Recognizing human interactions in RGB videos is a critical task in computer vision,with applications in video surveillance.Existing deep learning-based architectures have achieved strong results,but are computationall...Recognizing human interactions in RGB videos is a critical task in computer vision,with applications in video surveillance.Existing deep learning-based architectures have achieved strong results,but are computationally intensive,sensitive to video resolution changes and often fail in crowded scenes.We propose a novel hybrid system that is computationally efficient,robust to degraded video quality and able to filter out irrelevant individuals,making it suitable for real-life use.The system leverages multi-modal handcrafted features for interaction representation and a deep learning classifier for capturing complex dependencies.Using Mask R-CNN and YOLO11-Pose,we extract grayscale silhouettes and keypoint coordinates of interacting individuals,while filtering out irrelevant individuals using a proposed algorithm.From these,we extract silhouette-based features(local ternary pattern and histogram of optical flow)and keypoint-based features(distances,angles and velocities)that capture distinct spatial and temporal information.A Bidirectional Long Short-Term Memory network(BiLSTM)then classifies the interactions.Extensive experiments on the UT Interaction,SBU Kinect Interaction and the ISR-UOL 3D social activity datasets demonstrate that our system achieves competitive accuracy.They also validate the effectiveness of the chosen features and classifier,along with the proposed system’s computational efficiency and robustness to occlusion.展开更多
Three monomers,namely A2,B2,and GH,were designed and synthesized.By utilizing double host-vip interactions,the monomers A2+B2+GH underwent self-assembly to form a supramolecular linear polymer(SLP)at high concentrat...Three monomers,namely A2,B2,and GH,were designed and synthesized.By utilizing double host-vip interactions,the monomers A2+B2+GH underwent self-assembly to form a supramolecular linear polymer(SLP)at high concentrations.Long fibers could be pulled from the concentrated SLP solution.Upon the addition of PdCl_(2)(PhCN)_(2)into the SLP solution,a structural transformation occurred from SLP to a supramolecular crosslinked polymer(SCP)through metal coordination interaction.This transformation induced fluorescence quenching,test paper strips for ion detection experiment confirmed that the SLP had good detection ability for Pd^(2+).Furthermore,the SCP underwent a transformation into a gel when the concentration exceeded 145 mmol/L.The SCP gel demonstrated sensitivity to different stimuli,such as K^(+)ions and changes in temperature,accompanied by a reversible transition between sol and gel states.Additionally,rheological analyses indicated that the gel possessed favorable self-healing properties.展开更多
Solvothermal reactions of 4,4＇-oxybis（benzoic acid） （H2oba） with 1,3-dipyridyl benzene （1,3-dpb） produced a two-dimensional （2D） cadmium（Ⅱ） coordination polymer {[Cd（oba）（dpb）]·H2O}n （1）. The co...Solvothermal reactions of 4,4＇-oxybis（benzoic acid） （H2oba） with 1,3-dipyridyl benzene （1,3-dpb） produced a two-dimensional （2D） cadmium（Ⅱ） coordination polymer {[Cd（oba）（dpb）]·H2O}n （1）. The complex was characterized by elemental analysis, IR spectroscopy, and X-ray single-crystal diffraction. It crystallizes in the monoclinic system, space group C2/c with a = 13.6692（9）, b = 25.9647（17）, c = 8.7912（6） , α = 125.0370（10）, γ = 2544.7（3）°, V = 2544.7（3） 3, C30H22N2O6Cd, Mr = 618.91, Dc =1.609 g/cm3, F（000） = 1248, μ = 0.904 mm-1 and Z = 4. The neighboring Cd（Ⅱ） ions are linked by oba2-anions and 1,3-dpb to form an infinitely 2D wavelike sheet, and two such 2D sheets are interlocked with each other by H-bonding to form a 2D → 2D structure. The adjacent two groups of interlocked structures are further linked to form a bilayer 2D supramolecular network by π-π interactions. In addition, the fluorescence property of 1 was also studied.展开更多
The assembly reactions of o- （or m-, or p-） tetrafluorobenzenedicarboxylic acid （denoted as o-H2L, m-H2L and p-HzL, respectively）, benzonitrile and Ag＋ ion led to three compounds： [Ag2（PhCN）2（o-HL）2]n （1）,...The assembly reactions of o- （or m-, or p-） tetrafluorobenzenedicarboxylic acid （denoted as o-H2L, m-H2L and p-HzL, respectively）, benzonitrile and Ag＋ ion led to three compounds： [Ag2（PhCN）2（o-HL）2]n （1）, [Ag2（PhCN）2（m-HL）2]n （2） and [Ag2（PhCN）2（p-L）], （3）. 1 and 2 feature a 1D coordination chain, while 3 bears a 2D net structure. A variety of weak interactions are observed in the compounds. Strong nwrinteractions connect the 1D chains into a 3D supramolecular network in 1. Hydrogen bonds connect the chains into layers in 2. Three types of interesting π-π interactions also assemble the 2D layers into a 3D overall structure in 3.展开更多
Nickel-rich layered oxide LiNi_(1-x-y)Co_(x)Al_yO_(2)(NCA) with high theoretical capacity is a promising cathode material for the next-generation high-energy batteries.However,it undergoes a rapid capacity fading when...Nickel-rich layered oxide LiNi_(1-x-y)Co_(x)Al_yO_(2)(NCA) with high theoretical capacity is a promising cathode material for the next-generation high-energy batteries.However,it undergoes a rapid capacity fading when operating at high temperature due to the accelerated cathode/electrolyte interfacial reactions and adhesive efficacy loss of conventional polyvinylideneffuoride(PVdF) binder.Herein,poly(acrylonitrile-co-methyl acrylate) copolymer is designed with electron-rich-C≡N groups as a novel binder for LiNi_(0.8)Co_(0.1)Al_(0.1)O_(2) cathode at high temperature.The electron-rich-C≡N groups are able to coordinate with the active Ni^(3+) on the surface of NCA,alleviating electrolyte decomposition and cathode structure degradation.Moreover,the strong adhesive ability is conducive to maintain integrity of electrodes upon cycling at 55℃.In consequence,the NCA electrodes with this functional binder display improved cycling stability(81.5% capacity retention after 100 cycles) and rate performance at 55℃.展开更多
The binding of Co (phen)2dppz3+ to calf thymus DNA,as investigated using absorption spectroscopy. viscosity and electrophoresis measurements,here dppz is dipyrido[3, 2-a: 2'3'-c]phenazine. The compound shows a...The binding of Co (phen)2dppz3+ to calf thymus DNA,as investigated using absorption spectroscopy. viscosity and electrophoresis measurements,here dppz is dipyrido[3, 2-a: 2'3'-c]phenazine. The compound shows absorption hypochromicity and the specific viscosity increased upon binding to calf thymus DNA The complex is also shown to be more efficient photosensitisers for single strand breaks in plasmid DNA展开更多
Catalysts with asymmetric coordination exhibit excellent electrocatalytic activity due to changes in the active sites,which affect the arrangement of reactants and catalytic activity/selectivity.Hence,the exploration ...Catalysts with asymmetric coordination exhibit excellent electrocatalytic activity due to changes in the active sites,which affect the arrangement of reactants and catalytic activity/selectivity.Hence,the exploration of the inherent characteristics of active sites within diverse coordination environments holds great significance for the experimental design of catalytic structures.Single-atom catalysts(SACs)characterized by high coordination with four carbons(26 candidates)and low coordination with dinitrogen(27candidates)are constructed using nitrogen-doped graphdiyne derivatives(NGDY)as the substrate.Additionally,5 species of dual-atom catalysts(DACs)with coexistence of both high and low coordination sites are also developed and their nitrogen reduction reaction(NRR)activities are systematically investigated by density functional theory.The results indicate that metals with low coordination exhibit superior catalytic performance,such as Mo^(L)-NGDY(U_(L)=-0.30 V)and Nb^(L)-NGDY(U_(L)=-0.32 V).Furthermore,machine learning(ML)methods have deeply analyzed and elucidated the primary intrinsic characteristics that influence catalytic performance.These results not only unveil the underlying mechanisms behind the exceptional catalytic performance exhibited by low-coordination metal atoms,but also provide relevant and significant descriptors.More importantly,based on an investigation of the catalytic activity of a series of DACs,the“buffer and low-coordination accumulate”asymmetric coordination mechanism is proposed to unveil the long-range interactions between low and high coordination atoms.Due to this remote communication,MoNb-NGDY(U_(L)=-0.09/-0.37 V)exhibits the best NRR activity.This mechanism provides valuable insights into the origin of long-range bipartite interactions and inspires the design and synthesis of NRR catalysts with different coordination environments.展开更多
This study reveals that the noncovalent complexation betweenβ-CD and Cu（HMTA）^（2＋） makes a positive contribution to the coordination interaction between Cu^（2＋） and HMTA in a tricomponent system.Besides,mono-...This study reveals that the noncovalent complexation betweenβ-CD and Cu（HMTA）^（2＋） makes a positive contribution to the coordination interaction between Cu^（2＋） and HMTA in a tricomponent system.Besides,mono- and binuclear complexes：[β-CDCu]~＋ and[Cu·β-CDCu]~＋ were observed under the condition of ESI-MS.展开更多
A new metal-organic coordination polymer [Pb（mfpdc）（CH3OH）]n （1, mfpdc = 2,6-dimethyl-4-（2-furanyl） pyridine-3,5-dicarboxylate） was synthesized and characterized by single-crystal X-ray analyses. The crystal i...A new metal-organic coordination polymer [Pb（mfpdc）（CH3OH）]n （1, mfpdc = 2,6-dimethyl-4-（2-furanyl） pyridine-3,5-dicarboxylate） was synthesized and characterized by single-crystal X-ray analyses. The crystal is orthorhombic, space group Pbca, a = 15.6297（18）, b = 9.4803（11）, c = 18.598（2） A, V= 2755.8（6） A3, Z = 8, Mr= 498.44, Dc= 2.403 Mg/m3, F（000） = 1872, the final R = 0.0275 and wR = 0.0726 （1 〉 2σ（I））. There are interesting polynuclear zigzag （PbOs）n chains in the structure of 1, and there have interesting axially chiral S- and R-unit Pb4L units constructed from prochiral organic ligands through C-H...O bonding. The （R/S）-Pb4L units by sharing Pb centers generate a 2-D coordination network, in which there exist rare n65Pb （3.2610 A） interactions. The solid-state photoluminescent emission of compound 1 appears at 487 nm.展开更多
Recently,numerous mechanically robust synthetic hydrogels have been created.However,unlike natural loading-bearing materials such as cartilages and muscles,most hydrogels have inherently contradictory requirements,obs...Recently,numerous mechanically robust synthetic hydrogels have been created.However,unlike natural loading-bearing materials such as cartilages and muscles,most hydrogels have inherently contradictory requirements,obstructing the design of hydrogels with characteristics of robustness and rapid self-recoverability.Herein,we present a facile strategy for constructing mechanically robust and rapidly self-recoverable hydrogels.The linear poly(acrylamide-co-itaconic acid)chains crosslink via coordination bonds and minimal chemical crosslinkers to form the hydrogel network.Such design endows the coordination interactions to be asymmetrically distributed.Under deformation,the coordination interactions exhibit a reversible dissociation-and-reorganization property,demonstrating a new mechanism for energy dissipation and stress redistribution.Thus,the hydrogels possess tensile strength up to 12.5 MPa and toughness up to 28.2 MJ/m3.Moreover,the inherent dynamic nature of the coordination bonds imparts these hydrogels with stretch rate-and temperature-dependent mechanical behavior as well as excellent self-recovery performance.The method employed in this study is universal and is applicable to other polymers with load-bearing yet rapid recovery conditions.This study will facilitate diverse applications of most metallosupramolecular hydrogels.展开更多
Interaction is one of the crucial features of multl-agent systems, in which there are two kinds of interaction： agent-to-agent and human-to-agent. In order to unify the two kinds of interaction while designing multi-...Interaction is one of the crucial features of multl-agent systems, in which there are two kinds of interaction： agent-to-agent and human-to-agent. In order to unify the two kinds of interaction while designing multi-agent systems, this paper introduces Q language-a scenario description language for designing interaction among agents and humans. Based on Q, we propose an integrating interaction framework system for multi-agent coordination, in which Q scenarios are used to uniformly describe both kinds of interactions. Being in accordance to the characteristics of Q language, the Q-based framework makes the interaction process open and easily understood by the users. Additionally, it makes specific applications of multi-agent systems easy to be established by application designers. By applying agent negotiation in agent-mediated e-commerce and agent cooperation in interoperable information query on the Semantic Web, we illustrate how the presented framework for multi-agent coordination is implemented in concrete applications. At the same time, these two different applications also demonstrate usability of the presented framework and verify validity of Q language.展开更多
Surface waves comprise an important aspect of the interaction between the atmosphere and the ocean, so a dynamically consistent framework for modelling atmosphere-ocean interaction must take account of surface waves, ...Surface waves comprise an important aspect of the interaction between the atmosphere and the ocean, so a dynamically consistent framework for modelling atmosphere-ocean interaction must take account of surface waves, either implicitly or explicitly. In order to calculate the effect of wind forcing on waves and currents, and vice versa, it is necessary to employ a consistent formula- tion of the energy and momentum balance within the airflow, wave field, and water column. It is very advantageous to apply sur- face-following coordinate systems, whereby the steep gradients in mean flow properties near the air-water interface in the cross-interface direction may be resolved over distances which are much smaller than the height of the waves themselves. We may account for the waves explicitly by employing a numerical spectral wave model, and applying a suitable theory of wave–mean flow interaction. If the mean flow is small compared with the wave phase speed, perturbation expansions of the hydrodynamic equations in a Lagrangian or generalized Lagrangian mean framework are useful: for stronger flows, such as for wind blowing over waves, the presence of critical levels where the mean flow velocity is equal to the wave phase speed necessitates the application of more general types of surface-following coordinate system. The interaction of the flow of air and water and associated differences in temperature and the concentration of various substances (such as gas species) gives rise to a complex boundary-layer structure at a wide range of vertical scales, from the sub-millimetre scales of gaseous diffusion, to several tens of metres for the turbulent Ekman layer. The bal- ance of momentum, heat, and mass is also affected significantly by breaking waves, which act to increase the effective area of the surface for mass transfer, and increase turbulent diffusive fluxes via the conversion of wave energy to turbulent kinetic energy.展开更多
China is a country with a long history of agricultural development,the tr adition of bureaucratic administra-tion and economic management system s for the social development.In its t ransition from traditional society...China is a country with a long history of agricultural development,the tr adition of bureaucratic administra-tion and economic management system s for the social development.In its t ransition from traditional society to modern soci-ety during the past 50years,the rela tions between rural areas and urban a reas have been kept abnormal if considered from the point of view of the modernized co untries.Today,China still has its more than 70percent of population,bu t limited capital,lower technology and underdeveloped culture,in the rural areas.This unbalance forms not only the o bstacles to China’s modernization of social development,but also the barriers to th e society,economy and environment sustainable devel-opment.This paper focuses on the dis cussion about the coordinate develo pment of the relations between rural and urban in the past 50years,and the authors hold that only has the abnormal relation between the two areas been corrected,could China’s future development of natio nal economy be successful.展开更多
Protected areas have a double mandate of both "protection" and "use." Naturebased tourism is considered an effective tool in terms of environmental conservation. Understanding the causes and conseq...Protected areas have a double mandate of both "protection" and "use." Naturebased tourism is considered an effective tool in terms of environmental conservation. Understanding the causes and consequences of a spatiotemporal succession of tourism construction is an important channel to explore the changes of tourism-environment interaction in the protected area. To analyze the spatio-temporal variations in tourism construction lands, we adopted Mt. Bogda as an example. We systematically quantified the interaction between these changes and environmental variables and explored the evolution process of tourism-environment interaction of the mountainous protected area in the northwest arid region. Our results revealed the following:(1) In the Bogda protected area, the proportion of tourism construction lands first appeared to be increasing, then decreasing dramatically, and finally growing slowly. The spatial expansion of tourism construction lands followed the "core-periphery" pattern, respectively showing shapely infilling, reasonable agglomeration, barycenter shift, and outlying growth from 1990 to 2018 as the stages of concentrating on the core.(2) The higher land-use intensity of tourism construction drove the changes of landscape fragmentation, diversity, stability, primitive, and nature degree in the protected area. The coupling coordination between tourism and the environment in the Bogda area decreased at first, and then slowly increased. Meanwhile, tourism did not cause irreversible damage to the natural environment, and the coupling coordination degree between tourism and the environment was still in the state of balanced development. It expressed the states of original balanced, development exceeds environment and barely balanced, and superiorly balanced. The historical evolution of tourism-environment interaction in Bogda reflects the pattern of periodic changes in China’s protected areas to a certain extent.展开更多
Molecularly imprinted polymer, exhibiting considerable enantioselectivity for L-mandelic acid, was prepared using metal coordination-chelation interaction. By evaluating the recognition characteristics in the chromato...Molecularly imprinted polymer, exhibiting considerable enantioselectivity for L-mandelic acid, was prepared using metal coordination-chelation interaction. By evaluating the recognition characteristics in the chromatographic mode, the recognition interactions were proposed: specific and nonspecific metal coordination-chelation interaction and hydrophobic interaction were responsible for substrate binding on metal-complexing imprinted polymer; while the selective recognition only came from specific metal coordination-chelation interaction and specific hydrophobic interaction.展开更多
Inspired by Model Predictive Interaction Control(MPIC),this paper proposes differential models for estimating contact geometric parameters and normal-friction forces and formulates an optimal control problem with mult...Inspired by Model Predictive Interaction Control(MPIC),this paper proposes differential models for estimating contact geometric parameters and normal-friction forces and formulates an optimal control problem with multiple constraints to allow robots to perform rigid-soft heterogeneous contact tasks.Within the MPIC,robot dynamics are linearized,and Extended Kalman Filters are used for the online estimation of geometry-aware parameters.Meanwhile,a geometry-aware Hertz contact model is introduced for the online estimation of contact forces.We then implement the force-position coordinate optimization by incorporating the contact parameters and interaction force constraints into a gradient-based optimization MPC.Experimental validations were designed for two contact modes:“single-point contact”and“continuous contact”,involving materials with four different Young’s moduli and tested in human arm“relaxation-contraction”task.Results indicate that our framework ensures consistent geometry-aware parameter estimation and maintains reliable force interaction to guarantee safety.Our method reduces the maximum impact force by 50%and decreases the average force error by 42%.The proposed framework has potential applications in medical and industrial tasks involving the manipulation of rigid,soft,and deformable objects.展开更多
Economic growth and environmental pollution have become the bases of geopolitical competition due to the multiple constraints of growth in energy consumption and environmental protection in recent decades.Whether the ...Economic growth and environmental pollution have become the bases of geopolitical competition due to the multiple constraints of growth in energy consumption and environmental protection in recent decades.Whether the coordinated development of inward foreign direct investment(IFDI)and outward foreign direct investment(OFDI)promote economic growth while reducing environmental pollution and realizing high-quality development affects the overall socialist modernization under China’s“Dual Circulation”policy.Using China’s provincial panel data from 2005 to 2020,this paper first measured green total factor productivity(GTFP)and the coordinated development index(CDIFDI)of IFDI and OFDI via the slacks-based measureglobal Malmquist–Luenberger(SBM-GML)model and the capacity coupling model.A panel threshold model with interactive effects(PTIFEs)was then applied to explore the nonlinear impact of the CDIFDI on China’s GTFP.Finally,a regional heterogeneity analysis was conducted for China’s eastern,central and western regions of China.Results show that(1)GTFP in China kept rising with small fluctuations during the sample period,with the increasing range of GTFP decreasing from east to west.(2)CDIFDI had a significant“U”-shaped threshold effect on GTFP,and the main threshold variables were the industrial structure and the level of economic development.(3)CDIFDI played a positive role in promoting GTFP growth in the eastern region,while the effects of CDIFDI on GTFP in the central and western regions were not significant.Policy-makers and enterprises should comprehensively consider promoting regional industrial upgrading and economic growth to achieve a greater positive impact of CDIFDI on GTFP.Scientifically measuring GTFP and exploring the nonlinear impact of the CDIFDI on GTFP and regional heterogeneity provide helpful references for policy-makers to coordinate the high-quality development of regional economies.展开更多
Multi-site coupling is a promising strategy for developing highly efficient and CO-resistant hydrogen oxidation reaction(HOR)catalysts for proton exchange membrane fuel cells(PEMFCs).However,designing multifunctional ...Multi-site coupling is a promising strategy for developing highly efficient and CO-resistant hydrogen oxidation reaction(HOR)catalysts for proton exchange membrane fuel cells(PEMFCs).However,designing multifunctional synergistic schemes for single-atom sites remains a significant challenge.Herein,we propose a dual-template-confined oxophilic engineering strategy to construct well-dispersed iridium-nickel(IrNi)atomic dimers adjacent to IrNi nanoclusters on porous nitrogen-doped carbon(IrNi_(Dimer/NC1.8)-PNC).The paired IrNi dimer features an asymmetric Ir-N_(3)configuration coordinated with heteroatomic Ni-N_(3)O via an N-bridge.Remarkably,IrNi_(Dimer/NC1.8)-PNC exhibits a~23-fold enhancement in mass activity(4.36 A mg-1Ir at 20 mV)and 5-fold longer stability compared to benchmarking Pt/C toward HOR,while achieving a high rated power density of 1.18 W cm^(-2)in PEMFC anode applications.Furthermore,IrNi_(Dimer/NC1.8)-PNC demonstrates superior CO tolerance over monometallic Ir and Pt/C in both half-cell and full-cell devices.Combined experimental and density functional theory studies reveal that oxophilic Ni modulates the electronic environment of Ir through alloying and dimer interactions,thereby enhancing HOR activity.Importantly,the asymmetric IrNi dimer enables efficient CO^(*)and OH^(*)co-adsorption while facilitating CO_(2)^(*)desorption,synergistically mitigating CO poisoning and improving atom utilization efficiency.This work provides a design strategy and fundamental insights for multi-site synergistic catalysts in PEMFC anodes.展开更多
基金supported and funded by Princess Nourah bint Abdulrahman University Researchers Supporting Project number(PNURSP2025R410),Princess Nourah bint Abdulrahman University,Riyadh,Saudi Arabia.
文摘Recognizing human interactions in RGB videos is a critical task in computer vision,with applications in video surveillance.Existing deep learning-based architectures have achieved strong results,but are computationally intensive,sensitive to video resolution changes and often fail in crowded scenes.We propose a novel hybrid system that is computationally efficient,robust to degraded video quality and able to filter out irrelevant individuals,making it suitable for real-life use.The system leverages multi-modal handcrafted features for interaction representation and a deep learning classifier for capturing complex dependencies.Using Mask R-CNN and YOLO11-Pose,we extract grayscale silhouettes and keypoint coordinates of interacting individuals,while filtering out irrelevant individuals using a proposed algorithm.From these,we extract silhouette-based features(local ternary pattern and histogram of optical flow)and keypoint-based features(distances,angles and velocities)that capture distinct spatial and temporal information.A Bidirectional Long Short-Term Memory network(BiLSTM)then classifies the interactions.Extensive experiments on the UT Interaction,SBU Kinect Interaction and the ISR-UOL 3D social activity datasets demonstrate that our system achieves competitive accuracy.They also validate the effectiveness of the chosen features and classifier,along with the proposed system’s computational efficiency and robustness to occlusion.
基金supported by the National Natural Science Foundation of China(Nos.22161020,22022107,21801100)the Natural Science Foundation of Jiangxi Province(No.20212BAB203014)the Program of Qingjiang Excellent Young Talents,Jiangxi University of Science and Technology。
文摘Three monomers,namely A2,B2,and GH,were designed and synthesized.By utilizing double host-vip interactions,the monomers A2+B2+GH underwent self-assembly to form a supramolecular linear polymer(SLP)at high concentrations.Long fibers could be pulled from the concentrated SLP solution.Upon the addition of PdCl_(2)(PhCN)_(2)into the SLP solution,a structural transformation occurred from SLP to a supramolecular crosslinked polymer(SCP)through metal coordination interaction.This transformation induced fluorescence quenching,test paper strips for ion detection experiment confirmed that the SLP had good detection ability for Pd^(2+).Furthermore,the SCP underwent a transformation into a gel when the concentration exceeded 145 mmol/L.The SCP gel demonstrated sensitivity to different stimuli,such as K^(+)ions and changes in temperature,accompanied by a reversible transition between sol and gel states.Additionally,rheological analyses indicated that the gel possessed favorable self-healing properties.
基金supported by the National Natural Science Foundation of China (21071004, 51173002)the Start-up Foundation and the young teacher’s research foundation of Anhui University of Science and Technology (11227, 2012QNZ08)the Research fund of Key Laboratory for Advanced Technology in Environmental Protection of Jiangsu Province (AE 201107)
文摘Solvothermal reactions of 4,4＇-oxybis（benzoic acid） （H2oba） with 1,3-dipyridyl benzene （1,3-dpb） produced a two-dimensional （2D） cadmium（Ⅱ） coordination polymer {[Cd（oba）（dpb）]·H2O}n （1）. The complex was characterized by elemental analysis, IR spectroscopy, and X-ray single-crystal diffraction. It crystallizes in the monoclinic system, space group C2/c with a = 13.6692（9）, b = 25.9647（17）, c = 8.7912（6） , α = 125.0370（10）, γ = 2544.7（3）°, V = 2544.7（3） 3, C30H22N2O6Cd, Mr = 618.91, Dc =1.609 g/cm3, F（000） = 1248, μ = 0.904 mm-1 and Z = 4. The neighboring Cd（Ⅱ） ions are linked by oba2-anions and 1,3-dpb to form an infinitely 2D wavelike sheet, and two such 2D sheets are interlocked with each other by H-bonding to form a 2D → 2D structure. The adjacent two groups of interlocked structures are further linked to form a bilayer 2D supramolecular network by π-π interactions. In addition, the fluorescence property of 1 was also studied.
基金Supported by the NNSFC (21071025,91122031, 21107008)Doctoral Fund of Ministry of Education of China (20100041120021)the Fundamental Research Funds for the Central Universities (DUT12YQ04)
文摘The assembly reactions of o- （or m-, or p-） tetrafluorobenzenedicarboxylic acid （denoted as o-H2L, m-H2L and p-HzL, respectively）, benzonitrile and Ag＋ ion led to three compounds： [Ag2（PhCN）2（o-HL）2]n （1）, [Ag2（PhCN）2（m-HL）2]n （2） and [Ag2（PhCN）2（p-L）], （3）. 1 and 2 feature a 1D coordination chain, while 3 bears a 2D net structure. A variety of weak interactions are observed in the compounds. Strong nwrinteractions connect the 1D chains into a 3D supramolecular network in 1. Hydrogen bonds connect the chains into layers in 2. Three types of interesting π-π interactions also assemble the 2D layers into a 3D overall structure in 3.
基金supported by the National Natural Science Foundation of China (No. 21875181)the Natural Science Basic Research Program of Shaanxi (Program No. 2019JLP-13)+1 种基金the Shaanxi Key Research and Development Project (No. 2019TSLGY07-05)the 111 Project 2.0 (BP2018008)。
文摘Nickel-rich layered oxide LiNi_(1-x-y)Co_(x)Al_yO_(2)(NCA) with high theoretical capacity is a promising cathode material for the next-generation high-energy batteries.However,it undergoes a rapid capacity fading when operating at high temperature due to the accelerated cathode/electrolyte interfacial reactions and adhesive efficacy loss of conventional polyvinylideneffuoride(PVdF) binder.Herein,poly(acrylonitrile-co-methyl acrylate) copolymer is designed with electron-rich-C≡N groups as a novel binder for LiNi_(0.8)Co_(0.1)Al_(0.1)O_(2) cathode at high temperature.The electron-rich-C≡N groups are able to coordinate with the active Ni^(3+) on the surface of NCA,alleviating electrolyte decomposition and cathode structure degradation.Moreover,the strong adhesive ability is conducive to maintain integrity of electrodes upon cycling at 55℃.In consequence,the NCA electrodes with this functional binder display improved cycling stability(81.5% capacity retention after 100 cycles) and rate performance at 55℃.
文摘The binding of Co (phen)2dppz3+ to calf thymus DNA,as investigated using absorption spectroscopy. viscosity and electrophoresis measurements,here dppz is dipyrido[3, 2-a: 2'3'-c]phenazine. The compound shows absorption hypochromicity and the specific viscosity increased upon binding to calf thymus DNA The complex is also shown to be more efficient photosensitisers for single strand breaks in plasmid DNA
基金supports by the National Natural Science Foundation of China(NSFC,Grant No.52271113)the Natural Science Foundation of Shaanxi Province,China(2020JM 218)the Fundamental Research Funds for the Central Universities(CHD300102311405)。
文摘Catalysts with asymmetric coordination exhibit excellent electrocatalytic activity due to changes in the active sites,which affect the arrangement of reactants and catalytic activity/selectivity.Hence,the exploration of the inherent characteristics of active sites within diverse coordination environments holds great significance for the experimental design of catalytic structures.Single-atom catalysts(SACs)characterized by high coordination with four carbons(26 candidates)and low coordination with dinitrogen(27candidates)are constructed using nitrogen-doped graphdiyne derivatives(NGDY)as the substrate.Additionally,5 species of dual-atom catalysts(DACs)with coexistence of both high and low coordination sites are also developed and their nitrogen reduction reaction(NRR)activities are systematically investigated by density functional theory.The results indicate that metals with low coordination exhibit superior catalytic performance,such as Mo^(L)-NGDY(U_(L)=-0.30 V)and Nb^(L)-NGDY(U_(L)=-0.32 V).Furthermore,machine learning(ML)methods have deeply analyzed and elucidated the primary intrinsic characteristics that influence catalytic performance.These results not only unveil the underlying mechanisms behind the exceptional catalytic performance exhibited by low-coordination metal atoms,but also provide relevant and significant descriptors.More importantly,based on an investigation of the catalytic activity of a series of DACs,the“buffer and low-coordination accumulate”asymmetric coordination mechanism is proposed to unveil the long-range interactions between low and high coordination atoms.Due to this remote communication,MoNb-NGDY(U_(L)=-0.09/-0.37 V)exhibits the best NRR activity.This mechanism provides valuable insights into the origin of long-range bipartite interactions and inspires the design and synthesis of NRR catalysts with different coordination environments.
文摘This study reveals that the noncovalent complexation betweenβ-CD and Cu（HMTA）^（2＋） makes a positive contribution to the coordination interaction between Cu^（2＋） and HMTA in a tricomponent system.Besides,mono- and binuclear complexes：[β-CDCu]~＋ and[Cu·β-CDCu]~＋ were observed under the condition of ESI-MS.
基金supported by Science and Technology Projects of Chongqing Municipal Education Commission(No.KJ100602)Chongqing Normal University Scientific Research Foundation Project(Nos.10XLZ005and2011XLS30)
文摘A new metal-organic coordination polymer [Pb（mfpdc）（CH3OH）]n （1, mfpdc = 2,6-dimethyl-4-（2-furanyl） pyridine-3,5-dicarboxylate） was synthesized and characterized by single-crystal X-ray analyses. The crystal is orthorhombic, space group Pbca, a = 15.6297（18）, b = 9.4803（11）, c = 18.598（2） A, V= 2755.8（6） A3, Z = 8, Mr= 498.44, Dc= 2.403 Mg/m3, F（000） = 1872, the final R = 0.0275 and wR = 0.0726 （1 〉 2σ（I））. There are interesting polynuclear zigzag （PbOs）n chains in the structure of 1, and there have interesting axially chiral S- and R-unit Pb4L units constructed from prochiral organic ligands through C-H...O bonding. The （R/S）-Pb4L units by sharing Pb centers generate a 2-D coordination network, in which there exist rare n65Pb （3.2610 A） interactions. The solid-state photoluminescent emission of compound 1 appears at 487 nm.
基金National Natural Science Foundation of China(No.51873110).
文摘Recently,numerous mechanically robust synthetic hydrogels have been created.However,unlike natural loading-bearing materials such as cartilages and muscles,most hydrogels have inherently contradictory requirements,obstructing the design of hydrogels with characteristics of robustness and rapid self-recoverability.Herein,we present a facile strategy for constructing mechanically robust and rapidly self-recoverable hydrogels.The linear poly(acrylamide-co-itaconic acid)chains crosslink via coordination bonds and minimal chemical crosslinkers to form the hydrogel network.Such design endows the coordination interactions to be asymmetrically distributed.Under deformation,the coordination interactions exhibit a reversible dissociation-and-reorganization property,demonstrating a new mechanism for energy dissipation and stress redistribution.Thus,the hydrogels possess tensile strength up to 12.5 MPa and toughness up to 28.2 MJ/m3.Moreover,the inherent dynamic nature of the coordination bonds imparts these hydrogels with stretch rate-and temperature-dependent mechanical behavior as well as excellent self-recovery performance.The method employed in this study is universal and is applicable to other polymers with load-bearing yet rapid recovery conditions.This study will facilitate diverse applications of most metallosupramolecular hydrogels.
文摘Interaction is one of the crucial features of multl-agent systems, in which there are two kinds of interaction： agent-to-agent and human-to-agent. In order to unify the two kinds of interaction while designing multi-agent systems, this paper introduces Q language-a scenario description language for designing interaction among agents and humans. Based on Q, we propose an integrating interaction framework system for multi-agent coordination, in which Q scenarios are used to uniformly describe both kinds of interactions. Being in accordance to the characteristics of Q language, the Q-based framework makes the interaction process open and easily understood by the users. Additionally, it makes specific applications of multi-agent systems easy to be established by application designers. By applying agent negotiation in agent-mediated e-commerce and agent cooperation in interoperable information query on the Semantic Web, we illustrate how the presented framework for multi-agent coordination is implemented in concrete applications. At the same time, these two different applications also demonstrate usability of the presented framework and verify validity of Q language.
文摘Surface waves comprise an important aspect of the interaction between the atmosphere and the ocean, so a dynamically consistent framework for modelling atmosphere-ocean interaction must take account of surface waves, either implicitly or explicitly. In order to calculate the effect of wind forcing on waves and currents, and vice versa, it is necessary to employ a consistent formula- tion of the energy and momentum balance within the airflow, wave field, and water column. It is very advantageous to apply sur- face-following coordinate systems, whereby the steep gradients in mean flow properties near the air-water interface in the cross-interface direction may be resolved over distances which are much smaller than the height of the waves themselves. We may account for the waves explicitly by employing a numerical spectral wave model, and applying a suitable theory of wave–mean flow interaction. If the mean flow is small compared with the wave phase speed, perturbation expansions of the hydrodynamic equations in a Lagrangian or generalized Lagrangian mean framework are useful: for stronger flows, such as for wind blowing over waves, the presence of critical levels where the mean flow velocity is equal to the wave phase speed necessitates the application of more general types of surface-following coordinate system. The interaction of the flow of air and water and associated differences in temperature and the concentration of various substances (such as gas species) gives rise to a complex boundary-layer structure at a wide range of vertical scales, from the sub-millimetre scales of gaseous diffusion, to several tens of metres for the turbulent Ekman layer. The bal- ance of momentum, heat, and mass is also affected significantly by breaking waves, which act to increase the effective area of the surface for mass transfer, and increase turbulent diffusive fluxes via the conversion of wave energy to turbulent kinetic energy.
文摘China is a country with a long history of agricultural development,the tr adition of bureaucratic administra-tion and economic management system s for the social development.In its t ransition from traditional society to modern soci-ety during the past 50years,the rela tions between rural areas and urban a reas have been kept abnormal if considered from the point of view of the modernized co untries.Today,China still has its more than 70percent of population,bu t limited capital,lower technology and underdeveloped culture,in the rural areas.This unbalance forms not only the o bstacles to China’s modernization of social development,but also the barriers to th e society,economy and environment sustainable devel-opment.This paper focuses on the dis cussion about the coordinate develo pment of the relations between rural and urban in the past 50years,and the authors hold that only has the abnormal relation between the two areas been corrected,could China’s future development of natio nal economy be successful.
基金National Natural Science Foundation of China,No.41971192。
文摘Protected areas have a double mandate of both "protection" and "use." Naturebased tourism is considered an effective tool in terms of environmental conservation. Understanding the causes and consequences of a spatiotemporal succession of tourism construction is an important channel to explore the changes of tourism-environment interaction in the protected area. To analyze the spatio-temporal variations in tourism construction lands, we adopted Mt. Bogda as an example. We systematically quantified the interaction between these changes and environmental variables and explored the evolution process of tourism-environment interaction of the mountainous protected area in the northwest arid region. Our results revealed the following:(1) In the Bogda protected area, the proportion of tourism construction lands first appeared to be increasing, then decreasing dramatically, and finally growing slowly. The spatial expansion of tourism construction lands followed the "core-periphery" pattern, respectively showing shapely infilling, reasonable agglomeration, barycenter shift, and outlying growth from 1990 to 2018 as the stages of concentrating on the core.(2) The higher land-use intensity of tourism construction drove the changes of landscape fragmentation, diversity, stability, primitive, and nature degree in the protected area. The coupling coordination between tourism and the environment in the Bogda area decreased at first, and then slowly increased. Meanwhile, tourism did not cause irreversible damage to the natural environment, and the coupling coordination degree between tourism and the environment was still in the state of balanced development. It expressed the states of original balanced, development exceeds environment and barely balanced, and superiorly balanced. The historical evolution of tourism-environment interaction in Bogda reflects the pattern of periodic changes in China’s protected areas to a certain extent.
文摘Molecularly imprinted polymer, exhibiting considerable enantioselectivity for L-mandelic acid, was prepared using metal coordination-chelation interaction. By evaluating the recognition characteristics in the chromatographic mode, the recognition interactions were proposed: specific and nonspecific metal coordination-chelation interaction and hydrophobic interaction were responsible for substrate binding on metal-complexing imprinted polymer; while the selective recognition only came from specific metal coordination-chelation interaction and specific hydrophobic interaction.
基金supported in part by the National Natural Science Foundation of China(62203126)the Science and Technology Plan Project of Guangdong Province(2023A0505010014)+1 种基金the Innovation and Technology Commission of the HKSAR Government under the InnoHK Initiative,and in part by the Key Areas R&D Program of Dongguan City(20201200300062)the GDAS’Project of Science and Technology Development(2022GDASZH-2022010108).
文摘Inspired by Model Predictive Interaction Control(MPIC),this paper proposes differential models for estimating contact geometric parameters and normal-friction forces and formulates an optimal control problem with multiple constraints to allow robots to perform rigid-soft heterogeneous contact tasks.Within the MPIC,robot dynamics are linearized,and Extended Kalman Filters are used for the online estimation of geometry-aware parameters.Meanwhile,a geometry-aware Hertz contact model is introduced for the online estimation of contact forces.We then implement the force-position coordinate optimization by incorporating the contact parameters and interaction force constraints into a gradient-based optimization MPC.Experimental validations were designed for two contact modes:“single-point contact”and“continuous contact”,involving materials with four different Young’s moduli and tested in human arm“relaxation-contraction”task.Results indicate that our framework ensures consistent geometry-aware parameter estimation and maintains reliable force interaction to guarantee safety.Our method reduces the maximum impact force by 50%and decreases the average force error by 42%.The proposed framework has potential applications in medical and industrial tasks involving the manipulation of rigid,soft,and deformable objects.
基金supported by the Key Project of National Philosophy and Social Science Foundation of China(Grant No.24AGL007).
文摘Economic growth and environmental pollution have become the bases of geopolitical competition due to the multiple constraints of growth in energy consumption and environmental protection in recent decades.Whether the coordinated development of inward foreign direct investment(IFDI)and outward foreign direct investment(OFDI)promote economic growth while reducing environmental pollution and realizing high-quality development affects the overall socialist modernization under China’s“Dual Circulation”policy.Using China’s provincial panel data from 2005 to 2020,this paper first measured green total factor productivity(GTFP)and the coordinated development index(CDIFDI)of IFDI and OFDI via the slacks-based measureglobal Malmquist–Luenberger(SBM-GML)model and the capacity coupling model.A panel threshold model with interactive effects(PTIFEs)was then applied to explore the nonlinear impact of the CDIFDI on China’s GTFP.Finally,a regional heterogeneity analysis was conducted for China’s eastern,central and western regions of China.Results show that(1)GTFP in China kept rising with small fluctuations during the sample period,with the increasing range of GTFP decreasing from east to west.(2)CDIFDI had a significant“U”-shaped threshold effect on GTFP,and the main threshold variables were the industrial structure and the level of economic development.(3)CDIFDI played a positive role in promoting GTFP growth in the eastern region,while the effects of CDIFDI on GTFP in the central and western regions were not significant.Policy-makers and enterprises should comprehensively consider promoting regional industrial upgrading and economic growth to achieve a greater positive impact of CDIFDI on GTFP.Scientifically measuring GTFP and exploring the nonlinear impact of the CDIFDI on GTFP and regional heterogeneity provide helpful references for policy-makers to coordinate the high-quality development of regional economies.
基金supported by the National Natural Science Foundation of China(22279079 and 22472101)Guangdong Science and Technology Department Program(2021QN02L252,2023A1515010021,and 2024A1515011543)Research Team Cultivation Program of Shenzhen University(2023QNT007)。
文摘Multi-site coupling is a promising strategy for developing highly efficient and CO-resistant hydrogen oxidation reaction(HOR)catalysts for proton exchange membrane fuel cells(PEMFCs).However,designing multifunctional synergistic schemes for single-atom sites remains a significant challenge.Herein,we propose a dual-template-confined oxophilic engineering strategy to construct well-dispersed iridium-nickel(IrNi)atomic dimers adjacent to IrNi nanoclusters on porous nitrogen-doped carbon(IrNi_(Dimer/NC1.8)-PNC).The paired IrNi dimer features an asymmetric Ir-N_(3)configuration coordinated with heteroatomic Ni-N_(3)O via an N-bridge.Remarkably,IrNi_(Dimer/NC1.8)-PNC exhibits a~23-fold enhancement in mass activity(4.36 A mg-1Ir at 20 mV)and 5-fold longer stability compared to benchmarking Pt/C toward HOR,while achieving a high rated power density of 1.18 W cm^(-2)in PEMFC anode applications.Furthermore,IrNi_(Dimer/NC1.8)-PNC demonstrates superior CO tolerance over monometallic Ir and Pt/C in both half-cell and full-cell devices.Combined experimental and density functional theory studies reveal that oxophilic Ni modulates the electronic environment of Ir through alloying and dimer interactions,thereby enhancing HOR activity.Importantly,the asymmetric IrNi dimer enables efficient CO^(*)and OH^(*)co-adsorption while facilitating CO_(2)^(*)desorption,synergistically mitigating CO poisoning and improving atom utilization efficiency.This work provides a design strategy and fundamental insights for multi-site synergistic catalysts in PEMFC anodes.
