1,423 research outputs found

    Catalytic partial oxidation of methane to synthesis gas over ZRO2-based defective oxides

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    the work presented in this thesis provides both fundamental scientific knowledge as well as a new technical dual-bed concept for synthesis\ud gas production via catalytic partial oxidation of methane over defective ZrO2-based oxides

    The Wood Properties of an Intergeneric Hybrid - Taxodiomeria peizhongii (Taxodium mucronatum × Cryptomeria fortunei)

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    Taxodiomeria peizhongii is an intergeneric hybrid between Taxodium mucronatum and Cryptomeria fortunei. By more than 30 years investigation, it is found that the hybrid is well suited for the site and climate of Shanghai area, and it will be one of the main landscape trees in near few years. So it is necessary to know its basic wood properties. In this research, we harvested 6 sample trees of Taxodiomeria peizhongii and studied the elementary wood properties. The results showed that its mean annual ring width was 7.0mm, mean basic density 0.32g/cm3, and the mean percentage of latewood 24.3%. The mean treacheid length of latewood was 3.1mm, and mean treacheid width 35.1μm. Compared with other usual coniferous trees, the values of these indices were at a medium level. The period of juvenile wood was about 15 years, and the fast growing period appeared in first 10 years. The basic density, altering less in radial growth, showed a significant minus relation with annual ring width. The percentage of latewood did not related to wood density.OtherShinshu University International Symposium 2010 : Sustainable Agriculture and Environment : Asian Networks II  信州大学国際シンポジウム2010 : 持続的農業と環境 : アジアネットワークII ― アジアネットワークの発展をめざして―. 信州大学農学部, 2010, 65-70conference pape

    Critical current density and vortex pinning in tetragonal FeS1x_{1-x}Sex_{x} (x=0,0.06x=0,0.06)

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    We report critical current density (JcJ_c) in tetragonal FeS single crystals, similar to iron based superconductors with much higher superconducting critical temperatures (TcT_{c}'s). The JcJ_c is enhanced 3 times by 6\% Se doping. We observe scaling of the normalized vortex pinning force as a function of reduced field at all temperatures. Vortex pinning in FeS and FeS0.94_{0.94}Se0.06_{0.06} shows contribution of core-normal surface-like pinning. Reduced temperature dependence of JcJ_c indicates that dominant interaction of vortex cores and pinning centers is via scattering of charge carriers with reduced mean free path (δ\deltall), in contrast to Kx_xFe2y_{2-y}Se2_2 where spatial variations in TcT_{c} (δ\deltaTcT_{c}) prevails.Comment: 5 pages, 4 figure

    A Bayesian method for linear, inequality-constrained adjustment and its application to GPS positioning

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    One of the typical approaches to linear, inequality-constrained adjustment (LICA) is to solve a least-squares (LS) problem subject to the linear inequality constraints. The main disadvantage of this approach is that the statistical properties of the estimate are not easily determined and thus no general conclusions about the superiority of the estimate can be made. A new approach to solving the LICA problem is proposed. The linear inequality constraints are converted into prior information on the parameters with a uniform distribution, and consequently the LICA problem is reformulated into a Bayesian estimation problem. It is shown that the LS estimate of the LICA problem is identical to the Bayesian estimate based on the mode of the posterior distribution. Finally, the Bayesian method is applied to GPS positioning. Results for four field tests show that, when height information is used, the GPS phase ambiguity resolution can be improved significantly and the new approach is feasible

    Kinematic Absolute Positioning with Quad-Constellation GNSS

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    The absolute positioning technique is based on a point positioning mode with a single Global Navigation Satellite System (GNSS) receiver, which has been widely used in many fields such as vehicle navigation and kinematic surveying. For a long period, this positioning technique mainly relies on a single GPS system. With the revitalization of Global Navigation Satellite System (GLONASS) constellation and two newly emerging constellations of BeiDou Navigation Satellite System (BDS) and Galileo, it is now feasible to carry out the absolute positioning with quad-constellation of GPS, GLONASS, BDS, and Galileo. A combination of multi-constellation observations can offer improved reliability, availability, and accuracy for position solutions. In this chapter, combined GPS/GLONASS/BDS/Galileo point positioning models for both traditional single point positioning (SPP) and precise point positioning (PPP) are presented, including their functional and stochastic components. The traditional SPP technique has a positioning accuracy at a meter level, whereas the PPP technique can reach an accuracy of a centimeter level. However, the later relies on the availability of precise ephemeris and needs a long convergence time. Experiments were carried out to assess the kinematic positioning performance in the two different modes. The positioning results are compared among different constellation combinations to demonstrate the advantages of quad-constellation GNSS

    Single point positioning using GPS, GLONASS and BeiDou satellites

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    This paper introduces the Chinese BeiDou satellite system and its comparison with the actual completed American GPS and the Russian GLONASS systems. The actual BeiDou system consists of 14 satellites covering totally the Asia -Pacific area. A Single Point Positioning (SPP) test has been realised in Changsha, Hunan province, China, to show the advantage of using combined pseud o- range solutions from these 3 satellite navigation systems especially in obstructed sites. The test shows that, with an elevation mask angle of 10 ° , the accuracy is improved by about 20% in hor i- zontal coordinates and nearly 50% in the vertical component using the simultaneous observa tions of the 3 systems compared to the GPS/GLONASS solution. For the processing with an elev ation mask angle of 30 ° , most of the time less than 4 GPS satellites were available for the GPS- only case and no solution was possible. However, in this difficult situation, the combined GPS/GLON ASS/ BeiDou solutions provided an accuracy (rms values) of about 5 m

    A New Method for Superresolution Image Reconstruction Based on Surveying Adjustment

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    A new method for superresolution image reconstruction based on surveying adjustment method is described in this paper. The main idea of such new method is that a sequence of low-resolution images are taken firstly as observations, and then observation equations are established for the superresolution image reconstruction. The gray function of the object surface can be found by using surveying adjustment method from the observation equations. High-resolution pixel value of the corresponding area can be calculated by using the gray function. The results show that the proposed algorithm converges much faster than that of conventional superresolution image reconstruction method. By using the new method, the visual feeling of reconstructed image can be greatly improved compared to that of iterative back projection algorithm, and its peak signal-to-noise ratio can also be improved by nearly 1 dB higher than the projection onto convex sets algorithm. Furthermore, this method can successfully avoid the ill-posed problems in reconstruction process
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