Browsing by Author "Zhou, J"

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    Earliest archaeobiological evidence of the broadening agriculture in China recorded at Xishanping site in Gansu Province
    (Science in China Press (SCP), 2007-11) Li, XQ; Zhou, XY; Zhou, J; Dodson, JR; Zhang, HB; Shang, X
    The crop types and agricultural characteristic are reconstructed using the archaeobiological proxies of pollen, seed and phytolith at Xishanping site in Gansu Province between 5250 and 4300 cal a BP. The agricultural activity strengthened in Xishanping from 5100 cal a BP. It appeared the earliest cultivation of prehistoric rice in the most northwest China at 5070 cal a BP. The sudden disappearance of conifers and expansion of chestnut trees is likely to be the result of selective hewing of conifers and cultivation of chestnuts at about 4600 cal a BP. There existed 8 crop types of foxtail millet, broomcorn millet, rice, wheat, barley, oats, soybean and buckwheat at Xishanping between 4650 and 4300 cal a BP, which cover the main crop types of the two origin centers of East and West Asia. Not only has the wheat and barley been approved to spread to northwestern China, but the earliest complexity agriculture in Neolithic China appeared in Tianshui, Gansu Province. © 2007, Science in China Press (SCP)
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    Increases of population and expansion of rice agriculture in Asia, and anthropogenic methane emissions since 5000 BP
    (Elsevier, 2009-06-01) Li, XQ; Dodson, JR; Zhou, J; Zhou, XY
    CO2 and CH4 composition of the atmosphere increased rapidly following the industrial revolution. Recently Ruddiman has suggested that increases in the anthropogenic contribution to atmospheric greenhouse gases had actually begun thousands of years earlier. Research on climates indicates that a cooling and drying trend developed from about 5000 BP across the Asian monsoonal region. Archaeological and biological data reveal that from about the same time there was an important transition point corresponding to the rapid growth of population and expansion of cultivated rice areas. Extensive deforestation also occurred from this time. The expansion of rice agriculture and extended wetland areas provided more sources of methane emissions, and thus contributed to greenhouse gas budgets. The climate impacts of increased anthropogenic methane emissions were possibly counterbalanced in part by any natural decrease from orbital forcing. The methane contribution from rice paddy areas is estimated to be smaller than 250 ppb for the middle-late Neolithic. The 1000-ppb methane rise after industrial era coincides closely with the rapid growth of global human populations, and anthropogenic driven sources. © 2008, Elsevier Ltd.
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    Quantifying moisture recycling of a leeward oasis in arid central Asia using a Bayesian isotopic mixing model
    (Elsevier, 2022-10) Wang, S; Wang, L; Zhang, MJ; Shi, Y; Hughes, CE; Crawford, J; Zhou, J; Qu, D
    Locally recycled moisture from transpiration and surface evaporation is of great importance in the terrestrial hydrological cycle, especially in the widely distributed oases across arid central Asia. Quantitative assessment of the proportional contribution of recycled moisture to local precipitation, i.e., the recycling ratio, is useful to understand the land-air interaction as well as the anthropogenic impact on the regional water cycle. Here we analyzed the stable hydrogen and oxygen isotopes in precipitation samples collected at six stations across the Kaxgar-Yarkant Oasis in the western Tarim Basin of central Asia from April 2018 to June 2020. Using this data, the moisture recycling ratio in this typical oasis was assessed using a Bayesian three-component isotopic mixing model. For the plain stations, the annual weighted mean δ18O value in precipitation ranged from −5.94 ‰ to −1.46 ‰, and the mountain station has a lower annual mean precipitation isotopic ratio. The average recycling ratio during the summer months ranged between 17.0 % and 63.9 % for each sampling station in the Kaxgar-Yarkant Oasis, and the proportional contribution from transpiration ranged from 15.1 % to 61.3 %. The contribution of plant transpiration to local precipitation is much larger than that of surface evaporation. The recycled portion in total precipitation amount may increase the local precipitation under an oasis expansion background but is insufficient to change the arid background. In addition, the Bayesian isotopic mixing model is promising to determine the recycling ratio in an arid setting, and provides more spatial details than the climate reanalysis-based calculation. © 2022 Elsevier B.V.
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    The temperature-dependent phase transformation and microstructural characterisation in In-Sn solder alloys
    (Springer Nature, 2023-05-16) Zhou, J; Tan, XF; Gu, QF; McDonald, SD; Nogita, K
    Indium-based solder alloys are considered candidates for the next generation of low-temperature solder materials, especially for superconducting joints because of the properties of the β-In3Sn phase. The temperature-dependent phase transformation and thermal expansion behaviour of two different solder compositions including In-35Sn (in wt.%) and In-25.6Sn have been characterised using an in situ synchrotron powder X-ray diffraction method. The c-axis of the β-In3Sn unit cell in the In-35Sn alloy exhibited a complex relationship with increasing temperature compared to the positive increasing trend in In-25.6Sn due to the temperature-dependent solubility of Sn in β-In3Sn and change in the volume fraction of phases commencing at 80°C. In situ heating scanning electron microscopy recorded a real-time melting-solidification microstructure variation and phase transition during annealing at 90°C that was further analysed using energy dispersive X-ray spectroscopy. The observations are discussed with respect to the lattice parameters of the γ-InSn4 and β-In3Sn phases and the proportions and composition of both phases present within the alloys. © 2023 The Authors - Open Access - funded through CAUL.