{"title":"Mitigation of Debris Flows—Research and Practice in Hong Kong","authors":"K. Ho, R. Koo, J. Kwan","doi":"10.2113/EEG-D-20-00009","DOIUrl":"https://doi.org/10.2113/EEG-D-20-00009","url":null,"abstract":"","PeriodicalId":50518,"journal":{"name":"Environmental & Engineering Geoscience","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76427898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Leonardi, M. Pirulli, M. Barbero, F. Barpi, M. Borri-Brunetto, O. Pallara, C. Scavia, V. Segor
Debris flows are one of the most complex and devastating natural phenomena, and they affect mountainous areas throughout the world. Structural measures are currently adopted to mitigate the related hazard in urbanized areas. However, their design requires an estimate of the impact force, which is an open issue. The numerous formulae proposed in the literature require the assignment of empirical coefficients and an evaluation of the kinematic characteristics of the incoming flow. Both are generally not known a priori. In this article, we present the Grand Valey torrent site (Italian Alps). A monitoring system made up of strain gauges was installed on a filter barrier at the site, allowing the evaluation of impact forces. The system provides pivotal information for calibrating impact formulae. Two debris flows occurred during the monitoring period. We present the interpretation of videos, impact measurements, and the results of numerical analyses. The combined analysis allows a back calculation of the events in terms of forces, flow depth, and velocity. Thus, we investigate the applicability of the impact formulae suggested in the literature and of the recommended empirical coefficients. The results highlight that hydrostatic effects dominated the impact during the first event, while hydrodynamic effects prevailed in the second one.
{"title":"Impact of Debris Flows on Filter Barriers: Analysis Based on Site Monitoring Data","authors":"A. Leonardi, M. Pirulli, M. Barbero, F. Barpi, M. Borri-Brunetto, O. Pallara, C. Scavia, V. Segor","doi":"10.2113/EEG-D-20-00013","DOIUrl":"https://doi.org/10.2113/EEG-D-20-00013","url":null,"abstract":"\u0000 Debris flows are one of the most complex and devastating natural phenomena, and they affect mountainous areas throughout the world. Structural measures are currently adopted to mitigate the related hazard in urbanized areas. However, their design requires an estimate of the impact force, which is an open issue. The numerous formulae proposed in the literature require the assignment of empirical coefficients and an evaluation of the kinematic characteristics of the incoming flow. Both are generally not known a priori. In this article, we present the Grand Valey torrent site (Italian Alps). A monitoring system made up of strain gauges was installed on a filter barrier at the site, allowing the evaluation of impact forces. The system provides pivotal information for calibrating impact formulae. Two debris flows occurred during the monitoring period. We present the interpretation of videos, impact measurements, and the results of numerical analyses. The combined analysis allows a back calculation of the events in terms of forces, flow depth, and velocity. Thus, we investigate the applicability of the impact formulae suggested in the literature and of the recommended empirical coefficients. The results highlight that hydrostatic effects dominated the impact during the first event, while hydrodynamic effects prevailed in the second one.","PeriodicalId":50518,"journal":{"name":"Environmental & Engineering Geoscience","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2021-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79350891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Laboratory experiments on granular flows remain essential tools for gaining insight into several aspects of granular dynamics that are inaccessible from field-scale investigations. Here, we report an experimental campaign on steady dry granular flows in a flume with inclination of 35°. Different flow rates are investigated by adjusting an inflow gate, while various kinematic boundary conditions are observed by varying the basal roughness. The flume is instrumented with high-speed cameras and a no-flicker LED lamp to get reliable particle image velocimetry measurements in terms of both time averages and second-order statistics (i.e., granular temperature). The same measuring instruments are also used to obtain concurrent estimations of the solid volume fraction at the sidewall by employing the stochastic-optical method (SOM). This innovative approach uses a measurable quantity, called two-dimensional volume fraction, which is correlated with the near-wall volume fraction and is obtainable from digital images under controlled illumination conditions. The knowledge of this quantity allows the indirect measurement of the near-wall volume fraction thanks to a stochastic transfer function previously obtained from numerical simulations of distributions of randomly dispersed spheres. The combined measurements of velocity and volume fraction allow a better understanding of the flow dynamics and reveal the superposition of different flow regimes along the flow depth, where frictional and collisional mechanisms exhibit varying relative magnitudes.
{"title":"Velocity and Volume Fraction Measurements of Granular Flows in a Steep Flume","authors":"L. Sarno, M. Papa, L. Carleo, P. Villani","doi":"10.2113/EEG-D-20-00027","DOIUrl":"https://doi.org/10.2113/EEG-D-20-00027","url":null,"abstract":"\u0000 Laboratory experiments on granular flows remain essential tools for gaining insight into several aspects of granular dynamics that are inaccessible from field-scale investigations. Here, we report an experimental campaign on steady dry granular flows in a flume with inclination of 35°. Different flow rates are investigated by adjusting an inflow gate, while various kinematic boundary conditions are observed by varying the basal roughness. The flume is instrumented with high-speed cameras and a no-flicker LED lamp to get reliable particle image velocimetry measurements in terms of both time averages and second-order statistics (i.e., granular temperature). The same measuring instruments are also used to obtain concurrent estimations of the solid volume fraction at the sidewall by employing the stochastic-optical method (SOM). This innovative approach uses a measurable quantity, called two-dimensional volume fraction, which is correlated with the near-wall volume fraction and is obtainable from digital images under controlled illumination conditions. The knowledge of this quantity allows the indirect measurement of the near-wall volume fraction thanks to a stochastic transfer function previously obtained from numerical simulations of distributions of randomly dispersed spheres. The combined measurements of velocity and volume fraction allow a better understanding of the flow dynamics and reveal the superposition of different flow regimes along the flow depth, where frictional and collisional mechanisms exhibit varying relative magnitudes.","PeriodicalId":50518,"journal":{"name":"Environmental & Engineering Geoscience","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2021-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86814506","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lee Li Yong, V. Anggraini, M. Raghunandan, M. Taha
This study assessed the performance of residual soils with regard to their macrostructural and microstructural properties and compatibility with leachate in pursuit of exploring alternative cost-effective and efficient landfill liner materials. A series of laboratory investigations was conducted on three residual soil samples by using tap water and leachate as permeation fluid to achieve the objectives of the study. The zeta potential measurements revealed that the presence of multivalent cations in the leachate decreased the diffuse double layer (DDL) thickness around the soil particles. The reduced DDL thickness caused a decrease in Atterberg limits of soil-leachate samples and changes in the classification of fine fractions. Additionally, the effects of pore clogging attributed to chemical precipitation and bioclogging were responsible for the reduction in measured hydraulic conductivities of soil-leachate samples. These effects can be clearly observed from the field-emission scanning electron microscopy images of soil-leachate samples with the appearance of less visible voids that led to a more compact and dense structure. The formation of new non-clay minerals and associated changes in the Al and Si ratio as reflected in the x-ray diffraction diffractograms and energy-dispersive x-ray analyses, respectively, were attributed to the effects of chemical precipitation. This study concluded that S1 and S2 residual soil samples are potential landfill liner materials because they possess adequate grading characteristics, adequate unconfined compressive strength, low hydraulic conductivity, and good compatibility with leachate. In contrast, the S3 sample requires further treatment to enhance its properties in order to comply with the requirements of landfill liner materials.
{"title":"Macrostructural and Microstructural Properties of Residual Soils as Engineered Landfill Liner Materials","authors":"Lee Li Yong, V. Anggraini, M. Raghunandan, M. Taha","doi":"10.2113/EEG-D-20-00004","DOIUrl":"https://doi.org/10.2113/EEG-D-20-00004","url":null,"abstract":"\u0000 This study assessed the performance of residual soils with regard to their macrostructural and microstructural properties and compatibility with leachate in pursuit of exploring alternative cost-effective and efficient landfill liner materials. A series of laboratory investigations was conducted on three residual soil samples by using tap water and leachate as permeation fluid to achieve the objectives of the study. The zeta potential measurements revealed that the presence of multivalent cations in the leachate decreased the diffuse double layer (DDL) thickness around the soil particles. The reduced DDL thickness caused a decrease in Atterberg limits of soil-leachate samples and changes in the classification of fine fractions. Additionally, the effects of pore clogging attributed to chemical precipitation and bioclogging were responsible for the reduction in measured hydraulic conductivities of soil-leachate samples. These effects can be clearly observed from the field-emission scanning electron microscopy images of soil-leachate samples with the appearance of less visible voids that led to a more compact and dense structure. The formation of new non-clay minerals and associated changes in the Al and Si ratio as reflected in the x-ray diffraction diffractograms and energy-dispersive x-ray analyses, respectively, were attributed to the effects of chemical precipitation. This study concluded that S1 and S2 residual soil samples are potential landfill liner materials because they possess adequate grading characteristics, adequate unconfined compressive strength, low hydraulic conductivity, and good compatibility with leachate. In contrast, the S3 sample requires further treatment to enhance its properties in order to comply with the requirements of landfill liner materials.","PeriodicalId":50518,"journal":{"name":"Environmental & Engineering Geoscience","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2021-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80103386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Regional-scale assessments for debris-flow and debris-flood propagation and avulsion on fans can be challenging. Geomorphological mapping based on aerial or satellite imagery requires substantial field verification effort. Surface evidence of past events may be obfuscated by development or obscured by repeat erosion or debris inundation, and trenching may be required to record the sedimentary architecture and date past events. This paper evaluates a methodology for debris-flow and debris-flood susceptibility mapping at regional scale based on a combination of digital elevation model (DEM) metrics to identify potential debris source zones and flow propagation modeling using the Flow-R code that is calibrated through comparison to mapped alluvial fans. The DEM metrics enable semi-automated identification and preliminary, process-based classification of streams prone to debris flow and debris flood. Flow-R is a susceptibility mapping tool that models potential flow inundation based on a combination of spreading and runout algorithms considering DEM topography and empirical propagation parameters. The methodology is first evaluated at locations where debris-flow and debris-flood hazards have been previously assessed based on field mapping and detailed numerical modeling. It is then applied over a 125,000 km2 area in southern British Columbia, Canada. The motivation for the application of this methodology is that it represents an objective and repeatable approach to susceptibility mapping, which can be integrated in a debris-flow and debris-flood risk prioritization framework at regional scale to support risk management decisions.
{"title":"Debris-Flow and Debris-Flood Susceptibility Mapping for Geohazard Risk Prioritization","authors":"M. Sturzenegger, Kris Holm, C. Lau, M. Jakob","doi":"10.2113/EEG-D-20-00006","DOIUrl":"https://doi.org/10.2113/EEG-D-20-00006","url":null,"abstract":"\u0000 Regional-scale assessments for debris-flow and debris-flood propagation and avulsion on fans can be challenging. Geomorphological mapping based on aerial or satellite imagery requires substantial field verification effort. Surface evidence of past events may be obfuscated by development or obscured by repeat erosion or debris inundation, and trenching may be required to record the sedimentary architecture and date past events. This paper evaluates a methodology for debris-flow and debris-flood susceptibility mapping at regional scale based on a combination of digital elevation model (DEM) metrics to identify potential debris source zones and flow propagation modeling using the Flow-R code that is calibrated through comparison to mapped alluvial fans. The DEM metrics enable semi-automated identification and preliminary, process-based classification of streams prone to debris flow and debris flood. Flow-R is a susceptibility mapping tool that models potential flow inundation based on a combination of spreading and runout algorithms considering DEM topography and empirical propagation parameters. The methodology is first evaluated at locations where debris-flow and debris-flood hazards have been previously assessed based on field mapping and detailed numerical modeling. It is then applied over a 125,000 km2 area in southern British Columbia, Canada. The motivation for the application of this methodology is that it represents an objective and repeatable approach to susceptibility mapping, which can be integrated in a debris-flow and debris-flood risk prioritization framework at regional scale to support risk management decisions.","PeriodicalId":50518,"journal":{"name":"Environmental & Engineering Geoscience","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2021-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80460680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sinkholes are common surface manifestations of the presence of networks of subsurface caverns in areas where the bedrock geology is dominated by soluble rocks such as limestones. Accurate mapping of sinkholes is crucial as they are hazardous to transportation infrastructure and may serve as conduits of contaminants to the groundwater. The use of high-resolution digital elevation models extracted from LiDAR and tools in ArcGIS have made it a simple task to automate the process of identification of closed depressions. However, these automated methods do not differentiate between sinkholes and other man-made depressions. Multivariate statistical methods such as linear discriminant analysis, quadratic discriminant analysis, and logistic regression were used to produce predictive models based on selected shape factor values such as circularity, sphericity, and curvature. Curvature values, especially when combined with circularity, were found to be the most powerful variables in separating closed depressions into sinkholes and other artificial depressions.
{"title":"Improved Automated Mapping of Sinkholes Using High-Resolution DEMs","authors":"Yonathan Admassu, Celestine Woodruff","doi":"10.2113/EEG-D-20-00081","DOIUrl":"https://doi.org/10.2113/EEG-D-20-00081","url":null,"abstract":"\u0000 Sinkholes are common surface manifestations of the presence of networks of subsurface caverns in areas where the bedrock geology is dominated by soluble rocks such as limestones. Accurate mapping of sinkholes is crucial as they are hazardous to transportation infrastructure and may serve as conduits of contaminants to the groundwater. The use of high-resolution digital elevation models extracted from LiDAR and tools in ArcGIS have made it a simple task to automate the process of identification of closed depressions. However, these automated methods do not differentiate between sinkholes and other man-made depressions. Multivariate statistical methods such as linear discriminant analysis, quadratic discriminant analysis, and logistic regression were used to produce predictive models based on selected shape factor values such as circularity, sphericity, and curvature. Curvature values, especially when combined with circularity, were found to be the most powerful variables in separating closed depressions into sinkholes and other artificial depressions.","PeriodicalId":50518,"journal":{"name":"Environmental & Engineering Geoscience","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2021-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73912909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Debris-flow events often comprise a sequence of surges, sometimes termed “roll waves.” The reason for this surging behavior is still a matter of debate. Explanations include the growth of hydraulic instabilities, periodic sediment deposition and release, or grain size sorting. High-resolution field measurements together with triggering rainfall characteristics are rare. We present results for 3 years of monitoring debris-flow events at Lattenbach Creek in the western part of Austria. The monitoring system includes a weather station in the headwaters of the creek, radar sensors for measuring flow depth at different locations along the channel, as well as a two-dimensional rotational laser sensor installed over a fixed cross section that yields a three-dimensional surface model of the passing debris-flow event. We find that the debris flows at Lattenbach Creek were all triggered by rainstorms of less than 2 hours and exhibited surges for each observed event. The velocities of the surges were up to twice as high as the front velocity. Often, the first surges that included boulders and woody debris had the highest flow depth and discharge and showed an irregular geometry. The shape of the surges in the second half of the flow, which carried smaller grain sizes and less woody debris, were rather regular and showed a striking geometric similarity, but still high velocities. The results of our monitoring efforts aim to improve our understanding of the surging behavior of debris flows and provide data for model testing for the scientific community.
{"title":"Monitoring Debris-Flow Surges and Triggering Rainfall at the Lattenbach Creek, Austria","authors":"J. Huebl, R. Kaitna","doi":"10.2113/EEG-D-20-00010","DOIUrl":"https://doi.org/10.2113/EEG-D-20-00010","url":null,"abstract":"\u0000 Debris-flow events often comprise a sequence of surges, sometimes termed “roll waves.” The reason for this surging behavior is still a matter of debate. Explanations include the growth of hydraulic instabilities, periodic sediment deposition and release, or grain size sorting. High-resolution field measurements together with triggering rainfall characteristics are rare. We present results for 3 years of monitoring debris-flow events at Lattenbach Creek in the western part of Austria. The monitoring system includes a weather station in the headwaters of the creek, radar sensors for measuring flow depth at different locations along the channel, as well as a two-dimensional rotational laser sensor installed over a fixed cross section that yields a three-dimensional surface model of the passing debris-flow event. We find that the debris flows at Lattenbach Creek were all triggered by rainstorms of less than 2 hours and exhibited surges for each observed event. The velocities of the surges were up to twice as high as the front velocity. Often, the first surges that included boulders and woody debris had the highest flow depth and discharge and showed an irregular geometry. The shape of the surges in the second half of the flow, which carried smaller grain sizes and less woody debris, were rather regular and showed a striking geometric similarity, but still high velocities. The results of our monitoring efforts aim to improve our understanding of the surging behavior of debris flows and provide data for model testing for the scientific community.","PeriodicalId":50518,"journal":{"name":"Environmental & Engineering Geoscience","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2021-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85545690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The internal deformation behavior of natural debris flows is of interest for model development and model testing for debris-flow hazard mitigation. Up to now, only a view attempts were made to measure velocity profiles in natural debris flows due to low predictability and high destructive power of these flows. In this contribution we present recent advances of measuring in-situ velocity profiles together with flow parameters like flow depth, basal normal stress, and pore fluid pressure. For that a fin-shaped monitoring barrier was constructed in the Gadria creek (IT), laterally carrying an array of paired conductivity sensors. We present results from two debris-flow events with volumes of around 5,000 m3 each. Compared to the first event on July 10th, 2017, the second event on August 19th, 2017, was visually more liquid. Both debris flows exhibited significant longitudinal changes of flow properties like flow depth and density. The liquefaction ratios reached values up to unity in some sections of the flows. Velocity profiles for the July event were mostly concave up, while the profiles for the more liquid event in August were linear to convex. Though limited by boundary roughness at the wall and occasional sediment deposition on the force plates and pressure sensors, these measurements gain new insights of the dynamics of real-scale debris flows.
{"title":"Measurements of Velocity Profiles in Natural Debris Flows: A View behind the Muddy Curtain","authors":"G. Nagl, J. Hübl, R. Kaitna","doi":"10.2113/EEG-D-20-00115","DOIUrl":"https://doi.org/10.2113/EEG-D-20-00115","url":null,"abstract":"The internal deformation behavior of natural debris flows is of interest for model development and model testing for debris-flow hazard mitigation. Up to now, only a view attempts were made to measure velocity profiles in natural debris flows due to low predictability and high destructive power of these flows. In this contribution we present recent advances of measuring in-situ velocity profiles together with flow parameters like flow depth, basal normal stress, and pore fluid pressure. For that a fin-shaped monitoring barrier was constructed in the Gadria creek (IT), laterally carrying an array of paired conductivity sensors. We present results from two debris-flow events with volumes of around 5,000 m3 each. Compared to the first event on July 10th, 2017, the second event on August 19th, 2017, was visually more liquid. Both debris flows exhibited significant longitudinal changes of flow properties like flow depth and density. The liquefaction ratios reached values up to unity in some sections of the flows. Velocity profiles for the July event were mostly concave up, while the profiles for the more liquid event in August were linear to convex. Though limited by boundary roughness at the wall and occasional sediment deposition on the force plates and pressure sensors, these measurements gain new insights of the dynamics of real-scale debris flows.","PeriodicalId":50518,"journal":{"name":"Environmental & Engineering Geoscience","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81909240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-02-01DOI: 10.2113/GSEEGEOSCI.27.1.1
P. Santi, L. Schaefer
{"title":"Introduction to Special Issue on Debris Flows Volume 1","authors":"P. Santi, L. Schaefer","doi":"10.2113/GSEEGEOSCI.27.1.1","DOIUrl":"https://doi.org/10.2113/GSEEGEOSCI.27.1.1","url":null,"abstract":"","PeriodicalId":50518,"journal":{"name":"Environmental & Engineering Geoscience","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76513549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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