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        검색결과 616

        2.
        2025.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적 : 본 연구는 근시에서 굴스트란드 모형안에 편심 렌즈를 적용했을 때의 광학적 효과를 분석하고자 하였다. 방법 : 굴스트란드 모형안은 3D 시뮬레이션 프로그램을 사용하여 정밀하게 설계하였으며, 근축 근사 없이 정확 한 분석을 제공하는 광선 추적 기술을 적용하여 편심 렌즈로 인한 초점거리와 굴절력의 변화를 정밀하게 조사하 였다. 결과 : 렌즈 중심축의 편심이 초점거리, 굴절력, 광 경로 차이에 미치는 영향을 다양한 편심 조건에서 분석하였 으며, 특히 중심축으로부터 일정 높이에서 평행광선이 입사하는 경우를 집중적으로 조사하였다. 광선의 입사 높이 가 극도로 커짐에 따라 편심의 효과는 감소하고, 출사 광선의 초점은 서로 가까운 지점으로 위치하는 것이 확인되 었다. 렌즈와 눈의 굴절력과 편심에 따른 프리즘 굴절력 효과를 포함하는 전체 굴절력은 광선의 입사 높이가 감소 함에 따라 크게 변화하는 것으로 나타났다. 결론 : 본 연구 결과는 사시 및 사위와 같은 시각적 이상을 교정하기 위해서, 의도적으로 편심된 렌즈를 설계하 고 처방하는 데 유용한 정보를 제공할 수 있을 것으로 기대된다. 또한, 편심 렌즈 설계 시 발생할 수 있는 비선형적 광학 효과를 최소화하여 사용자에게 최적의 시각적 성능 제공을 보장할 수 있을 것으로 기대된다.
        4,300원
        3.
        2024.12 구독 인증기관 무료, 개인회원 유료
        This study explores the innovative utilization of a biomimetic electric ray friction nanogenerator (ER-TENG) in combination with electrolysis technology for the remediation of maritime effluent. The ER-TENG is ingeniously crafted with a flexible, planar structure, enabling seamless adaptation to various curved and irregular substrates such as rocks, corals, and shipwrecks on the ocean floor, obviating the necessity for specialized mounting or securing devices. Simulation results regarding the potential distribution between the copper electrode and the PDMS film under different inter-electrode distances indicate that an increase in separation distance is correlated with an enhanced potential difference on the material's surface, exhibiting a linear upward trend, with the maximum potential difference reaching 120 V. When TiO2 nanoparticles are incorporated at a doping mass fraction of 4.65 wt%, the friction nanogenerator attains its peak electrical performance, boasting a peak opencircuit voltage of 123.25 V and a maximum short-circuit current of 13.52 μA, representing increases of 2.73-fold and 2.56-fold in open-circuit voltage and short-circuit current, respectively. At operational frequencies of 1.2 Hz and 1.0 Hz, the initial stage of sterilization rate enhancement proceeds at a moderate pace. However, after 60 minutes of electrolysis, sterilization rates reach 88.12% and 46.36%, respectively. The electrical energy harvested by the ER-TENG facilitates the generation of potent oxidizing chlorine through electrolysis, which effectively eliminates harmful aquatic organisms and pathogens present in ship ballast water.
        4,000원
        4.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 춘천 문화도시 사업의 '도시가 살롱'을 올덴버그(Ray Oldenburg)의 '제3의 공간' 이론을 중심으로 분석하여, 공간의 특성과 효과를 고찰하였다. 연구방법으로는 질적 내용분석을 채택하여 문헌조사 를 중심으로 정책문서, 운영자료, 성과보고서 등을 수집하였다. 분석 결 과, ‘접근성’ 측면에서, '도시가 살롱'은 카페, 책방, 식당 등 시민들의 일 상공간을 문화공간으로 전환함으로써 접근성을 확보하여 생활권 내 문화 접근성을 향상시켰다. 둘째, ‘편의성’ 측면에서, 복합공간 구성과 통합 플 랫폼 운영을 통해 이용자 중심의 서비스를 실현했으며, 멤버십 시스템과 월 60여 개의 다양한 프로그램을 제공하여 이용 편의성을 높였다. 셋째, ‘평등성’ 측면에서 세대 통합형 프로그램, 수평적 공간구조, 'ON-다' 프 로그램 등을 통해 읍면 지역의 문화 격차 해소에 기여했다. 넷째, ‘상호 작용성’ 측면에서 시민기획자 중심의 운영으로 이웃 간 관계망을 강화했 고, '동네지식인' 프로그램을 통해 시민들의 자발적 참여와 교류를 촉진 했다. 다섯째, ‘유희성’ 측면에서, '딴짓' 키워드를 활용한 창의적 접근으 로 유희성을 구현했으며, 여섯째, ‘다양성’ 측면에서, 8개 거점 공간의 차별화된 운영과 지역특화 프로그램으로 문화적 다양성을 확보했다. 그 러나 읍면 지역의 접근성 강화, 장애인과 노약자를 위한 편의시설 확충, 문화적 소수자들의 참여 확대, 지속가능한 커뮤니티 형성, 디지털 전환 대응 그리고 민간의 주도적 운영이라는 과제가 도출되었다.
        8,400원
        5.
        2024.11 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        본 연구의 목적은 재즈 역사에서 인정받고 있는 베이스 연주자 레이 브라운의 즉흥연주 중 투필 베이스 라인을 분석하여 그 특징을 알아보고 이를 통해 , 현대 재즈 연주자들에게 그의 특징인 투 필 베이스 라인을 적용 및 재현하여 재즈의 새로운 시각을 제공하는 데에 있다. 이를 위해 연구방 법으로 재즈 음악에서 가장 기본적인 트리오 구성(피아노, 베이스, 드럼)에서 베이스의 워킹 베이 스 라인 중 레이 브라운의 연주곡 6곡을 선정하여 투 필 베이스 라인의 리듬과 하모니를 심층 분석 하였고 그 결과를 다른 3곡에 적용시켜 레이 브라운 스타일의 예제를 만들었다. 본 연구에서 레이 브라운의 선율적 특징과 화성적 특징, 그리고 리듬적 특징, 테크닉적인 특징을 분석하고 적용하였 고, 선율적 특징은 콜 앤 리스폰스 주법을 사용하였고, 화성적 특징은 가이드 톤 라인을 사용하여 도미넌트 모션을 4번째 박자에 사용하였다. 리듬적 특징으로는 투 필 베이스 라인에서 2분음표로 만 연주하는 것이 아니라 2, 4마디에서는 포비트 워킹 베이스 라인을 연주하여 리듬에 안정감을 더한다는 결과를 도출해 내었다. 이러한 레이 브라운의 고찰이 객관적인 자료로 남아 투 필 베이 스 라인에 대한 기준을 제시해 다른 재즈 베이스 연주자들에게 도움이 됐으면 하고, 솔로 라인이 나 포 비트 워킹 베이스 라인, 솔리스트로서의 발전에 도움이 될 수 있기를 기대하는 바이다.
        6,700원
        8.
        2024.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this study, we conduct a multi-frequency analysis of the gamma-ray bright blazar 1308+326 from February 2013 to March 2020, using the Korean VLBI Network at 22 and 43 GHz and gamma-ray data from the Fermi Large Area Telescope (LAT). Our findings reveal spectral variations around the 2014 gamma-ray flare, aligning with the shock-in-jet model. A strong correlation is observed between gamma-ray and 43 GHz emissions, with a 27-day lag in the VLBI core light curve, indicating a 50-day delay from the beginning of a specific radio flare to the gamma-ray peak. This radio flare correlates with a new jet component, suggesting the 2014 gamma-ray flare resulted from its interaction with a stationary component. Our analysis indicates the 2014 gamma-ray flare originated 40–63 parsecs from the central engine, with seed photons for the gamma-ray emission unlikely from the broad-line region.
        4,900원
        9.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we examined the effects of gamma irradiation dosage on the mycelial growth of Auricularia auriculajudae and performed analyses of fruiting body yield, growth characteristics, taste, fragrance, and mineral composition. Assessments of mycelial growth in response to gamma irradiation at different intensities revealed an enhancement in the growth of fungi exposed to irradiation at 200 Gy. Fruiting body yield was also highest at 200 Gy, followed by 800 Gy and the control group. On the basis of these observations, we subsequently applied gamma ray doses of 200 and 800 Gy to examine the effects of irradiation on fungal quality characteristics. In terms of the taste of fruiting bodies, we detected no significant differences among the control, 200 Gy, and 800 Gy groups. Contrastingly, with respect to fragrance, we found that fungi treated with 200 Gy were characterized by a pattern that differed from those of the control and other treatment groups. Furthermore, whereas we detected no significant difference among treatments with respect total dietary fiber content, calcium content was found to be higher in the treatment groups compared with the control group, with the highest content being measured in fungi exposed to 800 Gy irradiation. Copper content was confirmed to be higher in the control group, whereas there were no significant differences between the fungi irradiated with 200 and 800 Gy. Contrastingly, the highest levels of zinc were detected in response to 200 Gy irradiation, followed by 800 Gy. Collectively, our findings thus indicate that gamma irradiation can contribute to promoting increases in the fruiting body yield and mineral contents of mushrooms.
        4,000원
        11.
        2023.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We present the analysis results of the simultaneous multifrequency observations of the blazar 4C +28.07. The observations were conducted by the Interferometric Monitoring of Gamma-ray Bright Active Galactic Nuclei (iMOGABA) program, which is a key science program of the Korean Very Long Baseline Interferometry (VLBI) Network (KVN). Observations of the iMOGABA program for 4C +28.07 were conducted from 16 January 2013 (MJD 56308) to 13 March 2020 (MJD 58921). We also used γ-ray data from the Fermi Large Array Telescope (Fermi-LAT) Light Curve Repository, covering the energy range from 100 MeV to 100 GeV. We divided the iMOGABA data and the Fermi-LAT data into five periods from 0 to 4, according to the prosody of the 22 GHz data and the presence or absence of the data. In order to investigate the characteristics of each period, the light curves were plotted and compared. However, a peak that formed a hill was observed earlier than the period of a strong γ-ray flare at 43–86 GHz in period 3 (MJD 57400–58100). Therefore, we assumed that the minimum total CLEANed flux density for each frequency was quiescent flux (Sq) in which the core of 4C +28.07 emitted the minimum, with the variable flux (Svar) obtained by subtracting Sq from the values of the total CLEANed flux density. We then compared the variability of the spectral indices (α) between adjacent frequencies through a spectral analysis. Most notably, α22–43 showed optically thick spectra in the absence of a strong γ-ray flare, and when the flare appeared, α22–43 became optically thinner. In order to find out the characteristics of the magnetic field in the variable region, the magnetic field strength in the synchrotron self-absorption (BSSA) and the equipartition magnetic field strength (Beq) were obtained. We found that BSSA is largely consistent with Beq within the uncertainty, implying that the SSA region in the source is not significantly deviated from the equipartition condition in the γ-ray quiescent periods.
        5,800원
        13.
        2023.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The most comprehensive and particularly reliable method for non-destructively measuring the residual stress of the surface layer of metals is the sin method. When X-rays were used the relationship of sin measured on the surface layer of the processing metal did not show linearity when the sin method was used. In this case, since the effective penetration depth changes according to the changing direction of the incident X-ray,  becomes a sin function. Since  cannot be used as a constant, the relationship in sin cannot be linear. Therefore, in this paper, the orthogonal function method according to Warren’s diffraction theory and the basic profile of normal distribution were synthesized, and the X-ray diffraction profile was calculated and reviewed when there was a linear strain (stress) gradient on the surface. When there is a strain gradient, the X-ray diffraction profile becomes asymmetric, and as a result, the peak position, the position of half-maximum, and the centroid position show different values. The difference between the peak position and the centroid position appeared more clearly as the strain (stress) gradient became larger, and the basic profile width was smaller. The weighted average strain enables stress analysis when there is a strain (stress) gradient, based on the strain value corresponding to the centroid position of the diffracted X-rays. At the 1/5 max height of X-ray diffraction, the position where the diffracted X-ray is divided into two by drawing a straight line parallel to the background, corresponds approximately to the centroid position.
        4,000원
        14.
        2023.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        A Forbush decrease (FD) is a depression of cosmic ray (CR) intensity observed by ground-based neutron monitors (NMs). The CR intensity is thought to be modulated by the heliospheric magnetic structures including the interplanetary coronal mass ejection (ICME) surrounding the Earth. The different magnitude of the decreasing in intensity at each NM was explained only by the geomagnetic cutoff rigidity of the NM station. However, sometimes NMs of almost the same cutoff rigidity in northern and southern hemispheres observe the asymmetric intensity depression magnitudes of FD events. Thus, in this study we intend to see the effects on CR intensity modulation of FD event recorded at different NMs due to different ICME propagation directions as an additional parameter in the model explaining the CR modulation. Fortunately, since 2006 the coronagraphs of twin spacecraft of the STEREO mission allow us to infer the propagation direction of ICME associated with the FD event in 3-dimension with respect to the Earth. We suggest the hypothesis that the asymmetric CR modulations of FD events are determined by the propagation directions of the associated ICMEs.
        4,000원
        19.
        2022.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Using I-band images of 35 nearby (z < 0.1) type 1 active galactic nuclei (AGNs) obtained with Hubble Space Telescope, selected from the 70-month Swift-BAT X-ray source catalog, we investigate the photometric properties of the host galaxies. With a careful treatment of the point-spread function (PSF) model and imaging decomposition, we robustly measure the I-band brightness and the effective radius of bulges in our sample. Along with black hole (BH) mass estimates from single-epoch spectroscopic data, we present the relation between BH mass and I-band bulge luminosity (MBH–MI,bul relation) of our sample AGNs. We find that our sample lies offset from the MBH–MI,bul relation of inactive galaxies by 0.4 dex, i.e., at a given bulge luminosity, the BH mass of our sample is systematically smaller than that of inactive galaxies. We also demonstrate that the zero point offset in the MBH–MI,bul relation with respect to inactive galaxies is correlated with the Eddington ratio. Based on the Kormendy relation, we find that the mean surface brightness of ellipticals and classical bulges in our sample is comparable to that of normal galaxies, revealing that bulge brightness is not enhanced in our sample. As a result, we conclude that the deviation in the MBH–MI,bul relation from inactive galaxies is possibly because the scaling factor in the virial BH mass estimator depends on the Eddington ratio.
        5,700원
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