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81.
Modified Stern-Volmer equation is obeyed by bovine serum albumin (BSA)-iodide system showing selective quenching of tryptophanyl
fluorescence of BSA. The fraction of accessible protein fluorescence is 0.56 and the effective Stern-Volmer constant is 290
M-1 at pH 7.4 in 0.005 M phosphate buffer at 25°C. Collisional quenching is operative both in the BSA -I−1 system and the model system, tryptophan-I−1. It is supported by the observed relationship between the ratio of quenching rate constants (k
q
) and diffusion coefficients and alsok
q
with bulk viscosity. 相似文献
82.
G. S. Kupriyanova 《Applied magnetic resonance》1996,11(1):87-97
A calculation of the complex signals in homonuclear correlation spectra (HOMCOR) of strongly coupled ABX three-spin systems is presented. It is shown that the presence of strong coupling causes the behavior of the cross-peaks to differ significantly from that found in the case of weak coupling. Two classes of connectivity patterns, namely weak and strong connectivity pairs of transitions are distinguished. Closed expressions for the real amplitudes are given. The dependence of the real amplitude on the flip angle of the mixing pulse and on the coupling strength is analyzed. 相似文献
83.
H. Grübmeier A. Naoumidis G. Stochniol A. Tsoga 《Fresenius' Journal of Analytical Chemistry》1995,353(3-4):393-398
Chemical interactions at the phase boundaries of materials applied for the solid oxide fuel cell (SOFC) have been studied by EPMA. The chemical reactivity at the interface of Lay-xSrxMnO3/ZrO2-Y2O3 is dependent on the stoichiometry (y) and the Sr content (x) of the perovskite. Typical reaction products (zirconates) and a diffusion zone in the ZrO2–Y2O3 have been observed. The extension of cation release (Mn) is related to the increasing chemical activity of Mn oxide in the perovskite by the Sr substitution for La. The wettability of the metal/oxide interface in the anode cermet (Ni/ZrO2–Y2O3) has been found to be influenced by chemical reactions resulting from the applied reducing atmosphere with high carbon activity. The disintegration of ZrO2–Y2O3 in contact with molten Ni or Ni-Ti and Ni-Cr alloys leads to the redeposition of Y2O3-enriched oxides and also to Zr-rich intermetallic compounds and eutectics. 相似文献
84.
W. A. Rodrigues Jr. Q. A. G. de Souza J. Vaz Jr. P. Lounesto 《International Journal of Theoretical Physics》1996,35(9):1849-1900
In this paper we study Dirac-Hestenes spinor fields (DHSF) on a four-dimensional Riemann-Cartan spacetime (RCST). We prove that these fields must be defined as certain equivalence classes of even sections of the Clifford bundle (over the RCST), thereby being certain particular sections of a new bundle named the spin-Clifford bundle (SCB). The conditions for the existence of the SCB are studied and are shown to be equivalent to Geroch's theorem concerning the existence of spinor structures in a Lorentzian spacetime. We introduce also the covariant and algebraic Dirac spinor fields and compare these with DHSF, showing that all three kinds of spinor fields contain the same mathematical and physical information. We clarify also the notion of (Crumeyrolle's) amorphous spinors (Dirac-Kähler spinor fields are of this type), showing that they cannot be used to describe fermionic fields. We develop a rigorous theory for the covariant derivatives of Clifford fields (sections of the Clifford bundle, CB) and of Dirac-Hestenes spinor fields. We show how to generalize the original Dirac-Hestenes equation in Minkowski spacetime for the case of RCST. Our results are obtained from a variational principle formulated through the multiform derivative approach to Lagrangian field theory in the Clifford bundle. 相似文献
85.
We propose an effective method of numerical determination of the gradient vector and the Hessian matrix of a quadratic quality
criterion in parametric optimization of continuous-discrete stochastic dynamic control systems based on the application of
adjoint equations.
Translated fromDinamicheskie Sistemy, No. 13, 1994, pp. 20–25. 相似文献
86.
87.
88.
P. G. Frayne 《International Journal of Infrared and Millimeter Waves》1992,13(5):713-720
At microwave frequencies, frequent use is made in circuit design of the electrical properties of short lengths of resistively terminated transmission line. It will be shown in the following contribution that circuits based on high frequency distributed lines can usefully be modelled at low audio frequencies using lumped element lines. 相似文献
89.
Silver nitrate-acetonitrile and π iodine-benzene complexes in thermotropic liquid crystals have been studied by 1H, 2H, and 13C NMR spectroscopy and by optical microscopy. Evidence for at least two silver complexes in each liquid crystal is presented. 相似文献
90.
A. R. Kuznetsov S. G. Lunter S. I. Nikitina A. G. Plyukhin Yu. K. Fedorov 《Journal of Applied Spectroscopy》1992,56(1):68-72
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 56, No. 1, pp. 90–95, January, 1992. 相似文献