[1] Glycerol dialkyl glycerol tetraether (GDGT) membrane lipids in surface sediments from 24 lakes in China and Nepal were analyzed. The result shows that branched GDGT lipids occur widely in the studied lake sediments. The different distribution of branched GDGTs between the Chinese soils from Weijers et al. (2007b) and the Chinese lake sediments indicates that the branched GDGTs in the lacustrine sediment are the mixture of allochthonous and autochthonous branched GDGTs. Our result supports the suggestion that temperature is the principal factor affecting the distribution of GDGTs. Seasonality, sources, and precipitation increase the uncertainty of the correlation between the methylation index of branched tetraethers (MBT)/cyclization ratio of branched tetraethers (CBT) proxy and the temperature. The correlations of the MBT/CBT index with mean annual air temperature (T) for the global lakes are T = 6.803 − 7.062 × CBT + 37.090 × MBT (n = 139, p < 0.0001, R 2 = 0.62, and RMSE = 5.24°C); for the global lakes with pH < 8.5, T = 3.949 − 5.593 × CBT + 38.213 × MBT (n = 100, p < 0.0001, R 2 = 0.73, and RMSE = 4.27°C). The significant correlation suggests that the MBT/CBT proxy might be used as a potential paleotemperature proxy in the limnic environment. The MBT/CBT proxy provides an independent way to evaluate and verify the sensitivities of the different proxies for paleotemperature reconstruction from lacustrine sediments.

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Traditional power supply method for moving electric railway vehicles is based on contact type power collection technology. This sometimes cannot meet the requirements of modern rail transportation. A new wireless power transfer (WPT) technology can offer significant benefits in modern rail transportation particularly in some stringent environments. This paper reviews the status and the development of rail transit power supply technology, and introduces a new challenging technology-inductive power transfer (IPT) technology for rail transit. Tesla established the underpinning of IPT technology and creatively and significantly demonstrated power transfer by using highly resonant tuned coils long time ago. However, only in recent years the IPT technology has been significantly improved including the transfer air-gap length, transfer efficiency, coupling factor, power transfer capability and so on. This is mainly due to innovative semiconductor switches, higher control frequency, better coil designs and high performance material, new track and vehicle construction techniques. Recent advances in IPT for rail transit and major milestones of the developments are summarized in this paper. Some important technical issues such as coupling coil structures, power supply schemes, segmentation switching techniques for long-distance power supply, and bidirectional IPT systems for braking energy feedback are discussed. Index Terms-Bidirectional energy transfer, inductive power transfer (IPT), magnetic coupling, rail transit, segmented power supply, wireless power transfer (WPT).

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