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作者： Gondek, L. Arulray, A. Baran, S. Nenkov, K. Penc, B. Szytula, A. Tomala, K. Faculty of Physics and Applied Computer Science AGH University of Science and Technology Mickiewicza 30 30-059 Kraków Poland BENSC Hahn-Meitner-Institute Glienicker Street 100 14 109 Berlin-Wannsee Germany M Smoluchowski Institute of Physics Jagiellonian University Reymonta 4 30-059 Kraków Poland Leibnitz-Institute for Solid State and Materials Research PO Box 270116 D-01 171 Dresden Germany International Laboratory of High Magnetic Fields and Low Temperatures Gajowicka 95 53-529 Wroclaw Poland

X-ray and neutron diffraction, isothermal magnetization, magnetic susceptibility and specific heat measurements were performed on polycrystalline samples of Ho3-xYxCu4Sn4 for x = 0, 1, 2. All samples crystallize with the orthorhombic structure of Gd 3Cu4Ge4 type. Within this crystal structure the rare earth atoms occupy two non-equivalent 2d and 4e positions. The presented x-ray data clearly indicate that introduced yttrium atoms prefer the 4e sublattice. Increase of the yttrium content causes a decrease of the Néel temperature from 7.6 K for x = 0 down to about 1.5 K for x = 2. Neutron diffraction data indicate that only Ho magnetic moments within the 2d sublattice order antiferromagnetically. The Ho moments are parallel to the b-axis. They form a collinear magnetic structure with the propagation vector k = (0,1/2,0) with [++ ] sign sequence. © 2008 IOP Publishing Ltd.

关键词： Rare earths

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Design of the MsAa‐4 Mössbauer Spectrometer

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AIP Conference Proceedings 2008年第1期1070卷 162-169页

作者： A. Błachowski K. Ruebenbauer J. Żukrowski R. Górnicki aMössbauer Spectroscopy Division Institute of Physics Pedagogical University PL‐30‐084 Kraków ul. Podchorążych 2 Poland bSolid State Physics Department Faculty of Physics and Applied Computer Science AGH University of Science and Technology PL‐30‐059 Kraków Al. Mickiewicza 21 Poland cRENON PL‐30‐732 Kraków ul. Gliniana 15/15 Poland

An entirely new Mössbauer spectrometer MsAa‐4 is currently being under design and construction. New features as compared to the basic features of the previous generation MsAa‐3 spectrometer could be summarized as follows. Completely digital processing of the γ‐ray detector signal beyond the Gaussian shape filter/amplifier is to be implemented. The spectrometer is going to be able to accommodate external multiple detector heads. Up to 128 γ‐ray spectra in 16384 channels of 32‐bit each and up to 512 Mössbauer spectra in 4096 channels of 32‐bit each could be collected simultaneously, provided the proper external multiple detector head is used. The count‐rate per single detector is limited to about 105 counts per second in total. Improved precision of the reference function from 12‐bit to 16‐bit is to be provided. The reference function is stored in 8192 channels per a complete cycle. Addition of the random noise to the reference corner prism of the Michelson‐Morley calibration interferometer is to be introduced to avoid spurious fringes due to the phase lock‐up. An integrated universal temperature controller being able to use a variety of the temperature sensors is to be interconnected properly with the spectrometer. The spectrometer is now a stand‐alone network device as it is equipped with the Ethernet connection to the outside world. Fast and high precision digital oscilloscope is to be incorporated to the spectrometer as the intrinsic unit. This oscilloscope could monitor signals at various crucial points of the internal spectrometer electronics. Modular design and use of the strict standards allows easy reconfiguration for other applications than Mössbauer spectroscopy.

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High pressure structural phase transitions in Sr from ab initio calculations

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Physical Review B 2008年第17期77卷 174118-174118页

作者： A. Phusittrakool T. Bovornratanaraks R. Ahuja U. Pinsook Large-Scale Simulation Research Laboratory National Electronics and Computer Technology Center Pathumthani 12120 Thailand Department of Physics Faculty of Science Chulalongkorn University Bangkok 10330 Thailand Condensed Matter Theory Group Department of Physics Uppsala University Box 530 SE-751 21 Uppsala Sweden Applied Materials Physics Department of Materials and Engineering Royal Institute of Technology (KTH) S-100 44 Stockholm Sweden

The pressure-induced phase transition in strontium, including the recent experimental observation of high-pressure phase Sr-IV, was investigated theoretically using the projector augmented wave method. We also concentrated on the experimentally observed β-tin structure as this structure has never been found in any other alkaline-earth metals. The fcc-bcc phase transition was reproduced, but Sr-IV was found to be energetically more stable than the β-tin structure at all pressures. By considering enthalpy, the sequence of the phase transitions along the pressure range is fcc→bcc→Sr-IV. With some detailed examination, we concluded that the β-tin structure is either a metastable state or a coexisting phase, and further experimental investigation is suggested.

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MSGCROC - an ASIC for high count rate readout of position sensitive Microstrip Gas Chambers for thermal neutrons

MSGCROC - an ASIC for high count rate readout of position se...

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IEEE Symposium on Nuclear science (NSS/MIC)

作者： Andrea S. Brogna Siro Buzzetti Wladyslaw Dabrowski Tomasz Fiutowski Burckhard Gebauer Bartosz Mindur Christian J. Schmidt Christian Schulz Hans K. Soltveit Robert Szczygiel Ulrich Trunk Piotr Wiacek Physikalisches Institut der Universität Heidelberg Heidelberg Germany INFM and Politecnico di Milano Milan Italy Faculty of Physics and Applied Computer Science of Science and Technology AGH University of Science and Technology Krakow Poland Helmholtz-Zentrum Berlin für Materialien und Energie GmbH Germany Deutsches Electronen Synchrotron DESY Hamburg Germany

In this paper we report on the development of an ASIC for readout of position sensitive neutron detectors based on low-pressure Micro-Strip Gas Chambers with solid composite 157 Gd/CsI converter. Global counting rates of 10 8 cps for a detector area of 25×25 cm 2 covered with 400×400 strips requiring 2 ns time resolution for coincidences of signals from X- and Y-strips set very demanding requirements for the ASIC performance.

关键词： Application specific integrated circuits Microstrip Neutrons Spatial resolution Position sensitive particle detectors Signal resolution X-ray detection X-ray detectors Silicon Strips

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Approaching the thermodynamic limit in equilibrated scale-free networks

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Physical Review E 2008年第6期78卷 061125-061125页

作者： B. Waclaw L. Bogacz W. Janke Institut für Theoretische Physik Universität Leipzig Postfach 100920 04009 Leipzig Germany Department of Information Technologies Faculty of Physics Astronomy and Applied Computer Science Jagellonian University Reymonta 4 30-059 Kraków Poland Centre for Theoretical Sciences (NTZ) Universität Leipzig Emil-Fuchs-Straβe 1 04105 Leipzig Germany

We discuss how various models of scale-free complex networks approach their limiting properties when the size N of the network grows. We focus mainly on equilibrated networks and their finite-size degree distributions. Our results show that the position of the cutoff in the degree distribution, kcutoff, scales with N in a different way than predicted for N→∞; that is, subleading corrections to the scaling kcutoff∼Nα are strong even for networks of order N∼109 nodes. We observe also a logarithmic correction to the scaling for degenerated graphs with the degree distribution π(k)∼k−3. On the other hand, the distribution of the maximal degree kmax may have a different scaling than the cutoff and, moreover, it approaches the thermodynamic limit much faster. We argue that kmax∼Nα′ with an exponent α′=min[α,1∕(γ−1)], where γ is the exponent in the power law π(k)∼k−γ. We also present some results on the cutoff function and the distribution of the maximal degree in equilibrated networks.

关键词： Complex networks

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Differential iron distribution in seeds of two closely related legume species

Differential iron distribution in seeds of two closely relat...

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XIV International Symposium on Iron Nutrition and Interactions in Plants Annual Meeting of HarvestPlus—China 2008(第十四届植物铁营养与相互作用国际研讨会)

作者： D.Urbanski S.Husted C.Cvitanich N.Sandal E.Or(l)owska J.Stougaard E.(O).Jensen W.J.Przyby(l)owicz J.Mesjasz-Przyby(l)owicz M.A.Klein M.A.Grusak Institute of Molecular Biology University of Aarhus Denmark Department of Agricultural Sciences Faculty of Life Sciences University of Copenhagen Denmark Themba LABS Somerset West South Africa Faculty of Physics and Applied Computer Science AGH University of Science and Technology CracowPoland Themba LABS Somerset West South Africa Department of Pediatrics Baylor College of Medicine.USDA-ARS Children''s Nutrition Research CenterHouston TX USA

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Magnetism of ultra-thin iron films seen by the nuclear resonant scattering of synchrotron radiation

Magnetism of ultra-thin iron films seen by the nuclear reson...

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作者： Slezak, T. Stankov, S. Zajac, M. Slezák, M. Matlak, K. Spiridis, N. Laenens, B. Planckaert, N. Rennhofer, M. Freindl, K. Wilgocka-Slezak, D. Rüffer, R. Korecki, J. Faculty of Physics and Applied Computer Science AGH University of Science and Technology al. Mickiewicza 30 30-059 Cracow Poland Institute of Catalysis and Surface Chemistry Polish Academy of Sciences ul. Niezapominajek 8 30-239 Cracow Poland European Synchrotron Radiation Facility BP220 F-38043 Grenoble France Instituut voor Kern- en Stralingsfysica K.U.Leuven Celestijnenlaan 200D B-3001 Leuven Belgium Fakultät für Physik Universität Wien Strudlhofgasse 4 A-1090 Wien Austria

Conversion electron Mössbauer spectroscopy proved in the past to be very useful in studying surface and ultrathin film magnetism with, monolayer resolution. Twenty years later, its time-domain analogue, the nuclear resonant scattering (NRS) of synchrotron radiation, showed up to be by orders of magnitude faster and more efficient. The most important features of NRS based on simulations and experimental data have been discussed. It has been shown how the isotopic sensitivity of NRS, combined with the 57Fe probe layer concept, was explored to study influence of the interlayer exchange coupling to FeAu monoatomic superlattices on the magnetic properties of the iron monolayer on Au(001). In the second example, combination of UHV conditions and the high brilliance of the third generation synchrotron source is used to probe the evolution of spin structure in epitaxial Fe films on W(110) via the accumulation of high quality time spectra directly during the 57Fe film growth.

关键词： Synchrotron radiation

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Readout electronics for LumiCal detector

Readout electronics for LumiCal detector

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2007 International Linear Collider Workshop, LCWS 2007 and International Linear Collider Meeting, ILC 2007

作者： Idzik, Marek Swientek, Krzysztof Kulis, Szymon AGH University of Science and Technology Faculty of Physics and Applied Computer Science Cracow Poland

The readout electronics for the luminosity detector (LumiCal) at ILC is discussed. First, the challenges of LumiCal and the proposed solutions are described together with the overall readout architecture chosen. Then a more detailed description of the front-end and the analog to digital convertion blocks follows. In particular the design and simulation results of the prototype preamplifier, shaper and basic ADC blocks are presented.

关键词： Analog to digital conversion

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Pattern Formation in Thin Polymer Films Containing Conducting Polyaniline

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Macromolecular Symposia 2008年第1期263卷

作者： Jakub Haberko Joanna Raczkowska Andrzej Bernasik Wojciech Łużny Jakub Rysz Andrzej Budkowski Faculty of Physics and Applied Computer Science AGH-University of Science and Technology al. Mickiewicza 30 30-059 Kraków Poland M. Smoluchowski Institute of Physics Jagiellonian University ul. Reymonta 4 30-059 Kraków Poland

Summary: In the present work knowledge the authors tried to direct the phase separation process in a thin polymer composite film to manufacture a polymer pattern via self organisation of the blend components. The Au substrate was modified by applying with a PDMS stamp a pattern of alternating stripes of a self-assembled monolayer. This in turn influenced the microstructure of the blend, allowing for the production of elongated domains repeating the pattern of the substrate. The blends studied in this work contained conducting polyaniline doped with camphorsulfonic acid or diphenyl phosphate and polystyrene. The role of the dopant was to induce electrical conductivity in polyaniline as well as to improve its solubility in common organic solvents. The microstructure of thin films was analysed using atomic force microscopy (AFM), dynamic secondary ion mass spectroscopy (dSIMS) and optical microscopy.

关键词： conjugated polymers polyaniline polymer blends self-organisation thin films

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Structure and magnetic properties of nanoparticles trapped in a carbon matrix along with the catalytic growth of carbon nanotubes

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Materials science and Engineering C 2007年第5-8 SPEC. ISS.期27卷 1167-1170页

作者： Morozan, Adina Figiel, H. Zukrowski, J. Japa, Ewa Tokarz, W. Dumitru, Anca Stamatin, Ioan 3 Nano-SAE Research Centre University of Bucharest MG-38 077125 Bucharest-Magurele Romania Department of Solid State Physics Faculty of Physics and Applied Computer Science AGH-University of Science and Technology 30-059 Krakow Poland

The combination of magnetic materials and carbon nanotubes (CNTs) is a promising research direction with a wide range of applications such as magnetic storage and drug delivery free of toxicity. It is well known that some transition metals are mandatory for the nucleation and growth of CNTs by pyrolysis. This paper deals with a new approach where Fe-C nanostructures are developed in a carbon matrix with a random network of CNTs by the polymers pyrolysis (phenol-formaldehyde resins and polyvinyl alcohol) and ferrocene up to 900 °C in inert atmosphere. The proposed method is simple and could be a promising way to produce magnetic nanoparticles coated with carbon as well as CNTs. The characterization (TEM, Mössbauer spectroscopy) and magnetic properties of the carbon-iron system are systematically investigated. © 2006 Elsevier B.V. All rights reserved.

关键词： Nanoparticles

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