Transport technologies最新文献

{"title":"Influence of wheel rotation resistance on oscillatory phenomena in steering drive of electric bus with electromechanical amplifier","authors":"B. Kindratskyy, R. Litvin","doi":"10.23939/tt2023.02.044","DOIUrl":"https://doi.org/10.23939/tt2023.02.044","url":null,"abstract":"Steering systems with an electromechanical amplifier (EMA) are a modern design solution compared to hydraulic and electro-hydraulic steering systems. Hydraulic steering amplifiers are used in the steering drives of modern trolleybuses and electric buses. If an electric motor powered from the power grid is used to drive the hydraulic pump in trolleybuses, then in electric buses, the source of electrical power is rechargeable batteries. Energy consumption to ensure the operation of the hydraulic power steering reduces the mileage of the electric bus between charging the batteries. Therefore, conducting research and substantiating the possibility of using EMA in electric buses is relevant and has important practical significance. Considering the design features of the electromechanical steering amplifier and the design of the steering axle of the Electron 19101 electric bus, a dynamic model of the drive for turning the controlled wheels of the electric bus was built on the spot. Based on the dynamic model of the drive for turning the controlled wheels of an electric bus with an electromechanical steering amplifier, a mathematical model of the drive and a stimulation model were developed in the MathLab Simulink environment for the study of oscillatory processes in the drive links when the wheels turn on a horizontal plane. The nature of the change of elastic torques in the links of the steering control drive of an electric bus with an electromechanical steering amplifier, the frequency of rotation of the rotor of the electric motor, the current strength in the windings of the rotor and stator of the electric motor, the angle of rotation of the steered wheels as a function of time was studied. It was found that the change in the moment of resistance to the rotation of the steered wheels increases smoothly, and the load on the drive links of the electromechanical power steering depends on the total gear ratio of the drive and its distribution between the gearbox and the steering rack. A decrease in the total transmission ratio of the drive leads to an increase in the speed of rotation of the driven wheels and an increase in elastic moments in the drive links. Transient processes in the electric part of the drive correspond to the characteristics of such electric motors in terms of the nature of the change and do not exceed the permissible values in terms of magnitude. It was established that the power characteristics of the electromechanical steering amplifier with the selected parameters and the electric motor can ensure the control of the wheels of the electric bus following the established requirements.","PeriodicalId":343801,"journal":{"name":"Transport technologies","volume":"17 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138970719","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}

{"title":"Characteristics of motorization's impact on the urban population","authors":"Y. Fornalchyk, V. Hilevych","doi":"10.23939/tt2023.02.068","DOIUrl":"https://doi.org/10.23939/tt2023.02.068","url":null,"abstract":"It is known that the most important thing in maintaining the good health of citizens is to save their lives from possible fatal road accidents, ensure the cleanliness of the air space, isolation from excessive noise pollution, electromagnetic fields. The listed negative impacts generate intensive traffic flows, which are the main component of transport systems. The task of identifying the patterns of changes in motorization over the past five years has become important. Motoriization, as it was previously believed, is one of the characteristics of the well-being of the population. Growth is already accompanied in large cities by negative phenomena, such as: road accidents with loss of life; deterioration of air pool quality; excessive traffic noise; excessive electromagnetic fields that cause intense traffic flows. All these negative characteristics of the increase in the level of motorization formed the subject of this study. First of all, on the basis of statistical data, a chronological pattern of growth in the indicator of motorization has been found by year were revealed based of statistical data (they are described by showing filamentous and rectilinear equations): there is a constant increase for the period from 2017 to 2022. Functional dependencies of the influence of motorization levels on each of the hazards were also found: the influence of motorization on fatal road accidents and air pollution is described by exponential equations, and noise and electromagnetic ones are described by straight-line non-decreasing equations. Based on the obtained results, conclusions were drawn regarding the reduction of their impact by replacing conventional transport systems with intelligent transport systems with elements of artificial intelligence.","PeriodicalId":343801,"journal":{"name":"Transport technologies","volume":"106 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138998540","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}

{"title":"An assessment of the effect of touting on Nigerian seaport operations: a case study of Apapa port","authors":"O. Nwaogbe, Caroline Onyinyechi Chieke, I. Nze","doi":"10.23939/tt2023.02.033","DOIUrl":"https://doi.org/10.23939/tt2023.02.033","url":null,"abstract":"In Nigeria, touting has been a challenge in the port, as it causes loss and diversion of cargo. Therefore, this study examined the effect of touting on the operational performance of the Apapa port. Specifically, a self-administered questionnaire was distributed to determine the extent of the touting on service delivery, security measures on operational quality dependability, pilfering on operations output safety, touting influencing elements on operational reliability, and touting activities on overall performance. Hypothesis one tested to what extent touts affect the service delivery of the Apapa port. The results showed that touts and their activities have effects on service delivery at Apapa port with multiple R values of 0.826, F value of 99 degrees of freedom of 50.860, a T value of 13.611 and a p-value of 0.001 calculated, which is less than 0.05 alpha value tabulated. Hypothesis two tested to what extent touting influencing elements affect the operational reliability of the Apapa port. The results show that touting impacting elements lower the performance reliability of the Apapa port with a multiple R of 0.861, an F value of 99 degrees of freedom of 68.161, a T value of 11.028 and a p-value calculated of 0.001, which is less than 0.05 alpha value. Hypothesis three tested to what extent touting activities affect the overall operational performance of the Apapa port. The results showed that touting influenced the overall performance of the Apapa port with a multiple R of 0.831, F value of 99 degrees of freedom of 53.030, a T value of 14.387 and a p-value of 0.001. It is less than an alpha value of 0.05. The results showed a relationship between touting and operational performance. It implies that the more touting activities there are, the greater the risk and possibility of loss of cargo. In addition, the results revealed a significant relationship between touting and service delivery, security measures and operational quality dependability, pilfering and operations output safety, touting influencing elements and operational reliability, and touting activities and overall performance. The study concludes that various security measures need to be in place to stop the activities of the touts. Therefore, the study suggests the eradication of touting, proper monitoring by security operatives of operational output such as cargoes, government provision of legal menial jobs for touts, and implementing a harsh policy against touts and touting activities.","PeriodicalId":343801,"journal":{"name":"Transport technologies","volume":"15 14","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139001258","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}

{"title":"Analysis of kinematic characteristics of a mobile caterpillar robot with a SCARA-type manipulator","authors":"V. Korendiy, O. Kachur, M. Boikiv, Yurii Novitskyi, Oleksandr Yaniv","doi":"10.23939/tt2023.02.056","DOIUrl":"https://doi.org/10.23939/tt2023.02.056","url":null,"abstract":"Automation and robotization of various production and technological processes in many industries is one of the leading trends in the development of modern society. Industrial robots have recently become quite widespread, and it is almost impossible to imagine any modern production in the fields of mechanical engineering (machine building), instrumentation, pharmaceuticals, food, chemical industries, etc., without robotic complexes. Over the past few decades, another area of robotics has emerged: autonomous mobile robots. It combines research in mechanics, electronics, and computer technologies, including artificial intelligence. Among the most common applications of autonomous mobile robots are the performance of various technological operations in places that are dangerous to human life (radiation, biological or chemical contamination) or uninhabitable (space, sea depths, volcanic craters, etc.). Mobile robots have also proven themselves in rescue operations during cataclysms and natural disasters, anti-terrorist operations, military operations, mine clearance, etc. Given the urgency of the issue of mobile robotics development, this article proposes a new design of an autonomous robotic complex built on the basis of a tracked chassis and equipped with a SCARA-type manipulator. The main task of the developed robot is to perform various technological operations in places where human presence is dangerous or impossible, in particular, when performing demining tasks. In the course of the research, the kinematics of the manipulator was analyzed in detail to determine its working area, and the kinematic parameters of the tracked chassis were experimentally tested while it was moving over rough terrain. The obtained results can be used to further improve the design and control system of the robot and manipulator and in the process of determining the specific technological tasks that will be assigned to this robotic platform.","PeriodicalId":343801,"journal":{"name":"Transport technologies","volume":"52 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138996378","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}

{"title":"Study of time indicators of public transport operation depending on the season of the year","authors":"M. Afonin, Rushikesh Amrutsamanvar","doi":"10.23939/tt2023.02.001","DOIUrl":"https://doi.org/10.23939/tt2023.02.001","url":null,"abstract":"Mobility problems in large cities of Ukraine and Eastern Europe are complicated by the fact that the increase of private transport volume significantly exceeds street and road network`s capacity. This is most noticeable during peak periods in terms of daylight hours and throughout the year. From the point of sustainable mobility view, this negative phenomenon significantly affects urban public transport, which does not have separate dedicated traffic lines. This article analyzes the issue regarding the deterioration of the transport situation in large cities. The reason for this is the increase in traffic on main streets during the day peaks, as well as the presence of seasonal traffic factors. If the issue of the occurrence and traffic jams duration and the increase in the correspondence time of private transport is sufficiently studied, then the problems of changing the schedules of public transport and taking into account the increase in the trip duration depending on the time of year need to be clarified. The routes of public transport, which do not have a separate infrastructure and move in the general flow together with private cars, were chosen for the study. According to the results of remote monitoring of public transport, a change in the trip duration and time lost due to the boarding and disembarking of passengers on similar trolleybus routes in different seasons was established. Based on the obtained data, a matrix of trip duration unevenness coefficients for public transport routes was formed, and a measure of the seasonality effect on these indicators was established. The obtained results make it possible to quantitatively determine the influence of the season and time of the day on the change in the trip duration, which can be applied in further studies using simulation tools and for practical use in drawing up seasonal traffic schedules. The results of the research complement the currently relevant scientific works, which concern the problems of seasonal mobility, as well as the influence of the social infrastructure objects functioning (schools, kindergartens, and other educational institutions) of cities on the peak load of the street and road network, which extends the duration of traffic not only for private but also public transport.","PeriodicalId":343801,"journal":{"name":"Transport technologies","volume":"73 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138999758","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}

{"title":"Assessment of the service quality in public transport (analysis of research in Lviv, Ukraine)","authors":"Mykola Zhuk, H.V. Pivtorak, I. Gits","doi":"10.23939/tt2023.02.012","DOIUrl":"https://doi.org/10.23939/tt2023.02.012","url":null,"abstract":"The paper assesses the quality of public transport services and the influence of individual components on the value of the overall satisfaction level with transport services. Public transport has many benefits in terms of energy savings, environmental impact, social equity and urban economy. The analysis of existing research confirms that the quality of service provided by the public transport system affects the intentions of potential passengers to use it more. However, the level of economic well-being, the state of development of the transport system, and the national strategy for developing social mobility influence the different perceptions of the importance of similar parameters of public transport functioning. The research was conducted based on the results of surveys of the population of Lviv. It was found that the perception of value indicators (fare and methods of paying for travel) differs the most depending on age, average monthly income and type of employment. The socio-economic indicators of the respondents have the least influence on the change in the estimation of time indicators of displacement. In this case, the level of satisfaction correlates with the actual durations of individual components of the movement (the time of the trip and the waiting time at the stop). According to the results of the surveys, the time parameters of the movement, the occupancy of the vehicle, the cleanliness of the vehicle, and the behavior of the driver have more influence on the overall assessment of the transport service quality indicator than the equipment of the stop, the convenience of boarding/alighting, the noise in the vehicle, and the convenience of paying for the fare. The obtained results can be useful for providers and customers of transport services when determining priority measures to improve the quality of public transport.","PeriodicalId":343801,"journal":{"name":"Transport technologies","volume":"22 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138996184","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}

{"title":"Impact of pedestrian flows on traffic delays before roundabouts","authors":"R. Bura, Roman Rohalskyy","doi":"10.23939/tt2023.02.023","DOIUrl":"https://doi.org/10.23939/tt2023.02.023","url":null,"abstract":"The paper examines a roundabout located in a residential district of Lviv city. The area has many attraction points, so traffic and pedestrian flow volumes are large. All approaches to the roundabout have unsignalized pedestrian crosswalks, three of which lack safety islands. Field studies were conducted on peak and off-peak periods, collecting primary indicators of traffic and pedestrian flows. Traffic flow delays were determined on the approaches to the roundabout under existing traffic conditions with the help of the PTV VISSIM software. Three options were proposed for arranging pedestrian crosswalks on approaches to the roundabout. The first option was an arrangement of safety islands on all pedestrian crosswalks. The second option was an arrangement of underground pedestrian crosswalks. The third option was the implementation of adapting traffic light control with a call button for pedestrians. Traffic simulation was carried out for all three proposed options with the finding of the delay per vehicle and the values of the average and maximum length of the queue of vehicles on the approaches to the roundabout. All three options showed better results of traffic delay than existing conditions. However, there were delays caused by the traffic flow itself. These delays are seen in the results of the simulation of option two. Traffic delays are the smallest at this option. Option one showed the highest values of traffic delays in comparison with the other two options. The advantages and disadvantages of each option for arranging pedestrian crosswalks are determined. Recommendations are given regarding the feasibility of locating various types of pedestrian crosswalks on the approaches to the roundabout. Given the research results, the best option from the view of traffic and pedestrian flows, their delays and safety is the third one.","PeriodicalId":343801,"journal":{"name":"Transport technologies","volume":"11 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138998432","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}

{"title":"The influence of important factors on the distribution of heat flows in elements of drum brakes of vehicles","authors":"H. Hudz, Mykhailo Hlobchak","doi":"10.23939/tt2023.01.083","DOIUrl":"https://doi.org/10.23939/tt2023.01.083","url":null,"abstract":"The movement of motor vehicles at high speeds is impossible without a braking system capable of ensuring high braking efficiency. It has been established that the most unstable link of the braking system is the brake mechanism, since from the energy point of view, braking with friction brakes is the process of converting part of the mechanical energy of the motor vehicle into heat. Braking is a long process during which many counterbody parameters change, in particular, thermophysical parameters due to temperature changes, friction coefficient, etc. If, under these circumstances, the surface and volume temperatures exceed the permissible values, then the frictional properties of the friction pairs and the conditions of the interaction of the parts change, which leads to a change in the characteristics of the brake mechanisms and the brake system as a whole. The standards of most countries and international prescriptions regulate braking performance meters not only for one-time emergency braking with cold brakes but also for emergency braking performed after the conversion of a given amount of energy into heat during a given time. It was found that the preservation of the necessary braking efficiency after the conversion of a given amount of energy into heat will be ensured only if the braking system has sufficient energy capacity. The object of the research is the distribution of heat flows in the elements of the brake mechanism, which determine the critical temperature of the friction surfaces. It was established that F. Charron's formula cannot correctly estimate such a distribution due to taking into account only the thermophysical properties of materials of friction pairs. It is shown that the influence of the design parameters of the brake and its modes of operation on the distribution of heat flows in the drum brake of a motor vehicle can also be estimated on grid thermal models with the involvement of the \"Fourier-2xyz\" software complex.","PeriodicalId":343801,"journal":{"name":"Transport technologies","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127162251","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}

{"title":"Impact of traffic volume and composition on the change in the speed of traffic flow","authors":"Oleh Hrytsun","doi":"10.23939/tt2023.01.012","DOIUrl":"https://doi.org/10.23939/tt2023.01.012","url":null,"abstract":"The problem of the change in the speed of traffic flow at different traffic volumes and compositions is researched in this study. The section of the road network with different geometric parameters (descent, ascent and horizontal section) was chosen for the study. The method of investigation of traffic flow`s speed and factors which have an impact on the reduction of road network capacity are analyzed. The change in the coefficients of the unevenness of traffic flow by hours of the day in the studied area was determined and a graph of the distribution of traffic volume by hours of the day was built. A diagram of the section was built to determine the speed of the traffic flow, on which the movement along the horizontal section, uphill and downhill movement is present. It was established that at a traffic volume of 700-800 p.c.u./h, the traffic flow moves at a constant speed (up to 10-15 km/h). Cumulative curves of traffic flow speed` distribution characterizing modes of traffic flow on the road network were built. It is determined that at volume-capacity ratio 0< z ≤ 0,4 on three investigated sections traffic flow moves with the speed from 35 km/h to 59 km/h. In the specialized software product PTV VISSIM, the simulation of the traffic flow on the horizontal section, ascent and descent has been developed. Using the MATHLAB software environment, it is shown how the speed of the traffic flow changes depending on the volume-capacity ratio and the share of the heterogeneous traffic flow. It was established that the highest speed of the flow is observed during the downhill movement – 58.62 km/h at the volume-capacity ratio – 0.13 and the share of heterogeneous traffic flow – 1.0 (100% cars). At a volume-capacity ratio of 0.88 and existing road conditions, the speed of traffic flow on the horizontal section and during uphill movement is almost the same (the average deviation is 6%). It can be explained by the fact that at a volume-capacity ratio of 0.88, traffic flow is in the traffic jam, hence, the speed of movement on the three sections is the same.","PeriodicalId":343801,"journal":{"name":"Transport technologies","volume":"133 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116362185","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}

{"title":"Mathematical modeling of the efficiency indicator of the functioning of the transport and production system in the conditions of the quarry of a metallurgical enterprise","authors":"B. Sereda, Darya Mykovska","doi":"10.23939/tt2023.01.048","DOIUrl":"https://doi.org/10.23939/tt2023.01.048","url":null,"abstract":"The study of the operation of quarry vehicles made it possible to form the target function of the study, taking into account the criterion of the efficiency of all processes of the system, which provides for the reduction of costs for the operation of the transport and production system of the quarry of a metallurgical enterprise, namely, the subsystems: “Incoming raw materials”, “Processing of raw materials”, “Sales of raw materials”. Factors influencing the cost indicator are highlighted. These factors include the production downtime of motor vehicles, the speed of motor vehicles with cargo, and the speed of motor vehicles without cargo. The values of these factors were obtained in result of timing the operation of motor vehicles on technological routes for four days. The levels of variation intervals and the nature of their changes for the three regimes were calculated for each of the subsystems. A regression analysis of the investigated factors was carried out to model the costs. The response surfaces of the obtained mathematical models are constructed, namely: the influence of the production downtime of motor vehicles and the speed of movement without cargo on the costs of functioning of subsystems, the influence of production downtime of motor vehicles and the speed of movement with cargo on the costs of the functioning of subsystems, the influence of the speed of movement with cargo and speed of movement without cargo for the costs of functioning of subsystems. The optimal values for reducing the cost of functioning of the “Processing of raw materials” subsystem are the value of production downtime – 4-5 min., the speed of motor vehicles without cargo – 9 min., and the speed of motor vehicles with cargo – 9 km/h. The optimal values for reducing the cost of functioning of the “Sales of raw materials” subsystem are the value of production downtime – 4-6 min., the speed of motor vehicles without cargo – 14-16 min., and the speed of motor vehicles with cargo – 13-15 km/h. The optimal values for reducing the cost of functioning of the subsystem “Incoming raw materials” are: the value of production downtime is 4-5 minutes, the speed of motor vehicles without cargo is 7-8 km/h, the speed of motor vehicles with cargo is 10 km/h.","PeriodicalId":343801,"journal":{"name":"Transport technologies","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128170949","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}