High-resolution peat humification records were obtained from Dajiuhu of the Shennongjia Mountains and Qianmutian of the Tianmu Mountains to study climate changes in EastChina. The analyses of pollen, organic matters, TOC, and Rb/Sr indicate a high degree of peat humification and thus strong decomposition of organic matter when climate was dry. Conversely, when climate was humid, the degree of humification is low because peat was preserved in a waterlogged condition. Peat humification from Dajiuhu occurred not only during the Younger Dryas (about 11.4-12.6 cal ka BP), the Bøl-ling-Allerød Warm Period (12.6-15.2 cal ka BP), and the Oldest Dryas (about 15.2-16.0 cal ka BP), but also during the early Holocene (about 11.4-9.4 cal ka BP), the 8.2 cal ka BP cold event, and the Holocene Optimum (about 7.0-4.2 cal ka BP). Both peat humification records since nearly 5 ka BP are consistent, showing that mountain peatland has synchronous responses to the East Asia monsoon-induced precipitation. The LOI data confirm the above observation. The monsoon precipitation since nearly 5 ka BP recorded in these two peat profiles can be divided into three phases. During 4.9-3.5 ka BP, precipitation amount was high but fluctuated greatly. During 3.5-0.9 ka BP, precipitation amount was low. During 0.9-0 ka BP, degree of humification reduced gradually, indicating the increase of monsoon precipitation. Contrast to other high-resolution records from East China monsoon region shows that the monsoon precipitation records of the two peat profiles since nearly 16 ka BP are controlled by a common forcing mechanism of summer solar radicalization in the Northern Hemisphere.
A series
of new biobased benzoxazine monomers were synthesized
by reacting amino acid methyl ester and disphenolic acid methyl ester/eugenol
(E) with paraformaldehyde by Mannich condensation reaction. The chemical
structures of these biobenzoxazine monomers were characterized by 1H NMR, 13C NMR, mass spectrum, and Fourier transform
infrared (FTIR). Their curing behaviors were examined by differential
scanning calorimetry (DSC) and FTIR spectroscopy. Thermogravimetric
analysis was utilized to evaluate the thermal stability of the polybenzoxazines.
The poly(E−lyme) showed highest thermal stability in these
obtained biothermosets, T
d10% of 373 °C
and char yield of 47%, respectively. Furthermore, these polybenzoxazines
showed good application in the CO2 adsorption field as
the carbon precursor, and the activated carbon materials from poly(E−lyme)
had a high surface area of up to 1194 m2 g–1. The remarkably high CO2 adsorption capacity of 5.82
mmol/g was observed on the carbon material ELF0 at 800 mm Hg and 273
K.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.