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Three kinds of bacterial strains, HJ-1, HJ-2, and HJ-3, were isolated by means of enrichment culture from oily sludge in Shengli oil field. HJ-1 was identified as Bacillus by primary test. The influence of seed age, oil concentration, microbial quantity experimental time, and pH on the degradation ability of the HJ-1 strains was investigated. The results showed that the oil reduction rate was 69.4% for the refinery oily sludge, and the conditions were as follows:  50 mL, pH 9, oil concentration 5 g·L-1 enrichment culture of crude oil, addition of 12 mL of strain HJ-1 at the seed age of 16 h, experimental time 6 days, then evaluate the fermentation of hydrocarbon-degrading strain HJ-1 in a shake flask. The influencing factors of pH, microbial quantity, glucose concentration, salt concentration, rotation speed, and temperature were also studied. The oil degradation rate of HJ-1strains rose from 78.6% to 82.0% for crude oil and from 69.4% to 77.4% for oily sludge from the refinery, as the fermentation bacteria solution was added into the oily sludge under the optimum conditions.

Plasmonically induced transparency (PIT) in a multicavity-coupled graphene-based waveguide system is investigated theoretically and numerically. By using the finite element method (FEM), the multiple mode effect can be achieved, and blue shift is exhibited by tunable altering the chemical potential of the monolayer graphene. We find that the increasing number of the graphene rectangle cavity (GRC) achieves the multiple PIT peaks. In addition, we find that the PIT peaks reduce to just one when the distance between the third cavity and the second one is 100 nm. Easily to be experimentally fabricated, this graphene-based waveguide system has many potential applications for the advancement of 3D ultra-compact, high-performance, and dynamical modulation plasmonic devices.

Metasurface lenses are typically investigated for a lot of characteristics, but the design method for conventional devices is comparatively simple in terms of controlling the quantity, position, and size of focal spots. Herein, ultra-thin-phase metasurface structures based on complementary square-split-ring (SSR) nanoantennas have been proposed to achieve terahertz (THz) optical metalenses with multidimensionality and multifocusing. The principle of beam propagation and efficient transmission can be effectively explained through the Fabry-Pérot resonance mode. The THz metalens can efficiently transfer linear crosspolarization under the effects of gratings in the incident plane. By locally tailoring edge lengths and opening the angles of the split rings, full control over abrupt phase changes can be achieved. Two symmetrically distributed parallel focal spots and two vertical focal spots with arbitrary distance can be obtained by arranging the SSR units on the metalenses. Furthermore, we apply the concept of a partitioned-phase mode to realize a double-focusing metalens in the longitudinal direction, which provides a flexible and convenient method to achieve the desired focusing properties. The simulation results are expected to pave the way for practical use of metasurfaces in optical holography, optical-information coding, and parallel-particle trapping.