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2. Microlensig Binaries with Candidate Brown Dwarf Companions

Author

Shin, I. -G., Han, C., Gould, A., Udalski, A., Sumi, T., Dominik, M., Beaulieu, J. -P., Tsapras, Y., Bozza, V., Szymański, M. K., Kubiak, M., Soszyński, I., Pietrzyński, G., Poleski, R., Ulaczyk, K., Pietrukowicz, P., Kozłowski, S., Skowron, J., Wyrzykowski, Ł., Abe, F., Bennett, D. P., Bond, I. A., Botzler, C. S., Freeman, M., Fukui, A., Furusawa, K., Hayashi, F., Hearnshaw, J. B., Hosaka, S., Itow, Y., Kamiya, K., Kilmartin, P. M., Kobara, S., Korpela, A., Lin, W., Ling, C. H., Makita, S., Masuda, K., Matsubara, Y., Miyake, N., Muraki, Y., Nagaya, M., Nishimoto, K., Ohnishi, K., Okumura, T., Omori, K., Perrott, Y. C., Rattenbury, N., Saito, To., Skuljan, L., Sullivan, D. J., Suzuki, D., Sweatman, W. L., Tristram, P. J., Wada, K., Yock, P. C. M., Christie, G. W., Depoy, D. L., Dong, S., Gal-Yam, A., Gaudi, B. S., Hung, L. -W., Janczak, J., Kaspi, S., Maoz, D., McCormick, J., McGregor, D., Moorhouse, D., Muñoz, J. A., Natusch, T., Nelson, C., Pogge, R. W., Tan, T. -G., Polishook, D., Shvartzvald, Y., Shporer, A., Thornley, G., Malamud, U., Yee, J. C., Choi, J. -Y., Jung, Y. -K., Park, H., Lee, C. -U., Park, B. -G., Koo, J. -R., Bajek, D., Bramich, D. M., Browne, P., Horne, K., Ipatov, S., Snodgrass, C., Steele, I., Street, R., Alsubai, K. A., Burgdorf, M. J., Novati, S. Calchi, Dodds, P., Dreizler, S., Fang, X. -S., Grundahl, F., Gu, C. -H., Hardis, S., Harpsøe, K., Hinse, T. C., Hundertmark, M., Jessen-Hansen, J., Jørgensen, U. G., Kains, N., Kerins, E., Liebig, C., Lund, M., Lundkvist, M., Mancini, L., Mathiasen, M., Hornstrup, A., Penny, M. T., Proft, S., Rahvar, S., Ricci, D., Scarpetta, G., Skottfelt, J., Southworth, J., Surdej, J., Tregloan-Reed, J., Wertz, O., Zimmer, F., Albrow, M. D., Batista, V., Brillant, S., Caldwell, J. A. R., Calitz, J. J., Cassan, A., Cole, A., Cook, K. H., Corrales, E., Coutures, Ch., Dieters, S., Prester, D. Dominis, Donatowicz, J., Fouqué, P., Greenhill, J., Hill, K., Hoffman, M., Kane, S. R., Kubas, D., Marquette, J. -B., Martin, R., Meintjes, P., Menzies, J., Pollard, K. R., Sahu, K. C., Wambsganss, J., Williams, A., Vinter, C., and Zub, M.

Subjects
Astrophysics - Solar and Stellar Astrophysics
Abstract

Brown dwarfs are important objects because they may provide a missing link between stars and planets, two populations that have dramatically different formation history. In this paper, we present the candidate binaries with brown dwarf companions that are found by analyzing binary microlensing events discovered during 2004 - 2011 observation seasons. Based on the low mass ratio criterion of q < 0.2, we found 7 candidate events, including OGLE-2004-BLG-035, OGLE-2004-BLG-039, OGLE-2007-BLG-006, OGLE-2007-BLG-399/MOA-2007-BLG-334, MOA-2011-BLG-104/OGLE-2011-BLG-0172, MOA-2011-BLG-149, and MOA-201-BLG-278/OGLE-2011-BLG-012N. Among them, we are able to confirm that the companions of the lenses of MOA-2011-BLG-104/OGLE-2011-BLG-0172 and MOA-2011-BLG-149 are brown dwarfs by determining the mass of the lens based on the simultaneous measurement of the Einstein radius and the lens parallax. The measured mass of the brown dwarf companions are (0.02 +/- 0.01) M_Sun and (0.019 +/- 0.002) M_Sun for MOA-2011-BLG-104/OGLE-2011-BLG-0172 and MOA-2011-BLG-149, respectively, and both companions are orbiting low mass M dwarf host stars. More microlensing brown dwarfs are expected to be detected as the number of lensing events with well covered light curves increases with new generation searches., Comment: 10 pages, 9 figures, 4 tables

Published
2012
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3. Characterizing Lenses and Lensed Stars of High-Magnification Single-lens Gravitational Microlensing Events With Lenses Passing Over Source Stars

Author

Choi, J. -Y., Shin, I. -G., Park, S. -Y., Han, C., Gould, A., Sumi, T., Udalski, A., Beaulieu, J. -P., Street, R., Dominik, M., Allen, W., Almeida, L. A., Bos, M., Christie, G. W., Depoy, D. L., Dong, S., Drummond, J., Gal-Yam, A., Gaudi, B. S., Henderson, C. B., Hung, L. -W., Jablonski, F., Janczak, J., Lee, C. -U., Mallia, F., Maury, A., McCormick, J., McGregor, D., Monard, L. A. G., Moorhouse, D., Muñoz, J. A., Natusch, T., Nelson, C., Park, B. -G., Pogge, R. W., Tan, T. -G. "TG", Thornley, G., Yee, J. C., Abe, F., Barnard, E., Baudry, J., Bennett, D. P., Bond, I. A., Botzler, C. S., Freeman, M., Fukui, A., Furusawa, K., Hayashi, F., Hearnshaw, J. B., Hosaka, S., Itow, Y., Kamiya, K., Kilmartin, P. M., Kobara, S., Korpela, A., Lin, W., Ling, C. H., Makita, S., Masuda, K., Matsubara, Y., Miyake, N., Muraki, Y., Nagaya, M., Nishimoto, K., Ohnishi, K., Okumura, T., Omori, K., Perrott, Y. C., Rattenbury, N., Saito, To., Skuljan, L., Sullivan, D. J., Suzuki, D., Suzuki, K., Sweatman, W. L., Takino, S., Tristram, P. J., Wada, K., Yock, P. C. M., Szymański, M. K., Kubiak, M., Pietrzyński, G., Soszyński, I., Poleski, R., Ulaczyk, K., Wyrzykowski, Ł., Kozłowski, S., Pietrukowicz, P., Albrow, M. D., Bachelet, E., Batista, V., Bennett, C. S., Bowens-Rubin, R., Brillant, S., Cassan, A., Cole, A., Corrales, E., Coutures, Ch., Dieters, S., Prester, D. Dominis, Donatowicz, J., Fouqué, P., Greenhill, J., Kane, S. R., Menzies, J., Sahu, K. C., Wambsganss, J., Williams, A., Zub, M., Allan, A., Bramich, D. M., Browne, P., Clay, N., Fraser, S., Horne, K., Kains, N., Mottram, C., Snodgrass, C., Steele, I., Tsapras, Y., Alsubai, K. A., Bozza, V., Burgdorf, M. J., Novati, S. Calchi, Dodds, P., Dreizler, S., Finet, F., Gerner, T., Glitrup, M., Grundahl, F., Hardis, S., Harpsøe, K., Hinse, T. C., Hundertmark, M., Jørgensen, U. G., Kerins, E., Liebig, C., Maier, G., Mancini, L., Mathiasen, M., Penny, M. T., Proft, S., Rahvar, S., Ricci, D., Scarpetta, G., Schäfer, S., Schönebeck, F., Skottfelt, J., Surdej, J., Southworth, J., and Zimmer, F.

Subjects
Astrophysics - Solar and Stellar Astrophysics
Abstract

We present the analysis of the light curves of 9 high-magnification single-lens gravitational microlensing events with lenses passing over source stars, including OGLE-2004-BLG-254, MOA-2007-BLG-176, MOA-2007-BLG-233/OGLE-2007-BLG-302, MOA-2009-BLG-174, MOA-2010-BLG-436, MOA-2011-BLG-093, MOA-2011-BLG-274, OGLE-2011-BLG-0990/MOA-2011-BLG-300, and OGLE-2011-BLG-1101/MOA-2011-BLG-325. For all events, we measure the linear limb-darkening coefficients of the surface brightness profile of source stars by measuring the deviation of the light curves near the peak affected by the finite-source effect. For 7 events, we measure the Einstein radii and the lens-source relative proper motions. Among them, 5 events are found to have Einstein radii less than 0.2 mas, making the lenses candidates of very low-mass stars or brown dwarfs. For MOA-2011-BLG-274, especially, the small Einstein radius of $\theta_{\rm E}\sim 0.08$ mas combined with the short time scale of $t_{\rm E}\sim 2.7$ days suggests the possibility that the lens is a free-floating planet. For MOA-2009-BLG-174, we measure the lens parallax and thus uniquely determine the physical parameters of the lens. We also find that the measured lens mass of $\sim 0.84\ M_\odot$ is consistent with that of a star blended with the source, suggesting that the blend is likely to be the lens. Although we find planetary signals for none of events, we provide exclusion diagrams showing the confidence levels excluding the existence of a planet as a function of the separation and mass ratio., Comment: 14 pages, 12 figures, 5 tables

Published
2011
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4. Microlensing Binaries Discovered through High-Magnification Channel

Author

Shin, I. -G., Choi, J. -Y., Park, S. -Y., Han, C., Gould, A., Sumi, T., Udalski, A., Beaulieu, J. -P., Dominik, M., Allen, W., Bos, M., Christie, G. W., Depoy, D. L., Dong, S., Drummond, J., Gal-Yam, A., Gaudi, B. S., Hung, L. -W., Janczak, J., Kaspi, S., Lee, C. -U., Mallia, F., Maoz, D., Maury, A., McCormick, J., Monard, L. A. G., Moorhouse, D., Muñoz, J. A., Natusch, T., Nelson, C., Park, B. -G., Pogge, R. W., Polishook, D., Shvartzvald, Y., Shporer, A., Thornley, G., Yee, J. C., Abe, F., Bennett, D. P., Bond, I. A., Botzler, C. S., Fukui, A., Furusawa, K., Hayashi, F., Hearnshaw, J. B., Hosaka, S., Itow, Y., Kamiya, K., Kilmartin, P. M., Kobara, S., Korpela, A., Lin, W., Ling, C. H., Makita, S., Masuda, K., Matsubara, Y., Miyake, N., Muraki, Y., Nagaya, M., Nishimoto, K., Ohnishi, K., Okumura, T., Omori, K., Perrott, Y. C., Rattenbury, N., Saito, To., Skuljan, L., Sullivan, D. J., Suzuki, D., Sweatman, W. L., Tristram, P. J., Wada, K., Yock, P. C. M., Szymański, M. K., Kubiak, M., Pietrzyński, G., Soszyński, I., Poleski, R., Ulaczyk, K., Wyrzykowski, Ł., Kozłowski, S., Pietrukowicz, P., Albrow, M. D., Batista, V., Bramich, D. M., Brillant, S., Caldwell, J. A. R., Calitz, J. J., Cassan, A., Cole, A., Cook, K. H., Corrales, E., Coutures, Ch., Dieters, S., Prester, D. Dominis, Donatowicz, J., Fouqué, P., Greenhill, J., Hoffman, M., Jørgensen, U. G., Kane, S. R., Kubas, D., Marquette, J. -B., Martin, R., Meintjes, P., Menzies, J., Pollard, K. R., Sahu, K. C., Wambsganss, J., Williams, A., Vinter, C., Zub, M., Allan, A., Browne, P., Horne, K., Snodgrass, C., Steele, I., Street, R., Tsapras, Y., Alsubai, K. A., Bozza, V., Burgdorf, M. J., Novati, S. Calchi, Dodds, P., Dreizler, S., Finet, F., Gerner, T., Glitrup, M., Grundahl, F., Hardis, S., Harpsøe, K., Hessman, F. V., Hinse, T. C., Hundertmark, M., Kains, N., Kerins, E., Liebig, C., Maier, G., Mancini, L., Mathiasen, M., Penny, M. T., Proft, S., Rahvar, S., Ricci, D., Scarpetta, G., Schäfer, S., Schönebeck, F., Skottfelt, J., Surdej, J., Southworth, J., and Zimmer, F.

Subjects
Astrophysics - Solar and Stellar Astrophysics
Abstract

Microlensing can provide a useful tool to probe binary distributions down to low-mass limits of binary companions. In this paper, we analyze the light curves of 8 binary lensing events detected through the channel of high-magnification events during the seasons from 2007 to 2010. The perturbations, which are confined near the peak of the light curves, can be easily distinguished from the central perturbations caused by planets. However, the degeneracy between close and wide binary solutions cannot be resolved with a $3\sigma$ confidence level for 3 events, implying that the degeneracy would be an important obstacle in studying binary distributions. The dependence of the degeneracy on the lensing parameters is consistent with a theoretic prediction that the degeneracy becomes severe as the binary separation and the mass ratio deviate from the values of resonant caustics. The measured mass ratio of the event OGLE-2008-BLG-510/MOA-2008-BLG-369 is $q\sim 0.1$, making the companion of the lens a strong brown-dwarf candidate., Comment: 10 figures, 6 tables, 26 pages

Published
2011
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5. 1 um Excess Sources in the UKIDSS - I. Three T Dwarfs in the SDSS Southern Equatorial Stripe

Author

Matsuoka, Y., Peterson, B. A., Murata, K. L., Fujiwara, M., Nagayama, T., Suenaga, T., Furusawa, K., Miyake, N., Omori, K., Suzuki, D., and Wada, K.

Subjects
Astrophysics - Astrophysics of Galaxies, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

We report the discovery of two field brown dwarfs, ULAS J0128-0041 and ULAS J0321+0051, and the rediscovery of ULAS J0226+0051 (IfA 0230-Z1), in the Sloan Digital Sky Survey (SDSS) southern equatorial stripe. They are found in the course of our follow-up observation program of 1 um excess sources in the United Kingdom Infrared Telescope Infrared Deep Sky Survey. The Gemini Multi-Object Spectrographs spectra at red optical wavelengths (6500-10500 A) are presented, which reveal that they are early-T dwarfs. The classification is also supported by their optical to near-infrared colors. It is noted that ULAS J0321+0051 is one of the faintest currently known T dwarfs. The estimated distances to the three objects are 50-110 pc, thus they are among the most distant field T dwarfs known. Dense temporal coverage of the target fields achieved by the SDSS-II Supernova Survey allows us to perform a simple time-series analysis, which leads to the finding of significant proper motions of 150-290 mas/yr or the transverse velocities of 40-100 km/s for ULAS J0128-0041 and ULAS J0226+0051. We also find that there are no detectable, long-term (a-few-year) brightness variations above a few times 0.1 mag for the two brown dwarfs., Comment: Accepted for publication in the Astronomical Journal; Typos corrected

Published
2011
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6. Magnetic-susceptibility and specific-heat studies on the inhomogeneity of superconductivity in the underdoped La_2-x_Sr_x_CuO_4_

Author

Adachi, T., Omori, K., Tanabe, Y., and Koike, Y.

Subjects
Condensed Matter - Superconductivity, Condensed Matter - Strongly Correlated Electrons
Abstract

The possible inhomogeneity of superconductivity has been investigated by means of bulk-sensitive probes, using La_2-x_Sr_x_CuO_4_ (LSCO) single crystals from the underdoped to optimally doped regime. Measurements of the magnetic susceptibility, chi, on field cooling and specific heat have revealed that both the absolute value of chi at 2 K, regarded as corresponding to the superconducting (SC) volume fraction in a sample, and the Sommerfeld constant, reflecting the density of states of quasiparticles at the Fermi level, exhibit significant dependence on x, namely, on the hole concentration. This is the first experimental work strongly suggesting that a phase separation into SC and normal-state regions takes place in the underodped regime of LSCO as well as in the overdoped regime., Comment: 7 pages, 4 figures, the version 2 has been accepted for publication in J. Phys. Soc. Jpn

Published
2009
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7. Cu-spin dynamics in the overdoped regime of La_2-x_Sr_x_Cu_1-y_Zn_y_O_4_ probed by muon spin relaxation

Author

Risdiana, Adachi, T., Oki, N., Yairi, S., Tanabe, Y., Omori, K., Koike, Y., Suzuki, T., Watanabe, I., Koda, A., and Higemoto, W.

Subjects
Condensed Matter - Superconductivity, Condensed Matter - Strongly Correlated Electrons
Abstract

Muon-spin-relaxation measurements have been performed for the partially Zn-substituted La_2-x_Sr_x_Cu_1-y_Zn_y_O_4_ with y=0-0.10 in the overdoped regime up to x=0.30. In the 3 % Zn-substituted samples up to x=0.27, exponential-like depolarization of muon spins has been observed at low temperatures, indicating Zn-induced slowing-down of the Cu-spin fluctuations. The depolarization rate decreases with increasing x and almost no fast depolarization of muon spins has been observed for x=0.30 where superconductivity disappears. The present results suggest that the dynamical stripe correlations exist in the whole superconducting regime of La_2-x_Sr_x_CuO_4_ and that there is no quantum critical point at x~0.19., Comment: 6 pages, 5 figures

Published
2007
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8. Magnetic-field effects on the charge-spin stripe order in La-214 high-Tc cuprates

Author

Adachi, T., Omori, K., Kawamata, T., Kudo, K., Sasaki, T., Kobayashi, N., and Koike, Y.

Subjects
Condensed Matter - Superconductivity, Condensed Matter - Strongly Correlated Electrons
Abstract

Magnetic-field effects on the charge-spin stripe order in La-214 high-Tc cuprates have been investigated from measurements of the in-plane electrical-resistivity, Rho_ab_. In La_2-x_Ba_x_CuO_4_ with x=0.10 and La_2-x_Sr_x_CuO_4_ with x=0.115 where the incommensurate charge peaks are weak and unobservable in zero field in elastic neutron-scattering measurements, respectively, the normal-state value of Rho_ab_ at low temperatures markedly increases with increasing field up to 27 T. For La_2-x_Ba_x_CuO_4_ with x=0.11 and Zn-substituted La_2-x_Sr_x_Cu_1-y_Zn_y_O_4_ with x=0.115 and y=0.02 where the charge stripe order is fairly stabilized in zero field, on the other hand, the increase in Rho_ab_ with increasing field is negligibly small. In conclusion, when the charge-spin stripe order is not fully stable in zero field, magnetic field operates to stabilize the charge-spin stripe order. The value of Rho_ab_ increases with increasing field depending on the stability of the charge stripe order., Comment: 4 pages, 2 figures, Proceedings of Yamada Conference LX on Research in High Magnetic Fields (RHMF2006) (Satellite of ICM2006)

Published
2006
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16. Airway Stenosis : Forming a Disease Registry

Author

Kawai, Y., primary, Mizuno, K., additional, Kishimoto, Y., additional, Hirabayashi, H., additional, Furukawa, K., additional, Morimoto, N., additional, Maeda, K., additional, Kaneko, K., additional, and Omori, K., additional

Published
2023
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18. 42P Antitumor activity of zolbetuximab combined with chemotherapy and anti-mouse PD-1 antibody (anti-mPD-1) in a syngeneic mouse model and a virtual preclinical trial using a quantitative systems pharmacology (QSP) model

Author

Nakayama, T., primary, Oishi, M., additional, Weng, J., additional, Omori, K., additional, Kwon, C., additional, Nakazawa, T., additional, Nishibata, T., additional, Kinugasa, F., additional, Yoshida, T., additional, and Nagasaka, Y., additional

Published
2022
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27. Epigenetic landscape of supporting cell reprogramming toward hair cell regeneration in chick auditory epithelia.

Author

Nakagawa, T., Matsunaga, M., Takeuchi, M., Omori, K., and Iida, K.

Subjects
EPITHELIAL cells, EPIGENOMICS, POULTRY, CONFERENCES & conventions, REGENERATION (Biology), HAIR cells
Abstract

Sensorineural hearing loss is usually intractable because of virtually no capacity for hair cell (HC) regeneration in mammals. In contrast to mammals, lower vertebrates including birds have the capability for HC regeneration. Elucidation of precise mechanisms for HC regeneration in avian auditory epithelia will contribute to exploring key molecules for inducing HC regeneration in mammals. We previously established an explant culture model of the chick auditory epithelium, namely basilar papilla (BP), showing total HC loss and consecutive HC regeneration through direct conversion of supporting cells (SCs) to HCs (Matsunaga, 2020). Single-cell RNA sequencing using this model illustrated dynamic changes in expressed genes in BP SCs during direct conversion, which indicates that reprogramming of SCs to the precursor state occurs before differentiation into HCs (Matsunaga, 2023). To explore mechanisms of SC reprogramming toward hair cell regeneration in chick BP, we performed an integrated analysis of RNA- and ATAC-seq of chick BP explant cultures during the early phase (three time points) of HC regeneration. ATAC sequencing detected 80,366 peaks. Based on the distance from the transcription start site, and correlations between read counts and peak depths and between their alterations in a time course, we determined enhancer candidate loci for differentially expressed genes. We focused on a set of temporally upregulated genes during SC reprogramming in our previous single-cell RNA sequencing data (Matsunaga, 2023). In temporally upregulated genes during SC reprogramming, enhancer candidate loci were identified in nine genes. Motif enrichment analysis of these loci indicated transcription factors that may control chromatin remodeling in SC reprogramming. In the near future, we will examine spaciotemporal expression patterns of these transcription factors in regenerating chick BP. [ABSTRACT FROM AUTHOR]

Published
2024

36. Comparison between helium plasma induced surface structures in group 5 (Nb, Ta) and group 6 elements (Mo, W).

Author

Omori, K., Ito, A. M., Shiga, K., Yamashita, N., Ibano, K., Lee, H. T., and Ueda, Y.

Subjects
*NIOBIUM, *TANTALUM, *MOLYBDENUM, *TUNGSTEN, *HELIUM plasmas
Abstract

Group 5 elements (niobium and tantalum) and group 6 elements (molybdenum and tungsten) were exposed to helium plasma, and the resulting surface structures were observed by electron microscopy. Group 5 elements showed hole structures, where the size of the holes ranged from several tens of nm to a few hundred nm in diameter, while group 6 elements showed fiber-like structures. As a first step in understanding such differences, the difference in helium agglomeration energies and changes in the stress tensor as a function of the number of He atoms at interstitial sites were investigated for each element using density functional theory. The calculations revealed that helium atoms prefer to agglomerate in both of these groups. However, helium in group 6 elements can agglomerate more easily than group 5 elements due to higher binding energy. These results indicate a possible correlation between the shape of helium plasma induced surface nanostructures and the atomic level properties due to helium agglomeration. [ABSTRACT FROM AUTHOR]

Published
2017
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48. Fluctuations of various order parameters in cuprate and fe-based superconductors as revealed by microwave absorption measurements

Author

Gimazov, I. I., Talanov, Y. I., Adachi, T., Noji, T., Koike, Y., Omori, K., Tanabe, Y., Chareev, D., Vasiliev, A., Gimazov, I. I., Talanov, Y. I., Adachi, T., Noji, T., Koike, Y., Omori, K., Tanabe, Y., Chareev, D., and Vasiliev, A.

Abstract

Fluctuations of various order parameters are considered as the significant components of understanding the mechanism of high-Tc superconductivity. To study these fluctuations in the cuprate and Fe-based superconductors we use the joint measurements of direct current resistivity and non-resonant microwave absorption. Comparing data obtained with both methods allowed us to extract the contribution of dynamic charge density waves in La2−xSrxCuO4, superconducting fluctuations in Bi2Sr2Ca1−xYxCu2O8 and nematic fluctuations in FeTe1−xSex. © Kazan Federal University (KFU).

Published
2019

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