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91.
Falmbigl M Chen MX Grytsiv A Rogl P Royanian E Michor H Bauer E Podloucky R Giester G 《Dalton transactions (Cambridge, England : 2003)》2012,41(29):8839-8849
The phase relations, crystal structure and thermoelectric properties of the type-I solid solution Ba(8)Ni(x)Si(46-x) were investigated. Based on X-ray diffraction, differential thermal analysis and electron probe microanalysis data, a partial phase diagram was constructed for the Si-rich part of ternary system Ba-Ni-Si at 800 °C. The solubility range of Ni in the clathrate-I phase at 800 °C was determined (2.9 ≤x≤ 3.8) and thermoelectric properties, namely electrical resistivity, Seebeck-coefficient and thermal conductivity, were measured in the temperature range from 300 to 850 K. A shift of the thermoelectric properties from a predominantly metallic to a more semiconducting behavior was observed for an increasing Ni-content. Density functional calculations revealed a significant decrease of the gap width in the density of states induced by the incorporation of Ni. Electrical resistivity and Seebeck coefficients for Ba(8)Ni(x)Si(46-x) with 3.3 ≤x≤ 3.8 have been modeled within the rigid band approximation. 相似文献
92.
Franchini C Li F Surnev S Podloucky R Allegretti F Netzer FP 《J Phys Condens Matter》2012,24(4):042001
The growth of ultrathin two-dimensional manganese oxide nanostripes on vicinal Pd(1 1 N) surfaces leads to particular stable configurations for certain combinations of oxide stripe and substrate terrace widths. Scanning tunneling microscopy and high-resolution low-energy electron diffraction measurements reveal highly ordered nanostructured surfaces with excellent local and long-range order. Density functional theory calculations provide the physical origin of the stabilization mechanism of 'magic width' stripes in terms of a finite-size effect, caused by the significant relaxations observed at the stripe boundaries. 相似文献
93.
This work deals with the modeling and simulation of non-Newtonian jet dynamics. Proceeding from a 3d boundary value problem of upper-convected Maxwell equations, a 1d viscoelastic string model can be derived asymptotically. The resulting system of PDEs has a hyperbolic-elliptic character with an additional differential constraint. Its applicability regime is limited depending on physical parameters and boundary conditions. Numerical results are shown for gravitational in-/outflow set-ups. (© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
94.
Raimund Bürger Sarvesh Kumar Sudarshan Kumar Kenettinkara Ricardo Ruiz-Baier 《PAMM》2016,16(1):763-764
An oil-water flow-transport problem in a heterogeneous porous medium (HPM), given by the Brinkman model coupled with a fractional flow formulation, is solved numerically by a discontinuous finite volume element (DFVE) method coupled with a Runge-Kutta Discontinuous Galerkin (RKDG) scheme. A new (original) numerical example is presented. (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
95.
96.
It is shown that a large class of two‐dimensional NMR spectra is characterized by a matrix algebra and an invariant subspace.
Both the matrix algebra and the invariant subspace are determined by the system matrices of the bilinear system which describes
the NMR experiments.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
97.
Zbigniew Galazka Steffen Ganschow Klaus Irmscher Detlef Klimm Martin Albrecht Robert Schewski Mike Pietsch Tobias Schulz Andrea Dittmar Albert Kwasniewski Raimund Grueneberg Saud Bin Anooz Andreas Popp Uta Juda Isabelle M. Hanke Thomas Schroeder Matthias Bickermann 《Progress in Crystal Growth and Characterization of Materials》2021,67(1):100511
In the course of development of transparent semiconducting oxides (TSOs) we compare the growth and basic physical properties bulk single crystals of ultra-wide bandgap (UWBG) TSOs, namely β-Ga2O3 and Ga-based spinels MgGa2O4, ZnGa2O4, and Zn1-xMgxGa2O4. High melting points of the materials of about 1800 -1930 °C and their thermal instability, including incongruent decomposition of Ga-based spinels, require additional tools to obtain large crystal volume of high structural quality that can be used for electronic and optoelectronic devices. Bulk β-Ga2O3 single crystals were grown by the Czochralski method with a diameter up to 2 inch, while the Ga-based spinel single crystals either by the Czochralski, Kyropoulos-like, or vertical gradient freeze / Bridgman methods with a volume of several to over a dozen cm3. The UWBG TSOs discussed here have optical bandgaps of about 4.6 - 5 eV and great transparency in the UV / visible spectrum. The materials can be obtained as electrical insulators, n-type semiconductors, or n-type degenerate semiconductors. The free electron concentration (ne) of bulk β-Ga2O3 crystals can be tuned within three orders of magnitude 1016 - 1019 cm?3 with a maximum Hall electron mobility (μ) of 160 cm2V?1s?1, that gradually decreases with ne. In the case of the bulk Ga-based spinel crystals with no intentional doping, the maximum of ne and μ increase with decreasing the Mg content in the compound and reach values of about 1020 cm?3 and about 100 cm2V?1s?1 (at ne > 1019 cm?3), respectively, for pure ZnGa2O4. 相似文献
98.
A Diffusively Corrected Multiclass Lighthill-Whitham-Richards Traffic Model with Anticipation Lengths and Reaction Times 下载免费PDF全文
Raimund Bü rger Pep Mulet & Luis M. Villada 《advances in applied mathematics and mechanics.》2013,5(5):728-758
Multiclass Lighthill-Whitham-Richards traffic models [Benzoni-Gavage and
Colombo, Euro. J. Appl. Math., 14 (2003), pp. 587–612; Wong and Wong, Transp. Res.
A, 36 (2002), pp. 827–841] give rise to first-order systems of conservation laws that are
hyperbolic under usual conditions, so that their associated Cauchy problems are well-posed. Anticipation lengths and reaction times can be incorporated into these models
by adding certain conservative second-order terms to these first-order conservation
laws. These terms can be diffusive under certain circumstances, thus, in principle, ensuring the stability of the solutions. The purpose of this paper is to analyze the stability of these diffusively corrected models under varying reaction times and anticipation
lengths. It is demonstrated that instabilities may develop for high reaction times and
short anticipation lengths, and that these instabilities may have controlled frequencies
and amplitudes due to their nonlinear nature. 相似文献
99.
100.
Raimund Seidel 《Combinatorica》1998,18(2):297-299
n points in the plane is at most .
Received: November 1, 1995 相似文献