A wide range of inorganic nanostructures have been used as photocatalysts for generating H 2 . To increase activity, Z‐scheme photocatalytic systems have been implemented that use multiple types of photoactive materi...
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A wide range of inorganic nanostructures have been used as photocatalysts for generating H 2 . To increase activity, Z‐scheme photocatalytic systems have been implemented that use multiple types of photoactive materials and electron mediators. Optimal catalysis has previously been obtained by interfacing different materials through aggregation or epitaxial nucleation, all of which lowers the accessible active surface area. DNA has now been used as a structure‐directing agent to organize TiO 2 and CdS nanocrystals. A significant increase in H 2 production compared to CdS or TiO 2 alone was thus observed directly in solution with no sacrificial donors or applied bias. The inclusion of benzoquinone (BQ) equidistant between the TiO 2 and CdS through DNA assembly further increased H 2 production. While the use of a second quinone in conjunction with BQ showed no more improvement, its location within the Z‐scheme was found to strongly influence catalysis.
We have developed a Green-Kubo relation that enables accurate calculations of friction at solid-liquid interfaces directly from equilibrium molecular dynamics (MD) simulations and that provides a pathway to bypass the...
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We have developed a Green-Kubo relation that enables accurate calculations of friction at solid-liquid interfaces directly from equilibrium molecular dynamics (MD) simulations and that provides a pathway to bypass the time-scale limitations of typical nonequilibrium MD simulations. The theory has been validated for a number of different interfaces and it is demonstrated that the liquid-solid slip is an intrinsic property of an interface. Because of the high numerical efficiency of our method, it can be used in the design of interfaces for applications in aqueous environments, such as nano- and microfluidics.
Poly(vinyl alcohol) (PVOH)-based aerogel composites with nanoscale silica, halloysite, montmorillonite (MMT), and laponite were prepared via a freeze-drying method. The PVOH/MMT and PVOH/laponite composites exhibit hi...
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It is extremely difficult to incorporate and disperse nanoparticles (NPs), especially for a high percentage, into metal matrix during solidification processing to achieve crucial property enhancement in metal matrix n...
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ISBN:
(纸本)9781118888162
It is extremely difficult to incorporate and disperse nanoparticles (NPs), especially for a high percentage, into metal matrix during solidification processing to achieve crucial property enhancement in metal matrix nanocomposites (MMNCs), mainly due to the strong tendency of NP aggregation. Thus, the significant property enhancement expected by the addition of a high percentage of NPs is rarely achieved in solidification processing of bulk MMNCs. Here we show that an unprecedented uniform distribution of 5 vol.% SiC NPs in Mgl8Sn alloy matrix is obtained by solidification processing. The resulting Mgl8Sn matrix nanocomposites exhibits a very high microhardness value of 150 kg/mm2. The results reported in this work shed light on a potential pathway for production of ultrahigh performance metallic nanocomposites.
Optical-pump terahertz-probe spectroscopy is used to investigate ultrafast far-infrared conductivity dynamics during the insulator-to-metal transition in vanadium sesquioxide (V2O3). The resultant conductivity increas...
Optical-pump terahertz-probe spectroscopy is used to investigate ultrafast far-infrared conductivity dynamics during the insulator-to-metal transition in vanadium sesquioxide (V2O3). The resultant conductivity increase occurs on a tens of picosecond time scale, exhibiting a strong dependence on the initial temperature and fluence. We have identified a scaling of the conductivity dynamics upon renormalizing the time axis with a simple power law (α≃1/2) that depends solely on the initial, final, and conductivity onset temperatures. Qualitative and quantitative considerations indicate that the dynamics arise from nucleation and growth of the metallic phase which can be described by the Avrami model. We show that the temporal scaling arises from spatial scaling of the growth of the metallic volume fraction, highlighting the self-similar nature of the dynamics. Our results illustrate the important role played by mesoscopic effects in phase transition dynamics.
A quartz crystal microbalance (QCM) technique was used to reveal the effect of alkanethiol self-assembled monolayers (SAMs) on the viscoelastic property and cell adhesion process of cultured fibroblasts (L929), by mea...
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