Restored vegetation is more resistant to extreme drought events than natural vegetation in Southwest China.

Large scale Ecosystem restoration projects (ERPs) have been implemented to restore vegetation and increase carbon stocks across China. However, whether restored vegetation is strongly resistant to Extreme drought events (EDEs) remains unclear, especially when compared to natural vegetation. Therefore, we used the standardized anomaly of 3-month Standard Precipitation-Evapotranspiration Index (SPEI) to characterize the spatial-temporal trends of EDEs, and figured out the capacity of restored vegetation to withstand the strongest EDE in Southwest China by analyzing their changes of Gross Primary Productivity (GPP) and Water Use Efficiency (WUE). The results showed that Southwest China had experienced six typical EDEs with increasing frequency and severity from 1982 to 2017, particularly the EDE during 2009-2010 (EDE 2009/2010) which had the longest duration and strongest severity. Overall, the EDE 2009/2010 substantially suppressed the vegetation GPP and ecosystem WUE in both restored and natural vegetation area. Compared with natural vegetation, the GPP and WUE of restored vegetation was relative higher and moreover, their GPP decreased more slowly during the EDE 2009/2010 and increased more quickly during the recovery period. This indicates that restored vegetation had a higher drought resistance to the EDE than natural vegetation. Additionally, karst landforms have a stronger negative impact on vegetation GPP and WUE during the EDE. Furthermore, the reduction in the afforestation areas was more obviously observed than that in natural forest areas. Therefore, we suggest that vegetation suitable for regional characteristics should be selected during vegetation restoration, such as afforestation in the non-karst areas.

Land Use and Climate Change Altered the Ecological Quality in the Luanhe River Basin.

Monitoring and assessing ecological quality (EQ) can help to understand the status and dynamics of the local ecosystem. Moreover, land use and climate change increase uncertainty in the ecosystem. The Luanhe River Basin (LHRB) is critical to the ecological security of the Beijing-Tianjin-Hebei region. To support ecosystem protection in the LHRB, we evaluated the EQ from 2001 to 2020 based on the Remote Sensing Ecological Index (RSEI) with the Google Earth Engine (GEE). Then, we introduced the coefficient of variation, Theil-Sen analysis, and Mann-Kendall test to quantify the variation and trend of the EQ. The results showed that the EQ in LHRB was relatively good, with 61.08% of the basin rated as 'good' or 'excellent'. The spatial distribution of EQ was low in the north and high in the middle, with strong improvement in the north and serious degradation in the south. The average EQ ranged from 0.58 to 0.64, showing a significant increasing trend. Furthermore, we found that the expansion of construction land has caused degradation of the EQ, whereas climate change likely improved the EQ in the upper and middle reaches of the LHRB. The results could help in understanding the state and trend of the eco-environment in the LHRB and support decision-making in land-use management and climate change.

Constructing a three-dimensional nano-crystalline diamond network within polymer composites for enhanced thermal conductivity.

In order to meet the requirement of thermal performance with the rapid development of high-performance electronic devices, constructing a three-dimensional thermal transport skeleton is an effective method for enhancing the thermal conductivity of polymer composites. In this work, a three-dimensional porous diamond framework was prepared by depositing nano-crystalline diamond on alumina foam which was impregnated with epoxy to obtain a nano-crystalline diamond@alumina foam/epoxy composite. The epoxy composite with nano-crystalline diamond@alumina foam demonstrated a thermal conductivity of 2.21 W m-1 K-1, which was increased by 1063% in comparison with pure epoxy. The thermal conductivity of the epoxy composite measured under various conditions and heat transport applications demonstrates that it possesses excellent thermal transportation and stability properties. This work provides a new idea to significantly enhance the thermal transportation properties of epoxy composites in the application of advanced packaging materials.

Rapid Invasion of Spartina Alterniflora in the Coastal Zone of Mainland China: Spatiotemporal Patterns and Human Prevention.

Given the extensive spread and ecological consequences of exotic Spartina alterniflora (S. alterniflora) over the coast of mainland China, monitoring its spatiotemporal invasion patterns is important for the sake of coastal ecosystem management and ecological security. In this study, Landsat series images from 1990 to 2015 were used to establish multi-temporal datasets for documenting the temporal dynamics of S. alterniflora invasion. Our observations revealed that S. alterniflora had a continuous expansion with the area increasing by 50,204 ha during the considered 25 years. The largest expansion was identified in Jiangsu Province during the period of 1990-2000, and in Zhejiang Province during the periods 2000-2010 and 2010-2015. Three noticeable hotspots for S. alterniflora invasion were Yancheng of Jiangsu, Chongming of Shanghai, and Ningbo of Zhejiang, and each had a net area increase larger than 5000 ha. Moreover, an obvious shrinkage of S. alterniflora was identified in three coastal cities including the city of Cangzhou of Hebei, Dongguan, and Jiangmen of Guangdong. S. alterniflora invaded mostly into mudflats (>93%) and shrank primarily due to aquaculture (55.5%). This study sheds light on the historical spatial patterns in S. alterniflora distribution and thus is helpful for understanding its invasion mechanism and invasive species management.

Change Of Nano Material Electrical Characteristics For Medical System Applications.

Amorphous nano oxides (AO) are intriguing advanced materials for a wide variety of nanosystem medical applications including serving as biosensors devices with p-n junctions, nanomaterial-enabled wearable sensors, artificial synaptic devices for AI neurocomputers and medical mimicking research. However, p-type AO with reliable electrical properties are very difficult to obtain according to the literature. Based on the oxide thin film transistor, a phenomenon that could change an n-type material into a p-type semiconductor is proposed and explained here. The typical In-Ga-Zn-O material has been reported to be an n-type semiconductor, which can be changed by physical conditions, such as in processing or bias. In this way, here, we have identified a manner to change nano material electrical properties among n-type and p-type semiconductors very easily for medical application like biosensors in artificial skin.

[The Effect of Plasma Spatially Resolved During Diamond Film Deposited with HFCVD].

Optical emission spectroscopy (OES) was used to detect the plasma distribution during the depositing process of diamond films with hot filament chemical vapor deposition (HFCVD) method using acetone as carbon source. The surface and cross section of deposited diamond films were characterized by scanning electron microscopy (SEM) and their quality was tested with Raman spectroscopy. OES results showed that the intensity of active species near the center is higher than that in marginal area in the case of linear array of hot filament. It is because of the higher temperature and stronger cracking ability near the filament. The variety of the characteristic peak intensity in central region is more gently than that of the plasma ball. Thermal radiation decreased when the distance from the hot filament increases, which results in less CH，CO groups cracked from acetone, lower intensity of Hα，Hß excited by hydrogen and higher concentration of C2 group produced by reaction. SEM and Raman results showed that the quality of deposited diamond films deteriorated when the distance between hot filament and substrate varies from 4.5, 5.5 to 6.5 mm, which matches well with OES results.