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1

Red shift in spectra of galaxies as a consequence of gravitational radiation of the same level as electromagnetic  

E-print Network

In elaboration of the results presented earlier the red shift is also regarded in this investigation as a widening of electromagnetic radiation spectra, determined by the existence of gravitational radiation of a banded spectrum of the same level as electromagnetic.

S. I. Fisenko; I. S. Fisenko

2010-01-07

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

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

4

Asymmetrical spectra due to atomic coherence of neighboring excited levels  

NASA Astrophysics Data System (ADS)

In this paper, we propose to use two five-level systems to analyze asymmetrical transmitted spectra of probe field in traditional three-level ?-type and ladder-type systems for electromagnetically induced transparency (EIT) and photonic band-gap in atoms with a strong coupling field. The five-level systems are constructed by choosing two additional levels adjoining to one of the upper or middle levels in a three-level ?-type and ladder-type systems. Due to inhibited transition of the coupling laser to one of the two chosen levels, the asymmetrical absorptions at dressed states are obtained to be consistent with experimental observation in the original three-level systems.

Chen, Zhuo Ren; Su, Xue Mei

2013-07-01

5

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

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

6

Spectra  

NSDL National Science Digital Library

Spectra is a very informative website about how astronomers use spectra to understand what stars are made of, their structures, and their evolution. The page begins with an introduction to the electromagnetic spectrum and then goes into great detail about the properties of light. Then it talks about how matter both creates and destroys radiation. Then it discusses how to interpret absorption and emission lines. The website ends with how astronomers use spectra to understand stars, galaxies, other objects in the universe.

Kaler, James

2004-07-16

7

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

PubMed

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

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

2013-01-01

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

Interpretation of the properties of the spectra of electromagnetic radiation emitted from high-voltage equipment  

NASA Astrophysics Data System (ADS)

The analysis of spectra of intrinsic electromagnetic radiation (EMR) emitted from high-voltage equipment makes it possible to obtain information from which the intensity of discharge processes that occur in the insulation can be determined. The purpose is to identify indicators that characterize the internal technical condition of a component of the equipment. Radiation emitted from external sources should be filtered out from the overall picture of recorded EMR. The spectra of EMR emitted from various units of the equipment are individual ones, but for similar units of the equipment they have similar structure and similar general properties. Examples of actual spectra of EMR are given. The most probable interferences are analyzed. The principles of signal selection are discussed. The special features of interpreting the dependence of amplitudes of natural frequencies of a spectrum on the time are examined. The possibilities for determining natural frequencies of a component of the equipment are shown.

Kinsht, N. V.; Petrun'ko, N. N.

2012-12-01

10

Physical interpretation for the correlation spectra of electromagnetically-induced-transparency resonances.  

PubMed

The phenomenon called Electromagnetically Induced Transparency (EIT) may induce different types of correlation between two optical fields interacting with an ensemble of atoms. It is presently well known, for example, that in the vicinity of an EIT resonance the dominant correlations at low powers turn into anti-correlations as power increases. Such correlation spectra present striking power-broadening-independent features, with the best condition for measuring the characteristic linewidth occurring at the highest powers. In the present work we investigate the physical mechanisms responsible for this set of observations. Our approach is first to reproduce these effects in a better controlled experimental setup: a cold atomic ensemble, obtained from a magneto-optical trap. The results from this conceptually simpler system were then compared to a correspondingly simpler theory, which clearly relates the observed features to the interplay between two key aspects of EIT: the transparency itself and the steep normal dispersion near two-photon resonance. PMID:23389133

Felinto, D; Cruz, L S; de Oliveira, R A; Florez, H M; de Miranda, M H G; Nussenzveig, P; Martinelli, M; Tabosa, J W R

2013-01-28

11

Patterns of energy levels and spectra for polyatomic molecules  

SciTech Connect

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

Harter, W.G.

1983-01-01

12

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

13

Electromagnetically induced absorption in ?-three-level system driven by bichromatic coupling field  

NASA Astrophysics Data System (ADS)

The probe absorption spectrum of the ?-three-level system driven by bichromatic coupling field and weak probe field is investigated. We obtain the probe absorption spectra for different frequency detunings of coupling field by solving the density matrix equation and numerical analysis. Three electromagnetically induced absorption (EIA) peaks are simultaneously observed in the absorption profile of probe field. We report the dependence of position and relative intensity of EIA on the frequency detuning of the bichromatic coupling field. The results show that central EIA always appears at the resonant frequency of probe field, with the constant intensity. The position of the secondary EIA vary with the frequency detuning of coupled field, and the intensity of the absorption peaks decrease with the increasing detuning.

Yang, Li-jun; Yan, Zhan-fei; Wang, Yu-ning; Guo, Shu-qing

2012-11-01

14

Effects of electromagnetic pulse on serum element levels in rat.  

PubMed

Electromagnetic pulse (EMP) was a potentially harmful factor to the human body, and a biological dosimetry to evaluate effects of EMP is necessary. Little is known about effects of EMP on concentration of macro and trace elements in serum so far. In this study, Sprague-Dawley rats were randomly divided into 50-kV/m EMP-exposed group (n = 10), 100-kV/m EMP-exposed group (n = 10), 200-kV/m EMP-exposed group (n = 40), and the sham-exposed group (n = 20). The macro and trace element concentrations in serum were examined at 6, 12, 24, and 48 h after EMP exposure at different electric field intensities. Compared with the sham-exposed groups, the concentration of sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), zinc (Zn), copper (Cu), iron (Fe), selenium (Se), and manganese (Mn) in rat serum was not changed significantly within 48 h after 200 pulses of EMP exposure at electric field intensity of 50, 100, and 200 kV/m although the K level was decreased and the Ca level was increased with the electric field intensity of EMP increasing. In addition, there was a tendency that the Zn level was decreased with the time going on within 48 h after EMP exposure. Under our experimental conditions, EMP exposure cannot affect the concentration of macro and trace elements in rat serum. There was no time-effect or dose-effect relationship between EMP exposure and serum element levels. The macro and trace elements in serum are not suitable endpoints of biological dosimetry of EMP. PMID:24497087

Li, Kangchu; Ma, Shirong; Ren, Dongqing; Li, Yurong; Ding, Guirong; Liu, Junye; Guo, Yao; Guo, Guozhen

2014-04-01

15

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.

16

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

17

Determination of the metal nanometer layer thickness and semiconductor conductivity in metal-semiconductor structures from electromagnetic reflection and transmission spectra  

Microsoft Academic Search

Interaction of electromagnetic radiation with metal-semiconductor nanometer structures is studied theoretically and experimentally.\\u000a A technique for nondestructive multiparametric control of the electrophysical parameters of metal nanometer layers and semiconductor\\u000a conductivity in metal-semiconductor structures using electromagnetic reflection and transmission spectra is proposed and tested\\u000a experimentally.

D. A. Usanov; A. V. Skripal; A. V. Abramov; A. S. Bogolyubov

2006-01-01

18

Linewidth and lifetime of atomic levels and the time evolution of spectra and coincidence spectra  

SciTech Connect

The time-dependent theory of an atomic cascade decay process is discussed. We show that it is useful to measure the spectra of the emitted particles (electrons or photons) as a function of time and introduce time-dependent spectra and time-dependent coincidence spectra. The analysis reveals that there are several timescales involved in the atomic cascades and in the respective spectra. The work prepares the ground for the discussion of molecules, clusters, and solids, where the nuclear dynamics strongly participate in the cascade decay process making it much more complex.

Chiang, Y.-C.; Kuleff, Alexander I.; Cederbaum, Lorenz S. [Theoretische Chemie, Universitaet Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg (Germany); Demekhin, Philipp V. [Institute fuer Physik, Experimental-Physik IV, Universitaet Kassel, Heinrich-Plett-Str. 40, D-34132 Kassel (Germany); Scheit, Simona [Department of Basic Science, Graduate School of Arts and Sciences, University of Tokyo, Komaba, 153-8902 Tokyo (Japan)

2010-03-15

19

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

20

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

21

Level Density Parameter: A Tool to Study the Particle Spectra  

SciTech Connect

The compound nucleus {sup 76}Kr* is formed in the heavy-ion fusion reactions by an asymmetric entrance channel {sup 12}C+{sup 64}Zn and the symmetric entrance channel {sup 31}P+{sup 45}Sc at the excitation energy of 75 MeV and angular momentum of 39 eta. Neutron energy spectra of the asymmetric system ({sup 12}C+{sup 64}Zn) at different angles are well described by the statistical model predictions using the normal value of the level density parameter a = A/8 MeV{sup -1}. However, in the case of the symmetric system ({sup 31}P+{sup 45}Sc), the statistical model interpretation of the data requires the change in the value of a = A/10 MeV{sup -1}. The delayed evolution of the compound system in case of the symmetric {sup 31}P+{sup 45}Sc system may lead to the formation of a temperature equilibrated dinuclear complex, which may be responsible for the neutron emission at higher temperature, while the protons and alpha particles are evap orated after neutron emission when the system is sufficiently cooled down and the higher lambda-values do not contribute in the formation of the compound nucleus for the symmetric entrance channel in case of charged particle emission.

Kumar, Ajay [Department of Physics, Banaras Hindu University, Varanasi-221005 (India); Kumar, A.; Singh, G.; Singh, Hardev; Govil, I. M. [Department of Physics, Panjab University, Chandigarh-160014 (India); Singh, R. P.; Kumar, Rakesh; Golda, K. S. [Inter University Accelerator Centre, New Delhi-110067 (India)

2010-04-30

22

Relationships Between Complex Core Level Spectra and Materials Properties  

SciTech Connect

The XPS of many oxides are quite complex and there may be several peaks of significant intensity for each subshell. These peaks arise from many-electron effects, which normally are treated with configuration interaction (CI) wavefunctions where static correlation effects are taken into account. It is common to use semiempirical methods to determine the matrix elements of the CI Hamiltonian and there are few rigorous CI calculations where parameters are not adjusted to fit experiment. In contrast, we present, in the present work, theoretical XPS spectra obtained with rigorous CI wavefunctions for CeO2 where the XPS are especially complex; several different core levels are studied. This study uses an embedded CeO8 cluster model to represent bulk CeO2 and the relativistic CI wavefunctions are determined using four-component spinors from Dirac-Fock calculations. In particular, we examine the importance of interatomic many-body effects where there is a transfer of electrons from occupied oxygen 2p orbitals into empty cation orbitals as it is common to ascribe the complex XPS to this effect. We also contrast the importance of many-body charge-transfer effects for the isoelectronic cations of Ce4+ and La3+. The long-range goal of this work is to relate the XPS features to the nature of the chemical bonding in CeO2 and we describe our progress toward this goal.

Nelin, Constance J.; Bagus, Paul S.; Ilton, Eugene S.; Chambers, Scott A.; Kuhlenbeck, Helmut; Freund, Hans-Joachim

2010-12-01

23

Investigation of Ion Gyroharmonic Structuring in the Simulated Electromagnetic Emission Spectra  

NASA Astrophysics Data System (ADS)

One of the most prominent features in the SEE spectrum is the so-called down-shifted maximum or DM which is believed to be produced from a three-way parametric decay instability from the pump electromagnetic wave into an upper hybrid wave UH and a lower hybrid LH wave. Its interesting behavior near electron gyroharmonics has been well studied and documented now for two decades and it has become important for ionospheric diagnostic purposes. Recent unsatisfactorily explained observations at HAARP have shown a new decay mechanism in which possible decay of the electromagnetic pump wave into ion Bernstein-type modes (rather than lower hybrid modes) are present. Such new SEE features obviously may have important diagnostic consequences for ion composition and ion behavior in the heated volume as well as information on the ambient magnetic field. The objective of this experiment is to shed light on new SEE feature. It should be noted that this is a physically different process than the recently observed magnetized stimulated Brillouin scatter. These structures are believed to result from a three-way parametric decay process from the pump electromagnetic wave into an electron Bernstein wave and oxygen Bernstein waves in much the same manner as the DM is generated although this proposition has not been validated. The objective of this experiment was to explore this proposition in further detail by sweeping the pump frequency through the second electron cyclotron harmonic frequency and observe the behavior of the creation and suppression of this new so-called oxygen Bernstein decay instability. Below is the spectrum of received signal with pump frequency shifted to 0 Hz. The three peaks on the left of pump frequency with the arrows on it are approximately 50 Hz apart. This preliminary result of the experiment agrees about the existence of the ion Bernstein modes below the pump frequency near the second gyroharmonic as will be observed in the presentation. SEE Spectrum of received signal

Bordikar, M. R.; Bernhardt, P. A.; Scales, W. A.; Briczinski, S. J.; San Antonio, G.; Selcher, C. A.

2010-12-01

24

Rotationally resolved photoelectron spectra from vibrational autoionization of NO Rydberg levels  

E-print Network

Rotationally resolved photoelectron spectra from vibrational autoionization of NO Rydberg levels Received 3 September 1996; accepted 25 October 1996 Rotationally resolved photoelectron spectra from-of-flight photoelectron spectroscopy. The photoelectron spectra show that both even-l and odd-l continuum partial waves

Zare, Richard N.

25

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

NASA Astrophysics Data System (ADS)

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?u+1(v=13,J=14) to the upper state G?g1(v=11,J=14) of Li27 , the fluorescence from both A?u+1 and G?g1 states was drastically reduced as the weak probe laser was tuned through the resonance transition between the ground state X?g+1(v=4,J=15) and the excited state A?u+1(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?g1(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; Lyyra, A. Marjatta

2006-04-01

26

Electromagnetically induced transparency in systems with degenerate autoionizing levels in ?-configuration  

E-print Network

We discuss a \\Lambda-like model of atomic levels involving two autoionizing (AI) states of the same energy. The system is irradiated by two external electromagnetic fields (strong -- driving and weak -- probing ones). For such a system containing degenerate AI levels we derive the analytical formula describing the medium susceptibility. We show that the presence of the second AI level lead to the additional electromagnetically induced transparency (EIT) window appearance. We show that the characteristic of this window can be manipulated by changes of the parameters describing the interactions of AI levels with other ones. This is a new mechanism which leads to additional transparency windows in EIT model, that differs from the mechanism, where a bigger number of Zeeman sublevels is taken into account.

T. Bui Dinh; W. Leo?ski; V. Cao Long; J. Pe?ina Jr

2013-02-21

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

Estimating the Level of Motion Sickness Based on EEG Spectra  

Microsoft Academic Search

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

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

29

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

30

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,...

31

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

32

[Selective excitation spectra and energy level structure of Dy3+:ThO2 crystal].  

PubMed

Dy3+:ThO2 crystal was grown by the flux technique for the first time. The emission spectra, excitation spectra and fluorescence decay curves were measured and discussed. By using emission spectra obtained under selective dye laser excitation at 12 K, together with the crystal-field theory, the site symmetry of Dy3+ ions in ThO2 was determined as C3 nu and its energy level structure was tabulated. The lifetime of radiative level 4F9/2 was also determined as 0.40 ms. PMID:12945248

Yin, M; Krupa, J C

2001-08-01

33

Influence of multi-level impurities on the dynamics of ultrashort electromagnetic pulses in carbon nanotubes  

NASA Astrophysics Data System (ADS)

Based on Maxwell's equations, we study the propagation of an ultrashort electromagnetic pulse through an array of carbon nanotubes with multi-level impurities. The effective equation for the vector potential of the electromagnetic field is first derived analytically and then solved numerically. We subsequently analyze the dependence of the pulse shape on the parameters of the energy spectrum of impurities, and more precisely on the impurity levels. Our analysis predicts a significant decrease in the pulse amplitude during the transient, which is associated with the competitive effects of dispersion and other nonlinear effects. We also uncover the effects of the hopping integrals and band gap of deep impurities on the pulse tail decay.

Zhukov, Alexander V.; Bouffanais, Roland; Konobeeva, Natalia N.; Belonenko, Mikhail B.; George, Thomas F.

2014-05-01

34

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

Microsoft Academic Search

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

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

2009-01-01

35

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

36

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

SciTech Connect

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

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

2011-05-15

37

New Fe I level energies and line identifications from stellar spectra  

E-print Network

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 analysis of ultraviolet laboratory iron absorption spectra, optical laboratory iron emission spectra, and the solar infrared spectrum. In this work we use as sources the 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 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 37 Fe I levels. Many new level energies are higher than those...

Peterson, Ruth C

2014-01-01

38

Electromagnetically induced self-imaging in four-level atomic system.  

PubMed

In this paper, a special gradient-index electromagnetically induced transparency medium is induced with a Gaussian control field, which can be realized in a four-level ??Rb cold atomic cloud. Special directional self-imaging and imaging transforming properties are studied in this work. Simulated results show that a complex object can be imaged in the cold atoms, as the control field substituted with the elliptical Gaussian beam, then the self-imaging is directional, which has potental application in encryption. PMID:24663467

Wang, Feng; Wang, Chunfang; Cheng, Jing; Zhang, Dawei

2014-03-20

39

Electromagnetically Induced Grating via Coherently Driven Four-Level Atoms in a N-Type Configuration  

NASA Astrophysics Data System (ADS)

We propose a scheme to generate an electromagnetically induced grating via coherently driven four-level atoms in a N-type configuration in the presence of a standing signal field, a coupling field and a probe field. We show that a nearly ideal phase grating can be realized by adjusting the frequency detuning of signal field, the interaction length of atomic medium, and the ratio of the intensity between the signal field and the coupling field. The first-order diffraction efficiency of the grating is about 29.9 %, which is close to that of an ideal sinusoidal phase grating.

Guo, Yu; Li, Jia-Yu; Liu, Ming

2014-08-01

40

Emission spectra and intrinsic optical bistability in a two-level medium  

Microsoft Academic Search

Scattering of resonant radiation in a dense two-level medium is studied theoretically accounting for local field effects and renormalisation of the resonance frequency. Intrinsic optical bistability is viewed as switching between different spectral patterns of fluorescent light controlled by the incident field strength. Response spectra are calculated analytically for the entire hysteresis loop of atomic excitation. The equations to describe

M. G. Gladush; D. V. Kuznetsov; Vl. K. Roerich

2011-01-01

41

Improved Experimental and Theoretical Energy Levels of Carbon I from Solar Infrared Spectra  

NASA Technical Reports Server (NTRS)

We have improved the energy levels in neutral carbon using high resolution infrared solar spectra. The main source is the ATMOS spectrum measured by the Fourier transaform spectroscopy technique from 600 to 4800 cm-1, supplemented by the MARK IV balloon data, covering from 4700 to 5700 cm-1.

Chang, Edward S.; Geller, Murray

1997-01-01

42

Revisiting the Valence-Band and Core-Level Photoemission Spectra of NiO  

NASA Astrophysics Data System (ADS)

We have reexamined the valence-band (VB) and core-level electronic structure of NiO by means of hard and soft x-ray photoemission spectroscopies. The spectral weight of the lowest energy state was found to be enhanced in the bulk sensitive Ni 2p core-level spectrum. A configuration-interaction model including a bound state screening has shown agreement with the core-level spectrum and off- and on-resonance VB spectra. These results identify the lowest energy states in the core-level and VB spectra as the Zhang-Rice (ZR) doublet bound states, consistent with the spin-fermion model and recent ab initio calculations within dynamical mean-field theory. The results indicate that the ZR character first ionization (the lowest hole-addition) states are responsible for transport properties in NiO and doped NiO.

Taguchi, M.; Matsunami, M.; Ishida, Y.; Eguchi, R.; Chainani, A.; Takata, Y.; Yabashi, M.; Tamasaku, K.; Nishino, Y.; Ishikawa, T.; Senba, Y.; Ohashi, H.; Shin, S.

2008-05-01

43

Mirror symmetry in the energy spectra of $n$-level systems  

E-print Network

The energy spectrum of a system of $N_a$ atoms of $n$ levels interacting with a one-mode electromagnetic field is studied in the dipole and rotating wave approximations. We find that, under the resonant condition, it exhibits a mirror symmetry with respect to the energy $E=M$ where $M$ the total number of excitations. Thus, for any eigenstate $|\\psi_M^{+}\\rangle$ with energy $E=M+{\\cal E}$ there exists a related eigenstate $|\\psi_M^{-}\\rangle$ with energy $E=M-{\\cal E}$ via the unitary parity operator in the number of photons . This is independent of the dipolar coupling between the levels. We give explicit examples for $3$-level systems.

S. Cordero; O. Castaños; R. López--Peña; E. Nahmad--Achar

2014-03-15

44

Identification of electromagnetic parameters of a wall and determination of radar signal level behind a wall  

NASA Astrophysics Data System (ADS)

One of the challenges of using synthetic aperture radar (SAR) to detect a man behind a wall is determining the amount of signal attenuation introduced by the signal's propagation through the wall. This attenuation is difficult to determine because the thickness and the electromagnetic properties of the wall are normally not known a priori. We describe a procedure for estimating the relative permittivity, conductivity, and thickness of the wall that minimize the error between physics-based predicted values of wall return and the corresponding values of the SAR image. The accuracy of the prediction is a function of the resolution of the SAR image relative to the thickness of the wall-the SAR image must have sufficient resolution such that the locations of the front and rear surfaces of a uniform wall can be estimated from the SAR image. The signal level behind the wall, or equivalently the signal attenuation by the wall is then determined from the estimates of the thickness and electromagnetic parameters. We demonstrate the effectiveness of this identification procedure using data generated by XPATCH simulations of three different wall materials.

Khatri, Hiralal; Le, Calvin

2006-05-01

45

Peak shape analysis of core level photoelectron spectra using UNIFIT for WINDOWS  

Microsoft Academic Search

Several approaches used in the peak shape analysis of core level spectra for the purpose of modelling of both peak shapes\\u000a and background profiles will be discussed. A universal program is presented, which combines options for adequate modelling\\u000a of the peak shapes and background, implementation of a successful numerical algorithm for an iterative non-linear parameter\\u000a estimation procedure, and a flexible

R. Hesse; T. Chassé; R. Szargan

1999-01-01

46

Emission spectra and intrinsic optical bistability in a two-level medium  

Microsoft Academic Search

Scattering of resonant radiation in a dense two-level medium is studied\\u000atheoretically with account for local field effects and renormalization of the\\u000aresonance frequency. Intrinsic optical bistability is viewed as switching\\u000abetween different spectral patterns of fluorescent light controlled by the\\u000aincident field strength. Response spectra are calculated analytically for the\\u000aentire hysteresis loop of atomic excitation. The equations to

M. G. Gladush; D. V. Kuznetsov; A. A. Panteleev; Vl. K. Roerich

2010-01-01

47

Electromagnetically induced transparency in an inverted Y-type four-level system  

NASA Astrophysics Data System (ADS)

The interaction of a weak probe laser with an inverted Y-type four-level atomic system driven by two additional coherent fields is investigated theoretically. Under the influence of the coherent coupling fields, the steady-state linear susceptibility of the probe laser shows that the system can have single or double electromagnetically induced transparency windows depending on the amplitude and the detuning of the coupling lasers. The corresponding index of refraction associated with the group velocity of the probe laser can be controlled at both transparency windows by the coupling fields. The propagation of the probe field can be switched from superluminal near the resonance to subluminal on resonance within the single transparency window when two coupling lasers are on resonance. We propose an atomic 87Rb system for experimental observation.

Qi, Jianbing

2010-01-01

48

Phase control of electromagnetically induced transparency in a four-level system  

NASA Astrophysics Data System (ADS)

We present a theoretical study on the frequency position and the linetype of Electromagnetically Induced Transparency (EIT) in a four-level atomic system with a coupling field, two microwave fields and a probe field. The absorption spectrum which is characterized by two EIT windows is obtained by a weak probe field scanning corresponding transition. It can be found that the frequency position and the linetype of EIT change with the relative phase of the two microwave fields. The frequnecy interval reaches the minimum when the relative phase is reverse. If two microwave fields have the same strength and reverse phase, the absorption spectrum will exhibit an EIT. This proposes a way to controlling frequency position of EIT by modulating the relative phase between two fields.

Yang, Lijun; Zhao, Min; Lv, Dongqi

2010-11-01

49

Emission spectra and intrinsic optical bistability in a two-level medium  

NASA Astrophysics Data System (ADS)

Scattering of resonant radiation in a dense two-level medium is studied theoretically accounting for local field effects and renormalisation of the resonance frequency. Intrinsic optical bistability is viewed as switching between different spectral patterns of fluorescent light controlled by the incident field strength. Response spectra are calculated analytically for the entire hysteresis loop of atomic excitation. The equations to describe the non-linear interaction of an atomic ensemble with light are derived from the Bogolubov-Born-Green-Kirkwood-Yvon hierarchy for reduced single particle density matrices of atoms and quantised field modes and their correlation operators. The spectral power of scattered light with separated coherent and incoherent constituents is obtained straightforwardly within the hierarchy. The formula obtained for emission spectra can be used to distinguish between possible mechanisms suggested to produce intrinsic bistability in experiments.

Gladush, M. G.; Kuznetsov, D. V.; Roerich, Vl. K.

2011-10-01

50

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

51

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

PubMed

The cyclopropene radical cation (c-C3H??) 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 X? (2)B2 ground electronic state of c-C3H?? 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 C(2v)-symmetric R0 structure for the ground electronic state of c-C3H??. Two vibrational modes of c-C3H?? 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??) to the CH2 torsional mode (???, A2 symmetry) and of the second-lowest-frequency mode (?210 cm(-1) in c-C3H??) to a mode combining a CH out-of-plane with a CH2 rocking motion (????, B2 symmetry). The potential energy along the CH2 torsional coordinate is flat near the equilibrium structure and leads to a pronounced anharmonicity. PMID:25134581

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

2014-08-14

52

Research Investigation Directed Toward Extending the Useful Range of the Electromagnetic Spectrum. [atomic spectra and electronic structure of alkali metals  

NASA Technical Reports Server (NTRS)

The report discusses completed and proposed research in atomic and molecular physics conducted at the Columbia Radiation Laboratory from July 1972 to June 1973. Central topics described include the atomic spectra and electronic structure of alkali metals and helium, molecular microwave spectroscopy, the resonance physics of photon echoes in some solid state systems (including Raman echoes, superradiance, and two photon absorption), and liquid helium superfluidity.

Hartmann, S. R.; Happer, W.

1974-01-01

53

Sensitivity of electromagnetic spectra to equation of state and initial energy density in the Pb+Pb collisions at SPS  

E-print Network

We study Pb+Pb collisions at 158 A GeV/c using a hydrodynamical approach. We test different equations of state (EoSs) and different initial conditions and show that there are more than one initial state for each EoS which reproduce the observed hadronic spectra. We also find that different equations of state favour different freeze-out temperature. Simultaneously we calculate the thermal dilepton and photon spectra for each EoS and initial state. We compare the dilepton mass spectrum to data measured by the CERES collaboration and find that the differences in spectra obtained using different EoSs and initial states are not resolvable within the current experimental resolution. However, at invariant masses over 2 GeV the difference in the yield due to various initial states is close to an order of magnitude. We also study the rapidity distribution of lepton pairs and find that for masses around 800 MeV the shape of the distribution depends strongly on the EoS.

Pasi Huovinen; P. V. Ruuskanen; Josef Sollfrank

1998-07-29

54

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

55

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

2011-04-15

56

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

57

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

NASA Astrophysics Data System (ADS)

Context. 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. Aims: 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. Methods: 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 of parameters for the best-fit that leads to intensities characteristic of each group. We used both isothermal and multitemperature assumptions, the latter described by differential emission measure (DEM) distributions. RESIK spectra cover the wavelength range (3.3-6.1 Å). This includes emission lines of highly ionized Si, S, Cl, Ar, and K, which are suitable for evaluating temperature and emission measure, were used. Results: The RESIK spectra during these intervals of very low solar activity for the first time provide information on the temperature structure of the quiet corona. Although most of the emission seems to arise from plasma with a temperature between 2 MK and 3 MK, there is also evidence of a hotter plasma (T ~ 10 MK) with an emission measure 3 orders smaller than the cooler component. Neither coronal nor photospheric element abundances appear to describe the observed spectra satisfactorily.

Sylwester, B.; Sylwester, J.; Phillips, K. J. H.

2010-05-01

58

Propagation of two short laser pulse trains in a ?-type three-level medium under conditions of electromagnetically induced transparency  

NASA Astrophysics Data System (ADS)

We investigate the dynamics of a pair of short laser pulse trains propagating in a medium consisting of three-level ?-type atoms by numerically solving the Maxwell-Schrödinger equations for atoms and fields. By performing propagation calculations with different parameters, under conditions of electromagnetically induced transparency, we compare the propagation dynamics by a single pair of probe and coupling laser pulses and by probe and coupling laser pulse trains. We discuss the influence of the coupling pulse area, number of pulses, and detunings on the probe laser propagation and realization of electromagnetically induced transparency conditions, as well on the formation of a dark state.

Buica, Gabriela; Nakajima, Takashi

2014-12-01

59

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

60

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

61

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

NASA Technical Reports Server (NTRS)

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, SAMPBX, and STEREO spacecraft and extend from approximately 0.1 to approximately 500-700 MeV. All of the proton spectra exhibit spectral breaks at energies ranging from approximately 2 to approximately 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 greater than 40 MeV/nuc. In the energy range 45 to 80 MeV/nucleon about approximately 50% of GLE events have properties in common with impulsive He-3-rich SEP events, including enrichments in Ne/O, Fe/O, Ne-22/Ne-20, and elevated mean charge states of Fe. These He-3 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(sub Fe) is approximately equal to +20 if the acceleration starts at approximately 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.; COhen, C. M. S.; Labrador, A. W.; Leske, R. A.; Looper, M. D.; Haggerty, D. K.; Mason, G. M.; Mazur, J. E.; vonRosenvinge, T. T.

2012-01-01

62

Examination of level density prescriptions in the interpretation of high energy gamma-ray spectra  

E-print Network

High energy $\\gamma$-ray spectra measured by our group involving the compound nuclei (CN) $^{63}$Cu at excitation energy ($E^*$) $\\sim$ 36 MeV with average angular momentum ($J$) = 12 - 17 $\\hbar$, $^{97}$Tc at $E^* \\sim$ 29 - 50 MeV with $J$ = 12 - 14 $\\hbar$, $^{113}$Sb at $E^*$ = 109 MeV and 121 MeV with $J$ = 49 - 59 $\\hbar$ and $^{201}$Tl at $E^*$ = 39.5, 47.5 MeV with $J$ = 18 - 24 $\\hbar$ 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 correct statistical model description of high energy $\\gamma$-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 $\\gamma$-r...

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

2014-01-01

63

Spectra From Space : Main Menu  

NSDL National Science Digital Library

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

1997-01-01

64

Modeling of the electromagnetic field and level populations in a waveguide amplifier: a multi-scale time problem  

E-print Network

A new algorithm based on auxiliary differential equation and finite difference time domain method (ADE-FDTD method) is presented to model a waveguide whose active layer is constituted of a silica matrix doped with rare-earth and silicon nanograins. The typical lifetime of rare-earth can be as large as some ms, whereas the electromagnetic field in a visible range and near-infrared is characterized by a period of the order of fs. Due to the large difference between these two characteristic times, the conventional ADE-FDTD method is not suited to treat such systems. A new algorithm is presented so that the steady state of rare earth and silicon nanograins electronic levels populations along with the electromagnetic field can be fully described. This algorithm is stable and applicable to a wide range of optical gain materials in which large differences of characteristic lifetimes are present.

Fafin, Alexandre; Dufour, Christian; Gourbilleau, Fabrice

2014-01-01

65

Two-dimensional electromagnetically induced cross-grating in a four-level tripod-type atomic system  

NASA Astrophysics Data System (ADS)

By using two orthogonal coupling standing-wave fields, we propose a scheme for a two-dimensional electromagnetically induced cross-grating (EICG) in a four-level tripod-type atomic system. Based on the electromagnetically induced transparency, the probe field will be diffracted and form the two-dimensional EICG through the interaction of the two coupling standing-wave fields. It is shown that the first-order diffraction intensity of the two-dimensional EICG depends observably on the detuning of the probe field and the Rabi frequencies of the two coupling standing-wave fields. The results may be used to develop novel photonic devices for use in quantum information processing, quantum networking and optical imaging.

Wang, Li; Zhou, Fengxue; Hu, Pidong; Niu, Yueping; Gong, Shangqing

2014-11-01

66

Electromagnetically induced transparency-assisted four-wave mixing process in the diamond-type four-level atomic system  

NASA Astrophysics Data System (ADS)

With electromagnetically induced transparency (EIT)-assisted configuration, we study the third-order nonlinear four-wave mixing (FWM) process in a diamond-type four-level atomic system both theoretically and experimentally. Following the proposal by the recent study (Willis et al., 2009), we introduce EIT contribution to the theoretical model which will enhance the conversion efficiency of the nonlinear process and narrow the linewidth of the FWM signal. By means of the coherent EIT effect, we get higher conversion efficiency at lower power level of incident beam in such atomic system. Compare to our previous models, the conversion efficiency in such diamond-type atomic system is much smaller which needs higher threshold temperature. In addition, the frequency dependences on incident beams reveal that the dipole transition of one-photon and two-photon processes affect this nonlinear process.

Wen, Feng; Zheng, Huaibin; Xue, Xinxin; Chen, Haixia; Song, Jianping; Zhang, Yanpeng

2014-11-01

67

A pilot neighborhood study towards establishing a benchmark for reducing electromagnetic field levels within single family residential dwellings.  

PubMed

Electromagnetic fields (EMF) permeate the built environment in different forms and come from a number of sources including electrical wiring and devices, wireless communication, 'energy-efficient' lighting, and appliances. It can be present in the indoor environment directly from indoor sources, or can be transmitted through building materials from outside sources. Scientists have identified it as an indoor environmental pollutant or toxin that has ubiquitously plagued developed nations causing a variety of adverse health effects such as sick-building syndrome symptoms, asthma, diabetes, multiple sclerosis, leukemia, electro-hypersensitivity (EHS), behavior disorders, and more. There is currently no international consensus on guidelines and exposure limits. This paper presents the results of 29 EMF field audits in single family residential dwellings located within an urban neighborhood in Toronto (Canada). The following EMF spectra were evaluated: radio frequency, power frequency electric fields, power frequency magnetic fields and high frequency voltage transients. The field audits were conducted in order to provide initial baseline statistics to be used in future studies and in order to be compared to a low-cost EMF reduction design incorporated within the Renovation2050 research house - located within the test neighborhood. The results show the low-cost reduction strategy to be effective, on average reducing exposure by 80% for high-intensity EMF metrics. Research of this nature has not been conducted with relation to the built environment and can be used to spark an industry movement to design for low-exposure to EMF in a residential context. PMID:23962434

Richman, Russell; Munroe, Alan James; Siddiqui, Yasmeen

2014-01-01

68

Nuclear Magnetic Resonance Inverse Spectra of InGaAs Quantum Dots: Atomistic Level Structural Information  

E-print Network

A wealth of atomistic information is buried within a self-assembled quantum dot (QD), carrying the legacy of 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. With this computational study, we identify what sorts of atomistic information can be tapped from a single InGaAs QD, as probed optically by the recently introduced highly sensitive inverse spectra nuclear magnetic resonance technique. To capture the fingerprints of alloying in the spectra, we compare In0.2Ga0.8As QD with the compound InAs QD of the same shape, as well as performing a search over the parameter space of the inverse spectra technique. We display how both the elemental nuclear properties and local bonding take roles. The arsenic nuclei with their small gyromagnetic ratio are the most vulnerable to strain at a given magnetic field. Furthermore, because of their large S44 gradient elastic tensor components, the deviation of the major electric ...

Bulutay, Ceyhun; Tartakovskii, A I

2014-01-01

69

Momentum spectra and charge ratios of muons at 30° and 75°. [Sea level, 50 to 1000 GeV  

Microsoft Academic Search

A measurement of the momentum spectra of cosmic-ray muons at sea level was completed using a large rotatable magnetic spectrometer. The muon flux at zenith angles of 30 and 75° and for energies from 50 GeV to beyond 1000 GeV is presented. The results are compared with calculations based on the conventional production of muons from the decay of ..pi..

H. Kasha; R. Kellog; B. Higgs; L. Leipuner; R. Larsen

1975-01-01

70

Coincident observation of lightning using spaceborne spectrophotometer and ground-level electromagnetic sensors  

NASA Astrophysics Data System (ADS)

The present study aims at assessing a new way to reveal properties of lightning flash, using the spectrophotometric data obtained by FORMOSAT-2/ISUAL which is the first spaceborne multicolor lightning detector. The ISUAL data was analyzed in conjunction with ground-based electromagnetic data obtained by Duke magnetic field sensors, NLDN, North Alabama Lightning Mapping Array (LMA), and University of Mississippi (UM) electric field change antennas operated around Kennedy Space Center. We first classified the observed events into cloud-to-ground (CG) and intra-cloud (IC) lightning based on the Duke and NLDN measurements and analyzed ISUAL data to clarify their optical characteristics. It was found that the ISUAL optical waveform of CG lightning was strongly correlated with the current moment waveform, suggesting that it is possible to evaluate the electrical properties of lightning from satellite optical measurement to some extent. The ISUAL data also indicated that the color of CG lightning turned to red at the time of return stroke while the color of IC pulses remained unchanged. Furthermore, in one CG event which was simultaneously detected by ISUAL and LMA, the observed optical emissions slowly turned red as the altitude of optical source gradually decreased. All of these results indicate that the color of lightning flash depends on the source altitude and suggest that spaceborne optical measurement could be a new tool to discriminate CG and IC lightning. In the presentation, we will also show results on the comparison between the ISUAL and UM electric field change data to clarify characteristics of each lightning process such as preliminary breakdown and return stroke.

Adachi, T.; Cohen, M.; Lu, G.; Cummer, S. A.; Blakeslee, R. J.; Marshall, T.; Stolzenburg, M.; Karunarathne, S.; Hsu, R.; Su, H.; Chen, A. B.; Takahashi, Y.; Mende, S. B.; Frey, H. U.

2012-12-01

71

The Effects of Electromagnetic Fields Generated from 1800 MHz Cell Phones on Erythrocyte Rheological Parameters and Zinc Level in Rats  

PubMed Central

Objective: The aim of this study was to investigate the effects of the electromagnetic field generated from the 1800 MHz radiofrequency radiation (EF) on erythrocyte rheological parameters and erythrocyte zinc levels. Material and Methods: Twenty-four male Wistar Albino rats were randomly grouped as follows: 1) two control groups and 2) study groups: i) Group A: EF exposed group (2.5 h/day for 30 days, the phone on stand-by), and ii) Group B: EF exposed group (2.5 min/day for 30 days, the phone ringing in silent mode). At the end of the experimental period erythrocyte rheological parameters such as erythrocyte deformability and aggregation were determined by an ectacytometer. Erythrocyte zinc level, which affects hemorheological parameters, was also measured by atomic absorption spectrophotometer. Results: Erythrocyte deformability was decreased in both study groups but the decrease in group A was not statistically significant. Exposure to EF did not have any significant effect on erythrocyte aggregation. On the other hand, erythrocyte zinc level was significantly reduced in both study groups. Conclusion: Exposure to EF may have decreased tissue oxygenation due to reduced erythrocyte deformability. Decrease in erythrocyte zinc level may have caused the impairment in erythrocyte deformability.

Erken, Gulten; Kucukatay, Melek Bor; Turgut, Sebahat; Erken, Haydar Ali; Comlekci, Selcuk; Divrikli, Umit; Genc, Osman

2012-01-01

72

Ground level signal strength of electromagnetic waves generated by pulsed electron beams in space  

NASA Astrophysics Data System (ADS)

A theoretical study has been made of the signal strengths at ground level of waves generated by pulsed electron beams in space. The radiated energy is first calculated by an improved version of a theory based on coherent spontaneous emission. This theory evaluates the electric and magnetic field strengths and power fluxes in the far field by applying asymptotic expansion techniques. The power flowing out within a cone whose apex is located at the gun position is calculated, and the intersection of the rays in this cone with the earth's surface is determined by using Snell's law considerations. Ground signal levels are calculated for typical ionospheric conditions as a function of pulsing frequency for fixed beam voltage and for voltage adjusted for resonance between the waves and the particles. For short beams, the ground level signal strengths are relatively insensitive to the wave particle resonance condition, but for longer beams the associated peaking of the signal level begins to be observed. Finally, these results are compared against ambient noise levels to determine under which circumstances these ground signals can be detected.

Harker, K. J.; Neubert, T.; Banks, P. M.; Fraser-Smith, A. C.; Donohue, D. J.

1991-11-01

73

Local Modulation of Double Electromagnetically Induced Transparency Spectrum  

Microsoft Academic Search

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

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

2007-01-01

74

Electromagnetically-induced transparency (EIT) in a four-level atom system  

NASA Astrophysics Data System (ADS)

We prove that the EIT technique can be used for slowing down simultaneously two circularly--left and --right polarized laser pulses (probe fields) in the presence of a linearly polarized laser pulse (coupling field) using a four-level atom system prepared with a weak B-field. The simultaneous quantum interference between the coupling field and each of the two probe fields leads to the formation of a new type of EIT system: a W-system. By turning off one of the two probe fields, a standard EIT behavior can be recognized in two independent V-systems. Our novel EIT technique is applied to ultra-cold Mg atoms in low-lying states (^1S0 -- ground state and ^1P1 -- first excited state). The density matrix formalism is employed for finding coherences between Zeeman levels of the upper ^1P1 state in our W-system. Solving the master equation for a population-trapped four-level atom system and assuming a zero population density on the Zeeman levels of the ^1P1 state give atomic susceptibilities for the dark states associated to the two probe fields. The analysis of the EIT behavior in our W-system is done by varying (1) the Rabi frequencies for the triplet ^1P1 state and (2) the detuning of the two probe lasers. The dependence of the EIT features with the B-field is also discussed.

Nelson, Chris; Bahrim, Cristian

2008-03-01

75

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

76

Analytical method of electromagnetic susceptibility of electronic equipments with enclosure in electric power system at system level  

Microsoft Academic Search

With the development of the power system, protection for the electromagnetic interference is very important. Although protective measures of electronic equipment are improved. But the chassis itself shielded by the existence of defects (such as ventilation holes), leading to the shielding performance decline. In this paper the transmission line matrix method is applied to study electromagnetic signals couple in electronic

Ge Guo; Weidong Zhang; Xiang Cui; Rui Lin

2008-01-01

77

Impact of 900 MHz electromagnetic field exposure on main male reproductive hormone levels: a Rattus norvegicus model  

NASA Astrophysics Data System (ADS)

This work analyzes the effects of radiofrequency-electromagnetic field (RF-EMF) exposure on the reproductive system of male rats, assessed by measuring circulating levels of FSH, LH, inhibin B, activin B, prolactin, and testosterone. Twenty adult male Sprague-Dawley rats (180 ± 10 g) were exposed to 900 MHz RF-EMF in four equal separated groups. The duration of exposure was 1, 2, and 4 h/day over a period of 30 days and sham-exposed animals were kept under the same environmental conditions as the exposed group except with no RF-EMF exposure. Before the exposure, at 15 and 30 days of exposure, determination of the abovementioned hormone levels was performed using ELISA. At the end of the experiment, FSH and LH values of the long time exposure (LTE) group were significantly higher than the sham-exposed group ( p < 0.05). Serum activin B and prolactin in the LTE group showed significant increase and inhibin B showed significant decrease than sham and short time exposed (STE) groups after 30 days RF-EMF exposure ( p < 0.05). Also, a significant decrease in serum testosterone levels in the LTE group was found compared to short and moderate time exposed (MTE) groups after 30 days RF-EMF exposure ( p < 0.05). Results suggest that reproductive hormone levels are disturbed as a result of RF-EMF exposure and it may possibly affect reproductive functions. However, testosterone and inhibin B concentrations as a fertility marker and spermatogenesis were decreased significantly.

Sepehrimanesh, Masood; Saeb, Mehdi; Nazifi, Saeed; Kazemipour, Nasrin; Jelodar, Gholamali; Saeb, Saeedeh

2014-09-01

78

Impact of 900 MHz electromagnetic field exposure on main male reproductive hormone levels: a Rattus norvegicus model.  

PubMed

This work analyzes the effects of radiofrequency-electromagnetic field (RF-EMF) exposure on the reproductive system of male rats, assessed by measuring circulating levels of FSH, LH, inhibin B, activin B, prolactin, and testosterone. Twenty adult male Sprague-Dawley rats (180?±?10 g) were exposed to 900 MHz RF-EMF in four equal separated groups. The duration of exposure was 1, 2, and 4 h/day over a period of 30 days and sham-exposed animals were kept under the same environmental conditions as the exposed group except with no RF-EMF exposure. Before the exposure, at 15 and 30 days of exposure, determination of the abovementioned hormone levels was performed using ELISA. At the end of the experiment, FSH and LH values of the long time exposure (LTE) group were significantly higher than the sham-exposed group (p?levels in the LTE group was found compared to short and moderate time exposed (MTE) groups after 30 days RF-EMF exposure (p?levels are disturbed as a result of RF-EMF exposure and it may possibly affect reproductive functions. However, testosterone and inhibin B concentrations as a fertility marker and spermatogenesis were decreased significantly. PMID:24357488

Sepehrimanesh, Masood; Saeb, Mehdi; Nazifi, Saeed; Kazemipour, Nasrin; Jelodar, Gholamali; Saeb, Saeedeh

2014-09-01

79

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

PubMed

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

Korytár, R; Schmitteckert, P

2013-11-27

80

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  

NASA Astrophysics Data System (ADS)

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.

Ponds, C. D.

1985-01-01

81

Extraction of nuclear level densities from neutron spectra emitted in proton-induced reactions on lead isotopes and Bi  

NASA Astrophysics Data System (ADS)

Neutron-production spectra from (p,n) reactions on 204,206,207,208Pb and 209Bi measured previously by a Russian group were analyzed to extract numerical values for the level densities of the residual nuclei up to excitation energies of 5-6 MeV with uncertainties of 20-50%. Comparisons with the Gilbert-Cameron form and various parametrizations of the Ignatyuk formulation indicate that the Ignatyuk model with original parameters describes the results well whereas the other forms yield lower level densities. The agreement with the results of the first analysis by the experimenters themselves varies over the range of nuclei considered, being poorest for 204,206Bi.

Wallner, A.; Strohmaier, B.; Vonach, H.

1995-02-01

82

Use of pupil size to determine the effect of electromagnetic acupuncture on activation level of the autonomic nervous system.  

PubMed

Magnetic fields are widely considered as a method of treatment to increase the therapeutic effect when applied to acupoints. Hence, this study proposes a new method which creates significant stimulation of acupoints by using weak magnetic fields. We conducted this experiment in order to confirm the effect on the activation level of the autonomic nervous system by measuring pupil sizes in cases of stimulation by using manual acupuncture and electromagnetic acupuncture (EMA) at BL15. We selected 30 Hz of biphasic wave form with 570.1 Gauss. To confirm the biopotential by the magnetic flux density occurring in EMA that affected the activation of the autonomic nervous system, we observed the biopotential induced at the upper and the mid left and right trapezius. We observed a significant decrease in pupil size only in the EMA group (p < 0.05), thus confirming that EMA decreased the pupil size through activation of the parasympathetic nerve in the autonomic nervous system. Moreover, we confirmed that the amplitude of the biopotential which was caused by 570.1 Gauss was higher than ±20 ?A. Thus, we can conclude that EMA treatment successfully activates the parasympathetic nerve in the autonomic nervous system by inducing a biotransformation by the induced biopotential. PMID:24929456

Kim, Soo-Byeong; Choi, Woo-Hyuk; Liu, Wen-Xue; Lee, Na-Ra; Shin, Tae-Min; Lee, Yong-Heum

2014-06-01

83

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

84

Analysis of High Cadence In Situ Solar Wind Ionic Composition Data Using Wavelet Power Spectra Confidence Levels  

NASA Astrophysics Data System (ADS)

The variability inherent in solar wind composition has implications for the variability of the physical conditions in its coronal source regions, providing constraints on models of coronal heating and solar wind generation. We present a generalized prescription for constructing a wavelet power significance measure (confidence level) for the purpose of characterizing the effects of missing data in high cadence solar wind ionic composition measurements. We describe the data gaps present in the 12 minute Advanced Composition Explorer/Solar Wind Ionic Composition Spectrometer observations of O7 +/O6 + during 2008. The decomposition of the in situ observations into "good measurement" and "no-measurement" signals allows us to evaluate the performance of a filler signal, i.e., various prescriptions for filling the data gaps. We construct Monte Carlo simulations of synthetic O7 +/O6 + composition data and impose the actual data gaps that exist in the observations in order to investigate two different filler signals: one, a linear interpolation between neighboring good data points, and two, the constant mean value of the measured data. Applied to these synthetic data plus filler signal combinations, we quantify the ability of the power spectra significance level procedure to reproduce the ensemble-averaged time-integrated wavelet power per scale of an ideal case, i.e., the synthetic data without imposed data gaps. Finally, we present the wavelet power spectra for the O7 +/O6 + data using the confidence levels derived from both the mean value and linear interpolation data gap filling signals and discuss the results.

Edmondson, J. K.; Lynch, B. J.; Lepri, S. T.; Zurbuchen, T. H.

2013-12-01

85

Electromagnetic Spectrum from QGP Fluid  

E-print Network

We calculate thermal photon and electron pair distribution 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 the source particles on the electromagnetic spectra.

T. Hirano; S. Muroya; M. Namiki

1997-08-29

86

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

87

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

NASA Astrophysics Data System (ADS)

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

Philbin, M. Kathleen; Evans, Jack B.

2003-10-01

88

Optical spectra, energy levels, and emission intensity calculations of trivalent thulium ions in gadolinium scandium gallium garnet  

NASA Astrophysics Data System (ADS)

Absorption spectra of trivalent thulium ions in gadolinium scandium gallium garnet are reported between 1.9 and 0.25 ?m at 4 K. Laser-induced fluorescence was observed at 4 K from the 1D2, 1G4, and 3H4 (4 and 300 K) manifolds. Site-selective excitation experiments reveal large fractions of thulium ions in both regular D2 sites and alternate sites. A crystal-field splitting calculation was carried out in which a parameterized Hamiltonian (including Coulombic, spin-orbit, and crystal-field terms in D2 symmetry) was diagonalized for all multiplet manifolds of the Tm3+ (4f12) configuration. The rms deviation between 56 experimental and calculated Stark levels was 10 cm-1. Calculations were carried out to predict branching ratios for emission from the 3H4 manifold to the 3H5, 3F4, and 3H6 manifolds, as well as line-to-line transition probabilities for transitions between the 3H4 manifold and the 3H5 manifold.

Seltzer, Michael D.; Gruber, John B.; Rosenblatt, Gregg H.; Morrison, Clyde A.; Filer, Elizabeth D.

1994-01-01

89

The Complex Core Level Spectra of CeO2: An Analysis in Terms of Atomic and Charge Transfer Effects  

SciTech Connect

We present a rigorous parameter-free theoretical treatment of the Ce 4s and 5s photoelectron spectra of CeO2. In the currently accepted model the satellite structure in the photoelectron spectra is explained in terms of a mixed valence (Ce 4f0 O 2p6, Ce 4f1 O 2p5, and Ce 4f2 O 2p4) con?guration. We show that charge transfer (CT) into Ce 5d as well as con?gurations involving intra-atomic movement of charge must be considered in addition and compute their contributions to the spectra.

Bagus, Paul S.; Nelin, Constance J.; Ilton, Eugene S.; Baron, Martin; Abbott, Heather; Primorac, Elena; Kuhlenbeck, Helmut; Shaikhutdinov, Shamil; Freund, Hans-Joachim

2010-03-05

90

NMR spectra of transient radicals  

SciTech Connect

A time-resolved method for the study of structure and spin dynamics of transient radicals in liquids is described. Pulsed electron beam or pulsed laser irradiation is used to create transient radicals in solution. Irradiation is carried out in the field of a variable electromagnet, and the diamagnetic products are transferred rapidly using a fast flow system to an NMR probe. During the radical reaction, a 0.5 to 10 ..mu..s rf pulse is applied to the reacting sample at an appropriate frequency, corresponding to a nuclear energy level spacing of the given radical. Nuclear spin level population changes in the radical are transferred to its reaction product and detected as intensity changes in their NMR spectra. The method is illustrated using radiolyzed sodium malonate.

Trifunac, A.D.; Chiu, T.M.; Nuttall, R.H.D.

1984-01-01

91

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

92

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

93

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.

94

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

95

Optomechanical analog of two-color electromagnetically induced transparency: Photon transmission through an optomechanical device with a two-level system  

NASA Astrophysics Data System (ADS)

Some optomechanical systems can be transparent to a probe field when a strong driving field is applied. These systems can provide an optomechanical analog of electromagnetically induced transparency (EIT). We study the transmission of a probe field through a hybrid optomechanical system consisting of a cavity and a mechanical resonator with a two-level system (qubit). The qubit might be an intrinsic defect inside the mechanical resonator, a superconducting artificial atom, or another two-level system. The mechanical resonator is coupled to the cavity field via radiation pressure and to the qubit via the Jaynes-Cummings interaction. We find that the dressed two-level system and mechanical phonon can form two sets of three-level systems. Thus, there are two transparency windows in the discussed system. We interpret this effect as an optomechanical analog of two-color EIT (or double EIT). We demonstrate how to switch between one and two EIT windows by changing the transition frequency of the qubit. We show that the absorption and dispersion of the system are mainly affected by the qubit-phonon coupling strength and the transition frequency of the qubit.

Wang, Hui; Gu, Xiu; Liu, Yu-xi; Miranowicz, Adam; Nori, Franco

2014-08-01

96

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 range 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 innovative 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.

2014-03-01

97

Electromagnetic Math  

NSDL National Science Digital Library

This book offers an introduction to the electromagnetic spectrum using examples of data from a variety of NASA missions and satellite technologies. The 84 problem sets included allow students to explore the concepts of waves, wavelength, frequency, and speed; the Doppler Shift; light; and the energy carried by photons in various bands of the spectrum. Extensive background information is provided which describes the nature of electromagnetic radiation.

98

Classical analogs of double electromagnetically induced transparency  

NASA Astrophysics Data System (ADS)

Double electromagnetically induced transparency (DEIT) in a four-level atomic system with tripod-type energy-level configuration is modeled by using two classical systems. The first is a set of three coupled harmonic oscillators subject to frictional forces and external drives and the second is a set of three coupled RLC circuits with electric resistors and alternating voltage sources. It is shown that both of the two classical systems have absorption spectra of DEIT similar to that of the four-level tripod-type atomic system. These classical analogies provide simple and intuitive physical description of quantum interference processes and can be used to illustrate experimental observations of the DEIT in quantum systems.

Bai, Zhengyang; Hang, Chao; Huang, Guoxiang

2013-03-01

99

Importance of nuclear triaxiality for electromagnetic strength, level density and neutron capture cross sections in heavy nuclei  

E-print Network

Cross sections for neutron capture in the range of unresolved resonances are predicted simultaneously to level distances at the neutron threshold for more than 100 spin-0 target nuclei with A >70. Assuming triaxiality in nearly all these nuclei a combined parameterization for both, level density and photon strength is presented. The strength functions used are based on a global fit to IVGDR shapes by the sum of three Lorentzians adding up to the TRK sum rule and theory-based predictions for the A-dependence of pole energies and spreading widths. For the small spins reached by capture level densities are well described by only one free global parameter; a significant collective enhancement due to the deviation from axial symmetry is observed. Reliable predictions for compound nuclear reactions also outside the valley of stability as expected from the derived global parameterization are important for nuclear astrophysics and for the transmutation of nuclear waste.

Eckart Grosse; Arnd R. Junghans; Ralph Massarczyk

2014-01-05

100

Importance of nuclear triaxiality for electromagnetic strength, level density and neutron capture cross sections in heavy nuclei  

E-print Network

Cross sections for neutron capture in the range of unresolved resonances are predicted simultaneously to level distances at the neutron threshold for more than 100 spin-0 target nuclei with A >70. Assuming triaxiality in nearly all these nuclei a combined parameterization for both, level density and photon strength is presented. The strength functions used are based on a global fit to IVGDR shapes by the sum of three Lorentzians adding up to the TRK sum rule and theory-based predictions for the A-dependence of pole energies and spreading widths. For the small spins reached by capture level densities are well described by only one free global parameter; a significant collective enhancement due to the deviation from axial symmetry is observed. Reliable predictions for compound nuclear reactions also outside the valley of stability as expected from the derived global parameterization are important for nuclear astrophysics and for the transmutation of nuclear waste.

Grosse, Eckart; Massarczyk, Ralph

2014-01-01

101

[FTIR spectra investigation of rat sensitive tissues exposure to ELF-EMF].  

PubMed

Nonthermal effects of extremely low frequency electromagnetic fields (ELF-EMF) are related to changes in the microstructure of biological tissues after exposure to electromagnetic radiation. Fourier transform infrared spectroscopy (FTIR) analysis method can effectively study the mechanisms of biological effects of electromagnetic radiation. The present paper studies the characteristics of sensitive tissues of rat after ELF-EMF exposure. FTIR analysis of sensitive tissues of control group and experimental group showed that 50 Hz, 0.75 mT ELF-EMF exposure for 20 days can affect molecular level of the rat testis, blood and brain. Experimental results show that regular changes in absorption peak positions and intensity in the spectra of sensitive tissue may be caused by exposure to ELF-EMF, therefore, Fourier transform infrared spectroscopy is an effective means to study mechanism of biological effects of electromagnetic fields. PMID:22827052

Li, Gun; Yan, Ya-jing; Huang, Yong; Zhou, Yan; Pang, Xiao-feng

2012-05-01

102

The role of Rydberg and continuum levels in computing high harmonic generation spectra of the hydrogen atom using time-dependent configuration interaction  

SciTech Connect

We study the role of Rydberg bound-states and continuum levels in the field-induced electronic dynamics associated with the High-Harmonic Generation (HHG) spectroscopy of the hydrogen atom. Time-dependent configuration-interaction (TD-CI) is used with very large atomic orbital (AO) expansions (up to L= 4 with sextuple augmentation and off-center functions) to describe the bound Rydberg levels, and some continuum levels. To address the lack of ionization losses in TD-CI with finite AO basis sets, we employed a heuristic lifetime for energy levels above the ionization potential. The heuristic lifetime model is compared against the conventional atomic orbital treatment (infinite lifetimes), and a third approximation which is TD-CI using only the bound levels (continuum lifetimes go to zero). The results suggest that spectra calculated using conventional TD-CI do not converge with increasing AO basis set size, while the zero lifetime and heuristic lifetime models converge to qualitatively similar spectra, with implications for how best to apply bound state electronic structure methods to simulate HHG. The origin of HHG spectral features including the cutoff and extent of interference between peaks is uncovered by separating field-induced coupling between different types of levels (ground state, bound Rydberg levels, and continuum) in the simulated electronic dynamics. Thus the origin of deviations between the predictions of the semi-classical three step model and the full simulation can be associated with particular physical contributions, which helps to explain both the successes and the limitations of the three step model.

Luppi, Eleonora [Laboratoire de Chimie Théorique, Université Pierre et Marie Curie, 75005 Paris (France)] [Laboratoire de Chimie Théorique, Université Pierre et Marie Curie, 75005 Paris (France); Head-Gordon, Martin [Department of Chemistry, University of California, Berkeley, California 94720, USA and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)] [Department of Chemistry, University of California, Berkeley, California 94720, USA and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2013-10-28

103

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

104

Absorption spectra and energy levels of Gd3+, Nd3+, and Cr3+ in the garnet Gd3Sc2Ga3O12  

NASA Astrophysics Data System (ADS)

Absorption spectra measured between 0.3 and 6.7 ?m are reported for Gd3+, Nd3+, and Cr3+ in single-crystal gadolinium scandium gallium garnet, Gd3Sc2Ga3O12, at various temperatures. Energy levels split by the crystal field are identified between 1500 and 35 000 cm-1 for Gd3+(4f7), Nd3+(4f3), and Cr3+(3d3). The rare-earth ions occupy sites of D2 point-group symmetry, and chromium ions are found primarily in sites of C3i point-group symmetry. A Hamiltonian consisting of Coulombic, spin-orbit, and crystal-field terms is diagonalized to obtain theoretical energy levels for each symmetry. Empirical crystal-field parameters Bkm were determined by fitting calculated energy levels to observed levels through a variation of the Bkm; these were compared with a lattice-sum calculation. The rms deviations between calculated and observed levels are 1.7 cm-1 for Nd3+ (45 levels), 4.0 cm-1 for Gd3+ (14 levels), and 87.7 cm-1 for Cr3+ (35 levels).

Gruber, John B.; Hills, Marian E.; Morrison, Clyde A.; Turner, Gregory A.; Kokta, Milan R.

1988-05-01

105

What Are Electromagnetic Fields?  

MedlinePLUS

... GHz. The effects of electromagnetic fields on the human body depend not only on their field level but on their frequency and energy. Our electricity power supply and all appliances using electricity are the main sources of ELF fields; computer screens, anti-theft devices and security systems are ...

106

Absorption spectra and energy levels of Gd(3+), Nd(3+) and Cr(3+) in the garnet Gd3Sc2Ga3O12  

NASA Astrophysics Data System (ADS)

Absorption spectra recorded between 0.3 and 6.7 microns are reported for trivalent gadolinium, trivalent neodymium, and trivalent chromium in single-crystal gadolinium scandium gallium garnet, Gd3Sc2Ga3O12, at liquid nitrogen and room temperatures. Crystalline electric-field-split energy levels are established from data between 1,5000 and 35,000/cm for Gd3+ (4f7), Nd3+ (4f3), and Cr3+ (3d3). The Gd3+ and Nd3+ ions occupy sites having D2 point symmetry; Cr3+ ions are found primarily in sites of C3i point symmetry. A Hamiltonian consisting of Coulombic, spin-orbit, and crystalline electric-field terms, having symmetry appropriate to each ion, is diagonalized to obtain theoretic energy levels. The rms deviation between calculated and observed levels for Nd3+ (with 45 levels) is 1.7/cm, for Gd3+ (with 14 levels) is 4/cm, and for Cr3+ (with 35 levels) is 87.7/cm. A lattice sum calculation is compared with the phenomenological parameters obtained from fitting the observed energy levels.

Gruber, John B.; Hills, Marian E.; Morrison, Clyde A.; Turner, Gregory A.; Kokta, Milar R.

1988-03-01

107

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

108

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

109

Local field effects and multi-peak spectra in coherent scattering of resonant light in a two-level medium  

Microsoft Academic Search

Scattering of a laser pulse is considered in a dense medium with account for local field effects. The interacting system of\\u000a two-level atoms and quantized field modes is studied in the second Born approximation of the Bogolyubov-Born-Green-Kirkwood-Yvon\\u000a hierarchy of equations for reduced density and correlation operators. The local field correction is derived consistently from\\u000a the conventional interaction Hamiltonian and adjusted

Maxim G. Gladllsh; Alexey A. Panteleev; Vladimir K. Roerich

2006-01-01

110

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

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

111

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

SciTech Connect

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

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

1999-12-15

112

Simulation of the temperature elevation in children exposed to plane wave electromagnetic fields (10 MHz-1 GHz) at the ICNIRP reference level.  

PubMed

Because of a lack of thermal models, to date, limitation of exposure to an electromagnetic field (EMF) has been based on restricting intracorporal specific absorption rates. To allow convenient compliance checks, reference field values have been defined. If they are met, compliance with basic restrictions is assumed. This article demonstrates that this assumption is not valid in every case. It has therefore been investigated as to whether the biological goal of limiting tissue heating is still met, in particular with regard to children. The thermal solver applied is based on the bioheat equation, with implemented additional improvements that allow consideration of blood flow and metabolic rate as a function of local tissue temperature rise and, in addition, adapt the blood temperature relative to the absorbed power. As a further improvement, heat exchange at the tissue/air boundary has been modeled, with radiation, convection, and sweating considered as well. The mathematical equations describing these additional thermoregulatory mechanisms were taken from the literature and unified in the thermoregulatory model used for this study. For the investigated case of plane wave exposure, the results confirm the violation of the basic restrictions in five of the six models when exposed to reference EMF levels. However, using thermal modeling, it was possible to demonstrate that heating remained within the biological tolerances. In particular, temperature elevation of the body core temperature remained <0.014°C and the local peak temperature did not exceed 1°C. PMID:22691427

Niedermayr, Florian; Leitgeb, Norbert; Siegl, Werner

2012-06-01

113

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

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

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

116

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

117

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

118

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

119

Analytical method of spectra calculations in the Bargmann representation  

NASA Astrophysics Data System (ADS)

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.

Maciejewski, Andrzej J.; Przybylska, Maria; Stachowiak, Tomasz

2014-10-01

120

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

121

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

122

ECE 203 Spring 2012 Engineering Electromagnetics Waves (3)  

E-print Network

ECE 203 ­ Spring 2012 Engineering Electromagnetics Waves (3) Lecture Time: Spring 2012, Monday, and A. S. Inan, Electromagnetic Waves, Prentice Hall (2000). Useful EM textbook for ECE 203-level. 2. D. Morgenthaler, J. A. Kong, Electromagnetic Waves, Prentice Hall (1994). Useful textbook for ECE 203-level

Gilchrist, James F.

123

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

2014-06-19

124

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

125

Atomic Spectra  

NSDL National Science Digital Library

This well-illustrated page from Hyperphysics contains the light emitted by several elements and their respective spectra as well. 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.

2007-12-20

126

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.

127

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

128

atomic spectra 1 Atomic Spectra  

E-print Network

. Eisberg and Resnick: Quantum Physics of Atoms, Molecules, Solids, Nuclei and Particles, pp. 95-119, p286 Physics, pp. 88-93 (Rutherford nuclear model), 93-106 (atomic structure and electron spectra) 2. D. W. Preston and E. R. Dietz: The Art of Experimental Physics, pp. 397- 399, resolution of optical instruments

Glashausser, Charles

129

SPECTRA: the sensor and its mission  

Microsoft Academic Search

The SPECTRA system will allow to achieve the scientific objectives by observing defined land targets in various spectral bands of the optical range of the electromagnetic spectrum from the Visible into the Thermal Infrared and with variable directions of observations. These observation capabilities are intended to provide a sampling of the Bi-directional Reflectance Distribution Function (BRDF) of the vegetation objects

U. del Bello

2002-01-01

130

Preliminary Spectroscopic Measurements for a Gallium Electromagnetic (GEM) Thruster  

NASA Technical Reports Server (NTRS)

As a propellant option for electromagnetic thrusters, liquid ,gallium appears to have several advantages relative to other propellants. The merits of using gallium in an electromagnetic thruster (EMT) are discussed and estimates of discharge current levels and mass flow rates yielding efficient operation are given. The gallium atomic weight of 70 predicts high efficiency in the 1500-2000 s specific impulse range, making it ideal for higher-thrust, near-Earth missions. A spatially and temporally broad spectroscopic survey in the 220-520 nm range is used to determine which species are present in the plasma and estimate electron temperature. The spectra show that neutral, singly, and doubly ionized gallium species are present in a 20 J, 1.8 kA (peak) are discharge. With graphite present on the insulator to facilitate breakdown, singly and doubly ionized carbon atoms are also present, and emission is observed from molecular carbon (CZ) radicals. A determination of the electron temperature was attempted using relative emission line data, and while the spatially and temporally averaged, spectra don't fit well to single temperatures, the data and presence of doubly ionized gallium are consistent with distributions in the 1-3 eV range.

Thomas, Robert E.; Burton, Rodney L.; Glumac, Nick G.; Polzin, Kurt A.

2007-01-01

131

Power electronics and electromagnetic compatibility  

Microsoft Academic Search

Recently, power electronics has become the dominant factor in the deterioration of the electromagnetic environment, causing declining quality of line power and increasing level of conducted EMI. This paper reviews the fundamentals of EMC in power electronics, including the terminology and categories of EMC, the propagation and generation of low-frequency and high-frequency disturbances, and the various agency regulations. The paper

R. Redl

1996-01-01

132

Skyglow effects in UV and visible spectra: Radiative fluxes  

NASA Astrophysics Data System (ADS)

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

Kocifaj, Miroslav; Solano Lamphar, Hector Antonio

2013-09-01

133

Skyglow effects in UV and visible spectra: radiative fluxes.  

PubMed

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

Kocifaj, Miroslav; Solano Lamphar, H A

2013-09-30

134

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

135

Action of an electromagnetic pulse on a plasma with a high level of ion-acoustic turbulence. Field diffusion and subdiffusion  

SciTech Connect

Specific features of the interaction of a relatively weak electromagnetic pulse with a nonisothermal current-carrying plasma in which the electron drift velocity is much higher than the ion-acoustic velocity, but lower than the electron thermal velocity, are studied. If the state of the plasma with ion-acoustic turbulence does not change during the pulse action, the field penetrates into the plasma in the ordinary diffusion regime, but the diffusion coefficient in this case is inversely proportional to the anomalous conductivity. If, during the pulse action, the particle temperatures and the current-driving field change due to turbulent heating, the field penetrates into the plasma in the subdiffusion regime. It is shown how the presence of subdiffusion can be detected by measuring the reflected field.

Ovchinnikov, K. N.; Uryupin, S. A., E-mail: uryupin@sci.lebedev.ru [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)

2013-09-15

136

The Classification of Transitions between Levels of Principal Quantum Numbers 2 and 3 in S X to XIV and of Isoelectronic Spectra in P, Cl and Ar  

Microsoft Academic Search

Emission lines which result from transitions betwen principal quantum numbers 2 and 3 in S X to XIV P X to XII, Cl XI to XIV and Ar XII and XIII are classified. The spectra were emitted from the plasma produced in a theta-pinch into which a small quantity of hydrogen sulphide, phosphine, chlorine or argon was added. Wavelength measurements

B C Fawcett; R W Hayes

1973-01-01

137

Investigation of electromagnetic welding  

E-print Network

We propose several methodologies to study and optimize the electromagnetic process for Electromagnetic Forming (EMF) and Welding (EMW), thereby lowering the necessary process energy up to a factor of three and lengthening ...

Pressl, Daniel G. (Daniel Gerd)

2009-01-01

138

The Electromagnetic Spectrum  

NSDL National Science Digital Library

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

Astrophysics, Laboratory F.

2004-11-17

139

Electromagnetic Field Exposure Dosimeter.  

National Technical Information Service (NTIS)

The growing concern about adverse health effects caused by electromagnetic radiation prompted the ideas for this dosimeter. Data have been presented that ink prolonged exposure to electromagnetic radiation from power lines to leukemia and some types of ca...

A. C. Feaga, M. P. Hilliard, R. Link

1994-01-01

140

Shape optimization of electromagnet  

Microsoft Academic Search

The paper deals with finding the optimal shape of the electromagnet by changing skew keeper and skew pole shoe of the electromagnet so as to obtain maximum tensile force. The solution used numerical methods, especially the program COMSOL.

S. Zajaczek; L. Skr?iva?nek; L. Iva?nek

2010-01-01

141

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

142

Electromagnetic Interference (Emi)  

Microsoft Academic Search

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

Mike Hardage; Philip D. Henry

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

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

145

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

146

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

147

Steps Towards a Fully Automated Classification and Redshift-measurement Pipeline for LAMOST Spectra. I. Continuum level and wavelength estimation for galaxies  

Microsoft Academic Search

The Large Sky-Area Multi-Object Spectroscopic Telescope (LAMOST) under construction by the National Astronomical Observatories will yield up to four thousand multi-fiber spectra of stars and galaxies per field. The present series of papers describes the automated data-reduction pipeline currently being designed in order to cope with the anticipated flood of spectrographic data. In this preliminary paper, we present an automated

A.-Li Luo; Yong-Heng Zhao

2001-01-01

148

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-Vinas, David; Verdugo-Diaz, Leticia

2007-01-01

149

Electromagnetic environmental criteria for US Army missile systems - EMC, EMR, EMI, EMP, ESD, and lightning  

NASA Astrophysics Data System (ADS)

This paper 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.

Ponds, Charles D.; Knaur, James A.

1988-01-01

150

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

151

Coherent metallic screening in core-level photoelectron spectra for the strongly correlated oxides La1-xBaxMnO3 and V1-xWxO2  

NASA Astrophysics Data System (ADS)

Coherent metallic screening structures shown in core-level photoemission spectra for strongly correlated oxide materials were studied by hard x-ray photoemission spectroscopy (HAXPES) and the configuration interaction (CI) theory based on the cluster model, including the coherent metallic screening process. For the La1-xBaxMnO3 thin film, the normalized intensity of the coherent metallic screening structure (IS) seen in the Mn 2p core-level spectra was proportional to the square of the hybridization strength, (V*)2, between the transition metal 3d and coherent metallic states. In contrast, the normalized IS seen in the V 2p core-level spectra for the V1-xWxO2 thin film was not proportional to (V*)2. The different behaviors of the normalized IS for the La1-xBaxMnO3 and V1-xWxO2 thin films as a function of V* were understood by the series of the CI cluster model calculation. From the CI cluster model calculation, we found that the charge transfer energy (?*) between the transition metal 3d states and the coherent metallic states strongly affect the normalized IS in the 2p core-level photoemission final states. Therefore, the behavior of the normalized IS in the 2p core-level HAXPES is thus not simply explained by the change of V*. The electronic structure parameters such as ?* and V* relating to the coherent metallic states strongly contribute to the variation of the normalized IS in the photoemission final states. In contrast, we found that the detailed IS evaluation in the core-level HAXPES experiments for materials, in which the coherent metallic screening structures appear, allows us to evaluate the value of V* when we have the experimental core-level spectra and the electronic structure parameters set for a reference material. We also found that the intensity at the Fermi level is proportional to (V*)2, as expected from the Anderson impurity model.

Ueda, S.; Takami, H.; Kanki, T.; Tanaka, H.

2014-01-01

152

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

153

Genetic Effects of Electromagnetic Waves  

NASA Astrophysics Data System (ADS)

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

Aroutiounian, Rouben; Hovhannisyan, Galina; Gasparian, Gennady

154

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.

Research Experience for Teachers (RET) Program, Center of Advancement of Engineering Fibers and Films,

155

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

156

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.

157

Susceptibility of Civilian GPS Receivers to Electromagnetic Radiation  

Microsoft Academic Search

Civilian handheld global positioning system receivers were tested for their susceptibility against radiated electromagnetic disturbances of different characteristics and field levels. This susceptibility data were compared to the existing electromagnetic compatibility (EMC) immunity requirements for electronic devices. Some of the receivers were disrupted by continues waves at in- as well as out-of-band frequencies, at field levels far below the existing

D. Mansson; R. Thottappillil; T. Nilsson; O. Lunden; M. Backstrom

2008-01-01

158

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

159

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

160

Electromagnetic compatibility overview  

NASA Technical Reports Server (NTRS)

An assessment of the electromagnetic compatibility impact of the Satellite Power System is discussed. The discussion is divided into two parts: determination of the emission expected from SPS including their spatial and spectral distributions, and evaluation of the impact of such emissions on electromagnetic systems including considerations of means for mitigating effects.

Davis, K. C.

1980-01-01

161

Tunability enhanced electromagnetic wiggler  

DOEpatents

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

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

1992-01-01

162

Tunability enhanced electromagnetic wiggler  

DOEpatents

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

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

1992-03-24

163

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.

164

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.

165

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

166

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

167

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

168

On-Chip Transient Detection Circuit for System-Level ESD Protection in CMOS Integrated Circuits to Meet Electromagnetic Compatibility Regulation  

Microsoft Academic Search

A new on-chip transient detection circuit for system-level electrostatic discharge (ESD) protection is proposed. The circuit performance to detect different positive and negative fast electrical transients has been investigated by the HSPICE simulator and verified in a silicon chip. The experimental results in a 0.13-m CMOS integrated circuit (IC) have confirmed that the proposed on-chip transient detection circuit can be

Ming-Dou Ker; Cheng-Cheng Yen; Pi-Chia Shih

2008-01-01

169

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

170

Electromagnetic conic sections Tevian Draya)  

E-print Network

Electromagnetic conic sections Tevian Draya) Department of Mathematics, Oregon State University electromagnetic conic sections. We then give a necessary and sufficient condition for a given vector field

171

Electromagnetic fluctuations and normal modes of a drifting relativistic plasma  

SciTech Connect

We present an exact calculation of the power spectrum of the electromagnetic fluctuations in a relativistic equilibrium plasma described by Maxwell-Jüttner distribution functions. We consider the cases of wave vectors parallel or normal to the plasma mean velocity. The relative contributions of the subluminal and supraluminal fluctuations are evaluated. Analytical expressions of the spatial fluctuation spectra are derived in each case. These theoretical results are compared to particle-in-cell simulations, showing a good reproduction of the subluminal fluctuation spectra.

Ruyer, C.; Gremillet, L.; Bénisti, D. [CEA, DAM, DIF, F-91297 Arpajon (France)] [CEA, DAM, DIF, F-91297 Arpajon (France); Bonnaud, G. [CEA, Saclay, INSTN, F-91191 Gif-sur-Yvette (France)] [CEA, Saclay, INSTN, F-91191 Gif-sur-Yvette (France)

2013-11-15

172

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.

173

Reflectance spectra of primitive chondrites  

NASA Astrophysics Data System (ADS)

We are studying a wide sample of pristine carbonaceous chondrites from the NASA Antarctic collection in order to get clues on the physico-chemical processes occurred in the parent bodies of these meteorites. We are obtaining laboratory reflectance spectra of different groups of carbonaceous chondrites, but here we focus in CM and CI chondrites. We discuss the main spectral features that can be used to identify primitive carbonaceous asteroids by remote sensing techniques. Two different spectrometers were used covering the entire 0.3 to 30 ?m electromagnetic window. Only a handful of Near Earth Objects (NEOs) exhibit bands or features clearly associated with aqueous alteration. Among them are the target asteroids of Osiris Rex and Marco Polo-R missions.

Trigo-Rodríguez, J. M.; Moyano-Cambero, C. E.; Llorca, J.

2013-05-01

174

Rovibrational spectra of DCF3 in the 2000 cm-1 region: A high-resolution study of the v5 = 2 and v2 = v5 = 1 levels  

NASA Astrophysics Data System (ADS)

The high-resolution infrared spectrum of DCF3 was investigated in the 2000 cm-1 region, with the aim of assigning and analyzing the overtone bands 2?5 (A1 + E), as well as the combination band ?2 + ?5 (E). The present paper reports on the first high-resolution study of the v2 = v5 = 1 and v5 = 2 levels, through the analysis of the combination ?2 + ?5 and the overtone 2 ?5?2 bands respectively. This analysis can be thought of as a necessary step toward the reinvestigation of the complicated vibrational pattern in the CD stretching fundamental region.

Ceausu-Velcescu, Adina; Pracna, Petr; Predoi-Cross, Adriana

2014-11-01

175

Electromagnetic Abdulaziz Hanif  

E-print Network

of these wire strands will be wrapped into a cable. This electromagnet is then super-cooled with liquid helium are better conductors and have a greater effect on the magnetic field. The plate would be charged up

Masoudi, Husain M.

176

The Electromagnetic Spectrum  

NSDL National Science Digital Library

This interactive, online module reviews the basics of the the electromagnetic spectrum and makes the connection between radiation theory and the images we get from weather satellites. Students will learn about: the electromagnetic spectrum; electromagnetic waves; the electromagnetic spectrum and radiation theory; and how satellite radiometers "see" different sections of the spectrum. The module is part of an online course for grades 7-12 in satellite meteorology, which includes 10 interactive modules. The site also includes lesson plans developed by teachers and links to related resources. Each module is designed to serve as a stand-alone lesson, however, a sequential approach is recommended. Designed to challenge students through the end of 12th grade, middle school teachers and students may choose to skim or skip a few sections.

177

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

178

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

179

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

180

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

181

Concurrent electromagnetic scattering analysis  

NASA Technical Reports Server (NTRS)

The computational power of the hypercube parallel computing architecture is applied to the solution of large-scale electromagnetic scattering and radiation problems. Three analysis codes have been implemented. A Hypercube Electromagnetic Interactive Analysis Workstation was developed to aid in the design and analysis of metallic structures such as antennas and to facilitate the use of these analysis codes. The workstation provides a general user environment for specification of the structure to be analyzed and graphical representations of the results.

Patterson, Jean E.; Cwik, Tom; Ferraro, Robert D.; Jacobi, Nathan; Liewer, Paulett C.; Lockhart, Thomas G.; Lyzenga, Gregory A.; Parker, Jay

1989-01-01

182

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

183

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

NASA Astrophysics Data System (ADS)

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

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

2013-01-01

184

A remote sensor for electromagnetic personal safety monitoring  

Microsoft Academic Search

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

K. Pillet; F. Buesink; F. Leferink

2006-01-01

185

Degree Spectra of Alexandra A.  

E-print Network

Degree Spectra of Structures Alexandra A. Soskova DEGREE SPECTRA OF STRUCTURES CO-SPECTRA OF STRUCTURES PROPERTIES OF THE DEGREE SPECTRA AND CO-SPECTRA RELATIVE SPECTRA OF STRUCTURES PROPERTIES OF RELATIVE SPECTRA Degree Spectra of Structures Alexandra A. Soskova Faculty of Mathematics and Computer

Haase, Markus

186

Night Spectra Quest.  

ERIC Educational Resources Information Center

Presents the Night Spectra Quest, a pocket-sized chart that identifies in color the spectra of all the common night lights and has an integrally mounted, holographic diffraction grating to look through. (JRH)

Jacobs, Stephen

1995-01-01

187

Electromagnetic attachment mechanism  

NASA Technical Reports Server (NTRS)

An electromagnetic attachment mechanism is disclosed for use as an end effector of a remote manipulator system. A pair of electromagnets, each with a U-shaped magnetic core with a pull-in coil and two holding coils, are mounted by a spring suspension system on a base plate of the mechanism housing with end pole pieces adapted to move through openings in the base plate when the attractive force of the electromagnets is exerted on a strike plate of a grapple fixture affixed to a target object. The pole pieces are spaced by an air gap from the strike plate when the mechanism first contacts the grapple fixture. An individual control circuit and power source is provided for the pull-in coil and one holding coil of each electromagnet. A back-up control circuit connected to the two power sources and a third power source is provided for the remaining holding coils. When energized, the pull-in coils overcome the suspension system and air gap and are automatically de-energized when the pole pieces move to grapple and impose a preload force across the grapple interface. A battery backup is a redundant power source for each electromagnet in each individual control circuit and is automatically connected upon failure of the primary source. A centerline mounted camera and video monitor are used in cooperation with a target pattern on the reflective surface of the strike plate to effect targeting and alignment.

Monford, Leo G., Jr. (inventor)

1992-01-01

188

Extremely low frequency electromagnetic field exposure causes cognitive impairment associated with alteration of the glutamate level, MAPK pathway activation and decreased CREB phosphorylation in mice hippocampus: reversal by procyanidins extracted from the lotus seedpod.  

PubMed

Lotus seedpod procyanidins (LSPCs) could effectively prevent learning and memory damage and oxidative damage caused by extremely low frequency electromagnetic field (ELF-EMF) exposure. However, LSPCs protect neurons from ELF-EMF-induced damage by mechanisms currently not clear. An excessive release of glutamate is considered to be one of the molecular mechanisms of neuronal damage in several neurological diseases. In this study we determined whether the ELF-EMF (50 Hz, 8 mT, 28 days) exposure induced alterations of glutamate release in mice hippocampus and explored the possible mechanism, and if LSPC treatment normalized its alterations. The results showed that ELF-EMF exposure induced the increased contents of glutamate, GABA, excessively activated NMDA receptors, increasing the number of NMDA receptor 2B (NR2B) and intracellular Ca(2+) concentration [Ca(2+)]i in hippocampus. In addition, ELF-EMF exposure decreased the ERK1/2 and CREB phosphorylation, which suggested that the Ca(2+) influx induced by the ELF-EMF exposure stimulated activity of the ERK, in turn, influences the expression of downstream proteins in this signaling pathway. Besides, ELF-EMF exposure also increased JNK1/2 phosphorylation through the activated ASK1, which plays a pivotal role in hippocampal neuronal cell death. However, oral administration of LSPCs (especially 60 and 90 mg kg(-1)) markedly improved expressions of p-CREB, p-ERK1/2 and p-JNK1/2, accompanied by decreased levels of glutamate, GABA, [Ca(2+)]i and NR2B. Thus, the results from the present study suggest that p-ERK1/2, p-JNK1/2, [Ca(2+)]i and p-CREB expression normalized, possibly via a NMDA receptor-channel through the changes of GABA, glutamate and NR2B, which might be responsible for the neuroprotective or memory enhancing effects of LSPCs. PMID:25066354

Duan, Yuqing; Wang, Zhigao; Zhang, Haihui; He, Yuanqing; Fan, Rong; Cheng, Yanxiang; Sun, Guibo; Sun, Xiaobo

2014-09-01

189

DEGREE SPECTRA OF STRUCTURES JOINT SPECTRA OF STRUCTURES  

E-print Network

DEGREE SPECTRA OF STRUCTURES JOINT SPECTRA OF STRUCTURES MINIMAL PAIRS QUASI-MINIMAL DEGREE Minimal for Joint Spectra #12;DEGREE SPECTRA OF STRUCTURES JOINT SPECTRA OF STRUCTURES MINIMAL PAIRS QUASI-MINIMAL DEGREE DEGREE SPECTRA OF STRUCTURES Degree Spectra of Structures Let A = (N; R1, . . . , Rk

Soskova, Alexandra A.

190

DEGREE SPECTRA OF STRUCTURES JOINT SPECTRA OF STRUCTURES  

E-print Network

DEGREE SPECTRA OF STRUCTURES JOINT SPECTRA OF STRUCTURES PROPERTIES OF JOINT SPECTRA Properties of the Joint Spectra of Sequence of Structures Alexandra A. Soskova Department of Mathematics and Computer of Structures #12;DEGREE SPECTRA OF STRUCTURES JOINT SPECTRA OF STRUCTURES PROPERTIES OF JOINT SPECTRA

Soskova, Alexandra A.

191

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.

192

MATHEMA: A Constructivist Enviroment for Electromagnetism Learning  

Microsoft Academic Search

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

Alexandros Papadimitriou; Georgios Gyftodimos; Maria Grigoriadou

2009-01-01

193

Abstract--With the growing concerns about electromagnetic compatibility of integrated circuits, the need for accurate  

E-print Network

Abstract--With the growing concerns about electromagnetic compatibility of integrated circuits-chip noise sensor dedicated to the study of various aspects of electromagnetic compatibility at circuit level be extended towards online diagnosis and self-healing. Index Terms-- Electromagnetic compatibility, signal

Boyer, Edmond

194

Sensing network for electromagnetic fields generated by seismic activities  

NASA Astrophysics Data System (ADS)

The sensors network is becoming prolific and play now increasingly more important role in acquiring and processing information. Cyber-Physical Systems are focusing on investigation of integrated systems that includes sensing, networking, and computations. The physics of the seismic measurement and electromagnetic field measurement requires special consideration how to design electromagnetic field measurement networks for both research and detection earthquakes and explosions along with the seismic measurement networks. In addition, the electromagnetic sensor network itself could be designed and deployed, as a research tool with great deal of flexibility, the placement of the measuring nodes must be design based on systematic analysis of the seismic-electromagnetic interaction. In this article, we review the observations of the co-seismic electromagnetic field generated by earthquakes and man-made sources such as vibrations and explosions. The theoretical investigation allows the distribution of sensor nodes to be optimized and could be used to support existing geological networks. The placement of sensor nodes have to be determined based on physics of electromagnetic field distribution above the ground level. The results of theoretical investigations of seismo-electromagnetic phenomena are considered in Section I. First, we compare the relative contribution of various types of mechano-electromagnetic mechanisms and then analyze in detail the calculation of electromagnetic fields generated by piezomagnetic and electrokinetic effects.

Gershenzon, Naum I.; Bambakidis, Gust; Ternovskiy, Igor V.

2014-06-01

195

Metamaterial electromagnetic wave absorbers.  

PubMed

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

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

2012-06-19

196

Electromagnetic ferrofluid-based energy harvester  

NASA Astrophysics Data System (ADS)

This Letter investigates the use of ferrofluids for vibratory energy harvesting. In particular, an electromagnetic micro-power generator which utilizes the sloshing of a ferrofluid column in a seismically-excited tank is proposed to transform mechanical motions directly into electricity. Unlike traditional electromagnetic generators that implement a solid magnet, ferrofluids can easily conform to different shapes and respond to very small acceleration levels offering an untapped opportunity to design scalable energy harvesters. The feasibility of the proposed concept is demonstrated and its efficacy is discussed through several experimental studies.

Bibo, A.; Masana, R.; King, A.; Li, G.; Daqaq, M. F.

2012-06-01

197

Electromagnetically induced transparency for x-rays.  

SciTech Connect

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

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

2007-06-22

198

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

199

Introducing electromagnetic field momentum  

NASA Astrophysics Data System (ADS)

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

Yu-Kuang Hu, Ben

2012-07-01

200

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

201

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

202

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

203

Photovoltaic effects on Franz-Keldysh oscillations in photoreflectance spectra: Application to determination of surface Fermi level and surface recombination velocity in undoped GaAs /n-type GaAs epitaxial layer structures  

NASA Astrophysics Data System (ADS)

We demonstrate that the surface Fermi level and surface recombination velocity in undoped GaAs /n-type GaAs (i-GaAs/n-GaAs) epitaxial layer structures can be simultaneously estimated from Franz-Keldysh oscillations (FKOs) in photoreflectance spectra, taking account of the photovoltaic effects. Initially, we performed computational studies on the surface electric fields in i-GaAs /n-GaAs structures under the illumination of a probe beam. The surface electric-field strength is sensitive to the surface Fermi level and surface recombination velocity. We have found that these parameters can be evaluated from the dependence of the surface electric-field strength on the probe-beam power density. Next, we estimated experimentally the surface Fermi level and surface recombination velocity in an as-grown i-GaAs /n-GaAs structure by analyzing the photovoltaic effect on the FKOs. The period of the FKOs increases with a decrease in the probe-beam power density. The surface Fermi level and surface recombination velocity are estimated from the probe-beam power dependence of the surface electric-field strength that is obtained from the analysis of the FKOs. We have also applied the analysis of the photovoltaic effect to the assessment of the GaAs surfaces exposed to the nitridation and the catalytic chemical vapor deposition of SiNx. In addition, we have derived a line-shape function of the FKOs from i-GaAs /n-GaAs structures, which is applicable even to the FKOs influenced by a probe-beam interference phenomenon in a layered structure.

Takeuchi, Hideo; Kamo, Yoshitaka; Yamamoto, Yoshitsugu; Oku, Tomoki; Totsuka, Masahiro; Nakayama, Masaaki

2005-03-01

204

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

205

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.

206

Infrared and Raman spectra of lunar samples from Apollo 11, 12 and 14  

Microsoft Academic Search

We report the room temperature infrared reflectance spectra of several lunar surface rocks in the form of polished slices or butt ends. The spectra were obtained over the frequency range 20-2000 cm-1 throughout the mid and far infrared (5-500µ) region of the electromagnetic spectrum where the fundamental internal and lattice vibrational modes of all minerals and rocks occur.

Clive H. Perry; D. K. Agrawal; E. Anastassakis; R. P. Lowndes; A. Rastogi; N. E. Tornberg

1972-01-01

207

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

208

EMG #121471 Electromagnetics, 25:679693, 2005  

E-print Network

. Keywords electromagnetic compatibility, electromagnetic interference, aperture, cou- pling, finite compatibility (EMC) and electromagnetic interference (EMI) requirements, it is crucial to quantifyEMG #121471 Electromagnetics, 25:679­693, 2005 Copyright © 2005 Taylor & Francis Inc. ISSN: 0272

Ramahi, Omar

209

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

210

Electromagnetic propulsion for spacecraft  

Microsoft Academic Search

Three electromagnetic propulsion technologies, solid propellant pulsed plasma thrusters (PPT), magnetoplasmadynamic (MPD) thrusters, and pulsed inductive thrusters (PIT), were developed for application to auxiliary and primary spacecraft propulsion. Both the PPT and MPD thrusters were flown in space, though only PPT's were used on operational satellites. The performance of operational PPT's is quite poor, providing only approximately 8 percent efficiency

Roger M. Myers

1993-01-01

211

Electromagnetic conic sections  

Microsoft Academic Search

Certain orthogonal coordinate systems naturally correspond to basis vectors which are both curl-free and divergence-free, and hence solve Maxwell's equations. After first comparing several different traditional approaches to computing div, grad, and curl in curvilinear coordinates, we present a new approach, based on these ``electromagnetic'' basis vectors, which combines geometry and physics. Not only is our approach tied to a

Tevian Dray; Corinne A. Manogue

2002-01-01

212

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

213

Physics 2000: Electromagnetic Waves  

NSDL National Science Digital Library

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

Goldman, Martin

2004-07-14

214

Computation of Electromagnetic Fields  

Microsoft Academic Search

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

A. Wexler

1969-01-01

215

What are Electromagnetic Metamaterials?  

NSDL National Science Digital Library

Metamaterials are artificial structures that display properties beyond those available in naturally occuring materials. Materials interact with light and other electromagnetic fields. Because of this, materials can be used to control light in various ways, forming the basis for optical devices. This website from Duke University gives more details and graphs.

2011-08-29

216

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

217

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

218

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

219

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

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

The electromagnetic chemical propulsion concept  

Microsoft Academic Search

A new concept of propulsion to high velocities is presented. It combines the strong points of electrothermal chemical and electromagnetic methods. The projectile is accelerated by electromagnetic forces. Similar to other methods of electromagnetic propulsion, this overcomes the common limitations of conventional and electrothermal guns, caused by limited expansion speed of hot gases at acceptable temperatures. As with electrothermal chemical

Yuri A. Dreizin

1995-01-01

222

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

223

Analytical model for electromagnetic cascades in rotating electric field  

E-print Network

Electromagnetic cascades attract a lot of attention as an important QED effect that will reveal itself in various electromagnetic field configurations at ultrahigh intensities. We study cascade dynamics in rotating electric field analytically and numerically. The kinetic equations for the electron-positron plasma and gamma-quanta are formulated. The scaling laws are derived and analyzed. For the cascades arising far above the threshold the dependence of the cascade parameters on the field frequency is derived. The spectra of high-energy cascade particles are calculated. The analytical results are verified by numerical simulations.

E. N. Nerush; V. F. Bashmakov; I. Yu. Kostyukov

2011-05-19

224

Analytical model for electromagnetic cascades in rotating electric field  

SciTech Connect

Electromagnetic cascades attract a lot of attention as an important quantum electrodynamics effect that will reveal itself in various electromagnetic field configurations at ultrahigh intensities. We study cascade dynamics in rotating electric field analytically and numerically. The kinetic equations for the electron-positron plasma and gamma-quanta are formulated. The scaling laws are derived and analyzed. For the cascades arising far above the threshold the dependence of the cascade parameters on the field frequency is derived. The spectra of high-energy cascade particles are calculated. The analytical results are verified by numerical simulations.

Nerush, E. N.; Bashmakov, V. F.; Kostyukov, I. Yu. [Institute of Applied Physics, Russian Academy of Sciences, 603950 Nizhny Novgorod (Russian Federation)

2011-08-15

225

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

226

DEGREE SPECTRA OF STRUCTURES RELATIVE SPECTRA OF STRUCTURES  

E-print Network

DEGREE SPECTRA OF STRUCTURES RELATIVE SPECTRA OF STRUCTURES PROPERTIES OF RELATIVE SPECTRA Degree Spectra of Structures Alexandra A. Soskova Faculty of Mathematics and Computer Science Sofia University Leeds Logic Seminar Alexandra A. Soskova Degree Spectra of Structures #12;DEGREE SPECTRA OF STRUCTURES

Soskova, Alexandra A.

227

Spectra of stable sonoluminescence  

NASA Astrophysics Data System (ADS)

The continuous emission of picosecond pulses of light has been observed to originate from a bubble trapped at the pressure antinode of a resonant sound field in water and in water/glycerin mixtures. The spectra of this light in several solutions has been measured with a scanning monochrometer/photomultiplier detector system. The spectra are broadband and show strong emission in the UV region. A comparison of this measurement to two other independently produced spectra is made. The spectra are also modeled by a blackbody radiation distribution to determine an effective blackbody temperature and a size is deduced as if Sonoluminescence were characterized by blackbody radiation.

Lewis, Stephen D.

1992-12-01

228

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

229

Calculating core-level excitations and X-ray absorption spectra of medium-sized closed-shell molecules with the algebraic-diagrammatic construction scheme for the polarization propagator.  

PubMed

Core-level excitations are generated by absorption of high-energy radiation such as X-rays. To describe these energetically high-lying excited states theoretically, we have implemented a variant of the algebraic-diagrammatic construction scheme of second-order ADC(2) by applying the core-valence separation (CVS) approximation to the ADC(2) working equations. Besides excitation energies, the CVS-ADC(2) method also provides access to properties of core-excited states, thereby allowing for the calculation of X-ray absorption spectra. To demonstrate the potential of our implementation of CVS-ADC(2), we have chosen medium-sized molecules as examples that have either biological importance or find application in organic electronics. The calculated results of CVS-ADC(2) are compared with standard TD-DFT/B3LYP values and experimental data. In particular, the extended variant, CVS-ADC(2)-x, provides the most accurate results, and the agreement between the calculated values and experiment is remarkable. PMID:25130619

Wenzel, Jan; Wormit, Michael; Dreuw, Andreas

2014-10-01

230

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

2008-05-13

231

Libraries of Stellar Spectra  

NSDL National Science Digital Library

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

2005-04-25

232

Electromagnetic Polarizabilities of Mesons  

E-print Network

The Chiral Perturbation Theory (CHPT) has been very successful in describing low-energy hadronic properties in the non-perturbative regime of Quantum Chromodynamics. The results of ChPT, many of which are currently under active experimental investigation, provide stringent predictions of many fundamental properties of hadrons, including quantities such as electromagnetic polarizabilities. Yet, even for the simplest hadronic system, a pion, we still have a broad spectrum of polarizability measurements (MARK II, VENUS, ALEPH, TPC/2g, CELLO, Belle, Crystal Ball). The meson polarizability can be accessed through Compton scattering, so we can measure it through Primakoff reaction. This paper will provide an analysis of the CHPT predictions of the SU(3) meson electromagnetic polarizabilities and outline their relationship to the Primakoff cross section at the kinematics relevant to the planned JLab experiments.

Aleksejevs, A

2014-01-01

233

Electromagnetic Polarizabilities of Mesons  

E-print Network

The Chiral Perturbation Theory (CHPT) has been very successful in describing low-energy hadronic properties in the non-perturbative regime of Quantum Chromodynamics. The results of ChPT, many of which are currently under active experimental investigation, provide stringent predictions of many fundamental properties of hadrons, including quantities such as electromagnetic polarizabilities. Yet, even for the simplest hadronic system, a pion, we still have a broad spectrum of polarizability measurements (MARK II, VENUS, ALEPH, TPC/2g, CELLO, Belle, Crystal Ball). The meson polarizability can be accessed through Compton scattering, so we can measure it through Primakoff reaction. This paper will provide an analysis of the CHPT predictions of the SU(3) meson electromagnetic polarizabilities and outline their relationship to the Primakoff cross section at the kinematics relevant to the planned JLab experiments.

A. Aleksejevs; S. Barkanova

2014-10-25

234

Electromagnetic wave energy converter  

NASA Technical Reports Server (NTRS)

Electromagnetic wave energy is converted into electric power with an array of mutually insulated electromagnetic wave absorber elements each responsive to an electric field component of the wave as it impinges thereon. Each element includes a portion tapered in the direction of wave propagation to provide a relatively wideband response spectrum. Each element includes an output for deriving a voltage replica of the electric field variations intercepted by it. Adjacent elements are positioned relative to each other so that an electric field subsists between adjacent elements in response to the impinging wave. The electric field results in a voltage difference between adjacent elements that is fed to a rectifier to derive dc output power.

Bailey, R. L. (inventor)

1973-01-01

235

Nonlinear gravito-electromagnetism  

NASA Astrophysics Data System (ADS)

There is a non-linear and covariant electromagnetic analogy for gravity, in which the full Bianchi identities are Maxwell-type equations for the free gravitational field, encoded in the Weyl tensor. This tensor gravito-electromagnetism is based on a covariant generalization of spatial vector algebra and calculus to spatial tensor fields, and includes all non-linear effects from the gravitational field and matter sources. The non-linear vacuum Bianchi equations are invariant under spatial duality rotation of the gravito-electric and gravito-magnetic tensor fields. The super-energy density and super-Poynting vector of the gravitational field are natural duality invariants, and satisfy a super-energy conservation equation.

Maartens, Roy

2008-06-01

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

Ab initio calculations on SnCl2 and Franck-Condon factor simulations of its ã-X and B-X absorption and single-vibronic-level emission spectra.  

PubMed

Minimum-energy geometries, harmonic vibrational frequencies, and relative electronic energies of some low-lying singlet and triplet electronic states of stannous dichloride, SnCl(2), have been computed employing the complete-active-space self-consistent-field/multireference configuration interaction (CASSCF/MRCI) and/or restricted-spin coupled-cluster single-double plus perturbative triple excitations [RCCSD(T)] methods. The small core relativistic effective core potential, ECP28MDF, was used for Sn in these calculations, together with valence basis sets of up to augmented correlation-consistent polarized-valence quintuple-zeta (aug-cc-pV5Z) quality. Effects of outer core electron correlation on computed geometrical parameters have been investigated, and contributions of off-diagonal spin-orbit interaction to relative electronic energies have been calculated. In addition, RCCSD(T) or CASSCF/MRCI potential energy functions of the X(1)A(1), ã(3)B(1), and B(1)B(1) states of SnCl(2) have been computed and used to calculate anharmonic vibrational wave functions of these three electronic states. Franck-Condon factors between the X (1)A(1) state, and the ã (3)B(1) and B (1)B(1) states of SnCl(2), which include anharmonicity and Duschinsky rotation, were then computed, and used to simulate the ã-X and B-X absorption and corresponding single-vibronic-level emission spectra of SnCl(2) which are yet to be recorded. It is anticipated that these simulated spectra will assist spectroscopic identification of gaseous SnCl(2) in the laboratory and/or will be valuable in in situ monitoring of SnCl(2) in the chemical vapor deposition of SnO(2) thin films in the semiconductor gas sensor industry by laser induced fluorescence and/or ultraviolet absorption spectroscopy, when a chloride-containing tin compound, such as tin dichloride or dimethyldichlorotin, is used as the tin precursor. PMID:17640129

Lee, Edmond P F; Dyke, John M; Mok, Daniel K W; Chow, Wan-ki; Chau, Foo-tim

2007-07-14

238

Electromagnetic propulsion of satellites  

Microsoft Academic Search

A propulsion system using the electromagnetic repulsion between two parallel conductors, carrying in opposite directions high currents, is considered. Very high projection velocities, above 70000m\\/s, are expected, corresponding with a thrust reaching 200000N. Such propulsion system can operate in pulsed conditions, throwing 10-6kg aluminium wires at a frequency of 10Hz. Then the average value of the thrust is 0.7N; so

Alexandre Pozwolski

2008-01-01

239

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

240

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

241

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

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)

1996-01-01

243

Ordinary electromagnetic mode instability  

NASA Technical Reports Server (NTRS)

The instability of the ordinary electromagnetic mode propagating perpendicular to an external magnetic field is studied for a single-species plasma with ring velocity distribution. The marginal instability boundaries for both the purely growing mode and the propagating growing modes are calculated from the instability criteria. The dispersion characteristics for various sets of plasma parameters are also given. The typical growth rates are of the order of the cyclotron frequency.

Cheng, C. Z.

1974-01-01

244

Electromagnetic polarizabilities of hadrons  

SciTech Connect

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

Friar, J.L.

1988-01-01

245

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

246

A Magic Electromagnetic Field  

E-print Network

An electromagnetic field of simple algebraic structure is simply derived. It turns out to be the G=0 limit of the charged rotating Kerr-Newman metrics. These all have gyromagnetic ratio 2, the same as the Dirac electron. The charge and current distributions giving this high gyromagnetic ratio have charges of both signs rotating at close to the velocity of light. It is conjectured that something similar may occur in the quantum electrodynamic charge distribution surrounding the point electron.

Donald Lynden-Bell

2002-07-02

247

Hyperphysics: Electromagnetic Waves  

NSDL National Science Digital Library

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

Nave, Carl R.

2012-03-25

248

Method of electromagnetic exploration  

SciTech Connect

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

Nekut, A.G. Jr.

1987-05-05

249

The KLOE electromagnetic calorimeter  

NASA Astrophysics Data System (ADS)

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.

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

2002-11-01

250

Flash memory electromagnetic compatibility  

Microsoft Academic Search

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

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

2006-01-01

251

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

252

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

253

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

254

Electromagnetic braking for Mars spacecraft  

NASA Technical Reports Server (NTRS)

Aerobraking concepts are being studied to improve performance and cost effectiveness of propulsion systems for Mars landers and Mars interplanetary spacecraft. Access to megawatt power levels (nuclear power coupled to high-storage inductive or capacitive devices) on a manned Mars interplanetary spacecraft may make feasible electromagnetic braking and lift modulation techniques which were previously impractical. Using pulsed microwave and magnetic field technology, potential plasmadynamic braking and hydromagnetic lift modulation techniques have been identified. Entry corridor modulation to reduce loads and heating, to reduce vertical descent rates, and to expand horizontal and lateral landing ranges are possible benefits. In-depth studies are needed to identify specific design concepts for feasibility assessments. Standing wave/plasma sheath interaction techniques appear to be promising. The techniques may require some tailoring of spacecraft external structures and materials. In addition, rapid response guidance and control systems may require the use of structurally embedded sensors coupled to expert systems or to artificial intelligence systems.

Holt, A. C.

1986-01-01

255

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

256

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

257

Ejs Electromagnetic Wave Model  

NSDL National Science Digital Library

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

Aguirregabiria, Juan

2008-08-20

258

Integrated Circuit Electromagnetic Immunity Handbook  

NASA Astrophysics Data System (ADS)

This handbook presents the results of the Boeing Company effort for NASA under contract NAS8-98217. Immunity level data for certain integrated circuit parts are discussed herein, along with analytical techniques for applying the data to electronics systems. This handbook is built heavily on the one produced in the seventies by McDonnell Douglas Astronautics Company (MDAC, MDC Report E1929 of 1 August 1978, entitled Integrated Circuit Electromagnetic Susceptibility Handbook, known commonly as the ICES Handbook, which has served countless systems designers for over 20 years). Sections 2 and 3 supplement the device susceptibility data presented in section 4 by presenting information on related material required to use the IC susceptibility information. Section 2 concerns itself with electromagnetic susceptibility analysis and serves as a guide in using the information contained in the rest of the handbook. A suggested system hardening requirements is presented in this chapter. Section 3 briefly discusses coupling and shielding considerations. For conservatism and simplicity, a worst case approach is advocated to determine the maximum amount of RF power picked up from a given field. This handbook expands the scope of the immunity data in this Handbook is to of 10 MHz to 10 GHz. However, the analytical techniques provided are applicable to much higher frequencies as well. It is expected however, that the upper frequency limit of concern is near 10 GHz. This is due to two factors; the pickup of microwave energy on system cables and wiring falls off as the square of the wavelength, and component response falls off at a rapid rate due to the effects of parasitic shunt paths for the RF energy. It should be noted also that the pickup on wires and cables does not approach infinity as the frequency decreases (as would be expected by extrapolating the square law dependence of the high frequency roll-off to lower frequencies) but levels off due to mismatch effects.

Sketoe, J. G.

2000-08-01

259

Action spectra again?  

PubMed

Action spectroscopy has a long history and is of central importance to photobiological studies. Action spectra were among the first assays to point to chlorophyll as the molecule most responsible for plant growth and to DNA as the genetic material. It is useful to construct action spectra early in the investigation of new areas of photobiological research in an attempt to determine the wavelength limits of the radiation region causing the studied response. But due to the severe absorption of ultraviolet (UV) radiation by biological samples, UV action spectra were first limited to small cells (bacteria and fungi). Advances in techniques (e.g. single cell culture) and analysis allowed accurate action spectra to be reported even for mammalian cells. But precise analytical action spectra are often difficult to obtain when large, pigmented, or groups of cells are investigated. Here some action spectra are limited in interpretation and merely supply a wavelength vs effect curve. When polychromatic sources are employed, the interpretation of action spectra is even more complex and formidable. But such polychromatic action spectra can be more directly related to ambient responses. Since precise action spectra usually require the completion of a relatively large number of careful experiments using somewhat sophisticated equipment over a range of at least six wavelengths, they are often not pursued. But they remain central to the elucidation of the effect being studied. The worldwide community has agreed that stratospheric ozone is depleting, with the possibility of a consequent rise in the amount of UV-B (290-320 nm) reaching the earth's surface. It is therefore essential that new action spectra be completed for UV-B effects on a large variety of responses of human, animal, and aquatic plant systems. Combining these action spectra with the known amounts of UV-B reaching the biosphere can give rise to solar UV effectiveness spectra that, in turn, can give rise to estimates of effect. Preliminary estimates suggest that ozone layer depletion may seriously impact such important biological end-points as skin cancer, cataracts, the immune system, crop yields, and oceanic phytoplankton. So action spectra continue to play a central role in important photobiological research. PMID:1798760

Coohill, T P

1991-11-01

260

Electromagnetic Radiations Emanating From A Quenched Superconducting Electromagnet  

Microsoft Academic Search

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

S. A. Marshall; D. G. Yerg

1990-01-01

261

Theory of electromagnetic fluctuations for magnetized multi-species plasmas  

NASA Astrophysics Data System (ADS)

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.; Araneda, Jaime; Muñoz, Víctor; Moya, Pablo S.; F.-Viñas, Adolfo; Valdivia, Juan A.

2014-09-01

262

Observations of ELF electromagnetic waves associated with equatorial spread F  

NASA Technical Reports Server (NTRS)

Extreme low frequency electromagnetic waves have been observed below the F peak in the equatorial ionosphere by instruments onboard OGO-6. Electrostatic wave observations indicate that the steep gradient was unstable to the process which causes equatorial spread F above the region where the electromagnetic waves were observed. The data are very similar to observations near the polar cusp and give further evidence that ELF waves are excluded from regions of rapid and irregular density increases. Low level electromagnetic waves with similar properties were occasionally observed on the nightside by the OVI-17 electric field sensor and may be plasmaspheric hiss which has propagated to low altitude.

Kelley, M. C.; Holtet, J. A.; Tsurutani, B. T.

1979-01-01

263

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

2014-06-05

264

Electromagnetic fields in bone repair and adaptation  

NASA Astrophysics Data System (ADS)

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

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

1995-01-01

265

Source spectra of seismic hum  

NASA Astrophysics Data System (ADS)

The observation of seismic hum from 2 to 20 mHz, also known as Earth's background free oscillations, has been established. Recent observations by broad-band seismometers show simultaneous excitation of Love waves (fundamental toroidal modes) and Rayleigh waves (fundamental spheroidal modes). The excitation amplitudes above 10 mHz can be explained by random shear traction sources on Earth's surface. With estimated source distributions, the most likely excitation mechanism is a linear coupling between ocean infragravity waves and seismic surface waves through seafloor topography. Observed Love and Rayleigh wave amplitudes below 5 mHz suggest that surface pressure sources could also contribute to their excitations, although the amplitudes have large uncertainties due to the high noise levels of the horizontal components. To quantify the observation, we develop a new method for estimation of the source spectra of random tractions on Earth's surface by modelling cross-spectra between pairs of stations. The method is to calculate synthetic cross-spectra for spatially isotropic and homogeneous excitations by random shear traction and pressure sources, and invert them with the observed cross-spectra to obtain the source spectra. We applied this method to the IRIS, ORFEUS, and F-net records from 618 stations with three components of broad-band seismometers for 2004-2011. The results show the dominance of shear traction above 5 mHz, which is consistent with past studies. Below 5 mHz, however, the spectral amplitudes of the pressure sources are comparable to those of shear traction. Observed acoustic resonance between the atmosphere and the solid Earth at 3.7 and 4.4 mHz suggests that atmospheric disturbances are responsible for the surface pressure sources, although non-linear ocean wave processes are also candidates for the pressure sources. Excitation mechanisms of seismic hum should be considered as a superposition of the processes of the solid Earth, atmosphere and ocean as a coupled system.

Nishida, Kiwamu

2014-10-01

266

Psychological studies in nonionizing electromagnetic energy research.  

PubMed

Research on nonionizing electromagnetic (NIEM) energy has focused on potential hazards, and to a lesser degree beneficial applications, of radiofrequency (RF) fields and extremely low frequency (ELF) fields. The history of research on the potential biological effects of NIEM contains many psychological investigations. These psychological investigations were conducted primarily in the discipline of biopsychology and included interdisciplinary cooperation with engineering, physical sciences, and other disciplines not routinely associated with psychology. The current recommended exposure level for RF is based on behavioral observations of laboratory animals. Psychology has been and continues to be in the midst of controversy regarding the ability of low-frequency, low-level electromagnetic energy or electric and magnetic fields to affect living organisms. PMID:8340784

O'Connor, M E

1993-01-01

267

Comparison of electromagnetic compatibility of different PV inverter  

Microsoft Academic Search

This is a tutorial paper that studies the electromagnetic compatibility (EMC) of single-phase grid connected PV inverters by investigating the impact of switching frequency, the stray impedance and the inverter topology on the EMC. The study is based on the time-domain simulation of practical circuit model using the PSIM software package and the frequency-domain spectra analysis in the MabLab environment.

Qin Jiang; James Brown

2001-01-01

268

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

269

Avoiding electromagnetic artifacts when recording auditory steady-state responses.  

PubMed

Electromagnetic artifacts can occur when recording multiple auditory steady-state responses evoked by sinusoidally amplitude modulated (SAM) stimuli. High-intensity air-conducted stimuli evoked responses even when hearing was prevented by masking. Additionally, high-intensity bone-conducted stimuli evoked responses that were completely different from those evoked by air-conducted stimuli of similar sensory level. These artifacts were caused by aliasing since they did not occur when recordings used high analog-digital (AD) conversion rates or when high frequencies in the electroencephalographic (EEG) signal were attenuated by steep-slope low-pass filtering. Two possible techniques can displace aliased energy away from the response frequencies: (1) using an AD rate that is not an integer submultiple of the carrier frequencies and (2) using stimuli with frequency spectra that do not alias back to the response frequencies, such as beats or "alternating SAM" tones. Alternating SAM tones evoke responses similar to conventional SAM tones, whereas beats produce significantly smaller responses. PMID:15553654

Picton, Terence W; John, M Sasha

2004-09-01

270

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

271

Cognitive Effects of Electromagnetic Fields in Humans  

Microsoft Academic Search

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

Alan W. Preece

272

Electromagnetic Meissner-Effect Launcher  

NASA Technical Reports Server (NTRS)

Proposed electromagnetic Meissner-effect launching apparatus differs from previous electromagnetic launchers; no need for electromagnet coil on projectile. Result, no need for brush contacts and high-voltage commutation equipment to supply current directly to projectile coil, or for pulse circuitry to induce current in projectile coil if brush contacts not used. Compresses magnetic field surrounding rear surface of projectile, creating gradient of magnetic pressure pushing projectile forward.

Robertson, Glen A.

1990-01-01

273

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

274

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

E-print Network

-Network Electromagnetic Compatibility and Safety Vladimir Mordachev Belorussian State University of Informatics and Radioelectronics (BSUIR) Electromagnetic Compatibility Laboratory 6, P.Brovki st., Minsk 220013, Belarus E of electromagnetic environment in wireless networks affecting its intra- network electromagnetic compatibility

Loyka, Sergey

275

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

E-print Network

IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY, VOL. 55, NO. 2, APRIL 2013 395 Electromagnetic to electromagnetic interference (EMI) is becoming a critical aspect of signal integrity analysis. For mod- eling, delay, electromagnetic in- terference (EMI), incident fields, longitudinal partitioning, tran- sient

Roy, Sourajeet

276

THE SPECTRA OF THE DOUBLY AND TRIPLY IONIZED RARE EARTHS  

Microsoft Academic Search

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

G. H. Dieke; H. M. Crosswhite

1963-01-01

277

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

278

Spectra over complex terrain  

SciTech Connect

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

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

1981-01-01

279

Electromagnetically controllable osteoclast activity.  

PubMed

The time-varying electromagnetic field (EMF) has been widely studied as one of the exogenous stimulation methods for improving bone healing. Our previous study showed that osteogenic differentiation of adipose-derived stem cells was accelerated by a 45-Hz EMF, whereas a 7.5-Hz EMF inhibited osteogenic marker expression. Accordingly, we hypothesized that each negative and positive condition for the osteogenic differentiation could inversely influence osteoclast formation and differentiation. Here, we demonstrated that osteoclast formation, differentiation, and activity can be regulated by altering the frequency of the electromagnetic stimulation, such as 7.5 (negative for osteogenic differentiation) and 45 Hz (positive for osteogenic differentiation). A 45 Hz EMF inhibited osteoclast formation whereas a 7.5-Hz EMF induced differentiation and activity. Osteoclastogenic markers, such as NFATc1, TRAP, CTSK, MMP9, and DC-STAMP were highly expressed under the 7.5-Hz EMF, while they were decreased at 45 Hz. We found that the 7.5-Hz EMF directly regulated osteoclast differentiation through ERK and p38 MAPK activation, whereas the EMF at 45 Hz suppressed RANKL-induced phosphorylation of I?B. Additionally, actin ring formation with tubules and bone resorptive activity were enhanced at 7.5 Hz through increased integrin ?3 expression. However, these were inhibited at 45 Hz. Although many questions remain unanswered, our study indicates that osteoclast formation and differentiation were controllable using physical tools, such as an EMF. It will now be of great interest to study the ill-defined correlation between electromagnetic conditions and osteoclast activities, which eventually could lead to determining the therapeutic characteristics of an EMF that will treat bone-related diseases. PMID:24556539

Hong, Jung Min; Kang, Kyung Shin; Yi, Hee-Gyeong; Kim, Shin-Yoon; Cho, Dong-Woo

2014-05-01

280

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

281

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

2013-12-04

282

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

283

Electromagnetic pump stator coil  

SciTech Connect

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

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

1996-01-01

284

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

285

Electromagnetic Processes in ?EFT  

NASA Astrophysics Data System (ADS)

Nuclear electromagnetic currents derived in a chiral-effective-field-theory framework including explicit nucleons, ? isobars, and pions up to N2LO, i.e. ignoring loop corrections, are used in a study of neutron radiative captures on protons and deuterons at thermal energies, and of A=2 and 3 nuclei magnetic moments. With the strengths of the ?-excitation currents determined to reproduce the n-p cross section and isovector combination of the trinucleon magnetic moments, we find that the cross section and photon circular polarization parameter, measured respectively in n-d and /rightarrow n - d processes, are significantly underpredicted by theory.

Pastore, S.; Schiavilla, R.; Goity, J. L.

286

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

287

Electromagnetic Processes in $?$EFT  

E-print Network

Nuclear electromagnetic currents derived in a chiral-effective-field-theory framework including explicit nucleons, $\\Delta$ isobars, and pions up to N$^2$LO, {\\it i.e.} ignoring loop corrections, are used in a study of neutron radiative captures on protons and deuterons at thermal energies, and of $A$=2 and 3 nuclei magnetic moments. With the strengths of the $\\Delta$-excitation currents determined to reproduce the $n$-$p$ cross section and isovector combination of the trinucleon magnetic moments, we find that the cross section and photon circular polarization parameter, measured respectively in $n$-$d$ and $\\vec{n}$-$d$ processes, are significantly underpredicted by theory.

S. Pastore; R. Schiavilla; J. L. Goity

2008-09-15

288

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

289

Probing the quantum-mechanical equivalent-photon spectrum for electromagnetic dissociation of relativistic uranium projectiles  

E-print Network

Electromagnetic fission cross sections for the reactions U + (Be, C, Al, Cu, In, Au, U) at E/A = 0.6 and 1.0 GeV are compared to theoretical calculations using recently proposed quantum-mechanical equivalent-photon spectra. In contrast to semi-classical calculations, systematically lower cross sections are obtained that cannot reproduce the experimental results. Furthermore, we point out that the study of electromagnetic fission cross sections or electromagnetic 1-neutron removal cross sections alone cannot provide unambiguous information on the excitation of the double giant dipole resonance.

Th. Rubehn; W. F. J. Mueller; W. Trautmann

1996-12-06

290

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

291

Electromagnetic Neutrino Properties and Neutrino Oscillations in Electromagnetic Fields  

E-print Network

The presence of medium and external magnetic field change electromagnetic properties of neutrino. In this article the behavior of neutrino magnetic moment in electromagnetic field is considered. On the basis the Bargmann-Michel-Telegdi equation for the case of models with CP invariance and P nonconservation the new type of neutrino resonances $\

A. M. Egorov; A. E. Lobanov; A. I. Studenikin

1999-02-23

292

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 to the Nijmegen data-base [3] characterized by 2 per datum close to one. They should therefore be viewed as phase, including energy spectra, electromagnetic form factors, and capture reactions, is critically reviewed within

Thomas Jefferson National Accelerator Facility

293

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

294

Electromagnetic interaction of metamaterials  

NASA Astrophysics Data System (ADS)

The observation of extraordinary transmission through subwavelength apertures has propelled a great interest in understanding its nature. It defies classical theories of electromagnetic interaction by demanding a closer examination of the surface properties. Traditionally, as surface features become much smaller in size than a single wavelength of interest, the structure is essentially continuous. Any periodic subwavelength corrugation or aperture array should not interact strongly with an incident field and therefore not contribute to any significant transmission through the film. We find that this is not always the case and that we may tune the surface geometry at these scales to affect the overall medium behavior. It is possible that a material may transcend its own natural properties and, in essence, become a metamaterial. The following analysis examines the concepts of metamaterials from a fundamental viewpoint. It does not seek to disrupt classical theories but instead demonstrates their validity to describe a new phenomenon. Several theories have been proposed that offer unique surface interactions as evidence of enhanced transmission. It is proposed that a fundamental Maxwell representation is sufficient in predicting the interaction of an electromagnetic wave with a metamaterial. In particular, a formalism has been developed to analyze enhanced transmission through a metallic grating structure. To experimentally validate this model, a fabrication procedure has been developed that allows for the production of quality thick film structures with subwavelength features. Finally, the analysis of metamaterials looks towards the RF spectrum to demonstrate a novel design to achieve conformal waveguides and antennas.

Canales, Peter R.

295

Interactions between electromagnetic fields  

NASA Astrophysics Data System (ADS)

We applied for this grant to support a workshop at Erice, Italy. This workshop has been commonly called Erice School and the main subject of this workshop is the interaction of electromagnetic fields with biological cells and molecules. The grant from ONR enabled us to invite American scientists to participants in this workshop and deliver scientific papers. The duration of the Erice School was ten days. Therefore, we had sufficient time to discuss the problems of electromagnetic radiations. Vigorous discussions took place during official sessions and during private conversations. The participants of this workshop are mostly those who have been active in the research on bioelectromagnetics, but there are some numbers of speakers who discussed the basic electrical and magnetic properties of polyelectrolytes, biological membranes and tissue. The workshop was unique in that there were participants with a variety of training backgrounds. This enabled us to exchange the information between applied scientists and basic scientists. Also, active exchanges of opinions took place between biological scientists and physical scientists.

Schwan, H. P.

1985-02-01

296

Structural composites with integrated electromagnetic functionality  

E-print Network

Structural composites with integrated electromagnetic functionality Syrus C. Nemat-Nasser, Alireza structural functionality. This integration of both electromagnetic and structural functionality throughout. INTRODUCTION Our work on multifunctional structural composites targets the integration of electromagnetic

Nemat-Nasser, Sia

297

Localization of Classical Waves II: Electromagnetic Waves.  

E-print Network

Localization of Classical Waves II: Electromagnetic Waves. Alexander Figotin \\Lambda Department We consider electromagnetic waves in a medium described by a position dependent dielectric constant at all times. Localization of electromagnetic waves is a consequence of Anderson localization

298

Transmitting Electromagnetic Energy into Liquids  

NASA Technical Reports Server (NTRS)

Rough liquid surface enhances coupling. Agitating surface of liquid nitrogen bath with periodic or aperiodic excitation enhances electromagnetic coupling between microwave horn and blackbody temperature standard immersed in liquid. Useful in interfaces between electromagnetic radiation and liquids. Biomedical, radar, and meteorological applications.

Johnston, E. J.

1984-01-01

299

Electromagnetic Navigation during Flexible Bronchoscopy  

Microsoft Academic Search

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

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

2003-01-01

300

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

301

On quantization of electromagnetic field  

E-print Network

These are six papers joined by the same title. The main topics are: 1. algebraic nature of quantization of relativistic fields, 2. constructive definition of space of states of quantum electromagnetic field, 3. structure of space of states of quantum electromagnetic field from functional analysis standpoint.

D. A. Arbatsky

2004-02-04

302

NISTHB 150-11 Electromagnetic  

E-print Network

NISTHB 150-11 NVLAP Electromagnetic Compatibility and Telecommunications Bethany Hackett Bradley Moore Dennis Camell http://dx.doi.org/10.6028/NIST.HB.150-11 #12;NISTHB 150-11 NVLAP Electromagnetic Compatibility and Telecommunications Bethany Hackett Bradley Moore National Voluntary Laboratory Accreditation

Perkins, Richard A.

303

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

304

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

305

On the dynamical spectra of S-bursts in the Jovian radio emission. II. Observations and analysis  

Microsoft Academic Search

Available observational data on the dynamical spectra of S-bursts in Jupiter's radio emission are analyzed and classified on the basis of the theoretical model put forward in Part I of this study. The observed dynamical spectra can be explained by the effect of surface perturbations in the Io-Jupiter flux tube on the transformation of plasma waves to the electromagnetic waves.

A. G. Boev; M. Yu. Luk'yanov; N. A. Tsvyk

1993-01-01

306

ECSS Space Systems Electromagnetic Compatibility Handbook  

NASA Astrophysics Data System (ADS)

This paper provides an overview of the final draft of the ECSS EMC Handbook (European Cooperation for Space Standardization, Space Systems Electromagnetic Compatibility Handbook), ECSS-E-HB-20-07A [1] that has been written by a working group involving representatives of European space industry, CNES (Centre National d'Études Spatiales) and ESA (European Space Agency). The purpose of the Handbook is to provide practical and helpful information for Electromagnetic Compatibility in the development of spacecraft equipment and systems. It gathers experience, know-how and lessons-learnt from the European space community with the aim to assist engineers throughout the design and development phases. The Handbook discusses system level activities and suggests design techniques, analyses and test methods. It also complements the ECSS-E-ST-20-07C standard (Space engineering - Electromagnetic compatibility) [2] by providing rationale for unit level test requirements. The ultimate objective of the Handbook is to guide engineers towards solid spacecraft EMC design and to assist them in the decision making process to avoid lengthy negotiations or late adjustments.

Trougnou, L.

2012-05-01

307

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

308

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.

Bacca, Sonia

2014-01-01

309

Electromagnetically Induced Transparency for X Rays  

SciTech Connect

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

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

2007-06-22

310

Electromagnetically induced transparency for x rays.  

PubMed

Electromagnetically induced transparency is predicted for x rays in laser-dressed neon gas. The x-ray photoabsorption cross section and polarizability near the Ne K edge are calculated using an ab initio theory suitable for optical strong-field problems. The laser wavelength is tuned close to the transition between 1s(-1)3s and 1s(-1)3p approximately 800 nm). The minimum laser intensity required to observe electromagnetically induced transparency is of the order of 10(12) W/cm(2). The ab initio results are discussed in terms of an exactly solvable three-level model. This work opens new opportunities for research with ultrafast x-ray sources. PMID:17678019

Buth, Christian; Santra, Robin; Young, Linda

2007-06-22

311

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

312

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

PubMed

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

Preston, Thomas C; Signorell, Ruth

2012-09-18

313

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

314

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

315

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

316

The Electromagnetic Spectrum  

NSDL National Science Digital Library

In this lesson, students are introduced to the electromagnetic spectrum. They observe a demonstration of the visible light spectrum created by a flashlight and a prism, complete an activity sheet where they identify the wavelength that is involved in technologies used in their communities, and learn about satellite sensors that remotely sense data. Student worksheets, a data sheet, answer keys, and Web links are included. This is Lesson 3 in Understanding Light, part of IMAGERS, Interactive Media Adventures for Grade School Education using Remote Sensing. The website provides hands-on activities in the classroom supporting the science content in two interactive media books, The Adventures of Echo the Bat and Amelia the Pigeon.

317

Nanofocusing of electromagnetic radiation  

NASA Astrophysics Data System (ADS)

Nanofocusing of electromagnetic radiation, that is, reducing the cross sections of propagating optical modes far beyond the diffraction limit in dielectric media, can be achieved in tapered metal-dielectric waveguides that support surface plasmon-polariton modes. Although the main principles of nanofocusing were formulated over a decade ago, a deep theoretical understanding and conclusive experimental verification were achieved only a few years ago. These advances have spawned a variety of new important technological possibilities for the efficient delivery, control and manipulation of optical radiation on the nanoscale. Here, we present the underlying physical principles of radiation nanofocusing in metallic nanostructures, overview recent progress and major developments, and consider future directions and potential applications of this subfield of nano-optics.

Gramotnev, Dmitri K.; Bozhevolnyi, Sergey I.

2014-01-01

318

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

319

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

320

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

321

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

322

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

323

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

324

Gravitational mass in electromagnetic field  

E-print Network

A fraction of energy is theoretically predicted to be captured from electromagnetic field to form a gravitating mass, when a low-mass charged particle enters the strong field from a region of no electromagnetism. In this paper the mass variation has been calculated for a charged particle on free-fall in the constraint electromagnetic field. It has been shown that there is an evident effect to the variation in mass when the low-mass charged particle is in the strong field.

Zihua Weng

2008-07-28

325

ELECTROMAGNETIC FIELD EFFECTS IN EXPLOSIVES  

SciTech Connect

Present and previous research on the effects of electromagnetic fields on the initiation and detonation of explosives and the electromagnetic properties of explosives are reviewed. Among the topics related to detonating explosives are: enhancement of performance; and control of initiation and growth of reaction. Two series of experiments were performed to determine the effects of 1-T magnetic fields on explosive initiation and growth in the modified gap test and on the propagation of explosively generated plasma into air. The results have implications for the control of reactions in explosives and for the use of electromagnetic particle velocity gauges.

Tasker, D. G.; Whitley, V. H. [MS J566, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Lee, R. J. [Lndian Head Division, Naval Surface Warfare Center, Indian Head, MD 20640 (United States)

2009-12-28

326

Comparison between electroglottography and electromagnetic glottography.  

PubMed

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

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

2000-01-01

327

Comparison between electroglottography and electromagnetic glottography  

SciTech Connect

Newly developed glottographic sensors, utilizing high-frequency propagating electromagnetic waves, were compared to a well-established electroglottographic device. The comparison was made on four male subjects under different phonation conditions, including three levels of vocal fold adduction (normal, breathy, and pressed), three different registers (falsetto, chest, and fry), and two different pitches. Agreement between the sensors was always found for the glottal closure event, but for the general wave shape the agreement was better for falsetto and breathy voice than for pressed voice and vocal fry. Differences are attributed to the field patterns of the devices. Whereas the electroglottographic device can operate only in a conduction mode, the electromagnetic device can operate in either the forward scattering (diffraction) mode or in the backward scattering (reflection) mode. Results of our tests favor the diffraction mode because a more favorable angle imposed on receiving the scattered (reflected) signal did not improve the signal strength. Several observations are made on the uses of the electromagnetic sensors for operation without skin contact and possibly in an array configuration for improved spatial resolution within the glottis. (c) 2000 Acoustical Society of America.

Titze, Ingo R. [Department of Speech Pathology and Audiology and National Center for Voice and Speech, The University of Iowa and the Denver Center for the Performing Arts, Iowa City, Iowa 52242 (United States)] [Department of Speech Pathology and Audiology and National Center for Voice and Speech, The University of Iowa and the Denver Center for the Performing Arts, Iowa City, Iowa 52242 (United States); Story, Brad H. [Department of Speech Pathology and Audiology and National Center for Voice and Speech, The University of Iowa and the Denver Center for the Performing Arts, Iowa City, Iowa 52242 (United States)] [Department of Speech Pathology and Audiology and National Center for Voice and Speech, The University of Iowa and the Denver Center for the Performing Arts, Iowa City, Iowa 52242 (United States); Burnett, Gregory C. [Department of Applied Science, University of California at Davis, and Lawrence Livermore National Laboratory, Livermore, California 94557 (United States)] [Department of Applied Science, University of California at Davis, and Lawrence Livermore National Laboratory, Livermore, California 94557 (United States); Holzrichter, John F. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)] [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Ng, Lawrence C. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)] [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Lea, Wayne A. [Speech Sciences Institute, Apple Valley, Minnesota 55124 (United States)] [Speech Sciences Institute, Apple Valley, Minnesota 55124 (United States)

2000-01-01

328

Nonlinear evolution of electromagnetic ion cyclotron waves  

SciTech Connect

Hybrid Vlasov-Fourier modeling is used to investigate the nonlinear evolution of electromagnetic ion cyclotron (EMIC) waves driven by proton temperature anisotropy in plasmas with a population of He{sup +} ions and a cold proton background. In the pure proton-electron plasma, most of the free energy is converted into high-amplitude waves and currents. In the nonlinear stage, within a few hundred proton gyroperiods after the saturation, the wave spectrum shifts toward lower wave numbers and frequencies, from {omega}{approx}0.6{Omega}{sub p} to below {omega}{approx}0.25{Omega}{sub p}. In the presence of even a small population of He{sup +} ions almost all of the free energy is used in He{sup +} heating. The wave activity in the saturated state moves from the linearly unstable upper branch to the linearly stable lower one. In the presence of a background of cold protons, the waves can propagate in the frequency stop-band. Our results demonstrate that linear stability theory cannot be used to estimate the characteristics of the expected saturated wave spectra in the terrestrial magnetosphere. Significantly, our nonlinear simulations produce wave spectra which are in close agreement with the EMIC waves observed in situ by satellites as well as by ground-based magnetometers positioned at the ends of the magnetic field lines.

Silin, I.; Sydora, R. D.; Mann, I. R.; Sauer, K. [Department of Physics, University of Alberta, Edmonton, Alberta T6G 2G7 (Canada); Mace, R. L. [School of Physics, University of KwaZulu-Natal, Durban 4000 (South Africa)

2011-04-15

329

Nonlinear fan instability of electromagnetic waves  

SciTech Connect

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

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

2010-10-15

330

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

331

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

332

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

333

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

334

Kinetic Equation with Electromagnetic Interactions.  

National Technical Information Service (NTIS)

A kinetic equation for a plasma with electromagnetic interactions is derived in the shielding approximation. The equation is the analog of the Landau equation and has the same structure as the Landau equation but with a velocity dependent interaction repl...

J. T. Hogan, M. B. Lewis

1967-01-01

335

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

336

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

337

Electromagnetic recording and playback device  

E-print Network

The purpose of this thesis is the design and manufacture of an electromagnetic recording and playback device. The device was designed to record information onto a steel wire which can replay the signal. The device is of ...

Chavez, Dylan, 1981-

2004-01-01

338

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

339

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

340

Time Reversal of Electromagnetic Waves  

Microsoft Academic Search

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

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

2004-01-01

341

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

342

Distinguishing low frequency oscillations within the 1\\/f spectral behaviour of electromagnetic brain signals  

Microsoft Academic Search

BACKGROUND: It has been acknowledged that the frequency spectrum of measured electromagnetic (EM) brain signals shows a decrease in power with increasing frequency. This spectral behaviour may lead to difficulty in distinguishing event-related peaks from ongoing brain activity in the electro- and magnetoencephalographic (EEG and MEG) signal spectra. This can become an issue especially in the analysis of low frequency

Charmaine Demanuele; Christopher J James; Edmund JS Sonuga-Barke

2007-01-01

343

Gyrofluid Theory and Simulation of Electromagnetic Turbulence and Transport in Tokamak Plasmas  

E-print Network

calculations, and good agreement is found for both the finite- ion temperature gradient (ITG) and kinetic Alfv nonlinear simulations. This work extends ear- lier electrostatic gyrofluid models to include magnetic and temperature fluctua- tion spectra. Direct comparisons of transport fluxes reveal that electromagnetic effects

Hammett, Greg

344

Interaction of intense electromagnetic fields with SF\\/sub 6\\/ molecules and clusters in supersonic expansion  

Microsoft Academic Search

A method of measuring SF\\/sub 6\\/ cluster formation and inhibition in pulsed supersonic expansion in the presence of intense electromagnetic radiation is presented. The characterization of the expansion of SF\\/sub 6\\/ molecules was done and, the extension of the collision region was determined. An improved unidimensional theory of supersonic expansion showed good agreement with the experimental results. The spectra of

V. J. T. Airoldi

1987-01-01

345

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

346

From GEM to electromagnetism  

NASA Astrophysics Data System (ADS)

In the first part of the present work, we focus on the theory of gravitoelectromagnetism (GEM), and we derive the full set of equations and constraints that the GEM scalar and vector potentials ought to satisfy. We discuss important aspects of the theory, such as the presence of additional constraints resulting from the field equations and gauge condition, the requirement of the time-independence of the vector potential and the emergence of additional terms in the expression of the Lorentz force. We also propose an alternative ansatz for the metric perturbations that is found to be compatible only with a vacuum configuration but evades several of the aforementioned obstacles. In the second part of this work, we pose the question of whether a tensorial theory using the formalism of General Relativity could re-produce the theory of Electromagnetism. We demonstrate that the full set of Maxwell's equations can be exactly re-produced for a large class of models, but the framework has several weak points common with those found in GEM.

Bakopoulos, A.; Kanti, P.

2014-06-01

347

Electromagnetism of Bacterial Growth  

NASA Astrophysics Data System (ADS)

There has been increasing concern from the public about personal health due to the significant rise in the daily use of electrical devices such as cell phones, radios, computers, GPS, video games and television. All of these devices create electromagnetic (EM) fields, which are simply magnetic and electric fields surrounding the appliances that simultaneously affect the human bio-system. Although these can affect the human system, obstacles can easily shield or weaken the electrical fields; however, magnetic fields cannot be weakened and can pass through walls, human bodies and most other objects. The present study was conducted to examine the possible effects of bacteria when exposed to magnetic fields. The results indicate that a strong causal relationship is not clear, since different magnetic fields affect the bacteria differently, with some causing an increase in bacterial cells, and others causing a decrease in the same cells. This phenomenon has yet to be explained, but the current study attempts to offer a mathematical explanation for this occurrence. The researchers added cultures to the magnetic fields to examine any effects to ion transportation. Researchers discovered ions such as potassium and sodium are affected by the magnetic field. A formula is presented in the analysis section to explain this effect.

Ainiwaer, Ailiyasi

2011-10-01

348

Electromagnetic Launch to Space  

NASA Astrophysics Data System (ADS)

Many advances in electromagnetic (EM) propulsion technology have occurred in recent years. Linear motor technology for low-velocity and high-mass applications is being developed for naval catapults. Such technology could serve as the basis for a first-stage booster launch--as suggested by the US National Aeronautics and Space Administration (NASA) in the Maglifter concept. Using railguns, laboratory experiments have demonstrated launch velocities of 2-3 km/s and muzzle energies > 8 MJ. The extension of this technology to the muzzle velocities ( 7500 m/s) and energies ( 10 GJ) needed for the direct launch of payloads into orbit is very challenging but may not be impossible. For launch to orbit, even long launchers (> 1000 m) would need to operate at accelerations > 1000 G to reach the required velocities, so it would only be possible to launch rugged payloads, such as fuel, water, and materiel. Interest is being shown in such concepts by US, European, Russian, and Chinese researchers. An intermediate step proposed in France could be to launch payloads to sounding rocket altitudes for ionospheric research.

McNab, I. R.

349

SOLAR NANTENNA ELECTROMAGNETIC COLLECTORS  

SciTech Connect

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

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

2008-08-01

350

Polarimetry of electromagnetic materials  

NASA Astrophysics Data System (ADS)

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

Asahi, Toru; Osaka, Tetsuya; Kobayashi, Jinzo

2001-07-01

351

Electromagnetic Navigational Bronchoscopy  

PubMed Central

Despite advances in technology and treatment options, lung cancer remains a deadly disease. National screening programs are being instituted in an attempt to discover lung cancer in high-risk individuals at an earlier stage. Such screening programs invariably discover small peripheral nodules that previously would not have been clinically apparent; the management of such lesions can be challenging. Current diagnostic options such as percutaneous biopsy are effective; however, they are hindered by their risk of morbidity such as pneumothorax. Electromagnetic bronchoscopy (ENB) is an emerging technology that allows the practitioner the ability to both sample and treat small peripheral pulmonary lesions. In experienced centers, ENB provides high rates of diagnostic yield for small lesions and a complication rate significantly lower than that of more conventional diagnostic modalities. Although there are current barriers to its widespread utilization (cost, specialized imaging, technical training), these obstacles will handled similarly to any other emerging technology and will likely not be long-term impediments to its use. PMID:24436528

Port, Jeffrey; Harrison, Sebron

2013-01-01

352

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

353

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

354

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

355

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

Microsoft Academic Search

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

Theodore A. Welton

1948-01-01

356

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

357

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

358

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

359

Energy harvesting devices for harvesting energy from terahertz 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.; Kotter, Dale K.; Pinhero, Patrick J.

2012-10-09

360

Synthetic spectra of CP stars compared with UVES spectra  

NASA Astrophysics Data System (ADS)

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

Castelli, F.; Hubrig, S.

2008-04-01

361

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

362

Background noise spectra of global seismic stations  

SciTech Connect

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

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

1996-08-01

363

Electromagnetic and electrostatic emissions from a thin electron beam in space plasma  

NASA Astrophysics Data System (ADS)

Electromagnetic and electrostatic emissions from a spatially confined thin electron beam in a space plasma is studied via electromagnetic particle simulations. We assumed a top-hat ion density model to compensate an excess charge induced by an electron beam injection to identify an effect of current injection from a charge injection effect. At the onset of an electron beam injection, impulsive electromagnetic waves are radiated, propagating away from the electron beam. The simulation system is a two-dimensional x-y plane with both a static magnetic field and an electron beam drift in the y-direction. Boundary conditions are open in the x-direction and periodic in the y-direction. The electromagnetic waves can propagate without reflection at the x-boundaries where a masking method is used to absorb outgoing waves. An instability similar to the conventional two-stream instability in a uniform beam-plasma system develops after the initial response, and beam electrons are diffused. During this quasi-steady period, both electromagnetic and electrostatic waves are excited through the Landau resonance with beam electrons. Electrostatic emissions are confined to a region close to the electron beam, while the electromagnetic emissions propagate away from the beam depending on wave normal angles relative to a static magnetic field. Spatial configuration of the electromagnetic wave spectra shows a close resemblance to a funnel shaped VLF emissions observed in the Spacelab-2 electron beam experiment.

Omura, Yoshiharu; Matsumoto, Hiroshi

1988-04-01

364

Observation and theoretical simulation of electromagnetically induced transparency and enhanced velocity selective optical pumping in cesium vapour in a micrometric thickness optical cell  

NASA Astrophysics Data System (ADS)

Observation of electromagnetically induced transparency (EIT) and enhanced velocity selective optical pumping (VSOP) signals in a micrometric cell with cesium is reported. The line shape and non-linear 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 profile. A theoretical model based on five level optical Bloch equations is used to simulate the spectra. The Doppler convolution includes all possible orientations of atomic velocities with respect to the laser beam direction. Atoms moving nearly parallel to the windows and perpendicular to the collinear pump and probe beams have much lower Doppler shift and hence produce 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. 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 detuning of the pump frequency on the non-linear features is also reproduced by the simulation.

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

2014-09-01

365

Experimental evidence of electromagnetic pollution of ionosphere  

NASA Astrophysics Data System (ADS)

The Earth’s ionosphere responds to external perturbations originated mainly in the Sun, which is the primary driver of the space weather (SW). But solar activity influences on the ionosphere and the Earth's atmosphere (i.e., the energy transfer in the direction of the Sun-magnetosphere-ionosphere-atmosphere-surface of the Earth), though important, is not a unique factor affecting its state - there is also a significant impact of the powerful natural and anthropogenic processes, which occur on the Earth’s surface and propagating in opposite direction along the Earth’s surface-atmosphere-ionosphere-magnetosphere chain. Numerous experimental data confirm that the powerful sources and consumers of electrical energy (radio transmitters, power plants, power lines and industrial objects) cause different ionospheric phenomena, for example, changes of the electromagnetic (EM) field and plasma in the ionosphere, and affect on the state of the Earth atmosphere. Anthropogenic EM effects in the ionosphere are already observed by the scientific satellites and the consequences of their impact on the ionosphere are not currently known. Therefore, it is very important and urgent task to conduct the statistically significant research of the ionospheric parameters variations due to the influence of the powerful man-made factors, primarily owing to substantial increase of the EM energy production. Naturally, the satellite monitoring of the ionosphere and magnetosphere in the frequency range from tens of hertz to tens of MHz with wide ground support offers the best opportunity to observe the EM energy release, both in the global and local scales. Parasitic EM radiation from the power supply lines, when entering the ionosphere-magnetosphere system, might have an impact on the electron population in the radiation belt. Its interaction with trapped particles will change their energy and pitch angles; as a result particle precipitations might occur. Observations of EM emission by multiple low orbiting satellites have confirmed a significant increase in their intensity over the populated areas of Europe and Asia. Recently, there are many experimental evidences of the existence of power line harmonic radiation (PLHR) in the ionosphere. Their spectra consist of succession of 50 (60) Hz harmonics which is accompanied by a set of lines separated by 50 (60) or 100 (120) Hz - the central frequency of which is shifted to high frequency. These lines cover rather wide band - according to the available experimental data, their central frequencies are observed from ~1.5 - 3 kHz up to 15 kHz, and recently the main mains frequencies are also observed. The examples of power line harmonic radiation, which were detected by “Sich-1M”, “Chibis-M” and “Demeter” satellites, have been presented and discussed. The available experimental data, as well as theoretical estimations, allow us with a high degree of certainty to say that the permanent satellite monitoring of the ionospheric and magnetospheric anthropogenic EM perturbations is necessary for: a) objective assessment and prediction of the space weather conditions; b) evaluation of the daily or seasonal changes in the level of energy consumption; c) construction of a map for estimation of near space EM pollution. This study is partially supported by SSAU contract N 4-03/13.

Pronenko, Vira; Korepanov, Valery; Dudkin, Denis

366

Dressed-atom multiphoton analysis of anomalous electromagnetically induced absorption.  

PubMed

A method to interpret probe spectra of driven degenerate atomic systems is discussed. The dressed-atom multiphoton spectroscopy (DAMS) is based on a dressing of the atomic system with the strong coupling field, followed by a perturbative treatment of the probe field interaction. As an example, we apply the DAMS to provide a clear interpretation for anomalous electromagnetically induced absorption (EIA), which cannot be explained by spontaneous transfer of coherence. We show that anomalous EIA arises from quantum interference among competing two-photon transitions and explain the different dependences on the coupling field strength observed for various angular momentum setups. PMID:20867096

Chou, Hsiang-Shun; Evers, Jörg

2010-05-28

367

Dressed-Atom Multiphoton Analysis of Anomalous Electromagnetically Induced Absorption  

NASA Astrophysics Data System (ADS)

A method to interpret probe spectra of driven degenerate atomic systems is discussed. The dressed-atom multiphoton spectroscopy (DAMS) is based on a dressing of the atomic system with the strong coupling field, followed by a perturbative treatment of the probe field interaction. As an example, we apply the DAMS to provide a clear interpretation for anomalous electromagnetically induced absorption (EIA), which cannot be explained by spontaneous transfer of coherence. We show that anomalous EIA arises from quantum interference among competing two-photon transitions and explain the different dependences on the coupling field strength observed for various angular momentum setups.

Chou, Hsiang-Shun; Evers, Jörg

2010-05-01

368

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

NASA Astrophysics Data System (ADS)

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.; Jazi, B.; Heidari-Semiromi, E.

2014-09-01

369

The Spectrum of Electromagnetic Jets from Kerr Black Holes and Naked Singularities in the Teukolsky Perturbation Theory  

E-print Network

We give a new theoretical basis for examination of the presence of the Kerr black hole (KBH) or the Kerr naked singularity (KNS) in the central engine of different astrophysical objects around which astrophysical jets are typically formed: X-ray binary systems, gamma ray bursts (GRBs), active galactic nuclei (AGN), etc. Our method is based on the study of the exact solutions of the Teukolsky master equation for electromagnetic perturbations of the Kerr metric. By imposing original boundary conditions on the solutions so that they describe a collimated electromagnetic outflow, we obtain the spectra of possible {\\em primary jets} of radiation, introduced here for the first time. The theoretical spectra of primary electromagnetic jets are calculated numerically. Our main result is a detailed description of the qualitative change of the behavior of primary electromagnetic jet frequencies under the transition from the KBH to the KNS, considered here as a bifurcation of the Kerr metric. We show that quite surprisingly the novel spectra describe linearly stable primary electromagnetic jets from both the KBH and the KNS. Numerical investigation of the dependence of these primary jet spectra on the rotation of the Kerr metric is presented and discussed.

Denitsa R. Staicova; Plamen P. Fiziev

2010-02-02

370

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

371

Electromagnetic cavity effects from transmitters inside a launch vehicle fairing  

Microsoft Academic Search

This paper provides insight into the complicated issue of launch vehicle resonate cavity effects that has applicability outside of the space industry. Radiation from spacecraft or launch vehicle antennas located within the enclosures of a launch vehicle generates an electromagnetic environment that is difficult to predict accurately. This paper discusses the test results of power levels produced by a transmitter

Dawn H. Trout; Parveen F. Wahid; James E. Stanley

2009-01-01

372

Correlated quantum memory: Manipulating atomic entanglement via electromagnetically induced transparency  

Microsoft Academic Search

We propose a feasible scheme of quantum state storage and manipulation via electromagnetically induced transparency in flexibly united multiensembles of three-level atoms. For different atomic array configurations, one can properly steer the signal and the control lights to generate different forms of atomic entanglement within the framework of linear optics. These results opens up new possibility for the future design

Hui Jing; Xiong-Jun Liu; Mo-Lin Ge; Ming-Sheng Zhan

2005-01-01

373

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

374

FOREWORD: Special section on electromagnetic characterization of buried obstacles  

Microsoft Academic Search

This Inverse Problems special section on electromagnetic characterization of buried obstacles contains a selection of 14 invited papers, involving 41 authors and 19 research groups worldwide. (Though this section consists of invited papers, the standard refereeing procedures of Inverse Problems have been rigorously observed.) We do not claim to have reached all the high-level researchers in the field, but we

Dominique Lesselier; Weng Cho Chew

2004-01-01

375

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

376

IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY, VOL. 42, NO. 1, FEBRUARY 2000 97 Nonlinear EMI Simulation of an AM Detector at the  

E-print Network

IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY, VOL. 42, NO. 1, FEBRUARY 2000 97 Nonlinear EMI compatibility and electromagnetic interference (EMC/EMI) simula- tion up to the baseband signal processing path, system-level simulation. I. INTRODUCTION Nowadays, the importance of electromagnetic compatibility

Loyka, Sergey

377

Site frequency spectra from genomic SNP surveys.  

PubMed

Genomic survey data now permit an unprecedented level of sensitivity in the detection of departures from canonical evolutionary models, including expansions in population size and selective sweeps. Here, we examine the effects of seemingly subtle differences among sampling distributions on goodness of fit analyses of site frequency spectra constructed from single nucleotide polymorphisms. Conditioning on the observation of exactly two alleles in a random sample results in a site frequency spectrum that is independent of the scaled rate of neutral substitution (theta). Other sampling distributions, including conditioning on a single mutational event in the sample genealogy or randomly selecting a single mutation from a genealogy with multiple mutations, have distinct site frequency spectra that show highly significant departures from the predictions of the biallelic model. Some aspects of data filtering may contribute to significant departures of site frequency spectra from expectation, apart from any violation of the standard neutral model. PMID:19371756

Ganapathy, Ganeshkumar; Uyenoyama, Marcy K

2009-06-01

378

Electromagnetic compatibility in semiconductor manufacturing  

SciTech Connect

Electromagnetic Interference (EMI) causes problems in semiconductor manufacturing facilities that range from nuisances to major disruptions of production. In many instances, these issues are addressed in a reactionary rather than proactive manner by individuals who do not have the experience or the equipment necessary to combat EMI problems in a timely, cost effective manner. This approach leads to expensive retrofits, reduced equipment availability, long recovery times, and in some cases, line yield impacts. The goal of electromagnetic compatibility (EMC) in semiconductor manufacturing is to ensure that semiconductor process, metrology, and support equipment operate as intended without being affected by electromagnetic disturbances either transmitted through air (radiated interference), or transferred into the equipment via a conductive media (conducted interference). Rather than being neglected until serious issues arise, EMC should be considered in the early stages of facility design, in order to gain the most benefit at the lowest cost.

Montoya, J.A. [Intel Corp., Hillsboro, OR (United States)

1995-12-31

379

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

380

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

381

Continuum Fitting HST QSO Spectra  

NASA Technical Reports Server (NTRS)

The Principal Component Analysis (PCA) method which we are using to fit and describe QSO spectra relies upon the fact that QSO continuum are generally very smooth and simple except for emission and absorption lines. To see this we need high signal-to-noise (S/N) spectra of QSOs at low redshift which have relatively few absorption lines in the Lyman-a forest. We need a large number of such spectra to use as the basis set for the PCA analysis which will find the set of principal component spectra which describe the QSO family as a whole. We have found that too few HST spectra have the required S/N and hence we need to supplement them with ground based spectra of QSOs at higher redshift. We have many such spectra and we have been working to make them suitable for this analysis. We have concentrated on this topic since 12/15/01.

Tytler, David; Oliversen, Ronald J. (Technical Monitor)

2002-01-01

382

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

383

[Infrared and Raman spectra study on Tianhuang].  

PubMed

The Tianhuang stones, from Shoushan in China, were studied by using X-ray powder diffractometry (XRD), infrared (IR) spectroscopy and Raman spectroscopy to obtain the spectra characterization. Wave numbers 3621, 3629 and 3631 cm(-1) in the IR spectra and 3626, 3627 and 3632 cm(-1) in the Raman spectra are the characteristic peaks of dickitic Tianhuang, nacritic Tianhuang and illitic Tianhuang, respectively. Raman spectra assigned to OH are in good agreement with the IR results at 3550 -3750 cm(-1). Dickitic Tianhuang includes ordered dickite and disordered dickite. Compared with ordered dickite, the band assigned to OH3 of disordered dickite shifts to low-frequency by 8 cm(-1) and the relative intensity becomes stronger. The disorder structure may relate to the high level of Fe. The IR absorption spectra of nacritic Tianhuang superimposes strong peaks of dickite, indicating that IR absorption bands of dickite are stronger than that of nacrite at 3550-3750 cm(-1). The main mineral composition of illitic Tianhuang is 2M(1), while illite Tianhuang contains a small amount of 1M. All these characters provide a theoretical basis for the scientific identification of Tianhuang. PMID:23156769

Liu, Yun-gui; Chen, Tao

2012-08-01

384

Electromagnetic Models of Extragalactic Jets  

NASA Astrophysics Data System (ADS)

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.

2007-07-01

385

Gauge invariant fractional electromagnetic fields  

NASA Astrophysics Data System (ADS)

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

Lazo, Matheus Jatkoske

2011-09-01

386

Introduction to The Electromagnetic Spectrum  

NSDL National Science Digital Library

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

2009-10-05

387

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

388

Holographic Estimate of Electromagnetic Mass  

E-print Network

Using the gauge/gravity duality, we calculate the electromagnetic contributions to hadron masses, where mass generates dynamically by strong QCD interactions. Based on the Sakai-Sugimoto model of holographic QCD we find that the electromagnetic mass of proton is 0.48 MeV larger than that of neutron, which is in agreement with recent lattice results. Similarly for pions we obtain $m_{\\pi^{\\pm}}-m_{\\pi^0}$=4.1 ~ 5.4 MeV, close to the experimental value.

Hong, Deog Ki

2014-01-01

389

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

390

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

391

Electromagnetic control of coupled droplets  

NASA Astrophysics Data System (ADS)

Electromagnetism offers several advantages for moving capillary surfaces, including energy efficiency, fast response, and device integrability. Here, we demonstrate electromagnetic control of a pinned-contact, coupled droplet system using aqueous ferrofluids. A time-varying magnetic field provides the necessary perturbation to toggle millimeter scale capillary switches. Furthermore, periodic magnetic fields can drive coupled droplets at resonant frequencies approaching 100 Hz using only 1 V by balancing capillary forces with liquid inertia. These addressable devices may find applications in adaptive optics, fluidic actuators, and read-write arrays.

Malouin, Bernard A.; Vogel, Michael J.; Hirsa, Amir H.

2010-05-01

392

Unifit 2002universal analysis software for photoelectron spectra  

Microsoft Academic Search

The current level of development of the spectra analysis software Unifit for Windows is presented and evaluated by checking with test spectra. The program is characterized and the correctness of the numerical routines is demonstrated for the particular cases of the Shirley type background model and the Gaussian-Lorentzian product model functions. Different approaches to an optimum fit result are suggested.

R. Hesse; T. Chassé; R. Szargan

2003-01-01

393

Empirical continuum modeling for IUE low-dispersion spectra  

NASA Technical Reports Server (NTRS)

A numerical procedure for empirically determining a 'continuum' level in low-dispersion spectra from the IUE is described. The technique was developed for the automated fitting of SWP-LO (1150 A - 2000 A) spectra of stars of late spectral type, but it is more widely applicable.

Bennett, Jeffrey O.; Ayres, Thomas R.

1988-01-01

394

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

395

Bathymetry, electromagnetic streamlines and the marine controlled source electromagnetic method  

NASA Astrophysics Data System (ADS)

Seafloor topography must influence the strength and direction of electromagnetic fields generated during deep ocean controlled source electromagnetic surveying. Neither mathematical equation nor rules of thumb provide a clear perspective of how changes in water column thickness alters electromagnetic fields that engulf hundreds of cubic kilometres of air, ocean, host and reservoir. We use streamline visualisation to provide a generalised representation of how electromagnetic fields propagate into a 2D geo-electrical setting that includes strong bathymetry. Of particular interest are: (i)' dead zones' where electric fields at the ocean floor are demonstrated to be weak and (ii) the 'airwave' that appears in the electric field streamlines as circulating vortices with a shape that is clearly influenced by changes in ocean depth. Our analysis of the distribution of electric fields for deep and shallow water examples alludes to potential benefits from placement of receivers and/or transmitters higher in the water column as is the case for towed receiver geometries. Real-time streamline representation probably holds the most value at the survey planning stage, especially for shallow water marine EM surveys where ocean bottom topography is likely to be consequential.

Pethick, Andrew 12Harris, Brett

2014-07-01

396

Electromagnetic formation flight dipole solution planning  

E-print Network

Electromagnetic Formation Flight (EMFF) describes the concept of using electromagnets (coupled with reaction wheels) to provide all of the necessary forces and torques needed to maintain a satellite's relative position and ...

Schweighart, Samuel A. (Samuel Adam), 1977-

2005-01-01

397

Visible Light and the Electromagnetic Spectrum  

NSDL National Science Digital Library

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

Integrated Teaching And Learning Program

398

Quantized electromagnetic tornado in pulsar vacuum gap  

E-print Network

Quantized electromagnetic tornado in pulsar vacuum gap Giant pulses Regular radiation 1937+21 By A of the electromagnetic tornado. The quasi-classical and exact quantization of this rotation is possible. 9 #12;Possible

Fominov, Yakov

399

Electromagnetically Restrained Lithium Blanket APEX Interim Report November, 1999  

E-print Network

Electromagnetically Restrained Lithium Blanket APEX Interim Report November, 1999 6-1 CHAPTER 6: ELECTROMAGNETICALLY RESTRAINED LITHIUM BLANKET Contributors Robert Woolley #12;Electromagnetically Restrained Lithium Blanket APEX Interim Report November, 1999 6-2 6. ELECTROMAGNETICALLY RESTRAINED LITHIUM BLANKET 6

California at Los Angeles, University of

400

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

401

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

402

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.

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

2014-01-01

403

Interpretation of Fe-XANES Pre-Edge Spectra: Predictions Based on Co and Fe Optical Spectra  

NASA Technical Reports Server (NTRS)

Microanalysis of Fe-3+/Total(Fe) in extraterrestrial samples is important due to sample size constraints of sample return missions. We compare Fe XANES spectra with Co optical spectra that predict valence electron levels based on 'Z1' model. Additional information is contained in the original extended abstract.

Dyar, M. D.; Rossman, G. R.; Delaney, J. S.; Sutton, S. R.; Newville, M.

2001-01-01

404

Project based electromagnetics education  

Microsoft Academic Search

This paper describes a comprehensive project based EM program that allows for independent thinking, builds design and analytical skills and trains students in state-of-art design procedures. It begins with incorporating software projects and measurement techniques in a junior level course on wave theory and transmission lines that lead to more complex software projects and to designing experiments in the graduate

Jayanti Venkataraman

2009-01-01

405

Electronics and Electromagnetism  

NASA Astrophysics Data System (ADS)

Multilayer ceramic capacitors (MLCC) are the capacitors most commonly used in electronic circuits (television, radio, telephone, automobile, aeronautics, space, etc.). The main advantages are low cost, small size, a good level of chemical inertness, due to the fact that they are made from chemically very stable oxide ceramics, and hence good stability in time.

Nièpce, J.-C.; Givord, D.

406

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

407

Electromagnetic effects on geodesic acoustic modes  

NASA Astrophysics Data System (ADS)

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 ?e, the safety factor q, and the temperature ratio ? on GAM dispersion are analyzed.

Bashir, M. F.; Smolyakov, A. I.; Elfimov, A. G.; Melnikov, A. V.; Murtaza, G.

2014-08-01

408

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.

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

2014-06-01

409

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

Microsoft Academic Search

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

Liu Shaoke; Guo Zhongjun; Chen Guirong

2010-01-01

410

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

411

Why Study Electromagnetics: The First Unit in an Undergraduate Electromagnetics Course  

E-print Network

1 Why Study Electromagnetics: The First Unit in an Undergraduate Electromagnetics Course Allen unification of electric and magnetic fields predicting electromagnetic wave phenomena which Nobel Laureate: "Of what relevance is the study of electromagnetics to our modern society?" The goal of this unit

Taflove, Allen

412

Near infrared and ultraviolet spectra of TLEs  

NASA Astrophysics Data System (ADS)

We have found that sprites, beads and halos have similar optical spectra, but measurable differences in the near IR and near UV spectra. In particular, near infrared (NIR) and ultraviolet (UV) spectra of sprites, halos and beads corresponding to the first (1PG) and second positive (2PG) bands of N2 have been calculated for different observation altitudes from mountains (3.25 km) to airplanes (14 km), balloons (35 km) and space (nadir) platforms. The calculated non-equilibrium vibrational distribution functions (VDF) of the N2(B3?g) states in halos and beads show that the calculated NIR emissions produced through strong N2-1PG (B3?g ? A3?u+) transitions differ from the calculated sprite spectral emission patterns at ˜888 nm but particularly pronounced differences are found in the NIR spectral region at ˜1046 nm and ˜1231 nm corresponding to the N2-1PG (0,0) and (0,1) transitions, respectively. The blue - near UV spectra from N2-2PG (C3?u ? B3?g) transitions in halos and beads also exhibits slightly different spectral features when compared to the blue - near UV spectrum of sprites for bands originating from higher v-levels (v > 0) although they might not be above electronic noise level to be distinguished.

Gordillo-Vázquez, F. J.; Luque, A.; Simek, M.

2012-05-01

413

Energy spectra of quantum rings.  

PubMed

Quantum mechanical experiments in ring geometries have long fascinated physicists. Open rings connected to leads, for example, allow the observation of the Aharonov-Bohm effect, one of the best examples of quantum mechanical phase coherence. The phase coherence of electrons travelling through a quantum dot embedded in one arm of an open ring has also been demonstrated. The energy spectra of closed rings have only recently been studied by optical spectroscopy. The prediction that they allow persistent current has been explored in various experiments. Here we report magnetotransport experiments on closed rings in the Coulomb blockade regime. Our experiments show that a microscopic understanding of energy levels, so far limited to few-electron quantum dots, can be extended to a many-electron system. A semiclassical interpretation of our results indicates that electron motion in the rings is governed by regular rather than chaotic motion, an unexplored regime in many-electron quantum dots. This opens a way to experiments where even more complex structures can be investigated at a quantum mechanical level. PMID:11677600

Fuhrer, A; Lüscher, S; Ihn, T; Heinzel, T; Ensslin, K; Wegscheider, W; Bichler, M

2001-10-25

414

Camera artifacts in IUE low-dispersion spectra  

NASA Technical Reports Server (NTRS)

Sky-background images obtained by the International Ultraviolet Explorer (IUE) were analyzed to study artificial spectral features (camera artifacts) in low-dispersion spectra. The artifacts mimic emission features and have been present in long-exposure spectra since the launch of the IUE satellite. The camera artifacts are strong in spectra characterized by long exposure times because they scale in time-integrated flux with the background level, which increases during the exposure due to camera phosphorescence. The artifacts cannot be detected in spectra obtained from short, direct exposures of flat-field lamps or standard stars. Plots of average sky-background spectra for the three operational IUE cameras (SWP, LWP, and LWR) are given to aid scientists in the identification of artifacts in their spectra.

Crenshaw, D. Michael; Norman, Dara J.; Bruegman, Otto W.

1990-01-01

415

Pulsed power for electromagnetic launching  

Microsoft Academic Search

There are system advantages to producing power for electromagnetic propulsion by real time generation rather than by a sequence of generation-storage-switching. The best type of generator for this purpose is the flux compression generator. Different types of flux compression generator which have been developed at Sandia National Laboratories are reviewed and their applications to electric launching are discussed. New experimental

M. Cowan

1982-01-01

416

Electromagnetic generators for power harvesting  

Microsoft Academic Search

The design of electromagnetic generators that can be integrated within shoe soles is described. In this way, parasitic energy expended by a person when walking can be tapped and used to power portable electronic equipment. Designs are based on discrete permanent magnets and copper wire coils, and it is intended to improve performance by applying micro-fabrication technologies. Detailed descriptions of

M. Duffy; D. Carroll

2004-01-01

417

Inertia, Electromagnetism and Fluid Dynamics  

Microsoft Academic Search

It is shown that the vector potential created by a charged particle in motion acts as an ideal space flow that surrounds the particle. The interaction between the particle and the entrained space flow gives rise to the observed properties of inertia and the relativistic increase of mass. Parallels are made between the inertia property of matter, electromagnetism and the

Alexandre A. Martins; Mario J. Pinheiro

2008-01-01

418

Proposed electromagnetic wave energy converter  

NASA Technical Reports Server (NTRS)

Device converts wave energy into electric power through array of insulated absorber elements responsive to field of impinging electromagnetic radiation. Device could also serve as solar energy converter that is potentially less expensive and fragile than solar cells, yet substantially more efficient.

Bailey, R. L.

1973-01-01

419

The theory of electromagnetic levitation  

Microsoft Academic Search

Identifies a number of fundamental principles of physics which are involved in applying electromagnetic suspensions to transport. The theory relating to these is developed and typical values are given for important variables and parameters when an overall view of the transport system is taken. A number of simplifications and assumptions are used in order to treat as concisely as possible

R. Goodall

1985-01-01

420

Finite formulation of electromagnetic field  

Microsoft Academic Search

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

Enzo Tonti; Piazzale Europa

2002-01-01

421

Explanations, Education, and Electromagnetic Fields.  

ERIC Educational Resources Information Center

Explaining complex scientific and environmental subjects in the mass media is difficult to do, particularly under such constraints as short deadlines and lack of space or time. When a scientific controversy and human health risk are involved, this becomes an even harder task to accomplish. The subject of electromagnetic fields (EMF) involves…

Friedman, Sharon M.

422

The Electromagnetic Spectrum: Resonating Atmosphere  

NSDL National Science Digital Library

Using a paper and tape device, students experience how atoms and molecules of gas in Earthâs atmosphere absorb electromagnetic energy through resonance. This activity is part of Unit 2 in the Space Based Astronomy guide that contains background information, worksheets, assessments, extensions, and standards.

423

Electromagnetic test facilities at Sandia National Laboratories  

Microsoft Academic Search

The paper describes major electromagnetic test facilities at Sandia National Laboratories; each has undergone recent upgrades. The paper discusses each facility, their uses, and upgrades pertaining to the facilities performance and diagnostic capabilities. The facilities discussed are the Sandia lightning simulator, the electromagnetic environments simulator (a large TEM cell), the mode-stirred chamber, and the anechoic chamber. Sandia's expertise in electromagnetics

Michele Caldwell; Matthew B. Higgins

2005-01-01

424

EE4391A Electromagnetic Compatibility Summer 2004  

E-print Network

EE4391A Electromagnetic Compatibility Summer 2004 Instructor: Dr. W. Marshall Leach, Jr., Van Leer compatibility and the agencies which write these regulations. To examine the electromagnetic properties on electromagnetic compatibility. To examine the benefits of using balanced signals and the methods of power supply

Leach Jr.,W. Marshall

425

CONDUCTED EMISSIONS TESTING FOR ELECTROMAGNETIC COMPATIBILITY  

E-print Network

CONDUCTED EMISSIONS TESTING FOR ELECTROMAGNETIC COMPATIBILITY Maximilian Moy Lockheed Martin, 1801 range is creating an increased need for electromagnetic compatibility (EMC) testing. In the United.4-2001 [2] was the primary guide used for the design of the system. Electromagnetic compatibility references

Arakaki, Dean Y.

426

Electromagnetic driving units for complex microrobotic systems  

Microsoft Academic Search

Electromagnetic actuators play an important role in macroscopic robotic systems. In combination with motion transformers, like reducing gear units, angular gears or spindle-screw drives, electromagnetic motors in large product lines ensure the rotational or linear motion of robot driving units and grippers while electromagnets drive valves or part conveyors. In this paper micro actuators and miniaturized motion transformers are introduced

Frank Michel; Wolfgang Ehrfeld; Udo Berg; Reinhard Degen; Felix Schmitz

1998-01-01

427

Numerical Analysis of Conducted Electromagnetic Interferences  

Microsoft Academic Search

Abstract—The split of the ,conducted Electromagnetic Interference noises into different modes, common and differential mode is important to the conducted Electromagnetic Interference modeling and appropriate application of mitigation techniques. A method of Electromagnetic Interference noise decomposition is based on algebraic calculations and the Fourier transform. The method can be useful in comparative analysis of the influence of inverter control algorithms

Eleonora Darie; Emanuel Darie

2008-01-01

428

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

429

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 plasmons with the same frequency as the outside electromagnetic waves but with a much shorter wavelength

Atwater, Harry

430

ABSORBING BOUNDARY CONDITIONS FOR ELECTROMAGNETIC WAVE PROPAGATION  

E-print Network

ABSORBING BOUNDARY CONDITIONS FOR ELECTROMAGNETIC WAVE PROPAGATION Xiaobing Feng y Abstract of the electromagnetic fields indi­ vidually. This boundary condition allows any wave motion generated within the domain, and the electromagnetic wave scattering related to antennas. Because of the limitations of both speed and memory

431

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

432

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

433

PERFECT ELECTROMAGNETIC CONDUCTOR (PEMC) AND FRACTIONAL WAVEGUIDE  

Microsoft Academic Search

Fractional curl operator has been utilized to study the fractional perfect electromagnetic conducting waveguide. The fractional perfect electromagnetic conducting waveguide may be regarded as intermediate step between the two given waveguides. One of the waveguide is composed of perfect electromagnetic conducting (PEMC) walls while other is dual of it as (DPEMC). Corresponding fields and surface impedance have been determined and

Akhtar Hussain; Qaisar A. Naqvi

2007-01-01

434

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

435

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

436

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

437

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

438

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

439

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

440

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

441

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

442

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

443

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

444

Plasmon Mapping in Metallic Nanostructures and its Application to Single Molecule Surface Enhanced Raman Scattering: Imaging Electromagnetic Hot-Spots and Analyte Location  

SciTech Connect

A major component of this proposal is to elucidate the connection between optical and electron excitation of plasmon modes in metallic nanostructures. These accomplishments are reported: developed a routine protocol for obtaining spatially resolved, low energy EELS spectra, and resonance Rayleigh scattering spectra from the same nanostructures.; correlated optical scattering spectra and plasmon maps obtained using STEM/EELS.; and imaged electromagnetic hot spots responsible for single-molecule surface-enhanced Raman scattering (SMSERS).

Camden, Jon P

2013-07-16

445

Three-photon electromagnetically induced transparency using Rydberg states.  

PubMed

We demonstrate electromagnetically induced transparency in a four-level cascade system where the upper level is a Rydberg state. The observed spectral features are sub-Doppler and can be enhanced due to the compensation of Doppler shifts with AC Stark shifts. A theoretical description of the system is developed that agrees well with the experimental results, and an expression for the optimum parameters is derived. PMID:23041883

Carr, Christopher; Tanasittikosol, Monsit; Sargsyan, Armen; Sarkisyan, David; Adams, Charles S; Weatherill, Kevin J

2012-09-15

446

Empirical calibration of infrared images of electromagnetic fields  

Microsoft Academic Search

An infrared (IR) measurement technique has been developed to measure electromagnetic (EM) fields. This technique produces a two-dimensional IR thermogram of the electric or magnetic field being measured, i.e., an isothermal contour map of the intensity of the EM field. The intensity levels (equi-color levels) of the IR thermograms are empirically calibrated using standard gain horn antennas at several frequencies,

John D. Norgard; Michael Seifert; Ronald M. Sega; Anthony Pesta

1995-01-01

447

Cosmology from quasar spectra  

NASA Astrophysics Data System (ADS)

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

Suzuki, Nao

2005-11-01

448

Beta decay and other processes in strong electromagnetic fields  

E-print Network

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

Evgeny Akhmedov

2010-11-16

449

Beta decay and other processes in strong electromagnetic fields  

SciTech Connect

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

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

2011-09-15

450

Photoelectron spectra in an autoionization system interacting with a neighboring atom  

E-print Network

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

Perina, Jan; Leonski, Wieslaw; Perinova, Vlasta

2011-01-01

451

Photoelectron spectra in an autoionization system interacting with a neighboring atom  

E-print Network

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

Jan Perina Jr; Antonin Luks; Wieslaw Leonski; Vlasta Perinova

2011-04-08

452

Photoelectron spectra in an autoionization system interacting with a neighboring atom  

SciTech Connect

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

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

2011-05-15

453

THERMAL NEUTRON SPECTRA IN GRAPHITE  

Microsoft Academic Search

A pulsed, high-current, electron linear accelerator is used to excite ; thermal-neutron spectra in a graphite asemmbly. The steady-state energy spectra ; of neutrons are measured at several temperatures by pulsed-beam time-of-flight ; techniques. The measured spectra are compared with theoretical predictions which ; use free- and bound-carbon scattering kernels. The scattering kernel for carbon ; bound in graphite is

D. E. Parks; J. R. Beyster; N. F. Wikner

1962-01-01

454

Ion Signatures in Supernova Spectra  

E-print Network

A systematic survey of ions that could be responsible for features in the optical spectra of supernovae is carried out. Six different compositions that could be encountered in supernovae are considered. For each composition, the LTE optical depth of one of the strongest optical lines of each ion is plotted against temperature. For each ion that can realistically be considered as a candidate to produce identifiable features in supernova spectra, a sample synthetic spectrum is displayed. The optical depth plots and the synthetic spectra can provide guidance to studies of line identifications in the optical spectra of all types of supernovae during their photospheric phases.

K. Hatano; D. Branch; A. Fisher; J. Deaton; E. Baron

1998-09-18

455

Interpreting Chromosome Aberration Spectra  

NASA Technical Reports Server (NTRS)

Ionizing radiation can damage cells by breaking both strands of DNA in multiple locations, essentially cutting chromosomes into pieces. The cell has enzymatic mechanisms to repair such breaks; however, these mechanisms are imperfect and, in an exchange process, may produce a large-scale rearrangement of the genome, called a chromosome aberration. Chromosome aberrations are important in killing cells, during carcinogenesis, in characterizing repair/misrepair pathways, in retrospective radiation biodosimetry, and in a number of other ways. DNA staining techniques such as mFISH ( multicolor fluorescent in situ hybridization) provide a means for analyzing aberration spectra by examining observed final patterns. Unfortunately, an mFISH observed final pattern often does not uniquely determine the underlying exchange process. Further, resolution limitations in the painting protocol sometimes lead to apparently incomplete final patterns. We here describe an algorithm for systematically finding exchange processes consistent with any observed final pattern. This algorithm uses aberration multigraphs, a mathematical formalism that links the various aspects of aberration formation. By applying a measure to the space of consistent multigraphs, we will show how to generate model-specific distributions of aberration processes from mFISH experimental data. The approach is implemented by software freely available over the internet. As a sample application, we apply these algorithms to an aberration data set, obtaining a distribution of exchange cycle sizes, which serves to measure aberration complexity. Estimating complexity, in turn, helps indicate how damaging the aberrations are and may facilitate identification of radiation type in retrospective biodosimetry.

Levy, Dan; Reeder, Christopher; Loucas, Bradford; Hlatky, Lynn; Chen, Allen; Cornforth, Michael; Sachs, Rainer

2007-01-01

456

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

457

Measurement and interpretation of plutonium spectra  

SciTech Connect

The atomic spectroscopic data available for plutonium are among the rickest of any in the periodic system. They include high-resolution grating and Fourier-transform spectra as well as extensive Zeeman and isotope-shift studies. We summarize the present status of the term analysis and cite the configurations that have been identified. A least-squares adjustment of a parametric Hamiltonian for configurations of both Pu I and Pu II has shown that almost all of the expected low levels are now known. The use of a model Hamiltonian applicable to both lanthanide and actinide atomic species has been applied to the low configurations of Pu I and Pu II making use of trends predicted by ab initio calculations. This same model has been used to describe the energy levels of Pu/sup 3 +/ in LaCl/sub 3/, and an extension has permitted preliminary calculations of the spectra of other valence states.

Blaise, J.; Fred, M.S.; Carnall, W.T.; Crosswhite, H.M.; Crosswhite, H.

1982-01-01

458

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

459

Projecting Spectra for Classroom Investigations.  

ERIC Educational Resources Information Center

Describes an inexpensive spectrum projector that makes high-dispersion, high-efficiency diffraction gratings using a holographic process. Discusses classroom applications such as transmission spectra, absorption spectra, reflection characteristics of materials, color mixing, florescence and phosphorescence, and break up spectral colors. (MDH)

Sadler, Philip

1991-01-01

460

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

461

Neural Network Classification of Stellar Spectra  

NASA Astrophysics Data System (ADS)

The MK classification system as first proposed in 1943 by Morgan, Keenan & Kellman (1943) has been an important tool in stellar and galactic astrophysics. Currently, MK classification is a useful approach to obtaining general information on stellar spectra and selecting stars for further study. However, the existing manual methods of obtaining classifications are slow, making it infeasible for them to be applied to the vast numbers of spectra which will be obtained in future spectral surveys. In this project I investigate the application of artificial neural networks to the automation of MK spectral classification. For the purposes of this project, I digitized and reduced 100 objective prism plates taken from the Michigan Spectral Survey (Houk 1994). Using software I developed, I extracted a set of over 5000 spectra at a resolution of ~3 AA covering the wavelength range 3800-5200 AA (Bailer-Jones, Irwin & von Hippel 1997a). These spectra were used in conjunction with their two-dimensional classifications listed in Michigan Henry Draper Catalogue (Houk & Smith-Moore 1988 and references therein) to develop supervised neural network classifiers. I show that neural networks can give accurate spectral type classifications (1 sigma = 0.82 subtypes, sigmaRMS = 1.09 subtypes) across the full range of spectral types present in the database (B2-M7); I show also that the networks yield correct luminosity classes for over 95% of both dwarfs and giants with a high degree of confidence (Bailer-Jones, Irwin & von Hippel 1997b). The high level of reproducibility of neural network classifications is demonstrated and an analysis of the effect of the complexity of the neural network on its classifications is given. For the purposes of many analyses, stellar spectra contain a large amount of redundant (correlated) information. I investigate the application of Principal Components Analysis (PCA) to the optimal compression of spectra. I show that PCA can compress the spectra by a factor of over 30 whilst retaining more than 95% of the variance in the data set. Furthermore, this compression leads to no decrease in classifier performance, indicating that the PCA compression from 820 to 25 components results in no significant loss of relevant information. I also demonstrate how PCA acts as a filter of noise and bogus features in a spectrum and can be used to identify unusual spectra. The ultimate goal of stellar classification should be a physical parameterization of the stars. I examine the application of neural networks to the problem of obtaining physical parameters (Teff, log g etc.) directly from an observed spectrum, by training a neural network on synthetic spectra and then applying it to observed spectra (Bailer-Jones et al. 1997). By determining physical parameters in this way, any assumptions and limitations of an intermediate classification scheme are avoided. However, I have used the effective temperature (Teff) inferred by the networks to produce an accurate calibration of the MK system for dwarf, giant and sub-giant stars, based on the set of 5000 observed spectra. This calibration agrees well with a number of calibrations published in the literature. It is demonstrated through the metallicity dependence of the derived temperature calibration that the neural networks are sensitive to the metallicity features in the observed spectra. With further work it is likely that neural networks will be able to determine metallicity reliably using only the optical stellar spectrum.

Bailer-Jones, C. A. L.

1997-08-01

462

Atonic Mechanics of H and He Spectra  

NASA Astrophysics Data System (ADS)

We have created a new and simpler way to calculate atomic spectra than could be done with conventional quantum mechanics. Accordingly, we coin the term atonic mechanics. Spectra of hydrogen and helium are calculated. Atonic mechanics results are compared with NIST Atomic Spectra Database Levels Data He I taken from the NIST web site. Exact agreement is obtained, as we use an effective mass coefficient, m3, to account for three-body effects. The ground state (configuration 1s2 - term 1S) value of m3 is 0.9506109 where we expect three-body effects are strongest. The largest value of m3 is 1.0000868 (configuration 1s.5s - term 1S). As the outer electron energy further increases, m3 decreases monotonically to 0.9999242 where three-body effects diminish. This is for configuration 1s.15s - term 1S, the most energetic state that we considered. Although it is not done here, atonic mechanics may provide a way for modeling multi-body effects using atomic spectra.

Phillips, Alfred

2004-03-01

463

Helium Spectra in Atonic Mechanics  

NASA Astrophysics Data System (ADS)

In our model of the helium atom, we postulate that the angular momentum of each electron divided by equals an integer, n, plus a fraction,?n. By minimizing the energy the energy of the helium atom, we find that the ?n values are a function of the total angular momenta, J, irrespective of the integer, n. We thus obtain a set of ?n values for the singlet and triplet states of helium. The ?n values are related to fractals. In our model, we made adjustments to the electron mass so that the calculated energy values agree with the seventeen values for the singlet 1s-ns configurations listed in NIST Atomic Spectra Database Levels Data. The adjustments to the electron mass were usually very close to unity except for the ground state for which the adjustment was ˜5%. (Adjustments like these suggest that we may be able to study three-body effects with spectral accuracy.) By doing this, we had good agreement with all of the NIST spectral values for helium (191 lines of He I, and 243 lines of He II). This conceptually and mathematically simple procedure can be used for other atoms.

Phillips, Alfred, Jr.

2008-03-01

464

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

465

Electromagnetic Activation of Capillary Switches  

NASA Astrophysics Data System (ADS)

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

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

2008-11-01

466

Anomalous absorption of electromagnetic radiation  

SciTech Connect

Transverse structure in a plasma at the critical layer can increase the coupling between electromagnetic and electrostatic waves and lead to enhanced absorption of the radiation. Simulations show cases of nearly 90% absorption of the incident energy. A ripple across the density gradient acts to focus the incoming electromagnetic radiation in the lower density regions coupling it to electrostatic modes through the transverse density gradients. A simple model of the absorption shows good agreement with the scalings observed in the computer simulations. Part of the reflected radiation is side scattered at {plus minus}{ital nk}{sub {ital t}}, where {ital k}{sub {ital t}} is the wave number of the transverse structure. This can reduce the directly backscattered radiation to 0.6% of the incident energy. Nonlinear coupling of the electrostatic waves leads to radiation at twice the incident frequency.

Rowland, H.L. (Space Plasma Branch, Plasma Physics Division, Naval Research Laboratory, Washington, D.C. 20375-5000 (United States))

1992-12-01

467

Electromagnetic Response of Weyl Semimetals  

NASA Astrophysics Data System (ADS)

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.

Vazifeh, M. M.; Franz, M.

2013-07-01

468

Falling Magnets and Electromagnetic Braking  

NASA Astrophysics Data System (ADS)

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

Culbreath, Christopher; Palffy-Muhoray, Peter

2009-03-01

469

Pulsed power for electromagnetic launching  

SciTech Connect

There are system advantages to producing power for electromagnetic propulsion by real-time generation rather than by a sequence of generation-storage-switching. The best type of generator for this purpose is the flux compression generator. Different types of flux compression generator which have been developed at Sandia National Laboratories are reviewed and their applications to electric launching are discussed. New experimental facilities for producing more powerful generators are described and cost comparisons are made.

Cowan, M

1980-12-01

470

Pulsed power for electromagnetic launching  

Microsoft Academic Search

There are system advantages to producing power for electromagnetic propulsion by real-time generation rather than by a sequence of generation-storage-switching. The best type of generator for this purpose is the flux compression generator which have been developed at Sandia National Laboratories are reviewed and their applications to electric launching are discussed. New experimental facilities for producing more powerful generators are

M. Cowan

1980-01-01

471

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

472

Electromagnetic calorimeter trigger at Belle  

NASA Astrophysics Data System (ADS)

The performance of CsI(T?) electromagnetic calorimeter trigger system in the Belle experiment is described. Two kinds of trigger schemes have been taken into account, namely a total energy trigger and a cluster counting trigger which are complementary to each other. In addition, the system has provided the online/offline luminosity information using the Bhabha event trigger scheme. An upgrade of the trigger is discussed.

Cheon, B. G.; Kim, Hee-Jong; Lee, S. H.; Won, E.; Park, I. C.; Hur, T. W.; Park, C. S.; Kim, S. K.; Kim, H. J.; Kim, H. O.; Chu, T. H.; Usov, Yu. V.; Aulchenko, V. M.; Kuzmin, A. S.; Bondar, A. E.; Shwartz, B.; Eidelman, S.; Krokovny, P.; Hayashii, H.; Sagawa, H.; Fukushima, M.

2002-11-01

473

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

474

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

475

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.

Zhao, L; Yelin, S F

2008-01-01

476

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

477

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

478

Electromagnetic scattering from biological tissue  

NASA Astrophysics Data System (ADS)

Based on the mathematical models of the experimentally fitted spectrum of index inhomogeneities, we analyze the electromagnetic field scattered from biological tissue. The resulting cross-spectral density matrices are expressed in spherical polar coordinates and the two-dimensional definition of polarization could be used. The results show that the polarization characteristics of the far scattered field depend closely on the types of the tissue.

Tong, Zhisong; Korotkova, Olga

2012-12-01

479

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

480

Electromagnetically induced transparency for x rays  

E-print Network

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

Buth, Christian; Young, Linda

2007-01-01