Electrochemical C-C and C-N coupling reactions with the conversion of abundant and inexpensive small molecules,such as CO_(2) and nitrogencontaining species,are considered a promising route for increasing the value of...Electrochemical C-C and C-N coupling reactions with the conversion of abundant and inexpensive small molecules,such as CO_(2) and nitrogencontaining species,are considered a promising route for increasing the value of CO_(2) reduction products.The development of high-performance catalysts is the key to the both electrocatalytic reactions.In this review,we present a systematic summary of the reaction systems for electrocatalytic CO_(2) reduction,along with the coupling mechanisms of C-C and C-N bonds over outstanding electrocatalytic materials recently developed.The key intermediate species and reaction pathways related to the coupling as well as the catalyst-structure relationship will be also discussed,aiming to provide insights and guidance for designing efficient CO_(2) reduction systems.展开更多
Photothermal catalytic CO_(2) conversion provides an effective solution targeting carbon neutrality by synergistic utilization of photon and heat.However,the C-C coupling initiated by photothermal catalysis is still a...Photothermal catalytic CO_(2) conversion provides an effective solution targeting carbon neutrality by synergistic utilization of photon and heat.However,the C-C coupling initiated by photothermal catalysis is still a big challenge.Herein,a three-dimensional(3D)hierarchical W_(18)O_(49)/WTe_(2) hollow nanosphere is constructed through in-situ embodying of oxygen vacancy and tellurium on the scaffold of WO_(3).The light absorption towards near-infrared spectral region and CO_(2) adsorption are enhanced by the formation of half-metal WTe_(2) and the unique hierarchical hollow architecture.Combining with the generation of oxygen vacancy with strengthened CO_(2) capture,the photothermal effect on the samples can be sufficiently exploited for activating the CO_(2) molecules.In particular,the close contact between W_(18)O_(49)and WTe_(2) largely promotes the photoinduced charge separation and mass transfer,and thus the~*CHO intermediate formation and fixedness are facilitated.As a result,the C-C coupling can be evoked between tungsten and tellurium atoms on WTe_(2).The ethylene production by optimized W_(18)O_(49)/WTe_(2) reaches 147.6μmol g^(-1)with the selectivity of 80%.The in-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)and density functional theory(DFT)calculations are performed to unveil the presence and significance of aldehyde intermediate groups in C-C coupling.The half-metallic WTe_(2) cocatalyst proposes a new approach for efficient CO_(2) conversion with solar energy,and may especially create a new platform for the generation of multi-carbon products.展开更多
Steering the directional carrier migration across the interface is a central mission for efficient photocatalytic reactions.In this work,an atomic-shared heterointerface is constructed between the defect-rich ZnIn_(2)...Steering the directional carrier migration across the interface is a central mission for efficient photocatalytic reactions.In this work,an atomic-shared heterointerface is constructed between the defect-rich ZnIn_(2)S_(4)(HVs-ZIS)and CoIn_(2)S_(4)(CIS)via a defect-guided heteroepitaxial growth strategy.The strong interface coupling induces adequate carriers exchanging passageway between HVs-ZIS and CIS,enhancing the internal electric field(IEF)in the ZnIn_(2)S_(4)/CoIn_(2)S_(4)(HVs-ZIS/CIS)heterostructure.The defect structure in HVs-ZIS induces an additional defect level,improving the separation efficiency of photocarriers.Moreover,promoted by the IEF and intimate heterointerface,photogenerated electrons trapped by the defect level can migrate to the valence band of CIS,contributing to massive photogenerated electrons with intense reducibility in HVs-ZIS/CIS.Consequently,the HVs-ZIS/CIS heterostructure performs a boosted H_(2)evolution activity of 33.65 mmol g^(-1)h^(-1).This work highlights the synergistic effects of defect and strong interface coupling in regulating carrier transfer and paves a brave avenue for constructing efficient heterostructure photocatalysts.展开更多
High qualityβ-Ga_(2)O_(3)single crystal nanobelts with length of 2−3 mm and width from tens of microns to 132μm were synthesized by carbothermal reduction method.Based on the grown nanobelt with the length of 600μm...High qualityβ-Ga_(2)O_(3)single crystal nanobelts with length of 2−3 mm and width from tens of microns to 132μm were synthesized by carbothermal reduction method.Based on the grown nanobelt with the length of 600μm,the dual-Schottky-junctions coupling device(DSCD)was fabricated.Due to the electrically floating Ga_(2)O_(3)nanobelt region coupling with the double Schottky-junctions,the current I_(S2)increases firstly and rapidly reaches into saturation as increase the voltage V_(S2).The saturation current is about 10 pA,which is two orders of magnitude lower than that of a single Schottky-junction.In the case of solar-blind ultraviolet(UV)light irradiation,the photogenerated electrons further aggravate the coupling physical mechanism in device.I_(S2)increases as the intensity of UV light increases.Under the UV light of 1820μW/cm^(2),I_(S2)quickly enters the saturation state.At V_(S2)=10 V,photo-to-dark current ratio(PDCR)of the device reaches more than 104,the external quantum efficiency(EQE)is 1.6×10^(3)%,and the detectivity(D*)is 7.5×10^(12)Jones.In addition,the device has a very short rise and decay times of 25−54 ms under different positive and negative bias.DSCD shows unique electrical and optical control characteristics,which will open a new way for the application of nanobelt-based devices.展开更多
The atmospheric carbon dioxide(CO_(2))concentration has been increasing rapidly since the Industrial Revolution,which has led to unequivocal global warming and crucial environmental change.It is extremely important to...The atmospheric carbon dioxide(CO_(2))concentration has been increasing rapidly since the Industrial Revolution,which has led to unequivocal global warming and crucial environmental change.It is extremely important to investigate the interactions among atmospheric CO_(2),the physical climate system,and the carbon cycle of the underlying surface for a better understanding of the Earth system.Earth system models are widely used to investigate these interactions via coupled carbon-climate simulations.The Chinese Academy of Sciences Earth System Model version 2(CAS-ESM2.0)has successfully fixed a two-way coupling of atmospheric CO_(2)with the climate and carbon cycle on land and in the ocean.Using CAS-ESM2.0,we conducted a coupled carbon-climate simulation by following the CMIP6 proposal of a historical emissions-driven experiment.This paper examines the modeled CO_(2)by comparison with observed CO_(2)at the sites of Mauna Loa and Barrow,and the Greenhouse Gases Observing Satellite(GOSAT)CO_(2)product.The results showed that CAS-ESM2.0 agrees very well with observations in reproducing the increasing trend of annual CO_(2)during the period 1850-2014,and in capturing the seasonal cycle of CO_(2)at the two baseline sites,as well as over northern high latitudes.These agreements illustrate a good ability of CAS-ESM2.0 in simulating carbon-climate interactions,even though uncertainties remain in the processes involved.This paper reports an important stage of the development of CAS-ESM with the coupling of carbon and climate,which will provide significant scientific support for climate research and China’s goal of carbon neutrality.展开更多
Electrocatalytic reduction of CO_(2) converts intermittent renewable electricity into value-added liquid products with an enticing prospect,but its practical application is hampered due to the lack of high-performance...Electrocatalytic reduction of CO_(2) converts intermittent renewable electricity into value-added liquid products with an enticing prospect,but its practical application is hampered due to the lack of high-performance electrocatalysts.Herein,we elaborately design and develop strongly coupled nanosheets composed of Ag nanoparticles and Sn-SnO_(2) grains,designated as Ag/Sn-SnO_(2) nanosheets(NSs),which possess optimized electronic structure,high electrical conductivity,and more accessible sites.As a result,such a catalyst exhibits unprecedented catalytic performance toward CO_(2)-to-formate conversion with near-unity faradaic efficiency(≥90%),ultrahigh partial current density(2,000 mA cm^(−2)),and superior long-term stability(200 mA cm^(−2),200 h),surpassing the reported catalysts of CO_(2) electroreduction to formate.Additionally,in situ attenuated total reflection-infrared spectra combined with theoretical calculations revealed that electron-enriched Sn sites on Ag/Sn-SnO_(2)NSs not only promote the formation of*OCHO and alleviate the energy barriers of*OCHO to*HCOOH,but also impede the desorption of H*.Notably,the Ag/Sn-SnO_(2)NSs as the cathode in a membrane electrode assembly with porous solid electrolyte layer reactor can continuously produce~0.12 M pure HCOOH solution at 100 mA cm^(−2)over 200 h.This work may inspire further development of advanced electrocatalysts and innovative device systems for promoting practical application of producing liquid fuels from CO_(2).展开更多
A novel color image encryption scheme is developed to enhance the security of encryption without increasing the complexity. Firstly, the plain color image is decomposed into three grayscale plain images, which are con...A novel color image encryption scheme is developed to enhance the security of encryption without increasing the complexity. Firstly, the plain color image is decomposed into three grayscale plain images, which are converted into the frequency domain coefficient matrices(FDCM) with discrete cosine transform(DCT) operation. After that, a twodimensional(2D) coupled chaotic system is developed and used to generate one group of embedded matrices and another group of encryption matrices, respectively. The embedded matrices are integrated with the FDCM to fulfill the frequency domain encryption, and then the inverse DCT processing is implemented to recover the spatial domain signal. Eventually,under the function of the encryption matrices and the proposed diagonal scrambling algorithm, the final color ciphertext is obtained. The experimental results show that the proposed method can not only ensure efficient encryption but also satisfy various sizes of image encryption. Besides, it has better performance than other similar techniques in statistical feature analysis, such as key space, key sensitivity, anti-differential attack, information entropy, noise attack, etc.展开更多
Electrocatalytic CO_(2) reduction reaction(CO_(2)RR)holds great promise in green energy conversion and storage.However,for current CO_(2) electrolyzers that rely on the oxygen evolution reaction,a large portion of the...Electrocatalytic CO_(2) reduction reaction(CO_(2)RR)holds great promise in green energy conversion and storage.However,for current CO_(2) electrolyzers that rely on the oxygen evolution reaction,a large portion of the input energy is"wasted"at the anode due to the high overpotential requirement and the recovery of low-value oxygen.To make efficient use of the electricity during electrolysis,coupling CO_(2)RR with anodic alternatives that have low energy demands and/or profitable returns with high-value products is then promising.Herein,we review the latest advances in paired systems for simultaneous CO_(2) reduction and anode valorization.We start with the cases integrating CO_(2)RR with concurrent alternative oxidation,such as inorganic oxidation using chloride,sulfide,ammonia and urea,and organic oxidation using alcohols,aldehydes and primary amines.The paired systems that couple CO_(2)RR with on-site oxidative upgrading of CO_(2)-reduced chemicals are also introduced.The coupling mechanism,electrochemical performance and economic viability of these co-electrolysis systems are discussed.Thereby,we then point out the mismatch issues between the cathodic and anodic reactions regrading catalyst ability,electrolyte solution and reactant supply that will challenge the applications of these paired electrolysis systems.Opportunities to address these issues are further proposed,providing some guidance for future research.展开更多
To address the energy crisis and alleviate the rising level of CO_(2)in the atmosphere,various CO_(2)capture and utilization(CCU)technologies have been developed.The use of electro-enzyme coupling systems is a promisi...To address the energy crisis and alleviate the rising level of CO_(2)in the atmosphere,various CO_(2)capture and utilization(CCU)technologies have been developed.The use of electro-enzyme coupling systems is a promising strategy for the sustainable production of fuels,chemicals and materials using CO_(2)as the feedstock.In this review,the recent progresses in the development of electro-enzyme coupling systems for the selective reduction of CO_(2)are systematically summarized.We first provide a brief background about the significance and challenges in the direct conversion of CO_(2)into value-added chemicals.Next,we describe the materials and strategies in the design of electrodes,as well as the common enzymes used in the electro-enzyme coupling systems.Then,we focus on the state-of-the-art routes for the electro-enzyme coupling conversion of CO_(2)into a variety of compounds(formate,CO,methanol,C≥2chemicals)by a single enzyme or multienzyme systems.The emerging approaches and materials used for the construction of electro-enzyme coupling systems to enhance the electron transfer efficiency and the catalytic activity/stability are highlighted.The main challenges and perspectives in the integration of enzymatic and electrochemical strategies are also discussed.展开更多
We report the SERS enhancements of Raman forbidden surface modes of TiO<sub>2</sub> in different sized TiO<sub>2</sub> crystals. This current study utilizes the relationship between the vibroni...We report the SERS enhancements of Raman forbidden surface modes of TiO<sub>2</sub> in different sized TiO<sub>2</sub> crystals. This current study utilizes the relationship between the vibronic coupling and the degree of charge-transfer to explain the differences of Surface Enhanced Raman Scattering (SERS) enhancements. Our study shows a direct correlation between the degree of charge-transfer and vibronic coupling. This relationship suggests that charge-transfer between the N-719 dye and TiO<sub>2</sub> due to vibronic coupling plays a fundamental role in SERS enhancements. Furthermore, this study shows a strong dependence of the enhancements of the N-719 dye molecular modes to that of the surface modes. This indicates that the mechanism that governs the enhancements of the surface modes in TiO<sub>2</sub> crystals most likely also dictates the enhancements of the N-719 dyes.展开更多
Considering phase changes associated with a high-temperature molten material cooled down from the outside,this work presents an improvement of the modelling and the numerical simulation of such processes for an applic...Considering phase changes associated with a high-temperature molten material cooled down from the outside,this work presents an improvement of the modelling and the numerical simulation of such processes for an application pertaining to the safety of light water nuclear reactors.Postulating a core meltdown accident,the behaviour of the core melt(aka corium)into a steel vessel is of tremendous importance when evaluating the vessel integrity.Evaluating correctly the heat fluxes requires the numerical simulation of the interaction between the liquid material and its solid counterpart which forms during the solidification process,but also may melt back.To simulate this configuration,encoun-tered in various industrial applications,one considers a bi-phase model constituted by a liquid phase in contact and interaction with its solid phase.The liquid phase may solidify in presence of low energetic source,while the solid phase may melt due to an intense heat flux from the high-temperature liquid.In the frame of the in-house legacy code,several simplifying assumptions(0D multi-layer discretization,instantaneous heat transfer via a quadratic temperature profile in solids)are made for the modelling of such phase changes.In the present work,these shortcomings are illustrated and further overcome by solving a 2D heat conduction model in the solid by a mixed Raviart-Thomas finite element method coupled to the liquid phase due to heat and mass exchanges through Stefan condition.The liquid phase is modeled with a 0D multi-layer approach.The 0D-liquid and 2D-solid mod-els are coupled by a Stefan like phase change interface model.Several sanity checks are performed to assess the validity of the approach on 1D and 2D academical configurations for which exact or reference solutions are available.Then more advanced situations(genu-ine multi-dimensional phase changes and an"industrial-like scenario")are simulated to verify the appropriate behavior of the obtained coupled simulation scheme.展开更多
The electrocatalytic CO_(2) reduction in aqueous solution mainly involves bond cleavage and formation between C,H and O,and it is highly desirable to expand the bond formation reaction of C with other atoms to obtain ...The electrocatalytic CO_(2) reduction in aqueous solution mainly involves bond cleavage and formation between C,H and O,and it is highly desirable to expand the bond formation reaction of C with other atoms to obtain novel and valuable chemicals.The electrochemical synthesis of N-containing organic chemicals in electrocatalytic CO_(2) reduction via introducing N sources is an effective strategy to expand the product scope,since chemicals con-taining C–N bonds(e.g.amides and amines)are important reactants/products for medicine,agriculture and in-dustry.This article focuses on the research progress of C–N coupling from CO_(2) and inorganic nitrogenous species in aqueous solution.Firstly,the reaction pathways related to the reaction intermediates for urea,formamide,acetamide,methylamine and ethylamine are highlighted.Then,the electrocatalytic performance of different catalysts for these several N-containing products are summarized and classified.Finally,the challenges and op-portunities are analyzed,aiming to provide general insights into future research directions for electrocatalytic C–N coupling.展开更多
The elastic and functional coupling of heart and vessels makes the stroke work (SW) of the heart optimal. Speckle tracking imaging (STI) can evaluate the myocardial strain and function. We studied ventricular-vasc...The elastic and functional coupling of heart and vessels makes the stroke work (SW) of the heart optimal. Speckle tracking imaging (STI) can evaluate the myocardial strain and function. We studied ventricular-vascular coupling in 80 diabetic patients with different systolic function using STI. The patients were divided into two groups according to ejection fraction (EF): the diabetes mel- litus with normal EF (DMN) group and the diabetes mellitus with abnormal EF (DMA) group. Forty-two volunteers served as control group. The relative wall thickness (RWT), left ventricular mass index (LVMI), stroke volume (SV), SW, rate-pressure product (RPP), systemic vascular resis- tance index (SVRI), left ventricular end-systolic elastance (Ees), effective arterial elasticity (Ea) and ventricular-vascular coupling index (VVI) were measured and calculated by conventional echocardi- ography. The longitudinal strain (LS) at basement (LSBA), papillary muscle (LSvM) and cardiac apex (LSAv) was assessed with STI. It was found: (A) compared with control group, in DMN and DMA groups, LSBA, LSvM and LSAp decreased, and they were lower in DMA group. (B) VVI, RPP and SVRI increased, and they were higher in DMN group; Ees decreased, and it was lower in DMA group. (C) LSBA, LSpM, and LSAv had negative correlation with VVI. LSAp, RWT, LVMI and SW were independent predictors for VVI. The area under the receiver operating characteristic (ROC) curves was used for identification of DMA and DMN with LSBA, LSpM, and LSAp, and the area under the ROC of LSAp was the largest. This study supports that myocardial LS could reflect the ventricu- lar-vascular coupling. Different segments had an order to “respond to” the state of the coupling, and the cardiac apex might be the earliest.展开更多
基金support from the Tangshan Talent Funding Project(Grant No.A202202007)National Natural Science Foundation of China(Grant Nos.22102136 and 21703065)+2 种基金Natural Science Foundation of Hebei Province(Grant Nos.B2018209267 and E2022209039)Natural Science Foundation of Hubei Province(Grant No.2022CFB1001)Department of Education of Hubei Province(Grant No.Q20221701).
文摘Electrochemical C-C and C-N coupling reactions with the conversion of abundant and inexpensive small molecules,such as CO_(2) and nitrogencontaining species,are considered a promising route for increasing the value of CO_(2) reduction products.The development of high-performance catalysts is the key to the both electrocatalytic reactions.In this review,we present a systematic summary of the reaction systems for electrocatalytic CO_(2) reduction,along with the coupling mechanisms of C-C and C-N bonds over outstanding electrocatalytic materials recently developed.The key intermediate species and reaction pathways related to the coupling as well as the catalyst-structure relationship will be also discussed,aiming to provide insights and guidance for designing efficient CO_(2) reduction systems.
基金the National Natural Science Foundation of China(51303083)the National Natural Science Foundation of China for Excellent Young Scholars(51922050)+1 种基金the Natural Science Foundation of Jiangsu Province(BK20191293)the Fundamental Research Funds for the Central Universities(30920021123)。
文摘Photothermal catalytic CO_(2) conversion provides an effective solution targeting carbon neutrality by synergistic utilization of photon and heat.However,the C-C coupling initiated by photothermal catalysis is still a big challenge.Herein,a three-dimensional(3D)hierarchical W_(18)O_(49)/WTe_(2) hollow nanosphere is constructed through in-situ embodying of oxygen vacancy and tellurium on the scaffold of WO_(3).The light absorption towards near-infrared spectral region and CO_(2) adsorption are enhanced by the formation of half-metal WTe_(2) and the unique hierarchical hollow architecture.Combining with the generation of oxygen vacancy with strengthened CO_(2) capture,the photothermal effect on the samples can be sufficiently exploited for activating the CO_(2) molecules.In particular,the close contact between W_(18)O_(49)and WTe_(2) largely promotes the photoinduced charge separation and mass transfer,and thus the~*CHO intermediate formation and fixedness are facilitated.As a result,the C-C coupling can be evoked between tungsten and tellurium atoms on WTe_(2).The ethylene production by optimized W_(18)O_(49)/WTe_(2) reaches 147.6μmol g^(-1)with the selectivity of 80%.The in-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)and density functional theory(DFT)calculations are performed to unveil the presence and significance of aldehyde intermediate groups in C-C coupling.The half-metallic WTe_(2) cocatalyst proposes a new approach for efficient CO_(2) conversion with solar energy,and may especially create a new platform for the generation of multi-carbon products.
基金supported by the National Natural Science Foundation of China(52072196,52002200,52102106,52202262,22379081,22379080)the Major Basic Research Program of Natural Science Foundation of Shandong Province(ZR2020ZD09)+1 种基金the Natural Science Foundation of Shandong Province(ZR2020QE063,ZR202108180009,ZR2023QE059)the Project funded by China Postdoctoral Science Foundation(2023M741871)。
文摘Steering the directional carrier migration across the interface is a central mission for efficient photocatalytic reactions.In this work,an atomic-shared heterointerface is constructed between the defect-rich ZnIn_(2)S_(4)(HVs-ZIS)and CoIn_(2)S_(4)(CIS)via a defect-guided heteroepitaxial growth strategy.The strong interface coupling induces adequate carriers exchanging passageway between HVs-ZIS and CIS,enhancing the internal electric field(IEF)in the ZnIn_(2)S_(4)/CoIn_(2)S_(4)(HVs-ZIS/CIS)heterostructure.The defect structure in HVs-ZIS induces an additional defect level,improving the separation efficiency of photocarriers.Moreover,promoted by the IEF and intimate heterointerface,photogenerated electrons trapped by the defect level can migrate to the valence band of CIS,contributing to massive photogenerated electrons with intense reducibility in HVs-ZIS/CIS.Consequently,the HVs-ZIS/CIS heterostructure performs a boosted H_(2)evolution activity of 33.65 mmol g^(-1)h^(-1).This work highlights the synergistic effects of defect and strong interface coupling in regulating carrier transfer and paves a brave avenue for constructing efficient heterostructure photocatalysts.
基金supported by Natural Science Basic Research Program in Shaanxi Province of China(No.2023-JCYB-574)National Natural Science Foundation of China(No.62204203).
文摘High qualityβ-Ga_(2)O_(3)single crystal nanobelts with length of 2−3 mm and width from tens of microns to 132μm were synthesized by carbothermal reduction method.Based on the grown nanobelt with the length of 600μm,the dual-Schottky-junctions coupling device(DSCD)was fabricated.Due to the electrically floating Ga_(2)O_(3)nanobelt region coupling with the double Schottky-junctions,the current I_(S2)increases firstly and rapidly reaches into saturation as increase the voltage V_(S2).The saturation current is about 10 pA,which is two orders of magnitude lower than that of a single Schottky-junction.In the case of solar-blind ultraviolet(UV)light irradiation,the photogenerated electrons further aggravate the coupling physical mechanism in device.I_(S2)increases as the intensity of UV light increases.Under the UV light of 1820μW/cm^(2),I_(S2)quickly enters the saturation state.At V_(S2)=10 V,photo-to-dark current ratio(PDCR)of the device reaches more than 104,the external quantum efficiency(EQE)is 1.6×10^(3)%,and the detectivity(D*)is 7.5×10^(12)Jones.In addition,the device has a very short rise and decay times of 25−54 ms under different positive and negative bias.DSCD shows unique electrical and optical control characteristics,which will open a new way for the application of nanobelt-based devices.
基金the National Key Research and Development Program of China(Grant No.2022YFE0106500)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Grant No.2022076)+1 种基金the National Key Scientific and Technological Infrastructure project“Earth System Numerical Simulation Facility”(EarthLab2023-EL-ZD-00012)。
文摘The atmospheric carbon dioxide(CO_(2))concentration has been increasing rapidly since the Industrial Revolution,which has led to unequivocal global warming and crucial environmental change.It is extremely important to investigate the interactions among atmospheric CO_(2),the physical climate system,and the carbon cycle of the underlying surface for a better understanding of the Earth system.Earth system models are widely used to investigate these interactions via coupled carbon-climate simulations.The Chinese Academy of Sciences Earth System Model version 2(CAS-ESM2.0)has successfully fixed a two-way coupling of atmospheric CO_(2)with the climate and carbon cycle on land and in the ocean.Using CAS-ESM2.0,we conducted a coupled carbon-climate simulation by following the CMIP6 proposal of a historical emissions-driven experiment.This paper examines the modeled CO_(2)by comparison with observed CO_(2)at the sites of Mauna Loa and Barrow,and the Greenhouse Gases Observing Satellite(GOSAT)CO_(2)product.The results showed that CAS-ESM2.0 agrees very well with observations in reproducing the increasing trend of annual CO_(2)during the period 1850-2014,and in capturing the seasonal cycle of CO_(2)at the two baseline sites,as well as over northern high latitudes.These agreements illustrate a good ability of CAS-ESM2.0 in simulating carbon-climate interactions,even though uncertainties remain in the processes involved.This paper reports an important stage of the development of CAS-ESM with the coupling of carbon and climate,which will provide significant scientific support for climate research and China’s goal of carbon neutrality.
基金the National Science Fund for Distinguished Young Scholars(Grant No.52125103)the National Natural Science Foundation of China(Grant Nos.52301232,52071041,12074048,and 12147102)China Postdoctoral Science Foundation(Grant No.2022M720552).
文摘Electrocatalytic reduction of CO_(2) converts intermittent renewable electricity into value-added liquid products with an enticing prospect,but its practical application is hampered due to the lack of high-performance electrocatalysts.Herein,we elaborately design and develop strongly coupled nanosheets composed of Ag nanoparticles and Sn-SnO_(2) grains,designated as Ag/Sn-SnO_(2) nanosheets(NSs),which possess optimized electronic structure,high electrical conductivity,and more accessible sites.As a result,such a catalyst exhibits unprecedented catalytic performance toward CO_(2)-to-formate conversion with near-unity faradaic efficiency(≥90%),ultrahigh partial current density(2,000 mA cm^(−2)),and superior long-term stability(200 mA cm^(−2),200 h),surpassing the reported catalysts of CO_(2) electroreduction to formate.Additionally,in situ attenuated total reflection-infrared spectra combined with theoretical calculations revealed that electron-enriched Sn sites on Ag/Sn-SnO_(2)NSs not only promote the formation of*OCHO and alleviate the energy barriers of*OCHO to*HCOOH,but also impede the desorption of H*.Notably,the Ag/Sn-SnO_(2)NSs as the cathode in a membrane electrode assembly with porous solid electrolyte layer reactor can continuously produce~0.12 M pure HCOOH solution at 100 mA cm^(−2)over 200 h.This work may inspire further development of advanced electrocatalysts and innovative device systems for promoting practical application of producing liquid fuels from CO_(2).
基金Project supported by the National Natural Science Foundation of China(Grant Nos.62105004 and 52174141)the College Student Innovation and Entrepreneurship Fund Project(Grant No.202210361053)+1 种基金Anhui Mining Machinery and Electrical Equipment Coordination Innovation Center,Anhui University of Science&Technology(Grant No.KSJD202304)the Anhui Province Digital Agricultural Engineering Technology Research Center Open Project(Grant No.AHSZNYGC-ZXKF021)。
文摘A novel color image encryption scheme is developed to enhance the security of encryption without increasing the complexity. Firstly, the plain color image is decomposed into three grayscale plain images, which are converted into the frequency domain coefficient matrices(FDCM) with discrete cosine transform(DCT) operation. After that, a twodimensional(2D) coupled chaotic system is developed and used to generate one group of embedded matrices and another group of encryption matrices, respectively. The embedded matrices are integrated with the FDCM to fulfill the frequency domain encryption, and then the inverse DCT processing is implemented to recover the spatial domain signal. Eventually,under the function of the encryption matrices and the proposed diagonal scrambling algorithm, the final color ciphertext is obtained. The experimental results show that the proposed method can not only ensure efficient encryption but also satisfy various sizes of image encryption. Besides, it has better performance than other similar techniques in statistical feature analysis, such as key space, key sensitivity, anti-differential attack, information entropy, noise attack, etc.
基金financially supported by the National Natural Science Foundation of China(22002084,22072081)the China Postdoctoral Science Foundation(2020M683420)+1 种基金the Fundamental Research Funds for the Central Universities(GK202103111)the 111 Project(B21005)。
文摘Electrocatalytic CO_(2) reduction reaction(CO_(2)RR)holds great promise in green energy conversion and storage.However,for current CO_(2) electrolyzers that rely on the oxygen evolution reaction,a large portion of the input energy is"wasted"at the anode due to the high overpotential requirement and the recovery of low-value oxygen.To make efficient use of the electricity during electrolysis,coupling CO_(2)RR with anodic alternatives that have low energy demands and/or profitable returns with high-value products is then promising.Herein,we review the latest advances in paired systems for simultaneous CO_(2) reduction and anode valorization.We start with the cases integrating CO_(2)RR with concurrent alternative oxidation,such as inorganic oxidation using chloride,sulfide,ammonia and urea,and organic oxidation using alcohols,aldehydes and primary amines.The paired systems that couple CO_(2)RR with on-site oxidative upgrading of CO_(2)-reduced chemicals are also introduced.The coupling mechanism,electrochemical performance and economic viability of these co-electrolysis systems are discussed.Thereby,we then point out the mismatch issues between the cathodic and anodic reactions regrading catalyst ability,electrolyte solution and reactant supply that will challenge the applications of these paired electrolysis systems.Opportunities to address these issues are further proposed,providing some guidance for future research.
基金the financial supports from the National Key R&D Program of China(2022YFC2105900)National Natural Science Foundation of China(22122801,U22A20426)。
文摘To address the energy crisis and alleviate the rising level of CO_(2)in the atmosphere,various CO_(2)capture and utilization(CCU)technologies have been developed.The use of electro-enzyme coupling systems is a promising strategy for the sustainable production of fuels,chemicals and materials using CO_(2)as the feedstock.In this review,the recent progresses in the development of electro-enzyme coupling systems for the selective reduction of CO_(2)are systematically summarized.We first provide a brief background about the significance and challenges in the direct conversion of CO_(2)into value-added chemicals.Next,we describe the materials and strategies in the design of electrodes,as well as the common enzymes used in the electro-enzyme coupling systems.Then,we focus on the state-of-the-art routes for the electro-enzyme coupling conversion of CO_(2)into a variety of compounds(formate,CO,methanol,C≥2chemicals)by a single enzyme or multienzyme systems.The emerging approaches and materials used for the construction of electro-enzyme coupling systems to enhance the electron transfer efficiency and the catalytic activity/stability are highlighted.The main challenges and perspectives in the integration of enzymatic and electrochemical strategies are also discussed.
文摘We report the SERS enhancements of Raman forbidden surface modes of TiO<sub>2</sub> in different sized TiO<sub>2</sub> crystals. This current study utilizes the relationship between the vibronic coupling and the degree of charge-transfer to explain the differences of Surface Enhanced Raman Scattering (SERS) enhancements. Our study shows a direct correlation between the degree of charge-transfer and vibronic coupling. This relationship suggests that charge-transfer between the N-719 dye and TiO<sub>2</sub> due to vibronic coupling plays a fundamental role in SERS enhancements. Furthermore, this study shows a strong dependence of the enhancements of the N-719 dye molecular modes to that of the surface modes. This indicates that the mechanism that governs the enhancements of the surface modes in TiO<sub>2</sub> crystals most likely also dictates the enhancements of the N-719 dyes.
基金funded by CEA,EDF and Framatomefinancial and scientific support of CEA Cadarache.
文摘Considering phase changes associated with a high-temperature molten material cooled down from the outside,this work presents an improvement of the modelling and the numerical simulation of such processes for an application pertaining to the safety of light water nuclear reactors.Postulating a core meltdown accident,the behaviour of the core melt(aka corium)into a steel vessel is of tremendous importance when evaluating the vessel integrity.Evaluating correctly the heat fluxes requires the numerical simulation of the interaction between the liquid material and its solid counterpart which forms during the solidification process,but also may melt back.To simulate this configuration,encoun-tered in various industrial applications,one considers a bi-phase model constituted by a liquid phase in contact and interaction with its solid phase.The liquid phase may solidify in presence of low energetic source,while the solid phase may melt due to an intense heat flux from the high-temperature liquid.In the frame of the in-house legacy code,several simplifying assumptions(0D multi-layer discretization,instantaneous heat transfer via a quadratic temperature profile in solids)are made for the modelling of such phase changes.In the present work,these shortcomings are illustrated and further overcome by solving a 2D heat conduction model in the solid by a mixed Raviart-Thomas finite element method coupled to the liquid phase due to heat and mass exchanges through Stefan condition.The liquid phase is modeled with a 0D multi-layer approach.The 0D-liquid and 2D-solid mod-els are coupled by a Stefan like phase change interface model.Several sanity checks are performed to assess the validity of the approach on 1D and 2D academical configurations for which exact or reference solutions are available.Then more advanced situations(genu-ine multi-dimensional phase changes and an"industrial-like scenario")are simulated to verify the appropriate behavior of the obtained coupled simulation scheme.
基金financially supported by National Natural Science Foundation of China(22072051,22122202,21972051).
文摘The electrocatalytic CO_(2) reduction in aqueous solution mainly involves bond cleavage and formation between C,H and O,and it is highly desirable to expand the bond formation reaction of C with other atoms to obtain novel and valuable chemicals.The electrochemical synthesis of N-containing organic chemicals in electrocatalytic CO_(2) reduction via introducing N sources is an effective strategy to expand the product scope,since chemicals con-taining C–N bonds(e.g.amides and amines)are important reactants/products for medicine,agriculture and in-dustry.This article focuses on the research progress of C–N coupling from CO_(2) and inorganic nitrogenous species in aqueous solution.Firstly,the reaction pathways related to the reaction intermediates for urea,formamide,acetamide,methylamine and ethylamine are highlighted.Then,the electrocatalytic performance of different catalysts for these several N-containing products are summarized and classified.Finally,the challenges and op-portunities are analyzed,aiming to provide general insights into future research directions for electrocatalytic C–N coupling.
基金supported by a grant from the Shanghai Health and Family Planning Commission,China(No.201440290)
文摘The elastic and functional coupling of heart and vessels makes the stroke work (SW) of the heart optimal. Speckle tracking imaging (STI) can evaluate the myocardial strain and function. We studied ventricular-vascular coupling in 80 diabetic patients with different systolic function using STI. The patients were divided into two groups according to ejection fraction (EF): the diabetes mel- litus with normal EF (DMN) group and the diabetes mellitus with abnormal EF (DMA) group. Forty-two volunteers served as control group. The relative wall thickness (RWT), left ventricular mass index (LVMI), stroke volume (SV), SW, rate-pressure product (RPP), systemic vascular resis- tance index (SVRI), left ventricular end-systolic elastance (Ees), effective arterial elasticity (Ea) and ventricular-vascular coupling index (VVI) were measured and calculated by conventional echocardi- ography. The longitudinal strain (LS) at basement (LSBA), papillary muscle (LSvM) and cardiac apex (LSAv) was assessed with STI. It was found: (A) compared with control group, in DMN and DMA groups, LSBA, LSvM and LSAp decreased, and they were lower in DMA group. (B) VVI, RPP and SVRI increased, and they were higher in DMN group; Ees decreased, and it was lower in DMA group. (C) LSBA, LSpM, and LSAv had negative correlation with VVI. LSAp, RWT, LVMI and SW were independent predictors for VVI. The area under the receiver operating characteristic (ROC) curves was used for identification of DMA and DMN with LSBA, LSpM, and LSAp, and the area under the ROC of LSAp was the largest. This study supports that myocardial LS could reflect the ventricu- lar-vascular coupling. Different segments had an order to “respond to” the state of the coupling, and the cardiac apex might be the earliest.