• Journal of Biosystems Engineering
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• 제17권1호
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• pp.55-64
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• 1992

The aim of this study was to develop a phytotron for studying the effects of environmental factors such as temperature and humidity on plant growth. This equipment consists of the growth chamber, and the measurement and control system including control algorithms required for optimum operation. As the first step of the study, a temperature and humidity control system was developed. The results of this study are summarized as follows ; 1. Pt-100 was selected to measure temperature and a linearized op-amp circuit was developed for signal conditioning. 2. Pt-100 wet bulb thermometer based on Asmann's principle was developed to measure relative humidity. 3. Temperature and relative humidity conditions were controlled by ON-OFF and PWM operation using a PID controller. And an autotuning algorithm using the characteristics of step response was developed to determine optimal PID constants which were independent of the size of apparatus and environmental factors. 4. Under the ambient temperature of $20^{\circ}C{\sim}25^{\circ}C$, the temperature was kept within the error of ${\pm}0.3^{\circ}C$ in the range of $10^{\circ}C{\sim}40^{\circ}C$, and the relative humidity was kept within the error of ${\pm}5%$ in the range of ${\pm}50%{\sim}90%$.

• 한국결정성장학회지
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• 제30권3호
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• pp.117-122
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• 2020

In last few decades, although thermal and/or solutal buoyancy-driven recirculating flows in a closed ampoule have been intensively studies as a model problem, there exist interesting total molar flux of Hg₂Br₂ that have been unreported in the literature. It is concluded that the total molar flux of Hg₂Br₂(A) increases linearly and directly as the temperature difference regions in the range of 10℃ ≤ ΔT ≤ 50°, 3.5 × 10³ ≤ Gr_t ≤ 4.08 × 10³, 4.94 × 10⁴ ≤ Gr_s ≤ 6.87 × 10⁴. For the range of 10 Torr ≤ P_B ≤ 150 Torr, the total molar flux of Hg₂Br₂(A) decays second order exponentially as the partial pressure of component B (argon as an impurity), P_B increases. From the view point of energy transport, the fewer the partial pressure of component B (argon), P_B is, the more the energy transport is achieved.

• Bulletin of the Korean Chemical Society
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• 제31권12호
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• pp.3579-3582
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• 2010

We studied the reaction of tri-methylaluminum (TMA) on hydroxyl (OH)-terminated Si (001) surfaces for the initial growth of aluminum oxide thin-films using density functional theory. TMA was adsorbed on the oxygen atom of OH due to the oxygen atom’s lone pair electrons. The adsorbed TMA reacted with the hydrogen atom of OH to produce a di-methylaluminum group (DMA) and methane with an energy barrier of 0.50 eV. Low energy barriers in the range of 0 - 0.11 eV were required for DMA migration to the inter-dimer, intra-dimer, and inter-row sites on the surface. A unimethylaluminum group (UMA) was generated at each site with low energy barriers in the range of 0.21 - 0.25 eV. Among the three sites, the inter-dimer site was the most probable for UMA formation.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권6호
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• pp.553-556
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• 2006

A cis-1,2-dichloroethylene (cis-DCE)-degrading anaerobic bacterium, Clostridium sp. strain KYT-1, was isolated from a sediment sample collected from a landfill site in Nanji-do, Seoul, Korea. The KYT-1 strain is a gram-positive, endospore-forming, motile, rod-shaped anaerobic bacterium, of approximately $2.5{\sim}3.0\;{\mu}m$ in length. The degradation of cis-DCE is closely related with the growth of the KYT-1 strain, and it was stopped when the growth of the KYT-1 strain became constant. Although the pathway of cis-DCE degradation by strain KYT-1 remains to be further elucidated, no accumulation of the harmful intermediate, vinyl chloride (VC), was observed during anaerobic cis-DCE degradation. Strain KYT-1 proved able to degrade a variety of volatile organic compounds, including VC, isomers of DCE (1,1-dichloroethylene, trans-1,2-dichloroethylene, and cis-DCE), trichloroethylene, tetrachloroethylene, 1,2-dichloroethane, 1,1,1-trichloroethane, and 1,1,2-trichloroethane. Strain KYT-1 degraded cis-DCE at a range of temperatures from $15\;to\;37^{\circ}C$, with an optimum at $30^{\circ}C$, and at a pH range of 5.5 to 8.5, with an optimum at 7.0.

• 대한기계학회논문집A
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• 제25권7호
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• pp.1047-1054
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• 2001

Atomic Force Microscope (AFM) was used to study cross sectional profiles and dimensions of fatigue striations in 2017-T351 aluminum alloy. Their widths(SW) and heights (SH, SH(sub)h, SH(sub)ι) were measured from the cross sectional profiles of three-dimension AFM images. The following results that will be helpful to understand the fatigue crack growth mechanism were obtained. (1) The relation of SH=$\alpha$(SW)(sup)1.2 was obtained. (2) The ratio of the striation height to its width SH/SW, SH(sub)h/SW and SH(sub)ι/SW did not depend on the stress intensity factor range ΔK and the stress ratio R( =P(sub)min/P(sub)max = K(sub)min/K(sub)max). (3) Effect of precipitate on the morphology of striation was changed by the relative dimensional difference between the striation width SW and the precipitates. From these results, the applicability of the AFM to nano-fractography is discussed.

• 열처리공학회지
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• 제17권3호
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• pp.139-145
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• 2004

Equal channel angular pressing (ECAP) technique had been adapted to the Mg alloy (AZ31) for achieving effective grain refinement through severe deformation. The average grain size of $2.5{\mu}m$ could be obtained after 4 passes. The stability of the ECAPed structure at elevated temperatures was examined by annealing the ECAPed materials over a wide range of temperature between 473 and 748 K. The average activation energy, Q, for static grain growth of 1, 2 and 3 passes was 33.7 kJ/mole (=0.25QL, activation for lattice diffusion). The abnormally low Q value in the lower temperature range may indicate that grain growth occurs in the unrecrystallized microstructure where non-equilibrium grain boundaries containing a large number of extrinsic dislocations exist. The yield stresses of the ECAPed alloys decreased whereas the elongations increased after the ECAP process. These results should be related to the modification of texture for easier slip on basal plane.

• 한국기후변화학회지
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• 제7권4호
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• pp.493-498
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• 2016

This study was conducted to investigate the effect of environment factors on full bloom stage and fruit width in four peach cultivars. The average temperature in March was the main factor to determine the date of full bloom in 'Kurakatawase'($-0.6871^*$) and 'Changhowon Hwangdo'($-0.5270^*$). The fruit growth curve after 35 days from full bloom was the double sigmoid shape in 'Changhowon Hwangdo' cultivar. Environmental factors affecting fruit width were mean diurnal range(BIO2) and temperature annual range(BIO 7) in 'Kurakatawase', growing degree days(GDD) after 30 days from full bloom and July precipitation in 'Yumyeong', and annual mean temperature(BIO1), BIO7, and July precipitation in 'Kawanakajima Hakuto'. Of these, major environmental factors affecting fruit width in more than two cultivars were BIO7 and July precipitation.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 추계학술발표대회 논문집
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• pp.376-382
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• 2011

Since the Industrial Revolution has caused global change by using of a fossil fuel, a reckless and growth-oriented development. A global mean temperature since 19th century has climbed up 0.4~$0.8^{\circ}C$. Our country, afterwards, global warming has increased the temperature every season. After The Kyoto Protocol regarding a greenhouse gas reduction goal took effect, be situations that decrease of greenhouse gas was acutely required. Therefore, interest of utilization of the new & renewable energy is increasing everyday. In advanced research, we shows that at first divided a country to nine range by natural geography, and second executed Meteorological data analysis of recent 30 years considering level of significance by nine range. The results of advanced research are that the similarities are low because there are the regions that temperature deviation of the similar climate regions is large in winter season, and there are not characteristics of clear discrimination of temperature. This study shows that at first divided a country to six range by temperature range, and second executed Meteorological data analysis of recent 30 years considering level of significance by six range. The results of this study are that in heating load calculation of building, periodic temperature data management is required because facility capacity and cost are affected greatly by outdoor temperature, and temperature by climate range needs consideration of pertinent area. Ground temperature was assumed of the weather in region, the ground and soil. Lastly, we were able to know that establishment of climate region by temperature range can be useful policy making and plans of design of the horticultural facilities and architectures.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.250-250
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• 2017

Studies were conducted to select the optimum sowing date and planting density of sesame in the middle area of Korea. To select the optimum sowing date, sesame seeds sowed from 20 April to 7 July with 15-day intervals. To select the optimum planting density, sesame seeds investigated under four different planting distances ($30{\times}10,\;30{\times}15,\;30{\times}20$, and $30{\times}25cm$)respectively in the experimental field. As seeding date was delayed, days to emergence were shortened flowering and maturing date were delayed. Delayed sowing date resulted in decreased length, capsule setting stem length and number of capsules, and branchs per plant. Number of Capsules was high sowing date on 5 May in the range of 90~95ea/plant in sesame. Also yield of sesame seeds was most high on 5 May in the range of 142kg/10a by sowing date. Sowing date up to 5 May showed no effect on grain yield, but from 5 June to 5 July decreased 27%, 68% and 86%, respectively. For all planting distances, weight of 1,000 grain was not significantly different. However, number of branches and capsules tended to increase. Number of Capsules was high planting distance of $30{\times}20cm$ and $30{\times}25cm$ in the range of 146.7~165.7ea/plant in the Geonbaekkae. Areumkkae also showed the same tendency on planting distance of $30{\times}20cm$ and $30{\times}25cm$ in the range of 122.0~147.5ea/plant, respectively. Yield of Geonbaekkae and Areumkkae seeds was most high 116kg/10a, 117kg/10a, respectively on planting distance $30{\times}20cm$. Decreased in the planting distance of sesame has increased the incidence of disease and lodging. Based on the results, we suggest a planting distance of $30{\times}20cm$ maximal growth and yield of sesame in the middle area of Korea. Considering growth characteristics, sesame yield ability, the optimum sowing date was 5 May and optimum planting pattern was founded to be two rows planting in one ridge and planting densities was $30{\times}20cm$.

• Journal of Ginseng Research
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• 제12권2호
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• pp.158-163
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• 1988

고려인삼의 묘를 GA, 2,4-D 및 B-9로 처리하여 암하에서 생육시켰다. 생장효율($E_1$ = St/Ro, $E_2$ = St/(Ro-Rt), $E_3$ = (Ro- Rt)/ Ro, 여기서 St는 지상부중, Ro와 Rt는 초기와 일정시간 후의 뿌리의 무게임)과 기타 관련된 요인 및 상호관계를 조사하였다. $E_1$과 $E_3$는 온도변화에 이차식 관계를 보인 반면 $E_2$는 부의 직선 상관을 보였다. $E_1$은 $E_2$보다 $E_3$에 더 의존하였다. $E_2$와 $E_3$값은 거의 같았다. $E_2$는 전에 보고된 값보다 커서 뿌리간 큰 차이가 있음을 나타낸다. GA는 고온역에서 $E_2$와 $E_3$값을 증대시켰으며 B-9은 모든 온도에서 $E_3$를 크게 감소시켰고고 저온역에서 $E_2$를 감소시켰다. 지상부중은 대부분의 생장조절제와 온도에서 기질량과 유의정상관을 보였으며 몇경우에는 호흡소모량과 유의정상관을 보였다. 호흡소모량은 저온역에서만 $E_1$ 및 $E_3$와는 유의정상관을 $E_2$와는 유의부상관을 보였다.