A simplified model is proposed for an easy understanding of the coarse-grained technique and for achieving a first approximation to the behavior of gases. A mole of a gas substance, within a cubic container, is repres...A simplified model is proposed for an easy understanding of the coarse-grained technique and for achieving a first approximation to the behavior of gases. A mole of a gas substance, within a cubic container, is represented by six particles symmetrically moving. The impacts of particles on container walls, the inter-particle collisions, as well as the volume of particles and the inter-particle attractive forces, obeying a Lennard-Jones curve, are taken into account. Thanks to the symmetry, the problem is reduced to the nonlinear dynamic analysis of a SDOF oscillator, which is numerically solved by a step-by-step time integration algorithm. Five applications of proposed model, on Carbon Dioxide, are presented: 1) Ideal gas in STP conditions. 2) Real gas in STP conditions. 3) Condensation for small molar volume. 4) Critical point. 5) Iso-kinetic energy curves and iso-therms in the critical point region. Results of the proposed model are compared with test data and results of the Van der Waals model for real gases.展开更多
The magnetic circuit of a kind of permanent magnetic sucker attached to the tracks of a wall climbing robot was researched. The formula of the attractive force of sucker to a wall was derived and the relationship betw...The magnetic circuit of a kind of permanent magnetic sucker attached to the tracks of a wall climbing robot was researched. The formula of the attractive force of sucker to a wall was derived and the relationship between the force and the air gaps was analyzed. Furthermore the effect of the parameters of the magnetic sucker on the sucker’s performance was discussed. The experiments show that proper selections of the sucker’s structural parameters can provide sufficient attractive force so as to make the wall climbing robot move safely on the steel wall surface.展开更多
文摘A simplified model is proposed for an easy understanding of the coarse-grained technique and for achieving a first approximation to the behavior of gases. A mole of a gas substance, within a cubic container, is represented by six particles symmetrically moving. The impacts of particles on container walls, the inter-particle collisions, as well as the volume of particles and the inter-particle attractive forces, obeying a Lennard-Jones curve, are taken into account. Thanks to the symmetry, the problem is reduced to the nonlinear dynamic analysis of a SDOF oscillator, which is numerically solved by a step-by-step time integration algorithm. Five applications of proposed model, on Carbon Dioxide, are presented: 1) Ideal gas in STP conditions. 2) Real gas in STP conditions. 3) Condensation for small molar volume. 4) Critical point. 5) Iso-kinetic energy curves and iso-therms in the critical point region. Results of the proposed model are compared with test data and results of the Van der Waals model for real gases.
基金Doctoral Fund of the National EducationCommittee
文摘The magnetic circuit of a kind of permanent magnetic sucker attached to the tracks of a wall climbing robot was researched. The formula of the attractive force of sucker to a wall was derived and the relationship between the force and the air gaps was analyzed. Furthermore the effect of the parameters of the magnetic sucker on the sucker’s performance was discussed. The experiments show that proper selections of the sucker’s structural parameters can provide sufficient attractive force so as to make the wall climbing robot move safely on the steel wall surface.
