Constitutive Relations of Nonlinear Thermoelasticity of Anisotropic Bodies

Quasilinear relations for finite reversible deformation of anisotropic materials are obtained using a thermomechanical approach. Free energy is written as a function of temperature and compatible invariants of the logarithmic strain measure and basis tensors. Nonlinear thermomechanical effects including different types of material behavior in tension and compression and the temperature dependence of the elastic tensor are taken into account.     

Preparation of sodium and bisarenechromium fullendes containing esters of ethylene glycol,diethylene glycol,crown ethers,methoxyarenes, and N-ethyl-N-phenylbenzamide

Russian Chemical Bulletin - The sodium and bis(arene)chromium salts of monosubstituted hydrofullerides, containing bis(3,4-dimethoxyphenyl)phenylmethane, 2,6-bis(4-methoxyphenyl)-4-phenylpyridine,...     

TeO<Subscript>2</Subscript>–(NaPO<Subscript>3</Subscript>)<Subscript>6</Subscript> Glass-Forming System

It is suggested to use sodium hexametaphosphate as a new glass-forming agent for tellurite glasses. The limits of the glass-forming region were determined for the TeO₂–(NaPO₃)₆ system, and a selective study of the thermal behavior of the glasses synthesized was carried out by the method differential scanning calorimetry. The optical transmission in the UV, visible, and IR spectral ranges was examined. It was shown that oxides of rare-earth elements can be introduced into the glass, which opens up prospects for application of the system as a matrix for generation of laser light in the 2-μm range, required in fabrication of medical lasers.     

Thermodynamic properties of a liquid crystal carbosilane dendrimer

The temperature dependence of the heat capacity of a first-generation liquid crystal carbosilane dendrimer with methoxyphenyl benzoate end groups is studied for the first time in the region of 6–370 K by means of precision adiabatic vacuum calorimetry. Physical transformations are observed in this interval of temperatures, and their standard thermodynamic characteristics are determined and discussed. Standard thermodynamic functions C_p^°(T), H°(T) ? H°(0), S°(T) ? S°(0), and G°(T) ? H°(0) are calculated from the obtained experimental data for the region of Т → 0 to 370 K. The standard entropy of formation of the dendrimer in the partially crystalline state at Т = 298.15 K is calculated, and the standard entropy of the hypothetic reaction of its synthesis at this temperature is estimated. The thermodynamic properties of the studied dendrimer are compared to those of second- and fourth-generation liquid crystal carbosilane dendrimers with the same end groups studied earlier.     

Thermodynamic properties of triphenylantimony dibenzoate

The temperature dependence of the heat capacity of triphenylantimony dibenzoate Ph₃Sb(OC(O)Ph)₂ is studied in the range of 6–480 K by means of precision adiabatic vacuum calorimetry and differential scanning calorimetry. The melting of the compound is observed in this temperature range, and its standard thermodynamic characteristics are identified and analyzed. Ph₃Sb(OC(O)Ph)₂ is obtained in a metastable amorphous state in a calorimeter. The standard thermodynamic functions of Ph₃Sb(OC(O)Ph)₂ in the crystalline and liquid states are calculated from the obtained experimental data: C_p^°(T), H°(T)–H°(0), S°(T), and G°(T)–H°(0) for the region from T → 0 to 480 K. The standard entropy of formation of the compound in the crystalline state at T = 298.15 K is determined. Multifractal processing of the low-temperature (T < 50 K) heat capacity of the compound is performed. It is concluded that the structure of the compound has a planar chain topology.     

Thermal behavior of polymers prepared using the tri-<Emphasis Type="Italic">n</Emphasis>-butylboron–<Emphasis Type="Italic">p</Emphasis>-quinone system

Thermal behavior of polymers [poly(methyl methacrylate), poly(methyl acrylate), polystyrene] prepared in the presence of tri-n-butylboron and a series of p-quinones was studied. The heat resistance of the polymers increases with an increase in the inhibition constant of the p-quinone taken for the synthesis. The enhancement of the heat resistance of the polymer is due to a decrease in the amount of weak bonds and to the formation of associates.     

The heat capacity and standard thermodynamic functions of Ni<Subscript>0.5</Subscript>Zr<Subscript>2</Subscript>(PO<Subscript>4</Subscript>)<Subscript>3</Subscript> phosphate over the temperature range from <Emphasis Type="Italic">T</Emphasis> → 0 to 664 K

The temperature dependence of the heat capacity of crystalline nickel zirconium phosphate C°_p = f(T) was measured over the temperature range 6–664 K. The experimental data obtained were used to calculate the standard thermodynamic functions of Ni_0.5Zr₂(PO₄)₃ from T → 0 to 664 K. The standard entropy of phosphate formation from simple substances at 298.15 K was calculated from the absolute entropy of the compound. The data on the low-temperature heat capacity were used to determine the fractal dimension of Ni_0.5Zr₂(PO₄)₃ over the temperature range 30–50 K. Conclusions concerning the heterodynamic characteristics of the structure of Ni_0.5Zr₂(PO₄)₃ were drawn.     

The thermodynamic properties of crystalline Sr<Subscript>0.5</Subscript>Zr<Subscript>2</Subscript>(PO<Subscript>4</Subscript>)<Subscript>3</Subscript> phosphate from <Emphasis Type="Italic">T</Emphasis> → 0 to 665 K

The temperature dependence of the heat capacity of crystalline Sr_0.5Zr₂(PO₄)₃ phosphate was studied by precision adiabatic vacuum and dynamic scanning calorimetry over the temperature range 7–665 K. The low-temperature dependence of the heat capacity was analyzed using the Debye theory of the heat capacity of solids and its multifractal generalization, which allowed conclusions to be drawn about the heterodynamic characteristics of the structure. The experimental data obtained were used to calculate the standard thermodynamic functions of Sr_0.5Zr₂(PO₄)₃ from T → 0 to 665 K. The standard absolute entropy of Sr_0.5Zr₂(PO₄)₃ was in turn used to calculate the standard entropy of its formation from simple substances at 298.15 K.