• Journal of Periodontal and Implant Science
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• v.30 no.2
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• pp.443-455
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• 2000

The aim of periodontal therapy is a removal of a bacterial plaque butthe instrumentation for plaque control has two nature : removal of a bacterial plaque and increase of surface roughness. Complication of instrumentation is enable to damage to the root surface and artificial crown. Therefore this study was conducted to evaluate the effects of repeated instrumentation on the marginal portion of artificial crown. Fifteen proximal surfaces of ten extracted periodontally diseased maxillary first molars were used. The finish line was placed on the root surface, and then the crown was casted and cemented in usual manner. Three kinds of instruments: hand curet, ultrasonic scaler, and ultrasonic curet were used. After instrumentation, final polishing was done with rubber cup and pumice. And surface changes were evaluated by stereomicroscope and scannig probe microscope. Roughness was increased after instrumentation in all groups, and was decreased after polishing except ultrasonic scaler group. Roughness in the ultrasonic scaler group was lower than others, and roughness after polishing in the hand curet group was lower than others. These results indicate that polishing procedure is recommended, because periodontalinstruments increase the surface roughness and induce the irreversible damage to the marginal portion.

• Journal of the Korean Institute of Telematics and Electronics
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• v.8 no.6
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• pp.1-7
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• 1971

This paper describes concerning the method of measurement for the intensity of ultrasonics in liquid. The probe which is added two sensive point of thermocople which is surrounded by the absorbed material of sonic wave on the both side of the refleftite plate have measured the intensity of ultrasonics indirectly by the difference of the temperature of two sensive point which had raised the temperature by the sonic wave and its reflective wave which transmitted the ultrasonic energy. This minify the influence from the temparature of liquid and time constant. Consequently, this is the basic industrial method which is with in the bounds of possibility on the simple measurement of the intensity of the local ultrasonics concerning direction of its propagation.

• The Journal of Korea Robotics Society
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• v.12 no.4
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• pp.395-401
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• 2017

In this paper, we introduce a robot-assisted medical diagnostic system that enables remote ultrasound (US) imaging to be applied to the conventional telemedicine, which has been possible only with interviewing or a visual exam. In particular, a master-slave robot system is developed that ultrasonic diagnosis specialist can control the position and orientation of US probe in the remote place. The slave robot is designed to be compact, lightweight, and hand-held so that it can easily transfer to the remote healthcare center. Moreover, 6-degree-of-freedom (DOF) probe motion is possible by the robot design based on Stewart platform. The master device is also based on a similar structure of the slave robot. To connect master and slave system in the wide area network (WAN) environment, a hardware CODEC was developed. In this paper, we introduce the detail of each component and the results of the recent experiments conducted in the remote sites by the developed robotic ultrasound imaging system.

• Journal of the Korean Chemical Society
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• v.34 no.6
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• pp.555-560
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• 1990

High temperature superconducting films of $YBa_2Cu_3O_{7-x}$ were fabricated on the (100) single crystal faces of YSZ (yttria stabilized zirconia) and SrTi$O_3$ by aerosol spray using ultrasonic atomization. The superconducting phase was formed by a three-step process: (a) spraying of a stoichiometric solution of nitrates of yttrium, barium, and copper on heated substrates kept at 250$^{\circ}C$, (b) preheating of the sprayed films in air at 550$^{\circ}C$, and (e) sintering of the films in flowing oxygen at 950$^{\circ}C$, followed by furnace cooling. Resistances of the films were measured by the dc four-probe method and superconductivity was confirmed above the liquid nitrogen temperature.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.10
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• pp.828-834
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• 2001

Zinc oxide (ZnO) films deposited on indium (In) films were post-annealed in a rapid thermal anealing (RTA) system. The ZnO/In films were RTA-treated in air or a vacuum ambient. The crystallographic properties and surface morphologies of the films were studied before and after the RTA by X-ray diffraction(XRD) and scanning electron microscopy (SEM), respectively. The resistivity variation of the films with RTA temperature and time was measured by the 4-point probe method. Auger electron spectroscopy (AES) was carried out to figure out the redistribution of indium atoms in the ZnO films. The resistivity of the ZnO/In films decreased to 2$\times$10$\^$-3/ Ωcm by diffusion of the In. The In diffusion into the ZnO films roughened the surface of ZnO films. The results of depth profile by AES showed a hump of In atoms around ZnO/In interface after the RTA at 800 $\^{C}$. The effects of temperature time and ambient during the RTA on the structural and electrical properties of the ZnO/In films were discussed.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.6
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• pp.738-744
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• 2011

The reliability of blade root fixing section is required to endure the centrifugal force and vibration stress for the last stage blade of steam turbine in thermal power plant. Most of the domestic steam turbine last stage blades have finger type roots. The finger type blade is very complex, so the inspection had been performed only on the exposed fixing pin cross-section area due to the difficulty of inspection. But the centrifugal force and vibration stress are also applied at the blade root finger and the crack generates, so the inspection method for finger section is necessary. For the inspection of root finger, inspection points were decided by simulating ultra-sonic path with 3D modeling, curve-shape probe and fixing jig were invented, and the characteristics analysis method of ultrasonic reflection signal and defect signal disposition method were invented. This invented method was actually executed at site and prevented the blade liberation failure by detecting the cracks at the fingers. Also, the same type blades of the other turbines were inspected periodically and the reliability of the turbine increased.

• Journal of the Korean Society of Radiology
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• v.17 no.6
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• pp.957-964
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• 2023

This study focused on hand sanitizer as a medium that can replace ultrasonic gel, which is vulnerable to contamination by bacteria that reside on the hand. Hand sanitizer produces a strong sterilization effect from germs resident on the hands through different sterilization principles depending on the ingredients. Select products of gel type, cream type, and foam type, except for liquid type with low viscosity, and ultrasonically apply one 62% ethanol gel type and one cream type, one benzalkonium chloride 0.066% cream type and one foam type, respectively. Using ATS-539 as a medium, image evaluation was performed on the axial and lateral resolution and penetration depth, and the presence or absence of an air layer between the probe and the phantom. As a result, in the evaluation of the axial and lateral resolution and the depth of penetration, all four experimental groups met the evaluation criteria. However, in the case of the foam type, although it was suitable for the evaluation criteria of resolution and penetration depth, dark shadows appeared on both sides except for the center of observation during image evaluation. Through this experiment, it was possible to confirm the possibility that the remaining three types of hand sanitizers except the foam type could replace the ultrasonic gel.

• International Journal of Aeronautical and Space Sciences
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• v.4 no.1
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• pp.63-74
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• 2003

The vortical flow of a 65-deg flat plate delta wing with a leading edge extension(LEX) was examined through off-surface visualization, 5-hole probe and hot-film measurements. The off-surface flow visualization technique used micro water droplets generated by a home-style ultrasonic humidifier and a laser beam sheet. The angles of attack ranged from 10 to 30 degrees, and the sideslip angles ranged from 0 to -15 degrees. The Reynolds number was $1.82{\times}10^5$ for the flow visualization, and $1.76{\times}10^6$ for the 5-hole probe and hot-film measurements. The comparison of the visualization photos and the flow field measurement showed that the two results were in a good agreement for the relative position and the structure of the wing and LEX vortices, even though the flow Reynolds numbers of the two results were much different. The wing vortex and the LEX vortex coil each other while maintaining a comparable strength and identity at zero sideslip. Neither a looping of the wing vortex around the strake vortex, nor the lopsided coiling of the stronger strake and the weaker wing vortices was observed. At non-zero sideslip, the downward movement of the LEX vortex when going downstream was enhanced on the windward side, and the downward and inboard movement of the LEX vortex when going downstream was suppressed on the leeward side. The counterclockwise coiling of the wing and LEX vortices was decreased significantly on the leeward side.

• Journal of the Korea Convergence Society
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• v.9 no.4
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• pp.143-150
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• 2018

This work conducted the experimental analysis on ultrasonic acoustic matching in order to measure the accuracy of gaseous fuel level values. The experimental devices were used as 12V-DC supply, control T1 board, oscilloscope (DS01072B), ultrasonic probe and pattern table. The research models were designed by ceramic assay which can determine the transmitting and receiving energies. The result of the ringing area could verify the increased characteristics in the order of D (0.180m) < E (0.184m) < B (0.204m) < A (0.234m) < F (0.244m) < C (0.247m) models based on initial 2.9V of the maximum peak voltage. From the experimental results, the model designed by Ø21*3+2t of the matching layer was notable in that the most outstanding directivity energy could be created.

• Particle and aerosol research
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• v.9 no.4
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• pp.231-238
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• 2013

Carbon nanotubes (CNTs) are one of the nanomaterials that were discovered by Iijima in 1991 for the first time. CNTs have long cylindrical and axi-symmetric structures. CNTs are made by rolling graphene sheets. Because of their large length-to-diameter ratio, they are called nanotubes. CNTs are categorized as single-walled carbon nanotubes (SWCNTs) or multi-walled carbon nanotubes (MWCNTs) based on the shell structures. CNTs are broadly used in various fields, such as scanning probe microscopy, ultra fine nano balance and medicine, due to their extraordinary thermal conductivity, electrical and mechanical properties. Because long, straight CNTs have the same shape as asbestos, which cause cancer in cells lining the lung, there have been many studies on the effects of MWCNTs on human health that have been conducted. Stable atomization of CNTs is very important for the estimation of inhalation toxicity. In the present study, electro-static assisted axial atomizer (EAAA), which is the instrument that uses MWCNTs and aerosolizes them by transforming the single fiber shape using ultrasonic dispersion and electric field, was invented. EAAA consists of a ultrasonic bath for dispersion of MWCNTs and a particle generator for atomizing single fibers. The performance evaluation was conducted in order to assess the possibilities of 6-hour straight atomization with stability, which is the suggested exposure time in a day for the estimation of inhalation toxicity.