• Proceedings of the PSK Conference
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• 2002.10a
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• pp.401.2-401.2
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• 2002

To study the pharmacokinetics of triflusal, more reliable and sensitive analytical method of triflusal in plasma sample was developed. Analytical method of triflusal in human plasma was developed using semi-microbore HPLC equipped with automated column switching system. p- Toluic acid, which is structural analogue of triflusal. was used as an internal standard and 2 M HCI was employed as a stabilizer. The load phase and mobile phase were prepared using acetonitrile and 20 mM $KH_{2}PO_{4}$ with the volume ratios of 10:90 (pH 2.5) and 43:57 (pH 2.3), respectively. (omitted)

• Journal of Environmental Health Sciences
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• v.36 no.6
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• pp.510-517
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• 2010

Phthalates, such as di (2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP) have been proved to be teratogenics and endocrine disruptors, metabolized rapidly and excreted in the urine. In this study, a simultaneous analytical method for 10 phthalate metabolites, MnBP, MiBP, MBzP, MCHP, MEHP, MEHHP, MEOHP, MnOP, MiNP and MiDP, in human urines, based on switching system with on-line pretreatment column using HPLC-MS/MS has been developed. This method was validated according to the guideline of bioanalytical method validation of National Institute of Toxicological Research. Limits of detection range between 0.2 and 0.9 ng/ml for 10 phthalate metabolites. The calibration curves showed linearity in the range 0.997~0.999, and the results of the intra- and inter-day validations were in the range from 0.4 to 14.7% RSD and from 0.3 to 9.4% RSD, respectively. Recoveries of phthalate metabolites varied from 87.0 to 116.1%. This analytical method showed high accuracy and stable precision for all metabolites, and seems to be suitable for biomonitoring of phthalates in human urine.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1531-1534
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• 2009

Effect of process factors on the sensitivity of inner-type digital switching TSP was analyzed. From these results, we have successfully fabricated inner-type digital switching TSP embedded in 3.2-inch WQVGA PLS mode LCD panel. During many factors, TFT sensor structure for reducing the PI thickness and a separation distance of $0.3{\mu}m$ between the conductive column spacer (C/S) and TFT sensor were essential. Glass thickness and main C/S density were also important factors. This technology can be applied to wide angle of view hand-held phones, personal digital assistants (PDAs), and tablet PCs.

• Proceedings of the PSK Conference
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• 2000.04a
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• pp.217.3-218
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• 2000

• Proceedings of the Korean Society of Applied Pharmacology
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• 2002.07a
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• pp.216-216
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• 2002

• Proceedings of the PSK Conference
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• 2002.04a
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• pp.219.1-219.1
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• 2002

• Korean Journal of Veterinary Service
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• v.29 no.3
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• pp.339-346
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• 2006

Semi-micro-HPLC using a column-switching technique was developed for simultaneous determination of vitamin A and E contents in infant formula. Vitamin A and E were extracted by PDA - HPLC with reversed phase column using organic solvent and their contents in Certified Reference Material (CRM) and infant formula were determined and compared with hydrolysis method and rapid extraction. Developed method has many advantages of simple and rapid sample preparation and simultaneous determination of vitamin A and E by micro-HPLC using reversed phase column.

• Industrial Engineering and Management Systems
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• v.3 no.2
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• pp.92-99
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• 2004

We consider the ATM switching node location problem (ANLP). In this problem, there are two kinds of facilities, hub facilities and remote facilities, with different capacities and installation costs. We are given a set of customers with each demand requirements, a set of candidate installation sites of facilities, and connection costs between facilities. We need to determine the locations to place facilities, the number of facilities for each selected location, the set of customers who are connected to each installed hub via installed remote facilities with minimum cost, while satisfying demand requirements of each customer. We formulate this problem as a general integer programming problem and solve it to optimality. In this paper, we present a preprocessing procedure to tighten the formulation and develop a branch-and-price algorithm. In the algorithm, we consider the integer knapsack problem as the column generation problem. Computational experiments show that the algorithm gives optimal solutions in a reasonable time.

• Analytical Science and Technology
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• v.28 no.2
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• pp.125-131
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• 2015

A method was developed and fully validated for the determination of terbutaline, a β₂-receptor agonist, in human plasma. Plasma samples were prepared by solid-phase extraction with Sep-Pak silica, followed by high-performance liquid chromatography (HPLC). The terbutaline was pre-separated from the interfering components in plasma on a Luna C18 (2) column, and terbutaline and salbutamol as an internal standard were resolved and determined on a Luna Silica column. The two columns were connected by a switching valve equipped with silica pre-column. The pre-column was used to concentrate the terbutaline in the eluent from the C18 column before back-flushing onto the silica column with fluorescence detection at an excitation/emission wavelength of 276/306 nm. The method was shown to be specific by testing six different human plasma sources. Linearity was established for a concentration range of 0.4-20.0 ng/mL with a correlation coefficient of 0.9999. The lower limit of quantitation was 0.4 ng/mL with a precision of 10.1% as C.V.%.

• Asian Journal of Atmospheric Environment
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• v.5 no.3
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• pp.146-151
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• 2011

1-Nitropyrene (1-NP), 2-NP and 2-nitrofluoranthene (2-NFR) are useful markers for studying the atmospheric behaviors of polycyclic aromatic hydrocarbons (PAHs) and nitropolycyclic aromatic hydrocarbons (NPAHs). However, present methods for measuring trace levels of these compounds are lesssensitive and laborious. Here we describe several improvements to a previously reported high-performance liquid chromatography-chemiluminescence detection system that allows it to determine trace levels of 1-, 2-NPs and 2-NFR. The proposed system was equipped with a reducer column packed with Pt/Rh instead of zinc whose life-time was limited. The combination of Cosmosil MS-II (monomeric ODS) and AR-II (polymeric ODS) columns was used instead of polymeric ODS columns as the separator column to improve the separation. An ethanol mixture with acetate buffer (pH 5.5) was used in place of an acetonitrile mixture with the same buffer to activate the reducer column. The same ethanol mixture was used as the mobile phase for the clean-up column. The switching time of the column switching valve was optimized to concentrate the amino-derivatives of above NPAHs quantitatively on the concentrator column. The concentrations of bis(2,4,6-trichlorophenly) oxalate and hydrogen peroxide in the chemiluminescence reagent solution were optimized to 0.4 mM and 30 mM, respectively, to increase the sensitivity. Under the above conditions, the detection limits (S/N=3) of 1-, 2-NPs and 2-NFR were 1 fmol (0.25 pg), 10 fmol (2.5 pg) and 4 fmol (1 pg), respectively. The proposed system was effectively used to determine trace levels of 1-, 2-NPs and 2-NFR in airborne particulates collected at Noto Peninsula. The atmospheric concentrations of 1-, 2-NPs and 2-NFR were not more than sub pg $m^{-3}$ levels. They were higher in winter (January) than in summer (July). In both seasons, the concentrations were in decreasing order, [2-NFR]>[1-NP]>[2-NP].