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11.
Analysis of transmit-receive diversity in Rayleigh fading 总被引:4,自引:0,他引:4
We analyze the error performance of a wireless communication system employing transmit-receive diversity in Rayleigh fading. By focusing on the complex Gaussian statistics of the independent and identically distributed entries of the channel matrix, we derive a formula for the characteristic function (c.f.) of the maximum output signal-to-noise ratio. We use this c.f. to obtain a closed-form expression of the symbol error probability (SEP) for coherent binary keying. The method is easily extended to obtain the SEP for the coherent reception of M-ary modulation schemes. 相似文献
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Copper(II) complexes [Cu(ph-tpy)(B)](ClO4) (1–3), where ph-tpy is (4′-phenyl)-2,2′:6′,2″-terpyridine and B is N,N-donor phenanthroline base, viz. 1,10-phenanthroline (phen, 1), dipyridoquinoxaline (dpq, 2), and dipyridophenazine (dppz, 3), were prepared and characterized from analytical and spectral data. Complex 1, characterized by X-ray crystallography, shows a distorted square-pyramidal (4 + 1) CuN5 coordination geometry having the tridentate ph-tpy ligand at the basal plane and bidentate phen bound to the axial-equatorial sites. The complexes display a d–d band near 650 nm in aqueous DMF. The complexes are avid binders to calf thymus DNA giving the binding order: 3 (dppz) > 2 (dpq) > 1 (phen). The dpq and dppz complexes show photo-induced DNA cleavage activity in red light via photo-redox pathway forming hydroxyl radicals. The cytotoxicity of the dppz complex 3 was studied by MTT assay in HeLa cancer cells. The IC50 values are 3.7 and 12.4 μM in visible light of 400–700 nm and dark, respectively. 相似文献
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Debojyoti Lahiri Tuhin Bhowmick Bhabatosh Banik Reema Railkar Suryanarayanarao Ramakumar Rajan R. Dighe Akhil R. Chakravarty 《Polyhedron》2010
Dicobalt(II) complexes [{(B)CoII}2(μ-dtdp)2] (1–3) of 3,3′-dithiodipropionic acid (dtdp) and phenanthroline bases (B), viz. 1,10-phenanthroline (phen in 1), dipyrido[3,2-d:2′,3′-f]quinoxaline (dpq in 2) and dipyrido[3,2-a:2′,3′-c]phenazine (dppz in 3), have been prepared, characterized and their photo-induced anaerobic DNA cleavage activity studied. The elemental analysis and mass spectral data suggest binuclear formulation of the complexes. The redox inactive complexes have magnetically non-interacting dicobalt(II) core showing magnetic moment of ∼3.9 μB per cobalt(II) center. The complexes show good binding propensity to calf thymus DNA giving Kb values within 4.3 × 105–4.0 × 106 M−1. Thermal melting and viscosity data predict DNA groove binding and/or partial intercalative nature of the complexes. The complexes show significant anaerobic DNA cleavage activity in green light under argon atmosphere possibly involving radical species generated from the disulfide moiety in a type-I pathway. The DNA cleavage reaction under aerobic medium in green light is found to involve hydroxyl radical species. The dppz complex 3 exhibits significant photocytotoxicity in HeLa cervical cancer cells with an IC50 value of 2.3 μM in UV-A light of 365 nm, while it is essentially non-toxic in dark giving an IC50 value of >200 μM. A significant reduction of the dark toxicity of the organic dppz base (IC50 = 8.3 μM in dark) is observed on binding to the cobalt(II) center while essentially retaining its photocytotoxicity in UV-A light (IC50 = 0.4 μM). 相似文献
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The Energy Balance Principle (EBP) is well established for estimating the vibration levels of wind induced oscillations of single overhead transmission lines. The mathematical model, wherein a conductor is treated as a continuous system, results in a transcendental eigenvalue problem (EVP), which gives numerical difficulties in the case of bundled conductors. In this paper, different approaches for solving transcendental EVP and their relative merits are discussed. A new method named continuous spectrum approach provides a good engineering solution. Results from different approaches are compared. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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M. F. Horstemeyer J. Lathrop A. M. Gokhale M. Dighe 《Theoretical and Applied Fracture Mechanics》2000,33(1)
Internal state variable rate equations are cast in a continuum framework to model void nucleation, growth, and coalescence in a cast Al–Si–Mg aluminum alloy. The kinematics and constitutive relations for damage resulting from void nucleation, growth, and coalescence are discussed. Because damage evolution is intimately coupled with the stress state, internal state variable hardening rate equations are developed to distinguish between compression, tension, and torsion straining conditions. The scalar isotropic hardening equation and second rank tensorial kinematic hardening equation from the Bammann–Chiesa–Johnson (BCJ) Plasticity model are modified to account for hardening rate differences under tension, compression, and torsion. A method for determining the material constants for the plasticity and damage equations is presented. Parameter determination for the proposed phenomenological nucleation rate equation, motivated from fracture mechanics and microscale physical observations, involves counting nucleation sites as a function of strain from optical micrographs. Although different void growth models can be included, the McClintock void growth model is used in this study. A coalescence model is also introduced. The damage framework is then evaluated with respect to experimental tensile data of notched Al–Si–Mg cast aluminum alloy specimens. Finite element results employing the damage framework are shown to illustrate its usefulness. 相似文献
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Debajyoti Choudhury Rahul Sinha S Arunagiri Gautam Bhattacharyya Debrupa Chakraverty Debajyoti Choudhury Amitava Datta Anindya Datta Aseskrishna Datta Amol Dighe Dilip Kumar Ghosh Anjan Giri Stephen King Anirban Kundu Rukmani Mohanta Biswarup Mukhopadhyaya Sreerup Raychaudhuri Saurabh Rindani Probir Roy DP Roy Sourov Roy AI Sanda Nita Sinha Rahul Sinha K Sridhar H Yamamoto 《Pramana》2000,55(1-2):335-345
This report summarises the work done during WHEPP-6 (Institute of Mathematical Sciences, Chennai, India, Jan 3–15, 2000) in
Working group on ‘B and collider physics’. 相似文献
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M. F. Horstemeyer Ken Gall K. W. Dolan A. Waters J. J. Haskins D. E. Perkins A. M. Gokhale M. D. Dighe 《Theoretical and Applied Fracture Mechanics》2003,39(1):23-45
Void nucleation, growth, and coalescence in A356 aluminum notch specimens was determined from a combination of experiments, finite element analysis, nondestructive analysis, and image analysis. Notch Bridgman tension experiments were performed on specimens to failure and then other specimens were tested to 90%, 95%, and 98% of the failure load. The specimens were evaluated with nondestructive X-ray tomography and optical image analysis. Finite element simulations of the notch tests were performed with an elastic–plastic internal state variable material model that incorporated the pertinent microstructures (silicon particle volume fraction and size distribution and porosity volume fraction and size distribution). Parametric finite element simulations were performed to give insight into various initial conditions and responses of the notch tensile bars. The various methods all corroborated the same damage progression. 相似文献