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Excimer-Based White Phosphorescent OLEDs with High Efficiency

  • Yang, Xiaohui;Wang, Zixing;Madakuni, Sijesh;Li, Jian;Jabbour, Ghassan E.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.1520-1521
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    • 2008
  • There are several ways to demonstrate white organic light emitting diodes (OLEDs) for displays and solid state lighting applications. Among these approaches are the stacked three primary or two complementary colors light-emitting layers, multiple-doped emissive layer, and excimer and exciplex emission [1-10]. We report on white phosphorescent excimer devices by using two light emitting materials based on platinum complexes. These devices showed a peak EQE of 15.7%, with an EQE of 14.5% (17 lm/W) at $500\;cd/m^2$, and a noticeable improvement in both the CIE coordinates (0.381, 0.401) and CRI (81). Devices with the structure ITO/PEDOT:PSS/TCTA (30 nm)/26 mCPy: 12% FPt (10 nm) /26 mCPy: 2% Pt-4 (15 nm)/BCP (40 nm)/CsF/Al [device 1], ITO/PEDOT:PSS/TCTA (30 nm)/26 mCPy: 2% Pt-4 (15 nm)/26 mCPy: 12% FPt (10 nm)/BCP (40 nm)/CsF/Al [device 2], and ITO/PEDOT:PSS/TCTA (30 nm)/26 mCPy: 2% Pt-4: 12% FPt (25 nm)/BCP (40 nm)/CsF/Al [device 3] were fabricated. In these cases, the emissive layer was either the double-layer of 26 mCPy:12% FPt and 15 nm 26 mCPy: 2% Pt-4, or the single layer of 26mCPy with simultaneous doping of Pt-4 and FPt. Device characterization indicates that the CIE coordinates/CRI of device 2 were (0.341, 0.394)/75, (0.295, 0.365)/70 at 5 V and 7 V, respectively. Significant change in EL spectra with the drive voltage was observed for device 2 indicating a shift in the carrier recombination zone, while relatively stable EL spectra was observed for device 1. This indicates a better charge trapping in Pt-4 doped layers [10]. On the other hand, device 3 having a single light-emitting layer (doped simultaneously) emitted a board spectrum combining emission from the Pt-4 monomer and FPt excimer. Moreover, excellent color stability independent of the drive voltage was observed in this case. The CIE coordinates/CRI at 4 V ($40\;cd/m^2$) and 7 V ($7100\;cd/m^2$) were (0.441, 0.421)/83 and (0.440, 0.427)/81, respectively. A balance in the EL spectra can be further obtained by lowering the doping ratio of FPt. In this regard, devices with FPt concentration of 8% (denoted as device 4) were fabricated and characterized. A shift in the CIE coordinates of device 4 from (0.441, 0.421) to (0.382, 0.401) was observed due to an increase in the emission intensity ratio of Pt-4 monomer to FPt excimer. It is worth noting that the CRI values remained above 80 for such device structure. Moreover, a noticeable stability in the EL spectra with respect to changing bias voltage was measured indicating a uniform region for exciton formation. A summary of device characteristics for all cases discussed above is shown in table 1. The forward light output in each case is approximately $500\;cd/m^2$. Other parameters listed are driving voltage (Bias), current density (J), external quantum efficiency (EQE), power efficiency (P.E.), luminous efficiency (cd/A), and CIE coordinates. To conclude, a highly efficient white phosphorescent excimer-based OLEDs made with two light-emitting platinum complexes and having a simple structure showed improved EL characteristics and color properties. The EQE of these devices at $500\;cd/m^2$ is 14.5% with a corresponding power efficiency of 17 lm/W, CIE coordinates of (0.382, 0.401), and CRI of 81.

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A Study on the Diffusion Factor of e-finance (e-Finance의 확산요인에 관한 연구)

  • Kim, Min-Ho;Song, Chae-Hun;Song, Sun-Yok;Cha, Sun-Kwon
    • International Commerce and Information Review
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    • v.4 no.2
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    • pp.253-277
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    • 2002
  • Nowaday, the advanced technology in information and communication has been leading the dramatic change of transaction paradigm expansion from physical basis to electronic one. As we know, financial services support most of financial exchange between two business parties. So the expansion of electronic transaction paradigm affects to every financial institutions which provide financial services. Thus, financial institutions have accepted e-Finance systems and providing internet financial services to live in the competition. The purpose of this study is to contribute the qualitative enhancement of its customer service, rapid diffusion and accurate strategy establishment for e-Finance industry in the user side. Through the literature review and factor and reliability analysis, this study selects six diffusion factors such as efficiency of perceived e-Finance, reliability and safety of e-Finance in perceived e-Finance itself's characteristic; confidence, technical factors and the customer service quality of e-Finance system in perception on e-Finance System; inclination to innovation in the personal characteristic. According to result of hypothesis verification by using logistics regression analysis, technical factors and the customer service quality of e-Finance system in perception on e-Finance System and inclination to innovation in the personal characteristic gave statistically positive effect to the diffusion decision at the significant level 0.05 and 0.01. However efficiency of perceived e-Finance, reliability and safety of e-Finance in perceived e-Finance itself's characteristic didn't affect to diffusion decision and confidence of e-Finance system in perception on e-Finance System didn't have any statistical significancy. This study can be used as a basic material for the forward empirical study of diffusion factors in the user side and be able to apply to company and government policy making or embodiment, determination for customer service quality degree of financial institutions. But this study has some limitations like didn't touch satisfaction factors and its effect, only deal domestic customers and didn't use multi-regression analysis.

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A STUDY ON SKELETAL RELAPSE PATTERNS FOLLOWING ORTHOGNATHIC SURGERY OF CLASS III PATIENTS : COMPARISON BETWEEN SSRO AND IVRO (제 III급 부정교합자의 악교정 수술후 골격적 재발 양상에 관한 연구 : 구내 시상 분할 골절단술과 구내 상행지 수직 골절단술의 비교)

  • Lee, Jang-Yeol;Yu, Hyung-Seog;Ryu, Young-Kyu
    • The korean journal of orthodontics
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    • v.28 no.3 s.68
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    • pp.461-477
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    • 1998
  • To evaluate the relapse pattern and long-term stabilities depanding on surgical methods following orthognathic surgery of Cl III patients, the author selected 24 subjects(10 male, 14 female) operated by SSRO and 26 subjects(10 male,16 female) operated by IVRO. Each subject took four lateral cephalograms : just before surgery(T1), within 48hrs after surgery(T2), 4-8 wks after surgery(T3), 6 month or more after surgery(T4), and the landmarks were digitized. The differences of relapse patterns in each interval between two groups were compared and the significance of correlation among the variables of each group was tested. The obtained results are as follows ; 1. Horizontal early relapse was forward movement of mandible in SSRO group, as compared to the backward movement in IVRO group, and there was a statistical significance between the two groups. 2. Vertical early and late relapses were decreases in anterior facial height in both groups and there was no statistical significance between the two groups. 3. There was a statistical significance in negative correlation between mandibular horizontal late relapse and surgical change of articular angle in SSRO group. 4. There was a statistical significance in negative correlation between amount of mandibular set-back and mandibular horizontal early relapse in both groups.

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Comparative Evaluation of Neighborhood Parks in Korea and China based on the Place Attachment Model (장소애착 모델에 근거한 한국·중국 근린공원의 비교평가)

  • Yang, Lei;Lee, Shiyoung
    • Journal of the Korean Institute of Landscape Architecture
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    • v.45 no.3
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    • pp.21-29
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    • 2017
  • In this study of visitor place attachment to parks, Scannel and Gilford considered the dimensions of place attachment, and proposed the theoretical framework of PPP(Place, Person, Process) that should be systematically studied from the perspective of person, place and psychological processes. According to Scannel's theoretical basis, this paper puts forward the hypothesis of a structure model of place attachment. In the model, the five independent variables of people, places, cognition, emotion, and behavior have influenced the dependent variable of place attachment. The questionnaire was conducted on 18 neighborhood parks in Kunming, China, and the residents of the 5 neighborhood parks in Daejeon, South Korea. A total of 1,645 valid samples of the questionnaire survey were collected. Through confirmatory factor analysis(CFA) results of the inspection of the various elements, it was shown that the reliabilities of 6 latent variables, such as people, places, cognition, affection, behavior and place attachment, which were composed with the observed variables(30 observed variables in Daejeon, 19 observed variables in Kunming), were all above 0.7 and the data were fit for this study. The hypothesis test results found that the physical environment of the neighborhood parks such as a comfortable environment, pleasant road and convenient facilities would increase the rate of visitors coming back. From the park management perspective, to increase the amount of visitors to the park, the park should increase visibility, provide more organized, varied activities and meetings, or special exhibitions according to the particular characteristics of the individual park, to increase awareness of the park. From the park visitors' psychological perspective, visitors are seeking to enjoy the park facilities and environment not only to bring physical relaxation, but also to bring about a psychological cure. With the commonality of attachment structure between the two countries, to improve the place attachment of neighborhood park visitors, collecting regularly visitor feedback will facilitate the sustainable development of neighborhood park attachment.

ATTACHMENT AND PSYCHOPATHOLOGY (애착과 정신병리)

  • Choi, Jee-Eun;Ahn, Dong-Hyun
    • Journal of the Korean Academy of Child and Adolescent Psychiatry
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    • v.15 no.1
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    • pp.40-60
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    • 2004
  • Introduction:Research on attachment in view point of the developmental perspective which began in the 1940s progressed during several decades. Many investigators focused mother-child separation in early attachment studies, and moved to the relationship with childhood psychopathology. Recently attachment theory and research are moving forward along the intergenerational transmission of attachment patterns, and adolescents and adult mental disorders in the developmental perspectives. Methods:We surveyed the research papers through Medline search, attachment-related monographs, and review or original papers published in Korean journal. Results:Developmental attachment researches have demonstrated convincingly that insecure attachment in infancy is associated with attachment disorder; several childhood psychopatholgy, such as institutional care and adoption, aggression and behavioral problems, childhood anxiety disorders and depressive disorders, gender identity disorder and feeding disorder, and child abuse and maltreatment; peer relationship and social competency, and parental behaviors. Recently the methodological advances including the Adult Attachment Interview that systematically assesses the adults' recollections of the earlier parent-child relationship they experienced could move beyond attachment researcher's initial concern with infancy to consider attachment processes throughout the life span. We could find that the quality of attachment was associated with several mental disorders in adolescents and adults significantly. Conclusion:Attachment theory would have focused on more specific parent-child relationship than general parental behavior. Recent attachment theory underscores its evolutionary origins to promote development of infant and contribute to human survival in psychobiological bases. Advances in attachment research could unite interests in evolutional biology and developmental psychology in understanding early parent-child relationship, and apply to clinical issues concerning mental health throughout the life span.

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Comparative legal review between national R&D projects and defence R&D programs - A study on improvement of royalty system for the promotion of aircraft industry - (국가연구개발사업 및 국방연구개발사업 간 비교법적 검토 - 항공기산업 진흥을 위한 기술료 제도 개선에 관한 연구 -)

  • Lee, Hae-Jun;Kim, Sun-Ihee
    • The Korean Journal of Air & Space Law and Policy
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    • v.35 no.1
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    • pp.153-180
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    • 2020
  • This study is meaningful in finding out what legal and policy issues need to be improved in order to foster the aircraft industry, which is relatively underdeveloped compared to the fact that some heavy industries, such as the automobile industry and shipbuilding industry, have achieved a high level of production and technology globally. Korea's aircraft industry has been growing at a slower pace than other industries, largely due to the country's economic growth and the lack of a market structure to properly use variables such as the level of development in related industries, aircraft technology and demand for aircraft manufacturing. While most industries are privately led by the market structure of the competition system, heavy industries such as the aircraft industry generally grow under the market structure of the incomplete competition system, because only by securing huge initial investment costs, high technology, and sufficient demand, they can maintain minimum economic feasibility. The Korean aircraft industry was focused on developing and mass-producing military aircraft focusing on military demand, but it sought to turn the tide by signing the BASA (Bileral Aviation Safety Agreement) with the U.S. A preliminary feasibility study was conducted in 2010 to develop next-generation medium-sized aircraft, but was cancelled due to differences in position with Canada's Bombardier, which is subject to the concourse, and Korea Aerospace Industries (KAI) is pushing for the production of Bombardier's Q400 license on its own. Compared to the mid-to-large sized civil aircraft that are facing difficulties in development, KAI and KARI are successfully developing technologies to unmanned aerial vehicles and civil helicopters. In addition, the unmanned aerial vehicle sector is not yet suitable for manufacturers that have an exclusive global influence, so we believe that it is necessary to pursue government-led research and development projects with a focus on the areas of commercial helicopters and unmanned aerial vehicles in order to foster the aircraft industry in the future. In addition, since military aircraft such as KT-1 and T-50 are currently being exported smoothly, and it cannot be overlooked that the biggest demand for aircraft manufacturing in the Korea is the military, it is necessary to push forward national R&D projects and defense R&D program simultaneously to enable both civilian-military development. However, there are many differences between the two projects in the way they are implemented, the department in charge and the royalty system. Through this study, we learned about the technology ownership and implementation rights of national R&D projects and defense R&D programs, as well as the royalty system. In addition, problems with the system were identified and improvement measures were derived.

The Non-Appropriation Principle and Corpus Juris Spatialis (비전유원칙과 우주법(Corpus Juris Spatialis))

  • Kim, Han-Taek
    • The Korean Journal of Air & Space Law and Policy
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    • v.35 no.1
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    • pp.181-202
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    • 2020
  • The Non-Appropriation Principle was stipulated in the OST and the MA. However the MA, creating CHM in international law for the first time, attempted to further limit the prohibitions to include ownership of resources extracted from celestial bodies, its rejection by the U.S. and most of the international spacefaring community prevented it from serving as a binding international treaty. Individuals or private enterprises intending to perform space exploitation must receive approval from the nation and may not appropriate outer space or celestial bodies. In the course of this space activity, each party will be liable. Articles 6 and 7 of the OST and the Liability Convention of 1972 deal with matters concerning those problems. The CSLCA of 2015 and Luxembourg Space Resources Law of 2017 allows States to provide commercial exploration and use of space resources to their own nationals and to companies operated by other countries within their territory. These laws do not violate Article 2 of the OST. In the case of the CSLCA of 2015, the law clearly states that it cannot claim ownership, sovereignty or jurisdiction over certain celestial bodies. Even if scholars claim that the U.S. CSLCA and Luxembourg Space Resources Law violate the non-appropriation principle of the OST, they cannot prevent these two countries from extracting the space resources on "the first come, first served" basis. The legal status of outer space including the moon and other celestial bodies is res extra commercium, like the high seas, where the fishing vessels from each country catch and sell fish without occupying the sea. Major space-faring nations must push for the adoption of an international regulatory committee which will oversee applications and issue permits based on a set of robust, modern, and forward-thinking ideals that are best equipped to govern and protect outer space as individuals, businesses, and nations compete to commercialize space through mining and the extraction of space-based resources. The new Corpus Juris Spatialis on the development of space resources, whether it is a treaty or a soft law such as recommendation and declaration, in the case of the Moon and Mars, will cover a certain amount of area to develop, and the development period by the states should be specified.

The present situation and trend of China archives science (중국(中國) 당안학(檔案學)와 현황(現況) 및 발전추세(發展趨勢))

  • Feng, Fuj-Ling
    • Journal of Korean Society of Archives and Records Management
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    • v.1 no.1
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    • pp.37-52
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    • 2001
  • 1. establishment and development of China archives science: With the centuries-old history of archives and archives management, early China archives science came into being in 1930s, and the research pushed forward by archives enterprise has made great achievements since then. 1.1 Expanding research fields: Foundation

Interactive analysis tools for the wide-angle seismic data for crustal structure study (Technical Report) (지각 구조 연구에서 광각 탄성파 자료를 위한 대화식 분석 방법들)

  • Fujie, Gou;Kasahara, Junzo;Murase, Kei;Mochizuki, Kimihiro;Kaneda, Yoshiyuki
    • Geophysics and Geophysical Exploration
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    • v.11 no.1
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    • pp.26-33
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    • 2008
  • The analysis of wide-angle seismic reflection and refraction data plays an important role in lithospheric-scale crustal structure study. However, it is extremely difficult to develop an appropriate velocity structure model directly from the observed data, and we have to improve the structure model step by step, because the crustal structure analysis is an intrinsically non-linear problem. There are several subjective processes in wide-angle crustal structure modelling, such as phase identification and trial-and-error forward modelling. Because these subjective processes in wide-angle data analysis reduce the uniqueness and credibility of the resultant models, it is important to reduce subjectivity in the analysis procedure. From this point of view, we describe two software tools, PASTEUP and MODELING, to be used for developing crustal structure models. PASTEUP is an interactive application that facilitates the plotting of record sections, analysis of wide-angle seismic data, and picking of phases. PASTEUP is equipped with various filters and analysis functions to enhance signal-to-noise ratio and to help phase identification. MODELING is an interactive application for editing velocity models, and ray-tracing. Synthetic traveltimes computed by the MODELING application can be directly compared with the observed waveforms in the PASTEUP application. This reduces subjectivity in crustal structure modelling because traveltime picking, which is one of the most subjective process in the crustal structure analysis, is not required. MODELING can convert an editable layered structure model into two-way traveltimes which can be compared with time-sections of Multi Channel Seismic (MCS) reflection data. Direct comparison between the structure model of wide-angle data with the reflection data will give the model more credibility. In addition, both PASTEUP and MODELING are efficient tools for handling a large dataset. These software tools help us develop more plausible lithospheric-scale structure models using wide-angle seismic data.

A Study on the possibility about genre extension of korean verse and modern novel in Multimedia age (다매체시대, 시조와 현대소설을 통한 장르 확장의 가능성 고찰 - 생태학적 상상력을 중심으로 -)

  • Hur, Man-Ook
    • Sijohaknonchong
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    • v.25
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    • pp.75-100
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    • 2006
  • This treatise puts with ecology that important topic is becoming in Multimedia age today. Is appearing to some meaning that symbol that. Is nature friendship and nature assimilation in korean verse and modern novel. And is the purpose to draw diachronic and synthetic thought between age and genre is forming by ecological imagination how. Our korean verse thinks of nature as residing space, and is singing life that is nature friendship and nature assimilation in relation of indivisibility sto of human and nature. And nature space of metaphor or symbol is forming by ecological imagination in the modern novel. Therefore, these two genres see that traffic is available in diachronic synthetic relation. First, must escape resolutely in ideas that literature is basing in actuality and search the literature-ecological imagination. Therefore, forward literature may have to look for the literature-ecological imagination with many interests to green literature ecology and show image that move constantly. And must approach appearing common view of nature and the literature-ecological imagination in principle of integration of expropriation and production now all round to our literary productions. Therefore, must do so that can be nature friendship and become practical education model that expropriation of ecological literary productions and production activity foster literary sensibility and imagination. Also, lively research and groping about each genre of a Korean literature are to premised in diachronic and synthetic veins I will. Method groping that adapt on New Age as defending peculiar special quality that founder is keeping korean verse with opened thinking may have to be spread more hard. Therefore, genre of novel can may ready the one clue to grope confrontation method naturally to secure new identity in new literature environment of digital age.

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