• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.3
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• pp.294-301
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• 2015

Oil filters for vehicular parts are used under high and low temperatures as the engine is cooled, and defects can be generated with repeated changes in the operating environment and with changes in the shape, such as very high internal losses for the bolts. Visually checking for defects inside a bolt is impossible. Nondestructive evaluation methods such as eddy current testing (ECT) are recommended as a more effective way to examine inside a bolt and detect surface defects in a short amount of time. In this study, the fit bobbin coil eddy current probe was applied to checking the bolts. The bolt parameters were calculated by using a COMSOL analysis program to obtain parameters for professional interior design and fault diagnosis.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1109-1117
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• 2011

All objects emit infrared above absolute temperature 0K. Infrared thermography is one of the nondestructive testing technologies to measure the temperature of the object. Infrared thermography shows infrared image which in a longer wavelength than visible light. Infrared technology can be employed regardless of the type or state of the objects. Thus, infrared thermography technique has been used in a wide variety of manufacturing processes in areas such as mechanical, electrical, chemical and medical applications. The advancement of using infrared technology has been increasing. In this paper, the principle of lock-in infrared thermography and its applications were investigated, and the direction of future development was discussed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.6
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• pp.451-456
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• 1990

Underwater acoustic navigation and position fixing systems have been extensively used not only in surface position fixing but also in underwater position fixing. Tn recently, application of these systems has been in the field of underwater inspection of offshore platforms, where it is vital to track the position of an unmanned submersible or diver carrying underwater cameras and nondestructive testing equipment. But these systems are included the fixing errors as results of a signal with additive noise, the attenuation of sound and the interference effects due to multipath reflection and forward scattering. In this paper to improve the position fixing by the supershort baseline acoustic position system, a method to apply the Kalman filter to the fix of the system is proposed and the digital simulation under noise condition is conducted. The optimal positions by the Kalman filter are compared with original positions, and it is confirmed that the results of the pro-posed method are evidently more accurate.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.6
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• pp.9-18
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• 2000

This study includes noise automatic inspection system for washing machine auto-transmission one of modern home necessary. We effort to find and certificate sound noise source by sound power and sound intensity, and apply to frequency analysis in vibration related sound noise. still more we have been studying to data acquisition and programming for MS VisualBasic version 5.0. System component is below. 1) Pentium PC or data acquisition. 2) DSO for noise acquisition. 3)S/W for comparison and decision. 4) I/F Board for data communication. Wave form data through the DSO are converting to ASCII code data. The ASCII code through binary converting S/W. Finally we will making noise monitoring system and automatic inspection system.

• Progress in Medical Physics
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• v.33 no.2
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• pp.11-24
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• 2022

X-ray detection has widely been applied in medical diagnostics, security screening, nondestructive testing in the industry, etc. Medical X-ray imaging procedures require digital flat detectors operating with low doses to reduce radiation health risks. Recently, metal halide perovskites (MHPs) have shown great potential in high-performance X-ray detection because of their attractive properties, such as strong X-ray absorption, high mobility-lifetime product, tunable bandgap, low-temperature fabrication, near-unity photoluminescence quantum yields, and fast photoresponse. In this paper, we review and introduce the development status of new perovskite X-ray detectors and imaging, which have emerged as a new promising high-sensitivity X-ray detection technology. We discuss the latest progress and future perspective of MHP-based X-ray detection in medical imaging. Finally, we compare the conventional detection methods with quantum-enhanced detection, pointing out the challenges and perspectives for future research directions toward perovskite-based X-ray applications.

• Journal of the Korean Society for Nondestructive Testing
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• v.18 no.5
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• pp.389-397
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• 1998

For an effective and efficient management of large amounts of preservice/inservice inspection(PSI/ISI) data in nuclear power plants, an intellegent Windows 95-based data management program was developed. This program enables the prompt extraction of previously conducted PSI/ISI conditions and results so that the time-consuming data management, painstaking data processing and analysis in the past are avoided. The program extracts, and the associated remedies. Furthermore, additional inspection data and comments can be easily added or deleted for subsequent PSI/ISI operation. Although the initial version of the program was applied to Kori nuclear power plant, this program can be equally applied to other nuclear power plant. And also this program can be used to offer the fundamental data for application of evaluation data related to fracture mechanics analysis(FMA), probabilistic reliability assessment(PRA) of PSI/ISI results, performance demonstration initiative(PDI) and risk-informed ISI based on probability of detection(POD) information of ultrasonic examination. Besides, the program can be further developed as a unique PSI/ISI data management expert system that can be apart of PSI/ISI data management expert system that can be a part of PSI/ISI Total Support System(TSS) for Korean nuclear power plants.

• Journal of the Korean Society for Nondestructive Testing
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• v.34 no.2
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• pp.165-170
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• 2014

Shear horizontal (SH) waves propagate as a type of plate wave in a thin sheet. The dispersion characteristics of SH waves can be used for signal analysis. Therefore, SH-waves are useful for monitoring the structural health of a thin-sheet-structure. An electromagnetic acoustic transducer (EMAT), which is a non-contact ultrasonic transducer, can generate SH-waves easily by varying the shape and array of magnets and coils. Therefore, an EMAT can be applied to an automated ultrasonic testing system for structural health monitoring. When used as a sensor, however, the EMAT has a weakness in that electromagnetic interference (EMI) noise can occur easily in the automated system because of motors and electric devices. Alternatively, a fiber optic sensor works well in the same environment with EMI noise because it uses a light signal instead of an electric signal. In this paper, a fiber Fabry-P$\acute{e}$rot interferometer (FFPI) was proposed as a sensor to receive the SH-waves generated by an EMAT. A simple test was performed to verify the performance of the FFPI sensor. It is thus shown that the FFPI can receive SH-wave signals clearly.

• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.4
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• pp.410-417
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• 2012

Currently domestic thermal and nuclear power plants are comprised of many type's condenser and steam generator tubes to produce the electricity of good quality. There are some methods to inspect these tubes in the event that several defects were discovered in these facilities. Among many non-destructive methods, we used guided wave to inspect the soundness of tubes, because this method is very fast to detect the defect and very simple to install the equipment and also, can inspect up to the long range at a fixed point. Also, this method has a drawback that does not detect a very small size defect. So, we made an effort to overcome this drawback through the experimentation and signal analysis according to the size and shape of the defect through the manufacture of various artificial cracks capable to generate within the small size tube in the study and we anticipate that these detect limits can be overcome along with the development of the signal processing and manufacturing technology of the sensor for the inspection.

• Journal of the Korean Society for Nondestructive Testing
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• v.19 no.2
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• pp.93-99
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• 1999

SCAI(spent CANDU fuel bundle serial number identifier) was developed to read serial numbers of spent fuel bundles in the spent fuel storage. For the purpose of effectively identifying the serial number of fuel bundle. SCAI was composed of underwater camera & light part. guiding & supporting part and control & monitor part. So it is easy to assemble and disassemble, and operate. It was tested to read serial numbers of spent fuel bundles loaded in basket during the recent spent fuel transfer campaign at Wolsong Unit 1. And it was also applied to read serial numbers of spent fuel bundles discharging from the initial core at Wolsong Unit 3 by slight change of camera and light. Inspectors could easily operate SCAI after several practices in the storage pond, which was a user friendly. And SCAI provided clear and immediate picture for identification of serial numbers of spent fuel bundles. It was interally evaluated that SCAI greatly contributed to cut inspection efforts for national and international safeguards at Wolsong power plant.

• Journal of the Korean Society for Nondestructive Testing
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• v.17 no.2
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• pp.89-99
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• 1997

Although discontinuously reinforced metal matrix composite(MMC) is one of the most promising materials for applications of aerospace, automotive industries, the thermal residual stresses developed in the MMC due to the mismatch in coefficients of thermal expansion between the matrix and the fiber under a temperature change has been pointed out as one of the serious problem in practical applications. There are very limited nondestructive techniques to measure the residual stress of composite materials. However, many difficulties have been reported in their applications. Therefore it is important to establish analytical model to evaluate the thermal residual stress of MMC for practical engineering application. In this study, an elastic model is developed to predict the average thermal residual stresses in the matrix and fiber of a misoriented short fiber composite. The thermal residual stresses are induced by the mismatch in the coefficient of the thermal expansion of the matrix and fiber when the composite is subjected to a uniform temperature change. The model considers two-dimensional in-plane fiber misorientation. The analytical formulation of the model is based on Eshelby's equivalent inclusion method and is unique in that it is able to account for interactions among fibers. This model is more general than past models to investigate the effect of parameters which might influence thermal residual stress in composites. The present model is to investigate the effects of fiber volume fraction, distribution type, distribution cut-off angle, and aspect ratio on thermal residual stress for in-plane fiber misorientation. Fiber volume fraction, aspect ratio, and distribution cut-off angle are shown to have more significant effects on the magnitude of the thermal residual stresses than fiber distribution type for in-plane misorientation.