Since the special relativity can be viewed as the physics in an inverse Wick rotation of four-dimensional （4D） Euclid space, which is at almost equal footing with the 4D Riemann/Lobachevski space, there should be im...Since the special relativity can be viewed as the physics in an inverse Wick rotation of four-dimensional （4D） Euclid space, which is at almost equal footing with the 4D Riemann/Lobachevski space, there should be important physics in the inverse Wick rotation of 4D Riemann/Lobachevski space. Thus, there are three kinds of special relativity in de Sitter（dS）/Minkowski/anti-de Sitter（AdS） space at almost equal footing, respectively. There is an instanton tunnelling scenario in the Riemann-de Sitter case that may explain why A be positive and link with the multiverse.展开更多
Printed circuit boards（PCBs） contain many toxic substances as well as valuable metals, e.g., lead（Pb） and tin（Sn）. In this study, a novel technology, named supergravity, was used to separate different mass ratio...Printed circuit boards（PCBs） contain many toxic substances as well as valuable metals, e.g., lead（Pb） and tin（Sn）. In this study, a novel technology, named supergravity, was used to separate different mass ratios of Pb and Sn from Pb–Sn alloys in PCBs. In a supergravity field, the liquid metal phase can permeate from solid particles. Hence, temperatures of 200, 280, and 400°C were chosen to separate Pb and Sn from PCBs. The results depicted that gravity coefficient only affected the recovery rates of Pb and Sn, whereas it had little effect on the mass ratios of Pb and Sn in the obtained alloys. With an increase in gravity coefficient, the recovery values of Pb and Sn in each step of the separation process increased. In the single-step separation process, the mass ratios of Pb and Sn in Pb–Sn alloys were 0.55, 0.40, and 0.64 at 200, 280, and 400°C, respectively. In the two-step separation process, the mass ratios were 0.12 and 0.55 at 280 and 400°C, respectively. Further, the mass ratio was observed to be 0.76 at 400°C in the three-step separation process. This process provides an innovative approach to the recycling mechanism of Pb and Sn from PCBs.展开更多
A previous preon scenario for the standard model particles, based on unbroken supersymmetry, is applied to the problem of matter-antimatter asymmetry. Attention is paid to the fact that the asymmetric hydrogen atom—l...A previous preon scenario for the standard model particles, based on unbroken supersymmetry, is applied to the problem of matter-antimatter asymmetry. Attention is paid to the fact that the asymmetric hydrogen atom—like all atoms—can be described in terms of symmetric preons. Preons are created in the early universe. The matter-antimatter asymmetry is caused by stochastic correlations in charge density fluctuations of preons and antipreons and by the subsequent preon combinatorial mechanism to form quarks and leptons, and finally the three lightest elements. A tentative gravitino mass estimate is given based on minimal interference with nucleosynthesis. With local supersymmetry the scenario can be extended to supergravity.展开更多
We report an experimental study of the local temperature fluctuationsδT and heat transport in a partitioned supergravitational turbulent convection system.Due to the dynamics of zonal flow in the normal system withou...We report an experimental study of the local temperature fluctuationsδT and heat transport in a partitioned supergravitational turbulent convection system.Due to the dynamics of zonal flow in the normal system without partition walls,the probability density function(PDF)at a position in the mixing zone exhibits a downward bending shape,suggesting that the multi-plume clustering effect plays an important role.In partitioned system,zonal flow is suppressed and the PDFs indicate that the single-plume effect is dominant.Moreover,statistical analysis shows that the PDF ofδT is sensitive to supergravity.Additionally,the thermal spectra follow P(f)∼f^(-5) in the normal system,which is relevant to the zonal flow.The absolute value of the scaling exponent of P(f)and the scaling range become small in the partitioned system,which provides another evidence for the influence of zonal flow on the energy cascade.Further,heat transfer enhancement is found in the partitioned system,which may result from zonal flow being restricted and then facilitating the radial movement of thermal plumes to the opposite conducting cylinder.This work may provide insights into the flow and heat transport control of some engineering and geophysical flows.展开更多
In the current work,we investigated hydrogen/air flame propagation under supergravity conditions.Results show that when gravity is in the same/opposite direction as flame propagation,it leads to acceleration/decelerat...In the current work,we investigated hydrogen/air flame propagation under supergravity conditions.Results show that when gravity is in the same/opposite direction as flame propagation,it leads to acceleration/deceleration of the flame,and that such an effect could substantially modify the flame propagation and structure at high gravity levels.Furthermore,for the absolute and relative flame propagation speeds,the gravity-affected flame speed shows opposite trends as the absolute flame speed is more affected by the local induced flow field,while the relative flame speeds are controlled by the super-adiabatic or sub-adiabatic flame temperature.The gravity-affected thermal and chemical flame structures are also examined through the influence of the mixture equivalence ratio,pressure,and flame stretch.展开更多
Investigating the microstructures and properties of gradient materials has been regarded as a promising way to accelerate the identification of optimal compositions for applications. Herein, a supergravity method is a...Investigating the microstructures and properties of gradient materials has been regarded as a promising way to accelerate the identification of optimal compositions for applications. Herein, a supergravity method is applied to prepare the graded entropic alloys Al-Zn-Li-Mg-Cu. Through carefully optimizing the experimental conditions, the graded microstructures and hardness values appear after the supergravity technique. The morphology of the alloy significantly changes from the bulk intermetallics to eutectic structures along the supergravity force direction, which results from the crushed and graded aluminum oxide combined with the extremelystrong force. The results show that with this supergravity method, a performance-enhanced alloy can potentially be achieved through the centrifugation in a short time span and thus it paves the way for designing and synthesizing entropic alloys with intriguing properties.展开更多
The dross generated in the hot-dip Zn–Al–Mg coating process is a valuable co-product,since it contains high quantities of recyclable alloy.A new method to recover Zn–Al–Mg alloy from the industrial Zn–Al–Mg dros...The dross generated in the hot-dip Zn–Al–Mg coating process is a valuable co-product,since it contains high quantities of recyclable alloy.A new method to recover Zn–Al–Mg alloy from the industrial Zn–Al–Mg dross was proposed using supergravity separation.The separation efficiency was analyzed as a function of gravity coefficient(G),separation time,and separation temperature.The separation of Zn–Al–Mg alloy from the dross can be achieved at G>100.The alloy content in the dross decreased gradually with an increase in the gravity coefficient,the separation time,and the separation temperature.The alloy ratio in the enriched dross decreased almost linearly as the gravity coefficient increased,and the recovery of Zn–Al–Mg alloy from the dross exceeded 78%;these results were consistent with the results of the FactSage software calculation.The purified alloy can be in-situ used in the hot-dip Zn–Al–Mg bath for production.The feasibility of supergravity separation as a promising process for efficiently recovering Zn–Al–Mg alloy from Zn–Al–Mg dross was thus demonstrated.展开更多
基金Supported partially by the National Natural Science Foundation of China under Grant Nos 90103004, 90403023, 10375087 and 10373003.
文摘Since the special relativity can be viewed as the physics in an inverse Wick rotation of four-dimensional （4D） Euclid space, which is at almost equal footing with the 4D Riemann/Lobachevski space, there should be important physics in the inverse Wick rotation of 4D Riemann/Lobachevski space. Thus, there are three kinds of special relativity in de Sitter（dS）/Minkowski/anti-de Sitter（AdS） space at almost equal footing, respectively. There is an instanton tunnelling scenario in the Riemann-de Sitter case that may explain why A be positive and link with the multiverse.
基金financially supported by the National Natural Science Foundation of China (No. 51704022)
文摘Printed circuit boards（PCBs） contain many toxic substances as well as valuable metals, e.g., lead（Pb） and tin（Sn）. In this study, a novel technology, named supergravity, was used to separate different mass ratios of Pb and Sn from Pb–Sn alloys in PCBs. In a supergravity field, the liquid metal phase can permeate from solid particles. Hence, temperatures of 200, 280, and 400°C were chosen to separate Pb and Sn from PCBs. The results depicted that gravity coefficient only affected the recovery rates of Pb and Sn, whereas it had little effect on the mass ratios of Pb and Sn in the obtained alloys. With an increase in gravity coefficient, the recovery values of Pb and Sn in each step of the separation process increased. In the single-step separation process, the mass ratios of Pb and Sn in Pb–Sn alloys were 0.55, 0.40, and 0.64 at 200, 280, and 400°C, respectively. In the two-step separation process, the mass ratios were 0.12 and 0.55 at 280 and 400°C, respectively. Further, the mass ratio was observed to be 0.76 at 400°C in the three-step separation process. This process provides an innovative approach to the recycling mechanism of Pb and Sn from PCBs.
文摘A previous preon scenario for the standard model particles, based on unbroken supersymmetry, is applied to the problem of matter-antimatter asymmetry. Attention is paid to the fact that the asymmetric hydrogen atom—like all atoms—can be described in terms of symmetric preons. Preons are created in the early universe. The matter-antimatter asymmetry is caused by stochastic correlations in charge density fluctuations of preons and antipreons and by the subsequent preon combinatorial mechanism to form quarks and leptons, and finally the three lightest elements. A tentative gravitino mass estimate is given based on minimal interference with nucleosynthesis. With local supersymmetry the scenario can be extended to supergravity.
基金supported by the National Natural Science Foundation of China(Grant No.11988102)the New Cornerstone Science Foundation through the XPLORER PRIZE.
文摘We report an experimental study of the local temperature fluctuationsδT and heat transport in a partitioned supergravitational turbulent convection system.Due to the dynamics of zonal flow in the normal system without partition walls,the probability density function(PDF)at a position in the mixing zone exhibits a downward bending shape,suggesting that the multi-plume clustering effect plays an important role.In partitioned system,zonal flow is suppressed and the PDFs indicate that the single-plume effect is dominant.Moreover,statistical analysis shows that the PDF ofδT is sensitive to supergravity.Additionally,the thermal spectra follow P(f)∼f^(-5) in the normal system,which is relevant to the zonal flow.The absolute value of the scaling exponent of P(f)and the scaling range become small in the partitioned system,which provides another evidence for the influence of zonal flow on the energy cascade.Further,heat transfer enhancement is found in the partitioned system,which may result from zonal flow being restricted and then facilitating the radial movement of thermal plumes to the opposite conducting cylinder.This work may provide insights into the flow and heat transport control of some engineering and geophysical flows.
基金supported by Beijing Natural Science Foundation(Grant No.3244041).
文摘In the current work,we investigated hydrogen/air flame propagation under supergravity conditions.Results show that when gravity is in the same/opposite direction as flame propagation,it leads to acceleration/deceleration of the flame,and that such an effect could substantially modify the flame propagation and structure at high gravity levels.Furthermore,for the absolute and relative flame propagation speeds,the gravity-affected flame speed shows opposite trends as the absolute flame speed is more affected by the local induced flow field,while the relative flame speeds are controlled by the super-adiabatic or sub-adiabatic flame temperature.The gravity-affected thermal and chemical flame structures are also examined through the influence of the mixture equivalence ratio,pressure,and flame stretch.
基金the financial support from the National Natural Science Foundation of China (NSFC, 51471025 and 51671020)
文摘Investigating the microstructures and properties of gradient materials has been regarded as a promising way to accelerate the identification of optimal compositions for applications. Herein, a supergravity method is applied to prepare the graded entropic alloys Al-Zn-Li-Mg-Cu. Through carefully optimizing the experimental conditions, the graded microstructures and hardness values appear after the supergravity technique. The morphology of the alloy significantly changes from the bulk intermetallics to eutectic structures along the supergravity force direction, which results from the crushed and graded aluminum oxide combined with the extremelystrong force. The results show that with this supergravity method, a performance-enhanced alloy can potentially be achieved through the centrifugation in a short time span and thus it paves the way for designing and synthesizing entropic alloys with intriguing properties.
基金supported by the National Natural Science Foundation of China(Grant No.52174275).
文摘The dross generated in the hot-dip Zn–Al–Mg coating process is a valuable co-product,since it contains high quantities of recyclable alloy.A new method to recover Zn–Al–Mg alloy from the industrial Zn–Al–Mg dross was proposed using supergravity separation.The separation efficiency was analyzed as a function of gravity coefficient(G),separation time,and separation temperature.The separation of Zn–Al–Mg alloy from the dross can be achieved at G>100.The alloy content in the dross decreased gradually with an increase in the gravity coefficient,the separation time,and the separation temperature.The alloy ratio in the enriched dross decreased almost linearly as the gravity coefficient increased,and the recovery of Zn–Al–Mg alloy from the dross exceeded 78%;these results were consistent with the results of the FactSage software calculation.The purified alloy can be in-situ used in the hot-dip Zn–Al–Mg bath for production.The feasibility of supergravity separation as a promising process for efficiently recovering Zn–Al–Mg alloy from Zn–Al–Mg dross was thus demonstrated.
