Hemin-based conjugated effect synthesis of Fe–N/CNT catalysts for enhanced oxygen reduction

Fe/N-codoped carbon nanotubes fabricated through the π–π stacking effect and olefin oxidation polymerization-induced hemin assembly on PPy shows a potential application for ORR.

Long-range Stacking Effects of Nucleobases in Charge Transfer

Base-stacked structure is an important feature of DNA molecules. Previous studies on the stacking effect concerning DNA-mediated hole transfer have revealed the influence of neighboring bases on onsite energies. But the neighboring base effect acts only in a short-distance. Besides it, a long-range (longer than three base pairs) stacking effect called squeezing effect in this paper has not yet been reported. Such a squeezing effect causes the bases near the middle of a sequence consisting of same type base pairs have lower onsite energies than the bases near the terminals. We predict it by H ̈uckelanalysis in an unconventional way and confirmed it by semiempirical calculations combinated with molecular dynamics simulations. The results suggest that in order to obtain a reasonable onsite energy map when study charge transfer on DNA, the stacking effects should be considered in a long-distance as possible. The consideration of squeezing effect also provides a new suggestion on the driving force of fluctuation-assisted DNA charge transfer. The method used to calculate the onsite energies in abase stack can be generalized to other π-stacked systems.<br><br>

Long-range Stacking Effects of Nucleobases in Charge Transfer

Base-stacked structure is an important feature of DNA molecules. Previous studies on the stacking effect concerning DNA-mediated hole transfer have revealed the influence of neighboring bases on onsite energies. But the neighboring base effect acts only in a short-distance. Besides it, a long-range (longer than three base pairs) stacking effect called squeezing effect in this paper has not yet been reported. Such a squeezing effect causes the bases near the middle of a sequence consisting of same type base pairs have lower onsite energies than the bases near the terminals. We predict it by H ̈uckelanalysis in an unconventional way and confirmed it by semiempirical calculations combinated with molecular dynamics simulations. The results suggest that in order to obtain a reasonable onsite energy map when study charge transfer on DNA, the stacking effects should be considered in a long-distance as possible. The consideration of squeezing effect also provides a new suggestion on the driving force of fluctuation-assisted DNA charge transfer. The method used to calculate the onsite energies in abase stack can be generalized to other π-stacked systems.<br><br>

A Dual Port 8T SRAM Cell Using FinFET & CMOS Logic for Leakage Reduction and Enhanced Read & Write Stability

Static Random-Access Memory cells with ultralow leakage and superior stability are the primary choice of embedded memories in contemporary smart devices. This paper presents a novel 8T SRAM cell with reduced leakage and improved stability. The proposed SRAM cell uses a stacking effect to reduce leakage and transmission gate as an access transistor to enhance stability. The performance of the proposed 8T SRAM cell with a stacked transistor has been analyzed based on the power consumption and static noise margin (RSNM, HSNM, and WSNM). The power consumption in the case of FinFET based 8T cell is found to be 572 pW at 22 nm technology node, which is reduced by a factor nearly as compared to that of CMOS based 8T cell. Further, in the case of FinFET based novel 8T SRAM cell at 22 nm technology node, the power consumption is found to be reduced by a factor of as compared to that of FinFET based conventional 6T SRAM cell. WSNM, HSNM, and RSNM of the 8T SRAM cell designed with FinFET logic are observed as 240 mV, 370 mV, and 120 mV respectively at 0.9 V supply voltage. When comparing with conventional 6T FinFET Cell, the proposed Cell shows 20%, 5.11%, and 7% improvement in WSNM, HSNM, and RSNM, respectively. The sensitivity of SNM with temperature variation is also analyzed and reported. Further, the results obtained confirm the robustness of the proposed SRAM cells as compared to several recent works.

Silsesquioxane-Polythiophene Hybrid Copolymer as an Efficient Modifier for Single-Walled Carbon Nanotubes

One silsesquioxane-polythiophene hybrid copolymer, with combined star-like structure and intramolecular heterogeneity, was synthesized and sufficiently characterized via various methods, including FTIR, NMR, and SEC measurements. According to the exploration and characterization results, it was much more efficient at modifying SWNTs than its linear analogs in aqueous solution. The hydrophobic silsesquioxane core and PEDOT chains could locally anchor to the surface of the nanotubes, while the soluble flexible copolymer chains extended into the solution and rigid conjugated chains provided some π-π stacking effect to enhance adhesive force with the conjugated structure of the carbon nanotube, imparting steric stabilization to nanotube dispersion. The noncovalent interaction with SWNTs and solubility in aqueous solution improved the electrochemical characteristics of the modified-SWNT composite and availed for the preparation of a flexible and transparent electroactive film. Accordingly, this kind of silsesquioxane-polythiophene hybrid copolymer will be forwarded to apply to the assembling of flexible optoelectronic devices.