3,088 research outputs found

    Screening for lipase-producing Enterobacter agglomerans for biodiesel catalyzation

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    This paper reports a comprehensive study of screening rapeseed soil sample in Victoria blue solution solid medium, with olive oil as sole carbon source. The lipase of Enterobacter agglomerans which hasthe highest activity was identified. Under the optimum conditions determined, the enzyme activity of this strain reached 39.09 U/mL. The optimal conditions were found to be: initial pH 7.0, agitating at 30°Cfor 48 h, with 2.0% (w/v) lactose as carbon source, 1.5% (w/v) beef extract and 1.0% (w/v) yeast extract as nitrogen source, and 0.1% (w/v) MgSO4·7H2O. Olive oil, sesame oil and tea oil as raw materials can be catalyzed to biodiesel by the lipase of this strain at 30°C and 180 rpm. And the yield reached 54.51% with sesame oil as raw material, even when they contained 92.4% (w/v) water in the starting materials. This strain will potentially serve as a promising alternative lipase for biodiesel production with raw materials containing water

    Dynamical study of the possible molecular state X(3872) with the s-channel one gluon exchange interaction

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    The recently observed X(3872) resonance, which is difficult to be assigned a conventional ccˉc\bar{c} charmonium state in the quark model, may be interpreted as a molecular state. Such a molecular state is a hidden flavor four quark state because of its charmonium-like quantum numbers. The s-channel one gluon exchange is an interaction which only acts in the hidden flavor multi-quark system. In this paper, we will study the X(3872) and other similiar hidden flavor molecular states in a quark model by taking into account of the s-channel one gluon exchange interaction

    Fluctuations of Spatial Patterns as a Measure of Classical Chaos

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    In problems where the temporal evolution of a nonlinear system cannot be followed, a method for studying the fluctuations of spatial patterns has been developed. That method is applied to well-known problems in deterministic chaos (the logistic map and the Lorenz model) to check its effectiveness in characterizing the dynamical behaviors. It is found that the indices μq\mu _q are as useful as the Lyapunov exponents in providing a quantitative measure of chaos.Comment: 10 pages + 7 figures (in ps file), LaTex, Submitted to Phys. Rev.

    Semisolid processing characteristics of AM series Mg alloys by rheo-diecasting

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    The official published version of this Article can be found at the link below - Copyright @ 2006 ASM InternationalAn investigation has been made into the solidification behavior and microstructural evolution of AM50, AM70, and AM90 alloys during rheo-diecasting, their processibility, and the resulting mechanical properties. It was found that solidification of AM series alloys under intensive melt shearing in the unique twin-screw slurry maker during rheo-diecasting gave rise to numerous spheroidal primary magnesium (Mg) particles that were uniformly present in the microstructure. As a result, the network of the beta-Mg17Al12 phase was consistently interrupted by these spheroidal and ductile particles. Such a microstructure reduced the obstacle of deformation and the harmfulness of the beta-Mg17Al12 network on ductility, and therefore improved the ductility of rheo-diecast AM alloys. It was shown that, even with 9 wt pct Al, the elongation of rheo-diecast AM90 still achieved (9 +/- 1.2) pct. Rheodiecasting thus provides an attractive processing route for upgrading the alloy specification of AM series alloys by increasing the aluminum (Al) content while ensuring ductility. Assessment of the processibility of AM series alloys for semisolid processing showed that high Al content AM series alloys are more suitable for rheo-diecasting than low Al content alloys, because of the lower sensitivity of solid fraction to temperature, the lower liquidus temperature, and the smaller interval between the semisolid processing temperature and the complete solidification temperature.This work is supported by the EPSR

    Trigger efficiencies at BES III

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    Trigger efficiencies at BES III were determined for both the J/psi and psi' data taking of 2009. Both dedicated runs and physics datasets are used; efficiencies are presented for Bhabha-scattering events, generic hadronic decay events involving charged tracks, dimuon events and psi' -> pi+pi-J/psi, J/psi -> l+l- events (l an electron or muon). The efficiencies are found to lie well above 99% for all relevant physics cases, thus fulfilling the BES III design specifications.Comment: 6 pages, 4 figure

    Temporal evolution of depolarization and magnetic field of FRB 20201124A

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    Fast radio bursts (FRBs) are energetic millisecond phenomena in radio band. Polarimetric studies of repeating FRBs indicate that many of these sources occupy extreme and complex magneto-ionized environments. Recently, a frequency-dependent depolarization has been discovered in several repeating FRBs. However, the temporal evolution of polarization properties is limited by the burst rate and observational cadence of telescopes. In this letter, the temporal evolution of depolarization in repeating FRB 20201124A is explored. Using the simultaneous variation of rotation measure and dispersion measure, we also measure the strength of a magnetic field parallel to the line-of-sight. The strength ranges from a few μG\mu {\rm G} to 103 μG10^3\ \mu {\rm G}. In addition, we find that the evolution of depolarization and magnetic field traces the evolution of rotation measure. Our result supports that the variation of depolarization, rotation measure and the magnetic field are determined by the same complex magneto-ionized screen surrounding the FRB source. The derived properties of the screen are consistent with the wind and the decretion disk of a massive star.Comment: 9 pages, 3 figures, 1 table, accept for publication in ApJ

    FreeROI: an integrated toolbox for region of interest definition and visualization

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    With the increasing knowledge for the topography of brain function, neuroimaging studies are moving away from traditional brain mapping towards investigating the response properties of specific brain regions. As a result, region of interest (ROI) approach, which allows one to ask how a region responds to a range of situations and tasks, become an important methodology in neuroimaging. The FreeROI is designed to help ROI analysis by providing versatile tools for defining/manipulating ROIs and calculating a summary time course from the region data. A pipeline for handling big dataset is also included

    A Cellular Automata Model with Probability Infection and Spatial Dispersion

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    In this article, we have proposed an epidemic model by using probability cellular automata theory. The essential mathematical features are analyzed with the help of stability theory. We have given an alternative modelling approach for the spatiotemporal system which is more realistic and satisfactory from the practical point of view. A discrete and spatiotemporal approach are shown by using cellular automata theory. It is interesting to note that both size of the endemic equilibrium and density of the individual increase with the increasing of the neighborhood size and infection rate, but the infections decrease with the increasing of the recovery rate. The stability of the system around the positive interior equilibrium have been shown by using suitable Lyapunov function. Finally experimental data simulation for SARS disease in China and a brief discussion conclude the paper
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