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"Guo, Di"
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Thick branes with inner structure in mimetic f(R) gravity
In this paper, we study the structure and gravitational resonances of thick branes generated by a mimetic scalar field in f(R) gravity. We obtain several typical thick brane solutions for f(R)=R+αR2. To study their stability, we analyze the tensor perturbation of the metric. It is shown that any thick brane model with df/dR>0 is stable and the graviton zero mode can be localized on the brane for each solution, which indicates that the four-dimensional Newtonian gravity can be restored. The effect of the parameter α on the gravitational resonances is studied. As a brane splits into multi sub-branes, the effective potential of the tensor perturbation will have an abundant inner structure with multi-wells, and this will lead to new phenomena of the gravitational resonances.
Journal Article
Jie neng jian zhu = Sustainable & green building
Ben shu jiang shu le jie neng jian zhu zai ban gong shang ye jie de ti xian he yun yong, Bing li ju ma de li ke kou ke le gong si zong bu, Ha xi xin qu fa zhan da sha, Rui shi lian bang shui zi yuan yan jiu zhong xin ban gong da lou, Du lin qu di fang fa yuan deng jian zhu shi li jin xing fen xi.
BOOK
The effect of scalar hair on the charged black hole with the images from accretions disk
In this paper, we investigate the optical properties of a charged black hole with scalar hair (CSH) within the context of four-dimensional Einstein–Maxwell–Dilaton gravity. To achieve this, we consider three distinct toy models of thin accretion disks. The presence of dilaton coupling allows us to express both the solutions of CSH and the Reissner–Nordström (RN) black hole in terms of their mass (
M
) and charge (
Q
). Our findings reveal differences in the effective potentials
V
eff
, photon sphere radii
r
ph
, and innermost stable circular orbit
r
isco
between the CSH and RN black hole cases, which become increasingly pronounced as the charge parameter
Q
increases. However, no noticeable distinctions are observed concerning the critical impact parameter
b
ph
. When the ratio of the photon ring band and the lensed ring band exceeds 0.1, it may suggest the presence of a charged black hole with scalar hair. Furthermore, our results underscore the significant influence of the charge parameter
Q
on the brightness distributions of the direct, lensed ring, and photon ring for three standard emission functions. These findings emphasize the potential for distinguishing between CSH and RN black holes through an analysis of direct intensity and peak brightness in specific accretion disk models.
Journal Article
Shadow of a charged black hole with scalar hair
Seeking singularity free solutions are important for further understanding black holes in quantum level. Recently, a five-dimensional singularity free black hole/topological star was constructed (Bah and Heidmann in Phys Rev Lett 126:151101, 2021). Through the Kaluza–Klein reduction, an effective four-dimensional static spherically symmetric charged black hole with scalar hair can be obtained. In this paper, we study shadow of this charged black hole with scalar hair in terms of four kinds of observers, i.e., static observers, surrounding observers, freely falling observers, and escaping observers in four-dimensional spacetime. For a spherically symmetric black hole, the shadow is circular for any observer, but the shadow size depends on the motion status of the observer. On the other hand, the effect of plasma is also investigated by a simple model. The radius of the photon sphere depends on the plasma model. Most importantly, we find that the shadow sizes do not monotonically decrease with
r
in some cases.
Journal Article
بيان الدورة العامة الحادية عشرة للجنة المركزية المنبثقة عن المؤتمر الوطني الثامن للحزب الشيوعي الصيني : (أقر في 12 أغسطس-آب-عام 1966)
عقدت الدورة العامة الحادية عشرة للجنة المركزية المنبثقة عن المؤتمر الوطني الثامن للحزب الشيوعي الصيني في بكين من 1 الى 12 أغسطس (آب) عام 1966، وقد ترأس الدورة العامة الحادية عشرة الرفيق ماو تسي تونغ، وحضرها أعضاء اللجنة المركزية وأعضاؤها المرشحون : وحضرها كذلك الرفاق من مختلف المكاتب الاقليمية للجنة المركزية ومن لجان الحزب في المقاطعات والبلديات والمناطق ذات الحكم الذاتي وأعضاء فرقة الثورة الثقافية للجنة المركزية والرفاق في الدوائر المعنية للجنة المركزية وممثلو المدرسين والطلاب الثوريين في الجامعات والمعاهد العليا بالعاصمة . وقد أقرت الدورة العامة الحادية عشرة بعد المناقشة « قرار اللجنة المركزية للحزب الشيوعي الصيني حول الثورة الثقافية البروليتارية الكبرى » . كما صادقت الدورة العامة بعد النقاش على القرارات السياسية المهمة والاجراءات المهمة فيما يختص بالمسائل الداخلية والخارجية التي أجازها المكتب السياسي للجنة المركزية منذ الدورة العامة العاشرة للجنة المركزية المنبثقة عن المؤتمر الوطني الثامن التي عقدت في سبتمبر (أيلول) عام 1962.
Book
Quasibound and quasinormal modes of a thick brane in Rastall gravity
A
bstract
In this work, we study the gravitational quasinormal modes of the thick brane in Rastall gravity. Using the asymptotic iteration and direct integration methods, we solve the quasinormal frequencies of the Rastall thick brane. We also obtained the waveforms of these quasinormal modes through numerical evolution. The results indicate that although the Rastall thick brane lacks a bound zero mode, when the Rastall parameter
λ
≳ 0, a long-lived quasinormal mode appears. This long-lived quasinormal mode may restore the four-dimensional effective Newtonian potential on the brane on a large scale. This may provide a new perspective for the localization of gravity on thick branes, that a thick brane does not necessarily require the gravity to be localized, perhaps quasi-localized is sufficient.
Journal Article
Charged spherically symmetric and slowly rotating charged black hole solutions in bumblebee gravity
In this paper, we study the scenario in which the matter field is an electromagnetic field nonminimally coupled to the bumblebee vector field. We present exact charged spherically symmetric black hole solutions and slowly rotating charged solutions in bumblebee gravity with and without a cosmological constant. The static spherically symmetric solutions describe the Reissner–Nordström-like black hole and Reissner–Nordström-(anti) de Sitter-like black hole, while the stationary and axially symmetric solutions describe the Kerr–Newman-like black hole and Kerr–Newman–(anti) de Sitter-like black hole. We utilize the Hamilton–Jacobi formalism to study the shadows of the black holes. Additionally, we investigate the effect of the electric charge and Lorentz-violating parameters on the radius of the shadow reference circle and the distortion parameter. We find that the radius of the reference circle decreases with the Lorentz-violating parameter and the charge parameter, while the distortion parameter increases with the Lorentz-violating parameter and the charge parameter.
Journal Article
Light-induced primary amines and o-nitrobenzyl alcohols cyclization as a versatile photoclick reaction for modular conjugation
The advent of click chemistry has had a profound impact on many fields and fueled a need for reliable reactions to expand the click chemistry toolkit. However, developing new systems to fulfill the click chemistry criteria remains highly desirable yet challenging. Here, we report the development of light-induced primary amines and o-nitrobenzyl alcohols cyclization (PANAC) as a photoclick reaction via primary amines as direct click handle, to rapid and modular functionalization of diverse small molecules and native biomolecules. With intrinsic advantages of temporal control, good biocompatibility, reliable chemoselectivity, excellent efficiency, readily accessible reactants, operational simplicity and mild conditions, the PANAC photoclick is robust for direct diversification of pharmaceuticals and biorelevant molecules, lysine-specific modifications of unprotected peptides and native proteins in vitro, temporal profiling of endogenous kinases and organelle-targeted labeling in living systems. This strategy provides a versatile platform for organic synthesis, bioconjugation, medicinal chemistry, chemical biology and materials science.
Developing new click chemistry reactions for robust molecular assembly remains challenging. Here the authors report a light-induced primary amines and
o
-nitrobenzyl alcohols photoclick cyclization for rapid and modular functionalization of small molecules and native biomolecules, in vitro and in living systems.
Journal Article