A statistical mechanics method is proposed for calculation of potential ofmean force (PMF). In the case of solvophobic or solvophilic macroparticles immersed in solvent bathof soft sphere or Lennard-Jones particles, p...A statistical mechanics method is proposed for calculation of potential ofmean force (PMF). In the case of solvophobic or solvophilic macroparticles immersed in solvent bathof soft sphere or Lennard-Jones particles, prediction accuracy for the PMF and MF from the simplestimplementation of the proposed method, where hypernetted chain approximation is adopted forcorrelation of the macroparticle-macroparticle at infinitely dilute limit, is comparable to that ofa recent more sophisticated approach based on mixture Ornstein—Zernike integral equation / bridgefunction from fundamental measure functional. Adaptation of the present method for general complexQuids is discussed, and method for improving the accuracy is suggested. Differences and relativemerits of the present recipe compared with that based on potential distribution theory is discussed.展开更多
We report a method to produce a uniform mixture of uranium dioxide spherical particles in a tungsten matrix. This method involves mixing 0.5 weight percent of high density polyethylene binder with 60 volume percent ur...We report a method to produce a uniform mixture of uranium dioxide spherical particles in a tungsten matrix. This method involves mixing 0.5 weight percent of high density polyethylene binder with 60 volume percent uranium dioxide spheres and 40 volume percent tungsten powders. Initially, hafnium oxide spheres were used as a surrogate for uranium dioxide spheres. The HfO2/W/PE powders were thoroughly mixed in a Turbula, then mixed on a hot plate above the drop point of the binder. These powders were then densified using spark plasma sintering. Microstructure was evaluated using scanning electron microscopy, density was measured and hardness measurements were made. Initial carbon content of the powders were measured and carbon content of the sintered materials was measured. Subsequently, W/UO2/Binder powders were mixed using the same methodology to ensure the process could be used for this system. These powders were sintered using hot isostatic pressing and microstructures evaluated. The resultant microstructures contained uniform distribution of HfO2 and UO2 particles in the tungsten matrix with very low carbon content.展开更多
The coupled Gross–Pitaevskii equations for two-species BEC have been solved analytically under the Thomas-Fermi approximation(TFA). Based on the analytical solution, two formulae are derived to relate the particle nu...The coupled Gross–Pitaevskii equations for two-species BEC have been solved analytically under the Thomas-Fermi approximation(TFA). Based on the analytical solution, two formulae are derived to relate the particle numbers N_A and N_B with the root mean square radii of the two kinds of atoms. Only the case that both kinds of atoms have nonzero distribution at the center of an isotropic trap is considered. In this case the TFA has been found to work nicely. Thus, the two formulae are applicable and are useful for the evaluation of N_A and N_B.展开更多
The validity of single-fluid model in inertial confinement fusion simulations is studied by comparing the results of the multi- and single-fluid models. The multi-fluid model includes the effects of collision and inte...The validity of single-fluid model in inertial confinement fusion simulations is studied by comparing the results of the multi- and single-fluid models. The multi-fluid model includes the effects of collision and interpenetration between fluid species. By simulating the collision of fluid species, steady-state shock propagation into the thin DT gas and expansion of hohlraum Au wall heated by lasers, the results show that the validity of single-fluid model is strongly dependent on the ratio of the characteristic length of the simulated system to the particle mean free path. When the characteristic length L is one order larger than the mean free path A, the single-fluid model＇s results are found to be in good agreement with the multi-fluid model＇s simulations, and the modeling of single-fluid remains valid. If the value of L/A is lower than 10, the interpenetration between fluid species is significant, and the single-fluid simulations show some unphysical results; while the multi-fluid model can describe well the interpenetration and mix phenomena, and give more reasonable results.展开更多
文摘A statistical mechanics method is proposed for calculation of potential ofmean force (PMF). In the case of solvophobic or solvophilic macroparticles immersed in solvent bathof soft sphere or Lennard-Jones particles, prediction accuracy for the PMF and MF from the simplestimplementation of the proposed method, where hypernetted chain approximation is adopted forcorrelation of the macroparticle-macroparticle at infinitely dilute limit, is comparable to that ofa recent more sophisticated approach based on mixture Ornstein—Zernike integral equation / bridgefunction from fundamental measure functional. Adaptation of the present method for general complexQuids is discussed, and method for improving the accuracy is suggested. Differences and relativemerits of the present recipe compared with that based on potential distribution theory is discussed.
文摘We report a method to produce a uniform mixture of uranium dioxide spherical particles in a tungsten matrix. This method involves mixing 0.5 weight percent of high density polyethylene binder with 60 volume percent uranium dioxide spheres and 40 volume percent tungsten powders. Initially, hafnium oxide spheres were used as a surrogate for uranium dioxide spheres. The HfO2/W/PE powders were thoroughly mixed in a Turbula, then mixed on a hot plate above the drop point of the binder. These powders were then densified using spark plasma sintering. Microstructure was evaluated using scanning electron microscopy, density was measured and hardness measurements were made. Initial carbon content of the powders were measured and carbon content of the sintered materials was measured. Subsequently, W/UO2/Binder powders were mixed using the same methodology to ensure the process could be used for this system. These powders were sintered using hot isostatic pressing and microstructures evaluated. The resultant microstructures contained uniform distribution of HfO2 and UO2 particles in the tungsten matrix with very low carbon content.
基金Supported by the National Natural Science Foundation of China under Grant Nos.11372122,11274393,11574404,and 11275279the Open Project Program of State Key Laboratory of Theoretical Physics,Institute of Theoretical Physics,Chinese Academy of Sciences,China+1 种基金the National Basic Research Program of China(2013CB933601)Guangdong Natural Science Foundation(2016A030313313)
文摘The coupled Gross–Pitaevskii equations for two-species BEC have been solved analytically under the Thomas-Fermi approximation(TFA). Based on the analytical solution, two formulae are derived to relate the particle numbers N_A and N_B with the root mean square radii of the two kinds of atoms. Only the case that both kinds of atoms have nonzero distribution at the center of an isotropic trap is considered. In this case the TFA has been found to work nicely. Thus, the two formulae are applicable and are useful for the evaluation of N_A and N_B.
基金Supported by the National Natural Science Foundation of China under Grant Nos.11105013,10935003,11275031,11205017,and11075023,the National Basic Research Program of China under Grant No.2013CB834110,the National High-Tech R&D Program(863 Program)under Grant No.2012AA01A303
文摘The validity of single-fluid model in inertial confinement fusion simulations is studied by comparing the results of the multi- and single-fluid models. The multi-fluid model includes the effects of collision and interpenetration between fluid species. By simulating the collision of fluid species, steady-state shock propagation into the thin DT gas and expansion of hohlraum Au wall heated by lasers, the results show that the validity of single-fluid model is strongly dependent on the ratio of the characteristic length of the simulated system to the particle mean free path. When the characteristic length L is one order larger than the mean free path A, the single-fluid model＇s results are found to be in good agreement with the multi-fluid model＇s simulations, and the modeling of single-fluid remains valid. If the value of L/A is lower than 10, the interpenetration between fluid species is significant, and the single-fluid simulations show some unphysical results; while the multi-fluid model can describe well the interpenetration and mix phenomena, and give more reasonable results.
