• 제목/요약/키워드: cold period

검색결과 971건 처리시간 0.025초

봉약침액(蜂藥鍼液)의 안정성(安定性) 연구(硏究) (A Study on the Stability of Diluted Bee Venom Solution)

  • 강미숙;변임정;이성노;김기현
    • 대한약침학회지
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    • 제6권2호
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    • pp.105-111
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    • 2003
  • Objective : The purpose of this study was to investigate the stability of bee venom according to the keeping method and period. Method : The author observed microbial contamination of bee venom in nutrient agar, broth, YPD agar and YPD media and antibacterial activity for S. aureus, E. coli manufactured 12, 6 and 3 months ago as the two type of room temperature and $4^{\circ}C$ cold storage. Results : 1. 1:3,000 and 1:4,000 diluted bee venom solution did not show microbial contamination both room temperature and cold storage within twelve months. 2. There was antibacterial activity of diluted bee venom for S. aureus in cold storage within twelve months and there was no antibacterial activity of diluted bee venom for S. aureus in twelve months, room temperature storage. 3. We could not observe the zone of inhibition around paper disc of all for E.coli. in 1:3,000, 1:30,000 and 1:3,000,000 diluted bee venom solution, respectively. According to results, we expect that diluted bee venom solution is stable both cold and room temperature storage within twelve months.

스파크 점화기관에서 이차 공기 분사가 냉시동시 THC 배출량에 미치는 영향에 관한 실험적 연구 (Experimental Study of the Effect of Secondary Air Injection on the Cold Start Total Hydrocarbon Emissions in a Spark Ignition Engine)

  • 이승재;함윤영;전광민
    • 한국자동차공학회논문집
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    • 제11권1호
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    • pp.1-6
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    • 2003
  • Engine emission regulations are becoming more stringent nowadays. In cold transient regime, about 80% THC is exhausted to the atmosphere in the first 200s (US FTP cycles). Accordingly, reducing emission levels in the cold period immediately after the engine start before the catalysts reach their working temperature will be an especially critical factor in meeting more stringent regulations in the future. In this study, the total hydrocarbon quantities are measured using a Fast FID with gasoline fuel for a 4-cylinde. Sl engine, including Secondary Air Injection (SAI) system. Commercial SAI device's direction is reverse to the exhaust flow. In this study, a swirl flow type SAI system which is positioned between the exhaust manifold and exhaust port, was developed. We compared the swirl type secondary air injection with a commercial secondary air injection of .everse flow. The swirl type SAI showed better results in reducing HC by 26% than the commercial flow type SAI of reverse flow which was caused by the better mixing between the exhaust gas and the secondary air.

보온력 차이에 따른 방한복 상의의 인체착의 생리반응 (Physiological Responses of Cold Protective Clothing with Different clo Value)

  • 이정숙;김희은;송민규
    • 한국의류산업학회지
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    • 제10권5호
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    • pp.683-689
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    • 2008
  • The purpose of this study was to investigate physiological responses such as rectal temperature, skin temperature, micro climate, sweat rate and subjective sensations using cold protective clothing with five different clo value. The clo value was measured by thermal manikin in windless condition. Healthy five 20's males volunteered as subjects for wearing trial experiment. The climate chamber was controlled at $50^{\circ}C$, 65% RH. The experiment consisted of repeated exercise and recovery periods. We found that the higher clo value has, the higher mean skin temperature, micro climate and sweat rate show. They felt warm and wet with higher insulation clothing. Thermal comfort increased in the last recovery period after exercise. There was significant difference between five cold protective clothing. In correlation analysis of clo value, it showed that correlation coefficient(r) values were more than 0.8. Therefore, in terms of clothing insulation, we found that correlation between thermal manikin experiment and wearing trial experiment was high. Clothing insulation could be variable according to many factors such as body movement, covering area, clothing gap, layering and design. Considering the body movement, we thought that insulation measurement need to carry out both thermal manikin experiment and wearing trial experiment.

이중버블시트를 이용한 단열양생공법의 한중콘크리트 현장적용 (Field Application of Insulation Curing Method with Double Bubble Sheets Subject to Cold Weather)

  • 홍석민;백대현;김종;전충근;한민철;한천구
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2008년도 춘계 학술논문 발표대회
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    • pp.57-60
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    • 2008
  • This study investigated the results of insulation heat curing method using double layer bubble sheet in slab concrete and mass concrete in cold weather environment. First of all, when double bubble sheets are applied, it was shown that slab concrete was protected from early freezing by remaining between 6 and 15℃ even in case outside temperature drops -9℃ below zero until the 2nd day from piling, and in the case of mass concrete, with the maximum temperature difference between the center and surface less than 4℃, crack occurrence index was close to 2 and no hydration heat crack occurred by internal constraint. The insulation heat preservation curing method using the double bubble sheet applied in this field prevented early freezing owing to stable curing temperature management, deterring concrete strength development delay at low temperature, and obtained the needed strength. Also, it was proven that the method is highly effective and economic for cold weather concrete quality maintenance through curing cost reduction like construction period shortening and labor cost reduction, etc by reducing the process of temporary equipment installation and disassembling.

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COMPARISON OF HYDROCARBON REDUCTION IN A Sl ENGINE BETWEEN CONTINUOUS AND SYNCHRONIZED SECONDARY AIR INJECTIONS

  • Chung, S.-H.;Sim, H.-S.
    • International Journal of Automotive Technology
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    • 제3권1호
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    • pp.41-46
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    • 2002
  • Effect of secondary air injection (SAI) on hydrocarbon reduction has been investigated in a single cylinder Sl engine operating at cold-steady/cold-start conditions. The hydrocarbon emission and exhaust gas temperature with and without catalytic converter were compared with continuous and synchronized SAIs, which injected secondary air intermittently into exhaust port. Effects of SAI location, SAI pressure, SAI timing, and location of catalytic converter have been investigated and the results are compared for both SAls with base condition. At cold-steady condition, the rate of HC reduction increased as the location of SAI was closer to the exhaust valve for both synchronized and continuous SAls. The emission of HC decreased with increasing exhaust-A/F when it was rich, and was relatively insensitive when it was lean. The timing of SAI in synchronized SAI had significant effect on HC reduction and exhaust gas temperature and the synchronized SAI was found to be more effective in HC reduction and exhaust gas temperature compared to the continuous SAI . At cold-start condition, when the catalytic converter was located 20 cm downstream from the exhaust port exit, the catalytic converter warm-up period for both SAls decreased by about 50%, and the accumulated hydrocarbon emission during the first 120 s decreased about by 56% and 22% with the synchronized and continuous SAIs, respectively, compared to that of the base condition.

한중콘크리트의 현장 표면단열 양생공법 시공사례 연구 (Field Application of Surface Insulation Curing Method to Cold Weather Concreting)

  • 김종백;임춘근;한민철;김성수;한천구
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2005년도 추계 학술논문 발표대회
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    • pp.25-28
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    • 2005
  • This study investigates the field application of surface insulation curing method, which combined double layer bubble sheet(DBS) and thick-curing-material(TCM) for cold weather concreting. According to the test, deck slab, curing only upper section with DBS and TCM, does not make big different temperature history with that, curing both upper and bottom section during daily average temperature 6.5t. It is concluded that combination of DBS and TCM in only upper section can be safely cured in early period of time during cold water concreting. The field test was carried out with this favourable data. The upper deck slab was insulated by combination of DBS and TCM, and the construction was surrounded by tent. in order to protect from outside wind. The test result shows that the lowest temperature of deck slab indicated 6$ ^{circ}C $. It demonstrated that this curing method can resist early frost and save construction cost in the side of management and saving labor cost, compared with previous method. In addition, the column specimen, combined both form and bubble board, exhibited favorable temperature history, due to internal hydration heat insulation effect.

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동해남부연안 냉수대 변동과 관련된 해양환경 및 식물플랑크톤의 변동 특성 (The Relationship Between Phytoplankton Distribution and Environmental Conditions of the Upwelling Cold Water in the Eastern Coast of the Korean Peninsula)

  • 오현주;서영상;허승
    • 한국지리정보학회지
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    • 제7권4호
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    • pp.166-173
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    • 2004
  • 2001~2003년 하계에 동해남부의 기장연안에서 수온, 식물플랑크톤, 영양염류 등 자료를 분석하여 냉수대의 특이해황과 식물플랑크톤의 종조성, 클로로필-a의 일일변동과의 관계를 분석하였다. 냉수대 발생시 연안수온은 단기간내에 큰 공간 변동을 나타내었다. 연안 용승 냉수의 발달과 동시에 냉수종 식물플랑크톤이 출현하였으나, 전체적으로 다양한 종수와 개체수의 증가를 보였다. 또한, 냉수대의 일일변동에 따라 분포종과 양이 변화를 보였다.

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이중버블시트를 이용한 단열보온 양생공법의 한중콘크리트 현장적용 (Field Application of Insulation Curing Method for the Concrete applying Double Layer Bubble Sheets Subjected to Cold Weather)

  • 홍석민;손호정;오치현;한민철;한천구
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2011년도 춘계 학술논문 발표대회 1부
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    • pp.83-85
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    • 2011
  • This study investigated the results of insulation heat curing method using double layer bubble sheet in concrete in cold weather environment. First of all, when double bubble sheets are applied, it was shown that concrete was protected from early freezing by remaining between 7℃ and 3℃ even in case outside temperature drops -7℃ below zero until the 3d day from piling. The insulation heat preservation curing method using the double bubble sheet applied in this field prevented early freezing owing to stable curing temperature management, deterring concrete strength development delay at low temperature, and obtained the needed strength. Also, it was proven that the method is highly effective and economic for cold weather concrete quality maintenance through curing cost reduction like construction period shortening and labor cost reduction, etc by reducing the process of temporary equipment installation and disassembling.

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Use of ultrasound Doppler to determine tooth vitality in a discolored tooth after traumatic injury: its prospects and limitations

  • Cho, Yong-Wook;Park, Sung-Ho
    • Restorative Dentistry and Endodontics
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    • 제39권1호
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    • pp.68-73
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    • 2014
  • When a tooth shows discoloration and does not respond to the cold test or electric pulp test (EPT) after a traumatic injury, its diagnosis can be even more difficult due to the lack of proper diagnostic methods to evaluate its vitality. In these case reports, we hope to demonstrate that ultrasound Doppler might be successfully used to evaluate the vitality of the tooth after trauma, and help reduce unnecessary endodontic treatments. In all three of the present cases, the teeth were discolored after traumatic injuries and showed negative responses to the cold test and EPT. However, they showed distinctive vital reactions in the ultrasound Doppler test during the whole observation period. In the first case, the tooth color returned to normal, and the tooth showed a positive response to the cold test and EPT at 10 wk after the injury. In the second case, the tooth color had returned to its normal shade at 10 wk after the traumatic injury but remained insensitive to the cold test and EPT. In the third case, the discoloration was successfully treated with vital tooth bleaching.

이중버블시트를 이용한 단열양생공법의 한중콘크리트 현장적용 (Field Application of Insulation Curing Method with Double Bubble Sheets Subject to Cold Weather)

  • 홍석민;이일선;백대현;김종;한민철;한천구
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2009년도 춘계 학술논문 발표대회 학계
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    • pp.25-28
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    • 2009
  • This study investigated the results of insulation heat curing method using double layer bubble sheet in slab concrete in cold weather environment. First of all, when double bubble sheets are applied, it was shown that slab concrete was protected from early freezing by remaining between 5 and $l0^{\circ}C$ even in case outside temperature drops $-11^{\circ}C$ below zero until the 4nd day from piling. The insulation heat preservation curing method using the double bubble sheet applied in this field prevented early freezing owing to stable curing temperature management, deterring concrete strength development delay at low temperature, and obtained the needed strength. Also, it was proven that the method is highly effective and economic for cold weather concrete quality maintenance through curing cost reduction like construction period shortening and labor cost reduction, etc by reducing the process of temporary equipment installation and disassembling.

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