A Simple Method for Generating Discrete Multi-Component Integrable Hierarchy

For M×N spectral matrix, a kind of operation ？ which satisfies combination law （a？b）？c=a？（b？c） is introduced. The discrete multi？component zero-curvature equation is deduced by using the new operation ？, and a simple method for constructing discrete multi-component integrable hierarchy is proposed. As its application, the multi-component Toda hierarchy and its two kinds of integrable couplings are worked out.     

耐上千摄氏度高温的光子晶体问世

据美国物理学家组织网近日报道，美国麻省理工学院（MIT）的一个研究小组找到了一种采用金属钨或钽制造可耐受1200℃高温的光子晶体途径。这种材料可广泛应用于智能手机、红外化学探测器和传感器、深度探索太空的宇宙飞船等供电装置。相关论文刊登在最新一期的美国《国家科学院院刊》上。