• 천문학회보
• /
• 제37권2호
• /
• pp.107.1-107.1
• /
• 2012

We present the results of far-ultraviolet (FUV) observations of comet C/2001 Q4 (NEAT) obtained with Far-ultraviolet Imaging Spectrograph (FIMS) on board the Korean microsatellite STSAT-1, which operated at an altitude of 700 km in a sun-synchronous orbit. FIMS is a dual-channel imaging spectrograph (S channel 900-1150 ${\AA}$, L channel 1350-1750 ${\AA}$, ${\lambda}/{\Delta}{\lambda}$ ~ 550) with large image fields of view (S: $4^{\circ}.0{\times}4^{\prime}.6$, L: $7^{\circ}.5{\times}4^{\prime}.3$, angular resolution 5'-10') optimized for the observation of diffuse emission of astrophysical radiation. Comet C/2001 Q4 (NEAT) was observed with a scanning survey mode when it was located around the perihelion between 8 and 15 May 2004. Several important emission lines were detected including S I (1425, 1474 ${\AA}$), C I (1561, 1657 ${\AA}$) and several emission lines of CO $A^1{\Pi}-X^1{\Sigma}^+$ system in the L channel. Production rates of the notable molecules, such as C I, S I and CO, were estimated from the photon fluxes of these spectral lines and compared with previous observations. We compare the flux and the production rates in the radius of $3{\times}10^5$ km with $20{\times}10^5$ km from the central coma. We obtained L-channel image which have map size $5^{\circ}{\times}5^{\circ}$ The image was constructed for the wavelength band of L-channel (1350 - 1710 ${\AA}$. We also present the radial profiles of S I, C I, CO obtained from the spectral images of the central coma. The radial profiles of $2{\times}10^6$ km region are compared with the Haser model.

• 한국환경농학회지
• /
• 제30권4호
• /
• pp.382-389
• /
• 2011

BACKGROUND: Light-emitting diodes (LEDs) with lower electric cost and the specific wavelength have been considering as a novel light source for plant production in greenhouse conditions as well as in a closed culture system. Supplementary lighting for day-length extension was considered as light intensity, light quality, and/or photoperiod control on plant growth and development. Effects of supplementary blue or red LED radiation with lower light intensity on growth of Ageratum (Ageratum houstonianum Mill., cv. Blue Field), African marigold (Tagetes erecta L., cv. Orange Boy), and Salvia (Salvia splendens F. Sello ex Ruem & Schult., cv. Red Vista) were discussed during sunrise and sunset twilight in the experiment. METHODS AND RESULTS: Supplementary lighting by blue and red LEDs for 30 (Treatment B30; R30) or 60 (Treatment B60; R60) min. per day were established in greenhouse conditions. Photosynthetic photon flux for supplementary radiation was kept at $15{\mu}mol\;m^{-2}\;s^{-1}$ on the culture bed. Natural condition without supplementary light was considered as a control. The highest shoot and root dry weights were shown in African marigold exposed by red light for 60 min. per day. Supplementary blue and red lighting regardless of the radiation time significantly stimulated development of lateral branches in African marigold. Stem growth in Ageratum and Salvia seedlings was significantly promoted by red radiation as well as natural light. CONCLUSIONS: Extending of the radiation time at sunrise and sunset twilight using LEDs stimulated reproductive growth of flowering plant species. Different characteristics on growth under supplementary blue or red lighting conditions were also observed in the seedlings during supplementary radiation.

• 원예과학기술지
• /
• 제34권1호
• /
• pp.55-66
• /
• 2016

This study was carried out to investigate the effect of artificial light sources with different light qualities on the growth and flowering characteristics of a herbaceous long-day plant, Petunia ${\times}$ hybrida Hort. Seedlings of petunia cultivar 'Madness Rose' were potted, acclimated for one week, and grown in a phytotron equipped with tube- and bulb-type fluorescent lamps (FL tube and bulb), tube-type white light-emitting diodes (LED tube), halogen lamps (HL), metal halide lamps (MH), and high pressure sodium lamps (HPS) for 10 weeks. The temperature, photoperiod, and photosynthetic photon flux density (PPFD) in the phytotron were $22{\pm}2^{\circ}C$, 16 h, and $25{\pm}2{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, respectively. Light sources combined with HL promoted stem elongation, and plant height and internode length decreased with increasing red to far-red (R:FR) ratio. FL tube + LED tube, HPS, and FL tube promoted branching, whereas plants grown under light sources combined with HL did not have any branches. Days to flowering (from longest to shortest) occurred as follows: FL tube + HL > FL tube + HL > MH > HPS = FL tube + FL bulb > FL tube + LED tube > LED tube > FL tube, indicating that reducing the R:FR ratio of the light sources promoted flowering. Only 20% of plants grown under an FL tube flowered, whereas under all other treatments, 100% of plants flowered. At 10 weeks after treatment, plants grown under HPS and MH had (cumulatively) 12 open flowers, and those grown under FL tube + FL bulb, LED tube, FL tube + LED tube, and HPS treatment had approximately seven flower buds. These results suggest that light sources with low R:FR ratios promote flowering and stem elongation in petunia, but they reduce its ornamental value due to overgrowth and poor branching.

• 화훼연구
• /
• 제19권1호
• /
• pp.49-54
• /
• 2011

본 연구는 우리나라 무스카리 우점품종인 'Early Giant'의 대량증식 체계를 구축하기 위하여 잎 절편으로부터 소인경 형성과 비대에 미치는 MS 무기염 농도, 당 농도 및 광조건의 영향을 조사하였다. 무스카리의 잎 절편을 2주간 암 배양 후 MS 기본배지에 NAA $0.01mg{\cdot}L^{-1}$, kinetin $0.2m{\cdot}L^{-1}$, 자당 $30g{\cdot}L^{-1}$와 gelrite $3g{\cdot}L^{-1}$가 첨가된 배지에 16시간 일장으로 명 배양하였을 때 자구형성 및 생육이 가장 양호하였다. 다만, 자구 비대는 MS 배지 내 $60g{\cdot}L^{-1}$ 당 농도에서 촉진되었다. 온실에서 순화된 식물체는 정상적으로 개화하였으며 정식 2년차에 1.5개 내외의 자구를 가진 구를 생산할 수 있었다.

• Nuclear Engineering and Technology
• /
• 제54권10호
• /
• pp.3855-3863
• /
• 2022

An evaluation of the radiation shielding performance of high-Z-particle-loaded polylactic acid (PLA) composite materials was pursued. Specimens were produced via fused deposition modeling (FDM) using copper-PLA, steel-PLA, and BaSO₄-PLA composite filaments containing 82.7, 75.2, and 44.6 wt% particulate phase contents, respectively, and were tested under broad-band flash x-ray conditions at the Sandia National Laboratories HERMES III facility. The experimental results for the mass attenuation coefficients of the composites were found to be in good agreement with GEANT4 simulations carried out using the same exposure conditions and an atomistic mixture as a model for the composite materials. Further simulation studies, focusing on the Cu-PLA composite system, were used to explore a shield design parameter space (in this case, defined by Cu-particle loading and shield areal density) to assess performance under both high-energy photon and electron fluxes over an incident energy range of 0.5-15 MeV. Based on these results, a method is proposed that can assist in the visualization and isolation of shield parameter coordinate sets that optimize performance under targeted radiation characteristics (type, energy). For electron flux shielding, an empirical relationship was found between areal density (AD), electron energy (E), composition and performance. In cases where ${\frac{E}{AD}}{\geq}2MeV{\bullet}cm{\bullet}g^{-1}$, a shield composed of >85 wt% Cu results in optimal performance. In contrast, a shield composed of <10 wt% Cu is anticipated to perform best against electron irradiation when ${\frac{E}{AD}}<2MeV{\bullet}cm{\bullet}g^{-1}$.

• 한국물환경학회지
• /
• 제38권6호
• /
• pp.282-291
• /
• 2022

Since the efficiency of wastewater treatment using microalgae differs depending on the metabolic characteristics of the species, it is important to understand the characteristics of target algae prior to the application in wastewater treatment. In this study, for the application of Arthrospira platensis to wastewater treatment, which is a filamentous alkaliphilic cyanobacteria, basic species specificity was identified and the possibility of application to wastewater treatment was investigated. As a result of the species specificity investigation, the specific growth rate between pH 7.0 and 11.0 showed the highest value near pH 9 at 0.25/day. The reason for the relatively low growth(0.08/day) at pH 11 was thought to be the CA(carbonic anhydrase) enzyme that is involved in carbon fixation during photosynthesis has the highest activity at pH 8.0 to 9.0, and at pH 11, CA activity was relatively low. In addition, A. platensis showed optimal growth at 400 PPFD(photosynthetic photon flux density) and 30℃, and this means that cyanobacteria such as A. platensis have a larger number of PS-I(photosystem I) than that of PS-II(photosystem II). It was speculated that it was because higher light intensity and temperature were required to sufficiently generate electrons to transfer to PS-I. Regarding the applicability of A. platensis, it was suggested that if a system using the synergistic effect of co-culture of A. platensis and bacteria was developed, a more efficient system would be possible. And different from single cocci, filamentous A. platensis expected to have a positive impact on harvesting, which is very important in the latter part of the wastewater treatment process.

• 한국수산과학회지
• /
• 제56권6호
• /
• pp.878-888
• /
• 2023

Growth responses of Chlorella vulgaris exposed to different light intensities and wavelengths of light-emitting diodes (LEDs) were investigated. C. vulgaris was cultured under red LED (650 nm), blue LED (450 nm), green LED (520 nm), and fluorescent lamps (three wavelengths, control). The maximum growth rates (µ_max) of C. vulgaris were highest under the blue LED, followed by the red LED, green LED, and fluorescent lamps. The low compensation photon flux density (I₀) and low half-saturation constants (K_s) were observed in C. vulgaris cultured under the red LED, indicating that high C. vulgaris growth is closely related to the low light intensity of the red LED suggesting that the red LED can be useful for the biomass production of C. vulgaris. Furthermore, it was observed that under the blue LED during the stationary phase, there was an increase in useful bioactive substances, such as proteins and lipids, which are beneficial for biomass production. In conclusion, the red LED is an economical light source that can enhance cell density, and the blue LED is effective in promoting valuable intracellular substances.

• 한국환경과학회지
• /
• 제33권7호
• /
• pp.501-509
• /
• 2024

Prunus mume is a culturally significant fruit tree in East Asia that is widely used in traditional foods and medicines. The present study investigated the effects of sunlight exposure and leaf position on the photosynthetic efficiency of P. mume using SPAD values. The study was conducted at Cheongju National University of Education, Korea, under contrasting conditions between sunny (Site A) and shaded (Site B) areas on P. mume trees. Over three days, under varied weather, photosynthetic photon flux density (PPFD) and SPAD measurements were collected using a SPAD-502 plus chlorophyll meter and a smartphone PPFD meter application. The SPAD values of the 60 leaves were measured in triplicate for each tree. The results indicated that trees in sunny locations consistently exhibited higher SPAD values than those in shaded areas, implying greater photosynthetic efficiency. Moreover, leaves positioned higher in the canopy showed increased photosynthetic efficiency under different light conditions, underscoring the significance of leaf placement and light environment in photosynthetic optimization. Despite the daily sunlight variability, these factors maintained a consistent influence on SPAD values. This study concludes that optimal leaf positioning, influenced by direct sunlight exposure, significantly enhances photosynthetic efficiency in P. mume. These findings highlight the potential of integrating smart farming techniques, especially open-field smart farming technology, to improve photosynthesis and, consequently, crop yield and efficiency. The findings also highlight the need for further exploration of environmental factors affecting photosynthesis for agricultural advancement.

• 생물환경조절학회지
• /
• 제22권4호
• /
• pp.400-407
• /
• 2013

본 연구는 식물공장용으로 방전램프로서 메탈할라이드램프(MH), 고압나트륨램프(HPS), 제논램프(XE)를 사용하고, 냉백색형광등(FL)을 대조구로 사용한 가운데 상추(Lactuca sativa L. cv. Jeokchima)의 생육 및 파이토케미컬의 특성을 분석하고자 수행되었다. 식물공장 내부의 환경조건은 광주기 16/8h, 광합성유효광양자속(photosynthetic photon flux, PPF) $200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, 기온 $22/18^{\circ}C$, 습도 70%, $CO_2$ 농도 $400{\mu}mol{\cdot}mol^{-1}$로 조절하였다. 각 램프의 분광 특성을 이용하여 PPF에 대한 청색광 영역(400~500nm), 녹색광 영역(500~600nm), 적색광 영역(600~700nm)의 비율을 계산하였다. MH램프의 청색광 영역은 23.0%로서 다른 처리구에 비해서 가장 높게 나타났다. 한편 HPS램프의 청색광 영역은 4.7%로서 가장 낮게 나타났으나, 적색광 영역은 38.0%로서 다른 처리구에 비해서 높게 나타났다. 정식 후 11일째와 21일째에 측정된 상추의 엽장, 엽폭, 엽면적, 지상부 생체중 및 건물중은 방전램프의 광질에 따른 유의차가 나타날 정도로 다르게 나타났다. HPS 처리구의 엽면적은 $143,486mm^2$로서 대조구의 $98,474mm^2$에 비해서 45.7% 크게 나타났으며, MH와 XE 처리구는 대조구에 비해서 각각 16.3%, 9.5%로 크게 나타났다. 이러한 결과는 지상부 생체중에서도 유사하게 나타났다. 적색광 영역의 비율이 높은 HPS 처리구에서는 상추의 잎 관련 생장 특성에서 최대치가 나타났으나, 청색광 영역의 비율이 높은 MH와 XE 처리구에서는 낮게 나타났다. 방전등 처리구에 따라 상추 잎에 축적된 아스코르빈산 함량은 대조구에 비해서 작게 나타났으며, 처리구 사이에 유의차가 인정되지 않았다. 상추 잎의 안토시아닌 함량은 MH 처리구에서 0.70mg/100g으로 최대치가 나타났으며, XE와 HPS 처리구는 대조구의 0.58mg/100g에 비해서 각각 79.3%, 8.6%수준이었다. 결과적으로 방전램프의 종류에 따라 상추의 생장 특성, 아스코르빈산 및 안토시아닌 함량이 다르게 나타났다. 따라서 식물공장용 인공광원으로서 방전램프를 효율적으로 활용하면서, 상추의 생장 및 파이토케미컬 함량을 증진시키기 위해서는 분광 특성이 상이한 방전램프의 병용 또는 단색광 LED의 추가 설치 등과 같은 방전램프의 광질 개선이 요구된다.

• 생물환경조절학회지
• /
• 제20권3호
• /
• pp.182-188
• /
• 2011

본 연구는 LED(light-emitting diode) 보광이 온실에서 키운 어린 고추의 생장과 식물성 화학물질(phytochemical) 함량에 미치는 영향을 조사하였다. 처리한 LED광원은 청색광(470nm), 적색광 (660nm), 청색 + 적색광, 근적색광(740nm), 그리고 자외선(UV-B 300nm)이며. 실험기간 중의 이들 광원의 Photon flux는 각각 49, 16, 40, 5.0, 그리고 $0.82{\mu}mol\;m^{-2}s^{-1}$이었다. LED 광은 낮 동안 16시간이며 UV-B 는 일몰 후 10분간 발아 후 12일간 매일 처리되었다. 실험 결과, 광처리는 무처리에 비하여 고추의 생장과 식물성 화학물질(phytochemical) 함량에 상당한 변화를 보였다. 적색광 처리는 고추의 엽수, 마디수, 엽폭과 생체중을 각각 약 34%, 27%, 50%와 40% 증가되었다. 청색광 처리도 엽장을 약 13% 증가시켰고, 근적색광 처리에 의해 경장과 절간장을 각각 17%와 34% 정도 증가시켰다. 파종 15일에 수확한 고추 잎의 총 안토시아닌(anthocyanin)과 엽록소(chlorophyll) 함량은 청색광 처리에서 무처리에 비해 각각 6배와 2배가 증가하였다. 적색광은 총 페놀성화합물(phenolic compound) 함량을 최소 2배로 증가시켰으며, 반면에 근적색광은 아스코르빅 산(ascorbic acid)과 항산화능(antioxidant activity)을 각각 31%와 66%를 감소시켰다.