The Experts below are selected from a list of 36 Experts worldwide ranked by ideXlab platform
Miao Yan-gang - One of the best experts on this subject based on the ideXlab platform.
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Connections between entropy surface density and Microscopic Property in black holes
2021Co-Authors: Cai Xin-chang, Miao Yan-gangAbstract:We introduce a new Microscopic quantity $\varepsilon $ that describes the contribution of a single black hole molecule to black hole entropy and give a key relation that this Microscopic quantity is proportional to the macroscopic quantity -- entropy surface density $\sigma_{S}$, thus connecting a Microscopic quantity to a macroscopic quantity of black holes. Such a connection provides a new probe for understanding the black hole microstructure from the macroscopic perspective. We also classify black holes in terms of entropy surface density. When its entropy surface density is larger (smaller) than $1/4$, this type of black holes is defined as strong (weak) Bekenstein-Hawking black holes, where the black holes with $1/4$-entropy surface density are regarded as Bekenstein-Hawking black holes. We compute the entropy surface density for four models, where three of them are regular black holes -- the Bardeen black hole, the Ay\'{o}n-Beato-Garc\'{\i}a black hole, and the Hayward black hole, and one of them is a singular black hole -- the five-dimensional neutral Gauss-Bonnet black hole. Under this scheme of classification, the Bardeen black hole, the Ay\'{o}n-Beato-Garc\'{\i}a black hole, and the five-dimensional neutral Gauss-Bonnet black hole belong to the type of strong Bekenstein-Hawking black holes, but the Hayward black hole belongs to the type of weak Bekenstein-Hawking black holes, and the four black holes approach to the Bekenstein-Hawking black hole if their event horizon radii go to infinity. In addition, we find interesting properties in phase transitions from the viewpoint of entropy surface density, or equivalently from the viewpoint of a single black hole molecule entropy, for the five-dimensional neutral Gauss-Bonnet AdS black hole.Comment: v1: 16 pages, 7 figures; v2: clarifications added and typos correcte
Yangang Miao - One of the best experts on this subject based on the ideXlab platform.
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connections between entropy surface density and Microscopic Property in black holes
arXiv: General Relativity and Quantum Cosmology, 2021Co-Authors: Xinchang Cai, Yangang MiaoAbstract:We introduce a new Microscopic quantity $\varepsilon $ that describes the contribution of a single black hole molecule to black hole entropy and give a key relation that this Microscopic quantity is proportional to the macroscopic quantity -- entropy surface density $\sigma_{S}$, thus connecting a Microscopic quantity to a macroscopic quantity of black holes. Such a connection provides a new probe for understanding the black hole microstructure from the macroscopic perspective. We also classify black holes in terms of entropy surface density. When its entropy surface density is larger (smaller) than $1/4$, this type of black holes is defined as strong (weak) Bekenstein-Hawking black holes, where the black holes with $1/4$-entropy surface density are regarded as Bekenstein-Hawking black holes. We compute the entropy surface density for four models, where three of them are regular black holes -- the Bardeen black hole, the Ayon-Beato-Garc\'ia black hole, and the Hayward black hole, and one of them is a singular black hole -- the five-dimensional neutral Gauss-Bonnet black hole. Under this scheme of classification, the Bardeen black hole, the Ayon-Beato-Garc\'ia black hole, and the five-dimensional neutral Gauss-Bonnet black hole belong to the type of strong Bekenstein-Hawking black holes, but the Hayward black hole belongs to the type of weak Bekenstein-Hawking black holes, and the four black holes approach to the Bekenstein-Hawking black hole if their event horizon radii go to infinity. In addition, we find interesting properties in phase transitions from the viewpoint of entropy surface density, or equivalently from the viewpoint of a single black hole molecule entropy, for the five-dimensional neutral Gauss-Bonnet AdS black hole.
Cai Xin-chang - One of the best experts on this subject based on the ideXlab platform.
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Connections between entropy surface density and Microscopic Property in black holes
2021Co-Authors: Cai Xin-chang, Miao Yan-gangAbstract:We introduce a new Microscopic quantity $\varepsilon $ that describes the contribution of a single black hole molecule to black hole entropy and give a key relation that this Microscopic quantity is proportional to the macroscopic quantity -- entropy surface density $\sigma_{S}$, thus connecting a Microscopic quantity to a macroscopic quantity of black holes. Such a connection provides a new probe for understanding the black hole microstructure from the macroscopic perspective. We also classify black holes in terms of entropy surface density. When its entropy surface density is larger (smaller) than $1/4$, this type of black holes is defined as strong (weak) Bekenstein-Hawking black holes, where the black holes with $1/4$-entropy surface density are regarded as Bekenstein-Hawking black holes. We compute the entropy surface density for four models, where three of them are regular black holes -- the Bardeen black hole, the Ay\'{o}n-Beato-Garc\'{\i}a black hole, and the Hayward black hole, and one of them is a singular black hole -- the five-dimensional neutral Gauss-Bonnet black hole. Under this scheme of classification, the Bardeen black hole, the Ay\'{o}n-Beato-Garc\'{\i}a black hole, and the five-dimensional neutral Gauss-Bonnet black hole belong to the type of strong Bekenstein-Hawking black holes, but the Hayward black hole belongs to the type of weak Bekenstein-Hawking black holes, and the four black holes approach to the Bekenstein-Hawking black hole if their event horizon radii go to infinity. In addition, we find interesting properties in phase transitions from the viewpoint of entropy surface density, or equivalently from the viewpoint of a single black hole molecule entropy, for the five-dimensional neutral Gauss-Bonnet AdS black hole.Comment: v1: 16 pages, 7 figures; v2: clarifications added and typos correcte
Xinchang Cai - One of the best experts on this subject based on the ideXlab platform.
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connections between entropy surface density and Microscopic Property in black holes
arXiv: General Relativity and Quantum Cosmology, 2021Co-Authors: Xinchang Cai, Yangang MiaoAbstract:We introduce a new Microscopic quantity $\varepsilon $ that describes the contribution of a single black hole molecule to black hole entropy and give a key relation that this Microscopic quantity is proportional to the macroscopic quantity -- entropy surface density $\sigma_{S}$, thus connecting a Microscopic quantity to a macroscopic quantity of black holes. Such a connection provides a new probe for understanding the black hole microstructure from the macroscopic perspective. We also classify black holes in terms of entropy surface density. When its entropy surface density is larger (smaller) than $1/4$, this type of black holes is defined as strong (weak) Bekenstein-Hawking black holes, where the black holes with $1/4$-entropy surface density are regarded as Bekenstein-Hawking black holes. We compute the entropy surface density for four models, where three of them are regular black holes -- the Bardeen black hole, the Ayon-Beato-Garc\'ia black hole, and the Hayward black hole, and one of them is a singular black hole -- the five-dimensional neutral Gauss-Bonnet black hole. Under this scheme of classification, the Bardeen black hole, the Ayon-Beato-Garc\'ia black hole, and the five-dimensional neutral Gauss-Bonnet black hole belong to the type of strong Bekenstein-Hawking black holes, but the Hayward black hole belongs to the type of weak Bekenstein-Hawking black holes, and the four black holes approach to the Bekenstein-Hawking black hole if their event horizon radii go to infinity. In addition, we find interesting properties in phase transitions from the viewpoint of entropy surface density, or equivalently from the viewpoint of a single black hole molecule entropy, for the five-dimensional neutral Gauss-Bonnet AdS black hole.
Richard J Spontak - One of the best experts on this subject based on the ideXlab platform.
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extended chemical crosslinking of a thermoplastic polyimide macroscopic and Microscopic Property development
Macromolecular Rapid Communications, 2008Co-Authors: Christopher M Aberg, Ali E Ozcam, Jacob M Majikes, Mohamed A Seyam, Richard J SpontakAbstract:Polyimides are well established as gas separation membranes due to their intrinsically low free volume and correspondingly high H 2 selectivity relative to other gases such as CO 2 . Prior studies have established that H 2 /CO 2 selectivity can be improved by crosslinking polyimides with diamines differing in spacer length. In this work, we follow the evolution of macroscopic and Microscopic properties of a commercial polyimide over long crosslinking times (t x ) with 1,3-diaminopropane. According to spectroscopic analysis, the crosslinking reaction saturates after ≈24 h, whereas tensile, nanoindentation and stress relaxation tests reveal that the material stiffens, and possesses a long relaxation time that increases with increasing t x . Although differential scanning calorimetry shows that the glass transition temperature decreases systematically with increasing t x , permeation studies indicate that the permeabilities of H 2 and CO 2 decrease, while the H 2 /CO 2 selectivity increases markedly, with increasing t x . At long t x , the polyimide becomes impermeable to CO 2 , suggesting that it could be used as a barrier material.