• 제목/요약/키워드: structural relaxation

검색결과 267건 처리시간 0.026초

Solution NMR spectroscopy for investigation of liquid-liquid phase separation

  • Saio, Tomohide;Okumura, Masaki;Lee, Young-Ho
    • 한국자기공명학회논문지
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    • 제24권2호
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    • pp.47-52
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    • 2020
  • Liquid-liquid phase separation (LLPS) of biomolecules, a newly-found phase behavior of molecules in the liquid phase, has shown to its relationship to various biological function and misfolding diseases. Extensive studies have increasingly revealed a general mechanism of LLPS and characterized the liquid droplet; ho wever, intermolecular interactions of proteins and structural states of LLPS-inducing proteins inside of the droplet remain largely unknown. Solution NMR spectroscopy has emerged as a powerful approach as it provides invaluable information on protein intermolecular interactions and structures at the atomic and residue level. We herein comprehensively address useful techniques of solution NMR including the effect of paramagnetic relaxation enhancement for the study on the LLPS and droplet based on recent studies.

고온인가에 따른 에폭시 복합체의 열화 및 유전특성평가 (Estimation of Degradation and Dielectric Properties for Epoxy Composites doe to Applying High Temperature)

  • 왕종배;이준웅;김재환
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1995년도 추계학술대회 논문집
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    • pp.175-178
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    • 1995
  • Distribution of relaxation time is presented in the Cole-Cole arc diagram with frequency parameter. In the case of estimation of activation energy for main chains, maximum loss frequencies of ${\alpha}$ peaks, f$\sub$m/(${\alpha}$) display curved change according to the WLF type with variations of temperature. Structural change by the filling of filler and degradation by the thermal aging can be estimated from the WLF factors, C$_1$and C$_2$in Log f$\sub$m/-1/T curves which reflect the variations of free volume and thermal expansivity of composites.

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지방산계 박막의 구조 특성 (Structural Characteristics of Fatty Acid Thin films)

  • 정유라;최용성;황종선;이경섭
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2009년도 춘계학술대회 논문집 전기설비전문위원
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    • pp.33-36
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    • 2009
  • In this paper, evaluation of physical properties was made for dielectric relaxation phenomena by the detection of the surface pressures and displacements current on the monolayer films of fatty acid monomolecular Arachidic Acid, Stearic Acid using compressing velocity. LB(Langmuir-Blodgett) thin films were manufacture by detecting deposition for the accumulation and the current was measured after the electric bias was applied across the manufactured MIM device. The physicochemical properties of the fatty acid monomolecular Arachidic Acid, Stearic Acid films surface structure has been studied by AFM. We give pressure stimulation into organic thin films and then manufacture a device under the accumulation condition that the state surface pressure is gas state, liquid state, solid state. Formation that prevent when gas phase state and liquid phase state measure but could know organic matter that molecules form equal and stable film when molecules were not distributed evenly, and accumulated in solid state only.

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Wave propagation in a generalized thermo elastic circular plate immersed in fluid

  • Selvamani, R.;Ponnusamy, P.
    • Structural Engineering and Mechanics
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    • 제46권6호
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    • pp.827-842
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    • 2013
  • In this paper, the wave propagation in generalized thermo elastic plate immersed in fluid is studied based on the Lord-Shulman (LS) and Green-Lindsay (GL) generalized two dimensional theory of thermo elasticity. Two displacement potential functions are introduced to uncouple the equations of motion. The frequency equations that include the interaction between the plate and fluid are obtained by the perfect-slip boundary conditions using the Bessel function solutions. The numerical calculations are carried out for the material Zinc and the computed non-dimensional frequency, phase velocity and attenuation coefficient are plotted as the dispersion curves for the plate with thermally insulated and isothermal boundaries. The wave characteristics are found to be more stable and realistic in the presence of thermal relaxation times and the fluid interaction.

습식 화학법으로 제조된 $PbTiO_3$의 결정화 (Crystallization of $PbTiO_3$ Prepared by Wet-Chemical Methods)

  • 최병철;이문호
    • 한국세라믹학회지
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    • 제28권11호
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    • pp.892-896
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    • 1991
  • The cyrstallization behavior of lead titanate powders prepared by sol-gel and coprecipitation techniques was investigated. The lead titanate precursors were derived from a mixed solution of lead nitrate and titanium tetrachloride at 4$0^{\circ}C$ to 43$^{\circ}C$ and pH of 9.00 to 9.75. The X-ray diffraction patterns of the dried gel and coprecipitated powders showed it to be amorphous. DTA runs of the powders indicated crystallization to occur at 475~48$0^{\circ}C$. However, the amorphous powders were partially crystallized at 400~45$0^{\circ}C$ with sufficient annealing time. The room temperature Raman spectra from heat-treated powders changed continuously from amorphous to crystalline state with increasing heat-treating temperature. By annealing coprecipitated powders, a dramatic change in the Raman spectra due to the structural relaxation as the annealing temperatures increased, was clearly visible. i.e., coprecipitated, gel, and crystalline structure, in turn.

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Annealing Effect on Structural, Electrical and Optical Properties of CdS Films Prepared by CBD Method

  • Haider, Adawiya J.;Mousa, Ali M.;Al-Jawad, Selma M.H.
    • JSTS:Journal of Semiconductor Technology and Science
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    • 제8권4호
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    • pp.326-332
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    • 2008
  • In this work CdS films were prepared by using chemical bath deposition, which is simple and inexpensive technique suitable for large deposition area. Annealing in air at different temperatures (300, 350, 400, 450 and $500^{\circ}C$) at constant time of 30 min, also for different times (15, 30, 45, 60 and 90 min) at constant temperature ($300^{\circ}C$) is achieved. X-Ray analysis has confirmed the formation of cadmium oxide (CdO) with slight increase in grain size, shift towards lower scattering angle due to relaxation in the tensile strain for deposition films, and structure change from cubic and hexagonal to the hexagonal. From electrical properties, significant increase in electrical conductivity appeared in samples annealed at $300^{\circ}C$ for 60 min, and at $350^{\circ}C$ for 30 min.

Response of temperature dependence of an elastic modulus in microstretch generalized thermoelasticity

  • Kumar, Rajneesh;Gupta, Rajani Rani
    • Structural Engineering and Mechanics
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    • 제30권5호
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    • pp.577-592
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    • 2008
  • Laplace-Fourier transform techniques are used to investigate the interaction caused by mechanical, thermal and microstress sources in a generalized thermomicrostretch elastic medium with temperature-dependent mechanical properties. The modulus of elasticity is taken as a linear function of reference temperature. The integral transforms are inverted using a numerical technique to obtain the normal stress, tangential stress, tangential couple stress, microstress and temperature distribution. Effect of temperature dependent modulus of elasticity and thermal relaxation times have been depicted graphically on the resulting quantities. Comparisons are made with the results predicted by the theories of generalized thermoelasticity. Some particular cases are also deduced from the present investigation.

Study on Residual Stress in Viscoelastic Thin Film Using Curvature Measurement Method

  • Im, Young-Tae;Park, Seung-Tae;Park, Tae-Sang;Kim, Jae-Hyun
    • Journal of Mechanical Science and Technology
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    • 제18권1호
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    • pp.12-19
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    • 2004
  • Using LSM (laser scanning method) , the radius of curvature due to thermal deformation in polyimide film coated on Si substrate is measured. Since the polyimide film shows viscoelastic behavior, i.e., the modulus and deformation of the film vary with time and temperature, we estimate the relaxation modulus and the residual stresses of the polyimide film by measuring the radius of curvature and subsequently by performing viscoelastic analysis. The residual stresses relax by an amount of 10% at 100$^{\circ}C$ and 20% at 150$^{\circ}C$ for two hours.

유도 브릴루앙-파이버 링센서에서 비안정화 현상 (Effect of Steady and Relaxation Oscillation in Brillouin-Active Fiber Ring Structural Sensors)

  • Kim, Yong-Kab;Lee, Byeong-Ha;Paek, Un-Chul
    • 한국광학회:학술대회논문집
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    • 한국광학회 2003년도 제14회 정기총회 및 03년 동계학술발표회
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    • pp.208-209
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    • 2003
  • We have developed a practical Brillouin active fiber ring sensor of length less than 20m, by employing an optical amplifier to compensate for most of the connection losses in the ring. The loss reduction brings the standard Brillouin threshold from 21 down to 0-0.1 through the enhancement of the finesse of the ring. However, in the course of our experiments, some level of temporal instability and chaotic behavior in the backscattered Stokes intensity and also in its spectral line shift were consistently observed. (omitted)

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FEM-BEM iterative coupling procedures to analyze interacting wave propagation models: fluid-fluid, solid-solid and fluid-solid analyses

  • Soares, Delfim Jr.
    • Coupled systems mechanics
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    • 제1권1호
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    • pp.19-37
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    • 2012
  • In this work, the iterative coupling of finite element and boundary element methods for the investigation of coupled fluid-fluid, solid-solid and fluid-solid wave propagation models is reviewed. In order to perform the coupling of the two numerical methods, a successive renewal of the variables on the common interface between the two sub-domains is performed through an iterative procedure until convergence is achieved. In the case of local nonlinearities within the finite element sub-domain, it is straightforward to perform the iterative coupling together with the iterations needed to solve the nonlinear system. In particular, a more efficient and stable performance of the coupling procedure is achieved by a special formulation that allows to use different time steps in each sub-domain. Optimized relaxation parameters are also considered in the analyses, in order to speed up and/or to ensure the convergence of the iterative process.