6,303 research outputs found
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Modelling local amenities with online open-source data in a new spatial equilibrium model: Insights from applications for Beijing
This paper presents a new, general purpose method for modelling local
amenities in a city-level spatial equilibrium model with emerging data
sources. A log-form utility function is introduced to differentiate local
amenities from other hard-to-observe influences of locational choice for
residential and job location. In particular, we use the online open data of
schools and hospitals in Beijing to improve model parameterization and
calibration at high spatial resolution. The new local amenities element can improve the model’s fidelity on residence location choice by over 30%,
which is a step forward in decomposing the zonal attractiveness in spatial
equilibrium models. Moreover the local amenities component provides a
new interface for the spatial equilibrium models, where quantification of
the combined effects of urban land-use and local amenities policies can be simulated on a more consistent basis. The calibrated model of Beijing
shows that the coordination of local amenities provision has significant
impacts on the performance of urban spatial strategies. Uncoordinated local amenities provision may undermine or even overturn the long-term
plans for building a polycentric city region
Kondo correlation and spin-flip scattering in spin-dependent transport through a quantum dot coupled to ferromagnetic leads
We investigate the linear and nonlinear dc transport through an interacting
quantum dot connected to two ferromagnetic electrodes around Kondo regime with
spin-flip scattering in the dot. Using a slave-boson mean field approach for
the Anderson Hamiltonian having finite on-site Coulomb repulsion, we find that
a spin-flip scattering always depresses the Kondo correlation at arbitrary
polarization strength in both parallel and antiparallel alignment of the lead
magnetization and that it effectively reinforces the tunneling related
conductance in the antiparallel configuration. For systems deep in the Kondo
regime, the zero-bias single Kondo peak in the differential conductance is
split into two peaks by the intradot spin-flip scattering; while for systems
somewhat further from the Kondo center, the spin-flip process in the dot may
turn the zero-bias anomaly into a three-peak structure.Comment: 4 pages, 2 figure
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Structure-Induced Reversible Anionic Redox Activity in Na Layered Oxide Cathode
Anionic redox reaction (ARR) in lithium- and sodium-ion batteries is under hot discussion, mainly regarding how oxygen anion participates and to what extent oxygen can be reversibly oxidized and reduced. Here, a P3-type Na0.6[Li0.2Mn0.8]O2 with reversible capacity from pure ARR was studied. The interlayer O-O distance (peroxo-like O-O dimer, 2.506(3) Å), associated with oxidization of oxygen anions, was directly detected by using a neutron total scattering technique. Different from Li2RuO3 or Li2IrO3 with strong metal-oxygen (M-O) bonding, for P3-type Na0.6[Li0.2Mn0.8]O2 with relatively weak Mn-O covalent bonding, crystal structure factors might play an even more important role in stabilizing the oxidized species, as both Li and Mn ions are immobile in the structure and thus may inhibit the irreversible transformation of the oxidized species to O2 gas. Utilization of anionic redox reaction (ARR) on oxygen has been considered as an effective way to promote the charge-discharge capacity of the layered oxide cathodes for lithium- or sodium-ion batteries. The detailed mechanism of ARR, in particular how crystal structure affects and coordinates with the ARR, is not yet well understood. In the present work, a combination of X-ray and neutron total scattering measurements has been performed to study the structure of the prototype P3-type layered Na0.6[Li0.2Mn0.8]O2 with pure ARR. Unique structural characteristics, rather than prevailing knowledge of covalency of metal-oxygen, enable the stabilization of the crystal structure of Na0.6[Li0.2Mn0.8]O2 along with the ARR. This work suggests that reversible ARR can be manipulated by proper structure designs, thus to achieve high lithium or sodium storage in layered oxide cathodes. For P3-type Na0.6[Li0.2Mn0.8]O2 with relatively weak Mn-O covalent bonding, crystal structure factors play an important role in stabilizing the oxidized species, inhibiting the irreversible transformation of the oxidized species to O2 gas. The finding is important for better design of layered oxide positive materials with higher reversible capacity via the introduction of a reversible anionic redox reaction
Dominant Physicochemical Properties of SF6/N2 Thermal Plasmas with a Two-temperature Chemical Kinetic Model
It's increasingly clear that the existence of thermodynamic equilibrium is an exception rather than the role in SF6/N2 thermal plasmas. We intended to investigate the dominant physicochemical properties of SF6/N2 thermal plasmas at 4 atm from 12000 K to 1000 K with considering the thermal non-equilibrium. A two-temperature chemical kinetic model containing all the available reactions is developed. The temperature difference between the electron and the heavy species is defined as a function of the electron number density. The molar fractions of species are compared to the equilibrium composition predicted by Gibbs free energy minimization. By analyzing the main reactions in the generation and loss of a dominant species, the chemistry set is simplified and characterized by a few species and reactions. Then, the dominant physicochemical properties are captured and the computing time of complicated chemical kinetic model is dramatically shortened at the same time
A Primary Study on the Recording Method of Interior Decoration in Qing Dynasty – A Case Study of Interior Decoration of Jingfu Palace
The existing interior decoration of Qing Dynasty is the master of that of each dynasty, with its diversified forms and complicated
functions. As early as 1920s, the Rehabilitation Committee of Qing court recorded the interior furnishing in the Forbidden City by
using Chinese traditional documentary method. Today, along with the constantly updated techniques, the recording method for the
current situation of interior decoration has gradually developed from two-dimensional drawings into digital and comprehensive
record. However, the current research results are mostly limited to a single field. This paper takes the digital record and reproduction
about the current situation of interior decoration in Jingfu Palace in the Forbidden City as an example. Through the use of
photogrammetry, 3D laser scanning, virtual display and other technology and equipment at the forefront of architectural field, it
makes qualitative and quantitative record about the interior decoration inside Jingfu Palace. By combing with the interpretation of
historical documents, it restores the original design ideas hidden behind the current situation of interior decoration, so as to
summarize the best recording and reproducing method of interior decoration of Qing Dynasty
A-FABP mediates adaptive thermogenesis by promoting intracellular activation of thyroid hormones in brown adipocytes
The adipokine adipocyte fatty acid-binding protein (A-FABP) has been implicated in obesity-related cardio-metabolic complications. Here we show that A-FABP increases thermogenesis by promoting the conversion of T4 to T3 in brown adipocytes. We find that A-FABP levels are increased in both white (WAT) and brown (BAT) adipose tissues and the bloodstream in response to thermogenic stimuli. A-FABP knockout mice have reduced thermogenesis and whole-body energy expenditure after cold stress or after feeding a high-fat diet, which can be reversed by infusion of recombinant A-FABP. Mechanistically, A-FABP induces the expression of type-II iodothyronine deiodinase in BAT via inhibition of the nuclear receptor liver X receptor α, thereby leading to the conversion of thyroid hormone from its inactive form T4 to active T3. The thermogenic responses to T4 are abrogated in A-FABP KO mice, but enhanced by A-FABP. Thus, A-FABP acts as a physiological stimulator of BAT-mediated adaptive thermogenesis.published_or_final_versio
Effects of the filter-feeding benthic bivalve corbicula fluminea on plankton community and water quality in aquatic ecosystems: A mesocosm study
The influence of filter-feeding bivalves on plankton communities, nutrients, and water quality in a given aquatic ecosystem is so profound that they can be considered ecosystem engineers. In a 70-day mesocosm experiment, we tested the hypothesis that Corbicula fluminea would change plankton community structure by reducing small zooplankton and large phytoplankton and improve water quality by reducing nutrients. We monitored levels of nitrogen and phosphorus, organic suspended solids (OSS), and light at the sediment surface. Within the plankton, phytoplankton biomass (as Chl a, >0.45 μm), the biomass of microphytoplankton (>20 μm), nanophytoplankton (2–20 μm), picophytoplankton (0.2–2 μm), and zooplankton were determined. Compared with the controls, C. fluminea reduced the abundance of rotifers and the biomass of phytoplankton, and picophytoplankton, thereby modifying the plankton community structure. We did not observe reductions in TN and TP concentration, but OSS concentrations were reduced, and light intensity at the sediment surface was increased as a result of the improved water transparency. Our research shows that colonization by C. fluminea may modify plankton community structure and improve water quality of eutrophic shallow lakes, shedding further light on the ecological roles of filter-feeding bivalves in aquatic ecosystems
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