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991.
One investigates a generalization of difference calculus and applies it to solve the functional equations of second order.
Presented at the 11th Colloquium “Quantum Groups and Integrable Systems”, Prague, 20–22 June 2002.
This work is supported in part by KBN grant 2 PO3 A 012 19. 相似文献
992.
Thermal analysis has been employed to measure changes of the heat capacity of ferromagnetic materials such as alloys in the region of the Curie temperature. Thermal response for these materials is usually small in this region. The necessary increase in sensitivity was achieved by applying temperature modulation. Results obtained by this technique including temperature-modulated differential thermal analysis simultaneously with A.C. thermomagnetometry are presented. 相似文献
993.
Low-field microwave absorption has been measured as a function of magnetic field in a series of thin film structures exhibiting or not exhibiting the giant magnetoresistance effect (GMR). Although a close correlation has been found between the microwave absorption and GMR, an additional absorption due to magnetization reversal is shown to have substantial effect on the overall microwave response. 相似文献
994.
J. Baszyński T. Toliński W. Kowalski A. Kowalczyk 《Czechoslovak Journal of Physics》2002,52(2):295-298
We studied the conductance of a point contact between a mechanically sharpened iron tip and a surface of the La0.7Sr0.3MnO3 perovskite electrode. The tip is fixed to a piezoelectric element and the conductance is measured as a function of the piezo voltage, which controls the tip pressing on the electrode. The height of steps between conductance plateaus is a multiple of the integer quantum e
2/h, characteristic for ferromagnetic materials in which the spin degeneracy is lifted. 相似文献
995.
Magnetic and transport properties of Tm2Co7B3 compound have been studied. This compound crystallizes in the hexagonal Ce2Co7B3 type structure. The coercivity (H
c) of the compound was determined from hysteresis measurements in fields up to 4 T. The temperature dependence of coercivity has been explained by a thermally activated process of domain wall motion. The resistivity at low temperatures shows a T
2 dependence. At higher temperatures the resistivity is not a linear function of temperature, which indicates an electron-phonon interaction in the presence of a small s-d scattering. 相似文献
996.
Soczewiński E 《Journal of chromatography. A》2002,965(1-2):109-116
The development of a simple molecular model of liquid-solid chromatography leading to linear logarithmic relationships between retention factor and eluent composition is discussed. Further evolution of the model and its practical applications in method development are reviewed. 相似文献
997.
An efficient synthesis of 13-epi-7-O-(triethylsilyl)baccatin III from 13-deoxybaccatin III is described. Oxidation of 13-deoxy-7-O-(triethylsilyl)baccatin III with tert-butyl peroxide, followed by reduction with SmI(2), produced 13-epi-7-O-(triethylsilyl)baccatin III in good overall yield. The preparation of 13-oxo-7-O-(triethylsilyl)baccatin III from 13-epi-7-O-(triethylsilyl)baccatin III using tetrapropylammonium perruthenate and N-methylmorpholine N-oxide is also reported. 相似文献
998.
Densities for DMSO solutions of iron(III), aluminium(III), beryllium(II) and magnesium(II) perchlorates and silver nitrate are reported. Densities for DMSO solutions of tetraethylammonium perchlorate and nitrate and tetrabutylammonium perchlorate and tetraphenylborate are also presented. The partial molar volumes of the DMSO-solvated cations are derived and discussed in terms of variation with the charge number. 相似文献
999.
Frański R Szymański A Gierczyk B Chlebicki J Frańska M 《Journal of mass spectrometry : JMS》2002,37(4):372-378
Liquid secondary ion (LSI) mass spectra of ion-pair precipitates obtained for Triton X-100 with strontium, lead, cadmium and mercury tetraphenylborates and for selected butoxylene-ethoxylene monoalkyl ethers with barium tetraiodobismuthate(III) are discussed. On the basis of LSI mass spectra, recorded in both positive and negative modes, the formulae of the ion-pair precipitates were determined. On the basis of B/E mass spectra, the fragmentation routes of [M - H + Ba](+) ions for butoxylene-ethoxylene monoalkyl ether complexes of barium and [M - H + Cd](+) ions for the Triton X-100 complex of cadmium are proposed. 相似文献
1000.
Z. Karczmarzyk D. Branowska A. Rykowski A. Fruziński 《Journal of chemical crystallography》2002,32(8):267-272
Title compound, C20H24N2S2, crystallizes in the orthorhombic system, space group Pbca, with cell constants a = 5.1968(5) Å, b = 15.6692(11) Å, c = 22.3881(11) Å , Z = 4, T = 293 K, Dcal = 1.299 g cm–3. The structure was solved by direct methods and refined to R value of 0.0465 for 1566 reflections. Two methylthio-octahydroisoquinoline parts of molecule are related by the center of symmetry and possess the trans conformation. This conformation is more energetically stable than cis but the molecule can rotate about the C(6)–C(6) central bond at room temperature (molecular mechanics calculations). There is a short intramolecular contact C(5)–H(51) N(1) in the molecule. The molecules in the crystal form molecular layers parallel to (001) crystallographic plane and the molecular packing is determined by the van der Waals forces only. 相似文献