Graphene is easily produced by thermally reducing graphene oxide. However, defect formation in the C network during deoxygenation compromises charge carrier mobility reduced material. Understanding mechanisms of thermal reactions essential for defining alternative routes able to limit density defects generated carbon evolution. Here, we identify a dual path mechanism reduction oxide driven oxygen coverage: at low surface density, O atoms adsorbed as epoxy groups evolve O2 leaving unmodified....

Purpose: To investigate the effect of home quarantine during COVID-19 pandemic on myopia progression in children and its associated factors. Methods: Myopic aged 7 to 12 years with regular follow-up visits every half a year from April 2019 May 2020 were included. Cycloplegic refraction was measured at baseline two visits. The first visit (visit 1) conducted before quarantine, whereas second 2) four months after quarantine. Myopia 1 2 compared. Factors changes tested multiple regression...

The initial oxidation stages of perfect and defective graphitic surfaces exposed to atomic oxygen have been studied with a combined high-resolution photoemission spectroscopy (HR-PES) density functional theory (DFT) computational approach. resulting oxygen-containing surface groups are identified by analyzing the multicomponent C 1s O core level spectra that then interpreted on basis DFT calculations. In stage, epoxy formed graphene, whereas preferential adsorption atoms vacancies results in...

We describe gold nanocages as a new class of potential contrast agent for spectroscopic optical coherence tomography (OCT). Monodispersed an ∼35 nm edge length exhibit strong resonance, with the peak wavelength tunable in near-infrared range. characterized properties nanocage by using OCT experiments along numerical calculations, revealing absorption cross section approximately 5 orders magnitude larger than conventional dyes. Experiments tissue phantoms demonstrated that provide enhanced...

The dynamics of a growing interface with conservation total volume under the is investigated using both dynamic renormalization-group and computer simulation. law leads to new universality class from that discussed by Kardar, Parisi, Zhang [Phys. Rev. Lett. 56, 889 (1986)]. growth exponents are calculated compared those simulation conserved restricted solid-on-solid model. Excellent agreement between theory found.

We identify mechanisms and surface precursors for the nucleation growth of extended defects on oxidized graphene. Density functional theory calculations show that formation structures capable to initiate unzipping cracking C network is strongly influenced by constraint graphitic lattice groups. Accounting this effect preferential spatial patterning O adsorbates allows us revise extend current models graphene oxidative cutting. find these processes are rate limited diffusion driven local...

We use a hybrid strategy to obtain anharmonic frequency shifts and lifetimes of phonon quasi-particles from first principles molecular dynamics simulations in modest size supercells. This approach is effective irrespective crystal structure complexity facilitates calculation full dispersions, as long are well defined. validate this effects with calculations MgSiO3-perovskite, the major Earth forming mineral phase. First, we reproduce irregular temperature induced characterized Raman modes....

The stability of cubic $\mathrm{Ca}\mathrm{Si}{\mathrm{O}}_{3}$ perovskite (CaPv) at high temperatures and pressures is investigated by vibrational normal-mode analysis. We compute power spectra mode autocorrelation functions using a recently developed hybrid approach combining ab initio molecular dynamics with lattice dynamics. These spectra, together the probability distributions atomic displacements, indicate that CaPv stabilized $T\ensuremath{\sim}600$ K $P\ensuremath{\sim}$ 26 GPa. then...

Sulfurized polyacrylonitrile (PAN@S) is a promising cathode material for room-temperature Na/S batteries but suffers from low conductivity and insufficient electrochemical activity, resulting in unsatisfactory actual capacity rate performance. Herein, Ti3C2Tx MXene nanosheets are used as conductive catalytic binder to establish the PAN@S electrode, wherein constructs highly framework fast charge transport provides high effect improve active utilization accelerate redox kinetics...

The reduction of graphene oxide surfaces yielding molecular CO/CO2 is studied from first principles using density functional theory. We find that this reaction can proceed exothermically only surface precursors containing more oxygen atoms than strictly needed to produce in the gas phase. calculations show lowest-energy configurations multiple O adsorbates do not involve clustering epoxy groups (the stable form adatoms on graphitic surfaces) but always contain lactone either lactone−ether or...

The root microbiota plays a crucial role in assisting the plant host combating various biotic and abiotic stresses, notably drought, which poses significant threat to global food security. Despite extensive efforts understand shifts rhizosphere endosphere bacteriomes, there remains gap comprehending how drought stress influences co-occurring network patterns within these compartments their ecological functional potentials. To address this gap, pot experiment was conducted with two...

We use classical molecular dynamics to evaluate the thermal conductivity $\ensuremath{\kappa}(T)$ from heat-flux correlation $⟨\mathbf{j}(0)\mathbf{j}(t)⟩$ for a two-dimensional Lennard-Jones triangular lattice. Our work, which follows Ladd, Moran, and Hoover [Phys. Rev. B 34, 5058 (1986)], finds large deviations Eucken-Debye result $\ensuremath{\kappa}(T)=A/T$ predicted by phonon-gas model, even though phonon quasiparticles are fairly well defined. The main source of comes higher order...

We present a general scheme to accurately determine melting properties of materials from ab initio free energies. This does not require prior fitting system-specific interatomic potentials and is straightforward implement. For the solid phase, ionic entropies are determined phonon quasiparticle spectra (PQS), which fully account for lattice anharmonicity in thermodynamic limit. The resulting energies nearly identical (within 10 meV/atom) those computationally more demanding integration (TI)...

We investigated the vibrational property of lead telluride (PbTe) with a focus on lattice anharmonicity at moderate temperatures $(300<T<800$ K) using phonon quasiparticle approach which combines first-principles molecular dynamics and dynamics. The calculated anharmonic dispersions are strongly temperature dependent some modes adopt giant frequency shifts, e.g., transverse optical in long-wavlength regime. As result, we witness avoided crossing between longitudinal acoustic elevated...

The revised details of SY/T5358—2010 National Energy Administration Standard from five aspects are put forward, it is aimed at existing flaws the standard, including measurement procedures, evaluation method and discrimination criteria rock stress sensitivity. Terzaghi's effective was derived according to equation Bane Maximov, which indicates Terzaghi formula, not only suitable for soil mechanics, but also mechanics. An exponential model permeability built former researcher's formula...

A novel scheme to generate broadband high-repetition-rate optical frequency combs and low phase noise microwave signals simultaneously is proposed experimentally demonstrated. By incorporating an comb generator in optoelectronic oscillator loop, more than 200 lines are generated for a 25 GHz comb, the single-sideband as −122 dBc/Hz at 10 kHz offset signal. 20 also generated. Unlike synthesizer, of by this new independent.