• Title/Summary/Keyword: Photo-physical

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Comparative Study of Physical Properties of Functional Ophthalmic Hydrogel Lens Using Photo and Thermal Polymerization

  • Kim, Duck-Hyun;Seok, Jae-Wuk;Sung, A-Young
    • Journal of Integrative Natural Science
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    • v.10 no.3
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    • pp.148-153
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    • 2017
  • In this study, HEMA, MMA, AA, and EGDMA were used as basic combinations for manufacturing hydrophilic lenses for ophthalmic applications. In addition, AIBN (thermal polymerization initiator), 2H2M (photo polymerization initiator), and 3-hydroxypyridine (additive) were used to manufacture hydrophilic ophthalmic lenses through thermal polymerization and photo polymerization before their physical properties were measured. The results showed that when ophthalmic lenses were prepared via thermal polymerization and photo polymerization using 3-hydroxypyridine as an additive, their optical and physical properties and surface structures were different in each case, but they all satisfied the physical properties required for ophthalmic lenses.

Photo-sensing Characteristics of VO2 Nanowires

  • Sohn, Ahrum;Kim, Eunah;Kim, Haeri;Kim, Dong-Wook
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.197.1-197.1
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    • 2014
  • VO2 has intensively investigated for several decades due to its interesting physical properties, including metal-insulator transition (MIT), thermochromic and thermoelectric properties, near the room temperature. And also gas and photo sensing properties of VO2 nanowires have attracted increasing research interest due to the high sensitivity and multi-sensing capability. We studied the light-induced resistance change of VO2 nanowires. In particular, we have investigated plasmonic enhancement of the photo-sensing properties of the VO2 nanowires. To select proper wavelength, we performed finite-difference time-domain simulations of electric field distribution in the VO2 nanowires attached with Ag nanoparticles. Localized surface plasmon resonance (LSPR) is expected at wavelength of 560 nm. The photo-sensitivity was carefully examined as a function of the sample temperature. In the presentation, we will discuss physical origins of the photo-induced resistance change in VO2.

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What You Hear is What You See\ulcorner

  • Moon, Seung-Jae
    • The Journal of the Acoustical Society of Korea
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    • v.21 no.1E
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    • pp.31-41
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    • 2002
  • This study aims at investigating the relationship between voice and the image information carried within the voice. Whenever we hear somebody talking, we form a mental image of the speaker. Is it accurate? Is there a relationship between the voice and the image triggered by the voice? To answer these questions, speech samples form 8 males and 8 females were recorded. Two photos were taken for each speaker: the whole body photo (W) with physical characteristics present, and the face close-ups (F) without much physical details revealed. 361 subjects were asked to match the voices with the corresponding photos. The results showed that 5 males and 5 f3males (with W) and 2 males and 4 females (with F) were correctly identified. More interestingly, however, even in the mismatches, there was a strong tendency for participants to agree on which voice should correspond to which photo. The participants also agreed much more readily on their favorite voice than on their favorite photo. It seems voice does carry certain information about the physical characteristics of the speaker in a consistent manner. These findings have some bearings on understanding the mechanism of speech production and perception as well as on improving speech technology.

A Research about Digital Texture for Photo Realistic Computer Graphic (Photo Realistic Computer Graphic 제작에 따른 Digital Texture 구현)

  • Eum, Young-Sik;Kim, Ji-Hong;Kim, Cheeyong
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2009.10a
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    • pp.647-650
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    • 2009
  • In recent years, an understanding and concern about the Photo Realistic CG increased while the CG industry grew. The overall understanding of a system, an output and algorithm, and etc. are needed in order to implement the Photo Realistic CG. Moreover, for the realistic output on CG, the texture task that it is logical the various environment condition according to the physical environment and time, and etc.s has to show. For carrying out the Photo Realistic CG texture task, the extensity of a texture, the physical properties, a material, and an environment, the various access and the logical analysis are needed. Analyzed data reaches the direct affect to the final product for expressing. The realistic ancient history site, and the cultural inheritance and industrial product will be implemented with the ground of the research of the upper part in the imaginary realistic world.

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A Study of Ten ding Diancibo Pu Characteristic (특정전자파(TDP)의 특성에 관한 고찰)

  • Bae Sung-Soo;Nam Sung-Woo;Kim Mi-Hyun
    • The Journal of Korean Physical Therapy
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    • v.11 no.2
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    • pp.5-9
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    • 1999
  • The electromagnetic agent used in physical therapy rely far their effects on tissue heating and photo reaction of the body, Infrared has a thermal and analgesic effect, Ultra violet produces direct photo chemical reaction when it interacts with the body. Laser has broad effect on medicine, Ten ding Diancibo Pu (TDP) is in the infrared ray. The wave range is 20,000-250,000, as a far infrared. The effects of the TDP are number of white and red blued cell, capacity of animal immunization activity of enzyme in the organ and blood sugar density.

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Physical properties of Silicon Dioxide Film Deposited on GaAs by Photo Excitation (GaAs기판위에 형성된 광여기 산화막의 물리적 특성)

  • Kwang Eui Pyun
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.26 no.8
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    • pp.1197-1202
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    • 1989
  • In this study, physical properties of silicon dioxide film deposited on GaAs by photo excitation are evaluated using ellisometry, ESCA and AES. Under the pressure of 2-8 torr, silicon dioxide film is deposited on GaAs by photo excitation at 200\ulcorner using gas mixtures of SiH4 and N2O. The measured results show refractive index varies from 1.37 to 1.42 and stoichiometry from 1.97 to 2.09 with process pressure. The observed characteristics of deposition rate are divided into three different regions with process pressure and possible deposition mechanism are also discussed, qualitatively.

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Gelation of silk fibroin solution via β-sheet formation promoted by riboflavin-mediated photo-crosslinking

  • Choi, Jaeho;Ki, Chang Seok
    • International Journal of Industrial Entomology and Biomaterials
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    • v.45 no.1
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    • pp.12-16
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    • 2022
  • Di-tyrosine photo-crosslinking of silk fibroin (SF) is recently highlighted as a biocompatible hydrogel fabrication process, because this method does not need potentially harmful chemical species. However, the resulting crosslinking density is often insufficient to obtain a mechanically stiff hydrogel unless additional oxygen is provided during the reaction. In this study, we proposed a combinational crosslinking method to form an SF hydrogel via the di-tyrosine photo-crosslinking with riboflavin (photoinitiator) and physical interaction of SF chains. In the UV light-irradiated SF solution, small particles formed and these particles promoted β-sheet formation of SF molecules, resulting in quick gelation. The di-tyrosine photo-crosslinking produced nuclei that might trigger regular assembly of SF molecules in high temperature condition. Conclusively, this process would contribute to a development of biocompatible hydrogel fabrication for biomedical uses of SF hydrogels.

Metal-insulator Transition of VO2 Thin Films and Nanowires Induced Photo-excitation

  • Sohn, Ahrum;Kim, Haeri;Kim, Eunah;Kim, Dong-Wook
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.196.1-196.1
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    • 2014
  • VO2 exhibits metal-insulator transition (MIT), of which critical temperature (TC) is about 340 K. There have been many reports that MIT can be induced by UV light as well as heat. Clear mechanism regarding such photo-induced MIT has not been clarified. We have compared the MIT behaviors of VO2 thin film during heating-cooling cycles with and without light. We tried several light sources with different wavelengths (red, blue, and UV). Tc and hysteresis width of the resistance change were influenced by the illumination of the samples. We performed Kelvin probe force microscopy (KPFM) studies, which can reveal the evolution of the local sample work function. In this presentation, we will discuss possible physical origins for the photo-induced effects on the MIT behaviors of the VO2 samples.

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Physical Properties of Light Cured Dental Composite Resin with Novel Photosensitizers (새로운 광증감제를 사용한 치과용 광중합형 복합레진의 기계적 특성)

  • Sun, Gum-Ju;Lee, Hee-Kyung
    • Journal of Technologic Dentistry
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    • v.35 no.4
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    • pp.313-320
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    • 2013
  • Purpose: The purpose of this study was to know the physical properties of UDMA dental composite resins containing two photosensitizers, PD, DA, as a photosensitizer instead of CQ. We want to know Remaining Double Bond(RDB) of UDMA unfilled resin and diametral tensile strength and flexural strength of composite resin containing PD and DA were compared with those of CQ, most widely used photosensitizer for dental composite resins. Methods: The RDB of UDMA studied by FT-IR spectroscopy increased with irradiation time. The composite resins were tested for their physical properties. The dental composite resins were made with UDMA as a monomer, silanized silica as filler, N,N-dimethylaminoethyl methacrylate (DAEM) as amine initiator, and one of the two kinds of new photosensitizers. Results: The relative RDB of UDMA was in the order: DA > CQ > PD but the physical properties of the composite resins show PD and DA with higher results compared with that containing CQ. The reason for the results is that PD and DA serve not only as a photosensitizer but also as a photo-crosslinking agent. Conclusion: PD and DA show as effective photosensizers, suitable for UDMA dental composite resin compare with a higher efficiency than CQ.

The Additive Effect of Polyoxyethylene Compounds on the Photographic Characters of Photographic Emulsion

  • Youn, Min-Young;Ahn, Hong-Chan;Kang, Tai-Sung
    • Journal of Photoscience
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    • v.7 no.2
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    • pp.45-46
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    • 2000
  • The polyoxyethylene compounds were added into the photographic emulsion during the physical ripening of photo sensitive silver halide crystal in this emulsion. The polyoxyethylene compounds improved the photographic properties of the film to a great extent increasing the photo sensitivity and decreasing the fog density.

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