As a companion paper to Zhou RX et al.(2020),this study describes application of the automatic detection and analysis module to identify all the tweek atmospherics detectible in the WHU ELF/VLF receiver data collected...As a companion paper to Zhou RX et al.(2020),this study describes application of the automatic detection and analysis module to identify all the tweek atmospherics detectible in the WHU ELF/VLF receiver data collected at Suizhou station during the period of 3 February through 29 February 2016.Detailed analysis of the identified low-latitude tweek events reveals that the occurrence rate varies considerably—from 800 to 6000 tweeks per day,and exhibits a strong diurnal and local time dependence,the peak occurring before local midnight.The diurnal variation of identified tweeks was similar to that of the lightning data obtained by the World-Wide Lightning Location Network(WWLLN)..Estimates of the propagation distance and ionospheric reflection height of tweek atmospherics suggest that the majority(~92%)of the low latitude tweeks originate from the lightning activity within a radius of 4000 km and that they are very likely to reflect from the lower ionospheric D-region at the height range of 75–85 km.At these lower ionospheric reflection altitudes,~74%of the corresponding electron densities from the tweek spectral measurements are within 24.5–27.5 cm^-3.The daily variation of estimated D-region electron densities in the considered period(February 2016)also exhibits a small overall increasing trend from early to later in the month.展开更多
This paper investigates the finite-time H_(∞)control problem for a class of nonlinear discrete-time one-sided Lipschitz systems with uncertainties.Using the one-sided Lipschitz and quadratically inner-bounded conditi...This paper investigates the finite-time H_(∞)control problem for a class of nonlinear discrete-time one-sided Lipschitz systems with uncertainties.Using the one-sided Lipschitz and quadratically inner-bounded conditions,the authors derive less conservative criterion for the controller design and observer design.A new criterion is proposed to ensure the closed-loop system is finite-time bounded(FTB).The sufficient conditions are established to ensure the closed-loop system is H_(∞)finite-time bounded(H_(∞)FTB)in terms of matrix inequalities.The controller gains and observer gains are given.A numerical example is provided to demonstrate the effectiveness of the proposed results.展开更多
Designing advanced and cost-effective electrocatalytic system for nitric oxide(NO)reduction reaction(NORR)is vital for sustainable NH_(3) production and NO removal,yet it is a challenging task.Herein,it is shown that ...Designing advanced and cost-effective electrocatalytic system for nitric oxide(NO)reduction reaction(NORR)is vital for sustainable NH_(3) production and NO removal,yet it is a challenging task.Herein,it is shown that phosphorus(P)-doped titania(TiO_(2))nanotubes can be adopted as highly efficient catalyst for NORR.The catalyst demonstrates impressive performance in ionic liquid(IL)-based electrolyte with a remarkable high Faradaic efficiency of 89%and NH3 yield rate of 425μg·h^(−1)·mg_(cat).^(−1),being close to the best-reported results.Noteworthy,the obtained performance metrics are significantly larger than those for N_(2) reduction reaction.It also shows good durability with negligible activity decay even after 10 cycles.Theoretical simulations reveal that the introduction of P dopants tunes the electronic structure of Ti active sites,thereby enhancing the NO adsorption and facilitating the desorption of ^(*)NH_(3).Moreover,the utilization of IL further suppresses the competitive hydrogen evolution reaction.This study highlights the advantage of the catalyst−electrolyte engineering strategy for producing NH_(3) at a high efficiency and rate.展开更多
Highly efficient Co_(3)O_(4)/TiO_(2) monolithic catalysts with enhanced stability were in-situ grown on Ti mesh for CO oxidation,which could completely oxidize CO at 120℃.The comprehensive catalytic performance is co...Highly efficient Co_(3)O_(4)/TiO_(2) monolithic catalysts with enhanced stability were in-situ grown on Ti mesh for CO oxidation,which could completely oxidize CO at 120℃.The comprehensive catalytic performance is competitive to some noble metal catalysts and conventional Co_(3)O_(4) powder catalysts,which holds great potential toward industrial applications.Meanwhile,the in-situ synthesis strategy of Co_(3)O_(4)/TiO_(2) monolithic catalysts on flexible mesh substrate in this work can be extended to the development of a variety of oxide-based monolithic catalysts towards diverse catalysis applications.展开更多
In this study, we reported the in-situ fabrication of a series of Fe_(2)O_(3)/TiO_(2) monolithic catalysts on flexible Ti mesh via plasma electrolytic oxidation process, hydrothermal reaction and chemical bath deposit...In this study, we reported the in-situ fabrication of a series of Fe_(2)O_(3)/TiO_(2) monolithic catalysts on flexible Ti mesh via plasma electrolytic oxidation process, hydrothermal reaction and chemical bath deposition(CBD) method. The morphology tailoring of Fe_(2)O_(3) nanostructures finds that Fe2O3 nanosheets supported on TiO2 exhibit superior catalytic performance with a complete oxidation of CO at 260℃. The catalytic stability test indicates that the in-situ grown Fe_(2)O_(3)/TiO_(2) catalysts own outstanding performance for continuous CO oxidation due to the strong substrate adhesion without mass loss. The microstructures and interfaces of Fe_(2)O_(3)/TiO_(2) catalysts are well studied using series of characterization techniques. The in-situ preparation strategy of metal oxide catalysts in this work will open up more opportunities for the rational design of variety of monolithic catalysts used for CO oxidation, de-NO_(x), three-way catalysis and other related application in industry.展开更多
The stacking structure of Nb_(2)CSe_(2),a newly synthesized layered metal carbo-selenide,was elucidated by scanning transmission electron microscopy.Nb,CSe2 features Se-Nb-C-Nb-Se quintuple atomic layers.These layers ...The stacking structure of Nb_(2)CSe_(2),a newly synthesized layered metal carbo-selenide,was elucidated by scanning transmission electron microscopy.Nb,CSe2 features Se-Nb-C-Nb-Se quintuple atomic layers.These layers are stacked in Bernal mode.In this mode,Nb,CSe2 crystallizes in a trigonal symmetry(space group P3m1,No.164),with lattice parameters of a=3.33 A and c=18.20 A.Electronic structure calculations indicate that the metal carbo-selenide has Fermi energy crossing the bands where it touches to give a zero gap,indicating that it is an electronic conductor.As evidenced experimentally,the electrical conductivity is as high as 6.6×10^(5) S·m^(-1),outperforming the counterparts in the MXene family.Owing to the layered structure,the bonding in Nb_(2)CSe_(2) with an ionic formula of(Nb^(1.48+)),(C^(1.74-))(Se^(0.61-))_(2) is highly anisotropic,with metallic-covalent-ionic bonding in intralayers and weak bonding between interlayers.The layered nature is further evidenced by elastic properties,interlayer energy,and friction coefficient determination.These characteristics indicate that Nb_(2)CSe_(2) is an analog of molybdenum disulfide(MoS_(2)),which is a typical binary van der Waals(vdW)solid.Moreover,vibrational properties are reported,which may offer an optical identification standardfor new ternary vdW solids in spectroscopic studies,including Raman scatteringand infrared absorption.展开更多
基金supported by the National Natural Science Foundation of China (Grants Nos. 41674163, 41474141, 41204120,41304127, 41304130, and 41574160)the Projects funded by China Postdoctoral Science Foundation (Grants Nos. 2013M542051, 2014T70732)+2 种基金the Hubei Province Natural Science Excellent Youth Foundation (2016CFA044)The project Supported by the Specialized Research Fund for State Key Laboratoriesthe 985 funded project of School of Electronic information, Wuhan University。
文摘As a companion paper to Zhou RX et al.(2020),this study describes application of the automatic detection and analysis module to identify all the tweek atmospherics detectible in the WHU ELF/VLF receiver data collected at Suizhou station during the period of 3 February through 29 February 2016.Detailed analysis of the identified low-latitude tweek events reveals that the occurrence rate varies considerably—from 800 to 6000 tweeks per day,and exhibits a strong diurnal and local time dependence,the peak occurring before local midnight.The diurnal variation of identified tweeks was similar to that of the lightning data obtained by the World-Wide Lightning Location Network(WWLLN)..Estimates of the propagation distance and ionospheric reflection height of tweek atmospherics suggest that the majority(~92%)of the low latitude tweeks originate from the lightning activity within a radius of 4000 km and that they are very likely to reflect from the lower ionospheric D-region at the height range of 75–85 km.At these lower ionospheric reflection altitudes,~74%of the corresponding electron densities from the tweek spectral measurements are within 24.5–27.5 cm^-3.The daily variation of estimated D-region electron densities in the considered period(February 2016)also exhibits a small overall increasing trend from early to later in the month.
基金supported by the Natural Science Foundation of Tianjin under Grant No.18JCYBJC88000.
文摘This paper investigates the finite-time H_(∞)control problem for a class of nonlinear discrete-time one-sided Lipschitz systems with uncertainties.Using the one-sided Lipschitz and quadratically inner-bounded conditions,the authors derive less conservative criterion for the controller design and observer design.A new criterion is proposed to ensure the closed-loop system is finite-time bounded(FTB).The sufficient conditions are established to ensure the closed-loop system is H_(∞)finite-time bounded(H_(∞)FTB)in terms of matrix inequalities.The controller gains and observer gains are given.A numerical example is provided to demonstrate the effectiveness of the proposed results.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.22075211,21601136,and 21905246)the Key Projects of Zhejiang Natural Science Foundation(Grant No.LZ20E010001).
文摘Designing advanced and cost-effective electrocatalytic system for nitric oxide(NO)reduction reaction(NORR)is vital for sustainable NH_(3) production and NO removal,yet it is a challenging task.Herein,it is shown that phosphorus(P)-doped titania(TiO_(2))nanotubes can be adopted as highly efficient catalyst for NORR.The catalyst demonstrates impressive performance in ionic liquid(IL)-based electrolyte with a remarkable high Faradaic efficiency of 89%and NH3 yield rate of 425μg·h^(−1)·mg_(cat).^(−1),being close to the best-reported results.Noteworthy,the obtained performance metrics are significantly larger than those for N_(2) reduction reaction.It also shows good durability with negligible activity decay even after 10 cycles.Theoretical simulations reveal that the introduction of P dopants tunes the electronic structure of Ti active sites,thereby enhancing the NO adsorption and facilitating the desorption of ^(*)NH_(3).Moreover,the utilization of IL further suppresses the competitive hydrogen evolution reaction.This study highlights the advantage of the catalyst−electrolyte engineering strategy for producing NH_(3) at a high efficiency and rate.
基金partially supported by the National Natural Science Foundation of China(No.51872296)the Joint Fund between Shenyang National Laboratory for Materials Science and State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals(No.18LHPY012)。
文摘Highly efficient Co_(3)O_(4)/TiO_(2) monolithic catalysts with enhanced stability were in-situ grown on Ti mesh for CO oxidation,which could completely oxidize CO at 120℃.The comprehensive catalytic performance is competitive to some noble metal catalysts and conventional Co_(3)O_(4) powder catalysts,which holds great potential toward industrial applications.Meanwhile,the in-situ synthesis strategy of Co_(3)O_(4)/TiO_(2) monolithic catalysts on flexible mesh substrate in this work can be extended to the development of a variety of oxide-based monolithic catalysts towards diverse catalysis applications.
基金the National Natural Science Foundation of China(No.51702326,51872296)the Joint Fund between Shenyang National Laboratory for Materials Science and State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals(Grant No.18LHPY012)。
文摘In this study, we reported the in-situ fabrication of a series of Fe_(2)O_(3)/TiO_(2) monolithic catalysts on flexible Ti mesh via plasma electrolytic oxidation process, hydrothermal reaction and chemical bath deposition(CBD) method. The morphology tailoring of Fe_(2)O_(3) nanostructures finds that Fe2O3 nanosheets supported on TiO2 exhibit superior catalytic performance with a complete oxidation of CO at 260℃. The catalytic stability test indicates that the in-situ grown Fe_(2)O_(3)/TiO_(2) catalysts own outstanding performance for continuous CO oxidation due to the strong substrate adhesion without mass loss. The microstructures and interfaces of Fe_(2)O_(3)/TiO_(2) catalysts are well studied using series of characterization techniques. The in-situ preparation strategy of metal oxide catalysts in this work will open up more opportunities for the rational design of variety of monolithic catalysts used for CO oxidation, de-NO_(x), three-way catalysis and other related application in industry.
基金supported by the Shenyang National Laboratory for Materials Science,Institute of Metal Research,Chinese Academy of Sciences,Basic and Applied Basic Research Program of Guangdong Province(No.2021B0301030003)Ji Hua Laboratory(No.X210141TL210)。
文摘The stacking structure of Nb_(2)CSe_(2),a newly synthesized layered metal carbo-selenide,was elucidated by scanning transmission electron microscopy.Nb,CSe2 features Se-Nb-C-Nb-Se quintuple atomic layers.These layers are stacked in Bernal mode.In this mode,Nb,CSe2 crystallizes in a trigonal symmetry(space group P3m1,No.164),with lattice parameters of a=3.33 A and c=18.20 A.Electronic structure calculations indicate that the metal carbo-selenide has Fermi energy crossing the bands where it touches to give a zero gap,indicating that it is an electronic conductor.As evidenced experimentally,the electrical conductivity is as high as 6.6×10^(5) S·m^(-1),outperforming the counterparts in the MXene family.Owing to the layered structure,the bonding in Nb_(2)CSe_(2) with an ionic formula of(Nb^(1.48+)),(C^(1.74-))(Se^(0.61-))_(2) is highly anisotropic,with metallic-covalent-ionic bonding in intralayers and weak bonding between interlayers.The layered nature is further evidenced by elastic properties,interlayer energy,and friction coefficient determination.These characteristics indicate that Nb_(2)CSe_(2) is an analog of molybdenum disulfide(MoS_(2)),which is a typical binary van der Waals(vdW)solid.Moreover,vibrational properties are reported,which may offer an optical identification standardfor new ternary vdW solids in spectroscopic studies,including Raman scatteringand infrared absorption.
