一种在线测量微机械薄膜残余应力的新结构

提出了一种利用临界屈曲法在线测量微机械薄膜残余应力的新结构，并采用表面微加工技术制作了两种测试样品.搭建了在线观测实验装置来实时监控释放过程中结构出现的临界屈曲变形模态，由此判断出结构内部的应力状态，同时在测得临界刻蚀深度的情况下，采用有限元方法计算出残余应力大小.借助有限元方法，先研究了多个参数对临界屈曲应力的影响，然后利用这种新结构对薄膜残余应力进行了实际测量，所得结果与微旋转结构的应力测量结果基本吻合.分析及实验表明，新结构在测量薄膜残余应力方面有许多优点，具有较高的实用价值，不仅能满足大量程的应力检测要求，而且只用一个结构就可以同时测量压应力和拉应力，从而极大提高了器件版图空间的利用率.     

Mode correlation and coherent-mode decomposition of laser beams

Theory of the coherent-mode decomposition of laser beams is proposed. The new model for the flat-topped beams proposed by Li recently is taken as an example. The analytical expressions for the M^2-factor and mode coherence coefficients of flat-topped beams have been derived in the rectangular coordinate system, by means of which the mode correlation, mode structure, and coherent-mode decomposition of flat-topped beams can be analysed.     

用半波带法求爱里斑角半径

本文根据菲涅尔半波带的几何分析方法,简便地导得了圆孔夫琅禾费衍射的中央明斑,即爱里斑角半径公式。     

LIGO计划用大尺寸蓝宝石晶体光学均匀性和弱吸收获得进展

报道了113mm× 70mm蓝宝石晶体块的光学加工精度、光学均匀性和弱吸收等方面研究所取得的最新进展。晶体整个表面加工精度达到 3个光圈 (峰谷值约为 1 6 6 6λ) ;晶体的透过波前畸变为 1个光圈 (峰谷值约为0 5 84λ) ;在紫外波段的透过大于 80 % ,可见及红外光区的透过大于 86 % ;晶体的弱光吸收系数为 35× 10 - 6 cm～ 6 5× 10 - 6 cm。     

大口径光学元件检测中的主要误差及其影响

 使用PSD作为大口径光学元件的质量评价标准,标定了测试系统的传递函数,并讨论了在对ICF驱动器中所使用的光学元件进行检测时产生的几种主要误差,分析了这些误差在进行计算和分析时可能造成的影响以及消除的方法。     

Bonding Interface Imaging and Shear Strength Prediction by Ultrasound

The propagation of a longitudinal ultrasonic wave normally incident upon an adhesively bonded structure is studied. The structure consists of adherend and adhesive layers with finite thickness. Interfaces between adherend and adhesive are regarded as distributed springs. Theoretical and experimental results show that resonant frequencies of the bonded structure vary sensitively with the interface stiffness constants and adhesive thickness, and these interface characteristics are inversed by the simulation annealing (SA) method. Furthermore, the distribution image of interface stiffnesses is compared with the state of fracture interface, and quantitative prediction of shear strength is achieved based on the distribution of interface stiffnesses and adhesive thicknesses by using a back-propagation neutral network. The average relative error of the shear strength from prediction to real value is 10.7%.     

New finite-gap solutions for the coupled Burgers equations engendered by the Neumann systems

On the tangent bundle TS^N-1 of the unit sphere S^N-1, this paper reduces the coupled Burgers equations to two Neumann systems by using the nonlinearization of the Lax pair, whose Liouville integrability is displayed in the scheme of the r-matrix technique. Based on the Lax matrix of the Neumann systems, the Abel--Jacobi coordinates are appropriately chosen to straighten out the restricted Neumann flows on the complex torus, from which the new finite-gap solutions expressed by Riemann theta functions for the coupled Burgers equations are given in view of the Jacobi inversion.     

Instability,intermixing and electronic structure at the epitaxial LaAlO3/SrTiO3(001) heterojunction

The question of stability against diffusional mixing at the prototypical LaAlO₃/SrTiO₃(001) interface is explored using a multi-faceted experimental and theoretical approach. We combine analytical methods with a range of sensitivities to elemental concentrations and spatial separations to investigate interfaces grown using on-axis pulsed laser deposition. We also employ computational modeling based on the density function theory as well as classical force fields to explore the energetic stability of a wide variety of intermixed atomic configurations relative to the idealized, atomically abrupt model. Statistical analysis of the calculated energies for the various configurations is used to elucidate the relative thermodynamic stability of intermixed and abrupt configurations. We find that on both experimental and theoretical fronts, the tendency toward intermixing is very strong. We have also measured and calculated key electronic properties such as potential energy gradients and valence band discontinuity at the interface. We find no measurable electric field in either the LaAlO₃ or SrTiO₃, and that the valence band offset is near zero, partitioning the band discontinuity almost entirely to the conduction band edge. Significantly, we find it is not possible to account for these electronic properties theoretically without including extensive intermixing in our physical model of the interface. The atomic configurations which give the greatest electrostatic stability are those that eliminate the interface dipole by intermixing, calling into question the conventional explanation for conductivity at this interface—electronic reconstruction. Rather, evidence is presented for La indiffusion and doping of the SrTiO₃ below the interface as being the cause of the observed conductivity.     

纳米晶复合永磁材料的交换耦合相互作用和磁性能

本介绍了纳米磁性材料晶粒交换耦合相互作用的有关理论。采用不同模型讨论了晶粒交换耦合相互作用对纳米单相软磁材料、永磁材料及双相复合永磁材料磁性能的影响。简述了用δM（H）曲线和不可逆磁导率的变化研究晶粒交换耦合相互作用及反磁化过程的方法。讨论了合金分配比、添加元素、制备及热处理工艺对磁体硬磁性能的影响。从理论和实验两方面分析、研究了纳米复合永磁材料的反磁化过程和矫顽力机制。     

Chaotic dynamics of active optical fiber ring resonator with optical injection

We experimentally obtain the route from period doubling to chaos in an active optical fiber ring resonator （AOFRR） with optical injection. The results show that the AOFRR is sensitive to external optical injection and demonstrate various dynamic characteristics. Meanwhile, the change of the injection strength can cause the output of the AOFRR to become periodic or chaotic. It can be confirmed that all the dynamic characteristics of the system are due to the interaction of the semiconductor laser with the erbium-doped fiber amplifier （EDFA）.