1,043 research outputs found
Chinese and North American Culture: a New Perspective in Linguistics Studies
We explored the two cultures in the two countries. There has been discussed on Chinese culture and North American culture. Chinese language, ceramics, architecture, music, dance, literature, martial arts, cuisine, visual arts, philosophy, business etiquette, religion, politics, and history have global influence, while its traditions and festivals are also celebrated, instilled, and practiced by people around the world. The culture of North America refers to the arts and other manifestations of human activities and achievements from the continent of North America. The American way of life or simply the American way is the unique lifestyle of the people of the United States of America. It refers to a nationalist ethos that adheres to the principle of life, liberty and the pursuit of happiness
Optimization on fresh outdoor air ratio of air conditioning system with stratum ventilation for both targeted indoor air quality and maximal energy saving
Stratum ventilation can energy efficiently provide good inhaled indoor air quality with a proper operation (e.g., fresh outdoor air ratio). However, the non-uniform CO2 distribution in a stratum-ventilated room challenges the provision of targeted indoor air quality. This study proposes an optimization on the fresh outdoor air ratio of stratum ventilation for both the targeted indoor air quality and maximal energy saving. A model of CO2 concentration in the breathing zone is developed by coupling CO2 removal efficiency in the breathing zone and mass conservation laws. With the developed model, the ventilation parameters corresponding to different fresh outdoor air ratios are quantified to achieve the targeted indoor air quality (i.e., targeted CO2 concentration in the breathing zone). Using the fresh outdoor air ratios and corresponding ventilation parameters as inputs, energy performance evaluations of the air conditioning system are conducted by building energy simulations. The fresh outdoor air ratio with the minimal energy consumption is determined as the optimal one. Experiments show that the mean absolute error of the developed model of CO2 concentration in the breathing zone is 1.9%. The effectiveness of the proposed optimization is demonstrated using TRNSYS that the energy consumption of the air conditioning system with stratum ventilation is reduced by 6.4% while achieving the targeted indoor air quality. The proposed optimization is also promising for other ventilation modes for targeted indoor air quality and improved energy efficiency
Heat removal efficiency of stratum ventilation for air-side modulation
Stratum ventilation has significant thermal non-uniformity between the occupied and upper zones. Although the non-uniformity benefits indoor air quality and energy efficiency, it increases complexities and difficulties in the air-side modulation. In this study, a heat removal efficiency (HRE) model is first established and validated, and then used for the air-side modulation. The HRE model proposed is a function of supply air temperature, supply airflow rate and cooling load. The HRE model proposed has been proven to be applicable to stratum ventilation and displacement ventilation for different room geometries and air terminal configurations, with errors generally within ±5% and a mean absolute error less than 4% for thirty-three experimental cases and five simulated cases. Investigations into the air-side modulation with the proposed HRE model reveal that for both the typical stratum-ventilated classroom and office, the variable-air-volume system can serve a wider range of cooling load than the constant-air-volume system. The assumption of a constant HRE used in the conventional method could lead to errors in the room temperature prediction up to ±1.3 °C, thus the proposed HRE model is important to the air-side modulation for thermal comfort. An air-side modulation method is proposed based on the HRE model to maximize the HRE for improving energy efficiency while maintaining thermal comfort. Results show that the HRE model based air-side modulation can improve the energy efficiency of stratum ventilation up to 67.3%. The HRE model based air-side modulation is also promising for displacement ventilation
Rugged Metropolis Sampling with Simultaneous Updating of Two Dynamical Variables
The Rugged Metropolis (RM) algorithm is a biased updating scheme, which aims
at directly hitting the most likely configurations in a rugged free energy
landscape. Details of the one-variable (RM) implementation of this
algorithm are presented. This is followed by an extension to simultaneous
updating of two dynamical variables (RM). In a test with Met-Enkephalin in
vacuum RM improves conventional Metropolis simulations by a factor of about
four. Correlations between three or more dihedral angles appear to prevent
larger improvements at low temperatures. We also investigate a multi-hit
Metropolis scheme, which spends more CPU time on variables with large
autocorrelation times.Comment: 8 pages, 5 figures. Revisions after referee reports. Additional
simulations for temperatures down to 220
A new tow-parameter integrable model of strongly correlated electrons with quantum superalgebra symmetry
A new two-parameter integrable model with quantum superalgebra
symmetry is proposed, which is an eight-state electron model with correlated
single-particle and pair hoppings as well as uncorrelated triple-particle
hopping. The model is solved and the Bethe ansatz equations are obtained.Comment: 6 pages, RevTe
Constructing a multi-leveled ecological security pattern for improving ecosystem connectivity in the Asian Water Tower region
Serious ecological crises have emerged in the Asian Water Tower region (17 countries centered on the Qinghai-Tibetan Plateau), making it a major priority and challenge for Asian and even global ecological conservation efforts. Constructing a multi-leveled ecological security pattern (ESP) based on the synergies among multiple ecosystem services (ESs) for this region can enhance the structural integrity, functional stability, and spatial connectivity of ecosystems. Therefore, based on a series of GIS spatial analysis methods, the minimum cumulative resistance model, and the analytic hierarchy process, this study measured the importance of five key ESs focused by Sustainable Development Goal 15 (including water conservation, carbon sequestration, sand fixation, soil conservation, and biodiversity conservation); and took fishnet scale as data calculation unit to construct a hierarchical ESP (including three levels of ecological sources and corridors) to provide evidence-based support for identifying and prioritizing synergistic conservation actions across scales (regions, nations, and basins). Overall, the ESP included a total of 534 sources and 656 corridors. Some key conservation obstacles in the region (e.g., edge effects and several human activities) and corresponding priority actions are provided, such as integrating the ESPs into long-term planning, enhancing the conservation and the restoration of both the extent and the quality of forests (e.g., increasing tree species richness), and increasing collaboration across scales for resource mobilization and synergistic land use
Multi-Band Exotic Superconductivity in the New Superconductor Bi4O4S3
Resistivity, Hall effect and magnetization have been investigated on the new
superconductor Bi4O4S3. A weak insulating behavior has been induced in the
normal state when the superconductivity is suppressed. Hall effect measurements
illustrate clearly a multiband feature dominated by electron charge carriers,
which is further supported by the magnetoresistance data. Interestingly, a kink
appears on the temperature dependence of resistivity at about 4 K at all high
magnetic fields when the bulk superconductivity is completely suppressed. This
kink can be well traced back to the upper critical field Hc2(T) in the low
field region, and is explained as the possible evidence of residual Cooper
pairs on the one dimensional chains.Comment: 5 pages, 5 figure
Algebraic Bethe Ansatz for Integrable Extended Hubbard Models Arising from Supersymmetric Group Solutions
Integrable extended Hubbard models arising from symmetric group solutions are
examined in the framework of the graded Quantum Inverse Scattering Method. The
Bethe ansatz equations for all these models are derived by using the algebraic
Bethe ansatz method.Comment: 15 pages, RevTex, No figures, to be published in J. Phys.
GeV antiproton/gamma-ray excesses and the -boson mass anomaly: three faces of GeV dark matter particle?
For the newly discovered -boson mass anomaly, one of the simplest dark
matter (DM) models that can account for the anomaly without violating other
astrophysical/experimental constraints is the inert two Higgs doublet model, in
which the DM mass () is found to be within GeV. In this
model, the annihilation of DM via and would
produce antiprotons and gamma rays, and may account for the excesses identified
previously in both particles. Motivated by this, we re-analyze the AMS-02
antiproton and Fermi-LAT Galactic center gamma-ray data. For the antiproton
analysis, the novel treatment is the inclusion of the charge-sign-dependent
three-dimensional solar modulation model as constrained by the time-dependent
proton data. We find that the excess of antiprotons is more distinct than
previous results based on the force-field solar modulation model. The
interpretation of this excess as the annihilation of () requires a DM mass of () GeV and a
velocity-averaged cross section of . As for the
-ray data analysis, rather than adopting the widely-used spatial
template fitting, we employ an orthogonal approach with a data-driven spectral
template analysis. The fitting to the GeV -ray excess yields DM model
parameters overlapped with those to fit the antiproton excess via the
channel. The consistency of the DM particle properties required to account for
the -boson mass anomaly, the GeV antiproton excess, and the GeV -ray
excess suggest a common origin of them.Comment: 8 page
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