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- Yang, Guoliang, et al.
(författare)
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Using multi-level frontiers in DEA models to grade countries/territories
- 2016
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Ingår i: Journal of Informetrics. - : Elsevier. - 1751-1577 .- 1875-5879. ; 10:1, s. 238-253
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Tidskriftsartikel (refereegranskat)abstract
- Several investigations to and approaches for categorizing academic journals/institutions/countries into different grades have been published in the past. To the best of our knowledge, most existing grading methods use either a weighted sum of quantitative indicators (including the case of one properly defined quantitative indicator) or quantified peer review results. Performance measurement is an important issue of concern for science and technology (S&T) management. In this paper we address this issue, leading to multi-level frontiers resulting from data envelopment analysis (DEA) models to grade selected countries/territories. We use research funding and researchers as input indicators, and take papers, citations and patents as output indicators. Our research results show that using DEA frontiers we can unite countries/territories by different grades. These grades reflect the corresponding countries' levels of performance with respect to multiple inputs and outputs. Furthermore, we use papers, citations and patents as single output (with research funding and researchers as inputs), respectively, to show country/territory grade changes. In order to increase the insight in this approach, we also incorporate a simple value judgment (that the number of citations is more important than the number of papers) as prior information into the DEA models to study the resulting changes of these Countries/Territories' performance grades.
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| 3. |
- Ahlgren, Per, et al.
(författare)
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The role of the Chinese Key Labs in the international and national scientific arena revisited
- 2017
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Ingår i: Research Evaluation. - : OXFORD UNIV PRESS. - 0958-2029 .- 1471-5449. ; 26:2, s. 132-143
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Tidskriftsartikel (refereegranskat)abstract
- In this contribution, which builds on and develops a study that was published more than 10 years ago, we address the role of the Chinese Key Labs (KLs) in the international and national scientific arena. We give a short overview of the position of KLs in China, including their budget and manpower. Based on large numbers of Chinese publications obtained from the Web of Science (WoS) and the Chinese Science Citation Database (CSCD), the KLs are compared across publication years to the rest of China (ChRest) with respect to publication output and citation impact. We also look at collaboration in terms of co-publishing between the KLs and the ChRest. As to publications in the WoS, we found that the contribution of KLs compared with the ChRest is slightly and irregularly increasing (using full counting as well as fractional counting), whereas a stronger increasing trend is observed for the corresponding contribution in the CSCD. We observed an increase in the number of collaborations between KLs and Chinese colleagues, regardless of database. For WoS and field normalized citation indicators, we obtained the expected results that researchers at KLs perform considerably better than other Chinese colleagues and, moreover, perform clearly better than database average. As such we may conclude that KLs have lived up to their promise and made real impact on the international arena.
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| 4. |
- Ding, Jielan, et al.
(författare)
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Disciplinary structures in Nature, Science and PNAS : journal and country levels
- 2018
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Ingår i: Scientometrics. - : SPRINGER. - 0138-9130 .- 1588-2861. ; 116:3, s. 1817-1852
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Tidskriftsartikel (refereegranskat)abstract
- This paper analyzes, using Web of Science publications and two time periods (2004-2006 and 2014-2016), the disciplinary structures in the three prestigious journals Nature, Science and PNAS, compared with two baselines: Non-NSP_Multi (multidisciplinary publications that have other source journals than Nature, Science and PNAS), and Non-Multi (publications assigned to other categories than Multidisciplinary). We analyze the profiles at two levels, journal and country. The results for the journal level show that for Nature and Science, the publications are considerably less concentrated to certain disciplines compared to PNAS. Biology is the dominant discipline for all the three journals. Nature and Science have similar publication shares in Medicine, Geosciences, Physics, Space science, and Chemistry. The publications of PNAS are highly concentrated to two disciplines: Biology and Medicine. Compared with Non-NSP_Multi and Non-Multi, the shares of Biology in NSP journals are higher, whereas the share of Medicine is lower. At the country level, 14 countries are included, among them the five BRICS countries. With respect to the NSP journals, the emphasis disciplines (in terms of world share of publications) of most countries other than USA are the disciplines in which USA has its weakest performance. The disciplinary structures of USA and of most of the other studied countries therefore tend to be different. Regarding Non-NSP_Multi and Non-Multi, the shapes of the disciplinary structures of the 14 countries can be roughly grouped into three groups, while there are more types of shapes for the countries in the NSP journals. For all five units of analysis, the discipline structures of most countries generally change only slightly between different time periods. The structures of some BRICS countries, however, change to a relatively large extent.
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| 5. |
- Wang, Yaling, et al.
(författare)
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Enhanced performance and stability of inverted planar perovskite solar cells by incorporating 1,6-diaminohexane dihydrochloride additive
- 2018
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Ingår i: Solar Energy Materials and Solar Cells. - : ELSEVIER SCIENCE BV. - 0927-0248 .- 1879-3398. ; 188, s. 140-148
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Tidskriftsartikel (refereegranskat)abstract
- Herein, 1,6-Diaminohexane Dihydrochloride (1,6-DD) is introduced into perovskite precursors to fabricate the inverted planar perovskite solar cells. By regulating the concentration of 1,6-DD additive, the average power conversion efficiency (PCE) of perovskite solar cells is enhanced by 20%. The champion device achieves a relatively high PCE of 17% and an excellent fill factor of 80.1%. The PCE of the large-area (1 cm(2)) device also reaches to 13.68%. After exposure to the air for 16 days, the device with 1,6-DD additive still retains above 90% of the initial efficiency, exhibiting good stability. We demonstrate that a small amount of 1,6-DD affects the crystallization dynamic, yielding ideal perovskite film with enhanced crystallinity and enlarged grain size. The two terminal -NH3+ groups passivates the vacancy defects at the perovskite crystal surface, suppressing charge recombination and facilitating charge transportation effectively. Meanwhile, adjacent crystal surfaces are linked through the hexane alkyl chain of 1,6-DD molecule, which enhances the interaction between perovskite grains and anchors the microstructure of perovskite to some degree. Hydrophobic hexane alkyl chains also increase the moisture resistance of perovskite film. Thus, an easy and effective way is provided for fabricating efficient and stable perovskite solar cells.
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