Showing papers by "Baoshun Liu published in 2023"

Fermi-level shift, electron separation, and plasmon resonance change in Ag nanoparticle-decorated TiO2 under UV light illumination.

Abstract: Noble metal nanoparticles are widely used as co-catalysts for storing and separating electrons in semiconductor photocatalysis. Thus, evaluating this ability is important and meaningful to understand the photocatalytic mechanism. Employing Ag nanoparticles, the present study combined in situ photoconductance and theoretical analysis to evaluate the Fermi-level (EF) shift in a UV-illuminated Ag/TiO2 system under gaseous conditions. Based on this, the role of the Ag nanoparticles in storing and separating electrons was discussed. It was found that the EF of Ag/TiO2 is located deeper in the gap and a variation in temperature has less effect on the EF of Ag/TiO2 compared to the undecorated TiO2. The analysis showed that ∼46 electrons can be stored in 10 nm Ag nanoparticles under our experimental conditions, which does not change with temperature. The electron traps in TiO2 can affect the electron distribution in the TiO2 and Ag nanoparticles. It was observed that the localized surface plasmon resonance (LSPR) of the Ag nanoparticles exhibited a blue-shift under UV light illumination, which is generally ascribed to the electron storage in the Ag nanoparticles. However, we showed that the blue-shift is not related to the electron storage in the Ag nanoparticles, and thus it cannot be used as an indicator for evaluating their electron-storage ability. The in situ XPS analysis also does not support that the LSPR blue shift is associated with the reduction in the Ag2O layer and TiO2.

Association between red blood cell distribution width and left ventricular hypertrophy in pediatric essential hypertension

Abstract: Aim Left ventricular hypertrophy (LVH) is one of the most common types of target organ damage in hypertension. The red blood cell distribution width (RDW) is closely related to many cardiovascular diseases, including hypertension. The aim of this study was to analyze the relationship between the RDW level and LVH in pediatric essential hypertension. Materials and methods A total of 429 untreated children and adolescents with essential hypertension were recruited and divided into an LVH group (n = 114) and non-LVH group (n = 315) according to left ventricular mass index (LVMI) and relative wall thickness (RWT) by color Doppler ultrasound. Spearman correlation analysis was used to determine the relationship between RDW and LVMI, RWT. The effect of RDW on LVH was determined using a multivariate logistic regression analysis. To assess the predictive value of RDW on LVH, the receiver operating characteristic (ROC) curve was used. Results The level of RDW in children with hypertension in the LVH group was significantly higher than that in the non-LVH group (13.0 [12.0, 13.0] vs. 12.4 [12.0, 13.0] %, P = 0.001). The incidence of low and high quantiles of LVH was 21.0% and 32.0%, respectively. Spearman correlation analysis showed that RDW was positively correlated with C-reactive protein (CRP), LVMI, RWT, and red blood cell (RBC) count (P all < 0.05), and negatively correlated with hemoglobin (HGB) level, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC) (P all < 0.05). After adjusting for various confounding factors, a multivariate logistic regression model revealed that RDW was an independent risk factor for LVH (OR = 1.946, 95% CI: 1.324–2.861, P = 0.001). The area under the ROC curve of RDW predicting centripetal hypertrophy was 0.700 (95% CI: 0.541–0.859, P < 0.05) in pediatric essential hypertension. Conclusions Increased RDW levels are an independent risk factor for LVH in pediatric essential hypertension, and RDW may be a predictor of LVH in untreated pediatric essential hypertension.

Anthropogenic forcing and Pacific internal variability-determined decadal increase in summer precipitation over the Asian water tower

Abstract: Abstract The increased precipitation in the Asian water tower has prompted the abrupt lake expansion and increased runoff, significantly reshaping the water resource redistribution in the Inner Tibetan Plateau (ITP). However, the dynamic attribution behind this decadal increment remains unclear. Here, analysis of observations, large ensemble simulations, and pacemaker experiments indicates that this decadal increase was mainly attributed to the synergistic effects of the external forcing (anthropogenic greenhouse and aerosol emissions) and the Pacific internal variability, while the Atlantic and the Indian Ocean play a secondary role. Observations and simulations show that thermodynamic and dynamic effects work collaboratively to this increase. Remarkably, the upper-level dynamic convergence over the ITP would be enhanced through teleconnection and atmospheric dynamic feedback when involving the Pacific internal variability, resulting in more precipitation occurrence. Further analyses show that the enhanced stationary Rossby wave propagation over Eurasia and strengthened transient eddy activity over North Pacific could contribute to the anomalous cyclone over the ITP and weakened East Asian westerly jet, which built a pathway for the external forcing and Pacific internal variability collaboratively impacting the decadal increase in precipitation in the ITP. These results can improve our understanding of ITP summer precipitation attribution and can be applied to emergent constraints on future decadal precipitation prediction.

Atmosphere-Dependent Electron Relaxation of the Ag−Decorated TiO2 and the Relations with Photocatalytic Properties

Abstract: In the current research, the atmosphere effects on the photoinduced electron relaxations of the undecorated TiO2 and Ag-decorated TiO2 (Ag/TiO2) were carefully studied by means of the in situ photoconductance and diffuse reflection measurements. In pure N2 atmosphere, the results showed that the electron relaxation mainly occurs through the transfer to the residual O2, and the Ag nanoparticles form a fast electron transfer pathway. It was seen that the apparent activation energy of the electron transfer to O2 was greatly reduced by the Ag decoration. In the methanol-containing N2 atmosphere, the electron relaxation can still occur via the transfer to residual O2 in the case of the undecorated TiO2, while the relaxation mechanism changes for the Ag/TiO2 as the relaxations are decreased with the temperatures. It is possible that the methanol molecule adsorbed on the Ag/TiO2 perimeters could act as the bridge for the recombination of the holes and the electrons stored in the Ag nanoparticles. Reducing the Ag nanoparticle size from 15 nm to 3 nm can greatly increase the electron relaxations due to the increase in Ag dispersion and Ag/TiO2 interconnection. Although the electron transfer to O2 was increased, both the photocatalytic oxidations of acetone and isopropanol showed a decrease after the Ag decoration. The results indicated that the photocatalytic oxidation was not limited by the electron transfer to O2. The increased electron transfer to O2 contributed to the recombination around the Ag/TiO2 perimeters, and the photocatalytic activities were decreased.

Multi-feature combination method for point cloud intensity feature image and UAV optical image matching

Abstract: LiDAR point clouds and optical images are two widely used geospatial data. The fusion of LiDAR point clouds and optical images can take full advantage of these two types of data. Since LiDAR point clouds and optical images vary in dimension (3D vs. 2D), spectral (near-infrared vs. visible) and data acquisition principles ( time of flight vs. perspective projection), the fusion of LiDAR point clouds and optical images is challenging. This paper deals with the registration of LiDAR point clouds and optical images. Feature point-based matching methods with different feature detector and descriptor combinations are evaluated, and find that different combinations affect the matching performance greatly. Among the evaluated 112 combinations, FAST-SIFT and AGAST-SIFT combinations have the best matching performance. Besides, to remove the large amount mismatches in the matching results, the paper proposed a template and RANSAC based mismatch removal algorithm. The experimental results show that the proposed mismatch removal algorithm greatly improved the matching success rate and the correct matching rate.

Experimental and Molecular Investigation of Water Adsorption Controls in Marine and Lacustrine Shale Reservoirs

Abstract: The restriction of hydrocarbon migration within shale reservoirs by pre-adsorbed water necessitates an investigation into water adsorption control mechanisms within shales. In this study, water vapor adsorption isotherms obtained from marine and lacustrine shale samples along with isotherms from their organic matter and experimentally verified kerogen molecular models were used to evaluate water adsorption mechanisms, with simulated wet kerogen-quartz nanocomposites. Furthermore, these were also used to investigate organic matter-inorganic interaction controls on water adsorption. Pore size distribution (PSD) controls on water distribution in organic matter were obtained via water vapor adsorption and low-pressure nitrogen adsorption analysis, along with small angle neutron scattering (SANS) analysis. The results reveal water adsorption is linked to changes in mesopore volume within organic matter and porosity in kerogen models. PSD obtained from the shales only reveal mesopore controls at high RH, with water adsorption mainly controlled by oxygen functional groups in organic matter pores and swelling clays. Inorganic controls on water adsorption are also observed in adsorbed water not tightly bound to the shale surface due to a high montmorillonite content in clay interlayers, and organic matter interaction with quartz with a negative relationship between the adsorbed water and the quartz content. Collectively, these findings indicate that CO2 migration in shale reservoirs could be inhibited by water that is distributed in potential CO2 adsorption sites within organic matter pores and montmorillonite.

The effect of vacuum preheating on the structure, electric, and optical properties of W-doped VO2 films prepared from thermal oxidation

Abstract: The effect of vacuum preheating on the structure, electric, and optical properties of the thermally oxidized W-doped VO2 films was studied. The results show that the film crystalline orientation and the inhomogeneous distribution of W increase after preheating. It was found that preheating at 700 °C and 800 °C reduces the metal-insulator transition (MIT) hysteresis because of the preferable orientation of the film along the (011) direction. The film preheated at 900 °C exhibits an undoped-like MIT due to a great increase in the inhomogeneous distribution of W. Preheating can affect the apparent activation energy of the cool-state resistances and increase the cool-state IR transmittances. By means of the Lorentz–Drude model, the conductance electron density (n c) and energy band gaps (E g) were obtained and discussed. It was shown that preheating can decrease the cool-state n c and affect the E g, indicating that the electronic band structure is changed by W doping.

Grain Boundary Elimination via Recrystallization-Assisted Vapor Deposition for Efficient and Stable Perovskite Solar Cells And Modules.

Abstract: Vapor deposition is a promising technology for the mass production of perovskite solar cells. However, the efficiencies of solar cells and modules based on vapor-deposited perovskites are significantly lower than those fabricated using the solution method. Emerging evidence suggests that large defects are generated during vapor deposition owing to a specific top-down crystallization mechanism. Herein, we present a hybrid vapor deposition method combined with solvent-assisted recrystallization for fabricating high-quality large-area perovskite films with low defect densities. We demonstrate that an intermediate phase can be formed at the grain boundaries, which induces the secondary growth of small grains into large ones. Consequently, perovskite films with substantially reduced grain boundaries and defect densities are fabricated. Results of temperature-dependent charge carrier dynamics show that the proposed method successfully suppressed all recombination reactions. We achieve champion efficiencies of 21.9% for small-area (0.16 cm2 ) cells and 19.9% for large-area (10.0 cm2 ) solar modules under AM 1.5 G irradiation. Moreover, the modules exhibit high operational stability, i.e., they retained more than 92% of their initial efficiencies after 200 h of continuous operation. This article is protected by copyright. All rights reserved.

Discriminatory Gate-Opening Effect in a Flexible Metal-Organic Framework for Inverse CO2 /C2 H2 Separation.

Abstract: Considering the significant application of acetylene (C2 H2 ) in the manufacturing and petrochemical industries, the selective capture of impurity carbon dioxide (CO2 ) is a crucial task and an enduring challenge. Here, a flexible metal-organic framework (Zn-DPNA) accompanied by a conformation change of the Me2 NH2 + ions in the framework is reported. The solvate-free framework provides a stepped adsorption isotherm and large hysteresis for C2 H2 , but type-I adsorption for CO2 . Owing to their uptakes difference before gate-opening pressure, Zn-DPNA demonstrated favorable inverse CO2 /C2 H2 separation. According to molecular simulation, the higher adsorption enthalpy of CO2 (43.1 kJ mol-1 ) is due to strong electrostatic interactions with Me2 NH2 + ions, which lock the hydrogen-bond network and narrow pores. Furthermore, the density contours and electrostatic potential verifies the middle of the cage in the large pore favors C2 H2 and repels CO2 , leading to the expansion of the narrow pore and further diffusion of C2 H2 . These results provide a new strategy that optimizes the desired dynamic behavior for one-step purification of C2 H2 .

Design and Fabrication of Room Temperature Electrically Pumped ZnO Nanowire Hybrid Plasmonic Lasers

Abstract: Plasmonic lasers have attracted much attention because they can break through the diffraction limit, but due to the large metal loss limitations, electrically driven plasmonic lasers mainly work at low temperatures to achieve sufficient gain. Therefore, we proposed electrically pumped nanowire plasmonic lasers at room temperature. Here, the metal/insulator/semiconductor (MIS) structure was applied to reduce the metal loss by separating the active area and the metal layer through the insulator. We illustrate the superiority of plasmonic laser performance by comparing plasmonic and photon lasers at room temperature. Our research provides some experimental basis for the realization of future optoelectronic integration.