• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.631-635
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• 1993

This paper shows the procedure to determine the physical variables of the simple synthetic testing facility using LC resonance circuit and presents the calculated results of those variables for the LC resonance circuit which can be used to test circuit breakers up to 36kV 40kA class. Attention has also been paid to the advantages of the LC resonance circuit compared with the method adopting short-circuit generator for the development of circuit breakers.

• Korean Journal of Veterinary Service
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• v.25 no.3
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• pp.221-227
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• 2002

This study was carried out to confirm analytical method of residual macrolides in livestock products by LC/MS. 1. Macrolides were analyzed by LC/MS on XTerra C$\sub$18/ column with 0.1% TFA(trifluoroacetic acid)-methanol in a gradient mode as mobile phase, and that were identified by positive chemical ionization with selective ion monitoring at 50～1000 mass range. 2. Residual macrolides were extracted from tissue with acetonitrile, and the extract is purified with a Sep-pak C$\sub$18/ cartridge, and elute macrolides with 0.1M methanolic ammonium acetate. 3. The procedure confirms the presence of each macrolide at 50$\mu\textrm{g}$/kg in spiked sample.

• Biomolecules & Therapeutics
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• v.8 no.3
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• pp.235-240
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• 2000

Antitumor effect of LC43, a protein-bound ploysaccharide (M.W. 43 kDa) that was purified from intergeneric protoplast fusant of Lentinus edodes and Coriolus versicolor, was elucidated against mouse sarcoma 180 cell in vitro and in vivo. By injecting LC43 into ICR mice bearing solid or ascitic sarcoma 180, tumor regression and survival rates were investigated. To examine the effects of LC43 on immunopotentiation activity. immunoorgan weight, B cell differentiation, T cell activity and macrophage activation were determined. LC43 showed antitumor effects against both solid tumor and ascitic tumor of sarcoma 180. It did not change significantly the immunoorgan weight but potentiated immune responses such as B cell differentiation and the release of superoxide anion from macrophages. These results suggest that the protein-bound polysaccharide of LC43 exhibited antitumor activities through the activation of immune-related cells and acted as an immunmodulator.

• Proceedings of the KIPE Conference
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• 2010.11a
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• pp.198-199
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• 2010

In this paper, bi-directional DC/DC converter using a LC series resonant converter is proposed. A proposed converter is consisted by adding LC series resonant tank into a conventional bi-directional DC/DC converter and performs soft-switching at both boost and buck mode. A LC series resonance occurs in whole operation mode and switching point is determined by specific condition. Through the theoretical analysis and simulation results, operation modes and characteristics of the proposed topology is verified.

• Mass Spectrometry Letters
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• v.10 no.3
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• pp.84-87
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• 2019

Liquid chromatography mass spectrometry is widely employed in proteomics studies. One of such instruments is the Liquid Chromatography (LC)-Matrix-assisted laser desorption ionisation (MALDI)-Time of flight (TOF) or LC-MALDI-TOF/TOF. In this study, this instrument was used to identify the membrane proteins of a protozoan parasite namely Entamoeba histolytica. It causes amoebiasis in human. The E. histolytica trophozoites were cultured prior to the membrane protein extraction using the conventional method, $ProteoPrep^{(R)}$ and $ProteoExtract^{(R)}$ kits. Then, the membrane protein extracts were trypticdigested and analysed by LC-MALDI-TOF/TOF. Approximately, 194 proteins were identified and 27.8% (54) were predicted as membrane proteins having 1 to 15 transmembrane regions and signal peptides by combining all three extraction methods. Also, this study has discovered 3 unique proteins as compared to our previous study which merit further investigation.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.6
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• pp.411-420
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• 2021

In this paper, bidirectional LLC-LC resonant DC-DC converter with notch filters in the primary side of resonant circuits is proposed. Even if resonant capacitors are used on the primary and secondary sides, the proposed converter can operate with the high gain characteristics of the LLC resonant converter without mutual coupling of resonant capacitors, regardless of the direction of power flow. In addition, by applying notch filters, the proposed converter can operate with a wider gain control range and can cope with overload and short circuit. The analysis and operating characteristics of the proposed bidirectional LLC-LC resonant converter are investigated. A 3.3 kW prototyped bidirectional LLC-LC resonant converter connected to 750 V_DC buses is designed and tested to verify the validity and applicability of this proposed converter.

• Journal of Information Display
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• v.2 no.3
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• pp.32-38
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• 2001

The most important parameter for TV application of LCD is a fast switching time for the display of moving image. To achieve faster switching time, the novel LC single materials with large dielectric anisotropies ($16{\sim}20$), high clearing temperatures ($195.5{\sim}237.4^{\circ}C$), broad nematic ranges (up to 169.9 $^{\circ}C$) and high birefringence ($0.254{\sim}0.2200$) were developed. KUR-series LC mixtures blended these single materials having significantly higher clearing temperatures and dielectric anisotropy values compared with conventional LC mixture. Especially, their clearing temperatures are $10{\sim}30^{\circ}C$ higher than their host mixture. These LC mixtures showing about lOms of high-speed switching time in Tv/Monitor of TFT LCD, is short enough to be addressed in a single time frame of 60Hz (16.7 ms). The threshold voltage $V_{th}$ was low enough to operate at a driving voltage of 5 V. The VHR values were found to be high enough for TFT-LCD in wide temperature range. Our novel LC mixtures are suitable materials for the inclusion in to LC mixtures for TV application of TN-LCD

• The Journal of Internal Korean Medicine
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• v.36 no.3
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• pp.217-227
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• 2015

Objectives: The primary aim of this study was to identify bioactive compounds in Dangnyo-hwan, a Korean herbal medicine, through instrumental analysis using LC-MS/MS and ICP, and investigate its potential use in diabetes treatment. Methods: The extract of Dangnyo-hwan has 12 medicinal herbs; these were compared with 18 marker substances selected from literature survey. Results: LC-MS/MS analysis could detect 9 of the 18 bioactive compounds: citruline, catalpol, berberine, ginsenoside Rb1, ginsenoside Rg1, oleanolic acid, β-sitosterol, mangiferin, and schizandrin. While harmful heavy metals such as As, Pb, Cd, Hg, Ni, and Cu were not present in high concentrations, Zn concentration was 4.2 mg in 100 g Dangnyo-hwan. Conclusions: Instrumental analysis such as LC-MS/MS and ICP was successfully used to identify bioactive compounds in Dangnyo-hwan. Detection of 9 bioactive substances and Zn from the herb medicine is a valuable finding, and suggests that Dangnyo-hwan is a candidate medicine for diabetes. Further investigations like in vitro assay, percent GPR 119 activity, and percent human DGAT-1 inhibition are underway.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1589-1596
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• 2015

A novel control method of a three-phase PWM inverter with LC filter is proposed. The transfer function of LC filter is the same as that of 2nd order low pass filter(2nd LPF) which has a zero damping ratio. A simple method of implementing 2nd LPF with damping ratio is to add resistor to inductor or capacitor of LC filter. In an industrial application, it is not practical to adopt damping resistor because it results in losses being proportional to square of current flowing through resistor. Instead of using damping resistors, the proposed active damping control(ADC) utilizes all pass filter(APF) and considers inherent processing delay of digital controller. The overall transfer function of the proposed method is the same as a 2nd LPF and its damping ratio is also controllable via control variables. Detailed design and implementation of controller is also presented. Experiments are conducted with a 7.5kVA induction motor drive system controlled by PWM converter and inverter. Test waveforms are also presented to verify the proposed LC filter control algorithm.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.11
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• pp.2860-2870
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• 1994

When crack are detected in aged turbine rotors of power plants, information on fracture resistance of the aged material at operating temperature is needed for determination of critical loading condition and residual life of the turbine. In this study, fracture toughness (J$_lc$) and tearing modulus(T$_mat$) of virgin and thermally degraded 1Cr-1Mo-0.25V steel, which is one of the most widely used rotor steels, were measured at 538.deg. C according to ASTM E813 and ASTM E1152, respectively. Five kinds of specimen with different degradation levels were prepared by isothermal aging heat treatment at $630^{\circ}C.$ It was observed that J$_lc$ and T$_mat$ value decreased as the degradation level increased. Analysis of microstructures using a scanning electron microscope showed that the decrement of J$_lc$ is related to segregation of impurities at grain boundaries. It was also verified that the DC electric potential drop method is accurate and reliable for crack length monitoring at elevated temperature.