843 research outputs found

    An integrated method for cancer classification and rule extraction from microarray data

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    Different microarray techniques recently have been successfully used to investigate useful information for cancer diagnosis at the gene expression level due to their ability to measure thousands of gene expression levels in a massively parallel way. One important issue is to improve classification performance of microarray data. However, it would be ideal that influential genes and even interpretable rules can be explored at the same time to offer biological insight

    Bifurcation Analysis of the Eigenstructure of the Discrete Single-curl Operator in Three-dimensional Maxwell's Equations with Pasteur Media

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    This paper focuses on studying the bifurcation analysis of the eigenstructure of the γ\gamma-parameterized generalized eigenvalue problem (γ\gamma-GEP) arising in three-dimensional (3D) source-free Maxwell's equations with Pasteur media, where γ\gamma is the magnetoelectric chirality parameter. For the weakly coupled case, namely, γ<γ\gamma < \gamma_{*} \equiv critical value, the γ\gamma-GEP is positive definite, which has been well-studied by Chern et.\ al, 2015. For the strongly coupled case, namely, γ>γ\gamma > \gamma_{*}, the γ\gamma-GEP is no longer positive definite, introducing a totally different and complicated structure. For the critical strongly coupled case, numerical computations for electromagnetic fields have been presented by Huang et.\ al, 2018. In this paper, we build several theoretical results on the eigenstructure behavior of the γ\gamma-GEPs. We prove that the γ\gamma-GEP is regular for any γ>0\gamma > 0, and the γ\gamma-GEP has 2×22 \times 2 Jordan blocks of infinite eigenvalues at the critical value γ\gamma_{*}. Then, we show that the 2×22 \times 2 Jordan block will split into a complex conjugate eigenvalue pair that rapidly goes down and up and then collides at some real point near the origin. Next, it will bifurcate into two real eigenvalues, with one moving toward the left and the other to the right along the real axis as γ\gamma increases. A newly formed state whose energy is smaller than the ground state can be created as γ\gamma is larger than the critical value. This stunning feature of the physical phenomenon would be very helpful in practical applications. Therefore, the purpose of this paper is to clarify the corresponding theoretical eigenstructure of 3D Maxwell's equations with Pasteur media.Comment: 26 pages, 5 figure

    Direction controllable linearly polarized laser from a dye-doped cholesteric liquid crystal

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    We demonstrate a direction controllable linearly polarized laser from a dye-doped cholesteric liquid crystal (CLC) in a homogeneous cell coated with a metallic mirror on the inner side of a glass substrate. Due to coherent superposition of two orthogonal polarization states, the output laser light becomes linearly polarized and its output energy is greatly enhanced. Moreover, the linear polarization direction angle is proportional to the product of the CLC effective birefringence and cell gap. Hence direction tunable laser devices can be demonstrated by controlling the cell gap and the operating temperature

    Evidence for formation of multi-quantum dots in hydrogenated graphene.

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    We report the experimental evidence for the formation of multi-quantum dots in a hydrogenated single-layer graphene flake. The existence of multi-quantum dots is supported by the low-temperature measurements on a field effect transistor structure device. The resulting Coulomb blockade diamonds shown in the color scale plot together with the number of Coulomb peaks exhibit the characteristics of the so-called 'stochastic Coulomb blockade'. A possible explanation for the formation of the multi-quantum dots, which is not observed in pristine graphene to date, was attributed to the impurities and defects unintentionally decorated on a single-layer graphene flake which was not treated with the thermal annealing process. Graphene multi-quantum dots developed around impurities and defect sites during the hydrogen plasma exposure process.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are

    Probing onset of strong localization and electron-electron interactions with the presence of direct insulator-quantum Hall transition

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    We have performed low-temperature transport measurements on a disordered two-dimensional electron system (2DES). Features of the strong localization leading to the quantum Hall effect are observed after the 2DES undergoes a direct insulator-quantum Hall transition with increasing the perpendicular magnetic field. However, such a transition does not correspond to the onset of strong localization. The temperature dependences of the Hall resistivity and Hall conductivity reveal the importance of the electron-electron interaction effects to the observed transition in our study.Comment: 9 pages, 4 figure

    A Null Space Free Jacobi--Davidson Iteration for Maxwell's Operator

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