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Organic composts as A vehicle for the entry of microplastics into the environment: A comprehensive review

The science of the total environment 2023年 892卷 164758页

作者： Van-Re Le Minh-Ky Nguyen Hoang-Lam Nguyen Chitsan Lin Md Refat Jahan Rakib Van-Anh Thai Van-Giang Le Guilherme Malafaia Abubakr M Idris Ho Chi Minh City University of Food Industry (HUFI) 140 Le Trong Tan Street Tan Phu District Ho Chi Minh City 700000 Viet Nam. Faculty of Environment and Natural Resources Nong Lam University of Ho Chi Minh City Hamlet 6 Linh Trung Ward Thu Duc City Ho Chi Minh City 700000 Viet Nam Ph.D. Program in Maritime Science and Technology National Kaohsiung University of Science and Technology Kaohsiung 81157 Taiwan. Electronic address: nmky@hcmuaf.edu.vn. Department of Civil Engineering McGill University Montreal Canada. Ph.D. Program in Maritime Science and Technology National Kaohsiung University of Science and Technology Kaohsiung 81157 Taiwan Department of Marine Environmental Engineering National Kaohsiung University of Science and Technology Kaohsiung 81157 Taiwan. Department of Fisheries and Marine Science Faculty of Science Noakhali Science and Technology University Noakhali 3814 Bangladesh. Electronic address: rifatjahanrakib@***. Institute of Aquatic Science and Technology National Kaohsiung University of Science and Technology Kaohsiung City 81157 Taiwan. Central Institute for Natural Resources and Environmental Studies Vietnam National University Hanoi 111000 Viet Nam. Post-Graduation Program in Ecology Conservation and Biodiversity Federal University of Uberlândia Uberlândia MG Brazil Post-Graduation Program in Biotechnology and Biodiversity Federal University of Goiás Goiânia GO Brazil Post-Graduation Program in Conservation of Cerrado Natural Resources Goiano Federal Institute Urutaí GO Brazil. Electronic address: guilhermeifgoiano@***. Department of Chemistry College of Science King Khalid University 61431 Abha Saudi Arabia Research Center for Advanced Materials Science (RCAMS) King Khalid University Abha 61421 Saudi Arabia.

Plastic pollution is a widespread issue that poses a threat to agroecosystems. Recent data on microplastic (MP) pollution from compost and its application to soil have highlighted the potential impact of micropollutants that may be transferred from compost. Thus, we aim with this review to elucidate the distribution-occurrence, characterization, fate/transport, and potential risk of MPs from organic compost to gain comprehensive knowledge and mitigate the adverse impacts of compost application. The concentration of MPs in compost was up to thousands of items/kg. Among micropollutants, fibers, fragments, and films are the most common, with small MPs having a higher potential to absorb other pollutants and cause harm to organisms. Various synthetic polymers, including polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polystyrene (PS), polyvinyl chloride (PVC), polyester (PES), and acrylic polymers (AP), have been widely used of plastic items. MPs are emerging pollutants that can have diverse effects on soil ecosystems, as they can transfer potential pollutants from MPs to compost and then to the soil. Following the microbial degradation scheme, the transfer chain from plastics to compost to soil can be broken down into main stages, i.e., colonization - (bio)fragmentation - assimilation - and mineralization. Microorganisms and adding biochar play an essential role during composting, which can be an effective solution to enhance MP degradation. Findings have shown that stimulating free radical generation could promote the biodegradation efficacy of MPs and possibly remove their occurrence in compost, thereby reducing their contribution to ecosystem pollution. Furthermore, future recommendations were discussed to reduce ecosystem risks and health challenges.

关键词： Emerging contaminants Free radicals Mineralization Organic waste Plastic pollution Polymers

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Blood absorption improvement of a naturally derived hemostatic agent by atmospheric pressure plasma jet

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materials Today: Proceedings 2019年 17卷 2088-2096页

作者： Jureeporn Jaifu Kittiya Thunsiri Suruk Udomsom Dheerawan Boonyawan Wassanai Wattanutchariya Biomedical engineering program Faculty of Engineering Chiang Mai University Chaing Mai Thailand Biomedical engineering center(BMEC) Chiang Mai University Chiang Mai 50200 Thailand Advanced manufacturing technology research center(AMTech) Department of Industrial Engineering Chiang Mai University Chiang Mai Thailand Plasma and beam physics research facility(PBP) Department of Physics and Materials Faculty of Science Chiang Mai University Chiang Mai Thailand

Hemostatic capability improvement of a chitosan hemostatic agent was achieved by surface modification using the atmospheric pressure plasma jet experiment. The chitosan hemostatic agent acquired high blood absorption rate, at 4.60 ml/m, when exposed to input power 10 W of the radiofrequency power supply, the argon flow rate of 4 L/m mixture with an oxygen gas of 10 ml/m, and treatment time of 30 s. A significant decreased was observed in the hemoglobin leak value, inducing early blood clotting ability of clotting in 30 s. The strong relation of gas plasma discharge with the OH radical and the atomic oxygen, exhibited an increase in the hydrophilic properties, which lead to the chitosan hemostatic agent being very effective.

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Posture adjustment according to load inclination for a passive-type assistive wheelchair 1

Posture adjustment according to load inclination for a passi...

引用

1st IEEE International Conference on Industrial Cyber-Physical Systems, ICPS 2018

作者： Kohara, Ryo Iwaki, Masahiro Chugo, Daisuke Muramatsu, Satoshi Yokota, Sho Hashimoto, Hiroshi School of Science and Technology Kwansei Gakuin University Sanda Japan School of Information Science and Technology Tokai University Hiratsuka Kanagawa Japan Faculty of Science and Engineering Toyo University Kawagoe Saitama Japan Master Program of Innovation for Design and Engineering Advanced Institute of Industrial Technology Shinagawa Tokyo Japan

ISBN: (纸本)9781538665312

Considering the road inclination conditions, we proposed an upper body posture adjustment system for a passive-type assistive wheelchair. On an inclined road, there is a high probability that a wheelchair will move in a direction that is different from that desired by its user. In our previous research, we proposed a system that estimated a wheelchair user's intentions and worked passively to complement their intentional force. This was accomplished by negating the wheel traction that was generated by the road's inclination using only the servo brakes on each wheel. However, in some cases, our system failed to assist the driving motion of the user because it negated only the gravitational force. Therefore, our wheelchair succeeded in avoiding the unintended movement, but its user was required to row the hand rims with a considerable amount of force to overcome these braking forces. Consequently, we proposed an upper body posture adjustment system that adapts to the inclined road conditions and reduces the wheel traction that is generated by gravity. The proposed system inclined the wheelchair seat and aligned the upper body posture of its user to the center position of the wheelchair. Using this method, the proposed system maintained the position of the user's center of gravity with respect to the center position of the wheelchair. Our experimental findings suggested that the proposed passive-type assistive wheelchair can complement the user's intentional force with smaller brake tractions, indicating that the user can drive the wheelchair using less physical strength. © 2018 IEEE.

关键词： Wheelchairs

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Mechanism of Optical Rotation of Amino Acids Using Electronic State Calculation

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IOP Conference Series: materials science and engineering 2020年第1期835卷

作者： Shuichi Katsumoto Manami Mimura Tomohiko Ishii Genta Sakane Kazuyoshi Ogasawara Program of Advanced Materials Science Department of Engineering and Design Faculty of Engineering and Design Kagawa University 2217-20 Hayashi-cho Takamatsu Kagawa 761-0396 JAPAN. Department of Chemistry Faculty of Science Okayama University of Science 1-1 Ridaicho Kita-ku Okayama 700-0005 JAPAN. School of Science and Technology Kwansei Gakuin University 2-1 Gakuen Sanda Hyogo 669-1337 JAPAN.

Because of the chiral nature of the building blocks of living matter, an optical phenomena associated with the chirality constitute an important topic in physical chemistry. The specific optical rotation, which is a parameter for the characterization of the natural optical activity, depends strongly on the conformation of the molecule. In this study, we investigated the dependence of the optical rotation on a molecular conformation in the gas phase by calculating the electronic states of seven kind of chiral amino acids using the DV-Xα method. As a result, we can confirm the existence of an antibonding orbital on the side chain and the optical rotations are strongly related.

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The ALCHEMI atlas: principal component analysis reveals starburst evolution in NGC 253

arXiv

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arXiv 2024年

作者： Harada, Nanase Meier, David S. Martín, Sergio Muller, Sebastien Sakamoto, Kazushi Saito, Toshiki Gorski, Mark D. Henkel, Christian Tanaka, Kunihiko Mangum, Jeffrey G. Aalto, Susanne Aladro, Rebeca Bouvier, Mathilde Colzi, Laura Emig, Kimberly L. Herrero-Illana, Rubén Huang, Ko-Yun Kohno, Kotaro König, Sabine Nakanishi, Kouichiro Nishimura, Yuri Takano, Shuro Rivilla, Víctor M. Viti, Serena Watanabe, Yoshimasa van der Werf, Paul P. Yoshimura, Yuki National Astronomical Observatory of Japan 2-21-1 Osawa Mitaka Tokyo181-8588 Japan Institute of Astronomy and Astrophysics Academia Sinica 11F of AS/NTU Astronomy-Mathematics Building No.1 Sec. 4 Roosevelt Rd Taipei10617 Taiwan Astronomical Science Program Graduate Institute for Advanced Studies SOKENDAI 2-21-1 Osawa Mitaka Tokyo181-1855 Japan New Mexico Institute of Mining and Technology 801 Leroy Place SocorroNM87801 United States National Radio Astronomy Observatory PO Box O 1003 Lopezville Road SocorroNM87801 United States European Southern Observatory Alonso de Córdova 3107 Vitacura Santiago763-0355 Chile Joint ALMA Observatory Alonso de Córdova 3107 Vitacura Santiago763-0355 Chile Department of Space Earth and Environment Chalmers University of Technology Onsala Space Observatory OnsalaSE-439 92 Sweden Department of Physics and Astronomy Northwestern University EvanstonIL60208 United States Max-Planck-Institut für Radioastronomie Auf dem Hügel 69 Bonn53121 Germany Astronomy Department Faculty of Science King Abdulaziz University P. O. Box 80203 Jeddah21589 Saudi Arabia Department of Physics Faculty of Science and Technology Keio University 3-14-1 Hiyoshi Kanagawa Yokohama223-8522 Japan National Radio Astronomy Observatory 520 Edgemont Road CharlottesvilleVA22903-2475 United States Department of Space Earth and Environment Chalmers University of Technology GöteborgSE-412 96 Sweden Leiden Observatory Leiden University P.O. Box 9513 Leiden2300 RA Netherlands CSIC-INTA Ctra. de Ajalvir Km. 4 Torrejón de Ardoz Madrid28850 Spain Campus UAB Carrer de Magrans BarcelonaE-08193 Spain Institute of Astronomy Graduate School of Science The University of Tokyo 2-21-1 Osawa Mitaka Tokyo181-0015 Japan Department of Astronomy The University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo113-0033 Japan ALMA Project National Astronomical Observatory of Japan 2-21-1 Osawa Mitaka Tokyo181-8588 Japan Department of Physic

Molecular lines are powerful diagnostics of the physical and chemical properties of the interstellar medium (ISM). These ISM properties, which affect future star formation, are expected to differ in starburst galaxies from those of more quiescent galaxies. We investigate the ISM properties in the central molecular zone of the nearby starburst galaxy NGC 253 using the ultra-wide millimeter spectral scan survey from the ALMA Large program ALCHEMI. We present an atlas of velocity-integrated images at a 1′′. 6 resolution of 148 unblended transitions from 44 species, including the first extragalactic detection of HCNH+ and the first interferometric images of C3H+, NO, HCS+. We conduct a principal component analysis (PCA) on these images to extract correlated chemical species and to identify key groups of diagnostic transitions. To the best of our knowledge, our dataset is currently the largest astronomical set of molecular lines to which PCA has been applied. The PCA can categorize transitions coming from different physical components in NGC 253 such as i) young starburst tracers characterized by high-excitation transitions of HC3N and complex organic molecules (COMs) versus tracers of on-going star formation (radio recombination lines) and high-excitation transitions of CCH and CN tracing PDRs, ii) tracers of cloud-collision-induced shocks (low-excitation transitions of CH3OH, HNCO, HOCO+, and OCS) versus shocks from star-formation-induced outflows (high-excitation transitions of SiO), as well as iii) outflows showing emission from HOC+, CCH, H3O+, CO isotopologues, HCN, HCO+, CS, and CN. Our findings show these intensities vary with galactic dynamics, star formation activities, and stellar feedback. © 2024, CC BY.

关键词： Principal component analysis

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Disorder-driven glasslike thermal conductivity in colusite Cu26V2Sn6S32 investigated by Mössbauer spectroscopy and inelastic neutron scattering

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Physical Review materials 2020年第2期4卷 025404-025404页

作者： Christophe Candolfi Gabin Guélou Cédric Bourgès Andrew R. Supka Rabih Al Rahal Al Orabi Marco Fornari Bernard Malaman Gérard Le Caër Pierric Lemoine Vincent Hardy Jean-Marc Zanotti Raju Chetty Michihiro Ohta Koichiro Suekuni Emmanuel Guilmeau Institut Jean Lamour UMR 7198 CNRS – Université de Lorraine 2 allée André Guinier-Campus ARTEM BP 50840 54011 Nancy Cedex France Laboratoire CRISMAT UMR 6508 CNRS ENSICAEN 6 Boulevard du Maréchal Juin 14050 Caen Cedex 04 France Department of Physics and Science of Advanced Materials Program Central Michigan University Mt. Pleasant Michigan 48859 United States Solvay Design and Development of Functional Materials Department AXEL’ ONE Collaborative Platform − Innovative Materials 87 Rue des Freres Perret − BP62 69192 Saint Fons Cedex France Institut de Physique de Rennes UMR UR1-CNRS 6251 Université de Rennes I Campus de Beaulieu 35042 Rennes Cedex France Université de Rennes CNRS ISCR – UMR 6226 F-35000 Rennes France Laboratoire Léon Brillouin CNRS-CEA (UMR 12) CNRS Université Paris-Saclay CEA Saclay 91191 Gif-sur-Yvette Cedex France Research Institute for Energy Conservation National Institute of Advanced Industrial Science and Technology (AIST) Tsukuba Ibaraki 305–8568 Japan Department of Applied Science for Electronics and Materials Interdisciplinary Graduate School of Engineering Sciences Kyushu University Kasuga Fukuoka 816–8580 Japan

The influence of structural disorder on the thermal transport in the colusite Cu26V2Sn6S32 has been investigated by means of low-temperature thermal conductivity and specific heat measurements (2–300 K), Sn119 Mössbauer spectroscopy and temperature-dependent powder inelastic neutron scattering (INS). Variations in the high-temperature synthesis conditions act as a key parameter for tuning the degree of disorder in colusite compounds. Intriguingly, we find that all synthesized samples are disordered, the degree of which varies with the synthesis conditions used. Mössbauer data clearly evidence that Sn atoms do not solely occupy the 6c site of the crystal lattice but are present on possibly both the Cu and V sites, leading to a random distribution of these three cations within the unit cell. Increasing the disorder in these materials tends to lead to a smearing out of the main features in the phonon density of states measured by INS. Although the evolution of the inelastic signal upon warming is well described by a quasiharmonic approximation, elastic properties calculations indicate large average Grüneisen parameters, consistent with those determined experimentally from thermodynamic data. Increasing the level of disorder results in a decreased average Grüneisen parameter suggesting that the lowered lattice thermal conductivity is not driven by enhanced anharmonicity. These results provide experimental evidence to support that the remarkable changeover in the lattice thermal conductivity from crystalline to glasslike is solely driven by enhanced disorder accompanied by local lattice distortions.

关键词： Thermal properties Polycrystalline materials Mössbauer spectroscopy Time-of-flight neutron spectroscopy

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Engaging in research on fracture

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Zairyo/Journal of the Society of materials science, Japan 2018年第11期67卷 1028-1028页

作者： Matsuda, Shinya Department of Engineering and Design Faculty of Engineering and Design Kanagawa University Area in Advanced Materials Science Hayashi-cyo Takamatsu761-0396 Japan

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Radiation shielding properties of Nd0.6Sr0.4Mn1−yNiyO3 substitute with different concentrations of nickle

arXiv

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arXiv 2020年

作者： Hamad, M.Kh. Mhareb, M.H.A. Alajerami, Y.S. Sayyed, M.I. Saleh, Gameel Maswadeh, Y. Ziq, Kh.A. Physics Department King Fahd University of Petroleum and Minerals Dhahran31261 Saudi Arabia Department of Physics College of Science Imam Abdulrahman Bin Faisal University P.O. Box 1982 Dammam31441 Saudi Arabia Basic and Applied Scientific Research Center Imam Abdulrahman Bin Faisal University P.O. Box 1982 Dammam31441 Saudi Arabia Physics and Astronomy Science Faculty Ohio University United States Medical Imaging Department Applied Medical Sciences Faculty Al Azhar University-Gaza Department of Physics Faculty of Science University of Tabuk Tabuk Saudi Arabia Department of Biomedical Engineering College of Engineering Imam Abdulrahman Bin Faisal University P.O. Box 1982 Dammam Saudi Arabia Department of Physics and Science of Advanced Materials Program Central Michigan University Mt. PleasantMI48859 United States

In this work, we investigate the effect of Ni concentration on several shielding properties of Nd0.6Sr0.4Mn1−yNiyO3 (0.00≤y≤0.20) perovskite ceramic for possible use as radiation shielding materials. X-ray diffraction (XRD) analysis revealed that these ceramics have the orthorhombic structure with group space Pnma over a wide range of Ni-substitutions. Moreover, the analysis showed a nearly linear decrease in the lattice parameters and the unit cell volume (V) causing a gradual increase in the packing density with increasing Ni concentration. The shielding features for photons, neutrons, and protons of all ceramic samples were assessed. The mass attenuation coefficient (MAC) was computed at 0.1, 0.6, 1.25, 5 and 15 MeV by utilizing (MCNP) (version 5.0);the results were compared with the corresponding values obtained using Phy-X and XCOM program. The results obtained showed slight enhancement with increasing Ni contents. The substitution of Ni leads to progressive enhancement in effective removal cross-section of fast neutron (∑R) values. Whereas the values of Mass Stopping Power (MSP) and projected range for the protons showed a gradual reduction with increasing Ni concentration. These findings suggest that the current ceramic samples can be useful as radiation shielding materials. Copyright © 2020, The Authors. All rights reserved.

关键词： Radiation shielding

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Microstructural and Micro-Chemical Evolutions in Irradiated UCO Fuel Kernels of AGR-1 and AGR-2 TRISO Fuel Particles

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Journal of Physics: Conference Series 2021年第1期2048卷

作者： Zhenyu Fu Yong Yang Isabella J. Van Rooyen Subhashish Meher Boopathy Kombaiah Nuclear Engineering Program Department of Materials Science and Engineering University of Florida PO Box 116400 100 Rhines Hall Gainesville FL 32611 USA Fuel Design and Development Department Idaho National Laboratory Idaho Falls ID 83415-6188 USA Material Science Department Idaho National Laboratory Idaho Falls ID 83415-6188 USA Advanced Characterization Department Idaho National Laboratory Idaho Falls ID 83415-6188 USA

AGR-1 and AGR-2 tristructural-isotropic (TRISO) fuel particles were fabricated using slightly different fuel kernel chemical compositions, modified fabrication processes, different fuel kernel diameters, and changed 235U enrichments. Extensive microstructural and analytical characterizations were conducted to correlate those differences with the fuel kernels' responses to neutron irradiations in terms of irradiated fuel microstructure, fission products' chemical and physical states, and fission gas bubble evolutions. The studies used state-of-the-art transmission electron microscopy (TEM) equipped with energy-dispersive x-ray spectroscopy (EDS) via four silicon solid-state detectors with super sensitivity and rapid speed. The TEM specimens were prepared from selected AGR-1 and AGR-2 irradiated fuel kernels exposed to safety testing after irradiation. The particles were chosen in order to create representative irradiation conditions with fuel burnup in the range of 10.8 to 18.6% fissions per initial metal atom (FIMA) and time-average volume-average temperatures varying from 1070 to 1287°C. The 235U enrichment was 19.74 wt.% and 14.03 wt.% for the AGR-1 and AGR-2 fuel kernels, respectively. The TEM results showed significant microstructural reconstructions in the irradiated fuel kernels from both the AGR-1 and AGR-2 fuels. There are four major phases: fuel matrix of UO2 and UC, U2RuC2, and UMoC2—in the irradiated AGR-2 fuel kernel. Zr and Nd form a solid solution in the UC phase. The UMoC2 phase often features a detectable concentration of Tc. Pd was mainly found to be located in the buffer layer or associated with fission gas bubbles within the UMoC2 phase. EDS maps qualitatively show that rare-earth fission products (Nd et al.) preferentially reside in the UO2 phase. In contrast, in the irradiated AGR-1 fuel kernel, no U2RuC2 or UMoC2 precipitates were positively identified. Instead, there was a high number of rod-shaped precipitates enriched with Ru, Tc, Rh, and Pd

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EMPRESS. IX. Extremely Metal-Poor Galaxies are Very Gas-Rich Dispersion-Dominated Systems: Will JWST Witness Gaseous Turbulent High-z Primordial Galaxies?

arXiv

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arXiv 2022年

作者： Isobe, Yuki Ouchi, Masami Nakajima, Kimihiko Ozaki, Shinobu Bouché, Nicolas F. Wise, John H. Xu, Yi Emsellem, Eric Kusakabe, Haruka Hattori, Takashi Nagao, Tohru Chiaki, Gen Fukushima, Hajime Harikane, Yuichi Hayashi, Kohei Hirai, Yutaka Kim, Ji Hoon Maseda, Michael V. Nagamine, Kentaro Shibuya, Takatoshi Sugahara, Yuma Yajima, Hidenobu Aoyama, Shohei Fujimoto, Seiji Fukushima, Keita Hatano, Shun Inoue, Akio K. Ishigaki, Tsuyoshi Kawasaki, Masahiro Kojima, Takashi Komiyama, Yutaka Koyama, Shuhei Koyama, Yusei Lee, Chien-Hsiu Matsumoto, Akinori Mawatari, Ken Moriya, Takashi J. Motohara, Kentaro Murai, Kai Nishigaki, Moka Onodera, Masato Ono, Yoshiaki Rauch, Michael Saito, Tomoki Sasaki, Rin Suzuki, Akihiro Takeuchi, Tsutomu T. Umeda, Hiroya Umemura, Masayuki Watanabe, Kuria Yabe, Kiyoto Zhang, Yechi Institute for Cosmic Ray Research The University of Tokyo 5-1-5 Kashiwanoha Chiba Kashiwa277-8582 Japan Department of Physics Graduate School of Science The University of Tokyo 7-3-1 Hongo Bunkyo Tokyo113-0033 Japan National Astronomical Observatory of Japan 2-21-1 Osawa Mitaka Tokyo181-8588 Japan University of Tokyo Chiba Kashiwa277-8583 Japan Univ Lyon Univ Lyon1 ENS de Lyon CNRS Centre de Recherche Astrophysique de Lyon UMR5574 Saint-Genis-LavalF-69230 France Center for Relativistic Astrophysics School of Physics Georgia Institute of Technology AtlantaGA30332 United States Department of Astronomy Graduate School of Science The University of Tokyo 7-3-1 Hongo Bunkyo Tokyo113-0033 Japan European Southern Observatory Karl-Schwarzschild-Straße 2 Garching85748 Germany Observatoire de Genéve Université de Genéve 51 Ch. des Maillettes Versoix1290 Switzerland 650 North A'ohoku Place HiloHI96720 United States Research Center for Space and Cosmic Evolution Ehime University Bunkyo-cho 2-5 Ehime Matsuyama790-8577 Japan Center for Computational Sciences University of Tsukuba Ten-nodai 1-1-1 Tsukuba Ibaraki305-8577 Japan Department of Physics and Astronomy University College London Gower Street LondonWC1E 6BT United Kingdom National Institute of Technology Ichinoseki College Hagisho Ichinoseki021-8511 Japan Astronomical Institute Tohoku University 6-3 Aoba Aramaki Aoba-ku Miyagi Sendai980-8578 Japan Department of Physics and Astronomy University of Notre Dame 225 Nieuwland Science Hall Notre DameIN46556 United States Astronomy Program Department of Physics and Astronomy Seoul National University 1 Gwanak-ro Gwanak-gu Seoul08826 Korea Republic of SNU Astronomy Research Center Seoul National University 1 Gwanak-ro Gwanak-gu Seoul08826 Korea Republic of Department of Astronomy University of Wisconsin-Madison 475 N. Charter Street MadisonWI53706 United States Theoretical Astrophysics Department of Earth & Space S

We present kinematics of 6 local extremely metal-poor galaxies (EMPGs) with low metallicities (0.016 − 0.098 Z☉) and low stellar masses (104.7 − 107.6M☉). Taking deep medium-high resolution (R ∼ 7500) integral-field spectra with 8.2-m Subaru, we resolve the small inner velocity gradients and dispersions of the EMPGs with Hα emission. Carefully masking out sub-structures originated by inflow and/or outflow, we fit 3-dimensional disk models to the observed Hα flux, velocity, and velocity-dispersion maps. All the EMPGs show rotational velocities (vrot) of 5-23 km s−1 smaller than the velocity dispersions (σ0) of 17-31 km s−1, indicating dispersion-dominated (vrot/σ0 = 0.29−0.80 gas 0.9 − 1.0. Comparing our results with other Hα kinematics studies, we find that vrot/σ0 decreases and fgas increases with decreasing metallicity, decreasing stellar mass, and increasing specific star-formation rate. We also find that simulated high-z (z ∼ 7) forming galaxies have gas fractions and dynamics similar to the observed EMPGs. Our EMPG observations and the simulations suggest that primordial galaxies are gas-rich dispersion-dominated systems, which would be identified by the forthcoming James Webb Space Telescope (JWST) observations at z ∼ 7. Copyright © 2022, The Authors. All rights reserved.

关键词： Galaxies

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