• Title/Summary/Keyword: natural constants

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MATHEMATICAL CONSTANTS ASSOCIATED WITH THE MULTIPLE GAMMA FUNCTIONS

  • Jung, Myung-Ho;Cho, Young-Joon;Choi, June-Sang
    • East Asian mathematical journal
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    • v.21 no.1
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    • pp.77-103
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    • 2005
  • The theory of multiple Gamma functions was studied in about 1900 and has, recently, been revived in the study of determinants of Laplacians. There is a class of mathematical constants involved naturally in the multiple Gamma functions. Here we summarize those mathematical constants associated with the Gamma and multiple Gamma functions and will show how they are involved, if possible.

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A Study on Optimization of Diesel Combustion in condition of Premixed Natural gas (천연가스 예혼합 분위기 내 디젤 연소의 최적화에 관한 연구)

  • Suh, Hyunuk;Jeon, Chunghwan
    • 한국연소학회:학술대회논문집
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    • 2014.11a
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    • pp.141-142
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    • 2014
  • This numerical study was carried out to optimize dual fuel combustion on natural gas-diesel in static chamber. Spray experiments conducted under conditions of premixed methan 0%, 5% and 10%. In the results, penetration decreases when premixed methane is increasing. Constants of numerical models were acquired from results of spray experiments to enhance accuracy of numerical study. And dual fuel engine simulation was implemented by using AVL-FIRE with acquired constants.

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Kinetics of Hydrogen-Deuterium Exchange of 8-CH Groups in Adenosine 5$^\prime$-Monophosphate and Guanosine 5$^\prime$-Monophosphate by Laser Raman Spectroscopy

  • Kim, Sang-Kyu;Kim, Myung-Soo;Suh, Se-Won
    • Bulletin of the Korean Chemical Society
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    • v.6 no.5
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    • pp.270-272
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    • 1985
  • The rate constants of the hydrogen-deuterium exchange of 8-CH groups in 5'-rAMP and 5'-GMP were measured by laser Raman spectroscopy. The Arrhenius activation energies calculated from the rate constants measured as a function of temperature were similar for both compounds. However, the effects of pD on exchange rate constants were different for the two compounds. Our kinetic data support the exchange reaction mechanism involving an ylide type intermediate.

THREE GEOMETRIC CONSTANTS FOR MORREY SPACES

  • Gunawan, Hendra;Kikianty, Eder;Sawano, Yoshihiro;Schwanke, Christopher
    • Bulletin of the Korean Mathematical Society
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    • v.56 no.6
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    • pp.1569-1575
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    • 2019
  • In this paper we calculate three geometric constants, namely the von Neumann-Jordan constant, the James constant, and the Dunkl-Williams constant, for Morrey spaces and discrete Morrey spaces. These constants measure uniformly nonsquareness of the associated spaces. We obtain that the three constants are the same as those for $L^1$ and $L^{\infty}$ spaces.

Paper Ionophoretic Technique in the Study of Mixed Complexes

  • Tewari, Brij Bhushan
    • Bulletin of the Korean Chemical Society
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    • v.23 no.5
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    • pp.705-707
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    • 2002
  • Stability constants of complexes of aluminium(III) and thorium(IV) with methionine and cysteine have been determined by modified paper electrophoretic technique at $\mu$ = 0.1 M. The proportion of ionic species of methionine and cysteine were varied by changing pH of background electrolyte. The stability constants of the complexes metal-methionine-cysteine have been found to be 4.31 ± 0.12 and 5.40 ± 0.19 (log K values) for $Al^{3+}\;and\;Th^{4+} $ complexes, at temperature 35 ${^{\circ}C}$, respectively.

Experimental Determinations of Elastic Constants Composite Materials, Carbon-epoxy and Graphite-epoxy, Using Two Dynamic Vibratory Techniques (두 가지 동적 진동실험을 통한 Carbon-epoxy와 Graphite-Epoxy복합재료의 동적 탄성계수 측정)

  • Lee, D.H.;Bahk, S.M.;Park, M.K.
    • Proceedings of the KSME Conference
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    • 2001.11a
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    • pp.596-602
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    • 2001
  • Structures in current use are required of weight reduction and strength in many instances. This naturally necessitates frequent applications of composite materials in many areas. Elastic constants are one of key parameters in determining design guidelines for the specific applications of particular materials. In this research two vibratory techniques (acoustic resonance method and impulse technique)are utilized to evaluate elastic constants. Both techniques are suitable for the measurements of dynamic elastic constants. The Impulse technique provides a quick method for the measurement while the acoustic resonance method produces the values of elastic constants which agree better with theoretical values.

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Solvolysis Reaction Kinetics, Rates and Mechanism for Phenyl N-Phenyl Phosphoramidochloridate

  • Choi, Hojune;Yang, Kiyull;Koh, Han Joong;Koo, In Sun
    • Bulletin of the Korean Chemical Society
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    • v.35 no.8
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    • pp.2465-2470
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    • 2014
  • The rate constants of solvolysis of phenyl N-phenyl phosphoramidochloridate (PhNHPO(Cl)OPh, Target Compound-TC1) have been determined by a conductivity method. The solvolysis rate constants of TC1 are well correlated with the extended Grunwald-Winstein equation, using the $N_T$ solvent nucleophilicity scale and YCl solvent ionizing scale, and sensitivity values of $0.85{\pm}0.14$ and $0.53{\pm}0.04$ for l and m, respectively. These l and m values were similar to those obtained previously for the complex chemical substances dimethyl thiophosphorochloridate; N,N,N',N'-tetramethyldiamidophosphorochloridate; 2-phenyl-2-ketoethyl tosylate; diphenyl thiophosphinyl chloride; and 9-fluorenyl chloroformate. As with the five previously studied solvolyses, an $S_N2$ pathway is proposed for the solvolyses of TC1. For four representative solvents, the rate constants were measured at several temperatures, and activation parameters (${\Delta}H^{\neq}$ and ${\Delta}S^{\neq}$) were estimated. These activation parameters are also in line with the values expected for an $S_N2$ reaction.

Fluid-conveying piezoelectric nanosensor: Nonclassical effects on vibration-stability analysis

  • Kachapi, Sayyid H. Hashemi
    • Structural Engineering and Mechanics
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    • v.76 no.5
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    • pp.619-629
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    • 2020
  • In current study, surface/interface effects for pull-in voltage and viscous fluid velocity effects on dimensionless natural frequency (DNF) of fluid-conveying piezoelectric nanosensor (FCPENS) subjected to direct electrostatic voltage DC with nonlinear excitation, harmonic force and also viscoelastic foundation (visco-pasternak medium and structural damping) are investigated using Gurtin-Murdoch surface/interface (GMSIT) theory. For this analysis, Hamilton's principles, the assumed mode method combined with Lagrange-Euler's are used for the governing equations and boundary conditions. The effects of surface/interface parameters of FCPENS such as Lame's constants (λI,S, μI,S), residual stress (τ0I,S), piezoelectric constants (e31psk,e32psk) and mass density (ρI,S) are considered for analysis of dimensionless natural frequency respect to viscous fluid velocity u̅f and pull-in voltage V̅DC.

EFFECT OF CARBONATE ON THE SOLUBILITY OF NEPTUNIUM IN NATURAL GRANITIC GROUNDWATER

  • Kim, B.Y.;Oh, J.Y.;Baik, M.H.;Yun, J.I.
    • Nuclear Engineering and Technology
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    • v.42 no.5
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    • pp.552-561
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    • 2010
  • This study investigates the solubility of neptunium (Np) in the deep natural groundwater of the Korea Atomic Energy Research Institute Underground Research Tunnel (KURT). According to a Pourbaix diagram (pH-$E_h$ diagram) that was calculated using the geochemical modeling program PHREEQC 2.0, the redox potential and the carbonate ion concentration both control the solubility of neptunium. The carbonate effect becomes pronounced when the total carbonate concentration is higher than $1.5\;{\times}\;10^{-2}$ M at $E_h$ = -200 mV and the pH value is 10. Given the assumption that the solubility-limiting stable solid phase is $Np(OH)_4(am)$ under the reducing condition relevant to KURT, the soluble neptunium concentrations were in the range of $1\;{\times}\;10^{-9}$ M to $3\;{\times}\;10^{-9}$ M under natural groundwater conditions. However, the solubility of neptunium, which was calculated with the formation constants of neptunium complexes selected in an OECD-NEA TDB review, strongly deviates from the value measured in natural groundwater. Thus, it is highly recommended that a prediction of neptunium solubility is based on the formation constants of ternary Np(IV) hydroxo-carbonato complexes, even though the presence of those complexes is deficient in terms of the characterization of neptunium species. Based on a comparison of the measurements and calculations of geochemical modeling, the formation constants for the "upper limit" of the Np(IV) hydroxo-carbonato complexes, namely $Np(OH)_y(CO_3)_z^{4-y-2z}$, were appraised as follows: log $K^{\circ}_{122}\;=\;-3.0{\pm}0.5$ for $Np(OH)_2(CO_3)_2^{2-}$, log $K^{\circ}_{131}\;=\;-5.0{\pm}0.5$ for $Np(OH)_3(CO_3)^-$, and log $K^{\circ}_{141}\;=\;-6.0{\pm}0.5$ for $Np(OH)_4(CO_3)^{2-}$.