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911.
912.
Zero-free regions of thekth derivative of the Riemann zeta function ζ(k)(s) are investigated. It is proved that fork≥3, ζ(k)(s) has no zero in the region Res≥(1·1358826...)k+2. This result is an improvement upon the hitherto known zero-free region Res≥(7/4)k+2 on the right of the imaginary axis. The known zero-free region on the left of the imaginary axis is also improved by proving that ζ k)(s) may have at the most a finite number of non-real zeros on the left of the imaginary axis which are confined to a semicircle of finite radiusr k centred at the origin. 相似文献
913.
914.
K. Venugopalan K. C. Sebastian S. S. Sharma S. N. A. Jaffrey D. R. S. Somayajulu J. Verma 《Hyperfine Interactions》1987,34(1-4):239-242
The nuclear quadrupole interaction of Ta-181 in selenium was measured using perturbed angular correlation technique. The electric field gradient at room temperature is 4.56(32) × 1017 V/cm2. The temperature dependence of EFG follows the usual T3/2 behaviour. 相似文献
915.
This paper deals with the non-torsional oscillations of a disc in rotating second-order fluid. The disc and the fluid are initially in a state of rigid rotation and the non-torsional oscillations in its own plane are then imposed on the disc. The depth of penetration of the oscillations is increased due to the presence of the coefficient of visco-elasticity. It tends to infinity when the frequency of the oscillations is twice the angular velocity of rotation, meaning thereby that no equilibrium boundary layer exist. An initial value problem for two cases—(i) one disc bounding a semi-infinite mass of the fluid, (ii) two discs containing the fluid in between them is discussed. The classical Rayleigh layer for second-order fluid is derived as a particualr case and it is also found that steady Ekman layer is reached for large time. 相似文献
916.
IBr vapour was excited in the presence of argon by an uncondensed transformer discharge. Four band systems were obtained in the regions 5425–5360 Å, 4520–4415 Å, 4120–4010 Å and 3915–3540 Å of which the first three are discussed in this paper. The wavelengths and wavenumbers of the band heads in three systems as measured from the plates obtained with a 3-prism Steinheil glass spectrograph are given along with their visually estimated relative intensities. The three band systems, which are new, are analysed and the following vibrational constants expressed in cm.?1 are obtained:
相似文献
Band system | v e | w e ″ | w e ″x e ″ | w e ″y e ″ | w e ′ | w e ′x e ′ |
---|---|---|---|---|---|---|
5425-5360 Å | 18613 | 65·5 | 0·24 | ?0·01 | 43·0 | 0·026 |
4520-4415 Å | 22312 | 65·5 | 0·24 | ?0·01 | 77·0 | 0·5 |
4120-4010 Å | 24540 | 160·6 | 1·125 | .. | 128·4 | 0·1 |
917.
918.
Hong R Fischer NO Verma A Goodman CM Emrick T Rotello VM 《Journal of the American Chemical Society》2004,126(3):739-743
Thioalkyl and thioalkylated oligo(ethylene glycol) (OEG) ligands with chain-end functionality were used to fabricate water-soluble CdSe nanoparticle scaffolds. Surface recognition of chymotrypsin (ChT) was achieved using these functionalized nanoparticle scaffolds, with three levels of interaction demonstrated: no interaction (OEG terminated with hydroxyl group), inhibition with denaturation (carboxylate-terminated thioalkyl ligands), and inhibition with retention of structure (carboxylate-terminated OEG). The latter process was reversible upon an increase in ionic strength, with essentially complete restoration of enzymatic activity. 相似文献
919.
M. C. Rath S. K. Sarkar V. K. Wadhawan R. Verma I. M. L. Das R. Dąbrowski M. Tykarska R. Dhar 《Opto-Electronics Review》2008,16(4):399-403
Electron beam irradiation studies on liquid crystal material 5CB have been carried out at a temperature where the compound
exists in the isotropic liquid phase. In situ time-resolved spectroscopic characterization was carried out during the irradiation.
Three different transients were observed during the 2-μs electron pulse. After about 50 μs, only one transient species was
found to be present, which has an absorption peak at 360 nm. Radiolysed sample exhibits a broad absorption at ∼400 nm. The
dielectric measurements show that even a low level of irradiation results in a dramatic increase in the component of dielectric
permittivity normal to the long axes of the molecules ε⊥′, and a corresponding decrease in the dielectric anisotropy (Δε′=ε∥′−ε⊥′ ). These studies show that 5CB is prone to substantial radiation damage on exposure to the beam of high-energy electrons. 相似文献
920.
Magnetization of the ZnFe2O4 sample of average size 4 nm measured with SQUID in the temperature range 5–300 K shows anomalous behaviour in field cooled (FC) and zero-field-cooled (ZFC) conditions. The FC and ZFC curves measured in 50 Oe field cross each other a little before the peaks. No such anomaly is observed with samples of 6 nm particle size made with the same procedure. The characteristics of the FC and ZFC curves are very different in ZnFe2O4 samples of the same size (6 nm) made via two different chemical routes. The genesis of these differences are suggested to be in cationic configuration and spin disorder. Fe-extended X-ray absorption fine structure (EXAFS) studies show that there is around 80% inversion in case of zinc ferrite (ZnFe2O4) with the particle size 4 nm, whereas ZnFe2O4 of size 6 nm shows 40% inversion. The samples with an average particle size of 7 nm and more show negligible inversion. Theoretical simulations suggest that the electrostatic energy of the system plays a crucial role in deciding the cationic configuration of spinel ferrites. 相似文献