• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.851-856
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• 2003

This paper proposes a single-mode Lamb-wave generation and detection system using a pulsed laser as a generator and an air-coupled transducer combined with the wavelet transform analysis, as the detector. The laser source with arrayed linear slits was used to generate Lamb-wave which is able to control the wavelength of Lamb-wave to be generated by changing the slits separation. An ari-coupled transducer was used to receive Lamb-wave, which can selectably receive a single mode of leaky Lamb wave by changing the oblique angle of transducer, since the leaky Lamb-wave has unique leaky-angle according to the mode. Also, the received signal was processed by wavelet transform for the analysis in domain of time-frequency. The theoretical dipersion curve and the experimetal result was compared to show good agreement.

• 한국소음진동공학회논문집
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• 제24권2호
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• pp.123-130
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• 2014

An ultrasonic magnetostrictive transducer-based phased-array system for imaging defects in plate structures is newly proposed. In that most ultrasonic phased array systems rely on piezoelectric transducers or electromagnetic acoustic transducers, this system has its own unique feature of employing magnetostrictive transducers. Interest in using a phased array system using magnetostrictive transducers has been recently reported for pipe inspection but no such system has been developed for plate inspection. In this investigation, we aim to propose a phased array system using OL-MPTs (Omnidirectional Lamb wave Magnetostrictive Patch Transducers) for plate inspection. The developed system consists of a multi-channel function generator, power amplifiers, preamplifiers and a data acquisition unit. In the process of its development, each of the units must be checked and in doing so, we suggest types of ultrasonic wave experiments that should be carried out. Finally, the phased system using a transducer array composed of eight OL-MPTs is newly configured and is applied for actual crack detection experiments.

• 한국염색가공학회지
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• 제12권3호
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• pp.207-217
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• 2000

A new, high-efficiency ultrasonic fabric washing machine was developed to be an energy-efficient washing machine and to enhance fabric washing quality in washing processes of the dyeing and finishing process in the textile industry. This system is composed of ultrasonic wave generator, air blowing nozzle, torque motor for fabric tension control, and enclosed washing bath, multi-tube type exchanger, noiseless heater, air cylinder, expander roller, mangle upper and lower rollers, bend bar, dancer, shower spray nozzle, and solenoid valve, and so on. These elements are synergised for fabric washing. One of the very important principles is the low tension fabric running system. For an efficient washing effect, a counter flow system is also adopted. The new system also adopts the dancer and torque motor to control fabric tension and prevent fabric creasing. Shower spray nozzle, counter flow and overflow apparatus, and air-blowing apparatus are adopted to enhance the fabric washing effect. In this study, peach yoryu, exter, and moss crepe fabrics were washed by the general and ultrasonic washing systems under different conditions respectively. The washing efficiency was affected by the fabric running speed and characteristics of fabrics. Size content after washing increased with increasing the fabric running speed. The values in the general washing system were higher than those of the ultrasonic washing system. The changes of conductivity in the ultrasonic and the cooling bath were affected by the running time under the ultrasonic generating. The values of conductivity decreased as the experimental time passed.

• 한국음향학회지
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• 제23권5호
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• pp.353-361
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• 2004

증기발생기 세관에서의 유도초음파 전파 특성에 관한 연구를 수행하였다. 증기 발생기 세관의 분산선도 및 특정 모드에 대응하는 초음파 입사각을 계산하였다. 수신된 유도초음파에 대하여 short time Fourier transform을 이용한 시간-주파수 분석을 통하여 유도초음파 모드를 확인하였다. 실험적으로 유도 초음파가 증기발생기 세관의 곡관 부분을 통과할 때 뚜렷한 모드 변환을 관측할 수 없었다. 유도 초음파를 이용한 증기발생기 세관의 최적 검사 모드를 제안하고 실험에 의하여 이를 확인하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.109-109
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• 2009

This paper represented driving characteristic of a thin-type ultrasonic motor by fabricating and utilizing two kinds of drivers which could generate sinusoidal wave, square wave, respectively. A thin brass plate was used as a cross shaped vibrator and sixteen ceramic plates were attached on upper and bottom side of the brass plate. From the thin stator, elliptical displacements of the four contact tips were obtained. Speed, torque, and current were measured by applying sinusoidal waves through driving equipment such as function generator, power amplifier: to measure characteristic of the motor. As a result, the speed and the torque changed linearly at either driving frequency of 88.6 ~ 87.6[kHz] or voltage of 24~36[V]. Two-drivers which generate sinusoidal waves and square waves were designed respectively, and then were compared through some experiments in order to be put to practical use. In conclusion, the drivers had similar characteristic of speed-torque at similar frequency and voltage. It was able to control the motor linearly by using the driver generating square wave among two-drivers. Besides, it also was possible to make the drivers smaller.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 춘계학술대회 논문요약집
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• pp.160-160
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• 2004

초음파 여기를 이용한 물체 이송 시스템은 최근 급속히 발달하고 있는 광산업이나 반도체 산업에서 기존의 이송 시스템의 단점을 보완하기 위해 개발되었다. 기존의 이송 시스템들은 이송공정이나 검사 공정 등에서 광소자의 표면손상이나 자기장에 의한 반도체 소자의 전자적 배열의 손상이 우려되었다. 하지만 PZT 액츄에이터로 구동되는 초음파 발생장치(Ultrasonic wave generator)에서 발생한 초음파 여기를 이용하여 물체를 이송시킬 경우 이러한 단점은 보완된다.(중략)

• Structural Engineering and Mechanics
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• 제51권6호
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• pp.1047-1065
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• 2014

The article presents the methodology for finding material damping capacity at higher frequency and at relatively lower amplitudes. The Lamb wave dispersion theory and loss less finite element model is used to find the damping capacity of composite materials. The research has been focused on high frequency applications materials. The method was implemented on carbon fiber reinforced polymer (CFRP) and glass fiber reinforced polymer (GFRP) plates. The Lamb waves were generated using ultrasonic pulse generator setup. The hybrid method has been explored in this article and the results have been compared with bandwidth methods available in the literature.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.327-328
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• 2006

Recently, as the infocomindustry is developed, the semiconductor industry as well as the optical industry such as the optical communication and the optical instrument is developed rapidly. The transmission, storage and processing of information has been reaching an limit because amounts of information increase rapidly. The more quickly the optical communication is developed, the more sharply the demand of optical elements increase. The transport and inspection process is time consuming and the error rate is high, because this process are not automated in case of an optical lens. In this paper, the pick-up system that can hold optical elements and be transferred by the ultrasonic transport system is developed. The inspection system that distinguishes between the existence and the nonexistence of a defect is connected easily to pick-up system. The pick-up system separates the optical glass lens by results of the inspection. The automation program is developed by visual c++ programming.

• 한국진공학회지
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• 제22권4호
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• pp.175-180
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• 2013

본 연구에서는 반도체 소자 생산 공정 중 발생하는 오염입자에 의해 실시간 오염입자 측정장치인 In-Situ Particle Monitor(ISPM)의 광학창의 오염을 방지하기 위한 모듈 개발에 관한 연구이다. 개발한 광학창 오염방지 모듈은 실시간으로 측정하는 ISPM 내 광학창 표면에 오염입자가 흡착되는 것을 방지하기 위한 장치로 적합한 초음파 모듈 개발이 성공적 연구의 핵심내용이다. 또한 그 효과를 극대화하기 위한 구조적인 최적화도 필요하지만 초음파 힘의 표면 전달효율 향상 기술도 개발이 필요한 핵심 기술이다. 개발된 광학창 오염방지 모듈이 장착된 ISPM은 양산용 증착공정 장비(BPSG 증착장비) 배기구에 설치되었으며, 공정조건 별 오염방지 모듈의 성능과 더불어 ISPM 측정 효율도 함께 검증하였다.

• 수산해양기술연구
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• 제25권4호
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• pp.200-208
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• 1989

200MHz ZnO변환기를 이용하여 초음파 현미경을 제작하여, 도미비늘을 화상화하고 광학현미경에 의한 사진과 비교하였다. 그 결과 광학적 반사에 의한 표면의 화상과 초음파의 기계적 탄성적 표면하 반사에 의한 화상에는 다소 차이가 있음을 확인하였다(Fig. 13 및 14). 초음파 현미경은 고체재료 또는 생물조직 상(10(12)등 여러 가지 생물연구 등의 응용이 계획되고 있으며, 특히 초음파 의학의 분야는 그 활용이 눈부실 것으로 예측된다. 초음파 현미경의 제작 그 자체보다, 이것을 도구로 하여 여러 가지 학술적, 기술적 성과가 기대되기 때문에 이 분야의 기초연구가 더욱 중요하게 생각되며 첨단산업분야에서도 비파괴검사 초음파 micro spectroscopy(U.M.S)등과 같은 물질의 탄성적 성질을 micro scale로 계측할 수 있는 등, 많은 활용이 있을 것이 예상된다. 또 초음파 현미경의 방법도 여러 가지이며, 이것을 계측수단으로 일반화하는 문제도 연구할 필요가 있다. 앞으로 광학이나 전자장치 등과 함께 급속한 발전이 기대된다.