• Nuclear Engineering and Technology
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• v.46 no.6
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• pp.869-874
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• 2014

It was discovered in a Korean PWR that an extensive number of very short and shallow cracks in the SG tubes were undetectable by eddy current in-service-inspection because of the masking effect of sludge deposits. Axial stress corrosion cracks at the outside diameter of the steam generator tubes near the line contacts with the tube support plates are the major concern among the six identical Korean nuclear power plants having CE-type steam generators with Alloy 600 high temperature mill annealed tubes, HU3&4 and HB3~6. The tubes in HB3&4 have a less susceptible microstructure so that the onset of ODSCC was substantially delayed compared to HU3&4 whose tubes are most susceptible to ODSCC among the six units. The numbers of cracks detected by the eddy current inspection jumped drastically after the steam generators of HB4 were chemically cleaned. The purpose of the chemical cleaning was to mitigate stress corrosion cracking by removing the heavy sludge deposit, since a corrosive environment is formed in the occluded region under the sludge deposit. SGCC also enhances the detection capability of the eddy current inspection at the same time. Measurement of the size of each crack using the motorized rotating pancake coil probe indicated that the cracks in HB4 were shorter and substantially shallower than the cracks in HU3&4. It is believed that the cracks were shorter and shallower because the microstructure of the tubes in HB4 is less susceptible to ODSCC. It was readily understood from the size distribution of the cracks and the quantitative information available on the probability of detection that most cracks in HB4 had been undetected until the steam generators were chemically cleaned.

• The Journal of the Korean dental association
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• v.12 no.1
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• pp.29-34
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• 1974

In order to appreciate the school dental services of the primary, middle, and high school and to get the basic data for the university dental service programs in Korea, the author had examined the oral health status of 1,300 freshmen in S University. Then, the followed results were obtained from the calculation and evaluation of DEMT index, DT index, MT index, FT index, DT rate, MT rate, FT rate, debris deposit rate, calculus deposit rate, periodontal disease rate, and abnormal jaw relation rate. 1. DMFT index in the freshmen was higher than that of the Korean youth in the same age. 2. It seems the above result to be appeared from the influence of the intake of the more carbohydrate foods in the freshmen. 3. In the freshmen, MT rate was lower, and FT rate higher than in the Korean youth in the same age. 4. The oral hygiene condition was good in 3.15% of the freshmen. 5. Calculus was not deposited in 8.69% of the freshmen. 6. In 9.69% of the freshmen, the periodontium was healthy. 7. In Korea, the school dental services in the primary, middle, and high schools must be improved. 8. There was the abnormal jaw relation in 12.92% of the freashmen.

• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.879-882
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• 2008

Abroad service of domestic academic thesis is very important for the enhancement of cited counting and Korea journals acknowledgement. The basis is to register DOI, the international academic thesis identifier at each thesis. It requires uneasy process depositing academic thesis to CrossRef which manages and registers DOI. KISTI has been conducting DOI/CrossRef deposit business object to domestic societies in scientific and technical field. In this thesis, we designed and implemented academic thesis DOI enrollment supporting system which is able to manage the required process on the online for the DOI/crossRef deposit business.

• Korean Journal of Metals and Materials
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• v.48 no.11
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• pp.1014-1020
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• 2010

In order to improve the purity on deposit in cobalt electrowining, a fundamental study using Pulse-Reverse Current (PRC) was carried out. Based on a sulfate solution, Cu, Ni, and Fe as impurities were added during cobalt electrowinning. There were four reverse waveforms and frequency conditions from 1 Hz to 10 kHz, and the purity of each condition was compared with the Direct Current (DC) purity. From the results, it was found that the anodic potential induced by reverse current affects selective dissolution of impurities. In this work, the case of the highest reverse peak current density ($I_r$) with a short reverse time ($t_r$) at 100 Hz showed a higher purity than that of the DC. This PRC condition also showed only a 4% low current efficiency comparable to the DC. We concluded that an optimized PRC for cobalt electrowinning could improve the purity with little loss of current efficiency.

• Spatial Information Research
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• v.9 no.1
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• pp.15-30
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• 2001

Solid waste collection service is viewed as one of the most important public services in urban area. The purpose of this study is to apply the GIS based regional partitioning and arc routing methods for solid waste collection districting and vehicle routing-scheduling in order to provide waste collection service more efficiently. In this study, solid waste deposit sites are derived from the centroid of each building and the amount of solid waste is deduced based on the number of households and establishments. The regional partitioning procedure is performed based on waste collection zones which are constructed from waste deposit sites. The result of this study shows that solid waste collection districts which are delineated by regional partitioning method are able to increase efficiencies and cut costs in performing solid waste collection services. Also the output of vehicle-scheduling from the analysis of arc routing may provide more efficiently and quickly manage the scheduling of the residential solid waste collection routes, reducing costs with minimal deadheading costs. Therefore, the application of GIS based on regional partitioning and arc routing methods would be very useful to construct a solid waste management system by supplying the important and flexible informations for solid waste collection districts and vehicle routing-scheduling for waste collection.

• Journal of the Korean Home Economics Association
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• v.38 no.11
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• pp.63-75
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• 2000

To identify the actual situation of financial information disclosure, a content analysis was performed on pamphlets of a time deposit and a new reserve trust offered by banks and other financial institutes. Although consumers required information on interest rate, tax favor, loan service, protection of brink depositors and bank security to select a financial service account, informations offered on pamphlets are not sufficient. Therefore concrete way of information offer system shoed be developed. In offering interest rate, interest rate after tax deduction or payment at maturity should be also mentioned. Information on tax favor, protection of bank depositors and bank security should be contained in pamphlets as well. Use of easy terms and notes are recommended for developing pamphlets for financial products.

• Korean Journal of Materials Research
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• v.25 no.11
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• pp.612-615
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• 2015

In this work, on-site corrosion behavior of heat resistant tubes of T91, used as components of a superheater in a power plant for up to 25,762 h, has been investigated using scanning electron microscopy(SEM), energy dispersive X-ray spectroscopy (EDS), and electron backscattered diffraction(EBSD), with the objectives of studying the composition, phase distribution, and evolution during service. A multi-layer structure of oxide scale was found on both the steamside and the fireside of the tube surface; the phase distribution was in the order of hematite/magnetite/spinel from the outer to the inner matrix on the steamside, and in the order of slag/magnetite/spinel from the outer to the inner matrix on the fireside. The magnetite layer was found to be rich in pores and cracks. The absence of a hematite layer on the fireside was considered to be due to the low oxygen partial pressure in the corrosion environment. The thicknesses of the hematite and of the slag-deposit layer were found to exhibit no significant change with the increase of the service time.

• Corrosion Science and Technology
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• v.16 no.6
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• pp.285-293
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• 2017

The effects of sulfate reducing bacteria (SRB) on the corrosion and scaling of the Q235 carbon steel has been investigated in the simulated sewage water and oil field gathering pipelines production water, using scanning electron microscopy (SEM), energy dispersive x-ray spectrometry (EDS), and three-dimensional stereoscopic microscope. Results indicated that the concentration of SRB reached the maximum value on the ninth day in simulated sewage water with a large amount of scaling on the surface of specimen. In oil field gathering pipelines, a large amount of scaling and mineralization of mineral salts and thick deposition of extracellular polymeric substance (EPS) layers were also observed on the surface of specimen. The thickness of biofilm was about $245{\mu}m$ within 30 days. After adding microbicides, the thickness of corrosion products film was only up to $48-106{\mu}m$ within 30 days, suggesting that SRB could induce biomineralization. Under-deposit corrosion morphology was uniform in the absence of microbicides while local corrosion was observed in the presence of microbicides.

• Journal of Digital Convergence
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• v.18 no.1
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• pp.287-293
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• 2020

This study is about comparing and analyzing the representative fintech application service, Toss, and Kakaobank from the user's point of view and suggest development according to the main factors of user experience. The experimental group who have used both mobile application was recruited to do a task about deposit and withdrawal service. After the task, an in-depth interview was conducted by reorganizing the "Creating Pleasurable Interface model" by Stephen P. Anderson. Interview questionnaire is based on propensity and feature of generation 2030. As a result of the experiment, the user showed satisfaction with usability and showed different application usage experience depend on financial transaction propensity and money management. Therefore, the application needs features that could grasp the propensity and also service to manage money in everyday life. Based on this study, it is expected to develop be user-based fintech application service in related fields.

• Korean Management Science Review
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• v.28 no.1
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• pp.107-116
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• 2011

The automated teller machine (ATM) is developed as a system to provide customers with an easy deposit and withdrawal of their money without time restriction and be served for 24 hours. Today, ATM is come up to the level of an unmanned branch. The automatic financing system is developed as an essential one for dealing with the rationalization of management and the globalization of financing in order to improve the efficiency of financial management work and increase the customer service quality. With reducing the operational cost of financial organizations through the efficient maintenance operation of ATM and increasing the service quality through the maximization of its processing efficiency, this study is to draw the scheme to ensure the competitiveness among the finance companies. The importance of ATM is highly recognized as the utilization of ATM is increased and the processing function is extended, but ATM is quite vulnerable to the malfunction occurred during the nighttime after banking hours. The ATM maintenance is done through consignment to the specialized maintenance company. The efficient operation of ATM maintenance work is important to the satisfaction of customer using ATM in the nighttime.