Thermal Conductivity of Solid Triphenyl Phosphite.

The thermal conductivity, , of solid triphenyl phosphite was measured by using the transient hot-wire method, and its temperature and pressure dependencies were analyzed to understand heat transfer processes in the solid polymorphic phases, as well as in the glass and the exotic glacial state. Phase transformations and the structural order of the phases are discussed, and a transitional pressure-temperature diagram of triphenyl phosphite is presented. The thermal conductivity of both the crystalline and disordered states is described within the theory of two-channel heat transfer by phonons and diffusons in dielectric solids.

Role of Optical Phonons and Anharmonicity in the Appearance of the Heat Capacity Boson Peak-like Anomaly in Fully Ordered Molecular Crystals.

We demonstrate that the heat capacity Boson peak (BP)-like anomaly appearing in fully ordered anharmonic molecular crystals emerges as a result of the strong interactions between propagating (acoustic) and low-energy quasi-localized (optical) phonons. In particular, we experimentally determine the low-temperature (<30 K) specific heat of the molecular crystal benzophenone and those of several of its fully ordered bromine derivatives. Subsequently, by means of theoretical first-principles methods based on density functional theory, we estimate the corresponding phonon dispersions and vibrational density of states.

The 5-year dynamics of cardiac structure and function in patients with coronary artery disease after myocardial revascularization.

Objective: The aim: To estimate the dynamics of echocardiographic parameters in patients with CAD within 5 years after revascularization.

Patients And Methods: Material and methods: 50 persons (males/females 39/11; mean age 59.9±9.

Thermal properties of halogen-ethane glassy crystals: Effects of orientational disorder and the role of internal molecular degrees of freedom.

The thermal conductivity, specific heat, and specific volume of the orientational glass former 1,1,2-trichloro-1,2,2-trifluoroethane (CCl2F-CClF2, F-113) have been measured under equilibrium pressure within the low-temperature range, showing thermodynamic anomalies at ca. 120, 72, and 20 K. The results are discussed together with those pertaining to the structurally related 1,1,2,2-tetrachloro-1,2-difluoroethane (CCl2F-CCl2F, F-112), which also shows anomalies at 130, 90, and 60 K.

Thermal properties and Brillouin-scattering study of glass, crystal, and "glacial" states in n-butanol.

We investigated through noncommercial calorimetry and elastoacoustic Brillouin experiments the phase diagram of n-butanol and measured the specific heat and the thermal conductivity in a wide low-temperature range for its three different states, namely, glass, crystal, and the so-called "glacial" states. The main aim of the work was to shed light on the controversial issue of these allegedly polyamorphic transitions found in some molecular glass-forming liquids, first reported to occur in triphenyl phosphite and later in n-butanol. Our experimental results show that the obtained glacial state in n-butanol is not a homogenous, amorphous state, but rather a mixture of two different coexisting phases, very likely the (frustrated) crystal phase embedded in a disordered, glassy phase.

Thermal conductivity of tetrahydrofuran hydrate.

The thermal conductivity of tetrahydrofuran hydrate has been measured in the temperature region 2-220 K by the steady-state potentiometric method. The temperature dependence of the thermal conductivity exhibits behavior typical of amorphous substances. It is shown that above 100 K the mean free path of the phonons is considerably smaller than the lattice parameter and is no longer dependent on temperature.