入力電流의 高調波 低減을 위한 새로운 다이리스터 整流回路의 개발

柳喆魯,金聖中,李公熙,李星龍,高榮浩 全北大學校 1987 論文集 Vol.29 No.-

The harmonics involved in input AC line currents of thyristor rectifier apparatus have recently been a serious problem in the cause of burning power condenser, mis-action of UFR(protective relay), and trouble of the automatic voltage controller, etc, in the sending or distribution electric power system. As an effective counter-measure for this, the method of having switching taps on the conventional interphase reactor and its artificial utilization have been adapted, as we know. The conventional 3 tap method, however, is not achieved an effect of reducing harmonics under firing angle 15˚. In this paper, a new method of reducing harmonics involved in input AC line currents or output DC voltage of rectifier circuit is presented, which is due mainly to the equipment of the 2-3 switching taps on interphase reactor. Thereofre, main contents of this study are the following three items; 1) optimal number of taps 2) optimal turn ratio of interphase reactor 3) optimal control angle of interphase reactor.

入出力 高調波 低減形 VVVF 시스템으로 制御되는 3相 誘導電動機 高效率 運轉

柳喆魯,李公熙,李星龍 全北大學校 1990 論文集 Vol.32 No.-

Recently, the variable speed control by the VVVF system for controlling induction motor has been applied in the various field. But the harmonic which is generated in rectifier and inverter device give rise to the various obstacles. And also the efficiency improvement of induction motor, which is occupied above 80% in the industrial areas, is important to economize the energy because the induction motor has fault that it is the low efficiency in the low load. Therefore, in this study 1. From the side of reducing harmonics in input-output currents a. The reduction of harmonics by the tap changing method of converter b. The reduction of harmonics by the PWM method of inverter 2. From the side of the variable and the high efficiency of induction motor drive a. The problem of lock by the novel PLL system b. The problem of design of the V/f controller 3. From problem of simplification of the system a. The problem of simplification of the system b. The problem of the main transformer capacity and turn ratio In comparison with optimum value by computer simulation about the above items, we have made this system in accordance with theory, and then proved this validity through experiments. And also we developed the high efficiency drive system of induction motor for reducing harmonics in input-output currents by applying this conclusion.

새로운 다중 전류원 인버어터의 개발

유철로,김홍규,이공희,이성룡 全北大學校 1992 論文集 Vol.34 No.-

A new multiple current source inverter for reducing the harmonics in output current is presented in this study. Condenser capacity necessary for the inverter design is decided by the commutation analysis of current source inverter with induction motor as load. And the proposed system operates 24 phase inverter by adding only tap changing circuit which consists of several taps and static switching elements to the 12 phase inverter, which is the double connected 6 phase inverter with an interphase reactor. Also to optimize the effectiveness of the harmonic reduction, the optimum turn ratio and tap changing control angle of interphase reactor are decided by digital simulation and its validity is verified with experiment. And under the optimum condition, it is clarified that the harmonics components involved in the output currents of the proposed inverter are nearly equal to those of the conventional 24 pulse inverter.

Digital PLL을 利用한 誘導電動機 速度 制御 System의 인버어터 出力 波形 改善에 關한 硏究

柳喆魯,李公熙,李星龍 全北大學校 1985 論文集 Vol.27 No.-

The inverter design for improving current waveforms using only reactors and capacitors is described. Some effects of harmonics on induction motor is reduced when the improved inverter applied to digital PLL speed control system. This paper also presented a determinating method of dynamic response and stability of system using microprocessor-based digital filter. Excellent speed regulation was obtained by the improved control system.

석탄회 및 석고첨가가 퇴비화에 미치는 영향

유현철,김정섭,곽명화,윤철종,이희인,박승조 동아대학교 환경문제연구소 2001 硏究報告 Vol.24 No.1

Problems of wastes that pigs produce are increasing rapidly in the hog raising industry nowadays. consequently, the generation volume of excreta also is increasing but most of that is not disposed appropriately and exposed in eco-system therefore the disposal of stock excreta is becoming more and more serious. considering the physical and chemical characteristics of livestock excreta, the pollution loading rate - BOD, COD etc. - is very high. as alternative plan, that is, as one method kind of composisting, the utilization of the soil reformation agent will become one solution in managing the upper problems. also, the flyash of 3.7 million tons are producing every year and about 32.2% of that, 1.18 million ton is recycled as concrete, cement, cementassistance, road etc. consequently, the discharged flyash is not abandoned and a plan of recycling is needed acutely. gypsum of 4.16 million tons in 1998 presently was produced and about 57.2% of that, 2.38 million tons was recycled as cement, construction materials. the present stock is 25 million tons. therefore, in this study, because organic materials can be obtained in pig excreta and calciums can be obtained in gypsum, the small amount of elements can be acquired in flyash for the soil reformation agents, mixing the three materials - pig excreta, gypsum, flyash - adequately, investigated technique of making the soil reformation agents and described below in comparrision with the changes of temperature, PH TOC, T-N, TOC/T-N ratio etc.

高調波 低減形 整流回路의 最適化에 관한 硏究

柳喆魯,金聖中,李公熙,李星龍 全北大學校 1989 論文集 Vol.31 No.-

The harmonics involved in input AC line currents of thyristor converter apparatus have generated such serious problems as burning of power condenser, misaction of UFR(protective relay), and trouble of the automatic voltage controller, etc., in transmission and distribution of electric power system. In this study, we have analyzed the characteristics of the converter for reducing harmonics, which originate all sorts of obstacles. And in order to maximize the effect for the reduction of harmonics, we researched into the following items. A. From the side of reducing harmonics. 1) Optimum value of turn ratio and number according to the increment of switching tap on interphase reactor. 2) Optimum value of control angle of tap changing. 3) Development of new tap changing algorithm according to control angle of main converter. B. From the side in consideration of economical efficiency 1) Determination of the uppermost limit according to increment of switching tap on interphase reactor. 2) Turn ratio and capacity of main trasformer. 3) Turn ratio and capacity of interphase reactor. In comparison with optimum value by computer simulation about the above items, we have made this converter system in accordance with theory, and then proved this validity through experiments. Therefore, we developed the converter of optimal condition which could be used practically by applying this conclusion.

靜止形 3相 無停電 電源 裝置用 電壓源 인버터의 出力 波形 改善

柳喆魯,李公熙,韓宇勇 全北大學校 1994 論文集 Vol.37 No.-

Uninterruptible power supply[UPS] systems are extensively used for electrical support of computers, communications and other critical systems. At present, most of all inverters used in UPS system are voltage source inverter[VSI]. But the output voltage of the UPS must be a sinusoidal wave, therefore a filter consisting of inductors and capacitors eliminates the harmonics involved in the output voltage of VSI. It is important for making UPS more compact to make the filter smaller. For this purpose, the multi step VSI for UPS systems is presented in this paper. The proposed system operates as like 24 and 36 step VSI by adding the tap changing auxiliary circuit which consists of an auto transformer and several switching elements to the double connected 12 step VSI. The basic theories of the proposed inverter system for analyzing the output waveforms are described. And to optimize the effectiveness of the harmonic reduction, the optimum turn ratio and tap changing control angle of auto transformer are decided by simulation and its validity is verified with experiment.

Ciprofloxacin 제제의 생물학적 동등성에 관한 연구

최철희,신재국,신완균,유호진,이경훈,정원석,장인진,신상구 대한화학요법학회 1991 대한화학요법학회지 Vol.9 No.1

국내 시판중인 ciprofloxacin 제제인 Citopcin®(250㎎ tablet)의 동등성을 검토하기 위해 제조원인 Bayer사의 Citopcin®(250㎎ tablet)를 기준제제로 하여 18명의 건강한 남성 피험자를 대상으로 500㎎ 1회 교차 경구 투여후 약동학적 성상을 분석비교한 결과는 다음과 같다. 시험제제의 생체 이용율의 지표인 AUC, C_(mao), T_(max) 및 MRT들의 평균치는 백분율차이에 있어 모든 기준제제 지표의 ± 20% 이내였으며, 이들 생체 이용율 지표들은 분산분석 검정에서 차이를 인지할 수 없었다.생체 이용율 지표들의 기준제제에 대한 백분율 90% 대칭 신뢰구간 검토시 모든 경수들에서 ± 20% 이내의 조건을 만족하였으며 AUC의 경우에는 대칭형 신뢰구간으로 변환시 95% 신뢰구간에서도 동등성의 조건을 만족하였다, 이상의 시험결과로 시험제제인 Citopcin®은 기준제제인 Ciprobay®와 생물학적 동등한 제제로 판단되었다. The pharmacokinetics of ciprofloxacin was studied for the evaluation of the bioequivalence of the generic ciproflocacin products. Two single doses of 500㎎ each of ciprofloxacin(Ciprobay® 250㎎ tablet as a reference compound and Citopcin® 250㎎ tablet s a test compound) were administered orally to ighteen male volunteers in a balanced, randomized crossover design. Pek plasma levels of ciprofloxacin were observed about 1 hour after the doses and the peak concentrations of both products were similar(Ciprobay®, 3.18㎍/㎖; Citopcin®, 2.89㎍/㎖). The values of other pharmacokinetic parameter of ciprofloxacin computed for Ciprobay® are presented in that order: AUC=13.53:12.47㎍·h/㎖, T_(max)=1.28:1.14 hours; MRT=5.30:5.08 hours; t_(1/2)β=3.65:3.47 hours. No satistically significant, differences were detected when AUC and the other parameters were compared with the method of ANOVA. Using the criteria of 90% confidence interval for the assessment of bioequivalence al the parameters were acceptable. The products were found to be equivalent on the premise that no significant difference was detected when the relevant pharmacokinetic parameters were compared, and the confidence limit analysis showed acceptable results.

열공형과 비열공형 피질하 혈관성 치매에서 위험인자의 차이에 관한 비교 연구

배희준,정지향,유경호,나덕렬,김상윤,최경규,양동원,손의주,이상도,김재우,박경원,김응규,이재홍,박미영,한일우,함동석,최문성,하충건,최성혜,이애영,이병철,한설희 대한치매학회 2003 Dementia and Neurocognitive Disorders Vol.2 No.2

Backgrounds and Objectives: Vascular dementia is a group of dementing disoders arising from various stroke syndrome. Among these. subcortical ischemic vascular dementia (SIVD) is regarded as a relatively distinct clinical entity. However, MRI patterns of SIVD are not homogenous. In some patients, lacunes are dominant, and in others, subcortical white matter changes are. This study was designed to compare risk factor profiles between SIVD with and without multiple lacunes. Methods: We divided 47 subjects (22 males, mean age. 68 years) recruited from VADAPET (Multicenter Trial For Evaluation Of The Changes In the PET Images Of Subcortical Vascular Dementia Patient) study into two groups one with more than 5 lacunes in deep gray matter (lacune group) and the other with 5 or less(non-lacune group) Clinical characteristics and laboratory findings of two groups were compared. Results: Nineteen of 47 patients (40%) belonged to the lacune group. The lacune and non-lacune groups d d not differ in the following variables: age, hypertension, diabetes mellitus, hyperlipidemia heart disease, history of stroke or TIA, history of trauma or major surgery, family history of hypertension stroke, or dementia, age at diagnosis of dementia, body mass index, white blood cell count, ESR, CRP, fibrinogen, hemoglobin A1C, total cholesterol. LDL cholesterol creatinine, proteinuria, glucosuria, and microhematuria. However, male sex, smoking alcohol. hemoglobin, and HDL cholesterol were possibly associated more with lacune group SIVD than with non-lacune group (p<0 1) Multivariate analyses revealed that smoking, hemoglobin, and HDL cholesterol were independent predictors of SIVD with multiple lacunes Conclusion: Our study suggests that SIVD with multiple lacunes may be significantly different in smoking habits hemoglobin, and HDL cholesterol from SIVD without multiple lacunes.

Dicyma sp. YCH-37이 생산하는 효모세포벽 용해효소 : 1. 생산균주의 분리 및 효소의 정제 l. Isolation of the Strain and Purification of the Enzyme

정희철,함병권,배동훈,하세가와토루,유주현 한국미생물생명공학회 ( 구 한국산업미생물학회 ) 1996 한국미생물·생명공학회지 Vol.24 No.4

효모세포벽 용해효소를 생산하는 균주를 토양으로부터 분리하였다. 본 균주에 대한 현미경 관찰 및 형태학적, 배양상의 특징을 검토한 결과 Dicyma sp.로 동정되어, 본 균주를 Dicyma sp YCH-37로 명명하였다. 세포에 아무런 처리도 가하지 않은 생균상태의 세균, 효모, 곰팡이에 대한 용균 spectrum을 측정한 결과, 세균 중에서는 Salmonella typhimurium을, 효모 중에서는 Torulopsis, Hansenula, Zygosaccharomyces rouxii 등을 잘 용해시켰으며, 가압증기살균 처리된 효모는 모두 용해시킬 수 있었다. 배양상등액을 yeast glucan을 이용한 affinity adsorption 및 DEAE-cellulose column chromatography로 정제한 결과, 13%의 수율과 204배의 정제도로 정제되었다. SDS-PAGE, gel filtration을 통해 분자량은 약 25,000 daltons임을 확인하였으며, 용균활성의 최적 pH와 온도는 각각 8.0과 50℃이고, pH 4.0~pH 10.0, 40℃까지 안정하였다. The strain YCH-37, which produces yeast cell wall lytic enzyme, was isolated from soil. From the microscopic observation, morphological and cultural characteristics, this strain was identified to fungus, Dicyma sp. So, we named this strain as Dicyma sp. YCH-37. The lytic enzyme effectvely lysed Salmonella typhimurium among intact living bacteria and Torulopsis, Hansenula, Zygosaccharomyces among intact living yeast, as well as autoclaved yeast strains. The yeast cell wall lytic enzyme was succesively purified to 204 folds with 13% yields through yeast glucan affinity adsorption and DEAE-cellulose column chromatography. The enzyme was identified to monomeric protein with molecular weight of 25,000 daltons from the results of SDS-PAGE and gel filtration. The optimum pH and temperature for the yeast lytic activity were 8.0 and 50℃, respectively. The enzyme was stale up to 40℃, and between pH 4.0~pH 10.0.