Ultrasonics最新文献

{"title":"Improving the signal-to-noise ratio of the laser ultrasonic synthetic aperture focusing technique to detect submillimeter internal defects using echo array similarity","authors":"Huabin He,&nbsp;Jianguo He,&nbsp;Zhihui Xia,&nbsp;Kaihua Sun,&nbsp;Chao Wang,&nbsp;Qian Liu","doi":"10.1016/j.ultras.2024.107513","DOIUrl":"10.1016/j.ultras.2024.107513","url":null,"abstract":"<div><div>Laser ultrasonic imaging is a promising technique for structural health monitoring because it is noncontact and nondestructive. However, this technique will only find more industrial applications if it has a high signal-to-noise ratio (SNR) and short data acquisition time. In existing delay-and-sum algorithms, such as the synthetic aperture focusing technique (SAFT) and the total focusing method, a higher SNR requires more A-scan signals, which mean a longer data acquisition time. It is difficult for these algorithms to consider these two aspects simultaneously. Thus, in this study, we propose a post-processing algorithm that extracts neglected information from laser ultrasonic B-scan data to improve the SNR of the SAFT without increasing the data acquisition time. The SNR was increased by multiplying the SAFT image intensity with the echo array similarity defined using the directivity and echo shape information of laser ultrasound. In experiments, SNR was increased from 4.1 dB to 31.3 dB for two submillimeter defects having a diameter of 0.5 mm and depth of 15 mm. Deeper defects can be detected because of the improved SNR. In this study, two submillimeter defects with a depth of 30 mm were detected. Compared with existing delay-and-sum algorithms, the proposed algorithm performs well in terms of both SNR and data acquisition time, which can promote its use in more industrial applications.</div></div>","PeriodicalId":23522,"journal":{"name":"Ultrasonics","volume":"146 ","pages":"Article 107513"},"PeriodicalIF":3.8,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142628965","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Research on the second-harmonic focused ultrasonic device based on micro-bubble contrast agents","authors":"Qinglei Zeng ,&nbsp;Yuetongxu Li ,&nbsp;Zhaoyu Deng ,&nbsp;Gutian Zhang ,&nbsp;Chengwei Zhang ,&nbsp;Haifeng Huang ,&nbsp;Xiaozhou Liu","doi":"10.1016/j.ultras.2024.107514","DOIUrl":"10.1016/j.ultras.2024.107514","url":null,"abstract":"<div><div>Non-invasive, accurate diagnosis and treatment have increasingly gained attention in medical research. The nonlinear response mechanism of ultrasound contrast agents and their medical application have become major topics in ultrasound imaging studies. This paper reports on a second-harmonic focused ultrasonic device based on micro-bubble contrast agents, which is designed to solve the problems associated with a weak second-harmonic intensity. A periodic array of circular holes is embedded in the center of a specifically shaped resin plate, and contrast agents are encapsulated in the circular holes using thin resin tape. The functional mechanism is theoretically explained and experimentally verified. This device enables second-harmonic ultrasound imaging with a higher ultrasonic lateral resolution and signal-to-noise ratio than the conventional system without the device.</div></div>","PeriodicalId":23522,"journal":{"name":"Ultrasonics","volume":"146 ","pages":"Article 107514"},"PeriodicalIF":3.8,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142628972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimal transport assisted full waveform inversion for multiparameter imaging of soft tissues in ultrasound computed tomography","authors":"Xiaoqing Wu ,&nbsp;Yubing Li ,&nbsp;Chang Su ,&nbsp;Panpan Li ,&nbsp;Weijun Lin","doi":"10.1016/j.ultras.2024.107505","DOIUrl":"10.1016/j.ultras.2024.107505","url":null,"abstract":"<div><div>Ultrasound computed tomography (USCT) has emerged as a promising platform for imaging tissue properties, offering non-ionizing and operator-independent capabilities. In this work, we demonstrate the feasibility of obtaining quantitative images of multiple acoustic parameters (sound speed and impedance) for soft tissues using full waveform inversion (FWI), which are justified with both numerical and experimental cases. A 3D reconstruction based on a series of 2D slice images is presented for the experimental case of ex vivo soft tissues. To improve the robustness of the reconstruction process, a hierarchical FWI strategy is adopted, gradually iterating from low to high frequencies. In parallel, we employ a graph-space optimal transport misfit function, avoiding convergence into local minima and minimizing inversion artifacts caused by skin-related supercritical reflections. Our method first carries out sound speed inversion based on transmitted waves in the low and middle frequency bands, and then uses all types of waves in the high frequency band for simultaneous inversion of both sound speed and impedance. Compared to conventional strategies, the proposed approach can accurately reconstruct physical models consistent with the actual soft tissue sample. These high-resolution ultrasound images of acoustic parameters are promising to allow for quantitative differentiation among different types of tissues (e.g., muscles and fats). These results have significant implications for advancing our understanding of tissue properties and for potentially contributing to disease diagnosis through USCT, which is a flexible and cost-effective alternative to X-ray computed tomography or magnetic resonance imaging at no significant sacrifices for resolution.</div></div>","PeriodicalId":23522,"journal":{"name":"Ultrasonics","volume":"147 ","pages":"Article 107505"},"PeriodicalIF":3.8,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142745898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ultrafast 3D synthetic aperture imaging with Hadamard-encoded aperiodic interval codes and aperiodic sparse arrays with separate transmitters and receivers","authors":"Tarek Kaddoura,&nbsp;Mohammad Hadi Masoumi,&nbsp;Roger Zemp","doi":"10.1016/j.ultras.2024.107497","DOIUrl":"10.1016/j.ultras.2024.107497","url":null,"abstract":"<div><div>3D synthetic aperture (SA) imaging of volumes can be obtained using sparse 2D ultrasound arrays. However, even with just 256 elements, the volumetric imaging rate can be relatively slow due to having to transmit on each element in succession. Hadamard Aperiodic Interval (HAPI) codes can be used to image the full SA dataset in one extended transmit to speed up the synthetic aperture imaging, but their long nature produces large deadzones if the same elements are used as both transmitters and receivers. In this simulation study, we use a 2D Costas sparse array with separate transmitters and receivers to remedy the deadzone problem, and use it with the HAPI-coded imaging scheme to obtain fully transmit–receive focused, wide field-of-view 3D volumes with high-resolution and high SNR at ultrafast volumetric imaging rates of more than 500 volumes per second, almost nine times faster than non-coded SA imaging with the same imaging parameters. We show similar PSF performance compared to non-coded SA, and a 26 dB improvement in SNR with order-256 HAPI codes. We also present cyst simulations showing similar contrast for the HAPI-coded SA method compared to non-coded SA in the context of no noise, and improved contrast in the context of noise.</div></div>","PeriodicalId":23522,"journal":{"name":"Ultrasonics","volume":"147 ","pages":"Article 107497"},"PeriodicalIF":3.8,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142682924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Generation of broadband airborne ultrasound using an Harmonic Acoustic Pneumatic Source","authors":"Romain Rousseau,&nbsp;Pierre Grandjean,&nbsp;Nicolas Quaegebeur,&nbsp;Loïc Charlebois-Vachon,&nbsp;Philippe Micheau","doi":"10.1016/j.ultras.2024.107494","DOIUrl":"10.1016/j.ultras.2024.107494","url":null,"abstract":"<div><div>This paper presents a new type of airborne transducer for generating broadband ultrasound with a high Sound Pressure Level (SPL). The concept is based on the Harmonic Acoustic Pneumatic Source (HAPS) that uses pressurized air in conjunction with a flow chopper made up of a rotating cage with slots connected to a specific exhaust. The fundamental frequency depends on the number of slots and the rotation speed of the cage. An analytical model of the HAPS coupled with a numerical model of the exhaust is used to predict the radiated acoustic pressure and to estimate the influence of dimensional parameters on pressure level generated by the source. Experiments are conducted with two cages: one with one slot in order to generate pulses periodically and one with <span><math><mrow><mn>122</mn></mrow></math></span> slots to generate periodic sound. The level of sound pressure is measured as a function of distance (<span><math><mrow><mn>0</mn><mo>.</mo><mn>004</mn></mrow></math></span> to <span><math><mrow><mn>0</mn><mo>.</mo><mn>5</mn></mrow></math></span> m), the cage rotation (up to <span><math><mrow><mn>11</mn></mrow></math></span> krpm) and directivity (<span><math><mn>0</mn></math></span> to <span><math><mrow><mn>90</mn></mrow></math></span>°). For the fundamental frequency at <span><math><mrow><mn>22</mn></mrow></math></span> kHz, the maximum SPL of <span><math><mrow><mn>150</mn></mrow></math></span> dB (<span><math><mrow><mn>632</mn></mrow></math></span> Pa rms) is /measured at <span><math><mrow><mn>0</mn><mo>.</mo><mn>004</mn></mrow></math></span> m, and decreases to <span><math><mrow><mn>122</mn></mrow></math></span> dB (<span><math><mrow><mn>35</mn></mrow></math></span> Pa rms) at <span><math><mrow><mn>0</mn><mo>.</mo><mn>5</mn></mrow></math></span> m. At <span><math><mrow><mn>0</mn><mo>.</mo><mn>5</mn></mrow></math></span> m, the second and third harmonics can generate a SPL equal or greater than <span><math><mrow><mn>115</mn></mrow></math></span> dB above <span><math><mrow><mn>22</mn></mrow></math></span> kHz and up to <span><math><mrow><mn>66</mn></mrow></math></span> kHz. Discrepancies between the experiments results and numerical model are observed in terms of SPL, directivity and in-axis pressure.</div></div>","PeriodicalId":23522,"journal":{"name":"Ultrasonics","volume":"146 ","pages":"Article 107494"},"PeriodicalIF":3.8,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142628951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ultrafast laser-enabled optoacoustic characterization of three-dimensional, nanoscopic interior features of microchips","authors":"Yi He ,&nbsp;Guojie Luo ,&nbsp;Jie Huang ,&nbsp;Yehai Li ,&nbsp;Hoon Sohn ,&nbsp;Zhongqing Su","doi":"10.1016/j.ultras.2024.107510","DOIUrl":"10.1016/j.ultras.2024.107510","url":null,"abstract":"<div><div>The recent advances in micromanufacturing have been pushing boundaries of the new generation of semiconductor devices, which, in the meantime, brings new challenges in the material and structural characterization – a key step to ensure the device quality through the micromanufacturing process. An ultrafast laser-enable optoacoustic characterization methodology is developed, targeting <em>in situ</em> calibration and delineation of the three-dimensional (3-D), nanoscopic interior features of opaque semiconductor chips. With the guidance of ultrafast electron–phonon coupling effect and velocity-perturbated optical interference, a femtosecond-laser pump–probe set-up based on Sagnac interferometer is configured to generate and acquire picosecond ultrasonic bulk waves (P-UBWs) traversing the microchips. The interior features of the microchips shift the phase of acquired P-UBW signals, reflected in the perturbed probe laser beam. The phase shifts are calibrated to compute signal correlation of P-UBW signals between different acquiring positions, whereby to delineate the interior features in an intuitive manner. The approach is experimentally validated by characterizing nanoscopic, invisible interior aurum(Au)-gratings with periodically varied depths in typical microchips. Results highlight that the 3-D nanoscopic features of the microchips can be revealed with a microscopic and a nanoscopic spatial resolution, respectively along the transverse and depth directions of the chip, where the Au-gratings become “visible” with a depth variance of a few tens of nanometers only. This proposed approach has provided a fast, nondestructive approach to “see” through an opaque microchip with a nanoscopic resolution.</div></div>","PeriodicalId":23522,"journal":{"name":"Ultrasonics","volume":"146 ","pages":"Article 107510"},"PeriodicalIF":3.8,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142628988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An algorithm for multi-damage size estimation of composite laminates","authors":"Zhongyan Jin ,&nbsp;Qihong Zhou ,&nbsp;Zeguang Pei ,&nbsp;Ge Chen","doi":"10.1016/j.ultras.2024.107511","DOIUrl":"10.1016/j.ultras.2024.107511","url":null,"abstract":"<div><div>Localization and size estimation of composite damage are challenging but essential for composite performance evaluation. This paper proposes a new methodology for the size estimation of multi-damage in composite laminates using Lamb wave technology. The pure A₀ modal of Lamb wave is excited to avoid dispersion and multi-modal effects of Lamb wave. An extraction algorithm is introduced to obtain the first wave packet and time-of-flight. According to the results obtained by the extraction algorithm, the Bayesian-hybrid localization algorithm based on the reconstruction algorithm for probabilistic inspection of damage and modified delay-and-sum (MDAS) is performed to localize damages. The damage boundaries are obtained through convex enveloping a series of damage boundary points identified by MDAS. An adaptive Gaussian mixture model based on Akaike’s Information Criterion and Bayesian Information Criterion is designed to remove abnormal boundary points. The proposed method is numerically investigated and validated through multi-damage experiments. The results demonstrate that it can accurately estimate the locations and boundaries of multi-damage in composite laminates.</div></div>","PeriodicalId":23522,"journal":{"name":"Ultrasonics","volume":"146 ","pages":"Article 107511"},"PeriodicalIF":3.8,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142628949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Band edge modulation for high-performance LL-SAW resonators on LiNbO3/SiC by introducing an ultra-thin intermediate oxide layer","authors":"Juxing He ,&nbsp;Shibin Zhang ,&nbsp;Pengcheng Zheng ,&nbsp;Xiaoli Fang ,&nbsp;Hulin Yao ,&nbsp;Mijing Sun ,&nbsp;Dongchen Sui ,&nbsp;Yanlong Yao ,&nbsp;Chongxi Song ,&nbsp;Zheng Zhou ,&nbsp;Xin Ou","doi":"10.1016/j.ultras.2024.107508","DOIUrl":"10.1016/j.ultras.2024.107508","url":null,"abstract":"<div><div>With the exploding demand of rapid information transmission, high-frequency acoustic filtering devices are becoming an immediate need. Longitudinal leaky surface acoustic wave (LL-SAW) devices with unique advantages can be a promising platform. In this paper, we introduce a 100 nm intermediate oxide layer into the X-cut lithium niobate on silicon carbide (LiNbO₃/SiC) to improve the in-band performance of LL-SAW resonators. First, the dispersion curves of the structures are analyzed by finite element method. In this part, we successfully interpret the intrinsic low quality factor (<em>Q</em>) of LL-SAW on LiNbO₃/SiC in general design, and predict the enhancement of <em>Q</em> by introducing an intermediate oxide layer without degradation on spurious response. Then, one port resonators considered in the simulation are fabricated and measured. As a result, enhancements in <em>Bode Q</em> among the whole passband are confirmed. Compared with devices state of art, resonators with leading performances are demonstrated. The fabricated resonators have peak-valley admittance ratio of 63.87 dB, <em>Bode Q</em> of ∼300 at <em>f_r</em> and ∼530 at <em>f_ar</em>, <span><math><mrow><msubsup><mtext>k</mtext><mrow><mtext>eff</mtext></mrow><mtext>2</mtext></msubsup><mspace></mspace><mtext>of</mtext></mrow></math></span> 15.66 % and phase velocity of 6187.3 m/s. Additionally, the resonant frequency of SH1 mode shifts to higher frequency. This work enables the design of next generation high frequency mobile communication filters.</div></div>","PeriodicalId":23522,"journal":{"name":"Ultrasonics","volume":"146 ","pages":"Article 107508"},"PeriodicalIF":3.8,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142606636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Low-intensity pulsed ultrasound reduces oxidative and endoplasmic reticulum stress in motor neuron cells","authors":"Thi-Thuyet Truong ,&nbsp;Chih-Chung Huang ,&nbsp;Wen-Tai Chiu","doi":"10.1016/j.ultras.2024.107499","DOIUrl":"10.1016/j.ultras.2024.107499","url":null,"abstract":"<div><div>Endoplasmic reticulum (ER) stress is associated with oxidative stress, which is integral to the development of various pathological conditions, including neurodegenerative disorders. In this study, using NSC-34-a hybrid cell line established by fusing motor neuron–rich embryonic spinal cord cells with mouse neuroblastoma cells-we investigated the effects of low-intensity pulsed ultrasound (LIPUS) stimulation on oxidative (reactive oxygen species)/ER stress-induced neurodegeneration. An ultrasound transducer with a center frequency of 1.15 MHz and a spatial peak temporal average intensity of 357 mW/cm² was used for delivering ultrasound (for 8 min, via a water-filled tube) to motor neuron cells seeded in a plastic culture dish. LIPUS stimulation significantly increased the level of the antiapoptotic protein B-cell lymphoma 2 (BCL-2) and inhibited the expression of apoptosis-associated proteins such as BCL-2-associated X protein (BAX), CCAAT/enhancer-binding protein-homologous protein (CHOP), and caspase-12, thus extending the survival of motor neurons. LIPUS stimulation also enhanced Ca²⁺ signaling and activated the Ca²⁺-dependent transcription factors as nuclear factor of activated T cells (NFAT) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). Furthermore, LIPUS stimulation induced the activation of the serine/threonine kinase protein kinase B (AKT). Thus, LIPUS stimulation prevented oxidative/ER stress–mediated mitochondrial dysfunction. In conclusion, as a safe and noninvasive method, LIPUS stimulation can facilitate further development of ultrasound neuromodulation as a tool for neuroscience research.</div></div>","PeriodicalId":23522,"journal":{"name":"Ultrasonics","volume":"146 ","pages":"Article 107499"},"PeriodicalIF":3.8,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142523241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Estimating annulus sealing properties using the flexural wave spectrum in pitch-catch well-logging","authors":"Sander Bøe Thygesen ,&nbsp;Tore Lie Sirevaag ,&nbsp;Sven Peter Näsholm","doi":"10.1016/j.ultras.2024.107491","DOIUrl":"10.1016/j.ultras.2024.107491","url":null,"abstract":"<div><div>Safe oil and gas well operations require appropriate sealing of the annulus casing. Pitch-catch ultrasound logging measurements can be used for well-barrier inspection. In the analysis of such data, an important aspect is to determine whether there is cement or mud behind the casing.</div><div>This paper presents a data processing approach to differentiate between fluid and solid behind the casing from pitch-catch datasets. It is based on the spectral signature of the casing flexural wave, in which a notch-like dip might be observed. This dip is understood to occur in most solid annulus scenarios. However, when the annulus velocity exceeds a certain limit or is below a threshold, a dip is not produced. The frequency where the dip occurs is associated with an overlap between the flexural phase-velocity and the annulus P-wave velocity. This is exploited by picking the notch frequency, and then its value is used to estimate the annulus material P-wave velocity.</div><div>On the basis of this insight, a method for distinguishing solids from fluids is presented. The outcome is a binary algorithm that detects a dip (or no dip), and which in addition differentiates between annulus materials using the estimated velocity. In addition, we analyze the accuracy of the velocity estimation. It is straightforward to adopt this in an operational setting. This paper demonstrates the performance and accuracy of the algorithm for both simulated data and field recordings.</div></div>","PeriodicalId":23522,"journal":{"name":"Ultrasonics","volume":"146 ","pages":"Article 107491"},"PeriodicalIF":3.8,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142606637","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}