248 research outputs found
1-(4-Bromo-2-fluoroÂbenzÂyl)pyridinium bisÂ(2-thioxo-1,3-dithiole-4,5-dithiolÂato)nickelate(III)
The title compound, (C12H10BrFN)[Ni(C3S5)2], is an ion-pair complex consisting of N-(2-fluoro-4-bromoÂbenzÂyl)pyridinium cations and [Ni(dmit)2]− anions (dmit = 2-thioxo-1,3-dithiole-4,5-dithiolÂate). In the anion, the NiIII ion exhibits a square-planar coordination involving four S atoms from two dmit ligands. In the crystal structure, weak S⋯S [3.474 (3), 3.478 (3) and 3.547 (3) Å] and S⋯π [S⋯centroid distances = 3.360 (3), 3.378 (2), 3.537 (2) and 3.681 (3) Å] interÂactions and C—H⋯F hydrogen bonds lead to a three-dimensional supraÂmolecular network
TriaquaÂbis(1H-imidazole)bisÂ[μ2-2-(oxaloÂamino)benzoato(3−)]dicopper(II)calcium(II) heptaÂhydrate
In the title heterotrinuclear coordination compound, [CaCu2(C9H4NO5)2(C3H4N2)2(H2O)3]·7H2O, the Ca2+ cation is in a pentaÂgonal–bipyramidal geometry and bridges two (1H-imidazole)[2-(oxaloamino)benzoato(3−)]copper(II) units in its equatorial plane. Each CuII atom has a normal square-planar geometry. The molÂecule has approximate local (non-crystallographic) mirror symmetry and 23 classical hydrogen bonds are found in the crystal structure
Correlation-induced symmetry-broken states in large-angle twisted bilayer graphene on MoS2
Strongly correlated states are commonly emerged in twisted bilayer graphene
(TBG) with magic-angle, where the electron-electron (e-e) interaction U becomes
prominent relative to the small bandwidth W of the nearly flat band. However,
the stringent requirement of this magic angle makes the sample preparation and
the further application facing great challenges. Here, using scanning tunneling
microscopy (STM) and spectroscopy (STS), we demonstrate that the
correlation-induced symmetry-broken states can also be achieved in a 3.45{\deg}
TBG, via engineering this non-magic-angle TBG into regimes of U/W > 1. We
enhance the e-e interaction through controlling the microscopic dielectric
environment by using a MoS2 substrate. Simultaneously, the bandwidth of the
low-energy van Hove singularity (VHS) peak is reduced by enhancing the
interlayer coupling via STM tip modulation. When partially filled, the VHS peak
exhibits a giant splitting into two states flanked the Fermi level and shows a
symmetry-broken LDOS distribution with a stripy charge order, which confirms
the existence of strong correlation effect in our 3.45{\deg} TBG. Our result
paves the way for the study and application of the correlation physics in TBGs
with a wider range of twist angle
Interfaces Between Cathode and Electrolyte in Solid State Lithium Batteries: Challenges and Perspectives
Solid state lithium batteries are widely accepted as promising candidates for next generation of various energy storage devices with the probability to realize improved energy density and superior safety performances. However, the interface between electrode and solid electrolyte remain a key issue that hinders practical development of solid state lithium batteries. In this review, we specifically focus on the interface between solid electrolytes and prevailing cathodes. The basic principles of interface layer formation are summarized and three kinds of interface layers can be categorized. For typical solid state lithium batteries, a most common and daunting challenge is to achieve and sustain intimate solid-solid contact. Meanwhile, different specific issues occur on various types of solid electrolytes, depending on the intrinsic properties of adjacent solid components. Our discussion mostly involves following electrolytes, including solid polymer electrolyte, inorganic solid oxide and sulfide electrolytes as well as composite electrolytes. The effective strategies to overcome the interface instabilities are also summarized. In order to clarify interfacial behaviors fundamentally, advanced characterization techniques with time, and atomic-scale resolution are required to gain more insights from different perspectives. And recent progresses achieved from advanced characterization are also reviewed here. We highlight that the cooperative characterization of diverse advanced characterization techniques is necessary to gain the final clarification of interface behavior, and stress that the combination of diverse interfacial modification strategies is required to build up decent cathode-electrolyte interface for superior solid state lithium batteries
Circ_0040039 May Aggravate Intervertebral Disk Degeneration by Regulating the MiR-874-3p-ESR1 Pathway
The functional alteration of nucleus pulposus cells (NPCs) exerts a crucial role in the occurrence and progression of intervertebral disk degeneration (IDD). Circular RNAs and microRNAs (miRs) are critical regulators of NPC metabolic processes such as growth and apoptosis. In this study, bioinformatics tools, encompassing Gene Ontology pathway and Venn diagrams analysis, and protein–protein interaction (PPI) network construction were used to identify functional molecules related to IDD. PPI network unveiled that ESR1 was one of the most critical genes in IDD. Then, a key IDD-related circ_0040039-miR-874-3p-ESR1 interaction network was predicted and constructed. Circ_0040039 promoted miR-874-3p and repressed ESR1 expression, and miR-874-3p repressed ESR1 expression in NPCs, suggesting ESR1 might be a direct target of miR-874-3p. Functionally, circ_0040039 could enhance NPC apoptosis and inhibit NPC growth, revealing that circ_0040039 might aggravate IDD by stabilizing miR-874-3p and further upregulating the miR-874-3p-ESR1 pathway. This signaling pathway might provide a novel therapeutic strategy and targets for the diagnosis and therapy of IDD-related diseases
Ultrafast field-driven monochromatic photoemission from carbon nanotubes
Ultrafast electron pulses, combined with laser-pump and electron-probe
technologies, allow for various forms of ultrafast microscopy and spectroscopy
to elucidate otherwise challenging to observe physical and chemical
transitions. However, the pursuit of simultaneous ultimate spatial and temporal
resolution has been largely subdued by the low monochromaticity of the electron
pulses and their poor phase synchronization to the optical excitation pulses.
State-of-the-art photon-driven sources have good monochromaticity but poor
phase synchronization. In contrast, field-driven photoemission has much higher
light phase synchronization, due to the intrinsic sub-cycle emission dynamics,
but poor monochromaticity. Such sources suffer from larger electron energy
spreads (3 - 100 eV) attributed to the relatively low field enhancement of the
conventional metal tips which necessitates long pump wavelengths (> 800 nm) in
order to gain sufficient ponderomotive potential to access the field-driven
regime. In this work, field-driven photoemission from ~1 nm radius carbon
nanotubes excited by a femtosecond laser at a short wavelength of 410 nm has
been realized. The energy spread of field-driven electrons is effectively
compressed to 0.25 eV outperforming all conventional ultrafast electron
sources. Our new nanotube-based ultrafast electron source opens exciting
prospects for attosecond imaging and emerging light-wave electronics
Tunable Interband Transitions in Twisted h-BN/Graphene Heterostructures
In twisted h-BN/graphene heterostructures, the complex electronic properties
of the fast-traveling electron gas in graphene are usually considered to be
fully revealed. However, the randomly twisted heterostructures may also have
unexpected transition behaviors, which may influence the device performance.
Here, we study the twist angle-dependent coupling effects of h-BN/graphene
heterostructures using monochromatic electron energy loss spectroscopy. We find
that the moir\'e potentials alter the band structure of graphene, resulting in
a redshift of the intralayer transition at the M-point, which becomes more
pronounced up to 0.25 eV with increasing twist angle. Furthermore, the twisting
of the Brillouin zone of h-BN relative to the graphene M-point leads to tunable
vertical transition energies in the range of 5.1-5.6 eV. Our findings indicate
that twist-coupling effects of van der Waals heterostructures should be
carefully considered in device fabrications, and the continuously tunable
interband transitions through the twist angle can serve as a new degree of
freedom to design optoelectrical devices
- …