| 1. |
- Zhang, Zhibo, et al.
(författare)
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Encapsulation of multiple enzymes in a metal–organic framework with enhanced electro-enzymatic reduction of CO2 to methanol
- 2021
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Ingår i: Green Chemistry. - : Royal Society of Chemistry. - 1463-9262 .- 1463-9270. ; 23:6, s. 2362-2371
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Tidskriftsartikel (refereegranskat)abstract
- Efficient enzymatic conversion of CO2 to methanol is limited by low CO2 solubility in water (33 mM), and the high-cost of the cofactor (NADH) hinders the potential large-scale application of CO2 enzymatic conversion. In this study, a bioelectrocatalytic system was established for tackling both these issues, and in this system enzymes were embedded in the metal–organic framework ZIF-8 via in situ encapsulation to increase the substrate (CO2) concentration and pre-concentrate NADH, and a Rh complex-grafted electrode was developed for regenerating NADH in a sustainable manner. The results showed that after encapsulation of enzymes in ZIF-8, the methanol concentration increased from 0.061 to 0.320 mM (5 fold) in three hours. Furthermore, after coupling with electrocatalytic NADH regeneration, the methanol concentration further increased to 0.742 mM (12 fold) compared to a free enzyme system. Overall, methanol was produced at a rate of 822 μmol g−1 h−1.
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| 2. |
- Li, Jiajia, et al.
(författare)
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Gravity field induced composite solid electrolytes enabling enhanced Li+ transport kinetics of lithium metal battery
- 2024
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Ingår i: Chemical Engineering Journal. - : Elsevier. - 1385-8947 .- 1873-3212. ; 484
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Tidskriftsartikel (refereegranskat)abstract
- Multilayer composite solid electrolytes (CSEs) exhibit many advantages over uniform monolayer CSEs but are hindered by high interlayer resistance and complex preparation methods. Herein, for the first time, a natural sedimentation strategy was developed to construct concentration gradient CSEs (GCSEs) for lithium-metal batteries (LMBs). This method utilizes intrinsic gravity and photopolymerization to achieve multiple functions in the monolayer, avoiding additional interlayer resistance and reducing preparation time. Owning to the concentration gradient structure, the Li+ transport on the PolyIL-rich side relies on the weak solvation of Li+ with EMIMTFSI, while the Li+ transport on the LLZTO-rich side follows the 'vehicular diffusion' mechanism with the aid of TFSI−, improving the Li+ transport and enhances the Li+ transference number, leading to the high stability to 2300 h for the Li//Li cell and stable operation at 4.3 V with 89.6 % capacity retention after 100 cycles for the assembled LMB. Moreover, compared with the monolayer uniform hybrid CSEs, the gradient structure alleviates uncoordinated thermal expansion between LLZTO and PolyIL, avoiding stress increase during cycling and battery capacity fade. This gradient strategy mitigates high interlayer resistance and offers a universal path to address the sluggish Li+ transportation in multilayer CSEs and improves compatibility between the electrolyte and electrodes in fabricating solid-state batteries.
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| 3. |
- Li, Jiajia, et al.
(författare)
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Recent Applications of Ionic Liquids in Quasi-Solid-State Lithium Metal Batteries
- 2021
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Ingår i: Green Chemical Engineering. - : Elsevier. - 2666-9528. ; 2:3, s. 253-265
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Forskningsöversikt (refereegranskat)abstract
- Quasi-solid-state lithium metal batteries are considered as one of the most promising energy storage devices, and the application of ionic liquids (ILs) as a new generation of functionalized electrolyte components in lithium metal batteries has become one of the research focuses. In this review, the very recent research work related to using IL to develop quasi-solid-state electrolytes and their influences on the performances of quasi-solid-state lithium metal batteries were surveyed and summarized, suggesting that the introduction of ILs can improve the ionic conductivity, broaden the electrochemical stability window, and enhance the electrochemical stability of selected electrolytes. Moreover, using ILs to prepare high-performance electrodes with unique microstructures and uniform distribution of fillers were also introduced. The composite quasi-solid-state electrolytes were suggested as the mainstream of electrolytes in the future due to the combination of the advantages of inorganic and polymer quasi-solid-state electrolytes, and their development challenges in high energy and high safety quasi-solid-state lithium metal batteries were also discussed.
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| 4. |
- Li, Xiaochun, et al.
(författare)
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Bidirectional associations of intellectual and social activities with cognitive function among middle-aged and elderly adults in China
- 2022
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Ingår i: Journal of Affective Disorders. - : Elsevier BV. - 0165-0327. ; 319, s. 83-89
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Tidskriftsartikel (refereegranskat)abstract
- Background: Previous studies evaluating the association between leisure activities and cognitive function produced conflicting results. Different types of leisure activities may have different effects on cognition, and very few studies have explored their bidirectional associations. Our study aimed to explore whether intellectual and social activities had bidirectional associations with cognitive function among the middle-aged and elderly adults in China. Methods: Data was derived from the China Health and Retirement Longitudinal Study. The data in this study were based on 11,549 participants aged 45 or older whose intellectual and social activities and cognitive function were assessed at baseline. Cross-lagged panel model was used to examine the temporal relationship of intellectual and social activities with cognitive function. Results: Totally, 5624 participants completed the third follow-up in 2018. The results showed that the better the cognitive function they had at baseline, the more intellectual activities they were engage in (β = 0.044, P < 0.001) and vice versa (β = 0.042, P = 0.001). Additionally, better cognitive function at baseline was significantly associated with more engagement in social activities (β = 0.028, P = 0.030); in contrast, higher engagement in social activities at baseline was not related to better cognitive function (β = −0.008, P = 0.523). Limitations: Engagement in social and intellectual activities was assessed via questionnaire. Conclusions: Our findings indicated that there was a bidirectional relationship between intellectual activities and cognitive function. However, participation in social activities did not slow down the decline in cognitive function. Participating in intellectual activities, compared to social activities, is especially beneficial for cognitive function.
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| 5. |
- Zhang, Tiankai, et al.
(författare)
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Ion-modulated radical doping of spiro-OMeTAD for more efficient and stable perovskite solar cells
- 2022
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Ingår i: Science. - : AMER ASSOC ADVANCEMENT SCIENCE. - 0036-8075 .- 1095-9203. ; 377:6605, s. 495-501
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Tidskriftsartikel (refereegranskat)abstract
- Record power conversion efficiencies (PCEs) of perovskite solar cells (PSCs) have been obtained with the organic hole transporter 2,2,7,7-tetrakis(N,N-di-p-methoxyphenyl-amine)9,9-spirobifluorene (spiro-OMeTAD). Conventional doping of spiro-OMeTAD with hygroscopic lithium salts and volatile 4-tert-butylpyridine is a time-consuming process and also leads to poor device stability. We developed a new doping strategy for spiro-OMeTAD that avoids post-oxidation by using stable organic radicals as the dopant and ionic salts as the doping modulator (referred to as ion-modulated radical doping). We achieved PCEs of >25% and much-improved device stability under harsh conditions. The radicals provide hole polarons that instantly increase the conductivity and work function (WF), and ionic salts further modulate the WF by affecting the energetics of the hole polarons. This organic semiconductor doping strategy, which decouples conductivity and WF tunability, could inspire further optimization in other optoelectronic devices.
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| 6. |
- Cao, Yuan, et al.
(författare)
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Hybrid Trusted/Untrusted Relay Based Quantum Key Distribution over Optical Backbone Networks
- 2021
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Ingår i: IEEE Journal on Selected Areas in Communications. - 0733-8716 .- 1558-0008. ; 39:9, s. 2701-2718
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Tidskriftsartikel (refereegranskat)abstract
- Quantum key distribution (QKD) has demonstrated a great potential to provide future-proofed security, especially for 5G and beyond communications. As the critical infrastructure for 5G and beyond communications, optical networks can offer a cost-effective solution to QKD deployment utilizing the existing fiber resources. In particular, measurement-device-independent QKD shows its ability to extend the secure distance with the aid of an untrusted relay. Compared to the trusted relay, the untrusted relay has obviously better security, since it does not rely on any assumption on measurement and even allows to be accessed by an eavesdropper. However, it cannot extend QKD to an arbitrary distance like the trusted relay, such that it is expected to be combined with the trusted relay for large-scale QKD deployment. In this work, we study the hybrid trusted/untrusted relay based QKD deployment over optical backbone networks and focus on cost optimization during the deployment phase. A new network architecture of hybrid trusted/untrusted relay based QKD over optical backbone networks is described, where the node structures of the trusted relay and untrusted relay are elaborated. The corresponding network, cost, and security models are formulated. To optimize the deployment cost, an integer linear programming model and a heuristic algorithm are designed. Numerical simulations verify that the cost-optimized design can significantly outperform the benchmark algorithm in terms of deployment cost and security level. Up to 25% cost saving can be achieved by deploying QKD with the hybrid trusted/untrusted relay scheme while keeping much higher security level relative to the conventional point-to-point QKD protocols that are only with the trusted relays.
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| 7. |
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| 8. |
- Cao, Yuan, et al.
(författare)
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Multi-Tenant Provisioning for Quantum Key Distribution Networks With Heuristics and Reinforcement Learning : A Comparative Study
- 2020
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Ingår i: IEEE Transactions on Network and Service Management. - : Institute of Electrical and Electronics Engineers (IEEE). - 1932-4537. ; 17:2, s. 946-957
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Tidskriftsartikel (refereegranskat)abstract
- Quantum key distribution (QKD) networks are potential to be widely deployed in the immediate future to provide long-term security for data communications. Given the high price and complexity, multi-tenancy has become a cost-effective pattern for QKD network operations. In this work, we concentrate on addressing the online multi-tenant provisioning (On-MTP) problem for QKD networks, where multiple tenant requests (TRs) arrive dynamically. On-MTP involves scheduling multiple TRs and assigning non-reusable secret keys derived from a QKD network to multiple TRs, where each TR can be regarded as a high-security-demand organization with the dedicated secret-key demand. The quantum key pools (QKPs) are constructed over QKD network infrastructure to improve management efficiency for secret keys. We model the secret-key resources for QKPs and the secret-key demands of TRs using distinct images. To realize efficient On-MTP, we perform a comparative study of heuristics and reinforcement learning (RL) based On-MTP solutions, where three heuristics (i.e., random, fit, and best-fit based On-MTP algorithms) are presented and a RL framework is introduced to realize automatic training of an On-MTP algorithm. The comparative results indicate that with sufficient training iterations the RL-based On-MTP algorithm significantly outperforms the presented heuristics in terms of tenant-request blocking probability and secret-key resource utilization.
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| 9. |
- Chen, Jiajia, et al.
(författare)
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Characterization of Longitudinal Thermal Conductivity of Graphene Film
- 2021
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Ingår i: 2021 22nd International Conference on Electronic Packaging Technology, ICEPT 2021.
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Konferensbidrag (refereegranskat)abstract
- The chase of high performance by chip manufacturers has greatly increased the power consumption of integrated circuits, which brings great challenges to the heat dissipation of electronics systems. It has also slowed down following up of the Moore's Law, and it is expected to hit the wall soon [1]. Graphene film with high in-plane thermal conductivity is one of the key materials to make it possible for electronics industry to continue to follow the Moore's Law. However, there are few studies focusing on the longitudinal thermal conductivity of graphene films. The purpose of this study is to investigate the longitudinal thermal conductivity of graphene films according to ASTM D5470 [2]. The results show that the longitudinal thermal conductivity of the pressed graphene film is greater than that of the unpressurized graphene film. The longitudinal thermal conductivity is 10.6 W/m· K for the unpressurized graphene film and 20.6 W/m· K for the pressed graphene film.
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| 10. |
- Deng, Xuefan, et al.
(författare)
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A new strategy for boron cluster-based metal boride (Co2B) synthesis and its applicability to electrocatalytic nitrate reduction
- 2024
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Ingår i: Chemical Engineering Journal. - : ELSEVIER SCIENCE SA. - 1385-8947 .- 1873-3212. ; 485
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Tidskriftsartikel (refereegranskat)abstract
- To achieve efficient conversion of nitrate to ammonia, it is necessary to design and develop electrode materials with high activity and efficiency for the electrocatalytic reduction reaction of nitrate (NO3RR). Due to its unique semi-metallic properties, the vacancy orbitals of boron are prone to accommodate electrons, so doping element B with transition metals is expected to change the local electronic configuration of the metal, which in turn affects the corresponding catalytic reaction. Here, we propose a new strategy for the preparation of metal borides by using dodecahydro-closo-dodecaborate and Co2+ complexed and calcined to prepare a novel metal boride-Co2B for electrocatalytic nitrate reduction. This modification considerably enhances the performance of NO3RR. Co2B exhibited a Faradaic efficiency of NH4+ (FENH4+) as high as 96.61 % at -0.5 V vs. RHE, achieving a remarkable NH4+ yield of 5.73 mg h-1 mgcat - 1. This study provides a new approach for designing catalysts for environmentallyfriendly ammonia synthesis.
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