• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2002년도 춘계공동학술발표회요약집
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• pp.201.1-201
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• 2002

• Bulletin of the Korean Chemical Society
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• 제26권9호
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• pp.1421-1426
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• 2005

The stationary point structures and relative energies between them as well as binding energies of $(CO)_2$ have been investigated at the CCSD(T) level using the correlation-consistent basis sets aug-cc-pVXZ(X=T,Q,5). It is found that while the equilibrium structure corresponds to the C-bonded T-shaped configuration with intermolecular distance of 4.4 $\AA$, there exists another minimum, slightly higher in energy ($\sim$10 $cm^{-1}$) than the global minimum, corresponding to the O-bonded T-shaped configuration with the intermolecular distance of 3.9 $\AA$. The CCSD(T) basis set limit binding energy of $(CO)_2$ is estimated to be 132 $cm^{-1}$.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.648-653
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• 2003

In order to predict stress intensity limit of high-temperature creep structures, creep work-time equation, defined as $W_ct^P=B$, was used, and the results of the equation were compared with isochronous stress-strain curve (ISSC) ones of ASME BPV NH Code. For this purpose, the creep strain tests with. time variations for commercial type 316 stainless steel were conducted with different stresses; 160 MPa, 150 MPa, 145 MPa, 140 MPa and 135 MPa at $593^{\circ}C$. The results of log $W_c$ and log t plots showed a good linear relation up to $10^5$ hr. The constants p, B and stress intensity limit values showed comparatively good agreement to those of ASME NH ISSC. It is believed that the relation can be simply obtained with only several short-term 1% strain data without ISSC which can be obtained by long-term creep data.

• 한국국방경영분석학회지
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• 제6권2호
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• pp.129-149
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• 1980

In medical follow-up, equipment lifetesting, various military situations, and other fields, one often desires to calculate survival probability as a function of time, p(t). If the observer is able to record the time of occurrence of the event of interest (called a 'death'), then an empirical, non-parametric estimate may simply by obtained from the fraction of survivors after various elapsed times. The estimation is more complicated when the data are truncated, i.e., when the observer loses track of some individuals before death occurs. The product-limit method of Kaplan and Meier is one way of estimating p(t) when the mechanism causing truncation is independent of the mechanism causing death. This paper proposes jackknife estimators of logistic trans-formation and compares it to the product-limit method. A computer simulation is used to generate the times of death and truncation from a variety of assumed distributions.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제6권2호
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• pp.1-8
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• 2002

Let $T_{\phi}$ be a generalized Gauss transformation and $[a_1,\;a_2,\;{\cdots}]_{T_{\phi}}$ be a symbolic representation of $x{\in}[0,\;1)$ induced by $T_{\phi}$, i.e., generalized continued fraction expansion induced by $T_{\phi}$. It is shown that the distribution of relative frequency of [$k_1,\;{\cdots},\;k_n$] in $[a_1,\;a_2,\;{\cdots}]_{T_p}$ satisfies Central Limit Theorem where $k_i{\in}{\mathbb{N}}$ for $1{\leq}i{\leq}n$.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2001년도 추계학술발표회요약집
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• pp.347.2-347
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• 2001

• 한국해양공학회지
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• 제7권2호
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• pp.131-140
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• 1993

To study the corrosion fatigue begavior of T.M.C.P. steel, the rotary bending fatigue test with the change of concentration of NaCl solution was carried out. Fatigue life in the corrosion environment is decreased markedly in comparision with that in the air. Fatigue limit in the air was about 225 MPa. In case of 3.5% NaCl solution fatigue life could be expressed as .sigma./sub f/=10,392 * (N/sub f/)/sup -o.2923 . According to the paris's rule, crack growth rates could be expressed as da/dN=2.62.*10/sup -7/ .DELTA. K/sup 1.09/(3.5% NaCl solution), da/dN=1.95 *10/sup -7 .DELTA. K/sup 1.05/(1% NaCl solution), da/dN=2.62 * 10/sup -7/.DELTA./sup 0.72/(0.01% NaCl solution) with da/dN expressed in mm/cycle and .DELTA.K in MPa.GAMMA.m. The crack growth rate in the corrosion environment was highest under 3.5% NaCl solution.

• Geomechanics and Engineering
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• 제7권4호
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• pp.431-458
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• 2014

Construction of a new cavern close to an existing cavern will result in a modification of the state of stresses in a zone around the existing cavern as interaction between the twin caverns takes place. Extensive plane strain finite difference analyses were carried out to examine the deformations induced by excavation of underground twin caverns. From the numerical results, a fairly simple nonparametric regression algorithm known as multivariate adaptive regression splines (MARS) has been used to relate the maximum key point displacement and the percent strain to various parameters including the rock quality, the cavern geometry and the in situ stress. Probabilistic assessments on the serviceability limit state of twin caverns can be performed using the First-order reliability spreadsheet method (FORM) based on the built MARS model. Parametric studies indicate that the probability of failure $P_f$ increases as the coefficient of variation of Q increases, and $P_f$ decreases with the widening of the pillar.

• Bulletin of the Korean Chemical Society
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• 제34권4호
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• pp.1101-1107
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• 2013

In this study, total mercury and methyl mercury in whole blood of Korean was analyzed so as to investigate the correlation between total mercury (T-Hg) and methyl mercury (Me-Hg). 4000 whole blood samples were divided in four groups, according to T-Hg concentration in percentile: group I (p25-p50), group II (p50-p75), group III (p75-p95) and group IV (p95-p100). 100 samples were randomly selected from the each group, and Me-Hg concentration was measured. T-Hg concentration in whole blood was analyzed using a Direct Mercury Analyzer-80 and obtained limit of detection (LOD) was $0.2{\mu}gL^{-1}$. Me-Hg concentration was analyzed with ethylate derivatization using headspace-gas chromatography-mass spectrometry, and obtained LOD of methyl mercury was $0.5{\mu}gL^{-1}$. The geometric means of T-Hg and Me-Hg were $6.35{\mu}gL^{-1}$ and $4.44{\mu}gL^{-1}$, respectively, and 71.91% of T-Hg was presented as Me-Hg.

• 산업기술연구
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• 제31권A호
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• pp.135-145
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• 2011

This study was conducted to analyze the cost effectiveness in line with total phosphorus standard enforcement of public sewage treatment facilities. The additional cost for the total phosphorus removal process was calculated to analyze the cost effectiveness of the advanced water purification process. The analysis results showed that the T-P removal by coagulation sedimentation was more efficient than the advanced water purification facilities in terms of facilities investment cost, and if the coagulation filteration was used for T-P removal, the activated carbon process among the advanced water purification techniques was more efficient in terms of facilities investment cost. In this study, the effects of the T-P removal process that will be additionally introduced according to the tightening of the effluent T-P standard were analyzed within a limit. The actual benefits of improved T-P concentration in the water source will provide diverse values, including the leisure water, environment improvement water, eco-system in the water source and industrial water, in addition to the advanced water purification.