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When the space high-energy electron storm is generated in the Space Solar Power Station, the high voltage biased on the dielectric materials is a key factor affecting the deep charging process. In this work, the electron transport process in poly-ether-ether-ketone flat plates has been studied by the Geant4 simulation. It is found that the trapped charge density enhances 2-3 orders of magnitude under high-energy electron storms and that the trapped charge density gradually increases with the increase of the radiation time. The number of electrons deposited and charge migration decreases as the shielding thickness increases, while the trapped charge density decreases significantly and its spatial distribution gradually changes to a concave distribution. [ABSTRACT FROM AUTHOR]

In order to solve the problem that it is difficult to grow diamond films with high binding force on the surface of high cobalt cemented carbide, the Cr/CrSiN film was used as the transition layer, and the nanocrystalline diamond films (NCD), the submicrocrystalline diamond films (SMCD) and the microcrystalline diamond films (MCD) were deposited on the cemented carbide by hot filament chemical vapor deposition method, and their binding forces were studied. The results show that the Cr/CrSiN transition layer can be used to deposit diamond films with excellent bonding strength on the surface of high cobalt cemented carbide. NCD has the best binding force, followed by SMCD, and MCD has the worst binding force. When the grain size of the diamond film increases, the bonding forces of the diamond film weaken due to the poor toughness of the diamond films and severe carbonization of the transition layer. When the crystal size of the diamond film increases, the binding force of the diamond film becomes weak due to the poor toughness of the diamond film and serious carbonization of the transition layer. [ABSTRACT FROM AUTHOR]

As the increase of demand for seafood supplies, a large amount of high-protein feed has been added to mariculture aeras, which causes hazards for the cultured organisms and environment. Here, we used 16S rRNA gene high-throughput sequencing to evaluate the bacterial communities in the sediments of two aquaculture systems (fish and oyster culture) in Xiangshan Bay, China for four seasons. Analysis of variance results showed that the abundance and biodiversity differed significantly between the culture areas and control areas, and different seasons as well. Proteobacteria, Planctomycetes, and Bacteroidetes were the three most abundant phyla. Gammaproteobacteria, Deltaproteobacteria, and Bacteroidia were the three most abundant classes. Principal co-ordinates analysis showed that sediment bacterial community composition in the fish and oyster culture areas significantly differed from that in the control areas. Analysis of the function prediction of pathways related to the nitrogen cycle in sediments revealed a higher proportion of genes involved in denitrification in aquaculture farms. Nitrate respiration particularly occurred in fish areas, whereas nitrate reduction occurred both in fish and oyster areas, and the proportions in winter were significantly higher than that in other seasons. It also provides insights into the indirect effects of human aquaculture activities on coastal algal blooms. [ABSTRACT FROM AUTHOR]

Flower-like and pompon-like titanium dioxide (TiO2) anode materials are of interest due to various characteristics such as the excellent transport kinetics of lithium ions, favorable safety performance, low volume expansion coefficient, and special shapes. The TiO2 anode materials in flower-like or pompon-like shapes were prepared by applying the normal-pressure hydrolysis-ion exchange of potassium (K) salt. Furthermore, the influences of different calcination temperatures on the phase structure, shape, and electrochemical performance of the materials were investigated. The results show that TiO2 prepared by applying the aforementioned technique within the test temperature range appears in anatase form. Moreover, TiO2 crystals vary from flower-like to pompon-like materials with increasing calcination temperature. The materials show optimal electrochemical performance at a calcination temperature of 700 °C: the specific charge/discharge capacity in the first cycle reaches 250.2 mAh·g−1 at a current density of 20 mA·g−1 and a capacity of 185.3 mAh·g−1 after 20 cycles at a current density of 100 mA·g−1, retaining 85.8% of the original capacity. [ABSTRACT FROM AUTHOR]

In this paper, we report a facile one-step hydrothermal method to synthesize tetragonal Na 3 V 2 (PO 4 ) 2 F 3 @C particles which are connected by carbon nanotubes (CNTs) networks, using water as hydrothermal solvents. In this strategy, the reduction and crystallization of materials are carried out in the hydrothermal process (180°C, 12 h), no additional heat treatment is required. The well-crystallized Na 3 V 2 (PO 4 ) 2 F 3 tetragonal grains (5-10 μm) are coated with amorphous nano-carbon and connected by highly conductive CNTs. The addition of CNTs can not only improve the conductivity of materials but also effectively inhibit the Na 3 V 2 (PO 4 ) 2 F 3 grains over growth. The Na 3 V 2 (PO 4 ) 2 F 3 @C/CNTs composite possesses very flat charge/discharge platforms of 3.6 and 4.1 V. The sample exhibits an initial discharge specific capacity of 120.2 and 74.3 mAh g -1 at 0.1 and 10 C rate, respectively, and shows excellent cyclical stability. The composite owns excellent electrochemical performances owing to the three-dimensional highly conductive network which is co-constructed by the CNTs and nano-carbon coating layer., (Copyright © 2019 Guo, Hu, Zhang, Zhang, Hou, Sui and Wu.)