• Title/Summary/Keyword: Radial Distribution Function

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A Study on YHB RDF via Density Dependent Pressure Calculation of Ethene Gas (Ethene 기체의 밀도변화에 따른 압력 계산에 의한 YHB 동경분포함수에 대한 연구)

  • Yoon, Jong Ho;Kim, Hae Won
    • Applied Chemistry for Engineering
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    • v.9 no.4
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    • pp.561-564
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    • 1998
  • The radial distribution functions of a linear spheroidal type gas molecule $C_2H_4$ were calculated by using the Stockmayer molecular molel, which assumed the $C_2H_4$ molecule as simple quadrupolar molecule. To examine the validity of the calculated radial distribution of $C_2H_4$ gas, the density dependent pressures of $C_2H_4$ gas at several temperatures were calculated and compared with literarily known experimental pressure data of $C_2H_4$ gas. The temperatures examined was 50, 100 and $150^{\circ}C$ and the densities were up to $0.02/{\AA}^3$ (maximum pressure = 1500 atm). The radial distribution function expression used was derived by Yoon, Hacura, and Baglin (YHB) with Baker and Henderson's perturbation theory. The calculated results by a computer showed that the $C_2H_4$ pressures calculated agreed well with the experimental values within ${\pm}5%$ of error range. This indicated that the YHB radial distribution function expression is good enough to obtain various physical quantities sensitive to density such as pressure with resonable accuracy.

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On the Radial Basis Function Networks with the Basis Function of q-Normal Distribution

  • Eccyuya, Kotaro;Tanaka, Masaru
    • Proceedings of the IEEK Conference
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    • 2002.07a
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    • pp.26-29
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    • 2002
  • Radial Basis Function (RBF) networks is known as efficient method in classification problems and function approximation. The basis function of RBF networks is usual adopted normal distribution like the Gaussian function. The output of the Gaussian function has the maximum at the center and decrease as increase the distance from the center. For learning of neural network, the method treating the limited area of input space is sometimes more useful than the method treating the whole of input space. The q-normal distribution is the set of probability density function include the Gaussian function. In this paper, we introduce the RBF networks with the basis function of q-normal distribution and actually approximate a function using the RBF networks.

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A study on the temperature distribution measurement of the high pressure mercury lamp (고압 수은등의 온도분포 측정에 대한 연구)

  • 손승현;김상용;김창섭;지철근
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 1990.10a
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    • pp.35-40
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    • 1990
  • Temperature distribution of high pressure mercury lamp has been mesured as a function of time using spectroscopic method. Sampling signal which is synchronized by lamp voltage was used to mesure temporal line intensity at each radius. To obtain radial temprature distribution, the mesured intensity was transformed into radial line intensity by Abel's formula. Absolute temperature profile was calculater from relative intensities of spectral lines as a function of line and tube radius. The temperature profile is very similar to the electrical tube current profile.

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Characterization of Atomic Structure in Rapidly Solidified Amorphous Silicon (급냉응고된 비정질 실리콘 분말의 원자구조에 관한 연구)

  • Kim, Yeon-Ok
    • Korean Journal of Materials Research
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    • v.4 no.6
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    • pp.644-650
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    • 1994
  • The submicron powders of high-purity silicon have been produced by Electrohydrodynamic Atomization. Field-emission scanning transmission electron microscopy(STEM) is used to determine the microstructure and solidification phase. .Then it is found that the droplets less than 60nm diameter are solidified as the amorphous phase. A useful and accessible characterization of atomic arrangements in amorphous solids can be given in terms of a radial distribution function. According to experimental determinations of the radial distribution function for amorphous silicon, its similarity to the crystalline structure at small radial distances indicates that the basic tetrahedral arrangement found in the diamond cubic structure of silicon must be maintained in the amorphous structure.

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Optimal Capacitor Placement and Control using Genetic Algorithms in Unbalanced Distribution Systems. (불평형 배전계통에 있어서 유전알고리즘을 이용한 커패시터의 적정 배치 및 제어)

  • Kim, Kyu-Ho;You, Seok-Ku
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.48 no.7
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    • pp.839-846
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    • 1999
  • This paper presents an efficient algorithm for determining the location, size and number of capacitors in unbalanced radial distribution system. The objective function formulated consists of two terms: cost for energy loss and cost related to capacitor purchase and capacitor installation. The cost function associated with capacitor placement is considered as step function due to banks of standard discrete capacities. Genetic algorithms(GA) are used to obtain the population is derived. The strings in each population consist of the bus number index and size of capacitors to be installed. In order to determine the number of capacitor placement, the length mutation operator is used. Its efficiency is proved through the application in unbalanced radial distribution systems made of 10 buses with 9 distribution lines and 25 buses with 24 distribution lines.

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Calculation of the Entropies and Chemical Potentials of Hard-Sphere Solutes Solvated in Hard-Sphere Solids Using the Radial Free-Space Distribution Function

  • 윤병집
    • Bulletin of the Korean Chemical Society
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    • v.20 no.10
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    • pp.1209-1212
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    • 1999
  • The entropies and chemical potentials of hard-sphere solutes solvated in hard-sphere solids were calculated by Monte Carlo method using the radial free-space distribution function. This method is based on calculating the entropy by comparing the free volume of a molecule with that of an ideal gas, and is applicable even when the size of solute is very large and the solvent is a solid. When the diameter of hard-sphere solute is small the solute molecule behaves as like as a fluid in solid structures, but when the diameter of solute becomes large, a fluid-to-solid phase transition takes place. The fluid-to-solid phase transition occurs at the region of the smaller size of solute with the more increase of solvent density. The least square fit values of analytical form of the radial free-space distribution functions of solute molecules are presented for future uses.

Prediction of Hindered Settling Velocity of Bidisperse Suspensions (이중 입도 분포를 가진 현탁액의 침강 속도 예측)

  • Koo, Sangkyun
    • Applied Chemistry for Engineering
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    • v.19 no.6
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    • pp.609-616
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    • 2008
  • The present study is concerned with a simple numerical method for estimating the hindered settling velocity of noncolloidal suspensions with bidisperse size distribution of particles. The method is based on an effective-medium theory which uses the conditional ensemble averages for describing the velocity fields or other physical quantities of interest in the suspension system with the particles randomly placed. The effective-medium theory originally developed by Acrivos and Chang[1] for monodisperse suspensions is modified for the bidisperse case. Using the radial distribution functions and stream functions the hindered settling velocity of the suspended particles is calculated numerically. The predictions by the present method are compared with the previous experimental results by Davis and Birdsell[2] and Cheung et al.[3]. It is shown that the estimations by the effective-medium model of the present study reasonably agree with the experimental results.

Optimal Capacitor Placement and Operation for Loss reduction and Improvement of Voltage Profile in Radial Distribution Systems (방사상 배전계통의 손실감소 및 전압보상을 위한 커패시터 최적 배치 및 운용)

  • Kim, Tae-Kyun;Baek, Young-Ki;Kim, Kyu-Ho;You, Seok-Ku
    • Proceedings of the KIEE Conference
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    • 1997.07c
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    • pp.1009-1011
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    • 1997
  • This paper presents an optimization method which determines locations and size of capacitors simultaneously while minimizing power losses and improving voltage profile in radial distribution systems. Especially, the cost function associated with capacitor placement is considered as step function due to banks of standard discrete capacities. Genetic algorithms(GA) are used to obtain efficiently the solution of the cost function associated with capacitors which is non-continuous and non-differentiable function. The strings in GA consist of the node number index and size of capacitors to be installed. The length mutation operator, which is able to change the length of strings in each generation, is used. The proposed method which determines locations and size of capacitors simultaneously can reduce power losses and improve' voltage profile with capacitors of minimum size. Its efficiency is proved through the application in radial distribution systems.

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The Radial Distribution Functions of the Scaled OSS2 Water

  • Lee, Song Hi
    • Journal of the Korean Chemical Society
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    • v.56 no.6
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    • pp.669-672
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    • 2012
  • Classical molecular dynamics (MD) simulations using a scaled OSS2 potential originally derived from ab initio calculations are used to study the radial distribution functions of water. The original OSS2 water potential is shown to represent a glassy or an ice at ambient temperature, but the diffusion coefficient increases on increasing the temperature of the system or decreasing the density. This suggests scaling the OSS2 potential. The O-O, O-H, and H-H radial distribution functions and the corresponding coordination numbers for the scaled OSS2 potential, obtained by MD simulation, are in good agreement with the experiment results and calculations for the SPC/E water potential over a range of temperatures.

A Development of Markov Chain Monte Carlo History Matching Technique for Subsurface Characterization (지하 불균질 예측 향상을 위한 마르코프 체인 몬테 카를로 히스토리 매칭 기법 개발)

  • Jeong, Jina;Park, Eungyu
    • Journal of Soil and Groundwater Environment
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    • v.20 no.3
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    • pp.51-64
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    • 2015
  • In the present study, we develop two history matching techniques based on Markov chain Monte Carlo method where radial basis function and Gaussian distribution generated by unconditional geostatistical simulation are employed as the random walk transition kernels. The Bayesian inverse methods for aquifer characterization as the developed models can be effectively applied to the condition even when the targeted information such as hydraulic conductivity is absent and there are transient hydraulic head records due to imposed stress at observation wells. The model which uses unconditional simulation as random walk transition kernel has advantage in that spatial statistics can be directly associated with the predictions. The model using radial basis function network shares the same advantages as the model with unconditional simulation, yet the radial basis function network based the model does not require external geostatistical techniques. Also, by employing radial basis function as transition kernel, multi-scale nested structures can be rigorously addressed. In the validations of the developed models, the overall predictabilities of both models are sound by showing high correlation coefficient between the reference and the predicted. In terms of the model performance, the model with radial basis function network has higher error reduction rate and computational efficiency than with unconditional geostatistical simulation.