Covalent organic frameworks(COFs)have demonstrated great potential in chromatographic separation because of unique structure and superior performance.Herein,single-crystal three-dimensional(3D)COFs with regular morpho...Covalent organic frameworks(COFs)have demonstrated great potential in chromatographic separation because of unique structure and superior performance.Herein,single-crystal three-dimensional(3D)COFs with regular morphology,good monodispersity and high specific surface area,were used as a stationary phase for high-performance liquid chromatography(HPLC).The single-crystal 3D COFs packed column not only exhibits high efficiency in separating hydrophobic molecules involving substituted benzenes,halogenated benzenes,halogenated nitrobenzenes,aromatic amines,aromatic hydrocarbons(PAHs)and phthalate esters(PAEs),but also achieves baseline separation of acenaphthene and acenaphthylene with similar physical and chemical properties as well as environmental pollutants,which cannot be quickly separated on commercial C18 column and a polycrystalline 3D COFs packed column.Especially,the column efficiency of 17303-24255 plates/m was obtained for PAEs,and the resolution values for acenaphthene and acenaphthylene,and carbamazepine(CBZ)and carbamazepine-10,11-epoxide(CBZEP)were 1.7and 2.2,respectively.This successful application not only confirmed the great potential of the singlecrystal 3D COFs in HPLC separation of the organic molecules,but also facilitates the application of COFs in separation science.展开更多
Compared to subtractive manufacturing and casting,3D printing(additive manufacturing)offers advantages,such as the rapid production of complex structures,reduced material waste,and environmental friendliness.Direct in...Compared to subtractive manufacturing and casting,3D printing(additive manufacturing)offers advantages,such as the rapid production of complex structures,reduced material waste,and environmental friendliness.Direct ink writing(DIW)is one of the most popular 3D printing techniques owing to its ability to print multiple materials simultaneously and its high compatibility with printing inks.However,DIW presents significant challenges,particularly in the printing of high-performance polymers.The main challenges are as follows:1.The rigid structures and reaction kinetics of high-performance polymers make developing new inks difficult.2.The limited types of available high-performance polymers underscore the need for new DIW-suitable materials.3.Layer-by-layer stacking weakens interlayer bonding,affecting the mechanical properties of the printed product.4.The accuracy and speed of DIW printing are insufficient for large-scale manufacturing.After introducing the topic,the requirements for DIW printing inks are first reviewed,emphasizing the importance of thixotropic agents.Then,research progress regarding DIW printing of high-performance polymers is comprehensively reviewed according to the requirements of different polymer inks.Additionally,the applications of these materials across various fields are summarized.Finally,the challenges in DIW printing of high-performance polymers,along with corresponding solutions and future development prospects,are discussed in detail.展开更多
Exploring platinum single-atom electrocatalysts(SACs)is of great significance for effectively catalyzing the hydrogen evolution reaction in order to maximize the utilization of metal atoms.Herein,ruthenium clusters wi...Exploring platinum single-atom electrocatalysts(SACs)is of great significance for effectively catalyzing the hydrogen evolution reaction in order to maximize the utilization of metal atoms.Herein,ruthenium clusters with several atoms(Rux)supported on nitrogen-doped,cost-efficient Black Pearls 2000(Ru_(x)NBP),were synthesized as initial materials via a simple hydrothermal method.Then,[PtCl_(4)]^(2–)ion was reductively deposited on RuxNBP to obtain a Pt SAC(Pt1/RuxNBP).Electrochemical measurements demonstrate the excellent HER performance of Pt_(1)/Ru_(x)NBP with a 5.7-fold increase in mass activity compared to the commercial Pt/C at 20 mV.Moreover,the cell voltage of the proton exchange membrane electrolyzer with Pt_(1)/Ru_(x)NBP is 20 mV lower compared to that with commercial Pt/C at 1.0 A cm^(−2).Physical characterization and density functional theory calculations revealed that the preserved Pt–Cl bond of[PtCl_(4)]^(2–)and the RuxNBP support co-regulate the 5d state of isolated Pt atoms and enhance the catalytic HER capacity of Pt1/RuxNBP.展开更多
Incorporating low-concentration precious metals into transition metal phosphides(TMPs)may represent a promising strategy to achieve improved catalytic performance of oxygen evolution reaction(OER).We design RuP_(4)clu...Incorporating low-concentration precious metals into transition metal phosphides(TMPs)may represent a promising strategy to achieve improved catalytic performance of oxygen evolution reaction(OER).We design RuP_(4)clusters immobilized on porous NiFeP nanosheets with Ru-P/O-TM bridge(RuP-NiFeP)for effective OER.The Ru-P/O-Ni/Fe bridges formed between the RuP_(4)clusters and the NiFeP facilitate electron transfer between oxyphilic Ru atoms and Ni/Fe atoms,enabling Ru to achieve optimized reactant/intermediate adsorption.Advanced characterizations and theoretical calculations reveal that the incorporation of Ru species leads to the upshift of d band center and the formation of more disorderedγ-NiOOH.The Ru-based clusters and the achieved disorderedγ-NiOOH may deliver synergistic effect to further enhance the OER capability of RuP-NiFeP.Moreover,the presence of Ru species shifts the OER mechanism from the absorbate evolution mechanism(AEM)pathway(NiFeP)to the lattice oxygen mechanism(LOM)pathway,with*OH deprotonation(*OH→*O)as the rate-determining step(RDS).The RuP-NiFeP catalyst exhibits remarkable alkaline OER activity,requiring only an overpotential of 225 mV to achieve a current density of 100 mA cm^(−2),and retains its performance with a minimal current density decay of 1.9%after stability test.This work offers valuable insights into the design of cost-effective and highly efficient electrocatalysts for alkaline OER.展开更多
Magnesium(Mg),being the lightest structural metal,holds immense potential for widespread applications in various fields.The development of high-performance and cost-effective Mg alloys is crucial to further advancing ...Magnesium(Mg),being the lightest structural metal,holds immense potential for widespread applications in various fields.The development of high-performance and cost-effective Mg alloys is crucial to further advancing their commercial utilization.With the rapid advancement of machine learning(ML)technology in recent years,the“data-driven''approach for alloy design has provided new perspectives and opportunities for enhancing the performance of Mg alloys.This paper introduces a novel regression-based Bayesian optimization active learning model(RBOALM)for the development of high-performance Mg-Mn-based wrought alloys.RBOALM employs active learning to automatically explore optimal alloy compositions and process parameters within predefined ranges,facilitating the discovery of superior alloy combinations.This model further integrates pre-established regression models as surrogate functions in Bayesian optimization,significantly enhancing the precision of the design process.Leveraging RBOALM,several new high-performance alloys have been successfully designed and prepared.Notably,after mechanical property testing of the designed alloys,the Mg-2.1Zn-2.0Mn-0.5Sn-0.1Ca alloy demonstrates exceptional mechanical properties,including an ultimate tensile strength of 406 MPa,a yield strength of 287 MPa,and a 23%fracture elongation.Furthermore,the Mg-2.7Mn-0.5Al-0.1Ca alloy exhibits an ultimate tensile strength of 211 MPa,coupled with a remarkable 41%fracture elongation.展开更多
The increasing demand for high-end equipment in crucial sectors such as aerospace,aeronautics, energy, power, information and electronics continues growing. However, the manufacturing of such advanced equipment poses ...The increasing demand for high-end equipment in crucial sectors such as aerospace,aeronautics, energy, power, information and electronics continues growing. However, the manufacturing of such advanced equipment poses significant challenges owing to high-level requirements for loading, transmission, conduction, energy conversion, and stealth. These challenges are amplified by complex structures, hard-to-cut materials, and strict standards for surface integrity and precision. To overcome these barriers in high-end equipment manufacturing, high-performance manufacturing(HPM) has emerged as an essential solution.This paper firstly discusses the key challenges in manufacturing technology and explores the essence of HPM, outlining a quantitative relationship between design and manufacturing.Subsequently, a generalized framework of HPM is proposed, accompanied by an in-depth exploration of the foundational elements and criteria. Ultimately, the feasible approaches and enabling technologies, supported by the analysis of two illustrative case studies are demonstrated. It is concluded that HPM is not just a precision and computational manufacturing framework with a core focus on multiparameter correlation in design, manufacturing, and service environments. It also represents a performance-geometry-integrated manufacturing framework for an accurate guarantee of the optimal performance.展开更多
It is a difficult challenge to simultaneously employ the cationic and anionic redox chemistry in cathode materials for sodium-ion batteries with high energy.Even though layered oxides(classified as two-dimensional oxi...It is a difficult challenge to simultaneously employ the cationic and anionic redox chemistry in cathode materials for sodium-ion batteries with high energy.Even though layered oxides(classified as two-dimensional oxides)demonstrate excellent promise in the high discharge capacity,their poor oxygen transformation via redox reactions is limited by crystal instability.Therefore,a doping strategy was conceived to tackle this issue and increase redox efficiency.K doping was applied to transform the two-dimensional Na_(1.3)Mn_(0.7)O_(2)(NMO)to threedimensional K_(0.2)Na_(1.3)Mn_(0.5)O_(2)(KNMO),preventing the irreversible phase shift and preserving the crystal structure’s stability while cycling.With this modification treatment,KNMO features manganese and oxygen reactive sites,delivering a promising energy density of 190mAh·g^(-1)at 5 mA·g^(-1)in the 2.0–4.5 V voltage range(vs71.4 mAh·g^(-1)for the pristine NMO).Moreover,it displays improved capacity retention of more than 83.5%after 50cycles at 50 mA·g^(-1).The results demonstrated that doped intercalation oxides were promising for redox oxygen transformation in sodium-ion batteries.展开更多
Rational design and synthesis of low-cost trifunctional electrocatalysts with improved stability and superior electrocatalytic activity for oxygen reduction reaction(ORR),oxygen evolution reaction(OER),and hydrogen ev...Rational design and synthesis of low-cost trifunctional electrocatalysts with improved stability and superior electrocatalytic activity for oxygen reduction reaction(ORR),oxygen evolution reaction(OER),and hydrogen evolution reaction(HER) are highly desirable but remain as the bottlenecks at the current state of technology.In this paper,the cobalt-iron(Co-Fe) composite supported on nitrogen-doped carbon nanotubes(CoFe composite/NCNTs) is synthesized.The intrinsic OER and HER catalytic activities of this CoFe composite/NCNTs composite are significantly improved with palladium(Pd) nanocluster decoration [Pd-coated(CoFe composite/NCNTs)].The as-prepared Pd-coated(CoFe composite/NCNTs) catalyst exhibits excellent trifunctional electrocatalytic activity and stability due to the interfacial coupling between Pd and(CoFe composite/NCNTs).This catalyst is successfully employed in the water electrolysis cell as both OER and HER electrode catalysts,flexible rechargeable Zn-air battery as the bifunctional ORR and OER electrode catalyst.The cell voltage of this catalyst-coated electrodes requires only 1.60 V to achieve 10 mA cm^(-2) current density for water electrolysis cell,which is comparable to and even better than that of Pt/C and Ir/C based cell.The primary Zn-air battery using this catalyst shows a constant high open-circuit voltage(OCV) of 1.47 V and a maximum power density of 261 mW cm^(-2) in the flooded mode configuration.Most importantly,a flexible Zn-air battery with this catalyst runs very smoothly without a change in voltage gap during flat,bending,and twisting positions.展开更多
Two-dimensional metal dichalcogenides have been evidenced as potential electrocatalysts for hydrogen evolution reaction(HER);however,their application is limited by a poor oxygen evolution reaction(OER)activity due to...Two-dimensional metal dichalcogenides have been evidenced as potential electrocatalysts for hydrogen evolution reaction(HER);however,their application is limited by a poor oxygen evolution reaction(OER)activity due to insufficient number/types of multi-integrated active sites.In this study,we report a novel bifunctional catalyst developed by simultaneous engineering of single nickel atoms(Ni_(SA)) and nickel phosphate clusters(Ni_(Pi)) to synergistically trigger surface-functionalized MoS_(2) nanosheets(NSs)resulting in high reactivities for both HER and OER.The Ni_(SA)-Ni_(Pi)/MoS_(2)NSs material exhibits a fairly Pt-like HER behavior with an overpotential of 94.0 mV and a small OER overpotential of 314.0 mV to reach 10 mA cm^(-2) in freshwater containing 1.0 M KOH.Experimental results of the catalyst are well supported by theoretical study,which reveals the significant modulation of electronic structure and enrichment of electroactive site number/types with their reasonably adjusted free adsorption energy.For evaluating practicability,the Ni_(SA)-Ni_(Pi)/MoS_(2)NSs-based electrolyzer delivers effective operation voltage of 1.62,1.52,and 1.66 V at 10 mA cm^(-2) and superior long-term stability as compared to Pt/C//RuO_(2) system in freshwater,mimic seawater,and natural seawater,respectively.The present study indicates that the catalyst is a promising candidate for the practical production of green hydrogen via water electrolysis.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
Carbendazim belongs to the benzimidazole fungicides,which can be used for control lots of fungi pathogens.High-performance liquid chromatography is frequently used for the analysis of carbendazim in all kinds of sampl...Carbendazim belongs to the benzimidazole fungicides,which can be used for control lots of fungi pathogens.High-performance liquid chromatography is frequently used for the analysis of carbendazim in all kinds of samples.In most occasions,the developed methods were applied for the simultaneous detection of a huge number of pesticides.Thus,an analytical method via UPLC-FLD was developed,and the sample preparation process was optimized by studying the effect of extraction solvent,approach,time and purification absorbent on the recovery rate of carbendazim.The results showed the optimized method for analysis was ultrasonication-assisted extraction with acetonitrile for 1 min,and subsequent purification by C18.In this occasion,the established analytical method of carbendazim in tomato samples displayed good linearity,accuracy and precision.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
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the National Natural Science Foundation of China(No.22274021)Natural Science Foundation of Fujian Province(No.2022J01535)for financial support。
文摘Covalent organic frameworks(COFs)have demonstrated great potential in chromatographic separation because of unique structure and superior performance.Herein,single-crystal three-dimensional(3D)COFs with regular morphology,good monodispersity and high specific surface area,were used as a stationary phase for high-performance liquid chromatography(HPLC).The single-crystal 3D COFs packed column not only exhibits high efficiency in separating hydrophobic molecules involving substituted benzenes,halogenated benzenes,halogenated nitrobenzenes,aromatic amines,aromatic hydrocarbons(PAHs)and phthalate esters(PAEs),but also achieves baseline separation of acenaphthene and acenaphthylene with similar physical and chemical properties as well as environmental pollutants,which cannot be quickly separated on commercial C18 column and a polycrystalline 3D COFs packed column.Especially,the column efficiency of 17303-24255 plates/m was obtained for PAEs,and the resolution values for acenaphthene and acenaphthylene,and carbamazepine(CBZ)and carbamazepine-10,11-epoxide(CBZEP)were 1.7and 2.2,respectively.This successful application not only confirmed the great potential of the singlecrystal 3D COFs in HPLC separation of the organic molecules,but also facilitates the application of COFs in separation science.
基金supported by National Key Research and Development Program of China(Grant No.2022YFB3809000)Major Science and Technology Project of Gansu Province(Grant No.23ZDGA011)+1 种基金National Natural Science Foundation of China(Grant No.22275199,52105224)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB04701022021).
文摘Compared to subtractive manufacturing and casting,3D printing(additive manufacturing)offers advantages,such as the rapid production of complex structures,reduced material waste,and environmental friendliness.Direct ink writing(DIW)is one of the most popular 3D printing techniques owing to its ability to print multiple materials simultaneously and its high compatibility with printing inks.However,DIW presents significant challenges,particularly in the printing of high-performance polymers.The main challenges are as follows:1.The rigid structures and reaction kinetics of high-performance polymers make developing new inks difficult.2.The limited types of available high-performance polymers underscore the need for new DIW-suitable materials.3.Layer-by-layer stacking weakens interlayer bonding,affecting the mechanical properties of the printed product.4.The accuracy and speed of DIW printing are insufficient for large-scale manufacturing.After introducing the topic,the requirements for DIW printing inks are first reviewed,emphasizing the importance of thixotropic agents.Then,research progress regarding DIW printing of high-performance polymers is comprehensively reviewed according to the requirements of different polymer inks.Additionally,the applications of these materials across various fields are summarized.Finally,the challenges in DIW printing of high-performance polymers,along with corresponding solutions and future development prospects,are discussed in detail.
文摘Exploring platinum single-atom electrocatalysts(SACs)is of great significance for effectively catalyzing the hydrogen evolution reaction in order to maximize the utilization of metal atoms.Herein,ruthenium clusters with several atoms(Rux)supported on nitrogen-doped,cost-efficient Black Pearls 2000(Ru_(x)NBP),were synthesized as initial materials via a simple hydrothermal method.Then,[PtCl_(4)]^(2–)ion was reductively deposited on RuxNBP to obtain a Pt SAC(Pt1/RuxNBP).Electrochemical measurements demonstrate the excellent HER performance of Pt_(1)/Ru_(x)NBP with a 5.7-fold increase in mass activity compared to the commercial Pt/C at 20 mV.Moreover,the cell voltage of the proton exchange membrane electrolyzer with Pt_(1)/Ru_(x)NBP is 20 mV lower compared to that with commercial Pt/C at 1.0 A cm^(−2).Physical characterization and density functional theory calculations revealed that the preserved Pt–Cl bond of[PtCl_(4)]^(2–)and the RuxNBP support co-regulate the 5d state of isolated Pt atoms and enhance the catalytic HER capacity of Pt1/RuxNBP.
基金supported by the Australian Research Council(DE240100868)CSIRO“International Hydrogen Research Collaboration Program-RESEARCH FELLOWSHIPS”+3 种基金the National Natural Science Foundation of China(22209103)the UTS Chancellor's Research Fellowshipssupport from the “Joint International Laboratory on Environmental and Energy Frontier Materials” and the “Innovation Research Team of High-Level Local Universities in Shanghai”Supported by Computing, Shanghai University
文摘Incorporating low-concentration precious metals into transition metal phosphides(TMPs)may represent a promising strategy to achieve improved catalytic performance of oxygen evolution reaction(OER).We design RuP_(4)clusters immobilized on porous NiFeP nanosheets with Ru-P/O-TM bridge(RuP-NiFeP)for effective OER.The Ru-P/O-Ni/Fe bridges formed between the RuP_(4)clusters and the NiFeP facilitate electron transfer between oxyphilic Ru atoms and Ni/Fe atoms,enabling Ru to achieve optimized reactant/intermediate adsorption.Advanced characterizations and theoretical calculations reveal that the incorporation of Ru species leads to the upshift of d band center and the formation of more disorderedγ-NiOOH.The Ru-based clusters and the achieved disorderedγ-NiOOH may deliver synergistic effect to further enhance the OER capability of RuP-NiFeP.Moreover,the presence of Ru species shifts the OER mechanism from the absorbate evolution mechanism(AEM)pathway(NiFeP)to the lattice oxygen mechanism(LOM)pathway,with*OH deprotonation(*OH→*O)as the rate-determining step(RDS).The RuP-NiFeP catalyst exhibits remarkable alkaline OER activity,requiring only an overpotential of 225 mV to achieve a current density of 100 mA cm^(−2),and retains its performance with a minimal current density decay of 1.9%after stability test.This work offers valuable insights into the design of cost-effective and highly efficient electrocatalysts for alkaline OER.
基金supported by the National Natural the Science Foundation of China(51971042,51901028)the Chongqing Academician Special Fund(cstc2020yszxjcyj X0001)+1 种基金the China Scholarship Council(CSC)Norwegian University of Science and Technology(NTNU)for their financial and technical support。
文摘Magnesium(Mg),being the lightest structural metal,holds immense potential for widespread applications in various fields.The development of high-performance and cost-effective Mg alloys is crucial to further advancing their commercial utilization.With the rapid advancement of machine learning(ML)technology in recent years,the“data-driven''approach for alloy design has provided new perspectives and opportunities for enhancing the performance of Mg alloys.This paper introduces a novel regression-based Bayesian optimization active learning model(RBOALM)for the development of high-performance Mg-Mn-based wrought alloys.RBOALM employs active learning to automatically explore optimal alloy compositions and process parameters within predefined ranges,facilitating the discovery of superior alloy combinations.This model further integrates pre-established regression models as surrogate functions in Bayesian optimization,significantly enhancing the precision of the design process.Leveraging RBOALM,several new high-performance alloys have been successfully designed and prepared.Notably,after mechanical property testing of the designed alloys,the Mg-2.1Zn-2.0Mn-0.5Sn-0.1Ca alloy demonstrates exceptional mechanical properties,including an ultimate tensile strength of 406 MPa,a yield strength of 287 MPa,and a 23%fracture elongation.Furthermore,the Mg-2.7Mn-0.5Al-0.1Ca alloy exhibits an ultimate tensile strength of 211 MPa,coupled with a remarkable 41%fracture elongation.
文摘The increasing demand for high-end equipment in crucial sectors such as aerospace,aeronautics, energy, power, information and electronics continues growing. However, the manufacturing of such advanced equipment poses significant challenges owing to high-level requirements for loading, transmission, conduction, energy conversion, and stealth. These challenges are amplified by complex structures, hard-to-cut materials, and strict standards for surface integrity and precision. To overcome these barriers in high-end equipment manufacturing, high-performance manufacturing(HPM) has emerged as an essential solution.This paper firstly discusses the key challenges in manufacturing technology and explores the essence of HPM, outlining a quantitative relationship between design and manufacturing.Subsequently, a generalized framework of HPM is proposed, accompanied by an in-depth exploration of the foundational elements and criteria. Ultimately, the feasible approaches and enabling technologies, supported by the analysis of two illustrative case studies are demonstrated. It is concluded that HPM is not just a precision and computational manufacturing framework with a core focus on multiparameter correlation in design, manufacturing, and service environments. It also represents a performance-geometry-integrated manufacturing framework for an accurate guarantee of the optimal performance.
基金financially supported by the Scientific Research Startup Fund for Shenzhen High-Caliber Personnel of SZPT(No.6021310029K)Research Projects of Department of Education of Guangdong Province(No.2023KTSCX319)。
文摘It is a difficult challenge to simultaneously employ the cationic and anionic redox chemistry in cathode materials for sodium-ion batteries with high energy.Even though layered oxides(classified as two-dimensional oxides)demonstrate excellent promise in the high discharge capacity,their poor oxygen transformation via redox reactions is limited by crystal instability.Therefore,a doping strategy was conceived to tackle this issue and increase redox efficiency.K doping was applied to transform the two-dimensional Na_(1.3)Mn_(0.7)O_(2)(NMO)to threedimensional K_(0.2)Na_(1.3)Mn_(0.5)O_(2)(KNMO),preventing the irreversible phase shift and preserving the crystal structure’s stability while cycling.With this modification treatment,KNMO features manganese and oxygen reactive sites,delivering a promising energy density of 190mAh·g^(-1)at 5 mA·g^(-1)in the 2.0–4.5 V voltage range(vs71.4 mAh·g^(-1)for the pristine NMO).Moreover,it displays improved capacity retention of more than 83.5%after 50cycles at 50 mA·g^(-1).The results demonstrated that doped intercalation oxides were promising for redox oxygen transformation in sodium-ion batteries.
基金the support of the National Nature Science Foundation of China (21908124)Zhaoqing Xijiang Talent Program。
文摘Rational design and synthesis of low-cost trifunctional electrocatalysts with improved stability and superior electrocatalytic activity for oxygen reduction reaction(ORR),oxygen evolution reaction(OER),and hydrogen evolution reaction(HER) are highly desirable but remain as the bottlenecks at the current state of technology.In this paper,the cobalt-iron(Co-Fe) composite supported on nitrogen-doped carbon nanotubes(CoFe composite/NCNTs) is synthesized.The intrinsic OER and HER catalytic activities of this CoFe composite/NCNTs composite are significantly improved with palladium(Pd) nanocluster decoration [Pd-coated(CoFe composite/NCNTs)].The as-prepared Pd-coated(CoFe composite/NCNTs) catalyst exhibits excellent trifunctional electrocatalytic activity and stability due to the interfacial coupling between Pd and(CoFe composite/NCNTs).This catalyst is successfully employed in the water electrolysis cell as both OER and HER electrode catalysts,flexible rechargeable Zn-air battery as the bifunctional ORR and OER electrode catalyst.The cell voltage of this catalyst-coated electrodes requires only 1.60 V to achieve 10 mA cm^(-2) current density for water electrolysis cell,which is comparable to and even better than that of Pt/C and Ir/C based cell.The primary Zn-air battery using this catalyst shows a constant high open-circuit voltage(OCV) of 1.47 V and a maximum power density of 261 mW cm^(-2) in the flooded mode configuration.Most importantly,a flexible Zn-air battery with this catalyst runs very smoothly without a change in voltage gap during flat,bending,and twisting positions.
基金supported by the Regional Leading Research Center Program(2019R1A5A8080326)Basic Science Research Program(2020R1F1A1075921)BRL Program(2020R1A4A1018259)through the National Research Foundation(NRF)funded by the Ministry of Science and ICT of Republic of Korea.
文摘Two-dimensional metal dichalcogenides have been evidenced as potential electrocatalysts for hydrogen evolution reaction(HER);however,their application is limited by a poor oxygen evolution reaction(OER)activity due to insufficient number/types of multi-integrated active sites.In this study,we report a novel bifunctional catalyst developed by simultaneous engineering of single nickel atoms(Ni_(SA)) and nickel phosphate clusters(Ni_(Pi)) to synergistically trigger surface-functionalized MoS_(2) nanosheets(NSs)resulting in high reactivities for both HER and OER.The Ni_(SA)-Ni_(Pi)/MoS_(2)NSs material exhibits a fairly Pt-like HER behavior with an overpotential of 94.0 mV and a small OER overpotential of 314.0 mV to reach 10 mA cm^(-2) in freshwater containing 1.0 M KOH.Experimental results of the catalyst are well supported by theoretical study,which reveals the significant modulation of electronic structure and enrichment of electroactive site number/types with their reasonably adjusted free adsorption energy.For evaluating practicability,the Ni_(SA)-Ni_(Pi)/MoS_(2)NSs-based electrolyzer delivers effective operation voltage of 1.62,1.52,and 1.66 V at 10 mA cm^(-2) and superior long-term stability as compared to Pt/C//RuO_(2) system in freshwater,mimic seawater,and natural seawater,respectively.The present study indicates that the catalyst is a promising candidate for the practical production of green hydrogen via water electrolysis.
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 by Youth Talent Project of Education Department Scientific Research Plan of Hubei Province(Q20232904).
文摘Carbendazim belongs to the benzimidazole fungicides,which can be used for control lots of fungi pathogens.High-performance liquid chromatography is frequently used for the analysis of carbendazim in all kinds of samples.In most occasions,the developed methods were applied for the simultaneous detection of a huge number of pesticides.Thus,an analytical method via UPLC-FLD was developed,and the sample preparation process was optimized by studying the effect of extraction solvent,approach,time and purification absorbent on the recovery rate of carbendazim.The results showed the optimized method for analysis was ultrasonication-assisted extraction with acetonitrile for 1 min,and subsequent purification by C18.In this occasion,the established analytical method of carbendazim in tomato samples displayed good linearity,accuracy and precision.
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 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.
