Radio Physics and Radio Astronomy最新文献

{"title":"GROUND BASED SUPPORT OF THE SPACE MISSION PARKER PERFORMED WITH UKRAINIAN LOW FREQUENCY RADIO TELESCOPES","authors":"V. Dorovskyy, V. Melnik, A. Brazhenko","doi":"10.15407/rpra28.02.117","DOIUrl":"https://doi.org/10.15407/rpra28.02.117","url":null,"abstract":"Subject and Purpose. The sporadic radio emissions coming from the Sun in a broad frequency range contain a lot of important information concerning the solar corona, parameters of the radio frequency sources therein, and the parameter variations resulting from active processes on and about the Sun. These have been the reasons for recent launches of the space missions intended for stud- ying the Sun and its corona, such as the Parker Solar Probe (PSP) and the Solar Orbiter. The present work is aimed at demonstrating effectiveness of the ground-based support for the space missions, the PSP before all, which is provided by the large Ukrainian radio telescopes of the decameter wavelength range. Another purpose has been cross-calibration of the space-borne radiometer against calibrated data from a ground-based instrument. Methods and Methodology. One of the remote diagnosis techniques widely used with respect to the solar corona is to analyze parameters of the radio frequency emissions from sources lying at a variety of altitudes within the corona. The methodology of such joint, space-borne/terrestrial investigations suggests simultaneous observations of certain individual events during closest approach of the space probe PSP to the Sun, with analysis over a widest possible frequency range. The data obtainable within overlapping fre- quency bands are proposed for calibrating the on-board radio receivers of the space probe. Results. The methodology proposed for joint, space-based / terrestrial observations has been substantiated. Data from the UTR-2 and URAN-2 radio telescopes and the space probe PSP have been used to plot the dynamic and the polarization spectra of the June 9, 2020 solar bursts, with identification and comparison of the relevant individual events. A joint dynamic spectrum of these bursts has been obtained for the frequency band of 0.5 to 32 MHz. The calibrated data from the ground-based radio telescopes have allowed performing cross-calibration of the HF receiver in the FIELDS-PSP data taking module within the frequency band of 10 to 18 MHz. Conclusions. The paper has provided evidence of an effective ground-based support for the space mission PSP on the part of large Ukrainian radio telescopes. Examples of joint observations have been given, and a methodology described which is employed for cross-calibrating the HF receivers of the FIELD-PSP module. Prospects are outlined of further ground-based support for solar space research missions.","PeriodicalId":33380,"journal":{"name":"Radio Physics and Radio Astronomy","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45523290","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":"A STUDY OF MATERIAL RECOGNITION ACCURACY BY RADIO WAVE METHODS","authors":"V. Ovsyannikov, M. Gorobets, V. Gerasimov","doi":"10.15407/rpra28.03.234","DOIUrl":"https://doi.org/10.15407/rpra28.03.234","url":null,"abstract":"Subject and Purpose. Accuracy of the material recognition using radio wave methods in the ultra-high frequency band for substanc- es with dielectric properties is the present paper concern. To estimate a total error arising in material measurements by the radio wave method and determine constituents of the error is the aim of the work. Methods and Methodology. The material recognition accuracy is estimated by the method of statistical analysis in terms of average statistical deviation and dispersion. Results. Advantages and disadvantages of the waveguide method in which a test material sample is placed inside a metal waveguide have been traced, suggesting an obvious drawback that the material recognition process of the sort is difficult to be automated. In the remote inspection procedure, the test material is in free space (e.g. on a conveyor) where it is illuminated with a microwave transmitting antenna. The receiving antenna is located on the other side of the test sample and transfers the received signal to the apparatus for determining material parameters. There, the attenuation coefficient is measured as the electromagnetic wave passes through the sample. The measurement results show a correlation dependence of the wave attenuation coefficient on the quality of the substance, enabling us to use frequency dependences of the material to reveal its unknown quality. The remote method makes it possible to automate the recognition of materials with dielectric properties. For these methods mentioned right above, random error values arising during the material recognition were estimated by the method of statistical analysis. Conclusions. The analysis of errors in the material recognition shows that the total error ranges from 7.28 to 12.74% with corresponding constituent errors including faults of today’s microwave measuring devices, inappropriate application of the method or unsuitable type of the structural model of the parameter determination, and errors in data calculations.","PeriodicalId":33380,"journal":{"name":"Radio Physics and Radio Astronomy","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135494652","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":"SELECTION OF SHF-BACKSCATTERING MODEL OF THE SEA SURFACE WITH REGARD TO SHADOWING","authors":"A. Bukin, V. Gutnik, Yu. Lohvinov, N. Reznichenko","doi":"10.15407/rpra28.03.224","DOIUrl":"https://doi.org/10.15407/rpra28.03.224","url":null,"abstract":"Subject and Purpose. The article is devoted to the analysis of theoretically and experimentally obtained values of the specific effective sea-scattering surface in the region of super-high-frequencies (SHF). The study is reasoned by the need to know characteristics of the electromagnetic wave scattering from various objects at the modeling stage. The focus is on the choice of backscattering model with a methodology of specific effective scattering surface estimation that takes into account the shadowing effect of the sea surface under given conditions. Methods and Methodology. The study is based on mathematical modeling techniques and is accompanied by the comparison of the modeling results with experiment. Results. Proceeding from the simulation results with the effect of sea-surface shadowing taken into account and relying on the check of consistency with the measured data, a comparison analysis has been performed among theoretical models of specific effective sea-scattering surface calculation at low grazing angles. Conclusion. Analysis has been given to the specific effective sea-scattering surface obtained by the facet and two-scale models and to the values measured by experiment. Quantitative estimates of the specific effective scattering surface have been obtained with the shadowing effect of the sea surface taken into account. Analysis of the quantitative estimates has been carried out.","PeriodicalId":33380,"journal":{"name":"Radio Physics and Radio Astronomy","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135496226","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":"NON-REFLECTIVE INCIDENCE OF P-POLARIZED ELECTROMAGNETIC WAVES ON THE SOLID-STATE STRUCTURE \"UNIAXIAL PLASMONIC METASURFACE — DIELECTRIC LAYER — METAL\"","authors":"Хвилі В Плазмі, Waves IN Plasmas, I. Popovych","doi":"10.15407/rpra28.02.166","DOIUrl":"https://doi.org/10.15407/rpra28.02.166","url":null,"abstract":"Subject and Purpose. The solid-state structures involving metasurfaces can be used to effectively control some of the basic properties of electromagnetic waves, like amplitude, phase and polarization. The present work is aimed at analyzing the new effects that may appear during incidence of p-polarized electromagnetic waves upon a solid-state structure involving a uniaxial plasmonic metasurface, a dielec- tric interlayer, and a layer of metal. Methods and Methodology. The conditions suitable for identifying the effects that result from the reflection of a p-polarized electro- magnetic wave incident upon a solid-state structure of the above described type have been sought for via numerical simulation. That has allowed finding the magnitudes of the essential parameters, such as angles of incidence and frequencies of the electromagnetic waves, as well as thicknesses of the dielectric interlayer, that could stipulate appearance of novel electromagnetic effects. Results. It has been shown that the solid-state structure involving a uniaxial plasmonic metasurface, a dielectric interlayer, and a layer of metal is capable, under certain conditions, to fully absorb an incident electromagnetic wave of p-polarization. Moreover, a new effect has been predicted, specifically that of full conversion of the incident p-polarized electromagnetic wave into a reflected wave of s-polariza- tion. The necessary condition is that the plane of incidence of the electromagnetic wave were at an acute angle to the principal symmetry axis of the plasmonic metasurface. Conclusions. The solid-state structures of the type involving a uniaxial plasmonic metasurface, a dielectric interlayer, and a layer of metal are characterized by unique reflective properties. They are capable of fully absorbing, under certain conditions, the p-polarized electromagnetic waves incident upon them. Such structures can be used for creating optical and nanoelectronic devices of new types.","PeriodicalId":33380,"journal":{"name":"Radio Physics and Radio Astronomy","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67142305","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":"MODERNIZATION OF THE KHARKIV MICROWAVE SPECTROMETER: CURRENT STATE","authors":"E. Alekseev, V. Ilyushin, V. Budnikov, M. Pogrebnyak, L. Kniazkov","doi":"10.15407/rpra28.03.257","DOIUrl":"https://doi.org/10.15407/rpra28.03.257","url":null,"abstract":"Subject and Purpose. Results are presented of the recent considerable upgrade implemented at the Kharkiv microwave spectrometer. The upgrade has been aimed at extending the operating frequency range and increasing the utmost accessible spectral resolution of the spectrometer. Methods and Methodology. In order to extend the frequency range we have designed and constructed new BWO-based oscillator units, also providing for possibility of frequency tripler application. Construction of a new absorbing cell of enlarged diameter allowed us to considerably improve the spectral resolution for Lamb-dip measurements. Results. Owing to the upgrade, the spectrometer has become able to cover the frequency range from 34 to 420 GHz, with a gap from 183 to 200 GHz. The spectral resolution in the Lamb-dip observation mode has been increased by a factor of two. In addition, the functionality of the spectrometer has been significantly improved via modernization of several of its subsystems. Conclusions. The new upgrades of the spectrometer systems have permitted extending the operational frequency range and increasing the utmost accessible resolution by means of reducing the time-of-flight line broadening in the Lamb-dip measurements. In addition, application of square-wave frequency modulation with accurately known modulation parameters, in combination with careful modeling of the distortions caused by reflections in the absorbing cell, has allowed us to significantly improve the accuracy of line frequency measurements.","PeriodicalId":33380,"journal":{"name":"Radio Physics and Radio Astronomy","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135494865","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 TE01 WAVE EXCITATION IN A CIRCULAR WAVEGUIDE USING HIGHER-ORDER MODES OF AN OPEN RESONATOR","authors":"I. Kuzmichov, O. Кogut, B Muzychishin, O. Popkov, O. Senkevych","doi":"10.15407/rpra28.03.243","DOIUrl":"https://doi.org/10.15407/rpra28.03.243","url":null,"abstract":"Subject and Purpose. Peculiarities of the TE01 wave excitation in a circular waveguide located in the center of the flat mirror of a hemispherical open resonator (OR) are studied using the OR oscillation type TEM30q and the OR degenerate oscillation type TEM in the extremely high frequency (EHF) range. Methods and Methodology. The efficiency of the circular-waveguide TE01 wave excitation using the TEM30q and TEM11q types of OR oscillations is evaluated through the factor of antenna surface utilization. Amplitude distributions of the OR oscillation fields were measured by the trial body method. Results. It has been established that the efficiency, h, of the TE01 wave excitation in the circular waveguide is not high when it is by use of the OR oscillation ТЕМ30q. Things are different when the TE01 wave is excited with the inner ring of the TEM11q degenerate oscillation field whereby the h value shoots up to 95.5%, the circular waveguide section radius being a = 0.993w0, where w0 is the radius of the field spot of the main oscillation type TEM00q on the OR flat mirror. The experimental studies have confirmed that the TE01 wave excitation in the waveguide has high efficiency. The attachment of the circular oversized waveguide section worsens the OR loss by no more than 0.9 dB. The presence of the circular waveguide makes the TEM3012 oscillation type transform into the TEM1112 degenerate oscillation. Conclusions. The considered OR can be used as a storage resonator in the construction of electromagnetic pulse compressors in the EHF range, since the resonant system loss increases insignificantly, and the circular waveguide itself is oversized. It is easy to implement an interference switch in such a waveguide.","PeriodicalId":33380,"journal":{"name":"Radio Physics and Radio Astronomy","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135496222","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 DUAL-FREQUENCY INTERFEROMETRY APPLICABILITY FOR TARGET ELEVATION ANGLE MEASUREMENT USING TWO-COORDINATE RADARS","authors":"V. Galushko, O. Vlasenko, Y. Bulakh","doi":"10.15407/rpra28.02.143","DOIUrl":"https://doi.org/10.15407/rpra28.02.143","url":null,"abstract":"Subject and Purpose. The study deals with the dual-frequency radio interferometry technique, which is based on the employment of two fairly close frequencies with the aim to remove ambiguity of the radar target elevation estimation using 2D-radar and eliminate 2 pm-uncertainty of the signal phase difference measurement. Analysis of random noise action on the accuracy of the elevation angle estimation by the dual-frequency radio interferometry and assessment of practical applicability of the method make up the purpose of the paper. Methods and Methodology. The noise action on the elevation angle measurement accuracy is examined through a series of an- alytical calculations with the use of statistical analysis methods. The noise in each receiving channel is modeled in terms of additive, statistically independent stationary Gaussian processes with zero mean values and equal variances. The calculation results are checked via computer simulations with statistics estimations for 106 random noise realizations. Results. A correct condition has been developed for the sector width where the target elevation angle is unambiguously estimated depending on the space separation of the antennas (baselines) and the frequency ratio. Expressions for elevation angle estimation errors have been obtained, showing that the error is mainly contributed by the faults in the determination of the ambiguity interval number. A probability of the correct determination of the ambiguity interval number has been derived depending on the signal- to-noise ratio and the frequency difference, indicating that almost one hundred per cent probability of the correct determination of the ambiguity interval number is only achieved when the signal-to-noise ratio exceeds 30 dB. A comparative analysis has been performed between the methods of dual-frequency interferometry and conventional phase-difference direction finding in the case of close X-band frequencies and the same sectors of survey. Conclusions. The dual-frequency radio interferometry technique with close frequencies has been shown to outperform the stand- ard phase-difference direction-finding method only when the signal-to-noise ratio is sufficiently high (over 30 dB). In principle, the accuracy of the technique seems possible to improve by taking significantly different frequencies selected with regard to the scale negotiation condition. However, it should be mentioned that the implementation of the relevant algorithm in practice is much more complicated than the conventional scheme with a single frequency and several antenna baselines.","PeriodicalId":33380,"journal":{"name":"Radio Physics and Radio Astronomy","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67142256","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":"OMNIDIRECTIONAL MILLIMETER-WAVELENGTH ANTENNAS BASED ON SEGMENTAL DIELECTRIC RESONATORS WHICH SUPPORT WHISPERING GALLERY MODES","authors":"A. Kogut, I. Kuzmychov, G. Annino, R. Dolia, S. Nosatiuk, E. Kogut, V. Derkach, Y. Ostryzhnyi","doi":"10.15407/rpra28.01.071","DOIUrl":"https://doi.org/10.15407/rpra28.01.071","url":null,"abstract":"Subject and Purpose. The subject of investigation is a new class of resonant-type transmit antennas intended for operation at millimeter wavelengths. The model under consideration is based on the idea of diffractional re-emission of waves into the azimuthal direction by local inhomo-geneities of the basically cylindrical structure. The purpose of the work is to justify the possibility of using such an effect for creating antennas with a circular radiation pattern, and to suggest an appropriate design. Methods and Methodology. The research program included both experimental work and application of advanced computer simulation techniques. The modern methods employed have allowed studying electromagnetic field distributions both in internal domains of the dielectric resonators and in the far-field zones of the resonator-based antennas. Results. Design solutions have been proposed for resonant-type, omnidirectional transmit antennas to operate in the millimeter waveband. The characteristic parameters are sizes of their radiating elements, specifically the segmental members equidistantly disposed along the azimuthal direction on the cylindrical surfaces of dielectric disks. The radiational characteristics of such antennas, with segments of either localized or extended dimension (compared with the operating wavelength) have been investigated. Electric field intensity distributions in the far-field region and the respective gain factors of the antennas have been studied. Conclusions. The antennas based on segmental dielectric resonators have been shown to form multi-lobe radiation patterns covering the angular sector of 0–360 along the azimuth. By placing the local segments at the resonant field’s antinodes (of the operating mode) it is possible to achieve relatively high values of the gain, reaching 15.5 dB at the lobe maxima","PeriodicalId":33380,"journal":{"name":"Radio Physics and Radio Astronomy","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67142067","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":"INFLUENCE OF GLOBAL SEISMIC ACTIVITY ON IONOSPHERE AND NEAR-EARTH ATMOSPHERE PARAMETERS","authors":"I. Zakharov, L. Chernogor","doi":"10.15407/rpra28.02.130","DOIUrl":"https://doi.org/10.15407/rpra28.02.130","url":null,"abstract":"Subject and Purpose. The catastrophic magnitude of life and monetary losses associated with earthquakes spurs extensive searches for reliable earthquake precursors. It is common knowledge that lithospheric processes have a direct bearing on the state of atmosphere and ionosphere during earthquakes. However, the usual practice is to enquire things in the immediate vicinity of the hypocenter, notwithstanding the global nature of seismic processes. The present work is different as considers the changes of pressure and temperature in the near-Earth atmosphere and the total electron content (TEC) in the ionosphere for world regions at arbitrary distances from hypocenters of strong earthquakes. Methods and Methodology. Employed are the data from the maps of the ionospheric TEC and the maps of the pressure and temperature in the atmospheric surface layer in world regions of 40°N latitude. The quantitative estimates are provided by the superposed epoch analysis for winter seasons between 2012 to 2018. Days of strong earthquakes of the Richter magnitudes within 6.3 to 7.9 are taken for the \"zeros\" whatever the geographical coordinates of the event. Results. The near-Earth atmosphere pressure P0 shows a decrease for about 5 days before the earthquake and gets elevated for about 5 days after the event. The air temperature T behaves in the opposite way. The TEC shows a sharp increase 2 to 5 days before the earthquake. The typical deviations DP0 and DT are of up to 2 hPa and 0.3 K, respectively. The TEC deviations, DTEC, are within 3 to 4%. Where the longitudes fall on the lithosphere plate boundaries, these deviations are nearly doubled. Also, the magnitude of the effect is higher in the regions where the atmospheric pressure is lower. The established patterns indicate that the gas release from underground plays an important role in the lithosphere-atmosphere and lithosphere-ionosphere interaction effects. In this case, the main part is played by radon fluxes that initiate the near-Earth atmosphere ionization and trigger a whole chain of secon- dary processes. Conclusions. The results of the work indicate that atmospheric and ionospheric effects caused by lithospheric processes take place at arbitrary distances from strong earthquake hypocenters. Gaseous emissions from underground play an important role as a primary factor of these global effects.","PeriodicalId":33380,"journal":{"name":"Radio Physics and Radio Astronomy","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67142216","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":"NEAR THE ORIGINS OF MILLIMETER WAVE RADAR (90-th anniversary of Vadym В. Razskazovsky)","authors":"O. Kostenko, Yu. F. Logvinov, Y. Pedenko","doi":"10.15407/rpra28.02.174","DOIUrl":"https://doi.org/10.15407/rpra28.02.174","url":null,"abstract":"This paper is dedicated to the 90-th anniversary of Vadym Borysovych Razskazovsky, an outstanding scientist in the fields of radio engineering and radio science, holder of the titles and positions like DSc (Engineering), Professor, and Head of the Statistical radio physics department at the O.Ya. Usikov Institute for Radio Physics and Electronics within the Academy of Sciences of Ukraine.","PeriodicalId":33380,"journal":{"name":"Radio Physics and Radio Astronomy","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67142316","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}