ALBERT

Description:    The effect of strain accumulation in the InAs/In x Ga 1− x As quantum dots (QDs) system was studied in this work. It was found that strain in the In x Ga 1− x As layer accumulation in the QD layer. This effect resulted in a dramatic reduction of growth mode transition thickness of the QD layer. For InAs/In 0.25 Ga 0.75 As QDs, critical thickness is measured to be as low as 1.08 ML. The experimental results in this work highlight the importance of strain accumulation in the design and fabrication of QD-based devices with metamorphic buffer layer involved. Content Type Journal Article Pages 1-6 DOI 10.1007/s00339-011-6482-1 Authors Lu Wang, National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China Meicheng Li, School of Renewable Energy, North China Electric Power University, Beijing, 102206 China Wenxin Wang, National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China Haitao Tian, National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China Zhigang Xing, National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China Min Xiong, School of Material Science and Technology, Harbin Institute of Technology, Harbin, China Liancheng Zhao, School of Material Science and Technology, Harbin Institute of Technology, Harbin, China Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    The strong influence of laser polarization on the orientation and shape of femtosecond-laser-induced self-organized nanostructures (‘ripples’, LIPSS) still constitutes an open question, taking into account that the laser electric field is present only at the first step of electronic excitation. Based on the explanation of similar structures generated during ion sputtering, we present a theoretical model indicating a possible explanation for this phenomenon. Our model shows that a directional asymmetry in the pattern can result from a spatial asymmetry of the initial excitation, induced e.g. by a corresponding distribution of excited-electron kinetic energies. Numerical simulation of this model yields typical patterns which are compared to experimental observations under appropriate conditions. Content Type Journal Article Pages 1-5 DOI 10.1007/s00339-011-6472-3 Authors Juergen Reif, Experimental Physics II/Materials Science, Brandenburgische Technische Universität (BTU) Cottbus, Universitätsstr. 1, 03046 Cottbus, Germany Olga Varlamova, Experimental Physics II/Materials Science, Brandenburgische Technische Universität (BTU) Cottbus, Universitätsstr. 1, 03046 Cottbus, Germany Sergej Varlamov, Statistical Physics and Nonlinear Dynamics, Brandenburgische Technische Universität (BTU) Cottbus, Universitätsstr. 1, 03046 Cottbus, Germany Michael Bestehorn, Statistical Physics and Nonlinear Dynamics, Brandenburgische Technische Universität (BTU) Cottbus, Universitätsstr. 1, 03046 Cottbus, Germany Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    The preparation of chlorine-, bromine-, and iodine-terminated silicon surfaces (Si(111):Cl, Br, and I) using atomically flat Si(111)-(1×1):H is described. The halogenated surfaces were obtained by photochemically induced radical substitution reactions with the corresponding dihalogen in a Schlenk tube by conventional inert gas chemistry. The nucleophilic substitution of the Si-Cl functionality with the Grignard reagent (CH 3 MgCl) resulted in the unreconstructed methylated Si(111)-(1×1):CH 3 surface. The halogenated and methylated silicon surfaces were characterized by Fourier transform infrared (FTIR) spectroscopy and laser-induced desorption of monolayers (LIDOM). Calibration of the desorption temperature via analysis of time-of-flight (TOF) distributions as a function of laser fluence allowed the determination of the originally emitted neutral fragments by TOF mass spectrometry using electron-impact ionization. The halogens were desorbed atomically and as SiX n (X = Cl, Br) clusters. The methyl groups mainly desorbed as methyl and ethyl fragments and a small amount of + SiCH 3 . Content Type Journal Article Pages 1-5 DOI 10.1007/s00339-011-6483-0 Authors Nils Salingue, Institute of Physical Chemistry, University of Heidelberg, 69120 Heidelberg, Germany Peter Hess, Institute of Physical Chemistry, University of Heidelberg, 69120 Heidelberg, Germany Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    This paper investigates the flow field near three intersecting shock waves appearing in steady Mach reflection. Results of numerical computations reveal a “von Neumann Paradox”—like feature for weak shock waves, in which the flow field between the reflected and the Mach stem is smooth with no distinct slip flow region and changes rather smoothly. An analytical solution of the Navier–Stokes equations constructed using a polar–coordinate system gives a flow field with the same properties as the numerical simulation. Content Type Journal Article Pages 1-6 DOI 10.1007/s00193-011-0329-8 Authors A. Sakurai, Tokyo Denki University, Kanda, Tokyo, Japan M. Tsukamoto, Tokyo Denki University, Kanda, Tokyo, Japan D. Khotyanovsky, Institute of Theoretical and Applied Mechanics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia M. Ivanov, Institute of Theoretical and Applied Mechanics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia Journal Shock Waves Online ISSN 1432-2153 Print ISSN 0938-1287

Description:    The propagation and attenuation of an initial shock wave through a mm-scale channel of circular cross-section over lengths up to 2,000 diameters is examined as a model problem for the scaling of viscous effects in compressible flows. Experimental wave velocity measurements and pressure profiles are compared with existing data and theoretical predictions for shock attenuation at large scales and low pressures. Significantly more attenuation is observed than predicted based on streamtube divergence. Simulations of the experiment show that viscous effects need to be included, and the boundary layer behavior is important. A numerical model including boundary layer and channel entrance effects reproduces the wave front velocity measurements, provided a boundary layer transition model is included. A significant late-time pressure rise is observed in experiments and in the simulations. Content Type Journal Article Pages 1-11 DOI 10.1007/s00193-011-0330-2 Authors J. M. Austin, Department of Aerospace Engineering, University of Illinois, Urbana, IL 61801, USA D. J. Bodony, Department of Aerospace Engineering, University of Illinois, Urbana, IL 61801, USA Journal Shock Waves Online ISSN 1432-2153 Print ISSN 0938-1287

Description: Erratum to: The Role of Tortuosity in Upscaling Content Type Journal Article Pages 1-3 DOI 10.1007/s11242-011-9787-9 Authors Francisco J. Valdés-Parada, Area de Ingeniería en Recursos Energéticos, Universidad Autónoma Metropolitana-Iztapalapa, Mexico, D.F. 09340, Mexico Mark L. Porter, EES-14, MS D462, Los Alamos National Laboratory, Los Alamos, NM 87545, USA Brian D. Wood, School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA Journal Transport in Porous Media Online ISSN 1573-1634 Print ISSN 0169-3913

Description:    We have demonstrated spatially selective modification of the magnetic properties of transparent iron-oxide-doped glass by femtosecond- (fs-) laser irradiation and subsequent annealing. A near-infrared fs-laser beam with a wavelength of 775 nm was focused 1 mm below the surfaces of glass samples. This produces absorption peaks due to the formation of hole-trap centers in the irradiated region. Transparency was recovered after annealing at 450°C. A ferrimagnetic component was observed in the M–H curve even at room temperature, whereas the diamagnetic component dominated in the M–H curve of the as-prepared glass sample. This indicates that fs-laser irradiation enhanced the magnetization in the irradiated area. The irradiated and annealed glass sample also exhibited superparamagnetic blocking in the temperature dependence of the magnetization with a blocking temperature higher than room temperature. This change in magnetism is presumably due to local crystallization of ferrimagnetic nanoparticles, such as magnetite, induced by fs-laser irradiation and annealing. The magnetic and optical properties of glass that had been annealed but not irradiated by a fs-laser beam remained unchanged. Content Type Journal Article Pages 1-4 DOI 10.1007/s00339-011-6485-y Authors Seisuke Nakashima, RIKEN—Advanced Science Institute, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan Koji Sugioka, RIKEN—Advanced Science Institute, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan Katsumi Midorikawa, RIKEN—Advanced Science Institute, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    In this paper, we demonstrate that cubic gadolinium oxide is paramagnetic and follows the Curie–Weiss law from 20 K to room temperature for particles size comprised between 3.5 and 60 nm. The largest particles (60 nm) possess the macroscopic behaviour of Gd oxide with a Néel temperature, T N , close to 18 K (Gd oxide is antiferromagnetic below T N , paramagnetic above). Then size-induced effects can be encountered only for particles smaller than 60 nm. We find that the finite-size scaling model used for describing the size evolution of the antiferro/paramagnetic transition is valid for sizes comprised between 3.5 and 35 nm with parameters in excellent agreement with those usually found for antiferromagnetic materials. The correlation length (3.6 nm) is of the order of magnitude of a few lattice parameters and the critical exponent λ is found equal to 1.3, a value very close to that predicted by the three dimensional Heisenberg model ( λ =1.4). Content Type Journal Article Pages 1-5 DOI 10.1007/s00339-011-6492-z Authors B. Mutelet, MATEIS, UMR 5510 CNRS, Université de Lyon, INSA-Lyon, 20 av. Albert Einstein, 69621 Villeurbanne Cedex, France N. Keller, GEMAC, UMR 8635 CNRS, Université de Versailles-St-Quentin, 45, avenue des Etats-Unis, 78035 Versailles Cedex, France S. Roux, UTINAM, UMR 6213 CNRS, Université de Franche-Comté, 25030 Besanon Cedex, France M. A. Flores-Gonzales, LPCML, Université de Lyon, Université Claude Bernard, 43 Bd du 11 novembre 1918, 69622 Villeurbanne Cedex, France F. Lux, LPCML, Université de Lyon, Université Claude Bernard, 43 Bd du 11 novembre 1918, 69622 Villeurbanne Cedex, France M. Martini, MATEIS, UMR 5510 CNRS, Université de Lyon, INSA-Lyon, 20 av. Albert Einstein, 69621 Villeurbanne Cedex, France O. Tillement, LPCML, Université de Lyon, Université Claude Bernard, 43 Bd du 11 novembre 1918, 69622 Villeurbanne Cedex, France C. Billotey, LPCML, Université de Lyon, Université Claude Bernard, 43 Bd du 11 novembre 1918, 69622 Villeurbanne Cedex, France M. Janier, LPCML, Université de Lyon, Université Claude Bernard, 43 Bd du 11 novembre 1918, 69622 Villeurbanne Cedex, France C. Villiers, INSERM U823, Institut Albert Bonniot, Rond Point de la Chantourne, 38574 La Tronche, France Ghenadie Novitchi, Laboratoire des Multimatériaux et Interfaces, Université de Lyon, Université Claude Bernard, 3 Bd du 11 novembre 1918, 69622 Villeurbanne Cedex, France Dominique Luneau, Laboratoire des Multimatériaux et Interfaces, Université de Lyon, Université Claude Bernard, 3 Bd du 11 novembre 1918, 69622 Villeurbanne Cedex, France P. Perriat, MATEIS, UMR 5510 CNRS, Université de Lyon, INSA-Lyon, 20 av. Albert Einstein, 69621 Villeurbanne Cedex, France Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    Pore networks can be extracted from 3D rock images to accurately predict multi-phase flow properties of rocks by network flow simulation. However, the predicted flow properties may be sensitive to the extracted pore network if it is small, even though its underlying characteristics are representative. Therefore, it is a challenge to investigate the effects on flow properties of microscopic rock features individually and collectively based on small samples. In this article, a new approach is introduced to generate from an initial network a stochastic network of arbitrary size that has the same flow properties as the parent network. Firstly, we characterise the realistic parent network in terms of distributions of the geometrical pore properties and correlations between these properties, as well as the connectivity function describing the detailed network topology. Secondly, to create a stochastic network of arbitrary size, we generate the required number of nodes and bonds with the correlated properties of the original network. The nodes are randomly located in the given network domain and connected by bonds according to the strongest correlation between node and bond properties, while honouring the connectivity function. Thirdly, using a state-of-the-art two-phase flow network model, we demonstrate for two samples that the rock flow properties (capillary pressure, absolute and relative permeability) are preserved in the stochastic networks, in particular, if the latter are larger than the original, or the method reveals that the size of the original sample is not representative. We also show the information that is necessary to reproduce the realistic networks correctly, in particular the connectivity function. This approach forms the basis for the stochastic generation of networks from multiple rock images at different resolutions by combining the relevant statistics from the corresponding networks, which will be presented in a future publication. Content Type Journal Article Pages 1-23 DOI 10.1007/s11242-011-9792-z Authors Z. Jiang, Institute of Petroleum Engineering, Heriot-Watt University, Edinburgh, EH14 4AS UK M. I. J. van Dijke, Institute of Petroleum Engineering, Heriot-Watt University, Edinburgh, EH14 4AS UK K. Wu, Institute of Petroleum Engineering, Heriot-Watt University, Edinburgh, EH14 4AS UK G. D. Couples, Institute of Petroleum Engineering, Heriot-Watt University, Edinburgh, EH14 4AS UK K. S. Sorbie, Institute of Petroleum Engineering, Heriot-Watt University, Edinburgh, EH14 4AS UK J. Ma, Institute of Petroleum Engineering, Heriot-Watt University, Edinburgh, EH14 4AS UK Journal Transport in Porous Media Online ISSN 1573-1634 Print ISSN 0169-3913

Description:    Surface ablation of a dielectric material (fused silica) by single femtosecond pulses is studied as a function of pulse duration (7–450 fs) and applied fluence ( F th 〈 F 〈10 F th ). We show that varying the pulse duration gives access to high selectivity (with resolution ∼10 nm) for axial removal of matter but does not influence the transverse ablation selectivity, which only depends on the normalized applied fluence F / F th . The ablation efficiency is shown to be inversely dependent on the pulse duration and saturates with respect to the applied fluence earlier at ultra-short pulse durations (≤30 fs). The deduced optimal fluence F opt corresponding to the highest ablation efficiency for each pulse width defines two regimes of laser application. Below F opt , the removed material depth can be accurately adjusted in a large range (∼40–200 nm) as a function of the applied fluence and the morphology of the ablated pattern almost reproduces the Gaussian beam distribution. Above F opt , the material removal depth tends to saturate and the morphology of the ablated pattern evolves to a top-hat distribution. The coupled evolution of depth and morphology is related to the dynamics of formation of dense plasma at the surface of the material, acting as an ultra-fast optical shutter. Content Type Journal Article Pages 1-11 DOI 10.1007/s00339-011-6469-y Authors O. Utéza, Laboratoire LP3, UMR 6182 CNRS-Aix-Marseille Université, C. 917, 163 Avenue de Luminy, 13288 Marseille Cedex 9, France N. Sanner, Laboratoire LP3, UMR 6182 CNRS-Aix-Marseille Université, C. 917, 163 Avenue de Luminy, 13288 Marseille Cedex 9, France B. Chimier, Laboratoire LP3, UMR 6182 CNRS-Aix-Marseille Université, C. 917, 163 Avenue de Luminy, 13288 Marseille Cedex 9, France A. Brocas, Laboratoire LP3, UMR 6182 CNRS-Aix-Marseille Université, C. 917, 163 Avenue de Luminy, 13288 Marseille Cedex 9, France N. Varkentina, Laboratoire LP3, UMR 6182 CNRS-Aix-Marseille Université, C. 917, 163 Avenue de Luminy, 13288 Marseille Cedex 9, France M. Sentis, Laboratoire LP3, UMR 6182 CNRS-Aix-Marseille Université, C. 917, 163 Avenue de Luminy, 13288 Marseille Cedex 9, France P. Lassonde, Energie, Matériaux et Télécommunications, INRS, 1650 Boulevard Lionel Boulet, Varennes, Québec J3X 1S2, Canada F. Légaré, Energie, Matériaux et Télécommunications, INRS, 1650 Boulevard Lionel Boulet, Varennes, Québec J3X 1S2, Canada J. C. Kieffer, Energie, Matériaux et Télécommunications, INRS, 1650 Boulevard Lionel Boulet, Varennes, Québec J3X 1S2, Canada Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    An energy source produced by a TEA CO 2 laser operated at 10.6 μm primarily was considered as a key essential in this paper to describe the energy conversion process in air-breathing laser propulsion in the round. Some secondary factors were ignored when three independent modules, a ray transmission module, an energy source term module and a fluid mechanics module, were established by a simultaneous laser radiation transportation equation and a fluid mechanics equation set-up. The incident laser beam after being reflected by the optical system or transmitted by it was simulated based on a certain geometrical optics method named ray tracing. Thus, coherent superimposition could be avoided when describing the laser beam focusing process, and so could the solving process of the laser wave equation at the non-paraxial condition. The calculated results were in good agreement with those of theoretical analysis and experiments. Content Type Journal Article Pages 1-8 DOI 10.1007/s00339-011-6479-9 Authors Yanji Hong, Academy of Equipment Command & Technology, Post Box 3380-86, Huairou District, Beijing, 101416 China Junling Song, Academy of Equipment Command & Technology, Post Box 3380-86, Huairou District, Beijing, 101416 China Cunyan Cui, Academy of Equipment Command & Technology, Post Box 3380-86, Huairou District, Beijing, 101416 China Qian Li, Academy of Equipment Command & Technology, Post Box 3380-86, Huairou District, Beijing, 101416 China Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    Engineering design of thermal quality clothing is a promising solution by applying multi-disciplinary knowledge to achieve the design and production of clothing with desirable thermal functions. In this paper, a special simulation-based and lifestyle-oriented CAD system is introduced to help the user in engineering design of thermal quality clothing. The engineering-oriented simulation models endowed with explicit data availability arose from the material parameters that are the key issue for engineering application. To offer an easy-to-use tool, this system is implemented with a lifestyle-oriented design procedure. It can facilitate the designers to quickly implement design and simulate on the wearing scenario, and evaluate and optimize their design. Due to the design of thermal quality clothing can be achieved without making physical prototypes, it is able to speed up the design cycle and reduce the design and development cost. Content Type Journal Article Pages 1-17 DOI 10.1007/s00366-011-0224-z Authors Aihua Mao, School of Computer Science and Engineering, South China University of Technology, Guangzhou, 510006 China Jie Luo, Institute of Textiles and Clothing, Hong Kong Polytechnic University, Hung Hom, Hong Kong, China Yi Li, Institute of Textiles and Clothing, Hong Kong Polytechnic University, Hung Hom, Hong Kong, China Ruomei Wang, School of Information Science and Technology, Sun Yat-Sen University, Guangzhou, 510006 China Guiqing Li, School of Computer Science and Engineering, South China University of Technology, Guangzhou, 510006 China Yueping Guo, Institute of Textiles and Clothing, Hong Kong Polytechnic University, Hung Hom, Hong Kong, China Journal Engineering with Computers Online ISSN 1435-5663 Print ISSN 0177-0667

Description:    Understanding the mechanical properties of ancient paintings is a major issue for conservation and restoration. One strategy is to measure the mechanical properties of reconstructed paints: however, the aging process is poorly known, so it is also desirable to measure mechanical properties directly on ancient paint samples. Using nanoindentation, we have characterized submillimetric samples recovered from restoration of two Van Gogh paintings and compared the results with reconstructed paint samples. We demonstrate that the reduced modulus and hardness of historical paints can be measured at a very local scale, even differentiating between each paint layer. Our reconstructed paint samples exhibit elastic moduli comparable to values of the literature, but the values measured on the two 19th century paint samples are found to be significantly larger. Similarly, the compositional dependence of the elastic modulus is consistent with literature results for our reconstructed samples while our preliminary results for ancient samples do not readily fall into the same pattern. These results all point out to a significant impact of long term aging, in a manner which is difficult to predict in our present state of understanding. They demonstrate that nanoindentation is a very adequate tool to improve our knowledge of art paint mechanics and aging. Content Type Journal Article Pages 1-7 DOI 10.1007/s00339-011-6486-x Authors Johanna Salvant, Laboratoire du Centre de Recherche et de Restauration des Musées de France (C2RMF), CNRS UMR 171, Palais du Louvre, 14, Quai François Mitterrand, Paris, 75001 France Etienne Barthel, Laboratoire CNRS/Saint-Gobain “Surface du Verre et Interfaces”, UMR 125, 39, Quai Lucien Lefranc, BP 135, Aubervilliers Cedex, 93303 France Michel Menu, Laboratoire du Centre de Recherche et de Restauration des Musées de France (C2RMF), CNRS UMR 171, Palais du Louvre, 14, Quai François Mitterrand, Paris, 75001 France Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    The effect of HfO 2 on phase change characteristics of Sb 2 Te 3 films for phase change memory (PCM) applications was investigated by in situ temperature dependence of electrical resistance measurement, X-ray diffraction, field emission scanning electron microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy. It is shown that HfO 2 inhibited the crystallization of the amorphous Sb 2 Te 3 films, which improved the long-term stability of metastable amorphous phase. Memory devices based on Sb 2 Te 3 –HfO 2 composite films with HfO 2 concentrations of 10 at.% and 15 at.% were successfully fabricated and characterized. The 15 at.% HfO 2 -based memory device exhibited lower reset voltage and power consumption compared with the 10 at.% HfO 2 - and Ge 2 Sb 2 Te 5 -based ones. The endurances exceeded 1.6×10 5 and 2.2×10 5 SET–RESET cycles for 10 at.% and 15 at.% HfO 2 -based memory devices, respectively, and the resistance ratio between RESET and SET states achieved two orders of magnitude for both memory devices. The Sb 2 Te 3 –HfO 2 composite films, especially with HfO 2 concentration of 15 at.%, could be one of the most promising materials for application in PCM devices. Content Type Journal Article Pages 1-6 DOI 10.1007/s00339-011-6478-x Authors Yegang Lu, State Key Laboratory of Functional Materials for Informatics, Laboratory of Nanotechnology, Shanghai Institute of Micro-system and Information Technology, Chinese Academy of Sciences, Shanghai, 200050 China Sannian Song, State Key Laboratory of Functional Materials for Informatics, Laboratory of Nanotechnology, Shanghai Institute of Micro-system and Information Technology, Chinese Academy of Sciences, Shanghai, 200050 China Zhitang Song, State Key Laboratory of Functional Materials for Informatics, Laboratory of Nanotechnology, Shanghai Institute of Micro-system and Information Technology, Chinese Academy of Sciences, Shanghai, 200050 China Kun Ren, State Key Laboratory of Functional Materials for Informatics, Laboratory of Nanotechnology, Shanghai Institute of Micro-system and Information Technology, Chinese Academy of Sciences, Shanghai, 200050 China Bo Liu, State Key Laboratory of Functional Materials for Informatics, Laboratory of Nanotechnology, Shanghai Institute of Micro-system and Information Technology, Chinese Academy of Sciences, Shanghai, 200050 China Songlin Feng, State Key Laboratory of Functional Materials for Informatics, Laboratory of Nanotechnology, Shanghai Institute of Micro-system and Information Technology, Chinese Academy of Sciences, Shanghai, 200050 China Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    We investigated the ejection dynamics of triazene polymer layers in the thickness range of 40 nm to 600 nm upon nanosecond laser ablation at a wavelength of 532 nm. The ablation is due to laser-induced thermal degradation of a small part of the polymer in contact with the silicon substrate. The subsequent dynamics of the flying polymer layer are measured with sub-nanosecond time resolution. The evaluation of the initial velocity for different film thicknesses gives insight into the energy transfer process during the acceleration of the films. Content Type Journal Article Pages 1-4 DOI 10.1007/s00339-011-6500-3 Authors P. Frank, University of Konstanz, 78457 Konstanz, Germany J. Shaw-Stewart, Laboratory for Functional Polymers, EMPA, Swiss Federal Laboratories for Material Testing and Research, Überlandstrasse 129, 8600 Dübendorf, Switzerland T. Lippert, General Energy Research Department, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland J. Boneberg, University of Konstanz, 78457 Konstanz, Germany P. Leiderer, University of Konstanz, 78457 Konstanz, Germany Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    Spontaneous nanostructure formations on roughened and smooth silicon surface by the femtosecond laser irradiation with the repetition rate of 100 kHz were systematically studied. In addition to the widely accepted so-called coarse ripple, which has the period analogous to the wavelength of the laser beam and aligns perpendicularly to the electric field of the incident laser beam, the ripple which has the period similar to the wavelength of the incident laser beam but aligns parallel to the electric field of the laser beam was observed on the roughened surface for the lower fluence and the higher number of pulse irradiation. Furthermore, the ensemble of dots formed by the enhancement of the local electric field was found on the roughened surface. This structure is preferentially formed around the scratches aligned perpendicularly to the electric field of the laser beam. These novel nanostructures are considered to be peculiar to the femtosecond laser irradiation and open the possibilities for precise control of the spontaneous nanostructure formation by femtosecond laser irradiation. Content Type Journal Article Pages 1-6 DOI 10.1007/s00339-011-6490-1 Authors Takuro Tomita, Department of Ecosystem Engineering, The University of Tokushima, Tokushima, 770-8506 Japan Ryota Kumai, Department of Ecosystem Engineering, The University of Tokushima, Tokushima, 770-8506 Japan Hidenori Nomura, Department of Ecosystem Engineering, The University of Tokushima, Tokushima, 770-8506 Japan Shigeki Matsuo, Department of Ecosystem Engineering, The University of Tokushima, Tokushima, 770-8506 Japan Shuichi Hashimoto, Department of Ecosystem Engineering, The University of Tokushima, Tokushima, 770-8506 Japan Ken Morita, Center for Frontier Research of Engineering, The University of Tokushima, Tokushima, 770-8506 Japan Toshiro Isu, Center for Frontier Research of Engineering, The University of Tokushima, Tokushima, 770-8506 Japan Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    We present a study of the temperature non-homogeneities induced by millisecond laser annealing in advanced CMOS technologies at die level. Because of the design, the device layout at the wafer surface introduces during this anneal significant spatial variations of optical absorption and heat transfer that can induce temperature non-uniformities over the die, often called ‘pattern effects’. These temperature variations are becoming a major issue, since they are the origin of significant device properties dispersion. A complete optical and thermal simulation set has been developed to estimate the temperature variations induced by the topologies at the wafer surface during the laser anneal process. The modelling has been validated by either a comparison with another software or reflectometry and electrical measurements on real structures. This work demonstrates that the temperature variations are caused either by optical coupling or by thermal properties dispersion present at the wafer surface at the anneal step. Finally, we demonstrate that the impact of the thin-film interferences and diffraction phenomena is the critical issue for these pattern effects. Content Type Journal Article Pages 1-11 DOI 10.1007/s00339-011-6467-0 Authors A. Colin, STMicroelectronics, 850 rue Jean Monnet, 38926 Crolles Cedex, France P. Morin, STMicroelectronics, 850 rue Jean Monnet, 38926 Crolles Cedex, France F. Cacho, STMicroelectronics, 850 rue Jean Monnet, 38926 Crolles Cedex, France H. Bono, LETI, CEA-Grenoble, 17 Rue des Martyrs, 38054 Grenoble Cedex 9, France R. Beneyton, STMicroelectronics, 850 rue Jean Monnet, 38926 Crolles Cedex, France D. Mathiot, InESS, CNRS and Université de Strasbourg, BP 20 CR, 23 rue de Loess, 67037 Strasbourg Cedex 2, France E. Fogarassy, InESS, CNRS and Université de Strasbourg, BP 20 CR, 23 rue de Loess, 67037 Strasbourg Cedex 2, France Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    A micro-crack in silicon was experimentally investigated by using a combination of transmission electron microscopy and geometric phase analysis. The strain fields of the crack tip, with scales of a few tens of nanometers, were mapped. The crack tip dislocation emission and stress relief by dislocation generation around a crack tip can be proved. And, the strain field of an edge dislocation was compared with the Peierls–Nabarro dislocation model at the scale of a dislocation width. We show that the Peierls–Nabarro model is the appropriate theoretical model to describe the deformation fields of the dislocation core. Content Type Journal Article Pages 1-4 DOI 10.1007/s00339-011-6488-8 Authors C. W. Zhao, College of Science, Inner Mongolia University of Technology, Hohhot, 010051 China Y. M. Xing, College of Science, Inner Mongolia University of Technology, Hohhot, 010051 China P. C. Bai, College of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot, 010051 China J. J. Li, College of Science, Inner Mongolia University of Technology, Hohhot, 010051 China Q. L. Liu, College of Science, Inner Mongolia University of Technology, Hohhot, 010051 China Y. G. Du, College of Science, Inner Mongolia University of Technology, Hohhot, 010051 China M. H. Liu, College of Science, Inner Mongolia University of Technology, Hohhot, 010051 China Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    Thin films of the n-type, organic semiconductor PDI-8CN 2 were thermally evaporated on two different dielectric surfaces and their optical and morphological properties investigated using Variable Angle Spectroscopic Ellipsometry (VASE) and Atomic Force Microscopy (AFM), respectively. The two dielectric surfaces used were SiO 2 and a plasma polymer derived from the non-synthetic monomer linalyl acetate. The characterisations were performed in order to assess the viability of plasma polymerised linalyl acetate (PLA) thin films as dielectric layers in future Organic Field-Effect Transistor (OFET) devices. These studies resulted in determination of the optical profiles (refractive index and extinction coefficient) in the UV-Vis band of PDI-8CN 2 grown on SiO 2 and an observation of uniaxial anisotropy in the organic semiconductor. This information is useful for the design of opto-electronic devices using PDI-8CN 2 layers. Variations in morphological properties and small variations optical properties were found when the PDI-8CN 2 films were grown on PLA layers, and attributed to the change in surface chemistry between dielectrics. Content Type Journal Article Pages 1-8 DOI 10.1007/s00339-011-6487-9 Authors L. J. Anderson, Electronic Materials Research Lab, School of Engineering and Physical Sciences, James Cook University, Townsville, QLD 4811 Australia M. V. Jacob, Electronic Materials Research Lab, School of Engineering and Physical Sciences, James Cook University, Townsville, QLD 4811 Australia M. Barra, CNR-SPIN and Department of Physics Science, University of Naples Federico II, Piazzale Tecchio 80125 Naples, Italy F. V. Di Girolamo, CNR-SPIN and Department of Physics Science, University of Naples Federico II, Piazzale Tecchio 80125 Naples, Italy A. Cassinese, CNR-SPIN and Department of Physics Science, University of Naples Federico II, Piazzale Tecchio 80125 Naples, Italy Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    Thermophysical properties of liquid alloys are usually difficult to measure, especially for high melting point and reactive alloys. In this work, the surface tensions of superheated and undercooled liquid Ti 55 Al 45 , Ti 50 Al 45 Nb 5 and Ti 45 Al 45 Nb 10 alloys are determined by using oscillating drop method under electromagnetic levitation state. The experimental results of Ti–Al and Ti–Al–Nb alloys display linear temperature dependence. The maximum undercoolings of 259 (0.143 T L ), 268 (0.146 T L ) and 275 K (0.147 T L ) are respectively achieved for these three alloys. Furthermore, the viscosities of liquid Ti 55− x Al 45 Nb x alloys are also derived from the experimental results. Content Type Journal Article Pages 1-4 DOI 10.1007/s00339-011-6491-0 Authors K. Zhou, Department of Applied Physics, Northwestern Polytechnical University, Xi’an, 710072 People’s Republic of China H. P. Wang, Department of Applied Physics, Northwestern Polytechnical University, Xi’an, 710072 People’s Republic of China J. Chang, Department of Applied Physics, Northwestern Polytechnical University, Xi’an, 710072 People’s Republic of China B. Wei, Department of Applied Physics, Northwestern Polytechnical University, Xi’an, 710072 People’s Republic of China Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    We present an object-oriented framework, named DOOLINES , for non-linear static and dynamic analyses of slender marine structures which often appear in offshore structures employed in the petroleum and gas industries as, among others, flexible risers, steel catenary risers, umbilicals, floating hoses, and mooring lines. DOOLINES allows the rapid development of tailored, modular, reusable and extensible large-size systems, being itself extensible. These properties, along with the ease of use of our framework, are assessed by means of case studies. Code examples are provided. Content Type Journal Article Pages 1-11 DOI 10.1007/s00366-011-0226-x Authors Eduardo S. S. da Silveira, Laboratório de Computação Científica e Visualização, Universidade Federal de Alagoas, Campus A. C. Simões, Av. Lourival de Melo Mota S/N, Tabuleiro do Martins, 57072-970 Maceió, AL, Brazil Eduardo N. Lages, Laboratório de Computação Científica e Visualização, Universidade Federal de Alagoas, Campus A. C. Simões, Av. Lourival de Melo Mota S/N, Tabuleiro do Martins, 57072-970 Maceió, AL, Brazil Fábio M. G. Ferreira, Laboratório de Computação Científica e Visualização, Universidade Federal de Alagoas, Campus A. C. Simões, Av. Lourival de Melo Mota S/N, Tabuleiro do Martins, 57072-970 Maceió, AL, Brazil Journal Engineering with Computers Online ISSN 1435-5663 Print ISSN 0177-0667

Description:    We consider the effects of rotation in a mushy layer being cast from a vertical surface where the effects of Coriolis acceleration, gravity and centrifugal effects are included. It is demonstrated that the Coriolis acceleration and gravity play a passive role in convection and are excluded from the stability criteria. The stability criteria is presented as the critical centrifugal Rayleigh numbers referenced for locations far away (start of solidification) and close to (nearing end of solidification) the axis or rotation. Content Type Journal Article Pages 1-10 DOI 10.1007/s11242-011-9790-1 Authors S. Govender, Corporate Specialist Gas Turbines, Generation Business Engineering, ESKOM Holdings Ltd., Maxwell Drive Sunninghill, Johannesburg, 2000 South Africa Journal Transport in Porous Media Online ISSN 1573-1634 Print ISSN 0169-3913

Description:    The onset of thermal convection in a two-dimensional porous box is investigated analytically. One of the two lateral boundaries is in contact with a hydrostatic reservoir, where the saturating fluid can flow freely in and out. This open boundary is thermally insulating, but with the buoyancy of the fluid taken into account. For the second lateral wall, we study five different options for the boundary conditions. This leads to five different eigenvalue problems for the onset of convection. These five solutions are compared with the known solutions where the buoyancy along open sidewalls is neglected (Tyvand 2002 ). Content Type Journal Article Pages 1-18 DOI 10.1007/s11242-011-9791-0 Authors Heidi S. Nygård, Department of Mathematical Sciences and Technology, Norwegian University of Life Sciences, Ås, 1432 Norway Peder A. Tyvand, Department of Mathematical Sciences and Technology, Norwegian University of Life Sciences, Ås, 1432 Norway Journal Transport in Porous Media Online ISSN 1573-1634 Print ISSN 0169-3913

Description:    Image-based network modeling has become a powerful tool for modeling transport in real materials that have been imaged using X-ray computed micro-tomography (XCT) or other three-dimensional imaging techniques. Network generation is an essential part of image-based network modeling, but little quantitative work has been done to understand the influence of different network structures on modeling. We use XCT images of three different porous materials (disordered packings of spheres, sand, and cylinders) to create a series of four networks for each material. Despite originating from the same data, the networks can be made to vary over two orders of magnitude in pore density, which in turn affects network properties such as pore-size distribution and pore connectivity. Despite the orders-of-magnitude difference in pore density, single-phase permeability predictions remain remarkably consistent for a given material, even for the simplest throat conductance formulas. Detailed explanations for this beneficial attribute are given in the article; in general, it is a consequence of using physically representative network models. The capillary pressure curve generated from quasi-static drainage is more sensitive to network structure than permeability. However, using the capillary pressure curve to extract pore-size distributions gives reasonably consistent results even though the networks vary significantly. These results provide encouraging evidence that robust network modeling algorithms are not overly sensitive to the specific structure of the underlying physically representative network, which is important given the variety image-based network-generation strategies that have been developed in recent years. Content Type Journal Article Pages 1-29 DOI 10.1007/s11242-011-9789-7 Authors Pradeep Bhattad, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA 70803, USA Clinton S. Willson, Department of Civil and Environmental Engineering, Louisiana State University, Baton Rouge, LA 70803, USA Karsten E. Thompson, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA 70803, USA Journal Transport in Porous Media Online ISSN 1573-1634 Print ISSN 0169-3913

Description:    Low salinity water injections for oil recovery have shown seemingly promising results in the case of clay-bearing sandstones saturated with asphaltic crude oil. Reported data showed that low salinity water injection could provide up to 20% pore volume (PV) of additional oil recovery for core samples and up to 25% PV for reservoirs in near wellbore regions, compared with brine injection at the same Darcy velocity. The question remains as to whether this additional recovery is also attainable in reservoirs. The answer requires a thorough understanding of oil recovery mechanism of low salinity water injections. Numerous hypotheses have been proposed to explain the increased oil recovery using low salinity water, including migration of detached mixed-wet clay particles with absorbed residual oil drops, wettability alteration toward increased water-wetness, and emulsion formation. However, many later reports showed that a higher oil recovery associated with low salinity water injection at the common laboratory flow velocity was neither necessarily accompanied by migration of clay particles, nor necessarily accompanied by emulsion. Moreover, increased water-wetness has been shown to cause the reduction of oil recovery. The present study is based on both experimental and theoretical analyses. Our study reveals that the increased oil recovery is only related to the reduction of water permeability due to physical plugging of the porous network by swelling clay aggregates or migrating clay particles and crystals. At a fixed apparent flow velocity, the value of negative pressure gradient along the flow path increases as the water permeability decreases. Some oil drops and blobs can be mobilized under the increased negative pressure gradient and contribute to the additional oil recovery. Based on the revealed mechanism, we conclude that low salinity water injection cannot be superior to brine injection in any clay-bearing sandstone reservoir at the maximum permitted injection pressure. Through our study of low salinity water injection, the theory of tertiary oil recovery has been notably improved. Content Type Journal Article Pages 1-30 DOI 10.1007/s11242-011-9788-8 Authors Y. Li, Department of Chemical and Petroleum Engineering, University of Wyoming, Laramie, WY 82071, USA Journal Transport in Porous Media Online ISSN 1573-1634 Print ISSN 0169-3913

Description:    Existing non-Gaussian closure method is usually applied to non-linear systems with white noise excitation only. But random vibration of vehicle is excited by correlated road spectrum. To solve vibration responses of a non-linear automotive suspension system, the non-Gaussian closure solution procedure is improved by introducing an additional subsystem which described by a simple differential equation to the vehicle model. A car model with two degrees of freedom against three different types of damping is analyzed based on this proposed method. Some important parameters such as acceleration response, relative loads between the wheel and the road, and passing-through frequency of suspension system were calculated effectively. Content Type Journal Article Pages 1-11 DOI 10.1007/s10010-011-0142-7 Authors Fengrong Bi, School of Mechanical Engineering, Tianjin University, 300072 Tianjin, China S. Jack Hu, Department of Mechanical Engineering, The University of Michigan, Ann Arbor, MI 48109, USA Baoan Song, School of Mechanical Engineering, Hebei University of Technology, 300132 Tianjin, China Journal Forschung im Ingenieurwesen Online ISSN 1434-0860 Print ISSN 0015-7899

Description:    Compressible Mooney–Rivlin theory has been used to model hyperelastic solids, such as rubber and porous polymers, and more recently for the modeling of soft tissues for biomedical tissues, undergoing large elastic deformations. We propose a solution procedure for Lagrangian finite element discretization of a static nonlinear compressible Mooney–Rivlin hyperelastic solid. We consider the case in which the boundary condition is a large prescribed deformation, so that mesh tangling becomes an obstacle for straightforward algorithms. Our solution procedure involves a largely geometric procedure to untangle the mesh: solution of a sequence of linear systems to obtain initial guesses for interior nodal positions for which no element is inverted. After the mesh is untangled, we take Newton iterations to converge to a mechanical equilibrium. The Newton iterations are safeguarded by a line search similar to one used in optimization. Our computational results indicate that the algorithm is up to 70 times faster than a straightforward Newton continuation procedure and is also more robust (i.e., able to tolerate much larger deformations). For a few extremely large deformations, the deformed mesh could only be computed through the use of an expensive Newton continuation method while using a tight convergence tolerance and taking very small steps. Content Type Journal Article Pages 1-13 DOI 10.1007/s00366-011-0225-y Authors Suzanne M. Shontz, Department of Computer Science and Engineering, The Pennsylvania State University, University Park, PA 16802, USA Stephen A. Vavasis, Department of Combinatorics and Optimization, University of Waterloo, Waterloo, ON N2L 3G1, Canada Journal Engineering with Computers Online ISSN 1435-5663 Print ISSN 0177-0667

Description:    Hierarchical ZnO (zinc oxide) nanostructures composed with nano-sheet and micro-flower structures (made from the nano-sheet) have been generated on tinfoil substrate via a chemical bath deposition process. Benefiting from an inherent distinct lattice constant compared with commonly used glass or other kinds of substrate, the tinfoil substrate played an important role on the formation of the hierarchical ZnO nanostructures. The resulting hierarchical ZnO surface shows excellent superhydrophobicity and extremely low water rolling angle after being modified with spin coating Teflon. The flexible and superhydrophobic characteristics of such fabricated substrate will be beneficial for applications requiring bendable and lightweight superhydrophobic substrates. In addition, the multifunctional properties of ZnO nanostructures are expected to broaden the applications to electronic and optical applications. Content Type Journal Article Pages 1-4 DOI 10.1007/s00339-011-6493-y Authors Jun Wu, School of Electronic Science and Engineering, Southeast University, Nanjing, 210096 P.R. China Jun Xia, School of Electronic Science and Engineering, Southeast University, Nanjing, 210096 P.R. China Chen Jing, School of Electronic Science and Engineering, Southeast University, Nanjing, 210096 P.R. China Wei Lei, School of Electronic Science and Engineering, Southeast University, Nanjing, 210096 P.R. China Bao-ping Wang, School of Electronic Science and Engineering, Southeast University, Nanjing, 210096 P.R. China Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    Thin films of silicon carbide (SiC) have been prepared by means of pulsed laser deposition (PLD) on sapphire (Al 2 O 3 ) and Si(100) substrates with a Nd-YAG laser 1064 nm. We achieved the growth of cubic silicon carbide (3C-SiC) films at the temperatures of 650°C from a SiC target in vacuum. The as-deposited films are morphologically and structurally characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD). The use of off-axis PLD method placing the sample at 90° with respect to the target leads to a good quality smooth film. Content Type Journal Article Pages 1-7 DOI 10.1007/s00339-011-6494-x Authors G. Monaco, LUXOR Laboratory, CNR-IFN, Via Trasea 4, Padova, Italy D. Garoli, Physical Department “G. Galilei”, University of Padova, Via Marzolo 8, Padova, Italy M. Natali, CNR-ICIS Corso Stati Uniti 4, Padova, Italy M. G. Pelizzo, LUXOR Laboratory, CNR-IFN, Via Trasea 4, Padova, Italy P. Nicolosi, LUXOR Laboratory, CNR-IFN, Via Trasea 4, Padova, Italy Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    Die Festigkeitshypothesen und Fließflächen aus den klassischen Kursen der Mechanik (die Normalspannungshypothese, die Modelle nach von Mises und Tresca) reichen oft nicht aus, das tatsächliche Verhalten von Bauteilen unter Belastung zu erfassen. Deshalb werden in der Literatur weitere Modelle mit einem oder mehreren Parametern vorgeschlagen. Diese Modelle beschränken allerdings die Geometrien der zulässigen Formen der Flächen im Spannungsraum. In dieser Arbeit wird ein auf die Zugspannung normiertes Druck-Torsion-Diagramm vorgestellt, in dem sich die Modelle inkompressiblen Materialverhaltens miteinander vergleichen lassen. Mit diesem Diagramm wird der Begriff der Symmetrie der Fläche in der π -Ebene verdeutlicht. Die konvexen Flächen inkompressiblen Materialverhaltens sind im Diagramm durch zwei Modelle extremaler Fließfiguren beschränkt. Auf der Basis von verallgemeinerten Modellen (Radcig-Modell und konvexe Kombination der Modelle von Sayir und Haythornthwaite) wird die minimale Anzahl der Parameter für die Abbildung konvexen Formen inkompressiblen Materialverhaltens diskutiert. Wegen der Komplexität werden diese Modelle für die Praxis nicht empfohlen. Daneben wird ein so genanntes geometrisch-mechanisches Modell mit zwei Parametern vorgeschlagen, das mehrere konvexe Formen beinhaltet. Durch die Variation der Potenz der Spannung in diesem Modell wird versucht, einen maximalen Bereich an konvexen Lösungen im Druck-Torsion-Diagramm zu erhalten. Die Analyse von Fließflächen ist mit der Berechnung der Konvexitätsgrenzen verbunden. Bei der analytischen Überprüfung der Konvexität wird von einer Formel von Betten-Troost ausgegangen. Einige Restriktionen, denen die Konvexität unterliegt, werden mit dieser Formel jedoch nicht erkannt. Eine Nachrechnung der Formel von Betten-Troost hat zu zusätzlichen Termen geführt. Da die Einschränkungen bei der Herleitung der Formel nicht bekannt sind, wird hier mit der korrigierten Gleichung gearbeitet. Um kompressibles Materialverhalten beschreiben zu können, wird die erste Spannungsinvariante in die Modellgleichungen eingeführt. In Abhängigkeit von der vorhandenen Potenzen der Vergleichsspannung in den Modellgleichungen werden drei einfache Transformationen vorgeschlagen, die die Anwendung der Modelle deutlich vereinfachen. Bei dieser Vorgehensweise erübrigt sich die Überprüfung der Konvexität in den Meridianschnitten. Content Type Journal Article Pages 1-20 DOI 10.1007/s10010-011-0135-6 Authors A. Bolchoun, Deutsches Kunstoff-Institut Darmstadt, Schloßgartenstr. 6, 64289 Darmstadt, Deutschland V. A. Kolupaev, Deutsches Kunstoff-Institut Darmstadt, Schloßgartenstr. 6, 64289 Darmstadt, Deutschland H. Altenbach, Lehrstuhl Technische Mechanik, Otto-von-Guericke-Universität-Magdeburg, 39106 Magdeburg, Deutschland Journal Forschung im Ingenieurwesen Online ISSN 1434-0860 Print ISSN 0015-7899

Description:    An investigation into a three-dimensional, curved shock wave interacting with a three-dimensional, curved boundary layer on a slender body is presented. Three different nose profiles mounted on a cylindrical body were tested in a supersonic wind tunnel and numerically simulated by solving the Navier–Stokes equations. The conical and hemispherical nose profiles tested were found to generate shock waves of sufficient strength to separate the boundary layer on the cylinder, while the shock wave generated by the ogival profile did not separate the boundary layer. For the separated flow, separation was found to occur predominantly on the windward side of the cylinder with the lee-side remaining shielded from the direct impact of the incident shock wave. A thickening of the boundary layer on the lee-side of all the profiles was observed, and in the conical and hemispherical cases this leads to the re-formation of the incident shock wave some distance away from the surface of the cylinder. A complex reflection pattern off the shock wave/boundary layer interaction (SWBLI) was also identified for the separated flow cases. For comparative purposes, an inviscid simulation was performed using the hemispherical profile. Significant differences between the viscous and inviscid results were noted including the absence of a boundary layer leading to a simplified shock wave reflection pattern forming. The behaviour of the incident shock wave on the lee-side of the cylinder was also affected with the shock wave amalgamating on the surface of the cylinder instead of away from the surface as per the viscous case. Test data from the wind tunnel identified two separation lines present on the cylindrical surface of the hemispherical SWBLI generator. The pair of lines were not explicitly evident in the original CFD simulations run, but were later identified in a high-resolution simulation. Content Type Journal Article Pages 1-16 DOI 10.1007/s00193-011-0322-2 Authors S. Mowatt, Flow Research Unit, School of Mechanical, Industrial and Aeronautical Engineering, University of the Witwatersrand, Private Bag 3, Johannesburg, Wits 2050, South Africa B. Skews, Flow Research Unit, School of Mechanical, Industrial and Aeronautical Engineering, University of the Witwatersrand, Private Bag 3, Johannesburg, Wits 2050, South Africa Journal Shock Waves Online ISSN 1432-2153 Print ISSN 0938-1287

Description:    GaN is a promising material not only for electronic devices but also for photocatalysts. Synthesis of GaN nanocrystal is a key issue to improve performance for these applications. In the present study, GaN nanocrystallites have been synthesized by pulsed laser ablation (PLA), where safe and inactive pure N 2 gases were used as reactive background gases. The third harmonics beam of a Q -switched Nd:YAG laser (355 nm, 10 mJ/pulse, 4 J/(cm 2 pulse)) was used to ablate a sintered high purity GaN target. The deposition substrates were not heated. It was clarified that the formed GaN nanoparticles contained a hexagonal system with the wurtzite structure. The diameter of the nanocrystallites was about 10 nm, and showed only little dependence on the background gas pressure, while the porosity of the assembly of nanocrystallites and content of GaN nanocrystallites in the assembly increased with background gas pressure. Highly porous nanometer-sized GaN film obtained at higher gas pressure is considered to be candidate structures for the photocatalysts. Content Type Journal Article Pages 1-5 DOI 10.1007/s00339-011-6438-5 Authors Takehito Yoshida, Department of Mechanical Engineering, Anan National College of Technology, Anan, Tokushima 774-0017, Japan Soichiro Kakumoto, Department of Physics, Konan University, Kobe, 658-8501 Japan Akira Sugimura, Department of Physics, Konan University, Kobe, 658-8501 Japan Ikurou Umezu, Department of Physics, Konan University, Kobe, 658-8501 Japan Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    Laser Spinning is a new technique that has been shown to quickly produce amorphous inorganic nanofibers from bulk material under atmospheric conditions. This technique employs a high power laser to melt a small volume of the precursor material while a supersonic gas jet provokes its rapid elongation and cooling, producing long micro- and nanofibers within a range of diameters. In this work, the quantity of the fibers produced and the distribution of their diameters are measured and statistically analyzed for different operating conditions. The advance speed of the laser beam over the precursor material is experimentally demonstrated to be the most influencing factor on the diameter of the fibers. Other variables of the process, such as assist gas pressure, were found to have less influence. Content Type Journal Article Pages 1-6 DOI 10.1007/s00339-011-6415-z Authors O. Dieste, Applied Physics Dept., Universidade de Vigo, EEI, Campus as Lagoas, Vigo, Spain F. Quintero, Applied Physics Dept., Universidade de Vigo, EEI, Campus as Lagoas, Vigo, Spain J. Pou, Applied Physics Dept., Universidade de Vigo, EEI, Campus as Lagoas, Vigo, Spain F. Lusquiños, Applied Physics Dept., Universidade de Vigo, EEI, Campus as Lagoas, Vigo, Spain A. Riveiro, Applied Physics Dept., Universidade de Vigo, EEI, Campus as Lagoas, Vigo, Spain Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    The resonant transmission peaks in the asymmetric and symmetric multilayer narrowband transmission filters are theoretically investigated based on the transfer matrix method. In an asymmetric filter there exists only one resonant peak within the photonic band gap, and its position can be changed when the design wavelength is varied. In a symmetric filter, it is found that there are two resonant peaks. Using Bloch wave approximation, an investigation of these two resonant peaks has been made, and they are shown to correspond to the symmetric and antisymmetric field solutions in the defect layer. Content Type Journal Article Pages 1-4 DOI 10.1007/s00339-011-6434-9 Authors Tsung-Wen Chang, Graduate Institute of Electro-Optical Engineering, Chang Gung University, Tao-Yuan, 333 Taiwan Tzong-Jer Yang, Department of Electrical Engineering, Chunghua University, Hsinchu, 300 Taiwan Zheng-Hui Wang, Institute of Electro-Optical Science and Technology, National Taiwan Normal University, Taipei, 116 Taiwan Chien-Jang Wu, Institute of Electro-Optical Science and Technology, National Taiwan Normal University, Taipei, 116 Taiwan Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    Dispersion properties, birefringence and confinement loss between the circular air-hole photonic crystal fiber (CAHPCF) and rotational elliptical air-hole photonic crystal fiber (REAHPCF) are investigated numerically by means of a plane-wave expansion method and a finite element method. Results show that the performances of REAHPCF on flatter dispersion curve, single mode, high birefringence and low confinement loss is better than that of CAHPCF. Content Type Journal Article Pages 1-5 DOI 10.1007/s00339-011-6426-9 Authors Tzong-Jer Yang, Department of Electrical Engineering, Chung Hua University, Hsinchu, 300 Taiwan, ROC Yuan-Fong Chau, Department of Electronic Engineering, Ching Yun University, Jung-Li, 320 Taiwan, ROC Han-Hsuan Yeh, Department of Electronic Engineering, Ching Yun University, Jung-Li, 320 Taiwan, ROC Zheng-Hong Jiang, Department of Electronic Engineering, Ching Yun University, Jung-Li, 320 Taiwan, ROC Yao-Wei Huang, Graduate Institute of Applied Physics, National Taiwan University, Taipei, Taiwan, ROC Kuang-Yu Yang, Graduate Institute of Applied Physics, National Taiwan University, Taipei, Taiwan, ROC Din Ping Tsai, Graduate Institute of Applied Physics, National Taiwan University, Taipei, Taiwan, ROC Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    Most gas dynamic computations in industrial ducts are done in one dimension with cross-section-averaged Euler equations. This poses a fundamental difficulty as soon as geometrical discontinuities are present. The momentum equation contains a non-conservative term involving a surface pressure integral, responsible for momentum loss. Definition of this integral is very difficult from a mathematical standpoint as the flow may contain other discontinuities (shocks, contact discontinuities). From a physical standpoint, geometrical discontinuities induce multidimensional vortices that modify the surface pressure integral. In the present paper, an improved 1D flow model is proposed. An extra energy (or entropy) equation is added to the Euler equations expressing the energy and turbulent pressure stored in the vortices generated by the abrupt area variation. The turbulent energy created by the flow–area change interaction is determined by a specific estimate of the surface pressure integral. Model’s predictions are compared with 2D-averaged results from numerical solution of the Euler equations. Comparison with shock tube experiments is also presented. The new 1D-averaged model improves the conventional cross-section-averaged Euler equations and is able to reproduce the main flow features. Content Type Journal Article Pages 1-16 DOI 10.1007/s00193-011-0321-3 Authors R. Menina, LESEI, Department of Mechanical Engineering, Faculty of Technology, Batna University (UHLB), 1 Avenue Chahid Mohamed El Hadi, 05000 Batna, Algeria R. Saurel, IUSTI, Polytech Marseille, Aix-Marseille University, 5 rue E. Fermi, 13453 Marseille Cedex 13, France M. Zereg, LPEA, Department of Physics, Faculty of Sciences, Batna University (UHLB), 1 Avenue Chahid Mohamed El Hadi, 05000 Batna, Algeria L. Houas, IUSTI, Polytech Marseille, Aix-Marseille University, 5 rue E. Fermi, 13453 Marseille Cedex 13, France Journal Shock Waves Online ISSN 1432-2153 Print ISSN 0938-1287

Description:    UV-absorbing silicon monoxide (SiO x , x ≈1) thin films on fused silica substrates are irradiated by an ArF excimer laser (wavelength 193 nm) in the sub-ablation threshold regime. Multi-pulse irradiation of films with ∼200-nm thickness at a fluence of about 100 mJ/cm 2 leads to a significant increase of the UV transmission, indicating the oxidation of SiO x to SiO 2 . The quality of the obtained films after this laser annealing process depends on the oxygen content of the environment. Irradiation in air at atmospheric pressure leads to the formation of sub-micron-sized oxide particles on top of the film. Structured illumination is applied either to form areas of the film with changed transmission and refractive index, or for the formation of regular particle patterns with sub-micron periods. These processes can be utilized for the fabrication of phase masks or for various types of surface functionalization. Content Type Journal Article Pages 1-6 DOI 10.1007/s00339-011-6451-8 Authors J. Richter, Laser-Laboratorium Göttingen e.V., Hans-Adolf-Krebs-Weg 1, 37077 Göttingen, Germany J. Meinertz, Laser-Laboratorium Göttingen e.V., Hans-Adolf-Krebs-Weg 1, 37077 Göttingen, Germany J. Ihlemann, Laser-Laboratorium Göttingen e.V., Hans-Adolf-Krebs-Weg 1, 37077 Göttingen, Germany Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    Hierarchical ZnO microrods have been prepared by cetyltrimethylammonium bromide (CTAB)-assisted hydrothermal process at low temperature. Sheetlike or fluffy ZnO nanostructures have been developed in a large density on the surface of the microrods. The ZnO cores grow preferentially along [001]; the nanosheets are single crystalline and grow in two dimensions along the [001] and [120] directions. The formation of hierarchical structures has been attributed to the presence of CTAB in the solution, which facilitates the secondary nucleation and growth. The nanosheet-covered hierarchical microrods have been analyzed by Raman and photoluminescence spectroscopy, and they exhibit a blue emission at 465 nm and a strong orange emission at 640 nm. Photocatalytic activities of the products have been examined, and the nanosheet-covered hierarchical microrods display the best activity in photodegradation of phenol due to their unique surface features and high surface area. Content Type Journal Article Pages 1-7 DOI 10.1007/s00339-011-6452-7 Authors Yongqiang Yang, Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua, 321004 China Gaohui Du, Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua, 321004 China Xin Xin, Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua, 321004 China Bingshe Xu, College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan, 030024 China Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    The inverted polymer:fullerene solar cells with structure of ITO/TiO 2 /P3HT:PCBM/MoO 3 /Al have been fabricated, where P3HT and PCBM stand for poly (3-hexylthiophene) and [6,6]-phenyl C 61 -butyric acid methyl ester, respectively. It is discovered that the P3HT:PCBM blend film manipulated into the improved stratification structure, characterized as P3HT crystallite-rich zone close to the top surface and PCBM constituent-rich zone adjacent to the bottom surface, can offer nearly the same power conversion efficiency of solar cell, compared to the one grown into the bulk heterojunction structure, characterized as the bicontinuous interpenetrating network of P3HT and PCBM. We provide an alternative insight to the morphology control of inverted polymer:fullerene solar cells. Content Type Journal Article Pages 1-7 DOI 10.1007/s00339-011-6448-3 Authors Wei Quan, Institute of Polymer Science and Engineering, School of Chemical Engineering, Hebei University of Technology, Tianjin, 300130 People’s Republic of China Cuiran Cheng, Institute of Polymer Science and Engineering, School of Chemical Engineering, Hebei University of Technology, Tianjin, 300130 People’s Republic of China Jinsuo Liu, Institute of Polymer Science and Engineering, School of Chemical Engineering, Hebei University of Technology, Tianjin, 300130 People’s Republic of China Jidong Zhang, State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022 Jilin, People’s Republic of China Donghang Yan, State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022 Jilin, People’s Republic of China Dashan Qin, Institute of Polymer Science and Engineering, School of Chemical Engineering, Hebei University of Technology, Tianjin, 300130 People’s Republic of China Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    Transparent 90GeS 2 ⋅10Ga 2 S 3 (G10) chalcogenide glass-ceramics containing β -GeS 2 nanocrystals was successfully fabricated through controllable crystallization based on the knowledge of its nucleation-rate-like curve. Using the conventional Z-scan method, both large spectral dependence and crystallinity dependence of optical nonlinear parameters were learned under the excitation of different wavelengths that in proximity of the half-bandgap. In particular, a large value of figure of merit (FOM≈11.64) was obtained in the crystallized sample after the heat-treatment at 466°C for 40 h. Although it is not a straightforward process to select an appropriate medium for a specific application, this work opens a new way to construct suitable optical nonlinear properties (e.g., large FOM) though modifying the microstructure of chalcogenide glass-ceramics. Content Type Journal Article Pages 1-6 DOI 10.1007/s00339-011-6454-5 Authors Changgui Lin, College of Materials Science & Chemical Engineering, Ningbo University, Ningbo, 315211 China Laurent Calvez, Laboratoire des Verres et Céramiques, UMR-CNRS 6226, Sciences chimiques de Rennes, Université de Rennes 1, 35042 Rennes Cedex, France Lei Ying, College of Information Science and Engineering, Ningbo University, Ningbo, 315211 China Feifei Chen, College of Information Science and Engineering, Ningbo University, Ningbo, 315211 China Bao’an Song, College of Information Science and Engineering, Ningbo University, Ningbo, 315211 China Xiang Shen, College of Information Science and Engineering, Ningbo University, Ningbo, 315211 China Shixun Dai, College of Information Science and Engineering, Ningbo University, Ningbo, 315211 China Xianghua Zhang, Laboratoire des Verres et Céramiques, UMR-CNRS 6226, Sciences chimiques de Rennes, Université de Rennes 1, 35042 Rennes Cedex, France Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    The combination of high-field physics with nano-plasmonics has proven to be feasible in producing high harmonics of intense laser radiation from noble gases, assisted by the field-enhancement effect in the proximity of metallic nano-antennas. However, the intensity region where harmonics can be generated without irreversible damage to these delicate structures is rather narrow. We explore the damage threshold of gold targets that exhibit regular structures on a nanoscopic scale, either explicitly resonant to the used laser frequency, or off-resonance. These are compared to values for bulk material in order to gain insight into the role of plasmonic resonances in the response of solid targets on intense laser radiation. We find that the presence of such a resonance lowers the threshold fluence (J/cm 2 ) where global structural damage sets in by about an order of magnitude. Statistical deviations either in local pulse energy of the damage inducing laser radiation or in the exact resonance behaviour of singular structures prove to be limited. These results should serve as a guideline for future experiments working near the damage threshold of more sophisticated antenna designs. Content Type Journal Article Pages 1-7 DOI 10.1007/s00339-011-6449-2 Authors C. Kern, Institut für Optik und Quantenelektronik, Physikalisch-Astronomische Fakultät, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena, Germany M. Zürch, Institut für Optik und Quantenelektronik, Physikalisch-Astronomische Fakultät, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena, Germany J. Petschulat, Institut für Angewandte Physik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena, Germany T. Pertsch, Institut für Angewandte Physik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena, Germany B. Kley, Institut für Angewandte Physik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena, Germany T. Käsebier, Institut für Angewandte Physik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena, Germany U. Hübner, Institut für Photonische Technologien, Albert-Einstein-Straße 9, 07745 Jena, Germany C. Spielmann, Institut für Optik und Quantenelektronik, Physikalisch-Astronomische Fakultät, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena, Germany Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    This paper experimentally compares the intensity and phase detection sensitivities of grating coupling surface plasmon resonance (SPR). A simple air-heating method is proposed to implement tiny refractive index changes. An electro-optic heterodyne interferometer is used to obtain both the intensity and phase curves of the grating coupling SPR device. The transient reflectivity and phase curves during the heating process are recorded. The result shows that the phase detection sensitivity is much better than that of the intensity by an order of magnitude. Content Type Journal Article Pages 1-4 DOI 10.1007/s00339-011-6419-8 Authors Wen-Kai Kuo, Department of Electro-Optics Engineering, National Formosa University, 64 Wenhua Rd., Huwei, Yunlin 63208, Taiwan, ROC Chih-Hao Chang, Department of Electro-Optics Engineering, National Formosa University, 64 Wenhua Rd., Huwei, Yunlin 63208, Taiwan, ROC Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    Thin films of fullerenes (C 60 ) were deposited onto silicon using matrix-assisted pulsed laser evaporation (MAPLE). The deposition was carried out from a frozen homogeneous dilute solution of C 60 in anisole (0.67 wt%), and over a broad range of laser fluences, from 0.15 J/cm 2 up to 3.9 J/cm 2 . MAPLE has been applied for deposition of fullerenes for the first time and we have studied the growth of thin films of solid C 60 . The fragmentation of C 60 fullerene molecules induced by ns ablation in vacuum of a frozen anisole target with C 60 was investigated by matrix-assisted laser desorption/ionization (MALDI). Our findings show that intact fullerene films can be produced with laser fluences ranging from 0.15 J/cm 2 up to 1.5 J/cm 2 . Content Type Journal Article Pages 1-6 DOI 10.1007/s00339-011-6432-y Authors S. Canulescu, Department of Photonics Engineering, Risø Campus, Technical University of Denmark, 4000 Roskilde, Denmark J. Schou, Department of Photonics Engineering, Risø Campus, Technical University of Denmark, 4000 Roskilde, Denmark S. F. Nielsen, Materials Research Division, Risø National Laboratory for Sustainable Energy, Technical University of Denmark, 4000 Roskilde, Denmark Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    The recent demonstration of thermal conductivity of rough electrolessly etched Si nanowire (Hochbaum et al., Nature, 451:163, 2008 ) attracted a lot of interest, because it could not be explained by the existing theory; thermal conductivity of rough Si nanowires falls below the boundary scattering of the thermal conductivity. However, nanoscale pores presented in the nanowires (Hochbaum et al., Nano Letters, 9:3550–3554, 2009 ) hinder one to be fully convinced that the surface roughness solely made a contribution to the significant reduction in thermal conductivity. In this study, we synthesized vapor–liquid–solid (VLS) grown rough Si 1− x Ge x nanowire and measured and theoretically simulated thermal conductivity of the nanowire. The thermal conductivity of rough Si 0.96 Ge 0.04 nanowire is an order of magnitude lower than that of bulk Si 0.96 Ge 0.04 and around a factor of four times lower than that of smooth Si 0.96 Ge 0.04 nanowire. This significant reduction could be explained by the fact that the surface roughness scatters medium-wavelength phonons, whereas the long-wavelength phonons are scattered by phonon boundary scattering, and the short-wavelength phonons are scattered by alloy scattering. Content Type Journal Article Pages 1-6 DOI 10.1007/s00339-011-6475-0 Authors Hyoungjoon Kim, School of Mechanical Engineering, Yonsei University, Seoul, 120-749 Korea Yong-Hee Park, Department of Materials Science and Engineering, Yonsei University, Seoul, 120-749 Korea Ilsoo Kim, Department of Materials Science and Engineering, Yonsei University, Seoul, 120-749 Korea Jungwon Kim, School of Mechanical Engineering, Yonsei University, Seoul, 120-749 Korea Heon-Jin Choi, Department of Materials Science and Engineering, Yonsei University, Seoul, 120-749 Korea Woochul Kim, School of Mechanical Engineering, Yonsei University, Seoul, 120-749 Korea Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    In der vorliegenden Arbeit werden die Untersuchungen zur Berechnung der fluidmechanischen Eigenschaften von Kraftstoffdampf-Luft-Gemischen beschrieben. Ziel der Untersuchung war es, Modelle zur Berechnung der dynamischen Viskosität und der Dichte von Kraftstoffdampf-Luft-Gemischen zu erhalten. Dazu wurden Kraftstoffanalysen von Ottokraftstoffen durchgeführt. Aus diesen Daten wurde eine Datenbank mit den Einzelkomponenten aufgebaut. Diese wurde um die temperaturabhängigen Dampfdrücke und dynamische Viskositäten erweitert. In Experimenten konnte der Luftanteil des bei der Betankung aus dem Kraftstoffbehälter entweichenden Gases bestimmt werden. Mit diesen Daten kann von der Zusammensetzung der Flüssigkeit auf die Gasphase und deren Eigenschaften geschlossen werden. Weiter wurden mit den ermittelten Daten parametrische Modelle zur Berechnung der mittleren Molmasse, Dichte und dynamischen Viskosität von Kraftstoffdampf-Luft-Gemischen entwickelt. Content Type Journal Article Pages 1-22 DOI 10.1007/s10010-011-0138-3 Authors Heinz-Jürgen Geurtz, Porsche AG, Porschestrasse, 71287 Weissach, Deutschland Journal Forschung im Ingenieurwesen Online ISSN 1434-0860 Print ISSN 0015-7899

Description:    The impracticality of MHD convection in a porous medium is further clarified. Content Type Journal Article Pages 1-2 DOI 10.1007/s11242-011-9770-5 Authors D. A. Nield, Department of Engineering Science, University of Auckland, Private Bag 92019, Auckland, 1142 New Zealand Journal Transport in Porous Media Online ISSN 1573-1634 Print ISSN 0169-3913

Description:    The number of open source software (OSS) users has increased in recent years. No longer are they limited to technically adept software developers. Many believe that the OSS market share could increase tremendously provided OSS had systems that were easier to use. Although examples of good usable open source software exist, it is agreed that OSS can be made more usable. This study presents an empirical investigation into the impact of some key factors on OSS usability from the end users’ point of view. The research model studies and establishes the relationship between the key usability factors from the users’ perspective and OSS usability. A data set of 102 OSS users from 13 open source projects of various sizes was used to study the research model. The results of this study provide empirical evidence by indicating that the highlighted key factors play a significant role in improving OSS usability. Content Type Journal Article Pages 1-13 DOI 10.1007/s00366-011-0222-1 Authors Arif Raza, Department of Electrical and Computer Engineering, University of Western Ontario, London, ON N6A 5B9, Canada Luiz Fernando Capretz, Department of Electrical and Computer Engineering, University of Western Ontario, London, ON N6A 5B9, Canada Faheem Ahmed, Faculty of Information Technology, United Arab Emirates University, P. O. Box 17551, Al Ain, United Arab Emirates Journal Engineering with Computers Online ISSN 1435-5663 Print ISSN 0177-0667

Description:    An experimental investigation has been carried out to study dual-bell transition behavior in different set ups inside a high-altitude test facility. Cold gas tests were carried out under two different operating conditions namely (i) test nozzle operating in self-evacuation mode and, (ii) test nozzle operating with an additional ejector nozzle (pre-evacuated condition). Although forward transition nozzle pressure ratio does not show any change in its value irrespective of the type of test facility and test set up, the re-transition nozzle pressure ratio shows a significant increase (7–8%) in its value when tested in the high-altitude facility. The latter is caused due to plume blowback effect which dominates during shut down transients in such facilities. Driven by the high atmospheric pressure, the jet exhaust is pushed backwards into the altitude chamber causing the re-transition to occur earlier than that observed in sea-level tests. Further the reduced mass flow rates for nozzle operation in different test set ups in a high-altitude test facility also reduces the magnitude of side-load peaks during the dual-bell transitions. Content Type Journal Article Pages 1-10 DOI 10.1007/s00193-011-0302-6 Authors S. B. Verma, Experimental Aerodynamics Division, CSIR-National Aerospace Laboratories, Bangalore, 560017 India R. Stark, Nozzle Flow Group, DLR Lampoldshausen, Lampoldshausen, Germany C. Génin, Nozzle Flow Group, DLR Lampoldshausen, Lampoldshausen, Germany O. Haidn, Nozzle Flow Group, DLR Lampoldshausen, Lampoldshausen, Germany Journal Shock Waves Online ISSN 1432-2153 Print ISSN 0938-1287

Description:    The effect of rotation on the onset of double diffusive convection in a sparsely packed anisotropic porous layer, which is heated and salted from below, is investigated analytically using the linear and nonlinear theories. The Brinkman model that includes the Coriolis term is employed for the momentum equation. The critical Rayleigh number, wavenumber for stationary and oscillatory modes and a dispersion relation are obtained analytically using linear theory. The effect of anisotropy parameters, Taylor number, Darcy number, solute Rayleigh number, Lewis number, Darcy–Prandtl number, and normalized porosity on the stationary, oscillatory and finite amplitude convection is shown graphically. It is found that contrary to its usual influence on the onset of convection in the absence of rotation, the mechanical anisotropy parameter show contrasting effect on the onset criterion at moderate and high rotation rates. The nonlinear theory based on the truncated representation of Fourier series method is used to find the heat and mass transfers. The effect of various parameters on heat and mass transfer is shown graphically. Some of the convection systems previously reported in the literature is shown to be special cases of the system presented in this study. Content Type Journal Article Pages 1-31 DOI 10.1007/s11242-011-9741-x Authors M. S. Malashetty, Department of Mathematics, Gulbarga University, Jnana Ganga Campus, Gulbarga, 585106 India Irfana Begum, Department of Mathematics, Gulbarga University, Jnana Ganga Campus, Gulbarga, 585106 India Journal Transport in Porous Media Online ISSN 1573-1634 Print ISSN 0169-3913

Description:    Conjugate natural convection-conduction heat transfer in a square porous enclosure with a finite-wall thickness is studied numerically in this article. The bottom wall is heated and the upper wall is cooled while the verticals walls are kept adiabatic. The Darcy model is used in the mathematical formulation for the porous layer and the COMSOL Multiphysics software is applied to solve the dimensionless governing equations. The governing parameters considered are the Rayleigh number (100 ≤ Ra ≤ 1000), the wall to porous thermal conductivity ratio (0.44 ≤ K r ≤ 9.90) and the ratio of wall thickness to its height (0.02 ≤ D ≤ 0.4). The results are presented to show the effect of these parameters on the heat transfer and fluid flow characteristics. It is found that the number of contrarotative cells and the strength circulation of each cell can be controlled by the thickness of the bottom wall, the thermal conductivity ratio and the Rayleigh number. It is also observed that increasing either the Rayleigh number or the thermal conductivity ratio or both, and decreasing the thickness of the bounded wall can increase the average Nusselt number for the porous enclosure. Content Type Journal Article Pages 1-12 DOI 10.1007/s11242-011-9743-8 Authors H. Saleh, School of Mathematical Sciences, Universiti Kebangsaan Malaysia, UKM, Bangi, 43600 Selangor Malaysia N. H. Saeid, Department of Mechanical, Materials and Manufacturing Engineering, The University of Nottingham Malaysia Campus, 43500 Semenyih, Selangor Malaysia I. Hashim, School of Mathematical Sciences, Universiti Kebangsaan Malaysia, UKM, Bangi, 43600 Selangor Malaysia Z. Mustafa, School of Mathematical Sciences, Universiti Kebangsaan Malaysia, UKM, Bangi, 43600 Selangor Malaysia Journal Transport in Porous Media Online ISSN 1573-1634 Print ISSN 0169-3913

Description:    Highly ordered NiO coated Si nanowire arrays are fabricated as electrode materials for electrochemical supercapacitors (ES) via depositing Ni on electroless-etched Si nanowires and subsequently annealing. The electrochemical tests reveal that the constructed electrode has superior electrical conductibility and more active sites per unit area for chemical reaction processes, thereby possessing good cycle stability, high specific capacity, and low internal resistance. The specific capacity is up to 787.5 F g −1 at a discharge current of 2.5 mA and decreases slightly with 4.039% loss after 500 cycles, while the equivalent internal resistance is ∼3.067 Ω. Owing to its favorable electrochemical performance, this ordered hybrid array nanostructure is a promising electrode material in future commercial ES. Content Type Journal Article Pages 1-6 DOI 10.1007/s00339-011-6412-2 Authors Fang Lu, Laboratory for Quantum Engineering and Micro-Nano Energy Technology and Faculty of Materials and Optoelectronic Physics, Xiangtan University, Hunan, 411105 P.R. China Mengchun Qiu, Laboratory for Quantum Engineering and Micro-Nano Energy Technology and Faculty of Materials and Optoelectronic Physics, Xiangtan University, Hunan, 411105 P.R. China Xiang Qi, Laboratory for Quantum Engineering and Micro-Nano Energy Technology and Faculty of Materials and Optoelectronic Physics, Xiangtan University, Hunan, 411105 P.R. China Liwen Yang, Laboratory for Quantum Engineering and Micro-Nano Energy Technology and Faculty of Materials and Optoelectronic Physics, Xiangtan University, Hunan, 411105 P.R. China Jinjie Yin, Laboratory for Quantum Engineering and Micro-Nano Energy Technology and Faculty of Materials and Optoelectronic Physics, Xiangtan University, Hunan, 411105 P.R. China Guolin Hao, Laboratory for Quantum Engineering and Micro-Nano Energy Technology and Faculty of Materials and Optoelectronic Physics, Xiangtan University, Hunan, 411105 P.R. China Xiang Feng, Laboratory for Quantum Engineering and Micro-Nano Energy Technology and Faculty of Materials and Optoelectronic Physics, Xiangtan University, Hunan, 411105 P.R. China Jun Li, Laboratory for Quantum Engineering and Micro-Nano Energy Technology and Faculty of Materials and Optoelectronic Physics, Xiangtan University, Hunan, 411105 P.R. China Jianxin Zhong, Faculty of Materials and Optoelectronic Physics, Xiangtan University, Hunan, 411105 P.R. China Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    In this paper we report a simple method that enables the easy fabrication of ordered ZnO nanowire arrays using Anodic Aluminium Oxide (AAO) template. We have used a vacuum injection technique to fill solution into the pores of an AAO template. The AAO template has been fabricated by a two-step anodization process using 0.3 M oxalic acid (H 2 C 2 O 4 ) solution under a constant voltage of 40 V. The AAO template formed through this process has been detached from Al substrate via an anodic voltage pulse using perchloric acid (HClO 4 ) solution (70%). The nanowires of ZnO have been synthesized by injecting the saturated Zn(NO 3 ) 2 solution into the pores of the detached AAO template using a vacuum pump. The ZnO nanowires synthesized by this technique have been found dense & continuous with uniform diameter throughout the length of the wire. The structural characteristics of AAO template and ZnO nanowires have been studied by Field Emission Scanning Electron Microscope (FESEM), Atomic force microscope (AFM) and Transmission Electron Microscope (TEM). Content Type Journal Article Pages 1-6 DOI 10.1007/s00339-011-6402-4 Authors Nagesh Kumar, Department of Physics and Centre of Nanotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667 India G. D. Varma, Department of Physics and Centre of Nanotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667 India R. Nath, Department of Physics and Centre of Nanotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667 India A. K. Srivastava, Indus Synchrotrons Utilization Division, Raja Ramanna Centre for Advanced Technology, Indore, 452013 India Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    The electrical characteristics of thin TiO 2 films prepared by metal–organic chemical vapor deposition grown on a p-type InP substrate were studied. For a TiO 2 film of 4.7 nm on InP without and with ammonium sulfide treatment, the leakage currents are 8.8×10 −2 and 1.1×10 −4  A/cm 2 at +2 V bias and 1.6×10 −1 and 8.3×10 −4  A/cm 2 at −2 V bias. The lower leakage currents of TiO 2 with ammonium sulfide treatment arise from the improvement of interface quality. The dielectric constant and effective oxide charge number density are 33 and 2.5×10 13  cm 2 , respectively. The lowest mid-gap interface state density is around 7.6×10 11  cm −2  eV −1 . The equivalent oxide thickness is 0.52 nm. The breakdown electric field increases with decreasing thickness in the range of 2.5 to 7.6 nm and reaches 9.3 MV/cm at 2.5 nm. Content Type Journal Article Pages 1-6 DOI 10.1007/s00339-011-6404-2 Authors Ming-Kwei Lee, Department of Electrical Engineering, National Sun Yat-sen University, Kaohsiung, 80424 Taiwan, R.O.C. Chih-Feng Yen, Department of Electrical Engineering, National Sun Yat-sen University, Kaohsiung, 80424 Taiwan, R.O.C. Shih-Chen Chiu, Department of Electrical Engineering, National Sun Yat-sen University, Kaohsiung, 80424 Taiwan, R.O.C. Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    Electrical transport properties on polycrystalline Cu(In,Ga)Se 2 (CIGS) (Ga/(In+Ga) ≈35%) thin films were examined by conductive atomic force microscopy. The CIGS thin films with a (112) preferential or random texture were deposited on Mo-coated glass substrates. Triangular pyramidal grain growths were observed in the CIGS thin films preferentially textured to the (112) planes. Current maps of the CIGS surface were acquired with a zero or non-zero external voltage bias. The contrast of the images on the grain boundaries and intragrains displayed the conduction path in the materials. Local current–voltage measurements were performed to evaluate the charge conduction properties of the CIGS thin films. Content Type Journal Article Pages 1-6 DOI 10.1007/s00339-011-6408-y Authors R. H. Shin, Department of Physics, Ewha Womans University, Seoul, 120-750 Korea W. Jo, Department of Physics, Ewha Womans University, Seoul, 120-750 Korea D.-W. Kim, Department of Physics, Ewha Womans University, Seoul, 120-750 Korea Jae Ho Yun, Korea Institute of Energy Research, Daejeon, 305-343 Korea S. Ahn, Korea Institute of Energy Research, Daejeon, 305-343 Korea Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    We consider a four-layer waveguide structure as an optical waveguide sensor. One of the layers is a metamaterial with negative permittivity and permeability. We show that the sensitivity of the proposed optical waveguide sensor can be dramatically enhanced by using a metamaterial layer between the guiding and the cladding layers. The variation of the sensitivity of the proposed waveguide sensor with different parameters of the waveguide is studied. Content Type Journal Article Pages 1-4 DOI 10.1007/s00339-011-6406-0 Authors Sofyan A. Taya, Physics Department, Islamic University, P.O. Box 108, Gaza Strip, Gaza, Palestine Mohammed M. Shabat, Physics Department, Islamic University, P.O. Box 108, Gaza Strip, Gaza, Palestine Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396

Description:    Following studies of biological attachment systems, the principle of contact splitting, according to which splitting up the contact into finer subcontacts increases adhesion, was introduced. However, numerous attempts at employing this principle in producing dry adhesives were unsuccessful, prompting us to test its validity. Here, we show that in addition to the increase in number of subcontacts, the contact splitting model also implies a built-in increase in contact area. Thus, based on this model, it is impossible to say which parameter leads to increase in adhesion, the increasing number of subcontacts, as accepted to think, or just an increase in contact area, which is a trivial result. To clarify this point, we show experimentally what happens if we keep the contact area constant, while increasing the number of subcontacts in the “equal load sharing” mode, which was never done before. In contrast to the contact splitting principle, our measurements clearly demonstrate that, in flat-punch-patterned conformal contact, the pull-off force remains the same even when the number of subcontacts increases by two orders of magnitude. Our finding suggests that the contact splitting idea can only work in thin-film-based contacts, which are indeed employed in most biological temporary attachment systems. Content Type Journal Article Pages 1-6 DOI 10.1007/s00339-011-6394-0 Authors Michael Varenberg, Department of Mechanical Engineering, Technion-IIT, Haifa, 32000 Israel Boris Murarash, Department of Mechanical Engineering, Technion-IIT, Haifa, 32000 Israel Yuri Kligerman, Department of Mechanical Engineering, Technion-IIT, Haifa, 32000 Israel Stanislav N. Gorb, Department of Functional Morphology and Biomechanics, Zoological Institute of the University of Kiel, Kiel, 24098 Germany Journal Applied Physics A: Materials Science & Processing Online ISSN 1432-0630 Print ISSN 0947-8396