Note: This page contains sample records for the topic level spectra electromagnetic from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: November 12, 2013.
1

Hot Electromagnetic Outflows. I. Acceleration and Spectra  

NASA Astrophysics Data System (ADS)

The theory of cold, relativistic, magnetohydrodynamic outflows is generalized by the inclusion of an intense radiation source. In some contexts, such as the breakout of a gamma-ray burst (GRB) jet from a star, the outflow is heated to a high temperature at a large optical depth. Eventually it becomes transparent and is pushed to a higher Lorentz factor by a combination of the Lorentz force and radiation pressure. We obtain its profile, both inside and outside the fast magnetosonic critical point, when the poloidal magnetic field is radial and monopolar. Most of the energy flux is carried by the radiation field and the toroidal magnetic field that is wound up close to the rapidly rotating engine. Although the entrained matter carries little energy, it couples the radiation field to the magnetic field. Then the fast critical point is pulled inward from infinity and, above a critical radiation intensity, the outflow is accelerated mainly by radiation pressure. We identify a distinct observational signature of this hybrid outflow: a hardening of the radiation spectrum above the peak of the seed photon distribution, driven by bulk Compton scattering. The non-thermal spectrum—obtained by a Monte Carlo method—is most extended when the Lorentz force dominates the acceleration, and the seed photon beam is wider than the Lorentz cone of the MHD fluid. This effect is a generic feature of hot, magnetized outflows interacting with slower relativistic material. It may explain why some GRB spectra appear to peak at photon energies above the original Amati et al. scaling. A companion paper addresses the case of jet breakout, where diverging magnetic flux surfaces yield strong MHD acceleration over a wider range of Lorentz factor.

Russo, Matthew; Thompson, Christopher

2013-04-01

2

Electromagnetically induced transparency, electromagnetically induced absorption, and giant Kerr effect in closed degenerate two-level systems  

NASA Astrophysics Data System (ADS)

Spontaneous transfer of coherence has proven to be a good interpretative scheme for the explantation of the spectra of a probe laser probing a closed degenerate two-level systems. With its aid it was possible to give an explanation for the emergence of electromagnetically induced absorption and also to make predictions on the associated coupling laser spectra. Here we extend our work on the role of the coupling laser in electromagnetically induced absorption presenting new measurements of the probe and coupling laser absorption and dispersion spectra - taken in the D2 line of caesium - which reassert the importance of spontaneous transfer of coherence in the generation of electromagnetically induced absorption spectra. All measurements were performed with linearly polarised coupling and probe laser of orthogonal polarisation, acting on a perpendicularly propagating caesium atomic beam to minimise the Doppler broadening of the lines. For sake of completeness we compared the electromagnetically induced absorption spectra with electromagnetically induced transparency spectra obtained in another two-level system within the same line. The measured probe spectra were used to calculate the refractive index of caesium in the presence of electromagnetically induced transparency and absorption. On that basis we could calculate the effect of Kerr nonlinearities and measure nonlinear Kerr coefficients of the order of n2 ~ 10-5 cm2/mW with absorption coefficients of the order of ? ~ 0.1 cm-1.

Spani Molella, Luca; Rinkleff, Rolf-Hermann; Kühn, Gerrit; Danzmann, Karsten

2007-03-01

3

Polarized linewidth-controllable double-trapping electromagnetically induced transparency spectra in a resonant plasmon nanocavity  

NASA Astrophysics Data System (ADS)

Surface plasmons with ultrasmall optical mode volume and strong near field enhancement can be used to realize nanoscale light-matter interaction. Combining surface plasmons with the quantum system provides the possibility of nanoscale realization of important quantum optical phenomena, including the electromagnetically induced transparency (EIT), which has many applications in nonlinear quantum optics and quantum information processing. Here, using a custom-designed resonant plasmon nanocavity, we demonstrate polarized position-dependent linewidth-controllable EIT spectra at the nanoscale. We analytically obtain the double coherent population trapping conditions in a double-? quantum system with crossing damping, which give two transparent points in the EIT spectra. The linewidths of the three peaks are extremely sensitive to the level spacing of the excited states, the Rabi frequencies and detunings of pump fields, and the Purcell factors. In particular the linewidth of the central peak is exceptionally narrow. The hybrid system may have potential applications in ultra-compact plasmon-quantum devices.

Wang, Luojia; Gu, Ying; Chen, Hongyi; Zhang, Jia-Yu; Cui, Yiping; Gerardot, Brian D.; Gong, Qihuang

2013-10-01

4

Polarized linewidth-controllable double-trapping electromagnetically induced transparency spectra in a resonant plasmon nanocavity  

PubMed Central

Surface plasmons with ultrasmall optical mode volume and strong near field enhancement can be used to realize nanoscale light-matter interaction. Combining surface plasmons with the quantum system provides the possibility of nanoscale realization of important quantum optical phenomena, including the electromagnetically induced transparency (EIT), which has many applications in nonlinear quantum optics and quantum information processing. Here, using a custom-designed resonant plasmon nanocavity, we demonstrate polarized position-dependent linewidth-controllable EIT spectra at the nanoscale. We analytically obtain the double coherent population trapping conditions in a double-? quantum system with crossing damping, which give two transparent points in the EIT spectra. The linewidths of the three peaks are extremely sensitive to the level spacing of the excited states, the Rabi frequencies and detunings of pump fields, and the Purcell factors. In particular the linewidth of the central peak is exceptionally narrow. The hybrid system may have potential applications in ultra-compact plasmon-quantum devices.

Wang, Luojia; Gu, Ying; Chen, Hongyi; Zhang, Jia-Yu; Cui, Yiping; Gerardot, Brian D.; Gong, Qihuang

2013-01-01

5

Polarized linewidth-controllable double-trapping electromagnetically induced transparency spectra in a resonant plasmon nanocavity.  

PubMed

Surface plasmons with ultrasmall optical mode volume and strong near field enhancement can be used to realize nanoscale light-matter interaction. Combining surface plasmons with the quantum system provides the possibility of nanoscale realization of important quantum optical phenomena, including the electromagnetically induced transparency (EIT), which has many applications in nonlinear quantum optics and quantum information processing. Here, using a custom-designed resonant plasmon nanocavity, we demonstrate polarized position-dependent linewidth-controllable EIT spectra at the nanoscale. We analytically obtain the double coherent population trapping conditions in a double-? quantum system with crossing damping, which give two transparent points in the EIT spectra. The linewidths of the three peaks are extremely sensitive to the level spacing of the excited states, the Rabi frequencies and detunings of pump fields, and the Purcell factors. In particular the linewidth of the central peak is exceptionally narrow. The hybrid system may have potential applications in ultra-compact plasmon-quantum devices. PMID:24096943

Wang, Luojia; Gu, Ying; Chen, Hongyi; Zhang, Jia-Yu; Cui, Yiping; Gerardot, Brian D; Gong, Qihuang

2013-10-07

6

Catalog of Dynamic Electromagnetic Spectra Observed with Callisto and Phoenix - 3: Part 2  

NASA Astrophysics Data System (ADS)

This second part of the catalog demonstrates dynamic electromagnetic spectra observed by Callisto radio spectrometers. In the first (previous) part we presented natural spectra while in this second part we concentrate on artificial (man-made) spectra. This catalog has been prepared to help the amateur detect and identify weak solar radio flares in highly interfered conditions. In addition to their role in the e-Callisto solar radio spectrometer network, Callisto spectrometers have proven to be a cheap and reliable instrument for radio frequency monitoring of terrestrial radio interference. Information on e-Callisto may be found at http://www.e-callisto.org/.

Monstein, C.

2013-02-01

7

3D electromagnetic modeling and design flow in system level  

Microsoft Academic Search

In this paper the aspects of system level modeling are discussed. We present a possible procedure that treats numerical modeling and measurement procedure as a similar process. Another topic in this paper is geometric model used as an input for electromagnetic (EM) analysis. We have shown implementation of geometric models for electromagnetic analysis in a design frame, and how separate

Antti Renko; A. N. Arslan; Sergey Yuferev; M. Uusimaki

2003-01-01

8

Catalogue of Dynamic Electromagnetic Spectra Observed with Callisto and Phoenix - 3  

NASA Astrophysics Data System (ADS)

This catalog demonstrates dynamic electromagnetic spectra observed by Callisto radio spectrometers. In this first part natural spectra are presented while in the second part in the next SARA journal we concentrate on artificial (man-made) spectra. This catalog shall help the amateur to detect and identify weak flares in highly interfered spectra. In addition to their role in the e-Callisto solar radio spectrometer network, Callisto spectrometers have proven to be a cheap and reliable instrument for radio frequency monitoring of terrestrial interference. Information on e-Callisto may be found at http://www.e-callisto.org/. Technical information on Phoenix-3 Fast Fourier Transform spectrometer may be found at http://soleil.i4ds.ch/solarradio/data/Description/phoenix3.pdf

Monstein, Christian

2012-12-01

9

Estimation of vertical sea level muon energy spectra from the latest primary cosmic ray elemental spectra  

Microsoft Academic Search

The directly measured elemental spectra of primary cosmic rays obtained from Webber et al., Seo et al., Menn et al., Ryan et al. and experiments like JACEE, CRN, SOKOL, RICH on P, He, CNO, Ne-S and Fe have been considered to estimate the vertical sea level muon energy spectra. The primary elemental energy spectra of P, He, CNO, Ne-S and

M. Mitra; N. H. Molla; D. P. Bhattacharyya

2001-01-01

10

Spectra and electromagnetic transitions of 98–104Zr in the interacting boson model  

NASA Astrophysics Data System (ADS)

The low-lying energy levels and electromagnetic transitions of even-even nuclei 98Zr, 100Zr, 102Zr, 104Zr are studied within the framework of the interacting boson model. The Hamiltonian matrix elements and some of their states have been respectively analyzed and determined with respect to the current nuclear experimental data. The B(E2) of electromagnetic transitions have also been calculated and the wave function structures also analyzed. The results show good agreement with the available experimental data. The present study shows that these series of nuclei are in the transition from U(5) to SU(3), namely from vibration to rotation.

Dong, Hong-Fei; Cao, Wan-Cang; Zhang, Hao-Ran

2013-07-01

11

Vibrational spectra of free and intracellular DNA in the weak electromagnetic field  

NASA Astrophysics Data System (ADS)

Vibrational bands of DNA molecules from birds' erythrocytes, as well as Dunaliella viridis alga cells and Escherichia coli bacteria clinical strains in the weak microwave field were investigated with IR spectroscopy. Drastic changes were detected in the intensities and fine structure of C equals O and PL2 bands for polarized spectra of irradiated samples of DNA molecules as compared with the reference samples in the 1700-1000 cm-1 region. No essential changes were detected in the IR spectra in the region of PO2 bands of DNA for the Escherichia coli, irradiated by the weak electromagnetic field, but essential redistribution of intensities and change in halfwidths of the PO2 symmetrical bonds were detected for Dunaliella viridis alga cells.

Dovbeshko, Galina I.

1998-09-01

12

Electromagnetically induced blazed grating at low light levels  

NASA Astrophysics Data System (ADS)

We propose a scheme for inducing a blazed transmission grating in a four-level, N-type atomic medium under electromagnetically induced transparency (EIT). The blazed grating relies on the giant Kerr nonlinearity that the atomic medium exhibits under EIT. The grating is created using an intensity mask in one of the driving optical fields and only weak fields with intensities below saturation level are involved. Diffraction efficiencies of a resonant probe beam close to 100% are predicted.

Carvalho, Silvânia A.; de Araujo, Luís E. E.

2011-05-01

13

Utilizing electromagnetic-acoustic resonators for liquid level sensing  

Microsoft Academic Search

Electromagnetic excitation of acoustic resonators sensors as an alternative to piezoelectric and capacitive acoustic sensors provides unique benefits of remote, multi-mode measurements. Utilizing out-of-plane modes of vibration, we have employed the devices as liquid level sensors. The resolution is not limited by the wavelength (as for time-of-flight ultrasonic sensors), since small frequency changes due to interference effects of the generated

Frieder Lucklum; Bernhard Jakoby

2009-01-01

14

3D Statistical Parametric Mapping of EEG Source Spectra by Means of Variable Resolution Electromagnetic Tomography (VARETA)  

Microsoft Academic Search

This article describes a new method for 3D QEEG tomography in the frequency domain. A variant of Statistical Parametric Mapping is presented for source log spectra. Sources are estimated by means of a Discrete Spline EEG inverse solution known as Variable Resolution Electromagnetic Tomography (VARETA). Anatomical constraints are incorporated by the use of the Montreal Neurological Institute (MNI) probabilistic brain

J. Bosch-Bayard; P. Valdés-Sosa; T. Virues-Alba; E. Aubert-Vázquez; E. Roy John; Thalia Harmony; J. Riera-Díaz; N. Trujillo-Barreto

2001-01-01

15

Exact Spin Coherent State Path Integral for a Damped Two-Level Atom in an Electromagnetic Wave  

NASA Astrophysics Data System (ADS)

The spin coherent state path integral describing the dynamics of a two-level system interacting with electromagnetic wave of circular polarization is considered. The propagator is first written in the standard form by replacing the spin by a unit vector aligned along the polar and azimuthal directions. Then it is determined exactly using a simple transformations. Thus, the exact energy spectra with corresponding wave functions are deduced.

Halimi, Farida; Aouachria, Mekki

2013-10-01

16

Patterns of energy levels and spectra for polyatomic molecules  

SciTech Connect

Laser spectroscopy has revealed a remarkable intricacy in the rotational, vibrational, and electronic energy levels for polyatomic molecules. The infrared spectra of SF/sub 6/, CF/sub 4/, and related molecules contain several levels of structure on top of structure which resembles a fractal in some ways. The purpose of this article will be to exhibit some of this structure and introduce the simplest theoretical interpretations of it which are presently available.

Harter, W.G.

1983-01-01

17

Estimation of vertical sea level muon energy spectra from the latest primary cosmic ray elemental spectra  

NASA Astrophysics Data System (ADS)

The directly measured elemental spectra of primary cosmic rays obtained from Webber et al., Seo et al., Menn et al., Ryan et al. and experiments like JACEE, CRN, SOKOL, RICH on P, He, CNO, Ne-S and Fe have been considered to estimate the vertical sea level muon energy spectra. The primary elemental energy spectra of P, He, CNO, Ne-S and Fe available from the different experimental data duly fitted by power law are given by Np(E)dE = 1.2216E-2.68 dE [cm2 .s.sr.GeV/n]-1 NHe(E)dE = 0.0424E-2.59 dE [cm2 .s.sr.GeV/n]-1 NCNO(E)dE = 0.0026E-2.57 dE[cm2 .s.sr.GeV/n]-1 NNe-S(E)dE = 0.00066E-2.57 dE [cm2 .s.sr.GeV/n]-1 NF e(E)dE = 0.0056E-2.55 dE [cm2 .s.sr.GeV/n]-1 Using the conventional superposition model the all nucleon primary cosmic ray spectrum has been derived which is of the form N(E)dE = 1.42E-2.66 dE [cm2 .s.sr.GeV/n]-1 We have considered all these spectra separately as parents of the secondary mesons and finallty the sea level muon fluxes at 00 from each species have been derived. To evaluate the meson spectra which are the initial air shower interaction products initiated by the primary nucleon air collisions, the hadronic energy moments have been calculated from the CERN LEBCEHS data for pp collisions and FNAL data for ?p collisions. Pion production by secondary pions have been taken into account and the final total muon spectrum has been derived from pp rightarrow?± x, pp ? K± x, ?p ? ?± x channels. The Z-factors have been corrected for p-air collisions. We have adopted the constant values of ?p-air and ??-air crosssections which are 273 mb and 213 mb, respectively. The adopted inelastic cross-sections for pp and ?p interactions are 35 mb and 22 mb, respectively. The Q-G plasma correction of Z-factors have also been incorporated in the final form. The solution to the standard differential equation for mesons is considered for muon flux estimation from Ngenerations of the parent mesons. By this formulation vertical muon spectra from each element along with the total primary nucleon spectrum have been derived. We wanted to observe the different shape of the muon spectra evaluated from different elemental spectra and to make a comparative study of that. In this energy range (102 - 104 ) GeV we have observed that the majority of the total muon flux is coming from the proton spectra. The contribution from the other elemental spectra to the total muon flux is not at all comparable with that of proton spectra.

Mitra, M.; Molla, N. H.; Bhattacharyya, D. P.

18

Tunneling spectra for electrons in the lowest Landau level  

NASA Astrophysics Data System (ADS)

The recently developed experimental technique of time dependent capacitance spectroscopy [1] allows for measurements of high-resolution tunneling spectra of 2DEGs in the quantum Hall regime, giving a detailed probe of the single particle spectral function (electron addition and subtraction spectra). These experiments show a number of interesting features including Landau level structure, exchange enhanced Zeeman energy, Coulomb gap physics, effects of fractional quantization, as well as several key features that remain to be explained. While there has been some prior theoretical work[2] towards explaining low energy Coulomb gap features of tunneling spectra found in much earlier tunneling experiments [3], the new experiments[1] have uncovered physics outside of the prior theoretical explanations. Building on a number of these prior theoretical works, we investigate theoretically the expected tunneling spectra for electrons in low Landau levels, including the effects of electron spin and coupling to collective modes. [1] O. E. Dial, R.C. Ashoori, L.N. Pfeiffer, and K.W. West, Nature 448, 176-179 (2007) ; O. E. Dial et al, unpublished. [2] I. Aleiner et al, Phys. Rev. Lett 74 3435; (1994) S. R. E. Yang and A. MacDonald PRL 70 4110 (1993); S. He, P.M. Platzman, and B. I. Halperin, PRL 71 777 (1993). [3] J. P. Eisenstein et al, Phy. Rev. Lett. 69, 3804 (1992).

Burnell, F. J.; Simon, Steven H.

2010-03-01

19

Electromagnets  

NSDL National Science Digital Library

In this investigation, students will construct electromagnets and test to see which variables make them stronger. Although elementary and middle school teachers are expected to have done this activity with their classes, teachers of younger students often

Horton, Michael

2009-05-30

20

Temporal buildup of electromagnetically induced transparency and absorption resonances in degenerate two-level transitions  

SciTech Connect

The temporal evolution of electromagnetically induced transparency (EIT) and absorption (EIA) coherence resonances in pump-probe spectroscopy of degenerate two-level atomic transition is studied for light intensities below saturation. Analytical expressions for the transient absorption spectra are given for simple model systems and a model for the calculation of the time-dependent response of realistic atomic transitions, where the Zeeman degeneracy is fully accounted for, is presented. EIT and EIA resonances have a similar (opposite sign) time-dependent line shape, however, the EIA evolution is slower and thus narrower lines are observed for long interaction time. Qualitative agreement with the theoretical predictions is obtained for the transient probe absorption on the {sup 85}Rb D{sub 2} line in an atomic beam experiment.

Valente, P.; Failache, H.; Lezama, A. [Instituto de Fisica, Facultad de Ingenieria, Casilla de correo 30, 11000 Montevideo (Uruguay)

2003-01-01

21

GRABGAM Analysis of Ultra-Low-Level HPGe Gamma Spectra  

SciTech Connect

The GRABGAM code has been used successfully for ultra-low level HPGe gamma spectrometry analysis since its development in 1985 at Savannah River Technology Center (SRTC). Although numerous gamma analysis codes existed at that time, reviews of institutional and commercial codes indicated that none addressed all features that were desired by SRTC. Furthermore, it was recognized that development of an in-house code would better facilitate future evolution of the code to address SRTC needs based on experience with low-level spectra. GRABGAM derives its name from Gamma Ray Analysis BASIC Generated At MCA/PC.

Winn, W.G.

1999-07-28

22

Invariance and noninvariance of the spectra of stochastic electromagnetic beams on propogation  

NASA Astrophysics Data System (ADS)

It has been known for some time that the spectrum of light may change on propagation, even in free space. The theory of this phenomenon was developed within the framework of scalar theory. We generalize it to electromagnetic beams, generated by planar, secondary, stochastic sources. We also derive an electromagnetic analog of the so-called scaling law. When this law is satisfied the normalized spectrum of the beam is the same throughout the far zone and across the source.

Pu, Jixiong; Korotkova, Olga; Wolf, Emil

2006-07-01

23

The Permittivity and Permeability of Solid, Granular, Electromagnetic Materials: a Critical Examination and Extension of Current Method for Spectra Calculation  

NASA Astrophysics Data System (ADS)

This work examines and extends the present analytic technique for calculating the permeability and permittivity spectra of composite materials. It addresses the relationship between grain properties and their sizes and the permeability and permittivity spectra of polycrystalline material. The work begins by considering the interior and exterior fields about a sphere of arbitrary permittivity and permeability illuminated by an incident electromagnetic plane wave, over a frequency range where the product of the wavevector 'k' and sphere radius 'a' is always small. The fields are found using two methods: the standard multipolar method and Stevenson's method. An in-depth comparison between the two methods is made. Stevenson's method can only be used when the product of the internal wave vector k _{rm i} and sphere radius, equal to ka(muvarepsilon) ^{1/2}, is small, however the multipolar method has no such constraint. The scattered multipolar fields about a single sphere are related to the polarizability of an ordered congregation of such spheres. Using the Clausius-Mossotti relation the effective permeability and permittivity spectra of a congregate polycrystalline material is determined for arbitrary size, permittivity, and permeability of the individual, identical spheres making up the composite. Although we consider the spectra over a range where the product ka is kept small, typically less than one-tenth, the product k_{rm i}a can be quite large. The theory developed predicts many different spectra types; including complex permittivity and permeability spectra that have been measured experimentally and explained by either including multiple sources or statistical weighing. The theory presented here predicts both the 'classical' and 'anomolous' spectra that have been experimentally measured, without employing multiple additive sources. It also predicts the more difficult, conglomerate spectra that have been measured for which no theory has been put forth to explain. Results presented here suggest that the permeability and permittivity spectra of composite materials, considered as an ordered array of uniform spheres, can be simply explained as the manifestations of electromagnetic boundary conditions and dimensional effects of the size to wavelength ratio.

Grimes, Craig Alan

24

Electromagnets  

NSDL National Science Digital Library

In this activity, the students will complete the grand challenge and design an electromagnet to separate steel from aluminum for the recycler. In order to do this, students compare the induced magnetic field of an electric current with the magnetic field of a permanent magnet and must make the former look like the latter. They discover that looping the current produces the desired effect and find ways to further strengthen the magnetic field.

Vu Bioengineering Ret Program

25

A PORTABLE MEASUREMENT SYSTEM BASED ON A PDA DEVICE FOR ACQUIRING AND TESTING ELECTROMAGNETIC FIELD LEVELS  

Microsoft Academic Search

In this paper an user-friendly and manageable measurement system for environmental monitoring and control applications is presented. The specific experimental case concerns the acquisition and processing of the exposure levels to environmental electromagnetic field (EMF). The proposed measurement instrument is equipped with a Personal Digital Assistant (PDA) device and a field probe sensing the electromagnetic field in high frequency range.

C. De Capua; A. Liccardo; R. Morello

26

Utilization of Target Scattering to Measure High-Level Electromagnetic Fields: The MICHELSON Method  

Microsoft Academic Search

The intention of this paper is to present the instantaneous electromagnetic field measurement by signature of a neutral object (MICHELSON) method. The MICHELSON method is relatively new and enables the measurement of high-level electromagnetic fields from the utilization of a target. The incident field scattering on the target allows us to move the field measurement to a new location where

Stephane Vauchamp; Michèle Lalande; Joël Andrieu; Bernard Jecko; Jean Louis Lasserre; Laurent Pecastaing; Baptiste Cadilhon

2010-01-01

27

Hydrodynamical description of 200{bold {ital A}} GeV/{ital c} S+Au collisions: Hadron and electromagnetic spectra  

SciTech Connect

We study relativistic S+Au collisions at 200A GeV/c using a hydrodynamical approach. We test various equations of state (EOS{close_quote}s), which are used to describe the strongly interacting matter at densities attainable in the CERN-SPS heavy ion experiments. For each EOS, suitable initial conditions can be determined to reproduce the experimental hadron spectra; this emphasizes the ambiguity between the initial conditions and the EOS in such an approach. Simultaneously, we calculate the resulting thermal photon and dielectron spectra, and compare with experiments. If one allows the excitation of resonance states with increasing temperature, the electromagnetic signals from scenarios with and without phase transition are very similar and are not resolvable within the current experimental resolution. Only EOS{close_quote}s with a few degrees of freedom up to very high temperatures can be ruled out presently. We deduce an upper bound of about 250 MeV for the initial temperature from the single photon spectra of WA80. With regard to the CERES dilepton data, none of the EOS{close_quote}s considered, in conjunction with the standard leading order dilepton rates, succeed in reproducing the observed excess of dileptons below the {rho} peak. Our work, however, suggests that an improved measurement of the photon and dilepton spectra has the potential to strongly constrain the EOS. {copyright} {ital 1997} {ital The American Physical Society}

Sollfrank, J. [Research Institute for Theoretical Physics, University of Helsinki (Finland); Huovinen, P.; Kataja, M.; Ruuskanen, P.V. [Department of Physics, University of Jyvaeskylae (Finland); Prakash, M. [Physics Department, SUNY at Stony Brook, Stony Brook, New York 11794 (United States); Venugopalan, R. [National Institute for Nuclear Theory, University of Washington, Seattle, Washington 98195 (United States)

1997-01-01

28

Level density from evaporation spectra for proton rich nuclei  

NASA Astrophysics Data System (ADS)

The level density is an important characteristic of atomic nuclei. It tells us about the nuclear structure and is needed to calculate reaction rates. The experimental information about the level density and corresponding model parameter systematics are available for the nuclei close to the stability line but little is known for the nuclei beyond the stability line. It follows from theoretical consideration that several physical effects might give the of Fermi-gas parameter `a' dependence on N and/or Z rather than on simply on A [1]. To study this and other features, the level density from neutron evaporation spectra has been measured for proton-rich nuclei ^60Zn and ^56Ni as well as for corresponding stable nuclei ^60Ni and^ 56Fe of the same A. Targets of ^58Ni, ^54Fe,^ 58Fe, and ^55Mn were bombarded with beams of 3He and deuterium at Ohio University's Edwards Accelerator Laboratory. Neutron energies were determined by the time-of-flight method. The different level density models have been tested in the excitation energy interval up to 8-10 MeV and the best parameters have been found. The results are compared to available systematics as well as to calculations performed on the basis of microscopic model recommended in RIPL data base. [1] S.I. Al-Quraishi, S.M.Grimes, T.N. Massey and D.A.Resler, Phys.Rev. C63, 065803 (2001).

Voinov, Alexander

2005-04-01

29

Phenomenology of inclusive fast-nucleon spectra in weak, electromagnetic, and strong nuclear processes  

SciTech Connect

The spectrum of fast backward nucleons emitted in nucleon-nucleus scattering is correlated with the inclusive fast-neutron spectra from ..mu.. capture and radiative ..pi.. capture by using a universal, phenomenological nuclear recoil function. Agreement with experiment, where available, is good.

Singer, P.; Mukhopadhyay, N.C.; Amado, R.D.

1979-01-15

30

Spectra and energy levels of trivalent samarium in strontium fluorapatite  

Microsoft Academic Search

Absorption and fluorescence spectra are reported for Sm3+(4f5) as a dopant in crystals of strontium fluorapatite, Sr5(PO4)3F. Spectra were obtained at sample temperatures near 10, 100 K, and room temperature. The absorption spectra covered the wavelength range between 2840 and 520 nm and were analyzed for the detailed crystal-field splitting of the 6HJ,6FJ,4G(4)5\\/2, and 4F(3)3\\/2 multiplet manifolds of Sm3+(4f5). Fluorescence

John B. Gruber; Bahram Zandi; Michael Ferry; Larry D. Merkle

1999-01-01

31

Spectra and energy levels of trivalent samarium in strontium fluorapatite  

Microsoft Academic Search

Absorption and fluorescence spectra are reported for Sm3+(4f5) as a dopant in crystals of strontium fluorapatite, Sr5(PO4)3F. Spectra were obtained at sample temperatures near 10, 100 K, and room temperature. The absorption spectra covered the wavelength range between 2840 and 520 nm and were analyzed for the detailed crystal-field splitting of the 6HJ, 6FJ, 4G(4)5\\/2, and 4F(3)3\\/2 multiplet manifolds of

John B. Gruber; Bahram Zandi; Michael Ferry; Larry D. Merkle

1999-01-01

32

Electromagnetically induced transparency in a five-level {Lambda} system dominated by two-photon resonant transitions  

SciTech Connect

We study the steady optical response of a five-level atomic system in the parametric region where resonant two-photon transitions are much stronger than far-detuned single-photon transitions. We find that the concurrent absorption of two weak probe fields can be well suppressed in a narrow spectral region to attain electromagnetically induced transparency (EIT) via quantum destructive interference between different two-photon transition pathways. To gain a deeper insight into relevant physics, we adiabatically reduce this five-level system with trivial single-photon transitions into a three-level system with vanishing single-photon transitions by deriving an effective Hamiltonian. The two systems have almost the same two-photon absorption spectra exhibiting typical EIT features but are a little different in fine details. This means that most characteristics of two-photon quantum destructive interference are reserved after the adiabatic elimination approximation. In addition, we verify by numerical calculations that the two-photon EIT spectra are insensitive to the dipole-dipole interaction of cold Rydberg atoms when the uppermost level has a high principle quantum number.

Yan Dong [College of Physics, Jilin University, Changchun 130012 (China); School of Science, Changchun University, Changchun 130022 (China); Gao Jinwei; Bao Qianqian; Yang Hong; Wang Heng; Wu Jinhui [College of Physics, Jilin University, Changchun 130012 (China)

2011-03-15

33

Decay of a weakly bound level in a monochromatic electromagnetic field and a static magnetic field  

SciTech Connect

We consider an electron that is bound by a zero-range potential and a constant magnetic field and which becomes disturbed by a monochromatic laser beam with elliptical polarization. The exact solution of the Schroedinger equation for an electron in the presence of an arbitrary electromagnetic wave and a static magnetic field is obtained. Exact expressions have been found for the complex energy, whose real and imaginary parts yield the level position and the width of an electron in a zero-range force field, a constant magnetic field, and a monochromatic electromagnetic field. These expressions have been analyzed in details for the case of a circularly polarized laser light.

Rylyuk, V.M. [Department of Theoretical Physics, University of Odessa, Dvorjanskaja 2, 270100 Odessa (Ukraine); Ortner, J. [Institut fuer Physik, Humboldt Universitaet zu Berlin, Invalidenstrasse 110, 10115 Berlin (Germany)

2003-01-01

34

Matter coupling to strong electromagnetic fields in two-level quantum systems with broken inversion symmetry.  

PubMed

We demonstrate theoretically the parametric oscillator behavior of a two-level quantum system with broken inversion symmetry exposed to a strong electromagnetic field. A multitude of resonance frequencies and additional harmonics in the scattered light spectrum as well as an altered Rabi frequency are predicted to be inherent to such systems. In particular, dipole radiation at the Rabi frequency appears to be possible. Since the Rabi frequency is controlled by the strength of the coupling electromagnetic field, the effect can serve for the frequency-tuned parametric amplification and generation of electromagnetic waves. Manifestation of the effect is discussed for III-nitride quantum dots with strong built-in electric field breaking the inversion symmetry. Terahertz emission from arrays of such quantum dots is shown to be experimentally observable. PMID:19257272

Kibis, O V; Slepyan, G Ya; Maksimenko, S A; Hoffmann, A

2009-01-12

35

Nuclear energy levels: applications to complex 57Fe mossbauer spectra  

Microsoft Academic Search

Explicit expressions are derived for the energy levels of a nucleus in the presence of a strong magnetic field and a small quadrupole interaction. The case of a spin 3\\/2 nucleus is considered in some detail and certain inequalities between the various zeeman energy level spacings are derived. These inequalities are used to show that computer programs which adjust the

S. K. Arif; D. St. P. Bunbury; G. J. Bowden; R. K. Day

1975-01-01

36

The propagation and interaction dynamics of electromagnetic field clusters in two-level media  

Microsoft Academic Search

An analysis is made of the propagation and interaction dynamics of electromagnetic field clusters in nonlinear media when the current generation effect can be described within the framework of the two-level quantum system (the Maxwell-Bloch equations). For the case of an absorbing two-level medium, the collision properties of the steady halfwave solution are analyzed. The notion of the 'population inversion'

E. M. Belenov; A. V. Nazarkin; V. A. Ushchapovskii

1991-01-01

37

Electromagnetically-induced-transparency-based cross-phase-modulation at attojoule levels  

SciTech Connect

We report the experimental demonstration of electromagnetically-induced-transparency-based cross-phase-modulation at attojoule or, equivalently, few-hundred-photon levels. A phase shift of 0.005 rad of a probe pulse modulated by a signal pulse with an energy of {approx}100 aJ, equivalent to {approx}400 photons, was observed in a four-level system of cold {sup 87}Rb atoms.

Lo, Hsiang-Yu; Chen, Yen-Chun; Su, Po-Ching; Chen, Hao-Chung; Chen, Jun-Xian; Chen, Yong-Fan [Department of Physics, National Cheng Kung University, Tainan 701, Taiwan (China); Chen, Ying-Cheng [Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan (China); Yu, Ite A. [Department of Physics, National Tsing Hua University, Hsinchu 300, Taiwan (China)

2011-04-15

38

Geomagnetic Cutoff Effect on Atmospheric Muon Spectra at Ground Level  

Microsoft Academic Search

We observed ground level atmospheric muon fluxes at Ft. Sumner, New Mexico in September 2001. We have obtained an absolute flux and a charge ratio of muon in a momentum range from 0.6 to 10 GeV\\/c . In this report, we compare the observed results of the flux and charge dependence with those previous measured at different locations, and discuss

K. Tanizaki; K. Abe; T. Sanuki; K. Anraku; H. Fuke; S. Haino; N. Ikeda; A. Itasaki; K. Izumi; T. Maeno; Y. Makida; S. Matsuda; N. Matsui; M. Motoki; J. Nishimura; M. Nozaki; H. Omiya; S. Orito; M. Sasaki; Y. Shikaze; J. Suzuki; K. Tanaka; T. Yamagami; A. Yamamoto; Y. Yamamoto; K. Yamato; T. Yoshida; K. Yoshimura

2003-01-01

39

Estimating the Level of Motion Sickness Based on EEG Spectra  

Microsoft Academic Search

\\u000a Motion sickness (MS) is a normal response to real, perceived, or even anticipated movement. People tend to get motion sickness\\u000a on a moving boat, train, airplane, car, or amusement park rides. Although many motion sickness-related biomarkers have been\\u000a identified, but how to estimate human’s motion sickness level (MSL) is a big challenge in the operational environment. Traditionally,\\u000a questionnaire and physical

Li-Wei Ko; Chun-Shu Wei; Tzyy-Ping Jung; Chin-Teng Lin

40

Similarities in the screening effects of the core level and valence band spectra of VO2.  

PubMed

We calculated the core level and valence band spectra of VO(2) using an extended cluster model. The distribution of spectral weight is similar in both core level and valence band spectra and is related to the different screening mechanisms. Namely, the low energy structures in the spectra correspond to well screened final states, whereas the poorly screened final states appear at higher energies. The latter produce the charge transfer satellite observed in the core level spectra, and are related to the resonance in the constant initial state spectra of the valence band. The changes in the spectral weight across the metal-insulator transition are due to the different non-local screening channels present in each phase, and are also similar in both core level and valence band spectra. The calculation also shows a relatively large O 2p contribution in both spectra, which, in turn, helps to explain the enhancement of the coherent feature at higher photon energies. This suggests that the incoherent peak cannot be solely attributed to the lower Hubbard band. PMID:21403203

Mossanek, R J O; Abbate, M

2010-08-25

41

A micro electromagnetic low level vibration energy harvester based on MEMS technology  

Microsoft Academic Search

This paper presents a micro electromagnetic energy harvester which can convert low level vibration energy to electrical power.\\u000a It mainly consists of an electroplated copper planar spring, a permanent magnet and a copper planar coil with high aspect\\u000a ratio. Mechanical simulation shows that the natural frequency of the magnet-spring system is 94.5 Hz. The resonant vibration\\u000a amplitude of the magnet is

Peihong Wang; Katsuhiko Tanaka; Susumu Sugiyama; Xuhan Dai; Xiaolin Zhao; Jingquan Liu

2009-01-01

42

Treatment of advanced hepatocellular carcinoma with very low levels of amplitude-modulated electromagnetic fields  

PubMed Central

Background: Therapeutic options for patients with advanced hepatocellular carcinoma (HCC) are limited. There is emerging evidence that the growth of cancer cells may be altered by very low levels of electromagnetic fields modulated at specific frequencies. Methods: A single-group, open-label, phase I/II study was performed to assess the safety and effectiveness of the intrabuccal administration of very low levels of electromagnetic fields amplitude modulated at HCC-specific frequencies in 41 patients with advanced HCC and limited therapeutic options. Three-daily 60-min outpatient treatments were administered until disease progression or death. Imaging studies were performed every 8 weeks. The primary efficacy end point was progression-free survival ?6 months. Secondary efficacy end points were progression-free survival and overall survival. Results: Treatment was well tolerated and there were no NCI grade 2, 3 or 4 toxicities. In all, 14 patients (34.1%) had stable disease for more than 6 months. Median progression-free survival was 4.4 months (95% CI 2.1–5.3) and median overall survival was 6.7 months (95% CI 3.0–10.2). There were three partial and one near complete responses. Conclusion: Treatment with intrabuccally administered amplitude-modulated electromagnetic fields is safe, well tolerated, and shows evidence of antitumour effects in patients with advanced HCC.

Costa, F P; de Oliveira, A C; Meirelles, R; Machado, M C C; Zanesco, T; Surjan, R; Chammas, M C; de Souza Rocha, M; Morgan, D; Cantor, A; Zimmerman, J; Brezovich, I; Kuster, N; Barbault, A; Pasche, B

2011-01-01

43

Controllability of Electromagnetically Induced Transparency in a Doppler Broadened Four-Level Atomic System  

NASA Astrophysics Data System (ADS)

The influence of Doppler broadening on a four-level N-type atomic system has been investigated in the presence of spontaneous generating coherence. The atomic system interacting with three electromagnetic fields and includes the nonradiative decay, the effect of co- and counter-propagation of the fields is considered. The probe susceptibility behaviors can be modified by Doppler broadening via nonperturbative treatments of the density matrix elements solution in the absence and presence of the spontaneous generating coherence. Some interesting features are enhanced for the spectral behaviors and controllability of electromagnetically induced transparency, which were found to be in good agreement to some experimental results without including Zeeman sublevels to the system.

Abd-Elnabi, Somia; Osman, K. I.

2013-04-01

44

Electromagnetically induced transparency in an inhomogeneously broadened {Lambda} transition with multiple excited levels  

SciTech Connect

Electromagnetically induced transparency (EIT) has mainly been modeled for three-level systems. In particular, considerable interest has been dedicated to the {Lambda} configuration, with two ground states and one excited state. However, in the alkali-metal atoms, which are commonly used, the hyperfine interaction in the excited state introduces several levels which simultaneously participate in the scattering process. When the Doppler broadening is comparable with the hyperfine splitting in the upper state, the three-level {Lambda} model does not reproduce the experimental results. Here we theoretically investigate the EIT in a hot vapor of alkali-metal atoms and demonstrate that it can be strongly reduced by the presence of multiple excited levels. Given this model, we also show that well-designed optical pumping enables us to significantly recover the transparency.

Mishina, O. S.; Scherman, M.; Lombardi, P.; Ortalo, J.; Bramati, A.; Laurat, J.; Giacobino, E. [Laboratoire Kastler Brossel, Universite Pierre et Marie Curie, Ecole Normale Superieure, CNRS, Case 74, 4 place Jussieu, F-75252 Paris Cedex 05 (France); Felinto, D. [Departamento de Fisica, Universidade Federal de Pernambuco, 50670-901 Recife, PE (Brazil); Sheremet, A. S.; Kupriyanov, D. V. [Department of Theoretical Physics, State Polytechnic University, 195251, St. Petersburg (Russian Federation)

2011-05-15

45

Electromagnetically Induced Transparency in Cesium Vapor with Probe Pulses on the Single-Photon Level  

SciTech Connect

We perform electromagnetically induced transparency (EIT) experiments in cesium vapor with pulses on the single-photon level for the first time. This was made possible by an extremely large total suppression of the EIT coupling beam by 118 dB mainly due to a newly developed triple-pass planar Fabry-Perot etalon filter. Slowing and shaping of single-photon light pulses as well as the generation of pulses suitable for quantum key distribution applications and testing of approaches for single photon storage is demonstrated. Our results extend single-photon EIT to the particularly interesting wavelength of the Cs D1 line.

Hoeckel, David; Benson, Oliver [Nano Optics, Institute of Physics, Humboldt-Universitaet zu Berlin, Hausvogteiplatz 5-7 10117 Berlin (Germany)

2010-10-08

46

Observation of an electromagnetically induced grating in cold sodium atoms  

Microsoft Academic Search

We have observed diffraction signals by a grating originating from electromagnetically induced transparency (EIT) in a three-level Lambda system of cold sodium atoms. Theoretical and experimental analyses of this phenomenon, called the electromagnetically induced grating (EIG), have revealed that EIG spectra exhibit background-free, Lorentzian signal profiles regardless of the pump frequencies, making a clear contrast to the case of ordinary

Masaharu Mitsunaga; Nobuyuki Imoto

1999-01-01

47

Tuning out vibrational levels in molecular electron energy-loss spectra  

NASA Astrophysics Data System (ADS)

The phenomenon whereby features associated with certain vibrational levels in molecular states of mixed electronic character disappear under specific scattering conditions in electron energy-loss spectra is investigated. In particular, using a combination of experimental measurements and coupled-channel calculations, anomalous vibrational intensities in the mixed valence-Rydberg 1?u?X1?g+ transition of N2 are explained. A single parameter, i.e., the ratio of the generalized electronic transition moments to the diabatic valence and Rydberg components of the mixed states, dependent on the experimental scattering conditions, is found to be essentially capable of describing all observed relative vibrational intensities, including the near disappearance of the b1?u(v=5) feature for momentum-transfer-squared values K2?0.3 a.u. This result highlights the interesting possibility of experimental control of molecular quantum-interference effects in electron energy-loss spectra, something that is not possible in optical spectra.

Heays, A. N.; Lewis, B. R.; Gibson, S. T.; Malone, C. P.; Johnson, P. V.; Kanik, I.; Khakoo, M. A.

2012-01-01

48

Absorption spectra of pulse-train-excited sodium two-level atoms  

NASA Astrophysics Data System (ADS)

The steady-state absorption of a beam of sodium atoms irradiated by a train of pulses from a mode-locked dye laser has been measured. The sodium atoms were prepared as two-level systems by optical pumping with a two-mode laser. Absorption spectra on the 589.0-nm D2 line were recorded over 20 GHz with a frequency-stabilized, tunable, mode-locked dye laser having a bandwidth of 3.7 GHz and a mode spacing of 82 MHz. The laser-pulse profile was determined from the spectral profile assuming transform-limited pulses and was incorporated in theoretical calculations of excitation spectra obtained by numerical integration of the optical Bloch equations. By comparison of measured absorption spectra and theoretical excitation spectra the validity of the weak-field solution as well as the predicted saturation behavior were fully verified by the experimental results. For the highest level of irradiation applied, the laser pulses were identified as pi pulses.

Krüger, E.

1995-01-01

49

Modeling hyperspectral observations of vegetation fluorescence from photosystem level to top-of-atmosphere radiance spectra  

NASA Astrophysics Data System (ADS)

In support of the candidate ESA mission FLEX, models have been developed to simulate vegetation chlorophyll fluorescence and its observation on the level of single leaves, the canopy and from space. The Fluspect model is based on the PROSPECT leaf model and includes an additional module which calculates the excitation-fluorescence matrix for both sides of the leaf by means of an efficient doubling algorithm. Fluorescence spectra for white incident light, and of course the spectra of reflectance and transmittance, are computed as well. The FluorSAIL model is a numerical variant of SAIL which calculates top-of-canopy fluorescent radiance in the direction of viewing for given incident radiation spectra from the sun and the sky, obtained from the MODTRAN radiative transfer code. In a recent version called FluorSAIL3, high spectral resolution data (0.1 nm) from MODTRAN5 (beta) are used by the model to simulate observations by the candidate FLEX mission. The model computes the directional canopy reflectance with and without fluorescence for the given incident radiation spectra obtained from MODTRAN and the results have been used to evaluate several algorithms for the retrieval of fluorescence from the apparent reflectance signal. In this contribution emphasis will be on the detection of the fluorescence signal, the dependence of fluorescence observations on leaf chlorophyll content and other PROSPECT parameters, canopy structure, and observational conditions, including the properties of the atmosphere. In addition, some attention is paid to the definition of fluorescence quantum efficiencies at photosystem level, leaf level, and canopy level. This is important for the study of the relation between canopy fluorescence and actual photosynthesis. From the simulations it can be concluded that the interpretation of the fluorescence signal is complex, and probably the comparison of actual observations of spectra of fluorescence and reflectance with spectra simulated by a coupled chain of models such as Fluspect-FluorSAIL-MODTRAN will be of great help in drawing the correct conclusions from observations by a mission like FLEX.

Verhoef, W.

2011-12-01

50

The extension of gain spectra and accurate determination of the quasi-Fermi-level separation from measured amplified spontaneous emission spectra  

NASA Astrophysics Data System (ADS)

A method for obtaining the gain spectra of semiconductor lasers in an extended energy range from amplified spontaneous emission (ASE) spectra is presented. Hakki-Paoli gain measurement is first used to determine the quasi-Fermi-level separation. By using the fitting process proposed, a self-consistent correction in determining quasi-Fermi separation leads to a reduced error (<1 meV) and a recalibration of the intrinsic absorption coefficient is also self-consistently possible. Subsequently, with measured gain in a restricted energy range, we can obtain gain spectra in a much wider energy range by our proposed algorithm in conjunction with ASE data. The application of this method in obtaining the extended gain spectra of a double-quantum-well GaInP ridge waveguide laser is demonstrated.

Fu, Liwei; Wu, Linzhang; Schweizer, Heinz

1999-11-01

51

Improved IC Production Yield by Taking Into Account the Electromagnetic Interference Level During Testing  

Microsoft Academic Search

This paper presents a novel method for detecting test errors in radio frequency integrated circuit (RFIC) autotest- equipment (ATE) caused by electromagnetic interferences. A sen- sor for measuring ambient electromagnetic (EM) signals was used to determine whether interference was the cause of the reported testing error. Upon detecting a testing error, a retest procedure was actuated to recover the testing

Cheng-Nan Hu; Hsuan-Chung Ko

2011-01-01

52

Explaining Electromagnetic Plane Waves in a Vacuum at the Introductory Level  

ERIC Educational Resources Information Center

A typical introduction to electromagnetic waves in vacuum is illustrated by the following quote from an introductory physics text: "Maxwell's equations predict that an electromagnetic wave consists of oscillating electric and magnetic fields. The changing fields induce each other, which maintains the propagation of the wave; a changing electric…

Allred, Clark L.; Della-Rose, Devin J.; Flusche, Brian M.; Kiziah, Rex R.; Lee, David J.

2010-01-01

53

Evaluation of shielding effectiveness on system level by electromagnetic topology based modeling  

Microsoft Academic Search

The confidence in shielding effectiveness (SE) measurements on enclosures according to IEC TS 61587-3 is evaluated. A methodical analysis using an electromagnetic topology (EMT) based model is carried out to find the electromagnetic (EM) critical aspects. The EMT model represents the interaction between base and auxiliary components which are necessary for testing. As shown in examples, each local coupling effect

C. A. Monje; S. Helmers; E. G. Diez

2005-01-01

54

Magnetic breakdown and Landau level spectra of a tunable double-quantum-well Fermi surface  

SciTech Connect

By measuring longitudinal resistance, the authors map the Landau level spectra of double quantum wells as a function of both parallel (B{sub {parallel}}) and perpendicular (B{sub {perpendicular}}) magnetic fields. In this continuously tunable highly non-parabolic system, the cyclotron masses of the two Fermi surface orbits change in opposite directions with B{sub {parallel}}. This causes the two corresponding ladders of Landau levels formed at finite B{sub {perpendicular}} to exhibit multiple crossings. They also observe a third set of landau levels, independent of B{sub {parallel}}, which arise from magnetic breakdown of the Fermi surface. Both semiclassical and full quantum mechanical calculations show good agreement with the data.

Simmons, J.A.; Harff, N.E.; Lyo, S.K.; Klem, J.F. [Sandia National Labs., Albuquerque, NM (United States); Boebinger, G.S.; Pfeiffer, L.N.; West, K.W. [Lucent Technologies, Murray Hill, NJ (United States). Bell Labs.

1997-12-31

55

Nuclear-level densities around Z = 50 from neutron evaporation spectra in (p, n) reactions  

SciTech Connect

Neutron excitation functions, spectra, and angular distributions in the (p, n) reactions on the isotopes {sup 116}Sn, {sup 118}Sn, {sup 122}Sn, and {sup 124}Sn were measured in the proton-energy range 7-11 MeV. The measurements were performed by the time-of-flight method with the aid of a fast-neutron spectrometer at the EGP-15 pulsed tandem accelerator of the Institute of Physics and Power Engineering (Obninsk). A high resolution (about 0.6 ns/m) and a high stability of the time-of-flight spectrometer made it possible to identify reliably low-lying levels along with the continuous section of the neutron spectra. The data obtained in this way were analyzed on the basis of the statistical equilibrium and preequilibrium models of nuclear reactions. The respective calculations were performed with the aid of the precise Hauser-Feshbach formalism of statistical theory. The nuclear-level densities in the isotopes {sup 116}Sb, {sup 118}Sb, {sup 122}Sb, and {sup 124}Sb were determined, along with their energy dependences and model parameters. In the excitation-energy range 0-2 MeV, the energy dependence of the nuclear-level densities exhibits a structure that is associated with the shell inhomogeneities of the spectrum of single-particle states near filled shells. The isotopic dependence of the nuclear-level density is discovered and explained. It is also shown that the data obtained here for the nuclear-level density differ markedly from the predictions of model systematics of nuclear-level densities.

Zhuravlev, B. V.; Lychagin, A. A.; Titarenko, N. N. [Institute for Physics and Power Engineering (Russian Federation)

2006-03-15

56

Investigation of the levels of electromagnetic radiation generated by wind turbines.  

National Technical Information Service (NTIS)

The issue of electromagnetic interference is arising with some regularity as various wind energy projects throughout the UK reach the stage where local authority planning approval is sought. To many of the parties involved, wind turbines represent an unkn...

C. A. Morgan

1992-01-01

57

GRABGAM: A Gamma Analysis Code for Ultra-Low-Level HPGe SPECTRA  

SciTech Connect

The GRABGAM code has been developed for analysis of ultra-low-level HPGe gamma spectra. The code employs three different size filters for the peak search, where the largest filter provides best sensitivity for identifying low-level peaks and the smallest filter has the best resolution for distinguishing peaks within a multiplet. GRABGAM basically generates an integral probability F-function for each singlet or multiplet peak analysis, bypassing the usual peak fitting analysis for a differential f-function probability model. Because F is defined by the peak data, statistical limitations for peak fitting are avoided; however, the F-function does provide generic values for peak centroid, full width at half maximum, and tail that are consistent with a Gaussian formalism. GRABGAM has successfully analyzed over 10,000 customer samples, and it interfaces with a variety of supplementary codes for deriving detector efficiencies, backgrounds, and quality checks.

Winn, W.G.

1999-07-28

58

Spectra From Space : Main Menu  

NSDL National Science Digital Library

On-line science lesson (grades 7 - 9) - students learn about satellite spectra research, electromagnetic spectrum, do hands-on activities. In this lesson students investigate satellite missions operating in four electromagnetic bands. Students learn about spectra and why satellites gather certain kinds of spectra from space by using the Internet and doing hands-on activities. From the University of California, Berkeley.

1997-01-01

59

Large-scale Bethe-Salpeter equation calculations of core-level x-ray spectra  

NASA Astrophysics Data System (ADS)

Recently an approach has been developed for Bethe-Salpeter equation (BSE) calculations of core-level x-ray spectra, which is implemented in the ocean package footnotetext J. Vinson, E. L. Shirley, J. J. Rehr, and J. J. Kas, Phys. Rev. B 83, 115106 (2011); J. Vinson and J. J. Rehr, Phys. Rev. B (in press , 2012) which combines plane-wave, pseudopotential DFT electronic structure, PAW transition elements, GW self-energy corrections, and the NIST BSE solver. The method yields both dipole limited and finite momentum transfer spectra. Here we discuss several recent advances which yield a unified treatment of both extended states and atomic multiplet effects. In particular our approach now includes spin-dependent potentials and hole-dependent lifetimes, and gives an improved treatment of L2,3 edges, where contributions to spectral weight come from a mix of two distinct core holes. We have also extended the code interface to include pseudopotential wave functions from abinit, QuantumEspresso, or an interpolation based scheme, thus enabling large-scale calculations with unit cells in excess of 2000 å^3. Applications to water and ice structures are briefly discussed.

Rehr, J. J.; Vinson, J.; Gilmore, K.

2013-03-01

60

Two-level refined direct optimization scheme using intermediate surrogate models for electromagnetic optimization of a switched reluctance motor  

Microsoft Academic Search

Electromagnetic optimization procedures require a large number of evaluations in numerical forward models. These computer\\u000a models simulate complex problems through the use of numerical techniques, e.g. finite elements. Hence, the evaluations need\\u000a a large computational time. Two-level methods such as space mapping have been developed that include a second model so as\\u000a to accelerate the inverse procedures. Contrary to existing

Guillaume Crevecoeur; Ahmed Abou-Elyazied Abdallh; Ivo Couckuyt; Luc Dupré; Tom Dhaene

61

Electromagnetically induced transparency in Doppler-broadened three-level systems with resonant standing-wave drive  

Microsoft Academic Search

We study electromagnetically induced transparency for a probe travelling-wave (TW) laser field in closed Doppler-broadened three-level systems driven by a resonant standing-wave (SW) laser field of moderate intensity (its Rabi frequencies are smaller than the Doppler width of the driven transition). We show that probe windows of transparency occur only for values of the probe-to-drive field frequency ratio R close

F. Silva; J. Mompart; V. Ahufinger; R. Corbalán

2000-01-01

62

Electric-Dipole{endash}Quadrupole Interference of Overlapping Autoionizing Levels in Photoelectron Energy Spectra  

SciTech Connect

We have measured the photon energy dependence of electric-dipole{endash}quadrupole interference in cadmium between the odd parity 4d{sup 9}5s{sup 2}5p J=1 and even parity 5p6p {sup 3} P{sub 2} autoionizing levels. The resonant interference structure is isolated by taking the difference between constant ionic state spectra at 45{degree} with respect to the photon beam in the forward and backward directions. We find interference effects that are approximately 0.5{percent} of the dipole cross section for photon energies of 13thinspeV, in good agreement with theory. We compare the results with those from (e,thinsp2e) experiments. {copyright} {ital 1998} {ital The American Physical Society }

Martin, N.L.; Thompson, D.B.; Bauman, R.P. [Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506-0055 (United States); Caldwell, C.D.; Krause, M.O.; Frigo, S.P. [Department of Physics, University of Central Florida, Orlando, Florida 32816 (United States); Wilson, M. [Physics Department, Royal Holloway, University of London, Egham, Surrey TW20 0EX (United Kingdom)

1998-08-01

63

The Modeling Method of Interference Source of System-level Electromagnetic Compatibility  

Microsoft Academic Search

In order to improve and reinforce the facilities with problems on electromagnetic compatibility, it is inevitable to get down to the suppression and improvement to the interference source first. If the computer modeling to the interference source could be undertaken before the correctness, then by means of simulation the best method is to be found to improve facilities, as a

Wang Longfeng; Su Donglin; Chen Wenqing; Zhang Xiuqiang

2007-01-01

64

Modeling Electromagnetic signal levels falling on aircraft from satellite communication systems  

Microsoft Academic Search

To this end, this paper proposes a novel study that computationally models the electromagnetic effects incident on aircraft fuselage from external high frequency sources. An accurate ray-tracing framework was employed for the assessment of the power incident from a terrestrially based Ka-band antenna onto a small sized aircraft whilst flying. Subsequent to the determination of an illumination cone technique, to

Clifford De Raffaele; Carl J. Debono; Adrian Muscat

2011-01-01

65

Electromagnetic Topology: a Modular Junction Approach for a System Level Interaction Problem  

Microsoft Academic Search

A new approach to perform electromagnetic topology based simulation is proposed by incorporating modular scattering junction concept. This method substitutes the multi- step computation technique and is convenient to implement. The method also allows for incorporating substructural modifications and does not require repeating solutions to the entire system. The overall simulation utilizes transmission line matrix compaction, finite-difference time-domain method, and

Phumin Kirawanich; Justin Wilson; N. E. Islam; Christos Christodoulou; S. J. Yakura

2007-01-01

66

Energy Spectra, Composition, and Other Properties of Ground-Level Events During Solar Cycle 23  

NASA Astrophysics Data System (ADS)

We report spacecraft measurements of the energy spectra of solar protons and other solar energetic particle properties during the 16 Ground Level Events (GLEs) of Solar Cycle 23. The measurements were made by eight instruments on the ACE, GOES, SAMPEX, and STEREO spacecraft and extend from ˜0.1 to ˜500-700 MeV. All of the proton spectra exhibit spectral breaks at energies ranging from ˜2 to ˜46 MeV and all are well fit by a double power-law shape. A comparison of GLE events with a larger sample of other solar energetic particle (SEP) events shows that the typical spectral indices are harder in GLE events, with a mean slope of -3.18 at >40 MeV/nuc. In the energy range 45 to 80 MeV/nucleon about ˜50 % of GLE events have properties in common with impulsive 3He-rich SEP events, including enrichments in Ne/O, Fe/O, 22Ne/20Ne, and elevated mean charge states of Fe. These 3He-rich events contribute to the seed population accelerated by CME-driven shocks. An analysis is presented of whether highly-ionized Fe ions observed in five events could be due to electron stripping during shock acceleration in the low corona. Making use of stripping calculations by others and a coronal density model, we can account for events with mean Fe charge states of < Q Fe>?+20 if the acceleration starts at ˜1.24-1.6 solar radii, consistent with recent comparisons of CME trajectories and type-II radio bursts. In addition, we suggest that gradual stripping of remnant ions from earlier large SEP events may also contribute a highly-ionized suprathermal seed population. We also discuss how observed SEP spectral slopes relate to the energetics of particle acceleration in GLE and other large SEP events.

Mewaldt, R. A.; Looper, M. D.; Cohen, C. M. S.; Haggerty, D. K.; Labrador, A. W.; Leske, R. A.; Mason, G. M.; Mazur, J. E.; von Rosenvinge, T. T.

2012-10-01

67

Probe absorption dispersion spectra of a driven three-level atom in a double-band photonic crystal  

Microsoft Academic Search

The probe absorption dispersion spectra of a driven three-level atom in a double-band photonic crystal have been investigated. We use the model which assumes the upper levels of the atomic transitions coupled via a classical driving field. One of the transitions interacts with the free vacuum modes, and the other transition couples to the modes of the modified reservoir (photonic

S. Roshan Entezar; H. Tajalli

2006-01-01

68

Electromagnetic field levels in the working environment in radio and TV stations  

Microsoft Academic Search

Electromagnetic field sources used for communication always have been subject of serious interest. There are many publications\\u000a concerning exposure and risk assessment of the working in such environment. Results of epidemiological study performed in\\u000a Bulgaria in the 1990's show exceeding of the maximal permissible values especially in radio stations for the personnel in\\u000a 24 h working shift [Israel et al. (1992). Study

M. Ivanova; V. Zaryabova; Ts. Shalamanova; M. Israel

2007-01-01

69

Measurements of gamma radiation levels and spectra in the San Francisco Bay Area  

NASA Astrophysics Data System (ADS)

Much of the radiation received by an average person is emitted by naturally-occurring radioactive isotopes from the thorium, actinium, and uranium decay series, or potassium. In this study, we have measured gamma radiation levels at various locations in the San Francisco Bay Area and the UC Berkeley campus from spectra taken using an ORTEC NOMAD portable data acquisition system and a large-volume coaxial HPGe detector. We have identified a large number of gamma rays originating from natural sources. The most noticeable isotopes are ^214Bi, ^40K, and ^208Tl. We have observed variations in counting rates by factors of two to five between different locations due to differences in local conditions -- such as building, concrete, grass, and soil compositions. In addition, in a number of outdoor locations, we have observed 604-, 662-, and 795-keV gamma rays from ^134,137Cs, which we attribute to fallout from the recent Fukushima reactor accident. The implications of these results will be discussed.

Lo, B. T.; Brozek, K. P.; Angell, C. T.; Norman, E. B.

2011-10-01

70

Specific distribution of the noise electromagnetic field level at high latitudes in the vicinity of the first Schumann resonance  

NASA Astrophysics Data System (ADS)

The distributions of the natural noise electromagnetic field level in the vicinity of the first Schumann resonance have been studied based on data from Lovozero observatory (the Kola Peninsula). Daily curves of noise level excesses over specified thresholds at different geomagnetic disturbances have been constructed. It has been indicated that the curves are morphologically similar on magnetically quiet days but are highly variable from day to day, although the averaged curves are similar in some characteristics to the unitary variation in the surface quasistatic electric field. The possibilities of applying the known formula for the probability distribution of the VLF atmospheric radio noise amplitude in order to analytically describe the noise level probability distribution have been considered. It has been detected that geomagnetic disturbances pronouncedly affect the distribution parameters, sharply increasing the amount of large-amplitude noise.

Beloglazov, M. I.; Pchelkin, V. V.

2011-10-01

71

Electromagnetically induced transparency of single ?-type three-level atoms in a high-finesse optical cavity  

NASA Astrophysics Data System (ADS)

We study the features of electromagnetically induced transparency (EIT) in a single ?-type three-level atom placed in a high-finesse cavity under the action of a coupling laser and a probe laser. Our calculations show that three transparency windows appear when the pump strength is large enough. This can be explained by the residual pump in the cavity mostly resulting in energy splitting. The level |3> is split into four slightly different energy levels, and interference takes place between the excitation pathways. Furthermore, it is also shown that the frequencies of the EIT windows can be tuned by changing the coupling field detuning ?2, and that the reflection profile is very sensitive to the cavity field detuning ?c.

Sun, Yan-Fen; Tan, Lei; Xu, Yan

2013-03-01

72

Time-resolved Fourier transform infrared spectra of Sr: h-, g-levels and oscillator strengths  

NASA Astrophysics Data System (ADS)

We study spectra of a plasma created by the laser ablation of SrF2 targets in a vacuum and report 19 Sr I lines in the range of 1300-5000 cm-1 which have not been observed before. From the recorded spectra we determine the previously unknown excitation energies of 5 g, 6 g and 6 h states of Sr I. We also calculate a large list of transition probabilities and oscillator strengths for Sr I in the observed spectral range. These A- and f-values are calculated using quantum defect theory which shows good agreement with the available experimental and theoretical results.

Civiš, S.; Ferus, M.; Chernov, V. E.; Zanozina, E. M.; Juha, L.

2013-11-01

73

Local Modulation of Double Electromagnetically Induced Transparency Spectrum  

Microsoft Academic Search

The double electromagnetically induced transparency induced by two coupling fields can be realized in a four-level tripod-type atom. Such double transparency spectra can be locally modulated by using the weak coherent fields to perturb the coupling transitions. These investigations within this scheme can be independent of Doppler broadening by properly orienting these fields.

Bang-Pin Hou; Shun-Jin Wang; Wan-Lun Yu; Wei-Li Sun

2007-01-01

74

Electromagnetic remote sensing. Low frequency electromagnetics  

NASA Astrophysics Data System (ADS)

A series of lectures are presented on the topic of the location and identification of compact objects by low frequency electromagnetics. These lectures were presented as a portion of two graduate level courses in electrical engineering at the University of Toronto in 1985 and 1987. Magnetostatics, electrostatics and electromagnetic induction techniques are discussed in detail.

McFee, John E.

1989-01-01

75

Rovibrational Energy Levels and Photoabsorption Spectra of the Isotopically Substituted N2O: A Theoretical Study  

Microsoft Academic Search

ABSTRACT The rovibrational spectra of the ground electronic state potential energy surface, X , for the ,1. Dengan menggunakan fungsi gelombang dari lima isotopomer,berat and pemindahan,momen,berkutub yang menghubungkan,kepada,tiga keadaan,terendah permukaan tenaga keupayaan singlet (2 , 1 dan 2 ), hasilan spektrum -spektrum penyerapan teori menunjukkan,persetujuan yang sangat baik dengan spektrum-spektum eksperimen. (Variational, potential energy surfaces, Jacobi coordinate, rovibrational energy, ultraviolet

Mohammad Noh Daud; Gabriel G. Balint-Kurti

2009-01-01

76

Dynamics of a trapped two-level and three-level atom interacting with classical electromagnetic field  

Microsoft Academic Search

The dynamics of a two-level atom driven by a single laser beam and three-level atom (Lambda configuration) irradiated by two laser beams are studied taking into account of the quantized center-of-mass motion of the atom. It is shown that the trapped atom system under appropriate resonance condition exhibits the large time-scale revivals when the index of the vibrational sideband responsible

Aditi Ray; Aditi

2004-01-01

77

Hierarchical Two-level Preconditioning of MLFMA Algorithm for Electromagnetic Wave Scattering Problems  

Microsoft Academic Search

A set of higher order hierarchical basis functions is proposed for expansion of the current in electrical field integral equations (EFIE) solved by multilevel fast multipole algorithm (MLFMA). The hierarchical two-level spectral preconditioning technique is developed to solve EFIE in radar cross section (RCS) calculations. This newly constructed hierarchical two-level spectral preconditioner is used to speed up the restarted GMRES

S. S. Li; Y. Yang; R. S. Chen; T. Ke

2007-01-01

78

Children and adults exposed to electromagnetic fields at the ICNIRP reference levels: theoretical assessment of the induced peak temperature increase.  

PubMed

To avoid potentially adverse health effects of electromagnetic fields (EMF), the International Commission on Non-Ionizing Radiation Protection (ICNIRP) has defined EMF reference levels. Restrictions on induced whole-body-averaged specific absorption rate (SAR(wb)) are provided to keep the whole-body temperature increase (T(body, incr)) under 1 °C during 30 min. Additional restrictions on the peak 10 g spatial-averaged SAR (SAR(10g)) are provided to prevent excessive localized tissue heating. The objective of this study is to assess the localized peak temperature increase (T(incr, max)) in children upon exposure at the reference levels. Finite-difference time-domain modeling was used to calculate T(incr, max) in six children and two adults exposed to orthogonal plane-wave configurations. We performed a sensitivity study and Monte Carlo analysis to assess the uncertainty of the results. Considering the uncertainties in the model parameters, we found that a peak temperature increase as high as 1 °C can occur for worst-case scenarios at the ICNIRP reference levels. Since the guidelines are deduced from temperature increase, we used T(incr, max) as being a better metric to prevent excessive localized tissue heating instead of localized peak SAR. However, we note that the exposure time should also be considered in future guidelines. Hence, we advise defining limits on T(incr, max) for specified durations of exposure. PMID:21772085

Bakker, J F; Paulides, M M; Neufeld, E; Christ, A; Kuster, N; van Rhoon, G C

2011-07-19

79

On the use of auxiliary vector potentials as a common tool for studying electromagnetic problems at undergraduate level  

Microsoft Academic Search

Applications of Maxwell's equations to electromagnetic problems can be divided into two large groups: one dealing with radiation and scattering and the other with propagation. In this paper it is shown how both kinds of problem can be managed by means of the auxiliary vector potentials and . The electromagnetic behaviour of physical phenomena is described by Maxwell's equations. An

Miguel A. Solano; Ángel Vegas; Álvaro Gómez

80

Dynamics of a trapped two-level and three-level atom interacting with classical electromagnetic field  

SciTech Connect

The dynamics of a two-level atom driven by a single laser beam and three-level atom (Lambda configuration) irradiated by two laser beams are studied taking into account of the quantized center-of-mass motion of the atom. It is shown that the trapped atom system under appropriate resonance condition exhibits the large time-scale revivals when the index of the vibrational sideband responsible for the atomic electronic transition is greater than unity. The revival times are shown to be dependent on the initial number of vibrational excitations and the magnitude of the Lamb-Dicke parameter. The sub-Poissonian statistics in vibrational quantum number is observed at certain time intervals. The minimum time of interaction for which the squeezed states of motional quadrature are generated is found to be decreasing with the increase in the Lamb-Dicke parameter.

Ray, Aditi [Theoretical Physics Division, Bhabha Atomic Research Centre, Mumbai-400085 (India)

2004-03-01

81

[Autoimmune processes after long-term low-level exposure to electromagnetic fields (the results of an experiment). Part 1. Mobile communications and changes in electromagnetic conditions for the population. Needs for additional substantiation of the existing hygienic standards].  

PubMed

Mobile communications provides a new source of electromagnetic exposure for almost the whole population of the Russian Federation. For the first time in the history of civilization the brain of mobile phone users was exposed to localized radiofrequency (RF) electromagnetic fields (EMF). Population exposure from the base stations is also considered to be specific. However, existing standards for limiting the exposure do not account for this special EMF source and may not ensure the absence of health effects. There was a need for reliable information that would extend databases used for development of new standards. As recommended by the World Health Organization an additional experiment was performed under the supervision of foreign experts, which showed changes in autoimmune status in rats after long-term low-level RF EMF exposure with an incident power density of 500 microW/cm2. PMID:20297674

Grigor'ev, Iu G; Grigor'ev, O A; Ivanov, A A; Liaginskaia, A M; Merkulov, A V; Stepanov, V S; Shagina, N B

82

Calculation of core-level photoemission spectra of Mn films on Ag(001)  

NASA Astrophysics Data System (ADS)

We report a theoretical study of Mn 2p photoemission spectra for Mn thin films adsorbed on Ag(001), for which large satellites have recently been observed. Band structure calculations are performed to determine the ground-state electronic structure. The band structure information is then used to construct a realistic impurity model that includes full atomic multiplet interaction and coupling to the Mn-3d and Ag-4d bands. The model is applied to various Mn/Ag thin film structures, whereby only the most relevant model parameter, the hybridization strength, is varied using a simple scaling law. Good agreement with experiment is obtained for all systems. It is found that the satellite structure is due to the presence of (2p53d5) and (2p53d6L¯) final states, where the ligand hole L¯ is mainly in the majority spin Mn band of the neighbors. It is shown that atomic multiplet effects cause an apparent spin-orbit splitting that is greater for (2p53d5) than for (2p53d6) final states, which leads to a 1 eV larger main line to satellite splittings for the 2p1/2 lines than for the 2p3/2 lines in agreement with experiment.

Krüger, P.; Kotani, A.

2003-07-01

83

Level density fluctuations and characterization of chaos in the realistic model spectra for odd-odd nuclei  

NASA Astrophysics Data System (ADS)

Statistical properties of the realistic energy spectra of the odd-odd nuclei106Ag,198Au,134Cs,40K and94Rb, calculated within the Interacting Boson Fermion Fermion Model, are investigated by means of the ? 3 statistics and the Nearest Neighbor Spacing Distribution method. New probability distribution function, which describes well the calculated results and enables the characterization of chaos with a physically meaningfull parameter, is proposed. Level spacing fluctuations of the examined nuclei exhibit the transitional behavior between Poisson and GOE limits, revealing different degrees of chaoticity in their dynamics.

Lopac, V.; Brant, S.; Paar, V.

1996-12-01

84

Project Spectra!  

NSDL National Science Digital Library

This is an electromagnetic spectrum science program that incorporates engineering, math, and solar system data stories that use mission data to explain how light is used to explore the solar system. A set of foundational lessons accompanies the program, helping students understand spectroscopy at a basic level. The data stories include paper and pencil versions, as well as Flash-based interactives where students delve more deeply into the missions and science behind the data.

2009-12-01

85

Preconditioned iterative solver on the coarsest level of a multi-grid method for high frequency time harmonic electromagnetic field analyses  

Microsoft Academic Search

A multi-grid method is one of the most powerful linear solvers for finite element electromagnetic field analysis. However,\\u000a as the discretized model has recently been enlarged, a solution process for a linear system arising on the coarsest level\\u000a tends to be problematic in a complete multi-grid solution process. Whereas a linear system on the coarsest level is generally\\u000a solved by

T. Iwashita; K. Yosui; M. Mori; E. Kobayashi; S. Abe

2008-01-01

86

Effects of simultaneous combined exposure to CDMA and WCDMA electromagnetic fields on serum hormone levels in rats  

PubMed Central

Despite more than a decade of research on the endocrine system, there have been no published studies about the effects of concurrent exposure of radiofrequency electromagnetic fields (RF-EMF) on this system. The present study investigated the several parameters of the endocrine system including melatonin, thyroid stimulating hormone, stress hormone and sex hormone after code division multiple access (CDMA, 849 MHz) and wideband code division multiple access (WCDMA, 1.95 GHz) signals for simultaneous exposure in rats. Sprague-Dawley rats were exposed to RF-EMF signals for 45 min/day, 5 days/week for up to 8 weeks. The whole-body average specific absorption rate (SAR) of CDMA or WCDMA was 2.0 W/kg (total 4.0 W/kg). At 4 and 8 weeks after the experiment began, each experimental group's 40 rats (male 20, female 20) were autopsied. Exposure for 8 weeks to simultaneous CDMA and WCDMA RF did not affect serum levels in rats of melatonin, thyroid stimulating hormone (TSH), triiodothyronine (T3) and thyroxin (T4), adrenocorticotropic hormone (ACTH) and sex hormones (testosterone and estrogen) as assessed by the ELISA method.

Jin, Yeung Bae; Choi, Hyung-Do; Kim, Byung Chan; Pack, Jeong-Ki; Kim, Nam; Lee, Yun-Sil

2013-01-01

87

Probing Majorana modes in the tunneling spectra of a resonant level.  

PubMed

Unambiguous identification of Majorana physics presents an outstanding problem whose solution could render topological quantum computing feasible. We develop a numerical approach to treat finite-size superconducting chains supporting Majorana modes, which is based on iterative application of a two-site Bogoliubov transformation. We demonstrate the applicability of the method by studying a resonant level attached to the superconductor subject to external perturbations. In the topological phase, we show that the spectrum of a single resonant level allows us to distinguish peaks coming from Majorana physics from the Kondo resonance. PMID:24172294

Korytár, R; Schmitteckert, P

2013-10-31

88

Low-level laser therapy vs. pulsed electromagnetic field on neonatal rat calvarial osteoblast-like cells.  

PubMed

To compare the effects of pulsed electromagnetic field (PEMF) and low-level laser therapy (LLLT) on osteoblast cells in a cell culture model. Fifty thousand neonatal rat calvarial osteoblast-like cells per milliliter were seeded and 0.06 mT PEMF, 0.2 mT PEMF, and LLLT at 808 nm were applied for 24 and 96 h on the cells. To evaluate cellular proliferation and differentiation, specimens were examined for DNA synthesis, alkaline phosphatase (ALP) activity, cell numbers, and viability of the cells. Morphological appearances of the cells were observed using scanning electron microcopy after 24 and 96 h of incubation. At 24 and 96 h, the control group had a higher cell proliferation than 0.06 and 0.2 mT PEMF groups (p=0.001). At 96 h, 0.2 mT PEMF group had higher cell proliferation rate than 0.06 mT PEMF and LLLT groups (p=0.001). The cell count and cell viability in 0.2 mT PEMF group were higher than the 0.06-mT PEMF and LLLT groups, although these differences were not statistically significant at 96 h (p>0.05). At 24 and 96 h, cell viability in the control group was higher than the test groups. Alkaline phosphatase levels of the groups were comparable in both time intervals (p>0.05). 0.2 mT PEMF application on osteoblast-like cells led to cell proliferation and differentiation better than 0.06 mT PEMF and LLLT at 808 nm, although a remarkable effect of both PEMF and LLLT could not be detected. The ALP activity of 0.2 and 0.06 mT PEMF and LLLT were comparable. PMID:22865122

Emes, Yusuf; Akça, Kivanç; Aybar, Buket; Yalç?n, Serhat; Çavu?o?lu, Yeliz; Baysal, U?ur; I?sever, Halim; Atalay, Belir; Vural, Pervin; Ergüven, Mine; Çehreli, Murat Cavit; Bilir, Ayhan

2012-08-05

89

Electromagnetic leptogenesis  

SciTech Connect

We present a new leptogenesis scenario, where the lepton asymmetry is generated by CP-violating decays of heavy electroweak singlet neutrinos via electromagnetic dipole moment couplings to the ordinary light neutrinos. Akin to the usual scenario where the decays are mediated through Yukawa interactions, we have shown, by explicit calculations, that the desired asymmetry can be produced through the interference of the corresponding tree-level and one-loop decay amplitudes involving the effective dipole moment operators. We also find that the relationship of the leptogenesis scale to the light neutrino masses is similar to that for the standard Yukawa-mediated mechanism.

Bell, Nicole F.; Law, Sandy S. C. [School of Physics, University of Melbourne, Victoria 3010 (Australia); Kayser, Boris J. [Theoretical Physics Department, Fermilab, PO Box 500, Batavia, Illinois 60510-0500 (United States)

2008-10-15

90

Optimal broadening of finite energy spectra in the numerical renormalization group: Application to dissipative dynamics in two-level systems  

NASA Astrophysics Data System (ADS)

Numerical renormalization-group (NRG) calculations of quantum impurity models, based on a logarithmic discretization in energy of electronic or bosonic Hamiltonians, provide a powerful tool to describe physics involving widely separated energy scales, as typically encountered in nanostructures and strongly correlated materials. This main advantage of the NRG was however considered a drawback for resolving sharp spectral features at finite energy, such as dissipative atomic peaks. Surprisingly, we find a bunching of many-body levels in NRG spectra near dissipative resonances, and exploit this by combining the widely used Oliveira’s z trick, using an averaging over few discrete NRG spectra, with an optimized frequency-dependent broadening parameter b(?) . This strategy offers a tremendous gain in computational power and extracts all the needed information from the raw NRG data without a priori knowledge of the various energy scales at play. As an application we investigate with high precision the crossover from coherent to incoherent dynamics in the spin boson model.

Freyn, Axel; Florens, Serge

2009-03-01

91

Effects of 900MHz electromagnetic field emitted from cellular phone on brain oxidative stress and some vitamin levels of guinea pigs  

Microsoft Academic Search

This study was designed to demonstrate the effects of 900-MHz electromagnetic field (EMF) emitted from cellular phone on brain tissue and also blood malondialdehyde (MDA), glutathione (GSH), retinol (vitamin A), vitamin D3 and tocopherol (vitamin E) levels, and catalase (CAT) enzyme activity of guinea pigs. Fourteen male guinea pigs, weighing 500–800 g were randomly divided into one of two experimental groups:

Ismail Meral; Handan Mert; Nihat Mert; Yeter Deger; Ibrahim Yoruk; Ay?en Yetkin; Siddik Keskin

2007-01-01

92

Features of relativistic solar proton spectra derived from ground level enhancement events (GLE) modeling  

NASA Astrophysics Data System (ADS)

With the developed by the authors of a ground level enhancements events (GLE) modeling technique, the modeling study of 35 large GLEs for the period 1956-2006 has been carried out. The basic characteristics of relativistic solar protons (RSP) are obtained: a rigidity (energetic) spectrum, anisotropy axis direction, and pitch angle distributions for each event. It is shown that in nearly all events there existed two components (population) of relativistic solar particles: prompt and delayed. The prompt component (PC) prevails in the beginning of the event. It is characterized by an impulsive profile, strong anisotropy and exponential energetic spectrum. The delayed component (DC) dominates during maximum and decline phases of the events. It has a gradual intensity profile, moderate anisotropy and a power law energetic spectrum. The analysis of the large number GLE shows the value of a characteristic energy in the exponential spectrum of PC has rather stable meaning ~0.5 GeV and well agrees with the spectrum of protons accelerated in an electric field arising during the magnetic reconnection in the solar corona. The value of a spectral exponent of the power law spectrum of DC is distributed from 4 up to 6 with most at 5. This is close to the simulated spectrum arising in the process of stochastic acceleration in turbulent solar plasma.

Vashenyuk, E. V.; Balabin, Yu. V.; Gvozdevsky, B. B.

2011-10-01

93

Simultaneous observation of caviton formation, spiky turbulence, and electromagnetic radiation  

NASA Astrophysics Data System (ADS)

Formation of density cavities, spiky turbulence, and electromagnetic radiation at the plasma frequency and its harmonics are observed simultaneously in the presence of a cold-electron beam. The electrostatic and electromagnetic frequency spectra evolve with the development of cavities.

Cheung, P. Y.; Wong, A. Y.; Darrow, C. B.; Qian, S. J.

1982-05-01

94

Noise levels, spectra, and operational function of an occupied newborn intensive care unit built to meet recommended permissible noise criteria  

NASA Astrophysics Data System (ADS)

A group of clinical experts developed recommended permissible noise criteria for newly constructed or renovated hospital nurseries [Philbin et al., J. Perinatol. 19, 559-563 (2000); R. White, ibid. 23, S1-22 (2003)]. These criteria are based principally on research regarding wake-up thresholds for term newborns and speech interference levels for adults. These criteria are: The overall continuous A-weighted, slow response, sound level at any bed or patient care area shall not exceed: (1) an hourly Leq of 50 dB, (2) an hourly L10 of 55 dB, and (3) a 1-s Lmax of 70 dB. A new hospital building was designed to meet these criteria by using specific acoustical criteria for the structure and space arrangement [J. B. Evans and M. K. Philbin, J. Perinatol. 20, S105-S112 (2000)]. Acoustical criteria for sound isolation, background NC, structural vibration, and reverberation will be presented along with space arrangements that ensure staff efficiency, clinical safety, and family privacy. Post-occupancy measurements of sound levels and spectra along with photographs of a nursery in operation will be presented to illustrate how an ICU can have a quiet, highly functioning intensive care environment while meeting the operational goals and acoustical criteria.

Philbin, M. Kathleen; Evans, Jack B.

2003-10-01

95

A Survey of Proton Spectra and Fluences above 1 GV in Ground-Level Enhanced (GLE) Solar Particle Events  

NASA Astrophysics Data System (ADS)

Proton acceleration to energies above ~500 MeV is a controversial and poorly understood aspect of solar energetic particle (SEP) physics, even though these very high-energy events have been observed with neutron monitors in Ground Level Enhancements (GLEs) for more than 50 years. For 40 of the 66 GLEs reported since 1956, we have derived absolutely-normalized event-integrated proton spectra, using data from the world-wide neutron-monitor network and published neutron-yield functions (Clem & Dorman 2000), under the assumption that the proton spectra can be represented as power-laws in rigidity. We believe this analysis to be the most extensive catalogue of GLE spectra ever assembled. As a check on our results, we have compared the fluences derived from our neutron-monitor analyses to satellite measurements at ~300-700 MeV available from IMP8, SAMPEX, and/or GOES for 28 of the events. We generally find very good agreement (i.e., to within ~50%) with the satellite fluence-measurements. We also find reasonable agreement with time-dependent spectral indices that have been published previously for some of the events (e.g., Lovell et al. 1999, Lockwood et al. 2002, and Plainaki et al. 2007). Compared to spectral indices below ~0.4 GV (~100 MeV), we find no evidence for spectral hardening above ~1 GV, something that might be expected if two independent acceleration mechanisms dominated particle production in these two rigidity ranges. We present distributions of event properties above 1 GV, including event size, spectral indices, and the degree of spectral steepening relative to lower energies. These results should be useful constraints in developing and testing theoretical models of proton acceleration in GLEs. We also briefly discuss the implications of these results for the design of astronaut storm shelters, whose efficacy has often been evaluated assuming spectral shapes that are much softer than the ones we derive from the neutron-monitor data. Supported by the Office of Naval Research and by NASA DPR NNG06EC55I.

Tylka, A. J.; Dietrich, W. F.

2008-05-01

96

Analytical solution for the Mollow and Autler-Townes probe absorption spectra of a three-level atom in a squeezed vacuum  

Microsoft Academic Search

The Mollow and Autler-Townes probe absorption spectra of a three-level atom in a cascade configuration with the lower transition coherently driven and also coupled to a narrow bandwidth squeezed-vacuum field are studied. Analytical studies of the modifications caused by the finite squeezed-vacuum bandwidth to the spectra are made for the case when the Rabi frequency of the driving field is

M. Bosticky; Z. Ficek; B. J. Dalton

1998-01-01

97

Electromagnetic field structure and normal mode coupling in photonic crystal nanocavities  

NASA Astrophysics Data System (ADS)

The electromagnetic field of a high-quality photonic crystal nanocavity is computed using the finite difference time domain method. It is shown that a separatrix occurs in the local energy flux discriminating between predominantly near and far field components. Placing a two-level atom into the cavity leads to characteristic field modifications and normal-mode splitting in the transmission spectra.

Dineen, C.; Förstner, J.; Zakharian, A. R.; Moloney, J. V.; Koch, S. W.

2005-06-01

98

ELECTROMAGNETIC PUMP  

DOEpatents

This patent reiates to electromagnetic pumps for electricity-conducting fluids and, in particular, describes several modifications for a linear conduction type electromagnetic interaction pump. The invention resides in passing the return conductor for the current traversing the fiuid in the duct back through the gap in the iron circuit of the pump. Both the maximum allowable pressure and the efficiency of a linear conduction electromagnetic pump are increased by incorporation of the present invention.

Pulley, O.O.

1954-08-17

99

Ionization energies of W I-LXXIV and critical compilation of spectra and energy levels of Ga I-XXX  

NASA Astrophysics Data System (ADS)

Both tungsten and gallium are important materials for fusion energy research. In this work, a semi-empirical method is used to determine ionization energies (IE) of multiply charged W ions [A.E. Kramida, J. Reader, Ionization Energies of Tungsten Ions: W^2+ through W^71+, At. Data Nucl. Data Tables, 2006, in press]. The method is based on Hartree-Fock calculations of electron binding energies with empirical scale factors. Relative uncertainties vary from 1.7 % for W III^ to 0.015 % for W LXXII. Combined with previously known experimental or theoretical IE values for W I-II and LXXIII-LXXIV, these new semiempirical results allow us to build a complete table of IEs of tungsten in all stages of ionization. For gallium, all available experimental data on wavelengths and energy levels are critically compiled and evaluated [T. Shirai, J. Reader, A.E. Kramida, J. Sugar, Spectral Data for Gallium: Ga I through Ga XXXI, J. Phys. Chem. Ref. Data, 2006, in press]. Such data exist for spectra Ga I-VII, XIII-XXVI, and XXX. For Li-like Ga XXIX through H-like Ga XXXI, theoretical data on energy levels and line wavelengths are compiled. For Ga I-III, XV-XX, XXIII-XXVI, and XXX, radiative transition probabilities are included where available. The ground state configuration and term and a value of IE are included for each ion. This work was supported in part by the Office of Fusion Energy Sciences of the U. S. Department of Energy.

Kramida, Alexander; Reader, Joseph

2006-05-01

100

ELECTROMAGNETISM, OPTICS, ACOUSTICS, HEAT TRANSFER, CLASSICAL MECHANICS, AND FLUID DYNAMICS: Selective Deflection of Polarized Light Via Coherently Driven Four-Level Atoms in a Double-? Configuration  

NASA Astrophysics Data System (ADS)

We study the interaction of a weak probe field, having two circular polarized components, i.e., ?- and ?+ polarization, with an optically dense medium of four-level atoms in a double-? configuration, which is mediated by the electromagnetically induced transparency with a polarized control light with spatially inhomogeneous profile. We analyse the deflection of the polarized probe light and we find that we can selectively determine which circular component will be deflected after the polarized probe light enters the atom medium via adjusting the polarization and detuning of the control field.

Guo, Yu

2010-05-01

101

Electromagnetic environmental criteria for US Army missile systems: EMC (electromagnetic compatibility), EMR (electromagnetic radiation), EMI (electromagnetic interference), EMP (electromagnetic pulse), ESD (electrostatic discharge), and lightning. Final report for period ending October 1986  

Microsoft Academic Search

This report presents the design and test requirements in developing an electromagnetic compatibility missile system. Environmental levels are presented for electromagnetic radiation hazards, electromagnetic radiation operational electrostatic discharge, lightning, and electromagnetic pulse (nuclear). Testing techniques and facility capabilities are presented for research and development testing of missile systems.

M. Kilpatrick; C. D. Ponds

1987-01-01

102

Electromagnetic fasteners  

SciTech Connect

An electromagnetic fastener for manipulating objects in space uses the matic attraction of various metals. An end effector is attached to a robotic manipulating system having an electromagnet such that when current is supplied to the electromagnet, the object is drawn and affixed to the end effector, and when the current is withheld, the object is released. The object to be manipulated includes a multiplicity of ferromagnetic patches at various locations to provide multiple areas for the effector on the manipulator to become affixed to the object. The ferromagnetic patches are sized relative to the object's geometry and mass.

Crane, Randolph W. (Idaho Falls, ID); Marts, Donna J. (Idaho Falls, ID)

1994-01-01

103

Clouds in the atmospheres of extrasolar planets. II. Thermal emission spectra of Earth-like planets influenced by low and high-level clouds  

NASA Astrophysics Data System (ADS)

Aims: We study the impact of multi-layered clouds (low-level water and high-level ice clouds) on the thermal emission spectra of Earth-like planets orbiting different types of stars. Clouds have an important influence on such planetary emission spectra due to their wavelength dependent absorption and scattering properties. We also investigate the influence of clouds on the ability to derive information about planetary surface temperatures from low-resolution spectra. Methods: We use a previously developed parametric cloud model based on observations in the Earth's atmosphere, coupled to a one-dimensional radiative-convective steady state climate model. This model is applied here to study the effect of clouds on the thermal emission spectra of Earth-like extrasolar planets in dependence of the type of central star. Results: The presence of clouds lead in general to a decrease of the planetary IR spectrum associated with the dampening of spectral absorption features such as the 9.6 ?m absorption band of O3 for example. This dampening is not limited to absorption features originating below the cloud layers but was also found for features forming above the clouds. When only single cloud layers are considered, both cloud types exhibit basically the same effects on the spectrum but the underlying physical processes are clearly different. For model scenarios where multi-layered clouds have been considered with coverages which yield mean Earth surface temperatures, the low-level clouds have only a small influence on the thermal emission spectra. In these cases the major differences are caused by high-level ice clouds. The largest effect was found for a planet orbiting the F-type star, where no absorption features can be distinguished in the low-resolution emission spectrum for high cloud coverages. However, for most central stars, planetary atmospheric absorption bands are present even at high cloud coverages. Clouds also affect the derivation of surface temperatures from low-resolution spectra when fitting black-body radiation curves to the spectral shape of the IR emission spectra. With increasing amount of high-level clouds the derived temperatures increasingly under-estimate the real planetary surface temperatures. Consequently, clouds can alter significantly the measured apparent temperature of a planet as well as the detectability of the characteristic spectral signatures in the infrared. Therefore, planets with observationally derived somewhat lower surface temperatures should not be discarded too quickly from the list of potential habitable planets before further investigations on the presence of clouds have been made.

Kitzmann, D.; Patzer, A. B. C.; von Paris, P.; Godolt, M.; Rauer, H.

2011-07-01

104

Biological effects of electromagnetic fields.  

National Technical Information Service (NTIS)

Natural background levels of atmospheric electric and geomagnetic field levels are extremely low. Over the past several decades, however, human beings and other life forms on this planet have been subjected to a dramatically changing electromagnetic milie...

L. E. Anderson

1991-01-01

105

Estimation of the Sea Level Muon Spectra at Different Zenith Angles below 10 TeV Energy  

Microsoft Academic Search

The moderate energy primary cosmic ray nucleon spectrum has been calculated from the direct measurements of Webber et al., Seo et al., and Menn et al. along with the other results surveyed by Swordy. Using these directly measured primary mass composition results all particle primary nucleon energy spectrum has been constructed using superposition model to estimate the energy spectra of

Mala Mitra; N. H. Molla; Pratibha Pal; D. P. Bhattacharyya

2001-01-01

106

Electromagnetic Scattering.  

National Technical Information Service (NTIS)

This report summarizes research results produced by the investigator under support of the Air Force grant. The work has been mainly concerned with the scattering of electromagnetic waves by bounded bodies of small electrical dimensions, but with some cons...

T. B. A. Senior

1983-01-01

107

Electromagnetic Fields  

MedlinePLUS

... off radio-frequency energy (RF), a form of electromagnetic radiation. Scientists need to do more research on this before they can say for sure. NIH: National Institute of Environmental Health Sciences

108

Electromagnetic Hypersensitivity  

Microsoft Academic Search

\\u000a Electromagnetic hypersensitive persons (EHS) attribute their nonspecific health symptoms to environmental electromagnetic\\u000a fields (EMF) of different sources in or outside their homes. In general, causal attribution is not restricted to specific\\u000a EMF frequencies but involves a wide range from extremely low frequencies (ELF) up to radio frequencies (RF) including mobile\\u000a telecommunication microwaves and radar. EHS argue that existing exposure limits

Norbert Leitgeb

109

Information Security due to Electromagnetic Environments  

NASA Astrophysics Data System (ADS)

Generally, active electronic devices emit slightly unintentional electromagnetic noise. From long ago, electromagnetic emission levels have been regulated from the aspect of electromagnetic compatibility (EMC). Also, it has been known the electromagnetic emissions have been generated from the ON/OFF of signals in the device. Recently, it becomes a topic of conversation on the information security that the ON/OFF on a desired signal in the device can be reproduced or guessed by receiving the electromagnetic emission. For an example, a display image on a personal computer (PC) can be reconstructed by receiving and analyzing the electromagnetic emission. In sum, this fact makes known information leakage due to electromagnetic emission. “TEMPEST" that has been known as a code name originated in the U. S. Department of Defense is to prevent the information leakage caused by electromagnetic emissions. This paper reports the brief summary of the information security due to electromagnetic emissions from information technology equipments.

Sekiguchi, Hidenori; Seto, Shinji

110

The Experimental and Calculated Total ?-RAY Spectra and Population of Levels up to 3 Mev of Heavy Nuclei  

NASA Astrophysics Data System (ADS)

Comparison between the experimental and calculated with the parameters [1] spectra demonstrates more or less improvement of their correspondence (up to practical coincidence) for the 114Cd, 158Gd, 166Ho, 168Er, 182Ta, 196Pt, 198Au, and 200Hg compound nuclei and some exceeding of the calculated intensity for 150Sm, 156Gd, 160Tb, 164Dy, 176Lu, and 192Ir at the ?-transition energy E? > 3 - 4 MeV.

Khitrov, V. A.; Sukhovoj, A. M.; Grigoriev, E. P.

2003-06-01

111

Control of spontaneous emission spectra and simulation of multiple spontaneously generated coherence in a four-level atomic system  

NASA Astrophysics Data System (ADS)

We investigate the fluorescence spectrum for a four-level atomic system, three levels of which are coupled with two laser fields in a ladder configuration, and the upper-most level decays to the fourth level via spontaneous emission. The results show that a few interesting phenomena such as spectral-line narrowing, spectral-line enhancement, spectral-line suppression, and spontaneous emission quenching can be realized in our system and can be manipulated via adjusting the proper parameters. It is found that, in the dressed-state picture, this system is equivalent to the system with multiple spontaneously generated coherence studied by Joshi et al. [A. Joshi, W. Yang, M. Xiao, Phys. Lett. A 325 (2004) 30].PACS42.50.Gy32.80.Qk32.50.+dKeywordsSpontaneous emission spectraMultiple spontaneously generated coherenceDressed state pictureReferencesS.Y.ZhuL.M.NarducciM.O.ScullyPhys. Rev. A5219954791S.Y.ZhuR.C.F.ChanC.P.LeePhys. Rev. A521995710S.Y.ZhuH.ChenH.HuangPhys. Rev. Lett.791997205S.JohnT.QuangPhys. Rev. Lett.7819971888P.ZhouS.SwainPhys. Rev. A551997772H.HuangS.Y.ZhuM.S.ZubairyPhys. Rev. A551997744Y.WuPhys. Rev. A612000033803Y.WuP.T.LeungPhys. Rev. A601999630Y.WuX.YangP.T.LeungOpt. Lett.241999345C.H.KeitelP.L.KnightL.M.NarducciM.O.ScullyOpt. Commun.1181995143F.GhafoorS.Y.ZhuM.S.ZubairyPhys. Rev. A622000013811E.PaspalakisC.H.KeitelP.L.KnightPhys. Rev. A5819984868E.PaspalakisP.L.KnightPhys. Rev. Lett.811998293K.T.KapaleM.O.ScullyS.Y.ZhuM.S.ZubairyPhys. Rev. A672003023804M.A.AntónO.G.CalderónF.CarreñoPhys. Rev. A722005023809X.M.HuJ.S.PengJ. Phys. B: At. Mol. Opt. Phys.332000921H.LeeP.PolynkinM.O.ScullyS.Y.ZhuPhys. Rev. A5519974454S.Y.ZhuM.O.ScullyPhys. Rev. Lett.761996388P.R.BermanPhys. Rev. A5819984886P.ZhouS.SwainPhys. Rev. Lett.781997832C.H.KeitelPhys. Rev. Lett.8319991307T.HongC.CramerW.NagourneyE.N.FortsonPhys. Rev. Lett.942005050801F.GhafoorS.QamarM.S.ZubairyPhys. Rev. A652002043819M.A.G.MartinezP.R.HerczfeldC.SamuelsL.M.NarducciC.H.KeitelPhys. Rev. A5519974483G.S.AgarwalPhys. Rev. Lett.671991980A.S.ZibrovM.D.LukinD.E.NikonovL.HollbergM.O.ScullyV.L.VelichanskyH.G.RobinsonPhys. Rev. Lett.7519951499S.E.HarrisPhys. Rev. Lett.6219891033J.Y.GaoC.GuoX.Z.GuoG.X.JinQ.W.WangJ.ZhaoH.Z.ZhangY.JiangD.Z.WangD.M.JiangOpt. Commun.931992323M.O.ScullyM.FleischhauerPhys. Rev. Lett.6919921360M.FleischhauerA.B.MatskoM.O.ScullyPhys. Rev. A622000013808T.HongC.CramerW.NagourneyE.N.FortsonPhys. Rev. Lett.942005050801M.O.ScullyPhys. Rev. Lett.6719911855M.FleischhauerC.H.KeitelM.O.ScullyC.SuB.T.UlrichS.Y.ZhuPhys. Rev. A4619921468C.H.BennettD.P.DivincenzoNature4042000247D.PetrosyanY.P.MalakyanPhys. Rev. A702004023822M.PaternostroM.S.KimP.L.KnightPhys. Rev. A712005022311E.ArimondoE.WolfProgress in Optics1996ElsevierAmsterdam257G.S.AgarwalQuantum Optics1974Springer-VerlagBerlinJ.JavanainenEurophys. Lett.171992407A.FountoulakisA.F.TerzisE.PaspalakisPhys. Rev. A732006033811S.MenonG.S.AgarwalPhys. Rev. A611999013807W.HarshawardhanG.S.AgarwalPhys. Rev. A581998598O.KocharovskayaA.B.MatskoY.RostovtsevPhys. Rev. A652001013803S.MenonG.S.AgarwalPhys. Rev. A5719984014G.X.LiF.L.LiS.Y.ZhuPhys. Rev. A642001013819For early work on this subject, see alsoG.S.AgarwalPhys. Rev. Lett.8420005500J.H.WuA.J.LiY.DingY.C.ZhaoJ.Y.GaoPhys. Rev. A722005023802A.J.LiJ.Y.GaoJ.H.WuL.WangJ. Phys. B: At. Mol. Opt. Phys.3820053815J.H.LiJ.B.LiuA.X.ChenC.C.QiPhys. Rev. A742006033816A.JoshiM.XiaoEur. Phys. J. D352005547A.JoshiW.YangM.XiaoPhys. Lett. A325200430Y.WuX.YangPhys. Rev. A712005053806Y.WuX.YangPhys. Rev. A702004053818Y.WuJ.SaldanaY.ZhuPhys. Rev. A672003013811Y.WuL.WenY.ZhuOpt. Lett.282003631V.WeisskopfE.P.WignerZ. Phys.54193063S.M.BarnettP.M.RadmoreMethods in Theoretical Quantum Optics1997Oxford University PressOxfordWithout loss of generality, we have assumed that the probe field ?p and the coupling field ?c are real in this part.

Li, Jia-Hua; Chen, Ai-Xi; Liu, Ji-Bing; Yang, Xiaoxue

2007-10-01

112

Electromagnetic strong plasma turbulence  

SciTech Connect

The first large-scale simulations of continuously driven, two-dimensional electromagnetic strong plasma turbulence are performed, for electron thermal speeds 0.01c{<=}v{<=}0.57c, by integrating the Zakharov equations for coupled Langmuir and transverse (T) waves near the plasma frequency. Turbulence scalings and wave number spectra are calculated, a transition is found from a mix of trapped and free T eigenstates for v{>=}0.1c to just free eigenstates for v{<=}0.1c, and wave energy densities are observed to undergo slow quasiperiodic oscillations.

Melatos, A.; Jenet, F. A.; Robinson, P. A. [School of Physics, University of Melbourne, Parkville, VIC 3010 (Australia); Department of Physics and Astronomy, University of Texas at Brownsville, Brownsville, Texas 78520 (United States); School of Physics, University of Sydney, Sydney, NSW 2006 (Australia)

2007-02-15

113

Speed of the Electromagnetic Gravitational Wave  

Microsoft Academic Search

With inter-nuclear, gravitational, electromagnetic coupling, and gravitational external body coupling, the electromagnetic waves launched at nucleon level must travel at a speed greater than light speed. This speed is 4.1 x 10 to the 10 meters per second, which is 137 times the normal speed of light. Matter has to be mostly transparent to the gravitational electromagnetic waves emitted; and

Ronald R. Kotas

2000-01-01

114

Electromagnet Lesson  

NSDL National Science Digital Library

This hands-on classroom activity will help students understand the connections between magnets and electricity generation. The learning cycle planner includes an exploration phase with a hands-on activity and a suggested video. The concept development phase suggests showing the film "Who Killed the Electric Car?" The main part of this learning unit is the electromagnet lesson, which is a two day small group activity in which students will create an electromagnet. This document may be downloaded in PDF file format; student worksheets are included.

Orzali, Joe

2011-12-08

115

Electromagnetic ground-based measuring system used for the near real-time hazard level assessment of the earthquake-induced landslides  

NASA Astrophysics Data System (ADS)

In the last decade, the Alpine - Carpathian area was affected by a lot of natural hazard events such as floods and landslides, as a primary consequence of the important climatic changes. The Romanian segment of the Sub-Carpathian chain, these two types of natural events many times got a dramatic character, endangering till now large human communities and also the environment. In the Southern Sub-Carpathian area, the main causes for these phenomena are: the nature of material (flyschoid deposits containing rather soft materials with low mechanic properties), geodynamic context (the existence of Vrancea seismogenic active zone with earthquakes and active tectonics), climate effects leading to huge and irregular precipitation quantity, as well as the anthropic activity. The aim of this paper consists in the implementation of the near-real time electromagnetic ground-based measuring system (EGBMS) and methodology destined to monitor the intermediate Vrancea's earthquakes and associated landslide in a test site placed near by the Provita de Sus locality, Prahova District. Owing to an increasing threat of the landslide in this test site, pre and post seismic landslide models for disaster forecasting are imposed. In this context, the following specific activity stages were accomplished: (i) optimisation of the specific sensor structure in laboratory and field conditions; (ii) experiment and continuous improvement of the EGBMS at the peculiar conditions of the monitored area for pattern recognition; (iii) assessment of the short-term electromagnetic precursory parameters related to both the earthquakes (EQ) occurred at intermediate depth interval, characteristic to the seismic-active Vrancea zone, and the landslides associated, mainly, due to the reactivated faults developed in the Sub-Carpathian area; (iv) elaboration and managing of the datasets available to produce pre and post seismic 2D geophysical models and tomographic images as a first step for the hazard level assessment.

Stanica, D. A.

2012-04-01

116

The electronic spectrum of the fluoroborane free radical. II. Analysis of laser-induced fluorescence and single vibronic level emission spectra  

NASA Astrophysics Data System (ADS)

Subsequent to our spectroscopic detection of the HBX (X=F, Cl, Br) free radicals (S.-G. He, F. X. Sunahori, and D. J. Clouthier, J. Am. Chem. Soc. 127, 10814 (2005)), the electronic spectrum of the A~ 2A''?-X~ 2A' system of the fluoroborane (HBF) radical in the 600-745 nm region has been studied in detail using the pulsed discharge jet technique. The band system involves a linear-bent transition between the two Renner-Teller components of what would be a 2? state at linearity. Using the results of our theoretical study of the ground and excited state vibrational energy levels and 11B-10B isotope shifts (see the companion paper), the vibrational quantum numbers of the bands in the laser-induced fluorescence (LIF) spectra have been assigned. Rotational and vibrational analyses of the LIF and wavelength resolved emission spectra have been carried out, from which the linear excited state and the bent ground state equilibrium configurations have been confirmed. The ground state molecular geometry of HBF has been determined as r0(BH)=1.214(2) A?, r0(BF)=1.303 4(5) A?, and ?=120.7(1)°. Based on high-level ab initio calculations and symmetry considerations, predissociation of the excited state into H(2S)+BF(1?+) on the ground state potential energy surface is identified as the cause of the breaking off of fluorescence in the LIF spectra.

Sunahori, Fumie X.; Clouthier, Dennis J.

2009-04-01

117

Simultaneous electromagnetically induced transparency for two circularly polarized lasers coupled to the same linearly polarized laser in a four-level atomic system in the W scheme  

SciTech Connect

Electromagnetic induced transparency (EIT) can be produced in a four-level atomic system in the W scheme using a linearly polarized optical field for simultaneously slowing down two {sigma}{sup +} and {sigma}{sup -} circularly polarized optical fields. This four-level atomic system can be set up with a |{sup 1}S{sub 0}> ground state and three Zeeman levels of the |{sup 1}P{sub 1}> excited state of any alkali-metal atom placed in a weak magnetic field. We apply our W scheme to ultracold magnesium atoms for neglecting the collisional dephasing. Atomic coherences are reported after solving a density matrix master equation including radiative relaxations from Zeeman states of the |{sup 1}P{sub 1}> multiplet to the |{sup 1}S{sub 0}> ground state. The EIT feature is analyzed using the transit time between the normal dispersive region and the EIT region. The evolution of the EIT feature with the variation of the coupling field is discussed using an intuitive dressed-state representation. We analyze the sensitivity of an EIT feature to pressure broadening of the excited Zeeman states.

Bahrim, Cristian; Nelson, Chris [Department of Physics, Lamar University, P.O. Box 10046, Beaumont, Texas 77710 (United States)

2011-03-15

118

Electromagnetic scattering  

Microsoft Academic Search

This report summarizes research results produced by the investigator under support of the Air Force grant. The work has been mainly concerned with the scattering of electromagnetic waves by bounded bodies of small electrical dimensions, but with some consideration also of acoustic scattering by soft, hard and homogeneous penetrable shapes.

T. B. A. Senior

1983-01-01

119

Electromagnetic Survey  

USGS Multimedia Gallery

USGS hydrologist conducts a broadband electromagnetic survey in New Orleans, Louisiana. The survey was one of several geophysical methods used during USGS applied research on the utility of the multi-channel analysis of surface waves (MASW) seismic method for non-invasive assessment of earthen levee...

2009-05-01

120

Electromagnetic launcher  

Microsoft Academic Search

This paper describes an electromagnetic launcher. It comprises: a stationary superconductive coil situated coaxially in a cylindrical vacuum vessel for providing a magnetic field. The superconductive coil having a central aperture, the vacuum vessel having an axially extending bore passing through the central aperture of the superconducting coil; a resistive coil situated coaxially with the superconductive coil and movable axially

E. T. Laskaris; M. V. K. Chari

1990-01-01

121

Observation of Cd 4d{sup 9}5s{sup 2}5p J=3 autoionizing levels in (e,2e) energy spectra  

SciTech Connect

Cadmium (e,2e) energy spectra have been measured for kinematics corresponding to a momentum transfer of 1 a.u. Two previously unknown cadmium autoinizing levels have been observed. Their energies are in excellent agreement with existing {ital ab initio} structure calculations of the 4d{sup 9}5s{sup 2}5p J=3 levels. One level is easily seen at an ejected-electron direction along the momentum-transfer axis, but is absent for a direction 39{degree} away from this axis. The opposite is true for the other level; it is absent in the former, but present in the latter case. This behavior is in agreement with a calculation that takes into account that the J=3 levels can autoionize into both singlet and triplet 5sEf continua. The intensity of the new levels, relative to the well-known 4d{sup 9}5s{sup 2}5p J=1 levels, agrees well with a plane-wave Born approximation calculation for the J=3 levels. The third 4d{sup 9}5s{sup 2}5p J=3 level is calculated to lie within the broad 4d{sup 9}5s{sup 2}5p {sup 1}P{sub 1} level and cannot be seen in the present experiments. {copyright} {ital 1998} {ital The American Physical Society}

Martin, N.L.S.; Bauman, R.P. [Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506-0055 (United States)] Wilson, M. [Physics Department, Royal Holloway, University of London, Egham, Surrey TW20 0EX (United Kingdom)

1998-06-01

122

On the Energy Level Shifts of Atoms due to the Interaction between the Electron and the Electromagnetic Field  

Microsoft Academic Search

It was ascertained, by the experiment of Lamb and Retherford, that the 2S 12\\/2 and 2P 1\\/2 levels of hydrogen, which are necessarily expected, from Dirac's theory, to coincide, are actually separated by about 1000 M cycles; and it has ever since been attempted by Bethe and many other authors to interprete this as being due to the interaction between

O. Hara; T. Tokano

1949-01-01

123

Electromagnetic Interference and Electromagnetic Compatibility Test Technology  

Microsoft Academic Search

With the extensive application of electronic equipment, issues from electromagnetic compatibility caused by electromagnetic interference will directly affect the normal operation of the system or equipment. In this paper, the electromagnetic interference on the basis of research and analysis the two typical interference source-- the inverter and microwave ovens, to discuss the mechanism and performance of electromagnetic and microwave radiation,

Feng Lv; Hua Zhao; Wenxia Du; Huilong Jin

2010-01-01

124

Nuclear level densities in 208Bi and 209Po from the neutron spectra in the ( p, n) reactions on 208Pb and 209Bi nuclei  

NASA Astrophysics Data System (ADS)

The spectra of neutrons from the ( p, n) reactions on the 208Pb and 209Bi nuclei were measured in the proton-energy range 8-11 MeV. These measurements were performed by using a time-of-flight spectrometer of fast neutrons on the basis of the pulsed tandem accelerator EGP-15 of the Institute of Physics and Power Engineering (Obninsk, Russian Federation). A high resolution and stability of the time-of-flight spectrometermade it possible to identify reliably low-lying discrete levels alongwith the continuum section of the neutron spectra. The measured data were analyzed on the basis of the statistical equilibrium and preequilibrium models of nuclear reactions. The respective calculations were performed by using the precise formalism of Hauser-Feshbach statistical theory together with the generalizedmodel of a superfluid nucleus and the back-shifted Fermi gas model for the nuclear-level density. The nuclear-level densities in 208Bi and 209Po were determined along with their energy dependences and model parameters. Our results are discussed together with available experimental data and recommendations of model systematics.

Zhuravlev, B. V.; Lychagin, A. A.; Titarenko, N. N.; Demenkov, V. G.; Trykova, V. I.

2010-07-01

125

Extension to third-order Coriolis terms of the analysis of ?10, ?7, and ?4 levels of ethylene on the basis of Fourier transform and diode laser spectra  

NASA Astrophysics Data System (ADS)

The ?7, ?10, and ?4 levels of ethylene have been studied based on waveguide laser, Fourier transform, and diode laser spectra in the range from 798 to 1091 cm-1. The absolute calibration of these spectra is better than 0.0002 cm-1. To deal with so many and so accurate experimental data, we have developed in our analysis programs the Watson Hamiltonian up to the sextic centrifugal distortion coefficients and the interaction Hamiltonian up to the third-order Coriolis resonance terms. The molecular parameters of the vibrational ground state have been significantly improved on the basis of more than 4000 GSCD. In the analysis of ?7, ?10, and ?4 levels, we had to introduce the ?12 level, which contributes to the indirect coupling of ?7 and ?4 through strong Coriolis interactions. We obtain a statistical agreement with all experimental data with an estimated standard deviation equal to 0.84. The intrinsic intensity of the ?10 band has been determined to be 16 500 +/- 2500 times lower than the intensity of the ?7 band.

Cauuet, I.; Walrand, J.; Blanquet, G.; Valentin, A.; Henry, L.; Lambeau, Ch.; de Vleeschouwer, M.; Fayt, A.

1990-01-01

126

Modulation of Fourier transform infrared spectra and total sialic acid levels by selenium during 1,2 dimethylhydrazine-induced colon carcinogenesis in rats.  

PubMed

The present study investigated the modulatory potential of selenium supplementation, if any, on Fourier transform infrared (FTIR) spectra in brush border membranes (BBM) of colons and on serum total sialic acid as well as lipid bound sialic acid during 1,2 dimethyl hydrazine (DMH)-induced colorectal carcinogenesis in rats. The FTIR spectra of BBM from the colons of DMH-treated rats revealed a significant increase in the lipid contents but showed a significant decline in the protein contents. Further, decrease in the collagen as well as creatine contents was also noticed in the colons of DMH-treated rats. Supplementation with selenium appreciably restored protein as well as collagen contents and resulted in decreased lipids levels in the colons of DMH-treated rats. Interestingly, a significant increase in the levels of total sialic acid in serum of DMH-treated rats was observed which, however, got moderated significantly upon selenium supplementation. Moreover, no significant changes were observed in the levels of lipid bound sialic acid in all the treated groups as compared to controls. In conclusion, the present study suggested that supplementation of selenium act as a chemopreventive agent and delays considerably the process of colon carcinogenesis. PMID:23368918

Ghadi, Fereshteh Ezzati; Malhotra, Anshoo; Ghara, Abdollah Ramzani; Dhawan, D K

2013-01-01

127

Response of a two-level system to a single resonant laser pulse and nonresonant electromagnetic standing waves  

NASA Astrophysics Data System (ADS)

This is a study of the responses of a two-level system to a sequence of short, spatially inhomogeneous laser pulses, one of which is resonant plus one or two which are nonresonant. It is found that at certain times the system responds, and that the conditions for formation of the responses depend on the region excited by the inhomogeneously broadened line of the resonant laser pulse and the parameters of the nonresonant pulses. It is proposed that responses of this type be used for determining the transverse relaxation time of the system without delay lines for the laser pulses.

Garnaeva, G. I.; Nefediev, L. A.; Hakimzyanova, E. I.

2013-09-01

128

Electromagnetic field structure and normal mode coupling in photonic crystal nanocavities.  

PubMed

The electromagnetic field of a high-quality photonic crystal nanocavity is computed using the finite difference time domain method. It is shown that a separatrix occurs in the local energy flux discriminating between predominantly near and far field components. Placing a two-level atom into the cavity leads to characteristic field modifications and normal-mode splitting in the transmission spectra. PMID:19498486

Dineen, C; Förstner, J; Zakharian, A; Moloney, J; Koch, S

2005-06-27

129

LETTER TO THE EDITOR: Energy levels of 4f3 in the Nd3+ free ion from emission spectra  

NASA Astrophysics Data System (ADS)

The emission spectrum of neodymium produced by vacuum spark sources was observed in the vacuum ultraviolet on two normal-incidence spectrographs. In an initial result, more than 550 lines have been identified as transitions from 85 4f25d levels to 37 levels of the 4f3 ground configuration in the free ion Nd3+. The levels 4f34F3/2 and 4I11/2, responsible for the well-known 1064 nm laser line, have respective positions of 11 698.57 ±0.1 cm-1 and 1897.07 ±0.1 cm-1 above the ground level 4I9/2. The newly found levels of 4f3 constitute the first isolated 4fN configuration (N > 2) and therefore enable checks of effective parameters that represent far configuration interaction. Slater parameters Fk(4f, 4f) derived from Nd3+:LaCl3 are 3% to 5% smaller than in the free ion.

Wyart, Jean-François; Meftah, Ali; Bachelier, Annik; Sinzelle, Jocelyne; Tchang-Brillet, Wan-Ü. Lydia; Champion, Norbert; Spector, Nissan; Sugar, Jack

2006-03-01

130

Electromagnetic Spectrum from QGP Fluid  

Microsoft Academic Search

We calculate thermal photon and electron pairdistribution from hot QCD matter produced in high energy heavy-ion collisions, based on a hydrodynamical model which is so tuned as to reproduce the recent experimental data at CERN SPS, and compare these electromagnetic spectra with experimental data given by CERN WA80 and CERES. We investigate mainly the effects of the off-shell properties of

Tetsufumi Hirano; Shin Muroya; Mikio Namiki

1997-01-01

131

Evidence for replicate 5p core levels in photoelectron spectra of Eu metal due to nonconstant kinetic-energy resonant Auger decay  

SciTech Connect

Satellites on the low-binding-energy side of core-level photoelectron emission due to extra 4f screening are a well-known feature in the x-ray photoelectron spectra of valence fluctuation materials and rare-earth metals. A notable exception is Eu metal, where up to now no low-binding-energy satellite has been observed. In this paper we show that in Eu metal the 4d-4f resonance can decay via a resonant Auger decay, which is not a constant kinetic-energy feature due to a rapid change of the strength of 4f screening with excitation energy, establishing a low-binding-energy replica of the 5p core-level photoelectron emission. (c) 1999 The American Physical Society.

Haffner, S. [Department of Physics and Ames Laboratory, U. S. Department of Energy, Iowa State University, Ames, Iowa 50011 (United States); Olson, C. G. [Department of Physics and Ames Laboratory, U. S. Department of Energy, Iowa State University, Ames, Iowa 50011 (United States); Lynch, D. W. [Department of Physics and Ames Laboratory, U. S. Department of Energy, Iowa State University, Ames, Iowa 50011 (United States)

1999-12-15

132

IUPAC critical evaluation of the rotational-vibrational spectra of water vapor, Part III: Energy levels and transition wavenumbers for H216O  

NASA Astrophysics Data System (ADS)

This is the third of a series of articles reporting critically evaluated rotational-vibrational line positions, transition intensities, and energy levels, with associated critically reviewed labels and uncertainties, for all the main isotopologues of water. This paper presents experimental line positions, experimental-quality energy levels, and validated labels for rotational-vibrational transitions of the most abundant isotopologue of water, H216O. The latest version of the MARVEL (Measured Active Rotational-Vibrational Energy Levels) line-inversion procedure is used to determine the rovibrational energy levels of the electronic ground state of H216O from experimentally measured lines, together with their self-consistent uncertainties, for the spectral region up to the first dissociation limit. The spectroscopic network of H216O containstwo components, an ortho (o) and a para (p) one. For o-H216O and p-H216O, experimentally measured, assigned, and labeled transitions were analyzed from more than 100 sources. The measured lines come from one-photon spectra recorded at room temperature in absorption, from hot samples with temperatures up to 3000 K recorded in emission, and from multiresonance excitation spectra which sample levels up to dissociation. The total number of transitions considered is 184 667 of which 182 156 are validated: 68 027 between para states and 114 129 ortho ones. These transitions give rise to 18 486 validated energy levels, of which 10 446 and 8040 belong to o-H216O and p-H216O, respectively. The energy levels, including their labeling with approximate normal-mode and rigid-rotor quantum numbers, have been checked against ones determined from accurate variational nuclear motion computations employing exact kinetic energy operators as well as against previous compilations of energy levels. The extensive list of MARVEL lines and levels obtained are deposited in the supplementary data of this paper, as well as in a distributed information system applied to water, W@DIS, where they can easily be retrieved.

Tennyson, Jonathan; Bernath, Peter F.; Brown, Linda R.; Campargue, Alain; Császár, Attila G.; Daumont, Ludovic; Gamache, Robert R.; Hodges, Joseph T.; Naumenko, Olga V.; Polyansky, Oleg L.; Rothman, Laurence S.; Vandaele, Ann Carine; Zobov, Nikolai F.; Al Derzi, Afaf R.; Fábri, Csaba; Fazliev, Alexander Z.; Furtenbacher, Tibor; Gordon, Iouli E.; Lodi, Lorenzo; Mizus, Irina I.

2013-03-01

133

Electromagnetic microactuators  

NASA Astrophysics Data System (ADS)

High precision microactuators have become key elements for many applications of MEMS, for example for positioning and handling systems as well as for microfluidic devices. Electromagnetic microactuators exhibit considerable benefits such as high forces, large deflections, low input impedances and thus, the involvement of only low voltages. Most of the magnetic microactuators developed so far are based on the variable reluctance principle and use soft magnetic materials. Since the driving force of such actuators is proportional to their volume, they require structures with rather great heights and aspect ratios. Therefore, the development of new photo resists, which allow UV exposure of thick layers of resist, has been essential for the advancement of variable reluctance microactuators. On the other hand, hard magnetic materials have the potential for larger forces and larger deflections. Accordingly, polymer magnets, in which micro particles of hard magnetic material are suspended in a polymer matrix, have been used to fabricate permanent magnet microactuators. In this paper we give an overview of sophisticated electromagnetic microactuators which have been developed in our laboratory in the framework of the Collaborative Research Center "Design and Manufacturing of Active Microsystems". In particular, concept, fabrication and test of variable reluctance micro stepper motors, of permanent magnet synchronous micromotors and of microactuators based on the Lorentz force principle will be described. Special emphasis will be given to applications in lab-on-chip systems.

Büttgenbach, S.; Al-Halhouli, A. T.; Feldmann, M.; Seidemann, V.; Waldschik, A.

2013-05-01

134

Electromagnetic calorimetry  

NASA Astrophysics Data System (ADS)

Electromagnetic calorimetry forms a key element of almost all current high energy particle physics detectors and has widespread application in related experimental fields such as nuclear physics and astro-particle physics. It will play a particularly important role in the latest generation of experiments at the CERN Large Hadron Collider (LHC), where it is expected that high energy electrons and photons will provide some of the clearest signatures for new discoveries. This article introduces the basic concepts underlying electromagnetic calorimetry and illustrates how these principles have been applied in recent and current detector designs, explaining the connection between technical choices and specific physics goals. Designs are described in sufficient detail to demonstrate the compromises that have to be made in achieving optimum performance within practical constraints. The main emphasis is on the LHC experiments, which provide outstanding examples of the state-of-the-art. Selected examples from other domains, such as nuclear physics and neutrino experiments are also considered and particular attention is given to calorimeter design studies for the proposed International Linear Collider (ILC) where the concept of Particle Flow Analysis is being used as a guiding influence in the overall detector optimization.

Brown, R. M.; Cockerill, D. J. A.

2012-02-01

135

Electromagnetic Topology: Characterization of Internal Electromagnetic Coupling.  

National Technical Information Service (NTIS)

The main principles are presented of a method dealing with the resolution of electromagnetic internal problems: Electromagnetic Topology. A very interesting way is to generalize the multiconductor transmission line network theory to the basic equation of ...

J. P. Parmantier J. P. Aparicio F. Faure

1991-01-01

136

DISPLACEMENT SPECTRA FOR SEISMIC DESIGN  

Microsoft Academic Search

Displacement-based seismic design and assessment of structures require the reliable definition of displacement spectra for a wide range of periods and damping levels. The displacement spectra derived from acceleration spectra in existing seismic codes do not provide a suitable answer and there are no existing frequency-dependent attenuation relationships derived specifically for this purpose. Using a carefully processed dataset of European

JULIAN J. BOMMER; AMR S. ELNASHAI

1999-01-01

137

Electromagnetic field cancer scares.  

PubMed

The internal electric current or power levels that a human is likely to encounter in a typical electromagnetic field environment are calculated. At 60 Hz, a reasonable value for maximum permissible exposure is an internal current density of 1 microA cm(-2). At this frequency, a 600 V m(-1) electric field results in a current density of 0.0002 microA cm(-2), while a 200 microT magnetic field results in 0.6 microA cm(-2). This should be compared with an action potential, which is associated with a current density of 800 microA cm(-2). The ANSI/IEEE C95.1-1991 standards, whose frequency range is 3 kHz to 300 GHz, are examined. Epidemiological studies are briefly considered. The conclusion is that it is highly unlikely that there is a link between electromagnetic fields and cancer. PMID:9228165

Deutsch, S; Wilkening, G M

1997-08-01

138

On the electromagnetic fields induced by oceanic internal waves  

Microsoft Academic Search

Natural electromagnetic fields in the oceans are induced by both external ionospheric and magnetospheric electric current systems flowing far above the earth and by the dynamo interaction of ocean currents with the earth's magnetic field. In the present investigation, theoretical spectra of the electromagnetic fields and their gradients generated by ambient internal waves are obtained by combining the poloidal and

A. D. Chave

1984-01-01

139

Electromagnetic topology: Characterization of internal electromagnetic coupling  

Microsoft Academic Search

The main principles are presented of a method dealing with the resolution of electromagnetic internal problems: Electromagnetic Topology. A very interesting way is to generalize the multiconductor transmission line network theory to the basic equation of the Electromagnetic Topology: the BLT equation. This generalization is illustrated by the treatment of an aperture as a four port junction. Analytical and experimental

J. P. Parmantier; J. P. Aparicio; F. Faure

1991-01-01

140

Electromagnetic topology - Characterization of internal electromagnetic coupling  

Microsoft Academic Search

This paper presents the main principles of a method dealing with the resolution of electromagnetic internal problems: electromagnetic topology. A very interesting way is to generalize the multiconductor transmission line network theory to the basic equation of electromagnetic topology. This generalization is illustrated by the treatment of an aperture as a four port junction. Analytical and experimental derivations of the

J. P. Parmantier; J. P. Aparicio; F. Faure

1991-01-01

141

ELECTROMAGNETISM, OPTICS, ACOUSTICS, HEAT TRANSFER, CLASSICAL MECHANICS, AND FLUID DYNAMICS: Local Control of Two-Photon Absorption in a Six-Level Atomic System by Using a Coherent Perturbation Field  

NASA Astrophysics Data System (ADS)

If a coherent perturbation field is used to couple the excited level of the coupling transition in the five-level K-type atom with another higher excited level, the two-photon electromagnetically induced transparency can be locally modulated by altering the parameters of the additional perturbation field. With different detunings of the coherent perturbation field, the absorption peak or transparency window with sharp and high-contrast spectral feature can be generated in the two-photon absorption spectrum. The physical interpretation of these phenomena is given in terms of the dressed states.

Jia, Wen-Zhi; Wang, Shun-Jin

2009-11-01

142

Transient electromagnetic interference in substations  

Microsoft Academic Search

Electromagnetic interference levels on sensitive electronic equipment are quantified experimentally and theoretically in air and gas insulated substations of different voltages. Measurement techniques for recording interference voltages and currents and electric and magnetic fields are reviewed and actual interference data are summarized. Conducted and radiated interference coupling mechanisms and levels in substation control wiring are described using both measurement results

C. M. Wiggins; D. E. Thomas; F. S. Nickel; T. M. Salas; S. E. Wright

1994-01-01

143

Dynamics of fundamental electromagnetic emission via beam-driven Langmuir waves  

SciTech Connect

The nonlinear process of electromagnetic Langmuir decay, which leads to radio emission near the plasma frequency, is studied for situations in which Langmuir waves are directly driven by an electron beam and indirectly generated via electrostatic Langmuir decays. The electromagnetic Langmuir decay is stimulated by the presence of ion-acoustic waves. An approximate method is devised for studying this emission process with axial symmetry (along the direction of beam propagation) in three spatial dimensions, based upon the Langmuir and ion-acoustic wave dynamics in one spatial dimension. Numerical studies of the fundamental electromagnetic emission starting from electron dynamics are then carried out via quasilinear theory, and the results are explored for illustrative parameters. The evolution of the fundamental transverse waves shows the combined effects of local emission and propagation away from the source. At a given location, the emission rate shows a series of peaks associated with successive electromagnetic decays of the Langmuir waves, which are either driven by the beam or produced by successive electrostatic decays. The emission rate for a given electromagnetic decay decreases with time, following an initial increase. In addition, the emission rate for a specific electromagnetic decay shows approximate dipolar form, consistent with previous analytical work. Consequently, the fundamental transverse waves emitted locally propagate approximately symmetrically in both the forward and the backward directions. Variation of the background electron to ion temperature ratio, beam injection parameters, and angular widths of the Langmuir and ion-acoustic spectra are found to affect the emission rate and, hence, the fundamental transverse wave levels. Furthermore detailed studies show that the wave numbers of the maximum emission rates are also in good agreement with an approximate prediction for simple model Langmuir and ion-acoustic spectra.

Li, B.; Willes, A.J.; Robinson, P.A.; Cairns, I.H. [School of Physics, University of Sydney, New South Wales 2006 (Australia)

2005-05-15

144

Out-of-plane (e,2e) angular distributions and energy spectra of helium L = 0,1,2 autoionizing levels  

NASA Astrophysics Data System (ADS)

Angular distribution and spectral (e,2e) measurements are reported for the helium autoionizing levels (2s2)1S, (2p2)1D, and (2s2p)1P. A special out-of-plane geometry is used where the ejected electrons are emitted in a plane perpendicular to the scattered electron direction. The kinematics are chosen so that this plane contains the momentum-transfer direction. While the recoil peak almost vanishes in the angular distribution for direct ionization, it remains significant for the autoionizing levels and exhibits a characteristic shape for each orbital angular momentum L=0,1,2. A second-order model in the projectile-target interaction correctly reproduces the observed magnitudes of the recoil peaks, but is a factor of 2 too large in the central out-of-plane region. Observed (e,2e) energy spectra for the three resonances over the full angular range are well reproduced by the second-order calculation. Calculations using a first-order model fail to reproduce both the magnitudes of the recoil peaks and the spectral line profiles.

Deharak, B. A.; Bartschat, K.; Martin, N. L. S.

2010-12-01

145

Out-of-plane (e,2e) angular distributions and energy spectra of helium L = 0,1,2 autoionizing levels  

SciTech Connect

Angular distribution and spectral (e,2e) measurements are reported for the helium autoionizing levels (2s{sup 2}){sup 1}S, (2p{sup 2}){sup 1}D, and (2s2p){sup 1}P. A special out-of-plane geometry is used where the ejected electrons are emitted in a plane perpendicular to the scattered electron direction. The kinematics are chosen so that this plane contains the momentum-transfer direction. While the recoil peak almost vanishes in the angular distribution for direct ionization, it remains significant for the autoionizing levels and exhibits a characteristic shape for each orbital angular momentum L=0,1,2. A second-order model in the projectile-target interaction correctly reproduces the observed magnitudes of the recoil peaks, but is a factor of 2 too large in the central out-of-plane region. Observed (e,2e) energy spectra for the three resonances over the full angular range are well reproduced by the second-order calculation. Calculations using a first-order model fail to reproduce both the magnitudes of the recoil peaks and the spectral line profiles.

Harak, B. A. de [Physics Department, Illinois Wesleyan University, P.O. Box 2900, Bloomington, Illinois 61702-2900 (United States); Bartschat, K. [Department of Physics and Astronomy, Drake University, Des Moines, Iowa 50311 (United States); Martin, N. L. S. [Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506-0055 (United States)

2010-12-15

146

Atomic Spectra  

NSDL National Science Digital Library

This page from Hyperphysics contains images depicting the light emitted by several elements and their respective spectra. The page also provides a description of how the size of a holographic image scales with the wavelength of the light used to observe it.

Nave, Carl R.

2010-03-12

147

Atomic Spectra  

NSDL National Science Digital Library

In this Flash animation the user can view the atomic emission spectra (400-700nm) of eight different elements. A dragable marker allows the user to approximate the wavelength of the various spectral lines. The effect of resolution can be examined in the sodium spectrum in the region 550-600nm.

148

Thermodynamic analysis of spectra  

SciTech Connect

Although random matrix theory had its initial application to neutron resonances, there is a relative scarcity of suitable nuclear data. The primary reason for this is the sensitivity of the standard measures used to evaluate spectra--the spectra must be essential pure (no state with a different symmetry) and complete (no states missing). Additional measures that are less sensitive to these experimental limitations are of significant value. The standard measure for long range order is the {delta}{sub 3} statistic. In the original paper that introduced this statistic, Dyson and Mehta also attempted to evaluate spectra with thermodynamic variables obtained from the circular orthogonal ensemble. We consider the thermodynamic 'internal energy' and evaluate its sensitivity to experimental limitations such as missing and spurious levels. Monte Carlo simulations suggest that the internal energy is less sensitive to mistakes than is {delta}{sub 3}, and thus the internal energy can serve as a addition to the tool kit for evaluating experimental spectra.

Mitchell, G. E. [North Carolina State University, Raleigh, NC 27695 and Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Shriner, J. F. Jr. [Tennessee Technological University, Cookeville, TN 38505 (United States)

2008-04-04

149

Electromagnetic field spectral evaluation problems in exposure assessment.  

PubMed

Electromagnetic fields have become an omnipresent factor in our daily environment. It has become common that the exposure situations are characterised by a cocktail of spectral contributions from different sources, while exposures to single frequencies are rare. Thirty-two different types of drilling machines were analysed. Even similar devices exhibited large variations of emission levels up to two orders of magnitudes. It was found that emissions are not negligible and could be close or even above reference levels. Already single spectral peaks of magnetic emissions may considerably exceed reference levels, and excess can reach even the 90-fold when evaluating the entire spectrum. It is shown that approaches to assess complex frequency spectra as proposed by the International Commission on Non-Ionising Radiation Protection or defined in compliance standards issued by CENELEC or IEC lead to contradictory conclusions on conformity or non-conformity. There is an urgent need to clarify this discrepancy. PMID:17494982

Leitgeb, N; Cech, R; Schröttner, J

2007-05-10

150

Electromagnetically induced conical emission  

NASA Astrophysics Data System (ADS)

We describe theoretically a scheme for observing conical emission, a transverse nonlinear optical effect, in an atomic vapor with all excitation fields below the saturation level of the involved atomic transitions. The scheme relies on the giant Kerr nonlinearities possible under electromagnetically induced transparency to introduce a radially varying phase shift to a weak probe field by a weak signal field. The probe’s far-field diffraction pattern shows multiple concentric rings around the probe beam’s axis, characteristic of conical emission.

Becerra-Castro, E. M.; de Araujo, Luís E. E.

2010-12-01

151

Dependence of the resonant electromagnetic background frequencies in the frequency range of the alfven ionospheric resonator on the level of the solar activity  

NASA Astrophysics Data System (ADS)

In the work, variations of the resonant electromagnetic background frequencies in the frequency range of the ionospheric Alfven resonator are investigated. An algorithm of automatic determination of the resonant characteristics of registered signals is presented. It is established that the variations of the resonant frequencies are determined on 75% by their seasonal changes; the relative contribution of the 11-year period caused by the solar activity does not exceed 15%.

Kolesnik, A. G.; Kolesnik, S. A.; Kolmakov, A. A.; Chernyshev, I. V.

2011-02-01

152

Fluorescence Spectra  

NSDL National Science Digital Library

This experiment uses the Tracker video analysis and modeling tool to explore the phenomenon of fluorescence and its application in fluorescent lamps. For each of five different visible spectra, students (a) observe the spectrum directly, (b) measure its brightness versus wavelength in Tracker, and (c) answer both qualitative and quantitative questions about it. The spectra include a fluorescent dye with laser and UV illumination, a mercury lamp and two fluorescent lamps, all with red and green laser spots added for easy calibration. For more information, see the AAPT presentation. The zip file includes the lab instructions, spectrum images and Tracker data files. This requires Tracker version 4.62 or higher. Tracker installers are available for Windows, Mac and Linux from ComPADRE or the Tracker web site (http://www.cabrillo.edu/~dbrown/tracker/).

Brown, Douglas

2012-01-17

153

Changes induced in electrical properties and deep level spectra of p-AlGaN films by treatment in hydrogen plasma and by proton implantation  

NASA Astrophysics Data System (ADS)

The influence of hydrogen plasma treatment (250 °C, 0.5 h) and of proton implantation (proton energy of 200 keV, doses between 1012 and 1015 cm-2) on electrical properties of p-AlGaN films were studied. Hydrogen plasma treatment leads to substantial (more than an order of magnitude) decrease of the hole concentration in the surface layer. The dominant deep traps observed in current deep level transient spectroscopy were the Mg-related hole traps with activation energy of 0.17 eV and 0.19 eV. The concentration of both traps was strongly decreased after the hydrogen plasma treatment. At the same time the MCL intensity in the bandedge wavelength region was greatly increased. The results are explained by partial hydrogen passivation of Mg acceptors and of deep centers responsible for non-radiative recombination. Proton implantation was found to lead to a strong decrease of hole concentration, to a decrease in the intensity of the bandedge MCL signal and to a strong suppression of the signal from the hole traps with activation energy of 0.17 eV-0.19 eV. However, no new prominent deep centers were detected in deep level spectra after the implantation. It is suggested that the main centers responsible for the increased compensation of the layers are located in the upper part of the bandgap. Possible interplay between the hydrogen passivation of deep defects and introduction of new defects due to radiation and possibly due to hydrogen interaction with primary radiation defects will be discussed.

Polyakov, A. Y.; Smirnov, N. B.; Govorkov, A. V.; Khanna, Rohit; Pearton, S. J.

2005-05-01

154

Electromagnetic anomaly before earthquakes measured by electromagnetic experiments  

NASA Astrophysics Data System (ADS)

Three experiments are carried out for earthquake monitoring using electromagnetic (EM) methods in recent years. Some earthquakes occurred in chance of the measurement time period for each experiment and the anomalies were recorded before the shocks. The observation at a site 20 km away from the epicenter of Zhangbei M S6.2 earthquake in 1998 shows that the apparent resistivity decreases in the strike direction before and/or during the earthquake and the resistivity increases in the decline direction. This anomalous variation in apparent resistivity accounts for about 20%. The apparent resistivities at a site in the epicentral area decrease in the strike and decline directions before and/or during the earthquake and increase after shocks. The experiments using artificial electromagnetic signals with super low frequency carried out in 1999 show that the resolution and stability of electric and magnetic spectra are improved. The spectra of electric and magnetic fields and apparent resistivity at the Baodi station began to anomalously change two days before the Qian’an earthquake with 120 km distant to the station. The anomalous variation of electric and magnetic spectra is about twice as great as normal variation and the apparent resistivity changes by about 20%. The measurements in active seismic area of Yunnan province in the year 2005 indicate that the electric and magnetic spectra anomalously change by one order before the Taoyuan earthquake about 100 km away from the observatories. But the measurements at the sites in Beijing area 2 000 km away from the epicenter do not show any anomaly.

Zhao, Guoze; Zhan, Yan; Wang, Lifeng; Wang, Jijun; Tang, Ji; Xiao, Qibin; Chen, Xiaobin

2009-08-01

155

Electromagnetic propulsion for spacecraft  

NASA Astrophysics Data System (ADS)

Three electromagnetic propulsion technologies, solid propellant pulsed plasma thrusters (PPT), magnetoplasmadynamic (MPD) thrusters, and pulsed inductive thrusters (PIT), were developed for application to auxiliary and primary spacecraft propulsion. Both the PPT and MPD thrusters were flown in space, though only PPT's were used on operational satellites. The performance of operational PPT's is quite poor, providing only approximately 8 percent efficiency at approximately 1000 s specific impulse. However, laboratory PPT's yielding 34 percent efficiency at 2000 s specific impulse were extensively tested, and peak performance levels of 53 percent efficiency at 5170 s specific impulse were demonstrated. MPD thrusters were flown as experiments on the Japanese MS-T4 spacecraft and the Space Shuttle and were qualified for a flight in 1994. The flight MPD thrusters were pulsed, with a peak performance of 22 percent efficiency at 2500 s specific impulse using ammonia propellant. Laboratory MPD thrusters were demonstrated with up to 70 percent efficiency and 700 s specific impulse using lithium propellant. While the PIT thruster has never been flown, recent performance measurements using ammonia and hydrazine propellants are extremely encouraging, reaching 50 percent efficiency for specific impulses between 4000 to 8000 s. The fundamental operating principles, performance measurements, and system level design for the three types of electromagnetic thrusters are reviewed, and available data on flight tests are discussed for the PPT and MPD thrusters.

Myers, Roger M.

1993-09-01

156

Electromagnetic Pulse Rotary Seal.  

National Technical Information Service (NTIS)

An rotary seal for protection against electromagnetic interference and electromagnetic pulses is disclosed. An electrically conductive resilient bellows surrounds a shaft extending through an opening in an enclosure. The bellows is attached at one end to ...

C. W. Neher

1987-01-01

157

The Electromagnetic Spectrum  

NSDL National Science Digital Library

This web site contains materials about all parts of the electromagnetic spectrum. It describes each space telescope that NASA has launched as well as its observing range in the electromagnetic spectrum.

Astrophysics, Laboratory F.

2004-11-17

158

The Electromagnetic Spectrum: FRONTLINE  

NSDL National Science Digital Library

This video segment adapted from FRONTLINE introduces the electromagnetic spectrum and explains how the various types of electromagnetic waves are distinguished by the amount of energy each wave carries.

Foundation, Wgbh E.

2004-02-20

159

Skyglow effects in UV and visible spectra: radiative fluxes.  

PubMed

Several studies have tried to understand the mechanisms and effects of radiative transfer under different night-sky conditions. However, most of these studies are limited to the various effects of visible spectra. Nevertheless, the invisible parts of the electromagnetic spectrum can pose a more profound threat to nature. One visible threat is from what is popularly termed skyglow. Such skyglow is caused by injudiciously situated or designed artificial night lighting systems which degrade desired sky viewing. Therefore, since lamp emissions are not limited to visible electromagnetic spectra, it is necessary to consider the complete spectrum of such lamps in order to understand the physical behaviour of diffuse radiation at terrain level. In this paper, the downward diffuse radiative flux is computed in a two-stream approximation and obtained ultraviolet spectral radiative fluxes are inter-related with luminous fluxes. Such a method then permits an estimate of ultraviolet radiation if the traditionally measured illuminance on a horizontal plane is available. The utility of such a comparison of two spectral bands is shown, using the different lamp types employed in street lighting. The data demonstrate that it is insufficient to specify lamp type and its visible flux production independently of each other. Also the UV emissions have to be treated by modellers and environmental scientists because some light sources can be fairly important pollutants in the near ultraviolet. Such light sources can affect both the living organisms and ambient environment. PMID:23792881

Kocifaj, Miroslav; Solano Lamphar, H A

2013-06-21

160

Electromagnetic Interference (Emi)  

Microsoft Academic Search

\\u000a Electric and magnetic signals originating outside of a defibrillator may affect its operation, a phenomenon known as electromagnetic\\u000a interference (EMI). EMI usually refers to interference from environmental electromagnetic instrumentation and should be distinguished\\u000a from other sources of electromagnetic noise causing ICD malfunction (Table 1). Signals most likely to penetrate and affect\\u000a pacemakers and ICDs are electromagnetic waves or signals at

Mike Hardage; Philip D. Henry

161

Electromagnetic Interference with Hall Thruster Operation  

NASA Astrophysics Data System (ADS)

The report is concerned with the experience of radio frequency underground testing of Hall plasma thrusters. Both previously published and new experimental data on the generation of microwave oscillations in Hall thrusters are analyzed. The spectra of microwave oscillations and electromagnetic radiation with electron dynamic are determined. The results of ground radio engineering tests on the thruster modules of a combined propulsion unit for Yamal-100 spacecraft are presented and a pulsed electromagnetic radiation component was detected. The experimental data on the amplification of microwave fields by the plasma thruster are presented. The conditions of anomalous microwave fields-plasma interaction are established.

Kirdyashev, K.

2004-10-01

162

Composite electromagnetic pulse threat  

Microsoft Academic Search

A new electromagnetic pulse threat based on a composite ambient field defined by a combination of lightning, NEMP (nuclear electromagnetic pulse) and microwave threats is discussed. The composite electromagnetic pulse threat has been used to harden a military helicopter. The hardening to a composite threat resulted in the development of simplified hardening verification procedures. It also provided an economical advantage

A. S. Podgorski

1990-01-01

163

Composite electromagnetic pulse threat  

Microsoft Academic Search

A new electromagnetic pulse threat that is based on a composite ambient field defined by a combination of lightning, NEMP (nuclear electromagnetic pulse) and microwave threats is discussed. The composite electromagnetic pulse threat has been used to harden a military helicopter. The hardening to a composite threat resulted in the development of simplified hardening verification procedures. It also provided an

Andrew S. Podgorski

1990-01-01

164

Electromagnetic field litigation  

SciTech Connect

Scientific research has been unable to resolve satisfactorily the question whether potential biological effects, especially carcinogenicity, may be associated with exposure of humans to the electromagnetic fields (EMFs) from high-voltage transmission lines. It may be years before the necessary human, laboratory, and basic research produce the evidence needed for professional consensus on this environmental issue. But as the scientific debate and human exposure continue, public concern is being expressed in administrative and judicial proceedings. During the past decade, the public perceptions of risk from nonionizing radiation of electromagnetic fields has been a factor introduced in local, state, and federal hearings; administrative proceedings; and court litigation. The focus of this review is to highlight public concern by examining the pattern of litigation in which bioeffects were alleged to be associated with transmission (power) lines. In this regard, the courts have split widely on the probative value and admissibility of scientifically based testimony to support compensation claims. Condemnation cases involving appellate court review, selected trial-level cases, and the emergence of tort claims are described. The use of tort claims imposes a substantial burden of proof on the plaintiff to demonstrate a cause-effect relationship between EMF exposure and disease. Finally, risk communication and public policy are discussed.

Hamilton, C.B. (Univ. of Tennessee, Knoxville, TN (United States)); Easterly, C.E. (Oak Ridge National Lab., TN (United States). Health and Safety Research Division)

1993-01-01

165

Optical spectra, energy levels and crystal-field analysis of Sm3 in Na3[Sm(oxydiacetate)3] · 2NaClO4 · 6H2O  

Microsoft Academic Search

Locations and assignments of 144 crystal-field energy levels are reported for Sm3+ in the trigonal Na3[Sm(oxydiacetate)3] · 2NaClO4 · 6H2O system. These energy levels span the 0-36 000 cm-1 energy region, and they were located and assigned from optical emission spectra and from axial and orthoaxial (sigma- and pi-polarized) absorption measurements on single crystals. The principal SL parentages of the

P. Stanley May; Michael F. Reid; F. S. Richardson

1987-01-01

166

Electromagnetic Radiation: On Trial  

NSDL National Science Digital Library

This activity introduces students to the properties of electromagnetic radiation in a variety of ways. For example, they put the different types of the electromagnetic radiation on trial, selecting the judge, prosecutor, defense counsel, and jury, and learning about electromagnetic energy by arguing the pros and cons of each wavelength. During this activity, students are introduced to the general properties of electromagnetic waves, learn to analyze the relation between the specific properties of waves and their position in the electromagnetic spectrum, and discuss methods used to detect and analyze different waves. Students also learn about scientists whose work contributed to our understanding of electromagnetic energy. Students are encouraged to use an electronic bulletin board to communicate with each other, posting insights, ideas, evidence and questions on electromagnetic energy.

2007-05-16

167

Wavelet Denoising of Infrared Spectra  

Microsoft Academic Search

The application of wavelet denoising to infrared spectra was investigated. Six different wavelet denoising methods (SURE, VISU, HYBRID, MINMAX, MAD and WAVELET PACKETS) were applied to pure infrared spectra with various added levels of homo- and heteroscedastic noise. The performances of the wavelet denoising methods were compared with the standard Fourier and moving mean filtering in terms of root mean

Bjørn K. Alsberg; Andrew M. Woodward; Michael K. Winson; Jem Rowland; Douglas B. Kell

1997-01-01

168

Quantitative and qualitative characterization of 1H NMR spectra of colon tumors, normal mucosa and their perchloric acid extracts: decreased levels of myo-inositol in tumours can be detected in intact biopsies.  

PubMed

Sixteen colonic tumours and 10 normal mucosa biopsies have been examined by 1H NMR spectroscopy at 9.4 T. A complete characterization and quantification of the aliphatic region of PCA extract spectra and the analysis of the two-dimensional COSY spectra of five pairs of intact biopsies (tumor and control mucosa) has been carried out. The analysis of the PCA extracts demonstrated a significant increase in the concentration of the endogenous compounds: lactate, glutamate, aspartate, taurine, spermine, glutathione and glycerophosphoethanolamine, and a significant decrease of myo- and scyllo-inositol, in tumours with respect to mucosae. Among these metabolites, the high myo-inositol and taurine levels and the reciprocal changes found between them in tumours and mucosae make their resonances interesting as possible malignancy markers if they are detectable in vivo. In contrast to the easy observation of taurine in one-dimensional spectra of intact biopsies, the difficulty of observing myo-inositol prompted us to use two-dimensional COSY spectra for the detection and quantification of both these metabolites. In the two-dimensional spectra, the use of a ratio between the cross-peak volumes of both metabolites permits an excellent differentiation between tumours and normal mucosa and suggests its potential to detect malignant changes in the healthy tissue, provided a two-dimensional approach is used. PMID:8842031

Moreno, A; Arús, C

1996-02-01

169

A strong permanent magnet-assisted electromagnetic undulator  

DOEpatents

This invention discloses an improved undulator comprising a plurality of electromagnet poles located along opposite sides of a particle beam axis with alternate north and south poles on each side of the beam to cause the beam to wiggle or undulate as it travels generally along the beam axis and permanent magnets spaced adjacent the electromagnetic poles on each side of the axis of said particle beam in an orientation sufficient to reduce the saturation of the electromagnet poles whereby the field strength of the electromagnet poles can be increased beyond the normal saturation levels of the electromagnetic poles. 4 figs.

Halbach, K.

1987-01-30

170

Absorption Spectra and Energy Levels of Gd(3+), Nd(3+), and Cr(3+) in the Garnet Gd3Sc2Ga3O12.  

National Technical Information Service (NTIS)

Absorption spectra recorded between 0.3 and 6.7 micro are reported for trivalent gadolinium, trivalent neodymium, and trivalent chromium in single-crystal gadolinium scandium gallium garnet, Gd3Sc2Ga3O12, at liquid nitrogen, and room temperatures. Crystal...

J. B. Gruber M. E. Hills C. A. Morrison G. A. Turner M. R. Kokta

1988-01-01

171

Control over spectral characteristics of electromagnetic pulses  

NASA Astrophysics Data System (ADS)

A theory was elaborated on transition radiation (TR) from electron bunches that pass through diaphragms of various geometries. At the base of this theory are induced charges and currents in the conductive diaphragms that are generated by electron bunches. An important role of the earth points of diaphragms was proven experimentally and theoretically. A feasibility study was made on controlling the spectra of electromagnetic pulses (EMP) and their directivity patterns. A new configuration for the diaphragms was proposed: twin diaphragms. Calculated and experimentally measured were spectra of such EMPs that were formed by the induced conduction current during the flight of the electron bunch through the twin diaphragms.

Bolotov, V. N.; Fedorchenko, V. D.; Gritsenko, V. I.; Muratov, V. I.

2010-05-01

172

Electromagnetic cellular interactions.  

PubMed

Chemical and electrical interaction within and between cells is well established. Just the opposite is true about cellular interactions via other physical fields. The most probable candidate for an other form of cellular interaction is the electromagnetic field. We review theories and experiments on how cells can generate and detect electromagnetic fields generally, and if the cell-generated electromagnetic field can mediate cellular interactions. We do not limit here ourselves to specialized electro-excitable cells. Rather we describe physical processes that are of a more general nature and probably present in almost every type of living cell. The spectral range included is broad; from kHz to the visible part of the electromagnetic spectrum. We show that there is a rather large number of theories on how cells can generate and detect electromagnetic fields and discuss experimental evidence on electromagnetic cellular interactions in the modern scientific literature. Although small, it is continuously accumulating. PMID:20674588

Cifra, Michal; Fields, Jeremy Z; Farhadi, Ashkan

2010-07-30

173

Perfect electromagnetic conductor  

Microsoft Academic Search

In differential-form representation, the Maxwell equations are represented by simple differential relations between the electromagnetic two-forms and source three-forms while the electromagnetic medium is defined through a constitutive relation between the two-forms. The simplest of such relations expresses the electromagnetic two-forms as scalar multiples of one another. Because of its strange properties, the corresponding medium has been considered as nonphysical.

Ismo V. Lindell; Ari Sihvola

2005-01-01

174

Optical-absorption spectra, crystal-field energy levels, and transition line strengths of holmium in trigonal Na3[Ho(C4H4O5)3].2NaClO4.6H2O  

Microsoft Academic Search

Locations and assignments of 105 crystal-field levels are reported for Ho3+ in the trigonal Na3[Ho(oxydiacetate)3].2NaClO4.6H2O system. These levels were located and assigned from transitions observed in axial and sigma- and pi-polarized orthoaxial absorption spectra obtained on single-crystal samples at temperatures between 5 and 295 K. The absorption measurements spanned the 8000-37 000-cm-1 spectral region, and the assigned energy levels derive

D. M. Moran; Anne de Piante; F. S. Richardson

1990-01-01

175

Nonlinear electromagnetic wave equations for superdense magnetized plasmas  

SciTech Connect

By using the quantum hydrodynamic and Maxwell equations, we derive the generalized nonlinear electron magnetohydrodynamic, the generalized nonlinear Hall-MHD (HMHD), and the generalized nonlinear dust HMHD equations in a self-gravitating dense magnetoplasma. Our nonlinear equations include the self-gravitating, the electromagnetic, the quantum statistical electron pressure, as well as the quantum electron tunneling and electron spin forces. They are useful for investigating a number of wave phenomena including linear and nonlinear electromagnetic waves, as well as three-dimensional electromagnetic wave turbulence spectra and structures arising from mode coupling processes at nanoscales in dense quantum magnetoplasmas.

Shukla, Nitin; Brodin, G.; Marklund, M.; Shukla, P. K.; Stenflo, L. [Department of Physics, Umeaa University, Umeaa SE-90187 (Sweden)

2009-07-15

176

Second harmonic electromagnetic emission via beam-driven Langmuir waves  

SciTech Connect

The linked nonlinear processes of electrostatic Langmuir decay and electromagnetic emission at the second harmonic plasma frequency are studied for situations in which Langmuir waves are driven by an electron beam. An approximate method for studying wave decay and emission in three spatial dimensions is developed, based on the Langmuir and ion-acoustic wave dynamics in one spatial dimension. The numerical solutions of quasilinear equations to study electromagnetic emission starting from the electron dynamics are carried out. The numerical results are explored for illustrative parameters. The evolution of the transverse waves shows the combined effects of local emission and propagation away from the source. At a given location, the emission rate shows a series of peaks associated with coalescences of Langmuir waves driven by the beam and those produced by successive decays. The emission rate for a given coalescence decreases with time, following an initial increase. The effects of transverse wave propagation are illustrated by the presence of transverse waves both in regions upstream of the beam injection site due to backward propagation, and in regions downstream (e.g., where Langmuir waves are at thermal levels prior to the arrival of the beam) owing to forward propagation. Variation of the background electron to ion temperature ratio, beam injection parameters, and angular widths of the Langmuir spectra are found to affect the emission rate and the transverse wave levels. Furthermore, detailed studies show that the wave numbers of the maximum emission rates are in semiquantitative agreement with a previous theoretical prediction for simple model Langmuir spectra.

Li, B.; Willes, A.J.; Robinson, P.A.; Cairns, I.H. [School of Physics, University of Sydney, New South Wales 2006 (Australia)

2005-01-01

177

GENETIC EFFECTS OF ELECTROMAGNETIC WAVES  

Microsoft Academic Search

The genetic effects of electromagnetic waves can be detected by different test-systems. The mutagenic effect of ionizing radiation\\u000a can be developed on the levels of DNA and\\/or chromosomes. In numerous researches efficiency of micronucleus assay, alkaline\\u000a single-cell gel electrophoresis, chromosomal aberrations test and FISH-technique and their different combinations for the\\u000a detection of ionizing radiation-induced genotoxic effects are discussed. Also some

Rouben Aroutiounian; Galina Hovhannisyan; Gennady Gasparian

178

Electromagnetic fields stress living cells  

Microsoft Academic Search

Electromagnetic fields (EMF), in both ELF (extremely low frequency) and radio frequency (RF) ranges, activate the cellular stress response, a protective mechanism that induces the expression of stress response genes, e.g., HSP70, and increased levels of stress proteins, e.g., hsp70. The 20 different stress protein families are evolutionarily conserved and act as ‘chaperones’ in the cell when they ‘help’ repair

Martin Blank; Reba Goodman

2009-01-01

179

Genetic Effects of Electromagnetic Waves  

NASA Astrophysics Data System (ADS)

The genetic effects of electromagnetic waves can be detected by different test-systems. The mutagenic effect of ionizing radiation can be developed on the levels of DNA and/or chromosomes. In numerous researches efficiency of micronucleus assay, alkaline single-cell gel electrophoresis, chromosomal aberrations test and FISH-technique and their different combinations for the detection of ionizing radiation-induced genotoxic effects are discussed. Also some molecular-biological approaches developed in the last years are presented.

Aroutiounian, Rouben; Hovhannisyan, Galina; Gasparian, Gennady

180

Flame Spectra.  

ERIC Educational Resources Information Center

|When salt (NaCl) is introduced into a colorless flame, a bright yellow light (characteristic of sodium) is produced. Why doesn't the chlorine produce a characteristic color of light? The answer to this question is provided, indicating that the flame does not excite the appropriate energy levels in chlorine. (JN)|

Cromer, Alan

1983-01-01

181

Spectra of bigyrotropic magnetic photonic crystals  

NASA Astrophysics Data System (ADS)

We calculated the photonic band gap spectra of a one-dimensional magnetic photonic crystal made of alternating layers of bigyrotropic magnetic yttrium-iron garnet and nonmagnetic gadolinium gallium garnet. The forbidden regimes or band gaps in the electromagnetic wave spectrum were numerically obtained for the transversal magneto-optical configuration and compared with those for the polar and longitudinal magneto-optical configurations.

Lyubchanskii, I. L.; Dadoenkova, N. N.; Lyubchanskii, M. I.; Shapovalov, E. A.; Lakhtakia, A.; Rasing, Th.

2004-12-01

182

Electromagnetically Operated Counter  

DOEpatents

An electromagnetically operated counter wherein signals to be counted are applied to cause stepwise rotation of a rotatable element which is connected to a suitable register. The mechanism involved consists of a rotatable armature having three spaced cores of magnetic material and a pair of diametrically opposed electromagnets with a suitable pulsing circuit to actuate the magnets.

Goldberg, H.D.; Goldberg, M.I.

1950-01-31

183

Introducing Electromagnetic Field Momentum  

ERIC Educational Resources Information Center

|I describe an elementary way of introducing electromagnetic field momentum. By considering a system of a long solenoid and line charge, the dependence of the field momentum on the electric and magnetic fields can be deduced. I obtain the electromagnetic angular momentum for a point charge and magnetic monopole pair partially through dimensional…

Hu, Ben Yu-Kuang

2012-01-01

184

Photonic electromagnetic field probes  

Microsoft Academic Search

Summary form only given. Optically sensed probes designed to accurately measure electromagnetic fields are described. The probes use passive electrooptic modulators of Pockels cell or integrated optics designs to transfer the electromagnetic signal to an optical carrier propagating in a fibre-optic link. This approach eliminates the need for active components or power sources in the probe head. It minimizes the

M. Kanda; K. D. Masterson; D. R. Novotny

1992-01-01

185

Low frequency electromagnetic devices  

Microsoft Academic Search

The design, simulation and implementation of low frequency electromagnetic devices on planar structures are given. Planar devices and components are designed and built on a ceramic-based material that allowed a surface-mount (SMT) application. Method of moment based electromagnetic field solvers are used to verify the design of the devices. Planar devices and components are then implemented and tested. Simulation results

Abdullah Eroglu

2009-01-01

186

Tunability enhanced electromagnetic wiggler  

DOEpatents

The invention discloses a wiggler used in synchrotron radiation sources and free electron lasers, where each pole is surrounded by at least two electromagnetic coils. The electromagnetic coils are energized with different amounts of current to provide a wide tunable range of the on-axis magnetic flux density, while preventing magnetic saturation of the poles.

Schlueter, R.D.; Deis, G.A.

1991-03-20

187

Tunability enhanced electromagnetic wiggler  

DOEpatents

The invention discloses a wiggler used in synchrotron radiation sources and free electron lasers, where each pole is surrounded by at least two electromagnetic coils. The electromagnetic coils are energized with different amounts of current to provide a wide tunable range of the on-axis magnetic flux density, while preventing magnetic saturation of the poles. 14 figs.

Schlueter, R.D.; Deis, G.A.

1992-03-24

188

The Electromagnetic Spectrum  

NSDL National Science Digital Library

This tutorial introduces students to the concepts of electromagnetic waves, wavelength, and the electromagnetic spectrum. Diagrams and written descriptions explain how wavelength is measured and explore the traditional divisions of the spectrum: radio, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.

189

Tunability enhanced electromagnetic wiggler  

DOEpatents

The invention discloses a wiggler used in synchrotron radiation sources and free electron lasers, where each pole is surrounded by at least two electromagnetic coils. The electromagnetic coils are energized with different amounts of current to provide a wide tunable range of the on-axis magnetic flux density, while preventing magnetic saturation of the poles.

Schlueter, Ross D. (Albany, CA); Deis, Gary A. (Livermore, CA)

1992-01-01

190

Building an Electromagnet  

NSDL National Science Digital Library

Students design and construct an electromagnet that must pick up 10 staples. They begin with only minimal guidance, and after the basic concept is understood, are informed of the properties that affect the strength of that magnet. They conclude by designing their own electromagnet to complete the challenge of separating scrap steel from scrap aluminum for recycling and share it with the class.

Vu Bioengineering Ret Program

191

Beta Spectra. II-Positron Spectra.  

National Technical Information Service (NTIS)

Using the Fermi theory of beta decay, the beta spectra for 30 positron emitters have been computed, introducing a correction factor for unique forbidden transitions. The spectra are ploted vs. energy, once normalised, and tabulated with the related Fermi ...

A. Grau E. Garcia-Torano

1981-01-01

192

Features of the NCth in SEE spectra  

NASA Astrophysics Data System (ADS)

Basing on experiments carried out at the Sura heating facility it has been elaborated an empirical model for generation of the thermal narrow continuum NC th in stimulated electromagnetic emission SEE spectra which is observed in the lower sideband of the pump wave PW frequency extending up to the down-shifted maximum DM and the spectral intensity of which decreases exponentially with the increase of frequency shift from the pump The generation of NC th as well as DM and broad continuum BC occurs due to excitation of the thermal resonance parametric instability TPI Integral intensity of the NC th is close to or even higher than DM integral intensity The basic characteristics of the NC th are very similar to analogous DM ones Among them are magnitudes of their thresholds strong influence of HF-induced striations on their features dependences of their intensity on PW frequency PW power and heating antenna beam position relatively to the geomagnetic field gyro features typical times of their development after PW switch-on generation of these SEE components when a PW frequency is slightly below of F 2 -region critical frequency f 0F2 but an upper hybrid resonance frequency for the PW still remains below f 0F2 The intensity of the NC th as for DM has a maximal level in a PW frequency range from 5 to 7 MHz and it is fast reduced outside of this range The form of NC th spectra is often very similar to the spectral form of DM and its satellites DM1 and DM2 for their low frequency flanks

Frolov, V. L.; Nedzvetski, D. I.; Sergeev, E. N.

193

Cyclone Spectra  

NASA Astrophysics Data System (ADS)

As the resolution of climate models improves so will their ability to replicate the full spectrum of cyclones 'observed' in the atmosphere. This improved capability will need to be matched by improved techniques for locating and tracking cyclones in the model output. This presentation will advertise two such techniques, developed recently, and which have hitherto been used only on the output of shorter range oper- ational forecast models. As will be shown with examples, the techniques are particu- larly valuable at the extreme end of the range, where the most damaging cyclones are often small, fast-moving and relatively short-lived. Reference will also be made to a current North Atlantic climatology of low pres- sure centres and frontal waves, as diagnosed from a recently constructed 'cyclone database' put together using the above techniques. This database contains many at- tributes for each cylonic feature, including upper level jet diagnostics and a proxy for maximum surface gusts. Examples will be given of relationships derived from the database. Potentially these can also assist in the interpretation of climate model output, by providing an indirect means of inferring probabilities of extreme weather events.

Hewson, T. D.

194

Electromagnetic Interference Prediction in Transient Electromagnetic Environment  

Microsoft Academic Search

This paper presents an approach to predict the interference effects of a transient electromagnetic environment (EME) caused by an aggregate of wideband transmitters on a traditional narrowband victim. Due to the constraint of the narrowband receiver, it is sufficient to evaluate such wideband parameters of transmitter as effective isotropically radiated average power (EIRP) and antenna gains, etc. at the center

Yu Zhi-yong; Wang Jiang-feng

2007-01-01

195

Modal phenomena in the natural electromagnetic spectrum below 5 kHz  

NASA Astrophysics Data System (ADS)

This paper presents new measurements of the magnetic field component of naturally produced electromagnetic radiation in the ELF/VLF range. The measurements are compared to calculations based on modal propagation theory. The nocturnal spectrum below 5 kHz often contains a sharp increase in spectral level at the cutoff frequency of the first mode (˜1700 Hz) and a distinct variation of the spectral behavior at the cutoff frequency of the second mode (˜3400 Hz), where the indicated cutoff frequencies were calculated for perfectly conducting Earth and ionosphere, with the ionosphere 88 km above the Earth. These features are attributed to an enhancement in the first (quasi-transverse electric (QTE1)) and second (QTE2) propagating modes at night, which makes their level comparable to the basic (transverse electromagnetic) mode. Another spectral feature, which also prevails during the night, is semiperiodic fluctuations of the spectrum between the two cutoff frequencies, with a short period at the low end of the band and a gradual increase of the period as frequency increases. A similar semiperiodic fluctuation is apparent above the cutoff frequency of the second mode up to the limit of the measured band at 5 kHz. These semiperiodic fluctuations of the spectrum are related to the modal nature of the electromagnetic wave propagation. We show that computations of the spectrum of the ELF/VLF radiation emitted by a vertical lightning in the Earth-ionosphere waveguide gives spectra that compare well with the measurements.

Porrat, Dana; Bannister, Peter R.; Fraser-Smith, Antony C.

2001-05-01

196

[Characteristics of electromagnetic situation in Far North regions].  

PubMed

Coming to Far North from moderate climate area, humans face completely different, specific electromagnetic surroundings. Far North is a place with higher levels of Earth magnetic field, that is due to increased number of potent radiostations, radars, electric supply lines and other electromagnetic field sources. This specific complex of electromagnetic factors can contribute significantly to unfavorable changes in health state of Far Northern residents and requires thorough studies and careful attention. PMID:8963571

Pokhodze?, L V; Pal'tsev, Iu P

1996-01-01

197

Spectra Optia Apheresis System  

Center for Biologics Evaluation and Research (CBER)

... Spectra Optia Apheresis System. Applicant: Terumo BCT, Inc. 510(k) number: BK120076. Product: Spectra Optia® Apheresis System. ... More results from www.fda.gov/biologicsbloodvaccines/bloodbloodproducts/approvedproducts

198

Measurements of electromagnetic bias in radar altimetry  

Microsoft Academic Search

The accuracy of satellite altimetric measurements of sea level is limited in part by the influence of ocean waves on the altimeter signal reflected from the sea surface. The difference between the mean reflecting surface and mean sea level is the electromagnetic bias. The bias is poorly known, yet for such altimetric satellite missions as the Topography Experiment (TOPEX)\\/Poseidon it

W. K. Melville; R. H. Stewart; W. C. Keller; J. A. Kong; D. V. Arnold; A. T. Jessup; M. R. Loewen; A. M. Slinn

1991-01-01

199

Sensitivity analysis for electromagnetic topology optimization problems  

Microsoft Academic Search

This paper presents a level set based method to design the metal shape in electromagnetic field such that the incident current flow on the metal surface can be minimized or maximized. We represent the interface of the free space and conducting material (solid phase) by the zero-order contour of a higher dimensional level set function. Only the electrical component of

Shiwei Zhou; Wei Li; Qing Li

2010-01-01

200

[Autoimmune processes after long-term low-level exposure to electromagnetic fields (the results of an experiment). Part 2. General scheme and conditions of the experiment. Development of RF exposure conditions complying with experimental tasks. Animal's status during the long-term exposure].  

PubMed

This paper describes the conditions for handling and exposure of experimental animals (Wistar rats) and methods used in the study of immunological effects of long-term low-level (500 microW/cm2) exposure to radiofrequency (2450 MHz) electromagnetic fields, performed under auspices of the World Health Organization. PMID:20297675

Grigor'ev, Iu G; Grigor'ev, O A; Merkulov, A V; Shafirkin, A V; Vorob'ev, A A

201

Fluctuating electromagnetic fields of solids  

NASA Astrophysics Data System (ADS)

Various theoretical methods to calculate the spectral and correlation properties of fluctuating electromagnetic fields generated by solids are reviewed, all of which essentially reduce to solving the Maxwell equations for a specified geometry and boundary conditions and then using the fluctuation-dissipation theorem. The spectral and correlation properties of thermally stimulated fields of a system in equilibrium and out of equilibrium with surrounding bodies are described. A special attention is put to the difference between the spectral and correlation properties of the propagating and evanescent waves of the thermally stimulated fields of solids. The dispersion interaction between solid bodies in different thermodynamic states, the resonance dispersion interaction in a three-body system, the fluctuating fields as a means of body-to-body energy transfer, and the shift, broadening, and deexcitation of energy levels in a particle near a solid surface are discussed using the theory of thermally stimulated electromagnetic fields. Thermally stimulated emission of infrared radiation of semiconductor crystals and films (heated up to 150 °C) on metal substrates are measured in frequency range of vibrational polaritons both for propagating waves and for evanescent waves transformed into propagating waves due to ATR prism over the samples. The experimental results on thermally stimulated electromagnetic fields from solids are in qualitative and quantitative agreement with model calculations and theoretical expectations.

Dorofeyev, I. A.; Vinogradov, E. A.

2011-07-01

202

Interaction of extremely-low-frequency electromagnetic fields with humans.  

National Technical Information Service (NTIS)

At a macroscopic level, the effects of extremely low frequency (ELF) electromagnetic fields on humans are well understood based on fundamental physical principles, but far less is known about the nature of the interactions at a cellular or molecular level...

T. S. Tenforde

1991-01-01

203

What Are Electromagnetic Fields?  

MedlinePLUS

... the main sources of IF fields; and radio, television, radar and cellular telephone antennas, and microwave ovens ... environments.) Electromagnetic fields at high frequencies Mobile telephones, television and radio transmitters and radar produce RF fields. ...

204

Electromagnetically Induced Transparency.  

National Technical Information Service (NTIS)

We report the first observation of electromagnetically induced transparency in optically thick medium. The transparency results from a destructive interference of two dressed states which are created by applying a temporally smooth coupling laser between ...

A. Imamoglu K. J. Boiler S. E. Harris

1992-01-01

205

Electrodeless Electromagnetic Blood Flowmeter.  

National Technical Information Service (NTIS)

The report presents an evaluation of two electrodeless electromagnetic blood flowmeters which circumvent the electrode-tissue interface problem. The flowmeter establishes a traveling magnetic field, and the flow rate is then determined by using a pickup c...

E. S. Pierson F. N. Huffman

1969-01-01

206

Identifying Electromagnetic Attacks against Airports  

NASA Astrophysics Data System (ADS)

This work presents a new and sophisticated approach to detect and locate the origin of electromagnetic attacks. At the example of an airport, a normal electromagnetic environment is defined, in which electromagnetic attacks shall be identified. After a brief consideration of the capabilities of high power electromagnetic sources to produce high field strength values, this contribution finally presents the approach of a sensor network, realizing the identification of electromagnetic attacks.

Kreth, A.; Genender, E.; Doering, O.; Garbe, H.

2012-05-01

207

Electromagnetic navigation guided bronchoscopy  

PubMed Central

Abstract This review describes the technique and applications of an emerging bronchoscopic approach utilizing three-dimensional reconstructions of chest computed tomography scans to facilitate electromagnetic guidance to peripheral lung nodules. This approach, electromagnetic navigation bronchoscopy, is useful for biopsy, placement of fiducial markers, or dye marking of overlying pleura prior to thoracoscopic wedge resection. This technique offers some potential advantages over other forms of biopsy. The design, application, relative advantages and pitfalls of this system are the subject of this review.

2009-01-01

208

Electromagnetic rotational actuation.  

SciTech Connect

There are many applications that need a meso-scale rotational actuator. These applications have been left by the wayside because of the lack of actuation at this scale. Sandia National Laboratories has many unique fabrication technologies that could be used to create an electromagnetic actuator at this scale. There are also many designs to be explored. In this internship exploration of the designs and fabrications technologies to find an inexpensive design that can be used for prototyping the electromagnetic rotational actuator.

Hogan, Alexander Lee

2010-08-01

209

New electromagnetic conservation laws  

Microsoft Academic Search

The Chevreton superenergy tensor was introduced in 1964 as a counterpart, for electromagnetic fields, of the well-known Bel-Robinson tensor of the gravitational field. We here prove the unnoticed facts that, in the absence of electromagnetic currents, Chevreton's tensor (i) is completely symmetric, and (ii) has a trace-free divergence if the Einstein-Maxwell equations hold. It follows that the trace of the

G. Bergqvist; I. Eriksson; J. M. M. Senovilla

2003-01-01

210

Environmental and space electromagnetics  

Microsoft Academic Search

The present volume on environmental and space electromagnetics discusses spacecraft EM environment, natural and triggered lightning, atmospherics, whistlers, and emissions, and natural VLF\\/ELF radio noise. Attention is given to terrestrial and extraterrestrial noise environment, planetary lightning and cosmic plasma noise, noise and communication statistics, and space communication and measurement. Topics addressed include high-power electromagnetics, seismoelectric emissions, ball lightning, and meteorologico-electric

Hiroshi Kikuchi

1991-01-01

211

Nuclear deformations in the pairing-plus-quadrupole model (V). Energy levels and electromagnetic moments of the W, Os and Pt nuclei  

Microsoft Academic Search

The low-lying even-parity energy levels and wave functions of the even isotopes of tungsten, osmium and platinum are calculated within the framework of Bohr's collective Hamiltonian. The six kinetic energy functions and the potential energy function which enter the Hamiltonian, and which determine the coupling between rotational motion, beta-vibrations and gamma-vibrations, are derived microscopically by using the pairing-plus-quadrupole model of

Krishna Kumar; Michel Baranger

1968-01-01

212

Core-level X-ray photoelectron spectra and X-ray photoelectron diffraction of RuO 2(110) grown by molecular beam epitaxy on TiO 2(110)  

Microsoft Academic Search

We have measured Ru 3d, 4s, 4p and O 1s high-resolution core-level X-ray photoelectron spectra, along with Ru 3d and O 1s scanned-angle X-ray photoelectron diffraction angular distributions, for RuO2(110). The surfaces were prepared by oxygen-plasma-assisted molecular beam epitaxial growth of RuO2 on TiO2(110). XPS spectral interpretation and the nature of the XPD scans strongly suggest that the complex line

Y. J. Kim; Y. Gao; S. A. Chambers

1997-01-01

213

[Instrumental radiofrequency electromagnetic radiation dosimetry: general principals and modern methodology].  

PubMed

The modern experimental radiofrequency electromagnetic field dosimetry approach has been considered. The main principles of specific absorbed rate measurement are analyzed for electromagnetic field biological effect assessment. The general methodology of specific absorbed rate automated dosimetry system applied to establish the compliance of radiation sources with the safety standard requirements (maximum permissible levels and base restrictions) is described. PMID:22891551

Perov, S Iu; Kudriashov, Iu B; Rubtsova, N B

214

FOREWORD: Electromagnetic Phenomena and Health - A Continuing Controversy?  

Microsoft Academic Search

A variety of natural electromagnetic phenomena - from electrostatic and magnetostatic fields to radiowaves, microwaves, infrared, visible light, ultraviolet, X-rays and gamma radiation - may influence human health and wellbeing (by their presence, intensity or absence) in a number of diverse ways. Some artificially created electromagnetic phenomena may also directly and\\/or indirectly influence biological functioning, though the levels and extent

Isaac A. Jamieson; Paul Holdstock

2010-01-01

215

A remote sensor for electromagnetic personal safety monitoring  

Microsoft Academic Search

Abstract: Citizens are often afraid of electromagnetic fields. This creates a need for logging and quantifying the exposure to fields in the civil environment. An electromagnetic field strength sensor (from 1MHz to 1GHz) has been developed which is connected to a logging system and a modem. The systems output level is independent of frequencies i.e. follows the standards limit curve.

K. Pillet; F. Buesink; F. Leferink

2006-01-01

216

Network cables under lightning pulse: electromagnetic topology analysis  

Microsoft Academic Search

Summary form only given. We report on the response of cables when subjected to external electromagnetic pulse (EMP) such as lightning. Analysis was done through a technique called electromagnetic topology (EMT) method of simulation. In such a simulation method it is assumed that different volumes of various shielding level of an electrical system are independent of each other and interact

P. Kirawanich; R. Gunda; N. Kranthi; N. E. Islam

2004-01-01

217

Identification of new fluorescence processes in the UV spectra of cool stars from new energy levels of Fe II and CR II  

NASA Astrophysics Data System (ADS)

Two fluorescence processes operating in atmospheres of cool stars, symbiotic stars, and the Sun are presented. Two emission lines, at 1347.03 and 1360.17 A, are identified as fluorescence lines of Cr II and Fe II. The lines are due to transitions from highly excited levels, which are populated radiatively by the hydrogen Lyman alpha line due to accidental wavelength coincidences. Three energy levels, one in Cr II and two in Fe II, are reported.

Johansson, Sveneric; Carpenter, Kenneth G.

1988-06-01

218

Highly-Excited Levels of FEI Obtained from Laboratory and Solar Fourier Transform and Grating Spectra - Part Two - Laboratory and Solar Identifications  

NASA Astrophysics Data System (ADS)

New identifications of ˜2200 Fe I lines between 1700 Å and 5 ?m (59 000 cm-1 -2000 cm-1) due to highly-excited configurations are presented. These have been observed in hollow cathode lamps using Fourier transform and grating spectroscopy. About 1700 of the lines have been observed in the solar spectrum. A companion paper presents the experimental energy levels.

Nave, G.; Johansson, S.

1993-12-01

219

The influence of the unknown de-excitation pattern in the analysis of ?-decay total absorption spectra  

NASA Astrophysics Data System (ADS)

The method of analysis of ?-decay total absorption spectra in order to obtain ?-strength distributions is studied. The influence on the final result of unknown branching ratios in the electromagnetic de-excitation of levels in the daughter nucleus is investigated with the help of the statistical model of the population and decay of the nucleus. The total decay strength appears to be rather insensitive to assumptions on the branching ratios and the systematic uncertainty on the shape of the strength distribution is quantified.

Tain, J. L.; Cano-Ott, D.

2007-02-01

220

Theoretical energy level spectra and transition data for 4p64d2, 4p64d4f, and 4p54d3 configurations of W36+  

NASA Astrophysics Data System (ADS)

The ab initio quasirelativistic Hartree–Fock method developed specifically for the calculation of spectral parameters of heavy atoms and highly charged ions is used to derive transition data for a multicharged tungsten ion. The configuration interaction method is applied to include electron correlation effects. The relativistic effects are taken into account in the Breit–Pauli approximation for quasirelativistic Hartree–Fock radial orbitals. The energy level spectra, radiative lifetimes and Lande g-factors are calculated for the 4p64d2, 4p64d4f, and 4p54d3 configurations of the ion W36+. The transition wavelengths, spontaneous transition probabilities, oscillator strengths, and line strengths for the electric dipole, electric quadrupole, electric octupole, and magnetic dipole transitions among the levels of these configurations are tabulated.

Bogdanovich, P.; Kisielius, R.

2013-09-01

221

Perturbative corrections to the rotating-wave approximation for two-level molecules and the effects of permanent dipoles on single-photon and multiphoton spectra  

Microsoft Academic Search

Perturbative corrections are derived for the rotating-wave approximation (RWA) for the single-photon and multiphoton resonance profiles due to the interaction between a two-level molecule, with nonzero permanent dipoles, and a sinusoidal time-dependent electric field. The derivation is carried out through the use of a Floquet secular equation that introduces the effects of the permanent dipole moments into the problem through

Mary Ann Kmetic; William J. Meath

1990-01-01

222

MATHEMA: A Constructivist Enviroment for Electromagnetism Learning  

Microsoft Academic Search

In this paper we describe the Web-based adaptive educational hypermedia system called MATHEMA. In general, the MATHEMA is a learning system that dynamically generates courses in electromagnetism according to studentspsila learning goal, knowledge level, performance, learning style, abstract or concrete dimension of learning style, preference for visual and\\/or verbal feedback, preference for the kind of navigation, and preference of using

Alexandros Papadimitriou; Georgios Gyftodimos; Maria Grigoriadou

2009-01-01

223

Charging Ahead: An Introduction to Electromagnetism.  

ERIC Educational Resources Information Center

This guide explores the connection between electricity and magnetism with middle level and high school students. The phenomenon of electromagnetism is broken down into four lesson plans that provide students and teachers with a carefully constructed yet easy way to learn about their history. All four activities prompt students to use inexpensive,…

Shafer, Larry E.

224

Charging Ahead: An Introduction to Electromagnetism.  

ERIC Educational Resources Information Center

|This guide explores the connection between electricity and magnetism with middle level and high school students. The phenomenon of electromagnetism is broken down into four lesson plans that provide students and teachers with a carefully constructed yet easy way to learn about their history. All four activities prompt students to use inexpensive,…

Shafer, Larry E.

225

Metamaterial electromagnetic wave absorbers.  

PubMed

The advent of negative index materials has spawned extensive research into metamaterials over the past decade. Metamaterials are attractive not only for their exotic electromagnetic properties, but also their promise for applications. A particular branch-the metamaterial perfect absorber (MPA)-has garnered interest due to the fact that it can achieve unity absorptivity of electromagnetic waves. Since its first experimental demonstration in 2008, the MPA has progressed significantly with designs shown across the electromagnetic spectrum, from microwave to optical. In this Progress Report we give an overview of the field and discuss a selection of examples and related applications. The ability of the MPA to exhibit extreme performance flexibility will be discussed and the theory underlying their operation and limitations will be established. Insight is given into what we can expect from this rapidly expanding field and future challenges will be addressed. PMID:22627995

Watts, Claire M; Liu, Xianliang; Padilla, Willie J

2012-05-25

226

Electromagnetic properties of baryons  

SciTech Connect

We discuss the chiral behavior of the nucleon and {Delta}(1232) electromagnetic properties within the framework of a SU(2) covariant baryon chiral perturbation theory. Our one-loop calculation is complete to the order p{sup 3} and p{sup 4}/{Delta} with {Delta} as the {Delta}(1232)-nucleon energy gap. We show that the magnetic moment of a resonance can be defined by the linear energy shift only when an additional relation between the involved masses and the applied magnetic field strength is fulfilled. Singularities and cusps in the pion mass dependence of the {Delta}(1232) electromagnetic moments reflect a non-fulfillment. We show results for the pion mass dependence of the nucleon iso-vector electromagnetic quantities and present preliminary results for finite volume effects on the iso-vector anomalous magnetic moment.

Ledwig, T.; Pascalutsa, V.; Vanderhaeghen, M. [Institut fuer Kernphysik, Universitaet Mainz, D-55099 Mainz (Germany); Martin-Camalich, J. [Departamento de Fisica Teorica and IFIC, Universidad de Valencia-CSIC, Spain and Department of Physics and Astronomy, University of Sussex, BN1 9Qh, Brighton (United Kingdom)

2011-10-21

227

Gravitation electromagnetic theory  

NASA Astrophysics Data System (ADS)

The interrelationship existing between gravitation and electromagnetism is examined. A brief summary of the ideas which have guided scientific thought toward an understanding of gravitation is presented. The development of the electromagnetic theory is presented. The effects of the action of electromagnetic fields on the gravitational interactions are shown. On one side is, the explanation of various important cosmological phenomena, and on the other side, the path to control the gravitational interaction, which will foster the advent of gravitational propulsion, the foundations of which are established. The implications of this theory to the biological field are explored. In this field, the local control of gravitation opens the way to the study of the biological processes under several different conditions of gravity, which, in turn, may bring forth important results in biological research.

Deaquino, Fran

1988-03-01

228

Adjoint shape optimization applied to electromagnetic design.  

PubMed

We present an adjoint-based optimization for electromagnetic design. It embeds commercial Maxwell solvers within a steepest-descent inverse-design optimization algorithm. The adjoint approach calculates shape derivatives at all points in space, but requires only two "forward" simulations. Geometrical shape parameterization is by the level set method. Our adjoint design optimization is applied to a Silicon photonics Y-junction splitter that had previously been investigated by stochastic methods. Owing to the speed of calculating shape derivatives within the adjoint method, convergence is much faster, within a larger design space. This is an extremely efficient method for the design of complex electromagnetic components. PMID:24104043

Lalau-Keraly, Christopher M; Bhargava, Samarth; Miller, Owen D; Yablonovitch, Eli

2013-09-01

229

Electromagnetically induced transparency for x-rays.  

SciTech Connect

Electromagnetically induced transparency is predicted for x rays in laser-dressed neon gas. The x-ray photoabsorption cross section and polarizability near the Ne K edge are calculated using an ab initio theory suitable for optical strong-field problems. The laser wavelength is tuned close to the transition between 1s-13s and 1s-13p ({approx}800 nm). The minimum laser intensity required to observe electromagnetically induced transparency is of the order of 1012 W/cm2. The ab initio results are discussed in terms of an exactly solvable three-level model. This work opens new opportunities for research with ultrafast x-ray sources.

Buth, C.; Santra, R.; Young, L.; Chemistry

2007-06-22

230

Micronewton electromagnetic thruster  

NASA Astrophysics Data System (ADS)

A low cost and light electromagnetic thruster, consisting in a disc rigidly attached with a coaxial coil, shows steady recoil by losing its linear momentum. The signal applied in the device is a square electric potential. A continuous thrust is observed on the center-of-mass in one single direction under electromagnetic excitation for various voltages and nominal high frequencies. At 1 kHz with 20 V amplitude, the recoil force reaches 4 ?N (micronewton). The recoil is numerically quantified with induced electromotive and Lorentz forces. The presented device directly converts electric energy into kinetic energy.

Charrier, D. S. H.

2012-07-01

231

Introducing electromagnetic field momentum  

NASA Astrophysics Data System (ADS)

I describe an elementary way of introducing electromagnetic field momentum. By considering a system of a long solenoid and line charge, the dependence of the field momentum on the electric and magnetic fields can be deduced. I obtain the electromagnetic angular momentum for a point charge and magnetic monopole pair partially through dimensional analysis and without using vector calculus identities or the need to evaluate integrals. I use this result to show that linear and angular momenta are conserved for a charge in the presence of a magnetic dipole when the dipole strength is changed.

Yu-Kuang Hu, Ben

2012-07-01

232

Electromagnetically induced absorption via incoherent collisions  

SciTech Connect

We conduct theoretical studies on electromagnetically induced absorption via incoherent collisions in an inhomogeneously broadened ladder-type three-level system with the density-matrix approach. The effects of the collision-induced coherence decay rates as well as the probe laser field intensity on the probe field absorption are examined. It is shown that with the increase of the collisional decay rates in a moderate range, a narrow dip due to electromagnetically induced transparency superimposed on the Doppler-broadened absorption background can be turned into a narrow peak under the conditions that the probe field intensity is not very weak as compared to the pump field, which results from the enhancement of constructive interference and suppression of destructive interference between one-photon and multiphoton transition pathways. The physical origin of the collision-assisted electromagnetically induced absorption is analyzed with a power-series solution of the density-matrix equations.

Yang Xihua [Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701 (United States); Department of Physics, Shanghai University, Shanghai 200444 (China); Sheng Jiteng; Xiao Min [Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701 (United States)

2011-10-15

233

Review of Quantum Electromagnetic States.  

National Technical Information Service (NTIS)

This program provided a review of the conceptual and mathematical apparatus to apply modern theories of electromagnetic fields. As a study in low- noise electromagnetic states, it centers on the need to transition basic physics into the engineering arena ...

M. A. Parker

1999-01-01

234

Torsion and the Electromagnetic Field  

Microsoft Academic Search

In the framework of the teleparallel equivalent of general relativity, we study the dynamics of a gravitationally coupled electromagnetic field. It is shown that the electromagnetic field is able not only to couple to torsion, but also, through its energy-momentum tensor, produce torsion. Furthermore, it is shown that the coupling of the electromagnetic field with torsion preserves the local gauge

V. C. de Andrade; J. G. Pereira

1999-01-01

235

Geometrical Model of Electromagnetic Fields  

Microsoft Academic Search

The electrostatic field, electromagnetic waves, electromagnetic induction, and the pure magnetic field are illustrated and explained in terms of a single pictorial representation of the general electromagnetic field of a classical charged particle. The field of a charged particle is described by the orientation and density of a family of surfaces radially distributed about the path of the particle in

Edward S. Lowry

1963-01-01

236

Hidden relationship between the electrical conductivity and the Mn 2p core-level photoemission spectra in La1-xSrxMnO3  

NASA Astrophysics Data System (ADS)

Core-level electronic structure of La1-xSrxMnO3 has been studied by x-ray photoemission spectroscopy (XPS). We first report, by the conventional XPS, the well-screened shoulder structure in Mn 2p3/2 peak, which had been observed only by hard x-ray photoemission spectroscopy so far. Multiple-peak analysis revealed that the Mn4+ spectral weight was not proportional to the nominal hole concentration x, indicating that a simple Mn3+/Mn4+ intensity ratio analysis may result in a wrong quantitative elemental analysis. Considerable weight of the shoulder at x = 0.0 and the fact that the shoulder weight was even slightly going down from x = 0.2 to 0.4 were not compatible with the idea that this weight simply represents the metallic behavior. Further analysis found that the whole Mn 2p3/2 peak can be decomposed into four portions, the Mn4+, the (nominal) Mn3+, the shoulder, and the other spectral weight located almost at the Mn3+ location. We concluded that this weight represents the well-screened final state at Mn4+ sites, whereas the shoulder is known as that of the Mn3+ states. We found that the sum of these two spectral weight has an empirical relationship to the conductivity evolution with x.

Hishida, T.; Ohbayashi, K.; Saitoh, T.

2013-01-01

237

Health Aspects of Radio-Frequency Electromagnetic Radiation.  

National Technical Information Service (NTIS)

Many of the nonionizing electromagnetic radiation at certain frequencies, power levels, and exposure durations can produce biological effects or injury depending on multiple physical and biological variables. The pathophysiology is reviewed of exposure to...

M. Grandolfo

1974-01-01

238

Models of electromagnetic properties of composite media  

NASA Astrophysics Data System (ADS)

Electromagnetic composite materials have attracted much interest in recent years, due to their desirable microwave and optical applications. One class of these is negative refractive index materials, or double negative materials, in which both permittivity and permeability of materials are simultaneously negative. Many exciting potential applications of double negative materials have been proposed, such as the perfect lens and the cloaking device. Here, a simple-cubic lattice of identical, homogeneous or coated non-metallic spherical particles embedded in a matrix is analyzed. One contribution of this work is the derivation of an analytical formula for the threshold dielectric loss angle of spherical inclusions, above which DNG behavior of the system is extinguished. In addition, analytical formulas are derived from which double negative bandwidth of a simple-cubic lattice of identical, magnetodielectric homogeneous or coated spheres can be determined. Another case of interest is nanocomposites, which commonly consist of nanoparticles embedded in a polymer matrix. These materials show superior dielectric or mechanical performance by taking advantage of the merits of their individual non-hybrid components. In one manifestation, diblock copolymers can be utilized to spatially separate nanoparticles by incorporating them in one block, preferentially, to form a long-range ordered structure. By designing this structure, the electromagnetic properties can be tailored for potential applications in novel devices. Here, molecular dynamics of polymer matrices and nanocomposites is analyzed by parametric modeling of their dielectric spectra, supporting design of a composite with desired electromagnetic properties.

Liu, Jin

239

Electromagnetic Spectrum Management.  

National Technical Information Service (NTIS)

This report presents the results of an Air Force Occupational Survey of the Electromagnetic Spectrum Management career ladder, Air Force Specialty Code (AFSC) 3C1X2. Authority for conducting occupational surveys is contained in AFI 36-2623. Copies of this...

1997-01-01

240

Electromagnetic pulse bombs' defense  

Microsoft Academic Search

With the high power microwave devices development, the high power microwave electromagnetic pulse bombs (E-bombs) have become practical abroad. The development of conventional E-bombs devices allows their use in nonnuclear confrontations. E-bombs are powerful enough to damage communication, radar, navigation and computer systems. This paper discusses effects of EMP on electrical system and how to defend the EMP.

Bin Chen; Yongbin Wang; Juan Li; Jianzhong Wang

2007-01-01

241

Differential Forms in Electromagnetics  

NASA Astrophysics Data System (ADS)

An introduction to multivectors, dyadics, and differential forms for electrical engineers While physicists have long applied differential forms to various areas of theoretical analysis, dyadic algebra is also the most natural language for expressing electromagnetic phenomena mathematically. George Deschamps pioneered the application of differential forms to electrical engineering but never completed his work. Now, Ismo V. Lindell, an internationally recognized authority on differential forms, provides a clear and practical introduction to replacing classical Gibbsian vector calculus with the mathematical formalism of differential forms. In Differential Forms in Electromagnetics, Lindell simplifies the notation and adds memory aids in order to ease the reader's leap from Gibbsian analysis to differential forms, and provides the algebraic tools corresponding to the dyadics of Gibbsian analysis that have long been missing from the formalism. He introduces the reader to basic EM theory and wave equations for the electromagnetic two-forms, discusses the derivation of useful identities, and explains novel ways of treating problems in general linear (bi-anisotropic) media. Clearly written and devoid of unnecessary mathematical jargon, Differential Forms in Electromagnetics helps engineers master an area of intense interest for anyone involved in research on metamaterials.

Lindell, Ismo V.

2004-04-01

242

Computation of Electromagnetic Fields  

Microsoft Academic Search

This paper reviews some of the more useful, current and newly developing methods for the solution of electromagnetic fields. It begins with an introduction to numerical methods in general, including specific references to the mathematical tools required for field analysis, e.g., solution of systems of simultaneous linear equations by direct and iterative means, the matrix eigenvalue problem, finite difference differentiation

A. Wexler

1969-01-01

243

Physics 2000: Electromagnetic Waves  

NSDL National Science Digital Library

This website presents the physics of electromagnetic waves by describing the properties of waves, electric forces, force fields, and vibrating charges. Interactive animations and a question and answer "tutorial" format is used to present the information. Presentations about the applications of E&M waves are also included.

Goldman, Martin

2004-07-14

244

Electromagnetic radiation detector  

DOEpatents

An electromagnetic radiation detector including a collimating window, a cathode member having a photoelectric emissive material surface angularly disposed to said window whereby radiation is impinged thereon at acute angles, an anode, separated from the cathode member by an evacuated space, for collecting photoelectrons emitted from the emissive cathode surface, and a negatively biased, high transmissive grid disposed between the cathode member and anode.

Benson, Jay L. (Albuquerque, NM); Hansen, Gordon J. (Albuquerque, NM)

1976-01-01

245

Electromagnetic radiations from rocks  

Microsoft Academic Search

To test the possibility of the emission of electromagnetic waves from rocks, experiments have been made to measure the electric field by using mainly granite samples that were struck together or struck by a hammer or a weight and were fractured by a bending moment. The wide-band (10 Hz to 100 kHz) waveforms of electric signals were digitally recorded. Roughly

Toshio Ogawa; Kazuo Oike; Taiji Miura

1985-01-01

246

Estimation of sea level muon energy spectra in the energy range 0.2 GeV TO 10 GeV  

NASA Astrophysics Data System (ADS)

The vertical muon energy spectrum has been calculated in the energy range 0.2 GeV to 10 GeV using the latest directly measured primary cosmic ray nucleon spectrum . The primary cosmic ray nucleon spectrum has been calculated from the available measurements JACEE, CRN, SOKOL and the experiments done by Ramaty, Ryan, Seo, Badhwar on P, He, CNO, Ne -Si and Fe. Then using the superposition model the all nucleon spectrum has been constructed which makes the form N(E)dE = 1.13E-2.61 dE [cm2 .s.sr.GeV/n]-1 The pT integrated Lorentz invariant crosssections available from the CERN LEBC EHS data for ?± and K± production initiated by pp collisions has been fitted and then from the fitting parameters hadronic energy moments have been calculated. The adopted inelastic crosssection for pp interactions is 35 mb and the value of ?p-air cross-section has been adopted as 273 mb.The Z-factors have been corrected for p-air collisions using the methodology of Minorikawa and Mitsui. The Q-G plasma correction of Z-factors has also been made. Adopting the methodology of Arnon Dar and taking the other interaction parameters the modified production co-efficients gNM AT M have been calculated. To calculate the muon flux in this methode one has to estimate C? and CK for which we used the parametric values like B? = 1, BK = 0.632, pa = 2.3424, ?K = 1.048.Using those values, C? and CK have been found out to be 0.220137 and 0.007149 respectively. The survival probability of muons which are produced at atmospheric depth ?0 to survive down to atmospheric depth l has been calculated with the help of the average muon production depth ?0 = 100 gm-cm-2 and survival depth ?F = 1033 gmcm-2 , respectively. The energy loss of muon during its propagation through atmosphere has been calculated. Finally the vertical muon energy spectrum at sea level from conventinal meson decay has been estimated and compared with experimental data of CAPRICE-94 (1999), Allkofer et al.(1976), Allkofer et al. (1971) and Hayman and Wolfendale (1962). It is found that estimated vertical muon energy spectrum in the low energy range is well in agreement with the experimental results. The results of Caprice-94 are lying below our results may be due to the strong solar activity that causes a depression in the muon intensity near 1 GeV region.

Haldar, T. K.; Mitra, M.; Bhattacharyya, D. P.

247

Geometrization of the electromagnetic field and dark matter  

NASA Astrophysics Data System (ADS)

Fundamental concepts, symmetries and dynamic equations of the theory of dark matter are derived from the simple relation: everything in the concept of space and the concept of space in everything. It is shown that the electromagnetic field is the singlet state of the dark matter field and, hence, the last may be considered as a generalized electromagnetic field (shortly gef) and a simple solution is given to the old problem of connecting the electromagnetic field with geometric properties of the physical manifold itself. It is shown that gauge fixing renders the generalized electromagnetic field effectively massive while the Maxwell electromagnetic field remains massless. To learn more about interactions between matter and dark matter on the microscopic level (and to recognize the fundamental role of internal symmetry in this case), the general covariant Dirac equation is derived and its natural generalization is considered. The experiment is suggested to test the formulated theory.

Pestov, I. B.

2013-05-01

248

Electromagnetic targeting of guns  

SciTech Connect

This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Electromagnetic pulse (EMP) signals produced from explosives being fired have been reported in the literature for fifty years. When a gun is fired it produces an EMP muzzle blast signal. The strength and nature of these signals was first analyzed in the early 1970s, while the results were interesting, no follow-up studies were conducted. With modern detection and signal processing technology, we believe that these signals could be used to instantaneously locate guns of virtually all calibers as they fire. The objective of our one-year project was to establish the basic nature of these signals and their utility in the concept of electromagnetic targeting of guns.

Pogue, E.W.; Boat, R.M.; Holden, D.N.; Lopez, J.R. [and others

1996-10-01

249

Electromagnetic induction spectroscopy  

NASA Astrophysics Data System (ADS)

An object, made partly or wholly of metals, has a distinct combination of electrical conductivity, magnetic permeability, and geometrical shape and size. When the object is exposed to a low-frequency electromagnetic field, it produces a secondary magnetic field. By measuring the secondary field in a broadband spectrum, we obtain a distinct spectral signature that may uniquely identify the object. Based on the response spectrum, we attempt to 'fingerprint' the object. This is the basic concept of Electromagnetic Induction Spectroscopy (EMIS). EMIS technology may be particularly useful for detecting buried landmines and unexploded ordnance. By fully characterizing and identifying an object without excavation. We should be able to reduce significantly the number of false targets. EMIS should be fully applicable to many other problems where target identification and recognition (without intrusive search) are important. For instance, an advanced EMIS device at an airport security gate may be able to recognize a particular weapon by its maker and type.

Won, I. J.; Keiswetter, Dean A.

1998-09-01

250

An electromagnetic micro dynamometer  

Microsoft Academic Search

Performance of a planar magnetic VR micromotor is evaluated using an electromagnetically controlled load and planar gear coupling. Fabrication is based on extended LIGA processing methods. A new coil construction technique is described which uses wound micro-coils on a LIGA defined pre-fonn. A maximum rotational speed of 17,500 rpm is achieved for a 1000 pm diameter rotor with a maximum

T. R. Christenson; J. Klein; H. Guckel

1995-01-01

251

Electromagnetically Activated Hypersonic Ducts  

NASA Astrophysics Data System (ADS)

This paper explores the use of Electromagnetic Radiation as an alternative to combustion in Scramjet-like hypersonic engines. The radiation is absorbed by the flow, heating it and thereby providing an alternative to the heat derived from combustion in the Scramjet. The advantages and disadvantages of this system are explored and theoretical results are presented illustrating typical radiation pathlengths at different frequencies. Suggestions for further theoretical and practical work are also made.

MacLeod, C.

252

Electromagnetic tornadoes in space  

SciTech Connect

The exotic phenomenon of energetic-ion conic formation by plasma waves in the magnetosphere is considered. Two particular transverse heating mechanisms are reviewed in detail; lower-hybrid energization of ions in the boundary layer of the plasma sheet and electromagnetic ion cyclotron resonance heating in the central region of the plasma sheet. Mean particle calculations, plasma simulations and analytical treatments of the heating processes are described.

Chang, T.; Crew, G.B.; Retterer, J.M.

1988-01-01

253

Flash memory electromagnetic compatibility  

Microsoft Academic Search

This paper analyzes the radiated electromagnetic compatibility (EMC) behavior of AMD\\/Spansion Flash memory integrated circuits. Using The Engineering Society For Advanced Mobility Land Sea Air and Space (SAE) J1752\\/3 method, the peak RF noise (EMC with respect to radiated emissions) was measured for various technologies and product features, determining statistically valid sensitivity factors for several independent variables. The findings show

Adam D. Fogle; Don Darling; Richard C. Blish; Gene Daszko

2006-01-01

254

Method of electromagnetic exploration  

SciTech Connect

A method is described of electromagnetic exploration comprising the following steps: obtaining measures of two horizontal components of the earth's magnetic field at each reference sites; obtaining a measure of the vertical component of the earth's magnetic field for at least one exploratory site; and determining a measure of a multidimensional earth resistivity structure by correlating the measures of horizontal and vertical components of the earth's magnetic field.

Nekut, A.G. Jr.

1987-05-05

255

Electromagnetic Nondestructive Evaluation (III)  

Microsoft Academic Search

Within the context of non-destructive testing, the classical `Formulate-Solve-Interpret' model of problem solving becomes `Measure-Recover-Interpret'. But, before one can perform measurements, there must be appropriate instrumentation. In this book on electromagnetic non-destructive evaluation (ENDE) all these aspects (instrumentation, measurement, recovery and interpretation) are treated, though the major emphasis is on the recovery and interpretation aspects. The focus of the book,

R S Anderssen

2000-01-01

256

Electromagnetic polarizabilities of hadrons  

SciTech Connect

Electromagnetic polarizabilities of hadrons are reviewed, after a discussion of classical analogues. Differences between relativistic and non-relativistic approaches can lead to conflicts with conventional nuclear physics sum rules and calculational techniques. The nucleon polarizabilities are discussed in the context of the non-relativistic valence quark model, which provides a good qualitative description. The recently measured pion polarizabilities are discussed in the context of chiral symmetry and quark-loop models. 58 refs., 5 figs.

Friar, J.L.

1988-01-01

257

Hyperphysics: Electromagnetic Waves  

NSDL National Science Digital Library

This Wikipedia page contains a labeled diagram of an electromagnetic wave showing how the electric and magnetic vectors change as a wave moves through space. Text introduces the physics of the wave. Just above the diagram is a map of related concepts, depicted as a network. This page is part of the HyperPhysics Collection, which contains many short, illustrated pages on various areas of physics and astronomy.

Nave, Carl R.

2012-03-25

258

Banded electromagnetic stator core  

DOEpatents

A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups. 5 figures.

Fanning, A.W.; Gonzales, A.A.; Patel, M.R.; Olich, E.E.

1994-04-05

259

Banded electromagnetic stator core  

DOEpatents

A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups. 5 figs.

Fanning, A.W.; Gonzales, A.A.; Patel, M.R.; Olich, E.E.

1996-06-11

260

Emergent electromagnetism in solids  

NASA Astrophysics Data System (ADS)

The electromagnetic field (EMF) is the most fundamental field in condensed-matter physics. Interaction between electrons, electron-ion interaction and ion-ion interaction are all of electromagnetic origin, while the other three fundamental forces, i.e. the gravitational force and weak and strong interactions, are irrelevant in the energy/length scales of condensed-matter physics. Also the physical properties of condensed matter, such as transport, optical, magnetic and dielectric properties, are almost described as their electromagnetic responses. In addition to this EMF, it often happens that the gauge fields appear as the emergent phenomenon in the low-energy sector due to the projection of the electronic wavefunctions onto the curved manifold of the Hilbert sub-space. These emergent EMFs play important roles in many places in condensed-matter physics including the quantum Hall effect, strongly correlated electrons and also in non-interacting electron systems. In this paper, we describe the fundamental idea behind it and some of its applications studied recently.

Nagaosa, Naoto; Tokura, Yoshinori

2012-01-01

261

Gravitation and electromagnetism  

NASA Astrophysics Data System (ADS)

The theory of general relativity unifies gravitation with the geometry of spacetime by replacing the scalar Newtonian gravitational potential with the symmetric metric tensor gmunu of a four-dimensional general Riemannian manifold by means of the equivalence principle. As is well known, the electromagnetic field has resisted all efforts to be interpreted in terms of the geometrical properties of space-time as well. In this investigation, we show that the electromagnetic field may indeed be given a geometrical interpretation in the framework of a modified version of general relativity - unimodular relativity. According to the theory of unimodular relativity developed by Anderson and Finkelstein, the equations of general relativity with a cosmological constant are composed of two independent equations, one which determines the null-cone structure of space-time, another which determines the measure structure of space-time. The field equations that follow from the restricted variational principle of this version of general relativity only determine the null-cone structure and are globally scale-invariant and scale-free. We show that the electromagnetic field may be viewed as a compensating gauge field that guarantees local scale invariance of these field equations. In this way, Weyl's geometry is revived. However, the two principle objections to Weyl's theory do not apply to the present formulation: the Lagrangian remains first order in the curvature scalar and the non-integrability of length only applies to the null-cone structure.

Bock, Robert Davis

262

Ejs Electromagnetic Wave Model  

NSDL National Science Digital Library

The Ejs Electromagnetic Wave model displays the electric field of an electromagnetic wave. The simulation allows an arbitrarily polarized wave to be created. The magnitude of the electric field components and the relative phase between the components of the electric field can all be changed via sliders. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting âOpen Ejs Modelâ from the pop-up menu item. Ejs Electromagnetic Wave model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_ehu_waves_emwave.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for wave optics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Aguirregabiria, Juan

2008-08-20

263

Coherent hybrid electromagnetic field imaging  

DOEpatents

An apparatus and corresponding method for coherent hybrid electromagnetic field imaging of a target, where an energy source is used to generate a propagating electromagnetic beam, an electromagnetic beam splitting means to split the beam into two or more coherently matched beams of about equal amplitude, and where the spatial and temporal self-coherence between each two or more coherently matched beams is preserved. Two or more differential modulation means are employed to modulate each two or more coherently matched beams with a time-varying polarization, frequency, phase, and amplitude signal. An electromagnetic beam combining means is used to coherently combine said two or more coherently matched beams into a coherent electromagnetic beam. One or more electromagnetic beam controlling means are used for collimating, guiding, or focusing the coherent electromagnetic beam. One or more apertures are used for transmitting and receiving the coherent electromagnetic beam to and from the target. A receiver is used that is capable of square-law detection of the coherent electromagnetic beam. A waveform generator is used that is capable of generation and control of time-varying polarization, frequency, phase, or amplitude modulation waveforms and sequences. A means of synchronizing time varying waveform is used between the energy source and the receiver. Finally, a means of displaying the images created by the interaction of the coherent electromagnetic beam with target is employed.

Cooke, Bradly J. (Jemez Springs, NM); Guenther, David C. (Los Alamos, NM)

2008-08-26

264

Structural, optical and electromagnetic properties of aluminum-clay nanocomposites  

NASA Astrophysics Data System (ADS)

Aluminum pillared and exchanged bentonite particles were synthesized by the ion exchange method. The characteristics of the particles were investigated by Fourier-transform infrared spectra (FTIR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), scanning electron microscope (SEM), electron dispersive X-ray spectrometer (EDS), reflectance spectrophotometer (RS) and electromagnetic transition instrument (ETI). FTIR spectra showed a successful incorporation of Al complexes into the clay interlayer. The TGA result demonstrated an improvement in thermal stability of the Al-pillared clay compared with the untreated particles. SEM and EDX results showed the presence of aluminum aggregates on the surface of clay. It was also found that Al ions affect electromagnetic properties of the clay particles.

Gashti, Mazeyar Parvinzadeh; Eslami, Shima

2012-01-01

265

Broadband cavity electromagnetically induced transparency  

SciTech Connect

Cavity electromagnetically induced transparency (EIT) is created in a three-level atomic system confined in a cavity and coupled to a free-space control laser and is manifested as a narrow transmission peak of a probe laser coupled into the cavity mode and tuned to the two-photon Raman resonance with the control laser. Cavity EIT can be observed with a control laser detuned from the atomic transition frequency in a range limited by the vacuum Rabi splitting of two cavity-atom normal modes. This leads to the broadband cavity EIT obtained in the coupled-cavity-atom system with a free-space, broadband control laser. We report an experimental observation of broadband cavity EIT in cold Rb atoms with a frequency-modulated control laser and discuss its application in multichannel and multifrequency light memory.

Wei Xiaogang [Department of Physics, Florida International University, Miami, Florida 33199 (United States); College of Physics, Jilin University, Changchun 130023 (China); Wang Yanhua [Department of Physics, Florida International University, Miami, Florida 33199 (United States); College of Physics and Electronics, Shanxi University, Taiyuan 030006 (China); Zhang Jiepeng [Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China); Physics Division P-23, Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States); Zhu Yifu [Department of Physics, Florida International University, Miami, Florida 33199 (United States)

2011-10-15

266

Electromagnetic Radiations Emanating From A Quenched Superconducting Electromagnet  

Microsoft Academic Search

A qualitative discussion is presented on the subject of electromagnetic radiations emanating from an arc discharge which is the result of an accidentally quenched superconducting electromagnet. The discussion is based upon the assumption that the electromagnet is the B-field source of a sea-going vessel’s magnetohydrodynamic, MHD. power plant. Should such a vessel be one which operates subsurface, it then seems

S. A. Marshall; D. G. Yerg

1990-01-01

267

Electromagnetic coupling and plasmon localization in deterministic aperiodic arrays  

Microsoft Academic Search

In this paper we explore the potential of one-dimensional and two-dimensional deterministic aperiodic plasmonic arrays for the design of electromagnetic coupling and plasmon-enhanced, sub-wavelength optical fields on chip-scale devices. In particular, we investigate the spectral, far-field and near-field optical properties of metal nanoparticle arrays generated according to simple deterministic sequences characterized by fractal Fourier spectra. Additionally, we will consider the

Luca Dal Negro; Ning-Ning Feng; Ashwin Gopinath

2008-01-01

268

Electromagnetic fields in bone repair and adaptation  

NASA Astrophysics Data System (ADS)

The treatment of delayed union of bone fractures has served for the past 20 years as the principal testing ground for determining whether nonionizing electromagnetic fields can have any substantial, long-term effects in clinical medicine. Recent double-blinded clinical trials have confirmed the significance of the reported effects on bone healing and have led to the suggestion that electromagnetic fields may also be useful in the treatment of other orthopedic problems such as fresh fractures, stabilization of prosthetic implants, or even the prevention or treatment of osteoporosis. However, the design of appropriate treatment regimens for these new applications would be greatly facilitated if it were understood how the biological cells within bone tissue sense these low-frequency, and remarkably low level, electromagnetic fields. Here we address the engineering and physical science aspects of this problem. We review the characteristics of clinically used electromagnetic fields and discuss which components of these fields may actually be responsible for altering the activity of the bone cells. We then consider several physical mechanisms which have been proposed to explain how the cells within the bone or fracture tissue detect this field component.

McLeod, Kenneth J.; Rubin, Clinton T.; Donahue, Henry J.

1995-01-01

269

Libraries of Stellar Spectra  

NSDL National Science Digital Library

This is a guide to online and abstract libraries of stellar spectra. This reference list also includes information about the spectra of Late-M, L, and T Dwarf stars, Morgan-Keenan spectral classification, the solar spectrum, spectrophotometric atlases, and automated and neural network classification.

2005-04-25

270

Spectra from Space  

NSDL National Science Digital Library

This site from the Exploratorium provides information on telescopes and observatories such as the Hubble Space Telescope that are being used to study spectra from space. Gamma-ray, x-ray, ultraviolet, and infrared spectra are all examined. The purpose and discoveries made by each observatory are included along with related hands-on activities like a liquid crystal IR detector activity.

Felter, Neil

2006-07-20

271

Space physics and the teaching of undergraduate electromagnetism  

NASA Astrophysics Data System (ADS)

Space physics is not a subject typically found in the undergraduate curriculum and it is rare even at the graduate level On the other hand the basis of space physics is electromagnetism and the motion of charged particles which is a common topics in both the introductory and advanced undergraduate physics curriculum This presentation will discuss various topics commonly found in both introductory and upper-division electricity and magnetism classes where examples from space physics may facilitate student understanding or provide interesting real-life examples of electromagnetism in action We chose these examples based on current research around student difficulties with electromagnetic phenomena and we will provide preliminary evidence on the efficacy of our interventions I will also discuss research in visualization of 3-D magnetic fields and the implications for teach both space physics and regular electromagnetism at both the graduate and undergraduate levels

Lopez, R.; Mitchell, E.

272

Plane Electromagnetic Wave in PEMC  

Microsoft Academic Search

Plane electromagnetic wave propagating in perfect electromagnetic conductor\\u000a(PEMC) is considered. Its wave number has no connection with the frequency. An\\u000ainterface is introduced between an ordinary isotropic medium and PEMC. The wave\\u000ain PEMC is matched to plane electromagnetic wave incident normally on the\\u000ainterface from the ordinary medium and reflected from it. Then the\\u000aplane-parallel slab made of

Bernard Jancewicz

2006-01-01

273

Torsion and the Electromagnetic Field  

Microsoft Academic Search

In the framework of the teleparallel equivalent of general relativity, we\\u000astudy the dynamics of a gravitationally coupled electromagnetic field. It is\\u000ashown that the electromagnetic field is able not only to couple to torsion, but\\u000aalso, through its energy-momentum tensor, to produce torsion. Furthermore, it\\u000ais shown that the coupling of the electromagnetic field with torsion preserves\\u000athe local

V. C. de Andrade; J. G. Pereira

1997-01-01

274

Electromagnetic Turbulence Simulations with Kinetic Electrons  

NASA Astrophysics Data System (ADS)

Recently a new electromagnetic kinetic electron delta-f particle simulation model has been demonstrated to work well at large values of plasma beta times the ion-to-electron mass ratio [1,2]. The new simulation presented here uses a generalized split-weight scheme [3,4], where the adiabatic part is adjustable, along with a parallel canonical momentum formulation [5] and has been developed in three-dimensional toroidal flux-tube geometry. The model also includes electron-ion collisional effects and has been linearly benchmarked with continuum codes [6,7]. Electromagnetic simulations with kinetic electrons require a timestep approximately one-half that of electrostatic adiabatic electron simulations. Large box size simulations of 256 by 256 in units of ion gyroradius using a realistic mass ratios run well and detailed convergence studies have been done. Finite-beta reduction of energy transport, below the adiabatic electron level is observed for betas below the kinetic ballooning limit. For beta above the kinetic ballooning threshold fluxes are extremely high, and it is unlikely to be an experimentally relevant regime. Zonal flows with kinetic electrons are found to be turbulent with the spectrum peaking at zero and having a width in the frequency range of the driving turbulence. This is in contrast with adiabatic electron cases where the zonal flows are near stationary. We have shown that the linear behavior of the zonal flow is not significantly affected by kinetic electrons. Zonal fields [9] are found to be very weak consistent with theoretical predictions for betas below the kinetic ballooning limit. Detailed spectral and cross-correlation analysis of the turbulent spectra will be presented in the various limits. Acknowledgments: Thanks to A.M. Dimits, D. Shumaker, LLNL; V.K. Decyk, J.N. Leboeuf UCLA, work done using the Summit Framework and supported by the DOE SciDAC Plasma Microturbulence Project. [1] Y. Chen and S.E. Parker, to appear in J. Comput. Phys. (2003). [2] Y. Chen, S.E. Parker, B.I. Cohen, A.M. Dimits, W.M. Nevins, D. Shumaker, V.K. Decyk and J.N. Leboeuf, to appear in Nuc. Fusion (2003). [3] I. Manuilskiy and W.W. Lee, Phys. Plasmas 7 1381 (2000). [4] Y. Chen and S.E. Parker, Phys. Plasmas 8 2095 (2001) [5] T.S. Hahm, W.W. Lee and A. Brizard, Phys. Fluids 31 1940 (1988). [6] W. Dorland et. al, Proc. 18th Int. Conf. on Fusion Energy, IAEA, Sorrento, Italy, 2000; W. Dorland, F. Jenko, M. Kotschenreuther and B.N. Rogers, Phys. Rev. Lett. 85, 5336 (2000). [7] J. Candy and R. Waltz, to appear in J. Comput. Physics (2003). [8] A.V. Gruzinov and P.H. Diamond, Phys. Plasmas 3 1854 (1996), L. Chen, Z. Lin R.B. White and F. Zonca, Nuc. Fusion 41 747 (2001); P.N. Gudzar, R.G. Kleva, A. Das and P.K. Kaw, Phys. Plasmas 8 3907 (2001).

Parker, Scott E.

2003-10-01

275

Radio frequency electromagnetic fields: mild hyperthermia and safety standards  

Microsoft Academic Search

This chapter is a short review of literature that serves as the basis for current safe exposure recommendations by ICNIRP (International Commission on Non-Ionizing Radiation Protection, 1998). and the IEEE C95.1 (IEEE Standard for Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3kHz to 300GHz, 2005) for exposure to radio frequency electromagnetic radiation (RF-EMF). Covered here

John A. D’Andrea; John M. Ziriax; Eleanor R. Adair

2007-01-01

276

Phase characteristics of electromagnetic stirring  

SciTech Connect

Electromagnetic stirring is used at billet molds as well as at slab mold, to get high quality steel at continuous casting in steel making plant. In order to get the same electromagnetic force in each billet mold and thus the same quality, phase characteristics of electromagnetic stirring is investigated. From the calculation result, it is found that the relative phase at which the difference of the electromagnetic torque in each mold becomes the smallest is 0 or 240 deg. To apply the phase characteristics of the EMS to the quality control, the authors propose the dynamic phase control system by two inverters to get the high quality in the surface crack.

Fujisaki, Keisuke; Ueyama, Takatsugu [Nippon Steel Corp., Futtsu, Chiba (Japan). Process Research Lab.; Takahashi, Keiichi [Nippon Steel Corp., Muroran, Hokkaido (Japan). Muroran Works; Satoh, Shouji [Ohita Plant Design Corp. (Japan)

1997-09-01

277

Units of ring spectra and Thom spectra  

Microsoft Academic Search

We review and extend the theory of Thom spectra and the associated\\u000aobstruction theory for orientations. We recall (from May, Quinn, and Ray) that\\u000aa commutative ring spectrum A has a spectrum of units gl(A). To a map of\\u000aspectra f: b -> bgl(A), we associate a commutative A-algebra Thom spectrum Mf,\\u000awhich admits a commutative A-algebra map to R

Matthew Ando; Andrew J. Blumberg; David J. Gepner; Michael J. Hopkins; Charles Rezk

2008-01-01

278

Long term electromagnetic monitoring at Parkfield, CA  

NASA Astrophysics Data System (ADS)

Electric and magnetic fields in the (10-4-1.0) Hz band were monitored at two sites adjacent to the San Andreas Fault near Parkfield and Hollister, California. Observed fields typically comprise natural magnetotelluric fields, with cultural and instrument noise. A data window [2002-2005], enclosing the September 28, 2004 M6 Parkfield earthquake, was analyzed to determine if anomalous electric or magnetic fields, or changes in ground conductivity, occurred before the earthquake. The data were edited, removing intervals of instrument malfunction, leaving 875 days left in the four-year period. Frequent, local spike-like disturbances were removed. The distribution of these spikes was not biased around the time of the earthquake. Signal to noise ratios, estimated via magnetotelluric processing techniques, provided an index of data quality. Plots of signal and noise amplitude spectra, showed the behavior of the ULF fields to be remarkably constant over the period of analysis. From these first-order plots, it is clear that most of the recorded energy is coherent over the spatial extent of the array. Three main statistical techniques were employed to separate local anomalous electrical or magnetic fields from the dominant coherent natural fields: transfer function estimates between components at each site were employed to subtract the dominant field, and look deeper at the 'residual' fields; the data were decomposed into principal components to identify linear combinations of array channels, which are maximally uncorrelated; the technique of canonical coherences was employed to distinguish anomalous fields which are spatially broad from anomalies which occur at a single site only, and furthermore to distinguish anomalies which are present in both the electric and magnetic fields form those which are present in only one field type. Standard remote reference apparent resistivity estimates were generated daily at Parkfield. Most of the variation was observed to be seasonal, and frequency independent, suggesting a local seasonal distortion effect. Once corrected for distortion, nearly all of the variability in the apparent resistivity was removed. In all cases, high levels of sensitivity to subtle electromagnetic effects were demonstrated, but no effects which can be described as precursors to the Parkfield earthquake were found.

Kappler, Karl Neil

279

Electromagnetic studies in geothermal regions  

NASA Astrophysics Data System (ADS)

During the past 25 yr, nearly all available electromagnetic and geoelectric techniques have been tested for their usefulness in geothermal exploration and exploitation. Dipole-dipole profiling, audiomagnetotellurics and controlled source electromagnetic methods are examples of those which have proven to be rather efficient for geothermal exploration. From the hundreds of field surveys which have been performed in many geothermal regions of the world, a large variety of geothermal regions and local geothermal systems, with different geological, hydrological and heat transfer characteristics, has been found to exist. Depending on the combination of these different characteristics each geothermal region or system presents a new problem which may need a different field technique or group of field techniques for optimal exploration. Despite these problems, new geothermal regions have been detected and structures and processes in geothermal systems are now much better understood. For example, advances have been made in the study of (a) the characteristics of porous/permeable hot water/vapor reservoirs and of fractioned zones for hot water/vapor circulation and production (b) the distribution and movement of cold meteoric and of hot water (c) the thermal insulation of reservoirs by cap-rocks (d) convective and/or conductive heat transfer and (e) the thermal influence of magma intrusions to high crustal levels. New exploration techniques, data analysis procedures and model calculations have been developed in the course of research in geothermal areas. They include the controlled source electromagnetic methods, the remote reference field technique and the development of better and faster algorithms for direct and inverse model calculations. Problems for the future are (a) the development and improvement of equipment and field techniques for more precise delineation and resolution of the conductivity distribution in geothermal areas especially those with productive zones of high porosity/permeability and fracturing, (b) the improvement of computerised data analysis in the field to optimise progress during the field measurements and (c) the development of more efficient interpretation procedures for the rather inhomogeneous conductivity distribution which exists in most geothermal areas.

Berktold, A.

1983-07-01

280

Cognitive Effects of Electromagnetic Fields in Humans  

Microsoft Academic Search

\\u000a Electromagnetic fields interact with human tissue in a number of ways, depending on power level and frequency, and have been\\u000a long suspected by some to give rise to harmful effects. In particular, the use of a mobile phone against the head has aroused\\u000a suspicions of various cognitive effects. Accordingly, there have been a large number of studies of behavioural effects

Alan W. Preece

281

Electromagnetic wave velocities: an experimental approach  

NASA Astrophysics Data System (ADS)

We describe experiments with coaxial transmission lines for the study of some of the velocities used to characterize the propagation of electromagnetic waves in a medium, namely phase, group and signal velocities. The experiments are suitable for undergraduates at advanced laboratory level. Their purpose is to acquaint the students with the fact that in a dispersive medium there are many possible definitions for the speed of light, and that the measurement of these different velocities is important for general understanding of wave propagation.

Santos, A. C. F.; Santos, W. S.; Aguiar, C. E.

2013-05-01

282

Interpreting marine controlled source electromagnetic field behaviour with streamlines  

NASA Astrophysics Data System (ADS)

Streamlines represent particle motion within a vector field as a single line structure and have been used in many areas of geophysics. We extend the concept of streamlines to interactive three dimensional representations of the coupled vector fields generated during marine controlled source electromagnetic surveys. These vector fields have measurable amplitudes throughout many hundreds of cubic kilometres. Electromagnetic streamline representation makes electromagnetic interactions within complex geo-electrical setting comprehensible. We develop an interface to rapidly compute and interactively visualise the electric and magnetic fields as streamlines for 3D marine controlled source electromagnetic surveys. Several examples highlighting how interactive use has value in marine controlled source electromagnetic survey design, interpretation and teaching are provided. The first videos of electric, magnetic and Poynting vector field streamlines are provided along with the first published example of the airwave represented as streamlines. We demonstrate that the electric field airwave is a circulating vortex moving down and out from the air–water interface towards the ocean floor. The use of interactive streamlines is not limited to marine controlled source electromagnetic methods. Streamlines provides a high level visualisation tool for interpreting the electric and magnetic field behaviour generated by a wide range of electromagnetic survey configurations for complex 3D geo-electrical settings.

Pethick, A. M.; Harris, B. D.

2013-10-01

283

Electromagnetic pump stator coil  

SciTech Connect

An electrical stator coil for an electromagnetic pump includes a continuous conductor strip having first and second terminals at opposite ends thereof and an intermediate section disposed therebetween. The strip is configured in first and second coil halves, with the first coil half including a plurality of windings extending from the first terminal to the intermediate section, and the second coil half including a plurality of windings extending from the second terminal to the intermediate section. The first and second coil halves are disposed coaxially, and the first and second terminals are disposed radially inwardly therefrom with the intermediate section being disposed radially outwardly therefrom. 9 figs.

Fanning, A.W.; Dahl, L.R.

1996-06-25

284

All electromagnetic form factors  

NASA Astrophysics Data System (ADS)

The electromagnetic form factors of spin-1/2 particles are known, but due to historical reasons only half of them are found in many textbooks. Given the importance of the general result, its model independence, its connection to discrete symmetries and their violations we made an effort to derive and present the general result based only on the knowledge of the Dirac equation. We discuss the phenomenology connected directly with the form factors, and spin precession in external fields including time-reversal violating terms. We apply the formalism to spin-flip synchrotron radiation and suggest pedagogical projects.

Nowakowski, M.; Paschos, E. A.; Rodríguez, J. M.

2005-07-01

285

Electromagnetics. Second edition  

SciTech Connect

This book presents an account of the fundamentals of electromagnetic theory, giving readers an intuitive grasp of the subject. Emphasis is on the physical basis of the subject, but without undue neglect of mathematics. It includes topics not usually found in the standard texts. It also includes new sections on hysteresis, coaxial waveguides, radiation pressure, scattering by bound charge, and reflection by the ionosphere. In addition it contains 20 new, fully worked examples that illustrate applications to some problems of practical complexity. Finally, it bridges the gap between highly mathematical works and the usual, less rigorous formulations of the subject, and thus provides an easily understandable introduction to the subject.

Laud, B.B.

1987-01-01

286

Electromagnetic transitions in hypernuclei  

SciTech Connect

The object of this review is to survey observations of electromagnetic transitions in hypernuclei and to point out contributions of these observations to an understanding of the effective two-body hyperon-nucleon forces in the nucleus. The discussion concentrates on lambda-hyperon nucleon potentials. Future plans for high resolution hypernuclear spectroscopy using Ge diode detectors is discussed, especially regarding the window of utility of such devices. Expected improvements in beam facilities are also reviewed. 9 refs., 4 figs., 1 tab. (DWL)

Chrien, R.E.

1986-01-01

287

The ALICE electromagnetic calorimeter  

NASA Astrophysics Data System (ADS)

ALICE is the general purpose experiment at the LHC dedicated to the study of heavy-ion collisions. The electromagnetic calorimeter (EMCal) is a late addition to the ALICE suite of detectors with first modules installed in ALICE this year. The EMCal is designed to trigger on high energy gamma-rays and jets, and to enhance the capabilities of ALICE for these measurements. The EMCal is a Pb/scintillator sampling shish-kebab type calorimeter. The EMCal construction, readout, and performance in beam tests at the CERN SPS and PS are described.

Awes, Terry C.; ALICE Collaboration

2010-05-01

288

Spectra from Space  

NSDL National Science Digital Library

This resource explains why we go to the expense of launching satellites to gather spectral data in space. The earth's atmosphere does not allow light of all wavelengths to pass through it. In order to see gamma, X ray, ultraviolet (UV), infrared, and microwave radiation, we must place telescopes and other light-gathering instruments above the atmosphere. At this site, students investigate satellite missions operating in four electromagnetic bands using the internet and hands-on activities. After successfully completing these activities, students will be able to identify four different regions of the electromagnetic spectrum and order them by wavelength, describe one or more of the four satellite missions featured in the site, its capabilities, and some objects it is used to observe, and conduct and draw appropriate conclusions from some or all of four hands-on activities.

289

Incoherent radar spectra  

Microsoft Academic Search

General expressions for the incoherent scatter spectra are presented. These are relevant for the UHF radar in the monostatic backscatter case (thus excluding only the effect of the magnetic field), based on the Nyquist approach.

Matti K. Vallinkoski

1987-01-01

290

Spectra over complex terrain  

SciTech Connect

Spectra have been measured over land downwind of a water surface, over hilltops and escarpments, and over rolling farmland. The following hypotheses can be used to explain the differences between these spectra. (1) For wavelengths short compared to the fetch over the new terrain, spectral densities are in equilibrium with the new terrain. (2) For wavelengths long compared to this fetch, spectral densities remain unchanged if the ground is horizontal. If the flow is over a steep hill, the low-frequency structure is modified by distortion of the mean flow, with the longitudinal component losing energy relative to the lateral and vertical components. Because vertical-velocity spectra contain relatively less low-frequency energy than horizontal-velocity spectra, energetic vertical-velocity fluctuations tend to be in equilibrium with local terrain.

Panofsky, H.A.; Larko, D.; Lipschutz, R.; Stone, G.

1981-01-01

291

Electromagnetic fuel injection valve  

SciTech Connect

An electromagnetic fuel injection valve is described comprising: (a) a housing made of a magnetic material; (b) a valve which opens and closes a fuel injection port that is hydraulically connected to the interior of the housing; (c) a moving core which drives the valve; (d) a fuel guide member which consists of a large diameter portion that is secured to the housing on the side opposite to the fuel injection port. A stationary core extends from the large diameter portion to protrude into the housing. A connection portion extends from the large diameter portion to protrude toward the outer side of the housing, and a penetration path extends from the protruding end of the stationary core to the protruding end of the connection portion; (e) an electromagnetic coil disposed in an annular space defined by the outer periphery of the stationary core and the inner periphery of the housing; (f) a tubular member which is disposed in the penetration path and which has openings at its both ends; and (g) sealing means which hydraulically seals the area between the outer periphery of the tubular member and the inner periphery of the penetration path at an end portion on the side of the fuel injection port of the tubular member.

Soma, M.; Atago, T.; Kido, T.

1986-12-02

292

THE SPECTRA OF THE DOUBLY AND TRIPLY IONIZED RARE EARTHS  

Microsoft Academic Search

The present status of the knowledge of the structure of the spectra of ; the doubly and triply ionized spectra of the rare earths is derived partly from ; experimental data of the emission spectra of the free ions which provide the ; energy level scheme in great detail but are difficuit and laborious to analyze. ; For the lower

G. H. Dieke; H. M. Crosswhite

1963-01-01

293

Electromagnetic direct implicit PIC simulation  

SciTech Connect

Interesting modelling of intense electron flow has been done with implicit particle-in-cell simulation codes. In this report, the direct implicit PIC simulation approach is applied to simulations that include full electromagnetic fields. The resulting algorithm offers advantages relative to moment implicit electromagnetic algorithms and may help in our quest for robust and simpler implicit codes.

Langdon, A.B.

1983-03-29

294

Electromagnetic forces in deformable continua  

Microsoft Academic Search

The main objective in the reported investigation is related to the determination of the interaction of the stress-strain field with the electromagnetic field in deformable bodies. The electromagnetic fields exert forces and torques on the induced sources in the matter and cause the latter to move and deform. Such interactions are considered for materials which can be polarized and magnetized,

Y.-H. Pao

1978-01-01

295

Electromagnetic Navigation during Flexible Bronchoscopy  

Microsoft Academic Search

Background: Flexible bronchoscopy is routinely utilized in the diagnosis and treatment of various lung diseases. Nondiagnostic bronchoscopy leads to more invasive interventions, such as transthoracic needle aspiration, mediastinoscopy or even thoracotomy. Electromagnetic navigation is a novel technology that facilitates approaching peripheral lung lesions, which are difficult to sample by conventional means. The navigation system involves creating an electromagnetic field around

Yehuda Schwarz; Atul C. Mehta; Armin Ernst; Felix Herth; Ahuva Engel; Doron Besser; Heinrich D. Becker

2003-01-01

296

Electromagnetic field effects in explosives  

Microsoft Academic Search

Present and previous research on the effects of electromagnetic fields on the initiation and detonation of explosives and the electromagnetic properties of explosives are reviewed. Among the topics related to detonating explosives are: measurements of conductivity; enhancement of performance; and control of initiation and growth of reaction. Hayes...()^1 showed a strong correlation of peak electrical conductivity with carbon content of

Douglas Tasker

2009-01-01

297

Health hazards and electromagnetic fields  

Microsoft Academic Search

Biological rhythms, physical wellbeing and mental states are dependent on our electrical brainwave system interacting with the extremely weak electromagnetic fields generated by the Earth's telluric and Cosmic radiations. In a single generation, since the evolution of humankind over millions of years, we are exposed to a wide range of powerful, artificially generated electromagnetic radiation which adversely affects the subtle

T. Saunders

2003-01-01

298

The Electromagnetic Spectrum: Infrared Waves  

NSDL National Science Digital Library

This webpage, part of a NASA site on the electromagnetic spectrum, presents information on infrared light. An explanation of how objects emit infrared is provided, along with a diagram of the electromagnetic spectrum. The site contains a number of photos made with infrared light.

2007-06-24

299

Electromagnetic studies in geothermal regions  

Microsoft Academic Search

During the past 25 yr, nearly all available electromagnetic and geoelectric techniques have been tested for their usefulness in geothermal exploration and exploitation. Dipole-dipole profiling, audiomagnetotellurics and controlled source electromagnetic methods are examples of those which have proven to be rather efficient for geothermal exploration. From the hundreds of field surveys which have been performed in many geothermal regions of

A. Berktold

1983-01-01

300

Exploration of the Electromagnetic Environment  

ERIC Educational Resources Information Center

|The electromagnetic environment is composed of electric and magnetic fields which result from man-made and natural sources. An elementary experiment is described to explore the electromagnetic environment by measuring electric fields in the frequency range from approximately equal to 10 to 24 000 Hz. The equipment required to conduct the…

Fullekrug, M.

2009-01-01

301

Planarity Criteria in Electromagnetic Topology.  

National Technical Information Service (NTIS)

The principal tool of the electromagnetic topologist is the interaction sequence diagram (ISD), which is the dual graph of the electromagnetic topology (EMT) of a system. One of the problems of working with the ISD is its complex appearance, in part due t...

R. S. Noss

1984-01-01

302

Planarity criteria in electromagnetic topology  

Microsoft Academic Search

The principal tool of the electromagnetic topologist is the interaction sequence diagram (ISD), which is the dual graph of the electromagnetic topology (EMT) of a system. One of the problems of working with the ISD is its complex appearance, in part due to multiple crossings of edges. This report presents some necessary and sufficient conditions for a graph to be

R. S. Noss

1984-01-01

303

Influence of steel casings on electromagnetic signals  

SciTech Connect

Most wells in oil fields are cased with metal. The feasibility of measuring low-frequency magnetic fields through such steel-cased wells is of great interest for monitoring fluid movement during production. The authors report on experimental and modeling results regarding the effect of steel casing on electromagnetic signals transmitted through them. This effect includes the attenuation and phase shift of a signal diffusing through the casing wall. Sample casings are studied under low field strength in the linear regime where the casing's electrical properties are independent of the applied signals. Frequency spectra are measured for transverse-electric and transverse-magnetic polarizations from 0.1 Hz to 1 kHz. Numerical models, developed to simulate the casing response, match the experimental data very well. Finally, studies of the effects of the earth's magnetic field and casing remnant magnetization show that these steady biases do not affect the ac signal detection.

Wu, X.; Habashy, T.M. (Schlumberger-Doll Research, Ridgefield, CT (United States))

1994-03-01

304

Coherent spin control by electromagnetic vacuum fluctuations  

SciTech Connect

In coherent control, electromagnetic vacuum fluctuations usually cause coherence loss through irreversible spontaneous emission. However, since the dissipation via emission is essentially due to correlation of the fluctuations, when emission ends in a superposition of multiple final states, correlation between different pathways may build up if the 'which way' information is not fully resolved (i.e., the emission spectrum is broader than the transition energy range). Such correlation can be exploited for spin-flip control in a {Lambda}-type three-level system, which manifests itself as an all-optical spin echo in nonlinear optics with two orders of optical fields saved as compared with stimulated Raman processes. This finding represents a class of optical nonlinearity induced by electromagnetic vacuum fluctuations.

Wang Jing [Department of Physics, Chinese University of Hong Kong, Shatin, N.T. (Hong Kong); Department of Physics, Tsinghua University, Beijing 100084 (China); Liu Renbao [Department of Physics, Chinese University of Hong Kong, Shatin, N.T. (Hong Kong); Zhu Bangfen [Department of Physics, Tsinghua University, Beijing 100084 (China); Institute of Advanced Study, Tsinghua University, Beijing 100084 (China); Sham, L. J. [Department of Physics, University of California-San Diego, La Jolla, California 92093-0319 (United States); Steel, D. G. [H. M. Randall Laboratory of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States)

2011-05-15

305

Radiated fields from an electromagnetic pulse simulator  

NASA Astrophysics Data System (ADS)

Simulators of electromagnetic pulses allow generation within a limited time of very high-intensity fields such as those produced in a nuclear explosion. These fields can be radiated out of the test zone at a lower but nevertheless significant level; if the intensity of these fields is sufficiently high, damage to humans and electronic equipment can result. An evaluation of the potential danger of these simulator emissions requires knowledge of the amplitude, duration, and the energy of the radiated impulses. A technique is presented for calculating the fields radiated by a parallel-plane electromagnetic pulse simulator. The same method can also be applied to a rhombic type simulator. Sample numerical results are presented along with the calculations of the energy and power density and a discussion of the formation of the field in the frequency domain.

Pelletier, M.; Delisle, G. Y.; Kashyap, S.

306

Electromagnetically Induced Transparency for X Rays  

SciTech Connect

Electromagnetically induced transparency is predicted for x rays in laser-dressed neon gas. The x-ray photoabsorption cross section and polarizability near the Ne K edge are calculated using an ab initio theory suitable for optical strong-field problems. The laser wavelength is tuned close to the transition between 1s{sup -1}3s and 1s{sup -1}3p ({approx}800 nm). The minimum laser intensity required to observe electromagnetically induced transparency is of the order of 10{sup 12} W/cm{sup 2}. The ab initio results are discussed in terms of an exactly solvable three-level model. This work opens new opportunities for research with ultrafast x-ray sources.

Buth, Christian; Santra, Robin; Young, Linda [Argonne National Laboratory, Argonne, Illinois 60439 (United States)

2007-06-22

307

Commission E: Electromagnetic Noise and Interference (e) Scientific basis of noise and interference control Electromagnetic Interference Compatibility for Mobile Communication System  

Microsoft Academic Search

Electromagnetic interference with one another in space, in time and frequency and therefore the effect of EMI assumes importance. Therefore it is essential that various systems (or parts of system) coexist in the electromagnetic environment. This requires the desired signal to be separated from the interference and noise in power level and\\/or in frequency. Elementary EMC analysis can be applied

M. K Rain; Kirti Gupta; Yogita Arora

308

Atomic Spectra Bibliography Databases at NIST  

Microsoft Academic Search

In June 2006, our Atomic Spectroscopy Data Center released three new Bibliographic Databases (BD) containing references to papers with atomic data for controlled fusion research, modeling and diagnostics of astrophysical and terrestrial plasmas, and fundamental properties of electronic spectra of atoms and ions. The NIST Atomic Energy Levels and Spectra BD (http:\\/\\/physics.nist.gov\\/elevbib) [EL] is the first online version of the

A. E. Kramida

2007-01-01

309

Atomic Spectra Bibliography Databases at NIST  

Microsoft Academic Search

NIST's Atomic Spectroscopy Data Center maintains three online Bibliographic Databases (BD) containing references to papers with atomic data for controlled fusion research, modeling and diagnostics of astrophysical and terrestrial plasmas, and fundamental properties of electronic spectra of atoms and ions. The NIST Atomic Energy Levels and Spectra BD [http:\\/\\/physics.nist.gov\\/elevbib] now includes about 11500 references, mostly for years 1967--2007. The NIST

Alexander Kramida

2008-01-01

310

Electromagnetic excitation of phonons at C(001) surfaces  

NASA Astrophysics Data System (ADS)

The photon-phonon coupling at C(001)-(2 × 1) surfaces and its manifestation in far-infrared reflectance anisotropy spectra (FIR-RAS) are theoretically investigated. We solve the coupled system of equations for the electromagnetic field and lattice vibrations, described within the adiabatic bond charge model (ABCM), with the method of expansion into bulk phonon and photon modes. The calculated FIR-RAS exhibit resonances associated with zone-center surface phonons in good agreement with available HREELS experiments and predictions of vibrational modes for diamond (001)-(2 × 1) surfaces from ABCM and ab initio calculations. Interestingly, the reflectance anisotropy spectra for a C(001)-(2 × 1) surface turn out to be qualitatively different from the spectra for a Si(001)-(2 × 1) surface, reported previously.

Pérez-Sánchez, F. L.; Pérez-Rodríguez, F.

2009-09-01

311

Nucleon Electromagnetic Form Factors  

SciTech Connect

There has been much activity in the measurement of the elastic electromagnetic proton and neutron form factors in the last decade, and the quality of the data has greatly improved by performing double polarization experiments, in comparison with previous unpolarized data. Here we review the experimental data base in view of the new results for the proton, and neutron, obtained at JLab, MAMI, and MIT-Bates. The rapid evolution of phenomenological models triggered by these high-precision experiments will be discussed, including the recent progress in the determination of the valence quark generalized parton distributions of the nucleon, as well as the steady rate of improvements made in the lattice QCD calculations.

Marc Vanderhaeghen; Charles Perdrisat; Vina Punjabi

2007-10-01

312

Causal electromagnetic interaction equations  

SciTech Connect

For the electromagnetic interaction of two particles the relativistic causal quantum mechanics equations are proposed. These equations are solved for the case when the second particle moves freely. The initial wave functions are supposed to be smooth and rapidly decreasing at the infinity. This condition is important for the convergence of the integrals similar to the integrals of quantum electrodynamics. We also consider the singular initial wave functions in the particular case when the second particle mass is equal to zero. The discrete energy spectrum of the first particle wave function is defined by the initial wave function of the free-moving second particle. Choosing the initial wave functions of the free-moving second particle it is possible to obtain a practically arbitrary discrete energy spectrum.

Zinoviev, Yury M. [Steklov Mathematical Institute, Gubkin Street 8, 119991, Moscow (Russian Federation)

2011-02-15

313

Computational electronics and electromagnetics  

SciTech Connect

The Computational Electronics and Electromagnetics thrust area at Lawrence Livermore National Laboratory serves as the focal point for engineering R&D activities for developing computer-based design, analysis, and tools for theory. Key representative applications include design of particle accelerator cells and beamline components; engineering analysis and design of high-power components, photonics, and optoelectronics circuit design; EMI susceptibility analysis; and antenna synthesis. The FY-96 technology-base effort focused code development on (1) accelerator design codes; (2) 3-D massively parallel, object-oriented time-domain EM codes; (3) material models; (4) coupling and application of engineering tools for analysis and design of high-power components; (5) 3-D spectral-domain CEM tools; and (6) enhancement of laser drilling codes. Joint efforts with the Power Conversion Technologies thrust area include development of antenna systems for compact, high-performance radar, in addition to novel, compact Marx generators. 18 refs., 25 figs., 1 tab.

Shang, C. C.

1997-02-01

314

Electromagnetic propulsion for spacecraft  

NASA Astrophysics Data System (ADS)

Three electromagnetic propulsion technologies, solid propellant pulsed plasma thrusters (PPT), magnetoplasmadynamic (MPD) thrusters, and pulsed inductive thrusters (PIT) have been developed for application to auxiliary and primary spacecraft propulsion. Both the PPT and MPD thrusters have been flown in space, though only PPTs have been used on operational satellites. The performance of operational PPTs is quite poor, providing only about 8 percent efficiency at about 1000 sec specific impulse. Laboratory PPTs yielding 34 percent efficiency at 5170 sec specific impulse have been demonstrated. Laboratory MPD thrusters have been demonstrated with up to 70 percent efficiency and 7000 sec specific impulse. Recent PIT performance measurements using ammonia and hydrazine propellants are extremely encouraging, reaching 50 percent efficiency for specific impulses between 4000 and 8000 sec.

Myers, Roger M.

1993-02-01

315

From plasmon spectra of metallic to vibron spectra of dielectric nanoparticles.  

PubMed

Light interacts surprisingly differently with small particles than with bulk or gas phase materials. This can cause rare phenomena such as the occurence of a "blue moon". Spectroscopic particle phenomena of similar physical origin have also spawned countless applications ranging from remote sensing to medicine. Despite the broad interest in particle spectra, their interpretation still poses many challenges. In this Account, we discuss the challenges associated with the analysis of infrared, or vibron, extinction spectra of small dielectric particles. The comparison with the more widely studied plasmon spectra of metallic nano-particles reveals many common features. The shape, size, and architecture of particles influence the band profiles in vibron and plasmon spectra in similar ways. However, the molecular structure of dielectric particles produces infrared spectral features that are more diverse and detailed or even unique to vibron spectra. More complexity means higher information content, but that also makes the spectra more difficult to interpret. Conventional models such as classical electromagnetic theory with a continuum description of the wavelength-dependent optical constants are often no longer applicable to these spectra. In cases where accurate optical constants are not available and for ultrafine particles, where the molecular structure and quantum effects become essential, researchers must resort to molecular models for light-particle interaction that do not require the prior knowledge of optical constants. In this Account, we illustrate how vibrational exciton approaches combined with molecular dynamics simulations and solid-state density functional calculations provide a viable solution to these challenges. Molecular models reveal two important characteristics of vibron spectra of small molecularly structured particles. The band profiles in vibron spectra are largely determined by transition dipole coupling between the molecules in a particle. Below a specific particle size limit, conventional models fail. Molecular models explain many other phenomena in particle spectra, such as size, shape, and mixing effects, providing the foundation for a better understanding of the interaction of solar radiation with aerosols and clouds and for the design of dielectric nanomaterials. PMID:22738352

Preston, Thomas C; Signorell, Ruth

2012-06-27

316

Differential input topologies with immunity to electromagnetic interference  

Microsoft Academic Search

Differential input structures and their immunity to electromagnetic interference (EMI) are discussed and measured. EMI signals coupling into analog circuits can have levels of up to 40 Vpp according to recent industrial EMI specifications (6). In order to maintain circuit operation under such high disturbances several on chip modifications of standard circuitry are proposed. Low EMI levels can be partly

Fridolin Michel; Michiel Steyaert

2011-01-01

317

Interpreting Astronomical Spectra  

NASA Astrophysics Data System (ADS)

Interpreting Astronomical Spectra D. Emerson Institute for Astronomy, Department of Physics and Astronomy, The University of Edingurgh "Interpreting Astronomical Spectra" describes how physical conditions such as temperature, density and composition can be obtained from the spectra of a broad range of astronomical environments ranging from the cold interstellar medium to very hot coronal gas and from stellar atmospheres to quasars. In this book the author has succeeded in providing a coherent and integrated approach to the interpretation of astronomical spectroscopy, placing the emphasis on the physical understanding of spectrum formation rather than on instrumental considerations. MKS units and consistent symbols are employed throughout so that the fundamental ideas common to diverse environments are made clear and the importance of different temperature ranges and densities can be seen. Aimed at senior undergraduates and graduates studying physics, astronomy and astrophysics, this book will also appeal to the professional astronomer.

Emerson, D.

1996-06-01

318

Interpreting Astronomical Spectra  

NASA Astrophysics Data System (ADS)

Interpreting Astronomical Spectra D. Emerson Institute for Astronomy, Department of Physics and Astronomy, The University of Edingurgh "Interpreting Astronomical Spectra" describes how physical conditions such as temperature, density and composition can be obtained from the spectra of a broad range of astronomical environments ranging from the cold interstellar medium to very hot coronal gas and from stellar atmospheres to quasars. In this book the author has succeeded in providing a coherent and integrated approach to the interpretation of astronomical spectroscopy, placing the emphasis on the physical understanding of spectrum formation rather than on instrumental considerations. MKS units and consistent symbols are employed throughout so that the fundamental ideas common to diverse environments are made clear and the importance of different temperature ranges and densities can be seen. Aimed at senior undergraduates and graduates studying physics, astronomy and astrophysics, this book will also appeal to the professional astronomer.

Emerson, D.

1999-03-01

319

Electromagnetically induced self-imaging  

NASA Astrophysics Data System (ADS)

We study the self-imaging and image-transforming properties of a probe field in a cold atomic medium with electromagnetically induced transparency (EIT). Due to the similarities between the gradient-index medium and the inhomogeneous index distribution of an EIT medium under the conditions of a negative probe detuning and a Gaussian control field, we find based on analytical investigations that there exists a kind of electromagnetically induced self-imaging phenomenon in cold atomic media. Numerical simulations clearly show that electromagnetically induced self-imaging is observable and controllable.

Cheng, Jing; Han, Shensheng

2007-05-01

320

Comparison between electroglottography and electromagnetic glottography.  

PubMed

Newly developed glottographic sensors, utilizing high-frequency propagating electromagnetic waves, were compared to a well-established electroglottographic device. The comparison was made on four male subjects under different phonation conditions, including three levels of vocal fold adduction (normal, breathy, and pressed), three different registers (falsetto, chest, and fry), and two different pitches. Agreement between the sensors was always found for the glottal closure event, but for the general wave shape the agreement was better for falsetto and breathy voice than for pressed voice and vocal fry. Differences are attributed to the field patterns of the devices. Whereas the electroglottographic device can operate only in a conduction mode, the electromagnetic device can operate in either the forward scattering (diffraction) mode or in the backward scattering (reflection) mode. Results of our tests favor the diffraction mode because a more favorable angle imposed on receiving the scattered (reflected) signal did not improve the signal strength. Several observations are made on the uses of the electromagnetic sensors for operation without skin contact and possibly in an array configuration for improved spatial resolution within the glottis. PMID:10641666

Titze, I R; Story, B H; Burnett, G C; Holzrichter, J F; Ng, L C; Lea, W A

2000-01-01

321

Natural electromagnetic ULF noise due to fluctuations of ionospheric currents  

NASA Astrophysics Data System (ADS)

An origin of natural electromagnetic noise observed on the ground surface in the frequency range 10-4-10-2 Hz was examined. Following a recent paper by Surkov and Hayakawa (2007), a flicker noise or 1/f noise, provided by random currents, is treated as a possible source of the ULF electromagnetic noise. In contrast to the cited paper, MHD wave incident on the ionosphere and neutral gas flow in the altitude range of conducting E layer of the ionosphere are considered to be a candidate mechanism for random current fluctuations, which in turn produce random electromagnetic fluctuations in the atmosphere. The main emphasis is on the flicker noise provided by the wind-driven ionospheric currents, which is assumed to be steady, uniform, and isotropic random fields inside the ionosphere. A correlation radius of random ionospheric fields is supposed to be controlled by neutral gas transfer and by acoustic/gravity wave propagation inside the E layer. A correlation matrix and power spectra of the random electromagnetic fields on the ground surface were calculated. The predicted spectral index of the power spectrum of the ULF magnetic noise was found to be 3, which is consistent with ground-based observations. The experimental data were demonstrated to be sandwiched between two theoretical lines, which correspond to daytime and nighttime ionospheric parameters.

Surkov, V. V.; Hayakawa, M.

2008-11-01

322

Bobbing and kicks in electromagnetism and gravity  

SciTech Connect

We study systems analogous to binary black holes with spin in order to gain some insight into the origin and nature of 'bobbing' motion and 'kicks' that occur in this system. Our basic tool is a general formalism for describing the motion of extended test bodies in an external electromagnetic field in curved spacetime and possibly subject to other forces. We first show that bobbing of exactly the type as observed in numerical simulations of the binary black hole system occurs in a simple system consisting of two spinning balls connected by an elastic band in flat spacetime. This bobbing may be understood as arising from the difference between a spinning body's 'lab frame centroid' and its true center of mass, and is purely 'kinematical' in the sense that it will appear regardless of the forces holding two spinning bodies in orbit. Next, we develop precise rules for relating the motion of charged bodies in a stationary external electromagnetic field in flat spacetime with the motion of bodies in a weakly curved stationary spacetime. We then consider the system consisting of two orbiting charges with magnetic dipole moment and spin at a level of approximation corresponding to 1.5 post-Newtonian order. Here we find that considerable amounts of momentum are exchanged between the bodies and the electromagnetic field; however, the bodies store this momentum entirely as ''hidden'' mechanical momentum, so that the interchange does not give rise to any net bobbing. The net bobbing that does occur is due solely to the kinematical spin effect, and we therefore argue that the net bobbing of the electromagnetic binary is not associated with possible kicks. We believe that this conclusion holds in the gravitational case as well.

Gralla, Samuel E.; Harte, Abraham I.; Wald, Robert M. [Enrico Fermi Institute and Department of Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, Illinois 60637 (United States)

2010-05-15

323

Bobbing and kicks in electromagnetism and gravity  

NASA Astrophysics Data System (ADS)

We study systems analogous to binary black holes with spin in order to gain some insight into the origin and nature of “bobbing” motion and “kicks” that occur in this system. Our basic tool is a general formalism for describing the motion of extended test bodies in an external electromagnetic field in curved spacetime and possibly subject to other forces. We first show that bobbing of exactly the type as observed in numerical simulations of the binary black hole system occurs in a simple system consisting of two spinning balls connected by an elastic band in flat spacetime. This bobbing may be understood as arising from the difference between a spinning body’s “lab frame centroid” and its true center of mass, and is purely “kinematical” in the sense that it will appear regardless of the forces holding two spinning bodies in orbit. Next, we develop precise rules for relating the motion of charged bodies in a stationary external electromagnetic field in flat spacetime with the motion of bodies in a weakly curved stationary spacetime. We then consider the system consisting of two orbiting charges with magnetic dipole moment and spin at a level of approximation corresponding to 1.5 post-Newtonian order. Here we find that considerable amounts of momentum are exchanged between the bodies and the electromagnetic field; however, the bodies store this momentum entirely as “hidden” mechanical momentum, so that the interchange does not give rise to any net bobbing. The net bobbing that does occur is due solely to the kinematical spin effect, and we therefore argue that the net bobbing of the electromagnetic binary is not associated with possible kicks. We believe that this conclusion holds in the gravitational case as well.

Gralla, Samuel E.; Harte, Abraham I.; Wald, Robert M.

2010-05-01

324

Nonlinear fan instability of electromagnetic waves  

SciTech Connect

This paper studies the linear and nonlinear stages of the fan instability, considering electromagnetic waves of the whistler frequency range interacting resonantly with energetic electron fluxes in magnetized plasmas. The main attention is paid to determine the wave-particle interaction processes that can lead to the excitation of intense electromagnetic waves by nonequilibrium particle distributions involving suprathermal tails, and to explain under what conditions and through what mechanisms they can occur, develop, and saturate. This paper presents and discusses two main processes: (i) the linear fan instability and (ii) the nonlinear process of dynamical resonance merging, which can significantly amplify the energy carried by linearly destabilized waves after they saturate due to particle trapping. This study consists of (i) determining analytically and numerically, for parameters typical of space and laboratory plasmas, the linear growth rates of whistlers excited by suprathermal particle fluxes through the fan instability, as well as the corresponding thresholds and the physical conditions at which the instability can appear, (ii) building a theoretical self-consistent 3D model and a related numerical code for describing the nonlinear evolution of the wave-particle system, and (iii) performing numerical simulations to reveal and characterize the nonlinear amplification process at work, its conditions of development, and its consequences, notably in terms of electromagnetic wave radiation. The simulations show that when the waves have reached sufficient energy levels owing to the linear fan instability, they saturate by trapping particles and due to the complex dynamics of these particles in the electromagnetic fields, the resonant velocities' domains of the waves overlap and merge, meanwhile a strong increase of the wave energy occurs.

Krafft, C. [Laboratoire de Physique des Plasmas, Ecole Polytechnique, 91128 Palaiseau Cedex (France) and University Paris Sud, 91405 Orsay Cedex (France); Volokitin, A. [Space Research Institute (IKI), 117997, 84/32 Profsoyuznaya Str., Moscow (Russian Federation)

2010-10-15

325

Reconstruction of the global lightning distribution from ELF electromagnetic background signals  

Microsoft Academic Search

The global lightning distribution has been obtained for the first time as the result of an inverse problem for the natural extremely low-frequency (ELF) electromagnetic background signals measured simultaneously at three stations: Lekhta (Karelia, Russia), Moshiri (Hokkaido, Japan), and West Greenwich (Rhode Island, USA). We employed a two-step technique consisting of: (1) inversion of ELF field spectra to a source

A. V. Shvets; M. Hayakawa; M. Sekiguchi; Y. Ando

2009-01-01

326

Quantitative experimental determination of scattering and absorption cross-section spectra of individual optical metallic nanoantennas.  

PubMed

Antennas convert propagating radiation to localized electromagnetic energy and to heat. To unambiguously separate between these two aspects, one needs to quantitatively determine the antenna scattering and absorption cross-section spectra. By using a spatial modulation technique combined with a common-path interferometer and lithographically fabricated individual gold nanoantennas, we experimentally determine the scattering and absorption cross-section spectra of different optical antennas simultaneously and quantitatively for the first time. PMID:23368203

Husnik, Martin; Linden, Stefan; Diehl, Richard; Niegemann, Jens; Busch, Kurt; Wegener, Martin

2012-12-04

327

Electromagnetic Compatibility in Aerospace Vehicles.  

National Technical Information Service (NTIS)

Electromagnetic compatibility in aerospace vehicles which requires careful consideration because of the generally high packing density of electronic equipment aboard aircraft or spacecraft, the complex cable hardness and the required reliability margins. ...

O. B. M. Pietersen

1983-01-01

328

Materials for electromagnetic interference shielding  

Microsoft Academic Search

Materials for the electromagnetic interference (EMI) shielding of electronics and radiation sources are reviewed, with emphasis\\u000a on composite materials and resilient EMI gasket materials, which shield mainly by reflection of the radiation at a high frequency.

D. D. L. Chung

2000-01-01

329

Surface Vibration Electromagnetic Speech Sensor.  

National Technical Information Service (NTIS)

Abstract-As researchers continue to improve speech in noisy II environments, more interest is being placed on sensors with modalities that can be fused with traditional acoustic sensors. The standard literature has shown that electromagnetic sensors can b...

E. F. Greneker I. Chuckpaiwong J. L. Geisheimer S. A. Billington

2002-01-01

330

Sommerfeld Integrals and Electromagnetic Fields.  

National Technical Information Service (NTIS)

The complete electromagnetic fields for both elementary electric and magnetic dipoles are listed for both horizontal and vertical orientations of the dipoles. All combinations of dipole and field point locations above or below the boundary between two con...

T. W. H. Caffey

1988-01-01

331

Spectra of Ternary Alloys  

Microsoft Academic Search

The vibrational frequency-dsitribution spectra of the random one-dimensional ternary alloy AcB1-cC are accurately predicted for the first time by a statistical theory of small clusters embedded in a coherent-potential-approximation effective medium. The theory can be applied practically to real three-dimensional alloys.

Charles W. Myles; John D. Dow

1979-01-01

332

Moderation of neutron spectra  

SciTech Connect

Most of the accelerators that produce the various microenergetic neutron sources required for low-energy neutron dosimetry studies have been shut down. One alternative to accelerator-produced sources is the use of fission neutron or ({alpha},n) sources with unique neutron spectra. The problem with this solution is that maintenance of these sources is impractical. To help overcome this impracticality, the authors propose the use of moderating materials to produce a variety of spectra using a minimum number of sources. In the study, they performed Monte Carlo transport calculations under the following conditions: transporting neutrons from bare {sup 252}Cf or {sup 241}Am-Be sources from the center of various-sized spheres; tallying neutron spectra at 50 cm from the source. Of the twelve different moderating materials they studied, they found pure copper to be an ideal moderator. In this paper, they present flux-weighted energies, neutron spectra, and dose information for both {sup 252}Cf and {sup 241}Am-Be sources in bare and six-moderator configurations.

Hsu, H.H.; Chen, J. [Los Alamos National Lab., NM (United States). Health Physics Measurements Group

1997-05-01

333

Self-dual electromagnetic fields  

NASA Astrophysics Data System (ADS)

We demonstrate the utility of self-dual fields in electrodynamics. Stable configurations of free electromagnetic fields can be represented as superpositions of standing waves, each possessing zero Poynting vector and zero orbital angular momentum. The standing waves are themselves superpositions of self-dual and anti-self-dual solutions. The idea of self-duality provides additional insights into the geometrical and spectral properties of stable electromagnetic configurations, such as those responsible for the formation of ball lightning.

Chubykalo, Andrew E.; Espinoza, Augusto; Kosyakov, B. P.

2010-08-01

334

Electromagnetic Effects in SDF Explosions  

Microsoft Academic Search

The notion of high ion and electron concentrations in the detonation of aluminized explosive mixtures has aroused some interest in electro-magnetic effects that the SDF charges might generate when detonated. Motivated by this interest we have started to investigate whether significant electro-magnetic effects show up in our small-scale experiments. However, the design of instrumentation for this purpose is far from

H Reichenbach; P Neuwald; A L Kuhl

2010-01-01

335

Electromagnetic holographic imaging of bioimpedance  

NASA Astrophysics Data System (ADS)

The electromagnetic bioimpedance method has successfully measured the very subtle conductivity changes associated with brain edema and prostate tumor. This method provides noninvasive measurements using non-ionizing magnetic fields applied with a small coil that avoids the use of contact electrodes. This paper introduces results from combining a holographic signal processing algorithm and a low power coil system that helps provide the 3D image of impedance contrast that should make the noninvasive electromagnetic bioimpedance method useful in health care.

Smith, Dexter G.; Ko, Harvey W.; Lee, Benjamin R.; Partin, Alan W.

1998-05-01

336

The Nature of Electromagnetic Radiation  

NSDL National Science Digital Library

This web site is a reference page on electromagnetic radiation. It discusses the spectrum of light and both the wave and quantum nature of radiation. Also included are descriptions of the physics and applications of the different frequency bands, from gamma rays through radio waves, plus links to interactive Java simulations on the topic. See Related Materials on this page for a simpler student tutorial by the same authors on the topic of electromagnetic radiation.

Davidson, Michael; Abramowitz, Mortimer; Fellers, Thomas J.

2008-08-21

337

Time Reversal of Electromagnetic Waves  

Microsoft Academic Search

We report the first experimental demonstration of time-reversal focusing with electromagnetic waves. An antenna transmits a 1-mus electromagnetic pulse at a central frequency of 2.45GHz in a high-Q cavity. Another antenna records the strongly reverberated signal. The time-reversed wave is built and transmitted back by the same antenna acting now as a time-reversal mirror. The wave is found to converge

G. Lerosey; J. de Rosny; A. Tourin; A. Derode; G. Montaldo; M. Fink

2004-01-01

338

Electromagnetic methods in applied geophysics  

NASA Astrophysics Data System (ADS)

Review of promising new research developments dealing with electromagnetic methods in applied geophysics. Slow, steady progress of numerical modeling is seen in traditional low-frequency CW technology. Cryogenic coil systems are viewed as the major development in this area. In the newer area of transient applications, the most impressive results are coming from the use of seismic processing with earth-penetrating radar and the rapid development of transient electromagnetic equipment, theory, and experience.

Vozoff, K.

1980-09-01

339

Polarimetry of electromagnetic materials  

NASA Astrophysics Data System (ADS)

The goal of the polarimetry of electromagnetic solids is the thorough determinations of not only the linear and circular birefringences (LB an CB) but also the linear and circular dichroisms (LD and CD). Needless to say, measurements of circular phenomena are exceedingly more difficult than those of linear ones. For instance, the long period of 170 years elapsed from the discovery of CB by Arago in 1811 until the development of high accuracy universal polarimeter (HAUP) by Kobayashi in 1983, when the first perfect measurements of CB of solids became possible. Subsequent to the appearance of the HAUP method, attempts of extending HAUP theory to be applicable to CD measurements were followed by Moxon and Renshaw, and Dijkstra, Kremers, and Meekes by using Jones matrix calculus. However, their measurements to NiSO4 multiplied by 6H2O were not fully satisfactory. We completed afresh the theory of the extended HAUP and measured successfully LD of a high temperature superconductor Bi2Sr2CaCu2O8. An important fact was clarified; the extended HAUP theory indicates that CD can be obtained exclusively through accurate measurements of (theta) 0, a characteristic angle introduced in the original HAUP method. It means that there would be no ways for measuring CD of solids except for the HAUP method. Preliminary results of applying our theory to silver thiogallate are shown finally.

Asahi, Toru; Osaka, Tetsuya; Kobayashi, Jinzo

2001-07-01

340

SOLAR NANTENNA ELECTROMAGNETIC COLLECTORS  

SciTech Connect

This research explores a new efficient approach for producing electricity from the abundant energy of the sun. A nanoantenna electromagnetic collector (NEC) has been designed, prototyped, and tested. Proof of concept has been validated. The device targets mid-infrared wavelengths where conventional photovoltaic (PV) solar cells do not respond but is abundant in solar energy. The initial concept of designing NEC antennas was based on scaling of radio frequency antenna theory. This approach has proven unsuccessful by many due to not fully understanding and accounting for the optical behavior of materials in the THz region. Also until recent years the nanofabrication methods were not available to fabricate the optical antenna elements. We have addressed and overcome both technology barriers. Several factors were critical in successful implementation of NEC including: 1) frequency-dependent modeling of antenna elements, 2) selection of materials with proper THz properties and 3) novel manufacturing methods that enable economical large-scale manufacturing. The work represents an important step toward the ultimate realization of a low-cost device that will collect as well as convert this radiation into electricity, which will lead to a wide spectrum, high conversion efficiency, and low cost solution to complement conventional PVs.

Steven D. Novack; Dale K. Kotter; Dennis Slafer; Patrick Pinhero

2008-08-01

341

Structures, systems and methods for harvesting energy from electromagnetic radiation  

DOEpatents

Methods, devices and systems for harvesting energy from electromagnetic radiation are provided including harvesting energy from electromagnetic radiation. In one embodiment, a device includes a substrate and one or more resonance elements disposed in or on the substrate. The resonance elements are configured to have a resonant frequency, for example, in at least one of the infrared, near-infrared and visible light spectra. A layer of conductive material may be disposed over a portion of the substrate to form a ground plane. An optical resonance gap or stand-off layer may be formed between the resonance elements and the ground plane. The optical resonance gap extends a distance between the resonance elements and the layer of conductive material approximately one-quarter wavelength of a wavelength of the at least one resonance element's resonant frequency. At least one energy transfer element may be associated with the at least one resonance element.

Novack, Steven D. (Idaho Falls, ID); Kotter, Dale K. (Shelley, ID); Pinhero, Patrick J. (Columbia, MO)

2011-12-06

342

Electromagnetic interference shielding effectiveness of electroless Cu-plated PET fabrics  

Microsoft Academic Search

In order to develop the high quality electromagnetic interference (EMI) shielding textiles for protective clothing, polyester fabrics were electroless copper-plated. Effects of pretreatment conditions such as scouring, etching, and catalyzation on electromagnetic interference shielding effectiveness (EMISE) and physical properties of treated fabrics were investigated.High EMISE of fabrics over the wide range of frequency level were obtained when fabrics were scoured

Eun Gyeong Han; Eun Ae Kim; Kyung Wha Oh

2001-01-01

343

Metamaterial analog of quantum interference: From electromagnetically induced transparency to absorption  

Microsoft Academic Search

With a metamaterial structure, the phenomenology observed in quantum electromagnetically induced transparency is reproduced. Through the parametric comparison between quantum and classical systems, the physical mechanism of this novel phenomenon has been explained directly in our analysis. In addition, we use another metamaterial structure to mimic a tripod four-level atom and reveal the analog of electromagnetically induced absorption. Our theoretical

Y. Sun; W. Tan; L. Liang; H.-T. Jiang; Z.-G. Wang; F.-Q. Liu; H. Chen

2012-01-01

344

Some Observable Effects of the Quantum-Mechanical Fluctuations of the Electromagnetic Field  

Microsoft Academic Search

An intuitive explanation is given for the electromagnetic shift of energy levels by calculating the mean square amplitude of oscillation of an electron coupled to the zero-point fluctuations of the electromagnetic field. The resulting disturbance of the charge and current density of the electron gives rise to various observable effects which can be estimated in a simple classical fashion. The

Theodore A. Welton

1948-01-01

345

Multispectral processing without spectra  

NASA Astrophysics Data System (ADS)

It is often the case that multiplications of whole spectra, component by component, must be carried out, for example when light reflects from or is transmitted through materials. This leads to particularly taxing calculations, especially in spectrally based ray tracing or radiosity in graphics, making a full-spectrum method prohibitively expensive. Nevertheless, using full spectra is attractive because of the many important phenomena that can be modeled only by using all the physics at hand. We apply to the task of spectral multiplication a method previously used in modeling RGB-based light propagation. We show that we can often multiply spectra without carrying out spectral multiplication. In previous work J. Opt. Soc. Am. A 11 , 1553 (1994) we developed a method called spectral sharpening, which took camera RGBs to a special sharp basis that was designed to render illuminant change simple to model. Specifically, in the new basis, one can effectively model illuminant change by using a diagonal matrix rather than the 33 linear transform that results from a three-component finite-dimensional model G. Healey and D. Slater, J. Opt. Soc. Am. A 11 , 3003 (1994). We apply this idea of sharpening to the set of principal components vectors derived from a representative set of spectra that might reasonably be encountered in a given application. With respect to the sharp spectral basis, we show that spectral multiplications can be modeled as the multiplication of the basis coefficients. These new product coefficients applied to the sharp basis serve to accurately reconstruct the spectral product. Although the method is quite general, we show how to use spectral modeling by taking advantage of metameric surfaces, ones that match under one light but not another, for tasks such as volume rendering. The use of metamers allows a user to pick out or merge different volume structures in real time simply by changing the lighting. 2003 Optical Society of America

Drew, Mark S.; Finlayson, Graham D.

2003-07-01

346

Multispectral processing without spectra.  

PubMed

It is often the case that multiplications of whole spectra, component by component, must be carried out,for example when light reflects from or is transmitted through materials. This leads to particularly taxing calculations, especially in spectrally based ray tracing or radiosity in graphics, making a full-spectrum method prohibitively expensive. Nevertheless, using full spectra is attractive because of the many important phenomena that can be modeled only by using all the physics at hand. We apply to the task of spectral multiplication a method previously used in modeling RGB-based light propagation. We show that we can often multiply spectra without carrying out spectral multiplication. In previous work [J. Opt. Soc. Am. A 11, 1553 (1994)] we developed a method called spectral sharpening, which took camera RGBs to a special sharp basis that was designed to render illuminant change simple to model. Specifically, in the new basis, one can effectively model illuminant change by using a diagonal matrix rather than the 3 x 3 linear transform that results from a three-component finite-dimensional model [G. Healey and D. Slater, J. Opt. Soc. Am. A 11, 3003 (1994)]. We apply this idea of sharpening to the set of principal components vectors derived from a representative set of spectra that might reasonably be encountered in a given application. With respect to the sharp spectral basis, we show that spectral multiplications can be modeled as the multiplication of the basis coefficients. These new product coefficients applied to the sharp basis serve to accurately reconstruct the spectral product. Although the method is quite general, we show how to use spectral modeling by taking advantage of metameric surfaces, ones that match under one light but not another, for tasks such as volume rendering. The use of metamers allows a user to pick out or merge different volume structures in real time simply by changing the lighting. PMID:12868625

Drew, Mark S; Finlayson, Graham D

2003-07-01

347

Martian neutron leakage spectra  

SciTech Connect

Energy spectra of Martian leakage neutrons are calculated by a high-energy nucleon-meson transport code using a Monte Carlo technique and a one-dimensional diffusion accelerated neutral-particle transport code, which solves the Boltzmann equation. Four series of calculations were made to simulate (1) a uniform surface layer containing various amounts of H/sub 2/O, (2) different burial depths of a 50% H/sub 2/O layer underneath a 1% H/sub 2/O layer, (3) changing atmospheric pressure, and (4) a thick CO/sub 2/ ice sheet overlying a ''dirty'' water ice sheet. We found that all calculated spectra at energies less than about 1000 eV could be fitted by a superposition of thermal and epithermal functions having four free parameters. Two of these parameters, the thermal and epithermal amplitudes, were found to vary systematically over ranges exceeding 1 order of magnitude and to specify uniquely the configuration in each of the series. We conclude that measurements of leakage neutron spectra should allow determination of the hydrogen content of surface layers buried to depths up to about 100 g/cm/sup 2/ and determination of the thickness of a polar dry ice cap up to thicknesses of about 250 g/cm/sup 2/. Variations of these parameters were also shown to depend on the composition of the assumed surface layers through the average atomic mass and the macroscopic scattering and absorption cross sections. copyright American Geophysical Union 1988

Drake, D.M.; Feldman, W.C.; Jakosky, B.M.

1988-06-10

348

Martian neutron leakage spectra  

NASA Astrophysics Data System (ADS)

A high-energy nucleon-meson transport code is used to calculate energy spectra of Martian leakage neutrons. Four calculations are used to simulate a uniform surface layer containing various amounts of water, different burial depths of a 50 percent water layer underneath a 1 percent water layer, changing atmospheric pressure, and a thick carbon dioxide ice sheet overlying a "dirty" water ice sheet. Calculated spectra at energies less than about 1000 eV were fitted by a superposition of thermal and epithermal functions having four free parameters, two of which (thermal and epithermal amplitudes) were found to vary systematically and to specify uniquely the configuration in each of the series. Parameter variations depend on the composition of the assumed surface layers through the average atomic mass and the macroscopic scattering and absorption cross sections. It is concluded that measurements of leakage neutron spectra should allow determination of the hydrogen content of surface layers buried to depths up to about 100 g/sq. cm and determination of the thickness of a polar dry ice cap up to a thickness of about 250 g/sq. cm.

Drake, D. M.; Feldman, W. C.; Jakosky, B. M.

1988-06-01

349

Electromagnetic potentials without gauge transformations  

NASA Astrophysics Data System (ADS)

In this paper, we show that the use of the Helmholtz theorem enables the derivation of uniquely determined electromagnetic potentials without the necessity of using gauge transformation. We show that the electromagnetic field comprises two components, one of which is characterized by instantaneous action at a distance, whereas the other propagates in retarded form with the velocity of light. In our attempt to show the superiority of the new proposed method to the standard one, we argue that the action-at-a-distance components cannot be considered as a drawback of our method, because the recommended procedure for eliminating the action at a distance in the Coulomb gauge leads to theoretical subtleties that allow us to say that the needed gauge transformation is not guaranteed. One of the theoretical consequences of this new definition is that, in addition to the electric E and magnetic B fields, the electromagnetic potentials are real physical quantities. We show that this property of the electromagnetic potentials in quantum mechanics is also a property of the electromagnetic potentials in classical electrodynamics.

Chubykalo, A.; Espinoza, A.; Alvarado Flores, R.

2011-07-01

350

High performance electromagnetic simulation tools  

NASA Astrophysics Data System (ADS)

Army Research Office Grant #DAAH04-93-G-0453 has supported the purchase of 24 additional compute nodes that were installed in the Intel iPsC/860 hypercube at the Univesity Of Kentucky (UK), rendering a 32-node multiprocessor. This facility has allowed the investigators to explore and extend the boundaries of electromagnetic simulation for important areas of defense concerns including microwave monolithic integrated circuit (MMIC) design/analysis and electromagnetic materials research and development. The iPSC/860 has also provided an ideal platform for MMIC circuit simulations. A number of parallel methods based on direct time-domain solutions of Maxwell's equations have been developed on the iPSC/860, including a parallel finite-difference time-domain (FDTD) algorithm, and a parallel planar generalized Yee-algorithm (PGY). The iPSC/860 has also provided an ideal platform on which to develop a 'virtual laboratory' to numerically analyze, scientifically study and develop new types of materials with beneficial electromagnetic properties. These materials simulations are capable of assembling hundreds of microscopic inclusions from which an electromagnetic full-wave solution will be obtained in toto. This powerful simulation tool has enabled research of the full-wave analysis of complex multicomponent MMIC devices and the electromagnetic properties of many types of materials to be performed numerically rather than strictly in the laboratory.

Gedney, Stephen D.; Whites, Keith W.

1994-10-01

351

Possible Ionospheric Electromagnetic Perturbations Induced by the Ms7.1 Yushu Earthquake  

NASA Astrophysics Data System (ADS)

The power spectrum density (PSD) of magnetic field in the ELF/VLF band recorded by the experiment IMSC onboard the DEMETER satellite were used to study the Ms7.1 Yushu earthquake taking place on April 13, 2010 in China. The results indicate that possible ionospheric electromagnetic perturbations occurring 4 days before the earthquake in the frequency range [370-897 Hz]. Along the orbit 30880_up, which passed over the epicenter area on 9 April, enhanced PSD value of magnetic field at 410 Hz was detected both over the epicentral area and its conjugate point in the southern hemisphere. While on revisited orbits during other days (before and after the earthquake) the magnetic field spectra remained at a relatively low level. In order to be sure that the electromagnetic disturbances were induced by this Yushu earthquake, relative variations of the magnetic field in the ELF/VLF range [370-897 Hz] were calculated and compared with the normal background during 3 years (2007, 2008 and 2009) in the time interval from Jan. 1st to Apr. 30 and in the area [23°N-43°N, 86°E-106°E]. The results show that the normal level of magnetic field in this area is relatively low (~10-7 nT2/Hz), but a large increase occurred from Apr. 1st to Apr. 14 which exceeds 5?b. After the earthquake, the magnetic field in the ELF/VLF range gradually decreased. In order to exclude the influence of geomagnetic field activity, we selected only the data recorded during magnetically quiet local night-times. In addition, artificial noises were also removed from the dataset used in the present paper. Therefore the observed perturbations were independent of geomagnetic field disturbances, and might be attributed to seismic activity.

Zhima, Zeren; Xuhui, Shen; Xuemin, Zhang; Jinbin, Cao; Jianping, Huang; Xinyan, Ouyang; Jing, Liu; Lu, Bingqing

2012-06-01

352

Electromagnetic diode based on nonlinear electromagnetically induced transparency in metamaterials  

NASA Astrophysics Data System (ADS)

We propose a scheme for subwavelength electromagnetic diode by employing the nonreciprocal electromagnetically induced transparency (EIT) in metamaterials. One-way response, with 17.36 dB transmission contrast and -4.4 dBm operating power, is conceptually demonstrated in a microwave waveguide system with asymmetric absorption and a varactor as the nonlinear medium inclusion. Such low-threshold and high-contrast transmission diode action comes from the EIT mechanism, which possesses narrower and sharper features than the Lorentz resonance. This mechanism will be useful for all-optical signal processing with advanced materials.

Sun, Yong; Tong, Yuan-wei; Xue, Chun-hua; Ding, Ya-qiong; Li, Yun-hui; Jiang, Haitao; Chen, Hong

2013-08-01

353

Synthetic spectra of CP stars compared with UVES spectra  

NASA Astrophysics Data System (ADS)

Results from spectral analyses of some HgMn stars observed with UVES at high resolution and high S/N are available on-line in the form of plots showing superimposed observed and LTE-computed spectra. The material is available on line at http://wwwuser.oat.ts.astro.it/castelli/stars.html. The ranges studied are divided into 6Å wide intervals. The plots have identifications, excitation potential of the lower level, and predicted line intensities written above the lines. Complete analyses covering the 3050 - 9500Å region have been performed for two stars, HD175640 and HR6000. The on-line plots show the quality of the agreement between observations and computations and can be used as a template for other stars of the same spectral type. For instance, HD175640 and HR6000 are excellent examples of a very overabundant Mn ([+2.4]) star and of a very overabundant Fe ([+0.7]) star, respectively.

Castelli, F.; Hubrig, S.

2008-04-01

354

Background noise spectra of global seismic stations  

SciTech Connect

Over an extended period of time station noise spectra were collected from various sources for use in estimating the detection and location performance of global networks of seismic stations. As the database of noise spectra enlarged and duplicate entries became available, an effort was mounted to more carefully select station noise spectra while discarding others. This report discusses the methodology and criteria by which the noise spectra were selected. It also identifies and illustrates the station noise spectra which survived the selection process and which currently contribute to the modeling efforts. The resulting catalog of noise statistics not only benefits those who model network performance but also those who wish to select stations on the basis of their noise level as may occur in designing networks or in selecting seismological data for analysis on the basis of station noise level. In view of the various ways by which station noise were estimated by the different contributors, it is advisable that future efforts which predict network performance have available station noise data and spectral estimation methods which are compatible with the statistics underlying seismic noise. This appropriately requires (1) averaging noise over seasonal and/or diurnal cycles, (2) averaging noise over time intervals comparable to those employed by actual detectors, and (3) using logarithmic measures of the noise.

Wada, M.M.; Claassen, J.P.

1996-08-01

355

Airborne electromagnetic measurements of sea ice thickness: methods and applications  

Microsoft Academic Search

Alfred Wegener Institute operates two helicopter-borne electromagnetic (EM) sounding devices dedicated to the measurement of sea ice thickness. With the method, level total (ice plus snow) thickness can be determined with an accuracy of ±0.1 m. However, due to the footprint of the method and due to the porosity of unconsolidated ridge keels, deformed ice thickness can be strongly underestimated.

Christian Haas; Sibylle Goebell; Stefan Hendricks; Torge Martin; Andreas Pfaffling; Carola von Saldern

356

Introduction to Eye-Opening Technology: The Electromagnetic Spectrum.  

ERIC Educational Resources Information Center

Provides classroom activities centered around how the electromagnetic spectrum yields vital insights about the evolution of the universe. Activities targeted for grade levels 6-12 illustrate the importance of light and color in space exploration. Includes a poster. (Author/SOE)

Smith, Denise; Eisenhamer, Bonnie; DeVore, Edna; Bianchi, Luciana

2003-01-01

357

Introduction to Eye-Opening Technology: The Electromagnetic Spectrum.  

ERIC Educational Resources Information Center

|Provides classroom activities centered around how the electromagnetic spectrum yields vital insights about the evolution of the universe. Activities targeted for grade levels 6-12 illustrate the importance of light and color in space exploration. Includes a poster. (Author/SOE)|

Smith, Denise; Eisenhamer, Bonnie; DeVore, Edna; Bianchi, Luciana

2003-01-01

358

Preliminary survey of the electromagnetic interference environment in hospitals  

Microsoft Academic Search

Electric field levels were predicted using a free-space propagation model, and then measured in three major hospitals in downtown Montreal. The measurements were performed using industry-standard techniques and novel broadband, omnidirectional, triaxial, electrically small (BOTES) techniques. Although the absolute values of predictions were often unreliable, they acceptably predicted the type of electromagnetic environment observed at different hospitals. Results from both

P. Boisvert; B. Segal; T. Pavlasek; S. Retfalvi; A. Sebe; P. Carons

1991-01-01

359

Effect of electromagnetic radiations on humans: A study  

Microsoft Academic Search

@gmai l.com Abstract- A complete analysis of electromagnetic radiations has been done for the electronic devices that have become a part of human life. All the devices have been studied for their maximum level of emissions and the distance at which they have minimal effect. Following these surveys a layout has been proposed for an ideal 18*15 living room such

Aakanksha Aggarwal; Abhishek Gupta

2011-01-01

360

Electromagnetic fields and public health.  

PubMed Central

A review of the literature is provided for the topic of health-related research and power frequency electromagnetic fields. Minimal evidence for concern is present on the basis of animal and plant research. General observation would accord with the implication that there is no single and manifest health effect as the result of exposure to these fields. There are persistent indications, however, that these fields have biologic activity, and consequently, there may be a deleterious component to their action, possibly in the presence of other factors. Power frequency electromagnetic field exposures are essentially ubiquitous in modern society, and their implications in the larger perspective of public health are unclear at this time. Electromagnetic fields represent a methodological obstacle for epidemiologic studies and a quandary for risk assessment; there is need for more data.

Aldrich, T E; Easterly, C E

1987-01-01

361

Electromagnetically induced transparency in an open multilevel system  

SciTech Connect

Electromagnetically induced transparency in a multilevel system is investigated in {sup 173}Yb. The level structure investigated is ''open'' in that the light that gives rise to the transparency also resonantly couples the atoms to excited states which do not exhibit electromagnetically induced transparency. The resulting reduction of transparency is investigated experimentally and theoretically. It is found that, while the transparency is poor in certain regimes, it can be made to perform arbitrarily well in the limit of a large intensity imbalance between the optical fields.

Li Tian; Lu Meiju; Weinstein, Jonathan D. [Department of Physics, University of Nevada, Reno, Nevada 89557 (United States)

2011-08-15

362

Modeling microwave electromagnetic field absorption in muscle tissues  

NASA Astrophysics Data System (ADS)

Absorption of electromagnetic energy in human tissues is an important issue with respect to the safety of low-level exposure. Simulation is a way to a better understanding of electromagnetic dosimetry. This letter presents a comparison between results obtained from a numerical simulation and experimental data of absorbed energy by a muscle. Simulation was done using a bidimensional double-scale homogenization scheme leading to the effective permittivity tensor. Experimental measurements were performed at 10 GHz on bovine muscle, 30 hours after slaughter, thanks to the open-ended rectangular waveguide method. Results show a good agreement between measurements and simulated data.

Felbacq, D.; Clerjon, S.; Damez, J. L.; Zolla, F.

2002-07-01

363

Staggered ladder spectra.  

PubMed

We exactly solve a Fokker-Planck equation by determining its eigenvalues and eigenfunctions: we construct nonlinear second-order differential operators which act as raising and lowering operators, generating ladder spectra for the odd- and even-parity states. The ladders are staggered: the odd-even separation differs from even-odd. The Fokker-Planck equation corresponds, in the limit of weak damping, to a generalized Ornstein-Uhlenbeck process where the random force depends upon position as well as time. The process describes damped stochastic acceleration, and exhibits anomalous diffusion at short times and a stationary non-Maxwellian momentum distribution. PMID:16486675

Arvedson, E; Wilkinson, M; Mehlig, B; Nakamura, K

2006-01-25

364

Action Spectra for Human Skin Cells: Estimates of the Relative Cytotoxicity of the Middle Ultraviolet, Near Ultraviolet, and Violet Regions of Sunlight on Epidermal Keratinocytes1  

Microsoft Academic Search

Action spectra for the cytotoxic action of electromagnetic radiation in the solar range 280-434 nm have been determined for human fibroblasts and epidermal keratinocytes derived from the same foreskin biopsy. The spectra for the two cell types are close to identical and coincide with our previously published data for a human lymphoblastoid line indicating that the mechanism of inactivation of

Rex M. Tyrrell; Mireille Pidoux

365

Gauge invariant fractional electromagnetic fields  

NASA Astrophysics Data System (ADS)

Fractional derivatives and integrations of non-integers orders was introduced more than three centuries ago but only recently gained more attention due to its application on nonlocal phenomenas. In this context, several formulations of fractional electromagnetic fields was proposed, but all these theories suffer from the absence of an effective fractional vector calculus, and in general are non-causal or spatially asymmetric. In order to deal with these difficulties, we propose a spatially symmetric and causal gauge invariant fractional electromagnetic field from a Lagrangian formulation. From our fractional Maxwell's fields arose a definition for the fractional gradient, divergent and curl operators.

Lazo, Matheus Jatkoske

2011-09-01

366

Introduction to The Electromagnetic Spectrum  

NSDL National Science Digital Library

This NASA-created web site introduces electromagnetic waves and their behaviors to secondary learners. Each region of the spectrum is described, illustrated, and accompanied by video clips. Within each section, the authors explore the relationship between wavelength and wave type and provide information about how scientists detect the various waves and collect images of their emissions. Don't miss the link to NASA's Tour of the Electromagnetic Spectrum, a free set of 24 posters, which can be viewed online or printed for the classroom. This tutorial is part of NASA's Mission: Science website.

2009-10-05

367

REVIEWS OF TOPICAL PROBLEMS: Thermally stimulated electromagnetic fields of solids  

NASA Astrophysics Data System (ADS)

Different ways to calculate the spectral properties of fluctuating electromagnetic fields produced by solids are reviewed, all of which essentially reduce to solving the Maxwell equations for a specified geometry and boundary conditions and then using the fluctuation--dissipation theorem. It is shown that in the practical case of plane-layered solids, all correlation characteristics of thermal fields can be expressed in terms of the Fresnel coefficients. The experimental results on thermally stimulated electromagnetic fields from solids are in qualitative and quantitative agreement with model calculations and theoretical expectations. The dispersion interaction between solid bodies in different thermodynamic states, the fluctuating fields as a means of body-to-body energy transfer, and the shift, broadening, and deexcitation of energy levels in a particle near a solid surface are discussed using the theory of thermally stimulated electromagnetic fields.

Vinogradov, Evgeny A.; Dorofeev, Illarion A.

2009-05-01

368

[Occupational exposure to electromagnetic fields in physiotherapy departments].  

PubMed

An assessment of the electromagnetic fields emitted from short and ultrashort wave diathermy sources and from magneto therapy operating at a frequency of 50 Hz was made to evaluate the occupational exposure to the operators. Operators were exposed to electromagnetic fields which rarely exceed the recommended limits of International Commission on Non-Ionizing Radiation Protection (ICNIRP) and American Conference of Governmental Industrial Hygienists (ACGIH). Only a measurement of electromagnetic fields near short wave diathermy equipment operating at a frequency of 27.12 MHz exposed operators to levels above those recommended by ICNIRP at a distance of 1 metre. Magnetic fields of magneto therapy exceeded residential exposition of 1 microtesla, at a distance of 4 metres. PMID:12528353

Maccà, I; Scapellato, M L; Perini, M; Virgili, A; Saia, B; Bartolucci, G B

369

Methodology for Selecting an Electromagnetic Gun System.  

National Technical Information Service (NTIS)

This thesis proposes a methodology for selecting an electromagnetic launcher (EML) based upon mission requirements and available technology. The intent of the study is twofold. First, it reviews electromagnetic launcher applications, the principles of ele...

K. E. Reinhard

1992-01-01

370

Numerical Analysis of Electromagnetic Bandgap Structures.  

National Technical Information Service (NTIS)

Electromagnetic bandgap (EBG) structures and negative index of refraction (NIR) meta-materials are periodic dielectric or metallic material structures that allow greater control over electromagnetic waves than has previously been possible. Man-made versio...

R. S. Schechter S. T. Chun

2007-01-01

371

Electromagnetic Radiation System (EMRS) for Susceptibility Testing.  

National Technical Information Service (NTIS)

The function of the Electromagnetic Radiation System (EMRS) is to generate electromagnetic energy so as to produce a constant field strength that can be automatically scanned as a function of frequency. The design objective is to cover the frequency range...

J. M. VanArsdale

1978-01-01

372

Electromagnetic Radiation System (EMRS) for Susceptibility Testing.  

National Technical Information Service (NTIS)

The function of the Electromagnetic Radiation System (EMRS) is to generate electromagnetic energy so as to produce a constant field strength that can be automatically scanned as a function of frequency. The design objective is to cover the frequency range...

E. S. Iskra

1976-01-01

373

Electromagnetic Radiation System (EMRS) for Susceptibility Testing.  

National Technical Information Service (NTIS)

The function of the Electromagnetic Radiation System (EMRS) is to generate electromagnetic energy so as to produce a constant field strength that can be automatically scanned as a function of frequency. The design objective is to cover the frequency range...

E. S. Iskra

1977-01-01

374

Electromagnetic Radiation System (EMRS) for Susceptibility Testing.  

National Technical Information Service (NTIS)

The Electromagnetic Radiation System (EMRS) is designed to generate electromagnetic energy to produce a constant field strength while scanned automatically in frequency. Design objective was 200 volts per meter from 30 Hz to 40 GHz. This report describes ...

J. V. Arsdale

1981-01-01

375

Electromagnetic Radiation System (EMRS) for Susceptibility Testing.  

National Technical Information Service (NTIS)

The function of the Electromagnetic Radiation System (EMRS) is to generate electromagnetic energy to produce a constant field strength that can be automatically scanned as a function of frequency. The design objective is to cover the frequency range of 30...

M. V. Stone

1979-01-01

376

Electromagnetic Compatibility of Nuclear Power Plants.  

National Technical Information Service (NTIS)

Lately, there has been a mounting concern about the electromagnetic compatibility of nuclear-power-plant systems mainly because of the effects due to the nuclear electromagnetic pulse, and also because of the introduction of more-sophisticated and, theref...

H. S. Cabayan

1983-01-01

377

Galium Electromagnetic (GEM) Thruster Concept and Design.  

National Technical Information Service (NTIS)

We describe the design of a new type of two-stage pulsed electromagnetic accelerator, the gallium electromagnetic (GEM) thruster. A schematic illustration of the GEM thruster concept is given. In this concept, liquid gallium propellant is pumped into the ...

K. A. Polzin T. E. Markusic

2005-01-01

378

Visible Light and the Electromagnetic Spectrum  

NSDL National Science Digital Library

During this lesson, the electromagnetic spectrum is explained and students learn that visible light makes up only a portion of this wide spectrum. Students also learn that engineers use electromagnetic waves for many different applications.

Integrated Teaching And Learning Program

379

Electromagnetic coupling on complex systems - Topological approach  

Microsoft Academic Search

The principles of electromagnetic topology, developed by Baum, are reviewed. The method involves breaking a complex electromagnetic problem down into several small ones that are easier to solve. An example is used to illustrate the advantages of the approach.

J. P. Parmantier; G. Labaume; J. C. Alliot; P. Degauque

1990-01-01

380

3D Electromagnetic Field Analysis for Mixing Suspension Electromagnet Used by Maglev Train  

Microsoft Academic Search

A maglev train is supported by electromagnetic force between suspension electromagnet and track and is driven by linear motor. The suspension electromagnet is an important part of a maglev train. Its operating characteristic has a direct bearing on technology-economy performance and run safety of the whole train. The paper advances a new electromagnet structure mixing permanent magnet with electric excitation

Liu Shaoke; Guo Zhongjun; Chen Guirong

2010-01-01

381

Electromagnetic design considerations for fast acting controllers  

SciTech Connect

Electromagnetic design considerations for fast acting controllers in a power system is introduced and defined. A distinction is made in relation to the more commonly understood system control design necessary for damping electromechanical oscillations using stability programs and eigenanalysis. Electromagnetic eigenanalysis tools have limited availability and are consequently rarely used. Electromagnetic transients programs (emtp) on the other hand are widely used and a procedure for undertaking electromagnetic control design of fast acting controllers in a power system using emtp is presented.

Woodford, D.A. [Manitoba HVDC Research Centre, Winnipeg, Manitoba (Canada)

1996-07-01

382

The electromagnetic spectrum : waves of energy  

NSDL National Science Digital Library

In this lesson, students will (1) understand that the sun energy is transferred to Earth by electromagnetic waves, which are transverse waves, (2) understand that there are eight main types of electromagnetic waves, classified on the electromagnetic spectrum according to their wavelengths, and (3) understand how each of the types of electromagnetic radiation is used or found in our everyday lives. This would be a suitable activity for small groups.

Coulson, Tracy; Kennedy, Karen

2002-01-01

383

Scattering of an ultrashort electromagnetic radiation pulse by an atom in a broad spectral range  

SciTech Connect

The scattering of an ultrashort electromagnetic pulse by atomic particles is described using a consistent quantum-mechanical approach taking into account excitation of a target and nondipole electromagnetic interaction, which is valid in a broad spectral range. This approach is applied to the scattering of single- and few-cycle pulses by a multielectron atom and a hydrogen atom. Scattering spectra are obtained for ultrashort pulses of different durations. The relative contribution of 'elastic' scattering of a single-cycle pulse by a hydrogen atom is studied in the high-frequency limit as a function of the carrier frequency and scattering angle.

Astapenko, V. A., E-mail: astval@mail.ru [Moscow Institute of Physics and Technology (Russian Federation)

2011-02-15

384

The theory of the electromagnetic field  

Microsoft Academic Search

Aspects related to the concepts of charge and current are considered along with the effect of the electromagnetic field on general charge distributions, the electrical field produced by static charges, the magnetic induction field produced by steady currents, the electromagnetic field produced by time-dependent charge distributions, plane electromagnetic waves in vacuum, problems of potential theory, and time-dependent fields in the

D. M. Cook

1975-01-01

385

Smart electromagnetic structures: The neural antenna  

Microsoft Academic Search

Smart electromagnetic structures (SEMS) are defined as structures capable of interacting with their surrounding electromagnetic fields and either influencing the field or sensing and adapting to its presence. A structure is smart when it integrates sensing elements (e.g., antennas), processing elements (neural networks) and control elements (diodes) autonomously. SEMS provide an adaptive electromagnetic (EM) environment for the structure on which

Michael H. Thursby

1993-01-01

386

Electromagnetism radialization protection in interior design  

Microsoft Academic Search

With the increasing electromagnetic radiation of household appliances, the impacts of electromagnetic radiation on the people are larger than before. This paper aims to solve the problems which reducing the electromagnetic radiation at maximum extent by displaying furnitures or plants and using materials in the interior house design. There is big distinction when people displace the household appliances on different

Zhihao Zou; Weiping Hu; Yanyan Wang

2008-01-01

387

Resource Letter EM-1: Electromagnetic Momentum  

NASA Astrophysics Data System (ADS)

This Resource Letter surveys the literature on momentum in electromagnetic fields, including the general theory, the relation between electromagnetic momentum and vector potential, ``hidden'' momentum, the 4/3 problem for electromagnetic mass, and the Abraham-Minkowski controversy regarding the field momentum in polarizable and magnetizable media.

Griffiths, David J.

2012-01-01

388

Transient electromagnetic effects on networks using CRIPTE  

Microsoft Academic Search

A novel simulation approach to electromagnetic computations involving large, complex systems is described for studying the effects of high power radio-frequency pulses. The approach uses the electromagnetic topology method. The adoption of the multi-conductor transmission analysis gives the results that are in good agreement with other solution methods. The electromagnetic topology method has been extended to the analysis of buried

Naz E. Islam; S. Joe Yakura; J. P. Parmantier

2002-01-01

389

An overview of the electromagnetic topology  

Microsoft Academic Search

A general description of the electromagnetic topology method is presented with emphasis on the topological diagram and interaction graph. Quantitative treatment of electromagnetic interactions is considered, and for a general case, a model physically representing the propagation channels of electromagnetic signals and their scattering in topological volumes is derived. A multiconductor transmission line network is analyzed, and simplifications and approximations

J. P. Parmantier; X. Ferrieres; J. P. Aparicio; J. C. Alliot

1991-01-01

390

Electromagnetic aircraft launch system-EMALS  

Microsoft Academic Search

With the proliferation of electromagnetic launch systems presently being designed, built, or studied, there appears to be no limit to their application. One of the intriguing applications is electromagnetically catapulting aircraft from the deck of an aircraft carrier. The US Navy had foreseen the substantial capabilities of an electromagnetic catapult in the 1940s and built a prototype. However, it was

Michael R. Doyle; Douglas J. Samuel; Thomas Conway; Robert R. Klimowski

1995-01-01

391

Beta decay and other processes in strong electromagnetic fields  

SciTech Connect

We consider effects of the fields of strong electromagnetic waves on various characteristics of quantum processes. After a qualitative discussion of the effects of external fields on the energy spectra and angular distributions of the final-state particles as well as on the total probabilities of the processes (such as decay rates and total cross sections), we present a simple method of calculating the total probabilities of processes with production of nonrelativistic charged particles. Using nuclear {beta} decay as an example, we study the weak- and strong-field limits, as well as the field-induced {beta} decay of nuclei stable in the absence of the external fields, both in the tunneling and multiphoton regimes. We also consider the possibility of accelerating forbidden nuclear {beta} decays by lifting the forbiddeness due to the interaction of the parent or daughter nuclei with the field of a strong electromagnetic wave. It is shown that for currently attainable electromagnetic fields all effects on total {beta}-decay rates are unobservably small.

Akhmedov, E. Kh., E-mail: akhmedov@mpi-hd.mpg.de [Max-Planck-Institut fuer Kernphysik (Germany)

2011-09-15

392

Integrating electromagnetic launchers on ships  

Microsoft Academic Search

Naval combatant ships of the future will have high power electrically powered weapons systems, including electromagnetic launchers. Integrating high power electric gun systems into ships poses unique issues that ship designers have not faced before. These issues must be identified and addressed early in the conceptual design stage for successful development and integration of high power electric gun systems into

Antonios Challita; John Barber; John Ykema; Cliff Allen

2004-01-01

393

The courts and electromagnetic fields  

SciTech Connect

This article examines the recent development in eminent domain cases involving power transmission line rights of way, the issue of fear of the mythical buyer. The author feels that the fear of electrocution or of the possible cancer-inducing effects of electromagnetic fields is greatly influencing court decisions in these cases. The results could be more expensive rights of way acquisition by utilities.

Freeman, M. (Univ. of Pennsylvania, Philadelphia (United States))

1990-07-19

394

Chopper-Operated Electromagnetic Flowmeter  

Microsoft Academic Search

The problem of design of a square-wave electromagnetic flowmeter may be simplified by the use of a mechanical chopper as the gating device. Such an instrument has been assembled using commercial components costing less than $1000. A commercial 400-cycle chopper amplifier, Offner model 190, was modified to perform the sampling. Carrier signal was provided by Tektronix 162 and 161 generators.

Francis L. Abel

1959-01-01

395

Ferro tale: electromagnetic animation interface  

Microsoft Academic Search

In this video we demonstrate the idea and the prototype of an electromagnetic animation interface, ferro tale. Ferromagnetic particles, such as iron filings, have very fascinating characteristics. Therefore they are widely used in art, education and as toys. Besides their potential to enable visual and tactile feedback and to be used as a medium for high resolution tangible input, peoples

Nan Zhao; Xiang Cao; Jaturont Jamigranont

2012-01-01

396

Electromagnetic Levitation of a Disc  

ERIC Educational Resources Information Center

This paper presents a teaching experiment that explores the levitation of a disc of ferromagnetic material in the presence of the magnetic field produced by a single electromagnet. In comparison to the classical experiment of the levitation of a sphere, the main advantage of the proposed laboratory bench is that the uniform magnetic field…

Valle, R.; Neves, F.; de Andrade, R., Jr.; Stephan, R. M.

2012-01-01

397

Electromagnetic interference from wind turbines  

Microsoft Academic Search

Summary form only given. During the late nineteen seventies and eighties the University of Michigan Radiation Laboratory, under sponsorship from the US Department of Energy, studied theoretically and experimentally the effects of wind turbines (WTs) on the performance of various electromagnetic systems. The article summarizes selected portions of the fundamental work carried out and techniques developed under the program which

D. L. Sengupta

1999-01-01

398

Finite formulation of electromagnetic field  

Microsoft Academic Search

We show that the equations of electromagnetism can be directly obtained in a finite form, i.e., discrete, thus avoiding the traditional discretization methods of Maxwell's differential equations. The finite formulation can be used with unstructured meshes in two and three dimensions and easily permits to obtain fourth-order convergence

Enzo Tonti; Piazzale Europa

2002-01-01

399

Finite Element Methods for Electromagnetics.  

National Technical Information Service (NTIS)

In the present report, an overview is given over a number of options for formulating finite-element methods for the computation of electromagnetic fields directly in terms of the electric and/or magnetic field components that are required. A number of exi...

I. E. Lager G. Mur

2000-01-01

400

Technology-based electromagnetic education  

Microsoft Academic Search

In this paper, we briefly review the various roles of technology in stimulating interest and deepening understanding of abstract and highly mathematical subjects such as electromagnetics (EM). The general advantages of using technology in offering Web-based courses and professional training are described and examples of the ongoing activities in this area are summarized. Focus, however, is placed on the development

Magdy F. Iskander

2002-01-01

401

Cell Effects of Electromagnetic Radiation  

Microsoft Academic Search

The effects of electromagnetic radiation on cells and cell organelles are reviewed. The original results of studies of the influence of monochrome and impulse radiation on human cells are presented. The heterochromatin granule quantity was investigated as a parameter indicating the state of human cell. It was shown that heterochromatin granule quantity and cell membrane permeability increases under the influence

Y. G. Shckorbatov; N. N. Kolchigin; V. A. Grabina; V. N. Pasiuga; O. V. Kazansky

2006-01-01

402

Electromagnetic radiation and biological effects  

Microsoft Academic Search

A review on biological effects of low power radiation on humans and animals is presented. Effects of electromagnetic coupling between the cellular\\/PCS phone antenna and the human head model have been described. Theoretical plots of the near-field patterns are shown for the human brain. An Independent Expert Group on Mobile Phones (IEGMP) of the UK discourages the use of mobile

A. Kumar

2001-01-01

403

A new electromagnetic valve actuator  

Microsoft Academic Search

In conventional internal combustion (IC) engines, en- gine valve displacements are fixed relative to crankshaft position. If these valves are actuated as a variable function of crankshaft an- gle, significant improvements in fuel economy can be achieved. Ex- isting electromagnetically actuated variable-valve-timing (VVT) systems characteristically use springs to provide the large iner- tial power to move the engine valves. However,

W. S. Changt; T. A. Parlikart; M. D. Seemant; D. J. Perreaultt; J. G. Kassakian; T. A. Keirnl

2002-01-01

404

Electromagnetic Levitation of a Disc  

ERIC Educational Resources Information Center

|This paper presents a teaching experiment that explores the levitation of a disc of ferromagnetic material in the presence of the magnetic field produced by a single electromagnet. In comparison to the classical experiment of the levitation of a sphere, the main advantage of the proposed laboratory bench is that the uniform magnetic field…

Valle, R.; Neves, F.; de Andrade, R., Jr.; Stephan, R. M.

2012-01-01

405

Electromagnetic focusing in biological tissues  

Microsoft Academic Search

In this work we assess the feasibility of focused electromagnetic ablation of breast cancer. In our approach we consider two degrees of freedom, namely the bolus permittivity and the operational frequency. The electric fi elds in at wo- dimensional configuration are computed per source using the iterative conjugate gradient method. The fields are subsequently focused in two lesions. The focusing

W. M. Brink; I. E. Lager; B. J. Kooij

2011-01-01

406

Electromagnetic Interactions and Hadronic Structure  

NASA Astrophysics Data System (ADS)

1. Quark models of hadrons and issues in quark dynamics; 2. Elastic form factors; 3. Electromagnetic excitations of nucleon resonances; 4. Meson radiative decays; 5. Intermediate-energy photoproduction; 6. Chiral perturbation theory; 7. Spin structure functions; 8. Diffraction and colour dipoles; 9. Generalized parton distributions; 10. Quark-hadron duality; 11. Colour transparency; Index.

Close, Frank; Donnachie, Sandy; Shaw, Graham

2007-05-01

407

Electromagnetic Interactions and Hadronic Structure  

NASA Astrophysics Data System (ADS)

1. Quark models of hadrons and issues in quark dynamics; 2. Elastic form factors; 3. Electromagnetic excitations of nucleon resonances; 4. Meson radiative decays; 5. Intermediate-energy photoproduction; 6. Chiral perturbation theory; 7. Spin structure functions; 8. Diffraction and colour dipoles; 9. Generalized parton distributions; 10. Quark-hadron duality; 11. Colour transparency; Index.

Close, Frank; Donnachie, Sandy; Shaw, Graham

2009-07-01

408

Electromagnetic backscatter predictions using XPATCH  

Microsoft Academic Search

The ability to accurately identify objects solely from their electromagnetic backscatter is of continuing interest. In order for object identification to be practical, a comprehensive catalog of signatures must be generated. The prediction code XPATCH is one tool capable of generating such a catalog. It is a high frequency polarimetric code based on the shooting and bouncing ray (SBR) method,

R. O. Jernejcic; R. F. Schindel

1994-01-01

409

Electromagnetic topology - Junction characterization methods  

Microsoft Academic Search

The electrical characterization of topological network junctions using a formalism in accordance with electromagnetic topology is discussed. It is shown how the characteristic impedance of the network in which the junction is located can be chosen to treat several physical cable connection and termination configurations. Junctions which represent the separation of a conductor into other conductors are used as an

J. P. Parmantier; G. Labaume; J. C. Alliot; P. Degauque

1990-01-01

410

Electromagnetic configurations of rail guns  

Microsoft Academic Search

Some problems associated with the electromagnetic acceleration of macrobodies in a rail gun are examined. An approach to the design of rail gun configurations is proposed, and some basic rail gun schemes are synthesized. The alternative rail gun schemes are compared in terms of electrode potential and stability of the electrode gap with respect to parasitic current shunting. The effect

O. V. Fat'yanov; V. E. Ostashev; A. N. Lopyrev; A. V. Ul'Yanov

1993-01-01

411

Electromagnetic fields near rail guns  

Microsoft Academic Search

The field in the neighborhood of an electromagnetic railgun is computed for the case of constant current. The analysis centers on the Westinghouse EMACK launcher in which two rails of 5-m length carry a peak current of 2.1 MA, while a peak power of over 10 GW is delivered to the rails. Expressions are derived for electric field strength and

William G. Soper

1989-01-01

412

Electromagnetically actuated ball valve micropumps  

Microsoft Academic Search

We present two types of oscillating diaphragm micropumps configured with passive ball valves and using electromagnetic actuation. One type is made out of poly(methyl methacrylate) (PMMA), while the other one is made out of borosilicate glass. Both were produced using the powder blasting microfabrication method. The pumping resonant frequency was measured to be within the range of 20-30 Hz for

Christophe Yamahata; Frédéric Lacharme; Jan Matter; Silvan Schnydrig; Yves Burri; Martin A. M. Gijs

2005-01-01

413

Computational design for electromagnetic simulations  

NASA Astrophysics Data System (ADS)

An automatic computational procedure has been developed to efficiently and accurately design the shape of complicated electromagnetic objects. These electromagnetic objects can be simulated for operation at high frequencies (˜10 GHz), and can be comprised of dissimilar materials. The automated design procedure consists of linking together an original electromagnetic field simulation tool, an original adjoint routine for obtaining sensitivity derivatives, and an original grid-smoothing tool with an existing optimization package. The electromagnetic field simulation software employs a temporally and spatially higher-order accurate Streamline Upwind/Petrov-Galerkin finite-element method that numerically solves Maxwell's equations in the time domain using implicit time stepping. The software for computing sensitivity derivatives employs a reverse-mode time-accurate discrete adjoint methodology that is formulated to automatically maintain consistency with the electromagnetic field simulation software. Grid smoothing is achieved using a spatially higher-order accurate Galerkin finite-element method that generates a numerical solution to the linear elastic equations. All computational solutions to the linear systems present in each software tool are obtained using the Generalized Minimum Residual algorithm with block diagonal preconditioning. Each software tool is implemented using a parallel processing paradigm and is therefore capable of being executed on a distributed memory supercomputer. The order of accuracy of the electromagnetic field simulation software has been determined by using comparisons with exact solutions. The field software's results were compared to the exact solution of a rectangular resonant cavity. In all cases, the order properties of the field software exceed theoretical expectations when linear, quadratic, and cubic tetrahedral elements are employed to discretize the field. To demonstrate the consistency of the adjoint-based sensitivity derivates with those obtained directly from the field solver, derivatives have been extracted from the field software using a complex variable technique. The sensitivity derivatives from the reverse-mode time-accurate discrete adjoint method were then compared and demonstrated to agree to at least seven decimal places. As a demonstration of the assembled technologies, the optimization procedure successfully and efficiently modified the shape of two electromagnetic objects to reduce a specified cost function. A dielectric cube, under the influence of a propagating plane wave, was repositioned within a larger free space volume so that the field variables on the surface of the cube match desired values at a specified time. A similar demonstration case has also been conducted to modify the shape of a dielectric ellipsoid, under the same conditions as the cube.

Glasby, Ryan Steven

414

Group independent component analysis of MR spectra.  

PubMed

This study investigates the potential of independent component analysis (ICA) to provide a data-driven approach for group level analysis of magnetic resonance (MR) spectra. ICA collectively analyzes data to identify maximally independent components, each of which captures covarying resonances, including those from different metabolic sources. A comparative evaluation of the ICA approach with the more established LCModel method in analyzing two different noise-free, artifact-free, simulated data sets of known compositions is presented. The results from such ideal simulations demonstrate the ability of data-driven ICA to decompose data and accurately extract components resembling modeled basis spectra from both data sets, whereas the LCModel results suffer when the underlying model deviates from assumptions, thus highlighting the sensitivity of model-based approaches to modeling inaccuracies. Analyses with simulated data show that independent component weights are good estimates of concentrations, even of metabolites with low intensity singlet peaks, such as scyllo-inositol. ICA is also applied to single voxel spectra from 193 subjects, without correcting for baseline variations, line-width broadening or noise. The results provide evidence that, despite the presence of confounding artifacts, ICA can be used to analyze in vivo spectra and extract resonances of interest. ICA is a promising technique for decomposing MR spectral data into components resembling metabolite resonances, and therefore has the potential to provide a data-driven alternative to the use of metabolite concentrations derived from curve-fitting individual spectra in making group comparisons. PMID:23785655

Kalyanam, Ravi; Boutte, David; Gasparovic, Chuck; Hutchison, Kent E; Calhoun, Vince D

2013-03-13

415

Artificial intelligence analysis of paraspinal power spectra.  

PubMed

OBJECTIVE: As an aid to discrimination of sufferers with back pain an artificial intelligence neural network was constructed to differentiate paraspinal power spectra. DESIGN: Clinical investigation using surface electromyography. METHOD: The surface electromyogram power spectra from 60 subjects, 33 non-back-pain sufferers and 27 chronic back pain sufferers were used to construct a back propagation neural network that was then tested. Subjects were placed on a test frame in 30 degrees of lumbar forward flexion. An isometric load of two-thirds maximum voluntary contraction was held constant for 30 s whilst surface electromyograms were recorded at the level of the L(4-5). Paraspinal power spectra were calculated and loaded into the input layer of a three-layer back propagation network. The neural network classified the spectra into normal or back pain type. RESULTS: The back propagation neural was shown to have satisfactory convergence with a specificity of 79% and a sensitivity of 80%. CONCLUSIONS: Artificial intelligence neural networks appear to be a useful method of differentiating paraspinal power spectra in back-pain sufferers. PMID:11415655

Oliver, C W; Atsma, W J

1996-10-01

416

Gold nanoparticle dimer plasmonics: finite element method calculations of the electromagnetic enhancement to surface-enhanced Raman spectroscopy  

Microsoft Academic Search

Finite element method calculations were carried out to determine extinction spectra and the electromagnetic (EM) contributions\\u000a to surface-enhanced Raman spectroscopy (SERS) for 90-nm Au nanoparticle dimers modeled after experimental nanotags. The calculations\\u000a revealed that the EM properties depend significantly on the junction region, specifically the distance between the nanoparticles\\u000a for spacings of less than 1 nm. For extinction spectra, spacings below

Jeffrey M. McMahon; Anne-Isabelle Henry; Kristin L. Wustholz; Michael J. Natan; R. Griffith Freeman; Richard P. Van Duyne; George C. Schatz

2009-01-01

417

Computation of Spiral Spectra  

NASA Astrophysics Data System (ADS)

A computational linear stability analysis of spiral waves in a reaction-diffusion equation is performed on large disks. As the disk radius R increases, eigenvalue spectra converge to the absolute spectrum predicted by Sandstede and Scheel. The convergence rate is consistent with 1/R, except possibly near the edge of the spectrum. Eigenfunctions computed on large disks are compared with predicted exponential forms. Away from the edge of the absolute spectrum the agreement is excellent, while near the edge computed eigenfunctions deviate from predictions, probably due to finite-size effects. In addition to eigenvalues associated with the absolute spectrum, computations reveal point eigenvalues. The point eigenvalues and associated eigenfunctions responsible for both core and far-field breakup of spiral waves are shown.

Wheeler, Paul; Barkley, Dwight

2006-01-01

418

Electromagnetic methods in NDE  

Microsoft Academic Search

EM methods for NDE have reached a quantitative level of sophistication, and possess sound bases for both analytical and numerical modeling. Improvements in instrumentation, in conjunction with growing use of AI methods, can yield characterizations and sizing for a wide variety of flaw types. Attention is given to the advent of small linear arrays of small printed-circuit eddy current probes,

B. A. Auld

1993-01-01

419

Injuries from Electromagnetic Energy  

Microsoft Academic Search

Injury occurs when body tissues are subjected to levels of energy outside the normal tolerance bands. Excessive energy damages tissues, potentially beyond repair, and disrupts normal physiologic functioning. Injury may also occur when inadequate energy is available, such as extreme cold leading to frostbite injury, or disruption of normal cellular energy systems such as asphyxiation. Energy may be in the

STEPHEN A. MCCURDY

420

Performance of the AMS02 Electromagnetic Calorimeter in space  

NASA Astrophysics Data System (ADS)

The Alpha Magnetic Spectrometer (AMS-02) is a general purpose high energy particle detector which was successfully deployed on the International Space Station (ISS) on May 19, 2011 to conduct a long duration mission of fundamental physics research in space. After one year of operation, AMS-02 has collected more than 17 billions of events. The main scientific goals of the experiment are the searches for antimatter and dark matter, the high precision measurement of charged cosmic ray spectra and fluxes and the study of gamma rays, in the GeV to TeV energy range. In AMS-02, the Electromagnetic Calorimeter (ECAL) is required to measure e+, e- and gamma spectra and to discriminate electromagnetic showers from hadronic cascades. To fulfill these requirements the ECAL is based on a lead/scintillating fiber sandwich, providing a 3D imaging reconstruction of the showers. AMS-02 has been tested during Summer 2010 in a test beam at CERN, using 10 to 250 GeV electron and positron beams and proton beam at 400 GeV. After a summary of the AMS02 performance in space, results on the measurements of ECAL parameters and performance will be reviewed.

Rosier-Lees, Sylvie; AMS02 Collaboration

2012-12-01

421

Reflectance Spectra and Optical Constants of Pyrene Crystals  

Microsoft Academic Search

Reflectance spectra of pyrene have been measured on the ab plane of single crystals at 300 and 77 K. Refractive indices, complex dielectric constants and absorption coefficients are calculated for the a- and b-polarized components by Kramers-Kronig analysis of the reflectance spectra. Brief discussions on the Davydov splitting, vibrational levels, polarization ratios and the spectral change due to the phase

Kenichi Tomioka; Motoaki Iemura; Atsuo Matsui

1981-01-01

422

Electromagnetic interference (EMI) of system-on-package (SOP)  

Microsoft Academic Search

Electromagnetic interference (EMI) issues are expected to be crucial for next-generation system-on-package (SOP) integrated high-performance digital LSIs and for radio frequency (RF) and analog circuits. Ordinarily in SOPs, high-performance digital LSIs are sources of EMI, while RF and analog circuits are affected by EMI (victims). This paper describes the following aspects of EMI in SOPs: 1) die\\/package-level EMI; 2) substrate-level

Toshio Sudo; Hideki Sasaki; Norio Masuda; James L. Drewniak

2004-01-01

423

Transient evolutional behaviours of double-control electromagnetically induced transparency  

Microsoft Academic Search

The evolutional optical behaviours (turn-on dynamics) of a four-level double-control tripod-configuration (electromagnetically induced transparency) system are considered based on the transient solution to the equation of motion of the probability amplitudes of the atomic levels. As the most remarkable property (quantum interference between the two control transitions) will arise in the present tripod-configuration system, the transient evolution of the permittivity

Jian Qi Shen

2007-01-01

424

Electromagnetically induced gain in molecular systems  

NASA Astrophysics Data System (ADS)

We report electromagnetically induced gain in a highly degenerate two-level rotational vibrational molecular system. Using two photon (Raman-type) interaction with right and left circularly polarized pump and probe waves, the Zeeman coherence is established within the manifold of degenerate sublevels belonging to a rotational vibrational eigenstate. We analytically and numerically calculate the third-order nonlinear optical susceptibility for a Doppler-broadened molecular transition for an arbitrary high rotational angular momentum (J?20) . It is shown that for a Q -type open transition, a weak probe will experience an electromagnetically induced gain in presence of a strong copropagating pump wave. The inversionless gain originates due to cancellation of absorption from the interference of the coupled ? - and V-type excitation channels in an N -type configuration. A detailed analysis of the optical susceptibility as a function of Doppler detuning explains how the gain bands are generated in a narrow transparency window from the overlapping contributions of different velocity groups. It is shown that the orientation dependent coherent interaction in presence of a strong pump induces narrow resonances for the probe susceptibility. The locations, intensity, and sign (positive or negative susceptibility) of these resonances are decided by the frequency detuning of the Doppler group and the strength of the coupling field. The availability of high power tunable quantum cascade lasers covering a spectral region from about 4 to 12?m opens up the possibility of investigating the molecular vibrational rotational transitions for a variety of coherent effects.

Mukherjee, Nandini; Patel, C. Kumar N.

2009-12-01

425

Amplification of electromagnetic signals by ion channels.  

PubMed Central

Cells may respond to the exposure of low-frequency electromagnetic fields with changes in cell division, ion influx, chemical reaction rates, etc. The chain of events leading to such responses is difficult to study, mainly because of extremely small energies associated with low-frequency fields, usually much smaller than the thermal noise level. However, the presence of stochastic systems (for instance, ion channels) provides a basis for signal amplification, and could therefore, despite the low signal-to-noise ratio of the primary response, lead to the transmission of weak signals along the signaling pathways of cells. We have explored this possibility for an ion channel model, and we present a theory, based on the formalism of stochastically driven processes, that relates the time averages of the ion channel currents to the amplitude and frequency of the applied signal. It is concluded from this theory that the signal-to-noise ratio increases with the number of channels, the magnitude of the rate constants, and the frequency response of the intracellular sensing system (for instance, a calcium oscillator). The amplification properties of the stochastic system are further deduced from numerical simulations carried out on the model, which consists of multiple identical two-state channels, and the behavior for different parameters is examined. Numerical estimates of the parameters show that under optimum conditions, even very weak low-frequency electromagnetic signals (<100 Hz and down to 100 microT) may be detected in a cellular system with a large number of ion channels.

Galvanovskis, J; Sandblom, J

1997-01-01

426

Electromagnetically induced gain in molecular systems  

SciTech Connect

We report electromagnetically induced gain in a highly degenerate two-level rotational vibrational molecular system. Using two photon (Raman-type) interaction with right and left circularly polarized pump and probe waves, the Zeeman coherence is established within the manifold of degenerate sublevels belonging to a rotational vibrational eigenstate. We analytically and numerically calculate the third-order nonlinear optical susceptibility for a Doppler-broadened molecular transition for an arbitrary high rotational angular momentum (J>=20). It is shown that for a Q-type open transition, a weak probe will experience an electromagnetically induced gain in presence of a strong copropagating pump wave. The inversionless gain originates due to cancellation of absorption from the interference of the coupled LAMBDA- and V-type excitation channels in an N-type configuration. A detailed analysis of the optical susceptibility as a function of Doppler detuning explains how the gain bands are generated in a narrow transparency window from the overlapping contributions of different velocity groups. It is shown that the orientation dependent coherent interaction in presence of a strong pump induces narrow resonances for the probe susceptibility. The locations, intensity, and sign (positive or negative susceptibility) of these resonances are decided by the frequency detuning of the Doppler group and the strength of the coupling field. The availability of high power tunable quantum cascade lasers covering a spectral region from about 4 to 12 mum opens up the possibility of investigating the molecular vibrational rotational transitions for a variety of coherent effects.

Mukherjee, Nandini; Patel, C. Kumar N. [Department of Physics and Astronomy, University of California, Los Angeles, California 90095 (United States)

2009-12-15

427

Computation of Synthetic Spectra from Simulations of Relativistic Shocks  

NASA Astrophysics Data System (ADS)

Particle-in-cell (PIC) simulations of relativistic shocks are in principle capable of predicting the spectra of photons that are radiated incoherently by the accelerated particles. The most direct method evaluates the spectrum using the fields given by the Liénard-Wiechart potentials. However, for relativistic particles this procedure is computationally expensive. Here we present an alternative method that uses the concept of the photon formation length. The algorithm is suitable for evaluating spectra both from particles moving in a specific realization of a turbulent electromagnetic field or from trajectories given as a finite, discrete time series by a PIC simulation. The main advantage of the method is that it identifies the intrinsic spectral features and filters out those that are artifacts of the limited time resolution and finite duration of input trajectories.

Reville, Brian; Kirk, John G.

2010-12-01

428

Electromagnetically induced transparency with quantum interferometry  

NASA Astrophysics Data System (ADS)

We have shown that electromagnetically induced transparency can be achieved by control-probe interferometry using two delayed phase-locked ultrashort pulses. Two vibrational wavepackets on the excited state, excited by two delayed phase-locked ultrashort pulses, interfere constructively or destructively leading to enhancement or suppression of absorption to a selective set of vibrational levels. Depending on the phase difference and the delay between the pulses with same carrier frequency, one can design different transparency windows between absorption peaks at consecutive even(odd) vibrational levels by eliminating absorption at odd(even) vibrational levels. We have shown that by switching the phase difference of two delayed femtosecond pulses, one can switch to complete elimination of absorption from enhanced absorption to a particular set of vibrational levels in the excited state. Thus, switching of transparency through window between odd vibrational levels to that between even vibrational levels is possible. By properly choosing the temporal width and the carrier frequency of the pulses, lossless transmission of complete or bands of frequencies of the pulses can be achieved through these transparency windows. Hence, designing of single- or multi-mode transparency windows in NaH molecule is feasible by control-probe quantum interferometry.

Bhattacharjee, Anindita; Dastidar, Krishna Rai

2012-02-01

429

Autoimmune processes after long-term low-level exposure to electromagnetic fields (experimental results) part 3. The effect of long-term nonthermal RF EMF exposure on complement-fixation antibodies against homologenous tissue  

Microsoft Academic Search

The effect of long-term nonthermal EMF exposure of 2450 MHz (500 ?W\\/cm2) on the level of antibodies against brain and liver tissues is studied on rats by the complement-fixation test (CFT) in the\\u000a cold. It is found that a statistically significant increase in the level of antibodies against aqueous extracts of brain and\\u000a liver tissues in blood serum is detected

A. A. Ivanov; Y. G. Grigoriev; V. N. Maltsev; A. M. Ulanova; N. M. Stavrakova; V. G. Skachkova; O. A. Grigoriev

2010-01-01

430

Cosmology from quasar spectra  

NASA Astrophysics Data System (ADS)

High resolution spectroscopy of high redshift quasar spectra enables us to investigate the properties of the intergalactic medium (IGM) and measure cosmological parameters from the Lya forest. Toward high precision cosmology, this dissertation presents the following four topics. (1) Principal Component Analysis (PCA) on quasar spectrum: We introduce the PCA to describe quasar emission lines and continua quantitatively, and we attempt to make a prediction of the continuum shape in the Lya forest using wavelengths redward of Lya emission. (2) Flux calibration of Keck HIRES data: On our way to achieve high accuracy measurement, it was necessary to develop new calibration schemes and explore the origin of systematic errors. My contribution includes the following and is discussed throughout the thesis: (i) the development of the flux calibration scheme, (ii) the discovery of three emission lines in the Lya forest, (iii) the establishment of high resolution standard star spectra, and (iv) the identification of ozone lines in the spectrum. (3) D/H measurement: We present precise measurements of the primordial deuterium to hydrogen ratio (D/ H) toward two quasars, HS0105+1619 and Q1243+3047, which constrains the baryon to photon ratio e = 5.9 +/- 0.5 x 10 -10 or the baryon density O b h 2 = 0.0214 +/- 0.0020 via the Big Bang Nucleosynthesis theory. (4) Studies of the Lya forest at z ~ 2: We also present the measurements of the total amount of neutral hydrogen absorption in the IGM. We compare our observed data with hydrodynamic simulations and find good agreement when we use the following cosmological parameters: H o = 71 kin s -1 Mpc -1 , O L = 0.73, O m = 0.27, O b = 0.044, the amplitude of the power spectrum s 8 = 0.9, and the photoinization rate G 912 = (1.44 +/- 0.11) x 10 -12 s -1 . We conclude that the measurements of the cosmological parameters from our primordial D/H measurements, recent WMAP satellite observation of the cosmic microwave background, and our the total amount of neutral hydrogen in the IGM at z ~ 2 are in a concordance with the LCDM model.

Suzuki, Nao

2005-11-01

431

Photoelectron spectra in an autoionization system interacting with a neighboring atom  

SciTech Connect

Photoelectron ionization spectra of an autoionization system with one discrete level interacting with a neighbor two-level atom are discussed. The formula for long-time ionization spectra is derived. According to this formula, the spectra can be composed of up to eight peaks. Moreover, the Fano-like zeros for weak optical pumping are identified in these spectra. The conditional ionization spectra depending on the state of the neighbor atom exhibit oscillations at the Rabi frequency. Dynamical spectral zeros occurring once per the Rabi period are revealed in these spectra.

Perina, Jan Jr. [Joint Laboratory of Optics, Institute of Physics of ASCR, 17 Listopadu 50a, CZ-772 07 Olomouc (Czech Republic); Luks, Antonin; Perinova, Vlasta [Joint Laboratory of Optics, Palacky University, RCPTM, 17 Listopadu 12, CZ-771 46 Olomouc (Czech Republic); Leonski, Wieslaw [Quantum Optics and Engineering Division, Institute of Physics, University of Zielona Gora, Prof. Z. Szafrana 4a, PL-65-516 Zielona Gora (Poland)

2011-05-15

432

Electromagnetic transduction of ultrasonic waves  

NASA Astrophysics Data System (ADS)

Excitation and detection of ultrasonic vibrations without physical contact has proven to be of great commercial value. First used to excite the resonant vibration of bar shaped laboratory specimens in the 1930's, it was Bruce Thompson's contributions in 1973-5 that launched their practical application to a wide range of difficult NDE problems. As a fresh PhD, he championed the use of mathematical models for the electromagnetic transduction process in order to guide the design and construction of practical transducers. His early papers presented both theoretical and experimental results that exposed the wide range of wave types that could be generated along with the environmental conditions that could be overcome. Several laboratories around the world established research programs to apply the electromagnetic transducer (EMAT) to specific NDE problems. This paper will summarize those applications made by the authors.

Passarelli, Frank; Alers, George; Alers, Ron

2012-05-01

433

Electromagnetic moments of quasistable particle  

SciTech Connect

We deal with the problem of assigning electromagnetic moments to a quasistable particle (i.e., a particle with mass located at the particle's decay threshold). In this case, an application of a small external electromagnetic field changes the energy in a nonanalytic way, which makes it difficult to assign definitive moments. On the example of a spin-1/2 field with mass M{sub *} interacting with two fields of masses M and m, we show how a conventionally defined magnetic dipole moment diverges at M{sub *}=M+m. We then show that the conventional definition makes sense only when the values of the applied magnetic field B satisfy |eB|/2M{sub *}<<|M{sub *}-M-m|. We discuss implications of these results to existing studies in electroweak theory, chiral effective-field theory, and lattice QCD.

Ledwig, Tim; Pascalutsa, Vladimir; Vanderhaeghen, Marc [Institut fuer Kernphysik, Johannes Gutenberg Universitaet Mainz, D-55099 Mainz (Germany)

2010-11-01

434

Time domain electromagnetic metal detectors  

SciTech Connect

This presentation focuses on illustrating by case histories the range of applications and limitations of time domain electromagnetic (TDEM) systems for buried metal detection. Advantages claimed for TDEM metal detectors are: independent of instrument response (Geonics EM61) to surrounding soil and rock type; simple anomaly shape; mitigation of interference by ambient electromagnetic noise; and responsive to both ferrous and non-ferrous metallic targets. The data in all case histories to be presented were acquired with the Geonics EM61 TDEM system. Case histories are a test bed site on Molokai, Hawaii; Fort Monroe, Virginia; and USDOE, Rocky Flats Plant. The present limitations of this technology are: discrimination capabilities in terms of type of ordnance, and depth of burial is limited, and ability of resolving targets with small metallic ambient needs to be improved.

Hoekstra, P.

1996-04-01

435

Electromagnetic Activation of Capillary Switches  

NASA Astrophysics Data System (ADS)

By designing coupled droplet pairs with the appropriate length scale to promote surface tension as the dominant force, one can create bi-stable capillary switches. This bi-stability can be triggered by pressure pulses, surface chemistry, electroosmosis, or body forces. To exploit the latter, we designed a capillary switch with electromagnetic activation. The resulting setup consists of a sub-millimeter tube, overfilled with a ferrofluid, surrounded by a wire coil to generate a magnetic field. Evidence of this capillary switching will be presented along with some theoretical basis in fluid- and electro-dynamics. The approach may also be used to investigate other transport phenomena in electromagnetically-coupled microfluidic systems, including the relative effects of translational motion of the ferrofluid (both particles and solvent molecules) versus the rotational effects of the individual magnetic grains. These individually addressable capillary switches offer intriguing applications including high-speed adaptive optics, actuators at the microscale, and possible PCB integration.

Malouin, Bernie; Dayal, Rohan; Parsa, Leila; Hirsa, Amir

2008-11-01

436

Electromagnetic tracking for catheter localization  

NASA Astrophysics Data System (ADS)

A low frequency AC electromagnetic tracking system is presented that is capable of determining the position and orientation of a catheter tip. Advantages of using magnetic tracking for this application is that magnetic fields are non-ionizing and pass through the human body with minimal attenuation. Low frequency fields are used to mitigate the effects of eddy currents induced in conductive materials found in the environment. There are two significant differences between this and other magnetic tracking technologies, these being (1) the use of a single magnetic sensing coil for position and orientation determination and (2) the eliminating of range restrictions between the sensing antenna and the magnetic field generators. This paper will discuss the general theory of electromagnetic tracking, why it is that researchers have an intense interest for internal tracking and a comparison of the new and old tracking technologies. Some applications of this tracking technology will also be presented.

Schneider, Mark R.

1999-07-01

437

Falling Magnets and Electromagnetic Braking  

NASA Astrophysics Data System (ADS)

The slow fall of a rare earth magnet through a copper pipe is a striking example of electromagnetic braking; this remarkable phenomenon has been the subject of a number of scientific paper s [1, 2]. In a pipe having radius R and wall thickness D, the terminal velocity of the falling magnet is proportional to (R?4)/D. It is interesting to ask what happens in the limit as D becomes very large. We report our experimental observations and theoretical predictions of the dependence of the terminal velocity on pipe radius R for large D. [1] Y. Levin, F.L. da Silveira, and F.B. Rizzato, ``Electromagnetic braking: A simple quantitative model''. American Journal of Physics, 74(9): p. 815-817 (2006). [2] J.A. Pelesko, M. Cesky, and S. Huertas, Lenz's law and dimensional analysis. American Journal of Physics, 3(1): p. 37-39. 2005.

Culbreath, Christopher; Palffy-Muhoray, Peter

2009-03-01

438

Electromagnetic response of Weyl semimetals.  

PubMed

It has been suggested recently, based on subtle field-theoretical considerations, that the electromagnetic response of Weyl semimetals and the closely related Weyl insulators can be characterized by an axion term ?E·B with space and time dependent axion angle ?(r,t). Here we construct a minimal lattice model of the Weyl medium and study its electromagnetic response by a combination of analytical and numerical techniques. We confirm the existence of the anomalous Hall effect expected on the basis of the field theory treatment. We find, contrary to the latter, that chiral magnetic effect (that is, ground state charge current induced by the applied magnetic field) is absent in both the semimetal and the insulator phase. We elucidate the reasons for this discrepancy. PMID:23889433

Vazifeh, M M; Franz, M

2013-07-09

439

Electromagnetic-gravitational energy systems  

Microsoft Academic Search

Two methods are considered to 'tap' the earth's rotational energy. This ancient 'collapsed gravitational energy' exceeds the earth-lunar binding energy. One involves an orbiting 'electromagnetic-gravitational' coupling system whereby the earth's rotation, with its nonuniform mass distribution, first uses gravity to add orbital energy to a satellite, similar to a planetary 'flyby'. The second stage involves enhanced satellite 'drag' as current-carrying

K. H. Schatten

1981-01-01

440

Electromagnetic-gravitational energy systems  

Microsoft Academic Search

Two methods axe considered to “tap” the earths' rotational energy. This ancient “collapsed gravitational energy” exceeds the earth-lunar binding energy. One involves an orbiting “electromagnetic-gravitational” coupling system whereby the earth's rotation, with its nonuniform mass distribution, first uses gravity to add orbital energy to a satellite, similar to a planetary “flyby.rd The second stage involves enhanced satellite “drag” as current-carrying

Kenneth H. Schatten

1981-01-01

441

Electromagnetic Spectrum of Am241  

Microsoft Academic Search

The electromagnetic spectrum of Am241 has been studied with a ten-inch bent-crystal spectrometer and a sodium iodide scintillation counter. Twelve gamma rays, sixteen Np L x-rays, and eight Am L x-rays have been measured. The gamma rays in Np have energies of 26.363, 33.199, 43.463, 59.568, 103, 113, 130, 159, 210, 270, 328, and 370 kev. The x-ray energies establish

Paul P. Day

1955-01-01

442

Electromagnetic Spectrum of Radium D  

Microsoft Academic Search

The electromagnetic spectrum of RaD has been studied by the proportional counter spectrometry technique. The work of the Curie Laboratory on the gamma-ray spectrum has been generally confirmed. However, the presumed K x-ray lines are of much lower intensity and occur at a lower energy than previously reported. The L x-ray intensity is 22 per hundred disintegrations, indicating 0.63 conversion

P. E. Damon; R. R. Edwards

1953-01-01

443

Electromagnetic compatibility in hospital corridors  

Microsoft Academic Search

The proposal that electromagnetic compatibility (EMC) in healthcare be fostered by using a free-space minimal-separation criterion between radio frequency (RF) sources of given power and medical devices of given immunity is evaluated. Electric fields within various corridors of a hospital were measured and the residuals of the fields from both slow-fade characteristics, and from free-space field predictions were computed. Measured

D. Davis; B. Segal; A. Cinquino; K. Hoege; R. Mastrocola; T. Pavlasek

1999-01-01

444

ELECTROMAGNETIC MODELING OF RETINAL PHOTORECEPTORS  

Microsoft Academic Search

Abstract—New electromagnetic models for the rods and,cones that are the,photoreceptors at,the,back,of the,retina are developed and simulated in order to explain the roles of dimension, geometrical structure, directional sensitivity and visual pigments of the photoreceptors in the reception of visible light. The rods and cones are modeled as uniform and quasi-tapered helical antennas, respectively. The results of the model study show

Cahit Canbay

2008-01-01

445

Computer animation of electromagnetic phenomena  

Microsoft Academic Search

A post-processing graphic package has been developed for the computer animation of 2D as well as 3D electromagnetic fields obtained from various finite element programs available at IGTE. The goal was to use relatively inexpensive and commonly available personal computers (e.g. 486\\/33 MHz systems or better) for this purpose because they have the further benefit of good transportability, advantageous at

K. Preis; I. Bardi; O. Biro; R. Hoschek; M. Mayr; U. Peterlini; K. R. Richter; I. Ticar

1995-01-01

446

Electromagnetic scattering in polarizable backgrounds  

Microsoft Academic Search

We develop a fully vectorial formalism for the investigation of electromagnetic scattering in polarizable backgrounds, i.e., where the scatterers are not in vacuum but situated in a medium with a dielectric permittivity different from unity. Our approach is based on the Green's tensor technique and the corresponding Green's tensors for two-dimensional ~2D! and three-dimensional ~3D! systems are developed. The analysis

Olivier J. F. Martin; Nicolas B. Piller

1998-01-01

447

Genetic algorithms in engineering electromagnetics  

Microsoft Academic Search

This paper presents a tutorial and overview of genetic algorithms for electromagnetic optimization. Genetic-algorithm (GA) optimizers are robust, stochastic search methods modeled on the concepts of natural selection and evolution. The relationship between traditional optimization techniques and the GA is discussed. Step-by-step implementation aspects of the GA are detailed, through an example with the objective of providing useful guidelines for

J. Michael Johnson; V. Rahmat-Samii

1997-01-01

448

Occupational exposure to electromagnetic fields and acute leukaemia: analysis of a case-control study  

PubMed Central

Aims: To investigate whether the risk of acute leukaemia among adults is associated with occupational exposure to electromagnetic fields. Methods: Probable occupational exposure to electromagnetic fields at higher than typical residential levels was investigated among 764 patients diagnosed with acute leukaemia during 1991–96 and 1510 sex and age matched controls. A job exposure matrix was applied to the self reported employment histories to determine whether or not a subject was exposed to electromagnetic fields. Risks were assessed using conditional logistic regression for a matched analysis. Results: Study subjects considered probably ever exposed to electromagnetic fields at work were not at increased risk of acute leukaemia compared to those considered never exposed. Generally, no associations were observed on stratification by sex, leukaemia subtype, number of years since exposure stopped, or occupation; there was no evidence of a dose-response effect using increasing number of years exposed. However, relative to women considered never exposed, a significant excess of acute lymphoblastic leukaemia was observed among women probably exposed to electromagnetic fields at work that remained increased irrespective of time prior to diagnosis or job ever held. Conclusion: This large population based case-control study found little evidence to support an association between occupational exposure to electromagnetic fields and acute leukaemia. While an excess of acute lymphoblastic leukaemia among women was observed, it is unlikely that occupational exposure to electromagnetic fields was responsible, given that increased risks remained during periods when exposure above background levels was improbable.

Willett, E; McKinney, P; Fear, N; Cartwright, R; Roman, E

2003-01-01

449

Electromagnetism on anisotropic fractal media  

NASA Astrophysics Data System (ADS)

Basic equations of electromagnetic fields in anisotropic fractal media are obtained using a dimensional regularization approach. First, a formulation based on product measures is shown to satisfy the four basic identities of the vector calculus. This allows a generalization of the Green-Gauss and Stokes theorems as well as the charge conservation equation on anisotropic fractals. Then, pursuing the conceptual approach, we derive the Faraday and Ampère laws for such fractal media, which, along with two auxiliary null-divergence conditions, effectively give the modified Maxwell equations. Proceeding on a separate track, we employ a variational principle for electromagnetic fields, appropriately adapted to fractal media, so as to independently derive the same forms of these two laws. It is next found that the parabolic (for a conducting medium) and the hyperbolic (for a dielectric medium) equations involve modified gradient operators, while the Poynting vector has the same form as in the non-fractal case. Finally, Maxwell's electromagnetic stress tensor is reformulated for fractal systems. In all the cases, the derived equations for fractal media depend explicitly on fractal dimensions in three different directions and reduce to conventional forms for continuous media with Euclidean geometries upon setting these each of dimensions equal to unity.

Ostoja-Starzewski, Martin

2013-04-01

450

Fabrication of electromagnetic micromirror array  

NASA Astrophysics Data System (ADS)

This paper describes the design, fabrication and experiments of a micromirror array driven by electromagnetic force for right angle beam reflection to the vertical direction of the substrate. The device was fabricated using aluminum surface micromachining combined with nickel electroplating. The micromirror has couple of torsional springs enough long for 45 degree rotation, which angular deflection is necessary for right angle beam reflection. Also micromirror has a magnetic material for electromagnetic operation, and it has a mechanical stopper for angular deflection control. The main structural material is evaporated aluminum, and magnetic material is electroplated nickel. Thick photoresist is used as a sacrificial layer, and it is removed by oxygen plasma process. Electromagnetic characteristics were measured to find that about 10kA/m magnetic field intensity is needed for 45 degrees angular deflection. 25V to approximately 50V clamping voltage is required for selectively operation between the array within the external magnetic field. The dynamic response measurement was fulfilled using He-Ne laser and position sensitive diode (PSD). The lapsed time to reach 45 degrees is less than 0.5ms. But upward spring bending prevents the stopper from touching the substrate, so some oscillations corresponding to natural response is observed.

Jang, YunHo; Kim, Yong-Kweon

2001-09-01

451

Coherent pump-probe spectroscopy in sodium vapor: From electromagnetically induced transparency to parametric amplification  

NASA Astrophysics Data System (ADS)

We have theoretically and experimentally investigated coherent pump-probe spectra for the 3S1/2-3P1/2 D1 transition of sodium atomic vapor. Probe transmission spectra in the presence of a coupling beam exhibit dramatic changes depending on experimental conditions. In the weak-excitation, low-atomic-density limit, the spectra are mainly characterized by electromagnetically induced transparency (EIT) and saturated absorption, but for the strong-excitation, high-density case, parametric amplification (PA) is dominant, featuring high probe gain and Stokes-wave generation. We have developed a theory that can explain these two seemingly totally different phenomena (EIT and PA) within the same theoretical framework by manipulating a few experimentally controllable parameters, and have successfully reproduced the observed spectra. Other than the main spectral features, many other interesting physical processes have been predicted and observed.

Takahashi, Ken-Ichi; Hayashi, Nobuhito; Kido, Hiroaki; Sugimura, Shota; Hombo, Naoya; Mitsunaga, Masaharu

2011-06-01

452

Coherent pump-probe spectroscopy in sodium vapor: From electromagnetically induced transparency to parametric amplification  

SciTech Connect

We have theoretically and experimentally investigated coherent pump-probe spectra for the 3S{sub 1/2}-3P{sub 1/2} D1 transition of sodium atomic vapor. Probe transmission spectra in the presence of a coupling beam exhibit dramatic changes depending on experimental conditions. In the weak-excitation, low-atomic-density limit, the spectra are mainly characterized by electromagnetically induced transparency (EIT) and saturated absorption, but for the strong-excitation, high-density case, parametric amplification (PA) is dominant, featuring high probe gain and Stokes-wave generation. We have developed a theory that can explain these two seemingly totally different phenomena (EIT and PA) within the same theoretical framework by manipulating a few experimentally controllable parameters, and have successfully reproduced the observed spectra. Other than the main spectral features, many other interesting physical processes have been predicted and observed.

Takahashi, Ken-ichi; Hayashi, Nobuhito; Kido, Hiroaki; Sugimura, Shota; Hombo, Naoya; Mitsunaga, Masaharu [Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto, 860-8555 (Japan)

2011-06-15

453

Electric and electromagnetic phenomena in meteor trails  

NASA Astrophysics Data System (ADS)

The present study examines experimental and theoretical investigations of electric and electromagnetic phenomena in meteor trails conducted in the past, and makes a general overview of the problem. It is concluded that the problem has yet to be developed on a serious theoretical level. All the research done in the 1960s is based on different approaches and, as a rule, does not contain mutual criticism and discussion. It can be considered proven that a meteor body acquires during ablation a positive stabilized charge with a potential of several volts. A quasi-hydrodynamic approach to kinetic equations for electron and ion motion in a meteor trail can be used to analyze the first stage of the formation of a meteor trail and to verify the charge separation concept.

Bronshten, V. A.

1991-04-01

454

Optical pumping-assisted electromagnetically induced transparency  

SciTech Connect

In this paper we report an observation of the two-photon absorption in a four-level system in hot {sup 87}Rb vapor based on the proposal of Harris and Yamamoto [Phys. Rev. Lett. 81, 3611 (1998)]. We show that this effect is reduced in hot atoms due to the non-Doppler-free nature of this scheme. Then we report a phenomenon that could be used in the same application of Harris and Yamamoto. The main result is a great enhancement of electromagnetically induced transparency (EIT) effect in hot {sup 87}Rb vapor caused by optical pumping. We find that when the single photon detuning is near zero the EIT signal is dramatically enhanced by an optical pumping field. More interestingly when the single photon detuning is larger the signal can be changed from a sharp Raman peak to a sharp EIT dip. The full width at half maximum of the peak and dip are narrow and subnatural.

Jiang Wei; Chen Qunfeng; Zhang Yongsheng; Guo, G.-C. [Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, 230026 (China)

2006-05-15

455

Superconducting Resonators with Parasitic Electromagnetic Environments  

NASA Astrophysics Data System (ADS)

Microwave losses in niobium superconducting resonators are investigated at milli-Kelvin temperatures and with low drive power. In addition to the well-known suppression of Q-factor that arises from coupling between the resonator and two-level defects in the dielectric substrate [1-4], we report strong dependence of the loaded Q-factor and resonance line-shape on the electromagnetic environment. Methods to suppress parasitic coupling between the resonator and its environment are demonstrated.[4pt] [1] Day, P.K. et al., Nature 425, 817-821 (2003).[0pt] [2] Wallraff, A. et. al., Nature 451, 162-167 (2004).[0pt] [3] Macha, P. et. al., Appl. Phys. Lett., 96, 062503 (2010).[0pt] [4] O'Connell, A.D. et. al., Appl. Phys. Lett., 92, 112903 (2008).

Hornibrook, John; Mitchell, Emma; Reilly, David

2012-02-01

456

Electromagnetic radiation from selected telecommunications systems  

SciTech Connect

The paper describes the instrumentation and measurement techniques used in a study of electromagnetic (EM) energy in radio transmission systems, and summarizes results obtained for high frequency (HF) radio, tropospheric scatter, earth-satellite, and microwave radio relay systems. Power density and electric field measurements were made at selected facilities, including antenna tower locations for point-to-point microwave radio equipment it was found that the maximum electric field strengths associated with HF radio systems in areas accessible to radio personnel was less than 36 V/m. The maximum power densities associated with tropospheric scatter systems, satellite communication earth stations and point-to-point microwave radio systems were less than 1 microwatt/sq cm. In some cases microwave radio rooms in high building floors showed maximum levels due to VHF and UHF transmitters of a few tens of microwatt/sq cm.

Petersen, R.C.

1980-01-01

457

Electromagnetic counterparts to black hole mergers  

NASA Astrophysics Data System (ADS)

During the final moments of a binary black hole (BH) merger, the gravitational wave (GW) luminosity of the system is greater than the combined electromagnetic (EM) output of the entire observable universe. However, the extremely weak coupling between GWs and ordinary matter makes these waves very difficult to detect directly. Fortunately, the inspiraling BH system will interact strongly—on a purely Newtonian level—with any surrounding material in the host galaxy, and this matter can in turn produce unique EM signals detectable at Earth. By identifying EM counterparts to GW sources, we will be able to study the host environments of the merging BHs, in turn greatly expanding the scientific yield of a mission like LISA. Here we present a comprehensive review of the recent literature on the subject of EM counterparts, as well as a discussion of the theoretical and observational advances required to fully realize the scientific potential of the field.

Schnittman, Jeremy D.

2011-05-01

458

Electromagnetically induced transparency in cold rubidium atoms  

SciTech Connect

We report experimental studies of electromagnetically induced transparency in {Lambda}-type and ladder-type atomic systems realized in {sup 87}Rb atoms cooled and confined in a magneto-optical trap. Complete transparency is observed in the {Lambda}-type system with a moderate coupling field. Comparison between the two systems reveals that at the line center of a weak probe transition, destructive interference occurs for the {Lambda}-type system, whereas constructive interference occurs for the ladder-type system. We discuss conditions of complete transparency in the {Lambda}-type system that contains hyperfine magnetic sublevels. Our experimental measurements for the two systems agree with theoretical calculations based on simple three-level {Lambda}-type and ladder-type models. {copyright} 2001 Optical Society of America

Yan, Min; Rickey, Edward G.; Zhu, Yifu

2001-08-01

459

Electromagnetic subsurface measurements  

NASA Astrophysics Data System (ADS)

In 1974, personnel at the U.S. Army Cold Regions Research and Engineering Laboratory (CRREL) began using an impulse radar system to profile accumulations of ice forms. The system was modified for effective use as a profiling system in a ground or airborne configuration, in certain high-noise environments. The system can penetrate fresh water and media with a high water content. Frazil and brash ice accumulations with approximately 50% water were profiled to a depth of 25 to 35 ft. As a result of the CRREL modifications, the system has found extensive and varied applications as a low-level remote sensing tool. Applications include profiling ice accumulations (including ice jams), river beds, sheet ice, permafrost, subsurface ice masses, river bank revetments through air-entrained water, snow covers, sea ice, icebergs, and peat bogs. Limited laboratory work has also shown that the impulse radar system may be able to detect oil and gas under sea ice. Selected applications and data are presented. Since it was used mainly for research, the CRREL system needs further development to make it useful to operational units. Additional development of hardware and software is recommended.

Dean, A. M., Jr.

1981-10-01

460

Time spectra of patent information  

Microsoft Academic Search

Information spectra are defined as intervals between equivalent information events. Their relations to negative binomial and negative polynomial distributions and urn models are explained. Basic properties of empirical information spectra from patent literature are shown and discussed in connection withHaitun's views on Z type information distributions,Sichel's GIGP model andTrofimenko's study on formation and decay of author groups.

M. Kunz

1987-01-01

461

Mutation spectra of complex environmental mixtures  

Microsoft Academic Search

Bioassay-directed chemical analysis of complex environmental mixtures has indicated that much of the genotoxic activity of mixtures is due to the presence of one or a few classes or chemicals within the mixture. We have extended this observation to the molecular level by using colony probe hybridization and PCR\\/DNA sequence analysis to determine the mutation spectra of â¼8,000 revertants induced

DeMarini

1997-01-01

462

Experimental evaluation of the twofold electromagnetic enhancement theory of surface-enhanced resonance Raman scattering  

SciTech Connect

We examined an electromagnetic (EM) theory of surface-enhanced resonance Raman scattering (SERRS) using single Ag nanoaggregates. The SERRS-EM theory is characterized by twofold EM enhancement induced by the coupling of plasmon resonance with both excitation and emission of Raman scattering plus fluorescence. The total emission cross-section spectra of enhanced Raman scattering and enhanced fluorescence were calculated using the following parameters: the spectrum of enhancement factor induced by plasmon resonance, resonance Raman scattering overlapped with fluorescence, and excitation wavelengths. The calculations well agreed with experimental total emission cross-section spectra, thus providing strong indications that the SERRS-EM theory is quantitatively correct.

Yoshida, Ken-ichi [Department of Chemistry, School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo 669-1337 (Japan); Nano-Bioanalysis Team, Health Technology Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Takamatsu, Kagawa 761-0395 (Japan); Itoh, Tamitake; Biju, Vasudevanpillai; Ishikawa, Mitsuru [Nano-Bioanalysis Team, Health Technology Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Takamatsu, Kagawa 761-0395 (Japan); Ozaki, Yukihiro [Department of Chemistry, School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo 669-1337 (Japan)

2009-02-15

463

Emission of electromagnetic radiation by coherent vibrational waves in stimulated Raman scattering  

NASA Astrophysics Data System (ADS)

Electromagnetic radiation is emitted by the vibrational and collective modes of an opaque solid as the result of impulsive stimulated Raman scattering. Raman scattering of near-infrared femtosecond laser pulses produces coherent longitudinal optical phonon and plasmon oscillations in the semiconductor InSb. These oscillations radiate into free space at THz frequencies and are directly detected. The THz spectra exhibit features consistent with Raman selection rules including interference of allowed and forbidden Raman scattering.

Hasselbeck, Michael P.; Schlie, L. A.; Stalnaker, D.

2004-07-01

464

Propagation characteristics of ESD-induced electromagnetic pulses measured using optical E-field sensor  

Microsoft Academic Search

This paper describes the propagation characteristics of electromagnetic pulses induced by electrostatic discharge (ESD) in the far field. ESD energy spectra measured with an electric field sensor using a Mach-Zehnder interferometer are analyzed for the frequency band DC-1 GHz by short-time Fourier transform (STFT). Analytical results show that ESD energy in high frequency band (100 MHz-1 GHz) decrease more rapidly

K. Tajima; M. Masugi; N. Kuwabara

1999-01-01

465

Electromagnetic Effects in SDF Explosions  

SciTech Connect

The notion of high ion and electron concentrations in the detonation of aluminized explosive mixtures has aroused some interest in electro-magnetic effects that the SDF charges might generate when detonated. Motivated by this interest we have started to investigate whether significant electro-magnetic effects show up in our small-scale experiments. However, the design of instrumentation for this purpose is far from straightforward, since there are a number of open questions. Thus the main aim of the feasibility tests is to find - if possible - a simple and reliable method that can be used as a diagnostic tool for electro-magnetic effects. SDF charges with a 0.5-g PETN booster and a filling of 1 g aluminum flakes have been investigated in three barometric bomb calorimeters with volumes ranging from 6.3 l to of 6.6 l. Though similar in volume, the barometric bombs differed in the length-to-diameter ratio. The tests were carried out with the bombs filled with either air or nitrogen at ambient pressure. The comparison of the test in air to those in nitrogen shows that the combustion of TNT detonation products or aluminum generates a substantial increase of the quasi-steady overpressure in the bombs. Repeated tests in the same configuration resulted in some scatter of the experimental results. The most likely reason is that the aluminum combustion in most or all cases is incomplete and that the amount of aluminum actually burned varies from test to test. The mass fraction burned apparently decreases with increasing aspect ratio L/D. Thus an L/D-ratio of about 1 is optimal for the performance of shock-dispersed-fuel combustion. However, at an L/D-ratio of about 5 the combustion still yields appreciable overpressure in excess of the detonation. For a multi-burst scenario in a tunnel environment with a number of SDF charges distributed along a tunnel section a spacing of 5 tunnel diameter and a fuel-specific volume of around 7 l/g might provide an acceptable compromise between optimizing the combustion performance and keeping the number of elementary charges low. Further tests in a barometric bomb calorimeter of 21.2 l volume were performed with four types of aluminum. The mass fraction burned in this case appeared to depend on the morphology of the aluminum particles. Flake aluminum exhibited a better performance than granulated aluminum with particle sizes ranging from below 25 {micro}m to 125 {micro}m for the coarsest material. In addition, a feasibility study on electro-magnetic effects from SDF charges detonated in a tunnel has been performed. A method was developed to measure the local, unsteady electro-conductivity in the detonation/combustion products cloud. This method proved to yield reproducible results. A variety of methods were tested with regard to probing electro-magnetic pulses from the detonation of SDF charges. The results showed little reproducibility and were small compared to the effect from pulsed high voltage discharges of comparatively small energy (around 32 J). Thus either no significant electromagnetic pulse is generated in our small-scale tests or the tested techniques have to be discarded as too insensitive or too limited in bandwidth to detect possibly very high frequency electro-magnetic disturbances.

Reichenbach, H; Neuwald, P; Kuhl, A L

2010-02-12

466

Applied Computational Electromagnetics Society Journal. Computer Applications in Electromagnetics Education. Special Issue. Volume 8, Number 1.  

National Technical Information Service (NTIS)

The Applied Computational Electromagnetics Society Journal is devoted to the exchange of information in computational electromagnetics, to the advancement of the state-of-the-art, and to the promotion of related technical activities. A primary objective o...

M. Iskander

1993-01-01

467

Statistical theory of electromagnetic weak turbulence  

SciTech Connect

The weak turbulence theory as commonly found in the literature employs electrostatic approximation and is applicable to unmagnetized plasmas only. To this date, fully electromagnetic generalization of the existing weak turbulence theory based upon statistical mechanical approach remains largely incomplete. Instead, electromagnetic effects are incorporated into the weak turbulence formalism by means of the semiclassical approach. The present paper reformulates the fully electromagnetic weak turbulence theory from classical statistical mechanical (i.e., the Klimontovich) approach.

Yoon, Peter H. [Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742-2431 (United States)

2006-02-15

468

Electromagnetic wave in a relativistic magnetized plasma  

SciTech Connect

Results are presented from a theoretical investigation of the dispersion properties of a relativistic plasma in which an electromagnetic wave propagates along an external magnetic field. The dielectric tensor in integral form is simplified by separating its imaginary and real parts. A dispersion relation for an electromagnetic wave is obtained that makes it possible to analyze the dispersion and collisionless damping of electromagnetic perturbations over a broad parameter range for both nonrelativistic and ultrarelativistic plasmas.

Krasovitskiy, V. B. [Russian Academy of Sciences, Keldysh Institute of Applied Mathematics (Russian Federation)

2009-12-15

469

Electromagnetic wave scattering by Schwarzschild black holes.  

PubMed

We analyze the scattering of a planar monochromatic electromagnetic wave incident upon a Schwarzschild black hole. We obtain accurate numerical results from the partial wave method for the electromagnetic scattering cross section and show that they are in excellent agreement with analytical approximations. The scattering of electromagnetic waves is compared with the scattering of scalar, spinor, and gravitational waves. We present a unified picture of the scattering of all massless fields for the first time. PMID:19658920

Crispino, Luís C B; Dolan, Sam R; Oliveira, Ednilton S

2009-06-11

470

Modeling of Nonlaminated Electromagnetic Suspension Systems  

Microsoft Academic Search

Eddy currents induced within nonlaminated electromagnetic actuators by time-varying magnetic fields have a strong effect on the dynamics and control of electromagnetic suspension systems. This paper examines the modeling of these suspension systems and resolves two important problems: 1) the effect of time-varying flotor position on electromagnetic force production and 2) the proper manner in which to model voltage-mode operation

Lei Zhu; Carl R. Knospe

2010-01-01

471

Electromagnetic noise in McElroy Mine  

Microsoft Academic Search

Two different techniques were used to make measurements of the absolute value of electromagnetic noise in and above an operating coal mine. McElroy Mine, located near Moundsville, West Virginia. A 300-volt-dc and 480-volt-ac machinery was measured to see the electromagnetic environment it created. One technique measures noise over the entire electromagnetic spectrum of interest for brief time periods. It is

M. Kanda; J. W. Adams; W. D. Bensema

1974-01-01

472

Molecular Expressions: Science, Optics & You: Electromagnetic Radiation  

NSDL National Science Digital Library

This item is an interactive Java simulation on electromagnetic radiation, the family of wave-like phenomena which includes visible light. Users control amplitude and wavelength to explore how electromagnetic waves are propagated. Included is a detailed text tutorial. This item is part of a larger collection of reference materials and simulations on electricity and magnetism. See Related Materials on this page for links to additional materials by these authors on electromagnetic radiation.

Davidson, Michael; Abramowitz, Mortimer; Parry-Hill, Matthew J.

2008-08-21

473

An electromagnetic analogue of gravitational wave memory  

NASA Astrophysics Data System (ADS)

We present an electromagnetic analogue of gravitational wave memory. That is, we consider what change has occurred to a detector of electromagnetic radiation after the wave has passed. Rather than a distortion in the detector, as occurs in the gravitational wave case, we find a residual velocity (a ‘kick’) to the charges in the detector. In analogy with the two types of gravitational wave memory (‘ordinary’ and ‘nonlinear’) we find two types of electromagnetic kick.

Bieri, Lydia; Garfinkle, David

2013-10-01

474

Constraint propagation through electromagnetic interaction topologies  

Microsoft Academic Search

The effects of electromagnetic interactions in electrical systems are of concern because of the increasing susceptibility of system components. Heuristic methods are used by engineers to solve electromagnetic interaction problems. An approximate symbolic knowledge representation of a single emitter\\/path\\/susceptor problem has been described. In this paper the approximate single emitter\\/path\\/susceptor attributes are distributed throughout the electromagnetic topology of a complex

Joe Lovetri; Darin P. W. Graham

1990-01-01

475

MUSES: multi-sensor soil electromagnetic sounding  

NASA Astrophysics Data System (ADS)

The authors describe the performance of a multi-sensor package designed to measure the electromagnetic properties of the subsurface during future landing missions to Mars. The package consists of a soil dielectric spectroscopy probe (SDSP), a ground penetrating radar (GPR) and a time domain electromagnetic measurement (TDEM) system that, using different methods, estimate the electromagnetic properties of the shallow subsurface at different depths (0- 100 m). A data fusion approach is considered to improve the reliability and accuracy of the measurements.

Vannaroni, G.; Pettinelli, E.; Ottonello, C.; Cereti, A.; Della Monica, G.; Del Vento, D.; Di Lellis, A. M.; Di Maio, R.; Filippini, R.; Galli, A.; Menghini, A.; Orosei, R.; Orsini, S.; Pagnan, S.; Paolucci, F.; Pisani, A. R.; Schettini, G.; Storini, M.; Tacconi, G.

2004-01-01

476

An investigation of electromagnetic response of composite polymer materials containing carbon nanostructures within the range of frequencies 10 MHz - 1.1 THz  

NASA Astrophysics Data System (ADS)

Electromagnetic characteristics of composite polymer materials based on multilayer carbon nanotubes (MCNTs) and nano-onion carbon structures in a polymethylmethacrylate (PMMA) matrix are investigated. The purpose is to identify a functional relationship between the size, kind, type of processing, concentration of nanotubes and electromagnetic characteristics of composite materials within the frequency range 10 MHz - 1.1 THz. Use is made of the coaxial waveguide, resonator, and quasi-optical methods. The spectra of reflection and transmission coefficients are reported. The composite materials based on carbon nanostructures are shown to actively interact with electromagnetic radiation in a wide range of frequencies.

Suslyaev, V. I.; Kuznetsov, V. L.; Zhuravlev, V. A.; Mazov, I. N.; Korovin, E. Yu.; Moseenkov, S. I.; Dorozhkin, K. V.

2013-01-01

477

All-optical switching and routing based on an electromagnetically induced absorption grating.  

PubMed

An electromagnetically induced absorption grating is formed in a three-level atomic vapor under the condition of electromagnetically induced transparency in which the strong coupling beam is replaced by a standing wave. The transmission and reflection behaviors of the weak probe beam are greatly modified at certain frequencies near the two-photon resonance. An all-optical two-port signal router-all-optical switch is demonstrated. PMID:15832910

Brown, Andy W; Xiao, Min

2005-04-01

478

Broadband electromagnetic cloaking of long cylindrical objects.  

PubMed

Electromagnetic cloaks are devices that make objects undetectable for probing with electromagnetic waves. The known realizations of transformational-optics cloaks require materials with exotic electromagnetic properties and offer only limited performance in narrow frequency bands. Here, we demonstrate a wideband and low-loss cloak whose operation is not based on the use of exotic electromagnetic materials, which are inevitably dispersive and lossy. Instead, we use a simple structure made of metal layers. In this Letter, we present an experimental demonstration of cloaking for microwaves and simulation results for cloaking in the visible range. PMID:19792314

Tretyakov, Sergei; Alitalo, Pekka; Luukkonen, Olli; Simovski, Constantin

2009-09-03

479

Detection of electromagnetic waves using MEMS antennas  

SciTech Connect

We describe the design, fabrication and characterization of simple micromechanical structures that are capable of sensing static electric time varying electromagnetic fields. Time varying electric field sensing is usually achieved using an electromagnetic antenna and a receiver. However, these antenna-based approaches do not exhibit high sensitivity over a broad frequency (or wavelength) range. An important aspect of the present work is that, in contrast to traditional antennas, the dimensions of these micromechanical oscillators can be much smaller than the wavelength of the electromagnetic wave. We characterized the fabricated micromechanical oscillators by measuring their responses to time varying electric and electromagnetic fields.

Lavrik, Nickolay V [ORNL; Tobin, [Oak Ridge National Laboratory (ORNL); Bowland, Landon T [ORNL

2011-01-01

480

Electromagnetic compatibility of nuclear power plants  

SciTech Connect

Lately, there has been a mounting concern about the electromagnetic compatibility of nuclear-power-plant systems mainly because of the effects due to the nuclear electromagnetic pulse, and also because of the introduction of more-sophisticated and, therefore, more-susceptible solid-state devices into the plants. Questions have been raised about the adequacy of solid-state-device protection against plant electromagnetic-interference sources and transients due to the nuclear electromagnetic pulse. In this paper, the author briefly reviews the environment, and the coupling, susceptibility, and vulnerability assessment issues of commercial nuclear power plants.

Cabayan, H.S.

1983-01-01

481

Libration Controller of Electromagnetic Vehicle Vibrator  

NASA Astrophysics Data System (ADS)

Electromagnetic Vehicle Vibrator is a non-explosive seismic source, for high resolution detection of underground information, which is used for mineral resources reconnaissance and detecting special target underground abroadly. The work principle comes from Chirp radar technique, the main task is sending Chirp signal with strict controlled parameter to underground. The Chirp signal produced by Electromagnetic Vehicle Vibrator is sent to underground by power amplification and