Search Results (81)

Co-based oxides are commonly introduced into porous ceramic membranes to add catalytic activity, but their attachment at the atomic scale remains unclear. We examined a buried Co₃O₄/Al₂O₃ interface formed by sol–gel deposition and thermal conversion. Site-specific focused-ion-beam (FIB) lift-out, scanning transmission electron microscopy with energy-dispersive X-ray spectroscopy (STEM-EDS), and high-resolution transmission electron microscopy (HRTEM) were used to access and characterize the interface. A Co-rich spinel-type domain with a (111) lattice spacing was observed next to Al₂O₃(012). The observations guided density functional theory (DFT) initial models. After structural relaxation, substrate-O-mediated Co-O contacts emerged from both starting geometries: the O-bridged-start model exhibited eight contacts across four Co sites, whereas the non-bridged-start model developed three contacts around one Co site. Around the Co-O-Al linkages, there is a clear manifertation of the interface polarization and charge redistribution, indicated by charge-density-difference and Bader analyses. In both models, projected density of states (PDOS) showed coupling between Co 3d and O 2p states, while integrated crystal orbital Hamilton population (ICOHP) analysis further indicated that O atoms retained Al-O bonds while forming occupied-state Co-O bonds. These results support a representative, laterally distributed Co-O-Al motif as an atomic-scale pathway for chemically attaching the functional oxide to porous alumina. Full article

In this paper, a pixel architecture that can be re-programmed to favor low noise, high speed, high dynamic range, or other characteristics desired in scientific imaging is proposed. Termed a programmable readout (PRO) pixel, this novel design combines a pinned photodiode, a deep-buried-channel CCD router, and multiple in-pixel amplifiers of different characteristics. By clocking the CCD router with different sequences, photogenerated charge can be steered to an appropriate readout amplifier given the application. The CCD router can be further programmed to store charge from multiple frames. The concept of such a pixel and its operation are described in detail and TCAD simulations aid in this discussion. To demonstrate this concept of programmability, a test chip is made with a CCD router and two in-pixel amplifiers: a floating diffusion amplifier (FDA) for fast readout and high-illumination imaging and a floating gate amplifier (FGA) for a low-noise Skipper-in-CMOS readout for low-light imaging. The test chip contains a 36 × 94 array of 20 µm pixels and contains 9 different pixel variants for experimental analysis. At the end of the paper, preliminary images captured from the different amplifiers are presented which demonstrate the ability to move charge to the selected readout while showcasing the different output characteristics of the two readout amplifiers. Furthermore, the output image from the Skipper-in-CMOS is compared across different numbers of non-destructive samples to demonstrate its noise-reduction capability. Full article

Inverted perovskite solar cells (PSCs), or p-i-n PSCs, have become increasingly attractive for high-performance perovskite photovoltaics owing to their low-temperature processability, reduced hysteresis, flexible-substrate compatibility and suitability for perovskite/silicon tandem architectures. The buried interface is central to charge extraction, energy-level alignment, perovskite crystallization and operational stability, and is therefore a key determinant of device performance. Self-assembled monolayers (SAMs) are molecularly thin and offer negligible parasitic absorption, tunable interfacial energetics, low material loading and high structural designability, making them attractive alternatives to conventional organic Hole Transport Layers and effective hole-selective contacts in inverted PSCs. This review examines molecular design principles and interfacial engineering strategies for SAMs in inverted PSCs, focusing on the phosphonic acid carbazole (PACz) family, substituent and terminal-group engineering, and emerging conjugated backbones. We then summarize how SAMs regulate buried interfaces through energy-level alignment, defect passivation, crystallization control and stability enhancement. We further highlight emerging interface strategies, including co-assembled SAMs, amorphous SAMs, polymerized or crosslinked SAMs and molecular hybrid interfaces, and discuss how data-driven molecular screening may accelerate future SAM discovery. Finally, we discuss outstanding challenges in SAM formation, large-area uniformity, in situ and operando characterization, and data-driven molecular design, and provide perspectives on the use of SAMs in efficient, durable and scalable inverted PSCs. Full article

AISI 316L stainless steel (316L SS) exhibits inadequate corrosion resistance in chloride-containing soils. Fe-based amorphous coatings (Fe-ACs), owing to their high Cr, Mo, and W contents and defect-free amorphous structure, are promising candidates for superior protection. In this work, the corrosion behavior of 316L SS and an Fe-based amorphous coating (Fe-AC) fabricated by high-velocity oxygen-fuel (HVOF) spraying was systematically compared by burial in Daqing saline soil (25% water content) with 0, 1.0, and 2.0 wt.% NaCl for 15–55 days. Corrosion rates were measured via mass loss, and surface morphology, elemental distribution, and phase constitution were characterized using OM, SEM/EDS, and XRD. Electrochemical impedance spectroscopy and potentiodynamic polarization were employed to assess passive-film stability and charge-transfer resistance. The Fe-AC consistently exhibited an extremely low corrosion rate (below 0.01 mm y⁻¹), nearly independent of NaCl concentration and exposure time, with only sporadic rust spots and the formation of a compact Cr/Mo/W-enriched passive film. In contrast, after 55 days in soil containing 2.0 wt.% NaCl, the 316L SS showed a corrosion rate of 0.0562 mm y⁻¹—six times that of the Fe-AC—accompanied by severe pitting (pit depth up to 3.6 mm) and loose corrosion products (γ-FeOOH and α-Fe₂O₃). Electrochemical tests confirmed that the charge-transfer resistance of the Fe-AC under the 0% NaCl condition reached 1.16 × 10⁶ Ω cm² and its breakdown potential exceeded 1.12 V, far outperforming 316L SS (2.30 × 10³ Ω cm² and 0.22 V, respectively). The novelty of this study lies in the systematic evaluation of the buried corrosion performance of HVOF-sprayed Fe-based amorphous coatings versus 316L SS in an actual saline soil and in elucidating the synergistic passivation mechanism of Cr, Mo, and W. This passive film effectively impedes chloride ingress and maintains high impedance over extended periods. Full article

As dynamic random-access memory (DRAM) continues to scale down and achieve higher integration density, the cell layout has transitioned to 6F², resulting in narrower spacing between adjacent word lines (WLs). Consequently, cell-to-cell disturbance has become more severe. In particular, the row-hammer effect (RHE) has emerged as a critical reliability issue that must be mitigated to ensure stable operation in next-generation DRAM devices. In this study, a novel DRAM cell structure is proposed, in which a low-k dielectric material is embedded beneath the storage node (SN) to mitigate the electric field. This structural modification effectively suppresses the RHE compared to the conventional partial-isolation type buried channel array transistor (Pi-BCAT). The feasibility and performance of the proposed structure were verified through 2D Sentaurus technology computer-aided design (TCAD) simulations. The device embedding the low-k dielectric beneath the SN exhibits a mitigation of approximately 20.45% in D0 failure and about 12.12% in D1 failure. This improvement is attributed to the reduced electric field in the region underneath the SN, which suppresses stored charge leakage. These results confirm that the proposed structure not only enhances DRAM reliability in advanced process nodes but also provides an effective design guideline for highly integrated and low-power memory devices. Full article

To meet the requirements of wide-temperature reliability and fast transient response in power management ICs for automotive, aerospace, and industrial applications, this paper presents a fast-response low-dropout regulator (LDO) based on a 0.18 μm high-temperature SOI process. Benefiting from the buried oxide isolation structure of the SOI technology, leakage current and parasitic effects under high-temperature conditions are effectively suppressed. The proposed LDO employs an NMOS power transistor, with an on-chip charge pump used to enhance the gate driving capability. In addition, a triple-loop regulation scheme consisting of a main negative feedback loop, an auxiliary positive feedback loop, and a current-mode feedback loop is adopted to improve transient performance and enhance loop stability. The fabricated chip occupies an area of 2840 μm × 1490 μm and supports an input voltage range of 3–5.5 V and an output voltage range of 1.2–3.3 V. Over a temperature range of −55 °C to 175 °C, the LDO can deliver a maximum load current of 400 mA. At 175 °C, the measured overshoot and undershoot voltages are 64 mV and 94 mV, respectively, with a maximum recovery time of 336 μs. Moreover, the power supply rejection ratio (PSRR) reaches 56.8 dB at 100 Hz. Experimental results demonstrate that the proposed LDO exhibits excellent high-temperature adaptability, strong load-driving capability, and superior transient response performance. Full article

Accurate quantification of glucose is vital for quality control in the food industry. While earth-abundant Cu has emerged as a promising candidate for non-enzymatic electrochemical sensing, conventional electrode fabrication relying on powder coating with polymeric binders inevitably buries active catalytic sites and impedes both electron transfer and mass transport. In this study, a binder-free, self-supporting Cu nanoparticles/Ni foam (Cu NPs/NF) electrode was developed via a facile one-step hydrothermal method. Benefitting from the enhanced charge-transfer efficiency and a substantially enlarged electrochemical active surface area, the Cu NPs/NF-based electrochemical glucose sensor exhibited a wide linear detection range (0.25–3310.52 μM), a high sensitivity of 7000 μA mM⁻¹ cm⁻², a low detection limit of 0.32 μM, and a rapid response time of 3 s. Furthermore, the developed Cu NPs/NF electrode displayed favorable reproducibility, storage stability, and high selectivity against common interferents present in food matrices, demonstrating its reliability for practical applications. The feasibility of the proposed sensor was successfully validated in real beverage samples. Given the simplicity of the one-step hydrothermal synthesis and the portability afforded by the self-supporting electrode architecture, this Cu NPs/NF electrode emerges as a highly attractive candidate for commercial glucose sensors. Beyond glucose, the design strategy can be readily extended to the detection of other electroactive food-quality markers, enabling the broader applicability of this electrode platform in comprehensive food analysis. Full article

Polyethylene terephthalate (PET) is a synthetic polymer that is widely used in the production of textiles, packaging materials, and beverage bottles. However, its high durability and resistance to abiotic degradation result in serious environmental and health problems. PETase is an enzyme that can depolymerize PET into value-added products, thereby providing an environmentally friendly strategy for PET recycling. PETaseSM14 from a marine sponge, Streptomyces sp. SM14, has a high salt tolerance and thermal stability, thus suggesting its potential for PET degradation applications. However, the substrate recognition mechanism of PETase remains unclear because the catalytic residue is buried within residues that form the substrate-binding cleft. To elucidate the molecular mechanism of PETaseSM14, all-atom molecular dynamics simulations were performed at 300, 320, and 340 K. The results revealed that the overall α/β fold remained stable at all temperatures, whereas temperature-dependent local fluctuations and conformational changes were observed in the substrate-binding cleft and N-terminal region. At 300 and 320 K, positional shifts and conformational changes in Tyr88 exposed the catalytic Ser156 to the solvent, thereby forming a potential substrate-binding cleft. In contrast, at 340 K, which is higher than the melting temperature of PETaseSM14, disruption of the charge-relay system of the catalytic triad occurs through conformational changes in His234. Substantial temperature-dependent conformational and positional changes in the N-terminal region of PETaseSM14 were observed at 320 and 340 K. These results provide mechanistic insight into the temperature-dependent active-site rearrangements and offer rational engineering strategies to enhance the efficiency of PETase for PET biodegradation. Full article

This study addresses the major engineering challenges of leaving roadways along the goaf in shallow-buried coal seam tunnels through water-bearing soft rock. It focuses on three core issues: the mechanism of rock mass softening upon water exposure, large-deformation control, and directional pressure relief technology. By integrating laboratory testing, theoretical analysis, numerical simulation, and field testing methods, the evolution of macro- and micro-mechanical properties of rock under water–rock interaction can be studied. The research developed constant-resistance large-deformation rock bolts with “yielding within resistance and resisting within yielding” characteristics, revealed the mechanism of directional fracturing through shaped charge blasting, and proposed a synergistic control technology for along-the-goal rib retention: “shaped charge blasting for roof fracturing and pressure relief + reinforced rib support + debris retention devices.” Research findings indicate: increased sandstone water content triggers dissolution of calcareous cement and expansion of clay minerals, leading to rock strength degradation and accelerated deformation, yet the failure mode remains uniaxial shear failure. The developed constant-resistance large-deformation anchor core device maintains a stable working resistance of approximately 350 kN within a 396–405 mm tensile deformation range, significantly enhancing the support system’s crack-resistant capacity under pressure. The focused jet directs cracks to penetrate along predetermined paths, forming planar damage zones and effectively suppressing vertical damage to the surrounding rock. Based on field monitoring, the tunnel was divided into advance support zones, temporary support zones, and stable tunnel sections, enabling a differentiated support scheme. The engineering application achieved stable tunnel retention and safe reuse. This study provides key theoretical foundations and technical approaches for controlling rock mass stability in similar tunnel conditions. Full article

Buried, battery-free sensor nodes offer a promising solution for structural health monitoring, reducing maintenance and improving infrastructure sustainability by monitoring slow-varying parameters such as temperature and humidity, which do not require high sampling frequencies. This study shows the practical implementation of an autonomous LoRa node powered solely by RF energy harvested from a gateway using an 868 MHz rectenna and a custom energy management circuit charging a supercapacitor. Experimental characterization revealed that, with a single rectenna placed 40 cm from the gateway, communication intervals ranged from 58 min (+14 dBm) to 10 min (+20 dBm), clearly linking available RF power and energy management to achievable monitoring frequency. To further illustrate this, deploying a multi-element rectenna array enabled reliable node operation at distances greater than 10 m, demonstrating that the number of rectenna elements is the dominant factor governing harvested energy and the achievable operating range. Configuring the gateway as both a communication hub and an energy source further simplified deployment. These results highlight strategies for overcoming power delivery constraints in deeply embedded wireless sensing applications for civil structures. Full article

The influence of back-gate (BG) bias on the breakdown voltage (BV) of lateral SOI power devices is investigated using TCAD simulations. A reference SOI-LDMOS structure with BVREF = 73.7 V, optimized based on RESURF and charge-sharing principles, is selected as the baseline for analysis. The BV response to BG bias is shown to fall into three distinct regimes: (i) a linear decrease with increasing magnitude of negative BG bias (−65 V ≤ VG2 ≤ −5 V), (ii) an invariant region where the BV reaches its maximum value (−5 V ≤ VG2 ≤ +10 V), and (iii) a sharp reduction under increasing magnitude of positive BG bias (+10 V ≤ VG2 ≤ +65 V). Qualitative analysis of impact ionization and charge distribution confirms that inversion, depletion, and accumulation conditions in the drift region govern these behaviors. Furthermore, parametric variations in drift doping, drift thickness, and buried oxide thickness reveal significant shifts in the optimum design window, with the buried oxide thickness emerging as a critical factor for ensuring robustness of BV under BG bias. These results provide valuable design guidelines for achieving stable high-voltage performance in practical SOI-LDMOS power devices. Full article

To learn more about the problem of blast weakening in shallow-buried and extra-thick coal seams, Panjin coal mine was used to provide the engineering background for this study. The influence of blast weakening technology on the vibration of ground buildings was investigated. Based on monitoring the vibration data from the final 400 m of the working face, we established the Sadovsky formula for this coal mine through regression. The maximum safe charge of one blast at different distances was obtained. A numerical model was established and compared with field monitoring data to verify its accuracy. This numerical model was used to analyze the influence of blast weakening vibrations on ground buildings during the final mining stage. Finally, the maximum safe charge for one blast at advancing distances from the working face was derived based on numerical calculation results. It was compared with the maximum safe charge obtained from field measurements. The results show that both exhibit significant consistency, and the maximum safe charge of one blast decreases as the working face advances. In addition, the peak vibration velocity at each monitoring point does not exceed 0.2 cm/s for the remaining 400 m of the measured working face, which is lower than the allowable safety value for blasting vibrations. In the numerical simulation of the final mining stage at 200 m, the ground vibration velocity is largest for the district office, second-largest for the chimney, and smallest for the science and technology building. The maximum vibration velocity and effective stress in the three directions of the three buildings are within the allowable range, indicating that the buildings remained in a safe state. Full article

In order to clarify the pore evolution and coupling characteristics with hydrocarbon charging in the deep-buried ultra-tight sandstone reservoirs of the second member of Xujiahe Formation (hereinafter referred to as the Xu 2 Member) on the eastern slope of the Western Sichuan Depression, this study integrates burial history and thermal history with analytical methods including core observation, cast thin section analysis, scanning electron microscopy, carbon-oxygen isotope analysis, and fluid inclusion homogenization temperature measurements. The Xu 2 Member reservoirs are predominantly composed of lithic sandstones and quartz-rich sandstones, with authigenic quartz and carbonates as the main cementing materials. The reservoir spaces are dominated by intragranular dissolution pores. The timing of reservoir densification varies among different submembers. The upper submember underwent compaction during the Middle-Late Jurassic period due to the high ductility of mudstone clasts and other compaction-resistant components. The middle-lower submembers experienced densification in the Late Jurassic period. Late Cretaceous tectonic uplift induced fracture development, which enhanced dissolution in the middle-lower submembers, increasing reservoir porosity to approximately 5%. Two distinct phases of hydrocarbon charging are identified in the Xu 2 Member. The earlier densification of the upper submember created unfavorable conditions for hydrocarbon accumulation. In contrast, the middle-lower submembers received hydrocarbon charging prior to reservoir densification, providing favorable conditions for natural gas enrichment and reservoir formation. Three sweet-spot reservoir development patterns are recognized: paleo-structural trap + (internal source rock) + source-connected fracture assemblage type, paleo-structural trap + internal source rock + late-stage fracture assemblage type, and paleo-structural trap + (internal source rock) + source-connected fracture + late-stage fracture assemblage type. Full article

Proteins and their surrounding hydration water engage in a dynamic interplay that is critical for maintaining structural stability and functional integrity. However, the intricate coupling between protein dynamics and the structural order of hydration water remains poorly understood. Here, we employ all-atom molecular dynamics simulations to investigate this relationship across four representative proteins. Our results reveal that protein residues with greater flexibility or solvent exposure are surrounded by more disordered hydration water, akin to bulk water, whereas rigid and buried non-polar residues are associated with structurally ordered hydration shells. Due to their strong hydrogen bonding and electrostatic interactions, charged residues exhibit the most disordered hydration water, while non-polar residues are associated with the structurally most ordered hydration water. We further uncovered a positive correlation between the relaxation dynamics of protein residues and their hydration water: slower (faster) protein relaxation is coupled with slower (faster) relaxation of the structural order of hydration water. Notably, this coupling weakens with increasing residue flexibility or solvent exposure, with non-polar residues displaying the strongest coupling, and charged residues the weakest. To further uncover their coupling mechanism, we elucidate residue-specific coupled fluctuations between protein residues and hydration water by generating scatter plots. These findings provide a comprehensive understanding of the mechanisms underlying protein–water interactions, offering valuable insights into the role of hydration water in protein stability, dynamics, and function. Full article

Lead halide perovskite solar cells (PSCs) have shown tremendous progress in the last few years. However, highly toxic Pb and its instability have restricted their further development. On the other hand, antimony-based perovskites such as cesium antimony iodide (Cs₃Sb₂I₉) have shown high stability but low power conversion efficiency (PCE) due to the limited transfer of photocarriers and the poor quality of films. Here, we present a novel method to improve the performance of Cs₃Sb₂I₉ PSCs through a FACl-modified buried interface. FACl acts as a bi-functional additive, and FA incorporation enhances the crystallinity and light absorption of films. Furthermore, treatment with FACl optimizes the level position of Cs₃Sb₂I₉. In addition, transient photovoltage and transient photocurrent were employed to confirm the reduction of charge recombination and superior carrier transportation. By using a planar device structure, we found the PCE of a FACl–Cs₃Sb₂I₉-based device to be 1.66%. The device, stored for 2 months under N₂ conditions, showed a negligible loss in PCE. Overall, this study provides a new strategy to further enhance the performance of Sb-based PSCs. Full article