Performance of Intrinsic and Modified Graphene for the Adsorption of H2S and CH4: A DFT Study

In this study, the adsorption performances of graphene before and after modification to H2S and CH4 molecules were studied using first principles with the density functional theory (DFT) method. The most stable adsorption configuration, the adsorption energy, the density of states, and the charge transfer are discussed to research the adsorption properties of intrinsic graphene (IG), Ni-doped graphene (Ni–G), vacancy defect graphene (DG), and graphene oxide (G–OH) for H2S and CH4. The weak adsorption and charge transfer of IG achieved different degrees of promotion by doping the Ni atom, setting a single vacancy defect, and adding oxygen-containing functional groups. It can be found that a single vacancy defect significantly enhances the strength of interaction between graphene and adsorbed molecules. DG peculiarly shows excellent adsorption performance for H2S, which is of great significance for the study of a promising sensor for H2S gas

Hydrothermal Synthesis of SnO2 Nanoneedle-Anchored NiO Microsphere and its Gas Sensing Performances

In this study, we reported a successful synthesis of a nanocomposite based on SnO2 nanoneedles anchored to NiO microsphere by a simple two-step hydrothermal route. The results show that the SnO2/NiO nanocomposite-based sensor exhibits more prominent performances than the pristine NiO microsphere to NO2 such as larger responses and more outstanding repeatability. The improved properties are mainly attributed to the p–n heterojunctions formed at the SnO2–NiO interface, leading to the change of potential barrier height and the enlargement of the depletion layer. Besides, the novel and unique nanostructure provides large and effective areas for the surface reaction. In addition, a plausible growth mechanism and the enhanced sensing mechanism were proposed to further discuss the special nanostructure which will benefit the exploration of high-performance sensors

Responses of Hydrological Processes under Different Shared Socioeconomic Pathway Scenarios in the Huaihe River Basin, China

The Coupled Model Intercomparison Project Phase 6 (CMIP6) provides more scenarios and reliable climate change results for improving the accuracy of future hydrological parameter change analysis. This study uses five CMIP6 global climate models (GCMs) to drive the variable infiltration capacity (VIC) model, and then simulates the hydrological response of the upper and middle Huaihe River Basin (UMHRB) under future shared socioeconomic pathway scenarios (SSPs). The results show that the five-GCM ensemble improves the simulation accuracy compared to a single model. The climate over the UMHRB likely becomes warmer. The general trend of future precipitation is projected to increase, and the increased rates are higher in spring and winter than in summer and autumn. Changes in annual evapotranspiration are basically consistent with precipitation, but seasonal evapotranspiration shows different changes (0–18%). The average annual runoff will increase in a wavelike manner, and the change patterns of runoff follow that of seasonal precipitation. Changes in soil moisture are not obvious, and the annual soil moisture increases slightly. In the intrayear process, soil moisture decreases slightly in autumn. The research results will enhance a more realistic understanding of the future hydrological response of the UMHRB and assist decision-makers in developing watershed flood risk-management measures and water and soil conservation plans

Transverse Photonic Crystal Mode Engineering for Broad-Area Semiconductor Lasers With Narrow-Divergence Angles

Broad-area semiconductor lasers, coupled with asymmetric transverse photonic crystals (TPCs), are designed by the effective index method and the transfer matrix method. Due to the propagation constant of the fundamental mode lying in the forbidden band of the TPCs, but those of the high-order modes lying in the allowed band of the TPCs, the fundamental mode is mainly concentrated in the active ridge waveguide, while all the high-order modes extend into the lossy TPCs on both sides of the active ridge waveguide. Therefore, the fundamental mode possesses larger optical confinement factor than those of the high-order modes, and reaches the lasing threshold more easily, which is demonstrated by the single-lobe horizontal far-field pattern of the TPC broad-area laser under an injection current of 0.3 A near the threshold. The proposed TPC broad-area laser provides a new strategy of designing broad-area semiconductor lasers with narrow divergence angles

Analysis of the Xyloglucan Endotransglucosylase/Hydrolase Gene Family during Apple Fruit Ripening and Softening

Ethylene and xyloglucan endotransglucosylase/hydrolase (<i>XTH</i>) genes were important for fruit ripening and softening in ‘Taishanzaoxia’ apple. In this study, we found it was <i>ACS1-1/-1</i> homozygotes in ‘Taishanzaoxia’ apple, which determined the higher transcription activity of <i>ACS1</i>. <i>XTH1</i>, <i>XTH3</i>, <i>XTH4</i>, <i>XTH5</i>, and <i>XTH9</i> were mainly involved in the early fruit softening independent of ethylene, while <i>XTH2</i>, <i>XTH6</i>, <i>XTH7</i>, <i>XTH8</i>, <i>XTH10</i>, and <i>XTH11</i> were predominantly involved in the late fruit softening dependent on ethylene. Overexpression of <i>XTH2</i> and <i>XTH10</i> in tomato resulted in the elevated expression of genes involved in ethylene biosynthesis (<i>ACS2</i>, <i>ACO1</i>), signal transduction (<i>ERF2</i>), and fruit softening (<i>XTHs</i>, <i>PG2A</i>, <i>Cel2</i>, and <i>TBG4</i>). In summary, the burst of ethylene in ‘Taishanzaoxia’ apple was predominantly determined by <i>ACS1-1/-1</i> genotype, and the differential expression of <i>XTH</i> genes dependent on and independent of ethylene played critical roles in the fruit ripening and softening. <i>XTH2</i> and <i>XTH10</i> may act as a signal switch in the feedback regulation of ethylene signaling and fruit softening