• 한국소음진동공학회논문집
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• 제14권6호
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• pp.528-535
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• 2004

Ultrasonic Vibrator is designed to achieve the maximum vibration amplitude at 30 kHz by in-cluding a horn (diameter, 40 mm), mechanical vibration amplifier at the top of the ultrasonic vibrator in the system and making the complete system resonate. In addition, it is experimentally visualized by particle imaging velocimetry (PIV) that the acoustic streaming velocity in the gap is at maximum when the gap between the ultrasonic vibrator and stationary plate agrees with the multiples of half-wavelength of the ultrasonic wave. This fact results from the resonance of the sound wave and the theoretical analysis of that is also accomplished and verified by experiment. It is observed that the magnitude of the acoustic streaming dependent upon the gap between the ultrasonic vibrator and stationary plate possibly changes due to the measurement of the average velocity fields of the acoustic streaming induced by the ultrasonic vibration at resonance and non-resonance. There exists extremely small average velocity at non-resonant gaps while the relatively large average velocity exists at resonant gaps compared with non-resonant gaps. It also reveals that there should be larger axial turbulent intensity at the hub region of the vibrator and at the edge of it in the resonant gap where the air streaming velocity is maximized and the flow phenomena is conspicuous than that at the other region. Because the variation of the acoustic streaming velocity at resonant gap is more distinctive than that at non-resonant gap, shear stress increases more in the resonant gap and is also maximized at the center region of the vibrator except the local position of center (r〓0). At the non-resonant gap there should be low values of vorticity distribution, but in contrast to the non-resonant gap, high and negative values of it exist at the center region of the vibrator with respect to the radial direction and in the vicinity of the middle region with respect to the axial direction. Acoustic streaming is noise-free due to the ultrasonic vibration and maintenance-free because of the absence of moving parts. Moreover, the proposed method by acoustic streaming can be utilized to the nano and micro-electro mechanical systems as a driving mechanism in addition to the augmentation of the streaming velocity.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 센서 박막재료 반도체 세라믹
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• pp.223-227
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• 2003

In this study, ultrasonic rotary motors using a bolted langevin type ultrasonic vibrator were designed and fabricated. The stator vibrator has a longitudinal transducer section composed of two metal blocks and two piezoelectric ceramic elements (thickness-polarized) and a mode conversion metal block section called a torsion coupler. And, three kinds of motors were studied by finite element analysis and experiments. So, as material of torsion coupler which generate mode conversion of vibration copper, brass, and phosphor bronze were used. As a result, speed and torque were changed in proportion to the electrical input Voltage, but it was saturated in high voltage. And bad efficiency which was different from a expectation was measured in this motors. So, various problems should be improved for practical use. Finally, The motor which has 1 [cm] diameter was fabricated to present a possibility of miniaturization of this type motors.

• 대한의료기공학회지
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• 제22권1호
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• pp.1-27
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• 2023

Objective : This paper provides a narrative review of the research literature on the neurophysiological and neurochemical mechanisms of local vibration while studying the treatment principles and mechanisms of Whidam's vibrator Sugi therapy. Methods : Searches related to vibration therapy research were conducted in PUBMED using "Vibration", "Whole Body Vibration", "Localized Vibration", and "Focal Vibration". The Conditions were limited to review and systematic review. Results : Roberto Casale's paper was selected as an inquiry task and reviewed critically and narratively by referring to other papers. The stimulation process of local vibration (LV) was broadly classified into receptor transmission (pain reception phase), ascending sensory pathway to the spinal cord (segmental phase), and action of the cortex and subcortical structures (systemic control phase) according to the pain pathway. In addition, the role of C-tactile mechanoreceptors, changes in neurotransmitters and neurohormones, LV stimulation below perception threshold (lower threshold), pain control and kinesiologic illusions were specially addressed. In addition, the expression and function of Piezo Channels were added to supplement the human pain and tactile sensing mechanism. Conclusions : LV exerts pain control mechanisms through different interactions that can interfere with pain transmission and pain perception. Since LV provides sufficient neurophysiological reasons for clinical application, it is necessary to expand the use of Whidam's vibrator Sugi therapy to a wider range of clinical applications.

• 대한통합의학회지
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• 제4권1호
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• pp.85-97
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• 2016

Purpose : The purpose of this study was to investigate the effects on the muscle thickness and contraction time using sound wave vibrator and swiss ball. Methods : This study was performed on 20 subjects. 20 subjects were divided into two groups; Lumbar stability exercise using sound wave vibrator exercise(n=10)(Group1), Lumbar stability exercise using Swiss ball exercise(n=10)(Group2). Both of the group performed the exercise 3 times a week for 5 weeks. The data was analyzed by the paired t-test to compare before and after difference of factors on each group and the Independent t-test to compare the between groups. Results : Both group were increased muscle contracture time on Straight Leg Rise(SLR) test (p<0.05). It means both group were increased lumbar stability. However, by comparing the between groups, there were no statistically significant difference about muscle thickness of multifidus and transverse abdominal.(p>0.05). Conclusion : As a result of this study, we suggest that the sound wave vibrator may be effective exercise tool for lumbar stability exercise like a swiss ball.

• 한국음향학회지
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• 제37권1호
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• pp.46-52
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• 2018

압전변압기에 사용되는 압전 단결정은 높은 입력 임피던스로 인하여 파워전송용량이 높지 않다는 문제점이 있다. 따라서 본 연구에서는 연산증폭기를 사용한 범용 임피던스 변환(General Impedance Convert, GIC) 회로로 구현된 정전용량 증가회로를 압전 단결정 진동자의 전기단자에 연결함으로써 입력임피던스를 저하시켜 파워전송용량을 향상시킬 수 있는 방법을 제안하였다. $128^{\circ}$회전 Y판 $LiNbO_3$ 단결정 진동자에 설계 제작된 정전용량 증가회로를 적용하여 구동 특성을 측정한 결과, 입력임피턴스는 25 % 감소, 전기-기계결합계수는 30 % 증가, 전압변환 특성에 있어서는 약 17~30배의 출력파워용량이 증가됨을 확인하였다.

• 한국음향학회지
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• 제36권3호
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• pp.158-164
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• 2017

수중에서 은밀하게 움직이는 표적을 조기에 탐지하기 위한 선배열센서에 적용되는 통상의 하이드로폰은 표적신호의 크기만 측정할 뿐, 외부에서 들어오는 음향신호의 방향은 파악할 수 없는 한계가 있다. 이에 본 연구에서는 표적으로부터의 음향신호의 크기와 방향을 동시에 탐지할 수 있는 관성형 벡터 하이드로폰의 기본 구성품으로 두께 전단형 진동자를 제안하였다. 외력에 대한 진동자의 출력 전압을 해석할 수 있는 수식을 유도하였으며, PMN-PT 단결정 진동자에 대한 유한요소해석을 통해 수식의 타당성을 검증하였다. 본 연구에서 얻어진 해석 결과는 향후 두께 전단형 진동자로 구성된 관성형 벡터 하이드로폰 설계에 활용될 것이다.

• 한국음향학회지
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• 제36권3호
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• pp.165-171
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• 2017

유체로 채워진 원통형 압전진동자 내부에서 중심축으로 집속되는 음파에 대해 진동자 내부에 삽입된 동심원의 고체튜브가 음장분포에 미치는 영향을 해석하였다. 원통형 압전진동자의 내부로부터 방사된 음파는 유체매질을 지나 고체튜브의 벽면에서 반사 및 투과를 하여 중심축에 집속된다. 이때 고체튜브의 음향임피던스 및 두께 등에 의해 중심에 집속되는 음장 분포가 변한다. 이를 이론적으로 해석하기 위하여 각 매질에 대한 전달행렬을 도출하였고 이를 적용하여 중심축에서의 음압수준을 이론적으로 해석하였다. 여러 가지 두께를 갖는 아크릴 튜브에 대해서 중심축 상에서 측정한 음압수준의 변화는 이론해석의 결과와 잘 일치하였으며 중심에 형성되는 음압은 고체튜브의 두께에 따라 매우 민감하게 변화함을 확인하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.265-271
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• 1997

A bond graph modeling approach which is equivalent to a finite element method is formulated in the case of the piezoelectric thickness vibrator. This formulation suggests a new definition of the generalized displacements for a continuous system as well as the piezoelectric thickness vibrator. The newly defined coordinates are illustrated to be easily interpreted physically and easily used in analysis of the system performance. Compared to the Mason equivalent circuit model, the bond graph model offers the primary advantage of physical realizability. Compared to circuit models based on standard discrete electrical elements, the main advantage of the bond graph model is a greater physical accuracy because of the use of multiport energic elements. While results are presented here for the thickness vibrator, the modeling method presented is general in scope and can be applied to arbitrary physical systems.

• 한국전기전자재료학회논문지
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• 제31권3호
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• pp.152-155
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• 2018

Ultrasonic wave technologies have been widely used in ultrasonic washing machines, ultrasonic surgery, ultrasonic welding machines, ultrasonic sensors, and medical instruments. Ultrasonic surgery can be realized through the cavitation effect of ultrasonic waves. In this study, piezoelectric ceramics were manufactured to achieve the optimum design of a piezoelectric vibrator in a handheld generator for ultrasonic surgery. The best specimen showed the excellent piezoelectric properties of kp＝0.624, Qm＝1,531, and $d_{33}=356pC/N$. Numerical modeling based on the finite element method was performed to find the resonance frequency, the anti-resonance frequency, and the displacement properties of the handheld ultrasonic generator. Maximum displacement was observed in the six-step piezoelectric vibrator at $6.36{\mu}m$.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제53권3호
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• pp.123-127
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• 2004

Mode conversion type ultrasonic rotary motor using bolt tightened Langevin type vibrator was studied. Driving frequency of the motor, displacements and elliptical trajectories at tip of the coupler were simulated by finite element analysis program (ANSYS). Speed and torque of the fabricated motor were measured as functions of input voltage and load. As results, from FEA the driving frequency of 40.8[kHz] and useful elliptical trajectories were found. Fabricated motor rotated clockwise at frequency of 38.2[kHz]. Speed and torque of the motor were increased when the input voltage was increased. Maximum speed, torque and efficiency were 75[rpm], 0.14[Nm] and 6.28[％], respectively.