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1.
Heavy ion irradiation in the electronic stopping power region induces macroscopic dimensional change in metallic glasses and introduces magnetic anisotropy in some magnetic materials. The present work is on the irradiation study of ferromagnetic metallic glasses, where both dimensional change and modification of magnetic anisotropy are expected. Magnetic anisotropy was measured using Mössbauer spectroscopy of virgin and irradiated Fe40Ni40B20 and Fe40Ni38Mo4B18 metallic glass ribbons. 90 MeV 127I beam was used for the irradiations. Irradiation doses were 5×1013 and 7.5×1013 ions/cm2. The relative intensity ratios D 23 of the second and third lines of the Mössbauer spectra were measured to determine the magnetic anisotropy. The virgin samples of both the materials display in-plane magnetic anisotropy, i.e., the spins are oriented parallel to the ribbon plane. Irradiation is found to cause reduction in magnetic anisotropy. Near-complete randomization of magnetic moments is observed at high irradiation doses. Correlation is found between the residual stresses introduced by ion irradiation and the change in magnetic anisotropy. 相似文献
2.
D.C. Lankin G.W. Griffin I. Bernal J. Korp S.F. Watkins T.J. Delord N.S. Bhacca 《Tetrahedron》1984,40(15):2829-2836
Condensation of 2,5,5-trimethylhexa-2,3-dien-6-a1 with malononitrile affords an unexpected product, C15H16N4X, (), the structure of which was partially characterized by spectral (infrared, ultraviolet, 1H, and 13C nmr) methods and fully elucidated by single crystal X-ray analysis. is l-cyano-2-amino-3-(2-propenyl)-5,5-dimethy-6- dicyanomethycycohexa-l,3-diene in a half-chair conformation. Conjugation of the -aminocyanoethenyl moiety leads to intermolecular hydrogen bonding in the crystal. A reaction sequence and its mechanistic implications are proposed. 相似文献
3.
4.
5.
In subnormal glow discharge under d.c. excitation at different pressure in a varying transverse magnetic field (0 to 30 G)
some measurements have been carried out for various initial average tube currents. The voltage across the discharge increases
and average tube current and residual current decreases in the magnetic field. With the help of Beckman’s expression [4] for
the axial field and the electron density distribution in a transverse magnetic field the observed variation of current and
voltage can be satisfactorily explained. The variation of axial electric field with transverse magnetic field can be represented
to a fair degree of accuracy by the derived equation. The behaviour of residual current with magnetic field has been observed
in these oscillations. 相似文献
6.
7.
G.W. Griffin D.C. Lankin N.S. Bhacca H. Terasawa R.K. Sehgal 《Tetrahedron letters》1982,23(27):2753-2756
Oxaziridines are proposed as intermediates in the photoinduced cycloadditions of electron deficient nitrones to dipolarophiles. 相似文献
8.
A. V. Lankin I. V. Morozov G. É. Norman I. Yu. Skobelev 《Journal of Experimental and Theoretical Physics》2008,106(3):608-622
A plasma model of relaxation of a medium in heavy-ion tracks in condensed matter has been proposed. The model is based on the solution of time-dependent equations of radiative-collisional kinetics. The state of the medium, which is described in the framework of the classical model of multiple ionization of target atoms by a field of fast multiply charged ions, is used as the initial condition. The relaxation in the plasma is investigated using molecular dynamics simulation. An analysis of the results of the calculations performed has made it possible to determine the range of material parameters at which the plasma model actually changes over to the atomic model and to establish the conditions where the atomic model is a very rough approximation. It is demonstrated that the plasma model adequately describes the X-ray spectra recorded upon interaction of ion beams with condensed targets. An X-ray spectral method based on the plasma model is proposed for diagnosing the plasma in fast-ion tracks. The results obtained can be useful in examining the initial stage of defect formation in solids under irradiation with single fast heavy ions. 相似文献
9.
In the present paper, a training algorithm with nontraditional capabilities and self-adaptation is suggested for a new generation
of neural networks with search behavior. The results obtained open up new opportunities for progress in the physics of living
systems in the direction of modeling of purposeful search behavior at the insect level. They enable systems of adaptive control,
considering changes in environmental conditions and in properties of the controllable object in the control process, to be
developed. The algorithm allows both traditional supervisory training of a neural network with a priori known answers and
finish learning during its functioning in accordance with preassigned criteria when knowledge of required states of neuron
network outputs is lacking.
Krasnoyarsk State University; Institute of Biophysics of the Siberian Branch of the Russian Academy of Sciences. Translated
from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 47–51, June, 2000. 相似文献
10.
DC Muddiman AP Null JC Hannis 《Rapid communications in mass spectrometry : RCM》1999,13(12):1201-1204
Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICRMS) has been used to determine the mass of a double-stranded 500 base-pair (bp) polymerase chain reaction (PCR) product with an average theoretical mass of the blunt-ended (i.e. unadenylated) species of 308 859.35 Da. The PCR product was generated from the linearized bacteriophage Lambda genome which is a double-stranded template. Utilization of ethanol precipitation in tandem with a rapid microdialysis step to purify and desalt the PCR product was crucial to obtain a precise mass measurement. The PCR product (0.8 pmol/μL) was electrosprayed from a solution containing 75% acetonitrile, 25 mM piperidine, and 25 mM imidazole and was infused at a rate of 200 nL/min. The average molecular mass and the corresponding precision were determined using the charge-states ranging from 172 to 235 net negative charges. The experimental mass and corresponding precision (reported as the 95% confidence interval of the mean) was 309 406 +/- 27 Da (87 ppm). The mass accuracy was compromised due to the fact that the PCR generates multiple products when using Taq polymerase due to the non-template directed 3'-adenylation. This results in a mixture of three PCR products with nearly identical mass (i.e. blunt-ended, mono-adenylated and di-adenylated) with unknown relative abundances that were not resolved in the spectrum. Thus, the experimental mass will be a weighted average of the three species which, under our experimental conditions, reflects a nearly equal concentration of the mono- and di-adenylated species. This report demonstrates that precise mass measurements of PCR products up to 309 kDa (500 bp) can be routinely obtained by ESI-FTICR requiring low femtomole amounts. Copyright 1999 John Wiley & Sons, Ltd. 相似文献