• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 춘계학술발표강연 및 논문개요집
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• pp.44-44
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• 2003

Growth mechanism of carbon nanotubes(CNTs) synthesized by chemical vapor deposition is abided by two growth modes. These growth modes are classified by the position of activated catalytic metal particle in the CNTs. Growth mode can be also affected by interaction between substrate and catalytic metal and induced energy such as thermal and plasma. We studied the reaction of catalytic metal to the substrate and growth mode of CNTs. Various substrates such as Si(100), graphite plate, coming glass, sapphire and AAO membrane are used to study the relation between catalytic metal and substrate in the synthesis of CNTs. For catalytic metal, thin film was deposited on various substrate via sputtering technique with a thickness of ∼20nm and magnetic fluids with none-sized particles were dispersed on AAO membrane. After laying process on AAO membrane, it was dried at 80$^{\circ}C$ for 8 hour. Synthesizing of CNTs was carried out at 900$^{\circ}C$ in NH3/C2H2 mixture gases flow for 10minutes.

• 유통과학연구
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• 제21권1호
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• pp.23-31
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• 2023

Purpose: this study is aimed at assessing the contribution of education and innovation to the economic growth of Kazakhstan, the correlation between them is checked based on two levels on a national scale and a regional scale. Based on the literature review, it was revealed that in the vastness of the scientific community, there are many views concerning the influence of educational and innovative factors on economic growth. Research design, data and methodology: the research methodology is divided into two levels, at the first level, a correlation analysis is carried out between key factors and the economic growth of the country (GDP), at the second level, the same factors are analyzed, but the impact on the economic growth of the region (GRP) is estimated. Statistical data on educational and innovation potential is taken from the Bureau of National Statistics for the period 2003-2021. Results: in this study, it was revealed that the economic development of regions could be influenced by such indicators that cannot affect the entire state in aggregate and vice versa. In addition, the correlation analysis results showed that investments in innovations affect economic growth at the country and the regional level. Conclusions: based on the results of the assessment of educational and innovative potential, policy recommendations and further research in this area were proposed.

• Journal of Forest and Environmental Science
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• 제39권4호
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• pp.195-202
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• 2023

In this study, we sought to compare and evaluate the accuracy and predictive performance of machine learning algorithms for estimating the growth of individual Larix kaempferi trees in Gangwon Province, Korea. We employed linear regression, random forest, XGBoost, and LightGBM algorithms to predict tree growth using monitoring data organized based on different thinning intensities. Furthermore, we compared and evaluated the goodness-of-fit of these models using metrics such as the coefficient of determination (R²), mean absolute error (MAE), and root mean square error (RMSE). The results revealed that XGBoost provided the highest goodness-of-fit, with an R² value of 0.62 across all thinning intensities, while also yielding the lowest values for MAE and RMSE, thereby indicating the best model fit. When predicting the growth volume of individual trees after 3 years using the XGBoost model, the agreement was exceptionally high, reaching approximately 97% for all stand sites in accordance with the different thinning intensities. Notably, in non-thinned plots, the predicted volumes were approximately 2.1 m³ lower than the actual volumes; however, the agreement remained highly accurate at approximately 99.5%. These findings will contribute to the development of growth prediction models for individual trees using machine learning algorithms.

• 한국환경과학회지
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• 제33권6호
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• pp.355-365
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• 2024

This study was conducted to investigate the effects of CO₂ supplement on growth and quality in greenhouse lettuce cultivation. When CO₂ was supplied at 1,500 ppm in lettuce cultivation, overall growth parameters such as number of leaves, leaf area, plant length, fresh weight, and dry weight were superior compared to those of the control group. While there was no significant difference in relative growth rate due to CO₂ supplement, an increase in leaf area index was observed with CO₂ usage. Furthermore, although there was no significant difference in the content of water-soluble vitamins such as Vitamin C, B1, B2, B5, and B6 due to CO₂ supplement, the Vitamin B3 content in the CO₂ treatment group was 0.5 mg/kg higher than in the control group. Therefore, the use of CO₂ in lettuce cultivation resulted in increased yield and promoted growth, enabling early harvesting.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2002년도 봄 학술발표대회 발표논문집
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• pp.465-467
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• 2002

The effects of salicylic acid (SA) on growth and proline were investigated in cucumber seedlings. Exogenous application of SA(100 uM - 1mM) led to a noticeable decrease in root and shoot growth, and dry weights of seedlings. Anatomical observation on leaf anatomy of cucumber revealed that the thickness of all leaf tissue components decreased in SA-treated plants. The effect was most promounced on the width of the adaxial epidermis. In the separate and simultaneous effects of SA and water deficit induced by PEG on growth and proline accumulation, the water deficit treatments had greater effects on growth traits and proline content than SA. Combinations of SA and PEG decreased dry matter and root length, and resulted in higher proline in both shoots and roots than SA stress alone. Shoots had higher proline than roots.

• Plant Resources
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• 제7권2호
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• pp.155-158
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• 2004

Activate charcoal (AC) can be utilized as a soil conditioner in agricultural crop areas. This study was conducted to investigate the effect of AC on growth and yield of Zingiber mioga ROSC as affected by different amounts of AC. The results obtained are summarized as follows. Growth characteristics including plant height and leaf length were the highest when activated charcoal added with 10-30%, suggesting that optimum amount of activated charcoal was ranged from 10 to 30%. Growth and enlargement of the root were improved by 10% AC with higher rhizome length and weight.

• 한국작물학회지
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• 제44권3호
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• pp.282-287
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• 1999

The object of this study was to determine the difference of the time course changes of transpiration, diffusion resistance and photosynthetic rate of rice at several different growth stages subjected to soil moisture stress (SMS) and recovery by irrigation. A japonica rice cultivar 'Dongjinbyeo', was grown under flooded condition in a plastic container filled with silty loam soil. At 5 main growth stages, the container was treated by SMS until initial wilting point (IWP) and then reirrigated. The duration of SMS until IWP were the longest, 13 days for tillering stage, and the shortest, 7 days for panicle initiation and meiosis stage. The transpiration rate rapidly decreased during SMS and the transpiration rate at IWP of the stressed plant showed 10∼20% compared with control, and the transpiration rate of stressed plant at most growth stages also recovered rapidly after irrigation and then reached 100% of control within a week. The shoot photosynthetic rate in all growth stages rapidly decreased by SMS, and the rates at IWP of stressed plants were de-creased nearly to 0%, beside the treatment at tillering stage. The recovery degree of photosynthetic rate by irrigation ranged from 20 to 90%, showed higher at early growth stages of SMS treatment than that of later stages. At all growth stages the leaf diffusion resistance of stressed plants was over 3 times that of the control resulting from a rapid increase at 3 to 5 days after draining for SMS, and showed quick recovery by irrigation within 3 days after drainage. The above physiological parameters changed in close relation with the decrease of the soil matric potential after SMS. These results indicate that at all main growth stages of rice plants the transpiration and photosynthesis reduction by stomatal closure reponded sensitively to the first stage of SMS closely related with decrease of soil water potential, while those recovery pattern and recovered degree by irrigation are little different by growth stage of rice.

• 한국환경복원기술학회지
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• 제19권1호
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• pp.13-23
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• 2016

This study was conducted to investigate the growth characteristics of warm-season turfgrasses and to find out suitable turfgrass species on Saemangeum reclaimed land. Twenty native zoysiagrass(Zoysia sinica, Z. matrella, Z. japonica, Medium-leaf type zoysiagrass(hybrid zoysiagrass)) and bermudagrass(Cynodon dactylon) collected from Korea were used in this study. Total stolon length and the number of stolon per square meter, relative growth rate of shoot and stolon, and coverage rate were analyzed for 2 year. C. dactylon showed not only the most growth response with high relative growth rate of shoot and stolon, which were 19.9% and 66.3%, but also resulted in higher level of turf visual quality compared to others. Whereas Z. japonica showed the least growth response with low relative growth rate of shoot and stolon, which were 2.4% and 0.7%. Although all warm-season turfgrasses took root and grew up well, there were different growth rates between the interspecies. Z. sinica 'Z2034', Z. matrella 'Z4091', Z. japonica 'Z1064', Medium-leaf type zoysiagrass 'ZN6019' and C. dactylon 'BN7014' were the greatest growth rate of shoot and stolon. These results will be useful for selecting salt tolerant breeding lines and also used to develop a turfgrass cultivar with strong salinity tolerance through continuous monitoring.

• Biotechnology and Bioprocess Engineering:BBE
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• 제3권2호
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• pp.51-54
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• 1998

It has been proved that co-cultivation of human neroblastoma cells and human fibroblast cells can enhance nerve cell growth and the production of BDNF in perfusion cultivation. In batch co-cultivation, maximum cell density was increased up to 1.76${\times}$106 viable cells/mL from 9${\times}$105 viable cells/mL of only neuroblastoma cell culture. The growth of neuroblastoma cells was greatly improved by culturing both nerve and fibroblast cells in a perfusion process, maintaining 1.5${\times}$106 viable cells/mL, which was much higher than that form fed-batch cultivation. The nerve cell growth was greatly enhance in both fed-batch and perfusion cultivations while the growth of fibroblast cells was not. It strongly implies that the factors secreted from human fibrobast cells and/or the environments of co-culture system can enhance both cell growth and BDNF secretion. Specific BDNF production rate was not enhanced in co-cultures; however, the production period was increased as the cell growth was lengthened in the co-culture case. Competitive growth between nerve cells and fibroblast cells was not observed in all cases, showing no changes of fibroblast cell growth and only enhancement of the neuroblastoma cell growth and overall BDNF production. It was also found that the perfusion cultivation was the most appropriate process for cultivating two cell lines simultaneously in a bioreactor.

• 생물환경조절학회지
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• 제29권2호
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• pp.181-188
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• 2020

본 연구는 국내 특산식물이며 관상소재로 개발이 가능한 산꼬리풀의 효과적인 육묘조건을 구명하기 위해 수행되었다. 육묘는 토양 종류와 비료 농도, 차광정도, 추비 농도, 종자의 광원 전처리 및 채종 시기별로 각 요인을 달리하여 수행하였다. 연구 결과, 산꼬리풀은 원예상토에서 생육이 우수하였으며, 혼용토에서는 비료 첨가 시 생육이 억제되었다. 차광은 55% 차광조건에서 무차광에 비해 전체적인 생육이 향상되었다. 고농도(1000mg·L^-1)의 Hyponex는 육묘 시 생육을 촉진하였으며, 파종 전 종자에 대한 적색광 조사는 추후 초장과 생체중 향상에 효과적이었다. 채종 시기는 2018년도 종자가 2017년 종자보다 생육이 우수하였다.