• Title/Summary/Keyword: Dark spots

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A Study on Sky Light Pollution based on Sky Glow in Jeju Island (스카이글루 분석을 통한 제주도 빛공해 실태조사)

  • Lee, So-Hyun;Lim, Hong-Soo
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.34 no.4
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    • pp.83-91
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    • 2018
  • Artificial lighting contributes greatly to developing civilizations. It allows daytime activities to continue throughout the dark hours of the day and thus increasing work productivity as well as allowing people to enjoy nighttime activities. In addition, artificial lighting is used to beautify landscapes, architectural monuments, and thus highlighting the social-economic development of a given place. However, excessive and improper usage of artificial lighting can lead to light pollution. Light pollution is a serious issue that is detrimental to human health. It has been linked to a number of health conditions including sleep disorder, visual discomfort as well as cancer. The effects of light pollution extend throughout the entire ecosystem, affecting both plants and animals. Furthermore, sky-glow from light pollution hinders astronomical observation. The current paper presents a study conducted on lit environment of a nightscape. The quality of the sky was measured in 144 spots using Sky Quality Meter (SQM) devices. The measured spots were chosen on the basis of land use as well as distance from the Halla Mountain.

CERAMOGRAPHY ANALYSIS OF MOX FUEL RODS AFTER AN IRRADIATION TEST

  • Kim, Han-Soo;Jong, Chang-Yong;Lee, Byung-Ho;Oh, Jae-Yong;Koo, Yang-Hyun
    • Nuclear Engineering and Technology
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    • v.42 no.5
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    • pp.576-581
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    • 2010
  • KAERI (Korea Atomic Energy Research Institute) fabricated MOX (Mixed Oxide) fuel pellets as a cooperation project with PSI (Paul Scherrer Institut) for an irradiation test in the Halden reactor. The MOX pellets were fitted into fuel rods that included instrumentation for measurement in IFE (Institutt for Energiteknikk). The fuel rods were assembled into the test rig and irradiated in the Halden reactor up to 50 MWd/kgHM. The irradiated fuel rods were transported to the IFE, where ceramography was carried out. The fuel rods were cut transversely at the relatively higher burn-up locations and then the radial cross sections were observed. Micrographs were analyzed using an image analysis program and grain sizes along the radial direction were measured by the linear intercept method. Radial cracks in the irradiated MOX were observed that were generally circumferentially closed at the pellet periphery and open in the hot central region. A circumferential crack was formed along the boundary between the dark central and the outer regions. The inner surface of the cladding was covered with an oxide layer. Pu-rich spots were observed in the outer region of the fuel pellets. The spots were surrounded by many small pores and contained some big pores inside. Metallic fission product precipitates were observed mainly in the central region and in the inside of the Pu spots. The average areal fractions of the metallic precipitates at the radial cross section were 0.41% for rod 6 and 0.32% for rod 3. In the periphery, pore density smaller than 2 ${\mu}m$ was higher than that of the other regions. The grain growth occurred from 10 ${\mu}m$ to 12 ${\mu}m$ in the central region of rod 6 during irradiation.

A high-density gamma white spots-Gaussian mixture noise removal method for neutron images denoising based on Swin Transformer UNet and Monte Carlo calculation

  • Di Zhang;Guomin Sun;Zihui Yang;Jie Yu
    • Nuclear Engineering and Technology
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    • v.56 no.2
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    • pp.715-727
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    • 2024
  • During fast neutron imaging, besides the dark current noise and readout noise of the CCD camera, the main noise in fast neutron imaging comes from high-energy gamma rays generated by neutron nuclear reactions in and around the experimental setup. These high-energy gamma rays result in the presence of high-density gamma white spots (GWS) in the fast neutron image. Due to the microscopic quantum characteristics of the neutron beam itself and environmental scattering effects, fast neutron images typically exhibit a mixture of Gaussian noise. Existing denoising methods in neutron images are difficult to handle when dealing with a mixture of GWS and Gaussian noise. Herein we put forward a deep learning approach based on the Swin Transformer UNet (SUNet) model to remove high-density GWS-Gaussian mixture noise from fast neutron images. The improved denoising model utilizes a customized loss function for training, which combines perceptual loss and mean squared error loss to avoid grid-like artifacts caused by using a single perceptual loss. To address the high cost of acquiring real fast neutron images, this study introduces Monte Carlo method to simulate noise data with GWS characteristics by computing the interaction between gamma rays and sensors based on the principle of GWS generation. Ultimately, the experimental scenarios involving simulated neutron noise images and real fast neutron images demonstrate that the proposed method not only improves the quality and signal-to-noise ratio of fast neutron images but also preserves the details of the original images during denoising.

Brown Ring Spot on Leaves of Kiwifruit Caused by Alternaria alternata (Alternaria alternata에 의한 참다래 갈색둥근무늬병)

  • Jeong, In-Ho;Kim, Gyung-Hee;Lim, Myoung-Taek;Hur, Jae-Seoun;Shin, Jong-Sup;Koh, Young-Jin
    • Research in Plant Disease
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    • v.14 no.1
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    • pp.68-70
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    • 2008
  • Brown leaf spots on leaves of kiwifruit(Actinidia deliciosa) were observed at farmers' orchards in Suncheon and Goheung, Jeonnam Province, Korea in June, 2006. They developed to form dark brown ring spots and severely infected leaves resulted in defoliation during the growing season of kiwifruit. Alternaria sp. was isolated from the diseased leaves repeatedly and was identified as Alternaria alternata on the basis of its mycological characteristics on potato dextrose agar and its pathogenicity was confirmed by wound inoculation on healthy leaves of kiwifruit. A. alternata formed gray to dark sooty gray colony and produced numerous conidia on potato dextrose agar. The conidia, commonly in long chains of 5 or more produced on conidiophores, have $3{\sim}5$ transverse and $1{\sim}2$ longitudinal septa and mostly ovoid or obclavate in shape and were pale brown golden brown in color. The condia were $16.5{\sim}42.1{\times}6.7{\sim}19.5\;{\mu}m$ in size and conidiophores were $8.6{\sim}112.7\;{\mu}m$ in length. This is the first report on the brown ring spot on leaves of kiwifruit caused by A. alternata in Korea.

Occurrence of Eggplant Scab Caused by Cladosporium cucumerinum in Korea

  • Kwon, Jin-Hyeuk;Kang, Soo-Woong;Park, Chang-Seuk
    • The Plant Pathology Journal
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    • v.15 no.6
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    • pp.345-347
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    • 1999
  • A scab disease on eggplant (Solanum melongena L. cv. Chukyang) in plastic film houses around Kimhae area in Korea during the winter season of 0998-1999. The disease started on leaves with small dark brown spots which were gradually expanded to 1 to 3 mm diameter lesions. Later, the central parts of the lesions became collapsed and detached to make holes. Dark brown mold was grown out of the lesions on the lower side of leaf. Numerous conidia were produced on the lower side of leaf. Numerous conidia were produced on the diseased leaves and appeared to be readily dispersed in the air. A fungus was isolated from the diseased leaves, and tested for Koch's postulates to prove the causal agent of the desease. The isolated fungus grew on potato dextrose agar, forming greenish black to pale brown colonies. Conidia were ellipsoidal, fusiform or subspherical, mostly one-celled but occasionally septated, and formed in long branched chains on the erected conidiophores which were pale olevaceous brown and variable in length between 12.4 and $393.4\mu\textrm{g}$. The fungus was identified as Cladosporium cucumerinum Ellis Arthur based on the above morphological characteristics examined. The optimum temperature for mycelial growth and conidial formation was about 20 to $25^{\circ}$. In addition to cucumber, the fungus was also pathogenic to watermelon, pumpkin and oriental melon. This is the first report on the scab disease of eggplant in Korea.

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New Record of Cantherhines multilineatus (Tanaka, 1918) (Pisces: Monacanthidae) from Jeju Island, Korea (한국 제주도에서 채집된 쥐치과(Monacanthidae) 어류 1미기록종, Cantherhines multilineatus (Tanaka, 1918))

  • Myoung, Se Hun;Kim, Jin-Koo;Kwun, Hyuck Joon
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.51 no.2
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    • pp.199-202
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    • 2018
  • A single specimen (174.5 mm in standard length) of Cantherhines multilineatus, belonging to the family Monacanthidae in the order Tetraodontiformes, was first collected from northern Jeju Island, Korea, in August 2016, using a gill net. This species is distinguished from the congeneric species C. dumerilii by the lack of spines on the sides of its caudal peduncle (vs. two pairs of spines in C. dumerilii) and from C. pardalis in having 9-10 narrow dark longitudinal bands on the cheek and side (vs. dark brown with a network of close-set polygonal spots in C. pardalis). The species also very similar to Stephanolepis cirrhifer, but its first dorsal fin spine is more elongated than the rays of its second dorsal fin rays. We have adopted the Korean common name "Jul-mu-nui-jwi-chi" for C. multilineatus, in accordance with the proposal of Yamada et al. (2009).

A Research of Worker's Uniform in the Mechanical Industry (기계공업 종사자의 작업복 착용 실태조사 연구)

  • 김혜령;서미아
    • The Research Journal of the Costume Culture
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    • v.10 no.6
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    • pp.718-734
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    • 2002
  • The purpose of this study is to provide basic data f3r improvement in Working Uniform in both scientific and efficient ways. The study were enforced by questionnaire and personal interview. The subject of the survey were the workers of 264 in mechanic industry in Seoul. The results obtained from the researches by methods above are as follows. 1. In general, Working Uniform could be classified types of two. One is loose-fitting one-piece garment covering the body and legs, the other is two-piece garment. The latter is a jacket with either sports collar or soutein collar, fastened with either buttons or a zipper and its sleeve is finished by cuffs and tapes. Regarding to color. inkblue, dark navy, khaky, dark beige are favourable ones. 2. In regard to the necessity of uniform that workers suppose, most of them were aware of it and agreed wearing uniform could play an important part. The reason why are on the basis of safety-first and work efficiency and also to protect a body from harmful or toxic dirt specially in machinery workplace. 3. The purpose of wearing an uniform according to statistics of population make some difference in age, gender. categories of industry, and the scale of factory. 4. In regard to care of uniform, front hem, edge of sleeve in a jacket, and knee, hip part in pants were most vulnerable spots for dirt. The parts damaged easily are edge of sleeve in a jacket and a zipper in pants. On the average, laundry have been done by water and was once a week frequency.

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Electroluminescent Characteristics of Fluorescent OLED with Alternating Current Negative Voltage (교류 음 전압에 따른 형광 OLED의 전계 발광 특성)

  • Seo, Jung-Hyun;Yang, Jae-Woong;Paek, Kyeong-Kap;Ju, Sung-Hoo
    • Journal of Surface Science and Engineering
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    • v.52 no.2
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    • pp.72-77
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    • 2019
  • To study the characteristics of AC driven OLED, we fabricated the fluorescent OLEDs and analyzed the electroluminescence characteristics of OLEDs with AC negative voltage. The luminance and the current density of the OLED decreased, and the number and size of the dark spots increased in proportion to the duration time and level of the applied AC negative voltage. The current efficiency of the OLED was improved when high AC negative voltage was applied within a short time. When the AC negative voltage of 10 V was applied for 1 minute, the efficiency was improved by 12.4%. Also, the degradation of luminance and current efficiency due to the duration of light emission was improved in the case of OLED applied for 1 minute with 10 V AC negative voltage. These are expected as a result of the improvement of the leakage current characteristics by eliminating the short-circuit region formed by the defect of the OLED at the AC negative high voltage. As a result, the continuous application of AC negative voltage reduced the luminance and the current density of OLED, but the temporary application of AC negative voltage with the proper time and voltage could improve the efficiency and lifetime of OLED.

Neopestalotiopsis Leaf Blight, an Emerging Concern on Leatherleaf Fern in Indonesia

  • Ani Widiastuti;Indah Khofifah Aruan;Alvina Clara Giovanni;Barokati Tsaniyah;Tri Joko;Achmadi Priyatmojo
    • Research in Plant Disease
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    • v.30 no.1
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    • pp.82-87
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    • 2024
  • Leatherleaf fern (Rumohra adiantiformis) is an important ornamental plant in Indonesia and global. Green fern leaves with bold dark green color with long shelf-life, attract florists as decoration. Indonesia is one important leatherleaf fern exporters, however currently an outbreak of leaf blight decreased production significantly. Initial symptom was reddish brown spots from edge of leaf, which was gradually followed by dark-brown necrotic lesions causing leaf blight and dried. This is a study to do Koch-Postulate approach and molecular identification, to identify the pathogen of the "new emerging disease" reported. Based on multigene analysis using primers from ITS, β-tub and tef1-α gene markers, the pathogen was identified as Neopestalotiopsis sp. All sequences have been deposited in GenBank with accession number of OR905551 (ITS), OR899817 (ßtubulin) and OR899816 (TEF). This Neopestalotiopsis leaf blight causes an emerging concern in leatherleaf fern in Indonesia and global biosecurity because it infected an export commodity.

Changes of Carotenoids of the Pumpkin Powder during Storage (저장중 호박분말의 카로테노이드 색소 변화)

  • 박용곤;강윤한;이병우;석호문
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.26 no.1
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    • pp.32-36
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    • 1997
  • As a fundamental research for the development of pumpkin products, the changes of carotenoids were investigated in hot air dried pumpkin powder packed in PE/nylon film during storage at 2$0^{\circ}C$ under the dark and bright conditions. Total amounts of carotenoids in the dehydrated pumpkin powder were reduced by 65~70 percentage without effect of light after one month. The carotenoids of pumpkin powder were separated to five spots without effect of light by TLC, but difference of color was not significant throughout the storage period. By the analysis of HPLC, leutin, under bright condition, was increased from 15 days of storage but under dark condition it was not changed for one month. Meanwhile, p-carotene, under bright condition, was decreased from 15 days of storage but under drak condition it was decreased from 25 days. The contents of lycopene and $\alpha$ -carotene did not show any significant change throughout the storage period. In color analysis, yellowness value was de- creased in bright as well as dark condition from 10 day storage.

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