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  • 1
    Online Resource
    Online Resource
    Photoelectron Spectroscopy : Chemical and Analytical Aspects. (1972)
    San Diego :Elsevier Science & Technology,
    Details
    Keywords: Electron spectroscopy. ; Electronic books.
    Type of Medium: Online Resource
    Pages: 1 online resource (193 pages)
    Edition: 1st ed.
    ISBN: 9781483152363
    URL: https://ebookcentral.proquest.com/lib/geomar/detail.action?docID=1822080
    DDC: 543/.085
    Language: English
    Note: Front Cover -- Photoelectron Spectroscopy: Chemical and Analytical Aspects -- Copyright Page -- Table of Contents -- PREFACE -- CHAPTER 1. BASIC PRINCIPLES -- INTRODUCTION -- GENERAL APPARATUS -- CHAPTER 2. FACTORS UNDERLYING INSTRUMENTATION AND THEIR BEARING ON THE INTERPRETATION OF RESULTS -- SOURCES -- SAMPLE INTRODUCTION -- ENERGY ANALYSIS OF THE EJECTED ELECTRONS, AND RELATED FACTORS AFFECTING THE RESOLUTION -- ELECTRON MULTIPLIERS AND COUNTING EQUIPMENT -- REFERENCES -- CHAPTER 3. FUNDAMENTAL FACTORS AFFECTING THE APPEARANCE OF A SPECTRUM -- FACTORS INFLUENCING THE SHAPES OF BANDS IN THE SPECTRA -- FACTORS INFLUENCING THE POSITION OF BANDS IN THE SPECTRA -- EXAMPLES OF THE PHOTOELECTRON SPECTRA OF SIMPLE ATOMS AND MOLECULES -- COMPLICATING FACTORS -- AUGER EFFECT AND AUTOIONIZATION -- REFERENCES -- CHAPTER 4. INTERPRETATION OF UV-PHOTOELECTRON SPECTRA -- GENERAL COMMENTS -- ELECTRONEGATIVITY AND INDUCTIVE EFFECTS -- MESOMERIC EFFECTS -- LONE-PAIR" NON-BONDING ORBITALS AND INTERACTIONS BETWEEN THEM -- 7T-ORBITALS -- INTERACTIONS BETWEEN π-SYSTEMS AND LONE-PAIR ORBITALS -- HALOACETYLENES -- cis- AND trans-l,3-DICHLOROPROPENE -- VINYL HALIDES -- SUBSTITUTED BENZENES -- HETEROCYCLIC COMPOUNDS -- STERIC EFFECTS -- THE PERFLUORO EFFECT -- CORRELATIONS -- FUTURE DEVELOPMENTS AND OTHER STUDIES -- REVIEW OF OTHER STUDIES -- REVIEW OF OTHER STUDIES-ADDITIONAL MATERIAL -- REFERENCES -- CHAPTER 5. STRUCTURAL EFFECTS ON CORE ELECTRON BINDING ENERGIES AND X-RAY PHOTO ELECTRON SPECTRA -- CHEMICAL SHIFTS -- REFERENCES -- CHAPTER 6. ANALYTICAL APPLICATIONS -- INTRODUCTION -- ANALYSIS BY X-RAY PES (ESCA) -- QUALITATIVE ANALYSIS -- QUANTITATIVE ANALYSIS -- UV-PES -- QUANTITATIVE ASPECTS -- REFERENCES -- CHAPTER 7. OTHER FORMS OF ELECTRON SPECTROSCOPY -- AUGER ELECTRON SPECTROSCOPY (AS) -- ELECTRON-IMPACT ENERGY-LOSS SPECTROSCOPY (EIS). , ION-NEUTRALIZATION SPECTROSCOPY (INS) -- ANGULAR DISTRIBUTIONS OF PHOTOELECTRONS -- OTHER PHOTOELECTRON TECHNIQUES -- REFERENCES -- APPENDIX 1: INNER-SHELL ORBITAL lONIZATION POTENTIALS FOR ATOMS -- APPENDIX 2: FIRST lONIZATION POTENTIALS OF ATOMS, eV -- APPENDIX 3: SELECTED APPROXIMATE ORBITAL IONIZATION POTENTIALS OF SOME SMALL MOLECULES, eV -- APPENDIX 4: SELECTED VALUES OF INNER-SHELL BINDING ENERGIES MEASURED BY PHOTOELECTRON SPECTROSCOPY -- NITROGEN 1st -- XENON 3d5/2 -- SULPHUR 2p -- IODINE-VARIOUS LEVELS -- OXYGEN 1st -- APPENDIX 5: THE CALCULATION OF PARTIAL CHARGES ON ATOMS IN MOLECULES -- REFERENCE -- APPENDIX 6: PROBABILITY OF AUGER TRANSITION AS A FUNCTION OF ATOMIC NUMBER -- INDEX.
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  • 2
    Online Resource
    Online Resource
    Plant Peroxisomes : Biochemistry, Cell Biology and Biotechnological Applications. (2002)
    Dordrecht :Springer Netherlands,
    Details
    Keywords: Life sciences. ; Electronic books.
    Type of Medium: Online Resource
    Pages: 1 online resource (508 pages)
    Edition: 1st ed.
    ISBN: 9789401598583
    URL: https://ebookcentral.proquest.com/lib/geomar/detail.action?docID=4712919
    Language: English
    Note: Intro -- Title Page -- Copyright -- CONTENTS -- CONTRIBUTORS -- PREFACE -- ACKNOWLEDGEMENTS -- INDEX.
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  • 3
    Book
    Book
    The New Zealand biota - what do we know after 200 years? (1983)
    Details Availability
    Keywords: Konferenzschrift
    Type of Medium: Book
    Pages: 91 S. , graph. Darst. , 8°
    Series Statement: Miscellaneous series / National Museum of New Zealand 7
    Language: English
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  • 4
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    Minor effect of physical size sorting on iron solubility of transported mineral dust (2011)
    In:  Atmospheric Chemistry and Physics
    Details
    Publication Date: 2020-02-12
    Description: Observations show that the fractional solubility of Fe (FS-Fe, percentage of dissolved to total Fe) in dust aerosol increases considerably from 0.1% in regions of high dust mass concentration to 80% in remote regions where concentrations are low. Here, we combined laboratory geochemical measurements with global aerosol model simulations to test the hypothesis that the increase in FS-Fe is due to physical size sorting during transport. We determined the FS-Fe and fractional solubility of Al (FS-Al) in size-fractionated dust generated from two representative soil samples collected from known Saharan dust source regions using a customized dust re-suspension and collection system. The results show that the FS-Fe is size-dependent and ranges from 0.1-0.3% in the coarse size fractions (〉 1 mu m) to similar to 0.2-0.8% in the fine size fractions (〈 1 mu m). The FS-Al shows a similar size distribution to that of the FS-Fe. The size-resolved FS-Fe data were then combined with simulated dust mass concentration and size distribution data from a global aerosol model, GLOMAP, to calculate the FS-Fe of dust aerosol over the tropical and subtropical North Atlantic Ocean. We find that the calculated FS-Fe in the dust aerosol increases systematically from similar to 0.1% at high dust mass concentrations (e. g., 〉 100 mu gm(-3)) to similar to 0.2% at low concentrations (〈 100 mu gm(-3)) due to physical size sorting (i.e., particle gravitational settling). These values are one to two orders of magnitude smaller than those observed on cruises across the tropical and sub-tropical North Atlantic Ocean under an important pathway of Saharan dust plumes for similar dust mass concentrations. Even when the FS-Fe of sub-micrometer size fractions (0.18-0.32 mu m, 0.32-0.56 mu m, and 0.56-1.0 mu m) in the model is increased by a factor of 10 over the measured values, the calculated FS-Fe of the dust is still more than an order of magnitude lower than that measured in the field. Therefore, the physical sorting of dust particles alone is unlikely to be an important factor in the observed inverse relationship between the FS-Fe and FS-Al and the atmospheric mineral dust mass concentrations. The results suggest that processes such as chemical reactions and/or mixing with combustion particles are the main mechanisms to cause the increased FS-Fe in long-range transported dust aerosols.
    Language: English
    Type: info:eu-repo/semantics/article
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  • 5
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    Influence of chemical weathering and aging of iron oxides on the potential iron solubility of Saharan dust during simulated atmospheric processing (2011)
    In:  Global Biogeochemical Cycles
    Details
    Publication Date: 2020-02-12
    Description: The flux of bioavailable Fe from mineral dust to the surface ocean is controlled not only by the processes in the atmosphere but also by the nature and source of the dust. In this study, we investigated how the nature of Fe minerals in the dust affects its potential Fe solubility (Fe-psol) employing traditional and modern geochemical, mineralogical, and microscopic techniques. The chemical and mineralogical compositions, particularly Fe mineralogy, in soil samples as dust precursors collected from North African dust source regions were determined. The Fe-psol was measured after 3 days of contact with sulfuric acid at pH 2 to simulate acid processes in the atmosphere. Fe-psol of the soil dust samples were compared with calculated predictions of Fe-psol based on the amount of individual Fe-bearing minerals present in the samples and Fe solubilities of corresponding standard minerals. The calculated Fe-psol deviated significantly from the measured Fe-psol of the soil dust samples. We attributed this to the variability in properties of Fe minerals (e. g., size of Fe oxides and heterogeneity of chemical compositions of clay minerals) in soil dusts in comparison to the standard minerals. There were, however, clear relationships between the degree of chemical weathering of North African soils and Fe-psol. The Parker index and ratio of ascorbate plus dithionite Fe to total Fe ((FeA+FeD)/FeT) are positively and negatively correlated with Fe-psol, respectively. In addition, the ratio of FeA/(FeA+FeD), which decreases with aging of the Fe oxides, was found to be positively correlated with Fe-psol in the soil dusts. Overall, our results indicate that there is a significant regional variability in the chemical and Fe mineralogical compositions of dusts across North African sources, as a result of the differences in chemical weathering and aging of Fe oxides. Furthermore, the indices for these weathering processes can provide an estimate of the fraction of Fe which can be solubilized if acid processed in the atmosphere.
    Language: English
    Type: info:eu-repo/semantics/article
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  • 6
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    Impacts on iron solubility in the mineral dust by processes in the source region and the atmosphere: A review (2012)
    In:  Aeolian Research
    Details
    Publication Date: 2020-02-12
    Description: Mineral dust is a complex entity containing a range of iron minerals including poorly crystalline to crystalline iron oxides to clay minerals. Important progress has been made to characterize iron mineralogical compositions in the dust recently. These include the quantification of the content of crystalline hematite and goethite, which appear to show a regional variation in North Africa as a result of the differences in the degree of chemical weathering. Fractional Fe solubility (dissolved to total iron, FFS) in the atmospheric aerosols has been reported to range from 0.1% to 80%. However, FFS is usually less than 0.5% in the non-atmospherically-processed dust, suggesting that FFS can be enhanced by atmospheric processes. One of the atmospheric processes, gravitational settling of dust, which has been previously hypothesized to cause the abovementioned enhancement of FFS during dust transport has been shown to be insignificant. Cycling of dust particles in the clouds, in which pH is usually higher than 4, and in the aerosol phase, in which pH is usually substantially lower, can significantly affect iron speciation and FFS. Laboratory experiments showed that a significant amount of iron (〉0.5%) can only be solubilized in the dust when pH is lower than 4. These laboratory data suggest that acid processing rather than cloud processing might be a prime mechanism to cause an increase in FFS in the dust during transport. Further laboratory studies, field measurements, and modelling are needed to increase the ability of models to quantify the atmospheric processing of iron in the dust. (c) 2012 Elsevier B.V. All rights reserved.
    Language: English
    Type: info:eu-repo/semantics/article
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  • 7
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    Formation of Iron Nanoparticles and Increase in Iron Reactivity in Mineral Dust during Simulated Cloud Processing (2009)
    In:  Environmental Science and Technology
    Details
    Publication Date: 2020-02-12
    Description: The formation of iron (Fe) nanoparticles and increase in Fe reactivity in mineral dust during simulated cloud processing was investigated using high-resolution microscopy and chemical extraction methods. Cloud processing of dust was experimentally simulated via an alternation of acidic (pH 2) and circumneutral conditions (pH 5-6) over periods of 24 h each on presieved (〈20 mu m) Saharan soil and goethite suspensions. Microscopic analyses of the processed soil and goethite samples reveal the neo-formation of Fe-rich nanoparticle aggregates, which were not found initially. Similar Fe-rich nanoparticles were also observed in wet-deposited Saharan dusts from the western Mediterranean but not in dry-deposited dust from the eastern Mediterranean. Sequential Fe extraction of the soil samples indicated an increase in the proportion of chemically reactive Fe extractable by an ascorbate solution after simulated cloud processing. In addition, the sequential extractions on the Mediterranean dust samples revealed a higher content of reactive Fe in the wet-deposited dust compared to that of the dry-deposited dust. These results suggest that large variations of pH commonly reported in aerosol and cloud waters can trigger neo-formation of nanosize Fe particles and an increase in Fe reactivity in the dust
    Language: English
    Type: info:eu-repo/semantics/article
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  • 8
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    Iron dissolution kinetics of mineral dust at low pH during simulated atmospheric processing (2011)
    In:  Atmospheric Chemistry and Physics
    Details
    Publication Date: 2020-02-12
    Description: We investigated the iron (Fe) dissolution kinetics of African (Tibesti) and Asian (Beijing) dust samples at acidic pH with the aim of reproducing the low pH conditions in atmospheric aerosols. The Beijing dust and three size fractions of the Tibesti dust (〈 20 mu m: PM20; 〈 10 mu m: PM10; and 〈 2.5 mu m: PM2.5) were dissolved at pH 1, 2 and/or 3 for up to 1000 h. In the first 10 min, all dust samples underwent an extremely fast Fe solubilisation. Subsequently, the Fe dissolution proceeded at a much slower rate before reaching a stable dissolution plateau. The time-dependant Fe dissolution datasets were best described by a model comprising three acid-extractable Fe pools each dissolving according to first-order kinetics. The dissolution rate constant k (h(-1)) of each pool was independent of the source (Saharan or Asian) and the size (PM20, PM10 or PM2.5) of the dust but highly dependent on pH. The "fast" Fe pool had a k (25 h(-1) at pH = 1) of a similar magnitude to "dry" ferrihydrite nanoparticles and/or poorly crystalline Fe(III) oxyhydroxide, while the "intermediate" and "slow" Fe pools had k values respectively 50-60 times and 3000-4000 times smaller than the "fast" pool. The "slow" Fe pool was likely to consist of both crystalline Fe oxide phases (i.e., goethite and/or hematite) and Fe contained in the clay minerals. The initial mass of the "fast", "intermediate" and "slow" Fe pools represented respectively about 0.5-2%, 1-3% and 15-40% of the total Fe in the dust samples. Furthermore, we showed that in systems with low dust/liquid ratios, Fe can be dissolved from all three pools, whereas at high dust/liquid ratios (e.g., in aerosols), sufficient Fe may be solubilised from the "fast" phase to dominate the Fe dissolved and to suppress the dissolution of Fe from the other Fe pools. These data demonstrated that dust/liquid ratio and pH are fundamental parameters controlling Fe dissolution kinetics in the dust. In order to reduce errors in atmospheric and climate models, these fundamental controlling factors need to be included.
    Language: English
    Type: info:eu-repo/semantics/article
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