14,616 research outputs found
Isolating the chiral magnetic effect from backgrounds by pair invariant mass
Topological gluon configurations in quantum chromodynamics induce quark
chirality imbalance in local domains, which can result in the chiral magnetic
effect (CME)--an electric charge separation along a strong magnetic field.
Experimental searches for the CME in relativistic heavy ion collisions via the
charge-dependent azimuthal correlator () suffer from large
backgrounds arising from particle correlations (e.g. due to resonance decays)
coupled with the elliptic anisotropy. We propose differential measurements of
the as a function of the pair invariant mass (), by
restricting to high thus relatively background free, and by
studying the dependence to separate the possible CME signal from
backgrounds. We demonstrate by model studies the feasibility and effectiveness
of such measurements for the CME search.Comment: 16 preprint pages 5 figures. v2: added a test with a broad
"instanton/sphaleron" peak, and added clarifying texts; v3: added event-shape
engineering (and two new figures) and expanded discussions on the low
invariant mass region; v4: repeated cautionary discussions in introduction
and conclusion sections, published versio
Conceptual development of a novel photovoltaic-thermoelectric system and preliminary economic analysis
© 2016 Elsevier Ltd Photovoltaic-thermoelectric (PV-TE) hybrid system is one typical electrical production based on the solar wide-band spectral absorption. However the PV-TE system appears to be economically unfeasible owing to the significantly higher cost and lower power output. In order to overcome this disadvantage, a novel PV-TE system based on the flat plate micro-channel heat pipe was proposed in this paper. The mathematic model was built and the performance under different ambient conditions was analyzed. In addition, the annual performance and the preliminary economic analysis of the new PV-TE system was also made to compare to the conventional PV system. The results showed that the new PV-TE has a higher electrical output and economic performance
Segmentation of ultrasound images of thyroid nodule for assisting fine needle aspiration cytology
The incidence of thyroid nodule is very high and generally increases with the
age. Thyroid nodule may presage the emergence of thyroid cancer. The thyroid
nodule can be completely cured if detected early. Fine needle aspiration
cytology is a recognized early diagnosis method of thyroid nodule. There are
still some limitations in the fine needle aspiration cytology, and the
ultrasound diagnosis of thyroid nodule has become the first choice for
auxiliary examination of thyroid nodular disease. If we could combine medical
imaging technology and fine needle aspiration cytology, the diagnostic rate of
thyroid nodule would be improved significantly. The properties of ultrasound
will degrade the image quality, which makes it difficult to recognize the edges
for physicians. Image segmentation technique based on graph theory has become a
research hotspot at present. Normalized cut (Ncut) is a representative one,
which is suitable for segmentation of feature parts of medical image. However,
how to solve the normalized cut has become a problem, which needs large memory
capacity and heavy calculation of weight matrix. It always generates over
segmentation or less segmentation which leads to inaccurate in the
segmentation. The speckle noise in B ultrasound image of thyroid tumor makes
the quality of the image deteriorate. In the light of this characteristic, we
combine the anisotropic diffusion model with the normalized cut in this paper.
After the enhancement of anisotropic diffusion model, it removes the noise in
the B ultrasound image while preserves the important edges and local details.
This reduces the amount of computation in constructing the weight matrix of the
improved normalized cut and improves the accuracy of the final segmentation
results. The feasibility of the method is proved by the experimental results.Comment: 15pages,13figure
Spin-orbit and orbit-orbit strengths for radioactive neutron-rich doubly magic nucleus Sn in relativistic mean field theory
Relativistic mean field (RMF) theory is applied to investigate the properties
of the radioactive neutron-rich doubly magic nucleus Sn and the
corresponding isotopes and isotones. The two-neutron and two-proton separation
energies are well reproduced by the RMF theory. In particular, the RMF results
agree with the experimental single-particle spectrum in Sn as well as
the Nilsson spin-orbit parameter and orbit-orbit parameter thus
extracted, but remarkably differ from the traditional Nilsson parameters.
Furthermore, the present results provide a guideline for the isospin dependence
of the Nilsson parameters.Comment: 4 pages, 4 figures, Phys. Rev. C in pres
Enhancing User Loyalty through Network Externality: An Empirical Study on B2B Platform
Loyal users are vital to the future of B2B platform with rapid development and intensive competitions. This study examines how network externality, in terms of direct network externality and indirect network externality, enhances B2B platform users\u27 perceived value, and how such perception of value, in turn, influences their satisfaction and loyalty. First, we develop a conceptual model to describe the formation mechanism of user (seller) loyalty on B2B platform. Second, based on literature home and abroad, we develop a questionnaire. With a well-known B2B platform, we get 1,348 valid samples. At last, using structural equation modeling approach, we get the conceptual model fitted. The empirical results show that: network externality can be used as pre-drivers of perceived value thereby affecting user loyalty, but it has no direct influence on user satisfaction
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