International Journal of Adhesion and Adhesives最新文献_第2页

Strength improvement and failure analysis of dissimilar FDM printed single-lap joints with tailored interface geometry 采用定制界面几何形状的异种 FDM 印刷单搭接接头的强度改进和失效分析

IF 3.2 3区材料科学

International Journal of Adhesion and Adhesives Pub Date : 2024-11-01 DOI: 10.1016/j.ijadhadh.2024.103876

Ishan Manoj, Atul Jain

{"title":"Strength improvement and failure analysis of dissimilar FDM printed single-lap joints with tailored interface geometry","authors":"Ishan Manoj, Atul Jain","doi":"10.1016/j.ijadhadh.2024.103876","DOIUrl":"10.1016/j.ijadhadh.2024.103876","url":null,"abstract":"<div><div>Fused deposition modelling (FDM) offers design flexibility for thermoplastics tailored to specific structural optimization. Hybrid joints, combining adhesive bonding and mechanical interlocking, are effective in joining dissimilar thermoplastics. This study aims to strengthen dissimilar FDM-printed single-lap joints (SLJs) by understanding failure mechanisms and delaying damage initiation and propagation. Asymmetric stress due to differences in adherend stiffness concentrates higher stress on the lower stiffness adherend, justifying the need for geometric grading to improve joint strength and prevent premature failure. This study introduces a novel approach by incorporating positive and negative mechanical interlocking teeth on the bond-layer interface to enhance the performance of FDM-printed dissimilar SLJs using Polylactic acid (PLA) and Polyamide (PA). Dogbone samples of PA and PLA were FDM printed to characterize their tensile properties experimentally. A detailed parametric analysis investigates the influence of key geometrically graded tooth parameters on strength and failure behavior. Computational models, including cohesive zone modelling and ductile damage methods, are utilized to predict SLJ performance. Three distinct SLJs were manufactured with consistent printing parameters and orientations, each exhibiting a comparable overall geometric configuration. Uniaxial tensile tests were conducted to validate computational strength and failure modes experimentally. Results demonstrate a significant ≈59 % strength increase and ≈143 % improvement in failure strain for the optimized configuration compared to non-tailored SLJs.</div></div>","PeriodicalId":13732,"journal":{"name":"International Journal of Adhesion and Adhesives","volume":"136 ","pages":"Article 103876"},"PeriodicalIF":3.2,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572423","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}

引用次数: 0

Green transforming black liquors as a new HCHO scavenger in production eco urea formaldehyde-agro composites 在生产生态脲醛-农用复合材料过程中，将黑液作为新型 HCHO 清除剂进行绿色转化

IF 3.2 3区材料科学

International Journal of Adhesion and Adhesives Pub Date : 2024-10-30 DOI: 10.1016/j.ijadhadh.2024.103878

Altaf H. Basta, Vivian F. Lotfy

{"title":"Green transforming black liquors as a new HCHO scavenger in production eco urea formaldehyde-agro composites","authors":"Altaf H. Basta, Vivian F. Lotfy","doi":"10.1016/j.ijadhadh.2024.103878","DOIUrl":"10.1016/j.ijadhadh.2024.103878","url":null,"abstract":"<div><div>Innovative formaldehyde (HCHO)-scavenger based on black liquor is being developed to achieve eco-friendly low toxic urea formaldehyde (UF) adhesive. This scavenger will enhance the UF adhesive in production of agro-composites, complying with the environmental requirements. The HCHO-scavenger is synthesized from black liquor-based aerogels of various types of black liquors. The performance of the prepared scavengers is assessed via adsorption of HCHO; as well as its beneficial effect on properties of UF adhesive and UF-Palm fiber-composite. In order to produce a composite with mechanical properties and free-HCHO compliance with the standard specifications, the UF-scavenger system is optimized from its behavior. The data evidence the effective behavior of all investigated scavenger to improve bond strength of UF adhesive system (from 8.4 MPa to ∼ 18 MPa); and properties of UF-palm-composites, where the enhancement in modulus of rupture (MOR) and internal bond strength (IB), water repellent, reach to 50 %, 83 % and 7.7 %, respectively. In addition to success in producing eco-composites through reducing the free-HCHO of wood sample from 30.77 to 3.0–12.7 mg/100g with reduction percentages (58.7–90.3 %) exceeded those reported in the literature when carbon and silicon scavengers were used.</div></div>","PeriodicalId":13732,"journal":{"name":"International Journal of Adhesion and Adhesives","volume":"136 ","pages":"Article 103878"},"PeriodicalIF":3.2,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572407","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}

引用次数: 0

Influence of hygrothermal aging on the lifetime and mechanical properties of GFRP/Al adhesive joints 湿热老化对 GFRP/Al 粘合剂接头寿命和机械性能的影响

IF 3.2 3区材料科学

International Journal of Adhesion and Adhesives Pub Date : 2024-10-30 DOI: 10.1016/j.ijadhadh.2024.103880

Behnam Shahrezaee , Mohammad Latifi , Tohid Mirzababaie Mostofi

{"title":"Influence of hygrothermal aging on the lifetime and mechanical properties of GFRP/Al adhesive joints","authors":"Behnam Shahrezaee , Mohammad Latifi , Tohid Mirzababaie Mostofi","doi":"10.1016/j.ijadhadh.2024.103880","DOIUrl":"10.1016/j.ijadhadh.2024.103880","url":null,"abstract":"<div><div>The study aimed to investigate the impact of hygrothermal aging on the degradation of mechanical properties and predict the lifetime of adhesive joints between aluminum alloy (AA6061) and glass fiber-reinforced epoxy (GFRP) composites. The adhesive joints were prepared in a single lap joint (SLJ) configuration and subjected to hygrothermal conditions to induce aging. Immersion tests were conducted at a water temperature of 70 °C with varying aging periods (10, 18, 40, 54, 60, and 75 days) to assess the long-term performance and predict the lifetime of the joints. The tensile and shear strength of the adhesive joints were evaluated using a tensile test. The test was performed at room temperature (RT) with a speed rate of 1.3 mm/min. Among the different methods available for lifetime prediction, a semi-empirical approach was selected to analyze the changes in the mechanical properties of the adhesive joints. A comprehensive comparison was made between aged and unaged specimens. The experimental results revealed a reduction in the ultimate tensile and shear strength of the adhesive bonds over the 75-day aging period. The semi-empirical relationship used for long-term durability prediction of adhesive joint structures indicated a 78 % decrease in ultimate tensile strength for the adhesive joints over a one-year aging period. This highlights the significant influence of hygrothermal aging on the mechanical properties of the investigated adhesive joints. During the aged periods, various failure modes were observed, including adhesive failure, cohesive failure, and structural failure.</div></div>","PeriodicalId":13732,"journal":{"name":"International Journal of Adhesion and Adhesives","volume":"136 ","pages":"Article 103880"},"PeriodicalIF":3.2,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652771","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}

引用次数: 0

Creep damage laws for bonded joints under pure mode II loading 纯模式 II 加载下粘接接头的蠕变损伤规律

IF 3.2 3区材料科学

International Journal of Adhesion and Adhesives Pub Date : 2024-10-30 DOI: 10.1016/j.ijadhadh.2024.103879

R.F.M. Couto , M.F.S.F. de Moura , A.G. Magalhães , R.D.F. Moreira

{"title":"Creep damage laws for bonded joints under pure mode II loading","authors":"R.F.M. Couto , M.F.S.F. de Moura , A.G. Magalhães , R.D.F. Moreira","doi":"10.1016/j.ijadhadh.2024.103879","DOIUrl":"10.1016/j.ijadhadh.2024.103879","url":null,"abstract":"<div><div>Adhesively bonded joints have played an important role in several industries, mainly in automotive and aeronautics. A wide range of studies have been presented on the evaluation of the static behaviour of bonded joints, considering pure modes I and II, but also mixed-mode I + II loading. More recently, some developments have been done on the analysis of fatigue loading in this type of structural elements, introducing the importance of studying damage cohesively, along a determined period of time. As fatigue loading, creep loading can provide a significant contribution in terms of damage during the lifetime of a given bonded joint. Few studies were presented in the literature, regarding creep loading in bonded joints, so that a cohesive model capable of predicting the corresponding mechanical behaviour is needed. Twelve damage laws were postulated in this study, being used in a new cohesive zone model, predicting the creep behaviour of bonded joints under pure mode II loading. The corresponding implementation was proved, after an in-depth parametric analysis. The presented study constitutes a basis for future developments on the cohesive damage modelling of bonded joints, considering mixed-mode I + II loading scenarios.</div></div>","PeriodicalId":13732,"journal":{"name":"International Journal of Adhesion and Adhesives","volume":"136 ","pages":"Article 103879"},"PeriodicalIF":3.2,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572406","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}

引用次数: 0

Changes in the peel strength between the painting and first lining papers in Japanese scroll model samples 日本卷轴模型样品中绘画纸和第一层衬纸之间剥离强度的变化

IF 3.2 3区材料科学

International Journal of Adhesion and Adhesives Pub Date : 2024-10-30 DOI: 10.1016/j.ijadhadh.2024.103875

Kang Lee , Toshiharu Enomae , Masamitsu Inaba

{"title":"Changes in the peel strength between the painting and first lining papers in Japanese scroll model samples","authors":"Kang Lee , Toshiharu Enomae , Masamitsu Inaba","doi":"10.1016/j.ijadhadh.2024.103875","DOIUrl":"10.1016/j.ijadhadh.2024.103875","url":null,"abstract":"<div><div>To maintain the permanence of a painting in a hanging scroll until subsequent repairs are made, inhibiting not only the deterioration of the painting and lining papers but also inhibiting decrease in the adhesiveness between them is important because the first lining process significantly influences the mechanical support to the painting paper by attachment. Several studies have been conducted on the deterioration attributed to each component of the lining system. This study evaluated the adhesiveness behaviour by peel strength in the lined complex depending on the painting and lining materials with varied concentrations, as well as the fibre type of the lining paper. The lined complex consisting of the untreated painting paper showed the highest initial peel strength owing to the significant cohesiveness of the wheat starch paste layer, which was attributed to the paper's higher wettability and permeability, even though substrate failure occurred with longer ageing times. Degradative materials such as Cu<sup>2+</sup> attributed to pigments in the painting paper decomposed starch and decreased adhesiveness the fastest. Lined complexes coated with animal glue containing alum or Cu<sup>2+</sup> in the painting paper maintained the lowest peel strength during ageing owing to lower wettability and permeability, resulting in interfacial failure between the animal glue and the wheat starch paste layer. In addition, adhesiveness varied with different fibre types of the lining paper, depending on combined factors such as fibre length, surface roughness, shape, and intensity of hydroxyl groups. Thus, variable conditions attributed to fibre characteristics, materials used for lining, and degradative products in the painting paper influenced the changes in adhesion and adhesiveness. This variation contributed to different lining effects that influenced the life expectancy of the hanging scroll and determined the efficiency of the subsequent repair work.</div></div>","PeriodicalId":13732,"journal":{"name":"International Journal of Adhesion and Adhesives","volume":"136 ","pages":"Article 103875"},"PeriodicalIF":3.2,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652849","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}

引用次数: 0

Cavitation damage in rubber-like silicone adhesives 橡胶类硅酮粘合剂中的气蚀破坏

IF 3.2 3区材料科学

International Journal of Adhesion and Adhesives Pub Date : 2024-10-29 DOI: 10.1016/j.ijadhadh.2024.103867

Philipp Weißgraeber , Fabian Welschinger , Christoph Üffing

引用次数: 0

Mechanical analysis of bone fracture treatment with hydrogel adhesives 使用水凝胶粘合剂处理骨折的力学分析

IF 3.2 3区材料科学

International Journal of Adhesion and Adhesives Pub Date : 2024-10-29 DOI: 10.1016/j.ijadhadh.2024.103873

Yufei Wu , Jun Liu , Hao Liu , Zhen Zhang , Peijian Chen , Xuhao Huang

{"title":"Mechanical analysis of bone fracture treatment with hydrogel adhesives","authors":"Yufei Wu , Jun Liu , Hao Liu , Zhen Zhang , Peijian Chen , Xuhao Huang","doi":"10.1016/j.ijadhadh.2024.103873","DOIUrl":"10.1016/j.ijadhadh.2024.103873","url":null,"abstract":"<div><div>As a new kind of material with outstanding biocompatibility and tunable mechanical properties, hydrogel can serve in significant applications, such as biological tissue repair, biomedical implantation, and so on. However, the lack of the mechanical analysis of bone fracture treatment with hydrogel adhesives hinders the development of clinical applications. In this paper, a three dimensional bonded butt model is established to predict the mechanical behavior of treated bones by using a bilinear cohesive zone model. The force-displacement curve, ultimate load, and consumed energy, as well as damage evolution affected by various geometric and material factors are analyzed. It is found that designing hydrogel adhesives of suitable thickness and weight ratio is helpful for improving the strength of bonded structures. The strength of boned structures decreases due to Mullins effect of the hydrogel adhesive. The results should be helpful for predicting mechanical behavior of bonded bone with hydrogel adhesives, and inspiring more works on the applications in clinical practice.</div></div>","PeriodicalId":13732,"journal":{"name":"International Journal of Adhesion and Adhesives","volume":"136 ","pages":"Article 103873"},"PeriodicalIF":3.2,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572420","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}

引用次数: 0

The sessile drop work of adhesion revisited 无梗水滴附着功的再认识

IF 3.2 3区材料科学

International Journal of Adhesion and Adhesives Pub Date : 2024-10-28 DOI: 10.1016/j.ijadhadh.2024.103872

J.F. Ou , A. Amirfazli , S.F. Chini

{"title":"The sessile drop work of adhesion revisited","authors":"J.F. Ou , A. Amirfazli , S.F. Chini","doi":"10.1016/j.ijadhadh.2024.103872","DOIUrl":"10.1016/j.ijadhadh.2024.103872","url":null,"abstract":"<div><div>Work of adhesion per unit area of the interface to separate two distinct phases, and creating new interfaces. For the case of sessile drop, the Young-Dupre equation is usually used to express the work of adhesion, but it assumes the newly formed drop preserves its shape after detachment, which is not correct. Also, initial and final drop shapes cannot provide the work of adhesion. We argued that the work of adhesion depends on the path (despite the internal energy), and suggest a methodology to calculate the work of adhesion, based on calculating the mechanical work during the detachment, i.e. integration of drop centroid displacement times the external resistive forces. To put things into perspective, a 4 <span><math><mrow><mi>μ</mi><mi>l</mi></mrow></math></span> sessile water drop was studied with initial (advancing) and receding contact angles of 79.7° ± 0.9°, 60.2° ± 0.8°, respectively. The direct calculation of work of adhesion using the developed methodology in this paper gives 0.03 J/m<sup>2</sup>, while Young-Dupre gives 0.085 J/m<sup>2</sup>, and calculating the work of adhesion based on initial (sessile) and final (full sphere) states of the drop gives a negative value, i.e. −1.49 J/m<sup>2</sup>. So, neither Young-Dupre relation nor the initial and final energy states of drop can be used to calculate the work of adhesion, and detachment path should be considered in the calculation of work of adhesion.</div></div>","PeriodicalId":13732,"journal":{"name":"International Journal of Adhesion and Adhesives","volume":"136 ","pages":"Article 103872"},"PeriodicalIF":3.2,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554708","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}

引用次数: 0

Study on viscoelastic properties and rheological properties of SBS modified asphalt for road use with service life 道路用 SBS 改性沥青的粘弹性能和流变性能及使用寿命研究

IF 3.2 3区材料科学

International Journal of Adhesion and Adhesives Pub Date : 2024-10-26 DOI: 10.1016/j.ijadhadh.2024.103870

Shuang Chen , Chuanfeng Zheng , Wuxing Chen , Wei Guo , Zhiqiang Wei , Hanjun Li , Junpeng Xu

{"title":"Study on viscoelastic properties and rheological properties of SBS modified asphalt for road use with service life","authors":"Shuang Chen , Chuanfeng Zheng , Wuxing Chen , Wei Guo , Zhiqiang Wei , Hanjun Li , Junpeng Xu","doi":"10.1016/j.ijadhadh.2024.103870","DOIUrl":"10.1016/j.ijadhadh.2024.103870","url":null,"abstract":"<div><div>SBS modified asphalt is an important material in the construction of high-grade highway, and its performance changes directly affect the pavement performance. In this study, SBS modified asphalt was extracted from the actual pavement with different service years, and the rheological properties of SBS modified asphalt with different service years were studied by macroscopic test and microscopic molecular dynamics simulation. The macroscopic test results show that the needle penetration value of SBS modified asphalt increases by 50.6 % after two years of service, and the viscosity of SBS modified asphalt increases by 54.8 % after 12 years of service. With the increase of service life, G∗ and G″ of SBS modified asphalt showed an increasing trend, and δ and G’’/G’ showed a decreasing trend. The molecular dynamics simulation results of SBS modified asphalt were consistent with the macroscopic experimental results. The rheological properties of SBS modified asphalt showed a decreasing trend with the service life, and the interfacial energies between SBS modified asphalt and aggregate also showed a decreasing trend. The research in this paper will provide a theoretical basis for the future study of the deterioration law of SBS modified asphalt and the formulation of road maintenance plan.</div></div>","PeriodicalId":13732,"journal":{"name":"International Journal of Adhesion and Adhesives","volume":"136 ","pages":"Article 103870"},"PeriodicalIF":3.2,"publicationDate":"2024-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554707","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}

引用次数: 0

The influence of filler types and content on the curing behavior and properties of a bio-based polyurethane engineered sealant 填料类型和含量对生物基聚氨酯工程密封胶固化行为和性能的影响

IF 3.2 3区材料科学

International Journal of Adhesion and Adhesives Pub Date : 2024-10-22 DOI: 10.1016/j.ijadhadh.2024.103866

Zengping Zhang , Xiaosong Liu , Xiaoyi Ban , Jiajun Ji , Peijun Tian , Yang Yang

{"title":"The influence of filler types and content on the curing behavior and properties of a bio-based polyurethane engineered sealant","authors":"Zengping Zhang , Xiaosong Liu , Xiaoyi Ban , Jiajun Ji , Peijun Tian , Yang Yang","doi":"10.1016/j.ijadhadh.2024.103866","DOIUrl":"10.1016/j.ijadhadh.2024.103866","url":null,"abstract":"<div><div>Polyurethane (PU) sealants are widely used in practical projects to fill road cracks, extend road life and increase the strength of construction joints. And the fillers not only reinforce the sealant, but also effectively reduce costs. In this paper, a series of experiments were carried out to investigate the effects of filler types and contents on the curing behavior and properties of a novel bio-based PU sealant. Firstly, the optimum filler type was determined by fluorescence microscopy (FM) test and physical properties test. The dispersion of different fillers of different contents in the sealant and its effect on the mechanical properties were determined. Secondly, the effect of fillers on the curing behavior was investigated using Fourier transform infrared spectroscopy (FTIR), gel time experiment and surface drying time experiment. The cross-section surface micro-morphologies of the specimens after tensile tests were analyzed by scanning electron microscopy (SEM). Finally, the viscoelasticity and low-temperature properties were determined using dynamic mechanical analysis (DMA). The high-temperature properties of sealant were investigated using thermogravimetric (TG) analysis. The results showed that precipitated calcium carbonate (PCC) was the best filler. Moreover, fumed silica (FS), as a reactive filler, significantly influences the performance of the sealant. With the increase of filler content, the mechanical and high temperature properties of the sealant were enhanced. And the curing process was accelerated. But the low-temperature performance was reduced. Besides, excessive amount of PCC was worse to its uniform dispersion in the sealant and lead to defections in the materials, reducing the strength of the sealant. The optimum PCC content was recommended to be 10 wt%.</div></div>","PeriodicalId":13732,"journal":{"name":"International Journal of Adhesion and Adhesives","volume":"136 ","pages":"Article 103866"},"PeriodicalIF":3.2,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533830","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}

引用次数: 0