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Thomas G. Mayerhöfer - One of the best experts on this subject based on the ideXlab platform.
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dispersion analysis of sodium dichromate dihydrate na2cr2o7 2h2o single crystal
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2018Co-Authors: Sonja Höfer, Jürgen Popp, Thomas G. MayerhöferAbstract:Abstract A single crystal of monoclinic sodium dichromate dihydrate was investigated by FTIR-spectroscopy in the spectral region of 4000–80 cm−1. On the measured reflection spectra dispersion analysis was performed to gain the oscillator parameters of the transition dipole moments of Na2Cr2O7·2H2O and by that the dielectric Tensor Function. The gained oscillator parameters were verified by forward-calculation of spectra using different crystal faces.
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Dispersion analysis of sodium dichromate dihydrate Na2Cr2O7·2H2O single crystal.
Spectrochimica acta. Part A Molecular and biomolecular spectroscopy, 2018Co-Authors: Sonja Höfer, Jürgen Popp, Thomas G. MayerhöferAbstract:Abstract A single crystal of monoclinic sodium dichromate dihydrate was investigated by FTIR-spectroscopy in the spectral region of 4000–80 cm−1. On the measured reflection spectra dispersion analysis was performed to gain the oscillator parameters of the transition dipole moments of Na2Cr2O7·2H2O and by that the dielectric Tensor Function. The gained oscillator parameters were verified by forward-calculation of spectra using different crystal faces.
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Complete dispersion analysis of single crystal yttrium orthosilicate
Vibrational Spectroscopy, 2016Co-Authors: Sonja Höfer, Jürgen Popp, Reinhard Uecker, Albert Kwasniewski, Thomas G. MayerhöferAbstract:Abstract A single crystal of yttrium orthosilicate was investigated by FTIR-spectroscopy in the spectral region of 150⬜2000 cm ↙1 to properly characterize this laser medium. The five reflection spectra of the crystal in principal orientation were evaluated by dispersion analysis and with the dispersion parameters the dielectric Tensor Function was obtained. Based on the dielectric Tensor Function the refractive and absorption indices as example for the optical properties were calculated.
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determination of the dielectric Tensor Function of triclinic cuso4 5h2o
Vibrational Spectroscopy, 2013Co-Authors: Sonja Höfer, Jürgen Popp, Thomas G. MayerhöferAbstract:Abstract We present the first successful dispersion analysis of a triclinic crystal in the infrared spectral region. The corresponding scheme involves the parallel evaluation of 12 polarized reflection spectra recorded from three mutual perpendicular faces of a cube-shaped crystal. The dispersion analysis was carried out on a CuSO 4 ·5H 2 O single crystal. The determined oscillator parameters and the corresponding dielectric Function Tensor were used to model the spectra of polycrystalline CuSO 4 ·5H 2 O. The good correspondence between modeled and experimental spectra of the polycrystalline species proves the correctness of the approach.
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Determination of the dielectric Tensor Function of triclinic CuSO4·5H2O
Vibrational Spectroscopy, 2013Co-Authors: Sonja Höfer, Jürgen Popp, Thomas G. MayerhöferAbstract:Abstract We present the first successful dispersion analysis of a triclinic crystal in the infrared spectral region. The corresponding scheme involves the parallel evaluation of 12 polarized reflection spectra recorded from three mutual perpendicular faces of a cube-shaped crystal. The dispersion analysis was carried out on a CuSO 4 ·5H 2 O single crystal. The determined oscillator parameters and the corresponding dielectric Function Tensor were used to model the spectra of polycrystalline CuSO 4 ·5H 2 O. The good correspondence between modeled and experimental spectra of the polycrystalline species proves the correctness of the approach.
Sonja Höfer - One of the best experts on this subject based on the ideXlab platform.
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dispersion analysis of sodium dichromate dihydrate na2cr2o7 2h2o single crystal
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2018Co-Authors: Sonja Höfer, Jürgen Popp, Thomas G. MayerhöferAbstract:Abstract A single crystal of monoclinic sodium dichromate dihydrate was investigated by FTIR-spectroscopy in the spectral region of 4000–80 cm−1. On the measured reflection spectra dispersion analysis was performed to gain the oscillator parameters of the transition dipole moments of Na2Cr2O7·2H2O and by that the dielectric Tensor Function. The gained oscillator parameters were verified by forward-calculation of spectra using different crystal faces.
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Dispersion analysis of sodium dichromate dihydrate Na2Cr2O7·2H2O single crystal.
Spectrochimica acta. Part A Molecular and biomolecular spectroscopy, 2018Co-Authors: Sonja Höfer, Jürgen Popp, Thomas G. MayerhöferAbstract:Abstract A single crystal of monoclinic sodium dichromate dihydrate was investigated by FTIR-spectroscopy in the spectral region of 4000–80 cm−1. On the measured reflection spectra dispersion analysis was performed to gain the oscillator parameters of the transition dipole moments of Na2Cr2O7·2H2O and by that the dielectric Tensor Function. The gained oscillator parameters were verified by forward-calculation of spectra using different crystal faces.
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Complete dispersion analysis of single crystal yttrium orthosilicate
Vibrational Spectroscopy, 2016Co-Authors: Sonja Höfer, Jürgen Popp, Reinhard Uecker, Albert Kwasniewski, Thomas G. MayerhöferAbstract:Abstract A single crystal of yttrium orthosilicate was investigated by FTIR-spectroscopy in the spectral region of 150⬜2000 cm ↙1 to properly characterize this laser medium. The five reflection spectra of the crystal in principal orientation were evaluated by dispersion analysis and with the dispersion parameters the dielectric Tensor Function was obtained. Based on the dielectric Tensor Function the refractive and absorption indices as example for the optical properties were calculated.
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determination of the dielectric Tensor Function of triclinic cuso4 5h2o
Vibrational Spectroscopy, 2013Co-Authors: Sonja Höfer, Jürgen Popp, Thomas G. MayerhöferAbstract:Abstract We present the first successful dispersion analysis of a triclinic crystal in the infrared spectral region. The corresponding scheme involves the parallel evaluation of 12 polarized reflection spectra recorded from three mutual perpendicular faces of a cube-shaped crystal. The dispersion analysis was carried out on a CuSO 4 ·5H 2 O single crystal. The determined oscillator parameters and the corresponding dielectric Function Tensor were used to model the spectra of polycrystalline CuSO 4 ·5H 2 O. The good correspondence between modeled and experimental spectra of the polycrystalline species proves the correctness of the approach.
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Determination of the dielectric Tensor Function of triclinic CuSO4·5H2O
Vibrational Spectroscopy, 2013Co-Authors: Sonja Höfer, Jürgen Popp, Thomas G. MayerhöferAbstract:Abstract We present the first successful dispersion analysis of a triclinic crystal in the infrared spectral region. The corresponding scheme involves the parallel evaluation of 12 polarized reflection spectra recorded from three mutual perpendicular faces of a cube-shaped crystal. The dispersion analysis was carried out on a CuSO 4 ·5H 2 O single crystal. The determined oscillator parameters and the corresponding dielectric Function Tensor were used to model the spectra of polycrystalline CuSO 4 ·5H 2 O. The good correspondence between modeled and experimental spectra of the polycrystalline species proves the correctness of the approach.
Jürgen Popp - One of the best experts on this subject based on the ideXlab platform.
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dispersion analysis of sodium dichromate dihydrate na2cr2o7 2h2o single crystal
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2018Co-Authors: Sonja Höfer, Jürgen Popp, Thomas G. MayerhöferAbstract:Abstract A single crystal of monoclinic sodium dichromate dihydrate was investigated by FTIR-spectroscopy in the spectral region of 4000–80 cm−1. On the measured reflection spectra dispersion analysis was performed to gain the oscillator parameters of the transition dipole moments of Na2Cr2O7·2H2O and by that the dielectric Tensor Function. The gained oscillator parameters were verified by forward-calculation of spectra using different crystal faces.
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Dispersion analysis of sodium dichromate dihydrate Na2Cr2O7·2H2O single crystal.
Spectrochimica acta. Part A Molecular and biomolecular spectroscopy, 2018Co-Authors: Sonja Höfer, Jürgen Popp, Thomas G. MayerhöferAbstract:Abstract A single crystal of monoclinic sodium dichromate dihydrate was investigated by FTIR-spectroscopy in the spectral region of 4000–80 cm−1. On the measured reflection spectra dispersion analysis was performed to gain the oscillator parameters of the transition dipole moments of Na2Cr2O7·2H2O and by that the dielectric Tensor Function. The gained oscillator parameters were verified by forward-calculation of spectra using different crystal faces.
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Complete dispersion analysis of single crystal yttrium orthosilicate
Vibrational Spectroscopy, 2016Co-Authors: Sonja Höfer, Jürgen Popp, Reinhard Uecker, Albert Kwasniewski, Thomas G. MayerhöferAbstract:Abstract A single crystal of yttrium orthosilicate was investigated by FTIR-spectroscopy in the spectral region of 150⬜2000 cm ↙1 to properly characterize this laser medium. The five reflection spectra of the crystal in principal orientation were evaluated by dispersion analysis and with the dispersion parameters the dielectric Tensor Function was obtained. Based on the dielectric Tensor Function the refractive and absorption indices as example for the optical properties were calculated.
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determination of the dielectric Tensor Function of triclinic cuso4 5h2o
Vibrational Spectroscopy, 2013Co-Authors: Sonja Höfer, Jürgen Popp, Thomas G. MayerhöferAbstract:Abstract We present the first successful dispersion analysis of a triclinic crystal in the infrared spectral region. The corresponding scheme involves the parallel evaluation of 12 polarized reflection spectra recorded from three mutual perpendicular faces of a cube-shaped crystal. The dispersion analysis was carried out on a CuSO 4 ·5H 2 O single crystal. The determined oscillator parameters and the corresponding dielectric Function Tensor were used to model the spectra of polycrystalline CuSO 4 ·5H 2 O. The good correspondence between modeled and experimental spectra of the polycrystalline species proves the correctness of the approach.
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Determination of the dielectric Tensor Function of triclinic CuSO4·5H2O
Vibrational Spectroscopy, 2013Co-Authors: Sonja Höfer, Jürgen Popp, Thomas G. MayerhöferAbstract:Abstract We present the first successful dispersion analysis of a triclinic crystal in the infrared spectral region. The corresponding scheme involves the parallel evaluation of 12 polarized reflection spectra recorded from three mutual perpendicular faces of a cube-shaped crystal. The dispersion analysis was carried out on a CuSO 4 ·5H 2 O single crystal. The determined oscillator parameters and the corresponding dielectric Function Tensor were used to model the spectra of polycrystalline CuSO 4 ·5H 2 O. The good correspondence between modeled and experimental spectra of the polycrystalline species proves the correctness of the approach.
Quanshui Zheng - One of the best experts on this subject based on the ideXlab platform.
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Simulation of crack tip superblunting in semi-crystalline polymers
Journal of the Mechanics and Physics of Solids, 1998Co-Authors: Ming-xiang Chen, Wei Yang, Quanshui ZhengAbstract:Abstract A model for the elastic-viscoplastic flow of semi-crystalline polymers is presented. The deformation gradient is decomposed multiplicatively into elastic and plastic parts. The reference configuration for the plastic response is chosen to coincide with the intermediate configuration on which the micromechanics texture evolution is defined. A macroscopically averaged formulation of anisotropic plastic flow is derived from the microscopic description of texture proposed by Chen et al. (1996). The derivation employs Tensor Function representation theory and the equivalence of plastic power between the macroscopic and microscopic scales. Elasticity is included to describe the effect of elastic constraint on the development of the plastic zone. Small elastic strain is assumed. A finite element scheme is formulated within the present constitutive framework. The results of detailed numerical calculations are reported, and these results are believed to elucidate the phenomenon of crack tip superblunting. The simulated results reconfirm the essential features of crack tip superblunting and its rate dependency.
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Two-Dimensional Tensor Function Representation for All Kinds of Material Symmetry
Proceedings of the Royal Society of London. Series A: Mathematical and Physical Sciences, 1993Co-Authors: Quanshui ZhengAbstract:All kinds of physically possible material symmetry in two-dimensional space were investigated in a recent work of Q.-S. Zheng and J. P. Boehler. In this paper, we establish the complete and irreducible representations with respect to every kind of material symmetry for scalar-, vector-, and second-order Tensor-valued Functions in two-dimensional space of any finite number of vectors and second-order Tensors. These representations allow general invariant forms of physical and constitutive laws of anisotropic materials to be developed in plane problems.
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Tensors which characterize anisotropies
International Journal of Engineering Science, 1993Co-Authors: Quanshui Zheng, A.j.m. SpencerAbstract:Abstract The theory of Tensor Function representations constitutes a rational basis for a consistent mathematical modelling of complex mechanical behaviour of anisotropic materials. The so-called structural Tensors , which characterize the symmetry group of anisotropy of concern, play a key role in obtaining irreducible and coordinate-free representations for anisotropic Tensor Functions. In this paper, based on available properties of Kronecker products of orthogonal transformations, a simple method of determining the structural Tensors with respect to any given symmetry group is developed. As its application, the structural Tensors corresponding to the five transverse isotropy groups, all of their finite subgroups, and the symmetry group of the 32 crystal classes, which present the most usual and worthwhile anisotropic symmetry groups, are constructed. In particular, we also show that each of these anisotropic symmetry groups can be characterized by only one simple structural Tensor.
Reza Naghdabadi - One of the best experts on this subject based on the ideXlab platform.
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Spin Tensors associated with corotational rates and corotational integrals in continua
International Journal of Solids and Structures, 2007Co-Authors: K. Ghavam, Reza NaghdabadiAbstract:Abstract In many cases of constitutive modeling of continua undergoing large deformations, use of corotational rates and integrals is inevitable to avoid the effects of rigid body rotations. Making corotational rates associated with specific spin Tensors is a matter of interest, which can help for a better physical interpretation of the deformation. In this paper, for a given kinematic Tensor Function, say G , a Tensor valued Function F as well as a spin Tensor Ω 0 is obtained in such a way that the corotational rate of F associated with the spin Tensor Ω 0 , becomes equal to G . In other words, F is the corotational integral of G associated with the spin Tensor Ω 0 . Here, G is decomposed additively into the principally diagonal and the principally off-diagonal parts. The symmetric Tensors with the same principally diagonal parts have the same Tensor valued corotational integrals, but associated with different spin Tensors, which depends on the principally off-diagonal part. For the validity of the results, the Eulerian logarithmic strain Tensor is shown to be the Tensor valued corotational integral of the strain rate Tensor, associated with the logarithmic spin. This result has separately been derived by Reinhardt & Dubey and Xiao et al. In addition, a specific corotational rate called Γ -rate and its associated spin Tensor are introduced.