The Experts below are selected from a list of 234 Experts worldwide ranked by ideXlab platform

Sergio A. Hassan - One of the best experts on this subject based on the ideXlab platform.

  • Water-exclusion and Liquid-Structure forces in implicit solvation.
    The journal of physical chemistry. B, 2011
    Co-Authors: Sergio A. Hassan, Peter J. Steinbach
    Abstract:

    A continuum model of solvation is proposed to describe (i) long-range electrostatic effects of water exclusion resulting from incomplete and anisotropic hydration in crowded environments and (ii) short-range effects of Liquid-Structure forces on the hydrogen-bond interactions at solute/water interfaces. The model is an extension of the phenomenological screened coulomb potential-based implicit model of solvation. The developments reported here allow a more realistic representation of highly crowded and spatially heterogeneous environments, such as those in the interior of a living cell. Only the solvent is treated as a continuum medium. It is shown that the electrostatic effects of long-range water-exclusion can strongly affect protein–protein binding energies and are then related to the thermodynamics of complex formation. Hydrogen-bond interactions modulated by the Liquid Structure at interfaces are calibrated based on systematic calculations of potentials of mean force in explicit water. The electrosta...

  • Liquid-Structure Forces and Electrostatic Modulation of Biomolecular Interactions in Solution
    The journal of physical chemistry. B, 2007
    Co-Authors: Sergio A. Hassan
    Abstract:

    Molecular interactions in solution are controlled by the bulk medium and by the forces originating in the Structured region of the solvent close to the solutes. In this paper, a model of electrostatic and Liquid-Structure forces for dynamics simulations of biomolecules is presented. The model introduces information on the microscopic nature of the Liquid in the vicinity of polar and charged groups and the associated non-pairwise character of the forces, thus improving upon conventional continuum representations. The solvent is treated as a polar and polarizable medium, with dielectric properties described by an inhomogeneous version of the Onsager theory. This treatment leads to an effective position-dependent dielectric permittivity that incorporates saturation effects of the electric field and the spatial variation of the Liquid density. The non-pairwise additivity of the Liquid-Structure forces is represented by centers of force located at specific points in the Liquid phase. These out-of-the-solute ce...

Mu Shik Jhon - One of the best experts on this subject based on the ideXlab platform.

  • Equilibrium between two Liquid Structures in water: explicit representation via significant Liquid Structure theory
    Journal of Molecular Liquids, 2004
    Co-Authors: Young In Jhon, Ho Gi Kim, Mu Shik Jhon
    Abstract:

    Abstract We assumed that Liquid water was mainly composed of two hydrogen-bonded Liquid Structures between which the transformation occurred resulting in the dynamic equilibrium of them. Implanting the significant Liquid Structure theory directly to a general thermodynamic expression for the mixture of certain two species, which are in equilibrium with each other, we obtained a partition function for the above water model. Using this method, we could represent two Liquid Structures of water more explicitly in the partition function compared to the previous work. The number of water molecules (q) in a collective motion (the size of flickering cluster in Liquid water) for the transformation between two Liquid Structures has been difficult to know, and it was estimated in this work by investigating which cases showed Arrhenius type of the transformation. This value was also confirmed by considering the temperature-dependent compressibility of water and it was roughly 10–25 (more exactly 15–20). Using the induced partition function with q=20, various properties of water were calculated and they showed a good agreement with experimental data. Especially, the density maximum at 4 °C was calculated without the parameter fitting intended for it.

Masatoshi Ishikawa - One of the best experts on this subject based on the ideXlab platform.

  • Development of variable-focus lens with Liquid-membrane- Liquid Structure and 30 mm optical aperture
    MEMS Adaptive Optics VII, 2013
    Co-Authors: Lihui Wang, Hiromasa Oku, Masatoshi Ishikawa
    Abstract:

    With the purpose of designing a variable-focal lens with large optical aperture, a Liquid lens with Liquid-membrane-Liquid Structure and 30mm optical aperture is proposed. Function of the inserted membrane is stated that much stronger elastic force takes place of interface tension, and enlarging aperture size of Liquid lens becomes possible. Mechanics analysis of membrane’s deformation and finite element simulation was employed to demonstrate the elastic force maintains the deformation into a parabolic shape. Moreover, a prototype lens was designed and optical performance with a refractive power range of 7.7Diopters, and 7.13line-pair/mm resolution was measured in experiments.

  • Variable-focus lens with 30 mm optical aperture based on Liquid-membrane-Liquid Structure
    Applied Physics Letters, 2013
    Co-Authors: Lihui Wang, Hiromasa Oku, Masatoshi Ishikawa
    Abstract:

    We report a Liquid lens with a Liquid–membrane–Liquid Structure in order to realize a variable-focus lens with a large optical aperture. We studied a typical Liquid lens with a Liquid–Liquid Structure and examined its physical limitation, namely, the capillary length, restricting the design of a larger-aperture Liquid lens. We propose using elastic force instead of surface tension to acquire a much longer capillary length. We demonstrated that this approach can achieve sufficiently long capillary length when external pressure is loaded. A prototype lens with 30 mm aperture was constructed, and a resolution of 8.00 lp/mm was realized.

  • A Liquid Lens with Liquid-Membrane-Liquid Structure
    Frontiers in Optics 2012 Laser Science XXVIII, 2012
    Co-Authors: Lihui Wang, Hiromasa Oku, Masatoshi Ishikawa
    Abstract:

    A Liquid lens with Liquid-membrane-Liquid Structure is proposed. Based on elastic mechanics analysis and simulation result of elastic deformation, it demonstrates the feasibility to design large diameter Liquid lens without losing symmetric meniscus shape.

Young In Jhon - One of the best experts on this subject based on the ideXlab platform.

  • Equilibrium between two Liquid Structures in water: explicit representation via significant Liquid Structure theory
    Journal of Molecular Liquids, 2004
    Co-Authors: Young In Jhon, Ho Gi Kim, Mu Shik Jhon
    Abstract:

    Abstract We assumed that Liquid water was mainly composed of two hydrogen-bonded Liquid Structures between which the transformation occurred resulting in the dynamic equilibrium of them. Implanting the significant Liquid Structure theory directly to a general thermodynamic expression for the mixture of certain two species, which are in equilibrium with each other, we obtained a partition function for the above water model. Using this method, we could represent two Liquid Structures of water more explicitly in the partition function compared to the previous work. The number of water molecules (q) in a collective motion (the size of flickering cluster in Liquid water) for the transformation between two Liquid Structures has been difficult to know, and it was estimated in this work by investigating which cases showed Arrhenius type of the transformation. This value was also confirmed by considering the temperature-dependent compressibility of water and it was roughly 10–25 (more exactly 15–20). Using the induced partition function with q=20, various properties of water were calculated and they showed a good agreement with experimental data. Especially, the density maximum at 4 °C was calculated without the parameter fitting intended for it.

Lai Wang - One of the best experts on this subject based on the ideXlab platform.

  • The Correlation between the Liquid Structure and the Solidification MicroStructure of Sn-Cu Lead-Free Solders
    Materials Science Forum, 2010
    Co-Authors: Xuemin Pan, Ning Zhao, Rui Fang Ding, Guang Lin Wei, Lai Wang
    Abstract:

    The Liquid Structure of two lead-free solder molten alloys, Sn-0.5Cu and Sn-1.8Cu (wt.%), have been investigated using X-ray diffraction method. The main peak for Liquid Structure of Sn-0.5Cu is similar to that of pure Sn. A pre-peak has been found in the low Q part on the Structure factor S(Q) of Sn-1.8Cu tested under 320°C and the pre-peak decreases its intensity with increasing temperature, but it disappeared finally when the testing temperature reached 350°C. The microStructure of the solder matrix as well as interfacial reaction between Liquid solders and Cu substrate was also studied. The structural unit size corresponding to the pre-peak almost equals to magnitude of crystal planar distance of Cu6Sn5 phase. The appearance of a pre-peak may be due to existence of clusters with Cu6Sn5-phase-like Structure in the melt. Quantity and size of clusters increases with decreasing temperature but their structural unit size remains constant. Cu6Sn5 phases develop from incorporating and growing of the clusters during solidification, thus result in the correlation between Liquid Structure and solid microStructure.

  • The Correlation between the Liquid Structure and the Viscosity of Sn-Cu Lead-Free Solders
    Advanced Materials Research, 2010
    Co-Authors: Xuemin Pan, Ning Zhao, Rui Fang Ding, Guang Lin Wei, Lai Wang
    Abstract:

    The Liquid Structure of two lead-free solder Molten alloys, Sn-0.5Cu and Sn-1.8Cu (wt.%), has been examined using X-ray diffraction method. The main peak for Liquid Structure of Sn-0.5Cu is similar to that of pure Sn. A pre-peak has been found in the low Q part on the Structure factor S(Q) of Sn-1.8Cu tested under 320°C, but it disappeared finally when the testing temperature reached 350°C. The both viscosity was measured using a torsional oscillation viscometer. It was found that the anomalous variations of viscosity had a direct relation with the transition of the Liquid Structure, which is consonant with the results of high temperature X-ray diffraction. The microStructure of the solder matrixes as well as interfacial reaction between Liquid solders and Cu substrates was also studied. The results show that particle-like Cu6Sn5 intermetallic compounds (IMCs) emerge in Sn-1.8Cu solder matrix. The IMC layer at Sn-1.8Cu/Cu joint is thicker than that at Sn-0.5Cu/Cu interface. The correlative effect of Liquid Structure on phase evolution in the solder joints is analyzed.

  • The Liquid Structure of Sn-based lead-free solders and the correlative effect in Liquid-solid interfacial reaction
    Journal of Physics: Conference Series, 2008
    Co-Authors: Ning Zhao, Xuemin Pan, Haitao Ma, Wen Lu, Chuang Dong, Shuhong Guo, Lai Wang
    Abstract:

    Two lead-free solder alloys, Sn-0.7Cu and Sn-2Cu (wt.%), have been examined using X-ray diffraction method. The Liquid Structure of Sn-0.7Cu is similar to that of pure Sn. A pre-peak has been found in the low Q part on the Structure factor S(Q) for Sn-2Cu tested under 260°C, but it disappeared finally when the testing temperature reached 400°C. The interfacial reactions between Liquid solders and Cu substrates at 260°C were also studied. The results show that the IMC layer at Sn-2Cu/Cu joint is thicker than that at Sn-0.7Cu/Cu interface. The correlative effect of Liquid Structure on phase evolution in the solder joints are analyzed and discussed. © 2008 IOP Publishing Ltd.