• Journal of Astronomy and Space Sciences
• /
• v.35 no.3
• /
• pp.201-210
• /
• 2018

The characterization of detectors installed in space- and ground-based instruments is important to evaluate the system performance. We report the development of a detector performance test system for astronomical applications using the Andor iKon M CCD camera. The performance test system consists of a light source, monochromator, integrating sphere, and power meters. We adopted the Czerny-Tuner monochromator with three ruled gratings and one mirror, which covers a spectral range of 200-9,000 nm with a spectral resolution of ~1 nm in the visible region. Various detector characteristics, such as the quantum efficiency, sensitivity, and noise, can be measured in wide wavelength ranges from the visible to mid-infrared regions. We evaluated the Korea Astronomy and Space Science Institute (KASI) detector performance test system by using the performance verification of the Andor iKon-M CCD camera. The test procedure includes measurements of the conversion gain ($2.86e^-/ADU$), full well capacity ($130K\;e^-$), nonlinearity, and pixel defects. We also estimated the read noise, dark current, and quantum efficiency as a function of the temperature. The lowest measured read noise is $12e^-$. The dark current at 223 K was determined to be $7e^-/s/pix$ and its doubling temperature is $5.3^{\circ}C{\pm}0.2^{\circ}C$ at an activation energy of 0.6 eV. The maximum quantum efficiency at 223 K was estimated to be $93%{\pm}2%$. We proved that the quantum efficiency is sensitive to the operating temperature. It varies up to 5 % in the visible region, while the variation increases to 30 % in the near-infrared region. Based on the comparison of our results with the test report by the vendor, we conclude that our performance test results are consistent with those from the vendor considering the test environment. We also confirmed that the KASI detector performance test system is reliable and our measurement method and analysis are accurate.

• Korean Journal of Optics and Photonics
• /
• v.21 no.1
• /
• pp.6-11
• /
• 2010

Fluorescent photopolymer film was prepared with composition containing acrylate monomer, binder, a visible light sensitive photo initiator, and fluorescent anthracene polymer. A fluorescent grating pattern was inscribed on the photopolymer film using a 2-beam coupling method. A 514 nm laser was coupled to generate a beam-interference pattern. A highly fluorescent diffractive line pattern was formed on the fluorescent photopolymer within 30 sec. of exposure. The fluorescence intensity was highly enhanced in the patterned area, possibly due to the change in the environment of the fluorescent polymers by the photo-polymerization of monomers. Under a photo-mask, a gap electrode pattern was formed of fluorescent gratings with a sub-micron scale, which was matched well to the calculated value ($2.5\;{\mu}m$ and $0.6\;{\mu}m$) based on the refractive index of the photopolymer and beam incident angle ($3.4^{\circ}$, $15^{\circ}$) to the photopolymer surface.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.02a
• /
• pp.185-185
• /
• 2011

ZnTe semiconductor is very attractive materials for optoelectronic devices in the visible green spectral region because of it has direct bandgap of 2.26 eV. The prototypes of ZnTe light emitting diodes (LEDs) have been reported [1], showing that their green emission peak closely matches the most sensitive region of the human eye. Another application to photovoltaics proved that ZnTe is useful for the production of high-efficiency multi-junction solar cells [2,3]. By using the pulse laser deposition system, ZnTe thin films were deposited on ZnO thin layer, which is grown on (0001) Al2O3substrates. To produce the plasma plume from an ablated ZnO and ZnTe target, a pulsed (10 Hz) YGA:Nd laser with energy density of 95 mJ/$cm^2$ and wavelength of 266 nm by a nonlinear fourth harmonic generator was used. The laser spot focused on the surface of the ZnO and ZnTe target by using an optical lens was approximately 1 mm2. The base pressure of the chamber was kept at a pressure around $10^{-6}$ Torr by using a turbo molecular pump. The oxygen gas flow was controlled around 3 sccm by using a mass flow controller system. During the ZnTe deposition, the substrate temperature was $400^{\circ}C$ and the ambient gas pressure was $10^{-2}$ Torr. The structural properties of the samples were analyzed by XRD measurement. The optical properties were investigated by using the photoluminescence spectra obtained with a 325 nm wavelength He-Cd laser. The film surface and carrier concentration were analyzed by an atomic force microscope and Hall measurement system.

• Journal of Broadcast Engineering
• /
• v.21 no.2
• /
• pp.180-191
• /
• 2016

When up-scaling algorithms for visible light images are applied to infrared (IR) images, they rarely work because IR images are usually blurred. In order to solve such a problem, this paper proposes an up-scaling algorithm for IR images. We employ adaptive dynamic range encoding (ADRC) as a simple classifier based on the observation that IR images have weak details. Also, since human visual systems are more sensitive to edges, our algorithm focuses on edges. Then, we add pre-processing in learning phase. As a result, we can improve visibility of IR images without increasing computational cost. Comparing with Anchored neighborhood regression (A+), the proposed algorithm provides better results. In terms of just noticeable blur, the proposed algorithm shows higher values by 0.0201 than the A+, respectively.

• Microbiology and Biotechnology Letters
• /
• v.50 no.3
• /
• pp.375-386
• /
• 2022

In the present study, four distinctly colored bacterial isolates that show intense pigmentation upon brief ultraviolet (UV) light exposure are chosen. The strains are identified as Micrococcus luteus (Milky yellow), Cryseobacterium pallidum (Yellow), Cryseobacterium spp. (Golden yellow), and Kocuria turfanensis (Pink) based on their morphological and 16S rDNA analysis. Moderate salinity (1.25%), 25-37℃ temperature, and pH of 7.2 are found to be the most favorable conditions of growth and pigment production for all the selected isolates. The pigments are extracted using methanol: chloroform (1:1) and the purity of the pigments are confirmed by high-performance liquid chromatography (HPLC) and thin-layer chromatography (TLC). Further, Fourier transform infrared (FTIR) and UV-Visible spectroscopy indicate their resemblance with carotenoids and flexirubin family. The antioxidant activities of the pigments are estimated, and, all the pigments have shown significant antioxidant efficacy in 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picryl-hydrazyl (DPPH), and ferric reducing antioxidant power (FRAP) assays. The UV protective property of the pigments is determined by cling-film assay, wherein, at least 25% of UV sensitive Escherichia coli survive with bio-pigments even after 90 seconds of UV exposure compared to control. The pigments also hold a good sun protective factor (SPF) value (1.5-4.9) which is calculated with the Mansur equation. Based on these results, it can be predicted that these bacterial pigments can be further developed into a promising antioxidant and UV-protectant for several biomedical applications.

• Korean Journal of Environmental Agriculture
• /
• v.7 no.1
• /
• pp.43-51
• /
• 1988

$SO_2$ gas injuries for 19 varieties of 10 species of plants were investigated within a environmentally controlled growth chamber. Visible injuries were observed when exposing the plants either 0, 0.2, 0.4, 0.7 or 1.5ppm of $SO_2$ gas for 5 days from 9 : 00 to 17 : 00 everyday. The results obtained were as follows: 1. Light brown spots were shown on Raphanus sativus(Chunchu, Taeback, Jinjudaepyung), Brassica campestris(Manchun, Josaengmiho, Seoul, Jeonseung), and Capsicum annum(Searona, Hongsanho, Hongilpum); brown spots on Sesamum indicum(Pungnyun, Kwangsan); reddish brown shades on Cleosia cristata; and black brown spots on Perilla frutescens, Calendula officinalis, Chrysanthemum morifolium, and Salvia splendens, respectively. 2. The spotty injuries induced by $SO_2$ gas injuries for 19 varieties of 10 species of plants were investigated within a environmentally controlled growth chamber. Visible injuries were observed when exposing the plants either 0, 0.2, 0.4, 0.7 or 1.5ppm of $SO_2$ gas for 5 days from 9 : 00 to 17 : 00 everyday. The results obtained were as follows: 1. Light brown spots were shown on Raphanus sativus(Chunchu, Taeback, Jinjudaepyung), Brassica campestris(Manchun, Josaengmiho, Seoul, Jeonseung), and Capsicum annum(Searona, Hongsanho, Hongilpum); brown spots on Sesamum indicum(Pungnyun, Kwangsan); reddish brown shades on Cleosia cristata; and black brown spots on Perilla frutescens, Calendula officinalis, Chrysanthemum morifolium, and Salvia splendens, respectively. 2. The spotty injuries induced by SO₂ gas on Raphanus sativus, Callistephus chinensis, Capsicum annum, Perilla frutescens, Calendula officinalis, Salvia splendens, and Sesamum indicum; the many small spots on Chrysanthemum morifolium; and the brown shade on Celosia cristata appeared on the upper surface of the intervein, on the leaf apex area and on the entire upper surface of leaves, respectively. 3. Visual injuries of Capsicum annum(Chunchu), Perilla frutescens, Sesamum indicum(Pungnyun, Kwangsan), and Salvia splendens were developed at 0.4ppm of SO₂ gas fumigation. Brassica campestris(Jeonseung), Capsicum annum(Searona, Hongilpum), and Cleosia cristata, however, showed the injury at 1.5ppm of $SO_2$ gas concentration. 4. Based on the tolerance grade(time when the 1st injury appeared), Raphanus sativus, Perilla frutescens, Sesamum indicum, and Salvia splendens were the most sensitive plants and Chrysanthemum morifolium, Callistephus chinensis, Cleosia cristata, and Calendula officinalis were the plants most tolerant of $SO_2$ gas. gas on Raphanus sativus, Callistephus chinensis, Capsicum annum, Perilla frutescens, Calendula officinalis, Salvia splendens, and Sesamum indicum; the many small spots on Chrysanthemum morifolium; and the brown shade on Celosia cristata appeared on the upper surface of the intervein, on the leaf apex area and on the entire upper surface of leaves, respectively. 3. Visual injuries of Capsicum annum(Chunchu), Perilla frutescens, Sesamum indicum(Pungnyun, Kwangsan), and Salvia splendens were developed at 0.4ppm of $SO_2$ gas injuries for 19 varieties of 10 species of plants were investigated within a environmentally controlled growth chamber. Visible injuries were observed when exposing the plants either 0, 0.2, 0.4, 0.7 or 1.5ppm of $SO_2$ gas for 5 days from 9 : 00 to 17 : 00 everyday. The results obtained were as follows: 1. Light brown spots were shown on Raphanus sativus(Chunchu, Taeback, Jinjudaepyung), Brassica campestris(Manchun, Josaengmiho, Seoul, Jeonseung), and Capsicum annum(Searona, Hongsanho, Hongilpum); brown spots on Sesamum indicum(Pungnyun, Kwangsan); reddish brown shades on Cleosia cristata; and black brown spots on Perilla frutescens, Calendula officinalis, Chrysanthemum morifolium, and Salvia splendens, respectively. 2. The spotty injuries induced by SO₂ gas on Raphanus sativus, Callistephus chinensis, Capsicum annum, Perilla frutescens, Calendula officinalis, Salvia splendens, and Sesamum indicum; the many small spots on Chrysanthemum morifolium; and the brown shade on Celosia cristata appeared on the upper surface of the intervein, on the leaf apex area and on the entire upper surface of leaves, respectively. 3. Visual injuries of Capsicum annum(Chunchu), Perilla frutescens, Sesamum indicum(Pungnyun, Kwangsan), and Salvia splendens were developed at 0.4ppm of SO₂ gas fumigation. Brassica campestris(Jeonseung), Capsicum annum(Searona, Hongilpum), and Cleosia cristata, however, showed the injury at 1.5ppm of $SO_2$ gas concentration. 4. Based on the tolerance grade(time when the 1st injury appeared), Raphanus sativus, Perilla frutescens, Sesamum indicum, and Salvia splendens were the most sensitive plants and Chrysanthemum morifolium, Callistephus chinensis, Cleosia cristata, and Calendula officinalis were the plants most tolerant of $SO_2$ gas. gas fumigation. Brassica campestris(Jeonseung), Capsicum annum(Searona, Hongilpum), and Cleosia cristata, however, showed the injury at 1.5ppm of $SO_2$ gas concentration. 4. Based on the tolerance grade(time when the 1st injury appeared), Raphanus sativus, Perilla frutescens, Sesamum indicum, and Salvia splendens were the most sensitive plants and Chrysanthemum morifolium, Callistephus chinensis, Cleosia cristata, and Calendula officinalis were the plants most tolerant of $SO_2$ gas.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.45 no.3
• /
• pp.1-8
• /
• 2017

The present study aimed to investigate the effect of calcium chloride($CaCl_2$) on the growth and physiological responses of Pinus strobus and the variables that are sensitive to $CaCl_2$. Thus, changes in the visible damage, growth of root collar diameter, plant water content, chlorophyll content and composition, maximum PS II photochemical efficiency, and electron transport rate of P. strobus was analyzed in relation to treatment witih $CaCl_2$. A $CaCl_2$ solution(0.5, 1.0 and 3.0%) was applied in the root zone before leaf unfolding. Leaf browning, defoliation, and drying were observed with $CaCl_2$ application and this pattern was aggravated as the $CaCl_2$ concentration increased and the treatment period became longer. The decrease of growth in root collar diameter and height and leaf water content were observed at $CaCl_2$ 1.0% and 3.0%. The total chlorophyll content indicated that photopigment, PS II photochemical efficiency and electron transport rate significantly decreased at $CaCl_2$ 3.0%. In conclusion, $CaCl_2$ affected leaf water content and led to a decrease of capability in light harvesting and photochemical responses. Also, as a result of the correlation between calcium chloride concentration and growth and physiological response parameters, it was found that the leaf moisture content and the ratio of chlorophyll a and b reflect the damage level of calcium chloride sensitively because their coefficient of determinations were relatively high.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.11 no.4
• /
• pp.143-150
• /
• 2009

Deicing salt is used to melt snow and ice on the road for traffic safety during the winter season, which accumulates in the roadside vegetation and induces visible injuries. The damage may accelerate particularly when it coincides with early spring leaf out. In order to better understand the response mechanisms, C. kousa (3-year-old) was irrigated twice prior to leaf bud in a rhizosphere with solutions of 0.5, 1.0, and 3.0% calcium chloride ($CaCl_2$) concentration, that were made by using an industrial $CaCl_2$ reagent practical deicing material in Seoul. Physiological traits of the mature leaves were progressively reduced by $CaCl_2$ treatment, resulting in reductions of total chlorophyll contents, chlorophyll a:b, photosynthetic rate, quantum yield, stomatal conductance, $F_V/F_M$, and NPQ. On the contrary, light compensation point and dark respiration were increased at high $CaCl_2$ concentration. A decrease in intercellular $CO_2$ concentration by stomatal closure first resulted in a reduced photosynthetic rate and then was accompanied by low substance metabolic rates and photochemical damage. Based on the reduction of physiological activities at all treatments ($CaCl_2$ 0.5%, 1.0%, and 3.0%), C. kousa was determined as one of the sensitive species to $CaCl_2$.

• Horticultural Science & Technology
• /
• v.28 no.5
• /
• pp.719-727
• /
• 2010

Reduced irradiance promotes shoot elongation depending on developmental stage and environmental factors and decreases plant quality in $Cyclamen$ $persicum$ Mill. To determine the petiole elongation responses to low irradiance, 'Metis Scarlet Red' cyclamen at different developmental stages [juvenile (5-6 unfolded leaves), transitional (1-3 visible flower buds), or mature (1-3 elongating peduncles)] was grown in growth modules at 60 (low light, LL) or 240 (high light, HL) ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD within the growth chambers at different temperatures [16/12 (low temperature, LT), 22/18 (medium temperature, MT), or 28/$24^{\circ}C$ (high temperature, HT) (day/night)]. In Experiment I, juvenile plants were either kept in an LL or HL module during the entire treatment of 4 weeks or were transferred to the other module at 1, 2, or 3 weeks after treatment in an MT chamber. In Experiment II, juvenile, transitional, or mature plants were moved to the HL module at 0, 3, 6, 9, or 12 days after being placed in the LL module at the MT chamber and grown for 21 days. In Experiment III, transitional plants were moved to the HL module at 0, 3, 6, 9, or 12 days after being placed in the LL module at the LT, MT, or HT chambers. As the exposure duration to LL increased from 0 to 4 weeks or from 0 to 12 days, petiole length and plant height increased at all temperatures and developmental stages. In Experiment I, the exposure to LL during the latter period, rather than the early period, increased elongation rate. In Experiment II, petiole elongation in transitional plants was more sensitive to LL than juvenile or mature plants during the early period of the treatment for 12 days. In Experiment III, petiole length increased with increasing temperature and exposure duration to LL. Petiole elongation rate at HT increased rapidly from the beginning of LL exposure as compared to LT. Increase of $6^{\circ}C$ in temperature had the similar effect to LL exposure for 3 days in petiole elongation. To conclude, transitional cyclamen under higher temperatures responds more immediately to low irradiance and elongates its petioles.