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C2H4 is used as an indicator gas to evaluate the spontaneous combustion process of coal, and the adsorption of C2H4 by coal will cause the decrease of C2H4 gas volume fraction in mine air, which in turn affects the accuracy of the assessment of the spontaneous combustion process of coal. In order to reveal the microscopic mechanism of C2H4 adsorption in bituminous coal, a molecular model of Wiser bituminous coal was constructed, and the adsorption process of C2H4 in the molecular model of bituminous coal at temperature of 293.15-313.15 K and pressure of 0.1-3 MPa was simulated using Monte Carlo method, and the changes of adsorption heat, adsorption potential energy and adsorption entropy during the adsorption process were analyzed. The results showed that the adsorption of C2H4 in bituminous coal molecules first increased rapidly with increasing pressure and then leveled off; the higher the temperature, the lower the adsorption of C2H4 when the pressure was the same; Langmuir-Freundlich model has the best fitting effect on C2H4 adsorption process, and the maximum adsorption a of C2H4 decreases with increasing temperature; the average heat of adsorption of C2H4 under different temperature conditions is 35.29-37.65 kJ/mol, indicating that the adsorption of C2H4 in bituminous coal is physical adsorption; the adsorption potential energy and entropy of C2H4 decreased more...

Doxorubicin-loaded PLGA nanoparticles (DOX-PLGA NPs) was prepared by double emulsion (W/O/W) solvent evaporation method with the biodegradable materials-poly (lactic-co-glycolic acid) (PLGA) used as carrier materials. Single-factor test was used to investigate the influence of the type and ratio of the organic phase, the amount of surfactant, PLGA concentration, the ratio of external water phase and oil phase (W/O), the ratio of doxorubicin and PLGA, ultrasonic time and stirring time on the preparation of nanoparticles. The best formulation and preparation conditions were optimized by orthogonal test based on single-factor test, evaluation indicator as particle size and entrapment efficiency, and the results were analyzed by overall desirability. And the in vitro release behaviors of the nanoparticles were studied as well. The size distribution, zeta potential, morphology of DOX-PLGA NPs were characterized by laser light scattering and transmission electron microscopy; encapsulation efficiency and releasing behavior of DOX-PLGA NPs in vitro were investigated by ultraviolet spectrophotometry. The results show that the DOX-PLGA NPs are regularly spherical in shape with the mean size of (189.2 +/- 5.3) nm, and the zeta-potential of the NPs is about (-28.32 +/- 0.52) mV. Drug loading and encapsulation efficiency are estimated to be (73.16 +/- 0.43) % and (1.51 +/- 0.07) %, respectively. The cumulative percentage of the drug released is 90.34%, and the in vitro release behavior made up of initial burst release and sustained-release could be described by the bidirectional kinetic equation. The results indicate that hydrophilic small-molecule drugs could be successfully entrapped into PLGA-NPs. With optimization of the formulation and preparation conditions, we obtained uniform and stable DOX-PLGA NPs with sustained release character in vitro and pH-sensitive property, which could provide the experimental basis for the development of a new anti-tumor sustained-release formulation. more...