• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.384-392
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• 2022

The objective of this study was to estimated nitrogen content and chlorophyll using RGB, Hyperspectral sensors to diagnose of nitrogen nutrition in apple tree leaves. Spectral data were acquired through image processing after shooting with high resolution RGB and hyperspectral sensor for two-year-old 'Hongro/M.9' apple. Growth data measured chlorophyll and leaf nitrogen content (LNC) immediately after shooting. The growth model was developed by using regression analysis (simple, multi, partial least squared) with growth data (chlorophyll, LNC) and spectral data (SPAD meter, color vegetation index, wavelength). As a result, chlorophyll and LNC showed a statistically significant difference according to nitrogen fertilizer level regardless of date. Leaf color became pale as the nutrients in the leaf were transferred to the fruit as over time. RGB sensor showed a statistically significant difference at the red wavelength regardless of the date. Also hyperspectral sensor showed a spectral difference depend on nitrogen fertilizer level for non-visible wavelength than visible wavelength at June 10th and July 14th. The estimation model performance of chlorophyll, LNC showed Partial least squared regression using hyperspectral data better than Simple and multiple linear regression using RGB data (Chlorophyll R²: 81%, LNC: 81%). The reason is that hyperspectral sensor has a narrow Full Half at Width Maximum (FWHM) and broad wavelength range (400-1,000 nm), so it is thought that the spectral analysis of crop was possible due to stress cause by nitrogen deficiency. In future study, it is thought that it will contribute to development of high quality and stable fruit production technology by diagnosis model of physiology and pest for all growth stage of tree using hyperspectral imagery.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.1
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• pp.61-69
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• 2009

Statement of problem: Porcelain veneers have become a popular treatment modality for aesthetic anterior prosthesis. Fitting porcelain veneers in the mouth usually involve a try-in appointment, which frequently results in salivary contamination of fitting surfaces. Purpose: An in vitro study was carried out to investigate the effect of silane treatment timing and saliva contamination on the resin bond strength to porcelain veneer surface. Material and methods: Cylindrical test specimens (n=360) and rectangular test specimens (n=5) were prepared for shear bond test and contact angle analysis. Whole cylindrical specimens divided into 20 groups, each of which received a different surface treatment and/or storage condition. The composite resin cement stubs were light-polymerized onto porcelain adherends. The shear bond strengths of cemented stubs were measured after dry storage and thermocycling (3,000 cycles) between 5 and $55^{\circ}C$. The silane and their reactions were chemically monitored by using Fourier Transform Infrared Spectroscopy analysis (FTIR) and contact angle analysis. One-way analysis of variance (ANOVA) and Dunnett's multiple comparison were used to analyze the data. Results: FT-IR analysis showed that salivary contamination and silane treatment timing did not affect the surface interactions of silane. Observed water contact angles were lower on the saliva contaminated porcelain surface and the addition of 37% phosphoric acid for 20 seconds on saliva contaminated porcelain increased the degree of contact angle. Silane applied to the porcelain, a few days before cementation, resulted in increasing the bond strength after thermocycling. Conclusion: Within the limitation of this study, it can be concluded that it would be better to protect porcelain prosthesis before saliva contamination with silane treatment and to clean the contaminated surface by use of phosphoric acid.

• Horticultural Science & Technology
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• v.29 no.3
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• pp.211-216
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• 2011

This study was carried out to clarify precise $CO_2$ demands of paprika plants (Capsicum annumm L.) by measuring photosynthesis rates of the leaves in high, low positions, and the $CO_2$ consumption of a whole plant in a large sealed chamber. A photosynthesis measuring system (LI-6400) was used to measure the photosynthetic rates of the leaves located in different positions. A large sealed chamber that can control inside environmental factors was developed for measuring $CO_2$ consumption by a whole paprika plant. With increase of radiation, photosynthetic rates of the leaves in higher position became larger than those in lower position. The $CO_2$ consumption by the plant was estimated by using decrement of $CO_2$ concentration from initial level of 1500 ${\mu}mol{\cdot}mol^{-1}$ in the chamber with increase of integrated radiation. A regression model for estimating $CO_2$ consumption by the plant (leaf area = 7,533.4 $cm^2$) was expressed with integrated radiation (x) and was suggested as $y=-0.06234+3.671^*x/(2.589+x)$ ($R^2=0.9966^{***}$). The photosynthetic rate of the whole plant measured in the chamber was 3.4 ${\mu}mol\;CO_2{\cdot}m^{-2}{\cdot}s^{-1}$ under 300 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ light intensity, which is in-between photosynthetic rates of the leaves in high and low positions. For this reason, some differences between required and supplied $CO_2$ amounts in greenhouses might occur when depending too much on photosynthetic rates of leaves. Therefore, we can estimate more accurately $CO_2$ amount required in commercial greenhouses by using $CO_2$ consumption model of a whole plant obtained in this study in addition to leaf photosynthetic rate.

• Korean Journal of Ecology and Environment
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• v.52 no.2
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• pp.118-125
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• 2019

Swimming performance of fish is an important factor in the survival of fish. Also, swimming performance of fish is used in the form of habitat, or as a condition to consider when creating a fish ladder. However in Korea, researches in swimming performance of Korean freshwater fish were scarce and inadequate in some part, thus fish ladders were installed without considering their swimming performance. Therefore, in this study, we measured swimming performance of 4 Korean freshwater fish species to consider importance of swimming performance test. The fish used in this study were Carassius auratus, Zacco koreanus, Gnathopogon strigatus, Acheilognathus lanceolata intermedia species which was collected during October to November, 2018 at Geum River, and measurement for swimming speed of each fish was done by using $Loligo^{(R)}$ System, swim tunnel respirometer in January to February of 2019. The average value of the burst critical swimming speed ($U_{crit}$) for each species was $0.8{\pm}0.04m\;s^{-1}$ for C. auratus, $0.77{\pm}0.04m\;s^{-1}$ for Z. koreanus, $0.95{\pm}0.04m\;s^{-1}$ for G. strigatus, $0.73{\pm}0.03m\;s^{-1}$ for A. lanceolata intermedia and the average value of prolonged critical swimming speed was $0.54m\;s^{-1}$ for C. auratus, $0.67m\;s^{-1}$ for Z. koreanus, $0.7m\;s^{-1}$ for G. strigatus, $0.54m\;s^{-1}$ for A. lanceolata intermedia. Since the fish used in this experiment were collected from a small part of the water system in Korea and there were only 4 species, they were not enough to represent the species that inhabit the entire Korean water system. It will be necessary to continue evaluating the swimming performance of other freshwater species in Korea.

• Journal of the Korean earth science society
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• v.43 no.2
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• pp.239-252
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• 2022

Quality control methods for the first G-band vapor radiometer (GVR) mounted on a weather aircraft in Korea were developed using the GVR Precipitable Water Vapor (PWV). The aircraft attitude information (degree of pitch and roll) was applied to quality control to select the shortest vertical path of the GVR beam. In addition, quality control was applied to remove a GVR PWV ≥20 mm. It was found that the difference between the warm load average power and sky load average power converged to near 0 when the GVR PWV increased to 20 mm or higher. This could be due to the high brightness temperature of the substratus and mesoclouds, which was confirmed by the Communication, Ocean and Meteorological Satellite (COMS) data (cloud type, cloud top height, and cloud amount), cloud combination probe (CCP), and precipitation imaging probe (PIP). The GVR PWV before and after the application of quality control on a cloudy day was quantitatively compared with that of a local data assimilation and prediction system (LDAPS). The Root Mean Square Difference (RMSD) decreased from 2.9 to 1.8 mm and the RMSD with Korea Local Analysis and Precipitation System (KLAPS) decreased from 5.4 to 4.3 mm, showing improved accuracy. In addition, the quality control effectiveness of GVR PWV suggested in this study was verified through comparison with the COMS PWV by using the GVR PWV applied with quality control and the dropsonde PWV.