[C, N, P, K Stoichiometric Characteristic of Leaves, Root and Soil in Different Abandoned Years in Loess Plateau].

The research of plant ecological stoichiometry characteristics, nutrients distribution and their changes is of great significance to explain the response and adaptation of plants to environmental change. Leaves, root and soil from eight different abandoned years in Yanhe River basin were selected to study the content, characteristic ratio and distribution of carbon ( C) , nitrogen (N) , phosphorus (P), potassium (K). The results showed that the C, N, P, K contents of plant leaves were 444.

[Impact of micro-landform on grassland plant comniunity structure and function in the hilly Loess Plateau region, China].

In order to analyze the impact of micro-landform on grassland plant community structure and function, species composition, aboveground and belowground biomass, and annual fine root production at different slope aspects (sunny slope and shady slope) and different slope positions (top, upper, middle and lower) were investigated in the hilly Loess Plateau region. The results showed that grassland communities were mainly composed of plants species belonging to Compositae, Poaceae and Leguminosae. The aboveground and belowground biomass and annual fine root production of community were 164.

The reduction of surface plasmon losses in quasi-suspended graphene.

Highly confined surface plasmons on graphene attract substantial interest as potential information carriers for highly integrated photonic data processing circuits. However, plasmon losses remain the main obstacle for implementation of such devices. In near-field microscopic experiments performed at the wavelength of 10 μm we show that a substantial reduction of plasmon damping can be achieved by placing a nanometric polymer nano-dots spacer between the graphene layer and the supporting silicon oxide slab making graphene quasi-suspended.

Graphene-based tunable plasmonic Bragg reflector with a broad bandwidth.

We propose and numerically analyze a plasmonic Bragg reflector formed in a graphene waveguide. The results show that the graphene plasmonic Bragg reflector can produce a broadband stopband that can be tuned over a wide wavelength range by a small change in the Fermi energy level of graphene. By introducing a defect into the Bragg reflector, we can achieve a Fabry-Perot-like microcavity with a quality factor of 50 for the defect resonance mode formed in the stopband.