144,477 research outputs found
POTATO CONSUMPTION IN CANADA: IS IT BECOMING A NORMAL GOOD?
Food Consumption/Nutrition/Food Safety,
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Linking human-building interactions in shared offices with personality traits
Occupant behavior influences office building energy performance. The level of human-building interactions (HBIs) in shared offices strongly influences building energy use and occupant well-being. This study explored the link between occupant personality types and their behaviors of sharing energy and environment control systems and interactions with their colleagues. Inspired by the Five-Factor Model (FFM), we classified HBI behaviors into four dimensions: willingness to share control, knowledge of control, group decision behavior, and adaptive strategies. These four variables can be mapped to the four personality traits proposed by the FFM: agreeableness, openness, extraversion, and conscientiousness. Our cluster analysis identified six behavioral patterns: average (17.7%), reserved (15.3%), environmentally friendly (16.6%), role model (24.2%), self-centered (17.2%), and mechanist (9.0%). We further applied association rules, a widely utilized machine learning technique, to discover how demographics, building-related contextual factors, and perception-attitudinal factors influence HBI behaviors. Country, control feature accessibility, and group dynamics were found to be the three most influential factors that determine occupants’ HBI behaviors. The study provides insights about building design and operation, as well as policy to promote socially and environmentally desirable HBI behaviors in a shared office environment
High efficiency single quantum well graded-index separate-confinement heterostructure lasers fabricated with MeV oxygen ion implantation
Single quantum well AlGaAs/GaAs graded-index separate-confinement heterostructure lasers have been fabricated using MeV oxygen ion implantation plus optimized subsequent thermal annealing. A high differential quantum efficiency of 85% has been obtained in a 360-µm-long and 10-µm-wide stripe geometry device. The results have also demonstrated that excellent electrical isolation (breakdown voltage of over 30 V) and low threshold currents (22 mA) can be obtained with MeV oxygen ion isolation. It is suggested that oxygen ion implantation induced selective carrier compensation and compositional disordering in the quantum well region as well as radiation-induced lattice disordering in AlxGa1–xAs/GaAs may be mostly responsible for the buried layer modification in this fabrication process
Enhanced collimated GeV monoenergetic ion acceleration from a shaped foil target irradiated by a circularly polarized laser pulse
Using multi-dimensional particle-in-cell (PIC) simulations we study ion
acceleration from a foil irradiated by a circularly polarized laser pulse at
1022W/cm^2 intensity. When the foil is shaped initially in the transverse
direction to match the laser intensity profile, the center part of the target
can be uniformly accelerated for a longer time compared to a usual flat target.
Target deformation and undesirable plasma heating are effectively suppressed.
The final energy spectrum of the accelerated ion beam is improved dramatically.
Collimated GeV quasi-mono-energetic ion beams carrying as much as 18% of the
laser energy are observed in multi-dimensional simulations. Radiation damping
effects are also checked in the simulations.Comment: 4 pages, 4 figure
Optical spectroscopy study on single crystalline LaFeAsO
Millimeter-sized single crystals of LaFeAsO were grown from NaAs flux and the
in-plane optical properties were studied over a wide frequency range. A sizable
electronic correlation effect was indicated from the analysis of the
free-carrier spectral weight. With decreasing temperature from 300 K, we
observed a continuous suppression of the spectral weight near 0.6 eV. But a
spin-density-wave gap formation at lower energy scale was seen only in the
broken-symmetry state. We elaborate that both the itinerancy and local spin
interactions of Fe\emph{3d} electrons are present for the FeAs-based systems;
however, the establishment of the long-range magnetic order at low temperature
has a dominantly itinerant origin.Comment: 4 figures, 5 page
Global analysis of quadrupole shape invariants based on covariant energy density functionals
Coexistence of different geometric shapes at low energies presents a
universal structure phenomenon that occurs over the entire chart of nuclides.
Studies of the shape coexistence are important for understanding the
microscopic origin of collectivity and modifications of shell structure in
exotic nuclei far from stability. The aim of this work is to provide a
systematic analysis of characteristic signatures of coexisting nuclear shapes
in different mass regions, using a global self-consistent theoretical method
based on universal energy density functionals and the quadrupole collective
model. The low-energy excitation spectrum and quadrupole shape invariants of
the two lowest states of even-even nuclei are obtained as solutions of
a five-dimensional collective Hamiltonian (5DCH) model, with parameters
determined by constrained self-consistent mean-field calculations based on the
relativistic energy density functional PC-PK1, and a finite-range pairing
interaction. The theoretical excitation energies of the states: ,
, , , , as well as the
values, are in very good agreement with the corresponding experimental values
for 621 even-even nuclei. Quadrupole shape invariants have been implemented to
investigate shape coexistence, and the distribution of possible
shape-coexisting nuclei is consistent with results obtained in recent
theoretical studies and available data. The present analysis has shown that,
when based on a universal and consistent microscopic framework of nuclear
density functionals, shape invariants provide distinct indicators and reliable
predictions for the occurrence of low-energy coexisting shapes. This method is
particularly useful for studies of shape coexistence in regions far from
stability where few data are available.Comment: 13 pages, 3 figures, accepted for publication in Phys. Rev.
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