30 research outputs found
Slip Control of Electric Vehicle Based on Tire-Road Friction Coefficient Estimation
The real-time change of tire-road friction coefficient is one of the important factors that influence vehicle safety performance. Besides, the vehicle wheels’ locking up has become an important issue. In order to solve these problems, this paper comes up with a novel slip control of electric vehicle (EV) based on tire-road friction coefficient estimation. First and foremost, a novel method is proposed to estimate the tire-road friction coefficient, and then the reference slip ratio is determined based on the estimation results. Finally, with the reference slip ratio, a slip control based on model predictive control (MPC) is designed to prevent the vehicle wheels from locking up. In this regard, the proposed controller guarantees the optimal braking torque on each wheel by individually controlling the slip ratio of each tire within the stable zone. Theoretical analyses and simulation show that the proposed controller is effective for better braking performance
Chaplygin inflation in loop quantum cosmology
In this paper we discuss the inflationary universe in the context of a
Chaplygin gas equation of state within the framework of the effective theory of
loop quantum cosmology. Under the slow-roll approximation, we calculate the
primordial perturbations for this model. We give the general expressions of the
scalar spectral index, its running, and the tensor-to-scalar ratio, etc. For
the chaotic inflation with a quadratic potential, using the WMAP 5-year
results, we determine the parameters of the Chaplygin inflation model in loop
quantum cosmology. The results are consistent with the WMAP observations.Comment: 6 pages, accepted for publication in Mod. Phys. Lett.
A de novo Genome of a Chinese Radish Cultivar
AbstractHere, we report a high-quality draft genome of a Chinese radish (Raphanus sativus) cultivar. This draft contains 387.73Mb of assembled scaffolds, 83.93% of the scaffolds were anchored onto nine pseudochromosomes and 95.09% of 43 240 protein-coding genes were functionally annotated. 184.75Mb (47.65%) of repeat sequences was identified in the assembled genome. By comparative analyses of the radish genome against 10 other plant genomes, 2 275 genes in 780 gene families were found unique to R. sativus. This genome is a good reference for genomic study and of great value for genetic improvement of radish
Cosmic age problem revisited in the holographic dark energy model
Because of an old quasar APM 08279+5255 at , some dark energy models
face the challenge of the cosmic age problem. It has been shown by Wei and
Zhang [Phys. Rev. D {\bf 76}, 063003 (2007)] that the holographic dark energy
model is also troubled with such a cosmic age problem. In order to accommodate
this old quasar and solve the age problem, we propose in this Letter to
consider the interacting holographic dark energy in a non-flat universe. We
show that the cosmic age problem can be eliminated when the interaction and
spatial curvature are both involved in the holographic dark energy model.Comment: 7 pages, 3 figures; v2: typos corrected, version for publication in
Phys.Lett.B; v3: typos in eqs (17,18) correcte
Interacting model of new agegraphic dark energy: observational constraints and age problem
Many dark energy models fail to pass the cosmic age test because of the old
quasar APM 08279+5255 at redshift , the CDM model and
holographic dark energy models being no exception. In this paper, we focus on
the topic of age problem in the new agegraphic dark energy (NADE) model. We
determine the age of the universe in the NADE model by fitting the
observational data, including type Ia supernovae (SNIa), baryon acoustic
oscillations (BAO) and the cosmic microwave background (CMB). We find that the
NADE model also faces the challenge of the age problem caused by the old quasar
APM 08279+5255. In order to overcome such a difficulty, we consider the
possible interaction between dark energy and dark matter. We show that this
quasar can be successfully accommodated in the interacting new agegraphic dark
energy (INADE) model at the level under the current observational
constraints.Comment: 12 pages, 5 figures; typos corrected; version for publication in
SCIENCE CHINA Physics, Mechanics & Astronom
Efficient tuning of surface nickel species of the Ni-phyllosilicate catalyst for the hydrogenation of maleic anhydride
The rational design of catalyst is vital in the hydrogenation of maleic anhydride (MA) to chemicals, for its special construction with one C=C bond and two C=O bonds. Herein, the catalyst with nickel nanoparticles (NPs), inlaid nickel phyllosilicate (Ni-PS) featured with proper Ni
0
and assembled Lewis acid sites, is proposed for the efficient hydrogenation of MA to succinic anhydride (SA) and γ-butyrolactone (GBL). The remarkable efficiency is attributed to the synergistic effect between the surface Ni
0
and the Lewis acid sites induced from partially reduced Ni and coordinatively unsaturated Ni(II) in Ni-PS. The acid sites adsorb and activate the C=C and C=O groups, whereas the Ni
0
facilitates the H
2
decomposition. In situ XPS demonstrated that the ratio of surface Ni
0
and Lewis acid sites can be modulated effectively by changing the Ni/Si molar ratio in the catalysts, and they exhibited significantly different catalytic activity in the hydrogenation of MA. Under a lower temperature, the hydrogenation activity of MA to SA linearly increases by increasing the Lewis acid sites surface area when the accessible Ni
0
surface area is enough, whereas it is primarily affected by the Ni
0
sites under high temperature for the hydrogenation of MA to GBL.
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The Effect of Implicit Preferences on Food Consumption: Moderating Role of Ego Depletion and Impulsivity
Ego depletion has been found to moderate the effect of implicit preferences on food consumption, such that implicit preferences predict consumption only under a depleted state. The present study tested how trait impulsivity impacts the effect of implicit preferences on food consumption in a depleted condition. Trait impulsivity was measured by means of self-report and a stop signal task. Results showed that both self-reported impulsivity and behavioral impulsivity moderated the ‘depletion and then eating according to implicit preferences’ effect, albeit in different ways. Participants high in self-reported impulsivity and low in behavioral impulsivity were more vulnerable to the effect of depletion on eating. The implications of these results for extant theories are discussed. Future research is needed to verify whether or not trait impulsivity is associated with vulnerability to depletion across different self-control domains
Learning to Dislike Chocolate: Conditioning Negative Attitudes toward Chocolate and Its Effect on Chocolate Consumption
Evaluative conditioning (EC) procedures can be used to form and change attitudes toward a wide variety of objects. The current study examined the effects of a negative EC procedure on attitudes toward chocolate, and whether it influenced chocolate evaluation and consumption. Participants were randomly assigned to the experimental condition in which chocolate images were paired with negative stimuli, or the control condition in which chocolate images were randomly paired with positive stimuli (50%) and negative stimuli (50%). Explicit and implicit attitudes toward chocolate images were collected. During an ostensible taste test, chocolate evaluation and consumption were assessed. Results revealed that compared to participants in the control condition, participants in the experimental condition showed more negative explicit and implicit attitudes toward chocolate images and evaluated chocolate more negatively during the taste test. However, chocolate consumption did not differ between experimental and control conditions. These findings suggest that pairing chocolate with negative stimuli can influence attitudes toward chocolate, though behavioral effects are absent. Intervention applications of EC provide avenues for future research and practices