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  • 1
    Electronic Resource
    Electronic Resource
    Hydriding mechanism of Mg2Ni in the presence of oxygen impurity in hydrogen (1985)
    Springer
    Journal of materials science 20 (1985), S. 2958-2964 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract For the case where oxygen is present as an impurity in hydrogen, a hydriding mechanism is proposed along with hydriding cycling of the Mg2Ni alloy. The large chemical affinity of magnesium for oxygen leads to the selective oxidation of magnesium and to the segregation of the more noble nickel component. The consequence is a progressive decrease in hydrogen storage capacity of Mg2Ni along with hydriding cycling. The segregated nickel provides active sites for chemisorption of oxygen and hydrogen. The chemisorbed oxygen accelerates the surface segregation of nickel or can form water vapour with hydrogen, or (least favourably) directly oxidizes nickel. The chemisorbed hydrogen can form water vapour with oxygen, can hydride Mg2Ni or can reduce the nickel oxide eventually formed. All these reactions are exothermic, causing an increase in temperature during the hydriding process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00553060
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  • 2
    Electronic Resource
    Electronic Resource
    A hydriding kinetic model of the Mg2Ni-H2 system (1986)
    Springer
    Journal of materials science 21 (1986), S. 346-354 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The hydriding kinetics of an Mg2Ni alloy are investigated under hydrogen pressures from 2.5 to 8 bar (0.25 to 0.8 MPa) at various temperatures (543 ⩽T ⩽ 583 K). The hydriding reaction of Mg2Ni progresses by a nucleation and growth mechanism. The rate-controlling step is analysed to be the forced flow of hydrogen molecules through pores, interparticle channels or cracks of the sample, involving heat-transfer control.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01144743
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  • 3
    Electronic Resource
    Electronic Resource
    The molecular theory of viscoelasticity for thermoplastic elastomer SBS (SIS) at large deformations (1990)
    Springer
    Rheologica acta 29 (1990), S. 31-45 
    Details
    ISSN: 1435-1528
    Keywords: Block copolymer ; microphase separation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Abstract A microstructure model for SBS and SIS triblock copolymers with hard domains as multifunctional reinforcing fillers is proposed. Based on this model and proposed mechanism of large deformations, the probability distribution function of the end-to-end vector for each constituent chain and the free energy of deformation for the total networks was calculated by the combination of statistical thermodynamics and kinetics. A new molecular theory of non-linear visco-elasticity for SBS and SIS at large deformations is presented. It is successful in relating the viscoelastic state to molecular constitution by three important parameters (C 100,C 020, andC 200) of the networks. The relations of stress to strain for four types of deformation, the elastic modulus and the constitutive equation for the stress relaxation were derived from this theory. It provides a theoretical foundation for studying the relationships of multiphase network structures and mechanical properties at large deformations. An excellent agreement between the theoretical relationships and experimental data from the experiments and the reference was obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01331799
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  • 4
    Electronic Resource
    Electronic Resource
    Elastic behaviors of swollen multiphase networks of SBS and SIS block copolymers (1993)
    Springer
    Rheologica acta 32 (1993), S. 254-262 
    Details
    ISSN: 1435-1528
    Keywords: Block copolymer ; elastic properties ; swelling ; statistical theory of viscoelasticity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Abstract A study on the swelling properties of SBS and SIS block copolymers was reported. A new relation of the elastic properties of SBS and SIS to the structure of elastomers, the swelling ratio and the nature of selective swelling agents was derived from the statistical theory of viscoelasticity developed earlier for thermoplastic elastomers SBS(SIS). The dependence of viscoelastic free energy of deformation and state equation on the nature of swelling agents and the swelling ratio was also investigated. It shows that the statistical theory of viscoelasticity for SBS(SIS) elastomers has proven to be very useful in characterizing the elastic behavior of swollen multiphase networks of SBS and SIS.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00434189
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  • 5
    Electronic Resource
    Electronic Resource
    Dielectric behavior during sol-gel transition of PEO-PPO-PEO triblock copolymer aqueous solution (2000)
    Springer
    Polymer bulletin 43 (2000), S. 497-504 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050007
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  • 6
    Electronic Resource
    Electronic Resource
    Study on the relationship between the mechanical properties and processing for self-reinforced polymers. Part 1: A theory of stress-induced crystallization for entangled polymer networks (1993)
    Springer
    Colloid & polymer science 271 (1993), S. 911-929 
    Details
    ISSN: 1435-1536
    Keywords: Stress-induced crystallization ; self-reinforced polymers ; entangled polymer networks
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A new theory of stress-induced crystallization for entangled polymer networks is presented. It is based on the theory of viscoelasticity with constraints of trapped entanglements and crystallites using a model of fibrillar and lamellar morphology engendered by the extended and folded-chain crystallization. The probability distribution function of the end-to-end vector for two kinds of constituent chains and the viscoelastic free energy of deformation for two kinds of networks have been calculated. The relationships of stress to strain for four types of deformation were derived. The theory is successful in relating the equilibrium degree of crystallinity and the melting temperature to the extension ratio for networks with stress-induced crystallization. Furthermore, the theory provides a theoretical foundation for studying the dependences of tensile modulus and strength on the processing and testing conditions for self-reinforced polymers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00654851
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  • 7
    Electronic Resource
    Electronic Resource
    H αfiltergram observations of ellerman bombs and its magnetic reconnection model (1995)
    Springer
    Astrophysics and space science 229 (1995), S. 325-339 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract From theH αfiltergram observations obtained at Ganyu station, identification and statistic works made for Ellerman bombs, it is found that they often occur in the superpenumbra area of a mature sunspot. We suggest a plasmoid model to account for the basic properties of a typical bomb: lifetime 11 min, diameter ∼ 5 × 107 cm, accompanying jet velocity ∼ 40 km/s, total energy ∼ 1027 erg,Te ∼ 104 K. First, a numerical simulation is made to prove that plasmoids can be lifted from the solar convective zone by magnetic buoyancy. Between the plasmoid and its surroundings a strong current sheet builds up in which a peculiar MHD (with plasma ponderamotive force) - resistive instability takes place. After the magnetic reconnection has begun, a local explosive instability ensues whose growth rate is so high that it allows the exhaustion of the ‘high temperature’ particles from the sheet in a short period. In this way, the temperature of a bomb may be kept unchanged or only rise slightly.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00626874
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  • 8
    Electronic Resource
    Electronic Resource
    A linear MHD instability analysis of solar mass ejections with gravitation (1987)
    Springer
    Solar physics 108 (1987), S. 347-382 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Solar mass ejections seem, on the basis of many observations, to be divided into two categories: stable and unstable. We use linear magnetohydrodynamic (MHD) instability of a cylindrical plasma in an attempt to search for a theoretical explanation for this phenomenon. The dispersion relation is obtained and solved numerically. It is found that the initial plasma-flow velocity has a significant effect on the instability criteria and growth rate. Also found is that the instability growth-rate is much larger in those cases where plasma flow exists in comparison with the static case. The wave number range where the instability may occur also becomes wider with plasma flow. Further, it is shown that the region of the instability shifts to the short wavelength region with increasing plasma-flow velocity. Therefore, the plasma column may break into small pieces, resembling the ‘melon seed’ phenomenon that has been suggested as a mechanism for mass ejection in the solar atmosphere. Under the assumption of a thin-tube approximation we show that gravity has little effect on the instability of quasi-horizontal ejection, but it has considerable effect for the vertical ejection. In order to deal with the gravitational force it is convenient to divide the problem into three cases: horizontal, vertical, and oblique. The exact analytical solution exists only in the vertical case. Asymptotic solutions are given in the horizontal and oblique cases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00214169
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  • 9
    Electronic Resource
    Electronic Resource
    Shear-induced instability and arch filament eruption: A magnetohydrodynamic (MHD) numerical simulation (1991)
    Springer
    Solar physics 134 (1991), S. 353-377 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We investigate, via a two-dimensional (nonplanar) MHD simulation, a situation wherein a bipolar magnetic field embedded in a stratified solar atmosphere (i.e., arch-filament-like structure) undergoes symmetrical shear motion at the footpoints. It was found that the vertical plasma flow velocities grow exponentially leading to a new type of global MHD-instability that could be characterized as a ‘Dynamic Shearing Instability’, with a growth rate of about √8{ovV} A a, where {ovV} A is the average Alfvén speed and a −1 is the characteristic length scale. The growth rate grows almost linearly until it reaches the same order of magnitude as the Alfvén speed. Then a nonlinear MHD instability occurs beyond this point. This simulation indicates the following physical consequences: the central loops are pinched by opposing Lorentz forces, and the outer closed loops stretch upward with the vertically-rising mass flow. This instability may apply to arch filament eruptions (AFE) and coronal mass ejections (CMEs). To illustrate the nonlinear dynamical shearing instability, a numerical example is given for three different values of the plasma beta that span several orders of magnitude. The numerical results were analyzed using a linearized asymptotic approach in which an analytical approximate solution for velocity growth is presented. Finally, this theoretical model is applied to describe the arch filament eruption as well as CMEs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00152653
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  • 10
    Electronic Resource
    Electronic Resource
    Self-similar magnetohydrodynamic solution for the dynamics of magnetic flux emergence (1996)
    Springer
    Solar physics 167 (1996), S. 57-77 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A model based on a self-similar magnetohydrodynamic (MHD) solution is presented which accounts for the dynamic behavior of the birth of an active region due to the emergence of magnetic flux. The constraints of this model are deduced from observations. Specifically, this self-similar MHD solution explains the observation that plasma flow ascends in one leg and descends in the other leg of an arch filament system (AFS). Furthermore, the solution accounts for the formation of a current sheet in which a slow reconnection may occur that may explain the appearance of bright plages in the neighborhood of an AFS.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00146328
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