5 research outputs found
An Analysis on the Economic Benefit of Simplified Cultivation Technology for Longan in Hills and Mountains of Maoming City
No full textAccording to the characteristics of longan cultivated in the hill and mountain regions of Maoming City, this paper analyzed the economic benefit of the simplified cultivation techniques. With 15-year-old Chuliang longan trees as materials, the economic benefit of four kinds of simplified cultivation technologies was compared and analyzed. After nine years of continuous technological application, it was found that the input costs increased by 1.62%, and the output profits increased by 56.10%; in input costs, labor cost decreased by 41.33%, pesticide cost decreased by 24.19%, and fertilizer cost increased by 33.57%
Anomalous Neutron Nuclear-Magnetic Interference Spectroscopy
No full textThe electron-phonon interaction plays a critical role in materials
electrical, thermal, optical, and superconducting properties. However,
measuring the phonon mode-resolved electron-phonon interaction has been
challenging. Here we propose neutron-scattering-based Anomalous Neutron
nUclear-Magnetic Interference Spectroscopy (ANUBIS), where the co-existence of
neutron nuclear scattering and magnetic scattering leads to anomalous dynamical
structure factor under the presence of the electron-phonon interaction. Such
anomalous structure factor is linear in electron-phonon coupling constant at
the phonon wavevector, and is directly proportional to the momentum and
energy-resolved dielectric function. The experimental configuration can be
achieved using existing polarized inelastic neutron scattering setup, and an
order-of-magnitude estimate shows the viability to observe the anomalous
scattering signal is around to relative to phonon
scattering, which is achievable at emerging neutron facilities. Our proposal
offers an alternative neutron-based metrology to probe the crucial electronic
properties.Comment: 7 pages, 3 figure
Giant, non-perturbative tuning of light-matter interaction of embedded quantum dots in semiconducting matrices
No full textEmbedding quantum dots (QDs) in a solid-state matrix represents a promising hybrid platform that offers great flexibility and tunability. However, the lack of clear underlying designing principle and presence of large design space make the design process heavily relies on trial-and-error methods. Here we present a new principle that can drastically tailor the light-matter interaction of matrix by matrix-mediated QD interactions. We show that conducting matrices like P3HT can mediate a non-perturbative inter-QD interactions that lead to qualitatively distinct properties, including the enhanced carrier lifetime and enhanced binding energies with increased QD densities, which cannot be explained by conventional perturbative scattering theories and in sharp contrast to independent embedded QDs in an insulating matrix like PMMA. An effective quantum-field-theory is developed, showing qualitative agreement with experiments. Our study serves as a foundation for the predictive design of advanced hybrid materials aimed at optimizing functionalities
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Thickness-dependent polaron crossover in tellurene
No full textPolarons, quasiparticles from electron-phonon coupling, are crucial for material properties including high-temperature superconductivity and colossal magnetoresistance. However, scarce studies have investigated polaron formation in low-dimensional materials with phonon polarity and electronic structure transitions. In this work, we studied polarons of tellurene, composed of chiral Te chains. The frequency and linewidth of the A1 phonon, which becomes increasingly polar for thinner tellurene, change abruptly for thickness below 10 nanometers, where field-effect mobility drops rapidly. These phonon and transport signatures, combined with phonon polarity and band structure, suggest a crossover from large polarons in bulk tellurium to small polarons in few-layer tellurene. Effective field theory considering phonon renormalization in the small-polaron regime semiquantitatively reproduces the phonon hardening and broadening effects. This polaron crossover stems from the quasi-one-dimensional nature of tellurene, where modulation of interchain distance reduces dielectric screening and promotes electron-phonon coupling. Our work provides valuable insights into the influence of polarons on phononic, electronic, and structural properties in low-dimensional materials
Overview of the recent experimental research on the J-TEXT tokamak
No full textThe J-TEXT capability is enhanced compared to two years ago with several upgrades of its diagnostics and the increase of electron cyclotron resonance heating (ECRH) power to 1 MW. With the application of electron cyclotron wave (ECW), the ECW assisted plasma startup is achieved; the tearing mode is suppressed; the toroidal injection of 300 kW ECW drives around 24 kA current; fast electrons are generated with toroidal injected ECW and the runaway current conversion efficiency increases with ECRH power. The mode coupling between 2/1 and 3/1 modes are extensively studied. The coupled 2/1 and 3/1 modes usually lead to major disruption. Their coupling can be either suppressed or avoided by external resonant magnetic perturbation fields and hence avoids the major disruption. It is also found that the 2/1 threshold of external field is significantly reduced by a pre-excited 3/1 mode, which can be either a locked island or an external kink mode. The disruption control is studied by developing prediction methods capable of cross tokamak application and by new mitigation methods, such as the biased electrode or electromagnetic pellet injector. The high-density operation and related disruptions are studied from various aspects. Approaching the density limit, the collapse of the edge shear layer is observed and such collapse can be prevented by applying edge biasing, leading to an increased density limit. The density limit is also observed to increase, if the plasma is operated in the poloidal divertor configuration or the plasma purity is increased by increasing the pre-filled gas pressure or ECRH power during the start-up phase
