Single-phase concentrated solid solution alloys(SP-CSAs),including high-entropy alloys,have received extensive attention due to their excellent irradiation resistance.In this work,displacement cascade simulations are ...Single-phase concentrated solid solution alloys(SP-CSAs),including high-entropy alloys,have received extensive attention due to their excellent irradiation resistance.In this work,displacement cascade simulations are conducted using the molecular dynamics method to study the evolution of defects in Ni-based SP-CSAs.Compared with pure Ni,the NiCr,NiCo,and NiCu alloys exhibit a larger number of Frankel pairs(FPs)in the thermal peak stage,but a smaller number of surviving FPs.However,the NiFe alloy displays the opposite phenomenon.To explain these different observations for NiFe and other alloys,the formation energy and migration energy of interstitials/vacancies are calculated.In the NiFe alloy,both the formation energy and migration energy barrier are higher.On the other hand,in NiCr and other alloys,the formation energy of interstitials/vacancies is lower,as is the migration energy barrier of interstitials.The energy analysis agrees well with previous observations.The present work provides new insights into the mechanism behind the irradiation resistance of binary Ni-based SP-CSAs.展开更多
Flow characterization of high-pressure dense-phase pneumatic conveying of coal powder is not fully understood. To further reveal the dynamic behavior of coal particles in dense-phase pneumatic conveying pipelines, a m...Flow characterization of high-pressure dense-phase pneumatic conveying of coal powder is not fully understood. To further reveal the dynamic behavior of coal particles in dense-phase pneumatic conveying pipelines, a method for the scale decomposition of particle motion based on empirical mode decompo- sition and Hurst analysis of experimental electrostatic signals is reported. This allows the multi-scale motion characteristics of single coal particles and particle clusters to be determined. Micro-, meso-, and macro-scale subsets were reconstructed, which reflected the different behaviors of the coal particles: specifically, dynamic features of the micro-scale subset represented features of single particle collisions and frictional interactions; dual ffactal characteristics of the meso-scale subset described the motion of coal particle clusters; and features of the macro-scale subset reflected persistent dynamic behavior of the entire pneumatic conveying system. Motion behavior of single particles and particle clusters could be respectively investigated by considering the relative energies of the micro- and meso-scale contributions to the electrostatic signal. This was verified both by theoretical analysis and experiment.展开更多
Rainbow refractometry is widely used to measure the radius and real part of refractive index of a cylinder. However, studies on the detection of imaginary part of the refractive index with rainbow technique were scarc...Rainbow refractometry is widely used to measure the radius and real part of refractive index of a cylinder. However, studies on the detection of imaginary part of the refractive index with rainbow technique were scarce. This paper presents a new method for simultaneously measuring the radius, real and imaginary part of the refractive index of a cylinder, on the basis of the Airy theory and the Bouguer theory. The rainbows produced by the illuminated cylinder at a capillary exit are captured by a CCD camera in a lab- scale system, and then processed by the proposed method. Experimental results showed that the radius, real and imaginary part of the refractive index can be accurately determined when the SNR (signal to noise ratio) of the ripple structure is sufficiently high. However, the SNR of the ripple structure gradually decreases with decreasing scattering intensity of the cylinder, leading to larger measurement errors of the radius and real part of the refractive index. The relative error of the imaginary part of the refractive index derived from the measurement errors of the radius and real part of the refractive index, is less than 3.4%.展开更多
The gas/solid flow regime of dense-phase pneumatic conveying of pulverized coal under a pressure of 4.0 MPa in horizontal pipeline 10 mm in diameter, is monitored by electrical capacitance tomography (ECT) using 8 e...The gas/solid flow regime of dense-phase pneumatic conveying of pulverized coal under a pressure of 4.0 MPa in horizontal pipeline 10 mm in diameter, is monitored by electrical capacitance tomography (ECT) using 8 electrodes. To improve the accuracy of the capacitance measurement, an AC-based singlechannel capacitance measuring circuit was developed, and a modified iterative Landweber algorithm was used to reconstruct the image. A two-fluid model based on the kinetic theory of granular flow was used to study the three-dimensional steady-state flow behavior of dense-phase pneumatic conveying of pulverized coal.展开更多
基金supported by the National Natural Science Foundation of China(12232008,12072211)Foundation of Key laboratory(2022JCJQLB05703)Sichuan Province Science and Technology Project(2023NSFSC0914,2020JDJQ0029).
文摘Single-phase concentrated solid solution alloys(SP-CSAs),including high-entropy alloys,have received extensive attention due to their excellent irradiation resistance.In this work,displacement cascade simulations are conducted using the molecular dynamics method to study the evolution of defects in Ni-based SP-CSAs.Compared with pure Ni,the NiCr,NiCo,and NiCu alloys exhibit a larger number of Frankel pairs(FPs)in the thermal peak stage,but a smaller number of surviving FPs.However,the NiFe alloy displays the opposite phenomenon.To explain these different observations for NiFe and other alloys,the formation energy and migration energy of interstitials/vacancies are calculated.In the NiFe alloy,both the formation energy and migration energy barrier are higher.On the other hand,in NiCr and other alloys,the formation energy of interstitials/vacancies is lower,as is the migration energy barrier of interstitials.The energy analysis agrees well with previous observations.The present work provides new insights into the mechanism behind the irradiation resistance of binary Ni-based SP-CSAs.
基金The authors wish to express their gratitude to the National Natural Science Foundation of China (Grant Nos. 51506074 and 51376049) for supporting the research reported in this paper.
文摘Flow characterization of high-pressure dense-phase pneumatic conveying of coal powder is not fully understood. To further reveal the dynamic behavior of coal particles in dense-phase pneumatic conveying pipelines, a method for the scale decomposition of particle motion based on empirical mode decompo- sition and Hurst analysis of experimental electrostatic signals is reported. This allows the multi-scale motion characteristics of single coal particles and particle clusters to be determined. Micro-, meso-, and macro-scale subsets were reconstructed, which reflected the different behaviors of the coal particles: specifically, dynamic features of the micro-scale subset represented features of single particle collisions and frictional interactions; dual ffactal characteristics of the meso-scale subset described the motion of coal particle clusters; and features of the macro-scale subset reflected persistent dynamic behavior of the entire pneumatic conveying system. Motion behavior of single particles and particle clusters could be respectively investigated by considering the relative energies of the micro- and meso-scale contributions to the electrostatic signal. This was verified both by theoretical analysis and experiment.
基金the National Natural Science Foundation of China(No.50906012)Research Award Program for Outstanding Young Teachers in Southeast University,China(No.3203001202)+2 种基金QingLan Project(No.1103000126)Scientific Research Foundation of Graduate School of Southeast University(YBJJ1220)Research and Innovation Project for College Graduates of Jiangsu Province(CLCX-0106)
文摘Rainbow refractometry is widely used to measure the radius and real part of refractive index of a cylinder. However, studies on the detection of imaginary part of the refractive index with rainbow technique were scarce. This paper presents a new method for simultaneously measuring the radius, real and imaginary part of the refractive index of a cylinder, on the basis of the Airy theory and the Bouguer theory. The rainbows produced by the illuminated cylinder at a capillary exit are captured by a CCD camera in a lab- scale system, and then processed by the proposed method. Experimental results showed that the radius, real and imaginary part of the refractive index can be accurately determined when the SNR (signal to noise ratio) of the ripple structure is sufficiently high. However, the SNR of the ripple structure gradually decreases with decreasing scattering intensity of the cylinder, leading to larger measurement errors of the radius and real part of the refractive index. The relative error of the imaginary part of the refractive index derived from the measurement errors of the radius and real part of the refractive index, is less than 3.4%.
基金supported by National Natural Science Foun-dation of China under grants 50836003, 50906012,50906013Major State Basic Research Projects (grant 2010CB227002)
文摘The gas/solid flow regime of dense-phase pneumatic conveying of pulverized coal under a pressure of 4.0 MPa in horizontal pipeline 10 mm in diameter, is monitored by electrical capacitance tomography (ECT) using 8 electrodes. To improve the accuracy of the capacitance measurement, an AC-based singlechannel capacitance measuring circuit was developed, and a modified iterative Landweber algorithm was used to reconstruct the image. A two-fluid model based on the kinetic theory of granular flow was used to study the three-dimensional steady-state flow behavior of dense-phase pneumatic conveying of pulverized coal.