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471.
Malcolm H. Chisholm Christopher M. Hadad Katja Heinze Klaus Hempel Namrata Singh Shubham Vyas 《Journal of Cluster Science》2008,19(1):209-218
The homoleptic compound Ru(II)(L)2 where L = 4′-carboxylato-2,2′:6′,2″-terpyridine was employed as a bridge to link two [Mo2(O2CBu
t
)3]+ units in the formation of the title complex: [Mo2(O2CBu
t
)3]2-μ-Ru(II)L2] (2+) [BF4−]2, which has been characterized by 1H-NMR, UV–vis and emission spectroscopy, MALDI-TOF-MS and cyclic voltammetry. The electronic structure of the complex has
been investigated by density functional theory employing Turbomole on the model complex cation [Mo2(O2CH)3]2-μ-(Ru(II)L2)2+. The intense blue color of the cation arises from M2 δ to bridge/terpyridine charge transfer.
This paper is dedicated to Prof. F. A. Cotton in memoriam. 相似文献
472.
Activated polystyrene cuvet is used for the determination of oxalate in urine sample and immunoglobulin in human sera. Polystyrene cuvet was activated by introducing active functional group onto its surface by coating the surface with a heterobifunctional photolinker, 1-fluoro-2-nitro-4-azidobenzene and exposing to UV light at 365 nm. Modified cuvet was active enough to covalently link oxalate oxidase in just 45 min at 50 °C without any additional catalyst or reagent. Remarkable reduction of time was achieved when immobilization was carried out by microwave irradiation. It took only 50 s to immobilize oxalate oxidase in the activated cuvet when exposed to microwaves in a domestic microwave oven. Immobilized-oxalate oxidase was stable, reusable and conveniently used for determination of urinary oxalate for diagnosis of primary hyperoxaluria and calcium oxalate nephrolithaiasis. Detection of human IgG involving ELISA in antihuman IgG-immobilized cuvet showed the feasibility of the cuvet in other immunoassays. 相似文献
473.
Quantum communication with terahertz (THz) frequency signals has many advantages like reduced attenuation and scintillation effects in certain atmospheric conditions along with very high level of data security. In this work, we propose a scheme to realize Quantum Memory (QM) for efficient storage of terahertz (THz) frequency signals using Electromagnetically Induced Transparency (EIT) in an ultracold atomic medium of 87Rb Rydberg atoms prepared in a Two Dimensional Magneto Optical Trap (2D-MOT). The uniqueness of our scheme lies in the choice of the energy levels involved in the EIT process, all three of which have been chosen to be the Rydberg levels (enabling signal beam to be in THz) in a lambda type arrangement. This first of its kind proposal reveals that atomic media are a potential candidate for devising QMs which can store THz frequency signals. We have estimated that the Optical Depth (OD) in our scheme can reach a very high value of 690, very high maximum obtainable storage efficiency (η) of ~99%, the group velocity () can be as low as 5.07 × 103 m/s, and the Delay Bandwidth Product (DBP) can be as high as 9.5. All of these estimates emphasize the feasibility of our scheme as a QM device for efficient storage of THz pulses. 相似文献
474.
N. R. Soni B. R. Joshi R. P. Shah H. R. Chauhan J. N. Pandya 《The European Physical Journal C - Particles and Fields》2018,78(7):592
The mass spectra and decay properties of heavy quarkonia are computed in nonrelativistic quark-antiquark Cornell potential model. We have employed the numerical solution of Schrödinger equation to obtain their mass spectra using only four parameters namely quark mass (\(m_c\), \(m_b\)) and confinement strength (\(A_{c\bar{c}}\), \(A_{b\bar{b}}\)). The spin hyperfine, spin-orbit and tensor components of the one gluon exchange interaction are computed perturbatively to determine the mass spectra of excited S, P, D and F states. Digamma, digluon and dilepton decays of these mesons are computed using the model parameters and numerical wave functions. The predicted spectroscopy and decay properties for quarkonia are found to be consistent with available data from experiments, lattice QCD and other theoretical approaches. We also compute mass spectra and life time of the \(B_c\) meson without additional parameters. The computed electromagnetic transition widths of heavy quarkonia and \(B_c\) mesons are in tune with available experimental data and other theoretical approaches. 相似文献
475.
Narendra Chauhan Ankush Mittal Dietmar Wagner M. V. Kartikeyan M. K. Thumm 《International Journal of Infrared and Millimeter Waves》2008,29(8):792-798
In this paper the design and optimization of a nonlinear diameter taper, connecting the output section of a gyrotron cavity
to the uniform output waveguide section, is presented. The design of a nonlinear taper of a 42 GHz, 200 kW CW gyrotron operating
in the TE0,3 cavity mode with axial output collection has been taken as a case study. The taper synthesis has been carried out considering
a raised cosine type of nonlinear taper and the analysis is done using a dedicated scattering matrix code. In addition, an
improved particle swarm optimization - an evolutionary optimization - algorithm is used for the design optimization of this
nonlinear taper. The optimum design of the taper shows the effectiveness of the presented method. 相似文献
476.
477.
Namrata Ashutosh Bhardwaj Kirti Ranjan Sudeep Chatterji Ajay K. Srivastava V.K. Verma R.K. Shivpuri 《The European Physical Journal A - Hadrons and Nuclei》2002,13(4):405-410
Multiplicity distributions of charged particles produced in interactions of 800 GeV protons with emulsion nuclei in various
rapidity windows are presented. The data is also analyzed separately for the forward and the backward hemispheres, for rapidity
windows of different widths. It is found that the Negative Binomial Distribution (NBD) describes well the multiplicity distribution
of secondary particles in various rapidity windows and also in both the hemispheres. We have compared the NBD parameters,
in both the hemispheres, at 200 GeV and 360 GeV, with those at 800 GeV. The behaviour of NBD parameters in rapidity windows
of different widths and for different targets has also been studied.
Received: 30 August 2001 / Accepted: 28 January 2002 相似文献
478.
The biomimetic oxidation of curcumin, a main turmeric pigment with hydrogen peroxide catalyzed by different 5,10,15,20-tetraarylporphyrinatoiron(III) chlorides [TAPFe(III)Cl] in dichloromethane has been studied to give a C-C coupled curcumin dimer in 40-70% yield. The structure of the dimer has been elucidated by (1)H-, (13)C-NMR, IR and FAB-Mass spectroscopic data. 相似文献
479.
XANES and EXAFS techniques are proving very popular in the study of local environment in disordered systems. Results of such
studies in a large number of metal (Fe, Co, Ni, etc)-metalloid (B, Si, C, etc) glasses are reported. Experiments were done
with synchrotron radiation as well as an x-ray tube. The values of bond lengths and co-ordination numbers computed from one-electron
single scattering Fourier transform method turn out substantially smaller. The values of bondlength determined from the other
EXAFS calculation method and the multiple-scattering computation scheme show good agreement. Importance of choice of suitable
reference materials for analysis of data is emphasized.
The experimental work was done at EXAFS 5.1 Station at Daresbury Laboratory, U.K. 相似文献
480.