p***e
发帖数: 402 | 1 从金属或者半导体,绝缘体转变为超导的那个临界温度? |
e********y
发帖数: 935 | 2 你是不是该给个上下文？
【在 p***e 的大作中提到】
: 从金属或者半导体,绝缘体转变为超导的那个临界温度?
|
p***e
发帖数: 402 | 3 http://news.illinois.edu/NEWS/06/0608uaser.html
倒数第三段.
Nevertheless, uasers may be useful. With their longer wavelengths and more
convenient frequencies, uasers
could prove useful for modeling and studying laser dynamics. They could also
serve as highly sensitive
scientific tools for measuring the elastic properties and phase changes of
modern materials, such as thin films
or high-temperature superconductors.
“Uasers can produce an ultrasonic version of acoustical feedback – an
ultrasonic howl s
【在 e********y 的大作中提到】
: 你是不是该给个上下文？
|
g***e
发帖数: 4074 | 4 相变（phase transition）是很广泛的一个概念，包括structural, magnetic,
superconducting等等。在高温超导中，超导相变经常伴随structure或者磁性的相变。
这些连续的相变往往不在同一温度，但一般认为是相互关联的。
ultrasonic，optics以及很多其他手段对各种相变都sensitive。本质上讲，相变引起
了各种物理属性的改变，材料对ultrasound, photon等的反应也自然不一样。通过这些
研究手段可以了解材料的相变甚至是相变的本质。 |
g***e
发帖数: 4074 | 5 对了，原文没说Phase changes of high-t superconductor吧
结构相变与超导相变共存是在cuprates里就知道的
磁性和超导相变共存于超导中这个方面嘛，cuprates还在argue，但在低掺杂铁基超导
里是确实明显共存的。所以Phase changes of high-t superconductor这个说法也没错
——虽然原文的意思似乎只是指超导的相变温度。 |
f******y
发帖数: 4 | 6 应当是指测相位吧
also
【在 p***e 的大作中提到】
: http://news.illinois.edu/NEWS/06/0608uaser.html
: 倒数第三段.
: Nevertheless, uasers may be useful. With their longer wavelengths and more
: convenient frequencies, uasers
: could prove useful for modeling and studying laser dynamics. They could also
: serve as highly sensitive
: scientific tools for measuring the elastic properties and phase changes of
: modern materials, such as thin films
: or high-temperature superconductors.
: “Uasers can produce an ultrasonic version of acoustical feedback – an
|
c**m
发帖数: 1632 | 7 Apparently it is a technique to measure the acoustic phonon modes of the HTc
materials. I don't know why the coherent excitation of the acoustic phonon
or vibrations could be called a uaser, the analogue of laser. For lasing,
there is spontaneous emission and it is fed into the stimulated emission
mode by light travelling in a resonant cavity. Within this traditional
scenario, the claim is not true.
【在 f******y 的大作中提到】
: 应当是指测相位吧
:
: also
|
