• Current Optics and Photonics
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• 제5권3호
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• pp.278-288
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• 2021

We propose a characterization method for the scattering property of microspheres using spectroscopic optical coherence tomography (OCT). To prove the effectiveness of the proposed method, we prepare solutions of different concentrations using microspheres ranging from 28 to 2300 nm in diameter. Time-frequency analysis is performed on the measured interference spectrum of each solution, and the resulting spectroscopic information is converted into histograms for centroid wavelengths. The histograms present a very sensitive response to changes in the concentration and size of microspheres. We classify them into three categories according to their characteristics. When the histogram of each category is replaced with the corresponding calculated value of the scattering coefficient, each category is mapped to a different scattering-coefficient region. It is expected that the proposed method could be used to investigate the optical characteristics of a biological sample from OCT images, which would be helpful for optical diagnostic and therapeutic applications.

• 한국물환경학회지
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• 제23권6호
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• pp.863-871
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• 2007

Spectroscopic characteristics of river water from four major watersheds in the Ulsan area were measured to examine their potential for estimating water quality parameters. The total 176 river samples were collected from 44 sites of small streams within the watersheds during the year 2006. Spectroscopic characteristics investigated included protein-like fluorescence (FLF) intensity, fulvic-like fluorescence (FLF) intensity, terrestrial humic-like fluorescence (TLF) intensity, UV absorbance at 254 nm, and UV absorbance difference at 220 nm and 254 nm. Protein-like fluorescence intensity showed linear relationships with biochemical oxygen demand (BOD), chemical oxygen demand (COD), total phosphorous (TP) concentrations of the samples with the correlation of 0.784, 0.779, and 0.733, respectively. Due to the UV absorption characteristics of nitrate at 220 nm, UV absorbance difference at 220 nm and 254 nm was selected to represent total nitrogen (TN) concentration. Exclusion of some samples with PLF intensity higher than 5.0 improved the correlation between the UV absorbance difference and TN as demonstrated by the increase of the correlation coefficient from 0.392 to 0.784. Instead, for the samples with PLF intensity lower than 5.0, the highest correlation of TN was achieved with UV absorbance at 254 nm. The results suggest that PLF intensity could be used as the estimation index for BOD, COD, and TP concentration of river water, and as the primary screening index for the prediction of TN using UV absorbance difference. Some BOD-based water quality levels among the river water were statistically discriminated by the PLF intensity. Low p-values were obtained from the t-tests on the samples with the first level and the second level (p=0.0003) and the samples with the second and the third levels (p=0.0413). Our combined results demonstrated that the selected spectroscopic characteristics of river water could be utilized as a tool for on-site real-time monitoring and/or the primary estimation of water quality.

• Journal of Biosystems Engineering
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• 제40권1호
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• pp.67-77
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• 2015

Purpose: Fungal secondary metabolite (mycotoxin) contamination in foods can pose a serious threat to humans and animals. Spectroscopic techniques have proven to be potential alternative tools for early detection of mycotoxins. Thus, the aim of this review is to provide an overview of the current developments in nondestructive food safety testing techniques, particularly regarding fungal contamination testing in grains, focusing on the application of spectroscopic techniques to this problem. Methods: This review focuses on the use of spectroscopic techniques for the detection of fungi and mycotoxins in agricultural products as reported in the literature. It provides an overview of the characteristics of the main spectroscopic methods and reviews their applications in grain analysis. Results: It was found that spectroscopy has advantages over conventional methods used for fungal contamination detection, particularly when combined with chemometrics. These advantages include the rapidness and nondestructive nature of this approach. Conclusions: While spectroscopy offers many benefits for the detection of mycotoxins in agricultural products, a number of limitations exist, which must be overcome prior to widespread adoption of these techniques.

• 방사성폐기물학회지
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• 제5권2호
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• pp.103-108
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• 2007

질산, 불산 및 과염소산을 사용하여 플루토늄 옥사이드 $(PuO_2)$을 녹여 Pu 기준용액을 제조한후 UV-Visible-Near IR 분광기를 이용하여 Pu 흡수 스펙트럼 특성을 관찰하였다. 산성, 중성 및 알칼리 매질에서 Pu(III), Pu(IV) 및 Pu(VI)에 대한 분광학적 특성을 조사하였다. 또한 알칼리 및 산 농도 증가에 따른 Pu(VI) 흡수 스펙트럼에 대한 특성 피크 세기 및 위치를 관찰하였다. 염산 및 수산화나트륨 매질에서 환원제 첨가에 따른 Pu(VI) 산화수 변화를 측정하였다.

• 조명전기설비학회논문지
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• 제24권3호
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• pp.8-13
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• 2010

For better picture quality in LCD TVs, it is important to reach a steady emitting state within as short a time as possible in the initial stage after the TV is turned on. The initial characteristics of LCD TVs are mainly determined by the properties of the backlight. In the present study, the photometric and spectroscopic properties of a 55-inch Cold Cathode Fluorescent Lamp (CCFL) and Light Emitting Diode (LED) backlights were investigated. The measured properties include time dependence of the spectrum, luminance, and color coordinates. The results show that the change in the spectroscopic properties of the LED backlight is smaller than that of the CCFL backlight. This indicates that the initial picture quality of the LCD TV with the LED backlight is superior to that with the CCFL backlight. The origins of this difference were discussed in relation to the inherent characteristics of the two light sources.

• 천문학논총
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• 제15권spc1호
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• pp.85-91
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• 2000

Infrared spectroscopic observations and their analysis revealed many physical and chemical characteristics of the various stars with dust envelopes. Especially, AGB stars and young stellar objects are believed to be major contributors of infrared radiation from galaxies. The wavelength of the peak spectral energy for typical galaxies is about $100{\mu}m$. Therefore, infrared spectral observations of galaxies provide important information for their overall properties. The qualitative analysis of the infrared spectra which are made of various stars and interstellar matter will be possible through a new population synthesis.

• 한국인쇄학회지
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• 제13권1호
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• pp.73-91
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• 1995

Spectroscopic and Photoelectric Characteristics in the Cyanine and Merocyanine Dye according to systematically change of their structures were experimentally discussed. As result, in solution, Hetero atoms(X) of Cyanine and Merocyanine dye were participated in resonance X of d obital rather than X of pobital,effected in resonance and contributed in extension of conjugated system. in solid film,new spectra,called eximer-fluorenscence,were appeared in 3-dimensional fluorenscence of high density of Cyanine dye but not of Merocyanine. The activational energy of conductivity in Merocyanine dye was lower than in cyanine, an the contrary,the drift mobility was higher and the former in photoelectric characteristics was more effec-tive than the latter. In this paper,authors invertigated the changes of dye structure by molecular obital method to confirm the results of spectroscopic and photoelectric characteristics in the Cyanine and Merocyanine Dye acco-rding to systematically cally change of their structure, and counted total energy on dihedral angle and dipol miments if dyes in S0 and S1.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1932-1938
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• 2003

We have applied spectroscopic ellipsometry to investigate $high-{\kappa}$ dielectric thin films and correlate their optical properties with fabrication processes, in particular, with high temperature annealing. The use of high-k dielectrics such as $HfO_{2}$, $Ta_{2}O_{5}$, $TiO_{2}$, and $ZrO_{2}$ as the replacement for $SiO_{2}$ as the gate dielectric in CMOS devices has received much attention recently due to its high dielectric constant. From the characteristics found in the pseudo-dielectric functions or the Tauc-Lorentz dispersions, the optical properties such as optical band gap, polycrystallization, and optical density will be discussed.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.106-106
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• 2022

An appropriate amount of nitrogen fertilizer input during rice cultivation is essential for rice growth, quality control, and reduction of greenhouse gases in paddy fields. Therefore, it is necessary to develop a technology that can check whether an appropriate amount of fertilizer is applied in paddy fields. In this study, we tried to derive a method for diagnosing nitrogen fertilization level using spectroscopic diagnosis, physiological analysis, and molecular indicator genes. Nitrogen fertilization treatment was performed in a greenhouse by dividing into five treatment conditions: no fertilization (N0), low fertilization (N0.5), standard fertilization (N1.0), excessive fertilization (N1.5), and double fertilization (N2.0), respectively. Growth characteristics analysis was investigated by nitrogen fertilization conditions and growth stages, and the height of the canopy was analyzed using a laser scanner. Physiological and spectroscopic analyses were performed by analyzing chlorophyll and sugar contents and measuring SPAD and leaf spectrometer on rice leaves. In addition, real-time PCR experiment was performed to check the relative expression levels of several known nitrogen metabolism related genes. These results suggest that spectroscopic techniques can be helpful in diagnosing the level of nitrogen fertilization in rice paddy fields.

• 반도체디스플레이기술학회지
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• 제22권3호
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• pp.90-95
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• 2023

We describe an optimal alignment method for improving accuracy of dynamic spectroscopic polarimeter based on monolithic polarizing interferometer. The dynamic spectroscopic polarimeter enables real-time measurements of spectral ellipsometric parameters by using a spectral carrier frequency concept. However, the non-polarizing beam splitter used in the monolithic polarizing interferometer cannot maintain the polarization state perfectly due to phase retardation caused by optical anisotropic characteristics of the non-polarizing beam splitter, resulting in degraded measurement accuracy. The effect of the beam splitter can be minimized through optimal alignment of the polarizers used in the polarizing interferometer and the analyzer. We demonstrate how much the proposed alignment method can enhance the measurement accuracy by comparing with previous alignment approach.