High-power pulse trains excited by modulated continuous waves

Pulse trains growing from modulated continuous waves (CWs) are considered, using solutions of the Hirota equation for solitons on a finite background. The results demonstrate that pulses extracted from the maximally compressed trains can propagate preserving their shape and forming robust arrays. The dynamics of double high-power pulse trains produced by modulated CWs in a model of optical fibers, including the Raman effect and other higher-order terms, is considered in detail too. It is demonstrated that the double trains propagate in a robust form, with frequencies shifted by the Raman effect.Comment: 7 pages, 7 figure

Practice and Thinking: How to Enhance the Sense of Gain of College Students’ Ideological and Political Theory Courses

As a new and young member for national development, college students require high ideological consciousness, firm political position and profound theoretical understanding. To enhance the sense of gain from college students’ ideological and political theory courses is a hot topic of concern for Chinese ideological and political scholars in recent years, and it is also an important teaching goal for ideological and political teachers in colleges. On the basis of analyzing the connotation and influencing factors of college students’ sense of gain in ideological and political theory courses, and in grasping the combination of domestic peer research experience and actual teaching situation, we will continue to explore teaching designs and strategies to enhance the sense of gain by understanding students’ previous learning experience and development needs, adjusting the teaching strategy according to students’ listening situation, introducing visualization technology, and incorporating blended teaching practice

Anomalous pressure behavior of tangential modes in single-wall carbon nanotubes

Using the molecular dynamics simulations and the force constant model we have studied the Raman-active tangential modes (TMs) of a (10, 0) single-wall carbon nanotube (SWNT) under hydrostatic pressure. With increasing pressure, the atomic motions in the three TMs present obvious diversities. The pressure derivative of E1g, A1g, and E2g mode frequency shows an increased value (), a constant value (), and a negative value () above 5.3 GPa, respectively. The intrinsic characteristics of TMs consumedly help to understand the essence of the experimental T band of CNT. The anomalous pressure behavior of the TMs frequencies may be originated from the tube symmetry alteration from D10h to D2h then to C2h.Comment: 15 pages, 3 pages, submitted to Phys. Rev.