The ionothermal reaction between CuCl_(2),1,4-bis(1,2,4-triazol-1-ylmethyl)benzene(BBTZ),and(NH_(4))_(6)Mo_(7)O_(24) in 1-ethyl-3-methylimidazolium bromide((Emim)Br)led to a new octamolybdate-based coordination polyme...The ionothermal reaction between CuCl_(2),1,4-bis(1,2,4-triazol-1-ylmethyl)benzene(BBTZ),and(NH_(4))_(6)Mo_(7)O_(24) in 1-ethyl-3-methylimidazolium bromide((Emim)Br)led to a new octamolybdate-based coordination polymer(Emim)2[Cu(BBTZ)_(2)(β-Mo_(8)O_(26))](Mo_(8)-CP).Mo_(8)-CP was characterized by elemental analysis,thermogravime-try,IR,powder X-ray diffraction,and single-crystal X-ray diffraction.In Mo_(8)-CP,structural analysis reveals that Cu coordinates with BBTZ ligands to form an interlocked 1D chain.These chains are further bridged by(β-Mo_(8)O_(26))^(4-)to construct a 3D coordination polymer.Notably,(Emim)^(+)acts as a structure-directing agent,occupying the channels of the 3D coordination polymer.Based on this unique structure,the ion exchange properties of Mo_(8)-CP toward rare-earth ions were investigated.It has been found that the luminescent color of the material can be successfully regulat-ed by introducing Eu^(3+)or Tb^(3+)through ion exchange.CCDC:2475110,Mo_(8)-CP.展开更多
Circumferentially non-uniform tip clearances induced by rotor eccentricity significantly affect the overall performance of axial compressors,particularly the stability margin.Currently,Computational Fluid Dynamics(CFD...Circumferentially non-uniform tip clearances induced by rotor eccentricity significantly affect the overall performance of axial compressors,particularly the stability margin.Currently,Computational Fluid Dynamics(CFD)plays a crucial role in the aerodynamic analysis of eccentric compressors.However,conventional full-annulus Unsteady Reynolds-Averaged Navier-Stokes(URANS)simulations are prohibitively expensive for routine design and analysis purposes.To address this issue,the paper presents a novel Fourier-based method,called the Time-Space Collocation(TSC)method,for efficient simulations of eccentric compressors.This method coherently treats temporal and spatial harmonics,making it well-suited to tackle the rotor eccentricity problem,as the perturbation waves induced by eccentricity are time-periodic with respect to the rotor and space-periodic with respect to the stator.Three numerical cases,including NASA Rotor 67,original Stage 67,and Stage 67 with a reduced rotor-stator axial gap,were conducted to verify the effectiveness of the TSC method.The results indicate that,for the rotor eccentricity levels studied in this paper,the influence of weak rotor-stator interactions can be disregarded in the original Stage 67.In this situation,applying three harmonics can accurately capture both the performance variations and the non-uniformly distributed flowfields of eccentric compressors,while achieving a reduction in run time by two orders of magnitude compared to full-annulus URANS simulations.However,in Stage 67 with a reduced rotor-stator axial gap,the results that include rotor-stator interactions align much more closely with the URANS results.Nevertheless,the TSC simulations can still achieve speed-ups of several dozen times.Overall,the TSC method shows promising potential for application within the engineering community.展开更多
Proton exchange membrane fuel cells(PEMFCs)are considered as a promising renewable power source.However,the massive commercial application of PEMFCs has been greatly hindered by their high expense and less-satisfied p...Proton exchange membrane fuel cells(PEMFCs)are considered as a promising renewable power source.However,the massive commercial application of PEMFCs has been greatly hindered by their high expense and less-satisfied performance mainly due to the sluggish oxygen reduction reaction(ORR)kinetics even on state-of-the-art Pt catalyst.Octahedral PtNi nanoparticles(oct-PtNi NPs)with excellent ORR activity in a half-cell have been widely studied,while their performance in membrane electrode assembly(MEA)has much less reported.Herein,we investigated the MEA performance using the carbon supported oct-PtNi NPs(oct-PtNi/C)as the cathode catalyst.Under the mild acid washing condition,the surface Ni atoms of oct-PtNi/C were largely removed,and the performance of the MEA using the acid-leaching oct-PtNi/C(PNC-A)as the cathode catalyst was greatly improved.The maximum power density of the MEA reached 1.0 W·cm^(-2) with the cath-ode Pt loading of 0.2 mg·cm^(-2),which is 15%higher than that using Pt/C as the catalyst.After 30k cycles in the accelerated degradation test(ADT),the MEA using PNC-A as the catalyst showed a performance retention of 82%,higher than that of Pt/C(74%).The results reported here verify the possibility of using PNC-A as an advanced cathode catalyst in PEMFCs,thus enhancing the performance of PEMFCs while lowering the amount of expensive Pt.展开更多
A Tibetan art form bridges the past and present and connects cultures around the world.THANGKA,a unique form of Tibetan sacred painting,is gaining prominence globally due to its vibrant colors,exquisite craftsmanship,...A Tibetan art form bridges the past and present and connects cultures around the world.THANGKA,a unique form of Tibetan sacred painting,is gaining prominence globally due to its vibrant colors,exquisite craftsmanship,and profound religious and cultural significance.With the acceleration of globalization,this symbol of Tibetan culture that combines artistic expression with spirituality has become a bridge for cultural exchange between the East and the West.Recently,China Today spoke to Yixi Puncog,art collector and council member of the China Association for Preservation and Development of Tibetan Culture,to learn more about Thangka art,its role in international exchange,and how it is enhancing China’s cultural soft power.展开更多
Ningxia is an ethnic gathering area boasting abundant tourism and cultural resources.Developing the cause of tourism and culture is an important way to encourage all ethnic groups to respect differences,embrace divers...Ningxia is an ethnic gathering area boasting abundant tourism and cultural resources.Developing the cause of tourism and culture is an important way to encourage all ethnic groups to respect differences,embrace diversity,and demonstrate their interactions,exchanges,and integration in tourism activities.As an important preserve of the distinctive cultures of the Chinese nation and a prominent world tourist destination,Ningxia should strive to foster and consolidate the sense of a community with a shared future for the Chinese nation in developing its tourism and culture under the new historical conditions.It is imperative to advance the prosperity and development of tourism and culture in boosting ethnic interactions,exchanges,and integration through the formulation of tourism and cultural policies and plans,as well as the development and design of tourism and cultural projects.展开更多
We successfully incorporated phenyl groups into a small-molecule quaternary ammonium cross-linker and synthesized cross-linked polybenzimidazole membranes via a one-step cross-linking process.Compared with conventiona...We successfully incorporated phenyl groups into a small-molecule quaternary ammonium cross-linker and synthesized cross-linked polybenzimidazole membranes via a one-step cross-linking process.Compared with conventional quaternary ammonium-crosslinked benzimidazole membranes,the introduction of phenyl groups significantly increases the free volume within the membrane.After phosphoric acid doping,the benzimidazole membrane with larger free volume retains more phosphoric acid compared to conventional quaternary ammonium-crosslinked membranes,forming an extensive hydrogen-bonding network that effectively enhances its anhydrous proton conductivity.The anhydrous proton conductivity reaches 91 mS·cm^(-1)at 160℃,substantially higher than that of conventional quaternary ammonium-crosslinked membranes with the same mass fraction.Benefiting from the improved conductivity,the membrane electrode assembly exhibits reduced ohmic polarization,achieving a peak power density of 792 mW·cm^(-2)at 160℃.展开更多
Unmanned Aerial Vehicles(UAVs)in Flying Ad-Hoc Networks(FANETs)are widely used in both civilian and military fields,but they face severe security,trust,and privacy vulnerabilities due to their high mobility,dynamic to...Unmanned Aerial Vehicles(UAVs)in Flying Ad-Hoc Networks(FANETs)are widely used in both civilian and military fields,but they face severe security,trust,and privacy vulnerabilities due to their high mobility,dynamic topology,and open wireless channels.Existing security protocols for Mobile Ad-Hoc Networks(MANETs)cannot be directly applied to FANETs,as FANETs require lightweight,high real-time performance,and strong anonymity.The current FANETs security protocol cannot simultaneously meet the requirements of strong anonymity,high security,and low overhead in high dynamic and resource-constrained scenarios.To address these challenges,this paper proposes an Anonymous Authentication and Key Exchange Protocol(AAKE-OWA)for UAVs in FANETs based on OneWay Accumulators(OWA).During the UAV registration phase,the Key Management Center(KMC)generates an identity ticket for each UAV using OWA and transmits it securely to the UAV’s on-board tamper-proof module.In the key exchange phase,UAVs generate temporary authentication tickets with random numbers and compute the same session key leveraging the quasi-commutativity of OWA.For mutual anonymous authentication,UAVs encrypt random numbers with the session key and verify identities by comparing computed values with authentication values.Formal analysis using the Scyther tool confirms that the protocol resists identity spoofing,man-in-the-middle,and replay attacks.Through Burrows Abadi Needham(BAN)logic proof,it achieves mutual anonymity,prevents simulation and physical capture attacks,and ensures secure connectivity of 1.Experimental comparisons with existing protocols prove that the AAKE-OWA protocol has lower computational overhead,communication overhead,and storage overhead,making it more suitable for resource-constrained FANET scenarios.Performance comparison experiments show that,compared with other schemes,this scheme only requires 8 one-way accumulator operations and 4 symmetric encryption/decryption operations,with a total computational overhead as low as 2.3504 ms,a communication overhead of merely 1216 bits,and a storage overhead of 768 bits.We have achieved a reduction in computational costs from 6.3%to 90.3%,communication costs from 5.0%to 69.1%,and overall storage costs from 33%to 68%compared to existing solutions.It can meet the performance requirements of lightweight,real-time,and anonymity for unmanned aerial vehicles(UAVs)networks.展开更多
Clean energy devices have the potential to change the world and avoid future energy crises.The development of new energyefficient technologies helps reduce our dependence on limited fossil fuel resources.Hydrogen ener...Clean energy devices have the potential to change the world and avoid future energy crises.The development of new energyefficient technologies helps reduce our dependence on limited fossil fuel resources.Hydrogen energy is the key to achieving clean energy transition goals.Proton exchange membrane fuel cells play a critical role.Research and development of new hightech proton exchange membranes(PEMs)provide new horizons for the development of hydrogen energy.The use of carbon nanomaterials to improve PEM efficiency is one of the modern trends.The modification of modern membranes with fullerenes and their derivatives is an innovative strategy for increasing proton conductivity.This paper discusses the key principles of proton transport in PEMs modified with individual fullerenols,sulfofullerenes,carboxylated fullerenes,phosphofullerenes,and cianohydrofullerenes.The introduction of fullerene nanoparticles into polymer PEM induces an improvement in key properties.Summary information covers existing research on the use of fullerenes as nanoscale modifiers of proton-conducting materials.This review will help researchers to surpass the achieved results in the field of modern proton-conducting materials and stimulate the development of hydrogen energy.展开更多
Covalent organic framework ionomers enable synergistic efficient transport of protons and oxygen in medium-temperature proton exchange membrane fuel cells Proton exchange membrane fuel cells(PEMFCs),as clean and effic...Covalent organic framework ionomers enable synergistic efficient transport of protons and oxygen in medium-temperature proton exchange membrane fuel cells Proton exchange membrane fuel cells(PEMFCs),as clean and efficient energy technologies,are constrained in their performance enhancement by the sluggish oxygen reduction reaction(ORR)kinetics at the cathode,anode CO poisoning(e.g.,from methanol crossover)and intricate water management dilemmas[1].展开更多
The intractable trade-off between proton conductivity and vanadium ion selectivity,known as the‘transmission paradox’is a critical bottleneck hindering the commercialization of vanadium flow batteries(VFBs).Inspired...The intractable trade-off between proton conductivity and vanadium ion selectivity,known as the‘transmission paradox’is a critical bottleneck hindering the commercialization of vanadium flow batteries(VFBs).Inspired by the multi-stage,synergistic filtration mechanism of the mammalian glomerular filtration barrier,a novel,biomimetic hierarchical composite membrane has been fabricated via a precise layer-by-layer strategy on a polyethylene(PE)substrate.This membrane integrates a polydopamine(PDA)adhesion layer,a sulfonated Zr-MOF ion-sieving layer,and a synergistic polybenzimidazole(PBI)matrix.Spectroscopic analysis confirmed the formation of a critical bifunctional acid-base interface(-SO_(3)^(−)…H^(+)N-)between the MOF and PBI,which densifies the structure and optimizes ion pathways.The resulting composite membrane exhibits excellent mechanical robustness,superior chemical stability,and exceptional dimensional stability.Most significantly,this architecture successfully decouples the performance trade-off,demonstrating both high proton conductivity(11.11 mS·cm^(-1))and remarkably suppressed vanadium ion permeability(2.4×10^(−8) cm^(2)·min^(-1)).This combination yields an outstanding ion selectivity of 46.29×10^(4) S·min·cm^(-3).When tested in a VFB single cell,the membrane enabled a high energy efficiency of 81.6%at 200 mA·cm^(-2),an ultra-long self-discharge time of 2700 min,and excellent long-term cycling stability.This biomimetic design strategy effectively resolves the core‘transmission paradox’offering a promising pathway for next-generation high-performance flow batteries.展开更多
Anion exchange membranes(AEMs)are pivotal for advancing fuel cells and water electrolysis.However,their widespread adoption is hindered by the sluggish ion transport and inadequate durability.Herein,by tuning the numb...Anion exchange membranes(AEMs)are pivotal for advancing fuel cells and water electrolysis.However,their widespread adoption is hindered by the sluggish ion transport and inadequate durability.Herein,by tuning the number of conjugated aromatic rings and the branching sites within the monomers,a series of hyperbranched poly(aryl piperidinium)AEMs with coplanar polycyclic aromatic units are prepared to address the poor mechanical properties of rigid conjugated AEMs.The results indicate that the introduction of planar-conjugated triphenylene(TY)units in the polymer backbone facilitates ordered interchain aggregation driven byπ-πstacking interaction to form well-defined ion-conductive channels while suppressing excessive swelling and enhancing the membrane stability.The hyperbranched AEM containing the TY units(QTPTY)possesses excellent mechanical properties with 55.9 MPa of stress and 60.3%of strain.Additionally,the QTPTY membrane achieves an exceptional OH-conductivity of 146.4 m S cm^(-1)at 80℃,with 94.7%conductivity retention and mechanical properties reduction below 2%after 1600 h in 2 M Na OH.In an H_(2)/O_(2) fuel cell,QTPTY delivers a peak power density of 1.43 W cm^(-2),surpassing linear and the other twoπ-conjugated hyperbranched analogs.In water electrolysis,the AEM exhibits a current density of 2.30 A cm^(-2)at 1.80 V,exceeding the 2026 targets of the U.S.Department of Energy.This work demonstrates that planar-conjugated hyperbranched architectures have a significant potential in designing robust,high-performance AEMs for sustainable energy technologies.展开更多
The conservation of aquatic systems is closely linked to the maintenance and improvement of aquaculture products'yield and quality.In this experiment,a high-quality aquatic system was established,comprising Litope...The conservation of aquatic systems is closely linked to the maintenance and improvement of aquaculture products'yield and quality.In this experiment,a high-quality aquatic system was established,comprising Litopenaeus vannamei as a model species and two strains of Bacillus(W1 and XYB4)combined with sodium humate under zero-water exchange conditions.The growth performance,enzyme activity,and aquatic system microbial environment of L.vannamei were analyzed.Results showed that the combination of sodium humate and Bacillus strains effectively enhanced environmental conditions for the growth and reproduction of heterotrophic bacteria while inhibiting the growth of Vibrio species,including green and yellow variants.Microbiome analysis showed that the group treated with Bacillus strains combined with sodium humate exhibited significantly higher relative abundances of Firmicutes and Actinobacteriota than the other groups.Correspondingly,this treatment group showed substantially enhanced weight gain rate,specific growth rate,survival rate,and feed coefficient.Moreover,the phenol oxidase,catalase,lysozyme,and superoxide dismutase indexes of shrimps subjected to Bacillus–sodium humate treatment were considerably higher than those of the control group.These findings confirm that the combination of Bacillus and sodium humate has beneficial effects on shrimp growth and aquatic system quality control,providing a promising strategy for enhancing the efficiency of shrimp farming and aquaculture.展开更多
Proton exchange membranes(PEMs)play a central role in determining the efficiency,durability,and operational flexibility of PEM fuel cells(PEMFCs).However,conventional PEMs exhibit strong temperature-dependent proton-t...Proton exchange membranes(PEMs)play a central role in determining the efficiency,durability,and operational flexibility of PEM fuel cells(PEMFCs).However,conventional PEMs exhibit strong temperature-dependent proton-transport behavior,which limits their ability to support both rapid start-up at low temperatures and stable operation at elevated temperatures.Water-mediated PEMs show excellent conductivity under low-temperature and high-humidity conditions but suffer from dehydration and structural instability in the high-temperature regime.In contrast,water-independent PEMs,particularly phosphoric-acid-doped systems,conduct protons efficiently under anhydrous high-temperature conditions yet experience acid leaching that hampers room-temperature start-up and long-term durability.This review summarizes the fundamental proton-transport mechanisms that govern temperature-dependent performance and discusses recent advances in materials design aimed at enabling wide-temperature-range PEM operation.For water-mediated membranes,strategies such as incorporating hydrophilic fillers,constructing confined hydrophilic domains,and introducing additional proton-transfer sites have been developed to mitigate water loss and stabilize proton conduction.For water-independent membranes,approaches including strengthening polymer–acid interactions,engineering nanoscale confinement,designing multilayer architectures,and constructing multi–proton-carrier networks effectively improve acid retention and broaden operational temperature windows.Emerging fixed-carrier systems based on phosphonic-acid-grafted polymers,metal–organic frameworks,and covalent organic frameworks offer new pathways for stable anhydrous proton conduction across a wide temperature range.We conclude by outlining key challenges and future research opportunities,including reducing the dependence on volatile or leachable proton carriers,developing adaptive nanochannel architectures,improving anhydrous high-temperature conduction,and establishing scalable membrane fabrication methods.Continued innovation in these directions is expected to enable next-generation wide-temperature-range PEMs capable of flexible,high-efficiency operation from sub-zero to high-temperature conditions.展开更多
Converting CO_(2) into methanol(CH_(3)OH),a high-value-added liquid-phase product,through efficient and highly selective photocatalysis remains a significant challenge.Herein,we present a straightforward cation exchan...Converting CO_(2) into methanol(CH_(3)OH),a high-value-added liquid-phase product,through efficient and highly selective photocatalysis remains a significant challenge.Herein,we present a straightforward cation exchange strategy for the in-situ growth of BiVO_(4) on an InVO_(4) substrate to generate a Z-scheme heterojunction of InVO_(4)/BiVO_(4) .This in-situ partial transformation approach endows the InVO_(4)/BiVO_(4) heterojunction with a tightly connected interface,resulting in a significant improvement in charge separation efficiency between InVO_(4) and BiVO_(4).Moreover,the construction of the heterojunction reduces the formation energy barrier of the ^(*)COOH intermediate during the photoreduction of CO_(2) and increases the desorption energy barrier of the ^(*)CO intermediate,facilitating the deep reduction of ^(*)CO.Consequently,the InVO_(4)/BiVO_(4) heterojunction is capable of photocatalytic CO_(2) reduction to CH_(3)OH with high efficiency and selectivity.Under conditions where water serves as the electron source and a light intensity of 100 m W/cm^(2),the yield of CH_(3)OH reaches 130.5 μmol g^(-1)h^(-1) with a selectivity of 92 %,outperforming photocatalysts reported under similar conditions.展开更多
Coiled tube heat exchangers are widely preferred in shell structures due to their superior heat transfer performance,driven by favorable flow characteristics.This study investigates the effect of modifying coil and sh...Coiled tube heat exchangers are widely preferred in shell structures due to their superior heat transfer performance,driven by favorable flow characteristics.This study investigates the effect of modifying coil and shell configurations on heat transfer efficiency.Two key enhancements were examined:adding fins to the outer coil surface and integrating longitudinal slots within a hollowed shell.These modifications promote turbulence and extend heat transfer duration,thereby improving performance.However,they also introduce challenges,including increased pressure loss andmanufacturing complexity.Numerical simulationswere conducted usingANSYS Fluent 2024R1 under identical boundary conditions.With a fixed cold-side flow rate of 3 L/min,the input temperatures for the hot and cold fluids were 333.15 and 291.65 K,respectively.The hot-side flow rate varied between 2 and 6 L/min.Simulation outcomes were reported for the objectives of the study that included the improvement in heat exchangers’heat transfer enhancement.As it was indicated in the study outcomes,the average heat transfer rate increased by 15.56%,the overall heat transfer coefficient enhanced by about 29.51%,and the convective heat transfer coefficient improved by about 75.96%compared to the conventional shell-and-coil tube heat exchanger model.However,the modified technique resulted in a significant pressure drop.展开更多
This work contributes to the theoretical foundation for pricing in data markets and offers practical insights for managing digital data exchanges in the era of big data.We propose a structured pricing model for data e...This work contributes to the theoretical foundation for pricing in data markets and offers practical insights for managing digital data exchanges in the era of big data.We propose a structured pricing model for data exchanges transitioning from quasi-public to marketoriented operations.To address the complex dynamics among data exchanges,suppliers,and consumers,the authors develop a threestage Stackelberg game framework.In this model,the data exchange acts as a leader setting transaction commission rates,suppliers are intermediate leaders determining unit prices,and consumers are followers making purchasing decisions.Two pricing strategies are examined:the Independent Pricing Approach(IPA)and the novel Perfectly Competitive Pricing Approach(PCPA),which accounts for competition among data providers.Using backward induction,the study derives subgame-perfect equilibria and proves the existence and uniqueness of Stackelberg equilibria under both approaches.Extensive numerical simulations are carried out in the model,demonstrating that PCPA enhances data demander utility,encourages supplier competition,increases transaction volume,and improves the overall profitability and sustainability of data exchanges.Social welfare analysis further confirms PCPA’s superiority in promoting efficient and fair data markets.展开更多
University students,fashion models,street musicians,recent graduates…hundreds of aspiring singers gathered on the campus of the University of Nairobi in Kenya for a music audition.Some had guitars slung across their ...University students,fashion models,street musicians,recent graduates…hundreds of aspiring singers gathered on the campus of the University of Nairobi in Kenya for a music audition.Some had guitars slung across their backs,others drummed rhythms on hand drums,and a few performed melodies they had written on their phones.展开更多
Developing practical anion exchange membrane water electrolysis(AEMWE)technology encounters great challenges in not only cell efficiency but also long-term durability due to mechanical electrocatalyst detachment and e...Developing practical anion exchange membrane water electrolysis(AEMWE)technology encounters great challenges in not only cell efficiency but also long-term durability due to mechanical electrocatalyst detachment and electrochemical dissolution of active species,especially for the anodic oxygen evolution reaction(OER).Herein,a"two-pronged"approach is proposed to construct organophosphorus-protected NiFe layered double hydroxide catalysts on plasma-modified substrate,serving as an efficient and robust anode for practical AEMWE.Mechanical tests combined with operando spectroscopies and theoretical calculations demonstrate that the plasma modification strengthens the catalyst-substrate adhesion,while the organophosphorus protection prevents Fe leaching and promotes reaction kinetics during OER.The resultant electrode delivers an ultralow overpotential of 276 mV at 1 A cm^(-2),together with a remarkable stability at 0.5 A cm^(-2)over 500 h.Furthermore,assembling the optimized anode into an AEMWE device contributes to a minimized cell voltage of 1.70 V at 1 A cm^(-2),which sustains durable green hydrogen production with an economical energy consumption of 4.16 kW h Nm^(-3)H_(2).展开更多
ISO releases two standards for textiles.Recently,two international standards,ISO 8159:2025,Textiles-Morphology of fibres and yarns-Vocabulary,and ISO 17971:2025,Textiles-Smart textiles-Test method for determining the ...ISO releases two standards for textiles.Recently,two international standards,ISO 8159:2025,Textiles-Morphology of fibres and yarns-Vocabulary,and ISO 17971:2025,Textiles-Smart textiles-Test method for determining the screen-touch properties of fabrics,were officially released.They are of positive significance for eliminating technical ambiguities in exchanges on textile products and filling the gaps in international standards.展开更多
The increased interest in geothermal energy is evident,along with the exploitation of traditional hydrothermal systems,in the growing research and projects developing around the reuse of already-drilled oil,gas,and ex...The increased interest in geothermal energy is evident,along with the exploitation of traditional hydrothermal systems,in the growing research and projects developing around the reuse of already-drilled oil,gas,and exploration wells.The Republic of Croatia has around 4000 wells,however,due to a long period since most of these wells were drilled and completed,there is uncertainty about how many are available for retrofitting as deep-borehole heat exchangers.Nevertheless,as hydrocarbon production decreases,it is expected that the number of wells available for the revitalization and exploitation of geothermal energy will increase.The revitalization of wells via deep-borehole heat exchangers involves installing a coaxial heat exchanger and circulating the working fluid in a closed system,during which heat is transferred from the surrounding rock medium to the circulating fluid.Since drilled wells are not of uniformdepth and are located in areas with different thermal rock properties and geothermal gradients,an analysis was conducted to determine available thermal energy as a function of well depth,geothermal gradient,and circulating fluid flow rate.Additionally,an economic analysis was performed to determine the benefits of retrofitting existing assets,such as drilled wells,compared to drilling new wells to obtain the same amount of thermal energy.展开更多
文摘The ionothermal reaction between CuCl_(2),1,4-bis(1,2,4-triazol-1-ylmethyl)benzene(BBTZ),and(NH_(4))_(6)Mo_(7)O_(24) in 1-ethyl-3-methylimidazolium bromide((Emim)Br)led to a new octamolybdate-based coordination polymer(Emim)2[Cu(BBTZ)_(2)(β-Mo_(8)O_(26))](Mo_(8)-CP).Mo_(8)-CP was characterized by elemental analysis,thermogravime-try,IR,powder X-ray diffraction,and single-crystal X-ray diffraction.In Mo_(8)-CP,structural analysis reveals that Cu coordinates with BBTZ ligands to form an interlocked 1D chain.These chains are further bridged by(β-Mo_(8)O_(26))^(4-)to construct a 3D coordination polymer.Notably,(Emim)^(+)acts as a structure-directing agent,occupying the channels of the 3D coordination polymer.Based on this unique structure,the ion exchange properties of Mo_(8)-CP toward rare-earth ions were investigated.It has been found that the luminescent color of the material can be successfully regulat-ed by introducing Eu^(3+)or Tb^(3+)through ion exchange.CCDC:2475110,Mo_(8)-CP.
文摘Circumferentially non-uniform tip clearances induced by rotor eccentricity significantly affect the overall performance of axial compressors,particularly the stability margin.Currently,Computational Fluid Dynamics(CFD)plays a crucial role in the aerodynamic analysis of eccentric compressors.However,conventional full-annulus Unsteady Reynolds-Averaged Navier-Stokes(URANS)simulations are prohibitively expensive for routine design and analysis purposes.To address this issue,the paper presents a novel Fourier-based method,called the Time-Space Collocation(TSC)method,for efficient simulations of eccentric compressors.This method coherently treats temporal and spatial harmonics,making it well-suited to tackle the rotor eccentricity problem,as the perturbation waves induced by eccentricity are time-periodic with respect to the rotor and space-periodic with respect to the stator.Three numerical cases,including NASA Rotor 67,original Stage 67,and Stage 67 with a reduced rotor-stator axial gap,were conducted to verify the effectiveness of the TSC method.The results indicate that,for the rotor eccentricity levels studied in this paper,the influence of weak rotor-stator interactions can be disregarded in the original Stage 67.In this situation,applying three harmonics can accurately capture both the performance variations and the non-uniformly distributed flowfields of eccentric compressors,while achieving a reduction in run time by two orders of magnitude compared to full-annulus URANS simulations.However,in Stage 67 with a reduced rotor-stator axial gap,the results that include rotor-stator interactions align much more closely with the URANS results.Nevertheless,the TSC simulations can still achieve speed-ups of several dozen times.Overall,the TSC method shows promising potential for application within the engineering community.
基金supported by grants from the Natural Science Foundation of China(22362031 and 21805121)the Science and Technology Project of Yunnan Province(2019FD137)。
文摘Proton exchange membrane fuel cells(PEMFCs)are considered as a promising renewable power source.However,the massive commercial application of PEMFCs has been greatly hindered by their high expense and less-satisfied performance mainly due to the sluggish oxygen reduction reaction(ORR)kinetics even on state-of-the-art Pt catalyst.Octahedral PtNi nanoparticles(oct-PtNi NPs)with excellent ORR activity in a half-cell have been widely studied,while their performance in membrane electrode assembly(MEA)has much less reported.Herein,we investigated the MEA performance using the carbon supported oct-PtNi NPs(oct-PtNi/C)as the cathode catalyst.Under the mild acid washing condition,the surface Ni atoms of oct-PtNi/C were largely removed,and the performance of the MEA using the acid-leaching oct-PtNi/C(PNC-A)as the cathode catalyst was greatly improved.The maximum power density of the MEA reached 1.0 W·cm^(-2) with the cath-ode Pt loading of 0.2 mg·cm^(-2),which is 15%higher than that using Pt/C as the catalyst.After 30k cycles in the accelerated degradation test(ADT),the MEA using PNC-A as the catalyst showed a performance retention of 82%,higher than that of Pt/C(74%).The results reported here verify the possibility of using PNC-A as an advanced cathode catalyst in PEMFCs,thus enhancing the performance of PEMFCs while lowering the amount of expensive Pt.
文摘A Tibetan art form bridges the past and present and connects cultures around the world.THANGKA,a unique form of Tibetan sacred painting,is gaining prominence globally due to its vibrant colors,exquisite craftsmanship,and profound religious and cultural significance.With the acceleration of globalization,this symbol of Tibetan culture that combines artistic expression with spirituality has become a bridge for cultural exchange between the East and the West.Recently,China Today spoke to Yixi Puncog,art collector and council member of the China Association for Preservation and Development of Tibetan Culture,to learn more about Thangka art,its role in international exchange,and how it is enhancing China’s cultural soft power.
文摘Ningxia is an ethnic gathering area boasting abundant tourism and cultural resources.Developing the cause of tourism and culture is an important way to encourage all ethnic groups to respect differences,embrace diversity,and demonstrate their interactions,exchanges,and integration in tourism activities.As an important preserve of the distinctive cultures of the Chinese nation and a prominent world tourist destination,Ningxia should strive to foster and consolidate the sense of a community with a shared future for the Chinese nation in developing its tourism and culture under the new historical conditions.It is imperative to advance the prosperity and development of tourism and culture in boosting ethnic interactions,exchanges,and integration through the formulation of tourism and cultural policies and plans,as well as the development and design of tourism and cultural projects.
基金Funded in part by the National Key Research and Development Program of China(No.2023YFB4006302)。
文摘We successfully incorporated phenyl groups into a small-molecule quaternary ammonium cross-linker and synthesized cross-linked polybenzimidazole membranes via a one-step cross-linking process.Compared with conventional quaternary ammonium-crosslinked benzimidazole membranes,the introduction of phenyl groups significantly increases the free volume within the membrane.After phosphoric acid doping,the benzimidazole membrane with larger free volume retains more phosphoric acid compared to conventional quaternary ammonium-crosslinked membranes,forming an extensive hydrogen-bonding network that effectively enhances its anhydrous proton conductivity.The anhydrous proton conductivity reaches 91 mS·cm^(-1)at 160℃,substantially higher than that of conventional quaternary ammonium-crosslinked membranes with the same mass fraction.Benefiting from the improved conductivity,the membrane electrode assembly exhibits reduced ohmic polarization,achieving a peak power density of 792 mW·cm^(-2)at 160℃.
基金supported in part by National Natural Science Foundation of China(under Grant 61902163)the Jiangsu“Qing Lan Project”,Natural Science Foundation of the Jiangsu Higher Education Institutions of China(Major Research Project:23KJA520007)Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.SJCX25_1303).
文摘Unmanned Aerial Vehicles(UAVs)in Flying Ad-Hoc Networks(FANETs)are widely used in both civilian and military fields,but they face severe security,trust,and privacy vulnerabilities due to their high mobility,dynamic topology,and open wireless channels.Existing security protocols for Mobile Ad-Hoc Networks(MANETs)cannot be directly applied to FANETs,as FANETs require lightweight,high real-time performance,and strong anonymity.The current FANETs security protocol cannot simultaneously meet the requirements of strong anonymity,high security,and low overhead in high dynamic and resource-constrained scenarios.To address these challenges,this paper proposes an Anonymous Authentication and Key Exchange Protocol(AAKE-OWA)for UAVs in FANETs based on OneWay Accumulators(OWA).During the UAV registration phase,the Key Management Center(KMC)generates an identity ticket for each UAV using OWA and transmits it securely to the UAV’s on-board tamper-proof module.In the key exchange phase,UAVs generate temporary authentication tickets with random numbers and compute the same session key leveraging the quasi-commutativity of OWA.For mutual anonymous authentication,UAVs encrypt random numbers with the session key and verify identities by comparing computed values with authentication values.Formal analysis using the Scyther tool confirms that the protocol resists identity spoofing,man-in-the-middle,and replay attacks.Through Burrows Abadi Needham(BAN)logic proof,it achieves mutual anonymity,prevents simulation and physical capture attacks,and ensures secure connectivity of 1.Experimental comparisons with existing protocols prove that the AAKE-OWA protocol has lower computational overhead,communication overhead,and storage overhead,making it more suitable for resource-constrained FANET scenarios.Performance comparison experiments show that,compared with other schemes,this scheme only requires 8 one-way accumulator operations and 4 symmetric encryption/decryption operations,with a total computational overhead as low as 2.3504 ms,a communication overhead of merely 1216 bits,and a storage overhead of 768 bits.We have achieved a reduction in computational costs from 6.3%to 90.3%,communication costs from 5.0%to 69.1%,and overall storage costs from 33%to 68%compared to existing solutions.It can meet the performance requirements of lightweight,real-time,and anonymity for unmanned aerial vehicles(UAVs)networks.
基金supported by the Russian Science Foundation Project(23-13-00328)。
文摘Clean energy devices have the potential to change the world and avoid future energy crises.The development of new energyefficient technologies helps reduce our dependence on limited fossil fuel resources.Hydrogen energy is the key to achieving clean energy transition goals.Proton exchange membrane fuel cells play a critical role.Research and development of new hightech proton exchange membranes(PEMs)provide new horizons for the development of hydrogen energy.The use of carbon nanomaterials to improve PEM efficiency is one of the modern trends.The modification of modern membranes with fullerenes and their derivatives is an innovative strategy for increasing proton conductivity.This paper discusses the key principles of proton transport in PEMs modified with individual fullerenols,sulfofullerenes,carboxylated fullerenes,phosphofullerenes,and cianohydrofullerenes.The introduction of fullerene nanoparticles into polymer PEM induces an improvement in key properties.Summary information covers existing research on the use of fullerenes as nanoscale modifiers of proton-conducting materials.This review will help researchers to surpass the achieved results in the field of modern proton-conducting materials and stimulate the development of hydrogen energy.
文摘Covalent organic framework ionomers enable synergistic efficient transport of protons and oxygen in medium-temperature proton exchange membrane fuel cells Proton exchange membrane fuel cells(PEMFCs),as clean and efficient energy technologies,are constrained in their performance enhancement by the sluggish oxygen reduction reaction(ORR)kinetics at the cathode,anode CO poisoning(e.g.,from methanol crossover)and intricate water management dilemmas[1].
基金supported by the Natural Science Foundation of Liaoning Province(Grant Nos:2025-BSLH-247,2025-BSLH-246)Liaoning Provincial Department of Education Foundation(Grant Nos:LJ212410148012,LJ242510148002)+1 种基金Inner Mongolia’s Key R&D and Achievement Industrialization Program(Grant No:2025YFHH0017)China Postdoctoral Science Foundation(Grant Nos:2025MD774148,2025M770082).
文摘The intractable trade-off between proton conductivity and vanadium ion selectivity,known as the‘transmission paradox’is a critical bottleneck hindering the commercialization of vanadium flow batteries(VFBs).Inspired by the multi-stage,synergistic filtration mechanism of the mammalian glomerular filtration barrier,a novel,biomimetic hierarchical composite membrane has been fabricated via a precise layer-by-layer strategy on a polyethylene(PE)substrate.This membrane integrates a polydopamine(PDA)adhesion layer,a sulfonated Zr-MOF ion-sieving layer,and a synergistic polybenzimidazole(PBI)matrix.Spectroscopic analysis confirmed the formation of a critical bifunctional acid-base interface(-SO_(3)^(−)…H^(+)N-)between the MOF and PBI,which densifies the structure and optimizes ion pathways.The resulting composite membrane exhibits excellent mechanical robustness,superior chemical stability,and exceptional dimensional stability.Most significantly,this architecture successfully decouples the performance trade-off,demonstrating both high proton conductivity(11.11 mS·cm^(-1))and remarkably suppressed vanadium ion permeability(2.4×10^(−8) cm^(2)·min^(-1)).This combination yields an outstanding ion selectivity of 46.29×10^(4) S·min·cm^(-3).When tested in a VFB single cell,the membrane enabled a high energy efficiency of 81.6%at 200 mA·cm^(-2),an ultra-long self-discharge time of 2700 min,and excellent long-term cycling stability.This biomimetic design strategy effectively resolves the core‘transmission paradox’offering a promising pathway for next-generation high-performance flow batteries.
基金the financial support from the National Natural Science Foundation of China(Grant Nos.22278340&22078272)。
文摘Anion exchange membranes(AEMs)are pivotal for advancing fuel cells and water electrolysis.However,their widespread adoption is hindered by the sluggish ion transport and inadequate durability.Herein,by tuning the number of conjugated aromatic rings and the branching sites within the monomers,a series of hyperbranched poly(aryl piperidinium)AEMs with coplanar polycyclic aromatic units are prepared to address the poor mechanical properties of rigid conjugated AEMs.The results indicate that the introduction of planar-conjugated triphenylene(TY)units in the polymer backbone facilitates ordered interchain aggregation driven byπ-πstacking interaction to form well-defined ion-conductive channels while suppressing excessive swelling and enhancing the membrane stability.The hyperbranched AEM containing the TY units(QTPTY)possesses excellent mechanical properties with 55.9 MPa of stress and 60.3%of strain.Additionally,the QTPTY membrane achieves an exceptional OH-conductivity of 146.4 m S cm^(-1)at 80℃,with 94.7%conductivity retention and mechanical properties reduction below 2%after 1600 h in 2 M Na OH.In an H_(2)/O_(2) fuel cell,QTPTY delivers a peak power density of 1.43 W cm^(-2),surpassing linear and the other twoπ-conjugated hyperbranched analogs.In water electrolysis,the AEM exhibits a current density of 2.30 A cm^(-2)at 1.80 V,exceeding the 2026 targets of the U.S.Department of Energy.This work demonstrates that planar-conjugated hyperbranched architectures have a significant potential in designing robust,high-performance AEMs for sustainable energy technologies.
基金supported by the National Key R&D Program of China(No.2023YFD2401703)。
文摘The conservation of aquatic systems is closely linked to the maintenance and improvement of aquaculture products'yield and quality.In this experiment,a high-quality aquatic system was established,comprising Litopenaeus vannamei as a model species and two strains of Bacillus(W1 and XYB4)combined with sodium humate under zero-water exchange conditions.The growth performance,enzyme activity,and aquatic system microbial environment of L.vannamei were analyzed.Results showed that the combination of sodium humate and Bacillus strains effectively enhanced environmental conditions for the growth and reproduction of heterotrophic bacteria while inhibiting the growth of Vibrio species,including green and yellow variants.Microbiome analysis showed that the group treated with Bacillus strains combined with sodium humate exhibited significantly higher relative abundances of Firmicutes and Actinobacteriota than the other groups.Correspondingly,this treatment group showed substantially enhanced weight gain rate,specific growth rate,survival rate,and feed coefficient.Moreover,the phenol oxidase,catalase,lysozyme,and superoxide dismutase indexes of shrimps subjected to Bacillus–sodium humate treatment were considerably higher than those of the control group.These findings confirm that the combination of Bacillus and sodium humate has beneficial effects on shrimp growth and aquatic system quality control,providing a promising strategy for enhancing the efficiency of shrimp farming and aquaculture.
基金supported by the National Natural Science Foundation of China(52277225)the Fundamental Research Funds for the Central Universities(xtr052024009).
文摘Proton exchange membranes(PEMs)play a central role in determining the efficiency,durability,and operational flexibility of PEM fuel cells(PEMFCs).However,conventional PEMs exhibit strong temperature-dependent proton-transport behavior,which limits their ability to support both rapid start-up at low temperatures and stable operation at elevated temperatures.Water-mediated PEMs show excellent conductivity under low-temperature and high-humidity conditions but suffer from dehydration and structural instability in the high-temperature regime.In contrast,water-independent PEMs,particularly phosphoric-acid-doped systems,conduct protons efficiently under anhydrous high-temperature conditions yet experience acid leaching that hampers room-temperature start-up and long-term durability.This review summarizes the fundamental proton-transport mechanisms that govern temperature-dependent performance and discusses recent advances in materials design aimed at enabling wide-temperature-range PEM operation.For water-mediated membranes,strategies such as incorporating hydrophilic fillers,constructing confined hydrophilic domains,and introducing additional proton-transfer sites have been developed to mitigate water loss and stabilize proton conduction.For water-independent membranes,approaches including strengthening polymer–acid interactions,engineering nanoscale confinement,designing multilayer architectures,and constructing multi–proton-carrier networks effectively improve acid retention and broaden operational temperature windows.Emerging fixed-carrier systems based on phosphonic-acid-grafted polymers,metal–organic frameworks,and covalent organic frameworks offer new pathways for stable anhydrous proton conduction across a wide temperature range.We conclude by outlining key challenges and future research opportunities,including reducing the dependence on volatile or leachable proton carriers,developing adaptive nanochannel architectures,improving anhydrous high-temperature conduction,and establishing scalable membrane fabrication methods.Continued innovation in these directions is expected to enable next-generation wide-temperature-range PEMs capable of flexible,high-efficiency operation from sub-zero to high-temperature conditions.
基金financially supported the National Key R&D Program of China (No.2022YFA1502902)the National Natural Science Foundation of China (NSFC,Nos.22475152 and U21A20286)the 111 Project of China (No.D17003)。
文摘Converting CO_(2) into methanol(CH_(3)OH),a high-value-added liquid-phase product,through efficient and highly selective photocatalysis remains a significant challenge.Herein,we present a straightforward cation exchange strategy for the in-situ growth of BiVO_(4) on an InVO_(4) substrate to generate a Z-scheme heterojunction of InVO_(4)/BiVO_(4) .This in-situ partial transformation approach endows the InVO_(4)/BiVO_(4) heterojunction with a tightly connected interface,resulting in a significant improvement in charge separation efficiency between InVO_(4) and BiVO_(4).Moreover,the construction of the heterojunction reduces the formation energy barrier of the ^(*)COOH intermediate during the photoreduction of CO_(2) and increases the desorption energy barrier of the ^(*)CO intermediate,facilitating the deep reduction of ^(*)CO.Consequently,the InVO_(4)/BiVO_(4) heterojunction is capable of photocatalytic CO_(2) reduction to CH_(3)OH with high efficiency and selectivity.Under conditions where water serves as the electron source and a light intensity of 100 m W/cm^(2),the yield of CH_(3)OH reaches 130.5 μmol g^(-1)h^(-1) with a selectivity of 92 %,outperforming photocatalysts reported under similar conditions.
文摘Coiled tube heat exchangers are widely preferred in shell structures due to their superior heat transfer performance,driven by favorable flow characteristics.This study investigates the effect of modifying coil and shell configurations on heat transfer efficiency.Two key enhancements were examined:adding fins to the outer coil surface and integrating longitudinal slots within a hollowed shell.These modifications promote turbulence and extend heat transfer duration,thereby improving performance.However,they also introduce challenges,including increased pressure loss andmanufacturing complexity.Numerical simulationswere conducted usingANSYS Fluent 2024R1 under identical boundary conditions.With a fixed cold-side flow rate of 3 L/min,the input temperatures for the hot and cold fluids were 333.15 and 291.65 K,respectively.The hot-side flow rate varied between 2 and 6 L/min.Simulation outcomes were reported for the objectives of the study that included the improvement in heat exchangers’heat transfer enhancement.As it was indicated in the study outcomes,the average heat transfer rate increased by 15.56%,the overall heat transfer coefficient enhanced by about 29.51%,and the convective heat transfer coefficient improved by about 75.96%compared to the conventional shell-and-coil tube heat exchanger model.However,the modified technique resulted in a significant pressure drop.
基金supported by the National Natural Science Foundation of China[grant numbers 12171158,12371474 and 12571510]Fundamental Research Funds for the Central Universities[grant number 2025ECNU-WLJC006].
文摘This work contributes to the theoretical foundation for pricing in data markets and offers practical insights for managing digital data exchanges in the era of big data.We propose a structured pricing model for data exchanges transitioning from quasi-public to marketoriented operations.To address the complex dynamics among data exchanges,suppliers,and consumers,the authors develop a threestage Stackelberg game framework.In this model,the data exchange acts as a leader setting transaction commission rates,suppliers are intermediate leaders determining unit prices,and consumers are followers making purchasing decisions.Two pricing strategies are examined:the Independent Pricing Approach(IPA)and the novel Perfectly Competitive Pricing Approach(PCPA),which accounts for competition among data providers.Using backward induction,the study derives subgame-perfect equilibria and proves the existence and uniqueness of Stackelberg equilibria under both approaches.Extensive numerical simulations are carried out in the model,demonstrating that PCPA enhances data demander utility,encourages supplier competition,increases transaction volume,and improves the overall profitability and sustainability of data exchanges.Social welfare analysis further confirms PCPA’s superiority in promoting efficient and fair data markets.
文摘University students,fashion models,street musicians,recent graduates…hundreds of aspiring singers gathered on the campus of the University of Nairobi in Kenya for a music audition.Some had guitars slung across their backs,others drummed rhythms on hand drums,and a few performed melodies they had written on their phones.
基金supported by the Natural Science Foundation of Shanghai Municipality(25ZR1401027)the National Natural Science Foundation of China(22572041,11975081,22309037,52274297,and 22402083)+1 种基金Hainan Provincial Natural Science Foundation of China(225YXQN587)Start-up Research Foundation of Hainan University(KYQD(ZR)23035)。
文摘Developing practical anion exchange membrane water electrolysis(AEMWE)technology encounters great challenges in not only cell efficiency but also long-term durability due to mechanical electrocatalyst detachment and electrochemical dissolution of active species,especially for the anodic oxygen evolution reaction(OER).Herein,a"two-pronged"approach is proposed to construct organophosphorus-protected NiFe layered double hydroxide catalysts on plasma-modified substrate,serving as an efficient and robust anode for practical AEMWE.Mechanical tests combined with operando spectroscopies and theoretical calculations demonstrate that the plasma modification strengthens the catalyst-substrate adhesion,while the organophosphorus protection prevents Fe leaching and promotes reaction kinetics during OER.The resultant electrode delivers an ultralow overpotential of 276 mV at 1 A cm^(-2),together with a remarkable stability at 0.5 A cm^(-2)over 500 h.Furthermore,assembling the optimized anode into an AEMWE device contributes to a minimized cell voltage of 1.70 V at 1 A cm^(-2),which sustains durable green hydrogen production with an economical energy consumption of 4.16 kW h Nm^(-3)H_(2).
文摘ISO releases two standards for textiles.Recently,two international standards,ISO 8159:2025,Textiles-Morphology of fibres and yarns-Vocabulary,and ISO 17971:2025,Textiles-Smart textiles-Test method for determining the screen-touch properties of fabrics,were officially released.They are of positive significance for eliminating technical ambiguities in exchanges on textile products and filling the gaps in international standards.
文摘The increased interest in geothermal energy is evident,along with the exploitation of traditional hydrothermal systems,in the growing research and projects developing around the reuse of already-drilled oil,gas,and exploration wells.The Republic of Croatia has around 4000 wells,however,due to a long period since most of these wells were drilled and completed,there is uncertainty about how many are available for retrofitting as deep-borehole heat exchangers.Nevertheless,as hydrocarbon production decreases,it is expected that the number of wells available for the revitalization and exploitation of geothermal energy will increase.The revitalization of wells via deep-borehole heat exchangers involves installing a coaxial heat exchanger and circulating the working fluid in a closed system,during which heat is transferred from the surrounding rock medium to the circulating fluid.Since drilled wells are not of uniformdepth and are located in areas with different thermal rock properties and geothermal gradients,an analysis was conducted to determine available thermal energy as a function of well depth,geothermal gradient,and circulating fluid flow rate.Additionally,an economic analysis was performed to determine the benefits of retrofitting existing assets,such as drilled wells,compared to drilling new wells to obtain the same amount of thermal energy.
