Temperature dependence of surface enhanced Raman scattering on C<Subscript>70</Subscript>

The temperature dependence of surface enhanced Raman scattering of the C70 molecule is reported. The Raman scattering of C70 molecules adsorbed on the surface of a silver mirror was measured at different temperatures. The experimental results indicate that the relative intensities of the Raman features vary with the temperature of the sample. When the temperature decreases from room temperature to 0℃, the relative intensifies of certain Raman bands decrease abruptly. If we like the strongest band 1565cm^-1 as a standard value 100, the greatest decrease approaches to 43%. However, with the further decrease in the temperature these relative intensities increase and resume the value at room temperature. And such a temperature dependence is reversible. Our results show that the adsorption state of the C70 molecules on the silver surface around 0℃ changes greatly with the temperature, resulting in a decrease in relative intensities for some main Raman features of C70 molecule. When the temperature is lower than 0℃, the adsorption state changes continually and more slowly. Synchronously, eight new Raman features, which have not ever been reported in fiterature, are observed in our experiment and this enriches the basic information of the vibrational modes for C70 molecule.     

Electrochromic effect in domain-inversion process in LiNbO3： Ru： Fe crystals

A reversible electrochromic effect accompanying domain-inversion during the electrical poling process in LiNbO3： Ru： Fe crystals at room temperature has been observed. In electrode area, both electrochromism and domain-inversion occur alternately, and electrochromism is also reversible during back-switch poling, which is experimentally verified and whose mechanism is briefly explained using a microstrncture ferroelectric model. In addition, because of the enhancing elcctrochromic effect, different from the undoped LiNbO3 crystals, the coercive filed （21.0 kV/mm or so） measured in LiNbO3： Ru： Fe is lower than its breakdown field, thus providing a possible new technique for realizing the domain-inversion by constant electric field rather than a pulsed one.     

石灰煤球机械强度成因的探讨

石灰碳化煤球是以石灰为粘结剂并经碳化处理而制得具有一定机械强度的煤球,目前广泛用于小合成氨厂。　到日前为止,人们普遍认为碳化处理是获得一定机械强度的“石灰煤球”的唯一途径,并且不论碳化时的具体条件如何,都把煤球强度的成因归之于CaCO3骨架的形成。　我们的研究则表明,在一定温、湿度条件下,由于石灰与粉煤中具有活性的含硅矿物的相互作用可以形成一种新的胶结材料──水化硅酸一钙(CaO·SiO2·nHO2)或简写为CSH　(A)。用福州氮肥厂碳化罐中经碳化处理后的“石灰碳化煤球”(熟球)及其相应的生球和原材料的X射线分析结果。X…     

无后处理钢铁常温发黑新工艺及机理

本文介绍无后处理钢铁常温发黑剂的组成，作用及工艺，综合测试了发黑膜的性能及氧化还原的动电位曲线和发黑过程的电位－时间曲线，借助电镜扫描分析了发黑膜的形貌，提出了可能的机理。     

pH值对Bi4TiO12溶胶水解特性的影响

报道了前驱体溶液的ｐＨ值对Ｂｉ－Ｔｉ溶液的水解特性的影响，并探讨了乙醇胺的催化作用机理。研究表明，乙醇胺可调节溶液的ＰＨ值，其机理及ＨＡＣ反应，并与Ｂｉ＾＋离子生成稳定的络合物。