• FLOWER RESEARCH JOURNAL
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• 제17권1호
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• pp.29-35
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• 2009

The study was conducted to examine effective concentration and fertilization time of $CO_2$ for the growth of potted Phalaenopsis in growth chambers. Enrichment level of $CO_2$ was 1,000 or $2,000{\mu}mol{\cdot}mol^{-1}$ and fertilization time was 06:00~12:00, 00:00~06:00, or 18:00~24:00. Two, seven, or twelve month-old clonal micropropagules of Phalaenopsis cultivars were cultured for 99 days. Leaf number, leaf length, leaf width, root length and fresh weight of all Phalaenopsis cultivars in $2,000{\mu}mol{\cdot}mol^{-1}$ $CO_2$ were significantly greater than that of $1,000{\mu}mol{\cdot}mol^{-1}\;CO_2$. $CO_2$ fertilization time was the greatest growth in 0:00~06:00.

• Journal of the Korean Crystal Growth and Crystal Technology
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• 제13권5호
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• pp.235-240
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• 2003

The development of large area GaN substrates is one of important issues in expanding of GaN-based applications. In order to investigate the possibility, GaN thick films were grown by a sublimation technique, using MOCVD-GaN films grown on a sapphire as a seed-crystal substrate and a commercial GaN powder as a source material. The pressure in chamber under the fixed flow rate of $N_2$ gas and $NH_3$ gas was kept at 1 atmosphere and the effects of the various processing parameters such as the distance between source material and seed crystal, the temperature of top- and bottom heater and the growth time during the growth of GaN thick film were investigated. The growth feature and microstructure of the GaN thick films were observed by SEM and XRD. The optical bandgap properties and the defects were evaluated by the PL measurement. By these results, the growth conditions such as the distance between the GaN source and the seed substrate, the growth temperature and the growth time were determined for the satisfied growth of GaN thick films.

• Journal of the Korean Crystal Growth and Crystal Technology
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• 제14권2호
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• pp.37-46
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• 2004

The electrochemical adsorption of the Ag ions from aqueous solution on pelletized activated carbon monolith was investigated over wide range of operation time. The adsorption capacities of pelletized activated carbon monolith are associated with their internal porosity and are related properties such as surface area, pore size distribution. The chemical industry generates wastewater that contains toxic matters like heavy metals in small concentrations so that their economic recovery is not feasible. But, the method using activated carbon monolith can be used to withdrawal of heavy metals in waste water. After the electrochemical treatment, the quantitative properties in Ag ion solutions are also examined by pH concentration and studied elemental analysis by ICP-Atomic Emission Spectrometer and Energy Disperse X-ray (EDX) spectra. It is consider that the pH is very important factor at the reason of water pollutant with increasing acidity in industrial field. The result of quantitative analysis using Inductively Coupled Plasma-Atomic Emission Spectrometer of metal after electrochemical reaction in Ag ions solution depending on time are shown that the amount of Ag ions deposited was decreased with growth of Ag particles on the carbon surfaces as increasing electrochemically treated time. And, surface morphologies are investigated by scanning electron microscopy (SEM) to explain the changes in adsorption properties.

• Proceedings of the KSME Conference
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.447-452
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• 2001

An automated system is developed to perform fatigue crack growth tests under constant effective stress intensity factor range ${\Delta}K_{eff}$. In the system, crack length and crack opening load are measured in real-time by using the unloading elastic compliance method. The system consists of two personal computers, an analogue electrical subtraction circuit, a stepping motor, a stepping motor driver, a PIO board, and the application software used to integrate the whole system. The performance of the developed system was tested and discussed performing constant ${\Delta}K_{eff}$ crack growth tests on a CT specimen of 7075-T6 aluminum alloy. The performance of the system is found to be strongly dependent on the accuracy of measurements of crack opening load. Besides constant ${\Delta}K_{eff}$ testing, the system is expected to be successfully applied for automation of various fatigue tests.

• Journal of Aquaculture
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• 제10권2호
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• pp.97-103
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• 1997

Larval growth of the oyster, Crassostrea nippona, was investigated at the different conditions such as water volume, depth of culture vessel and initiative feeding time at $23^{\circ}C$. As a result, morphological changes were occurred during the early larval growth. That is, shell length was higher than shell height at the time of D-shaped larvae. Later, the length became equal to the hight when their shell length reached $127\mum$and then shell height increased rapidly. Some of pediveliger larvae with the size of $360\mum\;in\;shell\;length\;and\;385\mum$ in shell height began to temporarily settle on the substrate after 18 days. The result also indicated that the depth of culture vessel turned out to be an important factor rather than water volume for the larval growth. The fist feeding time of oyster larvae appeared to be the first day after fertilization.

• Korean Journal of Plant Resources
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• 제18권1호
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• pp.194-197
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• 2005

This experiment was conducted to investigate the effect of turf growth characteristics to different transplanting times. It observed that the turf growth was decreased according to delaying the transplanting time. In respect to the turf growth characteristics, it appeared that there was good for transplanting time to transplant the turf seedling before early July. With sustaining the short day length after early July, it shown that number of branch on stolen, number of nodes and Total length of stolen were apparently decreased. Especially, number of branch on stolon was decreased from 2nd up-growing branch.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• 제16권5호
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• pp.441-447
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• 2003

When a SnO$_2$ thin film was deposited by thermal CVD, two different types of growth behavior that were dependent on the deposition temperature were observed. The film grown at 475$^{\circ}C$ had a wide grain size distribution and a faceted surface shape. On the other hand, the film grown at 5$25^{\circ}C$ had a relatively narrow grain size distribution and a rounded sulfate shape. The aspects of grain shape and growth behavior agree well with the theory of gram growth and a roughening transition. The charge tarrier density decreased with deposition time. According to photoluminescence measurements, the peak intensity of the spectra occurred at approximately 2.5 eV, which is related to oxygen vacancies, and decreased with increasing of deposition time. These measurement results suggest that the number of oxygen vacancies, which is related to the electrical conductivity, decrease with deposition time.

• Journal of the Korean Crystal Growth and Crystal Technology
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• 제18권5호
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• pp.191-194
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• 2008

We will focus on the horizontal Bridgman growth system to analyze the transport phenomena numerically, because the simple furnace system and the confined growth environment allow for the precise understanding of the transport phenomena in solidification process. In conventional melt growth process, the dopant concentration tends to vary significantly along the crystal. In this work, we propose the modification of crucible geometry for improving the productivity of silicon single-crystal growth by controlling axial specific resistivity distribution. Numerical analysis has been performed to study the transport phenomena of dopant impurities in conventional and proposed Bridgman silicon growth using the finite element method and implicit Euler time integration. It has been demonstrated using mathematical models and by numerical analysis that proposed method is useful for obtaining crystals with superior uniformity along the growth direction at a lower cost than can be obtained by the conventional melt growth process.

• Asia-Pacific Journal of Business
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• 제7권1호
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• pp.1-10
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• 2016

This study attempts to investigate the effects of different types of debts on economic growth in Bangladesh using time series data spanning from 2000 to 2015. In this study, the RDL model has been applied to determine the long run relationship among the selected variables. The result of the ARDL model shows that there exists a long term relationship between economic growth and the debt variables. It was evident from the findings that there exists bidirectional causality between public sector external debt and economic growth. Causality between private external debt and economic growth has been found to be insignificant. However, causality between domestic debt and economic growth showed a unidirectional causality from domestic debt to economic growth and not vice versa. Causality tests suggest that impact of domestic debt on economic growth is more effective compared to external debts.

• International Commerce and Information Review
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• 제10권1호
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• pp.329-347
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• 2008

The purpose of this study is to examine the causal relationship between the exchange rate and economic growth, and to induce policy implications. In order to test whether time series data is stationary and the model is fitness or not, we put in operation unit root test, cointegration test. And we apply Granger causality based on an error correction model. The results indicate that uni-dierctional causality between exchange rate and economic growth is detected. Exchange rate impacts on economic growth, but economic growth don't impact on exchange rate. The analysis of impulse reaction function shows that the impulse of exchange rate impacts on Korean economic growth in negative direction. We can infer policy suggestion as follows: The fluctuation of exchange rate much affects economic growth, thus we must make a stable policy of exchange rate to continue economic growth.