Effects of Radius and Orientation of Single-Walled Carbon Nanotubes on Their Nonlinear Tensile Deformation Behaviour

By capturing the atomic information and reflecting the behaviour governed by a nonlinear potential function, an analytical molecular mechanics approach is applied to establish the constitutive relation for single-walled carbon nanotubes （SWCNTs）. The nonlinear tensile deformation curves of zigzag and armchair nanotubes with different radii are predicted, and the elastic properties of these SWCNTs are obtained. A conclusion is made that the nanotube radius has little effect on the mechanical behaviour of SWCNTs subject to simple tension, while the nanotube orientation has larger influence.     

GaN基白光LED的研制与特性

本文报导了通过低压金属有机物化学气相沉积(MOCVD)的InGaN/GaN量子阱蓝光发光二极管(LED)与钇铝石榴石(YAG)荧光粉结合而得的白光发光二极管(W-LED).在室温、正向电流20mA时,W-LED轴向亮度为170mcd,显色指数(CRI)达到82,色温(CCT)为7448K,CIE色坐标是(0.296,0.316),接近纯白色(0.33,0.33).随着注入电流的增强,测量并探讨了白光LED的发射光谱与发光强度的变化.     

Young＇s Modulus Anisotropy and Magnetomechanical Damping of [110] Oriented Tb0.3Dy0.7Fe1.95 Alloy

The △E effect and the magnetoelastic or magnetomechanical damping of vibrations in [110] oriented Tbo.aDyo.TFe1.95 alloy are experimentally studied by quasi-static stress-strain measurements under various constant magnetic fields between 0 and 3000 Oe, where stress ranges are taken from about 0 to -25, -50, -75 MPa. The linear stressstrain behaviour is obtained when the magnetic field is high enough （9000 Oe）. However, the modulus E varies with the angle θ between the compressive stress and magnetic field （9000 Oe）, which shows that the anisotropy of the modulus E is related to the magnetic domain distribution.     

铁电材料的本构关系及相关问题研究进展

铁电材料以其力电耦合性能而在传感器、智能材料与结构等诸多领域获得广泛地应用．铁电材料的本构关系也因此成为研究热点．本文对铁电材料的本构关系以及与之相关的细观力学研究方法、宏观唯象研究方法、宏细观相结合的研究方法等问题的国内外研究进展作了一简要的评述．