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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.
Alberto Damiano Daniele Struppa Adrian Vajiac Mihaela Vajiac 《Journal of Geometric Analysis》2009,19(2):288-300
We introduce the notion of antisyzygies, which studies the inverse problem of finding a system of PDEs, given compatibility
conditions. The system obtained possesses the property of removability of compact singularities. We write explicit computations
in the cases of the Cauchy-Fueter system and Maxwell’s system for electromagnetism, and we conclude with a study of systems
of non-maximal rank.
相似文献
3.
Regular polynomials with quaternionic coefficients admit only isolated zeroes and spherical zeroes. In this paper we prove
a factorization theorem for such polynomials. Specifically, we show that every regular polynomial can be written as a product
of degree one binomials and special second degree polynomials with real coefficients. The degree one binomials are determined
(but not uniquely) by the knowledge of the isolated zeroes of the original polynomial, while the second degree factors are
uniquely determined by the spherical zeroes. We also show that the number of zeroes of a polynomial, counted with their multiplicity
as defined in this paper, equals the degree of the polynomial. While some of these results are known in the general setting
of an arbitrary division ring, our proofs are based on the theory of regular functions of a quaternionic variable, and as
such they are elementary in nature and offer explicit constructions in the quaternionic setting.
Partially supported by G.N.S.A.G.A.of the I.N.D.A.M. and by M.I.U.R..
Lecture held by G. Gentili in the Seminario Matematico e Fisico on February 12, 2007.
Received: August 2008 相似文献
4.
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
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Y. Aharonov F. Colombo I. Sabadini D. C. Struppa J. Tollaksen 《Journal of Fourier Analysis and Applications》2016,22(4):751-767
In a series of papers (J Phys A 44:365304, 2011; Complex Anal Oper Theory 7:1299–1310, 2013; J Math Pures Appl 99:165–173, 2013; J Math Pures Appl 103:522–534, 2015), we have investigated some mathematical properties of superoscillating sequences in one variable, and their persistence in time. In this paper we study the notion of superoscillation in several variables and we show how to construct examples of sequences that exhibit this property. 相似文献
8.
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
9.
DC Bassett 《Macromolecular Symposia》1997,114(1):121-126
Molecular cilia, the uncrystallized portions of chains already partly attached to polymer crystals, exert a profound influence on the course of polymeric crystallization with ultimate responsibility for the divergence of adjacent lamellae which leads to spherulitic growth. Their effective size and pressure have been measured, in α-polypropylene, from electron microscopic measurements of the separation and maximum curvature of lamellae in row structures. That cilia exist and extend the effective region occupied by a lamella beyond the geometrical confines of its fold surfaces is important for crystallization theory and may well have implications for the connection of lamellae into networks and for gelation. 相似文献
10.
In this paper, we utilize techniques from the theory of nonlinear dynamical systems to define a notion of embedding estimators. More specifically, we use delay-coordinates embeddings of sets of coefficients of the measured signal (in some chosen frame) as a data mining tool to separate structures that are likely to be generated by signals belonging to some predetermined data set. We implement the embedding estimator in a windowed Fourier frame, and we apply it to speech signals heavily corrupted by white noise. Our experimental work suggests that, after training on the data sets of interest, these estimators perform well for a variety of white noise processes and noise intensity levels. 相似文献