• Title/Summary/Keyword: dark spot

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A taxonomic Revision of Genus Carcharhinus (Pisces: Elasmobranchii) with Description of Two New Recrods in Korea (한국산 흉상어속 어류의 분류학적 재검토 및 2미기록종)

  • Youn Choi;Ik-Soo Kim;Kazuhiro Nakaya
    • Animal Systematics, Evolution and Diversity
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    • v.14 no.1
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    • pp.43-49
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    • 1998
  • The taxonomic revision of the genus Carcharhinus in Korea was made based on the shark specimens collected in the western and southern coasts including Cheju Isl. of Korea from July 1996 to April 1997. Five species were recognized from the Korean waters and they are described herein. Among them, two species of Carcharhinus dussumieri (Valenciennes, 1839) and Carcharhinus sorrah (Valenciennes, 1839) were collected for the first time from the Cheju Isl. coast of Korea. Carcharhinus dussumieri differs from other species of genus Carcharhinus in following morphological characters: a black or dark spot on the sencond dorsal fin but no other markings, a small first triangular dorsal fin and a second dorsal fin with a short inner margin, and Carcharhinus sorrah: conspicuous black tips on the ventral caudal lobe, pectoral and second dorsal fins, and low second dorsal with a inner margin.

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Studies on quality control of domestic Morus alba Linne (국내산 상지(桑枝)의 품질관리 연구)

  • Park, Yu Mi;Beak, Mi Eun;Lee, Young Jong;Won, Jae Hee
    • The Korea Journal of Herbology
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    • v.31 no.3
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    • pp.71-75
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    • 2016
  • Objectives : Mori Ramulus is a young branch of Morus alba Linne, which has been used as traditional medicines for antidiarrhea, antibacteria, and antihypertension in Korea. With the basis on these medicinal activities, it is registered at the Korean Herbal Pharmacopoeia. The standard for quality control in use, however, is not yet validated.Methods : We experiment on heavy metals test, TLC, loss on drying, ash, acid-insoluble ash, contents of ethanolsoluble extracts and contents of oxyresveratrol by using the 15 samples of Mori Ramulus which are collected domestically. We tested items according to the General Test, processes and apparatus, Crude Drugs Test of KP(2011).Results : Purity test(Heavy metals) showed contents for Pb, As, Hg, and Cd range of 0.1~1.1 ppm, 0.0~0.2 ppm, 0.00~0.01 ppm, and 0.00~0.02 ppm. Identification test(Thin layer chromatography) was on comparing with morucine standard solution in Rf value, all samples showed morucine spot (dark blue, Rf : 0.3) as same as Rf value of morucine-standard solution. Loss on drying was ranged from 5.1 to 8.9 %, ash and acid-insoluble ash were between the range 3.0~6.3% and 0.3~0.8%. Contents of ethanol-soluble extracts was ranged from 6.2 to 12.0%. Content of oxyresveratrol was ranged from 0.01 to 0.16 % based on the oxyresveratrol standard curve.Conclusions : We sincerely hope that this study will be contributed to the standardization and quality control of Korean herbal medicines.

The Occurrence of Strawberry Black Leaf Spot Caused by Alternaria alternate (Fr.) Keissler in Korea (딸기 검은무늬병(Alternaria alternata (Fr.) Keissler)의 발생에 관하여)

  • Cho J.T.;Moon B.J.
    • Korean journal of applied entomology
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    • v.19 no.4 s.45
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    • pp.221-227
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    • 1980
  • A new disease of strawberry caused by Alternaria was found in Gim Hae, Gyougnam province, in July 1979. The symptoms of the disease occurred mainly on leaves as showing dark brown spots with circular to irregular, $5\~6mm$ in diameter. The pathogen was identified as Alternaria alternate (Fr.) Keissler which has not been described in Korea as a pathogen of strawberry disease. The common name of the disease was given as Gum un mum byung of strawberry. The conidia shape and size of this fungus varied considerably with culture media. The measurements of conidia and beak on corn meal agar were $20.1\times9.3{\mu}\;and\;4.0\mu$, respectively, which were shorter than those on strawberry leaf lesions in the field. Among 49 strawberry varieties tested, Morioca 16 and Robinson were highly susceptible to the disease by artificial inoculation and Catskill, Cyclone, Northwest, Merton princess, Juspa and Daehak I were moderately susceptible whereas 31 varieties were resistant. This fungus could also infect the leaf of Common garden sunflower, Double sunflower and Mexican sunflower among the 14 plants species tested.

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A Study on the State of Clothing Habits of Yanbian Chinese-Koreans - Focusing on the Girl College Students and the Housewives in the Yangil City - (연조(延朝) 조선족(朝鮮族)의 의생활(衣生活) 실태(實態)에 관(關)한 연구(硏究) - 연길시(延吉市) 여대생(女大生)과 주부(主婦)를 중심(中心)으로 -)

  • Cho, Kyu-Hwa;Lee, Hee-Seung
    • Journal of Fashion Business
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    • v.5 no.1
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    • pp.1-15
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    • 2001
  • The purpose on this study is to grasp the clothing habits and problems of the Chinese-Koreans in Yanbian, China through the fact-finding survey about the clothing habits for the Chinese-Koreans in Yanbian, China who have frequent exchanges with the North Korea and have relatively similar home culture preparing for the unification of North and South Korea, also it is to make the basic data for improving their qualities of life. As for the method of study, it centered on the investigation by the questionnaire on the spot and it referred to the data like domestic and abroad literature, field observation, interview and internet, etc. as a reference. Also it centered on the girl college students and the housewives in Yangil City as an object of research. Accordingly, the result of this study is as follows. The Yanbian is the largest Chinese-Koreans group of people in the China. The economic environment in Yanbian is in the middle of the whole China. With the open-economy of China and the contact with the foreign culture, especially with Korea, the 1960s and 1990s coexist in. The Chinese-Koreans in Yangil spend about 1,425 CNY as clothing expenses averages a year, and the estimated value of holding amount of clothing is about 27 suits. They recognize the clothing made in Korea as high-quality and high-price of high-quality articles. They have high interest in the Korean fashion as the younger generation. They prefer to modern, active, refined and mature atmosphere in the clothing atmosphere, but they still do not reach to the level yet in actual. They generally have strong tendency with the preference of black color or dark color because they have small holding amount. The field materials of fiber did not become high-quality articles because they hold in the level of 1960s in Korea. So, the color level of Chinese-Koreans in Yanbian is still low.

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Stem Rot of Hosta longipes Caused by Sclerotium rolfsii in Korea (Sclerotium rolfsii에 의한 비비추 흰비단병)

  • Kwon Jin-Hyeuk;Park Chang-Seuk
    • Research in Plant Disease
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    • v.11 no.2
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    • pp.201-203
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    • 2005
  • The stem rot disease was found on Hosta longipes that planted in the flower beds along the Namgang riverside in Jinju city, Korea. The disease occurred first time in July, 2004 and sporadically occurred in 2005. The typical symptom of the disease is water-soaking, dark brown spot on the stem, and getting wilt. The infected plants were mostly died. White mycelial mats were spread over lesions and sclerotia were formed on stems and near soil line. The sclerotia were globoid in shape, $1\~3$ mm in diameter and white to brown in color, The optimum temperature for mycelial growth of the fungus on PDA was $30^{\circ}C$ and the hyphal width was $4\~8{\mu}m$. Clamp connections were observed in the hyphae of the fungus grown on PDA. Pathogenicity of the causal organism was proved on Hosta longipes according to Koch,s postulate. On the basis of mycological characteristics and pathogenicity to host plants, the fungus was identified as Sclerotium rolfsii Saccardo. This is the first report on the stem rot of H. longipes caused by S. rolfsii in Korea.

Sooty Leaf Blight of Cymbidium spp. Caused by Pseudocercospora cymbidiicola (Pseudocercospora cymbidiicola에 의한 심비디움 검은잎마름병)

  • Han, Kyung-Sook;Park, Jong-Han;Lee, Jung-Sup;Cheong, Seung-Ryong
    • Research in Plant Disease
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    • v.13 no.2
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    • pp.126-129
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    • 2007
  • Sooty leaf blight disease of Cymbium spp. was observed on orchid fields located at Gyeonggi-do in 2005-2006. Symptoms of the disease appeared on leaves and leaf spots were circular to nearly-circular, these circular blemished were yellow, with greater amounts of brown to black flecks forming as the spots enlarge. Severely infected leaves were dry and defoliated. These symptoms were realized wrongly as symptoms by virus. But Pseudocercospora cymbidiicola were isolated from the diseased plants. Conidiophores were produced on the lesion surface of the leaf with the blemished areas andconidia formed dark brown, cylindrical and straight to slightly curved, 5-9 septate, $23.7-85.0\;{\times}\;2.0-3.4\;{\mu}m$. Mycelial growth was mostly slow on potato dextrose agar and the optimum temperature for growth was $25^{\circ}C$. We were identified as Pseudocercoepora cymbidiicola based on the morphological characteristics.

Ecology and Early Growth of Monostroma nitidum (Ulvales, Chlorophyta) in Korea (녹조류 참홑파래 (Monostromu nitidum)의 생태와 초기생장)

  • Yoon, Jang-Taek;Cho, Yong-Chul;Gong, Yong-Gun;Chung, Gyu-Hwa
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.39 no.5
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    • pp.419-426
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    • 2006
  • This study investigated the ecology and growth of Monostroma nitidum Wittrock in both its natural habitat and the laboratory. The maximum length, width, and weight of M. nitidum in March were 9.0$\pm$4.7 cm, 9.6$\pm$3.6 cm, and 1.52$\pm$1.13 g, respectively. Yellowish-green or yellowish-brown reproductive thalli began to appear in January, and over 80% of the thalli matured by March. The male and female spores were ca. 6 $\mu$m long, and elongate and ovoid in shape. The spores had two flagella and one-eye spot, and tended to swim toward light. Maximum number of spores released from matured thalli was 236 cells/mL after 70 minutes at a light intensity of 100 $\mu$mol/m$^2$/s. The zygote diameter ranged from 3.4-6.0 $\mu$m (mean 4.2 $$m) and increased to 69.8 $\mu$m 14 weeks after culture. The mass release of zoospores was observed from thalli in the dark (3 to 12 days), after 30 min under dry conditions in the shade, at 25$^{\circ}C$, and a light intensity of 100 $\mu$mol/m$^2$/s. The maximum number of zoospores released was 109.8 cells/mL after 60 min of induction. M. nitidum fronds on the net increased to 6.8-7.2 cm in length, and 6.6-8.9 cm in width during the winter.

Pro-environmental Maintenance and Management of Tour Cave : The Currents, Problems and Alternatives in Korea (관광동굴의 환경친화적 관리 방안에 관한 연구)

  • 유영준;이경호
    • Journal of the Speleological Society of Korea
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    • v.59
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    • pp.21-36
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    • 1999
  • Most scholars calssify caves into natural resource, but caves possess values of natural and human resource, mix up the features of natural resources and human resources. Now, caves are distributed 260 in Korea. Seongryu Cave is showed in 1967 for the first time, till 1997 12 caves is opened to tourist. But since 1996 the 12 show caves of all is not launched the safety and environment-protection check-up adduced reason for IMF. Then caves must maintain environment of the normal temperature, humidity and dark. But the environment of caves are destroyed by tourism development. Thus to maintain environment of caves, it used to consider the counterplan as follows in restraint of the environmental change. Firstly, in case of development work to open caves, it must keep up with the prototype. Secondly, it must establish a freight depositary to prevent the influence of the caves's stain and damage due to tourist's objects. Thirdly, to maintain the normal temperature and humidity, it must install artificial poultice equipment of the inner parts of caves. Fourthly, in order to prevent the occurrence of $CO_2$, it must assessment of the optimum number of the greatest stayer. Fifthly, the control of closure for a given period of time is useful of the restoration to the cave's original state. Sixthly, by means of make narrow entrance, it should not influence the outer's air on the inner parts on caves. Seventhly, to keep the temperature of the inner part of caves, the lightening should be maintained moderately considering the convenience of a tour. Eightly, when water-proof cables for the lightening bulbs are connected each other, silicon tape is suitable and circuit breakers should be installed at the diverging points of the cables. Ninthly, the direction and angle of the lightening must be changed periodically to prevent green-pollution at the lightening spot. Lastly, when facilities and arrangements are equipped, corrosive materials should be excluded if circumstances allow.

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Properties of Defective Regions Observed by Photoluminescence Imaging for GaN-Based Light-Emitting Diode Epi-Wafers

  • Kim, Jongseok;Kim, HyungTae;Kim, Seungtaek;Jeong, Hoon;Cho, In-Sung;Noh, Min Soo;Jung, Hyundon;Jin, Kyung Chan
    • Journal of the Optical Society of Korea
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    • v.19 no.6
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    • pp.687-694
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    • 2015
  • A photoluminescence (PL) imaging method using a vision camera was employed to inspect InGaN/GaN quantum-well light-emitting diode (LED) epi-wafers. The PL image revealed dark spot defective regions (DSDRs) as well as a spatial map of integrated PL intensity of the epi-wafer. The Shockley-Read-Hall (SRH) nonradiative recombination coefficient increased with the size of the DSDRs. The high nonradiative recombination rates of the DSDRs resulted in degradation of the optical properties of the LED chips fabricated at the defective regions. Abnormal current-voltage characteristics with large forward leakages were also observed for LED chips with DSDRs, which could be due to parallel resistances bypassing the junction and/or tunneling through defects in the active region. It was found that the SRH nonradiative recombination process was dominant in the voltage range where the forward leakage by tunneling was observed. The results indicated that the DSDRs observed by PL imaging of LED epi-wafers were high density SRH nonradiative recombination centers which could affect the optical and electrical properties of the LED chips, and PL imaging can be an inspection method for evaluation of the epi-wafers and estimation of properties of the LED chips before fabrication.

Dynamic properties of the retinal neurons by using of the intracellular recording method (세포내 기록법으로써 검출한 망막 신경원의 동적 특성)

  • 이성종;정창섭;배선호
    • Progress in Medical Physics
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    • v.9 no.2
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    • pp.95-104
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    • 1998
  • The dynamic properties of the 3rd-order neuron of the retina was investigated by using conventional intracellular recording techniques. Experiments were performed in the superfused retina-eyecup preparation of the channel catfish, Ictalurus punctatus. The cornea, iris, lens, and vitreous were removed by absorption with Kimwipe tissue under the dissection microscope thereby exposing the retina in a hemi -eyecup. The electrical signal was amplified by electrometer, viewed on oscilloscope. Regular signals from the cells were recorded on a penwriter and stored by data recorder and computer. Full-field, spot or annular light stimuli were generated on a computer monitor and focused onto the retina. Baclofen hyperpolarized the dark membrane potential, suppressed sustained component and enhanced transient component of the ON-sustained cell with a large transient component, but did not affect the surround antagonism of the cell. Baclofen selectively suppressed responses evoked by moving bar light stimuli on the ON-OFF transient cell. The results suggest that transient cells have directional selectivity in the inner retina. These dynamic properties of amacrine and ganglion cells were modulated by baclofen. Therefore, it is presumed that there is baclofen-induced directional selectivity in ON-OFF transient cells in the catfish retina.

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