• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1853-1856
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• 2003

Multi-layer printed circuit board(PCB) is being used widely for the product with relatively complex circuits such as TV, VTR and FAX. With the rapid enlargement of electronic and IT industry, the hole machining technology on multi-layer PCB is increasingly required to improve. Thus, the micro drilling with ultrasonic vibration can be a good method for hole machining. Unlike conventional drilling, ultrasonic vibration applied drilling introduces less wear and fracture of not only tool but also internal surface of workpiece due to little cutting resistance, thus, machinability can be improved. The experiment is conducted through the comparison between the results of conventional drilling and ultrasonic micro drilling as well as among each results by the variation according to not only feed rate of drill but also amplitude and frequency of ultrasonic vibration. The multi-layer PCB consists of 6 layers and ${\Phi}$0.3 diameter drill was used. As a result, it was found that the state of internal surfaces of holes on multiple layer PCBs is improved by the application of ultrasonic vibration.

• Environmental Engineering Research
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• 제21권1호
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• pp.22-28
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• 2016

The aim of this study was to recycle the waste livestock blood as one of the waste biomass by turning proteins, the main constituent of blood, into effective biological resources like amino acid. Ultrasonic technology was applied to solubilize the proteins in the waste livestock blood. And of the multiple ultrasonic frequencies tested, 20 kHz was confirmed to yield the highest solubilization rate. The optimum pretreatment conditions were determined to be 30-min treatment at an ultrasonic irradiation density of 0.5 W/mL, which resulted in a solubilization rate of 96.01%. Also, a gel permeation chromatography (GPC) confirmed that a large amount of proteins were solubilized, and in an experiment where ultrasonic treatment was applied to kill bacteria, death rates of general bacteria and total coliforms were found to be reduced by 99.93% and 100%, respectively. Based on these results, ultrasonic technology was confirmed to be a crucial part of treating and recycling the proteins in waste livestock blood.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제7권4호
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• pp.228-235
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• 2007

The main purpose of this paper is to manage the container property effectively at the container yard by applying the RTLS technology to the field of port logistics. Yet, many kinds of noises happen to be inputted with the distance value(between the reader and the tag) which is to be inputted into the location identification algorithm, which makes the distance value jumped due to the system noise of the ultrasonic sensor module and the measurement noise. The Kalman Filter is widely used to prevent this jump occurrence; the noises are eliminated by using the EKF(Extended Kalman Filter) while considering that the distance information of the ultrasonic sensor is non-linear. Also, the 3D RTLS system at the port container yard suggested in this research is designed not to be interrupted for its ultrasonic transmission by positioning the antenna at the front of each sector of the container where the active tags are installed. We positioned the readers, which function as antennas for location identification, to four places randomly in the absolute coordinate and let the positions of the active tags identified by using the distance data delivered from the active tags. For the location identification algorithm used in this paper, the triangulation measurement that is most used in general is applied and newly reorganized to calculate the position of the container. In the first experiment, we dealt with the error resulting in the angle and the distance of the ultrasonic sensor module, which is the most important in the hardware performance; in the second, we evaluated the performance of the location identification algorithm, which is the most important in the software performance, and tested the noise cancellation effects for the EKF. According to the experiment result, the ultrasonic sensor showed an average of 3 to 5cm error up to $45^{\circ}$ in case of $60^{\circ}$ or more, non-reliable linear distances were obtained. In addition, the evaluation of the algorithm performance showed an average of $4^{\circ}{\sim}5^{\circ}$ error due to the error of the linear distance-this error is negligible for most container location identifications. Lastly, the experiment results of noise cancellation and jump preservation by using the EKF showed that noises were removed in the distance information which was entered from the input of the ultrasonic sensor and as a result, only signal was extracted; thus, jumps were able to be removed and the exact distance information between the ultrasonic sensors could be obtained.

• International Journal of Advanced Culture Technology
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• 제10권1호
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• pp.284-293
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• 2022

After extracting the calcium component from the KR slag and the converter slag using ammonium chloride solution, the extract was reacted with carbon dioxide to synthesize precipitated calcium carbonate (PCC). In order to understand the effect of ultrasonic waves on calcium extraction from slags and calcium carbonate synthesis, the efficiency of calcium carbonate synthesis according to the with or without of ultrasonic waves was analyzed. The synthetic efficiency of PCC was investigated according to various experimental conditions, and the synthesized calcium carbonate was analyzed using XRD and SEM. In both slags, the amount of PCC decreased as the reaction temperature increased. The pH at the end of the experiment capable of synthesizing the maximum PCC in the carbonation reaction was 7 (irradiated with ultrasound) and 8 (irradiated without ultrasound), respectively. Because the pH of the extraction filtrate is different when irradiated with or without ultrasound, the pH was adjusted to 9 by injecting an additive (10 M NaOH) before the carbonation experiment, and then the experiment was performed. When calcium was extracted from KR slag, the crystal phase appeared as calcite regardless of the pH at the end of the experiment. However, when calcium was extracted from the converter slag and the pH was set to 7 at the end of the experiment, the crystal phase of PCC appeared as a mixture of calcite and vaterite.

• 조명전기설비학회논문지
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• 제27권12호
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• pp.38-43
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• 2013

In this paper, the location measurement method for the reliable location data using ultrasonic sensors is proposed for the dimming control of the LED flat lamp. The measurement errors depending on the reflection angle of the object have to be considered to obtain the reliable location data in the ultrasonic sensors. In the experiment, the cause of the measurement errors depending on reflection angle is analyzed and velocity change of ultrasonic wave depending on reflection angle is measured. And the location measurement method depending on velocity change of ultrasonic wave is proposed. From the results, the average absolute deviation of the x-coordinates was 1.47cm when the location measurement method was considered, and it was closer to the true values than the average absolute deviation of the x-coordinates which was 5.89cm without regard to the reflection angle.

• 대한기계학회논문집A
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• 제23권7호
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• pp.1065-1074
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• 1999

This study proposes the analysis and evaluation method of time series ultrasonic signal using the chaotic feature extraction for ultrasonic pattern recognition. Features extracted from time series data using the chaotic time series signal analysis quantitatively welding defects. For this purpose analysis objective in this study is fractal dimension and Lyapunov exponent. Trajectory changes in the strange attractor indicated that even same type of defects carried substantial difference in chaoticity resulting from distance shills such as 0.5 and 1.0 skip distance. Such differences in chaoticity enables the evaluation of unique features of defects in the weld zone. In experiment fractal(correlation) dimension and Lyapunov exponent extracted from 6dB ultrasonic defect signals of weld zone showed chaoticity. In quantitative chaotic feature extraction, feature values(mean values) of 4.2690 and 0.0907 in the case of porosity and 4.2432 and 0.0888 in the case of incomplete penetration were proposed on the basis of fractal dimension and Lyapunov exponent. Proposed chaotic feature extraction in this study enhances ultrasonic pattern recognition results from defect signals of weld zone such as vertical hole.

• 한국생산제조학회지
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• 제24권5호
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• pp.530-534
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• 2015

Ultrasonic nanocrystal surface modification (UNSM) is an example of a nanoscale-surface modification that has become noticeable because of its effects on the mechanical improvement of metallic materials. UNSM equipment needs to be both utilized and improved. The equipment is based on an ultrasonic waveguide whose role is to strike surfaces of metallic materials to achieve nanoscale deformation. In this paper, we introduce the development of one kind of UNSM equipment. Using piezoelectric elements, we repeatedly design and fabricate a 20-kHz ultrasonic waveguide. With respect to the composition of the equipment, the waveguide is automatically transferred by two axial stages automatically. In addition, a static force is constantly applied by pneumatic devices. We perform an experiment to verify the feasibility of the equipment.

• 한국생산제조학회지
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• 제23권4호
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• pp.385-391
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• 2014

A control system for ultrasonic spray pyrolysis deposition was developed that can coat a large size glass panel with a transparent conductive oxide. It consists of several ultrasonic atomizer devices to cover a large area and a host computer for individually controlling the devices. The sub-controller in an ultrasonic atomizer device can adjust the flow rate of the atomized conductive oxide gas by setting the flow rate of the solution and regulating the level of the solution in the tank. To construct a feedback control loop for level regulation, a level sensor that utilized an infrared distance sensor and an electric circuit for adjusting the ultrasonic oscillator were developed. The host program was also developed, which can monitor and control the sub-controllers. A proportional-integral controller was developed for a simplified model, and its operation was verified through an experiment.

• 제어로봇시스템학회논문지
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• 제9권12호
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• pp.1009-1018
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• 2003

In a park or street, we can see many people Jogging or walking with their dogs chasing their masters. In the previous study, an entertainment robot, CARTRI that imitates the dog's behavior was created. The robot's task was chasing a moving goal that was recognized as the master. The physical structure of the CARTRI robot was three-wheel type locomotion system. The sensor system which could detect the position of the master in the outdoor space, was consists of a signal transmitter which was held by the master and five ultrasonic receivers which were mounted on the robot. In the experiment, the robot could chase a human walking in outdoor space like a park. But it could not avoid obstacles and its behavior was only goal-chasing behavior because of the limit of the sensor system. In this study, an improved RF-ultrasonic sensor system which can detect both goal and obstacle is developed in order to enable the CARTRI robot to carry out various behavior. The sensor system has increased angle resolution by using eight ultrasonic receivers instead of five in the previous study. And it can detect obstacle by using reflective type ultrasonic sensors. The sensor system is designed so that detection of goal and obstacle could be conducted in one sampling period. The Performance of the developed sensor system is evaluated through experiments.

• 한국재료학회지
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• 제13권10호
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• pp.651-657
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• 2003

Ultrasonic microscope has been used to detect the defects on surface or inner solid. Conventionally, it has used at a single operating frequency. The resolution and quality of the measured images are determined by a characteristic of the transducer of the ultrasonic microscope. The conventional ultrasonic microscope has been used envelope detector to detect the amplitude of reflected signal, but the changes in amplitude is not sensitive enough for specimen with microstructure that in phase. In this paper, we have studied multi-frequency depth resolution enhancement with ultrasonic reflection microscope for the reflectors of a stainless steel reference specimen and a reference calibration block to be used as the material in nuclear power plants for ISI, PSI. Increased depth resolution can be obtained by taking two, three-dimensional images at more that one frequency and numerically combining the results. As results of the experiment, we could get enhanced images with the rate of contrast in proportion and high quality signal distribution for the image to the changing rate of depth for the reflectors of the two kinds of specimens.