高性能聚偏氟乙烯基柔性压电材料的设计策略进展

压电现象在新能源开发、 传感、 医药材料设计及可穿戴电子设备中具有广泛的潜在应用, 并受到普遍重视. 在压电材料中, 聚偏氟乙烯(PVDF)及其共聚物因具有良好的柔韧性、 易加工性、 稳定性和生物相容性等优点而备受关注. 本文综合评述了近年来在制备工艺和材料复合两个维度提高PVDF基压电材料输出性能的研究进展. 在研究PVDF压电性原理的基础上, 阐释了流延法、 静电纺丝法、 拉丝法及纳米限域策略等工艺和添加小分子、 高分子、 石墨类粒子及无机纳米粒子等复合策略提升其压电性能的机理. 这些制备工艺的提高和填料的掺杂有助于偶极子的排列和高β相的形成. 最后, 对目前存在的一些挑战进行了概述和讨论, 并对PVDF基材料的发展前景提出展望.     

中国固态增殖剂实验包层小模块工程结构设计与研制工艺探讨

为部分验证中国固态增殖剂TBM 模块中原尺寸模块结构设计的合理性和研制工艺的可行性,针对性地开展了TBM 小模块(仅高度为1/3)研制工作。在前期设计工作基础上,开展TBM 小模块结构详细优化设计与分析,提出模块加工、连接及集成装配等工艺方案,为TBM 小模块的工程化试制奠定坚实基础。     

Arrays of gold microelectrodes made from split integrated circuit chips

A simple and inexpensive way to fabricate arrays of gold microelectrodes is proposed. Integrated circuit chips are sawed through their middle, normal to the longest axis, leading to destruction of the silicon circuit and rupture of the gold wires that interconnect it with the external terminals. Polishing the resulting rough surface converts the tips of the wires embedded in the chip halves into arrays of gold microdisks of about 25 μm diameter. The number of active microelectrodes (MEs), of an array depends on the number of pins in the chip, n, being typically (n/2)-4. These MEs can be used individually or externally interconnected in any combination. X-ray images of the chips and micrographs of the resulting surface of the polished arrays have revealed variable distances between neighbor MEs, which are however, larger than 10 times the radius of the disks. This feature of the MEs prevents diffusional cross-talk between electrodes. The use of these microdisk electrodes for analytical purposes exhibits sigmoidal voltammograms, and chronoamperometric experiments confirm the nonlinear i vs. t^1/2 plots, typical for processes where radial diffusion prevails, Satisfactory uniformity was observed for the response of each electrode of an array, indicating similarity of geometry and disk areas. The potentialities of these MEs were demonstrated by the determination of cadmium at ppb levels using square wave voltammetry with preconcentration. Due to the relative ease with which these MEs can be manufactured and their good performance in (chemical) analysis, wide applications in electrochemistry and electroanalysis is envisioned.     

Fabrication and Adsorption Properties of Hybrid Material with Micropores from SBA-15

A novel hybrid material with microporous structure was fabricated from SBA-15 with mesopores via silane modification and hydrolysis. Two kinds of pores with diameters of 6.5 and 1.9 nm were found in the hybrid material. Compared to that of SBA-15, the surface area of the hybrid material increased from 395.9 m²/g to 667.4 m²/g while its porous volume decreased. The new hybrid material was found to have high efficiency in removing NaCl from solution, and the maximum adsorption capacity of it was ca. 517.5 mg/g.     

红绿共振互补光变亚波长微结构制作与分析

剖析了双层亚波长光栅微结构的设计及制作原理,提出了一种亚波长微结构设计与制作的新方法,其特点是以矩形亚波长光栅设计微结构,用全息干涉光刻及涂布的方法制作,却不影响设计微结构的共振及光变特性,还能改善反射光的颜色质量。用该方法设计及制作了具有“红绿”共振互补光变效果的亚波长防伪微结构,检验了其共振光变光谱与颜色变化特征。研究表明：制作的全息光栅微结构的共振及光变特征如共振光谱、颜色、光谱峰及峰分裂等与预先设计的相同;矩形亚波长光栅并不是共振的必要条件,其他面形光栅微结构的衍射特性和等效波导若与矩形光栅微结构的相同,则其相关特性相同;用新方法设计及制作亚波长光变微结构的工艺是可行的,既降低了设计微结构的加工难度,又便于用现有的全息生产设备批量生产。     

Analysis of integrated corner mirrors by using a wide-angle beam propagation method

An integrated corner mirror is analyzed by using a two-dimensional (2D) wide-angle beam propagation method (WA-BPM) combining with an effective index method (EIM). Both the reflection efficiency and the phase variation due to a total internal reflection (TIR) for the TE and TM modes are calculated. A non-perfect fabrication (such as a tilted or displaced mirror) introduces an additional reflection loss and some errors of the phase variation. The additional reflection loss due to a tilted mirror increases rapidly as the tilted angle increases and becomes more sensitive to the tilted angle when the confinement of the waveguide becomes weaker. It is shown that the displacement of a mirror influences the phase variation greatly and the difference of the phase variation between the TE and TM modes is not sensitive to the displacement of the mirror.     

Analysis for fabrication errors of arrayed waveguide grating multiplexers

Based on the transmission theory, parameter optimization is performed, and effects of fabrication errors on transmission characteristics are analyzed for a 33×33 polymer arrayed waveguide grating (AWG) multiplexer around the central wavelength of 1550.918 nm with the wavelength spacing of 0.8 nm. Simulated results show that fabrication errors result in the shift of the transmission spectrum, and lead to the increase of the crosstalk compared with the device theoretically designed. Furthermore, accumulation and compensation of fabrication errors are investigated. In order to realize the normal demultiplexing of the fabricated AWG device, the allowed fabrication errors are discussed.     

Nb/A1-AlO_X/Nb隧道结的制备研究

通过改进RIE的刻蚀工艺和绝缘层的生长工艺,在SiO2/Si衬底上制备出了性能良好的超导Nb/A1-AlOX/Nb隧道结。采用CF4作为刻蚀气体,降低了RIE对结势垒层和衬底SiO2层的刻蚀。使用PECVD生长绝缘层SiO2,改善了绝缘性能,从而降低了隧道结的漏电流。     

阵列波导光栅的简便模拟方法及应用

结合等效折射率方法并利用高斯光束近似给出了一种简便的模拟计算阵列波导光栅方法,可实现AWG锔模拟模拟计算结果与理论公式计算结果吻合利用这种模拟方法,模拟了一个阵列波导光栅(AWG)实例,并考察了阵列波导条数对器件性能的影响,最后分析了制造工艺误差对器件性能的影响     

圆锥磁绝缘传输线的横向空间电荷流

根据电磁场基本理论及电子运动守恒方程，导出圆锥传输线横向空间电荷流的数值模型和磁绝缘临界条件。通过数值计算，讨论了电压及圆锥几何结构参数等对横向空间电荷流和磁绝缘性能的影响。电压较高时,无磁场的空间电荷流较大，而磁绝缘性能更好。在传输线的三个几何参数中，几何因子对传输性能影响最大。