• 대한수의학회지
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• 제60권4호
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• pp.209-213
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• 2020

This study examined the residue of dl-methylephedrine hydrochloride (MEP) on the muscle of pigs administered orally with MEP 12 g/ton feed for seven consecutive days. Twenty healthy cross swine were administered MEP. Four treated animals were selected arbitrarily to be sacrificed at 1, 2, 3, 4, and 5 days after treatment. MEP residue concentrations in the muscle were determined by liquid chromatography coupled with tandem mass spectrometry. The drug was extracted from muscle samples using 10 mM ammonium formate in acetonitrile followed by clean-up with n-hexane. The analyte was separated on an XBridgeTM hydrophilic interaction liquid chromatography column using 10 mM ammonium formate in deionized distilled water and acetonitrile. The correlation coefficient (R2) of the calibration curve was 0.9974, and the limits of detection and quantification were 0.05 and 0.15 ㎍/kg, respectively. The recoveries at three spiking levels were 94.5-101.2%, and the relative Standard Deviations was less than 4.06%. In the MEP-treated group, MEP residues on one day post-treatment were below the maximum residue limit in the muscle. The developed method is sensitive and reliable for the detection of MEP in porcine muscle tissues. Furthermore, it exhibits low quantification limits for animal-derived food products destined for human consumption.

• JSTS:Journal of Semiconductor Technology and Science
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• 제9권4호
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• pp.192-197
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• 2009

This paper presents the design and measurement of a 2.4/5.2-GHz dual band VCO with a balanced frequency doubler in $0.18\;{\mu}m$ CMOS process. The topology of a 2.4 GHz VCO is a cross-coupled VCO with a LC tank and the frequency of the VCO is doubled by a frequency balanced doubler for a 5.2 GHz VCO. The gate bias matching network for class B operation in the balanced doubler is adopted to obtain as much power at 2nd harmonic output as possible. The average output powers of the 2.4 GHz and 5.2 GHz VCOs are -12 dBm and -13 dBm, respectively, the doubled VCO has fundamental harmonic suppression of -25 dB. The measured phase noises at 5 MHz frequency offset are -123 dBc /Hz from 2.6 GHz and -118 dBc /Hz from 5.1 GHz. The total size of the dual band VCO is $1.0\;mm{\times}0.9\;mm$ including pads.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1399-1400
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• 2008

본 논문에서는 TSMC 0.18um 공정을 이용하여 2.45GHz 대역에서 동작하는 RFID 리더에 적용 할 수 있는 전압제어 발진기를 설계하였다. 위상 잡음 특성 향상을 위해 PMOS, NMOS 소자를 대칭으로 구성한 complementary cross-coupled LC 발진기 구조로 설계 하였고 MOS 배렉터를 이용하여 주파수를 가변 하였다. 또한 공정에서 사용되는 인덕터에 차폐 도체면(PGS:Patterned Ground Shield) 구조를 삽입했을 때 인덕터의 품질계수가 약 5.82% 향상되었고. 이에 따른 위상 잡음은 1MHz offset 주파수에서 PGS를 삽입하지 않는 구조에서는 -102.666dBc/Hz 이며, PGS 구조를 삽입한 구조는 -104.328dBc/Hz로 약1.662dBc 정도의 성능이 향상 되었다. 전압제어 발진기 Core 사이즈는 900um ${\times}$ 590um이고 주파수 가변 범위는 배렉터 전압 1.2${\sim}$2.1V에서 249MHz로 11.4% 특성을 보였다. 1.8V공급전압에서 5.76mW의 전력소모를 보였다.

• 분석과학
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• 제16권2호
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• pp.134-142
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• 2003

LC-ICP-MS를 이용한 어류중 비소의 종분화 분석을 위해 microwave-assisted extraction과 sonication extraction 방법을 비교하였다. Ultrasonic nebulizer와 cross flow nebulizer를 사용한 비소종들의 검출한계는 유사한 결과를 보였다. 분석된 비소 종들은 arsenobetaine (AsB), arsenite [As(III)], dimethylarsine acid (DMA), monomethylarsonic acid (MMA), arsenate [As(v)] 와 phenylarsonic acid (PAA) 이다. 두 가지 방법은 NRCC (National Research Council of Canada)의 표준물질인 DORM-2를 50% 메탄올로 추출하였다. arsenobetaine의 경우, 두 방법 모두 5% 이하의 상대표준편차와 82% 이상의 추출효율을 보였다. Arsenobetaine은 microwave assisted extraction 방법에서 $14.18{\pm}0.42mg\;kg^{-1}$을 보였고 sonication extraction 방법에서는 $13.54 {\pm}0.84mg\;kg^{-1}$을 보였다. dimethylarsine acid (DMA)의 경우 각각 $0.45{\pm}0.06mg\;kg^{-1}$과 $0.44{\pm}0.06mg\;kg^{-1}$를 보였다.

• Journal of Pharmaceutical Investigation
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• 제37권6호
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• pp.397-402
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• 2007

To evaluate the bioequivalence of two venlafaxine formulations, a standard 2-way randomized cross-over study was conducted in twenty-four healthy male Korean volunteers. A single oral dose of 75 mg of test formulation Venfaxine $OR^{(R)}$ (tablet) or reference formulation Efexor $XR^{(R)}$ (capsule) was administered with one-week washout period. Plasma concentrations of venlafaxine were assayed for over a period of 72 hours with a well validated method using liquid chromatography coupled to tandem mass spectrometry (LC-MS-MS). The $mean{\pm}S.D$. of maximum concentration $(C_{max})$ and elimination half-life $(t_{1/2})$ were $64.7{\pm}28.5$ ng/mL, $9.2{\pm}3.0$ h, and $67.2{\pm}30.2$ ng/mL, $9.9{\pm}3.5$ h for test and reference formulations, respectively. Time to reach maximum concentration $(T_{max})$ expressed in median value (range), for the test and the reference, were 10 h (6-14) and 8h (4-12), respectively. Similarly, area under the plasma concentration-time curve, from time zero to last sampling time $(AUC_t)$ and from time zero to time infinity $(AUC_{inf})$, for test and reference formulations were $1185{\pm}755$, $1326{\pm}896$ and $1124{\pm}737$, $1185{\pm}755$ $ng{\cdot}h/mL$, respectively. The parametric 90% confidence intervals on the mean of the differences between the two formulations (test-reference) of the log transformed values of $AUC_t$, and $C_{max}$ were 0.9630 to 1.1383 and 0.8650 to 1.0446, respectively. The overall results indicate that the two formulations are bioequivalent and can be prescribe interchangeably.