| 1. |
- Ma, Tao, et al.
(författare)
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Genomic insights into salt adaptation in a desert poplar
- 2013
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 4, s. 2797-
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Tidskriftsartikel (refereegranskat)abstract
- Despite the high economic and ecological importance of forests, our knowledge of the genomic evolution of trees under salt stress remains very limited. Here we report the genome sequence of the desert poplar, Populus euphratica, which exhibits high tolerance to salt stress. Its genome is very similar and collinear to that of the closely related mesophytic congener, P. trichocarpa. However, we find that several gene families likely to be involved in tolerance to salt stress contain significantly more gene copies within the P. euphratica lineage. Furthermore, genes showing evidence of positive selection are significantly enriched in functional categories related to salt stress. Some of these genes, and others within the same categories, are significantly upregulated under salt stress relative to their expression in another salt-sensitive poplar. Our results provide an important background for understanding tree adaptation to salt stress and facilitating the genetic improvement of cultivated poplars for saline soils.
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| 2. |
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| 3. |
- Yang, Ruiqi, et al.
(författare)
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Genomic insights revealed the environmental adaptability of Planococcus halotolerans Y50 isolated from petroleum-contaminated soil on the Qinghai-Tibet Plateau
- 2022
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Ingår i: Gene. - : Elsevier BV. - 0378-1119 .- 1879-0038. ; 823, s. 146368-
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Tidskriftsartikel (refereegranskat)abstract
- The Tibetan Plateau niche provides unprecedented opportunities to find microbes that are functional and commercial significance. The present study investigated the physiological and genomic characteristics of Pla-nococcus halotolerans Y50 that was isolated from a petroleum-contaminated soil sample from the Qinghai-Tibet Plateau, and it displayed psychrotolerant, antiradiation, and oil-degraded characteristics. Whole genome sequencing indicated that strain Y50 has a 3.52 Mb genome and 44.7% G + C content, and it possesses 3377 CDSs. The presence of a wide range of UV damage repair genes uvrX and uvsE, DNA repair genes radA and recN, superoxide dismutase, peroxiredoxin and dioxygenase genes provided the genomic basis for the adaptation of the plateau environment polluted by petroleum. Related experiments also verified that the Y50 strain could degrade n-alkanes from C-11-C-23, and approximately 30% of the total petroleum at 25 & DEG;C within 7 days. Meanwhile, strain Y50 could withstand 5 x 10(3) J/m(2) UVC and 10 KGy gamma ray radiation, and it had strong antioxidant and high radical scavengers for superoxide anion, hydroxyl radical and DPPH. In addition, pan-genome analysis and horizontal gene transfers revealed that strains with different niches have obtained various genes through hori -zontal gene transfer in the process of evolution, and the more similar their geographical locations, the more similar their members are genetically and ecologically. In conclusion, P. halotolerans Y50 possesses high potential of applications in the bioremediation of alpine hydrocarbons contaminated environment.
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| 4. |
- Chen, Xiangrong, 1982, et al.
(författare)
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AC and DC Pre-stressed Electrical Trees in LDPE and its Aluminum Oxide Nanocomposites
- 2016
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Ingår i: IEEE Transactions on Dielectrics and Electrical Insulation. - : Institute of Electrical and Electronics Engineers (IEEE). - 1558-4135 .- 1070-9878. ; 23:3, s. 1506-1514
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Tidskriftsartikel (refereegranskat)abstract
- Resistance of pure low density polyethylene (LDPE) and its aluminum oxide nanocomposites (up to 3.0 wt%) to degradation by electrical treeing under AC stress and DC pre-stress is analyzed. The experiments were carried out on wire-plane electrode specimens before and after exposure to thermal and DC electro-thermal ageing at 80 °C. The obtained results showed enhanced resistance of the nanocomposites to electrical tree inception under AC stress and the tree inception voltage (TIV) increased with nanoparticles content. It has been shown that there was an improved partial discharge (PD) resistance in the nanocomposites compared to the unfilled LDPE. The results also showed that the AC TIV in the nanocomposites consistently increased with the ageing and especially the DC electro-thermally aged specimens had about 30% higher the AC TIV as compared to the unaged material. This effect is attributed to significantly reduced mobility of charge carriers in the nanocomposites. The DC pre-stressed electrical trees generated in the investigated materials were of filamentary-branch structure and the branch channels content increases with the addition of nanoparticles. The mean tree number of the DC pre-stressed electrical trees decreased in the LDPE and its nanocomposites while the mean maximum tree length increased with the ageing treatments. It is postulated that material recrystallization and a very high electric field level on the wire electrode during the DC pre-stressed electrical tree test are the main reasons for the observed effects.
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| 5. |
- Fan, Dongming, et al.
(författare)
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Restoration of smart grids : Current status, challenges, and opportunities
- 2021
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Ingår i: Renewable & sustainable energy reviews. - : Elsevier. - 1364-0321 .- 1879-0690. ; 143
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Forskningsöversikt (refereegranskat)abstract
- Smart grids, which constitute intelligent infrastructure in smart cities, provide reliable, energy-efficient, and high-quality power to improve the standard of living while maintaining a sustainable environment. For self-healing, restoration is considered an effective and intelligent way to ensure that parts of the system remain active and even reconfigure automatically with external failures or attacks. Restoration has recently received considerable attention from researchers and engineers. Regarding the technical route of restoration, this survey reveals some common properties and identifies the research gaps in modeling frameworks, reconfiguration technologies, and optimization approaches. It presents a summary of the challenges and opportunities in restoration of smart grids. It is expected to facilitate the researchers in the advancement of effective and intelligent restoration of smart grids.
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| 6. |
- Fan, Dongming, et al.
(författare)
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Robustness of maintenance support service networks : attributes, evaluation and improvement
- 2021
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Ingår i: Reliability Engineering & System Safety. - : Elsevier. - 0951-8320 .- 1879-0836. ; 210
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Tidskriftsartikel (refereegranskat)abstract
- Maintenance support service network (MSSN) is used to provide maintenance services and maintain the operational status of equipment. However, the performance of MSSN has been significantly influenced by inevitable disturbance, which makes it vital to maintain its robustness. Existing research on robustness of MSSN mainly focuses on single-layer rather than two-layer network, which imposes constraints on the disturbances and limits its application. To solve these issues, this study develops a two-layer MSSN, consisting of a directed entity-layer and an undirected cyber-layer focusing on supporting maintenance service. A definition of robustness for two-layer MSSN is proposed, and effect propagation models are established to evaluate its robustness of MSSN, followed by its improvement strategies. In particular, two strategies applied in the single-layer MSSN are modified to adapt to the two-layer MSSN, and a novel greedy partnership building approach is proposed to find an optimal strategy under cascading failure, to maintain the robustness of MSSN from a complex network perspective. Finally, numerical examples are presented to illustrate the effectiveness of the proposed approach.
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| 7. |
- Gubanski, Stanislaw, 1950, et al.
(författare)
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Polymer composition and electrical devices
- 2021
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Patent (övrigt vetenskapligt/konstnärligt)abstract
- The invention relates to a polymer composition comprising a polymer (a) and a nanoparticle filler (b), wherein the polymer composition comprises a volume percentage (vol. %) of the nanoparticle filler (b), which is Dvol vol. %, and has a center-to-center average distance, in nanometer (nm), in two dimensions (2D) and with a free radius, from one nanoparticle to its nearest nanoparticle neighbour, which is R1st nm, and wherein the polymer composition shows a dependency between said center-to-center average distance to nearest neighbour, R1st, and said volume percentage, Dvol vol. %, which is R1st=E/(Dvol+0.3)+F, wherein Dvol1≤Dvol≤Dvol2, E1≤E≤E2, F1≤F≤F2, and Dvol1 is 0.010 and Dvol2 is 4.4, E1 is 100 and E2 is 280, and F1 is 50 and F2 is 140; an electrical device, e.g. a power cable; and a process for producing an electrical device.
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| 8. |
- Hoang, Tuan Anh, 1985, et al.
(författare)
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Charge Transport in LDPE Nanocomposites Part I—Experimental Approach
- 2016
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Ingår i: Polymers. - : MDPI AG. - 2073-4360. ; 8:3, s. 87:1-87:19
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Tidskriftsartikel (refereegranskat)abstract
- This work presents results of bulk conductivity and surface potential decay measurements on low-density polyethylene and its nanocomposites filled with uncoated MgO and Al2O3, with the aim to highlight the effect of the nanofillers on charge transport processes. Material samples at various filler contents, up to 9 wt %, were prepared in the form of thin films. The performed measurements show a significant impact of the nanofillers on reduction of material’s direct current (dc) conductivity. The investigations thus focused on the nanocomposites having the lowest dc conductivity. Various mechanisms of charge generation and transport in solids, including space charge limited current, Poole-Frenkel effect and Schottky injection, were utilized for examining the experimental results. The mobilities of charge carriers were deduced from the measured surface potential decay characteristics and were found to be at least two times lower for the nanocomposites. The temperature dependencies of the mobilities were compared for different materials.
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| 9. |
- Hoang, Tuan Anh, 1985, et al.
(författare)
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DC electrical conductivity of LDPE-based nanocomposites
- 2015
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Ingår i: 9th International Conference on Insulated Power Cables, Jicable’15, 21 – 25 June 2015, Versailles – France (2015). ; , s. paper B6.5-
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Konferensbidrag (refereegranskat)abstract
- This work presents studies of the effect of nanofillers on dc electrical conductivity of polymeric materials, potentially applicable in high voltage direct current (HVDC) cable insulation. Samples of low-density polyethylene (LDPE) filled with nanoparticles of aluminium oxide (Al2O3) and magnesium oxide (MgO) up to 3 wt% were prepared, on which charging currents were measured at 40 and 60 °C and electric stress of 32 kV/mm. Experimental results for nanocomposites were compared with those of reference LDPE. It was found that the addition of nanofillers led to a significant decrease in electrical volume conductivity and the decline depended strongly on filler type, its content and surface treatment. Further, the influence of specimen thickness on the conductivity was examined for verifying the operating conduction mechanisms. An indication was found that the space charge limited current (SCLC) mechanism dominated the conduction process in the reference material, while this effect ceased for the nanocomposites.
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| 10. |
- Kang, J., et al.
(författare)
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Investigation on the Tensile Behavior and Morphology Evolution of Isotactic Polypropylene Films Polymerized with Different Ziegler-Natta Catalysts
- 2015
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Ingår i: Advances in Polymer Technology. - : Wiley. - 0730-6679 .- 1098-2329.
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Tidskriftsartikel (refereegranskat)abstract
- Stereodefect distribution is very important in determining the morphology and properties of isotactic polypropylene (iPP). In this study, two iPPs (PP-A and PP-B) with different uniformities of stereodefect distribution were prepared. The tensile behavior and morphology evolution of their cast films were studied. The morphology study of the cast films showed that compared with PP-B, PP-A with less uniform distribution of stereodefects has smaller spherulites and spheruilitic boundaries and higher degree of crystallinity. In uniaxial tensile measurements, PP-A exhibited higher yield strength and lower elongation at break. When strain was 500%, PP-A exhibits totally transparent appearance and highly oriented structures without cavities, whereas PP-B shows opaque appearance and mass of both nanometer- and micrometer-sized cavities. Moreover, calculation of rigid amorphous fraction (RAF) indicated that PP-B cast film has a higher amount of RAF, which might be the reason for the different morphology evolutions and tensile behaviors of the samples.
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