Journal of Materials Processing Technology最新文献

{"title":"Numerical modeling and analysis of stress-induced anisotropic damage and evolution mechanism of YAG single crystals during diamond cutting","authors":"Shayu Song,&nbsp;Jixiang Ding,&nbsp;Zixuan Chen,&nbsp;Rongtao Shen,&nbsp;Jianguo Zhang,&nbsp;Junfeng Xiao,&nbsp;Jianfeng Xu","doi":"10.1016/j.jmatprotec.2025.119186","DOIUrl":"10.1016/j.jmatprotec.2025.119186","url":null,"abstract":"<div><div>Yttrium aluminum garnet (YAG) is widely used in optical systems, yet its anisotropic behavior during ultra-precision diamond cutting remains insufficiently understood. This work investigates the anisotropic damage of (111) YAG during diamond cutting through experiments, numerical simulations, and data-driven analysis. A numerical model incorporating material properties, cutting forces, and stress fields during diamond cutting was established, along with an innovatively proposed stress-driven surface/subsurface deformation model. Minimal damage was observed along the [1−12,-211], and [1−21] directions, while the [1−10,01−1], and [-101] directions showed severe damage, revealing that damage evolves from pits and craters to microcracks and shell fractures, tendentiously aligned with plastic flow and slip directions. TEM validation showed that the least-damaged groove exhibits layered subsurface deformation basically matching numerical predictions, while the most-damaged groove presents crack-like but non-open defects matching cognitive predictions. Combined analysis further revealed that the {220} family of planes constitutes the primary deformation plane in YAG cutting. Ridge-regression analysis quantifies factor contributions, showing that shear modulus dominates the damage level, while stress and Schmid factor exhibit scale-dependent effects. This integrated approach offers both physical insight and quantitative analysis for understanding and optimizing ultra-precision machining of brittle, anisotropic materials.</div></div>","PeriodicalId":367,"journal":{"name":"Journal of Materials Processing Technology","volume":"348 ","pages":"Article 119186"},"PeriodicalIF":7.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Corrigendum to \"Regulation of PBF-LB/M melt pool oscillation behavior via beam shaping: A study based on time-frequency characteristics of coaxial radiation signals\" [J. Mater. Process. Technol. 348 (2026) 119181]","authors":"Tao Zhu ,&nbsp;Xiangjun Xiang ,&nbsp;Qiang Gong ,&nbsp;Jiaxing Wen ,&nbsp;Lai Wei ,&nbsp;Tian Huang ,&nbsp;Hongkai Jin ,&nbsp;Changqiu Chen ,&nbsp;Huabin He ,&nbsp;Kaihua Sun ,&nbsp;Xianfeng Shen ,&nbsp;Shuke Huang","doi":"10.1016/j.jmatprotec.2025.119191","DOIUrl":"10.1016/j.jmatprotec.2025.119191","url":null,"abstract":"","PeriodicalId":367,"journal":{"name":"Journal of Materials Processing Technology","volume":"348 ","pages":"Article 119191"},"PeriodicalIF":7.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145973090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Laser shock peening of TiC/Inconel 625 composites fabricated via cored wire arc additive manufacturing","authors":"Le Jia ,&nbsp;Hao Yi ,&nbsp;Huajun Cao ,&nbsp;Jun Luo","doi":"10.1016/j.jmatprotec.2025.119190","DOIUrl":"10.1016/j.jmatprotec.2025.119190","url":null,"abstract":"<div><div>The increasing demand for high-performance alloys such as Inconel 625 in extreme environments challenges conventional additive manufacturing due to constraints in build size, geometrical accuracy, and mechanical performance. Cored wire arc additive manufacturing provides a promising alternative for fabricating high-performance and multi-material components but suffers from poor surface quality and internal porosity. In this work, laser shock was integrated into the cored wire arc additive manufacturing process to regulate molten pool behavior and enhance layer consolidation. The combined effects of laser shock and torch inclination were systematically investigated. Results indicate that torch inclination promotes droplet transfer and increases energy input, thereby improving deposition stability, with a 45° inclination yielding the optimal morphology. Furthermore, an optimized laser shock peening strategy was established through theoretical analysis, numerical simulation, and experimental validation. Laser shock peening effectively refines the microstructure, enhances TiC-matrix interfacial bonding, and introduces high-density dislocations and twins, collectively reducing defects and improving mechanical and tribological performance at different temperatures. The dominant wear mechanism transitions from severe adhesive and abrasive wear to mild oxidative and micro-abrasive modes, with oxidative wear prevailing at elevated temperatures. Compared with conventional cored wire arc additive manufacturing, the laser shock peening-cored wire arc additive manufacturing hybrid exhibits significant improvements in ultimate tensile strength, yield strength, and elongation by 7.8 %, 10.8 %, and 23.9 %, respectively, demonstrating a synergistic enhancement in both strength and ductility. This work presents an effective approach to regulate forming quality and performance in cored wire arc additive manufacturing, providing insights for advancing wire arc additive manufacturing-based high-performance manufacturing of metal matrix composites.</div></div>","PeriodicalId":367,"journal":{"name":"Journal of Materials Processing Technology","volume":"348 ","pages":"Article 119190"},"PeriodicalIF":7.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis and experiment on deep drawing of aluminum thin-walled shells with local reverse bulging","authors":"Wen Sun ,&nbsp;Wei Liu ,&nbsp;Shijian Yuan","doi":"10.1016/j.jmatprotec.2025.119150","DOIUrl":"10.1016/j.jmatprotec.2025.119150","url":null,"abstract":"<div><div>Wrinkling is a major challenge in the deep drawing of ellipsoidal thin-walled aluminum alloy shells, limiting the application of such parts in lightweight structural components. In this study, a modified deep drawing process with actively controlled local reverse bulging was proposed to suppress wrinkling by regulating the stress state via local reverse bulging deformation. To investigate the deformation mechanism and defect control of this process, a geometric model was established to reveal the geometric constraints in the reverse bulging area. A theoretical model based on the energy method was developed to determine the critical wrinkling stress. Defect under different process parameters was predicted using a combined-criteria approach incorporating geometric constraints, wrinkling criteria, and instability criteria. A deep drawing device equipped with a servo-controlled local rigid tool was designed and used to conduct experiments. Moreover, critical wrinkling stress and stress distribution were analyzed for different process parameters. The results show that the proposed process can effectively suppress wrinkling by regulating the stress distribution. The combined-criteria approach agrees well with the experimental results and provides valuable guidance for optimizing process parameters in such ellipsoidal thin-walled shells. This study provides theoretical and experimental guidance for defect control in deep drawing with actively controlled local reverse bulging, and offers a novel method for thin-walled shell forming.</div></div>","PeriodicalId":367,"journal":{"name":"Journal of Materials Processing Technology","volume":"347 ","pages":"Article 119150"},"PeriodicalIF":7.5,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145577372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Laser ablation and surface modification-assisted polishing of polycrystalline diamond: From mechanisms of ablation and phase transition to high-efficiency processing","authors":"Qixian Zhang ,&nbsp;Rui Gao ,&nbsp;Changning Bai ,&nbsp;Kangsen Li ,&nbsp;Rui Chen ,&nbsp;Yan Bao ,&nbsp;Song Yuan ,&nbsp;Chi Fai Cheung ,&nbsp;Zhigang Dong ,&nbsp;Chunjin Wang","doi":"10.1016/j.jmatprotec.2025.119159","DOIUrl":"10.1016/j.jmatprotec.2025.119159","url":null,"abstract":"<div><div>Polycrystalline diamond (PCD) exhibits exceptional thermal and electronic properties, making it a critical material for high-power and high-performance electronic devices. However, its extreme hardness, chemical inertness, and variable grain orientation pose significant challenges to efficient polishing. To address this issue, this study proposes a laser ablation and surface modification-assisted polishing method, based on a combined high-fluence and low-fluence laser scanning strategy. The influence of laser parameters on surface morphology and phase composition is systematically investigated, and the effectiveness of the hybrid process is comprehensively validated. The results demonstrate that high-fluence vertical-incidence laser ablation significantly reduces surface roughness through a self-planarization mechanism, arising from the laser energy modulation by surface topography and the material’s intrinsic brittleness. The subsequent low-fluence laser scanning induces substantial phase transitions under combined thermal and stress effects, resulting in a modified layer with reduced hardness and enhanced plastic deformation capacity. In the final mechanical polishing stage, the surface with the combined laser scanning strategy achieves a roughness of 0.33 μm after 60 min of polishing. The maximum material removal rate reaches 24.7 μm/h, which is 2.1 times that of the pristine sample. This is attributed to the synergistic effect of laser-induced planarization and surface modification in enhancing polishing performance. These findings offer valuable insights into the interaction between laser radiation and diamond materials, and present a promising hybrid strategy for high-efficiency PCD processing.</div></div>","PeriodicalId":367,"journal":{"name":"Journal of Materials Processing Technology","volume":"347 ","pages":"Article 119159"},"PeriodicalIF":7.5,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145620997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Atomistic insights into ultrafast phase transitions driving nanoparticle formation in femtosecond laser–irradiated nickel-based superalloys","authors":"Zhicheng Chen ,&nbsp;Jingya Sun ,&nbsp;Gen Lin ,&nbsp;Ziqi Ding ,&nbsp;Yang Ding ,&nbsp;Lan Jiang","doi":"10.1016/j.jmatprotec.2025.119145","DOIUrl":"10.1016/j.jmatprotec.2025.119145","url":null,"abstract":"<div><div>Femtosecond laser machining of specialty alloys has evolved into a high-precision, low-damage technology with extensive applications in micro- and nano-scale fabrication. However, the lack of atomic-scale underlying mechanisms significantly hinders the efficiency of process optimization. This study investigated the electron dynamics and ultrafast phase transitions of nickel-based superalloys at the atomic level using pump–probe microscopy and molecular dynamics coupled with the two-temperature model (MD-TTM). Within the first 2 ps, electron excitation and scattering increased the transient differential reflectivity (TR). Beyond this timescale, the onset of mechanical relaxation and phase transitions in lattice system decreased the TR. Spatiotemporal analysis of TR micrographs identified thresholds for spallation and phase explosion and confirmed the coexistence of these two-phase transition mechanisms. The experimental observations were further demonstrated by atomic-scale insights from MD-TTM simulations, which capture the evolution of electron–lattice energy transfer, lattice density variations and, material ejection dynamics. Based on the identified mechanisms, the morphology of both the ejected materials and the processed surface can be tuned by precisely adjusting the laser fluence. This study offers fundamental insights into the complex ultrafast processes governing femtosecond laser–alloy interactions and establishes a theoretical foundation for material ejection and surface morphology regulation, enabling high-precision micro/nanostructure fabrication.</div></div>","PeriodicalId":367,"journal":{"name":"Journal of Materials Processing Technology","volume":"347 ","pages":"Article 119145"},"PeriodicalIF":7.5,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145577321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chemomechanical synergy in cobalt polishing: Non-destructive removal via atomic force microscopy at atomic levels","authors":"Fangjin Xie,&nbsp;Min Zhong,&nbsp;Xiaobing Li,&nbsp;Meirong Yi,&nbsp;Jianfeng Chen,&nbsp;Wenhu Xu","doi":"10.1016/j.jmatprotec.2025.119144","DOIUrl":"10.1016/j.jmatprotec.2025.119144","url":null,"abstract":"<div><div>With the advancement of integrated circuit (IC) technology, cobalt (Co) has garnered significant attention as a promising interconnect metal. However, challenges persist in its application to chemical mechanical polishing (CMP). This study investigated the chemomechanical synergy between liquid environments and oxidizers on Co surfaces using atomic force microscopy (AFM). Three environments, including deionized (DI) water, anhydrous ethanol, and air, were employed, along with three common oxidizers (H₂O₂, K₂S₂O₈, and KIO₄). Results demonstrate that DI water substantially enhances the chemomechanical synergistic effect, particularly under high downforce conditions, where both scratch depth and width significantly increase. In contrast, air and anhydrous ethanol environments predominantly rely on mechanical action, yielding weaker material removal. Among the oxidizers, KIO₄ exhibits the strongest oxidative capability. It generates a dense oxide layer that optimizes chemomechanical synergy, improves scratch efficiency, and enables non-destructive material removal. Conversely, H₂O₂ and K₂S₂O₈ inhibit scratch effectiveness due to inhomogeneous oxide layer formation. Multiscale characterization reveals the influence of oxidizers on the chemical composition, microstructural morphology, and distribution characteristics of oxide layers on Co surface. This study provides theoretical foundations for optimizing Co CMP processes.</div></div>","PeriodicalId":367,"journal":{"name":"Journal of Materials Processing Technology","volume":"347 ","pages":"Article 119144"},"PeriodicalIF":7.5,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145527652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synergistic enhancement of strength-toughness of TiAl/Ti₂AlNb diffusion bonding joint via high-energy electropulsing treatment","authors":"Yu Peng ,&nbsp;Lei Zhu ,&nbsp;Li Feng ,&nbsp;Yifan Zhang ,&nbsp;Zhengxin Feng ,&nbsp;Juntao Zou ,&nbsp;Beibei Wei ,&nbsp;Kaidi Li ,&nbsp;Bin Tang ,&nbsp;Jinshan Li","doi":"10.1016/j.jmatprotec.2025.119141","DOIUrl":"10.1016/j.jmatprotec.2025.119141","url":null,"abstract":"<div><div>The new-generation turbine structure, using TiAl alloy for blades and Ti₂AlNb alloy for the disk significantly enhances the thrust-to-weight ratio and efficiency of aero-engines. The turbine blades are often attached to the disk using advanced welding technologies. However, brittle intermetallic compounds (IMCs) and residual stresses tend to form after welding, impairing the performance of TiAl/Ti₂AlNb joints. In this study, the high-energy electropulsing treatment (HEEPT) was introduced to optimise the interfacial microstructures and properties, of TiAl/Ti₂AlNb joints, substantially improving the efficiency of post-bonding heat treatment. The observed average tensile strength and elongation of TiAl/Ti₂AlNb joints reached 470.93 MPa and 0.353 %, respectively, after 1 min of HEEPT, representing increases of 41.3 % in tensile strength and 99.4 % in elongation compared with those of the joints formed via diffusion bonding (DB). This enhancement is mainly attributed to the combined effects of the thermal and electron wind effects of HEEPT, which prevent the formation of continuous brittle IMCs of AlNb₂ at the bonding interface. Additionally, the interfacial β₀/B2 phase and equiaxed α₂ phase form a soft and hard combination configuration, producing anisotropic strengthening due to deformation-induced stress. Notably, HEEPT induces the precipitation of nanoscale acicular α₂ from equiaxed α phase. Additionally, HEEPT promotes the uniform arrangement of nanoscale acicular ω from β₀/B2 phase at the bonding interface, thereby achieving a synergistic enhancement of strength and toughness. This efficient HEEPT provides a novel strategy to strengthen other dissimilar weld joints and offers a sustainable alternative to traditional heat treatment.</div></div>","PeriodicalId":367,"journal":{"name":"Journal of Materials Processing Technology","volume":"347 ","pages":"Article 119141"},"PeriodicalIF":7.5,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145527654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-power laser-arc hybrid additive manufacturing of aluminum alloys: Resolving the conflict between forming precision and keyhole-induced porosity via beam oscillation","authors":"Heziqi Liu ,&nbsp;Lianyong Xu ,&nbsp;Kangda Hao ,&nbsp;Yongdian Han ,&nbsp;Lei Zhao ,&nbsp;Wenjing Ren","doi":"10.1016/j.jmatprotec.2025.119146","DOIUrl":"10.1016/j.jmatprotec.2025.119146","url":null,"abstract":"<div><div>In laser-arc hybrid additive manufacturing (LAHAM), the high-power laser required for precise forming often leads to unstable keyhole behavior and severe keyhole-induced porosity, which compromise mechanical properties. In this study, laser beam oscillation was employed to address this contradiction. It was found that laser beam oscillation could distribute the laser energy over a larger area, reducing the average power density below the critical threshold for keyhole formation. Under high-power laser processing (laser power of 3 kW), optimizing the oscillation parameters decreased the keyhole-induced porosity from 16.3 % under the non-oscillating condition to 0.3 %, and restored the elongation from 2.2 % to 17.4 %. Moreover, the high-power laser with beam oscillation preserved the precision-forming benefits. The highly ionized plasma generated by the laser provided a low-resistance channel for the arc current, which attracted and compressed the arc. The resulting electromagnetic forces guided the droplets along a more controlled transfer path, and together with the stabilized molten pool behavior, enabled superior forming accuracy. Compared with the low-power (laser power of 1 kW) samples, the surface roughness was reduced by 68.2 %, and the material utilization increased by 29.4 %. In addition, the high-power oscillating laser promoted molten flow to disrupt dendrites, facilitated rapid crystallization, and reduced local temperature gradients, thereby breaking the directional growth of columnar grains. The resulting refined, random-oriented multimodal grain structure significantly reduced mechanical anisotropy. This work provides a feasible technical pathway and a valuable reference for achieving high-quality additive manufacturing of aluminum and other challenging materials.</div></div>","PeriodicalId":367,"journal":{"name":"Journal of Materials Processing Technology","volume":"347 ","pages":"Article 119146"},"PeriodicalIF":7.5,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145527655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heat input regulation for geometric and property control in directed energy deposition with dense scan path strategy","authors":"Zhiyu Ye ,&nbsp;Binghua Lv ,&nbsp;Rui Li ,&nbsp;Mingzhi Chen ,&nbsp;Zhandong Wang ,&nbsp;Guifang Sun ,&nbsp;En-Hou Han","doi":"10.1016/j.jmatprotec.2025.119138","DOIUrl":"10.1016/j.jmatprotec.2025.119138","url":null,"abstract":"<div><div>A fundamental challenge in manufacturing high-performance components using directed energy deposition (DED) is the effective management of heat accumulation when processing complex geometries with a high infill density zigzag scanning strategy. This study reveals an inherent conflict between local and global thermal effects that unresolved by constant power strategies: high power intensifies local melt pool instability at path turning points, whereas low power causes more severe global heat accumulation and sacrifices forming accuracy due to an increased layer count. The study establishes a dual heat-affected zone (HAZ) gradient evolution model at the DED-HIP interface, and reveals the embrittlement risk of the dissolution heat-affected zone (D-HAZ) under high heat input and the softening mechanism of the over-aged HAZ (OA-HAZ). Therefore, this study proposes a power closed-loop control (PCLC) strategy based on real-time melt pool width monitoring to achieve active thermal management. It is revealed that the PCLC technology, by precisely suppressing local overheating in the zigzag scanning path, achieves a synergistic optimization of morphology, accuracy, and microstructure, with significantly enhanced mechanical properties (elongation reached 21.15 %, and tensile strength reached 1189 MPa, achieving 95.8 % that of the substrate). This research provides crucial theoretical guidance and technical support for the additive manufacturing of high-performance components requiring customized microstructures and precise geometric control, such as aero-engine integral blisks.</div></div>","PeriodicalId":367,"journal":{"name":"Journal of Materials Processing Technology","volume":"347 ","pages":"Article 119138"},"PeriodicalIF":7.5,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145527658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}