N-doping has significant influence in manipulating the properties of TiO_(2),and this has stimulated the development of N-donor-functionalized titanium-oxo clusters(TOCs)as molecular models to study the structure-prop...N-doping has significant influence in manipulating the properties of TiO_(2),and this has stimulated the development of N-donor-functionalized titanium-oxo clusters(TOCs)as molecular models to study the structure-property relationship.However,the structural type and photoresponsive application are still limited for such TOCs,especially regarding the high-nuclearity TOCs that contain structure unit of TiO_(2)for photocatalysis.Herein,we showed the synthesis of a series of high-nuclearity TOCs 1-3 compounds usingπ-conjugated 1,10-phenanthroline(phen)as chromophore and N-donor functional ligand.Compound 1 features cocrystal structure composed of one[Ti_(26)]~(2+)and half[Ti_(22)]~(2+),which renders it as the first cocrystallized TOC containing two positively charged species and phen-functionalized TOC showing the highest nuclearity up to 37 Ti centers.By adjusting the synthetic conditions,the individual{Ti_(22)}and{Ti_(26)}clusters can also be isolated as Compounds 2 and 3,respectively.The core structure of{Ti_(22)}is mainly constructed from four lacunary{Ti_(4)}derived from pentagonal{Ti(Ti)_5}unit,while{Ti_(26)}is built from four complete{Ti(Ti)_5}unit.Notably,a{Ti_8O_(14)}structure unit of anatase TiO_(2)can be identified in{Ti_(26)}.Based on the unique structural features and proper photophysical and photochemical properties of Compounds 1-3,they are applied for photocatalytic sulfoxidation.Owing to the presence of anatase structure unit in{Ti_(26)}and the synergistic effect from{Ti_(22)}and{Ti_(26)},the catalytic performance presents in the order of Compound 1>Compound 3>Compound 2.This work provides excellent models to understand the structureproperty relationship from the perspective of cocrystallization and Ti-O binding model and will further promote the application of TOCs as functional catalysts for organic transformation.展开更多
Photoactive functionalized titanium-oxo clusters(TOCs)are regarded as an important model compound for dye-sensitized titanium dioxide solar cells.However,the dyes used for sensitizing TOCs are still limited.Herein,two...Photoactive functionalized titanium-oxo clusters(TOCs)are regarded as an important model compound for dye-sensitized titanium dioxide solar cells.However,the dyes used for sensitizing TOCs are still limited.Herein,two cyclic TOCs are reported,namely,[Ti_(6)(μ_(3)-O)_(2)(Oi-Pr)_(8))(LA)_(2)]·i-PrOH(S1)and[Ti_(6)(μ_(3)-O)2(Oi-Pr)_(8))(LV)_(2)]·i-PrOH(S2),which are functionalized by photoactive naphthalene diimide(NDI)chromophores.Their molecular structures and photophysical and photochemical properties were systematically studied.As shown by ultraviolet-visible(UV-vis)spectra and photocurrent study results,the band gap and the photocurrent response of S1 and S2 were derived from NDI ligands which extend the absorption edge of S1 and S2 approaching 500 nm and afford high photocurrent densities of 2.12μA/cm^(2)and 1.95μA/cm^(2)for S1 and S2,respectively,demonstrating the significance of the photoactive ligand in modulating photoresponse of TOCs.This work is expected to enrich the structural library of photoactive TOCs and provide insights into understanding the structure-property relationships of sensitized clusters.展开更多
Supramolecular transformations of coordination cage or capsule have received much attention recently,which help elucidate this natural self-assembly behavior in biological systems.The current study describes the first...Supramolecular transformations of coordination cage or capsule have received much attention recently,which help elucidate this natural self-assembly behavior in biological systems.The current study describes the first supramolecular transformation of titanium-o rganic coordination capsule triggered by phenol(and H_(3) PO_(3)).The structural alterations are accompanied by the reconstruction of 5-coordinated Ti centers to 6-coordinated ones.Meanwhile,different amounts of encapsulated phenol vip molecules can be identified,dependent on the sizes of the obtained cavities.In addition,they display much better visible light absorption and air stability than the isopropanol stabilized ones.展开更多
The synthesis of titanium oxo clusters(TOCs)with both chirality and photoactivity is urgently needed to expand their applications.However,this remains a significant challenge due to synthetic difficulties and limitati...The synthesis of titanium oxo clusters(TOCs)with both chirality and photoactivity is urgently needed to expand their applications.However,this remains a significant challenge due to synthetic difficulties and limitations in chiral ligand selection.In this work,we have isolated two pairs of enantiomeric TOCs,[Ti_(3)(μ_(3)-O)(R/S-L1)_(2)(^(i)PrO)_(6)](R/S-Ti_(3);^(i)PrOH=isopropanol,R/S-L1=R/S-2'-hydroxy-[1,1'-binaphthalen]-2-yl isopropyl hydrogenphosphate)and[Ti_(4)(μ_(2)-O)(μ_(4)-O)(R/S-L2)_(2)(EtO)_(8)](R/S-Ti4;EtOH=ethanol,R/S-L2=R/S-2'-hydroxy-[1,1'-binaphthalen]-2-yl ethyl hydrogenphosphate),via an in situ ligand transformation approach.The R/S-L1 and R/S-L2 ligands were obtained by alcoholysis of R/S-L(R/S-1,1'-binaphthyl-2,2'-diyl hydrogenphosphate)in different reaction solvents.These ligands,with additional coordination sites,facilitated the formation of novel TOCs and improved their stability.Importantly,these clusters exhibited exceptional stability in solid state and maintained appreciable stability in solution.Furthermore,the introduction of chiral ligands not only imparts a homochiral nature to R/S-Ti3 and R/S-Ti4 but also confers upon them superior photoelectric properties due to ligand-to-metal charge transfer(LMCT)phenomena,as confirmed by theoretical calculations.This study offers a valuable synthetic strategy for preparing photoactive chiral TOCs,and we anticipate it will inspire new discoveries in the field of chiral metal nanoclusters.展开更多
Titanium-based materials have emerged as promising candidates for photo-Fenton-like catalysis,whereas their structural complexities impede precise understanding of the relevant structure–activity relationships.Owing ...Titanium-based materials have emerged as promising candidates for photo-Fenton-like catalysis,whereas their structural complexities impede precise understanding of the relevant structure–activity relationships.Owing to their well-defined and tunable structures,titaniumoxo clusters appear to be facile models for looking into the photophysical and photochemical processes in Ti-H_(2)O_(2) systems.Using PTC-3 as a prototype,we interrogated the relationship between Ti-site coordination environments and photo-Fenton-like behaviors.Through integrated in-situ/exsitu spectroscopic analyses and theoretical simulations,we elucidated light-driven H_(2)O_(2) activation on hexa-coordinated and penta-coordinated Ti sites in PTC-3.The superiority of penta-coordinated Ti site was identified,where extended visible-light absorption and promoted electron transfer could synergistically boost the activation of H_(2)O_(2) into superoxide radicals.This work brightens the role of Ti-site coordination geometry in photo-Fenton-like processes and paves the way for pursuing titanium-based advanced oxidation.展开更多
Molecular solid solutions of metal clusters containing different metal centers with well-defined structures can accurately regulate the HOMO-LUMO gap,but are rarely available.Herein,a series of colorless lanthanide-ti...Molecular solid solutions of metal clusters containing different metal centers with well-defined structures can accurately regulate the HOMO-LUMO gap,but are rarely available.Herein,a series of colorless lanthanide-titanium-oxo clusters Ln_(2)Ti_4(μ_(2)-O)_(2)(μ_(3)-O)_4(Piv)_(10)(THF)_(2)(Ln_(2)Ti_4,Ln = Eu,Gd,Tb,and Ce,HPiv = pivalic acid) were synthesized by the reaction of pivalic acid with Ln(Ac)_(3) and titanium isopropoxide.The light yellow crystal of cluster solid solutions Eu_(2)Ti_(4-x)Cd_(x),containing a mixture of Eu_(2)Ti_4 and Eu_(2)Ti_(3)Cd,was obtained by in situ doping Cd^(2+) and S^(2–).Eu_(2)Ti_(3.92)Cd_(0.08) displays efficient photocatalytic hydrogen evolution activity without a co-catalyst,which is up to 2.6 times that of Eu_(2)Ti_4.Femtosecond time-resolved transient absorption spectroscopy and spin-polarized density functional calculations showed that the enhanced photocatalytic performance of Eu_(2)Ti_(4-x)Cd_(x) can be attributed to the narrower HOMO-LUMO gap and lower LUMO position than that of Eu_(2)Ti_4.This studyprovides an in situ doping method to realize the simple preparation of cluster solid solution.展开更多
Compared with nanoparticle-aspect relatives titanium dioxide(TiO2),titanium-oxo clusters(TOCs)are atomically structural-determined and can be further precisely modified through coordination and supramolecular chemistr...Compared with nanoparticle-aspect relatives titanium dioxide(TiO2),titanium-oxo clusters(TOCs)are atomically structural-determined and can be further precisely modified through coordination and supramolecular chemistry.Another parallel research direction is titanium-based metal-organic frameworks,and those based on TOC have attracted particular attention because of their high optical performances resulting from the cluster aggregation effect.Though challenging,assembling macro-materials from specific clusters helps establish the assembly chemistry of clusters and incorporates porous andflexible characteristics into a single bulk material.Although separate reviews are reported in these two branches,no com-prehensive review is available to highlight the bridges between them.Herein,we review and summarize the development and progress of new aggregation of TOCs,from intramolecular unique cluster aggregation to hierarchical intermolecular aggre-gation via covalent forces,coordination bonds,and non-covalent forces using the specific clusters as precursors.We hope this reviewfills the gap in the methodology of assembling particular-aggregated TOCs and their derived frameworks,providing general guidance to researchers interested in this area.展开更多
Subject Code:B01 Photocatalytic hydrogen evolution by water-splitting has been recognized as one of the most promising solutions to the global energy and environment crisis,owing to its renewable solar energy source a...Subject Code:B01 Photocatalytic hydrogen evolution by water-splitting has been recognized as one of the most promising solutions to the global energy and environment crisis,owing to its renewable solar energy source and clean chemical fuel product.Cadmium sulfide(CdS)and TiO2(or related polyoxo-titanium clusters)are two展开更多
Perovskite and organic solar cells usually require electron-transport interlayers to efficiently transport electrons from the photoactive layer to the metal electrode.In general,pure organic or inorganic materials are...Perovskite and organic solar cells usually require electron-transport interlayers to efficiently transport electrons from the photoactive layer to the metal electrode.In general,pure organic or inorganic materials are applied into the interlayers,but organic–inorganic hybrid materials have been rarely reported for this application.In this work,we report using the first titanium-oxo cluster-based organic–inorganic hybrid as the interlayer material by introducing largeπ-conjugated benzo[ghi]perylenetriimides as an organic part via a simple ligand-exchange reaction.This new hybrid material showed excellent solubility,well-aligned energy levels,and excellent electron mobilities,enabling its great potential application as an interlayer in solar cells such as perovskite and organic solar cells,providing high power conversion efficiencies of>20%and 16%,respectively.Therefore,we claim that our present work introduces a new class of cluster-based organic–inorganic hybrid interlayer materials that exhibit promising application in organic electronics.展开更多
Federated learning is a machine learning framework designed to protect privacy by keeping training data on clients’devices without sharing private data.It trains a global model through collaboration between clients a...Federated learning is a machine learning framework designed to protect privacy by keeping training data on clients’devices without sharing private data.It trains a global model through collaboration between clients and the server.However,the presence of data heterogeneity can lead to inefficient model training and even reduce the final model’s accuracy and generalization capability.Meanwhile,data scarcity can result in suboptimal cluster distributions for few-shot clients in centralized clustering tasks,and standalone personalization tasks may cause severe overfitting issues.To address these limitations,we introduce a federated learning dual optimization model based on clustering and personalization strategy(FedCPS).FedCPS adopts a decentralized approach,where clients identify their cluster membership locally without relying on a centralized clustering algorithm.Building on this,FedCPS introduces personalized training tasks locally,adding a regularization term to control deviations between local and cluster models.This improves the generalization ability of the final model while mitigating overfitting.The use of weight-sharing techniques also reduces the computational cost of central machines.Experimental results on MNIST,FMNIST,CIFAR10,and CIFAR100 datasets demonstrate that our method achieves better personalization effects compared to other personalized federated learning methods,with an average test accuracy improvement of 0.81%–2.96%.Meanwhile,we adjusted the proportion of few-shot clients to evaluate the impact on accuracy across different methods.The experiments show that FedCPS reduces accuracy by only 0.2%–3.7%,compared to 2.1%–10%for existing methods.Our method demonstrates its advantages across diverse data environments.展开更多
Many fields,such as neuroscience,are experiencing the vast prolife ration of cellular data,underscoring the need fo r organizing and interpreting large datasets.A popular approach partitions data into manageable subse...Many fields,such as neuroscience,are experiencing the vast prolife ration of cellular data,underscoring the need fo r organizing and interpreting large datasets.A popular approach partitions data into manageable subsets via hierarchical clustering,but objective methods to determine the appropriate classification granularity are missing.We recently introduced a technique to systematically identify when to stop subdividing clusters based on the fundamental principle that cells must differ more between than within clusters.Here we present the corresponding protocol to classify cellular datasets by combining datadriven unsupervised hierarchical clustering with statistical testing.These general-purpose functions are applicable to any cellular dataset that can be organized as two-dimensional matrices of numerical values,including molecula r,physiological,and anatomical datasets.We demonstrate the protocol using cellular data from the Janelia MouseLight project to chara cterize morphological aspects of neurons.展开更多
The pursuit of Ag-based alloys with both high strength and toughness has posed a longstanding chal-lenge.In this study,we investigated the cluster strengthening and grain refinement toughening mecha-nisms in fully oxi...The pursuit of Ag-based alloys with both high strength and toughness has posed a longstanding chal-lenge.In this study,we investigated the cluster strengthening and grain refinement toughening mecha-nisms in fully oxidized AgMgNi alloys,which were internally oxidized at 800℃ for 8 h under an oxy-gen atmosphere.We found that Mg-O clusters contributed to the hardening(138 HV)and strengthening(376.9 MPa)of the AgMg alloy through solid solution strengthening effects,albeit at the expense of duc-tility.To address this limitation,we introduced Ni nanoparticles into the AgMg alloy,resulting in signifi-cant grain refinement within its microstructure.Specifically,the grain size decreased from 67.2μm in the oxidized AgMg alloy to below 6.0μm in the oxidized AgMgNi alloy containing 0.3 wt%Ni.Consequently,the toughness increased significantly,rising from toughness value of 2177.9 MJ m^(-3) in the oxidized AgMg alloy to 6186.1 MJ m^(-3) in the oxidized AgMgNi alloy,representing a remarkable 2.8-fold enhancement.Furthermore,the internally oxidized AgMgNi alloy attained a strength of up to 387.6 MPa,comparable to that of the internally oxidized AgMg alloy,thereby demonstrating the successful realization of concurrent strengthening and toughening.These results collectively offer a novel approach for the design of high-performance alloys through the synergistic combination of cluster strengthening and grain refinement toughening.展开更多
By systematically reviewing the development status of global carbon dioxide capture,utilization and storage(CCUS)cluster,and comparing domestic and international CCUS industrial models and successful experiences,this ...By systematically reviewing the development status of global carbon dioxide capture,utilization and storage(CCUS)cluster,and comparing domestic and international CCUS industrial models and successful experiences,this study explores the challenges and strategies for the scaled development of the CCUS industry of China.Globally,the CCUS industry has entered a phase of scaled and clustered development.North America has established a system of key technologies in large-scale CO_(2) capture,long-distance pipeline transmission,pipeline network optimization,and large-scale CO_(2) flooding for enhanced oil recovery(CO_(2)-EOR),with relatively mature cluster development and a gradual shift in industrial model from CO_(2)-EOR to geological storage.The CCUS industry of China has developed rapidly across all segments but remains in the early stage of cluster development,facing challenges such as absent business model,insufficient policy support,and technological gaps in core areas.China needs to improve the policy support system to boost enterprises participation across the entire industrial chain,strengthen top-level design and medium-to long-term planning to accelerate demonstration projects construction for whole-process CCUS clusters,advance for a full-chain technological system,including low-cost capture,pipeline optimization and EOR/storage integration technologies,and strengthen personnel training,strengthen discipline construction and university-enterprise research cooperation.展开更多
Thermally activated delayed fluorescence(TADF)materials driven by a through-space charge transfer(TSCT)mechanism have garnered wide interest.However,access of TSCT-TADF molecules with longwavelength emission remains a...Thermally activated delayed fluorescence(TADF)materials driven by a through-space charge transfer(TSCT)mechanism have garnered wide interest.However,access of TSCT-TADF molecules with longwavelength emission remains a formidable challenge.In this study,we introduce a novel V-type DA-D-A’emitter,Trz-mCzCbCz,by using a carborane scaffold.This design strategically incorporates carbazole(Cz)and 2,4,6-triphenyl-1,3,5-triazine(Trz)as donor and acceptor moieties,respectively.Theoretical calculations alongside experimental validations affirm the typical TSCT-TADF characteristics of this luminogen.Owing to the unique structural and electronic attributes of carboranes,Trz-mCzCbCz exhibits an orange-red emission,markedly diverging from the traditional blue-to-green emissions observed in classical Cz and Trz-based TADF molecules.Moreover,bright emission in aggregates was observed for Trz-mCzCbCz with absolute photoluminescence quantum yield(PLQY)of up to 88.8%.As such,we have successfully fabricated five organic light-emitting diodes(OLEDs)by utilizing Trz-mCzCbCz as the emitting layer.It is important to note that both the reverse intersystem crossing process and the TADF properties are profoundly influenced by host materials.The fabricated OLED devices reached a maximum external quantum efficiency(EQE)of 12.7%,with an emission peak at 592 nm.This represents the highest recorded efficiency for TSCT-TADF OLEDs employing carborane derivatives as emitting layers.展开更多
For multi-vehicle networks,Cooperative Positioning(CP)technique has become a promising way to enhance vehicle positioning accuracy.Especially,the CP performance could be further improved by introducing Sensor-Rich Veh...For multi-vehicle networks,Cooperative Positioning(CP)technique has become a promising way to enhance vehicle positioning accuracy.Especially,the CP performance could be further improved by introducing Sensor-Rich Vehicles(SRVs)into CP networks,which is called SRV-aided CP.However,the CP system may split into several sub-clusters that cannot be connected with each other in dense urban environments,in which the sub-clusters with few SRVs will suffer from degradation of CP performance.Since Unmanned Aerial Vehicles(UAVs)have been widely used to aid vehicular communications,we intend to utilize UAVs to assist sub-clusters in CP.In this paper,a UAV-aided CP network is constructed to fully utilize information from SRVs.First,the inter-node connection structure among the UAV and vehicles is designed to share available information from SRVs.After that,the clustering optimization strategy is proposed,in which the UAV cooperates with the high-precision sub-cluster to obtain available information from SRVs,and then broadcasts this positioning-related information to other low-precision sub-clusters.Finally,the Locally-Centralized Factor Graph Optimization(LC-FGO)algorithm is designed to fuse positioning information from cooperators.Simulation results indicate that the positioning accuracy of the CP system could be improved by fully utilizing positioning-related information from SRVs.展开更多
The legacy of United States cluster munition use in Laos and Cambodia during the Second Indochina War is residual bomblets that unexpectedly detonate years later, killing and injuring children, farmers, and other civi...The legacy of United States cluster munition use in Laos and Cambodia during the Second Indochina War is residual bomblets that unexpectedly detonate years later, killing and injuring children, farmers, and other civilians. Cluster munitions release dozens of smaller bomblets that rain deadly ammunition on troops, armored tanks, and vegetation, effectively striking broad sections of war zone landscapes in one launch. While many bomblets detonate immediately, others fail to detonate and can lie dormant on the ground for years. The primary objectives of this study were to document the long-term consequences and impacts of the US Air Force bombing of Laos and Cambodia during the Second Indochina War (1959 to 1973). The historical lessons learned by United States should be shared with Russia and Ukraine governments and military. These countries need to discontinue the use of cluster bombs to prevent additional people living along the Russia-Ukraine border from having to live and die with the consequences of unexploded ordnance, including cluster bombs, for the next century.展开更多
Customer segmentation according to load-shape profiles using smart meter data is an increasingly important application to vital the planning and operation of energy systems and to enable citizens’participation in the...Customer segmentation according to load-shape profiles using smart meter data is an increasingly important application to vital the planning and operation of energy systems and to enable citizens’participation in the energy transition.This study proposes an innovative multi-step clustering procedure to segment customers based on load-shape patterns at the daily and intra-daily time horizons.Smart meter data is split between daily and hourly normalized time series to assess monthly,weekly,daily,and hourly seasonality patterns separately.The dimensionality reduction implicit in the splitting allows a direct approach to clustering raw daily energy time series data.The intraday clustering procedure sequentially identifies representative hourly day-unit profiles for each customer and the entire population.For the first time,a step function approach is applied to reduce time series dimensionality.Customer attributes embedded in surveys are employed to build external clustering validation metrics using Cramer’s V correlation factors and to identify statistically significant determinants of load-shape in energy usage.In addition,a time series features engineering approach is used to extract 16 relevant demand flexibility indicators that characterize customers and corresponding clusters along four different axes:available Energy(E),Temporal patterns(T),Consistency(C),and Variability(V).The methodology is implemented on a real-world electricity consumption dataset of 325 Small and Medium-sized Enterprise(SME)customers,identifying 4 daily and 6 hourly easy-to-interpret,well-defined clusters.The application of the methodology includes selecting key parameters via grid search and a thorough comparison of clustering distances and methods to ensure the robustness of the results.Further research can test the scalability of the methodology to larger datasets from various customer segments(households and large commercial)and locations with different weather and socioeconomic conditions.展开更多
An aluminoborate,Na_(2.5)Rb[Al{B_(5)O_(10)}{B_(3)O_(5)}]·0.5NO_(3)·H_(2)O(1),was synthesized under hydrothermal condition,which was built by mixed oxoboron clusters and AlO_(4)tetrahedra.In the structure,the...An aluminoborate,Na_(2.5)Rb[Al{B_(5)O_(10)}{B_(3)O_(5)}]·0.5NO_(3)·H_(2)O(1),was synthesized under hydrothermal condition,which was built by mixed oxoboron clusters and AlO_(4)tetrahedra.In the structure,the[B_(5)O_(10)]^(5-)and[B_(3)O_(7)]^(5-)clusters are alternately connected to form 1D[B_(8)O_(15)]_(n)^(6n-)chains,which are further linked by AlO_(4)units to form a 2D monolayer with 7‑membered ring and 10‑membered ring windows.Two adjacent monolayers with opposite orientations further form a porous‑layered structure with six channels through B—O—Al bonds.Compound 1 was characterized by single crystal X‑ray diffraction,powder X‑ray diffraction(PXRD),IR spectroscopy,UV‑Vis diffuse reflection spectroscopy,and thermogravimetric analysis(TGA),respectively.UV‑Vis diffuse reflectance analysis indicates that compound 1 shows a wide transparency range with a short cutoff edge of 201 nm,suggesting it may have potential application in UV regions.CCDC:2383923.展开更多
Ultrafine,highly dispersed Pt clusters were immobilized onto the Co nanoparticle surfaces by one-step pyrolysis of the precursor Pt(Ⅱ)-encapsulating Co-MOF-74.Owing to the small size effects of Pt clusters as well as...Ultrafine,highly dispersed Pt clusters were immobilized onto the Co nanoparticle surfaces by one-step pyrolysis of the precursor Pt(Ⅱ)-encapsulating Co-MOF-74.Owing to the small size effects of Pt clusters as well as the strongly enhanced synergistic interactions between Pt and Co atoms,the obtained Pt-on-Co/C400 catalysts exhib-ited excellent catalytic activity toward the hydrolysis of ammonia borane with an extremely high turnover frequency(TOF)value of 3022 min^(-1)at 303 K.Durability test indicated that the obtained Pt-on-Co/C400 catalysts possessed high catalytic stability,and there were no changes in the catalyst structures and catalytic activities after 10 cycles.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.21901037,21901038 and 92161111)the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning+1 种基金the Fundamental Research Funds for the Central Universities(No.2232019G-07)the International Cooperation Fund of Science and Technology Commission of Shanghai Municipality(No.21130750100)。
文摘N-doping has significant influence in manipulating the properties of TiO_(2),and this has stimulated the development of N-donor-functionalized titanium-oxo clusters(TOCs)as molecular models to study the structure-property relationship.However,the structural type and photoresponsive application are still limited for such TOCs,especially regarding the high-nuclearity TOCs that contain structure unit of TiO_(2)for photocatalysis.Herein,we showed the synthesis of a series of high-nuclearity TOCs 1-3 compounds usingπ-conjugated 1,10-phenanthroline(phen)as chromophore and N-donor functional ligand.Compound 1 features cocrystal structure composed of one[Ti_(26)]~(2+)and half[Ti_(22)]~(2+),which renders it as the first cocrystallized TOC containing two positively charged species and phen-functionalized TOC showing the highest nuclearity up to 37 Ti centers.By adjusting the synthetic conditions,the individual{Ti_(22)}and{Ti_(26)}clusters can also be isolated as Compounds 2 and 3,respectively.The core structure of{Ti_(22)}is mainly constructed from four lacunary{Ti_(4)}derived from pentagonal{Ti(Ti)_5}unit,while{Ti_(26)}is built from four complete{Ti(Ti)_5}unit.Notably,a{Ti_8O_(14)}structure unit of anatase TiO_(2)can be identified in{Ti_(26)}.Based on the unique structural features and proper photophysical and photochemical properties of Compounds 1-3,they are applied for photocatalytic sulfoxidation.Owing to the presence of anatase structure unit in{Ti_(26)}and the synergistic effect from{Ti_(22)}and{Ti_(26)},the catalytic performance presents in the order of Compound 1>Compound 3>Compound 2.This work provides excellent models to understand the structureproperty relationship from the perspective of cocrystallization and Ti-O binding model and will further promote the application of TOCs as functional catalysts for organic transformation.
基金National Natural Science Foundation of China(Nos.92161111,21901037 and 21901038)。
文摘Photoactive functionalized titanium-oxo clusters(TOCs)are regarded as an important model compound for dye-sensitized titanium dioxide solar cells.However,the dyes used for sensitizing TOCs are still limited.Herein,two cyclic TOCs are reported,namely,[Ti_(6)(μ_(3)-O)_(2)(Oi-Pr)_(8))(LA)_(2)]·i-PrOH(S1)and[Ti_(6)(μ_(3)-O)2(Oi-Pr)_(8))(LV)_(2)]·i-PrOH(S2),which are functionalized by photoactive naphthalene diimide(NDI)chromophores.Their molecular structures and photophysical and photochemical properties were systematically studied.As shown by ultraviolet-visible(UV-vis)spectra and photocurrent study results,the band gap and the photocurrent response of S1 and S2 were derived from NDI ligands which extend the absorption edge of S1 and S2 approaching 500 nm and afford high photocurrent densities of 2.12μA/cm^(2)and 1.95μA/cm^(2)for S1 and S2,respectively,demonstrating the significance of the photoactive ligand in modulating photoresponse of TOCs.This work is expected to enrich the structural library of photoactive TOCs and provide insights into understanding the structure-property relationships of sensitized clusters.
基金supported by the National Natural Science Foundation of China (NSFC,No.21922111)the Strategic Priority Research Program of the Chinese Academy of Sciences (No.XDB20000000)。
文摘Supramolecular transformations of coordination cage or capsule have received much attention recently,which help elucidate this natural self-assembly behavior in biological systems.The current study describes the first supramolecular transformation of titanium-o rganic coordination capsule triggered by phenol(and H_(3) PO_(3)).The structural alterations are accompanied by the reconstruction of 5-coordinated Ti centers to 6-coordinated ones.Meanwhile,different amounts of encapsulated phenol vip molecules can be identified,dependent on the sizes of the obtained cavities.In addition,they display much better visible light absorption and air stability than the isopropanol stabilized ones.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.22325105,22201159,22171164,91961105,92361301,and 52261135637)the Natural Science Foundation of Shandong Province(Nos.ZR2021QB077 and ZR2024MB120)the Doctoral Program of Liaocheng University(No.318051944).
文摘The synthesis of titanium oxo clusters(TOCs)with both chirality and photoactivity is urgently needed to expand their applications.However,this remains a significant challenge due to synthetic difficulties and limitations in chiral ligand selection.In this work,we have isolated two pairs of enantiomeric TOCs,[Ti_(3)(μ_(3)-O)(R/S-L1)_(2)(^(i)PrO)_(6)](R/S-Ti_(3);^(i)PrOH=isopropanol,R/S-L1=R/S-2'-hydroxy-[1,1'-binaphthalen]-2-yl isopropyl hydrogenphosphate)and[Ti_(4)(μ_(2)-O)(μ_(4)-O)(R/S-L2)_(2)(EtO)_(8)](R/S-Ti4;EtOH=ethanol,R/S-L2=R/S-2'-hydroxy-[1,1'-binaphthalen]-2-yl ethyl hydrogenphosphate),via an in situ ligand transformation approach.The R/S-L1 and R/S-L2 ligands were obtained by alcoholysis of R/S-L(R/S-1,1'-binaphthyl-2,2'-diyl hydrogenphosphate)in different reaction solvents.These ligands,with additional coordination sites,facilitated the formation of novel TOCs and improved their stability.Importantly,these clusters exhibited exceptional stability in solid state and maintained appreciable stability in solution.Furthermore,the introduction of chiral ligands not only imparts a homochiral nature to R/S-Ti3 and R/S-Ti4 but also confers upon them superior photoelectric properties due to ligand-to-metal charge transfer(LMCT)phenomena,as confirmed by theoretical calculations.This study offers a valuable synthetic strategy for preparing photoactive chiral TOCs,and we anticipate it will inspire new discoveries in the field of chiral metal nanoclusters.
基金supported by the National Key R&D Program of China(Nos.2022YFA1502903 and 2021YFA1501502)the National Natural Science Foundation of China(Nos.22275179 and 92477116).
文摘Titanium-based materials have emerged as promising candidates for photo-Fenton-like catalysis,whereas their structural complexities impede precise understanding of the relevant structure–activity relationships.Owing to their well-defined and tunable structures,titaniumoxo clusters appear to be facile models for looking into the photophysical and photochemical processes in Ti-H_(2)O_(2) systems.Using PTC-3 as a prototype,we interrogated the relationship between Ti-site coordination environments and photo-Fenton-like behaviors.Through integrated in-situ/exsitu spectroscopic analyses and theoretical simulations,we elucidated light-driven H_(2)O_(2) activation on hexa-coordinated and penta-coordinated Ti sites in PTC-3.The superiority of penta-coordinated Ti site was identified,where extended visible-light absorption and promoted electron transfer could synergistically boost the activation of H_(2)O_(2) into superoxide radicals.This work brightens the role of Ti-site coordination geometry in photo-Fenton-like processes and paves the way for pursuing titanium-based advanced oxidation.
基金supported by the National Natural Science Foundation of China (21871224,92161104,92161203,21721001)。
文摘Molecular solid solutions of metal clusters containing different metal centers with well-defined structures can accurately regulate the HOMO-LUMO gap,but are rarely available.Herein,a series of colorless lanthanide-titanium-oxo clusters Ln_(2)Ti_4(μ_(2)-O)_(2)(μ_(3)-O)_4(Piv)_(10)(THF)_(2)(Ln_(2)Ti_4,Ln = Eu,Gd,Tb,and Ce,HPiv = pivalic acid) were synthesized by the reaction of pivalic acid with Ln(Ac)_(3) and titanium isopropoxide.The light yellow crystal of cluster solid solutions Eu_(2)Ti_(4-x)Cd_(x),containing a mixture of Eu_(2)Ti_4 and Eu_(2)Ti_(3)Cd,was obtained by in situ doping Cd^(2+) and S^(2–).Eu_(2)Ti_(3.92)Cd_(0.08) displays efficient photocatalytic hydrogen evolution activity without a co-catalyst,which is up to 2.6 times that of Eu_(2)Ti_4.Femtosecond time-resolved transient absorption spectroscopy and spin-polarized density functional calculations showed that the enhanced photocatalytic performance of Eu_(2)Ti_(4-x)Cd_(x) can be attributed to the narrower HOMO-LUMO gap and lower LUMO position than that of Eu_(2)Ti_4.This studyprovides an in situ doping method to realize the simple preparation of cluster solid solution.
基金National Natural Science Foundation of China,Grant/Award Numbers:U23A2095,22371278,92061104Science Fund for Distinguished Young Scholars of Fujian Province,Grant/Award Number:2021J06035+1 种基金Funding of Fujian Provincial Chemistry Discipline Alliance,Grant/Award Number:50025401Youth Innovation Promotion Association of the Chinese Academy of Sciences,Grant/Award Number:Y2021081。
文摘Compared with nanoparticle-aspect relatives titanium dioxide(TiO2),titanium-oxo clusters(TOCs)are atomically structural-determined and can be further precisely modified through coordination and supramolecular chemistry.Another parallel research direction is titanium-based metal-organic frameworks,and those based on TOC have attracted particular attention because of their high optical performances resulting from the cluster aggregation effect.Though challenging,assembling macro-materials from specific clusters helps establish the assembly chemistry of clusters and incorporates porous andflexible characteristics into a single bulk material.Although separate reviews are reported in these two branches,no com-prehensive review is available to highlight the bridges between them.Herein,we review and summarize the development and progress of new aggregation of TOCs,from intramolecular unique cluster aggregation to hierarchical intermolecular aggre-gation via covalent forces,coordination bonds,and non-covalent forces using the specific clusters as precursors.We hope this reviewfills the gap in the methodology of assembling particular-aggregated TOCs and their derived frameworks,providing general guidance to researchers interested in this area.
文摘Subject Code:B01 Photocatalytic hydrogen evolution by water-splitting has been recognized as one of the most promising solutions to the global energy and environment crisis,owing to its renewable solar energy source and clean chemical fuel product.Cadmium sulfide(CdS)and TiO2(or related polyoxo-titanium clusters)are two
基金supported by MOST(nos.2018YFA0208504 and 2017YFA0204702)NSFC(51773207,52073016,5197030531,and 21801213)of China+2 种基金The Fundamental Research Funds for the Central Universities further supported this work(no.XK1802-2)Open Project of State Key Laboratory of Supramolecular Structure and Materials(no.sklssm202043)Jiangxi Provincial Department of Science and Technology(nos.20192ACB20009,20192BBEL50026,20202ACBL213004,and 20203BBE53062).
文摘Perovskite and organic solar cells usually require electron-transport interlayers to efficiently transport electrons from the photoactive layer to the metal electrode.In general,pure organic or inorganic materials are applied into the interlayers,but organic–inorganic hybrid materials have been rarely reported for this application.In this work,we report using the first titanium-oxo cluster-based organic–inorganic hybrid as the interlayer material by introducing largeπ-conjugated benzo[ghi]perylenetriimides as an organic part via a simple ligand-exchange reaction.This new hybrid material showed excellent solubility,well-aligned energy levels,and excellent electron mobilities,enabling its great potential application as an interlayer in solar cells such as perovskite and organic solar cells,providing high power conversion efficiencies of>20%and 16%,respectively.Therefore,we claim that our present work introduces a new class of cluster-based organic–inorganic hybrid interlayer materials that exhibit promising application in organic electronics.
基金supported by the Foundation of President of Hebei University(XZJJ202303).
文摘Federated learning is a machine learning framework designed to protect privacy by keeping training data on clients’devices without sharing private data.It trains a global model through collaboration between clients and the server.However,the presence of data heterogeneity can lead to inefficient model training and even reduce the final model’s accuracy and generalization capability.Meanwhile,data scarcity can result in suboptimal cluster distributions for few-shot clients in centralized clustering tasks,and standalone personalization tasks may cause severe overfitting issues.To address these limitations,we introduce a federated learning dual optimization model based on clustering and personalization strategy(FedCPS).FedCPS adopts a decentralized approach,where clients identify their cluster membership locally without relying on a centralized clustering algorithm.Building on this,FedCPS introduces personalized training tasks locally,adding a regularization term to control deviations between local and cluster models.This improves the generalization ability of the final model while mitigating overfitting.The use of weight-sharing techniques also reduces the computational cost of central machines.Experimental results on MNIST,FMNIST,CIFAR10,and CIFAR100 datasets demonstrate that our method achieves better personalization effects compared to other personalized federated learning methods,with an average test accuracy improvement of 0.81%–2.96%.Meanwhile,we adjusted the proportion of few-shot clients to evaluate the impact on accuracy across different methods.The experiments show that FedCPS reduces accuracy by only 0.2%–3.7%,compared to 2.1%–10%for existing methods.Our method demonstrates its advantages across diverse data environments.
基金supported in part by NIH grants R01NS39600,U01MH114829RF1MH128693(to GAA)。
文摘Many fields,such as neuroscience,are experiencing the vast prolife ration of cellular data,underscoring the need fo r organizing and interpreting large datasets.A popular approach partitions data into manageable subsets via hierarchical clustering,but objective methods to determine the appropriate classification granularity are missing.We recently introduced a technique to systematically identify when to stop subdividing clusters based on the fundamental principle that cells must differ more between than within clusters.Here we present the corresponding protocol to classify cellular datasets by combining datadriven unsupervised hierarchical clustering with statistical testing.These general-purpose functions are applicable to any cellular dataset that can be organized as two-dimensional matrices of numerical values,including molecula r,physiological,and anatomical datasets.We demonstrate the protocol using cellular data from the Janelia MouseLight project to chara cterize morphological aspects of neurons.
基金supported by the National Natural Science Foundation of China(Nos.51977027 and 51967008)the Scientific and Technological Project of Yunnan Precious Metals Lab-oratory(Nos.YPML-2023050250 and YPML-2022050206).
文摘The pursuit of Ag-based alloys with both high strength and toughness has posed a longstanding chal-lenge.In this study,we investigated the cluster strengthening and grain refinement toughening mecha-nisms in fully oxidized AgMgNi alloys,which were internally oxidized at 800℃ for 8 h under an oxy-gen atmosphere.We found that Mg-O clusters contributed to the hardening(138 HV)and strengthening(376.9 MPa)of the AgMg alloy through solid solution strengthening effects,albeit at the expense of duc-tility.To address this limitation,we introduced Ni nanoparticles into the AgMg alloy,resulting in signifi-cant grain refinement within its microstructure.Specifically,the grain size decreased from 67.2μm in the oxidized AgMg alloy to below 6.0μm in the oxidized AgMgNi alloy containing 0.3 wt%Ni.Consequently,the toughness increased significantly,rising from toughness value of 2177.9 MJ m^(-3) in the oxidized AgMg alloy to 6186.1 MJ m^(-3) in the oxidized AgMgNi alloy,representing a remarkable 2.8-fold enhancement.Furthermore,the internally oxidized AgMgNi alloy attained a strength of up to 387.6 MPa,comparable to that of the internally oxidized AgMg alloy,thereby demonstrating the successful realization of concurrent strengthening and toughening.These results collectively offer a novel approach for the design of high-performance alloys through the synergistic combination of cluster strengthening and grain refinement toughening.
基金Supported by the PetroChina Science and Technology Major Project(2021ZZ01-05)Hainan Merit-based Recruitment Project(ZDYF2024SHFZ147)National Natural Science Foundation of China(NNSC)Project(52474033)。
文摘By systematically reviewing the development status of global carbon dioxide capture,utilization and storage(CCUS)cluster,and comparing domestic and international CCUS industrial models and successful experiences,this study explores the challenges and strategies for the scaled development of the CCUS industry of China.Globally,the CCUS industry has entered a phase of scaled and clustered development.North America has established a system of key technologies in large-scale CO_(2) capture,long-distance pipeline transmission,pipeline network optimization,and large-scale CO_(2) flooding for enhanced oil recovery(CO_(2)-EOR),with relatively mature cluster development and a gradual shift in industrial model from CO_(2)-EOR to geological storage.The CCUS industry of China has developed rapidly across all segments but remains in the early stage of cluster development,facing challenges such as absent business model,insufficient policy support,and technological gaps in core areas.China needs to improve the policy support system to boost enterprises participation across the entire industrial chain,strengthen top-level design and medium-to long-term planning to accelerate demonstration projects construction for whole-process CCUS clusters,advance for a full-chain technological system,including low-cost capture,pipeline optimization and EOR/storage integration technologies,and strengthen personnel training,strengthen discipline construction and university-enterprise research cooperation.
基金supported by the Natural Science Foundation of Jiangsu Province(No.BZ2022007)the National Natural Science Foundation of China(No.92261202)+1 种基金the Ministry of Science and Technology of the People’s Republic of China(No.2021YFE0114800)the Ministry of Science and Higher Education of the Russian Federation(No.075-15-2021-1027).
文摘Thermally activated delayed fluorescence(TADF)materials driven by a through-space charge transfer(TSCT)mechanism have garnered wide interest.However,access of TSCT-TADF molecules with longwavelength emission remains a formidable challenge.In this study,we introduce a novel V-type DA-D-A’emitter,Trz-mCzCbCz,by using a carborane scaffold.This design strategically incorporates carbazole(Cz)and 2,4,6-triphenyl-1,3,5-triazine(Trz)as donor and acceptor moieties,respectively.Theoretical calculations alongside experimental validations affirm the typical TSCT-TADF characteristics of this luminogen.Owing to the unique structural and electronic attributes of carboranes,Trz-mCzCbCz exhibits an orange-red emission,markedly diverging from the traditional blue-to-green emissions observed in classical Cz and Trz-based TADF molecules.Moreover,bright emission in aggregates was observed for Trz-mCzCbCz with absolute photoluminescence quantum yield(PLQY)of up to 88.8%.As such,we have successfully fabricated five organic light-emitting diodes(OLEDs)by utilizing Trz-mCzCbCz as the emitting layer.It is important to note that both the reverse intersystem crossing process and the TADF properties are profoundly influenced by host materials.The fabricated OLED devices reached a maximum external quantum efficiency(EQE)of 12.7%,with an emission peak at 592 nm.This represents the highest recorded efficiency for TSCT-TADF OLEDs employing carborane derivatives as emitting layers.
基金supported by the National Natural Science Foundation of China(No.62271399)the National Key Research and Development Program of China(No.2022YFB1807102)。
文摘For multi-vehicle networks,Cooperative Positioning(CP)technique has become a promising way to enhance vehicle positioning accuracy.Especially,the CP performance could be further improved by introducing Sensor-Rich Vehicles(SRVs)into CP networks,which is called SRV-aided CP.However,the CP system may split into several sub-clusters that cannot be connected with each other in dense urban environments,in which the sub-clusters with few SRVs will suffer from degradation of CP performance.Since Unmanned Aerial Vehicles(UAVs)have been widely used to aid vehicular communications,we intend to utilize UAVs to assist sub-clusters in CP.In this paper,a UAV-aided CP network is constructed to fully utilize information from SRVs.First,the inter-node connection structure among the UAV and vehicles is designed to share available information from SRVs.After that,the clustering optimization strategy is proposed,in which the UAV cooperates with the high-precision sub-cluster to obtain available information from SRVs,and then broadcasts this positioning-related information to other low-precision sub-clusters.Finally,the Locally-Centralized Factor Graph Optimization(LC-FGO)algorithm is designed to fuse positioning information from cooperators.Simulation results indicate that the positioning accuracy of the CP system could be improved by fully utilizing positioning-related information from SRVs.
文摘The legacy of United States cluster munition use in Laos and Cambodia during the Second Indochina War is residual bomblets that unexpectedly detonate years later, killing and injuring children, farmers, and other civilians. Cluster munitions release dozens of smaller bomblets that rain deadly ammunition on troops, armored tanks, and vegetation, effectively striking broad sections of war zone landscapes in one launch. While many bomblets detonate immediately, others fail to detonate and can lie dormant on the ground for years. The primary objectives of this study were to document the long-term consequences and impacts of the US Air Force bombing of Laos and Cambodia during the Second Indochina War (1959 to 1973). The historical lessons learned by United States should be shared with Russia and Ukraine governments and military. These countries need to discontinue the use of cluster bombs to prevent additional people living along the Russia-Ukraine border from having to live and die with the consequences of unexploded ordnance, including cluster bombs, for the next century.
基金supported by the Spanish Ministry of Science and Innovation under Projects PID2022-137680OB-C32 and PID2022-139187OB-I00.
文摘Customer segmentation according to load-shape profiles using smart meter data is an increasingly important application to vital the planning and operation of energy systems and to enable citizens’participation in the energy transition.This study proposes an innovative multi-step clustering procedure to segment customers based on load-shape patterns at the daily and intra-daily time horizons.Smart meter data is split between daily and hourly normalized time series to assess monthly,weekly,daily,and hourly seasonality patterns separately.The dimensionality reduction implicit in the splitting allows a direct approach to clustering raw daily energy time series data.The intraday clustering procedure sequentially identifies representative hourly day-unit profiles for each customer and the entire population.For the first time,a step function approach is applied to reduce time series dimensionality.Customer attributes embedded in surveys are employed to build external clustering validation metrics using Cramer’s V correlation factors and to identify statistically significant determinants of load-shape in energy usage.In addition,a time series features engineering approach is used to extract 16 relevant demand flexibility indicators that characterize customers and corresponding clusters along four different axes:available Energy(E),Temporal patterns(T),Consistency(C),and Variability(V).The methodology is implemented on a real-world electricity consumption dataset of 325 Small and Medium-sized Enterprise(SME)customers,identifying 4 daily and 6 hourly easy-to-interpret,well-defined clusters.The application of the methodology includes selecting key parameters via grid search and a thorough comparison of clustering distances and methods to ensure the robustness of the results.Further research can test the scalability of the methodology to larger datasets from various customer segments(households and large commercial)and locations with different weather and socioeconomic conditions.
文摘An aluminoborate,Na_(2.5)Rb[Al{B_(5)O_(10)}{B_(3)O_(5)}]·0.5NO_(3)·H_(2)O(1),was synthesized under hydrothermal condition,which was built by mixed oxoboron clusters and AlO_(4)tetrahedra.In the structure,the[B_(5)O_(10)]^(5-)and[B_(3)O_(7)]^(5-)clusters are alternately connected to form 1D[B_(8)O_(15)]_(n)^(6n-)chains,which are further linked by AlO_(4)units to form a 2D monolayer with 7‑membered ring and 10‑membered ring windows.Two adjacent monolayers with opposite orientations further form a porous‑layered structure with six channels through B—O—Al bonds.Compound 1 was characterized by single crystal X‑ray diffraction,powder X‑ray diffraction(PXRD),IR spectroscopy,UV‑Vis diffuse reflection spectroscopy,and thermogravimetric analysis(TGA),respectively.UV‑Vis diffuse reflectance analysis indicates that compound 1 shows a wide transparency range with a short cutoff edge of 201 nm,suggesting it may have potential application in UV regions.CCDC:2383923.
文摘Ultrafine,highly dispersed Pt clusters were immobilized onto the Co nanoparticle surfaces by one-step pyrolysis of the precursor Pt(Ⅱ)-encapsulating Co-MOF-74.Owing to the small size effects of Pt clusters as well as the strongly enhanced synergistic interactions between Pt and Co atoms,the obtained Pt-on-Co/C400 catalysts exhib-ited excellent catalytic activity toward the hydrolysis of ammonia borane with an extremely high turnover frequency(TOF)value of 3022 min^(-1)at 303 K.Durability test indicated that the obtained Pt-on-Co/C400 catalysts possessed high catalytic stability,and there were no changes in the catalyst structures and catalytic activities after 10 cycles.
