• 동력기계공학회지
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• 제7권3호
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• pp.69-73
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• 2003

In this paper, the relation between displacement of piezoelectric disk and electric field was proposed. From Navier-Stokes equation and Reynold's equation, the relation between flow and gap of plate was determined. This models were further verified by experiments. Based on theoretical study and experimental verification, the proposed model between flow rate and voltage can be used in the design of mass flow controller in gas supplying system.

• 한국세라믹학회지
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• 제24권1호
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• pp.1-8
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• 1987

The validity of Alyavdin-Chujyo's Equation was re-examined over the broader milling conditions that those previously examined. Ordinary ball mill grinding with a laboratory scale batch mill (133mmø×144mm length) were selected as the grinding methods. The results show that in ball milling the Alyavdin-Chunjyo's Equation can be applicable over wide grinding time and size range with few exceptions. The validity of which are examined and discussed. The theoretical consideration of the relation between Alyavdin-Chujyo's Equation and size distributiion equation, such as Rosin-Rammler's law, was tried, and it is found that, under the condition of alyardin-Chujyo's relation, the Rosin-Rammler size distribution law can hold.

• 한국세라믹학회지
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• 제24권1호
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• pp.47-55
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• 1987

The purpose of this work is to establish the basic calibration data for the efficiency of grinding by investigating the Bond's Work Index employing Korean Kaolin as a reference mateial with the laboratory-scale ball mill. A small ordinary ball mill has a dimension of 133 inside diameter and 144mm long. The analysis of the experimental results in this work sets up a equivalent calibration method with the laboratory-scale ball mill to those with special mill. The theoretical expression, derived from the rate equation proposed by Miwa, is obtained to anticipitate the stable revolution number for the next grinding cycle. The proposed equation is more systematic and acurate than lshihara's empirical equation is more systematic and acurate than lshihara's empirical equation for the measurement of gindability of a ball mill.

• EDISON SW 활용 경진대회 논문집
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• 제6회(2016년)
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• pp.101-105
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• 2016

Prandtl's Lifting-line theory is the classical theory of calculating aerodynamic properties. Though it is classical method, it predicts the aerodynamic properties well. By lifting-line theory, high aspect ratio is critical factor to decrease induced drag. And 'elliptic-similar' wing also makes the minimum induced drag. But due to the problem of manufacturing, tapered wing is preferred and have been utilized. In this Paper, by using Edison CFD, verifying the classical lifting-line theory. To consider induced drag only, using Euler equation as governing equation instead of full Navier-Stokes equation. Refer to the theory, optimum taper ratio which makes the minimum induced drag is 0.3. Utilizing the CFD results, plotting oswald factor over various taper ratio and investigating whether the consequences are valid or not. As a result, solving Euler equation by EDISON CFD cannot guarantee the theoretical values because it is hard to set the proper grid to solve. Results are divided into two cases. One is the values are decreased gradually and another seems to following tendency, but values are all negative number.

• Bulletin of the Korean Chemical Society
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• 제22권7호
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• pp.732-738
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• 2001

The cross second-derivative of the activation energy,${\theta}$G${\neq}$ , with respect to the two component thermodynamic barriers, ${\theta}$G˚X and ${\theta}$G$^{\circ}C$Y, can be given in terms of a cross-interaction constant (CIC), $\betaXY(\rhoXY)$, and also in terms of the intrinsic barrier,${\theta}$G${\neq}$ , with a simple relationship between the two: $\betaXY$ = $-1}(6${\theta}$G${\neq}$).$ This equation shows that the distance between the two reactants in the adduct (TS, intermediate, or product) is inversely related to the intrinsic barrier. An important corollary is that the Ritchie N+ equation holds (for which $\betaXY$ = 0) for the reactions with high intrinsic barrier. Various experimental and theoretical examples are presented to show the validity of the relationship, and the mechanistic implications are discussed.

• Nuclear Engineering and Technology
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• 제54권9호
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• pp.3181-3204
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• 2022

The variational nodal method for solving the neutron transport equation has evolved over 40 years. Based on a functional form of the Boltzmann neutron transport equation, the method now comprises a complete set of variants that can be employed for different problems. This paper presents an extensive review of the development of the variational nodal method. The emphasis is on summarizing the whole theoretical system rather than validating the methodologies. The paper covers the variational nodal formulation of the Boltzmann neutron transport equation, the Ritz procedure for various application purposes, the derivation of boundary conditions, the extension for adjoint and perturbation calculations, and treatments for anisotropic scattering sources. Acceleration approaches for constructing response matrices and solving the resulting system of algebraic equations are also presented.

• Earthquakes and Structures
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• 제23권2호
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• pp.169-181
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• 2022

To research the dynamic response of the high-rise structure under the rocking ground motion, which we believed that the effect cannot be ignored, especially accompanied by vertical ground motion. Theoretical analysis and shaking table seismic simulation tests were used to study the response of a high-rise structure to excitation of a H-V-R ground motion that included horizontal, vertical, and rocking components. The use of a wavelet analysis filtering technique to extract the rocking component from data for the primary horizontal component in the first part, based on the principle of horizontal pendulum seismogram and the use of a wavelet analysis filtering technique. The dynamic equation of motion for a high-rise structure under H-V-R ground motion was developed in the second part, with extra P-△ effect due to ground rocking displacement was included in the external load excitation terms of the equation of motion, and the influence of the vertical component on the high-rise structure P-△ effect was also included. Shaking table tests were performed for H-V-R ground motion using a scale model of a high-rise TV tower structure in the third part, while the results of the shaking table tests and theoretical calculation were compared in the last part, and the following conclusions were made. The results of the shaking table test were consistent with the theoretical calculation results, which verified the accuracy of the theoretical analysis. The rocking component of ground motion significantly increased the displacement of the structure and caused an asymmetric displacement of the structure. Thus, the seismic design of an engineering structure should consider the additional P-△ effect due to the rocking component. Moreover, introducing the vertical component caused the geometric stiffness of the structure to change with time, and the influence of the rocking component on the structure was amplified due to this effect.

• 한국수자원학회논문집
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• 제33권2호
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• pp.195-205
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• 2000

도달시간 산정에 있어 고려되어야 할 요소에는 유역형상과 흐름상태, 유출특성 등이 있다. 한편 Singh(1976)은 지표면흐름을 Kinematic Wave 이론으로 해석하였으며 유역형상을 평면형상과 수렴형상, 발산형상으로 분류하여 유역형상에 따른 도달시간 산정식을 제시하였다. 본 논문에서는 Singh이 제시한 평면형상에서의 도달시간 산정식에 기초하여 불투수 지표면 유출에서의 도달시간 산정을 다루었다. 이를 위한 이론식 유도는 흐름을 개수로 흐름(층류, 완난류, 전난류)으로 파악하여 수행하였고 각 개수로 흐름상태에 대한 이론식을 제시하였다. 또한 강우강도를 주요 인자로 고려하여 재현기간별 강우강도를 포함한 근사식 즉 복합형 도달시간 산정식을 개발하였다.

• 대한토목학회논문집
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• 제4권2호
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• pp.77-88
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• 1984

이미 유도제안(誘導提案)된 수동(受動)줄말뚝에 작용(作用)하는 측방토압(側方土壓)의 산정이론식(算定理論式)을 단일(單一)말뚝에까지 발전(發展)시킴과 동시(同時)에 본산정이론식(本算定理論式)에 포함되어 있는 지반(地盤)과 말뚝에 관한 요소(要素)들을 조사(調査)하여 사용(使用)하기 간편한 형태(形態)의 식(式)으로 정리(整理)하고자 한다. 즉, 본연구(本硏究)를 통하여 수동(受動)말뚝의 측방토압산정이론식(側方土壓算定理論式)은 측방토압계수(側方土壓係數) $K_{p1}$ 및 $K_{p2}$를 도입(導入)함에 의하여 점착력(粘着力) c와 지반변형방향(地盤變形方向)에 대항하여 말뚝열(列) 후면(後面)에 작용(作用)하는 수평토압(水平土壓) ${\sigma}_H$의 항(項)으로 구성(構成)된 간단(簡單)한 선형식(線形式)으로 정리제안(整理提案)된다. 그 밖에도 본이론식(本理論式)을 현장(現場)에 적용(適用)할 경우 수평토압(水平土壓) ${\sigma}_H$로는 주동토압(主動土壓)을 채용(採用)함이 합리적(合理的)이라는 점에 대한 타당성(妥當性)이 이론치(理論値)와 실측치(實測値)의 비교검토(比較檢討)를 통하여 입증(立證)되어 진다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
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• pp.547-553
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• 2017

Differential Scanning Calorimetry(DSC)를 이용하여 파이로점화장치에 사용되는 세 가지 고에너지 물질의 열분석 실험을 수행하였다. DSC 실험 데이터를 이용하여 고에너지 물질의 반응속도식을 추출해내는 이론적 방법을 제안하고 반응속도식 추출을 수행하였다. DSC 실험 결과는 Friedman 등전환법으로 분석되었다. 질량분율에 따른 활성화에너지와 빈도인자를 추출해 내어 반응속도식을 완성하였다. 추출된 반응속도식은 고에너지 물질의 화학반응과정을 몇 단계의 주요단계로 가정하는 형태가 아닌 전체 화학 반응 과정을 나타내는 형태를 갖는다. 이는 기존의 열분석 실험을 통해 추출되는 화학반응속도식 형태에 비해 이론적 측면과 정확성 측면에서 상당한 장점을 갖는다. 도출된 반응속도식을 이용하여 실제 추진기관에 운용되는 세 가지 고에너지 물질의 성능변화를 20년에 대하여 예측하였다.