Sodium-ion batteries(SIBs)have attracted significant attention in large-scale energy storage system because of their abundant sodium resource and cost-effectiveness.Layered oxide materials are particularly promising a...Sodium-ion batteries(SIBs)have attracted significant attention in large-scale energy storage system because of their abundant sodium resource and cost-effectiveness.Layered oxide materials are particularly promising as SIBs cathodes due to their high theoretical capacities and facile synthesis.However,their practical applications are hindered by the limitations in energy density and cycling stability.The comprehensive understanding of failure mechanisms within bulk structure and at the cathode/electrolyte interface of cathodes is still lacking.In this review,the issues related to bulk phase degradation and surface degradation,such as irreversible phase transitions,cation migration,transition metal dissolution,air/moisture instability,intergranular cracking,interfacial reactions,and reactive oxygen loss,are discussed.The latest advances and strategies to improve the stability of layered oxide cathodes and full cells are provided,as well as our perspectives on the future development of SIBs.展开更多
This paper addresses the lane-keeping control problem for autonomous ground vehicles subject to input saturation and uncertain system parameters.An enhanced adaptive terminal sliding mode based prescribed performance ...This paper addresses the lane-keeping control problem for autonomous ground vehicles subject to input saturation and uncertain system parameters.An enhanced adaptive terminal sliding mode based prescribed performance control scheme is proposed,which enables the lateral position error of the vehicle to be kept within the prescribed performance boundaries all the time.This is achieved by firstly introducing an improved performance function into the controller design such that the stringent initial condition requirements can be relaxed,which further allows the global prescribed performance control result,and then,developing a multivariable adaptive terminal sliding mode based controller such that both input saturation and parameter uncertainties are handled effectively,which further ensures the robust lane-keeping control.Finally,the proposed control strategy is validated through numerical simulations,demonstrating its effectiveness.展开更多
Photothermal catalysis represents an emerging technology for solar energy conversion that combines the principles and advantages of photoand thermal catalytic mechanisms[1–5].Driven by the inter/intra-band transition...Photothermal catalysis represents an emerging technology for solar energy conversion that combines the principles and advantages of photoand thermal catalytic mechanisms[1–5].Driven by the inter/intra-band transitions and subsequent electron-phonon scattering processes,photothermal catalysts can achieve rapid and highly localized heating,providing thermal activation to the chemical conversions.Besides,direct participation of photo-generated charge carriers could also drastically reduce the activation energy barriers and modulate the catalytic pathways.However,distinction between thermal and non-thermal contributions remains a key challenge for both fundamental understandings and large-scale applications of photothermal catalysis[6,7].This issue is largely due to a lack of precise in-situ surface-temperature measurement techniques that accurately quantify the light-to-heat conversion under reaction conditions at the nanoscale.Conventional macroscopic temperature measurement techniques,such as infrared cameras and thermocouples,suffer from the lack of spatiotemporal resolutions required for the localized photothermal conversion.They are,thus,measuring an average temperature of the ambient medium.Besides,they typically cannot be applied in in-situ temperature measurements,which is crucial since inaccurate heat dissipation rates may be predicted by ex-situ temperature measurement techniques.For instance,differences in gas pressure,composition and flow rate could lead to significantly different convective heat fluxes.展开更多
This study aimed to establish a closed-cycle operation technology with high thermal efficiency in the thermochemical sulfur-iodine cycle for large-scale hydrogen production.A series of experimental studies were perfor...This study aimed to establish a closed-cycle operation technology with high thermal efficiency in the thermochemical sulfur-iodine cycle for large-scale hydrogen production.A series of experimental studies were performed to investigate the occurrence of side reactions in both the H2SO4 and HI x phases from the H2SO4/HI/I2/H2O quaternary system within a constant temperature range of 323-363 K.The effects of iodine content,water content and reaction temperature on the side reactions were evaluated.The results showed that an increase in the reaction temperature promoted the side reactions.However,they were prevented as the iodine or water content increased.The occurrence of side reactions was faster in kinetics and more intense in the H2SO4 phase than in the HI x phase.The sulfur or hydrogen sulfide formation reaction or the reverse Bunsen reaction was validated under certain conditions.展开更多
Myanmar is located in Southeast Asia within the Mekong River Basin. The estimated annual surface and groundwater potentials are 1 081 km^3 and 494 km^3, respectively. Based on geological conditions, 11 different types...Myanmar is located in Southeast Asia within the Mekong River Basin. The estimated annual surface and groundwater potentials are 1 081 km^3 and 494 km^3, respectively. Based on geological conditions, 11 different types of aquifers have been classified in Myanmar. The recent alluvial formation, Irrawaddy formation, Upper Pegu Group and Plateau limestone formation are the major water-bearing geologic formations of the country. In Myanmar, 89% of the groundwater is used for agriculture, approximately 8% is used for domestic consumption, and 3% is used for industrial purposes. Climate change projections for Myanmar from 2001 to 2100 predict general increases in temperature, clear-sky days, rainfall variability and flooding risks and a greater occurrence and intensity of extreme weather events across the country. Additional technology and investments are required to achieve groundwater resource security in response to climate changes. In addition, methods of ensuring the sustainability of groundwater resources must be implemented via collaborations with other countries and international sources.展开更多
The two-phase flow maldistribution phenomenon in microchannels with multi-parallel branches is inevitable in almost all common conditions,and not only affects the performance of the facility but also increases the ris...The two-phase flow maldistribution phenomenon in microchannels with multi-parallel branches is inevitable in almost all common conditions,and not only affects the performance of the facility but also increases the risk of system instability.In order to better understand the distribution mechanism and to explore a potential strategy to improve uniformity,the pressure evolutions under different split modes in a microchannel with multi-parallel branches,were analyzed numerically.The results show that the fluctuations of transient pressure exhibit similar trends at various split modes,but the time-averaged pressure drops in the branches are very different.This may be related to the maldistribution of mass flow.Thus,the outlet pressures of the branches are numerically changed to explore the relationship between differential pressure and flow distribution.From this study,the flow distribution is seen to display a strong sensitivity to the branch differential pressure.By changing the pressure conditions,the gas flow of the middle branch can be effectively prevented from the main channel,and the flow type in this branch turns from gas-liquid to a single liquid phase.When the differential pressure of the first branch channel changes,the maldistribution phenomenon of the model can be mitigated to a certain extent.Based on this,by adjusting the differential pressures of the second branch,the maldistribution phenomenon can be further mitigated,and the normalized standard deviation(NSTD)decreases from 0.52 to approximately 0.26.The results and conclusions are useful in understanding the two-phase flow distribution mechanism and for seeking optimizing strategies.展开更多
Powdery mildew, caused by Blumeria graminis f. sp. tritici, is one of the most devastating wheat diseases. Wild emmer wheat（Triticum turgidum ssp. dicoccoides） is a promising source of disease resistance for wheat. ...Powdery mildew, caused by Blumeria graminis f. sp. tritici, is one of the most devastating wheat diseases. Wild emmer wheat（Triticum turgidum ssp. dicoccoides） is a promising source of disease resistance for wheat. A powdery mildew resistance gene conferring resistance to B. graminis f. sp. tritici isolate E09, originating from wild emmer wheat, has been transferred into the hexaploid wheat line WE4 through crossing and backcrossing. Genetic analyses indicated that the powdery mildew resistance was controlled by a single dominant gene, temporarily designated Ml WE4. By mean of comparative genomics and bulked segregant analysis, a genetic linkage map of Ml WE4 was constructed, and Ml WE4 was mapped on the distal region of chromosome arm 5BL. Comparative genetic linkage maps showed that genes Ml WE4, Pm36 and Ml3D232 were co-segregated with markers XBD37670 and XBD37680, indicating they are likely the same gene or alleles in the same locus. The co-segregated markers provide a starting point for chromosome landing and map-based cloning of Ml WE4, Pm36 and Ml3D232.展开更多
The Global Geopotential Models (GGMs) of GOCE (Gravity Recovery and steady- state Ocean Circulation Explorer) differ globally as well as regionally in their accuracy and resolution based on the maximum degree and orde...The Global Geopotential Models (GGMs) of GOCE (Gravity Recovery and steady- state Ocean Circulation Explorer) differ globally as well as regionally in their accuracy and resolution based on the maximum degree and order (d/o) of the fully normalized spherical harmonic (SH) coefficients, which express each GGM. The main idea of this study is to compare the free-air gravity anomalies and quasi geoid heights determined from several recent GOCE-based GGMs with the corresponding ones from the Earth Gravitational Model 2008 (EGM2008) over Egypt on the one hand and with ground-based measurements on the other hand. The results regarding to the comparison of GOCE-based GGMs with terrestrial gravity and GPS/levelling data provide better improvement with respect to EGM2008. The 4th release GOCE-based GGM developed with the use of space-wise solution strategy (SPW_R4) approximates the gravity field well over the Egyptian region. The SPW_R4 model is accordingly suggested as a reference model for recovering the long wavelength (up to SH d/o 200) components of quasi geoid heights when modelling the gravimetric quasi-geoid over the Egypt. Finally, three types of transformation models: Four-, Five- and Seven-parameter transformations have been applied to reduce the data biases and to provide a better fitting of quasi geoid heights obtained from the studied GOCE-based GGMs to those from GPS/levelling data. These models reveal that the standard deviation of vertical datum over Egypt is at the level of about 32 cm.展开更多
The gravity field and steady-state ocean circulation explorer (GOCE) satellite mission has provided numerous Global Geopotential Models (GGMs) with different processing methodologies and model accuracies. In the curre...The gravity field and steady-state ocean circulation explorer (GOCE) satellite mission has provided numerous Global Geopotential Models (GGMs) with different processing methodologies and model accuracies. In the current contribution, the latest releases of GOCE-based GGMs are evaluated on the regional scale using the available terrestrial GPS/Levelling and gravity data collected over Egypt. To overcome the spectral inconsistency between the GOCE-based GGMs and the ground-based data, the spectral enhancement method (SEM) is applied. Five of GOCE-based GGMs have been used, namely GOSG01S, IGGT_R1, IfE_GOCE05s_ GO_CONS_GCF_2_SPW_R5 (SPW_R5 in the following) and NULP-02. The evaluation process of GOCE-based GGMs with the available ground data over Egypt considering the SEM method shows remarkable improvements obtained from the SPW_R5 model. The model provides lower differences of the standard deviations with respect to the EGM2008 and the other applied geopotential gravity models as well as the applied ground-based gravity and GPS/Levelling data. The findings regarding the ground-based data show obvious reductions of about 15.16% and 32.22% achieved by the GOCE-based model in term of standard deviations differences of gravity anomalies and geoid heights, respectively. Therefore, the SPW_R5 model is recommended to be applied as a reference model for compensating the long-to-short wavelength (up to spherical harmonics degree/order 280) components when modelling the gravimetric geoid over Egypt.展开更多
This paper presents a closed-loop vector control structure based on adaptive Fuzzy Logic Sliding Mode Controller (FL-SMC) for a grid-connected Wave Energy Conversion System (WECS) driven Self-Excited Induction Generat...This paper presents a closed-loop vector control structure based on adaptive Fuzzy Logic Sliding Mode Controller (FL-SMC) for a grid-connected Wave Energy Conversion System (WECS) driven Self-Excited Induction Generator (SEIG). The aim of the developed control method is to automatically tune and optimize the scaling factors and the membership functions of the Fuzzy Logic Controllers (FLC) using Multi-Objective Genetic Algorithms (MOGA) and Multi-Objective Particle Swarm Optimization (MOPSO). Two Pulse Width Modulated voltage source PWM converters with a carrier-based Sinusoidal PWM modulation for both Generator- and Grid-side converters have been connected back to back between the generator terminals and utility grid via common DC link. The indirect vector control scheme is implemented to maintain balance between generated power and power supplied to the grid and maintain the terminal voltage of the generator and the DC bus voltage constant for variable rotor speed and load. Simulation study has been carried out using the MATLAB/Simulink environment to verify the robustness of the power electronics converters and the effectiveness of proposed control method under steady state and transient conditions and also machine parameters mismatches. The proposed control scheme has improved the voltage regulation and the transient performance of the wave energy scheme over a wide range of operating conditions.展开更多
Oxy-combustion is a promising carbon-capture technology,but atmospheric-pressure oxy-combustion has a relatively low net efficiency,limiting its application in power plants.In pressurized oxycombustion(POC),the boiler...Oxy-combustion is a promising carbon-capture technology,but atmospheric-pressure oxy-combustion has a relatively low net efficiency,limiting its application in power plants.In pressurized oxycombustion(POC),the boiler,air separation unit,flue gas recirculation unit,and CO_(2)purification and compression unit are all operated at elevated pressure;this makes the process more efficient,with many advantages over atmospheric pressure,such as low NO_(x)emissions,a smaller boiler size,and more.POC is also more promising for industrial application and has attracted widespread research interest in recent years.It can produce high-pressure CO_(2)with a purity of approximately 95%,which can be used directly for enhanced oil recovery or geo-sequestration.However,the pollutant emissions must meet the standards for carbon capture,storage,and utilization.Because of the high oxygen and moisture concentrations in POC,the formation of acids via the oxidation and solution of SO_(x)and NO_(x)can be increased,causing the corrosion of pipelines and equipment.Furthermore,particulate matter(PM)and mercury emissions can harm the environment and human health.The main distinction between pressurized and atmospheric-pressure oxy-combustion is the former’s elevated pressure;thus,the effect of this pressure on the pollutants emitted from POC—including SO_(x),NO_(x),PM,and mercury—must be understood,and effective control methodologies must be incorporated to control the formation of these pollutants.This paper reviews recent advances in research on SO_(x),NO_(x),PM,and mercury formation and control in POC systems that can aid in pollutant control in such systems.展开更多
Abstract Cuticular wax covers the surface of the apple epidermis and plays an important role in water loss and pathogen resistance.However,little is known about wax biosynthesis during apple fruit development.In this ...Abstract Cuticular wax covers the surface of the apple epidermis and plays an important role in water loss and pathogen resistance.However,little is known about wax biosynthesis during apple fruit development.In this study,the morphological structure and chemical composition of wax and the transcription patterns of wax-related genes were investigated in the'Red Delicious'and'Golden Delicious'cultivars.The results showed that accumulation of the waxy layer was synchronized with enlargement and maturation of fruit.The crystal structure,major chemical components(very long chain fatty acids and triterpenes)of wax and the expression levels of wax-related genes varied significantly 90 days after flowering(DAF),indicating that the critical period for biosynthesis of cuticular wax was about 90 DAF.This finding is valuable for further study of the regulatory mechanism of wax biosynthesis at both the molecular and physiological levels.展开更多
Leaf senescence plays an important role in crop developmental processes that dramatically affect crop yield and grain quality. The genetic regulation of leaf senescence is complex, involving many metabolic and signali...Leaf senescence plays an important role in crop developmental processes that dramatically affect crop yield and grain quality. The genetic regulation of leaf senescence is complex, involving many metabolic and signaling pathways. Here, we identified a rapid leaf senescence 3 （rls3） mutant that displayed accelerated leaf senescence, shorter plant height and panicle length, and lower seed set rate than the wild type. Map-based cloning revealed that RLS3 encodes a protein with AAA＋ domain, localizing it to chloroplasts. Sequence analysis found that the rls3 8ene had a single-nucleotide substitution （G--~A） at the splice site of the Ioth intron/11th exon, resulting in the cleavage of the first nucleotide in 11th exon and premature termination of P, LS3 protein translation. Using transmission electron microscope, the chloroplasts of the rls3 mutant were observed to degrade much faster than those of the wild type. The investigation of the leaf senescence process under dark incubation conditions further revealed that the rls3 mutant displayed rapid leaf senescence. Thus, the RLS3 gene plays key roles in sustaining the normal growth of rice, while loss of function in RLS3 leads to rapid leaf senescence. The identification of RLS3 will be helpful to elucidate the mechanisms involved in leaf senescence in rice.展开更多
Nitrogen fixation is essential for all forms of life,as nitrogen is required to biosynthesize fundamental building blocks of creatures,plants,and other life forms.As the main method of artificial nitrogen fixation,Ha...Nitrogen fixation is essential for all forms of life,as nitrogen is required to biosynthesize fundamental building blocks of creatures,plants,and other life forms.As the main method of artificial nitrogen fixation,Haber–Bosch process(ammonia synthesis)has been supporting the agriculture and chemical industries since the 1910s.However,the disadvantages inherent to the Haber–Bosch process,such as high energy consumption and high emissions,cannot be ignored.Therefore,developing a green nitrogen fixation process has always been a research hotspot.Among the various technologies,plasma-assisted nitrogen fixation technology is very promising due to its small scale,mild reaction conditions,and flexible parameters.In the present work,the basic principles of plasma nitrogen fixation technology and its associated research progress are reviewed.The production efficiency of various plasmas is summarized and compared.Eventually,the prospect of nitrogen fixation using low-temperature plasma in the future was proposed.展开更多
Due to competitive adsorption between CO_(2) and H_(2)O,hydrogen evolution reaction reacts easily in the photothermal CO_(2) reduction.Herein,the amphoteric oxide loaded on TiO_(2) catalyst was prepared to enhance CO_...Due to competitive adsorption between CO_(2) and H_(2)O,hydrogen evolution reaction reacts easily in the photothermal CO_(2) reduction.Herein,the amphoteric oxide loaded on TiO_(2) catalyst was prepared to enhance CO_(2) adsorption as well as improve the photo-responsive properties.The samples with 10% mass fraction of ZnO loaded on TiO_(2) exhibited the best photothermal catalytic performance.The average yields of H_(2),CO and CH4 were estimated to be 35.7,43.5,and 5.7μmol/(g·h),respectively.Also,the selectivity of carbon-containing products increased from 28.9% to 48.8% when compared to P25.The loading of amphoteric oxides can act as adsorption sites on the material surface to adsorb acidic molecules of CO_(2) for reaction,improving the selectivity of carbon-containing products.In addition,amphoteric oxides are good semiconductors,which can improve the photo-responsive properties of the catalyst and form heterostructures with TiO_(2) to promote the separation of photogenerated electron-hole pairs,allowing more photo-generated carriers to participate in the reaction.Finally,both functions including CO_(2) adsorption and solar light absorption could be realized on the all-in-one amphoteric oxide loaded on TiO_(2) component.展开更多
A novel method to apply artificial neural network (ANN) for both chemical kinetics reduction and source term evaluation is introduced and tested in direct numerical simulation (DNS) and large eddy simulation (LES) of ...A novel method to apply artificial neural network (ANN) for both chemical kinetics reduction and source term evaluation is introduced and tested in direct numerical simulation (DNS) and large eddy simulation (LES) of reactive flows. To gather turbulence affected flame data for ANN training, a new computation-economical method, called 1D pseudo-velocity disturbed flame (PVDF), is developed and used to generate thermo-chemical states independent of the modeled flame. Then a back-propagation ANN is trained using scaled conjugate gradient algorithm to memorize the sample states with reduced orders. The new method is employed in DNS and LES modeling of H2 /air and C3H8 /air premixed flames experiencing various levels of turbulence. The test result shows that compared to traditional computation with full mechanism and direct integration, this method can obtain quite large speed-ups with adequate prediction accuracy.展开更多
Ammonia(NH_(3))synthesis via electrocatalytic nitrogen reduction generally suffers from low NH_(3)yield and faradaic efficiency.Compared with activating stable,low-solubility N_(2),the electrochemical conversion of ni...Ammonia(NH_(3))synthesis via electrocatalytic nitrogen reduction generally suffers from low NH_(3)yield and faradaic efficiency.Compared with activating stable,low-solubility N_(2),the electrochemical conversion of nitrates to ammonia provides a more reasonable route for NH_(3)production.Herein,we introduce Ar-plasma to enhance the interaction between copper-nickel alloys and carbon substrate to improve the performance of NH_(3)production.The NH_(3)faradaic efficiency from nitrate is nearly 100%and the yield rate is over 6000μgNH_(3)cm^(−2)h^(−1).DFT(density functional theory)calculation reveals the high performance of Cu_(50)Ni_(50)originates from the lower energy barrier on the reaction path and the closer position to the Fermi level of the d-band center.This work offers a promising strategy for plasma-modified electrocatalyst to promote ammonia synthesis via nitrate reduction.展开更多
Liquid fuel intermediates could be produced via aldol condensation reaction between furfural or 5-hydroxymethylfurfural(HMF)and acetone.It was found that iron-modified MCM-41 zeolite can be an effective Lewis acid cat...Liquid fuel intermediates could be produced via aldol condensation reaction between furfural or 5-hydroxymethylfurfural(HMF)and acetone.It was found that iron-modified MCM-41 zeolite can be an effective Lewis acid catalyst for C-C bond formation via aldol condensation of furfural or HMF with acetone.The 4-(2-furyl)-3-buten-2-one and 1,5-di-2-furanyl-1,4-pentadien-3-one(FAc and F_(2)Ac),or 1,5-di-2-furanyl-1,4-pentadien-3-one and 1,5-bis[(5-hydroxlmethyl)-2-furanyl]-1,4-pentadien-3-one(HAc and H_(2)Ac),as two main condensation products of furfural with acetone or HMF with acetone,were observed.After 24 h at 160℃,86.9%conversion of furfural with 60.0%yield of the FAc as well as 7.5%yield of the F_(2)Ac and 88.9%conversion of the HMF with 41.1%yield of the HAc as well as 3.5%yield of the H_(2)Ac were achieved.Although furfural or HMF conversion was almost same after 24 h at 160℃,iron-modified MCM-41 zeolite catalyst displayed an enhanced selectivity to condensation products of furfural with acetone.In addition,catalysts showed an improved selectivity to the F_(2)Ac and H_(2)Ac at higher reaction temperature.The reusability and regeneration studies showed that iron-modified MCM-41 zeolite catalyst could not be reused directly,but could be regenerated by calcination in air,and the catalytic perfor-mance of regenerated catalyst was acceptable.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.W2412060,22325902 and 52171215)the State Key Laboratory of Clean Energy Utilization(Open Fund Project No.ZJUCEU2023002)。
文摘Sodium-ion batteries(SIBs)have attracted significant attention in large-scale energy storage system because of their abundant sodium resource and cost-effectiveness.Layered oxide materials are particularly promising as SIBs cathodes due to their high theoretical capacities and facile synthesis.However,their practical applications are hindered by the limitations in energy density and cycling stability.The comprehensive understanding of failure mechanisms within bulk structure and at the cathode/electrolyte interface of cathodes is still lacking.In this review,the issues related to bulk phase degradation and surface degradation,such as irreversible phase transitions,cation migration,transition metal dissolution,air/moisture instability,intergranular cracking,interfacial reactions,and reactive oxygen loss,are discussed.The latest advances and strategies to improve the stability of layered oxide cathodes and full cells are provided,as well as our perspectives on the future development of SIBs.
基金supported in part by the National Key Research and Development Program of China under Grant 2023YFA1011803in part by Natural Science Foundation of Chongqing,China under Grant CSTB2023NSCQ-MSX0588+2 种基金in part by the Fundamental Research Funds for the Central Universities,China under Grant 2023CDJKYJH047in part by the National Natural Science Foundation of China under Grant 62273064,Grant 61991400,Grant 61991403,Grant 61933012,Grant 62250710167,Grant 62203078in part by Innovation Support Program for International Students Returning to China under Grant cx2022016.
文摘This paper addresses the lane-keeping control problem for autonomous ground vehicles subject to input saturation and uncertain system parameters.An enhanced adaptive terminal sliding mode based prescribed performance control scheme is proposed,which enables the lateral position error of the vehicle to be kept within the prescribed performance boundaries all the time.This is achieved by firstly introducing an improved performance function into the controller design such that the stringent initial condition requirements can be relaxed,which further allows the global prescribed performance control result,and then,developing a multivariable adaptive terminal sliding mode based controller such that both input saturation and parameter uncertainties are handled effectively,which further ensures the robust lane-keeping control.Finally,the proposed control strategy is validated through numerical simulations,demonstrating its effectiveness.
基金support from the National Natural Science Foundation of China(22302137,52172221,52272229,51920105005)the Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices(ZZ2201)+1 种基金the Suzhou Key Laboratory of Advanced Photonic Materialsthe Collaborative Innovation Center of Suzhou Nano Science&Technology.
文摘Photothermal catalysis represents an emerging technology for solar energy conversion that combines the principles and advantages of photoand thermal catalytic mechanisms[1–5].Driven by the inter/intra-band transitions and subsequent electron-phonon scattering processes,photothermal catalysts can achieve rapid and highly localized heating,providing thermal activation to the chemical conversions.Besides,direct participation of photo-generated charge carriers could also drastically reduce the activation energy barriers and modulate the catalytic pathways.However,distinction between thermal and non-thermal contributions remains a key challenge for both fundamental understandings and large-scale applications of photothermal catalysis[6,7].This issue is largely due to a lack of precise in-situ surface-temperature measurement techniques that accurately quantify the light-to-heat conversion under reaction conditions at the nanoscale.Conventional macroscopic temperature measurement techniques,such as infrared cameras and thermocouples,suffer from the lack of spatiotemporal resolutions required for the localized photothermal conversion.They are,thus,measuring an average temperature of the ambient medium.Besides,they typically cannot be applied in in-situ temperature measurements,which is crucial since inaccurate heat dissipation rates may be predicted by ex-situ temperature measurement techniques.For instance,differences in gas pressure,composition and flow rate could lead to significantly different convective heat fluxes.
基金Project (No. 51006088) supported by the National Natural Science Foundation of China
文摘This study aimed to establish a closed-cycle operation technology with high thermal efficiency in the thermochemical sulfur-iodine cycle for large-scale hydrogen production.A series of experimental studies were performed to investigate the occurrence of side reactions in both the H2SO4 and HI x phases from the H2SO4/HI/I2/H2O quaternary system within a constant temperature range of 323-363 K.The effects of iodine content,water content and reaction temperature on the side reactions were evaluated.The results showed that an increase in the reaction temperature promoted the side reactions.However,they were prevented as the iodine or water content increased.The occurrence of side reactions was faster in kinetics and more intense in the H2SO4 phase than in the HI x phase.The sulfur or hydrogen sulfide formation reaction or the reverse Bunsen reaction was validated under certain conditions.
文摘Myanmar is located in Southeast Asia within the Mekong River Basin. The estimated annual surface and groundwater potentials are 1 081 km^3 and 494 km^3, respectively. Based on geological conditions, 11 different types of aquifers have been classified in Myanmar. The recent alluvial formation, Irrawaddy formation, Upper Pegu Group and Plateau limestone formation are the major water-bearing geologic formations of the country. In Myanmar, 89% of the groundwater is used for agriculture, approximately 8% is used for domestic consumption, and 3% is used for industrial purposes. Climate change projections for Myanmar from 2001 to 2100 predict general increases in temperature, clear-sky days, rainfall variability and flooding risks and a greater occurrence and intensity of extreme weather events across the country. Additional technology and investments are required to achieve groundwater resource security in response to climate changes. In addition, methods of ensuring the sustainability of groundwater resources must be implemented via collaborations with other countries and international sources.
基金This work is supported by the National Natural Science Foundation of China(No.51976181).
文摘The two-phase flow maldistribution phenomenon in microchannels with multi-parallel branches is inevitable in almost all common conditions,and not only affects the performance of the facility but also increases the risk of system instability.In order to better understand the distribution mechanism and to explore a potential strategy to improve uniformity,the pressure evolutions under different split modes in a microchannel with multi-parallel branches,were analyzed numerically.The results show that the fluctuations of transient pressure exhibit similar trends at various split modes,but the time-averaged pressure drops in the branches are very different.This may be related to the maldistribution of mass flow.Thus,the outlet pressures of the branches are numerically changed to explore the relationship between differential pressure and flow distribution.From this study,the flow distribution is seen to display a strong sensitivity to the branch differential pressure.By changing the pressure conditions,the gas flow of the middle branch can be effectively prevented from the main channel,and the flow type in this branch turns from gas-liquid to a single liquid phase.When the differential pressure of the first branch channel changes,the maldistribution phenomenon of the model can be mitigated to a certain extent.Based on this,by adjusting the differential pressures of the second branch,the maldistribution phenomenon can be further mitigated,and the normalized standard deviation(NSTD)decreases from 0.52 to approximately 0.26.The results and conclusions are useful in understanding the two-phase flow distribution mechanism and for seeking optimizing strategies.
基金financially supported by the National HighTech R&D Program of China (2011AA100104)the National Basic Research Program of China (2013CB127705)+1 种基金the National Natural Science Foundation of China (31030056, 31210103902)the Introducing Talents of Disciplines to Universities,Ministry of Education (MOE) of China (111-02-3)
文摘Powdery mildew, caused by Blumeria graminis f. sp. tritici, is one of the most devastating wheat diseases. Wild emmer wheat（Triticum turgidum ssp. dicoccoides） is a promising source of disease resistance for wheat. A powdery mildew resistance gene conferring resistance to B. graminis f. sp. tritici isolate E09, originating from wild emmer wheat, has been transferred into the hexaploid wheat line WE4 through crossing and backcrossing. Genetic analyses indicated that the powdery mildew resistance was controlled by a single dominant gene, temporarily designated Ml WE4. By mean of comparative genomics and bulked segregant analysis, a genetic linkage map of Ml WE4 was constructed, and Ml WE4 was mapped on the distal region of chromosome arm 5BL. Comparative genetic linkage maps showed that genes Ml WE4, Pm36 and Ml3D232 were co-segregated with markers XBD37670 and XBD37680, indicating they are likely the same gene or alleles in the same locus. The co-segregated markers provide a starting point for chromosome landing and map-based cloning of Ml WE4, Pm36 and Ml3D232.
文摘The Global Geopotential Models (GGMs) of GOCE (Gravity Recovery and steady- state Ocean Circulation Explorer) differ globally as well as regionally in their accuracy and resolution based on the maximum degree and order (d/o) of the fully normalized spherical harmonic (SH) coefficients, which express each GGM. The main idea of this study is to compare the free-air gravity anomalies and quasi geoid heights determined from several recent GOCE-based GGMs with the corresponding ones from the Earth Gravitational Model 2008 (EGM2008) over Egypt on the one hand and with ground-based measurements on the other hand. The results regarding to the comparison of GOCE-based GGMs with terrestrial gravity and GPS/levelling data provide better improvement with respect to EGM2008. The 4th release GOCE-based GGM developed with the use of space-wise solution strategy (SPW_R4) approximates the gravity field well over the Egyptian region. The SPW_R4 model is accordingly suggested as a reference model for recovering the long wavelength (up to SH d/o 200) components of quasi geoid heights when modelling the gravimetric quasi-geoid over the Egypt. Finally, three types of transformation models: Four-, Five- and Seven-parameter transformations have been applied to reduce the data biases and to provide a better fitting of quasi geoid heights obtained from the studied GOCE-based GGMs to those from GPS/levelling data. These models reveal that the standard deviation of vertical datum over Egypt is at the level of about 32 cm.
文摘The gravity field and steady-state ocean circulation explorer (GOCE) satellite mission has provided numerous Global Geopotential Models (GGMs) with different processing methodologies and model accuracies. In the current contribution, the latest releases of GOCE-based GGMs are evaluated on the regional scale using the available terrestrial GPS/Levelling and gravity data collected over Egypt. To overcome the spectral inconsistency between the GOCE-based GGMs and the ground-based data, the spectral enhancement method (SEM) is applied. Five of GOCE-based GGMs have been used, namely GOSG01S, IGGT_R1, IfE_GOCE05s_ GO_CONS_GCF_2_SPW_R5 (SPW_R5 in the following) and NULP-02. The evaluation process of GOCE-based GGMs with the available ground data over Egypt considering the SEM method shows remarkable improvements obtained from the SPW_R5 model. The model provides lower differences of the standard deviations with respect to the EGM2008 and the other applied geopotential gravity models as well as the applied ground-based gravity and GPS/Levelling data. The findings regarding the ground-based data show obvious reductions of about 15.16% and 32.22% achieved by the GOCE-based model in term of standard deviations differences of gravity anomalies and geoid heights, respectively. Therefore, the SPW_R5 model is recommended to be applied as a reference model for compensating the long-to-short wavelength (up to spherical harmonics degree/order 280) components when modelling the gravimetric geoid over Egypt.
文摘This paper presents a closed-loop vector control structure based on adaptive Fuzzy Logic Sliding Mode Controller (FL-SMC) for a grid-connected Wave Energy Conversion System (WECS) driven Self-Excited Induction Generator (SEIG). The aim of the developed control method is to automatically tune and optimize the scaling factors and the membership functions of the Fuzzy Logic Controllers (FLC) using Multi-Objective Genetic Algorithms (MOGA) and Multi-Objective Particle Swarm Optimization (MOPSO). Two Pulse Width Modulated voltage source PWM converters with a carrier-based Sinusoidal PWM modulation for both Generator- and Grid-side converters have been connected back to back between the generator terminals and utility grid via common DC link. The indirect vector control scheme is implemented to maintain balance between generated power and power supplied to the grid and maintain the terminal voltage of the generator and the DC bus voltage constant for variable rotor speed and load. Simulation study has been carried out using the MATLAB/Simulink environment to verify the robustness of the power electronics converters and the effectiveness of proposed control method under steady state and transient conditions and also machine parameters mismatches. The proposed control scheme has improved the voltage regulation and the transient performance of the wave energy scheme over a wide range of operating conditions.
基金support of the National Key Research and Development Program of China(2022YFE0206600)the National Natural Science Foundation of China(52376125)Fundamental Research Funds for the Central Universities.
文摘Oxy-combustion is a promising carbon-capture technology,but atmospheric-pressure oxy-combustion has a relatively low net efficiency,limiting its application in power plants.In pressurized oxycombustion(POC),the boiler,air separation unit,flue gas recirculation unit,and CO_(2)purification and compression unit are all operated at elevated pressure;this makes the process more efficient,with many advantages over atmospheric pressure,such as low NO_(x)emissions,a smaller boiler size,and more.POC is also more promising for industrial application and has attracted widespread research interest in recent years.It can produce high-pressure CO_(2)with a purity of approximately 95%,which can be used directly for enhanced oil recovery or geo-sequestration.However,the pollutant emissions must meet the standards for carbon capture,storage,and utilization.Because of the high oxygen and moisture concentrations in POC,the formation of acids via the oxidation and solution of SO_(x)and NO_(x)can be increased,causing the corrosion of pipelines and equipment.Furthermore,particulate matter(PM)and mercury emissions can harm the environment and human health.The main distinction between pressurized and atmospheric-pressure oxy-combustion is the former’s elevated pressure;thus,the effect of this pressure on the pollutants emitted from POC—including SO_(x),NO_(x),PM,and mercury—must be understood,and effective control methodologies must be incorporated to control the formation of these pollutants.This paper reviews recent advances in research on SO_(x),NO_(x),PM,and mercury formation and control in POC systems that can aid in pollutant control in such systems.
基金supported by grants from the National Key Research and Development Program(2018YFD1000200)the National Natural Science Foundation of China(32072539 and 31772275).
文摘Abstract Cuticular wax covers the surface of the apple epidermis and plays an important role in water loss and pathogen resistance.However,little is known about wax biosynthesis during apple fruit development.In this study,the morphological structure and chemical composition of wax and the transcription patterns of wax-related genes were investigated in the'Red Delicious'and'Golden Delicious'cultivars.The results showed that accumulation of the waxy layer was synchronized with enlargement and maturation of fruit.The crystal structure,major chemical components(very long chain fatty acids and triterpenes)of wax and the expression levels of wax-related genes varied significantly 90 days after flowering(DAF),indicating that the critical period for biosynthesis of cuticular wax was about 90 DAF.This finding is valuable for further study of the regulatory mechanism of wax biosynthesis at both the molecular and physiological levels.
文摘Leaf senescence plays an important role in crop developmental processes that dramatically affect crop yield and grain quality. The genetic regulation of leaf senescence is complex, involving many metabolic and signaling pathways. Here, we identified a rapid leaf senescence 3 （rls3） mutant that displayed accelerated leaf senescence, shorter plant height and panicle length, and lower seed set rate than the wild type. Map-based cloning revealed that RLS3 encodes a protein with AAA＋ domain, localizing it to chloroplasts. Sequence analysis found that the rls3 8ene had a single-nucleotide substitution （G--~A） at the splice site of the Ioth intron/11th exon, resulting in the cleavage of the first nucleotide in 11th exon and premature termination of P, LS3 protein translation. Using transmission electron microscope, the chloroplasts of the rls3 mutant were observed to degrade much faster than those of the wild type. The investigation of the leaf senescence process under dark incubation conditions further revealed that the rls3 mutant displayed rapid leaf senescence. Thus, the RLS3 gene plays key roles in sustaining the normal growth of rice, while loss of function in RLS3 leads to rapid leaf senescence. The identification of RLS3 will be helpful to elucidate the mechanisms involved in leaf senescence in rice.
基金The funding has been recevied from National Natural Science Foundation of China with Grant No.51806193National Natural Science Foundation of China with Grant No.51976191.
文摘Nitrogen fixation is essential for all forms of life,as nitrogen is required to biosynthesize fundamental building blocks of creatures,plants,and other life forms.As the main method of artificial nitrogen fixation,Haber–Bosch process(ammonia synthesis)has been supporting the agriculture and chemical industries since the 1910s.However,the disadvantages inherent to the Haber–Bosch process,such as high energy consumption and high emissions,cannot be ignored.Therefore,developing a green nitrogen fixation process has always been a research hotspot.Among the various technologies,plasma-assisted nitrogen fixation technology is very promising due to its small scale,mild reaction conditions,and flexible parameters.In the present work,the basic principles of plasma nitrogen fixation technology and its associated research progress are reviewed.The production efficiency of various plasmas is summarized and compared.Eventually,the prospect of nitrogen fixation using low-temperature plasma in the future was proposed.
基金financially supported by National Natural Science Foundation of China(No.51976190)the Zhejiang Provincial Natural Science Foundation(No.LR18E060001).
文摘Due to competitive adsorption between CO_(2) and H_(2)O,hydrogen evolution reaction reacts easily in the photothermal CO_(2) reduction.Herein,the amphoteric oxide loaded on TiO_(2) catalyst was prepared to enhance CO_(2) adsorption as well as improve the photo-responsive properties.The samples with 10% mass fraction of ZnO loaded on TiO_(2) exhibited the best photothermal catalytic performance.The average yields of H_(2),CO and CH4 were estimated to be 35.7,43.5,and 5.7μmol/(g·h),respectively.Also,the selectivity of carbon-containing products increased from 28.9% to 48.8% when compared to P25.The loading of amphoteric oxides can act as adsorption sites on the material surface to adsorb acidic molecules of CO_(2) for reaction,improving the selectivity of carbon-containing products.In addition,amphoteric oxides are good semiconductors,which can improve the photo-responsive properties of the catalyst and form heterostructures with TiO_(2) to promote the separation of photogenerated electron-hole pairs,allowing more photo-generated carriers to participate in the reaction.Finally,both functions including CO_(2) adsorption and solar light absorption could be realized on the all-in-one amphoteric oxide loaded on TiO_(2) component.
基金supported by the National Natural Science Foundation of China (51176169)the Program of Introducing Talents of Discipline to University (B08026)
文摘A novel method to apply artificial neural network (ANN) for both chemical kinetics reduction and source term evaluation is introduced and tested in direct numerical simulation (DNS) and large eddy simulation (LES) of reactive flows. To gather turbulence affected flame data for ANN training, a new computation-economical method, called 1D pseudo-velocity disturbed flame (PVDF), is developed and used to generate thermo-chemical states independent of the modeled flame. Then a back-propagation ANN is trained using scaled conjugate gradient algorithm to memorize the sample states with reduced orders. The new method is employed in DNS and LES modeling of H2 /air and C3H8 /air premixed flames experiencing various levels of turbulence. The test result shows that compared to traditional computation with full mechanism and direct integration, this method can obtain quite large speed-ups with adequate prediction accuracy.
基金supported by the National Natural Science Foundation of China(No.51976191)the State Key Laboratory of Clean Energy Utilization(No.ZJUCEU2021003),Ecological civilization project,Zhejiang University and the Fundamental Research Funds for the Central Universities.
文摘Ammonia(NH_(3))synthesis via electrocatalytic nitrogen reduction generally suffers from low NH_(3)yield and faradaic efficiency.Compared with activating stable,low-solubility N_(2),the electrochemical conversion of nitrates to ammonia provides a more reasonable route for NH_(3)production.Herein,we introduce Ar-plasma to enhance the interaction between copper-nickel alloys and carbon substrate to improve the performance of NH_(3)production.The NH_(3)faradaic efficiency from nitrate is nearly 100%and the yield rate is over 6000μgNH_(3)cm^(−2)h^(−1).DFT(density functional theory)calculation reveals the high performance of Cu_(50)Ni_(50)originates from the lower energy barrier on the reaction path and the closer position to the Fermi level of the d-band center.This work offers a promising strategy for plasma-modified electrocatalyst to promote ammonia synthesis via nitrate reduction.
基金supported by National Key R&D Program of China(No.2018YFB1501601)National Natural Science Foundation of China(No.51676178)Transformational Technologies for Clean Energy and Demonstration,and Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA 21060101).
文摘Liquid fuel intermediates could be produced via aldol condensation reaction between furfural or 5-hydroxymethylfurfural(HMF)and acetone.It was found that iron-modified MCM-41 zeolite can be an effective Lewis acid catalyst for C-C bond formation via aldol condensation of furfural or HMF with acetone.The 4-(2-furyl)-3-buten-2-one and 1,5-di-2-furanyl-1,4-pentadien-3-one(FAc and F_(2)Ac),or 1,5-di-2-furanyl-1,4-pentadien-3-one and 1,5-bis[(5-hydroxlmethyl)-2-furanyl]-1,4-pentadien-3-one(HAc and H_(2)Ac),as two main condensation products of furfural with acetone or HMF with acetone,were observed.After 24 h at 160℃,86.9%conversion of furfural with 60.0%yield of the FAc as well as 7.5%yield of the F_(2)Ac and 88.9%conversion of the HMF with 41.1%yield of the HAc as well as 3.5%yield of the H_(2)Ac were achieved.Although furfural or HMF conversion was almost same after 24 h at 160℃,iron-modified MCM-41 zeolite catalyst displayed an enhanced selectivity to condensation products of furfural with acetone.In addition,catalysts showed an improved selectivity to the F_(2)Ac and H_(2)Ac at higher reaction temperature.The reusability and regeneration studies showed that iron-modified MCM-41 zeolite catalyst could not be reused directly,but could be regenerated by calcination in air,and the catalytic perfor-mance of regenerated catalyst was acceptable.
