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Non-thermal plasma catalysis, as a special heterogeneous catalytic reaction, needs to consider both gas discharge and catalytic reaction. Packed bed dielectric barrier discharge (PB-DBD) is widely used in non-thermal plasma catalysis, but the exact control principle of gas discharge, especially streamer discharge, is not clear. In this study, therefore, the orderly arranged dielectric rods were packed in the discharge gap of PB-DBD, and the streamer discharge behaviors were controlled by adjusting their diameter(s), quantity(ies), location(s) and dielectric constant(s). Al2O3 and ZrO2 dielectric rods with dielectric constants of about 9 and 25 were used as packing material. Pure CO2 was used as reaction gas and discharge gas. Discharge images showed that stable and controllable streamer discharges can be formed between the dielectric rod and ground electrode. The intensity, width and length of the streamer discharge can be significantly changed by optimizing the dielectric constant, diameter, packing number and position of the dielectric rod, thereby affecting the CO2 conversion efficiency. Increasing dielectric constant and the distance between the dielectric rod and ground electrode can increase the intensity of streamer discharge, thus promoting the CO2 conversion efficiency. Compared with an empty reactor, after packing 24 ZrO2 dielectric rods with a diameter of 1 mm, the CO2 conversion and energy efficiency increased from 9.58% to 20.1% and from 1.67% to 2.89%, respectively. In short, this research has important implications for plasma catalysis. This study not only reveals the synergistic characteristics between streamer discharge and CO2 dissociation, but also provides an important idea for structural optimization of PB-DBD catalyst.

Lithium sulfur (Li-S) battery is considered as a promising alternative for the development of battery technologies. However, the shuttle effect seriously limits its practical use. Herein, hollow tubular graphene-like carbon nitride (Tg-C3N4) is synthesized and utilized as a functional interlayer to inhibit shuttling effect and promote catalytic kinetics. Both experiments and DFT calculations together suggest that N-doping enhances the electron transfers between Tg-C3N4and LiPSs, leading to improved chemical adsorptions and catalytic effects towards the redox conversions of the active sulfur species. Besides, Tg-C3N4delivers a unique hollow tubular architecture with massive ion transfer pathways and fully exposed active interfaces. In addition, the abundant C-N heteroatomic structures also impose strong chemical immobilization toward lithium polysulfides. Benefiting from these unique superiorities, the cell with the Tg-C3N4-modified separator exhibits a reversible capacity of 494 mAh g-1after 500 cycles at 1 C with a negligible capacity decay of 0.085% per cycle, indicating an efficient strategy toward high-performance modified separators.

For the furnace temperature curve when heating electronic components in the reflow furnace, with Fourier’s law, the Newton’s cooling law and the law of conservation of energy as the theoretical basis, combined with the relavant data, and based on heat conduction and thermal convection of the welding area, a temperature change model is established, and single objective optimization model is established as well. By using MATLAB and EXCLE to conduct ergodic search algorithm of solving, the ideal temperature curve and velocity of conveyor belt of the furnace is obtained.

A mechanical model that explains the phase behaviors and thermal properties of a liquid crystal (LC) system is developed. We have modeled terphenyl liquid crystalline molecules on the basis of the architecture of a frame consisting of atomic nuclei. It is shown that the thermal stability of the LC molecules is dominated by the rotational dynamics of the nuclei frame. The characteristics of phase stability in a fluorine atom's position isomers in the terphenyl compounds are successfully interpreted with the use of an inertia tensor of the atom nuclei frame. From the observation of novel slim and fat isomers in fluorinated terphenyl LC compounds, we have developed a theory that interprets and predicts the thermal phase stability for novel isomeric LC compounds.

A simulation work on a broad THz absorption of liquid crystal mixture E7 consisting of 5CB, 7CB, 8OCB and 5CT is reported. Based on the density functional theory, the molecular structures of the monomers were optimized and calculated using the Gaussian package with base set B3LYP and 6-311g. The results indicate that the simulation of the characteristic absorption spectra is accurate compared to the experimental and literature report in the infrared band. By analyzing contribution of the benzene ring, C–O and alkyl bonds on THz absorption, it is found that there are no significant effects from the cyano group and the alkyl radical. The addition of a benzene ring leads to an increase in absorption intensity and redshift. By discussing the atomic mass distribution and the structural symmetry of the monomers, a reason for the strong THz absorption of 8OCB is proposed.

This paper reports the doping effect of cholesteric liquid crystal 3β-Hydroxy-5-cholestene 3-oleate on polymer solar cells composed of the poly 3-hexyl thiophene and the fullerene derivative. With a doping ratio of 0.3 wt%, the device achieves an ideal improvement on the shunt resistor and the fill factor. Compared with the reference cell, the power conversion efficiency of the doped cell is improved 24%. The photoelectric measurement and the active layer characterization indicate that the self-assembly liquid crystal can improve the film crystallization and reduce the membrane defect.

This paper investigates the impact of electrode geometry on the performance of polymer solar cells (PSCs). The negative electrodes with equal area (0.09 cm2) but different shape (round, oval, square and triangular) are evaluated with respect to short-circuit current density, open-circuit voltage, fill factor and power conversion efficiency of PSCs. The results show that the device with round electrodes gives the best photovoltaic performance; in contrast, the device with triangular electrodes reveals the worst properties. A maximum of almost a 19% increase in power conversion efficiency with a round electrode is obtained in the devices compared with that of the triangular electrode. To conclude, the electrode boundary curvature has a significant impact on the performance of PSCs. The larger curvature, i.e. sharper electrodes edges, perhaps has a negative effect on exciton separation and carrier transport in photoelectric conversion processes.

The effects of a fluorinated substituent on physical properties of phenyl bicyclohexane liquid crystals (LCs) are reported. Temperature dependence of the physical properties for different terminals and extents of fluorine substituents were compared. Electro optic measurements suggest that the molecular length and position of fluorine strongly influence the threshold voltage and anisotropic dielectric constant. However, the resulting temperature dependences of refractive indices, order parameters and splay elastic constants indicate that the fluorine substituents cause minor differences. The effect of symmetric fluorine substituents on the benzene ring was also discussed.

Three groups of linear molecules, one group having a liquid crystal (LC) phase and two groups having a general state, were prepared to investigate by a mechanical LC system model. The dynamic parameters, the moment of inertia and rotational critical velocity, were calculated to correlate with the appearance of the LC phase. The analysis of the molecular dynamic parameters allows the assessment of why these molecules behave differently in the formation of phase.

A mechanical model is established to explain phase behaviors and thermal properties of liquid crystals (LCs). We postulate that LC phases are micro-machine systems consisting of an ensemble of molecular rotors. The phenomena of the thermal stability of phase and polymorphism are interpreted in terms of mechanics that involve basic parameters such as center of gravity (G), moment of inertia (I A), eccentricity (ε) and mass deviation along the molecular axis (δ). A novel concept of “slim isomer” and “fat isomer” for the fluorinated LC system is proposed. Furthermore, the parameter ωc, critical rotational velocity around the long molecular axis is adopted to analyze the thermal stability at the critical point. It is determined that the value of ωc is a key parameter for the characterization of each homologous series.