Based on the basic definition of the Fermi energy of degenerate and relativistic electrons, we obtain a special solution to the electron Fermi energy, [Formula: see text], and express [Formula: see text] as a function of the electron fraction, [Formula: see text], and matter density, [Formula: see text]. We obtain several useful analytical formula for [Formula: see text] and [Formula: see text] within classical models and the work of Dutra et al. (2014) (Type-2) in relativistic mean-field theory are obtained using numerically fitting. When describing the mean-field Lagrangian, density, we adopt the TMA parameter set, which is remarkably consistent with the updated astrophysical observations of neutron stars (NSs). Due to the importance of the density dependence of the symmetry energy, [Formula: see text], in nuclear astrophysics, a brief discussion on [Formula: see text] and its slop is presented. Combining these fitting formula with boundary conditions for different density regions, we can evaluate the value of [Formula: see text] in any given matter density, and obtain a schematic diagram of [Formula: see text] as a continuous function of [Formula: see text]. Compared with previous studies on the electron Fermi energy in other studies models, our methods of calculating [Formula: see text] are more simple and convenient, and can be universally suitable for the relativistic electron regions in the circumstances of common neutron stars. We have deduced a general expression of [Formula: see text] and [Formula: see text], which could be used to indirectly test whether one equation of state of a NS is correct in our future studies on neutron star matter properties. Since URCA reactions are expected in the center of a massive star due to high-value electron Fermi energy and electron fraction, this study could be useful in the future studies on the NS thermal evolution.

In this paper, an simulation program of power performance and fuel economy of large commercial vehicle for passenger transportation is programmed, and high credibility of the program is validated by experiment verification. Comprehensive fuel consumption is firstly introduced as the objective function, joint optimization of powertrain parameters is performed by using multi-disciplinary optimization platform Optimus and MATLAB. The result shows optimization efficiency is greatly improved and the outcome has great satisfaction.

A dynamic model of tractor-semitrailer braking in a turn was established in this paper. By comparing the data of tractor-semitrailer test, a high credibility of the simulation model was certified. In this paper, yaw rate gain and folding angle gain were introduced to evaluate the stability of tractor-semitrailer braking in a turn, and the role played by ABS was analyzed. The results show that yaw rate gain and folding angle gain are very comprehensive evaluating indicator, and ABS plays an important role in improving the stability during braking in a turn of tractor-semitrailer.

Chemical reaction kinetic model of hydrogen production from DME partial oxidation by plasma reforming was found. Mole fractions of main products of DME partial oxidation by spark plasma as the function of inlet gas flow rate were calculated at atmospheric pressure and ambient temperature. Comparing the results of calculation and experiment, the model was proved to be correct. The mechanism research was done by the method of sensitivity analysis and rate of production. The reduced mechanism which includes 16 species and 13 radical reactions was done. The calculation results of reduced mechanism and detailed mechanism were close. The result shows that the reduced mechanism can be used in chemical reaction kinetic calculation of hydrogen production from DME partial oxidation by spark plasma reforming.