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Since the question is rather vague, I will just give you some key points: Debye's model treats oscillation modes of a solid as sound waves (phonons) with frequency $\omega(\mathbf{k})=v|\mathbf{k}|$ ($v$ the sound velocity). As a result, with this model, Debye shows how the heat capacity is directly related to the rate of change of the energy expectation ...

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The neutron star crust is separated into outer and inner regions. The outer is a crust of neutron-rich nuclei surrounded by degenerate electrons. The inner is similar, but the nuclei are even more neutron-rich and there are degenerate neutrons too. The (qualitative) answer to your question looks at the ratio of electrostatic (Coulomb) energy to the thermal ...

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So, it's probably more boring than you're thinking. What has happened is: within a certain speck of substance, if you fire two photons in, they come out together. Now, light is known to behave differently in substances, with the clearest example being refraction: light "slows down" in certain substances like water and glass, behaving a little bit as if it ...

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Graphene is a single atom thick. Some groups have made multi-layer graphene but it's still very thin. It's generally printed on a board so that it doesn't fall apart. Thicker layers are just graphite which is pencil lead.

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If we were to send a unmannedspaceship through the Sun. What material can survive? A wide variety of materials might survive passing through the outer layer of the sun, but only if the spaceship is big enough, fast enough and has a thick enough sacrificial/ablative shell. If the ship is slow, it doesn't really matter if the hull survives, most stuff ...

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Piezoelectricity, at least in the usual meaning of the word, arises when you deform a material that does not have a centre of symmetry i.e. there is no inversion symmetry. Liquids are amorphous and therefore (on average) isotropic. This means they are inversionally symmetric (about any point in fact) and therefore will not generate piezoelectricity when ...

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Piezoelectricity has been found in liquid crystals too, see for ex. see RB Meyer, Physical Review Letters 22, 918 (1969). To show piezoelectricity, a material needs some degree of anisotropy; thus it would hardly be possible to find piezoelectricity in liquids, which are pretty isotropic.

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