2,776 research outputs found
Investigation of ultra-thin Al₂O₃ film as Cu diffusion barrier on low-k (k=2.5) dielectrics
Ultrathin Al(2)O(3) films were deposited by PEALD as Cu diffusion barrier on low-k (k=2.5) material. The thermal stability and electrical properties of the Cu/low k system with Al(2)O(3) layers with different thickness were studied after annealing. The AES, TEM and EDX results revealed that the ultrathin Al(2)O(3) films are thermally stable and have excellent Cu diffusion barrier performance. The electrical measurements of dielectric breakdown and TDDB tests further confirmed that the ultrathin Al(2)O(3) film is a potential Cu diffusion barrier in the Cu/low-k interconnects system
A Wide-Angle Scanning Planar Phased Array with Pattern Reconfigurable Magnetic Current Element
Simulation Study on neutrino nucleus cross section measurement in Segmented Detector at Spallation Neutron Source
Knowledge of - differential cross sections
for energy below several tens of MeV scale is believed to be crucial in
understanding Supernova physics. In a segmented detector at Spallation Neutrino
Source, energy reconstructed from the electron range measurement is
strongly affected because of both multiple scattering and electromagnetic
showers occurring along the electron passage in target materials. In order to
estimate the effect, a simulation study has been performed with a cube block
model assuming a perfect tracking precision. The distortion of energy spectrum
is observed to be proportional to the atomic number of target material.
Feasibility of unfolding the distorted energy spectrum is studied for
both Fe and Pb cases. Evaluation of statistical accuracy attainable is
therefore provided for a segmented detector.Comment: 6 pages, 6 figures, submitted to Chinese Physics
Effect of magnetic Fe3O4 nanoparticles with 2-methoxyestradiol on the cell-cycle progression and apoptosis of myelodysplastic syndrome cells
This study aims to evaluate the potential benefit of combination therapy of 2-methoxyestradiol (2ME) and magnetic nanoparticles of Fe3O4 (MNPs-Fe3O4) on myelodysplastic syndrome (MDS) SKM-1 cells and its underlying mechanisms. The effect of the unique properties of tetraheptylammonium-capped MNPs-Fe3O4 with 2ME on cytotoxicity was tested by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Cell-cycle distribution and apoptosis were assessed by flow cytometry. The expression of cell-cycle marker protein was measured by Western blotting. Growth inhibition rate of SKM-1 cells treated with the 2ME-loaded MNPs-Fe3O4 was enhanced when compared with 2ME alone. 2ME led to an increase of caspase-3 expression, followed by apoptosis, which was significantly increased when combined with an MNPs-Fe3O4 carrier. Moreover, the copolymer of 2ME with MNPs- Fe3O4 blocked a nearly two-fold increase in SKM-1 cells located in G2/M phase than in 2ME alone, which may be associated with an accompanying increase of p21 as well as a decrease in cyclin B1 and cdc2 expression, but there was no obvious difference between the MNPs-Fe3O4 and control group. These findings suggest that the unique properties of MNPs-Fe3O4 as a carrier for 2ME, a new anticancer agent currently in clinical trials, may be a logical strategy to enhance the therapeutic activity of MDS
Nanotube ferroelectric tunnel junctions with giant tunneling electroresistance ratio
Low-dimensional ferroelectric tunnel junctions are appealing for the
realization of nanoscale nonvolatile memory devices due to their inherent
advantage of device miniaturization. Those based on current mechanisms still
have restrictions including low tunneling electroresistance (TER) effects and
complex heterostructures. Here, we introduce an entirely new TER mechanism to
construct the nanotube ferroelectric tunnel junction with ferroelectric
nanotubes as the tunneling region. When rolling a ferroelectric monolayer into
a nanotube, due to the coexistence of its intrinsic ferroelectric polarization
with the flexoelectric polarization induced by bending, there occurs
metal-insulator transition depending on radiative polarization states. For the
pristine monolayer, its out-of-plane polarization is tunable by an in-plane
electric field, the conducting states of the ferroelectric nanotube can thus be
tuned between metallic and insulating via axial electric means. Using
{\alpha}-In2Se3 as an example, our first-principles density functional theory
calculations and nonequilibrium Green's function formalism confirm the
feasibility of the TER mechanism and indicate an ultrahigh TER ratio exceeding
9.9*10^10% of the proposed nanotube ferroelectric tunnel junctions. Our
findings provide a promising approach based on simple homogeneous structures
for high density ferroelectric microelectronic devices with excellent ON/OFF
performance.Comment: 15 pages, 5 figure
Advances in bioorganic molecules inspired degradation and surface modifications on Mg and its alloys
Mg alloys possess biodegradability, suitable mechanical properties, and biocompatibility, which make them possible to be used as biodegradable implants. However, the uncontrollable degradation of Mg alloys limits their general applications. In addition to the factors from the metallic materials themselves, like alloy compositions, heat treatment process and microstructure, some external factors, relating to the test/service environment, also affect the degradation rate of Mg alloys, such as inorganic salts, bioorganic small molecules, bioorganic macromolecules. The influence of bioorganic molecules on Mg corrosion and its protection has attracted more and more attentions. In this work, the cutting-edge advances in the influence of bioorganic molecules (i.e., protein, glucose, amino acids, vitamins and polypeptide) and their coupling effect on Mg degradation and the formation of protection coatings were reviewed. The research orientations of biomedical Mg alloys in exploring degradation mechanisms in vitro were proposed, and the impact of bioorganic molecules on the protective approaches were also explored
Catalytically efficient Ni-NiOₓ-Y₂O₃ interface for medium temperature water-gas shift reaction
The metal-support interfaces between metals and oxide supports have long been studied in catalytic applications, thanks to their significance in structural stability and efficient catalytic activity. The metal-rare earth oxide interface is particularly interesting because these early transition cations have high electrophilicity, and therefore good binding strength with Lewis basic molecules, such as H2O. Based on this feature, here we design a highly efficient composite Ni-Y2O3 catalyst, which forms abundant active Ni-NiOx-Y2O3 interfaces under the water-gas shift (WGS) reaction condition, achieving 140.6 μmolCO gcat-1 s-1 rate at 300 °C, which is the highest activity for Ni-based catalysts. A combination of theory and ex/in situ experimental study suggests that Y2O3 helps H2O dissociation at the Ni-NiOx-Y2O3 interfaces, promoting this rate limiting step in the WGS reaction. Construction of such new interfacial structure for molecules activation holds great promise in many catalytic systems
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