573 research outputs found

    Microstructure and Wear Behavior of CoCrFeMnNbNi High-Entropy Alloy Coating by TIG Cladding

    Get PDF
    Alloy cladding coatings are widely prepared on the surface of tools and machines. High-entropy alloys are potential replacements of nickel-, iron-, and cobalt-base alloys in machining due to their excellent strength and toughness. In this work, CoCrFeMnNbNi HEA coating was produced on AISI 304 steel by tungsten inert gas cladding. The microstructure and wear behavior of the cladding coating were studied by X-ray diffraction, scanning electron microscopy, energy dispersive spectrometer, microhardness tester, pin-on-ring wear tester, and 3D confocal laser scanning microscope. The microstructure showed up as a nanoscale lamellar structure matrix which is a face-centered-cubic solid solution and niobium-rich Laves phase. The microhardness of the cladding coating is greater than the structure. The cladding coating has excellent wear resistance under the condition of dry sliding wear, and the microploughing in the worn cladding coating is shallower and finer than the worn structure, which is related to composition changes caused by forming the nanoscale lamellar structure of Laves phase

    pH-Dependent Fluorescent Probe That Can Be Tuned for Cysteine or Homocysteine

    Get PDF
    The very close structural similarities between cysteine and homocysteine present a great challenge to achieve their selective detection using regular fluorescent probes, limiting the biological and pathological studies of these two amino thiols. A coumarin-based fluorescent probe was designed featuring pH-promoted distinct turn-on followed by ratiometric fluorescence responses for Cys and turn-on fluorescence response for Hcy through two different reaction paths. These specific responses demonstrate the activity differences between Cys and Hcy qualitatively for the first time. The probe could also be used for Cys and Hcy imaging in living cells

    Electronic correlations and energy gap in the bilayer nickelate La3_{3}Ni2_{2}O7_{7}

    Full text link
    The discovery of superconductivity with a critical temperature of 80~K in La3_{3}Ni2_{2}O7_{7} under pressure has received enormous attention. La3_{3}Ni2_{2}O7_{7} is not superconducting under ambient pressure but exhibits a density-wave-like transition at T115T^{\ast} \simeq 115~K. Understanding the electronic correlations, charge dynamics and dominant orbitals are important steps towards the mechanism of superconductivity and other instabilities. Here, our optical study shows that La3_{3}Ni2_{2}O7_{7} features strong electronic correlations which significantly reduce the electron's kinetic energy and place it in the proximity of the Mott phase. The low-frequency optical conductivity reveals two Drude components arising from multiple bands dominated by the Ni-dx2y2d_{x^2 - y^2} and Ni-d3z2r2d_{3z^2 - r^2} orbitals at the Fermi level. Above TT^{\ast}, the scattering rates for both Drude components vary linearly with temperature, indicating non-Fermi-liquid behavior which may be associated with spin-fluctuation scattering. Below TT^{\ast}, a gap opens in the Ni-d3z2r2d_{3z^2 - r^2} orbital, suggesting the importance of the Ni-d3z2r2d_{3z^2 - r^2} orbital in the density-wave-like instability. Our experimental results provide key insights into the mechanism of the density-wave-like order and superconductivity in La3_{3}Ni2_{2}O7_{7}.Comment: 26 pages, 4 figures, Comments are welcome and appreciate

    Synthesis and Characterization of Organic Dyes Containing Various Donors and Acceptors

    Get PDF
    New organic dyes comprising carbazole, iminodibenzyl, or phenothiazine moieties, respectively, as the electron donors, and cyanoacetic acid or acrylic acid moieties as the electron acceptors/anchoring groups were synthesized and characterized. The influence of heteroatoms on carbazole, iminodibenzyl and phenothiazine donors, and cyano-substitution on the acid acceptor is evidenced by spectral, electrochemical, photovoltaic experiments, and density functional theory calculations. The phenothiazine dyes show solar-energy-to-electricity conversion efficiency (η) of 3.46–5.53%, whereas carbazole and iminodibenzyl dyes show η of 2.43% and 3.49%, respectively

    Predictors of futile recanalization in basilar artery occlusion patients undergoing endovascular treatment: a post hoc analysis of the ATTENTION trial

    Get PDF
    BackgroundFew studies have focused on factors associated with futile recanalization in patients with an acute basilar artery occlusion (BAO) that was treated with modern endovascular therapy (EVT). The aim of this study was to explore the factors associated with futile recanalization in patients with an acute BAO presented within 12 h.MethodsThis is a post-hoc analysis of the ATTENTION trial (The Trial of Endovascular Treatment of Acute Basilar-Artery Occlusion, ClinicalTrials.gov, number NCT 04751708). Demographics, clinical characteristics, acute stroke workflow interval times, and imaging characteristics were compared between the futile recanalization and favorable recanalization groups. The favorable outcome was defined as a modified Rankin scale (mRS) score of 0–3 at 90 days, successful reperfusion was defined as thrombolysis in cerebral infarction (TICI) 2b and 3 on the final angiogram, and futile recanalization was defined as failure to achieve a favorable outcome despite successful reperfusion. A multivariate analysis was performed to identify the predictors of futile recanalization.ResultsIn total, 185 patients were included in the final analysis: 89 (48.1%) patients had futile recanalization and 96 (51.9%) patients had favorable recanalization. In the multivariable logistic regression analysis, older age (OR 1.04, 95% CI 1.01 to 1.08, p = 0.01) and diabetes mellitus (OR 3.35, 95% CI 1.40 to 8.01, p = 0.007) were independent predictors of futile recanalization.ConclusionFutile recanalization occurred in nearly half of patients with acute BAO following endovascular treatment. Old age and diabetes mellitus were identified as independent predictors of futile recanalization after endovascular therapy for acute BAO

    Some recent studies on hohlraum physics

    Full text link
    Some of our recent studies on hohlraum physics are presented, mainly including simulation study on hohlraum physics experiments on SGIII prototype, the design of Au + U + Au sandwich hohlraum for ignition target, and an initial design of elliptical hohlraum and pertinent drive laser power in order to generate an ignition radiation profile
    corecore