• Journal of Acupuncture Research
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• v.18 no.1
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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.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.68 no.1
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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.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.5
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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.

• Journal of the Korean Society for Library and Information Science
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• v.57 no.2
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• pp.97-122
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• 2023

Metaliteracy is a new framework that reframes information literacy. Metaliteracy is distinguished from information literacy through the intruduction of postmodernism, social constructivism and metacognition. However it has been not examined whether metaliteracy studies reflect the conceptual differences. Therefore, The purpose of the study is to observe research trends of metaliteracy on the difference from information literacy. In the study, literature reviews were conducted, and frequency analysis and knowledge network analysis(co-occurrence and bibliographic coupling) were conducted for 80 metaliteracy studies. The results of the study are as follows. As a result of co-occurrence analysis, metacognition(frequency 1st) and skills(degree centrality 1st, closeness centrality 1st, betweenness centrality 1st) appeared. Since metaliteracy criticizes skill-based information literacy, the result suggests that the concepts of information literacy and metaliteracy are mixed. On the other hand, as a result of bibliographic coupling analysis, studies with high bibliographic coupling explain the difference between information literacy and metaliteracy through metacognition.

• Journal of Acupuncture Research
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• v.23 no.6
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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.

• Proceedings of the KSME Conference
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• 2001.06b
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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.

• Journal of Korean Society for Quality Management
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• v.46 no.3
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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.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2008.04a
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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.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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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.

• Journal of the Korea Institute of Military Science and Technology
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• v.18 no.6
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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.