2.(题目略) Cryopreservation of sperm http://www.repromed.com.au/CRYOPRESERVATION.html 大部分都是医疗诊所... Freeze-drying http://www.rpi.edu/dept/chem-eng/Biotech-Environ/LYO/index.html 简言之所谓冻乾大概就是 先冷冻 然後再抽真空 把固态的水直接变成气体昇华 Freeze-substitution http://www.biozentrum.unibas.ch/~izmb/atlas/htm/t19.htm 在结冻的状态下 以有机溶液置换固态水 Freezr fracture 跟 Freeze etching 我是看课本的 第14章 CryoSEM http://www.gatan.com/faq/cryo_alto.html http://www.biotech.ufl.edu/sems/echlin.230.PDF 低温扫描式电子显微镜 可以用来观察hydrated sample 有点像environmentalsem之类 --method 1. The sample is mounted on to the appropriate sample holder and then plunge frozen, usually into liquid nitrogen. 2. The sample holder is then withdrawn, under vacuum, into a vacuum transfer device for transfer to the cryo-preparation chamber. 3. After transfer to the (separately pumped) cryo-prep chamber the sample is maintained at a low temperature and low contamination conditions. 4. The sample may be fractured and/or freeze etched (by controlling tempera- ture raise until sublimation can occur) to expose internal structure. 5. Finally a thin conductive coating is usually applied to allow high resolu- tion imaging or microanalysis in the SEM.. Transfer to the SEM chamber is via an interlocked airlock and onto a cold stage module fitted to the SEM stage. --application To study the microstructure of hydrated samples. All of the biological sciences, especially botany, mycology, agricultural sciences, biotechnology and bio-medical. Related to the above are applications in the pharmaceutical, healthcare and cosmetics industries, also R&D and QA of products e.g. drug delivery, cream preparations, dressings. Applications in food technology including emulsions, suspensions, multi-phase products e.g. ice cream, dairy products, texture, keeping properties and spoiling organisms.Other industries using cryo-SEM include oil, chemical, paper and other forest products, textiles, paint, printing and cement. --limitation Low vacuum or low energy electron beam may sacrifice resolution. Beam damage, with mass loss being the principle concern. Electron irradiated ice is a rich source of free radicals. --

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