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  • 1
    Electronic Resource
    Electronic Resource
    Unimolecular dissociation dynamics of highly vibrationally excited DCO (X˜ 2A). I. Investigation of dissociative resonance states by stimulated emission pumping spectroscopy (1997)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 106 (1997), S. 5333-5358 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The vibrational level structure and unimolecular dissociation dynamics of highly vibrationally excited X˜ 2A DCO were investigated using the method of stimulated emission pumping spectroscopy (SEP). Single vibration-rotation states were probed with excitation energies up to E(X˜)=18 200 cm−1, (approximate)12 700 cm−1 above the asymptotic D-CO dissociation limit. The vibrational level structure of the molecule was found to be determined by distinctive polyads arising from a 1:1:2 resonance between the CD stretching, CO stretching, and DCO bending vibrations. Anharmonic coupling mechanisms give rise to considerable level mixings, especially regarding the CD and CO stretching motion. Thus, only a minority of vibrational states can be unambiguously assigned. The spectral line shape profiles of (approximate)100 highly excited "resonance states" in the continuum above the D-CO dissociation limit were measured at high resolution. The profiles are homogeneously broadened. The unimolecular decay rates, obtained from the observed line widths, were observed to fluctuate by more than two orders of magnitude in a strikingly state specific manner. The decay rates on average increase with increasing vibrational excitation energy. The state resolved experimental data are compared to predictions of the microcanonical specific unimolecular rate coefficients calculated from different statistical models. Serious problems were encountered considering the calculation of the density of states of the molecules in the continuum region of the potential energy surface regarding the contribution of the disappearing oscillator. Despite tentative corrections, the calculated rate coefficients were to too high by one to two orders of magnitude. Overall, the unimolecular dynamics of DCO appears to conform to an intermediate case between the strictly vibrationally "mode specific" and the "statistical" limits. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.473603
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  • 2
    Electronic Resource
    Electronic Resource
    Vibrationally enhanced inelastic atom–molecule cross sections at very low energies (1992)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 96 (1992), S. 8819-8829 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Rate constants for inelastic processes in Na2 (v,j)–Ne, Ar, Na collisions are determined at a mean collision energy of the order of 1 meV in a supersonic seeded beam arrangement. The initial vibrational state v and rotational state j is varied in the range 4≤v≤35 and 5≤j≤25. The Na2 molecules are excited by Franck–Condon pumping near the transition region to free molecular flow and the flux of molecules which survive in the level (v,j) is monitored far downstream behind a small aperture. It is shown that elastic processes do not contribute to the observed signal. The magnitude of the cross section for the sum of all inelastic processes is as large as several hundred A(ring)2. It is found that the vibrational motion of the molecule, which carries an energy of up to 500 meV, strongly influences the collision dynamics. The rate constant increases with v by about 35% within the range of vibrational levels studied here. Some state-to-state rate constants are also reported. The experimental results are in good agreement with data from quasiclassical trajectory calculations on a semiempirical bond-distance-dependent potential surface. The observations can be rationalized by realizing that the long range attraction increases with vibrational excitation since the polarizability of the molecule increases. Furthermore, the vibrational excitation in combination with the relatively long interaction time due to the low collision energy enhances the probability for a change of the initial quantum state of the molecule.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.462239
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  • 3
    Electronic Resource
    Electronic Resource
    A 2.45 GHz multicusp ECR-ion source for neutral–beam diagnostics at the tokamak TEXTOR : Proceedings of the fourth International Conference on Ion Sources (1992)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 2544-2546 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: In order to implement a new setup for neutral–beam activated impact excitation spectroscopy at the nuclear fusion experiment "TEXTOR'' (Tokamak Experiment for Technology Oriented Research) a 2.45 GHz ECR multicusp ion source was built. Special emphasis was given to extract an intense He+-ion beam, which will be used in the forthcoming experiment. After neutralization the slow (2.2 × 107 cm/s, 1 keV) He atoms are injected into the tokamak plasma. Necessarily the atom beam has to have a small divergence. To optimize the extraction optics, calculations concerning the multihole extraction aperture have been made, taking different ECR-plasma parameters into account. The divergence shows a strong dependence on the extracted beam current density ((approximately-greater-than)5 mA/cm2) and the chosen optics. The ion source has to be operated in a pulsed mode (max. 5 kHz, duty cycle 50%) due to experimental requirements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1142883
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  • 4
    Electronic Resource
    Electronic Resource
    Cerebrovascular doppler examination and cerebral angiography-alternative or complementary? (1978)
    Springer
    Neuroradiology 16 (1978), S. 140-144 
    Details
    ISSN: 1432-1920
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Obstructions in the extracranial cerebral arteries can be detected noninvasively by directional Doppler ultrasound technique using ‘indirect’ and ‘direct’ criteria. The indirect criteria are based on measurement of flow in the common carotid and in the terminal branches of the ophthalmic artery before and after the common carotid artery and branches of the external carotid artery are compressed. With the direct criteria, internal and external carotid artery are differentiated by diastolic flow, and local inhomogeneities of flow (turbulence) are detected. Flow in the vertebral artery is picked up transorally in the oropharynx. The Doppler examination was used in 2230 patients of whom 436 underwent angiography. The results of Doppler and angiography correlated in more than 90% of the cases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00395229
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  • 5
    Electronic Resource
    Electronic Resource
    146. Langzeitresultate nach Rekonstruktion der proximalen Arteria subclavia (1979)
    Springer
    Langenbeck's archives of surgery 349 (1979), S. 541-541 
    Details
    ISSN: 1435-2451
    Keywords: Endarterectomy ; Proximal subclavian artery ; Long-term results ; Endarterektomie ; Proximate Arteria subclavia ; Langzeitresultate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 80 Patienten wurden wegen 70 Verschlüssen oder Stenosen, 7 Aneurysmen, 2 Aplasien und 2 Verletzungen der prox. A. subclavia operiert. Bei 67 Patienten war die Endarterektomie die Operation der Wahl. 1 Patient verstarb postoperativ. 72 Patienten wurden 5,5 Jahre nach der Operation nachkontrolliert. 92% waren beschwerdefrei, 94,5 % zeigten einen anterograden Vertebralisfluß. Die Endarterektomie ist in geübten Händen eine einfache und wirksame Operation. Die Mortalität ist gering und die Langzeitresultate sind außerordentlich gut.
    Notes: Summary 80 patients had been operated on for 70 occlusions or stenosis, 7 aneurysm, 2 aplasia and 2 injuries of the prox. subclavian artery. 67 pat. were endarterectomized. 1 pat. died in hospital. 72 pat. had a follow-up after 5.5 years. 92 % were symptom-free. 94.5 % had an anterograde flow in the vertebral artery. The endarterectomy of the prox. subclavian artery is in our hands the method of choice. The mortality is very low and the long-term results are excellent.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01729604
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  • 6
    Electronic Resource
    Electronic Resource
    Knochenmarksfunktionsprüfung mit unspezifischen Reizstoffen (1959)
    Springer
    Journal of molecular medicine 37 (1959), S. 1003-1005 
    Details
    ISSN: 1432-1440
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Zusammenfassung Anhand von 367 Untersuchungen mit Acetylreizstoff in einer Dosis von 20 γ i. v. und von 157 Untersuchungen mit Pyrexal in einer Dosis von 0,04 γ i. v. konnte gezeigt werden, daß die mit den beiden Testsubstanzen erzielten Resultate der Knochenmarksfunktionsprüfung sowohl in bezug auf die Leukocytenveränderung als auch in bezug auf die Nebenwirkungen übereinstimmen. Eine Erhöhung der Pyrexaldosis auf 0,05 γ i. v. bringt keine Änderung der leukocytären Reaktion, wohl aber eine ganz erhebliche Verstärkung der Nebeneffekte.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01483207
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  • 7
    Electronic Resource
    Electronic Resource
    Velocity control and cooling of an atomic beam using a modeless laser (1991)
    Springer
    The European physical journal 18 (1991), S. 307-308 
    Details
    ISSN: 1434-6079
    Keywords: 33.80.Pj ; 42.50.Vk
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A newly developed continuous wave broadband laser which lacks mode structure in the frequency domain is employed together with a single mode laser beam to decelerate and cool metastable neon atoms. The velocity of the atoms in the beam can be set to a desired velocity by tuning the frequency of the single mode laser.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426590
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