Plasma Generation and Application in a Laser Ablation Pulsed Plasma Thruster

The laser ablation plasma thruster is a novel electric propulsion thruster, which combined the laser ablation and electromagnetic acceleration. In order to investigate the plasma expansion and ionization in the laser ablation plasma thruster, which was difficult to obtain from experiments, the heat conduction model and fluid dynamics model were established. The heat conduction model was established to calculate the target ablation, taking into account temperature-dependent material properties, phase transition, dielectric transition and phase explosion. The fluid dynamics model was used to calculate the plasma properties, taking into account ionization, plasma absorption and shielding. The ablation plasma velocity, temperature and electron number density were predicted by using the numerical method. The calculated results showed that the peak values of ablation plasma velocity, temperature and electron number density fraction were distributed at the front of the plasma plume. Moreover, the discharge characteristics and thrust performance were tested with different charged energy, structural parameters and propellants. The thrust performance was proven to be improved by electromagnetic acceleration

Double Dome and Reemergence of Superconductivity in Pristine 6R-TaS2 under Pressure

Investigating the implications of interlayer coupling on superconductivity is essential for comprehending the intrinsic mechanisms of high temperature superconductors. Van der Waals heterojunctions have attracted extensive research due to their exotic interlayer coupling. Here, we present a natural heterojunction superconductor of 6R-TaS2 that demonstrates a double-dome of superconductivity, in addition to, the reemergence of superconducting under high pressures. Our first principles calculation shows that the first dome of superconductivity in 6R-TaS2 can be attributed to changes in interlayer coupling and charge transfer. The second superconducting dome and the reemergence of superconductivity can be ascribed to changes in the density of states resulting from Fermi surface reconstruction, in which the DOS of T-layer and S p-orbitals play a crucial role. We have reported the first observation in TMDs that non-metallic atoms playing a dominant role in the reemergence of superconducting and the influence of two Lifshitz transitions on superconducting properties

Antioxidant and Perservation Effect of Aromatic Hydrosol and Its Application in Fresh-Cut Agaricus bisporus (Lange) Sing. Preservation

Polyphenol oxidase (PPO) is one of the most important factors affecting the browning of fresh-cut fruit and vegetable products. In this research, the effect of aromatic hydrosol on the activity of PPO and its biological antioxidant effect were studied. Aromatic hydrosol extracted from 12 kinds of aromatic plants by steam distillation all inhibited the activity of PPO. Eight of the 12 aromatic hydrosols had a significant scavenging effect on 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2’-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation, and 2-phenyl-4,4,5,5-tetramethylimidazoline-3-oxide-1-oxyl (PTIO) radicals. Total antioxidant capacity assay showed that they had strong antioxidant activity. Analysis by electronic nose and gas chromatography-mass spectrometry (GC-MS) showed that terpenoids and aromatic compounds were the major volatile components of aromatic hydrosol. The efficacy of aromatic hydrosol was evaluated in preserving the quality of fresh-cut mushrooms (Agaricus bisporus). The results showed that compared with the control group, the PPO activity in mushrooms treated with aromatic hydrosol was inhibited, and the increase in browning index (BI) was delayed. In addition, total phenol content, hardness, mass loss and total microbial load were effectively controlled. These results indicate that aromatic hydrosol treatment has a positive effect on maintaining the quality of fresh-cut mushrooms

Topology hierarchy of transition metal dichalcogenides built from quantum spin Hall layers

The evolution of the physical properties of two-dimensional material from monolayer limit to the bulk reveals unique consequences from dimension confinement and provides a distinct tuning knob for applications. Monolayer 1T'-phase transition metal dichalcogenides (1T'-TMDs) with ubiquitous quantum spin Hall (QSH) states are ideal two-dimensional building blocks of various three-dimensional topological phases. However, the stacking geometry was previously limited to the bulk 1T'-WTe2 type. Here, we introduce the novel 2M-TMDs consisting of translationally stacked 1T'-monolayers as promising material platforms with tunable inverted bandgaps and interlayer coupling. By performing advanced polarization-dependent angle-resolved photoemission spectroscopy as well as first-principles calculations on the electronic structure of 2M-TMDs, we revealed a topology hierarchy: 2M-WSe2, MoS2, and MoSe2 are weak topological insulators (WTIs), whereas 2M-WS2 is a strong topological insulator (STI). Further demonstration of topological phase transitions by tunning interlayer distance indicates that band inversion amplitude and interlayer coupling jointly determine different topological states in 2M-TMDs. We propose that 2M-TMDs are parent compounds of various exotic phases including topological superconductors and promise great application potentials in quantum electronics due to their flexibility in patterning with two-dimensional materials

Microbial Intervention as a Novel Target in Treatment of Non-Alcoholic Fatty Liver Disease Progression

Background/Aims: Emerging evidence suggests a close link between gut microbiota and non-alcoholic fatty liver disease (NAFLD). In this study, we aimed to investigate the association between gut microbiota and the DNA methylation of adiponectin (an adipocyte-specific adipocytokine) in rats, following diet-induced NAFLD. Methods: 50 male SD rats were randomly divided into five groups with or without a high fat diet (HFD), antibiotics, and probiotics, in order to establish an imbalanced gut microbiota and probiotic treatment model in NAFLD rats. After 13 weeks of treatment, blood, liver, and cecal tissue samples were collected. Serum lipids, liver function indexes by biochemical analyzers, and changes in liver pathology with hematoxylin-eosin (HE) and masson staining were detected. Furthermore, the serum adiponectin by enzyme-linked immunosorbent assay (ELISA) and liver adiponectin methylation levels in the promoter regions by pyrophosphate sequencing were determined. High throughput Illumina sequencing targeted microbial 16S genes, bioinformatics and statistical analysis identified cecal-associated gut microbiota. Results: HFD with antibiotic exposure showed the most severe steatohepatitis and a severe gut microbiota alteration. Reduced bacterial diversity was also seen and the abundances of Firmicutes, Lactobacillus, Cyanobacteria, Acidobacteria, Chlamydiae, Chlamydiales, Rubrobacteria, Verrucomicrobia, Blautia, Shewanella, Bacteroides, Bacteroides acidifaciens, and Bacteroides uniformis, were shown to be partly reversed by probiotic treatment. Decreased serum adiponectin levels and increased DNA methylation levels of adiponectin promoter regions were also markedly associated with the NAFLD progression during gut microbiota alteration. Conclusion: Our results suggested that both gut microbiota alteration and adiponectin variability may be drivers of NAFLD progression and that targeting the gut microbiota, such as via administration of a probiotic, may delay NAFLD progression via adiponectin