Confirmation of the First Law of Thermodynamics in Theory and Extended Bernoulli Equation

The internal energy change of ideal gas does not depend on the volume and pressure. The internal energy change of real gas has not any relation with the volume and pressure, which had been proved. If the internal energy change had not any relation with the volume and pressure, we could confirm the first law of thermodynamics in theory. Simultaneously, the internal energy change is the state function that shall be able to be proved in theory. If the internal energy change depended on the volume and pressure, we could not prove that the internal energy change is the state function and the chemical thermodynamics theory is right. The extended or modified Bernoulli equation can be derived from the energy conservation law, and the internal energy change, heat, and friction are all considered in the derivation procedure. The extended Bernoulli equation could be applied to the flying aircraft and mechanical motion on the gravitational field, for instance, the rocket and airplane and so on. This paper also revises some wrong ideas, viewpoints, or concepts about the thermodynamics theory and Bernoulli equation.

First-principles calculation of the electronic structure, chemical bonding, and thermodynamic properties of β-US_2

The electronic structure, magnetic states, chemical bonding, and thermodynamic properties of β-US2 are investigated by using first-principles calculation through the density functional theory（DFT） ＋U approach. The obtained band structure exhibits a direct band gap semiconductor at Γ point with a band gap of 0.9 e V for β-US2, which is in good agreement with the recent experimental data. The charge-density differences, the Bader charge analysis, and the Born effective charges suggest that the U–S bonds of the β-US2 have a mixture of covalent and ionic characters, but the ionic character is stronger than covalent character. The Raman-active, infrared-active, and silent modes at the Γ point are further assigned and discussed. The obtained optical-mode frequencies indicate that the three apparent LO–TO（longitudinal optical–transverse optical） splittings occur in B1 u, B2 u, and B3 umodes, respectively. Furthermore, the Helmholtz free energy ？F, the specific heat ？E, vibrational entropy S, and constant volume CVare studied over a range from 0 K-100 K. We expect that our work can provide some valuable information for further experimental investigation of the dielectric properties and the infrared reflectivity spectrum of uranium chalcogenide.

Synthesis of LaGaO_3-Based Electrolyte Material and Its Compatibility with Novel Electrode Materials

La_ 1-xSr_xGa_ 1-yMg_yO_ 3-δ(LSGM)electrolyte material was synthesized by solid-state reaction method. The microstructure characteristics were tested via X-ray diffraction(XRD), scanning electron microcopy (SEM), and energy dispersive spectroscopy (EDS). XRD patterns indicate that perovskite phase began to form when the mixed materials were sintered at 1000 ℃, and the material has a pure LSGM perovskite phase when the mixed materials were sintered at 1450 ℃ in air for 24 h. No chemical reaction between LSGM electrolyte material and La_ 1-xSr_xMn_ 1-yCr_yO_ 3-δ(LSMC) anode material or La_ 1-xSr_xFe_ 1-yCo_yO_ 3-δ (LSFC) cathode material was detected after the mixed materials consisting of LSGM and LSMC or LSFC was sintered at 1200 ℃ in air for 15 h respectively, which shows that LSGM electrolyte material has excellent chemical compatibility with LSMC anode and LSFC cathode materials. According to SEM, LSMC anode film and cathode composite film of LSFC and LSMC prepared using direct painting method by sintering at 1150 ℃ are both porous and well cohered on LSGM electrolyte substrate.

Numerical Study on the Acetylene Concentration in the Hydrogen-Carbon System in a Hydrogen Plasma Torch

Effects of the hydrogen/carbon mole ratio and pyrolysis gas pressure on the acetylene concentration in the hydrogen-carbon system in a plasma torch were numerically calculated by using the chemical thermodynamic equilibrium method of Gibbs free energy. The calculated results indicate that the hydrogen concentration and the pyrolysis gas pressure play crucial roles in acetylene formation. Appropriately abundant hydrogen, with a mole ratio of hydrogen to carbon about 1 or 2, and a relatively high pyrolysis gas pressure can enhance the acetylene concentration. In the experiment, a compromised project consisting of an appropriate hydrogen flow rate and a feasible high pyrolysis gas pressure needs to be carried out to increase the acetylene concentration from coal pyrolysis in the hydrogen plasma torch.

Co-Generation of C_2 Hydrocarbons and Synthesis Gases from Methane and Carbon Dioxide: a Thermodynamic Analysis

This paper deals with thermodynamic chemical equilibrium analysis using the method of direct minimization of Gibbs free energy for all possible CH4 and CO2 reactions. The effects of CO2/CH4 feed ratio, reaction temperature, and system pressure on equilibrium composition, conversion, selectivity and yield were studied. In addition, carbon and no carbon formation regions were also considered at various reaction temperatures and CO2/CH4 feed ratios in the reaction system at equilibrium. It was found that the reaction temperature above 1100 K and CO2/CH4 ratio=1 were favourable for synthesis gas production with H2/CO ratio unity, while carbon dioxide oxidative coupling of methane （CO2 OCM） reaction to produce ethane and ethylene is less favourable thermodynamically. Numerical results indicated that the no carbon formation region was at temperatures above 1000 K and CO2/CH4 ratio larger than 1.

Catalysts and thermodynamic coupling of chemical reactions

The condition of occurrence of the thermodynamic coupling of chemical reactions is analysed from kinetics. It is found that the thermodynamic coupling is impossible for those reactions which obey kinetically the mass action law. The thermodynamic coupling of chemical reactions is further analysed in the case with catalyst. It is found that the thermodynamic coupling which is impossible without catalyst may become possible by introducing proper catalyst into the system. This implies that the catalysts can change not only the rates of chemical reactions, but also the behaviors of thermodynamic coupling of chemical reactions, including the direction of some reactions. Such role of catalysts comes into play not by changing the total free energy of the system, but by changing the reaction mechanism.

Nonzero Solubility Rule

A solubility related rule, nonzero solubility rule, is introduced in this paper. It is complementary to the existing rules such as the “like dissolves like” rule and can be understood on the basis of classical chemical thermodynamics.