• 한국도서관정보학회지
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• 제53권3호
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• pp.25-46
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• 2022

본고에서는 레코드 컨티뉴엄에서의 평가 논리를 분석하였다. 전자기록 환경에서의 평가가 지닌 보다 근원적인 함의를 파악하기 위해서는 레코드 컨티뉴엄에 내재되어 있는 평가 논리에 대한 분석이 필수적으로 요구된다. 레코드 컨티뉴엄은 기존의 라이프사이클을 기반으로 한 평가 논리 및 여기서 연유한 양분화된 기록관리체제에 대한 반론에서 출발한 이론체계라는 점에서, 전자기록 환경에서의 평가에 관한 이론적 기반을 제공해 줄 수 있다. 특히 평가는 기록이 지닌 의미를 모색하는 합목적적 행위임을 감안할 때, 레코드 컨티뉴엄에서 의도한 기록의 개념 및 의미에 대한 재해석은 이전과는 다른 평가상의 논리들을 도출할 수 있게 해준다. 이에 본고에서는 라이프사이클 평가 논리와의 비교 및 레코드 컨티뉴엄에서 제시한 새로운 기록에 대한 인식을 기반으로, 레코드 컨티뉴엄 평가 논리상의 핵심 요소를 세 가지 측면에 초점을 맞추어 분석하였다.

• Steel and Composite Structures
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• 제25권3호
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• pp.257-270
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• 2017

In this article, an efficient and simple refined theory is proposed for buckling analysis of functionally graded plates by using a new displacement field which includes undetermined integral variables. This theory contains only four unknowns, with is even less than the first shear deformation theory (FSDT). Governing equations are obtained from the principle of virtual works. The closed-form solutions of rectangular plates are determined. Comparison studies are carried out to check the validity of obtained results. The influences of loading conditions and variations of power of functionally graded material, modulus ratio, aspect ratio, and thickness ratio on the critical buckling load of functionally graded plates are examined and discussed.

• Advances in materials Research
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• 제6권2호
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• pp.93-128
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• 2017

In this paper, thermal vibration behavior of nanoscale beams made of functionally graded (FG) materials subjected to various types of thermal loading are investigated. A Reddy shear deformation beam theory which captures both the microstructural and shear deformation effects without the need for any shear correction factors is employed. Material properties of FG nanobeam are assumed to be temperature-dependent and vary gradually along the thickness according to the power-law form. The influence of small scale is captured based on nonlocal elasticity theory of Eringen. The nonlocal equations of motion are derived through Hamilton's principle and they are solved applying analytical solution. The comparison of the obtained results is conducted with those of nonlocal Euler-Bernoulli beam theory and it is demonstrated that the proposed modeling predict correctly the vibration responses of FG nanobeams. The effects of nonlocal parameter, material graduation, mode number, slenderness ratio and thermal loading on vibration behavior of the nanobeams are studied in detail.

• 한국한의학연구원논문집
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• 제9권2호
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• pp.17-27
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• 2003

Eumyang-ohaeng[陰陽五行-Eumyang and five phases], as a standing rule that establishes the theory of Oriental medicine and origin of the oriental philosophy, it provides the perspective of the oriental medicine's outlook of the world. Without knowing the Eumyang-ohaeng, we cannot discuss Oriental medicine, nor can we understand the oriental way of thinking. Time and Space is what the human being created in order to explain the existence and change of matters. There is a common denominator between this universal concept of time and space and the theory of Eumyang-ohaeng. Consequently this paper investigates how characteristics of Eumyang-ohaeng and that of time and space matches Eumyang represents all matter and its characteristic, by comparison with each other space, and Ohaeng shows the change of matter with time gradually and sequancely. But this separation is only a separation by words, they really melt into one like two sides of a coin is actually just one coin. After all the theory of Eumyang-ohaeng is a theory that leads us to realize time and space, matter and power are all just one. So consequently, despite the difference in mass or size or longevity of matters, Eumyang-ohaeng pulls all matter into one body. It's why Eumyang-ohaeng is defined as the unified theory of time and space.

• 태양에너지
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• 제17권1호
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• pp.35-46
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• 1997

In this study comparison of experiment results with the computed results of linear theory and nonlinear theory using singularity method was obtainable. Specially singularity points like sources and vortexes on hydrofoil and freestreamline were distributed to analyze two dimensional flow field of supercavitating cascade using nonlinear theory, and governing equations of flow field were derived and hydraulic characteristics of cascade were calculated by numerical analysis of the governing equations. The results compared linear theory and nonlinear theory with the experiment results of the study are as follows: The tolerances of nonlinear theory were larger than those of linear theory in case of ${\alpha}<10^{\circ}$. Moreover the computational range of attack angles could be expanded from ${\alpha}=10^{\circ}$ to ${\alpha}=25^{\circ}$, the flow field of supercavitating cascade could be analyzed in the condition which the wake thickness and the length of cavity are a variable. The shapes of cavity were changed sensitively according to various variable such as attack angles, pitches and wake thickness, and the pressure distribution of hydrofoil surface was identical almost disregarding wake thickness but changed largely according to attack angle and the length of cavity. Lift coefficient and drag coefficient were reduced according to increasing of wake thickness but the influences of wake thickness were very little in the situation of small pitch and long cavity.

• Structural Engineering and Mechanics
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• 제75권4호
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• pp.487-496
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• 2020

Most of the previous works on numerical analysis of galloping of transmission lines are generally based on the quasisteady theory. However, some wind tunnel tests of the rectangular section or hangers of suspension bridges have shown that the galloping phenomenon has a strong unsteady characteristic and the test results are quite different from the quasi-steady calculation results. Therefore, it is necessary to check the applicability of the quasi-static theory in galloping analysis of the ice-covered transmission line. Although some limited unsteady simulation researches have been conducted on the variation of parameters such as aerodynamic damping, aerodynamic coefficients with wind speed or wind attack angle, there is a need to investigate the numerical simulation of unsteady galloping of two-dimensional iced transmission line with comparison to wind tunnel test results. In this paper, it is proposed to conduct a two dimensional (2-D) unsteady numerical analysis of ice-covered transmission line galloping. First, wind tunnel tests of a typical crescent-shapes iced conductor are conducted firstly to check the subsequent quasisteady and unsteady numerical analysis results. Then, a numerical simulation model consistent with the aeroelastic model in the wind tunnel test is established. The weak coupling methodology is used to consider the fluid-structure interaction in investigating a two-dimension numerical simulation of unsteady galloping of the iced conductor. First, the flow field is simulated to obtain the pressure and velocity distribution of the flow field. The fluid action on the iced conduct at the coupling interface is treated as an external load to the conductor. Then, the movement of the conduct is analyzed separately. The software ANSYS FLUENT is employed and redeveloped to numerically analyze the model responses based on fluid-structure interaction theory. The numerical simulation results of unsteady galloping of the iced conduct are compared with the measured responses of wind tunnel tests and the numerical results by the conventional quasi-steady theory, respectively.

• Wind and Structures
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• 제32권2호
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• pp.81-87
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• 2021

The aim of the current study is to compare the performance of large 2 MW and 3 MW wind turbines operating on existing onshore wind farms using Blade Element Momentum (BEM) theory and Angular Momentum (AM) theory and illustrate the performance characteristic curves of the turbines as a function of wind speed (U∞). To achieve this, the measurement data obtained from two different Wind Energy Power Plants (WEPPs) located in the Hatay region of Turkey was used. Two different horizontal-axis wind turbines with capacities of 2 MW and 3 MW were selected for evaluation and comparison. The hub-height wind speed (UD), turbine power output (P), atmospheric air temperature (Tatm) and turbine rotational speed (Ω) data were used in the evaluation of the turbine performance characteristics. Curves of turbine power output (P), axial flow induction factor (a), turbine rotational speed (Ω), turbine power coefficient (CP), blade tip speed ratio (λ), thrust force coefficient (CT) and thrust force (T) as a function of U∞ were obtained for the 2 MW and 3 MW wind turbines and these characteristic curves were compared. Results revealed that, for the same wind speed conditions, the higher-capacity wind turbine (3 MW) was operating at higher turbine power coefficient rates, while rotating at lower rotational speed ratios than the lower-capacity wind turbine (2 MW).

• 태양에너지
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• 제14권2호
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• pp.29-37
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• 1994

본 연구에서는 다공성 물질을 이용한 공기용 태양열 집열기에서 사용될 수 있는 유리덮개 및 다공성 매질의 파장에 따른 투과율(transmittance)을 UV-visible spectrophotometer및 FT-IR spectrometer을 이용하여 측정하였다. 유리의 경우에는 전자기 이론으로 유도된 투과율과 실험적 투과율을 비교하여 유리의 복소굴절율(complex refractive index)을 구하였다. 또한 분산이론(classical dispersion theory)으로부터 구한 이론적 복소굴절율과 비교하였다. 다공성 매질은 15 메쉬의 stainless steel wire screen을 여러 겹으로 겹쳐 이에 대한 투과율을 측정하였다. 그리고 two-flux모델을 사용하여 흡수계수(absorption coefficient) 및 후면산란 계수(backscattering coefficient)를 구하였다.

• 천문학회보
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• 제41권1호
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• pp.47.2-47.2
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• 2016

The protons and helium ions in the solar wind are observed to possess anisotropic temperature profiles. The anisotropy appears to be limited by various marginal instability conditions. One of the efficient methods to investigate the global dynamics and distribution of various temperature anisotropies in the large-scale solar wind models may be that based upon the macroscopic quasi-linear approach. The present paper investigates the proton and helium ion anisotropy instabilities on the basis of comparison between the quasi-linear theory versus particle-in-cell simulation. It is found that the overall dynamical development of the particle temperatures is quite accurately reproduced by the macroscopic quasi-linear scheme. The wave energy development in time, however, shows somewhat less restrictive comparisons, indicating that while the quasi-linear method is acceptable for the particle dynamics, the wave analysis probably requires higher-order physics, such as wave-wave coupling or nonlinear wave-particle interaction. We carried out comparative studies of proton firehose instability, aperiodic ordinary mode instability, and helium ion anisotropy instability. It was found that the agreement between QL theory and PIC simulation is rather good. It means that the quasilinear approximation enjoys only a limited range of validity, especially for the wave dynamics and for the relatively high-beta regime.

• 대한한의학원전학회지
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• 제33권1호
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• pp.1-16
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• 2020

Objectives : This study aims to organize the genealogy of the Ministerial Fire Theory in relation to Wangbing's Dragon Fire discourse through examining how Wang's Dragon Fire content first mentioned in the annotation of 『Suwen』 was included into the discourse of the Ministerial Fire Theory in explaining the concept of Ministerial Fire and its therapeutic application. Methods :First to examine the inclusion and application of the Dragon Fire concept into the Ministerial Fire Theory, Zhudanxi's theory and critiques on him were studied. Next the concept of Dragon Fire within the Ministerial Fire Theory was analyzed, followed by comparison between generations of doctors's therapeutic application of Ministerial Fire and Wangbing's Dragon Fire application. Conclusions & Results : Wangbing's dragon fire concept held an important position in discussing its characteristic as fire within water, which was adopted and differentiated by later doctors in aspects of pathology, deficiency and excessiveness, influenced by various theoretical elements of later periods. In the midst of expansion of the concept from combination of dragon fire and ministerial fire, the therapeutic aspect of it was maintained from Wangbing's original mentioning. This tendency manifested in either awkward combination of Wang's therapeutic methods and the new theory or modification of Wangbing's methods.