• Journal of Food Hygiene and Safety
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• v.39 no.2
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• pp.61-71
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• 2024

In this study, we analyzed chlorogenic acid indicator components in preparation for the additional listing of green coffee bean extract in the Health Functional Food Code and optimized caffeine for simultaneous analysis. We extracted chlorogenic acid and caffeine using 30% methanol, phosphoric acid solution, and acetonitrile-containing phosphoric acid and analyzed them at 330 and 280 nm, respectively, using liquid chromatography. Our analysis validation results yielded a correlation coefficient (R²) revealing a significance level of at least 0.999 within the linear quantitative range. The chlorogenic acid and caffeine detection and quantification limits were 0.5 and 0.2 ㎍/mL and 1.4, and 0.4 ㎍/mL, respectively. We confirmed that the precision and accuracy results were suitable using the AOAC validation guidelines. Finally, we developed a simultaneous chlorogenic acid and caffeine analysis approach. In addition, we confirmed that our analysis approach could simultaneously quantify chlorogenic acid and caffeine by examining the applicability of each formulation through prototypes and distribution products. In conclusion, the results of this study demonstrated that the standardized analysis would expectably increase chlorogenic acidcontaining health functional food quality control reliability.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.8
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• pp.1162-1169
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• 2016

A new method based on accelerated solvent extraction (ASE) combined with response surface methodology (RSM) has been developed for optimization of the extraction of ginsenoside [Rb1, Rg1, and Rg3(20S)], total phenolics, and benzopyrene in red ginseng. The RSM method, based on a five level and two variable central composite design, was employed to obtain the optimal combination of extraction conditions. In brief, ginsenosides Rb1, Rg1, and Rg3(20S) and total phenolics with undetectable benzopyrene were optimally extracted with 50% ethanol as an extraction solvent, extraction temperature of $158^{\circ}C$, extraction time of 20 min, extraction pressure of 2,500 psi, flush volume of 60%, and one extraction cycle. The contents of ginsenosides and total phenolics in red ginseng extracted by ASE under optimum conditions were significantly higher than those extracted by sonication and reflux extraction.

• ETRI Journal
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• v.32 no.2
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• pp.319-326
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• 2010

Photonics offers a solution to data communication between logic devices in computing systems; however, the integration of photonic components into electronic chips is rather limited due to their size incompatibility. Dimensions of photonic components are therefore being forced to be scaled down dramatically to achieve a much higher system performance. To integrate these nano-photonic components, surface plasmon-polaritons and/or energy transfer mechanisms are used to form plasmonic chips. In this paper, the operating principle of plasmonic waveguide devices is reviewed within the mid-infrared spectral region at the 2 ${\mu}m$ to 5 ${\mu}m$ range, including lossless signal propagation by introducing gain. Experimental results demonstrate that these plasmonic devices, of sizes approximately half of the operating free-space wavelengths, require less gain to achieve lossless propagation. Through optimization of device performance by means of methods such as the use of new plasmonic waveguide materials that exhibit a much lower minimal loss value, these plasmonic devices can significantly impact electronic systems used in data communications, signal processing, and sensors industries.

• Bulletin of the Korean Chemical Society
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• v.35 no.5
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• pp.1391-1396
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• 2014

In the present study, ten metal free non-linear optical (NLO) compounds have been designed. These compounds have designed by structural modification of (2-cyano-5-(4-(phenyl(4-vinylphenyl)amino)phenyl) penta-2,4-dienoic acid (TC4). Density functional theory was used for structure optimization and determination of photo-physical properties. These compounds contain triphenylamine as electron-donor and cyanoacrylic acid as acceptor. Five ${\pi}$-spacers are used to connect the donor and acceptor. Two auxiliary donors are also used to assist the donor. Results of this study indicate that stronger electron-donating auxiliary groups and longer ${\pi}$-conjugation enhance NLO response. Major absorption peaks of all systems were in the visible region. These absorption peaks are associated with the ${\pi}-{\pi}^*$ transitions of the entire molecule. From calculations it is clear that all system will be good NLO material. The present calculations will provide new ways for experimentalists to synthesize high-performance NLO material.

• Proceedings of the IEEK Conference
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• 2004.06b
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• pp.577-580
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• 2004

Our paper focus on crosstalk noise problem, especially crosstalk glitch that occurs when victim is stable state and aggressor is transitive state. This generated glitch weigh with the functional reliability if the glitch is considerable. In this paper, we use buffer insertion, down sizing, buffer insertion with up-sizing methods concurrently. These methodologies use filtering effects which gates that have bigger noise margin than glitch width eliminates glitch. In addition, we do limited optimization in boundary of node's slack. Therefore, the operated node's changes are for nothing in other node's slack.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.10a
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• pp.45-49
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• 2001

The length and the breadth or a very large floating airport are determined by airplane types and airport facilities. However, the depth affect not only the structural strength but also the functional requirement such as a possibility of taking off and landing. The optimization problem for determining the depth is to select a design so that the cost is minimized. In this paper, a general arrangement and a method to decide the depth are proposed. Strength, functional requirement, and possibility of occurrence of deck wetness and slamming are considered in order to determine the depth of structure. Hydrodynamic forces of the diffraction and radiatin problems are predicted by applying the source-dipole distribution method, and the structural responses are obtained by the finite element method.

• Journal of the Korea Furniture Society
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• v.27 no.4
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• pp.309-317
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• 2016

Recently, Korean society is increaseing "1 person family" phenomenon, which is influenced by changing of young peoples' value, aging society and social economic problems. Increase of single households is a result of complex economic, cultural and social factors. It is because as the individual's financial independence increases due to elevated income and education level, the age of marriage is going up and the individualism, which values the individual's value rather than custom, is spreading. Therefore, this new phenomenon will be impact to between social, economic value structure and living space. An increase with small furnitures are also increasing of R&D and marketing plans for 1 person family. Currently, 1 person family is bigger than last decade and that is requiring more suitable and multi-functional furniture for them. However, in Korea furniture companies are more optimization to traditional family size. Thus, this research explore about developing cheap price sofa bed, which is using at narrow area and small place.

• Journal of Microbiology and Biotechnology
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• v.19 no.9
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• pp.966-971
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• 2009

Peroxidase from Coprinus cinereus (CiP) has attracted attention for its high specific activity and broad substrate spectrum compared with other peroxidases. In this study, the functional expression of this peroxidase was successfully achieved in the methylotrophic yeast Pichia pastoris. The expression level of CiP was increased by varying the microbial hosts and the expression promoters. Since a signal sequence, such as the alpha mating factor of Saccharomyces cerevisiae, was placed preceding the cDNA of the CiP coding gene, expressed recombinant CiP (rCiP) was secreted into the culture broth. The Mut Pichia pastoris host showed a 3-fold higher peroxidase activity, as well as 2-fold higher growth rate, compared with the $Mut^s $ Pichia pastoris host. Furthermore, the AOX1 promoter facilitated a 5-fold higher expression of rCiP than did the GAP promoter.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.1
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• pp.13-18
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• 2005

This paper considers a design problem of the repetitive control system for linear systems with time-varying norm bounded uncertainties. Using the Lyapunov functional for time-delay systems, a sufficient condition ensuring robust stability of the repetitive control system is derived in terms of an algebraic Riccati inequality (ARI) or a linear matrix inequality (LMI). Based on the derived condition, we show that the repetitive controller design problem can be reformulated as an optimization problem with an LMI constraint on the free parameter.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.433-434
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• 2008

In this paper, we present an improved design of the conventional ARM7 processor. It is based on the flip-flop to improve the pipeline performance of the processor. Also for improving the performance, the optimization of functional blocks and a multiplier is carried out. According to the experimental results, the maximum delay-time of functional blocks and the execution cycle of a multiplier is reduced by 33% and 2 cycles compared with a conventional design, respectively. Therefore, it leads to improve an operation speed about 30%.