13,813 research outputs found
Quark Condensates in Nuclear Matter in the Global Color Symmetry Model of QCD
With the global color symmetry model being extended to finite chemical
potential, we study the density dependence of the local and nonlocal scalar
quark condensates in nuclear matter. The calculated results indicate that the
quark condensates increase smoothly with the increasing of nuclear matter
density before the critical value (about 12) is reached. It also
manifests that the chiral symmetry is restored suddenly as the density of
nuclear matter reaches its critical value. Meanwhile, the nonlocal quark
condensate in nuclear matter changes nonmonotonously against the space-time
distance among the quarks.Comment: 15 pages, 3 figure
Reevaluation of the density dependence of nucleon radius and mass in the global color symmetry model of QCD
With the global color symmetry model (GCM) at finite chemical potential, the
density dependence of the bag constant, the total energy and the radius of a
nucleon in nuclear matter is investigated. A relation between the nuclear
matter density and the chemical potential with the action of QCD being taken
into account is obtained. A maximal nuclear matter density for the existence of
the bag with three quarks confined within is given. The calculated results
indicate that, before the maximal density is reached, the bag constant and the
total energy of a nucleon decrease, and the radius of a nucleon increases
slowly, with the increasing of the nuclear matter density. As the maximal
nuclear matter density is reached, the mass of the nucleon vanishes and the
radius becomes infinite suddenly. It manifests that a phase transition from
nucleons to quarks takes place.Comment: 18 pages, 3 figure
Building environment assessment methods and social studies of rural villages in Yunnan and urban development in Chongqing City, Southwest China
Recent urbanization processes and corresponding government policies in China have highlighted the need for much greater understanding of sustainable development and the requirements for sustainability in settings that are very different in rural and urban regions. This paper examines practice and knowledge linked to typical vernacular houses constructed since 1950 in Yunnan Province and regional buildings in Chongqing City in Southwest China. Both areas have played crucial roles in contributing to regional architectural design since the beginning of the 20th Century because of the diversity arising from numerous ethnic groups and various climate types and topography features in the region. The study explores how academic and end-user knowledge accumulated and developed, and how this has revealed social, cultural and political influences on how designers and consumers were motivated towards sustainable design over the same time period. It is argued that locally shared knowledge bases should be considered important for informing governmental policies, planning strategy and consumers’ preferences, as well as influencing actions and social acceptance in relation to sustainable development. Furthermore, sustainable design should not be regarded as a contemporary new idea, but one that has its roots in the historical changes in built environment design and practice
1-(2-Ureidoethyl)quinolinium tetraphenylborate
In the cation of the title salt, C12H14N3O+·C24H20B−, the dihedral angle between the quinoline ring and the mean plane of the urea fragment is 61.51 (5)°. In the crystal, the cations interact through weak C—H⋯O hydrogen bonding, forming a zigzag chain along the c-axis direction; the cations and anions are involved in weak intermolecular C—H⋯π and N—H⋯π interactions as donors and acceptors, respectively
The Schrodinger-like Equation for a Nonrelativistic Electron in a Photon Field of Arbitrary Intensity
The ordinary Schrodinger equation with minimal coupling for a nonrelativistic
electron interacting with a single-mode photon field is not satisfied by the
nonrelativistic limit of the exact solutions to the corresponding Dirac
equation. A Schrodinger-like equation valid for arbitrary photon intensity is
derived from the Dirac equation without the weak-field assumption. The
"eigenvalue" in the new equation is an operator in a Cartan subalgebra. An
approximation consistent with the nonrelativistic energy level derived from its
relativistic value replaces the "eigenvalue" operator by an ordinary number,
recovering the ordinary Schrodinger eigenvalue equation used in the formal
scattering formalism. The Schrodinger-like equation for the multimode case is
also presented.Comment: Tex file, 13 pages, no figur
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