Aerotecnica Missili & Spazio最新文献_第2页

Accuracy Evaluation of Higher-Order Structural Theories for Stiffened Beams Using Neural Networks 用神经网络评价加劲梁高阶结构理论的精度

Aerotecnica Missili & Spazio Pub Date : 2026-07-01 DOI: 10.1007/s42496-026-00324-5

M. Petrolo, G. Candita, A. Pagani, E. Carrera

{"title":"Accuracy Evaluation of Higher-Order Structural Theories for Stiffened Beams Using Neural Networks","authors":"M. Petrolo, G. Candita, A. Pagani, E. Carrera","doi":"10.1007/s42496-026-00324-5","DOIUrl":"10.1007/s42496-026-00324-5","url":null,"abstract":"<div><p>This paper presents a machine learning-based surrogate framework for predicting the accuracy of higher-order beam theories in the analysis of isotropic structures with longitudinal stiffeners and transverse ribs. The proposed approach maps the physical and geometric parameters of the beams directly to the accuracy of a selected structural theory, enabling the selection of the minimum set of generalized displacement variables required to achieve the desired accuracy for a given set of input parameters. The training dataset is generated using the Carrera Unified Formulation and comprises combinations of generalized variables stemming from polynomial expansions up to the fourth order. Unlike previous studies, the input space explicitly includes physical cross-sectional parameters, as well as the presence and positions of stringers and ribs. The full dataset, encompassing all combinations of the considered structural theories and cases, comprises millions of analyses; however, accurate predictions are achieved using Deep Neural Networks with only approximately 1% of the full dataset for training. The results show that the proposed surrogate model reliably predicts the accuracy of a structural theory with good generalization capabilities. Concerning the most influential generalized variables, high accuracy in natural frequency prediction is generally achieved when approximately 60% of the fourth-order expansion terms are retained; all second-order terms are essential, while selected third- and fourth-order terms significantly influence the response.</p></div>","PeriodicalId":100054,"journal":{"name":"Aerotecnica Missili & Spazio","volume":"105 6","pages":"987 - 1010"},"PeriodicalIF":0.0,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s42496-026-00324-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149098084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Aerodynamic and Stability Analyses of Osculating Cone Waveriders with Variable Tip Shapes 变端部形状锥形波源的气动稳定性分析

Aerotecnica Missili & Spazio Pub Date : 2026-06-19 DOI: 10.1007/s42496-026-00321-8

Agnivo Ghosh, Anagha G. Rao, Srisha M. V. Rao

{"title":"Aerodynamic and Stability Analyses of Osculating Cone Waveriders with Variable Tip Shapes","authors":"Agnivo Ghosh, Anagha G. Rao, Srisha M. V. Rao","doi":"10.1007/s42496-026-00321-8","DOIUrl":"10.1007/s42496-026-00321-8","url":null,"abstract":"<div><p>Waveriders represent unique aerodynamic configurations with the ability to achieve excellent aerodynamic efficiency for high-speed cruising vehicles. The osculating cone waverider methodology provides significant flexibility in generating waverider shapes, but conventionally flat and anhedral waveriders have been studied, and there is a limited number of studies on dihedral waveriders. Further, a new design limit criterion is used to evaluate the non-dimensional tip height, which is higher than conventional designs. Three distinct osculating cone waveriders are generated with non-dimensional tip heights, characterized by anhedral (0.3), dihedral (1.7), and flat (1) configurations. Examination of the geometric characteristics indicates that the dihedral configuration demonstrates the highest volumetric efficiency, surpassing its anhedral counterpart by 15<span>(%)</span>. Simulations are performed under both on-design and off-design conditions. Specifically, under on-design conditions, the anhedral waverider exhibits superior aerodynamic performance compared to the other two configurations, boasting an L/D ratio that is 18<span>(%)</span> higher than its dihedral counterpart. In off-design situations, both the dihedral and flat waveriders demonstrated stability in lateral and directional directions. The dihedral waverider exhibited higher rolling moment and yawing moment derivatives, indicating its superior lateral and directional stability compared to the flat waverider. However, the anhedral waverider, although directionally stable, showed lateral instability characterized by positive yawing and rolling moment derivatives. Additionally, all three waveriders were observed to be longitudinally unstable, displaying comparable pitching moment derivatives. The study also shows that a local surface inclination-based theory is able to explain aspects of the pressure distribution which affect the forces and moments over the body.</p></div>","PeriodicalId":100054,"journal":{"name":"Aerotecnica Missili & Spazio","volume":"105 6","pages":"937 - 957"},"PeriodicalIF":0.0,"publicationDate":"2026-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149098864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Preliminary PHM System Development for Harmonic Drives in Electromechanical Flight Control Systems 机电飞控系统谐波驱动PHM系统初步开发

Aerotecnica Missili & Spazio Pub Date : 2026-06-19 DOI: 10.1007/s42496-026-00323-6

Roberto Guida, Antonio C. Bertolino, Andrea De Martin, Massimo Sorli

{"title":"Preliminary PHM System Development for Harmonic Drives in Electromechanical Flight Control Systems","authors":"Roberto Guida, Antonio C. Bertolino, Andrea De Martin, Massimo Sorli","doi":"10.1007/s42496-026-00323-6","DOIUrl":"10.1007/s42496-026-00323-6","url":null,"abstract":"<div><p>Harmonic drives are commonly used in systems that demand high positional accuracy within a compact form factor. Despite these advantages, their use in aerospace applications is still relatively limited, primarily due to uncertainties associated with durability and long-term operational reliability. This work presents a preliminary dedicated prognostics and health management (PHM) framework aimed at fault detection and remaining useful life (RUL) oriented indicators estimation for harmonic drives employed in aerospace electromechanical actuators (EMAs), with particular focus on urban air mobility platforms. The proposed framework integrates model-based approaches with data-driven techniques to enhance fault identification, diagnostics, and prognostic capabilities. The research methodology comprises a comprehensive failure modes, effects, and criticality analysis (FMECA), along with the development of high-fidelity models capable of capturing both nominal and degraded system behavior. A wear-induced degradation scenario is selected as a representative case study. To support the analysis, an extensive simulation campaign is carried out to generate a representative dataset, from which meaningful health indicators suitable for both on-ground and in-flight condition monitoring are derived.</p></div>","PeriodicalId":100054,"journal":{"name":"Aerotecnica Missili & Spazio","volume":"105 6","pages":"971 - 986"},"PeriodicalIF":0.0,"publicationDate":"2026-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s42496-026-00323-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149098862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Simulating the Potential of an In-Space Fragmentation of the Lunar Reconnaissance Orbiter 模拟月球侦察轨道器在空间破碎的可能性

Aerotecnica Missili & Spazio Pub Date : 2026-06-19 DOI: 10.1007/s42496-026-00322-7

Nicolò Trabacchin, Cinzia Giacomuzzo, Lorenzo Olivieri

{"title":"Simulating the Potential of an In-Space Fragmentation of the Lunar Reconnaissance Orbiter","authors":"Nicolò Trabacchin, Cinzia Giacomuzzo, Lorenzo Olivieri","doi":"10.1007/s42496-026-00322-7","DOIUrl":"10.1007/s42496-026-00322-7","url":null,"abstract":"<div><p>The rapid expansion of activities in the cislunar region introduces new challenges for ensuring the long-term safety and sustainability of lunar operations. With hundreds of missions planned in the coming decades, the risk of orbital congestion in Low Lunar Orbit (LLO) is becoming increasingly relevant. Recent conjunctions involving active spacecraft, such as NASA’s Lunar Reconnaissance Orbiter (LRO) and KARI’s Korea Pathfinder Lunar Orbiter (KPLO), underline the need for effective Space Situational Awareness (SSA) and Space Traffic Management (STM) strategies in this domain. This work presents a preliminary effort to characterize the potential debris environment in LLO through high-fidelity fragmentation simulations using the Collision Simulation Tool Solver (CSTS), a semi-empirical code developed at the University of Padova. Specifically, this study investigates two critical breakup scenarios: an explosion of the LRO and a collision between the LRO and the KPLO. The tool enables the modeling of complex breakup scenarios and the derivation of statistically representative debris populations for subsequent dynamical analyses. The resulting synthetic datasets provide an initial foundation for understanding the spatial distribution and evolution of debris clouds in the lunar environment. Such analyses are critical for supporting future mission design, risk assessment, and operational decision-making, ultimately contributing to the establishment of a sustainable framework for cislunar space operations.</p></div>","PeriodicalId":100054,"journal":{"name":"Aerotecnica Missili & Spazio","volume":"105 6","pages":"959 - 970"},"PeriodicalIF":0.0,"publicationDate":"2026-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s42496-026-00322-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149098863","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Evaluation of Generative Data Augmentation Approaches in Enhancing Aircraft Damage Detection Models 生成数据增强方法在飞机损伤检测模型中的应用

Aerotecnica Missili & Spazio Pub Date : 2026-06-11 DOI: 10.1007/s42496-026-00318-3

Salvatore Merola, Aditi Mhatre, Ann-Kathrin Koschlik, Michele Guida, Francesco Marulo

{"title":"Evaluation of Generative Data Augmentation Approaches in Enhancing Aircraft Damage Detection Models","authors":"Salvatore Merola, Aditi Mhatre, Ann-Kathrin Koschlik, Michele Guida, Francesco Marulo","doi":"10.1007/s42496-026-00318-3","DOIUrl":"10.1007/s42496-026-00318-3","url":null,"abstract":"<div><p>The scarcity of annotated datasets poses a major challenge to the robustness and predictive accuracy of deep learning models in detecting aircraft surface defects. This study investigates generative data augmentation as a solution to limited annotated data in aircraft surface damage detection. Carried out as part of the CINNABAR 2 project in collaboration with the DLR MRO Institute in Hamburg, Germany, the study compares Generative Adversarial Networks (GANs) and Diffusion Models in their ability to generate realistic synthetic images. The real dataset was collected using multiple acquisition systems, including smartphones and Digital Single Lens Reflex (DSLR) cameras. Synthetic image quality was evaluated through the Learned Perceptual Image Patch Similarity (LPIPS) metric, and other metrics commonly used in object detection tasks. The findings show that Diffusion Models surpass GANs, achieving lower LPIPS scores and improving detection performance by 12%, indicating greater realism, diversity, and effectiveness for training deep learning models.</p></div>","PeriodicalId":100054,"journal":{"name":"Aerotecnica Missili & Spazio","volume":"105 6","pages":"883 - 895"},"PeriodicalIF":0.0,"publicationDate":"2026-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s42496-026-00318-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149098642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Comparative Analysis of PSD Estimation Techniques for Wind Gust Signals: From Flight Campaigns to Satellite Data 阵风信号PSD估计技术的比较分析：从飞行活动到卫星数据

Aerotecnica Missili & Spazio Pub Date : 2026-05-29 DOI: 10.1007/s42496-026-00319-2

M. Valente, G. Palaia, E. Carrera

{"title":"Comparative Analysis of PSD Estimation Techniques for Wind Gust Signals: From Flight Campaigns to Satellite Data","authors":"M. Valente, G. Palaia, E. Carrera","doi":"10.1007/s42496-026-00319-2","DOIUrl":"10.1007/s42496-026-00319-2","url":null,"abstract":"<div><p>This paper presents a methodological analysis of wind gust spectra, with a focus on estimating the wind gust power spectral density (PSD). Three spectral estimation approaches are systematically investigated: zero-padding, Welch’s method, and a length-weighted PSD formulation. The main objective is to evaluate the accuracy, robustness, and practical suitability of these techniques when applied to wind-gust signals obtained from two distinct sources: measurements from onboard sensors collected during a dedicated flight test campaign and measurements from a low-Earth orbit (LEO) satellite platform. Comparative results show that Welch’s method yields the most stable and reliable PSD estimates for flight-test data, particularly in terms of variance reduction and spectral smoothness. The same approach can be extended to satellite-based signals; however, the inherently low sampling frequency of LEO data severely constrains their usable bandwidth. As a consequence, satellite-derived gust spectra are of limited relevance for detailed assessments of aircraft structural response and fatigue, although they may remain valuable for large-scale atmospheric characterization.</p></div>","PeriodicalId":100054,"journal":{"name":"Aerotecnica Missili & Spazio","volume":"105 6","pages":"897 - 921"},"PeriodicalIF":0.0,"publicationDate":"2026-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s42496-026-00319-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149098812","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Numerical Simulation Study on a Novel Spanwise Oscillating Wall Drag Reduction Method 一种新型跨向振荡壁面减阻方法的数值模拟研究

Aerotecnica Missili & Spazio Pub Date : 2026-05-20 DOI: 10.1007/s42496-026-00317-4

Zhao Peng Zhang, Zheng Yin Ye, Tiejun Zhang, Kun Ye

{"title":"Numerical Simulation Study on a Novel Spanwise Oscillating Wall Drag Reduction Method","authors":"Zhao Peng Zhang, Zheng Yin Ye, Tiejun Zhang, Kun Ye","doi":"10.1007/s42496-026-00317-4","DOIUrl":"10.1007/s42496-026-00317-4","url":null,"abstract":"<div><p>Spanwise wall oscillation is widely recognized as an effective active technique for turbulent drag reduction. In this study, a segmented spanwise wall oscillation (SSW) strategy is proposed, in which the wall is divided into several streamwise segments and adjacent segments oscillate in opposite spanwise directions. This configuration not only enhances the drag reduction performance of conventional spanwise oscillation but also enables self-balancing of driving forces through the counter-directional motion of neighboring segments. Direct numerical simulations (DNS) of turbulent channel flow at <i>Re</i><sub>τ</sub> = 200 are performed to systematically investigate the drag reduction characteristics of the segmented configuration. The wall is divided into four, eight, and sixteen streamwise segments, and simulations are conducted at an oscillation amplitude of A + = 12 over a range of oscillation periods <i>T</i><sup>+</sup> = 50–200. The results show that the segmented oscillation configuration can achieve higher drag reduction rates than the conventional oscillating wall. The optimal drag reduction increases with the number of segments, indicating that the segmentation pattern significantly influences the control performance. Flow structure analysis suggests that the reverse oscillation of adjacent segments generates localized disturbances at the interfaces, which modifies the spatial distribution of streamwise vortices and induces a characteristic bending of near-wall streaks. These structural modifications are associated with a redistribution of vorticity and a reduction in turbulent kinetic energy production, while the increase in dissipation remains relatively limited. Overall, the segmented oscillation strategy provides an effective approach for modulating near-wall turbulence structures and improving drag reduction performance, while offering potential advantages for practical implementation due to its force self-balancing characteristics.</p></div>","PeriodicalId":100054,"journal":{"name":"Aerotecnica Missili & Spazio","volume":"105 6","pages":"863 - 881"},"PeriodicalIF":0.0,"publicationDate":"2026-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149099047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A Parametric Life Cycle Approach for Circular and Sustainable Aircraft Design 循环和可持续飞机设计的参数化生命周期方法

Aerotecnica Missili & Spazio Pub Date : 2026-05-05 DOI: 10.1007/s42496-026-00316-5

Chiara Gastaldi, Eugenio Brusa, Antonello Spagnulo

引用次数: 0

Optimizing Unmanned Aerial Vehicle Path finding in Complex Urban Airspaces: A Hybrid Genetic Algorithm with Bidirectional and Greedy Initialization 复杂城市空域无人机寻径优化：一种双向贪婪初始化混合遗传算法

Aerotecnica Missili & Spazio Pub Date : 2026-04-09 DOI: 10.1007/s42496-026-00314-7

Harish Kumar Balakrishnan, Abhilash Suryan, Anu P. Alex, V. R. Jisha, Sonia S. Raj, Guang Zhang

{"title":"Optimizing Unmanned Aerial Vehicle Path finding in Complex Urban Airspaces: A Hybrid Genetic Algorithm with Bidirectional and Greedy Initialization","authors":"Harish Kumar Balakrishnan, Abhilash Suryan, Anu P. Alex, V. R. Jisha, Sonia S. Raj, Guang Zhang","doi":"10.1007/s42496-026-00314-7","DOIUrl":"10.1007/s42496-026-00314-7","url":null,"abstract":"<div>\u0000 \u0000 <p>Energy-efficient solutions are crucial for sustainable urban logistics, especially with the increasing reliance on Unmanned Aerial Vehicles (UAVs) in congested urban environments. Effective path planning in such scenarios must address challenges like high traffic density, obstructions, and energy constraints while ensuring safety and efficiency. This study focuses on aerial path planning for autonomous air mobility in obstacle dense low altitude urban air space, integrating energy-efficient strategies with optimal path planning techniques. Genetic Algorithms (GAs) are powerful optimization techniques known for their ability to efficiently explore large and complex solution spaces. Their iterative approach mimics natural selection, making them highly effective in identifying near-optimal solutions for complex, non-linear problems. A modified GA is proposed, incorporating greedy initialization based on Euclidean heuristics to optimize the initial population. Additionally, the initialization process includes a bidirectional approach, assigning half of the population from the goal to the start. These enhancements aim to improve convergence speed, solution quality, and computational efficiency. The performance of the modified GA is evaluated against a standard GA using a random maze generation algorithm designed to simulate urban airspaces with a high obstacle density. Comparative results demonstrate the superiority of the modified GA in navigating complex environments with reduced computational expense and faster convergence. This approach highlights the potential of integrating innovative initialization strategies within GAs to address the challenges of path planning in urban UAV logistics, paving the way for more sustainable and efficient aerial mobility solutions.</p>\u0000 </div>","PeriodicalId":100054,"journal":{"name":"Aerotecnica Missili & Spazio","volume":"105 5","pages":"833 - 851"},"PeriodicalIF":0.0,"publicationDate":"2026-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148459160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A Paradigm Shift to Assembly-like Finite Element Model Updating 向类装配式有限元模型更新的范式转变

Aerotecnica Missili & Spazio Pub Date : 2026-04-09 DOI: 10.1007/s42496-026-00313-8

Gabriele Dessena, Alessandro Pontillo, Dmitry I. Ignatyev, James F. Whidborne, Luca Zanotti Fragonara

{"title":"A Paradigm Shift to Assembly-like Finite Element Model Updating","authors":"Gabriele Dessena, Alessandro Pontillo, Dmitry I. Ignatyev, James F. Whidborne, Luca Zanotti Fragonara","doi":"10.1007/s42496-026-00313-8","DOIUrl":"10.1007/s42496-026-00313-8","url":null,"abstract":"<div>\u0000 \u0000 <p>In general, there is a mismatch between a finite element model (FEM) of a structure and its real behaviour. In aeronautics, this mismatch must be small because FEMs are a fundamental part of the development of an aircraft and of increasing importance with the trend to more flexible wings in modern designs. Iterative finite element model updating can be computationally expensive for complex structures, and surrogate models can be employed to reduce the computational burden. A novel approach for FEM updating, namely assembly-like, is proposed and validated using real experimental data from a flexible wing. The assembly-like model updating framework implies that the model is updated as parts are assembled. Benchmarking against the classical global, or one-shot, approach demonstrates that the proposed method is more computationally efficient, since a normalised workload proxy based on solver-reported model size and memory footprint indicates about 28% lower overall effort. Aapproximately 95% of the required solves are performed on lower-fidelity subassembly models with smaller equation counts and memory requirements. Despite the reduced reliance on full-wing evaluations, the new approach retains the fidelity, within 1% of a joint natural frequencies and modal shapes index, of the global approach.</p>\u0000 </div>","PeriodicalId":100054,"journal":{"name":"Aerotecnica Missili & Spazio","volume":"105 5","pages":"815 - 832"},"PeriodicalIF":0.0,"publicationDate":"2026-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s42496-026-00313-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148459155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0