• Ocean and Polar Research
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• 제37권3호
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• pp.201-209
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• 2015

To examine the effects of increased $CO_2$ concentration and seawater temperature on the photosynthesis and growth of forest forming Ecklonia cava (Laminariales, Phaeophyta), sporophytic discs and gametophytes were cultured under three $pCO_2$ concentrations (380, 750, 1000 ppm), four temperatures (5, 10, 15, $20^{\circ}C$ for sporophytes; 10, 15, 20, $25^{\circ}C$ for gametophytes), and two irradiance levels (40, $80{\mu}mol$ photons $m^{-2}s^{-1}$) for 5 days. Photosynthetic parameter values ($ETR_{max}$, $E_k$, and ${\alpha}$) were generally higher as sporophytic discs were grown under low temperature and increased $CO_2$ concentration at 750 ppm. However, photosynthesis of Ecklonia sporophytes was severely inhibited under a combination of high temperature ($20^{\circ}C$) and 1000 ppm $CO_2$ concentration at the two photon irradiance levels. The growth of gametophytes was maximal at the combination of 380 ppm (present seawater $CO_2$ concentration) and $25^{\circ}C$. Minimal growth of gametophytes occurred at enriched $pCO_2$ concentration levels (750, 1000 ppm) and high temperature of $25^{\circ}C$. The present results imply that climate change which is increasing seawater temperature and $pCO_2$ concentration might diminish Ecklonia cava kelp beds because of a reduction in recruitments caused by the growth inhibition of gametophytes at high $pCO_2$ concentration. In addition, the effects of increased temperature and $pCO_2$ concentration were different between generations - revealing an enhancement in the photosynthesis of sporophytes and a reduction in the growth of gametophytes.

• 한국환경농학회지
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• 제38권4호
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• pp.296-306
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• 2019

온도는 곤충의 발달, 성장, 생식에 중요한 요인이며, 또한 곤충의 생존에 직접적 관련있는 물리적 요인이다. 변온동물인 곤충은 생존을 위해 기후변화에 반응을 해야 하며, 저온과 같은 취약한 환경하에서도 다양한 생존전략을 발달시켜야 한다. 본 연구는 저온에 대한 적응에 기여하는 유전자를 동정하기 위해 배추좀나방 유충의 지방체를 저온과 상온에 노출시켜 전사체 분석을 수행하였다. 저온전사체에서는 chitinase, 표피단백질, Hsp23, chytochrome, Glutathione S transferase, phospholipase 2 유전자의 발현이 증가된 반면, 에너지 대사에 관여하는 UDP-당전이효소, trehalase, trehalose transporter는 오히려 발현이 감소하였다. 저온에 곤충이 노출되었을 때, 대사중심인 지방체의 유전자 발현의 변화가 곤충의 온도 적응을 이해하는 단서를 제공할 수 있을 것으로 기대된다.

• 한국농림기상학회:학술대회논문집
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• 한국농림기상학회 2011년도 학술발표회
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• pp.16-18
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• 2011

Evaluation of climate change on the rice productivity was conducted using crop growth simulation model, where Odae, Hwaseong, Ilpum were used as a representative cultivar of early, medium, and medium-late rice maturity type, respectively, and climate change scenario 'A1B' was applied to weather data for future climate change at 57sites. When cropping season was fixed, rice yield decreased by 4~35% as climate change which was caused by poor filled grain ratio with high temperature and low irradiation during grain-filling. When cropping season was changed, rice yield decreased by only 0~5% as climate change which was caused poor filled grain ratio with low irradiation during grain-filling period. However, this irradiation decline was less than when cropping season was fixed. Therefore, we need to develop rice cultivars resistant to low irradiation which can maintain high filled grain ratio under poor irradiation condition, and late maturity rice cultivars whose growing period is longer than the present medium-late maturity type.

• 한국결정성장학회지
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• 제28권5호
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• pp.179-184
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• 2018

고효율 태양전지용 단결정 실리콘 웨이퍼는 쵸크랄스키 성장법으로 석영도가니 속의 실리콘 액체에서 단결정 잉곳을 성장시켜 제조된다. 석영도가니 성분 중의 하나는 산소는 실리콘 잉곳으로 유입되고, 태양전지의 전력변환 효율 저하 문제를 발생시킨다. 이러한 산소 유입을 줄이는 다양한 방법 중 하나는 히터의 모양과 구조를 변경하는 방법이 있다. 그러나 히터 구조 변경 시 단결정 실리콘 잉곳 바디 성장에 필요한 온도 분포경향에 큰 변화를 일으킨다. 따라서 본 연구에서는 쵸크랄스키 실리콘 성장에서 다양한 히터의 구조와, 히터와 석영도가니의 상대적 위치가 단결정 실리콘 잉곳 Body 성장 시의 ATC 온도와 Power 분포경향에 미치는 영향에 대하여 연구하였다. 삼중점과 히터 중심과의 위치가 가장 먼 SSH-Low가 가장 높은 ATC 온도 분포경향을 보여주었다. 또한 길이가 짧은 Short Side Heater(SSH-Up, SSH-Low)보다는 실리콘 액체를 담고 있는 석영도가니 측면의 많은 영역을 커버할 수 있는 일반 Side Heater(SH)가 가장 Power 소모 측면에서 유리하였다. 특히 본 연구 결과를 통해 고효율 태양전지용 단결정 실리콘 잉곳 성장 시 필요한 효율적인 ATC 온도를 예측할 수 있음을 확인하였다.

• 한국연초학회지
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• 제4권1호
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• pp.43-49
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• 1982

This experiment was carried out to study the influence of temperature on the growth rate and nutrient uptake of tobacco seedlings grown on neutralized charcoal bed during temporary transplanting. The highest growth rate was obtained at tile temperature of 26-22-$l8^{\circ}C$, probably due to fast establishment of roots in the soil. Seedling growth was better in neutralized charcoal bed than in chaffy charcoal bed at each temperature. Days required for fresh weight to reach 20g/10p1ants were shortened by 9~12days as the temperature increased from 18-14-$l0^{\circ}C$ to 26-22-$l8^{\circ}C$. Compared with chaffy charcoal bed, days required for fresh weight to reach 20g/10 plants with neutralized charcoal bed were shortened by about 5 days, 4 days, and 2days at 18-14-$l0^{\circ}C$, 22-18-$l4^{\circ}C$, and 26-22-$l8^{\circ}C$, respectively. Three macronutrient (N, $P_2O_5,\;K_2O$) contents in seedlings increased with increase of temperature. At each temperature, N and $K_2O$ contents in seedlings of neutralized charcoal bed was higher than those of chaffy charcoal bed, whereas that of $P_2O_5$ was low conversely. Nitrate nitrogen from nitric acid that was used to neutralize chaffy charcoal was maintained to tile end of seedling period, providing the source of nitrate nitrogen for the better seedlings.

• Applied Biological Chemistry
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• 제50권1호
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• pp.6-11
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• 2007

P. freudenreichii KCCM 31227을 whey 배지에서 배양시 whey 배지의 살균방법 즉, 고압증기멸균(121$^{\circ}C$, 15분), 저온살균(60$^{\circ}C$, 30분) 방법과 배양액에 yeast extract를 0.5, 1% 첨가하였을 때 생균수와 총산도를 측정하여 P. freudenreichii KCCM 31227의 생육특성을 조사하였다. 6% whey 배지보다는 12% whey 배지에서, yeast extract 0.5% 보다는 1.0% 첨가 시 생균수가 높았고, 12% whey 배지에 yeast extract를 1.0% 첨가하고 저온살균하였을 때 배양 72시간에 7.5${\times}10^7$ cfu/ml로 가장 높은 생균수를 나타냈다. 총산도는 12% whey 배지에 yeast extract를 1.0% 첨가하여 저온살균하였을 때 5.2로 가장 높았다. 배양 72시간 동안 생균수와 총산도의 증가는 유사한 경향을 보여주었다. Propionic acid와 acetic acid의 생성은 고온살균보다 저온살균에서 높게 검출되었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.537-538
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• 2006

BSCCO thin films have been fabricated by epitaxy growth at an ultra-low growth rate. The growth rates of the films was set in the region from 0.17 to 0.27 nm/min. MgO(100) was used as a substrate. In order to appreciate stable existing region of Bi 2212 phase with temperature and ozone pressure, the substrate temperature was varied between 650 and $720^{\circ}C$ and the highly condensed ozone gas pressure ($PO_3$) in vacuum chamber was varied between $2.0{\times}10^{-6}$ and $2.3{\times}10^{-5}\;Torr$.

• 한국전기전자재료학회논문지
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• 제19권4호
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• pp.344-349
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• 2006

A sublimation epitaxial method, referred to as the Closed Space Technique (CST) was adopted to produce thick SiC epitaxial layers for power device applications. We aimed to systematically investigate the dependence of SiC epilayer quality and growth rate during the sublimation growth using the CST method on various process parameters such as the growth temperature and working pressure. The etched surface of a SiC epitaxial layer grown with low growth rate $(30{\mu}m/h)$ exhibited low etch pit density (EPD) of ${\sim}2000/cm^2$ and a low micropipe density (MPD) of $2/cm^2$. The etched surface of a SiC epitaxial layer grown with high growth rate (above $100{\mu}m/h$) contained a high EPD of ${\sim}3500/cm^2$ and a high MPD of ${\sim}500/cm^2$, which indicates that high growth rate aids the formation of dislocations and micropipes in the epitaxial layer. We also investigated the Schottky barrier diode (SBD) characteristics including a carrier density and depletion layer for Ni/SiC structure and finally proposed a MESFET device fabricated by using selective epilayer process.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 추계학술발표강연 및 논문개요집
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• pp.21-21
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• 2003

To increase the light-emission efficiency of LED, we increased the internal and external quantum efficiency by suppressing the defect formation in the quantum well and by increasing the light extraction efficiency in LED, respectively. First, the internal quantum efficiency was improved by investigating the effect of a low temperature (LT) grown p-GaN layer on the In$\sub$0.25/GaN/GaN MQW in green LED. The properties of p-GaN was optimized at a low growth temperature of 900oC. A green LED using the optimized LT p-type GaN clearly showed the elimination of blue-shift which is originated by the MQW damage due to the high temperature growth process. This result was attributed to the suppression of indium inter-diffusion in MQW layer as evidenced by XRD and HR-TEM analysis. Secondly, we improved the light-extraction efficiency of LED. In spite of high internal quantum efficiency of GaN-based LED, the external quantum efficiency is still low due to the total internal reflection of the light at the semiconductor-air interface. To improve the probability of escaping the photons outside from the LED structure, we fabricated nano-sized cavities on a p-GaN surface utilizing Pt self-assembled metal clusters as an etch mask. Electroluminescence measurement showed that the relative optical output power was increased up to 80% compared to that of LED without nano-sized cavities. I-V measurement also showed that the electrical performance was improved. The enhanced LED performance was attributed to the enhancement of light escaping probability and the decrease of resistance due to the increase in contact area.

• Journal of Electrochemical Science and Technology
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• 제9권2호
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• pp.118-125
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• 2018

Herein we report on the selective synthesis and direct growth of nanostructures using an aqueous chemical growth route. Specifically, Al-doped ZnO (AZO) nanoflakes (NFs) are vertically grown on indium tin oxide (ITO) coated flexible polyethylene terephthalate (PET) sheets at low temperature and ambient environment. The morphological, optical, and electrical properties of the NFs are investigated as a function of the Al content. Furthermore, these AZO-NFs are integrated into perovskite solar devices as the electron transport layer (ETL) and the fabricated devices are tested for photovoltaic performance. It was determined that the doping of AZO-NFs significantly increases the performance metrics of the solar cells, mainly by increasing the short-circuit current of the devices. The observed enhancement is primarily attributed to the improved conductivity of the doped AZO-NF, which facilitates charge separation and reduces recombination. Further, our flexible solar cells fabricated through this low temperature process demonstrate an acceptable reproducibility and stability when exposed to a mechanical bending test.