TAI对鱼明胶介质中AgBr/I超细颗粒的保护作用

TAI(4 羟基6 甲基1, 3, 3a, 7 四氮茚)可以显著影响鱼明胶介质中AgBr/I超细颗粒的生长.红外光谱测量显示,其特征NH伸缩振动带消失,表明通过形成N Ag络合物, TAI吸附到AgBr/I超细颗粒表面上.紫外吸收光谱数据分析指出, TAI分子在AgBr/I超细颗粒上吸附状态与乳剂颗粒成熟过程有关,单位表面积最大吸附量及最高覆盖率均出现在物理成熟初期的5min时,可以认为,此时TAI与Ag之间形成了最适合于吸附的空间网状结构,延长物理成熟时间, TAI在AgBr/I超细颗粒上的吸附逐渐趋于平衡状态,其单位面积吸附量及覆盖率基本不变,分别在1. 3μmol/m2 和47% ~49%水平.TEM观察此时AgBr/I超细颗粒的平均粒径与粒径分布也基本不再变化,最大平均粒径也出现在物理成熟5min时.TAI存在下,乳剂颗粒的平均粒径及其生长速率均明显低于不含TAI的乳剂颗粒,表明TAI对在鱼明胶介质中生长的AgBr/I超细颗粒具有明显的保护作用.     

Molecular mass estimation of derivatized compounds: a PFG NMR study

Pulsed-field gradient (PFG) 1H and 31P NMR methods were developed to quantitatively estimate the molecular mass of compounds, derivatized with either trichloroacetyl isocyanate (TAI) or 2-chloro-4,4,5,5-tetramethyl-1,3,2-dioxaphospholane (chlorophospholane). These agents provide selective analysis with high sensitivity for molecules containing alcohol, amine, carboxylic acid, or thiol functional groups. Tetramethylsilane (TMS) or bisphenol A was used as internal diffusion reference. The empirical relationship between relative diffusivity and molecular mass was established for a set of mono- and difunctional compounds with molecular masses in the range 32-330 g/mol. The utility of the method was demonstrated by analyzing alcohol, phenol, and carboxylic acid components in lubricating oil.