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41.
Tapan K. Majumdar Marcos N. Eberlin R. Graham Cooks Mark M. Green Beth Muñoz Mike P. Reidy 《Journal of the American Society for Mass Spectrometry》1991,2(2):130-148
Homopolymers and copolymers of alkylisocyanates having n-hexyl, 2,6-dimethylheptyl, 3,7-dimethyloctyl, and (2,2-dimethyl-1,3-dioxolan-4-yl)methyl substituents underwent thermal degradation in the course of desorption electron ionization to yield trimers and monomers that were characterized in situ by tandem mass spectrometry. The trimers were trisubstituted cyanuric acids, the protonated molecules displaying a characteristic series of alkene eliminations on collision-induced dissociation to yield protonated cyanuric acid, m/ z 130. Confirmation of the identity of the pyrolysates was obtained by using two types of MS3 experiments: the reaction intermediate scan and the two-dimensional familial scan. The ion chemistry of the trimers and of the protonated monomer, the alkylisocyanate, was elucidated. Among the many interesting fragmentation processes undergone by the ionized trimers were a and 3 C-C bond cleavages and charge-remote fragmentations, which provided information on branching in the alkyl substituent. The dioxolane-containing substituent showed unique ion chemistry. The monomer distribution in the copolymers was deduced from the abundances of the various protonated trimers. The distribution was found to be random in all copolymers except that containing the dioxolane substituent. 相似文献
42.
Lorlyn Reidy Rachel Williams Derek Bussan Steve Brewer 《International journal of environmental analytical chemistry》2013,93(13):1273-1287
Outgassing of volatile sulphur compounds from gypsum drywall from some sources has resulted in odours, corrosion of wiring and metals and health problems for homeowners. Infrared spectroscopy has been the primary analytical tool to identify ‘problematic’ drywall. In this paper, we demonstrate that elemental fingerprinting using inductively coupled plasma mass spectrometry and multivariate statistics is an effective alternative. The approach also showed potential in determining the geographic source of gypsum. Nineteen elements (Al, Ba, Ca, Cd, Co, Cr, Cs, Cu, Fe, Mg, Mn, Ni, Pb, Rb, Sr, Tl, U, V and Zn) were measured in 20 samples of drywall, half of which were classified as positive for contamination by Fourier Transform Infrared Spectroscopy. Gypsum from three different mines and a flue gas desulphurisation plant were also analysed. Principal component analysis and multivariate analysis of variance of the elemental data showed significant differences between the problematic and non-problematic drywall and between sources of gypsum. Strontium averaged 1800 ± 500 µg/g in problematic drywall compared to 400 ± 100 µg/g in non-problematic drywall (p < 0.0001). 相似文献
43.
Reidy LJ Meier-Augenstein W Kalin RM 《Rapid communications in mass spectrometry : RCM》2005,19(13):1899-1905
Paints have a dual role in society, to protect materials from environmental agents such as ultraviolet light, moisture and oxygen, and to make painted materials look more attractive. Variability in paint samples is often due to binder and pigment type within the sample. The most common resin used in decorative paints is drying oil alkyd resin, which incorporates soybean oil and vinyl acrylic based latexes. Traditional analytical methods used by forensic scientists may be able to say whether two paint samples are indistinguishable but cannot conclusively say that they both originate from the same source. To find out if isotopic composition can provide an added dimension of information, 28 different white architectural paints were analysed for (13)C abundance using isotope ratio mass spectrometry. In addition, variations in application, drying time and thickness were also investigated to assess the discriminatory power of (13)C data from white paints with an unknown history. Preliminary results indicate that this method could aid screening of paint samples. 相似文献
44.
A. Kreissl A. D. Hancock H. Koch Th. Köhler H. Poth U. Raich D. Rohmann a. Wolf L. Tauscher A. Nilsson M. Suffert M. Chardalas S. Dedoussis H. Daniel T. von Egidy F. J. Hartmann W. Kanert H. Plendl G. Schmidt J. J. Reidy 《Zeitschrift fur Physik C Particles and Fields》1988,37(4):557-561
A high-precision measurement of the finestructure splitting in the circular 11→10 X-ray transition of \(\bar p^{208} Pb\) was performed. The experimental value of 1199(5) eV is in agreement with QED calculations. From that value the magnetic moment of the antiproton was deduced to be ?2.8005(90)μ nucl. With this result the uncertainty of the previous world average value was reduced by a factor of ≈2. A comparison with the corresponding quantity of the proton now yields: \({{\left( {\mu _p - \left| {\left\langle {\mu _{\bar p} } \right\rangle } \right|} \right)} \mathord{\left/ {\vphantom {{\left( {\mu _p - \left| {\left\langle {\mu _{\bar p} } \right\rangle } \right|} \right)} {\mu _p }}} \right. \kern-0em} {\mu _p }} = \left( { - 2.4 \pm 2.9} \right) \times 10^{ - 3} \) . 相似文献
45.
46.
E. F. Moser H. Daniel T. von Egidy F. J. Hartmann W. Kanert G. Schmidt Ye. S. Golubeva A. S. Iljinov M. Nicholas J. J. Reidy 《Zeitschrift für Physik A Hadrons and Nuclei》1989,333(1):89-105
The distributions of residual nuclei after annihilation of stopped antiprotons in92Mo,95Mo,98Mo and165Ho targets have been measured by means of the induced radioactivity. In the case of the165Ho target the residual nucleus116Te was observed thus indicating that about 50 nucleons may be emitted after annihilation. The distributions have also been calculated with two versions of an intranuclear cascade model. The agreement between theory and experiment is satisfactory. The effects of heavy mesons in the annihilation process, of local reduction of the nuclear density during the intranuclear cascade and of multifragmentation are discussed. 相似文献
47.
Aitala EM Amato S Anjos JC Appel JA Ashery D Banerjee S Bediaga I Blaylock G Bracker SB Burchat PR Burnstein RA Carter T Carvalho HS Copty NK Cremaldi LM Darling C Denisenko K Devmal S Fernandez A Fox GF Gagnon P Gobel C Gounder K Halling AM Herrera G Hurvits G James C Kasper PA Kwan S Langs DC Leslie J Lundberg B Magnin J Massafferri A MayTal-Beck S Meadows B de Mello Neto JR Mihalcea D Milburn RH de Miranda JM Napier A Nguyen A d'Oliveira AB O'Shaughnessy K Peng KC Perera LP Purohit MV 《Physical review letters》2001,86(5):765-769
From a sample of 848+/-44 D(+)(s)-->pi(-)pi(+)pi(+) decays, we find gamma(D(+)(s)-->pi(-)pi(+)pi(+))/gamma(D(+)(s)-->straight phipi(+)) = 0.245+/-0.028(+0.019)(-0.012). Using a Dalitz plot analysis of this three body decay, we find significant contributions from the channels rho(0)(770)pi(+), rho(0)(1450)pi(+), f(0)(980)pi(+), f(2)(1270)pi(+), and f(0)(1370)pi(+). We also present the values obtained for masses and widths of the resonances f(0)(980) and f(0)(1370). 相似文献
48.
T. von Egidy H. Daniel F. J. Hartmann W. Kanert E. F. Moser Ye. S. Golubeva A. S. Iljinov J. J. Reidy 《Zeitschrift für Physik A Hadrons and Nuclei》1990,335(4):451-457
Antiprotons have been stopped in a target of Ba(NO3)2. The induced radioactivity from antiproton annihilation in Ba was used to determine the distribution of residual nuclei. The results are compared with intranuclear cascade calculations. The agreement between theory and experiment is very good. 相似文献
49.
D. Rohmann H. Barth A. D. Hancock H. Koch Th. Köhler A. Kreissl H. Poth U. Raich A. Wolf L. Tauscher M. Suffert M. Chardalas S. Dedoussis A. Nilsson W. Kanert T. von Egidy F. J. Hartmann G. Schmidt J. J. Reidy 《Zeitschrift für Physik A Hadrons and Nuclei》1986,325(3):261-265
The yields of the atomic 4→3 transitions in antiprotonic14N,16,17,18O,19F, and23Na were measured at the CERN antiproton facility, LEAR. From these, the widths Γup of the 4f levels were determined to be 136±19meV (14N); 603±22 meV (16O); 731±35 meV (17O); 795±23 meV (18O); 2.79±0.16 eV (19F); and 23.8±7.4 eV (23Na). 相似文献
50.
Aitala EM Amato S Anjos JC Appel JA Ashery D Banerjee S Bediaga I Blaylock G Bracker SB Burchat PR Burnstein RA Carter T Carvalho HS Copty NK Cremaldi LM Darling C Denisenko K Devmal S Fernandez A Fox GF Gagnon P Gobel C Gounder K Halling AM Herrera G Hurvits G James C Kasper PA Kwan S Langs DC Leslie J Lundberg B Magnin J MayTal-Beck S Meadows B de Mello Neto JR Mihalcea D Milburn RH de Miranda JM Napier A Nguyen A d'Oliveira AB O'Shaughnessy K Peng KC Perera LP Purohit MV Quinn B Radeztsky S 《Physical review letters》2001,86(18):3969-3972
We report results of a search for flavor-changing neutral current (FCNC), lepton flavor, and lepton-number violating decays of the D0 (and its antiparticle) into three and four bodies. Using data from Fermilab charm hadroproduction experiment E791, we examine modes with two leptons (muons or electrons) and a rho(0), K( *0), or straight phi vector meson or a nonresonant pi(pi), Kpi, or KK pair of pseudoscalar mesons. No evidence for any of these decays is found. Therefore, we present branching-fraction upper limits at 90% confidence level for the 27 decay modes examined (18 new). 相似文献