Task: Text Categorization
Input (English): In a paper concerning "Nilpotent Energies" in the theory of these materials, Ericksen explores a modulus undetermined in the Oseen-Frank hydrostatic theory of these materials. A statistical model of these materials relies on applying the molecular field approximation on a weak anisotropic pair potential and can easily be made more accurate by including terms for deviations from cylindrical symmetry, called Maier-Saupe theory. In one phase of these materials, named for its thread-like defects also called disinclinations, particles display orientational but no positional order. The layered and positionally ordered smectic phase, thus, contrasts with the higher-temperature nematic phase. The phase transitions of one class are modeled in the Onsager hard-rod model, and those "lyotropic" ones resemble the properties of some block copolymers, since they behave like these materials only in the appropriate concentration range. For 10 points, identify this class of substances that display an intermediate phase of matter by both flowing and exhibiting regular structure, notable for being used in flatscreen displays.
Output (English): Science