Memristor, which had been predicted a long time ago (Chua, L. O. IEEE Trans. Circuit Theory 1971, 18, 507), was recently invented (Strukov, D. B.; et al. Nature 2008, 453, 80). The introduction of a memristor is expected to open a new era for nonvolatile memory storage, neuromorphic computing, digital logic, and analog circuit. Furthermore, several breakthroughs were made for memristive phenomena and transistors with single-layer MoS2 (Sangwan, V. K.; et al. Nat. Nanotechnol. 2015, 10, 403. van der Zande, A. M.; et al. Nat. Mater. 2013, 12, 554. Liu, H.; et al. ACS Nano 2014, 8, 1031. Bessonov, A. A.; et al. Nat. Mater. 2015, 14, 199. Yuan, J.; et al. Nat. Nanotechnol. 2015, 10, 389). Herein, we demonstrate that 2H phase of bulk MoS2 possessed an ohmic feature, whereas 1T phase of exfoliated MoS2 nanosheets exhibited a unique memristive behavior due to voltage-dependent resistance change. Furthermore, an ideal odd-symmetric memristor with odd-symmetric I-V characteristics was successfully fabricated by the 1T phase MoS2 nanosheets via combining two asymmetric switches antiserially.

The large energy requirement of CO 2 reforming of methane (CRM) has obstructed its application. Solar energy is a solution for the issue. Different from efficient photocatalytic splitting of water, photocatalysis for CRM exhibits a very low efficiency and employs only ultraviolet (UV) light. This letter reports an efficient visible-light photocatalytic CRM by combining Pt/black TiO 2 catalyst with lightdiffuse-reflection-surface. Under visible light illumination by filtering UV light from AM 1.5G sunlight, H 2 and CO yields reached 71 and 158 mmol/h/g cat , with a quantum efficiency of 32.3% at 550 °C, and 129 and 370 mmol/h/g cat , with a quantum efficiency of 57.8% at 650 °C. Those yields are 3 orders of magnitude larger than the reported values.

Atomically thin graphene with a high-density of precise subnanometer pores represents the ideal membrane for ionic and molecular separations. However, a single large-nanopore can severely compromise membrane performance and differential etching between pre-existing defects/grain boundaries in graphene and pristine regions presents fundamental limitations. Here, we show for the first time that size-selective interfacial polymerization after high-density nanopore formation in graphene not only seals larger defects (>0.5 nm) and macroscopic tears but also successfully preserves the smaller subnanometer pores. Low-temperature growth followed by mild UV/ozone oxidation allows for facile and scalable formation of highdensity (4−5.5 × 10 12 cm −2 ) useful subnanometer pores in the graphene lattice. We demonstrate scalable synthesis of fully functional centimeter-scale nanoporous atomically thin membranes (NATMs) with water (∼0.28 nm) permeance ∼23× higher than commercially available membranes and excellent rejection to salt ions (∼0.66 nm, >97% rejection) as well as small organic molecules (∼0.7−1.5 nm, ∼100% rejection) under forward osmosis.

We report on a roll-to-roll manufacturing compatible isopropanol-assisted-hot-lamination process for facile fabrication of large-area nanoporous atomically thin graphene membranes (NATMs) for dialysis and molecular separations.

a b s t r a c tIn this work, we revisit implementation issues in the lattice Boltzmann method (LBM) concerning moving rigid solid particles suspended a viscous fluid. Three aspects relevant to the interaction between flow of a viscous fluid and moving solid boundaries are considered. First, the popular interpolated bounce back scheme is examined both theoretically and numerically. It is important to recognize that even though significant efforts had previously been devoted to the performance, especially the accuracy, of different interpolated bounce back schemes for a fixed boundary, there were relatively few studies focusing on moving solid surfaces. In this study, different interpolated bounce back schemes are compared theoretically for a moving boundary. Then, several benchmark cases are presented to show their actual performance in numerical simulations. Second, we examine different implementations of the momentum exchange method to calculate hydrodynamic force and torque acting on a moving surface. The momentum exchange method is well established for fixed solid boundaries, however, for moving solid boundaries there are still open issues such as unphysical force fluctuations and Galilean invariance errors. Recent progress in this direction is discussed, along with our own interpretations and modifications. Several benchmark cases, including a particle-laden turbulent channel flow, are used to demonstrate the effects of different modifications on the accuracy and physical results under different physical configurations. The third aspect is the refilling scheme for constructing the unknown distribution functions for the new fluid nodes that emerge from the previous solid region as a particle moves relative to a fixed lattice grid. We examine and compare the performance of the refilling schemes introduced by Fang et al. (2002), Caiazzo (2008). We demonstrate that improvements can be made to suppress force fluctuations resulting from refilling.

It is generally recognized that H 2 O adsorption on a porous material would inhibit H 2 adsorption. However, this paper reports that stable H 2 O-functionalized Zeolitic Zn(2-methylimidazole) 2 Framework (ZIF-8), which was obtained by the simple water treatment of ZIF-8 at ambient temperature, can increase its H 2 adsorption heat from 5.2 to 10.1 kJ/mol. As a result, the reversible H 2 capacity at ambient temperature increased by 77%. This indicates that H 2 O-functionalization provides a novel approach to enhance ambient-temperature hydrogen storage in ZIF-8 and other metal-organic frameworks (MOFs).

High quality methylammonium bismuth iodide films made using atmospheric pressure chemical vapor deposition.

Understanding the two-way interactions between finite-size solid particles and a wall-bounded turbulent flow is crucial in a variety of natural and engineering applications. Previous experimental measurements and particle-resolved direct numerical simulations revealed some interesting phenomena related to particle distribution and turbulence modulation, but their in-depth analyses are largely missing. In this study, turbulent channel flows laden with neutrally buoyant finite-size spherical particles are simulated using the lattice Boltzmann method. Two particle sizes are considered, with diameters equal to 14.45 and 28.9 wall units. To understand the roles played by the particle rotation, two additional simulations with the same particle sizes but no particle rotation are also presented for comparison. Particles of both sizes are found to form clusters. Under the Stokes lubrication corrections, small particles are found to have a stronger preference to form clusters, and their clusters orientate more in the streamwise direction. As a result, small particles reduce the mean flow velocity less than large particles. Particles are also found to result in a more homogeneous distribution of turbulent kinetic energy (TKE) in the wall-normal direction, as well as a more isotropic distribution of TKE among different spatial directions. To understand these turbulence modulation phenomena, we analyse in detail the total and component-wise volume-averaged budget equations of TKE with the simulation data. This budget analysis reveals several mechanisms through which the particles modulate local and global TKE in the particle-laden turbulent channel flow.