The Astronomy and Astrophysics Review最新文献

{"title":"Radiation environment for future human exploration on the surface of Mars: the current understanding based on MSL/RAD dose measurements","authors":"Jingnan Guo,&nbsp;Cary Zeitlin,&nbsp;Robert F. Wimmer-Schweingruber,&nbsp;Donald M. Hassler,&nbsp;Bent Ehresmann,&nbsp;Scot Rafkin,&nbsp;Johan L. Freiherr von Forstner,&nbsp;Salman Khaksarighiri,&nbsp;Weihao Liu,&nbsp;Yuming Wang","doi":"10.1007/s00159-021-00136-5","DOIUrl":"10.1007/s00159-021-00136-5","url":null,"abstract":"<div><p>Potential deleterious health effects to astronauts induced by space radiation is one of the most important long-term risks for human space missions, especially future planetary missions to Mars which require a return-trip duration of about 3 years with current propulsion technology. In preparation for future human exploration, the Radiation Assessment Detector (RAD) was designed to detect and analyze the most biologically hazardous energetic particle radiation on the Martian surface as part of the Mars Science Laboratory (MSL) mission. RAD has measured the deep space radiation field within the spacecraft during the cruise to Mars and the cosmic ray induced energetic particle radiation on Mars since Curiosity’s landing in August 2012. These first-ever surface radiation data have been continuously providing a unique and direct assessment of the radiation environment on Mars. We analyze the temporal variation of the Galactic Cosmic Ray (GCR) radiation and the observed Solar Energetic Particle (SEP) events measured by RAD from the launch of MSL until December 2020, i.e., from the pre-maximum of solar cycle 24 throughout its solar minimum until the initial year of Cycle 25. Over the long term, the Mars’s surface GCR radiation increased by about 50% due to the declining solar activity and the weakening heliospheric magnetic field. At different time scales in a shorter term, RAD also detected dynamic variations in the radiation field on Mars. We present and quantify the temporal changes of the radiation field which are mainly caused by: (a) heliospheric influences which include both temporary impacts by solar transients and the long-term solar cycle evolution, (b) atmospheric changes which include the Martian daily thermal tide and seasonal CO<span>(_2)</span> cycle as well as the altitude change of the rover, (c) topographical changes along the rover path-way causing addition structural shielding and finally (d) solar particle events which occur sporadically and may significantly enhance the radiation within a short time period. Quantification of the variation allows the estimation of the accumulated radiation for a return trip to the surface of Mars under various conditions. The accumulated GCR dose equivalent, via a Hohmann transfer, is about <span>(0.65 pm 0.24)</span> sievert and <span>(1.59 pm 0.12)</span> sievert during solar maximum and minimum periods, respectively. The shielding of the GCR radiation by heliospheric magnetic fields during solar maximum periods is rather efficient in reducing the total GCR-induced radiation for a Mars mission, by more than 50%. However, further contributions by SEPs must also be taken into account. In the future, with advanced nuclear thrusters via a fast transfer, we estimate that the total GCR dose equivalent can be reduced to about 0.2 sievert and 0.5 sievert during solar maximum and minimum periods respectively. In addition, we also examined factors which may further reduce the radiation dose in spac","PeriodicalId":785,"journal":{"name":"The Astronomy and Astrophysics Review","volume":"29 1","pages":""},"PeriodicalIF":27.8,"publicationDate":"2021-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00159-021-00136-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138514262","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Ultra-light dark matter","authors":"Elisa G. M. Ferreira","doi":"10.1007/s00159-021-00135-6","DOIUrl":"10.1007/s00159-021-00135-6","url":null,"abstract":"<div><p>Ultra-light dark matter is a class of dark matter models (DM), where DM is composed by bosons with masses ranging from <span>(10^{-24}, mathrm {eV}&lt; m &lt; mathrm {eV})</span>. These models have been receiving a lot of attention in the past few years given their interesting property of forming a Bose–Einstein condensate (BEC) or a superfluid on galactic scales. BEC and superfluidity are some of the most striking quantum mechanical phenomena that manifest on macroscopic scales, and upon condensation, the particles behave as a single coherent state, described by the wavefunction of the condensate. The idea is that condensation takes place inside galaxies while outside, on large scales, it recovers the successes of <span>(varLambda )</span>CDM. This wave nature of DM on galactic scales that arise upon condensation can address some of the curiosities of the behaviour of DM on small-scales. There are many models in the literature that describe a DM component that condenses in galaxies. In this review, we are going to describe those models, and classify them into three classes, according to the different non-linear evolution and structures they form in galaxies: the fuzzy dark matter (FDM), the self-interacting fuzzy dark matter (SIFDM), and the DM superfluid. Each of these classes comprises many models, each presenting a similar phenomenology in galaxies. They also include some microscopic models like the axions and axion-like particles. To understand and describe this phenomenology in galaxies, we are going to review the phenomena of BEC and superfluidity that arise in condensed matter physics, and apply this knowledge to DM. We describe how ULDM can potentially reconcile the cold DM picture with the small-scale behaviour. These models present a rich phenomenology that is manifest in different astrophysical consequences. We review here the astrophysical and cosmological tests used to constrain those models, together with new and future observations that promise to test these models in different regimes. For the case of the FDM class, the mass where this model has an interesting phenomenology on small-scales <span>( sim 10^{-22}, mathrm {eV})</span>, is strongly challenged by current observations. The parameter space for the other two classes remains weakly constrained. We finalize by showing some predictions that are a consequence of the wave nature of this component, like the creation of vortices and interference patterns, that could represent a smoking gun in the search of these rich and interesting alternative class of DM models.</p></div>","PeriodicalId":785,"journal":{"name":"The Astronomy and Astrophysics Review","volume":"29 1","pages":""},"PeriodicalIF":27.8,"publicationDate":"2021-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00159-021-00135-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"52317659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Astrophotonics: astronomy and modern optics","authors":"S. Minardi,&nbsp;R. J. Harris,&nbsp;L. Labadie","doi":"10.1007/s00159-021-00134-7","DOIUrl":"10.1007/s00159-021-00134-7","url":null,"abstract":"<div><p>Much of the progress in astronomy has been driven by instrumental developments, from the first telescopes to fiber fed spectrographs. In this review, we describe the field of astrophotonics, a combination of photonics and astronomical instrumentation that is gaining importance in the development of current and future instrumentation. We begin with the science cases that have been identified as possibly benefiting from astrophotonic devices. We then discuss devices, methods and developments in the field along with the advantages they provide. We conclude by describing possible future perspectives in the field and their influence on astronomy.</p></div>","PeriodicalId":785,"journal":{"name":"The Astronomy and Astrophysics Review","volume":"29 1","pages":""},"PeriodicalIF":27.8,"publicationDate":"2021-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00159-021-00134-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"52317273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Composition of organics on asteroid (101955) Bennu","authors":"H. Kaplan, Amy Simon, V. Hamilton, M. Thompson, S. Sandford, M. Barucci, E. Cloutis, J. Brucato, D. Reuter, D. Glavin, B. Clark, J. Dworkin, H. Campins, J. Emery, S. Fornasier, X. Zou, D. Lauretta","doi":"10.1051/0004-6361/202141167","DOIUrl":"https://doi.org/10.1051/0004-6361/202141167","url":null,"abstract":"Context. The Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) mission detected an infrared absorption at 3.4 μm on near-Earth asteroid (101955) Bennu. This absorption is indicative of carbon species, including organics, on the surface. Aims. We aim to describe the composition of the organic matter on Bennu by investigating the spectral features in detail. Methods. We use a curated set of spectra acquired by the OSIRIS-REx Visible and InfraRed Spectrometer that have features near 3.4 μm (3.2 to 3.6 μm) attributed to organics. We assess the shapes and strengths of these absorptions in the context of laboratory spectra of extraterrestrial organics and analogs. Results. We find spectral evidence of aromatic and aliphatic CH bonds. The absorptions are broadly consistent in shape and depth with those associated with insoluble organic matter in meteorites. Given the thermal and space weathering environments on Bennu, it is likely that the organics have not been exposed for long enough to substantially decrease the H/C and destroy all aliphatic molecules.","PeriodicalId":785,"journal":{"name":"The Astronomy and Astrophysics Review","volume":"3 1","pages":""},"PeriodicalIF":25.8,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84733934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Infrared spectra of complex organic molecules in astronomically relevant ice mixtures: IV. Methylamine","authors":"M. Rachid, N. Brunken, D. Boe, G. Fedoseev, A. Boogert, H. Linnartz","doi":"10.1051/0004-6361/202140782","DOIUrl":"https://doi.org/10.1051/0004-6361/202140782","url":null,"abstract":"Context. In the near future, high spatial and spectral infrared (IR) data of star-forming regions obtained by the James Webb Space Telescope may reveal new solid-state features of various species, including more intriguing classes of chemical compounds. The identification of complex organic molecules (COMs) in the upcoming data will only be possible when laboratory IR ice spectra of these species under astronomically relevant conditions are available for comparison. For this purpose, systematic series of laboratory measurements are performed, providing high-resolution IR spectra of COMs. Here, spectra of pure methylamine (CH3NH2) and methylamine-containing ices are discussed. Aims. The work is aimed at characterizing the mid-IR (500–4000 cm−1, 20–2.5 μm) spectra of methylamine in pure and mixed ices to provide accurate spectroscopic data of vibrational bands that are most suited to trace this species in interstellar ices. Methods. Fourier transform infrared spectroscopy is used to record spectra of CH3NH2 in the pure form and mixed with H2O, CH4, and NH3, for temperatures ranging from 15 to 160 K. The IR spectra in combination with HeNe laser (632.8 nm) interference data of pure CH3NH2 ice was used to derive the IR band strengths of methylamine in pure and mixed ices. Results. The refractive index of amorphous methylamine ice at 15 K was determined as being 1.30± 0.01. Accurate spectroscopic information and band strength values are systematically presented for a large set of methylamine-containing ices and different temperatures. Selected bands are characterized and their use as methylamine tracers is discussed. The selected bands include the following: the CH3 antisymmetric stretch band at 2881.3 cm−1 (3.471 μm), the CH3 symmetric stretch band at 2791.9 cm−1 (3.582 μm), the CH3 antisymmetric deformation bands, at 1455.0 and 1478.6 cm−1 (6.873 and 6.761 μm), the CH3 symmetric deformation band at 1420.3 cm−1 (7.042 μm), and the CH3 rock at 1159.2 cm−1 (8.621 μm). Using the laboratory data recorded in this work and ground-based spectra of ices toward YSOs (Young Stellar Objects), upper-limits for the methylamine ice abundances are derived. In some of these YSOs, the methylamine abundance is less than 4% relative to H2O.","PeriodicalId":785,"journal":{"name":"The Astronomy and Astrophysics Review","volume":"156 1","pages":""},"PeriodicalIF":25.8,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74750103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Lithium abundance in a sample of active stars: High-resolution spectrograph observation with the 1.8 m telescope","authors":"L. Xing, Yuanzhi Li, L. Chang, Chuan-jun Wang, J. Bai","doi":"10.1051/0004-6361/202039203","DOIUrl":"https://doi.org/10.1051/0004-6361/202039203","url":null,"abstract":"Context. Observations of young, low-mass, main-sequence, and zero-age main-sequence stars show evidence of a correlation between lithium abundance and chromospheric activity, albeit with a very large scatter. Fast rotation stars (including T Tauri stars, RS CVn, and BY Dra systems) show the Li I doublet at 6707.8Å in their spectra. The lithium depletion is probably related to the rotation (turbulent diffusion induced by rotation). Because the flare activity of stars increases with decreasing rotation period, a correlation can be expected between lithium abundance and chromospheric activity for active stars. Aims. The aim of this paper is to investigate the relation between lithium abundance and the Ca II H and K emission index ( R (cid:48) HK = L HK / L bol ) for a sample of active stars. Methods. Based on the high-resolution spectroscopic observations, we calculated lithium abundance for 14 chromospherically active late-type stars using the comparison of the measured Li I λ 670.8nm equivalent width with curve of growth calculations in non-local- thermodynamic-equilibrium conditions. We also searched the correlation between lithium abundance and the Ca II H & K emission index (log R (cid:48) HK ) for the 14 chromospherically active late-type stars. Results. The study of the relationship between lithium abundance and the Ca II H & K emission index (log R (cid:48) HK ) found that the activ- ity of sample stars increases with increasing lithium abundance. Next, the lithium abundance analogs progressively decrease as the rotation periods increase (rotation becomes slow) and the large values of the log R (cid:48) HK along with small values of Rossby numbers for the sample of chromospherically active stars. Conclusions. The lithium abundance (log N (Li)) versus the chromospheric activity and log N (Li) against the rotation period both indicate that the lithium abundance analogs progressively increase as the chromospheric activity index increases and/or the rotation velocity increase (rotation period becomes small) for our sample of active stars. On the other hand, the log R (cid:48) HK against the Rossby number R O shows that there is a clear trend of increasing activity with increasing rotation velocity for these active stars. Considering that the lithium abundance decreases with increasing stellar age in late-type stars, we can deduce that the chromospheric activity and the rotation velocity both decrease with the increase of stellar age for our sample active stars.","PeriodicalId":785,"journal":{"name":"The Astronomy and Astrophysics Review","volume":"3 1","pages":""},"PeriodicalIF":25.8,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78464725","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"The diffuse interstellar band around 8620 Å. II. Kinematics and distance of the DIB carrier","authors":"H. Zhao, M. Schultheis, Á. Rojas-Arriagada, A. Recio-Blanco, P. Laverny, G. Kordopatis, F. Surot","doi":"10.1051/0004-6361/202141128","DOIUrl":"https://doi.org/10.1051/0004-6361/202141128","url":null,"abstract":"Context. Diffuse interstellar bands (DIBs) are important interstellar absorption features of which the origin is still debated. With the large data sets from modern spectroscopic surveys, background stars are widely used to show how the integrated columns of DIB carriers accumulate from the Sun to great distances. To date, studies on the kinematics of the DIB carriers are still rare. Aims. We aim to make use of the measurements from the Giraffe Inner Bulge Survey (GIBS) and the Gaia–ESO survey (GES) to study the kinematics and distance of the carrier of DIB λ8620, as well as other properties. Methods. The DIBs were detected and measured following the same procedures as in Zhao et al. (2021, A&A, 645, A14; hereafter Paper I), assuming a Gaussian profile. The median radial velocities of the DIB carriers in 38 GIBS and GES fields were used to trace their kinematics, and the median distances of the carriers in each field were estimated by the median radial velocities and two applied Galactic rotation models. Results. We successfully detected and measured DIB λ8620 in 760 of 4117 GES spectra with |b|6 10◦ and signal-to-noise ratio (S/N) > 50. Combined with the DIBs measured in GIBS spectra (Paper I), we confirmed a tight relation between EW and E(J −KS) as well as AV, with similar fitting coefficients to those found by previous works. With a more accurate sample and the consideration of the solar motion, the rest-frame wavelength of DIB λ8620 was redetermined as 8620.83 Å, with a mean fit error of 0.36 Å. We studied the kinematics of the DIB carriers by tracing their median radial velocities in each field in the local standard of rest (VLSR) and into the galactocentric frame (VGC), respectively, as a function of the Galactic longitudes. Based on the median VLSR and two Galactic rotation models, we obtained valid kinematic distances of the DIB carriers for nine GIBS and ten GES fields. We also found a linear relation between the DIB λ8620 measured in this work and the near-infrared DIB in APOGEE spectra at 1.5273μm, and we estimated the carrier abundance to be slightly lower compared to the DIB λ15273. Conclusions. We demonstrate that the DIB carriers can be located much closer to the observer than the background stars based on the following arguments: (i) qualitatively, the carriers occupy in the Galactic longitude–velocity diagram typical rotation velocities of stars in the local Galactic disk, while the background stars in the GIBS survey are mainly located in the Galactic bulge; (ii) quantitatively, all the derived kinematic distances of the DIB carriers are smaller than the median distances to background stars in each field. A linear correlation between DIB λ8620 and DIB λ15273 has been established, showing similar carrier abundances and making them both attractive for future studies of the interstellar environments.","PeriodicalId":785,"journal":{"name":"The Astronomy and Astrophysics Review","volume":"5 1","pages":""},"PeriodicalIF":25.8,"publicationDate":"2021-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76384997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Modelling the chemical evolution of the Milky Way","authors":"Francesca Matteucci","doi":"10.1007/s00159-021-00133-8","DOIUrl":"10.1007/s00159-021-00133-8","url":null,"abstract":"<div><p>In this review, I will discuss the comparison between model results and observational data for the Milky Way, the predictive power of such models as well as their limits. Such a comparison, known as Galactic archaeology, allows us to impose constraints on stellar nucleosynthesis and timescales of formation of the various Galactic components (halo, bulge, thick disk and thin disk).</p></div>","PeriodicalId":785,"journal":{"name":"The Astronomy and Astrophysics Review","volume":"29 1","pages":""},"PeriodicalIF":27.8,"publicationDate":"2021-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00159-021-00133-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138514252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Geometry of radio pulsar signals: The origin of pulsation modes and nulling","authors":"J. Dyks","doi":"10.1051/0004-6361/202141243","DOIUrl":"https://doi.org/10.1051/0004-6361/202141243","url":null,"abstract":"Radio pulsars exhibit an enormous diversity of single pulse behaviour that involves sudden changes in pulsation mode and nulling occurring on timescales of tens or hundreds of spin periods. The pulsations appear both chaotic and quasi-regular, which has hampered their interpretation for decades. Here I show that the pseudo-chaotic complexity of single pulses is caused by the viewing of a relatively simple radio beam that has a sector structure traceable to the magnetospheric charge distribution. The slow ExB drift of the sector beam, when sampled by the line of sight, produces the classical drift-period-folded patterns known from observations. The drifting azimuthal zones of the beam produce the changes in pulsation modes and both the intermodal and sporadic nulling at timescales of beating between the drift and the star spin. The axially symmetric conal beams are thus a superficial geometric illusion, and the standard carousel model of pulsar radio beams does not apply. The beam suggests a particle flow structure that involves inward motions with possible inward emission.","PeriodicalId":785,"journal":{"name":"The Astronomy and Astrophysics Review","volume":"5 1","pages":""},"PeriodicalIF":25.8,"publicationDate":"2021-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89629261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Erratum: Temporal evolution of small-scale internetwork magnetic fields in the solar photosphere (A&A (2021) 647 (A182) DOI: 10.1051/0004-6361/202040028)","authors":"R. J. Campbell, M. Mathioudakis, M. Collados, P. Keys, A. Ramos, C. Nelson, D. Kuridze, A. Reid","doi":"10.1051/0004-6361/202040028E","DOIUrl":"https://doi.org/10.1051/0004-6361/202040028E","url":null,"abstract":"We correct a typographical error in the original paper. Figures 10, 12, 14, 15, and 16 contain a table in the top right panel with four columns and four rows of values. The line of sight velocity, vLOS, values for scheme 1 inversions (in the fourth row, first column and second column) are inserted the wrong way around. The values themselves are correct, but printed in the wrong column. All other values in the tables remain unaffected, and none of the paper's discussions or conclusions are impacted. We provide corrected versions of Figs. 10, 12, 14, 15, and 16 in Figs. 1, 2, 3, 4, and 5, respectively.","PeriodicalId":785,"journal":{"name":"The Astronomy and Astrophysics Review","volume":"57 1","pages":""},"PeriodicalIF":25.8,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73266724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}