113,158 research outputs found
New Roads for Patron-Driven E-books:Collection Development and Technical Services Implications of a Patron-Driven Acquisitions Pilot at Rutgers
No full textCollection development librarians have long struggled to meet user demands for new titles. Too often, required resources are not purchased, while some purchased resources do not circulate. E-books selected through patron-driven plans are a solution but present new challenges for both selectors and catalogers. Radical changes to traditional technical services workflows are required, and selectors must modify the selection process to give more choice to the user. Rutgers University librarians have adopted an innovative new technical services workflow and collection-development model to manage a successful, patron-driven acquisitions project for e-books in the fields of math and computer science.This is an Accepted Manuscript of an article published by Taylor & Francis Group in Journal of Electronic Resources Librarianship on 13/12/2011, available online at: http://www.tandfonline.com/10.1080/1941126X.2011.627043
The politics of fashion: perceptions of power in female clothing and ornamentation as reflected in the sixteenth-century Chinese novel Jin Ping Mei
No full textThis thesis examines issues of female power and influence in sixteenth-century China focusing on how women and their roles were perceived in the changing social environment of the mid-late Ming dynasty. Using aspects of a New Historicist approach, information from contemporary literary and historical sources are analysed alongside each other. With its emphasis on the lives of women and preoccupation with the description of material objects, the late Ming novel Jin Ping Mei forms an important element in the thesis. China in the sixteenth century saw expanding urbanisation, the emergence of a new wealthy merchant class, increasing visibility of women and a questioning of traditional morality. Fashion consciousness, as one of the most conspicuous aspects of the new material culture, is a possible indicator of these trends. Traditional Western theories contend that fashion began in the particular context of Renaissance Europe. However, this study argues that a similar fashion awareness existed in China too, and was manifested in a competitive striving for social status, in this case specifically among women. In contrast to previous studies which downplayed the impact women had on defining traditional Chinese culture, this thesis demonstrates how women and their sartorial choices began to redefine the boundaries of material culture, influencing literati discourse which, in turn, re- influenced female behaviour
Late Holocene (2 ka) sea level, river discharge and climate interrelationship in the Taiwan region
No full textReview of Mayer, R.; Knothe, F.; Shuo, H. (2022) Reflected beauty: Chinese reverse glass paintings from the Mei Lin Collection
No full textIn this well-documented, bilingual, and richly illustrated catalogue, published for the long-anticipated exhibition Reflected Beauty: Chinese Reverse Glass Paintings from the Mei Lin Collection at the University Museum and Art Gallery of the University of Hong Kong (September 2021-January 2022), the authors give us a profound insight into the phenomenon of reverse painting on glass and mirror paintings, with a particular focus on those from the Mei Lin Collection assembled by the Sinologist, author, and translator Rupprecht Mayer and his wife Haitang Mayer-Liem. Composed of over one hundred works acquired in East Asia between 1968 and 2012, this is one of the world's most important collections of Chinese reverse glass paintings from the late nineteenth and twentieth centuries.Modern and Contemporary Studie
Covalent organic framework-supported Zn single atom catalyst for highly efficient N-formylation of amines with CO2 under mild conditions
No full textTransformation of CO2 into value-added chemicals with efficient and recyclable catalyst is an effective way to reduce carbon emissions. It is valuable to develop an efficient catalyst that can promote the N-formylation reaction under mild conditions with a high activity and excellent recyclability. Single atom catalysts (SACs) possess ultimate atom utilization efficiency and outstanding catalytic performance. Herein, we synthesize Zn SACs (Zn-TpPa) anchored on a COF (TpPa-1) using a facile solution method. Catalyzed by Zn-TpPa, CO2 and N-methylamine are transformed into N-methylformanilide under mild reaction conditions with a TOF of 17,155 h−1, which is the highest among all reported recyclable Zn-based catalysts. Zn-TpPa can also catalyze N-formylation of many other amines with excellent yields. The higher reactivity was attributable to the well-dispersed Zn active sites on COF and outstanding adsorption of CO2 owing to high surface area of COF. Our research provides a facile method for constructing SACs as well as an effective pathway for CO2 transformation and environmental protection.
Graphical abstract
Zn Single atom catalysts anchored on COF (TpPa-1) are prepared in a facile method and characterized. Zn-TpPa promotes N-formylation of N-methylaniline with CO2 and phenylsilane under mild conditions with the highest TOF among all reported recyclable Zn-catalysts. Besides, Zn-TpPa can catalyze N-formylation of many other amines with excellent yields. The work provides a facile method for constructing SACs.
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Introduction
Carbon dioxide (CO2), known as the main factor for green-house effect, has stimulated much effort to develop efficient technologies and methods for decreasing the CO2 level in the atmosphere. [[1], [2], [3], [4], [5]] As CO2 is a non-toxic, abundant, renewable C1 building block, easily available and environmentally benign feedstock, in view of green and sustainable chemistry, designing recyclable catalysts for the transformation of CO2 into value-added chemicals has recently emerged as an attractive route. [[6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18], [19], [20], [21], [22], [23]] One interesting route to fix CO2 is synthesis of formamides through N-formylation of amines using CO2 in the presence of reducing agent. Many catalysts were reported to promote this reaction. [10,16,[24], [25], [26], [27], [28], [29], [30]] However, those reported N-formylation catalysis either have a limited turnover frequency (TOF) [21,[31], [32], [33], [34], [35], [36]] or require harsh conditions, such as high reaction temperatures (>60 °C) [7,15,21,25,34,[36], [37], [38]] or high CO2 pressure (>1 Mpa) [6,7,[13], [14], [15],21,32,33,[37], [38], [39], [40]] and poor recyclability [35]. It is highly desirable to develop an efficient catalyst that can promote the N-formylation reaction under mild conditions with a high TOF and excellent recyclability.
Single-atom catalysts (SACs), containing single metal atoms anchored on solid supports, represent the utmost utilization of metallic catalysts and thus maximize catalytic reactivity. [[41], [42], [43], [44], [45]] Several fabrication processes for SACs have been reported [46], including atomic layer deposition, [47] wet chemistry [48], MOF derivative [49], potential cycling [50], acid leaching [51] and photodeposition [52]. However, they usually either require harsh conditions, such as high temperature, high pressure, acids or complicated reaction procedures. Considering the large-scale production in future industrialization, a simple and efficient way to achieve SACs is more favorable. An appropriate support is critical to interact strongly with isolated atoms, and thus prevents the movement and aggregation of isolated atoms [[53], [54], [55]], creating stable, finely dispersed active sites.
Covalent organic frameworks (COFs) represent an important type of covalent porous materials with high surface area and well-defined structures. [56,57] The periodic and permanent porosity endow COFs an excellent substrate for SACs [58]. The bottom-up synthesis using different building blocks endows COFs with tunable skeleton structure, pore size, and topology schemes [53,59,60]. With the bottom-up synthesis of COFs followed by post-metalation, it offers unprecedented opportunities for constructing SACs with well-defined catalytic centers in high metal loading [61].
Herein, we demostrate Zn single atom catalyts can be prepared on COF (TpPa-1) with high loading amount by facile dropwise adding Zn2+ solution into TpPa-1 suspension (Scheme 1) [62,63]. Catalyzed by Zn-TpPa, N-methylformanilide is produced by reacting N-methylaniline with CO2 and hydrosilanes under mild reaction conditions (1 bar CO2 pressure at room temperature) in 3 h with a TOF of 17,155 h−1, which is the highest among reported recyclable Zn-based catalysts. Besides, Zn-TpPa could catalyze N-formylation of many other amines with excellent yields. Our research provides a simple yet efficient method for constructing SACs as well as provides an effective and sustainable pathway for CO2 transformation and environmental protection.
Section snippets
Materials and characterizations
1,3,5-triformylphloroglucinol (Tp) and p-phenylenediamine (Pa-1) were purchased from Shanghai Macklin Biochemical Co. Ltd. N-methylaniline, aniline, p-toluidine, N-methyl-p-toluidine, 4-methoxy-N-methylaniline, 4-bromo-N-methylaniline, N-methylcyclohexylamine, diethylamine, pyrrolidine, morpholine, 1,2,3,4-Tetrahydro-1-methylquinoline, and phenylsilane were obtained from J&K Scientific Ltd. N, N-dimethylformamide, acetonitrile mesitylene, dioxane and methanol were obtained from Aladdin
Characterization of materials
We synthesized single atom catalysts Zn-TpPa by adding the aqueous Zn salt solution into TpPa-1 suspension (Scheme 1), which was synthesized according to the method as previously reported. [62,63] The composition of TpPa-1 and Zn-TpPa was assessed with X-ray photoelectron spectroscopy. The peaks at 1020 eV and 1045 eV in Zn 2p XPS (Fig. S1d) spectrum indicated the presence of Zn element in Zn-TpPa. Besides, the Zn loading in the Zn-TpPa reached 0.5 wt%, as determined by inductively coupled
Conclusion
In conclusion, Zn single atom catalyst on COF with high loading were facially prepared. Zn-TpPa showed excellent catalyst activity, selectivity and recyclability for N-formation under mild condition with CO2 and phenysilane. It showed the highest TOF normalized to single Zn sites as 17,155 h−1 among all reported Zn-based catalysts. Importantly, Zn-TpPa showed the highest TOF among all reported catalysts which promoted N-formylation of N-methylaniline with CO2 and hydrosilanes with good
CRediT authorship contribution statement
Qiang Cao: Investigation, Conceptualization, Writing - original draft. Long-Long Zhang: Data curation. Chang Zhou: Resources. Jing-Hui He: Supervision, Writing - review & editing, Funding acquisition. Antonio Marcomini: Writing - review & editing. Jian-Mei Lu: Resources, Writing - review & editing, Supervision, Funding acquisition.
Declaration of Competing Interest
The authors report no declarations of interest.
Acknowledgements
We gratefully acknowledge the financial support provided by National Natural Science Foundation of China (21978185, 21938006, 21776190), the National Key R&D Program of China (2020YFC1818401, 2017YFC0210906), Basic Research Project of Leading Technology in Jiangsu Province (BK20202012), Suzhou Science and Technology Bureau Project (SYG201935) and the project supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
Frankfurt book fair: cancelled prize ceremony for Palestinian author is part of a long history of political zigzagging
No full textFirst paragraph: The Frankfurt Buchmesse, or book fair, is the world’s largest publishing industry gathering, attracting thousands of exhibitors every October. On one level, it’s a business event focused on creating buzz for forthcoming bestsellers, trading rights and discussing industry developments. On another, it’s a public celebration of books and the values associated with them.https://theconversation.com/frankfurt-book-fair-cancelled-prize-ceremony-for-palestinian-author-is-part-of-a-long-history-of-political-zigzagging-21574
Early Holocene catastrophic mass-wasting event and fan-delta development on the Hua-tung coast, eastern Taiwan
No full textExploring the associations between long-term care and mortality rates among stroke patients.
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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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