254 research outputs found
A wave-induced stirring mechanism in the mid-depth equatorial ocean
A wave-induced stirring and transport mechanism for the mid-depth equatorial ocean is proposed and examined using both analytic linear equatorial wave solutions and a fully nonlinear reduced-gravity model. The study of kinematic stirring using the linear solutions suggests that a superimposition of a few simple equatorial waves can lead to strong Lagrangian stirring and transport along the equator. In particular, a combination of an annual long Rossby wave and a high-frequency Yanai wave appears to be most effective in producing strong stirring in the interior equatorial region. Further investigations of stirring properties using an inverted, fully nonlinear reduced gravity shallow-water model support the results of the kinematic stirring study. By evaluating the finite-time estimates of Lyapunov exponents, we identified two regions where chaotic stirring is most active. One is the western boundary region where short Rossby waves likely play a dominant role in producing the strong chaotic stirring. The other is the equatorial waveguide where a low-frequency Rossby wave prescribes the pattern of the stirring geometry, and a high-frequency Yanai wave plays a role of stirring the fluid. The proposed stirring mechanism provides a plausible explanation of the observed chlorofluorocarbon distribution found in the mid-depth equatorial Atlantic Ocean
Terephthalic acid–4,4′-bipyridine (2/1)
In the title compound, 2C8H6O4·C10H8N2, the 4,4′-bipyridine molecule is located on an inversion centre. In the crystal structure, strong intermolecular O—H⋯N hydrogen bonds between the terephthalic acid and 4,4′-bipyridine molecules lead to the formation of chains with graph-set motif C
2
2(8) along the diagonal of the bc plane
catena-Poly[[bis(p-toluenesulfonato-κO)palladium(II)]bis(μ-1,3-di-4-pyridylpropane-κ2 N:N′)]
In the title compound, [Pd(C7H7O3S)2(C13H14N2)2]n, the metal ion, located on a twofold rotation axis, exhibits a slightly distorted octahedral coordination environment, with bond angles that deviate by at most 2.2° from an ideal geometry, completed by two O atoms from two deprotonated p-toluenesulfonic acid ligands and four N atoms from four 1,3-di-4-pyridylpropane ligands. One of the sulfonate O atoms is disordered over two positions [ratio 0.70 (5):0.30 (5)]
Recommended from our members
The influence of local officials' promotion incentives on carbon emission in Yangtze River Delta, China
China's carbon emissions is heavily influenced by economic growth, which can be largely related to the local officials' promotion incentives. The current study was conducted to test the hypothesis that the influence of local officials' individual characteristics on carbon emissions was driven by the promotion incentives. Yangtze River Delta where carbon emissions accounted for around 13.95% of China's total emissions was selected as the research area. The multiple linear regression model was applied to determine the relationship between local officials' characteristics and total carbon emissions and carbon emissions from different sectors. The results indicated that local officials' promotion source, tenure and age significantly influenced the total carbon emission. Despite insignificance influence of officials' academic level on carbon emissions, the professional background in economics and management had a significant influence on carbon reduction. Our results indicated the importance of local officials' promotion incentives for carbon emission in China. Therefore, low carbon development should be included as an important part of official promotion system
Recommended from our members
Zirconium-Catalyzed Atom-Economical Synthesis of 1,1-Diborylalkanes from Terminal and Internal Alkenes
A general and atom-economical synthesis of 1,1-diborylalkanes from alkenes and a borane without the need for an additional H2 acceptor is reported for the first time. The key to our success is the use of an earth-abundant zirconium-based catalyst, which allows a balance of self-contradictory reactivities (dehydrogenative boration and hydroboration) to be achieved. Our method avoids using an excess amount of another alkene as an H2 acceptor, which was required in other reported systems. Furthermore, substrates such as simple long-chain aliphatic alkenes that did not react before also underwent 1,1-diboration in our system. Significantly, the unprecedented 1,1-diboration of internal alkenes enabled the preparation of 1,1-diborylalkanes. © 2020 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA
Bis(ethanolato-κO)(5,10,15,20-tetraphenylcalix[4]pyrrole)manganese(III) hexafluorophosphate
The title compound, [Mn(C2H5O)2(C44H28N4)]PF6, was synthesized from manganese(III) 2,4-pentanedionate and 5,10,15,20-tetraphenylcalix[4]pyrrole by a hydrothermal reaction. The MnIII atom is located on an inversion centre and the asymmetric unit comprises one half-formula unit. The MnIII ion is hexacoordinated by four N atoms from one 5,10,15,20-tetraphenylcalix[4]pyrrole ligand and two O atoms from two deprotonated ethanol molecules. The equatorially located atoms (the Mn and four N atoms) are planar. The dihedral angles between the planes of the phenyl rings and the equatorial plane are 53.3 (2) and 81.8 (2)°. One hexafluorophosphate anion balances the charge
Spatio-temporal variations of health costs caused by chemical fertilizer utilization in China from 1990 to 2012
The health impacts caused by chemical fertilizer utilization have challenged long-term sustainable development in many countries, particularly developing countries. Based on the emergy analysis method, we estimated the temporal and spatial variations of the health costs, through atmospheric, water, and soil pathways, of chemical fertilizer utilization in China during the period from 1990 to 2012. The results showed an obvious increasing trend of health costs from 1.8 billion Yuan in 1990 to 23.0 billion Yuan in 2012, while the ratio of health costs to agriculture output value declined slowly and became stable in recent years. Regional differences were remarkable and were significantly correlated to the levels of economic development (r = 0.843 and p < 0.001) and crop-sown area in the region (r = 0.588 and p < 0.001). Economically developed regions, especially the eastern coastal provinces, had much higher costs than the western regions. Meanwhile, fertilizer consumption shifted from the eastern to the northwest region, which was the same as the health costs. This study provides a reference to estimate the health costs of fertilizer utilization, and the results highlight the importance of sustainable development in China
- …