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2020


Transient coarsening and the motility of optically heated Janus colloids in a binary liquid mixture
Transient coarsening and the motility of optically heated Janus colloids in a binary liquid mixture

Gomez-Solano, J., Roy, S., Araki, T., Dietrich, S., Maciolek, A.

Soft Matter, 16, pages: 8359-8371, Royal Society of Chemistry, August 2020 (article)

Abstract
A gold-capped Janus particle suspended in a near-critical binary liquid mixture can self-propel under illumination. We have immobilized such a particle in a narrow channel and carried out a combined experimental and theoretical study of the non-equilibrium dynamics of a binary solvent around it – lasting from the very moment of switching illumination on until the steady state is reached. In the theoretical study we use both a purely diffusive and a hydrodynamic model, which we solve numerically. Our results demonstrate a remarkable complexity of the time evolution of the concentration field around the colloid. This evolution is governed by the combined effects of the temperature gradient and the wettability, and crucially depends on whether the colloid is free to move or is trapped. For the trapped colloid, all approaches indicate that the early time dynamics is purely diffusive and characterized by composition layers travelling with constant speed from the surface of the colloid into the bulk of the solvent. Subsequently, hydrodynamic effects set in. Anomalously large nonequilibrium fluctuations, which result from the temperature gradient and the vicinity of the critical point of the binary liquid mixture, give rise to strong concentration fluctuations in the solvent and to permanently changing coarsening patterns not observed for a mobile particle. The early time dynamics around initially still Janus colloids produces a force which is able to set the Janus colloid into motion. The propulsion due to this transient dynamics is in the direction opposite to that observed after the steady state is attained.

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link (url) DOI [BibTex]

2020


link (url) DOI [BibTex]


Interface-mediated spontaneous symmetry breaking and mutual communication between drops containing chemically active particles
Interface-mediated spontaneous symmetry breaking and mutual communication between drops containing chemically active particles

Singh, D., Domínguez, A., Choudhury, U., Kottapalli, S., Popescu, M., Dietrich, S., Fischer, P.

Nature Communications, 11(2210), May 2020 (article)

Abstract
Symmetry breaking and the emergence of self-organized patterns is the hallmark of com- plexity. Here, we demonstrate that a sessile drop, containing titania powder particles with negligible self-propulsion, exhibits a transition to collective motion leading to self-organized flow patterns. This phenomenology emerges through a novel mechanism involving the interplay between the chemical activity of the photocatalytic particles, which induces Mar- angoni stresses at the liquid–liquid interface, and the geometrical confinement provided by the drop. The response of the interface to the chemical activity of the particles is the source of a significantly amplified hydrodynamic flow within the drop, which moves the particles. Furthermore, in ensembles of such active drops long-ranged ordering of the flow patterns within the drops is observed. We show that the ordering is dictated by a chemical com- munication between drops, i.e., an alignment of the flow patterns is induced by the gradients of the chemicals emanating from the active particles, rather than by hydrodynamic interactions.

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link (url) DOI [BibTex]


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Axisymmetric spheroidal squirmers and self-diffusiophoretic particles

Pöhnl, R., Popescu, M. N., Uspal, W. E.

Journal of Physics: Condensed Matter, 32(16), IOP Publishing, Bristol, 2020 (article)

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DOI [BibTex]

DOI [BibTex]


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Tracer diffusion on a crowded random Manhattan lattice

Mej\’\ia-Monasterio, C., Nechaev, S., Oshanin, G., Vasilyev, O.

New Journal of Physics, 22(3), IOP Publishing, Bristol, 2020 (article)

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DOI [BibTex]

DOI [BibTex]


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Wetting transitions on soft substrates

Napiorkowski, M., Schimmele, L., Dietrich, S.

{EPL}, 129(1), EDP Science, Les-Ulis, 2020 (article)

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DOI [BibTex]

DOI [BibTex]


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Blessing and Curse: How a Supercapacitor Large Capacitance Causes its Slow Charging

Lian, C., Janssen, M., Liu, H., van Roij, R.

Physical Review Letters, 124(7), American Physical Society, Woodbury, N.Y., 2020 (article)

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DOI [BibTex]

DOI [BibTex]


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Interplay of quenching temperature and drift in Brownian dynamics

Khalilian, H., Nejad, M. R., Moghaddam, A. G., Rohwer, C. M.

EPL, 128(6), EDP Science, Les-Ulis, 2020 (article)

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DOI [BibTex]

DOI [BibTex]


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Fractal-seaweeds type functionalization of graphene

Amsharov, K., Sharapa, D. I., Vasilyev, O. A., Martin, O., Hauke, F., Görling, A., Soni, H., Hirsch, A.

Carbon, 158, pages: 435-448, Elsevier, Amsterdam, 2020 (article)

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DOI [BibTex]

DOI [BibTex]


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Effective pair interaction of patchy particles in critical fluids

Farahmand Bafi, N., Nowakowski, P., Dietrich, S.

The Journal of Chemical Physics, 152(11), American Institute of Physics, Woodbury, N.Y., 2020 (article)

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DOI [BibTex]

DOI [BibTex]


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Cassie-Wenzel transition of a binary liquid mixture on a nanosculptured surface

Singh, S. L., Schimmele, L., Dietrich, S.

Physical Review E, 101(5), American Physical Society, Melville, NY, 2020 (article)

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DOI [BibTex]

DOI [BibTex]


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Energy storage in steady states under cyclic local energy input

Zhang, Y., Holyst, R., Maciolek, A.

Physical Review E, 101(1), American Physical Society, Melville, NY, 2020 (article)

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DOI [BibTex]

DOI [BibTex]


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Numerical simulations of self-diffusiophoretic colloids at fluid interfaces

Peter, T., Malgaretti, P., Rivas, N., Scagliarini, A., Harting, J., Dietrich, S.

Soft Matter, 16(14):3536-3547, Royal Society of Chemistry, Cambridge, UK, 2020 (article)

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DOI [BibTex]

DOI [BibTex]

2013


Quasi-Newton Methods: A New Direction
Quasi-Newton Methods: A New Direction

Hennig, P., Kiefel, M.

Journal of Machine Learning Research, 14(1):843-865, March 2013 (article)

Abstract
Four decades after their invention, quasi-Newton methods are still state of the art in unconstrained numerical optimization. Although not usually interpreted thus, these are learning algorithms that fit a local quadratic approximation to the objective function. We show that many, including the most popular, quasi-Newton methods can be interpreted as approximations of Bayesian linear regression under varying prior assumptions. This new notion elucidates some shortcomings of classical algorithms, and lights the way to a novel nonparametric quasi-Newton method, which is able to make more efficient use of available information at computational cost similar to its predecessors.

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website+code pdf link (url) [BibTex]

2013


website+code pdf link (url) [BibTex]


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The Randomized Dependence Coefficient

Lopez-Paz, D., Hennig, P., Schölkopf, B.

Neural Information Processing Systems (NIPS), 2013 (poster)

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PDF [BibTex]

PDF [BibTex]


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Analytical probabilistic modeling for radiation therapy treatment planning

Bangert, M., Hennig, P., Oelfke, U.

Physics in Medicine and Biology, 58(16):5401-5419, 2013 (article)

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PDF DOI [BibTex]

PDF DOI [BibTex]


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Self-Propelled Micromotors for Cleaning Polluted Watter

Soler, L., Magdanz, V., Fomin, V. M., Sanchez, S., Schmidt, O. G.

ACS Nano, 11, pages: 9611-9620, American Chemical Society, Washington, DC, 2013 (article)

Abstract
We describe the use of catalytically self-propelled microjets (dubbed micromotors) for degrading organic pollutants in water via the Fenton oxidation process. The tubular micromotors are composed of rolled-up functional nanomembranes consisting of Fe/Pt bilayers. The micromotors contain double functionality within their architecture, i.e., the inner Pt for the self-propulsion and the outer Fe for the in situ generation of ferrous ions boosting the remediation of contaminated water.The degradation of organic pollutants takes place in the presence of hydrogen peroxide, which acts as a reagent for the Fenton reaction and as main fuel to propel the micromotors. Factors influencing the efficiency of the Fenton oxidation process, including thickness of the Fe layer, pH, and concentration of hydrogen peroxide, are investigated. The ability of these catalytically self-propelled micromotors to improve intermixing in liquids results in the removal of organic pollutants ca. 12 times faster than when the Fenton oxidation process is carried out without catalytically active micromotors. The enhanced reaction\textendashdiffusion provided by micromotors has been theoretically modeled. The synergy between the internal and external functionalities of the micromotors, without the need of further functionalization, results into an enhanced degradation of nonbiodegradable and dangerous organic pollutants at small-scale environments and holds considerable promise for the remediation of contaminated water.

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DOI [BibTex]

DOI [BibTex]


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Stability of thin liquid films and sessile droplets under confinement

Dörfler, F., Rauscher, M., Dietrich, S.

Physical Review E, 88(1), American Physical Society, Melville, NY, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Nonequilibrium interfaces in colloidal fluids

Bier, M., Arnold, D.

Physical Review E, 88(6), American Physical Society, Melville, NY, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Colloidal particles at fluid interfaces: Effective interactions, dynamics and a gravitation\textendashlike instability

Bleibel, J., Dom\’\inguez, A., Oettel, M.

The European Physical Journal Special Topics, 222(11):3071-3087, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Anomalous transport in the crowded world of biological cells

Höfling, Felix, Franosch, Thomas

Reports on Progress in Physics, 76(4), IOP Pub., London, 2013, author: Höfling, Felix (article)

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link (url) DOI [BibTex]

link (url) DOI [BibTex]


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Flow pattern in the vicinity of self-propelling hot Janus particles

Bickel, T., Majee, A., Würger, A.

Physical Review E, 88(1), American Physical Society, Melville, NY, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Nonequilibrium Critical Casimir Effect in Binary Fluids

Furukawa, A., Gambassi, A., Dietrich, S., Tanaka, H.

Physical Review Letters, 111(5), American Physical Society, Woodbury, N.Y., 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Many-body effects for critical Casimir forces

Gomes de Mattos, T., Harnau, L., Dietrich, S.

The Journal of Chemical Physics, 138(7), 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Propulsion Mechanism of Catalytic Microjet Engines

Magdanz, V., Fomin, V. M., Soler, L., Sanchez, S., Schmidt, O. G., Hippler, M.

IEEE Transactions on Robotics and Automation, pages: 40-48, IEEE, New York, NY, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Impedance spectroscopy of ions at liquid-liquid interfaces

Bier, M., Reindl, A.

Physical Review E, 88(5), American Physical Society, Melville, NY, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Precursors of order in aggregates of patchy particles

Vasilyev, O., Klumov, B. A., Tkachenko, A. V.

Physical Review E, 88(1), American Physical Society, Melville, NY, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Two-temperature Langevin dynamics in a parabolic potential

Dotsenko, V., Maciolek, Anna, Vasilyev, O., Oshanin, G.

Physical Review E, 87(6), American Physical Society, Melville, NY, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Critical Casimir forces between homogeneous and chemically striped surfaces

Parisen Toldin, F., Tröndle, M., Dietrich, S.

Physical Review E, 88, American Physical Society, Melville, NY, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Comparison between theory and simulations for the magnetization and the susceptibility of polydisperse ferrofluids

Szalai, I., Nagy, S., Dietrich, S.

Journal of Physics: Condensed Matter, 25(46), IOP Pub., Bristol, UK, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Thermal activation of catalytic microjets in blood samples using microfluidic chips.

Soler, L., Mart\’\inez-Cisneros, C., Swiersy, A., Sanchez, S., Schmidt, O. G.

Lab on a Chip, 13, pages: 4299-4303, 2013 (article)

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DOI [BibTex]


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Nematic liquid crystal boojums with handles on colloidal handlebodies

Liu, Q. K., Senyuk, B., Tasinkevych, M., Smalyukh, I. I.

Proceedings of the National Academy of Sciences of the United States of America, 110(23):9231-9236, National Academy of Sciences, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Critical Casimir torques and forces acting on needles in two spatial dimensions

Vasilyev, Oleg, Eisenriegler, E., Dietrich, Siegfried

Physical Review E, 88(1), American Physical Society, Melville, NY, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Critical Casimir forces along the isofields

Zubaszewska, M., Maciolek, A., Drzewinski, A.

Physical Review E, 88(5), American Physical Society, Melville, NY, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Surface states and the Casimir interaction in the Ising model

Abraham, D. B., Maciolek, A.

Europhysics letters, 101(2), Editrice Compositori., Bologna, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Crystallization, structural diversity, and anisotropy effects in 2D arrays of icosahedral viruses

Fukuto, M., Nguyen, Q. L., Vasilyev, O., Mank, N., Washington-Huges, C. L., Kuzmenko, I., Checco, A., Mao, Y., Wang, Q., Yang, L.

Soft Matter, 9(40):9633-9642, Royal Society of Chemistry, Cambridge, UK, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Dynamic arrest in model porous media-intermediate scattering functions

Spanner, Markus, Schnyder, Simon K., Höfling, Felix, Voigtmann, Thomas, Franosch, Thomas

Soft Matter, 9(5):1604-1611, Royal Society of Chemistry, Cambridge, UK, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Linear response relations in fluctuational electrodynamics

Golyk, V. A., Krüger, Matthias, Kardar, M.

Physical Review B, 88(15), American Physical Society, Woodbury, NY, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Ideal Polyethylene Nanocrystals

Osichov, A., Rabe, C., Vogtt, K., Narayanan, T., Harnau, Ludger, Drechsler, M., Ballauff, M.

Journal of the American Chemical Society, 135(31):11645-11650, American Chemical Society, 2013 (article)

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DOI [BibTex]


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Self-Assembly of Two-Dimensional Colloidal Clusters by Tuning the Hydrophobicity, Composition, and Packing Geometry

Law, A. D., Auriol, M., Smith, D., Horozov, T. S., Buzza, D. M. A.

Physical Review Letters, 110, American Physical Society., Woodbury, N.Y., etc., 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Geometry-Induced Superdiffusion in Driven Crowded Systems

Bénichou, O., Bodrova, A., Chakraborty, D., Illien, P., Law, A. D., Mej\’\ia-Monasterio, C., Oshanin, G., Voituriez, R.

Physical Review Letters, 111(26), American Physical Society, Woodbury, N.Y., 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Overshoots in stress-strain curves: Colloid experiments and schematic mode coupling theory

Amann, Christian P, Siebenbürger, Miriam, Krüger, Matthias, Weysser, Fabian, Ballauff, Matthias, Fuchs, Matthias

Journal of Rheology, 57, pages: 149-175, 2013 (article)

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DOI [BibTex]

DOI [BibTex]


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Wetting in electrolyte solutions

Ibagon, Ingrid, Bier, Markus, Dietrich, Siegfried

The Journal of Chemical Physics, 138(21), American Institute of Physics, Woodbury, N.Y., 2013 (article)

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DOI [BibTex]

2007


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Monte Carlo simulation results for critical Casimir forces

Vasilyev, O., Gambassi, A., Maciolek, A., Dietrich, S.

EPL, 80, 2007 (article)

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DOI [BibTex]

2007


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Critical Casimir effect in superfluid wetting films

Maciolek, A., Gambassi, A., Dietrich, S.

Physical Review E, 76, 2007 (article)

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DOI [BibTex]


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Complete wetting of pits and grooves

Tasinkevych, M., Dietrich, S.

European Physical Journal e: Soft Matter, 23(1):117-128, 2007 (article)

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[BibTex]

[BibTex]


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Experimental observation of structural crossover in binary mixtures of colloidal hard spheres

Baumgartl, J., Dullens, R. P. A., Dijkstra, M., Roth, R., Bechinger, C.

Physical Review Letters, 98, 2007 (article)

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DOI [BibTex]


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Physical basis for characterizing native structures of proteins

Harano, Y., Roth, R., Sugita, Y., Ikeguchi, M., Kinoshita, M.

Chemical Physics Letters, 437(1 - 3):112-116, 2007 (article)

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[BibTex]


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Importance of boundary conditions for fluctuation-induced forces between colloids at interfaces

Lehle, H., Oettel, M.

Physical Review E, 75(1), 2007 (article)

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[BibTex]


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Colloid-colloid and colloid-wall interactions in driven suspensions

Krüger, M., Rauscher, M.

The Journal of Chemical Physics, 127(3), 2007 (article)

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DOI [BibTex]


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Solvation of proteins: linking thermodynamics to geometry

Hansen-Goos, H., Roth, R., Mecke, K., Dietrich, S.

Physical Review Letters, 99, 2007 (article)

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DOI [BibTex]

DOI [BibTex]