• 공업화학
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• 제20권3호
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• pp.346-350
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• 2009

자연상태의 물질들은 많은 유용한 성분들을 포함하고 있다. 이 성분들 중에서, 천연 영양 성분들은 기능성 식품 또는 화장품, 의약품의 첨가제로써 활용 되고 있다. 이러한 영양성분들을 유용하게 활용하기 위해 각 성분들에 대한 최적의 용매 선택방법을 제시하였다. 각 성분에 대한 용해도 파라미터를 계산하였으며 총 용해도 파라미터는 분산성, 극성, 수소결합 효과로 구성되고 이들 기여도가 각각 계산되었다. 용질과 용매의 용해도 파라미터에 의해 chi(${\chi}_{12}$)파라미터가 결정되었으며 chi파라미터에 의해 아미노산 성분들에 대한 최적의 용매-용질쌍이 선정되었다.

• Coupled systems mechanics
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• 제12권1호
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• pp.83-102
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• 2023

First introduced in 2016, the dynamic foundation model is an interesting topic in which the foundation is described close to reality by taking into account the influence of the foundation mass in the calculation of oscillation and is an important parameter that should be considered. In this paper, a follow-up investigation is conducted with the object of the Mindlin plate on a nonlinear dynamic foundation under moving loads. The base model includes nonlinear elastic springs, linear Pasternak parameters, viscous damping, and foundation mass. The problem is formulated by the finite element analysis and solved by the Newmark-β method. The displacement results at the center of the plate are analyzed and discussed with the change of various parameters including the nonlinear stiffness, the foundation mass, and the load velocity. The dynamic response of the plate sufficiently depends on the foundation mass.

• 한국진공학회지
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• 제12권1호
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• pp.20-24
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• 2003

Parametric semiconductor model을 이용하여 $In_{\chi}Ga_{1-\ch}As \;(0\leq\chi\leq1)$ 화합물 반도체 박막의 유전함수를 얻었다. Parametric model은 Gaussian-broadened polynomial들의 합으로 임계점에 대한 모델 유전 함수를 묘사하여 InGaAs 화합물의 광학 상수들을 재현할 수 있는 parameterized 함수를 제공하였다. 이러한 parametric 모델을 통하여 임의의 성분비 $\chi$에 대한 파라미터 값들을 얻었고, 이렇게 얻어진 파라미터들로부터 $In_{\chi}Ga_{1-\ch}As \;(0\leq\chi\leq1)$ 화합물 박막의 임의의 성분비에 대한 유전 함수를 얻을 수 있었다.

• Advances in nano research
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• 제12권5호
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• pp.441-455
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• 2022

This study explores the linear and nonlinear solutions of sigmoid functionally graded material (S-FGM) nanoplate with porous effects. A size-dependent numerical solution is established using the strain gradient theory and isogeometric finite element formulation. The nonlinear nonlocal strain gradient is developed based on the Reissner-Mindlin plate theory and the Von-Karman strain assumption. The sigmoid function is utilized to modify the classical functionally graded material to ensure the constituent volume distribution. Two different patterns of porosity distribution are investigated, viz. pattern A and pattern B, in which the porosities are symmetric and asymmetric varied across the plate's thickness, respectively. The nonlinear finite element governing equations are established for bending analysis of S-FGM nanoplates, and the Newton-Raphson iteration technique is derived from the nonlinear responses. The isogeometric finite element method is the most suitable numerical method because it can satisfy a higher-order derivative requirement of the nonlocal strain gradient theory. Several numerical results are presented to investigate the influences of porosity distributions, power indexes, aspect ratios, nonlocal and strain gradient parameters on the porous S-FGM nanoplate's linear and nonlinear bending responses.

• 한국한의학연구원논문집
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• 제14권2호
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• pp.107-112
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• 2008

Although the pulse diagnosis position, Guan is apart from Cun or Chi by only $10{\sim}20$ mm at most, traditional medical doctors applies different indent pressures and even they states different pulse images are felt at Cun, Guan and Chi, To support their clinical behaviors, in this study, we tested statistically whether there are differences in pulse waveform measured at these three positions with SphygmoCor system used world widely, A 30 years old female subject without any evidence of cardiovascular diseases was involved in this experiment. Radial pulse waves were recorded at three different positions on left lower arm 10 times at three positions-Cun, Guan and Chi. With ANOVA, we tested whether, among three different positions. there are any differences in 12 parameters of radial pulse waveform and in estimated AIx(Augmentation Index) as an arterial stiffness index extracted from radial pulse waveform. As results, differences in optimal indent pressure h0 were observed at different measuring positions(P<0.001) but not significantly different. And pulse pressure his were found to be different(Chi$22.60{\pm}3.06%,\;18.60{\pm}3.37%\;and\;26.4{\pm}5.02%$ respectively. Consequently. AIx at Gwan seems to be lowest and that at Chi seems to be highest. So. we assert the AIx at Chi is likely to be overestimated. In further studies. we want to examine what make differences in these parameters between measuring positions. And it also seems to be worthy to investigate the relationship between the depth of radial artery and AIx. And, ultimately, we need to determine the best measuring process including measuring position, hold-down pressure, signal quality validation and so on. so to achieve the optimal waveform which represents subject's health condition for both western medicine and traditional medicine.

• Computers and Concrete
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• 제27권5호
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• pp.395-406
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• 2021

This study experimentally and analytically investigates the shear behavior of corroded reinforced concrete (RC) beams repaired using steel fiber-reinforced concrete (SFRC) in the flexural zone. The experimental parameters are the corrosion degree (0%, 12%, and 17%) and the steel fiber volume in the SFRC (1.0%, 1.5%, and 2.0%). The test results reveal that corrosion degree significantly affects the shear resistance of the beams. The shear capacity of the beam with the corrosion degree of 17% was higher than that of the uncorroded beam, whereas the shear capacity of the beam with the corrosion degree of 12% was lower than that of the uncorroded beam. The shear efficiency of damaged beams can be recovered by repairing them using SFRC that contains a reasonable amount of steel fibers. In addition, two methods to estimate the shear capacity of the repaired beams are developed using the modified truss analogy and strut-and-tie models. The estimated shear capacity of the beam using the modified truss analogy model agrees well with the experimental data.

• Yonsei Medical Journal
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• 제59권9호
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• pp.1138-1142
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• 2018

This study aimed to analyze the impact of sleep deprivation (SD) on cardiac, hemodynamic, and endothelial parameters and to determine whether these are sustained with increased periods of SD. The study included 60 healthy men (mean: age $31.2{\pm}6.3years$; body mass index $24.6{\pm}2.6kg/m^2$). Hemodynamic parameters, parameters of myocardial contractility, spectral analysis of heart rate (HR) and blood pressure (BP) variability, and the sensitivity of arterial baroreflex function were evaluated. Biochemical tests were performed to assess L-arginine (L-Arg) and asymmetric dimethylarginine (ADMA) levels in reflection of endothelial nitric oxide synthase ability. Measurements of cardiovascular system parameters were obtained at 9 a.m. (baseline) on the first day of the study and 9 a.m. (24-h SD), 1 p.m. (28-h SD), and 5 p.m. (32-h SD) on the second day. Blood samples for evaluating biochemical parameters were obtained at baseline and after 24-h SD. ANOVA Friedman's test revealed a significant effect for time in relation to HR (${\chi}^2=26.04$, df=5, p=0.000), systolic BP (${\chi}^2=35.98$, df=5, p=0.000), diastolic BP (${\chi}^2=18.01$, df=5, p=0.003), and mean BP (${\chi}^2=28.32$, df=5, p=0.000). L-Arg and ADMA levels changed from $78.2{\pm}12.9$ and $0.3{\pm}0.1$ at baseline to $68.8{\pm}10.2$ and $0.4{\pm}0.1$ after 24-hr SD, respectively (p=0.001, p=0.004). SD in healthy men is associated with increases in BP, which appear to occur after 24 hours of SD and are maintained over increasing periods of SD. The observed hemodynamic changes may have resulted due to disordered vascular endothelial function, as reflected in alterations in L-Arg and ADMA levels.

• 한국산학기술학회논문지
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• 제12권3호
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• pp.1458-1464
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• 2011

본 연구는 유출분석을 위하여 수문학적 모델에 근거한 지형적인 특성을 반영한 TOPMODEL의 적용성을 평가하는 것이다. 적용대상은 섬진강 상류유역에 위치한 산악지역으로서 쌍치 소유역이고, 유역면적은 $126.7km^2$이다. 2006~2009년에 선택된 6시간 간격의 강우-유출 자료를 가지고 Pattern Search 방법에 의한 관측유출자료를 사용하여 모델의 매개변수들을 조정하였다. 쌍치 유역의 지형학적인 인자들은 $100m{\times}100m$ 격자의 수치 표고모델에 의하여 추출하였다. 분석결과에 의하면 모델의 매개변수인 지수저류 매개변수(m), 투수량계수(T0), 불포화대 지체시간(TD)등은 수문학적인 반응에 민감하였으며, 모의된 유출자료는 관측 유출자료와 잘 일치하여 합리적인 적용성을 보인다.

• Bulletin of the Korean Chemical Society
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• 제26권7호
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• pp.1065-1070
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• 2005

$[Mn_{12}O_{12}(O_2CPh-4-SMe)_{16}(H_2O)_4]{\cdot}7CH_2Cl_2$ (1), a new single-molecule magnet complex has been successfully synthesized by substitution of acetate ligand of Mn12ac with 4-(methylthio)benzoic acid. Complex 1 crystallizes into triclinic P$\overline{1}$ with a = 18.321(3) $\AA$, b = 19.011(3) $\AA$, c = 27.230(4) $\AA$, $\alpha$ = 86.973(3)$^{\circ}$, $\beta$ = 76.919(3)$^{\circ}$, $\gamma$ = 87.613(3)$^{\circ}$, and Z = 2. In complex 1, one Mn(III) ion has an abnormal Jahn-Teller elongation axis oriented at an oxide ion. Complex 1 has two out-of-phase ac susceptibility peaks in the 2-4 K and 4-7 K regions. Effective anisotropy energy barrier and pre-exponential factor are $U_{eff}$ = 45.95 K, 1/$\tau$0 = 8.6 ${\times}\;10^9s^{-1}\;for\;{\chi}_M$'' peaks in the lower temperature region and $U_{eff}$ = 59.45 K, 1/$\tau_0$ = 2.2 ${\times}\;10^8\;s^{-1}$ for $\chi_M$'' peaks in the higher temperature region. The parameters of S = 10, g = 1.87, D = -0.40 $cm^{-1}$, and E = 0.00034 $cm^{-1}$ were obtained from the M/N${\mu}_B$ vs. H/T plot of complex 1.

• Archives of Pharmacal Research
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• 제17권2호
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• pp.80-86
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• 1994

The bioavailability of digoxin generic tablets manufactures in Korea (formulations A & B) wwere compared to a standard (formulation C; Lanoxin brand digoxin, Burroughs Wellcome, USA) in 12 healthy Korean male volunteers (mean age 31.4 years) in a single dose, randomized, complete block crossover study. Using a latin square design, each of the subjects was randomized to the order number and allocated to each of the three treatments of 0.5mg oral digoxin. Digoxin conc4ntrations in serum and urine samples collected for 48 hours after dosing were measured by fluoprescence polarization immunoassy and radioimmunoassy, respectively. Treatments were compared by using nonlinear least squares regession analysis to evaluate the following pharmacokinetic parameters : maximum serum concentation $(C_{max})$; time of maximum serum concentation $(T_{max})$; area under the serum concentration-time curve $AUC_{0-12}$, $C_{max}$\;and\;(AUC_{0-12})$; and cummulative urinary excretion for 0-48 hours $(CLE_{0-48}.\;Mean\;AUC_{0-12},\;C_{max},\;and\;CUE_{0-48}$ values for formulations B and C were significantly different from formulation A (P<0.001), but not significantly diffeerent form each other. Basede on $AUL_{0-12}\;and\;CUE_{0-48}$ respectively, the relative availability of formulation B was 87.5% and 89.6% and the relative availability of formultation A was 43% and 35% when compared to formulation C(the standard).