20 research outputs found
China’s 10-year progress in DC gas-insulated equipment: From basic research to industry perspective
The construction of the future energy structure of China under the 2050 carbon-neutral vision requires compact direct current (DC) gas-insulation equipment as important nodes and solutions to support electric power transmission and distribution of long-distance and large-capacity. This paper reviews China's 10-year progress in DC gas-insulated equipment. Important progresses in basic research and industry perspective are presented, with related scientific issues and technical bottlenecks being discussed. The progress in DC gas-insulated equipment worldwide (Europe, Japan, America) is also reported briefly
The Ninth Visual Object Tracking VOT2021 Challenge Results
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Effect of Sodium Borate on the Preparation of TiN from Titanomagnetite Concentrates by Carbothermic Reduction–Magnetic Separation and Acid Leaching Process
Carbothermic reduction–magnetic separation and acid leaching processes were used to produce TiN and direct reduced iron (DRI) from titanomagnetite concentrates. The effects of sodium borate on the reduction behavior of TMCs, the magnetic separation of the reduced products, and the purification of the impure TiN by acid leaching were investigated. Results of x-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy analysis showed that magnesium aluminate spinel (MgAl2O4) was generated in the reduced products, which could hinder the purification of the TiN. Adding sodium borate not only inhibited the formation of MgAl2O4, but also promoted the formation of TiN by decreasing the roasting temperature and time. Adding sodium borate slightly affected the separation of metallic Fe and TiN. By adding 16% sodium borate, a DRI with 94.3% Fe, 0.6% Ti, and 0.1% V was obtained by magnetic separation. After HCl + HF leaching, the TiN product containing 74.1% Ti and 2.8% V was obtained with the Ti recovery of 94.6% and V recovery of 58.3%
Difference in Accumulation of Five Phthalate Esters in Different Elite Tea Cultivars and Their Correlation with Environment Factors
Plasticizers, i.e., phthalate esters (PAEs) were liable to be detected from fresh tea leaves and tea products. In order to monitor the pollution of PAEs in tea plants and compare the difference among PAEs content of tea cultivars, fifteen elite cultivars in tea plant cultivar gardens were chosen. PAEs were extracted from the upper mature leaves and lower mature leaves of tea bushes and determined via GC–MS once every two months, six times in total in one anniversary. DMP, DEP, DiBP, DBP, and DEHP were detected in fifteen tea cultivars. DBP was the predominant congener in fifteen tea cultivars, which was followed by DiBP. PAEs content in upper mature leaves was significantly lower than that in lower mature leaves in all months. There was no significant difference among PAEs content from the fifteen tea cultivars. Except for summer, the PAEs content of fresh tea leaves gradually increased from spring to winter. The correlation analysis result was that PAEs had significant negative correlation with air temperature and positive correlation with air quality index (p p < 0.05). According to cluster analysis, three types of fresh tea leaves with high, medium, and low accumulation accounted for 26.7%, 20%, and 53.3%, respectively. The results could supply a reference for monitoring of pollution of PAEs in fresh tea leaves, as well as an evaluation of PAEs content difference of tea plant cultivars
Engineering of Bacteriophage T4 Genome Using CRISPR-Cas9
Bacteriophages likely constitute
the largest biomass on Earth.
However, very few phage genomes have been well-characterized, the
tailed phage T4 genome being one of them. Even in T4, much of the
genome remained uncharacterized. The classical genetic strategies
are tedious, compounded by genome modifications such as cytosine hydroxylmethylation
and glucosylation which makes T4 DNA resistant to most restriction
endonucleases. Here, using the type-II CRISPR-Cas9 system, we report
the editing of both modified (ghm-Cytosine) and unmodified (Cytosine)
T4 genomes. The modified genome, however, is less susceptible to Cas9
nuclease attack when compared to the unmodified genome. The efficiency
of restriction of modified phage infection varied greatly in a spacer-dependent
manner, which explains some of the previous contradictory results.
We developed a genome editing strategy by codelivering into <i>E. coli</i> a CRISPR-Cas9 plasmid and a donor plasmid containing
the desired mutation(s). Single and multiple point mutations, insertions
and deletions were introduced into both modified and unmodified genomes.
As short as 50-bp homologous flanking arms were sufficient to generate
recombinants that can be selected under the pressure of CRISPR-Cas9
nuclease. A 294-bp deletion in RNA ligase gene <i>rnlB</i> produced viable plaques, demonstrating the usefulness of this editing
strategy to determine the essentiality of a given gene. These results
provide the first demonstration of phage T4 genome editing that might
be extended to other phage genomes in nature to create useful recombinants
for phage therapy applications