Proc. Meet. Acoust.最新文献

{"title":"Different origins of acoustic streaming at resonance","authors":"Jacob Bach, H. Bruus","doi":"10.1121/2.0000927","DOIUrl":"https://doi.org/10.1121/2.0000927","url":null,"abstract":"Acoustic streaming is a nonlinear phenomenon that plays an essential role in microscale acoustofluidic devices for handling of sub-micrometer particles. However, the streaming patterns observed in experiments can be of complicated and non-intuitive character, and therefore, experiments, and device optimization are often carried out in a trial-and-error manner. To overcome this obstacle, we classify acoustic streaming based on our recently developed theory of acoustic streaming. Using this theory we have shown that acoustic streaming is driven partly by Reynolds stresses in the bulk and partly by a slip-velocity condition at the walls due to Reynolds stresses in the acoustic boundary layers. Hence, in our classification, we distinguish between boundary-layer-driven and bulk-driven streaming. For boundary-layer-driven streaming at resonance, we classify the two physically relevant limits of parallel and perpendicular acoustics as well as the intermediate range. For bulk-driven streaming we find that the acoustic intensity vector plays a central role, and that this quantity can give rise to a strong bulk-driven streaming, if the acoustic fields have large angular momentum. In this context, we analyze mechanisms that can lead to rotating resonant modes in acoustic microchannels.Acoustic streaming is a nonlinear phenomenon that plays an essential role in microscale acoustofluidic devices for handling of sub-micrometer particles. However, the streaming patterns observed in experiments can be of complicated and non-intuitive character, and therefore, experiments, and device optimization are often carried out in a trial-and-error manner. To overcome this obstacle, we classify acoustic streaming based on our recently developed theory of acoustic streaming. Using this theory we have shown that acoustic streaming is driven partly by Reynolds stresses in the bulk and partly by a slip-velocity condition at the walls due to Reynolds stresses in the acoustic boundary layers. Hence, in our classification, we distinguish between boundary-layer-driven and bulk-driven streaming. For boundary-layer-driven streaming at resonance, we classify the two physically relevant limits of parallel and perpendicular acoustics as well as the intermediate range. For bulk-driven streaming we find that the aco...","PeriodicalId":20469,"journal":{"name":"Proc. Meet. Acoust.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85912193","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":"Clinical studies of biceps anisotropy, relaxation and nonlinearity with a medical device for ultrasonic imaging","authors":"T. Krit, Mariya Begicheva, Y. Kamalov, V. Andreev","doi":"10.1121/2.0000923","DOIUrl":"https://doi.org/10.1121/2.0000923","url":null,"abstract":"We applied a commercial ultrasonic clinical diagnostic system for studies of human biceps. The investigated area was visualized in B-mode at a frequency of 8 MHz. We selected 1 cm and 2.5 cm depths for shear wave excitation. On these depths, the focused ultrasonic wave caused the acoustical radiation force. Due to nonlinear mechanism of excitation, a shear wave arose. The results we have obtained show that the biceps have the shear moduli of the order of 10 kPa. The loaded biceps demonstrated the nonlinear behavior better pronounced for the volunteer with smaller body mass index (BMI). As the load on the biceps increases, the shear modulus measured along the muscle fibers grows. The observed growth was stronger for the shear modulus of the short head. The shear modulus, measured in the direction across the fibers of the biceps, does not depend on the magnitude of the applied load and remains at the unloaded value. In 1 minute after load is removed the biceps tend to relax and its shear moduli turn their initial values.We applied a commercial ultrasonic clinical diagnostic system for studies of human biceps. The investigated area was visualized in B-mode at a frequency of 8 MHz. We selected 1 cm and 2.5 cm depths for shear wave excitation. On these depths, the focused ultrasonic wave caused the acoustical radiation force. Due to nonlinear mechanism of excitation, a shear wave arose. The results we have obtained show that the biceps have the shear moduli of the order of 10 kPa. The loaded biceps demonstrated the nonlinear behavior better pronounced for the volunteer with smaller body mass index (BMI). As the load on the biceps increases, the shear modulus measured along the muscle fibers grows. The observed growth was stronger for the shear modulus of the short head. The shear modulus, measured in the direction across the fibers of the biceps, does not depend on the magnitude of the applied load and remains at the unloaded value. In 1 minute after load is removed the biceps tend to relax and its shear moduli turn their i...","PeriodicalId":20469,"journal":{"name":"Proc. Meet. Acoust.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83520127","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":"Prospective medical applications of Nonlinear Time Reversal Acoustics","authors":"A. Sutin, H. Salloum","doi":"10.1121/2.0000920","DOIUrl":"https://doi.org/10.1121/2.0000920","url":null,"abstract":"Time Reversal Acoustic (TRA) focusing methods provide precise focusing and acoustic energy to chosen areas of the body, where various medical applications of these methods are under investigation. Here, we consider three prospective applications of the Nonlinear effects in TRA. Preliminary experiments for two of them were conducted several years ago, but were not published. A new third method combines TRA focusing with nonlinear acoustic imaging of ultrasonic contrast agents (UCA) for the following applications: 1. Nonlinear TRA method for blood pressure measurements directly in the blood stream. This method is based on the measurement of the second harmonic signal from an Ultrasonic Contrast Agent injected in the blood. 2. Nonlinear TRA for osteoporosis assessment. This is based on the concentration of acoustic energy of two signals with different frequencies in a small volume of bone. Measurements are made with a signal that sums the frequencies. Tests were conducted with a human calcanei bone sample. 3. Nonlinear TRA focusing to UCA for precise treatment of target areas and enhancement drug and gene delivery. This method is based on the reception of signals of nonlinear scattering from UCA and their frequency transformation and application of transferred signals for TRA focusing. Time Reversal Acoustic (TRA) focusing methods provide precise focusing and acoustic energy to chosen areas of the body, where various medical applications of these methods are under investigation. Here, we consider three prospective applications of the Nonlinear effects in TRA. Preliminary experiments for two of them were conducted several years ago, but were not published. A new third method combines TRA focusing with nonlinear acoustic imaging of ultrasonic contrast agents (UCA) for the following applications: 1. Nonlinear TRA method for blood pressure measurements directly in the blood stream. This method is based on the measurement of the second harmonic signal from an Ultrasonic Contrast Agent injected in the blood. 2. Nonlinear TRA for osteoporosis assessment. This is based on the concentration of acoustic energy of two signals with different frequencies in a small volume of bone. Measurements are made with a signal that sums the frequencies. Tests were conducted with a human calcanei bone sample. ...","PeriodicalId":20469,"journal":{"name":"Proc. Meet. Acoust.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87796183","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":"Nonlinear relaxation in geomaterials: New results","authors":"L. Ostrovsky, A. Lebedev, S. Manakov, Jérémy Rivière, P. Shokouhi, R. Guyer, M. S. Geesey, P. Johnson","doi":"10.1121/2.0000910","DOIUrl":"https://doi.org/10.1121/2.0000910","url":null,"abstract":"Numerous acoustic experiments demonstrate that in media with a complex structure, such as rock, the elastic response is characterized by (i) a decrease in the material modulus during wave excitation, typically with a hysteresis (fast nonlinear dynamics), and (ii) long-time recovery to the original equilibrium modulus (slow dynamics). Here, a physical model of a granular material with an inter-grain contact potential having one or more metastable wells suggested earlier is significantly developed to include a non-logarithmic stage and the joint action of excitation and recovery. Theoretical results are compared with our experimental data.Numerous acoustic experiments demonstrate that in media with a complex structure, such as rock, the elastic response is characterized by (i) a decrease in the material modulus during wave excitation, typically with a hysteresis (fast nonlinear dynamics), and (ii) long-time recovery to the original equilibrium modulus (slow dynamics). Here, a physical model of a granular material with an inter-grain contact potential having one or more metastable wells suggested earlier is significantly developed to include a non-logarithmic stage and the joint action of excitation and recovery. Theoretical results are compared with our experimental data.","PeriodicalId":20469,"journal":{"name":"Proc. Meet. Acoust.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88514038","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":"Numerical investigation of self-focused Lamb waves in anisotropic media","authors":"J. Spytek, L. Pieczonka, P. Kijanka, L. Ambrozinski","doi":"10.1121/2.0000912","DOIUrl":"https://doi.org/10.1121/2.0000912","url":null,"abstract":"Ultrasonic arrays are widely used in various fields including non-destructive testing and structural health monitoring (SHM) areas. Their application for inspection of anisotropic plates using guided waves is challenging, due to insufficient knowledge of angle-dependent wave velocity in the medium. Since time-reversal permits waves self-focusing without the knowledge about precise wave speed values, it seems to be a feasible solution for waves-steering in anisotropic media. In this paper performance of decomposition of the time-reversal operator (DORT) algorithm as well as its extended DORT-CWT method were studied on data from numerical simulations. The propagation of the guided ultrasonic waves in an anisotropic carbon fiber reinforced polymer (CFRP) plate was modelled using the local interaction simulation approach. Several application scenarios were investigated including different number and placement of the damage locations. In each case a number of simulations were performed to obtain the inter-element impulse responses for all the assumed transducers. The responses were decomposed to find the phase shifts and amplitudes necessary to focus on the scatterers. Accuracy of the estimated parameters for the DORT and DORT-CWT methods was verified by performing the backpropagation using all emitters in phased array mode. The presented approach produced accurate focusing on particular damage locations.Ultrasonic arrays are widely used in various fields including non-destructive testing and structural health monitoring (SHM) areas. Their application for inspection of anisotropic plates using guided waves is challenging, due to insufficient knowledge of angle-dependent wave velocity in the medium. Since time-reversal permits waves self-focusing without the knowledge about precise wave speed values, it seems to be a feasible solution for waves-steering in anisotropic media. In this paper performance of decomposition of the time-reversal operator (DORT) algorithm as well as its extended DORT-CWT method were studied on data from numerical simulations. The propagation of the guided ultrasonic waves in an anisotropic carbon fiber reinforced polymer (CFRP) plate was modelled using the local interaction simulation approach. Several application scenarios were investigated including different number and placement of the damage locations. In each case a number of simulations were performed to obtain the inter-elem...","PeriodicalId":20469,"journal":{"name":"Proc. Meet. Acoust.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89652208","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":"Experimental considerations of droplet manipulation mechanism using surface acoustic wave devices","authors":"J. Kondoh, Tomohiko Fukaya","doi":"10.1121/2.0000904","DOIUrl":"https://doi.org/10.1121/2.0000904","url":null,"abstract":"Droplet manipulation is one of the important application of the SAW device. When a droplet is placed on a SAW device, the longitudinal wave radiates into the droplet. Nonlinear acoustic phenomena are caused by the radiated longitudinal wave from the SAW. Droplet manipulation is one of those phenomena. It is important to investigate the minimum radiation force to manipulate the droplet by the SAW. In this paper, the radiation force in a droplet is experimentally measured. The radiation force was measured by varying an applied electrical power, water volume, and concentration of glycerol-water mixture. The minimum radiation force for manipulating 10 micro little was 0.168 mN. Also, the water droplet manipulated was observed by a high speed camera. When the longitudinal wave radiates into the droplet and the radiation force is larger than the surface tension of the water, the tip of the droplet is extended in the SAW propagation direction. In other words, the radiation force is acting only tip of the droplet. The extended length depends on the applied power and the duty factor. Other parts of the droplet act as binding force. The force only acts the tip of the droplet and the end part is dragged.Droplet manipulation is one of the important application of the SAW device. When a droplet is placed on a SAW device, the longitudinal wave radiates into the droplet. Nonlinear acoustic phenomena are caused by the radiated longitudinal wave from the SAW. Droplet manipulation is one of those phenomena. It is important to investigate the minimum radiation force to manipulate the droplet by the SAW. In this paper, the radiation force in a droplet is experimentally measured. The radiation force was measured by varying an applied electrical power, water volume, and concentration of glycerol-water mixture. The minimum radiation force for manipulating 10 micro little was 0.168 mN. Also, the water droplet manipulated was observed by a high speed camera. When the longitudinal wave radiates into the droplet and the radiation force is larger than the surface tension of the water, the tip of the droplet is extended in the SAW propagation direction. In other words, the radiation force is acting only tip of the droplet...","PeriodicalId":20469,"journal":{"name":"Proc. Meet. Acoust.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73328769","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":"Numerical study on growth and collapse of cloud cavitation in a focused ultrasound field","authors":"K. Okita","doi":"10.1121/2.0000907","DOIUrl":"https://doi.org/10.1121/2.0000907","url":null,"abstract":"Acoustic cavitation is becoming increasingly important in therapeutic ultrasound applications. Nonlinear behavior as well as spatial distribution of cloud cavitation in a focused ultrasound field needs to be clarified to enhance the mechanical effects of cavitation on treatments such as lithotripsy and histotripsy. For this purpose, an ultrasound simulator treating cavitation has been developing. Since the distribution of the cloud cavitation generated in a focused ultrasound field results from the complex interactions between bubble oscillation and ultrasound, the bubble oscillation is strongly coupled with the focused ultrasound field. In addition, rectified diffusion, which plays an important role in the cavitation bubble growth, is taken into account. A focused ultrasound lithotripsy using the collapse of cloud cavitation was demonstrated numerically. The cloud cavitation is generated by the high frequency ultrasound waves and is collapsed by the low frequency ultrasound waves. As the result of the simulation, the cavitation bubble growth from nuclei around focus region in front of the model stone were reproduced. Then, the collapse of the cloud cavitation caused high pressure on the surface of the stone.Acoustic cavitation is becoming increasingly important in therapeutic ultrasound applications. Nonlinear behavior as well as spatial distribution of cloud cavitation in a focused ultrasound field needs to be clarified to enhance the mechanical effects of cavitation on treatments such as lithotripsy and histotripsy. For this purpose, an ultrasound simulator treating cavitation has been developing. Since the distribution of the cloud cavitation generated in a focused ultrasound field results from the complex interactions between bubble oscillation and ultrasound, the bubble oscillation is strongly coupled with the focused ultrasound field. In addition, rectified diffusion, which plays an important role in the cavitation bubble growth, is taken into account. A focused ultrasound lithotripsy using the collapse of cloud cavitation was demonstrated numerically. The cloud cavitation is generated by the high frequency ultrasound waves and is collapsed by the low frequency ultrasound waves. As the result of the si...","PeriodicalId":20469,"journal":{"name":"Proc. Meet. Acoust.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83473926","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":"Demonstration on the nonlinear scattering of crossed ultrasonic beams in presence of single bubble in water","authors":"Katherine A. Haas, M. Korman","doi":"10.1121/2.0000911","DOIUrl":"https://doi.org/10.1121/2.0000911","url":null,"abstract":"An apparatus consisting of an open thin-wall clear acrylic rectangular tank is used to resonate the volume cavity of water in an nx=1, ny=1, nz=3 mode; such that a mm sized bubble or less can be levitated in the center of the tank. The authors will utilize the experimental arrangement suggested by T.J. Asaki, P.L. Marston, and E.H. Trinh [“Shape oscillations of bubbles in water driven by modulated ultrasonic radiation pressure: Observations and detection with scattered laser light,” JASA 93, p 706-713, (1993)]. In which, their experimental apparatus involves a description of their piezoelectric driver, which couples into the bottom of the tank. Next, the demonstration consists of the nonlinear scattering of crossed ultrasonic beams of primary frequency components: f1=1.9 MHz, f2= 2.1 MHz; which, interact nonlinearly with the bubble to produce nonlinear scattering outside the interaction region at the combination frequency f+ = 4.0 MHz. The receiving 4 MHz transducer unit will measure the nonlinear scatter...","PeriodicalId":20469,"journal":{"name":"Proc. Meet. Acoust.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79381491","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":"Multiple-scales analysis on high speed and high frequency pressure waves induced by liquid compressibility in bubbly liquids","authors":"R. Akutsu, T. Kanagawa, Y. Uchiyama","doi":"10.1121/2.0000901","DOIUrl":"https://doi.org/10.1121/2.0000901","url":null,"abstract":"This paper theoretically examines weakly nonlinear propagation of plane progressive waves in an initially quiescent compressible liquid containing many spherical microbubbles. Waves propagate with a large phase velocity exceeding the speed of sound in a pure water, which is induced by the incorporation of compressibility of the liquid phase. For simplicity, the wave dissipation owing to viscosity in the gas phase and heat conduction in the gas and liquid phases are ignored, and wave dissipation is thereby owing to the liquid viscosity and liquid compressibility. The set of governing equations for bubbly flows is composed of conservation equations of mass and momentum for gas and liquid phases, the equations of motion describing radial oscillations of a representative bubble, and the equation of state for both phases. By using the method of multiple scales and the determination of size of three nondimensional parameters, i.e., the bubble radius versus wavelength, wave frequency versus eigenfrequency of single bubble oscillations, and wave propagation speed versus sound speed in pure liquid in terms of small but finite wave amplitude (i.e., perturbation), we can derive a nonlinear wave equation describing the wave behavior at a far field.This paper theoretically examines weakly nonlinear propagation of plane progressive waves in an initially quiescent compressible liquid containing many spherical microbubbles. Waves propagate with a large phase velocity exceeding the speed of sound in a pure water, which is induced by the incorporation of compressibility of the liquid phase. For simplicity, the wave dissipation owing to viscosity in the gas phase and heat conduction in the gas and liquid phases are ignored, and wave dissipation is thereby owing to the liquid viscosity and liquid compressibility. The set of governing equations for bubbly flows is composed of conservation equations of mass and momentum for gas and liquid phases, the equations of motion describing radial oscillations of a representative bubble, and the equation of state for both phases. By using the method of multiple scales and the determination of size of three nondimensional parameters, i.e., the bubble radius versus wavelength, wave frequency versus eigenfrequency of sin...","PeriodicalId":20469,"journal":{"name":"Proc. Meet. Acoust.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76161153","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":"Simulation of shear shock waves in the human head for traumatic brain injury","authors":"B. Tripathi, G. Pinton","doi":"10.1121/2.0000894","DOIUrl":"https://doi.org/10.1121/2.0000894","url":null,"abstract":"We have recently observed, experimentally, that shear shock waves are generated deep inside the brain starting from a low initial acceleration (sub-concussive range). This observation has motivated the development of simulation tools to model shear shock waves in the human head. Current numerical methods that describe nonlinear shear wave propagation are in retarded time which makes them unidirectional, and they are valid for small angles only. A full-wave model would capture a much wider range of shock wave physics that occurs during a traumatic event. Here we present: 1) a nonlinear system of conservation laws that models the propagation of linearly-polarized shear waves in 2D, 2) a model of the attenuation/dispersion in soft solids using relaxation mechanisms, 3) numerical simulations of (1)-(2) using the Piecewise Parabolic Method (PPM). This system is solved using an un-split and conservative implementation of PPM with a local Lax-Friedrichs flux, coupled with second-order splitting in time. The 2D m...","PeriodicalId":20469,"journal":{"name":"Proc. Meet. Acoust.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91092283","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}