镁及其合金材料超薄切片制备

高分辨透射电镜(TEM)分析是材料样品研究的重要方法,材料观察和分析结果的可靠性与样品制备密切相关,样品的处理方式不当会直接影响到TEM的分析结果。镁(Mg)是一种性质活泼的金属,对其进行透射电镜薄膜制备比较困难,本文介绍一种利用超薄切片技术制备镁及其合金的超薄切片的方法。该方法不使用水槽,可避免金属Mg与水发生反应而导致性质结构发生变化。结果表明,该方法制备的超薄切片可以在TEM下观察和拍摄高分辨像,可满足研究分析需要。     

A novel multifunction material with both electrorheological performance and luminescence property

A multifunctional material with both electrorheological（ER） performance and luminescence property was synthesized by a simple coprecipitation. The tetrabutyl titanate, as well as the Tb（NO3）3·6H2O and sulphosalicylic acid（C7H6O6S·2H2O, SSA） were chosen as starting materials. The composition, ER performance and luminescence property of the material were studied. The results showed that a novel material（TiTbSSA） with both ER performance and luminescence property was obtained. The relative shear stress τr（τr=τE/τ0, τE and τ0 were the shear stresses of the suspension with and without an applied electric field） of the suspension（30 wt.%） of the material in silicone oil reached 32.7 at a shear rate of 12.5 s–1 and an electric field strength of 4 kV/mm（DC electric field）. The material containing the rare earth（RE=Tb） complex exhibited fine luminescence performance and higher ER activity. Therefore, it is a novel multifunction material which would have wide application prospect.     

碳纤维掺杂β-环糊精包合物材料的制备和电流变性能

利用无毒、易得的β-环糊精(β-CD)作为主体,对甲基苯磺酸(PTA)作为客体,碳纤维作为掺杂材料,用研磨法,制得包合物(β-CD-PPTA)和碳纤维掺杂包合物(β-CD-PTA-C)电流变(ER)材料.FT-IR及XRD分析证实了包合物的形成.不同材料的电流变性质表明,包合PTA改善了β-CD材料的电流变性能,在包合物中掺杂碳纤维可以更有效地提高材料的电流变活性.另外,β-CD-PTA-C材料在硅油中的悬浮液具有良好的抗沉淀稳定性.     

Preparation and Electrorheological Property of Y4O（OH）9（NO3）-NH4NO3 Materials

The new electrorheological (ER) material, a particle material composed of Y4O(OH)9(NO3) and NH4NO3, was obtained.They display better ER performance.The shear stress of the suspension of Y4O(OH)9(NO3)(NH4NO3)2.8 material in dimethyl silicone oil reaches 1469 Pa at an electric field strength (E) of 4.2 kV·mm-1 and the shear rate (γ) of 150 s-1.The relative shear stress, τE/τ0 (τE and τ0 are the shear stresses at E=4.2 and 0 kV·mm-1, respectively), is up to 29, which is 19 times that of pure Y2O3 material.The dielectric and conductive property of the materials play important roles in the modification of the ER effect of the particle materials.The researches on these new ER materials are very useful for obtaining a better understanding on the mechanism of the ER effect and finding an ideal ER material.     

Preparation and Electrorheological Property of NaNO3-Doped Y2O3 Material

Theelectrorheological(ER)fluidisasuspension ofpolarizablesolidparticlesdispersedinanon con ductingliquid,exhibitingdrasticandreversible changeinrheologicalpropertieswhenanexternalelec tricfieldisappliedviaorderingofthemicrostructure intoparticulatecolumns[1].Thisrapidandreversibleresponsehaspotentialapplicationinmanyelectrically controlledmechanicaldeviceswhichtransformelectri calenergyintomechanicalenergy,suchasclutches,valves,dampingdevices,andsoon[2,3].However,ERfluidhasnotbeenutilizedlarg…