• 한국진공학회지
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• 제20권4호
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• pp.276-279
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• 2011

약밀려남/잡아당김/급냉각의 연속적인 압출 공정을 이용하여 대면적 불화 고분자 막을 제작하였다. 제안한 방법으로 형성된 불화 고분자 박막은 $C_i=2.9\;nF/cm^2$의 전기용량밀도가 측정되었고, 1kHz에서의 ${\varepsilon}_r$=56의 높은 유전상수를 나타내었다. $1.5406{\AA}$의 파장에서 Bruker AXS X-ray 회절분석기를 통해 $18.0^{\circ}$에서 최고점을 나타내어 전기변형 성능에 적합한 ${\beta}$ 상태를 확인하였다. 본 연구는 넓은 면적의 인공근육에 응용 가능한 전기변형 불화고분자막의 새로운 박막 형성 기술로 이용될 수 있다.

• 비파괴검사학회지
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• 제27권6호
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• pp.541-549
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• 2007

This work describes an investigation into the feasibility of using an acoustic emission (AE) technique to evaluate the integrity of a composite actuator with a PZT ceramic under electromechanical cyclic loading. AE characteristics have been analyzed in terms of the behavior of the AE count rate and signal waveform in association with the performance degradation of the composite actuator during the cyclic tests. The results showed that the fatigue cracking of the composite actuator with a PZT ceramic occurred only in the PZT ceramic layer, and that the performance degradation caused by the fatigue damage varied immensely depending on the existence of a protecting composite bottom layer. We confirmed the correlations between the fatigue damage mechanisms and AE signal types for the actuators that exhibited multiple modes of fatigue damage; transgranular micro damage, intergranular fatigue cracking, and breakdown by a short circuiting were related to a burst type signal showing a shortly rising and slowly decaying waveform with a comparably low voltage, a continuous type signal showing a gradual rising and slowly decaying waveform with a very high voltage and a burst and continuous type signal with a high voltage, respectively. Results from the present work showed that the evolution of fatigue damage in the composite actuator with a PZT ceramic can be nondestructively identified via in situ AE monitoring and microscopic observations.

• International journal of advanced smart convergence
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• 제12권3호
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• pp.211-220
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• 2023

Surface electromyography (sEMG) is a noninvasive method used to capture electrically muscle activity, which can be easily measured even during exercise. The basic unit of muscle activity is the motor unit, and because an sEMG signal is a superposition of motor unit action potentials, analysis of muscle activity using sEMG should ideally be done from the perspective of motor unit activity. However, conventional techniques can only evaluate sEMG signals based on abstract signal features, such as root-mean-square (RMS) and mean-power-frequency (MPF), and cannot detect individual motor unit activities from an sEMG signal. On the other hand, needle EMG can only capture the activity of a few local motor units, making it extremely difficult to grasp the activity of the entire muscle. Therefore, in this study, a method to visualize the activities of motor units in a single-channel sEMG signal by relocating wavelet coefficients obtained by redundant discrete wavelet analysis is proposed. The information obtained through this method resides in between the information obtained through needle EMG and the information obtained through sEMG using conventional techniques.

• 한국전문물리치료학회지
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• 제25권4호
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• pp.27-36
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• 2018

Background: We developed a novel integrative lumbar stabilization technique that combines lumbar extension (LE) exercise with abdominal drawing-in maneuver (ADIM) to ameliorate low back pain (LBP) associated with neuromuscular imbalance and instability, based on the collective evidence of contemporary spinal rehabilitation. Objects: The specific aim of the present study was to investigate the effects of LE exercise with and without ADIM on core muscle strength, lumbar spinal instability, and pain, as well as functional characteristics in individuals with LBP using advanced radiographic imaging techniques. Methods: patients with mechanical LBP (N = 40, 6 males; $35.1{\pm}7.6years$) were recruited and randomly assigned either to the combined LE and ADIM (experimental group) or the LE alone (control group). Outcome measures included the visual analog scale, the modified Oswestry Disability Index, muscle strength imbalance (MSI), and radiographic imaging. The lumbar intervertebral displacement (LID), intervertebral (IV) and total lumbar extension (TLE) angles were calculated to evaluate the lumbar segmental instability. Results: The experimental group showed significant differences in the L3-L4, L5-S1 LIDs, L4-L5 and L5-S1 IV angles, and TLE angle as compared to the controls (p<.05). Immediate pain reduction and muscle strength imbalance ratio were significantly different between the groups (p<.05). Conclusion: These results suggest that the addition of ADIM significantly increased lumbar spinal stabilization in individuals with LBP, thereby reducing pain associated with functional lumbar flexion during daily activities.

• 대한기계학회논문집A
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• 제31권1호
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• pp.36-42
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• 2007

This paper presents mechanical design, fabrication and test of a biomimetic fish robot actuated by a unimorph piezoceramic actuator, LIPCA(Lightweight Piezo-Composite curved Actuator.) We have designed a linkage mechanism that can convert bending motion of the LIPCA into the caudal fin movement. This linkage system consists of a rack-pinion system and four-bar linkage. Four types of artificial caudal fins that resemble caudal fin shapes of ostraciiform subcarangiform, carangiform, and thunniform fish, respectively, are attached to the posterior part of the robotic fish. The swimming test under 300 $V_{pp}$ input with 0.6 Hz to 1.2 Hz frequency was conducted to investigate effect of tail beat frequency and shape of caudal fin on the swimming speed of the robotic fish. At the frequency of 0.9 Hz, the maximum swimming speeds of 1.632 cm/s, 1.776 cm/s, 1.612 cm/s and 1.51 cm/s were reached for fish robots with ostraciiform, subcarangiform carangiform and thunniform caudal fins, respectively. The Strouhal number, which means the ratio between unsteady force and inertia force, or a measure of thrust efficiency, was calculated in order to examine thrust performance of the present biomimetic fish robot. The calculated Strouhal numbers show that the present robotic fish does not fall into the performance range of a fast swimming robot.

• 드라이브 ㆍ 컨트롤
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• 제18권4호
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• pp.77-83
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• 2021

With the progress in virtual reality technology, various virtual objects can be displayed using head-mounted displays (HMD). However, force feedback sensations such as pushing against a virtual object are not possible with an HMD only. Focusing on force feedback, desktop-type devices are generally used, but the user cannot move in a virtual space because such devices are fixed on a desk. With a wearable force feedback device, users can move around while experiencing force feedback. Therefore, the authors have developed a wearable force feedback device using a magnetorheological fluid clutch and pneumatic rubber artificial muscle, aiming at presenting the elasticity, friction, and viscosity of an object. To date, we have developed a wearable four-degree-of-freedom (4-DOF) force feedback device and have quantitatively evaluated that it can present commanded elastic, frictional, and viscous forces to the end effector. However, sensory evaluation with a human has not been performed. In this paper, therefore, we conduct a sensory evaluation of the proposed method. In the experiment, frictional and viscous forces are rendered in a virtual space using a 4-DOF force feedback device. Subjects are asked to answer questions on a 1- to 7-point scale, from 1 (not at all) to 4 (neither) to 7 (strongly). The Wilcoxon signed rank test was used for all data, and answer 4 (neither) was used as compared standard data. The experimental results confirmed that the user could feel the presence or absence of viscous and frictional forces. However, the magnitude of those forces was not sensed correctly.

• The Journal of Korean Physical Therapy
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• 제14권3호
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• pp.74-91
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• 2002

This studies to investigate the effects of ultrasound and swimming on the changes of the serum creatine kinase, latate dehydrogenase, aspatate aminotransferase, alanine aminotransferase, alkaline phosphatase, in peripheral nerve and muscle injury rats. The forty Sprague-Dawley adult male rats were assigned to the 4 groups: the experimental groups(3), and the peripheral nerve and muscle injury control group(1). There was made artificial injured by ischial nerve and muscle of each rats the each experimental ultrasound group and swimming group were treated from 3 days after being injuried for the 5 minutes and 10 minutes every day during the 10 days and 16 days respectively. The results were as follows: 1. The activities of creatine kinase, lactate dehydrogenase were significantly decreased on of the ultrasound and swimming groups for 10 days. All experimental group were significantly decreased for 16 days. there were significantly decreased the swimming group and ultrasound group were to the 10 days group. 2. The activities of asparatate aminotransferase, alalnine aminotransferase on the ultrasound group were significantly increased to the injured control group, there were significantly decreased the ultrasound group for 16 days group were to the 10 days group and there were significantly increased the swimming group for 16 days group were to the 10 days group. 3. The activities of alkaline phosphatase changes were no difference all experimental groups, there were significantly increased for 16 days group to the 10 days group. From these results it may be concluded that the effects of the ultrasound and swimming, the changes of the serum activities creatine kinase , lactate dehydrogenase of (; the objective indicates) to the muscle regeneration process of the nerve and muscle injured rats.

• 한국치위생학회지
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• 제9권4호
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• pp.824-835
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• 2009

Objectives : The purpose of this study was identified about oral health status and oral health needs of elderly. Moreover this study would be based further research of development of oral health in elderly. Methods : This study was undertaken to determine the oral health status and the need of oral management of over 65years elderly who were with dental prosthesis in elderly welfare center and Kyung Ro Dong in Kyung Bok and Kyung Nam. The results were as follows. Results : The sample was 200 participants. The demographical characteristic were that 74.0% of participant was female, 29.0% of participant was 75~79 years old, 42.5% of participant was under elementary, and 45.5% of participant was living alone. 43.7% of participant was pain from muscle-skeletal disease, 37.1% of participant was cardiac-vascular disease, and 31.1% of participant was ophthalmic disease. In oral health status, 54.5% of participant was partly artificial tooth and 45% of participant was whole artificial tooth. 78.0% of participant used under 10 years with partly artificial tooth and only 27.4% were satisfaction with artificial tooth. 83.5% of participant used under 10 years with whole artificial tooth and only 26.4% were satisfaction with artificial tooth. In the oral health status of partly artificial tooth, the average of toothbrush was 2 times, 42.2%. The majority method of toothbrush was 'their own freely' 55.0%. The time of toothbrush was 'after meal' 81.8%. The study result showed that majority participant didn't experience of tongue brush, regular examination, scaling, and oral health education. In the need of oral management with the whole artificial tooth, the participant who used longer artificial tooth was significantly higher about artificial irrigation and the method of management(p<.05). The need of participant who answered 'don't gum massage', was higher of xerostomia treatment(p<.01) and halitosis treatment(p<.05). In the need of oral management with the partly artificial tooth, the participant who used longer artificial tooth was significantly higher about regular examination(p<.01), oral cavity massage(p<.05), scaling(p<.05), dental caries treatment(p<.01). The need of participant who answered 'don't satisfaction with artificial tooth' was higher of regular examination and scaling(p<.05). Conclusions : Oral management needs of elderly who kept artificial tooth or denture required were regular dental examination, xerostomia management, management of artificial tooth and irrigation, and management of bad breath. This results meaned the oral health intervention program for elderly was developed regularly.

• 전기학회논문지
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• 제66권5호
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• pp.843-850
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• 2017

The EMG amplitude estimator, which has been investigated as an indicator of muscle force, is utilized as the control input to artificial prosthetic limbs. This paper describes an application of the optimal EMG amplitude estimator to the surface EMG signals recorded during constant isometric %MVC (maximum voluntary contraction) for 30 seconds and reports on assessing performance of the amplitude estimator from the application. Surface EMG signals, a total of 198 signals, were recorded from biceps brachii muscle over the range of 20-80%MVC isometric contraction. To examine the estimator performance, a SNR(signal-to-noise ratio) was computed from each amplitude estimate. The results of the study indicate that ARV(average rectified value) and RMS(root mean square) amplitude estimation with forth order whitening filter and 250[ms] moving average window length are optimal and showed the mean SNR improvement of about 50%, 40% and 20% for each 20%MVC, 50%MVC and 80%MVC surface EMG signals, respectively.

• 근관절건강학회지
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• 제24권3호
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• pp.187-195
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• 2017

Purpose: The purpose of the study was to identify the attributes of rapport, their antecedents and consequences. Methods: Walker and Avant's method for concept analysis was used to analyze the concept. Articles published from January 2007 to May 2017 were searched through PubMed, CINAHL, and RISS databases using "rapport" as a keyword. Results: The attributes of rapport were as follows: 1) understanding; 2) sharing information; 3) empathy; 4) harmonious relationship. The antecedents of rapport were as follows: 1) effective communication skills; 2) relation-oriented attitude. The consequences of rapport were forming trust, therapeutic relationship, improvement of quality of care, increased patients satisfaction and increased nurses satisfaction. Conclusion: Rapport can be defined as a harmonious relationship that understand each other and share ideas and information.