Evaluation of root lodging resistance during whole growth stage at the plant level in maize.

Root lodging due to strong storm wind is a common problem in maize (Zea mays) production, leading to reduced crop yield and quality and harvest efficiency. Little information is available on quantifying effects of vertical leaf area distribution on root lodging in crops such as maize. Anti-lodging index of root was computed by the formula: ALroot = Mroot / Mwind, where AL denotes anti-lodging index, and M moment of force. Mroot, root failure moment of force equals to moment arm times max root side-pulling force measured in situ by means of the digital pole dynamometer, and Mwind, wind resultant moment of force is estimated with vertical leaf area distribution and wind speed. Two maize cultivars were examined at 5 different growth stages from V8 to physiological maturity in 2019 and 2020, in Qingdao, China. Root anti-lodging index in tested cultivars fluctuated to a small extent within any year during whole growth period excluding at V8, while there was an inter-annual shift in index means (1.23 vs 0.84). Both root failure moment and wind resultant moment increased first and then decreased with the growth stage, and their influences on root anti-lodging index varied with the year. At wind grade 6, effect sizes, as contribution to root anti-lodging index, of root moment and wind moment were respectively 0.88 and 0.98. The difference in anti-lodging index between cultivars seemed to be disappearing as wind grade goes up. Root failure moment of force positively related to single root tensile resistance, root-soil ball volume, root number and total root length, whose correlation coefficient was the maximum of 0.94. Root anti-lodging index of maize proved stable from V8 on during whole growth period, and vertical leaf area distribution played a substantial role in maize root lodging in terms of wind resultant moment. Our findings provide the insights into root lodging events in crops such as maize, and would serve an approach to assessing crop root lodging resistance in breeding and cultivation programs.

Promoting Oxygen Evolution Reaction of Co-Based Catalysts (Co3 O4 , CoS, CoP, and CoN) through Photothermal Effect.

The increase of reaction temperature of electrocatalysts is regarded as an efficient method to improve the oxygen evolution reaction (OER) activity. Herein, it is reported that the electrocatalytic performance of dual functional (i.e., electrocatalytic and photothermal functions) Co3 O4 can be dramatically improved via its photothermal effect. The operating temperature of the Co3 O4 electrode is elevated in situ under near infrared (NIR) light irradiation, resulting in enhanced oxygen evolution activity due to its accelerated electrical conductivity, reaction kinetics, and desorption rate of O2 bubbles from the electrode. In addition, photothermal effect can also enhance the electrocatalytic reaction rates of metal-doped Co3 O4 electrodes, indicating that it is able to significantly improve the OER activities of electrodes together with other modification strategies. With the assistance of the photothermal effect, the obtained Ni-doped Co3 O4 catalyst requires an extremely low overpotential of 208 mV to achieve a benchmark of 10 mA cm-2 with a small Tafel slope, superior to most reported Co-based catalysts. Significantly, the electrocatalytic performance of other electrodes with photothermal effect, such as CoN, CoP, and CoS, are also boosted under NIR light irradiation, indicating opportunities for implementing photothermal enhancement in electrocatalytic water splitting.

Yield-Maturity Relationships of Summer Maize from 2003 to 2017 in the Huanghuaihai Plain of China.

Information on yield-maturity relationships is important for maize breeding and cultivation, but it is seldom available in geographic zones where there are limited heat resources for summer maize. Two novel systematic crop yield models were put forward in terms of production efficiency. These models as well as three other conventional models were used to analyze the crop yield and maturity dataset of 23,691 records that were collected from the annual reports for the national summer maize zonal trials conducted in the Huanghuaihai Plain of China during 2003 to 2017. (1) Crop yield increases were usually below 14.5 kg/666.7 m2 due to longer maturity days, varying from 1 d to 15 d increments. Maize hybrids with later maturity fell into five categories: statistically significantly less, not significantly less, the same, not significantly more, or statistically significantly more output than their earlier counterparts. (2) Three yield components acted on crop yield gaps in the order of descending effects as kernel number per ear ≈ 1000-kernel weight > ear number per unit land area. (3) Space production efficiency was more important than canopy volume to crop yield. (4) Time production efficiency was dominant and maturity was negligible in crop yield formation. The findings provide insights into yield-maturity relationships in maize and useful information for summer maize breeding and cultivation strategies.

Tailoring TiO2 Nanotube-Interlaced Graphite Carbon Nitride Nanosheets for Improving Visible-Light-Driven Photocatalytic Performance.

Rapid recombination of photoinduced electron-hole pairs is one of the major defects in graphitic carbon nitride (g-C3N4)-based photocatalysts. To address this issue, perforated ultralong TiO2 nanotube-interlaced g-C3N4 nanosheets (PGCN/TNTs) are prepared via a template-based process by treating g-C3N4 and TiO2 nanotubes polymerized hybrids in alkali solution. Shortened migration distance of charge transfer is achieved from perforated PGCN/TNTs on account of cutting redundant g-C3N4 nanosheets, leading to subdued electron-hole recombination. When PGCN/TNTs are employed as photocatalysts for H2 generation, their in-plane holes and high hydrophilicity accelerate cross-plane diffusion to dramatically promote the photocatalytic reaction in kinetics and supply plentiful catalytic active centers. By having these unique features, PGCN/TNTs exhibit superb visible-light H2-generation activity of 1364 µmol h-1 g-1 (λ > 400 nm) and a notable quantum yield of 6.32% at 420 nm, which are much higher than that of bulk g-C3N4 photocatalysts. This study demonstrates an ingenious design to weaken the electron recombination in g-C3N4 for significantly enhancing its photocatalytic capability.

Carbon Quantum Dot Implanted Graphite Carbon Nitride Nanotubes: Excellent Charge Separation and Enhanced Photocatalytic Hydrogen Evolution.

Graphite carbon nitride (g-C3 N4 ) is a promising candidate for photocatalytic hydrogen production, but only shows moderate activity owing to sluggish photocarrier transfer and insufficient light absorption. Herein, carbon quantum dots (CQDs) implanted in the surface plane of g-C3 N4 nanotubes were synthesized by thermal polymerization of freeze-dried urea and CQDs precursor. The CQD-implanted g-C3 N4 nanotubes (CCTs) could simultaneously facilitate photoelectron transport and suppress charge recombination through their specially coupled heterogeneous interface. The electronic structure and morphology were optimized in the CCTs, contributing to greater visible light absorption and a weakened barrier of the photocarrier transfer. As a result, the CCTs exhibited efficient photocatalytic performance under light irradiation with a high H2 production rate of 3538.3 µmol g-1 h-1 and a notable quantum yield of 10.94 % at 420 nm.

Ordered Single-Crystalline Anatase TiO2 Nanorod Clusters Planted on Graphene for Fast Charge Transfer in Photoelectrochemical Solar Cells.

Achieving efficient charge transport is a great challenge in nanostructured TiO2 -electrode-based photoelectrochemical cells. Inspired by excellent directional charge transport and the well-known electroconductibility of 1D anatase TiO2 nanostructured materials and graphene, respectively, planting ordered, single-crystalline anatase TiO2 nanorod clusters on graphene sheets (rGO/ATRCs) via a facial one-pot solvothermal method is reported. The hierarchical rGO/ATRCs nanostructure can serve as an efficient light-harvesting electrode for dye-sensitized solar cells. In addition, the obtained high-crystallinity anatase TiO2 nanorods in rGO/ATRCs possess a lower density of trap states, thus facilitating diffusion-driven charge transport and suppressing electron recombination. Moreover, the novel architecture significantly enhances the trap-free charge diffusion coefficient, which contributes to superior electron mobility properties. By virtue of more efficient charge transport and higher energy conversion efficiency, the rGO/ATRCs developed in this work show significant advantages over conventional rGO-TiO2 nanoparticle counterparts in photoelectrochemical cells.

Gluing bifurcation and noise-induced hopping in the oscillatory phenomena of compartmentalized bidisperse granular gases.

Oscillatory phenomena of compartmentalized bidisperse granular gases are studied through experiments, molecular dynamics simulations, and a flux model [Mikkelsen et al., Phys. Rev. E 70, 061307 (2004)]. The degenerate oscillatory state (d-OSC), which has been predicted in our previous simulations [Liu et al., Phys. Rev. E 79, 052301 (2009)], is experimentally observed and well described by the flux model. From the d-OSC state, the system takes a transition to a complete oscillatory state (OSC) through a homoclinic gluing bifurcation. Around the bifurcation point, noise-induced periodic irregularity is observed, and it can be perfectly reproduced by simulations and the flux model with additional random flux terms. The numerical results show a low-frequency divergence characteristic of the irregular oscillation, which is clearly caused by noise-induced hopping between OSC and d-OSC states.

Elastic waves in the presence of a granular shear band formed by direct shear.

The propagation of elastic waves in a box under direct shear, filled with glass beads and being sheared at constant rates, is studied experimentally and theoretically. The respective velocities are shown to be essentially unchanged from that in a static granular system under the same pressure and shear stress but without a shear band. Influence of shear band on sound behaviors are also briefly discussed.

Traveling shock front in quasi-two-dimensional granular flows.

While the density profile of a granular shock front can be obtained by the conventional treatment of supersonic fluids, its temperature profile is very different from that in ordinary shocks. We study the density and temperature profiles of a traveling granular shock generated by piling up metal spheres in a closed bottom quasi-two-dimensional channel. We successfully account for the temperature profile in the granular shock using a simple kinetic theory in terms of energy transfer from the mean flow direction to the transverse direction. Contrary to ordinary fluids and previous granular shock experiments, the granular shock width is found to increase with the inflow rate.

Oscillatory phenomena of compartmentalized bidisperse granular gases.

Compartmentalized bidisperse granular gases are numerically studied. Molecular-dynamics simulations studying granular clock phenomenon in three dimensions are presented, which complement previously reported two-dimensional simulation results. A flux model for binary mixtures is found to give qualitative descriptions for the oscillations, with no undetermined parameters or functions. Two different states, a degenerate oscillatory state and a state with large particles segregated and small particles homogeneously distributed, are found in our simulations. These features reveal a much more complex phase diagram for the system, which challenges the existing theoretical models.

Temperature oscillations in a compartmentalized bidisperse granular gas.

A granular clock is observed in a vertically vibrated compartmentalized granular gas composed of two types of grains with the same size. The dynamics of the clock is studied in terms of an unstable evaporation or condensation model for the granular gas. In this model, the temperatures of the two types of grains are considered to be different, and they are functions of the composition of the gas. Oscillations in the system are driven by the asymmetric collisions properties between the two types of grains. Both our experiments and model show that the transition of the system from a homogeneous state to an oscillatory state is via a Hopf bifurcation.

van der Waals-like phase-separation instability of a driven granular gas in three dimensions.

We show that the van der Waals-like phase-separation instability of a driven granular gas at zero gravity, previously investigated in two-dimensional settings, persists in three dimensions. We consider a monodisperse granular gas driven by a thermal wall of a three-dimensional rectangular container at zero gravity. The basic steady state of this system, as described by granular hydrodynamic equations, involves a denser and colder layer of granulate located at the wall opposite to the driving wall. When the inelastic energy loss is sufficiently high, the driven granular gas exhibits, in some range of average densities, negative compressibility in the directions parallel to the driving wall. When the lateral dimensions of the container are sufficiently large, the negative compressibility causes spontaneous symmetry breaking of the basic steady state and a phase separation instability. Event-driven molecular dynamics simulations confirm and complement our theoretical predictions.

Influence of electric field on the phase transitions of the hexagonal cylinder phase of diblock copolymers.

We have used the cell dynamic simulations (CDS) method to study the evolution of asymmetric and symmetric diblock copolymers under electric fields. For symmetric diblock copolymers, long-range-ordered lamellar phases form readily under electric fields. For asymmetric diblock copolymers, sphere-to-cylinder phase transitions occur rapidly when strong electric fields are applied, but it takes longer for the system to form hexagonal cylinder structures. The results of these simulations suggest that the sphere phase is stable under weak electric fields, but a threshold electric intensity exists for the sphere-to-cylinder phase transition. In addition, we also studied the kinetic pathways of the transition of the lamellar phase to the hexagonal cylinder phase of the asymmetric diblock copolymers under electric fields. Hexagonal cylinder structures form when the lamellar phase is subjected to a sudden temperature jump. The scattering functions suggest that the hexagonal cylinder structures are very regular and possess very few flaws.