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1.
ABSTRACTWe have studied the effect on the structural, electronic, elastic and transport properties of binary skutterudite CoX3 (X?=?P, As, Sb) after filling void spaces by Pr atoms. All the calculations are carried out using the full-potential linearised augmented plane wave (FP-LAPW) method within the generalised gradient approximation (GGA) viz, PBE, and PBEsol. In case of binary skutterudites, equilibrium lattice parameters obtained using PBEsol functional are in good agreement with the theoretical and experimental results. The Hubbard parameter (U) has been used with PBEsol-GGA functional to see its effect on the band structures of binary and ternary compounds. Filling of Pr atoms at void positions in binary skutterudites creates the gap between the valence and conduction band. The obtained values of the elastic constants show that CoX3, PrCo4X12 (X?=?P, As, Sb) are mechanically stable and brittle. Mechanically, PrCo4P12 and PrCo4As12 are anisotropic, but PrCo4Sb12 is isotropic. Obtained saturated Seeback coefficients are approximate ?60?μV/K (PrCo4P12), ?80?μV/K (PrCo4As12) and ?68?μV/K (PrCo4Sb12) in the spin-up channel while in the spin-down channel corresponding values are ?10, ?50 and ?120?μV/K at 800?K, respectively. These values are higher in magnitude than that in the corresponding binary compounds. 相似文献
2.
Synthesis,physicochemical, and biological activities of novel N‐acyl tyrosine monomeric and Gemini surfactants in single and SDS/CTAB–mixed micellar system
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Nausheen Joondan Sabina Jhaumeer‐Laulloo Prakashanand Caumul Matthew Akerman 《Journal of Physical Organic Chemistry》2017,30(10)
A series of single‐chained N‐acyl tyrosine surfactants with varying chain lengths (C10‐C18) and degree of unsaturation, as well as an N‐acyl Gemini tyrosine surfactant with chain length C12, were synthesized, and the structures were confirmed using spectral analysis. The effect of chain length and level of unsaturation on the physicochemical and antibacterial properties of the N‐acyl tyrosine surfactants was evaluated. The C12 derivative displayed the optimum antibacterial activity among the single chain surfactants, and the presence of double bond in the oleoyl derivative enhanced the antibacterial activity over its saturated analogue. The N‐acyl Gemini surfactant displayed the highest antibacterial activity among the series and also showed greater micelle forming ability than its single chain analogue. Mixed micellar behavior of the N‐acyl Gemini surfactant with conventional cationic (CTAB) and anionic (SDS) surfactants in aqueous solution was studied. The negative value of the interaction parameter β12 observed for the N‐acyl Gemini in binary mixture with CTAB surfactant indicated a synergistic interaction within the mixed micellar system. However, the binary mixture with SDS displayed antagonistic behavior. The binary mixture of N‐acyl Gemini surfactant with CTAB displayed better antibacterial activity and foaming properties than with SDS mixtures. Optimum antibacterial activity was observed for N‐acyl Gemini surfactant with mole ratio 0.4 to 0.6 in the CTAB binary mixture, at which the lowest ocular irritation index was observed. Overall, the study showed that the Gemini surfactant in combination with the conventional surfactant CTAB can be used as potential ingredients in detergent and pharmaceutical formulations. 相似文献
3.
Tzu-Huai Yang Shingjiang Jessie Lue 《Journal of Macromolecular Science: Physics》2013,52(7):1009-1029
The sorption behaviors of aqueous ethanol solutions in a polydimethylsiloxane (PDMS) membrane at 25°C were investigated in this study. The sorption isotherms for the ethanol and water binary mixtures were experimentally determined. The water uptake reached a maximum at a concentration of 80 wt% ethanol, and the partial water uptakes were even higher than the pure water solubility for 10–95 wt% ethanol solutions in the PDMS membrane, which implies the presence of a strong synergistic effect due to the ethanol copermeant. The Flory-Huggins equation was utilized to predict the sorption levels at various ethanol/water compositions. The binary Flory-Huggins interaction parameters obtained from pure solvent sorption experiments (χiM ) and the ethanol/water vapor liquid equilibrium data (χ 12) were used in the construction of the model for predicting the partial penetrant solubilities. Using constant χij parameters could not render satisfactory predictions; therefore, concentration-dependent expressions for either χ 12 or χiM were employed to improve the prediction power. We found that constant or concentration dependent χ 12 parameters had little impact on the predicted sorption, whereas the modified concentration-dependent χiM values greatly improved the modeling precision. 相似文献
4.
The solvatochromic behavior of the 1,4-bis(((2-methylthio) phenylimino)methyl) benzene [BMTPMB] in single solvents and binary
mixtures were investigated. Fluorescence spectra show the dual emission due to twisted intramolecular charge transfer (TICT)
state. The preferential solvation parameters: local mole fraction, X2L, solvation index δs2, exchange constant K12 were calculated for the binary mixtures, ACN+MEOH, DMSO+CCl4 and CCl4+1,2 DCE. The dipole moment ratios between ground and excited states were deduced using the solvatochromic shifts of absorption
and fluorescence spectra as a function of dielectric constant (ε), refractive index (n) and it was found to be 1.25. 相似文献
5.
V. V. Zelenov E. V. Aparina A. V. Chudinov S. A. Kashtanov 《Russian Journal of Physical Chemistry B, Focus on Physics》2010,4(3):399-407
The reactive uptake of NO3 radicals on the surface of wetted individual X salts and of wetted X-NaCl salts (X = MgCl2 · 6H2O and MgBr2 · 6H2O) at [H2O] = 2 × 1012−2 × 1015 cm−3 and NO3 (4.8 × 1012 cm−3) was studied using a reactor with a movable insert covered with a salt coating in combination with a mass spectrometer for
monitoring the initial reactant and products. The probabilities of NO3 uptake γ on X-NaCl binary salts as functions of the content of doping salt were determined. A parametric approximation of
the experimental data was proposed, which makes it possible to quantitatively predict the extent of surface enrichment of
a wetted binary salt coating in doping salt and its dependence on the humidity and the content of this salt in the binary
mixture. It was established that the relative surface density σX of X doping salt depends on its mole fraction μX in the X-NaCl binary salt as σX = aμX (a = 2.2 for MgBr2 and 13.1 for MgCl2) over the entire humidity range covered. The contributions of the X salts to the overall uptake of NO3 at NO3 concentration typical of the tropospheric conditions ([NO3] ∼ 107 cm−3 and relative humidities of RH ≤ 20%) were estimated. 相似文献
6.
Monte Carlo simulation and theory are used to calculate the excess thermodynamic properties of binary mixtures of spherical Lennard-Jones molecules. We study the excess functions of three binary mixtures characterized by the following size and dispersive energy ratios: (1) (σ22/σ11)3 = 2 and ?22/?11 = 2; (2) (σ22/σ11)3 = 1 and ?22/?11 = 1/2 and (3) (σ22/σ11)3 = 1/2 and ?22/?11 = 2. In all cases, the unlike size parameter, σ12, is kept constant and equal to the value given by the Lorentz combining rule (σ12 = (σ11 + σ22)/2). However, different unlike dispersive energy parameter values are considered through the following combining rules: (a) ?12 = (?11?22)1/2 (Berthelot rule); (b) ?12 = ?11 (association); and (c) ?12 = ?22 (solvation). The pressure and temperature dependence of the excess volume and excess enthalpy is studied using the NpT Monte Carlo simulation technique for all the systems considered. Additionally, the simplest conformal solution theory is used to check the adequacy of this approach in predicting the excess properties in a wide range of thermodynamic conditions and variety of binary mixtures. In particular, we have applied the van der Waals one-fluid theory to describe Lennard-Jones binary mixtures through the use of the Johnson et al. [1993, Molec. Phys., 78, 591] Helmholtz free energy. Agreement between simulation results and theoretical predictions is excellent in all cases and thermodynamic conditions considered. This work confirms the applicability of the van der Waals one-fluid theory in predicting excess thermodynamic properties of mixtures of spherical molecules. Furthermore, since binary mixtures of spherical Lennard-Jones molecules constitute the reference fluid to be used in perturbation theories for complex fluids, such as the statistical association fluid theory (SAFT), this work shows clearly the applicability of the conformal solution theory within the framework of SAFT for predicting excess functions. 相似文献
7.
Values of the binary absorption coefficient μ12 in the induced Herzberg III band of oxygen for O2-Ar and O2-N2 pairs have been obtained for the first time in the range 200–215 nm and in the temperature interval 295–120 K. It has been found that, as the temperature decreases, the binary absorption coefficient increases continuously: for O2-Ar pairs, a marked increase in μ12 starts immediately from room temperature, and, for O2-N2 pairs, it begins at temperatures below 180 K. As the temperature decreases from room temperature to 120 K, μ12 increases roughly by 40 and 35% for O2-Ar and O2-N2 pairs, respectively. For each type of pairs, the dependence μ12(T) has been calculated with the use of the dipole moment function of the induced transition, taking into account both short-and long-range interactions, as well as the multiparametric isotropic potential of intermolecular interactions. It is shown that it is possible to select such parameters of the dipole moment function of the transition that the theoretical curve μ12(T) describes satisfactorily the experimental data on the temperature dependence of μ12 in the Herzberg III band for O2-Ar and O2-N2 pairs in the whole temperature range under study. 相似文献
8.
Aditya M. Vora 《Journal of Physics and Chemistry of Solids》2007,68(9):1725-1729
The computations of the static and vibrational properties of four equiatomic Na-based binary alloys viz. Na0.5Li0.5, Na0.5K0.5, Na0.5Rb0.5 and Na0.5Cs0.5, to second order in local model potential is discussed in terms of real-space sum of Born von Karman central force constants. The local field correlation functions due to Hartree (H), Ichimaru-Utsumi (IU) and Sarkar et al. (S) are used to investigate the influence of the screening effects on the aforesaid properties. Results for the lattice constants C11, C12, C44, C12-C44, C12/C44 and bulk modulus B obtained using the H-local field correction function have higher values in comparison with the results obtained for the same properties using IU- and S-local field correction functions. The results for the Shear modulus (C′), deviation from Cauchy's relation, Poisson's ratio σ, Young modulus Y, propagation velocity of elastic waves, phonon dispersion curves and degree of anisotropy A are highly appreciable for the four equiatomic Na-based binary alloys. 相似文献
9.
Transport properties of a binary mixture of CO2ben N2 from the pair potential energy functions based on a semi-empirical inversion method
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The potential energy surface of a CO2-N2 mixture is determined by using an inversion method, together with a new collision integral correlation [J. Phys. Chem. Ref. Data 19 1179 (1990)]. With the new invert potential, the transport properties of CO2-N2 mixture are presented in a temperature range from 273.15 K to 3273.15 K at low density by employing the Chapman-Enskog scheme and the Wang Chang-Uhlenbeck-de Boer theory, consisting of a viscosity coefficient, a thermal conductivity coefficient, a binary diffusion coefficient, and a thermal diffusion factor. The accuracy of the predicted results is estimated to be 2% for viscosity, 5% for thermal conductivity, and 10% for binary diffusion coefficient. 相似文献
10.
Using the example of a disordered A y B 1 ? y solid solution whose atoms are distributed over squarelattice sites, it is shown that correlations in the first coordination shell inevitably cause correlations in the second and more distant coordination shells. These induced correlations decay with distance extending to the ninth coordination shell in a square lattice. The induced correlations are calculated as a function of the correlation in the first coordination shell for binary solid solutions with various compositions. This dependence is described by a third-degree polynomial in the first-shell correlation to within the computational accuracy. The coefficients of the polynomial calculated in this paper using computer simulation can be useful in developing short-range order theory and in calculating the phase diagrams of binary solid solutions. 相似文献
11.
We present results of calculations of the equilibrium surface tension and density profiles for the liquid-vapour interface of a binary mixture of Lennard-Jones 12-6 fluids. The calculations are based on a density-functional theory for the Helmholtz free energy of the inhomogeneous mixture. This is a ‘microscopic’ generalization of the van der Waals-Cahn-Hilliard theory for the interface of a binary mixture. Our calculations cover the full range of liquid-vapour coexistence and the whole range of concentration. We find a correlation between the excess surface tension of the mixture and the surface segregation (adsorption) of the species with the lower surface tension. The ways in which segregation and excess surface tension depend on the Lennard-Jones parameters of the pure components are briefly discussed. Our results for the excess surface tension of mixtures of Ar and N2 and Ar and CH4 are compared with experiment; the agreement is reasonable. 相似文献
12.
Nd2O3-SiO2 binary oxide was prepared by solgel technique using tetra-ethoxysilane and neodymium nitrate as precursor materials and HCl as a catalyst. The prepared samples were subjected to heat treatment in the temperature range from 600 to 1100 °C for different time duration. Characterization of heat treated samples was carried out by using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The effect of sintering temperature and time on structural changes of Nd-doped silica has been discussed. The sample sintered at 1100 °C for 12 h shows the formation of monoclinic Nd2O3 nanocrystallites in silica matrix with average grain size ∼18 nm. 相似文献
13.
A molecular dynamics (MD) simulation study has been performed for the rapid solidification of Cu70Ni30 adopting the quantum Sutton-Chen many-body potentials. By analyzing the bond-types and the relation of atomic average energy
versus temperature, it was demonstrated that as cooling rate being 2×1012 K/s, the Cu70Ni30 formed fcc crystal structures and freezing point was found. In addition, having analyzed the transformation of microstructures
and the detail of crystal growth by using atomic trace and visual method, not only could the formation of binary disordered
solid solution be showed, but also the solidification of liquid metals and the crystal growth processes could be, further
understood. 相似文献
14.
Young-Joo Eo Wonha Lee Kyunhwan Kim SeJin Ahn Ara Cho Jihye Gwak Kyunghoon Yoon Se Youn Moon Hyo Rim Jung Jin Hyeok Kim Jae Ho Yun 《Current Applied Physics》2014,14(10):1349-1355
Carbon-free CuInSe2 (CIS) thin film with a dense microstructure has been prepared using a novel non-vacuum based fabrication route. CuxSy and In2Se3 binary nanoparticles, approximately 10 nm in size, were synthesized by a low temperature colloidal process. The precursor film was deposited using the coating ink formulated with the binary nanoparticles and pyridine, and then annealed in the rapid thermal annealing (RTA) chamber at 540 °C for 15 min under selenium (Se) atmosphere. Scanning electron micrographs, X-ray diffraction patterns and Raman spectra showed a phase pure carbon-free and dense CIS thin film was prepared in this method. A solar cell device fabricated using this CIS thin film showed the following photovoltaic characteristics: VOC = 350 mV, JSC = 24.72 mA cm−2, FF = 38.73% and η = 3.36% under standard AM 1.5 condition. 相似文献
15.
A molecular dynamics (MD) simulation study has been performed for the rapid solidification of Cu70Ni30 adopting the quantum Sutton-Chen many-body potentials. By analyzing the bond-types and the relation of atomic average energy
versus temperature, it was demonstrated that as cooling rate being 2×1012 K/s, the Cu70Ni30 formed fcc crystal structures and freezing point was found. In addition, having analyzed the transformation of microstructures
and the detail of crystal growth by using atomic trace and visual method, not only could the formation of binary disordered
solid solution be showed, but also the solidification of liquid metals and the crystal growth processes could be, further
understood. 相似文献
16.
The Loschmidt technique has been used to measure the pressure dependence at two temperatures of the binary diffusion coefficients of the systems N2-Ar, N2-O2, O2-Ar and Ar-Kr; gas mixtures were analysed with a mass spectrometer. The results for the first three systems indicate that the first term of the Thorne-Enskog theory for moderately dense gases is not adequate to describe binary diffusion in these systems. Because the quantity (n12) is a linear function of the number density in all cases, higher order terms need not be considered. 相似文献
17.
Low-field microwave absorption has been used to discriminate between the YBa2Cu3O7?σ high temperature superconductor synthesized by reacting the binary metal oxides, BaCuO2 and Y2Cu2O5, versus synthesis with a single metal oxide route. This discrimination is more clearly seen by microwave absorption than by resistance measurements. Supplementary data was obtained by electron spin resonance in the g=2 region, scanning electron microscopy, thermal analysis and x-ray diffraction techniques. The scanning electron micrographs indicate a more separated granular structure for the material synthesized from the binary oxides. The low field non-resonant microwave absorption, which is characteristic of the superconducting phase, is twice as intense for the binary metal oxide preparation as compared to the single metal oxide preparation. Also, the superconducting transition temperature seems to be several degrees higher for the binary oxide preparation. 相似文献
18.
《Journal of Molecular Liquids》2006,123(2-3):92-104
Dielectric relaxation and dipole moment of binary mixtures of homologous series of mono alkyl ethers of ethylene glycol and of diethylene glycol, i.e., mono methyl, mono ethyl and mono butyl ethers of ethylene glycol (ROCH2CH2OH) and mono methyl, mono ethyl and mono butyl ethers of diethylene glycol (ROCH2CH2OCH2CH2OH) with ethyl alcohol (C2H5OH) of different concentrations were studied in dilute solutions of benzene, dioxane and carbon tetrachloride at 35 °C. Permittivity (ε′) and loss (ε″) at 10.1 GHz, static dielectric constant εo at 1 MHz and high frequency limiting dielectric constant ε∞ = nD2 at optical frequency of these molecules and their binary mixtures at different concentration were measured in dilute solutions of non-polar solvents. The average relaxation time τo, relaxation times corresponding to overall molecular reorientation τ1 and group rotations τ2 were determined using Higasi's single frequency measurement equations for dilute solutions. The evaluated values of relaxation times and free energy of activation ΔF were used to explore the solvent effect on molecular dynamics of these polar binary systems in non-polar solvents. The excess inverse relaxation time and excess free energy of activation were determined to confirm the existence of hydrogen-bonded heterogeneous cooperative domains of the ethers and alcohol molecules at different concentration their binary mixtures in non-polar solvents. The dipole moment of the binary mixtures was evaluated using Higasi's and Guggenheim's equation for dilute solutions. The evaluated values of dipole moments and computed dipole moment values using a simple mixing equation of the polar molecules binary mixture were used to explore the effect of non-polar solvent environment on heterogeneous molecular interactions between ethers and alcohol molecules. The effect of number of carbon atoms in the molecular structure of these homologous series molecules was also considered for the interpretation of various evaluated dielectric parameters. 相似文献
19.
Yu. A. Bogdanova S. A. Gubin S. B. Viktorov A. V. Lyubimov V. A. Shargatov 《Russian Physics Journal》2010,53(2):114-122
Analytical expressions are derived and a computational algorithm and program for calculating distribution functions of rigid
spheres g
ij
(r) necessary for calculations of the thermodynamic parameters of a binary fluid mixture are developed in the context of perturbation
theory using the procedure based on the inversion of the Laplace transform for functions rg
ij
(r) obtained from the Percus–Yevick equation. 相似文献