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[Display omitted] • Water release from local reservoirs significantly raised the lake level in dry season. • Release of local reservoirs decreased the duration and severity/intensity of drought. • Exposure duration of wetland was shortened and the area with long duration decreased. • Joint operation of local reservoirs and the TGR has further alleviated the droughts. Lake is an important component of the Earth's surface water bodies. Frequent and serious drought events in lakes have affected the security of regional water resources and caused the degradation of the lake ecosystem. Poyang Lake, the largest freshwater lake in China, has been suffering from increasingly severe hydrological droughts. This study simulated and investigated the effects of water release from local reservoirs in dry season on hydrological droughts in Poyang Lake based on a hydrodynamic model MIKE 21, and quantified the effectiveness of the joint operation of local reservoirs and the Three Gorges Reservoir (TGR). Major results showed that the water level of Poyang Lake during the dry period was significantly raised by the water release from local reservoirs, especially in the northern lake area. The average and the lowest lake level increased from 10.99 m to 11.18–11.59 m and from 9.97 m to 10.14–10.50 m at Xingzi station, respectively. Meanwhile, both the duration of low water and the drought severity/intensity (DS/DI) decreased significantly, with the duration decreasing from 128 days to 105–115 days for typical threshold lake level of 12.0 m, and the DS and DI decreasing from 176.6 m and 1.38 m/day to 117.6–155.3 m and 1.12–1.35 m/day, respectively. Moreover, the release of local reservoirs shortened the exposure duration of beach wetland, from nearly 3 months to about 1.5–2.5 months at the northern channel of Poyang Lake. The area with long exposure duration (>120 days) was also significantly reduced. In addition, the hydrodynamic simulations revealed that the joint operation of local reservoirs and the TGR further raised the average and the lowest lake level and decreased the duration of low water and drought severity and intensity. Outcomes of the study provided valuable references for mitigating lake droughts in complex river-lake-catchment system. [ABSTRACT FROM AUTHOR]

• Projected runoff will increase during 2020–2099, and peak flow will be delayed from June to July. • The range of time distribution will become wide for DTFEs, while narrow for FTDEs in the future. • Projected DFAAEs are mainly mild, and the moderate and extreme DFAAEs will be reduced. • The intensity of Projected DFAAE will be stronger in the future. Drought-flood abrupt alternation events (DFAAEs) bring about detrimental impacts on economics and environment. Projection of the future change in the DFAAEs is a challenging issue. Incorporated with the datasets of the Coupled Model Intercomparison Project Phase 5 under two Representative Concentration Pathway scenarios (RCP4.5 and RCP8.5), we applied the Soil and Water Assessment Tool model and the drought-flood abrupt alternation index (DFAAI) to detect climate change impacts on the DFAAEs in the Poyang Lake Basin for the period from 2020 to 2099. Our results demonstrated that the projected DFAAEs would become more frequent and be mainly distributed from January to October. Among them, the drought-to-flood events mainly occur from January to July, while the flood-to-drought events mainly occur from July to October. The occurrence of the DFAAEs is more frequent, and the occurrence frequency of DFAAEs under RCP4.5 is 75. The mild DFAAEs would be the dominated events in the Poyang Lake Basin, while the moderate and extreme DFAAEs are spatially unevenly distributed. The annual maximum and minimum of DFAAI would increase, and the frequency and intensity of the DFAAEs tend to increase. The projected runoff tends to increase but spatially homogenous. The projected peak flow would delay leading to a change in the transition time of the DFAAEs' type. This study provides a future projection on DFAAEs, valuable for policy makers to mitigate flood disasters at a basin scale. [ABSTRACT FROM AUTHOR]

Non-stoichiometric hydrogenated amorphous silicon carbide thin films (α-SiC:H) were deposited by plasma-enhanced chemical vapor deposition. The samples were subsequently post-annealed at 750, 900, 1050, and 1200 °C, respectively. Photoluminescence (PL) was measured by fluorescence spectrometer at room temperature. Infrared absorption was carried out by Fourier transform infrared absorption. Chemical compositions were analyzed by X-ray photoelectron spectroscopy. The synthesis of silicon quantum dots (Si-QDs) was characterized by Raman scattering spectroscopy and directly by high-resolution transmission electron microscope. PL measurements revealed that there were complicatedly shifted sub-bands upon the thermal annealing temperature increase. The behaviors of these shifted sub-bands showed converse trends as that of the local Si C bonding densities. A possible influence for the PL by the evolvement of the local Si C bonding densities and the synthesis of Si-QDs in the α-SiC:H samples is supposed. [ABSTRACT FROM AUTHOR]

Based on the analysis of the physical thermal model for a microbolometer under pulse bias, a new temperature compensation method for microbolometric focal plane array is proposed to compensate the substrate temperature fluctuation in microbolometric array. The self-heating and infrared responding voltage expressions of the microbolometer under pulse current bias are derived from the heat balance equation of the physical thermal model for the microbolometer, and these two expressions indicate that the microbolometer self-heating and infrared voltage responsivity expressions are dependent on the substrate temperature of the microbolometer with some other constant characteristic parameters. Through the obtained expressions, different pulse bias currents are provided to the microbolometer and its corresponding blind element at different substrate temperatures to get the same voltage responsivity of the microbolometer at different ambient temperatures. The proposed temperature compensation method can be utilized for a microbolometric focal plane array with low-power consumption and high temperature-resolution. [ABSTRACT FROM AUTHOR]

Hydrogenated amorphous silicon carbide thin films (a-SiC:H) were prepared by plasma-enhanced chemical vapor deposition (PECVD) and thermal annealed at temperatures of 900, 1050, and 1200 °C, respectively. The influence of annealing temperature on the silicon quantum dot (QD) synthesis was investigated by Raman scattering spectroscopy, X-ray diffraction spectroscopy, and high-resolution transmission electron microscopy. The influence of annealing temperature on the chemical bonding configurations was revealed by Fourier transform infrared absorption microscopy. The element ratios of the as-deposited sample were deduced by X-ray photoelectron spectroscopy. Results reveal that the samples are in silicon-rich nature. Silicon in the as-deposited sample and the 900 °C annealed sample are amorphous. When the annealing temperature is increased to 1050 °C, crystal silicon QDs have come into being. The calculated number density is about 2.15 ± 0.03 × 10 12 cm − 2 and more than 80 ± 3% of the silicon QDs fall within a narrow size range of 2–3 nm. When the annealing temperature is increased to 1200 °C, the average size of crystal silicon QDs is tuned from 2.6 to 3.2 nm, while the crystallinity is enhanced from 56.7 ± 2.5 to 67.1 ± 1.5%. We attribute the influence of annealing temperature on the synthesis of silicon QDs to be dependent on the evolution of chemical bonding configurations and the agglomeration of silicon atoms from the host matrix. [ABSTRACT FROM AUTHOR]

• High spatial–temporal resolution of drought monitoring dataset was constructed. • Composite index of anthropogenic influence was constructed using multi-source data. • Human contribution to drought increases exponentially with social development level. • Effects of human activities on drought can be spatially opposite. Drought has serious impacts on agricultural production and ecological environment in China. Study on the causes of drought and drought monitoring technology is crucial for drought mitigation. This study conducts drought monitoring based on temperature vegetation dryness index (TVDI) and investigates with the impact of anthropogenic pressure in the Poyang Lake basin (PYLB). In the study, the MODIS normalized vegetation index (NDVI) and land surface temperature (LST) products from 2000 to 2021 were selected to construct NDVI-LST feature space processed with elevation correction, from which the monthly TVDI data was calculated. The land use data and nighttime light data were used to construct the anthropogenic pressure index (API). The results indicate that the frequency of drought in the PYLB is higher in the south and lower in the north. According to drought influence scope (DIS), the occurrence frequency of basin-wide drought (DIS ≥ 50%) in the PYLB is the highest, followed by regional drought (33%≤DIS < 50%), partial local drought (25%≤DIS < 33%), and local drought (10%≤DIS < 25%). The basin as a whole showed an obvious wetting trend in spring and a drying trend in autumn. During the study period, API in the north of PYLB was obviously higher than that in the south, and showed a general increasing trend. The contribution of human activities to drought in the PYLB increased exponentially with the improvement of social development level. Meanwhile, the impact of human activities on drought shows spatial differentiation. Ecological protection and green development have been implemented in the northerly region of the PYLB, and anthropogenic pressure inhibited the degree of drought. Oppositely, extensive socioeconomic development in the central and southern parts of the PYLB has caused damage to the environment and indirectly aggravated regional drought. This study makes important contributions to exploring the response between remote sensing drought monitoring and anthropogenic pressure and promoting regional drought mitigation in humid areas. [ABSTRACT FROM AUTHOR]

Hydrological extremes are changing under the impacts of environmental change, i.e., climate variation and human activity, which can substantially influence ecosystems and the living environment of humans in affected region. This study investigates the impacts of environmental change on hydrological drought in the middle reaches of the Yangtze River in China based on hydrological modelling. Change points for streamflow into two major lakes and a reservoir in the study area were detected in the late 1980s using the Mann-Kendall test. Streamflow simulation by a water balance model was performed, and the resulting Kling-Gupta efficiency value was >0.90. Hydrological drought events were identified based on the simulated streamflow under different scenarios. The results show that the hydrological drought occurrence was increased by precipitation, whereas the drought peak value was increased by potential evapotranspiration. The impacts of precipitation and potential evapotranspiration on drought severity and duration varied in the study area. However, hydrological drought was intensified by the influence of human activity, which increased the severity, duration and peak value of droughts. The dominant factor for hydrological drought severity is precipitation, followed by potential evapotranspiration and human activity. The impacts of climate variation and human activity on drought severity are larger than on drought duration. In addition, environmental change is shown to have an “accumulation effect” on hydrological drought, demonstrating that the indirect impacts of environmental change on hydrological drought are much larger than the direct impacts on streamflow. This study improves our understanding of the responses of hydrological extremes to environmental change, which is useful for the management of water resources and the prediction of hydrological disasters. [ABSTRACT FROM AUTHOR]

Investigation of concurrent hydrological drought events is helpful for understanding the inherent mechanism of hydrological extremes and designing corresponding adaptation strategy. This study investigates concurrent hydrological drought in the Poyang lake-catchment-river system from 1960 to 2013 based on copula functions. The standard water level index (SWI) and the standard runoff index (SRI) are employed to identify hydrological drought in the lake-catchment-river system. The appropriate marginal distributions and copulas are selected by the corrected Akaike Information Criterion and Bayesian copulas selection method. The probability of hydrological drought in Poyang Lake in any given year is 16.6% (return period of 6 years), and droughts occurred six times from 2003 to 2013. Additionally, the joint probability of concurrent drought events between the lake and catchment is 10.1% (return period of 9.9 years). Since 2003, concurrent drought has intensified in spring due to frequent hydrological drought in the catchment. The joint probability of concurrent drought between the lake and the Yangtze River is 11.5% (return period of 8.7 years). This simultaneous occurrence intensified in spring, summer and autumn from 2003 to 2013 due to the weakened blocking effect of the Yangtze River. Notably, although the lake drought intensified in winter during the past decade, hydrological drought in the catchment and the Yangtze River did not intensify simultaneously. Thus, this winter intensification might be caused by human activities in the lake region. The results of this study demonstrate that the Poyang lake-catchment-river system has been drying since 2003 based on a statistical approach. An adaptation strategy should be urgently established to mitigate the worsening situation in the Poyang lake-catchment-river system. [ABSTRACT FROM AUTHOR]

Highlights: [•] We examined the long-term hydro-climatic changes of the Poyang Lake catchment. [•] We investigated the relative impacts of climate change and human activities. [•] Relative effects varied among sub-catchments under different decades. [•] Increased catchment streamflow was mainly affected by climate variability. [•] Comprehensive effect of specific human activities led to a decrease of streamflow. [Copyright &y& Elsevier]

Climate change and human activities have impacted the Poyang Lake Basin (PLB) greatly over the past decades, and have significantly changed the local ecological environment and hydrological cycle. Based on the daily records from 16 meteorological stations and 7 gauging stations in the Poyang Lake Basin from 1960 to 2015, the contributions of climate change and human activities to runoff variations under different timescales (annual, flood season, and non-flood season) were explored using the Mann-Kendall, Moving-T test, and a linear regression model. The results showed that on annual timescale, climate change accounted for 91.88% of the increased runoff depth. However, intensive human activities in the subbasins would have reduced the runoff depth in the Poyang Lake Basin. The impact of climate change on the variation of runoff depth increased during the flood season. Climate change and human activities contributed ~57% and ~42%, respectively. Both climate change and human activities could increase the runoff depth during the non-flood season. • Effect of precipitation on annual runoff depth is significant. • Climate change contributes greater to runoff depth from 1960 to 2015. • Human activities could increase the runoff depth during the non-flood season. [ABSTRACT FROM AUTHOR]

Abstract: The preparing technique of chemical solution deposition (CSD) for La0.85Ag0.15MnO3 and La0.85Ag0.1MnO3 colossal magnetoresistance (CMR) film is investigated. Polycrystalline-like La0.85Ag0.15MnO3 films are obtained on LaAlO3 (h 00) and YSZ (h 00) single-crystal substrates as a seed layer is not utilized. However, as a seed layer is used, an epitaxial-like La0.85Ag0.1MnO3 film can be successfully fabricated on LaAlO3 (h 00) single-crystal substrate. XRD shows that Ag atoms can substitute La atoms without forming any second phases. The magneto-transport property measurement shows that the polycrystalline-like La0.85Ag0.15MnO3 and the epitaxial-like La0.85Ag0.10MnO3 films behave as CMR effect in the whole temperature region below metal–insulator transition (T p) and in the vicinity of T p, respectively. The results indicate that the CSD method is a worthwhile technique for preparing manganite CMR films with tuning grain orientations. [Copyright &y& Elsevier]