Krabbeparrott5180

However, at high frequency the presence of a weak hump-like structure almost at the center of above two peaks validate the role of interface traps. DLTS studies show that traps at the interface of HgTe nanocrystals/TiO2 acts as recombination centers having activation energies of 0.27, 0.4 and 0.45 eV with corresponding trap densities of 1.4×10^10, 1.9×10^11 and 1.5×10^11 〖cm〗^(-3) and estimated capture cross-sections of 6.3×10^(-14), 7.5×10^(-17) and 3.7×10^(-14) 〖cm〗^2, respectively. In this work, DLTS has revealed the existence of interface trap states and the frequency dependent capacitance measurements corroborate the effect of charge storage on the heterostructures built from these nanocrystals that helps in the development of futuristic devices.Objective In this paper, we report on the development of an easy-to-fabricate three-dimensional Micro-Electrode Array (3D-MEA) specifically designed for brain-on-a-dish applications. Approach The proposed device consists of pillar-shaped gold microelectrodes realized by electroplating directly on top of a standard MEA, making this approach highly versatile and convenient for batch fabrication. Moreover, with this simple technique, it is possible to obtain electrodes with a height of more than 100 µm onto different kind of substrates, ranging from glass to flexible plastic ones. Main results This novel 3D-MEA structure has been validated with acute brain slices, successfully recording both epileptiform-like discharges (upon the administration of 4-AP), and electrically-evoked neuronal activity. The preliminary validation showed a substantial improvement in the signals amplitude with respect to both commercial and custom planar electrodes thanks to a better coupling offered by the peculiar shape of the three-dimensional electrodes. Significance Beside the versatility of the fabrication approach, which allows to obtain 3D MEA devices onto both rigid and flexible substrates, the reported validation showed how the pillar approach can outperform standard planar MEA recordings in terms of signal amplitude. Moreover, thanks to the possibility of obtaining multi-level 3D structures within the same device, the proposed fabrication technique offers an interesting and flexible approach for the development of a new family of electrophysiological tools for 3D in vitro electrophysiology, in particular for acute brain slices and 3D neuronal cultures for brain-on-a-dish applications.As a new type of colloidal nanocrystals, perovskite quantum dots (QDs) have received widespread attention. Water and oxygen in the air can affect the luminous efficiency of quantum dots, which can degrade the surface of QDs and affect their luminescence efficiency. Herein we discuss the synthesis of high-quality QDs using an uncomplicated coating method by which an ultrathin epitaxial Al self-passivation layer bearing homogeneous ligands can be coated on the QDs. The core/shell perovskite QDs maintain high luminescence efficiency and photostability. The CsPbBr3/2ZnS/Al QDs were only attenuated by 10% after 14 h of exposure to LED light. The temperature-dependent photoluminescence properties of the all-inorganic perovskite QDs, such as the PL intensity, emission peak position, and the full width at half maximum (FWHM), were investigated. The results indicated that the activation energy of QDs increases with the increase of the number of ZnS shell layers, its stability increases significantly. The introduction of Al does not change the luminescence mechanism of QDs. Finally, we have made flexible light-emitting device with CsPbBr3/2ZnS/Al QDs.Rechargeable aqueous zinc-ion batteries (ZIBs) have attracted significant attention due to the distinguishing characteristics of zinc metal, including its low price, abundance in earth, safety and high theoretical specific capacity of 820 mAh g-1. Manganese dioxide (MnO2) is a promising cathode for ZIBs due to high theoretical specific capacity, high discharge voltage plateau, cost-effectiveness and nontoxicity. However, the low electronic conductivity and volumetric changes during electrochemical cycling hinder its practical utilization. Herein, we demonstrate a polyacrylic acid (PAA)-assisted assembling strategy to fabricate freestanding and flexible MnO2/carbon nanotube/PAA (MnO2/CNT/PAA) cathodes for ZIBs. selleck chemicals PAA plays an important role in providing excellent mechanical properties to the free-standing electrode. Moreover, the presence of CNT forms an electron conductive network, and the porous structure of MnO2/CNT/PAA electrode accommodates the volumetric variations of MnO2 during charge/discharge cycling. The as-fabricated quasi-solid-state Zn-MnO2/CNT/PAA battery delivers a high charge storage capacity of 302 mAh g-1 at 0.3 A g-1 and retains 82% of the initial capacity after 1000 charge/discharge cycles at 1.5 A g-1. The calculated volumetric energy density of Zn-MnO2/CNT/PAA battery is 8.5 mW h cm-3 (with a thickness of 0.08 cm), which is significantly higher than the reported alkali-ion batteries (1.3 mW h cm-3) and comparable to supercapacitors (6.8 mW h cm-3) and Ni-Zn batteries (7.76 mW h cm-3). The current work demonstrates that free-standing MnO2/CNT/PAA composite is a promising cathode for ZIBs.Semiconductor microcavities can greatly enhance the light-emitting of embedded quantum dots (QDs). Here, a new route toward the microcavity-QD system by fabricating microcavities followed by growing ordered QDs on patterned microresonator is proposed, which keeps QDs from being etched. Self-assembled Ge QDs prefer to form at the rims of Si microrings or microdisks. The Ge QDs on the pit- or groove-patterned microring resonator (MRR) show better size uniformity and position accuracy. These features are explained by the evolutions of surface morphology and surface chemical potential distribution. link2 Sharp photoluminescence peaks in the telecommunication band with the quality factors in the range of 450-850 from groove-patterned MRR are observed at 295 K due to efficient overlap between Ge QDs and resonant modes. Our schemes shed light on the exactly site-controlled growth of QDs on micro- and nano-structures, which further facilitates the investigation of light-matter interactions.The temperature-dependent transversely isotropic elastic properties of multi-walled boron nitride nanotubes (MWBNNTs) were determined using molecular dynamics simulations with a three-body Tersoff potential force field. These elastic properties were calculated by applying the four different loading conditions on MWBNNTs uniaxial tension, torsional moment, in-plane biaxial tension and in-plane shear. The effect of chirality, number of layers and aspect ratio (AR) were taken into consideration. The results reveal that the elastic constants of MWBNNTs decrease as their number of layers increase. The elastic moduli of MWBNNTs do not depend on the AR but are function of chirality. Furthermore, the effect of temperature on the transversely isotropic elastic constants of MWBNNTs was studied. The higher temperature considerably affects the mechanical properties of MWBNNTs. For instance, the reduction in the values of axial Young's, longitudinal shear, plane-strain bulk and in-plane shear moduli of MWBNNTs was found to be by approximately 10% due to the increase in temperature. The results reveal that the mechanical properties and failure behavior of MWBNNTs significantly depend on the number of layers, chirality and temperature. The finding of this work can be utilized for engineering the MWBNNT-based advanced nanocomposite structures for specific application under thermal environment.Unconventional lattice fermions with high degeneracies that are not Weyl or Dirac fermions have attracted increased attention in recent years. In this paper, we consider pseudospin-1 Maxwell fermions and the $(2+1)$-dimensional parity anomaly, which are not constrained by the fermion doubling theorem. We derive the Hall conductivity of a single Maxwell fermion and explain how each Maxwell fermion has a quantized Hall conductance of $e^2/h$. Parity is spontaneously broken in the effective theory of lattice Maxwell fermions interacting with an (auxiliary) U(1) gauge field, leading to an effective anomaly-induced Chern--Simons theory. An interesting observation about the parity anomaly is that the lattice Maxwell fermions are not constrained by the fermion doubling theorem, so a single Maxwell fermion can exist in a lattice. In addition, our work considers the quantum anomaly in odd-dimensional spinor space.The concept of realization of Weyl points close to Fermi level in materials with broken time-reversal symmetry has significant theoretical and technological ramifications. Here, we review on the investigation of magneto-transport measurements in single crystals of magnetic Weyl semimetal Co3Sn2S2. We see a turn-on like behaviour followed by saturation in resistivity under magnetic field in the low temperature region which allocates to the topological surface states. A non-saturating magnetoresistance, linear at high fields, is observed at low temperatures where applied magnetic field is transverse to the current direction. The linear negative magnetoresistance at low magnetic fields (B less then 0.1T) provides evidence for time reversal symmetry breaking in Co3Sn2S2. Chiral anomaly in Weyl metallic state in Co3Sn2S2 is confirmed from the breakdown of Ohm's law in the electronic transport. Shubnikov de Haas (SdH) oscillation measurement has unveiled the multiple sub-bands on the Fermi surface that corresponds to a non-trivial Berry phase. link3 The non-linear behaviour in Hall resistivity validates the existence of two type of charge carriers with equal electron and hole densities. Strong temperature dependence of carrier mobilities reflects the systematic violation of Kohler's rule in Co3Sn2S2. Our findings open avenues to study kagome-lattice based magnetic Weyl semimetals that unfurl the basic topological aspects leading to significant ramification for spintronics.The remarkable tribological attributes of the Gecko feet have grown much interest in the field of biomimetic tribology over the past two decades. It has been shown, that the complexity of friction and adhesion phenomena made it difficult to transfer these exceptional properties into fully functional smart, dry, micro patterned adhesives. The latter, combined with the relative lack of literature on computational oriented studies on these phenomena, is the motive of the current work. Here, a 2D time dependent finite element model of friction and adhesion attributed contact of polydimethysiloxane (PDMS) micro flaps with a smooth SiO2 spherical surface is presented. The model is tested through simulations concerning changes in the disc curvature, the flap density, as well as different disc mounting heights, representing the effect of preload. Furthermore, the effect of tribological parameters of adhesion and friction coefficient is discussed. Finally, the effect of the use of two hyperelastic material models was examined.Doping with exotic elements has become a general effective method for the synthesis of efficient nitrogen fixation photocatalyst. Wide bandgap semiconductors, thermodynamically, could be potential photocatalysts for nitrogen reduction reaction (NRR). In this study, we report an active photocatalyst of Fe doped SrWO4 from a facile solvothermal method. The band structure of SrWO4 can be regulated by varying the Fe doping concentration, and still fulfill the thermodynamical requirements of photocatalytic NRR. The doped samples also exhibit strong absorbance in visible light region. At optimal doping concentration, the photocatalyst shows significant enhancement of the ammonia production rate in ultrapure water compared to the pristine SrWO4. The results photoelectrochemical measurements and the photoluminescence spectra indicate that the enhancement of the performance is ascribed to the balanced defect states and optimized charge transfer. The present study opens a route toward the development of active photocatalysts with preferable thermodynamics for the fixation of atmospheric N2 employing solar light.