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Density is a common physical index of petroleum products and is widely measured by the hydrometer method. This paper presents a novel design of temperature measurement method for a petroleum product density analyzer based on the basic functions and main metrological characteristics of the analyzer by referring to the relevant metrological technical specification JJF 1030-2010 and national standard GB/T 1884-2000. The experimental results show that the measurement method is feasible to scientifically evaluate the temperature metrological performance of the petroleum product density analyzer, and can improve the accuracy and reliability of density measurement results of petroleum products.

We study the Landau levels and magneto-optical properties of bulk black phosphorus (BP) subjected to an in-plane magnetic field along the armchair direction based on an effective k ⋅ p Hamiltonian. We analytically obtain the Landau levels by the perturbation method, which agrees well with the results of numerical diagonalization. By using the Kubo formula, we find the magneto-optical transition selection rules and conductance spectra for inter-band transitions are highly anisotropic. In particular, for linearly polarized light along the armchair direction, the magneto-optical transition selection rule is Δ n = 0, where n is the Landau level index. However, for linearly polarized light along the zigzag and stacking direction, the magneto-optical transition selection rules become Δ n = ±1. The magneto-optical conductance excited by linearly polarized light along the armchair direction is two order of magnitude larger than those excited by linearly polarized light along the zigzag and stacking direction because the inter-band coupling only exists in the armchair direction. Our results are useful to detect the band parameters of BP and design magnetically controlled optical devices based on it.

Recently, the secondary use of waste has received increasing attention. The raw material of Xipayi mouth rinse is Turkish gall. During the industrial production of Xipayi mouth rinse, a lot of gall residues are produced. If these drugs are directly discarded, it will cause waste of resources and also bring pressure to the ecological environment. Previous studies have found that the active ingredient content of Turkish gall residues remains high, therefore the residues are still a valuable resource for exploitation. This study aimed to evaluate the effect of the chemical compositions and drying characteristics of Turkish gall residues during microwave vacuum drying (MVD). Different vacuum degrees, sample loads and sample sizes were used to investigate the drying characteristics of Turkish gall residues, and a kinetics model was established to describe the drying characteristics. We determined gallic acid (GA), methyl gallate (MG) and ellagic acid (EA) contents, total phenolic content (TPC) and total sugar content (TSC) of dried Turkish gall residue powder and investigated the influence of different MVD conditions on components. The results showed the good fit of the Page model equation in describing the drying kinetics of Turkish gall residues during MVD. Different conditions of MVD have different effects on the main components of residue. Thus, MVD can be used to desiccate Turkish gall residues. The Page kinetics model predicts the changes in dehydration rate during MVD of Turkish gall residues, providing a proven drying method for gall residues, and provides a theoretical basis for the industrial mass production of pharmaceutical residues.

We study the spin-dependent transport and thermoelectric properties of ferromagnetic zigzag-edge phosphorene nanoribbon with N chains (N-ZPNR) modulated by a perpendicular electric field (PEF). By adopting the Hubbard model Hamiltonian combined with the self-consistent calculation, and using the nonequilibrium Green's function method, we obtain the band structure, spin-dependent transmission coefficients and Seebeck coefficients. It is demonstrated that the bands are split with spin-up and -down ones for both 12- and 13-ZPNR in the ferromagnetic state, and both ZPNRs show spin-semiconducting behavior with the spin gap of value 1 eV. Interestingly, there is an even-odd effect on the spin-dependent transport and thermoelectric properties when a PEF is applied, which originates from the structure symmetry of N-ZPNR and can result in different behavior of edge states for even and odd cases. The electric field lifts the degeneracy of the two edge bands for both spin-up and -down channels in 12-ZPNR, however, it only bends the spin-up edge bands and shifts the spin-down ones upward without splitting in 13-ZPNR. In addition, we find that the spin Seebeck coefficients exhibit wide plateaus and their maximum values can reach unprecedented giant 5 mV K-1 for both ZPNRs. The spin Seebeck coefficients for both ZPNRs decrease gradually as temperature increasing. As the electric field increasing, the value of the plateau in the spin Seebeck coefficient for 12-ZPNR decreases gradually, however, the plateau almost has no variation for 13-ZPNR in this case. This different responses of spin Seebeck coefficients to the PEF between even and odd cases originate from the different edge state responses to the electric field, and we provide the explanation from the corresponding spin-up and spin-down Seebeck coefficients. Our results reveal that ferromagnetic ZPNRs are perfectly spin-polarized, and are promising candidates for spin caloritronics with high efficiency.

We theoretically investigate the Landau levels (LLs) and magneto-capacitance (MC) of monolayer black phosphorus under a perpendicular magnetic field, on which a parabolic potential is applied along with the armchair and zigzag directions, respectively. By both analytically perturbative calculation and numerical diagonalization based on an effective k ⋅ p Hamiltonian, we find that the LLs parabolically depend on the wave vectors and show strong anisotropy as the parabolic potential is applied along with different crystal directions. Specifically, the analytical LLs obtained by perturbative calculation from a decoupled single-band Hamiltonian are in good agreement with the numerical results. Importantly, the LLs are no longer linearly dependent on the magnetic field and level index even in the low energy regime due to the confinement of parabolic potential which repaints the cyclotron orbits. Moreover, the MC spectrum clearly reflects the structure of the LLs and exhibits strong anisotropic oscillating patterns. It can be used to determine the band parameters of phosphorene, i.e., the effective masses and inter-band coupling in the absence of magnetic and electric fields.

This paper evaluated the environmental performance from 2013 to 2018 based on establishing environmental performance assessment system of Chengdu and the correlation of environmental performance increasing rate and GDP increasing rate was analyzed. In addition, Pearson’s correlation analysis on environmental performance index and GDP was carried out by using SPSS and we can see from the results that environmental performance shows an increasing tendency with the growth of GDP, environmental performance increasing rate is lower than GDP increasing rate. And there was no obvious correlation between environmental performance index and GDP (some high economical areas have low environmental performance levels). In another word, the rapid development of the economy does little help to rapidly improve environmental performance level. So Chengdu should pay more attention to protect environment, and be a coordinated development relationship between economy and environment.

We study the variation of electronic property for zigzag-edge phosphorene nanoribbons (ZPNRs) under a perpendicular electric field (PEF). Using the tight-binding Hamiltonian combined with the surface lattice Green's function (GF) approach, we show that the response of edge states to PEF for a N-ZPNR with even- or odd-N (number of zigzag chains) is qualitatively different. The field opens a gap between two edge bands near the Fermi energy for even-N ribbons, but for odd-N ones where the two edge bands are always nearly degenerated. This difference is originally from that the Stark-effect-induced energies at the upper and lower edges for even- and odd-N ZPNRs are different due to the peculiar lattice structure of phosphorene. In consequence, the electronic densities are more localized at the edges driven by the field for even-N ZPNRs but not for odd-N ones. This even–odd effect is also reflected in conductance, which indicates that the odd-N ZPNRs may be more suitable for the usage of field-effect transistor.

Numerical simulation is carried out for gas-solid two-phase flow in a U-beam separator. In this study, the U-beam is altered with the inlet fins in order to improve the performance of the separator. The inlet fin angle of the separator are 30°, 35°, 40°, 45°, 50°, 55 ° and 60°. The governing equations are the Reynolds-Averaged Navier-Stokes equation with the standard k- model and the discrete phase model (DPM) describing the discrete two - phase flow as well as stochastic tracking model. Results show that the pressure drop deviation with fins is within 3% from those without fins. It is found that there is a maximum separation efficiency at the fin angle of 35°. Fin induces generation of a stagnation region which could collect particles and lead to change of vortical structures. The fin induced flow also causes the turbulent intensity inside the baffle to decrease to facilitate separation.

We study the quantum magnetotransport properties at low temperature for n-type monolayer MoS2 under a perpendicular magnetic field within the linear response theory. By using Kubo formula, it is predicted that the valley- and spin-resolved Hall conductance obeys the same rule as that for conventional fermions. However, the first Hall plateau and the longitudinal charge conductance in low energies are fully valley/spin-polarized, which may produce a pure valley/spin current. In the low magnetic field limit, importantly, the resistance as a function of field is in good agreement with the available experiment data. These interesting findings can be tested experimentally and may be useful for valleytronic and spintronic applications.

We present a theoretical investigation on the quantum magnetocapacitance (MC) for n-type monolayer MoS2 under a perpendicular magnetic field. We find that the MC clearly reflects the valley- and spin-resolved Landau levels (LLs). Interestingly, the MC is fully valley- and spin-polarized, which results in perfect square-wave-shaped polarization. This fully valley- and spin-polarized MC, especially the peak corresponding to the lowest LL, may be of great significance in valleytronic and spintronic device applications because it provides a magnetic method to control the electron valley and spin degrees of freedom. The MC behavior as a function of the magnetic field is also discussed.

We study the spatial distribution of electron spin polarization for a gate-controlled T-shaped channel on the surface of a three-dimensional topological insulator (3D TI). We demonstrate that an energy gap depending on channel geometry parameters is definitely opened due to the spatial confinement. Spin surface locking in momentum space for a uniform wide channel with Hamiltonian linearity in the wavevector is still kept, but it is broken with Hamiltonian nonlinearity in the wavevector, like that for two-dimensional surface states widely studied in the literature. However, the spin surface locking for a T-shaped channel is broken even with Hamiltonian linearity in the wavevector. Interestingly, the magnitude and direction of the in-plane spin polarization are spatially dependent in all regions due to the breaking of translational symmetry of the T-shaped channel system. These interesting findings for an electrically controlled nanostructure based on the 3D TI surface may be testable with the present experimental technique, and may provide further understanding the nature of 3D TI surface states.