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Physics of Current Filamentation in ggNMOS Devices Under ESD Condition Revisited
No full textThis paper revisits the physics of current filamentation in grounded-gate NMOS (ggNMOS) devices and presents new physical insights which were not addressed in earlier works. A clear distinction between electrical and thermal instabilities is presented. Moreover, filament dynamics under electrical and thermal instability in both silicided and silicide blocked devices is discussed while highlighting observations which contradict with established theory of current ballasting. Interplay between electrical and thermal instabilities and its dependence on the presence or absence of silicide blocking is explored further. Filament spreading in ggNMOS devices and it is dependence on silicide blocking is discussed. Finally, while using the developed physical insights, missing correlation between TLP and HBM extracted failure current of silicided ggNMOS device is explained
A mechanistic study of transfer hydrogenation catalyzed by cyclometallated ruthenium half-sandwich complexes
No full textTransfer hydrogenation of aromatic ketones catalyzed by eight cyclometallated ruthenium half-sandwich complexes, including three new complexes, was examined. The catalytic process was studied using different ratios of substrate to base and base to catalyst and using a deuterated reductant. Optimum conditions for catalysis were shown to be in the presence of higher amounts of base in refluxing isopropanol. Under these conditions, the complexes were reduced in situ to give Ru(0) nanoparticles invisible to the naked eye. The nanoparticles were characterized by TEM, DLS and XPS. The catalytic transfer hydrogenation, under conditions in which nanoparticles were generated, was found to be far greater than the transfer hydrogenation by the molecular catalyst. Complete characterization of the three new complexes, including the X-ray crystallographic characterization of these complexes was carried out. (c) 2018 Elsevier B.V. All rights reserved
Manganese-Based Nanozymes: Multienzyme Redox Activity and Effect on the Nitric Oxide Produced by Endothelial Nitric Oxide Synthase
No full textNanomaterials having enzyme-like activity (nanozymes) make them suitable candidates for various biomedical applications. In this study, we demonstrate the morphology-dependent enzyme mimetic activity of Mn3O4 nanoparticles. It is found that Mn3O4 nanoparticles mimic the functions of all three cellular antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). Interestingly, the nanozyme activity of Mn3O4 depends on various factors including size, morphology, surface area, and the redox properties of the metal ions. The Mn3O4 nanoflowers exhibited remarkably high activity in all three enzyme systems and the order of multienzyme activity of different morphologies was: flowers >> flakes > hexagonal plates approximate to polyhedrons approximate to cubes. Interestingly, all five nanoforms are taken up by the mammalian cells and were found to be biocompatible, with very low cytotoxicity. The activity of the most active nanoflowers was studied in primary human umbilical vein endothelial cells (HUVEC) and human pulmonary microvascular endothelial cells (hPMEC) and it was found that Mn3O4 does not reduce the level of nitric oxide (NO). This is in contrast to the effect of some of the Mn-porphyrin-based SOD mimetics, which are known to scavenge NO in endothelial cells
Assessing the structure and stability of transmembrane oligomeric intermediates of an alpha-helical toxin
No full textEffect of Surface Roughness on Bandwidth of a High Frequency Multiple Beam Klystron
No full textEffect of surface roughness on the bandwidth of a high frequency multiple beam klystron (MBK) cavity circuit is investigated. Surface roughness reduces the surface conductivity of the base material which in turn reduces the unloaded quality factor of the cavity and increases the bandwidth of the cavity. First, effective conductivity is calculated analytically for a given surface roughness, and then it is related to the quality factor and 3dB bandwidth of the cavity. Analytical results are compared with those obtained from 3D simulations
Rainfall seasonality on the Indian subcontinent during the Cretaceous greenhouse (vol 8, 8482, 2018)
No full textSynthesis, Structure, Bonding, and Reactivity of Metal Complexes Comprising Diborane(4) and Diborene(2): {Cp*Mo(CO)(2)}(2){mu-eta(2):eta(2)-B2H4}] and {Cp*M(CO)(2)}(2)B2H2M(CO)(4)], M=Mo,W
No full textThe reaction of (Cp*Mo)(2)(mu-Cl)(2)B2H6] (1) with CO at room temperature led to the formation of the highly fluxional species {Cp*Mo(CO)(2)}(2){mu-eta(2):eta(2)-B2H4}] (2). Compound 2, to the best of our knowledge, is the first example of a bimetallic diborane(4) conforming to a singly bridged C-s structure. Theoretical studies show that 2 mimics the Cotton dimolybdenum-alkyne complex {CpMo(CO)(2)}(2)C2H2]. In an attempt to replace two hydrogen atoms of diborane(4) in 2 with a 2e W(CO)(4)] fragment, {Cp*Mo(CO)(2)}(2) B2H2W(CO)(4)] (3) was isolated upon treatment with W(CO)(5).thf]. Compound 3 shows the intriguing presence of B2H2] with a short B-B length of 1.624(4) angstrom. We isolated the tungsten analogues of 3, {Cp*W(CO)(2)}(2)B2H2W(CO)(4)] (4) and {Cp*W(CO)(2)}(2)B2H2Mo(CO)(4)] (5), which provided direct proof of the existence of the tungsten analogue of 2
Universal conductance fluctuations and direct observation of crossover of symmetry classes in topological insulators
No full textA key feature of topological insulators (TIs) is symplectic symmetry of the Hamiltonian which changes to unitary when time-reversal symmetry is lifted and a topological phase transition occurs. However, such a crossover has yet to be explicitly observed by directly probing the symmetry class of the Hamiltonian. In this Rapid Communication, we have probed the symmetry class of topological insulators by measuring the mesoscopic conductance fluctuations in the TI Bi1.6Sb0.4Te2Se, which shows an exact factor of 2 reduction on application of a magnetic field due to a crossover from symplectic to unitary symmetry classes. The reduction provides an unambiguous proof that the fluctuations arise from the universal conductance fluctuations (UCFs), due to quantum interference, and persists from T similar to 22 mK to 4.2 K. We have also compared the phase breaking length l(phi) extracted from both magnetoconductance and UCFs which agree well within a factor of 2 in the entire temperature and gate voltage range. Our experiment confirms UCF as the major source of fluctuations in mesoscopic disordered topological insulators, and the intrinsic preservation of time-reversal symmetry in these systems
Surface Ocean Enstrophy, Kinetic Energy Fluxes, and Spectra From Satellite Altimetry
No full textSpectra and fluxes of enstrophy and kinetic energy (KE) are estimated in different parts of the midlatitudinal oceans using geostrophic currents derived from altimetry data. The presence of a strong inverse flux of surface KE is confirmed at scales larger than approximately 200 km, whereas a robust enstrophy cascading regime, accompanied by an approximate k(-3) KE spectrum, is observed from about 200 to 100 km. The character of fluxes and spectra is shown to compare favorably with those from a comprehensive Earth system model. In addition, as gridded altimeter data are affected by smoothening and interpolation, the qualitative robustness of the results is verified by sensitivity experiments using space and time-filtered output from the Earth system model. Given the rotational character of the flow, this large-scale inverse KE and smaller-scale forward enstrophy transfer scenario is consistent with expectations from three-dimensional rapidly rotating and strongly stratified turbulence studies as well as detailed analyses of spectra and fluxes in the upper-level midlatitude troposphere. In further accord with results from the atmosphere, decomposing the currents into stationary and eddy components (demarcated here by variability greater and less than 100 days, respectively), it is seen that, in addition to the eddy-eddy contribution, the stationary-eddy and stationary-stationary fluxes play a significant role in the inverse (forward) flux of KE (enstrophy). Thus, it is quite possible that, from about 200 to 100 km, the altimeter is capturing the rotationally dominated portion of a surface oceanic counterpart of the upper tropospheric Nastrom-Gage spectrum