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171.
The supersymmetric extension of theNUT–Kerr–Newman (NUT–KN)space–time is investigated. Along with fourstandard supersymmetries, this type of space–timeadmits fermionic symmetry generated by the square root of the bosonic constant of motion exceptthe Hamiltonian. Such a new supersymmetry corresponds tothe Killing–Yano tensor, which plays an importantrole in solving various field equations in thisspace–time. 相似文献
172.
Shyamal Kumar Chattopadhyay Mosarraf Hossain Saktiprosad Ghosh Arur Kumar Guha 《Transition Metal Chemistry》1990,15(6):473-477
Summary The chelating behaviour of two biologically active ligands, pyridine-2-carboxaldehyde(4-phenyl) thiosemicarbazone(L1H) and pyridine-2-carboxaldehyde thiosemicarbazone(LH), towards FeIII, CoIII, FeII and RhIII has been investigated. The ligands act as tridentate N–N–S donors, resulting in the formation of bis-chelate complexes of the type MIII(A)2X·nH2O (A=L1 or L; X=Cl, ClO4; M=CoIII, RhIII, FeIII), FeII(L1H)2SO4·2H2O and FeII(L1)2·H2O. Biological activity of the ligands and the metal complexes in the form ofin vitro antibacterial activities towardsE. coli has been evaluated and the possible reasons for enhancement of the activity of ligands on coordination to metal ion is discussed. 相似文献
173.
A buffer sharing scheme need to meet many competing objectives like robustness to changes in traffic conditions,fairness, efficiency, implementation simplicity, etc. Of the existing techniques, Push Out (PO) is optimum in terms of overall cell loss performance, but its delay performance is worse than that of all other methods for the multiple space priority. Another scheme named Dynamic Threshold (DT) is robust and adaptive which has good delay performance. A hybrid technique named Dynamic Threshold with native Push Out (DnP) shows the best delay performance but its loss performance is worse specially for higher priority traffic. A novel policy called Balanced Buffer Push Out (BBPO) is proposed here that aims to achieve a better loss performance than DT and better delay performance than PO for multipriority traffic. Using computer simulation the loss performance and delay performance of DT, PO, DnP and BBPO are measured for bursty traffic, and a comparison of the results is presented. The proposed scheme exhibits the best loss performance on an average among all the schemes. Although for higher priority traffic the loss performance of PO is better than that of BBPO, the delay performance of BBPO is better than that of PO. 相似文献
174.
The crystal and molecular structures of the title compound have been determined by single crystal X-ray diffraction methods. In the spiro molecule, the metal atom has a geometry very close to tetrahedral, with OTiO angles of 107.9–111.0(2)° and very short TiO bonds of length 1.777–1.791(5)Å. The two TiO5Si4 rings have different, ill-defined conformations; the SiO bond lengths and SiOSi angles are similar to those in (SiO)n rings. 相似文献
175.
We investigate the general relativistic magnetohydrodynamic (GRMHD) equations for cold plasma around the Reissner-Nordström black hole. Applying 3+1 spacetime split we linearize the perturbed equations for non-magnetized/magnetized plasma in both rotating and non-rotating background. By Fourier analyze we then derive dispersion relations and investigate the existence of waves with positive angular frequency in the vicinity of the black hole horizon. The analysis finds propagation of negative phase and group velocities for rotating magnetized surroundings. 相似文献
176.
Kang SO Hossain MA Powell D Bowman-James K 《Chemical communications (Cambridge, England)》2005,(3):328-330
Two crystal structures of sulfate inclusion complexes in an aza- and amido-cryptand represent the first examples of encapsulated sulfate in synthetic cryptand receptors and indicate penta- and octa-coordination, respectively. 相似文献
177.
Tanis JA Landers AL Pole DJ Alnaser AS Hossain S Kirchner T 《Physical review letters》2004,92(13):133201
Single- and double-electron transfer to autoionizing 1s2l2l(') configurations in fluorine ions have been investigated for 1.1 MeV/u collisions of F7+ and F8+ with He and Ne. The resulting Auger electron emission spectra show anomolously large intensities for the formation of the metastable 1s(2s2p 3P) 4P state compared to the similarly configured 1s(2s2p 3P) 2P- and 1s(2s2p 1P) 2P+ states. The large 4P intensity, which cannot be explained on the basis of spin statistics, is attributed instead to the Pauli exchange of similarly aligned electrons. 相似文献
178.
M.?N.?A.?Abdullah S.?Hossain M.?S.?I.?Sarker S.?K.?Das A.?S.?B.?Tariq M.?A.?Uddin A.?K.?BasakEmail author S.?Ali H.?M.?Sen Gupta F.?B.?Malik 《The European Physical Journal A - Hadrons and Nuclei》2003,18(1):65-73
A folding potential describing the
-scattering on 16O over a broad energy range 25.8-146.0 MeV is constructed on the basis of
-like cluster and unclustered-nucleon configurations of 16O. The resulting potential does not need any renormalization to fit the angular distribution of elastic cross-sections. The effects of the repulsive part of
-
and
-nucleon interactions are investigated. The analysis suggests that both the
-
repulsive potential and the unclustered nucleonic configuration in the target are important to describe the scattering data over a broad range of incident energies. The root-mean-square radius for the 16O nucleus is deduced.Received: 5 December 2002, Published online: 9 October 2003PACS:
25.55.Ci Elastic and inelastic scattering - 24.10.Ht Optical and diffraction models - 21.60.Gx Cluster models 相似文献
179.
The Klein-Gordon equation is applied to investigate superradiance around a dilatonic variant of dyonic black holes, a type of black holes whose extremal limits are justified for the S-wave approximation. The result is: The dilaton field boosts the superradiance. 相似文献
180.
The crystal and molecular structure of trimethyltin(IV) chloride, a chlorine-bridged, linear polymer
J. L. Lefferts K. C. Molloy M. B. Hossain D. van der Helm J. J. Zuckerman 《Journal of organometallic chemistry》1982,240(4):349-361
The crystal and molecular structure of trimethyltin(IV) chloride has been determined by the heavy-atom technique, and refined to a final R value of 0.041 for 1375 independent reflections (2θ < 53°; Mo-Ka radiation I > 2σ(I)) recorded at 138 ± 2 K on a Nonius CAD-4 counter diffractometer. The crystals are monoclinic with space group I2/c; a 12.541(8), b 9.618(11), c 11.015(11) Å, β 92.62(7)°, Z = 8, Dcalcd 1.994 g cm−3. The needle crystals are composed of polymeric chains of chlorine atoms bridging non-planar trimethyltin(IV) units at unequal (2.430(2) and 3.269(2) Å) distances. The zig-zag chains are bent at chlorine (angle Sn---Cl
Sn 150.30(9)°), but nearly linear at tin (angle Cl---Sn
Cl 176.85(6)°) to describe a distorted trigonal bipyramidal geometry at tin with the trimethyltin groups eclipsed. The interchain d(Sn
Cl) distances are greater than 4.1 Å. The angles carbon—tin—carbon (mean 117.1(3)°) are larger than tetrahedral, while the angles carbon—tin—chlorine (mean 99.9(2) Å) are smaller, in accord with isovalent hybridization principles, but more severely distorted than in the gas-phase, monomeric structure. The tin—chlorine distance of 2.430(2) Å is also longer than in the gas phase monomer, and the intermolecular contact of 3.269 Å is shorter than in other organotin chloride bridged systems (sum of Van der Waals radii 3.85 Å). 相似文献