• 제목/요약/키워드: ultrasonic property

검색결과 177건 처리시간 0.029초

2-유체 분무에서 액체미립화에 대한 초음파의 영향에 관한 연구 (A Study on Ultrasonic Effects for the Atomization in a Twin-Fluid Spray)

  • 주은선;정진도;송민근
    • 한국분무공학회지
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    • 제3권4호
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    • pp.50-57
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    • 1998
  • The utilization of resonance should be considered to get the maximum effect of ultrasonic to atomize liquid. The ultrasonic generator, transducer, horn, and all attached parts are used to produce the resonance, and specially the characteristics of liquids such as liquid load, property, and etc., for the liquid atomization affinity are considered. In this study, the variable device of liquid load was made and distilled water and city water selected as experimental liquids were sprayed by a twin-fluid spray method and their diameters, distributions, and spray quantum of spray droplets were measured by the light scattering system. And all data were observed, compared and considered relatively. In results, a lot of phenomena of liquid atomization affinity by ultrasonic appeared in accordance with liquid loads, namely head h.

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퀜칭한 SCM 440 강에서 초음파 전파특성에 미치는 템퍼링온도의 영향 (The Effect of Tempering Temperature on Ultrasonic Velocity Property at the Quenched SCM 440 Steel)

  • 이계완;김문일;박은수
    • 열처리공학회지
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    • 제4권3호
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    • pp.54-62
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    • 1991
  • The effect of tempering temperature on the ultrasonic propagation velocity at SCM 440 steel quenched from $870^{\circ}C$ and $1000^{\circ}C$ has been studied by metallurgical and crystallographical observation. The measurements of ultrasonic velocity were made on the specimen by appling an immersion ultrasonic pulse-echo technique with a constant frequency of 10 MHz. The quenched microstructure of this steel was a lath martensite. As the tempering temperature was increased, the martensite was transformed into the tempered martensite composed of cementite and carbide. The ultrasonic velocity increased with increasing the tempering temperature. It was thought that these were resulted from the microstructural transformation. The change of ultrasonic propagation velocity with quenching and tempering heat treatment was resulted from microstrain due to the change of internal stress. Considering these results concerning to the change of ultrasonic propagation velocity. the phenomena of microstructural transformation were estimated. Consequently, it was thought that the degree of quenching and tempered heat treatment of steel could be nondestructively evaluated with the change of ultrasonic propagation velocity.

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An Intelligent Nano-positioning Control System Driven by an Ultrasonic Motor

  • Fan, Kuang-Chao;Lai, Zi-Fa
    • International Journal of Precision Engineering and Manufacturing
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    • 제9권3호
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    • pp.40-45
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    • 2008
  • This paper presents a linear positioning system and its control algorithm design with nano accuracy/resolution. The basic linear stage structure is driven by an ultrasonic motor and its displacement feedback is detected by a LDGI (Laser Diffraction Grating Interferometer), which can achieve nanometer resolution. Due to the friction driving property of the ultrasonic motor, the driving situation differs in various ranges along the travel. Experiments have been carried out in order to observe and realize the phenomena of the three main driving modes: AC mode (for mm motion), Gate mode (for ${\mu}m$ motion), and DC mode (for nm motion). A proposed FCMAC (Fuzzy Cerebella Model Articulation Controller) control algorithm is implemented for manipulating and predicting the velocity variation during the motion of each mode respectively. The PCbased integral positioning system is built up with a NI DAQ Device by a BCB (Borland $C^{++}$ Builder) program to accomplish the purpose of an intelligent nanopositioning control.

초음파 속도법을 이용한 콘크리트의 고온열화 평가에 대한 연구 (Study on Evaluation of High Temperature Degradation of Concrete using Ultrasonic Velocity Method)

  • 황의철;김규용;최경철;윤민호;김홍섭;이보경
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2016년도 추계 학술논문 발표대회
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    • pp.146-147
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    • 2016
  • Concrete has been recognized as a material which is resistant to high temperatures, but chemicophysical property of concrete is changed by the high temperature. So, mechanical properties of concrete may be reduced. So, concrete at high temperature is evaluated mechanical properties for safety inspection. However, research of ultrasonic method is not much. Therefore, the purpose of this study is to NDT(non-destructive test) of 30, 70, 110MPa concrete exposed high temperature using ultrasonic pulse velocity.

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초음파법을 이용한 고온가열 콘크리트의 비파괴 평가 (NDT of Concrete Exposed High Temperature Using Ultrasonic Method)

  • 황의철;김규용;최경철;윤민호;김홍섭;이보경
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2016년도 춘계 학술논문 발표대회
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    • pp.24-25
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    • 2016
  • Concrete has been recognized as a material which is resistant to high temperatures, but chemicophysical property of concrete is changed by the high temperature. So, mechanical properties of concrete may be reduced. So, concrete at high temperature is evaluated mechanical properties for safety inspection. However, research of ultrasonic method is not much. Therefore, the purpose of this study is to NDT(non-destructive test) of 30, 70, 110MPa concrete exposed high temperature using ultrasonic pulse velocity and amplitude.

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렌즈 구동을 위한 선형 초음파 전동기 설계 (Design of Linear Ultrasonic Motor for Small tong Actuation)

  • 권태성;이승엽;김수경
    • 정보저장시스템학회:학술대회논문집
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    • 정보저장시스템학회 2005년도 추계학술대회 논문집
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    • pp.190-194
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    • 2005
  • There is a great demand of micro-actuators for mobile information devices such as SFF optical drives and mobile camera phones. However, conventional magnetic coils of electromagnetic motors are a major obstacle for miniaturization because of their complicated structures and large power consumption. In this paper, a linear ultrasonic motor to actuate focusing lens of mobile devices is proposed. The new actuator uses a ring type bimorph piezoelectric material, and $d_{31}$ mode is adopted for applying linear motion. The interaction between inertia force and friction force makes linear motion by high-frequency saw signal input. The saw signal gives steady forces on the one direction by asymmetric inclination property of the signal itself on time domain. A commercial FEM (ANSYS) was used in this investigation for simulating structural analysis, identification of dynamic property, such as resultant displacement and coupled analysis with piezoelectric material. To evaluate the performance of the new design, a prototype was manufactured and experiments were carried out. Experimental results show the actuator motion of 1.52 mm/s at 10 kHz input signal in 5 V.

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초소형 렌즈 구동을 위한 선형 초음파 구동기 설계 (Design of a Linear Ultrasonic Actuator for Small Lens Actuation)

  • 권태성;최요한;이승엽
    • 정보저장시스템학회논문집
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    • 제2권4호
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    • pp.251-256
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    • 2006
  • There is a great demand of micro-actuators for mobile information devices such as SFF optical drives and mobile phone cameras. However, the magnetic coils used in conventional electromagnetic motors are a major obstacle for the miniaturization because of their complicated structures and large power consumption. In this paper, a linear ultrasonic motor to actuate focusing lens of mobile devices is proposed. The new actuator uses a ring type bimorph piezoelectric material, and $d_{31}$ mode is adopted for applying linear motion. The interaction between inertia force and friction force makes linear motion by high-frequency saw signal input. The saw signal gives steady forces on the one direction by asymmetric inclination property of the signal itself on time domain. A commercial FEM(ANSYS) was used in this investigation for simulating structural analysis, identification of dynamic property, such as resultant displacement and coupled analysis with piezoelectric material. To evaluate the performance of the new design, a prototype was manufactured and experiments were carried out. Experimental results show the actuator motion of 5.4 mm/s at 10V saw signal of 41 kHz.

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시뮬레이션을 통한 압전형 초음파 스케일러 개발 및 평가 (Design and Evaluation of Piezoelectric Ultrasonic Scaler Produced by a Simulation)

  • 김철민;이영진;백종후;정영훈;강국진;이정배;이승대
    • 한국전기전자재료학회논문지
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    • 제22권10호
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    • pp.832-836
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    • 2009
  • A piezoelectric ultrasonic scaler, usually used to remove the tartar out of teeth and to amputate the pubis, is a recently popular instrument for dental treatment due to its several merits such as small size, low-electric power, precision and low-cost. It has typically two parts of a tip and vibration system, which is also composed of head, piezoelectric elements and tail-mass. The scaler concentrates its displacement on tip and has commonly a resonance frequency at 25~30 kHz, and in order to improve the performance of the scaler, it is important to standardize the size of the vibration system without tip for high performance because scaler in quality differs according to several tips. In this study, a Finite Element Analysis (FEA) was utilized to optimize the structure of ultrasonic scaler in the vibration system. Consequently, this study revealed that influence of several tips on property were minimized and scaler showed good property at the resonance frequency of 28 kHz.

초음파 속도 모니터링에 의한 모르터의 초기재령 특성 평가 (Assessment of Early-age Properties of Mortar by Monitoring of Ultrasonic Pulse Velocity)

  • 이회근;이광명
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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    • pp.245-250
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    • 2001
  • Ultrasonic pulse velocity(UPV) is a useful tool for examining the property of early-age mortar or concrete. Thus, UPV has been used for a long time to characterize setting and hardening of cementitious materials. In this study, in order to investigate the characteristics of setting for mortar, UPV was measured using automatic monitoring system up to 3 days after casting. Test results show that UPV of high water to binder ratio(w/b) mortar remained constant at the beginning of hydration and then abruptly began to increase. However, UPV of low w/b mortar gradually increase due to setting retard caused by use of superplasticizer. Furthermore, the development of UPV for mortar with fly ash is slower than that of mortar without fly ash. It was concluded that the property change of mortar or concrete, such as setting and hardening can be assessed by monitoring of UPV.

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해남 대흥사 북미륵암 마애여래좌상의 암석기재적 특성과 손상도 평가 (Petrographic Characteristics and Deterioration Evaluation of the Rock-carved Seated Buddha at Bugmireugam Hermitage in Daeheungsa Temple of Haenam, Korea)

  • 조지현;이찬희
    • 자원환경지질
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    • 제52권6호
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    • pp.617-626
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    • 2019
  • 이 연구에서는 해남 대흥사 북미륵암 마애여래좌상을 구성하는 석재의 암석학적 특성과 물성을 진단하였다. 이 마애불상은 미문상화강암에 부조되어 있으며, 전체적인 암상은 장석에 포위된 작은 석영 결정들이 미문상 조직을 이루고 있다. 손상도 진단 및 평가 결과, 흑색변색(8.4%)과 균열지수(6.6)에서 높은 훼손율을 보였고, 초음파 속도는 약간 풍화단계의 풍화도지수(평균 0.18)가 산출되었다. 마애불의 표면에 나타나는 손상은 기존 보호각의 영향으로 판단되고, 물성은 자연암반의 구조적 특성과 균열의 직접적인 영향에 의한 것으로 해석된다.