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Different Patterns of Changes in Foliar Carbon Isotope Composition Along Altitude

He Z., Zhan S., Wang W., Hu L., Wu S.

Polish Journal of Ecology

2017

Vol. 65, nr 2

227--235

Three types of alpine plant species, Carex montis-everestii, Quercus aquifolioides and Stipa capillacea, along an altitudinal gradient of 3005-5025 m on the Tibetan Plateau, were chosen to test the generality of the hypothesis that foliar carbon isotope composition (δ13C) of C3 plants increases significantly with altitude and to determine climate drivers shaping its altitudinal pattern. Temperature and relative humidity showed significantly negative correlations with altitude; however, precipitation and soil water potential remained unchanged with altitude. Foliar δ13C of C. montis-everestii, Q. aquifolioides, S. capillacea alone or combined together did not significantly increase with altitude, which does not support the leading hypothesis of increased foliar δ13C with altitude. There was no difference in foliar δ13C among all three species. Multi-factor correlation analyses showed that temperature, precipitation and relative humidity alone did not affect foliar δ13C of C. montis-everestii and S. capillacea, but conferred significant effects on foliar δ13C of Q. aquifolioides.

Influence of space charged particles on satellite optical communication system

Hou R., Zhao S., Xu J., Wu J., Li Y., Zhan S., Shi L., Fang S.

Optica Applicata

2009

Vol. 39, nr 2

251-265

Although research of satellite optical communication system has been carried out for many years, there is scarce literature to comprehensively analyze the influence of space environment on satellite optical communication system. Different kinds of particles and fields exist in the space environment, including high energy charged particles, solar radiation, plasma environment, space fragment, etc. The Influence of space charged particles on satellite optical communication system was investigated in detail, which mainly related to single event upset (SEU), total dose effect and plasma environment. For SEU analysis the relation between single proton upset rate and satellite orbit was analyzed in detail. The reliability index of equipment based on SEU was proposed, the numerical calculation results have proved that the SEU effect was relatively less and corresponded to higher reliability of SRAM/MOS equipment under lower orbit altitude and inclination. For plasma environment analysis there is no obvious influence of plasma on laser signal transmission. But charging and discharging processes on satellite surface would lead to the malfunction of satellite communication system. The influence of charged particles and its related plasma on satellite optical communication system was investigated, which would be helpful for the design and the improvement of performance of satellite optical communication system.