• Title/Summary/Keyword: power factor control

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Tyndallized Lactobacillus plantarum HY7712 Restores Whole-Body γ-Irradiation-Impaired Th Cell Differentiation in Mice

  • Jang, Se-Eun;Ko, Da-Bin;Ahn, Young-Tae;Sim, Jae-Hun;Kim, Cha Soon;Kim, Dong-Hyun
    • Journal of Microbiology and Biotechnology
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    • v.27 no.12
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    • pp.2237-2240
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    • 2017
  • In the present study, we investigated the effect of tyndallized HY7712 (tHY7712) on the expression of Th cell specific transcription factors and cytokines in whole-body ${\gamma}$-irradiated mice. Oral administration of tHY7712 strongly recovered the ${\gamma}$-irradiation-suppressed expression of helper T (Th) cell- and regulatory T cell-related transcription factors and cytokines, such as T-bet, Foxp3, IFN-${\gamma}$, TNF-${\alpha}$, and IL-10, and suppressed Th2 cell-associated transcription factor and cytokine GATA3 and IL-5, respectively. Furthermore, compared with the control, tHY7712 treatment also restored ${\gamma}$-irradiation-impaired natural killer and cytotoxic T cell activities against YAC-1 tumor cells to 97.8% and 98.6%, respectively.

A Study on the Deformation of the Moving Pressure Plate in a Balanced Type Vane Pump (압력 평형형 베인 펌프의 가동 압력판 변형에 관한 연구)

  • 한동철;조명래;박신희;최상현
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 1998.04a
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    • pp.277-285
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    • 1998
  • This paper presents the deformation characteristics of the moving pressure plate in a balanced type vane pump that widely used automotive power steering systems. Moving pressure plate can control the clearance between rotor and plate in accordance with load pressure variation; it always guarantees that pump to have optimal volumetric efficiency. In this paper, firstly, we calculate the acting force on the pressure plate, which is used to determine the angular position and load condition for analyzing the deformation of pressure plate. Secondary, finite element method is used for the deformation analysis. As results of acting force analysis, it is found that maximum difference of forces occurs at angular position 28$\circ$ from the small arc center of cam ring and load pressure is a dominant factor to affect acting force variation. The deformation of pressure plate increases as load pressure increases. At high load pressure, the deformation of pressure plate becomes larger than the initial clearance between rotor and plate. Therefore, it is required to design the plate for controlling the deformation.

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Growth of Nd:YAG single crystal by czochralski method and characteristics of laser generation (Czochralski 방법에 의한 Nd : YAG 단결정의 육성 및 레이저 출력특성)

  • 이상호;김한태;배소익;정수진
    • Korean Journal of Optics and Photonics
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    • v.9 no.3
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    • pp.175-180
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    • 1998
  • Nd:YAG single crystal widely used as solid state laser was grown by Czochralski method. <111> single crystal with 0.9at% of $Nd^{3+}$ was grown from the Czochralski furnace with a automatic diameter control system. The vertical temperature gradient in the liquid was the major factor that influence the crystal quality, and the crystal diameter was controlled by the home made computer program. The crystal boule with $\phi$50mm$\times$ι100mm effective size was cut, polished, and antireflection coated. The optical evaluation such as absorption spectrum, fluorescence spectrum coincide with typical features of Nd:YAG single crystal. The laser rod was assembled into the CW laser generator with a Kr lamp. The maximum CW laser output was 70 W and the threshold power and efficiency was 1.3kW and 1.64% respectively.

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Capacity Analysis on Cellular CDMA System with Adaptive Array Antenna in the Presence of Angle Estimation Error (각도추정 오차가 있는 경우 적응배열 안테나를 사용한 셀룰러 CDMA 시스템의 용량분석)

  • 정영모
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.25 no.6A
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    • pp.900-909
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    • 2000
  • Adaptive array antennas are one of the most promising techniques for improving the capacity of CDMA mobile communication system. In this paper, the uplink and downlink capacity for asynchronous W-CDMA system with adaptive array antenna is analyzed when an angle estimation error is present. From the results, it is found that the capacities are decreased by the angle estimation error. Specifically, when 5 degrees of error is present at 9 element adaptive array, the capacities are found to decrease by 5.2% in the uplink and 11.6% in the downlink. Also, in this paper, an attempt for comparing the capacities on different channel environments has been made. However, it is found that the increase of the Rice factor hardly effects the capacity due to the power control.

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Design of High-Efficiency Full-Bridge Converter and Inverter for ESS (ESS용 고효율 풀브리지 컨버터 및 인버터 설계)

  • Jung, Jae-Hun;Lee, Chang-woo;Choi, Jin-ku
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2015.05a
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    • pp.685-688
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    • 2015
  • A phase-shift full-bridge converter is widely used conventional converter. If the input power change in the variation of the output voltage, there is a time interval freewheeling according to a duty change. This is a factor of reducing the efficiency. In this paper, we propose a method for improving the efficiency of the converter/inverter systems that require high efficiency in the ESS. The proposed method was used for the duty control for solving the fail problem ZVS(Zero Voltage Switching) in Freewheeling interval. The proposed method was verified by experiments.

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The influence of pain experience upon dental fear (통증경험이 치과공포에 미치는 영향)

  • Ju, On-Ju;Park, Chung-Soon
    • Journal of Korean society of Dental Hygiene
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    • v.13 no.6
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    • pp.987-993
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    • 2013
  • Objectives : The aim of the study is to offer basic data that help to reduce dental fear by measuring adult dental fear level with DFS scale. Methods : The subjects were 300 persons including college students in W University and their parents in Jeollabuk-do Province. Data were collected by convenience sampling from May 1 to May 30, 2013. Results : 1. Dental clinic visit provoked pain in 99 people(47.4%). Oral examination and preventive treatment evoked pain in 13 people(6.2%). 2. Women tended to feel much pain than men. Both women and men felt the thrilling fear when a needle pricks the flesh. 3. Respondents having dental caries, gum bleeding, halitosis, shaking tooth, and painful tooth had a higher dental fear level. 4. The direct pain experience(p<0.001) had the greatest influence. The next influencing factor was the insufficient anesthesia(p<0.05). 5. The explanatory power that the pain experience has influence upon dental fear is $R^2$=0.151. Conclusions : The direct pain experience and the insufficient anesthesia experience have the great influence upon patients' dental fear level. Anesthetics and analgesics can be considered as one of the positive methods for pain control.

A study on the spray characteristics of CRDI system with injection pressure (분사압력에 따른 CRDI 분사계의 분무특성에 관한 연구)

  • KIM, Sang-Am;WANG, Woo-Gyeong;YANG, Jung-Kyu
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.52 no.1
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    • pp.65-71
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    • 2016
  • Injection rate, injection quantity and injection timing of fuel are controlled precisely by electric control in CRDI system. Particularly, injection rate being influenced with injection pressure affects to spray characteristics and fuel-air ratio, so it is a very important factor in diesel combustion. In this study, injection rates in accordance with injection pressure at a constant ambient pressure were measured with Zeuch's method. Under the same condition, non-evaporating spray images were taken with a high speed camera and analyzed carefully with Adobe Photoshop CS3. Macroscopic spray characteristics and breakup processes in the spray could be found from the examined and analyzed data. Injection start time and injection period were practically affected with injection pressure. Also, initial injection rate, spray penetration, spray angle and breakup of high density droplets region in the spray were affected with injection pressure. The results and techniques of spray visualization and injection rate measurement in this study would be practically effective to study a high pressure diesel spray for common rail direct injection system.

A Research of Power Factor Improvement using Phase Control of Active Harmonic Filter (고조파저감설비 위상제어를 통한 역률 향상에 관한 연구)

  • Choi, Won-kyu;Lee, Hwan;Jung, No-Geon;Jeon, Yeon-Ju;Kwon, Kyoung-min;Kim, Jae-Moon
    • Proceedings of the KIEE Conference
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    • 2015.07a
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    • pp.1609-1610
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    • 2015
  • 국내 철도 변전소의 부하전력은 부하인 철도차량의 부하특성에 의해 고조파와 역률이 매우 좋지 못한 실정이다. 이러한 이유에서 철도변전소에는 고조파를 보상하기위한 고조파 저감설비와 역률을 개선시키기 위한 역률보상용 콘덴서와 같은 전력품질개선설비(FACTs) 들이 설치되고 있다. 본 논문에서는 이러한 철도차량 부하의 차량별 고조파 특성을 살펴보고, 이를 효과적으로 제어할 수 있는 방법을 제안하였다. 제안된 알고리즘은 고조파저감설비의 위상제어를 통한 역률 향상을 도모하기 위한 것으로 일반적인 밴드패스 필터를 사용한 고조파 전류성분 검출에 따른 제어방식과 달리 고조파 전류에 대한 Lyapunov 안정도에 기반을 둔 제어방식을 적용하여 빠른 전류제어 동특성을 같도록 제안하였고 시뮬레이션과 실 부하 계통에 설치하여 운용함으로 그 타당성을 입증하였다.

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Fatigue Behavior of Welded Joints in HT60 Grade TMCP Steel (HT60급 TMCP강 용접부의 피로 거동)

  • Yong, Hwan Sun;Kim, Seok Tae;Cho, Yong Sik
    • Journal of Korean Society of Steel Construction
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    • v.8 no.4 s.29
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    • pp.133-133
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    • 1996
  • Application of the relationship $da/dN=C({\Delta}K)^{m}$ is effective in the analysis of fatigue crack growth life. The values of material constant C and m have great influences on the predicted fatigue life and the relationship between fatigue crack growth rate(da/dN) and stress intensity factor range(${\Delta}K$) is effective in fatigue crack growth behavior. In this paper, fatigue crack growth behavior of the welded joints in HT60 grade TMCP(Thermo Machanical Control Process) steel have been studied. To evalute the fatigue crack growth rates of HT60 grade TMCP steel, fatigue test was performed by base metal(BM), heat affected zone(HAZ) and weld metal(WM) in TMCP steel at room temperature. We determined the relationship of $da/dN-{\Delta}K$ by correlation between C and m obtained from the Paris-Erdogan power law data supplied HT60 grade TMCP steel. The obtained results from this study indicate that fatigue crack growth rate of TMCP steel is not influenced by softening effect which occurs in the HAZ when high heat input weld is carried out. Softening effects, which affect fatigue properties. are shown that it is not affected to the fatigue growth rates significantly.

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Design of FNN architecture based on HCM Clustering Method (HCM 클러스터링 기반 FNN 구조 설계)

  • Park, Ho-Sung;Oh, Sung-Kwun
    • Proceedings of the KIEE Conference
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    • 2002.07d
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    • pp.2821-2823
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    • 2002
  • In this paper we propose the Multi-FNN (Fuzzy-Neural Networks) for optimal identification modeling of complex system. The proposed Multi-FNNs is based on a concept of FNNs and exploit linear inference being treated as generic inference mechanisms. In the networks learning, backpropagation(BP) algorithm of neural networks is used to updata the parameters of the network in order to control of nonlinear process with complexity and uncertainty of data, proposed model use a HCM(Hard C-Means)clustering algorithm which carry out the input-output dat a preprocessing function and Genetic Algorithm which carry out optimization of model The HCM clustering method is utilized to determine the structure of Multi-FNNs. The parameters of Multi-FNN model such as apexes of membership function, learning rates, and momentum coefficients are adjusted using genetic algorithms. An aggregate performance index with a weighting factor is proposed in order to achieve a sound balance between approximation and generalization abilities of the model. NOx emission process data of gas turbine power plant is simulated in order to confirm the efficiency and feasibility of the proposed approach in this paper.

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