177,254 research outputs found
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Bonding analyses of unconventional carbon allotropes
No full textUtilizing first-principles electronic-structure calculations, we present the chemical-bonding analyses of hypothetical carbon allotropes based on tetrahedral structure motifs such as T-carbon, TY-carbon and T-graphene. While previous publications on these novel allotropes have dealt with ab initio phonon, band structure and DOS calculations, the focus of this work is the partitioning of the band-structure energy in terms of bonding, nonbonding and antibonding contributions. We re-evaluate the chance of making such allotropes by careful bond analyses and compare them to already known equivalents, namely diamond, graphene and the Buckminsterfullerene molecule. A synthetic route is proposed to a new compound, called TY-carbodiimide, that exhibits similar structure and bonding properties as TY-carbon
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
A chemical link between Ge-Sb-Te and In-Sb-Te phase-change materials
No full textWe identify a similar feature in the chemical-bonding nature of seemingly different phase-change materials (PCMs) for data storage. This affords new insight into the "next-generation'' material In3SbTe2, establishes a hitherto missing link to the more ubiquitous Ge-Sb-Te alloys, and encourages the search for new PCMs beyond established electron-counting schemes
Density-functional theory guided advances in phase-change materials and memories
No full textPhase-change materials (PCMs) are promising candidates for novel data-storage and memory applications. They encode digital information by exploiting the optical and electronic contrast between amorphous and crystalline states. Rapid and reversible switching between the two states can be induced by voltage or laser pulses. Here, we review how density-functional theory (DFT) is advancing our understanding of PCMs. We describe key DFT insights into structural, electronic, and bonding properties of PCMs and into technologically relevant processes such as fast crystallization and relaxation of the amorphous state. We also comment on the leading role played by predictive DFT simulations in new potential applications of PCMs, including topological properties, switching between different topological states, and magnetic properties of doped PCMs. Such DFT-based approaches are also projected to be powerful in guiding advances in other materials-science fields
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Transition-metal carbodiimides
No full textTransition-metal carbodiimides, with the general formula Mx(NCN)y, are gaining renewed interest due to their excellent electrochemical and photocatalytic properties.[1-2] These quasi-binary compounds can be seen as nitrogen-containing versions of MxOy oxides generated by the isovalent replacement of O2− by the extended carbodiimide −N=C=N− or cyanamide N≡C−N2− dianions. Indeed, their crystal structures show similarities to oxides, with a clear propensity for close-packed anionic arrangements. However, the lower electronegativity of NCN compared to O, along with a greater degree of charge delocalization, results in phases with enhanced covalent character and reduced band gaps.A natural development, therefore, is to expand the range of transition-metal carbodiimides to include ternary and higher-order compounds, which may lead to new or improved properties. In this talk, I will discuss the synthesis of the first non-binary transition-metal carbodiimides, analyse their crystal structures, with the support of DFT calculations, and investigate their diverse physicochemical properties and potential applications. [3-5]References[1] M. T. Sougrati, A. Darwiche, X. Liu, A. Mahmoud, R. P. Hermann, S. Jouen, L. Monconduit, R. Dronskowski,* L. Stievano,* Angew. Chem. Int. Ed., 2016, 55, 5090[2] A. J. Corkett, O. Reckeweg, R. Pöttgen, R. Dronskowski*, Chem. Mater., 2024, 36, 9107–9125.[3] A. J. Corkett,* R. Dronskowski, Dalton Trans., 2019, 48, 150[4] A. J. Corkett,* Z. Chen, C. Ertural, A. Slabon, R. Dronskowski*, Inorg. Chem., 2022, 61, 18221–18228[5] H. Bourakhouadar, J. Hempelmann, J. van Leusen, A. Drichel, L. Bayarjargal, A. Koldemir, M. K. Reimann, R. Pöttgen, A. Slabon, A. J. Corkett*, R. Dronskowski*, J. Am. Chem. Soc., 2024, 146 (38), 26071–2608
Letter from R. R. Zellick, Assistant Trust Officer, Anglo California National Bank of San Francisco, to Joseph R. Goodman, October 2, 1942
No full textLetter from R. R. Zellick, Assistant Trust Officer at The Anglo California National Bank of San Francisco, to Joseph R. Goodman, regarding property owned by Dave Tatsuno. Zellick mentions a dispute between current tenants and Tatsuno, and that Tatsuno has asked Goodman to help locate trustworthy tenants.Personal correspondence, organizational records, government documents, publications, and other papers created or collected by Joseph R. Goodman documenting the forced removal and incarceration of Japanese Americans during World War II, as well as organized resistance to incarceration. Included in the collection are records of the Japanese Young Men's Christian Association and the Japanese American Citizens' League in San Francisco, including papers of the Japanese YMCA's executive secretary Lincoln Kanai; Sakai family papers; Goodman's correspondence to and from Japanese American incarcerees, organizations opposing forced removal and incarceration of Japanese Americans, the War Relocation Authority, and others; publications, photographs, and ephemera from the Topaz Relocation Center, where Goodman taught high school; War Relocation Authority records and publications; and newspaper clippings, pamphlets, and reports about forced removal and incarceration created by various government, religious, and civic organizations, in California and nationwide
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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