776 research outputs found

    Spectral high resolution feature selection for retrieval of combustion temperature profiles

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    Proceeding of: 7th International Conference on Intelligent Data Engineering and Automated Learning, IDEAL 2006 (Burgos, Spain, September 20-23, 2006)The use of high spectral resolution measurements to obtain a retrieval of certain physical properties related with the radiative transfer of energy leads a priori to a better accuracy. But this improvement in accuracy is not easy to achieve due to the great amount of data which makes difficult any treatment over it and it's redundancies. To solve this problem, a pick selection based on principal component analysis has been adopted in order to make the mandatory feature selection over the different channels. In this paper, the capability to retrieve the temperature profile in a combustion environment using neural networks jointly with this spectral high resolution feature selection method is studied.Publicad

    Coordinating Pricing and Empty Container Repositioning in Two-Depot Shipping Systems

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    This paper studies joint decisions on pricing and empty container repositioning in two- depot shipping services with stochastic shipping demand. We formulate the problem as a stochastic dynamic programming (DP) model. The exact DP may have a high-dimensional state space due to in-transit containers. To cope with the curse of dimensionality, we develop an approximate model where the number of in-transit containers on each vessel is approxi- mated with a fixed container flow predetermined by solving a static version of the problem. Moreover, we show that the approximate value function is L♮-concave, thereby characterizing the structure of the optimal control policy for the approximate model. With the upper bound obtained by solving the information relaxation-based dual of the exact DP, we numerically show that the control policies generated from our approximate model are close to optimal when transit times span multiple periods

    Interface engineering of graphene/copper matrix composites decorated with tungsten carbide for enhanced physico-mechanical properties

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    For metal matrix composites (MMCs), introduction of low-dimensional nano-carbon materials (NCMs) into three dimensional metallic matrix is commonly applied to enhance mechanical and physical properties of metals and thus significantly extend their wide range applications. However, the interfaces between the NCMs and metal matrix are always a major issue for achieving the best enhancement effects. In this paper, we investigated interfacial structures of graphene nanoplates (GNPs) reinforced Cu matrix composites fabricated using a simple and industrially scalable strategy, through integration of interface engineering design methodology and a spark plasma sintering (SPS) process. We then systematically evaluated their physico-mechanical properties, interfacial characteristics and strengthening mechanisms. The in-situ formed WxCy nano-layers and carbide nanoparticles on the surfaces of GNPs and near the interfaces of Cu grains promote strong interfacial bonding and improves the cohesive strength of Cu based nanocomposites. The GNPs-W/Cu composites show a good balance between strength and electrical conductivity. Their 0.2% yield strength and ultimate tensile strength have been improved up to 239.13% (112.73%) and 197.76% (72.51%), respectively, when compared with those of pure copper (or GNPs/Cu composites). Electrical conductivity of GNPs-W/Cu composites shows no apparent changes after the addition of the GNPs. The dislocation strengthening, refinement strengthening and load transfer strengthening were achieved simultaneously through the engineered interfaces in GNPs-W/Cu matrix composites. This work has provided a new strategy to fabricate high-performance NCMs enhanced MMCs by using the interface engineering methodology

    Effect of tensor couplings in a relativistic Hartree approach for finite nuclei

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    The relativistic Hartree approach describing the bound states of both nucleons and anti-nucleons in finite nuclei has been extended to include tensor couplings for the ω\omega- and ρ\rho-meson. After readjusting the parameters of the model to the properties of spherical nuclei, the effect of tensor-coupling terms rises the spin-orbit force by a factor of 2, while a large effective nucleon mass m/MN0.8m^{*}/M_{N} \approx 0.8 sustains. The overall nucleon spectra of shell-model states are improved evidently. The predicted anti-nucleon spectra in the vacuum are deepened about 20 -- 30 MeV.Comment: 31 pages, 4 postscript figures include

    Measurements of J/psi Decays into 2(pi+pi-)eta and 3(pi+pi-)eta

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    Based on a sample of 5.8X 10^7 J/psi events taken with the BESII detector, the branching fractions of J/psi--> 2(pi+pi-)eta and J/psi-->3(pi+pi-)eta are measured for the first time to be (2.26+-0.08+-0.27)X10^{-3} and (7.24+-0.96+-1.11)X10^{-4}, respectively.Comment: 11 pages, 6 figure

    BESII Detector Simulation

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    A Monte Carlo program based on Geant3 has been developed for BESII detector simulation. The organization of the program is outlined, and the digitization procedure for simulating the response of various sub-detectors is described. Comparisons with data show that the performance of the program is generally satisfactory.Comment: 17 pages, 14 figures, uses elsart.cls, to be submitted to NIM

    Measurement of branching fractions for the inclusive Cabibbo-favored ~K*0(892) and Cabibbo-suppressed K*0(892) decays of neutral and charged D mesons

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    The branching fractions for the inclusive Cabibbo-favored ~K*0 and Cabibbo-suppressed K*0 decays of D mesons are measured based on a data sample of 33 pb-1 collected at and around the center-of-mass energy of 3.773 GeV with the BES-II detector at the BEPC collider. The branching fractions for the decays D+(0) -> ~K*0(892)X and D0 -> K*0(892)X are determined to be BF(D0 -> \~K*0X) = (8.7 +/- 4.0 +/- 1.2)%, BF(D+ -> ~K*0X) = (23.2 +/- 4.5 +/- 3.0)% and BF(D0 -> K*0X) = (2.8 +/- 1.2 +/- 0.4)%. An upper limit on the branching fraction at 90% C.L. for the decay D+ -> K*0(892)X is set to be BF(D+ -> K*0X) < 6.6%
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