• Progress in Superconductivity and Cryogenics
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• v.16 no.2
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• pp.29-32
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• 2014

The critical current, $I_c$ of HTS superconducting tapes can be measured by transport or contactless method. Practically, the transport method using the four-probe method is the most common. In this study, a simple test procedure by clipping the voltage lead taps have been introduced instead of soldering which reduces time and effort and thereby achieving a much faster measurement of $I_c$. When using a pair of iron clips, $I_c$ value decreased as compared with the measured one by standard method using soldered voltage taps and varies with the width of the clipped specimen part. However, when using a pure Cu clip, both by clipping and by soldering voltage taps give a comparable result and $I_c$ measured are equal and close to the samples specification. As a result, material to be used as voltage clip should be considered and should not influence the potential voltage between the leads during $I_c$ measurement. Furthermore, the simulation result of magnetic flux during $I_c$ measurement test showed that the decrease of $I_c$ observed in the experiment is due to the magnetic flux density, $B_y$ produced at the clipped part of the sample by the operating current with iron clips attached to the sample.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.176-180
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• 2001

There are several factors causing re-work in CMP process such as improper polish time calculation by operator, removal rate decline of the polisher, unstable in-suit pad conditioning, slurry supply module problem and wafer carrier rotation inconsistency. And conclusively those fundimental reason for the re-work rate increasement is mainly from the cycle time delay between wafer polish and post measurement. Therefore, Wafer thickness measurement in wet condition could be able to remove those improper process conditions which may happen during the process in comparison with the conventional dried wafer measurement system and it can be able to reduce the CMP process cycle time. CMP scrap reduction by overpolish, re-work rate reduction, thickness control efficiency also can be easily achieved. CMP Equipment manufacturer also trying to develop integrated system which has multi-head & platen, cleaner, pre & post thickness measure and even control the polish time from the calculated removal rate of each polishing head by software. CMP re-work problem such as over & under polish by target thickness may result in the cycle time delay. By reducing those inefficient factors during the process and establish of the automatic process control, CLC system need to be adopted to maximize the process performance. Wafer to Wafer Polish Time Feed Back Control by measuring the wafer right after the polish shorten the polish time calculation for the next wafer and it lead to the perfect Post CMP target thickness control capability. By Monitoring all of the processed the wafer, CMP process will also be stabilize itself.

• Smart Media Journal
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• v.11 no.1
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• pp.9-16
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• 2022

With the development of online commercializing technology and the growth of online market, it has become extremely important for companies that aim to commercialize their products and services to control time and resources. Even when a single company has control over the entire process, it is necessary to maintain the efficiency among the process of development. In particular, when there is a lot of cooperation throughout the course of development, requiring many parties to communicate with each other, the issue of declining efficiency becomes much clearer. The timing of when to launch a product or service has become just as important as completing and testing them for companies. Companies have developed new tools to prevent situations that may lead to inefficiency in the development process, including an increase in the amount of resource used or issues with security maintenance. However, there is a lack of proper measurement tool that assesses what kind of additional benefits the entire process of the company is bringing, or whether or not the processes need to be improved in certain areas. Thus, this study aims to suggest a method to measure efficiency, to provide an empirical efficiency measurement method for the development process of online content.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.490-497
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• 2016

This study compared and analyzed the pollution levels of radiation shielding aprons and ways to sterilize them using 30 lead aprons. After collecting samples from the center of the lead apron, where contact is most frequent, experiments were conducted employing Coagula and Latex methods. Using the culture medium where bacteria grew, measurements of the pathogen count and identification were performed. The greatest number of pathogens were $7.16{\pm}10$, which were detected on the lead apron from general X-ray room #2, but there was no significant difference according to the facilities (p > 0.05). Compared to how many pathogens remained between using the disinfectant ethanol and tissue, the pathogens decreased by $0.01{\pm}0.4$ (p < 0.05) after using disinfectant ethanol and by $0.87{\pm}1.7$(p < 0.05) after using disinfectant tissue. The Pearson correlation test revealed a significant correlation (-0.296, p < 0.05) between them. According to this research, there were pathogens on the lead aprons and the number of pathogens was determined by statistical analysis. It is expected that the rate of radiology technologists, patients, and medical equipment infected by pathogens will be reduced by the proper use of sterilization with a disinfectant ethanol.

• Journal of the Korean Society of Radiology
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• v.5 no.3
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• pp.135-141
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• 2011

If protective performance of apron cannot be good, radiation exposure of an guardian or a patient, a person engaged in radiation related industry cannot rise. Therefore, It will be evaluated protection performance to radiation protection aprons by manufacturers and lead equivalent more than 0.25mm lead equivalent. And, will show in the direction of application to clinic. The new aprons by manufacturers(H, X, I, J company) and lead equivalent(0.50mmPb, 0.35mmPb, 0.25mmPb) measured transmitted dose rate and shielding rate, uniformity under fluoroscopy and general radiography using to fluoroscopy system and digital radiography system, x-ray multifunction meter. The shielding rate measurement results, 0.5mmPb apron was Shielding rate of apron of a I company(fluoroscopy : 97.96%) was the best under six companies, and shielding rate of apron of a J company(fluoroscopy : 96.25%) was worst. 0.35mmPb Apron was Shielding rate of a I company(fluoroscopy : 96.79%) was the best under the three companies, and shielding rate of an H company(fluoroscopy : 95.81%) was the worst. 0.25mmPb Apron was Shielding rate of X company apron(fluoroscopy : 90.908%) was better than H company apron(fluoroscopy : 88.82%) than two companies. The uniformity measurement results, 0.5mmPb Aprons of X company(fluoroscopy : 0.13) and I company(fluoroscopy : 0.19) was the best under the six companies, and J company apron(fluoroscopy : 0.45) was the worst. 0.35mmPb. Along a manufacturer and lead equivalent performance of apron protection is distinguished certainly. Therefore, a patient, guardian or a person engaged in radiation related industry shall enforce experiment of a lot of ways defined or evaluation so that the maximum reduces radiation exposure. Buy the apron that protective performance is good, It will be performed through experiment and evaluation.

• Progress in Medical Physics
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• v.9 no.3
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• pp.137-141
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• 1998

The purposes of this report are to evaluate whether lead ball and steel ball could be used as protective material of radiation and to acquire physical data of them for protecting 4-10 MV X-ray beams. Lead balls of diameter 2.0～2.5mm or steel balls of diameter 1.5～2.0 mm were filled in an acrylic box of uniform width. An MV radiograph of metal balls in a box were taken to ascertain uniformity of ball distribution in the box. Average density of metal ball and linear attenuation coefficient of metal balls for 4～10 MV X -rays were measured. At the time of measurement of linear attenuation coefficient, Farmer ionization chamber was used and to minimize the scatter effect, distance between the ball and the ionization chamber was 70 cm and field size was 5.5cm${\times}$5.5cm. For comparison, same parameters of lead and steel plates were measured. The distribution of metal balls was uniform in the box. The density of a mixture of lead-air was 6.93g/cm$^3$, 0.611 times density of lead, and the density of a mixture of steel-air was 4.75g/cm$^3$, 0.604 times density of steel. Half-value layers of a mixture of lead-air were 1.89 cm for 4 MV X-ray, 2.07 cm for 6 MV X-ray and 2.16 cm for 10 MV X-ray, and approximately 1.64 times of HVL of lead plate. Half-value layers of a mixture of steel-air were 3.24 cm for 4 MV X-ray, 3.70 cm for 6 MV X-ray and 4.15 cm for 10 MV X-ray, and approximately 1.65 times of HVL of lead plate. Metal balls can be used because they could be distributed evenly. Average densities of mixtures of lead-air and steel-air were 6.93g/cm$^3$, 4.75g/cm$^3$ respectively and approximately 1.65 times of densities of lead and steel. Product of density and HVL for a mixture of metal-air are same as the metal.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.4 no.1
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• pp.17-24
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• 1994

The urinary excretion of ${\delta}$-aminolevulinic acid has been widely used as a measure of the biological effect of lead in lead exposed workers. It is usually measured by colorimetric method based on the color reaction of ALA-pyrrole with Ehrlich's reagent. But the results of ${\delta}$-ALA in urine by this method are somewhat artificially higher than expected due to the urinary ALA-like compound such as aminoacetone. On the other hand, the recently developed fluorometric HPLC method is very sensitive and specific for the measuring urinary ALA. In order to compare the data obtained by two methods and to investigate the interrelation between two methods, 117 lead workers with different lead exposure were checked urinary ${\delta}$-ALA, blood lead and other lead exposure related indices. The results obtained are as follows; 1. Urinary excretion of ${\delta}$-ALA by colorimetric method is 2.15 times higher than HPLC method in overall, revealing 2.47 times in workers of blood lead less than $20{\mu}g/dl$, 2.53 times in workers of blood lead $21-40{\mu}g/dl$ and 1.86 times in workers of blood lead over $41{\mu}g/dl$, respectively. 2. While the correlation coefficients of ${\delta}$-ALA measured by colorimetric method with blood lead and blood ZPP was 0.571 and 0.629, those of ${\delta}$-ALA measured by HPLC with blood lead and blood ZPP were 0.6l0 and 0.637. All the correlation coefficients were statistically significant, but there was no statistical difference of correlation coefficients between two methods. 3. The correlation coefficient of urinary excretion of ${\delta}$-ALA between two method was 0.838 without any correction, but it was 0.852 with the correction of specific gravity 1.024. 4. Simple linear regression of ${\delta}$-ALA measured by HPLC method on ${\delta}$-ALA measured by colorimetric method was (ALA-UPH)=-0.245+0.536 (ALA-UCO) without any correction and it was (SP ALA)=-0.525+0.598 (SP ALA-UCO) with the correction of specific gravity 1.024. With above results, it is recommended that the diagnostic criteria of ${\delta}$-ALA for lead poisoning needed to be revised if ${\delta}$-ALA is measured by HPLC rather than colorimetric method.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.6
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• pp.1102-1108
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• 2008

Wearable physiological signal monitoring systems are regarded as an important sensing unit platforms in ubiquitous/mobile healthcare application. In this paper, we suggested the modified bipolar electrodes implemented on the portable heart activity monitoring system, which minimized the distance of electrodes formed on a attachable pad. The proposed electrode configuration is useful in mobile measurement environments, but has a disadvantage of reduced amplitude of the heart action potential. In order to overcome the shortcoming of the suggested electrode configuration, we implemented the amplifying circuit to increase the signal-gain and decrease the artifacts. For evaluations, we analyzed the specificity of measured cardiography using the proposed electrodes through the comparing of heart activity monitoring system with standard clinical ECG(lead2) by pearson correlation coefficients. The result showed that the average correlation coefficient is $0.903{\pm}0.036,\;0.873{\pm}0.072$ at V3, V4 chest lead position, respectively. Thus, the modified bipolar electrode is quite suitable to monitor the electrical activity of the heart in the situation of the mobile environment, and could be considered having high similarity with standard clinical ECG.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.7
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• pp.91-98
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• 2009

A reliable tensile test technique for PDP's barrier rib materials was introduced. A tensile specimen was prepared by punching out of green sheet, curing the specimen in a high temperature furnace, attaching sand paper tabs on each grip ends, and then attaching two strain gages for the strain monitoring and specimen alignment. Preliminary tensile tests were successfully done with the specimens made from ZnO-based lead-free green sheet. The specimens cured at 3 different maximum curing temperatures were tested to demonstrate the applicability of the test method. The Young's modulus was 88 ${\pm}$ 4 GPa regardless of the maximum curing temperature. The ultimate tensile strength was decreased with increasing the temperature. The tensile test method proposed in this study was proven to be reliable, useful and easy to estimate the bulk mechanical properties of barrier rib materials.

• Journal of Korean Ophthalmic Optics Society
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• v.4 no.2
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• pp.165-169
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• 1999

The thermal diffusivity of lead germanate single crystal was measured from room temperture up to the $200^{\circ}C$ by heating method. The thermal diffusivities were measured as k=0.0117, 0.0105, and $0.0112cm^2/^{\circ}C$ at $30^{\circ}C$, $177^{\circ}C$, and $180^{\circ}C$, respectively. It is identified that the heat capacity of the lead germanate single crystal is maximum at $177^{\circ}C$, and this point is phase transition temperature of $Pb_5Ge_3O_{11}$ single crystal.