• Title/Summary/Keyword: Intermolecular

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The Atomic-Scale Investigation of Friction at Hydrocarbon Interfaces via Molecular Dynamics Simulations ASIATRIB 2002

  • Harrison, J.A.;Gao, G;Chateauneuf, G.M.;Mikulski, P.T.
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2002.10b
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    • pp.59-60
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    • 2002
  • In this digest, we briefly review our current molecular dynamics (MD) simulations that utilize both the reactive empirical bond order potential (REBO) and the adaptive intermolecular REBO (AIREBO) potential energy functions. The AIREBO potential includes intermolecular interactions, so that self·assembled monolayers, and liquids, can be modeled. We have examined the mechanical and tribological properties of model self assembled monolayers and amorphous carbon films. Self-assembled monolayers are modeled by covalently bonding hydrocarbon chains to diamond substrates. Because the REBO potentials can model chemical reactions, specific compression and sliding induced chemical reactions were identified.

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The molecular structure of (+) -6-methoxy-.alpha. 1-2-naphtha-leneacetic acid determined by X-Ray method

  • Kim, Yang-Bae;Song, Hyun-June
    • Archives of Pharmacal Research
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    • v.7 no.2
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    • pp.137-139
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    • 1984
  • The molecular structure of (+)-6-Me hoxy-.alpha.-methyl-2-naphthaleneacetic acid (Naproxen), $C_{14}H_{14}O_{ 3}$, was determined by X-Ray diffraction technique. Naproxen crystallized in $P2_1$ with two molecules on the unit cell of dimensions a = 7.855, b = 5.783, c = 13.347$\AA$ and $\beta$ = $93.9^{\circ}$

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Effects of Fused Thiophene Bridges in Organic Semiconductors for Solution-Processed Small-Molecule Organic Solar Cells

  • Lee, Jae Kwan;Lee, Sol;Yun, Suk Jin
    • Bulletin of the Korean Chemical Society
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    • v.34 no.7
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    • pp.2148-2154
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    • 2013
  • Three push-pull organic semiconductors, TPA-$Th_3$-MMN (1), TPA-ThTT-MMN (2), and TPA-ThDTT-MMN (3), comprising a triphenylamine donor and a methylene malononitrile acceptor linked by various ${\pi}$-conjugated thiophene units were synthesized, and the effects of the ${\pi}$-conjugated bridging unit on the photovoltaic characteristics of solution-processed small-molecule organic solar cells based on these semiconductors were investigated. Planar bridging units with extended ${\pi}$-conjugation effectively facilitated intermolecular ${\pi}-{\pi}$ packing interactions in the solid state, resulting in enhanced $J_{sc}$ values of the SMOSCs fabricated with bulk heterojunction films.

Mechanical Properties of Hydrated Cement Paste: Development of Structure-property Relationships

  • Ghebrab, Tewodros T.;Soroushian, Parviz
    • International Journal of Concrete Structures and Materials
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    • v.4 no.1
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    • pp.37-43
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    • 2010
  • Theoretical models based on modern interpretations of the morphology and interactions of cement hydration products are developed for prediction of the mechanical properties of hydrated cement paste (hcp). The models are based on the emerging nanostructural vision of calcium silicate hydrate (C-S-H) morphology, and account for the intermolecular interactions between nano-scale calcium C-S-H particles. The models also incorporate the effects of capillary porosity and microcracking within hydrated cement paste. The intrinsic modulus of elasticity and tensile strength of hydrated cement paste are determined based on intermolecular interactions between C-S-H nano-particles. Modeling of fracture toughness indicates that frictional pull-out of the micro-scale calcium hydroxide (CH) platelets makes major contributions to the fracture energy of hcp. A tensile strength model was developed for hcp based on the linear elastic fracture mechanics theories. The predicted theoretical models are in reasonable agreements with empirical models developed based on the experimental performance of hcp.

The effect of surface charge balance on thermodynamic stability and kinetics of refolding of firefly luciferase

  • Khalifeh, Khosrow;Ranjbar, Bijan;Alipour, Bagher Said;Hosseinkhani, Saman
    • BMB Reports
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    • v.44 no.2
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    • pp.102-106
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    • 2011
  • Thermodynamic stability and refolding kinetics of firefly luciferase and three representative mutants with depletion of negative charge on a flexible loop via substitution of Glu by Arg (ER mutant) or Lys (EK mutant) as well as insertion of another Arg in ER mutants (ERR mutant) was investigated. According to thermodynamic studies, structural stability of ERR and ER mutants are enhanced compared to WT protein, whereas, these mutants become prone to aggregation at higher temperatures. Accordingly, it was concluded that enhanced structural stability of mutants depends on more compactness of folded state, whereas aggregation at higher temperatures in mutants is due to weakening of intermolecular repulsive electrostatic interactions and increase of intermolecular hydrophobic interactions. Kinetic results indicate that early events of protein folding are accelerated in mutants.

A Lattice Model for Intramolecular and Intermolecular Association in Alkane + Nonionic Surfactant Systems (알칸과 비이온계면활성 계를 위한 분자 내외부 회합을 위한 격자모델)

  • Shin, Moon-Sam
    • Proceedings of the KAIS Fall Conference
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    • 2009.12a
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    • pp.103-107
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    • 2009
  • Intramolecular association is an important contribution to the overall hydrogen bonding in supercritical fluid systems, especially in systems of colloidal and biological interest. Amphiphile systems, especially micelle and microemulsion systems, showed highly non-ideal behavior due to the intermolecular association and intramolecular association. The objective of this research is to present a lattice fluid equation of state that combines the quasi-chemical nonrandom lattice fluid model with modified Veytsman statistics for intra + inter molecular association to calculate phase behavior for mixture containing surfactant systems. The present EOS could correlate the literature data well for mixtures containing nonionic surfactant systems.

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Solution NMR spectroscopy for investigation of liquid-liquid phase separation

  • Saio, Tomohide;Okumura, Masaki;Lee, Young-Ho
    • Journal of the Korean Magnetic Resonance Society
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    • v.24 no.2
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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.