| 1. |
- Gao, Guangbin, et al.
(författare)
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Understanding filamentous cyanobacteria and their adaptive niches in Lake Honghu, a shallow eutrophic lake
- 2025
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Ingår i: Journal of Environmental Sciences (China). - 1001-0742. ; 152, s. 219-234
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Tidskriftsartikel (refereegranskat)abstract
- Freshwater lakes globally are witnessing an escalation in the frequency and intensity of cyanobacterial harmful blooms. However, underlying factors influencing the succession or coexistence of cyanobacteria, especially filamentous ones, remain poorly understood. Lake Honghu, a Ramsar Wetland of International Importance with degrading aquatic ecological quality, served as a case study to elucidate the intricate relationship between environmental changes and cyanobacterial dynamics. Our analysis revealed a significant increase in the dominance of filamentous cyanobacteria, marked by high spatiotemporal variability in community structure. This dominance of filamentous diazotrophic cyanobacteria is attributed to a decrease in the ratio of dissolved inorganic nitrogen to total phosphorus and their capacity to utilize organic phosphorus in phosphorus-deficient conditions. Species-specific density variations were linked to diverse environmental factors, with total nitrogen or total phosphorus concentration remaining as a crucial factor influencing dominant cyanobacterial density fluctuations. The dominance of low-temperature-tolerant Aphanizomenon and Pseudanabaena was evident in spring and winter, whereas Dolichospermum and Cylindrospermopsis, which prefer higher temperatures, thrived in summer and autumn. Additionally, non-algal turbidity and heterogeneity can potentially alter the competitive outcome among filamentous cyanobacteria or foster coexistence under conditions of elevated temperatures and nutrient limitation. This study predicts that filamentous cyanobacteria may spread and persist in lakes spanning a wide trophic range. Current findings enhance our comprehension of the dynamic responses exhibited by filamentous bloom-forming cyanobacteria in the face of environmental changes within shallow eutrophic lakes and provide valuable insights for lake managers involved in the remediation of degraded shallow lakes.
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| 2. |
- Fang, Mei, et al.
(författare)
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Design and tailoring of inks for inkjet patterning of metal oxides
- 2020
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Ingår i: Royal Society Open Science. - : The Royal Society. - 2054-5703. ; 7:4
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Tidskriftsartikel (refereegranskat)abstract
- Inkjet printing has become a promising, efficient, inexpensive, scalable technique for materials deposition, mask-less and digital patterning in many device applications. Meanwhile, the ink preparation remains a challenge especially for printing functional oxide materials. Based on the principles of inkjet printing (especially relevant for piezoelectric drop-on-demand inkjet printer) and the process of the conversion of liquid ink into solid thin films of oxide materials, we present two approaches to the design and tailoring of inks: (i) oxide particle suspensions (e.g. SiO2, TiO2, Fe3O4) and (ii) metal-acetates precursor solutions for directly printing oxide thin films (e.g. ZnO, MgO, ITO and so forth). The solution inks are stable and produce tunable oxide films with high density and smooth surface. For some of the inks containing multi-type acetates with possible phase separation even before calcinations, we have developed a chelating procedure in order to tailor the films into single-phase homogeneity. The work lays a foundation for inkjet printing of oxides films for functional applications in electronic, photonic and energy devices.
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| 3. |
- Fang, Mei, et al.
(författare)
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'In-situ' ink-jet printed Fe-doped MgO thin films with tunable ferromagnetism
- 2020
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Ingår i: Zhongguó wùli xuékan. - : Elsevier. - 0577-9073. ; 67, s. 398-404
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Tidskriftsartikel (refereegranskat)abstract
- Magnetism in wide band gap materials is of great interests for future spintronic device applications. We prepared MgO and Fe-doped MgO films 'in-situ' on substrates by inkjet printing, and investigated the ferromagnetism tuned by the doping of Fe, the annealing temperature and the film thickness. It is found that the Fe-doping improves the crystallinity of the films with lattice structure changed by annealing temperature. The saturation magnetization (M-s) of the films enhanced by similar to 5 times comparing with the pure MgO thin film of similar thickness (similar to 90 nm), because of both the long-range ordering of localized 3d electrons in Fe and the defects induced magnetism. The M-s at 5 K decreases with the film thickness, which is mainly attributed to the interface induced ferromagnetism. The Fe-doped MgO films with ferromagnetism in this work can be used in future spintronic devices.
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| 4. |
- Fang, Mei, et al.
(författare)
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Inkjet printing Ag-TiO2 thin films with suppressed photoluminescence
- 2019
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Ingår i: Semiconductor Science and Technology. - : IOP PUBLISHING LTD. - 0268-1242 .- 1361-6641. ; 34:10
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Tidskriftsartikel (refereegranskat)abstract
- With ultraviolet sensitive photochemistry and photoelectric properties, TiO2 is attractive for applications like photocatalysis, photovoltaic devices, and sunscreen products, among others. By coating Ag on TiO2 surface, the sensitivity can be extended to visible light, endowing enhanced properties with potential new applications. In this work we inkjet print Ag-TiO2 films from particle suspensions, and investigate the structure, morphology, Ag distribution and the photoluminescence of the films It is found that Ag nanoparticles form bridges among TiO2 particles during the post-annealing. These metallic bridges can transport the excited electrons and suppress the recombination of electrons and holes with the photoluminescence of the film reduced by more than half. The work provides an industrial applicable, low-cost, environment friendly route of preparing Ag-TiO2 films for attractive photochemistry and photoelectric device applications.
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| 5. |
- Li, Jie, et al.
(författare)
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Maximum number of subtrees in cacti and block graphs
- 2022
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Ingår i: Aequationes Mathematicae. - : Springer. - 0001-9054 .- 1420-8903. ; 96, s. 1027-1040
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Tidskriftsartikel (refereegranskat)abstract
- For a graph G, we denote by N(G) the number of non-empty subtrees of G. As a topological index based on counting, N(G) has some correlations to other well studied topological indices, including the Wiener index W(G). In this paper we characterize the extremal graphs with the maximum number of subtrees among all cacti of order n with k cycles. Similarly, the extremal graphs with the maximum number of subtrees among all block graphs of order n with k blocks are also determined and shown to have the minimum Wiener index within the same collection of graphs. Analogous results are also obtained for the number of connected subgraphs C(G). Finally, a general question is posed concerning the relation between the number of subtrees and the Wiener index of graphs.
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