• 제목/요약/키워드: LED Direct

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Study of the Effect of the Transmittance of a Diffuser Plate on the Optical Characteristics of High-power Quantum-dot Illumination (확산판의 투과율이 고출력 양자점 조명의 광특성에 미치는 영향에 대한 연구)

  • Kim, Hye-Rin;You, Dong Geun;You, Jae Hwan;Jang, Jun Won;Choi, Moo Kyu;Hong, Seung Chan;Ko, Jae-Hyeon;Joe, Sung-Yoon;Kim, Yongduk;Park, Taehee;Ko, Young Wook
    • Korean Journal of Optics and Photonics
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    • 제32권5호
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    • pp.220-229
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    • 2021
  • The optical characteristics of high-power direct-lit white light-emitting diode (LED) lighting were investigated, where a quantum dot (QD) film was adopted to enhance the color-rendering index (CRI). The transmittance of the diffuser plate and the concentration of the QD film were varied in this study. The color coordinates and the correlated color temperature (CCT) did not show any appreciable change, while the CRI values increased slightly as the transmittance of the diffuser plate decreased. The investigated optical properties were nearly independent of the viewing angle, and the luminance distribution was close to Lambertian. The CCT decreased from approximately 6000 K to approximately 4000 K as the concentration of the QD film increased from 0 to 7.5 wt%, which was due to the enhanced red component in the emission spectrum. The CRI increased to approximately 95 for some optical configurations of the lighting. These results demonstrate that glare-free, color-changeable, high-rendering LED lighting can be realized by using a combination of a diffuser plate of appropriate transmittance and a red QD film.

An Integrated Approach in the Pest Management in Sericulture

  • Singh, R.N.;Saratchandra, Beera
    • International Journal of Industrial Entomology and Biomaterials
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    • 제5권2호
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    • pp.141-151
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    • 2002
  • The success of sericulture industry in India is mainly attributed to the well-planned annual sericultural activity and the systematic implementation of pest preventive and control measures. The insect spectrum of silkworm and its food plants is complex and plays a major role in limiting the production of silk. Insects cause extensive damage to plant whereas predators and parasites either kill the silkworm larvae or force them to spin flimsy cocoons. Unilateral control measure against this pest is mainly based on the use of synthetic organic insecticides. Though these approaches initially paid rich dividends, the undesirable consequences soon surfaced. Insecticide induced resurgence of gall midges, leafhopper, leaf roller, secondary pest out breaks and development of pest biotypes has led to realization of Integrated Pest Management in sericulture. Various components of IPM, viz. Host plant resistance, cultural practices, biological control, chemical control and integrating them at various technological levels have been studied. Sources of host plant resistance have been identified for some of the major insect pests. High yielding mulberry variety has been propagated and their resistances towards major pests have been recorded. Cultural practices like pruning, pollarding, judicious use of nitrogen, optimum spacing and weed management have preyed to be the powerful tools in containing pests. Natural control over the pest population build- up exerted by the wide range of parasitoids, predators and pathogens has been well documented with identification of natural enemies and studies on their potential. Augmentation, through inoculation or inundative releases of parasitic arthropods, is the most direct way of increasing the numbers of these beneficials in sericulture.

The Effect of Pretreatment of Raw Powders on the Photoluminescence of Ca-α-SiAlON:Eu2+ Phosphor

  • Park, Young-Jo;Kim, Jin-Myung;Lee, Jae-Wook
    • Journal of the Korean Ceramic Society
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    • 제51권5호
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    • pp.413-417
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    • 2014
  • The effect of calcination treatment of raw powders prior to high temperature synthesis of Ca-${\alpha}$-SiAlON:$Eu^{2+}$ phosphor was investigated. Based on data acquired from thermogravimetric analysis, calcination temperatures were set at 600, 750, and $900^{\circ}C$. Compared to the photoluminescence (PL) intensity of direct synthesis without calcination, a similar intensity was found for the $600^{\circ}C$ treatment, a 19% increased PL intensity was found for the $750^{\circ}C$ treatment, and a 23% decreased PL intensity was found for the $900^{\circ}C$ treatment. Observation of the particle morphology of the synthesized phosphors revealed that the material transport promoted through the agglomerates formed by the $750^{\circ}C$ treatment led to enhanced PL intensity. On the other hand, the oxidation of the starting AlN particles during the $900^{\circ}C$ treatment resulted in decreased photoluminescence.

The Relationship between the Career Preparation Behavior, Parental Social Support, Career Decision Making Self-Efficacy, and the Career Maturity of the Pre-Service Elementary School Teachers (교육대학생의 진로준비행동과 부모의 사회적 지지, 진로결정자기효능감 및 진로성숙의 관계)

  • Keum, Jiheon
    • Journal of the Korean Home Economics Association
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    • 제50권7호
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    • pp.59-66
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    • 2012
  • The purpose of this study was to identify a causal relationship in the career preparation behavior, parental social support, career decision making self-efficacy and the career maturity of the pre-service elementary school teachers. A total of 374 questionnaires were used for data analysis, excluding the 23 copies deemed insincere in response. To ensure the reliability and validity of the questions, technical statistics of the frequency, ratio, average, standard deviation, skewness, and kurtosis via PASW 18.0, item-total correlation, the totality, and the reliability analysis. The structural analysis via AMOS 7.0 in the bootstrapping method was undertaken to perform the path analysis among the variables and to assess the suitability of the model. The findings of the study led to the following conclusions: First, the causal model for the career preparation behavior, parental social support, career decision making self-efficacy, and the career maturity of the pre-service elementary school teachers is suitable to empirical analysis on research variables. Second, the career decision making self-efficacy of pre-service elementary teachers has direct effect on career preparation behavior positively. Third, parental social support of the pre-service elementary teachers has indirect effects on the career preparation behavior positively.

A study on the manufacture of dissimilar metal jewelry using 3D printer (3D printer를 이용한 이종금속 주얼리 제작에 관한 연구)

  • Lee, Jung-Soo;Cha, Kyung-Chul
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • 제26권1호
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    • pp.19-22
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    • 2016
  • In the late 1990's implementation of CAD/CAM systems in 3D printer has been led to many changes in the jewelry industry. Low cost 3D printer has been started advertising in the jewelry in 2009 after expiration of key patents of FDM scheme. Mass jewelry production process will vary in appliance with direct production process of 3D printer production line. The studies presented in this variation is the jewelry manufacturing process using a 3D Printer and the different metals with different colors were also produced for bonding the prototype jewelry. Increasing the possibilities of 3D printer through them, presents a variety of jewelry mass production methods.

The Influences of Covert Narcissism on Displaced Aggression in Late Childhood: The Mediating Effects of Internalized Shame and Rejection Sensitivity (학령후기 아동의 내현적 자기애가 전위 공격성에 미치는 영향: 내면화된 수치심과 거부민감성의 매개효과)

  • Lim, Hye Eun;Han, Sae-Young
    • Korean Journal of Child Studies
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    • 제37권4호
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    • pp.129-143
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    • 2016
  • Objective: This study aimed to examine the mediating effects of internalized shame and rejection sensitivity in the relationship between covert narcissism and displaced aggression in late childhood. Methods: The participants included 1,060 children (grades 5 and 6; 547 boys and 513 girls) from four elementary schools located in Seoul, Gyeonggi-do, and Chungcheong-do. Results: The primary results of this study were as follows. First, child covert narcissism had a direct effect on displaced aggression; children who perceived higher levels of covert narcissism exhibited more displaced aggression. Second, child covert narcissism had an indirect effect on their displaced aggression through internalized shame and rejection sensitivity. Children who perceived higher levels of covert narcissism reported more internalized shame and rejection sensitivity, which led to more displaced aggression. Conclusion: The findings of this research indicate that individual and interpersonal psychological factors need to be considered to explain displaced child aggression. Further, it is important that we help children to gain positive relationships with family and peers. It will help them break away their negative self or others representation, especially their internalized shame and rejection sensitivity.

Effects of Physico-chemical Factors of Sol on the Degree of Preferred Orientation in $Pb(Mg, Zn)_{1/3}Nb_{2/3}O_3$ Thin Films (Sol의 물리화학적 변수들이 $Pb(Mg, Zn)_{1/3}Nb_{2/3}O_3$ 박막의 우선 배향성에 미치는 효과)

  • 조문규;장현명;김광수
    • Journal of the Korean Ceramic Society
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    • 제32권3호
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    • pp.305-312
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    • 1995
  • Thin films of Pb(Mg, Zn)1/3Nb2/3O3 were fabricated by spin coating the Pb-Mg-Zn-Nb-O complex alkoxide sols on(111) Pt-coated MgO (100) planes. It was observed that the content of H2O and the rheological characteristics of sol greatly influenced the orientation of perovskite grains after thin-film formation. A strong preferential orientation of (100)-type planes of the perovskite grains was obtained for the sol aged for 15 days with the molar ratio of H2O to total metal alkoxides=2. As small angle X-ray scattering experiment in the Porod region was performed to correlate the observed preferential orientation with the network structure of precursors at various stage of aging. It was shown that the degree of branching of the Pb-Mg-Zn-Nb-O precursor chain had a direct effect on the preferred oreintation, and weakly branched precursor systems led to highly oriented grains after thin-film formation.

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Analysis of Social Network Change Characteristics of Participants in Urban Regeneration Project Using NetMiner : Focused on the Urban Regeneration Leading Area in Suncheon-City (NetMiner를 활용한 도시재생사업 참여주체의 시기별 소셜 네트워크 변화 특성 분석 : 순천시 원도심 도시재생선도지역을 중심으로)

  • Gim, Eojin;Koo, Jahoon
    • Journal of Information Technology Services
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    • 제19권1호
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    • pp.1-16
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    • 2020
  • Suncheon City Regeneration Project is known as the concept of cultural residents. Through the previous projects, the residents' capabilities have been improved, and the projects have been carried out according to their strategies. For this reason, participants in urban regeneration projects are important. The purpose of this study is to actually identify the 'rescue center' and 'direct relationship' with the analysis utilizing the characteristics of social networks NetMiner solution of the participants, who led the project, Suncheon. Surveys and interviews were conducted for participants, and the characteristics of social networks were analyzed in time series to quantify and visualize the results. As a result of the analysis, social networks were changed among the participants before and after the urban regeneration project. Initially, loose networks were denser over time, and initially networks formed only around participants were expanded over time. Network analysis has revealed that the system is strengthening with urban regeneration projects in the form of public and public-private cooperation. This highlights the need for a city-centered urban regeneration strategy centered on people and shows that a dense network of participants can be a success factor.

THE ADVANTAGE OF ON ORBIT NON-UNIFORMITY CORRECTION FOR MULTI SPECTRAL CAMERA (MSC)

  • Chang Young-Jun;Kong Jong-Pil;Huh Haeng-Pal;Kim Young-Sun;Park Jong-Euk
    • Proceedings of the KSRS Conference
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    • 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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    • pp.586-588
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    • 2005
  • The MSC (Multi Spectral Camera) system is a remote sensing payload to obtain high resolution ground image. This system uses lossy image compression method for &Direct mission& that transmit whole image during one contact. But some image degradation occurred especially at high compression ratio. To reduce this degradation, the MSC uses NUC (Non-uniformity Correction) Unit. This unit correct CCD (Charge Coupled Device)'s high-frequency non-uniformity. So high frequency contents of image can be minimized and whole system SNR can be maximized. But NUC has some disadvantage either. It decreases entire system reliability by adding one electronic system. Adding NUC also led to difficulty of electronic design, assembly and testability. In this paper, the comparison is performed between on-orbit non-uniform correction and on ground correction. by evaluating NUC advantage for the point of view of image quality. Using real MSC parameter and proper model, considerable reference point for the system design came to possible.

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Resveratrol Inhibits Nitric Oxide-Induced Apoptosis via the NF-Kappa B Pathway in Rabbit Articular Chondrocytes

  • Eo, Seong-Hui;Cho, Hongsik;Kim, Song-Ja
    • Biomolecules & Therapeutics
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    • 제21권5호
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    • pp.364-370
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    • 2013
  • Resveratrol (trans-3,4'-trihydroxystillbene), a naturally occurring polyphenolic antioxidant found in grapes and red wine, elicits diverse biochemical responses and demonstrates anti-aging, anti-inflammatory, and anti-proliferative effects in several cell types. Previously, resveratrol was shown to regulate differentiation and inflammation in rabbit articular chondrocytes, while the direct production of nitric oxide (NO) in these cells by treatment with the NO donor sodium nitroprusside (SNP) led to apoptosis. In this study, the effect of resveratrol on NO-induced apoptosis in rabbit articular chondrocytes was investigated. Resveratrol dramatically reduced NO-induced apoptosis in chondrocytes, as determined by phase-contrast microscopy, the MTT assay, FACS analysis, and DAPI staining. Treatment with resveratrol inhibited the SNP-induced expression of p53 and p21 and reduced the expression of procaspase-3 in chondrocytes, as detected by western blot analysis. SNP-induced degradation of I-kappa B alpha ($I{\kappa}B-{\alpha}$) was rescued by resveratrol treatment, and the SN50 peptide-mediated inhibition of NF-kappa B (NF-${\kappa}B$) activity potently blocked SNP-induced caspase-3 activation and apoptosis. Our results suggest that resveratrol inhibits NO-induced apoptosis through the NF-${\kappa}B$ pathway in articular chondrocytes.