Solid-liquid gating is a promising route to probe the electrostatics of two-dimensional semiconductors, yet its mechanisms are easily obscured by interface defects and discharge paths introduced by ionic double layers in conventional measurement circuits. We address these issues with two advances: (i) a damage-free all-solid-liquid contact that suppresses interface degradation and trapping, and (ii) a measurement architecture that isolates the ionic-liquid (IL) double layer from circuit discharge, employing an ultrahigh-input-impedance follower to read the gate potential in operando. These measures deliver accurate and highly reproducible gate potentials. With this direct potential metrology, we measured the IL potential at the mid-channel, providing a more direct basis for explaining the apparent long-channel pinch-off effect. Crucially, we find that threshold voltage shifts correlate with the gate metals' intrinsic open-circuit potentials, not their work-function differences, overturning a common assumption. Together, these results clarify the mechanism of solid-liquid gating and establish a reliable foundation for designing low-power, solution-gated nanoelectronics.

Solid-liquid gating is a promising route to probe the electrostatics of two-dimensional semiconductors, yet its mechanisms are easily obscured by interface defects and discharge paths introduced by ionic double layers in conventional measurement circuits. We address these issues with two advances: (i) a damage-free all-solid-liquid contact that suppresses interface degradation and trapping, and (ii) a measurement architecture that isolates the ionic-liquid (IL) double layer from circuit discharge, employing an ultrahigh-input-impedance follower to read the gate potential in operando. These measures deliver accurate and highly reproducible gate potentials. With this direct potential metrology, we measured the IL potential at the mid-channel, providing a more direct basis for explaining the apparent long-channel pinch-off effect. Crucially, we find that threshold voltage shifts correlate with the gate metals' intrinsic open-circuit potentials, not their work-function differences, overturning a common assumption. Together, these results clarify the mechanism of solid-liquid gating and establish a reliable foundation for designing low-power, solution-gated nanoelectronics.

Because of fusion modeling, conventional finite element models face two challenges in viscoelastic analysis: limited flexibility in modifying constitutive models and low computational efficiency. To address these shortcomings, an efficient viscoelastic beam model was developed by separating the constant stiffness matrix and equivalent integral displacement based on the integral form of the constitutive equation. It applies to various materials by freely switching the relaxation modulus function and avoids dynamically updating and reassembling stiffness matrices. Furthermore, the beam model was applied to discretize the cage of rolling bearings, where beam nodes were treated as tiny mass blocks, and their motions were solved using the Newmark-beta method. The influence of viscoelasticity on the dynamic responses of the flexible cage was analyzed. The results indicate that the viscous internal force generated by accumulating the strain history usually opposes the direction of the elastic restoring force, enhancing the external load. Thus, the normal and shear stresses on the dangerous cross-section of the cage calculated by the viscoelastic beam model are greater than those by the elastic beam model. As temperature increases, the viscous internal force grows, causing the stress ratios to deviate gradually from-1, and promoting fatigue cracks. However, the elastic beam model demonstrates an opposite trend, which may cause risks in the safety margin design. Additionally, viscoelasticity exhibits behavior closer to a rigid state, intensifying collisions with rollers. Overall, the viscoelastic beam model provides more accurate guidance for the structural optimization and surface strengthening of the cage to prevent fatigue cracks.

Understanding how core-shell abrasive architecture governs interfacial interactions is critical for balancing material removal rate (MRR) and surface quality in chemical mechanical polishing (CMP). Here, a core-shell abrasive system with a SiO2 core and an organic shell is investigated through an integrated approach combining polishing experiments, physicochemical characterization, and multiscale molecular dynamics (MD) simulations. Polishing experiments on single-crystal silicon demonstrate that a thin organic shell significantly improves surface quality while reducing MRR, suggesting that the organic shell suppresses aggressive mechanical interaction at the abrasive-substrate interface. MD simulations reveal a non-monotonic dependence of particle-substrate adhesion on shell thickness. A single organic layer markedly enhances adhesion by positioning interfacial atoms within the energetically favorable van der Waals interaction distance, whereas further shell thickening reduces adhesion due to increased interfacial separation and electrostatic screening. Atomic force microscopy (AFM) measurements provide experimental evidence for the enhanced adhesion in the thin-shell regime. Reactive MD (RMD) simulations further show that the organic shell acts as a compliant buffer that redistributes contact stress, mitigates localized deformation, and significantly reduces defect generation, promoting a transition from defect-dominated removal to a more uniform and controlled process. The experimentally observed shell thickness (approximately 1.38 nm) coincides with the regime where adhesion enhancement and mechanical compliance are optimally coupled. These findings reveal the structure-property relationship governing polishing behavior and provide rational design principles for high-performance core-shell abrasives.

Abstract As semiconductor manufacturing advances toward three-dimensional (3D) integration architectures, the precise chemical mechanical polishing (CMP) of high-aspect-ratio (HAR) nanothrough-silicon vias (n-TSVs) utilizing cobalt (Co) interconnects has become critically important. However, achieving nanoscale, nondestructive, and accurate evaluation of Co core exposure and interfacial planarization during the CMP process remains a formidable metrological challenge. Herein, we report the reliable nanoscale compositional characterization of SiO2/TiN/Co n-TSV heterostructures across progressive CMP stages using a custom-built 405 nm photoinduced force microscopy (PiFM) system capable of simultaneously acquiring optical force amplitude and phase signals. By leveraging both amplitude and phase mapping, together with material-dependent variations in the relative contributions of repulsive photothermal expansion forces and attractive optical gradient forces, PiFM precisely tracks the nanoscale structural evolution of n-TSVs during CMP–specifically, the progressive removal of overlayers and the eventual unmasking of the Co core. Notably, we demonstrate that the optical force phase signal provides clearer material contrast and improved detection sensitivity compared to conventional optical force amplitude imaging. This phase-sensitive contrast enables reliable differentiation of complex heterogeneous interfaces and tracks localized Co core exposure, as well as subsequent material depletion due to overpolishing. Finally, correlative conductive atomic force microscopy validates the polishing progression and Co exposure logic inferred by PiFM. This work establishes 405 nm PiFM as a promising, facile, and nondestructive metrology tool. By leveraging both optical force amplitude and phase signals, it provides critical feedback for characterizing nanoscale material interfaces and evaluating polishing quality in Co-based n-TSV interconnects, thereby facilitating CMP process optimization and improving the reliability of next-generation 3D interconnect architectures.

The process of elimination at the atomic level stands as the paramount step in crafting ultra-smooth gallium nitride (GaN) substrates. However, this delicate removal mechanism presents a notable challenge. In this study, we employed a scraping technique utilizing atomic force microscope (AFM) probe manipulation to conduct an in-situ examination of atomic-scale removal behaviors. Through in-situ regular imaging, we uncovered the principles underlying atomic-scale removal. We systematically explored how scraping and imaging techniques impacted surface topography and the behavior of atomic step-terraces removal. Our findings indicated that abrasives knocking facilitates the emergence of atomic step-terraces, while sliding removal techniques hinder the structure. During the scraping process, both the upper and lower sections of the atomic step-terraces were simultaneously eliminated, with material removal rate (MRR) being slower at the bottom. To validate our in-situ observations, we conducted polishing experiments. Furthermore, the coefficient of friction (COF) recorded during chemical mechanical polishing offered insights into the frictional disparities of abrasives on the GaN surface, thereby shedding light on the atomic-scale removal mechanism.

The upgrading of underutilized methane in shale gas with anthropogenic CO2 can produce the value-added syngas via dry reforming. Nickel-based catalysts, due to their efficiency and cost-effectiveness, have received widespread attention. However, Ni-catalyzed dry reforming of methane is usually subjected to sintering or coking-induced instability. To address these issues, a series of Al2O3-supported nickel nanoparticle catalysts with uniform sizes are synthesized by varying the calcination temperatures and applied in methane dry reforming (DRM). Ni/Al2O3-700 °C catalyst behaves better catalytic performance compared to the other catalysts, which can be attributed to its higher metal dispersion and stronger metal-support interaction. In addition, the abundant moderate-strength basic sites and optimal AlIV/AlVI ratio can promote the adsorption and activation of CO2 and suppress the deep cracking of CH4 for Ni/Al2O3-700 °C catalyst, respectively, causing the enhancement of anti-coking performance. Furthermore, combining CH4-temperature programmed surface reaction and in situ Fourier transform infrared spectroscopy demonstrates that the presence of CO2 can promote the activation of CH4 for Ni/Al2O3-700 °C catalyst, which is rate-determining step for DRM system. These findings provide valuable theoretical guidance for the rational design of Ni-based catalysts with enhanced catalytic performance.

In practice, the bending moment for bearings is inevitable and affects the contact and power loss characteristics. However, research comprehensively analyzing the effect of bending moment on cylindrical roller bearings (CRB) is rarely reported. To address this research gap, this study improves the quasi-dynamic model of CRBs in three aspects and analyzes the effect of the bending moment, bearing clearance, and roughness on the contact, slip, and power loss characteristics based on it. The improved model can adaptively identify the azimuth of contact points based on the tangent plane vector, which corrects the wrong approach relation between non-overlapping surface curvatures caused by the traditional fixed point assumption under askew contact; a compatibility equation is proposed between the relative position of contact points, deformation, and oil film thickness to couple lubrication during calculating contact load; adding the artificial viscosity to the difference scheme representing the inertia term of rollers solves the numerical oscillation of speed caused by the shock wave. The improved model is confirmed experimentally. The simulation results show as the bending moment increases, the contact region between rollers and raceways decreases, and the contact pressure and von Mises stress increase, thereby reducing the slip rate. Reduced contact region means reducing power losses caused by contact. The bearing clearance has similar effects. To reduce power losses, the bending moment and bearing clearance should be appropriately increased. The research results can effectively guide the optimization design of CRBs.

The crystal planes tailored lattice oxygen mechanism for the competitive and promising process of directly synthesizing dimethyl carbonate (DMC) from carbon dioxide (CO2) and methanol have been comprehensively investigated. Steady-state in-situ micro-reaction Fourier transform infrared spectroscopy (FTIR) combined with density functional theory (DFT) calculations were conducted on a series of CeO2 model catalysts to elucidate the formation pathway of DMC. The previously theoretically predicted methoxycarbonyl (MC, CH3OCO*) intermediate was experimentally identified through FTIR spectroscopy. Only on the active (110) surface do lattice oxygen and Ov participate in the reaction cycle, facilitating critical reaction steps and shifting the reaction pathway from the electrophilic addition of methyl species to monomethyl carbonate (MMC, CH3OCOO*) on the (111) surface to the nucleophilic addition of methoxy species to MC. The established structure-activity relation holds a promise for providing effective guidance in CeO2-based catalyst design at a mechanistic level.

Contact engineering at the semiconductor–electrode and semiconductor–dielectric interfaces is critical to the performance of electronic devices, especially for delicate 2D semiconductors. Here, this study proposes a new paradigm of flexible field‐effect transistors featuring solid–liquid hybrid interfaces, in which liquid metal and ionic liquid, confined within microchannels, function as the source/drain electrodes and gate dielectric, respectively. These interfaces provide MoS₂ with undisturbed, atomically smooth electrical contacts, and enable efficient gate control via electric double layers. Benefiting from the inherent softness of liquids and their damage‐free processing, Fermi level pinning is significantly mitigated by the liquid metal, achieving a pinning factor |s| = 0.7. Meanwhile, the ionic liquid enables a subthreshold swing of 60.7 mV dec −1 , approaching the theoretical thermal limit. Furthermore, our flexible transistors demonstrate multifunctionality as enhanced logic gates, low‐voltage inverters, and ultra‐high‐linearity synaptic devices. This work underscores the promise of liquid‐enabled contact strategies for advancing low‐power, flexible electronics and soft robotic systems.

Existing dynamic models of the crank-connecting rod mechanism (CRM) primarily focus on single clearance lubrication in piston engines, making it difficult to analyze the coupled effects of crankshaft misalignment and mixed lubrication of bearings under multi-clearance collaboration. This study proposes a novel dynamic model that integrates multi-clearance lubrication. Based on the generalized coordinates of the crank and connecting rod, including misalignment angles in two directions, the dynamic boundary conditions of the three-dimensional lubrication fields of the big-end and main bearings are calculated synchronously, and incorporated into a mixed elasto-hydrodynamic lubrication (MEHD) model to evaluate the friction performance. The motion equations are derived using the Lagrange method with a variable-step fourth-order Runge-Kutta (VRK4) method to address numerical instability under multi-clearance misalignment. Furthermore, the coupled effects of operating parameters and misalignment on the friction and wear characteristics of the bearings are examined. The results show that crankshaft misalignment significantly increases the volumetric wear rate and friction power loss, with more pronounced effects under low-speed, high-load conditions. Appropriate bearing clearance and lubrication viscosity can help mitigate the adverse effects of misalignment. This study provides a high-precision simulation framework for analyzing and designing piston engine bearings and elucidates the misalignment fault mechanisms.

With the rapid development of two-dimensional (2D) materials and their heterostructures in advanced electronic and optoelectronic applications, there is an increasing need for precise characterization of 2D materials. In this work, we developed multimode visible optical force microscopy (MV OFM) to address this demand, offering a convenient and powerful tool for the nanoscale characterization of 2D materials. The MV OFM utilizes a visible 405 nm semiconductor laser and an oscillator within a lock-in amplifier for analog modulation, simplifying the system by eliminating the need for an expensive laser, a chopper or an acousto-optic modulator (AOM). It operates in three distinct modes, contact, tapping (homodyne), and tapping (heterodyne) mode, enabling precise detection of optical force signals using a silicon tip in the ambient atmosphere. The phase signal allows for qualitative analysis of optical forces, revealing disparities in material properties. The MV OFM can achieve a spatial resolution of similar to 10 nm, offering high sensitivity and contrast by using the optical force phase. By adjusting laser power, setpoint, material thickness, and material type, MV OFM can selectively tune dominant optical forces. Additionally, MV OFM is compatible with the transparent substrate (glass), extending its applicability. With these capabilities, we demonstrated the differentiation of materials components in hexagonal boron nitride/molybdenum disulfide (h-BN/MoS2) heterostructure and the precise characterization of the subsurface boundary, which is crucial for optimizing the performance of two-dimensional materials heterostructures in electronic and optoelectronic applications.

Stiffness is the key dynamic parameter of the angular contact ball bearing. This work established a dynamic bearing model based on Hertz theory and thermo-elastohydrodynamic lubrication (TEHL) and compared the contact angle, inner race position, and stiffness. In most cases, the stiffness calculated via Hertz was higher than when using TEHL. The axial stiffness values determined via the two theories were close, while the radial stiffness calculated via the Hertz theory was smaller than that determined by TEHL under light load and high speed. Considering the elastic deformation of the races and the initial contact angle, the results obtained by TEHL displayed a lower error rate in the experiment than Hertz.

Organic piezoelectric nanogenerators (PENGs) show promise for monitoring damage in mechanical equipment. However, weak interfacial bonding between the reinforcing phase and the fluorinated material limits the feedback signal from the damaged area. In this study, we developed a PENG film capable of real-time identification of the damage location and extent. By incorporating core-shell barium titanate (BTO@PVDF-HFP) nanoparticles, we achieved enhanced piezoelectric characteristics, flexibility, and processability. The composite film exhibited an expanded output voltage range, reaching 41.8 V with an increase in frequency, load, and damage depth. Additionally, the film demonstrated self-powered electroluminescence (EL) during the wear process, thanks to its inherent ferroelectric properties and the presence of luminescent ZnS:Cu particles. Unlike conventional PENG electroluminescent devices, the PENG film exhibited luminescence at the damage location over a wide temperature range. Our findings offer a novel approach for realizing modular and miniaturized real-time damage mapping systems in the field of safety engineering.

Although the strength of conventional polyurethane fibers can be modulated using strain-induced crystallization strategies, current fabrication processes cannot achieve sufficient strength and toughness. Here, we report a novel strategy involving precise adjustment of hydrogen-bond donor unit positions and directed arrangement of the polyurethane backbone to enhance the strength and toughness of a new fiber type (i-PUF). New nanocrystals could be formed continuously in the amorphous phases of the i-PUFs due to strong interchain interactions in response to the increasing strain, causing anomalous strengthening behavior. The tensile strength of the i-PUFs was 1.3 GPa, 3.1 times that of the strongest polyurethane fibers. Moreover, the toughness value of the i-PUFs was 244.8 MJ/m3, 1.4 times higher than that of spider dragline silk. Additionally, the i-PUFs exhibited excellent self-healing properties since the slip effect of the hydrogen bonds in the nanocrystals were enhanced by external thermal stimulation. The proposed approach can be applied to various commercial polymers to fabricate durable polymer fibers with enhanced strength and toughness.

As a crucial part in micro-electromechanical manufacture, local ultra-precision processing of highly ductile copper is expected to be realized by fluid jet polishing (FJP), which widely utilized in optical elements. Since copper exhibits different wear behavior from stiff and brittle material, there is currently no abrasive wear prediction model applicable for copper to investigate the polishing mechanism. This research reveals that the copper material removal is dominated by deformation wear rather than cutting wear through abrasive jet impact experiments and localized wear scars analysis. A three-dimensional gas-liquid-particle triphasic wear model for copper in FJP is developed by considering impact energy and wear mechanism simultaneously. Ultimately, validation assessments at various working pressures and impingement angles achieve the goodness-of-fit up to 0.92–0.97 in quantitative comparison between simulations and experimental measurements, which demonstrate the wear prediction ability of the proposed model. This investigation facilitates a better understanding of copper wear mechanism and provides theoretical guidance for FJP process optimization.

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To improve the stiffness of the bearing-rotor system, angular contact ball bearings are usually matched and mounted on the spindle. However, the flexibility of the shaft could result in an uneven load on the bearings. This paper proposed a bearing-rotor model based on the explicit finite element and dynamic bearing model coupled with thermo-elastohydrodynamic lubrication(TEHL). Reduced integration hexahedral solid element was used to model the flexible rotor. The impacts of load, rotor parameters, and configuration of bearing set on the radial load of the matched bearings have been analyzed. The load difference between the matched bearings decreased by increasing the stiffness of the bearing-rotor system and minimizing the distance between the equivalent bearing positions of the bearing set. Finally, the experimental phenomenon of high-speed matched bearings was explained through simulation analysis.