To investigate the influences of co-flowand counter-flowmodes of reactant flowarrangement on a proton exchange membrane fuel cell(PEMFC)during start-up,unsteady physical and mathematical models fully coupling the flow...To investigate the influences of co-flowand counter-flowmodes of reactant flowarrangement on a proton exchange membrane fuel cell(PEMFC)during start-up,unsteady physical and mathematical models fully coupling the flow,heat,and electrochemical reactions in a PEMFC are established.The continuity equation and momentum equation are solved by handling pressure-velocity coupling using the SIMPLE algorithm.The electrochemical reaction rates in the catalyst layers(CLs)of the cathode and anode are calculated using the Butler-Volmer equation.The multiphase mixture model describes the multiphase transport process of gas mixtures and liquid water in the fuel cell.After validation,the influences of co-flow and counter-flow modes on the PEMFC performance are investigated,including the evolution of the current density,flow field,temperature field,and reactant concentration field during start-up,as well as the steady distribution of the current density,reactant concentration,andmembrane water content when the start-up stabilizes.Co-flow and counter-flow modes influence the current density distribution and temperature distribution.On the one hand,the co-flow mode accelerates the start-up process of the PEMFC and leads to a more evenly distributed current density than the counter-flow mode.On the other hand,the temperature difference between the inlet and outlet sections of the cell is up to 10.1℃ under the co-flow mode,much larger than the 5.0℃ observed in the counter-flow mode.Accordingly,the counter-flowmode results in a more evenly distributed temperature and a lower maximum temperature than the co-flow case.Therefore,in the flow field design of a PEMFC,the reactant flow arrangements can be considered to weigh between better heat management and higher current density distribution of the cell.展开更多
A nitrogen-polarity(N-polarity)GaN-based high electron mobility transistor(HEMT)shows great potential for high-fre-quency solid-state power amplifier applications because its two-dimensional electron gas(2DEG)density ...A nitrogen-polarity(N-polarity)GaN-based high electron mobility transistor(HEMT)shows great potential for high-fre-quency solid-state power amplifier applications because its two-dimensional electron gas(2DEG)density and mobility are mini-mally affected by device scaling.However,the Schottky barrier height(SBH)of N-polarity GaN is low.This leads to a large gate leakage in N-polarity GaN-based HEMTs.In this work,we investigate the effect of annealing on the electrical characteristics of N-polarity GaN-based Schottky barrier diodes(SBDs)with Ni/Au electrodes.Our results show that the annealing time and tem-perature have a large influence on the electrical properties of N-polarity GaN SBDs.Compared to the N-polarity SBD without annealing,the SBH and rectification ratio at±5 V of the SBD are increased from 0.51 eV and 30 to 0.77 eV and 7700,respec-tively,and the ideal factor of the SBD is decreased from 1.66 to 1.54 after an optimized annealing process.Our analysis results suggest that the improvement of the electrical properties of SBDs after annealing is mainly due to the reduction of the inter-face state density between Schottky contact metals and N-polarity GaN and the increase of barrier height for the electron emis-sion from the trap state at low reverse bias.展开更多
In this paper, the issues of stochastic stability analysis and fault estimation are investigated for a class of continuoustime Markov jump piecewise-affine(PWA) systems against actuator and sensor faults. Firstly, a n...In this paper, the issues of stochastic stability analysis and fault estimation are investigated for a class of continuoustime Markov jump piecewise-affine(PWA) systems against actuator and sensor faults. Firstly, a novel mode-dependent PWA iterative learning observer with current feedback is designed to estimate the system states and faults, simultaneously, which contains both the previous iteration information and the current feedback mechanism. The auxiliary feedback channel optimizes the response speed of the observer, therefore the estimation error would converge to zero rapidly. Then, sufficient conditions for stochastic stability with guaranteed performance are demonstrated for the estimation error system, and the equivalence relations between the system information and the estimated information can be established via iterative accumulating representation.Finally, two illustrative examples containing a class of tunnel diode circuit systems are presented to fully demonstrate the effectiveness and superiority of the proposed iterative learning observer with current feedback.展开更多
MgH_(2)with a large hydrogen capacity is regarded as a promising hydrogen storage material.However,it still suffers from high thermal stability and sluggish kinetics.In this paper,highly dispersed nano-Ni has been suc...MgH_(2)with a large hydrogen capacity is regarded as a promising hydrogen storage material.However,it still suffers from high thermal stability and sluggish kinetics.In this paper,highly dispersed nano-Ni has been successfully prepared by using the polyol reduction method with an average size of 2.14 nm,which significantly improves the de/rehydrogenation properties of MgH_(2).The MgH_(2)–10wt%nano-Ni sample starts releasing H_(2)at 497 K,and roughly 6.2wt%H_(2)has been liberated at 583 K.The rehydrogenation kinetics of the sample are also greatly improved,and the adsorption capacity reaches 5.3wt%H_(2)in 1000 s at 482 K and under 3 MPa hydrogen pressure.Moreover,the activation energies of de/rehydrogenation of the MgH_(2)–10wt%nano-Ni sample are reduced to(88±2)and(87±1)kJ·mol−1,respectively.In addition,the thermal stability of the MgH_(2)–10wt%nano-Ni system is reduced by 5.5 kJ per mol H_(2)from that of pristine MgH_(2).This finding indicates that nano-Ni significantly improves both the thermodynamic and kinetic performances of the de/rehydrogenation of MgH_(2),serving as a bi-functional additive of both reagent and catalyst.展开更多
Power-to-methane(P2M)processes,by converting electricity from renewable energy to H2and then into other high value-added and energy-intense chemicals in the presence of active catalysts,have become an effective soluti...Power-to-methane(P2M)processes,by converting electricity from renewable energy to H2and then into other high value-added and energy-intense chemicals in the presence of active catalysts,have become an effective solution for energy storage.However,the fluctuating electricity from intermittent renewable energy leads to a dynamic composition of reactants for downstream methanation,which requires an excellent heterogeneous catalyst to withstand the harsh conditions.Based on these findings,the objective of this review is to classify the fundamentals and status of CO/CO_(2)methanation and identify the pathways in the presence of various catalysts for methane production.In addition,this review sheds insight into the future development and challenges of CO_(2)or CO methanation,including the deactivation mechanisms and catalyst performance under dynamically harsh conditions.Finally,we elaborated on the advantages and development prospects of P2M,and then we summarized the current stage and ongoing industrialization projects of P2M.展开更多
Developing efficient oxygen reduction reaction(ORR)catalyst is essential for the practical application of Zn-air batteries(ZABs).In this contribution,we develop a novel zeolitic imidazolate framework(ZIF)-mediated str...Developing efficient oxygen reduction reaction(ORR)catalyst is essential for the practical application of Zn-air batteries(ZABs).In this contribution,we develop a novel zeolitic imidazolate framework(ZIF)-mediated strategy to anchor Co species on N-doped carbon nanorods for efficient ORR.Featuring ultrahigh N-doping(10.29 at.%),monodisperse Co nanocrystal decoration,and well-dispersed Co-N_(x)functionalization,the obtained Co-decorated N-doped carbon nanorods(Co@NCNR)exhibit a decent ORR performance comparable to commercial Pt/C in alkaline media.Aqueous ZABs have been assembled using Co@NCNR as the cathode catalyst.The assembled ZABs manifest high initial open-circuit voltage as well as high energy density.In addition,the Co@NCNR also demonstrates ideal ORR performance in quasi-solid-state ZABs.展开更多
Electronic fibers used to fabricate wearable triboelectric nanogenerator(TENG) for harvesting human mechanical energy have been extensively explored. However, little attention is paid to their mutual advantages of env...Electronic fibers used to fabricate wearable triboelectric nanogenerator(TENG) for harvesting human mechanical energy have been extensively explored. However, little attention is paid to their mutual advantages of environmental friendliness, mechanical properties, and stability. Here, we report a super-strong, biodegradable, and washable cellulose-based conductive macrofibers, which is prepared by wet-stretching and wet-twisting bacterial cellulose hydrogel incorporated with carbon nanotubes and polypyrrole. The cellulose-based conductive macrofibers possess high tensile strength of 449 MPa(able to lift 2 kg weights), good electrical conductivity(~ 5.32 S cm^(-1)), and excellent stability(Tensile strength and conductivity only decrease by 6.7% and 8.1% after immersing in water for 1 day). The degradation experiment demonstrates macrofibers can be degraded within 108 h in the cellulase solution. The designed fabric-based TENG from the cellulose-base conductive macrofibers shows a maximum open-circuit voltage of 170 V, short-circuit current of 0.8 μA, and output power at 352 μW, which is capable of powering the commercial electronics by charging the capacitors. More importantly, the fabric-based TENGs can be attached to the human body and work as self-powered sensors to effectively monitor human motions. This study suggests the potential of biodegradable, super-strong, and washable conductive cellulose-based fiber for designing eco-friendly fabric-based TENG for energy harvesting and biomechanical monitoring.展开更多
Purpose:To compare the clinical findings, tear film function and impression cytology between patients with active and inactive Thyroid Eye Disease (TED). Methods:.A total of 56 patients with TED and 30 controls were r...Purpose:To compare the clinical findings, tear film function and impression cytology between patients with active and inactive Thyroid Eye Disease (TED). Methods:.A total of 56 patients with TED and 30 controls were recruited in this prospective observational cohort study. TED patients were divided into active TED and inactive TED types according to a seven-point modified formulation of the Clinical Activity Score (CAS). All participants underwent full eye examinations including Ocular Surface Disease Index (OSDI) score, tear film break-up time (TBUT), fluorescein staining and Schirmer I test. Thirty nine patients with thyroid-associated orbitopathy.(TAO) received Nelson's grade with conjunctival impression cytology. Proptosis, palpebral fissure width and lagophthalmos were assessed. Results:.Ocular surface parameters including proptosis, palpebral fissure width and lagophthalmos did not differ between active and inactive TED patients(P>0.05). Both active and inactive TED patients obtained higher fluorescein staining scores, lower TBUT scores and significantly lower Schirmer test scores than those of controls (P<0.001 for all). Additionally, the TBUT score was significantly lower and the OSDI score significantly higher in the active TED group compared with those in the inactive TED group (P<0.001 for both). Impression cytology revealed a higher proportion of grade 2-3 changes in the active TED group compared with the inactive TED group(P<0.001). Conclusion:.Orbital inflammation in TED patients may lead to decreased tear film stability and ocular surface squamous metaplasia.展开更多
The intrinsic stochasticity of resistance switching process is one of the holdblocks for using memristor as a fundamental element in the next-generation nonvolatile memory.However,such a weakness can be used as an ass...The intrinsic stochasticity of resistance switching process is one of the holdblocks for using memristor as a fundamental element in the next-generation nonvolatile memory.However,such a weakness can be used as an asset for generating the random bits,which is valuable in a hardware security system.In this work,a forming-free electronic bipolar Pt/Ti/Ta2O5/Pt memristor is successfully fabricated to investigate the merits of generating random bits in such a device.The resistance switching mechanism of the fabricated device is ascribed to the electric field conducted electrons trapping/de-trapping in the deep-energy-level traps produced by the"oxygen grabbing"process.The stochasticity of the electrons trapping/detrapping governs the random distribution of the set/reset switching voltages of the device,making a single memristor act as a random bit in which the resistance of the device represents information and the applied voltage pulse serves as the triggering signal.The physical implementation of such a random process provides a method of generating the random bits based on memristors in hardware security applications.展开更多
As indoor horticulture gathers momentum,electric(also termed artificial)lighting systems with the ability to generate specific and tunable wavelengths have been developed and applied.While the effects of light quality...As indoor horticulture gathers momentum,electric(also termed artificial)lighting systems with the ability to generate specific and tunable wavelengths have been developed and applied.While the effects of light quality on plant growth and development have been studied,authoritative and reliable sets of light formulae tailored for the cultivation of economically important plants and plant traits are lacking as light qualities employed across laboratories are inconsistent.This is due,at least in part,to the lack of molecular data for plants examined under electric lights in indoor environments.It has hampered progress in the field of indoor horticulture,in particular,the transition from small-scale indoor farming to commercial plant factories.Here,we review the effects of light quality on model and crop plants studied from a physiological,physical and biochemical perspective,and explain how functional genomics can be employed in tandem to generate a wealth of molecular data specific for plants cultivated under indoor lighting.We also review the current state of lighting technologies in indoor horticulture specifically discussing how recent narrow-bandwidth lighting technologies can be tailored to cultivate economically valuable plant species and traits.Knowledge gained from a complementary phenotypic and functional genomics approach can be harvested not only for economical gains but also for sustainable food production.We believe that this review serves as a platform that guides future light-related plant research.展开更多
An improved measurement method of circularly-polarized (CP) antennas based on linear-component amplitudes is proposed in this paper. By utilizing two sets of orthogonal linear polarization (LP) amplitudes, measurement...An improved measurement method of circularly-polarized (CP) antennas based on linear-component amplitudes is proposed in this paper. By utilizing two sets of orthogonal linear polarization (LP) amplitudes, measurement on axial ratio (AR) of CP antennas can be realized without phase information. However, the rotation sense of the co-polarization cannot be determined due to the absence of the phase information. Above problem is discussed here for the first time, and a solution is presented to determine the rotation sense of the co-polarization by using common auxiliary CP antennas. In addition, there will be some particular cases with large errors in actual measurement. Here a corresponding solution method is given. Finally, co-polarization and cross-polarization patterns can be further obtained from AR results. To verify this improved method, a self-developed CP microstrip array was measured. The measured results are in agreement with the simulated results, which prove this method is correct, effective and practical.展开更多
Organic and carbon-based lithium-ion batteries possess abundant resources,nontoxicity,environmental friendliness,and high performance,and they have been widely studied in the past decades.However,it remains a challeng...Organic and carbon-based lithium-ion batteries possess abundant resources,nontoxicity,environmental friendliness,and high performance,and they have been widely studied in the past decades.However,it remains a challenge to construct such batteries with high capacity,high cycling stability,and high conductivity simultaneously.Here,we elaborately design and integrate organic polymer(p-FcPZ) with graphene network to create a hybrid material(p-FcPZ@G) for high-performance lithium-ion batteries(LIBs).The bi-polar polymer p-FcPZ containing multiple redox-active sites endows p-FcPZ@G with both remarkable cycling stability and high capacity.The porous conductive graphene network with a large surface area facilitates rapid ions/electrons transportation,resulting in superior rate performance.Therefore,the half-cell based on p-FcPZ@G cathode exhibits simultaneously high capacity(~250 mA h g^(-1) at 50 mA g^(-1)),excellent cycling stability(retention of 99.999% per cycle for 10,000 cycles at 2,000 mA g^(-1)) and superior rate performance.Additionally,the graphene-based full cell assembled with p-FcPZ@G cathode and graphene anode also demonstrates comprehensively high electrochemical performance.展开更多
The efficient separation of acetylene(C_(2)H_(2))from carbon dioxide(CO_(2))and CnH_(4)(n=1 and 2)to manufacture high purity C_(2)H_(2)and recover other light hydrocarbons is technologically important,while posing sig...The efficient separation of acetylene(C_(2)H_(2))from carbon dioxide(CO_(2))and CnH_(4)(n=1 and 2)to manufacture high purity C_(2)H_(2)and recover other light hydrocarbons is technologically important,while posing significant challenges.Herein,we reported a new TiF62−anion(TIFSIX)pillared metal-organic framework(MOF)ZNU-5(ZNU=Zhejiang Normal University)with ultramicropores for highly selective C_(2)H_(2)capture with low adsorption heat through gate opening based molecular sieving effect.ZNU-5 takes up a large amount of C_(2)H_(2)(128.6 cm^(3)/g)at 1.0 bar and 298 K but excludes CO_(2),CH_(4),and C_(2)H_(4).Such high capacity has never been realized in MOFs with molecular sieving.The breakthrough experiments further confirmed the highly selective C_(2)H_(2)separation performance from multi-component gas mixtures.3.3,2.8,and 2.2 mmol/g of C_(2)H_(2)is captured at ZNU-5 from equimolar C_(2)H_(2)/CO_(2),C_(2)H_(2)/CO_(2)/CH_(4),and C_(2)H_(2)/CO_(2)/CH_(4)/C_(2)H_(4)mixtures,respectively.Furthermore,2.6,2.0,and 1.5 mmol/g of>98%purity C_(2)H_(2)can be recycled from the desorption process.Combining high working capacity,low adsorption heat,as well as good recyclability,ZNU-5 is promising for C_(2)H_(2)purification.展开更多
Using the method of structural finite element topology optimization and analysis of the hindwings of Trypoxylus dichotomus,this work identified the main loading force transmission path and designed the initial structu...Using the method of structural finite element topology optimization and analysis of the hindwings of Trypoxylus dichotomus,this work identified the main loading force transmission path and designed the initial structure of a bionic flexible wing.A structural design scheme of the vibration damping unit was proposed,and the structural mechanics and modal vibration characteristics were simulated and analyzed.3D printing technology was used to manufacture the designed bionic wing skeleton,which was combined with two kinds of wing membrane materials.The Flapping Wing Micro-aerial Vehicle(FWMAV)transmission mechanism vibration characteristics were observed and analyzed by a high-speed digital camera.A triaxial force transducer was used to record the force vibration of the flexible bionic wing flapping in a wind tunnel.A wavelet processing method was used to process and analyze the force signal.The results showed that the force amplitude was more stable,the waveform roughness was the lowest,and the peak shaving phenomenon at the z-axis was the least obvious for the bionic flexible wing model that combined the topology-optimized bionic wing skeleton with a polyamide elastic membrane.This was determined to be the most suitable design scheme for the wings of FWMAVs.展开更多
Portable energy solutions are highly desired in the era of the Internet of Things for powering various distributed micro-electronic devices.At the same time,the energy crisis and catastrophic global warming are becomi...Portable energy solutions are highly desired in the era of the Internet of Things for powering various distributed micro-electronic devices.At the same time,the energy crisis and catastrophic global warming are becoming serious problems in the world,emphasizing the urgent need for clean and renewable energy.Here,we report a low-cost,high-performance,and portable hand-driven whirligig structured triboelectric–electromagnetic hybrid nanogenerator(whirligig-HNG)for multi-strategy energy harvesting.The whirligig-HNG comprises a dynamic supercoiling TENG via the pulling-strings and inner-distributed EMGs(variable number)in the rotator.The whirligig structure can readily convert linear displacement in low frequency into rotary motion in extremely high frequency.Based on this ingenious design,the whirligig-HNG is capable to harvest the triboelectric energy from the supercoiling/uncoiling process from the pulling strings and simultaneously utilize the high-frequency rotation energy via electromagnetic induction.We have systematically investigated the working mecha-nism of the whirligig-HNG for coupled energy harvesting and compared the individual characteristics of TENG and EMG.The whirligig-HNG is successfully demonstrated to light up more than 100 commercial light-emitting diodes(LEDs)and drive portable electronics.This research presents the enormous potential of whirligig-HNG as a manual and portable power supply for powering various portable electronics.展开更多
基金supported by the Projects of Talents Recruitment of Guangdong University of Petrochemical Technology(No.2018rc14)Maoming City Science and Technology Plan Project(Nos.210427094551264 and 220415004552411).
文摘To investigate the influences of co-flowand counter-flowmodes of reactant flowarrangement on a proton exchange membrane fuel cell(PEMFC)during start-up,unsteady physical and mathematical models fully coupling the flow,heat,and electrochemical reactions in a PEMFC are established.The continuity equation and momentum equation are solved by handling pressure-velocity coupling using the SIMPLE algorithm.The electrochemical reaction rates in the catalyst layers(CLs)of the cathode and anode are calculated using the Butler-Volmer equation.The multiphase mixture model describes the multiphase transport process of gas mixtures and liquid water in the fuel cell.After validation,the influences of co-flow and counter-flow modes on the PEMFC performance are investigated,including the evolution of the current density,flow field,temperature field,and reactant concentration field during start-up,as well as the steady distribution of the current density,reactant concentration,andmembrane water content when the start-up stabilizes.Co-flow and counter-flow modes influence the current density distribution and temperature distribution.On the one hand,the co-flow mode accelerates the start-up process of the PEMFC and leads to a more evenly distributed current density than the counter-flow mode.On the other hand,the temperature difference between the inlet and outlet sections of the cell is up to 10.1℃ under the co-flow mode,much larger than the 5.0℃ observed in the counter-flow mode.Accordingly,the counter-flowmode results in a more evenly distributed temperature and a lower maximum temperature than the co-flow case.Therefore,in the flow field design of a PEMFC,the reactant flow arrangements can be considered to weigh between better heat management and higher current density distribution of the cell.
基金This work was supported by the National Key R&D Program of China(Nos.2022YFB3605205,2021YFB3601000,and 2021YFB3601002)the National Natural Science Foundation of China(Nos.U22A20134,62074069,62104078,and 62104079)the Science and Technology Developing Project of Jilin Province(Nos.20220201065GX,20230101053JC,and 20220101119JC).
文摘A nitrogen-polarity(N-polarity)GaN-based high electron mobility transistor(HEMT)shows great potential for high-fre-quency solid-state power amplifier applications because its two-dimensional electron gas(2DEG)density and mobility are mini-mally affected by device scaling.However,the Schottky barrier height(SBH)of N-polarity GaN is low.This leads to a large gate leakage in N-polarity GaN-based HEMTs.In this work,we investigate the effect of annealing on the electrical characteristics of N-polarity GaN-based Schottky barrier diodes(SBDs)with Ni/Au electrodes.Our results show that the annealing time and tem-perature have a large influence on the electrical properties of N-polarity GaN SBDs.Compared to the N-polarity SBD without annealing,the SBH and rectification ratio at±5 V of the SBD are increased from 0.51 eV and 30 to 0.77 eV and 7700,respec-tively,and the ideal factor of the SBD is decreased from 1.66 to 1.54 after an optimized annealing process.Our analysis results suggest that the improvement of the electrical properties of SBDs after annealing is mainly due to the reduction of the inter-face state density between Schottky contact metals and N-polarity GaN and the increase of barrier height for the electron emis-sion from the trap state at low reverse bias.
基金supported in part by the National Natural Science Foundation of China (62222310, U1813201, 61973131, 62033008)the Research Fund for the Taishan Scholar Project of Shandong Province of China+2 种基金the NSFSD(ZR2022ZD34)Japan Society for the Promotion of Science (21K04129)Fujian Outstanding Youth Science Fund (2020J06022)。
文摘In this paper, the issues of stochastic stability analysis and fault estimation are investigated for a class of continuoustime Markov jump piecewise-affine(PWA) systems against actuator and sensor faults. Firstly, a novel mode-dependent PWA iterative learning observer with current feedback is designed to estimate the system states and faults, simultaneously, which contains both the previous iteration information and the current feedback mechanism. The auxiliary feedback channel optimizes the response speed of the observer, therefore the estimation error would converge to zero rapidly. Then, sufficient conditions for stochastic stability with guaranteed performance are demonstrated for the estimation error system, and the equivalence relations between the system information and the estimated information can be established via iterative accumulating representation.Finally, two illustrative examples containing a class of tunnel diode circuit systems are presented to fully demonstrate the effectiveness and superiority of the proposed iterative learning observer with current feedback.
基金financially supported by the National Natural Science Foundation of China (No. 52071177)the Natural Science Foundation of Guangxi, China (No. 2020GXNSFAA297074)+1 种基金the Jiangsu Key Laboratory for Advanced Metallic Materials (No. BM2007204)the Guangxi Key Laboratory of Information Materials (No. 211021-K)
文摘MgH_(2)with a large hydrogen capacity is regarded as a promising hydrogen storage material.However,it still suffers from high thermal stability and sluggish kinetics.In this paper,highly dispersed nano-Ni has been successfully prepared by using the polyol reduction method with an average size of 2.14 nm,which significantly improves the de/rehydrogenation properties of MgH_(2).The MgH_(2)–10wt%nano-Ni sample starts releasing H_(2)at 497 K,and roughly 6.2wt%H_(2)has been liberated at 583 K.The rehydrogenation kinetics of the sample are also greatly improved,and the adsorption capacity reaches 5.3wt%H_(2)in 1000 s at 482 K and under 3 MPa hydrogen pressure.Moreover,the activation energies of de/rehydrogenation of the MgH_(2)–10wt%nano-Ni sample are reduced to(88±2)and(87±1)kJ·mol−1,respectively.In addition,the thermal stability of the MgH_(2)–10wt%nano-Ni system is reduced by 5.5 kJ per mol H_(2)from that of pristine MgH_(2).This finding indicates that nano-Ni significantly improves both the thermodynamic and kinetic performances of the de/rehydrogenation of MgH_(2),serving as a bi-functional additive of both reagent and catalyst.
基金funded by the National Key Research and Development Program of China(2019YFA0405602)the Hefei Science Center,CAS(2020HSC-KPRD001,2021HSC-UE005)the DNL Cooperation Fund,CAS(DNL202005)。
文摘Power-to-methane(P2M)processes,by converting electricity from renewable energy to H2and then into other high value-added and energy-intense chemicals in the presence of active catalysts,have become an effective solution for energy storage.However,the fluctuating electricity from intermittent renewable energy leads to a dynamic composition of reactants for downstream methanation,which requires an excellent heterogeneous catalyst to withstand the harsh conditions.Based on these findings,the objective of this review is to classify the fundamentals and status of CO/CO_(2)methanation and identify the pathways in the presence of various catalysts for methane production.In addition,this review sheds insight into the future development and challenges of CO_(2)or CO methanation,including the deactivation mechanisms and catalyst performance under dynamically harsh conditions.Finally,we elaborated on the advantages and development prospects of P2M,and then we summarized the current stage and ongoing industrialization projects of P2M.
基金supported by the National Natural Science Foundation of China(52072283)the National Key Research and Development Program of China(2020YFA0715000)+1 种基金Shenzhen Fundamental Research Program(JCYJ20190809114409397)supported by the Fundamental Research Funds for the Central Universities(WUT:2021III016GX).
文摘Developing efficient oxygen reduction reaction(ORR)catalyst is essential for the practical application of Zn-air batteries(ZABs).In this contribution,we develop a novel zeolitic imidazolate framework(ZIF)-mediated strategy to anchor Co species on N-doped carbon nanorods for efficient ORR.Featuring ultrahigh N-doping(10.29 at.%),monodisperse Co nanocrystal decoration,and well-dispersed Co-N_(x)functionalization,the obtained Co-decorated N-doped carbon nanorods(Co@NCNR)exhibit a decent ORR performance comparable to commercial Pt/C in alkaline media.Aqueous ZABs have been assembled using Co@NCNR as the cathode catalyst.The assembled ZABs manifest high initial open-circuit voltage as well as high energy density.In addition,the Co@NCNR also demonstrates ideal ORR performance in quasi-solid-state ZABs.
基金financially supported by BRICS STI Framework Programme 3rd call 2019the National Key Research and Development Program of China(Grant No.2018YFE0123700)+3 种基金the National Natural Science Foundation of China(Grant Nos.51973076 and 52073031)State Key Laboratory of New Textile Materials and Advanced Processing Technologies(Grant No.FZ2021005)the Fundamental Research Funds for the Central Universities(Grant Nos.2020kfyXJJS035,WUT2018IVB006,and Z191100001119047)。
文摘Electronic fibers used to fabricate wearable triboelectric nanogenerator(TENG) for harvesting human mechanical energy have been extensively explored. However, little attention is paid to their mutual advantages of environmental friendliness, mechanical properties, and stability. Here, we report a super-strong, biodegradable, and washable cellulose-based conductive macrofibers, which is prepared by wet-stretching and wet-twisting bacterial cellulose hydrogel incorporated with carbon nanotubes and polypyrrole. The cellulose-based conductive macrofibers possess high tensile strength of 449 MPa(able to lift 2 kg weights), good electrical conductivity(~ 5.32 S cm^(-1)), and excellent stability(Tensile strength and conductivity only decrease by 6.7% and 8.1% after immersing in water for 1 day). The degradation experiment demonstrates macrofibers can be degraded within 108 h in the cellulase solution. The designed fabric-based TENG from the cellulose-base conductive macrofibers shows a maximum open-circuit voltage of 170 V, short-circuit current of 0.8 μA, and output power at 352 μW, which is capable of powering the commercial electronics by charging the capacitors. More importantly, the fabric-based TENGs can be attached to the human body and work as self-powered sensors to effectively monitor human motions. This study suggests the potential of biodegradable, super-strong, and washable conductive cellulose-based fiber for designing eco-friendly fabric-based TENG for energy harvesting and biomechanical monitoring.
基金supported by a grant from the Projectof Technological Plan of Guangdong Province.(No..2010B031100012)Guangdong Natural Science Foundation(9151008901000102)
文摘Purpose:To compare the clinical findings, tear film function and impression cytology between patients with active and inactive Thyroid Eye Disease (TED). Methods:.A total of 56 patients with TED and 30 controls were recruited in this prospective observational cohort study. TED patients were divided into active TED and inactive TED types according to a seven-point modified formulation of the Clinical Activity Score (CAS). All participants underwent full eye examinations including Ocular Surface Disease Index (OSDI) score, tear film break-up time (TBUT), fluorescein staining and Schirmer I test. Thirty nine patients with thyroid-associated orbitopathy.(TAO) received Nelson's grade with conjunctival impression cytology. Proptosis, palpebral fissure width and lagophthalmos were assessed. Results:.Ocular surface parameters including proptosis, palpebral fissure width and lagophthalmos did not differ between active and inactive TED patients(P>0.05). Both active and inactive TED patients obtained higher fluorescein staining scores, lower TBUT scores and significantly lower Schirmer test scores than those of controls (P<0.001 for all). Additionally, the TBUT score was significantly lower and the OSDI score significantly higher in the active TED group compared with those in the inactive TED group (P<0.001 for both). Impression cytology revealed a higher proportion of grade 2-3 changes in the active TED group compared with the inactive TED group(P<0.001). Conclusion:.Orbital inflammation in TED patients may lead to decreased tear film stability and ocular surface squamous metaplasia.
基金Project supported by the National Natural Science Foundation of China(Grant No.61832007)the National Key Research and Development Program of China(Grant No.2018YFB1003304)。
文摘The intrinsic stochasticity of resistance switching process is one of the holdblocks for using memristor as a fundamental element in the next-generation nonvolatile memory.However,such a weakness can be used as an asset for generating the random bits,which is valuable in a hardware security system.In this work,a forming-free electronic bipolar Pt/Ti/Ta2O5/Pt memristor is successfully fabricated to investigate the merits of generating random bits in such a device.The resistance switching mechanism of the fabricated device is ascribed to the electric field conducted electrons trapping/de-trapping in the deep-energy-level traps produced by the"oxygen grabbing"process.The stochasticity of the electrons trapping/detrapping governs the random distribution of the set/reset switching voltages of the device,making a single memristor act as a random bit in which the resistance of the device represents information and the applied voltage pulse serves as the triggering signal.The physical implementation of such a random process provides a method of generating the random bits based on memristors in hardware security applications.
基金We would like to acknowledge financial support from the Office of Research and Sponsored Programs of Wenzhou-Kean UniversityC.M.is supported by the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No.752418.
文摘As indoor horticulture gathers momentum,electric(also termed artificial)lighting systems with the ability to generate specific and tunable wavelengths have been developed and applied.While the effects of light quality on plant growth and development have been studied,authoritative and reliable sets of light formulae tailored for the cultivation of economically important plants and plant traits are lacking as light qualities employed across laboratories are inconsistent.This is due,at least in part,to the lack of molecular data for plants examined under electric lights in indoor environments.It has hampered progress in the field of indoor horticulture,in particular,the transition from small-scale indoor farming to commercial plant factories.Here,we review the effects of light quality on model and crop plants studied from a physiological,physical and biochemical perspective,and explain how functional genomics can be employed in tandem to generate a wealth of molecular data specific for plants cultivated under indoor lighting.We also review the current state of lighting technologies in indoor horticulture specifically discussing how recent narrow-bandwidth lighting technologies can be tailored to cultivate economically valuable plant species and traits.Knowledge gained from a complementary phenotypic and functional genomics approach can be harvested not only for economical gains but also for sustainable food production.We believe that this review serves as a platform that guides future light-related plant research.
文摘An improved measurement method of circularly-polarized (CP) antennas based on linear-component amplitudes is proposed in this paper. By utilizing two sets of orthogonal linear polarization (LP) amplitudes, measurement on axial ratio (AR) of CP antennas can be realized without phase information. However, the rotation sense of the co-polarization cannot be determined due to the absence of the phase information. Above problem is discussed here for the first time, and a solution is presented to determine the rotation sense of the co-polarization by using common auxiliary CP antennas. In addition, there will be some particular cases with large errors in actual measurement. Here a corresponding solution method is given. Finally, co-polarization and cross-polarization patterns can be further obtained from AR results. To verify this improved method, a self-developed CP microstrip array was measured. The measured results are in agreement with the simulated results, which prove this method is correct, effective and practical.
基金supported by the National Natural Science Foundation of China (52090034)the Ministry of Science and Technology of China (2020YFA0711500)the Higher Education Discipline Innovation Project (111 Project B12015)。
基金supported by the National Key Research and Development Program of China(2021YFA1200500)the National Natural Science Foundation of China(61925402,62090032,62104039,and 62304042)+5 种基金the Science and Technology Commission of Shanghai Municipality(19JC1416600)China Postdoctoral Science Foundation(2022M720032)Shanghai Post-Doctoral Excellence Program(2022091)Sailing Program(23YF1402100)the Natural Science Foundation of Shanghai(21ZR1405700)the Shanghai Science and Technology Commission “Explorer Project”(22TS1401500)。
基金supported by the National Natural Science Foundation of China (52090034)the Ministry of Science and Technology of China (2020YFA0711500)the Higher Education Discipline Innovation Project (B12015)。
文摘Organic and carbon-based lithium-ion batteries possess abundant resources,nontoxicity,environmental friendliness,and high performance,and they have been widely studied in the past decades.However,it remains a challenge to construct such batteries with high capacity,high cycling stability,and high conductivity simultaneously.Here,we elaborately design and integrate organic polymer(p-FcPZ) with graphene network to create a hybrid material(p-FcPZ@G) for high-performance lithium-ion batteries(LIBs).The bi-polar polymer p-FcPZ containing multiple redox-active sites endows p-FcPZ@G with both remarkable cycling stability and high capacity.The porous conductive graphene network with a large surface area facilitates rapid ions/electrons transportation,resulting in superior rate performance.Therefore,the half-cell based on p-FcPZ@G cathode exhibits simultaneously high capacity(~250 mA h g^(-1) at 50 mA g^(-1)),excellent cycling stability(retention of 99.999% per cycle for 10,000 cycles at 2,000 mA g^(-1)) and superior rate performance.Additionally,the graphene-based full cell assembled with p-FcPZ@G cathode and graphene anode also demonstrates comprehensively high electrochemical performance.
基金support by the National Natural Science Foundation of China(No.21908193)Jinhua Industrial Key Project(No.2021A22648)+2 种基金S.D.acknowledged the financial support by the National Natural Science Foundation of China(No.21871231)the Special Funds for Basic Scientific Research of Zhejiang University(Nos.2019QNA3010 and K20210335)support by the National Natural Science Foundation of China(No.22205207).
文摘The efficient separation of acetylene(C_(2)H_(2))from carbon dioxide(CO_(2))and CnH_(4)(n=1 and 2)to manufacture high purity C_(2)H_(2)and recover other light hydrocarbons is technologically important,while posing significant challenges.Herein,we reported a new TiF62−anion(TIFSIX)pillared metal-organic framework(MOF)ZNU-5(ZNU=Zhejiang Normal University)with ultramicropores for highly selective C_(2)H_(2)capture with low adsorption heat through gate opening based molecular sieving effect.ZNU-5 takes up a large amount of C_(2)H_(2)(128.6 cm^(3)/g)at 1.0 bar and 298 K but excludes CO_(2),CH_(4),and C_(2)H_(4).Such high capacity has never been realized in MOFs with molecular sieving.The breakthrough experiments further confirmed the highly selective C_(2)H_(2)separation performance from multi-component gas mixtures.3.3,2.8,and 2.2 mmol/g of C_(2)H_(2)is captured at ZNU-5 from equimolar C_(2)H_(2)/CO_(2),C_(2)H_(2)/CO_(2)/CH_(4),and C_(2)H_(2)/CO_(2)/CH_(4)/C_(2)H_(4)mixtures,respectively.Furthermore,2.6,2.0,and 1.5 mmol/g of>98%purity C_(2)H_(2)can be recycled from the desorption process.Combining high working capacity,low adsorption heat,as well as good recyclability,ZNU-5 is promising for C_(2)H_(2)purification.
基金supported by the National Natural Science Foundation of China(grant number 31970454)the Aviation Science Foundation of China(2020Z0740R4001)+1 种基金the Graduate Innovation Fund of Jilin University(2022189)Undergraduate Innovation and Entrepreneurship Training Program Project of Jilin University(S202210183259).
文摘Using the method of structural finite element topology optimization and analysis of the hindwings of Trypoxylus dichotomus,this work identified the main loading force transmission path and designed the initial structure of a bionic flexible wing.A structural design scheme of the vibration damping unit was proposed,and the structural mechanics and modal vibration characteristics were simulated and analyzed.3D printing technology was used to manufacture the designed bionic wing skeleton,which was combined with two kinds of wing membrane materials.The Flapping Wing Micro-aerial Vehicle(FWMAV)transmission mechanism vibration characteristics were observed and analyzed by a high-speed digital camera.A triaxial force transducer was used to record the force vibration of the flexible bionic wing flapping in a wind tunnel.A wavelet processing method was used to process and analyze the force signal.The results showed that the force amplitude was more stable,the waveform roughness was the lowest,and the peak shaving phenomenon at the z-axis was the least obvious for the bionic flexible wing model that combined the topology-optimized bionic wing skeleton with a polyamide elastic membrane.This was determined to be the most suitable design scheme for the wings of FWMAVs.
基金supported by the National Key Research and Development Program of China(2021YFB3200304)the National Natural Science Foundation of China(52073031)+2 种基金Beijing Nova Program(Z191100001119047,Z211100002121148)Fundamental Research Funds for the Central Universities(E0EG6801X2)the“Hundred Talents Program”of the Chinese Academy of Science.
文摘Portable energy solutions are highly desired in the era of the Internet of Things for powering various distributed micro-electronic devices.At the same time,the energy crisis and catastrophic global warming are becoming serious problems in the world,emphasizing the urgent need for clean and renewable energy.Here,we report a low-cost,high-performance,and portable hand-driven whirligig structured triboelectric–electromagnetic hybrid nanogenerator(whirligig-HNG)for multi-strategy energy harvesting.The whirligig-HNG comprises a dynamic supercoiling TENG via the pulling-strings and inner-distributed EMGs(variable number)in the rotator.The whirligig structure can readily convert linear displacement in low frequency into rotary motion in extremely high frequency.Based on this ingenious design,the whirligig-HNG is capable to harvest the triboelectric energy from the supercoiling/uncoiling process from the pulling strings and simultaneously utilize the high-frequency rotation energy via electromagnetic induction.We have systematically investigated the working mecha-nism of the whirligig-HNG for coupled energy harvesting and compared the individual characteristics of TENG and EMG.The whirligig-HNG is successfully demonstrated to light up more than 100 commercial light-emitting diodes(LEDs)and drive portable electronics.This research presents the enormous potential of whirligig-HNG as a manual and portable power supply for powering various portable electronics.
