• Hydrophobic attraction forces in asymmetric aqueous films[taliem.ir]

    Hydrophobic attraction forces in asymmetric aqueous films between hydrophobized mica/bare mica surfaces


    The water-structure-based, quasi-thermodynamic theory published several years ago of hydrophobic interaction forces in symmetric aqueous films [J.C. Eriksson, S. Ljunggren, P.M. Claesson, J. Chem. Soc., Faraday Trans. 2 (85) (1989) 163] has been generalized to encompass  asymmetric films between, e.g. a hydrophobized mica surface and a bare mica surface. The interaction pressures derived on this basis are in good agreement with the experimental data recorded by Claesson et al. [P.M. Claesson, P.C. Herder, C.E. Blom, B.W. Ninham, J. Colloid Interface Sci. 118 (1987) 68]. Hence, additional support is gathered for the original claim that the hydrophobic attraction is related with hydrogen-bond-dependent cluster formation processes in water contacted with a hydrophobic solid surface.

  • Nanocrystals - Nanowires - Nanolayers[taliem.ir]

    Nanocrystals – Nanowires – Nanolayers


    The dimensionality of nanosystems plays an important role in nanoscicnce and nanotechnology. In nanostructures with OD macroscopic  extension (OD – nanocrystals), 1D macroscopic extension ( I D – nanowires), or 2D macroscopic extensions (2D – nanolayers), novel  properties emerge compared to macroscopic bulk systems due to quantum conlincment, charge quantization, magnetic exchange length, etc. In the case of semiconductor systems, the nanostructures of different dimensionality are often called quantum dots, quantum wires, and quantum wells. Dimensionality effects of nanostructures have been introduced with some exemplary features in Chap. 1 and have been  shown to be of relevance in synthesis  . In the present section some generic characteristics of nanocrystals, nanowires, and nanolayers will be discussed. Dimensionality effects will be resumed later in nanoscale carbon systems  and in the discussion of nanomagnetism . Nanodots exhibit in all three spatial directions and dimensions smaller than the dc Broglic wave length of the charge carriers. Semiconductor nanodots are often embedded in another dielectric semiconductor matrix . Single quantum dots may provide innovative components for quantum information processing, quantum cryptography, or hybrid DRAM/Flash data storage. In large numbers (billions) they may form optoelectronic components, lasers or amplifiers, and new systems for communication technology, consumer electronics, or high-precision metrology.

  • Optimal geometric design of monolithic thin-film solar modules[taliem.ir]

    Optimal geometric design of monolithic thin-film solar modules: Architecture of polymer solar cells


    In this study the geometrical optimization of monolithically integrated solar cells into serially connected solar modules is reported. Based on the experimental determination of electrodes0 sheet and intermittent contact resistances, the overall series resistance of individual solar cells and interconnected solar modules is calculated. Taking a constant photocurrent generation density into account, the total Joule respectively resistive power losses are determined by a self-consistent simulation according to the 1-diode model. This method allows optimization of the solar module geometry depending on the material system applied. As an example, polymer solar modules based on ITO-electrodes and ITO-free electrodes were optimized with respect to structuring dimensions.

  • Quantum message exchanging network using[taliem.ir]

    Quantum message exchanging network using entanglement swapping and decoy photons


    We propose a scheme for secure quantum message exchanging network following the idea in entanglement swapping. In this scheme, the  servers of the network provide the service for preparing the Greenberger-Horne-Zeilinger (GHZ) entangled states as quantum channels. For preventing the eavesdropping, a security checking method is suggested. After the security check, anyone of the authorized users can  exchange his/her messages with another on the network securely and directly.