187 research outputs found
Mechanism of environmental factors regulating water consumption of Larix gmelinii forests
No full textPurpose: To examine and understand mechanisms of hydrological functions and water transport of Larix gmelinii ecosystems, we quantified water consumption (ET), including soil evaporation (E) and vegetation transpiration (T), and the role of environmental factors. Methods: Stable isotope technology was utilized to make high-frequency in situ observations on the oxygen isotope composition (δ18O) of water vapor from six vertical heights (0.1–40 m above ground) in the cold-temperate Larix gmelinii forests in Northeast China. The dynamics of δ18O and its responses to environmental factors were detected during the water consumption process. One-way analysis of variance, independent-samples t test, and path analysis were used in data analysis. Results: The oxygen isotope composition of water vapor decreased with increasing vertical height. Contribution of T to ET varied between 79 and 96%. Values of δ18O in water vapor produced by E (δ18OE) corresponded most closely to water content at 10-cm soil depth (SWC10), while those produced by T (δ18OT) were associated with different environmental factors: air temperature (Ta) for the shrub-based stand, relative humidity (RH) for the herb-based stand, and temperature at 5-cm soil depth (Ts5) for the moss-based stand. Solar radiation (SR) was the dominant factor controlling the δ18O of water vapor produced by ET (δ18OET). Conclusion: Transpiration is the primary means of ecosystem water loss in Larix gmelinii forests. Overall, water loss from T of shrub-based Larix gmelinii stand is greater than those of herb-based and moss-based stands. Meteorological and soil factors mutually affect ecosystem water loss to atmosphere.No Full Tex
Highly Sensitive Low-Bandgap Perovskite Photodetectors with Response from Ultraviolet to the Near-Infrared Region
No full textPhysicochemical and biological properties of a novel injectable polyurethane system for root canal filling
No full textJian Wang,1 Yi Zuo,1 Minghui Zhao,1 Jiaxing Jiang,1 Yi Man,2 Jun Wu,3 Yunjiu Hu,3 Changlei Liu,4 Yubao Li,1 Jidong Li11Research Center for Nano-Biomaterials, Analytical and Testing Center, Sichuan University, Chengdu, Sichuan, People’s Republic of China; 2College of Stomatology, Sichuan University, Chengdu, Sichuan, People’s Republic of China; 3Department of Orthopedics, Chongqing Medical University, Chongqing, People’s Republic of China; 4College of Chemistry, Sichuan University, Chengdu, Sichuan, People’s Republic of ChinaAbstract: A root canal sealer with antibacterial activity can be efficacious in preventing reinfection that results from residual microorganisms and/or the leakage of microorganisms. In the present study, a series of injectable, self-curing polyurethane (PU)-based antibacterial sealers with different concentrations of silver phosphate (Ag3PO4) were fabricated. Subsequently, their physicochemical properties, antibacterial abilities, and preliminary cytocompatibilities were evaluated. The results indicated that the fabricated PU-based sealers can achieve a high conversion rate in a short amount of time. More than 95% of the isocyanate group of PU sealers with 3 wt% (PU3) and 5 wt% (PU5) concentrations of Ag3PO4 were included in the curing reaction after 7 hours. With the exception of those for film thickness for PU5, the results of setting time, film thickness, and solubility were able to meet the requirements of the International Organization for Standardization. The antibacterial tests showed that PU3 and PU5 exhibit stronger antimicrobial effects than that achieved with 1 wt% Ag3PO4 (PU1) and AH Plus (positive control) against Streptococcus mutans. The cytocompatibility evaluation revealed that the PU1 and PU3 sealers possess good cytocompatibility and low cytotoxicity. These results demonstrate that the PU3 sealer offers good physicochemical and antimicrobial properties along with cytocompatibility, which may hold great application potential in the field of root canal fillings.Keywords: root canal sealer, polyurethane, silver phosphate, antibacterial properties, direct contact tes
Photonics-aided frequency agile microwave generation based on coupled opto-electronic oscillators
No full textExistence and Global Stability Analysis of Almost Periodic Solutions for Cohen-Grossberg Neural Networks
No full textStudy on the Sustainable use of Regional Groundwater Resources
No full textWater resources have become a major factor limiting the sustainable development of China’s economy and society, and at the same time China’s water resources are developed and utilized in a relatively sloppy manner, China is facing multiple pressures of population, resources and environment, and the problems of water shortage, water environment deterioration and flood disaster prevention are becoming increasingly prominent. The rapid development of economic and social demand for water resources is increasing, and the people’s desire to improve the ecology and environment is becoming more and more urgent. How to fully consider the sustainable use of water resources, effectively solve the contradiction between water demand and supply, development and protection, improve the level of planning and scientific decision-making, promote economic development and water carrying capacity to adapt to accelerate the transformation of economic growth and structural adjustment is of great importance
An energy conservation and environmental improvement solution-ultra-capacitor/battery hybrid power source for vehicular applications
No full textA Self-Stabilizing Phase Decoder for Quantum Key Distribution
No full textSelf-stabilization quantum key distribution (QKD) systems are often based on the Faraday magneto-optic effect such as “plug and play” QKD systems and Faraday–Michelson QKD systems. In this article, we propose a new anti-quantum-channel disturbance decoder for QKD without magneto-optic devices, which can be a benefit for the photonic integration and applications in magnetic environments. The decoder is based on a quarter-wave plate reflector–Michelson (Q–M) interferometer, with which the QKD system can be free of polarization disturbance caused by quantum channel and optical devices in the system. The theoretical analysis indicates that the Q–M interferometer is immune to polarization-induced signal fading, where the operator of the Q–M interferometer corresponding to Pauli Matrix σ2 makes it satisfy the anti-disturbance condition naturally. A Q–M interferometer based time-bin phase encoding QKD setup is demonstrated, and the experimental results show that the QKD setup works stably with a low quantum bit error rate about 1.3% for 10 h over 60.6 km standard telecommunication optical fiber
Heterojunction Perovskite Solar Cells: Opto-Electro-Thermal Physics, Modeling, and Experiment
No full textOrganic–inorganic
heterojunction perovskite solar cell (PSC)
is promising for low-cost and high-performance photovoltaics. To further
promote the performance of PSCs, understanding and controlling the
underneath photoconversion mechanisms are highly necessary. Here,
we present a comprehensive opto-electro-thermal (OET) study on the
heterojunction PSCs by quantitatively addressing the coupled optical,
carrier transport, and thermodynamic behaviors within the device.
With achieving a good agreement with the experiment, we theoretically
explore the thermodynamic mechanisms involving the energy conversions
and focus especially on the origins of the various energy losses in
PSCs. We summarize six categories of microscopic heat conversion processes
in the heterojunction PSC, where the Joule and Peltier heats can be
defined as the intrinsic losses in PSCs. Moreover, we also discuss
the possible manipulation methods to decrease the energy losses, for
example, by tailoring the doping concentration and energy-level alignment.
An exemplified OET optimization is also presented, which predicts
that the PCE of the fabricated PSC can be enhanced from 21.37% to
23.84%
Keypoint-Based Robotic Grasp Detection Scheme in Multi-Object Scenes
No full textRobot grasping is an important direction in intelligent robots. However, how to help robots grasp specific objects in multi-object scenes is still a challenging problem. In recent years, due to the powerful feature extraction capabilities of convolutional neural networks (CNN), various algorithms based on convolutional neural networks have been proposed to solve the problem of grasp detection. Different from anchor-based grasp detection algorithms, in this paper, we propose a keypoint-based scheme to solve this problem. We model an object or a grasp as a single point-the center point of its bounding box. The detector uses keypoint estimation to find the center point and regress to all other object attributes such as size, direction, etc. Experimental results demonstrate that the accuracy of this method is 74.3% in the multi-object grasp dataset VMRD, and the performance on the single-object scene Cornell dataset is competitive with the current state-of-the-art grasp detection algorithm. Robot experiments demonstrate that this method can help robots grasp the target in single-object and multi-object scenes with overall success rates of 94% and 87%, respectively
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