相分离聚合法:(Ⅰ)羧酸型共聚功能微球的合成

粒径在微米级、粒度分布窄的高分子微球具有十分广泛的应用。但是由于这样规格的微球正是在一般的悬浮聚合和乳液聚合的合成范围之外,而采用二步聚合法和种子聚合法则不是需要使用特殊的反应装置,就是合成步聚十分繁复,因此至今对于这样规格高分子微球的报道不多。     

焙烧法制备凝胶渗透色谱用硅胶

多孔硅胶是凝胶渗透色谱用的一种填料。它具有化学惰性好,可用于除碱性外各种溶剂;机械强度高,能承受高压不破碎;热稳定性好,在高温溶剂下经久耐用等优点。并且它装柱简单,可直接使用干胶装柱。不溶胀,可在柱中直接更换溶剂。使用寿命长,可反复装柱且数据重复,在色谱中对液流的阻力小。有良好的分离效率。在制备各种孔径的多孔硅胶时,一般都以小孔径的硅胶作为原料,通过适当的方法来“扩孔”使孔径扩大1—2个数量级,以得到所需要孔径范围的硅胶。扩孔方法通常采用焙烧法在炉中焙烧。它操作简单,容     

Stimulated Brillouin scattering by the interaction between different-order optical and acoustical modes in an As2Se3 photonic crystal fiber

Brillouin gain spectra(BGS)in an As2Se3 photonic crystal fiber(PCF)are investigated numerically.The profiles of the BGS are simulated by calculating the characteristics of different-order optical and acoustic waves in the PCFs with different core diameters.For the small-core PCF,there are two peaks in BGS,but there is only one peak for the large-core PCF.We also reveal that in the small-core PCF,the difference of Brillouin frequency shift between the LP01 and LP11 modes is obvious,while it is not obvious in the large-core PCF.The Brillouin threshold increases with the core diameter increasing.     

相分离聚合法:(Ⅰ)羧酸型共聚功能微球的合成

Crosslinked functional microspheres with Carboxylic group have been synthesized by the method of Phaseseparated polymerization from monomers of methacrylic acid and other vinyl-type monomers. The effects of reaction condition such as comonomer, crosslinking agent, initiator and polymerization temperature, as well as polymerization time on the morphological structure of microspheres formed have been studied. The functional polymeric microspheres with good spherical form, diameter near 5 micrometers, narrow dispersion in diameter and contained carboxylic group can be synthesized stably.