• Proceedings of the PSK Conference
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• 2003.04a
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• pp.278.2-278.2
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• 2003

A column-switching semi-micro HPLC method with fluorescence detection was developed for the direct analysis of rebamipide in human plasma. Plasma was filtered through a 0.45 $\mu\textrm{m}$ membrane filter and 5 ${\mu}\ell$ of the filtrate was directly injected onto the pre-column. After elution of the plasma proteins to waste, the retained rebamipide and internal standard(ofloxacin) were transferred to a C18 semi-microcolumn (5$\mu\textrm{m}$, 150 ${\times}$2.0mm) where they were separated using acetonitrile-1.4％ acetic acid (40:60, v/v) as mobile phase. (omitted)

• Journal of the Korean Society for Precision Engineering
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• v.13 no.12
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• pp.54-62
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• 1996

To get the time response characteristics of the hydrostatic transmission, seaborne winch is modelde by using bond graphs. After modeling of its basic elements, it is represented as power flow, and the determination of variable causality. The state equations are derived by using CAMP. As dynamic stabilites and solutions are investigated by perturbation method and direct integration, winch system is stable. Simulations are performed under the conditions of low speed, high speed, and maximum tension. The pressure and flow rate of the hydrostatic transmission have a big overshoot. But when it is comparaed to the empirical data with simulation results, it is similar to each other. When a lead compensator is applied to improve response characteristics of the hydrostatic transmission, rise time and overshoot of the system are improved.

• Communications for Statistical Applications and Methods
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• v.31 no.3
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• pp.337-347
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• 2024

Kernel density estimation is a prevalent technique employed for nonparametric density estimation, enabling direct estimation from the data itself. This estimation involves two crucial elements: selection of the kernel function and the determination of the appropriate bandwidth. The selection of the bandwidth plays an important role in kernel density estimation, which has been developed over the past decade. A range of methods is available for selecting the bandwidth, including the plug-in bandwidth. In this article, the proposed plug-in bandwidth is introduced, which leverages shifted Chebyshev series-based approximation to determine the optimal bandwidth. Through a simulation study, the performance of the suggested bandwidth is analyzed to reveal its favorable performance across a wide range of distributions and sample sizes compared to alternative bandwidths. The proposed bandwidth is also applied for kernel density estimation on real dataset. The outcomes obtained from the proposed bandwidth indicate a favorable selection. Hence, this article serves as motivation to explore additional plug-in bandwidths that rely on function approximations utilizing alternative series expansions.

• Journal of Biosystems Engineering
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• v.35 no.5
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• pp.343-349
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• 2010

Rapid on-site sensing of nitrate-nitrogen and potassium ions in hydroponic solution would increase the efficiency of nutrient use for greenhouse crops cultivated in closed hydroponic systems while reducing the potential for environmental pollution in water and soil. Ion-selective electrodes (ISEs) are a promising approach because of their small size, rapid response, and the ability to directly measure the analyte. The capabilities of the ISEs for sensing nitrate and potassium in hydroponic solution can be affected by the presence of other ions such as calcium, magnesium, sulfate, sodium, and chloride in the solution itself. This study was conducted to investigate the applicability of two ISEs consisting of TDDA-NPOE and valinomycin-DOS PVC membranes for quantitative determinations of $NO_3$-N and K in hydroponic solution. Nine hydroponic solutions were prepared by diluting highly concentrated paprika hydroponic solution to provide a concentration range of 3 to 400 mg/L for $NO_3$-N and K. Two of the calibration curves relating membrane response and nutrient concentration provided coefficients of determination ($R^2$) > 0.98 and standard errors of calibration (SEC) of < 3.79 mV. The use of the direct potentiometry method, in conjunction with an one-point EMF compensation technique, was feasible for measuring $NO_3$-N and K in paprika hydroponic solution due to almost 1:1 relationships and high coefficients of determination ($R^2$ > 0.97) between the levels of $NO_3$-N and K obtained with the ion-selective electrodes and standard instruments. However, even though there were strong linear relationships ($R^2$ > 0.94) between the $NO_3$-N and K concentrations determined by the Gran's plot-based multiple standard addition method and by standard instruments, hydroponic $NO_3$-N concentrations measured with the ISEs, on average, were about 10% higher than those obtained with the automated analyzer whereas the K ISE predicted about 59% lower K than did the ICP spectrometer, probably due to no compensation for a difference between actual and expected concentrations of standard solutions directly prepared.

• Analytical Science and Technology
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• v.12 no.4
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• pp.299-305
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• 1999

The electrolyte cathode atomic glow discharge (ELCAD) is a new plasma source for direct determination of trace heavy metals in drinking and waste water. ELCAD has been successfully developed for on-line monitoring of heavy metals, however, shows difficulty to measure mercury. In this study, ELCAD has been modified to apply the atomic absorption spectrometry (AAS) for the direct determination of trace elements of mercury in flowing water.The fundamental characteristics of this new types of plasma source have been investigated and found that the pH of the solution, discharge voltage, and current are most important factors.The absorbance of 1.0 ppm Hg standard solution increases as pH of the solution increases from pH 1.0 to 3.0.However, % RSD of the absorbance also increases as the pH of solution increasesdue to plasma unstability.The detection limits of the standard solution of pH 1.5 and pH 3.0 are about 40 ppb and 10 ppb level, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.16 no.3
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• pp.49-54
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• 1987

Procedures for Dietary Fiber(DF) determination were applied to some common vegetables. The samples selected in this study were: Radish(Leaf), Chinese cabbage, Spinach, Shepherd's purse, Red pepper(Leaf), Perilla(Leaf), Soybean(Leaf) and Cabbage. DF was analyzed by the method of detergent fractionation. Values for NDF, ADF, Lignin, Hemicellulose, Cellulose were obtained. NDF for most samples was $12.9{\sim}27.4%$, except Soybean(Leaf) (41.9%), ADP was $7.7{\sim}16.9%$. Lignin was around $1.0{\sim}2.1%$; Red pepper (Leaf) (7.6%), Perillar(Leaf) (5.7%), Soybean(Leaf) (4.2%) were exceptions. $Hemicellulose(NDF{\sim}ADF)$ was about $2.9{\sim}12.0%$, except Soybean(Leaf) (25.0%). $Cellulose(ADF{\sim}Lignin)$ was $6.3{\sim}13.0%$. This paper describes two properties of the fiber of commonly eaten vegetables; Water-Holding Capacity(WHC) and Density. The capacity of the ADP to hold water was estimated. The WHC measurements differed from 6.6g per g of ADP for Red pepper(Leaf) to 10.4g per g of ADP for Radish(Leaf). Radish(Leaf), Soybean(Leaf) had the greatest WHC whereas Red pepper(Leaf), Perillar(Leaf) had the least. Two types of density determinations are shown. Direct (non-packed) values largely correspond with bulk(packed) density.

• Korean Journal of Social Welfare Studies
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• v.42 no.2
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• pp.493-523
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• 2011

This study set out to investigate the effects of individual motivation on turnover intention among social workers and examine their turnover intentions in details by focusing on the mediation effects of multiple commitment. To be specific, it aimed to propose and test a prediction model for social workers' turnover intentions based on the Self-determination Theory and Theory of Planned Behavior. For those purposes, a mail survey was taken among social workers working for use facilities, residential facilities, public health centers, social welfare foundations and associations, and all kinds of centers and institutions in 15 cities and provinces across the nation. Total 1,918 questionnaires were distributed, and 1,671 ones were returned, and 979 whose respondents expressed a turnover intention were used in final analysis. The analysis results indicate that psychological motivation of social workers had direct impacts on their turnover intention. However, their role stress had no direct impacts on their turnover intention, which suggests that the impulsive routes model for turnover intention is supported only in psychological motivation and job characteristics. Secondly, their psychological and job motivation turned out to have indirect impacts on turnover intention through the multiple commitment, which suggests that the reflective routes model for turnover intention is supported in all career, job, and organizational commitment. Career commitment had the most significant impacts on turnover intention, being followed by job commitment and organizational commitment in the order, which suggests that the social welfare academy should increase their interest in career commitment. Based on the findings, the study proposed implication for the career management plans, plans for human resources

• Analytical Science and Technology
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• v.18 no.5
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• pp.403-409
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• 2005

Polycyclic Aromatic Hydrocarbons(PAHs) contamination arises from several sources including processing of food(smoking, direct drying, cooking) and environmental contamination of air, water, or soil, the later being considered as the most important. In this study, to establish the analytical method for some PAHs[benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, dibenzo(a,h)anthracene, benzo(g,h,i)perylene, indeno(1,2,3-c,d)pyrene] in fish, alkali digestion time, extraction solvents, elution volume of florisil cartridge for clean-up have been optimized. The methodology involved saponification and extraction with n-hexane, clean-up on Sep-Pak florisil cartridges and determination by HPLC/FLD(High Performance Liquid Chromatography/Fluorescence Detector). Overall method recoveries for 8 PAHs spiked into these products ranged from 90 to 106%.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.259-263
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• 2006

A direct HPLC method was used to analyze determination of resveratrol in grapes and wines. Content of resveratrol in different parts of 13 grape cultivars and 13 wines were quantified. The average total resveratrol content was $143.5{\mu}g/g$. Resveratrol contents in the skin, fruit, seed and fruit stem were distributed range of $0.9{\sim}104.8{\mu}g/g,\;0.1{\sim}0.5{\mu}g/g\;1.7{\sim}173.9{\mu}g/g\;2.9{\sim}247.4{\mu}g/g$, respectively. Resveratrol contents in 13 wines were distributed range of $253.3{\sim}11,271.6{\mu}g/g$.

• Korean Journal of Food Science and Technology
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• v.24 no.4
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• pp.393-395
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• 1992

The ${\alpha}-lactalbumin({\alpha}-la)$ concentration in raw and laboratory-heated milks by HPLC was 1.20 mg/ml (unheated), 1.17 mg/ml ($63^{\circ}C$, 30min), 1.13 mg/ml ($72^{\circ}C$, 15sec) and 0 mg/ml ($100^{\circ}C$, 10min), respectively. Whereas, ${\alpha}-lactalbumin$ concentration ranges of commercial milks were $1.00{\sim}1.02\;mg/ml$ (pasteurized), $0.23{\sim}0.68\;mg/ml$ (UHT-pasteurized) and $0.77{\sim}0.89\;mg/ml$ (UHT-sterilized), respectively. It was supposed that the ${\alpha}-lactalbumin$ content of sterilized milk will be lower than that of UHT milk, but the opposite occurred. This discrepancy would be caused by the different heating system in the milk plants, where indirect UHT-treatment had more heat intensity than direct UHT-processing. The HPLC determination of ${\alpha}-lactalbumin$ may be an indicator to evaluate correctly and rapidly heated milks.