The size effects were experimentally investigated and the underlying mechanism was analyzed.The results reveal that,as the specimen size increases,the interconnectivity of macropores slightly decreases.This in turn co...The size effects were experimentally investigated and the underlying mechanism was analyzed.The results reveal that,as the specimen size increases,the interconnectivity of macropores slightly decreases.This in turn constrains the diffusion of CO_(2) and moisture in the specimens,resulting in an increase in the discrepancy between the internal and external carbonation degrees.An increase in cement paste thickness simultaneously decreases the quantity,average size,and interconnectivity of macropores,lowering the diffusion efficacy of CO_(2) and moisture and exacerbating the overall heterogeneity in carbonation.Moreover,the gradual blockage of macropores leads to the emergence of localized ‘occluded zones’ with much lower carbonation degree.The reduction in aggregate size significantly alters the average diameter and connectivity of macropores,leading to notable change to overall non-uniformity.This study provides insight into improving the CO_(2) curing effect of pervious concrete products and developing uniform curing methods.展开更多
The application of segmental semi-solid thixoforming of magnesium alloys is confined due to the dimensional distinction existing in solid particles of the alloy billet from edge to center zones. In the present study, ...The application of segmental semi-solid thixoforming of magnesium alloys is confined due to the dimensional distinction existing in solid particles of the alloy billet from edge to center zones. In the present study, the effects of Sm addition on the microstructural evolution of Mg-6Zn-0.4Zr and Mg-6Zn-4Sm-0.4Zr alloys by semi-solid isothermal heat treatment were investigated, to obtain optimum semi-solid microstructures for the subsequently thixoforming. The results indicate that the grains of the Sm-bearing alloy are evidently refined and gradually evolve from dendritic to globular and elliptic particles. In addition, the distinctly dimensional effect of the Mg-6Zn-0.4Zr alloy is eliminated with 4% Sm addition; the particle sizes in all zones from center to the edge of the billet are almost identical. With the increment of isothermal heat treatment temperature, the dendritic microstructures completely disappear, and meanwhile, the irregular and globular particles gradually form. The size, morphology and the distribution of solid particles mainly depend on the formation and permeation of the liquid phase in the process of isothermal heat treatment. As the isothermal temperature increases from 570 °C to 610 °C, the average size and shape factor of solid particles of both the alloys with and without Sm addition gradually decrease while the liquid fraction gradually increases.展开更多
By the fractal dimension method, the polaron properties in cylindrical GaAs/AlxGa1-xAs core-shell nanowire are explored. In this study, the polaron effects in GaAs/AlxGa1-xAs core-shell nanowire at different values of...By the fractal dimension method, the polaron properties in cylindrical GaAs/AlxGa1-xAs core-shell nanowire are explored. In this study, the polaron effects in GaAs/AlxGa1-xAs core-shell nanowire at different values of shell width and aluminum concentration are discussed. The polaron binding energy, polaron mass shift and fractal dimension parameter are numerically worked out each as a function of core radius. The calculation results show that the binding energy and mass shift of the polaron first increase and then decrease as the core radius increases, forming their corresponding maximum values for different aluminum concentrations at a given shell width. Polaron problems in the cylindrical GaAs/AlxGa1-xAs core-shell nanowire are solved simply by using the fractal dimension method to avoid complex and lengthy calculations.展开更多
The giant magneto-impedance（GMI）effect of amorphous wire was analyzed theoretically.The amorphous wire had strong GMI effect in the stimulation of sharp pulse of 680kHz and18 mV.A pulse generator was designed to pro...The giant magneto-impedance（GMI）effect of amorphous wire was analyzed theoretically.The amorphous wire had strong GMI effect in the stimulation of sharp pulse of 680kHz and18 mV.A pulse generator was designed to provide high frequency pulse to a magnetic impedance（MI）element.The induced voltage on the pickup coil wound on the amorphous wire was sampled and held with a detect circuit using analog switch.A stable magnetic sensor was constructed.A three-dimension micro magnetic field detector was designed with a central controller MSP430F449.High stability and sensitivity were obtained in the MI sensor with the detect circuit.Experiment results showed that the resolution of the detector was 1nT in the full scale of±2 Oe and the detector worked stably from the room temperature to about 80℃.A small ferromagnetic target was detected by the three-dimension detector in laboratory environment without magnetic shielding.The target moving direction was ascertained with the wave shape of axis parallel in that direction.展开更多
The catalytic system is investigated in a computer chromatography. The sorbent represents the nanostructure composite with hardpolymer electrolyt. As the nanostructure polymeric system, it used dendrimer who are absor...The catalytic system is investigated in a computer chromatography. The sorbent represents the nanostructure composite with hardpolymer electrolyt. As the nanostructure polymeric system, it used dendrimer who are absorbed on a surface with formation of monolayer. In chromatography column watch dimensional effect. The size of a particle carries out a role of temperature. In the article, investigate solvatation and dimensional effect reaction self-assembling gas dimmers. Distance critical radius H＋ transfer define equation： rcr = 2rs. Reaction accompaniment transfer energy. Transfer energy realize on exchange-resonanse mechanism.展开更多
A quantized Hall conductance(not conductivity)in three dimensions has been searched for more than 30 years.Here we explore it in 3D topological nodal-ring semimetals,by employing a minimal model describing the essenti...A quantized Hall conductance(not conductivity)in three dimensions has been searched for more than 30 years.Here we explore it in 3D topological nodal-ring semimetals,by employing a minimal model describing the essential physics.In particular,the bulk topology can be captured by a momentum-dependent winding number,which confines the drumhead surface states in a specific momentum region.This confinement leads to a surface quantum Hall conductance in a specific energy window in this 3D system.The winding number for the drumhead surface states and Chern number for their quantum Hall effect form a two-fold topological hierarchy.We demonstrate the one-to-one correspondence between the momentum-dependent winding number and wavefunction of the drumhead surface states.More importantly,we stress that breaking chiral symmetry is necessary for the quantum Hall effect of the drumhead surface states.The analytic theory can be verified numerically by the Kubo formula for the Hall conductance.We propose an experimental setup to distinguish the surface and bulk quantum Hall effects.The theory will be useful for ongoing explorations on nodal-ring semimetals.展开更多
To achieve a characterization method for the gate delay library used in block based statistical static timing analysis with neither unacceptably poor accuracy nor forbiddingly high cost,we found that general-purpose g...To achieve a characterization method for the gate delay library used in block based statistical static timing analysis with neither unacceptably poor accuracy nor forbiddingly high cost,we found that general-purpose gate delay models are useful as intermediaries between the circuit simulation data and the gate delay models in required forms.In this work,two gate delay models for process variation considering different driving and loading conditions are proposed.From the testing results,these two models,especially the one that combines effective dimension reduction（EDR） from statistics society with comprehensive gate delay models,offer good accuracy with low characterization cost,and they are thus competent for use in statistical timing analysis（SSTA）.In addition, these two models have their own value in other SSTA techniques.展开更多
基金Funded by the National Natural Science Foundation of China (No.22203066)the 6th Young Elite Scientist Sponsorship Program by China Association for Science and Technology (No.2020QNRC001)。
文摘The size effects were experimentally investigated and the underlying mechanism was analyzed.The results reveal that,as the specimen size increases,the interconnectivity of macropores slightly decreases.This in turn constrains the diffusion of CO_(2) and moisture in the specimens,resulting in an increase in the discrepancy between the internal and external carbonation degrees.An increase in cement paste thickness simultaneously decreases the quantity,average size,and interconnectivity of macropores,lowering the diffusion efficacy of CO_(2) and moisture and exacerbating the overall heterogeneity in carbonation.Moreover,the gradual blockage of macropores leads to the emergence of localized ‘occluded zones’ with much lower carbonation degree.The reduction in aggregate size significantly alters the average diameter and connectivity of macropores,leading to notable change to overall non-uniformity.This study provides insight into improving the CO_(2) curing effect of pervious concrete products and developing uniform curing methods.
基金supported by the National Natural Science Foundations of China(51464032)the National Basic Research Program of China(grant No.2010CB635106)
文摘The application of segmental semi-solid thixoforming of magnesium alloys is confined due to the dimensional distinction existing in solid particles of the alloy billet from edge to center zones. In the present study, the effects of Sm addition on the microstructural evolution of Mg-6Zn-0.4Zr and Mg-6Zn-4Sm-0.4Zr alloys by semi-solid isothermal heat treatment were investigated, to obtain optimum semi-solid microstructures for the subsequently thixoforming. The results indicate that the grains of the Sm-bearing alloy are evidently refined and gradually evolve from dendritic to globular and elliptic particles. In addition, the distinctly dimensional effect of the Mg-6Zn-0.4Zr alloy is eliminated with 4% Sm addition; the particle sizes in all zones from center to the edge of the billet are almost identical. With the increment of isothermal heat treatment temperature, the dendritic microstructures completely disappear, and meanwhile, the irregular and globular particles gradually form. The size, morphology and the distribution of solid particles mainly depend on the formation and permeation of the liquid phase in the process of isothermal heat treatment. As the isothermal temperature increases from 570 °C to 610 °C, the average size and shape factor of solid particles of both the alloys with and without Sm addition gradually decrease while the liquid fraction gradually increases.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.10574011 and 10974017)
文摘By the fractal dimension method, the polaron properties in cylindrical GaAs/AlxGa1-xAs core-shell nanowire are explored. In this study, the polaron effects in GaAs/AlxGa1-xAs core-shell nanowire at different values of shell width and aluminum concentration are discussed. The polaron binding energy, polaron mass shift and fractal dimension parameter are numerically worked out each as a function of core radius. The calculation results show that the binding energy and mass shift of the polaron first increase and then decrease as the core radius increases, forming their corresponding maximum values for different aluminum concentrations at a given shell width. Polaron problems in the cylindrical GaAs/AlxGa1-xAs core-shell nanowire are solved simply by using the fractal dimension method to avoid complex and lengthy calculations.
基金Supported by the National Natural Science Foundation of China(60874100)
文摘The giant magneto-impedance（GMI）effect of amorphous wire was analyzed theoretically.The amorphous wire had strong GMI effect in the stimulation of sharp pulse of 680kHz and18 mV.A pulse generator was designed to provide high frequency pulse to a magnetic impedance（MI）element.The induced voltage on the pickup coil wound on the amorphous wire was sampled and held with a detect circuit using analog switch.A stable magnetic sensor was constructed.A three-dimension micro magnetic field detector was designed with a central controller MSP430F449.High stability and sensitivity were obtained in the MI sensor with the detect circuit.Experiment results showed that the resolution of the detector was 1nT in the full scale of±2 Oe and the detector worked stably from the room temperature to about 80℃.A small ferromagnetic target was detected by the three-dimension detector in laboratory environment without magnetic shielding.The target moving direction was ascertained with the wave shape of axis parallel in that direction.
文摘The catalytic system is investigated in a computer chromatography. The sorbent represents the nanostructure composite with hardpolymer electrolyt. As the nanostructure polymeric system, it used dendrimer who are absorbed on a surface with formation of monolayer. In chromatography column watch dimensional effect. The size of a particle carries out a role of temperature. In the article, investigate solvatation and dimensional effect reaction self-assembling gas dimmers. Distance critical radius H＋ transfer define equation： rcr = 2rs. Reaction accompaniment transfer energy. Transfer energy realize on exchange-resonanse mechanism.
基金supported by the National Key R&D Program of China(2022YFA1403700)the Innovation Program for Quantum Science and Technology(2021ZD0302400)+3 种基金the National Natural Science Foundation of China(11925402,11534001,and 11974249)Guangdong province(2020KCXTD001 and 2016ZT06D348)the Natural Science Foundation of Shanghai(19ZR1437300)supported by Center for Computational Science and Engineering of SUSTech.
文摘A quantized Hall conductance(not conductivity)in three dimensions has been searched for more than 30 years.Here we explore it in 3D topological nodal-ring semimetals,by employing a minimal model describing the essential physics.In particular,the bulk topology can be captured by a momentum-dependent winding number,which confines the drumhead surface states in a specific momentum region.This confinement leads to a surface quantum Hall conductance in a specific energy window in this 3D system.The winding number for the drumhead surface states and Chern number for their quantum Hall effect form a two-fold topological hierarchy.We demonstrate the one-to-one correspondence between the momentum-dependent winding number and wavefunction of the drumhead surface states.More importantly,we stress that breaking chiral symmetry is necessary for the quantum Hall effect of the drumhead surface states.The analytic theory can be verified numerically by the Kubo formula for the Hall conductance.We propose an experimental setup to distinguish the surface and bulk quantum Hall effects.The theory will be useful for ongoing explorations on nodal-ring semimetals.
文摘To achieve a characterization method for the gate delay library used in block based statistical static timing analysis with neither unacceptably poor accuracy nor forbiddingly high cost,we found that general-purpose gate delay models are useful as intermediaries between the circuit simulation data and the gate delay models in required forms.In this work,two gate delay models for process variation considering different driving and loading conditions are proposed.From the testing results,these two models,especially the one that combines effective dimension reduction（EDR） from statistics society with comprehensive gate delay models,offer good accuracy with low characterization cost,and they are thus competent for use in statistical timing analysis（SSTA）.In addition, these two models have their own value in other SSTA techniques.
