Atomic Dynamics in Complex Metallic Alloys

2013 ◽  
Vol 1517 ◽  
Author(s):  
Holger Euchner ◽  
Stephane Pailhès ◽  
Tsunetomo Yamada ◽  
Ryuji Tamura ◽  
Tsutomu Ishimasa ◽  
...  
Keyword(s):  
Lattice Dynamics ◽  
Structural Complexity ◽  
Building Blocks ◽  
Metallic Alloys ◽  
Strong Reduction ◽  
Large Numbers ◽  
Unit Cells ◽  
Dynamics Simulations ◽  
The Impact ◽  
Complex Metallic Alloys

ABSTRACTComplex Metallic Alloys (CMAs) are metallic solids of high structural complexity, consisting of large numbers of atoms in their unit cells. Consequences of this structural complexity are manifold and give rise to a variety of exciting physical properties. The impact that such structural complexity may have on the lattice dynamics will be discussed. The surprising dynamical flexibility of Tsai-type clusters with the symmetry breaking central tetrahedron will be addressed for Zn6Sc, while in the Ba-Ge-Ni clathrate system the dynamics of encaged Ba guest atoms in the surrounding Ge-Ni host framework is analysed with respect to the experimentally evidenced strong reduction of lattice thermal conductivity. For both systems experimental results from neutron scattering are analyzed and interpreted on atomistic scale by means of ab initio and molecular dynamics simulations, resulting in a picture with the respective structural building blocks as the origin of the peculiarities in the dynamics.

scholarly journals Lattice dynamics and macroscopic properties in complex metallic alloys

2014 ◽  
Vol 70 (a1) ◽  
pp. C399-C399
Author(s):  
Pierre-François Lory ◽  
Marc de Boissieu ◽  
Peter Gille ◽  
Mark Johnson ◽  
Marek Mihalkovic ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Lattice Dynamics ◽  
Disordered Systems ◽  
Inelastic Neutron Scattering ◽  
Building Blocks ◽  
Metallic Alloys ◽  
Experimental Investigations ◽  
Icosahedral Symmetry ◽  
Macroscopic Properties ◽  
Complex Metallic Alloys

Complex metallic alloys are long-range ordered materials, characterized by large unit cells, comprising several tens to thousands of atoms [1]. These complex alloys often consist of characteristic, cluster building blocks, which in many cases show icosahedral symmetry. Numerous complex phases are known, that can be described in a rather simple way as the periodic or quasi-periodic packing of such atomic clusters. The lattice dynamics of CMAs has been the subject of both theoretical and experimental investigations in view of their interesting macroscopic properties such as low thermal conductivity. In aperiodic crystals in the higher wave-vector regime, theory predicts that the lattice modes are critical: they are neither extended as in simple crystals nor localized as in disordered systems [2]. Experimentally phonons have been studied in different CMAs systems like clathrates, approximant-crystals and quasicrystals. For all of them, acoustic modes are well-defined for wave-vectors close to Brillouin zone centres, but then broaden rapidly as the result of coupling with other excitations [3]. We will present a combined experimental and atomistic simulation study of the lattice dynamics of the complex metallic alloy Al13Co4 phase [4], which is a periodic approximant of the decagonal phase. Particular attention will be paid to the differences between the periodic and `quasiperiodic' directions. Inelastic neutron scattering measurements carried out on a large, single grain on a triple-axis spectrometer will be compared to simulations, focussing on the dispersion relations and the intensity distribution of the S(Q,ω) scattering function, which is a very sensitive test of the model [3]. Simulations are performed with DFT methods and empirical, oscillating, pair potentials [5]. In addition, thermal conductivity calculations, based on the Green-Kubo method, will be compared with measurements, which show a weak anisotropy [6-7]. In this way, the structure-dynamics-properties relation for CMAs is thoroughly explored.

scholarly journals Lattice dynamics of the complex metallic alloys o-Al13Co4

2017 ◽  
Vol 73 (a2) ◽  
pp. C1314-C1314
Author(s):  
Marc De Boissieu ◽  
Pierre François Lory ◽  
Marek Mihalkovic ◽  
Valentina Giordanno ◽  
Peter Gille ◽  
...  
Keyword(s):  
Lattice Dynamics ◽  
Metallic Alloys ◽  
Complex Metallic Alloys

Those Properties of CMAs We Know Something About

2008 ◽  
Vol 138 ◽  
pp. 407-450 ◽  
Author(s):  
V. Fournée ◽  
Marie Geneviève Barthés-Labrousse ◽  
Jean Marie Dubois
Keyword(s):  
Surface Properties ◽  
Structural Complexity ◽  
Complex Compounds ◽  
Metallic Alloys ◽  
Unit Cell ◽  
Crystallographic Structure ◽  
Ultimate State ◽  
Metallic Character ◽  
New Compounds ◽  
Complex Metallic Alloys

New tools are nowadays available to solve the crystallographic structure of complex compounds in metallic alloy systems and a vivid interest manifests itself to discover new compounds in multi-constituent alloys with hundreds or more atoms per unit cell. Meanwhile, it is observed that the metallic character of the alloy progressively disappears with increasing the number of atoms in the unit cell. This contribution focuses at a few examples of this atypical behavior of complex metallic alloys, including quasicrystals as the ultimate state of structural complexity in a crystal made of metals. Emphasis is put on surface properties.

Syrian Crisis and Migration

2015 ◽  
Vol 12 (3) ◽  
pp. 181-192 ◽  
Author(s):  
Pinar Yazgan ◽  
Deniz Eroglu Utku ◽  
Ibrahim Sirkeci
Keyword(s):  
Human Mobility ◽  
Special Issue ◽  
Host Countries ◽  
Syrian Crisis ◽  
Mass Migration ◽  
Large Numbers ◽  
And Migration ◽  
Europe Today ◽  
The Impact ◽  
Near Future

With the growing insurrections in Syria in 2011, an exodus in large numbers have emerged. The turmoil and violence have caused mass migration to destinations both within the region and beyond. The current "refugee crisis" has escalated sharply and its impact is widening from neighbouring countries toward Europe. Today, the Syrian crisis is the major cause for an increase in displacement and the resultant dire humanitarian situation in the region. Since the conflict shows no signs of abating in the near future, there is a constant increase in the number of Syrians fleeing their homes. However, questions on the future impact of the Syrian crisis on the scope and scale of this human mobility are still to be answered. As the impact of the Syrian crisis on host countries increases, so does the demand for the analyses of the needs for development and protection in these countries. In this special issue, we aim to bring together a number of studies examining and discussing human mobility in relation to the Syrian crisis.

Mechanically-Tunable Quantum Interference in Ferrocene-Based Single-Molecule Junctions

2020 ◽  
Author(s):  
María Camarasa-Gómez ◽  
Daniel Hernangómez-Pérez ◽  
Michael S. Inkpen ◽  
Giacomo Lovat ◽  
E-Dean Fung ◽  
...  
Keyword(s):  
Single Molecule ◽  
Quantum Interference ◽  
Degrees Of Freedom ◽  
Building Blocks ◽  
Ferrocene Derivative ◽  
Single Molecule Junctions ◽  
Molecule Junction ◽  
Single Molecule Junction ◽  
The Impact ◽  
D Orbitals

Ferrocenes are ubiquitous organometallic building blocks that comprise a Fe atom sandwiched between two cyclopentadienyl (Cp) rings that rotate freely at room temperature. Of widespread interest in fundamental studies and real-world applications, they have also attracted<br>some interest as functional elements of molecular-scale devices. Here we investigate the impact of<br>the configurational degrees of freedom of a ferrocene derivative on its single-molecule junction<br>conductance. Measurements indicate that the conductance of the ferrocene derivative, which is<br>suppressed by two orders of magnitude as compared to a fully conjugated analog, can be modulated<br>by altering the junction configuration. Ab initio transport calculations show that the low conductance is a consequence of destructive quantum interference effects that arise from the hybridization of metal-based d-orbitals and the ligand-based π-system. By rotating the Cp rings, the hybridization, and thus the quantum interference, can be mechanically controlled, resulting in a conductance modulation that is seen experimentally.<br>

Model Pembelajaran Teams Games Tournaments (TGT) untuk Meningkatkan Hasil Belajar Siswa

2019 ◽  
Vol 3 (2) ◽  
pp. 110
Author(s):  
Suwarno Suwarno
Keyword(s):  
Social Capital ◽  
Academic Success ◽  
Service Learning ◽  
Learning Outcomes ◽  
School Effectiveness ◽  
Social Trust ◽  
Building Blocks ◽  
Learning Model ◽  
Committee Report ◽  
The Impact

<p><strong>A</strong><strong>bstract</strong><strong>. </strong>This study aims to determine the effectiveness of the Teams Games Tournament (TGT) learning model to improve student learning outcomes. This research is important because the lecture learning model makes learning meaningless so it impacts on low learning outcomes. This research uses quasi experiment using control class and experimental class. Respondents in this study were students of class X SMK 8 Semarang Academic Year 2017/2018. Sample selection using random sampling, class X1 is <em>used</em> as a control class and X2 is an experimental class. The experimental class was given an intervention by learning Teams Games Tournaments (TGT), while the control class used lecture learning. The effectiveness of the model was measured by the student test analysis method. then analyzed by completeness test and average difference test. The findings of this study are the learning outcomes of experimental class students achieving better learning outcomes than classes using the lecture method.</p><p><strong><em>Keywords</em></strong><em>: Learning Model, Teams Games Tournaments (TGT)</em><em>. Students</em></p><p><strong><br /></strong></p><p><strong>Daftar Pustaka</strong></p><p align="center"> </p><p>Bofota, Y. B., &amp; Bofota, Y. B. (2017). <em>The impact of social capital on children educational outcomes : the case of Tanzania The impact of social capital on children educational outcomes : The case of Tanzania</em>.</p><p>Cahuc, P., Shleifer, A., &amp; Algan, Y. (2014). <em>Teaching Practices and Social Capital</em>. (6052).</p><p>Catts, R., &amp; Ozga, J. (2015). <em>What is Social Capital and how might it be used in Scotland ’ s Schools ?</em> (36).</p><p>Flint, N. (2017). <em>Full report Schools , communities and social capital : building blocks in the ’ Big Society ’ Contents</em>.</p><p>Goddard, R. D. (2016). <em>Relational Networks , Social Trust , and Norms : A Social Capital Perspective on Students ’ Chances of Academic Success</em>. <em>25</em>(1), 59–74.</p><p>Eddy Prasongko, 2017. Team Game Tournament. Bandung. Jawa Barat</p><p>Endang Poerwanti, dkk. 2008. <em>Asesmen Pembelajaran SD.</em> Jakarta: Direktorat Jendral Pendidikan Tinggi Departemen Pendidikan Nasional</p><p>Hargreaves, A. (2015). <em>School Social Capital and School Effectiveness</em>. <em>37</em>, 119–136.</p><p>Kurnia, Inggridwati. dkk. 2018. <em>Perkembangan belajar peserta didik</em><em>.</em> Jakarta: Direktorat Jendral Pendidikan Tinggi Departemen Pendidikan Nasional</p><p>Purwanto. M Ngalim. 2015. <em>Psikologi Pendidikan</em>. Bandung: PT Remaja Rosdakarya</p><p>Siddiq, M. Djauhar. 2018. <em>Pengembangan Bahan Pembelajaran SD</em>. Jakarta: Direktorat Jendral Pendidikan Tinggi Departemen Pendidikan Nasional.</p><p>Sugiyono, 2005. Metode Penelitian Kuantitatif, Kualitatif dan Rn D, Bandung Aftabeta</p><p>Lash, D., &amp; Belfiore, G. (2017). <em>5 Essentials in Building Social Capital Report 4 of the MyWays Student Success Series</em>. (October).</p><p>Mikiewicz, P., Jonasson, J. T., Gudmundsson, G., Blondal, K. S., &amp; Korczewska, D. M. (2011). <em>Comparative research between Poland and Iceland</em>.</p><p>Schlesselman, L., Borrego, M., Bloom, T. J., Mehta, B., Drobitch, R. K., &amp; Smith, T. (2015). An Assessment Of Service-Learning In 34 US Schools Of Pharmacy Follow Up On The 2001 Professional Affairs Committee Report. <em>American Journal of Pharmaceutical Education</em>, <em>79</em>(8). https://doi.org/10.5688/ajpe798116</p><p><em><br /></em></p>

Language, procedures, and the non-perceptual origin of natural number concepts

2016 ◽  
Author(s):  
David Barner
Keyword(s):  
General Framework ◽  
Ad Hoc ◽  
Building Blocks ◽  
Number Words ◽  
Linguistic Markers ◽  
Logical Foundations ◽  
Large Numbers ◽  
Perceptual Representations ◽  
Positive Integers ◽  
Perceptual Systems

Perceptual representations – e.g., of objects or approximate magnitudes –are often invoked as building blocks that children combine with linguisticsymbols when they acquire the positive integers. Systems of numericalperception are either assumed to contain the logical foundations ofarithmetic innately, or to supply the basis for their induction. Here Ipropose an alternative to this general framework, and argue that theintegers are not learned from perceptual systems, but instead arise toexplain perception as part of language acquisition. Drawing oncross-linguistic data and developmental data, I show that small numbers(1-4) and large numbers (~5+) arise both historically and in individualchildren via entirely distinct mechanisms, constituting independentlearning problems, neither of which begins with perceptual building blocks.Specifically, I propose that children begin by learning small numbers(i.e., *one, two, three*) using the same logical resources that supportother linguistic markers of number (e.g., singular, plural). Several yearslater, children discover the logic of counting by inferring the logicalrelations between larger number words from their roles in blind countingprocedures, and only incidentally associate number words with perception ofapproximate magnitudes, in an *ad hoc* and highly malleable fashion.Counting provides a form of explanation for perception but is not causallyderived from perceptual systems.

Development of Strategies for Glycopeptide Synthesis: An Overview on the Glycosidic Linkage

2020 ◽  
Vol 24 (21) ◽  
pp. 2475-2497
Author(s):  
Andrea Verónica Rodríguez-Mayor ◽  
German Jesid Peralta-Camacho ◽  
Karen Johanna Cárdenas-Martínez ◽  
Javier Eduardo García-Castañeda
Keyword(s):  
Chemical Synthesis ◽  
Solid Phase ◽  
Building Blocks ◽  
Heterogeneous Environments ◽  
Phase Synthesis ◽  
Low Concentrations ◽  
Biological Sources ◽  
Synthetic Routes ◽  
The Impact ◽  
Potential Use

Glycoproteins and glycopeptides are an interesting focus of research, because of their potential use as therapeutic agents, since they are related to carbohydrate-carbohydrate, carbohydrate-protein, and carbohydrate-lipid interactions, which are commonly involved in biological processes. It has been established that natural glycoconjugates could be an important source of templates for the design and development of molecules with therapeutic applications. However, isolating large quantities of glycoconjugates from biological sources with the required purity is extremely complex, because these molecules are found in heterogeneous environments and in very low concentrations. As an alternative to solving this problem, the chemical synthesis of glycoconjugates has been developed. In this context, several methods for the synthesis of glycopeptides in solution and/or solid-phase have been reported. In most of these methods, glycosylated amino acid derivatives are used as building blocks for both solution and solid-phase synthesis. The synthetic viability of glycoconjugates is a critical parameter for allowing their use as drugs to mitigate the impact of microbial resistance and/or cancer. However, the chemical synthesis of glycoconjugates is a challenge, because these molecules possess multiple reaction sites and have a very specific stereochemistry. Therefore, it is necessary to design and implement synthetic routes, which may involve various protection schemes but can be stereoselective, environmentally friendly, and high-yielding. This review focuses on glycopeptide synthesis by recapitulating the progress made over the last 15 years.

Complex Metallic Alloys for Applications in Magnetic Refrigeration

2015 ◽  
Vol 8 (2) ◽  
pp. 129-154
Author(s):  
Benjamin Podmiljsak ◽  
Paul J. McGuiness ◽  
Spomenka Kobe
Keyword(s):  
Magnetic Refrigeration ◽  
Metallic Alloys ◽  
Complex Metallic Alloys
Sign in / Sign up

Export Citation Format

Share Document