Chen T.,Shanghai Key Laboratory of Magnetic Resonance |
Pan L.,Shanghai Key Laboratory of Magnetic Resonance |
Loh T.A.J.,National University of Singapore |
Chua D.H.C.,National University of Singapore |
And 5 more authors.
Dalton Transactions | Year: 2014
Nitrogen-doped carbon microspheres (NCSs) were fabricated via a simple, fast and energy-saving microwave-assisted method followed by thermal treatment under an ammonia atmosphere. NCSs thermally treated at different temperatures were investigated as anode materials for lithium ion batteries (LIBs). The results show that NCSs treated at 900 °C exhibit a maximum reversible capacity of 816 mA h g-1 at a current density of 50 mA g-1 and preserve a capacity of 660 mA h g-1 after 50 cycles, and even at a high current density of 1000 mA g-1, a capacity of 255 mA h g-1 is maintained. The excellent electrochemical performance of NCSs is due to their porous structure and nitrogen-doping. The present NCSs should be promising low-cost anode materials with a high capacity and good cycle stability for LIBs. © the Partner Organisations 2014.
Huang R.-R.,Shantou University |
Huang R.-R.,Chaonan Minsheng Hospital of Shantou |
Huang R.-R.,Guangdong Key Laboratory of Medical Molecular Imaging |
Ma S.-H.,Shantou University |
And 4 more authors.
Chinese Journal of Medical Imaging Technology | Year: 2013
Diabetes mellitus can cause systematic complications associated with several systems. Central cognitive impairment and complications of diabetes have become the focus of clinical practice. Progresses on structural imaging and functional imaging of cerebral cognitive impairment in diabetes mellitus, such as MRI, MRS, SPECT, PET and fMRI, were reviewed in this article. Copyright © 2013 by the Press of Chinese Journal of Medical Imaging Technology.
Wang M.,Texas State University |
Wang C.,Texas State University |
Hao X.-Q.,Zhengzhou University |
Li X.,Soochow University of China |
And 7 more authors.
Journal of the American Chemical Society | Year: 2014
Using a series of tritopic 2,2':6',2'-terpyridine (tpy) ligands constructed on adamantane, three discrete 3D metallo-supramolecular architectures were assembled, i.e., trigonal bipyramidal, tetrahedron, and cube. The self-assembly used tritopic ligands as corner directing units and metal ions as glue units at the edge. The angles of the linkers between adamantane and tpy head play a critical role in guiding the assembled structures, which have the general formula of M3nL2n, where M denotes metal ion and L denotes ligand. All complexes were fully characterized by 1H, 13C NMR, diffusion-ordered NMR spectroscopy, ESI-MS, and traveling-wave ion mobility-mass spectrometry. The binary mixtures of LA and LC or LB and LC underwent a self-sorting process that led to the self-assembly of discrete 3D structures. The self-sorting behavior is solely based on the angles precoded within the arm of tritopic ligands. Moreover, kinetic study of preassembled cube and tetrahedron demonstrated a slow ligand exchange process toward a statistical mixture of hetero tetrahedrons with LA and LB. © 2014 American Chemical Society.
Zhou B.,CAS Qinghai Institute of Salt Lakes |
Zhou B.,Tongji University |
Sun Z.,CAS Qinghai Institute of Salt Lakes |
Yao Y.,Shanghai Key Laboratory of Magnetic Resonance |
Pan Y.,University of Saskatchewan
Physics and Chemistry of Minerals | Year: 2012
Borates consisting of diverse fundamental building blocks (FBB) formed from complex polymerization of planar triangular [Bφ 3] groups and tetrahedral [Bφ 4] groups, where φ = O and OH, provide an excellent opportunity for investigation of correlations between the NMR parameters and local structures. However, previous studies suggested that the 11B NMR parameters in borates are insensitive to local structural environments other than the B coordination number, in contrast to those documented for 29Si, 23Na and 27Al in silicates, and no correlation between 11B chemical shifts and the sum of bond valences has been established for borate minerals with hydroxyl groups or molecular water in the structures. In this study, high-resolution NMR spectra have been acquired at the ultra high field of 21 T as well as at 14 T for selected borate and borosilicate minerals, and have been used to extract high-precision NMR parameters by using combined ab initio theoretical calculations and spectral simulations. These new NMR parameters reveal subtle correlations with various structural characters, especially the effects of the 11B chemical shifts from the bridging oxygen atom(s), site symmetry, symmetry of FBB, the sum of bond valences, as well as the next-nearest-neighbor cations and hydrogen bonding. Also, these results provide new insights into the shielding mechanism for 11B in borate and borosilicate minerals. In particular, this study demonstrates that the small variation in 11B chemical shifts can still be used to probe the local structural environments and that the established correlations can be used to investigate the structural details in borates and amorphous materials. © 2012 Springer-Verlag.
Cao Z.-Y.,East China Normal University |
Zhou F.,East China Normal University |
Yu Y.-H.,Shanghai Key Laboratory of Magnetic Resonance |
Zhou J.,East China Normal University
Organic Letters | Year: 2013
It is reported for the first time that Hg(II) can catalyze the cyclopropanation of diazo reagents and alkenes, which contributes to the unprecedented highly diastereo- and enantioselective synthesis of spirocyclopropyloxindoles. © 2012 American Chemical Society.