• 제목/요약/키워드: theory lattice

검색결과 162건 처리시간 0.024초

유기플라스틱 결정체의 PMR 연구 (제 1 보). 피발산 (PMR in Organic Plastic Crystals (I). Pivalic Acid)

  • 최종권;잔 그레함
    • 대한화학회지
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    • 제19권3호
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    • pp.149-155
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    • 1975
  • 플라스틱 결정체인 피발산의 temperature-dependent wide-line NMR line width, second monent 및 spin-lattice relaxation times 의 결과는 이 결정체의 특이한 운동학적 성질 및 수소결합에 기인된 것으로 해석된다. 이 분자의 운동학적 성질은 $C_3-C_3'$ reorientation 및 self-diffusion 으로 구성 되었음을 확인했다. Wide-line NMR 연구결과는 또한 Pople-Karasz 융해설과 비교검토되었고, 이 이론과의 차이점은 피발산의 수소결합에 기인되었음을 알아냈다.

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Г-DEVIATION AND LOCALIZATION

  • Albu, Toma;Teply, Mark L.
    • 대한수학회지
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    • 제38권5호
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    • pp.937-954
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    • 2001
  • This paper is a natural continuation of [2], [3], [4] and [5]. Localization techniques for modular lattices are developed. These techniques are applied to study liftings of linear order types from quotient lattices and to find Г-dense sets in certain lattices without Г-deviation in the sense of [4], where Г is a set of indecomposable linear order types.

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유기절연물의 전기전도와 절연파괴 (Electric conduction and breakdown of organic insulator)

  • 성영권
    • 전기의세계
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    • 제16권4호
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    • pp.11-16
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    • 1967
  • A physical analysis is applied to the measured phenomena of aromatic organic compounds under the uniform electric field of 0.1MV/cm through 1.5MV/cm, when they are irradiated or non-irradiated respectively. Upon the observations about irradiation effects, space charge effects and their temperature dependance, the conditions of lattice defects act conspicuously on electric conductrivity, photo conductivity and dielectric breakdown. Although the qualitative agreement with Frohlich's high energy criterion theory for the above mechanisms is poor, it is concluded that the phenomena of aromatic compounds may possibly be due to the effect of lattice defects or impurity centers generated by .gamma.-ray irradiations.

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ON FUZZY CLOSEDNESS IN LATTICE IMPLICATION ALGEBRAS

  • Jun, Young-Bae;Song, Seok-Zun;Roh, Eun-Hwan
    • Journal of applied mathematics & informatics
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    • 제11권1_2호
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    • pp.341-355
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    • 2003
  • The fuzzification of ${\bigotimes}-closed$ set is considered, and its basic properties we investigated. Characterizations of fuazzy ${\bigotimes}-closed$ set we given. Using a collection of ${\bigotimes}-closed$ sets with additional conditions, a fuzzy ${\bigotimes}-closed$ set is stated. The theory of fuzzy topological ${\bigotimes}-closed$ sets is discussed.

Topological Approach to the Rubber Elasticity of Polymer Networks

  • 손정모;박형숙
    • Bulletin of the Korean Chemical Society
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    • 제10권1호
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    • pp.84-96
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    • 1989
  • Applying the topological theory of rubber elasticity which was suggested by K. Iwata to the newly devised body-centered cubic lattice model, the authors calculated the values of four terms of the free energy to form polymer networks. Finding the projection matrix of the BCL model, and comparing this with the values of the simple cubic lattice (abbreviated to SCL hereafter) model of K. Iwata, the authors obtained the stress versus strain curves and found that the curves are in good agreement with the experimental results of poly(dimethyl siloxane) networks.

격자볼츠만법을 이용한 자유수면 거동 특성 연구 (Study on the Free Surface Behavior Using the Lattice Boltzmann Method)

  • 정노택
    • 한국해양환경ㆍ에너지학회지
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    • 제16권4호
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    • pp.255-262
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    • 2013
  • 본 연구에서는 연속체 이론을 배경으로 하며 일반적으로 많이 사용되는 Navire-Stokes방정식이 아닌 입자의 확률분포를 배경으로 하는 Boltzmann 방정식을 이용하여 자유수면을 포함하는 유동을 해석하는 전산시뮬레이션 코드를 개발하였다. 댐 붕괴시뮬레이션에 적용하여 코드의 검증을 수행하였으며, 기존의 실험 및 계산결과와 비교함과 동시에 격자볼츠만 시뮬레이션의 특성을 분석하였다. 공학적 응용을 위해서 임의 형상의 물체가 존재시에 자유수면 시뮬레이션도 수행하였다.

Thermal Behavior of Critical Micelle Concentration from the Standpoint of Flory-Huggins Model

  • Lim, Kyung-Hee
    • Bulletin of the Korean Chemical Society
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    • 제30권9호
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    • pp.2001-2006
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    • 2009
  • Temperature dependence of the critical micelle concentration (CMC), $x_{CMC}$, in micellization can be described by ln $x_{CMC}$ = A + BT + C lnT + D/T, which has been derived statistical-mechanically. Here A, B, C, and D are fitting parameters. The equation fits the CMC data better than conventionally used polynomial equations of temperature. Moreover, it yields the unique(exponent) value of 2 when the CMC is expressed in a power-law form. This finding is quite significant, because it may point to the universality of the thermal behavior of CMC. Hence, in this article, the nature of the equation ln $x_{CMC}$ = A + BT + C lnT + D/T is examined from a lattice-theory point of view through the Flory-Huggins model. It is found that a linear behavior of heat capacity change of micellization is responsible for the CMC equation of temperature.

Palladium의 Embedded Atom Method 개발 (The Embedded Atom Method Analysis of the Palldium)

  • 정영관;김경훈;김세웅;이성희;이근진;박규섭
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2002년도 춘계학술대회 논문집
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    • pp.652-655
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    • 2002
  • The embedded atom method based on the density functional theory is used for calculating ground state properties of realistic metal systems. In this paper, we had corrected constitutive formulae and parameters on the palladium for the purpose of doing Embedded Atom Method analysis. And then we have computed the properties of the palladium on the fundamental scale of the atomic structure. In result, simulated ground state properties, such as the lattice constant, elastics constants and the sublimation energy, show good agreement with Daw's simulation data and with experimental data.

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Strain-Modulated Photoluminescence in Single-Layer $MoS_2$

  • 고택영;박광희;류순민
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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    • pp.620-620
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    • 2013
  • When $MoS_2$ is thinned to single layer (1L), photoluminescence (PL) quantum yield drastically increases due to emergence of direct band gap. A recent theory predicts that the electronic structure of 1L $MoS_2$ is very sensitive to its lattice constants. We investigated the response of 1L $MoS_2$ to biaxial tensile strain using spatially resolved PL and Raman spectroscopy. Changes in the lattice constants were monitored by the Raman frequency of the in-plane ($E^1{_2g}$) mode. Systematic correlations between PL and Ramanspectral features, revealed in the preliminary results, will be further tested with samples on other substrates and against thermal stress. The results will also be discussed in regard to the theory which predicts that 1L $MoS_2$ becomes an indirect semiconductor at small tensile strain and turns metallic when further extended.

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^1H NMR Relaxation Study of Molecular Motion in the Paraelectric Phase of (NH4)2Cd2(SO4)3 Single Crystals

  • Lim, Ae-Ran;Jung, Won-Ki
    • 한국자기공명학회논문지
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    • 제14권1호
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    • pp.18-27
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    • 2010
  • The NMR spectrum and spin-lattice relaxation times, $T_1$, of the $^{1}H$ nuclei in $(NH_{4})_{2}Cd_{2}(SO_{4})_{3}$ single crystals were obtained. The two minima in $T_1$ in the paraelectric phase are attributed to the reorientational motions of the $NH_{4}^{+}$ groups. The $^{1}H\;T_1$ of the $(NH_{4})_{2}Cd_{2}(SO_{4})_{3}$ crystals can be described with Bloembergen- Purcell-Pound (BPP) theory. The experimental value of $T_1$ can be expressed in terms of an isotropic correlation time ${\tau}_H$ for molecular motions by using the BPP theory, and determine the role of protons in these processes.