| 1. |
|
|
| 2. |
- Li, Ruiyun, et al.
(författare)
-
Operando Formation of Van der Waals Heterostructures for Achieving Macroscale Superlubricity on Engineering Rough and Worn Surfaces
- 2022
-
Ingår i: Advanced Functional Materials. - : John Wiley & Sons. - 1616-301X .- 1616-3028. ; 32:18
-
Tidskriftsartikel (refereegranskat)abstract
- Macroscale superlubricity breakdown of lubricating materials caused by substrate surface roughening and mechanochemical modification poses great challenges for their practical tribological applications. Here, a facile way is reported to access robust macroscale superlubricity in a vacuum environment, via the operando formation of graphene/transition-metal dichalcogenide (TMDC) heterostructures at wear-induced rough surfaces. By trapping active amorphous carbon (a-C) wear products between TMDC flakes, the sandwich structures readily transform into graphene/TMDC heterostructures during running-in stage, based on shear-induced confinement and load-driven graphitization effects. Then they assemble into multipoint flake-like tribofilms to achieve macroscale superlubricity at steady stage by reducing contact area, eliminating strong cross-interface carbon–carbon interactions and polishing a-C rough nascent surface. Atomistic simulations reveal the preferential formation of graphene/TMDC heterostructures during running-in stage and demonstrate the superlubric sliding of TMDCs on the graphene. The findings are of importance to achieve robust superlubricity and provide a good strategy for the synthesis of other van der Waals heterostructures.
|
|
| 3. |
- Zhang, Qing, et al.
(författare)
-
Andersson-Magnéli Phases TinO2n-1 : Recent Progress Inspired by Swedish Scientists
- 2021
-
Ingår i: Zeitschrift für Anorganische und Allgemeines Chemie. - : Wiley. - 0044-2313 .- 1521-3749. ; 647:2-3, s. 126-133
-
Tidskriftsartikel (refereegranskat)abstract
- Among homologous series of metal oxides, Andersson-Magneli phases TinO2n-1 (n=4-10) have attracted renewed scientific attention because of their behaviour in electrical conductivity and chemical/thermal stability. Various applications have also been reported for the phases with different values of n, or slightly reduced rutile (TiO2). The characteristic properties of these materials depend strongly on the compositional deviation from TiO2 and the way in which the structure accommodates the deviation. Thus, an urgent requirement is to overcome difficulties in characterizing such materials at atomic resolution. Here, we trace the discovery of the Andersson-Magneli phases, and report the application of recent developments in electron microscopy to reveal the relation, at the local level, between structural characteristics and electronic states, specifically for the materials TinO2n-1 with n=4-8. The electrical conductivity of Ti4O7 has been reported previously to show three clearly distinct states on decreasing temperature from 300 K. For this reason, we focus on Ti4O7 as a representative example of the TinO2n-1 phases and report structural characteristics at temperatures corresponding to each of the three different phases, focusing on the distribution of Ti3+ and Ti4+ cations from analysis of single-crystal XRD data. Electron diffraction experiments and electrical conductivity measurements are also reported.
|
|
| 4. |
- Donkervliet, Jesse, et al.
(författare)
-
Servo : Increasing the Scalability of Modifiable Virtual Environments Using Serverless Computing
- 2023
-
Ingår i: 2023 IEEE 43RD INTERNATIONAL CONFERENCE ON DISTRIBUTED COMPUTING SYSTEMS, ICDCS. - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 829-840
-
Konferensbidrag (refereegranskat)abstract
- Online games with modifiable virtual environments (MVEs) have become highly popular over the past decade. Among them, Minecraft-supporting hundreds of millions of users-is the best-selling game of all time, and is increasingly offered as a service. Although Minecraft is architected as a distributed system, in production it achieves this scale by partitioning small groups of players over isolated game instances. From the approaches that can help other kinds of virtual worlds scale, none is designed to scale MVEs, which pose a unique challenge-a mix between the count and complexity of active in-game constructs, player-created in-game programs, and strict quality of service. Serverless computing emerged recently and focuses, among others, on service scalability. Thus, addressing this challenge, in this work we explore using serverless computing to improve MVE scalability. To this end, we design, prototype, and evaluate experimentally Servo, a serverless backend architecture for MVEs. We implement Servo as a prototype and evaluate it using real-world experiments on two commercial serverless platforms, of Amazon Web Services (AWS) and Microsoft Azure. Results offer strong support that our serverless MVE can significantly increase the number of supported players per instance without performance degradation, in our key experiment by 40 to 140 players per instance, which is a significant improvement over state-of-the-art commercial and open-source alternatives. We release Servo as open-source, on Github: https://github.com/atlarge-research/opencraft.
|
|
| 5. |
|
|
| 6. |
- Yin, Lihua, et al.
(författare)
-
A game-theoretic approach to advertisement dissemination in ephemeral networks
- 2018
-
Ingår i: World wide web (Bussum). - : Springer. - 1386-145X .- 1573-1413. ; 21:2, s. 241-260
-
Tidskriftsartikel (refereegranskat)abstract
- In ephemeral networks, disseminating advertisements faces two dilemmatic problems: on the one hand, disseminators own the limited resources and have privacy concerns, thus, often preferring to avoid disseminating advertisements without enough incentives; Even if advertisements are disseminated, their dissemination accuracy is lower. On the other hand, false advertisements may flood in ephemeral networks if too many incentives but no punishments are given. Thus, it is a challenge to design an effective scheme to guarantee rational disseminators have sufficient impetus to forward true advertisements to the interested consumers and report false advertisements, despite facing the limitation of resources and the risk of privacy leakage. To solve this problem, in this paper, a bargaining-based scheme is proposed to motive disseminators to forward the true advertisements to the interested node and a semi-grim policy is designed for punishing the disseminators who releases and disseminates false advertisements. Acknowledging the assumption of incomplete information, a repeated dissemination game is proposed to help disseminators to decide whether to forward advertisements or report false advertisements. Simulation results demonstrate that our scheme not only provides disseminators a strong impetus to disseminate the advertisements with higher dissemination accuracy, but also effectively prevents disseminators from forwarding false advertisements.
|
|
| 7. |
- Zhang, Qing, et al.
(författare)
-
Electron Microscopy Studies of Local Structural Modulations in Zeolite Crystals
- 2020
-
Ingår i: Angewandte Chemie. - : Wiley. - 0044-8249 .- 1521-3757. ; 132:44, s. 19571-19581
-
Forskningsöversikt (refereegranskat)abstract
- Zeolites are widely used in catalysis, gas separation, ion exchange, etc. due to their superior physicochemical properties, which are closely related to specific features of their framework structures. Although more than two hundred different framework types have been recognized, it is of great interest to explore from a crystallographic perspective, the atomic positions, surface terminations, pore connectivity and structural defects that deviate from the ideal framework structures, namely local structural modulation. In this article, we review different types of local modulations in zeolite frameworks using various techniques, especially electron microscopy (EM). The most recent advances in resolving structural information at the atomic level with aberration corrected EM are also presented, commencing a new era of gaining atomic structural information, not only for all tetrahedral atoms including point vacancies in framework but also for extra-framework cations and surface terminations.
|
|
