1,720,965 research outputs found
Long-range corrected meta-generalized-gradient approximations
No full textKohn–Sham 密度泛函理論已成為最廣泛應用的電子結構理論之一。但理論中
的重要部分，交換–相關能泛函仍未確知，並且需要近似。真實的交換–相關電洞
是完全非局域性的。加入了 Hartree-Fock (HF)交換能的混成密度泛函增加了模型中的非局域性。混成高階密度泛函已被證實可以表現得比混成廣義密度梯度近似還要好。長程修正的(LC)混成泛函只對於長程的電子–電子交互作用保留完整的 HF交換能，因而解決了一大部分的自我作用問題。
藉由將一個系統化地模擬 LC 混成密度泛函的方法應用到 M05 混成高階交換–相關泛函的形式，並加入經驗的原子–原子分散修正，吾人發表了一個新的 LC 高階廣義密度梯度近似，稱為 ωM05-D，可適用於熱化學、熱化學動力學以及非共價交互作用。測試顯示，對於大部分的應用，ωM05-D 之於 M05-2X 泛函，展現了可觀的改善。若和 LC 廣義密度梯度近似 ωB97X-D 比較，ωM05-D 展現了較小的自我作用誤差，與較佳的漸近特性。Kohn–Sham density-functional theory (KS-DFT) has become one of the most popular electronic structure theories. However, its crucial ingredient, the exact exchange-correlation energy functional remains unknown and needs to be approximated. The exact exchange-correlation hole is fully nonlocal. Hybrid density functionals, which incorporate Hartree-Fock (HF) exchange, can help to include nonlocality. Hybrid meta density functionals have been shown capable of performing better than hybrid generalized gradient approximation (GGA). Long-range corrected (LC) hybrids retain full HF exchange only for long-range electron-electron interactions, and thereby resolve a significant part of the self-interaction problems.
By applying a general scheme for systematically modeling LC hybrid density functionals to the form of hybrid meta exchange-correlation functional M05, and including empirical atom-atom dispersion corrections, we present a new LC meta-GGA, called ωM05-D, for thermochemistry, thermochemical kinetics, and noncovalent interactions. Tests show that for most applications, ωM05-D exhibits noticeable improvement over the M05-2X functional. When compared to the LC-GGA, ωB97X-D, ωM05-D exhibits smaller self-interaction error (SIE) and better asymptotic behavior
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe 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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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