• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.1403-1405
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• 2004

The method proposed by Carson contains indefinite complex integral which simulates earth return current. Although the Carson solution is proposed with power series, the solution is limited and valid at special range of frequency. We proposed a simplified Carson solution by modelling earth current path analytical method using ground transmission line return current. In this paper, we studied on trying to find the equivalent distance for earth current return path.

• 한국구조물진단유지관리공학회 논문집
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• 제22권5호
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• pp.13-22
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• 2018

이 연구는 이방성 평판의 휨 해석을 위한 지배방정식을 유도하고 다양한 경계조건을 갖는 평판의 정확한 풀이과정을 제시하였다. 이 해법은 삼각급수를 이용하여 미분 방정식을 대수학적 방정식으로 변환시키는 전통적인 Navier와 Levy의 방법을 따랐다. Levy의 방법을 이용해 해를 구하려면 평판의 마주보는 두 끝단이 단순지지단인 경우에만 가능하다. Navier의 방법은 사각평판의 네 끝단이 모두 단순지지단 이어야 한다. 본 연구는 Navier와 Levy해법이 갖는 경계조건 한계를 극복하였다. 이 해법은 평판 네 끝단의 경계조건이 단순지지단과 고정단의 어떤 조합이라도 적용될 수 있다. 하중조건도 분포하중, 부분하중 그리고 선하중에 대해 적용할 수 있다. 이 해법의 장점은 Navier와 Levy해법이 갖는 경계조건 한계를 극복하였을 뿐만 아니라 정확한 해를 구할 수 있다. 비대칭 경계조건을 갖는 이방성평판에 대하여 이 해법을 이용한 계산결과를 나타냈다. 또한 Navier해법과 Levy해법 그리고 Szilard의 계산결과와 비교를 보여주었는데 계산된 처짐량이 잘 일치한다.

• 대한본초학회지
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• 제20권2호
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• pp.1-6
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• 2005

Objectives : The purpose of this study is to investigate genetic toxicity of Cervi pantotrichum Cornu herbal acupuncture solution(CPCHA). Methods : In this study, a series of investigation have been carried out to analyze the effects of Cervi pantotrichum Cornu herball acupuncture solution(CPCHA) on colony forming ability of NIH3T3cells, Hela cells and adrenorectal coloncell for genetic toxicity test. Results and Conclusions : From the above results, it is suggested that Cervi pantotrichum Cornu herball acupuncture solution(CPCHA) was limited 0.5-10ug/ml by test. Cervi pantotrichum Cornu herball acupuncture solution(CPCHA) did not exert the protective role to the genetic toxicity in kinds of cell lines used in this study. From these results, Cervi pantotrichum Cornu herbal aqua-acupuncture solution needs further study to prove it's function in cell culture system.

• 멤브레인
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• 제25권3호
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• pp.239-247
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• 2015

새로운 형태의 포스파젠 진단막을 제조해 혈액 속의 글루코우즈의 농도를 측정하였다. 혈액 속에 존재할 가능성이 높은 장애성분들을 4가지 그룹으로 분류하여 혈당 측정에 미치는 영향을 조사하였다. 가장 낮은 농도를 나타내는 시리즈 I의 경우, 대부분의 첨가물들이 혈당 측정에 큰 영향을 미치지 않았으나, 오직 ascorbic acid (AA)만이 기준 용액보다 5~8% 정도 높은 K/S 결과치를 나타내었다. 시리즈 II의 경우, 네 가지 첨가물 모두 기준 용액의 K/S 결과치보다 3~4% 다소 낮은 값을 보였으나 농도에 따른 일정한 값을 보여 주었다. 시리즈 III의 경우, 세 가지 첨가물 모두 기준 용액에서 얻어지는 K/S 결과치와 큰 차이를 보이지 않았다. 가장 높은 농도를 나타내는 시리즈 IV의 경우, 두 가지 물질 모두가 기준 값보다 11~15% 정도 낮은 수치를 나타내었으나 혈당 측정에 크게 영향을 주지는 않았다.

• 한국해양공학회지
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• 제36권2호
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• pp.101-107
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• 2022

Dean (1965) proposed the use of the root mean square error (RMSE) in the dynamic free surface boundary condition (DFSBC) and kinematic free-surface boundary condition (KFSBC) as an error evaluation criterion for wave theories. There are well known wave theories with RMSE more than 1%, such as Airy theory, Stokes theory, Dean's stream function theory, Fenton's theory, and trochodial theory for deep-water waves. However, none of them can be applied for deep-water breaking waves. The purpose of this study is to provide a closed-form solution for deep-water waves with RMSE less than 1% even for breaking waves. This study is based on a previous study (Shin, 2016), and all flow fields were simplified for deep-water waves. For a closed-form solution, all Fourier series coefficients and all related parameters are presented with Newton's polynomials, which were determined by curve fitting data (Shin, 2016). For verification, a wave in Miche's limit was calculated, and, the profiles, velocities, and the accelerations were compared with those of 5^th-order Stokes theory. The results give greater velocities and acceleration than 5^th-order Stokes theory, and the wavelength depends on the wave height. The results satisfy the Laplace equation, bottom boundary condition (BBC), and KFSBC, while Stokes theory satisfies only the Laplace equation and BBC. RMSE in DFSBC less than 7.25×10^-2% was obtained. The series order of the proposed method is three, but the series order of 5^th-order Stokes theory is five. Nevertheless, this study provides less RMSE than 5^th-order Stokes theory. As a result, the method is suitable for offshore structural design.

• International Journal of Naval Architecture and Ocean Engineering
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• 제13권1호
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• pp.50-56
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• 2021

An accurate evaluation of three-dimensional (3D) Time-Domain Green Function (TDGF) in infinite water depth is essential for ship's hydrodynamic analysis. Various numerical algorithms based on the TDGF properties are considered, including the ascending series expansion at small time parameter, the asymptotic expansion at large time parameter and the Taylor series expansion combines with ordinary differential equation for the time domain analysis. An efficient method (referred as "Present Method") for a better accuracy evaluation of TDGF has been proposed. The numerical results generated from precise integration method and analytical solution of Shan et al. (2019) revealed that the "Present method" provides a better solution in the computational domain. The comparison of the heave hydrodynamic coefficients in solving the radiation problem of a hemisphere at zero speed between the "Present method" and the analytical solutions proposed by Hulme (1982) showed that the difference of result is small, less than 3%.

• 대한화학회지
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• 제9권4호
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• pp.185-189
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• 1965

韓國産 酸性白土類 및 silica gel을 aniline yellow, o-nitro aniline, oil orange 色素 benzene 溶液과 작용시켜 非水溶液에서의 色素吸着率을 측정하였다. 그 吸着率은 silica gel이 酸性白土類보다 컸으며 酸性度에는 무관하였다. 또 上記 色素溶液에 각 10%의 添加溶劑 amine, alcohol, halogen類 化合物등을 加하여 高體酸의 色素吸着率의 변화(吸着阻害率)에 대하여 조사한 결과 위에 적은 順으로 그 영향이 적어지고, 同族體에서는 分子量이 적을 수록 그 영향이 커짐을 알았다. 따라서 非水溶液에서의 吸着은 amine基, 水酸基등과 같은 陰性基를 갖는 化合物은 選擇吸着하고 界面張力에 무관계하여 Traulbe系列의 逆轉現象을 나타내었다. 그 逆轉現象(吸着潮害現象)은 그 順位가 添加溶制의 雙極子能率과 대체적으로 일치하는 것으로 보아 固體酸模體인 活性硅酸과 被吸着體사이의 極盛的化學吸着에 의한 것이라 推定된다. 本實驗結果로부터 固體酸의 非水溶液에서의 吸着메카니즘, Traube 系列의 逆轉現象에 관하여 考察하게 되었다.

• Steel and Composite Structures
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• 제27권1호
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• pp.1-12
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• 2018

This paper presents a semi-analytical solution of simply supported horizontally composite curved I-beam by trigonometric series. The flexibility of the interlayer connectors between layers both in the tangential direction and in the radial direction is taken into account in the proposed formulation. The governing differential equations and the boundary conditions are established by applying the variational approach, which are solved by applying the Fourier series expansion method. The accuracy and efficiency of the proposed formulation are validated by comparing its results with both experimental results reported in the literature and FEM results.

• 한국해양공학회지
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• 제11권2호
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• pp.57-69
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• 1997

The objetive of this study is to compare the mechanical proprties of 6000 series Al-Mg-Si aluminum alloy (AC120) with 5000 series Al-Mg aluminum alloy (TG25), and to investigate the influence of corrosion solution for fatigue life. Comparing of TG25 and AC120 alloy sheets, TG25 alloy sheets showing higher plastic ratio and total elongation have better formability than AC120 alloy sheets. The hardness of nugget area was a little higher than that of base metal area. Also, grain coarsening was observed in HAZ(Heat Affected Zone). In a corrosion fatigue experiment, the fatigue life decreased as concentration increased, when a dipping time was constant. The life decreased as dippling time increased, when a concentration was constant.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2004년도 학술대회지
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• pp.221-231
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• 2004

A kinetic theory analysis is made of low-speed gas flows in a microfluidic system consisted of three microchannels in series. The Boitzmann equation simplified by a collision model is solved by means of a finite difference approximation with the discrete ordinate method. For the evaluation of the present method results are compared with those from the DSMC method and an analytical solution of the Navier-Stokes equations with slip boundary conditions. Calculations are made for flows at various Knudsen numbers and pressure ratios across the channel. The results compared well with those from the DSMC method. It is shown that the analytical solution of the Navier-Stokes equations with slip boundary conditions which is suited fur fully developed flows can give relatively good results. In predicting the geometrically complex flows up to a Knudsen number of about 0.06. It is also shown that the present method can be used to analyze extremely low-speed flow fields for which the DSMC method is Impractical.