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81.
Frank Podebrad Martin Heil Saandra Leib Bernhard Geier Thomas Beck Armin Mosandl Adrian C. Sewell Hans Bhles 《Journal of separation science》1997,20(7):355-362
Maple Syrup Urine disease (USUD) is an autosomal recessive inherited metabolic disorder of branched-chain amino acid (L-valin, L-leucine, and L-isoleucine metabolism named after the characteristic smell of affected patients urine. MSUD is caused by a deficiency of the branched-chain α-keto acid dehydrogenase compex resulting in an accumulation of branched-chain aamino acids and the corresponding α-keto-and α-hydroxy acids in blood, urine and cerebrospinal fluid causing neurological damage and mental retardation. The enantioselective analysis of chiral MSUD metabolites and analysis of achiral compounds as corresponding N,O-methoxycarbonyl methyl esters by derivatization with methyl chloroformate (MCF) has been achieved simultaneusly by enantioselective multidimensional gas chromatography-mass spectrometry using heptakis (2,3-di-O-methyl-6-O-tert-butyl-dimethyl-silyl)-β-cyclodextrin as chiral stationary phase. Derivatization with MCF allows the analysis of the structurally different metabolitetes such as branched-chain-carboxylic-, α-oxo-, α-hydroxy- and α-amino acids in a single chromaatographic run. Mass selective detection immensely improves the unequivocaaal identification of metabolites even when they occur as trace compound. The described method allows a reliable screening of MSUD metabolites in patients' urine without time consuming sample preparation and is also suitable for label enrichment analysis without any methodical changes. During this investigation urine sample from three MSUD paatients were analyzed. 相似文献
82.
O. Heil J. Kemmler K. Kroneberger A. Kövér Gy. Szabó L. Gulyás R. DeSerio S. Lencinas N. Keller D. Hofmann H. Rothard D. Berényi K. O. Groeneveld 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1988,9(3):229-234
We have measured the cusp electron yield in coincidence with the transmitted charge state (He0, He+ and He++) when3He+ collides with He and Ne under single collision conditions. For the first time this enables the electron capture to the continuum (ECC) yield to be directly compared with that from electron loss to continuum (ELC). While the ECC contribution is smaller than that from ELC at high projectile velocities (V p >3 au) the data suggest that ECC will dominate belowV p =2.8 au. The relevance of the results to the projectile velocity dependence of existing capture theories is discussed. 相似文献
83.
J. Kemmler O. Heil P. Koschar C. Biedermann H. Rothard K. Kroneberger W. Meckbach K. O. Groeneveld 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1989,14(1):45-49
RatiosN 2s /N 3p of 2s to 3p populations in hydrogen atoms formed by the passage of protons through carbon foils have been measured using the beam-foil-laser excitation method reported very recently. No dependence ofN 2s /N 3p on the incident proton energyE p , in the 100–300 keV energy range analysed, is observed. From the ratioN 3p /N 2p of 3p to 2p beam-foil populations in hydrogen reported previously (N 3p /N 2p independent ofE p forE p >100 keV) and the ratiosN 2s /N 3p measured in the present work, a mean value ofN 2s /N 2p equal to 0.61±0.04 is deduced. These results are compared with available experimental data. 相似文献
84.
Fabian Allmendinger Peter Blümler Michael Doll Olivier Grasdijk Werner Heil Klaus Jungmann Sergej Karpuk Hans-Joachim Krause Andreas Offenhäusser Maricel Repetto Ulrich Schmidt Yuri Sobolev Kathlynne Tullney Lorenz Willmann Stefan Zimmer 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2017,71(4):98
85.
86.
Henry Heil 《Analytical and bioanalytical chemistry》1910,49(2):112-112
87.
Anna Nikiel Peter Blümler Werner Heil Manfred Hehn Sergej Karpuk Andreas Maul Ernst Otten Laura M. Schreiber Maxim Terekhov 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2014,68(11):1-12
We describe a 3He magnetometer capable to measure high magnetic fields (B> 0.1 T) with a relative accuracy of better than 10-12. Our approach is based on the measurement of the free induction decay of gaseous, nuclear spin polarized 3He following a resonant radio frequency pulse excitation. The measurement sensitivity can be attributed to the long coherent spin precession time T2 ? being of order minutes which is achieved for spherical sample cells in the regime of “motional narrowing” where the disturbing influence of field inhomogeneities is strongly suppressed. The 3He gas is spin polarized in situ using a new, non-standard variant of the metastability exchange optical pumping. We show that miniaturization helps to increase T2 ? further and that the measurement sensitivity is not significantly affected by temporal field fluctuations of order 10-4. 相似文献
88.
Matthias Heil Tarak Kharrat Philip A. Cotterill I. David Abrahams 《Journal of sound and vibration》2012,331(21):4774-4784
This paper is concerned with the radiation of sound waves from a submerged cylindrical body which is coated by an imperfect elastic layer; that is, the coating only covers part of the cylinder. The focus of the study is to quantify the effect of the gap in the elastic layer on the radiated acoustic power. A finite element method is employed to determine the acoustic pressure field in the fluid and the displacement field in the coupled layer. This reveals that the effect of a modest sized gap in the coating does not markedly alter the radiated field except at distinct frequencies, at which values the coating exhibits strong fluid-coupled oscillations. We develop a simple analytical model to explain the resonance phenomenon and show that quasi-resonances arise when the wavelength of the deformation pattern ‘matches’ the azimuthal length of the surface of the coating. This resonant behaviour is conveniently captured by a single parameter Q, which is the ratio of the typical inertial fluid pressure induced by the wall oscillation to the stiffness of the elastic coating. For each choice of material parameters, there is shown to be an infinite set of values of Q corresponding to distinct quasi-resonance mode numbers. The effects on the radiated field due to variations in various physical parameters, such as acoustic wavenumber and elastic layer inertia, are also discussed. 相似文献
89.
P. Achenbach D. Baumann R. Böhm B. Boillat D. Bosnar C. Carasco M. Ding M. O. Distler J. Friedrich W. Glöckle J. Golak Y. Goussev P. Grabmayr W. Heil A. Hügli P. Jennewein G. Jover Ma nas J. Jourdan H. Kamada T. Klechneva B. Krusche K. W. Krygier J. G. Llongo M. Lloyd M. Makek H. Merkel C. Micheli U. Müller A. Nogga R. Neuhausen Ch. Normand L. Nungesser A. Ott E. Otten F. Parpan R. Pérez Benito M. Potokar D. Rohe D. Rudersdorf J. Schmiedeskamp M. Seimetz I. Sick S. Širca R. Skibiński S. Stave G. Testa R. Trojer Th. Walcher M. Weis H. Witała H. Wöhrle 《The European Physical Journal A - Hadrons and Nuclei》2005,25(2):177-183
90.
W. Ketter W. Heil G. Badurek M. Baron E. Jericha R. Loidl H. Rauch 《The European Physical Journal A - Hadrons and Nuclei》2006,27(2):243-256
Improved knowledge of the real part of the neutron scattering length of 3He is important for further development of nuclear few-body theory, as well as for a thorough understanding of neutron scattering
off quantum liquids. The real part of the bound incoherent neutron scattering length bi' has recently been measured directly with an experimental uncertainty of better than 1% by means of spin echo spectrometry.
The uncertainty of the more fundamental bound multiplet scattering lengths b±' is thus limited by today's 1.2% uncertainty of the spin-independent coherent part bc'. Employing the skew-symmetric perfect crystal Si-interferometer at the S18 experimental site at ILL, Grenoble, we have re-measured
the real part of the bound coherent neutron scattering length bc' of 3He. Our result bc' = 6.010(21)fm exhibits a significant deviation compared to the latest accepted value bc' = 5.74(7)fm (H. Kaiser, H. Rauch, G. Badurek, W. Bauspiess, U. Bonse, Z. Phys. A 291, 231 (1979)). Including the known value of the incoherent neutron scattering length, we obtain new values for the real parts
of the free singlet and triplet scattering lengths, a-' = 7.573(30)fm and a+' = 3.480(18)fm. Our result contravenes by more than 7 standard deviations the measurement of the same physical quantity that
has recently been performed by a group at NIST in a very similar experiment (P.R. Huffman, D.L. Jacobson, K. Schoen, M. Arif,
T.C. Black, W.M. Snow, S.A. Werner, Phys. Rev. C 70, 014004 (2004)) which yielded bc' = 5.853(7)fm. 相似文献