Theoretical and Applied Fracture Mechanics最新文献_第7页

Influence mechanism of void hole spacing on blast-induced crack propagation 孔洞间距对爆致裂纹扩展的影响机理

IF 5 2区工程技术

Theoretical and Applied Fracture Mechanics Pub Date : 2025-06-29 DOI: 10.1016/j.tafmec.2025.105067

Buqing Liu , Hong Su , Yue Gong , Ziru Guo , Ying Xu , Guodong Chen

{"title":"Influence mechanism of void hole spacing on blast-induced crack propagation","authors":"Buqing Liu , Hong Su , Yue Gong , Ziru Guo , Ying Xu , Guodong Chen","doi":"10.1016/j.tafmec.2025.105067","DOIUrl":"10.1016/j.tafmec.2025.105067","url":null,"abstract":"<div><div>Void holes structures are widely present in natural rock masses and frequently emerge equivalently in engineering due to delayed initiation designs in blasting, significantly influencing the propagation behavior of blast-induced cracks. To investigate the regulatory mechanism of void hole spacing on blast-induced crack propagation characteristics, this study employed dynamic laser caustics experiments combined with AUTODYN numerical simulations to systematically examine the dynamic fracture behavior of blast-induced cracks under varying void hole spacings. The results indicate that void holes exhibit remarkable inhibitory effects on crack propagation. As the void hole spacing decreases from 40 mm to 10 mm, the blast crack propagation length decreases by 7.2 %, 9.8 %, 12.9 % and 17.4 %, respectively. With the decrease of the void hole spacing, the inhibition intensity increases significantly. The crack propagation process demonstrates distinct phases: during the phase away from void holes, reflected waves temporarily promote crack extension; when cracks enter the inter-hole region, vertical compressive stress concentration zones markedly suppress crack growth; after cracks penetrate through void holes, diffraction waves cause a transient rebound in stress intensity factors. Numerical simulations show high consistency with experimental observations, validating the spatiotemporal regulatory effect of void hole spacing on blast-induced crack propagation mechanisms. These findings provide theoretical foundations and experimental support for damage control in surrounding rock, perimeter hole arrangement optimization, and precision contour blasting design in engineering practices.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"139 ","pages":"Article 105067"},"PeriodicalIF":5.0,"publicationDate":"2025-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144518542","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

Effects of the gently inclined bedding plane on the fracture behavior of a granular sandstone model containing single and double fissures 缓倾斜层理面对含单缝和双缝颗粒砂岩模型断裂行为的影响

IF 5 2区工程技术

Theoretical and Applied Fracture Mechanics Pub Date : 2025-06-29 DOI: 10.1016/j.tafmec.2025.105066

Chang’an Qin , Guowei Zhang , Bencan Pei , Xianglong Zhou , Meiben Gao

{"title":"Effects of the gently inclined bedding plane on the fracture behavior of a granular sandstone model containing single and double fissures","authors":"Chang’an Qin , Guowei Zhang , Bencan Pei , Xianglong Zhou , Meiben Gao","doi":"10.1016/j.tafmec.2025.105066","DOIUrl":"10.1016/j.tafmec.2025.105066","url":null,"abstract":"<div><div>Unusually, the stepped failure of massive rock masses can also be observed in layered rock masses. This failure is jointly influenced by fissures and gently inclined bedding planes. To investigate the effect of the gently inclined bedding plane on the propagation behavior of preexisting fissures, a granular sandstone model containing single and double fissures was created, and microcrack evolution, displacement fields, failure modes, and fracture mechanisms were analyzed. The tensile propagation transitions from a flaky to a linear form as the bedding inclination increases, encompassing cross-layer failure mode, cross-layer mixed failure mode, along-layer mixed failure mode, and along-layer failure mode. Importantly, a new stepped failure path has been identified. Through the analysis of displacement field evolution characteristics, it is determined that the fracture of the matrix rock is primarily governed by tensile stress emanating from the dilatancy area. Criteria for the extension of bedding fissures and cross-layer fissures have been established utilizing the energy release rate theory, elucidating the failure mechanisms of rock masses under the combined effects of multiple structural planes. This research offers theoretical support for understanding the catastrophic behavior of layered fractured rock masses.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"139 ","pages":"Article 105066"},"PeriodicalIF":5.0,"publicationDate":"2025-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144518539","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

Deep learning for upscaling complex nanoindentation images to predict fracture toughness 基于深度学习的复杂纳米压痕图像升级预测断裂韧性

IF 5 2区工程技术

Theoretical and Applied Fracture Mechanics Pub Date : 2025-06-27 DOI: 10.1016/j.tafmec.2025.105065

Erica Esatyana , A. Sakhaee-Pour

{"title":"Deep learning for upscaling complex nanoindentation images to predict fracture toughness","authors":"Erica Esatyana , A. Sakhaee-Pour","doi":"10.1016/j.tafmec.2025.105065","DOIUrl":"10.1016/j.tafmec.2025.105065","url":null,"abstract":"<div><div>Standard methods for characterizing fracture toughness, such as the Cracked Chevron Notched Brazilian Disc (CCNBD), require large samples that are typically not extracted from the subsurface to reduce costs. In practice, chips and cuttings are often available, but their properties do not necessarily reflect those of large samples because fracture toughness is size-dependent. This study demonstrates that deep learning can determine the fracture toughness of CCNBD specimens by interpreting the complex patterns of nanoindentation, which is applicable to small samples. First, the fracture toughness values of four CCNBD specimens were measured under pure mode I. Then, their semi-circular samples were indented and imaged 5,508 times, generating complex patterns. Outliers were removed after visually inspecting the images and analyzing their pixels. The remaining images were augmented threefold, increasing the dataset to 21,060. A deep learning model was then developed, with hyperparameters tuned through trial and error, to analyze the complex patterns. The model uses the convolutional base of VGG16, which was gradually unfrozen and combined with fully connected layers. The results show that deep learning can determine the normalized fracture toughness of CCNBD specimens with a mean squared error of 5.2 <em>×</em> 10<sup>−3</sup> on the test set. This finding is significant because upscaling from nanoindentation to CCNBD is not trivial due to heterogeneity. The proposed approach offers a promising method for characterizing fracture toughness in the subsurface using small samples.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"139 ","pages":"Article 105065"},"PeriodicalIF":5.0,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144611926","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

Influence of moisture desorption on dynamic mode I fracture behavior and crack propagation of coal: Experimental and theoretical Insights 水分解吸对煤的动态I型断裂行为和裂纹扩展的影响：实验和理论见解

IF 5 2区工程技术

Theoretical and Applied Fracture Mechanics Pub Date : 2025-06-25 DOI: 10.1016/j.tafmec.2025.105063

Junjun Feng , Wangyuan Liu , Ting Zhang , Qisong Huang , Houcheng Ding , Yankun Ma

{"title":"Influence of moisture desorption on dynamic mode I fracture behavior and crack propagation of coal: Experimental and theoretical Insights","authors":"Junjun Feng , Wangyuan Liu , Ting Zhang , Qisong Huang , Houcheng Ding , Yankun Ma","doi":"10.1016/j.tafmec.2025.105063","DOIUrl":"10.1016/j.tafmec.2025.105063","url":null,"abstract":"<div><div>Moisture desorption poses a significant challenge to coalbed methane (CBM) recovery in high-temperature coal reservoirs. This study investigated the effect of moisture desorption on mode I fracture of notched semi-circular bending (NSCB) coal samples using a split Hopkinson pressure bar (SHPB) system. A high-speed camera was used to record the dynamic crack propagation, and image processing methods were used to analyze the crack propagation characteristics. The results show that increasing the moisture desorption rate from 0% to 100% improves the dynamic fracture toughness by 37%. In addition, the crack propagation speed and crack tip opening displacement (CTOD) are increased by 28% and nearly 100%, respectively. The moisture desorption rate is positively correlated with the dynamic fracture toughness, crack propagation speed, and CTOD, which indicates that moisture desorption improves mode I fracture toughness and promotes crack propagation. Furthermore, the mechanisms by which moisture desorption affects coal microstructure were elucidated using an optical microscope, and a theoretical model was proposed to explain the effects of moisture desorption. The model suggests that the matrix contraction force induced by moisture desorption promotes crack propagation, while the surface tension and viscous resistance of the moisture inhibit it. As moisture desorbs, the effects of surface tension and viscous resistance decrease, thereby promoting crack propagation. The results provide theoretical guidance for enhancing CBM recovery in high-temperature coal reservoirs.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"139 ","pages":"Article 105063"},"PeriodicalIF":5.0,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144518543","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

Assessment of full-field J-integrals through digital image correlation using stress estimation based on measured strains 基于实测应变的应力估计，通过数字图像相关评估全场j积分

IF 5 2区工程技术

Theoretical and Applied Fracture Mechanics Pub Date : 2025-06-25 DOI: 10.1016/j.tafmec.2025.105064

Antti Forsström , Juha Kuutti , Bruno Reinaldo Goncalves , Sebastian Lindqvist

{"title":"Assessment of full-field J-integrals through digital image correlation using stress estimation based on measured strains","authors":"Antti Forsström , Juha Kuutti , Bruno Reinaldo Goncalves , Sebastian Lindqvist","doi":"10.1016/j.tafmec.2025.105064","DOIUrl":"10.1016/j.tafmec.2025.105064","url":null,"abstract":"<div><div>Application of digital image correlation (DIC) for full-field <em>J</em>-integral measurement with single-edge bending type SE(B) specimens, varying crack length-to-width ratios (<em>a<sub>0</sub></em>/W), and a ductile material was studied numerically and experimentally. The specimens were first modelled in FEM and the displacement data was treated as measurement data to validate the method. Experimental studies were then conducted to extract full-field <em>J</em>-integrals by DIC. The study shows comparable or slightly higher <em>J</em>-values obtained with the surface DIC measurement as with the ASTM E1820 standard. However, there are certain considerations regarding convergence of the full-field <em>J</em>-integrals when large scale yielding and large rotations are involved.</div><div>The small strain theory behind <em>J</em>-integral imposes a limitation on the full-field method once the rotations are large enough to impose an error in the measured gradients. The rotations cause an inherent negative error in the measured gradients, which in turn imposes a negative error in the measured <em>J</em>. This is especially evident when the contour or domain for <em>J</em>-integral is taken far-field and contains areas that exhibit close to zero strains. A simple remedy is to determine the <em>J</em>-integral relatively close to the crack tip avoiding large rotations, while still also avoiding the crack tip to avoid strain localizations.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"139 ","pages":"Article 105064"},"PeriodicalIF":5.0,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144501769","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

Fracture behavior and deterioration mechanisms of hydraulic concrete under wet-dry cycles with variable temperature 变温度干湿循环条件下水工混凝土断裂行为及劣化机理

IF 5 2区工程技术

Theoretical and Applied Fracture Mechanics Pub Date : 2025-06-24 DOI: 10.1016/j.tafmec.2025.105061

XuanYi Zhu , DongJian Zheng , Yanan Zhang , XuDong Chen , Linze Chen

{"title":"Fracture behavior and deterioration mechanisms of hydraulic concrete under wet-dry cycles with variable temperature","authors":"XuanYi Zhu , DongJian Zheng , Yanan Zhang , XuDong Chen , Linze Chen","doi":"10.1016/j.tafmec.2025.105061","DOIUrl":"10.1016/j.tafmec.2025.105061","url":null,"abstract":"<div><div>Photovoltaic pumped storage power plants, as a kind of green low-carbon, flexible and adjustable power source with potential for large-scale development, are often affected by environmental factors such as variable temperature and wet/dry cycling during operation, which leads to the degradation of the mechanical properties of the panels and thus affects the structural stability. In this study, wet and dry cyclic concrete specimens were prepared by simulating a 12-hour cycle of high temperature drop (80 °C → 20 °C) conditions in a homemade test chamber. The damage mechanism of the fracture resistance of deteriorated concrete and the crack extension process were investigated by using three-point bending test combined with acoustic emission multiparameter monitoring technique. The experimental results show that the fracture instability load of the deteriorated material decreases gradually and the double-k fracture parameters change significantly; the average crack initiation toughness decreases by 44.02 % and the average instability toughness decreases by 20.39 %. The proportion of shear components in the fracture process increased from 17.1 % to 26.6 % with the increase in the number of cycles. The crack extension path shows a shift from aggregate penetration to interface bypassing, and exhibits random extension of microcracks, spatial non-homogeneity, and local energy aggregation effect triggered by the synergistic effect of multiple factors. This study provides a theoretical basis for the stability of concrete structures in pumped storage power stations.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"139 ","pages":"Article 105061"},"PeriodicalIF":5.0,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144491798","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

Energy–Evolution behaviour of fractured granite under triaxial loading and unloading at high confining pressure 高围压下三轴加卸载破碎花岗岩能量演化行为

IF 5 2区工程技术

Theoretical and Applied Fracture Mechanics Pub Date : 2025-06-24 DOI: 10.1016/j.tafmec.2025.105062

Hao Hu , Xinping Li , Junhong Huang , Tengsheng Zhang , Zixu Wang , Yi Luo , Tingting Liu

{"title":"Energy–Evolution behaviour of fractured granite under triaxial loading and unloading at high confining pressure","authors":"Hao Hu , Xinping Li , Junhong Huang , Tengsheng Zhang , Zixu Wang , Yi Luo , Tingting Liu","doi":"10.1016/j.tafmec.2025.105062","DOIUrl":"10.1016/j.tafmec.2025.105062","url":null,"abstract":"<div><div>Abrupt changes in stress conditions during deep underground excavation can trigger sudden instability in rock masses, posing unpredictable threats to construction safety. To identify precursors of such failure, this study conducted triaxial tests on granite specimens containing prefabricated fractures. One group was continuously loaded to failure, while the other group was unloaded after reaching 75 % of peak strength. Acoustic emission (AE) signals were recorded throughout each test, while external work, elastic strain energy, and dissipated energy were calculated from stress–strain data. Shannon entropy was then introduced to analyze, from another perspective, the evolution of AE energy-level distributions during crack propagation. Results indicate that: (1) Under identical confining pressure, the unloading path induces significantly more sudden and violent failure than loading, with peak AE count rates and cumulative energy approximately one order of magnitude greater during unloading. (2) The entropy curve exhibits a sudden change earlier than the cumulative-energy curve, that means a smaller “warning strain” and can provide additional time for preventive measures. (3) The fracture dip angle has a significant impact on both specimen strength and failure precursors. A dip angle of 60°is the most unfavorable, showing the lowest strength under both loading and unloading paths, and the smallest warning strain under unloading path.This study demonstrates that integrating Shannon entropy with traditional AE-energy parameters provides earlier and more reliable precursor signals under extreme conditions, such as high confining-pressure unloading. The proposed entropy–energy joint criterion thus offers a robust physical foundation and practical method for predicting deep-rockburst hazards and assessing rock-mass stability.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"139 ","pages":"Article 105062"},"PeriodicalIF":5.0,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144501770","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

Prediction of fatigue crack propagation life of welded joints considering three-dimensional undercut characteristics 考虑三维凹边特性的焊接接头疲劳裂纹扩展寿命预测

IF 5 2区工程技术

Theoretical and Applied Fracture Mechanics Pub Date : 2025-06-23 DOI: 10.1016/j.tafmec.2025.105056

Sheng Chen , Suming Xie , Tao Li , Jian Wang

引用次数: 0

A simulation algorithm for crack propagation in rocks subjected to frost swelling pressure 霜胀压力作用下岩石裂纹扩展的模拟算法

IF 5 2区工程技术

Theoretical and Applied Fracture Mechanics Pub Date : 2025-06-23 DOI: 10.1016/j.tafmec.2025.105059

Manman Liu , Fangtong Wang

{"title":"A simulation algorithm for crack propagation in rocks subjected to frost swelling pressure","authors":"Manman Liu , Fangtong Wang","doi":"10.1016/j.tafmec.2025.105059","DOIUrl":"10.1016/j.tafmec.2025.105059","url":null,"abstract":"<div><div>The crack propagation inside rocks subjected to frost swelling pressure is one of the main factors threatening the safety of rock engineering. The existing frost crack simulation algorithms are difficult to model the real shapes of cracks, and most of them are limited to the sample scale. Therefore, a novel algorithm for simulating crack propagation in rocks under frost swelling pressure is proposed. The proposed algorithm can generate frost cracks with realistic morphology and is applicable to rocks at multiple scales. The stress concentration effect is involved to simulate frost cracks in a two-dimensional plane based on Griffith criterion. The Minkowski function is employed to quantify the impact of various factors on frost cracks, including the number of freeze–thaw cycles, initial crack, and the boundary condition of the computational domain. Moreover, the coordinate information of the generated cracks can be extracted to establish the fractured rock model in numerical simulation software. The algorithm has been extended to various scales to explore the impact of frost cracks on the deformation properties of rock samples and slope stability. The proposed algorithm can clarify the evolution process of frost cracks, providing references for evaluating the safety of rock engineering.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"139 ","pages":"Article 105059"},"PeriodicalIF":5.0,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144480818","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

Using sand 3D printing, digital image processing technology and DEM to investigate rock hole-fissure interaction mechanisms 利用砂石3D打印、数字图像处理技术和DEM研究岩石孔-裂隙相互作用机理

IF 5 2区工程技术

Theoretical and Applied Fracture Mechanics Pub Date : 2025-06-23 DOI: 10.1016/j.tafmec.2025.105058

Zhenyu Zhu , Mengyao Jiang , Shuyang Yu , Yifei Li

{"title":"Using sand 3D printing, digital image processing technology and DEM to investigate rock hole-fissure interaction mechanisms","authors":"Zhenyu Zhu , Mengyao Jiang , Shuyang Yu , Yifei Li","doi":"10.1016/j.tafmec.2025.105058","DOIUrl":"10.1016/j.tafmec.2025.105058","url":null,"abstract":"<div><div>Holes and fissures in rocks significantly influence rock engineering stability. This study employed sand 3D printing to create specimens with various hole-fissure combinations. Uniaxial compression tests were conducted, and DIC and DEM were used to analyze crack propagation. Results showed that seven crack types were identified. The single hole-fissure specimen had the highest peak strength, while in double hole-fissure specimens, peak strength increased with larger vertical hole distance <em>d</em> and fissure angle <em>α</em>. The number of cracks was inversely proportional to peak strength, decreasing as <em>d</em> increased and dropping sharply when <em>α</em> ranged from 30° to 60°. Crack initiation mechanisms under different circumstances were discussed. The research findings can provide valuable insights for accurately understanding the fracture mechanisms of rock masses containing hole-fissure combination structures and serve as a reference for predicting and preventing rock engineering disasters. Meanwhile, the research comprehensively adopted sand 3D printing, DIC technology and DEM to study the hole-fissure interaction mechanisms, providing a new method to efficiently study the mechanisms of rock failure.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"139 ","pages":"Article 105058"},"PeriodicalIF":5.0,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144491799","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