Current-induced instability of domain walls in cylindrical nanowires

We study the current-driven domain wall (DW) motion in cylindrical nanowires using micromagnetic simulations by implementing the Landau-Lifshitz-Gilbert equation with nonlocal spin-transfer torque in a finite difference micromagnetic package. We find that in the presence of DW Gaussian wave packets (spin waves) will be generated when the charge current is applied to the system suddenly. And this effect is excluded when using the local spin-transfer torque. The existence of spin waves emission indicates that transverse domain walls can not move arbitrarily fast in cylindrical nanowires although they are free from the Walker limit. We establish an upper-velocity limit for the DW motion by analyzing the stability of Gaussian wave packets using the local spin-transfer torque. Micromagnetic simulations show that the stable region obtained by using nonlocal spin-transfer torque is smaller than that by using its local counterpart. This limitation is essential for multiple domain walls since the instability of Gaussian wave packets will break the structure of multiple domain walls.Comment: 5 pages, 6 figure

What Drives Knowledge Payment in the Knowledge Payment Platform? An Empirical Study on the Purchase Behavior in the Emerging Market

Knowledge payment has become an emerging interactive mode. This research aims to investigate the influential factors driving knowledge demanders’ knowledge payment for online knowledge in emerging markets. By integrating flow experience theory and means-end chain theory, this paper reveals the relationships between each characteristic (product characteristics, demander characteristics, and platform characteristics), and knowledge demanders’ purchase intention. Hypotheses and theoretical model with product characteristics, demander characteristics, and platform characteristics of paid knowledge were proposed. 413 effective questionnaires were collected. A structural equation modeling was constructed and AMOS was used to illustrate the original estimate value of each path and correlations between items and factors. The results show that flow experience affects path dependence and perceived cost enjoyment, path dependence influences perceived cost performance. For product characteristics, perceived substitutability negatively influences perceived cost performance and purchase intention, and perceived cost performance affects purchase intention. For demander characteristics, perceived cost enjoyment positively affects purchase intention. For platform characteristics, perceived payment risk negatively influences purchase intention, while perceived payment convenience has no significant influence on purchase intention. The findings of the research provide some strategic enlightenment for content producers, knowledge payment platform managers

High-efficiency capacitance performance from foam-like MnO2/polyaniline/carbon nanotube film hybrids

Flexible supercapacitor electrode materials based on carbon nanotube film have been successfully fabricated. Honeylike M nO2/polyaniline/Carbon nanotube fi lm hybrids (MnO2/PANI/CNTF) were manufactured via chemical oxidation polymerization and solution chemical reduction method. All electrochemical tests were carried out in a 1 M Na2SO4 electrolyte at a window voltage of -0.2- 0.8 V. The structures and morphology of the hybrids are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM). Raman spectroscopy and X-ray photoelectron spectrometer (XPS). The electrochemical performance was examined by cyclic voltammetry (CV) and galvanostatic charge/discharge (GCD). MnO2/PANI/CNTF hybrids exhibit a specifi c capacitance of 186 F/g at a current density of 1 A/g, which is much higher than of pure CNTF (20 F/g). After 1000 cycles, the capacitance was reduced by only 9 % compare to 15 % for PANI/CNTF hybrids and 19% for MnO2 /CNTF

Anti-Corrosive Properties of Alkaloids on Metals

Numerous organic inhibitors have been reported to be used for the corrosion inhibition of various metals, especially, the heterogeneous ring compounds bearing larger electronegativity atoms (i.e., N, O, S, and P), polar functional groups, and conjugated double bonds are the most effective inhibitors. Based on the concept of green chemistry, in recent years, the research of corrosion inhibitor has gradually extracted new environment-friendly corrosion inhibitor from natural animals and plants, because of its advantages in wide source, low cost, low toxicity and subsequent treatment. Alkaloids such as papaverine, strychnine, quinine, nicotine, etc., have been studied as inhibitors for metals corrosion in corrosive media. This chapter aims to review the application of alkaloids for the corrosion inhibition of metals in corrosive media, and the development trend in this field is prospected

Dexmedetomidine alleviates high glucose-induced podocyte damage by inhibiting EDA2R

Purpose: To investigate the effect and mechanism of action of dexmedetomidine (Dex) on podocyte injury. Methods: Cells were incubated with high glucose (50 mM) to induce a podocyte injury model in vitro. Cell viability, apoptosis, the expression of related protein related in podocyte injury and albumin permeability were evaluated by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT), flow cytometry, western blot and Transwell assays. Results: Dex administration enhanced HG-induced cell viability and the relative protein expression of Bcl-2, but reduced the HG-induced relative protein level of Bax and apoptosisrate in podocytes (p < 0.05). Besides, Dex incubation compensated HG-induced relative protein expressions of nephrin and podocin in podocytes but did the reverse with regard to relative protein expression of desmin and albumin permeability (p < 0.05). Moreover, Dex treatment resulted in a decrease in ectodysplasin A2 receptor (EDA2R) expression in HG-induced podocytes. The level of EDA2R was upregulated by the transfection of overexpression plasmid containing the EDA2R sequences. Overexpression of EDA2R reversed Dex-induced increase in cell viability, apoptosis, expression of nephrin, podocin and desmin, as well as albumin permeability in HG-stimulated podocytes (p < 0.05). Conclusion: Dex ameliorates HG-induced podocyte injury via inhibition of EDA2R, indicating that Dex is a potential alternative drug for the treatment of podocyte injury