• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 봄 학술발표회 논문집
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• pp.388-399
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• 2003

Light losses in optical fibers are investigated by a fiber optic OTDR (Optical Time Domain Reflectometry) sensor system to develop fiber optic probes for structural strain measurement. The sensing fibers are manufactured 3 kinds of fibers: one is single mode fiber, and second is multimode fiber, and the third is low-cladding-index fiber. Fiber bending tests are performed to determine the strain sensitivity according to the strain of gage length of optical fibers. In the result of this experiments, the strain sensitivity of the single mode fiber was shown the highest value than others. The fiber optic strain probe was manufactured to verify the feasibility of the structural strain measurement. In this test, the fiber optic strain probe of the OTDR sensor could be easily made by the single mode fiber.

• Bulletin of the Korean Chemical Society
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• 제35권3호
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• pp.941-944
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• 2014

• 천문학회보
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• 제37권2호
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• pp.76.2-76.2
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• 2012

We present the first simulations of cosmic reionization that include the first stars and their radiative feedback that limited their formation, in a volume large enough to capture the spatial variations that affected the process and its observability. We show hat these first stars made reionization begin much earlier than without, and was reatly extended, which boosts the intergalactic electron-scattering optical depth and the large-angle polarization fluctuations of the cosmic microwave background (CMB) significantly. Although within current WMAP uncertainties, this will enable Planck see he signature of the first stars at high redshift, currently undetectable by other probes.

• Applied Science and Convergence Technology
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• 제26권6호
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• pp.195-200
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• 2017

A mobile lab kart for plasma training is developed with a high vacuum pumping system, vacuum gauges and a glass discharge tube powered by a high voltage transformer connected to a household 60 Hz line. A numerical model is developed by using a commercial multiphysics software package, CFD-ACE+ to analyze the experimental data. Simulations for argon and nitrogen were carried out to provide fundamental discharge characteristics. Variations of the kart configuration were demonstrated: a glass tube with three electric probes, optical emission spectrometer attachment and infra red thermal imaging system to give more detailed analysis of the discharge characteristics.

• 열처리공학회지
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• 제23권4호
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• pp.205-209
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• 2010

Transparent and conductive AZO films were deposited on the glass by using radio frequency (RF) magnetron sputtering with intense electron radiation, simultaneously. After deposition, the effect of electron radiation energy on the optical and electrical properties of AZO was investigated. In XRD measurements, the films irradiated with intense electron beam show the larger grain size than that of the films prepared without electron radiation. Sheet resistance was also dependent on the electron radiation energy, while the optical transmittance in visible wavelength region was not affected seriously by electron radiation. X-.ray diffraction, UV-Vis spectrophotometer and four point probes were used to observe the crystallization, optical transmittance and sheet resistance, respectively.

• Journal of the Optical Society of Korea
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• 제13권1호
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• pp.166-170
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• 2009

NIRS (Near-infrared spectroscopy) is a relatively, new, non-invasive, and non-ionizing method of measuring hemodynamic responses in thick biological tissues such as the cerebral cortex. In this study, we measured the hemodynamic responses of the rat barrel cortex to whisker stimulation by using a frequency-domain NIRS system. We designed multiple optical probes comprising multi-mode optical fibers and manipulating arms, both of which can be easily applied to small animals. Various electrical stimulations were applied to rat whiskers at different voltage levels and stimulation frequencies. Our results show that the hemodynamic responses are highly dependent on the stimulation voltage level, and not so much on stimulation frequency. This paper suggests that NIRS technology is highly suitable for the study of small animal brains.

• 공업화학
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• 제32권1호
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• pp.1-9
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• 2021

알츠하이머병은 신경퇴행질환으로 뇌조직에서 발생하는 아밀로이드 베타(amyloid-β, Aβ) 펩타이드의 축적과 응집, 타우 단백질의 초인산화, 고농도의 특정 금속이온 축적에 의해 발병하는 것으로 알려져 있다. 현재까지 효과적인 치료제가 개발되지 못하였기 때문에, 알츠하이머병을 초기에 정확하게 진단하는 기술은 매우 중요하다. 알츠하이머병의 진단을 위해 개발된 다양한 기법 중 형광 프로브를 이용한 알츠하이머병의 바이오마커 영상화는 많은 연구자들의 관심을 받고 있다. 본 리뷰 논문에서는 최근 개발된 알츠하이머병 진단용 형광 프로브의 구조와, 체내 뇌 영상화에의 적용을 소개하고자 한다. 본 논문은 향후 새로운 프로브를 개발하고자 하는 연구자들에게 많은 도움이 될 것으로 기대된다.

• 세라미스트
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• 제10권3호
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• pp.55-66
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• 2007

Infrared Scanning Near-field Optical Microscopy (IR-SNOM) is an extremely powerful analytical instrument since it combines IR spectroscopy's high chemical specificity with SNOM's high spatial resolution. In order to do this in the infrared, specialty chalcogenide glass fibers were fabricated and their ends tapered to generate SNOM probes. The fiber tips were installed in a modified near field microscope and both inorganic and biological samples illuminated with the tunable output from a free-electron laser located at Vanderbilt University. Both topographical and IR spectral images were simultaneously recorded with a resolution of ${\sim}50\;nm$ and ${\sim}100\;nm$, respectively. Unique spectroscopic features were identified in all samples, with spectral images exhibiting resolutions of up to ${\lambda}/60$, or at least 30 times better than the diffraction limited lens-based microscopes. We believe that IR-SNOM can provide a very powerful insight into some of the most important bio-medical research topics.

• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2000년도 춘계학술대회 논문집
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• pp.150-151
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• 2000

Some chromophores that can undergo a pronouncend colour change when acted upon an extenal agency, such as light, heat, pH, or chemical agents, have many potential applicationa as functional dyes. They may be used as indicators, optical sensors, biochemical probes, optical and thermal recording materials. The results will investigate donor-acceptor chromophores which have the potential for such colour change processes. In particular, cross-conjugated donor-acceptor chormophores, analogous to indigo and squarylium-type chromophores, will be examined for pH sensitizing and for their oxidation-reduction colour change behaviour.

• 한국염색가공학회지
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• 제26권1호
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• pp.7-12
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• 2014

Nowdays, fluorescent rhodamine chemosensors have attracted a worldwide interest due to its ability to selectively detect heavy and transition metal cations. Due to the importance in environmental and biological toxic effects, the developments of fluorescent chemosensors have been received considerable attention in recent. Especially, a rhodamine-based chemosensor probes have been proved to be useful by exhibiting the efficient "off-on" fluorescence switching toward selected metal cations. This fluorophore can undergo the transformation from non-fluorescent and colorless spirolactam derivative to fluorescent ring-open form. In this study, a new fluorescent chemosensor was synthesized using rhodamine B through two-step procedures, and its selectivity and related optical property were characterized. Selectivity and sensitivity was found toward $Cu^{2+}$ guest molecules and then related optical properties of rhodamine B based fluorescent chemosensor compound were characterized using discussed. In addition, computational calculation was used to determine the HOMO/LUMO values.