By using the molecular dynamic simulation method with a fourth-order Runge--Kutta algorithm, a two-dimensional dc- and ac-driven Frenkel--Kontorova （FK） model with a square symmetry substrate potential for a square ...By using the molecular dynamic simulation method with a fourth-order Runge--Kutta algorithm, a two-dimensional dc- and ac-driven Frenkel--Kontorova （FK） model with a square symmetry substrate potential for a square lattice layer has been investigated in this paper. For this system, the effects of many different parameters on the average velocity and the static friction force have been studied. It is found that not only the amplitude and frequency of ac-driven force, but also the direction of the external driving force and the misfit angle between two layers have some strong influences on the static friction force. It can be concluded that the superlubricity phenomenon appears easily with a larger ac amplitude and lower ac frequency for some special direction of the external force and misfit angle.展开更多
The dry friction force between two contacting surface layers is studied.The upper layer is arrangedon a two-dimensional square lattice and driven by an external driving force.The lower layer is approximated by atwo-di...The dry friction force between two contacting surface layers is studied.The upper layer is arrangedon a two-dimensional square lattice and driven by an external driving force.The lower layer is approximated by atwo-dimensional periodic substrate potential.This model,usually called two-dimensional Frenkel-Kontorova model,isapplied to study the friction forces in this paper.The behaviors of different substrate potential strongly affect the staticfriction force.It is found that the system has strong anisotropic character.The possibility to obtain superlubricity issuggested.展开更多
我们在外部 DC 力量驾驶的非消散的 Frenkel Kontorova (FK ) 链报导性变态的震荡的繁殖，它与有相等的速度的局部性的模式的平常的繁殖不同。当纽结搬到外部 DC 力量的相反的方向时，纽结将被加速，外部力量地里的 FK 链的潜力被转变...我们在外部 DC 力量驾驶的非消散的 Frenkel Kontorova (FK ) 链报导性变态的震荡的繁殖，它与有相等的速度的局部性的模式的平常的繁殖不同。当纽结搬到外部 DC 力量的相反的方向时，纽结将被加速，外部力量地里的 FK 链的潜力被转变是纽结的动能。如果纽结到达 FK 链的边界，纽结将被弹起回来并且搬到相反的方向，那么，纽结将逐渐地被速度，纽结的动能被转变是外部力量地里的 FK 链的潜力。如果纽结的速度到达零，纽结将搬到外部 DC 力量再驾驶的相反的方向，并且一个新震荡周期开始。模拟结果确切在外部力量地里表明在纽结的动能和 FK 链的潜力之间的转变。有趣的精力交换被性变态的特殊拓扑学导致，并且另外的局部性的模式例如呼吸 ers 和信封 solitons，没有有趣的现象。展开更多
A one-dimensional （1D） Frenkel-Kontorova （FK） model is studied numerically in this paper, and two new analytical solutions （a supersonic kink and a nonlinear periodic wave） of the Sine-Gordon （SG） equation （c...A one-dimensional （1D） Frenkel-Kontorova （FK） model is studied numerically in this paper, and two new analytical solutions （a supersonic kink and a nonlinear periodic wave） of the Sine-Gordon （SG） equation （continuum limit approximation of the FK model） are obtained by using the Jacobi elliptic function expansion method. Taking these new solutions as initial conditions for the FK model, we numerically find there exist the supersonic kink and the nonlinear periodic wave in these systems and obtain a lot of interesting and significant results. Moreover, we also investigate the subsonic kink and the breather in these systems and obtain some new feature.展开更多
The transport properties in a kind of simple system are studied within the framework of a generalized Frenkel Kontorova model where the chain is composed of two kinds of atoms. Its studied mobility includes two aspect...The transport properties in a kind of simple system are studied within the framework of a generalized Frenkel Kontorova model where the chain is composed of two kinds of atoms. Its studied mobility includes two aspects: the velocity mobility B v and the momentum mobility B m . The effective system temperatures for the two subchains, T e 1 and T e 2 are defined, respectively. For the underdamped case, the regime of nonlinear response becomes wider and more "steps" occur when the value of m increases. For m = 1, T e 1(F) = T e 2(F) . For m >1, T e 1(F) > T e 2(F) and the difference increases with the increase of m . The momentum transportation shows very different behavior from that of the velocity transportation. Within a prescribed intermediate "steps" of B v(F) or B m(F) , both of them decrease with the increase of F and B m(F) decreases more quickly. For the case of overdamping and nonzero temperature, the hysteresis interval becomes thinner and the transitions become smoother. The increase of m makes the hysteresis thinner and the transitions smoother. When T is high, all the transitions are smeared out, and the diatomic effects become unimportant. We expect these results contribute to the understanding of the atomic processes occurring at the interface of two materials when they are brought together and moved with respect to one another.展开更多
The dynamics of a certain density of interacting atoms arranged on a two-dimensional square lattice, which is made to slide over a two-dimensional periodic substrate potential with also the quare lattice symmetry, in ...The dynamics of a certain density of interacting atoms arranged on a two-dimensional square lattice, which is made to slide over a two-dimensional periodic substrate potential with also the quare lattice symmetry, in the presence of dissipation, by an externally applied driving force, is studied. By rotating the misfit angle θ, the dynamical behaviour displays two different tribological regimes： one is smooth, the other becomes intermittent. We comment both on the nature of the atomic dynamics in the locked-to-sliding transition, and on the dynamical states displayed during the atom motion at different values of the driving force. In tribological applications, we also investigate how the main model parameters such as the stiffness strength and the magnitude of the adhesive force affect the static friction of the system. In particular, our simulation indicates that the superlubricity will appear.展开更多
We investigate the interactions of lattice phonons with Frenkel exciton, which has a small radius in a twodimensional discrete molecular lattice, by the virtue of the quasi-discreteness approximation and the method of...We investigate the interactions of lattice phonons with Frenkel exciton, which has a small radius in a twodimensional discrete molecular lattice, by the virtue of the quasi-discreteness approximation and the method of multiplescale, and obtain that the self-trapping can also appear in the two-dimensional discrete molecular lattice with harmonic and nonlinear potential. The excitons＇ effect on the molecular lattice does not distort it but only causes it to localize which enables it to react again through phonon coupling to trap the energy and prevent its dispersion.展开更多
基金supported by the National Natural Science Foundation of China (Grand Nos. 50575217, 10875098 and 50421502)the Natural Science Foundation of Northwest Normal University (Grant Nos. NWNU-KJCXGC-03-17 and NWNU-KJCXGC-03-48)
文摘By using the molecular dynamic simulation method with a fourth-order Runge--Kutta algorithm, a two-dimensional dc- and ac-driven Frenkel--Kontorova （FK） model with a square symmetry substrate potential for a square lattice layer has been investigated in this paper. For this system, the effects of many different parameters on the average velocity and the static friction force have been studied. It is found that not only the amplitude and frequency of ac-driven force, but also the direction of the external driving force and the misfit angle between two layers have some strong influences on the static friction force. It can be concluded that the superlubricity phenomenon appears easily with a larger ac amplitude and lower ac frequency for some special direction of the external force and misfit angle.
基金Supported by the National Natural Science Foundation of China under Grant Nos.50575217,10875098,and 50421502NWNUKJCXGC-03-17NWNU-KJCXGC-03-48
文摘The dry friction force between two contacting surface layers is studied.The upper layer is arrangedon a two-dimensional square lattice and driven by an external driving force.The lower layer is approximated by atwo-dimensional periodic substrate potential.This model,usually called two-dimensional Frenkel-Kontorova model,isapplied to study the friction forces in this paper.The behaviors of different substrate potential strongly affect the staticfriction force.It is found that the system has strong anisotropic character.The possibility to obtain superlubricity issuggested.
基金supported by Scientific Research Fund of Hunan Provincial Education Department under Grant No. 07B075Interactive Project Fund of Xiangtan University under Grant No. 061ND09Dr. Shangyou Zeng's Initial Scientific Research Fund of Xiangtan University
文摘我们在外部 DC 力量驾驶的非消散的 Frenkel Kontorova (FK ) 链报导性变态的震荡的繁殖，它与有相等的速度的局部性的模式的平常的繁殖不同。当纽结搬到外部 DC 力量的相反的方向时，纽结将被加速，外部力量地里的 FK 链的潜力被转变是纽结的动能。如果纽结到达 FK 链的边界，纽结将被弹起回来并且搬到相反的方向，那么，纽结将逐渐地被速度，纽结的动能被转变是外部力量地里的 FK 链的潜力。如果纽结的速度到达零，纽结将搬到外部 DC 力量再驾驶的相反的方向，并且一个新震荡周期开始。模拟结果确切在外部力量地里表明在纽结的动能和 FK 链的潜力之间的转变。有趣的精力交换被性变态的特殊拓扑学导致，并且另外的局部性的模式例如呼吸 ers 和信封 solitons，没有有趣的现象。
基金supported by the National Natural Science Foundation of China (Grant No 10575082)the Natural Science Foundation of Gansu Province of China (Grant No 3ZS061-A25-013)the Natural Science Foundation of Northwest Normal University of China(Grant No NWNU-KJCXGC-03-17)
文摘A one-dimensional （1D） Frenkel-Kontorova （FK） model is studied numerically in this paper, and two new analytical solutions （a supersonic kink and a nonlinear periodic wave） of the Sine-Gordon （SG） equation （continuum limit approximation of the FK model） are obtained by using the Jacobi elliptic function expansion method. Taking these new solutions as initial conditions for the FK model, we numerically find there exist the supersonic kink and the nonlinear periodic wave in these systems and obtain a lot of interesting and significant results. Moreover, we also investigate the subsonic kink and the breather in these systems and obtain some new feature.
基金NationalNatureScienceFoundationofChina (No .19775 0 0 8)
文摘The transport properties in a kind of simple system are studied within the framework of a generalized Frenkel Kontorova model where the chain is composed of two kinds of atoms. Its studied mobility includes two aspects: the velocity mobility B v and the momentum mobility B m . The effective system temperatures for the two subchains, T e 1 and T e 2 are defined, respectively. For the underdamped case, the regime of nonlinear response becomes wider and more "steps" occur when the value of m increases. For m = 1, T e 1(F) = T e 2(F) . For m >1, T e 1(F) > T e 2(F) and the difference increases with the increase of m . The momentum transportation shows very different behavior from that of the velocity transportation. Within a prescribed intermediate "steps" of B v(F) or B m(F) , both of them decrease with the increase of F and B m(F) decreases more quickly. For the case of overdamping and nonzero temperature, the hysteresis interval becomes thinner and the transitions become smoother. The increase of m makes the hysteresis thinner and the transitions smoother. When T is high, all the transitions are smeared out, and the diatomic effects become unimportant. We expect these results contribute to the understanding of the atomic processes occurring at the interface of two materials when they are brought together and moved with respect to one another.
基金Project supported by the National Natural Science Foundation of China(Grant No.10875098)the Natural Science Foundation of Northwest Normal University,China(Grant Nos.NWNU-KJCXGC-03-48and NWNU-KJCXGC-03-17)the Domestic Visiting Scholars Program of the Doctoral Candidates of Northwest Normal University,China
文摘The dynamics of a certain density of interacting atoms arranged on a two-dimensional square lattice, which is made to slide over a two-dimensional periodic substrate potential with also the quare lattice symmetry, in the presence of dissipation, by an externally applied driving force, is studied. By rotating the misfit angle θ, the dynamical behaviour displays two different tribological regimes： one is smooth, the other becomes intermittent. We comment both on the nature of the atomic dynamics in the locked-to-sliding transition, and on the dynamical states displayed during the atom motion at different values of the driving force. In tribological applications, we also investigate how the main model parameters such as the stiffness strength and the magnitude of the adhesive force affect the static friction of the system. In particular, our simulation indicates that the superlubricity will appear.
基金supported by the National Natural Science Foundation of China (Grant No 1057400)the Natural Science Foundation of Heilongjiang Province of China (Grant No A200506)
文摘We investigate the interactions of lattice phonons with Frenkel exciton, which has a small radius in a twodimensional discrete molecular lattice, by the virtue of the quasi-discreteness approximation and the method of multiplescale, and obtain that the self-trapping can also appear in the two-dimensional discrete molecular lattice with harmonic and nonlinear potential. The excitons＇ effect on the molecular lattice does not distort it but only causes it to localize which enables it to react again through phonon coupling to trap the energy and prevent its dispersion.
