Endowing stimuli-responsive materials with micro-nano structures is an intriguing strategy for the fabrication of superwetting surfaces;however,its application is limited by poor chemical/mechanical stability.Herein,a...Endowing stimuli-responsive materials with micro-nano structures is an intriguing strategy for the fabrication of superwetting surfaces;however,its application is limited by poor chemical/mechanical stability.Herein,a simple and versatile strategy was developed to fabricate durable polymeric superwetting surfaces with photoswitchable wettability on hierarchically structured metallic substrates.Inspired by nature,a novel functional terpolymer incorporating mussel-inspired catechol groups,photoresponsive azobenzene groups,and low-surface-energy fluorine-containing groups was synthesized via solution radical polymerization.The azobenzene-containing terpolymer possesses outstanding photoresponsiveness in both the solution and film states because of the trans-cis isomerization of the azobenzene moieties.After dip-coating with the mussel-inspired azo-copolymer,the as-prepared smart surfaces exhibited a photo-triggered change in wettability between high hydrophobicity and superhydrophilicity.More importantly,these superwetting surfaces with enhanced adhesion properties can tolerate harsh environmental conditions and repeated abrasion tests,thereby demonstrating excellent chemical robustness and mechanical durability.This study paves a new avenue for the convenient and large-scale fabrication of robust smart surfaces that could find widespread potential applications in microfluidic devices,water treatment,and functional coatings.展开更多
This work proposes a bioinspired hierarchical actuation strategy based on liquid crystal elastomers(LCEs),inspired by the helical topological dynamic adaptation mechanism of plant tendrils,to overcome the bottleneck o...This work proposes a bioinspired hierarchical actuation strategy based on liquid crystal elastomers(LCEs),inspired by the helical topological dynamic adaptation mechanism of plant tendrils,to overcome the bottleneck of precise anisotropic control in LCEs.Mechanically pre-programmed hierarchical LCE structures responsive to near-infrared(NIR)light were fabricated:the oriented constrained actuator achieves asymmetric contraction under NIR irradiation,enabling reversible switching between helix and planar morphologies with multi-terrain grasping capability;the biomimetic vine-like helical actuator,composed of Ag nanowire photothermal layers combined with helical LCE,utilizes temperaturegradient-induced phase transition wave propagation to achieve NIR-controlled climbing motion;the M?bius topology actuator realizes reversible deformation or self-locking states by tuning the twist angle(180°/360°);based on these,a bioinspired koala-like concentric soft robot was constructed,successfully demonstrating tree trunk climbing.This study reveals that artificial helical stretching significantly enhances the molecular chain orientation of LCEs(surpassing uniaxial stretching),reaching up to 1000%pre-strain,and the Ag NWs/LCE/PI(Polyimide)tri-layer structure achieves efficient photothermal-mechanical energy conversion via localized surface plasmon resonance(LSPR).This study provides a new paradigm for soft robotics material design and topological programming,demonstrating the potential for remote operation and adaptive grasping.展开更多
In the background of carbon neutrality,monolithic ceramic catalysts are universally used in energy conversion and chemical catalysis due to the high heat and mass transfer efficiencies,low bed pressures,and scalabilit...In the background of carbon neutrality,monolithic ceramic catalysts are universally used in energy conversion and chemical catalysis due to the high heat and mass transfer efficiencies,low bed pressures,and scalability through modular design.However,traditional manufacturing processes are limited by mold dependence,organic solvent toxicity,and insufficient molding capability for complex structures,resulting in difficulty achieving precise regulation of cross-scale pores.Additive manufacturing(AM)technology employs a digital layered molding strategy to achieve the cross-scale structural regulation of catalysts from macroscopic flow channels to mesopores and micropores.This paper summarizes recent advances in the structural design of monolithic catalysts enabled by AM technologies and highlights their emerging applications in catalytic processes.Structurally,AM-fabricated monoliths have been effectively employed in key chemical reactions such as fuel reforming,CO_(2)conversion,biofuel synthesis.Strategies such as geometrical topology optimization,multi-scale pore synergy,biomimetic structural design,and functional gradient integration have been utilized to enhance heat and mass transport,reduce pressure drops,and improve overall catalytic performance.By overcoming the limitations of traditional catalysts,AM technologies create a new paradigm for addressing the longstanding challenge of coupling mass transfer with reaction kinetics.This approach provides a feasible pathway for driving both theoretical innovation and practical implementation of high-efficiency catalytic systems.展开更多
The regulation of the interfacial electric field plays a pivotal role in magnifying the electromagnetic en-ergy attenuation capability during the design and synthesis of efficient and tunable absorbers for elec-tromag...The regulation of the interfacial electric field plays a pivotal role in magnifying the electromagnetic en-ergy attenuation capability during the design and synthesis of efficient and tunable absorbers for elec-tromagnetic waves(EMW).Herein,a rational and universally applicable two-step hydrothermal method strategy was proposed to effectively control the electronic structure of Mott-Schottky EMW absorbing materials derived from Co-MOF.The as-synthesized Co_(3)S_(4)@MoS_(2)/NC ensures efficient electron transfer,while the change redistribution leads to the emergence of additional electric dipoles under an external EMM field.In addition,the hierarchical Co_(3)S_(4)@MoS_(2)/NC nano-architecture with a hierarchical arrange-ment in 2D and 3D offers more polarization sites,thereby extending the path for EMW transmission through multiple reflections and scattering.The potential to enhance the EMW absorption performance of Co_(3)S_(4)@MoS_(2)/NC lies in its unique microstructure and substantial surface area,which optimize impedance matching properties through a synergistic effect of dipole and interfacial polarization induced by Mott-Schottky heterointerfaces.As anticipated,the Co_(3)S_(4)@MoS_(2)/NC exhibits a maximum EMW absorption ca-pacity with an RLmin value of-41.97 dB and a broad EAB of 4.24 GHz at a thickness of 2.0 mm.This study provides insights for designing highly efficient Mott-Schottky EMW absorbing materials at the molecular level rationally.展开更多
Hierarchical porous structure,which include macropores,minor pores,and micropores in scaffolds,are essential in the multiple biological functions of bone repair and regeneration.In this study,patientcustomized calcium...Hierarchical porous structure,which include macropores,minor pores,and micropores in scaffolds,are essential in the multiple biological functions of bone repair and regeneration.In this study,patientcustomized calcium-deficient hydroxyapatite(CDHA)scaffolds with three-level hierarchical porous structure were fabricated by indirect 3D printing technology and particulate leaching method.The sacrificial template scaffolds were fabricated using a photo-curing 3D printer,which provided a prerequisite for the integral structure and interconnected macropores of CDHA scaffolds.Additionally,20 wt%pore former was incorporated into the slurry to enhance the content of smaller pores within the CDHA-2 scaffolds,and then the CDHA-2 scaffolds were sintered to remove the sacrificial template scaffolds and pore former.The obtained CDHA-2 scaffolds exhibited interconnected macropores(300-400μm),minor pores(∼10-100μm),and micropores(<10μm)distributed throughout the scaffolds,which could promote bone tissue ingrowth,increase surface roughness,and enhance protein adsorption of scaffolds.In vitro studies identified that CDHA-2 scaffolds had nanocrystal grains,high specific surface area,and outstanding protein adsorption capacity,which could provide a microenvironment for cell adhesion,spreading,and proliferation.In addition,the murine intramuscular implantation experiment suggested that CDHA-2 scaffolds exhibited excellent osteoinductivity and were superior to traditional BCP ceramics under conditions without the addition of live cells and exogenous growth factors.The rabbit calvarial defect repair results indicated that CDHA-2 scaffolds could enhance in situ bone regeneration.In conclusion,these findings demonstrated that the hierarchical porous structure of CDHA scaffolds was a pivotal factor in modulating osteoinductivity and bone regeneration,and CDHA-2 scaffolds were potential candidates for bone regeneration.展开更多
Switchable radiative cooling/heating holds great promise for mitigating the global energy and environmental crisis.Here,we reported a cost-effective,high-strength Janus film through surface optical engineering waste p...Switchable radiative cooling/heating holds great promise for mitigating the global energy and environmental crisis.Here,we reported a cost-effective,high-strength Janus film through surface optical engineering waste paper with one side decorated by a hydrophobic polymeric cooling coating consisting of micro/nanopore/particle hierarchical structure and the other side coated with hydrophilic MXene nanosheets for heating.The cooling surface demonstrates high solar reflectivity(96.3%)and infrared emissivity(95.5%),resulting in daytime/nighttime sub-ambient radiative cooling of 6℃/8℃with the theoretical cooling power of 100.6 and 138.5Wm^(−2),respectively.The heating surface exhibits high solar absorptivity(83.7%)and low infrared emissivity(15.2%),resulting in excellent radiative heating capacity for vehicle charging pile(~6.2℃)and solar heating performance.Impressively,the mechanical strength of Janus film increased greatly by 563%compared with that of pristine waste paper,which is helpful for its practical applications in various scenarios for switchable radiative thermal management through mechanical flipping.Energy-saving simulation results reveal that significant total energy savings of up to 32.4MJm^(−2) can be achieved annually(corresponding to the 12.4%saving ratio),showing the immense importance of reducing carbon footprint and promoting carbon neutrality.展开更多
Hierarchical micro/nanograting structures have attracted increasing attention owing to their significant applications in the fields of structural coloring,anti-counterfeiting,and decoration.Thus,the fabrication of hie...Hierarchical micro/nanograting structures have attracted increasing attention owing to their significant applications in the fields of structural coloring,anti-counterfeiting,and decoration.Thus,the fabrication of hierarchical micro/nanograting structures is important for these applications.In this study,a strategy for machining hierarchical micro/nanograting structures is developed by controlling the tool movement trajectory.A coupling Euler-Lagrange finite element model is established to simulate the machining process.The effect of the machining methods on the nanograting formation is demonstrated,and a suitable machining method for reducing the cutting force is obtained.The height of the nanograting decreases with an increase in the tool edge radius.Furthermore,optical variable devices(OVDs)are machined using an array overlap machining approach.Coding schemes for the parallel column unit crossover and column unit in the groove crossover are designed to achieve high-quality machining of OVDs.The coloring of the logo of the Harbin Institute of Technology and the logo of the centennial anniversary of the Harbin Institute of Technology on the surface of metal samples,such as aluminum alloys,is realized.The findings of this study provide a method for the fabrication of hierarchical micro/nanograting structures that can be used to prepare OVDs.展开更多
Flower-like tin oxide-supported platinum（Pt/SnOx） with a hierarchical structure was synthesized by a hydrothermal method and characterized by XRD,SEM,TEM,high resolution TEM,XPS and nitrogen adsorption.The flower-li...Flower-like tin oxide-supported platinum（Pt/SnOx） with a hierarchical structure was synthesized by a hydrothermal method and characterized by XRD,SEM,TEM,high resolution TEM,XPS and nitrogen adsorption.The flower-like Pt/SnOx microspheres of 1 μm in diameter were composed of staggered petal-like nanosheets with a thickness of 20 nm.Pt nanoparticles（NPs） of 2-3 nm were well dispersed on the SnOx nanosheets.The catalyst was tested in the catalytic oxidation of gaseous formaldehyde（HCHO） at room temperature,and exhibited enhanced activity compared to Pt NPs supported on commercial SnO and ground SnOx.HCHO removal of 87%was achieved over the hierarchical Pt/SnOx after 1 h of reaction,which was 1.5 times that over the ground SnOx-supported Pt（Pt/g-SnOx）,and the high activity was maintained after six recycles,showing the high stability of this catalyst.HCHO decomposition kinetics was modeled as a second order reaction.The reaction rate constant for Pt/SnOx was 5.6 times higher than Pt/g-SnOx.The hierarchical pore structure was beneficial for the diffusion and adsorption of HCHO molecules,and the highly dispersed Pt NPs on the SnOx nanosheets were the active sites for the oxidative decomposition of HCHO into CO2 and H2O.This study provided a promising approach for designing efficient catalysts for indoor HCHO removal at ambient temperature.展开更多
Transition-metal nitrides exhibit wide potential windows and good electrochemical performance, but usually experience imbalanced practical applications in the energy storage field due to aggregation, poor circulation ...Transition-metal nitrides exhibit wide potential windows and good electrochemical performance, but usually experience imbalanced practical applications in the energy storage field due to aggregation, poor circulation stability, and complicated syntheses. In this study, a novel and simple multiphase polymeric strategy was developed to fabricate hybrid vanadium nitride/carbon(VN/C) membranes for supercapacitor negative electrodes, in which VN nanoparticles were uniformly distributed in the hierarchical porous carbon 3D networks. The supercapacitor negative electrode based on VN/C membranes exhibited a high specific capacitance of 392.0 F g^(-1) at 0.5 A g^(-1) and an excellent rate capability with capacitance retention of 50.5% at 30 A g^(-1). For the asymmetric device fabricated using Ni(OH)_2//VN/C membranes, a high energy density of 43.0 Wh kg^(-1) at a power density of800 W kg^(-1) was observed. Moreover, the device also showed good cycling stability of 82.9% at a current density of 1.0 A g^(-1) after 8000 cycles. This work may throw a light on simply the fabrication of other high-performance transition-metal nitridebased supercapacitor or other energy storage devices.展开更多
The development of wearable multifunctional electromagnetic protective fabrics with multifunctional,low cost,and high efficiency remains a challenge.Here,inspired by the unique flower branch shape of“Thunberg’s mead...The development of wearable multifunctional electromagnetic protective fabrics with multifunctional,low cost,and high efficiency remains a challenge.Here,inspired by the unique flower branch shape of“Thunberg’s meadowsweet”in nature,a nanofibrous composite membrane with hierarchical structure was constructed.Integrating sophisticated 0D@2D@1D hierarchical structures with multiple heterointerfaces can fully unleash the multifunctional application potential of composite membrane.The targeted induction method was used to precisely regulate the formation site and morphology of the metal–organic framework precursor,and intelligently integrate multiple heterostructures to enhance dielectric polarization,which improves the impedance matching and loss mechanisms of the electromagnetic wave absorbing materials.Due to the synergistic enhancement of electrospinning-derived carbon nanofiber“stems”,MOF-derived carbon nanosheet“petals”and transition metal selenide nano-particle“stamens”,the CoxSey/NiSe@CNSs@CNFs(CNCC)composite membrane obtains a minimum reflection loss value(RL_(min))of-68.40 dB at 2.6 mm and a maximum effective absorption bandwidth(EAB)of 8.88 GHz at a thin thickness of 2.0 mm with a filling amount of only 5 wt%.In addition,the multi-component and hierarchical heterostructure endow the fibrous membrane with excellent flexibility,water resistance,thermal management,and other multifunctional properties.This work provides unique perspectives for the precise design and rational application of multifunctional fabrics.展开更多
Based on the general [Mo] equivalent criterion and d-electron orbital theory, a new ultrahigh-strength βtitanium alloy with eight major elements(Ti-4.5Al-6.5Mo-2Cr-2.6Nb-2Zr-2Sn-1V, TB17) for industrial applications ...Based on the general [Mo] equivalent criterion and d-electron orbital theory, a new ultrahigh-strength βtitanium alloy with eight major elements(Ti-4.5Al-6.5Mo-2Cr-2.6Nb-2Zr-2Sn-1V, TB17) for industrial applications was developed. An ingot of five tons was successfully melted by thrice vacuum consumable arc melting. The microstructure and elements partitioning of different conditions were investigated systematically. The results suggest that the hierarchical structures of micro-scale first α phase(αf), nano-scale secondary α phase(αs), and ultrafine FCC substructures can be tailored by solution plus aging(STA) heat treatment. The lateral and epitaxial growth of αfphase promotes the HCP-α to FCC substructure transformation with the help of elements partitioning during the aging process. Moreover, the element V, generally regarded as β stabilizer, is found to mainly concentrate in the Al-rich αfphase in this study probably due to its relatively lower content and the strong bonding energy of Al-V. The hierarchical structure has a strong interaction with dislocations, which contributes to achieve a superhigh strength of 1376 MPa.In addition, the plastic strain is partitioned in the multi-scale precipitates(such as the α and FCC substructures) and β matrix, resulting in a considerable plasticity. TEM observation demonstrates that high density entangled dislocations at interfaces and mechanical twins exist in the STA sample after tensile test. It can be deduced that both dislocation slipping and twinning mechanisms are present in this alloy.Therefore, TB17 alloy can serve as an excellent candidate for structural materials on aircrafts that require high strength and lightweight.展开更多
With the continuous expansion of digital infrastructures,malicious behaviors in host systems have become increasingly sophisticated,often spanning multiple processes and employing obfuscation techniques to evade detec...With the continuous expansion of digital infrastructures,malicious behaviors in host systems have become increasingly sophisticated,often spanning multiple processes and employing obfuscation techniques to evade detection.Audit logs,such as Sysmon,offer valuable insights;however,existing approaches typically flatten event sequences or rely on generic graph models,thereby discarding the natural parent-child process hierarchy that is critical for analyzing multiprocess attacks.This paper proposes a structure-aware threat detection framework that transforms audit logs into a unified two-dimensional(2D)spatio-temporal representation,where process hierarchy is modeled as the spatial axis and event chronology as the temporal axis.In addition,entropy-based features are incorporated to robustly capture obfuscated and non-linguistic strings,overcoming the limitations of semantic embeddings.The model’s performance was evaluated on publicly available datasets,achieving competitive results with an accuracy exceeding 95%and an F1-score of at least 0.94.The proposed approach provides a promising and reproducible solution for detecting attacks with unknown indicators of compromise(IoCs)by analyzing the relationships and behaviors of processes recorded in large-scale audit logs.展开更多
In the present research, hierarchical structure observation and mechanical property characterization for a type of biomaterial are carried out. The investigated bioma- terial is Hyriopsis cumingii, a typical limnetic ...In the present research, hierarchical structure observation and mechanical property characterization for a type of biomaterial are carried out. The investigated bioma- terial is Hyriopsis cumingii, a typical limnetic shell, which consists of two different structural layers, a prismatic ＂pillar＂ structure and a nacreous ＂brick and mortar＂ structure. The prismatic layer looks like a ＂pillar forest＂ with variationsection pillars sized on the order of several tens of microns. The nacreous material looks like a ＂brick wall＂ with bricks sized on the order of several microns. Both pillars and bricks are composed of nanoparticles. The mechanical properties of the hierarchical biomaterial are measured by using the nanoindentation test. Hardness and modulus are measured for both the nacre layer and the prismatic layer, respectively. The nanoindentation size effects for the hierarchical structural materials are investigated experimentally. The results show that the prismatic nanostructured material has a higher stiffness and hardness than the nacre nanostructured material. In addition, the nanoindentation size effects for the hierarchical structural materials are described theoretically, by using the trans-scale mechanics theory considering both strain gradient effect and the surface/interface effect. The modeling results are consistent with experimental ones.展开更多
A focus of the current nanotechnology has shifted from routine fabrication of nanostructures to designing functional electronic devices and realizing their immense potentials for applications. Due to infusion of multi...A focus of the current nanotechnology has shifted from routine fabrication of nanostructures to designing functional electronic devices and realizing their immense potentials for applications. Due to infusion of multi-functionality into a single system, the utilization of hetero-, core/shell and hierarchical nanostructures has become the key issue for building such devices. ZnS, due to its direct wide bandgap, high index of refraction, high transparency in the visible range and intrinsic polarity, is one of the most useful semiconductors for a wide range of electronics applications. This article provides a dense review of the state-of-the-art research activities in one-dimensional （1D） ZnS-based hetero-, core/shell and hierarchical nanostructures. The particular emphasis is put on their syntheses and applications.展开更多
Supercapacitors with unique performance have been widely utilized in many fields. Herein, we report a nitrogen and sulfur co-doped graphene aerogel(N/S-GA-2) prepared using a low toxic precursor for high-performance s...Supercapacitors with unique performance have been widely utilized in many fields. Herein, we report a nitrogen and sulfur co-doped graphene aerogel(N/S-GA-2) prepared using a low toxic precursor for high-performance supercapacitors. The as-obtained material possesses a hierarchically porous structure and a large number of electrochemical active sites. At a current density of 1 Ag^-1, the specific capacitance of the N/S-GA-2 for supercapacitors with the ionic liquid as the electrolyte is 169.4 Fg^-1, and the corresponding energy density is 84.5 Wh kg^-1.At a power density of 8.9 k W kg^-1, the energy density can reach up to 75.7 Wh kg^-1, showing that the N/S-GA-2 has an excellent electrochemical performance. Consequently, the N/S-GA-2 can be used as a promising candidate of electrode materials for supercapacitors with high power density and high energy density.展开更多
Potassium-ion batteries(KIBs)are a potential candidate to lithium-ion batteries(LIBs)but possess unsatisfactory capacity and rate properties.Herein,the metallic cobalt selenide quantum dots(Co0.85Se-QDs)encapsulated i...Potassium-ion batteries(KIBs)are a potential candidate to lithium-ion batteries(LIBs)but possess unsatisfactory capacity and rate properties.Herein,the metallic cobalt selenide quantum dots(Co0.85Se-QDs)encapsulated in mesoporous carbon matrix were designed via a direct hydrothermal method.Specifically,the cobalt selenide/carbon composite(Co0.85Se-QDs/C)possesses tertiary hierarchical structure,which is the primary quantum dots,the secondary petals flake,and the tertiary hollow micropolyhedron framework.Co0.85Se-QDs are homogenously embedded into the carbon petals flake,which constitute the hollow polyhedral framework.This unique structure can take the advantages of both nanoscale and microscale features:Co0.85Se-QDs can expand in a multidimensional and ductile carbon matrix and reduce the K-intercalation stress in particle dimensions;the micropetals can restrain the agglomeration of active materials and promote the transportation of potassium ion and electron.In addition,the hollow carbon framework buffers volume expansion,maintains the structural integrity,and increases the electronic conductivity.Benefiting from this tertiary hierarchical structure,outstanding K-storage performance(402 mAh g?1 after 100 cycles at 50 mA g?1)is obtained when Co0.85Se-QDs/C is used as KIBs anode.More importantly,the selenization process in this work is newly reported and can be generally extended to prepare other quantum dots encapsulated in edge-limited frameworks for excellent energy storage.展开更多
A novel synthesis of hierarchical porous carbons （HPCs）with 3D open-cell structure based on nanosilica- embedded emulsion-templated polymerization was reported. An oil-in-water emulsion containing SiO2 colloids was ...A novel synthesis of hierarchical porous carbons （HPCs）with 3D open-cell structure based on nanosilica- embedded emulsion-templated polymerization was reported. An oil-in-water emulsion containing SiO2 colloids was fabricated using liquid paraffin as an oil phase, resorcinol/formaldehyde and silica sol as an aqueous phase, and Span 80/Tween 80 as emulsifiers. HPCs with macropore cores, open meso/ macropore windows, and abundant micropores were synthesized by the polymerization and carbonization of the emulsion, followed by scaffold removal and further KOH activation. A typical HPCs sample as supercapacitor electrode shows the charge/discharge capability under large loading current density （30 A/g） coupling with a reasonable electrochemical capacitance in KOH electrolyte solution.展开更多
Rational regulation on pore structure and active site density plays critical roles in enhancing the performance of Fe-N-C catalysts. As the microporous structure of the carbon substrate is generally regarded as the ac...Rational regulation on pore structure and active site density plays critical roles in enhancing the performance of Fe-N-C catalysts. As the microporous structure of the carbon substrate is generally regarded as the active site hosts, its hostility to electron/mass transfer could lead to the incomplete fulfillment of the catalytic activity. Besides, the formation of inactive metallic Fe particles during the conventional catalyst synthesis could also decrease the active site density and complicate the identification of real active site. Herein, we developed a facial hydrogen etching methodology to yield single site Fe-N-C catalysts featured with micro/mesoporous hierarchical structure. The hydrogen concentration in pyrolysis process was designated to effectively regulate the pore structure and active site density of the resulted catalysts.The optimized sample achieves excellent ORR catalytic performance with an ultralow H2O2 yield(1%)and superb stability over 10,000 cycles. Our finding provides new thoughts for the rational design of hierarchically porous carbon-based materials and highly promising non-precious metal ORR catalysts.展开更多
This study explored a multi-mechanism approach to improving the mechanical properties of a Co CrFe Mn Ni high-entropy alloy through non-equiatomic alloy design and processing.The alloy design ensures a single-phase fa...This study explored a multi-mechanism approach to improving the mechanical properties of a Co CrFe Mn Ni high-entropy alloy through non-equiatomic alloy design and processing.The alloy design ensures a single-phase face-centered cubic structure while lowering the stacking fault energy to encourage the formation of deformation twins and stacking faults by altering the equiatomic composition of the alloy.The processing strategy applied helped create a hierarchical grain size gradient microstructure with a high nanotwins population.This was achieved by means of rotationally accelerated shot peening(RASP).The non-equiatomic Co Cr Fe Mn Ni high-entropy alloy achieved a yield strength of 750 MPa,a tensile strength of 1050 MPa,and tensile uniform elongation of 27.5%.The toughness of the alloy was 2.53×10^(10)k J/m^(3),which is about 2 times that of the same alloy without the RASP treatment.The strength increase is attributed to the effects of grain boundary strengthening,dislocation strengthening,twin strengthening,and hetero-deformation strengthening associated with the heterogeneous microstructure of the alloy.The concurrent occurrence of the multiple deformation mechanisms,i.e.,dislocation deformation,twining deformation and microband deformation,contributes to achieving a suitable strain hardening of the alloy that helps to prevent early necking and to assure steady plastic deformation for high toughness.展开更多
基金supported by the Natural Science Foundation of Shandong Province(No.ZR2022MB034)the Development Program Project of the Young Innovation Team of Institutions of Higher Learning in Shandong Province。
文摘Endowing stimuli-responsive materials with micro-nano structures is an intriguing strategy for the fabrication of superwetting surfaces;however,its application is limited by poor chemical/mechanical stability.Herein,a simple and versatile strategy was developed to fabricate durable polymeric superwetting surfaces with photoswitchable wettability on hierarchically structured metallic substrates.Inspired by nature,a novel functional terpolymer incorporating mussel-inspired catechol groups,photoresponsive azobenzene groups,and low-surface-energy fluorine-containing groups was synthesized via solution radical polymerization.The azobenzene-containing terpolymer possesses outstanding photoresponsiveness in both the solution and film states because of the trans-cis isomerization of the azobenzene moieties.After dip-coating with the mussel-inspired azo-copolymer,the as-prepared smart surfaces exhibited a photo-triggered change in wettability between high hydrophobicity and superhydrophilicity.More importantly,these superwetting surfaces with enhanced adhesion properties can tolerate harsh environmental conditions and repeated abrasion tests,thereby demonstrating excellent chemical robustness and mechanical durability.This study paves a new avenue for the convenient and large-scale fabrication of robust smart surfaces that could find widespread potential applications in microfluidic devices,water treatment,and functional coatings.
基金financially supported by the National Natural Science Foundation of China(Nos.52275290 and 51905222)the Research Project of the State Key Laboratory of Mechanical System and Oscillation(No.MSV202419)+2 种基金Major Program of the National Natural Science Foundation of China for Basic Theory and Key Technology of Tri-Co Robots(No.92248301)Opening Project of the Key Laboratory of Bionic Engineering(Ministry of Education),Jilin University(No.KF2023006)Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.SJCX23_2091)。
文摘This work proposes a bioinspired hierarchical actuation strategy based on liquid crystal elastomers(LCEs),inspired by the helical topological dynamic adaptation mechanism of plant tendrils,to overcome the bottleneck of precise anisotropic control in LCEs.Mechanically pre-programmed hierarchical LCE structures responsive to near-infrared(NIR)light were fabricated:the oriented constrained actuator achieves asymmetric contraction under NIR irradiation,enabling reversible switching between helix and planar morphologies with multi-terrain grasping capability;the biomimetic vine-like helical actuator,composed of Ag nanowire photothermal layers combined with helical LCE,utilizes temperaturegradient-induced phase transition wave propagation to achieve NIR-controlled climbing motion;the M?bius topology actuator realizes reversible deformation or self-locking states by tuning the twist angle(180°/360°);based on these,a bioinspired koala-like concentric soft robot was constructed,successfully demonstrating tree trunk climbing.This study reveals that artificial helical stretching significantly enhances the molecular chain orientation of LCEs(surpassing uniaxial stretching),reaching up to 1000%pre-strain,and the Ag NWs/LCE/PI(Polyimide)tri-layer structure achieves efficient photothermal-mechanical energy conversion via localized surface plasmon resonance(LSPR).This study provides a new paradigm for soft robotics material design and topological programming,demonstrating the potential for remote operation and adaptive grasping.
基金supported by the National Natural Science Foundation of China(Grant No.52405414)the China Postdoctoral Science Foundation(Grant No.2024M762580)+1 种基金Young Talent Fund of Xi'an Association for Science and Technology(Grant No.0959202513033)the Youth Innovation Team of Shaanxi Universities,and the Fundamental Research Funds for Central Universities.The authors gratefully acknowledge the support by the Instrumental Analysis Center of Xi’an Jiaotong University for sample characterization.
文摘In the background of carbon neutrality,monolithic ceramic catalysts are universally used in energy conversion and chemical catalysis due to the high heat and mass transfer efficiencies,low bed pressures,and scalability through modular design.However,traditional manufacturing processes are limited by mold dependence,organic solvent toxicity,and insufficient molding capability for complex structures,resulting in difficulty achieving precise regulation of cross-scale pores.Additive manufacturing(AM)technology employs a digital layered molding strategy to achieve the cross-scale structural regulation of catalysts from macroscopic flow channels to mesopores and micropores.This paper summarizes recent advances in the structural design of monolithic catalysts enabled by AM technologies and highlights their emerging applications in catalytic processes.Structurally,AM-fabricated monoliths have been effectively employed in key chemical reactions such as fuel reforming,CO_(2)conversion,biofuel synthesis.Strategies such as geometrical topology optimization,multi-scale pore synergy,biomimetic structural design,and functional gradient integration have been utilized to enhance heat and mass transport,reduce pressure drops,and improve overall catalytic performance.By overcoming the limitations of traditional catalysts,AM technologies create a new paradigm for addressing the longstanding challenge of coupling mass transfer with reaction kinetics.This approach provides a feasible pathway for driving both theoretical innovation and practical implementation of high-efficiency catalytic systems.
基金supported by the National Natural Science Foundation of China(Nos.22271178,22301239)Science and Technology New Star in Shaanxi Province(No.2023KJXX-045)+3 种基金the Youth Talent Promotion Project of Science and Technology Association of Universities of Shaanxi Province(No.20240601)Shaanxi Provincial Department of Education service local special project,industrialization cultivation project(No.23JC007)the Research Program of the Shaanxi Provincial Department of Education(Nos.23JK0596,23JP135)the Open Foundation of Xi’an Key Laboratory of Functional Supramolecular Structure and Materials(No.CFZKFKT23003).
文摘The regulation of the interfacial electric field plays a pivotal role in magnifying the electromagnetic en-ergy attenuation capability during the design and synthesis of efficient and tunable absorbers for elec-tromagnetic waves(EMW).Herein,a rational and universally applicable two-step hydrothermal method strategy was proposed to effectively control the electronic structure of Mott-Schottky EMW absorbing materials derived from Co-MOF.The as-synthesized Co_(3)S_(4)@MoS_(2)/NC ensures efficient electron transfer,while the change redistribution leads to the emergence of additional electric dipoles under an external EMM field.In addition,the hierarchical Co_(3)S_(4)@MoS_(2)/NC nano-architecture with a hierarchical arrange-ment in 2D and 3D offers more polarization sites,thereby extending the path for EMW transmission through multiple reflections and scattering.The potential to enhance the EMW absorption performance of Co_(3)S_(4)@MoS_(2)/NC lies in its unique microstructure and substantial surface area,which optimize impedance matching properties through a synergistic effect of dipole and interfacial polarization induced by Mott-Schottky heterointerfaces.As anticipated,the Co_(3)S_(4)@MoS_(2)/NC exhibits a maximum EMW absorption ca-pacity with an RLmin value of-41.97 dB and a broad EAB of 4.24 GHz at a thickness of 2.0 mm.This study provides insights for designing highly efficient Mott-Schottky EMW absorbing materials at the molecular level rationally.
基金supported by the National Key Research and Development Program of China(No.2019YFA0110600)the Science and Technology Support Program of Sichuan Province(No.2019YJ0161).
文摘Hierarchical porous structure,which include macropores,minor pores,and micropores in scaffolds,are essential in the multiple biological functions of bone repair and regeneration.In this study,patientcustomized calcium-deficient hydroxyapatite(CDHA)scaffolds with three-level hierarchical porous structure were fabricated by indirect 3D printing technology and particulate leaching method.The sacrificial template scaffolds were fabricated using a photo-curing 3D printer,which provided a prerequisite for the integral structure and interconnected macropores of CDHA scaffolds.Additionally,20 wt%pore former was incorporated into the slurry to enhance the content of smaller pores within the CDHA-2 scaffolds,and then the CDHA-2 scaffolds were sintered to remove the sacrificial template scaffolds and pore former.The obtained CDHA-2 scaffolds exhibited interconnected macropores(300-400μm),minor pores(∼10-100μm),and micropores(<10μm)distributed throughout the scaffolds,which could promote bone tissue ingrowth,increase surface roughness,and enhance protein adsorption of scaffolds.In vitro studies identified that CDHA-2 scaffolds had nanocrystal grains,high specific surface area,and outstanding protein adsorption capacity,which could provide a microenvironment for cell adhesion,spreading,and proliferation.In addition,the murine intramuscular implantation experiment suggested that CDHA-2 scaffolds exhibited excellent osteoinductivity and were superior to traditional BCP ceramics under conditions without the addition of live cells and exogenous growth factors.The rabbit calvarial defect repair results indicated that CDHA-2 scaffolds could enhance in situ bone regeneration.In conclusion,these findings demonstrated that the hierarchical porous structure of CDHA scaffolds was a pivotal factor in modulating osteoinductivity and bone regeneration,and CDHA-2 scaffolds were potential candidates for bone regeneration.
基金National Natural Science Foundation of China,Grant/Award Number:52003248Henan Province Youth Health Science and Technology Innovation Talent Training Program,Grant/Award Number:YQRC2023007+1 种基金Henan Province Excellent Youth Science Fund,Grant/Award Number:242300421064Joint Fund Predominant Discipline Cultivation Project of Henan Province,Grant/Award Number:232301420036.
文摘Switchable radiative cooling/heating holds great promise for mitigating the global energy and environmental crisis.Here,we reported a cost-effective,high-strength Janus film through surface optical engineering waste paper with one side decorated by a hydrophobic polymeric cooling coating consisting of micro/nanopore/particle hierarchical structure and the other side coated with hydrophilic MXene nanosheets for heating.The cooling surface demonstrates high solar reflectivity(96.3%)and infrared emissivity(95.5%),resulting in daytime/nighttime sub-ambient radiative cooling of 6℃/8℃with the theoretical cooling power of 100.6 and 138.5Wm^(−2),respectively.The heating surface exhibits high solar absorptivity(83.7%)and low infrared emissivity(15.2%),resulting in excellent radiative heating capacity for vehicle charging pile(~6.2℃)and solar heating performance.Impressively,the mechanical strength of Janus film increased greatly by 563%compared with that of pristine waste paper,which is helpful for its practical applications in various scenarios for switchable radiative thermal management through mechanical flipping.Energy-saving simulation results reveal that significant total energy savings of up to 32.4MJm^(−2) can be achieved annually(corresponding to the 12.4%saving ratio),showing the immense importance of reducing carbon footprint and promoting carbon neutrality.
基金Supported by National Natural Science Foundation of China(Grant Nos.52035004,52105434).
文摘Hierarchical micro/nanograting structures have attracted increasing attention owing to their significant applications in the fields of structural coloring,anti-counterfeiting,and decoration.Thus,the fabrication of hierarchical micro/nanograting structures is important for these applications.In this study,a strategy for machining hierarchical micro/nanograting structures is developed by controlling the tool movement trajectory.A coupling Euler-Lagrange finite element model is established to simulate the machining process.The effect of the machining methods on the nanograting formation is demonstrated,and a suitable machining method for reducing the cutting force is obtained.The height of the nanograting decreases with an increase in the tool edge radius.Furthermore,optical variable devices(OVDs)are machined using an array overlap machining approach.Coding schemes for the parallel column unit crossover and column unit in the groove crossover are designed to achieve high-quality machining of OVDs.The coloring of the logo of the Harbin Institute of Technology and the logo of the centennial anniversary of the Harbin Institute of Technology on the surface of metal samples,such as aluminum alloys,is realized.The findings of this study provide a method for the fabrication of hierarchical micro/nanograting structures that can be used to prepare OVDs.
基金supported by the National Natural Science Foundation of China (51320105001, 51372190, 21573170, 51272199, 21433007)the National Basic Research Program of China (973 program, 2013CB632402)+2 种基金the Natural Science Foundation of Hubei Province (2015CFA001)the Fundamental Research Funds for the Central Universities (WUT: 2015-Ⅲ-034)Innovative Research Funds of SKLWUT (2015-ZD-1)~~
文摘Flower-like tin oxide-supported platinum（Pt/SnOx） with a hierarchical structure was synthesized by a hydrothermal method and characterized by XRD,SEM,TEM,high resolution TEM,XPS and nitrogen adsorption.The flower-like Pt/SnOx microspheres of 1 μm in diameter were composed of staggered petal-like nanosheets with a thickness of 20 nm.Pt nanoparticles（NPs） of 2-3 nm were well dispersed on the SnOx nanosheets.The catalyst was tested in the catalytic oxidation of gaseous formaldehyde（HCHO） at room temperature,and exhibited enhanced activity compared to Pt NPs supported on commercial SnO and ground SnOx.HCHO removal of 87%was achieved over the hierarchical Pt/SnOx after 1 h of reaction,which was 1.5 times that over the ground SnOx-supported Pt（Pt/g-SnOx）,and the high activity was maintained after six recycles,showing the high stability of this catalyst.HCHO decomposition kinetics was modeled as a second order reaction.The reaction rate constant for Pt/SnOx was 5.6 times higher than Pt/g-SnOx.The hierarchical pore structure was beneficial for the diffusion and adsorption of HCHO molecules,and the highly dispersed Pt NPs on the SnOx nanosheets were the active sites for the oxidative decomposition of HCHO into CO2 and H2O.This study provided a promising approach for designing efficient catalysts for indoor HCHO removal at ambient temperature.
基金supported by the National Natural Science Foundation of China (51203071,51363014,51463012,and 51763014)China Postdoctoral Science Foundation (2014M552509 and 2015T81064)+2 种基金Natural Science Funds of the Gansu Province (1506RJZA098)the Program for Hongliu Distinguished Young Scholars in Lanzhou University of Technology (J201402)Joint fund between Shenyang National Laboratory for Materials Science and State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals (18LHPY002)
文摘Transition-metal nitrides exhibit wide potential windows and good electrochemical performance, but usually experience imbalanced practical applications in the energy storage field due to aggregation, poor circulation stability, and complicated syntheses. In this study, a novel and simple multiphase polymeric strategy was developed to fabricate hybrid vanadium nitride/carbon(VN/C) membranes for supercapacitor negative electrodes, in which VN nanoparticles were uniformly distributed in the hierarchical porous carbon 3D networks. The supercapacitor negative electrode based on VN/C membranes exhibited a high specific capacitance of 392.0 F g^(-1) at 0.5 A g^(-1) and an excellent rate capability with capacitance retention of 50.5% at 30 A g^(-1). For the asymmetric device fabricated using Ni(OH)_2//VN/C membranes, a high energy density of 43.0 Wh kg^(-1) at a power density of800 W kg^(-1) was observed. Moreover, the device also showed good cycling stability of 82.9% at a current density of 1.0 A g^(-1) after 8000 cycles. This work may throw a light on simply the fabrication of other high-performance transition-metal nitridebased supercapacitor or other energy storage devices.
基金supported by the National Natural Science Foundation of China(No.51407134,No.52002196)Natural Science Foundation of Shandong Province(No.ZR2019YQ24,No.ZR2020QF084)+2 种基金Taishan Scholars and Young Experts Program of Shandong Province(No.tsqn202103057)the Qingchuang Talents Induction Program of Shandong Higher Education Institution(Research and Innovation Team of Structural-Functional Polymer Composites)Special Financial of Shandong Province(Structural Design of Highefficiency Electromagnetic Wave-absorbing Composite Materials and Construction of Shandong Provincial Talent Teams(No.37000022P990304116449)).
文摘The development of wearable multifunctional electromagnetic protective fabrics with multifunctional,low cost,and high efficiency remains a challenge.Here,inspired by the unique flower branch shape of“Thunberg’s meadowsweet”in nature,a nanofibrous composite membrane with hierarchical structure was constructed.Integrating sophisticated 0D@2D@1D hierarchical structures with multiple heterointerfaces can fully unleash the multifunctional application potential of composite membrane.The targeted induction method was used to precisely regulate the formation site and morphology of the metal–organic framework precursor,and intelligently integrate multiple heterostructures to enhance dielectric polarization,which improves the impedance matching and loss mechanisms of the electromagnetic wave absorbing materials.Due to the synergistic enhancement of electrospinning-derived carbon nanofiber“stems”,MOF-derived carbon nanosheet“petals”and transition metal selenide nano-particle“stamens”,the CoxSey/NiSe@CNSs@CNFs(CNCC)composite membrane obtains a minimum reflection loss value(RL_(min))of-68.40 dB at 2.6 mm and a maximum effective absorption bandwidth(EAB)of 8.88 GHz at a thin thickness of 2.0 mm with a filling amount of only 5 wt%.In addition,the multi-component and hierarchical heterostructure endow the fibrous membrane with excellent flexibility,water resistance,thermal management,and other multifunctional properties.This work provides unique perspectives for the precise design and rational application of multifunctional fabrics.
基金financial support from “13th five-year plan” equipment pre-research project of China (41422010501)。
文摘Based on the general [Mo] equivalent criterion and d-electron orbital theory, a new ultrahigh-strength βtitanium alloy with eight major elements(Ti-4.5Al-6.5Mo-2Cr-2.6Nb-2Zr-2Sn-1V, TB17) for industrial applications was developed. An ingot of five tons was successfully melted by thrice vacuum consumable arc melting. The microstructure and elements partitioning of different conditions were investigated systematically. The results suggest that the hierarchical structures of micro-scale first α phase(αf), nano-scale secondary α phase(αs), and ultrafine FCC substructures can be tailored by solution plus aging(STA) heat treatment. The lateral and epitaxial growth of αfphase promotes the HCP-α to FCC substructure transformation with the help of elements partitioning during the aging process. Moreover, the element V, generally regarded as β stabilizer, is found to mainly concentrate in the Al-rich αfphase in this study probably due to its relatively lower content and the strong bonding energy of Al-V. The hierarchical structure has a strong interaction with dislocations, which contributes to achieve a superhigh strength of 1376 MPa.In addition, the plastic strain is partitioned in the multi-scale precipitates(such as the α and FCC substructures) and β matrix, resulting in a considerable plasticity. TEM observation demonstrates that high density entangled dislocations at interfaces and mechanical twins exist in the STA sample after tensile test. It can be deduced that both dislocation slipping and twinning mechanisms are present in this alloy.Therefore, TB17 alloy can serve as an excellent candidate for structural materials on aircrafts that require high strength and lightweight.
基金supported by the Nuclear Safety Research Program through Korea Foundation of Nuclear Safety(KoFONS)using the financial resource granted by the Nuclear Safety and Security Commission(NSSC)of the Republic of Korea(Grant number:2106061,50%)supported by the Institute of Information&Communications Technology Planning&Evaluation(IITP)grant funded by the Korea government(MSIT)(RS-2025-25394739,Development of Security Enhancement Technology for Industrial Control Systems Based on S/HBOM Supply Chain Protection,50%).
文摘With the continuous expansion of digital infrastructures,malicious behaviors in host systems have become increasingly sophisticated,often spanning multiple processes and employing obfuscation techniques to evade detection.Audit logs,such as Sysmon,offer valuable insights;however,existing approaches typically flatten event sequences or rely on generic graph models,thereby discarding the natural parent-child process hierarchy that is critical for analyzing multiprocess attacks.This paper proposes a structure-aware threat detection framework that transforms audit logs into a unified two-dimensional(2D)spatio-temporal representation,where process hierarchy is modeled as the spatial axis and event chronology as the temporal axis.In addition,entropy-based features are incorporated to robustly capture obfuscated and non-linguistic strings,overcoming the limitations of semantic embeddings.The model’s performance was evaluated on publicly available datasets,achieving competitive results with an accuracy exceeding 95%and an F1-score of at least 0.94.The proposed approach provides a promising and reproducible solution for detecting attacks with unknown indicators of compromise(IoCs)by analyzing the relationships and behaviors of processes recorded in large-scale audit logs.
基金The research was supported by the National Basic Research Program of China (Grant 2012CB937500),the National Natural Science Foundation of China (Grants 91216108,11432014),and the CAS/SAFEA International Partnership Program for Creative Reserch Teams
文摘In the present research, hierarchical structure observation and mechanical property characterization for a type of biomaterial are carried out. The investigated bioma- terial is Hyriopsis cumingii, a typical limnetic shell, which consists of two different structural layers, a prismatic ＂pillar＂ structure and a nacreous ＂brick and mortar＂ structure. The prismatic layer looks like a ＂pillar forest＂ with variationsection pillars sized on the order of several tens of microns. The nacreous material looks like a ＂brick wall＂ with bricks sized on the order of several microns. Both pillars and bricks are composed of nanoparticles. The mechanical properties of the hierarchical biomaterial are measured by using the nanoindentation test. Hardness and modulus are measured for both the nacre layer and the prismatic layer, respectively. The nanoindentation size effects for the hierarchical structural materials are investigated experimentally. The results show that the prismatic nanostructured material has a higher stiffness and hardness than the nacre nanostructured material. In addition, the nanoindentation size effects for the hierarchical structural materials are described theoretically, by using the trans-scale mechanics theory considering both strain gradient effect and the surface/interface effect. The modeling results are consistent with experimental ones.
基金World Premier International Research Center Initiative(WPI Initiative)on Materials Nanoarchitronics,MEXT,Japanthe Japan Society for the Promotion of Science (JSPS)for a support in the form of a fellowship tenable at the National Institute for Materials Science,Tsukuba,Japan.
文摘A focus of the current nanotechnology has shifted from routine fabrication of nanostructures to designing functional electronic devices and realizing their immense potentials for applications. Due to infusion of multi-functionality into a single system, the utilization of hetero-, core/shell and hierarchical nanostructures has become the key issue for building such devices. ZnS, due to its direct wide bandgap, high index of refraction, high transparency in the visible range and intrinsic polarity, is one of the most useful semiconductors for a wide range of electronics applications. This article provides a dense review of the state-of-the-art research activities in one-dimensional （1D） ZnS-based hetero-, core/shell and hierarchical nanostructures. The particular emphasis is put on their syntheses and applications.
基金Financial support from the National Natural Science Foundation of China (Nos. 21873026 and 21573058)the Program for Innovative Research Team in Science and Technology in University of Henan Province (17IRTSTHN 001) is gratefully acknowledged
文摘Supercapacitors with unique performance have been widely utilized in many fields. Herein, we report a nitrogen and sulfur co-doped graphene aerogel(N/S-GA-2) prepared using a low toxic precursor for high-performance supercapacitors. The as-obtained material possesses a hierarchically porous structure and a large number of electrochemical active sites. At a current density of 1 Ag^-1, the specific capacitance of the N/S-GA-2 for supercapacitors with the ionic liquid as the electrolyte is 169.4 Fg^-1, and the corresponding energy density is 84.5 Wh kg^-1.At a power density of 8.9 k W kg^-1, the energy density can reach up to 75.7 Wh kg^-1, showing that the N/S-GA-2 has an excellent electrochemical performance. Consequently, the N/S-GA-2 can be used as a promising candidate of electrode materials for supercapacitors with high power density and high energy density.
基金financially supported by Beijing Natural Science Foundation(No.2192034)China Postdoctoral Science Foundation(No.2018M631335)National Key R&D Program of China(No.2018YFB0905600).
文摘Potassium-ion batteries(KIBs)are a potential candidate to lithium-ion batteries(LIBs)but possess unsatisfactory capacity and rate properties.Herein,the metallic cobalt selenide quantum dots(Co0.85Se-QDs)encapsulated in mesoporous carbon matrix were designed via a direct hydrothermal method.Specifically,the cobalt selenide/carbon composite(Co0.85Se-QDs/C)possesses tertiary hierarchical structure,which is the primary quantum dots,the secondary petals flake,and the tertiary hollow micropolyhedron framework.Co0.85Se-QDs are homogenously embedded into the carbon petals flake,which constitute the hollow polyhedral framework.This unique structure can take the advantages of both nanoscale and microscale features:Co0.85Se-QDs can expand in a multidimensional and ductile carbon matrix and reduce the K-intercalation stress in particle dimensions;the micropetals can restrain the agglomeration of active materials and promote the transportation of potassium ion and electron.In addition,the hollow carbon framework buffers volume expansion,maintains the structural integrity,and increases the electronic conductivity.Benefiting from this tertiary hierarchical structure,outstanding K-storage performance(402 mAh g?1 after 100 cycles at 50 mA g?1)is obtained when Co0.85Se-QDs/C is used as KIBs anode.More importantly,the selenization process in this work is newly reported and can be generally extended to prepare other quantum dots encapsulated in edge-limited frameworks for excellent energy storage.
基金supported by the National Natural Science Foundation of China(Nos.21207099 and 21273162)Science and Technology Commission of Shanghai Municipality,China(Nos. 11nm0501000 and 12ZR1451100)Key Subject of Shanghai Municipal Education Commission(No.J50102)
文摘A novel synthesis of hierarchical porous carbons （HPCs）with 3D open-cell structure based on nanosilica- embedded emulsion-templated polymerization was reported. An oil-in-water emulsion containing SiO2 colloids was fabricated using liquid paraffin as an oil phase, resorcinol/formaldehyde and silica sol as an aqueous phase, and Span 80/Tween 80 as emulsifiers. HPCs with macropore cores, open meso/ macropore windows, and abundant micropores were synthesized by the polymerization and carbonization of the emulsion, followed by scaffold removal and further KOH activation. A typical HPCs sample as supercapacitor electrode shows the charge/discharge capability under large loading current density （30 A/g） coupling with a reasonable electrochemical capacitance in KOH electrolyte solution.
基金supported by the National Natural Science Foundation of China(21633008,21433003,U1601211,21733004)National Science and Technology Major Project(2016YFB0101202)+1 种基金Jilin Province Science and Technology Development Program(20150101066JC,20160622037JC,20170203003SF,20170520150JH)Hundred Talents Program of Chinese Academy of Sciences and the Recruitment Program of Foreign Experts(WQ20122200077)
文摘Rational regulation on pore structure and active site density plays critical roles in enhancing the performance of Fe-N-C catalysts. As the microporous structure of the carbon substrate is generally regarded as the active site hosts, its hostility to electron/mass transfer could lead to the incomplete fulfillment of the catalytic activity. Besides, the formation of inactive metallic Fe particles during the conventional catalyst synthesis could also decrease the active site density and complicate the identification of real active site. Herein, we developed a facial hydrogen etching methodology to yield single site Fe-N-C catalysts featured with micro/mesoporous hierarchical structure. The hydrogen concentration in pyrolysis process was designated to effectively regulate the pore structure and active site density of the resulted catalysts.The optimized sample achieves excellent ORR catalytic performance with an ultralow H2O2 yield(1%)and superb stability over 10,000 cycles. Our finding provides new thoughts for the rational design of hierarchically porous carbon-based materials and highly promising non-precious metal ORR catalysts.
基金the support of Basic Science Center Program for Multiphase Evolution in Hyper-gravity of the National Natural Science Foundation of China(51988101)NSFC programs(52071003,91860202,11604006)+4 种基金Beijing Municipal Education Commission Project(PXM2020014204000021 and PXM2019014204500032)Beijing Outstanding Young Scientists Projects(BJJWZYJH01201910005018)Beijing Natural Science Foundation(Z180014)“111”project(DB18015)the support by the Australian Research Council(DP190102990)to his work in this study。
文摘This study explored a multi-mechanism approach to improving the mechanical properties of a Co CrFe Mn Ni high-entropy alloy through non-equiatomic alloy design and processing.The alloy design ensures a single-phase face-centered cubic structure while lowering the stacking fault energy to encourage the formation of deformation twins and stacking faults by altering the equiatomic composition of the alloy.The processing strategy applied helped create a hierarchical grain size gradient microstructure with a high nanotwins population.This was achieved by means of rotationally accelerated shot peening(RASP).The non-equiatomic Co Cr Fe Mn Ni high-entropy alloy achieved a yield strength of 750 MPa,a tensile strength of 1050 MPa,and tensile uniform elongation of 27.5%.The toughness of the alloy was 2.53×10^(10)k J/m^(3),which is about 2 times that of the same alloy without the RASP treatment.The strength increase is attributed to the effects of grain boundary strengthening,dislocation strengthening,twin strengthening,and hetero-deformation strengthening associated with the heterogeneous microstructure of the alloy.The concurrent occurrence of the multiple deformation mechanisms,i.e.,dislocation deformation,twining deformation and microband deformation,contributes to achieving a suitable strain hardening of the alloy that helps to prevent early necking and to assure steady plastic deformation for high toughness.
