2,657 research outputs found

    The Method of Moments and the Energy Levels of Molecules and Solids

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    The method of moments is used to derive the energy levels of a representative series of molecules, crystalline and noncrysta-1- line solids. It provides a direct link between the density of states of the eigenvalue spectrum and the connectivity and topology of the molecular or solid state network

    Simulation of the integrated controller of the anti-lock braking system

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    Author name used in this publication: K. W. E. ChengVersion of RecordPublishe

    Bivariate spline interpolation with optimal approximation order

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    Let be a triangulation of some polygonal domain f c R2 and let S9 (A) denote the space of all bivariate polynomial splines of smoothness r and degree q with respect to A. We develop the first Hermite-type interpolation scheme for S9 (A), q >_ 3r + 2, whose approximation error is bounded above by Kh4+i, where h is the maximal diameter of the triangles in A, and the constant K only depends on the smallest angle of the triangulation and is independent of near-degenerate edges and nearsingular vertices. Moreover, the fundamental functions of our scheme are minimally supported and form a locally linearly independent basis for a superspline subspace of Sr, (A). This shows that the optimal approximation order can be achieved by using minimally supported splines. Our method of proof is completely different from the quasi-interpolation techniques for the study of the approximation power of bivariate splines developed in [71 and [181

    p50–NF-ÎșB Complexes Partially Compensate for the Absence of RelB: Severely Increased Pathology in p50−/−relB−/−Double-knockout Mice

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    RelB-deficient mice (relB−/−) have a complex phenotype including multiorgan inflammation and hematopoietic abnormalities. To examine whether other NF-ÎșB/Rel family members are required for the development of this phenotype or have a compensatory role, we have initiated a program to generate double-mutant mice that are deficient in more than one family member. Here we report the phenotypic changes in relB−/− mice that also lack the p50 subunit of NFÎșB (p50−/−). The inflammatory phenotype of p50−/−relB−/− double-mutant mice was markedly increased in both severity and extent of organ involvement, leading to premature death within three to four weeks after birth. Double-knockout mice also had strongly increased myeloid hyperplasia and thymic atrophy. Moreover, B cell development was impaired and, in contrast to relB−/− single knockouts, B cells were absent from inflammatory infiltrates. Both p50−/− and heterozygous relB−/+ animals are disease-free. In the absence of the p50, however, relB−/+ mice (p50−/−relB−/+) had a mild inflammatory phenotype and moderate myeloid hyperplasia. Neither elevated mRNA levels of other family members, nor increased ÎșB-binding activities of NF-ÎșB/Rel complexes could be detected in single- or double-mutant mice compared to control animals. These results indicate that the lack of RelB is, in part, compensated by other p50-containing complexes and that the “classical” p50-RelA–NF-ÎșB activity is not required for the development of the inflammatory phenotype

    Early Assessment of Tumor Response to Radiation Therapy using High-Resolution Quantitative Microvascular Ultrasound Imaging

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    Measuring changes in tumor volume using anatomical imaging weeks to months post radiation therapy (RT) is currently the clinical standard for indicating treatment response to RT. For patients whose tumors do not respond successfully to treatment, this approach is suboptimal as timely modification of the treatment approach may lead to better clinical outcomes. We propose to use tumor microvasculature as a biomarker for early assessment of tumor response to RT. Acoustic angiography is a novel contrast ultrasound imaging technique that enables high-resolution microvascular imaging and has been shown to detect changes in microvascular structure due to cancer growth. Data suggest that acoustic angiography can detect longitudinal changes in the tumor microvascular environment that correlate with RT response

    Local edge modes in doped cuprates with checkerboard polaronic heterogeneity

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    We study a periodic polaronic system, which exhibits a nanoscale superlattice structure, as a model for hole-doped cuprates with checkerboard-like heterogeneity, as has been observed recently by scanning tunneling microscopy (STM). Within this model, the electronic and phononic excitations are investigated by applying an unrestricted Hartree-Fock and a random phase approximation (RPA) to a multiband Peierls-Hubbard Hamiltonian in two dimensions

    Imaging and Dynamics of Light Atoms and Molecules on Graphene

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    Observing the individual building blocks of matter is one of the primary goals of microscopy. The invention of the scanning tunneling microscope [1] revolutionized experimental surface science in that atomic-scale features on a solid-state surface could finally be readily imaged. However, scanning tunneling microscopy has limited applicability due to restrictions, for example, in sample conductivity, cleanliness, and data aquisition rate. An older microscopy technique, that of transmission electron microscopy (TEM) [2, 3] has benefited tremendously in recent years from subtle instrumentation advances, and individual heavy (high atomic number) atoms can now be detected by TEM [4 - 7] even when embedded within a semiconductor material [8, 9]. However, detecting an individual low atomic number atom, for example carbon or even hydrogen, is still extremely challenging, if not impossible, via conventional TEM due to the very low contrast of light elements [2, 3, 10 - 12]. Here we demonstrate a means to observe, by conventional transmision electron microscopy, even the smallest atoms and molecules: On a clean single-layer graphene membrane, adsorbates such as atomic hydrogen and carbon can be seen as if they were suspended in free space. We directly image such individual adatoms, along with carbon chains and vacancies, and investigate their dynamics in real time. These techniques open a way to reveal dynamics of more complex chemical reactions or identify the atomic-scale structure of unknown adsorbates. In addition, the study of atomic scale defects in graphene may provide insights for nanoelectronic applications of this interesting material.Comment: 9 pages manuscript and figures, 9 pages supplementary informatio

    An algorithm to remove noise from locomotive bearing vibration signal based on self-adaptive EEMD filter

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    An improved ensemble empirical mode decomposition (EEMD) algorithm is described in this work, in which the sifting and ensemble number are self-adaptive. In particular, the new algorithm can effectively avoid the mode mixing problem. The algorithm has been validated with a simulation signal and locomotive bearing vibration signal. The results show that the proposed self-adaptive EEMD algorithm has a better filtering performance compared with the conventional EEMD. The filter results further show that the feature of the signal can be distinguished clearly with the proposed algorithm, which implies that the fault characteristics of the locomotive bearing can be detected successfully

    On-line scheme for parameter estimation of nonlinear lithium ion battery equivalent circuit models using the simplified refined instrumental variable method for a modified Wiener continuous-time model

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    The accuracy of identifying the parameters of models describing lithium ion batteries (LIBs) in typical battery management system (BMS) applications is critical to the estimation of key states such as the state of charge (SoC) and state of health (SoH). In applications such as electric vehicles (EVs) where LIBs are subjected to highly demanding cycles of operation and varying environmental conditions leading to non-trivial interactions of ageing stress factors, this identification is more challenging. This paper proposes an algorithm that directly estimates the parameters of a nonlinear battery model from measured input and output data in the continuous time-domain. The simplified refined instrumental variable method is extended to estimate the parameters of a Wiener model where there is no requirement for the nonlinear function to be invertible. To account for nonlinear battery dynamics, in this paper, the typical linear equivalent circuit model (ECM) is enhanced by a block-oriented Wiener configuration where the nonlinear memoryless block following the typical ECM is defined to be a sigmoid static nonlinearity. The nonlinear Weiner model is reformulated in the form of a multi-input, single-output linear model. This linear form allows the parameters of the nonlinear model to be estimated using any linear estimator such as the well-established least squares (LS) algorithm. In this paper, the recursive least square (RLS) method is adopted for online parameter estimation. The approach was validated on experimental data measured from an 18650-type Graphite/Lithium-Nickel-Cobalt-Aluminium-Oxide (C6/LiNiCoAlO2) lithium-ion cell. A comparison between the results obtained by the proposed method and by nonparametric frequency-based approaches for obtaining the model parameters is presented. It is shown that although both approaches give similar estimates, the advantages of the proposed method are (i) the simplicity by which the algorithm can be employed on-line for updating nonlinear equivalent circuit model (NL-ECM) parameters and (ii) the improved convergence efficiency of the on-line estimation

    Statistical Properties of the Reflectance and Transmittance of an Amplifying Random Media

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    Statistical properties of the transmittance (TT) and reflectance (RR) of an amplifying layer with one-dimensional disorder are investigated analytically. Whereas the transmittance at typical realizations decreases exponentially with the layer thickness LL just as it does in absorbing media, the average ⟹T⟩\left\langle T\right\rangle and ⟹R⟩\left\langle R\right\rangle \ are shown to be infinite even for finite LL due to the contribution of low-probable resonant realizations corresponding to the non-Gaussian tail of the distribution of ln⁥T\ln T. This tail differs drastically from that in the case of absorption. The physical meaning of typical and resonant realizations is discussed.Comment: 5 pages (RevTeX
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