arXiv - PHYS - Atomic Physics最新文献

{"title":"Electromagnetically-Induced-Transparency Cooling with a Tripod Structure in a Hyperfine Trapped Ion with Mixed-Species Crystals","authors":"J. J. Wu, P. -Y. Hou, S. D. Erickson, A. D. Brandt, Y. Wan, G. Zarantonello, D. C. Cole, A. C. Wilson, D. H. Slichter, D. Leibfried","doi":"arxiv-2408.13407","DOIUrl":"https://doi.org/arxiv-2408.13407","url":null,"abstract":"Cooling of atomic motion is a crucial tool for many branches of atomic\u0000physics, ranging from fundamental physics explorations to quantum information\u0000and sensing. For trapped ions, electromagnetically-induced-transparency (EIT)\u0000cooling has received attention for the relative speed, low laser power\u0000requirements, and broad cooling bandwidth of the technique. However, in\u0000applications where the ion used for cooling has hyperfine structure to enable\u0000long coherence times, it is difficult to find a closed three-level system in\u0000which to perform standard EIT cooling. Here, we demonstrate successful EIT\u0000cooling on 25Mg+ by the addition of an extra laser frequency; this method can\u0000be applied to any ion with non-zero nuclear spin. Furthermore, we demonstrate\u0000simultaneous EIT cooling of all axial modes in mixed-species crystals 9Be+ -\u000025Mg+ and 9Be+ - 25Mg+ - 9Be+ through the 25Mg+ ion.","PeriodicalId":501039,"journal":{"name":"arXiv - PHYS - Atomic Physics","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142176400","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 triaxial vectorization technique for a single-beam zero-field atomic magnetometer to suppress cross-axis projection error","authors":"Rach Dawson, Marcin S. Mrozowski, Dominic Hunter, Carolyn O'Dwyer, Erling Riis, Paul. F. Griffin, Stuart Ingleby","doi":"arxiv-2408.12994","DOIUrl":"https://doi.org/arxiv-2408.12994","url":null,"abstract":"Zero-field optically pumped magnetometers (OPMs) have emerged as an important\u0000technology for biomagnetism due to their ulta-sensitive performance, contained\u0000within a non-cryogenic small-scale sensor-head. The compactness of such OPMs is\u0000often achieved through simplified detection schemes, which typically provide\u0000only single-axis magnetic field information. However, multi-axis static\u0000magnetic fields on non-measurement axes cause a systematic error that manifests\u0000as amplitude and phase errors across the measurement axis. Here we present a\u0000triaxial operational technique for a compact zero-field OPM which suppresses\u0000multi-axis systematic errors through simultaneous measurement and closed-loop\u0000active control of the static magnetic fields across all axes. The demonstrated\u0000technique requires magnetic modulation across two axes while providing static\u0000field information for all three axes. We demonstrate this technique on a\u0000rubidium laboratory-based zero-field magnetometer, achieving a bandwidth of 380\u0000Hz with sensitivities of $<25$ fT/$sqrt{rm{Hz}}$ across both transverse axes\u0000and $65$ fT/$sqrt{rm{Hz}}$ along the beam axis. Using the proposed triaxial\u0000technique, we demonstrate precise tracking of a 2 Hz triaxial vector test\u0000signal and suppression of systematic cross-axis projection errors over an\u0000extended period, $simeq20$~min.","PeriodicalId":501039,"journal":{"name":"arXiv - PHYS - Atomic Physics","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142176398","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 low-power microstructured atomic oven for alkaline-earth-like elements","authors":"Julian Pick, Julia Voß, Simon Hirt, Jens Kruse, Tobias Leopold, Roman Schwarz, Carsten Klempt","doi":"arxiv-2408.12471","DOIUrl":"https://doi.org/arxiv-2408.12471","url":null,"abstract":"Alkaline-earth-like elements play pivotal roles in advanced quantum sensing\u0000technologies, notably optical clocks, with unprecedented precision achieved in\u0000recent years. Despite remarkable progress, current optical lattice clocks still\u0000face challenges in meeting the demanding size, weight, and power consumption\u0000constraints essential for space applications. Conventional atom sources, such\u0000as ovens or dispensers, require substantial heating power, making up a\u0000significant fraction of the system's overall power consumption. Addressing this\u0000challenge, we present a novel microstructured atomic oven based on fused\u0000silica, designed for miniaturization and low-power operation. We characterize\u0000the oven by loading a magneto-optical trap with Yb evaporated from the oven and\u0000demonstrate operation with a loading rate above $10^8$\u0000$mathrm{atoms}/mathrm{s}$ for heating powers below $250$ $mathrm{mW}$.","PeriodicalId":501039,"journal":{"name":"arXiv - PHYS - Atomic Physics","volume":"141 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142176399","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 Setup to Study Atomic State Population Dynamics and Optical Polarization at CRYRING@ESR","authors":"K. MohrInstitut für Kernphysik, Technische Universität Darmstadt, GermanyHelmholtz Forschungsakademie Hessen für FAIR, R. SánchezGSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany, W. NörtershäuserInstitut für Kernphysik, Technische Universität Darmstadt, GermanyHelmholtz Forschungsakademie Hessen für FAIR, Z. AndelkovicGSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany, V. HannenInstitut für Kernphysik, Universität Münster, Germany, E. -O. HanuGSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany, F. HerfurthGSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany, R. HeßGSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany, M. HorstInstitut für Kernphysik, Technische Universität Darmstadt, GermanyHelmholtz Forschungsakademie Hessen für FAIR, P. ImgramInstitut für Kernphysik, Technische Universität Darmstadt, Germany, K. KönigInstitut für Kernphysik, Technische Universität Darmstadt, GermanyHelmholtz Forschungsakademie Hessen für FAIR, C. KrantzGSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany, M. LestinskyGSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany, Yu. A. LitvinovGSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, GermanyHelmholtz Forschungsakademie Hessen für FAIR, E. MenzGSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, GermanyInstitut für Kernphysik, Goethe Universität Frankfurt, Germany, P. MüllerInstitut für Kernphysik, Technische Universität Darmstadt, Germany, J. PalmesInstitut für Kernphysik, Technische Universität Darmstadt, Germany, S. RauschInstitut für Kernphysik, Technische Universität Darmstadt, GermanyHelmholtz Forschungsakademie Hessen für FAIR, T. RatajczykInstitut für Kernphysik, Technische Universität Darmstadt, Germany, L. RenthInstitut für Kernphysik, Technische Universität Darmstadt, Germany, J. RossbachGSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany, R. S. SidhuGSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany, F. SommerInstitut für Kernphysik, Technische Universität Darmstadt, Germany, J. SpahnInstitut für Kernphysik, Technische Universität Darmstadt, Germany, N. StallkampGSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, GermanyInstitut für Kernphysik, Goethe Universität Frankfurt, Germany, K. UeberholzInstitut für Kernphysik, Universität Münster, Germany, G. VorobjevGSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany, C. WeinheimerInstitut für Kernphysik, Universität Münster, Germany, D. ZisisInstitut für Kernphysik, Technische Universität Darmstadt, Germany","doi":"arxiv-2408.12368","DOIUrl":"https://doi.org/arxiv-2408.12368","url":null,"abstract":"We present a recently established setup for laser spectroscopy at CRYRING@ESR\u0000at the GSI Helmholtz Centre for Heavy Ion Research. Here, laser spectroscopy\u0000can be performed on stored and cooled ion bunches and coasting beams. First\u0000spectra of $^{24,25}$Mg$^+$ ions are presented that were recorded by classical\u0000Doppler-limited fluorescence spectroscopy as well as $Lambda$-spectroscopy\u0000using counter- and copropagating laser beams that are Doppler-shifted by\u0000several nm.","PeriodicalId":501039,"journal":{"name":"arXiv - PHYS - Atomic Physics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142176401","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":"Full non-LTE spectral line formation III. The case of a two-level atom with broadened upper level","authors":"M. Sampoorna, F. Paletou, V. Bommier, T. Lagache","doi":"arxiv-2408.12244","DOIUrl":"https://doi.org/arxiv-2408.12244","url":null,"abstract":"In the present paper we consider the full nonlocal thermodynamic equilibrium\u0000(non-LTE) radiation transfer problem. This formalism allows us to account for\u0000deviation from equilibrium distribution of both the radiation field and the\u0000massive particles. In the present study two-level atoms with broadened upper\u0000level represent the massive particles. In the absence of velocity-changing\u0000collisions, we demonstrate the analytic equivalence of the full non-LTE source\u0000function with the corresponding standard non-LTE partial frequency\u0000redistribution (PFR) model. We present an iterative method based on operator\u0000splitting techniques to numerically solve the problem at hand. We benchmark it\u0000against the standard non-LTE transfer problem for a two-level atom with PFR. We\u0000illustrate the deviation of the velocity distribution function of excited atoms\u0000from the equilibrium distribution. We also discuss the dependence of the\u0000emission profile and the velocity distribution function on elastic collisions\u0000and velocity-changing collisions.","PeriodicalId":501039,"journal":{"name":"arXiv - PHYS - Atomic Physics","volume":"151 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142176428","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":"High-accuracy Measurements of Core-excited Transitions in Light Li-like Ions","authors":"Moto Togawa, Steffen Kühn, Chintan Shah, Vladimir A. Zaystev, Natalia S. Oreshkina, Jens Buck, Sonja Bernitt, René Steinbrügge, Jörn Seltmann, Moritz Hoesch, Christoph H. Keitel, Thomas Pfeifer, Maurice A. Leutenegger, José R. Crespo López-Urrutia","doi":"arxiv-2408.12219","DOIUrl":"https://doi.org/arxiv-2408.12219","url":null,"abstract":"The transition energies of the two $1s$-core-excited soft X-ray lines (dubbed\u0000q and r) from $1s^2 2s ^1S_{1/2}$ to the respective upper levels\u0000$1s(^{2}S)2s2p(^{3}P) ^{2}P_{3/2}$ and $^{2}P_{1/2}$ of Li-like oxygen,\u0000fluorine and neon were measured and calibrated using several nearby transitions\u0000of He-like ions. The major remaining source of energy uncertainties in\u0000monochromators, the periodic fluctuations produced by imperfect angular encoder\u0000calibration, is addressed by a simultaneously running photoelectron\u0000spectroscopy measurement. This leads to an improved energy determination of 5\u0000parts per million, showing fair agreement with previous theories as well as\u0000with our own, involving a complete treatment of the autoionizing states studied\u0000here. Our experimental results translate to an uncertainty of only 1.6,km/s\u0000for the oxygen line qr-blend used to determine the outflow velocities of active\u0000galactic nuclei, ten times smaller than previously possible.","PeriodicalId":501039,"journal":{"name":"arXiv - PHYS - Atomic Physics","volume":"106 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142176427","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":"Hanle effect for lifetime determinations in the soft X-ray regime","authors":"Moto Togawa, Jan Richter, Chintan Shah, Marc Botz, Joshua Nenninger, Jonas Danisch, Joschka Goes, Steffen Kühn, Pedro Amaro, Awad Mohamed, Yuki Amano, Stefano Orlando, Roberta Totani, Monica de Simone, Stephan Fritzsche, Thomas Pfeifer, Marcello Coreno, Andrey Surzhykov, José R. Crespo López-Urrutia","doi":"arxiv-2408.12227","DOIUrl":"https://doi.org/arxiv-2408.12227","url":null,"abstract":"By exciting a series of $1mathrm{s}^{2}, ^{1}mathrm{S}_{0} to\u00001mathrm{s}nmathrm{p}, ^{1}mathrm{P}_{1}$ transitions in helium-like\u0000nitrogen ions with linearly polarized monochromatic soft X-rays at the Elettra\u0000facility, we found a change in the angular distribution of the fluorescence\u0000sensitive to the principal quantum number $n$. In particular it is observed\u0000that the ratio of emission in directions parallel and perpendicular to the\u0000polarization of incident radiation increases with higher $n$. We find this\u0000$n$-dependence to be a manifestation of the Hanle effect, which served as a\u0000practical tool for lifetime determinations of optical transitions since its\u0000discovery in 1924. In contrast to traditional Hanle effect experiments, in\u0000which one varies the magnetic field and considers a particular excited state,\u0000we demonstrate a 'soft X-ray Hanle effect' which arises in a static magnetic\u0000field but for a series of excited states. By comparing experimental data with\u0000theoretical predictions, we were able to determine lifetimes ranging from\u0000hundreds of femtoseconds to tens of picoseconds of the\u0000$1mathrm{s}nmathrm{p}, ^{1}mathrm{P}_{1}$ levels, which find excellent\u0000agreement with atomic-structure calculations. We argue that dedicated soft\u0000X-ray measurements could yield lifetime data that is beyond current\u0000experimental reach and cannot yet be predicted with sufficient accuracy.","PeriodicalId":501039,"journal":{"name":"arXiv - PHYS - Atomic Physics","volume":"34 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142176426","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":"Fine-structure changing collisions in $^{87}$Rb upon D2 excitation in the hyperfine Paschen-Back regime","authors":"Clare R. Higgins, Danielle Pizzey, Ifan G. Hughes","doi":"arxiv-2408.11689","DOIUrl":"https://doi.org/arxiv-2408.11689","url":null,"abstract":"We investigate fine structure changing collisions in $^{87}$Rb vapour upon D2\u0000excitation in a thermal vapour at 350 K; the atoms are placed in a 0.6 T axial\u0000magnetic field in order to gain access to the hyperfine Pashen-Back regime.\u0000Following optical excitation on the D2 line, the exothermic transfer\u00005P$_{3/2}$$rightarrow$5P$_{1/2}$ occurs as a consequence of buffer-gas\u0000collisions; the $^{87}$Rb subsequently emits a photon on the D1 transition. We\u0000employ single-photon counting apparatus to monitor the D1 fluorescence, with an\u0000etalon filter to provide high spectral resolution. By studying the D1\u0000fluorescence when the D2 excitation laser is scanned, we see that during the\u0000collisional transfer process the $m_{J}$ quantum number of the atom changes,\u0000but the nuclear spin projection quantum number, $m_{I}$, is conserved. A simple\u0000kinematic model incorporating a coefficient of restitution in the collision\u0000accounted for the change in velocity distribution of atoms undergoing\u0000collisions, and the resulting fluorescence lineshape. The experiment is\u0000conducted with a nominally ``buffer-gas free\" vapour cell; our results show\u0000that fine structure changing collisions are important with such media, and\u0000point out possible implications for quantum-optics experiments in thermal\u0000vapours producing entangled photon pairs with the double ladder configuration,\u0000and solar physics magneto-optical filters.","PeriodicalId":501039,"journal":{"name":"arXiv - PHYS - Atomic Physics","volume":"44 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142176436","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":"Observation of Asymmetric Sideband Generation in Strongly-driven Rydberg Atoms","authors":"Dangka Shylla, Nikunjkumar Prajapati, Andrew P. Rotunno, Noah Schlossberger, Dixith Manchaiah, William J. Watterson, Alexandra Artusio-Glimpse, Samuel Berweger, Matthew T. Simons, Christopher L. Holloway","doi":"arxiv-2408.10989","DOIUrl":"https://doi.org/arxiv-2408.10989","url":null,"abstract":"Improving the bandwidth of Rydberg atom-based receivers is an ongoing\u0000challenge owing to the long-lived Rydberg state lifetimes that limit the\u0000refresh rate of ground state atoms. In particular, the LO-based Rydberg mixer\u0000approach allows for bandwidths into the few-MHz range. Here, we use heterodyne\u0000detection of the Rydberg atom receiver probe laser to separate the negative and\u0000positive sidebands that originate from distinct six wave mixing processes, in\u0000order to investigate their individual bandwidths. We experimentally confirm the\u0000prediction that the negative sideband exhibits a higher bandwidth than the\u0000positive sideband. We further explore the effect of coupling and probe laser\u0000Rabi frequency on the bandwidth, which we find to be in good agreement with our\u0000model. We achieved a maximum experimental (and theoretical) bandwidth of about\u000011 (11) MHz and 3.5 (5) MHz for the negative and positive sidebands,\u0000respectively, from the -3dB roll-off point for optimized field parameters. This\u0000work provides insight into the bandwidth-limiting features of Rydberg atom\u0000receivers and points the way towards further optimization of their response.","PeriodicalId":501039,"journal":{"name":"arXiv - PHYS - Atomic Physics","volume":"36 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142176429","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":"Relativistic and Electron Correlation Effects in Static Dipole Polarizabilities for Main-Group Elements","authors":"YingXing Cheng","doi":"arxiv-2408.10513","DOIUrl":"https://doi.org/arxiv-2408.10513","url":null,"abstract":"In this study, I compute the static dipole polarizability of main-group\u0000elements using the finite-field method combined with relativistic\u0000coupled-cluster and configuration interaction simulations. The computational\u0000results closely align with the values recommended in the 2018 table of static\u0000dipole polarizabilities of neutral elements [Mol. Phys. 117, 1200 (2019)].\u0000Additionally, I investigate the influence of relativistic effects and electron\u0000correlation on atomic dipole polarizabilities. Specifically, three types of\u0000relativistic effects impacting dipole polarizabilities are studied:\u0000scalar-relativistic, spin-orbit coupling, and fully relativistic Dirac-Coulomb\u0000effects. The results indicate that scalar-relativistic effects are predominant\u0000for atoms in Groups 1--2, with minimal influence from spin-orbit coupling\u0000effects. Conversely, for elements in Groups 13--18, scalar-relativistic effects\u0000are less significant, while spin-orbit coupling significantly affects elements\u0000starting from the fourth row in Groups 13--14 and from the fifth row in Groups\u000015--18. In each category of relativistic effects, the impact of electron\u0000correlation is evaluated. The results show that electron correlation\u0000significantly influences dipole polarizability calculations, particularly for\u0000Groups 1--2 and 13--14 atoms, but is less significant for Groups 15--18 atoms.\u0000This study provides a comprehensive and consistent dataset of dipole\u0000polarizabilities and contributes to a systematic understanding of the roles of\u0000relativistic and electron correlation effects in atomic dipole\u0000polarizabilities, serving as a valuable reference for future research.","PeriodicalId":501039,"journal":{"name":"arXiv - PHYS - Atomic Physics","volume":"41 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142176430","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}