1,846 research outputs found
Chinese and North American Culture: a New Perspective in Linguistics Studies
We explored the two cultures in the two countries. There has been discussed on Chinese culture and North American culture. Chinese language, ceramics, architecture, music, dance, literature, martial arts, cuisine, visual arts, philosophy, business etiquette, religion, politics, and history have global influence, while its traditions and festivals are also celebrated, instilled, and practiced by people around the world. The culture of North America refers to the arts and other manifestations of human activities and achievements from the continent of North America. The American way of life or simply the American way is the unique lifestyle of the people of the United States of America. It refers to a nationalist ethos that adheres to the principle of life, liberty and the pursuit of happiness
Quantum Limits of Interferometer Topologies for Gravitational Radiation Detection
In order to expand the astrophysical reach of gravitational wave detectors,
several interferometer topologies have been proposed to evade the thermodynamic
and quantum mechanical limits in future detectors. In this work, we make a
systematic comparison among them by considering their sensitivities and
complexities. We numerically optimize their sensitivities by introducing a cost
function that tries to maximize the broadband improvement over the sensitivity
of current detectors. We find that frequency-dependent squeezed-light injection
with a hundred-meter scale filter cavity yields a good broadband sensitivity,
with low complexity, and good robustness against optical loss. This study gives
us a guideline for the near-term experimental research programs in enhancing
the performance of future gravitational-wave detectors.Comment: grammar correcte
Variational system identification of the partial differential equations governing microstructure evolution in materials: Inference over sparse and spatially unrelated data
Pattern formation is a widely observed phenomenon in diverse fields including
materials physics, developmental biology and ecology, among many others. The
physics underlying the patterns is specific to the mechanisms, and is encoded
by partial differential equations (PDEs). With the aim of discovering hidden
physics, we have previously presented a variational approach to identifying
such systems of PDEs in the face of noisy data at varying fidelities (Computer
Methods in Applied Mechanics and Engineering, 353:201-216, 2019). Here, we
extend our variational system identification methods to address the challenges
presented by image data on microstructures in materials physics. PDEs are
formally posed as initial and boundary value problems over combinations of time
intervals and spatial domains whose evolution is either fixed or can be
tracked. However, the vast majority of microscopy techniques for evolving
microstructure in a given material system deliver micrographs of pattern
evolution over domains that bear no relation with each other at different time
instants. The temporal resolution can rarely capture the fastest time scales
that dominate the early dynamics, and noise abounds. Furthermore, data for
evolution of the same phenomenon in a material system may well be obtained from
different physical specimens. Against this backdrop of spatially unrelated,
sparse and multi-source data, we exploit the variational framework to make
judicious choices of weighting functions and identify PDE operators from the
dynamics. A consistency condition arises for parsimonious inference of a
minimal set of the spatial operators at steady state. It is complemented by a
confirmation test that provides a sharp condition for acceptance of the
inferred operators. The entire framework is demonstrated on synthetic data that
reflect the characteristics of the experimental material microscopy images
Game theory-based resource allocation for secure WPCN multiantenna multicasting systems
This paper investigates a secure wireless-powered multiantenna multicasting system, where multiple power beacons (PBs) supply power to a transmitter in order to establish a reliable communication link with multiple legitimate users in the presence of multiple eavesdroppers. The transmitter has to harvest radio frequency (RF) energy from multiple PBs due to the shortage of embedded power supply before establishing its secure com- munication. We exploit a novel and practical scenario that the PBs and the transmitter may belong to different operators and a hierarchical energy interaction between the PBs and the transmitter is considered. Specifically, the monetary incentives are required for the PBs to assist the transmitter for secure communications. This leads to the formulation of a Stackelberg game for the secure wireless-powered multiantenna multicasting system, where the transmitter and the PB are modelled as leader and follower, respectively, each maximizing their own utility function. The closed-form Stackelberg equilibrium of the formulated game is then derived where we study various scenarios of eavesdroppers and legitimate users that can have impact on the optimality of the derived solutions. Finally, numerical results are provided to validate our proposed schemes
Towards the Laboratory Search for Space-Time Dissipation
It has been speculated that gravity could be an emergent phenomenon, with
classical general relativity as an effective, macroscopic theory, valid only
for classical systems at large temporal and spatial scales. As in classical
continuum dynamics, the existence of underlying microscopic degrees of freedom
may lead to macroscopic dissipative behaviors. With the hope that such
dissipative behaviors of gravity could be revealed by carefully designed
experiments in the laboratory, we consider a phenomenological model that adds
dissipations to the gravitational field, much similar to frictions in solids
and fluids. Constraints to such dissipative behavior can already be imposed by
astrophysical observations and existing experiments, but mostly in lower
frequencies. We propose a series of experiments working in higher frequency
regimes, which may potentially put more stringent bounds on these models.Comment: 18 pages, 8 figure
Quantum phase transitions in a two-dimensional quantum XYX model: Ground-state fidelity and entanglement
A systematic analysis is performed for quantum phase transitions in a
two-dimensional anisotropic spin 1/2 anti-ferromagnetic XYX model in an
external magnetic field. With the help of an innovative tensor network
algorithm, we compute the fidelity per lattice site to demonstrate that the
field-induced quantum phase transition is unambiguously characterized by a
pinch point on the fidelity surface, marking a continuous phase transition. We
also compute an entanglement estimator, defined as a ratio between the
one-tangle and the sum of squared concurrences, to identify both the
factorizing field and the critical point, resulting in a quantitative agreement
with quantum Monte Carlo simulation. In addition, the local order parameter is
"derived" from the tensor network representation of the system's ground state
wave functions.Comment: 4+ pages, 3 figure
Fidelity and quantum phase transitions
It is shown that the fidelity, a basic notion of quantum information science,
may be used to characterize quantum phase transitions, regardless of what type
of internal order is present in quantum many-body states. If the fidelity of
two given states vanishes, then there are two cases: (1) they are in the same
phase if the distinguishability results from irrelevant local information; or
(2) they are in different phases if the distinguishability results from
relevant long-distance information. The different effects of irrelevant and
relevant information are quantified, which allows us to identify unstable and
stable fixed points (in the sense of renormalization group theory). A physical
implication of our results is the occurrence of the orthogonality catastrophe
near the transition points.Comment: 5 pages, 2 figure
Detection of hepatocellular carcinoma with multi-slice spiral CT by using double-arterial phase and portal venous phase enhanced scanning: Effect of iodine concentration of contrast material
The purpose of the study is to evaluate the effect of iodine concentration of contrast material on detection of hepatocellular carcinoma with multi-slice spiral computed tomography (CT) by using double-arterial phase and portal venous phase enhanced scanning. Ninety-four (94) patients with hepatocellular carcinoma (HCC) were examined by hepatic plain CT and contrast-enhanced CT including early arterial phase (EAP), late arterial phase (LAP) and portal venous phase (PVP) scanning. Patientswere randomized into two groups to receive Iopamidol 370 mg /ml (47 patients) and 300 mg /ml (47 patients). The images were interpreted by two experienced radiologists together prospectively. The detection sensitivity for tumors of two size categories (2 or >2 cm) and iodine concentration groups were calculated and analyzed. A total of 318 lesions were detected with 86 2 cm in size and 232 >2 cm. For EAP and LAP, the sensitivity of Iopamidol 370 mg I/ml group was significantly higher than Iopamidol 300 mg I/ml group for tumors 2 cm and all tumors. For PVP, there were no significant differences between groups. We concluded that high-iodine-concentration contrast material could improve the detection of HCC for EAP and LAP, especially for tumor 2 cm
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