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941.
942.
943.
G. K. Ziyatdinova A. I. Samigullin G. K. Budnikov 《Journal of Analytical Chemistry》2007,62(8):773-776
Isoquinoline derivatives (papaverine and drotaverine) are oxidized at a graphite electrode in a 0.1 M sulfuric acid solution to give voltammetric waves at 1.1 V for papaverine and at 1.05 and 1.28 V for drotaverine. Determination limits and linearity ranges of currents as functions of papaverine and drotaverine concentrations are estimated. Microgram amounts of papaverine and drotaverine are determined in model solutions (RSD = 1–4%). A procedure for the direct determination of papaverine and drotaverine in pharmaceuticals is proposed. 相似文献
944.
The band spectrum of natural waves in a periodic structure formed by alternating dielectric and semiconductor layers is investigated
for the propagation of waves at some angle with respect to a magnetic field applied along the periodicity axis. A method is
presented for deriving a dispersion equation, and its properties are analyzed numerically. It is shown that, in the absence
of dissipation, there are two independent spectra of natural waves in the structure being considered, and the regions of existence
of various types of such waves are classified. It is established that the transmission bands of the two spectra may supplement
one another or overlap. It is found that, for the chosen magnetic-field direction, there exist numerous bands of transmission
of cyclotron waves. 相似文献
945.
Transverse flow transversely excited (TFTE) CO2 lasers are easily scalable to multikilowatt level. The laser power can be scaled up by increasing the volumetric gas flow
and discharge volume. It was observed in a TFTE CW CO2 laser having single row of pins as an anode and tubular cathode that the laser power was not increasing when the discharge
volume and the gas volumetric flow were increased by increasing the electrode separation keeping the gas flow velocity constant.
The discharge voltage too remained almost constant with the change of electrode separation at the same gas flow velocity.
This necessitated revision of the scaling laws for designing this type of high power CO2 laser. Experimental results of laser performance for different electrode separations are discussed and the modifications
in the scaling laws are presented. 相似文献
946.
947.
R. Arnaldi R. Averbeck K. Banicz J. Castor B. Chaurand C. Cicalo A. Colla P. Cortese S. Damjanovic A. David A. De Falco A. Devaux A. Drees L. Ducroux H. En’yo A. Ferretti M. Floris A. Foerster P. Force N. Guettet A. Guichard H. Gulkanian J. Heuser M. Keil L. Kluberg J. Lozano C. Lourenço F. Manso A. Masoni P. Martins A. Neves H. Ohnishi C. Oppedisano P. Parracho P. Pillot G. Puddu E. Radermacher P. Ramalhete P. Rosinsky E. Scomparin J. Seixas S. Serci R. Shahoyan P. Sonderegger H.J. Specht R. Tieulent G. Usai R. Veenhof H.K. Wöhri 《The European Physical Journal C - Particles and Fields》2007,49(1):235-241
The NA60 experiment at the CERN SPS has studied low-mass muon pairs in 158 A GeV In–In collisions. A strong excess of pairs
is observed above the yield expected from neutral meson decays. The unprecedented sample size close to 400000 events and the
good mass resolution of about 2% made it possible to isolate the excess by subtraction of the decay sources. The shape of
the resulting mass spectrum shows some non-trivial centrality dependence, but is largely consistent with a dominant contribution
from π+π-→ϱ→μ+μ- annihilation. The associated ϱ spectral function exhibits considerable broadening, but essentially no shift in mass. The
pT-differential mass spectra show the excess to be much stronger at low pT than at high pT. The results are compared to theoretical model predictions; they tend to rule out models linking hadron masses directly to
the chiral condensate.
PACS 25.75.-q; 12.38.Mh; 13.85.Qk 相似文献
948.
A. V. Boldashevskii Zh. K. Tukhmetova Sh. B. Kasenova S. M. Adekenov A. Nukhuly B. K. Kasenov A. M. Gazaliev S. D. Fazylov 《Russian Journal of Applied Chemistry》2006,79(10):1705-1708
Results of thermochemical studies of a new compound, potassium morpholinodithiocarbamate, are presented. The enthalpies of its solution in water at various dilutions and the specific heat at 173–348 K were examined by the experimental methods of isothermal and dynamic calorimetry. 相似文献
949.
E.Y. Kang Yoon B. Kim K.Y. Kim Y.H. Chung H.K. Baik 《Journal of magnetism and magnetic materials》2006
FeSiBNb amorphous powder cores were prepared with the amorphous powder by gas atomization and subsequent hot pressing of resulting powder after creating oxide layers on the amorphous powder. Fully amorphous FeSiBNb powders with good soft magnetic properties were successfully obtained in the particle size range below 100 μm. FeSiBNb amorphous powder cores exhibit stable permeability up to 10 MHz, showing excellent high-frequency characteristics. 相似文献
950.
A. Westphalen K. Theis-Bröhl H. Zabel K. Rott H. Brückl 《Journal of magnetism and magnetic materials》2006
We report on a magneto-optical Kerr effect (MOKE) investigation of alternating wide and narrow Fe bars, forming a two-dimensional periodic array. The magnetization reversal was studied by regular longitudinal Vector-MOKE in specular geometry as well as in Bragg-MOKE geometry, using the diffraction spots from the grating for hysteresis measurements. With Vector-MOKE a two-step switching process for the wide and narrow Fe bars is observed, indicative for a narrow switching field distribution in this array. In addition, hysteresis loops were determined as a function of the diffraction order for the hard and easy axis direction. The loops at different orders of diffraction can qualitatively and quantitatively be described by Fourier transformations of micromagnetic simulations. 相似文献