In this paper,we prove the existence of sign-changing solution for nonlinear elliptic problem:-Δu=λh(x)u+a(x)f(u),by using of linking methods,where a(x) changes sign,h(x)>0 and λ>0.

By using critical theory and linking methods,we give two sets of hypotheses which guarantee the existence of non-constant solutions.

By using the linking theorem on single space and on product space developed by Zhao et al, a new approach is provided to study the existence and multiplicity results of periodic and subharmonic solutions for nonlinear difference equations and systems.

Under some nature conditions,it is proved that the conditions of Brezis-Nirenberg theorem and the conditions of link theorem given by Du are equivalent.

When annular rotary jet injects across the main flow, its curved shape and the process of dispersing the upper corners gas accumulation of U shaped working face are analyzed.

Based on the basic theory and related research achievements of jet, the entrainment and dilution effects of rotary jet on gas with high concentration were analyzed, and its deforming and curving characteristics during crosscutting the main airflow of coal faces was discussed.

Infrared control system with learning function in ambient intelligence;

Architecture of the smart home network in ambient intelligence;

Design of Cell Phone Based House-Hold Surveillance System in Ambient Intelligence Environment;