1
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Changala PB, McCarthy MC. Rotational Spectrum of the Phenoxy Radical. J Phys Chem Lett 2024:5063-5069. [PMID: 38701387 DOI: 10.1021/acs.jpclett.4c00962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
We report the hyperfine-resolved rotational spectrum of the gas-phase phenoxy radical in the 8-25 GHz frequency range using cavity Fourier transform microwave spectroscopy. A complete assignment of its complex but well-resolved fine and hyperfine splittings yielded a precisely determined set of rotational constants, spin-rotation parameters, and nuclear hyperfine coupling constants. These results are interpreted with support from high-level quantum chemical calculations to gain detailed insight into the distribution of the unpaired π electron in this prototypical resonance-stabilized radical. The accurate laboratory rest frequencies enable studies of the chemistry of phenoxy in both the laboratory and space. The prospects of extending the present experimental and theoretical techniques to investigate the rotational spectra of isotopic variants and structural isomers of phenoxy and other important gas-phase radical intermediates that are yet undetected at radio wavelengths are discussed.
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Affiliation(s)
- P Bryan Changala
- Center for Astrophysics | Harvard & Smithsonian Cambridge, Massachusetts 02138, United States
| | - Michael C McCarthy
- Center for Astrophysics | Harvard & Smithsonian Cambridge, Massachusetts 02138, United States
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2
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Shiels OJ, Marlton SJP, Poad BLJ, Blanksby SJ, da Silva G, Trevitt AJ. Gas-Phase Phenyl Radical + O 2 Reacts via a Submerged Transition State. J Phys Chem A 2024; 128:413-419. [PMID: 38174881 DOI: 10.1021/acs.jpca.3c06878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
In the gas-phase chemistry of the atmosphere and automotive fuel combustion, peroxyl radical intermediates are formed following O2 addition to carbon-centered radicals which then initiate a complex network of radical reactions that govern the oxidative processing of hydrocarbons. The rapid association of the phenyl radical-a fundamental radical related to benzene-with O2 has hitherto been modeled as a barrierless process, a common assumption for peroxyl radical formation. Here, we provide an alternate explanation for the kinetics of this reaction by deploying double-hybrid density functional theory (DFT), at the DSD-PBEP86-D3(BJ)/aug-cc-pVTZ level of theory, and locate a submerged adiabatic transition state connected to a prereaction complex along the reaction entrance pathway. Using this potential energy scheme, experimental rate coefficients k(T) for the addition of O2 to the phenyl radical are accurately reproduced within a microcanonical kinetic model. This work highlights that purportedly barrierless radical oxidation reactions may instead be modeled using stationary points, which in turn provides insight into pressure and temperature dependence.
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Affiliation(s)
- Oisin J Shiels
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong 2522, Australia
| | - Samuel J P Marlton
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong 2522, Australia
| | - Berwyck L J Poad
- School of Chemistry and Physics and the Central Analytical Research Facility, Queensland University of Technology, Brisbane 4001, Australia
| | - Stephen J Blanksby
- School of Chemistry and Physics and the Central Analytical Research Facility, Queensland University of Technology, Brisbane 4001, Australia
| | - Gabriel da Silva
- Department of Chemical Engineering, the University of Melbourne, Melbourne 3010, Victoria, Australia
| | - Adam J Trevitt
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong 2522, Australia
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3
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Raj A, Thiraviam P, Elkadi M. A Reaction Kinetics Study on Benzene Oxidation in the Claus Process by Sulfur Monoxide. J Phys Chem A 2023; 127:1013-1025. [PMID: 36669093 DOI: 10.1021/acs.jpca.2c06586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The Claus process is used in natural gas processing plants to treat H2S-rich acid gas to recover sulfur, but the process suffers from catalytic deactivation when aromatic contaminants such as benzene, toluene, ethylbenzene, and xylene isomers (collectively called as BTEX) are present in the acid gas feed. To safeguard the catalytic reactors, it is desired to oxidize aromatic contaminants in the furnace that are present upstream of the catalytic reactors in the process by oxidants present in it. This work develops a reaction mechanism and evaluates the reaction kinetics for the oxidation of phenyl radical by SO using CBS-QBS for reaction energetics and RRKM and transition state theory for reaction kinetics. The mechanism explores the possible products that are formed from the barrierless addition of SO on phenyl through the O atom as well as through the S atom. The exothermicity of the addition reaction is higher when the addition of SO on the aromatic structure takes place through the S atom. The major products formed from phenyl oxidation by SO are cyclopentadienyl, cyclopentadienethiol and thiopyran radicals. A remarkable similarity between the pathways for phenyl radical oxidation by O2 and its oxidation by SO at high temperatures is observed. The proposed reactions and their rate constants are used to conduct reactor simulations to determine the important reactions that contribute to the formation of major products during phenyl-SO reactions and the temperatures suitable for benzene oxidation by SO under process conditions similar to the Claus furnace.
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Affiliation(s)
- Abhijeet Raj
- Department of Chemical Engineering, Indian Institute of Technology Delhi, New Delhi110016, India
| | - Preethika Thiraviam
- Department of Chemistry, Khalifa University of Science and Technology, P.O. Box 127788, Abu Dhabi, UAE.,Department of Chemical Engineering, Birla Institute of Technology and Science, Pilani, Dubai Campus, P.O. Box 345055, Dubai, UAE
| | - Mirella Elkadi
- Department of Chemistry, Khalifa University of Science and Technology, P.O. Box 127788, Abu Dhabi, UAE
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4
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Morozov AN, Medvedkov IA, Azyazov VN, Mebel AM. Theoretical Study of the Phenoxy Radical Recombination with the O( 3P) Atom, Phenyl plus Molecular Oxygen Revisited. J Phys Chem A 2021; 125:3965-3977. [PMID: 33929861 DOI: 10.1021/acs.jpca.1c01545] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Quantum chemical calculations of the C6H5O2 potential energy surface (PES) were carried out to study the mechanism of the phenoxy + O(3P) and phenyl + O2 reactions. CASPT2(15e,13o)/CBS//CASSCF(15e,13o)/DZP multireference calculations were utilized to map out the minimum energy path for the entrance channels of the phenoxy + O(3P) reaction. Stationary points on the C6H5O2 PES were explored at the CCSD(T)-F12/cc-pVTZ-f12//B3LYP/6-311++G** level for the species with a single-reference character of the wave function and at the CASPT2(15e,13o)/CBS//B3LYP/6-311++G** level of theory for the species with a multireference character of the wave function. Conventional, variational, and variable reaction coordinate transition-state theories were employed in Rice-Ramsperger-Kassel-Marcus master equation calculations to assess temperature- and pressure-dependent phenomenological rate constants and product branching ratios. The main bimolecular product channels of the phenoxy + O(3P) reaction are concluded to be para/ortho-benzoquinone + H, 2,4-cyclopentadienone + HCO and, at high temperatures, also phenyl + O2. The main bimolecular product channels of the phenyl + O2 reaction include 2,4-cyclopentadienone + HCO at lower temperatures and phenoxy + O(3P) at higher temperatures. For both the phenoxy + O(3P) and phenyl + O2 reactions, the collisional stabilization of peroxybenzene at low temperatures and high pressures competes with the bimolecular product channels.
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Affiliation(s)
- Alexander N Morozov
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
| | - Iakov A Medvedkov
- Samara National Research University, Samara 443086, Russian Federation.,Lebedev Physical Institute, Samara 443011, Russian Federation
| | - Valeriy N Azyazov
- Samara National Research University, Samara 443086, Russian Federation.,Lebedev Physical Institute, Samara 443011, Russian Federation
| | - Alexander M Mebel
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
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5
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Zhao L, Prendergast M, Kaiser RI, Xu B, Ablikim U, Lu W, Ahmed M, Oleinikov AD, Azyazov VN, Howlader AH, Wnuk SF, Mebel AM. How to add a five-membered ring to polycyclic aromatic hydrocarbons (PAHs) – molecular mass growth of the 2-naphthyl radical (C10H7) to benzindenes (C13H10) as a case study. Phys Chem Chem Phys 2019; 21:16737-16750. [DOI: 10.1039/c9cp02930c] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reaction of aryl radicals with allene/methylacetylene leads to five-membered ring addition in PAH growth processes.
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Affiliation(s)
- Long Zhao
- Department of Chemistry
- University of Hawaii at Manoa
- Honolulu
- USA
| | | | - Ralf I. Kaiser
- Department of Chemistry
- University of Hawaii at Manoa
- Honolulu
- USA
| | - Bo Xu
- Chemical Sciences Division
- Lawrence Berkeley National Laboratory
- Berkeley
- USA
| | - Utuq Ablikim
- Chemical Sciences Division
- Lawrence Berkeley National Laboratory
- Berkeley
- USA
| | - Wenchao Lu
- Chemical Sciences Division
- Lawrence Berkeley National Laboratory
- Berkeley
- USA
| | - Musahid Ahmed
- Chemical Sciences Division
- Lawrence Berkeley National Laboratory
- Berkeley
- USA
| | | | | | - A. Hasan Howlader
- Department of Chemistry and Biochemistry
- Florida International University
- Miami
- USA
| | - Stanislaw F. Wnuk
- Department of Chemistry and Biochemistry
- Florida International University
- Miami
- USA
| | - Alexander M. Mebel
- Department of Chemistry and Biochemistry
- Florida International University
- Miami
- USA
- Samara National Research University
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6
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Thomas AM, Yang T, Dangi BB, Kaiser RI, Kim GS, Mebel AM. Oxidation of the para-Tolyl Radical by Molecular Oxygen under Single-Collison Conditions: Formation of the para-Toloxy Radical. J Phys Chem Lett 2016; 7:5121-5127. [PMID: 27973866 DOI: 10.1021/acs.jpclett.6b02357] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Crossed molecular beam experiments were performed to elucidate the chemical dynamics of the para-tolyl (CH3C6H4) radical reaction with molecular oxygen (O2) at an average collision energy of 35.3 ± 1.4 kJ mol-1. Combined with theoretical calculations, the results show that para-tolyl is efficiently oxidized by molecular oxygen to para-toloxy (CH3C6H4O) plus ground-state atomic oxygen via a complex forming, overall exoergic reaction (experimental, -33 ± 16 kJ mol-1; computational, -42 ± 8 kJ mol-1). The reaction dynamics are analogous to those observed for the phenyl (C6H5) plus molecular oxygen system which suggests the methyl group is a spectator during para-tolyl oxidation and that application of phenyl thermochemistry and reaction rates to para-substituted aryls is likely a suitable approximation.
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Affiliation(s)
- Aaron M Thomas
- Department of Chemistry, University of Hawai'i at Ma̅noa , Honolulu, Hawaii 96822, United States
| | - Tao Yang
- Department of Chemistry, University of Hawai'i at Ma̅noa , Honolulu, Hawaii 96822, United States
| | - Beni B Dangi
- Department of Chemistry, University of Hawai'i at Ma̅noa , Honolulu, Hawaii 96822, United States
| | - Ralf I Kaiser
- Department of Chemistry, University of Hawai'i at Ma̅noa , Honolulu, Hawaii 96822, United States
| | - Gap-Sue Kim
- Dharma College, Dongguk University , 30, Pildong-ro 1-gil, Jung-gu, Seoul 04620, South Korea
| | - Alexander M Mebel
- Department of Chemistry and Biochemistry, Florida International University , Miami, Florida 33199, United States
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7
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Li S, Zhang Q. Mechanistic studies on the dibenzofuran and dibenzo-p-dioxin formation reactions from o-benzyne precursor. COMPUT THEOR CHEM 2015. [DOI: 10.1016/j.comptc.2015.03.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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8
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Singh RI, Mebel AM, Frenklach M. Oxidation of Graphene-Edge Six- and Five-Member Rings by Molecular Oxygen. J Phys Chem A 2015; 119:7528-47. [DOI: 10.1021/acs.jpca.5b00868] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ravi I. Singh
- Department
of Mechanical Engineering, University of California at Berkeley, Berkeley, California 94720-1740, United States
| | - Alexander M. Mebel
- Department
of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
| | - Michael Frenklach
- Department
of Mechanical Engineering, University of California at Berkeley, Berkeley, California 94720-1740, United States
- Environmental
Energy Technologies Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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9
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Parker DSN, Kaiser RI, Troy TP, Kostko O, Ahmed M, Mebel AM. Toward the Oxidation of the Phenyl Radical and Prevention of PAH Formation in Combustion Systems. J Phys Chem A 2014; 119:7145-54. [DOI: 10.1021/jp509170x] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Dorian S. N. Parker
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
| | - Ralf I. Kaiser
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
| | - Tyler P. Troy
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Oleg Kostko
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Musahid Ahmed
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Alexander M. Mebel
- Department of Chemistry and
Biochemistry, Florida International University, Miami, Florida 33199, United States
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10
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Cole-Filipiak NC, Shapero M, Negru B, Neumark DM. Revisiting the photodissociation dynamics of the phenyl radical. J Chem Phys 2014; 141:104307. [DOI: 10.1063/1.4894398] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Neil C. Cole-Filipiak
- Department of Chemistry, University of California, Berkeley, California 94720, USA and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Mark Shapero
- Department of Chemistry, University of California, Berkeley, California 94720, USA and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Bogdan Negru
- Department of Chemistry, University of California, Berkeley, California 94720, USA and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Daniel M. Neumark
- Department of Chemistry, University of California, Berkeley, California 94720, USA and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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11
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Sinha S, Raj A, AlShoaibi AS, Alhassan SM, Chung SH. Benzene Destruction in Claus Process by Sulfur Dioxide: A Reaction Kinetics Study. Ind Eng Chem Res 2014. [DOI: 10.1021/ie501732a] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
| | | | | | | | - Suk Ho Chung
- Clean
Combustion Research Centre, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
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12
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Parker DS, Yang T, Kaiser RI, Landera A, Mebel AM. On the formation of ethynylbiphenyl (C14D5H5; C6D5C6H4CCH) isomers in the reaction of D5-phenyl radicals (C6D5; X2A1) with phenylacetylene (C6H5C2H; X1A1) under single collision conditions. Chem Phys Lett 2014. [DOI: 10.1016/j.cplett.2014.02.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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13
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Freel KA, Sullivan MN, Park J, Lin MC, Heaven MC. Structure in the Visible Absorption Bands of Jet-Cooled Phenylperoxy Radicals. J Phys Chem A 2013; 117:7484-91. [DOI: 10.1021/jp401570q] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Keith A. Freel
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Michael N. Sullivan
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - J. Park
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - M. C. Lin
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Michael C. Heaven
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
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14
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Albert DR, Davis HF. Studies of bimolecular reaction dynamics using pulsed high-intensity vacuum-ultraviolet lasers for photoionization detection. Phys Chem Chem Phys 2013; 15:14566-80. [DOI: 10.1039/c3cp51930a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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15
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Zhou CW, Kislov VV, Mebel AM. Reaction Mechanism of Naphthyl Radicals with Molecular Oxygen. 1. Theoretical Study of the Potential Energy Surface. J Phys Chem A 2012; 116:1571-85. [DOI: 10.1021/jp2119313] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Chong-Wen Zhou
- Department of Chemistry and
Biochemistry, Florida International University, 11200 SW 8th Street, Miami, Florida 33199, United States
- College of Chemical Engineering, Sichuan University, Chengdu 610065, People’s
Republic of China
| | - Vadim V. Kislov
- Department of Chemistry and
Biochemistry, Florida International University, 11200 SW 8th Street, Miami, Florida 33199, United States
| | - Alexander M. Mebel
- Department of Chemistry and
Biochemistry, Florida International University, 11200 SW 8th Street, Miami, Florida 33199, United States
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16
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Kaiser RI, Mebel AM. On the formation of polyacetylenes and cyanopolyacetylenes in Titan's atmosphere and their role in astrobiology. Chem Soc Rev 2012; 41:5490-501. [DOI: 10.1039/c2cs35068h] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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