Electrosynthesis of Pd/Au hollow cone-like microstructures for electrocatalytic formic acid oxidation

Pd/Au hollow cone-like microstructures (HCMs) have been electrodeposited on indium tin oxide (ITO) using a two-step protocol, which involves the nucleation pulse and succedent constant potential reduction in the presence of metal precursors and polyvinylpyrrolidone (PVP). Scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscope (XPS) were used to characterize the Pd/Au HCMs. The electrochemical results (cyclic voltammetry and chronoamperometry) testify that the Pd/Au HCMs exhibit significantly higher electrocatalytic activity and stability for the oxidation of formic acid than that of Pd/Au solid microhemispheres (SMHs). These attractive features are attributable to the unique hollow structures of Pd/Au with much higher electrochemical active surface areas and the exposure of favorable planes. Our work points to a new path for the preparation of Pd/Au HCMs, which are promising as electrocatalysts in direct formic acid fuel cell (DFAFC).     

Fine-grained histopathological cell segmentation through residual attention with prior embedding

In the task of histopathological cell segmentation, traditional algorithms struggle with cell edge processing, which leads to the blurring of cell edges. To strengthen the ability to learn the features of cell edges, this paper develops a novel deep neural network for robust and fine-grained cell segmentation. The proposed deep model mines global and local features by multiscale convolution and dilated convolution. Subsequently, the residual attention module is introduced in the third to fifth layers of the encoder; this module assigns a group of weight coefficients to all the deep features to boost the segmentation performance. In addition, to further improve the quality of the features in the decoder, we first introduce the strategy of U-Net for the extraction of prior information, where we filter the fused features and compress the features by using the prior information and the filtered features again to integrate more semantic information into the feature refinement in the decoding process. We tested the model on three public data sets: Multiorgan Nucleus Segmentation (MoNuSeg) (Dice 94.9%), Triple Negative Breast Cancer (TNBC) (Dice 95.4%) and Data Science Bowl (Dice 98.2%). Extensive experiments demonstrate the superior performance of our proposed method in comparison with that of state-of-the-art models; our method can effectively identify cell edges to produce fine-grained segmentation results.

     

随机风载下含裂纹故障风机增速箱动力学研究

裂纹故障会导致齿轮时变啮合刚度发生变化,进而引起系统振动响应改变.以风机增速箱为研究对象,考虑基圆和齿根圆不重合,采用改进能量法分别计算了各级齿轮副的时变啮合刚度,并计算、分析了太阳轮裂纹故障对啮合刚度的影响.风机增速箱运行于自然风载荷环境中,受时变转速和转矩激励,综合考虑齿侧间隙、时变啮合刚度、啮合误差等因素,利用集...     

Evolution of Tungsten Fiber-Reinforced Tungsten-Remarks on Production and Joining

Material issues pose a significant challenge for the design of future fusion reactors. These issues require new advanced materials to be developed. W-fiber-reinforced W-composite material (W _f/W) incorporates extrinsic toughening mechanisms increasing the resistance against failure and thus granting steps toward application in a future fusion reactor. W _f/W can be produced based on chemical vapor deposition or powder metallurgical routes. In this contribution, the efforts of upscaling the production of W _f/W will be reviewed based on recent results. In addition, the activities related to enabling large-scale production for new fusion applications are being studied. Herein, two main achievements are to be highlighted. First, an upscaled production is established to produce flat tile samples for joining tests on copper and steel, and second, a new method of joining W _f/W on copper is established and tested under high heat-flux conditions.