| 1. |
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
- Wu, Lele, et al.
(författare)
-
Organic matter composition and stability in estuarine wetlands depending on soil salinity
- 2024
-
Ingår i: Science of the Total Environment. - 0048-9697 .- 1879-1026. ; 945
-
Tidskriftsartikel (refereegranskat)abstract
- Coastal wetlands are key players in mitigating global climate change by sequestering soil organic matter. Soil organic matter consists of less stable particulate organic matter (POM) and more stable mineral-associated organic matter (MAOM). The distribution and drivers of MAOM and POM in coastal wetlands have received little attention, despite the processes and mechanisms differ from that in the upland soils. We explored the distribution of POM and MAOM, their contributions to SOM, and the controlling factors along a salinity gradient in an estuarine wetland. In the estuarine wetland, POM C and N were influenced by soil depth and vegetation type, whereas MAOM C and N were influenced only by vegetation type. In the estuarine wetland, SOM was predominantly in the form of MAOM (> 70 %) and increased with salinity (70 %–76 %), leading to long-term C sequestration. Both POM and MAOM increased with SOM, and the increase rate of POM was higher than that of MAOM. Aboveground plant biomass decreased with increasing salinity, resulted in a decrease in POM C (46 %–81 %) and N (52 %–82 %) pools. As the mineral amount and activity, and microbial biomass decreased, the MAOM C (2.5 %–64 %) and N pool (8.6 %–59 %) decreased with salinity. When evaluating POM, the most influential factors were microbial biomass carbon (MBC) and dissolved organic carbon (DOC). Key parameters, including MBC, DOC, soil salinity, soil water content, aboveground plant biomass, mineral content and activity, and bulk density, were identified as influencing factors for both MAOM abundance. Soil water content not only directly controlled MAOM, but together with salinity also indirectly regulated POM and MAOM by controlling microbial biomass and aboveground plant biomass. Our findings have important implications for improving the accumulation and increased stability of soil organic matter in coastal wetlands, considering the global sea level rise and increased frequency of inundation.
|
|
| 5. |
- Wu, Yuntao, et al.
(författare)
-
Climatic controls on stable carbon and nitrogen isotope compositions of temperate grasslands in northern China
- 2023
-
Ingår i: Plant and Soil. - : Springer. - 0032-079X .- 1573-5036. ; 491, s. 133-144
-
Tidskriftsartikel (refereegranskat)abstract
- Aims The natural abundances of stable carbon (C) and nitrogen (N) isotopes (delta C-13 and delta N-15) are extensively used to indicate the C and N biogeochemical cycles at large spatial scales. However, the spatial patterns of delta C-13 and delta N-15 in plant-soil systems of grasslands in northern China and their main driving factors across regional climatic gradient are still not well understood. Methods We measured plant and soil delta C-13 and delta N-15 compositions as well as their associated environmental factors across 2000 km climatic gradient (-0.2 to 9 degrees C; 152 to 502 mm) in grasslands of northern China. Results The soil delta C-13 and delta N-15 values in surface were lower than those in bottom for temperate typical steppe but had no significant differences for temperate meadow steppe and temperate desert steppe. Soil delta C-13 values declined with increasing soil organic carbon (SOC) but increased as mean annual temperature (MAT). These changes were attributed to the microbial decomposition rate. The delta N-15 values in soil and plant were negatively correlated with MAT and mean annual precipitation (MAP), which were mainly related to the low soil organic matter mineralization rate and the shift of dominant species from C-4 to C-3. Conclusions Our results indicate the spatial patterns and different influencing factors on delta C-13 and delta N-15 values along the climatic gradient in grasslands of northern China. The findings will provide scientific references for future research on the C and N biogeochemical cycles of temperate grasslands.
|
|
| 6. |
- Wu, Yuntao, et al.
(författare)
-
Silicon promotes biomass accumulation in Phragmites australis under waterlogged conditions in coastal wetland
- 2024
-
Ingår i: Plant and Soil. - : Springer Nature. - 0032-079X .- 1573-5036.
-
Tidskriftsartikel (refereegranskat)abstract
- Aims Previous studies have shown that silicon (Si) can affect plant growth and yield by regulating the availability of other nutrients. However, the mechanisms by which Si affects plant biomass accumulation in coastal wetlands are not well explored. Methods We conducted a sampling campaign across the whole growing season of Phragmites australis under waterlogging and drought conditions in coastal wetland, and quantified the effects of Si availability on biomass accumulation. Results Compared with drought condition, the waterlogged condition improved the utilization efficiency of nitrogen (N) and phosphorus (P) of P. australis regulated by higher Si contents. Meanwhile, the increased Si contents promoted the utilization of N and P in leaf, suggesting that the increase in Si contents optimizes the photosynthetic process. Lignin contents in P. australis decreased with the increasing Si contents, which confirmed that Si can replace structural carbon components. In addition, principal component analysis (PCA) showed aboveground biomass accumulation of P. australis was synchronized with Si accumulation, indicating that Si was a beneficial element to promote biomass accumulation. Conclusions Our study implies that increasing Si availability is conducive to biomass accumulation of P. australis in waterlogged wetlands, which will provide important scientific references for the management of coastal wetland ecosystem and the increase of global 'blue carbon' sequestration.
|
|
| 7. |
- Feng, Jun, et al.
(författare)
-
Giant Moisture Responsiveness of VS2 Ultrathin Nanosheets for Novel Touchless Positioning Interface
- 2012
-
Ingår i: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095. ; 24:15, s. 1969-1974
-
Tidskriftsartikel (refereegranskat)abstract
- Utilizing a thin film of VS2 ultrathin nanosheets with giant and fast moisture responsiveness, a brand-new model of moisture-based positioning interface is put forward here, by which not only the 2D position information of finger tips can be acquired, but also the relative height can be detected as the third dimensionality, representing a promising platform for advanced man-machine interactive systems.
|
|
| 8. |
- Li, Fusheng, et al.
(författare)
-
Dye-sensitized LaFeO3 photocathode for solar-driven H-2 generation
- 2019
-
Ingår i: Chemical Communications. - : Royal Society of Chemistry. - 1359-7345 .- 1364-548X. ; 55:86, s. 12940-12943
-
Tidskriftsartikel (refereegranskat)abstract
- Mesoporous LaFeO3 was used as a p-type visible-light-absorbing semiconductor (VLAS) substrate for light-driven H-2 generation. The successful modification of LaFeO3 with a molecular dye (P1*) and a molecular hydrogen production catalyst (NiP) paved a novel way to construct DS-PEC photocathodes for solar-driven H-2 generation by using VLASs.
|
|
| 9. |
- Lin, Chenwen, et al.
(författare)
-
Hydrogen-Incorporated TiS2 Ultrathin Nanosheets with Ultrahigh Conductivity for Stamp-Transferrable Electrodes
- 2013
-
Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 135:13, s. 5144-5151
-
Tidskriftsartikel (refereegranskat)abstract
- As a conceptually new class of two-dimensional (2D) materials, the ultrathin nanosheets as inorganic graphene analogues (IGAs) play an increasingly vital role in the new-generation electronics. However, the relatively low electrical conductivity of inorganic ultrathin nanosheets in current stage significantly hampered their conducting electrode applications in constructing nanodevices. We developed the unprecedentedly high electrical conductivity in inorganic ultrathin nanosheets. The hydric titanium disulfide (HTS) ultrathin nanosheets, as a new IGAs, exhibit the exclusively high electrical conductivity of 6.76 x 10(4) S/m at room temperature, which is superior to indium tin oxide (1.9 x 10(4) S/m), recording the best value in the solution assembled 2D thin films of both graphene (5.5 x 10(4) S/m) and inorganic graphene analogues (5.0 x 10(2) S/m). The modified hydrogen on S-Ti-S layers contributes additional electrons to the TiS2 layered frameworks, rendering the controllable electrical conductivity as well as the electron concentrations. Together with synergic advantages of the excellent mechanical flexibility, high stability, and stamp-transferrable properties, the HTS thin films show promising capability for being the next generation conducting electrode material in the nanodevice fields.
|
|
| 10. |
- Mu, Tong, et al.
(författare)
-
High-performance imidazole-containing polymers for applications in high temperature polymer electrolyte membrane fuel cells
- 2024
-
Ingår i: Journal of Energy Chemistry. - 2095-4956. ; 98, s. 512-523
-
Tidskriftsartikel (refereegranskat)abstract
- This work focuses on the development of high temperature polymer electrolyte membranes (HT-PEMs) as key materials for HT-PEM fuel cells (HT-PEMFCs). Recognizing the challenges associated with the phosphoric acid (PA) doped polybenzimidazole (PBI) membranes, including the use of carcinogenic monomers and complex synthesis procedures, this study aims to develop more cost-effective, readily synthesized and high-performance alternatives. A series of superacid-catalyzed polyhydroxyalkylation reactions have been meticulously designed between p-triphenyl and aldehydes bearing imidazole moieties, resulting in a new class of HT-PEMs. It is found that the chemical structure of aldehyde-substituted N-heterocycles significantly impacts the polymerization reaction. Specifically, the use of 1-methyl-2-imidazole-formaldehyde and 1H-imidazole-4-formaldehyde monomers leads to yield high-viscosity, rigid and ether-free polymers, denoted as PTIm-a and PTIm-b. Membranes fabricated from these polymers, due to their pendent imidazole groups, exhibit an exceptional capacity for PA absorption. Notably, PTIm-a, featuring methylimidazole moieties, demonstrates a superior chemical stability which maintains morphology and structural stability during 350 h of Fenton testing. After being immersed in 75 wt% PA at 40 °C, the PTIm-a membrane achieves a PA content of 152%, maintains a good tensile strength of 13.6 MPa, and exhibits a moderate conductivity of 50.2 mS cm-1 at 180 °C. Under H2/O2 operational conditions, a single cell based on the PTIm-a membrane attains a peak power density of 732 mW cm-2 at 180 °C without backpressure. Furthermore, the membrane demonstrates stable cycle stability over 173 h within 18 days period at a current density of 200 mA cm-2, indicating its potential for practical application in HT-PEMFCs. This work contributes innovative strategies for the synthesis of advanced HT-PEMs, offering significant improvements in membrane properties and fuel cell performance, thus expanding the horizons of HT-PEMFC technology.
|
|
| 11. |
- Wu, G. J., et al.
(författare)
-
Effects of Initial Shear Layer State on Screech in a RectangulaJet
- 2022
-
Ingår i: 28th AIAA/CEAS Aeroacoustics Conference, 2022. - Reston, Virginia : American Institute of Aeronautics and Astronautics (AIAA).
-
Konferensbidrag (refereegranskat)abstract
- High-fidelity large-eddy simulations are conducted for a 4:1 rectangular supersonic nozzle at under-expanded screeching conditions. By creating a small groove on the nozzle surface, we numerically modify the boundary layer inside the nozzle and the resulting jet initial shear layer. A total of 5 cases with different groove sizes are studied and compared with the no-groove baseline case. Near-field flow statistics and far-field acoustics are analyzed. The geometric tripping method is shown to increase the turbulent kinetic energy and boundary layer thickness at the nozzle exit. The slight modification in the initial shear layer state leads to different shear layer thicknesses and shock cell decay rates near the end of the jet potential core. Screech tone amplitude variation is observed, with largest difference measured to be 2.9 dB compared to the baseline value. The dominant coherent structures associated with screech generation are studied with spectral proper orthogonal decomposition. The amplitudes of the internal upstream-traveling wave and the downstream-traveling Kelvin-Helmholtz wave are calculated. The differences in the screech tone amplitude are found to be related to the strength of the Kelvin-Helmholtz wave, which is a result of the modified receptivity of the initial shear layer.
|
|
| 12. |
- Xu, Kun, et al.
(författare)
-
Highly entangled K0.5V2O5 superlong nanobelt membranes for flexible nonvolatile memory devices
- 2012
-
Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 22:35, s. 18214-18220
-
Tidskriftsartikel (refereegranskat)abstract
- Flexible electronics has been an intensively pursued hot topic in recent years, and flexible nonvolatile memory devices (NVMs) are also an important concept in modern electronics due to the advantages of retaining stored information even when not powered, with great portability and high deformability. In this study, we report that delta-K0.5V2O5 bronze with sandwiched potassium atoms in the V-O framework has been found to be a new promising material platform for intriguing nonvolatile memory applications. The bronze structure with the sandwiched alkali metal atoms between the two V2O5 layers ensures the promising NVM effect by changing the electronic properties under an applied electric field. The delta-K0.5V2O5 bronze entangled superlong nanobelt networks, which are established via the "solid-solution-solid" (SSS) mechanism and a hydrogen-bond-assisted entangling process, bring the synergic advantages of excellent mechanical and electrical properties. Spin polarized GGA+U density functional theory calculations elucidate well the nature of bronze-based NVM, in which the overall effect of applying an electric field is to reduce the energy gap, no matter what the direction of the electric field is; the effects of electric field and ion shift would follow the same trend, the non-linear band gap changes would lead to resistance changes of this material. The NVMs based on the entangled superlong nanobelt membrane possess the advantages of not only low cost and very simple device structure, but also a reversible and noticeable nonlinear hysteresis, low consumption, stable WRER cycles, and a long retention time over 1000 s, showing promise for next-generation flexible NVMs.
|
|
| 13. |
- Yang, Xiaomin, et al.
(författare)
-
Phytolith-rich straw application and groundwater table management over 36 years affect the soil-plant silicon cycle of a paddy field
- 2020
-
Ingår i: Plant and Soil. - : Springer. - 0032-079X .- 1573-5036. ; 454, s. 343-358
-
Tidskriftsartikel (refereegranskat)abstract
- Background and aims Silicon (Si) deficiency is a major constraint on rice production. The objective of this study was to evaluate the long-term influence of phytolith-rich straw return and groundwater table management on labile Si fractions in paddy soil and subsequent plant Si uptake. Methods A field experiment was conducted over 36 years in subtropical China with different application doses of phytolith-rich straw and a groundwater table of either 20 or 80 cm. An optimized sequential chemical extraction procedure allowed us to determine labile Si fractions, represented by CaCl2-Si, Acetic-Si, H2O2-Si, Oxalate-Si, and Na2CO3-Si. Additional analyses included the determination of amorphous silica particles in soil, phytoliths in supplied straw, Si in planted rice straw, and the dissolution rate of phytoliths extracted from supplied straw. Results Long-term application of phytolith-rich straw significantly increased the H2O2-Si and Na2CO3-Si contents. The CaCl2-Si (5.21-7.91 mg kg(- 1)), H2O2-Si (50.0-72.4 mg kg(- 1)) and Na2CO3-Si (3.33-4.60 g kg(- 1)) contents were positively correlated with soil organic carbon. The Si content (13.6-28.9 g kg(-& x200d;1)) in planted rice straw significantly (p < 0.05) increased with the application dose of phytolith-rich straw under both groundwater tables. This effect was significantly (p < 0.05) greater under 80 cm groundwater table than under 20 cm groundwater table for matching straw amendments. Conclusions This study indicates that long-term application of phytolith-rich straw and groundwater management significantly increase soil Si bioavailability by promoting accumulation of organic matter and phytoliths, and enhancing the soil-plant Si cycle.
|
|
