A novel type of ruthenium oxide (RuO(2))-modified multi-walled carbon nanotube (MWNT) nanocomposite electrode (RuO(2)/MWNT) for supercapacitors has been prepared. The nanocomposites were formed by depositing Ru by magnetic-sputtering in an Ar/O(2) atmosphere onto MWNTs, which were synthesized on Ta plates by chemical vapor deposition. Cyclic voltammetry, chronopotentiometry, and electrochemical impedance measurements were applied to investigate the performance of the RuO(2)/MWNT nanocomposite electrodes. The capacitance of the MWNT electrodes in 1.0 M H(2)SO(4) is significantly increased from 0.35 to 16.94 mF cm(-2) by modification with RuO(2). The RuO(2) film on the surface of the nanotubes is composed of small crystal grains with tilted bundle-like microstructures, as observed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The results demonstrate a promising route to prepare RuO(2)/MWNT-based double-layer supercapacitors.
Iron-phthalocyanines (FePc) are functionalized at multi-walled carbon nanotubes (MWNTs) to remarkably improve the sensitivity toward hydrogen peroxide. We constructed a highly sensitive and selective glucose sensor on FePcMWNTs electrode based on the immobilization of glucose oxidase (GOD) on poly-o-aminophenol (POAP)-electropolymerized electrode surface. SEM images indicate that GOD enzymes trapped in POAP film tend to deposit primarily on the curved tips and evenly disperse along the sidewalls. The resulting GOD @ POAP/FePc-MWNTs biosensor exhibits excellent performance for glucose with a rapid response (less than 8 s), a wide linear range (up to 4.0 Â 10 À3 M), low detection limits (2.0 Â 10 À7 M with a signal-to-noise of 3), a highly reproducible response (RSD of 2.6%), and long-term stability (120 days). Such characteristics may be attributed to the catalytic activity of FePc and carbon nanotube, permselectivity of POAP film, as well as the large surface area of carbon nanotube materials.
Touch plays a crucial role in affiliative behavior and social communication. The neuropeptide oxytocin is released in response to touch and may act to facilitate the rewarding effects of social touch. However, no studies to date have determined whether oxytocin facilitates behavioral or neural responses to non-socially administered affective touch and possible differential effects of touch valence. In a functional MRI experiment using a randomized placebo-controlled, within-subject design in 40 male subjects we investigated the effects of intranasal oxytocin (24IU) on behavioral and neural responses to positive, neutral and negative valence touch administered to the arm via different types of materials at a frequency aimed to optimally stimulate C-fibers. Results showed that oxytocin significantly increased both the perceived pleasantness of touch and activation of the orbitofrontal cortex independent of touch valence. The effects of OT on touch-evoked orbitofrontal activation were also positively associated with basal oxytocin concentrations in blood. Additionally, anterior insula activity and the functional connectivity between the amygdala and right anterior insula were enhanced only in response to negative valence touch. Overall, the present study provides the first evidence that oxytocin may facilitate the rewarding effects of all types of touch, irrespective of valence.
An amount (5 wt %) of lithium tungstate (LiWO) as an additive significantly improves the cycle and rate performances of the LiNiCoMnO electrode at the cutoff voltage of 4.6 V. The 5 wt % LiWO-mixed LiNiCoMnO electrode delivers a reversible capacity of 199.2 mA h g and keeps 73.1% capacity for 200 cycles at 1 C. It retains 67.4% capacity after 200 cycles at 2 C and delivers a discharge capacity of 167.3 mA h g at 10 C, while those of the pristine electrode are only 44.7% and 87.5 mA h g, respectively. It is shown that the structure of the LiNiCoMnO cathode material is not affected by mixing LiWO. The introduced LiWO effectively restrains the LiPF and carbonate solvent decomposition by consuming PF at high cutoff voltage, forming a stable cathode/electrolyte interface film with low resistance.
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