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Littérature scientifique sur le sujet « Ion chemistry and composition »

Auteur : Grafiati

Publié le 10 mars 2023

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Articles de revues sur le sujet "Ion chemistry and composition"

Ip, W. H. « Ion composition and chemistry ». Advances in Space Research 9, n^o 3 (1989) : 141–50. http://dx.doi.org/10.1016/0273-1177(89)90253-6.

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Breig, E. L. « Thermospheric ion and neutral composition and chemistry ». Reviews of Geophysics 25, n^o 3 (1987) : 455. http://dx.doi.org/10.1029/rg025i003p00455.

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Vuitton, V., R. V. Yelle et P. Lavvas. « Composition and chemistry of Titan's thermosphere and ionosphere ». Philosophical Transactions of the Royal Society A : Mathematical, Physical and Engineering Sciences 367, n^o 1889 (20 novembre 2008) : 729–41. http://dx.doi.org/10.1098/rsta.2008.0233.

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Titan has long been known to harbour the richest atmospheric chemistry in the Solar System. Until recently, it had been believed that complex hydrocarbons and nitriles were produced through neutral chemistry that would eventually lead to the formation of micrometre sized organic aerosols. However, recent measurements by the Cassini spacecraft are drastically changing our understanding of Titan's chemistry. The Ion and Neutral Mass Spectrometer (INMS) and the Cassini Plasma Spectrometer (CAPS) revealed an extraordinary complex ionospheric composition. INMS detected roughly 50 positive ions with m / z <100 and a density higher than 0.1 cm −3 . CAPS provided evidence for heavy (up to 350 amu) positively and negatively charged (up to 4000 amu) ions. These observations all indicate that Titan's ionospheric chemistry is incredibly complex and that molecular growth starts in the upper atmosphere rather than at lower altitude. Here, we review the recent progress made on ionospheric chemistry. The presence of heavy neutrals in the upper atmosphere has been inferred as a direct consequence of the presence of complex positive ions. Benzene (C 6 H 6 ) is created by ion chemistry at high altitudes and its main photolysis product, the phenyl radical (C 6 H 5 ), is at the origin of the formation of aromatic species at lower altitude.

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Zhao, Chenglong, Qidi Wang, Zhenpeng Yao, Jianlin Wang, Benjamín Sánchez-Lengeling, Feixiang Ding, Xingguo Qi et al. « Rational design of layered oxide materials for sodium-ion batteries ». Science 370, n^o 6517 (5 novembre 2020) : 708–11. http://dx.doi.org/10.1126/science.aay9972.

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Sodium-ion batteries have captured widespread attention for grid-scale energy storage owing to the natural abundance of sodium. The performance of such batteries is limited by available electrode materials, especially for sodium-ion layered oxides, motivating the exploration of high compositional diversity. How the composition determines the structural chemistry is decisive for the electrochemical performance but very challenging to predict, especially for complex compositions. We introduce the “cationic potential” that captures the key interactions of layered materials and makes it possible to predict the stacking structures. This is demonstrated through the rational design and preparation of layered electrode materials with improved performance. As the stacking structure determines the functional properties, this methodology offers a solution toward the design of alkali metal layered oxides.

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Feistel, Rainer. « On the Physical Chemistry of Seawater with Deviating Ion Composition ». Zeitschrift für Physikalische Chemie 204, Part_1_2 (janvier 1998) : 27–44. http://dx.doi.org/10.1524/zpch.1998.204.part_1_2.027.

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Johnston, Kathryn A., Lisa M. Stabryla, Ashley M. Smith, Xing Yee Gan, Leanne M. Gilbertson et Jill E. Millstone. « Impacts of broth chemistry on silver ion release, surface chemistry composition, and bacterial cytotoxicity of silver nanoparticles ». Environmental Science : Nano 5, n^o 2 (2018) : 304–12. http://dx.doi.org/10.1039/c7en00974g.

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We determine the impact of bacterial growth media on silver nanoparticle surface chemistry, this surface chemistry on silver ion release from the nanoparticles, and ultimately the antimicrobial implications of those parameters.

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Vigren, Erik. « Analytic model of comet ionosphere chemistry ». Astronomy & ; Astrophysics 616 (août 2018) : A59. http://dx.doi.org/10.1051/0004-6361/201832704.

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Context. We consider a weakly to moderately active comet and make the following simplifying assumptions: (i) The partial ionization frequencies are constant throughout the considered part of the coma. (ii) All species move radially outward with the same constant speed. (iii) Ion-neutral reactions affect the chemical composition of the ions, but ion removal through dissociative recombination with free electrons is negligible. Aims. We aim to derive an analytical model for the radial variation of the abundances of various cometary ions. Methods. We present two methods for retrieving the ion composition as a function of r. The first method, which has previously been used frequently, solves a series of coupled differential equations. The new method introduced here is based on probabilistic arguments and is analytical in nature. Results. For a pure H2O coma, the resulting closed-form expressions yield results that are identical to the standard method, but are computationally much less expensive. Conclusions. In addition to the computational simplicity, the analytical model provides insight into how the various abundances depend on parameters such as comet production rate, outflow speed, and reaction rate coefficients. It can also be used to investigate limiting cases. It cannot easily be extended to account for a radially varying flow speed or dissociative recombination in the way a code based on numerical integrations can.

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Verronen, P. T., E. Turunen, Th Ulich et E. Kyrölä. « Modelling the effects of the October 1989 solar proton event on mesospheric odd nitrogen using a detailed ion and neutral chemistry model ». Annales Geophysicae 20, n^o 12 (31 décembre 2002) : 1967–76. http://dx.doi.org/10.5194/angeo-20-1967-2002.

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Abstract. Solar proton events and electron precipitation affect the concentrations of middle atmospheric constituents. Ionization caused by precipitating particles enhances the production of important minor neutral constituents, such as nitric oxide, through reaction chains in which ionic reactions play an important role. The Sodankylä Ion Chemistry model (SIC) has been modified and extended into a detailed ion and neutral chemistry model of the mesosphere. Our steady-state model (containing 55 ion species, 8 neutral species, and several hundred chemical reactions) is used to investigate the effect of the October 1989 solar proton event on odd nitrogen at altitudes between 50–90 km. The modelling results show that the NO concentration is significantly enhanced due to the proton precipitation, reaching 107 –108 cm-3 throughout the mesosphere on the 20 October when the proton forcing was most severe. A comparison between the chemical production channels of odd nitrogen indicates that ion chemical reactions are an important factor in the total odd nitrogen production during intense ionization. The modelled electron concentration for the 23 October is compared with EISCAT incoherent scatter radar measurements and a reasonable agreement is found.Key words. Atmospheric composition and structure (Middle atmosphere – composition and chemistry); Ionosphere (Particle precipitation)

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Litvin, A., W. Kofman et B. Cabrit. « Ion composition measurements and modelling at altitudes from 140 to 350 km using EISCAT measurements ». Annales Geophysicae 16, n^o 10 (31 octobre 1998) : 1159–68. http://dx.doi.org/10.1007/s00585-998-1159-6.

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Abstract. This work aims at processing the data of CP1 and CP2 programs of EISCAT ionospheric radar from 1987 to 1994 using the "full profile" method which allows to solve the "temperature-composition" ambiguity problem in the lower F region. The program of data analysis was developed in the CEPHAG in 1995–1996. To improve this program, we implemented another analytical function to model the ion composition profile. This new function better reflects the real profile of the composition. Secondly, we chose the best method to select the initial conditions for the "full profile" procedure. A statistical analysis of the results was made to obtain the averages of various parameters: electron concentration and temperature, ion temperature, composition and bulk velocity. The aim is to obtain models of the parameter behaviour defining the ion composition profiles : z50 (transition altitude between atomic and molecular ions) and dz (width of the profile), for various seasons and for high and low solar activities. These models are then compared to other models. To explain the principal features of parameters z50 and dz, we made an analysis of the processes leading to composition changes and related them to production and electron density profile. A new experimental model of ion composition is now available.Key words. Auroral ionosphere · Ion chemistry and composition · Instruments and techniques · EISCAT

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Kalakoski, Niilo, Pekka T. Verronen, Annika Seppälä, Monika E. Szeląg, Antti Kero et Daniel R. Marsh. « Statistical response of middle atmosphere composition to solar proton events in WACCM-D simulations : the importance of lower ionospheric chemistry ». Atmospheric Chemistry and Physics 20, n^o 14 (28 juillet 2020) : 8923–38. http://dx.doi.org/10.5194/acp-20-8923-2020.

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Abstract. Atmospheric effects of solar proton events (SPEs) have been studied for decades, because their drastic impact can be used to test our understanding of upper stratospheric and mesospheric chemistry in the polar cap regions. For example, odd hydrogen and odd nitrogen are produced during SPEs, which leads to depletion of ozone in catalytic reactions, such that the effects are easily observed from satellites during the strongest events. Until recently, the complexity of the ion chemistry in the lower ionosphere (i.e., in the D region) has restricted global models to simplified parameterizations of chemical impacts induced by energetic particle precipitation (EPP). Because of this restriction, global models have been unable to correctly reproduce some important effects, such as the increase in mesospheric HNO3 or the changes in chlorine species. Here we use simulations from the WACCM-D model, a variant of the Whole Atmosphere Community Climate Model, to study the statistical response of the atmosphere to the 66 strongest SPEs which occurred in the years 1989–2012. Our model includes a set of D-region ion chemistry, designed for a detailed representation of the atmospheric effects of SPEs and EPP in general. We use superposed epoch analysis to study changes in O3, HOx (OH + HO2), Clx (Cl + ClO), HNO3, NOx (NO + NO2) and H2O. Compared to the standard WACCM which uses an ion chemistry parameterization, WACCM-D produces a larger response in O3 and NOx and a weaker response in HOx and introduces changes in HNO3 and Clx. These differences between WACCM and WACCM-D highlight the importance of including ion chemistry reactions in models used to study EPP.

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Thèses sur le sujet "Ion chemistry and composition"

Wronska, Louisa Victoria May. « The factors & ; protocols that influence accuracy, precision & ; uncertainty of accurate mass measurements by Fourier transform ion cyclotron resonance mass spectrometry to validate the assignment of elemental composition ». Thesis, University of Southampton, 2009. https://eprints.soton.ac.uk/67059/.

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The need for very accurate mass measurements of compounds is becoming more demanding with the expansion of the number of compounds in need of correct identification and with the limits of elemental analysis; a fast, robust analytical solution is sought. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) is a very powerful tool for undertaking accurate mass measurements because of its high resolving power and mass accuracy. The use of FT-ICR MS in a high-throughput environment is limited due to the need of operator intervention required to obtain optimum accurate mass measurements. The lowest mass measurement errors (MME) are usually obtained using internal calibration, as the sample and calibrant ions inside the ICR cell experience the same conditions. However, internal calibration requires calibrant ions to be selected according to the mass of the sample ion, which requires operator intervention. External calibration is the preferred choice when performing accurate mass measurements in a high-throughput environment, as a calibration can be acquired independently of the sample. This study aims to demonstrate the use of ion population balancing using a dual sprayer approach to reduce MME. Population balancing between sample ions and calibrant ions can reduce the MME 40-fold. Ion populations across a chromatographic run can also vary greatly. The dual sprayer can also be employed to easily control the ion populations of both sample and calibrant entering the cell and can help to reduce ion suppression. The aim of the latter part of the work was to address the uncertainty of an accurate mass measurement performed using FT-ICR MS. In order to confidently select an elemental formula following an accurate mass measurement, a ‘cut-off’ limit or tolerance has to be selected. This tolerance can be set by calculating the uncertainty of the measurement; without an uncertainty component the measurement is meaningless. The work herein demonstrates how to calculate uncertainty of an accurate mass measurement with the aim that journals will adopt a procedure of only accepting an accurate mass measurement which quotes an uncertainty.

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Martin, Riana Theresa. « Evaluation of capillary electrophoresis as an analytical technique using bulk ionic composition of fluid inclusions in quartz ». Thesis, Stellenbosch : Stellenbosch University, 2000. http://hdl.handle.net/10019.1/51751.

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Thesis (MSc)--Stellenbosch University, 2000.
ENGLISH ABSTRACT: This study was initialized to introduce capillary electrophoresis (CE) as a useful technique in the analysis of fluid inclusions in quartz. lts advantages are low detection limits for the dissolved ionic content of the fluid, the small amount of sample (1 g or less) for a detailed qualitative and quantitative analysis, and the short time required to obtain results (one run for either cations or anions take approximately 10 minutes). The study area from which quartz veins were selected is situated within the Neoproterozoic Saldania belt. Syn- and post-tectonic S-, 1- and A-type granitoids from the Cape Granite Suite intruded the metamorphosed Malmesbury greywacke and pelites between 550 and 510 Ma. Additional periods of tectonism and metamorphism occurred during Cape Supergroup sedimentation (480 - 400 Ma) as well as Karoo sedimentation and the simultaneous Cape Orogeny (280 -215 Ma). The quartz-biotite±chlorite vems are hosted by Cape Granite as well as Malmesbury sediments. These barren quartz veins are part of two vein sets, one dipping at an angle between 15 and 500 to the S to SE and striking W, similar to Sn-mineralized quartz veins in the SW-cape, while the other is near-vertical and striking W to NW. Except for their orientation, no differences regarding associated minerals, inclusion characteristics or fluid chemistry indicated a difference in origin. Four fluid phases within a temperature range of 160 - 390 °C were identified as being largely late-magmatic and released from the underlying Cape Granite plutons, namely an early 370- 390 °C population, followed by the 310 - 360, 230 - 300 and lastly the 160 - 200 °C populations. Initiation of this fluid system occurred from at least SlOMa, after final granite intrusion, but the age of the final stage is unknown. Renewed fluid circulation occurred during a later period of metamorphism, possibly during the Cape Orogeny. These fluids had temperatures between 240 and 360°C and are of sedimentary origin, most likely released from the Malmesbury metamorphites. The technique of capillary electrophoresis has been evaluated for its application to bulk fluid inclusion analysis, and the crush-leach fluid extraction procedure of Bottrell, et al., (1988) optimized for CE analysis. Contamination factors were identified and minimized or eliminated, where possible. Bulk fluid inclusion chemistry obtained by CE was therefore proved to provide valuable information regarding the various fluid generations as long as inclusion populations are investigated individually to explain and correlate bulk data.
AFRIKAANSE OPSOMMING: Die doel van die studie was om te toon dat die tegniek van kapillêre elektroforese bruikbaar is in die analiese van vloeistofmsluitsels in kwarts. Die voordele van hierdie tegniek is lae deteksie limiete vir die opgeloste ioon inhoud van die vloeistof, die klein monstergrootte (< 1g) wat nodig is vir 'n omvattende kwalitatiewe en kwantitatiewe analise, en die kort tydsduur waarin resultate verkry word ('n katioon of anioon analise vir een monster duur lO minute). Die studie gebied waar kwarts are gemonster is, is binne die Neoproterosoïese Saldania Gordel geleë. Sin- en laat-tektoniese S-, I- en A-tipe graniete van die Kaapse Graniet Suite het die gemetamorfiseerde Malmesbury grouwakke en peliete tussen 550 en 510 Ma binnegedring. Latere periodes van tektonisme en metamorfose het tydens deponering van die Kaap Supergroep (480 - 400 Ma), en die gelyktydige episodes van Karoo sedimentasie en Kaapse Orogenese (280 - 215 Ma) plaasgevind. Die gasheer gesteentes vir die kwarts-biotiet±chloriet are is Kaapse Graniet sowel as Malmesbury sedimente. Hierdie ongemineraliseerde are is deel van twee aarstelsels, nl. een met 'n duik hoek tussen 15 en 50° S tot SO en 'n westelike strekking, soortgelyk aan die Sn- ,.gemineraliseerde are in die SW-Kaap, terwyl die ander stel are feitlik vertikaal is en W tot NW strek. Behalwe vir die verskil in oriëntasie was daar geen aanduiding, wat betref 'n verskil in geassosieerde minerale, vloeistofinsluitsel kenmerke of vloeistof chemie, dat hierdie twee aarstelsels van verskillende oorsprong is nie. Vier vloeistof fases binne 'n temperatuur gebied van 160 - 390 °C en 'n vloeistof saliniteit van 0 - 5.7 gewig % NaC1 ekw. is geïdentifiseer, met 'n laat-magmatiese assosiasie en vrygestel deur die onderliggende Kaapse Graniete. Dit behels 'n vroeë 370 - 390 °C populasie, gevolg deur die 310 - 360, 230 - 300 en laastens die 160 - 200 °C populasies. Inisiasie van hierdie sisteem kon moontlik rondom 510 Ma gelede plaasgevind het, maar die ouderdom van die finale fase is onbekend. Hernude vloeistof sirkulasie het tydens 'n later stadium van metamorfose onstaan, moontlik tydens die Kaapse Orogenese. Hierdie vloeistowwe het temperature tussen 240 en 360 °C en is van sedimentêre oorsprong waar dit moontlik deur metamorfose van die reeds gemetamorfiseerde Malmesbury gesteentes vrygestel is. Die tegniek van kapillêre elektroforese is vir die toepassing daarvan in die analise van vloeistof insluitsels in kwarts geëvalueer, terwyl die vloeistof vrystellingsmetode van Bottrell en Yardley (1988) vir hierdie tegniek geoptimaliseer is. Kontaminasie faktore is geïdentifiseer en verminder of uitgeskakel waar moontlik. Daar is getoon dat die vloeistof chemie, wat verteenwoordigend is van al die insluitsel populasies in 'n monster, wel bruikbaar is t.o.v. afsonderlike vloeistof generasies, solank elke populasie individueel bestudeer is om die omvattende chemiese data te verduidelik en met 'n enkele populasie te korrelleer.

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Toida, Mieko, Hiroyuki Higashino et Yukiharu Ohsawa. « Effect of ion composition on ion acceleration by magnetosonic shock waves ». American Institite of Physics, 2008. http://hdl.handle.net/2237/12029.

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Isildak, Ibrahim. « Ion selective electrodes in ion chromatography ». Thesis, University of Newcastle Upon Tyne, 1992. http://hdl.handle.net/10443/859.

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The number of applications of potentiometric detection In Ion chromatography Is Increasing In the use of ion selective electrodes for which the response Is not limited to a few number of Ions. In this research, membrane electrodes, for a number of Ions, based on PVC were prepared to examine selectivity, detection limit and reproducibility for chromatographic and flow-injection measurements via mixed solution method and flow-injection technique. The selectivity sequence of anion selective electrodes for single charged Inorganic anions was F< Cl < Br < NO 2< NO 3

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Bissonnette, Martine C. « Ion/radical and ion/molecule complexes and ion structure assignments in the gas phase ». Thesis, University of Ottawa (Canada), 1991. http://hdl.handle.net/10393/7731.

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The fragmentation mechanism of ionized neopentanol, (CH$\sb3$)$\sb3$CCH$\sb2$OH$\sp{+-}$, has been studied in great detail along with other C$\sb5$H$\sb $H$\sp{+-}$ isomers. The use of $\sp $C and D labelling was found an essential tool to establish the relation between the other species involved in the dissociation of neopentanol. The involvement of (CH$\sb3$)$\sb2$C$\sp{\cdot}$CH$\sb2\sp+$(O)HCH$\sb3$, (CH$\sb3$)$\sb3$C$\sp+$(O)HCH$\sb2$ and (CH$\sb3$)$\sb2$($\sp\cdot$CH$\sb2$)CCH$\sb2\sp+$OH$\sb2$ was essential to explain the H/D label exchange occurring upon fragmentation of neopentyl alcohol. An ion-dipole complex between methanol and ionized methyl propene is proposed as the final intermediate which leads directly to the products, methanol and ionized methyl propene. The results of the investigation of C$\sb7$H$\sb5\sp+$ ions from various precursor molecules are also described. The following compounds, which all produce C$\sb7$H$\sb5\sp+$ ions, were studied: benzyl acetate, benzyl formate, benzyl alcohol, 2-bromocyclopropabenzene, 1,6-heptadiyne and 1,5-decadiyne. According to the metastable ion (MI) mass spectra and the He collision induced dissociation (CID) of m/z 89 ions, it is suggested that four structures exist. (Abstract shortened by UMI.)

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Marto, Jarrod A. « External Ion Injection and Applications of Ion Axialization in Fourier Transform Ion Cyclotron Resonance Mass Spectrometry / ». The Ohio State University, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487868114113087.

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Diédhiou, Malick. « Ion Chemistry of Hydrogenated PAHs ». Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/40452.

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Polycyclic aromatic hydrocarbons (PAHs) are a class of organic molecules suggested to constitute roughly 20% of carbon in the interstellar medium (ISM). These species exist in both neutral and ionic forms and both are potentially involved in processes such as H2 formation. Catalyzing H2 formation necessarily involves the participation of hydrogenated PAHs as reaction intermediates. Employing tandem mass spectrometry and imaging photoelectron photoion coincidence spectroscopy and theory, we have explored the unimolecular reactions of five ionized hydrogenated PAHs that vary in degree and position of hydrogenation: tetralin (1,2,3,4-tetrahydronaphthalene), 9,10-dihydroanthracene (DHA+•), 1,2,3,4-tetra- and 1,2,3,4,9,10-hexa-hydrophenanthrene (THP+• and HHP+•) and 1,2,3,4,5,6,7,8-octahydroanthracene (OHA+•). The major reactions observed were the losses of the hydrocarbons CH3•, C2H4 and C3H5• together with H• atom loss. RRKM modeling of the iPEPICO data suggested that the unimolecular chemistries were based around a two-well potential energy surface in each case. Ionized tetralin can lose all four neutrals via H-shift and ring-opening reactions, or CH3• and C2H4 after interconversion to the 1-methylindane ion, a process similar to that found for ionized 1,2-dihydronaphthalene (isomerizing to form the 1-methylindene ion structure). DHA+• exhibits the same reactions previously observed for 1,2-dihydronaphthalene and 9,10-dihydrophenanthrene, namely competing loss of H• and CH3•. However, the energy required for H•-loss, as predicted by RRKM modeling of the iPEPICO results, was lower than the latter ions, presumably due to an expansion of the electron delocalization across the central ring upon dehydrogenation. OHA+• behaves similarly to ionized tetralin, displaying losses of H•, CH3•, C2H4 and C3H5• in its collision induced dissociation (CID) mass spectra, but under iPEPICO conditions CH3•-loss is not observed. THP+• iii and HHP+• have aspects of both DHA+• and OHA+• chemistries, displaying losses of H•, CH3•, C2H4 and C3H5•. Minimum energies for all observed reaction channels were thus obtained, together with selected mechanisms computationally explored at the B3-LYP/6-31+G(d,p) level of theory. The trend in reactivity in going from tetralin and DHA+• to THP+•, HHP+• and ultimately OHA+• sees decreasing abundance of H• and CH3•-loss and an increasing dominance of the formation of C2H4, C3H5• and higher hydrocarbons with degree of hydrogenation as isomerization to a methyl-substituted ion becomes less significant. As this isomerization decreases in significance, the ions become sources of small hydrocarbon molecules and not hydrogen atoms or molecules.

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Hall, Adrian Mark. « Composition and morphology of substorm-associated ion injections ». Thesis, University of Leicester, 1997. http://hdl.handle.net/2381/30662.

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This thesis describes an investigation into the composition and morphology of substorm ion injections at magnetic latitudes and L-shells away from geostationary orbit. Furthermore, the work investigates the Dst-dependent conditions that affect these compositional and spatial characteristics. Count rate and composition measurements in the energy range 80 - 400 keV/q form the basis of the analysis. Near-equatorial observations by the CRRES spacecraft during 1991 have been used to study substorm and near-Earth magnetosphere composition, injection event distribution, and the injection region morphology. Measurements made by the Polar satellite during 1996 extend the study to high magnetic latitudes (50 - 60 Â°) and high L-shells (7 â‰¤ L â‰¤ 22), and are used to investigate the radial morphology of the injection region. For the first time, substorm injection rate as a function of composition, Dst, and injection type has been quantified. In storm time the rate more than doubles. This appears to result from the observed increase in the azimuthal extent of the average injection region. Analysis has shown however, that substorm onset and type (single or multiple injection events) are (for the most part) not significantly composition dependent. The threefold increase in ionospheric-rich event frequency during storm time is principally a result of the increase seen in the equatorial, dusk flank event occurrence. Ion injections have been observed over a large radial extent. Furthermore, ions drift coherently over a large range of L-shells, spanning, at times, from geostationary orbit to L ≈ 18. The inward transport of these ions is not composition dependent. The injected plasma depends on the magnetospheric composition tailward of the spacecraft. This is highly spatially variable and dependent on the past, and prevailing Dst conditions with large (fourfold) enhancements in ionospheric origin material observed inside of L ≈ 7 ( i.e. below the altitude of most substorm onsets) during storm time. The storm time nightside ring current is observed to expand both earthward and tail ward. Out of the equatorial plane, the injection rate is hypothesised to artificially decrease as a result of the tapered, crescent shaped form of the injection region.

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Pollum, Laura L. « Digital ion trap mass spectrometry for cold ion-molecule chemistry ». Thesis, University of Oxford, 2015. http://ora.ox.ac.uk/objects/uuid:18c6451d-d247-4384-9257-f8864e038343.

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A promising new approach for studying cold ion-molecule chemical reactions is the combination of laser- or sympathetically-cooled trapped ions and slow-moving molecules from a cold molecule source, such as a quadrupole velocity selector or a Stark decelerator. Previous reaction studies using trapped atomic ions and slow molecules from a quadrupole velocity selector were able to reach average collision energies as low as 1 K. However, the guided molecules had an approximately room temperature rotational energy distribution, so the reactions studied were not truly cold. Thus, a new molecular source for producing translationally and rotationally cold molecules utilizing buffer gas cooling and quadrupole velocity selection was constructed by K. Twyman and characterized for use in cold reaction studies. This new source of cold molecules is referred to as the buffer gas guide. A new ion trap has been designed and built for use with the existing buffer gas guide. The new ion trap apparatus is compact and mechanically compatible with this new guide. It uses a linear Paul ion trap with cylindrical electrodes to trap ions. Two optical axes (one axial and one radial) enable efficient cooling of small ion crystals. A field-free time-of-flight tube and ion detection assembly are also incorporated into the apparatus. A new technique for determining the mass and quantity of trapped ions has also been developed, termed digital ion trap mass spectrometry. The new technique uses a digital RF waveform to trap ions before ejecting the ions radially from the trap using an ejection pulse applied to the trap electrodes. The ions are then detected after free flight along a time-of-flight tube. This technique was characterized by ejecting crystals of various sizes and compositions: Ca⁺ only, Ca⁺/CaF⁺, Ca⁺/CaOH⁺/CaOD⁺, and Ca⁺/NH⁺₃ /NH⁺₄ /H₃O⁺. A linear relationship between the number of ions ejected (determined by comparing experimental and simulated crystal images) and the integral of the time-of-flight peak was observed for Ca⁺ and Ca⁺/CaF⁺. All mass peaks were resolved. Simulations of the trapped ions and their trajectories through the time-of-flight tube were also performed, and excellent agreement between the simulated and experimental mass resolution was observed. Progress towards combining the buffer gas guide with the previously independent ion trap is also presented. It is anticipated that the combined buffer gas guide ion trap apparatus will enable the study of ion-molecule reactions at low temperatures with translationally and rotationally cold molecules. It is anticipated that the new digital ion trap mass spectrometry technique will simplify the study of reactions when multiple product ions whose masses are separated by only 1 AMU are formed. A new ion trap has been designed and built for use with the existing buffer gas guide. The new ion trap apparatus is compact and mechanically compatible with this new guide. It uses a linear Paul ion trap with cylindrical electrodes to trap ions. Two optical axes (one axial and one radial) enable efficient cooling of small ion crystals. A field-free time-of-flight tube and ion detection assembly are also incorporated into the apparatus. A new technique for determining the mass and quantity of trapped ions has also been developed, termed digital ion trap mass spectrometry. The new technique uses a digital RF waveform to trap ions before ejecting the ions radially from the trap using an ejection pulse applied to the trap electrodes. The ions are then detected after free flight along a time-of-flight tube. This technique was characterized by ejecting crystals of various sizes and compositions: Ca+ only, Ca+/CaF+, Ca+/CaOH+/CaOD+, and Ca+/NH+3/NH+4/H3O+. A linear relationship between the number of ions ejected (determined by comparing experimental and simulated crystal images) and the integral of the time-of-flight peak was observed for Ca+ and Ca+/CaF+. All mass peaks were resolved. Simulations of the trapped ions and their trajectories through the time-of-flight tube were also performed, and excellent agreement between the simulated and experimental mass resolution was observed. Progress towards combining the buffer gas guide with the previously independent ion trap is also presented. It is anticipated that the combined buffer gas guide ion trap apparatus will enable the study of ion-molecule reactions at low temperatures with translationally and rotationally cold molecules. It is anticipated that the new digital ion trap mass spectrometry technique will simplify the study of reactions when multiple product ions whose masses are separated by only 1 AMU are formed.

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Murrell, Jason. « Some studies in ion/molecule reactions on ion trapping instruments ». Thesis, University of Kent, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319223.

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Livres sur le sujet "Ion chemistry and composition"

W, Neilson G., et Enderby J. E, dir. Water and aqueous solutions : Proceedings of the Thirty-seventh Symposium of the Colston Research Society, held in the University of Bristol in April 1985. Bristol : A. Hilger, 1986.

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Serebryakov, Andrey, Tat'yana Smirnova, Valentina Mercheva et Elena Soboleva. Chemistry of combustible minerals. ru : INFRA-M Academic Publishing LLC., 2021. http://dx.doi.org/10.12737/1041945.

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This textbook is a publication of the latest generation, designed to optimize the national project "Education"; develops theoretical knowledge about the genesis of natural liquid, gaseous and solid combustible minerals, the formation of the composition and properties, the practical significance of fuel and energy natural complexes. It is devoted to the study of the composition, properties and classification of oils, gas condensate, natural gases and solid combustible minerals, studied at the level of modern achievements of instrumental analytical and factory equipment in accordance with existing technologies, theories and hypotheses about the genesis of hydrocarbons and Earth sciences. The publication is supplemented with the main directions of processing of combustible minerals. Digital and graphical types of chemical models of the synergy of components of gas and oil deposits are described, which are necessary for predicting the phase state and composition of hydrocarbons and optimizing the directions of processing of marketable products. To facilitate the process of cognition of the origin and formation of the composition and properties of natural combustible minerals, a glossary, tests, as well as questions for the test and exam are offered. To control the knowledge gained by students while studying textbook materials, each chapter is accompanied by questions and tasks. Meets the requirements of the federal state educational standards of higher education of the latest generation. It is intended for students studying in the fields of 05.04.01, 05.03.01 "Geology", 21.05.02 "Applied Geology", as well as for specialists in the field of geology, geochemistry, extraction and processing of oil, gas, gas condensate, solid fuels.

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Surkova, Galina. Atmospheric chemistry. ru : INFRA-M Academic Publishing LLC., 2021. http://dx.doi.org/10.12737/1079840.

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The textbook contains material corresponding to the course of lectures on atmospheric chemistry prepared for students studying meteorology and climatology. The basic concepts of atmospheric chemistry are given, its gaseous components, as well as aerosols and chemical processes related to their life cycles, which are important from the point of view of the formation of the radiation, temperature and dynamic regime of the atmosphere, as well as its pollution, are considered. The main regularities of the transport of impurities in the atmosphere and the role of processes of different spatial and temporal scales in this process are presented. The concept of approaches of varying degrees of complexity used to model the transport of matter in the atmosphere, taking into account its chemical transformations, is presented. The processes in the gaseous and liquid phases that affect the chemical composition and acidity of clouds and precipitation are described. Modern methods of using information about the concentration and state of chemical compounds, including their radioactive and stable isotopes, to obtain information about the meteorological regime of the atmosphere in the present and past are considered. Meets the requirements of the federal state educational standards of higher education of the latest generation. For students of higher educational institutions studying in the field of training "Hydrometeorology".

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Ryabov, Vladimir. Oil and Gas Chemistry. ru : INFRA-M Academic Publishing LLC., 2021. http://dx.doi.org/10.12737/1017513.

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The textbook provides up-to-date data on the composition and properties of hydrocarbons and other oil and gas compounds, on the physical and chemical methods and methods for separating and identifying oil components (molecular spectroscopy, mass spectrometry, NMR spectroscopy, electron paramagnetic resonance, atomic adsorption spectroscopy, neutron activation analysis). The chemistry and mechanism of thermal and catalytic transformations of oil components in the main processes of oil raw materials processing, as well as the problems of the origin of oil and the transformation of oil in the environment are considered. Meets the requirements of the federal state educational standards of higher education of the latest generation. It is intended for training in the course "Chemistry of oil and gas", for the preparation of bachelors, masters and certified specialists in the field of training "Oil and Gas business". It can be used for training in other areas in oil and gas universities and be of interest to specialists working in the field of chemistry and technology of oil refining and in other areas of the oil and gas industry.

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Freiser, Ben S., dir. Organometallic Ion Chemistry. Dordrecht : Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-009-0111-7.

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S, Freiser Ben, dir. Organometallic ion chemistry. Dordrecht : Kluwer Academic Publishers, 1996.

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S, Levine Joel, Langley Research Center, United States. Office of Space Science and Applications et United States. National Aeronautics and Space Administration. Scientific and Technical Information Branch, dir. Space opportunities for tropospheric chemistry research : Proceedings of a workshop. [Washington, D.C.] : National Aeronautics and Space Administration, Scientific and Technical Information Branch, 1987.

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Air composition & chemistry. 2^e éd. Cambridge : Cambridge University Press, 1996.

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Brimblecombe, Peter. Air : Composition & chemistry. Cambridge [Cambridgeshire] : Cambridge University Press, 1986.

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David, Rocklin Roy, dir. Ion exchange in analytical chemistry. Boca Raton, Fla : CRC Press, 1990.

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Chapitres de livres sur le sujet "Ion chemistry and composition"

Sethi, Shruti, Alka Joshi, Bindvi Arora et O. P. Chauhan. « Chemical Composition of Foods ». Dans Advances in Food Chemistry, 1–37. Singapore : Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-4796-4_1.

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Burgot, Jean-Louis. « Solvents—Composition of Solutions ». Dans Ionic Equilibria in Analytical Chemistry, 3–11. New York, NY : Springer New York, 2012. http://dx.doi.org/10.1007/978-1-4419-8382-4_1.

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Li, Li, Joseph P. Kenny, Meng-Shiou Wu, Kevin Huck, Alexander Gaenko, Mark S. Gordon, Curtis L. Janssen et al. « Adaptive Application Composition in Quantum Chemistry ». Dans Lecture Notes in Computer Science, 194–211. Berlin, Heidelberg : Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-02351-4_13.

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Becagli, Silvia. « Aerosol Composition and Reactivity ». Dans Atmospheric Chemistry in the Mediterranean Region, 227–51. Cham : Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-82385-6_13.

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Irvine, William M. « The Molecular Composition of Dense Interstellar Clouds ». Dans Chemistry in Space, 89–121. Dordrecht : Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-009-0695-2_4.

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Feldman, Paul D. « The Volatile Composition of Comets Deduced from Ultraviolet Spectroscopy ». Dans Chemistry in Space, 339–61. Dordrecht : Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-009-0695-2_13.

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Allen, Ralph O., Hany Hamroush et Michael A. Hoffman. « Archaeological Implications of Differences in the Composition of Nile Sediments ». Dans Advances in Chemistry, 33–56. Washington, DC : American Chemical Society, 1989. http://dx.doi.org/10.1021/ba-1988-0220.ch003.

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Varelas, C. G., A. J. Dualeh et C. A. Steiner. « Microdomain Composition in Two-Phase Hydrogels ». Dans Macromolecular Complexes in Chemistry and Biology, 63–70. Berlin, Heidelberg : Springer Berlin Heidelberg, 1994. http://dx.doi.org/10.1007/978-3-642-78469-9_5.

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Alvarado, Matthew J., Kelley C. Barsanti, Serena H. Chung, Daniel A. Jaffe et Charles T. Moore. « Smoke Chemistry ». Dans Wildland Fire Smoke in the United States, 167–98. Cham : Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-87045-4_6.

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AbstractSmoke chemistry (i.e., chemical transformations taking place within smoke plumes) can alter the composition and toxicity of smoke on time scales from minutes to days. Air quality agencies need better information on and better models of smoke chemistry to more accurately characterize the contributions of smoke to ambient ozone and particulate matter, and to better predict good windows for prescribed burning. The ability of these agencies to quantify the contributions of wildland fires to air pollutants and the ability of forest and burn managers to both predict and mitigate these impacts are limited by how current models represent smoke chemistry. This limitation is interconnected with uncertainties in smoke emissions, plume dynamics, and long-range transport. Improving predictive models will require a combination of laboratory, field, and modeling studies focused on enhancing our knowledge of smoke chemistry, including when smoke interacts with anthropogenic emissions and enters indoors.

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Evlanov, E. N., M. N. Fomenkova, V. N. Khromov, L. M. Mukhin, O. F. Prilutsky, R. Z. Sagdeev et B. V. Zubkov. « Features of Experimental Studying of Comet Halley Dust Particles Elemental Composition ». Dans Chemistry in Space, 383–97. Dordrecht : Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-009-0695-2_15.

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Actes de conférences sur le sujet "Ion chemistry and composition"

Shaikin, A. P., I. R. Galiev et V. E. Epishkin. « Effect of the chemical composition of fuel on the duration of the ion current signal during combustion ». Dans INTERNATIONAL CONFERENCE ON PHYSICS AND CHEMISTRY OF COMBUSTION AND PROCESSES IN EXTREME ENVIRONMENTS (COMPHYSCHEM’20-21) and VI INTERNATIONAL SUMMER SCHOOL “MODERN QUANTUM CHEMISTRY METHODS IN APPLICATIONS”. AIP Publishing, 2020. http://dx.doi.org/10.1063/5.0033935.

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Hu, Yisheng, Eric Mackay, Oleg Ishkov et Alistair Strachan. « Predicted and Observed Evolution of Produced Brine Compositions, and Implications for Scale Management ». Dans SPE International Oilfield Scale Conference and Exhibition. SPE, 2014. http://dx.doi.org/10.2118/spe-169765-ms.

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AbstractProduced water was sampled and measured repeatedly during production from an offshore field, and an extensive brine chemistry dataset was developed. Systematic analysis of this dataset enables an in-depth study of brine/brine and brine/rock interactions occurring in the reservoir, with the objective of improving the prediction and management of scale formation, prevention and remediation.A study of the individual ion trends in the produced brine, using the types of plot developed for the Reacting Ions Toolkit (Ishkov et al., 2009), provides insights into what components are involved in in situ geochemical reactions as the brines are displaced through the reservoir, and how the precipitation and dissolution of minerals and the ion exchange reactions occurring within the reservoir can be identified. This information is then used to better evaluate the scale risk at the production wells.A thermodynamic prediction model is used to calculate the risk of scale precipitation in a series of individual produced water samples, thus providing an evaluation of the actual scaling risk in these samples, rather than the usual theoretical estimate based on endpoint formation and injection brine compositions, and the erroneous assumption that no reactions in the reservoir impact the produced water composition. Nonetheless, the usual effects of temperature, pressure and brine composition are accounted for in these calculations using classical thermodynamics. The comparison of theoretical and actual results indicates that geochemical reactions taking place in this given reservoir lead to ion depletion that greatly reduces the severity and potential for scale formation. However, ion exchange reactions are also observed, and these too affect the scale risk, and the effectiveness of scale inhibitors in preventing deposition.Additionally, comprehensive analysis using a geochemical model is used to predict the evolution of the produced brine compositions at the production wells, and to test the assumptions about which in situ reactions are occurring. A good match between the predictions from this geochemical model and the observed produced brine compositions is obtained, suggesting that the key reactions included in the geochemical model are representative of actual field behaviour. This helps to establish confidence that the model can be used as a predictive tool.

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Moravec, Zdeněk, et Vladimír Vanysek. « Gas-grain chemistry in protosolar nebula and composition of comets ». Dans The 50th international meeting of physical chemistry : Molecules and grains in space. AIP, 1994. http://dx.doi.org/10.1063/1.46601.

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JIA, MENGQIU, N. I. KUDRYASHOV et A. MERETSKY. « THE METHOD OF DETERMINATION OF THE SURFACE COMPOSITION OF THE Ir-Rh ALLOYS ». Dans Proceedings of the International Symposium on Solid State Chemistry in China. WORLD SCIENTIFIC, 2002. http://dx.doi.org/10.1142/9789812776846_0071.

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Reilly, P. T. A., M. Yang, R. Gieray, W. B. Whitten et J. M. Ramsey. « Real-Time Laser Ablation MS/MS of Individual Airborne Microparticles ». Dans Laser Applications to Chemical and Environmental Analysis. Washington, D.C. : Optica Publishing Group, 1996. http://dx.doi.org/10.1364/lacea.1996.lthb.4.

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In the past, chemical analysis of airborne particulates was done in the bulk. In other words, particles were collected on a filter and later extracted and subjected to chemical analysis. This provides only a very time consuming statistical constituent analysis of the ensemble of particles that is generally incomplete. All information about composition and chemistry of the individual particles was lost. Recently, mass spectrometric techniques have been applied to individual particles in real-time. Analysis of individual particles via time-of-flight has had great success with the lighter inorganic constituents, but is unenlightening when used on organic based particles. Application of ion trap MS/MS techniques to organically derived particulates permits positive identification of any of the constituents.

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Page, Catherine, Michael Ansell, Betsy Cogan, Grace Neff et Lisa Hommel. « Self-Assembled Inorganic-Organic Multilayer Thin Films ». Dans Chemistry and Physics of Small-Scale Structures. Washington, D.C. : Optica Publishing Group, 1997. http://dx.doi.org/10.1364/cps.1997.csud.5.

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Self-assembly of inorganic-organic multilayer thin films allows the construction of materials with control of thickness, chemical composition, properties and proximity of different layers for use in a variety of applications. By developing different types of organic-inorganic bonding which can be exploited to self-assemble multilayer films we are able to prepare superstructure multilayers consisting of, for example, alternating hafnium-bisphosphonate layers and cobalt diisocyanide layers. The ability to make superstructures with different types of metal-ligand interactions allows more flexibility in the choice of organic linkers, the selection of interesting metal ions, and the properties associated with various combinations of components. Different approaches to incorporating nonlinear optical properties into these multilayers will be presented. Examples of these types of multilayers grown on silicon wafers and their characterization by grazing-angle x-ray diffraction, ellipsometry and second harmonic generation will be discussed. Preliminary results of lithographic approaches to patterning these multilayers in the lateral dimension will also be presented.

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Popescu, Violeta, Alexandru Ciocarlan, Ion Dragalin, Lidia Lungu et Aculina Aricu. « Chemical composition of essential oil of Dill (Anethum graveolens L.) Growing in Republic of Moldova ». Dans New frontiers in natural product chemistry, scientific seminar with international participation. Institute of Chemistry, 2021. http://dx.doi.org/10.19261/nfnpc.2021.ab28.

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Titova, Yu V., A. P. Amosov, D. A. Maidan, G. S. Belova et A. F. Minekhanova. « Physical and chemical features of combustion synthesis of nanopowder composition AlN-SiC using sodium azide ». Dans INTERNATIONAL CONFERENCE ON PHYSICS AND CHEMISTRY OF COMBUSTION AND PROCESSES IN EXTREME ENVIRONMENTS (COMPHYSCHEM’20-21) and VI INTERNATIONAL SUMMER SCHOOL “MODERN QUANTUM CHEMISTRY METHODS IN APPLICATIONS”. AIP Publishing, 2020. http://dx.doi.org/10.1063/5.0034318.

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Yan, Chao, Wei Wang et Wei Wei. « Scale Control for Long Term Well and Facility Preservation ». Dans SPE International Conference on Oilfield Chemistry. SPE, 2021. http://dx.doi.org/10.2118/204282-ms.

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Abstract Oilfield scale and corrosion at oil and gas wells and topside facilities are well known problems. There are many studies towards the control and mitigation of scaling risk during production. However, there has been limited research conducted to investigate the effectiveness of scale control approaches for the preservation of wells and facility during a potential long term shut-in period, which could last more than 6 months. Due to low oil price and harsh economic environment, the need to shut-in wells and facilities can become necessary for operations. Understanding of scale control for a long term period is important to ensure both subsurface and surface production integrity during the shut-in period. The right strategy and treatment approaches in scale management will reduce reservoir and facility damage as well as the resulting cost for mitigation. In this paper, we will review and assess the scale risk for different scenarios for operation shut-in periods and utilize laboratory study to improve the understanding of long-term impact and identify appropriate mitigation strategy. Simulated brine compositions from both conventional and unconventional fields are tested. Commercially available scale inhibitors are used for testing. Various conditions including temperature (131-171 °F), saturation index (1.28-1.73), pH (7.04-8.03) and ratio of scaling ions are evaluated. The tested inhibitor dosage range was 0-300 mg/L. Inhibitor-brine incompatibility was also investigated. Sulfate and carbonate scales such as barium sulfate, strontium sulfate and calcium carbonate are studied as example. This paper will provide an important guidance for the management of well shut- in scenarios for the industry, for both conventional and unconventional fields. Performance of two scale inhibitors for same water composition are demonstrated. The efficiency of scale inhibitor #2 is lower than that of inhibitor #1. A linear correlation is observed for long term scale inhibitor performance in this case. Protection time is thus predicted from data collected from the first 8-week experiments. The predicted protection time at 250 mg/L of inhibitor A and B is 100 weeks and 16 weeks respectively. The actual protection time will be compared to the predicted value. The inhibitor-rock interaction has also been preliminarily studied. The effects of inhibitor adsorption onto formation rock should be considered for chemical treatment design and performance/dosage optimization. This study provides novel information of scale control in a much longer time frame (up to 6 months). Various parameters may have effects on their long term control. Results will benefit the chemical selection and evaluation for long term well shut-in scenario. In addition, brine-inhibitor compatibility is evaluated simultaneously.

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McCanta, Molly, Robert Reid, M. Darby Dyar et Kenneth Livi. « EXPERIMENTAL CONSTRAINTS ON INTERPRETING BASALTIC ALTERATION ON THE SURFACE OF VENUS : EFFECTS OF CHEMISTRY, CRYSTALLINITY, AND ATMOSPHERIC COMPOSITION ». Dans GSA Connects 2022 meeting in Denver, Colorado. Geological Society of America, 2022. http://dx.doi.org/10.1130/abs/2022am-381593.

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Rapports d'organisations sur le sujet "Ion chemistry and composition"

Reid, M. S., X. Wang, N. Utting et C. Jiang. Comparison of water chemistry of hydraulic-fracturing flowback water from two geological locations at the Duvernay Formation, Alberta, Canada. Natural Resources Canada/CMSS/Information Management, 2021. http://dx.doi.org/10.4095/329276.

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We analyzed and compared the water chemistry between 17 Fox Creek region samples, each from a different well, and 23 Three Hills region samples from a single well. Overall, the two regions were similar in chemical composition but showed small differences in some lower abundance dissolved elements. Additionally, we investigated changes in water chemistry of FPW over time from a single well. The majority of water quality parameters and water chemistry remained constant over the 7-month sampling time. Major ion chemistry showed increasing concentrations of Ca and Mg, and a decreasing concentration of SO4. Several trace elements also showed small trends of both increasing and decreasing concentrations over time. There was a strong correlation between Ca and Mg concentrations in both the Fox Creek region samples and Three Hills region samples, which is an indication of the mixing of formation water. However, the correlation between B and Sr was different among two region samples, which is likely due to the delayed mixing of formation water with the fracturing fluids during the flowback at different time periods of post fracturing. Likewise, Fox Creek region samples showed correlations between concentrations of Cl and Ca, Na and Ca, and Na and Mg, but these correlations were not seen in the Three Hills region samples. Geochemical modeling demonstrates that there are potential scales formed in the flowback water, but most of the minerals are still in the dissolution state in the formation. Stable isotopic analysis confirmed the mixing of injection water and the formation water.

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McLuckey, Scott A. High Speed DNA Sequencing by Electrospray and Ion/Ion Chemistry. Office of Scientific and Technical Information (OSTI), septembre 2003. http://dx.doi.org/10.2172/1183476.

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Weiss, W. Jason, Chunyu Qiao, Burkan Isgor et Jan Olek. Implementing Rapid Durability Measure for Concrete Using Resistivity and Formation Factor. Purdue University, 2020. http://dx.doi.org/10.5703/1288284317120.

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The durability of in-place concrete is a high priority issue for concrete pavements and bridges. Several studies have been conducted by INDOT to use electrical resistivity as a measure of fluid transport properties. Resistivity is dependent on the chemistry of the cement and supplementary cementitious system used, as such it has been recommended that rather than specifying resistivity it may be more general to specify the formation factor. Samples were tested to establish the current levels of performance for concrete pavements in the state of Indiana. Temperature and moisture corrections are presented and acceptable accelerated aging procedure is presented. A standardized testing procedure was developed (AASHTO TP 119–Option A) resulting in part from this study that provides specific sample conditioning approaches to address pore solution composition, moisture conditioning, and testing procedures. An accelerated aging procedure is discussed to obtain later age properties (91 days) after only 28 days.

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Brenan, J. M., K. Woods, J. E. Mungall et R. Weston. Origin of chromitites in the Esker Intrusive Complex, Ring of Fire Intrusive Suite, as revealed by chromite trace element chemistry and simple crystallization models. Natural Resources Canada/CMSS/Information Management, 2021. http://dx.doi.org/10.4095/328981.

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To better constrain the origin of the chromitites associated with the Esker Intrusive Complex (EIC) of the Ring of Fire Intrusive Suite (RoFIS), a total of 50 chromite-bearing samples from the Black Thor, Big Daddy, Blackbird, and Black Label chromite deposits have been analysed for major and trace elements. The samples represent three textural groups, as defined by the relative abundance of cumulate silicate phases and chromite. To provide deposit-specific partition coefficients for modeling, we also report on the results of laboratory experiments to measure olivine- and chromite-melt partitioning of V and Ga, which are two elements readily detectable in the chromites analysed. Comparison of the Cr/Cr+Al and Fe/Fe+Mg of the EIC chromites and compositions from previous experimental studies indicates overlap in Cr/Cr+Al between the natural samples and experiments done at &gt;1400oC, but significant offset of the natural samples to higher Fe/Fe+Mg. This is interpreted to be the result of subsolidus Fe-Mg exchange between chromite and the silicate matrix. However, little change in Cr/Cr+Al from magmatic values, owing to the lack of an exchangeable reservoir for these elements. A comparison of the composition of the EIC chromites and a subset of samples from other tectonic settings reveals a strong similarity to chromites from the similarly-aged Munro Township komatiites. Partition coefficients for V and Ga are consistent with past results in that both elements are compatible in chromite (DV = 2-4; DGa ~ 3), and incompatible in olivine (DV = 0.01-0.14; DGa ~ 0.02), with values for V increasing with decreasing fO2. Simple fractional crystallization models that use these partition coefficients are developed that monitor the change in element behaviour based on the relative proportions of olivine to chromite in the crystallizing assemblage; from 'normal' cotectic proportions involving predominantly olivine, to chromite-only crystallization. Comparison of models to the natural chromite V-Ga array suggests that the overall positive correlation between these two elements is consistent with chromite formed from a Munro Township-like komatiitic magma crystallizing olivine and chromite in 'normal' cotectic proportions, with no evidence of the strong depletion in these elements expected for chromite-only crystallization. The V-Ga array can be explained if the initial magma responsible for chromite formation is slightly reduced with respect to the FMQ oxygen buffer (~FMQ- 0.5), and has assimilated up to ~20% of wall-rock banded iron formation or granodiorite. Despite the evidence for contamination, results indicate that the EIC chromitites crystallized from 'normal' cotectic proportions of olivine to chromite, and therefore no specific causative link is made between contamination and chromitite formation. Instead, the development of near- monomineralic chromite layers likely involves the preferential removal of olivine relative to chromite by physical segregation during magma flow. As suggested for some other chromitite-forming systems, the specific fluid dynamic regime during magma emplacement may therefore be responsible for crystal sorting and chromite accumulation.

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Li, Shijian, et Elliot R. Bernstein. Toluene-Water Clusters : Ion Fragmentation and Chemistry. Fort Belvoir, VA : Defense Technical Information Center, février 1992. http://dx.doi.org/10.21236/ada245813.

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Delorey, Dennis E., Paul N. Pruneau et John R. Palys. Magnetic Field Binning and Display of Ion Composition Data. Fort Belvoir, VA : Defense Technical Information Center, mars 1995. http://dx.doi.org/10.21236/ada297275.

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Ervin, Kent M. Hydrocarbon radical thermochemistry : Gas-phase ion chemistry techniques. Office of Scientific and Technical Information (OSTI), mars 2014. http://dx.doi.org/10.2172/1124116.

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Kingston, A. W., A. Mort, C. Deblonde et O H Ardakani. Hydrogen sulfide (H2S) distribution in the Triassic Montney Formation of the Western Canadian Sedimentary Basin. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/329797.

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The Montney Formation is a highly productive hydrocarbon reservoir with significant reserves of hydrocarbon gases and liquids making it of great economic importance to Canada. However, high concentrations of hydrogen sulfide (H2S) have been encountered during exploration and development that have detrimental effects on environmental, health, and economics of production. H2S is a highly toxic and corrosive gas and therefore it is essential to understand the distribution of H2S within the basin in order to enhance identification of areas with a high risk of encountering elevated H2S concentrations in order to mitigate against potential negative impacts. Gas composition data from Montney wells is routinely collected by operators for submission to provincial regulators and is publicly available. We have combined data from Alberta (AB) and British Columbia (BC) to create a basin-wide database of Montney H2S concentrations. We then used an iterative quality control and quality assurance process to produce a dataset that best represents gas composition in reservoir fluids. This included: 1) designating gas source formation based on directional surveys using a newly developed basin-wide 3D model incorporating AGS's Montney model of Alberta with a model in BC, which removes errors associated with reported formations; 2) removed injection and disposal wells; 3) assessed wells with the 50 highest H2S concentrations to determine if gas composition data is accurate and reflective of reservoir fluid chemistry; and 4) evaluated spatially isolated extreme values to ensure data accuracy and prevent isolated highs from negatively impacting data interpolation. The resulting dataset was then used to calculate statistics for each x, y location to input into the interpolation process. Three interpolations were constructed based on the associated phase classification: H2S in gas, H2S in liquid (C7+), and aqueous H2S. We used Empirical Bayesian Kriging interpolation to generate H2S distribution maps along with a series of model uncertainty maps. These interpolations illustrate that H2S is heterogeneously distributed across the Montney basin. In general, higher concentrations are found in AB compared with BC with the highest concentrations in the Grande Prairie region along with several other isolated region in the southeastern portion of the basin. The interpolations of H2S associated with different phases show broad similarities. Future mapping research will focus on subdividing intra-Montney sub-members plus under- and overlying strata to further our understanding of the role migration plays in H2S distribution within the Montney basin.

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Klassen, S. E., P. Rodacy et R. Silva. Reactant ion chemistry for detection of TNT, RDX, and PETN using an ion mobility spectrometer. Office of Scientific and Technical Information (OSTI), septembre 1997. http://dx.doi.org/10.2172/532707.

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Rodacy, P. J., et D. Ingersoll. Control of the reactant ion chemistry for the analysis of explosives by ion mobility spectroscopy. Office of Scientific and Technical Information (OSTI), juillet 1995. http://dx.doi.org/10.2172/93458.

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