7,111 research outputs found

    Laser-induced breakdown spectroscopy in Asia

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    Laser-induced breakdown spectroscopy (LIBS) is an analytical detection technique based on atomic emission spectroscopy to measure the elemental composition. LIBS has been extensively studied and developed due to the non-contact, fast response, high sensitivity, real-time and multi-elemental detection features. The development and applications of LIBS technique in Asia are summarized and discussed in this review paper. The researchers in Asia work on different aspects of the LIBS study in fundamentals, data processing and modeling, applications and instrumentations. According to the current research status, the challenges, opportunities and further development of LIBS technique in Asia are also evaluated to promote LIBS research and its applications

    Heterogeneity in structurally arrested hard spheres

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    When cooled or compressed sufficiently rapidly, a liquid vitrifies into a glassy amorphous state. Vitrification in a dense liquid is associated with jamming of the particles. For hard spheres, the density and degree of order in the final structure depend on the compression rate: simple intuition suggests, and previous computer simulation demonstrates, that slower compression results in states that are both denser and more ordered. In this work, we use the Lubachevsky-Stillinger algorithm to generate a sequence of structurally arrested hard-sphere states by varying the compression rate. We find that while the degree of order, as measured by both bond-orientation and translation order parameters, increases monotonically with decreasing compression rate, the density of the arrested state first increases, then decreases, then increases again, as the compression rate decreases, showing a minimum at an intermediate compression rate. Examination of the distribution of the local order parameters and the distribution of the root-mean-square fluctuation of the particle positions, as well as direct visual inspection of the arrested structures, reveal that they are structurally heterogeneous, consisting of disordered, amorphous regions and locally ordered crystal-like domains. In particular, the low-density arrested states correspond with many interconnected small crystal clusters that form a polycrystalline network interspersed in an amorphous background, suggesting that jamming by the domains may be an important mechanism for these states

    VLBI astrometry of two millisecond pulsars

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    We present astrometric results on two millisecond pulsars, PSR B1257+12 and PSR J1022+1001, as carried out through VLBI. For PSR B1257+12, a model-independent distance of 710−38+43710_{\rm -38}^{\rm +43} pc and proper motion of (μα=46.44±0.08\mu_{\rm \alpha}=46.44\pm0.08 mas/yr, μδ=−84.87±0.32\mu_{\rm \delta}=-84.87\pm0.32 mas/yr) were obtained from 5 epochs of VLBA and 4 epochs of EVN observations, spanning about 2 years. The two dimensional proper motion of PSR J1022+1001 (μα∼−10.13\mu_{\rm \alpha} \sim -10.13 mas/yr, μδ∼16.89\mu_{\delta} \sim 16.89 mas/yr) was also estimated, using 3 epochs of EVN observations. Based on our results, the X-ray efficiency of PSR B1257+12 should be in the same range as other millisecond pulsars, and not as low as previously thought.Comment: Proceedings of IAUS 291 "Neutron Stars and Pulsars: Challenges and Opportunities after 80 years", J. van Leeuwen (ed.); 3 page

    The Performance Optimization of Rolling Piston Compressors Based on CFD Simulation

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    Heterogeneous impacts of renewable energy and environmental patents on CO2 emission - Evidence from the BRIICS

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    The study explores the impacts of renewable energy, environmental patents, economic growth and other variables on the CO2 emission per capita from 2000 to 2013 for the BRIICS countries. Using both the panel OLS methods and panel quantile regression method, we find that the effects of the determinant variables are heterogeneous across quantiles. Specifically, renewable energy supply reduces CO2 emissions per capita, with the strongest effect at the 95th quantile. Development of environmental patents accelerates carbon emissions per capita, but only significantly affects the CO2 emissions per capita at the upper tail of the conditional distribution. GDP per capita enhances CO2 emissions per capita, with the most substantial effect in the 5th quantile. Exports increase carbon emissions per capita with an asymmetric inverted U-sharped impact. Foreign direct investment reduces carbon emissions per capita, but only significantly influences the carbon emissions per capita at the medium and upper of the conditional distribution. Domestic credit to private sectors raises carbon emissions per capita with gradually decreasing impacts along all quantiles. We propose several policy recommendations based on the results
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