• 한국음향학회지
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• 제29권2호
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• pp.91-96
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• 2010

본 연구에서는 식물의 씨로부터 착유하는 기존의 착유방법에 있어서 착유 효율의 한계를 개선하기 위하여 초음파를 이용한 부가 에너지의 적용 가능성을 실험적으로 확인 하였다.그 결과, 기존의 압착방식에 의한 착유 방식에 란주반형 트랜스듀서로부터 방사되는 초음파 진동에 의한 압력을 부가함으로써 기존의 단순압착 방식의 착유효율이 15 %인 경우 25 %로 증가하여 적지 않은 효율의 증가를 보였다. 초음파에 의한 부가 압력을 해석하기 위하여 착유시료의 음향임피던스 및 초음파 트랜스듀서의 전통속도를 측정하여 방사되는초음파의 음압진폭을 구한 결과 단순압착 정압의 약 2.8 %에 불과했으나 초음파 주기에 따른 양력의 변회는 착유효율증가에 매우 효율적임을 확인할 수 있었다.

• 전력전자학회논문지
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• 제5권2호
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• pp.105-114
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• 2000

본 논문에서는 진행파형 초음파 모터 구동을 위한 직렬형 모터측에 직렬로 삽입되는 인덕터의 설계를 위한 새로운 해석 방법을 제시하였다. 초음파 모터의 구조를 등가적으로 해석하였고 이를 토대로 직렬 인덕터의 선정법을 제시하였다. 직렬 인덕터가 최적으로 설계되었을 때 모터 내부의 기계측 고유 공진 요소에 효율적인 전력이 전달될 수 있음을 시뮬레이션을 통하여 확인하였다. 여러 단계의 외부 인덕터에 대한 실험을 통하여 초음파 모터의 주파수 및 속도 특성이 검토되었다. 그 결과 제안된 외부 인덕터 선정방법의 타당성이 입증되었다.

• 한국구조물진단유지관리공학회 논문집
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• 제8권4호
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• pp.123-133
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• 2004

레일 용접부에 존재하는 각종 결함을 검출하고 이에 대해 정량적으로 평가하는 것은 구조물 전체의 건전성 및 안정성 측면에서 대단히 중요하다. 현재 용접부 내부 결함 검색을 위하여 널리 사용되고 있는 초음파 검사법은 국내 및 국외의 경우 아직 레일에 대한 뚜렷한 평가기준이 제시되어 있지 않은 상태이다. 따라서 현장에서는 탐상기를 보유하고 있어도 이를 정확하게 사용하지 못하고 탐상 결과에 대해서도 합부를 판단하지 못하는 실무자들이 대부분이다. 이에 본고에서는 실무에 있어 현장 기술자들이 알아야 할 레일 용접부의 초음파 탐상에 대하여 첫째, 현재 발주처별 적용하고 있는 국내 궤도 공사 시방서의 문제점 및 개선방향 둘째, 철도 레일 용접부의 초음파 탐상 시험의 적용 방법에 대하여 논하고자 한다.

• 대한방사선기술학회지:방사선기술과학
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• 제41권3호
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• pp.241-247
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• 2018

The purpose of this study was to compare the ultrasound gel container washing methods for the sterilization of contaminants and to find the useful methods for the prevention of infection caused by the ultrasonic gel containers. In this experiment, a 250 mL ultrasonic gel container was used, and the ultrasonic gel used was a non-sterile gel (ECO GEL 99, SeungWon Medical, Korea). In order to evaluate the degree of contamination, new 250 mL 15 containers were divided into 5 groups to perform five types of washing by no treatment, washing with water, washing with soap, washing with bottle cleaner and high disinfection level washing. After the washing process, filled the gel container with gel and after 2 weeks, the number of colonies in the gel container was sampled repeatedly twice in the same ultrasonic laboratory and compared before and after washing. As a result of among the five cleaning methods used in this study, 87.2% and 88.9% of the soapy water washing (p = 0.028) and high level washing (p = 0.027) showed significant bacterial reduction rates, respectively. Our findings conclusively an ultrasonic gel container cleaning method for removing contaminants has been found to be an effective sterilization method at a low cost with a soapy water cleaning method. Therefore, it is expected that it will be helpful to prevent the infection caused by the ultrasonic gel container by suggesting the sterilization cleaning method that is practically useful in this study.

• 한국정밀공학회지
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• 제4권1호
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• pp.65-73
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• 1987

In recent days, the application of ultrasonics has been increased in the field of engineering and medicine. The ultrasonic hardness tester to apply the principle of contact compliance method is entirely different from hardness tester in the past and in the practical use, the more pre- cisive measurement is required because it has a slight change of hardness value due to the difference of resonance frequency. Therefore, in this study, as one type of applicative transducers which can detect the optimum pressure load, ring type load cell was used in the measurement of ultrasonic hardness. From experimental results, it was compared ultrasonic hardness testing method with the other hardness testing methods. Also, the measurement error of ultrasonic hardness tester could be measured within .+-. 0.5 HRC F.S. in the case of 3.0Kg pressure load.

• 비파괴검사학회지
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• 제23권6호
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• pp.577-582
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• 2003

This paper describes a new technique for thickness measurement of a very thin layer less than one-quarter of the wavelength of ultrasonic wave used in the ultrasonic pulse-echo measurements. The technique determines the thickness of a thin layer in a tapered medium from constructive interference of multiple reflection waves. The interference characteristics are derived and investigated in theoretical and experimental approaches. Modified total reflection wave g(t) defined as difference between total and first reflection waves increases in amplitude as the interfacial layer thickness decreases down to zero. A layer thickness less than one-tenth of the ultrasonic wavelength is measured using the maximum amplitude of g(t) with a good accuracy and sensitivity. The method also requires no inversion process to extract the thickness information from the waveforms of reflected waves, so that it makes possible to have the on-line thickness measurement of a thin layer such as a lubricating oil film in thrust bearings and journal bearings during manufacturing process.

• Journal of Biosystems Engineering
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• 제21권4호
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• pp.467-473
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• 1996

Ultrasonic energy was applied for atomizing rice-bran oil which is a highly viscous bio fuel. Six different nozzles, an injection simulator, and an ultrasonic generator system were designed and constructed for the experiment. An immersion liquid method was used for the measurement of injection droplet sizes. The characteristics of injection droplets was investigated with respect to the numbers of the droplets with diameters ranging from 5$\mu$m 50$\mu$m and to the Sauter mean diameter. The results showed that the ultrasonic energy was effective for the improvement of the atomization of the injection droplets for all the factors such as type of nozzles, nozzle opening pressures, and collection distances.

• 비파괴검사학회지
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• 제28권3호
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• pp.263-272
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• 2008

Many technical methods are used for nondestructive testing field for solid materials. Among those, ultrasonic inspection methods are widely used and one of the popular methods involves the extraction of an appropriate set of features followed by the use of a neural network for the classification of the signals in the feature space. This paper describes an approach which uses LMS method to determine the coordinates of the ultrasonic probe followed by the use of SAFT with centroid technique to estimate the location of the ultrasonic reflector. The method is employed for classifying UT-NDE signals from the steam generator tubes in a nuclear power plant. The classification results are presented for the ultrasonic signals from cracks and deposits within steam generator tubes.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권6호
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• pp.450-456
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• 2000

In this paper, we proposed a novel control method which uses the internal impedance angles as a control parameter to drive traveling wave type ultrasonic motor. An impedance characteristic of the ultrasonic motor is obtained by analysis of the equivalent circuits including the external inductor used to generate the coupled resonance. The phase angle of internal impedance to achieve optimal control performance is derived. For the tracking of impedance angle, an information of phase difference is obtained from the applied voltage and current. The high speed phase difference detector is designed to monitor the phases of ultrasonic motor. The effectiveness of the proposed control scheme is clarified by experiments.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.287-288
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• 2008

에폭시-층상실리케이트 나노콤포지트의 균질분산과 층상실리케이트내로 침투되는 박리정도를 향상시키기 위해 친환경적 분산기법인 물리적방법으로 Homogenizer와 Power Ultrasonic를 적용한 기법을 실시하였다. Homogenizer의 최적속도를 얻기 위해 분산시킨 나노콤포지트의 박리정도, 유리천이온도를 구할 수 있었고, Homogenizer와 Ultrasonic을 동시에 적용하여 최적시간을 구하기 위해 적용된 나노콤포지트를 절연파괴 강도의 Weibull Plots을 통하여 판단할 수 있는 좋은 결과를 얻을 수 있었다.