Si M S, Milner T E, Anvari B, Nelson J S
Beckman Laser Institute and Medical Clinic, University of California, Irvine 92715, USA.
Lasers Surg Med. 1996;19(1):17-22. doi: 10.1002/(SICI)1096-9101(1996)19:1<17::AID-LSM3>3.0.CO;2-T.
A common assumption made in the thermal response of biological materials due to laser irradiation is the constancy of the specific heat capacity at constant pressure, CP. In this investigation, CP of pure hydrated Type I collagen films is measured in time during laser irradiation.
STUDY DESIGN/MATERIALS AND METHODS: A Nd:YAG laser scanning calorimeter is developed and used to test the constant heat capacity assumption by monitoring transient, laser-induced thermal transitions in the collagen films.
Results of preliminary studies on the irreversible, laser induced thermal denaturation of collagen with heating rates of up to 110 K/sec show a broad CP transition that can attain large values (20 J/g K).
The magnitude of the CP change that occurs in response to laser irradiation shows that the assumption of a constant CP when modeling heat transport in tissues is not always valid.
在激光辐照引起生物材料热响应的过程中，一个常见的假设是恒压比热容CP恒定。在本研究中，对纯的水合I型胶原膜在激光辐照期间的CP进行了实时测量。
研究设计/材料与方法：开发了一种Nd:YAG激光扫描量热仪，并通过监测胶原膜中瞬态的、激光诱导的热转变来检验恒热容假设。
对加热速率高达110 K/秒的胶原不可逆激光诱导热变性的初步研究结果显示，CP有一个宽泛的转变，其值可达很大（20 J/g K）。
响应激光辐照而发生的CP变化幅度表明，在对组织中的热传递进行建模时，假设CP恒定并不总是有效的。
