• 한국유기농업학회지
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• 제6권2호
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• pp.117-125
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• 1998

For isolation of antagonistic fungi antagonistic to Phytophthora capsici, a total of 157 isolates of fungi were screened from soil. Among the 157 isolates further screened by the dual culture test on potato dextrose agar and V-8 juice agar, 16 isolates were tested to show their antagonistic activity against P. capsici and Fusarium oxysporum. Fungal cul-ture filtrates of screened 16 isolates were shown to inhibit germination of zoospoorangia of P. capsici entirely and conidia of F. oxysporum considerably. Antagonistic fungi were shown to suppress of P. capsici infection of red-pepper plants maintained in the green house. Four isolates. 27 J5, 37 J10, 36 J13 and 31 K10, with the reduced disease incidence 53.3∼60.0% were identified as Fusarium sp. (27 J5). Trichoderma sp. (37 J10, 36 J13) and Penicillium sp. (31 K10).

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1169-1170
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• 2011

일반적으로 유도전동기를 구동시키기 위한 범용 인버터는 입력 전원에 정전이 발생하였을 경우 부하에 따라 수십 msec안에 저전압 트립이 발생하여 PWM 출력이 차단된다. 부하의 관성이 큰 경우 전원이 복구 되었을 때, 기존의 속도로 정상 가속하기 위해서는 부하가 완전히 멈춘 후 인버터를 구동시키고, 다시 큰 관성의 부하를 가속하는데 긴 시간이 필요하다. 본 논문은 유도전동기를 V/f 제어방법으로 운전하고 있는중에 정전이 발생했을 때 인버터의 출력을 차단하지 않고 연속적인 제어를 행하는 순간정전 보상 알고리즘방법으로서 부하의 관성 에너지를 인버터 직류단에 회생시키도록 출력 주파수를 제어하는 방법을 제안하고 실험을 통해 이를 검증하였다.

• 전기학회논문지P
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• 제60권4호
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• pp.253-256
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• 2011

LEDs have small size, long lifespan, high reliability, low power consumption and high color efficiency. Using such a characteristics, LED Back Light Unit has been studying actively. This paper proposes LED driver to minimize power consumption due to LED forward voltage($V_F$) difference and temperature rising. Compared to conventional LED driver, the proposed driver have excellent stability, brief structure and linear output voltage of DC-DC boost converter. Proposed LED Driver circuit was designed using 0.35um CMOS technology. And its operation was verified through simulation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.374-375
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• 2011

This paper presents a method to determine parameters of BTB (back-to-back) converters in terms of the enhancement of interface flow margins. Interface flow margin is by definition a measure of how much active power can be transferred from the external areas to the study area with the fixed load demand, and it is mainly constrained by system voltage stability. BTB converters are controllable equipments with the active power flow through them, and its DC link in fact can divide the AC systems at the location and hence can reduce the fault current level. This paper first cals margin sensitivities at the nose point of F-V curves and formulates an optimization problem to update the BTB parameters to improve the margins. This procedure is repeated performed until the required margin enhancement is achieved.

• Asian-Australasian Journal of Animal Sciences
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• 제8권1호
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• pp.29-35
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• 1995

A selection experiment with Romney Marsh sheep was used to evaluate correlated responses to selection. The selected flock was formed in 1979 by the Romney Group Breeders where selection was for prolificacy, defined as the number of live lambs born per ewe joined per year and a randomly selected control flock was established in 1982. Selection for prolificacy resulted in (i) increased ewe fertility, (ii) increased ewe ovulation rate, (iii) increased ewe litter size, (iv) decreased ewe body weight, (v) decreased lamb birth weight and (vi) decreased lamb 8-week weight. The rates of correlated responses per year respectively for ewe fertility, ewe ovulation rate, ewe litter size, ewe body weight, lamb birth weight and lamb 8-week weight were 0.033(0.002), 0.043(0.016), 0.019(0.005), -0.017(0.066), -0.055(0.025) and -0.150(0.057).

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(1)
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• pp.397-401
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• 2004

In this paper, Inverter drives adopting 3-phase and 2-phase SRP-PWM (Separately Randomized Pulse Position PWM) with fixed switching frequency is proposed. In the proposed SRP-PWM scheme, each of 3 or 2 phase pulses Is located randomly in each switching interval. The experimental results show that the voltage / current harmonics and the switching noise harmonics are spread to a wide band area. Also, the performance of the 3-phase SRP-PWM and the 2-phase SRP-PWM are compared to each other. In result, the speed response is nearly similar to each other from the viewpoint of the v/f constant control.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 하계학술대회 논문집
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• pp.171-173
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• 2008

스칼라 제어에 속하는 V/F 방식은 기본파 전압의 실효값과 주파수를 독립변수로 하여 평균적인 토크를 제어함으로 제어가 쉽고 구현이 간단하여 산업계에서 널리 쓰이고 있다. 그러나 주파수의 변화에 따라서 전동기 내부 임피던스도 변화하기 때문에 단순히 주파수만을 가변 하는 것만으로는 약계자에 의한 토오크 부족이나 과여자에 의한 여자 포화등에 의해 역률과 효율이 떨어진다. 또한 순시적인 토오크 제어가 불가능하여 전동기의 고성능 제어가 어렵다. 본 논문에서는 벡터제어를 적용한 엘리베이터 도어용 유도전동기 구동 시스템을 제안하고 실험을 통해 그 성능을 확인하였다.

• 한국통신학회논문지
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• 제25권6B호
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• pp.114-114
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• 2000

In this paper, a current comparative frequency automatic tuning circuit for the CMOS bandpass filter are designed with the new architecture. And also, when the designed circuit is compared the typical tuning circuit, it has very simple architecture that is composed of the current comparator and charge pump and operated in 2V power supply. The proposed tuning circuit automatically compensate the difference between the operating current of the integrator and the reference current which is specified. Using CMOS 0.25um parameter, a CMOS bandpass active filter with center frequency(f0= 100MHz) is designed, and according to the transister size the variation of the center frequency is simulated. As the HSPIC simulation results, the tuning operating of the proposed current comparative frequency automatic tuning circuit is verified.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 F
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• pp.2556-2558
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• 1999

We present voltage-source inverter for variable speed of washing machine. In the case of previous washing machines only on/off contol of motor was satisfied but these days the desire of customers moves to more silent and energy saving machine. Therefore many white goods manufacturers consider variable driving methods of motor. Nowadays variable speed Induction motors powered by inverters are becoming more and more popular. In this paper the principles of constant V/F control of Induction motor used in washing machine and space vector PWM technique are reviewd. Implementation issues such as command voltage generation, switching pattern determination, speed and power measurement are also presented. Experimental results are included in the end of the paper.

• 전자공학회논문지D
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• 제35D권7호
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• pp.40-47
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• 1998

This paper presents the physiological signal processing CMOS one chip for transmitting human bodys small electrical signals such as electrocardiogram(EKG) or electromyogram(EMG) and the external system for receiving signals was implemented by the commercial ICs. For simultaneous four-subject four-channel telemetry, a new enfored synchronization techniqeu using infrared bi-directional communication has been proposed. The telemeter IC with the size of 5.1*5.1mm$^{2}$ has the following functions: receiving of command signal, initialization of internal state of all functional blocks, decoding of subject-selection signal, time multiplexing of 4-channel modulated physiological signals, transmitting of telemetry signal to external system and auto power down control. The newly designed synchronized oscillator with low supply voltage dependence in the telemeter IC operates at a supply voltage from 4.6~6.0V and the nonlinearity error of PIM modulator was less than 1.2%F.S(full scale). The power saving block operates at the period of 2.5ms even if the telemetry IC does not receive command signal from external system for a constant time.