Microrobots play an essential role in early diagnosis and precision medicine with the increasing demands for controllability in bio-medicine and micromanipulation,which can complete the pre-designed behavior under ext...Microrobots play an essential role in early diagnosis and precision medicine with the increasing demands for controllability in bio-medicine and micromanipulation,which can complete the pre-designed behavior under external stimulation.However,most microrobots are currently made of a single material system and focus on fabricating a driving module as the main structure of microrobots.This hinders the integration of diverse functions in one microrobot to fulfill the complex application.Here,a multi-material and multi-module hand-microrobot based on femtosecond laser direct writing technology is proposed,which has a pH-responsive capturing module and a magnetic-responsive transportation module(MRTM).This microrobot can not only respond to pH for capturing and releasing objects,but also respond to magnetic fields for cargo delivery even with obstacles.The two responding modules of the hand-microrobot are fabricated independently,and can collaborate with each other to achieve the delivery of target objects like polystyrene(PS)microsphere(10µm)or 786-O cell by capturing,transporting,and spatial rolling.Besides,the MRTM can be locally fabricated on any prefabricated static structure,so that the whole microrobot can achieve controllable motion.This strategy is expected to be used to manipulate cells,deliver drugs for precise treatment,and environmental treatment.展开更多
Biomass-derived carbon materials are favored for their abundance and sustainability,and ease of preparation and modification.By surface activation and modification they can have a good electrical conductivity,excellen...Biomass-derived carbon materials are favored for their abundance and sustainability,and ease of preparation and modification.By surface activation and modification they can have a good electrical conductivity,excellent catalytic activity,a remarkable adsorption capacity,and different interfacial physicochemical functionalities.Surface-modified biochars have found wide applications in energy storage,environmental remediation,and catalysis.However,achieving precise and controllable modification of their active sites remains a challenge.Recent advances and future prospects for controlling their surface morphology,defect engineering,and surface coating strategies,with particular attention to their means of fabrication,are reviewed.展开更多
Nickel-catalyzed borylation of aryl nonaflates with B2pin2 could be realized,which proceeded effectively by means of C—O bond functionalization to afford a wide variety of valuable arylboronates in moderate to excell...Nickel-catalyzed borylation of aryl nonaflates with B2pin2 could be realized,which proceeded effectively by means of C—O bond functionalization to afford a wide variety of valuable arylboronates in moderate to excellent yields with good functionality compatibility.In addition,the gram-scale synthesis and the application of the approach in the late-stage elaboration of aryl nonaflate derived from pterostilbene could also be achieved.展开更多
In this study,sawdust served as a carbon source and urea as a nitrogen source to synthesize carbonsupported,nitrogen-doped TiO_(2)composites via a one-pot solvothermal method.The composites were characterized using FT...In this study,sawdust served as a carbon source and urea as a nitrogen source to synthesize carbonsupported,nitrogen-doped TiO_(2)composites via a one-pot solvothermal method.The composites were characterized using FTIR,powder X-ray diffraction,X-ray photoelectron spectroscopy,ultraviolet-visible diffuse reflectance spectroscopy,thermogravimetry-derivative thermogravimetry,scanning electron microscopy-energy dispersive spectroscopy,and transmission electron microscopy.Results indicated that all synthesized composites exhibit the anatase phase,with those calcined at 800℃ demonstrating enhanced crystallinity.Nitrogen is incorporated into the TiO_(2)lattice,while carbon is predominantly located on the surface.Photodegradation experiments showed that 20 mg of composite N-TiO_(2)/C-800 achieved degradation rates of 93.4% for methylene blue(20 mg·L^(-1),50 mL)and 99.4% for oxytetracycline(20 mg·L^(-1),50 mL)within 30 min.Free radical capture experiments indicated that h+was the primary active species in the photocatalytic degradation process.展开更多
In modern industrial production,foreign object detection in complex environments is crucial to ensure product quality and production safety.Detection systems based on deep-learning image processing algorithms often fa...In modern industrial production,foreign object detection in complex environments is crucial to ensure product quality and production safety.Detection systems based on deep-learning image processing algorithms often face challenges with handling high-resolution images and achieving accurate detection against complex backgrounds.To address these issues,this study employs the PatchCore unsupervised anomaly detection algorithm combined with data augmentation techniques to enhance the system’s generalization capability across varying lighting conditions,viewing angles,and object scales.The proposed method is evaluated in a complex industrial detection scenario involving the bogie of an electric multiple unit(EMU).A dataset consisting of complex backgrounds,diverse lighting conditions,and multiple viewing angles is constructed to validate the performance of the detection system in real industrial environments.Experimental results show that the proposed model achieves an average area under the receiver operating characteristic curve(AUROC)of 0.92 and an average F1 score of 0.85.Combined with data augmentation,the proposed model exhibits improvements in AUROC by 0.06 and F1 score by 0.03,demonstrating enhanced accuracy and robustness for foreign object detection in complex industrial settings.In addition,the effects of key factors on detection performance are systematically analyzed,providing practical guidance for parameter selection in real industrial applications.展开更多
The design of zero-background fluorescent sensing materials with specific functionalities is of great significance.Here,a special Eu-MOF with nonfluorescent emission was designed and driven by H_(2)O-induced cascade r...The design of zero-background fluorescent sensing materials with specific functionalities is of great significance.Here,a special Eu-MOF with nonfluorescent emission was designed and driven by H_(2)O-induced cascade reaction through modulating the number of hydroxyl groups in ligands to enhance the signal-to-noise ratio,sensitivity,and reaction speed toward triacetone triperoxide(TATP).It is found that only when the ligand was selected as 2,5-dihydroxyterephthalic acid(DHTA),and with the introduction of H_(2)O,the intramolecular hydrogen bond could be changed to a weaker intermolecular hydrogen bond,which would be interrupted and oxidized from the original enol structure to ketone,producing the fluorescence turn-on response toward TATP.The special Eu-MOF exhibited a high-performance sensing for TATP,with fast response(<1 s),low limit of detection(LOD,36.1 nM),superior selectivity even in the presence of 28 kinds of interferents,including the very similar hydrogen peroxide,strong robustness,and a practical detecting ability of 5 pg airborne TATP particle.Furthermore,we validated the practical feasibility of the specific Eu-MOF by integrating a sensing chip into a portable detector,thereby confirming that this MOF exhibits considerable potential for trace-level TATP detection in real-world application scenarios.The present nonfluorescent MOF design strategy and the elaborate modulation of the conformation in MOF structure would provide a new pathway for the exploration of novel functional MOFs as well as high-performance sensing methodologies.展开更多
With the development of electronic technologies,piezoresistive sensors have attracted increasing attention.Among them,aerogels with high elasticity,as a type of three-dimensional porous material,are widely used in the...With the development of electronic technologies,piezoresistive sensors have attracted increasing attention.Among them,aerogels with high elasticity,as a type of three-dimensional porous material,are widely used in the field of piezoresistive sensors.Nowadays,with the extension of science and technology areas,fields involving low-temperature environments have emerged,which has led to an increasing demand for piezoresistive sensors that can serve at cryogenic temperatures.However,most studies on aerogels have only focused on their sensing performance at room temperature,and there is a lack of research on aerogel sensors that can work at low temperatures.In this work,piezoresistive sensors based on cotton fibers were proposed for applications at 77 K.As one of the most important natural polymers,cotton fibers have the ability to maintain elasticity at very low temperatures.Cotton fiber-based aerogels with high elasticity and cyclic stability were obtained by controlling the freeze-casting parameters and size distribution of cotton fibers,and they showed excellent pressure sensing properties,including a wide sensing range and remarkable long-term stability.This study bridges the gap in cryogenic sensing materials and provides insights into microstructure-property relationships,advancing applications in aerospace and cryogenic engineering.展开更多
Biopolymeric nanocomposites have attracted considerable attention because of their biocompatibility,biodegradability,and unique physicochemical properties.It is essential to manufacture three-dimensional(3D)biocompati...Biopolymeric nanocomposites have attracted considerable attention because of their biocompatibility,biodegradability,and unique physicochemical properties.It is essential to manufacture three-dimensional(3D)biocompatible micro/nanostructures using biopolymeric nanocomposites.Herein,we demonstrate the high-fidelity fabrication of biocompatible 3D features with sub-50 nm resolution using femtosecond laser direct writing(FsLDW)of a biopolymeric nanocomposite composed of egg white and sulfonated graphene(S-graphene).The biopolymer nanocomposite acts as a negative photoresist suitable for water-based lithography.The introduction of S-graphene not only dramatically lowered the laser power threshold but also significantly modulated the morphology of the 3D features constructed by FsLDW.Microstructures with porous,rough,or smooth morphologies were obtained by optimizing the S-graphene concentration and laser scanning speed.The fabricated egg-white/S-graphene microstructures exhibited biocompatibility and environmental degradability.Egg white/S-graphene was also employed to fabricate diffractive gratings with superior optical quality.This study provides a promising method to manufacture biocompatible 3D features with controllable morphology,which has potential applications in biological and photonic fields.展开更多
Construction of electron donor-acceptor(D-A)conjugated system is an established strategy for achieving reverse saturable absorption(RSA)and broadband optical limiting(OL).Nevertheless,organic materials exhibit OL abil...Construction of electron donor-acceptor(D-A)conjugated system is an established strategy for achieving reverse saturable absorption(RSA)and broadband optical limiting(OL).Nevertheless,organic materials exhibit OL ability across the visible to near-infrared-II spectra range remain scarce.Herein,a series of D-A typeπ-conjugated copolymers with ultra-narrow bandgaps(0.62-0.76 e V)and strong ICT absorption were synthesized by coupling electron-withdrawing block[1,2,5]thiadiazolo[3,4-g]quinoxaline(TQ)with various electron-donating groups(thiophene,selenophene,bithiophene,di(thiophen-2-yl)ethene,and thienothiophene for P1-P5,respectively).Z-scan experiments reveal that all copolymers exhibit RSA behaviours at both 532 and 1064 nm,while P1,P3 and P4 maintain RSA performance extending to 1600 nm.Among all copolymers,P5 exhibits the strongest RSA performance upon both 532 and 1064 nm laser pulses,with the highest nonlinear absorption coefficient(β_(eff))of 51.5 and 49.4 cm·GW^(-1),respectively,and the lowest OL onset fluence(Fon)of 0.31 and 0.38 J·cm^(-2),respectively.In contrast,P4 shows optimal RSA property at 1600 nm laser pulse,withβeff of 13.1 cm·GW^(-1)and Fon of 1.43 J·cm^(-2),respectively.Combining the results of Z-scan and UV-Vis-NIR experiments,it can be speculated that moderate ground-state absorption,rather than excessively strong absorption,favors superior RSA properties.This work offers valuable insights for designing copolymers with excellent RSA behavior,as well as presents a class of candidate material systems for ultrabroadband optical limiting.展开更多
To enhance power flow regulation in scenarios involving large-scale renewable energy transmission via high-voltage direct current(HVDC)links and multi-infeed DC systems in load-center regions,this paper proposes a hyb...To enhance power flow regulation in scenarios involving large-scale renewable energy transmission via high-voltage direct current(HVDC)links and multi-infeed DC systems in load-center regions,this paper proposes a hybrid modular multilevel converter–capacitor-commutated line-commutated converter(MMC-CLCC)HVDC transmission system and its corresponding control strategy.First,the system topology is constructed,and a submodule configuration method for the MMC—combining full-bridge submodules(FBSMs)and half-bridge submodules(HBSMs)—is proposed to enable direct power flow reversal.Second,a hierarchical control strategy is introduced,includingMMCvoltage control,CLCC current control,and a coordinationmechanism,along with the derivation of the hybrid system’s power flow reversal characteristics.Third,leveraging the CLCC’s fast current regulation and theMMC’s negative voltage control capability,a coordinated power flow reversal control strategy is developed.Finally,an 800 kV MMC-CLCC hybrid HVDC system is modeled in PSCAD/EMTDC to validate the power flow reversal performance under a high proportion of full-bridge submodule configuration.Results demonstrate that the proposed control strategy enables rapid(1-s transition)and smooth switching of bidirectional power flow without modifying the structure of primary equipment:the transient fluctuation ofDC voltage from the rated value(UdcN)to themaximumreverse voltage(-kUdcN)is less than 5%;the DC current strictly follows the preset characteristic curve with a deviation of≤3%;the active power reverses continuously,and the system maintains stable operation throughout the reversal process.展开更多
Unmanned Aerial Vehicle(UAV)assisted federated learning enables on-edge model training,but its effectiveness depends on sustainable client participation through well-designed incentive mechanisms.Existing approaches b...Unmanned Aerial Vehicle(UAV)assisted federated learning enables on-edge model training,but its effectiveness depends on sustainable client participation through well-designed incentive mechanisms.Existing approaches based on economic models provide theoretical guarantees under restrictive assumptions,while Reinforcement Learning(RL)methods adapt to dynamics but lack provable incentive compatibility.We propose an adaptive privacy-aware incentive mechanism that integrates contract theory with Multi-Agent RL(MARL).The contract design provides a truthful initialization under privacy heterogeneity,while MARL adaptively refines incentives in dynamic environments.An Incentive Compatibility(IC)regularized optimization further ensures policy convergence and robustness.Experiments in UAV-assisted FL show that our method improves social welfare by up to 35%and participant engagement by 45%over state-of-the-art baselines,while maintaining strong privacy guarantees.展开更多
The 193 nm deep-ultraviolet(DUV)laser plays a critical role in advanced semiconductor chip manufacturing[1,2],micro-nano material characterization[3,4]and biomedical analysis[5,6],due to its high spatial resolution an...The 193 nm deep-ultraviolet(DUV)laser plays a critical role in advanced semiconductor chip manufacturing[1,2],micro-nano material characterization[3,4]and biomedical analysis[5,6],due to its high spatial resolution and short wavelength.Efficient and compact 193 nm DUV laser source thus becomes a hot research area.Currently,193 nm Ar F excimer gas laser is widely employed in DUV lithography systems and serves as the enabling technology for 7 and 5 nm semiconductor fabrication.展开更多
The spatially-resolved laser-based high resolution angle resolved photoemission spectroscopy(ARPES)measurements have been performed on the optimally-doped HgBa_(2)Ca_(2)Cu_(3)O_(8+δ)(Hg1223)superconductor with a T_(c...The spatially-resolved laser-based high resolution angle resolved photoemission spectroscopy(ARPES)measurements have been performed on the optimally-doped HgBa_(2)Ca_(2)Cu_(3)O_(8+δ)(Hg1223)superconductor with a T_(c) of 133 K.Two distinct regions are identified on the cleaved surface:the single Fermi surface region where only one Fermi surface is observed,and the double Fermi surface region where two Fermi surface sheets are resolved coming from both the inner(IP)and outer(OP)CuO_(2) planes.The electronic structure and superconducting gap are measured on both of these two regions.In both cases,the observed electronic states are mainly concentrated near the nodal region.The momentum dependence of the superconducting gap deviates from the standard d-wave form.These results indicate that the surface electronic structure of Hg1223 behaves more like that of underdoped cuprates.展开更多
Photoelectrochemical CO_(2)reduction to multi-carbon products fuels remains challenged by inefficient C–C coupling and competing proton reduction reaction.Herein,we designed a cationic covalent organic framework(COF+...Photoelectrochemical CO_(2)reduction to multi-carbon products fuels remains challenged by inefficient C–C coupling and competing proton reduction reaction.Herein,we designed a cationic covalent organic framework(COF+)to create an electrostatic microenvironment that synergizes with CuPt alloy nanoparticles for selective ethylene/ethane production.By spatially decoupling CO_(2)enrichment from proton exclusion,the COF^(+)/CuPt interface simultaneously facilitates CO_(2)accessibility while impeding H+migration,suppressing the hydrogen evolution reaction(HER).This unique microenvironment stabilizes key anionic intermediates(*COO^(−),*OCCO^(−))and promotes*CO dimerization,steering electron transfer toward C–C coupling.The optimized system achieves a record-high Faradaic efficiency of 51.5%±5.3%for ethane and 10.6%±2.5%for ethylene with a total C2+yield exceeding 62%at−0.25 V vs.RHE and high stability(>300 min),representing the highest performance for photoelectrochemical CO_(2)reduction to ethane.The combined analyses of in situ spectroscopy and theoretical calculations reveal that electrostatic field effects lower the energy barrier for*OCCO formation while accelerating hydrogenation kinetics.Therefore,this work demonstrates that microenvironment modification of the active site by cationic covalent organic framework is a versatile strategy for solar-driven CO_(2)conversion into value-added hydrocarbons.展开更多
Online Public Opinion Reports consolidate news and social media for timely crisis management by governments and enterprises.While large language models(LLMs)enable automated report generation,this specific domain lack...Online Public Opinion Reports consolidate news and social media for timely crisis management by governments and enterprises.While large language models(LLMs)enable automated report generation,this specific domain lacks formal task definitions and corresponding benchmarks.To bridge this gap,we define the Automated Online Public Opinion Report Generation(OPOR-Gen)task and construct OPOR-Bench,an event-centric dataset with 463 crisis events across 108 countries(comprising 8.8 K news articles and 185 K tweets).To evaluate report quality,we propose OPOR-Eval,a novel agent-based framework that simulates human expert evaluation.Validation experiments show OPOR-Eval achieves a high Spearman’s correlation(ρ=0.70)with human judgments,though challenges in temporal reasoning persist.This work establishes an initial foundation for advancing automated public opinion reporting research.展开更多
The application of poly(butylene adipate-co-terephthalate)(PBAT)biodegradable plastics has long been constrained by insufficient light aging resistance.Hindered amine light stabilizers(HALSs),known as eco-friendly add...The application of poly(butylene adipate-co-terephthalate)(PBAT)biodegradable plastics has long been constrained by insufficient light aging resistance.Hindered amine light stabilizers(HALSs),known as eco-friendly additives,can scavenge free radicals to enhance polymer durability.However,rough choices have resulted in wastage of resources and environmental pressure.Based on the application of plastic films as the background for use,this study systematically evaluates application effects of five HALSs.The films underwent accelerated aging for various durations and were further investigated by a combination of experiments and molecular simulation.Results showed that all HALSs mitigated PBAT light aging,with Chimassorb-944(UV-944)and Tinuvin-770(UV-770)performing the best for real applications.Quantum chemical calculation results showed that UV-944 had stronger anti migration ability.After 300 h of aging,films with UV-944 and UV-770 retained superior tensile strength and elongation at break in the transverse direction compared to neat PBAT films.Polymeric HALSs provided better long-term stability than small-molecule ones.Further spectra analysis indicated that stronger C―O bonds in HALS/PBAT composites correlated with improved photostability.This study offers valuable insights into improving weather resistance of PBAT biodegradable films and optimizing the real application of HALSs.展开更多
Sixty students from both genders aged 19 - 22 years old at College of Technology undertaking halfterm exams of 2012-2013 are encountered in this study. Blood samples were collected twice, i.e. before the exam inside t...Sixty students from both genders aged 19 - 22 years old at College of Technology undertaking halfterm exams of 2012-2013 are encountered in this study. Blood samples were collected twice, i.e. before the exam inside the halls and during the rest time, to compare levels of some hormones, e.g. cortisol from all students, testosterone in male only and both estrogen and progesterone in female students. The female group was further subdivided into two subgroups, 15 each i.e. at the first half of the menstrual cycle (follicular phase) and second group at the second half of the menstrual cycle (luteal phase). The levels of cortisol had significantly (p ≤ 0.05) raised from 12.3 ± 3.6 to 32.3 ± 4.2 ng/mL and from 11.6 ± 1.8 to 31.6 ± 7.3 ng/mL in both male and female students, respectively during exams in comparison with rest times. However, the levels of testosterone had significantly dropped (p ≤ 0.05) from 6.63 ± 1.8 to 2.1 ± 0.4 ng/mL during the test-time. In female students, the levels of both estrogens and progesterone had significantly (p ≤ 0.05) increased, i.e. in follicular from 202 ± 38 to 365 ± 22 and from 64.6 ± 8.0 to 160 ± 37 ng/mL at luteal phases, respectively and from 0.74 ± 0.03 to 1.5 ± 0.04 in follicular and 14.4 ± 2.4 to 29 ± 4.2 ng/mL at luteal phase, respectively in progesterone during the exam in comparison with rest times. These results indicate that all students had sustained stress during the exam-time which might have disturbed the regulation of various hormones in both genders consequently leading to further health effects.展开更多
Vector of diagnostic signs(VDS)using torsional vibration(TV)signal on the main propulsion plant(MPP)is the vector of z maxima(or minima)values of the TV signal in accordance with the cylinder firing orders.The technic...Vector of diagnostic signs(VDS)using torsional vibration(TV)signal on the main propulsion plant(MPP)is the vector of z maxima(or minima)values of the TV signal in accordance with the cylinder firing orders.The technical states of the marine diesel engine(MDE)include R=z+1 classes and are presented in z-dimensional space coordinate of VDS.The presentation of Dk,k=1÷R using z diagnostic signs(Vi,i=1÷z)is nonfigurative and quite complicated.This paper aims to develop a new method for converting VDS from z-dimensional to 2-dimensional space(two-axes)based on the firing orders of the diesel cylinders,as an equivalent geometrical sign of the all diagnostic signs.The proposed model is useful for presenting a technical state Dk in two-dimensional space(x,y)for better visualization.The paper verifies the simulation of the classification illustration of the 7–state classes for the MDE 6S46-MCC,installed on the motor vessel(MV)34000DWT,using the new above mentioned method.The seven technical state classes(for 6-cylinder MDE,z=6)are drawn separately and visually in the Descartes.The received results are valuable to improve smart diagnostic system for analyzing normal/misfire states of cylinders in operation regimes.展开更多
In order to explore the mechanism of improving the surface wettability of low-energy polytetrafluoroethylene(PTFE)by new extended surfactants,five kinds of extended anionic surfactants with different numbers of oxypro...In order to explore the mechanism of improving the surface wettability of low-energy polytetrafluoroethylene(PTFE)by new extended surfactants,five kinds of extended anionic surfactants with different numbers of oxypropylene(PO)and oxyethylene(EO),octadecyl-(PO)_(m)-(EO)_(n)-sodium carboxylate(C_(18)PO_(m)EO_(n)C,m=5,10,15,n=5,10,15),were studied.The surface tension and contact angle of C_(18)PO_(m)EO_(n)C solution with different concentrations were measured,and the adhesion tension,PTFE-water interfacial tension,and adhesion work were calculated.It was found that the extended surfactant molecules adsorb on the surface of the solution and the PTFE-liquid interface simultaneously when the concentration is lower than the critical micelle concentration(cmc),and there was a linear relationship between surface tension and adhesion tension.The adsorption amount of C_(18)PO_(m)EO_(n)C at the PTFE-water interface was significantly lower than that on the surface of the solution.As the concentration increases above cmc,semi-micelle aggregates on the surface of PTFE are formed by C_(18)PO_(m)EO_(n)C molecules through hydrophobic interaction,and the hydrophilic group faces the solution to modify the surface of PTFE with high efficiency.展开更多
Utilizing superwettability micro/nanostructures to enhance the condensation heat transfer(CHT)performance of engineering materials has attracted great interest due to its values in basic research and technological inn...Utilizing superwettability micro/nanostructures to enhance the condensation heat transfer(CHT)performance of engineering materials has attracted great interest due to its values in basic research and technological innovations.Currently,exploring facile micro/nanofabrication approaches to create high-efficiency CHT surfaces has been one of research hotspots.In this work,we propose and demonstrate a type of new superwettability hybrid surface for high-efficiency CHT,which consists of superhydrophobic nanoneedle arrays and triangularly-patterned superhydrophilic microdots(SMDs).Such hybrid surface can be fabricated by the facile growth of densely-packed ZnO nanoneedles on the Zn-electroplated copper surface followed by fluorosilane modification and mask-assisted photodegradation.Through regulating the diameters and interspaces of SMDs,we obtain the optimized triangularly-patterned hybrid surface,which shows 42.7%higher CHT coefficient than the squarely-patterned hybrid surface and 58.5%higher CHT coefficient than the superhydrophobic surface.The key of such hybrid surface design is to considerably increase CHT coefficient brought about by SMD-triggered drop sweeping at the cost of slightly reducing heat transfer area of superhydrophobic functional zone for drop jumping.Such new strategy helps develop advanced CHT surfaces for high-efficiency electronic cooling and energy utilization.展开更多
基金financial support of the National Key R&D Program of China(Grant Nos.2024YFB4607402 and 2016YFA0200500)National Natural Science Foundation of China(NSFC,Grant Nos.61975213,61475164 and 61205194)International Partnership Program of Chinese Academy of Sciences(GJHZ2021130)。
文摘Microrobots play an essential role in early diagnosis and precision medicine with the increasing demands for controllability in bio-medicine and micromanipulation,which can complete the pre-designed behavior under external stimulation.However,most microrobots are currently made of a single material system and focus on fabricating a driving module as the main structure of microrobots.This hinders the integration of diverse functions in one microrobot to fulfill the complex application.Here,a multi-material and multi-module hand-microrobot based on femtosecond laser direct writing technology is proposed,which has a pH-responsive capturing module and a magnetic-responsive transportation module(MRTM).This microrobot can not only respond to pH for capturing and releasing objects,but also respond to magnetic fields for cargo delivery even with obstacles.The two responding modules of the hand-microrobot are fabricated independently,and can collaborate with each other to achieve the delivery of target objects like polystyrene(PS)microsphere(10µm)or 786-O cell by capturing,transporting,and spatial rolling.Besides,the MRTM can be locally fabricated on any prefabricated static structure,so that the whole microrobot can achieve controllable motion.This strategy is expected to be used to manipulate cells,deliver drugs for precise treatment,and environmental treatment.
文摘Biomass-derived carbon materials are favored for their abundance and sustainability,and ease of preparation and modification.By surface activation and modification they can have a good electrical conductivity,excellent catalytic activity,a remarkable adsorption capacity,and different interfacial physicochemical functionalities.Surface-modified biochars have found wide applications in energy storage,environmental remediation,and catalysis.However,achieving precise and controllable modification of their active sites remains a challenge.Recent advances and future prospects for controlling their surface morphology,defect engineering,and surface coating strategies,with particular attention to their means of fabrication,are reviewed.
文摘Nickel-catalyzed borylation of aryl nonaflates with B2pin2 could be realized,which proceeded effectively by means of C—O bond functionalization to afford a wide variety of valuable arylboronates in moderate to excellent yields with good functionality compatibility.In addition,the gram-scale synthesis and the application of the approach in the late-stage elaboration of aryl nonaflate derived from pterostilbene could also be achieved.
文摘In this study,sawdust served as a carbon source and urea as a nitrogen source to synthesize carbonsupported,nitrogen-doped TiO_(2)composites via a one-pot solvothermal method.The composites were characterized using FTIR,powder X-ray diffraction,X-ray photoelectron spectroscopy,ultraviolet-visible diffuse reflectance spectroscopy,thermogravimetry-derivative thermogravimetry,scanning electron microscopy-energy dispersive spectroscopy,and transmission electron microscopy.Results indicated that all synthesized composites exhibit the anatase phase,with those calcined at 800℃ demonstrating enhanced crystallinity.Nitrogen is incorporated into the TiO_(2)lattice,while carbon is predominantly located on the surface.Photodegradation experiments showed that 20 mg of composite N-TiO_(2)/C-800 achieved degradation rates of 93.4% for methylene blue(20 mg·L^(-1),50 mL)and 99.4% for oxytetracycline(20 mg·L^(-1),50 mL)within 30 min.Free radical capture experiments indicated that h+was the primary active species in the photocatalytic degradation process.
文摘In modern industrial production,foreign object detection in complex environments is crucial to ensure product quality and production safety.Detection systems based on deep-learning image processing algorithms often face challenges with handling high-resolution images and achieving accurate detection against complex backgrounds.To address these issues,this study employs the PatchCore unsupervised anomaly detection algorithm combined with data augmentation techniques to enhance the system’s generalization capability across varying lighting conditions,viewing angles,and object scales.The proposed method is evaluated in a complex industrial detection scenario involving the bogie of an electric multiple unit(EMU).A dataset consisting of complex backgrounds,diverse lighting conditions,and multiple viewing angles is constructed to validate the performance of the detection system in real industrial environments.Experimental results show that the proposed model achieves an average area under the receiver operating characteristic curve(AUROC)of 0.92 and an average F1 score of 0.85.Combined with data augmentation,the proposed model exhibits improvements in AUROC by 0.06 and F1 score by 0.03,demonstrating enhanced accuracy and robustness for foreign object detection in complex industrial settings.In addition,the effects of key factors on detection performance are systematically analyzed,providing practical guidance for parameter selection in real industrial applications.
基金supported by the National Key Research and Devel-opment Program of China(2022YFA1205500)the National Natural Science Foundation of China(22174159)+2 种基金and the Key Research Project of Chinese Academy of Sciences under Grant Number.KGFZD-145-25-21-01,the Tianshan Talents Plan(2022TSYCCX0074)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(2022441)the Natural Science Foundation of Xinjiang Uygur Autonomous Region(2025D01E54).
文摘The design of zero-background fluorescent sensing materials with specific functionalities is of great significance.Here,a special Eu-MOF with nonfluorescent emission was designed and driven by H_(2)O-induced cascade reaction through modulating the number of hydroxyl groups in ligands to enhance the signal-to-noise ratio,sensitivity,and reaction speed toward triacetone triperoxide(TATP).It is found that only when the ligand was selected as 2,5-dihydroxyterephthalic acid(DHTA),and with the introduction of H_(2)O,the intramolecular hydrogen bond could be changed to a weaker intermolecular hydrogen bond,which would be interrupted and oxidized from the original enol structure to ketone,producing the fluorescence turn-on response toward TATP.The special Eu-MOF exhibited a high-performance sensing for TATP,with fast response(<1 s),low limit of detection(LOD,36.1 nM),superior selectivity even in the presence of 28 kinds of interferents,including the very similar hydrogen peroxide,strong robustness,and a practical detecting ability of 5 pg airborne TATP particle.Furthermore,we validated the practical feasibility of the specific Eu-MOF by integrating a sensing chip into a portable detector,thereby confirming that this MOF exhibits considerable potential for trace-level TATP detection in real-world application scenarios.The present nonfluorescent MOF design strategy and the elaborate modulation of the conformation in MOF structure would provide a new pathway for the exploration of novel functional MOFs as well as high-performance sensing methodologies.
基金financially supported by the National Natural Science Foundation of China(No.52073294)National Key R&D Program of China(No.2021YFB4000700)+1 种基金Project of Stable Support for Youth Team in Basic Research Field of the Chinese Academy of Sciences,China(No.YSBR-017)The authors are highly grateful to Mr.Fan-Ming Zhao for Cryogenic Mechanical Testing.
文摘With the development of electronic technologies,piezoresistive sensors have attracted increasing attention.Among them,aerogels with high elasticity,as a type of three-dimensional porous material,are widely used in the field of piezoresistive sensors.Nowadays,with the extension of science and technology areas,fields involving low-temperature environments have emerged,which has led to an increasing demand for piezoresistive sensors that can serve at cryogenic temperatures.However,most studies on aerogels have only focused on their sensing performance at room temperature,and there is a lack of research on aerogel sensors that can work at low temperatures.In this work,piezoresistive sensors based on cotton fibers were proposed for applications at 77 K.As one of the most important natural polymers,cotton fibers have the ability to maintain elasticity at very low temperatures.Cotton fiber-based aerogels with high elasticity and cyclic stability were obtained by controlling the freeze-casting parameters and size distribution of cotton fibers,and they showed excellent pressure sensing properties,including a wide sensing range and remarkable long-term stability.This study bridges the gap in cryogenic sensing materials and provides insights into microstructure-property relationships,advancing applications in aerospace and cryogenic engineering.
基金financially supported by the National Key Research and Development Program of China(Nos.2024YFB4607402 and 2016YFC1100502)the National Natural Science Foundation of China(Nos.51673208 and 61975213)。
文摘Biopolymeric nanocomposites have attracted considerable attention because of their biocompatibility,biodegradability,and unique physicochemical properties.It is essential to manufacture three-dimensional(3D)biocompatible micro/nanostructures using biopolymeric nanocomposites.Herein,we demonstrate the high-fidelity fabrication of biocompatible 3D features with sub-50 nm resolution using femtosecond laser direct writing(FsLDW)of a biopolymeric nanocomposite composed of egg white and sulfonated graphene(S-graphene).The biopolymer nanocomposite acts as a negative photoresist suitable for water-based lithography.The introduction of S-graphene not only dramatically lowered the laser power threshold but also significantly modulated the morphology of the 3D features constructed by FsLDW.Microstructures with porous,rough,or smooth morphologies were obtained by optimizing the S-graphene concentration and laser scanning speed.The fabricated egg-white/S-graphene microstructures exhibited biocompatibility and environmental degradability.Egg white/S-graphene was also employed to fabricate diffractive gratings with superior optical quality.This study provides a promising method to manufacture biocompatible 3D features with controllable morphology,which has potential applications in biological and photonic fields.
基金supported by the National Natural Science Foundation of China(No.52102013)。
文摘Construction of electron donor-acceptor(D-A)conjugated system is an established strategy for achieving reverse saturable absorption(RSA)and broadband optical limiting(OL).Nevertheless,organic materials exhibit OL ability across the visible to near-infrared-II spectra range remain scarce.Herein,a series of D-A typeπ-conjugated copolymers with ultra-narrow bandgaps(0.62-0.76 e V)and strong ICT absorption were synthesized by coupling electron-withdrawing block[1,2,5]thiadiazolo[3,4-g]quinoxaline(TQ)with various electron-donating groups(thiophene,selenophene,bithiophene,di(thiophen-2-yl)ethene,and thienothiophene for P1-P5,respectively).Z-scan experiments reveal that all copolymers exhibit RSA behaviours at both 532 and 1064 nm,while P1,P3 and P4 maintain RSA performance extending to 1600 nm.Among all copolymers,P5 exhibits the strongest RSA performance upon both 532 and 1064 nm laser pulses,with the highest nonlinear absorption coefficient(β_(eff))of 51.5 and 49.4 cm·GW^(-1),respectively,and the lowest OL onset fluence(Fon)of 0.31 and 0.38 J·cm^(-2),respectively.In contrast,P4 shows optimal RSA property at 1600 nm laser pulse,withβeff of 13.1 cm·GW^(-1)and Fon of 1.43 J·cm^(-2),respectively.Combining the results of Z-scan and UV-Vis-NIR experiments,it can be speculated that moderate ground-state absorption,rather than excessively strong absorption,favors superior RSA properties.This work offers valuable insights for designing copolymers with excellent RSA behavior,as well as presents a class of candidate material systems for ultrabroadband optical limiting.
基金supported by Science and Technology Project of the headquarters of the State Grid Corporation of China(No.5500-202324492A-3-2-ZN).
文摘To enhance power flow regulation in scenarios involving large-scale renewable energy transmission via high-voltage direct current(HVDC)links and multi-infeed DC systems in load-center regions,this paper proposes a hybrid modular multilevel converter–capacitor-commutated line-commutated converter(MMC-CLCC)HVDC transmission system and its corresponding control strategy.First,the system topology is constructed,and a submodule configuration method for the MMC—combining full-bridge submodules(FBSMs)and half-bridge submodules(HBSMs)—is proposed to enable direct power flow reversal.Second,a hierarchical control strategy is introduced,includingMMCvoltage control,CLCC current control,and a coordinationmechanism,along with the derivation of the hybrid system’s power flow reversal characteristics.Third,leveraging the CLCC’s fast current regulation and theMMC’s negative voltage control capability,a coordinated power flow reversal control strategy is developed.Finally,an 800 kV MMC-CLCC hybrid HVDC system is modeled in PSCAD/EMTDC to validate the power flow reversal performance under a high proportion of full-bridge submodule configuration.Results demonstrate that the proposed control strategy enables rapid(1-s transition)and smooth switching of bidirectional power flow without modifying the structure of primary equipment:the transient fluctuation ofDC voltage from the rated value(UdcN)to themaximumreverse voltage(-kUdcN)is less than 5%;the DC current strictly follows the preset characteristic curve with a deviation of≤3%;the active power reverses continuously,and the system maintains stable operation throughout the reversal process.
基金supported by the National Natural Science Foundation of China(No.62361003)the Guangxi Science and Technology Base and Talent Special Project(Nos.AD25069071 and AD24010061).
文摘Unmanned Aerial Vehicle(UAV)assisted federated learning enables on-edge model training,but its effectiveness depends on sustainable client participation through well-designed incentive mechanisms.Existing approaches based on economic models provide theoretical guarantees under restrictive assumptions,while Reinforcement Learning(RL)methods adapt to dynamics but lack provable incentive compatibility.We propose an adaptive privacy-aware incentive mechanism that integrates contract theory with Multi-Agent RL(MARL).The contract design provides a truthful initialization under privacy heterogeneity,while MARL adaptively refines incentives in dynamic environments.An Incentive Compatibility(IC)regularized optimization further ensures policy convergence and robustness.Experiments in UAV-assisted FL show that our method improves social welfare by up to 35%and participant engagement by 45%over state-of-the-art baselines,while maintaining strong privacy guarantees.
基金supported by the National Natural Science Foundation of China(Grant Nos.62450006,62304217,62274157,62127807,62234011,62034008,62074142,62074140)Tianshan Innovation Team Program(Grant No.2022TSYCTD0005)+1 种基金Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB0880000)Youth Innovation Promotion Association of the Chinese Academy of Sciences(Grant Nos.2023124,Y2023032)。
文摘The 193 nm deep-ultraviolet(DUV)laser plays a critical role in advanced semiconductor chip manufacturing[1,2],micro-nano material characterization[3,4]and biomedical analysis[5,6],due to its high spatial resolution and short wavelength.Efficient and compact 193 nm DUV laser source thus becomes a hot research area.Currently,193 nm Ar F excimer gas laser is widely employed in DUV lithography systems and serves as the enabling technology for 7 and 5 nm semiconductor fabrication.
基金supported by the National Key Research and Development Program of China(Grant Nos.2021YFA1401800,2022YFA1604200,2022YFA1403900,2023YFA1406002,2024YFA1408301 and 2024YFA1408100)the National Natural Science Foun-dation of China(Grant Nos.12488201,12374066,12374154,12494593)+2 种基金Quantum Science and Technology-National Science and Technology Major Project(Grant No.2021ZD0301800)CAS Superconducting Research Project(Grant No.SCZX-0101)the Synergetic Extreme Condition User Facility(SECUF).
文摘The spatially-resolved laser-based high resolution angle resolved photoemission spectroscopy(ARPES)measurements have been performed on the optimally-doped HgBa_(2)Ca_(2)Cu_(3)O_(8+δ)(Hg1223)superconductor with a T_(c) of 133 K.Two distinct regions are identified on the cleaved surface:the single Fermi surface region where only one Fermi surface is observed,and the double Fermi surface region where two Fermi surface sheets are resolved coming from both the inner(IP)and outer(OP)CuO_(2) planes.The electronic structure and superconducting gap are measured on both of these two regions.In both cases,the observed electronic states are mainly concentrated near the nodal region.The momentum dependence of the superconducting gap deviates from the standard d-wave form.These results indicate that the surface electronic structure of Hg1223 behaves more like that of underdoped cuprates.
基金financial support from the National Natural Science Foundation of China(No.52273187)the Guangdong Basic and Applied Basic Research Foundation(2022A1515110372,2023A1515011306,2023A1515240077)+1 种基金the National Key Research and Development Program of China(2022YFA1502900)the Guangdong-Hong Kong Joint Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong Province(2023B1212120011).
文摘Photoelectrochemical CO_(2)reduction to multi-carbon products fuels remains challenged by inefficient C–C coupling and competing proton reduction reaction.Herein,we designed a cationic covalent organic framework(COF+)to create an electrostatic microenvironment that synergizes with CuPt alloy nanoparticles for selective ethylene/ethane production.By spatially decoupling CO_(2)enrichment from proton exclusion,the COF^(+)/CuPt interface simultaneously facilitates CO_(2)accessibility while impeding H+migration,suppressing the hydrogen evolution reaction(HER).This unique microenvironment stabilizes key anionic intermediates(*COO^(−),*OCCO^(−))and promotes*CO dimerization,steering electron transfer toward C–C coupling.The optimized system achieves a record-high Faradaic efficiency of 51.5%±5.3%for ethane and 10.6%±2.5%for ethylene with a total C2+yield exceeding 62%at−0.25 V vs.RHE and high stability(>300 min),representing the highest performance for photoelectrochemical CO_(2)reduction to ethane.The combined analyses of in situ spectroscopy and theoretical calculations reveal that electrostatic field effects lower the energy barrier for*OCCO formation while accelerating hydrogenation kinetics.Therefore,this work demonstrates that microenvironment modification of the active site by cationic covalent organic framework is a versatile strategy for solar-driven CO_(2)conversion into value-added hydrocarbons.
基金supported by the Fundamental Research Funds for the Central Universities(No.CUC25SG013)the Foundation of Key Laboratory of Education Informatization for Nationalities(Yunnan Normal University),Ministry of Education(No.EIN2024C006).
文摘Online Public Opinion Reports consolidate news and social media for timely crisis management by governments and enterprises.While large language models(LLMs)enable automated report generation,this specific domain lacks formal task definitions and corresponding benchmarks.To bridge this gap,we define the Automated Online Public Opinion Report Generation(OPOR-Gen)task and construct OPOR-Bench,an event-centric dataset with 463 crisis events across 108 countries(comprising 8.8 K news articles and 185 K tweets).To evaluate report quality,we propose OPOR-Eval,a novel agent-based framework that simulates human expert evaluation.Validation experiments show OPOR-Eval achieves a high Spearman’s correlation(ρ=0.70)with human judgments,though challenges in temporal reasoning persist.This work establishes an initial foundation for advancing automated public opinion reporting research.
基金supported by the Key Research and Development Task Project of Xinjiang Uygur Autonomous Region(No.2022B02033)the National Natural Science Foundation of China(Nos.42211530566 and 42311530066)+2 种基金the NSFC-FNRS Joint Program BIOAGRIFILM(No.FNRS PINT-BILATM 2022)the Science and Technology Project of Bijie Tobacco Company of Guizhou Province(No.2022520500240192)the Agricultural Science and Technology Innovation Program(ASTIP)。
文摘The application of poly(butylene adipate-co-terephthalate)(PBAT)biodegradable plastics has long been constrained by insufficient light aging resistance.Hindered amine light stabilizers(HALSs),known as eco-friendly additives,can scavenge free radicals to enhance polymer durability.However,rough choices have resulted in wastage of resources and environmental pressure.Based on the application of plastic films as the background for use,this study systematically evaluates application effects of five HALSs.The films underwent accelerated aging for various durations and were further investigated by a combination of experiments and molecular simulation.Results showed that all HALSs mitigated PBAT light aging,with Chimassorb-944(UV-944)and Tinuvin-770(UV-770)performing the best for real applications.Quantum chemical calculation results showed that UV-944 had stronger anti migration ability.After 300 h of aging,films with UV-944 and UV-770 retained superior tensile strength and elongation at break in the transverse direction compared to neat PBAT films.Polymeric HALSs provided better long-term stability than small-molecule ones.Further spectra analysis indicated that stronger C―O bonds in HALS/PBAT composites correlated with improved photostability.This study offers valuable insights into improving weather resistance of PBAT biodegradable films and optimizing the real application of HALSs.
文摘Sixty students from both genders aged 19 - 22 years old at College of Technology undertaking halfterm exams of 2012-2013 are encountered in this study. Blood samples were collected twice, i.e. before the exam inside the halls and during the rest time, to compare levels of some hormones, e.g. cortisol from all students, testosterone in male only and both estrogen and progesterone in female students. The female group was further subdivided into two subgroups, 15 each i.e. at the first half of the menstrual cycle (follicular phase) and second group at the second half of the menstrual cycle (luteal phase). The levels of cortisol had significantly (p ≤ 0.05) raised from 12.3 ± 3.6 to 32.3 ± 4.2 ng/mL and from 11.6 ± 1.8 to 31.6 ± 7.3 ng/mL in both male and female students, respectively during exams in comparison with rest times. However, the levels of testosterone had significantly dropped (p ≤ 0.05) from 6.63 ± 1.8 to 2.1 ± 0.4 ng/mL during the test-time. In female students, the levels of both estrogens and progesterone had significantly (p ≤ 0.05) increased, i.e. in follicular from 202 ± 38 to 365 ± 22 and from 64.6 ± 8.0 to 160 ± 37 ng/mL at luteal phases, respectively and from 0.74 ± 0.03 to 1.5 ± 0.04 in follicular and 14.4 ± 2.4 to 29 ± 4.2 ng/mL at luteal phase, respectively in progesterone during the exam in comparison with rest times. These results indicate that all students had sustained stress during the exam-time which might have disturbed the regulation of various hormones in both genders consequently leading to further health effects.
文摘Vector of diagnostic signs(VDS)using torsional vibration(TV)signal on the main propulsion plant(MPP)is the vector of z maxima(or minima)values of the TV signal in accordance with the cylinder firing orders.The technical states of the marine diesel engine(MDE)include R=z+1 classes and are presented in z-dimensional space coordinate of VDS.The presentation of Dk,k=1÷R using z diagnostic signs(Vi,i=1÷z)is nonfigurative and quite complicated.This paper aims to develop a new method for converting VDS from z-dimensional to 2-dimensional space(two-axes)based on the firing orders of the diesel cylinders,as an equivalent geometrical sign of the all diagnostic signs.The proposed model is useful for presenting a technical state Dk in two-dimensional space(x,y)for better visualization.The paper verifies the simulation of the classification illustration of the 7–state classes for the MDE 6S46-MCC,installed on the motor vessel(MV)34000DWT,using the new above mentioned method.The seven technical state classes(for 6-cylinder MDE,z=6)are drawn separately and visually in the Descartes.The received results are valuable to improve smart diagnostic system for analyzing normal/misfire states of cylinders in operation regimes.
文摘In order to explore the mechanism of improving the surface wettability of low-energy polytetrafluoroethylene(PTFE)by new extended surfactants,five kinds of extended anionic surfactants with different numbers of oxypropylene(PO)and oxyethylene(EO),octadecyl-(PO)_(m)-(EO)_(n)-sodium carboxylate(C_(18)PO_(m)EO_(n)C,m=5,10,15,n=5,10,15),were studied.The surface tension and contact angle of C_(18)PO_(m)EO_(n)C solution with different concentrations were measured,and the adhesion tension,PTFE-water interfacial tension,and adhesion work were calculated.It was found that the extended surfactant molecules adsorb on the surface of the solution and the PTFE-liquid interface simultaneously when the concentration is lower than the critical micelle concentration(cmc),and there was a linear relationship between surface tension and adhesion tension.The adsorption amount of C_(18)PO_(m)EO_(n)C at the PTFE-water interface was significantly lower than that on the surface of the solution.As the concentration increases above cmc,semi-micelle aggregates on the surface of PTFE are formed by C_(18)PO_(m)EO_(n)C molecules through hydrophobic interaction,and the hydrophilic group faces the solution to modify the surface of PTFE with high efficiency.
基金supported by National Natural Science Foundation of China(No.21573276)Natural Science Foundation of Jiangsu Province(No.BK20170007)Jiangsu Funding Program for Excellent Postdoctoral Talent(No.2022ZB846).
文摘Utilizing superwettability micro/nanostructures to enhance the condensation heat transfer(CHT)performance of engineering materials has attracted great interest due to its values in basic research and technological innovations.Currently,exploring facile micro/nanofabrication approaches to create high-efficiency CHT surfaces has been one of research hotspots.In this work,we propose and demonstrate a type of new superwettability hybrid surface for high-efficiency CHT,which consists of superhydrophobic nanoneedle arrays and triangularly-patterned superhydrophilic microdots(SMDs).Such hybrid surface can be fabricated by the facile growth of densely-packed ZnO nanoneedles on the Zn-electroplated copper surface followed by fluorosilane modification and mask-assisted photodegradation.Through regulating the diameters and interspaces of SMDs,we obtain the optimized triangularly-patterned hybrid surface,which shows 42.7%higher CHT coefficient than the squarely-patterned hybrid surface and 58.5%higher CHT coefficient than the superhydrophobic surface.The key of such hybrid surface design is to considerably increase CHT coefficient brought about by SMD-triggered drop sweeping at the cost of slightly reducing heat transfer area of superhydrophobic functional zone for drop jumping.Such new strategy helps develop advanced CHT surfaces for high-efficiency electronic cooling and energy utilization.
