Powder Technology最新文献_第6页

Correlation between particle size, secondary dendrite arm spacing, and local cooling rate in gas-atomized stainless steel powders for additive manufacturing 增材制造用气雾化不锈钢粉末中粒径、二次枝晶臂间距和局部冷却速率的关系

IF 4.5 2区工程技术

Powder Technology Pub Date : 2025-05-06 DOI: 10.1016/j.powtec.2025.121096

Matheus Roberto Bellé, Anastasiia Sherstneva, Michael Hauser, Marco Wendler, Olena Volkova

{"title":"Correlation between particle size, secondary dendrite arm spacing, and local cooling rate in gas-atomized stainless steel powders for additive manufacturing","authors":"Matheus Roberto Bellé, Anastasiia Sherstneva, Michael Hauser, Marco Wendler, Olena Volkova","doi":"10.1016/j.powtec.2025.121096","DOIUrl":"10.1016/j.powtec.2025.121096","url":null,"abstract":"<div><div>Additive manufacturing (AM) demands metallic powders with controlled microstructure and morphology to ensure high-performance components, especially in processes like Laser Powder Bed Fusion (PBF-LB). Gas atomization techniques such as Vacuum Inert Gas Atomization (VIGA) and Electrode Inert Gas Atomization (EIGA) are widely employed for producing stainless steel powders tailored for AM applications. In this study, the solidification behavior of such powders is investigated by analyzing the secondary dendrite arm spacing (SDAS) as a function of particle size (15–170 μm). SDAS is used as a microstructural indicator to estimate local cooling rates during atomization. Experimental results reveal that SDAS increases linearly for particles ≤100 μm and exponentially for larger particles, independent of steel composition, atomization gas, or method. Derived cooling rates, ranging from 10<sup>4</sup> to 10<sup>7</sup> K s<sup>−1</sup>, closely align with predictions from dimensionless criteria, affirming the relevance of such models under rapid solidification. Conversely, regressions developed for slower cooling conditions underestimate these values, emphasizing the need for high-fidelity models in atomization contexts. Notably, fine powders (< 25 μm) showed evidence of metastable δ-ferrite formation due to ultrafast cooling, as confirmed by magnetic saturation and XRD analyses. This work strengthens the predictive control of powder solidification behavior, aiding in the design of high-performance AM components.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"461 ","pages":"Article 121096"},"PeriodicalIF":4.5,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143942766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Development of a sustainable engineered geopolymer composite with mitigated autogenous shrinkage, enhanced mechanical performance, and improved thermal behaviour by recycled concrete powder 开发一种可持续工程地聚合物复合材料，通过再生混凝土粉末减轻自收缩，增强机械性能和改善热行为

IF 4.5 2区工程技术

Powder Technology Pub Date : 2025-05-03 DOI: 10.1016/j.powtec.2025.121087

Yuekai Xie , Yingying Guo , Jianfeng Xue

{"title":"Development of a sustainable engineered geopolymer composite with mitigated autogenous shrinkage, enhanced mechanical performance, and improved thermal behaviour by recycled concrete powder","authors":"Yuekai Xie , Yingying Guo , Jianfeng Xue","doi":"10.1016/j.powtec.2025.121087","DOIUrl":"10.1016/j.powtec.2025.121087","url":null,"abstract":"<div><div>The application of recycled concrete powder (RCP) into engineered geopolymer composites (EGC) could be a sustainable alternative to decreasing the carbon footprint and improving the mechanical properties of EGC. This paper evaluated the mechanical properties, autogenous shrinkage, thermal resistance, and microstructures of RCP-EGC. The results indicated that the replacement of natural sand (NS) with RCP decreased the autogenous shrinkage of RCP-EGC by up to 19.1 %. With partial replacement of NS with RCP (75 %), the compressive strength was increased from 66.6 to 77.7 MPa and slightly decreased to 76.8 MPa with complete replacement. The 100 % replacement of NS with RCP increased the tensile strength and strain capacity from 4.93 to 6.25 MPa, and 9.26 % to 11.14 %, respectively. The improvement in the mechanical behaviour was attributed to the enhanced gel formation, as can be verified by the microstructural results. After thermal exposure to 60 and 120 °C, RCP-EGC with 100 % RCP exhibited enhanced compressive strength (87.4 MPa), tensile strength (7.18 MPa), and strain capacity of (10.44 %), higher than those without RCP (73.3 MPa, 5.45 MPa, and 8.15 %). For the samples exposed to 180 °C, the strain-hardening behaviour could not be determined. The RCP-EGC exhibited higher compressive strength after the higher thermal exposure of 180, 300 and 400 °C. The results from carbon footprint calculation and cost-effectiveness analysis suggested replacing NS with RCP can be an environmentally friendly and economically affordable alternative to improving the behaviour of EGC at ambient and elevated temperatures.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"460 ","pages":"Article 121087"},"PeriodicalIF":4.5,"publicationDate":"2025-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143916299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Comparison of granules obtained with two twin-screw granulators of different diameter working at the same shear rate 不同直径双螺杆造粒机在相同剪切速率下所制粒的比较

IF 4.5 2区工程技术

Powder Technology Pub Date : 2025-05-02 DOI: 10.1016/j.powtec.2025.121092

Nazareth E. Ceschan , María C. Balbi , Pablo Ravazzoli , German Drazer , Fernando Muzzio , Gerardo Callegari

{"title":"Comparison of granules obtained with two twin-screw granulators of different diameter working at the same shear rate","authors":"Nazareth E. Ceschan , María C. Balbi , Pablo Ravazzoli , German Drazer , Fernando Muzzio , Gerardo Callegari","doi":"10.1016/j.powtec.2025.121092","DOIUrl":"10.1016/j.powtec.2025.121092","url":null,"abstract":"<div><div>We study the response of two twin-screw granulators of different barrel diameter to the variation of three process parameters (liquid-to-solid ratio, screw speed and throughput), while maintaining the same shear rate field along the screws. Various responses, including size distribution, porosity and content uniformity, were measured to determine granule characteristics. The set of experiments was based on a central composite design face-centered. Granules in both systems showed drug content consistent with expected values across varying process parameters. Relative granules size, normalized with the granulator gap, was larger for the equipment with the smaller gap. The liquid-to-solid ratio (LSR) was the most influential parameter affecting the granule size. Specifically, granule size increased with LSR values in both systems, consistent with previous studies. Elevated LSR values resulted in greater amounts of over-granulated material, whereas lower values produced exceedingly small (fines) or under-granulated material. The minimum amounts of both over- and under-granulated material were found at intermediate LSR values. Porosity varied differently between the systems, with a consistent reduction observed as LSR increased from 0.3 to 0.4. Optimization studies revealed that central values of LSR and screw speed minimized fines and bigger granules while maximizing porosity, critical attributes for downstream processing. Granule size and porosity exhibited no significant correlation with tablet tensile strength across both systems. These findings offer valuable insights for optimizing pharmaceutical manufacturing processes to enhance product quality.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"462 ","pages":"Article 121092"},"PeriodicalIF":4.5,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144105744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Computational investigation of roasting characteristics of zinc sulfide concentrate in an industrial-scale 123 m2 fluidizing furnace 工业规模123 m2流化炉硫化锌精矿焙烧特性的计算研究

IF 4.5 2区工程技术

Powder Technology Pub Date : 2025-05-02 DOI: 10.1016/j.powtec.2025.121091

Feixue Sun, Guanqing Wang, Shuliu Yang, Shiliang Yang

{"title":"Computational investigation of roasting characteristics of zinc sulfide concentrate in an industrial-scale 123 m2 fluidizing furnace","authors":"Feixue Sun, Guanqing Wang, Shuliu Yang, Shiliang Yang","doi":"10.1016/j.powtec.2025.121091","DOIUrl":"10.1016/j.powtec.2025.121091","url":null,"abstract":"<div><div>Fluidized roasting furnaces are commonly used in the roasting of sulfide ores during the zinc extraction process. However, these furnaces encounter challenges such as fluidization instability, dead zone formation, and abnormal sintering. This study applies the MP-PIC method to analyze the gas-concentrate roasting characteristics in an industrial-scale 123 m<sup>2</sup> fluidized roasting furnace, with model accuracy validated through experimental comparison. The results reveal that particle back-mixing causes the particle velocity near the wall to be significantly lower than that at the center of the furnace, with this effect becoming more pronounced at lower heights. Both gas and particle horizontal velocities are higher in the gas outlet area. The particle velocity in the freeboard region increases with gas flow rate. High particle slip velocities are found near the small gas inlet area at the furnace bottom and close to the bed surface. Meanwhile, the particle temperature above the small gas inlet is markedly lower than that observed above the large gas inlet. Moreover, oxygen concentration rises with the gas flow rate but decreases significantly at higher operating temperatures.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"461 ","pages":"Article 121091"},"PeriodicalIF":4.5,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143937278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Hard/stiff surface coatings for weakening rock particles – Part III: Numerical validation 弱化岩石颗粒用硬/硬表面涂层。第III部分：数值验证

IF 4.5 2区工程技术

Powder Technology Pub Date : 2025-05-02 DOI: 10.1016/j.powtec.2025.121085

Mahmut Camalan

{"title":"Hard/stiff surface coatings for weakening rock particles – Part III: Numerical validation","authors":"Mahmut Camalan","doi":"10.1016/j.powtec.2025.121085","DOIUrl":"10.1016/j.powtec.2025.121085","url":null,"abstract":"<div><div>The size reduction process is an energy-inefficient process for mineral processing, which needs to be remedied. This study uses the Discrete Element Method (DEM) to assess if hard surface coatings on rock particles can weaken them. For that purpose, surface-coated and uncoated particles were generated on the same particle geometry. Then, the impact breakage of both particles was simulated when particles collided with a wall. The simulation results strongly support the hypothesis that strong and/or stiff surface coatings weaken the particles, resulting in higher damage at impact. On the other hand, soft surface coatings are likely to retard the impact breakage of particles. The coated particle that is to be weakened should be relatively strong/stiff so that the generated fragments become finer. High coverage of strong/stiff coatings may be essential if flaky/rectangular particles are to be weakened. There appears to be a limit for the strength/stiffness of the surface coating, above which the particle damage cannot increase further. Introducing a strong or stiff surface coating may even be sufficient to increase particle damage. The simulation results also infer the alternative use of strong and/or stiff surface coatings as grinding aids.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"460 ","pages":"Article 121085"},"PeriodicalIF":4.5,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143908198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Challenging paradigms: The advantages and drawbacks of vertical mills in secondary grinding for iron ore processing 挑战范式：立磨机在铁矿二次磨中的优势与劣势

IF 4.5 2区工程技术

Powder Technology Pub Date : 2025-05-02 DOI: 10.1016/j.powtec.2025.121089

J. Mesquita , Y. Foucaud , R. Belissont , H. Turrer , M. Badawi

引用次数: 0

Exploiting particle-to-particle heat transfer for optical detection of hetero-aggregate aerosols 利用粒子间热传递技术进行异聚集气溶胶的光学检测

IF 4.5 2区工程技术

Powder Technology Pub Date : 2025-05-01 DOI: 10.1016/j.powtec.2025.121080

Felix Luc Ebertz, Torsten Endres, Christof Schulz

{"title":"Exploiting particle-to-particle heat transfer for optical detection of hetero-aggregate aerosols","authors":"Felix Luc Ebertz, Torsten Endres, Christof Schulz","doi":"10.1016/j.powtec.2025.121080","DOIUrl":"10.1016/j.powtec.2025.121080","url":null,"abstract":"<div><div>We present a novel laser-optical in situ method for detecting gas-borne hetero-aggregates and distinguishing them from their individual components. The detection concept utilizes a pump–probe laser scheme, where infrared (IR) absorbing carbon-black (CB) particles are heated upon pump(IR) excitation, and white thermographic phosphor (ZnO:Zn) particles serve as optical markers, providing temperature-sensitive luminescence upon probe ultraviolet (UV) excitation. A temperature-induced spectral red-shift of the centroid of ZnO:Zn luminescence is observed only in hetero-aggregates, where thermal contact enables heat transfer from CB to ZnO:Zn. The method was validated using samples of pristine ZnO:Zn, CB, and pre-prepared hetero-aggregates aerosolized via a dry-powder particle seeder. The temperature sensitivity of the ZnO:Zn luminescence red-shift was determined to be 0.05 nm/K, consistent across pristine and aggregated samples, demonstrating no loss in sensitivity upon hetero-aggregation. The technique successfully discriminates between pump(IR)-heated and cold hetero-aggregates, even at low CB content (2.5 and 4.9 wt%). Varying the delay between pump(IR) and probe(UV) laser pulses revealed a ∼ 35 K maximum temperature increase in ZnO:Zn within the first 140 ns within hetero-aggregates containing 2.5 wt% CB. Doubling the CB content to 4.9 wt% resulted in an increased temperature change at the same laser delay. We observed that probe(UV)-induced heating can influence the temperature measurements in ZnO:Zn/CB aggregates, particularly at UV laser fluences above 0.3 J/cm<sup>2</sup>. However, at lower probe(UV) laser fluences, the UV-induced heating can inherently be minimized.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"460 ","pages":"Article 121080"},"PeriodicalIF":4.5,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143908197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The micro-structure of lactose powder compacts studied by small-angle and ultra small-angle X-ray scattering 采用小角和超小角x射线散射技术研究了乳糖粉末压坯的微观结构

IF 4.5 2区工程技术

Powder Technology Pub Date : 2025-05-01 DOI: 10.1016/j.powtec.2025.121090

Johan Gråsjö , Ann-Sofie Persson , Göran Alderborn , Göran Frenning , Per Hansson , Adrian R. Rennie

{"title":"The micro-structure of lactose powder compacts studied by small-angle and ultra small-angle X-ray scattering","authors":"Johan Gråsjö , Ann-Sofie Persson , Göran Alderborn , Göran Frenning , Per Hansson , Adrian R. Rennie","doi":"10.1016/j.powtec.2025.121090","DOIUrl":"10.1016/j.powtec.2025.121090","url":null,"abstract":"<div><div>The objective was to derive indications of the microstructure of lactose powder compacts was studied by small-angle and ultra small-angle X-ray scattering experiments (SAXS/USAXS). Measurements were performed on a series of lactose powder compacts formed at four different pressures in the interval 300–1000 MPa. Porod analyses of the 1-D scattering profiles, i.e. intensity vs. magnitude of scattering vector (<em>q</em>), enabled accurate determinations of the specific surface area. From these, the interparticle contact area was estimated and compared to the compact tensile strength. Measures of the volume fraction and sizes of the voids were obtained from a fit of a model of polydisperse cylindrical pores. These were found to be approximately disc-shaped, with one dimension significantly smaller than the other two. The scattering data were consistent with an isotropic distribution of pores. The void volume fractions, void sizes and specific surface areas showed anti-correlating trends with the pressure applied.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"460 ","pages":"Article 121090"},"PeriodicalIF":4.5,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143908196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effect of bacterial solution to cementation solution ratio on dust suppression effect of microbial dust suppressant and mechanism analysis 细菌液与胶结液比对微生物抑尘剂抑尘效果的影响及机理分析

IF 4.5 2区工程技术

Powder Technology Pub Date : 2025-05-01 DOI: 10.1016/j.powtec.2025.121086

Yanyun Zhao , Di Zhang , Xiangming Hu , Yue Feng , Jindi Liu , Xiaoniu Yu , Ningjun Jiang

{"title":"Effect of bacterial solution to cementation solution ratio on dust suppression effect of microbial dust suppressant and mechanism analysis","authors":"Yanyun Zhao , Di Zhang , Xiangming Hu , Yue Feng , Jindi Liu , Xiaoniu Yu , Ningjun Jiang","doi":"10.1016/j.powtec.2025.121086","DOIUrl":"10.1016/j.powtec.2025.121086","url":null,"abstract":"<div><div>Dust suppression agent based on Microbially Induced Carbonate Precipitation (MICP) was a new and efficient dust suppression method in recent years, but the environment had a significant impact on its dust suppression effect, and its mechanism of action was complex. This article conducted a dust suppression study by adjusting the volume ratio of bacterial solution and cementation solution in MICP. It was found that the dust suppression efficiency was the highest when the bacterial solution to cementation solution ratio was 2:1, and the wind erosion rate in 15 days was 0.68 %. In the early stage, the nutrients in the bacterial solution bound the coal dust to suppress the dust, but the dominant factor for the continuous performance of the subsequent dust suppression was the deposition and adhesion of CaCO<sub>3</sub> formed by biomineralization. As the reaction progressed, the CaCO<sub>3</sub> crystal form gradually changed from the initial vaterite to calcite. When the proportion of bacterial solution was high, it promoted the convert of crystal form and stabilized the cementation. However, at low bacterial solution proportions, the transformation time of vaterite to calcite was prolonged and the proportion of calcite decreased. The microbial dust suppressant with a high bacterial solution to cementation solution ratio had poor infiltration, causing it to concentrate on the surface of coal dust, resulting in high hardness of the mineralized coal dust consolidation body. At low Bacterial solution to cementation solution ratio, the wettability of the microbial dust suppressant increased, leading to a more uniform consolidation and increased thickness.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"460 ","pages":"Article 121086"},"PeriodicalIF":4.5,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143911701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Percolation-based mean field theory for disordered particle packings 无序粒子堆积的基于渗流的平均场理论

IF 4.5 2区工程技术

Powder Technology Pub Date : 2025-04-30 DOI: 10.1016/j.powtec.2025.121088

Wenxiang Xu , Zhuangwei Ma , Junliang Fu , Yang Jiao

{"title":"Percolation-based mean field theory for disordered particle packings","authors":"Wenxiang Xu , Zhuangwei Ma , Junliang Fu , Yang Jiao","doi":"10.1016/j.powtec.2025.121088","DOIUrl":"10.1016/j.powtec.2025.121088","url":null,"abstract":"<div><div>Dense disordered packings of hard particles are useful models for granular materials, composites, colloids, foams, and condensed matter. It is very challenging to devise predictive theories of random packings, due to their intrinsic non-equilibrium and non-local nature. Here, we develop a mean-field theory for disordered particle packings by exploiting a recently discovered percolation transition of the hard-particle contact network that precedes the jamming transition. Assuming that the salient structural correlations in the final jammed packing are mainly inherited from those emerging in the percolating particle network, we devise a mean-field formalism that maps the hard particle percolation to analytically solvable Bethe-lattice models. This allows us to establish an analytical relation connecting the packing fraction <em>ϕ</em> and average contact number <em>Z</em> for a wide spectrum of congruent non-spherical hard particles in three-dimensional Euclidean space <strong>ℝ</strong><sup>3</sup>, where the particle shape factor is rescaled by the percolation critical exponent, reflecting the coupling of local and large scales in our mean-field formalism. The accuracy of our theory is ascertained by comparing its predictions of <em>ϕ</em> to the corresponding numerical values reported in literature. Our mean-field theory can be readily generalized to higher dimensions.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"460 ","pages":"Article 121088"},"PeriodicalIF":4.5,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144089339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0