| 1. |
- Choularton, T. W., et al.
(author)
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The Great Dun Fell Cloud Experiment 1993 : An overview
- 1997
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In: Atmospheric Environment. - 1352-2310. ; 31:16, s. 2393-2405
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Journal article (peer-reviewed)abstract
- The 1993 Ground-based Cloud Experiment on Great Dun Fell used a wide range of measurements of trace gases, aerosol particles and cloud droplets at five sites to study their sources and sinks especially those in cloud. These measurements have been interpreted using a variety of models. The conclusions add to our knowledge of air pollution, acidification of the atmosphere and the ground, eutrophication and climate change. The experiment is designed to use the hill cap cloud as a flow-through reactor, and was conducted in varying levels of pollution typical of much of the rural temperate continental northern hemisphere in spring-time.
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| 2. |
- Bower, K. N., et al.
(author)
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The Great Dun Fell experiment 1995 : An overview
- 1999
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In: Atmospheric Research. - 0169-8095. ; 50:3-4, s. 151-184
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Journal article (peer-reviewed)abstract
- During March and April of 1995 a major international field project was conducted at the UMIST field station site on Great Dun Fell in Cumbria, Northern England. The hill cap cloud which frequently envelopes this site was used as a natural flow through reactor to examine the sensitivity of the cloud microphysics to the aerosol entering the cloud and also to investigate the effects of the cloud in changing the aerosol size distribution, chemical composition and associated optical properties. To investigate these processes, detailed measurements of the cloud water chemistry (including the chemistry of sulphur compounds, organic and inorganic oxidised nitrogen and ammonia), cloud microphysics and properties of the aerosol and trace gas concentrations upwind and downwind of the cap cloud were undertaken. It was found that the cloud droplet number was generally strongly correlated to aerosol number concentration, with up to 2000 activated droplets cm-3 being observed in the most polluted conditions. In such conditions it was inferred that hygroscopic organic compounds were important in the activation process. Often, the size distribution of the aerosol was substantially modified by the cloud processing, largely due to the aqueous phase oxidation of S(IV) to sulphate by hydrogen peroxide, but also through the uptake and fixing of gas phase nitric acid as nitrate, increasing the calculated optical scattering of the aerosol substantially (by up to 24%). New particle formation was also observed in the ultrafine aerosol mode (at about 5 nm) downwind of the cap cloud, particularly in conditions of low total aerosol surface area and in the presence of ammonia and HCl gases. This was seen to occur at night as well as during the day via a mechanism which is not yet understood. The implications of these results for parameterising aerosol growth in Global Climate Models are explored.
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| 3. |
- Cederfelt, S. I., et al.
(author)
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Field validation of the droplet aerosol analyser
- 1997
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In: Atmospheric Environment. - 1352-2310. ; 31:16, s. 2657-2670
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Journal article (peer-reviewed)abstract
- A new instrument for the study of cloud droplets and its relation to aerosol particles, the droplet aerosol analyser (DAA), was for the first time used in a field campaign. The DAA has the unique feature of measuring the ambient size of cloud droplets or cloud interstitial aerosol particles together with the size of its dry residue. This is obtained with a two-parameter data acquisition technique which results in a three-dimensional data set (ambient size, dry residue size, number concentration). The principle and design of the DAA is briefly described. The DAA was intercompared with differential mobility particle sizers, particulate volume monitors and a forward scattering spectrometer probe with respect to interstitial and cloud droplet dry residue size distribution as well as particle-size-dependent scavenging due to cloud droplet nucleation and for cloud droplet number concentration and size distribution and cloud liquid water concentration. Overall, the DAA showed good agreement with respect to all these six aerosol/cloud properties.
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| 4. |
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| 5. |
- Martinsson, B. G., et al.
(author)
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Experimental determination of the connection between cloud droplet size and its dry residue size
- 1997
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In: Atmospheric Environment. - 1352-2310. ; 31:16, s. 2477-2490
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Journal article (peer-reviewed)abstract
- The droplet activation process and droplet growth was studied during early stages of the formation of orographically-induced clouds. The experimental results were compared with the results obtained with a closed parcel, adiabatic cloud model. Good agreement was in most cases found between model and measurements with respect to cloud droplet number concentration, cloud droplet solute concentration and particle sizes scavenged due to cloud droplet nucleation. The experimental results were mainly obtained with a new instrument, the droplet aerosol analyser (DAA), which allows the determination of ambient sizes of cloud droplets and interstitial aerosol particles directly connected with the size of its dry residue in a two-parameter data acquisition. The resulting three-dimensional data set (ambient size, dry size, number concentration) was utilised to determine several cloud/aerosol properties, whereof some unique.
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| 6. |
- Andersson, S, et al.
(author)
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CO dissociation characteristics on size-distributed rhodium islands on alumina model substrates
- 1998
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In: JOURNAL OF CHEMICAL PHYSICS. - : AMER INST PHYSICS. - 0021-9606. ; 108:7, s. 2967-2974
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Journal article (other academic/artistic)abstract
- The dissociation of CO on size-distributed Rh particles supported on a thin alumina film has been studied with high resolution X-ray Photoelectron Spectroscopy (XPS) and X-ray Absorption Spectroscopy (XAS). Adsorbed CO dissociates upon heating to temperat
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| 7. |
- Andersson, S, et al.
(author)
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Metal-oxide interaction for metal clusters on a metal-supported thin alumina film
- 1999
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In: SURFACE SCIENCE. - : ELSEVIER SCIENCE BV. ; 442:1
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Other publication (other academic/artistic)abstract
- The interaction between deposited metal clusters and a thin model alumina film grown on NiAl(110) have been studied using X-ray absorption spectroscopy (XAS) and core and valence photoelectron spectroscopy. A lower limit for the fundamental gap of the sup
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| 8. |
- Andersson, S, et al.
(author)
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Temperature dependent XPS study of CO dissociation on small Rh particles
- 1998
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In: VACUUM. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0042-207X. ; 49:3, s. 167-170
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Journal article (other academic/artistic)abstract
- We have used temperature dependent X-ray Photoelectron Spectroscopy (XPS) to study the heating-induced CO dissociation on oxide-supported Rh particles through observation of changes undergone by the adsorbate CO and the formation of atomic carbon from the
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| 9. |
- Frank, D, et al.
(author)
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A novel pleckstrin homology-related gene family defined by Ipl/Tssc3, TDAG51, and Tih1 : tissue-specific expression, chromosomal location, and parental imprinting.
- 1999
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In: Mamm Genome. - : Springer Science and Business Media LLC. - 0938-8990. ; 10:12, s. 1150-9
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Journal article (peer-reviewed)abstract
- We previously described a gene, Ipl (Tssc3), that is expressed selectively from the maternal allele in placenta, yolk sac, and fetal liver and that maps within the imprinted domain of mouse distal Chromosome (Chr) 7/human Chr 11p15.5 (Hum Mol Genet 6, 2021, 1997). Ipl is similar to TDAG51, a gene that is involved in FAS/CD95 expression. Here we describe another gene, Tih1 (TDAG/Ipl homologue 1), with equivalent sequence similarity to Ipl. Structural prediction indicates that the products of these three genes share a central motif resembling a pleckstrin-homology (PH) domain, and TIH1 protein has weak sequence similarity to the PH-domain protein SEC7/CYTOHESIN. Like Ipl, Tih1 is a small gene with a single small intron. Tih1 maps to distal mouse Chr 1 and human Chr 1q31, chromosomal regions that have not shown evidence for imprinting and, in contrast to Ipl, Tih1 is expressed equally from both parental alleles. Ipl, Tih1, and TDAG51 have overlapping but distinct patterns of expression. Tih1 and TDAG51 are expressed in multiple fetal and adult tissues. In contrast, during early mouse development Ipl mRNA and protein are highly specific for two tissues involved in maternal/fetal exchange: visceral endoderm of the yolk sac and labyrinthine trophoblast of the placenta. These findings highlight the dominance of chromosomal context over gene structure in some examples of parental imprinting and extend previous evidence for placenta-specific expression of imprinted genes. The data also define a new subfamily of PH domain genes.
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| 10. |
- Frank, M, et al.
(author)
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Particle size dependent CO dissociation on alumina-supported Rh: a model study
- 1997
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In: CHEMICAL PHYSICS LETTERS. - : ELSEVIER SCIENCE BV. - 0009-2614. ; 279:1-2, s. 92-99
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Journal article (other academic/artistic)abstract
- Via deposition of Ph from the gas phase onto a thin, well-ordered alumina film we have prepared various of alumina-supported Rh particle systems. The morphologies and particle sizes have been characterised with spot profile analysis LEED and STM measureme
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