New chemistries are being developed to increase the capacity and power of rechargeable batteries. However, the risk of safety issues increases when high-energy batteries using highly active materials encounter harsh o...New chemistries are being developed to increase the capacity and power of rechargeable batteries. However, the risk of safety issues increases when high-energy batteries using highly active materials encounter harsh operating conditions. Here we report on the synthesis of a unique ionogel electrolyte for abuse-tolerant lithium batteries. A hierarchically architected silica/polymer scaffold is designed and fabricated through a facile soft chemistry route, which is competent to confine ionic liquids with superior uptake ability (92.4 wt%). The monolithic ionogel exhibits high conductivity and thermal/mechanical stability, featuring high-temperature elastic modulus and dendrite-free lithium cycling. The Li/LiFePO_(4) pouch cells achieve outstanding cyclability at different temperatures up to 150 ℃, and can sustain cutting, crumpling, and even coupled thermal–mechanical abuses. Moreover, the solid-state lithium batteries with LiNi_(0.60)Co_(0.20)Mn_(0.20)O_(2), LiNi_(0.80)Co_(0.15)Al_(0.05)O_(2), and Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2) cathodes demonstrate excellent cycle performances at 60 ℃. These results indicate that the resilient and high-conductivity ionogel electrolyte is promising to realize high-performance lithium batteries with high energy density and safety.展开更多
In this work,n-pentane catalytic cracking over HZSM-5 zeolites was studied at 650°C under atmosphere pressure.A particular attention was paid to the measurement of n-pentane conversion,light olefins production,pr...In this work,n-pentane catalytic cracking over HZSM-5 zeolites was studied at 650°C under atmosphere pressure.A particular attention was paid to the measurement of n-pentane conversion,light olefins production,product distribution,coke deposit,etc.Several indexes were defined to evaluate the effects of operating conditions on the catalytic performance of HZSM-5 zeolites.It was found that decreasing the weight hourly space velocity,increasing the reactant partial pressure,and increasing the carrier gas flow rate could inhibit C-H bond breaking and enhance the C-C bond breaking and hydride transfer reactions,leading to reduced alkenes selectivity,which suppressed the formation of external coke and alleviated the deactivation of HZSM-5 zeolites.It was deduced that the catalytic stability of HZSM-5 zeolites was improved at the cost of alkenes selectivity.Compared with decreasing the weight hourly space velocity and increasing the reactant partial pressure,increasing the carrier gas flow rate could enhance the diffusion process and protect alkenes from being consumed in coke formation in order to improve the catalytic stability of HZSM-5 zeolites with less reduction of alkenes selectivity.展开更多
The effects of operating conditions on the distribution of olefins in the FCC gasoline, obtained during catalytic cracking reaction in the presence of the GOR-Q catalyst and conventional MLC-500 catalyst, have been st...The effects of operating conditions on the distribution of olefins in the FCC gasoline, obtained during catalytic cracking reaction in the presence of the GOR-Q catalyst and conventional MLC-500 catalyst, have been studied in detail. The test results showed that the GOR-Q catalyst could obviously reduce the content of several kinds of olefins in FCC gasoline. Olefins in the FCC gasoline consist mainly of C5- C7 compounds, that are composed of C=C bond with normal or mono- branched chains. The reduction of gasoline olefin content could be achieved by decreasing the content of above-mentioned olefins. Lower reaction temperature, lower weight hourly space velocity （WHSV） and higher catalyst to oil ratio would help to reduce the content of olefins with a C = C double bond, normal olefins, mono-branched-chain olefins and diolefins. To decrease the loss of gasoline octane number, the operation for olefin reduction should be firstly focused on increasing the catalyst to oil ratio.展开更多
Blades are important parts of rotating machinery such as marine gas turbines and wind turbines,which are exposed to harsh environments during mechanical operations,including centrifugal loads,aerodynamic forces,or hig...Blades are important parts of rotating machinery such as marine gas turbines and wind turbines,which are exposed to harsh environments during mechanical operations,including centrifugal loads,aerodynamic forces,or high temperatures.These demanding working conditions considerably influence the dynamic performance of blades.Therefore,because of the challenges posed by blades in complex working environments,in-depth research and optimization are necessary to ensure that blades can operate safely and efficiently,thus guaranteeing the reliability and performance of mechanical systems.Focusing on the vibration analysis of blades in rotating machinery,this paper conducts a comprehensive literature review on the research advancements in vibration modeling and structural optimization of blades under complex operational conditions.First,the paper outlines the development of several modeling theories for rotating blades,including one-dimensional beam theory,two-dimensional plate-shell theory,and three-dimensional solid theory.Second,the research progress in the vibrational analysis of blades under aerodynamic loads,thermal environments,and crack factors is separately discussed.Finally,the developments in rotating blade structural optimization are presented from material optimization and shape optimization perspectives.The methodology and theory of analyzing and optimizing blade vibration characteristics under multifactorial operating conditions are comprehensively outlined,aiming to assist future researchers in proposing more effective and practical approaches for the vibration analysis and optimization of blades.展开更多
Iron nickel oxide catalysts were prepared using co-precipitation procedure and studied for the conversion of synthesis gas to light olefins.In particular,the effects of a range of preparation variables such as Fe/Ni m...Iron nickel oxide catalysts were prepared using co-precipitation procedure and studied for the conversion of synthesis gas to light olefins.In particular,the effects of a range of preparation variables such as Fe/Ni molar ratios of the precipitation solution,precipitate aging times,calcination conditions,different supports and loading of optimum support on the structure of catalysts and their catalytic performance for the tested reaction were investigated.It was found that the catalyst containing 40%Fe/60%Ni/40wt%Al 2O3 ,which was aged for 180 min and calcined at 600 ℃ for 6 h was the optimum modified catalyst.The catalytic performance of optimal catalyst has been studied in different operation conditions such as reaction temperatures,H2 /CO molar feed ratios and reaction total pressure.Characterization of both precursors and calcined catalysts was carried out by powder X-ray diffraction（XRD）,scanning electron microscopy（SEM）,Brunauer-Emmett-Teller（BET） surface area measurements,thermal analysis methods such as thermal gravimetric analysis（TGA） and differential scanning calorimetry（DSC）.展开更多
Hydrogen production by proton exchange membrane electrolysis has good fluctuation adaptability,making it suitable for hydrogen production by electrolysis in fluctuating power sources such as wind power.However,current...Hydrogen production by proton exchange membrane electrolysis has good fluctuation adaptability,making it suitable for hydrogen production by electrolysis in fluctuating power sources such as wind power.However,current research on the durability of proton exchange membrane electrolyzers is insufficient.Studying the typical operating conditions of wind power electrolysis for hydrogen production can provide boundary conditions for performance and degradation tests of electrolysis stacks.In this study,the operating condition spectrum of an electrolysis stack degradation test cycle was proposed.Based on the rate of change of the wind farm output power and the time-averaged peak-valley difference,a fluctuation output power sample set was formed.The characteristic quantities that played an important role in the degradation of the electrolysis stack were selected.Dimensionality reduction of the operating data was performed using principal component analysis.Clustering analysis of the data segments was completed using an improved Gaussian mixture clustering algorithm.Taking the annual output power data of wind farms in Northwest China with a sampling rate of 1 min as an example,the cyclic operating condition spectrum of the proton-exchange membrane electrolysis stack degradation test was constructed.After preliminary simulation analysis,the typical operating condition proposed in this paper effectively reflects the impact of the original curve on the performance degradation of the electrolysis stack.This study provides a method for evaluating the degradation characteristics and system efficiency of an electrolysis stack due to fluctuations in renewable energy.展开更多
A series of x （Fe,Ni）/Al2O3 catalysts （x = 2-12 wt%） were prepared using incipient wetness method and studied for the conversion of synthesis gas to light olefins.6 wt%（Fe,Ni）/Al2O3 catalyst was found to be the ...A series of x （Fe,Ni）/Al2O3 catalysts （x = 2-12 wt%） were prepared using incipient wetness method and studied for the conversion of synthesis gas to light olefins.6 wt%（Fe,Ni）/Al2O3 catalyst was found to be the optimal catalyst for the production of C2-C4 olefins.The effects of calcination behaviors and operational conditions on the catalytic performance of the optimal catalyst were investigated.The best operational conditions were molar feed ratio H2/CO = 2/1,T = 260 ℃,gas hourly space velocity （GHSV） = 2600 h^-1 and the pressure of 3 bar.Character-izations of both precursors and catalysts were carried out using X-ray diffraction （XRD）,temperature-programmed reduction （TPR）,scanning electron microscopy （SEM）,N2-adsorption-desorption measurement,thermal gravimetric analysis （TGA） and differential scanning calorimetry （DSC）.展开更多
Cobalt-manganese nano catalysts were prepared by sol-gel method. This research investigated the effects of different cobalt-manganese （Co/Mn = 1/1） loading, pH and calcination conditions on the catalytic performance...Cobalt-manganese nano catalysts were prepared by sol-gel method. This research investigated the effects of different cobalt-manganese （Co/Mn = 1/1） loading, pH and calcination conditions on the catalytic performance of Co-Mn/TiO2 catalysts for Fischer-Tropsch synthesis （FTS） in a fixed bed reactor. It was found that the catalyst containing 30wt%（Co-Mn）/TiO2 was an optimal catalyst for the conversion of synthesis gas to light olefins especially propylene. The activity and selectivity of optimal catalyst were studied under different operational conditions. The results showed that the best operational conditions were H2/CO = 1/1 molar feed ratio at 250 ℃ and GHSV = 1300 h-1 un- der atmospheric pressure. Characterization of catalysts was carried out by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, N2 adsorption-desorlation measurements.展开更多
The new numerical approach for analysis of the warhead transportations is suggested.This approach allows to control the warhead operability before its experimental analysis.The approach is implemented by the adequate ...The new numerical approach for analysis of the warhead transportations is suggested.This approach allows to control the warhead operability before its experimental analysis.The approach is implemented by the adequate models for the software ANSYS.Analysis of the loads at land operations and transportations of the warhead by natural roads,water and aviation allows to obtain the maximal values of loads,which are used in numerical simulations of the warhead.These loads give an opportunity to analyze the operability and the fatigue strength of the cartridge warhead.The numerical simulations of the attachments of the warhead combat elements are performed on the basis of the suggested method.The data of the numerical simulations verifies the operability of the fastener system of the warhead combat elements.展开更多
Nanosized Fe-Co catalysts were prepared by co-precipitation method and studied for the conversion of synthesis gas to light olefins.In particular,the effects of a range of preparation variables such as Co/Fe molar rat...Nanosized Fe-Co catalysts were prepared by co-precipitation method and studied for the conversion of synthesis gas to light olefins.In particular,the effects of a range of preparation variables such as Co/Fe molar ratios of the precipitation solution,pH value of precipitate,temperature of precipitation,promoters and loading of optimum promoter on the structure and catalytic performance are investigated.The optimal nano catalyst for light olefins （C2-C4） production was obtained over the catalyst with Co/Fe molar ratio of 3/1 which promoted with 2 wt% K.The results show that the best operational conditions were GHSV=2200 h^-1 （H2/CO=2/1） at 260℃ under atmospheric pressure.Characterization of catalysts were carried out using X-ray diffraction （XRD）,thermal gravimetric analysis （TGA）,differential scanning calorimetry （DSC）,scanning electron microscopy （SEM）,transmission electron microscopy （TEM） and N2 physisorption measurements such as Brunauer-Emmett-Teller （BET） and Barrett-Joyner-Halenda （BJH） methods.展开更多
基金This work is supported by the National Natural Science Foundation of China(No.51972132.51772116 and 52002141)the Program for HUST Academic Frontier Youth Team(2016QYTD04).The authors thank the Analytical and Testing Center of HUST for DMA,TGA measurements,etc.
文摘New chemistries are being developed to increase the capacity and power of rechargeable batteries. However, the risk of safety issues increases when high-energy batteries using highly active materials encounter harsh operating conditions. Here we report on the synthesis of a unique ionogel electrolyte for abuse-tolerant lithium batteries. A hierarchically architected silica/polymer scaffold is designed and fabricated through a facile soft chemistry route, which is competent to confine ionic liquids with superior uptake ability (92.4 wt%). The monolithic ionogel exhibits high conductivity and thermal/mechanical stability, featuring high-temperature elastic modulus and dendrite-free lithium cycling. The Li/LiFePO_(4) pouch cells achieve outstanding cyclability at different temperatures up to 150 ℃, and can sustain cutting, crumpling, and even coupled thermal–mechanical abuses. Moreover, the solid-state lithium batteries with LiNi_(0.60)Co_(0.20)Mn_(0.20)O_(2), LiNi_(0.80)Co_(0.15)Al_(0.05)O_(2), and Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2) cathodes demonstrate excellent cycle performances at 60 ℃. These results indicate that the resilient and high-conductivity ionogel electrolyte is promising to realize high-performance lithium batteries with high energy density and safety.
基金The authors gratefully acknowledge the financial support from the National Natural Science Foundation of China(Grant No.21908010)the Education Department of Jilin Province(Grant No.JJKH20191314KJ)the Changchun University of Technology.
文摘In this work,n-pentane catalytic cracking over HZSM-5 zeolites was studied at 650°C under atmosphere pressure.A particular attention was paid to the measurement of n-pentane conversion,light olefins production,product distribution,coke deposit,etc.Several indexes were defined to evaluate the effects of operating conditions on the catalytic performance of HZSM-5 zeolites.It was found that decreasing the weight hourly space velocity,increasing the reactant partial pressure,and increasing the carrier gas flow rate could inhibit C-H bond breaking and enhance the C-C bond breaking and hydride transfer reactions,leading to reduced alkenes selectivity,which suppressed the formation of external coke and alleviated the deactivation of HZSM-5 zeolites.It was deduced that the catalytic stability of HZSM-5 zeolites was improved at the cost of alkenes selectivity.Compared with decreasing the weight hourly space velocity and increasing the reactant partial pressure,increasing the carrier gas flow rate could enhance the diffusion process and protect alkenes from being consumed in coke formation in order to improve the catalytic stability of HZSM-5 zeolites with less reduction of alkenes selectivity.
文摘The effects of operating conditions on the distribution of olefins in the FCC gasoline, obtained during catalytic cracking reaction in the presence of the GOR-Q catalyst and conventional MLC-500 catalyst, have been studied in detail. The test results showed that the GOR-Q catalyst could obviously reduce the content of several kinds of olefins in FCC gasoline. Olefins in the FCC gasoline consist mainly of C5- C7 compounds, that are composed of C=C bond with normal or mono- branched chains. The reduction of gasoline olefin content could be achieved by decreasing the content of above-mentioned olefins. Lower reaction temperature, lower weight hourly space velocity （WHSV） and higher catalyst to oil ratio would help to reduce the content of olefins with a C = C double bond, normal olefins, mono-branched-chain olefins and diolefins. To decrease the loss of gasoline octane number, the operation for olefin reduction should be firstly focused on increasing the catalyst to oil ratio.
基金Supported by the National Natural Science Foundation of China under Grant No.52271309Natural Science Foundation of Heilongjiang Province of China under Grant No.YQ2022E104.
文摘Blades are important parts of rotating machinery such as marine gas turbines and wind turbines,which are exposed to harsh environments during mechanical operations,including centrifugal loads,aerodynamic forces,or high temperatures.These demanding working conditions considerably influence the dynamic performance of blades.Therefore,because of the challenges posed by blades in complex working environments,in-depth research and optimization are necessary to ensure that blades can operate safely and efficiently,thus guaranteeing the reliability and performance of mechanical systems.Focusing on the vibration analysis of blades in rotating machinery,this paper conducts a comprehensive literature review on the research advancements in vibration modeling and structural optimization of blades under complex operational conditions.First,the paper outlines the development of several modeling theories for rotating blades,including one-dimensional beam theory,two-dimensional plate-shell theory,and three-dimensional solid theory.Second,the research progress in the vibrational analysis of blades under aerodynamic loads,thermal environments,and crack factors is separately discussed.Finally,the developments in rotating blade structural optimization are presented from material optimization and shape optimization perspectives.The methodology and theory of analyzing and optimizing blade vibration characteristics under multifactorial operating conditions are comprehensively outlined,aiming to assist future researchers in proposing more effective and practical approaches for the vibration analysis and optimization of blades.
文摘Iron nickel oxide catalysts were prepared using co-precipitation procedure and studied for the conversion of synthesis gas to light olefins.In particular,the effects of a range of preparation variables such as Fe/Ni molar ratios of the precipitation solution,precipitate aging times,calcination conditions,different supports and loading of optimum support on the structure of catalysts and their catalytic performance for the tested reaction were investigated.It was found that the catalyst containing 40%Fe/60%Ni/40wt%Al 2O3 ,which was aged for 180 min and calcined at 600 ℃ for 6 h was the optimum modified catalyst.The catalytic performance of optimal catalyst has been studied in different operation conditions such as reaction temperatures,H2 /CO molar feed ratios and reaction total pressure.Characterization of both precursors and calcined catalysts was carried out by powder X-ray diffraction（XRD）,scanning electron microscopy（SEM）,Brunauer-Emmett-Teller（BET） surface area measurements,thermal analysis methods such as thermal gravimetric analysis（TGA） and differential scanning calorimetry（DSC）.
基金supported by the National Key Research and Development Program of China(Materials and Process Basis of Electrolytic Hydrogen Production from Fluctuating Power Sources such as Photovoltaic/Wind Power,No.2021YFB4000100).
文摘Hydrogen production by proton exchange membrane electrolysis has good fluctuation adaptability,making it suitable for hydrogen production by electrolysis in fluctuating power sources such as wind power.However,current research on the durability of proton exchange membrane electrolyzers is insufficient.Studying the typical operating conditions of wind power electrolysis for hydrogen production can provide boundary conditions for performance and degradation tests of electrolysis stacks.In this study,the operating condition spectrum of an electrolysis stack degradation test cycle was proposed.Based on the rate of change of the wind farm output power and the time-averaged peak-valley difference,a fluctuation output power sample set was formed.The characteristic quantities that played an important role in the degradation of the electrolysis stack were selected.Dimensionality reduction of the operating data was performed using principal component analysis.Clustering analysis of the data segments was completed using an improved Gaussian mixture clustering algorithm.Taking the annual output power data of wind farms in Northwest China with a sampling rate of 1 min as an example,the cyclic operating condition spectrum of the proton-exchange membrane electrolysis stack degradation test was constructed.After preliminary simulation analysis,the typical operating condition proposed in this paper effectively reflects the impact of the original curve on the performance degradation of the electrolysis stack.This study provides a method for evaluating the degradation characteristics and system efficiency of an electrolysis stack due to fluctuations in renewable energy.
文摘A series of x （Fe,Ni）/Al2O3 catalysts （x = 2-12 wt%） were prepared using incipient wetness method and studied for the conversion of synthesis gas to light olefins.6 wt%（Fe,Ni）/Al2O3 catalyst was found to be the optimal catalyst for the production of C2-C4 olefins.The effects of calcination behaviors and operational conditions on the catalytic performance of the optimal catalyst were investigated.The best operational conditions were molar feed ratio H2/CO = 2/1,T = 260 ℃,gas hourly space velocity （GHSV） = 2600 h^-1 and the pressure of 3 bar.Character-izations of both precursors and catalysts were carried out using X-ray diffraction （XRD）,temperature-programmed reduction （TPR）,scanning electron microscopy （SEM）,N2-adsorption-desorption measurement,thermal gravimetric analysis （TGA） and differential scanning calorimetry （DSC）.
基金supported by the International Center for Science, High Technology & Environmental Sciences
文摘Cobalt-manganese nano catalysts were prepared by sol-gel method. This research investigated the effects of different cobalt-manganese （Co/Mn = 1/1） loading, pH and calcination conditions on the catalytic performance of Co-Mn/TiO2 catalysts for Fischer-Tropsch synthesis （FTS） in a fixed bed reactor. It was found that the catalyst containing 30wt%（Co-Mn）/TiO2 was an optimal catalyst for the conversion of synthesis gas to light olefins especially propylene. The activity and selectivity of optimal catalyst were studied under different operational conditions. The results showed that the best operational conditions were H2/CO = 1/1 molar feed ratio at 250 ℃ and GHSV = 1300 h-1 un- der atmospheric pressure. Characterization of catalysts was carried out by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, N2 adsorption-desorlation measurements.
文摘The new numerical approach for analysis of the warhead transportations is suggested.This approach allows to control the warhead operability before its experimental analysis.The approach is implemented by the adequate models for the software ANSYS.Analysis of the loads at land operations and transportations of the warhead by natural roads,water and aviation allows to obtain the maximal values of loads,which are used in numerical simulations of the warhead.These loads give an opportunity to analyze the operability and the fatigue strength of the cartridge warhead.The numerical simulations of the attachments of the warhead combat elements are performed on the basis of the suggested method.The data of the numerical simulations verifies the operability of the fastener system of the warhead combat elements.
基金supported by the International Center for Science,High Technology & Environmental Sciences
文摘Nanosized Fe-Co catalysts were prepared by co-precipitation method and studied for the conversion of synthesis gas to light olefins.In particular,the effects of a range of preparation variables such as Co/Fe molar ratios of the precipitation solution,pH value of precipitate,temperature of precipitation,promoters and loading of optimum promoter on the structure and catalytic performance are investigated.The optimal nano catalyst for light olefins （C2-C4） production was obtained over the catalyst with Co/Fe molar ratio of 3/1 which promoted with 2 wt% K.The results show that the best operational conditions were GHSV=2200 h^-1 （H2/CO=2/1） at 260℃ under atmospheric pressure.Characterization of catalysts were carried out using X-ray diffraction （XRD）,thermal gravimetric analysis （TGA）,differential scanning calorimetry （DSC）,scanning electron microscopy （SEM）,transmission electron microscopy （TEM） and N2 physisorption measurements such as Brunauer-Emmett-Teller （BET） and Barrett-Joyner-Halenda （BJH） methods.
