. 점안, 분무방법으로 28일령까지 3회에 걸쳐 백신을 접종하였고 나머지 1군은 백신을 접종하지 않은 대조군으로 하였다. 매회 백신접종 2준 4주 후에 강독 바이러스로 공격접종하여 방어율을 조사하고 2주 간격으로 채혈하여, 혈구응집억제(HI) 항체가를 조차하였다. 방어율은 1일령에 1회 접종하는 것보다 2회 또는 3회 접종하는 것이 높았으나 2회. 3회간에는 큰 차이가 없었다. 접종방법간에는 분무방법이 2회 이상 접종할 경우 방어율이 높았으며 다음은 점안, 음수 순이었다. 백신을 2회 또는 3회 접종하여도 HI항체가는 대조군에 비해 크게 상승하지 않았다. 전반적으로 방어율이 낮은 것은 백신의 역가가 낮기 때문으로 생각되었다. 공격접종 후 뉴캣슬병 임상증상은 84% 이상에서 원기 및 식욕저하와 기면을 보였고 27%에서 설사, 15%에서 호홉곤란, 10%에서는 사경을 보였다. 부견소견상 출혈반은 십이지장(51%), 기관(36%), 회장(13%), 맹장편도(11%), 선위(10%) 순으로 관찰되었다.

• Journal of Power Electronics
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• 제6권4호
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• pp.290-297
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• 2006

Various methods have been discussed to reduce detent force in a tubular permanent magnet type linear single phase AC generator. In particular, the proposed methods depend on variations of the permanent magnet construction. These methods include two approaches in the form of sloped magnets, and conical magnets in addition to the conventional method of optimizing the magnet length. The undesired detent force ripples were calculated by a two dimensional Finite Element Method (FEM). Moreover, the generated electromotive force in the stator coils was calculated for each configuration of the permanent magnet. The experimental results agreed well with those obtained from the FEM-based simulations. Sufficient reduction in the detent force was achieved over the range of 40% while the root mean square of the output voltage was maintained. It was found that sloping the permanent magnet decreased the detent force and at the same time increased the generated rms voltage of the AC generator. The performance of the designed linear AC generator was evaluated in terms of its efficiency, total weight, losses, and power to weight ratio.

• Safety and Health at Work
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• 제7권4호
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• pp.363-371
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• 2016

Background: Seafaring is an inherently stressful environment. Because working time and leisure time is spent in the same confined environment for a prolonged period of time, many stressors present in seafaring can also be conceived of as chronic. We explored the effects of duration at sea, seafaring experience, environmental stressors, and psychological capital (PsyCap) on the sleep quality and fatigue of seafarers. PsyCap is a construct that draws upon ideas from positive psychology and positive organizational behavior, and is intended to capture an individual's psychological capacities that can be developed and utilized for performance improvements. Methods: We collected survey data from a sample of seafarers working in the offshore re-supply industry (n = 402) and a sample of seafarers working on board combined passenger and cargo ships (n = 340). Results: PsyCap emerged as a robust predictor with statistically significant relations to fatigue and sleep quality in both samples. PsyCap also interacted with duration at sea in explaining fatigue in seafarers working on board the passenger and cargo ships. Seafarers on passenger and cargo ships also reported significantly higher levels of fatigue than those working in the offshore re-supply industry. Conclusion: Coupled with emerging research showing that PsyCap is trainable, our results suggest that maritime organizations could have much to gain by being cognizant of and developing routines for continually developing the PsyCap of their employees.

• 대한인간공학회지
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• 제29권4호
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• pp.661-665
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• 2010

Current subway station's office employee must perform safety management tasks by monitoring the various safety management systems. But these monitoring systems are limited in effective situational awareness and response to a state of emergency immediately. It is necessary to develop an integrated safety management system display. In this study, we developed subway station safety management system's (CCTV, fire detection & alarm system, screen door control equipment) integrated prototype display with ecological interface design framework and evaluated prototype display interface's usability with GOMS model. The result was that the ecological interface's performance was better than existing safety management system's interface.

• Advances in environmental research
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• 제2권1호
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• pp.35-49
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• 2013

Research work on removal of fluoride from water, referred to as water defluoridation, has resulted into the development of a number of technologies over the years but they suffer from either cost or efficiency drawbacks. In this work, enhancement effects of phosphate and silicate on defluoridation of water by low-cost Plaster of Paris (calcined gypsum) were studied. To our knowledge, the influence of silicate on defluoridation was not reported. It was claimed, that the presence of some ions in the treated water samples, was decreasing the fluoride removal since these ions compete the fluoride ions on occupying the available adsorption sites, however, phosphate and silicate ions, from its sodium slats, have enhanced the fluoride % removal, hence, precipitation of calcium-fluoro compounds of these ions can be suggested. Percentage removal of $F^-$ by neat Plaster is 48%, the electrical conductance (EC) curve shows the typical curve of Plaster setting which begins at 20 min and finished at 30 min. The addition of phosphate and silicate ions enhances the removal of fluoride to high extent > 90%. Thermodynamics parameters showed spontaneous fluoride removal by neat Plaster and Plaster-silicate system. The percentage removal with time showed second-order reaction kinetics.

• 한국동물위생학회지
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• 제24권2호
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• pp.147-159
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• 2001

This Study was conducted to determine vaccination programs for the control of Newcastle Disease(ND) in chickens and investigate protective effect against Newcastle disease virus (NDV) after live ND vaccination. Maternal HI antibody titer level of chickens according to day(age) 1, 7, 14, 21, 28 and 35 were decreased gradually as 7.10$\pm$0.74, 6.57$\pm$0.74, 3.71$\pm$1.25, 2.20$\pm$1.03, 1.20$\pm$1.23 and 0.50$\pm$0.71. As a result of HI test and ELISA, both chickens vaccinated with VG/GA strain live vaccine at 1-day-old and chickens not vaccinated do not have antibody titer for protection against NDV at 14-day-old. Except for LaSota strain vaccine, in case of vaccination with VG/GA spray and VG/GA, B1 and LaSota strain drinking water at 14-day-old, the protective effect was 100% in chickens inoculated NDV($10^{7.2}$ $EID_{50}$/50${\mu}\ell$, eye drop) at 21-day-old, but not 10～50% at 28-day-old. These data suggest that live NDV vaccination should be given at 10-day-old 20-25day-old for protect against NDV at periodic outbreaks of ND caused by velogenic viscerotropic NDV in the environment of a farm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.134-139
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• 2005

This paper presents a cost effective quasi-resonant soft-switching PWM high frequency inverter with minimum circuit components. This inverter can achieve wider soft commutation, simpler power circuit configuration, smaller volumetric size, lower cost and wider power regulation range, higher-efficiency as compared with single ended quasi-resonant ZVS-PFM inverter and active voltage clamped quasi-resonant ZVS-PWM inverter. The operation principle of the proposed inverter is described on the basis of the simulation and experimental results, together with its operating performances in steady state. The operating performances of this unique proposed high frequency inverter based on ZVS and ZCS arms-related soft commutation principle is evaluated and discussed as compared with the active voltage-clamped ZVS-PWM inverter and a conventional single-ended ZVS-PFM inverter. The practical effectiveness of a novel type quasi-resonant soft-switching PWM high frequency inverter using IGBT is actually proved for consumer induction heated appliances as rice cooker, hot water producer, steamer and super heated steamer. The extended bidirectional circuit topology of quasi-resonant PWM high frequency inverter with minimum circuit components is demonstrated, which operate as the direct frequency changer.