Nanjing University of Information Science and Technology

About: Nanjing University of Information Science and Technology is a education organization based out in Nanjing, China. It is known for research contribution in the topics: Precipitation & Aerosol. The organization has 14129 authors who have published 17985 publications receiving 267578 citations. The organization is also known as: Nan Xin Da.

Response of surface air temperature to small-scale land clearing across latitudes

Abstract: Climate models simulating continental scale deforestation suggest a warming effect of land clearing on the surface air temperature in the tropical zone and a cooling effect in the boreal zone due to different control of biogeochemical and biophysical processes. Ongoing land-use/cover changes mostly occur at local scales (hectares), and it is not clear whether the local-scale deforestation will generate temperature patterns consistent with the climate model results. Here we paired 40 and 12 flux sites with nearby weather stations in North and South America and in Eastern Asia, respectively, and quantified the temperature difference between these paired sites. Our goal was to investigate the response of the surface air temperature to local-scale (hectares) land clearing across latitudes using the surface weather stations as proxies for localized land clearing. The results show that north of 10 N, the annual mean temperature difference (open land minus forest) decreases with increasing latitude, but the temperature difference shrinks with latitude at a faster rate in the Americas [ 0.079 ( 0.010) C per degree] than in Asia [ 0.046 ( 0.011) C per degree]. Regression of the combined data suggests a transitional latitude of about 35.5 N that demarks deforestation warming to the south and cooling to the north. The warming in latitudes south of 35 N is associated with increase in the daily maximum temperature, with little change in the daily minimum temperature while the reverse is true in the boreal latitudes.

Graphitic C3N4 Decorated with CoP Co‐catalyst: Enhanced and Stable Photocatalytic H2 Evolution Activity from Water under Visible‐light Irradiation

Abstract: In this work, graphitic C3 N4 decorated with a CoP co-catalyst (g-C3 N4 /CoP) is reported for photocatalytic H2 evolution reaction based on two-step hydrothermal and phosphidation method. The structure of g-C3 N4 /CoP is well confirmed by XRD, FTIR, TEM, XPS, and UV/Vis diffuse reflection spectra techniques. When the weight percentage of CoP loading is 3.4 wt % (g-C3 N4 /CoP-3.4 %), the highest H2 evolution amount of 8.4×102 μmol g-1 is obtained, which is 1.1×103 times than that over pure g-C3 N4 . This value also is comparable with that of g-C3 N4 loaded by the same amount of Pt. In cycling experiments, g-C3 N4 /CoP-3.4 % shows a stable photocatalytic activity. In addition, g-C3 N4 /CoP-3.4 % is an efficient photocatalyst for H2 evolution under irradiation with natural solar light. Based on comparative photoluminescence emission spectra, photoelectrochemical I-t curves, EIS Nyquist plots, and polarization curves between g-C3 N4 /CoP-3.4 % and pure g-C3 N4 , it is concluded that the presence of the CoP co-catalyst accelerates the separation and transfer of photogenerated electrons of g-C3 N4 , thus resulting in improved photocatalytic activity in the H2 evolution reaction.

Spatially nonrandom tree mortality and ingrowth maintain equilibrium pattern in an old-growth Pseudotsuga–Tsuga forest

Abstract: Mortality processes in old-growth forests are generally assumed to be driven by gap-scale disturbance, with only a limited role ascribed to density-dependent mortality, but these assumptions are rarely tested with data sets incorporating repeated measurements. Using a 12-ha spatially explicit plot censused 13 years apart in an approximately 500-year-old Pseudotsuga–Tsuga forest, we demonstrate significant density-dependent mortality and spatially aggregated tree recruitment. However, the combined effect of these strongly nonrandom demographic processes was to maintain tree patterns in a state of dynamic equilibrium. Density-dependent mortality was most pronounced for the dominant late-successional species, Tsuga heterophylla. The long-lived, early-seral Pseudotsuga menziesii experienced an annual stem mortality rate of 0.84% and no new recruitment. Late-seral species Tsuga and Abies amabilis had nearly balanced demographic rates of ingrowth and mortality. The 2.34% mortality rate for Taxus brevifolia was ...