The development of bifunctional electrocatalysts with high performance for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) with earth-abundant elements is still a challenge ...in electrochemical water splitting technology. Herein, we fabricated a free-standing electrocatalyst in the form of vertically oriented Fe-doped Ni3S2 nanosheet array grown on three-dimensional (3D) Ni foam (Fe-Ni3S2/NF), which presented a high activity and durability for both HER and OER in alkaline media. On the basis of systematic experiments and calculation, the Fe-doping was evidenced to increase the electrochemical surface area, improve the water adsorption ability, and optimize the hydrogen adsorption energy of Ni3S2, which resulted in the enhancement of HER activity on Fe-Ni3S2/NF. Moreover, metal sites of Fe-Ni3S2/NF were proved to play a significant role in the HER process. During the catalysis of OER, the formation of Ni–Fe (oxy)hydroxide was observed on the near-surface section of Fe-Ni3S2/NF, and the introduction of the Fe element dramatically enhanced the OER activity of Ni3S2. The overall water splitting electrolyzer assembled by Fe-Ni3S2/NF exhibited a low cell voltage (1.54 V @ 10 mA cm–2) and a high durability in 1 M KOH. This work demonstrated a promising bifunctional electrocatalyst for water electrolysis in alkaline media with potential application in the future.
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bstract
The theoretical framework of the neutrino electron excitation at low energies including the screening effect in semiconductor detectors is developed for the first time, both in the Standard ...Model of particle physics and in the presence of the neutrino magnetic moment. We apply the framework of the non-relativistic effective theory on the neutrino electron scattering and explore the contribution of the screening effect of semiconductors to the neutrino electron excitation based on the linear response theory. We calculate the corresponding numerical results with the popular silicon and germanium targets and show that excitation rates from the neutrino magnetic moment are dramatically enhanced by the screening effect and the sensitivity can be significantly improved to the level of 10
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, much better than the current best limits from the laboratory and astrophysical probes.
•The calculation model of segment rebar corrosion is established.•The upper track bed structure is contained in the calculation model.•The full-scale test of segment is designed and compared with ...calculation.•Effect of DC stray current on rebar corrosion in cracked segment was investigated.
The calculation model of segment rebar corrosion is formulated to study the rebar corrosion induced by stray direct current in the cracked segment of a shield tunnel. The model includes the upper track bed structure because the concrete in this structure has electrical resistance and affects the stray current distribution. To verify the accuracy of the calculation model, a full-scale test of the shield segment is designed. The potential distribution and rebar corrosion law in the cracked segment under different input and output positions are separately investigated through calculations. The result shows that the rebar corrosion rate in the segment is related to the input mode and the distance of the rebar corrosion from the current input location. When the stray current output locations remain unchanged, the maximum current density in the rebar under bilateral leakage is approximately two to three times that under unilateral leakage. Increasing the stray current in the output sides reduces the maximum current density in the segment rebar. When the output edge contains multiple-segment cracks, the closer the current output position to the middle of the segment in the circumferential direction, the larger the current density.
Dark matter (DM) direct detection experiments are entering the multiple-ton era and will be sensitive to the coherent elastic neutrino nucleus scattering (CEνNS) of solar neutrinos, enabling the ...possibility to explore contributions from new physics with light mediators at the low energy range. In this paper we consider light mediator models (scalar, vector and axial vector) and the corresponding contributions to the solar neutrino CEνNS process. Motivated by the current status of new generation of DM direct detection experiments and the future plan, we study the sensitivity of light mediators in DM direct detection experiments of different nuclear targets and detector techniques. The constraints from the latest 8B solar neutrino measurements of XENON-1T are also derived. Finally, we show that the solar neutrino CEνNS process can provide stringent limitation on the Lμ−Lτ model with the vector mediator mass below 100 MeV, covering the viable parameter space of the solution to the (g−2)μ anomaly.
We study the radiative decay of X(3872) based on the assumption that X(3872) is regarded as a cc‾ charmonium with quantum number JPC=1++ (J,P,C represent the spin, parity and charge conjugation, ...respectively). The form factors of X(3872) transitions to J/ψγ and ψ′γ (ψ′ denotes ψ(2S) throughout the paper) are calculated in the framework of the covariant light-front quark model. The phenomenological wave function of a meson depends on the parameter β, whose inverse essentially describes the confinement scale. In the present work, the parameters β for the vector J/ψ and ψ′ mesons will be determined through their decay constants, which are obtained from the experimental values of their partial decay widths to the electron-positron pair. For X(3872), we determined the value of β by the decay width of X(3872)→ψ′γ. Then, we examined the width of X(3872)→J/ψγ in a manner of parameter-free prediction and compared it with the experimental value. As a result, an inconsistency or contradiction occurs between the widths of X(3872)→J/ψγ and X(3872)→ψ′γ. We thus conclude that X(3872) cannot be a pure cc‾ resonance and that other components are necessary in its wave function.
Twin-field quantum key distribution can overcome the secret key capacity of repeaterless quantum key distribution via single-photon interference. However, to compensate for the channel fluctuations ...and lock the laser fluctuations, the techniques of phase tracking and phase locking are indispensable in experiment, which drastically increase experimental complexity and hinder free-space realization. We herein present an asynchronous measurement-device-independent quantum key distribution protocol that can surpass the secret key capacity even without phase tracking and phase locking. Leveraging the concept of time multiplexing, asynchronous two-photon Bell-state measurement is realized by postmatching two interference detection events. For a 1 GHz system, the new protocol reaches a transmission distance of 450 km without phase tracking. After further removing phase locking, our protocol is still capable of breaking the capacity at 270 km. Intriguingly, when using the same experimental techniques, our protocol has a higher key rate than the phase-matching-type twin-field protocol. In the presence of imperfect intensity modulation, it also has a significant advantage in terms of the transmission distance over the sending-or-not-sending-type twin-field protocol. With high key rates and accessible technology, our work provides a promising candidate for practical scalable quantum communication networks.
Phosphoenolpyruvate carboxykinase (PCK) has been almost exclusively recognized as a critical enzyme in gluconeogenesis, especially in the liver and kidney. Accumulating evidence has shown that the ...enhanced activity of PCK leads to increased glucose output and exacerbation of diabetes, whereas the defects of PCK result in lethal hypoglycemia. Genetic mutations or polymorphisms are reported to be related to the onset and progression of diabetes in humans.
Recent studies revealed that the PCK pathway is more complex than just gluconeogenesis, depending on the health or disease condition. Dysregulation of PCK may contribute to the development of obesity, cardiac hypertrophy, stroke, and cancer. Moreover, a regulatory network with multiple layers, from epigenetic regulation, transcription regulation, to posttranscription regulation, precisely tunes the expression of PCK. Deciphering the molecular basis that regulates PCK may pave the way for developing practical strategies to treat metabolic dysfunction.
In this review, we summarize the metabolic and non-metabolic roles of the PCK enzyme in cells, especially beyond gluconeogenesis. We highlight the distinct functions of PCK isoforms (PCK1 and PCK2), depict a detailed network regulating PCK's expression, and discuss its clinical relevance. We also discuss the therapeutic potential targeting PCK and the future direction that is highly in need to better understand PCK-mediated signaling under diverse conditions.
Over half of older patients with acute myeloid leukemia (AML) do not respond to cytotoxic chemotherapy, and most responders relapse because of drug resistance. Cytarabine is the main drug used for ...the treatment of AML. Intensive treatment with high-dose cytarabine can increase the overall survival rate and reduce the relapse rate, but it also increases the likelihood of drug-related side effects. To optimize cytarabine treatment, understanding the mechanism underlying cytarabine resistance in leukemia is necessary. In this study, the gene expression profiles of parental HL60 cells and cytarabine-resistant HL60 (R-HL60) cells were compared through gene expression arrays. Then, the differential gene expression between parental HL60 and R-HL60 cells was measured using KEGG software. The expression of numerous genes associated with the nuclear factor κB (NF-κB) signaling pathway changed during the development of cytarabine resistance. Proteasome inhibitors inhibited the activity of non-canonical NF-κB signaling pathway and induced the apoptosis of R-HL60 cells. The study results support the application and possible mechanism of proteasome inhibitors in patients with relapsed or refractory leukemia.
In this work, we introduce the theoretical framework of the phonon-mediated Migdal effect for neutrino-nucleus scattering in semiconductors, considering both the Standard Model and the presence of ...the neutrino magnetic moment. We calculate the rate of electron excitation resulting from the Migdal effect and observe a substantial coherent enhancement compared to ordinary neutrino-electron scattering. Furthermore, we provide numerical sensitivities for detecting the Migdal effect and constraints on the neutrino magnetic moment, utilizing an experimental setup with reactor neutrinos.
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