P2-type layered oxide Na_(2/3)Ni_(1/3)Mn_(2/3)O_(2)(NM)is a promising cathode material for sodium-ion batteries(SIBs).However,the severe irreversible phase transition,sluggish Na+diffusion kinetics,and interfacial sid...P2-type layered oxide Na_(2/3)Ni_(1/3)Mn_(2/3)O_(2)(NM)is a promising cathode material for sodium-ion batteries(SIBs).However,the severe irreversible phase transition,sluggish Na+diffusion kinetics,and interfacial side reactions at high-voltage result in grievous capacity degradation and inferior electrochemical performance.Herein,a dual-function strategy of entropy tuning and artificial cathode electrolyte interface(CEI)layer construction is reported to generate a novel P2-type medium-entropy Na_(0.75)Li_(0.1)Mg_(0.05)Ni_(0.18)Mn_(0.66)Ta_(0.01)O_(2)with NaTaO_(3)surface modification(LMNMT)to address the aforementioned issues.In situ X-ray diffraction reveals that LMNMT exhibits a near zero-strain phase transition with a volume change of only 1.4%,which is significantly lower than that of NM(20.9%),indicating that entropy tuning effectively suppresses irreversible phase transitions and enhances ion diffusion.Kinetic analysis and post-cycling interfacial characterization further confirm that the artificial CEI layer promotes the formation of a stable,thin NaF-rich CEI and reduces interfacial side reactions,thereby further enhancing ion transport kinetics and surface/interface stability.Consequently,the LMNMT electrode exhibits outstanding rate capability(46 mA h g^(−1)at 20 C)and cycling stability(89.5%capacity retention after 200 cycles at 2 C)within the voltage range of 2–4.35 V.The LMNMT also exhibits superior all-climate performance and air stability.This study provides a novel path for the design of high-voltage cathode materials for SIBs.展开更多
The practical application of room-temperature sodium-sulfur(RT Na-S)batteries is hindered by sluggish reaction kinetics and deleterious side reactions.To address these challenges,a defective carbon is designed as a su...The practical application of room-temperature sodium-sulfur(RT Na-S)batteries is hindered by sluggish reaction kinetics and deleterious side reactions.To address these challenges,a defective carbon is designed as a sulfur host through a simple temperature-controlled method.The abundant porosity and surface roughness enhance sulfur encapsulation and mitigate side reactions.Prominently,highly disordered structure facilitates the chemical adsorption towards NaPSs and accelerates sulfur conversion.Furthermore,electrochemical characterizations reveal that concentration polarization during the formation of long-chain NaPSs emerges as the key polarization and activation polarization dominates the nucleation of Na_(2)S during discharge,while they both significantly affect the formation of S_(8)/long-chain NaPSs during charge.Owing to the improved adsorption capability and electrocalatytic sites,S/CZ-900presents lower concentration polarization and activation polarization during both discharge and charge.Consequently,S/CZ-900 cathode achieves 1031,914,and 671 mAh g^(-1)at 1,2,and 5 C.The cathode with a high sulfur loading of 6.4 mg cm^(-2)delivers an impressive areal capacity of 14.3 mAh cm^(-2).Moreover,the S/CZ-900||Na/CZ-900(Al)full cell exhibits robust cycling stability,maintaining 1094 mAh g^(-1)after 40 cycles at 0.1 C.The insights provide a workable solution of metal-free carbonaceous host materials for the evolution of RT Na-S batteries.展开更多
Low-temperature assembly of MXene nanosheets into three-dimensional(3D) robust aerogels addresses the crucial stability concern of the nano-building blocks during the fabrication process,which is of key importance for...Low-temperature assembly of MXene nanosheets into three-dimensional(3D) robust aerogels addresses the crucial stability concern of the nano-building blocks during the fabrication process,which is of key importance for transforming the fascinating properties at the nanoscale into the macroscopic scale for practical applications.Herein,suitable cross-linking agents(amino-propyltriethoxysilane,Mn^(2+),Fe^(2+),Zn^(2+),and Co^(2+)) as interfacial mediators to engineer the interlayer interactions are reported to realize the graphene oxide(GO)-assisted assembly of Ti_(3)C_(2)T_(x) MXene aerogel at room temperature.This elaborate aerogel construction not only suppresses the oxidation degradation of Ti_(3)C_(2)T_(x) but also generates porous aerogels with a high Ti_(3)C_(2)T_(x) content(87 wt%) and robustness,thereby guaranteeing the functional accessibility of Ti_(3)C_(2)T_(x) nanosheets and operational reliability as integrated functional materials.In combination with a further sulfur modification,the Ti_(3)C_(2)T_(x) aerogel electrode shows promising electrochemical performances as the freestanding anode for sodium-ion storage.Even at an ultrahigh loading mass of 12.3 mg cm^(-2),a pronounced areal capacity of 1.26 mAh cm^(-2) at a current density of 0.1 A g^(-1) has been achieved,which is of practical significance.This work conceptually suggests a new way to exert the utmost surface functionalities of MXenes in 3D monolithic form and can be an inspiring scaffold to promote the application of MXenes in different areas.展开更多
Four common types of additives for polymer membrane preparation including organic macromolecule and micromolecule additives, inorganic salts and acids, and the strong non-solvent H2 O were used to prepare poly（vinyli...Four common types of additives for polymer membrane preparation including organic macromolecule and micromolecule additives, inorganic salts and acids, and the strong non-solvent H2 O were used to prepare poly（vinylidene fluoride-co-chlorotrifluoroethylene）（PVDF-CTFE） hydrophobic flat-sheet membranes. Membrane properties including morphology, porosity, hydrophobicity, pore size and pore distribution were investigated, and the permeability was evaluated via direct contact membrane distillation（DCMD） of 3.5 g/L Na Cl solution in a DCMD configuration. Both inorganic and organic micromolecule additives were found to slightly influence membrane hydrophobicity. Polyethylene glycol（PEG）,organic acids, Li Cl, Mg Cl2, and Li Cl/H2 O mixtures were proved to be effective additives to PVDF-CTFE membranes due to their pore-controlling effects and the capacity to improve the properties and performance of the resultant membranes. The occurrence of a pre-gelation process showed that when organic and inorganic micromolecules were added to PVDF-CTFE solution, the resultant membranes presented a high interconnectivity structure. The membrane prepared with dibutyl phthalate（DBP） showed a nonporous surface and symmetrical cross-section. When H2 O and Li Cl/H2 O mixtures were also used as additives, they were beneficial for solid–liquid demixing, especially when Li Cl/H2 O mixed additives were used. The membrane prepared with 5% Li Cl ＋ 2% H2 O achieved a flux of24.53 kg/（m2·hr） with 99.98% salt rejection. This study is expected to offer a reference not only for PVDF-CTFE membrane preparation but also for other polymer membranes.展开更多
[Objectives]This study was conducted to improve the ecological and economic benefits of Pinus elliottii plantations in Pengchang Forest Farm, Jingmen City. [Methods] P. elliottii plantations in Pengchang Forest Farm i...[Objectives]This study was conducted to improve the ecological and economic benefits of Pinus elliottii plantations in Pengchang Forest Farm, Jingmen City. [Methods] P. elliottii plantations in Pengchang Forest Farm in Jingmen City were selected as the research object, and the appearance and quantitative characteristics of P. elliottii community were studied and analyzed by a sampling method. [Results] Phanerophytes were the most in the P. elliottii community, accounting for 50%. In the community, except P. elliottii, the importance values of native plants were higher. The order of species diversity of P. elliottii community in Pengchang Forest Farm was herb layer, tree layer and shrub layer. The stress resistance of the community was weak, and strong intraspecific competition existed in P. elliottii. It is recommended to thin P. elliottii trees with insufficient lighting, poor growth potential and severely damaged tree body, and interplant Phoebe zhennan after thinning the P. elliottii plantations, so as to create a coniferous and broad-leaved evergreen mixed forest. [Conclusions] This study provides scientific support for thinning, tending, and forest management of P. elliottii plantations.展开更多
Ti3C2Tx has been emerging as an attractive platform to prepare composite catalysts,and their assembly into integrated catalytic mate rials repre sents a key step forward toward practical applications.Howeve r,the swel...Ti3C2Tx has been emerging as an attractive platform to prepare composite catalysts,and their assembly into integrated catalytic mate rials repre sents a key step forward toward practical applications.Howeve r,the swelling behavior of Ti3C2Tx leads to significant structure change,which challenges the stability of Ti3C2Tx-based integrated functional materials for catalytic applications.Here we report a facile synthesis of Pd/Ti3C2Tx■graphene hydrogels in which Pd/Ti3C2Tx are spatially encapsulated in the 3 D porous graphene framework.The porous interconnected structure not only affords efficient mass transfer and desirable functional accessibility to catalytic active sites,but also effectively buffers the swelling behavior of Ti3C2Tx.When applied for catalytic hydrogenation of nitroaromatic compounds,the mechanically robust Pd/Ti3C2Tx■graphene hydrogels exhibit efficient activities,easy separability,and good cyclability.This work is expected to promote the application of Ti3C2Tx-based functional materials for practical applications involving interactions with salt solutions,such as supercapacitors,catalysis,and water purification.展开更多
Small and medium-sized enterprises are the foundation of China's national economy,and they are important forces to promote economic and social development.They play an irreplaceable role in promoting scientific an...Small and medium-sized enterprises are the foundation of China's national economy,and they are important forces to promote economic and social development.They play an irreplaceable role in promoting scientific and technological progress,increasing social employment,expanding foreign trade,and other aspects in which they have become an important part of China's socialist market economy.Based on the research background of international trade financing,this paper analyzes the problems existing in the international trade fmancing of small and medium-sized enterprises in China to put forward countermeasures and suggestions,hoping to help these small and medium-sized enterprises solve the financing problem so as to achieve a healthy development in the international trade market environment.展开更多
Shuttle effect is one of the most serious disadvantages in lithium-sulfur battery which results in poor cycle performance and hinders the commercialization of Li-S battery.To reduce the dissolution of polysulfides int...Shuttle effect is one of the most serious disadvantages in lithium-sulfur battery which results in poor cycle performance and hinders the commercialization of Li-S battery.To reduce the dissolution of polysulfides into the electrolyte and prolong the cycling stability,nanoparticle-stacked metal nitride derived from layered double hydroxides(LDHs)as an interlayer was inserted between sulfur cathode and separator to confine polysulfides by physical and chemical interactions.Meanwhile,the surface of metal nitride will form an oxide passivation layer.The passivation layer possesses hydrophilic metal-O group and provides a polar surface for strong binding with polysulfide.What’s more,the nanoparticlesstacked structure could immerge and retain electrolyte well,which could enhance the ability of promoting the electron exchange rate.The sulfur electrode with nanoparticle-stacked metal nitride interlayer has an excellent cycle performance owing to the interactions between metal nitride and polysulfides.The battery delivered an initial capacity of 764.6 m Ahg^(-1) and still possesses a capacity of 477.5 mAhg^(-1) with the retention of 62.4% after 800 cycles.展开更多
Bottom-up assembly of nanostructured thin films could offer an alternative low-cost approach to elec-tronic thin films.However,such solution-processed thin films are often plagued by excessive inter-particle resistanc...Bottom-up assembly of nanostructured thin films could offer an alternative low-cost approach to elec-tronic thin films.However,such solution-processed thin films are often plagued by excessive inter-particle resistance and only exhibit limited current delivering capability.Here,we report a novel approach to fabricate highly conductive free-standing metallic thin film,accomplished by combining interfacial self-assembly of nanoparticles(NPs)and a light welding process.We found that light from a xenon lamp can weld adjacent Ag and Au NPs assembled at the water-air interface,forming a highly interconnected,free-standing metallic thin film structure with excellent electrical transport properties.With such a unique structure,the resultant thin metallic films show not only high flexibility and robustness,but also high conductivity comparable to bulk metallic thin films.Our studies offer a low-cost,room-temperature,and solution-processable approach to highly conductive metallic films.It can significantly impact solution-processable elec-tronic and optoelectronic devices.展开更多
Conventional sliding-mode observer(SMO)-based grid-voltage observation methods often require a low-pass filter(LPF)to remove high-frequency sliding-mode noise.However,a complicated phase-and amplitude-compensation met...Conventional sliding-mode observer(SMO)-based grid-voltage observation methods often require a low-pass filter(LPF)to remove high-frequency sliding-mode noise.However,a complicated phase-and amplitude-compensation method,which is highly sensitive to the DC-offset,is required.A frequency-adaptive dual second-order generalized integrator(SOGI)can be used to replace the LPF,eliminating the compensation link and the effects of the DC-offset;however,strong coupling is introduced between the front-end SOGI block and back-end phase-locked loop(PLL)block,thereby reducing the dynamic performance.To solve this problem,this study proposes an SMO-based grid-voltage observation method with a frequency-fixed dual SOGI and cross-compensated PLL that can eliminate the frequency coupling between the front-end SOGI block and back-end PLL blocks,thereby increasing its dynamic performance.In this study,the phase and amplitude are compensated simultaneously using the proposed cross-compensation method,achieving an accurate observation of the grid voltage under off-nominal frequencies.An analysis of the small-signal model theoretically verified that the proposed method has good dynamic performance.Finally,the superiority of the proposed method is verified through comparative experiments.展开更多
基金supported by the National Natural Science Foundation of China(52272295,52071137,51977071,51802040,and 21802020)the Science and Technology Innovation Program of Hunan Province(2021RC3066 and 2021RC3067)+2 种基金the Natural Science Foundation of Hunan Province(2020JJ3004 and 2020JJ4192)Graduate Research Innovation Project of Hunan Province(CX20240456 and CX20240405)N.Zhang and X.Xie also acknowledge the financial support of the Fundamental Research Funds for the Central。
文摘P2-type layered oxide Na_(2/3)Ni_(1/3)Mn_(2/3)O_(2)(NM)is a promising cathode material for sodium-ion batteries(SIBs).However,the severe irreversible phase transition,sluggish Na+diffusion kinetics,and interfacial side reactions at high-voltage result in grievous capacity degradation and inferior electrochemical performance.Herein,a dual-function strategy of entropy tuning and artificial cathode electrolyte interface(CEI)layer construction is reported to generate a novel P2-type medium-entropy Na_(0.75)Li_(0.1)Mg_(0.05)Ni_(0.18)Mn_(0.66)Ta_(0.01)O_(2)with NaTaO_(3)surface modification(LMNMT)to address the aforementioned issues.In situ X-ray diffraction reveals that LMNMT exhibits a near zero-strain phase transition with a volume change of only 1.4%,which is significantly lower than that of NM(20.9%),indicating that entropy tuning effectively suppresses irreversible phase transitions and enhances ion diffusion.Kinetic analysis and post-cycling interfacial characterization further confirm that the artificial CEI layer promotes the formation of a stable,thin NaF-rich CEI and reduces interfacial side reactions,thereby further enhancing ion transport kinetics and surface/interface stability.Consequently,the LMNMT electrode exhibits outstanding rate capability(46 mA h g^(−1)at 20 C)and cycling stability(89.5%capacity retention after 200 cycles at 2 C)within the voltage range of 2–4.35 V.The LMNMT also exhibits superior all-climate performance and air stability.This study provides a novel path for the design of high-voltage cathode materials for SIBs.
基金financially supported by the National Natural Science Foundation of China(51977071)the Natural Science Foundation of Hunan Province(2017JJ2040)the Science and Technology Innovation Program of Hunan Province(2021RC3066)。
文摘The practical application of room-temperature sodium-sulfur(RT Na-S)batteries is hindered by sluggish reaction kinetics and deleterious side reactions.To address these challenges,a defective carbon is designed as a sulfur host through a simple temperature-controlled method.The abundant porosity and surface roughness enhance sulfur encapsulation and mitigate side reactions.Prominently,highly disordered structure facilitates the chemical adsorption towards NaPSs and accelerates sulfur conversion.Furthermore,electrochemical characterizations reveal that concentration polarization during the formation of long-chain NaPSs emerges as the key polarization and activation polarization dominates the nucleation of Na_(2)S during discharge,while they both significantly affect the formation of S_(8)/long-chain NaPSs during charge.Owing to the improved adsorption capability and electrocalatytic sites,S/CZ-900presents lower concentration polarization and activation polarization during both discharge and charge.Consequently,S/CZ-900 cathode achieves 1031,914,and 671 mAh g^(-1)at 1,2,and 5 C.The cathode with a high sulfur loading of 6.4 mg cm^(-2)delivers an impressive areal capacity of 14.3 mAh cm^(-2).Moreover,the S/CZ-900||Na/CZ-900(Al)full cell exhibits robust cycling stability,maintaining 1094 mAh g^(-1)after 40 cycles at 0.1 C.The insights provide a workable solution of metal-free carbonaceous host materials for the evolution of RT Na-S batteries.
基金This work was supported by the National Natural Science Foundation of China(52071137,51977071,51802040,and 21802020)the Science and Technology Innovation Program of Hunan Province(2021RC3066 and 2021RC3067)+1 种基金the Natural Science Foundation of Hunan Province(2020JJ3004 and 2020JJ4192)N.Zhang and X.Xie also acknowledge the financial support of the Fundamental Research Funds for the Central Universities.
文摘Low-temperature assembly of MXene nanosheets into three-dimensional(3D) robust aerogels addresses the crucial stability concern of the nano-building blocks during the fabrication process,which is of key importance for transforming the fascinating properties at the nanoscale into the macroscopic scale for practical applications.Herein,suitable cross-linking agents(amino-propyltriethoxysilane,Mn^(2+),Fe^(2+),Zn^(2+),and Co^(2+)) as interfacial mediators to engineer the interlayer interactions are reported to realize the graphene oxide(GO)-assisted assembly of Ti_(3)C_(2)T_(x) MXene aerogel at room temperature.This elaborate aerogel construction not only suppresses the oxidation degradation of Ti_(3)C_(2)T_(x) but also generates porous aerogels with a high Ti_(3)C_(2)T_(x) content(87 wt%) and robustness,thereby guaranteeing the functional accessibility of Ti_(3)C_(2)T_(x) nanosheets and operational reliability as integrated functional materials.In combination with a further sulfur modification,the Ti_(3)C_(2)T_(x) aerogel electrode shows promising electrochemical performances as the freestanding anode for sodium-ion storage.Even at an ultrahigh loading mass of 12.3 mg cm^(-2),a pronounced areal capacity of 1.26 mAh cm^(-2) at a current density of 0.1 A g^(-1) has been achieved,which is of practical significance.This work conceptually suggests a new way to exert the utmost surface functionalities of MXenes in 3D monolithic form and can be an inspiring scaffold to promote the application of MXenes in different areas.
基金Financial support by the National Natural Science Foundation of China (Nos. 51378491, 51578533, 21307149) is also gratefully acknowledged
文摘Four common types of additives for polymer membrane preparation including organic macromolecule and micromolecule additives, inorganic salts and acids, and the strong non-solvent H2 O were used to prepare poly（vinylidene fluoride-co-chlorotrifluoroethylene）（PVDF-CTFE） hydrophobic flat-sheet membranes. Membrane properties including morphology, porosity, hydrophobicity, pore size and pore distribution were investigated, and the permeability was evaluated via direct contact membrane distillation（DCMD） of 3.5 g/L Na Cl solution in a DCMD configuration. Both inorganic and organic micromolecule additives were found to slightly influence membrane hydrophobicity. Polyethylene glycol（PEG）,organic acids, Li Cl, Mg Cl2, and Li Cl/H2 O mixtures were proved to be effective additives to PVDF-CTFE membranes due to their pore-controlling effects and the capacity to improve the properties and performance of the resultant membranes. The occurrence of a pre-gelation process showed that when organic and inorganic micromolecules were added to PVDF-CTFE solution, the resultant membranes presented a high interconnectivity structure. The membrane prepared with dibutyl phthalate（DBP） showed a nonporous surface and symmetrical cross-section. When H2 O and Li Cl/H2 O mixtures were also used as additives, they were beneficial for solid–liquid demixing, especially when Li Cl/H2 O mixed additives were used. The membrane prepared with 5% Li Cl ＋ 2% H2 O achieved a flux of24.53 kg/（m2·hr） with 99.98% salt rejection. This study is expected to offer a reference not only for PVDF-CTFE membrane preparation but also for other polymer membranes.
文摘[Objectives]This study was conducted to improve the ecological and economic benefits of Pinus elliottii plantations in Pengchang Forest Farm, Jingmen City. [Methods] P. elliottii plantations in Pengchang Forest Farm in Jingmen City were selected as the research object, and the appearance and quantitative characteristics of P. elliottii community were studied and analyzed by a sampling method. [Results] Phanerophytes were the most in the P. elliottii community, accounting for 50%. In the community, except P. elliottii, the importance values of native plants were higher. The order of species diversity of P. elliottii community in Pengchang Forest Farm was herb layer, tree layer and shrub layer. The stress resistance of the community was weak, and strong intraspecific competition existed in P. elliottii. It is recommended to thin P. elliottii trees with insufficient lighting, poor growth potential and severely damaged tree body, and interplant Phoebe zhennan after thinning the P. elliottii plantations, so as to create a coniferous and broad-leaved evergreen mixed forest. [Conclusions] This study provides scientific support for thinning, tending, and forest management of P. elliottii plantations.
基金support from the National Natural Science Foundation of China(Nos.51802040,51977071 and 21802020)Key Laboratory of Coal to Ethylene Glycol and Its Related Technology,Chinese Academy of Sciences(No.201901)+1 种基金Natural Science Foundation of Hunan Prvoince(No.2017JJ2040)the Fundamental Research Funds for the Central Universities。
文摘Ti3C2Tx has been emerging as an attractive platform to prepare composite catalysts,and their assembly into integrated catalytic mate rials repre sents a key step forward toward practical applications.Howeve r,the swelling behavior of Ti3C2Tx leads to significant structure change,which challenges the stability of Ti3C2Tx-based integrated functional materials for catalytic applications.Here we report a facile synthesis of Pd/Ti3C2Tx■graphene hydrogels in which Pd/Ti3C2Tx are spatially encapsulated in the 3 D porous graphene framework.The porous interconnected structure not only affords efficient mass transfer and desirable functional accessibility to catalytic active sites,but also effectively buffers the swelling behavior of Ti3C2Tx.When applied for catalytic hydrogenation of nitroaromatic compounds,the mechanically robust Pd/Ti3C2Tx■graphene hydrogels exhibit efficient activities,easy separability,and good cyclability.This work is expected to promote the application of Ti3C2Tx-based functional materials for practical applications involving interactions with salt solutions,such as supercapacitors,catalysis,and water purification.
文摘Small and medium-sized enterprises are the foundation of China's national economy,and they are important forces to promote economic and social development.They play an irreplaceable role in promoting scientific and technological progress,increasing social employment,expanding foreign trade,and other aspects in which they have become an important part of China's socialist market economy.Based on the research background of international trade financing,this paper analyzes the problems existing in the international trade fmancing of small and medium-sized enterprises in China to put forward countermeasures and suggestions,hoping to help these small and medium-sized enterprises solve the financing problem so as to achieve a healthy development in the international trade market environment.
基金supported by the National Natural Science Foundation of China(21701043,51402100,50702020,21573066 and 81171461)the Provincial Natural Science Foundation of Hunan(2016JJ1006,2016TP1009 and 11JJ4013)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province
文摘Shuttle effect is one of the most serious disadvantages in lithium-sulfur battery which results in poor cycle performance and hinders the commercialization of Li-S battery.To reduce the dissolution of polysulfides into the electrolyte and prolong the cycling stability,nanoparticle-stacked metal nitride derived from layered double hydroxides(LDHs)as an interlayer was inserted between sulfur cathode and separator to confine polysulfides by physical and chemical interactions.Meanwhile,the surface of metal nitride will form an oxide passivation layer.The passivation layer possesses hydrophilic metal-O group and provides a polar surface for strong binding with polysulfide.What’s more,the nanoparticlesstacked structure could immerge and retain electrolyte well,which could enhance the ability of promoting the electron exchange rate.The sulfur electrode with nanoparticle-stacked metal nitride interlayer has an excellent cycle performance owing to the interactions between metal nitride and polysulfides.The battery delivered an initial capacity of 764.6 m Ahg^(-1) and still possesses a capacity of 477.5 mAhg^(-1) with the retention of 62.4% after 800 cycles.
基金supported by the National Natural Science Foundation of China(21673070 and 61528403)the Opened Fund of the Chinese State Key Laboratory on Integrated Optoelectronics(IOSKL2015KF29)Hunan University
文摘Bottom-up assembly of nanostructured thin films could offer an alternative low-cost approach to elec-tronic thin films.However,such solution-processed thin films are often plagued by excessive inter-particle resistance and only exhibit limited current delivering capability.Here,we report a novel approach to fabricate highly conductive free-standing metallic thin film,accomplished by combining interfacial self-assembly of nanoparticles(NPs)and a light welding process.We found that light from a xenon lamp can weld adjacent Ag and Au NPs assembled at the water-air interface,forming a highly interconnected,free-standing metallic thin film structure with excellent electrical transport properties.With such a unique structure,the resultant thin metallic films show not only high flexibility and robustness,but also high conductivity comparable to bulk metallic thin films.Our studies offer a low-cost,room-temperature,and solution-processable approach to highly conductive metallic films.It can significantly impact solution-processable elec-tronic and optoelectronic devices.
基金Supported by the Outstanding Youth Science Foundation of Henan Province(242300421074)Henan Province Key R&D Project(241111210400,241111242300).
文摘Conventional sliding-mode observer(SMO)-based grid-voltage observation methods often require a low-pass filter(LPF)to remove high-frequency sliding-mode noise.However,a complicated phase-and amplitude-compensation method,which is highly sensitive to the DC-offset,is required.A frequency-adaptive dual second-order generalized integrator(SOGI)can be used to replace the LPF,eliminating the compensation link and the effects of the DC-offset;however,strong coupling is introduced between the front-end SOGI block and back-end phase-locked loop(PLL)block,thereby reducing the dynamic performance.To solve this problem,this study proposes an SMO-based grid-voltage observation method with a frequency-fixed dual SOGI and cross-compensated PLL that can eliminate the frequency coupling between the front-end SOGI block and back-end PLL blocks,thereby increasing its dynamic performance.In this study,the phase and amplitude are compensated simultaneously using the proposed cross-compensation method,achieving an accurate observation of the grid voltage under off-nominal frequencies.An analysis of the small-signal model theoretically verified that the proposed method has good dynamic performance.Finally,the superiority of the proposed method is verified through comparative experiments.
