• The Journal of Korean Physical Therapy
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• 제35권2호
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• pp.43-47
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• 2023

Purpose: This study compared the movement control ability of the ankle joint according to the type of muscle contraction, namely, eccentric or concentric contractions. Methods: Thirty-four healthy adult subjects participated in this study. As a single group, before the experiment, the subjects were trained on achieving the required position of the ankle around the target point by manually controlling the ankle dorsiflexion by 10°. Concentric contraction starts at 0° and continues until the target point of 10° is reached. During an eccentric contraction, the ankle joint starts at 20° ankle dorsiflexion and continues till the target point is reached. Movements using eccentric contraction and concentric contraction were randomly performed 3 times each. Results: The results of comparing the difference in the movement control ability of each type of muscle contraction of ankle dorsiflexion showed that the measurement-remeasurement error was significant in eccentric contraction. Conclusion: In this study, we found a difference in the ability to control movement according to whether the contraction is eccentric or concentric. Therefore, we propose that the ability to control movement is affected by the type of muscle contraction.

• 전기의세계
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• 제20권6호
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• pp.7-18
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• 1971

Secondary-side transfer phenomena of primary-side surge voltage in concentric-cylindrical transformers of a high turn-ratio still present a problem in transformer insulation design even in the case of a neutral solid-grounding type. The conventional methods of analyzing them so far are much complicated for practical applications. Therefore, this paper describes a new approach to the analysis of secondary-side transfer phenomena of surge in concentric-cylindrical transformers of high turn-ratio and solid-grounding type. This generalized approach is thought to be more simple with the use of minor network concepts than the conventional one by major network only. The result shows that the secondary-side transfer phenomena of surge voltage could not be neglected even in concentric-cylindrical transformer of high turn-ratio and solid-grounding type, and will be satisfactorily applicable to the design of neutral-solid-grounding type transformers.

• 전기학회논문지
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• 제67권6호
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• pp.702-707
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• 2018

In case of Lighting occurs in Domestic combined distribution line, normally the voltage for the neutral line increase dramatically. General connection for underground cable is bundled common earth type so the lightning over voltage increase at the concentric-neutral line is not big enough to give impact on cable sheath. But in case of Non bundled common earth type it is necessary to analyze the phenomena on cable sheath caused by lightening overvoltage. Especially pole and cable joint are the core factor to consider. In this paper concrete pole and cable joint were evaluated in case of Non bundled common earth type combined distribution Line. EMTP simulation model has been designed and several case study were made. Also several experimental test were made to verify the simulation result.

• Physical Therapy Rehabilitation Science
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• 제5권1호
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• pp.40-46
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• 2016

Objective: The purpose of this study was to examine the effect on multifidus and external oblique abdominis muscle activation during hip contraction of three types (concentric, isometric, eccentric) in standing position. Design: Cross-sectional study. Methods: Twenty healthy adult men volunteered to participate in this study. Muscle activation was recorded from gluteus maximus, both multifidus, and both external oblique abdominis by surface electromyography (EMG) while holding position in the type of gluteus maximus contraction. EMG values were normalized by maximum muscle contractions (% maximum voluntary isometric contraction). All subjects performed hip extension with three contraction methods. The type of gluteus maximus contraction using Thera-band was composed of concentric contraction (type 1), isometric contraction (type 2), and eccentric contraction (type 3). To measure muscle activation on the gluteus maximus contraction type, each position were maintained for 5 seconds with data collection taken place during middle three seconds. Muscle activation was measured in each position three times. Results: For the results of this study, there was no significant difference within three contraction patterns of the gluteus maximus (concentric, isometric, and eccentric) each both multifidus, both external oblique abdominis, and gluteus maximus. And there was no significant difference among both multifidus, both external oblique abdominis, and gluteus maximus each hip extension contraction type. Conclusions: These findings suggest that specific contraction types of the gluteus maximus does not lead to a more effective activation of the multifidus, external oblique abdominis, and gluteus maximus.

• The Journal of Korean Physical Therapy
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• 제10권2호
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• pp.57-69
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• 1998

The role of eccentric muscle activities in functional everyday activities and sport is important and equally significant to concentric conditions. Eccentric and concentric exercise and evaluation are, therefore, very important. The purposes of this study were to measure eccentric md concentric peak torgue, percentage of peak torque, average power and percentage of average power of trunk flexors and extensors by using the Cybex NORM isokinetic dynamometer, and to standardize the value obtained. Thirty four young volunteers were tested, 17 females and 17 males, who had no history of back pain or abnormality. Each subjects were tested on three repetitions for isokinetic concentric and eccentric contraction at 5 velocities. The results were as follows; 1) Peak torque percent body weight of eccentric contraction were significantly greater than concentric contraction at each angular velocity and in trunk flexors and extensors(p<0.01). 2) Peak torque percent body weight of concentric contraction were significantly decreased as the angular velocity increased both male and female(p<0.01). 3) Peak torque percent body weight of eccentric contraction were not significantly changed as the angular velocity increased both male and female(p<0.05), 4) Peak torque percent body weight of male were significantly greater than female at each angular velocity and in concentric and eccentric contraction of trunk flexors and extensors(p<0.01)

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 춘계학술대회 논문집
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• pp.483-484
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• 2007

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1270-1272
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• 2005

This paper presents a method to reduce the back-emf THD(Total Harmonic Distortion) for the Concentric winding type Interior Permanent Magnet Synchronous Motor(CIPMSM). In the CIPMSM, many design variables and their complicated combinations must be considered to reduce the back-emf THD, but it requires a lot of time and efforts. Therefore, this paper suggests the optimized solution with two simple design parameters using MINITAB software.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1646-1651
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• 2004

This paper has been carried out to find the thermal efficiency and operating characteristics of heatpipe type solar collector using a glass concentric evacuated tube(CETC) during summer. In an experiment the flow rate of water in collector are 1.5l/min. Collector efficiency is $50{\sim}60%$ during time. The solar radiation appeared in a clear day is efficiency high. Efficiency curve fitted first order polynomial show that $F_{R}$$({\tau}{\alpha})$ and $F_{R}U_{L}$=1.316 is 0.601 and 1.316 respectively.

• 한국음향학회:학술대회논문집
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• 한국음향학회 2001년도 추계학술발표대회 논문집 제20권 2호
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• pp.379-382
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• 2001

In the muffler industry, the main purpose of the research works is to determine a way to increase the TL (Transmission Loss) properties of the muffler, without deteriorating the back pressure influence. In order to obtain better results, several works have been done by changing the geometrical characteristics of the muffler or the type of the muffler. This work will focus on the perforated muffler components with concentric chamber, to investigate the effect of a non-uniform porosity along the inner perforated tube of the muffler on the TL. It is noted that varying the perforation ratio affects the peaks frequencies of the TL, especially fer $2\pi < kL < 4\pi$ (in the case of L : 200mm for the concentric resonator). The magnitudes of the TL, for this range of frequencies, vary noticeably by changing the porosity distribution.

• 한국음향학회지
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• 제19권2호
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• pp.8-12
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• 2000

본 논문은 주위 환경인 수압 및 수온변화에 따른 맨드릴형 광-음향센서의 감도특성을 분석한 것에 관한 것이다. 음향감지부의 구조로는 실린더형, 중공 층상복합체형 및 air cavity가 삽입된 중공 층상복합체를 선정하고, 주위 수압과 수온변화에 따른 광-음향센서의 감도특성을 분석하였다. 맨드릴형 광-음향센서는 주위 정수압의 변화에 대해 0.15dB 미만의 음향감도 변화를 나타내고, 수압변화에 대해 안정적인 특성을 보유하고 있다. 주위 수온변화에 대한 음향감도의 상대적인 안정성은 air cavity가 삽입된 중공 나일론 층상복합체를 이용한 맨드릴형 광-음향센서가 가장 우수한 것으로 나타났다.