• The Journal of Engineering Geology
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• v.15 no.4 s.42
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• pp.475-486
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• 2005

According to the inference results of formation process of the tectonic lineament, totally four events of subsidence including two events after upheaval of granite body and two events after sedimentation of unconsolidated sedimentary layer formed the macroscopic tensional lineament. The subsidence was occurred by tensional stress oriented ENE-WSW direction and compressional stress oriented NNW-SSE direction. The deeper distribution of tuff and unconsolidated sedimentary layer as much as 70-140m and that of granite as much as 50-500m at Hamdeok and Shinheung than those of the eastern and the western area around Hamdeok and Shinheong is due to the Hamdeok-Pyoseon Graben by three events of differential subsidence from Hamdeok to Pyoseon including Shinheung.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.110-110
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• 2018

여러 니켈합금 중 인코넬 600은 원전 가압경수로(PWR)의 튜브 재료로 널리 사용되는 재료이다. 스테인리스강과 비교하여 우수한 내식성과 기계적 특성으로 인해 화학설비, 발전설비, 그리고 해양설비 등과 같은 여러 산업분야에서도 널리 사용되고 있다. 그러나 가압경수로용 증기 발생기의 튜브 재료와 같은 특수 환경에서 예민화에 따른 입계부식 및 입계응력부식 등의 문제가 흔히 보고되고 있다. 이러한 내구성 문제는 설비 및 장비의 수명, 내구성 그리고 안정성 등의 치명적인 영향을 미친다. 따라서 용접, 열처리, 그리고 가공과정에서 발생하는 Inconel 600의 예민화 및 입계부식에 관한 연구가 활발히 진행되고 있다. 그러나 100시간 이상 장시간 열화된 시편에 대한 예민화 연구는 전무한 실정이다. 본 연구에서는 장시간 열화된 Inconel 600의 예민화를 평가하기 위해 최대 1,000시간까지 열화를 실시하였으며, 이에 대한 평가방법으로 Double-Loop Electrochemical Potentiokinetic Reactivation(DL-EPR) 시험법을 적용하였다. 본 실험에서 사용된 인코넬 600의 화학성분(wt, %)은 0.01 C, 0.05 Si, 0.14 Mn, 15.3 Cr, 0.5 Cu, 0.015 S, 그리고 나머지는 Ni 이다. 예민화 평가를 위한 등온 열화는 전기열처리로를 이용하여, $550^{\circ}C$와 $650^{\circ}C$에서 최대 1000시간까지 실시하였다. 열화에 따른 미세조직 변화는 scanning electron microscope와 energy dispersive x-ray spectroscopy를 이용하여 실시하였다. DL-EPR 실험은 $25^{\circ}C$의 0.1M $H_2SO_4$ + 0.001M KSCN(potasium thiocyanate) 수용액 하에서 실시하였으며, 분극은 OCP로부터 600 mV(SSE vs.)까지 1.67mV/s 주사속도로 forward scan을 실시 후, 동일한 속도로 OCP까지 reverse scan을 실시하였다. Degree Of Sensitization(DOS)값은 anodic scan peak($I_a$) 값과 reverse scan peak($I_r$) 값의 비로 산출하였다. $$i.e.\;DOS=I_r/I_a{\times}100$$. 그 결과, 온도 변수에 따른 Inconel 600강의 예민화 거동은 서로 상이한 경향을 나타내었다. $550^{\circ}C$의 경우, 열화가 진행됨에 따라 DOS값은 급격하게 증가하는 경향을 나타냈다. 반면, $650^{\circ}C$에서는 일정시간 이후부터 Cr 확산 현상에 의한 탈 예민화 현상이 관찰되었다.

• Korean Journal of Occupational Health Nursing
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• v.12 no.2
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• pp.110-122
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• 2003

Purpose: The purpose of this study is to make a systemic assessment on the level of self-efficacy, social support, and accessibility to medical services, health status, health promoting behaviors, and the quality of life of workers in small scale enterprises. RECEDE model developed by Green and Kreuter for the purpose of a comprehensive assessment research was used. Method: The number of subjects was 199 workers in small scale enterprises at Youngdeungpo-gu and Sungdonggu, Seoul. Data were collected between October and December, 200 through a self-reported questionnaire. And data were analyzed by descriptive statistics, t-test, and F-test. Result: 1. The level of quality of life was 3.08, and general health status was 2.75. There was no significant difference by sex, age, marital status, job, and perceived health status. 2. The level of health promotion life style was 2.09. There was no significant difference by sex, age, marital status, and job. But there was significant difference by perceived health status. 3. The level of self-efficacy, social support and accessibility to medical services were 3.04, 2.85, and 1.45. Conclusion: The results of this study suggest that it is necessary to develop the systematic health promotion programs that can strengthen self-efficacy and health status, and supplement social support and accessibility to medical services, and to encourage health promoting behavior in order to improve quality of life for workers in small scale enterprise.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.56 no.2
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• pp.114-125
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• 2020

In order to understand the currents around Hampyung Bay and Haeje Peninsula, 2D numerical simulations for tidal currents and tide-induced residual currents were carried out. Dominant semidiurnal tidal currents have reversing form and flow NNE-SSW from northern Haeje Peninsula to Songi Island, E-S at northern Haeje Peninsula and NNW-SSE in Hampyung Bay. In flood, a part of currents from Imja Island~Nakwhol Island flow along the main stream flowing northeast at offshore region and the rest flow into Hampyung Bay flowing east along the northern coast of Haeje Peninsula. In ebb, currents from Hampyung Bay flow west along the northern coast of Haeje Peninsula and run together with the main stream flowing southeast at offshore region. The currents create an anticyclonic circulation in flood and a cyclonic circulation in ebb around Haeje Peninsula including Hampyung Bay. Tidal currents are accumulated on Doripo which located at the entrance of Hampyung Bay and show high current velocities. Tidal currents and tide induced residual currents are weak at the inside of Hampyung Bay which has narrow entrance, shallow water depth and wide intertidal zone. An anticyclonic eddy is formed around Gaksi Island as a result of tide induced residual currents. In northern coast of Haeje Peninsula, slow constant currents flow east. It is expected that a gradual change of sediment and an increase of flushing time for suspended materials are carried by tidal currents occurring in Hampyung Bay.

• Korean Journal of Materials Research
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• v.23 no.11
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• pp.613-619
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• 2013

$Cu_2ZnSn(S_x,Se_{1-x})_4$ (CZTSSe) thin films were prepared by sulfurization of evaporated precursor thin films. Precursor was prepared using evaporation method at room temperature. The sulfurization was carried out in a graphite box with S powder at different temperatures. The temperatures were varied in a four step process from $520^{\circ}C$ to $580^{\circ}C$. The effects of the sulfurization temperature on the micro-structural, morphological, and compositional properties of the CZTSSe thin films were investigated using X-ray diffraction (XRD), Raman spectra, field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The XRD and Raman results showed that the sulfurized thin films had a single kesterite crystal CZTSSe. From the FE-SEM and TEM results, the $Mo(S_x,Se_{1-x})_2$ (MoSSe) interfacial layers of the sulfurized CZTS thin films were observed and their thickness was seen to increase with increasing sulfurization temperature. The microstructures of the CZTSSe thin films were strongly related to the sulfurization temperatures. The voids in the CZTSSe thin films increased with the increasing sulfurization temperature.

• Nuclear Engineering and Technology
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• v.47 no.3
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• pp.340-350
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• 2015

This paper proposes strain-based acceptance criteria for assessing plastic instability of the safety class 1 nuclear components made of ferritic steel during level D service loads. The strain-based criteria were proposed with two approaches: (1) a section average approach and (2) a critical location approach. Both approaches were based on the damage initiation point corresponding to the maximum load-carrying capability point instead of the fracture point via tensile tests and finite element analysis (FEA) for the notched specimen under uni-axial tensile loading. The two proposed criteria were reviewed from the viewpoint of design practice and philosophy to select a more appropriate criterion. As a result of the review, it was found that the section average approach is more appropriate than the critical location approach from the viewpoint of design practice and philosophy. Finally, the criterion based on the section average approach was applied to a simplified reactor pressure vessel (RPV) outlet nozzle subject to SSE loads. The application shows that the strain-based acceptance criteria can consider cumulative damages caused by the sequential loads unlike the stress-based acceptance criteria and can reduce the overconservatism of the stress-based acceptance criteria, which often occurs for level D service loads.

• Journal of the Korea Society of Computer and Information
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• v.11 no.1 s.39
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• pp.45-53
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• 2006

Finite failure NHPP models presented in the literature exhibit either constant, monotonic increasing or monotonic decreasing failure occurrence rates per fault. In this paper, Goel-Okumoto and Yamada-Ohba-Osaki model was reviewed, proposes the $x^2$ reliability model, which can capture the increasing nature of the failure occurrence rate per fault. Algorithm to estimate the parameters used to maximum likelihood estimator and bisection method, model selection based on SSE, AIC statistics and Kolmogorov distance, for the sake of efficient model, was employed. Analysis of failure using real data set, SYS2(Allen P.Nikora and Michael R.Lyu), for the sake of proposing shape parameter of the $x^2$ distribution using the degree of freedom, was employed. This analysis of failure data compared with the $x^2$ model and the existing model using arithmetic and Laplace trend tests, Kolmogorov test is presented.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.3
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• pp.407-414
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• 2015

The effect of activated carbon particle diameter (i.e. US sieve No. $8{\times}10$ ($d_p{\approx}2.19mm$), $18{\times}20$ ($d_p{\approx}0.92mm$), $50{\times}60$ ($d_p{\approx}0.27mm$) and $170{\times}200$ ($d_p{\approx}0.081mm$) on caffeine adsorption is investigated. BET surface area was increased with decreasing particle diameter ($d_p$), and caffeine adsorption rates increased with decreasing $d_p$. Moreover, pseudo-second order model is predicted the experimental data more accurately than pseudo-first order model, and the fastest rate constant ($k_2$) was $1.7g\;mg^{-1}min^{-1}$ when $d_p$ was 0.081 mm. Surface diffusion coefficient (Ds) was decreased with decreasing $d_p$ based on the minimum sum of square error (SSE). Practically, certain ranges of Ds are acceptable with high reliability ($R^2$) and it is determined that the effect of $d_p$ on Ds is unclear. The effect of pH on caffeine adsorption indicated the dependency of m/L ratio (mass liquid ratio) and $pH_{pzc}$. The $pH_{pzc}$ (i.e. $7.9{\pm}0.2$) was not affected by $d_p$. The higher caffeine adsorption at pH 4 and pH 7 than at pH 10 is due to $pH_{pzc}$, not $pk_a$ of caffeine.

• Journal of Biomedical Engineering Research
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• v.20 no.3
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• pp.291-297
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• 1999

Source consislency filtering (SCF) is very effective at removing nOIse when only one or a few leads among multi-lead ECG signals are contaminated. When the noise at one or only a few leads are statistically uncorrelated with signals at other leads, SCF seleclIvely removes the noise with a neglIgIble amount of distortion in the original signal waveform. In order to enhance the understanding of this new method, we describe the lheory and implementational details of SCF in this paper. Numerical implementation and test results of SCF on a multi-lead ECG dalabase show that SCF is a new kind of adaptive filters utilizmg spatial as well as temporal information in multi-c.hannel signals origmatmg from a single source. We also describe the limitations and future improvements in using SCF.

• Koreanishche Zeitschrift fur Deutsche Sprachwissenschaft
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• v.5
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• pp.375-398
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• 2002

Um von der 'kritischen' Situation des Faches DaF rauszukommen, werden viele Versuche untemommen, durch die Verbesserung des Untenichts in der Richtung nach der Entwicklung der kommunikativen $F\"{a}higkeit$ Deutsch als Fremdsprache wieder attraktiv und $konkurrenzf\"{a}hig$ zu machen. Aber leider sieht die Zwischenbilanz nicht so erfolgreich aus. Eine der Ursachen $daf\"{u}r\;l\"{a}sst$ sich mE. darin sehen, dass die $Ans\"{a}tze,\;die\;haupts\"{a}chlich\;f\"{u}r$ den Unterricht von Deutsch als Zweitsprache entwickelt wurden, ohne $gen\"{u}gende$ Berucksichtigung auf die kulturellen und institutionellen Unterschiede zwischen den Lemsituationen im zielsprachigen Land und im Heimatland der Schuler eingesetzt werden. In diesem Kontext $w\"{a}re\;es\;n\"{o}tig$, auf die Unterschiede zwischen DaF und DaZ und ihre Wirkung auf die Lehrstrategien im DaF-Unterricht zuruckzugreifen, Dabei sind auf einige Faktoren besonders zu achten, die DaF-Untenicht vom DaZ-Untenicht unterscheiden: die Mangel an den $M\"{o}glichkeiten$ der authentischen Kommunikation, die $Homogenit\"{a}t\;der\;Sch\"{u}ler$, die Lemkultur in der schlulischen Institution, das Alter, in dem die Sch\"{u}ler$ mit dem Lemen der Zielsprache beginnen. Daraus lassen sich die folgenden unterrichtlichen Konsequenzen ergeben: Die Lehrer sollten sich bemtihen, den $Sch\"{u}lern\;die\;M\"{o}glichkeiten\;f\"{u}r$ die authentischen Kommunikation besorgen, besonders $au{\ss}erhaib$ des Unterrichts, z.B. durch das Chatting- Projekt, $w\"{a}hrend$ im Unterricht mehr $Anl\"{a}sse\;f\"{u}r$ die Reflexion gegeben sollten. Und dabei sollten die unterrichtlichen Vorteile-die gemeinsame Muttersprache und Kultur, das Alter usw. - aktiv benutzt werden. Die meisten Koreaner beginnen $n\"{a}mlich$ mit dem Lernen der zweiten Fremdsprache erst in oder nach der $Pubert\"{a}t$. In diesem Zusammenhang sollte es auch betont werden, dass sich die Autonomie der Lerner durch den Unterricht richtig entwickelt, damit sie $sp\"{a}ter$ ihre Fertigkeiten autonom entwickeln $k\"{o}nnen$.