纳米技术在玻璃材料中的应用

纳米粒子具有诸多奇特的理化性能。可以利用这些性质,合成出具有奇特功能的新材料。纳米技术的诞生与发展,为材料科学领域开创了一个新时代,也为玻璃材料的创新奠定了基础。无机玻璃具有透明、耐热等优点。在其中分散有纳米粒子的话,会表现出特异的热、电、光等性能。例如,将金、银、铜、硫硒化镉等纳米粒子分散到玻璃基体中,会显著加快玻璃的光学响应时间,加大三阶非线性极化率。分散的方法有:熔融法,即熔融成型后,在稍高于玻璃转变温度下热处理,令其析出纳米粒子;溶胶-凝胶法,即把纳米粒子预先混入溶胶-凝胶的先驱体溶液中,或先做出凝胶玻…     

模块化高效"双直"式蓄冰空调系统

模块化高效"双直"式ZTB系列蓄冰空调机组,集常规制冷、制冰蓄冷、融冰释冷等功能为一体.其制冷设备、蓄冷装置、辅助设备和控制调节设备4部分,组装为一个整体,实现工厂化生产.     

Effects of high-order nonlinearity and rotation on the fission of internal solitary waves in the South China Sea

A variable coefficient, rotation-modified extended Kortweg-deVries (vReKdV) model is applied to the study of the South China Sea (SCS), with focus on the effects of the high-order (cubic) nonlinearity and the rotation on the disintegration process of large-amplitude (170 m) Internal Solitary Waves (ISWs) and the semi-diurnal internal tide propagating from the deep basin station to the slope and shelf regions in a continuously stratified system. The numerical solutions show that the high-order nonlinearity significantly affects the wave profile by increasing the wave amplitude and the phase speed in the simulated area. It is shown that the initial KdV-type ISW will decay faster when the rotation dispersion is considered, however the wave profile does not change significantly and the rotation effect is not important. The simulations of the semi-diurnal internal tide indicate that the phase of the wave profile is shifted earlier when the rotation effect is included. A solitary wave packet emerges on the shelf, and the wave speed is also greater when considering the rotation dispersion. In addition, the effects of the background currents are discussed further in this paper. It is found that the background currents generally change the magnitude and occasionally change the sign of the nonlinear coefficients in the northern SCS.