Pub Date : 1900-01-01DOI: 10.2749/nanjing.2022.2039
Zhibo Teng
In the research process of bridge-CAD, through the analysis of the results from penman’s new concept for bridge triunity, it is concluded that the essence of beauty is compassion originally being “karun!a” in Sanskrit, and this conclusion is primarily verified. This study is of positive significance to the cultural self-confidence of Chinese nation.
{"title":"Compassion: Essence of Beauty from Triunity of Bridge-CAD","authors":"Zhibo Teng","doi":"10.2749/nanjing.2022.2039","DOIUrl":"https://doi.org/10.2749/nanjing.2022.2039","url":null,"abstract":"In the research process of bridge-CAD, through the analysis of the results from penman’s new concept for bridge triunity, it is concluded that the essence of beauty is compassion originally being “karun!a” in Sanskrit, and this conclusion is primarily verified. This study is of positive significance to the cultural self-confidence of Chinese nation.","PeriodicalId":410450,"journal":{"name":"IABSE Congress, Nanjing 2022: Bridges and Structures: Connection, Integration and Harmonisation","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128146682","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}
Pub Date : 1900-01-01DOI: 10.2749/nanjing.2022.1103
Junlen Zhang
The water-stopping efficiency of cofferdams for pile caps is an important indicator with direct influ- ence to the quality and durability of the pile-pouring process. In recent years, a new technique fea- turing flexible capsules serving as waterstops has been introduced, but is still in experimental stage. This thesis, taking the water-stopping construction programme of underwater PC houses of the J. P. Magufuli Bridge project in Tanzania as background, analyzed the two existed types of flexible water- stopping construction methods, id est the integral and separate structures, and studied on measures for improving the flexible water-stopping construction techniques and optimizing the rubber cap- sule waterstops, in the hope of providing references and, possibly, inspirations for similar projects in the future.
承台围堰的止水效率是一项重要指标，直接影响到浇筑过程的质量和耐久性。近年来，人们提出了一种柔性胶囊作为止水带的新技术，但仍处于试验阶段。本文以坦桑尼亚J. P. Magufuli大桥水下PC屋止水施工方案为背景，分析了现有的两种柔性止水施工方法，对整体结构和分体式结构进行了测试，研究了改进柔性止水施工技术和优化橡胶帽壳止水的措施，以期为今后的工程建设提供参考。对未来类似项目的启发。
{"title":"Construction of Flexible Waterstops on Underwater Cofferdams for Pile Caps in Bridge Projects","authors":"Junlen Zhang","doi":"10.2749/nanjing.2022.1103","DOIUrl":"https://doi.org/10.2749/nanjing.2022.1103","url":null,"abstract":"The water-stopping efficiency of cofferdams for pile caps is an important indicator with direct influ- ence to the quality and durability of the pile-pouring process. In recent years, a new technique fea- turing flexible capsules serving as waterstops has been introduced, but is still in experimental stage. This thesis, taking the water-stopping construction programme of underwater PC houses of the J. P. Magufuli Bridge project in Tanzania as background, analyzed the two existed types of flexible water- stopping construction methods, id est the integral and separate structures, and studied on measures for improving the flexible water-stopping construction techniques and optimizing the rubber cap- sule waterstops, in the hope of providing references and, possibly, inspirations for similar projects in the future.","PeriodicalId":410450,"journal":{"name":"IABSE Congress, Nanjing 2022: Bridges and Structures: Connection, Integration and Harmonisation","volume":"129 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133720229","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}
Pub Date : 1900-01-01DOI: 10.2749/nanjing.2022.0267
Guang Hong, Jiawu Li, Jiaying Wang, Jun Wang, Feng Wang, Yu Li
The paper researches the wind vibration performance of suspended double-deck streamlined bridge deck using the wind tunnel test and numerical simulation. Studies shown that for suspended double- deck bridge, due to the aerodynamic interference of the upper deck, the lower deck is driven by a vertical vibration negative damping, and the vertical vibration is significantly changed. The pressure distribution of the upper deck and the upper edge of lower deck did not change. The wind load acts on the upper edge of lower deck, and the minus attack angle was generated. With the generation, migration and shedding of large-scale vortices at the lower edge of the lower deck, the lower deck occurs the bending-torsional coupling "soft flutter". Moreover, due to the structural static coupling between the upper deck and the lower deck, the bending-torsional soft flutter at the lower deck induces the bending-torsional soft flutter of the double-deck bridge deck.
{"title":"Wind Induced Vibration Performance of Suspended Double-deck Flat Box Girder Bridge","authors":"Guang Hong, Jiawu Li, Jiaying Wang, Jun Wang, Feng Wang, Yu Li","doi":"10.2749/nanjing.2022.0267","DOIUrl":"https://doi.org/10.2749/nanjing.2022.0267","url":null,"abstract":"The paper researches the wind vibration performance of suspended double-deck streamlined bridge deck using the wind tunnel test and numerical simulation. Studies shown that for suspended double- deck bridge, due to the aerodynamic interference of the upper deck, the lower deck is driven by a vertical vibration negative damping, and the vertical vibration is significantly changed. The pressure distribution of the upper deck and the upper edge of lower deck did not change. The wind load acts on the upper edge of lower deck, and the minus attack angle was generated. With the generation, migration and shedding of large-scale vortices at the lower edge of the lower deck, the lower deck occurs the bending-torsional coupling \"soft flutter\". Moreover, due to the structural static coupling between the upper deck and the lower deck, the bending-torsional soft flutter at the lower deck induces the bending-torsional soft flutter of the double-deck bridge deck.","PeriodicalId":410450,"journal":{"name":"IABSE Congress, Nanjing 2022: Bridges and Structures: Connection, Integration and Harmonisation","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134079117","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}
Pub Date : 1900-01-01DOI: 10.2749/nanjing.2022.0249
Xin Zhao, Yuzhou Hou, Jianan Chen, Yutong Xu
The wind induced response of the steel tall building is obvious. Controlling the wind induced response of steel tall building can effectively improve the comfort, stiffness and strength performance of the structure. A large number of studies have shown that equipping damping device is a more effective wind-induced vibration control measure than increasing the structure stiffness. Viscous damps can achieve multi-load and multi-performance structure vibration reduction and have a very broad engineering application prospect. In this paper, the wind induced response of steel tall building and the viscous damper system are studied to ascertain the optimal arrangement and quantity of viscous damps and a 150m steel residential tower is taken as an engineering case, which shows that the integrated viscous damps can effectively improve the structure performance of steel tall building under wind load and reduce the steel consumption of the structure.
{"title":"Wind Induced Response Analysis and Vibration Mitigation Design for Steel Tall Buildings Equipped with Viscous Dampers","authors":"Xin Zhao, Yuzhou Hou, Jianan Chen, Yutong Xu","doi":"10.2749/nanjing.2022.0249","DOIUrl":"https://doi.org/10.2749/nanjing.2022.0249","url":null,"abstract":"The wind induced response of the steel tall building is obvious. Controlling the wind induced response of steel tall building can effectively improve the comfort, stiffness and strength performance of the structure. A large number of studies have shown that equipping damping device is a more effective wind-induced vibration control measure than increasing the structure stiffness. Viscous damps can achieve multi-load and multi-performance structure vibration reduction and have a very broad engineering application prospect. In this paper, the wind induced response of steel tall building and the viscous damper system are studied to ascertain the optimal arrangement and quantity of viscous damps and a 150m steel residential tower is taken as an engineering case, which shows that the integrated viscous damps can effectively improve the structure performance of steel tall building under wind load and reduce the steel consumption of the structure.","PeriodicalId":410450,"journal":{"name":"IABSE Congress, Nanjing 2022: Bridges and Structures: Connection, Integration and Harmonisation","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125227133","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}
Pub Date : 1900-01-01DOI: 10.2749/nanjing.2022.0126
Jinping Zhang, J. Marcussen, J. W. Sørensen, Assad Jamal
From 20th century, infrastructure in China has experienced rapid development, especially in mega cable supported bridges. COWI had the honour and opportunity to participate in some of the prestigious mega bridge/sea crossing projects, and thus gained in-depth knowledge in the bridge design following Chinese traditions. The mutual corporation on these projects between COWI and the Chinese designers as well as Chinese project owners has closed the knowledge gap of design and construction methods by Chinese tradition and Danish tradition, and also enhanced the technical development and know-how of modern bridge design.In this paper, some of the challenging issues for mega suspension bridges are presented, where the Chinese way and Danish way in addressing aerodynamic flutter stability, design of hanger system, and anchor block & foundation are described and discussed.
{"title":"COWI Experiences in Chinese Mega Bridge Projects – Danish Way and Chinese Way","authors":"Jinping Zhang, J. Marcussen, J. W. Sørensen, Assad Jamal","doi":"10.2749/nanjing.2022.0126","DOIUrl":"https://doi.org/10.2749/nanjing.2022.0126","url":null,"abstract":"From 20th century, infrastructure in China has experienced rapid development, especially in mega cable supported bridges. COWI had the honour and opportunity to participate in some of the prestigious mega bridge/sea crossing projects, and thus gained in-depth knowledge in the bridge design following Chinese traditions. The mutual corporation on these projects between COWI and the Chinese designers as well as Chinese project owners has closed the knowledge gap of design and construction methods by Chinese tradition and Danish tradition, and also enhanced the technical development and know-how of modern bridge design.In this paper, some of the challenging issues for mega suspension bridges are presented, where the Chinese way and Danish way in addressing aerodynamic flutter stability, design of hanger system, and anchor block & foundation are described and discussed.","PeriodicalId":410450,"journal":{"name":"IABSE Congress, Nanjing 2022: Bridges and Structures: Connection, Integration and Harmonisation","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134205663","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}
Pub Date : 1900-01-01DOI: 10.2749/nanjing.2022.1465
T. Takai, Kenshin Tanii
Bolted connection is one of the well-used techniques to connect structural members of steel bridges. Not only load capacity but also energy absorption are important characteristics of the structure to resist seismic action. In a finite element analysis, a true stress-true strain material model is needed to obtain an accurate evaluation in case the structure is exposed to excessive forces and deformed largely, although the true stress-true strain model is almost the same as to nominal stress-strain model in the small strain part. This study proposes a simple true stress-true strain model. And, the validity of the model was confirmed by the compare the finite element analysis and steel material tensile test or tensile experiment of bolted connection. Some true stress-true strain models were investigated and discussed from the viewpoint of load capacity and energy absorption.
{"title":"Stress-strain Model Adapted to Bolted Connection in Ultimate Behaviour Considering Energy Absorption","authors":"T. Takai, Kenshin Tanii","doi":"10.2749/nanjing.2022.1465","DOIUrl":"https://doi.org/10.2749/nanjing.2022.1465","url":null,"abstract":"Bolted connection is one of the well-used techniques to connect structural members of steel bridges. Not only load capacity but also energy absorption are important characteristics of the structure to resist seismic action. In a finite element analysis, a true stress-true strain material model is needed to obtain an accurate evaluation in case the structure is exposed to excessive forces and deformed largely, although the true stress-true strain model is almost the same as to nominal stress-strain model in the small strain part. This study proposes a simple true stress-true strain model. And, the validity of the model was confirmed by the compare the finite element analysis and steel material tensile test or tensile experiment of bolted connection. Some true stress-true strain models were investigated and discussed from the viewpoint of load capacity and energy absorption.","PeriodicalId":410450,"journal":{"name":"IABSE Congress, Nanjing 2022: Bridges and Structures: Connection, Integration and Harmonisation","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134229500","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}
Pub Date : 1900-01-01DOI: 10.2749/nanjing.2022.0258
Dongzhou Huang, Yicheng Huang
The objective of this paper is to summarize current theory, design, and construction methods of concrete segmental girder bridges and to propose future research needs. First, the analytical theory will be overviewed, including concrete creep and shrinkage, bending strength with external tendons and unbounded tendons, web crack control, anchorage, etc. Then, the paper covers design methods regarding corrosion, including the use of Electrically Isolated Tendons (EIT) system, Fiber Reinforced Polymer (FRP) tendons and other corrosion protection techniques. In addition, internal redundance; the use of ultra-high-performance concrete (UHPC); and standardization for expediting the concrete segmental bridge design will be presented. The paper concludes with a discussion of research needs for future development of concrete segmental bridges.
{"title":"State of the Art of Concrete Segmental Bridges","authors":"Dongzhou Huang, Yicheng Huang","doi":"10.2749/nanjing.2022.0258","DOIUrl":"https://doi.org/10.2749/nanjing.2022.0258","url":null,"abstract":"The objective of this paper is to summarize current theory, design, and construction methods of concrete segmental girder bridges and to propose future research needs. First, the analytical theory will be overviewed, including concrete creep and shrinkage, bending strength with external tendons and unbounded tendons, web crack control, anchorage, etc. Then, the paper covers design methods regarding corrosion, including the use of Electrically Isolated Tendons (EIT) system, Fiber Reinforced Polymer (FRP) tendons and other corrosion protection techniques. In addition, internal redundance; the use of ultra-high-performance concrete (UHPC); and standardization for expediting the concrete segmental bridge design will be presented. The paper concludes with a discussion of research needs for future development of concrete segmental bridges.","PeriodicalId":410450,"journal":{"name":"IABSE Congress, Nanjing 2022: Bridges and Structures: Connection, Integration and Harmonisation","volume":"147 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134177507","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}
Pub Date : 1900-01-01DOI: 10.2749/nanjing.2022.1521
Xudong Jian, XinHong Liu, Jiwei Zhong, Yafei Wang, Ye Xia
Indirect identification of bridge frequencies, which refers to identifying bridge frequencies from the dynamic responses of a vehicle moving or stopping on the bridge, has the potential to fast inspect bridges in large quantities. Although there have been extensive studies on this topic, most of them are built on theoretic analysis or numerical simulation, which could differ from the situations in real practice. As a complement, this study carries out an experimental investigation of the indirect approach for bridge frequency identification. In the experiments, a normal passenger car instrumented with accelerometers moves and stops on a real bridge for indirect sensing, and a stationary accelerometer is directly deployed on the bridge as a control. Experimental results provide some new insights into the indirect bridge frequency identification from the practical aspect.
{"title":"An Experimental Investigation of the Indirect Bridge Frequency Identification","authors":"Xudong Jian, XinHong Liu, Jiwei Zhong, Yafei Wang, Ye Xia","doi":"10.2749/nanjing.2022.1521","DOIUrl":"https://doi.org/10.2749/nanjing.2022.1521","url":null,"abstract":"Indirect identification of bridge frequencies, which refers to identifying bridge frequencies from the dynamic responses of a vehicle moving or stopping on the bridge, has the potential to fast inspect bridges in large quantities. Although there have been extensive studies on this topic, most of them are built on theoretic analysis or numerical simulation, which could differ from the situations in real practice. As a complement, this study carries out an experimental investigation of the indirect approach for bridge frequency identification. In the experiments, a normal passenger car instrumented with accelerometers moves and stops on a real bridge for indirect sensing, and a stationary accelerometer is directly deployed on the bridge as a control. Experimental results provide some new insights into the indirect bridge frequency identification from the practical aspect.","PeriodicalId":410450,"journal":{"name":"IABSE Congress, Nanjing 2022: Bridges and Structures: Connection, Integration and Harmonisation","volume":"782 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132073662","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}
Pub Date : 1900-01-01DOI: 10.2749/nanjing.2022.0291
Dewang Li, Huating Chen, Wenxue Zhang, X. Zhu
Rail-cum-road truss bridges are rapidly developing, and frequent cracking in freshly poured deck concrete is of great concern. For the performance of such a load-bearing deck, it is necessary to understand its stress status due to short-term shrinkage. Taking a newly-constructed rail-cum-road truss bridge as the case project, this paper, by ANSYS finite element simulation, mainly analyzed the stress distribution in deck concrete under short-term action of shrinkage. Shrinkage of one deck panel and two companion specimens shortly after the concrete pouring was measured through in- situ testing. It was found that the free shrinkage of companion specimens at 40 days is 140~150 micro strains, significantly higher than that indicated by the current code. Under the action of short- term shrinkage, tensile shrinkage stress in the magnitude of 1,5~3,5 MPa is present in the deck, triggering potential cracking, and its effect shall therefore not be neglected.
{"title":"Effect of Short-Term Shrinkage on Deck Concrete of a Rail-Cum-Road Composite Truss Bridge","authors":"Dewang Li, Huating Chen, Wenxue Zhang, X. Zhu","doi":"10.2749/nanjing.2022.0291","DOIUrl":"https://doi.org/10.2749/nanjing.2022.0291","url":null,"abstract":"Rail-cum-road truss bridges are rapidly developing, and frequent cracking in freshly poured deck concrete is of great concern. For the performance of such a load-bearing deck, it is necessary to understand its stress status due to short-term shrinkage. Taking a newly-constructed rail-cum-road truss bridge as the case project, this paper, by ANSYS finite element simulation, mainly analyzed the stress distribution in deck concrete under short-term action of shrinkage. Shrinkage of one deck panel and two companion specimens shortly after the concrete pouring was measured through in- situ testing. It was found that the free shrinkage of companion specimens at 40 days is 140~150 micro strains, significantly higher than that indicated by the current code. Under the action of short- term shrinkage, tensile shrinkage stress in the magnitude of 1,5~3,5 MPa is present in the deck, triggering potential cracking, and its effect shall therefore not be neglected.","PeriodicalId":410450,"journal":{"name":"IABSE Congress, Nanjing 2022: Bridges and Structures: Connection, Integration and Harmonisation","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132492160","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}
Pub Date : 1900-01-01DOI: 10.2749/nanjing.2022.0199
A. Larsen, J. W. Sørensen
The aerodynamics of the twin-box bridge is considered to highlight the reasons for making this type of bridge deck superior to the conventional trapezoidal mono-box for suspension bridges having span lengths longer than 1800 m. The paper proposes a simple theoretical model yielding physical insight into the flutter stability and presents a design example comparing the flutter performance of a 2000 m main span suspension bridge designed with either a mono-box or a twin-box bridge girder. Experience from vortex induced vibration of twin-box bridges is discussed to demonstrate that a twin-box girder can be designed to avoid vortex induced for practical damping levels.
{"title":"Benefits and Challenges of the Twin-box Bridge Girder","authors":"A. Larsen, J. W. Sørensen","doi":"10.2749/nanjing.2022.0199","DOIUrl":"https://doi.org/10.2749/nanjing.2022.0199","url":null,"abstract":"The aerodynamics of the twin-box bridge is considered to highlight the reasons for making this type of bridge deck superior to the conventional trapezoidal mono-box for suspension bridges having span lengths longer than 1800 m. The paper proposes a simple theoretical model yielding physical insight into the flutter stability and presents a design example comparing the flutter performance of a 2000 m main span suspension bridge designed with either a mono-box or a twin-box bridge girder. Experience from vortex induced vibration of twin-box bridges is discussed to demonstrate that a twin-box girder can be designed to avoid vortex induced for practical damping levels.","PeriodicalId":410450,"journal":{"name":"IABSE Congress, Nanjing 2022: Bridges and Structures: Connection, Integration and Harmonisation","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131832434","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：