Applied Physics A (APPL PHYS A-MATER)

Publications in this journal

• Article: Characterization of bronze Roman coins of the fifth century called nummi through different analytical techniques

  C. Canovaro, I. Calliari, M. Asolati, F. Grazzi, A. Scherillo
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  ABSTRACT: Metallographic techniques, Energy-dispersive X-ray fluorescence (EDXRF), Scanning electron microscopy (SEM) in backscattered-electron mode (BSE) with energy-dispersive microanalysis (EDS) and Time-of-Flight Neutron Diffraction (ToF-ND) have been used to investigate the composition and the microstructure of some 5th century A.D. Roman coins, called nummi. The analysis confirms that the coins were produced by casting Cu-Sn-Pb alloys followed by a weak mechanical working. The presence of surface phenomena, more or less severe depending on the samples, has limited the usefulness of the EDXRF analysis for what concerns the determination of bulk properties. The results of ToF-ND and EDS analysis on cross section are in good agreement and, in addition, through ToF-ND it was possible to derive the phase composition in a non destructive way. The results of analysis show that the flans were obtained for solidification in the mold, then hammered to the desired thickness and finally coined. The content of Sn, higher of 5% identifies a western production, in contrast with what happens in the eastern mints.
  Applied Physics A 05/2013;
• Article: A leaky-wave antenna using double-layered metamaterial transmission line

  He-Xiu Xu, Guang-Ming Wang, Mei-Qing Qi
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  ABSTRACT: A novel leaky-wave antenna (LWA) is proposed using a double-layered resonant-type metamaterial (MTM) transmission line (TL). The MTM TL is composed of periodically arranged complementary split ring resonators (CSRRs), capacitive gaps, and metal caps. By introducing the extra metal cap in additional layer of the basic artificial MTM TL element, an increased left handed capacitor by 36 % with respect to that using none cap is engineered, which is necessary to implement a balanced condition, and thus a continuous beam steering property of the resultant LWA in terms of providing phase constants from negative to positive values. For verification, a 20-cells LWA sample is fabricated and measured. Consistent numerical and experimental results have both validated the continuous frequency-scanning capabilities of the antenna from backward −29° to forward 72° (including the broadside). The proposed prescription opens a way toward new types of MTM LWAs with easily engineered broadside radiation.
  Applied Physics A 04/2013; 111(2):549-555.
• Article: Porosity-moderated ultrafast electron transport in Au nanowire networks

  Evaggelos Magoulakis, Athanassia Kostopoulou, Gerorgios N. Arvanitakis, Antonios G. Kanaras, Antonis N. Andriotis, Alexandros Lappas, Panagiotis A. Loukakos
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  ABSTRACT: We demonstrate for first time the ultrafast properties of a newly formed porous Au nanostructure. The properties of the porous nanostructure are compared with those of a solid gold film using time-resolved optical spectroscopy. The experiments suggest that under the same excitation conditions the relaxation dynamics are slower in the former. Our observations are evaluated by simulations based on a phenomenological rate equation model. The impeded dynamics has been attributed to the porous nature of the structure in the networks, which results in reduced efficiency during the dissipation of the laser-deposited energy. Importantly, the porosity of the complex three-dimensional nanostructure is introduced as a geometrical control parameter of its ultrafast electron transport.
  Applied Physics A 04/2013;
• Article: Efficiency of applying ammonium oxalate for protection of monumental limestone by poultice, immersion and brushing methods

  D. Mudronja
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  ABSTRACT: Samples of cretaceous limestone have been treated with three application methods (poultice, immersion and brushing) using different concentrations of ammonium oxalate solution (AmOx) and varying treatment time in order to test the efficiency of surface and in-depth formation of a protective layer of calcium oxalate (CaOx). Synchrotron-based microanalytical techniques (SR-μXRD with 12.5 μm×7.5 μm (H×V) probe size, SR-μFTIR with 10 μm×10 μm and 8 μm×20 μm probe sizes) and laboratory μFTIR, XRD and SEM have been employed for analysis of the treated samples. Synchrotron-based techniques showed variations in the CaOx distribution along the surface on a micrometer scale. All treatments resulted in the development of a CaOx layer with a maximum thickness of approximately 40 μm. Application by the brushing method with 10 1-min applications with 5-min breaks during one hour showed a development of the calcium oxalate layer equivalent to the poultice treatment taking 10 h. This treatment could be preferred for large marble or limestone surfaces where poultice usage is economically not feasible.
  Applied Physics A 04/2013; 111(1):109-119.
• Article: Near-field modification of femtosecond pulse to enhance single shot filamentation

  Farid Ahmed, Md. Shamim Ahsan, Martin B. G. Jun, and Man Seop Lee
  Applied Physics A 03/2013;
• Article: Investigations on crystalline and optical perfection of SHG oriented KDP crystals

  S.Dinakaran, S.Verma, S.J.Das, G.Bhagavannarayan, S.Kar, K.S.Bartwal
  Applied Physics A 02/2013; Vol. 99,:445-450.
• Article: New markers to identify the provenance of lapis lazuli: trace elements in pyrite by means of micro-PIXE

  A. Re, D. Angelici, A. Lo Giudice, E. Maupas, L. Giuntini, S. Calusi, N. Gelli, M. Massi, A. Borghi, L.M. Gallo, G. Pratesi, P.A. Mandò
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  ABSTRACT: Lapis lazuli has been used for glyptics and carving since the fifth millennium BC to produce jewels, amulets, seals, inlays, etc; the identification of the origin of the stone used for carving artworks may be valuable for reconstructing old trade routes. Since ancient lapis lazuli art objects are precious, only non-destructive techniques can be used to identify their provenance, and ion beam analysis (IBA) techniques allow us to characterise this stone in a fully non-invasive way. In addition, by using an ion microprobe, we have been able to focus the analysis on single crystals, as their typical dimensions may range from a few microns to hundreds of microns. Provenance markers, identified in previous IBA studies and already presented elsewhere, were based on the presence/absence of mineral phases, on the presence/quantity of trace elements inside a phase and on characteristic features of the luminescence spectra. In this work, a systematic study on pyrite crystals, a common accessory mineral in lapis lazuli, was carried out, following a multi-technique approach: optical microscopy and SEM-EDX to select crystals for successive trace element micro-PIXE measurements at two Italian facilities, the INFN Laboratori Nazionali di Legnaro and the INFN LABEC laboratory in Firenze. The results of this work allowed us to obtain new markers for lapis lazuli provenance identification.
  Applied Physics A 02/2013; 111(1):69-74.
• Article: Quantum efficiency of technical metal photocathodes under laser irradiation of various wavelengths

  F. Le Pimpec, C. J. Milne, F. Ardana-Lamas, C.P. Hauri
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  ABSTRACT: Quantum efficiency studies for various laser wavelengths and various technical metal surfaces were carried out in a dedicated unbaked vacuum chamber in the absence of a significant electrical field. Copper, magnesium, aluminum, and aluminum–lithium photocathodes were irradiated by two different high power, high repetition rate, laser systems. We have observed an emission of electrons for photon energies below the work function of the material. This is explained by multiple photon absorption by the photocathode. We have not observed any degradation of the QE for these materials, but an improvement when irradiating them over a long period of time. This is contrary to observations made in RF photoguns.
  Applied Physics A 02/2013;
• Article: Effect of Substrate Temperature on the Properties of Nanocrystalline Zirconia Thin Films Prepared by Pulsed Laser Deposition

  G. Balakrishnan, K. Thanigaiarul, P. Sudhakara and Jung Il Song
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  ABSTRACT: The zirconium oxide (ZrO2) thin films are deposited on Si (100) and quartz substrates at various substrate temperatures (room temperature–973 K) at an optimized oxygen partial pressure of 3 × 10−2 mbar using pulsed laser deposition technique. The effect of substrate temperature on microstructural, optical and mechanical properties of the films is investigated. The X-ray diffraction studies show that the films deposited at temperatures ≤773 K are monoclinic, while the films deposited at temperatures ≥873 K show both monoclinic and tetragonal phases. Tetragonal phase content increases with the increase of substrate temperatures. The surface morphology and roughness are investigated using atomic force microscope in contact mode. The optical properties of the films show that the refractive indices (at 550 nm) are found to increase from 1.84 to 2.35 as the temperature raises from room temperature (RT) to 973 K. Nanoindentation measurements show that the hardness of the films is 11.8 and 13.7 GPa for the films deposited at 300 and 973 K, respectively.
  Applied Physics A 02/2013; 110(2):427.
• Article: Efficient second harmonic conversion efficiency through one-dimensional coupled resonator poled nonlinear optical waveguide

  S. M. Hamidi, T. Parvini, M. M. Tehranchi
  Applied Physics A 01/2013;
• Article: An ultrathin transparent metamaterial polarization transformer based on a twist-split-ring resonator

  Yongzhi Cheng, Yan Nie, XianWang, Rongzhou Gong
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  ABSTRACT: In this paper, an ultrathin transparent metamate- rial polarization transformer using a circular twist-split-ring resonator (TSRR) was proposed and investigated experi- mentally and numerically. The experimental and simulated results exhibit an asymmetric transmission only for forward and backward propagating linearly polarized waves. An in- cident linearly polarized wave can convert its polarization nearly completely to the cross direction after transmission under certain conditions. The simulated spatial evolution of the electric field further indicates that the twist structure functions as a perfect polarization transformer at certain fre- quencies.
  Applied Physics A 01/2013;