Showing papers by "Hai Yu published in 2023"
TL;DR: In this article , a sea urchin-shaped Na2Ti3O7 material was used as an anode material for lithium-ion battery application, which can better contact with the electrolyte and increase the active site number.
1 citations
TL;DR: Li et al. as discussed by the authors designed a series of anode materials with the general formula of Li2ZnTi3O8 (LZTO) and Li2-xZn Ti3-xNbxO8(LZTNO) (x = 0.2, 0.4, and 0.5)
Abstract: A series of anode materials with the general formula of Li2ZnTi3O8 (LZTO) and Li2-xZnTi3-xNbxO8 (x = 0.2, 0.4, and 0.5) (LZTNO) are designed. Different amount of high valence Nb5+ dopants not only reduces the content of lithium in LZTO but also alters the intrinsic characteristics of the composites, leading to optimized electrochemical performances. XRD, SEM, TEM, and XPS results suggest that Nb dopants are introduced successfully, but large amount of Nb5+ dopants (x > 0.2) result in the formation of ZnNb2O6 and TiO2. Owing to the small particle size and the improved structural stability, LZTNO-2 sample exhibits the best electrochemical performance, and it can deliver a charge/discharge capacity of 182.7/181.2 mAh g−1 at 1 A g−1 after 500 cycles, which is much higher than the value of LZTO (100.41/100.41 mAh g−1). The experiments suggest that the introduction of high valence dopants can effectively modulate the stoichiometry and lithium content of the anode materials, making the available vacant sites for subsequent intercalation of lithium obviously extended. Such a strategy is expected to be feasibly applied to other anode materials to enhance their specific capacity and electrochemical performances.
TL;DR: In this article , the thermodynamic and kinetic stabilities of the [Be,N,C,O] isomers were predicted using the isomerization reaction potential using coupled-cluster methods.
Abstract: This study investigates the [Be,N,C,O] system by employing density functional theory and coupled-cluster methods. The thermodynamic and kinetic stabilities of the [Be,N,C,O] isomers are predicted using the isomerization reaction potential...
TL;DR: In this paper , a mechanochemical grinding approach assisted by oleylamine as an additive to restore the optical properties and photocatalytic activity of deactivated CsPbBr3 nanocrystals was developed.
Abstract: CsPbBr3 perovskite nanocrystals have emerged as promising candidates for photocatalysis. However, their conversion efficiency is hampered by material instability, and the accumulation of deactivated perovskites produced after photocatalytic reactions raises significant environmental concerns. To address this issue, we developed a mechanochemical grinding approach assisted by oleylamine as an additive to restore the optical properties and photocatalytic activity of deactivated CsPbBr3, which was due to aggregation in the photocatalytic CO2 reduction reaction. Upon regeneration, the CsPbBr3 nanocrystals exhibited an average length of 34.21 nm and an average width of 20.86 nm, demonstrating optical properties comparable to those of the pristine CsPbBr3 nanocrystals. Moreover, they achieved a conversion efficiency of 88.7% compared with pristine CsPbBr3 nanocrystals in the photocatalytic CO2 reduction reaction. This method effectively enhanced the utilization of CsPbBr3, offering a novel approach for the recycling and recovery of perovskite materials and thereby minimizing material waste and environmental pollution.
TL;DR: In this article , the authors conducted an empirical study to learn the scale of packages that block the propagation of vulnerability fixes in the npm ecosystem and investigate their evolution characteristics, and they proposed an ecosystem-level technique, Plumber, for deriving feasible remediation strategies to boost the propagated vulnerability fixes.
Abstract: Vulnerabilities are known reported security threats that affect a large amount of packages in the npm ecosystem. To mitigate these security threats, the open-source community strongly suggests vulnerable packages to timely publish vulnerability fixes and recommends affected packages to update their dependencies. However, there are still serious lags in the propagation of vulnerability fixes in the ecosystem. In our preliminary study on the latest versions of 356,283 active npm packages, we found that 20.0% of them can still introduce vulnerabilities via direct or transitive dependencies although the involved vulnerable packages have already published fix versions for over a year. Prior study by (Chinthanet et al. 2021) lays the groundwork for research on how to mitigate propagation lags of vulnerability fixes in an ecosystem. They conducted an empirical investigation to identify lags that might occur between the vulnerable package release and its fixing release. They found that factors such as the branch upon which a fix landed and the severity of the vulnerability had a small effect on its propagation trajectory throughout the ecosystem. To ensure quick adoption and propagation of a release that contains the fix, they gave several actionable advice to developers and researchers. However, it is still an open question how to design an effective technique to accelerate the propagation of vulnerability fixes. Motivated by this problem, in this paper, we conducted an empirical study to learn the scale of packages that block the propagation of vulnerability fixes in the ecosystem and investigate their evolution characteristics. Furthermore, we distilled the remediation strategies that have better effects on mitigating the fix propagation lags. Leveraging our empirical findings, we propose an ecosystem-level technique, Plumber, for deriving feasible remediation strategies to boost the propagation of vulnerability fixes. To precisely diagnose the causes of fix propagation blocking, Plumber models the vulnerability metadata, and npm dependency metadata and continuously monitors their evolution. By analyzing a full-picture of the ecosystem-level dependency graph and the corresponding fix propagation statuses, it derives remediation schemes for pivotal packages. In the schemes, Plumber provides customized remediation suggestions with vulnerability impact analysis to arouse package developers’ awareness. We applied Plumber to generating 268 remediation reports for the identified pivotal packages, to evaluate its remediation effectiveness based on developers’ feedback. Encouragingly, 47.4% our remediation reports received positive feedback from many well-known npm projects, such as Tensorflow/tfjs, Ethers.js, and GoogleChrome/workbox. Our reports have boosted the propagation of vulnerability fixes into 16,403 root packages through 92,469 dependency paths. On average, each remediated package version is receiving 72,678 downloads per week by the time of this work.
TL;DR: In this paper , a novel Z-scheme heterojunction is fabricated via the Cd0.3Zn0.7S twin crystal and the narrow band gap semiconductor Ag3PO4.
Abstract: To improve the photocatalytic performance of semiconductor catalysts, one of the most widely used strategies is to combine two or more semiconductors with appropriate energy band structures to construct heterojunctions for an extended light absorption range and effective charge separation. Here, a novel Z-scheme heterojunction is fabricated via the Cd0.3Zn0.7S twin crystal and the narrow band gap semiconductor Ag3PO4. The resulting Cd0.3Zn0.7S/1%Ag3PO4 photocatalyst exhibits excellent photocatalytic hydrogen production capability (167.29 μmol h-1), which is two times higher than that of Cd0.3Zn0.7S and 44/7 times higher than that of pristine ZnS/CdS. The excellent photocatalytic performance is not only attributed to the defective twin crystal structure of Cd0.3Zn0.7S but also related to the well-matched Z-scheme interface between Cd0.3Zn0.7S and Ag3PO4, and both factors effectively promote the separation of the photogenerated electron-hole pairs and prolong the lifetime of the carriers, being responsible for the excellent photocatalytic hydrogen evolution performance of the catalysts. This strategy provides new insights into the construction of efficient twin crystal heterojunctions for photocatalytic hydrogen evolution with high performance.