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Hyperfine interactions, magnetic, transport and structural properties of La0.67Ca0.33Mn0.9457Fe0.06O3

Physica Status Solidi (C) Current Topics in Solid State physics 2006年第1期3卷 138-142页

作者： Przewoźnik, J. Zukrowski, J. Chmist, J. Tarnawski, Z. Kolodziejczyk, A. Krop, K. Kellner, K. Gritzner, G. Department of Solid State Physics Faculty of Physics and Applied Computer Science AGH University of Science and Technology Al. Mickiewicza 30 30-059 Cracow Poland Department of Physics Rzeszów University of Technology Al. Powstańców Warszawy 6 35-959 Rzeszów Poland Institute for Chemical Technology of Inorganic Materials Johannes Kepler University Linz 4040 Linz Austria

The La0.67Ca0.33Mn0.9457Fe0.06O3 compound was studied using powder X-ray diffraction, VSM magnetometry, four-probe resistance measurements and 57Fe Mössbauer spectroscopy. The Mössbauer measurements were performed between 15 K and 850 K and showed good agreement between Curie temperature determined from temperature dependences of the hyperfine field (141 K) and DC magnetization (142 K). They show the inhomogeneous character of the magnetic transition and the coexistence of ferromagnetic and paramagnetic phases in the temperature range 110 K ≤ T 3+ for Mn3+ strongly affects the magnetic and transport properties of the parent compound. It causes a difference between Curie temperature and the metal-insulator transition temperature of about 80 K and a strong reduction of their values. X-ray diffraction measurements were performed between 4 and 500 K and showed complete suppression of the thermal expansion anomaly at Curie temperature. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

关键词： Curie temperature

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Effect of Densification on the Density of Vibrational States of Glasses

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Physical Review Letters 2006年第13期97卷 135501-135501页

作者： A. Monaco A. I. Chumakov G. Monaco W. A. Crichton A. Meyer L. Comez D. Fioretto J. Korecki R. Rüffer European Synchrotron Radiation Facility BP 220 F-38043 Grenoble France Physik Department E13 Technische Universität München D-85747 Garching Germany INFM CRS-SOFT c/o Universitá di Roma “la Sapienza” I-00185 Roma Italy Dipartimento di Fisica Universitá di Perugia I-06123 Perugia Italy Faculty of Physics and Applied Computer Science AGH University of Science and Technology Kraków Poland

We studied the effect of densification on the vibrational dynamics of a Na2FeSi3O8 glass. The density of vibrational states (DOS) has been measured using nuclear inelastic scattering. The corresponding changes in the microscopic, intermediate-range, and macroscopic properties have also been investigated. The results reveal that, in the absence of local structure transformations, the Debye level and the glass-specific excess of vibrational states above it have the same dependence on density, and the evolution of the DOS is fully described by the transformation of the elastic medium.

关键词： Glass

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Mathematical Simulation of Nonlinear Effects in Micro Ring Resonator

Mathematical Simulation of Nonlinear Effects in Micro Ring R...

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IEEE International Nanoelectronics Conference (INEC)

作者： P.P. Yupapin Chat Teeka P. Chitsakul Fiber Optics Research Laboratory Department of Applied PhysicsFaculty of Science King Mongkut''s Institute of Technology Ladkrabang Bangkok Thailand Scientific Equipment Center Faculty of Science and Technology Suan Dusit Rajabhat University Bangkok Thailand Nonlinear Science Research Group Department of Mathematics and Computer ScienceFaculty of Science King Mongkut''s Institute of Technology Ladkrabang Bangkok Thailand

In this paper, we demonstrate the mathematical simulation data of light traveling in an optical micro ring resonator. The optical nonlinear properties such as chaos, bifurcation, bistability and instability of the optical outputs are studied. By changing the optical parameters that result the change of the optical output intensities, the nonlinear behaviors such as bifurcation, chaos and bistability effects are occurred. The relationship between the optical parameters and output intensities are derived by varying the interested parameters such as coupling coefficient (κ), nonlinear refractive index (n 2 ), and linear phase shift (φ 0 ). The results obtained are presented and plotted showing that the optical parameters can be changed i. e. controlled, and then the nonlinear effects characteristics can be predicted and controlled.

关键词： Optical ring resonators Optical bistability Fiber nonlinear optics Optical refraction Optical variables control Optical feedback Optical signal processing Nonlinear optics Chaos Optical fibers

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Data mining approaches to explaining aerosol formation

Data mining approaches to explaining aerosol formation

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3rd Biennial Meeting of the International Environmental Modelling and Software Society: Summit on Environmental Modelling and Software, iEMSs 2006

作者： Hyvönen, S. Junninen, H. Laakso, L. Dal Maso, M. Grönholm, T. Bonn, B. Keronen, P. Aalto, P. Hiltunen, V. Pohja, T. Launiainen, S. Tunved, P. Hansson, H.C. Hari, P. Mannila, H. Kulmala, M. Helsinki Institute for Information Technology Department of Computer Science University of Helsinki P.O.Box 68 FI-00014 Helsinki Finland Department of Physics University of Helsinki P.O. Box 64 FI-00014 Helsinki Finland Hyytiälä Forestry Field Station University of Helsinki Helsinki Finland Department of Applied Environmental Science Stockholm University Sweden Department of Forest Ecology Faculty of Agriculture and Forestry University of Helsinki Helsinki Finland

ISBN: (纸本)1424308526

Atmospheric aerosol particle formation is frequently observed in various environments. Yet, despite numerous studies, processes behind these so called nucleation events remain unclear. In this work we describe the use of data mining techniques to detect factors influencing particle formation. These techniques are applied to a dataset of eight years of 80 variables collected at the boreal forest station (SMEAR II) in Southern Finland, including air pollutant, weather, gas and particle measurements. In a previous study classification methods have been used together with feature selection in order to understand what causes nucleation. Each day was classified as an event day, when a nucleation event occurs, or as a nonevent day, and looking at which features were selected gives us information on which factors are important for the aerosol formation process. This way it was possible to identify two key variables, relative humidity and preexisting aerosol particle surface (condensation sink), capable of explaining 88% of the nucleation events. Using these two variables a nucleation probability function could be derived. In this paper this nucleation probability function has been tested on data collected from other sites, Värriö in Northern Lapland and Aspvreten in Sweden. We show that in the extreme conditions in Värriö the nucleation parameter does not work, whereas in Aspvreten the two key variables can be used to identify nucleation events, though the nucleation parameter has to be adjusted slightly. The two key variables are related to mechanisms that prevent nucleation. One reason for the domination of preventive mechanisms could be the existence of more than one mechanism causing nucleation. Another intriguing phenomenon, possibly related to this, is the temporal variation of nucleation events. We have investigated temporal phenomena in nucleation by using classification methods in a sliding *** discuss some aspects of this approach and present some results ob

关键词： Atmospheric aerosols

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Ramsauer-Townsend effect in muonic atom scattering

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Physical Review A 2006年第3期73卷 034501-034501页

作者： F. Mulhauser A. Adamczak G. A. Beer V. M. Bystritsky M. Filipowicz M. C. Fujiwara T. M. Huber O. Huot R. Jacot-Guillarmod P. Kammel S. K. Kim P. E. Knowles A. R. Kunselman G. M. Marshall A. Olin C. Petitjean T. A. Porcelli L. A. Schaller V. A. Stolupin J. Woźniak J. Zmeskal Department of Physics University of Fribourg CH-1700 Fribourg Switzerland Henryk Niewodniczański Institute of Nuclear Physics Polish Academy of Sciences PL-31342 Cracow Poland Department of Physics and Astronomy University of Victoria Victoria Canada V8W 2Y2 Laboratory of Nuclear Problems Joint Institute for Nuclear Research Dubna 141980 Russia Faculty of Fuels and Energy AGH University of Science and Technology PL-30059 Krakow Poland TRIUMF Vancouver Canada V6T 2A3 Gustavus Adolphus College St. Peter Minnesota 56082 USA University of California Berkeley California 94720 USA Physics Department Jeonbuk National University Jeonju Jeonbuk 561-756 S. Korea University of Wyoming Physics Laramie Wyoming 82071-3905 USA Paul Scherrer Institute CH-5232 Villigen PSI Switzerland Faculty of Physics and Applied Computer Science AGH University of Science and Technology PL-30059 Krakow Poland Stefan Meyer Institut für Subatomare Physik Austrian Academy of Sciences A-1090 Wien Austria

We present the final results of an experimental study of μd and μt atom scattering in solid hydrogen cooled to 3K. Strong effects resulting from the Ramsauer-Townsend effect have been observed in the TRIUMF experiment E742 where muons were stopped in thin frozen layers of hydrogen. The measured Ramsauer-Townsend minimum energy for both μd and μt atoms and the minimum cross section are in agreement with theory.

关键词： SOLID HYDROGEN MOLECULAR FORMATION CATALYZED FUSION MU DEUTERIUM

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A fully computational model for predicting percutaneous drug absorption

A fully computational model for predicting percutaneous drug...

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作者： Neumann, Dirk Kohlbacher, Oliver Merkwirth, Christian Lengauer, Thomas Center for Bioinformatics Saar Bldg. 36.1 Saarland University 66123 Saarbrücken Germany Wilhelm Schickard Institute for Computer Science University of Tübingen Sand 14 72076 Tübingen Germany Department of Information Technologies Faculty of Physics Astronomy and Applied Informatics Jagiellonian University Reymonta 4 PL 30-059 Kraków Poland Max-Planck-Institut für Informatik Stuhlsatzenhausweg 85 66123 Saarbrücken Germany

The prediction of transdermal absorption for arbitrary penetrant structures has several important applications in the pharmaceutical industry. We propose a new data-driven, predictive model for skin permeability coefficients k p based on an ensemble model using k-nearest-neighbor models and ridge regression. The model was trained and validated with a newly assembled data set containing experimental data and structures for 110 compounds. On the basis of three purely computational descriptors (molecular weight, calculated octanol/water partition coefficient, and solvation free energy), we have developed a model allowing for the reliable, purely computational prediction of skin permeability coefficients. The model is both accurate and robust, as we showed in an extensive validation (correlation coefficient for leave-one-out cross validation: Q = 0.948, mean standard error: 0.2 for log kp). © 2006 American Chemical Society.

关键词： Drug products

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Symmetry analysis of quadrupolar and structural ordering in single-q phases of UPd3

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Journal of physics: Conference Series 2006年第1期30卷

作者： W Sikora F Bialas L Pytlik J Malinowski Faculty of Physics and Applied Computer Science AGH University of Science and Technology al.Mickiewicza 30 30-059 Krakow Poland Nowy Sacz School of Business - National Louis University Nowy Sacz Poland

The paper describes the application of symmetry analysis to construction of possible quadrupolar ordering modes in a crystal with a given space group symmetry. The matrix representing a given tensor property (e.g. quadrupolar moment) is converted to a vector form, for which the standard symmetry analysis algorithms can be applied. The possible ordering modes are obtained as linear combinations of basis vectors of irreducible representations of a given space group, but taking into account the constraints, specific for a given physical quantity (e.g. symmetric matrix form and zero trace for quadrupolar tensors). The results are applied to the single-q phases of UPd3 compound. For completeness the possible structural ordering modes are also calculated, which are consistent with the symmetry of a given quadrupolar ordering.

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X-ray detectors for existing and future synchrotron radiation sources

X-ray detectors for existing and future synchrotron radiatio...

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Photonics Applications in Industry and Research IV

作者： DĄbrowski, W. Faculty of Physics and Applied Computer Science AGH University of Science and Technology Krakow

The research potential offered by synchrotron radiation sources is largely limited by lack of adequate detectors. This is to some extent true for existing synchrotron radiation sources while for third generation synchrotron radiation sources being developed this is a primary problem. New research areas in life, physical and material sciences demand new detectors suitable for time resolved high resolution imaging and with spectroscopic properties. This paper presents an overview of trends and recent acluevements in advanced detector technologies developed over last decade for high energy perticle physics experiments. The detector requirements for instrumentation of synchrotron radiation experiments are discussed. The basic technologies of high-resolution position sensitive detectors, silicon strip detectors and hybrid pixel detectors are reviewed. Fundamental limitations and perspectives of these detector technologies are discussed.

关键词： Photodetectors

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Quality assurance system for the endcap module hybrids of the ATLAS semiconductor tracker

Quality assurance system for the endcap module hybrids of th...

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11th Workshop on Electronics for LHC and Future Experiments, LECC 2005

作者： Dwuznik, M. AGH University of Science and Technology Faculty of Physics and Applied Computer Science Al. Mickiewicza 30 30-059 Kraków Poland

ISBN: (纸本)9290832622

The quality assurance system for semi-industrial production scale of multichip hybrid circuits is presented. The hybrids are parts of the silicon strip detector modules of the Semiconductor Tracker (SCT) of the forthcoming ATLAS detector. The edcap hybrid houses the readout and data transmission ASICs, providing the full functionality needed for binary readout of double-sided silicon strip detector modules. The hybrids are assembled in the industry using pretested components. The full quality assurance testing, including visual inspection, electrical testing and burn-in tests, is performed in the institutes of the SCT collaboration. The testing procedures and test results are presented.

关键词： Quality assurance

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Low noise multichannel circuits for physics and biology applications

Low noise multichannel circuits for physics and biology appl...

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Photonics Applications in Industry and Research IV

作者： Gryboś, Pawel Faculty of Physics and Applied Computer Science AGH University of Science and Technology al. Mickiewicza 30 30-059 Kraków Poland

Experimental techniques in physics, material science, biology and medicine want to gain profit from the advantages of the VLSI technology by using a new generation of electronic measurement systems based on parallel signal processing from the multielement sensors. In most cases key problems for building such system are multichannel mixed-mode Application Specific Integrated Circuits, which are capable to process small amplitude signals from multielement sensor. In this class of integrated circuits several important problems like power limitation, low level of noise, good matching performance and crosstalk effects must be solved simultaneously. This presentation shows two ASICs which, given the original solutions implemented and their universal properties, can be used in different applications and are significant milestones in experimental techniques. The first presented ASIC is the 64-channel charge amplifier with binary readout architecture for a low energy X-ray imaging techniques. This integrated circuit connected to silicon strip detector can be used in powder diffractometry and then it reduces the measurement time by two order of magnitude. The second presented ASIC is multichannel low noise readout for extracellular neural recording, which is able to cope with extracellular neuronal recording for the systems comprising several hundreds of electrodes. Important steps forward in this design are a novel solution for band-pass filters for low frequency range, which follow requirements for good matching, low power and small silicon area. This ASIC can be used to monitor the neural activity of such complicated system like retina or brain.

关键词： Circuit theory

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