• The Journal of the Acoustical Society of Korea
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• v.9 no.2
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• pp.25-33
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• 1990

An ultrasonic power measurement system in milliwatt range was constructed. The ultrasonic power can be determined by measuring the radiation pressure on a target using self-compensating microbalance. Measurement was performed using a perfect reflector and a perfect absorber. In order to check the feasibility of the system, the ultrasonic power for the two targets was measured. Also, the systematic measurement errors and the reproducibility were examined. The relative error between two targets is proved to be within 2%. Also when the ultrasonic power range is larger than 10mW, the standard deviation for repeated measurement becomes smaller than ${\pm}$2%.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.5
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• pp.47-52
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• 2011

We studied about the damaged tire decision algorithm that measured dominant period of ultrasonic signal due to a foreign material on the friction between tire and road surface. We computed the power spectrum about the envelope of ultrasonic signal acquired from the damaged tire, then proposed the dominant period decision algorithm by statistical power threshold value. As the result of simulation, when driving by the speed of 80km/h, the 100ms of dominant period that measured in the proposed algorithm is more accurate than the 97.6ms of power spectrum peak period referenced on the average period of ultrasonic signal envelope peak, 101.24ms.

• Journal of Periodontal and Implant Science
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• v.39 no.2
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• pp.139-148
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• 2009

Purpose: Ultrasonic scalers have been widely used for removing biofilm which is considered as major etiologic factor of periodontal disease. The purpose of this study was to evaluate the effect of working parameters of piezoeletric ultrasonic scaler with scaler tip (No. 1 tip) on casting gold alloy removal. Methods: Type III dental casting gold alloy (Firmilay$^{circledR}$, Jelenko Inc, CA, USA) was used as substitute for tooth substance. Piezoeletric ultrasonic scaler and No.1 scaler tip (P-Max$^{circledR}$, Satelec, France) were selected. The selected working parameters were mode (P mode, S mode), power setting (2, 4, 8) and lateral force (0.5 N, 1.0 N, 2.0 N). The effect of working parameters was evaluated in terms of ablation depth, ablation width and ablation area. Results: Mode influenced ablation depth and ablation area. Power also influenced ablation depth and ablation area. Especially, Power 2 and power 8 showed statistically significant difference. Lateral force had influence on ablation width, and 0.5 N resulted significant increase compared with 1.0 N and 2.0 N. Ablation depth was influenced by mode, power and lateral force and defect width was influenced by lateral force. Ablation area was influenced by mode and power. Conclusions: It can be concluded that the use of piezoelectric ultrasonic scaler with No. 1 scaler tip in S mode and high power may result in significant loss of tooth substance.

• Restorative Dentistry and Endodontics
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• v.39 no.4
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• pp.276-281
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• 2014

Objectives: The purpose of this study was to compare the cutting efficiency of a newly developed microprojection tip and a diamond-coated tip under two different engine powers. Materials and Methods: The apical 3 mm of each root was resected, and root-end preparation was performed with upward and downward pressure using one of the ultrasonic tips, KIS-1D (Obtura Spartan) or JT-5B (B&L Biotech Ltd.). The ultrasonic engine was set to power-1 or -4. Forty teeth were randomly divided into four groups: K1 (KIS-1D / Power-1), J1 (JT-5B / Power-1), K4 (KIS-1D / Power-4), and J4 (JT-5B / Power-4). The total time required for root-end preparation was recorded. All teeth were resected and the apical parts were evaluated for the number and length of cracks using a confocal scanning micrscope. The size of the root-end cavity and the width of the remaining dentin were recorded. The data were statistically analyzed using two-way analysis of variance and a Mann-Whitney test. Results: There was no significant difference in the time required between the instrument groups, but the power-4 groups showed reduced preparation time for both instrument groups (p < 0.05). The K4 and J4 groups with a power-4 showed a significantly higher crack formation and a longer crack irrespective of the instruments. There was no significant difference in the remaining dentin thickness or any of the parameters after preparation. Conclusions: Ultrasonic tips with microprojections would be an option to substitute for the conventional ultrasonic tips with a diamond coating with the same clinical efficiency.

• 제어로봇시스템학회:학술대회논문집
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• 1995.10a
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• pp.87-90
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• 1995

When the ultrasonic transducer operating at l MHz for use in cleaning semiconductor wafers or other industsrial materials is driven from the MOS-FET DC-to RF inverter, the output power severely depends on the frequency of operation since the quality factor of the transducer is high. In order to tune to the eresonating frequency of the ultrasonic transducer, the drive signal frequency of the MOS-FET power inverter is automatically scananed until the frequency is set at the resonating frequency of the ultrasonic transducer is maximized. The control circuit consists of an output power sensing circuit, a PLL controller, a frequency standard, and other peripheral circuits. The operation was satisfactory when the transducer having an output of 600 W at 1 MHz was used.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.9
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• pp.1572-1578
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• 2008

The effect of the organoclay_10A nanoparticles on the DSC and Structural and Dielectrics Properties(1Hz-1MHz) for epoxy/Organoclay_10A Nanocomposites has been studied. Dielectric properties of epoxy-Organoclay nanocomposites were investigated at 1, 3, 5, 7, 9 filler concentration by weight. Epoxy nanocomposites samples were prepared with good dispersion of layered silicate using power ultrasonic method in the particles. As structural analysis, the interlayer spacing have decreased with filled nanoparticles contents increase using power ultrasonic dispersion. The maximum increase interlayered spacing was observed to decease for above 5wt% clay loading. The other hand, as decrease with concentration filler of the layered silicate were increased dispersion degree of nanoparticles in the matrix. The interesting dielectric properties for epoxy based nanocomposites systems are attributed to the large volume fraction of interfacesin the bulk of the material and the ensuring interactions between the charged nanoparticle surface and the epoxy chains.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.12
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• pp.1079-1083
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• 1998

In this study, ultrasonic power of Aluminum wire bonder, bond time and bond force are investigated and valued in order to minimize failure of bonding pad lift. We also tried to control those 3 factors properly. We got the conclusion that if we turn down the ability of ultrasonic power or bond time, we can get a pad lift from a boundary between bond pad ad wire because pad metal and wire joining is unstable, but it is best condition when it ultrasonic power is 100∼130unit, bond time is 15∼20msec and bond force is 4∼6gf.

• Journal of the Korean Society for Nondestructive Testing
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• v.24 no.4
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• pp.325-330
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• 2004

Several kinds of low voltage cables have been used in nuclear power plants for the supply of electric power, supervision, and the propagation of control signals. These low voltage tables must be inspected for safe and stable operation of nuclear power plants. In particular, the degradation diagnosis to estimate the integrity of low voltage rabies has recently been emphasized according to the long use of nuclear power plants. In order to evaluate their degradation, the surrounding temperature, hardness of insulation material, elongation at breaking point (EAB), etc. have been used. However, the measurement of temperature or hardness is not useful because of the absence of quantitative criteria; the inspection of a sample requires turning off of the power plant power; and, the electrical inspection method is not sufficiently sensitive from the initial through the middle stage of degradation. In this research, based on the theory that the ultrasonic velocity changes with relation to the degradation of the material, we measured the ultrasonic velocity as low voltage cables were degraded. To this end, an ultrasonic degradation diagnosis device was developed and used to measure the ultrasonic velocity with the clothing on the cable, and it was confirmed that the ultrasonic velocity changes according to the degradation of low voltage cables. The low voltage cables used in nuclear power plants were degraded at an accelerated rate, and EAB was measured in a tensile test conducted after the measurement of ultrasonic velocity. With the increasing degradation degree, the ultrasonic velocity decreased, whose potential as a useful parameter for the quantitative degradation evaluation was thus confirmed.

• The Journal of the Acoustical Society of Korea
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• v.29 no.6
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• pp.355-364
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• 2010

Considering biological safety, it is very important to measure acoustic power from ultrasonic array probe for diagnostic ultrasound imaging applications. In this paper, to measure acoustic power from each element on array probe for ultrasonic diagnostic equipment, we reconstruct and automate the acoustic power measurement system. The acoustic power from linear, phased and curved array were measured and analyzed. As a result of measurement, the effects caused by directivity of sound beam from curved array were founded. To remove these effects, we developed and applied the correction model. The proposed system is useful to evaluate characteristics of the acoustical output power of array probe.

• Journal of Korean Society of Water and Wastewater
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• v.17 no.4
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• pp.567-573
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• 2003

The pretreatment process was carried out to solubilize the sewage sludge for enhancing its biodegradability using alkaline treatment, ultrasonic treatment(15kHz), ozone treatment and different combination of these three methods: alkaline followed by ultrasonic as well as ozone, and ultrasonic followed by alkaline. The solubilization efficiency was evaluated based on the SCOD/TCOD ratio and VSS/TS ratio. In results, the proper condition of alkaline treatment was shown as 30meq/l of NaOH, pH 12 and 3hours of reaction time. Solubilization efficiency increased to 17% from initial 2% based on SCOD/TCOD ratio under this condition. In ultrasonic treatment, the higher ultrasonic power, the longer treatment time and the lower sludge volume resulted in higher solubilization respectively. There was a rapid increase in solubilization efficiency after 20 minute, then it was measured as 32% of SCOD/TCOD ratio in 1 hour at a ultrasonic power of 1,300W with 1/sludge. Solubilization efficiencies in combined treatment using alkaline and ultrasonic were 47-53% higher than single treatment at a sonicated time of 1 hour. Ozone treatment followed by alkaline treatment also represented the enhanced solubilization compared to ozone treatment. Therefore, ultrasonic or ozone treatment assisted by alkaline could achieve the short treatment time as well as high solubilizetion efficiency.