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컨버터로 제어되는 유도전동기 드라이브 시스템의 손실 모델링
정동화,이정철,박기태,이홍균 순천대학교 1999 순천대학교 자연과학논문집 Vol.18 No.2
An accurate loss model of induction motor drive controlled by the converter is proposed. Steady state fundamental and hamonics loss characteristics, besides the dynamics of the machine are analyzed and incorporated in the model, resulting in a new synchronous frame dynamics d-q equivalent circuit. The converter system has been modeled accurately for condition and switching losses.
정동화,이정철,박기태,이홍균 순천대학교 1999 순천대학교 자연과학논문집 Vol.18 No.2
Efficiency optimization of an indirect vector controlled induction motor drive is proposed. The loss models are used in the validation of the fuzzy logic based on-line efficiency optimization control. At steady state, the fuzzy controller adaptively changes the excitation current on the basis of measured input power, until the maximum efficiency point is reached. The pulsating torque, due to flux reduction, has been compensated by an ingenious feedforward scheme. During transient state, rated flux is established, to get the best transient response. Through a comprehensive simulation study, the results confirmed the validity of the proposed method.
적응관측기를 이용한 SPMSM의 속도 및 위치 센서리스 제어
정택기,이정철,이홍균,정동화 국립7개대학공동논문집간행위원회 2003 공업기술연구 Vol.3 No.-
This paper is proposed to position and speed control of a surface permanent magnet synchronous motor(SPMSM) drive without mechanical sensor. An adaptive state observer is used for the mechanical state estimation of the motor. The observer is developed based on a nonlinear model of the SPMSM, that employs a d-q rotating reference frame attached to the rotor. A adaptive observer is implemented to compute the speed and position feedback signal. The validity of the proposed sensorless scheme is confirmed by various response characteristics.
인슐린 비의존형 당뇨병 환자에서 24시간 혈압 변동 및 요중 알부민 배설량에 관한 연구
주기산,안기완,정종훈,배학연,홍순표 조선대학교 1995 The Medical Journal of Chosun University Vol.20 No.1
Recently, blood pressure(BP) starts to increase in close relationship to development of persistent microalbuminuria in diabetes. Thus, author studied 24-hour BP changes in diabetics compared to the those in nondiabetics and the changes of urinary albumin excretion (UAE) according to 24-hour BP changes in diabetics with microalbuminuria. Twenty-four-hour ambulatory blood pressure monitoring(ABPPM) was performed in 38 NIDDM patients(18 normotensives and 20 hypertensives) and in 37 control subjects without diabetes(18 normotensives and 19 hypertensives) . Also 24-hour ABPM was performed in 38 diabetics (20 microalbuminurit and 18 normoalbuminuric). The analysis of individual recordings allowed us to detect an impaired circadian pattern(the disappearance of the nocturnal BP decrease or a paradoxical BP increase) in 30% of the normotensive and 31% of the hypertensive diabetics. Twenty-four-hour ABPM(night systolic/diastolic ±SD mmHg) was significantly higher in microabluminuric(124.2 ±11.4/75.1±8.2 mmHg) than in normoalbuminuric subject, (114.0±7.6/64.6±6.6 mmHg, p<0.05). This study suggests that not only awaking BP but also especially day-night minimum SBP decrease are highly responsible for the renal impairment in NIDDM patients, unrelation to hypertension. Thus. ABPM reflects the association between UAE and blood pressure in diabetics more precisely than clinical measurements. and a significant correlation exists between rate of increase in Urinary albumin excretion and blood pressure in diabetics.
Fluoxetine이 Schedule-Induced Polydipsia가 유발된 백서 뇌에서 Tyrosine Hydroxylase 발현에 미치는 영향
이기철,이정호,최영민,정주호,정홍경,이용민,김도형,이대환 大韓神經精神醫學會 2001 신경정신의학 Vol.40 No.2
연구목적: Fluoxetine은 serotonin을 매개하여 간접적으로 dopamine 신경전달기능을 억제한다고 추정되고 있다. 또한 운동장애에서 운동기능의 악화를 유발한다고 알려져 있다. 그러나 신경세포체에서 fluoxetine이 dopamine에 어떠한 영향을 주는지는 아직까지 확실치 않다. 저자들은 schedule-induced polydipsia를 유발시킨 백서 뇌의 흑질, 복부피개영역, 미상핵에서 tyrosine hydroxylase(TH) 발현이 저하됨을 발견하였다. 이를 통해서 fluoxetine이 백서 뇌의 dopamine 기능에 긍정적인지 혹은 부정적인지를 규명하고자 하였다. 방법: 4주간의 schedule-induced polydipsia 과정을 거친 백서에서 면역죄치화학적인 방법으로 흑질, 복부피개영역, 미상핵의 tyrosine hydroxylase 발현이 저하됨을 확인한 후, 실험동물들에게 fluoxetine 10mg/kg를 3주간 복강내 주사하였다. 실험백서들을 희생시켜 뇌 조직을 적출하여, TH 면역조직화학 염색법을 이용하여 흑질, 복부피개영역, 그리고 미상핵의 TH 면역반응세포를 관찰하고 이를 정상백서와 비교하였다. 결과: 1) 다갈증이 유발된 백서의 흑질, 복부피개영역, 미상핵에서 tyrosine hydroxylase 발현이 정상백서 보다 저하됨을 관찰하였다. 2) 3주간에 걸친 fluoxetine 투여후 흑질, 복부피개영역, 미상핵의 tyrosin hydroxylase 발현이 다시 증가하는 소견을 보였다. 결론: Fluoxetine 만성투여가 흑질, 복부피개영역 그리고 미상핵의 tyrosin hydroxylase를 증가시키는 소견을 얻었다. 이러한 결과는 임상에서 dopamine 결핍과 연관된 질환들에서 fluoxetine을 만성투여하면 운동기능을 포함한 증상들의 개선을 가져올 수도 있다고 추정된다. Objective: It has been suggested that fluoxetine inhibits the dopaminergic neurotransmission by serotonergic mediation. And also, it has been shown to inhibit synthesis of DOPA in dopamine-rich areas of the rat forebrain. These dopamine-antagonistic capacity of fluoxetine is only supported by anecdotal report that the increased amount of motor disability in patients with idiopathic Parkinson's disease after exposure to fluoxetine. However, there is still no evidence of the direct effect of fluoxetine on dopaminergic neuronal cell body in the substantia nigra, VTA, caudate & putamen. This study was designed to evaluate the effects of fluoxetine in rat brain which showed decreased numbers of dopaminergic neuronal cell body induced by schedule-induced polydipsia(SIP). Method: We incidentally found that 4 weeks of schedule-induced polydipsic rats revealed the suppression of tyrosine hydroxylase expression in the substantia nigra, VTA, caudate & putamen with the immunohistochemistric measures. After 3 weeks of intraperitoneal injection of 10mg/kg of fluoxetine to the schedule induced polydipsic rats, the tyrosine hydroxylase expression was also measured with immunohistochemistry. We compared the tyrosine hydroxylase expression among the normal control, the polydipsic rats, and the rats with fluoxetine treatment. Results: 1) By contrast with the control, the polydipsic rats revealed the evidence of decreased tyrosine hydroxylase expression in the substantia nigra, VTA, caudate & putamen. 2)After daily injection of fluoxetine for 3 weeks, the polydipsic rats showed increment of tyrosine hydroxyase expression in those areas. Conclusions: In previous studies, a great deal of results suggest that fluoxetine negatively influence the dopaminergic systems indirectly via serotonergic activation such as inhibition of dopamine synthesis or transport system. Although our results are obtained from rodents, we suggest that fluoxetine directly and positively enhance the dopamine system in the substantia nigra, VTA, caudate & putamen. The chronic adminstration of fluoxetine may be helpful to dopamine-depleted condition in clinical situations. We anticipate the replication studies of our findings and well-controlled clinical trial.
우리나라 하수 및 폐수 처리 슬러지의 다환방향족탄화수소의 함량 : (2) Non-alkylated Polycyclic Aromatic Hydrocarbons
이강영,정창수,김영일,이현경,홍기훈 한국환경과학회 2005 한국환경과학회지 Vol.14 No.4
The 16 priority PAHs (Polycyclic Aromatic Hydrocarbons) designated by US Environmental Protection Agency were analyzed for some digested sludges from wastewater treatment plants in Korea. PAHs are an important group of organic contaminants present in sewage sludge due to their persistence and toxic potential. PAHs were extracted from freeze-dried sludges using a methylene chloride-methanol (2:1) mixture in a soxhlet extractor. The extracts were cleaned-up by silica gel/alumina combination column and subsequently fed into gas chromatograph/mass spectrometer (GC/MS) for determining PAH contents. The sum of the 16 PAHs in the sewage sludge varied from 534.8 to 5754.5 μg/kg, dry wt.. In the sewage sludge, phenanthrene appears as the most abundant PAHs, followed by naphthalene, pyrene, fluoranthene. Source of the investigated sewage sludges relatively predominated pyrogenic. PAHs levels of sewage sludges in Korea appeared to be lower than those in other countries.