The Experts below are selected from a list of 48 Experts worldwide ranked by ideXlab platform

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

  • A current account of chain extension, Fibrous Crystallization, and fiber formation
    Journal of Polymer Science: Polymer Symposia, 2007
    Co-Authors: A Keller
    Abstract:

    A broad, rather personal survey is presented on chain alignment and Fibrous Crystallization. First, attention is drawn to the fact that Fibrous Crystal entities can be of fundamentally different origin and certain methods for their identification are proposed. Following this, the largest part of the survey is concerned with Fibrous Crystallization from pre-extended molecules. As a first step, methods for extending chains and for observing their extension are outlined. Elongational flow is receiving special attention: conditions by which it can lead to ultrahigh chain extension are briefly defined as high-lighted both by a priori considerations and by most recent experiments, methods of realizing these conditions being indicated both in solutions and melts. Following this, attention is given to the mode of Crystallization of extended chains and to the structures which arise. Amongst the many factors involved, the part played by the local flow field arising from the presence of the growing Crystal entity within the general flow field is outlined, leading up to the basic mechanism by which Fibrous Crystals grow. It is shown how the recognition of these principles can be utilized for producing Crystalline fibers. The unusual thermal and mechanical properties of the products with special emphasis on melting behavior and modulus are indicated. A short section is devoted to the achievement of very high chain extensions by means of deforming material Crystalline to begin with and the resulting products are contrasted with those obtained by means of Crystallizing pre-extended chains as regards thermal and mechanical behavior.

H. Aizawa - One of the best experts on this subject based on the ideXlab platform.

  • Growth of lithium borate Crystals from the vitreous state
    Journal of Materials Research, 1994
    Co-Authors: T. Katsumata, T. Yoshimura, K. Kanazawa, H. Aizawa
    Abstract:

    The morphology and the growth mechanism of lithium borate Crystals from the vitreous state have been studied for various compositions, X = B/(Li + B), from 0.62 to 0.75. Crystalline phases and morphology of grown Crystals varied with the composition. Octahedral and/or spherical Li2B4O7 Crystals are seen in the specimen with X = 0.62, 0.64, 0.67, and 0.68. The spherical Crystal is composed of an octahedral core and Fibrous Crystals. The size of the core varied with the composition of the starting glass, X. The Fibrous Crystal growth is supposed to arise from the morphological instability due to the compositional variation caused by the solute pileup at the growth interface.

Seung Bin Park - One of the best experts on this subject based on the ideXlab platform.

  • Effect of precursors on the morphology of lithium aluminate prepared by hydrothermal treatment
    Journal of Materials Science, 2000
    Co-Authors: Sang Woon Kwon, Seung Bin Park
    Abstract:

    Hydrothermal treatment method was proposed to prepare pure LiAlO_2 with Fibrous Crystal morphology and the effect of precursors on the morphology of lithium aluminate was investigated. Lithium butoxide-aluminum butoxide system gave mostly rod-like β-LiAlO_2 Crystal. As the length of alkoxy group decreases, the fraction of plate shape Crystals was increased and boehmite was dominant Crystal phase. Needle-shape β-LiAlO_2 was produced from lithium nitrate-aluminum butoxide-sodium hydroxide system with the mole ratio of 6:1:3, respectively. β-LiAlO_2 prepared by hydrothermal treatment was transformed to γ-LiAlO_2 at 750–850°C. The specific surface area of γ-LiAlO_2 powders was above 10 m^2/g.

G.c. Stevens - One of the best experts on this subject based on the ideXlab platform.

  • Two conductive phases of 1,3-dimethylimidazolium-(TCNQ)2 complex salt
    Synthetic Metals, 1996
    Co-Authors: S. Nešprek, Ladislav Kalvoda, L. Machová, Jiří Pfleger, G.c. Stevens
    Abstract:

    Abstract Two conductive phases were found by Crystallization of the complex ion-radical salt of the 1,3-dimethylimidazolium 7,7′,8,8′-tetracyano1,4-quinodimethane (TCNQ) under different conditions: (i) bulk Crystallization from the acetonitrile solution and (ii) Crystallization on a glass substrate giving rise to an interconnected Fibrous Crystal conductive network (σ = 1.7 mS −1 ). The electrical conductivity of the latter phase is more than four orders of magnitude higher than that of the former phase. The Crystal lattices of both phases are different. The first phase is triclinia ( P 1) with cell parameters a = 7.811 A, b = 13.378 A, c = 7.276 A, α = 93.152 °, β = 113.739 °, γ = 106.068 °. Indexing of the X-ray diffraction patterns recorded with samples of the latter phase gives a = 13.65 A, b = 12.70 A, c = 3.80 A, γ = 108.3 °; α and β could not be determined.

Hiroyuki Mochizuki - One of the best experts on this subject based on the ideXlab platform.