• 조명전기설비학회논문지
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• 제21권5호
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• pp.10-24
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• 2007

본 연구에서는 연료전지의 전압을 $380[V_{DC}]$로 승압하기 위한 새로운 절연형 DC-DC 컨버터와 단상 $220[V_{DC}]$로 변환하기 위한 LC필터를 가진 PWM 인버터로 구성된 연료전지용 전력변환장치를 제안하였다. 여기서 기존의 컨버터보다 부품수가 적고 제어가 용이하며, 대용량에 적합한 새로운 DC-DC 컨버터는 2차측에 스위치 $S_5,\;S_6$을 추가로 구성하여 위상천이 폭을 조절함으로써 출력 전력을 제어할 수 있으며, 넓은 출력 전압 조정에서도 $93{\sim}97[%]$의 효율을 얻을 수 있다. 그리고 연료전지와 유사한 출력 특성을 갖는 연료전지 시뮬레이터를 구현하였으며, 적절한 데드 타임 td을 제어하여 고주파 변압기의 여자 전류의 피크값과 고주파 변압기 1차측 전류가 일치하는 부분에서 소프트 스위칭을 실현 시켰다. 또한 직렬 인덕턴스 La를 추가적으로 적절하게 설정하여 2차측의 스위치와 직렬 다이오드에 발생하는 서지 전압과 경부하시에 발생되는 도통 손실을 저감시켰다. 끝으로 TMS320C31보드와 EPLD를 이용한 PWM 스위칭 기법에 의해 동작하는 단상 인버터를 설계, 제작하여 가정용 교류전압 공급에 유용하게 활용할 수 있다.

• 농약과학회지
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• 제18권1호
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• pp.1-7
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• 2014

본 연구는 참외에 대한 살균제 metalaxyl-M과 flusilazole의 잔류량 변화를 측정하여 약제별 잔류특성을 파악하고, 반감기를 산출함으로써 생산단계 잔류허용기준(PHRL, Pre-Harvest Residue Limit) 설정을 위한 기초자료로서 활용하고자 수행하였다. 공시 약제인 metalaxyl-M과 flusilazole은 안전사용기준에 준하여 7일 간격으로 1회, 2회살포하였으며, 살포 2시간 후를 0일차로 하여 0, 1, 2, 3, 5, 7, 9, 11일차에 수확하였고, 잔류량의 경시변화 결과를 토대로 생물학적 반감기를 산출하였다. 시료는 QuEChERS방법을 이용하여 전처리하였으며, metalaxyl-M의 경우 GC/NPD를 이용하여 분석하였으며, flusilazole은 LC/MS/MS를 이용하여 분석하였다. 참외 중 metalaxyl-M과 flusilazole의 LOQ (Limit of quantitation)는 각각 0.02 mg/kg, 0.01 mg/kg이었으며, metalaxyl-M 회수율은 95.7-103.2%이었고, flusilazole은 100.2-106.8%이었으며, 표준편차는 모두 10% 미만이었다. 참외 중 각 농약에 대한 생물학적 반감기는 flusilazole의 경우 1, 2회 처리구에서 12일이었으며, metalaxyl-M의 경우 23일이었다. 본 연구결과, metalaxyl-M 및 flusilazole의 수확 10일 전 PHRL은 각각 1.5, 0.3 mg/kg로 나타났으며, 수확 시 metalaxyl-M, flusilazole의 잔류농도는 MRL을 초과하지 않을 것으로 예측되었다.

• 농약과학회지
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• 제17권2호
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• pp.84-93
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• 2013

Isopyrazam은 신규 농약으로 현재 국내에는 공정분석법이 확립되어 있지 않아 농산물 중 잔류농약 분석을 위한 개별 분석법 개발이 필요하다. 본 연구는 현미, 대두, 고추, 감귤, 참외, 오이를 대표 농산물로 선정하여 isopyrazam에 대한 공정 개별 분석법을 확립하고자 수행되었다. Isopyrazam의 syn과 anti 이성질체를 분석하기 위해 여러 가지 추출, 분배 및 정제방법을 비교하면서 최적의 조건을 충족해 가며 분석법을 확립하였다. 대표 농산물 시료 중 함유된 isopyrazam은 acetonitrile로 추출한 후 n-hexane으로 액-액 분배하였으며, florisil을 이용하여 정제한 후 HPLC/UVD로 최종 분석하였다. 시료 중 현미와 대두는 n-hexane/acetonitrile을 이용한 유지제거 과정을 추가하였다. 본 분석법의 isopyrazam에 대한 정량한계는 1.0 ng (S/N > 10)이었고, 분석정량한계는 0.04 mg $kg^{-1}$이었다. 회수율은 isopyrazam syn과 anti-isomer에서 각각 81.0~105.4%, 80.8~105.6%이었으며, 반복 간 분석오차는 10% 미만이었다. 분석성분에 대한 확인을 위하여 LC/MS SIM을 이용하였다. 본 연구에서 확립된 isopyrazam의 분석법은 우수한 정량성 및 재현성, 분석과정의 편의성을 고려할 때 농산물 중 잔류농약에 대한 검사 및 안전성 평가를 위한 공정 분석법으로 활용될 수 있을 것으로 사료된다.

• The Korean Journal of Physiology and Pharmacology
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• 제7권5호
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• pp.267-273
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• 2003

We have investigated the effect on inducing substate(s) of positively charged residues replaced in position 172 of the second transmembrane domain in murine inward rectifier potassium channels, formed by stable or transient transfection of Kir2.1 gene in MEL or CHO cells. Single channel recordings were obtained from either cell-attached patches or inside-out patches excised into solution containing 10 mM EDTA to rule out the effect of $Mg^{2+}$ on the channel gating. The substate(s) could be recorded with all mutants D172H, D172K and D172R. The unitary current-voltage (I-V) relation was not linear with D172H at $pH_i$ 6.3, whereas the unitary I-V relation was linear at $pH_i$ 8.0. The relative occupancy at $S_{LC}$ was increased from 0.018 at $pH_i$ 8.0 to 0.45 at $pH_i$ 5.5. In H-N dimer, that was increased from 0.016 at $pH_i$ 8.0 to 0.23 at $pH_i$ 5.5. The larger the size of the side chain or $pK_a$ with mutants (D172H, D172K and D172R), the more frequent the transitions between the fully open state and substate within an opening. The conductance of the substate also depended upon the pKa or the size of the side chain. The relative occupancy at substate $S_{LC}$ with monomer D172K (0.50) was less than that in K-H dimer (0.83). However, the relative occupancy at substate with D172R (0.79) was similar to that with R-N dimer (0.82). In the contrary to ROMK1, positive charge as well as negative charge in position 172 can induce the substate rather than block the pore in murine Kir2.1. The single channel properties of the mutant, that is, unitary I-V relation, the voltage dependence of the mean open time and relative occupancy of the substates and the increased latency to the first opening, explain the intrinsic gating observed in whole cell recordings.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2011년도 추계학술대회
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• pp.423-424
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• 2011

본 논문은 IEEE 802.15.4g SUN (Smart utility network)을 지원하는 920 MHz 대역 RF 송수신단 통합회로 구조를 제안한다. 제안하는 통합회로는 920 MHz에서 동작하고 구동증폭기, RF 스위치, 그리고 저잡음 증폭기로 구성되어 있다. 송신모드에서는 구동 증폭기가 동작하는데 싱글 구조로 설계되어 트랜스퍼머에 의한 출력 신호 손실을 제거 하였고 또한 RF 스위치의 위치를 수신단에 적용하여 출력 신호 손실을 제거 하였다. 수신모드에서는 RF 스위치와 저잡음 증폭기가 동작되는데 싱글 입력 신호에 대해 차동 출력 신호를 제공할 수 있다. 구동증폭기의 부하와 저잡음 증폭기의 입력 정합회로는 한 개의 LC 공진회로를 공유하여 칩 면적을 최소화 할 수 있다. 본 논문에서 제안하는 통합회로는 $0.18-{\mu}m$ CMOS 공정을 사용하여 설계하였고, 1.8 V 공급 전압에서 구동증폭기는 3.6 mA, 저잡음 증폭기는 3.1 mA의 전류를 소모한다.

• 한국환경보건학회지
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• 제23권2호
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• pp.64-71
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• 1997

This study was performed to investigate the effect of co-existence of carbofuran and chlorothalonil on the short-term bioconcentration factor in Brachydanio rerio(zebrafish). The fishes were exposed to the single and combined treatment of carbofuran and chlorothalonil for 1, 3 and 5 days. Experimental concentrations of carbofuran were 0.05 and 0.10 ppm under the single treatment. And those of chlorothalonil were 0.005 and 0.010 ppm. Experimental concentrations of the combined treatment of carbofuran and chlorothalonil were 0.05 ppm+0.005 ppm, 0.05 ppm+0.010 ppm, 0.10 ppm+0.005 ppm for 1, 3 and 5 days, respectively. Carbofuran and chlorothalonil in fish and in test water were extracted with n-hexane and acetonitrile. GC-ECD was used to detect and quantitate carbofuran and chlorothalonil. 1-day, 3-day and 5-day bioconcentration factors(BCF$_1$, BCF$_3$ and BCF$_5$) of each pesticide were obtained from the quantitation results. The depuration rate of each pesticide was determined over the 24-h period after combined treatment. The results were as follows: Carbofuran did not bioaccumulate in zebrafish under the single and combined treatment for testing periods. BCF$_1$ values of chlorothalonil in concentration of 0.005 and 0.010 ppm under the single treatment were 0.508, 0.621, BCF$_3$ were 1.327, 1.511 and BCF$_5$ were 1.331, 1.597, respectively. BCF$_1$ values of chlorothalonil were 0.512, 0.520 and 0.619, respectively, when the concentration of carbofuran and chlorothalonil in combined treatment were 0.05+0.005, 0.05+0.010 and 0.10+0.005 ppm. BCF$_3$ values of chlorothalonil 1.341, 1.338 and 1.513, respectively, and BCF$_5$ values of chlorothalonil were 1.332, 1.327 and 1.521, respectively, under the above combined treatment. Depuration rate constants of chlorothalonil in concentration of 0.005 and 0.010 ppm under the single treatment were 0.011 and 0.012. Depuration rate constants of chlorothalonil were 0.011, 0.010 and 0.011, when the concentration of carbofuran and chlorothalonil in combined treatment were 0.05+0.005, 0.05+0.010 and 0.10+0.005 ppm. It was observed that no significant difference of carbofuran and chlorothalonil concentration in fish extracts, test water, BCFs and depuration rate constants of carbofuran and chlorothalonil between combined treatment and single treatment. It was considered that no appreciable interaction at experimental concentrations due to lower concentrations than LC$_{50}$. It is suggested that the difference of BCFs between carbofuran and chlorothalonil due to those of fat composition of fish and solubility of carbofuran and chlorothaionil.

• 대한예방한의학회지
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• 제21권2호
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• pp.127-137
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• 2017

Objectives : In our previous study, single co-administration GMODT within 5 min significantly inhibited the oral bioavailability of tamoxifen through variable influences on the absorption and excretion of tamoxifen. Therefore, the object of this study was to elucidate the possible effects on the pharmacokinetics of tamoxifen after single oral co-administration of GMODT with 2.5 hr-intervals. Methods : After 50 mg/kg of tamoxifen treatment, GMODT 100 mg/kg was administered with 2.5 hr-intervals. The plasma were collected at 30 min before administration, 30 min, 1, 2, 3, 4, 6, 8 and 24 hrs after end of GMODT treatment, and plasma concentrations of tamoxifen were analyzed using LC-MS/MS methods. PK parameters of tamoxifen (Tmax, Cmax, AUC, $t_{1/2}$ and $MRT_{inf}$) were analysis as compared with tamoxifen single administered rats. Results : Two-half hr-interval co-administration with GMODT induced variable changes on the plasma tamoxifen concentrations as compared with tamoxifen single treated rats, and especially significant (p<0.05) increases of plasma tamoxifen concentrations were demonstrated at 0.5 (199.61%) and 1 hr (101.06%) after end of co-administration with GMODT, and also related significant (p<0.05) decreases of $t_{1/2}$ (-39.54%) and $MRT_{inf}$ (-43.94%) as compared with tamoxifen single formula treated rats, at dosage levels of tamoxifen 50 mg/kg and GMODT 100 mg/kg with 2.5 hr-intervals, in this experiment. Conclusions : According to the results, GMODT critically decreased on the oral bioavailability of tamoxifen through variable influences on the absorption and excretion of tamoxifen. Hence, the co-administration of GMODT and tamoxifen should be avoided in the comprehensive and integrative medicine, combination therapy of tamoxifen with GMODT on the breast cancer.

• 대한예방한의학회지
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• 제19권1호
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• pp.145-159
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• 2015

Objective : In the previous study, co-administration of Gongjindan-gamibang (GJD) with sorafenib increased oral bioavailability of sorafenib through augment the absorption, therefore, the effects of GJD co-administration on the pharmacokinetics of sorafenib were observed after single and 7-day repeated oral co-administration with 3.5 hr-intervals in the present study. Method : After 50 mg/kg of sorafenib treatment, GJD 100 mg/kg was administered with 3.5 hr-intervals. The plasma were collected at 30 min before administration, 30 min, 1, 2, 3, 4, 6, 8 and 24 hrs after end of first and last 7th sorafenib treatment, and plasma concentrations of sorafenib were analyzed using LC-MS/MS methods. PK parameters of sorafenib ($T_{max}$, $C_{max}$, AUC, $t_{1/2}$ and $MRT_{inf}$) were analysis as compared with sorafenib single administered rats. Results : GJD markedly inhibited the absorption of sorafenib, from 1 hr to 24 hrs after end of first 3.5 hr-interval co-administration, the $C_{max}$ (-43.27%), $AUC_{0-t}$ (-56.29%) and $AUC_{0-inf}$ (-66.70%) of sorafenib in co-administered rats were dramatically decreased as compared with sorafenib single treated rats. However, GJD significantly increased the absorption of sorafenib, from 4 hr to 8 hrs after end of last 7th 3.5 hr-interval co-administration, the $AUC_{0-t}$ (34.08%) and $AUC_{0-inf}$ (37.31%) of sorafenib in co-administered rats were dramatically increased as compared with sorafenib single treated rats. Conclusion : Although GJD decreased the oral bioavailability of sorafenib through inhibition of gastrointestinal absorptions after end of first 3.5 hr-interval co-administration, it is observed that GJD increases the oral bioavailability of sorafenib as facilitated the absorption after end of last 7th repeated co-administration. Hence, the co-administration of GJD and sorafenib should be avoided in the combination therapy of sorafenib with GJD on anticancer therapy.

• 대한예방한의학회지
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• 제17권2호
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• pp.139-155
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• 2013

Purpose : This study was aim to evaluate effects of pharmacodynamics and toxicity in combination therapy of donepezil with Gongjindan. The effects of Gongjindan co-administration on the pharmacokinetics (PK) of donepezil were observed after single and 7-day repeated oral co-administration with 1.5hr-intervals, to evaluate synergic pharmacodynamics and reduce toxicity of combination therapy of donepezil with Gongjindan. Materials and Methods : After 10mg/kg of donepezil treatment, Gongjindan100mg/kg was administered with 1.5hr-intervals. The plasma were collected at 30min before administration, 30min, 1, 2, 3, 4, 6, 8 and 24hrs after end of first and last 7th donepezil treatment, and plasma concentrations of donepezil were analyzed using LC-MS/MS methods. Results : Gongjindan markedly inhibited the absorption of donepezilregardless of sample time, from 30min to 8hrs after end of first 1.5hr-interval co-administration as compared with donepezil single treated rats. Especially the absorption of donepezil was significantly decreased at 2, 4, 6 and 8hrs after co-administration as compared with donepezilsingle treated rats. Accordingly, the Cmax (-26.236%), $AUC_{0-t}$(-26.02%) and $AUC_{0-inf}$(-25.90%) of donepezil in 1.5hr-interval co-administered rats were dramatically decreased as compared with donepezilsingle treated rats, respectively. However, no meaningful changes on the plasma donepezil concentrations and pharmacokinetic parameters were detected after end of last 7th 1.5hr-interval co-administration as compared with donerezil single treated rats, except for non-significant slight increases of Tmax(16.67%) detected in co-administered rats as compared with donepezil single treated rats. Conclusion : These findings are considered as direct evidences that Gongjindan also decreased oral bioavailability of donerezil as inhibited the absorptions, when they were co-administered with 1.5hr-intervals, but they may be adapted after 7 days continuous repeated l.5hr-interval co-administration.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.484-488
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• 2001

The grid voltage of commercial utility power source hi Japan and USA is 100rms, but in China and European countries, it is 200rms. In recent years, In Japan 200Vrms out putted single phase three wire system begins to be used for high power applications. In 100Vrms utility AC power applications and systems, an active voltage clamped quasi-resonant Inverter circuit topology using IGBTs has been effectively used so far for the consumer microwave oven. In this paper, presented is a half bridge type voltage-clamped high-frequency Inverter type AC-DC converter using which is designed for consumer magnetron drive used as the consumer microwave oven in 200V utility AC power system. This zero voltage soft switching Inverter can use the same power rated switching semiconductor devices and three-winding high frequency transformer as those of the active voltage clamped quasi-resonant Inverter using the IGBTs that has already been used for 100V utility AC power source. The operating performances of the voltage source single ended push pull type Inverter are evaluated and discussed for consumer microwave oven. The harmonic line current components In the utility AC power side of the AC-DC power converter operating at ZVS­PWM strategy reduced and improved on the basis of sine wave like pulse frequency modulation and sine wave like pulse width modulation for the utility AC voltage source.