外激励下压电球壳的球对称稳态响应分析

对压电球壳空间球对称稳态响应问题进行了研究。考虑空间球对称压电材料,不计体力和自由电荷,在球坐标下利用弹性理论,由压电材料的本构方程、几何方程和运动方程导出了外激励作用下位移、应力、应变、电势、电位移和电场强度各量的稳态解,并对带压电激励和感应层的弹性球壳的球对称响应问题进行了求解。该结果可以给结构的空间球对称动力控制问题提供良好的理论依据,为日后对于一般性的空间动力问题的研究提供参考。     

考虑激励确定作动器优化布置方法的研究

作动器优化布置是振动主动控制中的一个重要问题。本文考虑了外部激励的作用,提出了一种与独立模态空间控制方法结合使用的作动器位置优化准则。为使系统具有最大可控度,依据被控结构动态响应中各阶模态贡献的大小,建立相应的目标函数通过求其极大值,可得出作动器优化布置方案。最后通过一个算例验证了所提出理论与方法的有效性,从算例中可以看出,作动器的优化位置与激振力的位置和频率有直接联系。     

ICP-AES法测定青壳鸡蛋中的13种元素

用高压消化罐消解后,ＩＣＰ－ＡＥＳ法同时测定青壳鸡蛋中Ｃａ、Ｍｇ、Ｆｅ、Ｍｎ、Ｚｎ、Ｃｕ、Ｐ、Ｉ、Ｓｅ、Ｓｂ、Ｂａ、Ｃｒ、Ｃｄ等１３种元素的含量,在优化实验条件下,ＲＳＤ为１．２４％－８．７６％,加标回收率为９３．０％－１０５．９。方法简便、可靠,结果令人满意。     

振动工程中智能结构的研究进展

介绍了智能结构的概念,评述了近年来用于振动工程中的智能结构所研究的几个基本问题：传感器,作动器,智能结构动力学建模及其振动控制,传感／作动器在结构中的优化配置,并提出了建议研究的几个问题：作动／传感材料的研究、集成技术的研究、控制器的研究和结构控制一体化优化技术     

SMA扭力驱动器的响应速度分析及实验研究

介绍了马氏体逆相变的驱动力的形成原因以及和相变阻力的关系。研究了通电加热时形状记忆合金(SMA)丝的热平衡方程以及相变时间与丝直径的关系,并进行了实验验证。将SMA丝按与筒母线方向成某夹角缠绕并粘贴在外表面可以构成SMA扭力驱动器。利用SMA丝的本构关系和圆筒的扭转应力-应变关系给出了空载情况下最大驱动扭转角对应的缠绕方向;研究了模拟飞机尾气通过扭力管进行加热时的响应速度,并与实验结果进行了比较。     

Adjustable low dynamic pumps based on hydrogels

This paper discusses the suitability of hydrogel actuators as drives of automatic pumps for long-term drug release. We demonstrate that such actuators can execute a defined task if several functional units are connected serially. Investigated functions of this pump are the adjustability of the time-delay from the initial operation up to the beginning of the drug release, opening the sterile drug ampoule, and the drug release at a specified timeframe. The described parameters to influence the pump behaviour are satisfying only for realization of continuous working devices. An outlook of the development of programmable pulsate pumps is given.     

Micro‐Raman spectroscopy and SEM/EDX applied to improve the zircon fission track method used for dating geological formations

The zircon mineral is widely studied in geochronology. In the case of the fission track method (FTM), the age is determined by the density of fission tracks at the zircon surface, which can be observed with an optical microscope after an appropriate chemical treatment (etching). The etching must be isotropic at the zircon grain surface to be used in the FTM, which leads those zircon grains whose etching is anisotropic to be discarded. The only reason for this discarding is the nonuniform morphology of the surface grain seen by optical microscopy, that is, no further physicochemical analysis is performed. In this work, combining micro‐Raman and scanning electron microscopy (SEM) to study the etching anisotropy, it was shown that zircon grains that present at least one area at the surface where the density of fission track is uniform can be used in the FTM. The micro‐Raman showed characteristic spectra of the standard zircon sample either from the areas where there are tracks or from where there are not. The only difference found was in the Raman bandwidths, which were broader for the areas with higher density of fission tracks. This suggests simply a decrease in the relative percentage of the crystalline/amorphous phases at these areas. The SEM/energy dispersive spectrometry (EDX) showed that there were no significant differences in the principal chemical composition at the areas with and without fission tracks. Copyright © 2008 John Wiley & Sons, Ltd.