287 research outputs found

    475004_Visualization1.mp4

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    Animation of the quasi-CVT optimization process for an example Voronoi-Fresnel phase with 23 cells. The distance between the Voronoi-Fresnel phase and image sensor is set at 2 mm. The sensor pixels are 240 x 160, with a pixel pitch of 3.45 microns. The phase resolution is 1.15 microns, making a manufacturable 3x unsampling ratio compared with sensor resolution. To fully characterize the optimization, the process is run for 100 iterations, although the optimal result occurs in the early few iterations. (1) The phase profile at current iteration. (2) The generated PSF (shown in the square-root scale) at current iteration. (3) The MTF (shown in log scale) at current iteration. (4) The current optimal cell distribution with the maximum MTFv. Optimal result preserves both uniform and irregularity of the cells

    Active Sites of Pd-Doped Flat and Stepped Cu(111) Surfaces for H<sub>2</sub> Dissociation in Heterogeneous Catalytic Hydrogenation

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    It has been shown in recent experiments that the Cu(111) surface doped by a small amount of Pd atoms can exhibit excellent catalytic performance toward the dissociation of H<sub>2</sub> molecules. Here we performed systematic first-principles calculations to investigate the corresponding mechanism. Our results clearly demonstrate that a very small number of Pd atoms in the subsurface layer can effectively reduce the energy barrier of H<sub>2</sub> dissociation, making the ensembles composed of the surface and contiguous subsurface Pd atoms as the active sites. The catalytic activity can be further improved if the Pd atoms are doped in the stepped Cu surfaces. The impact of the subsurface Pd atoms comes from an enhanced surface–adsorbate interaction caused by adjusting the electronic structure of the substrate. The important role played by the subsurface atoms offers an efficient approach to finely tune the surface activity by a very limited number of atoms. Our findings should be very useful for understanding and improving the catalytic properties of alloy systems for the industrially important hydrogenation reactions

    Additional file 1 of HSPB1 as an RNA-binding protein mediates the pathological process of osteoarthritis

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    Additional file 1: Fig. S1 The reads density landscape of HSPB1-binding peaks on ROR2 transcripts. Table S1 Primers information of RT-qPCR

    Identification of the Scaling Relations for Binary Noble-Metal Nanoparticles

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    There exist a great many varieties of nanoparticles whose catalytic activities can be widely adjusted by changing their composition, shape, and size. Nørskov’s concepts to correlate the d-band center, adsorption energy, and activation energy offer an innovative approach to efficiently investigate the catalytic properties. Taking binary noble-metal polyhedral nanoparticles as representative systems, we found from first-principles simulations that the well-established scaling relations of the adsorption energies for extended surfaces can be seamlessly extended to the nanoscale. A systematic investigation of the correlation relations of the adsorption energies between the AH<sub><i>X</i></sub> groups and the corresponding A atoms in the binary noble-metal polyhedral nanoclusters of different compositions, shapes, and sizes clearly demonstrates the linear scaling relation. More remarkably, the scaling relation at the nanoscale can be effectively unified with the well-established scaling relations for extended surfaces. Such a description should be extremely helpful for the efficient screening of nanoparticles with superior catalytic properties

    Energy-Level Alignment at the Interface of Graphene Fluoride and Boron Nitride Monolayers: An Investigation by Many-Body Perturbation Theory

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    Energy-level alignment at interfaces is important for understanding and optimizing optoelectronic and photocatalytic properties. In this work, we study the level alignment at the interface between graphene fluoride and boron nitride monolayers. These two-dimensional (2D) semiconductors are representative wide-bandgap components for van der Waals (vdW) heterostructures. We perform a systematic study on the structural and electronic properties of their interface, by using density functional theory and the <i>G</i><sub>0</sub><i>W</i><sub>0</sub> method of many-body perturbation theory. We adopt this interface as a prototypical system to investigate the impact of polarization effects on band gap and level alignment. We find a small but still notable polarization-induced reduction of the materials’ band gap by 250 meV that we interpret and analyze in terms of an image-potential model. Such effects stem from nonlocal correlations between electrons and cannot be captured by semilocal or standard hybrid density functionals. Our work provides a lower limit of band-gap renormalization in 2D systems caused by polarization effects, and demonstrates the importance of many-body perturbation theory for a reliable prediction of energy-level alignment in 2D vdW heterojunctions

    The effect of iodide on the synthesis of gold nanoprisms

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    <div><p>It has been known that the iodide (I<sup>−</sup>) anions are necessary for the production of high-quality Au nanoprisms. Based on a previously reported seed-mediated synthesis of triangular gold nanoprisms, herein, we further optimised the synthesis process by varying the concentration of added NaI and seeds, respectively, to get high-quality (size-monodisperse, tip-sharp and purity-high) Au nanoprisms. The results show that the ratio between the concentration of I<sup>−</sup> and seeds is a very sensitive parameter to control the quality (size-monodispersity, tip-sharpness and purity) of Au nanoprisms.</p></div
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