Differential resistance and resilience of functional groups to livestock grazing maintain ecosystem stability in an alpine steppe on the Qinghai-Tibetan Plateau

2019 ◽  
Vol 251 ◽  
pp. 109579 ◽  
Author(s):  
Hasbagan Ganjurjav ◽  
Yong Zhang ◽  
Elise S. Gornish ◽  
Guozheng Hu ◽  
Yue Li ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Functional Groups ◽  
Differential Resistance ◽  
Livestock Grazing ◽  
Ecosystem Stability ◽  
Alpine Steppe

Negative Differential Resistance of Graphene Oxide/Sulphur Compound

2021 ◽  
Vol 67 ◽  
pp. 25-31
Author(s):  
Sophia R. Figarova ◽  
Elvin M. Aliyev ◽  
Rashad G. Abaszade ◽  
R.I. Alekberov ◽  
Vagif R. Figarov
Keyword(s):  
Graphene Oxide ◽  
Functional Groups ◽  
Negative Differential Resistance ◽  
Characteristic Curve ◽  
Differential Resistance ◽  
Localized States ◽  
Sulphur Compound ◽  
X Ray Diffraction ◽  
Current Voltage ◽  
Current Voltage Characteristics

Graphene oxide/sulphur compound was synthesized by Hammers method. The chemical composition, presence/quantity of functional groups, exfoliation level, number of layers, crystallite size of graphene oxide/sulphur were characterized by X-ray diffraction, Raman spectroscopy, and scanning electron microscopy images. The current-voltage characteristics of the samples were measured in air at room temperature. In the I - V characteristic curve of graphene oxide/sulphur compound with the ratio of oxygen to carbon of 3.54 and that to sulphur of 42.54, negative differential resistance was observed. The negative differential resistance is attributed to current carrier transitions between the localized states formed by functional groups.

Soil conservation service on the Tibetan Plateau, 1984–2013

2018 ◽  
Vol 109 (3-4) ◽  
pp. 445-451 ◽  
Author(s):  
Jian SUN ◽  
Yu LIU ◽  
Tiancai ZHOU ◽  
Guohua LIU ◽  
Jingsheng WANG
Keyword(s):  
Soil Erosion ◽  
Tibetan Plateau ◽  
Soil Conservation ◽  
Economic Value ◽  
Equation Model ◽  
The Tibetan Plateau ◽  
Alpine Steppe ◽  
Ecological Protection ◽  
State And Local ◽  
Regional Ecological Security

ABSTRACTSoil erosion can pose a serious problem to environmental quality and sustainable development. On the Tibetan Plateau, soil erosion is one of the main challenges to regional ecological security. Our analysis investigates soil erosion and evaluates its economic value in alpine steppe, alpine meadow, alpine desert steppe and forest ecosystems on the Tibetan Plateau. Analysis was carried out from 1984 to 2013. The results show that the annual average potential soil erosion, practical soil erosion and soil conservation calculated by the Revised University Soil Loss Equation model were 2.19×109ta–1, 2.16×109ta–1 and 2.72×107ta–1, respectively. The economic value of retaining soil nutrients, reducing the formation of wasteland and the economic benefit of reducing sediment deposition were 1.98×108RMBa–1, 2.55×1012RMBa–1 and 7.44×104RMBa–1, respectively. From comparing different ecosystems, we found that the forest ecosystem had the greatest soil retention and economic values. We also found that the potential and actual soil erosion values were extremely high on the Tibetan Plateau. The study highlights that state and local policymakers must give greater emphasis to ecological protection in the future.

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