We investigate the weak and strong deflection gravitational lensing by a quantum deformed Schwarzschild black hole and find their observables. These lensing observables are evaluated and the ...detectability of the quantum deformation is assessed, after assuming the supermassive black holes Sgr A* and M87* respectively in the Galactic Center and at the center of M87 as the lenses. We also intensively compare these findings with those of a renormalization group improved Schwarzschild black hole and an asymptotically safe black hole. We find that, among these black holes, it is most likely to test the quantum deformed Schwarzschild black hole via its weak deflection lensing observables in the foreseen future.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Weak and strong deflection gravitational lensing by a renormalization group improved Schwarzschild black hole is investigated and its observables are found. By taking the supermassive black holes Sgr ...A* and M87* respectively in the Galactic Center and at the center of M87 as lenses, we estimate these observables and analyse possibility of detecting this quantum improvement. It is not feasible to distinguish such a black hole by most observables in the near future except for the apparent size of the shadow. We also note that directly using measured shadow of M87* to constrain this quantum effect requires great care.
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Time delay of the photons coupled to the Weyl tensor in a regular phantom black hole is investigated in both weak and strong deflection gravitational lensing. We find that the time delay in the weak ...deflection lensing strongly depends on the phantom hair while the delay in the strong deflection lensing is significantly affected by the hair and the strength of the coupling. We suggest that it is necessary to measure these two kind of time signals for fully understanding and distinguishing such an interaction beyond the standard Einstein–Maxwell theory.
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Electrochemical carbon dioxide (CO2) reduction can in principle convert carbon emissions to fuels and value-added chemicals, such as hydrocarbons and alcohols, using renewable energy, but the ...efficiency of the process is limited by its sluggish kinetics1,2. Molecular catalysts have well defined active sites and accurately tailorable structures that allow mechanism-based performance optimization, and transition-metal complexes have been extensively explored in this regard. However, these catalysts generally lack the ability to promote CO2 reduction beyond the two-electron process to generate more valuable products1,3. Here we show that when immobilized on carbon nanotubes, cobalt phthalocyanine-used previously to reduce CO2 to primarily CO-catalyses the six-electron reduction of CO2 to methanol with appreciable activity and selectivity. We find that the conversion, which proceeds via a distinct domino process with CO as an intermediate, generates methanol with a Faradaic efficiency higher than 40 per cent and a partial current density greater than 10 milliamperes per square centimetre at -0.94 volts with respect to the reversible hydrogen electrode in a near-neutral electrolyte. The catalytic activity decreases over time owing to the detrimental reduction of the phthalocyanine ligand, which can be suppressed by appending electron-donating amino substituents to the phthalocyanine ring. The improved molecule-based electrocatalyst converts CO2 to methanol with considerable activity and selectivity and with stable performance over at least 12 hours.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Abstract Determining the mass of neutron stars is crucial for understanding their formation, evolution, and interior structure. Currently, only a few dozen neutron stars have had their masses ...measured, and most of them belong to binary systems. However, there are a huge number of isolated neutron stars with unknown masses. Microlensing events with neutron stars provide unique opportunities for knowing these compact objects. Astrometric microlensing with a background source lensed by a neutron star might be used to determine the neutron star's mass by measuring the deviation of the motion of the centroid of the images from its unlensed one. We search and predict these recent and future events based on the Australia Telescope National Facility Pulsar Catalog and Gaia DR3. We find 60 candidate astrometric microlensing events caused by neutron stars and the probability distributions of their observables by the Monte Carlo sampling. We also find four candidate “timing microlensing” events with a pulsar lensed by a foreground object that might be detected by timing measurements. While some of these events may be verified by future astrometric missions or pulsar-timing observations, we note that our prediction of these events is significantly restricted by the uncertainties of the available astrometric and timing measurements after assessing and comparing our results with previous works.
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•A novel TiO2/g-C3N4-PS system was proposed for micropollutant degradation.•The TiO2/g-C3N4-PS system exhibits a high efficiency, nonselectivity and great stability.•The effects of ...different reaction conditions on the degradation rate of AAP were systematically studied.•The addition of PS greatly improved the degradation efficiency and oxidizing performance of the TiO2/g-C3N4 system.•The photocatalytic mechanism in the TiO2/g-C3N4-PS system was proposed.
A novel TiO2/g-C3N4-PS system was proposed, in which a TiO2/g-C3N4 heterojunction was used to activate persulfate (PS) to enhance pollutant photodegradation under visible-light irradiation. In this study, the TiO2/g-C3N4 photocatalyst was synthesized by a simple calcination method, and acetaminophen (AAP) was chosen as a model pollutant to test the degradation efficiency of the photocatalytic system. The TiO2/g-C3N4-PS system exhibits an efficient activity for PS activation and a high efficiency for pollutant degradation. The results show that 100 mL of a 5 mg/L AAP solution could be almost completely degraded in 30 min with 0.5 g/L photocatalyst and 2 mM PS, and TOC can be decreased by 82.5% in 60 min. After adding PS, the degradation rate of the TiO2/g-C3N4 photocatalytic system was greatly improved by nearly 13 times, compared to the TiO2/g-C3N4 system. The radical quenching experiments and electron paramagnetic resonance (EPR) results indicate that SO4−, OH and h+ all contribute to eliminating organic compounds. Additionally, the TiO2/g-C3N4-PS photocatalytic system was employed to eliminate other typical micropollutants, such as phenol, bisphenol A and carbamazepine, and experiments were also carried out using real water matrices, and the ideal performance shows that the TiO2/g-C3N4-PS photocatalytic system has a strong nonselective oxidative ability for degrading contaminants.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A single device combining the functions of a CO2 electrolyzer and a formate fuel cell is a new option for carbon‐neutral energy storage but entails rapid, reversible and stable interconversion ...between CO2 and formate over a single catalyst electrode. We report a new catalyst with such functionalities based on a Pb–Pd alloy system that reversibly restructures its phase, composition, and morphology and thus alters its catalytic properties under controlled electrochemical conditions. Under cathodic conditions, the catalyst is relatively Pb‐rich and is active for CO2‐to‐formate conversion over a wide potential range; under anodic conditions, it becomes relatively Pd‐rich and gains stable catalytic activity for formate‐to‐CO2 conversion. The bifunctional activity and superior durability of our Pb–Pd catalyst leads to the first proof‐of‐concept demonstration of an electrochemical cell that can switch between the CO2 electrolyzer/formate fuel cell modes and can stably operate for 12 days.
A lead–palladium alloy catalyst that reversibly changes its composition and function under electrochemically reducing versus oxidizing conditions is reported. Its bifunctional activity and superior durability enable a proof‐of‐concept electrochemical device integrating the functions of a carbon dioxide electrolyzer and a formate fuel cell.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
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•Non-proportional loading paths imposed on nickel-based superalloy using crystal plasticity.•Potential mechanistic explanation for non-proportional detrimental effects in fatigue ...proposed.•Non-proportionality giving more slip activations, driving up GND and leading to shorter lives.
A dislocation and gradient-based crystal plasticity finite element study of fatigue has been carried out for nickel-based superalloy RR1000 in order to investigate detrimental non-proportional effects on fatigue life. Six differing multiaxial loading cycles including both proportional and non-proportional paths have been addressed and a critical stored energy density criterion employed for fatigue life. Non-proportional paths are shown to lead to higher numbers of intragranular slip system activations, reflecting experimental observations. These give higher geometrically necessary dislocation (GND) densities resulting from slip system interaction occurring through latent hardening effects in the model. The higher GND densities in turn drive up local stress and stored energy densities, thereby leading to lower predicted fatigue lives, in keeping with non-proportional fatigue experiments in the alloy considered. Intragranular slip system interaction may be the mechanistic explanation for non-proportional effects in fatigue of engineering alloys.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this paper, a Gaussian mixture network distribution finance has been carried out to assess the risk, which is used as a risk assessment tool for the visual platform of higher vocational financial ...education. Financial data is quantified and determined by determining the cumulative expected loss amount to establish the financial investment risk assessment function. The Activiti open-source workflow engine was utilized to remove complex financial data and configure the K-line as the platform’s data visualization tool. Finally, the financial education visualization platform was used to analyze the Gaussian distribution and K-line data of X stock, which verified the practicality of the platform, and the effectiveness of the platform was verified by taking the students of H higher vocational college as the sample of the teaching experiment. The results show that the influence coefficient of the platform teaching on the quality of the course is 0.856, and the influence coefficient on the learning interest is 0.887, which indicates that the visual platform teaching makes students interested and strengthens their cognitive level. The visual digital reform of teaching finance majors in colleges and universities is provided with a new reference direction by this paper.
Menthae Haplocalycis herba, one kind of Chinese edible herbs, has been widely utilized for the clinical use in China for thousands of years. Over the last decades, studies on chemical constituents of ...Menthae Haplocalycis herba have been widely performed. However, less attention has been paid to non-volatile components which are also responsible for its medical efficacy than the volatile constituents. Therefore, a rapid and sensitive method was developed for the comprehensive identification of the non-volatile constituents in Menthae Haplocalycis herba using ultra-high performance liquid chromatography coupled with linear ion trap-Orbitrap mass spectrometry (UHPLC-LTQ-Orbitrap). Separation was performed with Acquity UPLC
BEH C
column (2.1 mm × 100 mm, 1.7 μm) with 0.2% formic acid aqueous solution and acetonitrile as the mobile phase under gradient conditions. Based on the accurate mass measurement (<5 ppm), MS/MS fragmentation patterns and different chromatographic behaviors, a total of 64 compounds were unambiguously or tentatively characterized, including 30 flavonoids, 20 phenolic acids, 12 terpenoids and two phenylpropanoids. Finally, target isolation of three compounds named Acacetin, Rosmarinic acid and Clemastanin A (first isolated from Menthae Haplocalycis herba) were performed based on the obtained results, which further confirmed the deduction of fragmentation patterns and identified the compounds profile in Menthae Haplocalycis herba. Our research firstly systematically elucidated the non-volatile components of Menthae Haplocalycis herba, which laid the foundation for further pharmacological and metabolic studies. Meanwhile, our established method was useful and efficient to screen and identify targeted constituents from traditional Chinese medicine extracts.
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