2,838 research outputs found
Multi-Cell Interference Exploitation: Enhancing the Power Efficiency in Cell Coordination
In this paper, we propose a series of novel coordination schemes for multi-cell downlink communication. Starting
from full base station (BS) coordination, we first propose a
fully-coordinated scheme to exploit beneficial effects of both
inter-cell and intra-cell interference, based on sharing both
channel state information (CSI) and data among the BSs. To
reduce the coordination overhead, we then propose a partiallycoordinated scheme where only intra-cell interference is designed
to be constructive while inter-cell is jointly suppressed by the
coordinated BSs. Accordingly, the coordination only involves
CSI exchange and the need for sharing data is eliminated.
To further reduce the coordination overhead, a third scheme
is proposed, which only requires the knowledge of statistical
inter-cell channels, at the cost of a slight increase on the
transmission power. For all the proposed schemes, imperfect
CSI is considered. We minimize the total transmission power in
terms of probabilistic and deterministic optimizations. Explicitly,
the former statistically satisfies the users’ signal-to-interferenceplus-noise ratio (SINR) while the latter guarantees the SINR
requirements in the worst case CSI uncertainties. Simulation
verifies that our schemes consume much lower power compared
to the existing benchmarks, i.e., coordinated multi-point (CoMP)
and coordinated-beamforming (CBF) systems, opening a new
dimension on multi-cell coordination
The superheated Melting of Grain Boundary
Based on a model of the melting of Grain Boundary (GB), we discuss the
possibility of the existence of superheated GB state. A Molecular Dynamics
simulation presented here shows that the superheated GB state can realized in
the high symmetric tilt GB. Whether the sizes of liquid nuclei exceed a
critical size determined the superheating grain boundary melting or not. Our
results also indicate that the increase of melting point due to pressure is
smaller than the superheating due to nucleation mechanism.Comment: Accepted by PRB, 7 pages and 5 figure
Sensitivity of various body indices and visceral adiposity index in predicting metabolic syndrome among Chinese patients with adult growth hormone deficiency
Global quark polarization in non-central collisions
Partons produced in the early stage of non-central heavy-ion collisions can
develop a longitudinal fluid shear because of unequal local number densities of
participant target and projectile nucleons. Under such fluid shear, local
parton pairs with non-vanishing impact parameter have finite local relative
orbital angular momentum along the direction opposite to the reaction plane.
Such finite relative orbital angular momentum among locally interacting quark
pairs can lead to global quark polarization along the same direction due to
spin-orbital coupling. Local longitudinal fluid shear is estimated within both
Landau fireball and Bjorken scaling model of initial parton production. Quark
polarization through quark-quark scatterings with the exchange of a thermal
gluon is calculated beyond small-angle scattering approximation in a
quark-gluon plasma. The polarization is shown to have a non-monotonic
dependence on the local relative orbital angular momentum dictated by the
interplay between electric and magnetic interaction. It peaks at a value of
relative orbital angular momentum which scales with the magnetic mass of the
exchanged gluons. With the estimated small longitudinal fluid shear in
semi-peripheral collisions at the RHIC energy, the final quark
polarization is found to be small in the weak coupling limit.
Possible behavior of the quark polarization in the strong coupling limit and
implications on the experimental detection of such global quark polarization at
RHIC and LHC are also discussed.Comment: 28 pages,11 figure
The Application of the Multiple Points of a Mold Function of UG MoldWizard in the Design of Cutting Compressor
In recent years, mold industry develops rapidly. The design and manufacture of mold have become an important symbol to measure the level of a country#39s manufacturing industry. Difficult point in the design of the cutting compressor for recycling plastic bottles lies in cutting and compressing plastic bottles at the same time. Use UG MoldWizard to design the working process of injection mold. Design and manufacture the U-lower plastic mold with the aid of a computer. Make optimal design plan of the U-lower plastic in the cutting compressor
Confidence and Backaction in the Quantum Filter Equation
We study the confidence and backaction of state reconstruction based on a
continuous weak measurement and the quantum filter equation. As a physical
example we use the traditional model of a double quantum dot being continuously
monitored by a quantum point contact. We examine the confidence of the estimate
of a state constructed from the measurement record, and the effect of
backaction of that measurement on that state. Finally, in the case of general
measurements we show that using the relative entropy as a measure of confidence
allows us to define the lower bound on the confidence as a type of quantum
discord.Comment: 9 pages, 6 figure
Unusually stronger quantum fluctuation with larger spins: Novel phenomena revealed by emergent magnetism in pressurized high-temperature superconductor FeSe
A counter-intuitive enhancement of quantum fluctuation with larger spins,
together with a few novel physical phenomena, is discovered in studying the
recently observed emergent magnetism in high-temperature superconductor FeSe
under pressure. Starting with experimental crystalline structure from our
high-pressure X-ray refinement, we analyze theoretically the stability of the
magnetically ordered state with a realistic spin-fermion model. We find
surprisingly that in comparison with the magnetically ordered Fe-pnictides, the
larger spins in FeSe suffer even stronger long-range quantum fluctuation that
diminishes their ordering at ambient pressure. This "fail-to-order" quantum
spin liquid state then develops into an ordered state above 1GPa due to
weakened fluctuation accompanying the reduction of anion height and carrier
density. The ordering further benefits from the ferro-orbital order and shows
the observed enhancement around 1GPa. We further clarify the controversial
nature of magnetism and its interplay with nematicity in FeSe in the same
unified picture for all Fe-based superconductors. In addition, the versatile
itinerant carriers produce interesting correlated metal behavior in a large
region of phase space. Our study establishes a generic exceptional paradigm of
stronger quantum fluctuation with larger spins that complements the standard
knowledge of insulating magnetism.Comment: 7 pages, 4 figure
- …