The El Niño-Southern Oscillation(ENSO)is a naturally recurring interannual climate fluctuation that affects the global climate system.The advent of deep learning-based approaches has led to transformative changes...The El Niño-Southern Oscillation(ENSO)is a naturally recurring interannual climate fluctuation that affects the global climate system.The advent of deep learning-based approaches has led to transformative changes in ENSO forecasts,resulting in significant progress.Most deep learning-based ENSO prediction models which primarily rely solely on reanalysis data may lead to challenges in intensity underestimation in long-term forecasts,reducing the forecasting skills.To this end,we propose a deep residual-coupled model prediction(Res-CMP)model,which integrates historical reanalysis data and coupled model forecast data for multiyear ENSO prediction.The Res-CMP model is designed as a lightweight model that leverages only short-term reanalysis data and nudging assimilation prediction results of the Community Earth System Model(CESM)for effective prediction of the Niño 3.4 index.We also developed a transfer learning strategy for this model to overcome the limitations of inadequate forecast data.After determining the optimal configuration,which included selecting a suitable transfer learning rate during training,along with input variables and CESM forecast lengths,Res-CMP demonstrated a high correlation ability for 19-month lead time predictions(correlation coefficients exceeding 0.5).The Res-CMP model also alleviated the spring predictability barrier(SPB).When validated against actual ENSO events,Res-CMP successfully captured the temporal evolution of the Niño 3.4 index during La Niña events(1998/99 and 2020/21)and El Niño events(2009/10 and 2015/16).Our proposed model has the potential to further enhance ENSO prediction performance by using coupled models to assist deep learning methods.展开更多
The difficulty in achieving a balance between photocatalytic efficiency and chemical robustness has been a barrier to the broad use of MgO as a versatile material,mainly because of its restricted surface activity.To o...The difficulty in achieving a balance between photocatalytic efficiency and chemical robustness has been a barrier to the broad use of MgO as a versatile material,mainly because of its restricted surface activity.To overcome this,a novel surface modification technique is proposed.It involves the integration of highly stable SnO_(2) and WO_(3) nanoparticles,which are known to enhance surface activity.This approach aims to achieve an optimal balance between efficiency and stability by finely tuning the structure-surface reactivity relationship.The technique utilizes a plasma electrolytic oxidation(PEO)method.In this method,both the AZ31 Mg alloy substrate and SnO_(2)/WO_(3) precursors undergo simultaneous oxidation.This is induced by high-energy plasma generated through high voltage.The results demonstrate that this process yields a MgO layer with a homogeneous dispersion of SnO_(2) and WO3nanoparticles,significantly enhancing its overall performance.Corrosion measurements demonstrated enhanced electrochemical stability against chloride ions.The dual incorporation resulted in a hybrid film exhibiting a corrosion current density value of 7.57×10^(-11)A/cm^(2)and a high outer layer resistance of 5.17×10^(7)Ω.cm^(2).Additionally,the dual incorporation of SnO2and WO3nanoparticles enhances the photocatalytic activity of AZ31 Mg towards tetracycline degradation.This results in a photocatalytic efficiency of 89.54%within 2 h of exposure to visible light using the BA-W-Sn sample,which outperforms other samples.This integrated strategy enables the study to contribute significantly to expanding the practical applications of Mg O-based materials.It does so by simultaneously enhancing their photocatalytic activity and chemical stability.展开更多
Abstract: Several potential insecticides were synthesized by incorporating chrysanthemic acid and O,O-dialkyl phosphorodithioate through a pyrrolongdine-2,5-dione group. Their structures were determined by elementary ...Abstract: Several potential insecticides were synthesized by incorporating chrysanthemic acid and O,O-dialkyl phosphorodithioate through a pyrrolongdine-2,5-dione group. Their structures were determined by elementary analysis, NMR, IR and MS.展开更多
A tunable frequency-multiplying optoelectronic oscillator(OEO) based on a dual-parallel Mach-Zehnder modulator(DPMZM) is proposed and experimentally demonstrated. In the proposed system, the tunable fundamental microw...A tunable frequency-multiplying optoelectronic oscillator(OEO) based on a dual-parallel Mach-Zehnder modulator(DPMZM) is proposed and experimentally demonstrated. In the proposed system, the tunable fundamental microware signal is generated by a tunable optoelectronic oscillator incorporating a phase-shifted fiber Bragg grating(PS-FBG). By adjusting the DC bias of the DPMZM, the frequency-doubled microwave signal with a tunable frequency range from 11 GHz to 20 GHz and the frequency-quadrupled microwave signal with a tunable frequency range from 22.5 GHz to 26 GHz are generated. The phase noises of the fundamental, frequency-doubled and frequency-quadrupled signals at 10 k Hz offset frequency are-105.9 d Bc/Hz,-103.3 d Bc/Hz and-86.2 d Bc/Hz, respectively.展开更多
An analytical simulation based on a new model incorporating surface interaction is conducted to study the slip phenomenon in the Couette flow at different scales. The velocity profile is calculated by taking account o...An analytical simulation based on a new model incorporating surface interaction is conducted to study the slip phenomenon in the Couette flow at different scales. The velocity profile is calculated by taking account of the micro-force between molecules and macro-force from the viscous shearing effect, as they contribute to the achieve- ment of the slip length. The calculated results are compared with those obtained from the molecular dynamics simulation, showing an excellent agreement. Further, the effect of the shear rate on the slip is investigated. The results can well predict the fluid flow behaviors on a solid substrate, but has to be proved by experiment.展开更多
This paper presents a new hybrid approach that combines Modified Priority List (MPL) with Charged System Search (CSS), termed MPL-CSS, to solve one of the most crucial power system’s operational optimization problems...This paper presents a new hybrid approach that combines Modified Priority List (MPL) with Charged System Search (CSS), termed MPL-CSS, to solve one of the most crucial power system’s operational optimization problems, known as unit commitment (UC) scheduling. The UC scheduling problem is a mixed-integer nonlinear problem, highly-dimensional and extremely constrained. Existing meta-heuristic UC solution methods have the problems of stopping at a local optimum and slow convergence when applied to large-scale, heavily-constrained UC applications. In the first step of the proposed method, initial hourly optimum solutions of UC are obtained by Modified Priority List (MPL);however, the obtained UC solution may still be possible to be further improved. Therefore, in the second step, the CSS is utilized to achieve higher quality solutions. The UC is formulated as mixed integer linear programming to ensure the tractability of the results. The proposed method is successfully applied to a popular test system up to 100 units generators for both 24-hr and 168-hr system. Computational results show that both solution cost and execution time are superior to those of published methods.展开更多
A series of succinimido-organophosphate analogueswas synthesized with maleic anhydride as starting material viamaleimide and its analogues as intermediates and characterized by IR,1HNMR and elementary analysis.
Three novel polymers incorporating Schiff bases,derived from condensation reactions of poly(acrylamide) with 5- chloro-2-hydroxybenzaldehyde,5-bromo-2-hydroxybenzaldehyde and 5-methyl-2-hydroxybenzaldehyde,have been s...Three novel polymers incorporating Schiff bases,derived from condensation reactions of poly(acrylamide) with 5- chloro-2-hydroxybenzaldehyde,5-bromo-2-hydroxybenzaldehyde and 5-methyl-2-hydroxybenzaldehyde,have been synthesized,and their Cu(Ⅱ) and Ni(Ⅱ) complexes have been prepared.The ~1H-NMR signals of the—CH=N—and—NH_2 groups have been utilized to determine the relative abundances of Schiff base and acrylamide groups in the polymers containing Schiff bases.Poly(acrylamide) incorporating Schiff bases and ...展开更多
A detailed investigation is presented for Love waves （LWs） with thick viscoelastic guiding layers. A theoretical calculation and an experiment are carried out for LW devices incorporating an SU-8 guiding layer, an S...A detailed investigation is presented for Love waves （LWs） with thick viscoelastic guiding layers. A theoretical calculation and an experiment are carried out for LW devices incorporating an SU-8 guiding layer, an ST-90° X quartz substrate and two 28-μm periodic interdigital transducers. Both the calculated and the measured results show an increase in propagation velocity when h / λ〉0.05. The measured insertion loss of LWs is consistent with the calculated propagation loss. The insertion loss of bulk waves is also measured and is compared with that of LWs.展开更多
Concentration of copper and zinc in isolated Suillus bovinus mycelia, used nutrient solution and 0.5 mol/L EDTA mycelia washing solution were measured to investigate the distribution of heavy metals in mycelia growth ...Concentration of copper and zinc in isolated Suillus bovinus mycelia, used nutrient solution and 0.5 mol/L EDTA mycelia washing solution were measured to investigate the distribution of heavy metals in mycelia growth in excess copper or zinc nutrient solution. Treated with zinc, most of added zinc maintained in used solution, and 9.8%/14.6% was in/on mycelia in treatment, and in treatment 2 was 3.9%/8.0% in/on mycelia. In the copper applications, copper stimulated in more than on mycelia, i.e., 25.9%/4.5% in/on mycelia in treatment, and 7%/18.8% in/on mycelia while most of copper retained in used nutrient solution. Certain amount of copper or zinc uptake by mycelia led to pronounced influence on glycolysis and nitrogen incorporating process of Suillus bovinus, while the tested enzymes kept constant in treatment. In crude extracts of copper treatment 2 mycelia, activities of HK, PFK and GS were inhibited and decrease to 63%, 48% and 38% and GIDH increased by 68% of the control, respectively. The behaviors of these tested enzymes toward zinc corresponded in general with that towards copper. The potential protection of Suillus bovinus for its host plant under excess copper or zinc threaten was discussed.展开更多
Developing highly active and cost-effective electrocatalysts for enhancing the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)is a significant challenge for overall water splitting.Sulfur-incorporat...Developing highly active and cost-effective electrocatalysts for enhancing the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)is a significant challenge for overall water splitting.Sulfur-incorporated nickel iron(oxy)hydroxide(S-NiFeOOH)nanosheets were directly grown on commercial nickel foam using a galvanic corrosion method and a hydrothermal method.The incorporation of sulfur into NiFeOOH enhanced the catalytic activity for the HER and OER in 1 M KOH electrolyte.The enhanced catalytic activity is attributed to the change in the local structure and chemical states due to the incorporation of sulfur.High performance for overall water splitting was achieved with an alkaline water electrolyzer.This was realized by employing S-NiFeOOH as a bifunctional electrocatalyst,thereby outperforming a water electrolyzer that requires the usage of precious metal electrocatalysts(i.e.,Pt/C as the HER electrocatalyst and IrO_(2) as the OER electrocatalyst).Moreover,when driven by a commercial silicon solar cell,an alkaline water electrolyzer that uses S-NiFeOOH as a bifunctional electrocatalyst generated hydrogen under natural illumination.This study shows that S-NiFeOOH is a promising candidate for a large-scale industrial implementation of hydrogen production for overall water splitting because of its low cost,high activity,and durability.In addition,the solar-driven water electrolyzer using S-NiFeOOH as a bifunctional electrocatalyst affords the opportunity for developing effective and feasible solar power systems in the future.展开更多
Heavy-fermion superconductors (HFSCs) are regarded as outside the purview of BCS theory because it is usually constrained by the inequality , where EF, μ, kB, and θD are, respectively, the Fermi energy, chemical pot...Heavy-fermion superconductors (HFSCs) are regarded as outside the purview of BCS theory because it is usually constrained by the inequality , where EF, μ, kB, and θD are, respectively, the Fermi energy, chemical potential, Boltzmann constant, and the Debye temperature. We show that this restriction can be removed by incorporating μ into the equations for Tc and the gap Δ0 at T = 0. Further, when μ kBθD, we curtail the limits of the equations for Tc and Δ0 to avoid complex-valued solutions. The resulting equations are applied to a prominent member of the HFSC family, i.e., CeCoIn5, by appealing to ideas due to Born and Karmann, Suhl et al., and Bianconi et al. Since the equations now contain an additional variable μ, we find that 1) the Tc of the SC can be accounted for by a multitude of values of the (μ, λ) pair, λ being the interaction parameter;2) the λ vs. μ plot has a dome-like structure when μ kBθD;3) the (μ, λ) values obtained in 2) lead to reasonable results for the range of each of the following variables: Δ0, s, and n, where s is the ratio of the mass of a conduction electron and the free electron mass and n is the number density of charge carriers in the SC.展开更多
Floods have become increasingly destructive with climate change,resulting in the inundation of urban metro systems.This study complied with global data on flooded metro lines in recent decades.Based on these data,a fr...Floods have become increasingly destructive with climate change,resulting in the inundation of urban metro systems.This study complied with global data on flooded metro lines in recent decades.Based on these data,a framework incorporating machine learning(ML)with geographic information system(GIS)was developed to predict flood susceptibility in urban metro systems.To address the scarcity of subway flooding data,this study proposed a novel approach to generate a database for training and testing using ML and GIS.The 7.20 flood event in Zhengzhou,China,was analyzed as a case study.The optimal ML model was selected by comparing predicted flood states with recorded flooded metro stations.Flood susceptibility for the Zhengzhou metro system under future extreme rainfall scenarios was then predicted.Results demonstrated that the number of flooded stations and their flood susceptibility increased with rainfall intensity.These findings highlight the scale and vulnerability of metro systems,providing critical insights for developing resilient underground infrastructure.展开更多
Polymer backbone plays a fundamental role in determining the molecular architecture and properties of polymers.Polymers can be modified by incorporating heteroatoms into their backbones to achieve tunable optical and ...Polymer backbone plays a fundamental role in determining the molecular architecture and properties of polymers.Polymers can be modified by incorporating heteroatoms into their backbones to achieve tunable optical and mechanical properties,such as polyamide,polythioether and polysilane[1].The transition from nonconjugated to conjugated backbones of polymers challenges the traditional view of polymers as insulators,leading to the development of conductive polymers[2].In contrast,metal elements far surpass non-metal elements in both the variety of elemental types and the diversity of their outer-shell electrons,incorporating which into the polymer backbone is promising to create polymer materials with unique properties and applications,such as high mechanical strength and electrical conductivity[3].Integration of metal atoms into the polymer backbones has been reported.However,the lack of uniformity and continuity in the interaction of metal atoms limits electron transfer efficiency and hinders the full utilization of metal elements within polymer materials[4].To this end,a novel metal-backboned polymer was proposed[5,6],wherein the polymer backbone consists entirely of metal atoms interconnected through metal–metal bonds.This novel polymer was found with exceptional optical and electrical properties,showing promising applications in photoelectric devices,flexible electronics,and microwave absorption materials[7,8].展开更多
THE expressive,exotic Argentina-born tango music has engrossed generations of Chinese audiences through films,album records,and radio stations since the twentieth century.Today,in China,a tango ensemble,called“To Mel...THE expressive,exotic Argentina-born tango music has engrossed generations of Chinese audiences through films,album records,and radio stations since the twentieth century.Today,in China,a tango ensemble,called“To Melody Ensemble”and composed of young graduates from the elite Central Conservatory of Music(CCOM),is exploring new dimensions by incorporating Chinese tunes into tango music.展开更多
High-performance lithium metal batteries benefit from the construction of composite polymer electrolytes(CPEs)which are synthesized by incorporating inorganic fillers into polymer matrices[1].However,the random distri...High-performance lithium metal batteries benefit from the construction of composite polymer electrolytes(CPEs)which are synthesized by incorporating inorganic fillers into polymer matrices[1].However,the random distribution of added fillers within the polymer matrix can lead to tortuous ion pathways and longer transmission distances(Fig.1).As a result,the ion transport capability of CPEs may decrease,while interface contact may deteriorate.Therefore,the organized arrangement of fillers emerges as a crucial consideration in constructing electrolyte membranes.One highly effective approach is the adoption of a vertically aligned filler configuration,where ceramic fillers are constructed to be perpendicular to the electrolyte membrane.If so,the filler/electrolyte interface impedance can be significantly reduced,while continuous ion transport channels along the specified direction are formed,thus significantly enhancing the ion conduction(Fig.1(a))[1].展开更多
We demonstrate a broad bandwidth multiwavelength laser based on a bidirectional Lyot filter and a semiconductor optical amplifier with a mechanism of intensity-dependent loss as the flatness agent. A wide bandwidth of...We demonstrate a broad bandwidth multiwavelength laser based on a bidirectional Lyot filter and a semiconductor optical amplifier with a mechanism of intensity-dependent loss as the flatness agent. A wide bandwidth of a multiwavelength spectrum of 32.9 nm within a 5 dB uniformity is obtained under optimized polarization param- eters. For this case, the number of generated lasing lines is 329 with a fixed wavelength separation of 0.1 nm. The power stability of this multiwavelength laser is less than 1.35 dB within 200 min time frame. This shows that the bidirectional Lyot filter provides an alternative option for multiwavelength generation in laser systems.展开更多
A polarization-maintained coupled optoelectronic oscillator（COEO） with its performance significantly improved by a short-length unpumped erbium-doped fiber（EDF） is reported and experimentally investigated.A 10 GHz...A polarization-maintained coupled optoelectronic oscillator（COEO） with its performance significantly improved by a short-length unpumped erbium-doped fiber（EDF） is reported and experimentally investigated.A 10 GHz optical pulse train with a supermode suppression ratio of 61.8 d B and a 10 GHz radio frequency signal with a sidemode suppression ratio of 94 d B and a phase noise of-121.9 d Bc∕Hz at 10 k Hz offset are simultaneously generated. Thanks to saturable absorption of the 1 m unpumped EDF, which introduces relatively large cavity loss to the undesired modes and noise, the supermode suppression ratio and the phase noise are improved by 9.4 and 7.9 d B, respectively.展开更多
Developing highly active and selective catalysts for the hydrogenation of nitroarenes,an environmentally benign process to produce industrially important aniline intermediates,is highly desirable but very challenging....Developing highly active and selective catalysts for the hydrogenation of nitroarenes,an environmentally benign process to produce industrially important aniline intermediates,is highly desirable but very challenging.Pd catalysts are generally recognized as active but nonselective catalysts for this important reaction.Here,we report an effective strategy to greatly improve the selectivity of Pd catalysts based on the reactive metal–support interaction.展开更多
-We describe a simple method to generate wavelength-tunable pulses by using a semiconductor optical amplifier (SOA) as an intensity modulator and a gain medium. Wavelength tunable pulses at a repetition rate of 4.8 GH...-We describe a simple method to generate wavelength-tunable pulses by using a semiconductor optical amplifier (SOA) as an intensity modulator and a gain medium. Wavelength tunable pulses at a repetition rate of 4.8 GHz have been generated.展开更多
基金The National Key Research and Development Program of China under contract Nos 2024YFF0808900,2023YFF0805300,and 2020YFA0608804the Civilian Space Programme of China under contract No.D040305.
文摘The El Niño-Southern Oscillation(ENSO)is a naturally recurring interannual climate fluctuation that affects the global climate system.The advent of deep learning-based approaches has led to transformative changes in ENSO forecasts,resulting in significant progress.Most deep learning-based ENSO prediction models which primarily rely solely on reanalysis data may lead to challenges in intensity underestimation in long-term forecasts,reducing the forecasting skills.To this end,we propose a deep residual-coupled model prediction(Res-CMP)model,which integrates historical reanalysis data and coupled model forecast data for multiyear ENSO prediction.The Res-CMP model is designed as a lightweight model that leverages only short-term reanalysis data and nudging assimilation prediction results of the Community Earth System Model(CESM)for effective prediction of the Niño 3.4 index.We also developed a transfer learning strategy for this model to overcome the limitations of inadequate forecast data.After determining the optimal configuration,which included selecting a suitable transfer learning rate during training,along with input variables and CESM forecast lengths,Res-CMP demonstrated a high correlation ability for 19-month lead time predictions(correlation coefficients exceeding 0.5).The Res-CMP model also alleviated the spring predictability barrier(SPB).When validated against actual ENSO events,Res-CMP successfully captured the temporal evolution of the Niño 3.4 index during La Niña events(1998/99 and 2020/21)and El Niño events(2009/10 and 2015/16).Our proposed model has the potential to further enhance ENSO prediction performance by using coupled models to assist deep learning methods.
基金National Research Foundation of Korea (NRF) funded by the Korean government (MSIT) (No. 2022R1A2C1006743)。
文摘The difficulty in achieving a balance between photocatalytic efficiency and chemical robustness has been a barrier to the broad use of MgO as a versatile material,mainly because of its restricted surface activity.To overcome this,a novel surface modification technique is proposed.It involves the integration of highly stable SnO_(2) and WO_(3) nanoparticles,which are known to enhance surface activity.This approach aims to achieve an optimal balance between efficiency and stability by finely tuning the structure-surface reactivity relationship.The technique utilizes a plasma electrolytic oxidation(PEO)method.In this method,both the AZ31 Mg alloy substrate and SnO_(2)/WO_(3) precursors undergo simultaneous oxidation.This is induced by high-energy plasma generated through high voltage.The results demonstrate that this process yields a MgO layer with a homogeneous dispersion of SnO_(2) and WO3nanoparticles,significantly enhancing its overall performance.Corrosion measurements demonstrated enhanced electrochemical stability against chloride ions.The dual incorporation resulted in a hybrid film exhibiting a corrosion current density value of 7.57×10^(-11)A/cm^(2)and a high outer layer resistance of 5.17×10^(7)Ω.cm^(2).Additionally,the dual incorporation of SnO2and WO3nanoparticles enhances the photocatalytic activity of AZ31 Mg towards tetracycline degradation.This results in a photocatalytic efficiency of 89.54%within 2 h of exposure to visible light using the BA-W-Sn sample,which outperforms other samples.This integrated strategy enables the study to contribute significantly to expanding the practical applications of Mg O-based materials.It does so by simultaneously enhancing their photocatalytic activity and chemical stability.
文摘Abstract: Several potential insecticides were synthesized by incorporating chrysanthemic acid and O,O-dialkyl phosphorodithioate through a pyrrolongdine-2,5-dione group. Their structures were determined by elementary analysis, NMR, IR and MS.
基金supported by the National Key R&D Program of China (No.2018YFB1801003)the National Natural Science Foundation of China (Nos.61525501 and 61827817)+1 种基金the Beijing Natural Science Foundation (No.4192022)the Project of Shandong Province Higher Educational Science and Technology Program (No.J17KA089)。
文摘A tunable frequency-multiplying optoelectronic oscillator(OEO) based on a dual-parallel Mach-Zehnder modulator(DPMZM) is proposed and experimentally demonstrated. In the proposed system, the tunable fundamental microware signal is generated by a tunable optoelectronic oscillator incorporating a phase-shifted fiber Bragg grating(PS-FBG). By adjusting the DC bias of the DPMZM, the frequency-doubled microwave signal with a tunable frequency range from 11 GHz to 20 GHz and the frequency-quadrupled microwave signal with a tunable frequency range from 22.5 GHz to 26 GHz are generated. The phase noises of the fundamental, frequency-doubled and frequency-quadrupled signals at 10 k Hz offset frequency are-105.9 d Bc/Hz,-103.3 d Bc/Hz and-86.2 d Bc/Hz, respectively.
基金Supported by the National Natural Science Foundation of China under Grant No 51305033the Ministry of National Defense of China under Grant No 9140C340506
文摘An analytical simulation based on a new model incorporating surface interaction is conducted to study the slip phenomenon in the Couette flow at different scales. The velocity profile is calculated by taking account of the micro-force between molecules and macro-force from the viscous shearing effect, as they contribute to the achieve- ment of the slip length. The calculated results are compared with those obtained from the molecular dynamics simulation, showing an excellent agreement. Further, the effect of the shear rate on the slip is investigated. The results can well predict the fluid flow behaviors on a solid substrate, but has to be proved by experiment.
文摘This paper presents a new hybrid approach that combines Modified Priority List (MPL) with Charged System Search (CSS), termed MPL-CSS, to solve one of the most crucial power system’s operational optimization problems, known as unit commitment (UC) scheduling. The UC scheduling problem is a mixed-integer nonlinear problem, highly-dimensional and extremely constrained. Existing meta-heuristic UC solution methods have the problems of stopping at a local optimum and slow convergence when applied to large-scale, heavily-constrained UC applications. In the first step of the proposed method, initial hourly optimum solutions of UC are obtained by Modified Priority List (MPL);however, the obtained UC solution may still be possible to be further improved. Therefore, in the second step, the CSS is utilized to achieve higher quality solutions. The UC is formulated as mixed integer linear programming to ensure the tractability of the results. The proposed method is successfully applied to a popular test system up to 100 units generators for both 24-hr and 168-hr system. Computational results show that both solution cost and execution time are superior to those of published methods.
文摘A series of succinimido-organophosphate analogueswas synthesized with maleic anhydride as starting material viamaleimide and its analogues as intermediates and characterized by IR,1HNMR and elementary analysis.
基金supported by the Gazi University Research Fund(NoFEF05/2006-22)TUBITAK(No106T734(TBAG/HD-232))
文摘Three novel polymers incorporating Schiff bases,derived from condensation reactions of poly(acrylamide) with 5- chloro-2-hydroxybenzaldehyde,5-bromo-2-hydroxybenzaldehyde and 5-methyl-2-hydroxybenzaldehyde,have been synthesized,and their Cu(Ⅱ) and Ni(Ⅱ) complexes have been prepared.The ~1H-NMR signals of the—CH=N—and—NH_2 groups have been utilized to determine the relative abundances of Schiff base and acrylamide groups in the polymers containing Schiff bases.Poly(acrylamide) incorporating Schiff bases and ...
基金Supported by the National Natural Science Foundation of China under Grant No 11104314
文摘A detailed investigation is presented for Love waves （LWs） with thick viscoelastic guiding layers. A theoretical calculation and an experiment are carried out for LW devices incorporating an SU-8 guiding layer, an ST-90° X quartz substrate and two 28-μm periodic interdigital transducers. Both the calculated and the measured results show an increase in propagation velocity when h / λ〉0.05. The measured insertion loss of LWs is consistent with the calculated propagation loss. The insertion loss of bulk waves is also measured and is compared with that of LWs.
文摘Concentration of copper and zinc in isolated Suillus bovinus mycelia, used nutrient solution and 0.5 mol/L EDTA mycelia washing solution were measured to investigate the distribution of heavy metals in mycelia growth in excess copper or zinc nutrient solution. Treated with zinc, most of added zinc maintained in used solution, and 9.8%/14.6% was in/on mycelia in treatment, and in treatment 2 was 3.9%/8.0% in/on mycelia. In the copper applications, copper stimulated in more than on mycelia, i.e., 25.9%/4.5% in/on mycelia in treatment, and 7%/18.8% in/on mycelia while most of copper retained in used nutrient solution. Certain amount of copper or zinc uptake by mycelia led to pronounced influence on glycolysis and nitrogen incorporating process of Suillus bovinus, while the tested enzymes kept constant in treatment. In crude extracts of copper treatment 2 mycelia, activities of HK, PFK and GS were inhibited and decrease to 63%, 48% and 38% and GIDH increased by 68% of the control, respectively. The behaviors of these tested enzymes toward zinc corresponded in general with that towards copper. The potential protection of Suillus bovinus for its host plant under excess copper or zinc threaten was discussed.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(No.NRF-2016R1D1A3B04935101).
文摘Developing highly active and cost-effective electrocatalysts for enhancing the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)is a significant challenge for overall water splitting.Sulfur-incorporated nickel iron(oxy)hydroxide(S-NiFeOOH)nanosheets were directly grown on commercial nickel foam using a galvanic corrosion method and a hydrothermal method.The incorporation of sulfur into NiFeOOH enhanced the catalytic activity for the HER and OER in 1 M KOH electrolyte.The enhanced catalytic activity is attributed to the change in the local structure and chemical states due to the incorporation of sulfur.High performance for overall water splitting was achieved with an alkaline water electrolyzer.This was realized by employing S-NiFeOOH as a bifunctional electrocatalyst,thereby outperforming a water electrolyzer that requires the usage of precious metal electrocatalysts(i.e.,Pt/C as the HER electrocatalyst and IrO_(2) as the OER electrocatalyst).Moreover,when driven by a commercial silicon solar cell,an alkaline water electrolyzer that uses S-NiFeOOH as a bifunctional electrocatalyst generated hydrogen under natural illumination.This study shows that S-NiFeOOH is a promising candidate for a large-scale industrial implementation of hydrogen production for overall water splitting because of its low cost,high activity,and durability.In addition,the solar-driven water electrolyzer using S-NiFeOOH as a bifunctional electrocatalyst affords the opportunity for developing effective and feasible solar power systems in the future.
文摘Heavy-fermion superconductors (HFSCs) are regarded as outside the purview of BCS theory because it is usually constrained by the inequality , where EF, μ, kB, and θD are, respectively, the Fermi energy, chemical potential, Boltzmann constant, and the Debye temperature. We show that this restriction can be removed by incorporating μ into the equations for Tc and the gap Δ0 at T = 0. Further, when μ kBθD, we curtail the limits of the equations for Tc and Δ0 to avoid complex-valued solutions. The resulting equations are applied to a prominent member of the HFSC family, i.e., CeCoIn5, by appealing to ideas due to Born and Karmann, Suhl et al., and Bianconi et al. Since the equations now contain an additional variable μ, we find that 1) the Tc of the SC can be accounted for by a multitude of values of the (μ, λ) pair, λ being the interaction parameter;2) the λ vs. μ plot has a dome-like structure when μ kBθD;3) the (μ, λ) values obtained in 2) lead to reasonable results for the range of each of the following variables: Δ0, s, and n, where s is the ratio of the mass of a conduction electron and the free electron mass and n is the number density of charge carriers in the SC.
基金supported by the National Natural Science Foundation of China(Grant No.42007416)the Key R&D Program of the Ministry of Science and Technology of China(Grant No.2024YFC3013303)the Research Grants Council(RGC)of Hong Kong Special Administrative Region Government of China(Grant Nos.E-PolyU501/24,T22-607/24-N).
文摘Floods have become increasingly destructive with climate change,resulting in the inundation of urban metro systems.This study complied with global data on flooded metro lines in recent decades.Based on these data,a framework incorporating machine learning(ML)with geographic information system(GIS)was developed to predict flood susceptibility in urban metro systems.To address the scarcity of subway flooding data,this study proposed a novel approach to generate a database for training and testing using ML and GIS.The 7.20 flood event in Zhengzhou,China,was analyzed as a case study.The optimal ML model was selected by comparing predicted flood states with recorded flooded metro stations.Flood susceptibility for the Zhengzhou metro system under future extreme rainfall scenarios was then predicted.Results demonstrated that the number of flooded stations and their flood susceptibility increased with rainfall intensity.These findings highlight the scale and vulnerability of metro systems,providing critical insights for developing resilient underground infrastructure.
基金supported by the Ministry of Science and Technology of the People’s Republic of China(2022YFA1203001 and 2022YFA1203002)the National Natural Science Foundation of China(T2321003,22335003,and 22105045)Science and Technology Commission of Shanghai Municipality(21511104900 and 20JC1414902).
文摘Polymer backbone plays a fundamental role in determining the molecular architecture and properties of polymers.Polymers can be modified by incorporating heteroatoms into their backbones to achieve tunable optical and mechanical properties,such as polyamide,polythioether and polysilane[1].The transition from nonconjugated to conjugated backbones of polymers challenges the traditional view of polymers as insulators,leading to the development of conductive polymers[2].In contrast,metal elements far surpass non-metal elements in both the variety of elemental types and the diversity of their outer-shell electrons,incorporating which into the polymer backbone is promising to create polymer materials with unique properties and applications,such as high mechanical strength and electrical conductivity[3].Integration of metal atoms into the polymer backbones has been reported.However,the lack of uniformity and continuity in the interaction of metal atoms limits electron transfer efficiency and hinders the full utilization of metal elements within polymer materials[4].To this end,a novel metal-backboned polymer was proposed[5,6],wherein the polymer backbone consists entirely of metal atoms interconnected through metal–metal bonds.This novel polymer was found with exceptional optical and electrical properties,showing promising applications in photoelectric devices,flexible electronics,and microwave absorption materials[7,8].
文摘THE expressive,exotic Argentina-born tango music has engrossed generations of Chinese audiences through films,album records,and radio stations since the twentieth century.Today,in China,a tango ensemble,called“To Melody Ensemble”and composed of young graduates from the elite Central Conservatory of Music(CCOM),is exploring new dimensions by incorporating Chinese tunes into tango music.
基金supported by the National Natural Science Foundation of China(No.51972293)Hangzhou Key Research Program Project(2023SZD0099)LingYan Project(2024C01090).
文摘High-performance lithium metal batteries benefit from the construction of composite polymer electrolytes(CPEs)which are synthesized by incorporating inorganic fillers into polymer matrices[1].However,the random distribution of added fillers within the polymer matrix can lead to tortuous ion pathways and longer transmission distances(Fig.1).As a result,the ion transport capability of CPEs may decrease,while interface contact may deteriorate.Therefore,the organized arrangement of fillers emerges as a crucial consideration in constructing electrolyte membranes.One highly effective approach is the adoption of a vertically aligned filler configuration,where ceramic fillers are constructed to be perpendicular to the electrolyte membrane.If so,the filler/electrolyte interface impedance can be significantly reduced,while continuous ion transport channels along the specified direction are formed,thus significantly enhancing the ion conduction(Fig.1(a))[1].
文摘We demonstrate a broad bandwidth multiwavelength laser based on a bidirectional Lyot filter and a semiconductor optical amplifier with a mechanism of intensity-dependent loss as the flatness agent. A wide bandwidth of a multiwavelength spectrum of 32.9 nm within a 5 dB uniformity is obtained under optimized polarization param- eters. For this case, the number of generated lasing lines is 329 with a fixed wavelength separation of 0.1 nm. The power stability of this multiwavelength laser is less than 1.35 dB within 200 min time frame. This shows that the bidirectional Lyot filter provides an alternative option for multiwavelength generation in laser systems.
基金supported by the National Natural Science Foundation of China(No.61422108)the Natural Science Foundation of Jiangsu Province(No.BK20160082)+1 种基金the Jiangsu Provincial Program for High-level Talents in Six Areas(No.DZXX-030)the Fundamental Research Funds for Central Universities(Nos.NE2017002 and NS2016037)
文摘A polarization-maintained coupled optoelectronic oscillator（COEO） with its performance significantly improved by a short-length unpumped erbium-doped fiber（EDF） is reported and experimentally investigated.A 10 GHz optical pulse train with a supermode suppression ratio of 61.8 d B and a 10 GHz radio frequency signal with a sidemode suppression ratio of 94 d B and a phase noise of-121.9 d Bc∕Hz at 10 k Hz offset are simultaneously generated. Thanks to saturable absorption of the 1 m unpumped EDF, which introduces relatively large cavity loss to the undesired modes and noise, the supermode suppression ratio and the phase noise are improved by 9.4 and 7.9 d B, respectively.
基金funding support from the National Natural Science Foundation of China(grant nos.U1932213,21431006,51732011,and 21761132008)the Foundation for Innovative Research Groups of the National Natural Sci-ence Foundationof China(grant no.21521001)+4 种基金and the Key Research Program of Frontier Sciences,CAS(grant no.QYZDJ-SSW-SLH036).H.W.L.is thankful for the support by the National Key Research and Development Program of China(no.2018YFA0702001)and the Fundamental Re-search Funds for the Central Universities(no.WK206-0190103).Z.Y.W.acknowledges the funding support from the National Natural Science Foundation of China(grant no.21703229)C.Q.H acknowledges the funding support from the Zhejiang Provincial Natural Science Foundation of Chi-na(grant no.LQ20B030008).W.X.L acknowledges the funding support from the National Natural Science Foun-dation of China(grant nos.91645202 and 91945302)the Key Research Programof Frontier Sciences,CAS(grantno.QYZDJ-SSW-SLH054)and the National Key Research and Development Program of China(grant nos.2018YFA-0208603 and 2017YFB0602205)partially carried out at the USTC Center for Micro and Nanoscale Research and Fabrication.
文摘Developing highly active and selective catalysts for the hydrogenation of nitroarenes,an environmentally benign process to produce industrially important aniline intermediates,is highly desirable but very challenging.Pd catalysts are generally recognized as active but nonselective catalysts for this important reaction.Here,we report an effective strategy to greatly improve the selectivity of Pd catalysts based on the reactive metal–support interaction.
文摘-We describe a simple method to generate wavelength-tunable pulses by using a semiconductor optical amplifier (SOA) as an intensity modulator and a gain medium. Wavelength tunable pulses at a repetition rate of 4.8 GHz have been generated.
