1,543 results match your criteria power reaches

Stable flexible photodetector based on FePS/reduced graphene oxide heterostructure with significant enhancement in photoelectrochemical performance.

Nanotechnology 2021 Jul 22. Epub 2021 Jul 22.

School of Physics and Optoelectronics, Xiangtan University, School of Physics and Optoelectronics, Xiangtan University, Hunan 411105, PR China, Xiangtan, Hunan, 411105, CHINA.

Herein, FePS3/reduced graphene oxide (rGO) heterostructure has been prepared via a typical hydrothermal process, and flexible photodetectors based on hybrids have been subsequently fabricated. The photoresponse measurement results demonstrate that the photodetector exhibits obvious photoelectric conversion behavior without applied potential, indicating the device possesses capability of self-powered. In addition, the photocurrent density of as-fabricated photodetectors reaches up to 125 nA/cm2 under 90 mW/cm2 of illumination intensity without external power source, which is 5. Read More

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Influence of exposure conditions on helium transport and bubble growth in tungsten.

Sci Rep 2021 Jul 19;11(1):14681. Epub 2021 Jul 19.

CEA, IRFM, 13108, Saint-Paul-lez-Durance, France.

Helium diffusion, clustering and bubble nucleation and growth is modelled using the finite element method. The existing model from Faney et al. (Model Simul Mater Sci Eng 22:065010, 2018; Nucl Fusion 55:013014, 2015) is implemented with FEniCS and simplified in order to greatly reduce the number of equations. Read More

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A Meta-Analysis of Conductive and Strong Carbon Nanotube Materials.

Adv Mater 2021 Jul 19:e2008432. Epub 2021 Jul 19.

Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, UK.

A study of 1304 data points collated over 266 papers statistically evaluates the relationships between carbon nanotube (CNT) material characteristics, including: electrical, mechanical, and thermal properties; ampacity; density; purity; microstructure alignment; molecular dimensions and graphitic perfection; and doping. Compared to conductive polymers and graphitic intercalation compounds, which have exceeded the electrical conductivity of copper, CNT materials are currently one-sixth of copper's conductivity, mechanically on-par with synthetic or carbon fibers, and exceed all the other materials in terms of a multifunctional metric. Doped, aligned few-wall CNTs (FWCNTs) are the most superior CNT category; from this, the acid-spun fiber subset are the most conductive, and the subset of fibers directly spun from floating catalyst chemical vapor deposition are strongest on a weight basis. Read More

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The power of the future: Intergenerational income mobility and child maltreatment in the United States.

Child Abuse Negl 2021 Jul 12:105175. Epub 2021 Jul 12.

School of Social Work, University of Illinois at Urbana-Champaign, 1010 W. Nevada St., Urbana, IL 61801, United States of America.

Background: Recent research has shown that the likelihood of children experiencing intergenerational, upward income mobility depends on the community in which they are raised. Whether parents consider their children's economic chances in their parenting decisions, however, is not well understood.

Objective: To examine the relationship between county-level income mobility-distinct from income inequality and poverty-and child maltreatment. Read More

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High-precision passive stabilization of repetition rate for a mode-locked fiber laser based on optical pulse injection.

Opt Express 2021 Jun;29(13):20930-20940

We have proposed and implemented a novel scheme to obtain high-precision repetition rate stabilization for a polarization-maintaining mode-locked fiber laser. The essential technique lies in the periodic injection of electronically modulated optical pulses into a nonlinear amplifying loop mirror within the laser resonator. Thanks to the nonlinear cross-phase modulation effect, the injected pulses referenced to an external clock serves as a stable and precise timing trigger for an effective intensity modulator. Read More

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Laser regulation for variable color temperature lighting with low energy consumption by microlens arrays.

Appl Opt 2021 Jul;60(19):5652-5661

The construction of a smart city puts forward new requirements for lighting systems, such as variable color temperature adapting to environment and low energy consumption. We introduce a variable color temperature laser lighting system that produces uniform light with minimum energy. The color temperature is controlled by tri-color RGB diode lasers, and uniform lighting is achieved by microlens arrays. Read More

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Cobalt-Nickel Phosphate Composites for the All-Phosphate Asymmetric Supercapacitor and Oxygen Evolution Reaction.

ACS Appl Mater Interfaces 2021 Jul 13. Epub 2021 Jul 13.

School of Chemistry and Materials Science, Ludong University, Yantai 264025, PR China.

Recently, design of cost-effective multifunctional electromaterials for supercapacitors and oxygen evolution reaction (OER) and enhancing their functionalities have become an emphasis in energy storage and conversion. Herein, a series of cheap and functional phosphate composites with different ratios of cobalt and nickel are synthesized using a simple polyalcohol refluxing method, and their excellent capacity and OER properties are systematically studied. Notably, owing to the different major role of Co and Ni elements in the phosphate composites for capacity and OER, the optimal electroconductibility, structural adjustment, electrochemical active sites, and activities for capacity and OER are obtained from the composites with the different ratios of Co/Ni. Read More

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Plasma-Induced Heating Effects on Platinum Nanoparticle Size During Sputter Deposition Synthesis in Polymer and Ionic Liquid Substrates.

Langmuir 2021 Jul 12. Epub 2021 Jul 12.

Chemical Physics, Department of Physics, Chalmers University of Technology, Gothenburg 412 96, Sweden.

Nanoparticle catalyst materials are becoming ever more important in a sustainable future. Specifically, platinum (Pt) nanoparticles have relevance in catalysis, in particular, fuel cell technologies. Sputter deposition into liquid substrates has been shown to produce nanoparticles without the presence of air and other contaminants and the need for precursors. Read More

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Multiscale Coarse-Grained Model for the Stepping of Molecular Motors with Application to Kinesin.

J Chem Theory Comput 2021 Jul 12. Epub 2021 Jul 12.

Department of Chemistry, University of Texas at Austin, Austin, Texas 78705, United States.

Conventional kinesin, a motor protein that transports cargo within cells, walks by taking multiple steps toward the plus end of the microtubule (MT). While significant progress has been made in understanding the details of the walking mechanism of kinesin, there are many unresolved issues. From a computational perspective, a central challenge is the large size of the system, which limits the scope of time scales accessible in standard computer simulations. Read More

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Spatial representation of in-stream sediment phosphorus release combining channel network approaches and in-situ experiments.

Sci Total Environ 2021 Jun 29;795:148790. Epub 2021 Jun 29.

The James Hutton Institute, Craigiebuckler, Aberdeen AB158QH, UK.

Impairment of rivers by elevated phosphorus (P) concentration is an issue often studied at outlets of mesoscale catchments. Our objective was to evaluate within-catchment spatio-temporal processes along connected reaches to understand processes of internal P loading associated with sediment input, accumulations in channels and sediment-water column P exchange. Our overall hypothesis was that heterogeneous sediment residence within the channel of a 52 km mixed land cover catchment resulted in key zones for sediment-water P exchange. Read More

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Mass transfer from the rotor to the stator for improving the speed of the piezoelectric motor based on centrifugal force.

Rev Sci Instrum 2021 May;92(5):055008

School of Mechanical Engineering, Hefei University of Technology, Hefei 230009, China.

To improve the speed of a piezoelectric motor based on centrifugal force, a method is proposed on the basis of mass transfer from the rotor to the stator. Multi-degree-of-freedom vibration models are established before and after mass transfer. A mass of 150 g is transferred from the six-hole rotor to the stator. Read More

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Solar energy and regional coordination as a feasible alternative to large hydropower in Southeast Asia.

Nat Commun 2021 07 6;12(1):4159. Epub 2021 Jul 6.

Pillar of Engineering Systems and Design, Singapore University of Technology and Design, Singapore, Singapore.

Strategic dam planning and the deployment of decentralized renewable technologies are two elements of the same problem, yet normally addressed in isolation. Here, we show that an integrated view of the power system capacity expansion problem could have transformative effects for Southeast Asia's hydropower plans. We demonstrate that Thailand, Laos, and Cambodia have tangible opportunities for meeting projected electricity demand and CO emission targets with less hydropower than currently planned-options range from halting the construction of all dams in the Lower Mekong to building 82% of the planned ones. Read More

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An Electrostatic Self-Excited Resonator with Pre-Tension/Pre-Compression Constraint for Active Rotation Control.

Micromachines (Basel) 2021 Jun 1;12(6). Epub 2021 Jun 1.

School of Energy and Power Engineering, Beihang University, Beijing 100191, China.

We report a novel electrostatic self-excited resonator driven by DC voltage that achieves variable velocity-position characteristics via applying the pre-tension/pre-compression constraint. The resonator consists of a simply supported micro-beam, two plate electrodes, and two adjustable constraint bases, and it can be under pre-compression or pre-tension constraint by adjusting the distance between two constraint bases (when beam length > , the resonator is under pre-compression and when < , it is under pre-tension). The oscillating velocity of the beam reaches the maximum value in the position around electrodes under the pre-compression constraint and reaches the maximum value in the middle position between two electrodes under the pre-tension condition. Read More

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Analytical Modeling of a Doubly Clamped Flexible Piezoelectric Energy Harvester with Axial Excitation and Its Experimental Characterization.

Sensors (Basel) 2021 Jun 3;21(11). Epub 2021 Jun 3.

Institute of Intelligent Manufacturing and Control, Wuhan University of Technology, Wuhan 430063, China.

With the rapid development of wearable electronics, novel power solutions are required to adapt to flexible surfaces for widespread applications, thus flexible energy harvesters have been extensively studied for their flexibility and stretchability. However, poor power output and insufficient sensitivity to environmental changes limit its widespread application in engineering practice. A doubly clamped flexible piezoelectric energy harvester (FPEH) with axial excitation is therefore proposed for higher power output in a low-frequency vibration environment. Read More

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Influence of Riverbed Incision and Hydrological Evolution on Water Quality and Water Age Based on Numerical Simulation: A Case Study of the Minjiang Estuary.

Int J Environ Res Public Health 2021 06 6;18(11). Epub 2021 Jun 6.

School of Environmental and Municipal Engineering, North China University of Water Resources and Electric Power, 136 Jinshui East Road, Zhengzhou 450046, China.

In recent years, problems such as water quality deterioration, saltwater invasion, and low oxygen have appeared in estuaries all over the world. The Minjiang River in Fujian, as a typical tidal estuary area, is facing these thorny problems. In this paper, the effects of topography and hydrologic evolution on the water age and water quality of the lower reaches of the Minjiang River were simulated by building a hydrodynamic and water quality model. Read More

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Epileptic Seizure Detection on an Ultra-Low-Power Embedded RISC-V Processor Using a Convolutional Neural Network.

Biosensors (Basel) 2021 Jun 23;11(7). Epub 2021 Jun 23.

Multicomponent Materials, Institute for Material Science, Kiel University, 24143 Kiel, Germany.

The treatment of refractory epilepsy via closed-loop implantable devices that act on seizures either by drug release or electrostimulation is a highly attractive option. For such implantable medical devices, efficient and low energy consumption, small size, and efficient processing architectures are essential. To meet these requirements, epileptic seizure detection by analysis and classification of brain signals with a convolutional neural network (CNN) is an attractive approach. Read More

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ReStAC-UAV-Borne Real-Time SGM Stereo Optimized for Embedded ARM and CUDA Devices.

Sensors (Basel) 2021 Jun 7;21(11). Epub 2021 Jun 7.

Fraunhofer Center for Machine Learning, Fraunhofer Institute of Optronics, System Technologies and Image Exploitation (IOSB), 76131 Karlsruhe, Germany.

With the emergence of low-cost robotic systems, such as unmanned aerial vehicle, the importance of embedded high-performance image processing has increased. For a long time, FPGAs were the only processing hardware that were capable of high-performance computing, while at the same time preserving a low power consumption, essential for embedded systems. However, the recently increasing availability of embedded GPU-based systems, such as the NVIDIA Jetson series, comprised of an ARM CPU and a NVIDIA Tegra GPU, allows for massively parallel embedded computing on graphics hardware. Read More

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On-chip ultra-narrow-linewidth single-mode microlaser on lithium niobate on insulator.

Opt Lett 2021 Jul;46(13):3131-3134

We report an on-chip single-mode microlaser with a low threshold fabricated on erbium doped lithium-niobate-on-insulator (LNOI). The single-mode laser emission at 1550.5 nm wavelength is generated in a coupled microdisk via the inverse Vernier effect at room temperature, when pumping the resonator at 977. Read More

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Enhanced Piezoelectric Performance of Various Electrospun PVDF Nanofibers and Related Self-Powered Device Applications.

ACS Appl Mater Interfaces 2021 Jul 1;13(27):32242-32250. Epub 2021 Jul 1.

CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Micro-nano Energy and Sensor, Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing 101400, P. R. China.

The piezoelectric polymer poly(vinylidene fluoride) (PVDF) has been widely employed for energy harvesting or sensors. Its piezoelectricity originates from the unique crystal structure and the oriented electric dipoles. Generally, electrospinning (ES) is able to improve the crystallinity and piezoelectricity of PVDF. Read More

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Bandgap atomistic calculations on hydrogen-passivated GeSi nanocrystals.

Sci Rep 2021 Jun 30;11(1):13582. Epub 2021 Jun 30.

National Institute of Materials Physics, 405A Atomistilor Street, 077125, Magurele, Romania.

We present a detailed study regarding the bandgap dependence on diameter and composition of spherical Ge-rich GeSi nanocrystals (NCs). For this, we conducted a series of atomistic density functional theory (DFT) calculations on H-passivated NCs of Ge-rich GeSi random alloys, with Ge atomic concentration varied from 50 to 100% and diameters ranging from 1 to 4 nm. As a result of the dominant confinement effect in the DFT computations, a composition invariance of the line shape of the bandgap diameter dependence was found for the entire computation range, the curves being shifted for different Ge concentrations by ΔE(eV) = 0. Read More

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Eutrophication model driven by light and nutrients condition change in sluice-controlled river reaches.

Environ Sci Pollut Res Int 2021 Jun 29. Epub 2021 Jun 29.

School of Water Conservancy Science and Engineering, Zhengzhou University, Zhengzhou, 450001, China.

River eutrophication has become a challenging environmental problem worldwide because of the strong interference of anthropogenic activities and hydraulic structures. The driving mechanism of algae growth in sluice-controlled river reaches (SCRRs) is more complicated than that of natural rivers, because the operation mode of the sluices is an important influencing factor which changes the light and nutrient conditions of the water body. The main purpose of this study was to assess algal growth in SCRRs under external conditions and sluice regulation. Read More

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Spatial constraints in large-scale expansion of wind power plants.

Proc Natl Acad Sci U S A 2021 Jul;118(27)

Department of Global Ecology, Carnegie Institution for Science, Stanford, CA 94305.

When wind turbines are arranged in clusters, their performance is mutually affected, and their energy generation is reduced relative to what it would be if they were widely separated. Land-area power densities of small wind farms can exceed 10 W/m, and wakes are several rotor diameters in length. In contrast, large-scale wind farms have an upper-limit power density in the order of 1 W/m and wakes that can extend several tens of kilometers. Read More

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Modeling the effect of tumor compression on airflow dynamics in trachea using contact simulation and CFD analysis.

Comput Biol Med 2021 Jun 17;135:104574. Epub 2021 Jun 17.

Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH, USA. Electronic address:

Malignant central airway obstruction can cause severe breathing difficulty in a patient that requires surgical intervention or stent implantation to alleviate it. A predictive model to identify the onset of this event as the central airway is progressively compressed by tumor growth will be helpful for clinicians to plan for medical intervention. We present such a model to simulate tumor compression of the trachea and the resulting change in airflow dynamics to estimate the level of stenosis that will cause severe breathing difficulties. Read More

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Experimental energy improvement of a special design heat exchanger-based hybrid solar collector for a photovoltaic module square surface.

Environ Sci Pollut Res Int 2021 Jun 25. Epub 2021 Jun 25.

Unité de Recherche Appliquée en Energies Renouvelables, URAER, Centre de Développement des Energies Renouvelables, CDER, 47133, Ghardaïa, Algeria.

Solar cells convert a part of the solar irradiance into electrical energy, and the remaining produces heat, which can be converted as a thermal energy accumulated in the module. This conversion depends on the solar cells temperature. Since conversion efficiency is very low, 5-20%, this investigation proposes an optimal combination of a photovoltaic module with a specially designed heat exchanger in order to improve the conversion energy efficiency. Read More

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Effects of moisture content and tillage methods on creep properties of paddy soil.

PLoS One 2021 24;16(6):e0253623. Epub 2021 Jun 24.

College of Engineering, Huazhong Agricultural University, Wuhan, China.

The rheological properties parameters of paddy soil affect the interaction between the tillage tools and soil, thus influencing the operation quality and power consumption. In order to study the effects of tillage methods and moisture content on the rheological properties parameters of paddy soil in the middle and lower reaches of the Yangtze River, uniaxial compression creep tests of paddy soils with four moisture contents under no tillage (moisture contents: 26.71%, 24. Read More

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Surface illuminated interdigitated Ge-on-Si photodetector with high responsivity.

Opt Express 2021 May;29(11):16346-16361

To address the problem of traditional surface illuminated detectors being of low responsivity, this work proposes a large-size interdigitated "finger-type" germanium-on-silicon (Ge-on-Si) photodetector (PD) based on the surface illumination approach. For 1550 nm light with a surface incident power of -20 dBm at room temperature, the best responsivity of the PD achieved is ∼0.64 A/W at 0. Read More

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Voltage-Stabilizer-Grafted SiO Increases the Breakdown Voltage of the Cycloaliphatic Epoxy Resin.

ACS Omega 2021 Jun 31;6(23):15523-15531. Epub 2021 May 31.

Institute of Solid State Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui 230031, China.

Cycloaliphatic epoxy (CE) resin plays a vital role in insulation equipment due to its excellent insulation and processability. However, the insufficient ability of CE to confine electrons under high voltage often leads to an electric breakdown, which limits its wide applications in high-voltage insulation equipment. In this work, the interface effect of inorganic nano-SiO introduces deep traps to capture electrons, which is synergistic with the inherent ability of the voltage stabilizer -aminobenzoic acid (-ABA) to capture high-energy electrons through collision. Read More

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Sulfate Ions Induced Concave Porous S-N Co-Doped Carbon Confined FeC Nanoclusters with Fe-N Sites for Efficient Oxygen Reduction in Alkaline and Acid Media.

Small 2021 Jul 18;17(29):e2101001. Epub 2021 Jun 18.

State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, 430070, China.

To improve the catalytic activity of the catalysts, it is key to intensifying the intrinsic activity of active sites or increasing the exposure of accessible active sites. In this work, an efficient oxygen reduction electrocatalyst is designed that confines plentiful FeC nanoclusters with Fe-N sites in a concave porous S-N co-doped carbon matrix, readily accessible for the oxygen reduction reaction (ORR). Sulfate ions react with the carbon derived from ZIF-8 at high temperatures, leading to the shrinkage of the carbon framework and then forming a concave structure with abundant macropores and mesopores with S incorporation. Read More

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Power scaling of continuous-wave second harmonic generation in a MgO:PPLN ridge waveguide and the application to a compact wavelength conversion module.

Opt Lett 2021 Jun;46(12):2852-2855

The power scaling of continuous-wave (CW) second harmonic generation (SHG) in a MgO:periodically poled lithium niobite (PPLN) ridge waveguide is investigated. The nonlinear coefficient and propagation loss factors of the MgO:PPLN waveguide are verified for future reference. The MgO:PPLN waveguide structure is determined according to a practical fiber coupling configuration, as well as the theoretical model of output power characteristics. Read More

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Activated Carbon Nanotube Fiber Fabric as a High-Performance Flexible Electrode for Solid-State Supercapacitors.

ACS Appl Mater Interfaces 2021 Jun 11;13(24):28433-28441. Epub 2021 Jun 11.

State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, 2999 North Renmin Road, Shanghai 201620, China.

Owing to their features of excellent mechanical flexibility, high conductivity, and light weight, carbon-based fiber fabrics (CBFFs) are highly attractive as flexible electrodes for flexible solid-state supercapacitors (SCs). However, the achieved areal capacitance of most CBFFs is still unsatisfactory. Carbon nanotube fiber fabric (CNTFF) is a new kind of CBFF and could provide a potential alternative to high-performance flexible electrodes. Read More

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