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Academic literature on the topic 'Radical ion pair'

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Published: 4 June 2021
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Journal articles on the topic "Radical ion pair"

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Yuan, Ningning, Wenqing Wang, Ziye Wu, Sheng Chen, Gengwen Tan, Yunxia Sui, Xinping Wang, Jun Jiang, and Philip P. Power. "A boron-centered radical: a potassium-crown ether stabilized boryl radical anion." Chemical Communications 52, no. 86 (2016): 12714–16. http://dx.doi.org/10.1039/c6cc06918e.

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Lim, Gary N., Whitney A. Webre, and Francis D'Souza. "Charge separation in supramolecular ferrocene(s)-zinc porphyrin-fullerene triads: A femtosecond transient absorption study." Journal of Porphyrins and Phthalocyanines 19, no. 01-03 (January 2015): 270–80. http://dx.doi.org/10.1142/s108842461550008x.

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Mechanistic aspects of photoinduced charge separation in supramolecular triads, constructed using covalently linked zinc porphyrin-ferrocene(s) dyads — self-assembled via axial coordination to either pyridine or phenylimidazole appended fulleropyrrolidine ( Fc x- ZnP : PyC 60 or Fc x- ZnP : ImC 60; x = 1 or 2), has been investigated using femtosecond pump-probe transient spectroscopy. Upon photoexcitation of ZnP , charge separation from ferrocene to 1 ZnP * to yield the initial Fc +- ZnP •-: C 60 radical ion-pair or charge separation from 1 ZnP * to C 60 to yield the initial Fc - ZnP •+: C 60•- radical ion-pair, depending upon the ferrocene-zinc porphyrin intermolecular distance, was observed. These radical ion-pairs resulted in the formation of ultimate distantly separated Fc +- ZnP : C 60•- radical ion-pairs either via an electron migration (former case) or hole shift (latter case) process. Kinetics of charge separation as a function of spacer connecting the ferrocene and porphyrin, and spacer between the porphyrin and fullerene is reported. In agreement with our earlier study (J. Phys. Chem. B 2004; 108: 11333–11343), the Fc +- ZnP : C 60•- radical ion-pair persisted beyond the monitoring time window of our instrument, suggesting charge stabilization in these supramolecular triads.
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Jones II, Guilford, Xiaochun Wang, and Jingqiu Hu. "Photochemistry of rhodamine dye salts involving intra-ion-pair electron transfer." Canadian Journal of Chemistry 81, no. 6 (June 1, 2003): 789–98. http://dx.doi.org/10.1139/v03-074.

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The electron-transfer photochemistry of rhodamine 6G thiocyanate ion pairs has been investigated. For dye in a low polarity solvent, such as ethyl acetate, the emission of rhodamine 6G is significantly quenched by thiocyanate counterions. Laser photolysis of rhodamine 6G and thiocyanate in ethyl acetate was studied in detail with the identification of the reduced rhodamine 6G radical species (λmax = 410 nm). The growth and decay of the R6G radical could be accounted for in part by a mechanism involving initial formation of dye triplet followed by electron transfer which provides a triplet radical-pair state on a µs timescale.Key words: electron transfer, ion pair, rhodamine 6G, triplet state.
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Kim, J. M., and J. A. Pincock. "Internal return in the photochemistry of ring-substituted 1-(1-naphthyl)ethyl esters of phenylacetic acid." Canadian Journal of Chemistry 73, no. 6 (June 1, 1995): 885–95. http://dx.doi.org/10.1139/v95-111.

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The photochemistry in methanol of the esters 12a–d has been studied in order to determine the importance of internal return of both ion pair and radical pair intermediates. The efficiency of internal return, determined by monitoring 18O exchange between the alcohol and carbonyl oxygens, was shown to be substituent dependent, varying from approximately 10% for the 4,7-dimethoxy substrate to nearly 50% for the 4-cyano case. The corresponding ground state solvolysis reactions gave about 10% internal return and, within experimental error, were substituent independent. Internal return was also examined by racemization of the chiral center in 12a and 12d. In summary, these combined results reveal that internal return probably occurs mainly through a contact (not solvent-separated) radical pair. More important, internal return has little effect on previously calculated electron transfer rate constants for converting the radical pair to the ion pair. Therefore, the previously reported Marcus' correlations are valid. Keywords: photochemistry of benzylic esters, internal return, photosolvolysis, electron transfer, radical pairs.
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Morlet-Savary, F., J. P. Fouassier, Hideo Tomioka, Iwao Sumiyoshi, and Yasuyuki Takimoto. "Ion and Radical Pair Generation in Tribromoacetophenone." Chemistry Letters 26, no. 12 (December 1997): 1267–68. http://dx.doi.org/10.1246/cl.1997.1267.

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Aramaki, Yoshitaka, Naoki Imaizumi, Mao Hotta, Jun Kumagai, and Takashi Ooi. "Exploiting single-electron transfer in Lewis pairs for catalytic bond-forming reactions." Chemical Science 11, no. 17 (2020): 4305–11. http://dx.doi.org/10.1039/d0sc01159b.

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Goez, Martin, Isabell Frisch, and Ingo Sartorius. "Electron and hydrogen self-exchange of free radicals of sterically hindered tertiary aliphatic amines investigated by photo-CIDNP." Beilstein Journal of Organic Chemistry 9 (February 26, 2013): 437–46. http://dx.doi.org/10.3762/bjoc.9.46.

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The photoreactions of diazabicyclo[2,2,2]octane (DABCO) and triisopropylamine (TIPA) with the sensitizers anthraquinone (AQ) and xanthone (XA) or benzophenone (BP) were investigated by time-resolved photo-CIDNP (photochemically induced dynamic nuclear polarization) experiments. By varying the radical-pair concentration, it was ensured that these measurements respond only to self-exchange reactions of the free amine-derived radicals (radical cations DH • + or α-amino alkyl radicals D • ) with the parent amine DH; the acid–base equilibrium between DH • + and D • also plays no role. Although the sensitizer does not at all participate in the observed processes, it has a pronounced influence on the CIDNP kinetics because the reaction occurs through successive radical pairs. With AQ, the polarizations stem from the initially formed radical-ion pairs, and escaping DH • + then undergoes electron self-exchange with DH. In the reaction sensitized with XA (or BP), the polarizations arise in a secondary pair of neutral radicals that is rapidly produced by in-cage proton transfer, and the CIDNP kinetics are due to hydrogen self-exchange between escaping D • and DH. For TIPA, the activation parameters of both self-exchange reactions were determined. Outer-sphere reorganization energies obtained with the Marcus theory gave very good agreement between experimental and calculated values of ∆G ‡ 298.
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Murai, Hisao, Yoshinori Yamamoto, and Yasumasa J. I'Haya. "Time-resolved ESR study on photochemical formation of radical pair in cyclodextrin cavities." Canadian Journal of Chemistry 69, no. 11 (November 1, 1991): 1643–48. http://dx.doi.org/10.1139/v91-241.

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The photoreduction of xanthone with diethylaniline in cyclodextrin cavities was studied at 77 K and room temperature by a time-resolved ESR technique. The radical pair observed in β- and γ-cyclodextrins showed inverted spin polarization compared to that of precursor excited triplet xanthone. This result is rationalized by taking account of the fixed orientation of the radical ion pair in the cyclodextrins. Frozen aqueous solutions and dried powder-like samples provided similar results. The spectrum of the radical pair was also detected in an aqueous solution of β-cyclodextrin at room temperature. Key words: cyclodextrins, xanthone, spin polarization, radical ion-pair, time-resolved ESR.
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John, Andreas, and Hans Bock. "Elektronentransfer und Kontaktionen-Bildung, 42 [1,2] Cyclovoltammetrische und ESR / ENDOR-Untersuchungen der Einelektronen-Reduktion von Diphenochinonen / Electron Transfer and Contact Ion Pair Formation, 42 [1,2] Cyclovoltammetric and ESR / ENDOR Investigations of the One-Electron Reduction of Diphenoquinones." Zeitschrift für Naturforschung B 50, no. 11 (November 1, 1995): 1699–716. http://dx.doi.org/10.1515/znb-1995-1118.

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Semiquinone radical anions are prototype compounds for contact ion pair formation with metal counter cations. In order to investigate the still open question whether bulky alkyl groups can sterically interfere, diphenoquinone derivatives O=C(RC=CH)2C=C(HC=CR)2C=O with R = C(CH3)3, CH(CH3)2 and CH3 have been selected and the following ESR/ENDOR results are obtained for the alkaline metal cations: The tetrakis(tert-butyl)-substituted radical anion only adds Li⊕ and Na⊕, while K⊕ forms no ion pair. The 3,3ʹ,5,5ʹ-tetra(isopropyl)diphenoquinone radical anion is accessible to all cations Me⊕, although Rb⊕ and Cs⊕ seem to be present solvent-separated in solution. The tetramethyl-substituted radical anion unfortunately polymerizes rapidly. Additional information concerns the ESR/ENDOR proof for ion triple radical cation formation [Li⊕ M•⊖Li⊕]•⊕, or the difference in the coupling constants upon Me⊕ docking at one δ⊖O=C group, suggesting that about 87% of the spin density is located in the cation-free molecular half of the diphenoquinone radical anion. Based on the wealth of ESR/ENDOR information, crystallization of the contact ion pairs and their structural characterization should be attempted.
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Morack, Tobias, Christian Mück‐Lichtenfeld, and Ryan Gilmour. "Bioinspired Radical Stetter Reaction: Radical Umpolung Enabled by Ion‐Pair Photocatalysis." Angewandte Chemie International Edition 58, no. 4 (January 21, 2019): 1208–12. http://dx.doi.org/10.1002/anie.201809601.

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Dissertations / Theses on the topic "Radical ion pair"

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Harman, David Grant, and harmandg@hotmail com. "Mechanisms of the Intriguing Rearrangements of Activated Organic Species." The Australian National University. Faculty of Science, 2003. http://thesis.anu.edu.au./public/adt-ANU20031210.143110.

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The β-acyloxyalkyl radical rearrangement has been known since 1967 but its mechanism is still not fully understood, despite considerable investigation. Since the migration of a β-trifluoroacetoxy group generally proceeds more rapidly and with more varied regiochemistry than its less electronegative counterparts, this reaction was studied in the hope of understanding more about the subtleties of the mechanism of the β- acyloxyalkyl radical rearrangement. The mechanism of the catalysed rearrangement of Nalkoxy- 2(1H)-pyridinethiones was also explored because preliminary studies indicated that the transition state (TS) for this process was isoelectronic with TSs postulated for the β-acyloxyalkyl radical and other novel rearrangements. ¶ A kinetic study of the rearrangement of the 2-methyl-2-trifluoroacetoxy-1-heptyl radical in solvents of different polarity was undertaken using a radical clock method. Arrhenius equations for the rearrangement in each solvent were: hexane, log10[kr (s-1)] = 11.8±0.3 – (48.9±0.7)/ θ; benzene, log10[kr (s-1)] = 12.0±0.2 – (43.7±0.8)/ θ; and propionitrile, log10[kr (s-1)] = 11.9±0.2 – (42.0±0.3)/ θ. Rate constants at 75˚C were: hexane, kr = 2.9 × 104; benzene, kr = 2.8 × 105; and propionitrile, kr = 4.0 × 105 s-1. The equilibrium constant for the reversible rearrangement at 80°C in benzene was 15.1
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Brun, Pierre-Hervé. "Modèle de chondrocytes articulaires de lapin en culture "irrites" par des ions superoxydés." Paris 5, 1988. http://www.theses.fr/1988PA05P051.

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Poudel, Pramod Prasad. "NOVEL AROMATIC ION–PAIRS: SYNERGY BETWEEN ELECTROSTATICS AND Π-FACE AROMATIC INTERACTIONS." UKnowledge, 2012. http://uknowledge.uky.edu/chemistry_etds/4.

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This dissertation focuses on the design and study of charged aromatic molecules where weak π-π interactions synergize with electrostatic interactions to enhance the overall interaction between aromatic moieties. Each chapter investigates some aspect of this hypothetical synergy between electrostatics and π-face aromatic cohesion. The first chapter unveiled the importance of electrostatics in the intramolecular stacking of flexible aromatic molecular templates 1-2Br and 2a. While our previous studies found dicationic molecular template 1-2Br to have intramolecular π-stacking between electron poor pyridinium and electron rich xylylene moieties, no such stacking interaction was observed in the neutral analog 2a. Chapter two systematically explored the stacking pattern of electron poor aromatics in the form of oxygen- and / or nitrogen- substituted triangulenium cations, [1(NR)3]+ and [1(O)3(OH)3]+. As indicated in the chemical literature, triazatriangulenium cations [1(NR)3]+ with N- ethyl (and longer alkyl chains) chains were found to pack as face-to-face dimers. This study found the formation of columnar, face-to-face, n-meric association between aromatic cations in the structures with decreased steric interactions of the side chains in the stacking planes ([1(NMe)3]+ and [1(O)3(OH)3]+). Similar iso-structural triangulene based aromatic anions, (2)- and (3)2- didn’t indicate any facial interactions in the solid states. The possible synergy between unit charge electrostatics and π-face aromatic interactions was explored in aromatic ion pairs 1•2 of triangulene based aromatic cations and aromatic anions. This charge-assisted π-π stacking seems to be the novel way of getting strong π-system interactions where the strongest non-covalent force and the weakest non-covalent force: ionic bonding and π-stacking respectively synergize together. The π-π interaction between ionic aromatics in the solid state was investigated by means of single crystal x-ray diffraction and powder x-ray diffraction (PXRD). The interaction in the solution state was examined by UV-Vis spectroscopy, electrospray ionization mass spectroscopy (ESI-MS) and electrochemical studies. Studies found that optimal synergy was possible only in the ion pairs with no steric interactions of alkyl (or aryl) side chains in the stacking planes (1(O)3•2 & 1(NMe)3•2) and the interaction was found to be comparable with the strongest radical-assisted π-stacking described in the chemical literature.
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Laplanche, Loïc. "Le glutamate induit la production de radicaux libres oxygénés dans le striatum de rat : étude par microdialyse intracérébrale." Montpellier 1, 2002. http://www.theses.fr/2002MON13504.

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L'excitotoxicité glutamatergique et la formation de radicaux libres oxygénés sont associées à de nombreuses pathologies neurodégénératives. Malheureusement, les approches thérapeutiques pour lutter contre l'excitotoxicité et le stress oxydatif n'ont pas pour le moment apporté de réponse satisfaisante, du fait du manque de connaissances fondamentales quant aux mécanisme les reliant. Afin de mieux comprendre ces mécanismes, nous avons choisi d'étudier, in vito, la libération des radicaux libres oxygénés, hydroxyles en particulier, en réponse à une stimulation glutamatergique, au moyen d'une sonde de microdialyse implantée dans le striatum de rat vigile. En utilisant une approche pharmacologique, nous avons montré dans une première étape, que l'intervention des récepteurs de type NMDA est limitée aux circonstances où le glutamate est introduit ( ou libéré par un événement pathologique) de façon massive. Dans une deuxième étape, nous avons mies en lumière le rôle prépondérant du transport astrocytaire du glutamate dans la génération de radicaux hydroxyles lors d'une stimulation par des concentrations plus modérées de glutamate. Pour confirmer que les astrocytes sont probablement responsables de la libération des radicaux hydroxyles dans ces conditions, nous avons utilisé une troisième approche ( basée sur des perfusions répétitives des animaux ). Compte tenu des données de la littérature et de l'ensemble de nos résultats, nous proposons à ce stade de considérer que le transport du glutamate dans les astrocytes joue un rôle-si ce n'est le rôle- fondamental dans la production des radicaux libres oxygénés en réponse à une perturbation de la transmission glutamatergique. Un tel mécanisme pourrait fournir une base conceptuelle à de nouvelles stratégies de protection au moyen de pièges des radicaux libres.
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Saffré, Dimitri. "Radiolyse de l’eau dans des conditions extrêmes de température et de TEL. Capture de HO• par les ions Br-." Thesis, Paris 11, 2011. http://www.theses.fr/2011PA112246/document.

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L’objectif de cette thèse est de contribuer à la compréhension du mécanisme d’oxydation de Br- dans lequel le radical HO• intervient. Le rendement du radical HO• étant alors intimement lié au rendement d’oxydation de Br-, c’est sur lui que l'influence de différents paramètres physicochimiques a été étudiée : température, TEL, débit de dose, pH, nature du gaz saturant. Les solutions ont été irradiées avec 4 types de rayonnement : rayons X de 13 à 18 keV, électrons de 7 et 10 MeV, faisceaux d’ions C6+ de 975 MeV et He2+ de 70 MeV. Le développement d’un autoclave optique avec circulation de solution compatible avec le rayonnement de TEL élevé a permis de réaliser les premières expériences à TEL élevé constant et à température élevée. Cette cellule s’est avérée être aussi compatible avec les expériences pompe-sonde picoseconde réalisées avec l’accélérateur ELYSE.Le rendement de capture du radical hydroxyle a donc été estimé à TEL élevé mais aussi à haute température. Une meilleure compréhension du mécanisme d’oxydation de Br- en est issue, notamment en milieu acide et en comparant les résultats cinétiques avec les simulations Monte Carlo pour les temps inférieurs à la µs, et Chemsimul pour les produits stables (formation de Br2•- et de Br3-)
The purpose of this thesis is to contribute to the understanding of the oxidation mechanism of Br- in which the HO• radical is involved. The HO• radiolytic yield is strongly connected with the oxidation yield of Br-, and therefore we have studied the influence of different physical and chemical parameters on this global yield: temperature, LET, dose rate, pH, saturation gas. The solutions have been irradiated with 4 types of ionizing rays: X- rays (from 13 to 18 keV), electrons (from 7 to 10 MeV), C6+-ions beam of 975 MeV and He2+-ions beam of 70 MeV.The development of an optical autoclave with solution flow, compatible with high LET ionizing rays has allowed us conduct the first experiments at constant high LET and high temperature. This cell has turned out to be compatible with the picosecond pump-probe experiments performed with the ELYSE accelerator.The HO• scavenging yield has been, therefore, estimated at both high LET and high temperature. A better understanding of the Br- oxidation mechanism has been achieved, in acid medium, in particular, by comparing the kinetics results with Monte Carlo Simulations for time scales inferior to the microsecond and with Chemsimul for the stable products (Br2•- and Br3- formations)
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Saffré, Dimitri. "Radiolyse de l'eau dans des conditions extrêmes de température et de TEL. Capture de HO* par les ions Br-." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00904672.

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L'objectif de cette thèse est de contribuer à la compréhension du mécanisme d'oxydation de Br- dans lequel le radical HO* intervient. Le rendement du radical HO* étant alors intimement lié au rendement d'oxydation de Br-, c'est sur lui que l'influence de différents paramètres physicochimiques a été étudiée : température, TEL, débit de dose, pH, nature du gaz saturant. Les solutions ont été irradiées avec 4 types de rayonnement : rayons X de 13 à 18 keV, électrons de 7 et 10 MeV, faisceaux d'ions C6+ de 975 MeV et He2+ de 70 MeV. Le développement d'un autoclave optique avec circulation de solution compatible avec le rayonnement de TEL élevé a permis de réaliser les premières expériences à TEL élevé constant et à température élevée. Cette cellule s'est avérée être aussi compatible avec les expériences pompe-sonde picoseconde réalisées avec l'accélérateur ELYSE.Le rendement de capture du radical hydroxyle a donc été estimé à TEL élevé mais aussi à haute température. Une meilleure compréhension du mécanisme d'oxydation de Br- en est issue, notamment en milieu acide et en comparant les résultats cinétiques avec les simulations Monte Carlo pour les temps inférieurs à la µs, et Chemsimul pour les produits stables (formation de Br2*- et de Br3-).
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Le, Giang Truong. "Influence des ions chlorure, nitrate et sulfate sur les vitesses de décomposition de H2O2 et d'oxydation de composés organiques par les systèmes Fe(II)/H2O2 et Fe(III)/H2O2 : étude spectrophotométrique et modélisation cinétique." Poitiers, 2003. http://www.theses.fr/2003POIT2290.

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L'objectif de cette thèse a été d'étudier et de modélise l'influence des ions chlorures et sulfates sur les vitesses de décomposition des H2O2 et d'oxydation de composés organiques par les systèmes Fe(II)/H2O2 et Fe(III)/H2O2 en phase homogène, à pH acide et à 25 ʿC. L'étude du système Fe(II)/H2O2 a permis de montrer que les constantes cinétiques apparentes de réaction de H2O2 sur Fe2+, FeCl+ et FeSO4 sont respectivement égales à 55, 55, 78 M-1 s-1. Pour le système Fe(III)/H2O2, la complexation de Fe(III) par les ions chlorures et sulfates conduit à une diminution de la concentration hydroperoxycomplexes de Fe(III) et explique la diminution des vitesses de décomposition de H2O2 et des vitesse d'oxydation de composés organiques. La formation de radicaux Cl2·- qui sont beaucoup moins réactifs que les radicaux hydroxyles contribue également à la diminution des vitesses d'oxydation des composés organiques. Toutes les vitesses expérimentales ont été correctement modélisées
The influence of chloride and sulfate ions on the rates of decomposition of H2O2 and of oxidation of organic compounds by the Fe(II)/H2O2 and Fe(III)/H2O2 has been investigated. Experiments were conducted at acidic pH and 25 ʿC. For the Fe(II)/H2O2 system, the rate constants for the reaction of H2O2 with Fe2+, FeCl+ and FeSO4 were found to be equal to 55, 55 ; 78 M-1 s-1. For the Fe(III)/H2O2 system, complexation reactions of Fe(III) by chloride or sulphate inhibit the formation of iron(III) hydroperoxycomplexes and lead to a decrease of the rates of decomposition of H2O2 and of the rates of oxidation of organic compounds. The formation of Cl2·- radicals which are less reactive than hydroxyl radicals also contribute to a decrease of the rates of oxidation of organic compounds. The reaction rates obtained in this study could be predicted well by a kinetic model
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Cunha, De Miranda Barbara Kelly. "Estudo da fotoionização de radicais e reações íon-molécula de interesse planetário, através de radiação VUV síncrotron e laser." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00619442.

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Ce travail a pour motivation de fournir des données expérimentales importantes pour l'interprétation de la chimie des ionosphère planétaires, en particulier pour le plus grand satellite de Saturne, Titan. On s'intéresse spécifiquement à la réactivité des espèces ioniques excitées. Cette thèse porte, d'une part, sur des expériences de préparation des cations (CH3+ et CF3+) sélectionnés en énergie interne par photoionisation VUV d'espèces neutres, et d'autre part, sur des réactions de cations sélectionnés en énergie interne avec des molécules, O+ avec CH4 et N+(3P) avec C3H4, C3H6 et C3H8.L'étude de la préparation des cations CH3+ et CF3+ sélectionnés dans des niveaux vibrationnels a été réalisée par la technique de coïncidence TPEPICO et du rayonnement VUV synchrotron à SOLEIL. Un spectromètre de type PFI-ZEKE qui permet d'atteindre une résolution de 0.84 cm-1 a été construit pour la réalisation d'études complémentaires avec le rayonnement laser VUV du Centre Laser de l'Université Paris Sud (CLUPS), à Orsay en France.Les expériences pour la détermination de l'influence de l'excitation du cation O+ (2S,2D,2P) sur sa réactivité avec le méthane ont été réalisées par les techniques de coïncidence TPEPICO et de guides d'ions. Elles ont été réalisées sur la ligne de rayonnement VUV DESIRS du synchrotron SOLEIL. Les études pour déterminer la constante de vitesse et les rapports de branchement entre produits des réactions de N+(3P) avec C3H4, C3H6 et C3H8 ont été réalisées par l'utilisation de la technique SIFT sur un montage de type commercial de petite taille à l'Institut de Physico-Chimie J. Heyrovský à Prague, en République Tchèque.
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Cunha, de Miranda Barbara Kelly. "Estudo da fotoionização de radicais e reações íon-molécula de interesse planetário, através de radiação VUV síncrotron e laser." Thesis, Paris 11, 2011. http://www.theses.fr/2011PA112109/document.

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Ce travail a pour motivation de fournir des données expérimentales importantes pour l'interprétation de la chimie des ionosphère planétaires, en particulier pour le plus grand satellite de Saturne, Titan. On s'intéresse spécifiquement à la réactivité des espèces ioniques excitées. Cette thèse porte, d'une part, sur des expériences de préparation des cations (CH3+ et CF3+) sélectionnés en énergie interne par photoionisation VUV d'espèces neutres, et d'autre part, sur des réactions de cations sélectionnés en énergie interne avec des molécules, O+ avec CH4 et N+(3P) avec C3H4, C3H6 et C3H8.L'étude de la préparation des cations CH3+ et CF3+ sélectionnés dans des niveaux vibrationnels a été réalisée par la technique de coïncidence TPEPICO et du rayonnement VUV synchrotron à SOLEIL. Un spectromètre de type PFI-ZEKE qui permet d'atteindre une résolution de 0.84 cm-1 a été construit pour la réalisation d'études complémentaires avec le rayonnement laser VUV du Centre Laser de l'Université Paris Sud (CLUPS), à Orsay en France.Les expériences pour la détermination de l'influence de l'excitation du cation O+ (2S,2D,2P) sur sa réactivité avec le méthane ont été réalisées par les techniques de coïncidence TPEPICO et de guides d'ions. Elles ont été réalisées sur la ligne de rayonnement VUV DESIRS du synchrotron SOLEIL. Les études pour déterminer la constante de vitesse et les rapports de branchement entre produits des réactions de N+(3P) avec C3H4, C3H6 et C3H8 ont été réalisées par l'utilisation de la technique SIFT sur un montage de type commercial de petite taille à l'Institut de Physico-Chimie J. Heyrovský à Prague, en République Tchèque
This work has the motivation to provide experimental data relevant to the interpretation of the chemistry of planetary ionospheres, particularly for the largest satellite of Saturn, Titan. Here we have a particular interest in studying the reactivity of excited ionic species. The first part of this work concerns the production of CH3+ and CF3+ state selected cations by VUV photoionization of neutral species and the second part, the reactions of state selected cations with molecules: O+ with methane and N+(3P) with C3H4, C3H6 and C3H8.The study of the preparation of the CH3+ and CF3+ cations in selected vibrational levels was performed by using the TPEPICO coincidence technique and VUV radiation at the french synchrotron, SOLEIL. A PFI-ZEKE spectrometer, that allowed us to obtain a resolution down to 0.84 cm-1, was constructed to conduct additional studies involving laser VUV radiation at the Laser Center of the University Paris Sud XI, at Orsay in France.Experiments to determine the influence of the O+ (2S,2D,2P) cation excitation on its reaction with methane were performed using the TPEPICO coincidence and the guide ion beam technique. These experiments were performed on the VUV DESIRS beamline at the synchrotron SOLEIL. Rate constants and products branching ratio for the reacion of N+(3P) with C3H4, C3H6 and C3H8 were measured with the SIFT technique in a small commercial apparatus at the Institute of Physical Chemistry J. Heyrovský in Prague, Czech Republic
Este trabalho tem como motivação fornecer dados experimentais importantes para a interpretação da química de ionosferas planetárias, em particular para o maior Satélite de Saturno, Titan. Aqui temos o interesse específico pelo estudo de reatividades de espécies iônicas excitadas. Uma parte deste trabalho consistiu de experiências de preparação de cátions (CH3+ e CF3+) selecionados em energia interna via a fotoionização VUV de espécies neutras e de reações de cátions selecionados em massa e energia interna com moléculas (O+ com metano e N+(3P) com C3H4, C3H6 e C3H8).O estudo de preparação dos cátions CH3+ e CF3+ selecionados energia interna (vibracional) foi realizado pela utilização da técnica de coincidência TPEPICO com a radiação VUV do síncrotron SOLEIL. Um espectrômetro do tipo PFI-ZEKE que nos permite obter uma resolução de até 0.84 cm-1 foi construído para a realização de estudos complementares envolvendo a radiação VUV laser do Centro de Laser da Universidade Paris Sud XI, em Orsay na França.Experiências para determinar a influência da excitação do cátion O+ (2S,2D,2P) na produção de íons devido a sua reação com o metano foram realizadas com a utilização da técnica de coincidência TPEPICO e da técnica de guia de íons. Estes experimentos foram realizados na linha de radiação VUV DESIRS do síncrotron SOLEIL. Estudos de determinação de constantes de velocidade e dos produtos formados da reação N+(3P) com C3H4, C3H6 e C3H8 foram realizados a partir da utilização da técnica SIFT em uma montagem do tipo comercial de pequeno porte no Instituto de Físico-Química J. Heyrovský em Praga, na República Checa
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Tippayamontri, Thititip. "Simulation Monte-Carlo de la radiolyse du dosimètre de Fricke par des neutrons rapides." Mémoire, Université de Sherbrooke, 2009. http://savoirs.usherbrooke.ca/handle/11143/4013.

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Monte-Carlo calculations are used to simulate the stochastic effects of fast neutron-induced chemical changes in the radiolysis of the ferrous sulfate (Fricke) dosimeter. To study the dependence of the yield of ferric ions, G(Fe[superscript 3+]), on fast neutron energy, we have simulated, at 25 [degree centigrade], the oxidation of ferrous ions in aerated aqueous 0.4 M H[subscript 2]SO[subscript 4] (pH 0.46) solutions when subjected to ~0.5-10 MeV incident neutrons, as a function of time up to ~50 s. The radiation effects due to fast neutrons are estimated on the basis of track segment (or"escape") yields calculated for the first four recoil protons with appropriate weighting according to the energy deposited by each of these protons. For example, a 0.8-MeV neutron generates recoil protons of 0.505, 0.186, 0.069, and 0.025 MeV, with linear energy transfer (LET) values of ~41, 69, 82, and 62 keV/[micro]m, respectively. In doing so, we consider that further recoils make only a negligible contribution to radiation processes. Our results show that the radiolysis of dilute aqueous solutions by fast neutrons produces smaller radical yields and larger molecular yields (relative to the corresponding yields for the radiolysis of water by [superscript 60]Co [gamma]-rays or fast electrons) due to the high LET associated to fast neutrons. The effect of recoil ions of oxygen, which is also taken into account in the calculations, is shown to decrease G(Fe[superscript 3+]) by about 10%. Our calculated values of G(Fe[superscript 3+]) are found to increase slightly with increasing neutron energy over the energy range covered in this study, in good agreement with available experimental data. We have also simulated the effect of temperature on the G(Fe[superscript 3+]) values in the fast neutron radiolysis of the Fricke dosimeter from 25 to 300 [degree centigrade]. Our results show an increase of G(Fe[superscript 3+]) with increasing temperature, which is readily explained by an increase in the yields of free radicals and a decrease in those of molecular products. For 0.8-MeV incident neutrons (the only case for which experimental data are available in the literature), there is a ~23% increase in G(Fe[superscript 3+]) on going from 25 to 300 [degree centigrade]. Although these results are in reasonable agreement with experiment, more experimental data, in particular for different incident neutron energies, would be needed to test more rigorously our Fe[superscript 3+] ion yield results at elevated temperatures.
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Books on the topic "Radical ion pair"

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Books, Prevention Health, ed. Pain-free living for seniors: 355 ways to turn off pain without radical procedures. Emmaus, PA: Rodale, 2001.

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Greene, Alison Collis. Radical Christianity and Cooperative Economics in the Postwar South. University of Illinois Press, 2017. http://dx.doi.org/10.5406/illinois/9780252039997.003.0008.

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This chapter tells a pair of stories—a grassroots beginning and a white backlash sparked by charges of outside agitation—that suggest an all-too-familiar civil rights narrative. Yet, in 1940s North Carolina, two communities—the black farmers and professionals in Tyrrell County and the multiracial network of leftist Protestants who applauded and supported their work—open up a new kind of civil rights story. Theirs is a story of interaction, interdependence, and partnerships built on a shared belief in the inseparability of economic and racial justice. Historians have long emphasized the turn from a Depression-era emphasis on economic and racial justice as two parts of a greater whole to a Cold War-era focus on civil rights and racial integration.
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Dossett, Kate. Radical Black Theatre in the New Deal. University of North Carolina Press, 2020. http://dx.doi.org/10.5149/northcarolina/9781469654423.001.0001.

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Between 1935 and 1939, the United States government paid out-of-work artists to write, act, and stage theatre as part of the Federal Theatre Project (FTP), a New Deal job relief program. In segregated “Negro Units” set up under the FTP, African American artists took on theatre work usually reserved for whites, staged Black versions of “white” classics, and developed radical new dramas. In this fresh history of the FTP Negro Units, Kate Dossett examines what she calls the Black performance community—a broad network of actors, dramatists, audiences, critics, and community activists—who made and remade Black theatre manuscripts for the Negro Units and other theatre companies from New York to Seattle. Tracing how African American playwrights and troupes developed these manuscripts and how they were then contested, revised, and reinterpreted, Dossett argues that these texts constitute an archive of Black agency, and understanding their history allows us to consider Black dramas on their own terms. The cultural and intellectual labor of Black theatre artists was at the heart of radical politics in 1930s America, and their work became an important battleground in a turbulent decade.
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Payne, Russell A., and Kimberly S. Harbaugh. Median Neuropathy—Pronator Teres Syndrome and Anterior Interosseous Neuropathy. Edited by Meghan E. Lark, Nasa Fujihara, and Kevin C. Chung. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780190617127.003.0003.

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Pronator teres syndrome results from median nerve compression or irritation at the elbow region. Patients typically note volar forearm pain and median sensory disturbance that includes the palm. Electrodiagnostic studies are helpful in excluding carpal tunnel syndrome and cervical radiculopathy, and findings may be normal in pronator syndrome. A lack of sensory findings and motor loss in flexion of the distal phalanx of the radial three digits suggests anterior interosseous nerve palsy, typically due to neuralgic amyotrophy. When conservative treatment fails, surgical release of all potential points of compression is successful in alleviating symptoms in the majority of patients with pronator syndrome.
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Smith, Christen A. Afro-Paradise. University of Illinois Press, 2017. http://dx.doi.org/10.5406/illinois/9780252039935.003.0003.

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This chapter analyzes the relationship between carnival and Afro-paradise through two genealogies: racial violence in the national legacy of the use of the black body as an ironic transfer point, a fulcrum for constructing the Brazilian nation, specifically at the site of the pelourinho—the place where enslaved Africans were publically whipped in Brazilian colonial society; and black Brazilians' use of performance (theater and dramatic play) to disrupt and refract this process of violence. For generations, the theater has been a key political space for radical black Brazilians to denounce the myth of racial democracy and declare this myth genocidal. The chapter considers these two interlocking genealogies through a look at race, space, and violence in Bahian carnival, the historical relationship between Afro-paradise and the black body in pain, and the relationship between these two contexts and contemporary black political performance in Salvador.
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Mir, Ali, Saadia Toor, and Raza Mir. Of Race and Religion. Edited by Regine Bendl, Inge Bleijenbergh, Elina Henttonen, and Albert J. Mills. Oxford University Press, 2016. http://dx.doi.org/10.1093/oxfordhb/9780199679805.013.18.

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Prejudice and discrimination in the US against those perceived to be Muslim has reached an all-time high, yet not enough attention has been paid to this phenomenon within the field of management studies. In this chapter, we make the case for why management scholars must address this issue, and do so from within a framework of race and racialization. We show that racism today primarily exists in a cultural form, which is harder to identify and therefore address. Drawing on important insights offered by scholars from various disciplines, we outline the important relationship between religious, and specifically anti-Muslim, prejudice in the West and the origins and evolution of the idea of race. The racialization of Muslims today draws on this history and the various discourses of race so as to construct ‘the Muslim’ as the radical Other of a liberal and progressive West.
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Hansen, Helena. Addicted to Christ. University of California Press, 2018. http://dx.doi.org/10.1525/california/9780520298033.001.0001.

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How are spiritual power and self-transformation cultivated in street ministries? This book provides an in-depth analysis of Pentecostal ministries in Puerto Rico that were founded and run by self-identified “ex-addicts,” ministries that are also widespread in poor Black and Latino neighborhoods in the U.S. mainland. The book melds cultural anthropology and psychiatry. Through the stories of ministry converts, the book examines key elements of Pentecostalism: mysticism, ascetic practice, and the idea of other-worldliness. It then reconstructs the ministries' strategies of spiritual victory over addiction: transformation techniques to build spiritual strength and authority through pain and discipline; cultivation of alternative masculinities based on male converts' reclamation of domestic space; and radical rupture from a post-industrial “culture of disposability.” By contrasting the ministries' logic of addiction with that of biomedicine, the book rethinks roads to recovery, discovering unexpected convergences with biomedicine while revealing the allure of street corner ministries.
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Shaibani, Aziz. Distal Arm Weakness. Oxford University Press, 2015. http://dx.doi.org/10.1093/med/9780199898152.003.0015.

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Distal arm weakness may be caused by involvement of the intrinsic hand muscles (interossi, thenar and hypothenar muscles, lumbricals) or extrinsic hand muscles (long finger flexors and extensors). ALS is typical for the former type, and IBM is typical for the latter type. Incoordination of skilled finger movement due to cerebellar disease is associated with normal strength. Poor mobility due to joints pain and swelling should not be confused with muscle weakness. Mononeuropathies such as ulnar, radial, median, and AIN,lesions usually cause differential loss of function. Myasthenia sometimes causes weakness of the wrist and finger extensors. A small but distinct group of distal hereditary myopathies should always be borne in mind. Progressive sensorimotor neuropathies are usually associated with sensory symptoms. Multifocal motor neuropathy can be a diagnostic challenge.
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Brandth, Berit, and Elin Kvande. Designing Parental Leave Policy. Policy Press, 2020. http://dx.doi.org/10.1332/policypress/9781529201574.001.0001.

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Many of the Nordic countries have designed parental leave policies in ways that can promote participation of fathers in child care. Norway was the first country to introduce a father-specific leave quota in 1993. This quota is non-transferable and generously paid, and Norway has functioned as a sort of laboratory for testing such radical policies. This book is a collection of research publications from three studies conducted at various stages since the introduction of the quota. It looks at its various design characteristics and possible consequences such as take-up, framing of the leave, what fathers do when on leave, how they develop as caregivers and competent parents, how working life relates to male employees with care obligations in terms of parental leave, how fathers adapt their leave to work and how immigrant fathers relate to the laws and expectations directed to fathers in Norway. Although the chapters are based on different qualitative studies, they show changes in employed men’s fathering practices over the years and how the parental leave design may have contributed to this change.
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Sloman, Peter. Transfer State. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198813262.001.0001.

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The idea of a guaranteed minimum income has been central to British social policy debates for more than a century. Since the First World War, a variety of market economists, radical activists, and social reformers have emphasized the possibility of tackling poverty through direct cash transfers between the state and its citizens. As manufacturing employment has declined and wage inequality has grown since the 1970s, cash benefits and tax credits have become a major income source for millions of working-age households, including many low-paid workers with children. The nature and purpose of these transfer payments, however, remain highly contested. Conservative and New Labour governments have used in-work benefits and conditionality requirements to ‘activate’ the unemployed and reinforce the incentives to take low-paid work—an approach which has reached its apogee in Universal Credit. By contrast, a growing number of campaigners have argued that the challenge of providing economic security in an age of automation would be better met by paying a Universal Basic Income to all citizens. Transfer State provides the first detailed history of guaranteed income proposals in modern Britain, which brings together intellectual history and archival research to show how the vision of an integrated tax and benefit system has shaped UK public policy since 1918. The result is a major new analysis of the role of cash transfers in the British welfare state which sets Universal Credit in a historical perspective and examines the cultural and political barriers to a Universal Basic Income.
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Book chapters on the topic "Radical ion pair"

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Lersch, W., E. Lang, R. Feick, W. J. Coleman, D. C. Youvan, and M. E. Michel-Beyerle. "Determination of the Exchange Interaction in the Primary Radical Ion Pair in Reaction Centers." In The Jerusalem Symposia on Quantum Chemistry and Biochemistry, 81–90. Dordrecht: Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-0489-7_8.

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Wasielewski, M. R., G. L. Gaines, M. P. O’Neil, W. A. Svec, M. P. Niemczyk, and D. M. Tiede. "Multi-Step Electron Transfer in Rigid Photo-synthetic Models at Low Temperature: Requirements for Charge Separation and Spin-Polarized Radical Ion Pair Formation." In Reaction Centers of Photosynthetic Bacteria, 349–57. Berlin, Heidelberg: Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-642-61297-8_34.

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Staerk, H., R. Treichel, and A. Weller. "Polymethylene-Linked Radical Ion Pairs in Magnetic Fields." In Springer Proceedings in Physics, 85–89. Berlin, Heidelberg: Springer Berlin Heidelberg, 1986. http://dx.doi.org/10.1007/978-3-642-71526-6_14.

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Peters, Kevin S. "Diffusional Quenching of trans-Stilbene by Fumaronitrile: Role of Contact Radical Ion Pairs and Solvent Separated Radical Ion Pairs." In Ultrafast Dynamics of Chemical Systems, 223–33. Dordrecht: Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-011-0916-1_7.

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Warren, Timothy H., and Gerhard Erker. "Radical Frustrated Lewis Pairs." In Topics in Current Chemistry, 219–38. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/128_2012_390.

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Mattay, Jochen, and Martin Vondenhof. "Contact and solvent-separated radical ion pairs in organic photochemistry." In Topics in Current Chemistry, 219–55. Berlin, Heidelberg: Springer Berlin Heidelberg, 1991. http://dx.doi.org/10.1007/3-540-53257-9_5.

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Porter, N. A., and P. J. Krebs. "Stereochemical Aspects of Radical Pair Reactions." In Topics in Stereochemistry, 97–127. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2007. http://dx.doi.org/10.1002/9780470147276.ch2.

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Lewis, Alan. "Introduction." In Spin Dynamics in Radical Pairs, 1–17. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-030-00686-0_1.

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Lewis, Alan. "Quantum Mechanics." In Spin Dynamics in Radical Pairs, 19–43. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-030-00686-0_2.

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Lewis, Alan. "Semiclassical Approximations." In Spin Dynamics in Radical Pairs, 45–63. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-030-00686-0_3.

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Conference papers on the topic "Radical ion pair"

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PINCOCK, J. A., S. RIFAI, and R. STEFANOVA. "INTRAMOLECULAR RADICAL ION PAIRS IN THE PHOTOCHEMISTRY OF 2-ARYLETHYL ESTERS." In Proceedings of the 10th Annual Symposium of the NSF Center. WORLD SCIENTIFIC, 2000. http://dx.doi.org/10.1142/9789812793294_0003.

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Schubring, DuWayne, Rory E. Foster, and Timothy A. Shedd. "Two-Zone PIV Analysis of Wavy and Wavy-Annular Two-Phase Flow." In 16th International Conference on Nuclear Engineering. ASMEDC, 2008. http://dx.doi.org/10.1115/icone16-48111.

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Cross-sectional thin film micro-particle image velocimetry (cTFMPIV) analysis has been performed for air-water two-phase flow in a 19.05 mm horizontal duct. Images were captured by introducing a light sheet from a Nd:YAG laser into the flow, with the fluorescent emissions from three micron particles captured by a CCD camera behind a microscope objective and red filter. These images were grouped into pairs and digitally enhanced to isolate particle traces using commercial image processing software. Image pairs were collected for five air flow rates at each of four water flow rates and separated into base film and wave zones for PIV analysis. Using DaVis 7.1 (LaVision GmbH), vector maps were obtained for each pair. Less than 2% of the image pairs were removed due to clearly spurious vectors, while the appropriate zone for less than 8% of the image pairs could not be determined These pairs were grouped into a third batch. The vector maps were analyzed to calculate velocity profiles and turbulence (fluctuation) statistics in terms of wall coordinates. These statistics included intensities and Reynolds stresses. The base film shows laminar behavior beyond what would be expected from the universal velocity profile. The wave zone displays significantly different behavior and appears to reach an asymptote rapidly. Calculation of fluctuation intensities indicates a maximum within the wave zone along the gas-liquid interface, while the distribution of radial fluctuations in the base film and axial turbulence in all zones is approximately uniform. Calculation of the u′v′ shear Reynolds stress suggests that it has a negative value.
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Simpson, Alister, Stephen W. T. Spence, and Juliana Early. "A Numerical and Experimental Study of the Rotor Inlet Flow Fields of Radial Turbines Using Vaned and Vaneless Stators." In ASME Turbo Expo 2009: Power for Land, Sea, and Air. ASMEDC, 2009. http://dx.doi.org/10.1115/gt2009-59998.

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This paper describes experimental and numerical investigations of the flow fields delivered to the inlet of a radial turbine rotor by vaned and vaneless stators, and to what extent they influence the stage performance. The work focussed on the flow fields delivered to the inlet of an 86mm turbine by 3 pairs of vaned and vaneless housings, each pair having matching flow capacities. Static pressure measurements at rotor inlet were acquired, and from these the circumferential flow distributions at rotor inlet were directly compared. The experimental results were used to validate numerical models to study the rotor inlet flow fields in greater detail. Both numerical and experimental results highlighted the vaneless stators to deliver a higher level of uniformity at rotor inlet. The comparatively higher levels of non-uniformity in the vaned stator builds can be primarily attributed to jet and wake effects, as these were found not to have mixed out significantly at the rotor inlet and contributed both to the overall levels of pressure loss and higher variations of rotor inlet incidence. Comparisons have been made to previously reported turbine performance data, and the influence of the rotor inlet flow field on stage running performance has been discussed.
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Wang, Shijie, and Guang Hong. "Innovative Design of a Thrust-Eccentric Gear Coupling for Submerged-Motor-Driven PC Pumping System." In ASME 2001 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/detc2001/dac-21140.

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Abstract The gear coupling, which transmits axial compressive force, torque and relative eccentric motion, is the key component of progressing cavity (PC) pumping systems. This paper reports an innovative design of such a gear coupling especially used for submerged-motor-driven PC pumping system applied in oil fields. The novelty of this design is the synergy of a zero-tooth-difference internal meshing gear pair and a spherical pair. The principle of transmission and the determination of the key parameters such as the tangential and radial modification factors are described in this paper. Considering the reduced thickness of the gear tooth and the harsh operating condition of the PC pumping system, verification for the contacting and bending fatigue strength of the zero-tooth-difference gear pair is recommended, and the corresponding method is discussed.
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Mansour, M., N. Chokani, A. I. Kalfas, and R. S. Abhari. "Unsteady Entropy Measurements in a High-Speed Radial Compressor." In ASME Turbo Expo 2007: Power for Land, Sea, and Air. ASMEDC, 2007. http://dx.doi.org/10.1115/gt2007-27450.

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The time-dependent relative entropy field at the impeller exit of a centrifugal compressor is measured. This study is part of a broader effort to develop comprehensive measurement techniques that can be applied in the harsh environment of turbomachines. A miniature unsteady entropy probe (diameter 1.8mm) is designed and constructed in the present study. The unsteady entropy probe has two components: a one-sensor fast response aerodynamic probe and a pair of thin-film gauges. The time-dependent total pressure and total temperature are measured from the fast response aerodynamic probe and pair of thin-film gauges, respectively. The time-dependent relative entropy derived from these two measurements has a bandwidth of 40kHz and uncertainty of ±2J/kg. The measurements show that at the near design operating condition, the impeller exit flowfield is highly three-dimensional. Adjacent to the shroud there are high levels of relative entropy and at the mid-span there are low & moderate levels. Independent measurements made with a two-sensor aerodynamic probe show that the high velocity of the flow relative to the casing is responsible for the high relative entropy levels at the shroud. On the otherhand, at the mid-span, a loss free, jet flow region and a channel wake flow of moderate mixing characterize the flowfield. At both the shroud and mid-span, there are strong circumferential variations in the relative entropy. These circumferential variations are much reduced when the centrifugal compressor is operated near the onset of stall. In this condition the impeller exit flowfield is less highly skewed; however, the time-averaged relative entropy is higher than at the near design operating condition. The relative entropy measurements with the unsteady entropy probe are thus complementary to other measurements, and more clearly document the losses in the centrifugal compressor.
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Bohn, Dieter, Jing Ren, and Christian Tuemmers. "Investigation of the Unstable Flow Structure in a Rotating Cavity." In ASME Turbo Expo 2006: Power for Land, Sea, and Air. ASMEDC, 2006. http://dx.doi.org/10.1115/gt2006-90494.

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Annular cavities are found inside rotor shafts of turbomachines with an axial or radial throughflow of cooling air, which influences the thermal efficiency and system reliability of the gas turbines. The flow and heat transfer phenomena in those cavities should be investigated in order to minimize the thermal load and guarantee system reliability. An experimental rig is set up in the Institute of Steam and Gas Turbines to analyze the flow structure inside the rotating cavity with an axial throughflow of cooling air. The corresponding 3D numerical investigation is carried out with the in-house fluid solver CHTflow, in which the Coriolis force and the buoyancy force are implemented in the time-dependent Navier-Stokes equations. Both the experimental and numerical results show the whole flow structure rotating against the cavity rotating direction. The flow passing the observation windows shows the quite similar trajectories in the experimental and numerical results. The computed sequences and periods of the vortex flow structure correspond closely with those observed in the experiment. Furthermore, the numerical analysis reveals a flow pattern changing between single pair, double pairs and triple pairs vortices. It is suggested that the vortices inside the cavity are created by the gravitational buoyancy force in the investigated case, and the number and strength of the vortices are controlled mainly by the Coriolis force.
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Anand, Sam, Sridhar Jaganathan, and Sampath Damodarasamy. "An Efficient Algorithm for Accurate Evaluation of Circularity Tolerance." In ASME 1996 Design Engineering Technical Conferences and Computers in Engineering Conference. American Society of Mechanical Engineers, 1996. http://dx.doi.org/10.1115/96-detc/fas-1366.

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Abstract This paper presents a new and accurate algorithm for assessing circularity tolerance from a set of data points obtained from a Coordinate Measuring Machine (CMM). This method, called Selective Zone Search algorithm, divides the workspace into small sectors called search zones and searches for the extreme points in these zones. These extreme points are used to draw a pair of concentric circles with minimum radial separation. The radial difference gives the circularity. The methodology has been tested with several example data sets and the results have been compared with the Least Squares method, Minimum Spanning Circle method and the Voronoi Diagram method.
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Groot, Marie-Louise, Lars-Olof Pålsson, Radmila Pribic, Ivo H. van Stokkum, Jan P. Dekker, and Rienk van Grondelle. "Energetics and excited state dynamics of the radical pair formation in isolated CP47-reaction center complex of photosystem II at various temperatures." In The 54th international meeting of physical chemistry: Fast elementary processes in chemical and biological systems. AIP, 1996. http://dx.doi.org/10.1063/1.50205.

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Ren, Zhaohui, Said Jahanmir, Hooshang Heshmat, and James Walton. "Hybrid Magnetic Bearings for a Centrifugal Blood Pump." In ASME/STLE 2007 International Joint Tribology Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/ijtc2007-44199.

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Abstract:
A hybrid passive/active magnetic bearing system was designed for a rotary centrifugal blood pump being developed for long-term circulatory support for heart failure patients. This system consists of two axially spaced bearing combinations for complete magnetic levitation of the rotor using only a single-axis active control. Each bearing combination comprises a pair of axially oppositely polarized permanent magnet rings on the rotor and a similar pair in the stator housing for both radial support and axial bias flux, and an electromagnetic coil to actively control the rotor axial position. The design permits a relatively large radial clearance between rotor and stator, and provides sufficient radial/axial stiffness, active controllability over the desired axial travel of the rotor. The bearing characteristics were evaluated by electromagnetic finite element analysis. The prototype pump was fabricated and levitated using a PID controller with zero-force balance algorithm to stabilize the rotor in the thrust direction and minimize the power draw. The experimental results confirmed the efficacy of the proposed magnetic bearing design and associated control algorithm.
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Mohamed-Kassim, Zulfaa, and Ellen K. Longmire. "Experiments on Drop Impact and Coalescence at a Liquid/Liquid Interface." In ASME/JSME 2003 4th Joint Fluids Summer Engineering Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/fedsm2003-45150.

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The gravity-driven impact and coalescence of a single drop through a liquid/liquid interface have been investigated experimentally. PIV images were obtained with a high frequency pulsed-laser and a high-speed video camera. Index-matching and a slight camera inclination were employed to eliminate optical distortion. The drop Reynolds numbers based on impact velocity and ambient viscosity were 20 and 68. During the approach towards the interface, viscous stresses generated a vortex ring inside each drop and a wake behind it. The subsequent deformation of the drop and the interface due to impact were observed to be more radical in the higher Re case. Both the wake shearing on the upper drop surface and interfacial deformation were significant in dissipating the vorticity inside the drops. After the vorticity dissipated, an outward flow developed along one radian between the ‘resting’ drop and the interface below generating a counter-rotating vortex pair. The eventual coalescence was typically off axis. During coalescence, a capillary ring wave propagated radially inward enhancing the collapse of the drop fluid into the bulk liquid below.
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Reports on the topic "Radical ion pair"

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Wen, X., K. G. Spears, G. P. Wiederrecht, and M. R. Wasielewski. Electron transfer of carbonylmetalate radical pairs: femtosecond visible spectroscopy of optically excited ion pairs. Office of Scientific and Technical Information (OSTI), February 1997. http://dx.doi.org/10.2172/488804.

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