A credibility-aware swarm-federated deep learning framework in internet of vehicles

Although Federated Deep Learning(FDL)enables distributed machine learning in the Internet of Vehicles(IoV),it requires multiple clients to upload model parameters,thus still existing unavoidable communication overhead and data privacy risks.The recently proposed Swarm Learning(SL)provides a decentralized machine learning approach for unit edge computing and blockchain-based coordination.A Swarm-Federated Deep Learning framework in the IoV system(IoV-SFDL)that integrates SL into the FDL framework is proposed in this paper.The IoV-SFDL organizes vehicles to generate local SL models with adjacent vehicles based on the blockchain empowered SL,then aggregates the global FDL model among different SL groups with a credibility weights prediction algorithm.Extensive experimental results show that compared with the baseline frameworks,the proposed IoV-SFDL framework reduces the overhead of client-to-server communication by 16.72%,while the model performance improves by about 5.02%for the same training iterations.

Force-induced Caspase-1-dependent pyroptosis regulates orthodontic tooth movement

Pyroptosis,an inflammatory caspase-dependent programmed cell death,plays a vital role in maintaining tissue homeostasis and activating inflammatory responses.Orthodontic tooth movement(OTM)is an aseptic force-induced inflammatory bone remodeling process mediated by the activation of periodontal ligament(PDL)progenitor cells.However,whether and how force induces PDL progenitor cell pyroptosis,thereby influencing OTM and alveolar bone remodeling remains unknown.In this study,we found that mechanical force induced the expression of pyroptosis-related markers in rat OTM and alveolar bone remodeling process.Blocking or enhancing pyroptosis level could suppress or promote OTM and alveolar bone remodeling respectively.Using Caspase-1^(−/−)mice,we further demonstrated that the functional role of the force-induced pyroptosis in PDL progenitor cells depended on Caspase-1.Moreover,mechanical force could also induce pyroptosis in human ex-vivo force-treated PDL progenitor cells and in compressive force-loaded PDL progenitor cells in vitro,which influenced osteoclastogenesis.Mechanistically,transient receptor potential subfamily V member 4 signaling was involved in force-induced Caspase-1-dependent pyroptosis in PDL progenitor cells.Overall,this study suggested a novel mechanism contributing to the modulation of osteoclastogenesis and alveolar bone remodeling under mechanical stimuli,indicating a promising approach to accelerate OTM by targeting Caspase-1.

Prim-O-glucosylcimifugin ameliorates aging-impaired endogenous tendon regeneration by rejuvenating senescent tendon stem/progenitor cells

Adult tendon stem/progenitor cells(TSPCs)are essential for tendon maintenance,regeneration,and repair,yet they become susceptible to senescence with age,impairing the self-healing capacity of tendons.In this study,we employ a recently developed deep-learning-based efficacy prediction system to screen potential stemness-promoting and senescence-inhibiting drugs from natural products using the transcriptional signatures of stemness.The top-ranked candidate,prim-O-glucosylcimifugin(POG),a saposhnikovia root extract,could ameliorate TPSC senescent phenotypes caused by long-term passage and natural aging in rats and humans,as well as restore the self-renewal and proliferative capacities and tenogenic potential of aged TSPCs.In vivo,the systematic administration of POG or the local delivery of POG nanoparticles functionally rescued endogenous tendon regeneration and repair in aged rats to levels similar to those of normal animals.Mechanistically,POG protects TSPCs against functional impairment during both passage-induced and natural aging by simultaneously suppressing nuclear factor-κB and decreasing mTOR signaling with the induction of autophagy.Thus,the strategy of pharmacological intervention with the deep learning-predicted compound POG could rejuvenate aged TSPCs and improve the regenerative capacity of aged tendons.

Ag(111)表面Ag配位结构的分等级组装

表面辅助的金属有机纳米结构因其结构稳定性和潜在应用受到广泛关注。在金属有机纳米结构中,金属原子来源于外部沉积的金属或金属表面原子。外部沉积的金属原子种类多样,取决于目标纳米结构。然而,金属表面原子受限于表面科学常用的金、银和铜单晶金属表面。金属有机纳米结构大多包括Au配位或是Cu配位结构,而只有少量的用表面Ag原子构成。分子金属相互作用的进一步研究有助于预期纳米结构的精确控制形成。至于构建基元,有机分子通过M―C、M―N和M―O键与表面金属原子配位。末端炔反应或者乌尔曼耦合能够实现C―M―C节点的形成。Cu和Au原子能够与含有末端氰基或吡啶基官能团的分子配位形成N―M―N键。另外,表面Ag增原子能够通过Ag―N配位键与酞菁分子配位。然而,M―O配位键的相关研究较少。因此,我们计划使用末端羟基分子与Ag增原子配位形成金属有机配位纳米结构去研究O―Ag节点。我们通过扫描隧道显微镜利用4,4’-二羟基-1,1’:3’,1’’-三联苯分子(4,4’-dihydroxy-1,1’:3’,1’’-terphenyl,H3PH)和Ag增原子成功构筑了一系列二维有序纳米结构。在室温下,蒸镀的H3PH分子自组装形成由环氢键连接的密堆积结构。当退火温度提升到330K,一种新的纳米结构出现了,该结构由O―Ag配位键和氢键共同作用形成。进一步地提升退火温度至420K,蜂巢结构和共存的二重配位链出现,这两种结构中仅由O―Ag―O键构成。为分析金属分子反应路径和O―Ag―O键的能量势垒,我们对该体系进行密度泛函理论计算。计算结果显示,O―Ag键形成的能量势垒是1.41 eV,小于O―Ag―O节点1.85 e V的能量势垒。这也解释了分等级金属-有机纳米结构形成的原因。我们的实验结果提供了一种利用有机小分子和金属增原子来设计和构筑分等级二维纳米结构的有效方法。

The Main Progress of Perovskite Solar Cells in 2020-2021

Perovskite solar cells(PSCs)emerging as a promising photovoltaic technology with high efficiency and low manufacturing cost have attracted the attention from all over the world.Both the efficiency and stability of PSCs have increased steadily in recent years,and the research on reducing lead leakage and developing eco-friendly lead-free perovskites pushes forward the commercialization of PSCs step by step.This review summarizes the main progress of PSCs in 2020 and 2021 from the aspects of efficiency,stability,perovskite-based tandem devices,and lead-free PSCs.Moreover,a brief discussion on the development of PSC modules and its challenges toward practical application is provided.

Heterogeneous FASnI3 Absorber with Enhanced Electric Field for High-Performance Lead-Free Perovskite Solar Cells

Lead-free tin perovskite solar cells(PSCs)have undergone rapid development in recent years and are regarded as a promising ecofriendly photovoltaic technology.However,a strategy to suppress charge recombination via a built-in electric field inside a tin perovskite crystal is still lacking.In the present study,a formamidinium tin iodide(FASnI;)perovskite absorber with a vertical Sn;gradient was fabricated using a Lewis base-assisted recrystallization method to enhance the built-in electric field and minimize the bulk recombination loss inside the tin perovskites.Depth-dependent X-ray photoelectron spectroscopy revealed that the Fermi level upshifts with an increase in Sn;content from the bottom to the top in this heterogeneous FASnI;film,which generates an additional electric field to prevent the trapping of photo-induced electrons and holes.Consequently,the Sn;-gradient FASnI;absorber exhibits a promising efficiency of 13.82%for inverted tin PSCs with an open-circuit voltage increase of 130 mV,and the optimized cell maintains over 13%efficiency after continuous operation under 1-sun illumination for 1,000 h.

LEO Enhanced Global Navigation Satellite System(LeGNSS):progress,opportunities,and challenges

With the completion of Chinese BeiDou Navigation Satellite System(BDS),the world has begun to enjoy the Positioning,Navigation,and Timing(PNT)services of four Global Navigation Satellite Systems(GNSS).In order to improve the GNSS performance and expand its applications,Low Earth Orbit(LEO)Enhanced Global Navigation Satellite System(LeGNSS)is being vigorously advocated.Combined with high-,medium-,and low-earth orbit satellites,it can improve GNSS performance in terms of orbit determination,Precise Point Positioning(PPP)convergence time,etc.This paper comprehensively reviews the current status of LeGNSS,focusing on analyzing its advantages and challenges for precise orbit and clock determination,PPP convergence,earth rotation parameter estimation,and global ionosphere modeling.Thanks to the fast geometric change brought by LEO satellites,LeGNSS is expected to fundamentally solve the problem of the long convergence time of PPP without any augmentation.The convergence time can be shortened within 1 minute if appropriate LEO constellations are deployed.However,there are still some issues to overcome,such as the optimization of LEO constellation as well as the real time LEO precise orbit and clock determination.

Efficient and stable tin-based perovskite solar cells by introducing π-conjugated Lewis base

Tin-based perovskite solar cells(TPSCs)as the most promising candidate for lead-free PSCs have incurred extensive researches all over the world.However,the crystallization process of tin-based perovskite is too fast during the solution-deposited process,resulting in abundant pinholes and poor homogeneity that cause serious charge recombination in perovskite layer.Here,we employed theπ-conjugated Lewis base molecules with high electron density to systematically control the crystallization rate of FASnI3 perovskite by forming stable intermediate phase with the Sn-I frameworks,leading to a compact and uniform perovskite film with large increase in the carrier lifetime.Meanwhile,the introduction of theπ-conjugated systems also retards the permeation of moisture into perovskite crystal,which significantly suppresses the film degradation in air.These benefits contributed to a stabilizing power conversion efficiency(PCE)of 10.1%for the TPSCs and maintained over 90%of its initial PCE after 1000-h light soaking in air.Also,a steady-state efficiency of 9.2%was certified at the accredited test center.

Sn_(4)P_(3)-induced crystalline/amorphous composite structures for enhanced sodium-ion battery anodes

The optimization of anode materials such as Sn,P and Sn4P3 in terms of capacity and cyclability is crucial to improve the overall performance of sodium-ion batteries.However,the delicate fabrication of these materials,including the balanced crystalline/amorphous domains,reasonable particle size and distribution,complementary components exhibiting synergetic reactions,among others,still greatly retards the realization of maximum performance.Herein,a series of Sn/P-based composite materials with a plum pudding configuration were fabricated to achieve controlled crystalline/amorphous structures as well as optimized size and distribution in a carbon framework.By using a facile and low-cost ball milling method,the structural transformation of Sn4P3 into phase-separated crystalline Sn and amorphous P in a carbonaceous framework can be finely controlled,producing a series of binary(Sn4 P3/C),quaternary(Sn4P3/Sn/P/C) and ternary(Sn/P/C) composites.Due to the complementary components,crystalline/amorphous adjustment,crystallite sizes and well-integrated interfaces,the quaternary Sn4P3/Sn/P/C composite showed the best electrochemical performance,with a noticeable long-cycle performance of 382 mA hg-1 and 86% capacity retention for nearly 300 cycles.Different from binary and ternary composites,the discharge of quaternary composite generates no noticeable signals of Na15Sn4 and Na3 P in the ex-situ X-ray diffraction patterns,suggesting the crystallite growth of sodiation products can be depressed.Moreover,Sn4 P3 in the quaternary composite can be partially regenerated in the desodiation reaction,implying the significant short-range interaction and thus better synergetic reactions between Sn and P components.The results demonstrate that the design and organization of crystalline/amorphous structures can serve as an efficient strategy to develop novel electrode materials for sodium ion batteries.

Progress of all-perovskite tandem solar cells:the role of narrow-bandgap absorbers

Perovskite solar cells(PSCs)have gained increasing attention due to their excellent photovoltaic performance,achieving certified power conversion efficiency(PCE)of 25.2%.To further enhance PCE and break the Shockley-Queisser limit of the single junction PSCs,great efforts have been made in tandem solar cells based on perovskite,including perovskite/Si,and perovskite/perovskite(all-perovskite).Among them,all-perovskite tandem solar cells exhibit unique advantages of both lowcost fabrication and high efficiency.They have advanced rapidly in these years,due to the realization of stable and efficient narrow-bandgap perovskites.In this work,we review the development of monolithic all-perovskite tandem solar cells and highlight the critical role of narrow-bandgap perovskites in recent progress of all-perovskite solar cells.We also propose our perspective of future directions on this subject.

Atomic pair distribution function research on Li_2MnO_3 electrode structure evolution

The mechanism research of structure-related reactions on Li_2MnO_3 is important to enhance the electrochemical performance of lithium-manganese-rich layered oxides.Although there are some reports on the structure evolution of Li_2MnO_3 during cycling process,the employed research techniques are very limited,mainly in/ex-situ X-ray diffraction,X-ray absorption and transmission electron microscopy.Here,atomic pair distribution function,a method to study the local atomic arrangement on the basis of average spectroscopic information,is used for the first time to study the local structure evolution of Li_2MnO_3 during electrochemical charge/discharge cycles.The results clearly demonstrate that Mn^(3+)/Mn^(4+) redox couple is activated and Mn ions are reduced during discharging process.Some Mn ions in Mn layers can significantly migrate to Li layers and occupy the octahedral sites.As a result,a portion of inserted Li ions can occupy the face-shared tetrahedron sites,accompanied by the formation of local spinel-like structure.This work provides an important and suitable method based on the average spectroscopic information to investigate the local structure of electrode materials of lithium-ion batteries as well as other advanced battery systems.

Knowledge graph quality control:A survey

A knowledge graph(KG),a special form of semantic network,integrates fragmentary data into a graph to support knowledge processing and reasoning.KG quality control is important to the utility of KGs.It is essential to investigate KG quality and the parameters influencing KG quality to better understand its quality control.Although many works have been conducted to evaluate the dimensions of KG quality,quality control of the construction process,and enhancement methods for quality,a comprehensive literature review has not been presented on this topic.This paper intends to fill this research gap by presenting a comprehensive survey on the quality control of KGs.First,this paper defines six main evaluation dimensions of KG quality and investigates their correlations and differences.Second,quality control treatments during KG construction are introduced from the perspective of these dimensions of KG quality.Third,the quality enhancement of a constructed KG is described from various dimensions.This paper ultimately aims to promote the research and applications of KGs.

表面非周期有序结构的扫描隧道显微镜研究

基于分子自组装的分形、准晶等非周期有序结构的表面制备在近年来取得了一系列进展.本文综述了基于扫描隧道显微镜对表面谢尔宾斯基三角分形结构和准晶结构的研究.通过改变前驱体类型,可在不同基底上分别实现基于卤键、氢键、配位键、共价键的谢尔宾斯基三角分形结构的制备,并结合模板法和共组装法,突破生长动力学的限制,使得分形结构的级数达到五级.利用羧基间的氢键作用,可通过分子自组装构建表面分子准晶结构,并通过有机分子与稀土原子间的配位作用,成功实现金属有机配位准晶的制备.

Room-temperature reduction of NO2 in a Li-NO2 battery: a proof of concept

Although considerable effort has been devoted to purifying nitrogen oxides(NOx),it is still challenging to effectively reduce NOxat room temperature and ambient pressure without catalysts.In this study,as a proof-of-concept,we have for the first time demonstrated the room-temperature reduction of nitrogen dioxide(NO2)using a rechargeable lithium-nitrogen dioxide(Li-NO2)battery.The battery shows a capacity of 884 m Ah g-1 at 50 m A g-1(an actual energy density of 666 Wh kg-1)and a promising electrochemical Faraday efficiency(FE)of 67%.The unique properties of Li-NO2 rechargeable batteries not only provide a way to reduce and recycle NO2 but also highlight the potential of oxidative air pollutants as energy sources for next-generation electrochemical energy storage(EES)systems.