1,721,008 research outputs found
Ternary NiS/Zn(x)cd(1-x)S/reduced graphene oxide nanocomposites for enhanced solar photocatalytic h(2)-production activity
No full textZnₓCd₁-ₓS solid solutiosnA ternary ZnₓCd₁-xS-based material in the co-presence of NiS and reduced graphene oxide (RGO) is designed and synthesized. It shows a high solar photocatalytic H2-production activity and the apparent quantum efficiency of 31.1% at 420 nm. This represents one of the most active metal sulfide photocatalysts in the absence of noble-metal cocatalysts and the significantly improved performance can be attributed to the positive synergetic effect of NiS and RGO over ZnₓCd₁ₓS.Jun Zhang, Lifang Qi, Jingrun Ran, Jiaguo Yu, and Shi Zhang Qia
Photocatalytic carbon dioxide Reduction: Identification and Elimination of False-Positive Results
No full textNo abstract availableYanzhao Zhang, Dazhi Yao, Bingquan Xia, Mietek Jaroniec, Jingrun Ran, and Shi-Zhang Qia
Scalable self-supported graphene foam for high-performance electrocatalytic oxygen evolution
No full textDeveloping efficient electrocatalysts consisting of earth-abundant elements for oxygen evolution reaction (OER) is crucial for energy devices and technologies. Herein, we report self-supported highly porous nitrogen-doped graphene foam synthesized through the electrochemical expansion of carbon-fiber paper and subsequent nitrogen plasma treatment. A thorough characterization, such as electron microscopy and synchrotron-based near-edge X-ray absorption fine structure, indicates the well-developed porous structures featuring homogeneously doped nitrogen heteroatoms. These merits ensure enriched active sites, an enlarged active surface area, and improved mass/electron transport within the continuous graphene framework, thus leading to an outstanding capability toward electrocatalyzing OER in alkaline media, even competitive with the state-of-the-art noble-/transition-metal and nonmetal electrocatalysts reported to date, from the perspectives of the sharp onset potential, a small Tafel slope, and remarkable durability. Furthermore, a rechargeable Zn-air battery with this self-supported electrocatalyst directly used as the air cathode renders a low charge/discharge overpotential and considerable life span. The finding herein suggests that a rational methodology to synthesize graphene-based materials can significantly enhance the oxygen electrocatalysis, thereby promoting the overall performance of the energy-related system.Yun-Pei Zhu, Jingrun Ran and Shi-Zhang Qia
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
Facet-specific Active Surface Regulation of BixMOy (M=Mo, V, W) Nanosheets for Boosted Photocatalytic CO2 reduction
Full text linkPublished 12 December 2022Photocatalytic performance can be optimized via introduction of reactive sites. However, it is practically difficult to engineer these on specific photocatalyst surfaces, because of limited understanding of atomic-level structure-activity. Here we report a facile sonication-assisted chemical reduction for specific facets regulation via oxygen deprivation on Bi-based photocatalysts. The modified Bi2MoO6 nanosheets exhibit 61.5 and 12.4 μmol g-1 for CO and CH4 production respectively, ~3 times greater than for pristine catalyst, together with excellent stability/reproducibility of ~20 h. By combining advanced characterizations and simulation, we confirm the reaction mechanism on surface-regulated photocatalysts, namely, induced defects on highly-active surface accelerate charge separation/transfer and lower the energy barrier for surface CO2 adsorption/activation/reduction. Promisingly, this method appears generalizable to a wider range of materials.Yanzhao Zhang, Xing Zhi, Jeffrey R. Harmer, Haolan Xu, Kenneth Davey, Jingrun Ran, and Shi-Zhang Qia
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
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