• Proceedings of the KIPE Conference
• /
• 2001.10a
• /
• pp.301-303
• /
• 2001

In this paper we present a Capacitor Charging Power Supply (CCPS) using a series-resonant three-level inverter topology to improve voltage regulation and use semiconductor switches having low blocking voltage capability such as MOSFETs. This inverter can be operated with two modes, Full Power Mode (FPM) and Half Power Mode (HPM). In FPM inverter supplies the high frequency step up transformer with full DC-link voltage and in HPM with half DC-link voltage. HPM switching method will be adopted when CCPS output voltage reaches the preset target value and operates in refresh mode-charge is maintained on the capacitor. In this topology each semiconductor devices blocks a half of the DC-link voltage[2]. A 15kW, 30kV CCPS has been built and will be tested for an electric precipitator application. The CCPS operates from an input voltage of 500VDC and has a variable output voltage between 10 to 30kV and 1kHz repetition rate at 44nF capacitive load [3]. A resonant frequency of 67.9kHz was selected and a voltage regulation of $0.83\%$ has been achieved through the use of half power mode without using the forced cut off the switch current [1]. The theory of operation, circuit topology and test results are given.

• Journal of radiological science and technology
• /
• v.11 no.1
• /
• pp.33-41
• /
• 1988

This study was measured the radiation-induced current - X-ray dose, dose rate, X-ray quality, time, temperature, electric field characteristics and the dependence of gap length in insulating oil under of D.C. Voltage before, during and after X-ray irradiation. The obtained results can be summarized as following. 1. The radiation - induced current is more the dependence of X-ray quality (tube voltage) than quantity (tube current), the dependence of quantity is appeared at the high than low X-.ay tube voltage. 2. The dependence of dose rate is appeared at the more dose rate, and ${\triangle}\;=\;0.64{\sim}0.74$. 3. The higher temperature of insulating oil and X-ray tube voltage (X-ray quality) is increased, at the low electric field, the more radiation-induced current. 4. $G_{eq}-G_{o}(={\triangle}G)$ is increased at the low than high temperature, high than low X-ray quality. 5. The dependence of temperature is appeared before than during X-ray irradiation. 6. The RIC saturation region is appeared at the high than low insulating oil temperature during (1000 V/cm above) than before (4000 V/cm above) X-ray irradiation.

• Journal of Life Science
• /
• v.12 no.4
• /
• pp.423-426
• /
• 2002

Enantioselective resolution of racemic para-nitrostyrene oxide was investigated using epoxide hydrolase activity of Aspergillus niger LK for the production of optically pure (S)-para-nitrostyrene oxide. To overcome the poor solubility of the substrate, enantioselective hydrolysis in an organic solvent was attempted under optimized reaction conditions including reaction temperature and water content. (S)-para-Nitrostyrene oxide with high optical purity (> 99% ee) was obtained at 37% yield using fungal epoxide hydrolase-catalyzed enantioselective resolution.

• Journal of Hydrogen and New Energy
• /
• v.2 no.1
• /
• pp.15-21
• /
• 1990

Nickel-hydrogen battery systems with metal hydride alloys are expected to have both higher energy density and lower pollution than nickel-cadmium cells. Nickel-hydrogen storage cells are expected to be well-suited for use in space crafts for a large capacity power storage system. Their major advantages are not only a capability of deep DOD(depth of discharge) using but also with excellent durability under excessive overcharging and overdischarging. In this study, the charge/discharge capacities, anodic polarization characteristics and durability for the continious charge/diacharge cycling of the $Ti_{1-X}Zr_XVNi$ and $Ti_{1-X}Zr_XV_{0.5}Ni_{1.5}$ alloys were measured by electrochemical method. The electrode properties of the copper or nickel plated $Ti_{1-X}Zr_XV_{0.5}Ni_{1.5}$ alloys were examined with a battery charge/discharge testing system in the temperature range of -5 to $25^{\circ}C$.

• Toxicological Research
• /
• v.29 no.3
• /
• pp.203-209
• /
• 2013

A simple and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of ${\varepsilon}$-acetamidocaproic acid (AACA), the primary metabolite of zinc acexamate (ZAC), in rat plasma by using normetanephrine as an internal standard. Sample preparation involved protein precipitation using methanol. Separation was achieved on a Gemini-NX $C_{18}$ column ($150mm{\times}2.0mm$, i.d., 3 ${\mu}m$ particle size) using a mixture of 0.1% formic acid-water : acetonitrile (80 : 20, v/v) as the mobile phase at a flow rate of 200 ${\mu}l/min$. Quantification was performed on a triple quadrupole mass spectrometer employing electrospray ionization and operating in multiple reaction monitoring (MRM) and positive ion mode. The total chromatographic run time was 4.0 min, and the calibration curves of AACA were linear over the concentration range of 20~5000 ng/ml in rat plasma. The coefficient of variation and relative error at four QC levels were ranged from 1.0% to 5.8% and from -8.4% to 6.6%, respectively. The present method was successfully applied for estimating the pharmacokinetic parameters of AACA following intravenous or oral administration of ZAC to rats.

• Korean Journal of Pharmacognosy
• /
• v.37 no.4 s.147
• /
• pp.241-245
• /
• 2006

Morinda officinalis How. (Rubiaceae) has been used as tonic, warming, sex impulse and anti-inflammatory agents. Two known anthraquinones, rubiadin-1-methyl ether (I) and rubiadin (II) were isolated from root of M. officinalis. Their structures were identified using NMR and literature comparisons. The contents of I in eighteen M. officinalis were evaluated by HPLC-PDA. Chromatography was performed using a reversed-phase system with Luna $C_{18}$ (2) column and acetonitrile-water (50:50, v/v) with a flow rate of 1.0 mL/min under UV 280 nm. Under these conditions, the content of rubiadin-1-methyl ether was 0.013%.

• Proceedings of the KIEE Conference
• /
• 2003.10a
• /
• pp.72-74
• /
• 2003

Rf magnetron sputtering을 이용하여 InP, GaAs 기판위에 ZnO 박막을 증착시켰다. 진공 ampul 및 $Zn_3P_2$ 분위기 하에서 열처리 과정을 통해 P와 As을 ZnO 박막내에 도핑하였으며, 박막의 전기적 특성 측정 결과 정공의 농도가 $10^{16}cm^{-3}-10^{19}cm^{-3}$ 으로서 p-형 전기전도도를 나타내었다. XRD 측정을 통하여 ZnO 박막의 내부에 이상이 존재하지 않는다는 것을 확인하였다. 또한 FESEM을 이용하여 p-형 ZnO 박막의 표면을 관찰하였으며 그 위에 n-형 ZnO 박막을 sputtering을 이용하여 증착시켜 I-V 특성을 관찰하였다. 본 실험을 통해 P 및 As의 확산을 통한 p-형 ZnO 박막의 성장이 가능하였으며, I-V 특성으로부터 ZnO의 발광소자 및 자외선 검출기로의 응용이 가능함을 확인하였다.

• The Korean Journal of Pharmacology
• /
• v.12 no.2 s.20
• /
• pp.1-6
• /
• 1976

The effects of phenoxybenzamine and other related drugs were studied for their interaction with caerulein on gallbladder contraction in anesthetized animals and isolated gallbladder strips. Cholecystostomy and cystic duct ligation were made on anesthetized dog, cat and pig. Pressure changes of gallbladder were measured by a physiological pressure transducer connected to polygraph recorder. Isolated rabbit gallbladder strips were placed in a muscle chamber containing Locke-Ringer solution maintained at $38^{\circ}C$. The contractile responses were measured by a force-displacement transducer connected to polygraph recorder. Caerulein ($30{\sim}200$ ng/kg i.v.) produced marked contraction of gallbladder in situ and the cholecystokinetic potencies appear in decreasing order; dog, cat and pig. The response of caerulein was abolished by the large doses of phenoxybenzamine (15 mg/kg i.v.) but not affected with dibenamine, phentolamine or tolazoline. Cholecystokinetic effect of methacholine or barium chloride was also partially inhibited by phenoxybenzamine and the effect of caerulein was weakly inhibited intravenous injection of cyclophosphamide or papaverine. In isolated rabbit gallbladder strips, the response of contraction to caerulein were progressively inhibited by pretreatment of phenoxybenzamine along with time exposed. These results lead to the conclusion that phenoxytenzamine may inherently inhibit the contractile response of gallbladder to caerulein, and this effect was not related with ${\alpha}-adrenergic$ receptor blocking action.

• Journal of Fashion Business
• /
• v.22 no.4
• /
• pp.106-117
• /
• 2018

The present study was conducted to investigate dyeing properties and functionality of silk fabrics dyed with extracts from buckwheat skin. Comparative results of color strength(K/S) values of dyed silk fabrics were studied to quantify the effects of dye concentrations, dyeing temperatures, dyeing time and the pH; the effect of mordants; and color changes. And also evaluated the fastness, antimicrobial property, ultraviolet protection properties of the dyed and mordanted silk fabrics. The color strength(K/S) values of silk generally increased depending on the increasing dye concentration, dyeing temperature, and dyeing time. And the highest color strength values were obtained at a dye concentration of 100%(v/v), a dyeing temperature of $90^{\circ}C$, a dyeing of time 80 minutes, and a dyebath of pH 2. The color fastness to light of dyed and mordanted silk fabrics were found to be good, and the drycleaning and rubbing fastness were excellent. The fade of washing fastness was not good, however, the stain of washing fastness and perspiration fastness showed relatively good grade. The Al, Cu, Fe mordanted silk fabrics(except Fe for Klebsiella pneumoniae) showed 99.9% reduction rate. The ultraviolet protection properties of the mordanted fabrics were generally improved. Moreover, the Cu and Fe mordnared fabrics showed very exceptional ultraviolet protection factors.

• Journal of Computing Science and Engineering
• /
• v.8 no.3
• /
• pp.129-136
• /
• 2014

This paper presents the equivalent circuit modelling and eigenfrequency analysis of a wideband robust capacitive radio frequency (RF) microelectromechanical system (MEMS) switch that was designed using Poly-Si and Au layer membrane for highly reliable switching operation. The circuit characterization includes the extraction of resistance, inductance, on and off state capacitance, and Q-factor. The first six eigenfrequencies are analyzed using a finite element modeler, and the equivalent modes are demonstrated. The switch is optimized for millimeter wave frequencies, which indicate excellent RF performance with isolation of more than 55 dB and a low insertion loss of 0.1 dB in the V-band. The designed switch actuates at 13.2 V. The R, L, C and Q-factor are simulated using Y-matrix data over a frequency sweep of 20-100 GHz. The proposed switch has various applications in satellite communication networks and can also be used for devices that will incorporate the upcoming IEEE Wi-Fi 802.11ad protocol.