Two-dimensional Excitation Research Articles

Two-Dimensional Magnetic Properties of Silicon-Steel Sheet

The magnetic properties of silicon steel sheet under conditions of two-dimensional excitation (circular, elliptic and alternating the rotation direction) were investigated. "Two-dimensional magnetic measurement" is a generic term introduced recently to describe the measurement of magnetic properties of a specimen under conditions of a rotating magnetic induction. The two-dimensional magnetic properties in silicon steel sheet are very sensitive to the axis ratio and the angle of inclination of the major axis of the induction, because they are very sensitive to the anisotropy of the material.

Rapid NMR Cardiography with a Half-Echo M-Mode Method

A real-time NMR cardiac profiling pulse sequence has been developed that incorporates two-dimensional (2D) selective excitation and a half-echo readout. The time resolution has been improved by a factor of two relative to the previous flow-compensated, full-echo version. The technique produces a 2D plot of "beam"-axis position versus time, analogous to M-mode echocardiography. In human subjects, details of valve leaflet motion, intracardiac flow, wall motion, and wall thickening may be observed along optimal lines of sight selected interactively. The pulse sequence uses a low-tip-angle 2D selective-excitation pulse derived from a spiral k-space trajectory to excite a narrow cylinder of magnetization, followed by a half-echo readout gradient oriented along the axis of the cylinder. One-dimensional Fourier transformation of the acquired signal results in a magnetization profile along the length of the cylinder, or beam. The pulse sequence is effectively flow compensated without any additional gradient lobes, because the rapid oscillation in the gradient wave forms of the 2D excitation pulse produces relatively small net gradient moments, and the shortened readout gradient has minimal first-order moment relative to center echo. The signal from moving blood can alternatively be velocity encoded by the addition of bipolar gradients along any of the three axes, producing Doppler-like traces of intracardiac blood flow.

けい素鋼板の２次元磁気特性

The magnetic properties of silicon steel sheet under the condition of two-dimensional excitation (circular, elliptic and alternating with rotation of the direction) are investigated. Two-dimensional magnetic measurement is a generic term introduced recently to comprise the measurement of magnetic properties of a specimen under the condition of rotating magnetic induction. Two-magnetic properties in silicon steel sheet are very sensitive to the axis ratio and the inclination angle of the magnetic flux density of longitudinal axis,because that is very effective to the anisotropy of the sheet.

Correcting for nonuniform k-space sampling in two-dimensional NMR selective excitation

Correcting for nonuniform k-space sampling in two-dimensional NMR selective excitation

Continual NMR cardiography without gating: M-mode MR imaging.

A magnetic resonance (MR) pulse sequence was designed and implemented to examine the heart continually without gating, at rates in excess of 256 images in 7 seconds. The results are analogous to those of M-mode ultrasound, allowing interactive exploration of cardiac dynamics and flow in real time with full three-dimensional freedom of view. The technique is based on designed two-dimensional excitation pulses in which the magnetic field gradient is not constant, as in section-selection pulses, but varies in time to define a trajectory that results in a specified (eg, cylindric) region of excitation. The technique was implemented on a 1.5-T clinical imager with no special hardware and was tested on phantoms and volunteers. In human subjects, details of valve motion, intracardiac flow, and wall motion could be observed from moment to moment along optimal lines of sight selected interactively, with or without flow compensation and without gating. The momentary physiologic changes in chamber volumes and blood pool replenishment that occur during rhythm disturbances, the Valsalva maneuver, and simple breathing and breath-holding were readily demonstrated.

On the mechanism of time-dependent spectral diffusion in binary solid solutions: The 1,4-dibromonaphthalene and 1-bromo-4-chloronaphthalene system

The mechanism of the spectral diffusion process has been studied in the presence of both orientational and substitutional disorder with the help of a simple model calculation. The systems of study are different compositions of solid solutions of 1-bromo-4-chloronaphthalene and 1,4-dibromonaphthalene. The isotropic exchange mechanism for different dimensions are considered in detail. The calculation points to a two-dimensional excitation exchange interaction mechanism. Furthermore, the switching of spectral diffusion occurs at a critical effective acceptor concentration.

Recent advances in the one- and two-dimensional magnetic measurement technique for electrical sheet steel

The problems connected with measuring the magnetic properties of electrical sheet steel under the condition of one-dimensional (alternating) and two-dimensional excitation (circular, elliptic, and alternating with rotation of the direction) are surveyed. Regarding the classical case of one-dimensional excitation, the relationships between the SST (single-sheet tester) and Epstein results, and different types of SSTs and their peculiarities are considered. The main arguments in favor of the SST that determines the field strength from the magnetizing current (MC method) in comparison with that using the H procedure are greater simplicity and, therefore, greater reproducibility to be expected in practice. It is also shown that single-yoke construction is inadequate for accurate loss measurements on an electrical steel sheet. Various methods for the determination of rotational power loss are in use. The thermometric methods appear to be less effective than the more convenient and versatile field-sensing methods, which yield more information. Digital procedures are particularly useful for this kind of measurement. New magnetic circuits are under test. Standardization was deemed desirable, but a method for this purpose has not been agreed upon.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

On the receptivity of free shear layers to two-dimensional external excitation

In this paper, we study the receptivity of a typical free shear layer to pulse-type and periodic excitation. We do this by solving the initial-value problem completely and studying its long-time behaviour. This leads to a wave packet for the pulse. By the superposition of many wave packets, we generate a spatial instability mode when the flow is convectively unstable. This establishes a general and simple relationship between the receptivities for pulse-type and sinusoidal excitations. We find that a shear layer is very receptive to high-frequency disturbances that are generated near the centreline of the layer.

TURBULENT STRUCTURE AND CONTROL OF COHERENT VORTEX IN MIXING LAYER OF OPEN-CHANNEL PARALLEL COFLOWS

The effect of periodic two-dimensional excitation on the development of a turbulent mixing region in open-channel parallel coflows was investigated experimentally by making use of visual study and hot-film anemometers. Controlled oscillations of variable frequency were applied at the initiation of mixing between two parallel water flows. When the frequency of the forced oscillations was lower than the fundamental frequency (in the present case it was about 1Hz) which might describe the interaction of vortices, i. e. pairing, the spreading rate of flow was increased by enhancing the coalescence of neighbouring eddies. On the other hand, at the frequency higher than the fundamental one, the controlled and resonant vortices were generated in a single array of large vortices, which did not interact with each other. Consequently, the spreading rate of flow was depressed, and also the Reynolds stress became negative.

ChemInform Abstract: Two‐Dimensional Excitation Energy Transfer Between Chromophoric Carbazole and Anthracene in Langmuir‐Blodgett Monolayer Films.

ChemInformVolume 18, Issue 25 Physical Organic Chemistry ChemInform Abstract: Two-Dimensional Excitation Energy Transfer Between Chromophoric Carbazole and Anthracene in Langmuir-Blodgett Monolayer Films. N. TAMAI, N. TAMAI Inst. Mol. Sci., Okazaki 444, Jap.Search for more papers by this authorT. YAMAZAKI, T. YAMAZAKI Inst. Mol. Sci., Okazaki 444, Jap.Search for more papers by this authorI. YAMAZAKI, I. YAMAZAKI Inst. Mol. Sci., Okazaki 444, Jap.Search for more papers by this author N. TAMAI, N. TAMAI Inst. Mol. Sci., Okazaki 444, Jap.Search for more papers by this authorT. YAMAZAKI, T. YAMAZAKI Inst. Mol. Sci., Okazaki 444, Jap.Search for more papers by this authorI. YAMAZAKI, I. YAMAZAKI Inst. Mol. Sci., Okazaki 444, Jap.Search for more papers by this author First published: June 23, 1987 https://doi.org/10.1002/chin.198725038Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume18, Issue25June 23, 1987 RelatedInformation

Transfer-matrix method applied to multiregion cylindrical induction devices with two-dimensional current excitation

A theory is presented here to obtain the electromagnetic field in a multiregion cylindrical induction device with arbitrary two-dimensional current sheet excitation. This theory is based on the transfer-matrix method and provides a closed-form solution. It applies also to the case of one-dimensional excitation where it reduces to the known results presented by Freeman [Freeman, IEE Proc. 121, 1117 (1974); Greig and Freemen, IEE Proc. 114, 1681 (1967); Freeman and Blank, IEE Proc. 123, 149 (1976)]. A numerical example is shown, and it is in good agreement with published data.

Two-dimensional excitation energy transfer between chromophoric carbazole and anthracene in Langmuir-Blodgett monolayer films

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTwo-dimensional excitation energy transfer between chromophoric carbazole and anthracene in Langmuir-Blodgett monolayer filmsNaoto. Tamai, Tomoko. Yamazaki, and Iwao. YamazakiCite this: J. Phys. Chem. 1987, 91, 4, 841–845Publication Date (Print):February 1, 1987Publication History Published online1 May 2002Published inissue 1 February 1987https://doi.org/10.1021/j100288a017RIGHTS & PERMISSIONSArticle Views206Altmetric-Citations55LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (644 KB) Get e-Alerts

二相混合層に及ぼす外部撹乱の影響に関する可視化研究

The effect of periodic two-dimensional excitation on the development of a turbulent mixing region in open-channel parallel coflows was investigated experimentally by making use of visual study and hot-film anemometers. Controlled oscillations of variable frequency were applied at the initiation of mixing between two parallel water flows. When the frequency of the forced oscillations was lower than the fundamental frequency (in the present case it was 1 Hz) which might describe the interaction of vortices, i.e. pairing, the spreading rate of flow was increased by enhancing the coalescence of neighbouring eddies. On the other hand, at the frequency higher than the fundamental one, the controlled and resonant vortices were generated in a single array of large vortices, which did not interact with each other. Consequently, the spreading rate of flow was depressed, and also the Reynolds stress became negative.

Excitation transport and fluorescence anisotropy of Rhodamine 3B on amorphous quartz

Time-resolved fluorescence depolarization has been measured by time-correlated photon counting for submonolayers of rhodamine 3B adsorbed onto optically flat quartz. The two-dimensional excitation transport theory developed by Loring and Fayer yields fluorescence profiles which agree well with the experimental profiles for reduced surface coverages up to approx.0.4. At higher coverages, excitation trapping by rhodamine 3B aggregates truncates the depolarization process, yielding apparent reduced coverages which are appreciably lower than the true coverages. The authors present dynamic evidence that the dye transition moments are not adsorbed at a uniform angle from the macroscopic surface normal; this and other effects influencing comparisons between depolarization experiments and excitation transport theory are discussed.

Time-resolved studies of dynamics of triplet state spectral diffusion in the presence of both orientational and substitutional disorders: binary solid solutions of 1-bromo-4-chloronaphthalene and 1,4-dibromonaphthalene

The dynamics of spectral diffusion is studied in the presence of both orientational and substitutional disorders at 4.2 and 1.8 K by time-resolved and site-selective excitation methods. The systems of study are different compositions of solid solutions of 1-bromo-4-chloronaphthalene (BCN) and 1,4-dibromonaphthalene (DBN). We used a wide range of concentrations within which the DBN crystal structure prevails. The phosphorescence of BCN is monitored as a function of the excitation energy (i.e. acceptor concentration). The site-selective experiments, along with the time-resolved studies, reveal that (i) the spectral diffusion is acceptor concentration dependent; at very low acceptor concentration the excitation is completely localized; (ii) as the excitation energy is increased, the onset of spectral diffusion is observed; (iii) above a critical acceptor concentration, the spectral diffusion rate increases rapidly. A theoretical analysis based on a kinetic model suggests that the results of both the site-selective excitation and the time-resolved experiments are consistent with a two-dimensional excitation exchange interaction mechanism.

Geometric resonances of two-dimensional magnetoplasmons

Geometric resonances in the two-dimensional magnetoplasmon excitation are calculated in the framework of classical kinetic theory for arbitrary values of k nu F/ omega c and finite values of the scattering time tau (k=plasmon wavevector, nu F=Fermi velocity omega c=(e/cm) B=cyclotron frequency). The geometric resonances lead to an oscillatory behaviour of the magnetoplasmon resonance amplitude and dispersion correlated with subharmonic fields Bc/n (n=2, 3, . . .). Calculations are compared with magnetoplasmon resonance experiments in electron inversion layers of Si and the possibility of geometric resonances in single quantum well systems of GaAs-AlGaAs heterostructures is discussed.

Operator-valued transmission lines as models of a horizontally layered earth under transient two-dimensional electromagnetic excitation

A new method of computing the transient behavior of a horizontally layered earth under two-dimensional electromagnetic excitation is presented. The earth's conductivity, magnetic permeability, and electric permittivity are assumed to vary only with depth, but those variations are allowed to be quite arbitrary. Displacement current is not neglected. After discretization of Maxwell's equations, the earth is modeled by infinite RLC electrical networks. No truncations of those networks are invoked during the computational procedure. Instead, those networks are viewed as infinite ladder networks of Hilbert ports, that is, as operator-valued lumped transmission lines, and the computations are based upon the recently devised theory of such systems. This analysis yields a new surface impedance operator, which provides a considerably more comprehensive representation of the earth's behavior than does the Tikhonov-Cagniard surface impedance. For example, the Tikhonov-Cagniard surface impedance is applicable only when the electric or magnetic fields vary slowly or linearly with respect to horizontal displacements. The surface-impedance operator derived herein does not require those restrictions; only quadratic summability and Laplace transformability are needed.

Malfunction Mechanism of Induction Disk Type Relays under Earthquake Condition : Malfunction Mechanism Due to Horizontal Two-Dimensional Excitation

Malfunction Mechanism of Induction Disk Type Relays under Earthquake Condition : Malfunction Mechanism Due to Horizontal Two-Dimensional Excitation

The forced mixing layer between parallel streams

The effect of periodic two-dimensional excitation on the development of a turbulent mixing region was studied experimentally. Controlled oscillations of variable ampli- tude and frequency were applied at the initiation of mixing between two parallel air streams. The frequency of forcing was at least an order of magnitude lower than the initial instability frequency of the flow in order to test its effect far downstream. The effect of the velocity difference between the streams was also investigated in this experiment. A typical Reynolds number based on the velocity difference and the momentum thickness of the shear layer was l04.It was determined that the spreading rate of the mixing layer is sensitive to periodic surging even if the latter is so small that it does not contribute to the initial energy of the fluctuations. Oscillations at very small amplitudes tend to increase the spreading rate of the flow by enhancing the amalgamation of neighbouring eddies, but at higher amplitudes the flow resonates with the imposed oscillation. The resonance region can extend over a significant fraction of the test section depending on the Strouhal number and a dimensionless velocity-difference parameter. The flow in the resonance region consists of a single array of large, quasi-two-dimensional vortex lumps, which do not interact with one another. The exponential shape of the mean-velocity distribution is not affected in this region, but the spreading rate of the flow with increasing distance downstream is inhibited. The Reynolds stress in this region changes sign, indicating that energy is extracted from the turbulence to the mean motion; the intensity of the spanwise fluctuations is also reduced, suggesting that the flow tends to become more two-dimensional.Amalgamation of large coherent eddies is resumed beyond the resonance region, but the flow is not universally similar. There are many indications suggesting that the large eddies in the turbulent mixing layer at fairly large Re are governed by an inviscid instability.

Factors associated with support plate forces due to heat-exchanger tube vibratory contact

Abstract Studies have been made of several of the factors associated with the forces resulting from a heat-exchanger tube vibrating against its support plate. Finite element simulation results are compared with the behaviour of a cantilevered tube apparatus with two-dimensional sinusoidal excitation in air. The accuracy of the simulation technique is shown over a range of excitations. Simulations are then used to study the effects of varying the friction, damping, tube/annulus stiffness and clearance on the r.m.s. contact forces.