• Journal of Acupuncture Research
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• 제18권1호
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• pp.76-87
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• 2001

Objective : Zusanli(ST36) and Hoku(Li4) are analgesic acupuncture points frequently used for acupuncture in Oriental medicine. The present study was conducted to see the antinociceptive effects produced by electroacupuncture combined two frequencies(Low, High) and two different acupuncture points(LI4, ST36) in the rat tail flick test. Method : In this study the Rats (Sprague-Dawley, 250-300g) were partially anesthetized with thiopental sodium(40mg/kg, i.p.). The basal reaction time for the tail-flick was 3${\pm}$0.5 sec. Low frequency(3Hz, 5V, biphasic) and high frequency(100Hz, 5V, biphasic) were applied to the inserted needle for the period of insertion(twenty minutes). Experimental groups are divied as follow; a) electroacupuncture stimulation groups at Hoku with or high frequency(L-EA, H-EA), b) electroacupuncture stimulation groups at Zusanli with low or high frequency(1-EA, h-EA), c) low frequency at Hoku and Zusanli(LIEA), d) low frequency at Hoku and high frequency at Zusanli(LhEA), e) high frequency at Hoku and low frequency at Zusanli(HIEA), f) high frequency at Hoku and Zusanli(HhEA) Results : The individual stimulation at either Hoku or Zusanli with low frequency has stronger and longer analgesic effect than high frequency stimulation. In addition, the combined stimulation at Hoku and Zusanli with low frequency has superior effect to individual stimulation with low frequency. LhEA and LIEA have superior effect to other stimulation groups among the combined groups. In order to determine the involvement of opioid system on the different antinociceptive effects, Naloxone, an opioid antagonist, was used in the combined groups. LIEA is the most sensitive when naloxone was administrated among study groups. HhEA is the least sensitive in the administration of naloxone. Conclusion : From results, this study confirmed that the opioid system is involved in analgesic effect of low frequency stimulation of acupuncture point, and we also can suggest the stronger analgesic effect of combining stimulation points is due to the theory of spatial summation in the nervous system.

• 전기학회논문지
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• 제68권1호
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• pp.8-12
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• 2019

Combined Cycle Unit(CC) generates the primary power from the Gas Turbine(GT) and supplies the remaining heat of the GT to the Steam Turbine(ST) to generate the secondary power from the ST. It plays a major role in terms of energy efficiency and Load Frequency Control(LFC). Incremental Heat Rate(IHR) curves of economic dispatch(ED) of CC is applied differently by GT/ST combination. But It is practically difficult because of performance test by all combinations. This paper suggests a reasonable method for estimating IHR curves for partial combinations(1:1~(N-1):1) using IHR curves when operating with GT alone(1:0) and with all(N:1) combinations of CC.

• 한국전기전자재료학회논문지
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• 제17권5호
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• pp.502-507
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• 2004

The forward planar transformer, which had power capacity of 300 W, input voltage of 220 V, output voltage of 15 V, and switching frequency of 300 KHz, was designed and manufactured by using the planar core with large effective area and the flat copper leadframes for miniaturization and high efficiency of the switching mode power supply (SMPS). As well as, a forward converter equipped with the above mentioned planar transformer was manufactured and electromagnetic characteristics were investigated. The numerical value of turns for 1st and 2nd winding were 15 and 2 respectively The self inductance of 1st winding was 1.592 mH, very low leakage inductance of 2.7 $\mu$H, and the coupling factor of 0.928 were obtained at switching frequency of 300 KHz. The high efficiency of 88.62 % for the SMPS equipped with planar transformer was obtained at power capacity of 300 W.

• 한국문헌정보학회지
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• 제57권2호
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• pp.97-122
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• 2023

메타리터러시는 정보 리터러시의 재구조화된 결과물이다. 메타리러러시는 포스트모더니즘, 사회적 구성주의, 메타인지의 도입을 통해 정보 리터러시와 구분되었다. 그러나 메타리터러시 연구들이 이 개념적 차이를 반영하고 있는지는 검토되지 않았다. 따라서 이 연구의 목적은 메타리터러시 이론을 연구한 학술논문들에서 이 개념적 차이를 어떻게 반영하고 있는지 연구동향을 관찰하는 것이다. 이 연구는 문헌연구를 실시하고, 메타리터러시 연구 80편을 대상으로 빈도분석 및 지식 네트워크 분석(동시출현·서지결합)을 실시하였다. 결과는 다음과 같다. 동시출현분석 결과, 메타인지(빈도 1위)와 더불어 스킬(연결중심성 1위, 근접중심성 1위, 매개중심성 1위)로 나타났다. 메타리터러시는 스킬 기반의 정보 리터러시를 비판하기 때문에 이 결과는 정보 리터러시와 메타리터러시 개념이 혼재되어 있음을 시사한다. 한편 서지결합분석 결과, 서지결합도가 높은 논문은 정보 리터러시와 메타리터러시의 차이를 메타인지를 통해 설명하고 있다.

• Journal of Acupuncture Research
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• 제23권6호
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• pp.207-219
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• 2006

Objectives : This study was to investigate the effect of low frequency electro-acupuncture (EA) at ST36 acupoint on the Freund's Complete Adjuvant(FCA)-induced arthritis in rats. Methods : Arthritis was induced by intradermal injection of FCA into base of tail. Experimental groups were divided into 4 groups; Normal, Control, ST36 and Non-Acupoint(NA). ST36 group was treated by 2 Hz EA at ST36 acupoint. Body weight, paw edema volun1e and ankle joint thickness were measured after treatment. And we investigated the effects of 2 Hz EA via WBC count, segment neurophil, lymphocyte, PGE2 assay and NADPH-d histochemistry. Results and Conclusion : The mean of body weight and ankle joint thickness of ST36 group was increased compared with control group. The mean of paw edema volume, WBC count, segment neutrophil and lymphocyte of were not decreased with control group. The mean of PGE2 concentration and NADPH-d positive neurons were changed significantly compared with control group.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.366-371
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• 2001

Dynamic stability of an oscillating cantilever plate is investigated in this paper. The equations of motion include harmonically oscillating parameters which originate from the motion-induced stiffness variation. Using the multiple scale perturbation method is employed to obtain a stability diagram. The tability diagram shows that relatively large unstable regions exist when the frequency of oscillation is near twice the frequencies of the 1st torsion natural mode and the 1st chordwide bending mode.

• 품질경영학회지
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• 제46권3호
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• pp.641-650
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• 2018

Purpose: This article provides a cause of breakage and a method for improving reliability of the headlight system installed in the main battle tank K2. Method: The natural frequency of the headlight system is estimated by using the finite element method. In addition, the allowable stress level under the severe conditions is provided through vibration test of a single item and a system level. Results: Based on the finite element analysis and the vibration test in the frequency domain, the lamp of the left headlight system fails by the resonance effect. Conclusion: For improving the reliability of the headlight system, the thickness of protector frame is increased to avoid the resonance effect.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2008년도 정기 학술대회
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• pp.555-560
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• 2008

Dynamic interaction analysis between actively controlled Maglev and bridge is carried out. For this, dynamic governing equation for 2-dof Maglev vehicle and optimal feedback control scheme of DOFC are developed. And then the dynamic effect of the 1st natural frequency of bridge, vehicle/bridge mass ratio and damping coefficient of bridge to the both of air-gap variations of UTM-01 maglev vehicle and bridge center maximum displacement response are investigated. From the results of numerical simulation, it is found that the 1st natural frequency of bridge, vehicle/bridge mass ratio and damping coefficient of bridge does not affect greatly within design velocity of the vehicle.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1394-1397
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• 2005

The object of this study was to design of micro stage, which is one of the equipments embodied in ultra precision positioning mechanism. Design factors for micro stage were decided a roundness of hinge, a thickness of hinge, a thickness of stage, a length of arms and a clearance of division. To obtain the $1^{st}$ natural frequency and equivalent stresses, FEM simulation was performed using the table of orthogonal arrays and Taguchi method was used to determine the optimal design parameters. As results of this study, the size of 1st natural frequency and equivalent stresses on micro stage was influenced significantly by a thickness of hinge and a length of arm.

• 한국군사과학기술학회지
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• 제18권6호
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• pp.808-815
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• 2015

For performance improving of C-band radar altimeter used in a missile system, Ku-band radar altimeter is developed. To utilize the time delay devices which are used in testing C-band radar altimeter, we proposed C-band and Ku-band frequency conversion method and implemented it as a part of missile system test equipment. In this paper we present design contents, development results and test application results of radar altimeter test equipments.