• Proceedings of the Korean Nuclear Society Conference
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• 1995.05a
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• pp.680-686
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• 1995

It has been known that water-side corrosion of fuel rods in nuclear reactor is accompanied with the loss of metallic wall thickness and pickup of hydrogen. This corrosion is one of the important limiting factors ill the operating life of fuel rods. In connection with the fuel cladding corrosion, a device to measure the water-side oxide layer thickness by means of the eddy-current method without destructing the fuel rod was developed by KAERI. The device was installed on the multi-function testing bench in the nondestructive test hot-cell and its calibration was carried out successfully for the standard rod attached with plastic thin films whose thicknesses are predetermined. It shows good precision within about 10% error. And a PWR fuel rod, one of the J-44 assembly discharged from Kori nuclear power plant Unit-2, has been selected for oxide layer thickness measurements. With the result of data analysis, it appeared that the oxide layer thicknesses of Zircaloy cladding vary with the length of the fuel rod, and their thicknesses were compared with those of the destructive test results to confirm the real thicknesses.

• Journal of Sensor Science and Technology
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• v.25 no.1
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• pp.35-40
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• 2016

Pulse diagnosis is one of the representative diagnostic methods in Oriental medicine. In this study, a pulse pressure sensor array coated with silicone, which includes 6 piezo-resistive sensors and 1 thermistor, is fabricated for pulse measurement. It is necessary to coat the pulse sensor array with silicone to avoid the fracture or damage of pressure sensors when the sensor is in contact with the skin and a constant pressure is applied. However, the silicone coating on the pulse sensor array can cause signal interference among the sensors in the pulse sensor array. The interference number (IN), a calculation for expressing the degree of interference among channels, is changed according to the silicone thickness on the pulse sensor array. The IN is increased by a thick silicone coating, but the fabrication error, an important index for the mass production of the sensor array, is reduced by the thickness of the silicone coating. We propose that the thickness of the silicone on the pulse sensor array is an important consideration for the performance of the fabricated sensor and manufacturing repeatability.

• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.2
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• pp.170-176
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• 2012

In the nuclear industry, wall thinning defect of straight pipe occur the enormous loss in life evaluation and safety evaluation. To use non-destructive technique, we measure deformation, vibration, defect evaluation. But, this techniques are a weak that is the measurement of the wide area is difficult and the time is caught long. In the secondary side of nuclear power plants mostly used steel pipe, artificiality wall thinning defect make in the side and different thickness make to the each other, wall thinning defect part of deformation measure by using shearography. In addition, optical measurement through deformation, vibration, defect evaluation evaluate pipe and thickness defects of pressure vessel is to evaluate quantitatively. By shearography interferometry to measure the pipe's internal wall thinning defect and the variation of pressure use the proposed technique, the quantitative defect is to evaluate the thickness of the surplus. The amount of deformation use thickness of surplus prediction of the actual thickness defect and approximately 7 percent error by ensure reliability. According to pressure the amount of deformation and the thickness of the surplus through DB construction, nuclear power plant pipe use wall thinning part soundness evaluation. In this study, pressure vessel of thickness defect measure proposed nuclear pipe of wall thinning defect prediction and integrity assessment technology development. As a basic research defected theory and experiment, pressure vessel of advanced stability and soundness and maintainability is expected to contribute foundation establishment.

• Journal of the Korean Society of Physical Medicine
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• v.11 no.1
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• pp.83-91
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• 2016

PURPOSE: There are several methods, such as the abdominal drawing-in maneuver (ADIM), maximal expiration (ME), and Kegel exercise, to strengthen the core muscles. However, to date no study has been conducted to compare the effects of the ADIM, ME, and Kegel exercise on the transverses abdominis (TrA), internal oblique (IO), external oblique (EO), and pelvic floor muscles (PFMs). The purpose of this study was to find out which of the three aforementioned exercises is most effective for contracting the core muscles. METHODS: The thickness of the TrA, IO, EO and PFMs was measured by ultrasonographic imaging during the ADIM, ME and Kegel exercise in 34 healthy participants. RESULTS: There was the significant difference between ADIM and Kegel exercise in the thickness of the TrA (p<0.05). There were the significant differences between ADIM and ME and between ME and Kegel exercise in the thickness of the IO and PFM (p<0.01). There was no significant activation in the thickness of the EO (p>0.05). Measurement reliability was assessed using intraclass correlation coefficients (ICC) and the standard error of measurement (SEM). An ICC value of >0.77 indicated that reliability measurements was good. CONCLUSION: Kegel exercise was the most effective exercise for the TrA and the PFM, and ME was the most effective exercise for the IO muscles.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.9
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• pp.84-89
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• 2021

Indium tin oxide (ITO) transparent electrodes, which are used to manufacture organic light-emitting diodes, are used in light-emitting surface electrodes of display EL panels such as cell phones and TVs, liquid crystal panels, transparent switches, and plane heating elements. ITO is a major component that consists of indium and tin and is advantageous in terms of obtaining sheet resistance and light transmittance in a thin film. However, the optical performance of devices decreases with an increase in its thickness. A digital holography system was constructed and measured for the step measurement of the ITO thin film, and the reliability of the technique was verified by comparing the FE-SEM measurement results. The error rate of the step difference measurement was within ±5%. This result demonstrated that this technique is useful for applications in advanced MEMS and NEMS industrial fields.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.127-130
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• 1997

Phase-contrast(PC) methods have been used for quantitative measurements of velocity and volume flow rate. In addition, phase contrast cine magnetic resonance imaging (MRI) combines the flow dependent contrast of PC MRI with the ability of cardiac cine imaging to produce images throughout the cardiac cycle. In this method, the through-plane velocity has been encoded generally. However, the accuracy of the flow data can be reduced by the effect of flow direction, finite slice thickness, resolution, pulsatile flow pattern, and so on. In this study we calculated the error caused by misalignment of tomographic plane and flow directon. To reduce this error and encode the velocity for more complex flow, we suggested 3 directional velocity encoding method.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1066-1069
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• 2004

Recently the monitoring system of tool setup in high speed precision machining tool is required for manufacturing products that have highly complex and small shape, high precision and high function. It is very important to reduce time to setup tool in order to improve the machining precision and productivity and to protect the breakage of cutting tool as the shape of product is smaller and more complex. Generally, the combination of errors that geometrical clamping error of fixing tool at the spindle of machining center and the asynchronized error of driving mechanism causes that the run-out of tool reaches to 3∼20 times of the thickness of cutting chip. And also the run-out is occurred by the misalignment between axis of tool shank and axis of spindle and spindle bearing in high speed rotation. Generally, high speed machining is considered when the rotating speed is more than 8,000 rpm. At that time, the life time of tool is reduced to about 50％ and the roughness of machining surface is worse as the run-out is increased to 10 micron. The life time of tool could be increased by making monitoring of tool-setting easy, quick and precise in high speed machining center. This means the consumption of tool is much more reduced. And also it reduces the manufacturing cost and increases the productivity by reducing the tool-setup time of operator. In this study, in order to establish the concept of tool-setting monitoring the measuring method of the geometrical error of tool system is studied when the spindle is stopped. And also the measuring method of run-out, dynamic error of tool system, is studied when the spindle is rotated in 8,000 ∼ 60,000 rpm. The dynamic phenomena of tool-setup is analyzed by implementing the monitoring system of rotating tool system and the noncontact measuring system of micro displacement in high speed.

• Journal of Radiation Protection and Research
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• v.36 no.1
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• pp.16-23
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• 2011

Accurate measurement of uranium enrichment is very important in nuclear material accountability. The analysis uncertainty of the uranium enrichment measurement with gamma-ray analysis was studied in the present work. FRAM (Fixed energy Response function Analysis with Multiple efficiencies) code was used to determine the uranium enrichment. If the shield materials were placed between the detector and the sample, the error was measured and analyzed. Measurement time was varied and the dependency of the analysis uncertainty on the measurement time was studied. Transmitted gamma-ray intensities and FWHMs of the peaks in the energy spectrum were measured as the shield thickness was varied. The transmitted gamma-ray intensity follows shape of the exponential function, and the FWHM was almost independent of the shield thickness. The uncertainty of FRAM analysis was studied when the thick shield material was placed between the detector and the sample. Our work could be helpful in analysis of the fissile material in uranium sample.

• Fire Science and Engineering
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• v.33 no.2
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• pp.39-46
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• 2019

This study assessed the measurement errors and improvement of the spatial resolution through miniaturization of the plate thermometer used to measure the heat flux in a fire environment. As a result, the heat loss to the side of plate thermometer was found to have a significant influence on the measurement error through analysis of the measurement values according to the thickness and density change to the insulation installed on the back side of the plate. Based on the existing 10 cm square shape, it was also confirmed that the 3 cm size plate thermometer could measure the heat flux with satisfactory accuracy through miniaturization. These results are expected to be useful for accurate measurements of the heat flux at local locations in a fire environment.

• Korean Journal of Optics and Photonics
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• v.27 no.4
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• pp.143-150
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• 2016

The thickness of each layer in a multilayered system is determined by a Fourier-transform method using spectroscopic reflectance measurements. To verify this method, we first generate theoretical reflectance spectra for three layers, and these are fast-Fourier-transformed using our own Matlab program. Each peak of the Fourier-transformed delta function denotes the optical thickness of each layer, and these are transformed to physical thicknesses. The relative thickness error of the theoretical model is less than 1.0% while a layer's optical thickness is greater than 730 nm. A PI-(thin $SiO_2$)-PImultilayeredstructure produced by the bar-coating method was analyzed, and the thickness errors compared to SEM measurements. Even though this Fourier-transform method requires knowing the film order and the refractive index of each layer prior to analysis, it is a fast and nondestructive method for the analysis of multilayered structures.