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1

The Teaching of Electromagnetism at University Level  

ERIC Educational Resources Information Center

Discusses different kinds of material presentation in the teaching of electromagnetism at the university level, including three "classical" approaches and the Keller personalized proctorial system. Indicates that a general introduction to generators and motors may be useful in an electromagnetism course. (CC)

Houldin, J. E.

1974-01-01

2

HOT ELECTROMAGNETIC OUTFLOWS. I. ACCELERATION AND SPECTRA  

SciTech Connect

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 [Department of Physics, University of Toronto, 60 St. George St., Toronto, ON M5S 1A7 (Canada); Thompson, Christopher [Canadian Institute for Theoretical Astrophysics, 60 St. George St., Toronto, ON M5S 3H8 (Canada)

2013-04-20

3

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

4

Electromagnetic Interference in Wireless Communications: Behavioral-Level Simulation  

E-print Network

Electromagnetic Interference in Wireless Communications: Behavioral-Level Simulation Approach in electromagnetic interference (EMI) modeling and simulation for modern and future wireless communication systems and networks taking into account nonlinear interference effects are discussed in this paper. It is emphasized

Loyka, Sergey

5

Core-level spectra from graphene  

NASA Astrophysics Data System (ADS)

We calculate core-level spectra for pristine and doped free-standing graphene sheets. Instructions for how to perform the calculations are given in detail. Although pristine graphene is not metallic the core-level spectrum presents low-energy tailing which is characteristic of metallic systems. The peak shapes vary with doping level in a characteristic way. The spectra are compared to experiments and show good agreement. We compare to two different pristine samples and to one doped sample. The pristine samples are one with quasi-free-standing epitaxial graphene on SiC obtained by hydrogen intercalation and one with a suspended graphene sheet. The doped sample is a gold supported graphene sheet. The gold substrate acts as an acceptor so the graphene sheet gets p doped.

Sernelius, Bo E.

2015-01-01

6

New downshifted maximum in stimulated electromagnetic emission spectra  

NASA Astrophysics Data System (ADS)

A new spectral maximum in spectra of stimulated electromagnetic emission of the ionosphere (SEE, [1]) was detected in experiments at the SURA facility in 2008 for the pump frequencies f0 4.4-4.5 MHz, most stably for f0 = 4.3 MHz, the lowest possible pump frequency at the SURA facility. The new maximum is situated at frequency shifts ?f -6 kHz from the pump wave frequency f0 , ?f = fSEE - f0 , somewhat closer to the f0 than the well known [2,3] Downshifted Maximum in the SEE spectrum at ?f -9 kHz. The detection and detailed study of the new feature (which we tentatively called the New Downshifted Maximum, NDM) became possible due to high frequency resolution in spectral analysis. The following properties of the NDM are established. (i) The NDM appears in the SEE spectra simultaneously with the DM and UM features after the pump turn on (recall that the less intensive Upshifted Maximum, UM, is situated at ?f +(6-8) kHz [2,3]). The NDM can't be attributed to 1 DM [4] or Narrow Continuum Maximum (NCM, 2 [5]) SEE features, as well as to splitted DM near gyroharmonics [2]. (ii) The NDM is observed as prominent feature for maximum pump power of the SURA facility P ? 120 MW ERP, for which the DM is almost covered by the Broad Continuum SEE feature [2,3]. For P ˜ 30-60 MW ERP the DM and NDM have comparable intensities. For the lesser pump power the DM prevails in the SEE spectrum, while the NDM becomes invisible being covered by the thermal Narrow Continuum feature [2]. (iii) The NDM is exactly symmetrical for the UM relatively to f0 when the former one is observed, although the UM frequency offset increases up to ?fUM ? +9 kHz with a decrease of the pump power up to P ? 4 MW ERP. The DM formation in the SEE spectrum is attributed to a three-wave interaction between the upper and lower hybrid waves in the ionosphere, and the lower hybrid frequency ( 7 kHz) determines the frequency offset of the DM high frequency flank [2,6]. The detection of the NDM with lesser |?fNDM | ˜ 6 kHz and observed values ?fDM ˜ -20 kHz at f0 ˜ 9300 kHz confirm the experimentally observed dependence |?fDM,UM | 2f0 · 10-3 [3,4] and give a hint to a possible competition of different mechanisms of the SEE generation in the DM and UM frequency range [4]. The work is supported by RFBR grants 10-02-00642, 09-02-01150 and Federal Special-purpose Program "Scientific and pedagogical personnel of innovative Russia". 1. Thide B. et al., Phys. Rev. Lett., 1982, 49, pp. 1561-1564. 2. Leyser T.B., Space Sci. Rev., 2001, 98, 3-4, pp. 223-328. 3. Sergeev E.N. et al., J. Adv. in Space Res., 2006, 38, 11, pp. 2518-2526. 4. Stubbe P. et al., J.Geophys. Res., 1984, 89, pp.7523-7536. 5. Thide B. et al., Phys. Rev. Lett., 2005, 95, 25, p. 255002. 6. Shvarts M.M. et al., JASTP, 1997, 59, 18, pp.2421-2429.

Sergeev, Evgeny; Grach, Savely

7

Noise level and ultrasound spectra during burring.  

PubMed

The aim of this study was to evaluate the noise spectra of current dentistry equipment during normal work at the dental clinic and in the laboratory. In the study, noise was measured during the dental treatment of seven patients at a dental clinic and also in the acoustics laboratory, where working noise was simulated by drilling a polyacetal plate. All samples were analyzed in audible and ultrasonic areas in the one-third octave bands of 20-80,000 Hz. The measuring instruments used were B&K 4135 microphones, B&K 2633 preamplifiers, the B&K 2811 multiplexer, and the B&K 2133 real-time analyzer with the ZT 0318 high-frequency expansion unit. In the in situ measurements, the A-weighted sound pressure level was occasionally over 85 dB(A), and the equivalent continuous A-weighted sound pressure level, L(Aeq), was 76 dB(A). The noise level was most powerful in the one-third octave band of 40,000 Hz, where it was 74 dB. In laboratory measurements, the noise levels of the air-turbine and the micromotor hand pieces (n=16) were also most powerful in the one-third octave band of 40,000 Hz, where they were 80-89 dB. The L(Aeq) of the different micromotor handpieces (n=6) varied between 76 dB(A) and 77 dB(A), and the L(Aeq) of the turbine hand pieces (n=10) varied between 77 dB(A) and 82 dB(A). The noise of the drills is most powerful in the high frequencies, so using hearing protectors, it is possible that speech communication improves because the protectors attenuate high frequencies more than low frequencies. The very light protectors give sufficient protection against the drilling noise. PMID:12271344

Sorainen, E; Rytkönen, E

2002-09-01

8

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. PMID:24096943

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

2013-01-01

9

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

10

The Teaching of Electromagnetic Induction at Sixth Form Level  

ERIC Educational Resources Information Center

Presents some ideas about teaching electromagnetic induction at sixth form level, including educational objectives, learning difficulties, syllabus requirements, selection of unit system, and sequence of material presentation. Suggests the Education Group of the Institute of Physics hold further discussions on these aspects before including the…

Archenhold, W. F.

1974-01-01

11

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

12

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

13

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

14

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.

15

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

16

Identifying New Fe I Levels from Stellar Spectra  

NASA Astrophysics Data System (ADS)

The spectrum of the Fe I atom is critical to many areas of astrophysics and beyond. Measurements of the energies of its high-lying levels remain woefully incomplete, however, despite extensive laboratory and solar analysis. Here we discuss work by Peterson & Kurucz (2014, ApJS, in press) to identify such levels using high-resolution archival absorption-line ultraviolet and optical spectra of stars, whose warm temperatures favor moderate Fe I excitation. To date this analysis has provided the upper energies of 66 Fe I levels. Many are of higher excitation than is accessible to laboratory experiments; several exceed the Fe I ionization energy. These levels provide new identifications for over two thousand potentially detectable lines. We describe and illustrate our method, which is based on matching the strengths and positions of unidentified spectral features to the lines sharing a particular upper level in Kurucz's semi-empirical calculations. We also highlight the improvements these new identifications bring to the determination of the abundances of trace elements in individual stars, and to the ability of calculations of cool stellar spectra to match low-resolution observations of stars and old stellar systems.

Peterson, Ruth; Kurucz, Robert L.

2015-01-01

17

Shape reconstruction in 3D electromagnetic induction tomography using a level set technique  

E-print Network

Shape reconstruction in 3D electromagnetic induction tomography using a level set technique O. Dorn, Canada Abstract We present a novel shape reconstruction technique for 3D low frequency electromagnetic induction tomography which uses a level set representation of the shapes. An efficient ad- joint scheme

Ascher, Uri M.

18

Electromagnets  

NSDL National Science Digital Library

This is an activity about the properties of electromagnets, which is a crucial underpinning for understanding how magnetic fields are generated in nature, in the surface of the Sun, and in the interior of Earth. Learners will create an electromagnet by letting an electric current flow through a wire to generate a magnetic field, which is then detected using a compass. This activity requires a thin insulated wire, pencil, battery, compass and paper clips. This is Activity 2 of the Magnetism and Electromagnetism teachers guide.

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

Resonant Spectra of Malignant Breast Cancer Tumors Using the Three-Dimensional Electromagnetic Fast Multipole Model. Part 1  

NASA Technical Reports Server (NTRS)

An intensive numerical study for the resonance scattering of malignant breast cancer tumors is presented. The rigorous three-dimensional electromagnetic model, based on the equivalence theorem, is used to obtain the induced electric and magnetic currents on the breast and tumor surfaces. The results show that a non-spherical malignant tumor can be characterized based its spectra regardless of its orientation, the incident polarization, or the incident or scattered directions. The tumor's spectra depend solely on its physical characteristics (i.e., the shape and the electrical properties), however, their locations are not functions of its burial depth. This work provides a useful guidance to select the appropriate frequency range for the tumor's size.

El-Shenawee, Magda

2003-01-01

21

Spectra  

NSDL National Science Digital Library

Learners construct a spectroscope out of a shoe box or mailing tube, diffraction grating, and other simple materials. They then use their spectroscope to observe spectra, the colors that make up light. Learners compare the spectra of various light sources. Use this activity to introduce learners to basic principles of light and color. Also, look at a related page about auroras to understand how distinguishing spectra of different atoms helps scientists understand the universe.

Exploratorium, The

2012-06-26

22

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

23

Electromagnetically induced transparency and dark fluorescence in a cascade three-level diatomic lithium system  

SciTech Connect

Following our previous brief report [Phys. Rev. Lett. 88, 173003 (2002)], we report here a detailed study of electromagnetically induced transparency (EIT) and dark fluorescence in a cascade three-level diatomic lithium system using optical-optical double resonance (OODR) spectroscopy for both resonance and off resonance coupling. When a strong coupling laser couples the intermediate state A {sup 1}{sigma}{sub u}{sup +}(v=13,J=14) to the upper state G {sup 1}{pi}{sub g}(v=11,J=14) of {sup 7}Li{sub 2}, the fluorescence from both A {sup 1}{sigma}{sub u}{sup +} and G {sup 1}{pi}{sub g} states was drastically reduced as the weak probe laser was tuned through the resonance transition between the ground state X {sup 1}{sigma}{sub g}{sup +}(v=4,J=15) and the excited state A {sup 1}{sigma}{sub u}{sup +}(v=13,J=14). The strong coupling laser makes an optically thick medium transparent for the probe transition. In addition, the fact that fluorescence from the upper state G {sup 1}{pi}{sub g}(v=11,J=14) was also dark when both lasers were tuned at resonance implies that the molecules were trapped in the ground state. We used density matrix methods to simulate the response of an open molecular three-level system to the action of a strong coupling field and a weak probe field. The analytical solutions were obtained under the steady-state condition. We have incorporated the magnetic sublevel (M) degeneracy of the rotational levels in the line shape analysis and report |M| dependent line shape splitting. Our theoretical calculations are in excellent agreement with the observed fluorescence spectra. We show that the coherence is remarkably preserved even when the coupling field was detuned far from the resonance.

Qi Jianbing [Department of Physics and Astronomy, Penn State Berks, Tulpehocken Road, P.O. Box 7009, Reading, Pennsylvania 19610 (United States); Lyyra, A. Marjatta [Physics Department, Temple University, Philadelphia, Pennsylvania 19112 (United States)

2006-04-15

24

Electromagnetically induced transparency and dark fluorescence in a cascade three-level Lithium molecule  

E-print Network

We observed electromagnetically induced transparency (EIT) and dark fluorescence in a cascade three-level diatomic Lithium system using Optical-Optical Double Resonance (OODR) spectroscopy. When a strong coupling laser couples the intermediate state $A^{1}\\Sigma^{+}_{u}(v=13, J=14)$ to the upper state $G^{1}\\Pi_{g}(v=11, J=14)$ of $^7Li_2$, the fluorescence from both $A^{1}\\Sigma^{+}_{u}$ and $G^{1}\\Pi_{g}$ states was drastically reduced as the weak probe laser was tuned through the resonance transition between the ground state $X^{1}\\Sigma^{+}_{g}(v=4, J=15)$ and the excited state $A^{1}\\Sigma^{+}_{u}(v=13, J=14)$. The strong coupling laser makes an optically thick medium transparent for the probe transition. In addition, The fact that fluorescence from the upper state $G^{1}\\Pi_{g}(v=11, J=14)$ was also dark when both lasers were tuned at resonance implies that the molecules were trapped in the ground state. We used density matrix methods to simulate the response of an open molecular three-level system to the action of a strong coupling field and a weak probe field. The analytical solutions were obtained under the steady-state condition. We have incorporated the magnetic sublevel (M) degeneracy of the rotational levels in the lineshape analysis and report $|M|$ dependent lineshape splitting. The theoretical calculations are in excellent agreement with the observed fluorescence spectra. We show that the coherence is remarkably preserved even when the coupling field was detuned far from the resonance.

Jianbing Qi; A. Marjatta Lyyra

2005-10-28

25

Surface-enhanced Raman scattering spectra of adsorbates on Cu2O nanospheres: charge-transfer and electromagnetic enhancement  

NASA Astrophysics Data System (ADS)

Surface-enhanced Raman scattering (SERS) spectra of 4-mercaptobenzoic acid (4-MBA) have been investigated on the surface of Cu2O nanospheres. The SERS signals were believed to originate from the static chemical enhancement, resonant chemical enhancement and electromagnetic enhancement. The coupling between the adsorbates and the semiconductor, evidenced by the shift in absorption spectrum of modified Cu2O and the enhancement of non-totally symmetric modes of the 4-MBA and 4-mercaptopyridine (4-MPY) molecules, were invoked to explain the experimental results. Furthermore, simulations were employed to investigate the nature of the enhancement mechanisms operative between the molecules and the semiconductor. Density functional theory (DFT) calculations suggested a charge transfer (CT) transition process between the molecules and the Cu2O nanospheres. Three-dimensional finite-difference time domain (3D-FDTD) simulations were conducted to map out the electromagnetic field around the Cu2O nanospheres. The experimental and simulation results have revealed the promise of the Cu2O nanospheres as a good SERS substrate and the prospect of using the SERS substrate as a valuable tool for in situ investigation and assay of the adsorption behavior on semiconductor surfaces.Surface-enhanced Raman scattering (SERS) spectra of 4-mercaptobenzoic acid (4-MBA) have been investigated on the surface of Cu2O nanospheres. The SERS signals were believed to originate from the static chemical enhancement, resonant chemical enhancement and electromagnetic enhancement. The coupling between the adsorbates and the semiconductor, evidenced by the shift in absorption spectrum of modified Cu2O and the enhancement of non-totally symmetric modes of the 4-MBA and 4-mercaptopyridine (4-MPY) molecules, were invoked to explain the experimental results. Furthermore, simulations were employed to investigate the nature of the enhancement mechanisms operative between the molecules and the semiconductor. Density functional theory (DFT) calculations suggested a charge transfer (CT) transition process between the molecules and the Cu2O nanospheres. Three-dimensional finite-difference time domain (3D-FDTD) simulations were conducted to map out the electromagnetic field around the Cu2O nanospheres. The experimental and simulation results have revealed the promise of the Cu2O nanospheres as a good SERS substrate and the prospect of using the SERS substrate as a valuable tool for in situ investigation and assay of the adsorption behavior on semiconductor surfaces. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr33502j

Jiang, Li; You, Tingting; Yin, Penggang; Shang, Yang; Zhang, Dongfeng; Guo, Lin; Yang, Shihe

2013-03-01

26

Electromagnetic field stimulation of biosynthesis: changes in c- myc transcript levels during continuous and intermittent exposures  

Microsoft Academic Search

We studied the effects of continuous and single limited exposures of HL60 cells to 60 Hz electromagnetic (EM) fields. Results showed an increase in transcript levels for c-myc peaks after 20 min of exposure, but the rate of return of this transcript to control levels is dependent upon whether the field is left on or turned off after 20 min.

H. Lin; M. Blank; M. Jin; R. Goodman

1996-01-01

27

The Two-Level Model on Absorption Spectra of Oxyhemo- and Neuroglobin  

NASA Astrophysics Data System (ADS)

The absorption spectra of deoxyhemoglobin and oxyneuroglobin has been examined. The well-known two-level model has been used to study the absorption spectra. The model has been verified by experemental data for heomoglobin and neuroglobin, that gives good fittings. The discussion on the obtained results leads to further works

Thi Thao, To; Bernad, Sophie; Derrien, Valerie; Thuy Anh, Chu; Lan, Nguyen Tri; Viet, Nguyen Ai

2014-09-01

28

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

2009-01-16

29

INTERPRETATION OF LOW RESOLUTION MASS SPECTRA FOR LEVEL 1 ANALYSIS OF ENVIRONMENTAL MIXTURES  

EPA Science Inventory

The report gives guidelines for interpreting the low resolution mass spectra (LRMS) of complex chemical mixtures, within the context of the EPA Level 1 Environmental Assessment Program. It discusses the principles underlying direct mass spectrometric analysis of complex mixtures,...

30

March 17 - 19, 2004: Low-level processing of proteomics spectra, Kevin Coombes  

Cancer.gov

Low-level processing of proteomics spectra Kevin Coombes Department of Biostatistics and Applied Mathematics UT M.D.Anderson Cancer Center Overview z Background and motivation z Description of data set for methodology development and testing z Wavelet

31

Electromagnetically Induced Transparency using six level atoms doped in the crystalline medium  

E-print Network

Using the density matrix theory of interaction between light and matter, and relevant parameters of the relaxation rates for a six-level model, we have shown theoretically the possibility of realizing Electromagnetically Induced Transparency (EIT) and Slow Light effects in Pr(+3 ion) doped YSO crystal. In addition, we have presented a simplified method to analyse EIT effect in such a six level atomic system. Finally, we have demonstrated results of numerical calculation and have compared them with experimental measurements reported recently.

Hassan Kaatuzian; Sina Mehrabadi; Ahmad Ajdarzadeh Oskouei

2005-11-21

32

Survey of ambient electromagnetic and radio-frequency interference levels in nuclear power plants  

SciTech Connect

This document reports the results of a survey of ambient electromagnetic conditions in representative nuclear power plants. The U.S. Nuclear Regulatory Commission (NRC) Office of Nuclear Regulatory Research engaged the Oak Ridge National Laboratory (ORNL) to perform these measurements to characterize the electromagnetic interference (EMI) and radio-frequency interference (RFI) levels that can be expected in nuclear power plant environments. This survey is the first of its kind, being based on long-term unattended observations. The data presented in this report were measured at eight different nuclear units and required 14 months to collect. A representative sampling of power plant conditions (reactor type, operating mode, site location) monitored over extended observation periods (up to 5 weeks) were selected to more completely determine the characteristic electromagnetic environment for nuclear power plants. Radiated electric fields were measured over the frequency range of 5 MHz to 8 GHz. Radiated magnetic fields and conducted EMI events were measured over the frequency range of 305 Hz to 5 MHz. Highest strength observations of the electromagnetic ambient environment across all measurement conditions at each site provide frequency-dependent profiles for EMI/RFI levels in nuclear power plants.

Kercel, S.W.; Moore, M.R.; Blakeman, E.D.; Ewing, P.D.; Wood, R.T.

1996-11-01

33

Four-wave mixing in a three-level bichromatic electromagnetically induced transparency system  

SciTech Connect

We investigate the four-wave mixing (FWM) phenomenon in a three-level bichromatic electromagnetically induced transparency system. Theoretical results predict that the FWM will exhibit a multipeak structure under bichromatic coupling fields. The stronger the coupling fields are, the more FWM the peaks should exhibit. Results of an experiment carried out with cold {sup 87}Rb atoms in a magneto-optical trap agree with the theoretical prediction.

Yang, G. Q.; Xu, P. [State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Wuhan 430071 (China); Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071 (China); Graduate University, Chinese Academy of Sciences, Beijing 100049 (China); Wang, J.; Zhan, M. S. [State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Wuhan 430071 (China); Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071 (China); Zhu Yifu [Department of Physics, Florida International University, Miami, Florida 33199 (United States)

2010-10-15

34

Modulated low-level electromagnetic field effects on EEG visual event-related potentials  

Microsoft Academic Search

The aim of this study was experimental investigation of the effects of low-level modulated microwaves on the human central nervous system function using electroencephalo- graphic (EEG) visual event-related potentials. Thirty healthy volunteers were exposed and sham- exposed to the electromagnetic field (EMF) (450 MHz, 0.16 mW\\/cm2) modulated at 21 Hz frequency during visual oddball tasks. During the task the participants

Jaanus Lass; Kristjan Kruusing; Hiie Hinrikus

2008-01-01

35

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. PMID:21829195

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

36

Evaluation of RF electromagnetic field exposure levels from cellular base stations in Korea.  

PubMed

This article presents the measurement results of human exposure to CDMA800 and CDMA1800 signals at locations in Korea where the general public has expressed concern. Measurements were performed at 50 locations across the country to compare the electromagnetic field levels with the general public exposure compliance limits. At each site, the distances between the nearest single or co-located base station and measurement positions were within a range of approximately 32-422 m. The measured exposure levels were very low compared with the international standard and the Korean human protection notice. The highest field level was 1.5 V/m, which corresponds to 0.15% of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines for human exposure. PMID:20564176

Kim, Byung Chan; Park, Seong-Ook

2010-09-01

37

Gravitational radiation as radiation same level of electromagnetic and its generation in pulsed high-current discharge  

NASA Astrophysics Data System (ADS)

The notion of gravitational radiation as a radiation of the same level as the electromagnetic radiation is based on theoretically proved and experimentally confirmed fact of existence of stationary states of an electron in its gravitational field characterized by the gravitational constant K = 1042G (G is the Newtonian gravitational constant) and unrecoverable space-time curvature A. This paper gives an overview of the authors' works [1, 2, 3, 4], which set out the relevant results. Additionally, data is provided on the broadening of the spectra characteristic radiation. The data show that this broadening can be explained only by the presence of excited states of electrons in their gravitational field. What is more, the interpretation of the new line of X-ray emission spectrum according to the results of observation of MOS-camera of XMM-Newton observatory is of interest. The given work contributes into further elaboration of the findings considering their application to dense high- temperature plasma of multiple-charge ions. This is due to quantitative character of electron gravitational radiation spectrum such that amplification of gravitational radiation may take place only in multiple-charge ion high-temperature plasma.

Fisenko, S. I.; Fisenko, I. S.

2015-01-01

38

New Fe I Level Energies and Line Identifications from Stellar Spectra  

NASA Astrophysics Data System (ADS)

The spectrum of the Fe I atom is critical to many areas of astrophysics and beyond. Measurements of the energies of its high-lying levels remain woefully incomplete, however, despite extensive laboratory and solar analysis. In this work, we use high-resolution archival absorption-line ultraviolet and optical spectra of stars whose warm temperatures favor moderate Fe I excitation. We derive the energy for a particular upper level in Kurucz's semiempirical calculations by adopting a trial value that yields the same wavelength for a given line predicted to be about as strong as that of a strong unidentified spectral line observed in the stellar spectra, then checking the new wavelengths of other strong predicted transitions that share the same upper level for coincidence with other strong observed unidentified lines. To date, this analysis has provided the upper energies of 66 Fe I levels. Many new energy levels are higher than those accessible to laboratory experiments; several exceed the Fe I ionization energy. These levels provide new identifications for over 2000 potentially detectable lines. Almost all of the new levels of odd parity include UV lines that were detected but unclassified in laboratory Fe I absorption spectra, providing an external check on the energy values. We motivate and present the procedure, provide the resulting new energy levels and their uncertainties, list all the potentially detectable UV and optical new Fe I line identifications and their gf values, point out new lines of astrophysical interest, and discuss the prospects for additional Fe I energy level determinations.

Peterson, Ruth C.; Kurucz, Robert L.

2015-01-01

39

Electromagnetic Radiography (EMR) for the detection of low-level chemical contamination in the ground  

NASA Astrophysics Data System (ADS)

Electromagnetic Radiography (EMR)TM provides direct, high- resolution images of low-level chemical contamination in the ground at concentration levels in the parts-per-billion range ((mu) g/kg). This new sensor system can distinguish between dense, non-aqueous phase liquids (DNAPLs) and light, non- aqueous phase liquids (LNAPLs). Ionic chemicals can be distinguished from non-ionic chemicals, and dissolved-phase chemicals in the water table can be distinguished from liquid- phase contaminants in the vadose zone trapped in the pore spaces of the soil. EMRTM is derived from high-performance ground-penetrating radar (GPR). Like its predecessor, EMRTM provides direct images of subsurface geologic structures, including faults, fracture zones, bedrock profiles, bedding planes, clay lenses and infiltration zones. The system employs electromagnetic impulses in the radio- frequency range of 30 MHz to 480 MHz. Specific chemicals have been found to produce unique responses in this frequency domain, leading to the discovery that discrete energy bands are being excited at the molecular level. Much work remains to be done on the characterization of specific chemicals in the radio-frequency (RF) domain. Meanwhile, conventional soil testing can be used to identify the chemicals and 'calibrate' the EMRTM field data. It is now possible to use non- intrusive remote sensing techniques to map the lateral and vertical distribution of specific low-level chemical contaminants on a production basis. The EMRTM system is currently capable of providing 100 percent volumetric inspection of 3 to 5 acres per day to a depth of several meters, including clay.

Finci, Aka G.; Stanfill, Daniel F., III

1999-12-01

40

Phase Control of Electromagnetically Induced Grating in a Doppler-Broadened ?-Type Three-Level System  

NASA Astrophysics Data System (ADS)

We theoretically investigate the phenomena of electromagnetically induced grating in a doppler-broadened ?-type three-level atomic system with the spontaneously generated coherence (SGC) effect enhanced by an incoherence pump. It is found that the model can effectively diffract a weak probe field into high-order direction. We attribute the enhancement of diffraction mainly to the quantum interference resulting from the cross coupling between the two decay pathways. The diffraction efficiency behaves phase and doppler broadening-dependent phenomena, and can be greatly modulated by the SGC effect. Compared to the counter-propagating case, the co-propagating setting is more suitable for the purpose considered in this paper due to the effectiveness of Doppler-free.

Qiu, Tian-Hui; Ma, Hong-Yang; Zheng, Chun-Hong; Chen, Li-Bo; Cheng, Qiang

2015-01-01

41

The cyclopropene radical cation: Rovibrational level structure at low energies from high-resolution photoelectron spectra  

NASA Astrophysics Data System (ADS)

The cyclopropene radical cation (c-C3H_4^+) is an important but poorly characterized three-membered-ring hydrocarbon. We report on a measurement of the high-resolution photoelectron and photoionization spectra of cyclopropene and several deuterated isotopomers, from which we have determined the rovibrational energy level structure of the widetildeX^+ 2B2 ground electronic state of c-C3H_4^+ at low energies for the first time. The synthesis of the partially deuterated isotopomers always resulted in mixtures of several isotopomers, differing in their number of D atoms and in the location of these atoms, so that the photoelectron spectra of deuterated samples are superpositions of the spectra of several isotopomers. The rotationally resolved spectra indicate a C2v-symmetric R0 structure for the ground electronic state of c-C3H_4^+. Two vibrational modes of c-C3H_4^+ are found to have vibrational wave numbers below 300 cm-1, which is surprising for such a small cyclic hydrocarbon. The analysis of the isotopic shifts of the vibrational levels enabled the assignment of the lowest-frequency mode (fundamental wave number of ?110 cm-1 in c-C3H_4^+) to the CH2 torsional mode (? _8^+, A2 symmetry) and of the second-lowest-frequency mode (?210 cm-1 in c-C3H_4^+) to a mode combining a CH out-of-plane with a CH2 rocking motion (? _{15}^+, B2 symmetry). The potential energy along the CH2 torsional coordinate is flat near the equilibrium structure and leads to a pronounced anharmonicity.

Vasilatou, K.; Michaud, J. M.; Baykusheva, D.; Grassi, G.; Merkt, F.

2014-08-01

42

Measurement of radiated electromagnetic field levels before and after a changeover to energy-efficient lighting.  

PubMed

An energy-efficient lighting retrofit at the Food and Drug Administration (FDA) Winchester Engineering and Analytical Center (WEAC) presented the opportunity to measure the electromagnetic (EM) environments in several rooms before and after changing the fluorescent lighting systems and to compare the changes in EM fields with the proposed standard EM immunity levels. Three rooms, representing the types of work areas in the laboratory, were selected and measured before and after the lighting changeover. Electric and magnetic field measurements were taken in the extremely low frequency (ELF), very low frequency (VLF), and radio frequency (RF) ranges of the EM spectrum. In 2 rooms, ELF electric fields were reduced and VLF and RF electric fields were increased as a result of the changeover to high-frequency fixtures. A third room received low-frequency, energy-efficient fixtures during this changeover, and this change resulted in only a slight increase of the ELF electric fields. The ELF magnetic fields were greatly reduced in 2 but only slightly reduced in the third room. No significant change was seen in VLF or RF magnetic fields for any of these rooms. Some field-strength measurements exceeded the proposed immunity levels recommended in the draft International Electrotechnical Commission standard IEC 60601-1-2 (rev. 2). The data show that increasing the separation distance from the fluorescent light fixtures greatly reduces the field-strength levels, limiting the potential for EM interference. PMID:11383307

Kerr, L N; Boivin, W S; Boyd, S M; Coletta, J N

2001-01-01

43

Effects of electromagnetic fields on photophasic circulating melatonin levels in American kestrels.  

PubMed

Birds reproduce within electromagnetic fields (EMFs) from transmission lines. Melatonin influences physiologic and behavioral processes that are critical to survival, and melatonin has been equivocally suppressed by EMFs in mammalian species. We examined whether EMFs affect photophasic plasma melatonin in reproducing adult and fledgling American kestrels (Falco sparverius), and whether melatonin was correlated with body mass to explain previously reported results. Captive kestrel pairs were bred under control or EMF conditions for one (short-term) or two (long-term) breeding seasons. EMF exposure had an overall effect on plasma melatonin in male kestrels, with plasma levels suppressed at 42 days and elevated at 70 days of EMF exposure. The similarity in melatonin levels between EMF males at 42 days and controls at 70 days suggests a seasonal phase-shift of the melatonin profile caused by EMF exposure. Melatonin was also suppressed in long-term fledglings, but not in short-term fledglings or adult females. Melatonin levels in adult males were higher than in adult females, possibly explaining the sexually dimorphic response to EMFs. Melatonin and body mass were not associated in American kestrels. It is likely that the results are relevant to wild raptors nesting within EMFs. PMID:10544158

Fernie, K J; Bird, D M; Petitclerc, D

1999-11-01

44

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

45

Proton Spectra 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 38 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 spectra to satellite measurements at ˜300-700 MeV available from IMP8, SAMPEX, and/or GOES for 26 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, 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. In a companion paper (Atwell et al., Session F25), we also discuss the implications of these spectral 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, Allan J.

46

Status of the Level 0 Trigger Processor of the NA62 Liquid Krypton Electromagnetic Calorimeter  

NASA Astrophysics Data System (ADS)

The NA62 experiment at the CERN SPS aims to measure the Branching Ratio of the ultra-rare decay K^+ rightarrow ?^+?bar?, collecting about 100 events in two years of data taking with a signal to background ratio of 10:1. A hermetic photon veto system has been designed to efficiently reject the ?0 background, one of the main background sources, and the 20-ton liquid krypton calorimeter is a fundamental component of such system in the angular acceptance region 1-10 mrad. In this paper, we present the design of the Level 0 trigger processor that is able to identify electromagnetic clusters in the calorimeter providing information on time, position and energy reconstruction for each cluster. In particular, it is composed of 36 readout boards (TEL62), organized in a three layer parallel system, 108 mezzanines and 215 high-performance FPGAs. The system has been designed to sustain an instantaneous hit rate of 40 MHz, to process data with a latency of about 100 ?s, and to achieve a time resolution of 1.5 ns on the single cluster. Performance and functionality test results of a trigger slice, together with an updated status report of the whole level 0 trigger project, will be presented.

Bonaiuto, V.; de Simone, N.; Federici, L.; Sargeni, F.; Badoni, D.; Fucci, A.; Paoluzzi, G.; Salamon, A.; Salina, G.; Santovetti, E.; Checcucci, B.; Papi, A.; Piccini, M.; Bizzarri, M.; Venditti, S.

2014-06-01

47

Examination of level density prescriptions for the interpretation of high-energy ? -ray spectra  

NASA Astrophysics Data System (ADS)

High-energy ? -ray spectra measured by our group involving the compound nuclei (CN) 63Cu at excitation energy E*˜36 MeV with average angular momentum J =12 -17 ? , 97Tc at E*˜29 -50 MeV with J =12 -14 ? , 113Sb at E*=109 and 121 MeV with J =49 -59 ? , and 201Tl at E*=39.5 and 47.5 MeV with J =18 -24 ? have been analyzed utilizing the level density prescriptions of (i) Ignatyuk, Smirenkin, and Tishin (IST), (ii) Budtz-Jorgensen and Knitter (BJK), and (iii) Kataria, Ramamurthy, and Kapoor (KRK). These three prescriptions have been tested for the correct statistical model description of high-energy ? rays in the light of extracting the giant dipole resonance (GDR) parameters at low excitation energy and spin where shell effects might play an important role, as well as at high excitation energy where shell effects have melted. Interestingly, only the IST level density prescription could explain the high-energy ? -ray spectra with reasonable GDR parameters for all four nuclei.

Bhattacharya, Srijit; Pandit, Deepak; Dey, Balaram; Mondal, Debasish; Mukhopadhyay, S.; Pal, Surajit; De, A.; Banerjee, S. R.

2014-11-01

48

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

49

Occupational exposure of dentists to electromagnetic fields produced by magnetostrictive cavitrons alters the serum cortisol level  

PubMed Central

Objectives: Some studies indicate that dentistry is one of the job categories with high potential exposure to elevated levels of extremely low frequency magnetic fields. In spite of this, information on occupational exposure of dentists to these fields is scarce. Studies on other common sources of electromagnetic fields (EMFs) such as mobile base stations have shown alterations in the cortisol level following exposure of humans to these sources. The aim of this study is to compare the level of cortisol among dentists and dentistry students who are being occupationally exposed to EMFs emitted by magnetostrictive cavitrons (case group) and among their counterparts who are not being exposed to these fields (control group). Materials and Methods: In this case–control study, blood samples were collected from 41 dentists and dentistry students, 21 of whom were exposed to EMFs emitted by cavitrons as the case group and 20 who were not exposed as the control group, twice; i.e. before work (at 8:30–9:30 a.m.) and after work (11:30–12:30 a.m.). The samples were coded and the serum cortisol level was investigated using the ELISA method (Cortisol AccuBind ELISA Kits). Results: The serum cortisol level of dentists and dental students in the morning (before starting the work) in the control group was 189.15 ± 110.70 (mean ± SD) whereas it was 157.77 ± 112.03 in those who were occupationally exposed to EMFs produced by the use of cavitrons. This difference was not statistically significant (P = 0.373). In contrast, the serum cortisol level of the participants in the noon (after stopping the work) in the control group was 136.25 ± 67.91 (mean ± SD) while it was 88.58 ± 52.83 in those who were occupationally exposed to EMFs produced by the use of cavitrons. This time, the observed difference was statistically significant (P = 0.016). In this light, while the difference between serum cortisol levels of dentists and dental students in the morning and after stopping the work was not statistically significant (P = 0.06), in the EMF-exposed group the cortisol level decreased significantly from 157.77 ± 112.03 in the morning to 88.58 ± 52.83 in the noon (P = 0.001). Conclusions: As far as we know, this is the first study that evaluated the effect of occupational exposure of dentists to EMFs on their serum cortisol level. The EMFs produced by magnetostrictive cavitrons can decrease the serum cortisol level in dentists. As cortisol plays an important role in blood pressure regulation, cardiovascular, and immune system function, a low cortisol level may threaten health. More studies are needed to clearly understand the effects of EMFs emitted by magnetostrictive cavitron on the level of stress hormones. As some studies have shown that exposure to EMFs has no effect on the cortisol level, whereas other studies reported either an increase or a decrease in the cortisol level, it can be concluded that the effects of exposure to EMFs may occur only at specific absorbed energies or energy absorption rates (usually known as window) similar to that exists in the case of exposure to the low doses of ionizing radiations. PMID:22690053

Mortazavi, S. M. J.; Vazife-Doost, S.; Yaghooti, M.; Mehdizadeh, S.; Rajaie-Far, A.

2012-01-01

50

Application of Manning's Formula for Estimation of Liquid Metal Levels in Electromagnetic Flow Measurements  

NASA Astrophysics Data System (ADS)

Lorentz force velocimetry is a new technique in electromagnetic flow measurements based on exposing an electrical conducting metal to a static magnetic field and measuring the force acting on the magnet system. The calibration procedure of a Lorentz force flowmeter used in industrial open-channel flow measurements is difficult because of the fluctuating liquid level in the channel. In this paper, the application of Manning's formula to estimate the depth of a liquid metal flowing in an open channel is analyzed by using the numerical modeling. Estimations of Manning's n parameter for aluminum show higher values as compared with water flowing in artificial channels. Saint-Venant equations are solved in order to analyze the wave propagation at the free surface of the liquid. Numerical results show a significant damping of waves at the surface of liquid metals as compared with water. Therefore, the Manning formula can be used to correlate the liquid depth and the flow rate in LFF numerical calibration procedure. These results show that the classical formulas, used exclusively to study the water flow in open channels, can be also applied for the liquid metals. The application of Manning's formulas requires experimental measurements of the parameter n, which depends on the channel bed roughness and also on the physical properties of the liquid flowing in channel.

Stelian, Carmen

2015-02-01

51

Electromagnetic Signals from Bacterial DNA  

E-print Network

Chemical reactions can be induced at a distance due to the propagation of electromagnetic signals during intermediate chemical stages. Although is is well known at optical frequencies, e.g. photosynthetic reactions, electromagnetic signals hold true for muck lower frequencies. In E. coli bacteria such electromagnetic signals can be generated by electric transitions between energy levels describing electrons moving around DNA loops. The electromagnetic signals between different bacteria within a community is a "wireless" version of intercellular communication found in bacterial communities connected by "nanowires". The wireless broadcasts can in principle be of both the AM and FM variety due to the magnetic flux periodicity in electron energy spectra in bacterial DNA orbital motions.

A. Widom; J. Swain; Y. N. Srivastava; S. Sivasubramanian

2012-02-09

52

Chronic Electromagnetic Exposure at Occupational Safety Level Does Not Affect the Metabolic Profile nor Cornea Healing after LASIK Surgery.  

PubMed

LASIK eye surgery has become a very common practice for myopic people, especially those in the military. Sometimes undertaken by people who need to keep a specific medical aptitude, this surgery could be performed in secret from the hierarchy and from the institute medical staff. However, even though the eyes have been previously described as one of the most sensitive organs to electromagnetic fields in the human body, no data exist on the potential deleterious effects of electromagnetic fields on the healing eye. The consequences of chronic long-lasting radar exposures at power density, in accordance with the occupational safety standards (9.71?GHz, 50?W/m(2)), were investigated on cornea healing. The metabolic and clinical statuses after experimental LASIK keratotomy were assessed on the different eye segments in a New Zealand rabbit model. The analysis methods were performed after 5 months of exposure (1?hour/day, 3 times/week). Neither clinical or histological examinations, nor experimental data, such as light scattering, (1)H-NMR HRMAS metabolomics, (13)C-NMR spectra of lipidic extracts, and antioxidant status, evidenced significant modifications. It was concluded that withdrawing the medical aptitude of people working in electromagnetic field environments (i.e., radar operators in the navy) after eye surgery was not justified. PMID:24757560

Crouzier, David; Dabouis, Vincent; Gentilhomme, Edgar; Vignal, Rodolphe; Bourbon, Fréderic; Fauvelle, Florence; Debouzy, Jean-Claude

2014-01-01

53

Optical absorption spectra and energy levels of Er3+ ions in glassy lithium tetraborate matrix  

NASA Astrophysics Data System (ADS)

The optical absorption spectra of Er:Li2B4O7 glasses are studied in the range 200-800 nm. The lines corresponding to the direct f-f parity-forbidden intraconfigurational transitions from the ground 4 I 15/2 state to the levels of the excited 4 F 9/2, 4 S 3/2, 2 H 9/2, 2 H 11/2, 4 F 7/2, 4 F 5/2, 4 F 3/2, 2 H 9/2, 4 G 11/2, 4 D 3/2, 4 D 1/2, and 2 D 3/2 states are found.

Danilyuk, P. S.; Popovich, K. P.; Puga, P. P.; Gomonai, A. I.; Primak, N. V.; Krasilinets, V. N.; Turok, I. I.; Puga, G. D.; Rizak, V. M.

2014-11-01

54

Study the effect of gray component replacement level on reflectance spectra and color reproduction accuracy  

NASA Astrophysics Data System (ADS)

The aim of this study is investigation of gray component replacement (GCR) levels on reflectance spectrum for different overprints of the inks and color reproduction accuracy. The most commonly implemented method in practice for generation of achromatic composition is gray component replacement (GCR). The experiments in this study, have been performed in real production conditions with special test form generated by specialized software. The measuring of reflection spectrum of printed colors, gives a complete conception for the effect of different gray component replacement levels on color reproduction accuracy. For better data analyses and modeling of processes, we have calculated (converted) the CIEL*a*b* color coordinates from the reflection spectra data. The assessment of color accuracy by using different GCR amount has been made by calculation of color difference ?E* ab. In addition for the specific printing conditions we have created ICC profiles with different GCR amounts. A comparison of the color gamuts has been performed. For a first time a methodology is implemented for examination and estimation of effect of GCR levels on color reproduction accuracy by studying a big number of colors in entire visible spectrum. Implementation in practice of the results achieved in this experiment, will lead to improved gray balance and better color accuracy. Another important effect of this research is reduction of financial costs of printing production by decreasing of ink consumption, indirect reduction of emissions during the manufacture of inks and facilitates the process of deinking during the recycling paper.

Spiridonov, I.; Shopova, M.; Boeva, R.

2013-03-01

55

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

56

[The role of transcription factors in the response of mouse lymphocytes to low-level electromagnetic and laser radiations].  

PubMed

The effects of low-intensity laser radiation (LILR, 632.8 nm, 0.2 mW/cm2) and low-intensity electromagnetic waves (LIEW, 8.15 - 18 GHz, 1 MW/cm2) on the production of transcription factors in lymphocytes from NMRI male mice were examined. The total level of NF-KB and its phosphorylated metabolite Phospho-NF-kappaB, as well as the regulatory protein IkappaB-alpha were determined in spleen lymphocytes subjected to laser or microwave radiations. The proteins were determined by immunoblotting. Laser light induced a lowering in the level of NF-kappaB and IkappaB-alpha. By contrast, irradiation with electromagnetic waves resulted in a significant increase in the amount of NF-kappaB and IkappaB-alpha. The phosphorylated form of NF-kappaB did not noticeably change under either of the two kinds of radiation. The results showed that electromagnetic waves activate the production of both NF-kappaB and the regulatory protein IkappaB-alpha and these data confirm the stress character of the response of spleen lymphocytes to low-level microwaves of the centimeter range. PMID:17969924

Khrenov, M O; Cherenkov, D A; Glushkova, O V; Novoselova, T V; Lunin, S M; Parfeniuk, S B; Lysenko, E A; Novoselova, E G; Fesenko, E E

2007-01-01

57

Pineal melatonin level disruption in humans due to electromagnetic fields and ICNIRP limits.  

PubMed

The International Agency for Research on Cancer (IARC) classifies electromagnetic fields (EMFs) as 'possibly carcinogenic' to humans that might transform normal cells into cancer cells. Owing to high utilisation of electricity in day-to-day life, exposure to power-frequency (50 or 60 Hz) EMFs is unavoidable. Melatonin is a natural hormone produced by pineal gland activity in the brain that regulates the body's sleep-wake cycle. How man-made EMFs may influence the pineal gland is still unsolved. The pineal gland is likely to sense EMFs as light but, as a consequence, may decrease the melatonin production. In this study, more than one hundred experimental data of human and animal studies of changes in melatonin levels due to power-frequency electric and magnetic fields exposure were analysed. Then, the results of this study were compared with the International Committee of Non-Ionizing Radiation Protection (ICNIRP) limit and also with the existing experimental results in the literature for the biological effect of magnetic fields, in order to quantify the effects. The results show that this comparison does not seem to be consistent despite the fact that it offers an advantage of drawing attention to the importance of the exposure limits to weak EMFs. In addition to those inconsistent results, the following were also observedfrom this work: (i) the ICNIRP recommendations are meant for the well-known acute effects, because effects of the exposure duration cannot be considered and (ii) the significance of not replicating the existing experimental studies is another limitation in the power-frequency EMFs. Regardless of these issues, the above observation agrees with our earlier study in which it was confirmed that it is not a reliable method to characterise biological effects by observing only the ratio of AC magnetic field strength to frequency. This is because exposure duration does not include the ICNIRP limit. Furthermore, the results show the significance of disruption of melatonin due to exposure to weak EMFs, which may possibly lead to long-term health effects in humans. PMID:23051584

Halgamuge, Malka N

2013-05-01

58

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

59

Soft X-ray coronal spectra at low activity levels observed by RESIK  

E-print Network

The quiet-Sun X-ray emission is important for deducing coronal heating mechanisms, but it has not been studied in detail since the Orbiting Solar Observatory (OSO) spacecraft era. Bragg crystal spectrometer X-ray observations have generally concentrated on flares and active regions. The high sensitivity of the RESIK (REntgenovsky Spectrometer s Izognutymi Kristalami) instrument on the CORONAS-F solar mission has enabled the X-ray emission from the quiet corona to be studied in a systematic way for the first time. Our aim is to deduce the physical conditions of the non-flaring corona from RESIK line intensities in several spectral ranges using both isothermal and multithermal assumptions. We selected and analyzed spectra in 312 quiet-Sun intervals in January and February 2003, sorting them into 5 groups according to activity level. For each group, the fluxes in selected spectral bands have been used to calculate values parameters for the best-fit that lead to a intensities characteristic of each group. We used...

Sylwester, B; Phillips, K J H

2010-01-01

60

The far-infrared and microwave spectra of the CH radical in the v = 1 level of the X2  

E-print Network

spectroscopy; Laser magnetic resonance; Far-infrared laser frequencies; CH radical; Lambda-type doubling.sciencedirect.com Journal of Molecular Spectroscopy 247 (2008) 128­139 #12;by far-infrared laser magnetic resonance (LMRThe far-infrared and microwave spectra of the CH radical in the v = 1 level of the X2 P state

61

Comment on: "Electromagnetically induced left-handedness in optically excited four-level atomic media"  

E-print Network

We discuss the recent proposal by Thommen and Mandel (Phys. Rev. Lett. {\\bf 96}, 053601 (2006)) for electromagnetically induced negative refraction. Although the main conclusion of the paper -- the possibility to achieve negative refraction in an experimentally accessible atomic scheme -- remains valid, we show that the weak-excitation approximation used is invalid in the parameter regime studied and leads to quantitatively incorrect predictions. We show that negative refraction is always accompanied by absorption rather than by gain, and that the maximum value of the refraction-absorption ratio is of order unity.

Jürgen Kästel; Michael Fleischhauer

2006-07-21

62

Effect of rosmarinic acid on sertoli cells apoptosis and serum antioxidant levels in rats after exposure to electromagnetic fields.  

PubMed

Rosmarinic acid belongs to the group of polyphenols; it has antioxidant, anti-inflammatory and antimicrobial activities and help to prevent cell damage caused by free radicals. The objective was to study the effect of Rosmarinic acid on sertolli cells apoptosis and serum antioxidant levels in rats after they were exposed to electromagnetic fields. Male Wistar rats (n=40) were allocated into three groups: control group (n=10) that received 5 cc normal saline (0.9% NaCl) daily by gavage method, Rosmarinic acid group that received 5mg/rat (gavage) (n=10), electromagnetic fields (EMF) group that had exposure with 50 hz (n=20) which was subdivided to two groups of 10; EMF group and treatment group. Treatment group received 5mg/rat (gavage) Rosmarinic acid daily for 6 weeks, respectively. However, the control group just received an equal volume of distilled water daily (gavage). On the 42nd day of research, 5 cc blood was collected to measure testosterone hormones, total antioxidant capacity (TAC), levels from whole group's analysis. Level of malondialdehyde (MDA) levels and sertoli cells apoptosis significantly decreased in the group that received 5mg/rat of Rosmarinic acid (P<0.05) in comparison with experimental groups. Level of testosterone, total antioxidant capacity (TAC), significantly increased in groups that received Rosmarinic acid (P<0.05). Since in our study 5mg/rat of Rosmarinic acid showed significantly preventive effect on cell damages especial sertoli cells apoptosis that caused with EMF, it seems that using Rosmarinic acid as food additive can be effective for supporting people living under EMF environmental pollution. PMID:24311872

Hajhosseini, Laleh; Khaki, Arash; Merat, Ehsan; Ainehchi, Nava

2013-01-01

63

Accurate vibrational spectra via molecular tailoring approach: A case study of water clusters at MP2 level  

NASA Astrophysics Data System (ADS)

In spite of the recent advents in parallel algorithms and computer hardware, high-level calculation of vibrational spectra of large molecules is still an uphill task. To overcome this, significant effort has been devoted to the development of new algorithms based on fragmentation methods. The present work provides the details of an efficient and accurate procedure for computing the vibrational spectra of large clusters employing molecular tailoring approach (MTA). The errors in the Hessian matrix elements and dipole derivatives arising due to the approximation nature of MTA are reduced by grafting the corrections from a smaller basis set. The algorithm has been tested out for obtaining vibrational spectra of neutral and charged water clusters at Møller-Plesset second order level of theory, and benchmarking them against the respective full calculation (FC) and/or experimental results. For (H2O)16 clusters, the estimated vibrational frequencies are found to differ by a maximum of 2 cm-1 with reference to the corresponding FC values. Unlike the FC, the MTA-based calculations including grafting procedure can be performed on a limited hardware, yet take a fraction of the FC time. The present methodology, thus, opens a possibility of the accurate estimation of the vibrational spectra of large molecular systems, which is otherwise impossible or formidable.

Sahu, Nityananda; Gadre, Shridhar R.

2015-01-01

64

Accurate vibrational spectra via molecular tailoring approach: A case study of water clusters at MP2 level.  

PubMed

In spite of the recent advents in parallel algorithms and computer hardware, high-level calculation of vibrational spectra of large molecules is still an uphill task. To overcome this, significant effort has been devoted to the development of new algorithms based on fragmentation methods. The present work provides the details of an efficient and accurate procedure for computing the vibrational spectra of large clusters employing molecular tailoring approach (MTA). The errors in the Hessian matrix elements and dipole derivatives arising due to the approximation nature of MTA are reduced by grafting the corrections from a smaller basis set. The algorithm has been tested out for obtaining vibrational spectra of neutral and charged water clusters at Møller-Plesset second order level of theory, and benchmarking them against the respective full calculation (FC) and/or experimental results. For (H2O)16 clusters, the estimated vibrational frequencies are found to differ by a maximum of 2 cm(-1) with reference to the corresponding FC values. Unlike the FC, the MTA-based calculations including grafting procedure can be performed on a limited hardware, yet take a fraction of the FC time. The present methodology, thus, opens a possibility of the accurate estimation of the vibrational spectra of large molecular systems, which is otherwise impossible or formidable. PMID:25573553

Sahu, Nityananda; Gadre, Shridhar R

2015-01-01

65

A laboratory investigation of electromagnetic bias in sea level measurements by microwave altimeters  

NASA Technical Reports Server (NTRS)

To contribute to a better understanding of the electromagnetic bias in radar altimetry, a series of experiments was conducted using a focused beam radar set at 13.5-GHz frequency. For pure wind wave fields, the authors found the bias to be a quadratic function of each of the commonly used parameters, namely, the significant wave height, the wind speed, the water elevation skewness, and significant slope. The bias divided by the significant wave height is a linear function of these parameters. The coefficients in bias representation as a function of either the significant wave height or the wind speed are significantly different from values obtained in field experiments. This led to the conclusion that none of the latter parameters can be taken solely to account for all observed bias variations. Instead, dimensionless parameters such as the wave skewness or a dimensionless wave height are shown to be more appropriate.

Branger, H.; Bliven, L.; Ramamonjiarisoa, A.

1991-01-01

66

Meson exchange effects in elastic ep scattering at loop level and the electromagnetic form factors of the proton  

NASA Astrophysics Data System (ADS)

A new form of two-photon exchange (TPE) effect is studied to explain the discrepancy between unpolarized and polarized experimental data in elastic ep scattering. The mechanism is based on a simple idea that apart from the usual TPE effects from box and crossed-box diagrams, the mesons may also be exchanged in elastic ep scattering by two-photon coupling at loop level. The detailed study shows such contributions to reduced unpolarized cross section (?un) and polarized observables (Pt,Pl) at fixed Q2 are only dependent on proton's electromagnetic form factors GE ,M and a new unknown universal parameter g. After combining this contribution with the usual TPE contributions from box and crossed-box diagrams, the ratio ?pGE/GM extracted from the recent precise unpolarized and polarized experimental data can be described consistently.

Chen, Hong-Yu; Zhou, Hai-Qing

2014-10-01

67

ORIGEN-S (. cap alpha. ,n) neutron source spectra in borosilicate glass containing HLW (high-level waste)  

SciTech Connect

There is growing interest in the methodology and computational software for evaluating the (..cap alpha..,n) source spectra produced in mixtures of high-level waste (HLW) and borosilicate glass. The need for this development has been seen in previous work involving the analysis of HLW in borosilicate glass. Descriptions and applications of the ORIGEN-S method of computing neutron source spectra by both (..cap alpha..,n) reactions and spontaneous fission of UO/sub 2/ spent fuel have been reported previously. This summary presents a significant expansion of the ORIGEN-S (..cap alpha..,n) model to include ..cap alpha..-interactions with the light elements of borosilicate glass.

Hermann, O.W.; Parks, C.V.; Ludwig, S.B.

1987-01-01

68

Piecewise constant level set algorithm for an inverse elliptic problem in nonlinear electromagnetism  

E-print Network

An inverse problem of identifying inhomogeneity or crack in the workpiece made of nonlinear magnetic material is investigated. To recover the shape from the local measurements, a piecewise constant level set algorithm is proposed. By means of the Lagrangian multiplier method, we derive the first variation w.r.t the level set function and obtain the descent direction by the adjoint variable method. Numerical results show the robustness and effectiveness of our algorithm applied to reconstruct some complex shapes.

Xiangyin Kong; Zhengfang Zhang; Zhengda Huang

2012-12-03

69

Energy spectra and level statistics of Fibonacci and Thue-Morse chains  

NASA Astrophysics Data System (ADS)

We study the density of states, the distribution of energy spacings, and the transmission coefficient of one-dimensional quasiperiodic Fibonacci and Thue-Morse systems. We consider arrays of ? potentials with constant separation and two potential strengths, and tight-binding systems with constant nearest-neighbor couplings and two different on-site energies. The quasiperiodicity lies in the arrangement of the two possible values of either the potential strengths or the on-site energies. We analyze the fractal character of the energy spectra of these systems through their integrated density of states and fractal dimensionality. We study the average with respect to energy of the transmission coefficient, which turns out to be a good way to measure the regularity of the system.

Carpena, P.; Gasparian, V.; Ortuño, M.

1995-05-01

70

Theory of core-level spectra in x-ray photoemission of pristine and doped graphene  

NASA Astrophysics Data System (ADS)

Spectra of the C1s core hole, created in x-ray photoemission and screened by electronic excitations in pristine and doped graphene are calculated and discussed. We find that singular effects in the lineshapes are not possible in the pristine graphene, and their observation should be connected with the doping. However, the structure of the low-energy excitation spectrum in the region where the singular behavior is expected leads to asymmetries in the core-hole lineshapes in pristine graphene similar to those in doped graphene. This makes the analysis more complex than in the case of metals and may lead to an incorrect or incomplete interpretation of the experimental results.

Despoja, V.; Šunji?, M.

2013-12-01

71

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

2011-08-01

72

Effects on chickens of continuous exposure to low level electromagnetic, electric, and magnetic fields  

E-print Network

. These effects have been observed at power levels as low as 5 to 10 mW/cm at frequencies in the 3000 MHz region. 2 (8) The Soviet bloc countries have reported a great number of microwave effects on personnel working with microwave equipment. Most... was to confirm the effect on the growth rate of chickens during and after exposure to "low level" microwave radiation and VLF (Very Low Frequency) electric and magnetic fields. The second objective was to deter- mine whether the effects of ionizing radiation...

Howell, Robert Sherwood

1972-01-01

73

Variability in electromagnetic field levels over time, and Monte-Carlo simulation of exposure parameters.  

PubMed

This article analyses the electric field levels around medium-wave transmitters, delimiting the temporal variability of the levels received at a pre-established reception point. One extensively used dosimetric criterion is to consider historical levels of the field recorded over a certain period of time so as to provide an overall perspective of radio-frequency electric field exposure in a particular environment. This aspect is the focus of the present study, in which the measurements will be synthesised in the form of exposure coefficients. Two measurement campaigns were conducted: one short term (10 days) and the other long term (1 y). The short-term data were used to study which probability density functions best approximate the measured levels. The long-term data were used to compute the principal statistics that characterise the field values over a year. The data that form the focus of the study are the peak traces, since these are the most representative from the standpoint of exposure. The deviations found were around 6 % for short periods and 12 % for long periods. The information from the two campaigns was used to develop and implement a computer application based on the Monte Carlo method to simulate values of the field, allowing one to carry out robust statistics. PMID:24594905

Pachón-García, F T; Paniagua-Sánchez, J M; Rufo-Pérez, M; Jiménez-Barco, A

2014-12-01

74

Quantal molecular description and universal aspects of the spectra of bosons and fermions in the lowest Landau level  

SciTech Connect

Through the introduction of a class of trial wave functions portraying combined rotations and vibrations of molecules formed through particle localization in concentric polygonal rings, a correlated basis is constructed that spans the translationally invariant part of the lowest-Landau-level (LLL) spectra. These trial functions, referred to as rovibrational molecular (RVM) functions, generalize our previous work that focused exclusively on electronic cusp states, describing them as pure vibrationless rotations. From a computational viewpoint, the RVM correlated basis enables controlled and systematic improvements of the original strongly correlated variational wave function. Conceptually, it provides the basis for the development of a quantal molecular description for the full LLL spectra. This quantal molecular description is universal, being valid for both bosons and fermions, for both the yrast and excited states of the LLL spectra, and for both low and high angular momenta. Furthermore, it follows that all other translationally invariant trial functions (e.g., the Jastrow-Laughlin, compact composite-fermion, or Moore-Read functions) are reducible to a description in terms of an excited rotating and vibrating quantal molecule.

Yannouleas, Constantine; Landman, Uzi [School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430 (United States)

2010-02-15

75

Effect of Extremely Low Frequency Electromagnetic Field and GABAA Receptors on Serum Testosterone Level of Male Rats  

PubMed Central

Background: GABA can influence the steroidogenesis in peripheral and central nervoussystems. Objectives: The present study investigates the interactive effect of GABAA receptors and extremely low frequency electromagnetic field on serum testosterone level of male rats. Patients and Methods: Fifty adult male rats were randomly assigned into 10 groups. Groups 2, 4, 6, 8, and 10 were exposed to ELF-EMF for 30 days 8hrs per day; while, the remaining groups (1, 3, 5, 7, and 9) were sham exposed animals. At the end of the experiment, animals in groups 1 and 2 received normal saline; while, animals in groups 3 and 4 were treated with 1 mg/kg of bicuculline methiodide, and for animals of groups 5 and 6,3 mg/kg of bicuculline was injected. Animals of groups 7 and 8 were treated with 0.5 mg/kg of muscimol hydrobromide and rats in groups 9 and 10 received 2 mg/kg muscimol hydrobromide. About forty minutes after the injection, blood samples were collected and serum testosterone level was assayed using RIA. Results: Administration of muscimol hydrobromide at both doses to sham exposed rats significantly decreased serum testosterone level as compared to sham exposed animals which received saline. Administration of bicuculline methiodide without exposure to ELF-EMF, had no significant effect on testosterone level as compared to group 1. Serum testosterone levels of rats in different groups, exposed to ELF-EMF were statistically the same. Moreover, serum testosterone of exposed and sham exposed rats in each treatment showed no significant difference. Conclusions: No interactivity is present in modulatory effects of GABAA receptors and ELF-EMFs on serum testosterone of male rats. PMID:24719627

Taherianfard, Mahnaz; Bahaddini, Aminolah; Keshtkar, Sara; Fazeli, Mehdi; Shomali, Tahora

2013-01-01

76

Nuclear magnetic resonance inverse spectra of InGaAs quantum dots: Atomistic level structural information  

NASA Astrophysics Data System (ADS)

A wealth of atomistic information is contained within a self-assembled quantum dot (QD), associated with its chemical composition and the growth history. In the presence of quadrupolar nuclei, as in InGaAs QDs, much of this is inherited to nuclear spins via the coupling between the strain within the polar lattice and the electric quadrupole moments of the nuclei. Here, we present a computational study of the recently introduced inverse spectra nuclear magnetic resonance technique to assess its suitability for extracting such structural information. We observe marked spectral differences between the compound InAs and alloy InGaAs QDs. These are linked to the local biaxial and shear strains, and the local bonding configurations. The cation alloying plays a crucial role especially for the arsenic nuclei. The isotopic line profiles also largely differ among nuclear species: While the central transition of the gallium isotopes have a narrow linewidth, those of arsenic and indium are much broader and oppositely skewed with respect to each other. The statistical distributions of electric field gradient (EFG) parameters of the nuclei within the QD are analyzed. The consequences of various EFG axial orientation characteristics are discussed. Finally, the possibility of suppressing the first-order quadrupolar shifts is demonstrated by simply tilting the sample with respect to the static magnetic field.

Bulutay, Ceyhun; Chekhovich, E. A.; Tartakovskii, A. I.

2014-11-01

77

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

78

Leaf Level Chlorophyll Fluorescence Emission Spectra: Narrow Band versus Full 650-800 nm Retrievals  

NASA Astrophysics Data System (ADS)

Recently, chlorophyll fluorescence (ChlF) retrievals in narrow spectral regions (< 1 nm, between 750-770 nm) of the near infrared (NIR) region of Earth's reflected radiation have been achieved from satellites, including the Japanese GOSAT and the European Space Agency's Sciamachy/Envisat. However, these retrievals sample the total full-spectrum ChlF and are made at non-optimal wavelengths since they are not located at the peak fluorescence emission features. We wish to estimate the total full-spectrum ChlF based on emissions obtained at selected wavelengths. For this, we drew upon leaf emission spectra measured on corn leaves obtained from a USDA experimental cornfield in MD (USA). These emission spectra were determined for the adaxial and abaxial (i.e., top and underside) surfaces of leaves measured throughout the 2008 and 2011 growing seasons (n>400) using a laboratory instrument (Fluorolog-3, Horiba Scientific, USA), recorded in either 1 nm or 5 nm increments with monochromatic excitation wavelengths of either 532 or 420 nm. The total ChlF signal was computed as the area under the continuous spectral emission curves, summing the emission intensities (counts per second) per waveband. The individual narrow (1 or 5 nm) waveband emission intensities were linearly related to full emission values, with variable success across the spectrum. Equations were developed to estimate total ChlF from these individual wavebands. Here, we report the results for the average adaxial/abaxial emissions. Very strong relationships were achieved for the relatively high fluorescence intensities at the red chlorophyll peak, centered at 685 nm (r2= 0.98, RMSE = 5.53 x 107 photons/s) and in the nearby O2-B atmospheric absorption feature centered at 688 nm (r2 = 0.94, RMSE = 4.04 x 107), as well as in the far-red peak centered at 740 nm (r2=0.94, RMSE = 5.98 x107). Very good retrieval success occurred for the O2-A atmospheric absorption feature on the declining NIR shoulder centered at 760 nm (r2 = 0.88, RMSE = 7.54 x 107). When perfect retrievals were assumed (0% noise), retrievals remained good in the low emission regions on either side of the peaks-- those associated with the H alpha line at 655 nm (r2 = 0.83, RMSE =8.87 x 107) and the far-NIR wavelengths recently utilized for satellite retrievals: a K line at 770 nm (r2 = 0.85, RMSE = 8.36 x 107) and the 750-770 nm interval (r2 = 0.88, RMSE = 6.92 x 107). However, the atmosphere and satellite observations are expected to add noise to retrievals. Adding 5% random error to these relationships did not seriously impair the retrieval successes in the red and far-red peaks (r2 ~ 0.85, RMSEs = 6.31 x 107). A greater impact occurred (reducing retrieval success by ~10%) when adding 5% noise for the far-NIR narrow band at 770 nm (r2 ~ 0.70, RMSE ~ 8.5 x 107). When a 10% random error was added, the retrieval successes fell to ~68 ± 7% for all retrieval wavebands, and RMSEs increased by a factor of 10. This laboratory approach will be critical to calibrate space borne retrievals, but additional information across plant species is needed. Furthermore, this experiment indicates that ChlF retrievals from space should include information from the red and far-red peak emission regions, since the true total fluorescence signal is the desired parameter for Earth carbon and energy budgets.

Middleton, E.; Zhang, Q.; Campbell, P. K.; Huemmrich, K. F.; Corp, L.; Cheng, Y.

2012-12-01

79

Specific absorption spectra of hemoglobin at different PO2 levels: potential noninvasive method to detect PO2 in tissues  

NASA Astrophysics Data System (ADS)

Hemoglobin (Hb), as one of main components of blood, has a unique quaternary structure. Its release of oxygen is controlled by oxygen partial pressure (PO2). We investigate the specific spectroscopic changes in Hb under different PO2 levels to optimize clinical methods of measuring tissue PO2. The transmissivity of Hb under different PO2 levels is measured with a UV/Vis fiber optic spectrometer. Its plotted absorption spectral curve shows two high absorption peaks at 540 and 576 nm and an absorption valley at 560 nm when PO2 is higher than 100 mm Hg. The two high absorption peaks decrease gradually with a decrease in PO2, whereas the absorption valley at 560 nm increases. When PO2 decreases to approximately 0 mm Hg, the two high absorption peaks disappear completely, while the absorption valley has a hypochromic shift (8 to 10 nm) and forms a specific high absorption peak at approximately 550 nm. The same phenomena can be observed in visible reflectance spectra of finger-tip microcirculation. Specific changes in extinction coefficient and absorption spectra of Hb occur along with variations in PO2, which could be used to explain pathological changes caused by tissue hypoxia and for early detection of oxygen deficiency diseases in clinical monitoring.

Liu, Peipei; Zhu, Zhirong; Zeng, Changchun; Nie, Guang

2012-12-01

80

Exact results for the spectra of interacting bosons and fermions on the lowest Landau level  

NASA Astrophysics Data System (ADS)

A system of N interacting bosons or fermions in a two-dimensional harmonic potential (or, equivalently, magnetic field) whose states are projected onto the lowest Landau level is considered. Generic expressions are derived for the matrix elements of any interaction, in the basis of angular momentum eigenstates. For the fermion ‘ground state’ (? = 1 Laughlin state), this makes it possible to exactly calculate its energy all the way up to the mesoscopic regime N ? 1000. It is also shown that for N = 3 and Coulomb interaction, several rational low-lying values of energy exist, for bosons and fermions alike.

Mashkevich, Stefan; Matveenko, Sergey; Ouvry, Stéphane

2013-02-01

81

Extremely low-frequency electromagnetic fields affect transcript levels of neuronal differentiation-related genes in embryonic neural stem cells.  

PubMed

Previous studies have reported that extremely low-frequency electromagnetic fields (ELF-EMF) can affect the processes of brain development, but the underlying mechanism is largely unknown. The proliferation and differentiation of embryonic neural stem cells (eNSCs) is essential for brain development during the gestation period. To date, there is no report about the effects of ELF-EMF on eNSCs. In this paper, we studied the effects of ELF-EMF on the proliferation and differentiation of eNSCs. Primary cultured eNSCs were treated with 50 Hz ELF-EMF; various magnetic intensities and exposure times were applied. Our data showed that there was no significant change in cell proliferation, which was evaluated by cell viability (CCK-8 assay), DNA synthesis (Edu incorporation), average diameter of neurospheres, cell cycle distribution (flow cytometry) and transcript levels of cell cycle related genes (P53, P21 and GADD45 detected by real-time PCR). When eNSCs were induced to differentiation, real-time PCR results showed a down-regulation of Sox2 and up-regulation of Math1, Math3, Ngn1 and Tuj1 mRNA levels after 50 Hz ELF-EMF exposure (2 mT for 3 days), but the percentages of neurons (Tuj1 positive cells) and astrocytes (GFAP positive cells) were not altered when detected by immunofluorescence assay. Although cell proliferation and the percentages of neurons and astrocytes differentiated from eNSCs were not affected by 50 Hz ELF-EMF, the expression of genes regulating neuronal differentiation was altered. In conclusion, our results support that 50 Hz ELF-EMF induce molecular changes during eNSCs differentiation, which might be compensated by post-transcriptional mechanisms to support cellular homeostasis. PMID:24595264

Ma, Qinlong; Deng, Ping; Zhu, Gang; Liu, Chuan; Zhang, Lei; Zhou, Zhou; Luo, Xue; Li, Min; Zhong, Min; Yu, Zhengping; Chen, Chunhai; Zhang, Yanwen

2014-01-01

82

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

2013-05-01

83

Electromagnetically Induced Transparency and Autler-Townes Splitting in a Superconducting Quantum Circuit with a Four-Level V-Type Energy Spectrum  

NASA Astrophysics Data System (ADS)

We investigate electromagnetically induced transparency (EIT) and Autler-Townes splitting (ATS) in a superconducting quantum circuit with a four-level V-type energy spectrum constructed by two coupled superconducting charge qubits. We show that it is possible for this four-level superconducting system to exhibit multiple dips in the absorption spectrum of a probe field, with at most three dips resulting from a combination of two ATS subsystems, which indicates the breakdown of the traditional correspondence between a -level system and dips. It is also shown that the switching from EIT to ATS can be realized in a three-level ladder-type subsystem.

Li, Haichao; Ge, Guoqin; Liao, Lingmin; Feng, Shunbin

2015-02-01

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

Limits on the Time Variation of the Electromagnetic Fine-Structure Constant in the Low Energy Limit from Absorption Lines in the Spectra of Distant Quasars  

Microsoft Academic Search

We present the results of a detailed many-multiplet analysis performed on a new sample of Mgii systems observed in high quality quasar spectra obtained using the Very Large Telescope. The weighted mean value of the variation in alpha derived from our analysis over the redshift range 0.4<=z<=2.3 is Deltaalpha\\/alpha=(-0.06±0.06)×10-5. The median redshift of our sample (z~=1.55) corresponds to a look-back

Raghunathan Srianand; Hum Chand; Patrick Petitjean; Bastien Aracil

2004-01-01

86

Electromagnetic fasteners  

Microsoft Academic Search

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

Randolph W. Crane; Donna J. Marts

1994-01-01

87

Ab Initio Determinations of Photoelectron Spectra Including Vibronic Features: An Upper-Level Undergraduate Physical Chemistry Laboratory  

ERIC Educational Resources Information Center

We present a first-principles determination of the photoelectron spectra of water and hypochlorous acid as a laboratory exercise accessible to students in an undergraduate physical chemistry course. This paper demonstrates the robustness and user-friendliness of software developed for the Franck-Condon factor calculation. While the calculator is…

Lord, Richard L.; Davis, Lisa; Millam, Evan L.; Brown, Eric; Offerman, Chad; Wray, Paul; Green, Susan M. E.

2008-01-01

88

High-resolution core level photoelectron spectra of solid TCNQ: determination of molecular orbital spatial distribution from localized shake-up features  

Microsoft Academic Search

High energy resolution X-ray photoelectron spectra of the N 1s and C 1s core levels of solid tetracyanoquinodimethane (TCNQ) are presented. The N 1s binding energy is determined to be 399.7 eV. A single shake-up satellite is detected 2.6 eV to higher binding energy in the N 1s spectrum. The C 1s spectrum shows two core features and a single

John M. Lindquist; John C. Hemminger

1988-01-01

89

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

90

Ligand-field splittings and core-level linewidths in I 4d photoelectron spectra of iodine molecules  

NASA Astrophysics Data System (ADS)

High-resolution I 4d photoelectron spectra (total instrumental resolution ˜0.06 eV) of seven simple iodine molecules, ICl, IBr, I2, HI, CH3I, CH2I2, and CF3I, have been recorded. Ligand-field splitting (as measured by the asymmetric C20 crystal-field term) splits the 4d3/2 and 4d5/2 lines into a doublet and triplet, respectively. In contrast to Si 2p spectra, the I 4d spectra generally show little evidence for vibrational splitting or broadening. The C20 values, like the binding energies E4d, generally increase as the ligand electronegativity increases. C20 also correlates well with the nuclear field gradient, eqn, as measured by Mössbauer spectroscopy or nuclear quadrupole resonance. For the first time we have been able to study the chemical dependence of the inherent lifetime width of a core hole. We show that the I 4d linewidths generally decrease as the electronegativity of the ligand increases, and as the valence I 5p electron density decreases. We also show that there are large relaxation effects on E4d, C20 and especially the linewidth.

Cutler, J. N.; Bancroft, G. M.; Tan, K. H.

1992-12-01

91

Level 0 to 1 processing of the imaging Fourier transform spectrometer GLORIA: generation of radiometrically and spectrally calibrated spectra  

NASA Astrophysics Data System (ADS)

The Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) is an imaging Fourier transform spectrometer that is capable of operating on various high-altitude research aircraft. It measures the atmospheric emission in the thermal infrared spectral region in limb and nadir geometry. GLORIA consists of a classical Michelson interferometer combined with an infrared camera. The infrared detector has a usable area of 128 × 128 pixels, measuring up to 16 384 interferograms simultaneously. Imaging Fourier transform spectrometers impose a number of challenges with respect to instrument calibration and algorithm development. The optical setup with extremely high optical throughput requires the development of new methods and algorithms for spectral and radiometric calibration. Due to the vast amount of data there is a high demand for scientifically intelligent optimisation of the data processing. This paper outlines the characterisation and processing steps required for the generation of radiometrically and spectrally calibrated spectra. Methods for performance optimisation of the processing algorithm are presented. The performance of the data processing and the quality of the calibrated spectra are demonstrated for measurements collected during the first deployments of GLORIA on aircraft.

Kleinert, A.; Friedl-Vallon, F.; Guggenmoser, T.; Höpfner, M.; Neubert, T.; Ribalda, R.; Sha, M. K.; Ungermann, J.; Blank, J.; Ebersoldt, A.; Kretschmer, E.; Latzko, T.; Oelhaf, H.; Olschewski, F.; Preusse, P.

2014-12-01

92

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

Microsoft Academic Search

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

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

2006-01-01

93

Virtual Electromagnet  

NSDL National Science Digital Library

This is an interactive online activity, in which learners equip a virtual electromagnet and see how many iron filings it can pick up. Learners change various characteristics of the electromagnet including the number of windings, the gage of the wire, the current type (AC or DC), the material used in the wire, and the voltage on the power supply.

The University of California Regents

2014-01-01

94

Electromagnetic Attraction.  

ERIC Educational Resources Information Center

Three activities involving electromagnetism are presented. Discussed are investigations involving the construction of an electromagnet, the effect of the number of turns of wire in the magnet, and the effect of the number of batteries in the circuit. Extension activities are suggested. (CW)

Milson, James L.

1990-01-01

95

The Electromagnetic Spectrum: Projecting Visible Spectra  

NSDL National Science Digital Library

In this activity, students study the range of colors in a visible light spectrum created from either a glass prism or holographic diffraction grating. This activity is in unit 2 of the "Space-Based Astronomy" guide that contains background information, worksheets, assessment activities, extensions, and alignment to national education standards.

96

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  

SciTech Connect

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.

Kilpatrick, M.; Ponds, C.D.

1987-02-01

97

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

98

Theory of Dipole Induced Electromagnetic Transparency  

E-print Network

A detailed theory describing linear optics of vapors comprised of interacting multi-level quantum emitters is proposed. It is shown both by direct integration of Maxwell-Bloch equations and using a simple analytical model that at large densities narrow transparency windows appear in otherwise completely opaque spectra. The existence of such windows is attributed to overlapping resonances. This effect, first introduced for three-level systems in [R. Puthumpally-Joseph, M. Sukharev, O. Atabek and E. Charron, Phys. Rev. Lett. 113, 163603 (2014)], is due to strongly enhanced dipole-dipole interactions at high emitters' densities. The presented theory extends this effect to the case of multilevel systems. The theory is applied to the D1 transitions of interacting Rb-85 atoms. It is shown that at high atomic densities, Rb-85 atoms can behave as three-level emitters exhibiting all the properties of dipole induced electromagnetic transparency. Applications including slow light and laser pulse shaping are also propose...

Puthumpally-Joseph, Raiju; Sukharev, Maxim; Charron, Eric

2015-01-01

99

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

100

Electromagnetic fasteners  

DOEpatents

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

101

Electromagnetic Theory 1 /56 Electromagnetic Theory  

E-print Network

Electromagnetic Theory 1 /56 Electromagnetic Theory Summary: · Maxwell's equations · EM Potentials · Equations of motion of particles in electromagnetic fields · Green's functions · Lienard-Weichert potentials · Spectral distribution of electromagnetic energy from an arbitrarily moving charge #12;Electromagnetic

Bicknell, Geoff

102

The influence of oxygen adsorption on the NEXAFS and core-level XPS spectra of the C60 derivative PCBM.  

PubMed

Fullerenes have been a main focus of scientific research since their discovery due to the interesting possible applications in various fields like organic photovoltaics (OPVs). In particular, the derivative [6,6]-phenyl-C60-butyric acid methyl ester (PCBM) is currently one of the most popular choices due to its higher solubility in organic solvents compared to unsubstituted C60. One of the central issues in the field of OPVs is device stability, since modules undergo deterioration (losses in efficiency, open circuit voltage, and short circuit current) during operation. In the case of fullerenes, several possibilities have been proposed, including dimerization, oxidation, and impurity related deterioration. We have studied by means of density functional theory the possibility of oxygen adsorption on the C60 molecular moiety of PCBM. The aim is to provide guidelines for near edge X-ray absorption fine structure (NEXAFS) and X-ray photoelectron spectroscopy (XPS) measurements which can probe the presence of atomic or molecular oxygen on the fullerene cage. By analysing several configurations of PCBM with one or more adsorbed oxygen atoms, we show that a joint core level XPS and O1s NEXAFS investigation could be effectively used not only to confirm oxygen adsorption but also to pinpoint the bonding configuration and the nature of the adsorbate. PMID:25662644

Brumboiu, Iulia Emilia; Ericsson, Leif; Hansson, Rickard; Moons, Ellen; Eriksson, Olle; Brena, Barbara

2015-02-01

103

Electromagnetic Geometry  

E-print Network

We show that Maxwell's electromagnetism can be mapped into the Born-Infeld theory in a curved space-time, which depends only on the electromagnetic field in a specific way. This map is valid for any value of the two lorentz invariants $F$ and $G$ confirming that we have included all possible solutions of Maxwell's equations. Our result seems to show that specifying the dynamics and the space-time structure of a given theory can be viewed merely as a choice of representation to describe the physical system.

M. Novello; F. T. Falciano; E. Goulart

2011-11-08

104

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

105

Personal radiofrequency electromagnetic field measurements in The Netherlands: exposure level and variability for everyday activities, times of day and types of area.  

PubMed

Knowledge of the exposure to radiofrequency electromagnetic fields is necessary for epidemiological studies on possible health effects. The main goal of this study is to determine the exposure level and spatial and temporal variances during 39 everyday activities in 12 frequency bands used in mobile telecommunication and broadcasting. Therefore, 24 h measurements were gathered from 98 volunteers living in or near Amsterdam and Purmerend, The Netherlands. They carried an activity diary to be kept to the minute, a GPS logger sampling at an interval of 1 s, and an EME Spy exposimeter with a detection limit of 0.0066 mW/m(2) sampling at an interval of 10s in 12 frequency bands. The mean exposure over 24 h, excluding own mobile phone use, was 0.180 mW/m(2). During daytime exposure was about the same, but during night it was about half, and in the evening it was about twice as high. The main contribution to environmental exposure (calling by participant not included) is from calling with mobile phones (37.5%), from cordless DECT phones and their docking stations (31.7%), and from the base stations (12.7%). The exposure to mobile phone base stations increases with the percentage of urban ground use, which is an indication for high people density. In agreement, the highest mean exposure relates to the activities with high people density, such as travelling by public transport, visiting social events, pubs or shopping malls. Exposure at home depends mainly on exposure from people calling in the neighbourhood of the participant and thus on the number of persons in a household. In addition just the possession of DECT docking stations leads to exposure as most models transmit continuously in stand-by. Also wireless internet routers continuously transmit in the WiFi band. Though the highest exposure peaks in the WiFi band, up to 0.265 W/m(2), come from stray radiation of microwave ovens. The mean total exposure largely depends on phone calls of a high exposure level and short duration. These calls lead to potentially high contrasts as well in exposure levels between sessions of the same activity as between persons, thus posing a challenge for personal exposure prediction. PMID:22906414

Bolte, John F B; Eikelboom, Tessa

2012-11-01

106

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...

107

Electromagnetic Survey  

USGS Multimedia Gallery

A USGS hydrologist conducts a near-surface electromagnetic induction survey to characterize the shallow earth. The survey was conducted as part of an applied research effort by the USGS Office of Groundwater Branch of Geophysics at Camp Rell, Connecticut, in 2008....

108

Relaxation of vibrational levels H2O (002, 101, 200): effect of new rate constants on the H2O vibrational level populations and ro-vibrational spectra in the mesosphere and lower thermosphere  

NASA Astrophysics Data System (ADS)

In this work, we investigate the sensitivity of the H2O vibrational level populations and ro-vibrational spectra in the mesosphere and lower thermosphere (MLT) to new values of rate constants for the collision-induced transitions from the upper vibrational levels of H2O molecule. This study contributes to the development of the H2O non-equilibrium radiation model used for water vapor altitude distribution retrieval from the MLT radiation measurements. Our model accounts for 13 excited vibrational states up to energies 7445 cm-1 (the upper levels are 002, 101, 200) [Feofilov et al., 2009]. The model takes into account 54 vibrational-translational (V-T) and vibrational-vibrational (V-V) energy exchange processes at collisions of H2O with N2, O2 and O. The 32 ro-vibrational transitions forming 1.4, 1.9, 2.7, 3.2, 4.7 and 6.3 ?m water vapor radiation bands are considered. Currently, the rate constants of intermolecular transitions between vibrational levels at collisions with N2 and O2 are known only for the transitions (010-000) and (001,100-020). In our model of H2O vibrational level kinetics [Feofilov et al., 2009], we assumed that for all collisional transitions, at which the bending mode quantum number, v2, increases by 2: H2O(v1,v2,v3) + M = H2O(v1-1,v2+2,v3) + M H2O(v1,v2,v3) + M = H2O(v1,v2+2,v3-1) + M (1) the rate constants are equal to that of the process H2O(001, 100) + M = H2O(020) + M. Based on the analysis of currently available experimental and theoretical data, we have updated k, the rate constant of transitions (002, 101)?021 and (101, 200)?120, and estimated the effect of a new rate on the H2O vibrational levels populations and limb radiation spectra. The "upper limit" of the effect was estimated using the same rate constant k for all processes of type (1), excluding process (001, 100)?020. The H2O vibrational levels populations and limb radiation spectra were calculated using the ALI-ARMS non-LTE code [Kutepov et al. 1998; Feofilov and Kutepov, 2012] for characteristic atmospheric conditions and compared with the populations and spectra obtained for "regular" rate constants used in [Feofilov et al., 2009]. References Feofilov A. G., Kutepov A. A., Pesnell W. D., Goldberg R. A., Marshall B. T., Gordley L. L., Garcia-Comas M., Lopez-Puertas M., Manuilova R. O., Yankovsky V. A., Petelina S. V., Russell J. M. III. Daytime SABER/TIMED observations of water vapor in the mesosphere: retrieval approach and first results, Atmospheric Chemistry and Physics, V 9, N 21, P 8139-8158, 2009. Kutepov, A. A., Gusev, O. A., and Ogibalov, V. P., Solution of the non-LTE problem for molecular gas in planetary atmospheres: Superiority of accelerated lambda iteration, J. Quant. Spectrosc. Radiat. Transf. V 60, P 199, 1998. Feofilov, A.G., and Kutepov, A., A., "Infrared Radiation in the Mesosphere and Lower Thermosphere: Energetic Effects and Remote Sensing", Surveys in Geophysics, doi:10.1007/s10712-012-9204-0, 2012.

Manuilova, Rada; Feofilov, Artem; Kutepov, Alexander; Yankovsky, Valentine

2014-05-01

109

Parmeterization of spectra  

NASA Technical Reports Server (NTRS)

Following reception and analog to digital conversion (A/D) conversion, atmospheric radar backscatter echoes need to be processed so as to obtain desired information about atmospheric processes and to eliminate or minimize contaminating contributions from other sources. Various signal processing techniques have been implemented at mesosphere-stratosphere-troposphere (MST) radar facilities to estimate parameters of interest from received spectra. Such estimation techniques need to be both accurate and sufficiently efficient to be within the capabilities of the particular data-processing system. The various techniques used to parameterize the spectra of received signals are reviewed herein. Noise estimation, electromagnetic interference, data smoothing, correlation, and the Doppler effect are among the specific points addressed.

Cornish, C. R.

1983-01-01

110

Analytical method of spectra calculations in the Bargmann representation  

E-print Network

We formulate a universal method for solving an arbitrary quantum system which, in the Bargmann representation, is described by a system of linear equations with one independent variable, such as one- and multi-photon Rabi models, or $N$ level systems interacting with a single mode of the electromagnetic field and their various generalizations. We explain three types of conditions that determine the spectrum and show their usage for two deformations of the Rabi model. We prove that the spectra of both models are just zeros of transcendental functions, which in one case are given explicitly in terms of confluent Heun functions.

Andrzej J. Maciejewski; Maria Przybylska; Tomasz Stachowiak

2014-10-31

111

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.

Halbach, Klaus (Berkeley, CA)

1988-01-01

112

Dipole-Induced Electromagnetic Transparency  

E-print Network

We determine the optical response of a thin and dense layer of interacting quantum emitters. We show that in such a dense system, the Lorentz redshift and the associated interaction broadening can be used to control the transmission and reflection spectra. In the presence of overlapping resonances, a Dipole-Induced Electromagnetic Transparency (DIET) regime, similar to Electromagnetically Induced Transparency (EIT), may be achieved. DIET relies on destructive interference between the electromagnetic waves emitted by quantum emitters. Carefully tuning material parameters allows to achieve narrow transmission windows in otherwise completely opaque media. We analyze in details this coherent and collective effect using a generalized Lorentz model and show how it can be controlled. Several potential applications of the phenomenon, such as slow light, are proposed.

Raiju Puthumpally-Joseph; Maxim Sukharev; Osman Atabek; Eric Charron

2014-07-08

113

Dipole-induced electromagnetic transparency.  

PubMed

We determine the optical response of a thin and dense layer of interacting quantum emitters. We show that, in such a dense system, the Lorentz redshift and the associated interaction broadening can be used to control the transmission and reflection spectra. In the presence of overlapping resonances, a dipole-induced electromagnetic transparency (DIET) regime, similar to electromagnetically induced transparency (EIT), may be achieved. DIET relies on destructive interference between the electromagnetic waves emitted by quantum emitters. Carefully tuning material parameters allows us to achieve narrow transmission windows in, otherwise, completely opaque media. We analyze in detail this coherent and collective effect using a generalized Lorentz model and show how it can be controlled. Several potential applications of the phenomenon, such as slow light, are proposed. PMID:25361258

Puthumpally-Joseph, Raiju; Sukharev, Maxim; Atabek, Osman; Charron, Eric

2014-10-17

114

Dipole-Induced Electromagnetic Transparency  

NASA Astrophysics Data System (ADS)

We determine the optical response of a thin and dense layer of interacting quantum emitters. We show that, in such a dense system, the Lorentz redshift and the associated interaction broadening can be used to control the transmission and reflection spectra. In the presence of overlapping resonances, a dipole-induced electromagnetic transparency (DIET) regime, similar to electromagnetically induced transparency (EIT), may be achieved. DIET relies on destructive interference between the electromagnetic waves emitted by quantum emitters. Carefully tuning material parameters allows us to achieve narrow transmission windows in, otherwise, completely opaque media. We analyze in detail this coherent and collective effect using a generalized Lorentz model and show how it can be controlled. Several potential applications of the phenomenon, such as slow light, are proposed.

Puthumpally-Joseph, Raiju; Sukharev, Maxim; Atabek, Osman; Charron, Eric

2014-10-01

115

Electromagnetic Reciprocity.  

SciTech Connect

A reciprocity theorem is an explicit mathematical relationship between two different wavefields that can exist within the same space - time configuration. Reciprocity theorems provi de the theoretical underpinning for mod ern full waveform inversion solutions, and also suggest practical strategies for speed ing up large - scale numerical modeling of geophysical datasets . In the present work, several previously - developed electromagnetic r eciprocity theorems are generalized to accommodate a broader range of medi um, source , and receiver types. Reciprocity relations enabling the interchange of various types of point sources and point receivers within a three - dimensional electromagnetic model are derived. Two numerical modeling algorithms in current use are successfully tested for adherence to reciprocity. Finally, the reciprocity theorem forms the point of departure for a lengthy derivation of electromagnetic Frechet derivatives. These mathe matical objects quantify the sensitivity of geophysical electromagnetic data to variatio ns in medium parameters, and thus constitute indispensable tools for solution of the full waveform inverse problem. ACKNOWLEDGEMENTS Sandia National Labor atories is a multi - program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the US Department of Energy's National Nuclear Security Administration under contract DE - AC04 - 94AL85000. Signif icant portions of the work reported herein were conducted under a Cooperative Research and Development Agreement (CRADA) between Sandia National Laboratories (SNL) and CARBO Ceramics Incorporated. The author acknowledges Mr. Chad Cannan and Mr. Terry Pa lisch of CARBO Ceramics, and Ms. Amy Halloran, manager of SNL's Geophysics and Atmospheric Sciences Department, for their interest in and encouragement of this work. Special thanks are due to Dr . Lewis C. Bartel ( recently retired from Sandia National Labo ratories and now a geophysical consultant ) and Dr. Chester J. Weiss (recently rejoined with Sandia National Laboratories) for many stimulating (and reciprocal!) discussions regar ding the topic at hand.

Aldridge, David F.

2014-11-01

116

atomic spectra 1 Atomic Spectra  

E-print Network

Physics, pp. 88-93 (Rutherford nuclear model), 93-106 (atomic structure and electron spectra) 2. D. W 3. Beiser: Concepts of Modern Physics, pp. 131-161 (atomic structure and electron spectra) 4. E. Lamb, Jr. and R. C. Retherford: The Structure of the Hydrogen Atom by a Microwave Method, Phys

Glashausser, Charles

117

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

118

Spontaneous emission of a two-level static atom coupling with the electromagnetic vacuum fluctuations outside a high-dimensional Einstein Gauss-Bonnet black hole  

E-print Network

In present paper, by using the generalized DDC formalism, we investigate the spontaneous excitation of an static atom interacting with electromagnetic vacuum fluctuations outside a EGB black hole in $d$-dimensions. We find that spontaneous excitation does not occur in Boulware vacuum. The Gauss-Bonnet term has no effect on the stability of the atom. Finally, we discuss the contribution of the coupling constant and dimensional factor to the results in three different kinds of spacetime.

Ming Zhang; Zhan-Ying Yang; Rui-Hong Yue

2014-07-04

119

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

120

Effect of the pumping-field amplitude and phase modulation on the weak-probe absorption and dispersion spectra in a two-level medium  

NASA Astrophysics Data System (ADS)

The analytic solutions of equations, which describe the time behavior of density-matrix elements of a two-level medium driven by weak-probe tunable and strong fields, namely, scrE(t)=E(t)cos[?t+?(t)]+? cos[(?+?)t], the amplitude E(t) and phase ?(t) of which are any arbitrary functions of time, are obtained. We obtain explicit expressions of the medium polarizability in two cases of the strong-field parameters modulation: first, E(t)=E0cos(? cos?t), where E0, ?, and ? are constants, and ?=0 and second, both the amplitude E(t) and the phase ?(t) are periodic functions of time, and E(t)=C??, where C is an arbitrary constant. These cases of modulation are generalizations of cases that were considered earlier. The first case of modulation causes a shift of the well-known Rabi resonances in the weak-probe absorption and dispersion spectra by the factor J0(?) (J0 is the zero-order Bessel function of the first kind) in comparison with a nonmodulated exciting field. In the second case of the modulation, the Rabi resonances are present but the effect of such a modulation results in an attenuation of the amplitude-modulation effect. The values of the parameters E0, ?, C, and ? and the frequency ranges in which the weak-probe gain, caused by resonant Rayleigh scattering and by three-photon scattering, takes place are determined for these two cases of the modulation.

Alekseev, A. V.; Kholodkevich, E. D.; Sushilov, N. V.; Zinin, Yu. A.

1994-06-01

121

Creating an Electromagnet  

NSDL National Science Digital Library

Student teams investigate the properties of electromagnets. They create their own small electromagnet and experiment with ways to change its strength to pick up more paper clips. Students learn about ways that engineers use electromagnets in everyday applications.

Integrated Teaching And Learning Program

122

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.

123

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

124

Electromagnetic topology: Characterization of internal electromagnetic coupling  

NASA Technical Reports Server (NTRS)

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 derivations of the scattering parameters are presented. These concepts are used to study the electromagnetic coupling in a scale model of an aircraft, and can be seen as a convenient means to test internal electromagnetic interference.

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

1991-01-01

125

Experimental investigation of the ionospheric hysteresis effect on the threshold excitation level of the Stimulated Electromagnetic Emission (SEE) during heating at the second electron gyro-harmonic frequency  

NASA Astrophysics Data System (ADS)

Recent experimental observations of the stimulated electromagnetic emission (SEE) spectrum during heating at the second electron gyro-harmonic show structures ordered by ion gyro-frequency. The proposed generation mechanism considers parametric decay of a pump upper hybrid/electron Bernstein (UH/EB) wave into another UH/EB and a group of neutralized ion Bernstein waves. The presumption of the proposed mechanism is that the pump electromagnetic wave is converted into the UH/EB wave. This conversion process generates field aligned irregularity which exhibits hysteresis effect. The predicted ionospheric hysteresis effect is studied during the PARS 2012 at HAARP. The preliminary results are presented for the first time. Also, experimental study of the effects of 1) the transmitter beam angle and 2) the transmitter frequency offset relative to the second electron gyro-harmonic frequency on the ion gyro-harmonic structures in the SEE spectrum are provided. The aforementioned observations are compared to the predictions of the analytical model. Possible connection of the SEE spectral features and artificially generated ionospheric descending layer is also discussed

Samimi, A.; Scales, W.; Cruz, M.; Isham, B.; Bernhardt, P. A.

2012-12-01

126

Electromagnetic Field Theory  

E-print Network

Electromagnetic Field Theory BO THID� UPSILON BOOKS #12;#12;ELECTROMAGNETIC FIELD THEORY #12;#12;Electromagnetic Field Theory BO THID� Swedish Institute of Space Physics and Department of Astronomy and Space, Sweden UPSILON BOOKS · COMMUNA AB · UPPSALA · SWEDEN #12;Also available ELECTROMAGNETIC FIELD THEORY

Hart, Gus

127

Classification of intentional electromagnetic environments (IEME)  

Microsoft Academic Search

One can classify potential intentional electromagnetic environments (IEME) threat environments into four categories, based on frequency coverage. Yet another way of categorizing IEME is based on the level of sophistication of the underlying technologies involved in producing the electromagnetic environment, as low, medium, and high-tech systems. A third way of classifying IEME is by the effects that it can have

D. V. Giri; F. M. Tesche

2004-01-01

128

Gravito-electromagnetic resonances in Minkowski space  

NASA Astrophysics Data System (ADS)

We consider the interaction between gravitational and electromagnetic radiation propagating on a Minkowski background and look into the effects of the former upon the latter. Not surprisingly, the coupling between these two sources leads to gravitationally driven electromagnetic waves. At the second perturbative level, the driving force appears as the superposition of two waves, the properties of which are decided by the initial conditions. We find that the Weyl-Maxwell interaction typically leads to electromagnetic beatlike signals and, in some cases, to the resonant amplification of the driven electromagnetic wave. For physically reasonable initial conditions, we show that these resonances imply a linear (in time) growth for the amplitude of the electromagnetic signal, with the overall amplification also depending on the strength of the driving gravity wave. Finally, we provide order-of-magnitude estimates of the achieved amplification by applying our analysis to astrophysical environments where both gravitational and electromagnetic waves are expected to coexist.

Kouretsis, Alexandros P.; Tsagas, Christos G.

2013-08-01

129

Spontaneous Emission of a Two-Level Static Atom Coupling with Electromagnetic Vacuum Fluctuations Outside a High-Dimensional Einstein Gauss–Bonnet Black Hole  

NASA Astrophysics Data System (ADS)

Using the generalized formalism of Dalibard, Dupont–Roc and Cohen–Tannoudji we investigate the spontaneous excitation of a static atom interacting with electromagnetic vacuum fluctuations outside an Einstein Gauss–Bonnet black hole in d-dimensions. It shows that spontaneous excitation does not occur in a Boulware vacuum, while exists in an Unruh vacuum and Hartle–Hawking vacuum. As to the total rate of change of the atomic energy, it does not receive the contribution from the coupling constant of the Gauss–Bonnet term at spatial infinity only the dimensional parameter has the contribution to it. Near the event horizon, both the coupling constant and the dimension p contribute to the total rate of change of the atomic energy in all three kinds of vacuum. We discuss the contribution of the coupling constant and dimensional factor to the results in three different kinds of spacetime lastly.

Zhang, Ming; Yang, Zhan-Ying; Yue, Rui-Hong

2014-10-01

130

An analysis of VLF electric field spectra measured in Titan's atmosphere by the Huygens probe  

Microsoft Academic Search

A numerical simulation of Titan's electromagnetic cavity in the VLF band is carried out using the Transmission Line Matrix (TLM) method, with the aim of assessing the VLF electric field spectra sent by the Huygens probe. In an Earth-like model, successive peaks would be expected in the spectra, associated with multiple reflections of the electromagnetic wave on the external surfaces

Juan A. Morente; Jorge A. Portí; Cedric Blanchard; Enrique A. Navarro; Alfonso Salinas

2009-01-01

131

ECE 203 Spring 2012 Engineering Electromagnetics Waves (3)  

E-print Network

ECE 203 ­ Spring 2012 Engineering Electromagnetics Waves (3) Lecture Time: Spring 2012, Monday Required Reading Textbook: 1. S. M. Wentworth, Applied Electromagnetic, Wiley (2007). 2. Nelson Tansu, and A. S. Inan, Electromagnetic Waves, Prentice Hall (2000). Useful EM textbook for ECE 203-level. 2. D

Gilchrist, James F.

132

7. Electromagnetic relations 1 7. ELECTROMAGNETIC RELATIONS  

E-print Network

7. Electromagnetic relations 1 7. ELECTROMAGNETIC RELATIONS Revised September 2005 by H.G. Spieler = 10-7 N A-2 ; c = 1 0 0 = 2.997 924 58 Ã? 108 m s-1 #12;2 7. Electromagnetic relations 7.1. Impedances of self-inductance L: Z = jL . Impedance of capacitance C: Z = 1/jC . Impedance of free space: Z = 0/ 0

133

Perturbations in electromagnetic dark energy  

SciTech Connect

It has been recently proposed that the presence of a temporal electromagnetic field on cosmological scales could explain the phase of accelerated expansion that the universe is currently undergoing. The field contributes as a cosmological constant and therefore, the homogeneous cosmology produced by such a model is exactly the same as that of ?CDM. However, unlike a cosmological constant term, electromagnetic fields can acquire perturbations which in principle could affect CMB anisotropies and structure formation. In this work, we study the evolution of inhomogeneous scalar perturbations in this model. We show that provided the initial electromagnetic fluctuations generated during inflation are small, the model is perfectly compatible with both CMB and large scale structure observations at the same level of accuracy as ?CDM.

Jiménez, Jose Beltrán; Maroto, Antonio L. [Departamento de Física Teórica, Universidad Complutense de Madrid, 28040 Madrid (Spain); Koivisto, Tomi S. [Institute for Theoretical Physics, University of Heidelberg, 69120 Heidelberg (Germany); Mota, David F., E-mail: jobeltra@fis.ucm.es, E-mail: T.Koivisto@thphys.uni-heidelberg.de, E-mail: maroto@fis.ucm.es, E-mail: d.f.mota@astro.uio.no [Institute of Theoretical Astrophysics, University of Oslo, 0315 Oslo (Norway)

2009-10-01

134

Perturbations in electromagnetic dark energy  

E-print Network

It has been recently proposed that the presence of a temporal electromagnetic field on cosmological scales could explain the phase of accelerated expansion that the universe is currently undergoing. The field contributes as a cosmological constant and therefore, the homogeneous cosmology produced by such a model is exactly the same as that of $\\Lambda$CDM. However, unlike a cosmological constant term, electromagnetic fields can acquire perturbations which in principle could affect CMB anisotropies and structure formation. In this work, we study the evolution of inhomogeneous scalar perturbations in this model. We show that provided the initial electromagnetic fluctuations generated during inflation are small, the model is perfectly compatible with both CMB and large scale structure observations at the same level of accuracy as $\\Lambda$CDM.

Jose Beltran Jimenez; Tomi S. Koivisto; Antonio L. Maroto; David F. Mota

2009-07-21

135

Gallium Electromagnetic (GEM) Thruster Performance Measurements  

NASA Technical Reports Server (NTRS)

Discharge current, terminal voltage, and mass bit measurements are performed on a coaxial gallium electromagnetic thruster at discharge currents in the range of 7-23 kA. It is found that the mass bit varies quadratically with the discharge current which yields a constant exhaust velocity of 20 km/s. Increasing the electrode radius ratio of the thruster from to 2.6 to 3.4 increases the thruster efficiency from 21% to 30%. When operating with a central gallium anode, macroparticles are ejected at all energy levels tested. A central gallium cathode ejects macroparticles when the current density exceeds 3.7 10(exp 8) A/square m . A spatially and temporally broad spectroscopic survey in the 220-520 nm range is used to determine which species are present in the plasma. The spectra show that neutral, singly, and doubly ionized gallium species are present in the discharge, as well as annular electrode species at higher energy levels. Axial Langmuir triple probe measurements yield electron temperatures in the range of 0.8-3.8 eV and electron densities in the range of 8 x 10(exp )20 to 1.6 x 10(exp 21) m(exp -3) . Triple probe measurements suggest an exhaust plume with a divergence angle of 9 , and a completely doubly ionized plasma at the ablating thruster cathode.

Thomas, Robert E.; Burton, Rodney L.; Polzin, K. A.

2009-01-01

136

Effects of whole body exposure to extremely low frequency electromagnetic fields (ELF-EMF) on serum and liver lipid levels, in the rat  

PubMed Central

Backgound The effects of extremely low-frequency electromagnetic fields (ELF-EMF) on the blood serum and liver lipid concentrations of male Wistar rats were assessed. Methods Animals were exposed to a single stimulation (2 h) of ELF-EMF (60 Hz, 2.4 mT) or sham-stimulated and thereafter sacrificed at different times (24, 48 or 96 h after beginning the exposure). Results Blood lipids showed, at 48 h stimulated animals, a significant increase of cholesterol associated to high density lipoproteins (HDL-C) than those observed at any other studied time. Free fatty acid serum presented at 24 h significant increases in comparison with control group. The other serum lipids, triacylglycerols and total cholesterol did not show differences between groups, at any time evaluated. No statistical differences were shown on total lipids of the liver but total cholesterol was elevated at 24 h with a significant decrease at 96 h (p = 0.026). The ELF-EMF stimulation increased the liver content of lipoperoxides at 24 h. Conclusion Single exposures to ELF-EMF increases the serum values of HDL-C, the liver content of lipoperoxides and decreases total cholesterol of the liver. The mechanisms for the effects of ELF-EMF on lipid metabolism are not well understand yet, but could be associated to the nitric oxide synthase EMF-stimulation. PMID:18021407

Torres-Duran, Patricia V; Ferreira-Hermosillo, Aldo; Juarez-Oropeza, Marco A; Elias-Viñas, David; Verdugo-Diaz, Leticia

2007-01-01

137

Carbon X-ray absorption spectra of fluoroethenes and acetone: a study at the coupled cluster, density functional, and static-exchange levels of theory.  

PubMed

Near carbon K-edge X-ray absorption fine structure spectra of a series of fluorine-substituted ethenes and acetone have been studied using coupled cluster and density functional theory (DFT) polarization propagator methods, as well as the static-exchange (STEX) approach. With the complex polarization propagator (CPP) implemented in coupled cluster theory, relaxation effects following the excitation of core electrons are accounted for in terms of electron correlation, enabling a systematic convergence of these effects with respect to electron excitations in the cluster operator. Coupled cluster results have been used as benchmarks for the assessment of propagator methods in DFT as well as the state-specific static-exchange approach. Calculations on ethene and 1,1-difluoroethene illustrate the possibility of using nonrelativistic coupled cluster singles and doubles (CCSD) with additional effects of electron correlation and relativity added as scalar shifts in energetics. It has been demonstrated that CPP spectra obtained with coupled cluster singles and approximate doubles (CC2), CCSD, and DFT (with a Coulomb attenuated exchange-correlation functional) yield excellent predictions of chemical shifts for vinylfluoride, 1,1-difluoroethene, trifluoroethene, as well as good spectral features for acetone in the case of CCSD and DFT. Following this, CPP-DFT is considered to be a viable option for the calculation of X-ray absorption spectra of larger ?-conjugated systems, and CC2 is deemed applicable for chemical shifts but not for studies of fine structure features. The CCSD method as well as the more approximate CC2 method are shown to yield spectral features relating to ??-resonances in good agreement with experiment, not only for the aforementioned molecules but also for ethene, cis-1,2-difluoroethene, and tetrafluoroethene. The STEX approach is shown to underestimate ??-peak separations due to spectral compressions, a characteristic which is inherent to this method. PMID:23556727

Fransson, Thomas; Coriani, Sonia; Christiansen, Ove; Norman, Patrick

2013-03-28

138

Electromagnetic induction methods  

Technology Transfer Automated Retrieval System (TEKTRAN)

Electromagnetic induction geophysical methods are finding greater and greater use for agricultural purposes. Electromagnetic induction methods measure the electrical conductivity (or resistivity) for a bulk volume of soil directly beneath the surface. An instrument called a ground conductivity meter...

139

Electromagnetic properties of neutrinos  

E-print Network

A short review on electromagnetic properties of neutrinos is presented. In spite of many efforts in the theoretical and experimental studies of neutrino electromagnetic properties, they still remain one of the main puzzles related to neutrinos.

Carlo Giunti; Alexander Studenikin

2010-06-08

140

Electromagnetic Properties for Arbitrary Spin Particles: Part 1 $-$ Electromagnetic Current and Multipole Decomposition  

E-print Network

In a set of two papers, we propose to study an old-standing problem, namely the electromagnetic interaction for particles of arbitrary spin. Based on the assumption that light-cone helicity at tree level and $Q^2=0$ should be conserved non-trivially by the electromagnetic interaction, we are able to derive \\emph{all} the natural electromagnetic moments for a pointlike particle of \\emph{any} spin. In this first paper, we propose a transparent decomposition of the electromagnetic current in terms of covariant vertex functions. We also define in a general way the electromagnetic multipole form factors, and show their relation with the electromagnetic moments. Finally, by considering the Breit frame, we relate the covariant vertex functions to multipole form factors.

Cédric Lorcé

2009-01-27

141

Electromagnetic Abdulaziz Hanif  

E-print Network

Electromagnetic Propulsion Abdulaziz Hanif Electrical Engineering Department King Fahd University of spacecraft, which would be jolted through space by electromagnets, could take us farther than any of these other methods. When cooled to extremely low temperatures, electromagnets demonstrate an unusual behavior

Masoudi, Husain M.

142

Electromagnetic Measurements at RHIC  

E-print Network

Electromagnetic Measurements at RHIC Hideki Hamagaki Center for Nuclear Study University of Tokyo #12;2/10/2005 "Electromagnetic measurements at RHIC"@ICPAQGP 05 Hideki Hamagaki 2 Prologue · EM probe and where they are produced; #12;2/10/2005 "Electromagnetic measurements at RHIC"@ICPAQGP 05 Hideki Hamagaki

Hamagaki, Hideki

143

Electromagnetic Measurements at RHIC  

E-print Network

Electromagnetic Measurements at RHIC Hideki Hamagaki Center for Nuclear Study Graduate School of Science the University of Tokyo #12;2006/06/29 "Electromagnetic measurements at RHIC"@ATHIC 2006 Hideki;2006/06/29 "Electromagnetic measurements at RHIC"@ATHIC 2006 Hideki Hamagaki 3 Prologue ­ scope of EM measurements · EM

Hamagaki, Hideki

144

Avionics electromagnetic interference immunity and environment  

NASA Technical Reports Server (NTRS)

Aircraft electromagnetic spectrum and radio frequency (RF) field strengths are charted, profiling the higher levels of electromagnetic voltages encountered by the commercial aircraft wiring. Selected military, urban, and rural electromagnetic field levels are plotted and provide a comparison of radiation amplitudes. Low frequency magnetic fields and electric fields from 400 H(Z) power systems are charted versus frequency and wire separation to indicate induced voltages on adjacent or neighboring circuits. Induced EMI levels and attenuation characteristics of electric, magnetic, RF fields, and transients are plotted and graphed for common types of wire circuits. The significance of wire circuit returns and shielding is emphasized to highlight the techniques that help block the paths of electromagnetic interference and maintain avionic interface signal quality.

Clarke, C. A.

1986-01-01

145

Level 2 processing for the imaging Fourier transform spectrometer GLORIA: derivation and validation of temperature and trace gas volume mixing ratios from calibrated dynamics mode spectra  

NASA Astrophysics Data System (ADS)

The Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) is an airborne infrared limb-imager combining a two-dimensional infrared detector with a Fourier transform spectrometer. It was operated aboard the new German Gulfstream G550 research aircraft HALO during the Transport And Composition in the upper Troposphere/lowermost Stratosphere (TACTS) and Earth System Model Validation (ESMVAL) campaigns in summer 2012. This paper describes the retrieval of temperature and trace gas (H2O, O3, HNO3) volume mixing ratios from GLORIA dynamics mode spectra. 26 integrated spectral windows are employed in a joint fit to retrieve seven targets using consecutively a fast and an accurate tabulated radiative transfer model. Typical diagnostic quantities are provided including effects of uncertainties in the calibration and horizontal resolution along the line-of-sight. Simultaneous in-situ observations by the BAsic HALO Measurement And Sensor System (BAHAMAS), the Fast In-Situ Stratospheric Hygrometer (FISH), FAIRO, and the Atmospheric chemical Ionization Mass Spectrometer (AIMS) allow a validation of retrieved values for three flights in the upper troposphere/lowermost stratosphere region spanning polar and sub-tropical latitudes. A high correlation is achieved between the remote sensing and the in-situ trace gas data, and discrepancies can to a large fraction be attributed to differences in the probed air masses caused by different sampling characteristics of the instruments. This 1-D processing of GLORIA dynamics mode spectra provides the basis for future tomographic inversions from circular and linear flight paths to better understand selected dynamical processes of the upper troposphere and lowermost stratosphere.

Ungermann, J.; Blank, J.; Dick, M.; Ebersoldt, A.; Friedl-Vallon, F.; Giez, A.; Guggenmoser, T.; Höpfner, M.; Jurkat, T.; Kaufmann, M.; Kaufmann, S.; Kleinert, A.; Krämer, M.; Latzko, T.; Oelhaf, H.; Olchewski, F.; Preusse, P.; Rolf, C.; Schillings, J.; Suminska-Ebersoldt, O.; Tan, V.; Thomas, N.; Voigt, C.; Zahn, A.; Zöger, M.; Riese, M.

2014-12-01

146

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

147

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.

148

Electromagnetically revolving sphere viscometer  

NASA Astrophysics Data System (ADS)

In this paper, we propose a new method of low viscosity measurement, in which the rolling of a probe sphere on the flat solid bottom of a sample cell is driven remotely and the revolution speed of the probe in a sample liquid gives the viscosity measurements. The principle of this method is based on the electromagnetically spinning technique that we developed, and the method is effective especially for viscosity measurements at levels below 100 mPa·s with an accuracy higher than 1%. The probe motion is similar to that in the well-known rolling sphere (ball) method. However, our system enables a steady and continuous measurement of viscosity, which is problematic using the conventional method. We also discuss the limits of the measurable viscosity range common to rolling-sphere-type viscometers by considering the accelerating motion of a probe sphere due to gravity, and we demonstrate the performance of our methods.

Hosoda, Maiko; Sakai, Keiji

2014-12-01

149

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

150

arXiv:nucl-th/001006218Oct2000 Electromagnetic Structure of Few-Nucleon Systems: a Critical Review  

E-print Network

in predicting a number of nuclear properties for systems with mass number A 8, including energy spectra of low-lying states, electromagnetic form factors, and low-energy capture reactions. 2. Interactions and Energy, including energy spectra, electromagnetic form factors, and capture reactions, is critically reviewed within

Thomas Jefferson National Accelerator Facility

151

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

152

Hospital emergency room electromagnetic environment  

Microsoft Academic Search

The electromagnetic environment of the emergency room of an urban hospital was estimated, characterizing electric fields over a 4.4-day period. Measured fields did not exceed 1 V\\/m over the 0.1-1 GHz range, but exhibited substantial day-night variation. Such temporal variation was characterized with respect to intensity and frequency of emissions. The observed field level variation implied a substantial temporal variation

D. Davis; B. Skulic; B. Segal; P. Vlach; T. Pavlasek

1997-01-01

153

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.

154

Project Spectra!  

NSDL National Science Digital Library

This is a digital project developed to advance knowledge of solar system exploration by providing students with spectroscopic data in an accessible and engaging format. The NASA-funded program blends hands-on activities with the use of real data to solve scientific problems. Each lesson is standards-based and includes background information, teacher's guide, student guide with problem sets, and full instructions for accessing all data-driven material. Several lessons include interactive Flash tutorials and inquiry-based "data stories" using authentic data from actual space missions. The activities can be adapted or modified to accommodate a range of course levels and student abilities. Lesson topics include: "Graphing the Rainbow", "Using Spectral Data to Explore Saturn & Titan", "Building a Fancy Spectrograph", "Marvelous Martian Mineralogy", and more.

2012-10-26

155

Two-photon photodissociation of NO through Rydberg levels in the 265-278 nm region: Spectra and photofragment angular distributions  

NASA Astrophysics Data System (ADS)

The spectroscopy and dynamics of the NO photodissociation through Rydberg levels near 74 000 cm-1 have been investigated following two-photon excitation. The 6dpi-)(v=1 and 5ssigma(v=3) levels overlap near 74 070 cm-1. Assignment of the rotational transitions for these levels has been aided by the use of the photoproduct angular distributions measured using product imaging techniques. Product imaging was also used to investigate the 8dpi-)(v=1 and 5ssigma(v=2) regions assigned by previous investigators. In all cases, the major products were N(2)D+O(3)P. The angular distributions vary strongly with rotational transition and with the assumed intermediate in the two-photon excitation scheme and can, for the most part, be predicted by calculation. They demonstrate that, for the Rydberg levels examined, the major contribution to the two-photon line strength is a Pi intermediate, likely the C 2Pi state, with less than a 30% amplitude contribution from either a Sigma or Delta intermediate.

Cosofret, B. R.; Lambert, H. M.; Houston, P. L.

2002-11-01

156

Electromagnetic structure of pion  

SciTech Connect

In this work, we analyze the electromagnetic structure of the pion, an elementary particle composed by a quark-antiquark bound state, by considering the calculation of its electromagnetic radius and its electromagnetic form factor in low and intermediate energy range. Such observables are determined by means of a theoretical model that takes into account the constituent quark and antiquark of the pion, in the formalism of the light-front field theory. In particular, it is considered a nonsymmetrical vertex for such a model, in which we have calculated the electromagnetic form factor of the pion in an optimized way, by varying its regulator mass, so that we can obtain the best value for the pion electromagnetic radius when compared with the experimental one. The theoretical calculations are also compared with the most recent experimental data involving the pion electromagnetic form factor and the results show very good agreement.

Mello, Clayton S.; Cruz Filho, Jose P.; Da Silva, Edson O.; El-Bennich, Bruno; De Melo, J. P.; Filho, Victo S. [Laboratorio de Fisica Teorica e Computacional (LFTC), Universidade Cruzeiro do Sul, 01506-000, Sao Paulo (Brazil)

2013-03-25

157

8.07 Electromagnetism II, Fall 2002  

E-print Network

Survey of basic electromagnetic phenomena: electrostatics, magnetostatics; electromagnetic properties of matter. Time-dependent electromagnetic fields and Maxwell's equations. Electromagnetic waves, emission, absorption, ...

Zwiebach, Barton

158

Exploring the Electromagnetic Spectrum  

NSDL National Science Digital Library

Students learn the basics of the electromagnetic spectrum and how various types of electromagnetic waves are related in terms of wavelength and energy. In addition, they are introduced to the various types of waves that make up the electromagnetic spectrum including, radio waves, ultraviolet waves, visible light and infrared waves. These topics help inform students before they turn to designing solutions to an overarching engineering challenge question.

2014-09-18

159

"Hearing" Electromagnetic Waves  

NASA Astrophysics Data System (ADS)

In this work, an educational experience is described in which a microwave communication link is used to make students aware that all electromagnetic waves have the same physical nature and properties. Experimental demonstrations are linked to theoretical concepts to increase comprehension of the physical principles underlying electromagnetic waves. Moreover, students learn about the importance and historical development of communication systems, the basic principles of communication links, and the procedure to send information through an electromagnetic wave.1,2

Rojo, Marta; Muñoz, Juan

2014-12-01

160

Megawatt Electromagnetic Plasma Propulsion  

NASA Technical Reports Server (NTRS)

The NASA Glenn Research Center program in megawatt level electric propulsion is centered on electromagnetic acceleration of quasi-neutral plasmas. Specific concepts currently being examined are the Magnetoplasmadynamic (MPD) thruster and the Pulsed Inductive Thruster (PIT). In the case of the MPD thruster, a multifaceted approach of experiments, computational modeling, and systems-level models of self field MPD thrusters is underway. The MPD thruster experimental research consists of a 1-10 MWe, 2 ms pulse-forming-network, a vacuum chamber with two 32 diffusion pumps, and voltage, current, mass flow rate, and thrust stand diagnostics. Current focus is on obtaining repeatable thrust measurements of a Princeton Benchmark type self field thruster operating at 0.5-1 gls of argon. Operation with hydrogen is the ultimate goal to realize the increased efficiency anticipated using the lighter gas. Computational modeling is done using the MACH2 MHD code, which can include real gas effects for propellants of interest to MPD operation. The MACH2 code has been benchmarked against other MPD thruster data, and has been used to create a point design for a 3000 second specific impulse (Isp) MPD thruster. This design is awaiting testing in the experimental facility. For the PIT, a computational investigation using MACH2 has been initiated, with experiments awaiting further funding. Although the calculated results have been found to be sensitive to the initial ionization assumptions, recent results have agreed well with experimental data. Finally, a systems level self-field MPD thruster model has been developed that allows for a mission planner or system designer to input Isp and power level into the model equations and obtain values for efficiency, mass flow rate, and input current and voltage. This model emphasizes algebraic simplicity to allow its incorporation into larger trajectory or system optimization codes. The systems level approach will be extended to the pulsed inductive thruster and other electrodeless thrusters at a future date.

Gilland, James; Lapointe, Michael; Mikellides, Pavlos

2003-01-01

161

Meson electromagnetic form factors  

E-print Network

The electromagnetic structure of the pseudoscalar meson nonet is completely described by the sophisticated Unitary&Analytic model, respecting all known theoretical properties of the corresponding form factors.

Stanislav Dubnicka; Anna Z. Dubnickova

2012-10-23

162

How Strong are Electromagnets?  

NSDL National Science Digital Library

This is an activity about electromagnetism. Using a battery and a length of wire, learners will construct an electromagnet and investigate the number of paperclips the electromagnet can hold for an electromagnet with twenty loops of wire versus one with forty loops of wire. A six to twelve volt battery, a large nail or metal rod, and insulated wire are required for this activity. This is the fourth activity in the Exploring the Earth's Magnetic Field: An IMAGE Satellite Guide to the Magnetosphere educators guide.

163

Galaxy and Stellar Spectra  

NSDL National Science Digital Library

In this activity students learn that galaxies shine on the basis of their intergrated stellar population, therefore, adding together different stellar spectra should reproduce the spectra of a galaxy. This activity contains an applet which allows one to add spectra of up to four different stars to produce a resultant spectra. To reproduce qualitatively a spectra of a galaxy one can add together and F main sequence star and a K Giant. The spectra are normalized by V-band luminosity.

Department, University O.

2005-06-17

164

Reemission of ultrashort electromagnetic field pulses by multielectron atoms  

NASA Astrophysics Data System (ADS)

We develop a method for calculating the spectra of reemission of ultrashort (attosecond and shorter) electromagnetic field pulses by neutral multielectron atoms with a nuclear charge from 1 to 92. The method makes it possible to exactly take into account the spatial nonuniformity of the field of an ultrashort pulse and photon momenta in reemission processes. The results are represented as analytical formulas with several coefficients and screening parameters tabulated for all atoms for which the electron densities can be described by the familiar Dirac-Hartree-Fock-Slater model. By way of example, the spectra of remission of ultrashort electromagnetic field pulses by carbon, silicon, germanium, tin, and lead atoms are calculated.

Makarov, D. N.; Matveev, V. I.

2014-10-01

165

Velocity anisotropy effect in pump-probe spectra of cesium in a micrometric thickness optical cell  

NASA Astrophysics Data System (ADS)

The pump-probe spectra in a cell of micrometric thickness containing cesium vapor are reported. The line shape and nonlinear features observed in the case of fluorescence in the direction parallel to the cell windows and the transmission spectra observed along the propagation direction of the probe beam show considerable differences in the spectral profiles. We observed Electromagnetically Induced Transparency (EIT) and enhanced Velocity Selective Optical Pumping (VSOP) signals. Atoms moving nearly parallel to the windows and perpendicular to the collinear pump and probe beams will see much lower Doppler shift of incident frequencies and hence will lead to considerable narrowing of the Doppler background in the fluorescence spectra. The coherence decay rate is also low for such atoms as they do not meet with the cell walls. A theoretical model based on five level optical Bloch equations is used to simulate the spectra. The Doppler convolution includes all possible orientation of atomic velocities with respect to the laser beam direction. The simulated curves reproduce the observed sharp EIT peaks and enhanced broad VSOP signals for the closed probe transition in the fluorescence and absorption spectra. The observed effect of the light intensity and temperature change on the non-linear features is reproduced by the simulation.

Ghosh, P. N.; Mitra, S.; Ray, B.; Krasteva, A.; Slavov, D.; Todorov, P.; Cartaleva, S.

2015-01-01

166

Electromagnetics from a quasistatic perspective  

E-print Network

Quasistatics is introduced so that it fits smoothly into the standard textbook presentation of electrodynamics. The usual path from statics to general electrodynamics is rather short and surprisingly simple. A closer look reveals however that it is not without confusing issues as has been illustrated by many contributions to this Journal. Quasistatic theory is conceptually useful by providing an intermediate level in between statics and the full set of Maxwell's equations. Quasistatics is easier than general electrodynamics and in some ways more similar to statics. It is however, in terms of interesting physics and important applications, far richer than statics. Quasistatics is much used in electromagnetic modeling, an activity that today is possible on a PC and which also has great pedagogical potential. The use of electromagnetic simulations in teaching gives additional support for the importance of quasistatics. This activity may also motivate some change of focus in the presentation of basic electrodynam...

Larsson, J

2006-01-01

167

Electromagnetics from a quasistatic perspective  

E-print Network

Quasistatics is introduced so that it fits smoothly into the standard textbook presentation of electrodynamics. The usual path from statics to general electrodynamics is rather short and surprisingly simple. A closer look reveals however that it is not without confusing issues as has been illustrated by many contributions to this Journal. Quasistatic theory is conceptually useful by providing an intermediate level in between statics and the full set of Maxwell's equations. Quasistatics is easier than general electrodynamics and in some ways more similar to statics. It is however, in terms of interesting physics and important applications, far richer than statics. Quasistatics is much used in electromagnetic modeling, an activity that today is possible on a PC and which also has great pedagogical potential. The use of electromagnetic simulations in teaching gives additional support for the importance of quasistatics. This activity may also motivate some change of focus in the presentation of basic electrodynamics.

Jonas Larsson

2006-06-13

168

[Biological effects and health risks of electromagnetic fields at levels classified by INCRIP ans admissible among occupationally exposed workers: a study of the Nofer Institute of Occupational Medicine, Lodz].  

PubMed

The aim of the study was to evaluate the effect of electromagnetic fields (EMF) on the workers' circulatory system, and to find out to what extent the EMF frequency, short-term (maximum values) and chronic (daily and lifetime doses) exposures influence the type of the observed disorders. The gathered data will help to evaluate whether hygiene standards that limit maximum admissible EMF values (e.g., ICNIRP standards) protect against adverse effects of exposure. The study covered workers employed in transformer and distribution stations, medium wave transmitting stations, radio-service and radio and TV multichannel broadcasting stations. In all the cases, exposure levels were considerably lower than those set as admissible according to the ICNIRP standards. Nevertheless changes in the circulatory system and a significant relationship between blood pressure and neurovegetative regulation disorders and exposure parameters were observed. The frequency of changes in the circulatory system was significantly dependent not only on the maximum EMF value, but also on its dose, which indicates that the hygiene standards for EMF cannot be limited only to short-term exposure maximum values, but they should be supplemented with dose-related standards. PMID:14669585

Bortkiewicz, Alicja; Gadzicka, Elzbieta; Zmy?lony, Marek

2003-01-01

169

NISTHB 150-11 Electromagnetic  

E-print Network

NISTHB 150-11 NVLAP Electromagnetic Compatibility and Telecommunications Bethany Hackett Bradley. #12;NISTHB 150-11 NVLAP Electromagnetic Compatibility and Telecommunications Bethany Hackett Bradley Programs Dennis Camell Electromagnetics Division Physical Measurement Laboratory http://dx.doi.org/10

170

Electromagnetic probes of the QGP  

E-print Network

We investigate the properties of the QCD matter across the deconfinement phase transition in the scope of the parton-hadron string dynamics (PHSD) transport approach. We present here in particular the results on the electromagnetic radiation, i.e. photon and dilepton production, in relativistic heavy-ion collisions. By comparing our calculations for the heavy-ion collisions to the available data, we determine the relative importance of the various production sources and address the possible origin of the observed strong elliptic flow $v_2$ of direct photons. We argue that the different centrality dependence of the hadronic and partonic sources for direct photon production in nucleus-nucleus collisions can be employed to shed some more light on the origin of the photon $v_2$ "puzzle". While the dilepton spectra at low invariant mass show in-medium effects like an enhancement from multiple baryonic resonance formation or a collisional broadening of the vector meson spectral functions, the dilepton yield at high invariant masses (above 1.1 GeV) is dominated by QGP contributions for central heavy-ion collisions at ultra-relativistic energies. This allows to have an independent view on the parton dynamics via their electromagnetic massive radiation.

E. L. Bratkovskaya; O. Linnyk; W. Cassing

2014-09-15

171

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

172

Electromagnetic Wave Dynamics in  

E-print Network

possibilities for strong localization of electromagnetic radiation in a dense and ultracold atomic gas sample the localization of light in ultracold samples of gas-phase Rb atoms has, until now, been focused on lightMesoscopic Electromagnetic Wave Dynamics in Ultracold Atomic Gases Robin Kaiser and Mark D. Havey

173

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.

174

Electromagnetic Analysis: Concrete Results  

Microsoft Academic Search

Abstract Although the possibility of attacking smart - cards by analyz - ing their electromagnetic power radiation repeatedly appears in research papers, all accessible references evade the essence of reporting conclusive experiments where actual cryptographic algorithms such as des or rsa were successfully attacked This work describes electromagnetic experiments conducted on three dif - ferent cmos chips, featuring di erent

Karine Gandolfi; Christophe Mourtel; Francis Olivier

2001-01-01

175

The Electromagnetic Spectrum  

NSDL National Science Digital Library

This is a lesson about the electromagnetic spectrum. Learners will read two pages of information about the electromagnetic spectrum and answer questions in an accompanying worksheet. This activity is from the Stanford Solar Center's All About the Sun: Sun and Stars activity guide for Grades 5-8 and can also accompany the Stanford Solar Center's Build Your Own Spectroscope activity.

176

SMILE Lab: Electromagnets  

NSDL National Science Digital Library

This site contains instructions for a fairly simple lab or demonstration using electromagnets. The electromagnets are made with nails, copper wire, and batteries. The lab includes a list of needed materials, the procedure that the students should follow, and a brief discussion of the physical concepts involved.

Johnson, Porter

2006-07-18

177

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

178

Mixed-level optical-system simulation incorporating component-level modeling of interface elements  

NASA Astrophysics Data System (ADS)

While system-level simulation can allow designers to assess optical system performance via measures such as signal waveforms, spectra, eye diagrams, and BER calculations, component-level modeling can provide a more accurate description of coupling into and out of individual devices, as well as their detailed signal propagation characteristics. In particular, the system-level simulation of interface components used in optical systems, including splitters, combiners, grating couplers, waveguides, spot-size converters, and lens assemblies, can benefit from more detailed component-level modeling. Depending upon the nature of the device and the scale of the problem, simulation of optical transmission through these components can be carried out using either electromagnetic device-level simulation, such as the beampropagation method, or ray-based approaches. In either case, system-level simulation can interface to such componentlevel modeling via a suitable exchange of optical signal data. This paper presents the use of a mixed-level simulation flow in which both electromagnetic device-level and ray-based tools are integrated with a system-level simulation environment in order to model the use of various interface components in optical systems for a range of purposes, including, for example, coupling to and from optical transmission media such as single- and multimode optical fiber. This approach enables case studies on the impact of physical and geometric component variations on system performance, and the sensitivity of system behavior to misalignment between components.

Mena, Pablo V.; Stone, Bryan; Heller, Evan; Herrmann, Dan; Ghillino, Enrico; Scarmozzino, Rob

2014-03-01

179

Electromagnetic interference in balanced converters .  

E-print Network

??In this dissertation, an investigation into reducing Electromagnetic Interference (EMI) through design is presented. Root generation mechanisms of Electromagnetic Interference are often neglected during the… (more)

Burford, Steven Trefor

2014-01-01

180

Lamb shift in nondegenerate energy level systems placed between two  

E-print Network

­degenerate energy levels, put in the electromagnetic environment provided by two infinite parallel conducting plates of the electromagnetic field. In free space, the ground state of the quantized electromagnetic field is the siege of quan­like atoms, the s­levels are the only ones dressed by the electromagnetic field quan­ tum fluctuations

Recanati, Catherine

181

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

182

I. What is electromagnetic radiation and the electromagnetic spectrum?  

E-print Network

i­1 I. What is electromagnetic radiation and the electromagnetic spectrum? What do light, X effects on matter. This "stuff" is called electromagnetic radiation, because it travels (radiates) and has electrical and magnetic effects. Electromagnetic radiation is the means for many of our interactions

Sitko, Michael L.

183

Classical Trajectories and Quantum Spectra  

NASA Technical Reports Server (NTRS)

A classical model of the Schrodinger's wave packet is considered. The problem of finding the energy levels corresponds to a classical manipulation game. It leads to an approximate but non-perturbative method of finding the eigenvalues, exploring the bifurcations of classical trajectories. The role of squeezing turns out decisive in the generation of the discrete spectra.

Mielnik, Bogdan; Reyes, Marco A.

1996-01-01

184

Microslots : scalable electromagnetic instrumentation  

E-print Network

This thesis explores spin manipulation, fabrication techniques and boundary conditions of electromagnetism to bridge the macroscopic and microscopic worlds of biology, chemistry and electronics. This work is centered around ...

Maguire, Yael G., 1975-

2004-01-01

185

The classical geometrization electromagnetism  

E-print Network

Following the line of the history, if by one side the electromagnetic theory was consolidated on the 19th century, the emergence of the special and the general relativity theories on the 20th century opened possibilities of further developments, with the search for the unification of the gravitation and the electromagnetism on a single unified theory. Some attempts to the geometrization of the electromagnetism emerged in this context, where these first models resided strictly on a classical basis. Posteriorly, they were followed by more complete and embracing quantum field theories. The present work reconsiders the classical viewpoint, with the purpose of showing that in a first order of approximation the electromagnetism constitutes a geometric structure aside other phenomena as gravitation. Even though being limited, the model is consistent and offers the possibility of an experimental test of validity.

C. A. Duarte

2015-02-11

186

Inverse problems in electromagnetics  

E-print Network

Two inverse problems in electromagnetics are investigated in this thesis. The first is the retrieval of the effective constitutive parameters of metamaterials from the measurement of the reflection and the transmission ...

Chen, Xudong, 1977-

2005-01-01

187

Electromagnetism in the Movies.  

ERIC Educational Resources Information Center

Describes how the authors used portions of popular movies to help students review concepts related to electromagnetism. Movies used and concepts covered in the review are listed, and a sample activity is described. (WRM)

Everitt, Lori R.; Patterson, Evelyn T.

1999-01-01

188

Purely electromagnetic spacetimes  

E-print Network

Electrovacuum solutions devoid of usual mass sources are classified in the case of one, two and three commuting Killing vectors. Three branches of solutions exist. Electromagnetically induced mass terms appear in some of them.

B. V. Ivanov

2007-12-15

189

An opening electromagnetic transducer  

NASA Astrophysics Data System (ADS)

Tubular solenoids have been widely used without any change since an electrical wire was discovered to create magnetic fields by Hans Christian Oersted in 1820 and thereby the wire was first coiled as a helix into a solenoid coil by William Sturgeon in 1823 and was improved by Joseph Henry in 1829 [see http://www.myetymology.com/encyclopedia/History_of_the_electricity.html; J. M. D. Coey, Magnetism and Magnetic Materials (Cambridge University Press, New York, 2010); and F. Winterberg, Plasma Phys. 8, 541553 (1996)]. A magnetic control method of C-shaped carrying-current wire is proposed, and thereby a new opening electromagnetic transducer evidently differing from the traditional tubular solenoid is created, capable of directly encircling and centering the acted objects in it, bringing about convenient and innovative electromagnetic energy conversion for electromagnetic heating, electromagnetic excitation, physical information capture, and electro-mechanical motion used in science research, industry, and even biomedical activities.

Sun, Yanhua; Kang, Yihua

2013-12-01

190

Ab initio calculations on the X (1)A(') and A (1)A(") states of HPO and Franck-Condon simulation of the single vibronic level emission spectra of HPO and DPO.  

PubMed

Minimum-energy geometries and relative electronic energies of the X (1)A(') and A (1)A(") states of HPO have been computed employing the coupled-cluster single-double plus perturbative triple excitations {RCCSD(T)} and/or complete-active-space self-consistent-field (CASSCF) multireference internally contracted configuration interaction (MRCI) methods with basis sets of up to the augmented correlation-consistent polarized-valence quintuple-zeta (aug-cc-pV5Z) quality. In addition, RCCSD(T)/aug-cc-pVQZ and CASSCF/MRCI/aug-cc-pVQZ potential energy functions, anharmonic vibrational wave functions, and energies involving all three vibrational modes for both electronic states of HPO and DPO, and Franck-Condon factors between the two electronic states, which allow for Duschinsky rotation and anharmonicity, were computed. Computed Franck-Condon factors were then used to simulate single vibronic level (SVL) emission spectra recently reported by Tackett and Clouthier [J. Chem. Phys. 117, 10604 (2002)]. Excellent agreement between the simulated and observed spectra was obtained for the A (1)A(")(1,0,0)-->X (1)A(') SVL emission of HPO and DPO, when the best estimated ab initio geometries of the two states, which include contributions from core correlation and extrapolation to the complete basis set limit, were used in the simulation, suggesting that the best estimated ab initio geometry of the A (1)A(") state of HPO, particularly the bond angle of 94.5 degrees , is more reliable than the available experimentally derived geometry. A discussion on the geometrical parameters derived from rotational constants obtained from the rotational analysis of a high-resolution spectrum and from Franck-Condon simulation of the vibrational structure of an electronic spectrum is given. PMID:18067355

Lee, Edmond P F; Mok, Daniel K W; Chau, Foo-Tim; Dyke, John M

2007-12-01

191

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

192

THERMAL RADIATION The type of electromagnetic radiation that is pertinentThe type of electromagnetic radiation that is pertinent  

E-print Network

THERMAL RADIATION The type of electromagnetic radiation that is pertinentThe type of electromagnetic radiation that is pertinent to heat transfer is the thermal radiation emitted as a result of the strength of these activities at the microscopic level, and the rate of thermal radiation emission increases

Kostic, Milivoje M.

193

Unresolved mossbauer hyperfine spectra  

NASA Technical Reports Server (NTRS)

Program analyzes unresolved Mossbauer hyperfine spectra resulting from existence of several local environments in dilute binary iron alloys. It has proven useful in studying effects of imputity atoms on iron Mossbauer spectra.

Schiess, J. R.; Singh, J. J.

1980-01-01

194

Toroidal dipolar excitation and macroscopic electromagnetic properties of metamaterials  

NASA Astrophysics Data System (ADS)

The toroidal dipole is a peculiar electromagnetic excitation that can not be presented in terms of standard electric and magnetic multipoles. A static toroidal dipole has been shown to lead to violation of parity in atomic spectra and many other unusual electromagnetic phenomena. The existence of electromagnetic resonances of toroidal nature was experimentally demonstrated only recently, first in the microwave metamaterials, and then at optical frequencies, where they could be important in spectroscopy analysis of a wide class of media with constituents of toroidal symmetry, such as complex organic molecules, fullerenes, bacteriophages, etc. Despite the experimental progress in studying toroidal resonances, no direct link has yet been established between microscopic toroidal excitations and macroscopic scattering characteristics of the medium. To address this essential gap in the electromagnetic theory, we have developed an analytical approach for calculating the transmissivity and reflectivity of thin slabs of materials that exhibit toroidal dipolar excitations.

Savinov, V.; Fedotov, V. A.; Zheludev, N. I.

2014-05-01

195

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.

196

Electromagnetic modeling of plasmonic nanostructures  

NASA Astrophysics Data System (ADS)

In this thesis, plasmonic properties of metal nanostructures are investigated by electromagnetic simulations using the finite difference time domain (FDTD) method. Chapter 1 covers the background knowledge required to read this thesis. It talks about the fundamentals of the FDTD method, the physics of plasmonics and a brief description of photocatalysis. In chapter 2, we perform optimization of plasmonic nanoparticle geometries. An iterative optimization algorithm is used to determine the configuration of the nanoparticles that gives the maximum electric field intensity at the center of the cluster. We observe that the optimum configurations of these clusters have mirror symmetry about the axis of planewave propagation, but are otherwise non-symmetric and non-intuitive. The maximum field intensity is found to increase monotonically with the number nanoparticles in the cluster, producing intensities that are 2500 times larger than the incident electromagnetic field. In chapter 3, evaporated thin films are imaged with high resolution transmission electron microscopy (HRTEM), to reveal the structure of the semicontinuous metal island film with sub-nm resolution. The electric field distributions and the absorption spectra of these semicontinuous island film geometries are calculated using the finite difference time domain (FDTD) method and compared with the experimentally measured absorption spectra. In addition to that, we calculate the SERS enhancement factors and photocatalytic enhancement factors of these films. We also study the effect of annealing on these films, which results in a large reduction in electric field strength due to increased nanoparticle spacing. In chapter 4, we study the effects of surrounding nanoparticles on a plasmonic hot spot. From our simulations, we show that the surrounding film contributes significantly to the electric field intensity at the hot spot by focusing energy to it. Widening of the gap size causes a decrease in the intensity at the hot spot. However, these island-like nanoparticle hot spots are shown to be robust to gap size than nanoparticle dimer geometries, studied previously. In fact, the main factor in determining the hot spot intensity is the focusing effect of the surrounding nano-islands. In chapter 5, we demonstrate plasmon-enhanced photocatalytic water splitting, and reduction of CO2 with H2O to form hydrocarbon fuels. Under visible illumination, we observe enhancements of up to 66X in the photocatalytic splitting of water in TiO2 with the addition of Au nanoparticles. We also perform a systematic study of the mechanisms of Au nanoparticle/TiO 2-catalyzed photoreduction of CO2 and water vapor over a wide range of wavelengths. In this case, under visible light illumination, we observe a 24-fold enhancement in the photocatalytic activity due to the intense local electromagnetic fields created by the surface plasmons of the Au nanoparticles. Above the plasmon resonance, under ultraviolet radiation we observe a reduction in the photocatalytic activity. Electromagnetic simulations indicate that the improvement of photocatalytic activity in the visible range is caused by the local electric field enhancement near the TiO2 surface, rather than by the direct transfer of charge between the two materials. In chapter 6, I will talk about a method for fabricating arrays of plasmonic nanoparticles with separations on the order of 1nm using an angle evaporation technique. High resolution transmission electron microscopy (HRTEM) is used to resolve the small separations achieved between nanoparticles fabricated on thin SiN membranes. These nearly touching metal nanoparticles produce extremely high electric field intensities when irradiated with laser light. We perform surface enhanced Raman spectroscopy (SERS) a non-resonant dye molecule (p-ATP) deposited on the nanoparticle arrays using confocal micro-Raman spectroscopy. Our results show significant enhancement when the incident laser is polarized parallel to the axis of the nanoparticle pairs, whereas no enhancement is observed for the p

Pavaskar, Prathamesh

197

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

198

Electromagnetic properties of viscous charged fluids  

E-print Network

We provide a general theoretical framework to describe the electromagnetic properties of viscous charged fluids, consisting for example of electrons in certain solids or plasmas. We confirm that finite viscosity leads to multiple modes of evanescent electromagnetic waves at a given frequency, one of which is characterized by a negative index of refraction, as previously discussed in a simplified model by one of the authors. In particular we explain how optical spectroscopy can be used to probe the viscosity. We concentrate on the impact of this on the coefficients of refraction and reflection at the sample-vacuum interface. Analytical expressions are obtained relating the viscosity parameter to the reflection and transmission coefficients of light. We demonstrate that finite viscosity has the effect to decrease the reflectivity of a metallic surface, while the electromagnetic field penetrates more deeply. While on a phenomenological level there are similarities to the anomalous skin effect, the model presente...

Forcella, Davide; Valentinis, Davide; van der Marel, Dirk

2014-01-01

199

How Astronomers Use Spectra to Learn About the Sun and Other Stars  

NSDL National Science Digital Library

This is a booklet about spectra and their usefulness to astronomers. Learners will read about the electromagnetic spectrum, how atomic physics is used to obtain information out of stellar spectra, and how the Doppler effect is used to measure stellar motions. An activity at the end allows learners to analyze and identify several emission lines in the spectrum of the Sun.

200

Electromagnetic compatibility management for fast diagnostic design  

NASA Astrophysics Data System (ADS)

This article presents an overview of electromagnetic compatibility (EMC) management for fast diagnostic design. We will present and detail the classical approach in EMC. This approach can be successfully applied for installations where a single engineering entity has the authority to prescribe and enforce a certain compatibility level. Most of the time, strict application of generic standards is required for fast diagnostics. Nethertheless, the pulse perturbation must be synchronized to the fast diagnostic operation. Some "traditional" techniques, such as star-earthing and bonding cable screens at one end, have been shown to be inadequate for fast diagnostic design. Our laser facility, the LIL, will be able to focus up to 60 kJ into a volume of less than 1 mm3. We have to evaluate the electromagnetic pulse (EMP) where diagnostics, cables, and oscilloscopes will be installed. We performed electromagnetic measurements inside and outside the OMEGA target chamber. The electromagnetic pulse generated by the target chamber contains very high frequency components above 1 GHz. The electric field is around a few kV/m outside and goes up to 20 kV/m inside the target. We designed a specific electromagnetic probe for pulse measurement with a rise time down to 100 ps. An ultrashort rise time EMP bench test was built to test apparatus before installation around a target chamber. It produces an electric field higher than 5 kV/m with a rise time under 100 ps.

Raimbourg, J.

2004-10-01

201

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

202

Aircraft electromagnetic compatibility  

NASA Technical Reports Server (NTRS)

Illustrated are aircraft architecture, electromagnetic interference environments, electromagnetic compatibility protection techniques, program specifications, tasks, and verification and validation procedures. The environment of 400 Hz power, electrical transients, and radio frequency fields are portrayed and related to thresholds of avionics electronics. Five layers of protection for avionics are defined. Recognition is given to some present day electromagnetic compatibility weaknesses and issues which serve to reemphasize the importance of EMC verification of equipment and parts, and their ultimate EMC validation on the aircraft. Proven standards of grounding, bonding, shielding, wiring, and packaging are laid out to help provide a foundation for a comprehensive approach to successful future aircraft design and an understanding of cost effective EMC in an aircraft setting.

Clarke, Clifton A.; Larsen, William E.

1987-01-01

203

Electromagnetic particle simulation codes  

NASA Technical Reports Server (NTRS)

Electromagnetic particle simulations solve the full set of Maxwell's equations. They thus include the effects of self-consistent electric and magnetic fields, magnetic induction, and electromagnetic radiation. The algorithms for an electromagnetic code which works directly with the electric and magnetic fields are described. The fields and current are separated into transverse and longitudinal components. The transverse E and B fields are integrated in time using a leapfrog scheme applied to the Fourier components. The particle pushing is performed via the relativistic Lorentz force equation for the particle momentum. As an example, simulation results are presented for the electron cyclotron maser instability which illustrate the importance of relativistic effects on the wave-particle resonance condition and on wave dispersion.

Pritchett, P. L.

1985-01-01

204

A class of non-null toroidal electromagnetic fields and its relation to the model of electromagnetic knots  

NASA Astrophysics Data System (ADS)

An electromagnetic knot is an electromagnetic field in vacuum in which the magnetic lines and the electric lines coincide with the level curves of a pair of complex scalar fields ? and ? (see equations (A.1), (A.2)). When electromagnetism is expressed in terms of electromagnetic knots, it includes mechanisms for the topological quantization of the electromagnetic helicity, the electric charge, the electromagnetic energy inside a cavity and the magnetic flux through a superconducting ring. In the case of electromagnetic helicity, its topological quantization depends on the linking number of the field lines, both electric and magnetic. Consequently, to find solutions of the electromagnetic knot equations with nontrivial topology of the field lines has important physical consequences. We study a new class of solutions of Maxwell?s equations in vacuum Arrayás and Trueba (2011 arXiv:1106.1122) obtained from complex scalar fields that can be interpreted as maps {{S}3}\\to {{S}2}, in which the topology of the field lines is that of the whole torus-knot set. Thus this class of solutions is built as electromagnetic knots at initial time. We study some properties of those fields and consider if detection based on the energy and momentum observables is possible.

Arrayás, Manuel; Trueba, José L.

2015-01-01

205

Concurrent Circuit-Level/System-Level Optimization of a 24 GHz Mixer for Automotive Applications Using a Hybrid  

E-print Network

, mixer, hybrid/concurrent optimization, statistical tools, electromagnetic design. I. INTRODUCTIONConcurrent Circuit-Level/System-Level Optimization of a 24 GHz Mixer for Automotive Applications Using a Hybrid Electromagnetic/Statistical Technique Francesco Placentino', Daniela Staiculescu2, Symeon

Tentzeris, Manos

206

Electromagnetic propulsion test facility  

NASA Technical Reports Server (NTRS)

A test facility for the exploration of electromagnetic propulsion concept is described. The facility is designed to accommodate electromagnetic rail accelerators of various lengths (1 to 10 meters) and to provide accelerating energies of up to 240 kiloJoules. This accelerating energy is supplied as a current pulse of hundreds of kiloAmps lasting as long as 1 millisecond. The design, installation, and operating characteristics of the pulsed energy system are discussed. The test chamber and its operation at pressures down to 1300 Pascals (10 mm of mercury) are described. Some aspects of safety (interlocking, personnel protection, and operating procedures) are included.

Gooder, S. T.

1984-01-01

207

Improved Electromagnetic Brake  

NASA Technical Reports Server (NTRS)

A proposed design for an electromagnetic brake would increase the reliability while reducing the number of parts and the weight, relative to a prior commercially available electromagnetic brake. The reductions of weight and the number of parts could also lead to a reduction of cost. A description of the commercial brake is prerequisite to a description of the proposed electromagnetic brake. The commercial brake (see upper part of figure) includes (1) a permanent magnet and an electromagnet coil on a stator and (2) a rotor that includes a steel contact plate mounted, with tension spring loading, on an aluminum hub. The stator is mounted securely on a stationary object, which would ordinarily be the housing of a gear drive or a motor. The rotor is mounted on the shaft of the gear drive or motor. The commercial brake nominally operates in a fail-safe (in the sense of normally braking) mode: In the absence of current in the electromagnet coil, the permanent magnet pulls the contact plate, against the spring tension, into contact with the stator. To release the brake, one excites the electromagnet with a current of the magnitude and polarity chosen to cancel the magnetic flux of the permanent magnet, thereby enabling the spring tension to pull the contact plate out of contact with the stator. The fail-safe operation of the commercial brake depends on careful mounting of the rotor in relation to the stator. The rotor/stator gap must be set with a tolerance between 10 and 15 mils (between about 0.25 and about 0.38 mm). If the gap or the contact pad is thicker than the maximum allowable value, then the permanent magnetic field will not be strong enough to pull the steel plate across the gap. (For this reason, any contact pad between the contact plate and the stator must also be correspondingly thin.) If the gap exceeds the maximum allowable value because of shaft end play, it becomes impossible to set the brake by turning off the electromagnet current. Although it may still be possible to set the brake by applying an electromagnet current to aid the permanent magnetic field instead of canceling it, this action can mask an out-of-tolerance condition in the brake and it does not restore the fail-safe function of setting the brake when current is lost.

Martin, Toby B.

2004-01-01

208

Electromagnetic power absorber  

NASA Technical Reports Server (NTRS)

A structure is presented with a surface portion of dielectric material which passes electromagnetic radiation and with a portion below the surface which includes material that absorbs the radiation, the face of the structure being formed with numerous steep ridges. The steepness of the dielectric material results in a high proportion of the electromagnetic energy passing through the surface for absorption by the absorbing material under the surface. A backing of aluminum or other highly heat-conductive and reflective material lies under the face and has very steep protuberances supporting the absorbing and dielectric materials.

Iwasaki, R. S. (inventor)

1979-01-01

209

3. ELECTROMAGNETIC COMPATIBILITY Abstract --The electromagnetic interference between the  

E-print Network

3. ELECTROMAGNETIC COMPATIBILITY Abstract -- The electromagnetic interference between the electromagnetic fields in 3D, assuming that the field is computed outside a sphere of radius r that contains impedance of the considered environment. - and are the magnetic and electric multipoles, respectively

Paris-Sud XI, Université de

210

Canceling Electromagnetic Interference During Tests  

NASA Technical Reports Server (NTRS)

Old technique solves modern problem. Simple amplitude-and-phase-cancellation technique removes strong electromagnetic interference from received test signal, enabling recovery of relatively weak signal from device under test. Useful in outdoor tests of devices for electromagnetic compatibility.

Robinson, Paul A., Jr.; Edmonds, Larry D.

1988-01-01

211

8.07 Electromagnetism II, Fall 2005  

E-print Network

This course is the second in a series on Electromagnetism beginning with Electromagnetism I (8.02 or 8.022). It is a survey of basic electromagnetic phenomena: electrostatics; magnetostatics; electromagnetic properties of ...

Bertschinger, Edmund

212

Electromagnetic Radiation REFERENCE: Remote Sensing of  

E-print Network

1 CHAPTER 2: Electromagnetic Radiation Principles REFERENCE: Remote Sensing of the Environment John;2 Electromagnetic Energy Interactions Energy recorded by remote sensing systems undergoes fundamental interactions, creating convectional currents in the atmosphere. c) Electromagnetic energy in the form of electromagnetic

Gilbes, Fernando

213

Electromagnetically Induced Flows Michiel de Reus  

E-print Network

Electromagnetically Induced Flows in Water Michiel de Reus 8 maart 2013 () Electromagnetically Conclusion and future research () Electromagnetically Induced Flows 2 / 56 #12;1 Introduction 2 Maxwell Navier Stokes equations 5 Simulations 6 Conclusion and future research () Electromagnetically Induced

Vuik, Kees

214

Crack spectra analysis  

SciTech Connect

Crack spectra derived from velocity data have been shown to exhibit systematics which reflect microstructural and textural differences between samples (Warren and Tiernan, 1980). Further research into both properties and information content of crack spectra have yielded the following: Spectral features are reproducible even at low pressures; certain observed spectral features may correspond to non-in-situ crack populations created during sample retrieval; the functional form of a crack spectra may be diagnostic of the sample's grain texture; hysteresis is observed in crack spectra between up and down pressure runs - it may be due to friction between the faces of closed crack populations.

Tiernan, M.

1980-09-01

215

Electromagnetic fields and health outcomes.  

PubMed

Over the past two decades, there has been increasing interest in the biological effects and possible health outcomes of weak, low-frequency electric and magnetic fields. Epidemiological studies on magnetic fields and cancer, reproduction and neurobehavioural reactions have been presented. More recently, neurological, degenerative and heart diseases have also been reported to be related to such electromagnetic fields. Furthermore, the increased use of mobile phones worldwide has focussed interest on the possible effects of radiofrequency fields of higher frequencies. In this paper, a summary is given on electromagnetic fields and health outcomes and what policy is appropriate--"no restriction to exposure", "prudent avoidance" or "expensive interventions"? The results of research studies have not been unambiguous; studies indicating these fields as being a health hazard have been published and so were studies indicating no risk at all. In "positive" studies, different types of effects have been reported despite the use of the same study design, e.g., in epidemiological cancer studies. There are uncertainties as to exposure characteristics, e.g., magnetic field frequency and exposure intermittence, and not much is known about possible confounding or effect-modifying factors. The few animal cancer studies reported have not given much help in risk assessment; and in spite of a large number of experimental cell studies, no plausible and understandable mechanisms have been presented by which a carcinogenic effect could be explained. Exposure to electromagnetic fields occurs everywhere: in the home, at work, in school, etc. Wherever there are electric wires, electric motors and electronic equipment, electromagnetic fields are created. This is one of the reasons why exposure assessment is difficult. For epidemiologists, the problems is not on the effect side as registers of diseases exist in many countries today. The problem is that epidemiologists do not know the relevant exposure characteristics to be used in their studies. In international guidelines, limits for restrictions of field exposure are several orders of magnitude above what can be measured from overhead power lines and found in "electrical" occupations. These guidelines emphasize that the state of scientific knowledge today does not warrant limiting exposure levels for the public and the work force, and that further data are required to confirm whether health hazards are present. In some countries, however, the "principle of caution" or "prudent avoidance" has been adopted; meaning the low-cost avoidance of unnecessary exposure as long as there is scientific uncertainty about its health effects. PMID:11603131

Knave, B

2001-09-01

216

Electromagnetic probes of the QGP  

E-print Network

We investigate the properties of the QCD matter across the deconfinement phase transition in the scope of the parton-hadron string dynamics (PHSD) transport approach. We present here in particular the results on the electromagnetic radiation, i.e. photon and dilepton production, in relativistic heavy-ion collisions. By comparing our calculations for the heavy-ion collisions to the available data, we determine the relative importance of the various production sources and address the possible origin of the observed strong elliptic flow $v_2$ of direct photons. We argue that the different centrality dependence of the hadronic and partonic sources for direct photon production in nucleus-nucleus collisions can be employed to shed some more light on the origin of the photon $v_2$ "puzzle". While the dilepton spectra at low invariant mass show in-medium effects like an enhancement from multiple baryonic resonance formation or a collisional broadening of the vector meson spectral functions, the dilepton yield at high...

Bratkovskaya, E L; Cassing, W

2014-01-01

217

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

218

Simple Superconducting "Permanent" Electromagnet  

NASA Technical Reports Server (NTRS)

Proposed short tube of high-temperature-superconducting material like YBa2Cu3O7 acts as strong electromagnet that flows as long as magnetic field remains below critical value and temperature of cylinder maintained sufficiently below superconducting-transition temperature. Design exploits maximally anisotropy of high-temperature-superconducting material.

Israelson, Ulf E.; Strayer, Donald M.

1992-01-01

219

Electromagnetic ultrasonic transducers  

Microsoft Academic Search

Direct electromagnetic generation is a relatively recent addition to the list of techniques available for the generation of ultrasonic waves for nondestructive evaluation purposes. The history and physics of the generation technique will be discussed. In addition, transducer designs for the generation of various types of sound waves (longitudinal, shear and surface) will be presented. In particular, surface wave transducer

T. J. Moran

1979-01-01

220

Electromagnetism and Gravitation  

E-print Network

The classical concept of "mass density" is not fundamental to the quantum theory of matter. Therefore, mass density cannot be the source of gravitation. Here, we treat electromagnetic energy, momentum, and stress as its source. The resulting theory predicts that the gravitational potential near any charged elementary particle is many orders of magnitude greater than the Newtonian value.

Kenneth Dalton

1995-12-12

221

Electromagnetic pulsar spindown  

E-print Network

We evaluate the result of the recent pioneering numerical simulations in Spitkovsky~2006 on the spindown of an oblique relativistic magnetic dipole rotator. Our discussion is based on our experience from two idealized cases, that of an aligned dipole rotator, and that of an oblique split-monopole rotator. We conclude that the issue of electromagnetic pulsar spindown may not have been resolved yet.

I. Contopoulos

2007-01-10

222

Electromagnetic brain mapping  

Microsoft Academic Search

There has been tremendous advances in our ability to produce images of human brain function. Applications of functional brain imaging extend from improving our understanding of the basic mechanisms of cognitive processes to better characterization of pathologies that impair normal function. Magnetoencephalography (MEG) and electroencephalography (EEG) (MEG\\/EEG) localize neural electrical activity using noninvasive measurements of external electromagnetic signals. Among the

S. Baillet; J. C. Mosher; R. M. Leahy

2001-01-01

223

Equivalence principles and electromagnetism  

NASA Technical Reports Server (NTRS)

The implications of the weak equivalence principles are investigated in detail for electromagnetic systems in a general framework. In particular, it is shown that the universality of free-fall trajectories (Galileo weak equivalence principle) does not imply the validity of the Einstein equivalence principle. However, the Galileo principle plus the universality of free-fall rotation states does imply the Einstein principle.

Ni, W.-T.

1977-01-01

224

Nucleon electromagnetic form factors  

SciTech Connect

A review of data on the nucleon electromagnetic form factors in the space-like region is presented. Recent results from experiments using polarized beams and polarized targets or nucleon recoil polarimeters have yielded a significant improvement on the precision of the data obtained with the traditional Rosenbluth separation. Future plans for extended measurements are outlined.

Kees de Jager

2000-01-01

225

Noncontact Electromagnetic Vibration Source  

NASA Technical Reports Server (NTRS)

Metal aircraft skins scanned rapidly in vibration tests. Relatively simple combination of permanent magnets and electromagnet serves as noncontact vibration source for nondestructive testing of metal aircraft skins. In test, source excites vibrations, and vibration waveforms measured, then analyzed for changes in resonances signifying cracks and other flaws.

Namkung, Min; Fulton, James P.; Wincheski, Buzz A.

1994-01-01

226

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

227

Spectroscopy Interaction of electromagnetic radiation  

E-print Network

Spectroscopy 691 Interaction of electromagnetic radiation with atoms or molecules #12;Bacteriorhodopsin: a light-driven proton pump 486 #12;Electromagnetic Radiation 692 harmonic wave (Maxwell): y;Spectroscopy 691 Interaction of electromagnetic radiation with atoms or molecules two processes: emission

Gerwert, Klaus

228

Electromagnetic environment of RFID systems  

Microsoft Academic Search

In this paper, the influence of the electromagnetic environment on RFID (radio frequency identification) systems is studied. By electromagnetic environment, we consider the electromagnetic waves interference on a RFID system performance produced by applications located nearby. In particular, we analyze the effects of using a GSM mobile phone near an UHF-868 MHz RFID system. For the tested configurations, the results

Delia Arnaud-Cormos; Thierry Letertre; Antoine Diet; Alain Azoulay

2007-01-01

229

Optical properties of excitons in quantum dots: diffraction of an electromagnetic plane wave by a spherical quantum dot  

Microsoft Academic Search

We show how to compute the optical spectra resulting from the scattering of a plane electromagnetic wave on a quantum dot (QD) in the region of the excitonic resonances. The method uses the microscopic calculation of quantum dot eigenfunctions and the macroscopic Stahl's density matrix approach to compute the electromagnetic field within and outside the QD, taking into account the

L. Silvestri; F. Bassani; G. Czajkowski

2000-01-01

230

Computational Electronics and Electromagnetics  

SciTech Connect

The Computational Electronics and Electromagnetics thrust area is a focal point for computer modeling activities in electronics and electromagnetics in the Electronics Engineering Department of Lawrence Livermore National Laboratory (LLNL). Traditionally, they have focused their efforts in technical areas of importance to existing and developing LLNL programs, and this continues to form the basis for much of their research. A relatively new and increasingly important emphasis for the thrust area is the formation of partnerships with industry and the application of their simulation technology and expertise to the solution of problems faced by industry. The activities of the thrust area fall into three broad categories: (1) the development of theoretical and computational models of electronic and electromagnetic phenomena, (2) the development of useful and robust software tools based on these models, and (3) the application of these tools to programmatic and industrial problems. In FY-92, they worked on projects in all of the areas outlined above. The object of their work on numerical electromagnetic algorithms continues to be the improvement of time-domain algorithms for electromagnetic simulation on unstructured conforming grids. The thrust area is also investigating various technologies for conforming-grid mesh generation to simplify the application of their advanced field solvers to design problems involving complicated geometries. They are developing a major code suite based on the three-dimensional (3-D), conforming-grid, time-domain code DSI3D. They continue to maintain and distribute the 3-D, finite-difference time-domain (FDTD) code TSAR, which is installed at several dozen university, government, and industry sites.

DeFord, J.F.

1993-03-01

231

Deduction of the chemical state and the electronic structure of Nd2Fe14B compound from X-ray photoelectron spectroscopy core-level and valence-band spectra  

NASA Astrophysics Data System (ADS)

Characterization of chemical state and electronic structure of the technologically important Nd2Fe14B compound is attractive for understanding the physical nature of its excellent magnetic properties. X-ray photoelectron spectroscopy (XPS) study of such rare-earth compound is important and also challenging due to the easy oxidation of surface and small photoelectron cross-sections of rare-earth 4f electrons and B 2p electrons, etc. Here, we reported an investigation based on XPS spectra of Nd2Fe14B compound as a function of Ar ion sputtering time. The chemical state of Fe and that of B in Nd2Fe14B compound can be clearly determined to be 0 and -3, respectively. The Nd in Nd2Fe14B compound is found to have the chemical state of close to +3 instead of +3 as compared with the Nd in Nd2O3. In addition, by comparing the valence-band spectrum of Nd2Fe14B compound to that of the pure Fe, the contributions from Nd, Fe, and B to the valence-band structure of Nd2Fe14B compound is made more clear. The B 2p states and B 2s states are identified to be at ˜11.2 eV and ˜24.6 eV, respectively, which is reported for the first time. The contribution from Nd 4f states can be identified both in XPS core-level spectrum and XPS valence-band spectrum. Although Nd 4f states partially hybridize with Fe 3d states, Nd 4f states are mainly localized in Nd2Fe14B compound.

Wang, Jing; Liang, Le; Zhang, Lanting; Sun, Limin; Hirano, Shinichi

2014-10-01

232

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

233

Optical Spectra of Supernovae  

Microsoft Academic Search

The temporal evolution of the optical spectra of various types of supernovae (SNe) is illustrated, in part to aid observers classifying supernova candidates. Type II SNe are defined by the presence of hydrogen, and they exhibit a very wide variety of photometric and spectroscopic properties. Among hydrogen-deficient SNe (Type I), three subclasses are now known: those whose early-time spectra show

Alexei V. Filippenko

1997-01-01

234

Electromagnetic Environment of Grounding Systems  

NASA Astrophysics Data System (ADS)

Electromagnetic compatibility (EMC) and lightning protection studies in large installations require knowledge of spatial and temporal distribution of electromagnetic fields in case of lightning and power system faults. A new hybrid method for modeling electromagnetic environment of grounding systems is developed in this work. The electromagnetic fields in the surrounding soil are determined from the previously calculated current distribution using dipoles theory with analytical formulas. The model can be used to predict the EM environment of grounding systems because it can calculate electromagnetic fields in any points of interest.

Lefouili, M.; Hafsaoui, I.; Kerroum, K.; Drissi, K. El Khamlichi

235

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

236

Magnetism and Electromagnetism  

NSDL National Science Digital Library

All About Circuits is a website that âÂÂprovides a series of online textbooks covering electricity and electronics.â Written by Tony R. Kuphaldt, the textbooks available here are wonderful resources for students, teachers, and anyone who is interested in learning more about electronics. This specific section, Magnetism and Electromagnetism, is the fourteenth chapter in Volume I â Direct Current. A few of the topics covered in this chapter include: Permanent magnets; Electromagnetic induction; and Mutual inductance. Diagrams and detailed descriptions of concepts are included throughout the chapter to provide users with a comprehensive lesson. Visitors to the site are also encouraged to discuss concepts and topics using the All About Circuits discussion forums (registration with the site is required to post materials).

Kuphaldt, Tony R.

2008-07-07

237

Environmental and space electromagnetics  

NASA Astrophysics Data System (ADS)

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 phenomena and EHD. Also discussed are the characteristics of winter lightning strokes observed with video camera systems, polar VLF emissions observed by ISIS satellites, ray focusing of whistler-mode waves in a magnetoplasma, radio sky mapping from satellites at VLFs, and MW observations of the sun during the 22nd solar activity cycle.

Kikuchi, Hiroshi

238

SAR-ocean wave inversion using image cross spectra  

Microsoft Academic Search

Image cross-spectra obtained by combining pairs of single look SAR images are utilized in an inversion scheme for extracting the underlying ocean wave spectrum. The reasons for proposing the use of image cross-spectra instead of standard multilook spectra are twofold. First, the image cross-spectra are shown to significantly reduce the speckle noise level while preserving the spectral shape. Second, the

Geir Engen; Harald Johnsen

1995-01-01

239

Faraday's Electromagnetic Lab  

NSDL National Science Digital Library

Play with a bar magnet and coils to learn about Faraday's law. Move a bar magnet near one or two coils to make a light bulb glow. View the magnetic field lines. A meter shows the direction and magnitude of the current. View the magnetic field lines or use a meter to show the direction and magnitude of the current. You can also play with electromagnets, generators and transformers!

Simulations, Phet I.; Dubson, Michael; Malley, Chris; Perkins, Kathy; Wieman, Carl; Harlow, Danielle

2005-04-01

240

The KLOE electromagnetic calorimeter  

Microsoft Academic Search

The KLOE calorimeter is a fine lead-scintillating fiber sampling calorimeter. We describe in the following the calibration procedures and the calorimeter performances obtained after 3 years of data taking. We get an energy resolution for electromagnetic showers of 5.4%\\/E(GeV) and a time resolution of 56 ps\\/E(GeV). We also present a measurement of efficiency for low-energy photons.

M. Adinolfi; F. Ambrosino; A. Antonelli; M. Antonelli; F. Anulli; G. Barbiellini; G. Bencivenni; S. Bertolucci; C. Bini; C. Bloise; V. Bocci; F. Bossi; P. Branchini; G. Cabibbo; R. Caloi; P. Campana; M. Casarsa; G. Cataldi; F. Ceradini; F. Cervelli; P. Ciambrone; E. De Lucia; P. De Simone; G. De Zorzi; S. Dell'Agnello; A. Denig; A. di Domenico; C. di Donato; S. Di Falco; A. Doria; O. Erriquez; A. Farilla; A. Ferrari; M. L. Ferrer; G. Finocchiaro; C. Forti; A. Franceschi; P. Franzini; M. L. Gao; C. Gatti; P. Gauzzi; A. Giannasi; S. Giovannella; E. Graziani; H. G. Han; S. W. Han; X. Huang; M. Incagli; L. Ingrosso; L. Keeble; W. Kim; C. Kuo; G. Lanfranchi; J. Lee-Franzini; T. Lomtadze; C. S. Mao; M. Martemianov; W. Mei; R. Messi; S. Miscetti; S. Moccia; M. Moulson; S. Müller; F. Murtas; L. Pacciani; M. Palomba; M. Palutan; E. Pasqualucci; L. Passalacqua; A. Passeri; D. Picca; G. Pirozzi; L. Pontecorvo; M. Primavera; P. Santangelo; E. Santovetti; G. Saracino; R. D. Schamberger; B. Sciascia; F. Scuri; I. Sfiligoi; P. Silano; T. Spadaro; E. Spiriti; L. Tortora; P. Valente; B. Valeriani; G. Venanzoni; A. Ventura; S. Wölfle; Y. Wu; Y. G. Xie; P. F. Zema; C. D. Zhang; J. Q. Zhang; P. P. Zhao

2002-01-01

241

Electromagnetic detection of axions  

E-print Network

Photon-to-axion conversions in the static electromagnetic fields are reconsidered in detail by using the Feynman diagram techniques. The differential cross sections are presented for the conversions in the presence of the electric field of the flat condenser as well as in the magnetic field of the solenoid. Based on our results a laboratory experiment for the production and the detection of the axions is described. This experiment will exploit the axion decay constant as well as the axion mass.

Hoang Ngoc Long; Dang Van Soa; Tuan A. Tran

1995-07-24

242

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.

Fanning, Alan W. (San Jose, CA); Gonzales, Aaron A. (San Jose, CA); Patel, Mahadeo R. (San Jose, CA); Olich, Eugene E. (Aptos, CA)

1994-01-01

243

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.

Fanning, Alan W. (San Jose, CA); Gonzales, Aaron A. (San Jose, CA); Patel, Mahadeo R. (San Jose, CA); Olich, Eugene E. (Aptos, CA)

1996-01-01

244

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

245

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

246

Quaternion Gravi-Electromagnetism  

E-print Network

Defining the generalized charge, potential, current and generalized fields as complex quantities where real and imaginary parts represent gravitation and electromagnetism respectively, corresponding field equation, equation of motion and other quantum equations are derived in manifestly covariant manner. It has been shown that the field equations are invariant under Lorentz as well as duality transformations. It has been shown that the quaternionic formulation presented here remains invariant under quaternion transformations.

A. S. Rawat; O. P. S. Negi

2011-07-05

247

Gravitation and Electromagnetism  

E-print Network

The realms of gravitation, belonging to Classical Physics, and Electromagnetism, belonging to the Theory of the Electron and Quantum Mechanics have remained apart as two separate pillars, inspite of a century of effort by Physicists to reconcile them. In this paper it is argued that if we extend ideas of Classical spacetime to include in addition to non integrability non commutavity also, then such a reconcilation is possible.

B. G. Sidharth

2001-06-16

248

Fractional Electromagnetic Waves  

E-print Network

In the present work we consider the electromagnetic wave equation in terms of the fractional derivative of the Caputo type. The order of the derivative being considered is 0 <\\gamma<1. A new parameter \\sigma, is introduced which characterizes the existence of the fractional components in the system. We analyze the fractional derivative with respect to time and space, for \\gamma = 1 and \\gamma = 1/2 cases.

J. F. Gómez; J. J. Rosales; J. J. Bernal; V. I. Tkach; M. Guía

2011-08-31

249

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

250

Theory of electromagnetic fluctuations for magnetized multi-species plasmas  

SciTech Connect

Analysis of electromagnetic fluctuations in plasma provides relevant information about the plasma state and its macroscopic properties. In particular, the solar wind persistently sustains a small but detectable level of magnetic fluctuation power even near thermal equilibrium. These fluctuations may be related to spontaneous electromagnetic fluctuations arising from the discreteness of charged particles. Here, we derive general expressions for the plasma fluctuations in a multi-species plasma following arbitrary distribution functions. This formalism, which generalizes and includes previous works on the subject, is then applied to the generation of electromagnetic fluctuations propagating along a background magnetic field in a plasma of two proton populations described by drifting bi-Maxwellians.

Navarro, Roberto E., E-mail: roberto.navarro@ug.uchile.cl; Muñoz, Víctor [Departamento de Física, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago (Chile); Araneda, Jaime [Departamento de Física, Universidad de Concepción, Concepción 4070386 (Chile); Moya, Pablo S. [NASA Goddard Space Flight Center, Heliophysics Science Division, Geospace Physics Laboratory, Mail Code 673, Greenbelt, Maryland 20771 (United States); Department of Physics, Catholic University of America, Washington, D. C. 20064 (United States); Viñas, Adolfo F. [NASA Goddard Space Flight Center, Heliophysics Science Division, Geospace Physics Laboratory, Mail Code 673, Greenbelt, Maryland 20771 (United States); Valdivia, Juan A. [Departamento de Física, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago (Chile); Centro de Estudios Interdisciplinarios Básicos y Aplicados en Complejidad, CEIBA complejidad, Bogotá (Colombia)

2014-09-15

251

Gravito-electromagnetic analogies  

NASA Astrophysics Data System (ADS)

We reexamine and further develop different gravito-electromagnetic (GEM) analogies found in the literature, and clarify the connection between them. Special emphasis is placed in two exact physical analogies: the analogy based on inertial fields from the so-called "1+3 formalism", and the analogy based on tidal tensors. Both are reformulated, extended and generalized. We write in both formalisms the Maxwell and the full exact Einstein field equations with sources, plus the algebraic Bianchi identities, which are cast as the source-free equations for the gravitational field. New results within each approach are unveiled. The well known analogy between linearized gravity and electromagnetism in Lorentz frames is obtained as a limiting case of the exact ones. The formal analogies between the Maxwell and Weyl tensors are also discussed, and, together with insight from the other approaches, used to physically interpret gravitational radiation. The precise conditions under which a similarity between gravity and electromagnetism occurs are discussed, and we conclude by summarizing the main outcome of each approach.

Costa, L. Filipe O.; Natário, José

2014-10-01

252

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

253

Electromagnetic properties of viscous charged fluids  

E-print Network

We provide a general theoretical framework to describe the electromagnetic properties of viscous charged fluids, consisting for example of electrons in certain solids or plasmas. We confirm that finite viscosity leads to multiple modes of evanescent electromagnetic waves at a given frequency, one of which is characterized by a negative index of refraction, as previously discussed in a simplified model by one of the authors. In particular we explain how optical spectroscopy can be used to probe the viscosity. We concentrate on the impact of this on the coefficients of refraction and reflection at the sample-vacuum interface. Analytical expressions are obtained relating the viscosity parameter to the reflection and transmission coefficients of light. We demonstrate that finite viscosity has the effect to decrease the reflectivity of a metallic surface, while the electromagnetic field penetrates more deeply. While on a phenomenological level there are similarities to the anomalous skin effect, the model presented here requires no particular assumptions regarding the corpuscular nature of the charge liquid. A striking consequence of the branching phenomenon into two degenerate modes is the occurrence in a half-infinite sample of oscillations of the electromagnetic field intensity as a function of distance from the interface.

Davide Forcella; Jan Zaanen; Davide Valentinis; Dirk van der Marel

2014-08-01

254

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

255

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

256

Wiring design for the control of electromagnetic interference (EMI)  

NASA Astrophysics Data System (ADS)

Wiring design is only one important aspect of EMI control. Other important areas for EMI are: circuit design, filtering, grounding, bonding, shielding, lighting, electrostatic discharge (ESD), transient suppression, and electromagnetic pulse (EMP). Topics covered include: wire magnetic field emissions at low frequencies; wire radiated magnetic field emissions at frequencies; wire design guidelines for EMI control; wire design guidelines for EMI control; high frequency emissions from cables; and pulse frequency spectra.

Kopasakis, George

1995-11-01

257

Wiring design for the control of electromagnetic interference (EMI)  

NASA Technical Reports Server (NTRS)

Wiring design is only one important aspect of EMI control. Other important areas for EMI are: circuit design, filtering, grounding, bonding, shielding, lighting, electrostatic discharge (ESD), transient suppression, and electromagnetic pulse (EMP). Topics covered include: wire magnetic field emissions at low frequencies; wire radiated magnetic field emissions at frequencies; wire design guidelines for EMI control; wire design guidelines for EMI control; high frequency emissions from cables; and pulse frequency spectra.

Kopasakis, George

1995-01-01

258

Electromagnetic Force as consequence of the Geometry of Minkowskian Spacetime  

E-print Network

By describing the dynamical evolution of a test charged particle in the presence of an electromagnetic field as a succession of infinitesimal Lorentz boosts and rotations it is possible to obtain the Lorentz Force of Electrodynamics. A consequence of this derivation at the classical level is that, given the existence of electric and magnetic fields, the form of the electromagnetic force acting on the particle can be regarded as arising from the geometry of Minkowskian spacetime.

J. Buitrago

2009-01-20

259

Electromagnetic WavesElectromagnetic Waves In this chapter we will review selected properties of electromagnetic waves since  

E-print Network

Electromagnetic WavesElectromagnetic Waves In this chapter we will review selected properties of electromagnetic waves since radar involves the transmission, propagation and scattering of EM waves by various is the electrostatic force between two point charges. #12;Electromagnetic WavesElectromagnetic Waves Electric fields

Rutledge, Steven

260

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

261

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.

262

Electromagnetic field and cosmic censorship  

E-print Network

We construct a gedanken experiment in which an extremal Kerr black hole interacts with a test electromagnetic field. Using Teukolsky's solutions for electromagnetic perturbations in Kerr spacetime, and the conservation laws imposed by the energy momentum tensor of the electromagnetic field and the Killing vectors of the spacetime, we prove that this interaction cannot convert the black hole into a naked singularity, thus cosmic censorship conjecture is not violated in this case.

Koray Düzta?

2013-12-27

263

Statistical Properties of Electromagnetic Environment in Wireless Networks, Intra-Network Electromagnetic Compatibility and Safety  

E-print Network

Statistical Properties of Electromagnetic Environment in Wireless Networks, Intra of electromagnetic environment in wireless networks affecting its intra- network electromagnetic compatibility-Network Electromagnetic Compatibility and Safety Vladimir Mordachev Belorussian State University of Informatics

Loyka, Sergey

264

Absorption cross section and Hawking radiation of the electromagnetic field with Weyl corrections  

E-print Network

We have investigated the absorption cross section and the Hawking radiation of electromagnetic field with Weyl correction in the background of a four-dimensional Schwarzschild black hole spacetime. Our results show that the properties of the absorption cross section and the Hawking radiation depend not only on the Weyl correction parameter, but also on the parity of the electromagnetic field, which is quite different from those of the usual electromagnetic field without Weyl correction in the four-dimensional spacetime. With increase of Weyl correction parameter, the absorption probability, the absorption cross section, the power emission spectra and the luminosity of Hawking radiation decreases with Weyl correction parameter for the odd-parity electromagnetic field and increases with the event-parity electromagnetic field.

Hao Liao; Songbai Chen; Jiliang Jing

2013-12-19

265

Electromagnetism on Anisotropic Fractals  

E-print Network

We derive basic equations of electromagnetic fields in fractal media which are specified by three indepedent fractal dimensions {\\alpha}_{i} in the respective directions x_{i} (i=1,2,3) of the Cartesian space in which the fractal is embedded. To grasp the generally anisotropic structure of a fractal, we employ the product measure, so that the global forms of governing equations may be cast in forms involving conventional (integer-order) integrals, while the local forms are expressed through partial differential equations with derivatives of integer order but containing coefficients involving the {\\alpha}_{i}'s. First, a formulation based on product measures is shown to satisfy the four basic identities of 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 Amp\\`ere 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, 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 and reduce to conventional forms for continuous media with Euclidean geometries upon setting the dimensions to integers.

Martin Ostoja-Starzewski

2011-06-08

266

Electromagnetic pump stator coil  

DOEpatents

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.

Fanning, Alan W. (San Jose, CA); Dahl, Leslie R. (Livermore, CA)

1996-01-01

267

Electromagnetic pump stator coil  

DOEpatents

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

268

Gravitation and electromagnetism  

E-print Network

Maxwell's equations comprise both electromagnetic and gravitational fields. The transverse part of the vector potential belongs to magnetism, the longitudinal one is concerned with gravitation. The Coulomb gauge indicates that longitudinal components of the fields propagate instantaneously. The delta-function singularity of the field of the divergence of the vector potential, referred to as the dilatation center, represents an elementary agent of gravitation. Viewing a particle as a source or a scattering center of the point dilatation, the Newton's gravitation law can be reproduced.

V. P. Dmitriyev

2002-07-23

269

Electromagnetic Probes in PHENIX  

E-print Network

Electromagnetic probes are arguably the most universal tools to study the different physics processes in high energy hadron and heavy ion collisions. In this paper we summarize recent measurements of real and virtual direct photons at central rapidity by the PHENIX experiment at RHIC in p+p, d+Au and Au+Au collisions. We also discuss the impact of the results and the constraints they put on theoretical models. At the end we report on the immediate as well as on the mid-term future of photon measurements at RHIC.

Gabor David

2006-09-21

270

Electromagnetic Meissner effect launcher  

NASA Technical Reports Server (NTRS)

An electromagnetic projectile launcher provides acceleration of a superconducting projectile through the diamagnetic repulsion of the superconducting projectile. A superconducting layer is provided aft of the projectile, either directly on the projectile or on a platform upon which the projectile is carried, and a traveling magnetic field is caused to propagate along a magnetic field drive coil in which the projectile is disposed. The resulting diamagnetic repulsion between the superconducting projectile and the traveling magnetic field causes the projectile to be propelled along the coil. In one embodiment, a segmented drive coil is used to generate the traveling magnetic field.

Robertson, Glen A. (inventor)

1991-01-01

271

"Decoupled" Proton NMR Spectra  

NASA Astrophysics Data System (ADS)

High-resolution proton NMR spectra are recorded in a new form where all resonances are singlets at the chemical-shift frequencies, with no spin-spin splittings. These "decoupled" proton spectra are derived from two-dimensional J spectra after real Fourier transformation (without frequency discrimination in F1) so that each spin multiplet lies along both the 45° and the 135° diagonal, forming a pattern similar to St. Andrew's cross, with C 4 symmetry. The chemical shifts are located by searching for these centers of symmetry with a postacquisition data-processing algorithm. This is designed to facilitate the separation of overlapping and interpenetrating spin multiplets. The method is illustrated with applications to the 400 MHz high-resolution proton spectra of dehydrotestosterone and 4-androsten-3,17-dione. It is also possible to separate the spectra of components in a mixture and this is illustrated by breaking down the spectrum of an aqueous solution of D-glucose into subspectra from the ? and ? anomers, in order to follow the time evolution of the mutarotation.

Woodley, M.; Freeman, R.

272

Electromagnetic interference onboard an electrically propelled spacecraft  

NASA Technical Reports Server (NTRS)

Electric and magnetic interference generated by a power conditioner and ion thruster were measured at JPL. Test results were judged by comparing the measured levels to the levels defined by the solar electric propulsion (SEP) specification that was derived from the existing mission oriented Viking-Orbiter 1975 and Mariner-Jupiter-Saturn 1977 electromagnetic compatibility specifications. In many areas the measured interference was excessive. In some cases, the cause of interference was identified. It was concluded that it should be possible on future designs to improve the EMI characteristics greatly at a modest penalty to weight and efficiency.

Macie, T. W.; Whittlesey, A. C.

1973-01-01

273

Metamaterials beyond electromagnetism.  

PubMed

Metamaterials are rationally designed man-made structures composed of functional building blocks that are densely packed into an effective (crystalline) material. While metamaterials are mostly associated with negative refractive indices and invisibility cloaking in electromagnetism or optics, the deceptively simple metamaterial concept also applies to rather different areas such as thermodynamics, classical mechanics (including elastostatics, acoustics, fluid dynamics and elastodynamics), and, in principle, also to quantum mechanics. We review the basic concepts, analogies and differences to electromagnetism, and give an overview on the current state of the art regarding theory and experiment-all from the viewpoint of an experimentalist. This review includes homogeneous metamaterials as well as intentionally inhomogeneous metamaterial architectures designed by coordinate-transformation-based approaches analogous to transformation optics. Examples are laminates, transient thermal cloaks, thermal concentrators and inverters, 'space-coiling' metamaterials, anisotropic acoustic metamaterials, acoustic free-space and carpet cloaks, cloaks for gravitational surface waves, auxetic mechanical metamaterials, pentamode metamaterials ('meta-liquids'), mechanical metamaterials with negative dynamic mass density, negative dynamic bulk modulus, or negative phase velocity, seismic metamaterials, cloaks for flexural waves in thin plates and three-dimensional elastostatic cloaks. PMID:24190877

Kadic, Muamer; Bückmann, Tiemo; Schittny, Robert; Wegener, Martin

2013-12-01

274

Metamaterials beyond electromagnetism  

NASA Astrophysics Data System (ADS)

Metamaterials are rationally designed man-made structures composed of functional building blocks that are densely packed into an effective (crystalline) material. While metamaterials are mostly associated with negative refractive indices and invisibility cloaking in electromagnetism or optics, the deceptively simple metamaterial concept also applies to rather different areas such as thermodynamics, classical mechanics (including elastostatics, acoustics, fluid dynamics and elastodynamics), and, in principle, also to quantum mechanics. We review the basic concepts, analogies and differences to electromagnetism, and give an overview on the current state of the art regarding theory and experiment—all from the viewpoint of an experimentalist. This review includes homogeneous metamaterials as well as intentionally inhomogeneous metamaterial architectures designed by coordinate-transformation-based approaches analogous to transformation optics. Examples are laminates, transient thermal cloaks, thermal concentrators and inverters, ‘space-coiling’ metamaterials, anisotropic acoustic metamaterials, acoustic free-space and carpet cloaks, cloaks for gravitational surface waves, auxetic mechanical metamaterials, pentamode metamaterials (‘meta-liquids’), mechanical metamaterials with negative dynamic mass density, negative dynamic bulk modulus, or negative phase velocity, seismic metamaterials, cloaks for flexural waves in thin plates and three-dimensional elastostatic cloaks.

Kadic, Muamer; Bückmann, Tiemo; Schittny, Robert; Wegener, Martin

2013-12-01

275

Electromagnetic Field Penetration Studies  

NASA Technical Reports Server (NTRS)

A numerical method is presented to determine electromagnetic shielding effectiveness of rectangular enclosure with apertures on its wall used for input and output connections, control panels, visual-access windows, ventilation panels, etc. Expressing EM fields in terms of cavity Green's function inside the enclosure and the free space Green's function outside the enclosure, integral equations with aperture tangential electric fields as unknown variables are obtained by enforcing the continuity of tangential electric and magnetic fields across the apertures. Using the Method of Moments, the integral equations are solved for unknown aperture fields. From these aperture fields, the EM field inside a rectangular enclosure due to external electromagnetic sources are determined. Numerical results on electric field shielding of a rectangular cavity with a thin rectangular slot obtained using the present method are compared with the results obtained using simple transmission line technique for code validation. The present technique is applied to determine field penetration inside a Boeing-757 by approximating its passenger cabin as a rectangular cavity filled with a homogeneous medium and its passenger windows by rectangular apertures. Preliminary results for, two windows, one on each side of fuselage were considered. Numerical results for Boeing-757 at frequencies 26 MHz, 171-175 MHz, and 428-432 MHz are presented.

Deshpande, M.D.

2000-01-01

276

THE ELECTROMAGNET. A SUPPLEMENTARY READING UNIT IN SCIENCE.  

ERIC Educational Resources Information Center

A SAMPLE READING UNIT IN SCIENCE IS PRESENTED FOR DISADVANTAGED STUDENTS AT THREE LEVELS OF ABILITY. THE READING LESSON IS COMPLETE WITH ILLUSTRATIONS OF ELECTROMAGNETS. FOLLOWING THE SUPPLEMENTARY UNIT ARE THREE SAMPLE OBJECTIVE TESTS FOR THE DIFFERENT ABILITY LEVELS. EACH SET OF QUESTIONS IS DESIGNED BOTH TO TEST KNOWLEDGE OF SCIENCE FACTS…

KINNEY, RICHARD; MOBILIZATION FOR YOUTH CURRICULUM STAFF

277

Electromagnetic radiation from beam-plasma instabilities  

NASA Technical Reports Server (NTRS)

A computer simulation is developed for the generation of electromagnetic radiation in an electron beam-plasma interaction. The plasma is treated as a two-dimensional finite system, and effects of a continuous nonrelativistic beam input are accounted for. Three momentum and three field components are included in the simulation, and an external magnetic field is excluded. EM radiation generation is possible through interaction among Langmuir oscillations, ion-acoustic waves, and the electromagnetic wave, producing radiation perpendicular to the beam. The radiation is located near the plasma frequency, and polarized with the E component parallel to the beam. The scattering of Langmuir waves caused by ion-acoustic fluctuations generates the radiation. Comparison with laboratory data for the three-wave interactions shows good agreement in terms of the radiation levels produced, which are small relative to the plasma thermal energy.

Pritchett, P. L.; Dawson, J. M.

1983-01-01

278

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

279

Televisions, Video Privacy, and Powerline Electromagnetic Interference  

E-print Network

Televisions, Video Privacy, and Powerline Electromagnetic Interference Miro Enev University that the power supplies of modern TVs produce discernible electromagnetic interference (EMI) signatures security, electromagnetic in- terference 1. INTRODUCTION It is known that consumer electronic devices can

Matsuoka, Yoky

280

Electromagnetic Characterization of MIMO Communication Systems  

E-print Network

electromagnetic interactions between the antenna arrays and the environment. To dissect the influence of various and the complex electromagnetic interactions between the antennas and the environment. SingleElectromagnetic Characterization of MIMO Communication Systems Kapil R. Dandekar, Sumant Kawale

Dong, Liang

281

TWO UNCONVENTIONAL APPROACHES TO ELECTROMAGNETIC INVERSION  

E-print Network

TWO UNCONVENTIONAL APPROACHES TO ELECTROMAGNETIC INVERSION Hierarchical Bayesian Inversion and Head, Department of Geophysics ii #12;ABSTRACT Electromagnetic methods are effective complementary approaches of electromagnetic inversion: hier- archical Bayesian inversion and inverse scattering series. We

Snieder, Roel

282

WebSpectra  

NSDL National Science Digital Library

This site, created by Barry C. Fam and Craig A. Merlic of the University of California - Los Angeles, was established to provide chemistry students with a library of spectroscopy problems. Interpretation of spectra is a technique that requires practice - this site provides 1H NMR and 13C NMR, DEPT, COSY and IR spectra of various compounds for students to interpret. Hopefully, these problems will provide a useful resource to better understand spectroscopy. The page was given a "Top 5% Chemistry Site" award for its usefulness and content. This is a great resource for anyone interested in either biochemistry or chemistry.

Fam, Barry C.; Merlic, Craig A.

2009-05-07

283

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

284

Engineering Sciences 151 Electromagnetic Communication  

E-print Network

) pyramidal horn antennas, Narda, Model 640 Large aperture (9 cm x 15 cm) pyramidal horn antennas, homemade-99 ELECTROMAGNETIC RADIATION CHARACTERISTICS Microwave Antenna Measurements OBJECTIVE: To study the radiation patterns and other characteristics of a variety of electromagnetic radiators (antennas). EXPERIMENTAL

Jones, R. Victor

285

On spin 2 electromagnetic interactions  

E-print Network

In this paper we (re)consider the problem of electromagnetic interactions for massless spin 2 particles and show that in $(A)dS$ spaces with non-zero cosmological constant it is indeed possible (at least in linear approximation) to switch on minimal electromagnetic interactions supplemented by third derivative non-minimal ones which are necessary to restore gauge invariance.

Yu. M. Zinoviev

2008-06-25

286

Electromagnetic neutrino: a short review  

E-print Network

A short review on selected issues related to the problem of neutrino electromagnetic properties is given. After a flash look at the theoretical basis of neutrino electromagnetic form factors, constraints on neutrino magnetic moments and electric millicharge from terrestrial experiments and astrophysical observations are discussed. We also focus on some recent studies of the problem and on perspectives.

Alexander I. Studenikin

2014-11-09

287

Electromagnetic neutrino: a short review  

E-print Network

A short review on selected issues related to the problem of neutrino electromagnetic properties is given. After a flash look at the theoretical basis of neutrino electromagnetic form factors, constraints on neutrino magnetic moments and electric millicharge from terrestrial experiments and astrophysical observations are discussed. We also focus on some recent studies of the problem and on perspectives.

Studenikin, Alexander I

2014-01-01

288

Particle swarm optimization in electromagnetics  

Microsoft Academic Search

The particle swarm optimization (PSO), new to the electromagnetics community, is a robust stochastic evolutionary computation technique based on the movement and intelligence of swarms. This paper introduces a conceptual overview and detailed explanation of the PSO algorithm, as well as how it can be used for electromagnetic optimizations. This paper also presents several results illustrating the swarm behavior in

Jacob Robinson; Yahya Rahmat-Samii

2004-01-01

289

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

290

Gravitational scattering of electromagnetic radiation  

NASA Technical Reports Server (NTRS)

The scattering of electromagnetic radiation by linearized gravitational fields is studied to second order in a perturbation expansion. The incoming electromagnetic radiation can be of arbitrary multipole structure, and the gravitational fields are also taken to be advanced fields of arbitrary multipole structure. All electromagnetic multipole radiation is found to be scattered by gravitational monopole and time-varying dipole fields. No case has been found, however, in which any electromagnetic multipole radiation is scattered by gravitational fields of quadrupole or higher-order multipole structure. This lack of scattering is established for infinite classes of special cases, and is conjectured to hold in general. The results of the scattering analysis are applied to the case of electromagnetic radiation scattered by a moving mass. It is shown how the mass and velocity may be determined by a knowledge of the incident and scattered radiation.

Brooker, J. T.; Janis, A. I.

1980-01-01

291

Electromagnetic reactions on light nuclei  

E-print Network

Electromagnetic reactions on light nuclei are fundamental to advance our understanding of nuclear structure and dynamics. The perturbative nature of the electromagnetic probes allows to clearly connect measured cross sections with the calculated structure properties of nuclear targets. We present an overview on recent theoretical ab-initio calculations of electron-scattering and photonuclear reactions involving light nuclei. We encompass both the conventional approach and the novel theoretical framework provided by chiral effective field theories. Because both strong and electromagnetic interactions are involved in the processes under study, comparison with available experimental data provides stringent constraints on both many-body nuclear Hamiltonians and electromagnetic currents. We discuss what we have learned from studies on electromagnetic observables of light nuclei, starting from the deuteron and reaching up to nuclear systems with mass number A=16.

Sonia Bacca; Saori Pastore

2014-07-13

292

Parallel algorithms for electromagnetic moment method formulations.  

E-print Network

??ENGLISH ABSTRACT: This dissertation investigates the moment method solution of electromagnetic radiation and scattering problems using parallel computers. In particular, electromagnetically large problems with arbitrary… (more)

Davidson, David Bruce

1991-01-01

293

1987 IEEE International Symposium on Electromagnetic Compatibility, Atlanta, GA, Aug. 25-27, 1987, Symposium Record  

NASA Astrophysics Data System (ADS)

Various papers on the state of the art in electromagnetic compatibility (EMC) are presented. The general topics addressed include: EMC analysis; simulators, facilities, and instrumentation; shield performance assessments; open area test sites; electromagnetic pulse; EMI suppression; and EMC measurements. Also considered are: cable coupling/crosstalk; radiated emission measurement concerns; electrostatic discharge; lightning/EMP; antenna-related EMC; statistical approach to EMC; and electromagnetic environment/system level EMC.

294

Electromagnetic propulsion for spacecraft  

NASA Technical Reports Server (NTRS)

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.

1993-01-01

295

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

296

Electromagnetically Clean Solar Arrays  

NASA Technical Reports Server (NTRS)

The term 'electromagnetically clean solar array' ('EMCSA') refers to a panel that contains a planar array of solar photovoltaic cells and that, in comparison with a functionally equivalent solar-array panel of a type heretofore used on spacecraft, (1) exhibits less electromagnetic interferences to and from other nearby electrical and electronic equipment and (2) can be manufactured at lower cost. The reduction of electromagnetic interferences is effected through a combination of (1) electrically conductive, electrically grounded shielding and (2) reduction of areas of current loops (in order to reduce magnetic moments). The reduction of cost is effected by designing the array to be fabricated as a more nearly unitary structure, using fewer components and fewer process steps. Although EMCSAs were conceived primarily for use on spacecraft they are also potentially advantageous for terrestrial applications in which there are requirements to limit electromagnetic interference. In a conventional solar panel of the type meant to be supplanted by an EMCSA panel, the wiring is normally located on the back side, separated from the cells, thereby giving rise to current loops having significant areas and, consequently, significant magnetic moments. Current-loop geometries are chosen in an effort to balance opposing magnetic moments to limit far-0field magnetic interactions, but the relatively large distances separating current loops makes full cancellation of magnetic fields problematic. The panel is assembled from bare photovoltaic cells by means of multiple sensitive process steps that contribute significantly to cost, especially if electomagnetic cleanliness is desired. The steps include applying a cover glass and electrical-interconnect-cell (CIC) sub-assemble, connecting the CIC subassemblies into strings of series-connected cells, laying down and adhesively bonding the strings onto a panel structure that has been made in a separate multi-step process, and mounting the wiring on the back of the panel. Each step increases the potential for occurrence of latent defects, loss of process control, and attrition of components. An EMCSA panel includes an integral cover made from a transparent material. The silicone cover supplants the individual cover glasses on the cells and serves as an additional unitary structural support that offers the advantage, relative to glass, of the robust, forgiving nature of the silcone material. The cover contains pockets that hold the solar cells in place during the lamination process. The cover is coated with indium tin oxide to make its surface electrically conductive, so that it serves as a contiguous, electrically grounded shield over the entire panel surface. The cells are mounted in proximity to metallic printed wiring. The painted-wiring layer comprises metal-film traces on a sheet of Kapton (or equivalent) polyimide. The traces include contact pads on one side of the sheet for interconnecting the cells. Return leads are on the opposite side of the sheet, positioned to form the return currents substantially as mirror images of, and in proximity to, the cell sheet currents, thereby minimizing magnetic moments. The printed-wiring arrangement mimics the back-wiring arrangement of conventional solar arrays, but the current-loop areas and the resulting magnetic moments are much smaller because the return-current paths are much closer to the solar-cell sheet currents. The contact pads are prepared with solder fo electrical and mechanical bonding to the cells. The pocketed cover/shield, the solar cells, the printed-wiring layer, an electrical bonding agent, a mechanical-bonding agent, a composite structural front-side face sheet, an aluminum honeycomb core, and a composite back-side face sheet are all assembled, then contact pads are soldered to the cells and the agents are cured in a single lamination process.

Stem, Theodore G.; Kenniston, Anthony E.

2008-01-01

297

Wavelets and electromagnetics  

NASA Technical Reports Server (NTRS)

Wavelets are an exciting new topic in applied mathematics and signal processing. This paper will provide a brief review of wavelets which are also known as families of functions with an emphasis on interpretation rather than rigor. We will derive an indirect use of wavelets for the solution of integral equations based techniques adapted from image processing. Examples for resistive strips will be given illustrating the effect of these techniques as well as their promise in reducing dramatically the requirement in order to solve an integral equation for large bodies. We also will present a direct implementation of wavelets to solve an integral equation. Both methods suggest future research topics and may hold promise for a variety of uses in computational electromagnetics.

Kempel, Leo C.

1992-01-01

298

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

299

Electromagnetic inverse scattering  

NASA Technical Reports Server (NTRS)

A three-dimensional electromagnetic inverse scattering identity, based on the physical optics approximation, is developed for the monostatic scattered far field cross section of perfect conductors. Uniqueness of this inverse identity is proven. This identity requires complete scattering information for all frequencies and aspect angles. A nonsingular integral equation is developed for the arbitrary case of incomplete frequence and/or aspect angle scattering information. A general closed-form solution to this integral equation is developed, which yields the shape of the scatterer from such incomplete information. A specific practical radar solution is presented. The resolution of this solution is developed, yielding short-pulse target resolution radar system parameter equations. The special cases of two- and one-dimensional inverse scattering and the special case of a priori knowledge of scatterer symmetry are treated in some detail. The merits of this solution over the conventional radar imaging technique are discussed.

Bojarski, N. N.

1972-01-01

300

Electromagnetic scattering theory  

NASA Technical Reports Server (NTRS)

Electromagnetic scattering theory is discussed with emphasis on the general stochastic variational principle (SVP) and its applications. The stochastic version of the Schwinger-type variational principle is presented, and explicit expressions for its integrals are considered. Results are summarized for scalar wave scattering from a classic rough-surface model and for vector wave scattering from a random dielectric-body model. Also considered are the selection of trial functions and the variational improvement of the Kirchhoff short-wave approximation appropriate to large size-parameters. Other applications of vector field theory discussed include a general vision theory and the analysis of hydromagnetism induced by ocean motion across the geomagnetic field. Levitational force-torque in the magnetic suspension of the disturbance compensation system (DISCOS), now deployed in NOVA satellites, is also analyzed using the developed theory.

Bird, J. F.; Farrell, R. A.

1986-01-01

301

Pulsed electromagnetic gas acceleration  

NASA Technical Reports Server (NTRS)

Experimental data were combined with one-dimensional conservation relations to yield information on the energy deposition ratio in a parallel-plate accelerator, where the downstream flow was confined to a constant area channel. Approximately 70% of the total input power was detected in the exhaust flow, of which only about 20% appeared as directed kinetic energy, thus implying that a downstream expansion to convert chamber enthalpy into kinetic energy must be an important aspect of conventional high power MPD arcs. Spectroscopic experiments on a quasi-steady MPD argon accelerator verified the presence of A(III) and the absence of A(I), and indicated an azimuthal structure in the jet related to the mass injection locations. Measurements of pressure in the arc chamber and impact pressure in the exhaust jet using a piezocrystal backed by a Plexiglas rod were in good agreement with the electromagnetic thrust model.

Jahn, R. G.; Vonjaskowsky, W. F.; Clark, K. E.

1971-01-01

302

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

303

Electromagnetic interference of power conditioners for solar electric propulsion  

NASA Technical Reports Server (NTRS)

Electrical, multikilowatt power conditioning (PC) equipment needed on board a spacecraft utilizing solar electric propulsion creates an electromagnetic environment that is potentially deterimental to the science, navigation, and radio communication hardware. Within the scope of the solar electric propulsion system technology program, three lightweight, 2.5-kW PCs were evaluated in terms of their electromagnetic characteristics. It was found that the levels of radiated and conducted interference exceeded the levels anticipated for a solar electric propulsion mission. These noise emissions, however, were the result of deficient interference design in these models, rather than a basic inability to control interference in this type of PC.

Whittlesey, A. C.; Macie, T. W.

1973-01-01

304

Direct recovery of fluctuation spectra from tomographic shear spectra  

SciTech Connect

Forthcoming experiments will enable us to determine high precision tomographic shear spectra. Matter density fluctuation spectra, at various z, should then be recovered from them, in order to constrain the model and determine the DE state equation. Available analytical expressions, however, do the opposite, enabling us to derive shear spectra from fluctuation spectra. Here we find the inverse expression, yielding density fluctuation spectra from observational tomographic shear spectra. The procedure involves SVD techniques for matrix inversion. We show in detail how the approach works and provide a few examples.

Mezzetti, Marino; Bonometto, Silvio A.; Murante, Giuseppe [Department of Physics, Astronomy Unit, Trieste University, Via Tiepolo 11, I 34143 Trieste (Italy); Casarini, Luciano, E-mail: mezzetti@oats.inaf.it, E-mail: bonometto@oats.inaf.it, E-mail: casarini@mib.infn.it, E-mail: murante@oats.inaf.it [Departamento de Fisica, UFES, Avenida Fernando Ferrari 514, Vitória, Espírito Santo (Brazil)

2012-06-01

305

Multi-scale roughness spectra of Mount St. Helens debris flows  

NASA Technical Reports Server (NTRS)

A roughness spectrum allows surface structure to be interpreted as a sum of sinusoidal components with differing wavelengths. Knowledge of the roughness spectrum gives insight into the mechanisms responsible for electromagnetic scattering at a given wavelength. Measured spectra from 10-year-old primary debris flow surfaces at Mount St. Helens conform to a power-law spectral model, suggesting that these surfaces are scaling over the measured range of spatial frequencies. Measured spectra from water-deposited surfaces deviate from this model.

Austin, Richard T.; England, Anthony W.

1993-01-01

306

Cascade Model of an Anomaly in Blazar Spectra at Very High Energy  

E-print Network

It is well known that the effect of gamma-ray absorption on extragalactic background light (EBL) is weakly expressed in the spectra of some blazars. It is shown that a secondary component generated by electromagnetic cascades might considerably decrease the statistical significance of this anomaly. Observational results indicate the existence of the cascade component in the spectra of extragalactic gamma-ray sources, thus supporting the proposed model.

Dzhatdoev, Timur

2015-01-01

307

Magic energies in auger electron spectra  

Microsoft Academic Search

The Auger electron spectra in ion-solid interaction exhibit ``magical'' energies. At those energies the electron emission spectrum does not depend on the kinetic energy of the incident ion. We explain this feature in terms of the level broadening of the incoming ion. Furthermore we show that the broadening is proportional to the original ion velocity and we find a new

R. Monreal; S. P. Apell

1993-01-01

308

Adjoint charge in electromagnetic field  

E-print Network

Making use of the octonion operator, the electromagnetic field generates an adjoint field theoretically. The source of adjoint field includes the adjoint charge and the adjoint current. The adjoint charge has an impact on the gravitational mass and the mass distribution in the electromagnetic field with its adjoint field, and causes further the predictions to departure slightly from the conservation of mass. The inferences can explain why the adjoint charge will influence the mass distribution in the gravitational field and electromagnetic field of celestial bodies. And then the adjoint charge can be considered as one kind of candidate for the dark matter.

Zi-Hua Weng

2009-10-07

309

Activity: Graphing Spectra  

NSDL National Science Digital Library

This activity introduces two different representations of spectra: the photographic representation, such as the rainbow, and the graphical representation used more often by astronomers. A rainbow is often given as an everyday example of a spectrum. Most students have seen a rainbow, so this example is used to help make the unfamiliar more familiar. However, the spectra that scientists use, which students will see in this lesson plan, appear very different than a rainbow. In this activity, students will explore for themselves two different representations of the same spectrum, noting advantages and disadvantages of each. They will explore the differences and similarities of both these representations, and will develop a more intuitive feel for a graphical representation, which may not yet be familiar to them.

2007-02-03

310

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

311

Barnacle Bill Spectra  

NASA Technical Reports Server (NTRS)

These IMP spectra show the characteristics of the rock surface measured by the Alpha Proton X-Ray Spectrometer (blue), the soil trapped in pits on the rock surface (red), and the deposit of bright drift on the top of the rock. The area measured by the APXS has the properties expected for nearly unweathered igneous rock, and the soil trapped in the pits is intermediate to the unweathered rock and the highly weathered drift material.

1997-01-01

312

Auroral Colors and Spectra  

NSDL National Science Digital Library

This site, co-produced by the NCAR High Altitude Observatory and the COMET Program, provides an explanation of how auroral colors are produced. The emission of specific colors of light is discussed in relation to oxygen and nitrogen emission spectra. Numerous images, graphs, and a video of an aurora are included. The site is part of "Physics of the Aurora: Earth Systems," an interactive learning module about the aurora.

2007-01-26

313

Analysis of electromagnetic emission from a dielectric sample under stepwise uniaxial compressive load  

NASA Astrophysics Data System (ADS)

We consider the regularities in the distribution of electromagnetic emission pulses from a sample subjected to stepwise loading upon uniaxial compression, using a multisensory monitoring system. It is shown that electromagnetic emission pulses differ in level, but are close in shape. Therefore, we employ the optimal filtration method for separating the electromagnetic emission pulses from noise. The distributions of pulsed response fluxes are plotted for each loading stage in the log-log coordinates. It is shown that for loads amounting to 60% of the breaking load, a power distribution of electromagnetic pulses is observed. The slope of the straight lines in the plots for the power distribution regularly decreases with the load.

Surzhikov, V. P.; Khorsov, N. N.

2015-01-01

314

Level anticrossing of impurity states in semiconductor nanocrystals.  

PubMed

The size dependence of the quantized energies of elementary excitations is an essential feature of quantum nanostructures, underlying most of their applications in science and technology. Here we report on a fundamental property of impurity states in semiconductor nanocrystals that appears to have been overlooked--the anticrossing of energy levels exhibiting different size dependencies. We show that this property is inherent to the energy spectra of charge carriers whose spatial motion is simultaneously affected by the Coulomb potential of the impurity ion and the confining potential of the nanocrystal. The coupling of impurity states, which leads to the anticrossing, can be induced by interactions with elementary excitations residing inside the nanocrystal or an external electromagnetic field. We formulate physical conditions that allow a straightforward interpretation of level anticrossings in the nanocrystal energy spectrum and an accurate estimation of the states' coupling strength. PMID:25369911

Baimuratov, Anvar S; Rukhlenko, Ivan D; Turkov, Vadim K; Ponomareva, Irina O; Leonov, Mikhail Yu; Perova, Tatiana S; Berwick, Kevin; Baranov, Alexander V; Fedorov, Anatoly V

2014-01-01

315

Level Anticrossing of Impurity States in Semiconductor Nanocrystals  

PubMed Central

The size dependence of the quantized energies of elementary excitations is an essential feature of quantum nanostructures, underlying most of their applications in science and technology. Here we report on a fundamental property of impurity states in semiconductor nanocrystals that appears to have been overlooked—the anticrossing of energy levels exhibiting different size dependencies. We show that this property is inherent to the energy spectra of charge carriers whose spatial motion is simultaneously affected by the Coulomb potential of the impurity ion and the confining potential of the nanocrystal. The coupling of impurity states, which leads to the anticrossing, can be induced by interactions with elementary excitations residing inside the nanocrystal or an external electromagnetic field. We formulate physical conditions that allow a straightforward interpretation of level anticrossings in the nanocrystal energy spectrum and an accurate estimation of the states' coupling strength. PMID:25369911

Baimuratov, Anvar S.; Rukhlenko, Ivan D.; Turkov, Vadim K.; Ponomareva, Irina O.; Leonov, Mikhail Yu.; Perova, Tatiana S.; Berwick, Kevin; Baranov, Alexander V.; Fedorov, Anatoly V.

2014-01-01

316

Level Anticrossing of Impurity States in Semiconductor Nanocrystals  

NASA Astrophysics Data System (ADS)

The size dependence of the quantized energies of elementary excitations is an essential feature of quantum nanostructures, underlying most of their applications in science and technology. Here we report on a fundamental property of impurity states in semiconductor nanocrystals that appears to have been overlooked--the anticrossing of energy levels exhibiting different size dependencies. We show that this property is inherent to the energy spectra of charge carriers whose spatial motion is simultaneously affected by the Coulomb potential of the impurity ion and the confining potential of the nanocrystal. The coupling of impurity states, which leads to the anticrossing, can be induced by interactions with elementary excitations residing inside the nanocrystal or an external electromagnetic field. We formulate physical conditions that allow a straightforward interpretation of level anticrossings in the nanocrystal energy spectrum and an accurate estimation of the states' coupling strength.

Baimuratov, Anvar S.; Rukhlenko, Ivan D.; Turkov, Vadim K.; Ponomareva, Irina O.; Leonov, Mikhail Yu.; Perova, Tatiana S.; Berwick, Kevin; Baranov, Alexander V.; Fedorov, Anatoly V.

2014-11-01

317

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

318

PHYSICS 417. Electromagnetism. Lecturer: Tim Gorringe.  

E-print Network

PHYSICS 417. Electromagnetism. Lecturer: Tim Gorringe. Office: CP273. Phone: 257-8740. Textbook: Electromagnetic Fields, R. Wangsness, 2nd Ed. Web page www.pa.uky.edu/gorringe/phy417/index.html Class hours: MWF-semester sequence on electromagnetic theory. 1 Course Objectives. The electromagnetic field binds electrons

MacAdam, Keith

319

PHYSICS 416. Electromagnetism. Lecturer: Tim Gorringe.  

E-print Network

PHYSICS 416. Electromagnetism. Lecturer: Tim Gorringe. Office: CP 273. Phone: 257-8740. Textbook: Electromagnetic Fields, R. Wangsness, 2nd Ed. Web page www.pa.uky.edu/gorringe/phy416/index.html Class hours: MWF-semester sequence on electromagnetic theory. 1 416/417 Course Objectives. The electromagnetic field binds electrons

MacAdam, Keith

320

Measuring spinal motion in rowers: the use of an electromagnetic device  

Microsoft Academic Search

Objective. To determine whether a skin-mounted electromagnetic measurement device can be used to measure lumbar spinal motion in rowers and discriminate between variations in technique.Design. The lumbar spinal kinematics of elite level rowers were assessed with an electromagnetic device (Flock of Birds™) during ergometer training using five technique variants. The system was correlated with sagittal MRI imaging of the lumbar

Anthony M. J Bull; Alison H McGregor

2000-01-01

321

Interference during the use of an electromagnetic tracking system under OR conditions  

Microsoft Academic Search

Many computer-assisted surgery applications use electromagnetic tracking devices and several sources of interference may reduce the accuracy of this type of system in clinical situations. This study aims to quantify interference sources in an operating room (OR) and determine if their impact on the tracking system is excessive for applications requiring millimetric accuracy. Electromagnetic noise levels were measured in a

François Poulin; L.-P. Amiot

2002-01-01

322

Multi-scale approach for the electromagnetic modelling of MEMS-controlled reflectarrays  

Microsoft Academic Search

A new approach, named the scale changing technique, is performed here for the electromagnetic modelling of reflect arrays controlled by radio-frequency micro- electromechanical switches. Based on the partition of the reflectarray surface in planar sub-domains with various scale levels, this technique derives the phase- shift dynamics from the simple cascade of networks, each network describing the electromagnetic coupling between two

H. Aubert; N. Raveu; E. Perret; H. Legay

2006-01-01

323

A Static Multi-hop Underwater Wireless Sensor Network Using RF Electromagnetic Communications  

Microsoft Academic Search

Most underwater sensor networks choose acoustics as the medium for wireless transmission. However, electromagnetic waves also offer great merits for transmission in special underwater environment. A small scale wireless sensor network is deployed using electromagnetic waves with a multi-hop static topology under shallow water conditions where there is a high level of sediment and aeration in the water column. Data

Xianhui Che; Ian Wells; Paul Kear; Gordon Dickers; Xiaochun Gong; Mark Rhodes

2009-01-01

324

Monolithic electromagnetic modeling of multi-scale structures based on scale-changing networks  

Microsoft Academic Search

The monolithic electromagnetic modeling called the scale changing technique is based on the cascade of multi-modal scale changing networks, each network modeling the electromagnetic coupling between two successive scale levels. This new technique is efficient for solving 2D multi-scale boundary value problems and is suitable for distributed (parallel) computing.

Hervé Aubert

2008-01-01

325

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

326

[The characteristics of the electromagnetic situation close to overhead electric power transmission lines in St. Petersburg].  

PubMed

According to task by Environmental Protection Department of St. Petersburg Municipal Administration, levels of electromagnetic fields induced by high-voltage electric power lines were measured in development lands of St. Petersburg. The authors present hygienic evaluation of electromagnetic fields intensity, match calculated and actual values of magnetic induction of occupational magnetic fields. PMID:9885493

Nikitina, V N; Marchenko, E A; Kolesnikov, G A; Naumova, T M; Shubnikova, N N; Cherniavski?, A A

1998-01-01

327

Specifying lifecycle electromagnetic and physical environments - to help design and test for EMC for functional safety  

Microsoft Academic Search

Certain kinds of equipment must maintain sufficiently low risks to users and third parties over their entire lifecycles, despite at least one fault, and despite foreseeable misuse. Where electromagnetic interference (EMI) could foreseeably have an effect on such equipment, it will need to maintain an adequate level of electromagnetic (EM) immunity over its lifecycle. This is the concern of 'EMC

EurIng Keith Armstrong

2005-01-01

328

Characterization of the cumulative effects of ultrawideband technology on the electromagnetic environment  

Microsoft Academic Search

In this paper, we describe the results of a study carried out to evaluate the cumulative effects of devices using ultrawideband (UWB) technology upon the electromagnetic environment, specifically their contributions to the raising of the ambient levels. These effects have been quantified, and an electromagnetic compatibility (EMC) methodology developed to assess the interference potential of UWB devices with respect to

Q. Zeng; A. Chubukjian

2003-01-01

329

Fault detection of a flight control computer in a harsh electromagnetic environment  

Microsoft Academic Search

Verifying functional integrity of flight control computers (FCC) in harsh electromagnetic environments is a key issue in development, certification, and operation of systems performing flight critical functions. A strategy is being developed for real-time detection of control command errors caused by electromagnetic environments in FCCs during validation testing. A system level approach to FCC fault detection and mitigation in real

Kenneth W. Eure

2001-01-01

330

A distributed system of mobile sensors for electromagnetic field measurements in urban environments  

Microsoft Academic Search

A mobile distributed system for the monitoring and mapping of electromagnetic field exposure levels in urban environments is presented. The main objective of the system, in accordance with current regulations, is to use mapped values to highlight 'critical' locations within the investigated area where the environmental electromagnetic field amplitude is higher, and that therefore need careful observation and monitoring or

Claudio De Capua; Nicola Pasquino; Antonio Maria Rinaldi; Alessandro Scala

2004-01-01

331

Stresa, Italy, 25-27 April 2007 STEP-UP CONVERTER FOR ELECTROMAGNETIC VIBRATIONAL ENERGY  

E-print Network

to convert the ac-generated voltage to a usable dc level. In particular an electromagnetic generator with such a converter have not been investigated. There are different topologies which can be used to perform the ac-dc conversion required to convert the low voltage AC generated by an electromagnetic vibrational generator

Boyer, Edmond

332

Electromagnetic Dissociation and Space Radiation  

E-print Network

Relativistic nucleus-nucleus reactions occur mainly through the Strong or Electromagnetic (EM) interactions. Transport codes often neglect the latter. This work shows the importance of including EM interactions for space radiation applications.

John W. Norbury; Khin Maung Maung

2006-12-08

333

Conical electromagnetic radiation flux concentrator  

NASA Technical Reports Server (NTRS)

Concentrator provides method of concentrating a beam of electromagnetic radiation into a smaller beam, presenting a higher flux density. Smaller beam may be made larger by sending radiation through the device in the reverse direction.

Miller, E. R.

1972-01-01

334

Electromagnetic Interference In New Aircraft  

NASA Technical Reports Server (NTRS)

Report reviews plans to develop tests and standards to ensure that digital avionics systems in new civil aircraft immune to electromagnetic interference (EMI). Updated standards reflect more severe environment and vulnerabilities of modern avionics.

Larsen, William E.

1991-01-01

335

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

336

Electromagnetic Showers at High Energy  

ERIC Educational Resources Information Center

Some of the properties of electromagnetic showers observed in an experimental study are illustrated. Experimental data and results from quantum electrodynamics are discussed. Data and theory are compared using computer simulation. (BB)

Loos, J. S.; Dawson, S. L.

1978-01-01

337

Seismo-Electromagnetic Study in China  

NASA Astrophysics Data System (ADS)

In this paper, I made a brief review on the earthquake-related electromagnetic study in China, especially focusing on geo-electromagnetic observation and empirical prediction based on the observation data. After introducing briefly the roles of China Earthquake Administration (CEA) in seismo-electromagnetic study in China, I summarized various electromagnetic observations (e.g., apparent resistivity, geoelectric potential, geomagnetic field, electromagnetic disturbance, etc.). As the potential application, I showed the cases of the empirical prediction based on the observed electromagnetic data associated with some earthquakes in China. This paper may provide some useful information for those who want to know the general situation of seismo-electromagnetic study in China.

Huang, Qinghua

338

Electromagnetically induced grating with maximal atomic coherence  

SciTech Connect

We describe theoretically an atomic diffraction grating that combines an electromagnetically induced grating with a coherence grating in a double-{Lambda} atomic system. With the atom in a condition of maximal coherence between its lower levels, the combined gratings simultaneously diffract both the incident probe beam as well as the signal beam generated through four-wave mixing. A special feature of the atomic grating is that it will diffract any beam resonantly tuned to any excited state of the atom accessible by a dipole transition from its ground state.

Carvalho, Silvania A.; Araujo, Luis E. E. de [Instituto de Fisica ''Gleb Wataghin'', Universidade Estadual de Campinas, Campinas-SP, 13083-859 Sao Paulo (Brazil)

2011-10-15

339

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

340

Black Hole Thermodynamics and Electromagnetism  

E-print Network

We show a strong parallel between the Hawking, Beckenstein black hole Thermodynamics and electromagnetism: When the gravitational coupling constant transform into the electromagnetic coupling constant, the Schwarzchild radius, the Beckenstein temperature, the Beckenstein decay time and the Planck mass transform to respectively the Compton wavelength, the Hagedorn temperature, the Compton time and a typical elementary particle mass. The reasons underlying this parallalism are then discussed in detail.

Burra G. Sidharth

2005-07-15

341

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

342

Electromagnetic suspension and levitation techniques  

Microsoft Academic Search

A comprehensive account is given of state-of-the-art and prospective electromagnetic and electromechanical suspension\\/levitation technologies, using both conventional and superconducting materials, with a view both to their performance improvements over differently grounded technologies and their economic feasibility. In addition to passenger-carrying vehicles, controlled DC electromagnet technologies have been applied to frictionless magnetic bearings, flow meters, conveyor systems, high-speed machine tool spindles,

B. V. Jayawant

1988-01-01

343

Electromagnetically driven peristaltic pump  

DOEpatents

An electromagnetic peristaltic pump apparatus may comprise a main body section having an inlet end and an outlet end and a flexible membrane which divides the main body section into a first cavity and a second cavity. The first cavity is in fluid communication with the inlet and outlet ends of the main body section. The second cavity is not in fluid communication with the first cavity and contains an electrically conductive fluid. The second cavity includes a plurality of electrodes which are positioned within the second cavity generally adjacent the flexible membrane. A magnetic field generator produces a magnetic field having a plurality of flux lines at least some of which are contained within the second cavity of the main body section and which are oriented generally parallel to a flow direction in which a material flows between the inlet and outlet ends of the main body section. A control system selectively places a voltage potential across selected ones of the plurality of electrodes to deflect the flexible membrane in a wave-like manner to move material contained in the first cavity between the inlet and outlet ends of the main body section.

Marshall, Douglas W. (Blackfoot, ID)

2000-01-01

344

Electromagnetic Calorimeter for HADES  

E-print Network

We propose to build the Electromagnetic calorimeter for the HADES di-lepton spectrometer. It will enable to measure the data on neutral meson production from nucleus-nucleus collisions, which are essential for interpretation of dilepton data, but are unknown in the energy range of planned experiments (2-10 GeV per nucleon). The calorimeter will improve the electron-hadron separation, and will be used for detection of photons from strange resonances in elementary and HI reactions. Detailed description of the detector layout, the support structure, the electronic readout and its performance studied via Monte Carlo simulations and series of dedicated test experiments is presented. The device will cover the total area of about 8 m^2 at polar angles between 12 and 45 degrees with almost full azimuthal coverage. The photon and electron energy resolution achieved in test experiments amounts to 5-6%/sqrt(E[GeV]) which is sufficient for the eta meson reconstruction with S/B ratio of 0.4% in Ni+Ni collisions at 8 AGeV. A purity of the identified leptons after the hadron rejection, resulting from simulations based on the test measurements, is better than 80% at momenta above 500 MeV/c, where time-of-flight cannot be used.

W. Czyzycki; E. Epple; L. Fabbietti; M. Golubeva; F. Guber; A. Ivashkin; M. Kajetanowicz; A. Krasa; F. Krizek; A. Kugler; K. Lapidus; E. Lisowski; J. Pietraszko; A. Reshetin; P. Salabura; Y. Sobolev; J. Stanislav; P. Tlusty; T. Torrieri; M. Traxler

2011-09-26

345

Pulsed electromagnetic gas acceleration  

NASA Technical Reports Server (NTRS)

Detailed measurements of the axial velocity profile and electromagnetic structure of a high power, quasi-steady MPD discharge are used to formulate a gasdynamic model of the acceleration process. Conceptually dividing the accelerated plasma into an inner flow and an outer flow, it is found that more than two-thirds of the total power in the plasma is deposited in the inner flow, accelerating it to an exhaust velocity of 12.5 km/sec. The outer flow, which is accelerated to a velocity of only 6.2 km/sec, appears to provide a current conduction path between the inner flow and the anode. Related cathode studies have shown that the critical current for the onset of terminal voltage fluctuations, which was recently shown to be a function of the cathode area, appears to reach an asymptote for cathodes of very large surface area. Detailed floating potential measurements show that the fluctuations are confined to the vicinity of the cathode and hence reflect a cathode emission process rather than a fundamental limit on MPD performance.

Jahn, R. G.; Vonjaskowsky, W. F.; Clark, K. E.

1974-01-01

346

The CPLEAR electromagnetic calorimeter  

NASA Astrophysics Data System (ADS)

A large-acceptance lead/gas sampling electromagnetic calorimeter (ECAL) was constructed for the CPLEAR experiment to detect photons from decays of ? 0s with momentum p?0 ? 800 MeV/ c. The main purpose of the ECAL is to determine the decay vertex of neutral-kaon decays K 0 ? ? 0? 0 ? 4? and K 0 ? ? 0? 0? 0 ? 6?. This requires a position-sensitive photon detector with high spatial granularity in r-, ?-, and z-coordinates. The ECAL - a barrel without end-caps located inside a magnetic field of 0.44 T - consists of 18 identical concentric layers. Each layer of {1}/{3} radiation length ( X0) contains a converter plate followed by small cross-section high-gain tubes of 2640 mm active length which are sandwiched by passive pick-up strip plates. The ECAL, with a total of 6 X0 has an energy resolution of {?(E)}/{E} ? {13%}/{(E( GeV) }and a position resolution of 4.5 mm for the shower foot. The shower topology allows separation of electrons from pions. The design, construction, read-out electronics, and performance of the detector are described.

Adler, R.; Backenstoss, G.; Bal, F.; Behnke, O.; Bloch, P.; Damianoglou, D.; Dechelette, P.; Dröge, M.; Eckart, B.; Felder, C.; Fetscher, W.; Fidecaro, M.; Garreta, D.; Gerber, H.-J.; Gumplinger, P.; Guyon, D.; Johner, H. U.; Lofstedt, B.; Kern, J.; Kokkas, P.; Krause, H.; Mall, U.; Marin, C.; Nanni, F.; Pagels, B.; Pavlopoulos, P.; Petit, P.; Polivka, G.; Rheme, Ch.; Ruf, T.; Santoni, C.; Schaller, L. A.; Schopper, A.; Tauscher, L.; Tschopp, H.; Weber, P.; Wendler, H.; Witzig, C.; Wolter, M.; Cplear Collaboration

1997-02-01

347

Electron beam injection during active experiments. I - Electromagnetic wave emissions  

NASA Technical Reports Server (NTRS)

The wave emissions produced in Echo 7 experiment by active injections of electron beams were investigated to determine the properties of the electromagnetic and electrostatic fields for both the field-aligned and cross-field injection in such experiments and to evaluate the sources of free energy and relative efficiencies for the generation of the VLF and HF emissions. It is shown that, for typical beam energies in active experiments, electromagnetic effects do not substantially change the bulk properties of the beam, spacecraft charging, and plasma particle acceleration. Through simulations, beam-generated whistlers; fundamental z-mode and harmonic x-mode radiation; and electrostatic electron-cyclotron, upper-hybrid, Langmuir, and lower-hybrid waves were identified. The characteristics of the observed wave spectra were found to be sensitive to both the ratio of the electron plasma frequency to the cyclotron frequency and the angle of injection relative to the magnetic field.

Winglee, R. M.; Kellogg, P. J.

1990-01-01

348

Thermo-electromagnetic sound transducer based on carbon nanotube sheet  

NASA Astrophysics Data System (ADS)

Multi-walled carbon nanotube sheet stretched between conductive rods was placed in magnetic field and excited with alternating electrical current to obtain hybrid thermo-electromagnetic sound transducer (TEMST). Unlike quite common thermoacoustic (TA) device capable of conversion of heat into acoustic signal, sound generation in explored design is provided by diaphragm-like oscillations of thermally excited sheet induced by the electromagnetic Lorentz force. This results in the interference of TA and Lorentz force-driven contributions causing substantial variation of intensity and spatial distribution of first harmonic of emitted signal. Acoustic spectra and sound propagation direction for TEMST device can be controlled by applied bias voltage that is beneficial for diverse sound management applications. Observed dependence of acoustic amplitude on field strength can be used for magnetic sensing.

Kozlov, Mikhail; Oh, Jiyoung

2014-09-01

349

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

350

A new electromagnetic code for ICRF antenna in EAST  

E-print Network

The demand for an effective tool to help in the design of ion cyclotron radio frequency (ICRF) antenna system for fusion experiment has driven the development of predictive codes. A new electromagnetic code based on the method of moments (MOM) is described in the paper. The code computes the electromagnetic field by the solution of the electric field integral equation. The structure of ICRF antennas are discretized with triangular mesh. By using the new code, the scattering parameter and the surface current are given and compared with the result by commercial code CST. Moreover, the power spectra are studied with different toroidal phases for heating and current drive. Good agreement of simulation results between the new code and CST are obtained. The code has been validated against CST for EAST ICRF antenna.

Yang, Hua; Dong, Sa; Zhang, Xin-Jun; Zhao, Yan-Ping; Shang, Lei

2015-01-01

351

Einstein spectra of quasars  

NASA Technical Reports Server (NTRS)

The results of the initial stage of the CfA survey of quasar energy distributions are reviewed. Einstein imaging proportional counter spectra of 33 quasars have been studied by fitting a single power law slope and absorption by an equivalent column density of neutral hydrogen. Comparison with the higher energy HEAO-A2 data leads to a two-component model for the X-ray spectrum. The X-ray column density is systematically lower than the 21-cm measured Galactic column density along the same line of sight.

Wilkes, Belinda J.

1988-01-01

352

Observation of atomic localization using electromagnetically induced transparency  

Microsoft Academic Search

We present a proof-of-principle experiment in which the population of an atomic level is spatially localized using the technique of electromagnetically induced transparency (EIT). The key idea is to utilize the sensitive dependence of the dark state of EIT on the intensity of the coupling laser beam. By using a sinusoidal intensity variation (standing wave), we demonstrate that the population

N. A. Proite; Z. J. Simmons; D. D. Yavuz

2011-01-01

353

Creating an electromagnetic transients program in MATLAB: MatEMTP  

Microsoft Academic Search

The traditional method for developing electric network analysis computer programs is based on coding using a conventional computer language: FORTRAN, C or Pascal. The programming language of the EMTP (Electromagnetic Transients Program) is FORTRAN-77. Such a program has a closed architecture and uses a large number of code lines to satisfy requirements ranging from low level data manipulation to the

Jean Mahseredjian; Fernando Alvarado

1997-01-01

354

Discussion paper: An electromagnetic mechanism of solar-terrestrial relations  

Microsoft Academic Search

[1] Studies of the electromagnetic mechanism of solar-terrestrial relations and their influence on the states of separate systems of a human organism are discussed. Quantitative estimates of the level of statistical relations between the characteristics of the cardiovascular system and human brain activity and parameters of the fundamental modes of the near-Earth resonators have been obtained.

A. G. Kolesnik; A. S. Borodin; S. A. Kolesnik; S. V. Pobachenko

2005-01-01

355

Nonionizing electromagnetic wave effects in biological materials and systems  

Microsoft Academic Search

Electromagnetic waves from the lower radio frequencies up through the optical spectrum can generate a myriad of effects and responses in biological specimens. Some of these effects can be harmful to man at high radiation intensities, producing burns, cataracts, chemical changes, etc. Biological effects have been reported at lower radiation intensities, but it is not now known if low-level effects

C. C. Johnson; A. W. Guy

1972-01-01

356

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

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

Directive Wavefronts Inside a Time Reversal Electromagnetic Chamber  

E-print Network

to verify the radiated-immunity of equipments such as transverse electromagnetic (TEM) and gigahertz TEM cells [1], used for immunity testing with TEM fields. Also, the use of anechoic and semi that testing in an AC may lead to stress levels of electronic components inside the equipment that are 10-15 d

Boyer, Edmond

359

Interference spectra transformation of counter-propagating pulses propagating through a dielectric slab  

NASA Astrophysics Data System (ADS)

A phenomenon of spectra transformation of counter-propagating electromagnetic pulses which propagate through a dielectric slab is studied. The spectra transformation occurs due to the interference energy flux which exists during the propagation of pulses through a slab. The physical conditions (time matching, amplitude matching and existence of the slab critical size) under which the maximal interference energy flux is observed are discussed. It is found that the interference energy flux modulates the spectra of the initial signals and transfers energy through the slab unequally at different frequencies. The energy transfer does not occur at multiple frequencies which correspond to the reflectionless passage of monochromatic waves through the slab.

Kochetov, Bogdan A.

2014-07-01

360

Immunizing digital systems against electromagnetic interference  

SciTech Connect

This paper discusses the development of the technical basis for acceptance criteria applicable to the immunization of digital systems against electromagnetic interference (EMI). The work is sponsored by the US Nuclear Regulatory Commission and stems from the safety-related issues that need to be addressed as a result of the application of digital instrumentation and control systems in nuclear power plants. Designers of digital circuits are incorporating increasingly higher clock frequencies and lower logic level voltages, thereby leading to potentially greater susceptibility of spurious interference being misinterpreted as legitimate logic. Development of the technical basis for acceptance criteria to apply to these digital systems centers around establishing good engineering practices to ensure that sufficient levels of electromagnetic compatibility (EMC) are maintained between the nuclear power plant's electronic and electromechanical systems. First, good EMC design and installation practices are needed to control the emissions from interference sources and thereby their impact on other nearby circuits and systems. Secondly, a test and evaluation program is needed to outline the EMI tests to be performed, the associated test methods to be followed, and adequate test limits to ensure that the circuit or system under test meets the recommended guidelines. Test and evaluation should be followed by periodic maintenance to assess whether the recommended EMI control practices continue to be adhered to as part of the routine operation of the nuclear power plant. By following these steps, the probability of encountering safety-related instrumentation problems associated with EMI will be greatly reduced.

Ewing, P.D.; Korsah, K. (Oak Ridge National Lab., TN (United States)); Antonescu, C. (Nuclear Regulatory Commission, Washington, DC (United States). Office of Nuclear Regulatory Research)

1993-01-01

361

Immunizing digital systems against electromagnetic interference  

SciTech Connect

This paper discusses the development of the technical basis for acceptance criteria applicable to the immunization of digital systems against electromagnetic interference (EMI). The work is sponsored by the US Nuclear Regulatory Commission and stems from the safety-related issues that need to be addressed as a result of the application of digital instrumentation and control systems in nuclear power plants. Designers of digital circuits are incorporating increasingly higher clock frequencies and lower logic level voltages, thereby leading to potentially greater susceptibility of spurious interference being misinterpreted as legitimate logic. Development of the technical basis for acceptance criteria to apply to these digital systems centers around establishing good engineering practices to ensure that sufficient levels of electromagnetic compatibility (EMC) are maintained between the nuclear power plant`s electronic and electromechanical systems. First, good EMC design and installation practices are needed to control the emissions from interference sources and thereby their impact on other nearby circuits and systems. Secondly, a test and evaluation program is needed to outline the EMI tests to be performed, the associated test methods to be followed, and adequate test limits to ensure that the circuit or system under test meets the recommended guidelines. Test and evaluation should be followed by periodic maintenance to assess whether the recommended EMI control practices continue to be adhered to as part of the routine operation of the nuclear power plant. By following these steps, the probability of encountering safety-related instrumentation problems associated with EMI will be greatly reduced.

Ewing, P.D.; Korsah, K. [Oak Ridge National Lab., TN (United States); Antonescu, C. [Nuclear Regulatory Commission, Washington, DC (United States). Office of Nuclear Regulatory Research

1993-02-01

362

Magnetically coupled electromagnetically induced transparency analogy of dielectric metamaterial  

SciTech Connect

In this manuscript, we experimentally demonstrate magnetically coupled electromagnetically induced transparency (EIT) analogy effect inside dielectric metamaterial. In contrast to previous studies employed different metallic topological microstructures to introduce dissipation loss change, barium strontium titanate, and calcium titanate (CaTiO{sub 3}) are chosen as the bright and dark EIT resonators, respectively, due to their different intrinsic dielectric loss. Under incident magnetic field excitation, dielectric metamaterial exhibits an EIT-type transparency window around 8.9?GHz, which is accompanied by abrupt change of transmission phase. Numerical calculations show good agreement with experiment spectra and reveal remarkably increased group index, indicating potential application in slow light.

Zhang, Fuli, E-mail: fuli.zhang@nwpu.edu.cn; He, Xuan [Key Laboratory of Space Applied Physics and Chemistry, Ministry of Education and Department of Applied Physics, School of Science, Northwestern Polytechnical University, Xi'an 710072 (China); Zhao, Qian [State Key Laboratory of Tribology, Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Lan, Chuwen; Zhou, Ji [State Key Laboratory of New Ceramics and Fine Processing, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Zhang, Weihong, E-mail: zhangwh@nwpu.edu.cn; Qiu, Kepeng [School of Mechanical Engineering, P.O. Box 552, Northwestern Polytechnical University, Xi'an 710072 (China)

2014-03-31

363

Electromagnetically Induced Transparency from a Single Atom in Free Space  

E-print Network

We report an absorption spectroscopy experiment and the observation of electromagnetically induced transparency from a single trapped atom. We focus a weak and narrowband Gaussian light beam onto an optically cooled Barium ion using a high numerical aperture lens. Extinction of this beam is observed with measured values of up to 1.3 %. We demonstrate electromagnetically induced transparency of the ion by tuning a strong control beam over a two-photon resonance in a three-level lambda-type system. The probe beam extinction is inhibited by more than 75 % due to population trapping.

L. Slodicka; G. Hetet; S. Gerber; M. Hennrich; R. Blatt

2010-05-18

364

Step-up converter for electromagnetic vibrational energy scavenger  

E-print Network

This paper introduces a voltage multiplier (VM) circuit which can step up a minimum voltage of 150 mV (peak). The operation and characteristics of this converter circuit are described. The voltage multiplier circuit is also tested with micro and macro scale electromagnetic vibrational generators and the effect of the VM on the optimum load conditions of the electromagnetic generator is presented. The measured results show that 85% efficiency can be achieved from this VM circuit at a power level of 18 ?W.

Saha, C; Godsell, J; Carlioz, L; Wang, N; Mccloskey, P; Beeby, S; Tudor, J; Torah, Russel

2008-01-01

365

Terahertz electromagnetic wave generation and amplification by an electron beam in the elliptical plasma waveguides with dielectric rod  

SciTech Connect

The propagation of electromagnetic waves in an elliptical plasma waveguide including strongly magnetized plasma column and a dielectric rod is investigated. The dispersion relation of guided hybrid electromagnetic waves is obtained. Excitation of the waves by a thin annular relativistic elliptical electron beam will be studied. The time growth rate of electromagnetic waves is obtained. The effects of relative permittivity constant of dielectric rod, radius of dielectric rod, accelerating voltage, and current density of the annular elliptical beam on the growth rate and the frequency spectra are numerically presented.

Rahmani, Z., E-mail: z.rahmani@kashanu.ac.ir; Jazi, B. [Department of Laser and Photonics, Faculty of Physics, University of Kashan, Kashan (Iran, Islamic Republic of); Heidari-Semiromi, E. [Department of Condense Matter, Faculty of Physics, University of Kashan, Kashan (Iran, Islamic Republic of)

2014-09-15

366

An analysis of VLF electric field spectra measured in Titan's atmosphere by the Huygens probe  

NASA Astrophysics Data System (ADS)

A numerical simulation of Titan's electromagnetic cavity in the VLF band is carried out using the Transmission Line Matrix (TLM) method, with the aim of assessing the VLF electric field spectra sent by the Huygens probe. In an Earth-like model, successive peaks would be expected in the spectra, associated with multiple reflections of the electromagnetic wave on the external surfaces of Titan's electromagnetic cavity, formed by the ionosphere and a conductive ground or underground surface. However, owing to high losses conferred by the electrical conductivity to Titan's atmosphere, the direct numerical and experimental spectra are decreasing functions of the frequency without resonances or other special forms. The weak atmospheric resonances are extracted from the data measured by the Huygens's sensors after a procedure based on analysis of the late time response is applied to the experimental spectra. The new late time spectra present the appearance expected, with successive peaks and a mean between adjacent resonances of 0.67 kHz, in agreement with the late time TLM results when the Borucki et al. (2006) conductivity profile with aerosols is introduced in the numerical model. This gap in frequency between successive peaks gives an effective optical distance between the ground and the conductive ionosphere of approximately 220 km, considerably higher than the terrestrial one where this distance is around 75 km.

Morente, Juan A.; Portí, Jorge A.; Blanchard, Cedric; Navarro, Enrique A.; Salinas, Alfonso

2009-06-01

367

Electromagnetically induced transparency for a double Fano-profile system  

NASA Astrophysics Data System (ADS)

A ?-like model of atomic levels involving two auto-ionizing states is considered. The levels are irradiated by two external electromagnetic fields, a strong driving and a weak probing ones. The analytical formula for medium susceptibility shows an additional electromagnetically induced transparency window caused by the second auto-ionizing level. Characteristics of both transparency windows are analyzed depending on parameters of auto-ionizing levels and the external driving field. Manipulation of these characteristics seems to be very effective because of their large sensitivity with respect to the parameters involved in the problem. This manipulation becomes even more feasible when considered model is implemented in so-called laser-induced continuum structure.

Bui Dinh, Thuan; Cao Long, Van; Leo?ski, Wies?aw; Pe?ina, Jan

2014-06-01

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

2002-01-01

369

Power Spectra to 1% Accuracy between Dynamical Dark Energy Cosmologies  

E-print Network

For dynamical dark energy cosmologies we carry out a series of N-body gravitational simulations, achieving percent level accuracy in the relative mass power spectra at any redshift. Such accuracy in the power spectrum is necessary for next generation cosmological mass probes. Our matching procedure reproduces the CMB distance to last scattering and delivers subpercent level power spectra at z=0 and z~3. We discuss the physical implications for probing dark energy with surveys of large scale structure.

Matthew J. Francis; Geraint F. Lewis; Eric V. Linder

2007-04-03

370

Theoretical energy level spectra and transition data for 4p{sup 6}4d{sup 2}, 4p{sup 6}4d4f, and 4p{sup 5}4d{sup 3} configurations of W{sup 36+}  

SciTech Connect

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 4p{sup 6}4d{sup 2}, 4p{sup 6}4d4f, and 4p{sup 5}4d{sup 3} configurations of the ion W{sup 36+}. 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., E-mail: Pavelas.Bogdanovicius@tfai.vu.lt; Kisielius, R.

2013-09-15

371

Shuttle Communications and Tracking, Avionics, and Electromagnetic Compatibility  

NASA Technical Reports Server (NTRS)

By definition, electromagnetic compatibility (EMC) is the capability of components, sub-systems, and systems, to operate in their intended electromagnetic environment, within an established margin of safety, and at design levels of performance. Practice of the discipline itself incorporates knowledge of various aspects of applied physics, materials science, and engineering across the board, and includes control and mitigation of undesirable electromagnetic interaction between intentional and unintentional emitters and receivers of radio frequency energy, both within and external to the vehicle; identification and control of the hazards of non-ionizing electromagnetic radiation to personnel, ordnance, and fuels and propellants; and vehicle and system protection from the direct and indirect effects of lightning and various other forms of electrostatic discharge (ESD) threats, such as triboelectrification and plasma charging. EMC is extremely complex and far-reaching, affecting in some degree every aspect of the vehicle s design and operation. The most successful efforts incorporate EMC design features and techniques throughout design and fabrication of the vehicle s structure and components, as well as appropriate operational considerations with regard to electromagnetic threats in the operational environment, from the beginning of the design effort to the end of the life cycle of the manufactured product. This approach yields the highest design performance with the lowest cost and schedule impact.

deSilva, K.; Hwu, Shian; Kindt, Kaylene; Kroll, Quin; Nuss, Ray; Romero, Denise; Schuler, Diana; Sham, Catherine; Scully, Robert

2011-01-01

372

Constraining neutrino electromagnetic properties by germanium detectors  

E-print Network

The electromagnetic properties of neutrinos, which are either trivial or negligible in the context of the Standard Model, can probe new physics and have significant implications in astrophysics and cosmology. The current best direct limits on the neutrino millicharges and magnetic moments are both derived from data taken with germanium detectors with low thresholds at keV levels. In this paper, we discuss in detail a robust, ab initio method: the multiconfiguration relativistic random phase approximation, that enables us to reliably understand the germanium detector response at the sub-keV level, where atomic many-body physics matters. Using existing data with sub-keV thresholds, limits on reactor antineutrino's millicharge, magnetic moment, and charge radius squared are derived. The projected sensitivities for next generation experiments are also given and discussed.

Jiunn-Wei Chen; Hsin-Chang Chi; Keh-Ning Huang; Hau-Bin Li; C. -P. Liu; Lakhwinder Singh; Henry T. Wong; Chih-Liang Wu; Chih-Pan Wu

2014-11-03

373

Un-renormalized classical electromagnetism  

SciTech Connect

This paper follows in the tradition of direct-action versions of electromagnetism having the aim of avoiding a balance of infinities wherein a mechanical mass offsets an infinite electromagnetic mass so as to arrive at a finite observed value. However, the direct-action approach ultimately failed in that respect because its initial exclusion of self-action was later found to be untenable in the relativistic domain. Pursing the same end, this paper examines instead a version of electromagnetism wherein mechanical action is excluded and self-action is retained. It is shown that the resulting theory is effectively interacting due to the presence of infinite forces. A vehicle for the investigation is a pair of classical point charges in a positronium-like arrangement for which the orbits are found to be self-sustaining and naturally quantized.

Ibison, Michael [Institute for Advanced Studies at Austin, 4030 West Braker Lane, Suite 300, Austin, TX 78759 (United States)]. E-mail: ibison@earthtech.org

2006-02-15

374

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

375

Tensor theory of electromagnetic radiometry  

NASA Astrophysics Data System (ADS)

A theory of electromagnetic radiometry is built on the premise that the electromagnetic generalised radiance has a tensor structure, represented by the electric, magnetic and mixed generalised radiance tensors as fundamental quantities. They allow overcoming the limitations due to the scalar generalised radiances, proposed for characterizing stationary random electromagnetic sources. Furthermore, they provide a unified framework for completely describing the energy flux and the states of spatial coherence and polarization of random electromagnetic fields. So, the fundamental quantities of both the scalar generalised radiometry and the classical radiometry or photometry are deduced as particular cases of the tensor theory. A new procedure of analysis of (second-order) correlations, subject to the accomplishment of conservation laws, is also introduced. It reveals that (1) the primary sources of the measurable radiometric quantities associated to the random electromagnetic fields in any states of spatial coherence and polarization are the individual radiators of the radiant source (the correlations of the electric and magnetic field vectors only modulate the contributions given by those radiators) and (2) there are two physical mechanisms for the transport of measurable radiometric quantities by the electromagnetic field, i.e. the propagation of the contributions from individual radiators and their redistribution over each wavefront on propagation. The term redistribution refers to the transfer of portions of the measurable quantity over the wavefronts on propagation, without change its total value over each wavefront. In this context, a physical meaning is given to the negative values of the generalised radiance, which gives new insight about the Poynting's theory of energy transport.

Castaneda, Roman

2007-08-01

376

Scale-Changing Technique for the Electromagnetic Modeling of MEMS-Controlled Planar Phase Shifters  

Microsoft Academic Search

A scale changing approach is proposed for the electromagnetic modeling of phase-shifter elements used in reconfigurable microelectromechanical system (MEMS)-controlled reflectarrays. Based on the partition of the discontinuity plane in planar sub-domains with various scale levels, this technique allows the computation of the phase shift from the simple cascade of networks, each network describing the electromagnetic coupling between two scale levels.

Etienne Perret; Hervé Aubert; Hervé Legay

2006-01-01

377

Study of plasma environments for the integrated Space Station electromagnetic analysis system  

NASA Technical Reports Server (NTRS)

The final report includes an analysis of various plasma effects on the electromagnetic environment of the Space Station Freedom. Effects of arcing are presented. Concerns of control of arcing by a plasma contactor are highlighted. Generation of waves by contaminant ions are studied and amplitude levels of the waves are estimated. Generation of electromagnetic waves by currents in the structure of the space station, driven by motional EMF, is analyzed and the radiation level is estimated.

Singh, Nagendra

1992-01-01

378

Electromagnetic Gun With Commutated Coils  

NASA Technical Reports Server (NTRS)

Proposed electromagnetic gun includes electromagnet coil, turns of which commutated in sequence along barrel. Electrical current fed to two armatures by brushes sliding on bus bars in barrel. Interaction between armature currents and magnetic field from coil produces force accelerating armature, which in turn, pushes on projectile. Commutation scheme chosen so magnetic field approximately coincides and moves with cylindrical region defined by armatures. Scheme has disadvantage of complexity, but in return, enables designer to increase driving magnetic field without increasing armature current. Attainable muzzle velocity increased substantially.

Elliott, David G.

1991-01-01

379

Electromagnetic Models of Extragalactic Jets  

SciTech Connect

Relativistic jets may be confined by large-scale, anisotropic electromagnetic stresses that balance isotropic particle pressure and disordered magnetic field. A class of axisymmetric equilibrium jet models will be described and their radiative properties outlined under simple assumptions. The partition of the jet power between electromagnetic and mechanical forms and the comoving energy density between particles and magnetic field will be discussed. Current carrying jets may be recognized by their polarization patterns. Progress and prospects for measuring this using VLBI and GLAST observations will be summarized.

Lisanti, M.; Blandford, R.; /KIPAC, Menlo Park

2007-10-22

380

Electromagnetic radiation by gravitating bodies  

E-print Network

Gravitating bodies in motion, regardless of their constitution, always produce electromagnetic radiation in the form of photon pairs. This phenomenon is an analog of the radiation caused by the motion of dielectric (or magnetic) bodies. It is a member of a wide class of phenomena named dynamical Casimir effects, and it may be viewed as the squeezing of the electromagnetic vacuum. Production of photon pairs is a purely quantum-mechanical effect. Unfortunately, as we show, the emitted radiation is extremely weak as compared to radiation produced by other mechanisms.

Iwo Bialynicki-Birula; Zofia Bialynicka-Birula

2008-04-06

381

Electromagnetic computations for fusion devices  

SciTech Connect

Among the difficulties in making nuclear fusion a useful energy source, two important ones are producing the magnetic fields needed to drive and confine the plasma, and controlling the eddy currents induced in electrically conducting components by changing fields. All over the world, researchers are developing electromagnetic codes and employing them to compute electromagnetic effects. Ferromagnetic components of a fusion reactor introduce field distortions. Eddy currents are induced in the vacuum vessel, blanket and other torus components of a tokamak when the plasma current disrupts. These eddy currents lead to large forces, and 3-D codes are being developed to study the currents and forces. 35 refs., 6 figs.

Turner, L.R.

1989-09-01

382

A Catalog of Chandra Grating Spectra  

NASA Astrophysics Data System (ADS)

We are developing a Chandra Grating-Data Archive and Catalog to make all grating spectra more visible and accessible to users. We intend to to provide a simple browser interface to analysis-quality standard spectral products (binned spectra and corresponding response files), with the addition of summary graphical products and model-independent flux properties tables. Such products and a browser interface will make it easy for a user to find observations of a particular object, type of object, or type of observation, to quickly assess the quality and potential usefulness of the spectra, and to download the data and responses as a package if desired. We will include LETG data as well as ACIS CC-mode observations. In addition to the data, portable reprocessing scripts, using CXC and other publicly available software which were used to create the archive will also be available to users, facilitating standard or customized reprocessing from download of Level 1 archive data to production of spectra and responses with minimal interaction (analogous to the "psextract" script commonly used for automated imaging spectral extraction). We will add some customized products which may take time, effort, or special expertise to produce. Candidates for such include extended source extractions, crowded field extractions, and aggregate products such as summed Capella or summed Orion-field-objects spectra. Additional content will grow according to user feedback. This catalog builds upon experience with other relevant work, such as the X-Atlas of HETGS spectra (http://cxc.harvard.edu/XATLAS) or the XMM-RGS spectral browser (http://xmm.esac.esa.int/BiRD). It is intended to be a long-term legacy product for Chandra gratings observations. This work was supported by NASA through the Smithsonian Astrophysical Observatory (SAO) contract SV3-73016 for the Chandra X-Ray Center and Science Instruments.

Huenemoerder, David; Nichols, J.; Mitschang, A.; Dewey, D.; Marshall, H.; Nowak, M.; Schulz, N.; Davis, J. E.; Houck, J. C.; Canizares, C.

2008-03-01

383

Magic energies in auger electron spectra  

NASA Astrophysics Data System (ADS)

The Auger electron spectra in ion-solid interaction exhibit "magical" energies. At those energies the electron emission spectrum does not depend on the kinetic energy of the incident ion. We explain this feature in terms of the level broadening of the incoming ion. Furthermore we show that the broadening is proportional to the original ion velocity and we find a new method for extracting the "true" unbroadened spectrum.

Monreal, R.; Apell, S. P.

1993-12-01

384

Development of fatigue loading spectra  

SciTech Connect

The present work on fatigue-loading spectra encompasses the current status of standardized stress-time histories, European approaches to standard loading spectrum development, transport aircraft airframe fatigue test spectra, the TURBISTAN fatigue-loading standard for fighter-aircraft engine disks, an automated procedure for the creation of flight-by-flight spectra, and the development of a wave-action standard history for fatigue testing relevant to tubular structures in the North Sea. Also treated is the use of the TURBISTAN mission spectra to evaluate fatigue crack growth in a rotating disk, fatigue-spectra development for airborne stores, a simplified analysis of fatigue-loading spectra, variable-amplitude load models for fatigue-damage crack growth, the tracking time service histories for multiaxis fatigue problems, and the compilation of procedures for fatigue crack propagation testing under complex load sequences.

Potter, J.M.; Watanabe, R.T.

1989-01-01

385

Development of fatigue loading spectra  

Microsoft Academic Search

The present work on fatigue-loading spectra encompasses the current status of standardized stress-time histories, European approaches to standard loading spectrum development, transport aircraft airframe fatigue test spectra, the TURBISTAN fatigue-loading standard for fighter-aircraft engine disks, an automated procedure for the creation of flight-by-flight spectra, and the development of a wave-action standard history for fatigue testing relevant to tubular structures in

J. M. Potter; R. T. Watanabe

1989-01-01

386

Project no. 516369 Electromagnetic compatibility between rolling stock and  

E-print Network

satisfactorily in its electromagnetic environment without introducing intolerable electromagnetic disturbances to anything in that environment. Electromagnetic interference (EMI): Degradation of the performanceProject no. 516369 Electromagnetic compatibility between rolling stock and rail

Paris-Sud XI, Université de

387

Electrostatic and electromagnetic gyroharmonic emissions due to energetic electrons in magnetospheric plasma  

NASA Technical Reports Server (NTRS)

The paper derives the growth rates and growth lengths of the electrostatic emission for spatially homogeneous and inhomogeneous energetic electrons, and numerically evaluates the growth rate and growth length spectra for several parameter sets representative of magnetospheric plasmas. In addition, the growth rates are derived for the case of electromagnetic emission modeled by the ordinary mode. The numerical results of the electromagnetic and electrostatic cases are compared with observations made by satellites in the earth's magnetosphere. It is concluded that the electrostatic gyroharmonic excitation is possible without the cold composition of plasma which is often postulated in the existing literature.

Curtis, S. A.; Wu, C. S.

1979-01-01

388

Characteristics of electromagnetic interference generated during discharge of Mylar samples. [spacecraft-environment interaction simulation  

NASA Technical Reports Server (NTRS)

This paper discusses the measurements of the electromagnetic interference (EMI) generated during discharges of Mylar samples. The two components of EMI, the conducted emission and the radiated emission, are characterized by the replacement current and the radiated RF spectrum respectively. The measured radiated RF spectra reveal important information on the source of the electromagnetic radiation. The possible sources are the replacement current pulse and the discharged generated plasma. The scaling of the amplitudes of the EMI, as a function of the area of the test sample, is also discussed.

Leung, P. L.

1984-01-01

389

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

390

Electromagnetic effects on geodesic acoustic modes  

SciTech Connect

By using the full electromagnetic drift kinetic equations for electrons and ions, the general dispersion relation for geodesic acoustic modes (GAMs) is derived incorporating the electromagnetic effects. It is shown that m?=?1 harmonic of the GAM mode has a finite electromagnetic component. The electromagnetic corrections appear for finite values of the radial wave numbers and modify the GAM frequency. The effects of plasma pressure ?{sub e}, the safety factor q, and the temperature ratio ? on GAM dispersion are analyzed.

Bashir, M. F., E-mail: frazbashir@yahoo.com [Salam Chair in Physics, G. C. University Lahore, Katchery Road, Lahore 54000 (Pakistan); Department of Physics, G. C. University Lahore, Katchery Road, Lahore 54000 (Pakistan); Smolyakov, A. I. [University of Saskatchewan, 116 Science Place, Saskatoon S7N 5E2 (Canada); Institute of Tokamak Physics, NRC “Kurchatov Institute,” 123182 Moscow (Russian Federation); Elfimov, A. G. [Institute of Physics, University of São Paulo, São Paulo 05508-090 (Brazil); Melnikov, A. V. [Institute of Tokamak Physics, NRC “Kurchatov Institute,” 123182 Moscow (Russian Federation); National Research Nuclear University MEPhI, 115409, Moscow (Russian Federation); Murtaza, G. [Visiting Professor, Department of Physics, Quaid-e-Azam University, Islamabad (Pakistan)

2014-08-15

391

STIMULATED ELECTROMAGNETIC EMISSIONS BY HIGH-FREQUENCY ELECTROMAGNETIC PUMPING OF THE  

E-print Network

STIMULATED ELECTROMAGNETIC EMISSIONS BY HIGH-FREQUENCY ELECTROMAGNETIC PUMPING OF THE IONOSPHERIC.S.A. Abstract. A high frequency electromagnetic pump wave transmitted into the ionospheric plasma from the ground can stimulate electromagnetic radiation with frequencies around that of the ionospher- ically

392

Name of the Presentation Fundamental Properties of Electromagnetic RadiationFundamental Properties of Electromagnetic Radiation  

E-print Network

between the Sun and the Earth. Electromagnetic Spectrum Electromagnetic Spectrum The Sun produces Wavelength in meters (m) Electromagnetic Spectrum and the Photon Energy of Visible Light Visible 10 -12 34/9/2004 1 Name of the Presentation Fundamental Properties of Electromagnetic Radiation

393

IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY, VOL. 55, NO. 2, APRIL 2013 395 Electromagnetic Interference Analysis of  

E-print Network

to electromagnetic interference (EMI) is becoming a critical aspect of signal integrity analysis. For mod- eling in high-speed packages [2]. As a result, effi- cient and accurate electromagnetic interference (EMIIEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY, VOL. 55, NO. 2, APRIL 2013 395 Electromagnetic

Roy, Sourajeet

394

EE335 Electromagnetic Theory II Text: Fundamentals of Applied Electromagnetics 5e  

E-print Network

EE335 Electromagnetic Theory II Text: Fundamentals of Applied Electromagnetics 5e Author: Fawwaz T://www.coe.montana.edu/ee/tjkaiser/EE335/ Office Hours: M 9am, W 10am Prerequisites: EE334 Electromagnetic Theory I or permission from: Exam 1 100 Exam 2 100 Exam 3 100 Term paper 100 Homework 100 Final Exam 200 #12;EE 335 Electromagnetic

Kaiser, Todd J.

395

[Oscillation spectra of metal-porphyrin dication spectra].  

PubMed

Spectra of resonance spontaneous combination scattering (RSCS) of dications of metal--derivatives of tetraphenyl and ethioporphyrine (Ni-TPhP, Cu-TPhP, Cu-EP and VO-EP0 and IR-spectra of absorption of Ni-TPhP and Cu-EP dications were obtained. It was found that transformation of porphyrine neutral molecules into dications is accompanied with the appearance of new absorption bands in IR-spectra analogs of which are in RSCS spectra of dications. In some cases it points to the disturbance of alternative prohibition to oscillative transitions and to structural changes which result in the loss of symmetry centre by the molecule when it is transformed into the dication. A comparison of RSCS spectra of dications and dianions of VO-EP suggests that they have different structure. PMID:7397250

Aleksandrov, I V; Eletski?, N P; Sidorov, A N

1980-01-01

396

Electromagnetic scattering by indented screens  

Microsoft Academic Search

The problem of three dimensional electromagnetic scattering from a perfectly conducting screen with a bounded indentation is formulated as a system of boundary integral equations for the electric current density on the cavity wall and the interface between the cavity and free space. It is shown how the fictitious current density on the interface may be eliminated resulting in an

John S. Asvestas; R. E. Kleinman

1994-01-01

397

The kaon electromagnetic form factor  

E-print Network

We use recent data on K^+ -> pi^+ e^+ e^-, together with known values for the pion form factor, to derive experimental values for the kaon electromagnetic form factor for 0 < q^2 < 0.125 (GeV/c)^2. The results are then compared with the predictions of the Vector Meson Dominance model, which gives a good fit to the experimental results.

J. Lowe; M. D. Scadron

2005-09-28

398

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

399

Using Mathcad in electromagnetics education  

Microsoft Academic Search

Mathcad is an effective learning tool in electromagnetics courses. Use of Mathcad by students in such courses at the University of Denver incorporate four essential ingredients needed for the successful integration of computer aided learning into a curriculum component: (1) involvement by the student in establishing what is to be analyzed by the computer; (2) a general purpose tool rather

Ronald R. DeLyser

1996-01-01

400

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

401

Electromagnetic Properties of Binary Composites  

Microsoft Academic Search

This dissertation contains theoretical studies of electromagnetic properties of three different binary granular composites: Dilute conductor-insulator mixtures with conducting fractal clusters in a long-wavelength limit; dense disordered mixtures of dielectrics in a short-wavelength limit; and optically anisotropic \\

Ingrid Helena Hoffmann Zabel; I. H. H

1992-01-01

402

Winged reentrant electromagnetic combustion chamber  

Microsoft Academic Search

An internal combustion engine combustion chamber suitable for electromagnetic stimulation of combustion which has been improved by the addition of combustion chamber periphery extensions (wings) filled with dielectric material. The wing dimensions and filler dielectric material are chosen to allow for specification of the chamber EM resonant frequency, preferably at a frequency in the UHF range (where low cost DC

M. A. V

1985-01-01

403

Electromagnetic methods in applied geophysics  

Microsoft Academic Search

Applied electromagnetic research in recent years has been influenced by the growing importance of geothermal energy, coal, and permafrost, in addition to the traditional area of minerals. The interest in near-insulators such as coal and ice encouraged development of radars and other VHF-UHF techniques. Interpreting such measurements required reliable physical properties data for those materials over a frequency range of

K. Vozoff

1980-01-01

404

CONFERENCE NOTE: Conference on Precision Electromagnetic Measurements  

NASA Astrophysics Data System (ADS)

The next Conference on Precision Electromagnetic Measurements (CPEM), will be held from 9 to 12 June 1992 at the Centre des Nouvelles Industries et Technologies (CNIT), La Défense, Paris, France. This conference, which is held every two years and whose importance and high level, confirmed by thirty years' experience, are recognized throughout the world, can be considered as a forum in which scientists, metrologists and professionals will have the opportunity to present and compare their research results on fundamental constants, standards and new techniques of precision measurement in the electromagnetic domain. Topics The following topics are regarded as the most appropriate for this conference: realization of units and fundamental constants d.c. a.c. and high voltage time and frequency radio-frequency and microwaves dielectrics, antennas, fields lasers, fibre optics advanced instrumentation, cryoelectronics. There will also be a session on international cooperation. Conference Language The conference language will be English. No translation will be provided. Organizers Société des Electriciens et des Electroniciens (SEE). Bureau National de Métrologie (BNM) Sponsors Institute of Electrical and Electronics Engineers (IEEE) Instrumentation & Measurement Society Union Radio Scientifique Internationale United States National Institute of Standards and Technology Centre National d'Etudes des Télécommunications Mouvement Français pour la Qualité, Section Métrologie Comité National Français de Radioélectricité Scientifique Contact Jean Zara, CPEM 92 publicity, Bureau National de Métrologie, 22, rue Monge, 75005 Paris Tel.: (33) 1 46 34 48 16, Fax: (33) 1 46 34 48 63

1991-01-01

405

Electromagnetically induced interference at superconducting qubits  

E-print Network

We study electromagnetically induced interference at superconducting qubits. The interaction between qubits and electromagnetic fields can provide additional coupling channels to qubit states, leading to quantum interference in a microwave driven qubit. In particular, the interwell relaxation or Rabi oscillation, resulting respectively from the multi- or single-mode interaction, can induce effective crossovers. The environment is modeled by a multi-mode thermal bath, generating the interwell relaxation. Relaxation induced interference, independent of the tunnel coupling, provides deeper understanding to the interaction between the qubits and their environment. It also supplies a useful tool to characterize the relaxation strength as well as the characteristic frequency of the bath. In addition, we demonstrate the relaxation can generate population inversion in a strongly driving two-level system. On the other hand, different from Rabi oscillation, Rabi oscillation induced interference involves more complicated and modulated photon exchange thus offers an alternative means to manipulate the qubit, with more controllable parameters including the strength and position of the tunnel coupling. It also provides a testing ground for exploring nonlinear quantum phenomena and quantum state manipulation, in not only the flux qubit but also the systems with no crossover structure, e.g. phase qubits.

Lingjie Du; Yang Yu

2010-12-14

406

Electromagnetic interference assessment of an ion drive electric propulsion system  

NASA Technical Reports Server (NTRS)

The electromagnetic interference (EMI) form elements of an ion drive electric propulsion system was analyzed, and the effects of EMI interaction with a typical interplanetary spacecraft engineering and scientific subsystems were predicted. SEMCAP, a computerized electromagnetic compatibility assessment code, was used to analyze the impact of EMI noise sources on 65 engineering/telemetry circuits and 48 plasma wave and planetary radio astronomy channels measuring over the range of 100 Hz to 40 MHz in a spacecraft of the Voyager type; manual methods were used to evaluate electrostatics, magnetics, and communications effects. Results indicate that some conducted and radiated spectra are in excess of electromagnetic compatibility specification limits; direct design changes may be required for filtering and shielding of thrust system elements. The worst source of broadband radiated noise appears to be the power processor. The magnetic field necessary to thruster operation is equivalent to about 18 amp-sq m per amp of beam current at right angles to the axis caused by the neutralizer/plume loop.

Whittlesey, A. C.

1979-01-01

407

Electromagnetic coupling and plasmon localization in deterministic aperiodic arrays  

NASA Astrophysics Data System (ADS)

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 case of flat Fourier-transform sequences, which reproduce the behavior of purely random systems to an arbitrary degree of accuracy. Based on the coupled dipole approach (CDA) and finite difference time domain (FDTD) simulations, we study the radiative (long-range) and quasi-static (short-range) electromagnetic coupling in deterministic aperiodic plasmon arrays of metal nanoparticles. In addition, we investigate the local field enhancement and the enhancement scaling in periodic and aperiodic arrays with increasing degree of complexity. We believe that the accurate control of electromagnetic coupling and sub-wavelength field enhancement in deterministic aperiodic environments will enable novel nanodevice applications in areas such as field-enhanced nanosensors, engineered SERS substrates and optical nano-antenna arrays.

Dal Negro, Luca; Feng, Ning-Ning; Gopinath, Ashwin

2008-06-01

408

Electromagnetic Corrections in Staggered Chiral Perturbation Theory  

E-print Network

Electromagnetic Corrections in Staggered Chiral Perturbation Theory C. Bernard and E.D. Freeland perturbation theory including electromagnetism, and discuss the extent to which quenched-photon simulations can-lat]17Nov2010 #12;Electromagnetic Corrections in Staggered Chiral Perturbation Theory E.D. Freeland 1

Bernard, Claude

409

Acousto-electromagnetic Tomography Habib Ammari  

E-print Network

Acousto-electromagnetic Tomography Habib Ammari Emmanuel Bossy Josselin Garnier§ Laurent Seppecher June 28, 2012 Abstract The aim of this paper is to develop a mathematical framework for acousto-electromagnetic tomography and to introduce an efficient reconstruction algorithm. In electromagnetic wave imaging

Garnier, Josselin

410

Studies on a passive electromagnetic damper  

Microsoft Academic Search

The passive electromagnetic damper has the same configuration as that of the electromagnetic bearing, but no sensors and no closed loop control are needed. Its robustness and no-contact structure are its great advantages. When the rotor vibrates, the electromagnetic field intensity in the air gap is altered, then fluctuating currents in the damper coils and eddy currents inside the surface

ZHENG Shui-ying; PAN Xiao-hong; MA Zhen-fei

411

EMG #121471 Electromagnetics, 25:679693, 2005  

E-print Network

Park, Maryland, USA This paper presents the novel use of resistive sheets to reduce electromagnetic that will be discussed in this paper. Significant reduction of electromagnetic leakage is possible by using loading to function as shields of electromagnetic energy. Metallic enclosures are commonly used to reduce emission

Ramahi, Omar

412

Dynamics and Control of Electromagnetic Satellite Formations  

E-print Network

concept that uses superconducting electromagnetic coils to provide forces and torques between differentDynamics and Control of Electromagnetic Satellite Formations Umair Ahsun, David W. Miller June 2007 SSL # 12-07 #12;2 #12;Dynamics and Control of Electromagnetic Satellite Formations by Umair Ahsun B

413

Galerkin Boundary Element Methods for Electromagnetic Scattering  

E-print Network

on boundary integral equations are widely used in the numeri- cal simulation of electromagnetic scatteringGalerkin Boundary Element Methods for Electromagnetic Scattering A. Buffa1 and R. Hiptmair2 1 acous- tic and electromagnetic scattering. The derivation of various boundary integral equations

Buffa, Annalisa

414

OPTIMIZATION USING TAGUCHI METHOD FOR ELECTROMAGNETIC APPLICATIONS  

E-print Network

OPTIMIZATION USING TAGUCHI METHOD FOR ELECTROMAGNETIC APPLICATIONS Wei-Chung Weng, Fan Yang, Veysel electromagnetic optimization technique based on Taguchi method. Using the concept of the orthogonal array (OA. This study uses a new electromagnetic optimization technique, Taguchi method [1], to design a linear antenna

Elsherbeni, Atef Z.

415

Localization of Classical Waves II: Electromagnetic Waves.  

E-print Network

of electromagnetic waves. This phenomenon arises from coherent multiple scattering and interference, when the scaleLocalization of Classical Waves II: Electromagnetic Waves. Alexander Figotin \\Lambda Department We consider electromagnetic waves in a medium described by a position dependent dielectric constant

416

611: Electromagnetic Theory Problem Sheet 5  

E-print Network

611: Electromagnetic Theory Problem Sheet 5 (1a) Show that the energy-momentum tensor for the electromagnetic field is tracefree, i.e. Tµ µ = 0. What would happen, in a spacetime dimension d = 4? (Assume) Show that the energy-momentum tensor for the electromagnetic field can be written as Tµ = 1 8 (Fµ F

Pope, Christopher

417

611: Electromagnetic Theory Problem Sheet 5  

E-print Network

611: Electromagnetic Theory Problem Sheet 5 (1a) The Null Energy Condition on an energy = (k, 0, 0, k), show that the energy-momentum tensor Tµ = 1 4 Fµ F - 1 4µ F F (1) for electromagnetism if the equality kµ k Tµ = 0 is attained. (2) Show that the energy-momentum tensor for electromagnetism can

Pope, Christopher

418

Physics 4: Introductory Physics Electromagnetism and Light  

E-print Network

Physics 4: Introductory Physics Electromagnetism and Light Professor Jeffrey D. Richman Department: Electromagnetism and Light Welcome to Physics 4! What is your goal in life? If it is to become an engineer or to pursue a career in science, this is a key class for you. Understanding electromagnetism and light

Fygenson, Deborah Kuchnir

419

611: Electromagnetic Theory Problem Sheet 6  

E-print Network

611: Electromagnetic Theory Problem Sheet 6 (1) Consider the expression for the electric field due · dS over a spherical surface that encloses the moving charge. (2a) Consider an electromagnetic wave density and the Poynting vector. (2c) Repeat the steps in (2a) and (2b) for an electromagnetic wave

Pope, Christopher

420

Course Outline Physics 433: Electromagnetism II  

E-print Network

Course Outline Physics 433: Electromagnetism II Spring 2014 Prof. Keun Hyuk "Ken" Ahn 483 Tiernan of this course is on the elementary concepts of electromagnetic fields. Upon completion of the course, students are expected to be capable of using the Maxwell equations to calculate simple electromagnetic problems, ranging

421

Electromagnetics from Simulation to Optimal Design  

E-print Network

1 Electromagnetics from Simulation to Optimal Design Christian Hafner Laboratory for Electromagnetic Fields and Microwave Electronics (IFH) ETH Zurich (Switzerland) Lab: http://www.ifh.ee.ethz.ch COG 23, 2013 #12;2 IFH courses · Advanced engineering electromagnetics (Leuchtmann, start spring 2014

Lang, Annika

422

Electromagnetic Interrogation of Dielectric Materials 1  

E-print Network

Electromagnetic Interrogation of Dielectric Materials 1 H.T. Banks M.W. Buksas Center for Research grant P200A40730. #12; Abstract We investigate time domain based electromagnetic inverse problems electromagnetic phenomenon. For our purposes, we categorize the materials and the models employed to describe them

423

611: Electromagnetic Theory Problem Sheet 5  

E-print Network

611: Electromagnetic Theory Problem Sheet 5 (1) Consider the expression for the electric field due · dS over a spherical surface that encloses the moving charge. (2a) Consider an electromagnetic wave density and the Poynting vector. (2c) Repeat the steps in (2a) and (2b) for an electromagnetic wave

Pope, Christopher

424

Electromagnetic Formation Flight of Satellite Arrays  

E-print Network

Electromagnetic Formation Flight of Satellite Arrays Daniel W. Kwon and David W. Miller February 2005 SSL # 2-05 #12;#12;Electromagnetic Formation Flight of Satellite Arrays By DANIEL W. KWON S;#12;Electromagnetic Formation Flight of Satellite Arrays by DANIEL W. KWON Submitted to the Department of Aeronautics

425

Geant4 low energy electromagnetic physics  

Microsoft Academic Search

The Geant4 simulation toolkit includes a specialised package, implementing a precise treatment of electromagnetic interactions of particles with matter below 1 keV. The Geant4 low energy electromagnetic package provides a variety of models describing the electromagnetic processes of electrons and positrons, photons, charged hadrons and ions, taking into account detailed features, such as atomic shell effects and charge dependence. Those

S. Chauvie; S. Guatelli; V. Ivanchenko; F. Longo; A. Mantero; B. Mascialino; P. Nieminen; L. Pandola; S. Parlati; L. Peralta; M. G. Pia; M. Piergentili; P. Rodrigues; S. Saliceti; A. Trindade

2004-01-01

426

A technology that squeezes electromagnetic waves  

E-print Network

A technology that squeezes electromagnetic waves into minuscule structures may yield a new and manipulate visible light and other electromagnetic waves--could someday replace electronic circuits in micro match those of the electromagnetic field outside the metal. The result is the generation of surface

Atwater, Harry

427

221A Lecture Notes Electromagnetic Couplings  

E-print Network

221A Lecture Notes Electromagnetic Couplings 1 Classical Mechanics The coupling of the electromagnetic field with a charged point particle of charge e is given by a term in the action (MKSA system.1 Electromagnetic field's story One way to introduce the coupling Eq. (1) is by starting with Maxwell's equations

Murayama, Hitoshi

428

COPYRIGHT NOTICE: Robert J. Gould: Electromagnetic Processes  

E-print Network

COPYRIGHT NOTICE: Robert J. Gould: Electromagnetic Processes is published by Princeton University rules) for the calculation of rates of electromagnetic processes. Instead of trying to "derive of electromagnetic radiation begin to be considered seriously.1 In 1922, the par ticle character of the photon

Landweber, Laura

429

Some Student Conceptions of Electromagnetic Induction  

ERIC Educational Resources Information Center

Introductory electromagnetism is a central part of undergraduate physics. Although there has been some research into student conceptions of electromagnetism, studies have been sparse and separated. This study sought to explore second year physics students' conceptions of electromagnetism, to investigate to what extent the results from the present…

Thong, Wai Meng; Gunstone, Richard

2008-01-01

430

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

431

Electromagnetics for Detecting Shallow Tunnels  

NASA Astrophysics Data System (ADS)

Detecting tunnels by geophysical means, even very shallow ones, has been difficult, to say the least. Despite heavy R&D funding from the military since the early 70s, geophysicists have not produced tools that are simple and practical enough to meet the military needs. The initial interest and R&D funding on the subject perhaps started with the Vietcong tunnels in the 60s. Tunnels in the Korean DMZ, first found in the mid 70s, sharply escalated the R&D spending. During the 90s, covert tunnels along the US-Mexico border have kept the topic alive but at a minimal funding level. Most recent interest appears to be in the terrorism-related shallow tunnels, more or less anywhere in the regions of conflict. Despite the longstanding effort in the geophysical community under heavy public funding, there is a dearth of success stories where geophysicists can actually claim to have found hitherto unknown tunnels. For instance, geophysics has not discovered a single tunnel in Vietnam or in Korea! All tunnels across the Korean DMZ were found from human intelligence. The same is true to all illicit tunnels found along the southwestern border. The tunnels under discussion are clandestine, which implies that the people who built them do not wish others to succeed in finding them. The place around the tunnel, therefore, may not be the friendliest venue for surveyors to linger around. The situation requires tools that are fast, little noticeable, and hardly intrusive. Many geophysical sensors that require ground contacts, such as geophones and electrodes that are connected by a myriad of cables, may not be ideal in this situation. On the other hand, a sensor that can be carried by vehicle without stopping, and is nothing obviously noticeable to bystanders, could be much more acceptable. Working at unfriendly environment also requires forgoing our usual practices where we collect data leisurely and make pretty maps later. To be useful, geophysical tools must be able to process observed data and translate them into actionable results. They may in forms of audio (similar to the beeper of a landmine detector), strip chart, or even a 2D graphic display on a computer screen. In short, the tool must be able to declare a contact, audibly or graphically, in real time or shortly thereafter. In summary, we have two questions here. The first one is if any of the available geophysical tools can detect tunnels. If the answer is yes, then the next question is if any of them are able to perform fast in an unfriendly environment. Electromagnetic sensors may be able to meet the operational requirements: under what circumstances it can find tunnels would be another outstanding question.

Won, I.

2006-05-01

432

Two components in meteor spectra  

Microsoft Academic Search

Through an analysis of fireball spectra it was found that meteor heads consist of two parts with quite different temperatures. The spectra of both parts can be fitted with a simple thermal equilibrium model. The temperature of the main spectrum is about 4000 K, and that of the second spectrum is about 10,000 K. There is little evidence for a

Jiri Borovicka

1994-01-01

433

Inclusive jet spectra in p-Pb collisions at ALICE  

NASA Astrophysics Data System (ADS)

Jet suppression has been observed in central heavy ion collisions. This suppression is attributed to partonic energy loss in the Quark Gluon Plasma (QGP) formed in such collisions. However, this measurement is influenced by all stages of the collision. It is expected that in p-Pb collisions similar initial conditions occur as in Pb-Pb collisions without creating a QGP, allowing modification to the jet spectra due to cold nuclear matter effects to be quantified. Inclusive jet spectra in p-Pb collisions at ?{sNN} = 5.02 TeV measured by ALICE are presented. Jets are reconstructed via the anti-kT algorithm with different resolution parameters by combining charged tracks measured in the ALICE tracking system with the neutral energy deposited in the electromagnetic calorimeter. The jet spectra can be used to determine a nuclear modification factor RpPb while the jet profile in p-Pb is studied by dividing spectra measured with different resolution parameters and comparing to the same ratio measured in pp collisions.

Connors, Megan

2014-11-01

434

Inclusive Jet Spectra in p-Pb Collisions at ALICE  

E-print Network

Jet suppression has been observed in central heavy ion collisions. This suppression is attributed to partonic energy loss in the Quark Gluon Plasma (QGP) formed in such collisions. However, this measurement is influenced by all stages of the collision. It is expected that in p-Pb collisions similar initial conditions occur as in Pb-Pb collisions without creating a QGP, allowing modification to the jet spectra due to cold nuclear matter effects to be quantified. Inclusive jet spectra in p-Pb collisions at $\\sqrt{s_{\\rm NN}} = 5.02$ TeV measured by ALICE are presented. Jets are reconstructed via the anti-k$_{\\rm T}$ algorithm with different resolution parameters by combining charged tracks measured in the ALICE tracking system with the neutral energy deposited in the electromagnetic calorimeter. The jet spectra can be used to determine a nuclear modification factor $R_{\\rm pPb}$ while the jet profile in p-Pb is studied by dividing spectra measured with different resolution parameters and comparing to the same ratio measured in pp collisions.

Megan Connors; for the ALICE Collaboration

2014-09-11

435

Some Wave Equations for Electromagnetism and Gravitation  

E-print Network

The paper studies the inferences of wave equations for electromagnetic fields when there are gravitational fields at the same time. In the description with the algebra of octonions, the inferences of wave equations are identical with that in conventional electromagnetic theory with vector terminology. By means of the octonion exponential function, we can draw out that the electromagnetic waves are transverse waves in a vacuum, and rephrase the law of reflection, Snell's law, Fresnel formula, and total internal reflection etc. The study claims that the theoretical results of wave equations for electromagnetic strength keep unchanged in the case for coexistence of gravitational and electromagnetic fields. Meanwhile the electric and magnetic components of electromagnetic waves can not be determined simultaneously in electromagnetic fields.

Zi-Hua Weng

2010-08-11

436

PT symmetry via electromagnetically induced transparency.  

PubMed

We propose a scheme to realize parity-time (PT) symmetry via electromagnetically induced transparency (EIT). The system we consider is an ensemble of cold four-level atoms with an EIT core. We show that the cross-phase modulation contributed by an assisted field, the optical lattice potential provided by a far-detuned laser field, and the optical gain resulted from an incoherent pumping can be used to construct a PT-symmetric complex optical potential for probe field propagation in a controllable way. Comparing with previous study, the present scheme uses only a single atomic species and hence is easy for the physical realization of PT-symmetric Hamiltonian via atomic coherence. PMID:24514800

Li, Hui-Jun; Dou, Jian-Peng; Huang, Guoxiang

2013-12-30

437

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

438

Research instrumentation for tornado electromagnetics emissions detection  

NASA Technical Reports Server (NTRS)

Instrumentation for receiving, processing, and recording HF/VHF electromagnetic emissions from severe weather activity is described. Both airborne and ground-based instrumentation units are described on system and subsystem levels. Design considerations, design decisions, and the rationale behind the decisions are given. Performance characteristics are summarized and recommendations for improvements are given. The objectives, procedures, and test results of the following are presented: (1) airborne flight test in the Midwest U.S.A. (Spring 1975) and at the Kennedy Space Center, Florida (Summer 1975); (2) ground-based data collected in North Georgia (Summer/Fall 1975); and (3) airborne flight test in the Midwest (late Spring 1976) and at the Kennedy Space Center, Florida (Summer 1976). The Midwest tests concentrated on severe weather with tornadic activity; the Florida and Georgia tests monitored air mass convective thunderstorm characteristics. Supporting ground truth data from weather radars and sferics DF nets are described.

Jenkins, H. H.; Wilson, C. S.

1977-01-01

439

Benchmarking statistical averaging of spectra with HULLAC  

NASA Astrophysics Data System (ADS)

Knowledge of radiative properties of hot plasmas is important for ICF, astrophysics, etc When mid-Z or high-Z elements are present, the spectra are so complex that one commonly uses statistically averaged description of atomic systems [1]. In a recent experiment on Fe[2], performed under controlled conditions, high resolution transmission spectra were obtained. The new version of HULLAC [3] allows the use of the same model with different levels of details/averaging. We will take advantage of this feature to check the effect of averaging with comparison with experiment. [1] A Bar-Shalom, J Oreg, and M Klapisch, J. Quant. Spectros. Rad. Transf. 65, 43 (2000). [2] J. E. Bailey, G. A. Rochau, C. A. Iglesias et al., Phys. Rev. Lett. 99, 265002-4 (2007). [3]. M. Klapisch, M. Busquet, and A. Bar-Shalom, AIP Conference Proceedings 926, 206-15 (2007).

Klapisch, Marcel; Busquet, Michel

2008-11-01

440

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

2013-07-12

441

Electromagnetic instability in holographic QCD  

E-print Network

Using the AdS/CFT correspondence, we calculate the vacuum decay rate for the Schwinger effect in confining large $N_{c}$ gauge theories. The instability is induced by the quark antiquark pair creation triggered by strong electromagnetic fields. The decay rate is obtained as the imaginary part of the Euler-Heisenberg effective Lagrangian evaluated from the D-brane action with a constant electromagnetic field in holographic QCD models such as the Sakai-Sugimoto model and the deformed Sakai-Sugimoto model. The decay rate is found to increase with the magnetic field parallel to the electric field, while it decreases with the magnetic field perpendicular to the electric field. We discuss generic features of a critical electric field as a function of the magnetic field and the QCD string tension in the Sakai-Sugimoto model.

Hashimoto, Koji; Sonoda, Akihiko

2014-01-01

442

Teaching Electromagnetism Using Advanced Technologies  

NSDL National Science Digital Library

Michael Faraday was the first to realize that the shape of electromagnetic field lines is extraordinarily expressive of their dynamical effects. We can understand intuitively many things about the forces transmitted by the fields by looking at the topology of the field lines. This is especially true when the field lines are animated. This NSF-funded site has many examples of EM field lines.

Belcher, John

2003-10-10

443

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

444

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

445

Laminated electromagnetic pump stator core  

DOEpatents

A stator core for an electromagnetic pump includes a plurality of circumferentially abutting tapered laminations extending radially outwardly from a centerline axis to collectively define a radially inner bore and a radially outer circumference. Each of the laminations includes radially inner and outer edges and has a thickness increasing from the inner edge toward the outer edge to provide a substantially continuous path adjacent the circumference. This pump is used in nuclear fission reactors. 19 figs.

Fanning, A.W.

1995-08-08

446

Dynamical Bridges: The Electromagnetic Case  

NASA Astrophysics Data System (ADS)

We present the main line of the Dynamical Bridge method applied to electromagnetic (EM) fields. In this framework, we show the equivalence between the Born- Infeld theory written in a given curved space to the Maxwell's one written in the flat space. In the limit of weak EM fields, we obtain a geometrical contribution to the anomalous magnetic moment of the leptons and, finally, we compare it with experimental data.

Bittencourt, Eduardo

2014-12-01

447

Dark Energy, Gravitation and Electromagnetism  

E-print Network

In the context of the fact that the existence of dark energy causing the accelerated expansion of the universe has been confirmed by the WMAP and the Sloan Digital Sky Survey, we re-examine gravitation itself, starting with the formulation of Sakharov and show that it is possible to obtain gravitation in terms of the electromagnetic charge of elementary particles, once the ZPF and its effects at the Compton scale are taken into account.

B. G. Sidharth

2004-01-08

448

Electromagnetic Activation of Capillary Switches  

Microsoft Academic Search

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

Bernie Malouin; Rohan Dayal; Leila Parsa; Amir Hirsa

2008-01-01

449

Analytical Prediction of Electromagnetic Environments  

Microsoft Academic Search

The problem of transmitting digital data through electromagnetic environments of high ambient-pulse density is one of growing concern. The appearance of pulsed radar in the lO-Mw range, and sensitive receivers in the - 100-dbm range, will aggravate this situation. This paper discusses three efforts made by the government to predict the status of future environments. In all cases, the basic

W. H. TETLEYt

1961-01-01

450

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

451

Laminated electromagnetic pump stator core  

SciTech Connect

A stator core for an electromagnetic pump includes a plurality of circumferentially abutting tapered laminations extending radially outwardly from a centerline axis to collectively define a radially inner bore and a radially outer circumference. Each of the laminations includes radially inner and outer edges and has a thickness increasing from the inner edge toward the outer edge to provide a substantially continuous path adjacent the circumference.

Fanning, Alan W. (San Jose, CA)

1995-01-01

452

Electromagnetically induced spatial light modulation  

E-print Network

We theoretically report that, utilizing electromagnetically induced transparency (EIT), the transverse spatial properties of weak probe fields can be fast modulated by using optical patterns (e.g. images) with desired intensity distributions in the coupling fields. Consequently, EIT systems can function as high-speed optically addressed spatial light modulators. To exemplify our proposal, we indicate the generation and manipulation of Laguerre-Gaussian beams based on either phase or amplitude modulation in hot vapor EIT systems.

L. Zhao; T. Wang; S. F. Yelin

2008-12-14

453

Wind measurements by electromagnetic probes  

NASA Technical Reports Server (NTRS)

The emerging technology of electromagnetic probing of the atmosphere to measure winds used in a space vehicle ascent winds load calculations is presented. The frequency range, altitude, and resolution for the following probes are presented: lidars, microwave radars, and clear-air Doppler radars (popularly known as wind profilers). The electromagnetic probing of the atmosphere by clear-air radars and lasers is the new technology to supplement balloon-borne wind sensors used to determine ascent wind loads of space vehicles. The electromagnetic probes measure the wind velocity using the Doppler effect. This is the radar technology used in MSFC's Radar Wind Profiler, and is similar to the technology used in conventional Doppler systems except that the frequency is generally lower, antenna is bigger, and dwell time much longer. Designed for unattended and automated instrumentation in providing measurements of the wind in the troposphere, the profiler employs Doppler radar technology and is currently being put in operation at NASA Kennedy Space Center, Florida.

Susko, Michael

1988-01-01

454

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

455

GSM base station electromagnetic radiation and oxidative stress in rats.  

PubMed

The ever increasing use of cellular phones and the increasing number of associated base stations are becoming a widespread source of nonionizing electromagnetic radiation. Some biological effects are likely to occur even at low-level EM fields. In this study, a gigahertz transverse electromagnetic (GTEM) cell was used as an exposure environment for plane wave conditions of far-field free space EM field propagation at the GSM base transceiver station (BTS) frequency of 945 MHz, and effects on oxidative stress in rats were investigated. When EM fields at a power density of 3.67 W/m2 (specific absorption rate = 11.3 mW/kg), which is well below current exposure limits, were applied, MDA (malondialdehyde) level was found to increase and GSH (reduced glutathione) concentration was found to decrease significantly (p < 0.0001). Additionally, there was a less significant (p = 0.0190) increase in SOD (superoxide dismutase) activity under EM exposure. PMID:16954120

Yurekli, Ali Ihsan; Ozkan, Mehmed; Kalkan, Tunaya; Saybasili, Hale; Tuncel, Handan; Atukeren, Pinar; Gumustas, Koray; Seker, Selim

2006-01-01

456

Propagation of terahertz electromagnetic wave in plasma with inhomogeneous collision frequency  

SciTech Connect

In this paper, we investigate the absorption spectra of terahertz electromagnetic wave in plasma with inhomogeneous collision frequency. Profiles are introduced to describe the non-uniformity of collision frequency. It is interesting to find that when the plasma is collision frequency inhomogeneous, the absorption spectrum would decreases faster than that in uniform plasma. And the rate of decreasing would be different when the profile changes. Two parameters are set up to predict how the profiles affect the absorption spectra. Furthermore, the effects of electron density are also considered.

Tian, Yuan; Han, YiPing; Ling, YingJie [School of Physics and Optoelectronic Engineering, Xidian University, Xi'an 710071 (China)] [School of Physics and Optoelectronic Engineering, Xidian University, Xi'an 710071 (China); Ai, Xia [National Laboratory of Science and Technology on Antennas and Microwaves Xidian University, Xi'an 710071 (China)] [National Laboratory of Science and Technology on Antennas and Microwaves Xidian University, Xi'an 710071 (China)

2014-02-15

457

Interaction of electromagnetic and acoustic waves in a stochastic atmosphere  

NASA Technical Reports Server (NTRS)

In the Stanford radio acoustic sounding system (RASS) an electromagnetic signal is made to scatter from a moving acoustic pulse train. Under a Bragg-scatter condition maximum electromagnetic scattering occurs. The scattered radio signal contains temperature and wind information as a function of the acoustic-pulse position. In this investigation RASS performance is assessed in an atmosphere characterized by the presence of turbulence and mean atmospheric parameters. The only assumption made is that the electromagnetic wave is not affected by stochastic perturbations in the atmosphere. It is concluded that the received radio signal depends strongly on the intensity of turbulence for altitudes of the acoustic pulse greater than the coherence length of propagation. The effect of mean vertical wind and mean temperature on the strength of the received signal is also demonstrated to be insignificant. Mean horizontal winds, however, shift the focus of the reflected electromagnetic energy from its origin, resulting in a decrease in received signal level when a monostatic radio-frequency (RF) system is used. For a bistatic radar configuration with space diversified receiving antennas, the shifting of the acoustic pulse makes possible the remote measurement of the horizontal wind component.

Bhatnagar, N.; Peterson, A. M.

1979-01-01

458

Elemental Absorption and Emission Spectra  

NSDL National Science Digital Library

This applet displays the periodic table of elements. Clicking on an element will show its line spectrum (as a neutral species). Both absorption and emission spectra can be observed. The cursor can be used to measure the wavelengths.

459

Detuned Electromagnetically Induced Transparency in an $N$-type Atom  

E-print Network

The electromagnetically induced transparency (EIT) in an $N$ configuration is studied under both resonant and off-resonant conditions. In a certain off-resonant condition the dark state of the four level system, which is almost the same as the resonant dark state in $\\Lambda$ configuration, is rebuilt. The actual system with damping is examined using optical Bloch equation, both numerically and analytically. Based on this detuned dark state, some new applications with frequency shifts can be realized.

Bin Luo; Xiao Li; Hong Guo

2006-01-23

460

Electromagnetic gyrokinetic PIC simulation with an adjustable control variates method  

Microsoft Academic Search

In the last decade, it became clear that electromagnetic (gyro)kinetic particle-in-cell (PIC) simulations are very demanding in respect to numerical methods and the number of markers used. The Monte Carlo discretization of the gyrokinetic equations leads to a severe signal-to-noise problem: the statistical representation of the physically irrelevant but numerically dominant adiabatic current causing a high statistical noise level. The

R. Hatzky; A. Könies; A. Mishchenko

2007-01-01

461

Spectra ID of recent SN  

NASA Astrophysics Data System (ADS)

P. Challis, Harvard-Smithsonian Center for Astrophysics (CfA), on behalf of the CfA Supernova Group, report spectra (range 320-860 nm) of various SN obtained during Dec. 24-27 UT by P. Challis, S. Gottilla (MMTO.org), and E. Marin (MMTO.org) with the MMT 6.5-m telescope (+ Blue Channel). Cross-correlation with a library of supernova spectra using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J.

Challis, Peter

2013-12-01

462

Electromagnetic Emission by a System of Nonequilibrium Magnons in a Ferrite  

Microsoft Academic Search

Spectra of electromagnetic emission of frequencies ~= omega_i,2omega i and 3omega i, where omega i is the bottom ofthe spin-wave band have been studied in yttrium iron garnetat temperatures of liquid nitrogen and liquid helium.The spin-wave system was strongly excited by parallel pumpingwith microwaves of frequency omega p > 2 omega i.Line shapes and frequency shifts of the emission depend

Alexandr Yu. Taranenko; Michinobu Mino; Hitoshi Yamazaki; Vladimir L. Safonov

1996-01-01

463

Scale Changing Technique for the Electromagnetic Modeling of Planar Self-Similar Structures  

Microsoft Academic Search

A scale changing approach is proposed for analyzing the electromagnetic scattering from discrete self-similar (e.g., log-periodic or pre-fractal) planar structures. Such structures present metallic patterns at multiple scale levels and are viewed here as the superposition of multiple domains enclosed with appropriate boundary conditions. In each domain higher-order modes provide the accurate local description of the electromagnetic fields while lower-order

Damien Voyer; Hervé Aubert; Jacques David

2006-01-01

464

Electromagnetic instability and stopping power of plasma for relativistic electron beams  

Microsoft Academic Search

The stopping power of a plasma for a relativistic electron beam (REB) is derived by taking a Weibel-type electromagnetic instability into account in a collisionless plasma. A quasi-linear theory is developed to derive the stopping power of the plasma due to the electromagnetic instability. The wave-particle interaction by use of the renormalization theory leads to a saturation level of instability.

Toshio Okada; Keishiro Niu

1980-01-01

465

One-electron atoms in Schwarzschild Universe Bare and electromagnetically dressed cases  

E-print Network

The quantum mechanics of one-electron atoms in presence of external electromagnetic fields is considered within Weber's framework. The results by the earlier studies are extended in the sense that for given source and field configurations the changes of the electromagnetic potentials due to the curved background are included. The formulation is specialized to the case with Schwarzschild background. The first corrections to the energy levels for bare atom and Zeeman/Stark effects are calculated, exhibiting possible changes in meaningful orders.

Abolfazl Jafari

2014-02-11

466

One-electron atoms in Schwarzschild Universe Bare and electromagnetically dressed cases  

E-print Network

The quantum mechanics of one-electron atoms in presence of external electromagnetic fields is considered within Weber's framework. The results by the earlier studies are extended in the sense that for given source and field configurations the changes of the electromagnetic potentials due to the curved background are included. The formulation is specialized to the case with Schwarzschild background. The first corrections to the energy levels for bare atom and Zeeman/Stark effects are calculated, exhibiting possible changes in meaningful orders.

Jafari, Abolfazl

2014-01-01

467

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

468

Enhancing the resolution of gpr spectra for pavement engineering applications  

NASA Astrophysics Data System (ADS)

Ground Penetrating Radar (GPR) is a geophysical method that uses radar pulses to image the subsurface. This non-destructive method uses electromagnetic radiation and detects the reflected signals from subsurface structures. It can detect objects, changes in material, and voids and cracks. GPR has many applications in a number of fields. In the field of civil engineering one of the most advanced technologies used for road pavement monitoring is based on the deployment of advanced GPR systems. One of the most relevant causes of road pavement damage is often referable to water intrusion in structural layers. In this context, GPR has been recently proposed as a method to estimate moisture content in a porous medium without preventive calibration. Hence, the development of methods to obtain an estimate of the moisture content is a crucial research field involving economic, social and strategic aspects in road safety for a great number of public and private Agencies. In particular, a recent new approach was proposed to estimate moisture content in a porous medium basing on the theory of Rayleigh scattering, showing a shift of the frequency peak of the GPR spectrum towards lower frequencies as the moisture content increases in the soil. The weakness characterizing this approach is represented by the needs of high resolution signals, whereas GPR spectra are affected by low resolution. Hence, the rising requirement for high resolution leads to specific demands for improved prediction methods. Recently, a new technique combining the response of the conventional fast Fourier transform (FFT, well known for its high-precision receiving signal level) with that of the MUSIC (multiple signal classification) algorithm, well known for its super-resolution capacity has been proposed. This combined method has been proved to obtain a high precision level in quantifying the shift of the frequency peak of the GPR spectrum. This combined method can perform a reliable coarse estimate of the (abscissa of the) frequency peak. Unfortunately, whereas resolution affecting the GPR spectra has been enhanced, we still need a sensible increasing of the moisture content to appreciate a visible frequency shift. Hence, sub-sample resolution techniques are needed to obtain a resolution better than the sample period. Addressing some of these issues, this work proposes a sub-sample resolution technique exploiting a fast parabolic interpolator, running on three samples of the GPR spectrum in the neighborhood of the frequency peak (i.e. the coarse estimation). More in details, the new detector searches for the (abscissa of the) vertex of the parabola fitted over three GPR samples: the coarse estimate of the frequency peak, and one sample before and after this estimation. The rationale behind the new fast parabolic approach is as follows. We expect the method to obtain a finer estimation of the (abscissa of the) frequency peak because we are now interpolating a parabola in the neighborhood of the same maximum (i.e the coarse estimate), but with a narrow variance thus increasing the estimation accuracy. No noteworthy increase of computational complexity and processing throughput is required to implement the new approach. In fact, near the totality of the amount of the required computation is due to the former stage (i.e. FFT and/or MUSIC implementation to evaluate the coarse estimate of the frequency peak), and the latter logic (i.e. the interpolation function) is negligible from implementation and computational point of view. Experimental results confirm the effectiveness of the proposed approach to evidence and quantify moisture content in soil. In fact, the proposed sub-sample super resolution technique can resolve a frequency shift in the GPR spectrum even for a corresponding amount of moisture less than 2-3%.

Benedetto, F.; Benedetto, A.

2012-04-01

469

Stability of miniature electromagnetic tracking systems  

NASA Astrophysics Data System (ADS)

This study aims at a comparative evaluation of two recently introduced electromagnetic tracking systems under reproducible simulated operating-room (OR) conditions: the recently launched Medtronic StealthStation™ Treon-EM™ and the NDI Aurora™. We investigate if and to what extent these systems provide improved performance and stability in the presence of surgical instruments as possible sources of distortions compared with earlier reports on electromagnetic tracking technology. To investigate possible distortions under pseudo-realistic OR conditions, a large Langenbeck hook, a dental drill with its handle and an ultrasonic (US) scanhead are fixed on a special measurement rack at variable distances from the navigation sensor. The position measurements made by the Treon-EM™ were least affected by the presence of the instruments. The lengths of the mean deviation vectors were 0.21 mm for the Langenbeck hook, 0.23 mm for the drill with handle and 0.56 mm for the US scanhead. The Aurora™ was influenced by the three sources of distortion to a higher degree. A mean deviation vector of 1.44 mm length was observed in the vicinity of the Langenbeck hook, 0.53 mm length with the drill and 2.37 mm due to the US scanhead. The maximum of the root mean squared error (RMSE) for all coordinates in the presence of the Langenbeck hook was 0.3 mm for the Treon™ and 2.1 mm for the Aurora™ the drill caused a maximum RMSE of 0.2 mm with the Treon™ and 1.2 mm with the Aurora™. In the presence of the US scanhead, the maximum RMSE was 1.4 mm for the Treon™ and 5.1 mm for the Aurora™. The new generation of electromagnetic tracking systems has significantly improved compared to common systems that were available in the middle of the 1990s and has reached a high level of technical development. We conclude that, in general, both systems are suitable for routine clinical application.

Schicho, Kurt; Figl, Michael; Donat, Markus; Birkfellner, Wolfgang; Seemann, Rudolf; Wagner, Arne; Bergmann, Helmar; Ewers, Rolf

2005-05-01

470

Lamb shift in non-degenerate energy level systems placed between two  

E-print Network

-degenerate energy levels, put in the electromagnetic environment provided by two infinite parallel conducting plates as the strongest experimental supports for the quantization of the electromagnetic field. In free space, the ground state of the quantized electromagnetic field is the siege of quan- tum fluctuations which generate

Boyer, Edmond

471

Recombination spectra of Helium-Like Ions  

E-print Network

We calculate the recombination spectra of the He-like ions He~I, C~V, N~VI, O~VII, Ne~IX, Mg~XI, Si~XIII, S~XV, Ar~XVII, Ca~XIX, and Fe~XXV. We include the following physical processes: radiative recombination, dielectronic recombination, three-body recombination, electron impact ionization, and collisional excitation by electrons, protons, and $\\alpha$-particles. The calculations account for the effects of lowering of the continuum at high densities and high density corrections to dielectronic recombination. Then we construct models for He-like ions for fast computation of their spectra. Every model includes 29 bound levels up to n=5 and 6 doubly excited levels that account for the most important satellite lines. The models are constructed in a way that allows for proper approach to LTE under appropriate conditions. These models can simultaneously solve for the H/He-like ionization balance in photoionized or collisionally ionized plasmas and compute emission spectra including the combined effects of radiative and dielectronic recombination, collisional excitation, photoionization from excited levels, fluorescence, and line trapping. The models can be used for any temperature between 100 and $10^9$K and electron densities of up to $10^{18}$ \\cm3. The models can be easily used within spectral modeling codes or as stand-alone tools for spectral analysis. We present comparisons between the results of the present models and previous work. Significant differences are found between the present effective recombination rate coefficients to the $n=2$ and those of previous estimates. Later, we study various emission line ratio diagnostics under collisional ionization and photoionized conditions.

M. A. Bautista; T. R. Kallman

2000-06-26

472

An omnidirectional electromagnetic absorber made of metamaterials  

NASA Astrophysics Data System (ADS)

In a recent theoretical work by Narimanov and Kildishev (2009 Appl. Phys. Lett. 95 041106) an optical omnidirectional light absorber based on metamaterials was proposed, in which theoretical analysis and numerical simulations showed that all optical waves hitting the absorber are trapped and absorbed. Here we report the first experimental demonstration of an omnidirectional electromagnetic absorber in the microwave frequency. The proposed device is composed of non-resonant and resonant metamaterial structures, which can trap and absorb electromagnetic waves coming from all directions spirally inwards without any reflections due to the local control of electromagnetic fields. It is shown that the absorption rate can reach 99 per cent in the microwave frequency. The all-directional full absorption property makes the device behave like an 'electromagnetic black body', and the wave trapping and absorbing properties simulate, to some extent, an 'electromagnetic black hole.' We expect that such a device could be used as a thermal emitting source and to harvest electromagnetic waves.

Cheng, Qiang; Cui, Tie Jun; Jiang, Wei Xiang; Cai, Ben Geng

2010-06-01

473

Electromagnetic Attenuation by Solid Particle Aerosols.  

NASA Astrophysics Data System (ADS)

Theories of electromagnetic attenuation by absorption and scattering from aerosols of solid particles were evaluated and experimentally verified. Particles having specific physical and morphological properties were tested to maximize the mass extinction coefficients of the aerosols in several bands of the electromagnetic spectrum. Particulate materials were chosen based on theoretical predictions and compatible aerosolization schemes were developed for each material. Direct measurements of attenuation by the resulting aerosols were conducted in instrumented cloud chambers and a new measurement system using "stationary aerosols" was developed. The method of producing the stationary aerosols was optimized experimentally and results of the two measurement techniques were compared, validating the stationary aerosol approach as a viable alternative to chamber testing. Theoretical results were used to determine ideal particles for maximizing attenuation and particles with the appropriate parameters were designed and produced in the laboratory. A combination of aerosol and stationary aerosol testing was used to measure attenuations and extinction coefficients were computed as the figures of merit in evaluating the efficacy of each material. Materials with less than ideal parameters were tested to further validate the theoretical predictions. Materials produced as testing particulates included deflagrated graphitic oxides, charge transfer salts, iron whiskers, and aluminum flake with varying levels of passivation. Product characterizations were done using electron microscopies and image analysis, x-ray spectroscopies and electron spectroscopies. The same methods were used to verify manufacturers' specifications for commercially available materials tested. Characterization results were used to calculate theoretical predictions. Dissemination schemes investigated included sonic velocity pneumatic nozzles, mechanical systems, magnetic systems and material specific reaction systems. Figures of merit for dissemination systems were determined in terms of aerosolized yields, fall rates, and extents of agglomeration.

Petersen, Erica Ray

1991-02-01

474

Studies on a passive electromagnetic damper  

Microsoft Academic Search

The passive electromagnetic damper has the same configuration as that of the electromagnetic bearing, but no sensors and no\\u000a closed loop control are needed. Its robustness and no-contact structure are its great advantages. When the rotor vibrates,\\u000a the electromagnetic field intensity in the air gap is altered, then fluctuating currents in the damper coils and eddy currents\\u000a inside the surface

Shui-ying Zheng; Xiao-hong Pan; Zhen-fei Ma

2006-01-01

475

Pulsed Electromagnet Emat for High Temperatures  

NASA Astrophysics Data System (ADS)

We presented recently a design of Electromagnetic Acoustic Transducer (EMAT) that uses a pulsed electromagnet to provide the required magnetic field for operation. This new EMAT exhibited a significant improvement in the generated ultrasonic signal amplitude and signal to noise ratio, for operation on mild steel samples at room temperature, compared to equivalent EMATs that use permanent magnets. Results for using the pulsed electromagnet EMAT to generate and detect shear waves in mild steel at elevated temperatures are presented here.

Hernandez-Valle, F.; Dixon, S.

2010-02-01

476

Electromagnetic interactions at RHIC and LHC  

E-print Network

At LHC energies the Lorentz factor will be 3400 for the Pb + Pb collisions and the electromagnetic interactions will play important roles. Cross sections for the electromagnetic particle productions are very large and can not be ignored for the lifetimes of the beams and background. In this article, we are going to study some of the electromagnetic processes at RHIC and LHC and show the cross section calculations of the electron-positron pair production with the giant dipole resonance of the ions.

M. C. Guclu

2008-11-15

477

Electromagnetic wave scattering by Schwarzschild black holes  

E-print Network

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.

Luís C. B. Crispino; Sam R. Dolan; Ednilton S. Oliveira

2009-05-20

478

Electromagnetic Imaging Methods for Nondestructive Evaluation Applications  

PubMed Central

Electromagnetic nondestructive tests are important and widely used within the field of nondestructive evaluation (NDE). The recent advances in sensing technology, hardware and software development dedicated to imaging and image processing, and material sciences have greatly expanded the application fields, sophisticated the systems design and made the potential of electromagnetic NDE imaging seemingly unlimited. This review provides a comprehensive summary of research works on electromagnetic imaging methods for NDE applications, followed by the summary and discussions on future directions. PMID:22247693

Deng, Yiming; Liu, Xin

2011-01-01

479

Manager's Role in Electromagnetic Interference (EMI) Control  

NASA Technical Reports Server (NTRS)

This presentation captures the essence of electromagnetic compatibility (EMC) engineering from a project manager's perspective. It explains the basics of EMC and the benefits to the project of early incorporation of EMC best practices. The EMC requirement products during a project life cycle are identified, along with the requirement verification methods that should be utilized. The goal of the presentation is to raise awareness and simplify the mystique surrounding electromagnetic compatibility for managers that have little or no electromagnetics background

Sargent, Noel B.; Lewis, Catherine C.

2013-01-01

480

Some Student Conceptions of Electromagnetic Induction  

Microsoft Academic Search

Introductory electromagnetism is a central part of undergraduate physics. Although there has been some research into student\\u000a conceptions of electromagnetism, studies have been sparse and separated. This study sought to explore second year physics\\u000a students’ conceptions of electromagnetism, to investigate to what extent the results from the present study are similar to\\u000a these results from other studies, and to uncover

Wai Meng Thong; Richard Gunstone

2008-01-01

481

Thin sheet casting with electromagnetic pressurization  

SciTech Connect

An apparatus, method and system for the casting of thin strips or strips of metal upon a moving chill block that includes an electromagnet located so that molten metal poured from a reservoir onto the chill block passes into the magnetic field produced by the electromagnet. The electromagnet produces a force on the molten metal on said chill block in the direction toward said chill block in order to enhance thermal contact between the molten metal and the chill block.

Walk, Steven R. (Winterport, ME); Slepian, R. Michael (Pittsburgh, PA); Nathenson, Richard D. (Pittsburgh, PA); Williams, Robert S. (Fairfield, OH)

1991-01-01

482

Photoionization electron spectra in a system interacting with a neighboring atom  

SciTech Connect

Photoelectron ionization spectra of a system interacting with a neighbor two-level atom are investigated using the Laplace-transform method. These spectra are typically composed of several peaks. Photoelectron ionization spectra conditioned by the measurement on the two-level atom show oscillations at the Rabi frequency. The presence of spectral zeros occurring periodically with the Rabi period is predicted. This phenomenon is analyzed in detail.

Perina, Jan Jr. [Institute of Physics of AS CR, Joint Laboratory of Optics, 17. listopadu 50a, 772 07 Olomouc (Czech Republic); Luks, Antonin; Perinova, Vlasta [Palacky University, RCPTM, Joint Laboratory of Optics, 17. listopadu 12, 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

483

Electromagnetic Scattering from Foliage Camouflaged Hard Targets,  

E-print Network

Electromagnetic Scattering from Foliage Camouflaged Hard Targets, in VHF-band Mojtaba Dehmollaian. Then using this formulation, and single scattering theory the backscattered field from a camouflaged complex

Sarabandi, Kamal

484

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

485

Noncontacting ultrasonic and electromagnetic HTS tape NDE  

SciTech Connect

Two noncontacting nondestructive evaluation techniques (electromagnetic and ultrasonic) for inspection of high temperature superconducting tapes are described. Results for Ag-clad BSCCO tapes are given.

Telschow, K.L.; Bruneel, F.W.; Walter, J.B.; Koo, L.S.

1996-10-01

486

Phase-space representation of electromagnetic radiometry  

NASA Astrophysics Data System (ADS)

The phase-space representation of electromagnetic radiometry is founded on the electromagnetic generalized radiance tensors, which allow overcoming the limitations due to the scalar electromagnetic generalized radiances. The fundamental quantities of both scalar generalized radiometry and classical radiometry or photometry become particular cases. The transport of measurable radiometric quantities by the electromagnetic field is described in terms of the propagation of the contributions from individual radiators and their redistribution over each wavefront on propagation. A physical meaning is given to the negative values of the generalized radiance, which gives new insights into Poynting's theory of energy transport.

Castaneda, Roman

2009-03-01

487

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