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Litterfall is a good indicator of overall forest functions in forest ecosystems. Globally, forest litterfall has been extensively investigated, however, there is a lack of long‐term data analysis to show the various litterfall components in relation to environmental factors on the monthly and yearly scales. Here, monthly (May–October) and annual (1981–2018) litterfall including leaves, twigs, bark, reproductive, and miscellaneous fractions were collected in a mixed mature Pinus koraiensis forest on Changbai Mountain in Northeast, China, across 30 years. Based on these long‐term litterfall data, we analyzed the seasonal and annual variations in different litterfall fractions and the internal/external drivers. We observed that both the leaf and total litterfall exhibited a strong, similar seasonal pattern, with the highest levels between September and October, and the annual litterfall had an "S‐shaped" increasing pattern from 1981 to 2018. The other litterfall fractions showed distinct monthly and yearly fluctuations across the 30 years. Mean monthly evapotranspiration and temperature (minimum and maximum) were the best predictors for monthly litterfall. By contrast, the models that best predicted the annual litterfall production included mean annual precipitation and mean monthly precipitation and temperature in May and October. Our study, using a unique dataset of detailed long‐term litterfall dynamics, has potentially major significance for enhancing our understanding of the role of climatic factors controlling forest litterfall amount and seasonality in temperate mixed mature forests. This insight is of paramount importance for modeling and estimating soil carbon sequestration and nutrient cycling of temperate forests under climate change. Plain Language Summary: Forest litterfall is very important for nutrient cycling in forest ecosystems. Many researchers have studied forest litterfall, but still, there is an obvious lack of long‐term data analysis to show the relationships between forest litterfall and environmental factors. In this study, we analyzed the monthly and annual litterfalls of various components (leaf, reproductive, twig, bark, and miscellaneous litterfall) collected over 30 years in a mixed broad‐leaved Pinus koraiensis old‐growth forest on Changbai Mountain in northeastern China, in relation to climatic factors. We found that the highest monthly values of both leaf and total litterfall occurred during September‐October, and the annual litterfall of all components had an increasing trend from 1981 to 2018. The monthly litterfall was strongly influenced by the mean monthly evapotranspiration and temperature (minimum and maximum). The annual litterfall was mainly influenced by the mean annual precipitation, mean monthly precipitation, and temperature in May and October. These long‐term data based findings have important implications for better understanding the role of climatic factors on forest litterfall dynamics under climate change. Key Points: Leaf and total litterfall exhibited a strong and similar seasonal patternThere was an "S‐shaped" increasing pattern in the annual litterfallContrasting climatic factors controlled seasonal and annual litterfall dynamics [ABSTRACT FROM AUTHOR]

Aluminum (Al)-based materials composited of different low melting point materials were prepared by mechanical ball-milling. Hydrogen production using these materials was investigated to help resolving the safety issues associated with the storage and transportation of hydrogen. The phase composition and microstructure of the Al-based composited materials were examined using X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. As observed in this study, the addition of low melting point metals (such as Sn, Bi and In) helped to lower the initial Al-water reaction temperature and to increase the yield in the production of hydrogen. Samples of optimized compositions, Al-6% Sn-4% Bi and Al-6% Sn-4% In, were found to exhibit high hydrogen production yields of up to 448 and 515 mL, respectively. Meanwhile, their hydrogen generation rates were increased. [ABSTRACT FROM AUTHOR]

In order to improve the lifespan of electrodes used for spot-welding galvanised steel plates, electrodes coated with TiB2-TiC composite were studied. Scanning electron microscope and X-ray diffraction were employed to analyse the failure process of TiB2-TiC composite-coated electrodes when they were used for spot-welding galvanised steel plates. The analysis results show that the influence of mechanical force and welding heat, along with other factors, could lead to the generation of cracks in the originally complete TiB2-TiC composite coating. The developed cracks weave into a mesh, which enhances the extent of alloying between the TiB2-TiC composite-coated electrode and the zinc coating of the galvanised steel plate. Because of the influence of local alloying, the coatings tend to peel off in pieces, resulting in a higher level of alloying and the final failure of TiB2-TiC composite-coated electrodes. Failure of TiB2-TiC composite-coated electrodes is the result of both alloying and plastic deformation. [ABSTRACT FROM AUTHOR]

Single tracks of selective laser melted FeAl intermetallics were studied in this paper in order to manufacture a perfect part. The morphology evolution of single tracks with the variation in laser scanning speed was analysed, and the bottom heating of substrate or premelted layer was proposed to obtain a better flattening degree of molten FeAl droplets. Reasonable mechanisms for morphology evolution were provided. It is revealed that with increasing the laser scanning speed, the surface tension gradient plays an important role in morphology evolution, while the bottom heating of substrate or premelted layer can counteract the contraction effect of FeAl particles induced by laser scanning speed. [ABSTRACT FROM AUTHOR]