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1.
An assignment of the near-infrared bands in the 600–800 nm spectral region observed in magnetic circular dichroism (MCD)
spectra of high-spin ferrous haemoproteins is presented. The assignment is based on a relative energy level scheme for iron
d-electrons, a comparison of predicted and measured temperature dependences of MCD intensity, a sign of MCD bands and a group
theoretical analysis of allowed transitions. The proposed assignment is consistent with the ∼15-nm red shift of the ∼760 nm
band on breakage of the Fe-His bond in deoxy-myoglobin at low pH, with low-temperature photolysis experiments available for
CO complexes of several haemoproteins. In accordance with the observations, the intensity of the MCD bands for proteins with
a sulphur anion of cysteine as proximal haemligand (cytochrome P450 and chloroperoxidase) is predicted to be diminished by
at least one order of magnitude compared to that for proteins with an imidazole of a histidine as a protein-derived haemligand
(i.e. myoglobin, haemoglobin and horseradish peroxidase).
Received: 4 February 1997 / Accepted: 1 May 1997 相似文献
2.
Vasily L. Morgunov 《Pramana》2007,69(6):1097-1100
A new calorimeter energy calibration method was developed for the proposed ILC detectors. The method uses the center-of-mass
energy of the accelerator as the reference. It has been shown that using the energy conservation law it is possible to make
ECAL and HCAL cross calibration to reach a good energy resolution for the simple calorimeter energy sum.
相似文献
3.
Vasily Dzhordzhadze 《Acta Physica Hungarica A》2006,25(2-4):451-459
The PHENIX detector at RHIC has been designed to study different signatures of the states of matter created in heavy-ion collisions, and to investigate the spin structure of the nucleon. The PHENIX detector measures muons in two muon spectrometers, located at forward rapidities (1.2 < |η| < 2.4) and hadrons, electrons and photons in the two central spectrometers at midrapidity (|η| <0.35). To make a next step in the PHENIX research program, it is necessary to extend the rapidity coverage beyond the limits set by the existing central spectrometer. The functionality of the PHENIX muon detectors can be extended with added capabilities to measure photonic and hadronic jets. Tungsten calorimeters with silicon pixel readout and fine transverse and longitudinal segmentation are proposed to attain this goal. The proposed calorimeters will be located in the forward directions on either side of the PHENIX interaction point. In this talk we report on the studies of the functionality of the proposed calorimeters: the detector energy resolution, the jet reconstruction capabilities and the characteristics of pion rejection. 相似文献
4.
Presented at the International Conference on Contemporary Mathematical Problems in Mechanics and Their Applications (Moscow, November 11–15, 1987). 相似文献
5.
6.
Approximation by translates of refinable functions 总被引:23,自引:0,他引:23
Summary.
The functions
are
refinable if they are
combinations of the rescaled and translated functions
.
This is very common in scientific computing on a regular mesh.
The space of approximating functions with meshwidth
is a
subspace of with meshwidth
.
These refinable spaces have refinable basis functions.
The accuracy of the computations
depends on , the
order of approximation, which is determined by the degree of
polynomials
that lie in .
Most refinable functions (such as scaling functions in the theory
of wavelets) have no simple formulas.
The functions
are known only through the coefficients
in the refinement equation – scalars in the traditional case,
matrices for multiwavelets.
The scalar "sum rules" that determine
are well known.
We find the conditions on the matrices
that
yield approximation of order
from .
These are equivalent to the Strang–Fix conditions on the Fourier
transforms
, but for refinable
functions they can be explicitly verified from
the .
Received
August 31, 1994 / Revised version received May 2, 1995 相似文献
7.
8.
L. Ya. Gavrilova T. V. Aksenova L. A. Bannykh Ya. V. Teslenko V. A. Cherepanov 《Journal of Structural Chemistry》2003,44(2):248-251
Phase equilibria in the La–Sr–Co–Ni–O system were studied in air at 1100°. The samples for the study were synthesized by the standard ceramic and citrate processes. The limiting solubility and structure of La1-xSrxCo1-yNiyO3- and (La1-xSrx)2Co1-yNiyO4 solid solutions were determined by Xray powder diffraction analysis. La1-xSrxCo1-yNiyO3- solid solutions with 0 x 0.5 have a distorted rhombohedral perovskitelike structure (R
c space group). An increase in the strontium concentration reduces the rhombohedral distortions, and the compounds with x < 0.5 have an ideal cubic structure (Pm3m space group). (La1-xSrx)2Co1-yNiyO4 crystals have a tetragonal K2NiF4 type unit cell (I4/mmm space group). The relationships between unit cell parameters and compositions were obtained for singlephase La1-xSrxCo1-yNiyO3- and (La1-xSrx)2Co1-yNiyO4 samples. The existence regions of La1-xSrxCo1-yNiyO3- and La1-xSrx)2Co1-yNiyO4 solid solutions were distinguished on P–T phase diagrams. 相似文献
9.
An α-lithium derivative of 3-alkyl-substituted sydnone was first synthesized by direct metallation of 3-methyl-4-phenylsydnone withn-butyllithium. The reactivity of the compound obtained was studied. Reactions of 3-lithiomethyl-4-phenylsydnone with various electrophiles can serve as a convenient method for preparation of functionalized sydnones. 相似文献
10.
Cheesman MR Oganesyan VS Watmough NJ Butler CS Thomson AJ 《Journal of the American Chemical Society》2004,126(13):4157-4166
Fully oxidized cytochrome bo3 from Escherichia coli has been studied in its oxidized and several ligand-bound forms using electron paramagnetic resonance (EPR) and magnetic circular dichroism (MCD) spectroscopies. In each form, the spin-coupled high-spin Fe(III) heme o3 and CuB(II) ion at the active site give rise to similar fast-relaxing broad features in the dual-mode X-band EPR spectra. Simulations of dual-mode spectra are presented which show that this EPR can arise only from a dinuclear site in which the metal ions are weakly coupled by an anisotropic exchange interaction of J 1 cm-1. A variable-temperature and magnetic field (VTVF) MCD study is also presented for the cytochrome bo3 fluoride and azide derivatives. New methods are used to extract the contribution to the MCD of the spin-coupled active site in the presence of strong transitions from low-spin Fe(III) heme b. Analysis of the MCD data, independent of the EPR study, also shows that the spin-coupling within the active site is weak with J approximately 1 cm-1. These conclusions overturn a long-held view that such EPR signals in bovine cytochrome c oxidase arise from an S' = 2 ground state resulting from strong exchange coupling (J > 10(2) cm-1) within the active site. 相似文献