Efficient recognition and selective capture of NH_(3)is not only beneficial for increasing the productivity of the synthetic NH_(3)industry but also for reducing air pollution.For this purpose,a group of deep eutectic...Efficient recognition and selective capture of NH_(3)is not only beneficial for increasing the productivity of the synthetic NH_(3)industry but also for reducing air pollution.For this purpose,a group of deep eutectic solvents(DESs)consisting of glycolic acid(GA)and phenol(PhOH)with low viscosities and multiple active sites was rationally designed in this work.Experimental results show that the GA^(+)PhOH DESs display extremely fast NH_(3)absorption rates(within 51 s for equilibrium)and high NH_(3)solubility.At 313.2 K,the NH_(3)absorption capacities of GA^(+)PhOH(1:1)reach 6.75 mol/kg(at 10.7 kPa)and 14.72 mol/kg(at 201.0 kPa).The NH_(3)solubility of GA^(+)PhOH DESs at low pressures were minimally changed after more than 100 days of air exposure.In addition,the NH_(3)solubility of GA^(+)PhOH DESs remain highly stable in 10 consecutive absorption-desorption cycles.More importantly,NH_(3)can be selectively captured by GA^(+)PhOH DESs from NH_(3)/CO_(2)/N_(2)and NH_(3)/N_(2)/H_(2)mixtures.1H-NMR,Fourier transform infrared and theoretical calculations were performed to reveal the intrinsic mechanism for the efficient recognition of NH_(3)by GA^(+)PhOH DESs.展开更多
The efficient separation and collection of ammonia(NH_(3))during NH_(3) synthesis process is essential to improve the economic efficiency and protect the environment.In this work,ethanolammonium hydrochloride(EtOHACl)...The efficient separation and collection of ammonia(NH_(3))during NH_(3) synthesis process is essential to improve the economic efficiency and protect the environment.In this work,ethanolammonium hydrochloride(EtOHACl)and phenol(PhOH)were used to prepare a novel class of deep eutectic solvents(DESs)with multiple active sites and low viscosities.The NH_(3) separation performance of EtOHACl+PhOH DESs was analyzed completely.It is figured out that the NH_(3) absorption rates in EtOHACl+PhOH DESs are very fast.The NH_(3) absorption capacities are very high and reach up to 5.52 and 10.74 mol·kg1 at 11.2 and 100.4 kPa under 298.2 K,respectively.In addition,the EtOHACl+PhOH DESs present highly selective absorption of NH_(3) over N_(2) and H_(2) and good regenerative properties after seven cycles of absorption/desorption.The intrinsic separation mechanism of NH_(3) by EtOHACl+PhOH DESs was further revealed by spectroscopic analysis and quantum chemistry calculations.展开更多
The development of highly active and stable bifunctional electrocatalysts in acidic media is crucial to hydrogen production by proton exchange membrane.In this study,we designed a RuO_(2)-IrO_(2)heterostructure cataly...The development of highly active and stable bifunctional electrocatalysts in acidic media is crucial to hydrogen production by proton exchange membrane.In this study,we designed a RuO_(2)-IrO_(2)heterostructure catalyst coupled by carbon quantum dots(CQDs).The catalyst showed excellent electrocatalytic performance for water splitting under acidic conditions.The overpotentials of oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)were as low as 180 and 15 mV at 10 mA/cm^(2)in 0.5 M H_(2)SO_(4),respectively.The acid electrolytic cell developed with RuO_(2)-IrO_(2)@CQDs as anode and cathode operated stably at 10 m A/cm^(2)for 120 h.In situ measurements and theoretical calculation reveal that the unique lattice oxygen mechanism path of RuO_(2)-IrO_(2)@CQDs can bypass the OOH^(*)intermediate and breaks the linear relationship of adsorbent evolution mechanism path,resulting in higher OER catalytic activity.展开更多
Active multiple tuned mass dampers （referred to as AMTMD）, which consist of several active tuned mass dampers （ATMDs） with identical stiffness and damping coefficients but varying mass and control force, have rece...Active multiple tuned mass dampers （referred to as AMTMD）, which consist of several active tuned mass dampers （ATMDs） with identical stiffness and damping coefficients but varying mass and control force, have recently been proposed to suppress undesirable oscillations of structures under ground acceleration. It has been shown that the AMTMD can remarkably improve the performance of multiple tuned mass dampers （MTMDs） and is also more effective in reducing structure oscillation than single ATMDs. Notwithstanding this, good performance of AMTMD （including a single ATMD illustrated from frequency-domain analysis） may not necessarily translate into a good seismic reduction behavior in the time-domain. To investigate these phenomena, a three-story steel structure model controlled by AMTMD with three ATMDs was implemented in SIMULINK and subjected to several historical earthquakes. Likewise, the structure under consideration was assumed to have uncertainty of stiffness, such as 4-15% of its initial stiffness, in the numerical simulations. The optimum design parameters of the AMTMD were obtained in the frequency-domain by implementing the minimization of the minimum values of the maximum dynamic magnification factors （DMF） of general structures with AMTMD. For comparison purposes, response analysis of the same structure with a single ATMD was also performed. The numerical analysis and comparison show that the AMTMD generally renders better effectiveness when compared with a single ATMD for structures subjected to historical earthquakes. In particular, the AMTMD can improve the effectiveness of a single ATMD for a structure with an uncertainty of stiffness of 4-15% of its initial stiffness.展开更多
The wavelet transform method for high-quality time-frequency analysis is applied to sets of observations of relative sunspot numbers and stellar chromosphere fluxes of 10 Sun-like stars. Wavelet analysis of solar data...The wavelet transform method for high-quality time-frequency analysis is applied to sets of observations of relative sunspot numbers and stellar chromosphere fluxes of 10 Sun-like stars. Wavelet analysis of solar data shows that in a certain interval of time there are several cycles of activity with pe- riods of duration which vary considerably from each other： from quasi-biennial cycles to lO0-yr cycles. Cyclic activity was detected in almost all Sun-like stars that we examined, even those that previously were not considered as stars with cyclic activity according to analysis using a Scargle periodogram. The durations of solar and stellar cycles significantly change during the observation period.展开更多
The 1.3-dipolar cycloaddition reaction of 2-trifluoromethyl- oxazolone and the activated carbon-carbon multiple bond was studied and gave a convenient way to synthesize 2-trifluoromethylpyrrole derivatives.
The electrochemical reaction rate strongly depends on the pH of the solution and the relatively sluggish alkaline hydrogen evolution reaction(HER)process,attributed to alterations in the type of proton donor and bindi...The electrochemical reaction rate strongly depends on the pH of the solution and the relatively sluggish alkaline hydrogen evolution reaction(HER)process,attributed to alterations in the type of proton donor and binding energy,has consistently presented a significant challenge.Here,we report a new method for boosting alkaline HER via spontaneous built-in electric field strategy employed on cobalt phosphide nanofibers(NFs)electrocatalyst.The anion-cation dual-introduction of V and N on the NFs not only increases the electrochemical surface area but also enhances the catalytic activity,thereby elevating the performance of alkaline HER.An investigation strategy combining experiments and calculations revealed the charge transfer law between multiple active components and the enhanced regulation mechanism of alkaline HER process,ultimately achieving a nearly twice increase in reaction overpotential of the as-fabricated catalyst at-10 mA·cm^(-2).This new approach provides a potential strategy for improving the efficiency of core catalyst for energy conversion technologies.展开更多
Electrocatalytic synthesis of urea through C-N bond formation,converting carbon dioxide(CO_(2))and ni-trate(NO_(3)^(-)),presents a promising,less energy-intensive alternative to industrial urea production process.In t...Electrocatalytic synthesis of urea through C-N bond formation,converting carbon dioxide(CO_(2))and ni-trate(NO_(3)^(-)),presents a promising,less energy-intensive alternative to industrial urea production process.In this communication,we report the application of Mo_(2)C nanosheets-decorated carbon sheets(Mo_(2)C/C)as a highly efficient electrocatalyst for facilitating C-N coupling in ambient urea electrosynthesis.In CO_(2)-saturated 0.2 mol/L Na_(2)SO_(4)solution containing 0.05 mol/L NO_(3)^(-),the Mo_(2)C/C catalyst achieves an impres-sive urea yield of 579.13μg h^(-1)mg^(-1)with high Faradaic efficiency of 44.80%at-0.5 V versus the reversible hydrogen electrode.Further theoretical calculations reveal that the multiple Mo active sites enhance the formation of^(∗)CO and^(∗)NH_(2)intermediates and facilitate their C-N coupling.This research propels the use of Mo_(2)C-based electrodes in electrocatalysis and accentuates the capabilities of binary metal-based catalysts in C-N coupling reactions.展开更多
Developing chiral thermally activated delayed fluorescence(TADF)materials with excellent photophysical and chiroptical properties is crucial for advancing circularly polarized organic light-emitting diodes(CP-OLED).To...Developing chiral thermally activated delayed fluorescence(TADF)materials with excellent photophysical and chiroptical properties is crucial for advancing circularly polarized organic light-emitting diodes(CP-OLED).To overcome the inherent trade-off relationship between photoluminescent quantum yield(PLQY)and dissymmetry factor(g),a fixed degenerate exciton chirality(FD-EC)strategy based on the multiple resonance TADF chromophore is proposed,exhibiting improved deep-blue emission with the peak at 454 nm and a high PLQY of 0.96,and unique exciton chirality with amplified|gabs|and|gPL|values of 1.0×10^(-3) and 1.6×10^(-3).The CP-OLED,incorporating the chiral blue emitter,exhibits standard blue emission with a narrow full width at half maximum of 30 nm,a superior external quantum efficiency of 27.8%,Commission Internationale de L'Eclairage coordinates of(0.14,0.08),and distinct circularly polarized electroluminescence.展开更多
A new hybrid control scheme is presented with a robust multiple model fusion control（RMMFC） law for a UH-60 helicopter and an active disturbance rejection control（ADRC） controller for its engines.This scheme is a ...A new hybrid control scheme is presented with a robust multiple model fusion control（RMMFC） law for a UH-60 helicopter and an active disturbance rejection control（ADRC） controller for its engines.This scheme is a control design method with every subsystem designed separately but fully considering the couplings between them.With three subspaces with respect to forward flight velocity,a RMMFC is proposed to devise a four-loop reference signal tracing control for the helicopter,which escapes the closed-loop system from unstable state due to the extreme complexity of this integrated nonlinear system.The engines are controlled by the proposed ADRC decoupling controller,which fully takes advantage of a good compensation ability for unmodeled dynamics and extra disturbances,so as to compensate torque disturbance in power turbine speed loop.By simulating a forward acceleration flight task,the RMMFC for the helicopter is validated.It is apparent that the integrated helicopter and engine system（IHES） has much better dynamic performance under the new control scheme.Especially in the switching process,the large transient is significantly weakened,and smooth transition among candidate controllers is achieved.Over the entire simulation task,the droop of power turbine speed with the proposed ADRC controller is significantly slighter than with the conventional PID controller,and the response time of the former is much faster than the latter.By simulating a rapid climb and descent flight task,the results also show the feasibility for the application of the proposed multiple model fusion control.Although there is aggressive power demand in this maneuver,the droop of power turbine speed with an ADRC controller is smaller than using a PID controller.The control performance for helicopter and engine is enhanced by adopting this hybrid control scheme,and simulation results in other envelope state give proofs of robustness for this new scheme.展开更多
Interleukin 6(IL-6) is known as hybridoma cell growth factor,B-cell differentiating factor and so on One of its important biological functions in to induce
Chiral luminescence materials have potential applications in the field of three-dimensional displays due to their circularly polarized luminescence(CPL)characteristics.However,the further development of circularly pol...Chiral luminescence materials have potential applications in the field of three-dimensional displays due to their circularly polarized luminescence(CPL)characteristics.However,the further development of circularly polarized organic light-emitting diodes(CP-OLEDs)needs to meet the requirements of high efficiency,high color purity,low cost,and high dissymmetry factor(gPLor gEL),chiral multiple resonance thermally activated delayed fluorescence(MR-TADF)materials are considered as candidates in these aspects.Herein,based on a pair of chiral spirofluorene precursors,two pairs of high-performance chiral MR-TADF emitters((R/S)-p-Spiro-DtBuCzB and(R/S)-m-Spiro-DtBuCzB)are developed,which exhibit strong emissions peaking at 491 and 502 nm in toluene with full-width at half-maximum values of 25 and 33 nm,respectively.In addition,small singlet–triplet energy gaps of 0.15 and 0.10 eV with high absolute photoluminescence efficiencies of 95.0%and 96.7%are observed for p-Spiro-DtBuCzB and m-Spiro-DtBuCzB molecules,respectively.OLEDs based on p-Spiro-DtBuCzB and m-Spiro-DtBuCzB display high maximum external quantum efficiencies of 29.6%and 33.8%,respectively.Most importantly,CP-OLEDs present symmetric circularly polarized electroluminescence spectra with|gEL|factors of 3.36×10^(-4)and 7.66×10^(-4)for devices based on(R/S)-p-Spiro-DtBuCzB and(R/S)-m-Spiro-DtBuCzB enantiomers,respectively.展开更多
At present,excessive carbon dioxide(CO_(2))emission has become an increasingly prominent global energy and environmental issue.Therefore,effective methods to convert CO_(2) into fine chemicals are urgently required.He...At present,excessive carbon dioxide(CO_(2))emission has become an increasingly prominent global energy and environmental issue.Therefore,effective methods to convert CO_(2) into fine chemicals are urgently required.Herein,series of S-doped carbon-nitrogen(CNS-X)materials(where X denotes the ratio of thiourea and melamine substances ranging from 0.03 to 0.8)was prepared via the programmed temperature pyrolysis method,which thiourea(CH4N_(2)S)and melamine was used as the precursor of the catalysts.The sulfur source endow the CNS-X acidic sites,which cooperate synergistically with amino groups from the incomplete polymerization of melamine,leading to a bifunctional catalyst for cycloaddition reaction of CO_(2) with epoxides.These catalysts were characterized using X-ray diffraction,Fourier transform infrared spectroscopy,elemental analysis,X-ray photoelectron spectroscopy,and N_(2) adsorption-desorption techniques,confirming the successful integration of functional groups.The optimal thiourea doping concentration of 0.4 was certainly found to have considerably facilitated the efficient conversion of CO_(2) by the CNS-0.4 catalyst,in which the conversion of epichlorohydrin(ECH)could achieve over 90.0% and the selectivity of cyclic carbonate is 98.0% under 1.0 MPa at 140℃ for 10 h.The superior catalytic performance of CNS-0.4 was attributable to the synergistic effect arising from the co-existence of Lewis acidic and basic sites.Notably,using CNS-0.4 resulted in a high yield even after four reaction cycles.展开更多
The coexistence of multi-component active sites like single-atom sites,diatomic sites(DAS)and nanoclusters is shown to result in superior performances in the hydrogen evolution reaction(HER).Metal diatomic sites are m...The coexistence of multi-component active sites like single-atom sites,diatomic sites(DAS)and nanoclusters is shown to result in superior performances in the hydrogen evolution reaction(HER).Metal diatomic sites are more complex than single-atom sites but their unique electronic structures can lead to significant enhancement of the HER kinetics.Although the synthesis and identification of DAS is usually challenging,we report a simple access to a diatomic catalyst by anchoring Co-Ru DAS on nitrogen-doped carbon supports along with Ru nanoparticles(NPs).Experimental and theoretical results revealed the atomic-level characteristics of Co-Ru sites,their strong electronic coupling and their synergy with Ru NPs within the catalyst.The unique electronic structure of the catalyst resulted in an excellent HER activity and stability in alkaline media.This work provides a valuable insight into a widely applicable design of diatomic catalysts with multi-component active sites for highly efficient HER electrocatalysis.展开更多
基金supported by the National Natural Science Foundation of China(22008033)the Major Program of Qingyuan Innovation Laboratory.
文摘Efficient recognition and selective capture of NH_(3)is not only beneficial for increasing the productivity of the synthetic NH_(3)industry but also for reducing air pollution.For this purpose,a group of deep eutectic solvents(DESs)consisting of glycolic acid(GA)and phenol(PhOH)with low viscosities and multiple active sites was rationally designed in this work.Experimental results show that the GA^(+)PhOH DESs display extremely fast NH_(3)absorption rates(within 51 s for equilibrium)and high NH_(3)solubility.At 313.2 K,the NH_(3)absorption capacities of GA^(+)PhOH(1:1)reach 6.75 mol/kg(at 10.7 kPa)and 14.72 mol/kg(at 201.0 kPa).The NH_(3)solubility of GA^(+)PhOH DESs at low pressures were minimally changed after more than 100 days of air exposure.In addition,the NH_(3)solubility of GA^(+)PhOH DESs remain highly stable in 10 consecutive absorption-desorption cycles.More importantly,NH_(3)can be selectively captured by GA^(+)PhOH DESs from NH_(3)/CO_(2)/N_(2)and NH_(3)/N_(2)/H_(2)mixtures.1H-NMR,Fourier transform infrared and theoretical calculations were performed to reveal the intrinsic mechanism for the efficient recognition of NH_(3)by GA^(+)PhOH DESs.
基金supported by the National Natural Science Foundation of China(22221005 and 22008033).
文摘The efficient separation and collection of ammonia(NH_(3))during NH_(3) synthesis process is essential to improve the economic efficiency and protect the environment.In this work,ethanolammonium hydrochloride(EtOHACl)and phenol(PhOH)were used to prepare a novel class of deep eutectic solvents(DESs)with multiple active sites and low viscosities.The NH_(3) separation performance of EtOHACl+PhOH DESs was analyzed completely.It is figured out that the NH_(3) absorption rates in EtOHACl+PhOH DESs are very fast.The NH_(3) absorption capacities are very high and reach up to 5.52 and 10.74 mol·kg1 at 11.2 and 100.4 kPa under 298.2 K,respectively.In addition,the EtOHACl+PhOH DESs present highly selective absorption of NH_(3) over N_(2) and H_(2) and good regenerative properties after seven cycles of absorption/desorption.The intrinsic separation mechanism of NH_(3) by EtOHACl+PhOH DESs was further revealed by spectroscopic analysis and quantum chemistry calculations.
基金supported by the Natural Science Foundation of Shandong Province ZR2024MB087the National Natural Science Foundation of China(No.52122308,51973200,52202050,and 21905253)+3 种基金the Natural Science Foundation of Henan(202300410372)the Joint Fund of Science and Technology R&D Plan of Henan Province(232301420042)the China Postdoctoral Science Foundation(2022TQ0286)the Center for Modern Analysis and Gene Sequencing of Zhengzhou University for supporting this project。
文摘The development of highly active and stable bifunctional electrocatalysts in acidic media is crucial to hydrogen production by proton exchange membrane.In this study,we designed a RuO_(2)-IrO_(2)heterostructure catalyst coupled by carbon quantum dots(CQDs).The catalyst showed excellent electrocatalytic performance for water splitting under acidic conditions.The overpotentials of oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)were as low as 180 and 15 mV at 10 mA/cm^(2)in 0.5 M H_(2)SO_(4),respectively.The acid electrolytic cell developed with RuO_(2)-IrO_(2)@CQDs as anode and cathode operated stably at 10 m A/cm^(2)for 120 h.In situ measurements and theoretical calculation reveal that the unique lattice oxygen mechanism path of RuO_(2)-IrO_(2)@CQDs can bypass the OOH^(*)intermediate and breaks the linear relationship of adsorbent evolution mechanism path,resulting in higher OER catalytic activity.
文摘Active multiple tuned mass dampers （referred to as AMTMD）, which consist of several active tuned mass dampers （ATMDs） with identical stiffness and damping coefficients but varying mass and control force, have recently been proposed to suppress undesirable oscillations of structures under ground acceleration. It has been shown that the AMTMD can remarkably improve the performance of multiple tuned mass dampers （MTMDs） and is also more effective in reducing structure oscillation than single ATMDs. Notwithstanding this, good performance of AMTMD （including a single ATMD illustrated from frequency-domain analysis） may not necessarily translate into a good seismic reduction behavior in the time-domain. To investigate these phenomena, a three-story steel structure model controlled by AMTMD with three ATMDs was implemented in SIMULINK and subjected to several historical earthquakes. Likewise, the structure under consideration was assumed to have uncertainty of stiffness, such as 4-15% of its initial stiffness, in the numerical simulations. The optimum design parameters of the AMTMD were obtained in the frequency-domain by implementing the minimization of the minimum values of the maximum dynamic magnification factors （DMF） of general structures with AMTMD. For comparison purposes, response analysis of the same structure with a single ATMD was also performed. The numerical analysis and comparison show that the AMTMD generally renders better effectiveness when compared with a single ATMD for structures subjected to historical earthquakes. In particular, the AMTMD can improve the effectiveness of a single ATMD for a structure with an uncertainty of stiffness of 4-15% of its initial stiffness.
文摘The wavelet transform method for high-quality time-frequency analysis is applied to sets of observations of relative sunspot numbers and stellar chromosphere fluxes of 10 Sun-like stars. Wavelet analysis of solar data shows that in a certain interval of time there are several cycles of activity with pe- riods of duration which vary considerably from each other： from quasi-biennial cycles to lO0-yr cycles. Cyclic activity was detected in almost all Sun-like stars that we examined, even those that previously were not considered as stars with cyclic activity according to analysis using a Scargle periodogram. The durations of solar and stellar cycles significantly change during the observation period.
文摘The 1.3-dipolar cycloaddition reaction of 2-trifluoromethyl- oxazolone and the activated carbon-carbon multiple bond was studied and gave a convenient way to synthesize 2-trifluoromethylpyrrole derivatives.
基金financially supported by the National Natural Science Foundation of China(No.52304335)China Postdoctoral Science Foundation(No.2023TQ0303)+3 种基金the Postdoctoral Fellowship Program of CPSF(No.GZC20232450)the Project of Zhongyuan Critical Metals Laboratory(Nos.GJJSGFYQ202305 and GJJSGFJQ202302)the Youth Science and technology innovation of Henan Province(No.23HASTIT009)Henan Province Youth Talent Support Program(2022)。
文摘The electrochemical reaction rate strongly depends on the pH of the solution and the relatively sluggish alkaline hydrogen evolution reaction(HER)process,attributed to alterations in the type of proton donor and binding energy,has consistently presented a significant challenge.Here,we report a new method for boosting alkaline HER via spontaneous built-in electric field strategy employed on cobalt phosphide nanofibers(NFs)electrocatalyst.The anion-cation dual-introduction of V and N on the NFs not only increases the electrochemical surface area but also enhances the catalytic activity,thereby elevating the performance of alkaline HER.An investigation strategy combining experiments and calculations revealed the charge transfer law between multiple active components and the enhanced regulation mechanism of alkaline HER process,ultimately achieving a nearly twice increase in reaction overpotential of the as-fabricated catalyst at-10 mA·cm^(-2).This new approach provides a potential strategy for improving the efficiency of core catalyst for energy conversion technologies.
基金support from the Natural Science Funds for Distinguished Young Scholar of Heilongjiang Province(No.JC2018004).
文摘Electrocatalytic synthesis of urea through C-N bond formation,converting carbon dioxide(CO_(2))and ni-trate(NO_(3)^(-)),presents a promising,less energy-intensive alternative to industrial urea production process.In this communication,we report the application of Mo_(2)C nanosheets-decorated carbon sheets(Mo_(2)C/C)as a highly efficient electrocatalyst for facilitating C-N coupling in ambient urea electrosynthesis.In CO_(2)-saturated 0.2 mol/L Na_(2)SO_(4)solution containing 0.05 mol/L NO_(3)^(-),the Mo_(2)C/C catalyst achieves an impres-sive urea yield of 579.13μg h^(-1)mg^(-1)with high Faradaic efficiency of 44.80%at-0.5 V versus the reversible hydrogen electrode.Further theoretical calculations reveal that the multiple Mo active sites enhance the formation of^(∗)CO and^(∗)NH_(2)intermediates and facilitate their C-N coupling.This research propels the use of Mo_(2)C-based electrodes in electrocatalysis and accentuates the capabilities of binary metal-based catalysts in C-N coupling reactions.
基金supported by the National Key R&D Program of China(2021YFB3600605)the National Natural Science Foundation of China(52173282,22105084)the Guangdong Basic and Applied Basic Research Foundation(2024A1515012053,2023A050502-0012)。
文摘Developing chiral thermally activated delayed fluorescence(TADF)materials with excellent photophysical and chiroptical properties is crucial for advancing circularly polarized organic light-emitting diodes(CP-OLED).To overcome the inherent trade-off relationship between photoluminescent quantum yield(PLQY)and dissymmetry factor(g),a fixed degenerate exciton chirality(FD-EC)strategy based on the multiple resonance TADF chromophore is proposed,exhibiting improved deep-blue emission with the peak at 454 nm and a high PLQY of 0.96,and unique exciton chirality with amplified|gabs|and|gPL|values of 1.0×10^(-3) and 1.6×10^(-3).The CP-OLED,incorporating the chiral blue emitter,exhibits standard blue emission with a narrow full width at half maximum of 30 nm,a superior external quantum efficiency of 27.8%,Commission Internationale de L'Eclairage coordinates of(0.14,0.08),and distinct circularly polarized electroluminescence.
基金Funding of Jiangsu Innovation Program for Graduate Education (CXLX11_0213)Aeronautical Science Foundation of China (2010ZB52011)
文摘A new hybrid control scheme is presented with a robust multiple model fusion control（RMMFC） law for a UH-60 helicopter and an active disturbance rejection control（ADRC） controller for its engines.This scheme is a control design method with every subsystem designed separately but fully considering the couplings between them.With three subspaces with respect to forward flight velocity,a RMMFC is proposed to devise a four-loop reference signal tracing control for the helicopter,which escapes the closed-loop system from unstable state due to the extreme complexity of this integrated nonlinear system.The engines are controlled by the proposed ADRC decoupling controller,which fully takes advantage of a good compensation ability for unmodeled dynamics and extra disturbances,so as to compensate torque disturbance in power turbine speed loop.By simulating a forward acceleration flight task,the RMMFC for the helicopter is validated.It is apparent that the integrated helicopter and engine system（IHES） has much better dynamic performance under the new control scheme.Especially in the switching process,the large transient is significantly weakened,and smooth transition among candidate controllers is achieved.Over the entire simulation task,the droop of power turbine speed with the proposed ADRC controller is significantly slighter than with the conventional PID controller,and the response time of the former is much faster than the latter.By simulating a rapid climb and descent flight task,the results also show the feasibility for the application of the proposed multiple model fusion control.Although there is aggressive power demand in this maneuver,the droop of power turbine speed with an ADRC controller is smaller than using a PID controller.The control performance for helicopter and engine is enhanced by adopting this hybrid control scheme,and simulation results in other envelope state give proofs of robustness for this new scheme.
文摘Interleukin 6(IL-6) is known as hybridoma cell growth factor,B-cell differentiating factor and so on One of its important biological functions in to induce
基金supported by the National Natural Science Foundation of China(92256304,U23A20593)。
文摘Chiral luminescence materials have potential applications in the field of three-dimensional displays due to their circularly polarized luminescence(CPL)characteristics.However,the further development of circularly polarized organic light-emitting diodes(CP-OLEDs)needs to meet the requirements of high efficiency,high color purity,low cost,and high dissymmetry factor(gPLor gEL),chiral multiple resonance thermally activated delayed fluorescence(MR-TADF)materials are considered as candidates in these aspects.Herein,based on a pair of chiral spirofluorene precursors,two pairs of high-performance chiral MR-TADF emitters((R/S)-p-Spiro-DtBuCzB and(R/S)-m-Spiro-DtBuCzB)are developed,which exhibit strong emissions peaking at 491 and 502 nm in toluene with full-width at half-maximum values of 25 and 33 nm,respectively.In addition,small singlet–triplet energy gaps of 0.15 and 0.10 eV with high absolute photoluminescence efficiencies of 95.0%and 96.7%are observed for p-Spiro-DtBuCzB and m-Spiro-DtBuCzB molecules,respectively.OLEDs based on p-Spiro-DtBuCzB and m-Spiro-DtBuCzB display high maximum external quantum efficiencies of 29.6%and 33.8%,respectively.Most importantly,CP-OLEDs present symmetric circularly polarized electroluminescence spectra with|gEL|factors of 3.36×10^(-4)and 7.66×10^(-4)for devices based on(R/S)-p-Spiro-DtBuCzB and(R/S)-m-Spiro-DtBuCzB enantiomers,respectively.
基金supported by the Guangdong Basic and Applied Basic Research Foundation(Nos.2023A1515110260 and 2023A1515140049)Special Projects in Key Areas of the Guangdong Provincial Department of Education(No.2024ZDZX2093).
文摘At present,excessive carbon dioxide(CO_(2))emission has become an increasingly prominent global energy and environmental issue.Therefore,effective methods to convert CO_(2) into fine chemicals are urgently required.Herein,series of S-doped carbon-nitrogen(CNS-X)materials(where X denotes the ratio of thiourea and melamine substances ranging from 0.03 to 0.8)was prepared via the programmed temperature pyrolysis method,which thiourea(CH4N_(2)S)and melamine was used as the precursor of the catalysts.The sulfur source endow the CNS-X acidic sites,which cooperate synergistically with amino groups from the incomplete polymerization of melamine,leading to a bifunctional catalyst for cycloaddition reaction of CO_(2) with epoxides.These catalysts were characterized using X-ray diffraction,Fourier transform infrared spectroscopy,elemental analysis,X-ray photoelectron spectroscopy,and N_(2) adsorption-desorption techniques,confirming the successful integration of functional groups.The optimal thiourea doping concentration of 0.4 was certainly found to have considerably facilitated the efficient conversion of CO_(2) by the CNS-0.4 catalyst,in which the conversion of epichlorohydrin(ECH)could achieve over 90.0% and the selectivity of cyclic carbonate is 98.0% under 1.0 MPa at 140℃ for 10 h.The superior catalytic performance of CNS-0.4 was attributable to the synergistic effect arising from the co-existence of Lewis acidic and basic sites.Notably,using CNS-0.4 resulted in a high yield even after four reaction cycles.
基金financially supported by National Natural Science Foundation of China(22172077,T2322013)the Scientific Research Foundation of Chemistry and Chemical Engineering Guangdong Laboratory(2011001)the support by the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(2018M3D1A1058624,2019R1A2C3010479)。
基金the National Natural Science Foundation of China(No.22271203)the State Key Laboratory of Organometallic Chemistry of Shanghai Institute of Organic Chemistry(No.KF2021005)the Collaborative Innovation Center of Suzhou Nano Science and Technology,the Priority Academic Program Development of Jiangsu Higher Education Institutions,and the Project of Scientific and Technologic Infrastructure of Suzhou(No.SZS201905).
文摘The coexistence of multi-component active sites like single-atom sites,diatomic sites(DAS)and nanoclusters is shown to result in superior performances in the hydrogen evolution reaction(HER).Metal diatomic sites are more complex than single-atom sites but their unique electronic structures can lead to significant enhancement of the HER kinetics.Although the synthesis and identification of DAS is usually challenging,we report a simple access to a diatomic catalyst by anchoring Co-Ru DAS on nitrogen-doped carbon supports along with Ru nanoparticles(NPs).Experimental and theoretical results revealed the atomic-level characteristics of Co-Ru sites,their strong electronic coupling and their synergy with Ru NPs within the catalyst.The unique electronic structure of the catalyst resulted in an excellent HER activity and stability in alkaline media.This work provides a valuable insight into a widely applicable design of diatomic catalysts with multi-component active sites for highly efficient HER electrocatalysis.
