Journal of Materials Science最新文献

{"title":"Poly(vinyl chloride) (PVC): an updated review of its properties, polymerization, modification, recycling, and applications","authors":"Great Iruoghene Edo,&nbsp;Winifred Ndudi,&nbsp;Ali B. M. Ali,&nbsp;Emad Yousif,&nbsp;Khalid Zainulabdeen,&nbsp;Priscillia Nkem Onyibe,&nbsp;Helen Avuokerie Ekokotu,&nbsp;Endurance Fegor Isoje,&nbsp;Ufuoma Augustina Igbuku,&nbsp;Arthur Efeoghene Athan Essaghah,&nbsp;Dina S. Ahmed,&nbsp;Huzaifa Umar,&nbsp;Dilber Uzun Ozsahin","doi":"10.1007/s10853-024-10471-4","DOIUrl":"10.1007/s10853-024-10471-4","url":null,"abstract":"<div><p>Poly(vinyl chloride) (PVC) has been a fascinating subject for polymer science research. Its characteristics are heightened by its inherent structural faults resulting from direct manufacturing (by free-radical polymerization), which also cause its thermal instability. Some of the fundamental limiting features of PVC have been suggested to be alleviated by improved chemistry during PVC synthesis, in addition to the use of both inorganic and organic thermal stabilizers. The characteristics, characterization, modification, recycling, and various applications of PVC are all examined in this paper along with the past and most recent research discoveries. It has been suggested that some of the fundamental limiting properties of PVC can be lessened by applying both inorganic and organic thermal stabilizers in conjunction with improved chemistry during PVC manufacture. Numerous ongoing studies have expanded this chemistry, primarily through the chemical changes of this polymeric substance. The chemical modification of PVC employing various materials as an active modifying agent is described in this work. The latter comprised grafting polymerizations, nucleophilic radicals, substitutions, PVC modifications, and removal or dehydrochlorination. This perspective addresses the main PVC reactivity trends and provides an overview of PVC functionalization while examining the environmental implications of PVC via the prism of chemical recycling. Through extensive ongoing research, this chemistry has been expanded, primarily through the chemical changes of this polymeric substance. To improve its photo-stability properties, expand the applications of poly(vinyl chloride) (PVC), and investigate PVC-related phenomena, numerous chemical modifications have been introduced to PVC.</p><h3>Graphical abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":645,"journal":{"name":"Journal of Materials Science","volume":"59 47","pages":"21605 - 21648"},"PeriodicalIF":3.5,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142789314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Replacing plastic automotive interiors with bamboo: a study on the mechanical and flame-retardant properties of melamine polyphosphate-modified bamboo fiber-reinforced composites","authors":"Yinxuan Li,&nbsp;Zhitong Yuan,&nbsp;Mingpeng Li,&nbsp;Shaohua Gu,&nbsp;Cuicui Wang,&nbsp;Haitao Cheng","doi":"10.1007/s10853-024-10227-0","DOIUrl":"10.1007/s10853-024-10227-0","url":null,"abstract":"<div><p>Bamboo fiber-reinforced composites, noted for their light weight, have seen application in automotive interior components. However, their flammability presents significant risks to vehicular safety. In this study, melamine polyphosphate (MPP) was used to flame-retardant modify bamboo flour (BF) reinforced polypropylene (PP)/ poly (lactic acid) (PLA) composites. The results showed that MPP are contribute to enhancing the thermal stability and improving the flame retardancy of composites. Notably, the peak of heat release rate (629.66 kW/m²) of BF reinforced PP/PLA composites containing 5% MPP was reduced by 35.23% compared to unmodified composites (972.09 kW/m²). Besides, compared with other composites, composites containing 5% MPP constituted the lowest fire hazard. In terms of mechanics, it is notable that MPP could significantly enhance the flexural and tensile moduli of the composites. Meanwhile, composites containing 5% MPP yielded the optimal flexural strength (41.52 MPa) and tensile strength (53.79 MPa). These results suggest that MPP is a viable candidate for flame-retardant modification of BF reinforced PP/PLA composites, offering potential for use in automotive interior components.</p><h3>Graphical abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":645,"journal":{"name":"Journal of Materials Science","volume":"59 47","pages":"21721 - 21734"},"PeriodicalIF":3.5,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142789284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Extremely long Ag nanowires synthesis and electromechanical characterization for transparent, flexible, stretchable electrode","authors":"Hyojin An,&nbsp;Nam Woon Kim,&nbsp;Kungshik Kim,&nbsp;Byeong-Kwon Ju,&nbsp;Shin Hur","doi":"10.1007/s10853-024-10356-6","DOIUrl":"10.1007/s10853-024-10356-6","url":null,"abstract":"<div><p>The performance of Ag nanowire (NW) electrodes can be improved by reducing contact junction resistance between NWs during the post-treatment. Thin and long Ag NWs simplify this process by reducing the number of contact junctions, thereby enhancing performance. Through the polyol method with slow-dropwise addition of AgNO₃, we synthesized Ag NWs with an average length of 480 µm, an average diameter of 150 nm, and an aspect ratio of 3,200. Using these long Ag NWs (L-Ag NWs), we fabricated a flexible transparent electrode with high transmittance (92.16%) and low sheet resistance (20 ohms/sq). After 100,000 bending tests, the resistance change was extremely stable (&lt; 0.002). A stretchable transparent electrode was fabricated and subjected to a 1,600-cycle stretching test at 20% strain. The L-Ag NW electrode exhibited better optoelectrical properties than the short-Ag NW (S–Ag NW). The development of L-Ag NWs has the potential to revolutionize the fabrication of wearable sensors and transparent electrode materials.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":645,"journal":{"name":"Journal of Materials Science","volume":"59 47","pages":"21817 - 21827"},"PeriodicalIF":3.5,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10853-024-10356-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142789282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Difference between thermal-induced martensite and deformation-induced martensite in 304 austenitic stainless steel","authors":"Xin Liu,&nbsp;Yanhui Guo,&nbsp;Yuexiang Wang,&nbsp;Linghuan Pang,&nbsp;Bin Fu","doi":"10.1007/s10853-024-10476-z","DOIUrl":"10.1007/s10853-024-10476-z","url":null,"abstract":"<div><p>This study investigates the differences between deformation-induced martensite (DIM) and thermal-induced martensite (TIM) in 304 austenitic stainless steel, focusing on their formation, distribution, and behavior during annealing. DIM was generated through cold rolling (CR), while TIM was produced via cryogenic treatment (CT). Microstructural characterization revealed that both martensite’s are distributed in blocky forms, with DIM exhibiting a finer grain structure compared to TIM. During the annealing process, both types of martensite undergo reverse transformations back to austenite, but DIM begins to reverse earlier at a slower rate. Consequently, after annealing, DIM yields a higher amount of reversed austenite (RA) with smaller grain size, whereas TIM transforms into fewer but larger RA grains. This study provides critical insights into the distinct phase transformation mechanisms of DIM and TIM, offering a deeper understanding of their effects on the microstructure and mechanical properties of 304 austenitic stainless steel. This knowledge is valuable for optimizing processing techniques and enhancing material performance in industrial applications.</p><h3>Graphical abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":645,"journal":{"name":"Journal of Materials Science","volume":"59 47","pages":"21974 - 21986"},"PeriodicalIF":3.5,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142789280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An experimental investigation on the influence of weave architectures on out-of-plane and in-plane impact properties of 3D woven fabric-reinforced composites","authors":"Soumya Chowdhury,&nbsp;Dushyant Dubey,&nbsp;Bijoya Kumar Behera","doi":"10.1007/s10853-024-10466-1","DOIUrl":"10.1007/s10853-024-10466-1","url":null,"abstract":"<div><p>3D woven fabric-reinforced composites (3DWFRCs) offer excellent structural integrity, impact resilience, and strength-to-weight ratios, making them ideal for advanced lightweight engineering applications. The purpose of this research is to investigate the effects of binder yarn pathways, stuffer–binder ratios, and inter-yarn cross-overs on out-of-plane and in-plane impact responses under low-velocity conditions in six different 3D weave structures with a consistent areal density. This study investigated the out-of-plane impact properties of 3DWFRCs across 16–50 J energies, revealing how weave architectures affect damage tolerance, including rebound, penetration, and perforation thresholds. The orthogonal matt 3×3 (4SLORMT3) weave, with the fewest inter-yarn cross-over points, demonstrated superior low-velocity impact performance, highlighting the crucial role of nonlinear inter-yarn friction dynamics in enhancing composite impact resistance. A parallel trend was observed in the through-thickness angle-interlock weave structures, with 4SLANTW (angle-interlock twill 3×3) outperforming 4SLANPL (angle-interlock plain 1×1), attributed to its elongated binder yarn float length and fewer inter-yarn cross-over points. An X-ray micro-computed tomography scan was used for non-destructive testing to measure impact toughness and demonstrate the extent of damage resulting from a projectile impact at 3.14 m/s. Furthermore, compression-after-Impact tests were carried out on those perforated specimens, to provide a comprehensive evaluation of their damage tolerance. When subjected to a pendulum impact at 3.54 m/s and 11 J, the 4SLORPL weave, which has 350 inter-yarn cross-over points, exhibits exceptional resistance to edgewise impact force. This is attributed to the heightened inter-yarn friction, which accentuates energy dissipation and facilitates effective stress distribution.</p><h3>Graphical abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":645,"journal":{"name":"Journal of Materials Science","volume":"59 47","pages":"21735 - 21800"},"PeriodicalIF":3.5,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142789313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"NiO-decorated cocoon silk-derived carbon-based non-invasive electrochemical sensor for detecting glucose in saliva","authors":"Hongteng Zhang,&nbsp;Jingwen Yin,&nbsp;Yue Wang,&nbsp;Yasushi Hasebe,&nbsp;Zhiqiang Zhang","doi":"10.1007/s10853-024-10478-x","DOIUrl":"10.1007/s10853-024-10478-x","url":null,"abstract":"<div><p>To enhance the quality of life for individuals with diabetes, groundbreaking researches for non-invasive sensors were devised, capable of monitoring glucose levels in saliva. Herein, cocoon silk was first pyrolyzed and acid-treated, following by the decoration of NiO nanoparticles under calcination method. The activated carbon exhibits excellent electrocatalytic properties owing to the inherent presence of heteroatoms within the cocoon silk, specifically nitrogen and oxygen. The synergetic effect of NiO nanoparticles and cocoon silk-based carbons improves the electron transfer rate and enhances the electrocatalytic activity toward the detection of glucose. This enzyme-free glucose sensor shows the sensitivity of 74.24 μA mM⁻¹ cm⁻², the wide linear range from 1 to 3300 μM, and the low detection limit of 0.28 μM. Furthermore, the sensor demonstrates good selectivity, repeatability, and stability. Importantly, it is able to detect the glucose levels in real human saliva without pretreatment, exhibiting great potentials in the application of non-invasive sensors.</p></div>","PeriodicalId":645,"journal":{"name":"Journal of Materials Science","volume":"59 47","pages":"21868 - 21881"},"PeriodicalIF":3.5,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142789283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A review on the recent progress on photodetectors","authors":"Xiaojuan Lian,&nbsp;Limeng Luo,&nbsp;Minghao Dong,&nbsp;Ziyan Miao,&nbsp;Xi Qi,&nbsp;Zhikuang Cai,&nbsp;Lei Wang","doi":"10.1007/s10853-024-09959-w","DOIUrl":"10.1007/s10853-024-09959-w","url":null,"abstract":"<div><p>Photodetectors play a pivotal role in modern technology, particularly in applications requiring precise light detection and imaging. Traditional photodetectors, however, are often constrained by their fixed wavelength ranges, making them inadequate for multi-band detection needs. To address this limitation, phase change materials (PCMs) have emerged as a promising solution. PCMs are notable for their high sensitivity, rapid response times, and their capacity to detect a broad spectrum of wavelengths. These materials can transition between crystalline and amorphous states, allowing real-time adjustment of the detection wavelength. Furthermore, integrating surface plasmon resonance with photodetectors significantly enhances their performance by boosting light absorption and signal strength. This review delves into the fundamental principles, benefits, and challenges of various types of photodetectors. It specifically highlights traditional photodetectors, plasmon-enhanced photodetectors, and recent advancements in PCM-based photodetectors. By examining these innovations, we aim to provide valuable insights that could shape the future development and application of photodetector technology, ensuring they meet the evolving demands of various technological fields.</p></div>","PeriodicalId":645,"journal":{"name":"Journal of Materials Science","volume":"59 47","pages":"21581 - 21604"},"PeriodicalIF":3.5,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142789316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Highly dispersed Pd nanoclusters anchored on CNx-modified SiO2 for selective hydrogenation of nitrile-butadiene rubber","authors":"Kewen Zhang,&nbsp;Benwei Fan,&nbsp;Shidong Wang,&nbsp;Hongwei Zhang,&nbsp;Qunhong Liu,&nbsp;Xiaojun Bao,&nbsp;Pei Yuan","doi":"10.1007/s10853-024-10444-7","DOIUrl":"10.1007/s10853-024-10444-7","url":null,"abstract":"<div><p>Heterogeneous hydrogenation is an effective way to improve the performance of unsaturated polymers, but the preparation of supported catalysts with high metal dispersion and stability remains challenging. Herein, we synthesize a SiO₂-based support wrapping with carbon nitride on the surface (CN_<i>x</i>@SiO₂) via the thermal polycondensation of melamine, on which Pd nanoclusters with highly exposed active sites are formed and stably anchored via the strong interaction between N and Pd. The thermal temperature affects the properties of CN_<i>x</i>, which further modulates the electronic and structural state of Pd nanoclusters. The Pd/CN_<i>x</i> @SiO₂-500 catalyst, prepared at 500 °C with an optimal CN_<i>x</i> structure (<i>g</i>-C₃N₄) and high nitrogen content, features highly dispersed and electron-rich Pd nanoclusters (1.3 nm). This catalyst exhibits a hydrogenation activity of 98.0% for nitrile rubber, with a selectivity of 100% for C=C bonds. This work provides a facile method to prepare Pd catalysts with high activity and stability, paving the way for the upgrading of unsaturated polymers via hydrogenation.</p><h3>Graphical abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":645,"journal":{"name":"Journal of Materials Science","volume":"59 46","pages":"21265 - 21276"},"PeriodicalIF":3.5,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142753908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On enhancing the creep performance of modified 9Cr-1Mo steel by employing a secondary short-term heat treatment","authors":"Amey Parnaik,&nbsp;A. H. V. Pavan,&nbsp;A. Das,&nbsp;O. G. Klimova-Korsmik,&nbsp;M. O. Gushchina,&nbsp;Kai Chen,&nbsp;R. L. Narayan","doi":"10.1007/s10853-024-10439-4","DOIUrl":"10.1007/s10853-024-10439-4","url":null,"abstract":"<div><p>Creep behavior of an as-received, normalized, and tempered 9Cr-1Mo (P 91) steel and its secondary short-term normalized and short-term tempered counterpart at temperatures of 550 °C, 600 °C, and 650 °C, at stresses in the range of 80–260 MPa, has been studied. The secondary heat treatment leads to insignificant coarsening of the prior austenite grains but refines the martensitic lath sub-grains and the grain boundary M₂₃C₆ carbides and enhances the dislocation density compared to that of the as-received alloy. Tensile creep tests reveal that the creep life of the secondary heat-treated alloy is several folds higher than that of the as-received alloy. For both alloys, considering the effect of threshold stresses at different temperatures, an effective stress exponent <i>n</i>_eff of 4.5–5.5, and activation energies of 316.4 and 258.3 KJ mol⁻¹, it indicates that the steady-state creep relaxation mechanism involves dislocation climb and annihilation. Microstructural characterization, before and after the creep tests, reveals that lath sub-grains and M₂₃C₆ precipitates in both alloys undergo significant coarsening, with the former leading to microstructural instability at the onset of the tertiary stage of creep. Deformation mechanisms in the steady-state regime are described as a balance between processes that impede and facilitate dislocation motion in the sub-grain interior. The interplay between energy minimization-induced sub-grain coarsening and Zener pinning of the boundaries by M₂₃C₆ is discussed in the context of microstructural instability-induced failure.</p></div>","PeriodicalId":645,"journal":{"name":"Journal of Materials Science","volume":"59 46","pages":"21494 - 21514"},"PeriodicalIF":3.5,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142754345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dual hydrophilic/hydrophobic SiO2 transparent super-hydrophobic coating with good interfacial adhesion and high mechanical robustness","authors":"Qing Wu,&nbsp;Renjie Yao,&nbsp;Dong Guo,&nbsp;Yanyang Lei,&nbsp;Jingqi Sun,&nbsp;Yating Li,&nbsp;Dan Jin,&nbsp;Jianfeng Zhu,&nbsp;Hongjie Luo","doi":"10.1007/s10853-024-10470-5","DOIUrl":"10.1007/s10853-024-10470-5","url":null,"abstract":"<div><p>Water is identified as the main culprit of damage for sandstone cultural relics because of their porous intrinsic structure and nature-exposed feature. Thus, developing a super-hydrophobic coating, simultaneously with transparency, good interfacial adhesion, and robust mechanical properties, is especially critical for long-term application. However, the difficulty of balancing the contradictions between various performances is a tricky issue. Herein, tiny-level addition of amino-modified SiO₂ was used to promote the dispersibility of fluorinated SiO₂ in super-hydrophobic coating via the attachment of amino groups that was able to form hydrogen-bonding interactions, also contributing to the improved interfacial adhesion between coating and sandstone substrate. Moreover, when mass ratio of amino-modified SiO₂ to fluorinated SiO₂ reaches 1:100, the coating provides the best transparency, the optimal resistances to tape peeling, sandpaper abrasion, sand and rainwater impactions, superior than coating with perfluorinated SiO₂ particles. This mainly associates with the construction of uniform and small undulating rough surface that increases water repellency and reduces light scattering, as well as the formation of stable skeleton of “rigid-flexible” SiO₂/polydimethylsiloxane that transfers stress and dissipates energy effectively. The simple and effective strategy well solves the performance conflict and has the potential to be applied in large scale for protection of sandstone cultural relics.</p><h3>Graphical abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":645,"journal":{"name":"Journal of Materials Science","volume":"59 46","pages":"21294 - 21309"},"PeriodicalIF":3.5,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142753907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}