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Search Results: 1 - 10 of 47844 matches for " Qiu He Peng "
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The physics of strong magnetic fields and activity of magnetars
Qiu He Peng,Hao Tong
Physics , 2009,
Abstract: A phase transition from paramagnetism to ferromagnetism in neutron star interior is explored. Since there is $^3$P$_2$ neutron superfluid in neutron star interior, it can be treated as a system of magnetic dipoles. Under the presence of background magnetic field, the magnetic dipoles tend to align in the same direction. Below a critical temperature, there is a phase transition from paramagnetism to ferromagnetism. And this gives a convenient explanation of the strong magnetic field of magnetars. In our point of view, there is an upper limit for the magnetic field strength of magnetars. The maximum field strength of magnetars is about $(3.0-4.0)\times 10^{15}$ G. This can be tested directly by further investigations. Magnetars are instable due to the ultra high Fermi energy of electrons. The Landau column becomes a very long cylinder along the magnetic field, but it is very narrow and the Fermi energy of electron gas is given as $E_F(e)\approx40(B/B_{cr})^{1/4}$ when $B\gg B_{cr}$. $E_F(e)\approx90MeV$ When $B\sim10^{15}$ G. Hence, the electron capture process $e^-+p\to n+\nu_e$ will be happen rapidly. Thus the $^3$P$_2$ Cooper pairs will be destroyed quickly by the outgoing neutrons with high energy. It will cause the isotropic superfluid disappear and then the magnetic field induced by the $^3$P$_2$ Cooper pairs will be also disappear. These energy will immediately be transmitted into thermal energy and then transformed into the radiation energy with X-ray - soft $\gamma$-ray. We may get a conclusion that the activity of magnetars originates from instability caused by the high Fermi energy of electrons in extra strong magnetic field.
Qiu He,Kang An,Peng Wang,Peng Yu
Acta Crystallographica Section E , 2010, DOI: 10.1107/s160053681002221x
Abstract: The title compound, C16H12FN3OS, was synthesized by the reaction of 5-(4-methoxyphenyl)-1,3,4-thiadiazol-2-amine and 4-fluorobenzaldehyde. An intramolecular C—H...S hydrogen bond results in the formation of two five-membered rings. In the crystal structure, intermolecular C—H...N hydrogen bonding links the molecules, forming a two-dimensional network.
Peng Yu,Peng Wang,Jian-Qiang Zhang,Qiu He
Acta Crystallographica Section E , 2011, DOI: 10.1107/s1600536811008841
Abstract: The title compound, C16H12ClN3S, was synthesized by the reaction of 5-(4-methylphenyl)-1,3,4-thiadiazol-2-amine and 4-chlorobenzaldehyde. The thiadiazole ring is essentially planar with mean deviation of 0.0042 .
Peng Wang,Rong Wan,Peng Yu,Qiu He
Acta Crystallographica Section E , 2010, DOI: 10.1107/s1600536810036950
Abstract: The title compound, C5H6ClN3, was synthesized by the reaction of 2,3-dichloropyridine and hydrazine hydrate. An intramolecular N—H...Cl hydrogen bond results in the formation of a planar (mean deviation 0.038 ) five-membered ring. In the crystal, intermolecular N—H...N hydrogen bonds link the molecules into a three-dimensional network.
Peng Yu,Kang An,Qiu He,Jian-Qaing Zhang
Acta Crystallographica Section E , 2010, DOI: 10.1107/s1600536810023354
Abstract: In the title compound, C17H11FN4O3S2, the five-membered thiazolidinone and thiadiazole rings are almost planar, with r.m.s. deviations of 0.017 and 0.0019 , respectively. The 4-fluorophenyl ring is almost perpendicular to the thiadiazole ring, making a dihedral angle of 89.5 (3)°. The 4-nitrophenyl ring is nearly coplanar with the thiadiazole ring, the dihedral angle being 7.9 (3)°. The crystal structure is stabilized by two intermolecular C—H...O hydrogen bonds.
Verifying Non-Abelian Statistics by Numerical Braiding Majorana Fermions
Qiu-Bo Cheng,Jing He,Su-Peng Kou
Physics , 2014,
Abstract: Recently, Majorana fermions (MFs) have attracted intensive attention because of their possible non-Abelian statistics. This paper points out an approach to verify the non-Abelian statistics of MFs in topological superconductors. We introduce a single particle representation of braiding operators that obey anti-commutating relation of Bogolubov-de Gennes (BdG) states. From the relationship between the braiding operator of MFs and that of BdG states, we verify non-Abelian statistics of MFs in 1D and 2D topological SCs.
The relationship of electron Fermi energy with strong magnetic fields
Qiu He Peng,Zhi Fu Gao,Na Wang
Physics , 2012, DOI: 10.1063/1.4763455
Abstract: In order to depict the quantization of Landau levels, we introduce Dirac $\delta$ function, and gain a concise expression for the electron Fermi energy, $E_{F}(e) \propto B^{1/4}$. The high soft X-ray luminosities of magnetars may be naturally explained by our theory.
Classification of Majorana Fermions in Two-Dimensional Topological Superconductors
Qiu-Bo Cheng,Jing He,Su-Peng Kou
Physics , 2015,
Abstract: Recently, Majorana Fermions (MFs) have attracted intensive attention due to their exotic statistics and possible applications in topological quantum computation (TQC). They are proposed to exist in various two-dimensional (2D) topological systems, such as px+ipy topological superconductor and nanowire-superconducting hybridization system. In this paper, two types of Majorana Fermions with different polygon sign rules are pointed out. A "smoking gun" numerical evidence to identify MF's classification is presented through looking for the signature of a first order topological quantum phase transition. By using it, several 2D topological superconductors are studied.
Structural basis of interaction between protein tyrosine phosphatase PCP-2 and β-catenin
Yaqin He,Hexin Yan,Hui Dong,Peng Zhang,Liang Tang,Xiuhua Qiu,Mengchao Wu,Hongyang Wang
Science China Life Sciences , 2005, DOI: 10.1007/BF02879669
Abstract: PCP-2 is a member of receptor-like protein tyrosine phosphatase of the MAM domain family. To investigate which part of PCP-2 was involved in its interaction with β-catenin, we constructed various deletion mutants of PCP-2. These PCP-2 mutants and wild-type PCP-2 were co-transfected into BHK-21 cells with β-catenin individually. Anin vivo binding assay revealed that the expression of wild-type PCP-2, PCP-2 ΔC1C2 (deleted PCP-2 without both PTP domains) and PCP-2 ΔC2 (deleted PCP-2 without the second PTP domain) could be immunoprecipitated by anti-catenin antibody in every co-transfection, but PCP-2 EXT (deleted PCP-2 without the juxtamembrane region and both PTP domains) was missing, which implied that PCP-2 and β-catenin could associate directly and the juxtamembrane region in PCP-2 was sufficient for the process.
Qing-Peng He,Xiao-Qiang Qin,Xiao Wang,Qiu-Lan Shi
Acta Crystallographica Section E , 2008, DOI: 10.1107/s1600536808023866
Abstract: The asymmetric unit of the title compound, C25H25NO2, contains two independent molecules. The crystal packing exhibits weak intermolecular C—H...O, C—H...π and π–π interactions.
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