• Journal of Photoscience
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• 제8권3_4호
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• pp.105-112
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• 2001

Susceptibility to low temperature photoinhibition in photosynthetic apparatus was compared among three cucumber cultivars, Gahachungjang (GH), Banbaekjijeo (BB) and Gaeryangsymji (GR). By chilling in the light for 6 h, a sustained decrease in the potential quantum yield (Fv/Fm) and the oxidizable P700 contents was observed, and the decrease was less in GH than in BB and GR. Although the difference was small, some $\Phi_{PSII}$ remained in GH after light-chilling for 6 h indicating that a few electrons can flow around photosystem II(PSII). As a consequence, the primary electron acceptor of PSII, $Q_{A}$, was reduced slowly and was not fully reduced after light-chilling for 6 h in GH. Although the amplitude was small, the development of NPQ was also faster in GH, indicating a higher capacity for non-photochemical energy dissipation. The relative fraction of a fast relaxing component of NPQ (qf) was higher in GH. After light-chilling for 5 h, the values of qf in BB and GR became much smaller than that in GH, indicating BB and GR suffered more significant uncoupling of ATPase and/or irreversible damages in PSII. When fluorescence induction transients were recorded after chilling, significant differences in quenching coefficients (qQ and qN) were observed among the three cultivars.

• 한국환경농학회지
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• 제39권3호
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• pp.273-279
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• 2020

BACKGROUND: After transplanting, the recent abnormal low temperature caused physiological disorders of pepper seedlings. This study was conducted to evaluate the effects of UV-A LED, a physical elicitor, on the chilling tolerance of pepper seedlings. METHODS AND RESULTS: Seedlings were continuously irradiated with 370 and 385 nm UV-A LEDs with 30 W·m^-2 for 6 d. After that, seedlings were exposed to 4℃ for 6 h and then recovered under the normal growing condition for 2 d. There were no significant differences in growth characteristics of UV-A treatments compared to the control. Fv/Fm values of two UV-A treatments were below 0.8. Electrolyte leakage in the control was increased by chilling stress, while 385 nm UV-A had the significantly lowest value. Total phenolic content and antioxidant capacity of two UV-A treatments significantly increased due to UV-A radiation. However, total phenolic content and antioxidant capacity of the control increased due to chilling stress and tended to decrease again during the recovery time. CONCLUSION: We confirmed that UV-A light was effective to induce the chilling tolerance of pepper seedling, and the supplemental radiation of 385 nm UV-A LED before transplanting could be used as a cultivation technique to produce high quality pepper seedlings.

• 한국가금학회지
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• 제41권3호
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• pp.159-164
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• 2014

본 실험은 닭고기 가공 공장별로 침지냉각에 따른 닭 도체의 수분 흡수율 및 감소율 그리고 신선도를 측정 비교하여 품질의 균일화 제고를 위하여 실시하였다. A도계장과 B도계장 닭고기 가공 공장에서 1회 각 40수씩 3회에 걸쳐 총 240수에 대하여 수분 흡수율 및 신선도를 측정하였으며, 수분 흡수율 실험이 완료된 도체에 대하여 개체 포장, 운송하여 실험실 냉장고($4{\pm}1^{\circ}C$)에 입고 후, 저장일별 수분 감소율 및 신선도를 측정하였다. 실험 결과, 수분 흡수율은 A도계장 4.8%, B도계장 4.2%로서 유의적인 차이는 발견되지 않았다. B도계장 실험 도체의 신선도가 냉각 전후 모두, A도계장 실험 도체보다 신선도가 유의적으로 높게 조사되었다. 저장일별 수분 감소율은 A도계장 실험 도체와 B도계장 실험 도체 사이에 유의적인 차이는 나타나지 않았다. 저장일별 신선도는 A도계장 실험 도체가 B도계장 실험 도체에 비해 낮게 조사되었다. 결론적으로 수분 흡수율은 chiller의 길이나 침지시간에 크게 영향을 받지 않으나, 수분 감소율은 침지 시간, 수온 및 심부 온도의 영향을 받는 것으로 예측되었다.

• 한국환경농학회지
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• 제20권2호
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• pp.93-98
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• 2001

저온에 내성인 자포니카의 일품벼와 감수성인 인디카의 태백벼 품종간에 저온처리기간 동안 및 저온처리 후 회복동안에 나타날 수 있는 생리적 반응을 비교하였다. $5^{\circ}C$의 저온처리 3일 동안에 잎의 생체중 및 엽록소 함량은 두 품종간에 차이가 적거나 없었으나 저온처리 후 $25^{\circ}C$에 회복시킨 동안에는 태백벼에 비해 일품 벼가 더 빨리 회복되었다. 상대적 수분함량, 지질과산화 작용의 지표인 malondialdehyde 생성량 및 엽록소 형광은 저온처리기간 동안 및 저온처리 후 회복기간동안에도 두 품종간에 유의적인 차이를 보였고, 이들 생리적 지표들은 생체중 및 엽록소 함량보다는 더 민감한 생리적 지표이었다. 두 품종간에 상대적 수분함량, malondialdehyde 생성량 및 엽록소 형광의 차이는 저온처리 후 회복기간동안보다는 저온처리동안에서 더 적었다. 따라서 이들 결과를 통해서 볼 때 상대적 수분함량, malondialdehyde 생성량과 엽록소 형광은 저온에 내성을 선발하는데 중요한 생리적 지표로 이용할 수 있으리라 생각한다.

• Asian-Australasian Journal of Animal Sciences
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• 제20권2호
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• pp.257-262
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• 2007

The current study was conducted to investigate the optimum stunning voltage and chilling regime with emphasis on reduction in pale, soft and exudative (PSE) pork. The experiments were conducted at seven Korean major pig abattoirs using a total of 91,082 industrial population. Frequencies of PSE meat was found to be significantly (p<0.05) increased as stunning voltage was elevated from 220-240 (13.14%), 250-280 (29.32%) to 430 volts (36.74%). Chilling methods after slaughter, either with cold water showing or rapid chilling reduced PSE meat by 22% compared to a classic chiller-based slow chilling regime. The current study also revealed that chiller temperature during the first 90 minutes had a significant (p<0.001) effect on PSE incidences. Pigs chilled between -5 to $7^{\circ}C$ resulted in the lowest PSE meat (17.8%), followed by higher than $7^{\circ}C$ (21.3%) and lower than $-5^{\circ}C$ (37.5%). The current data implies that low voltage stunning method (eg., 220-240 volts), followed by rapid chilling regime, maintaining chiller temperature between approximately -5 to $7^{\circ}C$ could reduce PSE incidences.

• 생물환경조절학회지
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• 제15권4호
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• pp.390-395
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• 2006

토마토 유묘의 생육에 미치는 glycine betaine의 엽면처리 효과를 분석한 결과, 초장이나 건물중 등의 생육이 대조구인 증류수 처리에 비해 촉진되는 경향을 보였으며 25mM glycine betaine 처리가 가장 좋았다. 저온스트레스 하에서 삼투조절 역할을 하는 가용성 당과 proline의 축적량이 증류수 처리에 비해 glycine betaine처리에서 낮은 경향을 보여 외부에서 엽면 처리한 glycine betaine이 삼투조절 역할을 한 것으로 판단되었으며 이러한 결과는 수용성 단백질과 유리 아미노산의 축적 양상에서도 잘 반영되었다. 이상의 결과로 보아 glycine betaine의 엽면 처리는 저온기 시설 토마토 재배 시 야간 저온장해를 극복할 수 있는 방법으로서 이용 가능성이 있을 것으로 사료된다.

• International Journal of Industrial Entomology and Biomaterials
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• 제20권2호
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• pp.93-98
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• 2010

Bumblebees are widely used to pollinate various crops, especially tomato, in greenhouses and fields. An artificial hibernation is essential for year-round rearing of the bumblebee, which passes through one generation per year. Here, we investigated whether a chilling temperature and humidity affect artificial hibernation of the bumblebee queen Bombus terrestris. In chilling temperature regimes of $0^{\circ}C$, $2.5^{\circ}C$, $5^{\circ}C$, $7.5^{\circ}C$ or $12.5^{\circ}C$ under constant humidity >70%, the queens stored at $2.5^{\circ}C$ exhibited the highest rate of survival, which was 74.0% at one month, 67.0% at two months, 60.0% at three months, 46.0% at 4 months, 33.0% at 5 months, and 24.0% at 6 months. Rates of survival decreased at the following temperatures: $0^{\circ}C$, $5^{\circ}C$, $7.5^{\circ}C$ and $12.5^{\circ}C$. Colony developmental characteristics after diapause were 1.2- to 1.5-fold higher than those of queens stored at $5^{\circ}C$. In terms of chilling humidity, the queens hibernated at 70% under $2.5^{\circ}C$ exhibited the highest rate of survival, which was $93.3{\pm}3.4%$ at one month, $83.3{\pm}0.0%$ at two months, $76.7{\pm}0.0%$ at 3 months and $36.7{\pm}12.1%$ at 5 months. The rates of oviposition, colony foundation and progeny-queen production of queens hibernated at 70% were 80.8%, 30.8% and 30.8%, respectively. These values correspond to 1.7- to 3.3-fold increases in comparison to queens stored at 50% humidity. Therefore, $2.5^{\circ}C$ and 70% R.H. were the favorable chilling temperature and humidity conditions for diapause break of B. terrestris queens.

• 한국동물위생학회지
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• 제20권2호
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• pp.169-175
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• 1997

This study was carried out to assess the effect of the chlorine treatment into water for processing chicken products in each stage of slaughtering, with a special viewpoint related with reducing the viable number of microorganisms by which the water and the chicken body were contaminated. The mean bacterial number on chicken samples after picking process was log5.37$\pm$0.20~5.84$\pm$0.160CFU/$\textrm{cm}^2$. When assessed by standard plate count method, it was the higher one than any other processing stage in which eviscerating, pinning, packaging, and chilling was followed in order of the mean bacterial number. The coliform bacterial numbers on carcasses after sampling from different processing stages were log2.11$\pm$0.63~2.88$\pm$0.25MPN/$\textrm{cm}^2, which show almost similar numbers in each processing stage. But, after chilling process the number was decreased slightly. The bacterial counts in the water for scalding and chilling showed log3.43 $\pm$ 0.59~5.06$\pm$0.21 and log4.30$\pm$0.21~6.62$\pm$0.33CFU/$m\ell$, respectively. In the coliform counts for the water taken out from the 2nd chilling tank, the number was log1.97$\pm$0.35~2.91$\pm$0.22MPN/$m\ell$ which showed higher than those of the 1st and the 3rd chilling tank water. The effect of chlorination in reducing the bacterial numbers was accepted at the residual chlorine concentration of 1$m\ell$/$\ell$by showing the reduction from $10^8$ to $10^4$CFU level and the numbers were decreased less than 10CFU at the concentration of 5mg/$\ell$, when assessed by viable cell counts. In conclusion, these results suggested that chlorination In chilling water with final concentration of 5mg/$\ell$was strongly recommended to reduce the bacterial numbers on final chicken products.

• 한국추진공학회지
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• 제23권3호
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• pp.119-126
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• 2019

극저온 액체산소나 액체수소를 사용하는 액체로켓 엔진은 냉각이 충분하지 않을 경우 펌프 인입부에서 의 케비테이션과 연소기 메니폴드부에서의 급격한 기화에 의한 서지 현상이 발생할 수 있다. 극저온 추진제 사용을 위한 냉각은 유로의 충전을 위한 냉각/충전단계와 충전 후 온도유지 단계로 구분된다. 발사체의 위성투입 능력 향상을 위해서는 상단엔진의 다점화 기능이 필요하며 다점화를 위해서는 무추력 구간 중 다음 시동을 위한 냉각이 수행되어야 한다. 본 연구에서는 지상에서의 엔진의 냉각/충전 및 온도유지, 그리고 상단 엔진이 1차 점화하기 위한 냉각과 무추력 구간에서의 냉각유지, 그리고 다점화를 위한 냉각에 대해 논의한다.

• Journal of Ginseng Research
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• 제25권4호
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• pp.167-170
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• 2001

개갑 인삼종자의 생리적 휴면타파를 위한 적정 저온감응기간을 조사하였다. 채종하여 3개월간 모래로 층적저장하여 개갑이 완료된 종자의 배는 배유의 1/2정도의 크기를 보였다. 인삼종자는 채종 당시의 미숙한 배가 형태적으로 거의 완전한 발달을 보이기까지는 6개월 정도가 소요되었으며, 배의 신장의 실외보다는 실내에 저장하였던 종자가 더 빨리 자랐다. 배 신장이 완료된 종자라 할지라도 60일 이하의 저온처리된 종자는 발아가 되지 않았으며, 발아에 필요한 저온감응기간은 실외의 자연상태에서는 75일 정도이며, 냉장온도(4$^{\circ}C$)에서는 90일 정도가 적정하였다. 그러나 적정의 저온감응을 받은 종자라 할지라도 상온데 지속적으로 방치하게 되면 그 효과는 현저히 감소되었다.