冷冻干燥中升华过程界面的微CT观察及气固相变分析  

Micro-CT observation on sublimation interface and analysis on gas-solid phase transformation of sublimation process during freeze-drying

作　　者：肖鑫[1] 陶乐仁[1] 徐振立[1] 习德成[1] 华泽钊[1] 

机构地区：[1]上海理工大学低温生物医学技术研究所,上海200093

出　　处：《低温与超导》2007年第1期84-88,共5页Cryogenics and Superconductivity

基　　金：上海市重点学科项目(T0503);上海市教育基金会曙光计划(2003);国家自然科学基金项目(50076028)资助

摘　　要：采用微CT扫描成像、图像重构及灰度值分析技术对冷冻干燥中升华过程界面及气固相变进行实验观察与分析。采用高斯误差函数拟合,计算得到冰的平均灰度值为154。在后续灰度值比价分析中,固体物料苹果本身的灰度值高于冰的灰度值,从而可以分析冰晶的移动特性。从直接扫描图像和重构图像,均可看到升华界面的移动是一个立体的移动,由它所包裹的冻结区逐渐向物料几何中心收缩。对比冻结物料和冻干物料的灰度值曲线,可见刚开始灰度值较低的冰区,在冻干结束后变成灰度值相对较高的孔疏区。In this study, Micro -CT scanning.image reconstruction and the technique of grey value analysis were used to analyze interface and phase transformation during sublimation of freeze - drying. The mean grey value of ice is 154 using simulation of gauss error function. In the following eontrastive analysis, the grey value of material itself is higher than the ice, so the moving characteristic of ice could he analyzed, blot only from direct scanning images but from reconstruction images, we could see that the movement of sublimation interface was a three - dimensional move mode, it contracted to the centre of the material. Comparing frozen material with freeze - dried apple, the ice are- a with low grey value in the beginning became the loosen pore area with high grey value after freeze - drying.

关 键 词：冷冻干燥 升华过程 CT 相变 

分 类 号：TB383[一般工业技术—材料科学与工程]