• Title/Summary/Keyword: Elemental theory

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A Comparison of Three Theories of Firm Boundaries (기업경계에 관한 세 이론의 비교)

  • Chung, Hoe-Sang
    • Asia-Pacific Journal of Business
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    • v.12 no.3
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    • pp.87-99
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    • 2021
  • Purpose - In this study, I attempt to clarify three theories of firm boundaries (vertical integration): the principal-agent theory, transaction cost theory, and property rights theory. Although these theories have been widely cited and much discussed, it has been found that understanding the commonalities and distinctions of these seemingly familiar theories is difficult. Design/methodology/approach - I present the three theories about the decisions that firms make concerning their boundaries. Then, I compare elemental versions of the theories of the firm. Findings - Comparing the ingredients of the elemental property rights and principal-agent theories shows that they provide a unified account of the costs and benefits of vertical integration. However, the property rights theory in no sense formalizes the transaction cost theory. Research implications or Originality - Clarifying the three theories of the firm can help to construct empirical models and interpret its results.

Analysis between elemental image size and object locations in the pickup using periodically-distributed lenslets and enhancement of computational integral imaging (주기적으로 배치된 렌즈 배열 픽업에서의 요소 영상 크기와 3차원 물체 위치와의 해석과 컴퓨터 집적 영상 복원 화질 개선 방법)

  • Yoo, Hoon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.15 no.5
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    • pp.1171-1176
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    • 2011
  • This paper describes an analysis on the relationship between elemental image size and object locations in the computational integral imaging reconstruction and in the pickup using a periodically-distributed lenslet array. A sparse sampling effect arises from a periodically-distributed lenslet array in the pickup of 3D objects. The relationship between elemental image size and object location is also reported. Based on the analysis, a method to eliminate the sparse sampling is proposed. To show the effectiveness of the proposed method, experimental results are carried out. It turns out that the theory works.

Borehole Elemental Concentration Logs: Theory, Current Trends and Next Level (암석구성성분검층: 원리, 연구동향 및 향후 과제)

  • Shin, Jehyun;Hwang, Seho
    • Geophysics and Geophysical Exploration
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    • v.22 no.3
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    • pp.149-159
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    • 2019
  • Borehole elemental concentration logging, measuring neutron-induced gamma rays by inelastic scattering and neutron capture interactions between neutron and formation, delivers concentrations of the most common elements found in the minerals and fluids of subsurface formation. X-ray diffraction and X-ray fluorescence analysis from core samples are traditionally used to understand formation composition and mineralogy, but it represents only part of formations. Additionally, it is difficult to obtain elemental analysis over the whole intervals because of poor core recovery zones such as fractures or sand layers mainly responsible for groundwater flow. The development of borehole technique for in situ elemental analysis plays a key role in assessing subsurface environment. Although this technology has advanced consistently starting from conventional and unconventional resources evaluation, it has been considered as exclusive techniques of some major service company. As regards domestic research and development, it has still remained an unexplored field because of some barriers such as the deficiency of detailed information on tools and calibration facility for chemistry and mineralogy database. This article reviews the basic theory of spectroscopy measurements, system configuration, calibration facility, and current status. In addition, this article introduces the domestic researches and self-development status on borehole elemental concentration tools.

Adsorption Characteristics of Elemental Iodine and Methyl Iodide on Base and TEDA Impregnated Carbon (활성탄을 이용한 원소요오드 및 유기요오드 흡착특성)

  • Lee, Hoo-Kun;Park, Geun-Il
    • Nuclear Engineering and Technology
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    • v.28 no.1
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    • pp.44-55
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    • 1996
  • For the purpose of controlling the release of radioiodine to the environment in nuclear power plants, adsorption characteristics of elemental iodine and methyl iodide on the base carbon and 2%, 5% TEDA impregnated carbons were studied. The amounts of adsorption of elemental iodine and methyl iodide on the carbons were compared with Langmuir, Freundlich, Sips and Dubinin-Astakhov(DA) isotherm equations. Adsorption data were well correlated by the DA equation based on the potential theory. Adsorption energy distributions were obtained from the parameters of the DA equation derived from the condensation approach method. For the adsorption of methyl iodide and elemental iodine-carbon system, the DA equation can be well expressed by the degree of heterogeneity of the micropore system because the surface is nonuniform when its potential energy is unequal. The adsorption energy distribution wes investigated to find a surface heterogeneity on the carbon. The surface heterogeneity for iodine-carbon system is highly affected by the adsorbate-adsorbent interaction as well as the pore structure. The surface heterogeneity increases as a content of TEDA impregnated increases. The adsorption nature of methyl iodide on carbon turned out to be more heterogeneous than that of elemental iodine.

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Vibroacoustic response of thin power law indexed functionally graded plates

  • Baij Nath Singh;Vinayak Ranjan;R.N. Hota
    • Steel and Composite Structures
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    • v.50 no.3
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    • pp.299-318
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    • 2024
  • The main objective of this paper is to compute the far-field acoustic radiation (sound radiation) of functionally graded plates (FGM) loaded by sinusoidally varying point load subjected to the arbitrary boundary condition is carried out. The governing differential equations for thin functionally graded plates (FGM) are derived using classical plate theory (CPT) and Rayleigh integral using the elemental radiator approach. Four cases, segregated on power-law index k=0,1,5,10, are studied. A novel approach is illustrated to compute sound fields of vibrating FGM plates using the physical neutral surface with an elemental radiator approach. The material properties of the FGM plate for all cases are calculated considering the power law indexes. An in-house MATLAB code is written to compute the natural frequencies, normal surface velocities, and sound radiation fields are analytically calculated using semi-analytical formulation. Ansys is used to validate the computed sound power level. The parametric effects of the power law index, modulus ratios, different constituent of FGM plates, boundary conditions, damping loss factor on the sound power level, and radiation efficiency is illustrated. This work is the benchmark approach that clearly explains how to calculate acoustic fields using a solid layered FGM model in ANSYS ACT. It shows that it is possible to asymptotically stabilize the structure by controlling the intermittent layers' stiffness. It is found that sound fields radiated by the elemental radiators approach in MATLAB, ANSYS and literatures are in good agreement. The main novelty of this research is that the FGM plate is analyzed in the low-frequency range, where the stiffness-controlled region governs the whole analysis. It is concluded that a clamped mono-ceramic FGM plate radiates a lesser sound power level and higher radiation efficiency than a mono-metallic or metal-rich FGM plate due to higher stiffness. It is found that change in damping loss factor does not affect the same constituents of FGM plates but has significant effects on the different constituents of FGM plates.

Effects of size-dependence on static and free vibration of FGP nanobeams using finite element method based on nonlocal strain gradient theory

  • Pham, Quoc-Hoa;Nguyen, Phu-Cuong
    • Steel and Composite Structures
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    • v.45 no.3
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    • pp.331-348
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    • 2022
  • The main goal of this article is to develop the finite element formulation based on the nonlocal strain gradient and the refined higher-order deformation theory employing a new function f(z) to investigate the static bending and free vibration of functionally graded porous (FGP) nanobeams. The proposed model considers the simultaneous effects of two parameters: nonlocal and strain gradient coefficients. The nanobeam is made by FGP material that exists in un-even and logarithmic-uneven distribution. The governing equation of the nanobeam is established based on Hamilton's principle. The authors use a 2-node beam element, each node with 8 degrees of freedom (DOFs) approximated by the C1 and C2 continuous Hermit functions to obtain the elemental stiffness matrix and mass matrix. The accuracy of the proposed model is tested by comparison with the results of reputable published works. From here, the influences of the parameters: nonlocal elasticity, strain gradient, porosity, and boundary conditions are studied.

Crystal Structure, Fluorescence Property and Theoretical Calculation of the Zn(II) Complex with o-Aminobenzoic Acid and 1,10-Phenanthroline

  • Zhang, Zhongyu;Bi, Caifeng;Fan, Yuhua;Zhang, Xia;Zhang, Nan;Yan, Xingchen;Zuo, Jian
    • Bulletin of the Korean Chemical Society
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    • v.35 no.6
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    • pp.1697-1702
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    • 2014
  • A novel complex [$Zn(phen)(o-AB)_2$] [phen: 1,10-phenanthroline o-AB: o-aminobenzoic acid] was synthesized and characterized by elemental analysis and X-ray diffraction single-crystal analysis. The crystal crystallizes in monoclinic, space group P2(1)/c with $a=7.6397(6){\AA}$, $b=16.8761(18){\AA}$, $c=17.7713(19){\AA}$, ${\alpha}=90^{\circ}$, ${\beta}=98.9570(10)^{\circ}$, ${\gamma}=90^{\circ}$, $V=2.2633(4)nm^3$, Z = 4, F(000) = 1064, S = 1.058, $Dc=1.520g{\cdot}cm^{-3}$, $R_1=0.0412$, $wR_2=0.0948$, ${\mu}=1.128mm^{-1}$. The Zn(II) is six coordinated by two nitrogen and four oxygen atoms from the 1,10-phenanthroline and o-aminobenzoic acid to furnish a distorted octahedron geometry. The complex exhibits intense fluorescence at room temperature. Theoretical studies of the title complex were carried out by density functional theory (DFT) B3LYP method. CCDC: 898291.

Free vibration analysis of cracked thin plates using generalized differential quadrature element method

  • Shahverdi, Hossein;Navardi, Mohammad M.
    • Structural Engineering and Mechanics
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    • v.62 no.3
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    • pp.345-355
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    • 2017
  • The aim of the present study is to develop an elemental approach based on the differential quadrature method for free vibration analysis of cracked thin plate structures. For this purpose, the equations of motion are established using the classical plate theory. The well-known Generalized Differential Quadrature Method (GDQM) is utilized to discretize the governing equations on each computational subdomain or element. In this method, the differential terms of a quantity field at a specific computational point should be expressed in a series form of the related quantity at all other sampling points along the domain. However, the existence of any geometric discontinuity, such as a crack, in a computational domain causes some problems in the calculation of differential terms. In order to resolve this problem, the multi-block or elemental strategy is implemented to divide such geometry into several subdomains. By constructing the appropriate continuity conditions at each interface between adjacent elements and a crack tip, the whole discretized governing equations of the structure can be established. Therefore, the free vibration analysis of a cracked thin plate will be provided via the achieved eigenvalue problem. The obtained results show a good agreement in comparison with those found by finite element method.

Crystal Structure and Tautomerism Study of the Mono-protonated Metformin Salt

  • Wei, Xiaodan;Fan, Yuhua;Bi, Caifeng;Yan, Xingchen;Zhang, Xia;Li, Xin
    • Bulletin of the Korean Chemical Society
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    • v.35 no.12
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    • pp.3495-3501
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    • 2014
  • A novel crystal, the mono-protonated metformin acetate (1), was obtained and characterized by elemental analysis, IR spectroscopy and X-ray crystallography. It was found that one of the imino group in the metformin cation was protonated along with the proton transfer from the secondary amino group to the other imino group. Its crystal structure was then compared with the previously reported diprotonated metformin oxalate (2). The difference between them is that the mono-protonated metformin cations can be linked by hydrogen bonding to form dimers while the diprotonated metformin cations cannot. Both of them are stabilized by intermolecular hydrogen bonds to assemble a 3-D supermolecular structure. The four potential tautomer of the mono-protonated metformin cation (tautomers 1a, 1b, 1c and 1d) were optimized and their single point energies were calculated by Density Functional Theory (DFT) B3LYP method based on the Polarized Continuum Model (PCM) in water, which shows that the most likely existed tautomer in human cells is the same in the crystal structure. Based on the optimized structure, their Wiberg bond orders, Natural Population Analysis (NPA) atomic charges, molecular electrostatic potential (MEP) maps were calculated to analyze their electronic structures, which were then compared with the corresponding values of the diprotonated metformin cation (cation 2) and the neutral metformin (compound 3). Finally, the possible tautomeric mechanism of the mono-protonated metformin cation was discussed based on the observed phenomena.

A Study on the Problem of the Sublime in the Visual Arts - J.-F. Lyotard's Theory on the Postmodern Sublime - (시각예술에 있어서 숭고(the sublime)의 문제 : 리오타르의 포스트모던 숭고론을 중심으로)

  • Park Nam-Hee
    • Journal of Science of Art and Design
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    • v.3
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    • pp.178-224
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    • 2001
  • This thesis aims to suggest the notion of the sublime as one of the common elements of contemporary plastic arts, as a new key for the reading of our visual environment. The concept of sublimity has been one of important categories in traditional aesthetics since the eighteenth century; beyond the domain of this tradition, however, it is rigorously investigated in sociology, literary criticism, visual art theory and post-structuralist philosophy, especially the investigation of post-modern conditions by Jean-Fran cois Lyotard. Jean-Fran cois Lyotard defines sublimity as the elemental feature of the late twentieth century visual arts based on post-structuralism and suggests the feeling of the sublime as dominant sensibility in post-modern society. According to Lyotard, the sublime is a contradictory feeling of pleasure mixed with suffering as in the theory of experimental avant-gardes; the post-modern sublimity is the feeling of suffering or agony when we feel in confronting the new and the unknown. The investigation of the sublime based on Lyotard's perspectives, therefore, is meaningful in decoding contemporary visual arts. This investigation, therefore, mainly deals with the post-modern concept of the sublime and contemporary visual arts viewed in the sublime.

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