An ODE-based nonmonotone method for unconstrained optimization problems

This paper proposes an ODE-based nonmonotone method for unconstrained optimization problems, which combines the idea of IMPBOT with the nonmonotone technique. The main characteristic of this method is that at each iteration, a system of linear equations is solved only once to obtain a trial step, via a modified L-BFGS two loop recursion that requires only vector inner products, thus reducing the matrix computation and storage. Then a modified nonmonotone line search is performed to generate next iterative point instead of resolving the linear system. Under some reasonable assumptions, the method is proven to be globally and superlinearly convergent. Numerical results show the efficiency of this proposed method in practical computation.     

Fabrication of high aspect ratio subwavelength gratings based on X-ray lithography and electron beam lithography

In this paper, we present two nano-fabrication technologies that provide effective approaches for low-cost, large-scale manufacturing of nano-gratings. One grating is fabricated on polymethylmethacrylate (PMMA) with the pitch of 500 nm, and height of 2000 nm, and the other is fabricated on silicon wafer with the pitch of 666 nm, and height of 200 nm. High aspect ratio PMMA nanostructures which use X-ray lithography and electron beam lithography (EBL) are reported in this paper. These gratings can be used as molds, making it possible for industrial nano-imprinting technology to significantly cut cost and shorten process time.     

共晶键合与减薄技术的压电能量采集器（英）

采用微硅 锆钛酸铅（Si-PZT）悬臂梁结构并在悬臂梁末端附加镍质量块,构成可以工作于低频环境（小于1 000 Hz）的微压电能量采集器,一种利用压电效应将环境振动能转换为电能的器件。利用金薄膜作为中间层的共晶键合技术和PZT研磨减薄技术制备了微压电悬臂梁结构,PZT减薄实验最好结果为减薄至8 m。镍质量块（2 mm2 mm0.6 mm）采用微电铸工艺制备。通过对硅片与块材PZT的共晶键合工艺与PZT减薄技术的研究,制备出总厚度约为71 m的Si-PZT悬臂梁结构,其中硅梁厚约为47 m,PZT梁厚约为24 m。制备的微压电振动能量采集器样品的测试结果表明：在谐振频率为950 Hz,1.0g加速度激励条件下,其交流输出峰值电压可达958 mV。