Browsing by Author "Peng, Jian"

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • How can virtual water trade reshape water stress pattern? A global evaluation based on the metacoupling perspective
    (2022-12) Du, Yueyue; Zhao, Dandan; Qiu, Sijing; Zhou, Feng; Peng, Jian
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    With water scarcity increasingly becoming a growing global risk, it is prevalent to explore water supply-demand interaction within and beyond national borders driven by global virtual water trade and its effects on water sustainability. However, there is little study on system integration of differential environmental impacts of various types of trade. Based on metacoupling framework highlighting human-nature interactions across space- within a place (intracoupling), between adjacent places (pericoupling), and between distant places (telecoupling), this study quantified the linkages and intensities of three kinds of coupling processes during global virtual water trade for the first time. Correspondingly, water stress changes under a set of trade scenarios were evaluated based on the indicator of UN SDG 6.4.2 to distinguish the influence of trade taking place on different spatial scales. Results show that during 2005–2015, local water resources supported 80% of global water consumption. Distant virtual water import was about 5 times in volume as large as adjacent virtual water import, alleviating 99.8% of global average water stress. Virtual water trade reduced water stress in 86% of developed countries and increased that in 71% of developing countries in 2005. Owing to trade, water stress in many countries with poor water resources endowment declined while that of many with relatively good endowment went up from 2005 to 2015. Our findings can help to systematically understand the influence of virtual water trade on water stress change and provide scientific guidance for sustainable water management and regional regulations.
  • Two-dimensional material-based saturable absorbers: towards compact visible-wavelength all-fiber pulsed lasers
    (2016) Luo, Zhengqian; Wu, Duanduan; Xu, Bin; Xu, Huiying; Cai, Zhiping; Peng, Jian; Weng, Jian; Xu, Shuo; Zhu, Chunhui; Wang, Fengqiu; Sun, Zhipei; Zhang, Han
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Passive Q-switching or mode-locking by placing a saturable absorber inside the laser cavity is one of the most effective and popular techniques for pulse generation. However, most of the current saturable absorbers cannot work well in the visible spectral region, which seriously impedes the progress of passively Q-switched/mode-locked visible pulsed fibre lasers. Here, we report a kind of visible saturable absorber-two-dimensional transition-metal dichalcogenides (TMDs, e.g. WS2, MoS2, MoSe2), and successfully demonstrate compact red-light Q-switched praseodymium (Pr3+)-doped all-fibre lasers. The passive Q-switching operation at 635 nm generates stable laser pulses with similar to 200 ns pulse duration, 28.7 nJ pulse energy and repetition rate from 232 to 512 kHz. This achievement is attributed to the ultrafast saturable absorption of these layered TMDs in the visible region, as well as the compact and all-fibre laser-cavity design by coating a dielectric mirror on the fibre end facet. This work may open a new route for next-generation high-performance pulsed laser sources in the visible (even ultraviolet) range.