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The electrocatalysts of heteroatom-doped non-precious metal oxide materials are of great significance for efficient and low-cost electrochemical water-splitting systems. Herein, an innovative Fe-doped Co3O4 nanoflake (Fe-Co3O4/NF) on nickel foam has been developed, which exhibits excellent electrocatalytic activity for both hydrogen evolution reactions (HERs) and oxygen evolution reactions (OERs). Benefiting from the synergy of the charge redistribution and d-band center shift caused by doping engineering, the as-obtained Fe-Co3O4/NF shows both excellent HER (η10 = 196 mV) and OER (η10 = 290 mV) activities with low Tafel slopes (109 mV dec−1 for HER and 49 mV dec−1 for OER, respectively) and excellent stability. This work provides an effective method for designing and synthesizing bifunctional electrocatalysts with high activity and stability of metal oxide hybrids for the HER/OER.

High-resolution microdisplay driver applications impose stringent requirements on the static linearity and dynamic performance of digital-to-analog converters (DACs). To meet these requirements, this paper presents a 200 MS/s 12-bit current-steering DAC. To reduce mismatches among high-weight current sources, a split–sort–symmetric grouping calibration (SSSGC) scheme is introduced, in which each most-significant-bit (MSB) current source is split into sub-cells and reorganized through sorting and symmetric pairing. This approach improves static linearity without complex current measurement or compensation loops. Additionally, a group-domain dynamic element matching (DEM) technique is employed to randomize current-source selection and suppress harmonic distortion. Designed in a 0.18 μm BCD process, the proposed DAC achieves an integral nonlinearity (INL) of 0.79 LSB, a differential nonlinearity (DNL) of 0.42 LSB, and a spurious-free dynamic range (SFDR) of 74.9 dB at an output signal of 4.05 MHz.

The electrocatalysts of heteroatom-doped non-precious metal oxide materials are of great significance for efficient and low-cost electrochemical water-splitting systems. Herein, an innovative Fe-doped Co[sub.3]O[sub.4] nanoflake (Fe-Co[sub.3]O[sub.4]/NF) on nickel foam has been developed, which exhibits excellent electrocatalytic activity for both hydrogen evolution reactions (HERs) and oxygen evolution reactions (OERs). Benefiting from the synergy of the charge redistribution and d-band center shift caused by doping engineering, the as-obtained Fe-Co[sub.3]O[sub.4]/NF shows both excellent HER (η [sub.10] = 196 mV) and OER (η [sub.10] = 290 mV) activities with low Tafel slopes (109 mV dec[sup.−1] for HER and 49 mV dec[sup.−1] for OER, respectively) and excellent stability. This work provides an effective method for designing and synthesizing bifunctional electrocatalysts with high activity and stability of metal oxide hybrids for the HER/OER.

Experimental flow stress–strain data under different stress states are often used to calibrate the plastic constitutive model of anisotropic metal materials or identify the appropriate model that is able to reproduce their plastic deformation behavior. Since the experimental stress–strain data are discrete, they need to be mathematically returned to a continuous function to be used to describe an equivalent hardening increment. However, the regression results obtained using existing regression models are not always accurate, especially for stress–strain curves under biaxial stress loading conditions. Therefore, a new regression model is proposed in this paper. The highest-order term in the recommended form of the new model is quadratic, so the functional relationships between stress–strain components can be organized into explicit expressions. All the experimental data of the uniform deformation stage can be substituted into the new model to reasonably reproduce the biaxial experimental stress–strain data. The regression results of experimental data show that the regression accuracy of the new model is greatly improved, and the residual square sum SSE of the regression curves of the new model reduced to less than 50% of the existing three models. The regression results of stress–strain curves show significant differences in describing the yield and plastic flow characteristics of anisotropic metal materials, indicating that accurate regression results are crucial for accurately describing the anisotropic yielding and plastic flow behaviors of anisotropic metal materials.

The electrocatalysts of heteroatom-doped non-precious metal oxide materials are of great significance for efficient and low-cost electrochemical water-splitting systems. Herein, an innovative Fe-doped Co O nanoflake (Fe-Co O /NF) on nickel foam has been developed, which exhibits excellent electrocatalytic activity for both hydrogen evolution reactions (HERs) and oxygen evolution reactions (OERs). Benefiting from the synergy of the charge redistribution and d-band center shift caused by doping engineering, the as-obtained Fe-Co O /NF shows both excellent HER ( = 196 mV) and OER ( = 290 mV) activities with low Tafel slopes (109 mV dec for HER and 49 mV dec for OER, respectively) and excellent stability. This work provides an effective method for designing and synthesizing bifunctional electrocatalysts with high activity and stability of metal oxide hybrids for the HER/OER.

We propose an experimental method to identify anisotropic coefficients in non-principal axis directions of thin-walled tubes. The method involves extracting specimens from the parent tubes and machining a hole in the axial center. The specimens are then inserted into a tube without a hole. The inner diameter of the specimen is theoretically equal to the outer diameter of the inner tube. The double-layer tube undergoes free bulging under internal pressure in our self-developed experimental equipment, with the hole on the specimen expanding simultaneously. The stress states around the hole are uniaxial, and the hole deformation can reflect the anisotropic plastic flow characteristics of the tube. Furthermore, based on the information obtained from the proposed experimental method, a hybrid numerical–experimental method was used to identify the anisotropic coefficients of tubes. Through FE simulations, the relationships between the thickness, stress, and strain states around the hole, the hole shape, and anisotropic coefficients of non-principal axis directions are revealed, and the factors that affect the hole deformation are analyzed. Finally, the hole bulging experiments and FE simulations of AA6061-O extruded tube were conducted, and modeled with Hill48 and calibrated by uniaxial tensile and hoop tensile tests. Its in-plane anisotropy coefficients in any direction are given for the first time which first increase and then decrease from 0° to 90°, reaching a maximum of 1.13 in 60° and a minimum of 0.69 in 0°. This work can provide the key experimental data for establishing an accurate anisotropic plastic constitutive model of thin-walled tubes.

This work provided an efficient alternative strategy to improve the performance of AVO 4 (A = Bi, Fe)-based materials for organic degradations under visible light. Carbon nanofibers (CNFs) as a flexible template were obtained by an electrospinning technique, then AVO 4 as the primary visible light-absorbers were succesfully grown on the surface of template frameworks for producing AVO 4 /CNFs heterostructures via a hydrothermal method. Photocatalytic studies revealed removal efficiencies were greatly increased when CNFs were introduced into AVO 4 heterostructures, compared with pure BiVO 4 and FeVO 4 , with 94 and 90.6% of RB photocatalytically degraded by BiVO 4 /CNFs and FeVO 4 /CNFs heterostructures within 3 h under visible light irradiation. The enhanced photocatalytic activity might have arisen from the high separation efficiency of photogenerated electron–hole pairs based on positive synergetic effects between AVO 4 and CNFs heterojunctions. These heterostructures were easily recycled without a decrease in photocatalytic activity benefited from the nanofibers frameworks. Moreover, this paper confirmed a simple and a general method for fabricating other VO 4 -containing oxides heterostructures.

While inheriting the exceptional merits of single atom catalysts, diatomic site catalysts (DASCs) utilize two adjacent atomic metal species for their complementary functionalities and synergistic actions. Herein, a DASC consisting of nickel-iron hetero-diatomic pairs anchored on nitrogen-doped graphene is synthesized. It exhibits extraordinary electrocatalytic activities and stability for both CO 2 reduction reaction (CO 2 RR) and oxygen evolution reaction (OER). Furthermore, the rechargeable Zn-CO 2 battery equipped with such bifunctional catalyst shows high Faradaic efficiency and outstanding rechargeability. The in-depth experimental and theoretical analyses reveal the orbital coupling between the catalytic iron center and the adjacent nickel atom, which leads to alteration in orbital energy level, unique electronic states, higher oxidation state of iron, and weakened binding strength to the reaction intermediates, thus boosted CO 2 RR and OER performance. This work provides critical insights to rational design, working mechanism, and application of hetero-DASCs. Diatomic site catalysts utilize two adjacent atomic metal species for their complementary functionalities and synergistic actions. Here, the authors report the orbital coupling of hetero-diatomic nickel-iron site boosts CO 2 reduction reaction and oxygen evolution reaction.

Photocatalytic two-electron oxygen reduction to produce high-value hydrogen peroxide (H 2 O 2 ) is gaining popularity as a promising avenue of research. However, structural evolution mechanisms of catalytically active sites in the entire photosynthetic H 2 O 2 system remains unclear and seriously hinders the development of highly-active and stable H 2 O 2 photocatalysts. Herein, we report a high-loading Ni single-atom photocatalyst for efficient H 2 O 2 synthesis in pure water, achieving an apparent quantum yield of 10.9% at 420 nm and a solar-to-chemical conversion efficiency of 0.82%. Importantly, using in situ synchrotron X-ray absorption spectroscopy and Raman spectroscopy we directly observe that initial Ni-N 3 sites dynamically transform into high-valent O 1 -Ni-N 2 sites after O 2 adsorption and further evolve to form a key *OOH intermediate before finally forming HOO-Ni-N 2 . Theoretical calculations and experiments further reveal that the evolution of the active sites structure reduces the formation energy barrier of *OOH and suppresses the O=O bond dissociation, leading to improved H 2 O 2 production activity and selectivity. Here, the authors explore how Ni single-atom sites on carbon nitride evolve under photocatalytic conditions. They show that this evolution plays a pivotal role in enhancing photocatalytic H 2 O 2 production.

Wavelength modulation spectroscopy (WMS) is a representative implementation of tunable diode laser absorption spectroscopy (TDLAS), enabling reliable gas component analysis with concentration-related information derived from harmonic component extraction, while offering enhanced noise immunity for trace gas sensing in open environments. However, due to the strong coupling between laser wavelength and intensity, wavelength modulation inevitably introduces residual amplitude modulation (RAM), which significantly degrades measurement accuracy. To address this issue, this study introduces a RAM suppression algorithm based on multiple harmonic component decoupling (MHCD), using the second-harmonic lateral peak inclination angle (LPIA) as a characteristic indicator. Unit harmonic operators for the first, second, and third harmonics are designed, and an original harmonic reconstruction model is established via linear superposition of harmonic components. The optimal harmonic component ratio is determined at the composite operator with the maximum cross-correlation coefficient, and RAM noise is eliminated through a multi-harmonic decoupling matrix. Repetitive measurements on 22 mm pharmaceutical vials with 4% oxygen concentration demonstrate that MHCD reduces the second-harmonic LPIA from 18.07° to 8.56°. Concentration discrimination experiments conducted on seven groups of 22 mm vials with 2% concentration steps (0–12%) show that MHCD increases the true positive rate by 6–11% and decreases the false positive rate by 4–9%, confirming its effectiveness for pharmaceutical online inspection applications.