Ling Zhang

High-density buckypapers were obtained by using well-aligned carbon nanotube arrays. The density of the buckypapers was as high as 1.39 g cm(-3), which is close to the ultimate density of ideal buckypapers. Then we measured the transport and mechanical properties of the buckypapers. Our results demonstrated that its electrical and thermal conductivities could be almost linearly improved by increasing its density. In particular, its superior thermal conductivity is nearly twice that of common metals, which enables it a lightweight and more efficient heat-transfer materials. The Young's modulus of the buckypapers could reach a magnitude over 2 GPa, which is greatly improved compared with previous reported results. In view of this, our work provided a simple and convenient method to prepare high-density buckypapers with excellent transport and mechanical properties.

Photocatalytic active spindle-like BiVO4 modified by polyaniline (PANI) was synthesized via a sonochemical approach for the first time. Scanning electron microscope (SEM) and transmission electron microscopy (TEM) images revealed that the photocatalysts are composed of well-crystallized small nanoparticles. The efficient photocatalytic activity in the degradation of a widely used dye, tetraethylated rhodamine (RhB), and phenol under visible-light irradiation (λ > 420 nm) was realized by the spindle-like PANI/BiVO4. Besides decoloring, reduction of the chemical oxygen demand (COD) concentration was also observed in the degradation of RhB, further demonstrating the photocatalytic performance of PANI/BiVO4. Additionally, the notable enhanced photocatalytic performance for phenol oxidation was also realized with the assistance of a little amount of H2O2. The enhanced photocatalytic activity could be attributed to the synergic effect between PANI and BiVO4, which promoted the migration efficiency of photogenerated electron−hole. According to experimental results, the possible photocatalytic mechanisms of the PANI/BiVO4 photocatalyst were proposed in order to guide the further improvement of its photocatalytic performance.

Abstract Quantification of the global irrigation water use (IWU) is crucial to understanding the anthropogenic disturbance of the natural hydrological cycle and optimal agricultural water management. However, it is challenging to obtain time series data with the conventional survey‐based approach, while the current satellite‐based IWU estimations are subject to data gaps and the model structure. In this paper, we propose a comprehensive framework to couple the different processes associated with irrigation and integrate multiple satellite observations to estimate the global IWU. The ensemble IWU estimate demonstrates an improved performance when compared to the IWU obtained from individual satellite observations. The results show reasonable correlation with the survey‐based irrigation water withdrawal in states of the US (bias = −0.42 km 3 ), provinces of China (bias = −3.10 km 3 ), and country statistics from the Food and Agriculture Organization (bias = −10.84 km 3 ). Large amounts of IWU are apparent in India, China, the US, Europe, and Pakistan, making up >70% of the global IWU. A general underestimation of IWU is found both in this work and previous studies, due to the coarse resolution and asynchronism of the various satellite products, the changes in irrigated areas, and the deficiency in detecting irrigation events under the case of saturated soil moisture. Nevertheless, we demonstrate advantages in integrating multiple satellite observations to reduce the uncertainty in estimating global IWU. However, additional efforts are needed to produce high‐quality and finer spatiotemporal resolution satellite‐based products, to further improve the accuracy of the global IWU estimation.

Ultrathin mesoporous Co₃O₄nanosheets electrodeposited on a stainless steel mesh (SS–Co₃O₄) exhibit high photothermal performance and possess superior PTC activity.