The development and technical characteristics in different stages of supercritical (ultra-Supercritical) technology abroad are introduced in this paper. At the same time, according to the development trend of supercri...The development and technical characteristics in different stages of supercritical (ultra-Supercritical) technology abroad are introduced in this paper. At the same time, according to the development trend of supercritical (ultra-supercritical) technology, the corresponding revelations are given in this paper. That is: It is an inevitable choice to develop supercritical (ultra-supercritical) technology if we want to improve the thermal efficiency and heat efficiency.展开更多
The head-flow rate curve with double humps brings greater challenges to the stable operation of a pump-turbine in pump mode,and the present investigation aims to reveal the formation mechanisms behind it.We performed ...The head-flow rate curve with double humps brings greater challenges to the stable operation of a pump-turbine in pump mode,and the present investigation aims to reveal the formation mechanisms behind it.We performed unsteady simulations by applying a modified partially averaged Navier-Stokes(PANS)model and the double hump phenomenon was satisfactorily captured with relative errors within 3.87%by comparing the head with the experimental data.The results showed that the rotating stall occurred in the guide vane during both the first and second hump regions and induced the dominant pressure pulsation component with an oscillating frequency 11.7%times the runner rotation frequency.The reverse flow was observed due to the propagation of rotating stall cells in the guide vane,and the first hump was attributed to the vortex in the vaneless region,with a reduction in the runner's capacity for doing work as the reverse flow reached the blade trailing edge.The second hump was attributed to the flow separation near the leading edge of the runner blades,which extended to the runner outlet and interacted with the rotating stall cell,leading to a rapid extension of the reverse flow into the runner.This not only reduces the runner's capacity for doing work but also significantly increases the energy loss in the blade-to-blade flow passage near the runner exit.This study enhances the understanding of the flow mechanism in the hump region,which can provide insights into the suppression of unstable flows and runner optimization.展开更多
Accurate researches on the surface plasmon resonance(SPR)-based applications of chiral plasmonic metal nanoparticles(NPs)still remain a great challenge.Herein,a series of chiral plasmonic metal NPs,e.g.,chiral Au nano...Accurate researches on the surface plasmon resonance(SPR)-based applications of chiral plasmonic metal nanoparticles(NPs)still remain a great challenge.Herein,a series of chiral plasmonic metal NPs,e.g.,chiral Au nanorods(c-Au NRs),c-Au@Ag core–shell,and c-Au@TiO_(2) core–shell NRs,with different chiroptical activities have been produced.Plasmonic circular dichroism(PCD)bands of c-Au NRs can be precisely tailored by tuning the longitudinal SPR(LSPR)and amount of Au NRs as seeds.Besides,a shift of PCD bands within ultraviolet–visible–near infrared ray(UV–vis–NIR)region can also be achieved through the functionalization of a shell of another metal or semiconductor.Interestingly,chirality transfer from c-Au core to Ag shell leads to new PCD bands at the near-UV region.The tuning of PCD bands and chirality transfer are confirmed by our developed theoretical model.Developing chiral Au NRs-based chiral plasmonic nanomaterials with tunable chiroptical activities will be helpful to understand the structure-direct PCD and to extend circularly polarized-based applications.展开更多
Multiphase catalysis is used in many industrial processes;however,the reaction rate can be restricted by the low accessibility of gaseous reactants to the catalysts in water,especially for oxygen-dependent biocatalyti...Multiphase catalysis is used in many industrial processes;however,the reaction rate can be restricted by the low accessibility of gaseous reactants to the catalysts in water,especially for oxygen-dependent biocatalytic reactions.Despite the fact that solubility and diffusion rates of oxygen in many liquids(such as perfluorocarbon)are much higher than in water,multiphase reactions with a second liquid phase are still difficult to conduct,because the interaction efficiency between immiscible phases is extremely low.Herein,we report an efficient triphase biocatalytic system using oil core-silica shell oxygen nanocarriers.Such design offers the biocatalytic system an extremely large water-solid-oil triphase interfacial area and a short path required for oxygen diffusion.Moreover,the silica shell stabilizes the oil nanodroplets in water and prevents their aggregation.Using oxygen-dependent oxidase enzymatic reaction as an example,we demonstrate this efficient biocatalytic system for the oxidation of glucose,choline,lactate,and sucrose by substituting their corresponding oxidase counterparts.A rate enhancement by a factor of 10-30 is observed when the oxygen nanocarriers are introduced into reaction system.This strategy offers the opportunity to enhance the efficiency of other gaseous reactants involved in multiphase catalytic reactions.展开更多
文摘The development and technical characteristics in different stages of supercritical (ultra-Supercritical) technology abroad are introduced in this paper. At the same time, according to the development trend of supercritical (ultra-supercritical) technology, the corresponding revelations are given in this paper. That is: It is an inevitable choice to develop supercritical (ultra-supercritical) technology if we want to improve the thermal efficiency and heat efficiency.
基金supported by the National Natural Science Foundation of China(Grant No.52336001)the China Postdoctoral Science Foundation(Grant Nos.2022TQ0168,2023M731895)。
文摘The head-flow rate curve with double humps brings greater challenges to the stable operation of a pump-turbine in pump mode,and the present investigation aims to reveal the formation mechanisms behind it.We performed unsteady simulations by applying a modified partially averaged Navier-Stokes(PANS)model and the double hump phenomenon was satisfactorily captured with relative errors within 3.87%by comparing the head with the experimental data.The results showed that the rotating stall occurred in the guide vane during both the first and second hump regions and induced the dominant pressure pulsation component with an oscillating frequency 11.7%times the runner rotation frequency.The reverse flow was observed due to the propagation of rotating stall cells in the guide vane,and the first hump was attributed to the vortex in the vaneless region,with a reduction in the runner's capacity for doing work as the reverse flow reached the blade trailing edge.The second hump was attributed to the flow separation near the leading edge of the runner blades,which extended to the runner outlet and interacted with the rotating stall cell,leading to a rapid extension of the reverse flow into the runner.This not only reduces the runner's capacity for doing work but also significantly increases the energy loss in the blade-to-blade flow passage near the runner exit.This study enhances the understanding of the flow mechanism in the hump region,which can provide insights into the suppression of unstable flows and runner optimization.
基金supported by the National Natural Science Foundation of China(Nos.21902148,11774036,12174032,and 22071172)the National Key Research and Development Program of China(No.2017YFA0303400)+1 种基金the National Natural Science Foundation of China-Research Grant Council(No.11861161002)K.Y.W.acknowledges the support by the Patrick S.C.Poon endowed professorship.
文摘Accurate researches on the surface plasmon resonance(SPR)-based applications of chiral plasmonic metal nanoparticles(NPs)still remain a great challenge.Herein,a series of chiral plasmonic metal NPs,e.g.,chiral Au nanorods(c-Au NRs),c-Au@Ag core–shell,and c-Au@TiO_(2) core–shell NRs,with different chiroptical activities have been produced.Plasmonic circular dichroism(PCD)bands of c-Au NRs can be precisely tailored by tuning the longitudinal SPR(LSPR)and amount of Au NRs as seeds.Besides,a shift of PCD bands within ultraviolet–visible–near infrared ray(UV–vis–NIR)region can also be achieved through the functionalization of a shell of another metal or semiconductor.Interestingly,chirality transfer from c-Au core to Ag shell leads to new PCD bands at the near-UV region.The tuning of PCD bands and chirality transfer are confirmed by our developed theoretical model.Developing chiral Au NRs-based chiral plasmonic nanomaterials with tunable chiroptical activities will be helpful to understand the structure-direct PCD and to extend circularly polarized-based applications.
基金the National Key R&D Program of China(No.2019YFA0709200)the National Natural Science Foundation of China(Nos.21988102,51772198,21975171).
文摘Multiphase catalysis is used in many industrial processes;however,the reaction rate can be restricted by the low accessibility of gaseous reactants to the catalysts in water,especially for oxygen-dependent biocatalytic reactions.Despite the fact that solubility and diffusion rates of oxygen in many liquids(such as perfluorocarbon)are much higher than in water,multiphase reactions with a second liquid phase are still difficult to conduct,because the interaction efficiency between immiscible phases is extremely low.Herein,we report an efficient triphase biocatalytic system using oil core-silica shell oxygen nanocarriers.Such design offers the biocatalytic system an extremely large water-solid-oil triphase interfacial area and a short path required for oxygen diffusion.Moreover,the silica shell stabilizes the oil nanodroplets in water and prevents their aggregation.Using oxygen-dependent oxidase enzymatic reaction as an example,we demonstrate this efficient biocatalytic system for the oxidation of glucose,choline,lactate,and sucrose by substituting their corresponding oxidase counterparts.A rate enhancement by a factor of 10-30 is observed when the oxygen nanocarriers are introduced into reaction system.This strategy offers the opportunity to enhance the efficiency of other gaseous reactants involved in multiphase catalytic reactions.
