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21.
H. R. Khan K. Lüders Ch. J. Raub G. Roth 《Zeitschrift für Physik B Condensed Matter》1980,38(1):27-33
Superconductivity, structure and electrical resistance behaviour of -phase alloys of Nb–Rh and Ta–Rh are investigated. The Ta–Rh alloys do not become superconducting above 1.2 K. The
andH
c2
(0) values of a homogeneous alloy with the composition Nb65.2Rh34.8 are 2.95 K, 13.9 kG/K and 23 kG, respectively, whereas for an inhomogeneous alloy with the composition Nb63.7Rh36.3 these values are 4.24 K, 5.5 kG/K and 14 kG, respectively. Splat quenching results in a substantial increase in the
andH
c2
(0) values of the Rh-rich sample. Annealing (900°C, 100 h) of the Rh-rich sample leads only to small changes in the superconducting properties but a small amount of Nb–Rh solid solution has been formed. The electrical resistance of Nb65.2Rh34.8 decreases with decreasing temperature and varies asT
0.5 between 150 and 240 K and asT between 60 and 140 K. For Ta70.0Rh30.0 the temperature coefficient changes to negative values below 170K. values are calculated for Nb–Rh using McMillan's formula. An estimatedT
c
value of Ta–Rh is 0.2 K. TheH
c2
(0) values of Nb–Rh are in good agreement with the theoreticalH
c
2**
(0) values.Dedicated to Prof. Dr. W. Buckel on the occasion of his 60th birthday 相似文献
22.
H. L. Bay J. Bohdansky W. O. Hofer J. Roth 《Applied Physics A: Materials Science & Processing》1980,21(4):327-333
Angular differential and total sputtering yields of polycrystalline nickel and tungsten have been measured for 1 and 4 keV
H+ and 4 keV He+ ion bombardment at incidence angles between 0° and 80°. The differential sputtering yields (dY/dΩ) were determined with the aid of the collector technique, whereas the total yieldY was determined from the weight loss of the target during irradiation. Asymmetric angular distributions are observed at oblique
angles of incidence, the emission maximum being shifted in forward direction (with respect to the incident ions). Even more
pronounced than the change in shape of the emission distribution is an increase in the differential yield:dY/dΩ rises with increasing incidence angle over the whole range of ejection angles, the increase being most prominent in the
direction of primary recoil emission. This effect is therefore ascribed to emission of surface atoms in direct projectile-surface
atom collisions.
On short term leave from Institut für Plasmaphysik der Kernforschungsanlage Jülich GmbH, D-5170, Jülich, Fed. Rep. Germany. 相似文献
23.
A new electronical tuning process is proposed for a millimeterwave oscillator in slotline-technique. The circuit used for the GaAs-FET oscillator is realized by a slotline coupler-structure in which the feedback between the resonator and the transistor drain is made by help of electromagnetical field. 相似文献
24.
Ammar R Ball RC Banerjee S Bhat PC Bosetti P Bromberg C Canough GE Coffin T Dershem TO Dixon RL Fenker HC Ganguli SN Gensch U Girtler P Goshaw AT Grard F Gurtu A Hamilton C Henri VP Hernandez JJ Hrubec J Iori M Jones LW Kuhn D Knauss D Leedom ID Legros P Lemonne J Leutz H Liu X Malhotra PK Marraffino JM Mendez GE Miller R Naumann T Nguyen A Nowak H Pilette P Poirier J Poppleton A Raghavan R Rasner K Reucroft S Robertson WJ Roe BP Roth A Senko M Struczinski W Subramanian A Touboul MC Vonck B 《Physical review letters》1988,61(19):2185-2188
25.
Roth EH Hildebrand JA Wiggins SM Ross D 《The Journal of the Acoustical Society of America》2012,131(1):104-103
From September 2006 to June 2009, an autonomous acoustic recorder measured ambient noise north of Barrow, Alaska on the continental slope at 235 m depth, between the Chukchi and Beaufort Seas. Mean monthly spectrum levels, selected to exclude impulsive events, show that months with open-water had the highest noise levels (80-83 dB re: 1 μPa(2)/Hz at 20-50 Hz), months with ice coverage had lower spectral levels (70 dB at 50 Hz), and months with both ice cover and low wind speeds had the lowest noise levels (65 dB at 50 Hz). During ice covered periods in winter-spring there was significant transient energy between 10 and 100 Hz from ice fracture events. During ice covered periods in late spring there were significantly fewer transient events. Ambient noise increased with wind speed by ~ 1 dB/m/s for relatively open-water (0%-25% ice cover) and by ~ 0.5 dB/m/s for nearly complete ice cover (> 75%). In September and early October for all years, mean noise levels were elevated by 2-8 dB due to the presence of seismic surveys in the Chukchi and Beaufort Seas. 相似文献
26.
Th. Kuehl R. Bock S. Borneis E. Brambrink H. Brand J. Caird E. M. Campbell K. Cassou E. Gaul S. Goette C. Haefner T. Hahn H. M. Heuck D. H. H. Hoffmann D. Javarkova A. Klisnick H.-J. Kluge S. Kunzer T. Merz P. Neumayer P. Nickles M. D. Perry D. Reemts D. Ros M. Roth S. Samek W. Sandner G. Schaumann F. Schrader W. Seelig A. Tauschwitz R. Thiel D. Ursescu P. Wiewior U. Wittrock B. Zielbauer 《Hyperfine Interactions》2005,162(1-4):55-62
The high-energy high-power laser system PHELIX (Petawatt High Energy Laser for heavy Ion eXperiments) [1] is currently under construction at the Gesellschaft fuer Schwerionenforschung mbH (GSI) Darmstadt. With PHELIX GSI will
offer the unique combination of a high-current, high-energy (GeV/u) heavy-ion beam with an intense laser beam. This will open
the door to a variety of fundamental science issues in the field of atomic physics, plasma physics and nuclear physics. The
project will gain further interest in the near future by the dramatic increase of the accelerator performance with the starting
FAIR project at GSI [2]. This paper reports the current status of the project as well as the laser architecture. The proposed physics program and
a first experiment carried out with PHELIX, the realization of a transient collisionally excited x-ray laser [3], will also be reviewed briefly. 相似文献
27.
M. Roth M. Mehendale A. Bartelt H. Rabitz 《Applied physics. B, Lasers and optics》2005,80(4-5):441-444
This work demonstrates a simple method for ultraviolet (UV) acousto-optical pulse shaping of both spectral amplitude and phase. A fused-silica acousto-optical modulator is used to ensure high transmission and a high damage threshold at 400-nm center wavelength. The technique eliminates complications associated with the parametric transfer of the spectral phase of near-infrared pulses through a nonlinear process out to UV wavelengths, by separating the frequency doubling and shaping processes. Three illustrative applications of phase control are presented: the compensation of material dispersion, the generation of multiple pulse trains, and the generation of arbitrarily shaped pulse trains. Self-diffraction frequency-resolved optical gating is used to characterize the success of the technique. 相似文献
29.
30.
Paillet M Michel T Meyer JC Popov VN Henrard L Roth S Sauvajol JL 《Physical review letters》2006,96(25):257401
The resonant Raman spectra of (n, m) semiconducting single-walled carbon nanotubes, unambiguously identified from their electron diffraction patterns, have been measured. The diameter dependence of the frequency of the tangential modes with A symmetry has been obtained in the diameter range from 1.4 to 2.5 nm. The comparison between the excitation energies and the calculated transition energies allowed us to determine precisely the values of the Es33 and Es44 transition energies. Finally, in the debate concerning the dominant process at the origin of the first-order Raman scattering in single-walled carbon nanotubes (single resonance process or double resonance process), our results are well understood in the framework of a single resonance process. 相似文献