• Title/Summary/Keyword: Blue LED

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Reflecting on the History and Future of Republic of Korea Navy (대한민국 해군창설 : 회고와 당부)

  • Hahm, Myung-Soo
    • Strategy21
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    • s.37
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    • pp.5-31
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    • 2015
  • The Republic of Korean Navy (ROKN) started from scratch. However, ROKN demonstrated its Blue Navy capabilities successfully to the entire world by conducting "Operation Early Dawn" at the Aden Bay, Yemen in Jan 2011. On the event of the 70th anniversary of the ROKN, I would like to retrospect past gleaning from voyages and challenges we had in the past. At the very inception of the ROKN, Korean government as well as senior military leaders recognized that it had no time to spare to clean up military those were insinuated deeply by communist agents. It was the top priority of the government. The Mongumpo Operation which was not well known, conducted by ROKN was one of the clean-up drive. The Korean War sometimes called as "a fire from land put-off at the sea". The world famous "Incheon Landing" which reversed war situation from the Nakdong Perimeter also done by Sea Power. ROKN conducted various maritime operations including not only Incheon Landing, but amphibious operation at Hungnam, mine sweeping, sea convoy, Wonsan Withdrawal. On the same day of the Korean War started, 25th June 1950, unless the victory of the ROKNS Baekdusan (PC 701) at the Korean Strait, the waning lamp light of Korea could not be rekindled by the participation of the U.N. The ROKN rescued the 17th regiment of Korean Army from the isolation at the Ongjin Peninsular and transported gold and silver bars stored at the Bank of Korea to the Navy supply deposit in Jinhae safely. ROKN special intelligence unit conducted critical HUMINT which led Incheon Landing success. One of important mission ROKN conducted successfully was not only transporting war fighting materials but also U.S. provided grains to starving Koreans. ROKN participated Vietnam campaign from 1960s and conducted numerous maritime transportation operations supplying materials to Vietnam military forces along the long coastal lines. Experienced Naval Officers and enlisted men who discharged and acquired as merchant marine certificate supported most of the U.S. sea lift operations throughout the Vietnam campaign. ROK-US Combined Forces which had been honed and improved its war fighting capabilities through the Korean War and out of Vietnam jungle playing key deterrent against threat from north Korea. However, those threat level will be completely different when north Korea finish its nuclear weapon ambition. In order to stand firm against north Korean nuclear threat, I would like to expect strong political leadership supporting nuclear submarine for ROKN.

Characteristics of Halophosphate Phosphor for Long-wavelength UV Prepared by Spray Pyrolysis (분무열분해법에 의해 합성된 장파장 자외선용 할로포스페이트계 형광체의 특성)

  • Sohn, Jong-Rak;Kang, Yun-Chan;Park, Hee-Dong;Yoon, Soon-Gil
    • Korean Journal of Materials Research
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    • v.12 no.7
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    • pp.555-559
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    • 2002
  • Blue-emitting $Sr_{10}$($PO$)$_{6}$ $Cl_2$:$Eu^{2+}$ and $_{(Sr,Mg) }$ 10/($PO_4$)$_{6}$ $Cl_2$:$Eu^{2+}$ phosphor particles for application of long-wavelength UV LED were prepared by ultrasonic spray pyrolysis. The luminescence characteristics under long- wave-length ultraviolet of the $Sr_{10}$ ($PO_4$)$_{6}$ $Cl_2$:$Eu^{2+}$ and (Sr,Mg)$_{10}$ ($PO_4$)$_{6}$ $Cl_2$:$^Eu{2+}$ phosphor particles prepared by the spray pyrolysis were compared with that of the commercial product. The PL intensity of the $Sr_{10}$ ($PO_4$)$_{6}$ $Cl_2$:$Eu^{2+}$ particles prepared by the spray pyrolysis was lower than that of the commercial $Sr_{10}$ ($PO_4$)$_{6}$ $Cl_2$:$Eu^{2+}$ particles because prepared $Sr_{10}$ ($PO_4$)$_{6}$ $Cl_2$:$Eu^{2+}$ phosphor particles had porous structure and hollow morphology. However, the PL intensity of the (Sr,Mg)$_{10}$($PO_4$)$_{6}$ $Cl_2$:$Eu^{2+}$ phosphor particles prepared by the spray pyrolysis was 8% higher than that of the commercial one. The high brightness of $(Sr,Mg)_{10}$ ($PO_4$)$_{6}$ $Cl_2$:Eu$^{2+}$ phosphor particles prepared by spray pyrolysis is due to the dense structure and high crystallinity of particles. The TEX>$(Sr,Mg)<_{10}$ ($PO_4$)$_{6}$ /$Cl_2$:$Eu^{ 2+}$ phosphor particles had main emission peak t 448 nm under long- wavelength ultraviolet.

An efficient protocol for the production of transgenic Alstroemeria plants via particle bombardment

  • Kim, Jong Bo
    • Journal of Plant Biotechnology
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    • v.47 no.1
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    • pp.66-72
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    • 2020
  • Alstroemeria plants were transformed by using an improved particle-gun-mediated transformation system. Friable embryogenic callus (FEC) induced from the leaves with axil tissues of Alstroemeria plant was used as the target tissue. Also, FEC was transformed with the bar gene was used as a selectable marker. In the case of plasmid pAHC25, 7.5% of the twice-bombarded FEC clumps showed blue foci, whereas the clumps with single bombardment showed only 2.3%. Additionally, a 90° rotation with double bombardment led to a higher frequency (6 times) of luciferase gene expression in PBL9780 than the control treatment. After 8 weeks of bombardment, more than 60 independent transgenic lines were obtained for pAHC25 and nearly 150 independent transgenic lines were obtained for PBL9780, all of which were resistant to PPT and demonstrated either GUS or luciferase activity. Regarding effect of osmotic treatment (0.2 M mannitol) with 7 different periods, the highest transient gene expression was obtained in 8 h before and 16 h after transformation in both pAHC25 and PBL9780. Compared with the control, at least three times more GUS foci and photons were observed in this treatment. With respect to different combinations of mannitol and sorbitol with 8 h before and 16 h after transformation, high numbers of transient and stable transgene expressions were observed in both 0.2 M mannitol and 0.2 M sorbitol used in the osmotic pre-culture. This combination showed the highest transformation efficiency in both pAHC25 (8.5%) and PBL9780 (14.5%). In the control treatment, only 10% of the FEC clumps produced somatic embryos. However, by using 0.2 M mannitol and 0.2 M sorbitol, the frequency of somatic embryos increased to 36.5% (pAHC25) and 22.9% (PBL9780). Of the somatic embryos produced, at least 60% germinated. Approximately 100 somatic embryos from these 210 independent transgenic lines from 2 plasmids developed into shoots, which were then transferred to the greenhouse. PCR analysis confirmed the presence of the bar gene. This is the report on the production of transgenic Alstroemeria plants by using particle bombardment with a high efficiency, thereby providing a new alternative for the transferring of gene of interests in Alstroemeria in the breeding program in the future.

Optical Simulation Study of the Improvement of Color-rendering Characteristics of White Light-emitting Diodes by Using Red Quantum-dot Films (적색 양자점 필름을 이용한 백색 발광 다이오드의 연색성 개선에 대한 광학 시뮬레이션 연구)

  • Lee, Gi Jung;Hong, Seung Chan;Lee, Jung-Gyun;Ko, Jae-Hyeon
    • Korean Journal of Optics and Photonics
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    • v.32 no.4
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    • pp.163-171
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    • 2021
  • Conventional white light-emitting diodes (LEDs) for lighting applications consist of blue LEDs and yellow phosphors, the spectrum of which lacks deep red. To improve the color-rendering characteristics of white LEDs, a red quantum-dot film was applied to the diffuser plate of LED lighting. The mean free paths of the quantum dots and the concentration of the TiO2 particles in the diffuser plate were adjusted to optimize the optical structure of the lighting. The color-rendering index (CRI) was greater than 90 for most conditions, which demonstrates that adoption of the red quantum-dot film is an effective way for improving the color-rendering properties of conventional white LEDs. The angular dispersion of color coordinates could be removed by utilizing the optical cavity formed between the diffuser plate and the reflector on the bottom of the lighting, where multiple passages of the light through the quantum-dot film reduced the differences in optical path length depending on the viewing angle.

Effect of the Multisensory on the Stress-relieving for Vehicle Driver (운전자 스트레스 저감을 위한 다감각 자극의 효과)

  • Kim, Young-Joo;Kim, Hyejin;Lee, Hyunwoo;Jo, Youngho;Whang, Mincheol
    • Science of Emotion and Sensibility
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    • v.24 no.4
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    • pp.107-116
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    • 2021
  • This study aims to investigate the effect of multisensory stimulation on relieving the stress experienced by drivers. The photoplethysmograms (PPGs) of 30 healthy subjects were measured, and their subjective response to stressful situations and normal driving were evaluated. The subjects underwent nonstimulation and multisensory stimulation in stressful driving situations. Heart rate estimation from the PPG was collected via an ear-type sensor to reduce movement noise. The signals acquired were sampled at 200 Hz using BIOPAC PPG100C. Heart rate variability (HRV) was analyzed to compare the effect of multisensory stimulation on stress situations. In the multisensory stimulation, blue, green, and yellow were used for the visual sensory system; white, pink, and brown noises were used for the auditory sensory system; and lavender, lemon, and rosemary were used for the olfactory sensory system. No difference was observed in the subjective evaluation; however, the HRV results showed an increased HF (%) and decreased LF (%) and LF/HF (%) in the multisensory stimulation (e.g., green, pink noise, and rosemary) when compared to the nonstimulation.

Synthesis and photoluminescence characteristics of SrAl2O4:Mn4+ phosphor for LED applications (LED용 SrAl2O4:Mn4+ 형광체 합성 및 발광특성 연구)

  • Byoung Su Choi;Jun Ho Lee;Sungu Hwang;Jin Kon Kim;Byeong Woo Lee;Hyun Cho
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.33 no.1
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    • pp.1-16
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    • 2023
  • A non-rare earth-based strontium-aluminate red light emitting phosphor was synthesized by a solid-state reaction method and the effect of synthesis temperature and Mn4+ activator concentration on the photoluminescence characteristics of the phosphor was studied. The synthesized SrAl2O4:Mn4+ phosphor showed broad band absorption characteristics in the near-ultraviolet and blue regions with peaks at wavelengths of near 330 and 460 nm, and a triple band deep red emission consisted of three peaks at near 644, 658, and 673 nm. The SrAl2O4:Mn4+ phosphor synthesized at a temperature 1600℃ and a Mn4+ activator concentration of 0.5 mol% showed the strongest PL emission intensity, and concentration quenching was observed at concentrations higher than 0.7 mol%. FE-SEM and DLS particle size distribution analysis showed that the synthesized SrAl2O4:Mn4+ phosphor had a particle size distribution of 2~6.4 ㎛ and an irregular spherical shape with an average particle size of ~4 ㎛.

Growth of Kale Seedlings Affected by the Control of Light Quality and Intensity under Smart Greenhouse Conditions with Artificial Lights (인공광 스마트온실에서 광질 및 광강도 제어가 케일 실생묘의 생장에 미치는 영향)

  • Heo, Jeong-Wook;Lee, Jae-Su;Lee, Gong-In;Kim, Hyun-Hwan
    • Korean Journal of Environmental Agriculture
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    • v.36 no.3
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    • pp.193-200
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    • 2017
  • BACKGROUND: Plant growth under smart greenhouse (that is plant factory system) conditions of an artificial light type is significantly depending on the artificial light sources such as a fluorescent lamps or Light-Emitting Diodes (LEDs) with specific spectral wavelengths regardless of the outside environmental changes. In this experiment, characteristics on the growth and compound synthesis of kale seedlings affected by light qualities and intensities provided by LEDs were mentioned. METHODS AND RESULTS: The kale seedlings which developed 3~4 true leaves were exposed by fluorescent lamps or LEDs lights of red (R), blue+white (BW), blue+red (BR) with 50 (L) or $100(H){\mu}mol/m^2/s^1$ photosynthetic photon flux (PPF) under hydroponic culture system of deep flow technique for 50 days. Shoot fresh weight increased under the RH, BWH, and BRH treatments with higher PPF. Shoot elongation of the seedlings decreased, and polyphenol synthesis promoted by the higher light intensity conditions. Sugar synthesis in the leaves was above 2 times greater under the RH treatment of monochromic red light quality with $100{\mu}mol/m^2/s^1\;PPF$ than $50{\mu}mol/m^2/s^1\;PPF$. CONCLUSION: The results show that the control of light quality and intensity in the smart greenhouse conditions with artificial lights significantly affects the growth and compound synthesis in the fresh kale leaves with higher culture efficiency compared to the conventional soil culture under greenhouse or field conditions. Researches on the optimum light intensities of the LEDs with special spectral wavelengths are necessary for maximum growth and metabolism in the seedlings.

A study of Symbolics of Chinese Liturgical Vestments (중국 제복의 상징성에 관한 연구)

  • 이선희
    • Journal of the Korean Society of Costume
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    • v.18
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    • pp.111-131
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    • 1992
  • This thesis was designed to study Symbolics of Chinese Liturgical Vestments. Chinese who regarded the life of human beings as the combination of heaven and earth considered garments as the traditional product of the movement of nature. Accordingly, they thought human beings are the center of the universe composed by heaven and earth and the chief of all things; therefore man only can utilize clothes to distinguish from all of the colours. This views of clothes led to the development of liturgical vestments esteemed courtesy than anything else, especially the thought of courtesy associated with Conficius who regarded courtesy as the highest things and since then the theory of Five Elements and courtesy were inherited by all the adherents of Conficius. Yin and Yang Five Elements in the liturgical vestments was given absolute symbolics in both formative side and in colourful side. results of research studied in this was can be summed up as follows : 1. The crown of rites was made imitating after the system of head, horn, beard, bread of birds and beasts and that form of crown is front-circ-ular and back-rectangular meant to be towards light and dark. That the upper part of faceplace is black represented the way of heaven and lower part of red symbolized the way of earth. 2. Upper vestment of liturgical rites symbolizes heaven and outskirt represented earth. So front of outskirt is YANG and back is Yin. It is why then are going to harmonize positive and negative making front part three width and back part four width. Therefore, emperor who symbolizes heaven made the subjects recognize high and low and wore Dae-gu(大 ), Kon-bok(袞服), Bel-bok, Chui-bok, and Hyonbok according to the object and position of rites so that he may rule the country based on courtesy. 3. As an accessory of liturgical vestments, Bul, Pae-ok, Su, Dae-dai, Hyok-Dai, Kyu, and Hol were used. Before Bul was used man dressed skirt as the first waist-dress in order to conceal intimate part of the body. Pae-ok, as decoration blended with jade was worn by men of virtue, so men of virtue symbolized morality and virtue by Pae-ok. Su began from Yeok, connected with Pae-su , in Chou-dynasty is said to be originated by practical needs and they are divided into large Su and small su, and maintained as decoration to signify the class positions. Dae-dai did the work as not to loose the liturgical vestments and leather belt hang Bul and Su to begin as the function of practical use are in later years it became decoration to symboliz e the class position. Kyu was a jade used when empeor nominated feudal lords and observe ceremony to God and Hol, was held in hands to record everything not to forget. These Kyu and Hol became to offer courtesy during the time of rites and in later years it became used according to class position rather than practical use. 4. As far as colours are concerned, colours based by five colours according to YIN-YANG Five Elements theory and they were divided into a primary colour and a secondary colours. Primary colours corresponded with the theory of Five Elements each other, Blue, Red, Tellow, White, and Black symbolized ive Elements, five hour space, five directions, and five emperors. Secondary colours contradict with Blue, Red, Yellow, White and Black and another as a primary colour and they are Green, Scaret, Indigo, Violet, Hun colour, Chu colour, and Chi colour. This primary colour was used in liturgical vestments, that is, upper-vestments used black colour. This primary colour was used in liturgical vestments, that is, upper-vestments used black colour as primary colour and outskirt was used Hun colour as secondary colours. Thus symbolism in chinese liturgical vestments mainly began with heaven and earth and corresponded with YIN-YANG Five Elements Scool. They were developed as the scholary theory and Conficius and his followers in the later days and continued up to Min-dynasty.

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A Diachronic Study on Historical and Cultural Landscape of Songhyeon-dong, Seoul (서울 송현동(松峴洞) 일원 역사문화경관의 통시적 연구)

  • Kang, Jae-Ung;So, Hyun-Su
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.39 no.4
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    • pp.85-98
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    • 2021
  • In accordance with planning to construct culture park on Songhyeon-dong (district) near Gyeongbokgung Palace, This study analyzed literature and drawings from the early Joseon Dynasty to today for the district, known as 'Songhyeon (pine hill)' to identify historical and cultural landscapes during essential times. The following are the results; First, the owners of significant lots were identified, and land use and landscape components were extracted for a diachronic examination of the landscape of the whole area of Songhyeon-dong. Songhyeon district had been regarded as the 'Inner Blue Dragon (Spot) of Gyeongbokgung Palace' in terms of geomancy since the foundation of Joseon in 1392 in that the government created and managed a 'pine forest' in the district. A state warehouse called 'bungam' was constructed, and small fruit stores, 'ujeon,' opened due to the complete reformation and urban planning led by King Taejong in 1410. From the 19th century, mansions of the upper class, such as 'Gaseonggak', 'Changnyeongwuigung' and 'Byeoksugeosajeong' were in the district. A prominent official residential complex called 'Sigeun Sataek' was constructed in 1919 after Chosen Siksan Bank purchased the site. Later, it was transferred to America in 1948 and used as the 'US Embassy Staff Quarters'. Second, the changes in the site view, associated with the aspects of society by the times, were examined by estimating the location and the time the landscape components lasted in each period extracted and identifying the physical entity. The pine forest, regarded as the 'Inner Blue Dragon' that guards the left side of the palace within the geomantic world view, was located in the highlands in the west of the site. In the same period, the flat area in the east was regarded as the 'commoner's district', the streets adjacent to various government facilities and the market, packed with people from different walks of life. From the 19th century, the gardens of the aristocrats of the capital city were created in the pine forest, turning the place into the forest in the middle of the city. The whole area of Songhyeon-dong, which existed as a large lot in the city center for a long time, was developed by Japanese imperialists in the 20th century based on the concept of 'Ideal Healthy Land,' which interrupted the placeness of Songhyeon-dong that had adhered to the traditional geomatic view of the Joseon Dynasty.

Classification of Carbon-Based Global Marine Eco-Provinces Using Remote Sensing Data and K-Means Clustering (K-Means Clustering 기법과 원격탐사 자료를 활용한 탄소기반 글로벌 해양 생태구역 분류)

  • Young Jun Kim;Dukwon Bae;Jungho Im ;Sihun Jung;Minki Choo;Daehyeon Han
    • Korean Journal of Remote Sensing
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    • v.39 no.5_3
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    • pp.1043-1060
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    • 2023
  • An acceleration of climate change in recent years has led to increased attention towards 'blue carbon' which refers to the carbon captured by the ocean. However, our comprehension of marine ecosystems is still incomplete. This study classified and analyzed global marine eco-provinces using k-means clustering considering carbon cycling. We utilized five input variables during the past 20 years (2001-2020): Carbon-based Productivity Model (CbPM) Net Primary Production (NPP), particulate inorganic and organic carbon (PIC and POC), sea surface salinity (SSS), and sea surface temperature (SST). A total of nine eco-provinces were classified through an optimization process, and the spatial distribution and environmental characteristics of each province were analyzed. Among them, five provinces showed characteristics of open oceans, while four provinces reflected characteristics of coastal and high-latitude regions. Furthermore, a qualitative comparison was conducted with previous studies regarding marine ecological zones to provide a detailed analysis of the features of nine eco-provinces considering carbon cycling. Finally, we examined the changes in nine eco-provinces for four periods in the past (2001-2005, 2006-2010, 2011-2015, and 2016-2020). Rapid changes in coastal ecosystems were observed, and especially, significant decreases in the eco-provinces having higher productivity by large freshwater inflow were identified. Our findings can serve as valuable reference material for marine ecosystem classification and coastal management, with consideration of carbon cycling and ongoing climate changes. The findings can also be employed in the development of guidelines for the systematic management of vulnerable coastal regions to climate change.