arXiv subjects

Weishu Liu

Publications and source records attributed to Weishu Liu.

At least 19 recordsLinked to original sources

arXiv2025

Red alert: Millions of "homeless" publications in Scopus should be resettled

Scopus is increasingly regarded as a high-quality and reliable data source for research and evaluation of scientific and scholarly activity. However, a puzzling phenomenon has been discovered occasionally: millions of records with author affiliation information collected in Scopus are oddly labeled as "country-undefined" by Scopus which is rarely to be detected in its counterpart Web of Science. This huge number of "homeless" records in Scopus is unacceptable for a widely used high-quality bibliographic database. By using data from the past 124 years, this brief communication tries to probe these affiliated but country-undefined records in Scopus. Our analysis identifies four primary causes for these "homeless" records: incomplete author affiliation addresses, Scopus' inability to recognize different variants of country/territory names, misspelled country/territory names in author affiliation addresses, and Scopus' insufficiency in correctly split and identify the clean affiliation addresses. To address this pressing issue, we put forward several recommendations to relevant stakeholders, with the aim of resettling millions of "homeless" records in Scopus and reducing its potential impact on Scopus-based literature retrieval, analysis, and evaluation.

cs.DL↗

arXiv2025

Functional Unit: A New Perspective on Materials Science Research Paradigms

New materials have long marked the civilization level, serving as an impetus for technological progress and societal transformation. The classic structure-property correlations were key of materials science and engineering. However, the knowledge of materials faces significant challenges in adapting to exclusively data-driven approaches for new material discovery. This perspective introduces the concepts of functional units (FUs) to fill the gap in understanding of material structure-property correlations and knowledge inheritance as the "composition-microstructure" paradigm transitions to a data-driven AI paradigm transitions. Firstly, we provide a bird's-eye view of the research paradigm evolution from early "process-structure-properties-performance" to contemporary data-driven AI new trend. Next, we highlight recent advancements in the characterization of functional units across diverse material systems, emphasizing their critical role in multiscale material design. Finally, we discuss the integration of functional units into the new AI-driven paradigm of materials science, addressing both opportunities and challenges in computational materials innovation.

cond-mat.mtrl-sci↗

arXiv2024

Emerging quantum critical phase in a cluster spin-glass

Magnetic frustration has been recognized as pivotal to investigating new phases of matter in correlation-driven Kondo breakdown quantum phase transitions that are not clearly associated with broken symmetry. The nature of these new phases, however, remains underexplored. Here, we report quantum criticalities emerging from a cluster spin-glass in the heavy-fermion metal TiFe$_x$Cu$_{2x-1}$Sb, where frustration originates from intrinsic disorder. Specific heat and magnetic Grüneisen parameter measurements under varying magnetic fields exhibit quantum critical scaling, indicating a quantum critical point near 0.13 Tesla. As the magnetic field increases, the cluster spin-glass phase is progressively suppressed. Upon crossing the quantum critical point, resistivity and Hall effect measurements reveal enhanced screening of local moments and an expanding Fermi surface, consistent with the Kondo breakdown scenario.

cond-mat.str-el↗

arXiv2023

Web of Science Core Collection's coverage expansion:The forgotten Arts & Humanities Citation Index?

The expansion of Web of Science Core Collection (WoSCC) over the recent years has partially accounted for the "norm" of growth of research output in many bibliometric analysis studies. However, the expansion patterns of different citation indexes may be different, which may benefit some disciplines but hinder others. Utilizing Science Citation Index Expanded (SCIE), Social Sciences Citation Index (SSCI), and Arts & Humanities Citation Index (A&HCI), this study attempts to elaborate on WoSCC's coverage expansion patterns among these three databases from 2001 to 2020. Results show that different from SCIE/SSCI, both the annual publication volumes in the A&HCI database and all A&HCI journals have remained relatively stagnant in all document types considered scenario or have gained relatively slight increases in only citable items considered scenario. Although the number of A&HCI journals also has increased remarkably, the average journal publication volume of A&HCI journals has decreased gradually if all document types are considered or kept relatively stagnant when citable items only are considered. Besides, the A&HCI database has ceased the systematic index of individually selected items from SCIE/SSCI journals since 2018. The study finally discusses the possible causes and consequences of the unbalanced expansion of WoSCC's different citation indexes.

cs.DL↗

arXiv2023

Citation advantage of COVID-19 related publications

With the global spread of the COVID-19 pandemic, scientists from various disciplines responded quickly to this historical public health emergency. The sudden boom of COVID-19 related papers in a short period of time may bring unexpected influence to some commonly used bibliometric indicators. By a large-scale investigation using Science Citation Index Expanded and Social Sciences Citation Index, this brief communication confirms the citation advantage of COVID-19 related papers empirically through the lens of Essential Science Indicators' highly cited paper. More than 8% of COVID-19 related papers published during 2020 and 2021 were selected as Essential Science Indicators highly cited papers, which was much higher than the set global benchmark value of 1%. The citation advantage of COVID-19 related papers for different Web of Science categories/countries/journal impact factor quartiles were also demonstrated. The distortions of COVID-19 related papers' citation advantage to some bibliometric indicators such as journal impact factor were discussed at the end of this brief communication.

cs.DL↗

arXiv2022

A topological transition-induced giant transverse thermoelectric effect in polycrystalline Dirac semimetal Mg3Bi2

To achieve thermoelectric energy conversion, a large transverse thermoelectric effect in topological materials is crucial. However, the general relationship between topological electronic structures and transverse thermoelectric effect remains unclear, restricting the rational design of novel transverse thermoelectric materials. Herein, we demonstrate a topological transition-induced giant transverse thermoelectric effect in polycrystalline Mn-doped Mg3+δBi2 material, which has a competitively large transverse thermopower (617 uV/K), power factor (20393 uWm-1K-2), magnetoresistance (16600%), and electronic mobility (35280cm2V-1S-1). The high performance is triggered by the modulation of chemical pressure and disorder effects in the presence of Mn doping, which induces the transition from a topological insulator to a Dirac semimetal. The high-performance polycrystalline Mn-doped Mg3+δ Bi2 described in this work robustly boosts transverse thermoelectric effect through topological phase transition, paving a new avenue for the material design of transverse thermoelectricity.

cond-mat.mtrl-sci↗

arXiv2022

Solid-state Janus nanoprecipitation enables amorphous-like heat conduction in crystalline Mg3Sb2-based thermoelectric materials

Solid-state precipitation can be used to tailor materials properties, ranging from ferromagnets and catalysts to mechanical strengthening and energy storage. Thermoelectric properties can be modified by precipitation to enhance phonon scattering while retaining charge-carrier transmission. Here, we uncover unconventional dual Janus-type nanoprecipitates in Mg3Sb1.5Bi0.5 formed by side-by-side Bi- and Ge-rich appendages, in contrast to separate nanoprecipitate formation. These Janus nanoprecipitates result from local co-melting of Bi and Ge during sintering, enabling an amorphous-like lattice thermal conductivity. A precipitate size effect on phonon scattering is observed due to the balance between alloy-disorder and nanoprecipitate scattering. The thermoelectric figure-of-merit ZT reaches 0.6 near room temperature and 1.6 at 773 K. The Janus nanoprecipitation can be introduced into other materials and may act as a general property-tailoring mechanism.

cond-mat.mtrl-sci↗

arXiv2022

Giant transverse and longitudinal magneto-thermoelectric effect in polycrystalline nodal-line semimetal Mg3Bi2

Topological semimetals provide new opportunities for exploring new thermoelectric phenomena, because of their exotic and nontrivial electronic structure topology around the Fermi surface. In this study, we report on the discovery of giant transverse and longitudinal magneto-thermoelectric (MTE) effects in Mg3Bi2, which is predicted to be a type-II nodal-line semimetal in the absence of spin-orbit coupling (SOC). The maximum transverse power factor is 2182 μWm^{-1}K^{-2} at 13.5 K and 6 Tesla. The longitudinal power factor reaches up to 3043μWm^{-1}K^{-2} at 15 K and 13 Tesla, which is 20 times higher than in a zero-strength magnetic field and is also comparable to state-of-the-art MTE materials. By compensating Mg loss in the Mg-rich conditions for turning carrier concentration, the sample obtained in this work shows a large linear non-saturating magnetoresistance of 940% under a field of 14 Tesla. This is a two-orders-of-magnitude increase with respect to the normal Mg-deficiency Mg3Bi2 sample. Using density functional calculations, we attribute the underlying mechanism to the parent nodal-line electronic structure without SOC and the anisotropic Fermi surface shape with SOC, highlighting the essential role of high carrier mobility and open electron orbits in moment space. Our work offers a new avenue toward highly efficient thermoelectric materials through the design of Fermi surfaces with special topological electronic structures in novel quantum materials.

cond-mat.mtrl-sci↗

arXiv2021

Caveats for the use of Web of Science Core Collection in old literature retrieval and historical bibliometric analysis

By using publications from Web of Science Core Collection (WoSCC), Fosso Wamba and his colleagues published an interesting and comprehensive paper in Technological Forecasting and Social Change to explore the structure and dynamics of artificial intelligence (AI) scholarship. Data demonstrated in Fosso Wamba's study implied that the year 1991 seemed to be a "watershed" of AI research. This research note tried to uncover the 1991 phenomenon from the perspective of database limitation by probing the limitations of search in abstract/author keywords/keywords plus fields of WoSCC empirically. The low availability rates of abstract/author keywords/keywords plus information in WoSCC found in this study can explain the "watershed" phenomenon of AI scholarship in 1991 to a large extent. Some other caveats for the use of WoSCC in old literature retrieval and historical bibliometric analysis were also mentioned in the discussion section. This research note complements Fosso Wamba and his colleagues' study and also helps avoid improper interpretation in the use of WoSCC in old literature retrieval and historical bibliometric analysis.

cs.DL↗

arXiv2020

A matter of time: publication dates in Web of Science Core Collection

Web of Science Core Collection, one of the most authoritative bibliographic databases, is widely used in academia to track high-quality research. This database has begun to index online-first articles since December 2017. This new practice has introduced two different publication dates (online and final publication dates) into the database for more and more early access publications. It may confuse many users who want to search or analyze literature by using the publication-year related tools provided by Web of Science Core Collection. By developing custom retrieval strategies and checking manually, this study finds that the "year published" field in search page searches in both online and final publication date fields of indexed records. Each indexed record is allocated to only one "publication year" on the left of the search results page which will inherit first from online publication date field even when the online publication date is later than the final publication date. The "publication year" field in the results analysis page and the timespan "custom year range" field in the search page have the same function as that of the filter "publication year" in search results page. The potential impact of the availability of two different publication dates in calculating bibliometric indicators is also discussed at the end of the article.

cs.DL↗

arXiv2020

China's SCI-indexed publications: facts, feelings, and future directions

Purpose:In relation to the boom in China's SCI-indexed publications, this opinion piece examines this phenomenon and looks at future possible directions for the reform of China's research evaluation processes. Design/Approach/Methods:This opinion piece uses bibliographic data for the past decade (2010-2019) from the Science Citation Index Expanded in the Web of Science Core Collection to examine the rise in China's SCI-indexed publications. Findings: China has surpassed the United States and been the largest contributor of SCI publications since 2018. However, while the impact of China's SCI publications is rising, the scale of this impact still lags behind that of other major contributing countries. China's SCI publications are also overrepresented in some journals. Originality/Value: Reporting the latest facts about China's SCI-indexed publications, this article will benefit the reform of China's research evaluation system.

cs.DL↗

arXiv2020

Comparing like with like: China ranks first in SCI-indexed research articles since 2018

China's rising in scientific research output is impressive. The academic community is curious about the time when the cross-over in the number of annual scientific publication production between China and the USA can happen. By using Web of Science Core Collection's Science Citation Index Expanded database, this study finds that China still ranks the second in the production of SCI-indexed publications in 2019 but may leapfrog the USA to be the first in 2020 or 2021, if all document types are considered. Comparatively, China has already overtaken the USA and been the largest SCI-indexed original research article producer since 2018. However, China still lags behind the USA regarding the number of review paper production. In general, quantitative advantage does not equal quality or impact advantage. We think that the USA will continue to be the global scientific leader for a long time.

cs.DL↗

arXiv2020

A tale of two databases: The use of Web of Science and Scopus in academic papers

Web of Science and Scopus are two world-leading and competing citation databases. By using the Science Citation Index Expanded and Social Sciences Citation Index, this paper conducts a comparative, dynamic, and empirical study focusing on the use of Web of Science (WoS) and Scopus in academic papers published during 2004 and 2018. This brief communication reveals that although both Web of Science and Scopus are increasingly used in academic papers, Scopus as a new-comer is really challenging the dominating role of WoS. Researchers from more and more countries/regions and knowledge domains are involved in the use of these two databases. Even though the main producers of related papers are developed economies, some developing economies such as China, Brazil and Iran also act important roles but with different patterns in the use of these two databases. Both two databases are widely used in meta-analysis related studies especially for researchers in China. Health/medical science related domains and the traditional Information Science & Library Science field stand out in the use of citation databases.

cs.DL↗

arXiv2020

Funding information in Web of Science: An updated overview

Despite the limitations of funding acknowledgment (FA) data in Web of Science (WoS), studies using FA information have increased rapidly over the last several years. Considering this WoS'recent practice of updating funding data, this paper further investigates the characteristics and distribution of FA data in four WoS journal citation indexes. The research reveals that FA information coverage variances persist cross all four citation indexes by time coverage, language and document type. Our evidence suggests an improvement in FA information collection in humanity and social science research. Departing from previous studies, we argue that FA text (FT) alone no longer seems an appropriate field to retrieve and analyze funding information, since a substantial number of documents only report funding agency or grant number information in respective fields. Articles written in Chinese have a higher FA presence rate than other non-English WoS publications. This updated study concludes with a discussion of new findings and practical guidance for the future retrieval and analysis of funded research.

cs.DL↗

arXiv2018

Mg$_{3+δ}$Sb$_x$Bi$_{2-x}$ family: A promising substitute for the start-of-art n-type thermoelectric materials near room temperature

Bi2Te3-xSex family has been the n-type start-of-the-art thermoelectric materials near room temperatures (RT) for more than half-century, which dominates the active cooling and novel waves harvesting application near RT. However, the drawbacks of brittle nature and Te-containing restrict the further applications exploring. Here, we show that a Mg3+δSbxBi2-x family ((ZT)avg =1.05) could be a promising substitute for the Bi2Te3-xSex family ((ZT)avg =0.9-1.0) in the temperature range of 50-250 °C based on the comparable thermoelectric performance through a synergistic effect from the tunable band gap using the alloy effect and the suppressible Mg-vacancy formation using interstitial Mn dopant. The former is to shift the optimal thermoelectric performance to near RT, and latter is helpful to partially decouple the electrical transport and thermal transport in order to get an optimal RT power factor. A positive temperature-dependence of band gap suggested this family is also a superior medium-temperature thermoelectric material for the significantly suppressed bipolar effect. Furthermore, a two times higher mechanical toughness, compared with Bi2Te3-xSex family, consolidates the promising substitute for the start-of-art n-type thermoelectric materials near RT.

cond-mat.mtrl-sci↗

arXiv2018

Missing author address information in Web of Science-An explorative study

Bibliometric analysis is increasingly used to evaluate and compare research performance across geographical regions. However, the problem of missing information from author addresses has not attracted sufficient attention from scholars and practitioners. This study probes the missing data problem in the three core journal citation databases of Web of Science (WoS). Our findings reveal that from 1900 to 2015 over one-fifth of the publications indexed in WoS have completely missing information from the address field. The magnitude of the problem varies greatly among time periods, citation databases, document types, and publishing languages. The problem is especially serious for research in the sciences and social sciences published before the early 1970s and remains significant for recent publications in the arts and humanities. Further examinations suggest that many records with completely missing address information do not represent scholarly research. Full-text scanning of a random sample reveals that about 40% of the articles have some address information that is not indexed in WoS. This study also finds that the problem of partially missing address information for U.S. research has diminished dramatically since 1998. The paper ends by providing some discussion and tentative remedies.

cs.DL↗

arXiv2018

Book reviews in academic journals: patterns and dynamics

Book reviews play important roles in scholarly communication especially in arts and humanities disciplines. By using Web of Science's Science Citation Index Expanded, Social Sciences Citation Index, and Arts & Humanities Citation Index, this study probed the patterns and dynamics of book reviews within these three indexes empirically during the past decade (2006-2015). We found that the absolute numbers of book reviews among all the three indexes were relatively stable but the relative shares were decreasing. Book reviews were very common in arts and humanities, common in social sciences, but rare in natural sciences. Book reviews are mainly contributed by authors from developed economies such as the USA and the UK. Oppositely, scholars from China and Japan are unlikely to contribute to book reviews.

cs.DL↗

arXiv2017

The effect of publishing a highly cited paper on journal's impact factor: a case study of the Review of Particle Physics

A single highly cited article can give a big but temporary lift in its host journal's impact factor evidenced by the striking example of "A short history of SHELX" published in Acta Crystallographica Section A. By using Journal Citation Reports and Web of Science's citation analysis tool, we find a more general and continuous form of this phenomenon in the Particle Physics field. The highly-cited "Review of Particle Physics" series have been published in one of the major Particle Physics journals biennially. This study analyses the effect of these articles on the Impact Factor (IF) of the host journals. The results show that the publication of Review of Particle Physics articles has a direct effect of lifting the IF of its host journal. However the effect on the IF varies according to whether the host journal already has a relatively high or low IF, and the number of articles that it publishes. The impact of these highly cited articles clearly demonstrates the limitations of journal impact factor, and endorses the need to use it more wisely when deciding where to publish and how to evaluate the relative impact of a journal.

cs.DL↗