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2002


Chirality-specific nonlinear spectroscopies in isotropic media
Chirality-specific nonlinear spectroscopies in isotropic media

Fischer, P., Albrecht, A.

BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, 75(5):1119-1124, 2002, 10th International Conference on Time-Resolved Vibrational Spectroscopy (TRVS 2001), OKAZZAKI, JAPAN, MAY 21-25, 2001 (article)

Abstract
Sum or difference frequency generation (SFG or DFG) in isotropic media is in the electric-dipole approximation only symmetry allowed for optically active systems. The hyperpolarizability giving rise to these three-wave mixing processes features only one isotropic component. It factorizes into two terms, an energy (denominator) factor and a triple product of transition moments. These forbid degenerate SFG, i.e., second harmonic generation, as well as the existence of the linear electrooptic effect (Pockels effect) in isotropic media. This second order response also has no static limit, which leads to particularly strong resonance phenomena that are qualitatively different from those usually seen in the ubiquitous even-wave mixing spectroscopies. In particular, the participation of two (not the usual one) excited states is essential to achieve dramatic resonance enhancement, We report our first efforts to see such resonantly enhanced chirality specific SFG.

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DOI [BibTex]

2002


DOI [BibTex]


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Kinetics of submonolayer epitaxial growth

Amar, J. G., Family, F., Popescu, M. N.

Computer Physics Communications, 146(1):1-8, 2002 (article)

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[BibTex]

[BibTex]


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Fluids of platelike particles near a hard wall

Harnau, L., Dietrich, S.

Physical Review E, 65(2), 2002 (article)

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[BibTex]

[BibTex]


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Fundamental measure theory for hard-sphere mixtures revisited: the White Bear version

Roth, R., Evans, R., Lang, A., Kahl, G.

Journal of Physics-Condensed Matter, 14(46):12063-12078, 2002 (article)

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[BibTex]

[BibTex]


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Microscopic theory of solvent-mediated long-range forces: Influence of wetting

Archer, A. J., Evans, R., Roth, R.

Europhysics Letters, 59(4):526-532, 2002 (article)

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[BibTex]

[BibTex]


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Colloid aggregation induced by oppositely charged polyions

Harnau, L., Hansen, J. P.

Journal of Chemical Physics, 116(20):9051-9057, 2002 (article)

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[BibTex]

[BibTex]


The chiral specificity of sum-frequency generation in solutions
The chiral specificity of sum-frequency generation in solutions

Fischer, P., Beckwitt, K., Wise, F., Albrecht, A.

CHEMICAL PHYSICS LETTERS, 352(5-6):463-468, 2002 (article)

Abstract
Sum-frequency generation in isotropic media is in the electric-dipole approximation the only symmetry allowed for chiral systems. We demonstrate that the sum-frequency intensity from an optically active liquid depends quadratically on the difference in concentration of the two enantiomers. The dominant contribution to the signal is found to be due to the chirality specific electric-dipolar three-wave mixing nonlinearity. Selecting the polarization of all fields allows the chiral electric-dipolar contributions to the bulk sum-frequency signal to be discerned from any achiral magnetic-dipolar and electric-quadrupolar contributions. (C) 2002 Published by Elsevier Science B.V.

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DOI [BibTex]

DOI [BibTex]


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Self-consistent rate equation theory of cluster size distribution in aggregation phenomena

Family, F., Popescu, M. N., Amar, J. G.

Physica A, 306(1-4):129-139, 2002 (article)

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[BibTex]

[BibTex]


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Wetting and capillary nematization of binary hard-platelet and hard-rod fluids

Harnau, L., Dietrich, S.

Physical Review E, 66(5), 2002 (article)

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[BibTex]


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Simulating stochastic geometries: morphology of overlapping grains

Brodatzki, U., Mecke, K.

Computer Physics Communications, 147(1-2):218-221, 2002 (article)

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[BibTex]

[BibTex]


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Thermodynamics and phase behavior of the lamellar Zwanzig model

Harnau, L., Rowan, D., Hansen, J. P.

Journal of Chemical Physics, 117(24):11359-11365, 2002 (article)

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[BibTex]

[BibTex]


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Renormierung der Minkowski-Funktionale im morphologischen Modell

Breidenbach, B.

Universität Stuttgart, Stuttgart, 2002 (mastersthesis)

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[BibTex]

[BibTex]


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Cluster-Computing and Computational Science mit der Wuppertaler Alpha-Linux-Cluster-Engine ALiCE

Arndt, H., Arnold, G., Eicker, N., Fliegner, D., Frommer, A., Hentschke, R., Isalia, F., Kabrede, H., Krech, M., Lippert, T. H., Neff, H., Orth, B., Schilling, K., Schroers, W., Tichy, W.

Praxis der Informationsverarbeitung und Kommunikation, 25(1):21-38, 2002 (article)

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[BibTex]


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Crossover between strong- and weak-field critical adsorption and the determination of the universal exponent η⊥

Nickel, B., Schlesener, F., Donner, W., Detlefs, C., Dosch, H.

Journal of Chemical Physics, 117(2):902-908, 2002 (article)

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[BibTex]


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A novel technique for measuring diffusivities of short-lived radioisotopes in solids

Voss, T., Strohm, A., Matics, S., Scharwaechter, P., Frank, W.

Zeitschrift f\"ur Metallkunde, 93(10):1077-1082, 2002 (article)

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[BibTex]


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The shape of parallel surface: porous media, fluctuating interfaces and complex fluids

Mecke, K. R.

Physica A-Statistical Mechanics and its Applications, 314(1-4):655-662, 2002 (article)

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[BibTex]

[BibTex]


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Diffusion in amorphen Vorstufen von Si-(B-)C-N-Keramiken und verwandten Materialien

Voss, L. T.

Universität Stuttgart, Stuttgart, 2002 (phdthesis)

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[BibTex]

[BibTex]


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Strong dependence of percolation thresholds on polydispersity

Mecke, K. R., Seyfried, A.

Europhysics Letters, 58(1):28-34, 2002 (article)

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[BibTex]

[BibTex]


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Selbstdiffusion in Silizium-Germanium-Legierungen

Strohm, A.

Universität Stuttgart, Stuttgart, 2002 (phdthesis)

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link (url) [BibTex]

link (url) [BibTex]


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Self-diffusion of 31Si and 71Ge in relaxed Si0.20Ge0.80 layers

Laitinen, P., Strohm, A., Huikari, J., Nieminen, A., Voss, T., Grodon, C., Riihimäki, I., Kummer, M., Äystö, J., Dendooven, P., Räisänen, J., Frank, W.

Physical Review Letters, 89(8), 2002 (article)

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[BibTex]

[BibTex]


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Self-diffusion of 71Ge and 31Si in Si-Ge alloys

Strohm, A., Voss, T., Frank, W., Laitinen, P., Räisänen, J.

Zeitschrift f\"ur Metallkunde, 93(7):737-744, 2002 (article)

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[BibTex]

[BibTex]


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Reconstruction of complex materials by integral geometric measures

Mecke, K. R.

Journal of Materials Science \& Technology, 18(2):155-158, 2002 (article)

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[BibTex]

[BibTex]


On optical rectification in isotropic media
On optical rectification in isotropic media

Fischer, P., Albrecht, A.

LASER PHYSICS, 12(8):1177-1181, 2002 (article)

Abstract
Coherent nonlinear optical processes at second-order are only electric-dipole allowed in isotropic media that are optically active. Sum-frequency generation in chiral liquids has recently been observed, and difference-frequency and optical rectification have been predicted to exist in isotropic chiral media. Both Rayleigh-Schrodinger perturbation theory and the density matrix approach are used to discuss the quantum-chemical basis of optical rectification in optically active liquids. For pinene we compute the corresponding orientationally averaged hyperpolarizability, and estimate the light-induced dc electric polarization and the consequent voltage across a measuring capacitor it may give rise to near resonance.

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[BibTex]

[BibTex]


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Conformal map modeling of the pinning transition in Laplacian growth

Hentschel, H. G. E., Popescu, M. N., Family, F.

Physical Review E, 65(3), 2002 (article)

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[BibTex]

[BibTex]


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Geometrically-controlled twist transitions in nematic cells

Patricio, P., Telo da Gama, M. M., Dietrich, S.

Physical Review Letters, 88(24), 2002 (article)

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[BibTex]

[BibTex]


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Entropic torque

Roth, R., van Roij, R., Andrienko, D., Mecke, K. R., Dietrich, S.

Physical Review Letters, 89(8), 2002 (article)

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[BibTex]

[BibTex]


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Effective forces in colloidal mixtures: From depletion attraction to accumulation repulsion

Louis, A. A., Allahyarov, E., Löwen, H., Roth, R.

Physical Review E, 65(6), 2002 (article)

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[BibTex]

[BibTex]


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Nucleon mass and pion loops: Renormalization

Oettel, M., Thomas, A. W.

Physical Review C, 66(6), 2002 (article)

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[BibTex]

[BibTex]

2001


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Polymer depletion interaction between two parallel repulsive walls

Schlesener, F., Hanke, A., Klimpel, R., Dietrich, S.

Physical Review E, 63, 2001 (article)

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[BibTex]

2001


[BibTex]


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Positron annihilation studies on the migration of deformation induced vacancies in stainless steel AISI 316 L

Holzwarth, U., Barbieri, A., Hansen-Ilzhofer, S., Schaaff, P., Haaks, M.

Applied Physics A-Materials Science \& Processing, 73(4):467-475, 2001 (article)

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[BibTex]

[BibTex]


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Self-diffusion of 71Ge in Si-Ge

Strohm, A., Voss, T., Frank, W., Raisanen, J., Dietrich, M.

Physica B, 308, pages: 542-545, 2001 (article)

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[BibTex]

[BibTex]


Isotropic second-order nonlinear optical susceptibilities
Isotropic second-order nonlinear optical susceptibilities

Fischer, P., Buckingham, A., Albrecht, A.

PHYSICAL REVIEW A, 64(5), 2001 (article)

Abstract
The second-order nonlinear optical susceptibility, in the electric dipole approximation, is only nonvanishing for materials that are noncentrosymmetric. Should the medium be isotropic, then only a chiral system. such as an optically active liquid, satisfies this symmetry requirement. We derive the quantum-mechanical form of the isotropic component of the sum- and difference-frequency susceptibility and discuss its unusual spectral properties. We show that any coherent second-order nonlinear optical process in a system of randomly oriented molecules requires the medium to be chiral. and the incident frequencies to be different and nonzero. Furthermore, a minimum of two nondegenerate excited molecular states are needed for the isotropic part of the susceptibility to be nonvanishing. The rotationally invariant susceptibility is zero in the static field limit and shows exceptionally sensitive resonance and dephasing effects that are particular to chiral centers.

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DOI [BibTex]

DOI [BibTex]


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Crystal structures and freezing of dipolar fluids

Groh, B., Dietrich, S.

Physical Review E, 63(02), 2001 (article)

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[BibTex]

[BibTex]


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Non-Gaussian morphology on large scales: Minkowski functionals of the REFLEX cluster catalogue

Kerscher, M., Mecke, K., Schuecker, P., Böhringer, H., Guzzo, L., Collins, C. A., Schindler, S., De Grandi, S., Cruddace, R.

Astronomy & Astrophysics, 377(1):1-16, 2001 (article)

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[BibTex]

[BibTex]


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Adsorption isotherms of hydrogen: The role of thermal fluctuations

Vorberg, J., Herminghaus, S., Mecke, K.

Physical Review Letters, 87(19), 2001 (article)

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[BibTex]

[BibTex]


Reply to ``Comment on `Phenomenological damping in optical response tensors'{''}
Reply to “Comment on ‘Phenomenological damping in optical response tensors’”

Buckingham, A., Fischer, P.

PHYSICAL REVIEW A, 63(4), 2001 (article)

Abstract
We show that damping factors must not be incorporated in the perturbation of the ground state by a static electric field. If they are included, as in the theory of Stedman et al. {[}preceding Comment. Phys. Rev. A 63, 047801 (2001)], then there would be an electric dipole in the y direction induced in a hydrogen atom in the M-s = + 1/2 state by a static electric field in the x direction. Such a dipole is excluded by symmetry.

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DOI [BibTex]


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Morphological fluctuations of large-scale structure: The PSCz survey

Kerscher, M., Mecke, K., Schmalzing, J., Beisbart, C., Buchert, T., Wagner, H.

Astronomy \& Astrophysics, 373(1):1-11, 2001 (article)

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[BibTex]

[BibTex]


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Einflußvon Teilchenbestrahlung auf die Selbst- und Interdiffusion in amorphen Fe-Zr-Legierungen

Schuler, T.

Universität Stuttgart, Stuttgart, 2001 (phdthesis)

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[BibTex]

[BibTex]


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Diffusion im unterkühlten flüssigen und amorphen Zustand von Zr65Cu175,Ni10Al17,5

Schaaff, P.

Universität Stuttgart, Stuttgart, 2001 (phdthesis)

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[BibTex]

[BibTex]


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Polydisperse fluid in contact with a semipermeable membrane

Bryk, P., Patrykiejew, A., Sokolowski, S.

Molecular Physics, 99(20):1709-1717, 2001 (article)

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[BibTex]

[BibTex]


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Diffusion of 195Au in amorphous Si3N4 and Si4N3

Voss, T., Matics, S., Strohm, A., Frank, W., Bilger, G.

Physica B, 308, pages: 431-433, 2001 (article)

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[BibTex]

[BibTex]

1994


A computational and evolutionary perspective on the role of representation in computer vision
A computational and evolutionary perspective on the role of representation in computer vision

Tarr, M. J., Black, M. J.

CVGIP: Image Understanding, 60(1):65-73, July 1994 (article)

Abstract
Recently, the assumed goal of computer vision, reconstructing a representation of the scene, has been critcized as unproductive and impractical. Critics have suggested that the reconstructive approach should be supplanted by a new purposive approach that emphasizes functionality and task driven perception at the cost of general vision. In response to these arguments, we claim that the recovery paradigm central to the reconstructive approach is viable, and, moreover, provides a promising framework for understanding and modeling general purpose vision in humans and machines. An examination of the goals of vision from an evolutionary perspective and a case study involving the recovery of optic flow support this hypothesis. In particular, while we acknowledge that there are instances where the purposive approach may be appropriate, these are insufficient for implementing the wide range of visual tasks exhibited by humans (the kind of flexible vision system presumed to be an end-goal of artificial intelligence). Furthermore, there are instances, such as recent work on the estimation of optic flow, where the recovery paradigm may yield useful and robust results. Thus, contrary to certain claims, the purposive approach does not obviate the need for recovery and reconstruction of flexible representations of the world.

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pdf [BibTex]

1994


pdf [BibTex]


Reconstruction and purpose
Reconstruction and purpose

Tarr, M. J., Black, M. J.

CVGIP: Image Understanding, 60(1):113-118, July 1994 (article)

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pdf [BibTex]

pdf [BibTex]