Fire Technology最新文献_第9页

Post-fire Response of Partially Restrained Connections: Methodology and Application on Top & Seat Angles 部分约束连接的火灾后响应：顶角和座角的方法和应用

IF 2.4 3区工程技术

Fire Technology Pub Date : 2024-11-01 DOI: 10.1007/s10694-024-01660-3

Abdul Kader M. El Hamoui, Ahmad H. El Ghor, Elie G. Hantouche

{"title":"Post-fire Response of Partially Restrained Connections: Methodology and Application on Top & Seat Angles","authors":"Abdul Kader M. El Hamoui, Ahmad H. El Ghor, Elie G. Hantouche","doi":"10.1007/s10694-024-01660-3","DOIUrl":"10.1007/s10694-024-01660-3","url":null,"abstract":"<div><p>The post-fire response of partially restrained steel connections is characterized by the reduction in strength after exposure to a full heating–cooling cycle of a fire event. This reduction in strength constitutes one of the crucial factors in assessing the structural performance of partially restrained steel connections post-fire exposure. This paper proposes a methodology for investigating the post-fire response of bolted top and seat angle connections, which are widely used in steel buildings. To achieve this, finite element (FE) models are developed in ABAQUS. The methodology consists of, first, the development of FE beam-to-column connection designed to survive a fire event. The outcome is to compute the post-fire thermal axial forces while varying different geometric and load parameters that impact the behavior. Second, the computed post-fire thermal axial force, along with the post-fire mechanical properties, are both used in developing FE component connection models, which are then subjected to loading until failure. The results show that after a fire event, the load-bearing capacity of the top and seat angle connection decreases with higher fire temperatures. The decrease in connection capacity ranges from 30 to 87% of its initial strength after exposure to post-fire temperatures ranging from 200°C to 500°C, respectively. This methodology, conducted through 3D non-linear FE analysis, represents a significant step in assessing the remaining capacity of steel connections post-fire and offers preliminary data to support the development of design guidelines, offering engineers guidance on assessing the need for replacement or repair of structural members after a fire event. Further experimental work is recommended to investigate different connection configurations, in order to gain a better understanding of the percentage reduction in capacity for this type of connection.</p></div>","PeriodicalId":558,"journal":{"name":"Fire Technology","volume":"61 4","pages":"1729 - 1758"},"PeriodicalIF":2.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145160598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

An Experiment on a Real Building with Truss Roof to Validate Real-Time Early-Warning System for Fire-Induced Collapse 桁架屋盖火灾倒塌实时预警系统的试验研究

IF 2.4 3区工程技术

Fire Technology Pub Date : 2024-10-30 DOI: 10.1007/s10694-024-01671-0

Guo-Qiang Li, Jinyu Li, Shaojun Zhu, Chao Zhang, Bin Chen, Wei Ji, Yao Wang, Nan Chen, Honghui Qi, Xiaolin Yang, Liming Jiang, Yongfeng Nie, Qi Luo

{"title":"An Experiment on a Real Building with Truss Roof to Validate Real-Time Early-Warning System for Fire-Induced Collapse","authors":"Guo-Qiang Li, Jinyu Li, Shaojun Zhu, Chao Zhang, Bin Chen, Wei Ji, Yao Wang, Nan Chen, Honghui Qi, Xiaolin Yang, Liming Jiang, Yongfeng Nie, Qi Luo","doi":"10.1007/s10694-024-01671-0","DOIUrl":"10.1007/s10694-024-01671-0","url":null,"abstract":"<div><p>To reduce secondary casualties and support firefighters in making scientific decisions in rescue, a real-time early-warning system for fire-induced building collapse, with “real-time measurement, online data analysis, and real-time early warning” being its core, has been developed. To validate the effectiveness of the system, a fire-induced collapse test on a real building with a truss roof was conducted. The basic framework of the early-warning system is firstly reviewed. The test program is then introduced, including basic information about the test structure, loading scheme, measuring points, and equipment. The detailed test phenomena, and the thermal and structural responses are further described and analyzed. The test results revealed that the temperature distribution within the tested building is highly non-uniform, and the maximum temperature of the gas and steel components reached 900°C. The collapse mode of the truss was successfully identified by the early-warning algorithm based on the evolution laws of the displacements at the key joints of the truss, including prominent vertical joint displacements, buckling of the steel member of the truss, and bending failure of the top reinforced concrete chord of the truss. The test building collapsed after 4253 s after the ignition of the fire, and the developed early-warning system issued the remaining time to collapse in real time before the collapse of the test building. It is demonstrated that the predicted remaining time to collapse by the early-warning system was close to the real value.</p></div>","PeriodicalId":558,"journal":{"name":"Fire Technology","volume":"61 4","pages":"2013 - 2046"},"PeriodicalIF":2.4,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145170772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

Thermomechanical Analysis of Reinforced Concrete Beams Under Fire Situation: A Comparison Between Conventional Concrete and UHPC 火灾条件下钢筋混凝土梁的热力学分析：常规混凝土与超高性能混凝土的比较

IF 2.4 3区工程技术

Fire Technology Pub Date : 2024-10-29 DOI: 10.1007/s10694-024-01657-y

F. S. Duarte, R. Carrazedo, J. Munaiar Neto

{"title":"Thermomechanical Analysis of Reinforced Concrete Beams Under Fire Situation: A Comparison Between Conventional Concrete and UHPC","authors":"F. S. Duarte, R. Carrazedo, J. Munaiar Neto","doi":"10.1007/s10694-024-01657-y","DOIUrl":"10.1007/s10694-024-01657-y","url":null,"abstract":"<div><p>Ultra-High-Performance Concrete (UHPC) is known for its remarkable durability and strength, owing to its dense microstructure. However, its reduced porosity poses challenges when exposed to high temperatures, making it vulnerable to fire damage compared to conventional concrete. This paper presents thermomechanical numerical simulations of reinforced concrete beams, focusing on understanding the behavior of UHPC and conventional concrete under elevated temperatures. We employed the software ABAQUS and validated thermomechanical properties obtained by experimental tests without occurrence of spalling available on literature. Beams with equivalent strength were modeled, subjected to mechanical loads, and heated following the ISO 834 fire curve. A parametric study was conducted to investigate the influence of the applied load level, concrete cover and compression strength on the behavior of the UHPC. Results showed that UHPC beams heated up significantly faster, reaching temperatures <span>(hbox {182},^{circ })</span>C higher than conventional concrete beams after 180 min. This faster heating leads to greater displacements and reduced fire resistance, with UHPC beams achieving about 30 min less of resistance. However, further experimental research is recommended to confirm these results and refine the properties of UHPC. From the parametric analyses, we observed that improving the concrete’s strength led to a resistance increase of only up to 5%. Improved results were achieved with the addition of concrete cover. With load increases of 15% and 25%, the resistance decreased by 17.2% and 27.1%, respectively. These results emphasize the importance of considering concrete type in fire safety design, allowing for the definition of appropriate parameters for fire safety standards.</p></div>","PeriodicalId":558,"journal":{"name":"Fire Technology","volume":"61 4","pages":"1647 - 1668"},"PeriodicalIF":2.4,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145171704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

Fire Resistance of Steel Rack Frames: Assessment, Reinforcement and Collapse Mitigation Strategies 钢架框架的耐火性能：评估、加固和减少倒塌策略

IF 2.4 3区工程技术

Fire Technology Pub Date : 2024-10-29 DOI: 10.1007/s10694-024-01664-z

Marco Simoncelli, Marco Zucca, Flavio Stochino

{"title":"Fire Resistance of Steel Rack Frames: Assessment, Reinforcement and Collapse Mitigation Strategies","authors":"Marco Simoncelli, Marco Zucca, Flavio Stochino","doi":"10.1007/s10694-024-01664-z","DOIUrl":"10.1007/s10694-024-01664-z","url":null,"abstract":"<div><p>Steel rack frames are used to suitably store goods and products and are constructed by means the use of thin-walled cold-formed components. Their competitiveness on the market essentially depends on the total weight of the framed system. In fact, these structures allow for the storage of material that is hundreds or even thousands of times more expensive than the rack itself. Despite great efforts made on seismic and static design, limited attention has been given to the problem of fire design and to the robustness of such structures. No specific design rules or design procedures have been developed until now. Nowadays, the only way to protect these frames against fire is the use of active systems like sprinklers or controlled oxygen chambers. Unfortunately, these solutions cannot be always adopted and a suitable strategy that avoids the global structural collapse following a fire is still necessary. In this paper a parametric analysis is proposed to deeply understand the behavior of steel storage pallet racks against fire. In particular, starting from an existing rack configuration with nine bays and five storage levels, different fire scenarios were modeled by changing the fire position along the frame. Moreover, the progressive collapse of the rack is discussed, and a reinforcing strategy is proposed. Finally, an example of the application of a sprinkler system is discussed, showing the advantages and weaknesses of this solution.</p></div>","PeriodicalId":558,"journal":{"name":"Fire Technology","volume":"61 4","pages":"1861 - 1883"},"PeriodicalIF":2.4,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145171703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

Numerical Modeling of Circular Concrete-Filled Double Steel Tubular Columns Under Fire Incorporating a New Concrete Confinement Model 基于新型混凝土约束模型的圆形双钢管混凝土柱火灾数值模拟

IF 2.4 3区工程技术

Fire Technology Pub Date : 2024-10-29 DOI: 10.1007/s10694-024-01674-x

Hongjie Zhu, Shicai Chen, Mizan Ahmed, Qing Quan Liang

{"title":"Numerical Modeling of Circular Concrete-Filled Double Steel Tubular Columns Under Fire Incorporating a New Concrete Confinement Model","authors":"Hongjie Zhu, Shicai Chen, Mizan Ahmed, Qing Quan Liang","doi":"10.1007/s10694-024-01674-x","DOIUrl":"10.1007/s10694-024-01674-x","url":null,"abstract":"<div><p>The internal circular steel tube provides considerable confinement to the core concrete in a Circular Concrete-Filled Double Steel Tubular (CCFDST) column exposed to fire. However, no constitutive model has been developed for the core concrete at elevated temperatures considering confinement. This paper develops a numerical modeling method for fire resistance of CCFDST columns exposed to fire, which incorporates a confinement-dependent model for concrete at elevated temperatures. The confinement-dependent model is implemented through a MATLAB algorithm. The algorithm incorporates several segments: an average temperature model is proposed to address the temperature-gradient problem within a CCFDST column; the temperature-dependent failure criterion is formulated for determining the compressive strength of confined concrete; the temperature-dependent axial-to-lateral strain relation is established; equations are derived for calculating the instantaneous confining stress on the core concrete exerted by the inner steel tube; and an automatic error-control algorithm is designed to enforce the accuracy of the proposed stress–strain model for the core concrete. To verify the proposed model, the finite element model developed using ABAQUS is presented, which incorporates the proposed constitutive model for the core concrete. The comparative analysis shows that the developed finite element model predicts well with the existing test results. This suggests that the proposed model is reliable and can be implemented in numerical models for the fire performance simulations of CCFDST columns.</p></div>","PeriodicalId":558,"journal":{"name":"Fire Technology","volume":"61 4","pages":"2105 - 2137"},"PeriodicalIF":2.4,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145171702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

How to Properly Account for Slope Effect in Byram’s Convective Number: A New Proposal 如何合理考虑拜拉姆对流数中的斜率效应：一个新建议

IF 2.4 3区工程技术

Fire Technology Pub Date : 2024-10-27 DOI: 10.1007/s10694-024-01670-1

D. Morvan, G. Accary

引用次数: 0

Impact of PVC Pyrolysis on Gasoline Identification in Fire Debris Analysis 聚氯乙烯热解对火灾碎屑分析中汽油识别的影响

IF 2.4 3区工程技术

Fire Technology Pub Date : 2024-10-26 DOI: 10.1007/s10694-024-01659-w

Zhengzhe Zang, Yingzhe Li, Lujia Liang, Peiwen Qian, Xiaoxiao Sun, Jing Jin, Qianqian Zhang, Zhenwen Sun

{"title":"Impact of PVC Pyrolysis on Gasoline Identification in Fire Debris Analysis","authors":"Zhengzhe Zang, Yingzhe Li, Lujia Liang, Peiwen Qian, Xiaoxiao Sun, Jing Jin, Qianqian Zhang, Zhenwen Sun","doi":"10.1007/s10694-024-01659-w","DOIUrl":"10.1007/s10694-024-01659-w","url":null,"abstract":"<div><p>To obtain a more comprehensive understanding of the matrix interference mechanism, polyvinyl chloride (PVC) devoid of olefinic structures but could form double bonds during the pyrolysis process was selected particularly. Based on the analysis of thermal behavior, residues with different pyrolysis degrees were prepared under simulated fire conditions using an internationally recognized standard heat source, a cone calorimeter. Qualitative and quantitative analyses were conducted by gas chromatography–mass spectrometry and Pearson product-moment correlation coefficient, respectively. Furthermore, an interpretation of the results was confirmed by thermogravimetric analysis coupled with infrared spectrum. The results showed that the frequently encountered compounds for gasoline identification could be detected in all the PVC residues formed under different pyrolysis conditions. Particularly, for the residues obtained after heating at 300°C for 2 min and 440°C for 7 min, the overall chromatograms profiles presented higher similarity to that of gasoline combustion residues. Based on the results above, it can be concluded that the pyrolysis process cannot be ignored when discussing the matrix interference of one typical matrix since fire conditions are extraordinarily complicated, and moreover the double bonds, which are not involved in molecules inherently but formed during heating due to the typical pyrolysis mechanism of side-group scission in PVC, are considered to be the functional group interfering to ignitable liquid residues identification further. The study provided a novel viewpoint for comprehensively understanding the matrix interference mechanism by combining chemical structure and pyrolysis process together, which can be used to predict and eliminate the impact of matrix interference.</p></div>","PeriodicalId":558,"journal":{"name":"Fire Technology","volume":"61 4","pages":"1701 - 1727"},"PeriodicalIF":2.4,"publicationDate":"2024-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145170171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 High-Temperature Resistant Inclinometers for Structural Displacement Acquisition of the Buildings Subjected to Fire 耐火建筑结构位移测量用耐高温测斜仪的研制

IF 2.4 3区工程技术

Fire Technology Pub Date : 2024-10-23 DOI: 10.1007/s10694-024-01665-y

Jinyu Li, Shaojun Zhu, Wei Ji, Guo-Qiang Li, Yao Wang, Honghui Qi

{"title":"Development of High-Temperature Resistant Inclinometers for Structural Displacement Acquisition of the Buildings Subjected to Fire","authors":"Jinyu Li, Shaojun Zhu, Wei Ji, Guo-Qiang Li, Yao Wang, Honghui Qi","doi":"10.1007/s10694-024-01665-y","DOIUrl":"10.1007/s10694-024-01665-y","url":null,"abstract":"<div><p>Fire significantly challenges the integrity and safety of building structures, as it can drastically reduce the strength and stiffness of constructional materials, especially steel, leading to an increased risk of structural failure. However, it is difficult to monitor the structural behavior effectively as traditional measurement techniques fail easily under fire. In response to this challenge, this study aims to develop a high-temperature resistant inclinometer and to advance the methods for acquiring and predicting structural responses during fire incidents. Through comprehensive testing, including failure analysis of a steel beam in a burning furnace and a real fire test on an actual building, this research validates the high-temperature resistance of the newly developed inclinometer. Besides, the effectiveness of indirect displacement measurement methods is also validated—these methods include polynomial fitting and deep learning algorithms. The study demonstrates that the specially designed inclinometer can operate effectively in high-temperature environments for over an hour, providing critical data for monitoring the safety of structures in fire. The displacements obtained from these indirect methods are vital for detecting potential structural collapses caused by fire, significantly contributing to developing an early-warning system for fire-induced collapse of steel structures.</p></div>","PeriodicalId":558,"journal":{"name":"Fire Technology","volume":"61 4","pages":"1885 - 1914"},"PeriodicalIF":2.4,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145168996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

Evaluation of the Behavior of Composite Double Web-Angle Connections at Ambient Temperature and in a Fire Situation 复合材料双腹板角连接在环境温度和火灾情况下的性能评价

IF 2.4 3区工程技术

Fire Technology Pub Date : 2024-10-22 DOI: 10.1007/s10694-024-01663-0

Renato Silva Nicoletti, Adriano Silva de Carvalho, Alex Sander Clemente de Souza, Saulo José de Castro Almeida

{"title":"Evaluation of the Behavior of Composite Double Web-Angle Connections at Ambient Temperature and in a Fire Situation","authors":"Renato Silva Nicoletti, Adriano Silva de Carvalho, Alex Sander Clemente de Souza, Saulo José de Castro Almeida","doi":"10.1007/s10694-024-01663-0","DOIUrl":"10.1007/s10694-024-01663-0","url":null,"abstract":"<div><p>Steel–concrete composite connections play a crucial role in ensuring the transfer of forces between steel and concrete structural elements. Additionally, the safety of structures during fire incidents has gained significant attention worldwide. This study focuses on investigating the behavior of composite double web-angle connections under ambient temperature and fire conditions using numerical analysis. After adjusting the numerical models, a parametric analysis was conducted. The results revealed that the composite double web-angle connections exhibited semi-rigid behavior at ambient temperature. Moreover, the fire event altered the failure mechanism of the connections. A negative reinforcement rate of 0.75% resulted in the maximum stiffness at room temperature and the biggest variance in rotational capacity under a fire condition, according to the parametric analysis. Furthermore, parameters such as slab type, steel–concrete interaction, bending moment direction, and steel and concrete strength all had a substantial impact on the behavior of the connections under both ambient and fire circumstances. This paper also includes practical formulae for determining the moment resistance and starting stiffness at ambient temperature, as well as the lowered stiffness during a fire and the cumulative variance in rotational capacity for composite double web-angle connections.</p></div>","PeriodicalId":558,"journal":{"name":"Fire Technology","volume":"61 4","pages":"1809 - 1860"},"PeriodicalIF":2.4,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145168942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

Impact of Airflow Rate on Fire Suppression via Water Mist in a Mechanically Ventilated Compartment 机械通风舱内气流速率对水雾灭火的影响

IF 2.4 3区工程技术

Fire Technology Pub Date : 2024-10-18 DOI: 10.1007/s10694-024-01654-1

Lahna Acherar, Hui-Ying Wang, Bruno Coudour, Jean Pierre Garo

{"title":"Impact of Airflow Rate on Fire Suppression via Water Mist in a Mechanically Ventilated Compartment","authors":"Lahna Acherar, Hui-Ying Wang, Bruno Coudour, Jean Pierre Garo","doi":"10.1007/s10694-024-01654-1","DOIUrl":"10.1007/s10694-024-01654-1","url":null,"abstract":"<div><p>This study demonstrates how or whether an inlet vent rate affects flame suppression behaviour in highly confined and mechanically ventilated installations which are a typical hazard in the nuclear safety area. The primary objective of the present work is to provide a detailed experimental study on fire suppression phenomena via water mist in a buoyant, turbulent diffusion flame representing the key characteristics of a realistic fire. From the present work, it is found that water mist application in a hot confined environment allows to achieve maximum droplet evaporation in the smoke layer near the ceiling. As a result, the mist can’t be transported to the fire source during the fire-water interaction period. Reduction in flame-to-wall radiation heat transfer via cooling of smoke layer by water mist over liquid surface does not conduct to suppression of a confined fully developed fire. Through the analysis on Heat Release Rate (HRR), gas temperature, heat flux and chemical species, it is concluded that in a hot environment, a consecutive efficient cooling of the smoke layer thanks to a strong droplet evaporation leads to the fire suppression only with Air Change Per Hour (ACPH) below 28 via lack of oxygen.</p></div>","PeriodicalId":558,"journal":{"name":"Fire Technology","volume":"61 4","pages":"1557 - 1578"},"PeriodicalIF":2.4,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145167349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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