• Journal of Information Display
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• 제11권2호
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• pp.76-83
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• 2010

This paper presents the multi-user autostereoscopic 3D display system constructed and operated by the authors using the time-multiplexing approach. This prototype has three main advantages over the previous versions developed by the authors: its hardware was simplified as only one optical array is used to create viewing regions in space, a lenticular multiplexing screen is not necessary as images can be produced sequentially on a fast 120Hz LCD with full resolution, and the holographic projector was replaced with a high-frame-rate digital micromirror device (DMD) projector. The whole system in this prototype consists of four major parts: a 120Hz high-frame-rate DMD projector, a 49-element optical array, a 120Hz screen assembly, and a multi-user head tracker. The display images for the left/right eyes are produced alternatively on a 120Hz direct-view LCD and are synchronized with the output of the projector, which acts as a backlight of the LCD. The novel steering optics controlled by the multiuser head tracker system directs the projector output to regions referred to as exit pupils, which are located in the viewers’eyes. The display can be developed in the "hang-on-the-wall"form.

• 한국전기전자재료학회논문지
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• 제30권4호
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• pp.241-245
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• 2017

This paper proposes a private display that can adjust viewing angles by using an electric-field-driven (EFD) LC Lens. The EFD LC Lens design and simulation were analyzed by using the Extended Jones Matrix Method. The conventional method for attaching a private film to the display was difficult. In order to solve this problem, in this study, by using the EFD LC Lens, we devised a method that can view images more conveniently. We analyzed the luminance and illumination of the optical viewing distance by using the Extended Jones Matrix Method. We also measured the intensity of the viewing angles. The simulation attached the EFD LC Lens to the 14" Full HD RGB stripe wide panel. We calculated the relative luminance distribution and the luminance distribution on the viewing angle of the image at the optimum viewing distance of 60 cm, using the EFD LC Lens and the lenticular lens. The proposed method could be used to design private displays that can adjust the viewing angle of the EFD LC Lens.

• 천문학회지
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• 제36권3호
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• pp.213-222
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• 2003

We review recent observational results on early type galaxies obtained with high spatial resolution Chandra data. With its unprecedented high spatial resolution, Chandra reveals many intriguing features in early type galaxies which were not identified with the previous X-ray missions. In particular, various fine structures of the hot ISM in early type galaxies are detected, for example, X-ray cavities which are spatially coincident with radio jets/lobes, indicating the interaction between the hot ISM and radio jets. Also point sources (mostly LMXBs) are individually resolved down to Lx = a few x $10^{37}\;erg\;sec^{-1}$ and it is for the first time possible to unequivocally investigate their properties and the X-ray luminosity function. After correcting for incompleteness, the XLF of LMXBs is well reproduced by a single power law with a slope of -1.0 - -1.5, which is in contrast to the previous report on the existence of the XLF break at Lx, Eddington = 2 x $10^{38}\;erg\;sec^{-1}$ (i.e., Eddington luminosity of a neutron star binary). Carefully considering both detected and undetected, hidden populations of point sources we further discuss the XLF of LMXBs and the metal abundance of the hot ISM and their impact on the properties of early type galaxies.

• 천문학회지
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• 제24권2호
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• pp.151-159
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• 1991

Using the photographic imagery of the SO galaxy NGC 5102, the equivalent luminosity profile and the fractional integrated luminosity curve have been derived. Several photometric parameters of the galaxy, such as a total magnitude ($B_T$), equivalent radius ($r^*_e$), effective surface brightness (${\mu}^*_e$), and concentration indices ($C_{21}$, $C_{32}$) were derived from the luminosity profiles. According to the decomposition method from the nonlinear least squares fitting, photometric parameters of the bulge (${\mu}_e$, $r_e$) and the exponential disk (${\mu}(0)$, ${\alpha}^{-1}$), and the bulge to total luminosity ratio (B/T) were obtained. The derived central disk surface brightness (${\mu} (0)\;=\;22.06\;{\pm}\;0.18\;mag/\Box"$) and the evaluated B/T ratio (= 0.52) of the NGC 5102 are close to the mean values (${\mu} (0)\;=\;21.65\;{\pm}\;0.3\;mag/\Box"$, B/T=0.63) of the SO galaxies. Analysis showed that a lens-like hump is embedded in the equivalent luminosity profile of the NGC 5102.

• 천문학논총
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• 제30권2호
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• pp.487-488
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• 2015

In type Ia supernovae (SNe Ia) cosmology, a well-established correlation exists between the mass of host galaxies and the Hubble residual (HR) of SNe Ia. In order to investigate the origin of this correlation, we used low-resolution spectroscopic data of early-type host galaxies obtained from our YOnsei Nearby Supernovae Evolution Investigation (YONSEI) project. We measured velocity dispersions and Lick/IDS absorption line indices from these fully calibrated spectra. These indices were used to estimate the luminosity-weighted mean age, metallicity and mass of host galaxies. We found a tight correlation between host mass and population age, which is consistent with the "downsizing" trend in early-type galaxies. This suggests that the well-established correlation between HR and host mass is most likely due to the difference in population age. More observations, which are in progress, are required to understand the impact of luminosity evolution on SNe Ia cosmology.

• Journal of Microbiology and Biotechnology
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• 제24권3호
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• pp.334-336
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• 2014

A new species named Aspergillus cumulatus sp. nov. is described in Aspergillus section Aspergillus (Eurotium state). The type strain (KACC $47316^T$) of this species was isolated from rice straw used in meju fermentations in Korea, and other strains were isolated from the air in a meju fermentation room. The species is characterized by growth at a wide range of water activities and the formation of aerial hyphae on malt extract 60% sucrose agar (ME60S) that resemble a cumulus cloud. Furthermore, A. cumulatus produces yellow ascomata containing small lenticular ascospores (5.1-5.7 ${\mu}m$) with a wide furrow, low equatorial crests, and tuberculate convex surface. The species is phylogenetically distinct from the other reported Aspergillus section Aspergillus species based on multilocus sequence typing using rDNA-ITS, ${\beta}$-tubulin, calmodulin, and RNA polymerase II genes.

• 에너지공학
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• 제13권3호
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• pp.181-190
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• 2004

Computational models for analyzing the in-reactor behavior of metallic fuel pins under transient conditions in liquid-metal reactors are developed and implemented in the TRAMAC (TRAnsient thermo-Mechanical Analysis Code) for a metal fuel rod under transient operation conditions. Not only the basic models for a fuel rod performance but also some sub-models used for transient condition are installed in TRAMAC. Among the models, a fission gas release model, which takes the multi-bubble size distribution into account to characterize the lenticular bubble shape and the saturation condition on the grain boundary and the cladding deformation model have been developed based mainly on the existing models in the MAC-SIS code. Finally, cladding strains are calculated from the amount of thermal creep, irradiation creep, and irradiation swelling. The cladding strain model in TRAMAC predicts well the absolute magnitudes and gen-eral trends of their predictions compared with those of experimental data. TRAMAC results for the FH-1,2,6 pins are more conservative than experimental data and relatively reasonable than those of FPIN2 code. From the calculation results of TRAMAC, it is apparent that the code is capable of predicting fission gas release, and cladding deformation for LMR metal fuel finder transient operation conditions. The results show that in general, the predictions of TRAMAC agree well with the available irradiation data.

• Fisheries and Aquatic Sciences
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• 제21권11호
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• pp.31.1-31.7
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• 2018

Three economic marine algae that have been used as food and carrageenan sources were collected from Korea during a survey of marine algal flora. They share the generic features of Hypnea, and three major clades supported by the sectional features were confirmed in a phylogenetic tree based on rbcL sequences. The first species, which belongs to a species group corresponding to the sect. Spinuligerae, nests in the same clade with Hypnea yamadae in a genetic distance of 0%. It is morphologically characterized by an entangled base, subcompressed or subterete to terete axes, somewhat percurrent main axis, irregularly alternately branching with wide angle, and rarely hooked spinous branchlets. The second one is also referred to the sect. Spinuligerae and formed the same clade as Hypnea cenomyce. The genetic distance between both sequences was calculated as 0.0-0.1%, which is considered to be intraspecific. This species is distinct by somewhat entangled thallus at the basal part, percurrent axis, short spine-like branchlets densely covering the axis, and medullary lenticular thickenings. The third alga, which forms a species group corresponding to the sect. Pulvinatae, nests in the same clade as Hypnea nidulans (no intraspecific divergence). It shows occasionally epiphytic habitat rather than epilithic habitat of low mat-forming growth and percurrent erect main axes with dense lateral branchlets. Based on these morphological and molecular data, the three Korean species are identified as H. yamadae, H. cenomyce, and H. nidulans. This is the first record of the Hypnea species in Korea.

• Journal of information and communication convergence engineering
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• 제19권2호
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• pp.108-113
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• 2021

Multiview autostereoscopic three-dimensional (MA3D) displays have the disadvantage that the single-view resolution decreases as the number of views increases. Furthermore, the resolution of MA3D displays is relatively degraded, even though the resolution of two-dimensional displays has increased recently. Therefore, it is unattractive to consumers, and the single-view resolution enhancement of MA3D displays is required. In this study, we developed a method for supplementing the single-view resolution of MA3D displays using a plate beam splitter that can show two MA3D displays simultaneously. By applying our proposed method, the resolution of a single view can increase, and the visual obstruction by the optical plate, which is a problem for MA3D displays, can be solved. In addition, an MA3D display was optically designed and fabricated using a parallax barrier. Finally, the experimental optical results obtained using the proposed method and the only MA3D display were compared.

• ALGAE
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• 제37권1호
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• pp.15-32
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• 2022

Inspecting herbaria collections of Laurencia rigida highlighted frequent misidentifications between L. rigida and L. heteroclada f. decussata, two poorly studied taxa from Australia. Recent collections of DNA material, including from topotype material, allowed for re-examination of these two taxa using molecular techniques. Detailed morphological and molecular analyses based on two markers (rbcL and COI-5P) strongly supported these two taxa as being distinct from each other and requiring nomenclatural changes. Comprehensive morphological analyses highlighted features useful for accurate identifications. Interestingly, L. rigida was found to belong to the genus Palisada with evidence from both the morphology and molecular data. Therefore, this study proposed recognizing L. rigida as Palisada rigida comb. nov. Molecular data for L. heteroclada f. decussata on the other hand supported its separation from L. heteroclada, with too great a molecular distance to be considered a variety. Morphological characters that best separated P. rigida from L. decussata included seven characters; number of pericentral cells per vegetative axial segment, the presence of secondary pit connections, the presence of lenticular thickenings, tetrasporangia alignment, the presence of corps en cerise, holdfast morphology, and overall plant shape. Morphologically, L. heteroclada f. decussata was also separated from L. heteroclada, particularly by the following characteristics; ultimate branchlets morphologies, lower order branch lengths, primary axis and holdfast morphologies. Therefore, it was proposed that L. heteroclada f. decussata is recognized at a species level as L. decussata comb. et stat. nov.