23,800 research outputs found
The 3G standard setting strategy and indigenous innovation policy in China is TD-SCDMA a flagship?
In the time of “network economy”, industries and the public have stressed several “battles for dominance” between two or more rival technologies, often involving well-known firms operating in highly visible industries. In this paper, we are going to focus on the Chinese self-developed standard TD-SCDMA to perceive the implication and target of the nation’s policy and strategy. The motivation of the research starts from the interesting fact we observed: TD-SCDMA is named as the Chinese made standard, however the Chinese hold core patent technology is still about 7%, while most of the rest part is still taken by other foreign companies. The “faultage” between the small share reality and a self made standard sweet dream implies a well plotted strategy. In order to understand it, we firstly raise the question of why the Chinese government postpones the 3G decision again and again. Then we go further to probe why the standard-setting of TD-SCDMA has aroused wide attention as a strategic tool to fulfill “indigenous innovation”, and finally becomes part of national science and technology policy to increase international competitiveness? We are going to use economics theories to understand the essence of the creation of TD-SCDMA, and its relation to China’s interests.3G, standard, innovation, China
Energy Spectrum and Phase Transition of Superfluid Fermi Gas of Atoms on Noncommutative Space
Based on the Bogoliubov non-ideal gas model, we discuss the energy spectrum
and phase transition of the superfluid Fermi gas of atoms with a weak
attractive interaction on the canonical noncommutative space. Because the
interaction of a BCS-type superfluid Fermi gas originates from a pair of
Fermionic quasi-particles with opposite momenta and spins, the Hamiltonian of
the Fermi gas on the noncommutative space can be described in terms of the
ordinary creation and annihilation operators related to the commutative space,
while the noncommutative effect appears only in the coefficients of the
interacting Hamiltonian. As a result, we can rigorously solve the energy
spectrum of the Fermi gas on the noncommutative space exactly following the way
adopted on the commutative space without the use of perturbation theory. In
particular, different from the previous results on the noncommutative
degenerate electron gas and superconductor where only the first order
corrections of the ground state energy level and energy gap were derived, we
obtain the nonperturbative energy spectrum for the noncommutative superfluid
Fermi gas, and find that each energy level contains a corrected factor of
cosine function of noncommutative parameters. In addition, our result shows
that the energy gap becomes narrow and the critical temperature of phase
transition from a superfluid state to an ordinary fluid state decreases when
compared with that in the commutative case
Transport Exponents of Sturmian Hamiltonians
We consider discrete Schr\"odinger operators with Sturmian potentials and
study the transport exponents associated with them. Under suitable assumptions
on the frequency, we establish upper and lower bounds for the upper transport
exponents. As an application of these bounds, we identify the large coupling
asymptotics of the upper transport exponents for frequencies of constant type.
We also bound the large coupling asymptotics uniformly from above for
Lebesgue-typical frequency. A particular consequence of these results is that
for most frequencies of constant type, transport is faster than for Lebesgue
almost every frequency. We also show quasi-ballistic transport for all coupling
constants, generic frequencies, and suitable phases.Comment: 30 page
Analysis of the scalar, axialvector, vector, tensor doubly charmed tetraquark states with QCD sum rules
In this article, we construct the axialvector-diquark-axialvector-antidiquark
type currents to interpolate the scalar, axialvector, vector, tensor doubly
charmed tetraquark states, and study them with QCD sum rules systematically by
carrying out the operator product expansion up to the vacuum condensates of
dimension 10 in a consistent way, the predicted masses can be confronted to the
experimental data in the future. We can search for those doubly charmed
tetraquark states in the Okubo-Zweig-Iizuka super-allowed strong decays to the
charmed meson pairs.Comment: 23 pages, 29 figures. arXiv admin note: substantial text overlap with
arXiv:1708.0454
Energy spread and current-current correlation in quantum systems
We consider energy (heat) transport in quantum systems, and establish a
relationship between energy spread and energy current-current correlation
function. The energy current-current correlation is related to thermal
conductivity by the Green-Kubo formula, and thus this relationship allows us to
study conductivity directly from the energy spread process. As an example, we
investigate a spinless fermion model; the numerical results confirm the
relationship.Comment: 5 pages, 2 figure
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