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Abstract Symmetric instability is a mechanism that can transfer geostrophic kinetic energy to overturning and dissipation. To date, symmetric instability has only been recognized to occur at the ocean surface or near topographic boundary layers. Analyses of direct microstructure measurements reveal enhanced dissipation caused by symmetric instability in the northwestern equatorial Pacific thermocline, which provides the first observational evidence of subsurface symmetric instability away from boundaries. Enhanced subsurface cross-equatorial exchange provides the negative potential vorticity needed to drive the symmetric instability, which is well reproduced by numerical modeling. These results suggest a new route to energy dissipation for large scale currents, and hence a new ocean turbulent mixing process in the ocean interior. Given the importance of vertical mixing in the evolution of equatorial thermocline, models may need to account for this mechanism to produce more reliable climate projections. 

Robust multivalent ion interaction in electrodes is a grand challenge of next-generation battery research. In this manuscript, we design molecularly-precise nanographene cathodes that are coupled with metallic Zn anodes to create a new class of Zn-ion batteries. Our results indicate that while electrodes with graphite or flat nanographenes do not support Zn-ion intercalation, the larger intermolecular spacing in a twisted peropyrene enables peropyrene electrodes to facilitate reversible Zn-ion intercalation in an acetonitrile electrolyte. While most previous Zn-ion batteries utilize aqueous electrolytes, the finding that nonaqueous Zn electrolytes can support intercalation in nanographenes is important for expanding the design space of nonaqueous multivalent batteries, which often possess higher voltages than their aqueous counterparts. Furthermore, because these nanographenes can be synthesized using a bottom-up approach via alkyne benzannulation, this work paves the way for future battery electrodes that contain other molecularly-precise nanographenes with tailored electrochemical properties. 

Abstract The structure and variations of the North Equatorial Counter Current (NECC) in the far western Pacific Ocean during 2014-2016 are investigated using repeated in-situ hydrographic data, altimeter data, Argo data, and reanalysis data. The NECC shifted ~1 degree southward and intensified significantly with its transport exceeding 40 Sv (1 Sv = 10 6 m 3 s -1 ), nearly double its climatology value, during the developing phase of the 2015/16 El Niño event. Observations show that the 2015/16 El Niño exerted a comparable impact on the NECC with that of the extreme 1997/98 El Niño in the far western Pacific Ocean. Baroclinic instability provided the primary energy source for the eddy kinetic energy (EKE) in the 2015/16 El Niño, which differs from the traditional understanding of the energy source of EKE as barotropic instability in low latitude ocean. The enhanced vertical shear and the reduced density jump between the NECC layer and the subsurface North Equatorial Subsurface Current (NESC) layer renders the NECC–NESC system baroclinically unstable in the western Pacific Ocean during El Niño developing phase. The eddy-mean flow interactions here are diverse associated with various states of the El Niño Southern Oscillation (ENSO). 

Abstract We present the inaugural synthesis of a chiral teropyrene achieved through a four‐fold alkyne benzannulation catalyzed by InCl₃, resulting in good yields. The product underwent thorough characterization using FT‐Raman and FT‐IR spectroscopies, demonstrating a close agreement with calculated spectra. X‐ray crystallographic analysis unveiled a notable twist in the molecule‘s backbone, with an end‐to‐end twist angle of 51°, consistent with computational predictions. Experimentally determined enantiomeric inversion barriers revealed a significant energy barrier of 23 kcal/mol, facilitating the isolation of enantiomers for analysis by circular dichroism (CD) and circularly polarized luminescence (CPL) spectroscopies. These findings mark significant strides in the synthesis and characterization of chiral teropyrenes, offering insights into their structural and spectroscopic properties. 

Abstract Borepin, a 7‐membered boron‐containing heterocycle, has become an emerging molecular platform for the development of new materials and optoelectronics. While electron‐deficient borepins are well‐established, reduced electron‐rich species have remained elusive. Herein we report the first isolable, crystalline borepin radical (2 a,2 b) and anion (3 a,3 b) complexes, which have been synthesized by potassium graphite (KC₈) reduction of cyclic(alkyl)(amino) carbene‐dibenzo[b,d]borepin precursors. Borepin radicals and anions have been characterized by EPR or NMR, elemental analysis, X‐ray crystallography, and cyclic voltammetry. In addition, the bonding features have been investigated computationally using density functional theory.