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101.
High bit-rate (>10 Gb/s) signals are composed of very short pulses and propagation of such pulses through a semiconductor
optical amplifier (SOA) requires consideration of intraband phenomena. Due to the intraband effects, the propagating pulse
sees a fast recovering nonlinear gain which introduces less distortion in the pulse shape and spectrum of the output pulse
but introduces a positive chirping at the trailing edge of the pulse. 相似文献
102.
We use an iteration scheme to approximate common fixed points of nearly asymptotically nonexpansive mappings.We generalize corresponding theorems of [1] to the case of two nearly asymptotically nonexpansive mappings and those of [9] not only to a larger class of mappings but also with better rate of convergence. 相似文献
103.
Effect of denaturation of DNA on the molecular organization of a fluorescent dye in ultra thin films
Acridine Orange (AO) forms H-dimer in solid state and in ultra thin films. However, H dimer of AO reduces its efficiency as a usefull material for fluorescence probe. In the present work detailed investigations has been done on the interaction of AO with different forms of DNA in order to check the effectiveness in controlling the dimeric sites of AO in the Layer by Layer (LbL) self assembled film. It was found that single stranded DNA (ssDNA) is most effective than the dsDNA and coil-shaped DNA in controlling the dimeric sites of AO in LbL film. 相似文献
104.
Affolder T Akimoto H Akopian A Albrow MG Amaral P Amidei D Anikeev K Antos J Apollinari G Arisawa T Artikov A Asakawa T Ashmanskas W Azfar F Azzi-Bacchetta P Bacchetta N Bachacou H Bailey S de Barbaro P Barbaro-Galtieri A Barnes VE Barnett BA Baroiant S Barone M Battle C Bauer G Bedeschi F Belforte S Bell WH Bellettini G Bellinger J Benjamin D Bensinger J Beretvas A Berge JP Berryhill J Bhatti A Binkley M Bisello D Bishai M Blair RE Blocker C Bloom K Blumenfeld B Blusk SR Bocci A Bodek A 《Physical review letters》2002,88(7):071806
We present the first general search for new heavy particles, X, which decay via X --> WZ0 --> e(nu)+jj as a function of M(X) and Gamma(X) in pp collisions at square root[s] = 1.8 TeV. No evidence is found for production of X in 110 pb(-1) of data collected by the Collider Detector at Fermilab. General cross section limits are set at the 95% C.L. as a function of mass and width of the new particle. The results are further interpreted as mass limits on the production of new heavy charged vector bosons which decay via W' --> WZ0 in an extended gauge model as a function of the width, Gamma(W'), and mixing factor between the W' and the standard model W bosons. 相似文献
105.
Bogdanov PV Lanzara A Zhou XJ Yang WL Eisaki H Hussain Z Shen ZX 《Physical review letters》2002,89(16):167002
The question of the anisotropy of the electron scattering in high temperature superconductors is investigated using high resolution angle-resolved photoemission data from Pb-doped Bi2Sr2CaCu2O8 (Bi2212) with suppressed superstructure. The scattering rate of low energy electrons along two bilayer-split pieces of the Fermi surface is measured (via the quasiparticle peak width), and no increase of scattering towards the antinode (pi,0) region is observed, contradicting the expectation from Q=(pi,pi) scattering. The results put a limit on the effects of Q=(pi,pi) scattering on the electronic structure of this overdoped superconductor with still very high T(c). 相似文献
106.
M. Sakhawat Hussain 《Journal of chemical crystallography》1986,16(1):91-99
The crystal and molecular structures of chloro(triphenylphosphineselenide)gold(I), [(C6H5)3PSe]AuCl, have been determined from three-dimensional X-ray intensity data collected on a CAD4 diffractometer. The compound crystallizes in the triclinic space groupPl witha=9.322(3),b=10.639(5),c=9.252(3) Å, =104.74(4), =99.52(3), =76.97(3)°, andZ=2. Atomic parameters were refined by full-matrix least-squares to anR value of 5.7% for 2591 observed reflections. This is one of the few known examples of linear gold(I) complexes having an Au-Se linkage. The Se-Au-Cl angle is 178.6(1)°, and the Au-Se and Au-Cl distances are 2.371(2) and 2.277(6) Å, respectively. As expected, the Au-Se bond length is 0.10–0.18 Å longer than the Au-S bond length observed in similar two-coordinate linear gold(I) complexes. 相似文献
107.
(+)-Parviflorine (), found in Lam. (Fumariaceae), is the first known glycosidic spirobenzylisoquinoline alkaloid. Its acid hydrolysis yields (+)-parfumine () and D-glucose. Klyne's rule indicates that is a β-D-glucoside. The absolute configuration shown in expressions is predominant among spirobenzylisoquinolines. A generalization has been drawn between plant source and the oxygenation pattern of ring C for the spirobenzylisoquinoline alkaloids. 相似文献
108.
Ahmad VU Hussain J Hussain H Farooq U Farmanullah Lodhi MA Choudhary MI 《Natural product research》2005,19(3):267-274
Two new myrsinol-type diterpene polyesters 3,5,13,17-tetra-O-acetyl-7-O-benzoyl-15-hydroxymyrsinol (1) and 3,5,13,17-tetra-O-acetyl-7-O-butanoyl-13-hydroxymyrsinol (2), with a tricyclic carbon skeleton have been isolated from Euphorbia decipiens Boiss. & Buhse. The structure elucidation of the isolated compounds was based primarily on HREIMS, EIMS, IR, UV, ID-, and 2D-NMR analyses, including COSY, HMQC, HMBC, and NOESY correlations. Compounds 1 and 2 also showed activity against urease enzyme. 相似文献
109.
Rösch O Gunnarsson O Zhou XJ Yoshida T Sasagawa T Fujimori A Hussain Z Shen ZX Uchida S 《Physical review letters》2005,95(22):227002
We present angle-resolved photoemission spectroscopy (ARPES) data on undoped La2CuO4, indicating polaronic coupling between bosons and charge carriers. Using a shell model, we calculate the electron-phonon coupling and find that it is strong enough to give self-trapped polarons. We develop an efficient method for calculating ARPES spectra in undoped systems. Using the calculated couplings, we find the width of the phonon sideband in good agreement with experiment. We analyze reasons for the observed dependence of the width on the binding energy. 相似文献
110.
Hussain HA Ansari AA Iftikhar K 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2004,60(4):873-884
The optical absorption and NMR studies of trivalent lanthanide chloride complexes with 2,2'-bipyridine (bpy) are presented and discussed. The NMR spectra of paramagnetic complexes exhibit lower as well as higher field shifts of bpy resonances that reflect change in geometry and reveals importance of the factor (3 cos2 theta - 1 ) in changing sign of the shift. The paramagnetic shifts recorded have been analyzed and the intramolecular shift ratios suggest that the paramagnetic shift is predominantly dipolar in origin. Electronic spectral studies of the Pr, Nd, Ho, Er and Dy complexes in different solvents (viz. methanol, pyridine, DMSO and DMF), which differ with respect to donor atoms, reveal that the chemical environment around the lanthanide ion has great impact on f-f transitions and any change in the environment results in modifications of the spectra. The oscillator strength for the hypersensitive and non-hypersensitive transitions have been determined and changes in the oscillator strength and band shape with respect to solvent type is rationalized in terms of ligand (solvent) structure and coordination properties. 相似文献