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71.
72.
R. Singh R. M. Misra D. C. Gupta D. D. Shukla M. N. Sharma M. P. Madan 《Zeitschrift für Physik B Condensed Matter》1985,58(2):83-89
The parameterC
1=[(1/K
T
)/P]
T
, which describes the pressure variation of the compressibility, has been examined correlating the thermodynamical and interatomic potential approaches employing fewer approximations than has been usual heretofore. General expressions have been derived forC
1 by including the thermal correction terms, which have generally been ignored in previous studies concerning thermal properties of ionic crystals. The parameterC
1 has also been related to the Grüneisen parameter, , using a relation given earlier. The applicability of the derived equations is investigated and discussed for alkali halides employing few realistic potential forms. A good general accord is found with the available experimental data, which exhibits an essential improvement over other theoretical determinations. 相似文献
73.
Using the Wigner-Kirkwood expansion and bare Lennard-Jones (LJ) (12-6) potential, an effectiveLJ potential is derived, which includes the quantum effects through the expressions of the effective diameter∂(T, λ) and well-depth
(T, λ). We use theWCA perturbation theory to calculate the free energy and pressure for theLJ and effectiveLJ potentials. Simple analytic expressions are given for the reference system and the first order correction calculated. The
results are quite good at high density. The quantum effects on the free energy and pressure are also discussed. 相似文献
74.
K. Nagarajan M. Bhupathy Rajendra Prasad Ziley Singh V. Venugopal D.D. Sood 《Thermochimica Acta》1980,36(1):85-89
The thermal decomposition kinetics of Pr2(SO4)3 to Pr2O2SO4 have been studied by isothermal weight change determination. The reaction was found to obey a linear law up to α = 0.5; beyond α = 0.5 it could be described as a phase-boundary controlled process. A dependence of the activation energy upon the sample weight was observed. The changes in surface area and density which occur during the decomposition are also given. 相似文献
75.
76.
Surface tension measurements can be used to investigate molecular complex formation in liquid solutions for strong and weak
complexes. The association constant and epthalpy for triethylamine-iodine, hexamethylbenzene-tetracyanoethylene and ethanol-iodine
in cyclohexane are 4·55×103, 218 and 0.93M−1 at 25° C and 12·5, 7·7 and 5·1 kcal/mol respectively. These values compare well with those reported in the literature by
other methods. 相似文献
77.
The article reviews in brief, thede novo group additivity approach and, at length, the different topological approaches to obtain predictive and internally consistent
correlations between various properties and structural features of molecules. The stress has mainly been on the molecular
connectivity method. A new rational scheme for nomenclature of connectivity indices of different orders and types is introduced.
The concept of the perturbation connectivity parameter developed by us recently has been applied to obtain correlations for
molar refraction, boiling point, molar volume, heat of atomisation, heat of combustion, heat of vaporisation, magnetic susceptibility
and critical constants of alkanes, alcohols and alkylbenzenes. A comparative study of various approaches reveals that the
present perturbation topological approach has an edge over other similar methods. 相似文献
78.
Complete Separation of ternary mixtures of Ca, Mg and Sr or Ba ions with ammonium chloride and less complete but detectable separation of the same mixtures with ammonium nitrate have been achieved, as well as a few binary separations of the type Ca-Ba, Ca-Sr, Ca-Mg, Mg-Sr and Mg-Ba. 相似文献
79.
Compatibilities of various PVC blends with chlororubber-20 and its graft polyblends have been studied on the basis of our previous findings. It has been found that chlororubber-20 makes compatible blends with PVC, while grafting of styrene, ethyl acrylate or acrylonitrile onto chlororubber-20 generates heterogeneity in their blends with PVC. The behaviour of these blends at the molecular level is reflected in the changes of ultrasonic velocity and absolute viscosity with composition. 相似文献
80.
Molar excess volumes, VE, for pyridine (A) + α-picoline (B), + β-picoline (B) and + γ-picoline (B) and benzene (A) + toluene (B), + o-xylene (B) and + p-xylene (B) and carbon tetrachloride (A) + n-heptane (B) have been measured dilatometrically as a function of temperature and composition and have been utilized to study B—B and B—B—B interactions in the presence of A via the Mayer—McMillan approach. A model has also been presented to account for these B—B and B—B—B interactions. The VE data at 308.15 K have also been analysed in terms of the “graph theoretical” approach which describes the VE data well for all these mixtures at 308.15 K. The “graph theoretical” approach has further been extended to successfully evaluate VE data for a mixture at any temperature, T2, when the VE data at T1 are known. 相似文献