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991.
992.
The energy content of the charged-Kerr(CK)spacetime surrounded by dark energy(DE)is investigated using approximate Lie symmetry methods for the differential equations.For this,we consider three different DE scenarios:cosmological constant with an equation of state parameter$ωq=-2/3,quintessence DE with an equation of state parameterωc=-1,and a frustrated network of cosmic strings with an equation of state parameterωn=-1/3.To study the gravitational energy of the CK black hole surrounded by the DE,we explore the symmetries of the 2nd-order perturbed geodesic equations.It is noticed,for all the values ofω,the exact symmetries are recovered as 2nd-order approximate trivial symmetries.These trivial approximate symmetries give the rescaling of arc length parameter s in this spacetime which indicates that the energy in the underlying spacetime has to be rescaled by a factor that depends on the black hole parameters and the DE parameter.This rescaling factor is compared with the factor of the CK spacetime found in[Hussain et al.Gen.Relativ.Gravit.(2009)]and the effects of the DE on it are discussed.It is observed that for all the three values of the equation of state parameterω,the effect of DE results in decreased energy content of the black hole spacetime,regardless of values of the charge Q,spin a and the DE parameterα.This reduction in the energy content due to the involvement of the DE favours the idea of mass reduction of black holes by accretion of DE given by[Babichev et al.Phys.Rev.Lett.(2004)]. 相似文献
993.
A multi-charged particle model with local U(1)μ-τ to explain muon g–2, flavor physics,and possible collider signature 下载免费PDF全文
We consider a model with multi-charged particles, including vector-like fermions, and a charged scalar under a local \begin{document}$ U(1)_{\mu - \tau} $\end{document} ![]()
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symmetry. We search for an allowed parameter region explaining muon anomalous magnetic moment (muon \begin{document}$ g-2 $\end{document} ![]()
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) and \begin{document}$ b \to s \ell^+ \ell^- $\end{document} ![]()
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anomalies, satisfying constraints from the lepton flavor violations, Z boson decays, meson anti-meson mixing, and collider experiments. Via numerical analysis, we explore the typical size of the muon \begin{document}$ g-2 $\end{document} ![]()
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and Wilson coefficients to explain the \begin{document}$ b \to s \ell^+ \ell^- $\end{document} ![]()
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anomalies in our model when all other experimental constraints are satisfied. Subsequently, we discuss the collider physics of the multicharged vectorlike fermions, considering a number of benchmark points in the allowed parameter space. 相似文献
994.
A comprehensive study was performed for the design of ABX3 perovskites, (A = Li, K, Na, B = Ge, Sn, Pb, X = F, Cl, Br, I) and organic hole transfer materials, HTMs (Fu-2a, Fu-2b, Fu-2c, and Dm-Q) for efficient perovskite solar cells (PSCs) through quantum chemistry calculations. Photovoltaic characteristics of the investigated perovskites are strongly affected by the halide anions. The results reveal that reducing the exciton binding energy of perovskites enhances the rate of the formation/dissociation of holes and electrons so F-based perovskites are superior from this viewpoint. Additionally, the electron and hole injection processes are more favorable in the case of the F-based perovskites in comparison with other studied perovskites. Moreover, spectroscopic properties of the perovskites demonstrate that KSnCl3, NaSnCl3, and F-based perovskites exhibit a greater ability of the light-harvesting and incident photon to current conversion efficiency. Ultimately, based on diverse analyses, F-based perovskites, KSnCl3 and NaSnCl3 are the preferred candidates to be applied in the PSCs due to an excellent incident photon to current conversion efficiency, light-harvesting efficiency, short circuit current, and solar cell final efficiency. 相似文献
995.
为了满足社会对高分子材料与工程专业人才的需求,培养学生的实际动手能力,提高学生分析问题,解决问题的水平,结合我院多年来开展《高分子物理实验》的实践经验,对其中的综合性、设计性实验进行了改革。在实验讲义的编写过程中,把教师科研项目成果进行提炼,设计出符合本科教学要求的实验内容,在完成一个综合性、设计性实验的过程中将几个简单的高分子物理实验进行有机串联,同时建立了有效的评价体系。实践结果表明,教学效果显著提高,学生能自觉积极主动地参与实践,达到了预期的目的。 相似文献
996.
997.
Dr. Matthew P. Aldred Chong Li Prof. Ming‐Qiang Zhu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(50):16037-16045
We report the optical properties of tetraphenylethene (TPE) and other TPE derivatives functionalised with an octyl group (TPE‐OCT) and polyethyleneglycol group (TPE‐PEG) in the side chain. We compared TPE‐OCT and TPE‐PEG with TPE in both organic solvents and under aqueous conditions. All materials exhibit aggregation‐induced emission, however, uncommonly, TPE‐PEG seems to aggregate in aqueous solution with enhanced photoluminescence quantum efficiency (PLQE) relative to that in organic solvents. All three materials can be photo‐oxidised in solution to their diphenylphenanthrene derivative by irradiation with UV light (at both ≈1 and ≈5 mW cm?2), with a subsequent enhancement in PL efficiency. The electron‐donating ether group increases the rate of oxidation relative to bare TPE and also photo‐oxidation was shown to be solvent and concentration dependent. Finally, photo‐oxidation was also demonstrated in the aggregate state. 相似文献
998.
999.
We study the thermodynamic phase transition of a quantum-corrected Schwarzschild black hole. The modified metric affects the critical temperature which is slightly less than the conventional one. The space without black holes is not the hot flat space but the hot curved space due to vacuum fluctuations so that there appears a type of Gross–Perry–Yaffe phase transition even for the very small size of black hole, which is impossible for the thermodynamics of the conventional Schwarzschild black hole. We discuss physical consequences of the new phase transition in this framework. 相似文献
1000.
We study the evolution of primordial black holes by considering present universe is no more matter dominated rather vacuum energy dominated. We also consider the accretion of radiation, matter and vacuum energy during respective dominance period. In this scenario, we found that radiation accretion efficiency should be less than 0.366 and accretion rate is much larger than previous analysis by Nayak et al. (2009) [1]. Thus here primordial black holes live longer than previous works Nayak and Singh (2011) [1]. Again matter accretion slightly increases the mass and lifetime of primordial black holes. However, the vacuum energy accretion is slightly complicated one, where accretion is possible only up to a critical time. If a primordial black hole lives beyond critical time, then its? lifespan increases due to vacuum energy accretion. But for presently evaporating primordial black holes, critical time comes much later than their evaporating time and thus vacuum energy could not affect those primordial black holes. 相似文献