• Proceedings of the Materials Research Society of Korea Conference
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• 2000.11a
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• pp.144-144
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• 2000

• ETRI Journal
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• v.44 no.1
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• pp.85-93
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• 2022

We propose an efficient method for synthesizing mesh-based realistic computer-generated hologram (CGH). In a previous nonanalytic mesh-based CGH synthesis, the angular spectrum of the two-dimensional (2D) plane is calculated using the fast Fourier transform (FFT) with the same size as the resolution of the final hologram. Because FFT increases the computation time as the size of the input matrix increases, the previous method has a problem: The higher the resolution of the hologram, the greater the computational load, thereby delaying synthesis time. In this study, when calculating the angular spectrum of the 2D plane in mesh-based CGH synthesis, we propose a method to calculate the angular spectrum by defining the 2D plane with an arbitrary size smaller than the resolution of the final hologram. The resolution adjustment method reduces the computation time and can be applied to occlusion culling and texturing for the realistic effect of mesh-based CGH. We describe the principle, error analysis, application of realistic effect, and experimental results of the proposed method.

• Macromolecular Research
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• v.16 no.8
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• pp.686-694
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• 2008

We studied the molecular shapes and structural characteristics of a 33-armed, star polystyrene (PS-33A) and two $3^{rd}$-generation, dendrimer-like, star-branched poly(methyl methacrylate)s with different architectures (pMMA-G3a and PMMA-3Gb) and 32 end-branches under good solvent and theta ($\Theta$) solvent conditions by using synchrotron small angle X-ray scattering (SAXS). The SAXS analyses were used to determine the structural details of the star PS and dendrimer-like, star-branched PMMA polymers. PS-33A had a fuzzy-spherical shape, whereas PMMA-G3a and PMMA-G3b had fuzzy-ellipsoidal shapes of similar size, despite their different chemical architectures. The star PS polymer's arms were more extended than those of linear polystyrene. Furthermore, the branches of the dendrimer-like, star-branched polymers were more extended than those of the star PS polymer, despite having almost the same number of branches as PS-33A. The differences between the internal chain structures of these materials was attributed to their different chemical architectures.

• ETRI Journal
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• v.31 no.4
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• pp.457-459
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• 2009

The optimum maximum voiced frequency (MVF) estimation-based two-band excitation for hidden Markov model-based speech synthesis is presented. An analysis-by-synthesis scheme is adopted for the MVF estimation which leads to the minimum spectral distortion of synthesized speech. Experimental results show that the proposed method significantly improves synthetic speech quality.

• Toxicological Research
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• v.15 no.1
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• pp.35-38
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• 1999

RNA synthesis rate was measured at different time points after UV irradiation in various xeroderma pigmentosum (XP) cells including complementation groups F and G. The RNA synthesis was assayed by measuring 3H-uridine incorporation. In normal cells, recovery of RNA synthesis was initiated at about 6 hr ager UV irradiation and reached to the same level as in unirradiated cells at 24hr after UV irradiation. By contrast, no such recovery was observed in group F,G XP cells.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.95-95
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• 2018

In this study, we investigated the effect of branch extracts from Vaccinium oldhamii (VOB) on melanin synthesis in B16F10 cells. VOB promoted melanin production in absence or presence of ${\alpha}$-melanocyte-stimulating hormone (${\alpha}-MSH$) in B16F10 cells. However, VOB did not affect the expression of tyrosinase and TRP-1 associated with melanin synthesis at the mRNA and protein level in B16F10. But, VOB decreased TRP-2 protein level and induced tyrosinase activation in B16F10 cells. Inhibition of tyrosinase activity and tyrosinase knockdown attenuated VOB-mediated melanin synthesis. In conclusion, it is thought that VOB may stimulate melanin synthesis through activating tyrosinase activity.

• Journal of Korean Society on Water Environment
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• v.20 no.6
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• pp.692-697
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• 2004

Biological phosphorus removal is characterized by complex interactions between different intracellular components of energy as PHA. Therefore, fundamental understanding of the behavior of the intracellular components and their influence on the removal of phosphorus is essential before control strategies to stabilize the proper process. The purpose of this study is to investigate relationship between release of phosphorus and synthesis of intracellular storage polymer. Mass of stored intracellular storage polymer was 21.2 mg PHA/L, 28.8 mg PHA/g MLSS. And phosphorus release/intracellular storage polymer synthesis rate was 1.8545 mg stored polymer/mg Phosphate. In the aerobic phase, mass of PAOs synthesis is 49.37 mg PAOs/L. And PAOs fraction was 6.7-6.9%. Thus intracellular storage polymer synthesis by PAOs is calculated as 493mg PHA/g PAOs.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.301-301
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• 2006

The physical properties of well-defined star-shape polystyrenes with high number of arms (6 to 57 arms) in good and theta solvents were studied using synchrotron X-ray scattering. The scattering profiles for multi-armed polystyrenes shown the molecular shape is changed according to increasing of number of arm. From various parameters which were obtained from scattering profiles, the molecular shape was determined more detail. As results, the molecular shape was changed from a fuzzy-ellipsoid for 6-armed PS to a fuzzy-sphere sphere for 57-armed PS according to increasing of number of arm.

• Clean Technology
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• v.22 no.3
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• pp.196-202
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• 2016

In this study, ceria- based catalysts were prepared for dimethyl carbonate (DMC) synthesis and reaction conditions were evaluated for finding the optimal reaction route. In order to find optimal catalysts for DMC synthesis, calcination temperature and Cu(II) impregnation amount were evaluated. The oxidative carbonylation using methanol, carbon monoxide and oxygen and the direct synthesis using methanol and carbon dioxide were introduced for producing DMC. Following the law of Le Chatelier, the dehydration reaction was applied for enhancing the reactivity (methanol conversion) as removing water during the reaction. 2-cyanopyridine, as a chemical dehydration agent, was used. In the case of the oxidative carbonylation, methanol conversion rate increased from 15.1% to 38.7% and the DMC selectivity increased from 0% to 98.8%. In the case of the direct synthesis, methanol conversion rate increased from 1.0% to 77.8% and the DMC selectivity increased from 41.2% to 100.0%.

• Animal cells and systems
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• v.7 no.3
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• pp.227-235
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• 2003

Bisphenol A (BPA), nonylphenol (NP), and 4-tert-octylphenol (OP) are known endocrine disrupting chemicals (EDCs) with estrogenic activity in fish. This study compared the effects of BPA, NP and OP on in vitro vitellogenin (VTG) synthesis in primary cultures of hepatocytes of the Chinese minnow Phoxinus oxycephalus. The VTG secreted into the culture medium was measured using enzyme-linked immunosorbent assay (ELISA), which we developed in this study using an antibody prepared from homogenates of Chinese minnow egg. VTG synthesis was induced by estradiol-17$\beta$ ($E_2$) and phenols (BPA, NP and OP) treatment. $E_2$ at concentrations of 10$^{-6}$ M or higher increased VTG levels significantly (P < 0.05). Exposure to 10^5\;M\;BPA\;or\;10^-4$M NP and OPinduced in vitro VTG synthesis (P < 0.01). However, $10^-3$ M BPA, NP or OP did not induce VTG synthesis. These results suggest that SPA has the highest estrogenic potential in Chinese minnow hepatocytes. Tamoxifen, an anti-estrogen, drastically blocked the production of VTG by phenols (BPA, NP and OP) suggesting that phenols (BPA, NP and OP) may act via binding to estrogen receptor (ER) in Chinese minnow hepatocytes.