Ample Channels Research Articles

Self-standing Ni–Cu–Ti/NCNTs electrocatalyst with porous structure for hydrogen evolution reaction

Self-standing Ni–Cu–Ti/NCNTs electrocatalyst with porous structure for hydrogen evolution reaction

Quinone carbonyl activation for in situ constructing kinetic-boosted zincophilic polymer interphase toward high performance Zn metal anode

Quinone carbonyl activation for in situ constructing kinetic-boosted zincophilic polymer interphase toward high performance Zn metal anode

An integrated approach for reservoirs characterization: A case study from the Barreirinhas basin in Maranhão, Brazil

Seismic attributes have made an important contribution to the interpretation of seismic data, ranging from regional mapping to reservoirs characterization. The present study describes an oil reservoir based on its seismic attributes, in an anticline formed by fold systems, related to thrust-type faults in the lower portion of the continental slope of the Barreirinhas Basin in Maranhão, Brazil. Instantaneous, geometric, and coherence attributes permit the identification of hydrocarbons, lithology, continuities/discontinuities, faults, and the depositional environment in the study basin. The use of the coherence attribute permitted the identification of characteristic deltaic fans in the shallow marine environment, which filled ample channels recognized by their instantaneous attributes, overlaid, in turn, by distributary channels observed in the geometric attributes, which were filled by successive sandy sedimentary successions that gave rise to sandstones with characteristics of good reservoirs and high velocity wave. Finally, these seismic attributes associated with the geophysical-geological seismic interpretation, permitted the identification of additional leads with promising characteristics that should be targeted in a future research.

Hollow Fe/Ni–CoTe@NCFs nanoarchitecture derived from MOF@MOF as high-efficiency electrocatalysts for boosting oxygen evolution reaction

To improve the oxygen evolution reaction (OER) catalytic efficiency of non-noble-metal-based catalysts, researchers have made great endeavors to adjust the compositions, morphologies and configuration of material. In this work, a dual-metal-organic frameworks (MOFs)-assisted fabrication hierarchical and hollow N-doped carbon nanoframes (NCFs) decorated with Fe/Ni-codoped CoTe nanocomposite catalyst (Fe/Ni–[email protected]) is reported. Starting from MOF-in-MOF composite precursors, the design and fabrication of Fe/Ni–CoTe by the strategies: i.e, hydrothermal precipitation, chemical etching and low-temperature tellurization, and high-temperature pyrolysis steps. Newly designed catalyst (Fe/Ni–[email protected]) performs superior OER catalytic activity to afford 10 mA cm−2 at the overpotential of 287 mV with a small Tafel slope of 52.3 mV dec−1. The frame-like hollow core-shell nanostructures with ample channels into the internal volume and high double-layer capacitance provide the large catalytic active surface area and increase more actives sites. The cooperative effects between alloy and metal telluride, as well as hollow carbon shell promote the activity of OER. Therefore, this study offers a catalyst with great potential for OER and provides the possibility for the application of transition metal tellurides in electrocatalysis.

Rational synthesis of uniform yolk–shell Ni–Fe bimetallic sulfide nanoflakes@porous carbon nanospheres as advanced anodes for high-performance potassium-/sodium-ion batteries

• Unique yolk–shell Ni–Fe sulfide@carbon is designed as an anode for K + / Na + batteries. • Such rational architecture offers enough spaces to buffer volume change of sulfides. • Mesoporous carbon shell improves electron transport rate and structural robustness. • NFS@C yolk-shell anodes exhibit enhanced K + / Na + storage performances. The identification of electrode materials suitable for hosting both K + and Na + is more challenging than that for Li + due to the larger ionic radii of K + and Na + . Thus, the design and fabrication of advanced electrode materials with excellent electrochemical properties for both potassium-ion batteries (KIBs) and sodium-ion batteries (SIBs) is extremely challenging. Herein, a unique yolk–shell-structured Ni–Fe bimetallic sulfide nanoflake@carbon nanosphere (NFS@C) is designed as a high-performance anode for both KIBs and SIBs via a combination of the infiltration method and sulfidation process. During the first infiltration process under vacuum, Ni and Fe precursors can easily penetrate though the shell into the central void of HMCSs with the help of capillary force. The subsequent sulfidation can transform these precursors into their corresponding sulfides, resulting in the formation of NFS@C yolk–shell nanospheres. These rationally engineered architectures provide enough space to buffer the huge volume expansion of Ni–Fe sulfides upon cycling and supply ample channels for the diffusion of ions, thus providing a well-defined conductive network in the entire electrode. Therefore, NFS@C yolk–shell nanospheres exhibit excellent cycling stability (297 mA h g −1 at 0.1 A g −1 after 250 cycles) and rate capability (52 mA h g −1 at 7.0 A g −1 ) for potassium storage. Furthermore, NFS@C nanospheres as anodes for SIBs exhibited high discharge capacity (417 mA h g −1 at 0.2 A g −1 after 250 cycles) and stable capacity (140 mA h g −1 ) even at a high current density (10.0 A g −1 ).

Construction of novel BiOIO3/MoS2 2D/2D heterostructures with enhanced photocatalytic activity

Abstract A novel BiOIO3/MoS2 (BM-x) 2D/2D heterostructure was firstly constructed by hybridizing BiOIO3 with MoS2 through solvothermal process. The formation of BM-x 2D/2D heterostructure with higher specific surface area and larger interfaces can offer ample channel for the transmission of charge, confirmed by SEM, TEM, BET and EIS. Introduction of MoS2 could improve light harvesting abilities of BM-x composites, which was demonstrated by DRS. Moreover, a staggered type-Ⅱ heterojunction and built-in electric field between BiOIO3 and MoS2 were formed, facilitating the separation of photogenerated carriers, proven via transient photocurrent response and PL. The BM-x composites could be applied to the photocatalytic degradation of rhodamine B (RhB). Above properties endow BM-x composites enhanced photocatalytic efficiencies for degradation of RhB than pure BiOIO3 under simulated solar-light irradiation, and the BM-1.0 composite showed the optimized degradation rate constant (0.04189 min−1), which is 5.2 times higher than that of pristine BiOIO3 (0.00811 min−1). Free radical scavenging experiments reveal that h+ and •O2− are primarily responsible for the photocatalytic degradation of RhB in this system, and a possible type-Ⅱ heterojunction mechanism with dye sensitization was proposed.

Toward Proper Guard Zones for Link Signature

Motivated by information-theoretic security, link signature (LS)-based security mechanisms exploit the ample channel characteristics between wireless devices for security establishment. Nevertheless, LS is originated from wireless environments and hence may exhibit potential vulnerabilities that can be exploited by adversary in the vicinity. As to this, it is widely believed in existing literature on LS that, a half-wavelength guard zone is sufficient to decorrelate the adversary channel from the legitimate one and thereby secures the legitimate LS. However, such an assumption may not hold universally—in some environments, high channel correlations have been observed for much larger spatial separations. Considering this, a comprehensive understanding of channel correlation in different wireless environments is needed for more confident deployment of LS-based security mechanisms. To this end, various well-established channel correlation models are investigated in this work. A set of important physical factors that have significant influence on LS security are identified, and with the obtained insights, extensive simulations are conducted to explore suitable guard zone sizes for LS in several typical indoor and outdoor environments. Experimental results based on universal software radio peripheral (USRP) platforms and GNURadio are also presented to further support the analysis.

Upper Limits on Achievable Storage Density Using Turbo Equalization in 2-D Magnetic Recording

The maximum amounts of 2-D intersymbol interference that can be tolerated by the specific types of turbo equalizers are analyzed using the extrinsic information transfer charts. The results translate into the maximum normalized user density that each equalizer can support given an ample channel signal-to-noise ratio. It is shown that a low-complexity self-iterating equalizer based on individually weak linear component equalizers running in different directions provides excellent performance.

Plasmid Conjugation from Proteobacteria as Evidence for the Origin of Xenologous Genes in Cyanobacteria

Comparative genomics have shown that 5% of Synechococcus elongatus PCC 7942 genes are of probable proteobacterial origin. To investigate the role of interphylum conjugation in cyanobacterial gene acquisition, we tested the ability of a set of prototype proteobacterial conjugative plasmids (RP4, pKM101, R388, R64, and F) to transfer DNA from Escherichia coli to S. elongatus. A series of BioBrick-compatible, mobilizable shuttle vectors was developed. These vectors were based on the putative origin of replication of the Synechococcus resident plasmid pANL. Not only broad-host-range plasmids, such as RP4 and R388, but also narrower-host-range plasmids, such as pKM101, all encoding MPFT-type IV secretion systems, were able to transfer plasmid DNA from E. coli to S. elongatus by conjugation. Neither MPFF nor MPFI could be used as interphylum DNA delivery agents. Reciprocally, pANL-derived cointegrates could be introduced in E. coli by electroporation, where they conferred a functional phenotype. These results suggest the existence of potentially ample channels of gene flow between proteobacteria and cyanobacteria and point to MPFT-based interphylum conjugation as a potential mechanism to explain the proteobacterial origin of a majority of S. elongatus xenologous genes.

Public Opinion and the Development of the European Security and Defence Policy

This article argues that public opinion will become an increasingly significant constraint on European-level decision-making with regard to implementing and further developing the ESDP. The thesis is based on a theoretical concept that identifies two necessary preconditions for public opinion to impact upon governmental foreign policies, namely the public salience of foreign policy issues and the public’s opportunity structures to influence foreign policy decision-making. Any initiative to put into practice or extend the ESDP will have to be pursued in a political environment in which both preconditions will generally be met. First, the ESDP’s actions and aspirations touch upon issues that are of great salience to European publics. Second, European publics are provided with ample channels of influence to constrain European integration in this field via their respective national governments. Thus, the prospects of further developing the ESDP will depend increasingly on supportive public opinions in EU Member States.

High-efficiency, two-dimensional separations of protein digests on microfluidic devices.

High-efficiency, two-dimensional separations of tryptic digests were achieved using glass microfluidic devices. Following micellar electrokinetic chromatography (MEKC) separations in a 19.6-cm-long serpentine channel, the peptides were rapidly sampled into a 1.3-cm-long second-dimension channel, where they were separated by capillary electrophoresis (CE). The turns in the serpentine channel were asymmetrically tapered to minimize geometrical contributions to band broadening and to provide ample channel length for high-efficiency chromatographic separations. Analysis of rhodamine B injections routinely produced plate numbers of 230000 and 40000 in the first (MEKC) and second (CE) dimensions, respectively, corresponding to plate heights of 0.9 and 0.3 microm. The electric field strengths were 200 V/cm for MEKC and 2400 V/cm for CE. In analysis times less than 15 min, two-dimensional separation of bovine serum albumin tryptic digest produced a peak capacity of 4200 (110 in the first dimension and 38 in the second dimension). The system was used to identify a peptide from a tryptic digest of ovalbumin using standard addition and to distinguish between tryptic digests of human and bovine hemoglobin.