一、引 言 长期以来,绝热材料就是工程师们的一个很重要的研究课题,也是传热技术早期发展中主要涉及的内容之一。然而在60年代以前的数十年中,传热学许多新的研究和发展,使该课题由早期的鼎盛而还渐衰退。大家认为它已发展得相当完善了。已成为一个经典课题,余下的工作仅与设计工程师和制造工程师有关。与此同时,空间技术、核技术、低温技术和其它现代技术的发展已大大突破了常温、高温和低温区的大量工程问题。其中一个主要的问题就 I. INTRODUCTION Insulation materials have long been a very important research topic for engineers and one of the main contents involved in the early development of heat transfer technology. However, in the decades prior to the 1960s, many new researches and developments in heat transfer have led to the gradual decline of the topic from its early peak. Everyone thinks it has developed quite well. Has become a classic topic, the rest of the work is only related to the design engineer and manufacturing engineer. At the same time, the development of space technology, nuclear technology, cryogenic technology and other modern technologies has largely broken through a large number of engineering problems at ambient temperature, high temperature and low temperature. One of the major issues