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  • 1
    Electronic Resource
    Electronic Resource
    Cross-sectional transmission electron microscopic study of Au/GaP and Au/InP contacts (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 332-336 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Au(80 nm)/GaP(111) samples were heat treated in forming gas in the temperature range of 450–550 °C. Very thin elongated α-Au(Ga) grains were grown into the GaP at 475 °C as a result of the interface reaction between Au and GaP. A surface (interface) energy driven grain growth in Au-Ga solid solution was observed after annealing at 500 °C. At 525 °C long, flat grains were formed from the thin elongated ones of α-Au(Ga). At 550 °C the metallization melted due to its high Ga content. During the solidification the shape of drops was preserved, and the metallization consisted of Au2Ga and Au7Ga2 grains. Au(100 nm)/InP(111) samples were annealed at 375 and 400 °C in forming gas for 10 min. Elongated crystals grown into the InP substrate due to the interaction between gold and InP were observed. Au9In4 grains are situated in these pits in the matrix of the Au2P3 monoclinic phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.350277
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  • 2
    Electronic Resource
    Electronic Resource
    Phase Change during the Initial of Ni〈sub〉30〈/sub〉Fe〈sub〉70〈/sub〉(Invar) Films on MgO(001) by DC-Biased Plasma-Sputter-Deposition (1998)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 287-288 (Aug. 1998), p. 347-352 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/03/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.287-288.347.pdf
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  • 3
    Electronic Resource
    Electronic Resource
    The direct observation and investigation of the oxidation of aluminum in the transmission electron microscope (1979)
    Springer
    Oxidation of metals 13 (1979), S. 245-254 
    Details
    ISSN: 1573-4889
    Keywords: high-purity aluminum thin films ; in situ electron microscopy ; in situ evaporation ; in situ oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The authors studied the oxidation of thin aluminum films free of oxide layers in situ prepared by evaporation directly in the electron microscope under ultra-high-vacuum conditions. The oxidation was realized at various temperatures (350–500°C) and at various oxygen pressures (1–10−3 Pa). The formation and growth of the amorphous and crystalline products have been studied.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00603669
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  • 4
    Electronic Resource
    Electronic Resource
    Mathematical three-dimensional solid modeling of biventricular geometry (1993)
    Springer
    Annals of biomedical engineering 21 (1993), S. 199-219 
    Details
    ISSN: 1573-9686
    Keywords: Cardiac representation ; Ventricular geometry ; Finite element analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract The characterization of regional myocardial stress distribution has been limited by the use of idealized mathematical representations of biventricular geometry. State-of-the-art computer-aided design and engineering (CAD/CAE) techniques can be used to create complete, unambiguous mathematical representations (solid models) of complex object geometry that are suitable for a variety of applications, including stress-strain analyses. We have used advanced CAD/CAE software to create a 3-D solid model of the biventricular unit using planar geometric data extracted from anex vivo canine heart. Volumetric analysis revealed global volume errors of 4.7%, −1.3%, −1.6%, and −1.1% for the left ventricular cavity, right ventricular cavity, myocardial wall, and total enclosed volumes, respectively. Model errors for 34 in-plane area and circumference determinations (mean ±SD) were 5.3±6.7% and 3.8±2.7%. Error analysis suggested that model volume errors may be due to operator variability. These results demonstrate that solid modeling of theex vivo biventricular unit yields an accurate mathematical representation of myocardial geometry which is suitable for meshing and subsequent finite element analysis. The use of CAD/CAE solid modeling in the representation of biventricular geometry may thereby facilitate the characterization of regional myocardial stress distribution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02368177
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Myocardial material property determination in the in vivo heart using magnetic resonance imaging (1996)
    Springer
    The international journal of cardiovascular imaging 12 (1996), S. 153-167 
    Details
    ISSN: 1573-0743
    Keywords: finite element analysis (FEA) ; material properties ; magnetic resonance imaging (MRI)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Objectives: To determine nonlinear material properties of passive, diastolic myocardium using magnetic resonance imaging (MRI) tissue-tagging, finite element analysis (FEA) and nonlinear optimization.Background: Alterations in the diastolic material properties of myocardium may pre-date the onset of or exist exclusive of systolic ventricular dysfunction in disease states such as hypertrophy and heart failure. Accordingly, significant effort has been expended recently to characterize the material properties of myocardium in diastole. The present study defines a new technique for determining material properties of passive myocardium using finite element (FE) models of the heart, MRI tissue-tagging and nonlinear optimization. This material parameter estimation algorithm is employed to estimate nonlinear material parameters in thein vivo canine heart and provides the necessary framework to study the full complexities of myocardial material behavior in health and disease.Methods and results: Material parameters for a proposed exponential strain energy function were determined by minimizing the least squares difference between FE model-predicted and MRI-measured diastolic strains. Six mongrel dogs underwent MRI imaging with radiofrequency (RF) tissue-tagging. Two-dimensional diastolic strains were measured from the deformations of the MRI tag lines. Finite element models were constructed from early diastolic images and were loaded with the mean early to late left ventricular and right ventricular diastolic change in pressure measured at the time of imaging. A nonlinear optimization algorithm was employed to solve the least squares objective function for the material parameters. Average material parameters for the six dogs wereE=28,722 ± 15,984 dynes/cm2 andc=0.00182 ± 0.00232 cm2/dyne.Conclusion: This parameter estimation algorithm provides the necessary framework for estimating the nonlinear, anisotropic and non-homogeneous material properties of passive myocardium in health and disease in thein vivo beating heart.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01806218
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  • 6
    Electronic Resource
    Electronic Resource
    Linear equality constraints in finite element approximationThis paper was presented at the Seventh U.S. National Congress of Applied Mechanics, University of Colorado, 3-7 June, 1974. (1975)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 9 (1975), S. 563-580 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The typical numerical problem associated with finite element approximations is a quadratic programming problem with linear equality constraints. When nodal variables are employed, the coefficient matrix of the constraint equations, [A], acquires a block-diagonal structure. The transformation from polynomial coefficients to nodal variables involves finding a basis for [A] and computing its inverse.Simultaneous satisfaction of completeness and C1 (or higher) continuity requirements establishes linear relationships among the nodal variables and precludes inversion of the basis by exclusively element-level operations.Linear dependencies among the constraint equations and among the nodal variables can be evaluated by the simplex method. The computational procedure is outlined.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620090306
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  • 7
    Electronic Resource
    Electronic Resource
    Generalized stress intensity factors in linear elastostatics (1995)
    Springer
    International journal of fracture 72 (1995), S. 223-240 
    Details
    ISSN: 1573-2673
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The solution of two-dimensional linear elastostatic problems in the neighborhood of singular points is discussed. A reliable and efficient method for computing the eigenpairs that characterize the exact solution and their coefficients, called the generalized stress intensity factors, by the finite element method is demonstrated. Examples, representing three very different kinds of singular points demonstrate that the method works well and produces results of high accuracy. Importantly, the method is applicable to anisotropic materials, multi-material interfaces, and cases where the singularities are characterized by complex eigenpairs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00037312
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  • 8
    Electronic Resource
    Electronic Resource
    Convergence of stress maxima in finite element computations (1994)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 10 (1994), S. 683-697 
    Details
    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The convergence of stress maxima, computed directly from finite element solutions, is investigated with respect to a family of exact solutions characterized by varying degrees of smoothness. The performances of h- and p-extensions and the product and trunk spaces are evaluated and documented with respect to a family of benchmark problems. In uniform p-extensions a characteristic pattern in the convergence of stress maxima was observed. There does not appear to be a clear-cut advantage of the product space over the trunk space in this respect. The much faster convergence of stress maxima in the case of p-extensions, as compared with h-extensions, is evident from the results.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cnm.1640100903
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  • 9
    Electronic Resource
    Electronic Resource
    Study of Low-energy Atomic Mixing by Means of Auger Depth Profiling, XTEM and TRIM Simulation on Ge/Si Multilayer System (1996)
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 24 (1996), S. 476-480 
    Details
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Low-energy atomic mixing is experimentally studied on a Ge/Si amorphous multilayer system by means of Auger depth profiling and XTEM. The ion etching was performed by using Ar ions of energy 500 eV (XTEM) and 618 eV (Auger) and angle of incidence 〉84° and the specimen was rotated during sputtering. Applying these conditions it is believed that the interface broadening occurs mainly because of atomic mixing because the surface roughening is negligible. The Auger depth profile was carried out on a specimen containing Ge/Si strips parallel to the surface. The extent of the atomic mixing was determined by comparing the depth profile to profiles provided by dynamic TRIM simulation. For ion milling another geometry was used; the Ge/Si strips were perpendicular to the surface. A very thin (2 nm) TEM specimen was prepared and the thickness of the completely mixed region could be directly estimated from the TEM image: 1 nm at 500 eV ion energy and 85° angle of incidence. The TEM image also shows that the atomic mixed region is asymmetric.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 10
    Electronic Resource
    Electronic Resource
    Improved depth resolution of AES in-depth profiling (1992)
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 19 (1992), S. 77-79 
    Details
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: In the case of conventional Auger in-depth profiling, the depth resolution increases with the thickness of the removed layer. It was demonstrated that by rotating the specimen, the depth resolution improves drastically in certain cases. Independently from this, A. Barna developed a phenomenological model to describe the change of surface topography developing due to ion sputtering. Based on his results, an Auger in-depth profiling device has been built. The capability of the device was checked by measuring in-depth profiles of Ni—Cr multilayer structure. The depth resolution determined from the measured profile is roughly constant along the depth.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/sia.740190117
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