18,912 research outputs found

    Innovation Institution and Spatial Transfer of Energy Industry: The Case of Jiangsu Province, China

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    This study aims to explore the effect of innovation institution on spatial transfer of energy industry in Jiangsu, China. We focus on the disparity of innovation and energy industry, and analyze the spatial transfer difference in different types of energy industry, rather than view energy industry as a whole. The study demonstrates the spatial change of energy industry at regional level and maps the spatial pattern at city level. The study chooses intellectual property rights (IPRs) protection intensity, authorization patents and local research and development (R&D) investment as the proxy of innovation. Using official data and employing panel fixed-effect model at city-industry level, we conclude (a) innovation abilities significantly influence the spatial transfer of energy industry in Jiangsu. Especially, due to the different time, IPRs protection, patent counts, and R&D investment have different effects on different regions in Jiangsu; (b) 2010 is an important turning point for energy industry development in Jiangsu, and after 2010, the energy industry begins to shift to the middle and northern Jiangsu, whereas the spatial pattern of energy industry in coastal cities is basically unchanged; (c) there is a great difference between the regions in Jiangsu Province, and industrial upgrading has not been achieved in northern Jiangsu

    Specific heat and thermal conductivity of ferromagnetic magnons in Yttrium Iron Garnet

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    The specific heat and thermal conductivity of the insulating ferrimagnet Y3_3Fe5_5O12_{12} (Yttrium Iron Garnet, YIG) single crystal were measured down to 50 mK. The ferromagnetic magnon specific heat CCm_m shows a characteristic T1.5T^{1.5} dependence down to 0.77 K. Below 0.77 K, a downward deviation is observed, which is attributed to the magnetic dipole-dipole interaction with typical magnitude of 104^{-4} eV. The ferromagnetic magnon thermal conductivity κm\kappa_m does not show the characteristic T2T^2 dependence below 0.8 K. To fit the κm\kappa_m data, both magnetic defect scattering effect and dipole-dipole interaction are taken into account. These results complete our understanding of the thermodynamic and thermal transport properties of the low-lying ferromagnetic magnons.Comment: 5 pages, 5 figure

    A switch element in the autophagy E2 Atg3 mediates allosteric regulation across the lipidation cascade

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    Autophagy depends on the E2 enzyme, Atg3, functioning in a conserved E1-E2-E3 trienzyme cascade that catalyzes lipidation of Atg8-family ubiquitin-like proteins (UBLs). Molecular mechanisms underlying Atg8 lipidation remain poorly understood despite association of Atg3, the E1 Atg7, and the composite E3 Atg12-Atg5-Atg16 with pathologies including cancers, infections and neurodegeneration. Here, studying yeast enzymes, we report that an Atg3 element we term E123IR (E1, E2, and E3-interacting region) is an allosteric switch. NMR, biochemical, crystallographic and genetic data collectively indicate that in the absence of the enzymatic cascade, the Atg3(E123IR) makes intramolecular interactions restraining Atg3's catalytic loop, while E1 and E3 enzymes directly remove this brace to conformationally activate Atg3 and elicit Atg8 lipidation in vitro and in vivo. We propose that Atg3's E123IR protects the E2 similar to UBL thioester bond from wayward reactivity toward errant nucleophiles, while Atg8 lipidation cascade enzymes induce E2 active site remodeling through an unprecedented mechanism to drive autophagy

    Chromospheric Evaporation in an X1.0 Flare on 2014 March 29 Observed with IRIS and EIS

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    Chromospheric evaporation refers to dynamic mass motions in flare loops as a result of rapid energy deposition in the chromosphere. These have been observed as blueshifts in X-ray and extreme-ultraviolet (EUV) spectral lines corresponding to upward motions at a few tens to a few hundreds of km/s. Past spectroscopic observations have also revealed a dominant stationary component, in addition to the blueshifted component, in emission lines formed at high temperatures (~10 MK). This is contradictory to evaporation models predicting predominant blueshifts in hot lines. The recently launched Interface Region Imaging Spectrograph (IRIS) provides high resolution imaging and spectroscopic observations that focus on the chromosphere and transition region in the UV passband. Using the new IRIS observations, combined with coordinated observations from the EUV Imaging Spectrometer, we study the chromospheric evaporation process from the upper chromosphere to corona during an X1.0 flare on 2014 March 29. We find evident evaporation signatures, characterized by Doppler shifts and line broadening, at two flare ribbons separating from each other, suggesting that chromospheric evaporation takes place in successively formed flaring loops throughout the flare. More importantly, we detect dominant blueshifts in the high temperature Fe XXI line (~10 MK), in agreement with theoretical predictions. We also find that, in this flare, gentle evaporation occurs at some locations in the rise phase of the flare, while explosive evaporation is detected at some other locations near the peak of the flare. There is a conversion from gentle to explosive evaporation as the flare evolves.Comment: ApJ in pres

    Quantum criticality and nodal superconductivity in the FeAs-based superconductor KFe2As2

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    The in-plane resistivity ρ\rho and thermal conductivity κ\kappa of FeAs-based superconductor KFe2_2As2_2 single crystal were measured down to 50 mK. We observe non-Fermi-liquid behavior ρ(T)T1.5\rho(T) \sim T^{1.5} at Hc2H_{c_2} = 5 T, and the development of a Fermi liquid state with ρ(T)T2\rho(T) \sim T^2 when further increasing field. This suggests a field-induced quantum critical point, occurring at the superconducting upper critical field Hc2H_{c_2}. In zero field there is a large residual linear term κ0/T\kappa_0/T, and the field dependence of κ0/T\kappa_0/T mimics that in d-wave cuprate superconductors. This indicates that the superconducting gaps in KFe2_2As2_2 have nodes, likely d-wave symmetry. Such a nodal superconductivity is attributed to the antiferromagnetic spin fluctuations near the quantum critical point.Comment: 4 pages, 4 figures - replaces arXiv:0909.485

    Nodeless superconductivity in Ca3Ir4Sn13: evidence from quasiparticle heat transport

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    We report resistivity ρ\rho and thermal conductivity κ\kappa measurements on Ca3_3Ir4_4Sn13_{13} single crystals, in which superconductivity with Tc7T_c \approx 7 K was claimed to coexist with ferromagnetic spin-fluctuations. Among three crystals, only one crystal shows a small hump in resistivity near 20 K, which was previously attributed to the ferromagnetic spin-fluctuations. Other two crystals show the ρT2\rho \sim T^2 Fermi-liquid behavior at low temperature. For both single crystals with and without the resistivity anomaly, the residual linear term κ0/T\kappa_0/T is negligible in zero magnetic field. In low fields, κ0(H)/T\kappa_0(H)/T shows a slow field dependence. These results demonstrate that the superconducting gap of Ca3_3Ir4_4Sn13_{13} is nodeless, thus rule out nodal gap caused by ferromagnetic spin-fluctuations.Comment: 5 pages, 4 figure

    Solar flare hard X-ray spikes observed by RHESSI: a case study

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    In this paper, we analyze hard X-ray spikes observed by RHESSI to understand their temporal, spectral, and spatial properties. A recently developed demodulation code was applied to hard X-ray light curves in several energy bands observed by RHESSI. Hard X-ray spikes were selected from the demodulated flare light curves. We measured the spike duration, the energy-dependent time delay, and count spectral index of these spikes. We also located the hard X-ray source emitting these spikes from RHESSI mapping that was coordinated with imaging observations in visible and UV wavelengths. We identify quickly varying structures of <1 s during the rise of hard X-rays in five flares. These hard X-ray spikes can be observed at photon energies over 100 keV. They exhibit sharp rise and decay with a duration (FWHM) of less than 1 s. Energy-dependent time lags are present in some spikes. It is seen that the spikes exhibit harder spectra than underlying components, typically by 0.5 in the spectral index when they are fitted to power-law distributions. RHESSI clean maps at 25-100 keV with an integration of 2 s centered on the peak of the spikes suggest that hard X-ray spikes are primarily emitted by double foot-point sources in magnetic fields of opposite polarities. With the RHESSI mapping resolution of ~ 4 arsec, the hard X-ray spike maps do not exhibit detectable difference in the spatial structure from sources emitting underlying components. Coordinated high-resolution imaging UV and infrared observations confirm that hard X-ray spikes are produced in magnetic structures embedded in the same magnetic environment of the underlying components. The coordinated high-cadence TRACE UV observations of one event possibly reveal new structures on spatial scales <1-2 arsec at the time of the spike superposed on the underlying component. They are probably sources of hard X-ray spikes.Comment: 20 pages, 11 figure
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