摘要
为了定量地研究兔胸主动脉在冻结相变温区的膨胀情况 ,本研究采用热机械分析仪 (TMA)分别研究了低温保护剂 (CPA)和冻结速率对兔胸主动脉冻结相变过程中膨胀的影响 ,研究结果表明 :( 1) 10℃ /min降温速率所对应的最大膨胀量约是 3℃ /min的 4倍 ,5℃ /min的 1.4倍 ,而且 ,降温速率越大 ,相应的热膨胀系数也越大 ;( 2 )含 5 %DMSO血管所对应的最大应变值比较接近不含DMSO时的最大应变值 ,但含有 15 %DMSO的血管在冻结相变过程中的最大线性应变只有 0 %的 1/ 2左右 ,并且 ,保护剂浓度越大 ,血管冻结相变热膨胀系数也就越小 ;( 3)在研究生物材料冻结膨胀应力时 ,不能简单地将生物材料的冻结膨胀量按照生物材料水分含量的冻结膨胀量来计算 ,而是要充分考虑降温速率。
In order to study the thermal expansion of rabbit atrery during phase change processes quantitatively, experiments were conducted wih thermal mechanical analysis (TMA) to investigate the effects of concentrations of cryoprotective agents (CPA) and cooling rates on the thermal expansion of rabbit artery during phase change processes. Results show that; (1) The maximum of thermal strain at the cooling rate of 10°C/min is approximately 4 times of that of 3°C/min, and 1.4 times than that of 5°C/min, and the higher the cooling rates, the lager the corresponing thermal expansinon coefficient (TEC); (2) The maximal thermal strain of aorta containing 5% (v/v) DMSO approaches that when DMSO is absent, however, the difference is significant when the concentration of DMSO in aorta is 15% (v/v) maximum of thermal expansion is only 1/2 of that when DMSO is absent. And the thermal expansion coefficient decreases with the concentration of DMSO increased; (3) when researching on the freezing stress of biomaterials, the quantity of thermal expansion in the whole biomaterials should not be simly calculated from that of the water in the biomaterials, instead some factors such as cooling rates, chenmical content of the tissue should be considered.
出处
《中国生物医学工程学报》
EI
CAS
CSCD
北大核心
2004年第5期455-460,432,共7页
Chinese Journal of Biomedical Engineering
基金
国家自然科学基金项目( 50 376 0 4 0 )
国家自然科学基金青年基金项目( 50 2 0 6 0 13)
上海市教委重点学科项目
关键词
胸主动脉
冻结过程
热膨胀系数
Biomaterials
Cooling
Thermal expansion
Thermoanalysis
