The delta O-18 signal preserved in paleoarchives is widely used to reconstruct past climate conditions. In many speleothems, this signal is classically interpreted via the amount effect. However, recent work has shown that precipitation delta O-18 (delta O-18(p)) is greatly influenced by convective processes distinct from precipitation amount, and new...
Porous silicon prepared by low-cost and scalable magnesiothermic reactions is a promising anode material for Li-ion batteries; yet, retaining good cycling stability for such materials in electrodes of practical loading remains a challenge. Here, we engineered the nanoporous silicon from a modified magnesiothermic reaction by controlled surface oxidization forming a...
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Areya, Wei Luob, Xiulei Jib,
Chongmin Wanga, Jun Liua,n, Ji-Guang Zhanga,n
aPacific Northwest National
An enantioselective 1,3-dipolar cycloaddition of 2-cyclo-hexene-1-one and azomethine ylide generated in situ from isatin and amino ester was developed by employing proline sulfonamide as the catalyst. Consequently, novel polycyclic spirooxindole scaffolds with three contiguous stereocenters were prepared in high yield (up to 95%) with excellent diastereo- (> 20:1 dr) and...
Converting CO2 to valuable materials is attractive.Herein, we report using simple metallothermic reactions to reduce atmospheric CO2 to dense nanoporous graphene. By using a Zn/Mg mixture as a reductant, the resulted nanoporous graphene exhibits highly desirable properties: high specific surface area of 1900 m2/g, a great conductivity of 1050 S/m...
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. Halsteda, Elliot S. Chonga, Jun Lub, Xingfeng Wanga,
Wei Luoa, Chih-Hung Changc, Youhai Wend, Shengqian Mae
Combined analyses of deep tow magnetic anomalies and International Ocean Discovery Program Expedition 349 cores show that initial seafloor spreading started around 33 Ma in the northeastern South China Sea (SCS), but varied slightly by 1-2 Myr along the northern continent-ocean boundary (COB). A southward ridge jump of ∼20 km...
The western United States has experienced large-scale degradation due to land use and land cover changes, invasion of annual grasses, and expansion of woody plants into grass and shrublands and the resultant altered fire regimes. These landscape-scale changes have coincided with declining mule deer (Odocoileus hemionus) populations, making habitat loss...
Lifestyle factors are responsible for a considerable portion of cancer incidence worldwide, but credible estimates from the World Health Organization and the International Agency for Research on Cancer (IARC) suggest that the fraction of cancers attributable to toxic environmental exposures is between 7% and 19%. To explore the hypothesis that...
Vocalizations of Indo-Pacific humpback dolphins (Sousa chinensis) in west Hong Kong waters were described from 12 recordings in 2010. A broadband hydrophone system recorded sounds. Vocalizations were characterized as broadband click trains, burst pulses, and narrowband frequency modulated sounds, including whistles generally similar to those of some other delphinid cetaceans....
Lignocellulosic biomass represents a vast and renewable source of fermentable sugar for
production of biofuels. However, native lignocellulose—comprised of cellulose,
hemicellulose and lignin—is refractory to degradation because the crystalline cellulose is
not easily hydrolyzed by cellulases. Standard chemical treatments of lignocellulose to
reduce the crystallinity of cellulose prior to enzymatic...
Using in-situ synchrotron X-ray scattering, we show that the structural evolution of various bulk metallic glass-forming liquids can be quantitatively connected to their viscosity behavior in the supercooled liquid near T[subscript g]. The structural signature of fragility is identified as the temperature dependence of local dilatation on distinct key atomic...