Duck Young Chung, Ctirad Uher, Mercouri G. Kanatzidis
AbstractSolid solutions CsBi4‐xSbxTe6 (x ≤ 2.0) and CsBi4Te6‐ySey (y ≤ 3.0) are synthesized by direct reaction of stoichiometric mixtures of Cs and the precursors Bi2‐aSbaTe3 (a = 0.1—0.5), and Bi2Te3‐bSeb (b = 0.1—1.5), resp.
AbstractDie isotypen Verbindungen Cs3Sb5X9 (X = S, Se) wurden durch methanolothermale Reaktion von Cs2CO3 mit Sb2X3 bei einer Temperatur von 180°C dargestellt. Die Phasen enthalten Polychalkogenoantimonit‐anionen [Sb5X93−]∞, in denen die Grundelemente ecken‐ sowie kantenverknüpfte ψ‐SbX3 Tetraeder bzw. ψ‐SbX5 Oktaeder sind. Diese Anionen bilden spiegel‐symmetrische Doppelschichten senkrecht zur b‐Achse. Während eins der beiden unabhängigen Cs‐Kationen etwas oberhalb bzw. unterhalb der Außenfläche einer Schicht liegt und auch von einer benachbarten Schicht koordiniert wird, befindet sich das zweite Cs‐Kation innerhalb der Doppelschicht.
ABSTRACTThe compound types A1+xM3-2xBi7+xSe14, A1−xM3−xBi11+xSe20, A1−xM4−xBi11+xSe21 and A1−xM5−xBi11+xSe22 (A = K, Rb, Cs; M = Sn, Pb) form from reactions involving A2Se, Bi2Se3, M and Se. The single crystal structures reveal that they are all structurally related so that they all belong to the homologous series Am[M6Se8]m[M5+nSe9+n] (M = di- and trivalent metal), whose characteristics are three-dimensional anionic frameworks with tunnels filled with alkali ions. The building units that make up these structures are derived from different sections of the NaCl lattice. In these structures, the Bi and Sn (Pb) atoms are extensively disordered over the metal sites of the chalcogenide network, giving rise to very low thermal conductivity. These phases are all narrow gap semiconductors with 0.25 < Eg< 0.60 eV and many possess physico-chemical and charge transport properties suitable for thermoelectric investigations.
Jun‐Ho Kim, Duck‐Young Chung, Mercouri G. Kanatzidis
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Department of CSE, GMRIT, Rajam, India., Kotagiri Srividya, A. Mary Sowjanya, Sowjanya
et al.
Social media content on the internet is increasing day by day. Since media knowledge helps people in making decisions, web based businesses give their clients an opportunity to express their opinions about items available on the web in the form of surveys and reviews. Sentiment analysis can be used on product reviews or tweets, comments, blogs to infer individual’s feelings or attitudes. Here Aspect Based Sentiment Analysis is used to extract most interesting aspect of a particular product from unlabeled text. We have developed two models for aspect/feature extraction.Model1 uses POS tagging whereas Model2 utilizes TFIDF .In Model 1 we start with noun phrase algorithm and extend it to adjectives and adverbs to extract all the aspect terms. In model2 after data preprocessing TDIDF technique is used. The relative importances of the aspects are calculated and the most important positive, negative and neutral aspects are presented to the user. Naïve Bayes, Support Vector machine, Decision Tree, KNN were used to classify the sentiment polarity of the generated aspects.
A. L. M. Zanelatto, E. M. S. Ribeiro, R. d. J. Napolitano
We present triplet and singlet scattering lengths for X–Cs133 collisions (X=Li6,7, Na23, K39,40,41, and Rb85,87). We consider the short-range potential-energy curves based on high-quality ab initio calculations and the long-range potential described by accurate dispersion coefficients available in the literature. Using a Fermi function to smoothly connect the short- and long-range terms we construct the potential for all R and evaluate the scattering length for each mixed species X–Cs. In particular, we predict that the cross section for inelastic processes between Na23 and Cs133 and between K40 and Cs133 will be small as compared with the respective elastic cross sections.