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51.
N-[1-Alkylpyridin-4(1H)-ylidene]amides (PYAs) are a new class of easily prepared, neutral N-donor ligands that share some features in common with N-heterocyclic carbenes. They are strongly electron-donating toward metal centers, and a palladium(II) complex of one of these ligands has been shown to successfully catalyze both the Heck-Mizoroki and Suzuki-Miyaura cross-coupling reactions. 相似文献
52.
Shahid Hussain Arshad Muhammad Nawaz Naeem Nazra Sultana Zafar Iqbal Abdul Ghafar Shah 《Archive of Applied Mechanics (Ingenieur Archiv)》2011,81(8):999-1016
In the present work, vibration characteristics of thin functionally graded cylindrical shells are studied under the influence
of various boundary conditions. Fabrication of FGM cylindrical shell is carried out by using exponential volume fraction law.
Strain- and curvature-displacements relationships are taken from Love’s thin shell theory. The frequency equation in the form
of eigenvalue problem is obtained by adapting the Rayleigh-Ritz method. Characteristic beam functions are assumed to approximate
the axial modal dependence. Effects of exponential volume fraction law on the natural frequencies of the FGM cylindrical shells
for various boundary conditions are studied against circumferential wave number, length to radius ratio and thickness to radius
ratio for different values of power law exponents. Results evaluated show good agreement with those available in the literature. 相似文献
53.
Dark transient capacitance measurements have been used to investigate the deeplevel content of red GaP LEDs. Thermal emission rate data is obtained and the 0.75 eV “killer” centre is identified from the signature. 相似文献
54.
55.
56.
A Raman scattering study of the pressure induced phase transition in thallium azide is discussed. The transition appears to be triggered by the softening of a mode at 33 cm?1, which is shown by a Green's function calculation to be anharmonically coupled to another mode of the same symmetry at 48 cm?1. 相似文献
57.
Choudhary MI Musharraf SG Siddiqui ZA Khan NT Ali RA Ur-Rahman A 《Chemical & pharmaceutical bulletin》2005,53(8):1011-1013
The microbial transformation of an oral contraceptive, mestranol (1) by Cunninghamella elegans yielded two hydroxylated metabolites, 6beta-hydroxymestranol (2) and 6beta,12beta-dihydroxymestranol (3). Metabolite 3 was found to be a new compound. These metabolites were structurally characterized on the basis of spectroscopic techniques. 相似文献
58.
A model for multiparticle production process in high-energy hadronic collisions is proposed. In the centre of mass (CM) system
of colliding particles the target and the projectile are assumed to pass through each other sharing energies allowed by kinematical
constraints. Thus in app collision the energy associated with each is √S/2 (S being the square of the CM energy) which is taken to be the real variable that governs the number of particles produced.
In the case of hadronnucleus collisions the projectile and the target ofv nucleons lying in a (Lorentz contracted) tube pass through each other sharing energies ⋍ √S
A2, whereS
A ⋍vS. Before the final state particles emerge from these systems, the constituents of the target, i.e.,v nucleons share equally (= √S
A2v) the total energy associated with the target and become the centres from which final state particles stem out. Several results
have been discussed. 相似文献
59.
Thermal degradation of PVC in various solvents at 180° has been observed to be in the following order: benzonitrite > nitrobenzene > cyclohexanone > dioctyl phthalate > α-bromonaphthalane > decahydronaphthalene. The effect has been explained on the basis of β-eliminations of E1-type favoured by polar solvents. An inhibition in PVC degradation has been observed in nitrobenzene containing stationary hydrogen chloride gas. The deceleration in degradation by predissolved HCl has been accounted for as a Mass Law effect. 相似文献
60.
P.P. Hankare R.P. Patil U.B. Sankpal R. Sasikala I.S. Mulla 《Journal of magnetism and magnetic materials》2010,322(18):2629-9662
Nanocrystalline Li0.5Fe2.5−xCrxO4 (2.5≤x≥0) ferrites were prepared by a sol-gel autocombustion route. X-ray diffraction was employed to confirm the cubic spinel phase formation of the ferrites. The lattice parameter decreases with increase in Cr content. The saturation magnetization, coercivity and remanance were studied as a function of Cr content. The dielectric constant and dielectric loss were measured as a function of frequency in the frequency range 20 Hz-1 MHz. Frequency dependence of dielectric constant shows dielectric dispersion due to the Maxwell-Wagner type of interfacial polarization. In order to understand the conduction mechanism, complex impedance measurements were carried out. The substitution of chromium plays an important role in changing the dielectric and magnetic properties of lithium ferrites. 相似文献