18,392 research outputs found
Power generation expansion planning model towards low-carbon economy and its application in china
Climate change poses a huge threat to human welfare. Hence, developing a low-carbon economy has become a prevailing and inevitable trend. Decarbonization of power generation, especially converting the current power mix into a low-carbon structure, will be a critical option for CO2 emission mitigation. In this paper, an integrated power generation expansion (PGE) planning model towards low-carbon economy is proposed, which properly integrates and formulates the impacts of various low-carbon factors on PGE models. In order to adapt to the characteristics of PGE models based on low-carbon scenario, a compromised modeling approach is presented, which reasonably decreases complexities of the model, while properly keeping the significant elements and maintaining moderate precision degree. In order to illustrate the proposed model and approach, a numerical case is studied based on the background of China's power sector, making decisions on the optimal PGE plans and revealing the prospects and potentials for CO2 emission reduction. © 2010 IEEE.published_or_final_versio
Momentum Distribution of Near-Zero-Energy Photoelectrons in the Strong-Field Tunneling Ionization in the Long Wavelength Limit
We investigate the ionization dynamics of Argon atoms irradiated by an
ultrashort intense laser of a wavelength up to 3100 nm, addressing the momentum
distribution of the photoelectrons with near-zero-energy. We find a surprising
accumulation in the momentum distribution corresponding to meV energy and a
\textquotedblleft V"-like structure at the slightly larger transverse momenta.
Semiclassical simulations indicate the crucial role of the Coulomb attraction
between the escaping electron and the remaining ion at extremely large
distance. Tracing back classical trajectories, we find the tunneling electrons
born in a certain window of the field phase and transverse velocity are
responsible for the striking accumulation. Our theoretical results are
consistent with recent meV-resolved high-precision measurements.Comment: 5 pages, 4 figure
The use of artificial neural networks in the motor program
Though it is commonly assumed that the brain creates 'motor programs' which store the information essential to perform a motor skill, little direct evidence exists for such motor programs. Electromyography (EMG) provides a look into the motoneurons - level of a movement by measuring the electrical activity in relation to the muscle's involvement in the movement In this paper, artificial neural networks (ANNs) were applied to define the temporal patterns of EMG activity used by normal subjects in performing step-tracking tasks, and how such patterns change with practice. Our results demonstrate that ANNs could be trained to detect the input-output relationship between muscles' onset times and reaction times, and provided evidence to support the existence of a motor program.published_or_final_versio
Alterations of coronary perfusion pressure and cardiac contraction during lipopolysaccharide challenge
In the present study, we used the Langendorff technique to evaluate the involvement of endothelin-1 (ET-I) and nitric oxide (NO) in coronary vasoconstriction and myocardial depression in hearts isolated from lipopolysaccharide (LPS)-treated rats. Coronary perfusion pressure (CPP) increased markedly in hearts from LPS -treated rats. Pretreatment with BQ-123, an ET-1 type A receptor antagonist, significantly reduced the increase in CPP induced by LPS. LPS induced a marked decrease in left ventricular developed pressure, the product of left ventricular developed pressure and heart rate, as well as the maximal rate of rise/fall of left ventricular pressure. Pretreatment with BQ-123 partially reversed the LPS-induced cardiac depression. Administration of BQ-123 and AMG, an inhibitor of iNOS, prior to LPS challenge significantly blocked the negative inotropic effect. These results suggest that ET-1 augments the NO-mediated cardiac contractile depression induced by LPS and the accompanying increase in coronary resistance.published_or_final_versio
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