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191.
192.
Ohne Zusammenfassung 相似文献
193.
Johan M. Carlsson Helder S. Domingos Bo Hellsing Paul D. Bristowe 《Interface Science》2001,9(3-4):143-148
We have investigated Bi doping in the bulk and in a = 13 tilt grain boundary in ZnO using ab-initio DFT-calculations. We obtain a negative segregation energy suggesting that bismuth accumulates in the grain boundary. The Bi-atom causes considerable atomic displacements in the grain boundary increasing the local Bi–O bond length and attracting an O-atom on the opposite side of the structural unit in the grain boundary. The results suggest the formation of a Bi–rich phase in the grain boundary. The Bi-atoms act as donors and the conduction electrons are quasi-localised in the grain boundary region. 相似文献
194.
195.
F. Gouda G. Andersson S. T. Lagerwall K. Skarp B. Stebler T. Carlsson B.
ek C. Filipi
A. Levstik 《Liquid crystals》1989,6(2):219-230
The influence of a bias electric field on the temperature and frequency dependence of the soft mode part of the complex dielectric constant of the chiral smectic A* phase has been studied experimentally. It was found that only close to TS*CS*A does the bias field have any influence on the experimentally determined quantities. Here the relaxation frequency increased with increasing bias field, while the corresponding dielectric strength decreases. We also present a theoretical calculation of the influence of a bias field on the complex dielectric constant of the chiral smectic A* phase which, apart from minor details, is in accordance with the observed behaviour. Finally we discuss how the nature of the electroclinic effect can be correlated with the influence of the bias field on the smectic A* dielectric constant. 相似文献
196.
Abdel-Rehim M Carlsson G Bielenstein M Arvidsson T Blomberg LG 《Journal of chromatographic science》2000,38(10):458-464
Solid-phase microextraction (SPME) in combination with capillary gas chromatography and a nitrogen-phosphorous detector is used to study protein binding in human plasma samples. Local anesthetics of the amide-type (ropivacaine, bupivacaine, mepivacaine, prilocaine, and lidocaine) are used as model compounds in this evaluation. Carbowax/divinylbenzene (CW/DVB), polyacrylate, and polydimethylsiloxane fibers are tested. Sampling on CW/DVB fibers give the highest recovery in plasma samples compared with other fibers. Ultrafiltrate spiked with each of the substances is used for the construction of calibration curves. The protein binding is investigated at four different total concentrations from 0.5 to 15.0 microM. The degree of protein binding increases when the solute concentration decreases. Protein binding of the five solutes is investigated at four pH levels (6.4, 7.4, 8.4, and 9.4). It is found that protein binding increased with increasing pH. The influence of temperature variation (from 32 degrees C to 40 degrees C) on protein binding is also investigated. The protein binding decreases when the temperature increases. The methodology is validated and good correlation and precision are obtained. Back-calculated quality control samples give accuracy within 20% of theoretical values for all five substances. This study shows that SPME as a sample-preparation method gives the same protein binding for the studied local anesthetics as that achieved using earlier presented methods. 相似文献
197.
E. O. Lieder A. A. Pasternak R. M. Lieder A. D. Efimov V. M. Mikhajlov B. G. Carlsson I. Ragnarsson W. Gast Ts. Venkova T. Morek S. Chmel G. de Angelis D. R. Napoli A. Gadea D. Bazzacco R. Menegazzo S. Lunardi W. Urban Ch. Droste T. Rzaca-Urban G. Duchêne A. Dewald 《The European Physical Journal A - Hadrons and Nuclei》2008,35(2):135-158
For a level scheme investigation of 142Gd an experiment with the γ -spectrometer EUROBALLIII has been carried out and lifetimes have been measured with EUROBALL
IV using the Doppler-shift attenuation method. The high-spin states have been populated in these experiments by means of the
99Ru(48Ti, 2p3n) reaction at a beam energy of 240MeV and the 114Sn(32S, 2p2n) reaction at 160MeV, respectively. Reduced E2 transition probabilities B(E2) were determined for 15 members of four quadrupole bands. For the interpretation of the positive-parity even-spin quadrupole
bands, calculations in the cranked Nilsson-Strutinsky as well as interacting boson models have been performed. From the former
calculations it was concluded that the high-spin states of the (+ , 0)1 band in 142Gd represent a triaxial nucleus rotating around the longest principal axis. 相似文献
198.
199.
Hasse Carlsson Stephen Wainger 《Journal of Mathematical Analysis and Applications》1984,100(1):316-322
Let X be a random variable on Rn, n ? 2, having a density. Assume X has a finite exponential moment and non-zero mean vector, μ. Let ν be the corresponding renewal measure, and Q a cube. We obtain an asymptotic formula for ν(x + Q) as x → ∞ which is uniform in a small cone about the mean vector. This formula depends on moments of arbitrarily high order but depends only on the first and second moments of X in a region . 相似文献
200.
The problems of charge stripe formation, spin-charge separation, and stability of the antiphase domain wall (ADW) associated with a stripe are addressed using an analytical approach to the t- J(z) model. We show that a metallic stripe together with its ADW is the ground state of the problem in the low doping regime. The stripe is described as a system of spinons and magnetically confined holons strongly coupled to the two dimensional spin environment with holon-spin-polaron elementary excitations filling a one-dimensional band. 相似文献