• EDISON SW 활용 경진대회 논문집
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• 제4회(2015년)
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• pp.151-155
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• 2015

The molecular interactions between the nucleic acid bases and water molecules are important in organism. Despite Adenine-Thymine Hoogsteen base pair and Guanine-Cytosine Watson-Crick base pair have been demonstrated to be most stable in a gas phase, the effect of water on the stability of these base pairs remains elusive. Here we report the structural and thermodynamic characteristics on possible Adenine-Thymine and Guanine-Cytosine base pairs in a gas phase as well as in an aqueous phase by using quantum mechanical method and statistical mechanical calculations. First, we optimized the direct base-pair interaction energies of four Adenine-Thymine base pairs (Hoogsteen base pair, reverse Hoogsteen base pair, Watson-Crick base pair, and reverse Watson-Crick base pair) and three Guanine-Cytosine base pairs (GC1 base pair, GC2 base pair, and Watson Crick base pair) in a gas phase at the $B3LYP/6-31+G^{**}$ level. Then, the effect of solvent was quantified by the electronic reorganization energy and the solvation free energy by statistical mechanical calculations. Thereby, we discuss the effect of water on the stability of Adenine-Thymine and Guanine-Cytosine base pairs, and argue why Adenine-Thymine Watson-Crick base pair and Guanine-Cytosine Watson-Crick base pair are most stable in an aqueous environment.

• 설비공학논문집
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• 제17권12호
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• pp.1185-1191
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• 2005

Published correlation equations of the enthalpy of vaporization are reviewed and a new four-parameter correlation equation is proposed. Performance of the proposed equation is examined using the ASHRAE data for 22 pure substance refrigerants as reference data. The new equation yields an average absolute deviation of $0.05\%$, which is smaller than those of published equations, such as equations of Guermouche-Vergnaund $(0.08\%)$, Aerebrot $(0.13\%)$, Radoz-Lydersen $(0.08\%)$, and Somayajulu $(0.08\%)$. The three adjustable parameters of the modified correlation are optimized and reported for 22 substances. The equation proposed in this work is valid over the entire temperature range where data points exist.

• Advances in aircraft and spacecraft science
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• 제4권1호
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• pp.1-19
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• 2017

Fatigue life prediction of a multi-row countersunk riveted lap joint was performed numerically. The stress and strain conditions in a highly stressed substructure of the joint were analysed using a global/local finite element (FE) model coupling approach. After validation of the FE models using experimental strain measurements, the stress/strain condition in the local three-dimensional (3D) FE model was simulated under a fatigue loading condition. This local model involved multiple load cases with nonlinearity in material properties, geometric deformation, and contact boundary conditions. The resulting stresses and strains were used in the Smith-Watson-Topper (SWT) strain life equation to assess the fatigue "initiation life", defined as the life to a 0.5 mm deep crack. Effects of the rivet-hole clearance and rivet head deformation on the predicted fatigue life were identified, and good agreement in the fatigue life was obtained between the experimental and the numerical results. Further crack growth from a 0.5 mm crack to the first linkup of two adjacent cracks was evaluated using the NRC in-house tool, CanGROW. Good correlation in the fatigue life was also obtained between the experimental result and the crack growth analysis. The study shows that the selected methodology is promising for assessing the fatigue life for the lap joint, which is expected to improve research efficiency by reducing test quantity and cost.

• 한국안전학회지
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• 제26권3호
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• pp.1-7
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• 2011

Fatigue damage on the train wheel surface was estimated by considering the effect of friction coefficient of rolling on the contact surface between the wheel and rail during operation. From FEM analys, the maximum Tresca stress was 550.7 MPa at a depth of 2.07 mm under the maximum contact pressure ($P_{max}$ = 894.3 MPa) between wheel and rail. The maximum stress continued to increase along with the increase in the frictional coefficient. The fatigue initiation lifetime of the wheel by the rolling contact was predicted using the Smith-Watson-Topper (SWT) equation and the maximum principal strain equation (${\varepsilon}$-N).

• 한국안광학회지
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• 제19권4호
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• pp.505-511
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• 2014

목적: 호흡 알코올 농도를 제한한 상태에서 알코올 섭취로 인한 호흡 알코올 농도(breath alcohol concentration, BrAC) 증가가 대비감도에 미치는 영향을 알아보았다. 방법: 20대의 남성 23명(평균연령 $21.17{\pm}2.19$세, body mass index(BMI) $22.09{\pm}2.16$)을 대상으로 Watson 공식을 기반으로 개발된 BAC(blood alcohol concentration) Dosing Software를 이용하여 호흡 알코올 농도 0.05%와 0.08%에 도달하기 위한 알코올 양을 산정하여 투여한 후 다양한 휘도(명소시, 박명시, 박명시 눈부심) 상태에서 대비감도를 측정하여 비교 분석하였다. 결과: 호흡 알코올 농도가 증가할수록 모든 공간주파수에서 대비감도는 감소하였다. 정점대비감도는 명소시 상태에서 6 cycle per degree(cpd), 박명시 상태에서 3 cpd로서 호흡 알코올 농도가 증가하여도 정점이동이 나타나지 않았지만, 박명시 눈부심 상태에서는 0%와 0.05%에서는 6 cpd, 0.08%에서는 3 cpd로서 호흡 알코올 농도 증가에 따른 정점이동이 나타났다. 결론: 음주에 의한 호흡 알코올 농도 증가는 모든 공간주파수에서 대비감도의 감소와 정점대비감도의 이동을 유발함으로써 다양한 시작업에 영향을 미치고 안전사고의 원인이 될 수 있으므로 주의하여야 한다.

• 한국안광학회지
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• 제20권2호
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• pp.187-193
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• 2015

목적: 현행법상 음주 단속의 측정기준이 되는 호흡 알코올 농도(BrAC) 증가가 시력과 타각적 굴절검사 값에 미치는 영향을 알아보고자 하였다. 방법: 23명의 20대 남성(평균연령 $21.17{\pm}2.19$세, BMI $22.09{\pm}2.16$)을 대상으로 호흡 알코올 농도 0%, 0.05%, 0.08%에서 원 근거리 시력검사와 개방형 자동굴절력계를 이용한 타각적 굴절검사를 시행하였다. 결과: 호흡 알코올 농도가 증가할수록 원거리 시력은 통계적으로 유의하게 감소하였고 근거리 시력은 변화하지 않았다. 또한 호흡 알코올 농도가 증가할수록 타각적 굴절검사 값은 (-) 방향으로 증가하는 경향을 보였다. 결론: 음주로 인한 호흡 알코올 농도 증가는 교정시력의 감소와 교정굴절력이 (-) 방향으로 증가하는 원인이 될 수 있으므로 시력검사와 굴절검사는 비음주상태에서 진행해야 할 필요성이 있다.

• 한국엔터테인먼트산업학회논문지
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• 제15권5호
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• pp.99-113
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• 2021

본 연구는 거시경제요인이 스포테인먼트 산업에 미치는 영향을 확인하여 그 활용 가치를 발견하기 위한 연구다. 연구를 위해 거시경제요인으로 DJIA, WTI, GP를 선택하였고, 스포테인먼트 산업을 대표할 만한 자료로 NIKE와 Adidas 주가를 선택하였으며, 20년 5,285일간의 거래 자료를 2단계 추출 과정을 거쳐 분석하였다. 분석 결과 첫째, 거시경제요인은 스포테인먼트 산업에 유의한 영향을 미치는 것으로 나타났다. 둘째 시간의 설정, 각 시기의 특성, 그리고 요인 간 관계에 따라 각기 다른 수준의 회귀식이 나타났다. 마지막으로, 시계열분석을 통한 미래 예측 방법인 Durbin-Watson 검증 결과 특정 시기의 특정 요인 간 회귀식은 미래 예측에 활용 가능한 것으로 나타났지만, 각 조건에 따라 각각 다른 결과가 관찰되어 향후 후속 연구가 필요하다 판단된다.

• Journal of Ecology and Environment
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• 제40권3호
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• pp.136-143
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• 2016

Background: Mussels are stubborn organisms attached to solid substrata by means of byssus threads. The abundance of marine mussel Mytilus edulis in marine facilities like power stations was reason to select among fouling animals. Methods: Mortality patterns as well as physiological behavior (oxygen consumption, foot activity, and byssus thread production) of two different size groups (14- and 25-mm shell length) of M. edulis were studied at different hydrogen peroxide concentrations ($1-4mg\;l^{-1}$). Results: Studied mussels showed progressive reduction in physiological activities as the hydrogen peroxide concentration increased. Mussel mortality was tested in 30 days exposure, and 14 mm mussels reached the highest percentage of 90% while 25 mm mussels reached 81%. Produced data was echoed by Chick-Watson model extracted equation. Conclusions: This study points that, while it could affect the mussel mortality moderately in its low concentrations, hydrogen peroxide has a strong influence on mussels' physiological activities related to colonization. Therefore, hydrogen peroxide can be an alternative for preventing mussel colonization on facilities of marine environment.

• Structural Engineering and Mechanics
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• 제24권2호
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• pp.213-225
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• 2006

The propagation of non-uniformly modulated, evolutionary random waves in viscoelastic, transversely isotropic, stratified materials is investigated. The theory is developed in the context of a multi-layered soil medium overlying bedrock, where the material properties of the bedrock are considered to be much stiffer than those of the soil and the power spectral density of the random excitation is assumed to be known at the bedrock. The governing differential equations are first derived in the frequency/wave-number domain so that the displacement response of the ground may be computed. The eigen-solution expansion method is then used to solve for the responses of the layers. This utilizes the precise integration method, in combination with the extended Wittrick-Williams algorithm, to obtain all the eigen-solutions of the ordinary differential equation. The recently developed pseudo-excitation method for structural random vibration is then used to determine the solution of the layered soil responses.

• 대한간호학회지
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• 제49권1호
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• pp.80-91
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• 2019

Purpose: This study attempted to develop a scale that measures the level of patients' recognition of the nurses' care, based on Watson's caring theory, and confirmed its reliability and validity. Methods: The items were developed through a literature review and an expert content validity test. The questionnaires were administered to 285 inpatients of internal medicine and surgical units at two general hospitals. Construct validity was tested using exploratory and confirmatory factor analysis, and reliability was tested using Cronbach's alpha. Results: This process resulted in a preliminary scale composed of 34 items; We used item analysis and five exploratory factor analyses, and consequently selected 14 items composed of three factors (respect, genuineness, and relationality). The confirmatory factor analysis verified the model fit and convergent and discriminant validity of the final items; criterion validity was confirmed with the positive correlation with the measurement scale of the patient-perceived quality of nursing. The overall scale reliability had a Cronbach's alpha of .92, which indicated internal consistency and reliability. Conclusion: The developed scale showed content, construct, and criterion validity, and reliability, as well as convergent validity for each item and discriminant validity between the factors. This makes it suitable for use in a diverse range of future studies on nurse communication using structural equation models.