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961.
Photosystem II core antenna of blue-green algae Synechococcus isolated in gel was studied by optical hole burning spectroscopy at 4·2 K. Persistent holes were burned into fluorescence spectra throughout the region 680–696 nm. The hole width extrapolated to zero burning fluence yielded a value 1·0±0·2 cm–1. A theoretical interpretation of the hole profile in fluorescence is presented. The dependence of saturated hole depth on burning wavelength is related to inhomogeneous site distribution function.Authors would like to thank F. Vácha from the Dept. of Biochemistry, Faculty of Nature Sciences, Charles University, for the preparation of the samples. 相似文献
962.
I.L. Lyubchanskii N.N. Dadoenkova M.I. Lyubchanskii E.A. Shapovalov A.E. Zabolotin K.Y. Guslienko T. Rasing 《Applied physics. B, Lasers and optics》2002,74(7-8):711-714
Nonlinear (at the second-harmonic frequency of the incident light) optical reflection by two-dimensional magnetic superstructures
is theoretically studied. A square lattice of magnetic dots and a hexagonal lattice of magnetic bubbles (cylindrical magnetic
domains) are considered. Because the periods of these structures are comparable with the wavelengths of the fundamental and
the second-harmonic radiation, it would be possible to observe diffraction at the second-harmonic frequency. A polarization
analysis of nonlinearly diffracted radiation is performed and the numbers of observable diffraction orders for the above structures
are estimated.
Received: 10 January 2002 / Published online: 11 June 2002 相似文献
963.
Our object of study is the asymptotic behavior of the sequence of polynomials orthogonal with respect to the discrete Sobolev
inner product <formula> \langle f, g \rangle = ∈t_{E} f(ξ) \overline{g(ξ)} ρ(ξ) |d ξ|+ f(Z) A g(Z)^H, </formula> where E is a rectifiable Jordan curve or arc in the complex plane
f(Z) = (f(z_1), \ldots, f^{(l_1)}(z_1) , \ldots , f(z_m) , \ldots ,f^{(l_m)}(z_m)),
A is an M \times M Hermitian matrix, M l
1
+ ⋅s + l
m
+ m , |d ξ| denotes the arc length measure, ρ is a nonnegative function on E , and z
i
∈Ω,
i=1,2,\ldots,m , where Ω is the exterior region to E .
July 23, 1999. Dates revised: September 11, 2000 and February 16, 2001. Date accepted: February 26, 2001. 相似文献
964.
It was studied the tin phase composition of the electrodeposited alloys produced at different temperatures and current densities from an acid chloride/fluoride electrolyte and an acid chloride bath. Mössbauer spectra were consistent with a Ni3Sn4 intermetallic compound, dissolved tin, and a Cu?Sn intermetallic compound formed at the interface of the copper substrate. 相似文献
965.
I Cserpan M Kalman M L Tj?rnhammar A Simoncsits 《Acta chemica Scandinavica (Copenhagen, Denmark : 1989)》1991,45(3):265-272
A general method to convert single-stranded, chemically synthesized oligonucleotides into cloned duplexes is described. Oligonucleotides supplied with 3'-terminal extensions that are complementary to 3'-protruding ends obtained by certain restriction enzymes can be cloned either directly or with the help of an adapter molecule into double-stranded vectors. Two methods have also been developed for consecutive cloning applications. According to these methods, the synthetic oligonucleotides (and their enzymatically prepared complementary strands) are joined, one after the other, inside a cloning vector, each joining requiring one cloning step. Synthetic genes are thus built up from oligonucleotides corresponding to only one strand of the DNA. The sequential assembly of the cloned duplex takes place in the 5' to 3' direction. Each oligonucleotide is supplied with a four-nucleotide-long 3'-terminal extension, but this sequence is eliminated when the joining takes place, leaving no limiting sequence between the oligonucleotides. The two consecutive cloning methods, the adapter and the polycloning site methods, are illustrated by the assembly of short artificial genes. 相似文献
966.
A simple and precise high performance liquid chromatographic method for the determination of mexiletine in human serum or plasma is described. Following addition of N-propionylprocainamide as internal standard the specimens are extracted, under basic conditions, into methylene chloride. After removal of the aqueous layer the drug is back-extracted into dilute acid, which is then injected directly for analysis. The extraction efficiency is 79% for both mexiletine and internal standard, and the assay is linear to 4 mg/L (twice upper therapeutic concentration). Inter-run coefficients of variation are 3.0% or less. The relative retention time of mexiletine to internal standard averages 1.3. An adaptation of this method is described for an alternate application to the analysis of tocainide, procainamide and N-acetylprocainamide. 相似文献
967.
Oscillatory change of pH occurs during the chromate-catalyzed decomposition of hydrogen peroxide in a weakly acidic medium at elevated temperature and at high initial concentration of hydrogen peroxide. In a closed system, there are only two or three periods, but sustained oscillation occurs in a CSTR. In a CSTR bistability is also found. In closed systems the temperature exhibits a great maximum (up to 15°C increase), in a CSTR sustained oscillation occurs at a constant stationary temperature. 相似文献
968.
969.
970.
Raskulova T. V. Volkova L. I. Danilevich Yu. S. Shainyan B. A. Khaliullin A. K. 《Russian Journal of Organic Chemistry》2002,38(5):754-755
Russian Journal of Organic Chemistry - 相似文献