Li Zhongyu, Yu. G. Aliakseyeu, Zhang Qing, A. Bubulis, V. Minchenya, Shi Jicun, A. Romanov, Aliaksandr Khadasevich, Ivan Charnabai
The technique of determining the pavement layers strength are given. The results of a field (on the road) testing of asphalt concrete Highway pavement using georadar vibration-acoustic set of equipment are presented. The hardware complex is proved and developed for the automobile roads express-control. Functioning of hardware complex and technique for pavement layer durability definition are described. The ways of the further perfection for the georadar vibrating-acoustic technology are considered.
{"title":"Georadar vibration-acoustic technology for express-control of road pavement strength and results of its application","authors":"Li Zhongyu, Yu. G. Aliakseyeu, Zhang Qing, A. Bubulis, V. Minchenya, Shi Jicun, A. Romanov, Aliaksandr Khadasevich, Ivan Charnabai","doi":"10.21595/JME.2019.20237","DOIUrl":"https://doi.org/10.21595/JME.2019.20237","url":null,"abstract":"The technique of determining the pavement layers strength are given. The results of a field (on the road) testing of asphalt concrete Highway pavement using georadar vibration-acoustic set of equipment are presented. The hardware complex is proved and developed for the automobile roads express-control. Functioning of hardware complex and technique for pavement layer durability definition are described. The ways of the further perfection for the georadar vibrating-acoustic technology are considered.","PeriodicalId":42196,"journal":{"name":"Journal of Measurements in Engineering","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2019-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44124218","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}
This paper presents evaluation of vibroacoustical requirements in the context of impact and airborne sound insulation in hotel building. This building represents traditional wooden architecture present in southern Poland. Similar structures can be found all around Europe in mountainous areas. Due to fact that there are little information about acoustic conditions of such buildings, this paper gives measured values of sound insulation of typical solutions used in this architecture. In order to define if requirements of current polish standard PN-B-02151-03:2015 for hotel buildings are met, impact sound level and airborne sound insulation of representative partitions were measured. Measurement conducted in presented building shows issues connected with non-sufficient airborne sound insulation of internal partitions – timber log walls. Due to its low mass and, in simplification, homogenous structure, its sound insulation is far from meeting requirements. Considering timber structural ceiling and reinforced concrete floor present in hotel building requirements of impact sound level and airborne sound insulation are met. The solution of weak acoustic conditions of walls is proposed as plasterboard pre-wall with mineral wool inside.
本文介绍了酒店建筑在冲击和空气隔声条件下的振动声学要求评价。这座建筑代表了波兰南部传统的木制建筑。类似的结构可以在欧洲各地的山区找到。由于此类建筑的声学条件信息很少，本文给出了该建筑中典型解决方案的隔声测量值。为了确定是否满足酒店建筑现行波兰标准pn - b -02151- 03:15的要求，对代表性隔墙的冲击声级和空气隔声进行了测量。在所展示的建筑中进行的测量显示，内部隔墙-原木墙的空气隔音不足。由于其质量小，结构单一，隔声性能远不能满足要求。考虑到酒店建筑现有的木结构吊顶和钢筋混凝土楼板，满足了冲击声级和空气隔声的要求。针对墙体弱声条件，提出采用石膏板预墙内加矿棉的解决方案。
{"title":"Analysis of acoustic insulation in traditional wooden architecture hotel building","authors":"K. Nering, B. Ziarko, K. Stypuła","doi":"10.21595/JME.2019.20448","DOIUrl":"https://doi.org/10.21595/JME.2019.20448","url":null,"abstract":"This paper presents evaluation of vibroacoustical requirements in the context of impact and airborne sound insulation in hotel building. This building represents traditional wooden architecture present in southern Poland. Similar structures can be found all around Europe in mountainous areas. Due to fact that there are little information about acoustic conditions of such buildings, this paper gives measured values of sound insulation of typical solutions used in this architecture. In order to define if requirements of current polish standard PN-B-02151-03:2015 for hotel buildings are met, impact sound level and airborne sound insulation of representative partitions were measured. Measurement conducted in presented building shows issues connected with non-sufficient airborne sound insulation of internal partitions – timber log walls. Due to its low mass and, in simplification, homogenous structure, its sound insulation is far from meeting requirements. Considering timber structural ceiling and reinforced concrete floor present in hotel building requirements of impact sound level and airborne sound insulation are met. The solution of weak acoustic conditions of walls is proposed as plasterboard pre-wall with mineral wool inside.","PeriodicalId":42196,"journal":{"name":"Journal of Measurements in Engineering","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2019-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47825834","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}
This paper describes the soil-structure interaction (SSI) effects to the Nuclear Power Plant (NPP) structure with reactor VVER-1200/491 PWR. The simplified 1D and numerical 3D FE models of the layered subsoil are investigated. The methodology of the calculation of the frequency dependent complex functions of the soil stiffness and damping is presented.
{"title":"Dynamic analysis of soil-structure interaction effects on NPP building using simplified and solid FE model of layered subsoil","authors":"J. Králik","doi":"10.21595/JME.2019.20423","DOIUrl":"https://doi.org/10.21595/JME.2019.20423","url":null,"abstract":"This paper describes the soil-structure interaction (SSI) effects to the Nuclear Power Plant (NPP) structure with reactor VVER-1200/491 PWR. The simplified 1D and numerical 3D FE models of the layered subsoil are investigated. The methodology of the calculation of the frequency dependent complex functions of the soil stiffness and damping is presented.","PeriodicalId":42196,"journal":{"name":"Journal of Measurements in Engineering","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2019-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42417469","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}
The reinforcement of existing masonry vaults against seismic actions is an extremely timing issue and it has already involved many researchers in experimental testing and numerical modelling. However, up to now, the results of the research have been expressed and compared in terms of load-displacement capacity curves. But the designers, in the practice, need to assess the resisting peak ground acceleration of the vault (PGA), so to compare it with the seismic demand. In the paper, a strategy to evaluate this parameter, based on the modified Capacity Spectrum Method and accounting for the level of the vault in the building is proposed. The procedure is applied to a case study of a masonry building with barrel vaults, comparing the performances of plain vaults and vaults strengthened with a GFRP (Glass Fiber Reinforced Polymer) reinforced mortar coating. The results evidenced significant improvements in terms of PGA after the reinforcement, attaining to values from 3.1 to 3.3 times that of the unreinforced vault.
{"title":"Masonry vaults strengthened with a GFRP reinforced mortar coating: evaluation of the resisting peak ground acceleration","authors":"N. Gattesco, I. Boem","doi":"10.21595/JME.2018.20409","DOIUrl":"https://doi.org/10.21595/JME.2018.20409","url":null,"abstract":"The reinforcement of existing masonry vaults against seismic actions is an extremely timing issue and it has already involved many researchers in experimental testing and numerical modelling. However, up to now, the results of the research have been expressed and compared in terms of load-displacement capacity curves. But the designers, in the practice, need to assess the resisting peak ground acceleration of the vault (PGA), so to compare it with the seismic demand. In the paper, a strategy to evaluate this parameter, based on the modified Capacity Spectrum Method and accounting for the level of the vault in the building is proposed. The procedure is applied to a case study of a masonry building with barrel vaults, comparing the performances of plain vaults and vaults strengthened with a GFRP (Glass Fiber Reinforced Polymer) reinforced mortar coating. The results evidenced significant improvements in terms of PGA after the reinforcement, attaining to values from 3.1 to 3.3 times that of the unreinforced vault.","PeriodicalId":42196,"journal":{"name":"Journal of Measurements in Engineering","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2018-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47947128","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}
Grandstands are structures which are regularly subjected to dynamic loads generated by crowd motions. It is a dangerous situation when spectators induce rhythmic jumping, dancing, stamping, etc. If the synchronized movement of spectators excites a natural frequency of the structure, resonant response might occur. To avoid such situations, temporary steel grandstands are commonly strengthened using additional elements that create bracing system which is selected depending on the size of the structure, type of the event, acting load, etc. It was proved that not only the use but also the arrangement of such structural members is crucial for the dynamic structural resistance. The aim of the present study is to determine the most effective arrangement of bracing system for a typical example of the temporary steel grandstand which is exposed to dynamic load induced by spectators. Three different arrangements of bracing systems have been analysed using five criteria recommended in the literature. The results of the study clearly show that the dynamic parameters of the grandstand are substantially different for various types of bracing systems. The largest improvement in the structural behaviour has been obtained for the grandstand equipped with the bracing system satisfying all proposed criteria. The peak accelerations for this case have been found to be nearly twice as low as for structures with other bracing arrangements. The application of such a system for the grandstand which is exposed to human-induced vibrations allows for safe use of the structure as well as improves comfort of spectators.
{"title":"Analysis of temporary steel grandstand with different bracing systems exposed to crowd load","authors":"N. Lasowicz, T. Falborski, R. Jankowski","doi":"10.21595/JME.2018.20422","DOIUrl":"https://doi.org/10.21595/JME.2018.20422","url":null,"abstract":"Grandstands are structures which are regularly subjected to dynamic loads generated by crowd motions. It is a dangerous situation when spectators induce rhythmic jumping, dancing, stamping, etc. If the synchronized movement of spectators excites a natural frequency of the structure, resonant response might occur. To avoid such situations, temporary steel grandstands are commonly strengthened using additional elements that create bracing system which is selected depending on the size of the structure, type of the event, acting load, etc. It was proved that not only the use but also the arrangement of such structural members is crucial for the dynamic structural resistance. The aim of the present study is to determine the most effective arrangement of bracing system for a typical example of the temporary steel grandstand which is exposed to dynamic load induced by spectators. Three different arrangements of bracing systems have been analysed using five criteria recommended in the literature. The results of the study clearly show that the dynamic parameters of the grandstand are substantially different for various types of bracing systems. The largest improvement in the structural behaviour has been obtained for the grandstand equipped with the bracing system satisfying all proposed criteria. The peak accelerations for this case have been found to be nearly twice as low as for structures with other bracing arrangements. The application of such a system for the grandstand which is exposed to human-induced vibrations allows for safe use of the structure as well as improves comfort of spectators.","PeriodicalId":42196,"journal":{"name":"Journal of Measurements in Engineering","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2018-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43452647","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}
Human-induced vibration has become a serious serviceability problem due to the larger opening of girder, lighter floor systems and longer spans designed and used in practice. Vibration tests were undertaken in laboratory to research the vibrational characteristics of the arch pre-stressed concrete truss (APT) system spanning 16.0 m. Results from ambient vibration, impulse excitations (heel-drop and jumping) and steady-state incentives (walking and running) were presented. Dynamic characteristics such as natural frequencies, damping ratios, mode shapes and acceleration responses were studied and checked against the existing codes. Experimental results show that the investigated APT girder possesses high fundamental frequency and low damping ratio. Moreover, the perception factors based on the root-mean-square acceleration, vibration dose value (VDV) and psychological comfort data were obtained. Lastly, the threshold accelerations and VDVs were suggested for evaluating the human-induced vibration.
{"title":"Human-induced vibration serviceability of arch pre-stressed concrete truss system","authors":"Xu-hong Zhou, Qingshan Yang, Jiang Li, Xiao-Bo Ma","doi":"10.21595/JME.2018.20424","DOIUrl":"https://doi.org/10.21595/JME.2018.20424","url":null,"abstract":"Human-induced vibration has become a serious serviceability problem due to the larger opening of girder, lighter floor systems and longer spans designed and used in practice. Vibration tests were undertaken in laboratory to research the vibrational characteristics of the arch pre-stressed concrete truss (APT) system spanning 16.0 m. Results from ambient vibration, impulse excitations (heel-drop and jumping) and steady-state incentives (walking and running) were presented. Dynamic characteristics such as natural frequencies, damping ratios, mode shapes and acceleration responses were studied and checked against the existing codes. Experimental results show that the investigated APT girder possesses high fundamental frequency and low damping ratio. Moreover, the perception factors based on the root-mean-square acceleration, vibration dose value (VDV) and psychological comfort data were obtained. Lastly, the threshold accelerations and VDVs were suggested for evaluating the human-induced vibration.","PeriodicalId":42196,"journal":{"name":"Journal of Measurements in Engineering","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2018-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45973881","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}
Dynamic measurements of two steel truss bridges for Structural Health Monitoring (SHM) were performed. The investigated bridges were: a single supported one span truss bridge and a multi-span truss bridge. Two possibilities of measuring setup were considered. A simple arrangement made up of one polygon has been used for data acquisition of the single span truss bridge. A more complex measuring setup made up of two polygons with up to 32 channels has been used for the large bridge with an entire length reaching up to 500 m. A connection of both measuring polygons was achieved by Wi-Fi antennas. The reason why the multi-span truss bridge was chosen for SHM is that the construction is nowadays overloaded. The dynamic measurements were done, ambient and semi-ambient data were analysed. After that, some mode-shapes were identified from the acquired data and then the data were compared with numerical calculations. Finally, experiences and conclusions from the ambient data measurement are summarized.
{"title":"Ambient vibration measurements of steel truss bridges","authors":"M. Venglár, M. Sokol, R. Ároch","doi":"10.21595/JME.2018.20419","DOIUrl":"https://doi.org/10.21595/JME.2018.20419","url":null,"abstract":"Dynamic measurements of two steel truss bridges for Structural Health Monitoring (SHM) were performed. The investigated bridges were: a single supported one span truss bridge and a multi-span truss bridge. Two possibilities of measuring setup were considered. A simple arrangement made up of one polygon has been used for data acquisition of the single span truss bridge. A more complex measuring setup made up of two polygons with up to 32 channels has been used for the large bridge with an entire length reaching up to 500 m. A connection of both measuring polygons was achieved by Wi-Fi antennas. The reason why the multi-span truss bridge was chosen for SHM is that the construction is nowadays overloaded. The dynamic measurements were done, ambient and semi-ambient data were analysed. After that, some mode-shapes were identified from the acquired data and then the data were compared with numerical calculations. Finally, experiences and conclusions from the ambient data measurement are summarized.","PeriodicalId":42196,"journal":{"name":"Journal of Measurements in Engineering","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2018-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42418106","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}
This paper provides the formulation of the problem of forced vibrations of structures, which has the following peculiarities: equations of motion are formulated in absolute coordinates allowing to take into account the asynchronous excitations of the supports, smoothing of the time functions for forced displacements with the help of Hermite polynomials, and also the possibility of considering damping that does not obey the Rayleigh hypothesis.
{"title":"Time history analysis formulation in SCAD FEA software","authors":"S. Fialko, Viktor Karpilovskyi","doi":"10.21595/JME.2018.20408","DOIUrl":"https://doi.org/10.21595/JME.2018.20408","url":null,"abstract":"This paper provides the formulation of the problem of forced vibrations of structures, which has the following peculiarities: equations of motion are formulated in absolute coordinates allowing to take into account the asynchronous excitations of the supports, smoothing of the time functions for forced displacements with the help of Hermite polynomials, and also the possibility of considering damping that does not obey the Rayleigh hypothesis.","PeriodicalId":42196,"journal":{"name":"Journal of Measurements in Engineering","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2018-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45471836","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}
The paper deals with the stability of earth dams subjected to seismic and paraseismic excitations occurring in the close distance to the dam. The Newmark’s stability approach, classified as a simplified dynamic method, has been extended for two directional dynamic loading case and the evolution of the friction coefficient. The paper is focused on the experimental verification of the proposed method for harmonic and cyclic excitations generated by a simple oscillating device as well as by one-directional shaking table. Main assumptions of the proposed method have been proved and the effect of the vertical acceleration on the stability of the dam has been demonstrated. In the experiments conducted under cyclic loading, the impact of the vertical acceleration on the permanent displacement of the block was equal to 57 %. However, in general, the exact magnitude of this impact depends on many factors, such as the vertical to horizontal peak ground acceleration ratio or frequency range of the vertical component of the earthquake.
{"title":"Experimental study of the effect of vertical acceleration component on the slope stability","authors":"A. Korzec, R. Jankowski","doi":"10.21595/JME.2018.20420","DOIUrl":"https://doi.org/10.21595/JME.2018.20420","url":null,"abstract":"The paper deals with the stability of earth dams subjected to seismic and paraseismic excitations occurring in the close distance to the dam. The Newmark’s stability approach, classified as a simplified dynamic method, has been extended for two directional dynamic loading case and the evolution of the friction coefficient. The paper is focused on the experimental verification of the proposed method for harmonic and cyclic excitations generated by a simple oscillating device as well as by one-directional shaking table. Main assumptions of the proposed method have been proved and the effect of the vertical acceleration on the stability of the dam has been demonstrated. In the experiments conducted under cyclic loading, the impact of the vertical acceleration on the permanent displacement of the block was equal to 57 %. However, in general, the exact magnitude of this impact depends on many factors, such as the vertical to horizontal peak ground acceleration ratio or frequency range of the vertical component of the earthquake.","PeriodicalId":42196,"journal":{"name":"Journal of Measurements in Engineering","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2018-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46075699","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}
This paper presents the refined technique of dynamic calculations for suspension earthquake-resistant building. The improved design schemes of suspension buildings and structures have been demonstrated. Two versions of suspension buildings have been analysed. For the system with the building as a point mass suspension on the fixed bearing frame thread, a system of Lagrange differential equations of the second kind has been derived. For the building presented as a rigid rod with the length equal to its height, also suspended on the supporting frame, the solution is performed using principles of dynamic calculations and methods of theoretical mechanics. It has been demonstrated, that the horizontal force in the suspension building is ten times less than the force in a traditional cantilever building, and that for the real horizontal stiffness of the supporting frame the dynamic strains are far from resonant values. The possibility of adjusting dynamic forces by regulating the stiffness of the supporting frame, length of the thread of suspension and other parameters. The proposed calculation schemes are useful for the preliminary calculations, and the finite design of the suspension building can be performed in modern software packages (e.g., Ansys, Abacus, etc.).
{"title":"Improved technique for the earthquake proof suspension building","authors":"T. Azizov, N. Jurkowska","doi":"10.21595/JME.2018.20411","DOIUrl":"https://doi.org/10.21595/JME.2018.20411","url":null,"abstract":"This paper presents the refined technique of dynamic calculations for suspension earthquake-resistant building. The improved design schemes of suspension buildings and structures have been demonstrated. Two versions of suspension buildings have been analysed. For the system with the building as a point mass suspension on the fixed bearing frame thread, a system of Lagrange differential equations of the second kind has been derived. For the building presented as a rigid rod with the length equal to its height, also suspended on the supporting frame, the solution is performed using principles of dynamic calculations and methods of theoretical mechanics. It has been demonstrated, that the horizontal force in the suspension building is ten times less than the force in a traditional cantilever building, and that for the real horizontal stiffness of the supporting frame the dynamic strains are far from resonant values. The possibility of adjusting dynamic forces by regulating the stiffness of the supporting frame, length of the thread of suspension and other parameters. The proposed calculation schemes are useful for the preliminary calculations, and the finite design of the suspension building can be performed in modern software packages (e.g., Ansys, Abacus, etc.).","PeriodicalId":42196,"journal":{"name":"Journal of Measurements in Engineering","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2018-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46193093","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}
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