基于Si基沉积拉曼增强活性Au膜的制备与表征

研究了一种新的表面增强拉曼活性Au基底的制备方法,采用无电镀沉积方法,通过HF和HAuCl4的混合溶液对Si片进行处理获得具有不同形貌的Si基Au膜,利用扫描电子显微镜(SEM)分析了基底的表面形态和结构,测定结晶紫分子在基底表面的拉曼光谱。结果表明,Si基Au膜表面的表面增强拉曼散射(SERS)增强随制备时间的增加呈现先增强后减弱的趋势,增强效果优于常用的Au胶体系,是一种非常高效的拉曼活性增强基底。     

锶铁氧体胶态振动注模成形技术研究

通过絮凝、振动脱水工艺处理,获得固相体积分数达50%的锶铁氧体浆料,实现了高质量锶铁氧体坯体的胶态振动注模成形.分析了工艺条件对成形过程及样品质量的影响.实验表明:胶态注模成形比凝胶注模成形需要加入更多的单体与交联剂才能得到坯体强度相当的坯体;烧成后的锶铁氧体的剩余磁感应强度为420 mT,矫顽力H_(cb)为270 kA/m,最大磁能积(BH)_(max)为34 kJ/m~3.     

Effect of Ionic Strength on Boehmite Hydrogel Formation

Neutral salts were added to boehmite (γ-AlOOH) sols, and the solution and solution and interfacial chemistries were investigated during hydrogel formation. In general, gel volume increases with higher salt concentrations. Gels form in the presence of salts with monovalent anions when a critical ionic strength is reached, the value of which increases with increasing size of the anion. At the same time, the effect of interparticle distance appears more important with larger anions. The action of divalent anions is more complicated and may involve specific adsorption and complexing with the dissolved aluminum species. The concept of a critical gelation concentration is introduced analogous to the critical coagulation concentration for the flocculation of colloidal particles. The results are interpreted in terms of available models for particle-particle interactions.     

Preparation of Eu: YVO4 red and Ce, Tb: LaPO4 green phosphors by hydrolyzed colloid reaction (HCR) technique

Eu³⁺: YVO₄ red and Ce³⁺, Tb³⁺: LaPO₄ green phosphors were prepared by newly discovered hydrolized colloid reaction (HCR) technique at low temperature (< 100 °C) and atmospheric pressure utilizing subsequent calcining and reductive treatments, respectively. The incorporation of activators (Eu³⁺ and Ce³⁺, Tb³⁺) in these very porous powders was checked by X-ray diffraction (XRD), scanning electron microscopy (SEM) and luminescence investigations.     

An All Low‐Temperature Fabrication of Macroporous,Electrochemically Addressable Anatase Thin Films

Macroporous TiO₂ (anatase) thin films are fabricated by an all low‐temperature process in which substrates are dip‐coated in suspensions of mixed anatase nanoparticles and polystyrene beads, and the templating agents are removed by ultraviolet (UV) irradiation at a temperature below 50 °C. Scanning electron microscopy (SEM) and Raman spectroscopy show that the templating polymer beads are removed by UV irradiation combined with the photocatalytic activity of TiO₂. X‐Ray diffraction reveals that nanoparticle growth is negligible in UV irradiated films, while nanoparticle size increases by almost 10 times in calcined films that are prepared for comparison. The macroporous films are prepared on FTO‐(fluorine‐doped tin oxide) coated glass and ITO (indium tin oxide) coated flexible plastics and thereby used as working electrodes. In both cases, the films are electrochemically addressable, and cyclic voltammetry is consistent with the response of bulk TiO₂ for calcined films and of nanoscale‐TiO₂ for UV‐irradiated films.     

不同种类胶体在含水介质中沉积和释放特征

在进行粘土、高岭土和蒙脱石三种胶体在含水介质中沉积和释放试验的基础上,重点研究不同种类胶体在含水介质中迁移、沉积和释放的差异性,同时探讨了胶体的迁移-沉积机理。结果表明,相对于粘土胶体和蒙脱石胶体,高岭土胶体最不容易在含水介质中迁移。胶体开始释放浓度随孔隙体积数的增大迅速降低,随后变化缓慢,最后趋于稳定。粘土、蒙脱石和...     

形变悬浮胶体聚合物的实验研究

形变悬浮胶体聚合物是一种高弹性胶体颗粒,具有溶涨速度快、吸水性强、分散均匀、溶液无色透明的特点.在较低的浓度条件下形成的胶体溶液无游离水,颗粒体积分数大,具有形变压差小、形变能力强的优点.研究表明:形变悬浮胶体聚合物溶液稳定性好、抗剪切性能强.通过在多孔介质中的堆积、形变和运移,能够有效降低高渗透层渗透率,不会对低渗透层造成堵塞,可同时解决层内和层间的矛盾.在聚驱中及聚驱后应用可进一步提高原油采收率.     

Superlong-range interactions of colloids

Colloid particles have superlong-range attractive and repulsive forces. The distance between the secondary minimum of the potential energy of the interaction and the surface of the colloid is of the order of several μm and several tens of μm. These interactions clearly appear in the distribution of order-solution phase coexistence, in gathering particles to the ordered phase and in spontaneous pair formation. A new ‘Dynamic electrical multipole model and resonance effect’ is given. From this model, it is predicted that pairs will form in a shear field even in highly concentrated salt solution. Pair formation was observed after 24 hours as predicted.     

SBS改性乳化沥青生产新技术

简述改性乳化沥青的生产方法并介绍了一种生产SBS改性乳化沥青的新技术。