在线生物监测技术用于典型农药突发性污染的研究

水源水突发性污染监测技术是当前的研究重点,导致突发性污染事故的末知污染物可通过暴露于污染的水生生物行为改变来实现在线生物监测.通过48 h暴露,以标准水为对照,研究了经差分滤除以后,大型蚤在一定农药浓度下的相对行为变化,进一步说明生物行为生态学变化在水体生物监测中的指示作用.研究结果表明,在不同浓度百菌清、除草醚和溴氰菊酯的作用下,大型蚤的运动行为强度会发生剧烈变化,并呈现明显的剂量-效应关系.在一定浓度的农药暴露中,暴露生物的行为强度在经历一个短暂的突增后,会随暴露时间增加而逐步减弱.因此,通过监测大型蚤运动相对行为变化,可以实现对百菌清、除草醚和溴氰菊酯农药污染事故的在线生物监测.     

Study of Pseudo Spin Valves Based on $L1_{0}$ (111)-Oriented FePt and FePtCu Fixed Layer With Tilted Magnetocrystalline Anisotropy

In this paper, we demonstrate a series of pseudo-spin-valve structures based on L1₀ (111)-oriented FePt and FePtCu with titled magnetocrystalline anisotropy. Highly ordered (111)-oriented L1₀ FePtCu with large anisotropy is achieved by optimizing the Cu content. Magnetoresistance (MR) up to 5% has been obtained by 1) optimizing the FePtCu growth using different underlayers, 2) enhancing the interface spin polarization using thin CoFe at the Cu interfaces, and 3) adjusting the Cu spacer thickness. The substantial MR realized with tilted fixed layer magnetization is an important prerequisite for the realization of tilted polarizer spin torque oscillators (STOs) or spin-transfer torque magnetoresistive random access memories (STT-MRAMs).     

Microcellular foaming of plasticized thin PC sheet I. Effects of processing conditions

Novel microcellular foams using thin plasticized PC sheet were prepared by compression molding. The measurement results showed that T _g of plasticized PC was decreased and the molecular chain mobility was increased. Decrease in T _g and increase in chains mobility were contributed to the widen of foaming temperature window. Effects of processing conditions on cell size, cell density and relative density were also investigated. The experimental results show that the temperature, tributyl citrate and foaming agent content have more effects on the structures and morphology of the plasticized PC microcellular foam. Effects of experimental conditions on cell size distribution have also been discussed.     

Densification behavior of mullite-Al2TiO5 composites by reaction sintering of natural andalusite and TiO2

In this work, mullite-Al₂TiO₅ composites were fabricated by natural andalusite with TiO₂ as an additive. The densification characteristic, phase composition and mullitization process of andalusite with TiO₂ addition was investigated by the Archimedes’ principle, dilatometry, X-ray diffraction and scanning electron microscopy (SEM-EDS) techniques. The results showed that the incorporation of TiO₂ not only enhanced the thermal stability of in-situ Al₂TiO₅ in the silica liquid yielded from the mullitization of andalusite, but also accelerated andalusite decomposition and retarded mullite formation, which facilitated the sintering and densification of mullite-Al₂TiO₅ composites.     

现代方言词语也有声近义通现象

描写四川方言常用词"刨"的音义,表示用手或工具拨拉着向自己怀抱方向拉扯、聚拢或者保护之义。和普通话、其他方言的一些词相比较,并上溯其源,认为现代方言中也有声近义通现象。     

带有法兰接触面的空心圆锥接口重要标准分析对比

研究国家标准、国际标准和德国标准,分析国际标准带有法兰接触面的空心圆锥接口的型式和尺寸,剖析A型、C型、T型带有法兰接触面的空心圆锥接口的区别;对比国际标准和德国标准,指出标准在企业生产中的作用。     

高碾压混凝土坝施工过程仿真研究

本文根据碾压混凝土坝施工特点，采用计算机系统仿真技术和排队随机仿真网络理论，建立了高碾压混凝土坝施工交通运输系统排队网络仿真模型和高碾压坝施工浇筑过程仿真模型。应用该模型可以较好地研究高碾压混凝土坝施工过程中混凝土的运输和大坝浇筑过程问题，通过算例分析，可以看出：采用这种模型进行计算机仿真，所得结果可为高碾压混凝土坝施工组织设计提供一定参考。     

电场计算的边界配点法和边界元法及其比较

本文介绍计算静电场的边界配点法和边界元法的基本原理,同时对电场的两个实例作了计算并加以比较。