Stacking Structure Research Articles

Orthogonal hologram memory extending from visible to UV mediated with TaOx/TiO2:Ag heterojunctions

The photon-energy conversion covering the full spectral wave band is crucial for detecting and storing information. Schottky junctions in nanoscale such as TiO2:Ag enable multicolor photochromism and information storage in the visible region. However, the photoelectrons from the UV-excited semiconductor cause the loss of information. It has become a big challenge to the data memory of Schottky junctions extending from the visible to UV band. Herein, we construct a stacked heterojunction structure of TaOx/TiO2:Ag as a full wave band holographic memory. Coherent green laser beams are utilized to inscribe a Fourier transform hologram, followed by burning a computer-generated hologram in a focused UV laser spot array. The holographic array based on UV photothermal effect presents high refractive index modulation in the stacked layered oxide film. Meanwhile, the excellent UV protection of TaOx/TiO2 heterojunctions makes it possible to fully preserve previously written Fourier transform holographic data. Information cross talk between the two kinds of holograms is almost inhibited. This work provides a bright way for high-density data storage, wideband optical detection, and advanced manufacturing of micro-optical components.

Investigation of the effects of tri-ammonium citrate electrolyte additive for lead-acid battery using lead foil as negative grid

This study aims to create a lead foil anode for lead-acid batteries with high specific energy, lightweight, and corrosion-resistant. The research also discovered that incorporating tri-ammonium citrate (AC) into the electrolyte significantly enhances the cycling performance of the pure lead level foil negative electrode under high-rate-partial-state-of-charge (HRPSoC) conditions. This addition also increases the specific capacity at high rates, resulting in a 2.3-fold improvement in HRPSoC cycling performance at a 1C rate and a 52 % increase in discharged capacity at a 4C rate, compared to the control blank plate without AC. Through X-ray diffraction (XRD), scanning electron microscope (SEM), and other material characterization methods, as well as electrochemical tests, it is proved that AC improves the morphology of lead sulfate into a lamellar stacked structure. It can also effectively refine lead sulfate grains and inhibit sulfation. In addition, pure lead foil batteries exhibit superior capacity cycle stability at a high multiplication rate compared to grid lead-based alloy batteries. Pure lead foil batteries also have a significantly longer cycle life, with a 65 % increase in discharge-specific capacity at a 4C multiplication rate and a 2.2 times and 1.8 times increase in cycle life at 1C and 2C multiplication rates, respectively.

Vacuum assisted desorption of sodium zirconate sorbent for enhancing cyclic stability in pre-combustion CO2 capture

Sodium zirconate (Na2ZrO3) is a promising material for pre-combustion CO2 capture due to its fast sorption kinetics and excellent cyclic stability at high temperatures under ideal condition (desorption in 100% N2). Still, there is a lack of study on the performance of Na2ZrO3 cyclic capture under harsh condition (desorption in high concentration CO2). In this study, Na2ZrO3 was prepared by wet-mixing and heated-drying, and the difference in the cyclic CO2 capture performance of the sample was compared between desorption under harsh condition and vacuum condition. The crystal structure of Na2ZrO3 was identified during the sorption-desorption cycles. The crystal structure was also modeled and simulated to analyze the reason for the superior capture performance from the monoclinic Na2ZrO3. It was found that the special interlocked and multilayered stacked structure of the monoclinic Na2ZrO3 allowed for high reactivity with CO2. It was found that high temperature solely had little help in the desorption of Na2ZrO3 under harsh condition, but vacuum condition promoted desorption of Na2ZrO3 in high fraction CO2, and vacuum desorption at 1000 °C-1050 °C resulted in Na2ZrO3 with both good capture performance and cycling stability. Vacuum desorption led to more complete reversion of Na2ZrO3 to the monoclinic state, benefiting for CO2 capture. This study attempted to simulate the harsh capture environments of real industrial applications and to explore the possibility of Na2ZrO3 as a carbon capture material for pre-combustion capture.

Interface Engineering: Enhanced Catalysis Through Precise Control of Metal Nanocluster Transformation.

Atomically precise metal nanoclusters (NCs) have garnered significant interest due to their unique atomic stacking structures, the effect of quantum confinement, and enriched active sites but suffer from thermal- or light-induced poor instability and self-aggregation, together with in situ self-conversion to conventional metal nanoparticles (NPs). How to effectively harness the generic detrimental self-transformation property of metal NCs has so far not garnered immense attention within the realm of catalysis. In this work, we develop a layer-by-layer assembly technology to accurately anchor metal NCs to the metal oxide matrix. Then, the anchoring of metal NCs to metal NPs is triggered by a simple thermal treatment that enables precise control over the interface structure, resulting in a hollow core-shell heterostructure with a metal core (Au, Ag) encapsulated by a metal oxide (CeO2, Fe2O3, SnO2) shell. Benefiting from the synergistic interplay between metal NPs and the metal oxide substrate, such self-assembled metal NPs@metal oxide heterostructures display excellent catalytic activities and stability in the reduction of aromatic nitro compounds. The detailed catalytic mechanism is elucidated. Our work offers fresh impetus for the judicious utilization of the inherent instability of metal NCs for catalytic selective organic transformation.

Prediction of transient thermal stress distribution in SOFC based on coupled computational fluid dynamics and thermodynamics modeling

Long-term stability and safety are two key factors for the application of solid oxide fuel cell (SOFC) technology, with thermodynamics playing a central role in influencing this stability. Thus, understanding the thermodynamic behavior within SOFC and how it will depend on the stack structure are very important, especially at the start and stop stages. In this study, a 3D calculated fluid dynamics model and thermomechanical coupling model based on the actual component structures are established. We place emphasis on understanding how these factors evolve during dynamic phases, shedding light on the transient thermal stress behavior of the SOFC. The influence of different interconnect structures on the thermal stress distribution is studied. The coupling calculation results show that the first principal stress of the electrolyte is significantly affected by the specific interconnect structure. Adopting cylindrical ribs instead of rectangular ribs, the thermal stresses of the SOFC components can be reduced by 13–25 %, respectively.

Skin-inspired bimodal pressure sensor for static and dynamic intelligent interactive perception system

With the rapid development of flexible pressure sensors, it is difficult for single-function devices to meet the demands of complex intelligent interactive scenarios. In this paper, a skin-inspired single electrode triboelectric nanogenerator (S-TENG)-ionic capacitive pressure sensor (IPS) bimodal pressure sensor with a top-down stacked structure is developed. The designed sensor not only exhibits high sensitivity, wide pressure detection range, fast response/recovery time, and long-term durability, but also detects external dynamic and static mechanical responses. Based on these superiorities, the designed sensor has been successfully applied in three practical intelligent interactive scenarios, including a music player system using IPS perception array, an intelligent handwriting perception system using S-TENG, and an intelligent material and shape perception system constructed by a bimodal pressure perception array. Expectably, the proposed bimodal pressure sensor can realize intelligent interactive perception in complex application scenarios, which provides a new paradigm for next generation of flexible pressure sensors.

Low-Power Radiation-Hardened Static Random Access Memory with Enhanced Read Stability for Space Applications

In space environments, radiation particles affect the stored values of SRAM cells, and these effects, such as single-event upsets (SEUs) and single-event multiple-node upsets (SEMNUs), pose a threat to the reliability of systems used in the space industry. To mitigate the impacts of SEUs and SEMNUs, this paper proposes the Read Stability Improved and Low Power (RSLP16T) SRAM cell. It was confirmed that in SEU-induced simulations, all nodes of the RSLP16T could be restored with a charge amount of less than 100 fC. Additionally, it was verified that a similar level of restoration was possible for SEMNUs occurring in pair of storage nodes. The proposed cell achieves a high level of read stability due to a high pull-down cell ratio (current ratio, CR) at the storage nodes and the fact that only a pair of nodes is in contact with the bit lines during read operations. Because all node paths use a stacking structure for internal transistor configuration and a relatively higher number of cells are composed of PMOS, it consumes the least hold power. While these improvements come at the cost of slightly increased delay time and area, performance evaluation revealed that the equivalent quality metric (EQM) was the highest, indicating that the benefits outweigh the drawbacks. The proposed integrated circuit is implemented in the 90 nm CMOS process and operated on 1 V supply voltage.

Engineering 2D Materials from Single-Layer NbS2.

Starting from a single layer of NbS2 grown on graphene by molecular beam epitaxy, the single unit cell thick 2D materials Nb5/3S3-2D and Nb2S3-2D are created using two different pathways. Either annealing under sulfur-deficient conditions at progressively higher temperatures or deposition of increasing amounts of Nb at elevated temperature result in phase-pure Nb5/3S3-2D followed by Nb2S3-2D. The materials are characterized by scanning tunneling microscopy, scanning tunneling spectroscopy, and X-ray photoemission spectroscopy. The experimental assessment combined with systematic density functional theory calculations reveals their structure. The 2D materials are covalently bound without any van der Waals gap. Their stacking sequence and structure are at variance with expectations based on corresponding bulk materials highlighting the importance of surface and interface effects in structureformation.

Low-cost Ca/Mg co-modified biochar for effective phosphorus recovery: Adsorption mechanisms, resourceful utilization, and life cycle assessment

Effective recovery of phosphorus from wastewater and reutilization are important for controlling water eutrophication and achieving resourceful utilization of pollutants. In this study, a low-cost, eco-friendly, and highly efficient Ca/Mg co-modified coffee grounds biochar (CMBC) was synthesized in one step for phosphorus adsorption, and the potential application of the phosphorus absorbed CMBC (CMBC-P) as a fertilizer was also explored. The results showed that the surface of CMBC was covered by granular calcium/magnesium oxides with a rougher layered stacking structure. The adsorption capacity of CMBC for phosphorus has been significantly improved compared with that Ca or Mg modification, with the maximum adsorption capacity reached 144.31 mg/g. The mechanisms primarily involve surface precipitation, complexation, ligand exchange, and electrostatic attraction. Density functional theory calculation revealed that the Ca-based active sites were the main binding sites (−6.58 and −6.41 Kcal/mol) for phosphorus compared with that of the Mg (−0.89 Kcal/mol). Natural aging experiment showed that approximately 74.87 % of the adsorbed phosphorus can be released to soil within 60 days and the soil available phosphorus also increased significantly. The CMBC-P also significantly enhanced the germination and growth of plants. Moreover, life cycle assessment revealed that the production of CMBC emitted only 8.38 kg CO2 eq, and a more environmentally friendly approach was also proposed. Cost benefit analysis confirmed the exceptional cost-effectiveness (15.15 g P/$) of CMBC among various adsorbents. Overall, CMBC demonstrated excellent potential for removal phosphorus from water and further use as a phosphorus fertilizer.

Microstructural stability enhancement and mechanical reinforcement of TLP-bonded Cu/Sn-3.5Ag/Cu microbumps under multiple reflow cycles through Zn Alloying and Ni substrate integration

The transient liquid phase (TLP) bonding process is effective for constructing stacked structures in advanced packaging, as it allows for multiple reflow cycles without remelting. However, the various reflows can cause phase transformations, leading to internal stress-induced voids. Thus, the stability of IMC phases is particularly challenged in 3D stacking structures. Common configurations include Cu/Sn/Cu and Cu/Ni/Sn/Cu. Although Ni improves the stability of the Cu6Sn5 phase, phase transformation to Cu3Sn can still occur, compromising reliability. This study investigates microstructure stability by doping Zn into the Cu/Sn-3.5Ag/Ni system across five reflow cycles. Results demonstrate that Cu-15Zn/Sn-3.5Ag/Ni microbumps reduce void formation and ensuring the phase stability of the (Cu,Ni)6(Sn,Zn)5 to maintain the microstructure stability. The Zn addition inhibits the Cu3Sn layer, while optimizing grain size and orientation of (Cu,Ni)6(Sn,Zn)5. (Cu,Ni)6(Sn,Zn)5 also exhibits increased hardness and reduced modulus (Er). These findings provide critical insights for designing sub-10-μm scale TLP-bonded microbumps in advanced packaging.

Experimental, modeling, and numerical simulation of ultrasonic assisted drilling of CFRP/Ti stacks

Carbon fiber reinforced polymer (CFRP) and Ti-6Al-4V alloy (Ti) stacks structures are increasingly utilized in aircraft load-bearing applications, where the quality of hole processing significantly impacts their connection performance. Conventional drilling (CD) methods for CFRP/Ti stacks often encounter challenges such as severe interface damage, high cutting forces, and excessive heat generation. This study investigates the application of ultrasonic-assisted drilling (UAD) on CFRP/Ti stacks by integrating finite element method (FEM) modeling with experimental approaches to analyze the machinability of these materials under different machining methods and parameters. A self-developed high-frequency vibration spindle was employed to process CFRP/Ti stacks using both CD and UAD techniques. The newly developed numerical model effectively elucidates the mechanical and thermal coupling involved in the machining process and the transfer behavior of temperature and stress at the laminate interface. The experimental results of cutting force, hole inlet and outlet surface morphology, inner wall condition, chips, tool wear, etc. under different machining parameters were studied and analyzed. To ensure the reliability of our findings, experimental data were validated against simulation results. The findings reveal that UAD, when optimal separation conditions are achieved, significantly reduces cutting forces and enhances the surface morphology of both the inner and outer hole surfaces. Specifically, UAD lowers cutting forces by 27.2 % and the damage coefficient (Fd) by 15.7 % compared to CD. Furthermore, the high-frequency vibration generated by UAD markedly extends tool life. The specially designed high-frequency vibration spindle successfully meets drilling requirements, thereby significantly improving the machining performance of CFRP/Ti stacks materials, and it provides a certain reference for practical industrial applications.

Synthesis Pathway Oriented Heterogeneous Stacking Mode of Homogeneous Two-Dimensional Hydrazone-Linked COFs

The study of isomerism phenomena in covalent organic frameworks (COFs), such as dimensional isomerism, interpenetration isomerism, and stacking isomerism, along with their influence on the properties of COFs, has become an intriguing research avenue in recent years. Nevertheless, the current techniques for synthesizing COF isomers predominantly rely on extensive trial and error, lacking efficient, target-driven synthetic methodologies. The development of synthetic protocols capable of selectively enhancing the crystallization of one COF isomer over another continues to pose a significant challenge, remaining an empirical process at present. In this work, through subtly designing with the same structure and different stacking modes, we elucidate how altering the sequence of hydroxyl site modifications on the monomer impacts dissolution, polymerization, and assembly processes during COF synthesis, thereby influencing the stacking modes of two kinds of hydrazine-linked COFs with reversed AA stacking and AA stacking structures. The quasi-in-situ PXRD analysis during methanol volatilization and the N2 adsorption experiments revealed that the crystallinity and stability of the COFs prepared by the pre- and post-modified method are significantly different. These structural differences are further reflected in applications such as photocatalytic reduction of uranium and iodine adsorption. This work sheds light on the crucial role of non-covalent interactions in influencing and regulating the stability-crystallinity-functionality of COFs, offering valuable insights for future investigations.

Molecular simulation of asphaltene clustering in toluene and n-heptane: Thermodynamics and dynamics aspects

This study investigated the thermodynamic and dynamic properties of asphaltene molecules in Toluene and n-Heptane using the OPLS-AA force field in the GROMACS package at 300 K and 1 bar. The results indicate that van der Waals (vdW) interactions have a significant influence on thermodynamics, accounting for around 88–90 % of the total interaction energy between asphaltene molecules, while Coulombic (Coul) interactions contribute approximately 10–12 %. Stable asphaltene aggregates form at concentrations equal to or greater than 8 asphaltene molecules in 4000 molecules of Toluene. The interaction energy between asphaltene chains, which promotes aggregation, is much weaker than the interaction between aromatic rings. Longer chains exhibit more attractive vdW interactions and more repulsive Coul interactions. The presence of heteroatoms (sulfur and oxygen) hinders the parallel and symmetrical interaction of asphaltene molecules. Density profiles and two-dimensional maps were used to analyze the spatial arrangement of asphaltenes. A total interaction energy equal to or more positive than −300 kJ/mol for asphaltene-liquid interactions is introduced as a criterion for classifying a liquid as an asphaltene precipitator. The polarity of the solvent was inferred not to affect asphaltene solubility. In n-Heptane, asphaltene molecules aggregated to form a dense nucleus, while in Toluene, sharp peaks in the density profiles indicated the formation of clusters of varying sizes via asphaltene aggregation. Systems containing 64 and 32 asphaltene molecules had the highest probability of forming clusters comprising 10–16 and 12–16 asphaltene molecules, respectively. In Toluene, the average cluster sizes ranged from 1.4 to 6.1 molecules, depending on asphaltene concentration. Cluster size analysis showed variations in both size and stacking architectures, including face-to-face stacked and T-shaped aggregates. The proportion of face-to-face stacked structures was higher than T-shaped structures in both Toluene and n-Heptane, with the ratio of face-to-face stacked to T-shaped aggregates estimated at ∼2.9. While thermodynamic equilibrium was well attained, simulation times longer than 150 ns are recommended to achieve dynamic equilibrium.

Structural Transition Analysis of Bilayer Black Phosphorus under High Pressure via Ultralow-Frequency Raman Spectroscopy.

The unique anisotropic electron-photon and electron-phonon interactions of black phosphorus (BP) set it apart from other isotropic 2D materials. These anisotropic properties can be adjusted by varying the stacking thickness and sequence as well as by applying external pressure and strain. In contrast to multilayer or bulk BP, the effects of pressure on bilayer BP are still not fully elucidated. This study presents experimental evidence that explores the high-pressure response (0-20 GPa) of bilayer BP within the extreme low Raman shift region (5-150 cm-1), aiming at verifying structural phase transitions and stacking sequence variations. Notably, phase transitions were observed at ∼7 GPa for the orthorhombic to rhombohedral transition and at ∼14-16 GPa for a further transition to a simple cubic structure. The effects of pressure on bilayer BP with three distinct stacking sequences (AA, AB, and AC) were analyzed using angular-resolved polarized Raman spectroscopy (ARPR). The recovery of all characteristic Raman modes after the application of pressure substantiates the reversibility of the structural phase transitions in bilayer BP across all three stacking sequences. However, significant alterations in the stacking sequences were observed before and after the application of hydrostatic pressure. Specifically, AA and AC stacking sequences showed a tendency to relax into an optimized interlayer AB stacking structure upon the release of pressure from 20 to 0 GPa. This observed change in the stacking sequences of bilayer BP under pressure is detected for the first time in this work. The pressure-induced modifications in the stacking sequences, and consequently in the anisotropic properties of bilayer BP, highlight its potential as a promising material for pressure- (or strain-) sensitive optoelectronic nanodevices. Additionally, this study offers novel insights into the analysis of anisotropic interlayer interactions in other van der Waals-stacked 2D materials.

Excellent energy storage performance of multi-alternating-layer structured PMMA/PVDF dielectric composite at high-temperature

Polymer dielectric capacitors have high power density and are an integral component of electronic and power device. Currently, the limited energy density restricts their further application. In this research, a novel method was designed to optimize performance of PMMA/PVDF composite via an alternating stacked multi-layer structure. And, the five-alternating-layer of PVDF-PMMA-PVDF-PMMA-PVDF (F-A-F-A-F) composite has excellent dielectric properties, for instance, a better dielectric constant (4.52@1 kHz) and a low dielectric loss (0.034@1 kHz). The discharge energy density (Ue) of it is significantly larger than that of PMMA and PVDF. Particularly, the Ue of F-A-F-A-F composite is increased by 83.0 % (from 4.71 J/cm3 to 8.62 J/cm3) with charging-discharging efficiency of 60 % at 80 °C. Moreover, the F-A-F-A-F composite achieves an excellent stability after 40,000 cycles. This composite has a wide range of potential applications in the field of traditional dielectric capacitor due to its good energy storage performance and cycle stability.

Immobilization of arsenic wastes and retardation effect on cement hydration: Experimental and molecular dynamic analysis

AbstractThis work was designed to investigate the influence of arsenic dosage, variety on the mechanical properties, hydration, and solidification from the perspective of Portland cement (PC) performance evolution. The results demonstrate that using PC could solidify the arsenic wastes effectively, with arsenic leaching concentrations consistently below 5 mg/L. Arsenic wastes retard cement hydration, leading to a slower rate of hydrates formation, disrupting the calcium silicate hydrate (C–S–H) stacking structure, and thus detrimental to strength development especially at early age. The adverse effect is highly dependent on the arsenic variety. The insoluble calcium arsenate exhibits the least impact, while the arsenates show the largest challenging to immobilization due to the instability of hydrates. Molecular dynamic simulation indicates that arsenic can be chemically immobilized with Ca2+, and be physically adsorbed onto the positively charged C–S–H by forming As‐O···Ca···Si‐O units, accompanied by a significant reduction in adsorption energy by 46.5%. The arsenic solidification behavior provides a basis for the resource utilization of arsenic wastes in cementitious materials.

A novel benign and malignant classification model for lung nodules based on multi-scale interleaved fusion integrated network

One of the precursors of lung cancer is the presence of lung nodules, and accurate identification of their benign or malignant nature is important for the long-term survival of patients. With the development of artificial intelligence, deep learning has become the main method for lung nodule classification. However, successful deep learning models usually require large number of parameters and carefully annotated data. In the field of medical images, the availability of such data is usually limited, which makes deep networks often perform poorly on new test data. In addition, the model based on the linear stacked single branch structure hinders the extraction of multi-scale features and reduces the classification performance. In this paper, to address this problem, we propose a lightweight interleaved fusion integration network with multi-scale feature learning modules, called MIFNet. The MIFNet consists of a series of MIF blocks that efficiently combine multiple convolutional layers containing 1 × 1 and 3 × 3 convolutional kernels with shortcut links to extract multiscale features at different levels and preserving them throughout the block. The model has only 0.7 M parameters and requires low computational cost and memory space compared to many ImageNet pretrained CNN architectures. The proposed MIFNet conducted exhaustive experiments on the reconstructed LUNA16 dataset, achieving impressive results with 94.82% accuracy, 97.34% F1 value, 96.74% precision, 97.10% sensitivity, and 84.75% specificity. The results show that our proposed deep integrated network achieves higher performance than pre-trained deep networks and state-of-the-art methods. This provides an objective and efficient auxiliary method for accurately classifying the type of lung nodule in medical images.

Water-Driven Stacking Structure Transformation of Ultrathin Ru Nanosheets for Efficient Hydrogen Evolution Reaction.

Ultrathin crystalline materials are a class of popular materials that can potentially exhibit fascinating physical and chemical properties dictated by their unique stacking freedom. However, it is challenging to achieve the controllable synthesis over their stacking structure for ultrathin crystalline materials. Herein, water is employed as a key regulatory factor to realize phase engineering in ultrathin nanosheets (NSs), thereby altering stacking faults to achieve distinct stacking arrangements. Ruthenium (Ru) NSs with consistent specific surface areas but different stacking manners are fabricated through the systematic regulation of water. Based on this, it is demonstrated that the hydrogen evolution reaction (HER) performance can be significantly influenced by their stacking structures. Further in-depth investigations reveal that the distinct stacking structures of Ru NSs, featuring a limited area of side facets, will influence the energy barrier of sluggish Volmer step in HER. Ru NSs with ABC stacking exhibit an accelerated Volmer process with outstanding catalytic activity, demonstrating a remarkably low overpotential (25mV at 10mAcm-2) and Tafel slope (29mVdec-1) than most of the reported HER catalysts. The work will advance the understanding of controllable synthesis methods and illuminate the structure-activity relationships in ultrathin crystalline nanomaterials.

Silica nanofiber membrane with high reflectivity and low absorptivity for high-energy laser protection (29.0 kW/cm2)

To safeguard against high-energy continuous wave laser, the chosen strategy is a robust reflection to restrict heat generation instead of thermal protection. Based on this, the SiO2 nanofiber membranes (0.12 g/cm3) with nearly 100% reflectivity and an extremely low absorption coefficient, were fabricated by electrospinning under the optimal parameters and calcinating at 600-1000 °C. The membranes, with a thickness of 4 mm, exhibit the best laser protection property reported to date. Under laser irradiation of 29.0 kW/cm2, they remain intact and achieve a steady state after 10 s with a rear temperature of only 700 °C because the necessary conditions for excellent laser protection property—the absence of highly absorbing groups, moderate fiber stacking density, presence of fiber stacking structure, chemical inertness, and specific thickness—are all met. In addition, excellent mechanical properties, including a tensile strength of 16.6 MPa (normalized value through equivalent solid materials for comparison purposes), a compressive strength of 0.07 MPa, and good bending performance, provide guarantees for their practical applications.

Effect of Water Vapor Partial Pressure on the Structure of Blue Tungsten Reduction Products in Hydrogen

This study investigates the structural evolution of blue tungsten reduction products when exposed to hydrogen under controlled water vapor partial pressures. The reduction of WO₂.₉ was achieved through hydrogen atom diffusion at 1050 °C. The Results indicate that, at low water vapor partial pressure, the reduction process of blue tungsten initiates on the surface and progresses inward, creating surface cracks on the clusters. These cracks enable water vapor to interact with the reduced tungsten (W) at their base, leading to the formation of needle-like WO₂.₇₂ phases that grow outward. Under high water vapor partial pressure, the morphology of the acicular WO2.72 phase changes to a stacked structure. Additionally, W-OH bonds were identified in the reduction products, with the WO₂.₇₂ growth angles observed at approximately 12° relative to the tungsten particles, closely matching the interfacial model prediction of 13.41°. The results of this paper will provide theoretical support for the structural evolution of intermediate products during hydrogen reduction of blue tungsten.