• 전기의세계
• /
• v.25 no.6
• /
• pp.74-80
• /
• 1976

The temperature rise of the mortars while are being irradiated by ultrasonic waves and immersed in a liquid medium, are measured. The mixing ratios of sand to cement are varied for the different mortars. The results of the experiment are as follows, 1. The temperature rise of the mortar is decreased as themixing ration (S/C) is increased. 2. Thd temperature rise of the specimen is increased as its length is increased. 3. The surface conditions, either smooth or rough, may not have much influence on the temperature rise of the mortar. 4. The initial slope of temperature rise may not have much effect of the viscosity of liquid. The results, describes above, appear well coincide with the theory that the temperature rise is attributed mainly to the absorption heating. Since the absorption heating of the mortars varies with the mixing ratios of sand to cement, the strength of them would be estimated by means of irradiation of ultrasonic waves on the specimen.

• Journal of the Korean Society of Physical Medicine
• /
• v.10 no.1
• /
• pp.91-97
• /
• 2015

PURPOSE: In this study investigated the thermal effect in tissue mimicking phantom by the material of the ultrasonic transducer in low intensity sonication. METHODS: The material of the ultrasonic transducer was made of ceramic, stainless steel, aluminum. Korea Testing Laboratory was measured of the three kinds of materials the total output of the ultrasonic transducer. Each material was measured core temperature and the actual output depending on the type of transducer. Agarose tissue mimicking phantom and silicone tissue mimicking phantom was made. Transducers made of three kinds of materials were emitted in the phantom. It is shown as a graph about time and temperature and the surface temperature rising speed and deep temperature rise rate was investigated. RESULTS: Ceramic transducers were highest output. Higher than the stainless steel transducer, aluminum had the lowest total output. Deep temperature was the highest in the ceramic transducer, and the surface temperature was the highest in the stainless steel transducer. Thermal images of ceramic transducer showed that a valid output is formed deeper wider than the metal. CONCLUSION: Ceramic transducer is confirmed the excellence than the metal transducer in deep thermal effect and the actual output of the ultrasound.

• Transactions of the Korean hydrogen and new energy society
• /
• v.13 no.2
• /
• pp.127-134
• /
• 2002

A Study on the application of ultrasonic with high frequency is carried out as a plan to rise the efficiency of the hydrogen fuel production in an electrolysis of water. KOH is selected as an electrolyte and concentrations are 0 %, 10 %, 20 %, and 30%. The solvent is city water. A measurable device of buoyancy by an electronic balance and a measurable device of voltage with a sensor of pressure are planned newly as a measuring device to measure the quantity of hydrogen production. An ultrasonic transducer with high frequency of 2 MHz is selected to give them the ultrasonic forcing. In results, it is clarified that ultrasonic influences the decrease of overpotential in the electrolytic solution. And basic data according to the pole interval and the temperature are obtained.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1999.05a
• /
• pp.403-405
• /
• 1999

Power transformers have a tendency of ultra-high voltage and huge capacity as power demand increases day after day. Therefore, the fault by insulation destruction gives rise to large area of power failure in huge capacity transformers. On-line predictive diagnostics is very important In power transformers because of economic loss and its spreading effect. Hence, this study presents experiments of partial discharge method using ultrasonic sensor in order to confirm the possibility of ultrasonic sensor in power transformers. It carries out the experiments of measuring delay time between ultrasonic sensor and transducer, sensitiities by temperature change of oil and by barriers inside transformers. It is also Included wave analysis by ultrasonic sensor for needle-plate electrode powered on through high-voltage equipments.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
• /
• 2003.10a
• /
• pp.127-132
• /
• 2003

In a today industry, the welding is doing a many portion in structure manufacture. This study is simulated heat of heat-effected zone and researched a mechanical properties and ultrasonic characteristic in used the SS400 and the STS304. As the result mechanical properties of steel that become drawing decreased because of remaining stress by strain gardening according as simulated heat temperature rises, but according as temperature rises in material that do simulated heat after have done annealing, mechanical propensity was improved. The velocity and attenuation become different by effect of remaining stress than effect of material internal microstructure in ultrasonic wave test. In the case of STS304, there was change in mechanical properties by effect that is by strain hardening, but there was no change in material that simulated heat after annealing. When become drawing in ultrasonic waves test, according as simulated heat temperatures rise, change of attenuation coefficient is looked, but material that simulated heat after annealing was no change almost both the volocity and attenuation.

• Proceedings of the KSME Conference
• /
• 2008.11b
• /
• pp.2750-2753
• /
• 2008

This paper introduce the CFD analysis for predicting the heat transfer at the Ultrasonic horn. Approximately Ultrasonic horn separates two part. One is preheating part and the other is cooling part. Temperature of preheating part rise up by $260^{\circ}C$ that make it possible to attach a chip to a semiconductor. Also there is a piezo material in the cooling part. When piezo work, it generates heat of $100^{\circ}C$. It can stand by $150^{\circ}C$. But the high temperature conducted from the preheating part has a bad affect on the piezo. These situation make it necessary cooling at piezo. Previously except of the piezo, all of them are composed of the SUS440c that has good thermal conductivity. This study shows way that not only cooling the piezo but also cutting off the conduction between preheating part and cooling part by using the Ti and Duralumin that have low thermal conductivity compare with the SUS440c. Conclusion of CFD analysis that the heat coming from the piezo can't be transferred the horn cause of the Ti and Duralumin.

• Journal of the Korean Society of Radiology
• /
• v.16 no.6
• /
• pp.751-759
• /
• 2022

Currently, ultrasound examination for diagnostic ultrasound and health examination purposes is widely used, and it is showing an increasing trend due to the application of health insurance. However, the risk of ultrasound has not been clearly identified so far, and in this study, surface and deep temperature changes according to frequency and mode were measured by using a tissue mimicking phantom and TI and MI values were compared. A simulated phantom was manufactured by adding a small amount of kappa-caraginan powder with acoustic characteristics similar to that of the human body and potassium chloride for solidification, and the change of surface and depth temperature was measured using a surface thermometer and a probe thermometer. As a result, the convex probe using low frequency showed a higher temperature increase than the linear probe using high frequency, so there was a significant difference, and the temperature increase was the highest on the surface, and the depth of 1cm showed a temporary temperature increase, but there was no significant temperature change. There was no change in the deep temperature of 5 cm to 15 cm, and the TI and MI values did not change during the test time. Since only the surface temperature rose during the 15-minute test and there was no temperature change in the core, so it is not expected to show a temperature change that is harmful to the human body. However, it is thought that prolonged examination of one area may cause temperature rise, so it should be avoided.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.24 no.11
• /
• pp.2723-2731
• /
• 2000

Ultrasonic motors(USM) has been emerging as one type actuators, which possess many advantages such as high torque, low weight, compact size and no magnetic field generation. In spite of these features, there are several problems to be solved, which are temperature rise in case of long term operation, non -linearity, and hysteresis. Among these, hysteresis cause the most serious problem in force/torque control applications. To cope with this paper we propose a new PWM driving method which can be applied to force/torque control applications. To cope with this problem, in this paper we propose a new PWM driving method which can applied to force/torque control of USM. To verify the proposed method, an experimental setup was built and several experiments were performed.

• The Journal of the Acoustical Society of Korea
• /
• v.23 no.7
• /
• pp.503-513
• /
• 2004

In this paper, the thermal sensitivity, i .e. the temperature rise per unit acoustic power, was newly defined and proposed as a performance parameter of a tissue mimicking material. Eatable tofu (bean curd) manufactured by a factory was selected as a sample material for the experiment. The temperature changes were measured not only with the variation of ultrasonic irradiation time, acoustic power, depth from the sample surface. and the distance from the source transducer while adjusting the frequency to 8 MHz but also with the variation of frequency while acoustic power. depth from the sample surface. and the distance from the source transducer keeping constant. As a result of a consideration for the transformation of the measured temperature changes to thermal sensitivities. the thermal sensitivity was found to be sufficient to use as a Performance parameter for tissue mimicking material. The tofu as a tissue mimicking material showed the maximum thermal sensitivity at 10 MHz, as is a significant result to imply the possibility that the thermal sensitivity of real human tissue strong1y depends on the frequency.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.4
• /
• pp.1511-1517
• /
• 2012

Vacuum chamber or vacuum tube for the exhaust process of vacuum glazing is presently used, where excessive time and expenses are required to make the whole vacuum chamber or tube vacuum. To solve this problem, multifunction equipment for vacuum exhaust and ultrasonic joining at atmospheric pressure has been developed, in which a piezoelectric vibrator experiences excessive temperature rise resulting in optimizing the cooling of the equipment. Therefore, in this study, cooling effects of natural convection and forced convection methods were identified by numerical analysis and experiments, and cooling performance of the multifunction equipment was optimized.