Friction stir welding of dissimilar Al/Mg thick plates still faces severe challenges, such as poor formability, formation of thick intermetallic compounds, and low joint strength. In this work, two joint configuration...Friction stir welding of dissimilar Al/Mg thick plates still faces severe challenges, such as poor formability, formation of thick intermetallic compounds, and low joint strength. In this work, two joint configurations, namely inclined butt(conventional butt) and serrated interlocking(innovative butt), are proposed for improving weld formation and joint quality. The results show that a continuous and straight intermetallic compound layer appears at the Mg side interface in conventional butt joint, and the maximum average thickness reaches about 60.1 μm.Additionally, the Mg side interface also partially melts, forming a eutectic structure composed of Mg solid solution and Al_(12)Mg_(17) phase.For the innovative butt joint, the Mg side interface presents the curved interlocking feature, and intermetallic compounds can be reduced to less than 10 μm. The joint strength of innovative butt joint is more than three times that of conventional butt joint. This is due to the interlocking effect and thin intermetallic compounds in the innovative joint.展开更多
Tin-based materials are very attractive anodes because of their high theoretical capacity,but their rapid capacity fading from volume expansions limits their practical applications during alloying and dealloying proce...Tin-based materials are very attractive anodes because of their high theoretical capacity,but their rapid capacity fading from volume expansions limits their practical applications during alloying and dealloying processes.Herein,the improved binder-free tin-copper intermetallic/carbon nanotubes(Cu6Sn5/CNTs)alloy thin-film electrodes are directly fabricated through efficient in situ electrodeposition from the leaching solution of treated waste-printed circuit boards(WPCBs).The characterization results show that the easily agglomerated Cu6Sn5 alloy nanoparticles are uniformly dispersed across the three-dimensional network when the CNTs concentration in the electrodeposition solution is maintained at 0.2 g·L−1.Moreover,the optimal Cu6Sn5/CNTs-0.2 alloy thin-film electrode can not only provide a decent discharge specific capacity of 458.35 mAh·g^(−1)after 50 cycles at 100 mA·g^(−1)within capacity retention of 82.58%but also deliver a relatively high reversible specific capacity of 518.24,445.52,418.18,345.33,and 278.05 mAh·g^(−1)at step-increased current density of 0.1,0.2,0.5,1.0,and 2.0 A·g^(−1),respectively.Therefore,the preparation process of the Cu6Sn5/CNTs-0.2 alloy thin-film electrode with improved electrochemical performance may provide a cost-effective strategy for the resource utilization of WPCBs to fabricate anode materials for lithium-ion batteries.展开更多
The parameter dependence of transition between electrostatic instabilities is studied using gyrokinetic simulation based on a real discharge of steady-state scenario in the Experimental Advanced Superconducting Tokama...The parameter dependence of transition between electrostatic instabilities is studied using gyrokinetic simulation based on a real discharge of steady-state scenario in the Experimental Advanced Superconducting Tokamak.The scan of radial locations shows that trapped electron mode(TEM)dominates around the core while the ion temperature gradient mode(ITG)simultaneously dominates outside.The maximum growth rate of TEM appears aroundρ=0.24,where the maximum electron temperature gradient R/LTelocates,ρis the normalized poloidal flux.Effects of the parameters on the transition between TEM and ITG instability are studied atρ=0.24.It is found that TEM dominates in the scanning with individually changing R/LTe from 2.50 to 25.02 or the density gradient R/L_(n)from 1.38 to 13.76.Meanwhile,the electron-ion temperature ratio T_(e)/T_(i)is found to destabilize TEM,the effect of Teis more sensitive than that of T_(i).The dominant instability diagrams in the(R/L_(Te),R/L_(Ti))plane at different T_(e)/T_(i)and R/Lnare numerically obtained,which clearly show the parameter range of the dominant TEM or dominant ITG instability region.It is found that the dominant TEM region becomes narrower in the plane by decreasing R/L_(n)when T_(e)/T_(i)>0.5.展开更多
Stroke patients with hemiplegia exhibit flexor spasms in the upper limb and extensor spasms in the lower limb, and their movement patterns vary greatly. Constraint-induced movement therapy is an upper limb rehabilitat...Stroke patients with hemiplegia exhibit flexor spasms in the upper limb and extensor spasms in the lower limb, and their movement patterns vary greatly. Constraint-induced movement therapy is an upper limb rehabilitation technique used in stroke patients with hemiplegia; however, studies of lower extremity rehabilitation are scarce. In this study, stroke patients with lower limb hemiplegia underwent conventional Bobath therapy for 4 weeks as baseline treatment, followed by constraint-induced movement therapy for an additional 4 weeks. The 10-m maximum walking speed and Berg balance scale scores significantly improved following treatment, and lower extremity motor function also improved. The results of functional MRI showed that constraint-induced movement therapy alleviates the reduction in cerebral functional activation in patients, which indicates activation of functional brain regions and a significant increase in cerebral blood perfusJon. These results demonstrate that constraint-induced movement therapy promotes brain functional reorganization in stroke patients with lower limb hemiplegia.展开更多
Reducing nitrogen to ammonia with solar energy has become a wide concern when it comes to photocatalysis research.It is considered to be one of the more promising alternate options for the conventional Haber-Bosch cyc...Reducing nitrogen to ammonia with solar energy has become a wide concern when it comes to photocatalysis research.It is considered to be one of the more promising alternate options for the conventional Haber-Bosch cycle.Herein,2D g-C_(3)N_(4)composites with modifying ultrathin sheet MnO_(2-x)were prepared and used as nitrogen fixation photocatalyst.With the assistance of the nature of MnO_(2-x),the generation rate of NH_(3)reached 225 mmol g^(-1)h^(-1),which is more than twice over the rate of pristine 2D g-C_(3)N_(4)(107 mmol g^(-1)h^(-1)).The presence of ultrathin sheet MnO_(2-x)shortens the gap of the carriers to the surface of photocatalyst.Thus the speed of electron transfer gets increased.Besides,the construction of Z-scheme heterojunction boosts the separation and migration of photogenerated carriers.As a result,the nitrogen reduction reaction(NRR)performance gets enhanced.The work may provide an example of promoting the NRR performance of non-metallic compound.展开更多
In this work,the anomalous transport driven by the ion temperature gradient instability is investigated in an anisotropic deuterium-tritium(D-T)plasma.The anisotropic factorα,defined as the ratio of perpendicular tem...In this work,the anomalous transport driven by the ion temperature gradient instability is investigated in an anisotropic deuterium-tritium(D-T)plasma.The anisotropic factorα,defined as the ratio of perpendicular temperature to parallel temperature,is introduced to describe the temperature anisotropy in the equilibrium distribution function.The linear dispersion relation in local kinetic limit is derived,and then numerically evaluated to study the dependence of mode frequency on the anisotropic factorαof D and the fraction of T particleεTby choosing three sets of typical parameters,denoted as the cyclone base case,ITER and CFETR cases.Based on the linear results,the mixing length model approximation is adopted to analyze the quasi-linear particle and energy fluxes for D and T.It is found that choosing smallαand largeεTis beneficial for the confinement of particle and energy for D and T.This work may be helpful for the estimation of turbulent transport level in the ITER and CFETR devices.展开更多
Arbuscular mycorrhizal(AM)fungi reside in the rhizosphere and form mutualistic associations with plant roots.They promote photosynthesis,improve stress resistance,and induce secondary metabolite biosynthesis in host m...Arbuscular mycorrhizal(AM)fungi reside in the rhizosphere and form mutualistic associations with plant roots.They promote photosynthesis,improve stress resistance,and induce secondary metabolite biosynthesis in host medicinal plants.The AM fungi that are symbiotic with medicinal plants comprise a wide array of species and have abundant germplasm resources.Though research on the AM fungi in medicinal plants began relatively recently,it has nonetheless become an investigative hot spot.Several scholars have explored the diversity and the growth-promoting effects of mycorrhizal fungi in hundreds of medicinal plants.Current research on symbiotic AM fungi in medicinal plants has focused mainly on the effects of inoculating host plants with symbiotic mycorrhizal fungi.However,research on the symbiotic AM fungi in medicinal plants continues to expand,and further study is required to determine the mechanisms by which AM fungi interact with host plants.This paper introduces the diversity of symbiotic AM fungi of medicinal plants and the effects of AM fungi on rhizosphere soil of medicinal plants,including soil structure,microbiota,enzyme activities,etc.This review focuses on the effects of AM fungi on medicinal plants,including antioxidant enzyme systems,drought resistance,nutrient absorption profiles of macroand micronutrients,accumulation of secondary metabolites such as terpenes,phenolic compounds,and nitrogenous compounds,and prevention of diseases.This review is expected to provide a reference for the application of AM fungi in medicinal plant cultivation,biological control,resource conservation,and the sustainable development of the traditional Chinese medicine industry.展开更多
The interaction between a magnetized ion and two monochromatic shear Alfvtn waves propagating obliquely to an ambient magnetic field is investigated both analytically and numerically. According to the Hamiltonian of t...The interaction between a magnetized ion and two monochromatic shear Alfvtn waves propagating obliquely to an ambient magnetic field is investigated both analytically and numerically. According to the Hamiltonian of this system, the invariant of motion at the lowest order and the half-island widths at the corresponding resonances are obtained analytically using the Lie transformation method. It is shown that these theoretical results agree with the numerical ones from the Poincare surface of section. The regular motions from the invariant and the transition to stochasticity due to resonance overlapping are demonstrated. Compared to the case of a single wave, there may be a lower stochastic threshold in the multiple-wave problem.展开更多
Soil moisture is directly related to the amount of irrigation in agriculture and influences the yield of crops.Accordingly,a soil moisture sensor is an important tool for measuring soil moisture content.In this study,...Soil moisture is directly related to the amount of irrigation in agriculture and influences the yield of crops.Accordingly,a soil moisture sensor is an important tool for measuring soil moisture content.In this study,the previous research conducted in recent 2-3 decades on soil moisture sensors was reviewed and the principles of commonly used soil moisture sensor and their various applications were summarized.Furthermore,the advantages,disadvantages,and influencing factors of various measurement methods employed were compared and analyzed.The improvements were presented by several scholars have established the major applications and performance levels of soil moisture sensors,thereby setting the course for future development.These studies indicated that soil moisture sensors in the future should be developed to achieve high-precision,low-cost,non-destructive,automated,and highly integrated systems.Also,it was indicated that future studies should involve the development of specialized sensors for different applications and scenarios.This review research aimed to provide a certain reference for application departments and scientific researchers in the process of selecting soil moisture sensor products and measuring soil moisture.展开更多
Optimizing photocatalytic CO_(2)reduction with simultaneous pollutant degradation is highly desired.However,the photocatalytic efficiency is restricted by the unmatched redox ability,high carriers’recombination rate,...Optimizing photocatalytic CO_(2)reduction with simultaneous pollutant degradation is highly desired.However,the photocatalytic efficiency is restricted by the unmatched redox ability,high carriers’recombination rate,and lack of reactive sites of the present photocatalysts.Herein,the CuInZnS-Ti_(3)C_(2)T_(x)hybrid with matched redox ability and suitable CO_(2)adsorption property was rationally synthesized.The nucleation and growth process of CuInZnS was interfered by the addition of Ti_(3)C_(2)T_(x)with a negative charge,resulting in thinner nanosheets and richer reactive sites.Besides,the Schottky heterojunction built in the hybrid simultaneously improved the photoexcited charge transfer property,sunlight absorption range,and CO_(2)adsorption ability.Consequently,upon exposure to sunlight,CuInZnS-Ti_(3)C_(2)T_(x)exhibited an efficient photocatalytic CO_(2)reduction performance(10.2μmol·h^(−1)·g^(−1))with synergetic tetracycline degradation,obviously higher than that of pure CuInZnS.Based on the combination of theoretical calculation and experimental characterization,the photocatalytic mechanism was investigated comprehensively.This work offers a reference for the remission of worldwide energy shortage and environmental pollution problems.展开更多
Intermittent demand refers to the specific demand pattern with frequent periods of zero demand.It occurs in a variety of industries including industrial equipment,automotive and specialty chemicals.In some industries ...Intermittent demand refers to the specific demand pattern with frequent periods of zero demand.It occurs in a variety of industries including industrial equipment,automotive and specialty chemicals.In some industries or some sectors of industry,even majority of products are in intermittent demand pattern.Due to the usually small and highly variable demand sizes,accurate forecasting of intermittent demand has always been challenging.However,accurate forecasting of intermittent demand is critical to the effective inventory management.In this study we present a band new method-modified TSB method for the forecasting of intermittent demand.The proposed method is based on TSB method,and adopts similar strategy,which has been used in m SBA method to update demand interval and demand occurrence probability when current demand is zero.To evaluate the proposed method,16289 daily demand records from the M5 data set that are identified as intermittent demands according to two criteria,and an empirical data set consisting three years’monthly demand history of 1718 medicine products are used.The proposed m TSB method achieves the best results on MASE and RMASE among all comparison methods on the M5 data set.On the empirical data set,the study shows that m TSB attains an ME of 0.07,which is the best among six comparison methods.Additionally,on the MSE measurement,m TSB shows a similar result as SES,both of which outperform other methods.展开更多
This paper investigates the linkage of returns and volatilities between the United States and Chinese stock markets from January 2010 to March 2020.We use the dynamic conditional correlation(DCC)and asymmetric Baba–E...This paper investigates the linkage of returns and volatilities between the United States and Chinese stock markets from January 2010 to March 2020.We use the dynamic conditional correlation(DCC)and asymmetric Baba–Engle–Kraft–Kroner(BEKK)GARCH models to calculate the time-varying correlations of these two markets and examine the return and volatility spillover effects between these two markets.The empirical results show that there are only unidirectional return spillovers from the U.S.stock market to the Chinese stock market.The U.S.stock market has a consistently positive spillover to China’s next day’s morning trading,but its impact on China’s next day’s afternoon trading appears to be insignificant.This finding implies that information in the U.S.stock market impacts the performance of the Chinese stock market differently in distinct semi-day trading.Moreover,with respect to the volatility,there are significant bidirectional spillover effects between these two markets.展开更多
基金supported by the National Natural Science Foundation of China (No.51874179,52005240 and 52164045)the Young Talent Program of Major Disciplines of Academic and Technical Leaders in Jiangxi Province (No.20212BCJ23028)。
文摘Friction stir welding of dissimilar Al/Mg thick plates still faces severe challenges, such as poor formability, formation of thick intermetallic compounds, and low joint strength. In this work, two joint configurations, namely inclined butt(conventional butt) and serrated interlocking(innovative butt), are proposed for improving weld formation and joint quality. The results show that a continuous and straight intermetallic compound layer appears at the Mg side interface in conventional butt joint, and the maximum average thickness reaches about 60.1 μm.Additionally, the Mg side interface also partially melts, forming a eutectic structure composed of Mg solid solution and Al_(12)Mg_(17) phase.For the innovative butt joint, the Mg side interface presents the curved interlocking feature, and intermetallic compounds can be reduced to less than 10 μm. The joint strength of innovative butt joint is more than three times that of conventional butt joint. This is due to the interlocking effect and thin intermetallic compounds in the innovative joint.
基金supported by the National Natural Science Foundation of China(Nos.52274292 and 51874046)the Outstanding Youth Foundation of Hubei Province,China(No.2020CFA090)the Young Topnotch Talent Cultivation Program of Hubei Province,China.
文摘Tin-based materials are very attractive anodes because of their high theoretical capacity,but their rapid capacity fading from volume expansions limits their practical applications during alloying and dealloying processes.Herein,the improved binder-free tin-copper intermetallic/carbon nanotubes(Cu6Sn5/CNTs)alloy thin-film electrodes are directly fabricated through efficient in situ electrodeposition from the leaching solution of treated waste-printed circuit boards(WPCBs).The characterization results show that the easily agglomerated Cu6Sn5 alloy nanoparticles are uniformly dispersed across the three-dimensional network when the CNTs concentration in the electrodeposition solution is maintained at 0.2 g·L−1.Moreover,the optimal Cu6Sn5/CNTs-0.2 alloy thin-film electrode can not only provide a decent discharge specific capacity of 458.35 mAh·g^(−1)after 50 cycles at 100 mA·g^(−1)within capacity retention of 82.58%but also deliver a relatively high reversible specific capacity of 518.24,445.52,418.18,345.33,and 278.05 mAh·g^(−1)at step-increased current density of 0.1,0.2,0.5,1.0,and 2.0 A·g^(−1),respectively.Therefore,the preparation process of the Cu6Sn5/CNTs-0.2 alloy thin-film electrode with improved electrochemical performance may provide a cost-effective strategy for the resource utilization of WPCBs to fabricate anode materials for lithium-ion batteries.
基金supported by the National MCF Energy R&D Program of China(Nos.2019YFE03060000,2019YFE03050000 and 2019YFE03020004)National Natural Science Foundation of China(Nos.12005063 and 11875131)+1 种基金Users with Excellence Program of Hefei Science Center CAS(Nos.2020HSC-UE011 and 2021HSC-UE015)Anhui Provincial Natural Science Foundation(No.2008085Jo4)。
文摘The parameter dependence of transition between electrostatic instabilities is studied using gyrokinetic simulation based on a real discharge of steady-state scenario in the Experimental Advanced Superconducting Tokamak.The scan of radial locations shows that trapped electron mode(TEM)dominates around the core while the ion temperature gradient mode(ITG)simultaneously dominates outside.The maximum growth rate of TEM appears aroundρ=0.24,where the maximum electron temperature gradient R/LTelocates,ρis the normalized poloidal flux.Effects of the parameters on the transition between TEM and ITG instability are studied atρ=0.24.It is found that TEM dominates in the scanning with individually changing R/LTe from 2.50 to 25.02 or the density gradient R/L_(n)from 1.38 to 13.76.Meanwhile,the electron-ion temperature ratio T_(e)/T_(i)is found to destabilize TEM,the effect of Teis more sensitive than that of T_(i).The dominant instability diagrams in the(R/L_(Te),R/L_(Ti))plane at different T_(e)/T_(i)and R/Lnare numerically obtained,which clearly show the parameter range of the dominant TEM or dominant ITG instability region.It is found that the dominant TEM region becomes narrower in the plane by decreasing R/L_(n)when T_(e)/T_(i)>0.5.
文摘Stroke patients with hemiplegia exhibit flexor spasms in the upper limb and extensor spasms in the lower limb, and their movement patterns vary greatly. Constraint-induced movement therapy is an upper limb rehabilitation technique used in stroke patients with hemiplegia; however, studies of lower extremity rehabilitation are scarce. In this study, stroke patients with lower limb hemiplegia underwent conventional Bobath therapy for 4 weeks as baseline treatment, followed by constraint-induced movement therapy for an additional 4 weeks. The 10-m maximum walking speed and Berg balance scale scores significantly improved following treatment, and lower extremity motor function also improved. The results of functional MRI showed that constraint-induced movement therapy alleviates the reduction in cerebral functional activation in patients, which indicates activation of functional brain regions and a significant increase in cerebral blood perfusJon. These results demonstrate that constraint-induced movement therapy promotes brain functional reorganization in stroke patients with lower limb hemiplegia.
基金supported by National Natural Science Foundation of China(21776118,21808090)Natural Science Foundation of Jiangsu Province(BK20190981)+3 种基金Jiangsu Fund for Distinguished Young Scientists(BK20190045)China Postdoctoral Science Foundation(2019M661765)High-tech Research Key laboratory of Zhenjiang(SS2018002)A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions,the high-performance computing platform of Jiangsu University。
文摘Reducing nitrogen to ammonia with solar energy has become a wide concern when it comes to photocatalysis research.It is considered to be one of the more promising alternate options for the conventional Haber-Bosch cycle.Herein,2D g-C_(3)N_(4)composites with modifying ultrathin sheet MnO_(2-x)were prepared and used as nitrogen fixation photocatalyst.With the assistance of the nature of MnO_(2-x),the generation rate of NH_(3)reached 225 mmol g^(-1)h^(-1),which is more than twice over the rate of pristine 2D g-C_(3)N_(4)(107 mmol g^(-1)h^(-1)).The presence of ultrathin sheet MnO_(2-x)shortens the gap of the carriers to the surface of photocatalyst.Thus the speed of electron transfer gets increased.Besides,the construction of Z-scheme heterojunction boosts the separation and migration of photogenerated carriers.As a result,the nitrogen reduction reaction(NRR)performance gets enhanced.The work may provide an example of promoting the NRR performance of non-metallic compound.
基金supported by the National MCF Energy R&D Program of China(No.2019YFE03060000)National Natural Science Foundation of China(Nos.12005063,12175228,11875131 and 11675053)。
文摘In this work,the anomalous transport driven by the ion temperature gradient instability is investigated in an anisotropic deuterium-tritium(D-T)plasma.The anisotropic factorα,defined as the ratio of perpendicular temperature to parallel temperature,is introduced to describe the temperature anisotropy in the equilibrium distribution function.The linear dispersion relation in local kinetic limit is derived,and then numerically evaluated to study the dependence of mode frequency on the anisotropic factorαof D and the fraction of T particleεTby choosing three sets of typical parameters,denoted as the cyclone base case,ITER and CFETR cases.Based on the linear results,the mixing length model approximation is adopted to analyze the quasi-linear particle and energy fluxes for D and T.It is found that choosing smallαand largeεTis beneficial for the confinement of particle and energy for D and T.This work may be helpful for the estimation of turbulent transport level in the ITER and CFETR devices.
基金This work was supported by the National Natural Science Foundation of China(31960272)Basic research fund of Guangxi Academy of Sciences(CQZE-1909)the Guangxi Scientific and Technological Project(Guike AB18126065).
文摘Arbuscular mycorrhizal(AM)fungi reside in the rhizosphere and form mutualistic associations with plant roots.They promote photosynthesis,improve stress resistance,and induce secondary metabolite biosynthesis in host medicinal plants.The AM fungi that are symbiotic with medicinal plants comprise a wide array of species and have abundant germplasm resources.Though research on the AM fungi in medicinal plants began relatively recently,it has nonetheless become an investigative hot spot.Several scholars have explored the diversity and the growth-promoting effects of mycorrhizal fungi in hundreds of medicinal plants.Current research on symbiotic AM fungi in medicinal plants has focused mainly on the effects of inoculating host plants with symbiotic mycorrhizal fungi.However,research on the symbiotic AM fungi in medicinal plants continues to expand,and further study is required to determine the mechanisms by which AM fungi interact with host plants.This paper introduces the diversity of symbiotic AM fungi of medicinal plants and the effects of AM fungi on rhizosphere soil of medicinal plants,including soil structure,microbiota,enzyme activities,etc.This review focuses on the effects of AM fungi on medicinal plants,including antioxidant enzyme systems,drought resistance,nutrient absorption profiles of macroand micronutrients,accumulation of secondary metabolites such as terpenes,phenolic compounds,and nitrogenous compounds,and prevention of diseases.This review is expected to provide a reference for the application of AM fungi in medicinal plant cultivation,biological control,resource conservation,and the sustainable development of the traditional Chinese medicine industry.
基金supported by National Natural Science Foundation of China under Grant Nos. 11075140, 11205060 and 11405058the National Magnetic Confinement Fusion Science Program of China under Grant Nos. 2013GB106002 and 2015GB110005
文摘The interaction between a magnetized ion and two monochromatic shear Alfvtn waves propagating obliquely to an ambient magnetic field is investigated both analytically and numerically. According to the Hamiltonian of this system, the invariant of motion at the lowest order and the half-island widths at the corresponding resonances are obtained analytically using the Lie transformation method. It is shown that these theoretical results agree with the numerical ones from the Poincare surface of section. The regular motions from the invariant and the transition to stochasticity due to resonance overlapping are demonstrated. Compared to the case of a single wave, there may be a lower stochastic threshold in the multiple-wave problem.
基金This work was supported by the National Natural Science Foundation of China(Grant No.31801669)the Research and Development Program of Shandong Province(Grant No.2019GSF111035)the Government-sponsored Visiting Scholar Research Program.
文摘Soil moisture is directly related to the amount of irrigation in agriculture and influences the yield of crops.Accordingly,a soil moisture sensor is an important tool for measuring soil moisture content.In this study,the previous research conducted in recent 2-3 decades on soil moisture sensors was reviewed and the principles of commonly used soil moisture sensor and their various applications were summarized.Furthermore,the advantages,disadvantages,and influencing factors of various measurement methods employed were compared and analyzed.The improvements were presented by several scholars have established the major applications and performance levels of soil moisture sensors,thereby setting the course for future development.These studies indicated that soil moisture sensors in the future should be developed to achieve high-precision,low-cost,non-destructive,automated,and highly integrated systems.Also,it was indicated that future studies should involve the development of specialized sensors for different applications and scenarios.This review research aimed to provide a certain reference for application departments and scientific researchers in the process of selecting soil moisture sensor products and measuring soil moisture.
基金the National Natural Science Foundation of China(Nos.21801092,U1804138,and 22006057)the Program for the Development of Science and Technology of Jilin Province(Nos.20210101409JC and 20200801040GH)+4 种基金the Program for Science&Technology Innovative Research Team at University of Henan Province(No.20IRTSTHN007)the Science&Technology Innovation Talents in Universities of Henan Province(No.22HASTIT028)the Science and Technology Research Project of Henan Province(Nos.202102210055,212102210128,and 202102310615)Henan Postdoctoral Foundation(No.202003013)the General project of Chinese postdoctoral program(No.2020M672263).
文摘Optimizing photocatalytic CO_(2)reduction with simultaneous pollutant degradation is highly desired.However,the photocatalytic efficiency is restricted by the unmatched redox ability,high carriers’recombination rate,and lack of reactive sites of the present photocatalysts.Herein,the CuInZnS-Ti_(3)C_(2)T_(x)hybrid with matched redox ability and suitable CO_(2)adsorption property was rationally synthesized.The nucleation and growth process of CuInZnS was interfered by the addition of Ti_(3)C_(2)T_(x)with a negative charge,resulting in thinner nanosheets and richer reactive sites.Besides,the Schottky heterojunction built in the hybrid simultaneously improved the photoexcited charge transfer property,sunlight absorption range,and CO_(2)adsorption ability.Consequently,upon exposure to sunlight,CuInZnS-Ti_(3)C_(2)T_(x)exhibited an efficient photocatalytic CO_(2)reduction performance(10.2μmol·h^(−1)·g^(−1))with synergetic tetracycline degradation,obviously higher than that of pure CuInZnS.Based on the combination of theoretical calculation and experimental characterization,the photocatalytic mechanism was investigated comprehensively.This work offers a reference for the remission of worldwide energy shortage and environmental pollution problems.
基金supported in part by XJTLU laboratory for intelligent computation and financial technology through XJTLU Key Programme Special Fund(KSFeP-02 and KSF-E-21)
文摘Intermittent demand refers to the specific demand pattern with frequent periods of zero demand.It occurs in a variety of industries including industrial equipment,automotive and specialty chemicals.In some industries or some sectors of industry,even majority of products are in intermittent demand pattern.Due to the usually small and highly variable demand sizes,accurate forecasting of intermittent demand has always been challenging.However,accurate forecasting of intermittent demand is critical to the effective inventory management.In this study we present a band new method-modified TSB method for the forecasting of intermittent demand.The proposed method is based on TSB method,and adopts similar strategy,which has been used in m SBA method to update demand interval and demand occurrence probability when current demand is zero.To evaluate the proposed method,16289 daily demand records from the M5 data set that are identified as intermittent demands according to two criteria,and an empirical data set consisting three years’monthly demand history of 1718 medicine products are used.The proposed m TSB method achieves the best results on MASE and RMASE among all comparison methods on the M5 data set.On the empirical data set,the study shows that m TSB attains an ME of 0.07,which is the best among six comparison methods.Additionally,on the MSE measurement,m TSB shows a similar result as SES,both of which outperform other methods.
文摘This paper investigates the linkage of returns and volatilities between the United States and Chinese stock markets from January 2010 to March 2020.We use the dynamic conditional correlation(DCC)and asymmetric Baba–Engle–Kraft–Kroner(BEKK)GARCH models to calculate the time-varying correlations of these two markets and examine the return and volatility spillover effects between these two markets.The empirical results show that there are only unidirectional return spillovers from the U.S.stock market to the Chinese stock market.The U.S.stock market has a consistently positive spillover to China’s next day’s morning trading,but its impact on China’s next day’s afternoon trading appears to be insignificant.This finding implies that information in the U.S.stock market impacts the performance of the Chinese stock market differently in distinct semi-day trading.Moreover,with respect to the volatility,there are significant bidirectional spillover effects between these two markets.