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1

AGS RESONANT EXTRACTION WITH HIGH INTENSITY BEAMS.  

SciTech Connect

The Brookhaven AGS third integer resonant extraction system allows the AGS to provide high quality, high intensity 25.5 GeV/c proton beams simultaneously to four target stations and as many as 8 experiments. With the increasing intensities (over 7 x 10{sup 13} protons/pulse) and associated longer spill periods (2.4 to 3 seconds long), we continue to run with low losses and high quality low modulation continuous current beams.[1] Learning to extract and transport these higher intensity beams has required a process of careful modeling and experimentation. We have had to learn how to correct for various instabilities and how to better match extraction and the transport lines to the higher emittance beams being accelerated in the AGS. Techniques employed include ''RF'' methods to smooth out momentum distributions and fine structure. We will present results of detailed multi-particle tracking modeling studies which enabled us to develop a clear understanding of beam loss mechanisms in the transport and extraction process. We will report on our status, experiences, and the present understanding of the intensity limitations imposed by resonant extraction and transport to fixed target stations.

AHRENS,L.; BROWN,K.; GLENN,J.W.; ROSER,T.; TSOUPAS,N.; VANASSELT,W.

1999-03-29

2

Third interger resonance slow extraction schemem for a mu->e experiment at Fermilab  

SciTech Connect

The current design of beam preparation for a proposed mu->e conversion experiment at Fermilab is based on slow resonant extraction of protons from the Debuncher. The Debuncher ring will have to operate with beam intensities of 3 x 10{sup 12} particles, approximately four orders of magnitude larger than its current value. The most challenging requirements on the beam quality are the spill uniformity and low losses in the presence of large space charge and momentum spread. We present results from simulations of third integer resonance extraction assisted by RF knock-out (RFKO), a technique developed for medical accelerators. Tune spreads up to 0.05 have been considered.

Nagaslaev, V.; Amundson, J.; Johnstone, J.; Michelotti, L.; Park, C.S.; Werkema, S.; /Fermilab; Syphers, M.; /Michigan State U.

2010-09-01

3

DESIGN OF A RESONANT EXTRACTION SYSTEM FOR THE AGS BOOSTER.  

SciTech Connect

The Booster Application Facility (BAF) will employ heavy ion beams of many different ion species and at beam energies ranging from 0.04 to 3.07 GeV/nucleon. Resonant extraction is required in order to deliver a continuous stream of particles. In this report we describe the beam requirements and the system design. The basic design is a third integer resonant extraction process which employs a single thin magnetic septum and a thick septum ejector magnet The expected extraction efficiency is about 85%, based on the thin septum thickness and the predicted step size of the resonant beam at the septum. This is more than sufficient for the low intensity low energy heavy ion beams needed for the BAF. In this report we will present a detailed discussion of the design of the various elements and a discussion of the detailed modeling of resonant extraction from the AGS Booster. The extraction process was modeled using a BNL version of MAD which allowed us to interactively observe detailed particle tracking of the process. This was a key tool to have in hand which permitted us to pose and answer various questions in a very short period of time.

BROWN,K.; CULLEN,J.; GLENN,J.W.; LEE,Y.Y.; MCNERNEY,A.; NIEDERER,J.; ROSER,T,; SOUKAS,A.; TUOZZOLO,J.; TSOUPAS,N.

1999-03-29

4

Preliminaries toward studying resonant extraction from the Debuncher  

SciTech Connect

A recent proposal to detect {mu} {yields} e direct conversion at Fermilab asks for slow extraction of protons from the antiproton source, specifically from the Debuncher. [1] A third-integer resonance originally was considered for this, partly because of the Debuncher's three-fold symmetry and partly because its operational horizontal tune, {nu}{sub x} {approx} 9.765, is already within 0.1 of {nu}{sub x} = 29/3. Using a half integer resonance, {nu}{sub x} = 19/2, though not part of the original proposal, has been suggested more recently because (a) Fermilab has had a good deal of experience with half-integer extraction from the Tevatron, the Main Injector and the erstwhile Main Ring, and (b) for reasons we shall examine later, it depopulates the entire bunch without an abort at the end. This memo presents considerations preliminary to studying both possibilities. It is meant only as a starting point for investigations to be carried out in the future. The working constraints and assumptions have oscillated between two extremes: (1) making minimal changes in the antiproton source to minimize cost and (2) building another machine in the same tunnel. In this memo we adopt an attitude aligned more toward the first. The assumed parameters are listed in Table 1. A few are not (easily) subject to change, such as those related to the beam's momentum and revolution frequency and the acceptance of the debuncher. Two resonance exemplars are presented in the next section, with an explanation of the analytic and semi-analytic calculations that can be done for each. Section 3 contains preliminary numerical work that was done to validate the exemplars within the context of extraction from the Debuncher. A final section contains a summary. Following the bibliography, appendices contain (a) a qualitative, conceptual discussion of extraction for the novice, (b) a telegraphic review of the perturbative incantations used to filter the exemplars as principal resonances of quadrupole, sextupole and octupole distributions, (c) a brief discussion of linearly independent control circuits, and (d) two files describing the antiproton source's rings in MAD v.8 format, not readily available elsewhere. All figures are located at the end. We emphasize again, the work reported here barely begins the effort that will be required to design, validate and perform resonant extraction from the Debuncher. Our goal was to compile these preliminary notes in one place for easy future reference, preferably by a young, intelligent, motivated and energetic graduate student.

Michelotti, Leo; Johnstone, John; /Fermilab

2009-06-01

5

Space charge effect of the high intensity proton beam during the resonance extraction for the Mu2e experiment at Fermilab  

SciTech Connect

The proposed Mu2e experiment to search for direct {mu} {yields} e conversion at Fermilab plans slow, resonant extraction of a beam with 3 x 10{sup 12} protons from the Debuncher ring. Space charge of this high intensity beam is a critical factor, since it induces significant betatron tune spread and consequently affects resonance extraction processes, such as spill uniformity and beam losses. This study shows the multi-particle simulation results in the early stages of resonance extraction and spill uniformity in the presence of 2D and 3D space charge effects. We have presented the results of the third-integer resonance extraction in early stage for the Mu2e experiment in the presence of space charge effects. In order to track particles and to calculate self-consistent space charge effects, Synergia2 was used, which is capable of parallel computing. The space charge tune shift was computed and was reasonable value compared with the analytical calculation. Locations of the septum and Lambertson were chosen so that particles are kicked and extracted efficiently. The spill rates for with and without space charge effects were uniform, but should be improved for the early stage after the sextupole field ramping.

Park, Chong Shik; Amundson, James; Johnstone, John; Michelotti, Leo; Nagaslaev, Vladimir; Werkema, Steve; /Fermilab

2011-03-01

6

Resonant beam extraction scheme with constant separatrix  

Microsoft Academic Search

A new scheme for resonant extraction with a constant separatrix is presented to realize small emittance, constant position and size of the extracted beam. In this scheme, the amplitude of the betatron oscillations inside the constant separatrix is increased by electromagnetic transverse or longitudinal perturbations, or scattering by other particles. Particles outside the separatrix are extracted through nonlinear resonance. The

Kazuo Hiramoto; Masatugu Nishi

1992-01-01

7

CONTINUOUS EXTRACTED BEAM IN THE AGS FAST EXTERNAL BEAM LINE.  

SciTech Connect

A method to split off a few percent of the 6 x 10{sup 13} AGS beam delivered to the Slow External Beam (SEB) lines and send it down the Fast External Beam line (FEB) has been developed. The mission is to feed a counter experiment off the FEB that directly measures the neutrino mass using the muon storage ring. The use of normal thin septum splitters would have an excessive loss overhead and been optically difficult. The AGS Slow Extraction uses a third integer resonance with sextuple strength so the resonance width is a few percent of the beam width. This results in a low density tail which will be clipped by a bent crystal and deflected into the FEB channel. This clipping off of the tail should reduce losses in the SEB transport line. Details of modeled orbits, particle distribution and extraction trajectories into and out off the crystal will be given.

GLENN,J.W.; TSOUPAS,N.; BROWN,K.A.; BIRYUKOV,V.M.

2001-06-18

8

Calculating resonances (natural frequencies) and extracting them from transient fields  

Microsoft Academic Search

Mathematical formulation and analysis of numerical methods for calculating the natural frequencies (resonances) are given. Stability of these methods towards roundoff errors and small perturbations of the obstacles is established. Some formulas for the variations of the natural frequencies due to small perturbations of the surface of the obstacle are given. A simple new method for extraction of resonances from

A. G. Ramm

1985-01-01

9

AGS slow extracted beam improvement  

SciTech Connect

The Brookhaven AGS is a strong focusing accelerator which is used to accelerate protons and various heavy ion species to an equivalent proton energy of 29 GeV. Since the late 1960`s it has been serving high energy physics (HEP - proton beam) users of both slow and fast extracted beams. The AGS fixed target program presently uses primary proton and heavy ion beams (HIP) in slowly extracted fashion over spill lengths of 1.5 to 4.0 seconds. Extraction is accomplished by flattoping the main and extraction magnets and exciting a third integer resonance in the AGS. Over the long spill times, control of the subharmonic amplitude components up to a frequency of 1 kilohertz is very crucial. One of the most critical contributions to spill modulation is due to the AGS MMPS. An active filter was developed to reduce these frequencies and it`s operation is described in a previous paper. However there are still frequency components in the 60-720 Hz sub-harmonic ripple range, modulating the spill structure due to extraction power supplies and any remaining structures on the AGS MMPS. A recent scheme is being developed to use the existing tune-trim control horizontal quadrupole magnets and power supply to further reduce these troublesome noise sources. Feedback from an external beam sensor and overcoming the limitations of the quadrupole system by lead/lag compensation techniques will be described.

Marneris, I.; Danowski, G.; Sandberg, J.; Soukas, A.

1997-07-01

10

Temporal feature extraction in photorefractive resonators  

NASA Astrophysics Data System (ADS)

A holographic optical system listens to an incoming signal and extracts the most common repetitive temporal features of that signal. An example might be to extract the features of Morse code, which consists of two tone lengths and two pause lengths. This optical system is self-organizing, in that very little a priori information is imbeded in the system to indicate what form the temporal signals take. The primary constraints imposed on the signal is: (1) finite bandwidth; (2) limited feature duration; and (3) rates of reoccurrence. The optical apparatus uses a photorefractively pumped multimode optical oscillator having a delay line in the feedback loop. The delay line serves to translate the temporal dimension into a spatial one, and it also builds into the system a notion of the direction of time. Temporal feature extraction takes place as a competitive interaction among sets of modes, which are termed chronomodes. Experiments illustrate the principles of such a system by extracting the two most probable temporal features from a signal imposed on a laser beam.

Anderson, Dana Z.; Zhou, Gan; Montemezzani, Germano

1994-12-01

11

Selective resonant extraction from the Fermilab Main Injector using electron lens  

SciTech Connect

We propose to use an electron lens for slow extraction of proton bunches from the Fermilab Main Injector. Negatively charged electron beam colliding with protons causes positive tune shift proportional to the electron current. If the resulting tune satisfies resonance condition, protons move to larger betatron amplitudes as in conventional slow extraction systems. Time variation of the electron current allows slow extraction from particular batches or even slow extraction from a single bunch.

Vladimir Shiltsev and John Marriner

2001-07-20

12

Characterization of miniaturized metamaterial resonators coupled to planar transmission lines through parameter extraction  

Microsoft Academic Search

In this paper, a method for obtaining the electrical characteristics of metamaterial resonators coupled to planar transmission lines is proposed. This parameter extraction technique is based on the comparison between the measured (or full wave electromagnetic simulated) transmission and reflection characteristics of a host line loaded with such resonators and those obtained from its lumped element equivalent circuit model (previously

F. Aznar; M. Gil; J. Bonache; L. Jelinek; J. D. Baena; R. Marqués; F. Martín

2008-01-01

13

Equivalent circuit parameters of resonant tunneling diodes extracted from self-consistent Wigner-Poisson simulation  

Microsoft Academic Search

The equivalent circuit parameters of resonant tunneling diodes (RTD) are extracted from numerical simulation results for RTDs. The RTD models used in this paper are double barrier structures. The influence of the resonant tunneling structure (RTS) parameters, such as the height of barriers, the width of the quantum well, the width of the spacers, and the width of the barriers,

Peiji Zhao; Hong Liang Cui; Dwight L. Woolard; Kevin L. Jensen; F. A. Buot

2001-01-01

14

Improved ion extraction from an electron cyclotron resonance ion source by a metal-dielectric-extraction electrode  

Microsoft Academic Search

The goal of the experiment was to study the influence and the physics of the boundary region (between the plasma and the extraction potential) with direct impact on the source ion-beam output. A specially processed high-emissive metal-dielectric structure was installed on the extraction electrode of the Frankfurt 14 GHz electron cyclotron resonance ion source (ECRIS), forming a so-called metal-dielectric- (MD)

L. Schachter; S. Dobrescu; K. E. Stiebing

2006-01-01

15

Extraction of Meson Resonances from Three-pions Photo-production Reactions  

SciTech Connect

We have investigated the model dependence of meson resonance properties extracted from the Dalitz-plot analysis of the three-pions photoproduction reactions on the nucleon. Within a unitary model developed in Phys. Rev. D 84, 114019 (2011), we generate Dalitz-plot distributions as data to perform an isobar model fit that is similar to most of the previous analyses of three-pion production reactions. It is found that the resonance positions from the two models agree well when both fit the data accurately, except for the resonance poles near branch points. The residues of the resonant amplitudes extracted from the two models and by the usual Breit-Wigner procedure agree well only for the isolated resonances with narrow widths. For overlapping resonances, most of the extracted residues could be drastically different. Our results suggest that even with high precision data, the resonance extraction should be based on models within which the amplitude parametrization is constrained by three-particle unitarity condition.

S. X. Nakamura, H. Kamano, T.-S. H. Lee, T. Sato

2012-12-01

16

Characterization of phosphorus in sequential extracts from lake sediments using 31 P nuclear magnetic resonance spectroscopy  

Microsoft Academic Search

Phosphorus (P) compounds in three different lake surface sediments were extracted by sequential P extrac- tion and identified by 31P nuclear magnetic resonance (31P NMR) spectroscopy. The extraction procedure primarily discriminates between inorganic P-binding sites but most extraction steps also contained P not reacting (nrP) with the molybdenum complex during P analyses. In all three lakes, the nrP dominated in

Kasper Reitzel; Joakim Ahlgren; Adolf Gogoll; Henning S. Jensen; Emil Rydin

2006-01-01

17

Multichannel parametrization of K¯N scattering amplitudes and extraction of resonance parameters  

NASA Astrophysics Data System (ADS)

We present results of a new multichannel partial-wave analysis for K¯N scattering in the center-of-mass (c.m.) energy range from 1480 to 2100 MeV. Resonance parameters were extracted by fitting partial-wave amplitudes from all considered channels using a multichannel parametrization that is consistent with S-matrix unitarity. The resonance parameters are generally in good agreement with predictions of the Koniuk-Isgur quark model.

Zhang, H.; Tulpan, J.; Shrestha, M.; Manley, D. M.

2013-09-01

18

Extracting Low-Lying Lambda Resonances Using Correlation Matrix Techniques  

SciTech Connect

The lowest-lying negative-parity state of the Lambda is investigated in (2+1)-flavour full-QCD on the PACS-CS configurations made available through the ILDG. We show that a variational analysis using multiple source and sink smearings can extract a state lying lower than that obtained by using a standard fixed smeared source and sink operator alone.

Menadue, Benjamin J.; Kamleh, Waseem; Leinweber, Derek B.; Mahbub, M. S. [Special Research Centre for the Subatomic Structure of Matter, School of Chemistry and Physics, University of Adelaide (Australia)

2011-05-24

19

Brain development: 1 H magnetic resonance spectroscopy of rat brain extracts compared with chromatographic methods  

Microsoft Academic Search

We compared in vitro1H magnetic resonance spectroscopy (MRS) measurements of rat brain extracts (rats: 2–56 days old) with chromatographic measurements and in a further step also with results of in vivo MRS. The following substances can be reliably measured in brain extracts by in vitro MRS: N-acetylaspartate (NAA), total creatine (Cr), phosphorylethanoloamine (PE), taurine (Tau), glutamate (Glu), glutamine (Gln), ?-aminobutyrate

R. Burri; P. Bigler; P. Straehl; S. Posse; J-P Colombo; N. Herschkowitz

1990-01-01

20

Improved ion extraction from an electron cyclotron resonance ion source by a metal-dielectric-extraction electrode  

NASA Astrophysics Data System (ADS)

The goal of the experiment was to study the influence and the physics of the boundary region (between the plasma and the extraction potential) with direct impact on the source ion-beam output. A specially processed high-emissive metal-dielectric structure was installed on the extraction electrode of the Frankfurt 14 GHz electron cyclotron resonance ion source (ECRIS), forming a so-called metal-dielectric- (MD) extraction electrode. The emissive layer of the disk faced the plasma; its inner hole was about the size of the normal extraction hole of the ECRIS. The output of the ECRIS in the presence of the MD electrode was compared with the outputs for the standard configuration (overall stainless-steel plasma chamber) and with the same plasma chamber with the radial wall covered by a highly electron emissive MD liner that raise the plasma electron density and temperature. The charge state distributions of the argon ions extracted from the source show an important increase of the ion beam for the high charge states as compared to the standard situation whereas the low charge states are less reduced than in the case of the presence of a MD liner. Due to the special position of the dielectric layer, the MD electrode introduces a new effect, which is connected to its property of becoming a positively charged surface under electron and ion bombardment. The MD electrode creates a quasiconfinement of the peripheral ions in the extraction, those ions that are normally lost to a conducting extraction electrode.

Schachter, L.; Dobrescu, S.; Stiebing, K. E.

2006-03-01

21

Magnetic resonance imaging of nonaqueous phase liquid during soil vapor extraction in heterogeneous porous media  

Microsoft Academic Search

Soil vapor extraction (SVE) is commonly used to remediate nonaqueous phase liquids (NAPLs) from the vadose zone. This paper aims to determine the effect of grain size heterogeneity on the removal of NAPL in porous media during SVE. Magnetic resonance imaging (MRI) was used to observe and quantify the amount and location of NAPL in flow-through columns filled with silica

Yanjie Chu; Charles J. Werth; Albert J. Valocchi; Hongkyu Yoon; Andrew G. Webb

2004-01-01

22

Extraction of electromagnetic transition form factors for nucleon resonances within a dynamical coupled-channels model  

SciTech Connect

We explain the application of a recently developed analytic continuation method to extract the electromagnetic transition form factors for the nucleon resonances (N*) within a dynamical coupled-channel model of meson-baryon reactions. Illustrative results of the obtained N{sup *{yields}{gamma}}N transition form factors, defined at the resonance pole positions on the complex energy plane, for the well-isolated P{sub 33} and D{sub 13} and the complicated P{sub 11} resonances are presented. A formula was developed to give a unified representation of the effects due to the first two P{sub 11} poles, which are near the {pi}{Delta} threshold, but are on different Riemann sheets. We also find that a simple formula, with its parameters determined in the Laurent expansions of the {pi}N{yields}{pi}N and {gamma}N{yields}{pi}N amplitudes, can reproduce to a very large extent the exact solutions of the considered model at energies near the real parts of the extracted resonance positions. We discuss the important differences between our approach, which is consistent with the earlier formulations of resonances, and the phenomenological approaches using the Breit-Wigner parametrization of resonant amplitudes to fit the data.

Suzuki, N.; Sato, T. [Department of Physics, Osaka University, Toyonaka, Osaka 560-0043 (Japan); Excited Baryon Analysis Center (EBAC), Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States); Lee, T.-S. H. [Excited Baryon Analysis Center (EBAC), Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States); Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

2010-10-15

23

Multiaperture ion beam extraction from gas-dynamic electron cyclotron resonance source of multicharged ions  

SciTech Connect

Electron cyclotron resonance ion source with quasi-gas-dynamic regime of plasma confinement (ReGIS), constructed at the Institute of Applied Physics, Russia, provides opportunities for extracting intense and high-brightness multicharged ion beams. Despite the short plasma lifetime in a magnetic trap of a ReGIS, the degree of multiple ionization may be significantly enhanced by the increase in power and frequency of the applied microwave radiation. The present work is focused on studying the intense beam quality of this source by the pepper-pot method. A single beamlet emittance measured by the pepper-pot method was found to be {approx}70 {pi} mm mrad, and the total extracted beam current obtained at 14 kV extraction voltage was {approx}25 mA. The results of the numerical simulations of ion beam extraction are found to be in good agreement with experimental data.

Sidorov, A.; Dorf, M.; Zorin, V.; Bokhanov, A.; Izotov, I.; Razin, S.; Skalyga, V.; Rossbach, J.; Spaedtke, P.; Balabaev, A. [Institute of Applied Physics, RAS, 46 Ulyanov St., 603950 Nizhny Novgorod (Russian Federation); Gesellschaft fur Schwerionenforschung (GSI), Planckstr. 1, 64291 Darmstadt (Germany); Institute for Theoretical and Experimental Physics, 25 B. Cheremushkinskaya St., 117259 Moscow (Russian Federation)

2008-02-15

24

Resonance extractions in the {alpha}+{sup 8}He slow scattering  

SciTech Connect

The {alpha}+{sup 8}He low-energy reactions and the exotic structures of {sup 12}Be={alpha}+{alpha}+4N are studied by the application of the generalized two-center cluster model. In the two-neutron transfer reactions, {alpha}+{sup 8}He{sub g.s.}{yields}{sup 6}He{sub g.s.}+{sup 6}He{sub g.s.}, resonant structures with a sharp width of {Gamma}<1 MeV appear in the central collision (J{sup {pi}=}0{sup +}). The reaction mechanism is analyzed, and we confirmed that the transfer coupling plays essential roles in the resonance formation with sharp width. Angular distributions for the scattered {sup 6}He are analyzed to extract resonant structures for individual partial waves. We found that, for the low-spin resonances, the angular selection around 90 deg. in the center-of-mass system, which is usually employed in the high-spin resonances of light-ion systems, is not necessarily appropriate to separate the resonance contribution with a definite spin. The validity of the selection angle around 90 deg. is discussed in the higher partial waves.

Ito, Makoto [Pure and Applied Physics, Kansai University, Yamate-cho 3-3-35, Suita 564-8680 (Japan); Research Center for Nuclear Physics (RCNP), Osaka University, Mihogaoka 10-1, Suita 567-0047 (Japan); RIKEN Nishina Center for Accelerator-based Science, RIKEN, Wako, 351-0198, Saitama (Japan); Suzuki, Daisuke [National Superconducting Cyclotron Laboratory, Michigan State University, 1 Cyclotron, East Lansing, Michigan 48824-1321 (United States)

2011-07-15

25

Study on proton fraction of beams extracted from electron cyclotron resonance ion source  

NASA Astrophysics Data System (ADS)

A permanent magnet electron cyclotron resonance ion source PMECR II is used to generate proton ions for radio frequency quadrupole (RFQ) injection at Peking University (PKU). The proton fractions of the extracted beam were measured at the positions both after extraction system of ion source and the end of low energy beam transport line (LEBT). Experiments show that the proton fraction has a rise time within a beam pulse, and its value varies with pulse width and microwave power. The proton fractions measured at different positions are comparable.

Xu, R.; Zhao, J.; Peng, S. X.; Yuan, Z. X.; Song, Z. Z.; Yu, J. X.; Guo, Z. Y.

2008-02-01

26

Extraction of the target isotope on the collector by the ion cyclotron resonance method  

NASA Astrophysics Data System (ADS)

Theoretical issues concerning isotope separation by the ion cyclotron resonance method are considered. A version of the experimental ion cyclotron resonance setup and ways of producing a plasma stream are described. Techniques used to vaporize the working agent and its transport to the ioniation zone are discussed. The separating characteristics of the hot-particle collector at certain parameters of the setup and plasma are calculated. A gadolinium isotope mixture is used as a model. The dependence of the 157Gd target isotope concentration on the separating plate on the longitudinal coordinate reckoned from the front edge of the separator is analyzed for different frequency offsets. The target isotope extraction ratio versus the plate distance of the separator for different values of the offset from the resonance frequency is found.

Potanin, E. P.

2008-04-01

27

Detection of free radicals in aqueous extracts of cigarette tar by electron spin resonance  

Microsoft Academic Search

Aqueous extracts of cigarette tar (ACT) autooxidize to produce semiquinone, hydroxyl, and superoxide radicals in air-saturated buffered aqueous solutions. The semiquinone species were detected by direct electron spin resonance (ESR) measurements and identified as o-and p-benzosemiquinone radicals by comparison with the ESR signals of catechol and hydroquinone radicals under similar conditions. The rate of formation of these radicals was dependent

Lun-Yi Zang; Koni Stone; William A. Pryor

1995-01-01

28

A proposed U.S./China theoretical/experimental collaborative effort on baryon resonance extraction  

SciTech Connect

In this paper we discuss the reasons for our work towards establishing a new collaboration between Jefferson Lab (JLab) and the Institute of High Energy Physics (IHEP) in Beijing. We seek to combine experimentalists and theorists into a dedicated group focused on better understanding the current and future data from JLab and from the Beijing Electron Positron Collider (BEPC). Recent JLab results on the extraction of single- and double-polarization observables in both the 1{pi}- and 2{pi}-channel show their high sensitivity to small production amplitudes and therefore their importance for the extraction of resonance parameters. The Beijing Electron Spectrometer (BES) at the BEPC has collected high statistics data on J/{Psi} production. Its decay into baryon-antibaryon channels offers a unique and complementary way of probing nucleon resonances. The CEBAF Large Acceptance Spectrometer, CLAS, has access to N* form factors at high Q{sup 2}, which is advantageous for the study of dynamical properties of nucleon resonances, while the low-background BES results will be able to provide guidance for the search for less-dominant excited states at JLab. Moreover, with the recently approved experimental proposal Nucleon Resonance Studies with CLAS12 and the high-quality data streaming from BES-III and CLAS, the time has come for forging a new Trans-Pacific collaboration of theorists and experimentalists on NSTAR physics.

P.L. Cole

2009-12-01

29

H- extraction from electron-cyclotron-resonance-driven multicusp volume source operated in pulsed mode  

NASA Astrophysics Data System (ADS)

H2 microwave (2.45 GHz) pulsed plasma is produced from seven elementary electron cyclotron resonance sources installed into the magnetic multipole chamber ``Camembert III'' (École Polytechnique-Palaiseau) from which H- extraction takes place. The negative-ion and electron extracted currents are studied through electrical measurements and the plasma parameters by means of electrostatic probe under various experimental conditions. The role of the plasma electrode bias and the discharge duty cycle in the extraction process is emphasized. The gas breakdown at the beginning of every pulse gives rise to variations of the plasma characteristic parameters in comparison with those established at the later time of the pulse, where the electron temperature, the plasma potential, and the floating potential converge to the values obtained for a continuous plasma. The electron density is significantly enhanced in the pulsed mode.

Svarnas, P.; Bacal, M.; Auvray, P.; Béchu, S.; Pelletier, J.

2006-03-01

30

Light extraction for a doubly resonant cavity organic LED: the RC2LED  

NASA Astrophysics Data System (ADS)

The RC2LED is a substrate emitting OLED which has three additional interference layers between the ITO electrode and the glass substrate. This creates two resonant optical cavities. The RC2LED has 2 resonant optical cavities. The first cavity is also present in regular devices and is formed by metal/organic layers/ITO. The second cavity is formed by 3 additional layers: a high refractive index layer (Nb2O5), a low refractive index layer (SiO2) and a high refractive index layer (Nb2O5). The additional layers introduce a strong wavelength dependent improvement of the extraction efficiency compared to the OLED without the additional layers. Our simulations show an improvement of the extraction efficiency of over 70% over a wavelength range of 75 nm compared to an OLED without the 3 layers. Light extraction is worse compared to the reference OLED for wavelengths outside this wavelength range. the when compared to the OLED. This improvement has been experimentally verified for a green OLED with an emission between 500nm and 650 nm. A numerical study shows a relative improvement of 10% for the luminous power efficiency of a 3 color white OLED with the additional layers. The emitted white corresponds with the light emitted by illuminant A. The WOLED has been composed of a fluorescent blue emitter, green and red phosphorescent emitters.

Vandersteegen, Peter; Mladenovski, Saso; van Elsbergen, Volker; Gartner, Georg; Bienstman, Peter; Neyts, Kristiaan; Baets, Roel

2007-10-01

31

Simulation of the extraction from an electron cyclotron resonance ion source under the influence of space charge  

Microsoft Academic Search

The typical extracted particle density from an ion source of the electron cyclotron resonance (ECR) type has been increased during the last few years by several improvements: stronger magnetic fields, higher radio frequency, biased probes, mixing gas, afterglow mode, and other means. The extraction system remained unchanged in most cases, causing problems in beam quality because of the stronger space

P. Spädtke

2002-01-01

32

Progress towards the development of a realistic electron cyclotron resonance ion source extraction model  

SciTech Connect

In this paper, an ongoing effort to provide a simulation and design tool for electron cyclotron resonance ion source extraction and low energy beam transport is described and benchmarked against experimental results. Utilizing the particle-in-cell code WARP, a set of scripts has been developed: A semiempirical method of generating initial conditions, a 2D-3D hybrid method of plasma extraction and a simple beam transport deck. Measured emittances and beam profiles of uranium and helium beams are shown and the influence of the sextupole part of the plasma confinement field is investigated. The results are compared to simulations carried out using the methods described above. The results show that the simulation model (with some additional refinements) represents highly charged, well-confined ions well, but that the model is less applicable for less confined, singly charged ions.

Winklehner, D.; Leitner, D. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); Benitez, J. Y.; Lyneis, C. M.; Strohmeier, M. M. [Lawrence Berkeley National Laboratory, 1 Cyclotron Rd., Berkeley, California 94720 (United States)

2012-02-15

33

Resonance  

NSDL National Science Digital Library

For advanced undergraduate students: Observe resonance in a collection of driven, damped harmonic oscillators. Vary the driving frequency and amplitude, the damping constant, and the mass and spring constant of each resonator. Notice the long-lived transients when damping is small, and observe the phase change for resonators above and below resonance.

Simulations, Phet I.; Dubson, Michael; Loeblein, Patricia; Olson, Jonathan; Perkins, Kathy; Gratny, Mindy

2011-07-20

34

Investigations on the structure of the extracted ion beam from an electron cyclotron resonance ion source  

SciTech Connect

Using improved beam diagnostic tools, the structure of an ion beam extracted from an electron cyclotron resonance ion source (ECRIS) becomes visible. Especially viewing targets to display the beam profile and pepper pot devices for emittance measurements turned out to be very useful. On the contrary, diagnostic tools integrating over one space coordinate like wire harps for profile measurements or slit-slit devices, respectively slit-grid devices to measure the emittance might be applicable for beam transport investigations in a quadrupole channel, but are not very meaningful for investigations regarding the given ECRIS symmetry. Here we try to reproduce the experimentally found structure on the ion beam by simulation. For the simulation, a certain model has to be used to reproduce the experimental results. The model is also described in this paper.

Spaedtke, P.; Lang, R.; Maeder, J.; Rossbach, J.; Tinschert, K. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Planckstr. 1, 64291 Darmstadt (Germany); Maimone, F. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Planckstr. 1, 64291 Darmstadt (Germany); Universita degli Studi di Catania, D.M.F.C.I, Viale A. Doria 6, 95125 Catania (Italy)

2012-02-15

35

Beam size versus intensity for resonant extracted beam at the Brookhaven AGS  

SciTech Connect

Transverse beam sizes were measured in the AGS prior to the initiation of the third order resonance ({nu}{sub H} = 8 2/3; driven by sextupoles) used for the slow extraction and again in the external beam lines. The measurements were made using the AGS Ionization Profile Monitor (IPM) and an External Profile Monitor (EPM). Both of these monitors use the ionized residual gas to image the beam on arrays of wires that are aligned parallel to the direction of the beam. The effects of space charge on the IPM are significant at the intensities measured, but the EPM measurements are not affected by space charge. Two measurements are reported. First is the intensity dependence of the resonant beam size, and secondly, an indirect measure of the space charge effect on the IPM. A differential comparison of the two monitors in the vertical plane allows unfolding the effect of the space charge on the measurements. These measurements were made over an intensity range between 15 {times} 10{sup 12} and 36 {times} 10{sup 12} protons per AGS pulse.

Brown, K.A.; Thern, R. [Brookhaven National Lab., Upton, NY (United States); Huang, H. [Indiana Univ., (United States)

1995-05-01

36

Third Interger Resonance Slow Extraction Using RFKO at High Space Charge  

SciTech Connect

A proposal to search for direct {mu} {yields} e conversion at Fermilab requires slow, resonant extraction of an intense proton beam. Large space charge forces will present challenges, partly due to the substantial betatron tune spread. The main challenges will be maintaining a uniform spill profile and moderate losses at the septum. We propose to use 'radio frequency knockout' (RFKO) for fine tuning the extraction. Strategies for the use of the RFKO method will be discussed here in the context of the Mu2e experiment. The feasibility of this method has been demonstrated in simulations. Tracking simulations show that optimal RFKO frequency modulation in case of the SC beam tune spread is substantially different from that of chromatic tune spread. FM should be centred at the bare betatron frequency rather than in the middle of the tune spread, and additional chromaticity must be added in order to facilitate rapid dilution of the dipole oscillations. Heating efficiency slowly decreases with the SC growing. Colored noise modulation (random signal within a given bandwidth) appears to be the most effective way of modulation, however its advantage over linear modulation is not very large, so practical reasons may prevail in the final choice between the two.

Nagaslaev, V.; Amundson, J.; Johnstone, J.; Park, C.S.; Werkema, S.; /Fermilab

2011-09-15

37

Exploiting jump-resonance hysteresis in silicon auditory front-ends for extracting speaker discriminative formant trajectories.  

PubMed

Jump-resonance is a phenomenon observed in non-linear circuits where the amplitude of the output signal exhibits an abrupt jump when the frequency of the input signal is varied. For [Formula: see text] filters used in the design of analog auditory front-ends (AFEs), jump-resonance is generally considered to be undesirable and several techniques have been proposed in literature to avoid or alleviate this artifact. In this paper we explore the use of jump-resonance based hysteresis in [Formula: see text] band-pass filters for encoding speech formant trajectories. Using prototypes of silicon AFEs fabricated in a 0.5 ?m CMOS process, we demonstrate the benefits of the proposed approach for extracting speaker discriminative features. These benefits are validated using speaker recognition experiments where consistent improvements in equal-error-rates (EERs) are achieved using the jump-resonance based features as compared to conventional features. PMID:23893199

Aono, Kenji; Shaga, Ravi K; Chakrabartty, Shantanu

2013-08-01

38

Resonance  

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, Resonance, is the sixth chapter in the Volume II textbook. Topics covered in this chapter include: electric pendulum, simple parallel resonance, simple series resonance, resonance in series-parallel circuits, and Q and bandwidth of a resonant circuit. 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

39

Extracting S-matrix poles for resonances from numerical scattering data: Type-II Padé reconstruction  

NASA Astrophysics Data System (ADS)

We present a FORTRAN 77 code for evaluation of resonance pole positions and residues of a numerical scattering matrix element in the complex energy (CE) as well as in the complex angular momentum (CAM) planes. Analytical continuation of the S-matrix element is performed by constructing a type-II Padé approximant from given physical values (Bessis et al. (1994) [42]; Vrinceanu et al. (2000) [24]; Sokolovski and Msezane (2004) [23]). The algorithm involves iterative ‘preconditioning’ of the numerical data by extracting its rapidly oscillating potential phase component. The code has the capability of adding non-analytical noise to the numerical data in order to select ‘true’ physical poles, investigate their stability and evaluate the accuracy of the reconstruction. It has an option of employing multiple-precision (MPFUN) package (Bailey (1993) [45]) developed by D.H. Bailey wherever double precision calculations fail due to a large number of input partial waves (energies) involved. The code has been successfully tested on several models, as well as the F + H2 ? HF + H, F + HD ? HF + D, Cl + HCl ? ClH + Cl and H + D2 ? HD + D reactions. Some detailed examples are given in the text.

Sokolovski, D.; Akhmatskaya, E.; Sen, S. K.

2011-02-01

40

Detection of trinitrotoluene (TNT) extracted from soil using a surface plasmon resonance (SPR)-based sensor platform  

NASA Astrophysics Data System (ADS)

An antibody-based competition assay has been developed using a surface plasmon resonance (SPR) sensor platform for the detection of trinitrotoluene (TNT) in soil extract solutions. The objective of this work is to develop a sensor-based assay technology to use in the field for real- time detection of land mines. This immunoassay combines very simple bio-film attachment procedures and a low-cost SPR sensor design to detect TNT in soil extracts. The active bio-surface is a coating of bovine serum albumin that has been decorated with trinitrobenzene groups. A blind study on extracts from a large soil matrix was recently performed and result from this study will be presented. Potential interferant studied included 2,4-dinitrophenol, 2,4- dinitrotoluene, ammonium nitrate, and 2,4- dichlorophenoxyacetic acid. Cross-reactivity with dinitrotoluene will be discussed. Also, plans to reach sensitivity levels of 1ppb TNT in soil will be described.

Strong, Anita A.; Stimpson, Donald I.; Bartholomew, Dwight U.; Jenkins, Thomas F.; Elkind, Jerome L.

1999-08-01

41

H{sup -} extraction from electron-cyclotron-resonance-driven multicusp volume source operated in pulsed mode  

SciTech Connect

H{sub 2} microwave (2.45 GHz) pulsed plasma is produced from seven elementary electron cyclotron resonance sources installed into the magnetic multipole chamber 'Camembert III' (Ecole Polytechnique-Palaiseau) from which H{sup -} extraction takes place. The negative-ion and electron extracted currents are studied through electrical measurements and the plasma parameters by means of electrostatic probe under various experimental conditions. The role of the plasma electrode bias and the discharge duty cycle in the extraction process is emphasized. The gas breakdown at the beginning of every pulse gives rise to variations of the plasma characteristic parameters in comparison with those established at the later time of the pulse, where the electron temperature, the plasma potential, and the floating potential converge to the values obtained for a continuous plasma. The electron density is significantly enhanced in the pulsed mode.

Svarnas, P.; Bacal, M.; Auvray, P.; Bechu, S.; Pelletier, J. [LPTP, Ecole Polytechnique, UMR 7648 du CNRS, 91128 Palaiseau (France); Centre de Recherche Plasmas-Materiaux-Nanostructures, LPSC, 53 rue des Martyrs, 38026 Grenoble Cedex (France)

2006-03-15

42

A novel technique for the pre-concentration and extraction of inositol hexakisphosphate from soil extracts with determination by phosphorus-31 nuclear magnetic resonance.  

PubMed

Inositol hexakisphosphate (IP6) is often the dominant form of soil organic phosphorus (P), but is rarely investigated because of the analytical difficulties encountered in its extraction, separation, and detection in environmental samples. In particular, recent advances in the study of soil organic P with 31P nuclear magnetic resonance (NMR) have been of limited use for the study of IP6, because the technique does not discriminate between IP6 and other forms of P. This was addressed by developing a novel analytical procedure using the retentive properties of gel-filtration gels for IP6, which allows the combined selective extraction and pre-concentration of IP6 from soil extracts with determination by 31P NMR. While the technique is still in the developmental stage, the results demonstrate that the gel does not interfere with 31P NMR analysis and retains IP6 to concentrations well above those required to give clear spectral signals. The technique has considerable potential for application to the study of IP6 in soil extracts and water samples and, with development, could help to answer fundamental questions regarding the dynamics of organic P in the environment. PMID:11931435

Turner, Benjamin L; McKelvie, Ian D

43

Following plant metabolism in vivo and in extracts with heteronuclear two-dimensional nuclear magnetic resonance spectroscopy.  

PubMed

Limits of sensitivity and spectral resolution currently restrict the application of nuclear magnetic resonance (NMR) spectroscopy in plant metabolism. This study shows that these limits can be substantially expanded through the application of heteronuclear single- and multiple-quantum two-dimensional (2D) spectroscopic methods using pulsed field gradients both in vivo and in extracts. The course of metabolism in approximately 0.2 g of maize (Zea mays L.) root tips labeled with [1-13C]glucose was followed with 1 min time resolution using heteronuclear multiple quantum coherence (HMQC) 13C-1H spectroscopy in vivo. The timing of alanine, lactate, and ethanol synthesis was followed during the transition from normal to hypoxic conditions. In extracts of labeled maize root tips, 13C-1H heteronuclear single quantum coherence and heteronuclear multiple quantum coherence (HMBC) spectra acquired in 2-3 h allowed the detection and assignment of resonance that are not seen in one-dimensional (1D) 13C NMR spectra of the same samples taken in 12 h. In root tips labeled with 15NH4+, 15N-(1)H HMQC spectra in vivo showed labeling in the amide of glutamine. In extracts, 15N labeling in amines and amides was detected using 15N-1H HMBC spectra that is not seen in 1D 15N spectra of the same sample. PMID:8954532

Shachar-Hill, Y; Pfeffer, P E; Germann, M W

1996-12-01

44

Power penalty measurement and frequency chirp extraction in silicon microdisk resonator modulators.  

SciTech Connect

We demonstrate 5 Gbs and 10 Gbs error free operation of silicon photonic microdisk resonant modulators to a distance of 70 km, measure dispersion power penalties and compare the experimental results with theoretically derived values.

Lentine, Anthony L.; Zortman, William A.; Trotter, Douglas Chandler; Watts, Michael R.

2010-03-01

45

Model-Independent Extraction of the Pole and Breit-Wigner Resonance Parameters  

NASA Astrophysics Data System (ADS)

We show that a slightly modified Breit-Wigner formula can successfully describe the total cross section even for the broad resonances, from the light ?(770) to the heavy Z boson. In addition to the mass, width, and branching fraction, we include another resonance parameter that turns out to be directly related to the pole residue phase. The new formula has two mathematically equivalent forms: one with the pole and the other with the Breit-Wigner parameters.

Ceci, S.; Korolija, M.; Zauner, B.

2013-09-01

46

Simulation of the extraction from an electron cyclotron resonance ion source under the influence of space charge  

NASA Astrophysics Data System (ADS)

The typical extracted particle density from an ion source of the electron cyclotron resonance (ECR) type has been increased during the last few years by several improvements: stronger magnetic fields, higher radio frequency, biased probes, mixing gas, afterglow mode, and other means. The extraction system remained unchanged in most cases, causing problems in beam quality because of the stronger space charge. Simulation of the extraction is helpful in understanding the physics, but a correct simulation requires a three-dimensional model. Whereas the geometry and the solenoidal component of the magnetic field is cylinder symmetric, the hexapole field determines indirectly the spatial distribution of the ions by Coulomb interaction between electrons and ions. The area where ions are started for the simulation depends therefore on the hexapole field strength. If higher energy electrons within the plasma are present, they should be included to describe the actual plasma boundary more precise. The measured charge state distribution should be used to define the real composition of the plasma. Using all these ingredients, an accel-decel extraction system has been investigated which should be able to handle higher ion currents as were available from ECR sources so far. It could be shown that the emittance of the extracted beam strongly depends on a good matching of the particle density within the plasma to the extraction field strength. Any nonlinearity of the fields causes emittance growth. Such a nonlinearity is produced by an azimuthal change in the location of the plasma boundary. Therefore, it would be highly desirable to decrease the hexapole field close to the plasma side of the extraction system. A much better beam quality would be achievable.

Spädtke, P.

2002-02-01

47

Spatially resolved charge-state and current-density distributions at the extraction of an electron cyclotron resonance ion source  

SciTech Connect

In this paper we present our measurements of charge-state and current-density distributions performed in very close vicinity (15 mm) of the extraction of our hexapole geometry electron cyclotron resonance ion source. We achieved a relatively high spatial resolution reducing the aperture of our 3D-movable extraction (puller) electrode to a diameter of only 0.5 mm. Thus, we are able to limit the source of the extracted ion beam to a very small region of the plasma electrode's hole (O = 4 mm) and therefore to a very small region of the neutral plasma sheath. The information about the charge-state distribution and the current density in the plane of the plasma electrode at each particular position is conserved in the ion beam. We determined the total current density distribution at a fixed coaxial distance of only 15 mm to the plasma electrode by remotely moving the small-aperture puller electrode which contained a dedicated Faraday cup (FC) across the aperture of the plasma electrode. In a second measurement we removed the FC and recorded m/q-spectra for the different positions using a sector magnet. From our results we can deduce that different ion charge-states can be grouped into bloated triangles of different sizes and same orientation at the extraction with the current density peaking at centre. This confirms observations from other groups based on simulations and emittance measurements. We present our measurements in detail and discuss possible systematic errors.

Panitzsch, Lauri; Peleikis, Thies; Stalder, Michael; Wimmer-Schweingruber, Robert F. [Institute for Experimental and Applied Physics (IEAP), Christian-Albrechts-Universitaet, Kiel (Germany)

2011-09-15

48

Oral magnetic resonance imaging contrast agent based on Ilex paraguayensis herbal extract.  

PubMed

In this article we demonstrate the potential of herbal extracts from yerba mate (Ilex paraguayensis) as an oral contrast agent for MRI. At typical drinking concentrations, yerba mate acts as a "biphasic" contrast agent with T1 weighting at short echo times and T2 weighting at echo times greater than about 40 ms. Based on data obtained from X-ray fluorescence elemental analysis, NMR relaxometry, and ESR we identify the relaxation agent in the extract as a low-molecular-weight manganese complex. Yerba mate exhibits an unusually high manganese content that is readily available for hot water extraction. Despite the high elemental manganese levels in I. paraguayensis extract, no manganese-related toxicity of yerba mate has been observed even among heavy yerba mate drinkers, indicating that the manganese in the extract has only a very low bioavailability. Imaging results on staff and patient volunteers demonstrate good contrasting of the GI tract. The relaxation studies of the contrast agent show a sensitivity to pH that is consistent with imaging results from stomach and small bowel. PMID:16538607

Nestle, Nikolaus; Pauls, Sandra; Wunderlich, Arthur

2006-04-01

49

Automatic segmentation of the bone and extraction of the bone-cartilage interface from magnetic resonance images of the knee.  

PubMed

The accurate segmentation of the articular cartilages from magnetic resonance (MR) images of the knee is important for clinical studies and drug trials into conditions like osteoarthritis. Currently, segmentations are obtained using time-consuming manual or semi-automatic algorithms which have high inter- and intra-observer variabilities. This paper presents an important step towards obtaining automatic and accurate segmentations of the cartilages, namely an approach to automatically segment the bones and extract the bone-cartilage interfaces (BCI) in the knee. The segmentation is performed using three-dimensional active shape models, which are initialized using an affine registration to an atlas. The BCI are then extracted using image information and prior knowledge about the likelihood of each point belonging to the interface. The accuracy and robustness of the approach was experimentally validated using an MR database of fat suppressed spoiled gradient recall images. The (femur, tibia, patella) bone segmentation had a median Dice similarity coefficient of (0.96, 0.96, 0.89) and an average point-to-surface error of 0.16 mm on the BCI. The extracted BCI had a median surface overlap of 0.94 with the real interface, demonstrating its usefulness for subsequent cartilage segmentation or quantitative analysis. PMID:17327652

Fripp, Jurgen; Crozier, Stuart; Warfield, Simon K; Ourselin, Sébastien

2007-02-27

50

Resolution of the multichannel anomaly in the extraction of S-matrix resonance-pole parameters  

SciTech Connect

Within the framework of a mathematically well-defined coupled-channel T-matrix model we have improved the existing multichannel pole-extraction procedure based on the numerical analytic continuation of the channel propagator, and for the first time we present the full set of pole parameters for already published amplitudes. Standard single-channel pole-extraction method (speed plot) was then applied to those amplitudes and resulting sets of T-matrix poles were inspected. The anomaly has been established that in some partial waves the pole values extracted using the standard single-channel methods differ not only from the values obtained using the analytic continuation method, but also change from one reaction to another. Inspired by this peculiarity, we have developed a new single-channel pole-extraction method based solely on the assumption of the partial wave analyticity. Since the speed plot turns out to be the lowest order term of the proposed method, the anomaly is understood and resolved.

Ceci, Sasa [Rudjer Boskovic Institute, Bijenicka cesta 54, P.O. Box 180, 10002 Zagreb (Croatia); Department of Physics and Astronomy, University of Georgia, Athens, GA 30602 (United States); Stahov, Jugoslav [Abilene Christian University, ACU Station Box 27963, Abilene, TX 79699 (United States); University of Tuzla, Faculty of Science, Univerzitetska 4, 35000 Tuzla (Bosnia and Herzegowina); Svarc, Alfred; Zauner, Branimir [Rudjer Boskovic Institute, Bijenicka cesta 54, P.O. Box 180, 10002 Zagreb (Croatia); Watson, Shon [Abilene Christian University, ACU Station Box 27963, Abilene, TX 79699 (United States)

2008-06-01

51

Techniques for Extracting the Complex Resonances of a System Directly from Its Transient Response.  

National Technical Information Service (NTIS)

An approach for extracting the singularities of a system from its transient response to a given excitation is discussed. The method developed is based on Prony's algorithm. Some basic problems which are associated with the use of Prony's algorithm are dis...

M. L. Van Blaricum R. Mittra

1977-01-01

52

Results of Nucleon Resonance Extraction via Dynamical Coupled-Channels Analysis from #11;Collaboration @ EBAC  

SciTech Connect

We review a global analysis of meson production reactions off the nucleons by a collaboration at Excited Baryon Analysis Center of Jefferson Lab. The analysis is pursued with a dynamical coupled-channels approach, within which the dynamics of multi-channel reaction processes are taken into account in a fully consistent way with the two-body as well as three-body unitarity of the S-matrix. With this approach, new features of nucleon excitations are revealed as resonant particles originating from the non-trivial multi-channel reaction dynamics, which cannot be addressed by static hadron models where the nucleon excitations are treated as stable particles.

Hiroyuki Kamano

2012-04-01

53

Studies of emittance of multiply charged ions extracted from high temperature superconducting electron cyclotron resonance ion source, PKDELIS  

SciTech Connect

For the high current injector project at Inter University Accelerator Centre, a high temperature superconducting electron cyclotron resonance (ECR) ion source, PKDELIS, would provide the high charge state ions. The emittance of the ECR ion source is an important parameter to design further beam transport system and to match the acceptances of the downstream radio frequency quadrupole and drift tube linac accelerators of the high current injector. The emittance of the analyzed beam of PKDELIS ECR source has been measured utilizing the three beam size technique. A slit and two beam profile monitors positioned at fixed distances from each other were used to measure the beam size. The digitized beam profiles have been analyzed to determine the emittance of various multiply charged ions. The variation of emittance with gas mixing, ultrahigh frequency power, and extraction energy are discussed in this presentation.

Rodrigues, G.; Lakshmy, P. S.; Kumar, Sarvesh; Mandal, A.; Kanjilal, D.; Roy, A. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Baskaran, R. [Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamilnadu 603102 (India)

2010-02-15

54

A femtogram resolution mass sensor platform, based on SOI electrostatically driven resonant cantilever. Part I: electromechanical model and parameter extraction.  

PubMed

A microcantilever based platform for mass detection in the femtogram range has been integrated in the doped top silicon layer of a SOI substrate. The on-plane fundamental resonance mode of the cantilever is excited electrostatically and detected capacitively by means of two parallel placed electrodes in a two port configuration. An electromechanical model of the cantilever-electrodes transducer and its implementation in a SPICE environment are presented. The model takes into account non-linearities from variable cantilever-electrode gap, fringing field contributions and real deflection shape of the cantilever for the calculation of the driving electrostatic force. A fitting of the model to the measured S(21) transmitted power frequency response is performed to extract the characteristic sensor parameters as Young modulus, Q factor, electrical parasitics and mass responsivity. PMID:16675119

Teva, J; Abadal, G; Torres, F; Verd, J; Pérez-Murano, F; Barniol, N

2006-04-18

55

Influence of frequency tuning and double-frequency heating on ions extracted from an electron cyclotron resonance ion source  

SciTech Connect

The electromagnetic field within the plasma chamber of an electron cyclotron resonance ion source (ECRIS) and the properties of the plasma waves affect the plasma properties and ion beam production. We have experimentally investigated the ''frequency tuning effect'' and ''double frequency heating'' on the CAPRICE ECRIS device. A traveling wave tube amplifier, two microwave sweep generators, and a dedicated experimental set-up were used to carry out experiments in the 12.5-16.5 GHz frequency range. During the frequency sweeps the evolution of the intensity and shape of the extracted argon beam were measured together with the microwave reflection coefficient. A range of different ion source parameter settings was used. Here we describe these experiments and the resultant improved understanding of these operational modes of the ECR ion source.

Maimone, F. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Planckstr. 1, 64291 Darmstadt (Germany); Universita degli Studi di Catania, D.M.F.C.I,Viale A. Doria 6, 95125 Catania (Italy); Celona, L. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); Lang, R.; Maeder, J.; Rossbach, J.; Spaedtke, P.; Tinschert, K. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Planckstr. 1, 64291 Darmstadt (Germany)

2011-12-15

56

Automatic extraction of the midsagittal plane from volumetric magnetic resonance images  

NASA Astrophysics Data System (ADS)

A novel method is presented to automatically extract the midsagittal plane (MSP) from volumetric MR images. The MSP which generally approximates the interhemispheric fissure is the plane separating both hemispheres. It is meaningful for the brain segmentation, registration, quantification and pathology detection especially in Talairach space. The algorithm works based on the theory of the symmetry principal axis, the local searching method and minimizing the local symmetry coefficient. The proposed algorithm is validated on 20 T2-weighted MR data sets, which indicates that a clear MSP image can be extracted in the presence of relatively bigger distance error or angular deviation. This fully automatic algorithm is potentially useful in the clinical application and for research.

Fu, Yili; Zhang, Guangcai; Wang, Shuguo; Gao, Wenpeng; Liu, Hao

2009-10-01

57

Lateral resonant Doppler imaging for quantitative flow extraction in spectral domain optical coherence tomography  

NASA Astrophysics Data System (ADS)

In spectral domain Doppler OCT, any transverse motion component of the obliquely moving sample relative to the incident sample beam causes a damping of the correlation between subsequent backscattering signals or even the loss of it making a phase-resolved Doppler flow analysis difficult because of the strong mean error of the Doppler phase shift. To circumvent this effect, a new method for resonant Doppler flow imaging and quantification in spectral domain OCT is proposed where the scanner movement velocity is approximately matched to the transverse velocity component of the oblique sample motion similar to a tracking shot where the camera is moved with respect to the sample. As a result, the backscattering signals corresponding to the moving sample will be highly correlated whereas those of static sample structures and slowly moving scatterers will be less correlated and damped depending on the scanner velocity. Advantageously, for the exact flow velocity quantification the new Doppler relationship of phase shift and sample velocity has not to be applied and the linear relation of the classic Doppler model can still be used. In the present work, first results of the lateral resonant Doppler imaging are shown for an 1 percent Intralipid flow phantom study.

Walther, Julia; Cimalla, Peter; Koch, Edmund

2011-02-01

58

Extracting protein folding kinetics in single-pair fluorescence resonance energy transfer experiment based on wavelet analysis  

NASA Astrophysics Data System (ADS)

Dynamic structural changes of protein folding and biological macromolecules undergoing biochemical reactions can be monitored and studied using the single-pair fluorescence resonance energy transfer (sp-FRET) spectroscopy tool. In this work, we have simulated a single-pair FRET photoemission process as an illustrative model example, where a FRET pair resides on a folding protein that undergoes diffusion in water. And then we apply the wavelet analysis method, which is a widely used method in many fields, such as the digital signal processing, noise reduction and the data compression (JPEG2000), to deal with the case of fluorescence resonance energy transfer (FRET) experiment for protein folding. It is shown that the wavelet analysis filter facilitates the detection of various intermediate conformational states in a noisy trajectory. Thus it is finally suggested that it is particularly suitable for sp-FRET spectroscopy studies of protein folding and can be of use for directly extracting the folding energy landscape. Our study establishes potentially useful data analysis technique and theoretical guidelines for the study of sp-FRET spectroscopy experiments.

Shan, Guangcun; Huang, Wei

2007-01-01

59

Chemical identification strategies using liquid chromatography-photodiode array-solid-phase extraction-nuclear magnetic resonance/mass spectrometry.  

PubMed

The identification of metabolites in biochemical studies is a major bottleneck in the proliferating field of metabolomics. In particular in plant metabolomics, given the diversity and abundance of endogenous secondary metabolites in plants, the identification of these is not only challenging but also essential to understanding their biological role in the plant, and their value to quality and nutritional attributes as food crops. With the new generation of analytical technologies, in which liquid chromatography (LC)-mass spectrometry (MS) and nuclear magnetic resonance (NMR) play a pioneering role, profiling metabolites in complex extracts is feasible at high throughput. However, the identification of key metabolites remains a limitation given the analytical effort necessary for traditional structural elucidation strategies. The hyphenation of LC-solid phase extraction (SPE)-NMR is a powerful analytical platform for isolating and concentrating metabolites for unequivocal identification by NMR measurements. The combination with LC-MS is a relatively straightforward approach to obtaining all necessary information for structural elucidation. Using this set-up, we could, as an example, readily identify five related glycosylated phenolic acids present in broccoli (Brassica oleracea, group Italica, cv Monaco): 1,2-di-O-E-sinapoyl-?-gentiobiose, 1-O-E-sinapoyl-2-O-E-feruloyl-?-gentiobiose, 1,2-di-O-E-feruloyl-?-gentiobiose, 1,2,2'-tri-O-E-sinapoyl-?-gentiobiose, and 1,2'-di-O-E-sinapoyl-2-O-E-feruloyl-?-gentiobiose. PMID:22351183

Moco, Sofia; Vervoort, Jacques

2012-01-01

60

Preliminary results of the ion extraction simulations applied to the MONO1000 and SUPERSHyPIE electron cyclotron resonance ion sources  

SciTech Connect

The goal of this article is to present simulations on the extraction from an electron cyclotron resonance ion source (ECRIS). The aim of this work is to find out an extraction system, which allows one to reduce the emittances and to increase the current of the extracted ion beam at the focal point of the analyzing dipole. But first, we should locate the correct software which is able to reproduce the specific physics of an ion beam. To perform the simulations, the following softwares have been tested: SIMION 3D, AXCEL, CPO 3D, and especially, for the magnetic field calculation, MATHEMATICA coupled with the RADIA module. Emittance calculations have been done with two types of ECRIS: one with a hexapole and one without a hexapole, and the difference will be discussed.

Pierret, C.; Maunoury, L.; Biri, S.; Pacquet, J. Y.; Tuske, O.; Delferriere, O. [CIRIL, avenue Henri Becquerel, BP 5133, F-14070 Caen cedex 05 (France); ATOMKI, Bem ter 18/c, H-4026 Debrecen (Hungary); GANIL, Bd H. Becquerel BP 55027, F-14076 Caen cedex 05 (France); CEA/Saclay, DSM/DAPNIA, 91191 Gif/Yvette (France)

2008-02-15

61

New opportunities of the application of natural herb and spice extracts in plant oils: application of electron paramagnetic resonance in examining the oxidative stability.  

PubMed

The aim of this study was to establish the applicability of natural water-ethanol extracts of herbs and spices in increasing the oxidative stability of plant oils and in the production of novel food. Different concentrations (0, 100, 300, 500, and 700 ppm) of spice extracts and butylated hydroxyanisole (BHA) (100 ppm) were added to the studied oils. The antioxidant activity of spice extracts was determined with electron paramagnetic resonance (EPR) spectroscopy using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical assay. The study showed that the extracts significantly increased the oxidative stability of the examined oils when compared to one of the strongest synthetic antioxidants--BHA. The applied simple production technology and addition of herb and spice extracts to plant oils enabled enhancement of their oxidative stability. The extracts are an alternative to the oils aromatized with an addition of fresh herbs, spices, and vegetables because it did not generate additional flavors thus enabling the maintenance of the characteristic ones. Moreover, it will increase the intake of natural substances in human diet, which are known to possess anticarcinogenic properties. PMID:22900972

Koz?owska, Mariola; Szterk, Arkadiusz; Zawada, Katarzyna; Z?bkowski, Tomasz

2012-08-17

62

Direct assessment by electron spin resonance spectroscopy of the antioxidant effects of French maritime pine bark extract in the maxillofacial region of hairless mice  

PubMed Central

Flavangenol, one of extract of French maritime pine bark, is a complex mixture of bioflavonoids with oligometric proanthocyanidins as the major constituents. These constituents, catechin and procyanidin B1, are water-soluble derivatives of flavangenol. In this study, we investigated the antioxidant effects of flavangenol on reactive oxygen species such as hydroxyl radical, superoxide anion and singlet oxygen using electron spin resonance and spin trapping. The effect of flavangenol on oxidative stress in the skin from the maxillofacial region of hairless mice was investigated using an in vivo L-band electron spin resonance imaging system. Flavangenol attenuated oxidative stress in the maxillofacial skin by acting as a reactive oxygen species scavenger, as demonstrated by in vitro and in vivo electron spin resonance imaging analysis. The absorption and metabolism of flavangenol were also examined. After oral administration of flavangenol in human and rat, most of the catechin in plasma was in the conjugated form, while 45% to 78% of procyanidin B1 was unconjugated, indicating that non-conjugated procyanidin B1 would be active in the circulation. The ability of flavangenol to reduce reactive oxygen species levels in the circulation of the maxillofacial region suggests that this extract may be beneficial for skin protection from exposure to ultraviolet irradiation.

Yoshida, Ayaka; Yoshino, Fumihiko; Tsubata, Masahito; Ikeguchi, Motoya; Nakamura, Takeshi; Lee, Masaichi-Chang-il

2011-01-01

63

Design and Measurement of a Digital Phase Locked BWO for Accurately Extracting the Quality Factors in a Biconcave Resonator System  

NASA Astrophysics Data System (ADS)

A long loop phase locked backward-wave oscillator (BWO) for a high quality factor resonator system operating at D-band frequencies (130-170GHz) was described, the phase noise of the phased locked BWO was analyzed and measured at typical frequencies. When it used with a high quality factor open resonator for measuring the quality factor of simple harmonic resonators based on the magnitude transfer characteristic, this system has proven to be capable of accurate measuring the quality factor as high as 0.8 million with an uncertainty of less than 1.3% (Lorentzian fitting) at typical frequencies in the range of 130GHz-170GHz.

Gao, Yuanci; Charles, Jones R.; Yu, Guofen; Jyotsna, Dutta M.

2012-03-01

64

Polycrystalline silicon-carbide surface-micromachined vertical resonators-part II: electrical testing and material property extraction  

Microsoft Academic Search

This manuscript is the second of a two part series describing the fabrication and testing of megahertz frequency, polycrystalline silicon-carbide (poly-SiC) micromechanical resonators made from films deposited by atmospheric pressure chemical vapor deposition. In Part I, the development of deposition and patterning techniques suitable for the fabrication of vertically actuated, clamped-clamped beam resonant structures was detailed (see Wiser, Chung, Mehregan,

Robert F. Wiser; Massood Tabib-Azar; Mehran Mehregany; Christian A. Zorman

2005-01-01

65

Metabonomic analysis of water extracts from Chinese and American ginsengs by 1H nuclear magnetic resonance: identification of chemical profile for quality control  

PubMed Central

Background With the gaining popularity of commercially prepared decoctions of herbal medicines on the market, an objective and efficient way to reveal the authenticity of such products is urgently needed. Previous attempts to use chromatographic or spectroscopic methods to identify ginseng samples made use of components derived from methanol extracts of the herb. It was not established that these herbs can be distinguished solely from consumable components, which are responsible for the clinical efficacy of the herb. In this study, metabonomics, or metabolic profiling, based on the application of 1H-Nuclear Magnetic Resonance (NMR), is applied to distinguish the water extracts of three closely related ginseng species: P. ginseng (from two different cultivated regions in China), P. notoginseng and P. quinquefolius. Methods A water extraction protocol that mimics how ginseng decoctions are made for consumption was used to prepare triplicate samples from each herb for analysis. High-resolution 1H NMR spectroscopy was used to acquire metabolic profiles of the four ginseng samples. The spectral data were subjected to multivariate and univariate analysis to identify metabolites that were able to distinguish different types of ginseng. Results H NMR metabolic profiling was performed to distinguish the water extracts of P. ginseng cultivated in Hebei and Jilin of China, both of which were distinguished from extracts of P. notoginseng and P. quinquefolius, by unsupervised principle component analysis based on the entire 1H NMR spectral fingerprint Statistically significant differences were found for several discriminating features traced to common metabolites and the ginsenosides Rg1 and Rd, in the 1H NMR spectra. Conclusion This study demonstrated that 1H NMR metabonomics can simultaneously distinguish different ginseng species and multiple samples of the same species that were cultivated in different regions. This technique is applicable to the authentication and quality control of ginseng products.

2012-01-01

66

A Semi-automatic Image Segmentation Method for Extraction of Brain Volume from In Vivo Mouse Head Magnetic Resonance Imaging using Constraint Level Sets  

PubMed Central

In vivo magnetic resonance imaging (MRI) of mouse brain has been widely used to non-invasively monitor disease progression and/or therapeutic effects in murine models of human neurodegenerative disease. Segmentation of MRI to differentiate brain from non-brain tissue (usually referred to as brain extraction) is required for many MRI data processing and analysis methods, including coregistration, statistical parametric analysis, mapping to brain atlas and histology. This paper presents a semi-automatic brain extraction technique based on a level set method with the incorporation of user-defined constraints. The constraints are derived from the prior knowledge of brain anatomy by defining brain boundary on orthogonal planes of the MRI. Constraints are incorporated in the level set method by spatially varying the weighting factors of the internal and external forces and modifying the image gradient (edge) map. Both two-dimensional multi-slice and three-dimensional versions of the brain extraction technique were developed and applied to MRI data with minimal brain/non-brain contrast T1-weighted (T1-wt) FLASH and maximized contrast T2-weighted (T2-wt) RARE. Results were evaluated by calculating the overlap measure (OM) between the automatically segmented and manually traced brain volumes. Results demonstrate that this technique accurately extracts the brain volume (mean OM = 94 %) and consistently outperformed the region growing method applied to the T2-wt RARE MRI (mean OM = 81 %). This method not only successfully extracts the mouse brain in low and high contrast MRI, but can also be used to segment other organs and tissues.

Uberti, Mariano G.; Boska, Michael D.; Liu, Yutong

2009-01-01

67

Automatic segmentation of the bone and extraction of the bone cartilage interface from magnetic resonance images of the knee  

Microsoft Academic Search

The accurate segmentation of the articular cartilages from magnetic resonance (MR) images of the knee is important for clinical studies and drug trials into conditions like osteoarthritis. Currently, segmentations are obtained using time-consuming manual or semi-automatic algorithms which have high inter- and intra-observer variabilities. This paper presents an important step towards obtaining automatic and accurate segmentations of the cartilages, namely

Jurgen Fripp; Stuart Crozier; Simon K. Warfield; Sébastien Ourselin

2007-01-01

68

The influence of the extraction voltage on the energetic electron population of an electron cyclotron resonance ion source plasma  

SciTech Connect

An influence of the extraction voltage on the high energy slope of bremsstrahlung radiation spectra has been reported in ECRIS experiments, which is not well understood so far. In order to provide more detailed data on this effect, we have measured bremsstrahlung radiation spectra accompanying especially the evolution of highly charge ions (i.e., by monitoring the Ar{sup 14+} charge state) as the extraction voltage is changed from 0 to 20 kV, in dedicated experiments at the Frankfurt 14 GHz-ECRIS.

Stiebing, K. E. [Institut fuer Kernphysik der J. W. Goethe-Universitaet, Frankfurt/Main (Germany); Schaechter, L.; Dobrescu, S. [National Institute for Physics and Nuclear Engineering, Bucharest (Romania)

2012-02-15

69

Simultaneous molecular formula determinations of natural compounds in a plant extract using 15 T Fourier transform ion cyclotron resonance mass spectrometry  

PubMed Central

Background Plant extracts are a reservoir of pharmacologically active substances; however, conventional analytical methods can analyze only a small portion of an extract. Here, we report a high-throughput analytical method capable of determining most phytochemicals in a plant extract and of providing their molecular formulae from a single experiment using ultra-high-resolution electrospray ionization mass spectrometry (UHR ESI MS). UHR mass profiling was used to analyze natural compounds in a 70% ethanol ginseng extract, which was directly infused into a 15 T Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer for less than 10 min without a separation process. Results The UHR FT-ICR MS yielded a mass accuracy of 0.5 ppm and a mass resolving power (m/?m) of 1,000,000–270,000 for the range m/z 290–1,100. The mass resolution was sufficient to resolve the isotopic fine structure (IFS) of many compounds in the extract. After noise removal from 1,552 peaks, 405 compounds were detected. The molecular formulae of 123 compounds, including 33 ginsenosides, were determined using the observed IFS, exact monoisotopic mass, and exact mass difference. Liquid chromatography (LC)/FT-ICR MS of the extract was performed to compare the high-throughput performance of UHR ESI FT-ICR MS. The LC/FT-ICR MS detected only 129 compounds, including 19 ginsenosides. The result showed that UHR ESI FT-ICR MS identified three times more compounds than LC/FT-ICR MS and in a relatively shorter time. The molecular formula determination by UHR FT-ICR MS was validated by LC and tandem MS analyses of three known ginsenosides. Conclusions UHR mass profiling of a plant extract by 15 T FT-ICR MS showed that multiple compounds were simultaneously detected and their molecular formulae were decisively determined by a single experiment with ultra-high mass resolution and mass accuracy. Simultaneous molecular determination of multiple natural products by UHR ESI FT-ICR MS would be a powerful method to profile a wide range of natural compounds.

2013-01-01

70

Determination of rhodium by resonance light-scattering technique coupled with solid phase extraction using Rh(III) ion-imprinted polymers as sorbent.  

PubMed

A resonance light-scattering method (RLS) for the determination of Rh(III) was initially developed, based on the reaction among Rh(III), WO4(2-) and ethylrhodamine B. The method possesses high sensitivity, but lacks selectivity. Therefore, a Rh(III) ion-imprinted polymer (IIP), prepared by precipitation polymerization using 2-(allylthio)nicotinic acid (ANA) as functional monomer, was used as sorbent to construct a ion-imprint based solid-phase extraction (IIP-SPE) method for separation of rhodium from complicated matrices prior to its determination by RLS. The experimental parameters affecting the extraction efficiency and selectivity of IIP-SPE were studied carefully. Under the optimal conditions, the IIP-SPE column with the enrichment factor (EF) of 10 could be used at least 20 times without decreasing its extraction recovery (above 90%) significantly. The calibration graph for the determination of rhodium by RLS coupled with IIP-SPE procedure was linear in the range of 0.06-1.5 ng mL(-1) with the detection limit of 0.024 ng mL(-1). There is no metal ions tested at the concentration below 10 ng mL(-1) interfered in the determination of 0.8 ng mL(-1) Rh(III). The proposed IIP-SPE-RLS method was successfully applied to the extraction and measurement of trace rhodium in catalyst, water and geochemical samples with the relative standard deviation (RSD) of less than 4.0% (n=4). PMID:23597998

Yang, Bing; Zhang, Ting; Tan, Wenxiang; Liu, Peng; Ding, Zhongtao; Cao, Qiue

2012-12-05

71

Application of high performance liquid chromatography coupled to on-line solid-phase extraction-nuclear magnetic resonance spectroscopy for the analysis of degradation products of V-class nerve agents and nitrogen mustard  

Microsoft Academic Search

The detection and identification of the degradation products of nitrogen mustard and nerve agent VX by high performance liquid chromatography coupled to on-line solid-phase extraction-nuclear magnetic resonance spectroscopy (HPLC-UV-SPE-NMR) were demonstrated. The analytes selected for the study were N,N-dimethylaminoethanol (DMAE), N,N-diethylaminoethanol (DEAE), N,N-diisopropylaminoethanol (DIAE) and triethanolamine (TEA). Offline solid-phase extraction (SPE) followed by derivatization was applied to eliminate the interferents

Avik Mazumder; Ajeet Kumar; Ajay K. Purohit; Devendra K. Dubey

2010-01-01

72

Comparison of analytical and semi-preparative columns for high-performance liquid chromatography-solid-phase extraction-nuclear magnetic resonance.  

PubMed

The application of analytical and semi-preparative columns in reversed-phase liquid chromatography-solid-phase extraction-nuclear magnetic resonance (HPLC-SPE-NMR) was compared. The work was aiming at separating a higher sample amount in a single run and in this way to reduce the necessary NMR measurement time of separated compounds. Several parameters for compound separation and trapping procedures were optimised: flow rate of HPLC and make-up water pumps, choice of stationary phase cartridges and drying time. The separation and loadability of nine model compounds on analytical and semi-preparative columns was determined, as well as the focussing capacity of SH-type SPE cartridges. It was found that a semi-preparative column--or multiple peak trapping on analytical columns--gave better results than a standard 4.6mm analytical column for non-polar compounds (e.g. flavonoid aglycones, sesquiterpene lactones, non-polar terpenes, logP>2), but for polar compounds (logP<-2) did not offer any advantage over an analytical column, or was even disadvantageous. For intermediately polar compounds (-2

Miliauskas, Giedrius; van Beek, Teris A; de Waard, Pieter; Venskutonis, Rimantas P; Sudhölter, Ernst J R

2005-12-20

73

Non-targeted analysis of wastewater treatment plant effluents by high performance liquid chromatography-time slice-solid phase extraction-nuclear magnetic resonance/time-of-flight-mass spectrometry.  

PubMed

Extracts of effluents from two different wastewater treatment plants (WWTP) in Switzerland taken during the application period of pesticides were examined by coupling an HPLC-MS system to a nuclear magnetic resonance spectrometer using a post column peak trapping device. By trapping 1 min portions of the chromatogram onto post column solid phase extraction cartridges (time slice-SPE-NMR) a comprehensive overview of proton carrying constituents could be achieved. Non-supervised statistical analysis of the NMR spectra obtained by this approach revealed NMR resonances pointing to contaminants present in decreasing proton concentration in the extracts. Comparison of exact mass data acquired during the trapping process to these NMR resonances enabled the identification of the pesticides Linuron, Metazachlor, Ethofumesate, Isoproturon, Metamitron, Propazine and Chloridazon. Desaminometamitron, a known transformation product of Metamitron could also be identified together with unexpected highly concentrated C8, C10 and C12 fatty acids and their glycerol mono- and di esters. Other compounds identified were a drug metabolite (3-Carboxymefenamic acid), a sun screen agent (Ensulizole: 2-Phenyl-1H-1,3-benzodiazole-6-sulfonic acid) and industrial chemicals (Benzotriazole, N-Benzyl-indole). In addition, a number of well-resolved proton spectra cannot be attributed to a mass response showing the need of further investigations using 2D-NMR and different ionization techniques. PMID:22098937

Godejohann, Markus; Berset, Jean-Daniel; Muff, Daniel

2011-10-28

74

Resonances and resonance widths  

SciTech Connect

Two-dimensional betatron resonances are much more important than their simple one-dimensional counterparts and exhibit a strong dependence on the betatron phase advance per cell. A practical definition of ''width'' is expanded upon in order to display these relations in tables. A primarily pedagogical introduction is given to explain the tables, and also to encourage a wider capability for deriving resonance behavior and wider use of ''designer'' resonances.

Collins, T.

1986-05-01

75

Metabolomics of transgenic maize combining Fourier transform-ion cyclotron resonance-mass spectrometry, capillary electrophoresis-mass spectrometry and pressurized liquid extraction  

Microsoft Academic Search

In this work, the potential of combining capillary electrophoresis-time-of-flight-mass spectrometry (CE-TOF-MS) and Fourier transform-ion cyclotron resonance-mass spectrometry (FT-ICR-MS) for metabolomics of genetically modified organisms (GMOs) is demonstrated. Thus, six different varieties of maize, three of them transgenic (PR33P66 Bt, Tietar Bt and Aristis Bt) and their corresponding isogenic lines (PR33P66, Tietar and Aristis) grown under the same field conditions, were

Carlos Leon; Irene Rodriguez-Meizoso; Marianna Lucio; Virginia Garcia-Cañas; Elena Ibañez; Philippe Schmitt-Kopplin; Alejandro Cifuentes

2009-01-01

76

Coal liquefaction process streams characterization and evaluation. Characterization of coal-derived materials by field desorption mass spectrometry, two-dimensional nuclear magnetic resonance, supercritical fluid extraction, and supercritical fluid chromatography/mass spectrometry  

SciTech Connect

Under contract from the DOE , and in association with CONSOL Inc., Battelle, Pacific Northwest Laboratory (PNL) evaluated four principal and several complementary techniques for the analysis of non-distillable direct coal liquefaction materials in support of process development. Field desorption mass spectrometry (FDMS) and nuclear magnetic resonance (NMR) spectroscopic methods were examined for potential usefulness as techniques to elucidate the chemical structure of residual (nondistillable) direct coal liquefaction derived materials. Supercritical fluid extraction (SFE) and supercritical fluid chromatography/mass spectrometry (SFC/MS) were evaluated for effectiveness in compound-class separation and identification of residual materials. Liquid chromatography (including microcolumn) separation techniques, gas chromatography/mass spectrometry (GC/MS), mass spectrometry/mass spectrometry (MS/MS), and GC/Fourier transform infrared (FTIR) spectroscopy methods were applied to supercritical fluid extracts. The full report authored by the PNL researchers is presented here. The following assessment briefly highlights the major findings of the project, and evaluates the potential of the methods for application to coal liquefaction materials. These results will be incorporated by CONSOL into a general overview of the application of novel analytical techniques to coal-derived materials at the conclusion of CONSOL`s contract.

Campbell, J.A.; Linehan, J.C.; Robins, W.H. [Battelle Pacific Northwest Lab., Richland, WA (United States)

1992-07-01

77

Alkaloid analysis by high-performance liquid chromatography-solid phase extraction-nuclear magnetic resonance: new strategies going beyond the standard.  

PubMed

The hyphenated technique HPLC-SPE-NMR is an important tool for rapid dereplication of complex mixtures of in particular small molecules and has been successfully employed in natural product research. However, positively charged alkaloids at low pH are often poorly trapped on the generally used SPE cartridge limiting the general application of the procedure. In this work, two new approaches for efficient SPE trapping of alkaloids and elution efficiencies were evaluated using 24 model alkaloids. Use of a 0.1 M NaOH solution as the post-column dilution greatly enhanced trapping of alkaloids on the commonly used cartridge containing divinylbenzene polymer (GP resin). This procedure, however, was unsuitable for trapping phenolic alkaloids. Severe line broadening and immiscibility with water made chloroform-d(1) unsuited as eluent. None of these problems occurred when methanol-d(4) was used as eluent. Previously, mixed mode cation exchange sorbents have not been used in HPLC-SPE-NMR analysis of natural products. In contrast to GP resin this material showed good retention and elution characteristics for retention and elution of alkaloids. As well the use of methanol-d(4) containing 1% aqueous NaOD (40%) as methanol-d(4) containing 5% aqueous NH(4)OH (30%) as eluents were successful, even though elution of alkaloids with pK(a) of the corresponding acid above 10 proved difficult. Alkaloid extracts of Huperzia selago containing complex aliphatic alkaloids and Triclisia patens containing bisbenzylisoquinoline alkaloids were used for validation of the protocols for analysis of a diverse collection of alkaloids. Mixed mode cation exchange sorbent was efficient for trapping and elution of both types of alkaloids as evidenced by acquisition of 2D NMR data for all trapped compounds. In contrast, GP resin proved only viable for all the H. selago alkaloids whereas trapping and elution of bisbenzylisoquinoline alkaloids were dubious. PMID:23195707

Johansen, Kenneth T; Ebild, Sarah J; Christensen, S Brøgger; Godejohann, Markus; Jaroszewski, Jerzy W

2012-11-09

78

Stochastic resonance  

NASA Astrophysics Data System (ADS)

Over the last two decades, stochastic resonance has continuously attracted considerable attention. The term is given to a phenomenon that is manifest in nonlinear systems whereby generally feeble input information (such as a weak signal) can be be amplified and optimized by the assistance of noise. The effect requires three basic ingredients: (i) an energetic activation barrier or, more generally, a form of threshold; (ii) a weak coherent input (such as a periodic signal); (iii) a source of noise that is inherent in the system, or that adds to the coherent input. Given these features, the response of the system undergoes resonance-like behavior as a function of the noise level; hence the name stochastic resonance. The underlying mechanism is fairly simple and robust. As a consequence, stochastic resonance has been observed in a large variety of systems, including bistable ring lasers, semiconductor devices, chemical reactions, and mechanoreceptor cells in the tail fan of a crayfish. In this paper, the authors report, interpret, and extend much of the current understanding of the theory and physics of stochastic resonance. They introduce the readers to the basic features of stochastic resonance and its recent history. Definitions of the characteristic quantities that are important to quantify stochastic resonance, together with the most important tools necessary to actually compute those quantities, are presented. The essence of classical stochastic resonance theory is presented, and important applications of stochastic resonance in nonlinear optics, solid state devices, and neurophysiology are described and put into context with stochastic resonance theory. More elaborate and recent developments of stochastic resonance theory are discussed, ranging from fundamental quantum properties-being important at low temperatures-over spatiotemporal aspects in spatially distributed systems, to realizations in chaotic maps. In conclusion the authors summarize the achievements and attempt to indicate the most promising areas for future research in theory and experiment.

Gammaitoni, Luca; Hänggi, Peter; Jung, Peter; Marchesoni, Fabio

1998-01-01

79

Dibaryon Resonances.  

National Technical Information Service (NTIS)

New degrees of freedom, like mesons and baryonic resonance on one band, or quarks and color on the other hand, can lead to possible exotic states of baryonic number 2. Large resonances have indeed been observed in both elastic and inelastic nucleon-nucleo...

B. Mayer

1987-01-01

80

Padé approximants and resonance poles  

NASA Astrophysics Data System (ADS)

Based on the mathematically well defined Padé theory, a theoretically safe new procedure for the extraction of the pole mass and width of a resonance is proposed. In particular, thanks to the Montessus de Ballore theorem we are able to unfold the second Riemann sheet of an amplitude to search for the position of the resonance pole in the complex plane. The method is systematic and provides a model-independent treatment of the prediction and the corresponding errors of the approximation. Likewise, it can be used in combination with other well-established approaches to improve future determinations of resonance parameters.

Masjuan, Pere; Sanz-Cillero, Juan José

2013-10-01

81

Coupling considerations for ring resonators  

Microsoft Academic Search

The present work quantitatively compares the extraction efficiency obtainable in traveling-wave geometries with that characteristic of standing-wave configurations and calculates the optimum coupling to employ in traveling-wave geometries, i.e., that coupling which maximizes power extraction from the medium. The analysis assumes that the resonator ring is operating in a unidirectional fashion achieved, for example, by the inclusion of a feedback

A. C. Eckbreth

1975-01-01

82

Wireless interrogation techniques for sensors utilizing inductively coupled resonance circuits  

Microsoft Academic Search

The methods needed to interrogate passive resonance sensors are studied. A portable impedance measurement unit and the methods to extract a coupling coefficient compensated resonance frequency are presented. The interrogation methods are demonstrated with ECG and pressure measurements. The results show that the quality of the ECG signal measured with a flexible textile coil is sufficient to extract the heart

Timo Salpavaara; Jarmo Verho; Pekka Kumpulainen; Jukka Lekkala

2010-01-01

83

Electric and magnetic resonances in symmetric pairs of split ring resonators  

NASA Astrophysics Data System (ADS)

Orientation of the gap of a split ring resonator determines whether the resonance is an electric or magnetic response. When the gap of a split ring resonator is parallel to the incident E-field, an electric resonance is excited, and when the gap is perpendicular to the E-field, a magnetic resonance is excited. In this paper, we show that strong coupling between adjacent symmetric split ring resonators can give rise to dual electric and magnetic resonances if the intercell spacing is small enough. By varying the interparticle spacing within a unit cell, we can position the dual resonances as desired. Inverting the simulated reflection and transmission coefficients of a periodic slab of symmetric pairs of split ring resonators, the permittivity and permeability can be extracted and are shown to result in negative properties at resonance. Through a careful analysis of the extracted and Lorentz model fits of the permittivity and permeability, together with the simulated S-parameters, we have established a clear guideline for identifying electric and magnetic resonances. We also present measurement data that agree well with our simulated data. Applications of this design to band-pass filters and microstrip antenna substrates are envisaged.

Kim, In Kwang; Varadan, Vasundara V.

2009-10-01

84

Antioxidant properties of marigold extracts  

Microsoft Academic Search

The influence of methanolic and water extracts of growing wild marigold, Calendula arvensis L. (GWM) and cultivated marigold, Calendula officinalis L. (CM), in a concentration range of 0.10–0.90 mg\\/ml, was evaluated on three different free-radical species: 2,2-diphenyl-1-picrylhydrazyl free radical (DPPH), hydroxyl radical and lipid peroxyl radical using electron spin resonance (ESR) spectroscopy. These extracts of CM and GWM, scavenged all

Gordana S ?etkovi?; Sonja M Djilas; Jasna M ?anadanovi?-Brunet; Vesna T Tumbas

2004-01-01

85

Resonant behavior of dielectric objects (electrostatic resonances).  

PubMed

Resonant behavior of dielectric objects occurs at certain frequencies for which the object permittivity is negative and the free-space wavelength is large in comparison with the object dimensions. Unique physical features of these resonances are studied and a novel technique for the calculation of resonance values of permittivity, and hence resonance frequencies, is proposed. Scale invariance of resonance frequencies, unusually strong orthogonality properties of resonance modes, and a two-dimensional phenomenon of "twin" spectra are reported. The paper concludes with brief discussions of optical controllability of these resonances in semiconductor nanoparticles and a plausible, electrostatic resonance based, mechanism for nucleation and formation of ball lightning. PMID:14754117

Fredkin, D R; Mayergoyz, I D

2003-12-19

86

Structure and dynamical evolution of low lying nucleon resonances  

SciTech Connect

The dynamical origins of the two poles associated with the Roper resonance are examined. Both of them together with the next higher resonance in the P11 partial wave are found to have the same originating bare state, indicating that the coupling to the meson-baryon continuum induces multiple observed resonances from the same bare state. Concerning other partial waves, the resonance poles extracted within the same multi-channels multi-resonances model of pi N reactions are compared to those listed by the Particle Data Group (PDG). Within our reaction model, all the identified resonances consist of a core state and meson-baryon components.

Nobuhiko Suzuki, Bruno Julia Diaz, Hiroyuki Kamano, Tsung-Shung Lee, Akihiko Matsuyama, Toru Sato

2010-01-01

87

Gravitoelectromagnetic resonances  

NASA Astrophysics Data System (ADS)

The interaction between gravitational and electromagnetic radiation has a rather long research history. It is well known, in particular, that gravity-wave distortions can drive propagating electromagnetic signals. Since forced oscillations provide the natural stage for resonances to occur, gravitoelectromagnetic resonances have been investigated as a means of more efficient gravity-wave detection methods. In this report, we consider the coupling between the Weyl and the Maxwell fields on a Minkowski background, which also applies to astrophysical environments where gravity is weak, at the second perturbative level. We use covariant methods that describe gravitational waves via the transverse component of the shear, instead of pure-tensor metric perturbations. The aim is to calculate the properties of the electromagnetic signal, which emerges from the interaction of its linear counterpart with an incoming gravitational wave. Our analysis shows how the wavelength and the amplitude of the gravitationally driven electromagnetic wave vary with the initial conditions. More specifically, for certain initial data, the amplitude of the induced electromagnetic signal is found to diverge. Analogous, diverging, gravitoelectromagnetic resonances were also reported in cosmology. Given that, we extend our Minkowski space study to cosmology and discuss analogies and differences in the physics and in the phenomenology of the Weyl-Maxwell coupling between the aforementioned two physical environments.

Tsagas, Christos G.

2011-08-01

88

Electroexcitation of nucleon resonances  

NASA Astrophysics Data System (ADS)

We review recent progress in the investigation of the electroexcitation of nucleon resonances, both in experiment and in theory. We describe current experimental facilities, the experiments performed on ? and ? electroproduction off protons, and theoretical approaches used for the extraction of resonance contributions from the experimental data. The status of 2?, K?, and K? electroproduction is also presented. The most accurate results have been obtained for the electroexcitation amplitudes of the four lowest excited states, which have been measured in a range of Q2 up to 8 and 4.5 GeV 2 for ?(1232)P33, N(1535)S11 and N(1440)P11, N(1520)D13, respectively. These results have been confronted with calculations based on lattice QCD, large-Nc relations, perturbative QCD (pQCD), and QCD-inspired models. The amplitudes for the ?(1232) indicate large pion-cloud contributions at low Q2 and do not show any sign of approaching the pQCD regime for Q2<7GeV. Measured for the first time, the electroexcitation amplitudes of the Roper resonance, N(1440)P11, provide strong evidence for this state as a predominantly radial excitation of a three-quark (3q) ground state, with additional non-3-quark contributions needed to describe the low Q2 behavior of the amplitudes. The longitudinal transition amplitude for the N(1535)S11 was determined and has become a challenge for quark models. Explanations may require large meson-cloud contributions or alternative representations of this state. The N(1520)D13 clearly shows the rapid changeover from helicity-3/2 dominance at the real photon point to helicity-1/2 dominance at Q2>0.5GeV, confirming a long-standing prediction of the constituent quark model. The interpretation of the moments of resonance transition form factors in terms of transition transverse charge distributions in infinite momentum frame is presented.

Aznauryan, I. G.; Burkert, V. D.

2012-01-01

89

Differential cross section and polarization extractions for gamma p going to K+sigma0 and gamma p going to phi p using CLAS at Jefferson Lab, towards a partial wave analysis in search of missing baryon resonances  

NASA Astrophysics Data System (ADS)

In the first part of this work, we present differential cross section and polarization measurements for the reactions gammap ? K+Sigma0 and gammap ? ?p. The data were collected using the large-acceptance CLAS detector stationed in Ball B at Jefferson Lab. An unpolarized energy-tagged photon beam produced via bremsstrahlung and a liquid hydrogen cryotarget was used for this, during the so-called g11a experimental run-period. The kinematic coverage of our results is from near production threshold to s = 2.84 GeV in energy and -0.95 ? costhetac.m. ? +0.95 in the meson production angle thetac.m.. For the most part, our results are finely binned in 10-MeV-wide s bins. For the ?p channel, we analyze both the charged (? ? K+K -) and the neutral (? ? K0SK0L ) decay modes. For K+Sigma 0, our work corresponds to a 300 MeV increase in energy coverage for the differential cross sections and forms the first extensive recoil polarization world dataset. For ?p, where previous world data is either non-existent or exist with wide energy bins and very limited statistics, our results will be the first extensive world dataset for both the cross sections and the spin density matrix elements r0MM' . Our K+Sigma0 results are now published as PRC 82, 025202 (2010) [1] and the ?p results are also nearing completion of internal Collaboration analysis review. In addition, we have also been able to extend upon a previous K+? analysis in the backward-angles and near-threshold kinematic regimes, using a higher statistics dataset. The second segment consists of setting up a general framework for performing a coupled-channel partial wave analysis (PWA) on these extracted data results. Our final goal is to search for the so-called "missing" baryon resonances, that is, states predicted by quark models, but absent in conventional piN analyses. We construct the amplitudes and polarization observables required for this PWA. For polarizations in the pseudo-scalar sector, sign discrepancies due to different conventions adopted by different authors in the field are treated in a systematic manner and this study has been published as PRC 83, 055208 (2011) [2]. During our preliminary PWA, we found that certain normalization discrepancies exist between CLAS and older higher energy data from SLAC/DESY/CEA. A systematic global study of these normalization issues and their effect on the coupling constants in hadrodynamic model is presented. Our PWA is an ongoing work and the rich set of data results and analysis tools obtained here will provide a strong impetus for continuing investigations.

Dey, Biplab

90

All-resonant control of superconducting resonators.  

PubMed

An all-resonant method is proposed to control the quantum state of superconducting resonators. This approach uses a tunable artificial atom linearly coupled to resonators, and allows for efficient routes to Fock state synthesis, qudit logic operations, and synthesis of NOON states. This resonant approach is theoretically analyzed, and found to perform significantly better than existing proposals using the same technology. PMID:23215585

Strauch, Frederick W

2012-11-20

91

All-Resonant Control of Superconducting Resonators  

NASA Astrophysics Data System (ADS)

An all-resonant method is proposed to control the quantum state of superconducting resonators. This approach uses a tunable artificial atom linearly coupled to resonators, and allows for efficient routes to Fock state synthesis, qudit logic operations, and synthesis of NOON states. This resonant approach is theoretically analyzed, and found to perform significantly better than existing proposals using the same technology.

Strauch, Frederick W.

2012-11-01

92

If It's Resonance, What is Resonating?  

ERIC Educational Resources Information Center

|The phenomenon under the name "resonance," which, is based on the mathematical analogy between mechanical resonance and the behavior of wave functions in quantum mechanical exchange phenomena was described. The resonating system does not have a structure intermediate between those involved in the resonance, but instead a structure which is…

Kerber, Robert C.

2006-01-01

93

Investigation of Non-Linear Estimation of Natural Resonances in Target Identification.  

National Technical Information Service (NTIS)

This investigation considers a non-linear technique for extracting natural resonances from transient electromagnetic scattering responses of radar targets. These natural resonances represent the complex poles of the target's transfer function in the Lapla...

C. Y. Chong

1983-01-01

94

Dendritic versus somatic resonance  

Microsoft Academic Search

Here, we investigate to what extent and under which circumstances cells with dendritic resonance may be misclassified as nonresonant by somatic measurement of resonance properties. We use simple conductance-based multicompartmental models to analyze the effect of dendritic resonance on somatic input (and hence resonance estimates based on somatic recordings). We find that indeed, even a strong dendritic resonance may not

Ekaterina A Zhuchkova; Susanne Schreiber

2011-01-01

95

Microwave energy storage in resonant cavities  

SciTech Connect

One method of generating short, high-power microwave pulses is to store rf energy in a resonant cavity over a relatively long fill time and extract is rapidly. A power gain roughly equal to the ratio of fill time to extraction time can be obtained. During the filling of a resonant cavity some of the energy is lost in heating the cavity walls, and some will generally be reflected at the input coupling of the cavity. In this paper we discuss the time dependence of the stored energy and related quantities and the way in which it depends on the coupling of the source to the cavity.

Alvarez, R.A.

1983-02-01

96

Resonant charging  

NASA Astrophysics Data System (ADS)

It has been shown (Athas et al., 1994) that adiabatic switching can significantly reduce the dynamic power dissipation in an integrated circuit. Due to the overhead in the realization of adiabatic logic blocks (Saas et al., 2000) the best results are achieved when it is used only for charging dominant loads in an integrated circuit (Voss and Glessner, 2001). It has been demonstrated (Saas et al., 2001) that a multi stage driver is needed for minimal power dissipation. In this article a complete three stage driver including the generation of oscillating supply is described. To obtain a minimal power dissipation during synchronization the resonant frequency has to be constant. Therefore the waveforms for the logic states of the signal and the realization of a single stage differ from those presented in (Saas et al., 2001). In the H-SPICE simulations losses of the inductor are taken into account. This allows to estimate the power reduction that is achievable in a real system.

Saas, C.; Nossek, J. A.

2003-05-01

97

Extraction faults  

NASA Astrophysics Data System (ADS)

We propose the term “extraction fault” for a planar structure that forms at the trailing edge of a discrete block when it is forced or extracted out of the surrounding material. This process results in the merging of two block-bounding faults with opposite senses of displacement. An extraction fault differs fundamentally from other faults in that its two sides have approached each other substantially in the direction perpendicular to the fault. The fault-parallel displacement may be either zero (pure extraction faults) or not (mixed extraction faults). Pure small-scale extraction faults can result from boudinage. A large-scale example may be the S-reflector of the Galicia passive continental margin which is related to rifting and continental breakup. When the strong portion of the lithosphere, i.e. the upper mantle and the lower crust, underwent necking, thermally weak mantle from below and upper crust from above collapsed into the opening gap in the rift centre and an extraction fault formed at the trailing edge of the strong lithosphere. Extraction faults are also potentially important in the exhumation of high-pressure metamorphic rocks in collisional orogens. We propose that the Combin fault on top of the eclogite-facies Zermatt-Saas ophiolites in the Penninic Alps, earlier interpreted either as a normal fault or as a thrust, is in fact an extraction fault.

Froitzheim, Nikolaus; Pleuger, Jan; Nagel, Thorsten J.

2006-08-01

98

Heavy ion excitation and photon decay of giant resonances  

SciTech Connect

Results are presented for excitation of giant multipole resonances by inelastic scattering of 350 and 500 MeV /sup 16/O projectiles from /sup 90/Zr and /sup 208/Pb. The giant quadrupole resonance is excited with large cross sections and a very large resonance peak to continuum ratio is obtained. Extracted cross sections agree with DWBA calculations which use standard collective model form factors. Using 380 MeV 170 to excite the giant resonances, the ..gamma..-ray decay has been measured for the giant quadrupole resonance region of /sup 208/Pb. 10 references.

Bertrand, F.E.; Beene, J.R.; Sjoreen, T.P.

1983-01-01

99

Contour extraction from cardiac MRI studies using snakes  

Microsoft Academic Search

The author investigated automatic extraction of left ventricular contours from cardiac magnetic resonance imaging (MRI) studies. The contour extraction algorithms were based on active contour models, or snakes. Based on cardiac MR image characteristics, the author suggested algorithms for extracting contours from these large data sets. The author specifically considered contour propagation methods to make the contours reliable enough despite

Surendra Ranganath

1995-01-01

100

Automatic extraction and matching of neonatal cerebral vasculature  

Microsoft Academic Search

This paper presents a method for extracting and matching the neonatal cerebral vasculature from magnetic resonance angiography-time of flight (MRA-TOF) images. The vasculature is first extracted using a fully automatic version of the ridge traversal algorithm. Extracted vessel segments are then connected iteratively to compose a vessel tree that is automatically labeled. After this, an indirect vasculature registration method is

Hui Xue; Christina Malamateniou; Joanna M. Allsop; Latha Srinivasan; Joseph V. Hajnal; Daniel Rueckert

2006-01-01

101

Artificial Dielectric Resonator Made of Spherical Metal Particles  

NASA Astrophysics Data System (ADS)

A microwave resonator is fabricated by a lump of spherical metal particles for the first time. It is the evidence that those particles constitute artificial dielectrics. The effective permittivity is calculated numerically together with the permeability. Resonant mode frequencies in the experiment are compared with the theoretical result obtained by the effective material constants above. Their reasonable agreement indicates the validity of material constant extraction. The unique diamagnetism of spherical particles could be utilized for improvement of spurious property of a resonator.

Awai, Ikuo; Mizue, Osamu; Saha, Arun Kumar

102

Resonant phenomena in conductor-backed coplanar waveguides (CBCPW's)  

Microsoft Academic Search

A thorough and systematic investigation of resonant phenomena in conductor-backed coplanar waveguides (CBCPWs) is reported. A rigorous three dimensional full-wave space-domain integral equation method accompanied by an S-parameter extraction technique is used. A series of measurements has been conducted to confirm the theoretical results. A patch-resonator model and a microstriplike (MSL) model are employed to understand the origin of resonance

Wen-Teng Lo; C.-K. C. Tzuang; S.-T. Peng; Ching-Cheng Tien; Chung-Chi Chang; Jenq-Wen Huang

1993-01-01

103

Bevalac extraction  

SciTech Connect

This report will describe some of the general features of the Bevatron extraction system, primarily the dependence of the beam parameters and extraction magnet currents on the Bevalac field. The extraction magnets considered are: PFW, XPl, XP2, XS1, XS2, XM1, XM2, XM3, XQ3A and X03B. This study is based on 84 past tunes (from 1987 to the present) of various ions (p,He,O,Ne,Si,S,Ar,Ca,Ti,Fe,Nb,La,Au and U), for Bevalac fields from 1.749 to 12.575 kG, where all tunes included a complete set of beam line wire chamber pictures. The circulating beam intensity inside the Bevalac is measured with Beam Induction Electrodes (BIE) in the South Tangent Tank. The extracted beam intensity is usually measured with the Secondary Emission Monitor (SEM) in the F1-Box. For most of the tunes the extraction efficiency, as given by the SEM/BIE ratio, was not recorded in the MCR Log Book, but plotting the available Log Book data as a function of the Bevalac field, see Fig.9, we find that the extraction efficiency is typically between 30->60% with feedback spill.

Kalnins, J.G.; Krebs, G.; Tekawa, M.; Cowles, D.; Byrne, T.

1992-02-01

104

Unstable resonators with excited converging wave  

SciTech Connect

This paper reports the properties of unstable resonators with an additional mirror inside or outside the resonator investigated, both experimentally and theoretically. The additional mirror excites the converging wave, and by this, output coupling is decreased without affecting beam quality. Experiments were performed with a pulsed Nd:YAG system. The theoretical model was based on the coupled Kirchhoff integrals and solved numerically. Agreement between theory and experiments indicates that this kind of resonator provides high focusability and maximum extraction efficiency simultaneously, even with low-gain media. This enables one to apply unstable resonators to solid-state lasers with low small-signal gain, like alexandrite or CW-pumped Nd:YAG.

Hodgson, N. (Optisches Institut, Technische Universitat Berlin, Strasse des 17. Juni 135, 1000 Berlin 12 (DE)); Weber, H. (Festkoerper-Laser-Institut Berlin GmbH, Strasse des 17, Juni 135, 1000 Berlin (DE))

1990-04-01

105

Resonances in a finite volume  

SciTech Connect

We review applications of effective field theory methods in a finite volume for the extraction of the characteristics of unstable particles from lattice QCD calculations. In particular, the scalar mesons f{sub 0}(980),a{sub 0}(980) are considered. We formulate criteria that distinguish between hadronic molecules and tightly bound quark states, as well as between the ordinary qq-bar and the tetraquark states. Using these criteria will enable one to study the nature of scalar mesons on the lattice. Further, we also formulate a procedure to calculate resonance matrix elements on the lattice by using the background field method.

Bernard, V. [Groupe de Physique Theorique, Universite de Paris-Sud-XI/CNRS, F-91406 Orsay (France); Hoja, D.; Lage, M.; Rusetsky, A. [Helmholtz-Institut fuer Strahlen- und Kernphysik, Universitaet Bonn and Bethe Center for Theoretical Physics, D-53115 Bonn (Germany); Meissner, U.-G. [Helmholtz-Institut fuer Strahlen- und Kernphysik, Universitaet Bonn and Bethe Center for Theoretical Physics, D-53115 Bonn (Germany); Forschungszentrum Juelich, Juelich Center for Hadron Physics, Institut fuer Kernphysik (Theorie), and Institute for Advanced Simulation (IAS-4), D-52425 Juelich (Germany)

2011-10-21

106

Extractant composition  

DOEpatents

An organic extracting solution useful for separating elements of the actinide series of the periodic table from elements of the lanthanide series, where both are in trivalent form. The extracting solution consists of a primary ligand and a secondary ligand, preferably in an organic solvent. The primary ligand is a substituted monothio-1,3-dicarbonyl, which includes a substituted 4-acyl-2-pyrazolin-5-thione, such as 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione (BMPPT). The secondary ligand is a substituted phosphine oxide, such as trioctylphosphine oxide (TOPO).

Smith, Barbara F. (Los Alamos, NM); Jarvinen, Gordon D. (Los Alamos, NM); Ryan, Robert R. (Los Alamos, NM)

1990-01-01

107

Versatile Magnetic Resonance Spectrometer  

Microsoft Academic Search

A Pound-Knight-Watkins marginal oscillator has been modified by the addition of a vibrating capacitor in parallel with the tuning capacitor to produce a simple circuit which may be used to observe paramagnetic resonance at low fields, nuclear magnetic resonance, and nuclear quadrupole resonance. Suggestions are made as to the type of information which may be obtained in an undergraduate laboratory

J. A. Cowen; W. H. Tanttila

1958-01-01

108

VERSATILE MAGNETIC RESONANCE SPECTROMETER  

Microsoft Academic Search

A Pound-Knight-Watkins marginal osciliator was modified by the addition ; of a vibrating capacitor in parallel with the tuning capacitor to produce a ; simple circuit which may be used to observe paramagnetic resonance at low fields, ; nuclear magnetic resonance, and nuclear quadrupole resonance. Suggestions are ; mnde as to the type of information which may be obtained in

J. A. Cowen; W. H. Tanttila

1958-01-01

109

Nuclear magnetic resonance spectroscopy  

Microsoft Academic Search

Magnetic resonance spectroscopy is a valuable method for the non-invasive investigation of metabolic processes and can now be combined with conventional magnetic resonance imaging in patients. This article gives a brief introduction into the principles and physiological and clinical applications of in vivo proton magnetic resonance spectroscopy, surveys experiences in healthy volunteers and presents exemplary results in patients suffering from

Armin Ettl; Christa Fischer-Klein; Andreas Chemelli; Albert Daxer; Stephan Felber

1994-01-01

110

Photonic microdisk resonators in aluminum nitride  

NASA Astrophysics Data System (ADS)

We demonstrate integrated photonic microdisk resonators in sputtered c-axis oriented aluminum nitride (AlN) films. A 400 nm thick layer of AlN was patterned in a single lithography step with silicon dioxide used for the top and bottom cladding layers. AlN disks with a radius of 20 ?m at various spacings to an 850 nm wide waveguide were tested. A loaded quality factor of 28 350 is shown in these microdisks, with an extracted peak shift over power ratio of 0.0495 pm/?W. The demonstration of photonic resonators in a piezoelectric material can lead to novel optomechanical functionalities.

Ghosh, Siddhartha; Piazza, Gianluca

2013-01-01

111

Cross sections for resonant vibrational excitation of Nâ by electron impact  

Microsoft Academic Search

We report the results of a theoretical study of resonant vibrational-excitation of Nâ by low-energy electrons. The vibrational-excitation cross sections were calculated using ab initio fixed-nuclei resonance parameters in the complex-potential or ''boomerang'' model of Dube and Herzenberg. The electronic resonance energy and decay width were extracted from several ab initio calculations of the ²Pi\\/sub g\\/ shape resonance of Nâ\\/sup

A. U. Hazi; T. N. Rescigno; M. Kurilla

1981-01-01

112

DNA Extraction  

NSDL National Science Digital Library

Teachers' Domain presents this interactive, adapted from the University of Nebraska's Plant and Soil Science eLibrary, with reading material and animations to help students learn the basics of DNA extraction. The lesson is divided into and introduction and the four processes involved: cell lysis, dismantling the cell membrane, removing unwanted cell parts, and precipitating the DNA. On the site, visitors will also find a supplemental background essay, discussion questions, and standards alignment from Teachers' Domain.

2010-10-07

113

URANIUM EXTRACTION  

DOEpatents

The recovery of uranium values from uranium ore such as pitchblende is described. The ore is first dissolved in nitric acid, and a water soluble nitrate is added as a salting out agent. The resulting feed solution is then contacted with diethyl ether, whereby the bulk of the uranyl nitrate and a portion of the impurities are taken up by the ether. This acid ether extract is then separated from the aqueous raffinate, and contacted with water causing back extractioa of the uranyl nitrate and impurities into the water to form a crude liquor. After separation from the ether extract, this crude liquor is heated to about 118 deg C to obtain molten uranyl nitrate hexahydratc. After being slightly cooled the uranyl nitrate hexahydrate is contacted with acid free diethyl ether whereby the bulk of the uranyl nitrate is dissolved into the ethcr to form a neutral ether solution while most of the impurities remain in the aqueous waste. After separation from the aqueous waste, the resultant ether solution is washed with about l0% of its volume of water to free it of any dissolved impurities and is then contacted with at least one half its volume of water whereby the uranyl nitrate is extracted into the water to form an aqueous product solution.

Harrington, C.D.; Opie, J.V.

1958-07-01

114

Resonant and non-resonant magnetic scattering  

SciTech Connect

The tunability and the polarization of synchrotron radiation open upon new possibilities for the study of magnetism. Studies on magnetic materials performed at the National Synchrotron Light Source are reviewed, and thy fall into four areas: structure, evolution of magnetic order, separation of L and S, and resonance effects. In the vicinity of atomic absorption edges, the Faraday effect, magnetic circular dichroism, and resonant magnetic scattering are all related resonance effects which measure the spin polarized density of states. The production and analysis of polarized beams are discussed in the context of the study of magnetism with synchrotron radiation.

McWhan, D.B.; Hastings, J.B.; Kao, C.C.; Siddons, D.P.

1991-12-31

115

Resonant and non-resonant magnetic scattering  

SciTech Connect

The tunability and the polarization of synchrotron radiation open upon new possibilities for the study of magnetism. Studies on magnetic materials performed at the National Synchrotron Light Source are reviewed, and thy fall into four areas: structure, evolution of magnetic order, separation of L and S, and resonance effects. In the vicinity of atomic absorption edges, the Faraday effect, magnetic circular dichroism, and resonant magnetic scattering are all related resonance effects which measure the spin polarized density of states. The production and analysis of polarized beams are discussed in the context of the study of magnetism with synchrotron radiation.

McWhan, D.B.; Hastings, J.B.; Kao, C.C.; Siddons, D.P.

1991-01-01

116

Signal Extraction and Optical Design for an Advanced Gravitational-Wave Interferometer  

Microsoft Academic Search

We present an experimental demonstration of a locking and con- trol scheme for an interferometer using a power-recycled resonant sideband extraction configuration, and show that the measured response to mirror vibrations matches an optical model. We discuss some aspects of resonant sideband extraction that are relevant to gravitational wave detection.

James E. Mason; Phil A. Willems

2003-01-01

117

Slow beam extraction from the Nuclotron  

Microsoft Academic Search

Experiments on beam extraction from the Nuclotron, a superferric heavy ion synchrotron, were carried out last year and in March, 2001. The resonance Qx=20\\/3, used for a horizontal betatron amplitude growth, provides a beam entering the electrostatic septum deflector, where it obtains an initial deflection to avoid losses on the septum of the Lambertson Magnet. The latter bends the beam

N. N. Agapov; V. A. Andreev; A. M. Baldin; N. A. Blinov; O. I. Brovko; V. N. Buldakovsky; A. V. Butenko; O. M. Golubitsky; A. I. Govorov; E. V. Ivanov; I. B. Issinsky; S. V. Kalenov; V. I. Kaplin; H. G. Khodigbagiyan; A. E. Kirichenko; A. G. Kochurov; A. D. Kovalenko; O. S. Kozlov; I. I. Kulikov; L. A. Leonov; A. I. Malakhov; E. A. Matyshevsky; I. N. Meshkov; V. A. Mikhailov; V. A. Monchinsky; P. I. Nikitaev; S. A. Novikov; S. V. Ronamov; P. A. Rukoyatkin; S. Z. Sayfulin; A. A. Smirnov; B. N. Sveshnikov; V. V. Seleznev; B. V. Vasilishin; M. A. Voevodin; V. I. Volkov; A. V. Vol'nov

2001-01-01

118

Hadronic resonances at ALICE  

NASA Astrophysics Data System (ADS)

Measurements of the ratios of hadronic resonance yields to non-resonance yields can be used to study the properties of the hadronic phase of high-energy heavy-ion collisions. A change in resonance masses or widths could be an indication of chiral symmetry restoration. Measurements of resonances in proton-proton collisions provide an important baseline for measurements in heavy-ion collisions as well as data for tuning QCD-inspired particle production models. The ALICE collaboration has measured the K*(892)0 and phi(1020) resonances in Pb-Pb collisions at = 2.76 TeV and the K*(892)0, phi(1020), and ?*(1385)± resonances in pp collisions at = 7 TeV. These measurements - including transverse momentum spectra, ratios to non-resonances, masses, and widths - are discussed and compared to theoretical predictions.

Knospe, A. G.; Alice Collaboration

2013-09-01

119

The resonant body transistor.  

PubMed

This paper introduces the resonant body transistor (RBT), a silicon-based dielectrically transduced nanoelectromechanical (NEM) resonator embedding a sense transistor directly into the resonator body. Combining the benefits of FET sensing with the frequency scaling capabilities and high quality factors (Q) of internal dielectrically transduced bar resonators, the resonant body transistor achieves >10 GHz frequencies and can be integrated into a standard CMOS process for on-chip clock generation, high-Q microwave circuits, fundamental quantum-state preparation and observation, and high-sensitivity measurements. An 11.7 GHz bulk-mode RBT is demonstrated with a quality factor Q of 1830, marking the highest frequency acoustic resonance measured to date on a silicon wafer. PMID:20180594

Weinstein, Dana; Bhave, Sunil A

2010-04-14

120

Surface spin wave resonator  

Microsoft Academic Search

Consideration is given to the properties of a surface spin wave converter of meander type consisting of a YIG film deposited on a single-crystal ferrite substrate. The impedance of the device is determined, and the resonant frequency and q-factor of a resonator based on such a converter are evaluated. Results are presented for a YIG\\/ferrite resonator whose q-factor is of

G. A. Vugalter

1980-01-01

121

Dynamically generated hadron resonances  

SciTech Connect

As an example of dynamically generated resonances we mention the interaction of vector mesons with baryons within the local hidden gauge formalism which gives rise to a large amount of such states, many of which can be associated to known resonances, while others represent predictions for new resonances. The width of these states coming from decay into pseudoscalar baryon is also addressed. We also mention recent states coming from {rho}{pi} interaction obtained with Faddeev equations.

Oset, E.; Gonzalez, P. [Departamento de Fisica Teorica and IFIC, Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigacion de Paterna, Aptd. 22085, 46071 Valencia (Spain); Ramos, A. Torres [Departament d'Estructura i Constituents de la Materia, Universitat de Barcelona (Spain); Martinez, A. [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan); Garzon, E. J.; Xie, Ju Jun

2011-10-21

122

Resonant Optical Antennas  

Microsoft Academic Search

We have fabricated nanometer-scale gold dipole antennas designed to be resonant at optical frequencies. On resonance, strong field enhancement in the antenna feed gap leads to white-light supercontinuum generation. The antenna length at resonance is considerably shorter than one-half the wavelength of the incident light. This is in contradiction to classical antenna theory but in qualitative accordance with computer simulations

P. Mühlschlegel; H.-J. Eisler; O. J. F. Martin; B. Hecht; D. W. Pohl

2005-01-01

123

Adiabatic microring resonators.  

PubMed

A class of whispering-gallery-mode resonators, herein referred to as adiabatic microring resonators, is proposed and numerically demonstrated. Adiabatic microrings enable electrical and mechanical contact to be made to the resonator without inducing radiation, while supporting only a single radial mode and therein achieving an uncorrupted free spectral range (FSR). Rigorous finite-difference time-domain simulations indicate that adiabatic microrings with outer diameters as small as 4 ?m can achieve resonator quality factors (Qs) as high as Q = 88,000 and an FSR of 8.2 THz, despite large internal contacts. PMID:20890343

Watts, Michael R

2010-10-01

124

Ferromagnetic Resonance Force Microscopy  

Microsoft Academic Search

The magnetic resonance force microscope (MRFM) is a novel scanning probe instrument that combines the three-dimensional imaging\\u000a capabilities of magnetic resonance imaging (MRI) with the high sensitivity and resolution of atomic force microscopy (AFM).\\u000a In the nuclear magnetic resonance (NMR) mode or the electron spin resonance (ESR) mode it will enable nondestructive, chemical-specific,\\u000a high-resolution microscopic studies and imaging of subsurface properties of a broad range of

Philip E. Wigen; Michael L. Roukes; Peter C. Hammel

125

Giant resonance decay  

SciTech Connect

Decay studies of giant multipole resonances are discussed, emphasizing the role of Coulomb excitation with intermediate energy heavy ions, which can provide very large cross sections for both isoscalar and isovector resonances. We discuss measurement of the photon decay of one and two phonon giant resonances, reporting results where available. It is pointed out throughout the presentation that the use of E1 photons as a tag'' provides a means to observe weakly excited resonances that cannot be observed in the singles spectra. 30 refs., 16 figs., 1 tab.

Beene, J.R.; Bertrand, F.E.

1990-01-01

126

Localized ferromagnetic resonance force microscopy of permalloy-cobalt films  

SciTech Connect

We report the Ferromagnetic Resonance Force Microscopy (FMRFM) experiments on a combined permalloy-cobalt continuous film. Our studies demonstrate the capability of FMRFM to perform local spectroscopy of different ferromagnetic materials. Theoretical analysis of the uniform resonance mode at the edge of the film provides good quantitative agreement with the experimental data. Our experiments demonstrate the micron scale lateral resolution and allow to extract local magnetic properties in continuous ferromagnetic samples.

Nazaretski, Evgueni [Los Alamos National Laboratory; Movshovich, Roman [Los Alamos National Laboratory; Martin, Ivar [Los Alamos National Laboratory; Cha, Kitty V [Los Alamos National Laboratory; Akhadov, Elshan A [Los Alamos National Laboratory; Obukhov, Yu [OH STATE U; Pelekhov, D C [OH STATE U; Hammel, P C [OH STATE U

2008-01-01

127

Analysis of lasing in chemical oxygen-iodine lasers with unstable resonators using a geometric-optics model.  

PubMed

A simple geometric-optics model is developed that describes the power extraction in chemical oxygen-iodine lasers (COILs) with unstable resonators. The positive and negative branch unstable resonators with cylindrical mirrors that were recently used in COILs are studied theoretically. The optical extraction efficiency, spatial distributions of the intracavity radiation intensity in the flow direction, and the intensity in the far field are calculated for both kinds of resonator as a function of both the resonator and the COIL parameters. The optimal resonator magnifications that correspond to the maximum intensity in the far field are found. PMID:19412214

Barmashenko, Boris D

2009-05-01

128

Localized surface plasmon resonance biosensors.  

PubMed

In this review, the most recent progress in the development of noble metal nano-optical sensors based on localized surface plasmon resonance (LSPR) spectroscopy is summarized. The sensing principle relies on the LSPR spectral shifts caused by the surrounding dielectric environmental change in a binding event. Nanosphere lithography, an inexpensive and simple nanofabrication technique, has been used to fabricate the nanoparticles as the LSPR sensing platforms. As an example of the biosensing applications, the LSPR detection for a biomarker of Alzheimer's disease, amyloid-derived diffusable ligands, in human brain extract and cerebrospinal fluid samples is highlighted. Furthermore, the LSPR sensing method can be modified easily and used in a variety of applications. More specifically, a LSPR chip capable of multiplex sensing, a combined electrochemical and LSPR protocol and a fabrication method of solution-phase nanotriangles are presented here. PMID:17716111

Zhao, Jing; Zhang, Xiaoyu; Yonzon, Chanda Ranjit; Haes, Amanda J; Van Duyne, Richard P

2006-08-01

129

Magnetic resonance imaging and spectroscopy  

SciTech Connect

This book contains 17 selections. Some of the chapter titles are: Basic Principles of Magnetic Resonance Imaging;Evaluation of Demyelinating Diseases;Respiratory Gating in Magnetic Resonance Imaging;Magnetic Resonance Imaging of the Abdomen;Contrast Agents in Magnetic Resonance Imaging;and Economic Considerations in Magnetic Resonance Imaging.

Mettler, F.A.; Muroff, L.R.; Kulkarni, M.V.

1986-01-01

130

High-Q Bandpass Resonators Utilizing Bandstop Resonator Pairs.  

National Technical Information Service (NTIS)

A high-Q bandpass resonators utilizing composite bandstop resonator pairs is reported. The bandstop resonator pairs are formed of composite series or parallel connected realizable transmission line elements. The elements are exclusively either quarter-wav...

H. C. Okean

1973-01-01

131

Resonance seeking control  

Microsoft Academic Search

An adaptive control method that seeks the unknown resonant frequency of a load and drives it at its resonant frequency to achieve optimal performance is proposed and investigated. The method is based on estimating the derivative of the average power delivered to the load with respect to the driving frequency and using this estimate to adaptively control the driving frequency.

C. Gokcek

2005-01-01

132

The Concept of Resonance  

ERIC Educational Resources Information Center

|A general example of a delocalization system associated with a higher energy than the localized one, which suggests that it is wrong to consider delocalization as equivalent to resonance stabilization, is presented. The meaning of resonance energy as it appears in valence bond theory is described as the lowering of the calculated ground-state…

Truhlar, Donald G.

2007-01-01

133

Adaptive resonance associative map  

Microsoft Academic Search

This article introduces a neural architecture termed Adaptive Resonance Associative Map ( ARAM) that extends unsupervised Adaptive Resonance Theory (ART) systems for rapid, yet stable, heteroassociative learning. ARAM can be visualized as two overlapping ART networks sharing a single category field. Although ARAM is simpler in architecture than another class of supervised ART models known as ARTMAP, it produces classification

Ah-hwee Tan

1995-01-01

134

Supervised adaptive resonance networks  

Microsoft Academic Search

Adaptive Resonance Theory (ART) has been used to design a number of massively-parallel, unsupervised, pattern recognition machines. ART networks learn a set of recognition codes by ensuring that input vectors match or resonate with one of a learned set of template vectors. A novelty detector determines whether or not an input vector is new or familiar. Novel input vectors lead

Robert A. Baxter

1991-01-01

135

Mesonic content of the nucleon and the Roper resonance  

NASA Astrophysics Data System (ADS)

We investigate colorless (mesonic) 3q-qq¯ components in the nucleon and the Roper resonance N*(1440). Starting from constituent quarks and gluons we estimate the excitation of qq¯ pairs in a gluon exchange model with the strong coupling constant extracted from a comparison with a nonperturbative resonating group calculation of the ?,?,?, and ? content of the nucleon. Applying the same model to the Roper resonance, we find as the most striking result a very strong scalar-isoscalar ?-content of the N*(1440) with a strength of the 3q-qq¯ configurations comparable to the 3q component itself.

Dillig, M.; Schott, M.

2007-06-01

136

Thermoacoustic resonance effect and circuit modelling of biological tissue  

NASA Astrophysics Data System (ADS)

In this letter, thermoacoustic resonance effect is predicted from theoretical analysis with series resistor-inductor-capacitor resonance circuit model and then observed experimentally using muscle tissue illuminated by multi-pulse microwave source. Through model fitting, the circuit parameters are extracted to characterize quantitatively the resonant response of the tissue. Coherent demodulation is applied to obtain the enhanced signal-to-noise ratio and spatial information by treating tissue as a communication channel. This physical phenomenon shows significantly higher sensitivity than conventional single microwave pulse induced thermoacoustic effect, enabling the potential design of low-power thermoacoustic imaging device for portable and on-site diagnosis.

Gao, Fei; Zheng, Yuanjin; Feng, Xiaohua; Ohl, Claus-Dieter

2013-02-01

137

Resonant snubber inverter  

DOEpatents

A resonant, snubber-based, soft switching, inverter circuit achieves lossless switching during dc-to-ac power conversion and power conditioning with minimum component count and size. Current is supplied to the resonant snubber branches solely by the main inverter switches. Component count and size are reduced by use of a single semiconductor switch in the resonant snubber branches. Component count is also reduced by maximizing the use of stray capacitances of the main switches as parallel resonant capacitors. Resonance charging and discharging of the parallel capacitances allows lossless, zero voltage switching. In one embodiment, circuit component size and count are minimized while achieving lossless, zero voltage switching within a three-phase inverter.

Lai, Jih-Sheng (Knoxville, TN); Young, Sr., Robert W. (Oak Ridge, TN); Chen, Daoshen (Knoxville, TN); Scudiere, Matthew B. (Oak Ridge, TN); Ott, Jr., George W. (Knoxville, TN); White, Clifford P. (Knoxville, TN); McKeever, John W. (Oak Ridge, TN)

1997-01-01

138

Resonant snubber inverter  

DOEpatents

A resonant, snubber-based, soft switching, inverter circuit achieves lossless switching during dc-to-ac power conversion and power conditioning with minimum component count and size. Current is supplied to the resonant snubber branches solely by the main inverter switches. Component count and size are reduced by use of a single semiconductor switch in the resonant snubber branches. Component count is also reduced by maximizing the use of stray capacitances of the main switches as parallel resonant capacitors. Resonance charging and discharging of the parallel capacitances allows lossless, zero voltage switching. In one embodiment, circuit component size and count are minimized while achieving lossless, zero voltage switching within a three-phase inverter. 14 figs.

Lai, J.S.; Young, R.W. Sr.; Chen, D.; Scudiere, M.B.; Ott, G.W. Jr.; White, C.P.; McKeever, J.W.

1997-06-24

139

Polarization Near Isobaric Analogue Resonances.  

National Technical Information Service (NTIS)

For the purpose of analysing isobaric analogue resonances, a single-level resonance formula has been incorporated into nuclear scattering amplitudes found with an optical-model potential. The inclusion of the resonance term leads to polarization magnitude...

J. L. Adams W. J. Thompson D. Robson

1966-01-01

140

LABCOM resonator Phase 3  

SciTech Connect

The purpose of this project was to develop quartz crystal resonator designs, production processes, and test capabilities for 5-MHz, 6.2-MHz, and 10-MHz resonators for Tactical Miniature Crystal Oscillator (TMXO) applications. GE Neutron Devices (GEND) established and demonstrated the capability to produce and test quartz crystal resonators for use in the TMXO developed by the US Army ERADCOM (now LABCOM). The goals in this project were based on the ERADCOM statement of work. The scope of work indicated that the resonator production facilities for this project would not be completely independent, but that they would be supported in part by equipment and processes in place at GEND used in US Department of Energy (DOE) work. In addition, provisions for production test equipment or or eventual technology transfer costs to a commercial supplier were clearly excluded from the scope of work. The demonstrated technical capability of the deep-etched blank design is feasible and practical. It can be manufactured in quantity with reasonable yield, and its performance is readily predictable. The ceramic flatpack is a very strong package with excellent hermeticity. The four-point mount supports the crystal to reasonable shock levels and does not perturb the resonator's natural frequency-temperature behavior. The package can be sealed with excellent yields. The high-temperature, high-vacuum processing developed for the TMXO resonator, including bonding the piezoid to its mount with conductive polyimide adhesive, is consistent with precision resonator fabrication. 1 fig., 6 tabs.

Keres, L.J.

1990-11-01

141

Modelling resonant planetary systems  

NASA Astrophysics Data System (ADS)

Many discovered multi-planet systems are in meanmotion resonances. The aim of this work is to study dynamical processes leading to the formation of resonant configurations on the basis of a unified model described earlier [1]. The model includes gravitational interactions of planets and migration of planets due to the presence of a gas disc. For the observed systems 24 Sex, HD 37124, HD 73526, HD 82943, HD 128311, HD 160691, Kepler 9, NN Ser with planets moving in the 2:1 resonance, it is shown that the capture in this resonance occurs at very wide ranges of parameters of both type I and type II migration. Conditions of migration leading to the formation of the resonant systems HD 45364 ? HD 200964 (3:2 and 4:3, respectively) are obtained. Formation scenarios are studied for the systems HD 102272, HD 108874, HD 181433, HD 202206 with planets in high order resonances. We discuss also how gravitational interactions of planets and planetesimal discs lead to the breakup of resonant configurations and the formation of systems similar to the 47 UMa system.

Emel'yanenko, V.

2012-09-01

142

Unfolding the Second Riemann sheet with Pade Approximants: hunting resonance poles  

SciTech Connect

Based on Pade Theory, a new procedure for extracting the pole mass and width of resonances is proposed. The method is systematic and provides a model-independent treatment for the prediction and the errors of the approximation.

Masjuan, Pere [Faculty of Physics, University of Vienna. Boltzmanngasse 5, A-1090 Wien (Austria); Departamento de Fisica Teorica y del Cosmos, Universidad de Granada, Campus de Fuentenueva, E-18071 Granada (Spain)

2011-05-23

143

Atomic pseudospin resonance.  

PubMed

A new type of resonance is discovered in Rydberg atoms placed in a constant magnetic field -->B and a transient electric field that rotates at the constant frequency -->omega in a plane perpendicular to -->B. The dynamics is explained in terms of two pseudoparticles with spin 1 / 2 in two generalized magnetic fields. The resonance frequency is predicted and found at -->omega = (e/2m)-->B, where -e/m is the electron's charge-to-(reduced)mass ratio. We discuss the applicability of the resonance to accurate magnetic field measurements and the prospects for determining e/m with improved precision. PMID:11736397

Fregenal, D; Ehrenreich, T; Henningsen, B; Horsdal-Pedersen, E; Nyvang, L; Ostrovsky, V N

2001-11-09

144

Spin resonance strength calculations  

SciTech Connect

In calculating the strengths of depolarizing resonances it may be convenient to reformulate the equations of spin motion in a coordinate system based on the actual trajectory of the particle, as introduced by Kondratenko, rather than the conventional one based on a reference orbit. It is shown that resonance strengths calculated by the conventional and the revised formalisms are identical. Resonances induced by radiofrequency dipoles or solenoids are also treated; with rf dipoles it is essential to consider not only the direct effect of the dipole but also the contribution from oscillations induced by it.

Courant,E.D.

2008-10-06

145

Materials for Bulk Acoustic Resonators and Filters  

NASA Astrophysics Data System (ADS)

Highly selective solidly mounted bulk acoustic wave (BAW) band pass filters are suited for mobile and wireless systems in the GHz frequency range between 0.8 and 10 GHz. Electro-acoustic thin film BAW resonators are the building blocks these BAW filters. Piezoelectric materials used in these resonators include mainly AlN or ZnO which can be deposited by dedicated thin film sputter deposition techniques. Using these piezo-electric materials and using suited materials for the acoustic Bragg reflector, BAW resonators with high quality factors can be fabricated. The achievable filter bandwidth is approximately 4Alternatively, also ferroelectric thin films might be used to achieve higher coupling coefficient and thus filter bandwidth. BAW resonators and filters have been designed and fabricated on 6" Silicon and glass wafers. Results are presented for resonators and filters operating between 1.95 and 8 GHz. The talk will give an overview of the material aspects which are important for BAW devices. It will be shown that modeling of the resonator and filter response using 1D electro-acoustic simulation (1,2) which includes losses is essential to extract acoustic and electrical material parameters. (1) Solidly Mounted Bulk Acoustic Wave Filters for the Ghz Frequency Range, H.P. Loebl, C. Metzmacher , D.N.Peligrad , R. Mauczok , M. Klee , W. Brand , R.F. Milsom , P.Lok , F.van Straten , A. Tuinhout , J.W.Lobeek, IEEE 2002 Ultrasonics Symposium Munich, October 2002. (2) Combined Acoustic-Electromagnetic Simulation Of Thin-Film Bulk Acoustic Wave Filters, R.F. Milsom, H-P. Löbl, D.N. Peligrad, J-W. Lobeek, A. Tuinhout, R. H. ten Dolle IEEE 2002 Ultrasonics Symposium Munich, October 2002.

Loebl, Hans-Peter

2003-03-01

146

Simple Microwave Resonance Spectrometer  

Microsoft Academic Search

A relatively simple and inexpensive apparatus for the observation of electron paramagnetic resonance at microwave frequencies is described. The apparatus is designed for the undergraduate laboratory but, with some modification, may be used as a research tool.

E. S. Gravlin; J. A. Cowen

1959-01-01

147

Magnetic resonance imaging  

SciTech Connect

This book contains the following four major sections: physics and chemistry, relaxation/relaxometry, instrumentation, research areas. The authors discuss instrumentation and technical approaches in magnetic resonance (MR) imaging.

Partain, C.L.; Price, R.R.; Patton, J.A.; Kulkarni, M.V.; James, A.E.

1988-01-01

148

Magnetic Resonance Imaging (MRI).  

National Technical Information Service (NTIS)

Magnetic resonance imaging (MRI) is a method of graphically representing the distribution of water and other hydrogen-rich molecules in the human body. Imaging parameters are complex. Although MR images may demonstrate anatomy as do conventional radiograp...

E. Feigenbaum

1985-01-01

149

Micro-machined resonator  

DOEpatents

A micro-machined resonator, typically quartz, with upper and lower micro-machinable support members, or covers, having etched wells which may be lined with conductive electrode material, between the support members is a quartz resonator having an energy trapping quartz mesa capacitively coupled to the electrode through a diaphragm; the quartz resonator is supported by either micro-machined cantilever springs or by thin layers extending over the surfaces of the support. If the diaphragm is rigid, clock applications are available, and if the diaphragm is resilient, then transducer applications can be achieved. Either the thin support layers or the conductive electrode material can be integral with the diaphragm. In any event, the covers are bonded to form a hermetic seal and the interior volume may be filled with a gas or may be evacuated. In addition, one or both of the covers may include oscillator and interface circuitry for the resonator.

Godshall, N.A.; Koehler, D.R.; Liang, A.Y.; Smith, B.K.

1993-03-30

150

Cyclotron resonance and quasiparticles  

SciTech Connect

This introductory paper contains personal perspectives about the importance of cyclotron resonance in forming our modern view of solids. The papers following this one will discuss the discovery, refinements, and some of the latest developments. Although I will touch on some of these subjects, I leave the details to the other authors and in the main focus on the conceptual impact of the work. I propose that it was experiments based on cyclotron resonance which established the quasiparticle concept.

Cohen, Marvin L.

2005-01-15

151

Atomic resonance and scattering  

SciTech Connect

Experiments were conducted in the following areas: mapping of energy levels of a Rydberg lithium atom in a strong magnetic field in the vicinity of a crossing between levels from different principle quantum numbers, electrodynamics in a cavity, resonance enhanced multiphoton ionization, velocity dependence of rotational rainbow structure in Na2-Ar, high precision mass measurement on single ions using cyclotron resonance, low temperature energy transfer, trapping of neutral atoms, and vibrationally inelastic collisions.

Kleppner, D.; Pritchard, D.E.; Ahmad-Bitar, R.; Ducas, T.; Kelleher, D.; Ligare, M.; Lyyra, A.M.; Moskowitz, P.; Saenger, K.L.; Smith, N.

1984-01-01

152

resonant Auger decay  

Microsoft Academic Search

The Ar resonant Auger spectra have been recorded in Raman conditions at a photon energy of 249 eV corresponding to the Ar 2p1\\/2 ? 3d excitation. The high experimental resolution allowed us to resolve the fine structure in the resonant Auger spectra in much greater detail than obtained previously. Experimental individual angular anisotropy ? parameter values of the Ar 2p?1

S Osmekhin; S Fritzsche; A N Grum-Grzhimailo; H Aksela; S Aksela

153

Nuclear magnetic resonance gyroscope  

SciTech Connect

A nuclear magnetic resonance gyro using two nuclear magnetic resonance gases, preferably xenon 129 and xenon 131, together with two alkaline metal vapors, preferably rubidium, potassium or cesium, one of the two alkaline metal vapors being pumped by light which has the wavelength of that alkaline metal vapor, and the other alkaline vapor being illuminated by light which has the wavelength of that other alkaline vapor.

Grover, B.C.

1984-02-07

154

Neutral Pion Electroproduction in the Delta Resonance Region  

SciTech Connect

The electroproduction of baryon resonances at high Q2 is examined. Analysis focuses on the Delta(1232) resonance via exclusive pseudoscalar meson production of À0 particles. Differential cross sections are extracted for exclusive À0 electroproduction. In the central invariant mass (W) region the cross sections are used to extract resonant multipole amplitudes. In particular, the ratio of the electric quadrupole to magnetic dipole amplitudes (E2/M1) will be discussed for the Delta(1232) resonance. The transition to pQCD is discussed in terms of E2/M1 and other multipoles. The helicity amplitude A3/2 can be used as a baryon helicity conservation meter in this context and will be discussed. The fast shrinking of the resonant contribution in the Delta region is observed at this high momentum transfer. Apart from the observables related to pQCD scaling, the transition form factor G#23;M is extracted along with the scalar to magnetic dipole ratio C2/M1.

Anthony Villano

2007-11-01

155

Resonant nonlinear ultrasound spectroscopy  

DOEpatents

Components with defects are identified from the response to strains applied at acoustic and ultrasound frequencies. The relative resonance frequency shift .vertline..DELTA..function./.function..sub.0.vertline., is determined as a function of applied strain amplitude for an acceptable component, where .function..sub.0 is the frequency of the resonance peak at the lowest amplitude of applied strain and .DELTA..function. is the frequency shift of the resonance peak of a selected mode to determine a reference relationship. Then, the relative resonance frequency shift .vertline..DELTA..function./.function..sub.0 is determined as a function of applied strain for a component under test, where fo .function..sub.0 the frequency of the resonance peak at the lowest amplitude of applied strain and .DELTA..function. is the frequency shift of the resonance peak to determine a quality test relationship. The reference relationship is compared with the quality test relationship to determine the presence of defects in the component under test.

Johnson, Paul A. (Santa Fe, NM); TenCate, James A. (Los Alamos, NM); Guyer, Robert A. (Amherst, MA); Van Den Abeele, Koen E. A. (Sint-Niklaas, BE)

2001-01-01

156

Resonantly driven wobbling kinks.  

PubMed

The amplitude of oscillations of the freely wobbling kink in the varphi(4) theory decays due to the emission of second-harmonic radiation. We study the compensation of these radiation losses (as well as additional dissipative losses) by the resonant driving of the kink. We consider both direct and parametric driving at a range of resonance frequencies. In each case, we derive the amplitude equations which describe the evolution of the amplitude of the wobbling and the kink's velocity. These equations predict multistability and hysteretic transitions in the wobbling amplitude for each driving frequency--the conclusion verified by numerical simulations of the full partial differential equation. We show that the strongest parametric resonance occurs when the driving frequency equals the natural wobbling frequency and not double that value. For direct driving, the strongest resonance is at half the natural frequency, but there is also a weaker resonance when the driving frequency equals the natural wobbling frequency itself. We show that this resonance is accompanied by the translational motion of the kink. PMID:19792274

Oxtoby, O F; Barashenkov, I V

2009-08-31

157

Resonance-assisted decay of nondispersive wave packets.  

PubMed

We present a quantitative semiclassical theory for the decay of nondispersive electronic wave packets in driven, ionizing Rydberg systems. Statistically robust quantities are extracted combining resonance-assisted tunneling with subsequent transport across chaotic phase space and a final ionization step. PMID:16907569

Wimberger, Sandro; Schlagheck, Peter; Eltschka, Christopher; Buchleitner, Andreas

2006-07-25

158

NUCLEAR MAGNETIC RESONANCE SPECTRA OF TWO TYPES OF LIGNIN  

Technology Transfer Automated Retrieval System (TEKTRAN)

Lignin content can be useful to estimate fiber digestion of forage plants. Quantitative determination of lignin by the spectrophotometric method presumes an efficient standard. The objective of this work was to evaluate, by the nuclear magnetic resonance (NMR), two lignins, one extracted with acetyl...

159

Schumann Resonances in Lightning Research  

Microsoft Academic Search

Schumann resonances (SR) are global electromagnetic resonances excited primarily by lightning discharges. This review is aimed at the reader generally unfamiliar with Schumann resonances. Our goal is to give some historical context to SR research, and to show the extensive use of Schumann resonances in a variety of lightning-related studies in recent years, ranging from estimates of the spatial and

Colin Price; Olga Pechony; Eran Greenberg

2007-01-01

160

RF voltage modulation at discrete frequencies with applications to crystal channeling extraction  

SciTech Connect

RF voltage modulation at a finite number of discrete frequencies is described in a Hamiltonian resonance framework. The theory is applied to the problem of parasitic extraction of a fixed target beam from a high energy proton collider, using a bent crystal as a thin ``septum`` within an effective width of about one micron. Three modes of employment of discrete resonances are proposed.First, a single relatively strong static ``drive`` resonance may be used to excite a test proton so that it will penetrate deeply into the channeling crystal. Second, a moderately strong ``feed`` resonance with a ramped modulation tune may be used to adiabatically trap protons near the edge of the beam core, and transport them to the drive resonance. Third, several weak resonances may be overlapped to create a chaotic amplitude band, either to transport protons to the drive resonance, or to provide a ``pulse stretching`` buffer between a feed resonance and the drive resonance. Extraction efficiency is semi- quantitatively described in terms of characteristic ``penetration,`` ``depletion,`` and ``repetition`` times. simulations are used to quantitatively confirm the fundamental results of the theory, and to show that a prototypical extraction scheme using all three modes promises good extraction performance.

Gabella, W.; Rosenzweig, J. [California Univ., Los Angeles, CA (United States). Dept. of Physics; Kick, R. [Illinois Math and Science Academy, Aurora, Illinois (United States); Peggs, S. [Fermi National Accelerator Lab., Batavia, IL (United States)

1992-05-01

161

RF voltage modulation at discrete frequencies with applications to crystal channeling extraction  

SciTech Connect

RF voltage modulation at a finite number of discrete frequencies is described in a Hamiltonian resonance framework. The theory is applied to the problem of parasitic extraction of a fixed target beam from a high energy proton collider, using a bent crystal as a thin septum'' within an effective width of about one micron. Three modes of employment of discrete resonances are proposed.First, a single relatively strong static drive'' resonance may be used to excite a test proton so that it will penetrate deeply into the channeling crystal. Second, a moderately strong feed'' resonance with a ramped modulation tune may be used to adiabatically trap protons near the edge of the beam core, and transport them to the drive resonance. Third, several weak resonances may be overlapped to create a chaotic amplitude band, either to transport protons to the drive resonance, or to provide a pulse stretching'' buffer between a feed resonance and the drive resonance. Extraction efficiency is semi- quantitatively described in terms of characteristic penetration,'' depletion,'' and repetition'' times. simulations are used to quantitatively confirm the fundamental results of the theory, and to show that a prototypical extraction scheme using all three modes promises good extraction performance.

Gabella, W.; Rosenzweig, J. (California Univ., Los Angeles, CA (United States). Dept. of Physics); Kick, R. (Illinois Math and Science Academy, Aurora, Illinois (United States)); Peggs, S. (Fermi National Accelerator Lab., Batavia, IL (United States))

1992-05-01

162

Time scales in nuclear giant resonances  

SciTech Connect

We propose a general approach to characterise fluctuations of measured cross sections of nuclear giant resonances. Simulated cross sections are obtained from a particular, yet representative, self-energy that contains all information about fragmentations. Using a wavelet analysis, we demonstrate the extraction of time scales of cascading decays into configurations of different complexity of the resonance. We argue that the spreading widths of collective excitations in nuclei are determined by the number of fragmentations as seen in the power spectrum. An analytic treatment of the wavelet analysis using a Fourier expansion of the cross section confirms this principle. A simple rule for the relative lifetimes of states associated with hierarchies of different complexity is given.

Heiss, W. D. [National Institute for Theoretical Physics, Stellenbosch Institute for Advanced Study, and Institute of Theoretical Physics, University of Stellenbosch, 7602 Matieland (South Africa); Nazmitdinov, R. G. [Department de Fisica, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain); Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, RU-141980 Dubna (Russian Federation); Smit, F. D. [iThemba LABS, Post Office Box 722, Somerset West 7129 (South Africa)

2010-03-15

163

The market for magnetic resonance spectroscopy  

SciTech Connect

The medical market is, at present, the most dominant market for low T{sub c} superconductors. Indeed, without magnetic resonance imaging (MRI), there would hardly be a low T{sub c} superconductor market at all. According to the author, any development that can expand the medical market for MRI machines would be a welcome one. This paper reports how the recent advances in magnetic resonance spectroscopy (MRS) are such a development. While the principle of MRS has bee around as long as MRI, only recently have advances in technique, computer programming and magnet technology allowed MRS to advance to a point where it may become an important technology-one that could increase the medical market for superconductors. The author discussed how MRS can be used to analyze oil core samples for their oil content, oil/water ratios, how the oil is bound and how to extract it.

Carlson, L.

1990-01-01

164

Resonance decay effects on anisotropy parameters  

SciTech Connect

We present the elliptic flow v{sub 2} of pions produced from resonance decays. The transverse momentum p{sub T} spectra of the parent particles are taken from thermal model fits and their v{sub 2} are fit under the assumption that they follow a number-of-constituent-quark (NCQ) scaling law expected from quark-coalescence models. The v{sub 2} of pions from resonance particle decays is found to be similar to the measured pion v{sub 2}. We also propose the measurement of electron v{sub 2} as a means to extract open-charm v{sub 2} and investigate whether a thermalized system of quasi-free quarks and gluons (a quark-gluon plasma) is created in collisions of Au nuclei at RHIC.

Dong, Xin; Esumi, S.; Sorensen, P.; Xu, Nu; Xu, Z.

2004-03-11

165

Capture probabilities for secondary resonances  

NASA Astrophysics Data System (ADS)

The tidal evolutions of Miranda and Umbriel in the 1:3, i-squaredM resonance are presently addressed via analyses of the role of secondary resonances during tidal evolution within a j:j+2 orbit-orbit resonance. The results thus obtained allow both analytical and numerical refinement of Malhotra's (1990) results for the probability of capture into secondary resonances. Attention is given to Miranda's evolution in the case of capture into the 3/1 secondary resonance.

Henrard, Jacques; Moons, Michele

1992-02-01

166

Not-so-resonant, resonant absorption  

SciTech Connect

When an intense electromagnetic wave is incident obliquely on a sharply bounded overdense plasma, strong energy absorption can be accounted for by the electrons that are dragged into the vacuum and sent back into the plasma with velocities vapprox. =v/sub osc/. This mechanism is more efficient than usual resonant absorption for v/sub osc//..omega..>L, with L being the density gradient length. In the very high-intensity CO/sub 2/-laser--target interaction, this mechanism may account for most of the energy absorption.

Brunel, F.

1987-07-06

167

Magnetostatic micro-resonators.  

NASA Astrophysics Data System (ADS)

Small scale magnetostatic wave devices are potentially important for on-chip filters for communication systems and more exotic gated spin wave devices. We describe experimental results that measure transmission and reflection resonances in micron size resonators coupled to coplanar waveguides. Ferromagnetic CoZrTa films were sputtered onto Si wafers covered by SiO2 and lithographically patterned into stripes and crosses of varying length and width. Magnetostatic waves were excited and detected by overlaying coupling loops patterned as shorted coplanar waveguides. Transmission and reflection S-parameters of fabricated structures were measured in the frequency range (0-50)GHz. Transmission and reflection resonances strongly dependent on the geometry of the ferromagnetic device and applied magnetic field are observed. The results are modeled as standing magneto static waves in micro-resonators. We discuss effect of biasing magnetic fields, approaches to enhanced coupling to the magnetostatic resonators, magnetostatic wave interferometers and magnetization controlled magnetostatic wave switching in junctions. This work is supported by the Nanoelectronics Research Initiative (NRI) - Western Institute of Nanoelectronics (WIN)

Kozhanov, Alexander; Griffith, Zach; Rodwell, Mark; Allen, Jim; Lee, Dok Won; Wang, Shan; Jacob, Ajey

2008-03-01

168

Resonant ultrasound spectrometer  

DOEpatents

An ultrasound resonant spectrometer determines the resonant frequency spectrum of a rectangular parallelepiped sample of a high dissipation material over an expected resonant response frequency range. A sample holder structure grips corners of the sample between piezoelectric drive and receive transducers. Each transducer is mounted on a membrane for only weakly coupling the transducer to the holder structure and operatively contacts a material effective to remove system resonant responses at the transducer from the expected response range. i.e., either a material such as diamond to move the response frequencies above the range or a damping powder to preclude response within the range. A square-law detector amplifier receives the response signal and retransmits the signal on an isolated shield of connecting cabling to remove cabling capacitive effects. The amplifier also provides a substantially frequency independently voltage divider with the receive transducer. The spectrometer is extremely sensitive to enable low amplitude resonance to be detected for use in calculating the elastic constants of the high dissipation sample.

Migliori, Albert (Santa Fe, NM); Visscher, William M. (Los Alamos, NM); Fisk, Zachary (Santa Fe, NM)

1990-01-01

169

MACHINERY RESONANCE AND DRILLING  

SciTech Connect

New developments in vibration analysis better explain machinery resonance, through an example of drill bit chattering during machining of rusted steel. The vibration of an operating drill motor was measured, the natural frequency of an attached spring was measured, and the two frequencies were compared to show that the system was resonant. For resonance to occur, one of the natural frequencies of a structural component must be excited by a cyclic force of the same frequency. In this case, the frequency of drill bit chattering due to motor rotation equaled the spring frequency (cycles per second), and the system was unstable. A soft rust coating on the steel to be drilled permitted chattering to start at the drill bit tip, and the bit oscillated on and off of the surface, which increased the wear rate of the drill bit. This resonant condition is typically referred to as a motor critical speed. The analysis presented here quantifies the vibration associated with this particular critical speed problem, using novel techniques to describe resonance.

Leishear, R.; Fowley, M.

2010-01-23

170

Electroproduction of the {Delta}(1232) Resonance at High Momentum Transfer  

SciTech Connect

We studied the electroproduction of the {Delta}(1232) resonance via the reaction p(e,thinspe{sup {prime}}p){pi}{sup 0} at four-momentum transfers Q{sup 2}=2.8 and 4.0 GeV{sup 2} . This is the highest Q{sup 2} for which exclusive resonance electroproduction has ever been observed. Decay angular distributions for {Delta}{r_arrow}p{pi}{sup 0} were measured over a wide range of barycentric energies covering the resonance. The N{endash}{Delta} transition form factor G{sup {asterisk}}{sub M} and ratios of resonant multipoles E{sub 1+}/M{sub 1+} and S{sub 1+}/M{sub 1+} were extracted from the decay angular distributions. These ratios remain small, indicating that perturbative QCD is not applicable for this reaction at these momentum transfers. {copyright} {ital 1998} {ital The American Physical Society }

Frolov, V.V.; Adams, G.S.; Davidson, R.M.; Klusman, M.; Mukhopadhyay, N.C.; Napolitano, J.; Nozar, M.; Price, J.W.; Stoler, P.; Witkowski, M. [Physics Department, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Bosted, P. [Physics Department, American University, Washington, D.C. 20016 (United States); Armstrong, C.S.; Meekins, D. [Department of Physics, College of William Mary, Williamsburg, Virginia 23187 (United States); Assamagan, K.; Avery, S.; Baker, O.K.; Eden, T.; Gaskell, D.; Gueye, P.; Hinton, W.; Keppel, C.; Madey, R.; Niculescu, G.; Niculescu, I.; Tang, L. [Physics Department, Hampton University, Hampton, Virginia 23668 (United States); Ahmidouch, A.; Madey, R. [Physics Department, Kent State University, Kent, Ohio 44242 (United States); Kim, W. [Physics Department, Kyungpook National University, Taegu, South (Korea); Baker, O.K.; Burkert, V.; Carlini, R.; Dunne, J.; Ent, R.; Keppel, C.; Mack, D.; Mitchell, J.; Tang, L.; Wood, S. [Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States); Koltenuk, D. [Physics Department, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States); Minehart, R. [Physics Department, University of Virginia, Charlottesville, Virginia 22903 (United States); Mkrtchyan, H.; Tadevosian, V. [Yerevan Physics Institute, Yerevan (Armenia)

1999-01-01

171

Feshbach resonance cooling of trapped atom pairs  

SciTech Connect

Spectroscopic studies of few-body systems at ultracold temperatures provide valuable information that often cannot be extracted in a hot environment. Considering a pair of atoms, we propose a cooling mechanism that makes use of a scattering Feshbach resonance. Application of a series of time-dependent magnetic field ramps results in either zero, one, or two atoms remaining trapped. If two atoms remain in the trap after the field ramps are completed, then they have been cooled. Application of the proposed cooling mechanism to optical traps or lattices is considered.

Dunn, Josh W.; Borca, Bogdan; Greene, Chris H. [Department of Physics and JILA, University of Colorado, Boulder, Colorado 80309-0440 (United States); Blume, D. [Department of Physics, Washington State University, Pullman, Washington 99164-2814 (United States); Granger, B.E. [Department of Physics, Santa Clara University, Santa Clara, California 95053 (United States)

2005-03-01

172

Nanowire Plasmon Resonators  

NASA Astrophysics Data System (ADS)

Strong interactions between light and matter can be engineered by confining light to a small volume for an extended period of time. Nanoscale plasmonic structures can concentrate lighte well below the diffraction limit, but realization of small mode-volume plasmon cavities remains an outstanding challenge. We propose and demonstrate a new approach for realization of nanoscale plasmon resonators enabling strong light-matter interaction. In our approach, chemically synthesized silver nanowires are surrounded by patterned dielectric to create resonators with mode volumes that are two orders of magnitude below the diffraction limit and quality factors approaching 100. We show that they can be used to enhance spontaneous emission rates of CdSe quantum dots and single diamond nitrogen-vacancy centers by a factor larger than 20 at the cavity resonance.

de Leon, Nathalie; Shields, Brendan; Yu, Chun; Englund, Dirk; Akimov, Alexey; Lukin, Mikhail; Park, Hongkun

2011-06-01

173

Magnetostrictive resonance excitation  

DOEpatents

The resonance frequency spectrum of a magnetostrictive sample is remotely determined by exciting the magnetostrictive property with an oscillating magnetic field. The permeability of a magnetostrictive material and concomitant coupling with a detection coil varies with the strain in the material whereby resonance responses of the sample can be readily detected. A suitable sample may be a magnetostrictive material or some other material having at least one side coated with a magnetostrictive material. When the sample is a suitable shape, i.e., a cube, rectangular parallelepiped, solid sphere or spherical shell, the elastic moduli or the material can be analytically determined from the measured resonance frequency spectrum. No mechanical transducers are required and the sample excitation is obtained without contact with the sample, leading to highly reproducible results and a measurement capability over a wide temperature range, e.g. from liquid nitrogen temperature to the Curie temperature of the magnetostrictive material.

Schwarz, Ricardo B. (Los Alamos, NM); Kuokkala, Veli-Tapani (Tampere, FI)

1992-01-01

174

The symmetric parabolic resonance  

NASA Astrophysics Data System (ADS)

The parabolic resonance instability emerges in diverse applications ranging from optical systems to simple mechanical ones. It appears persistently in p-parameter families of near-integrable Hamiltonian systems with n degrees of freedom provided n + p >= 3. Here we study the simplest (n = 2, p = 1) symmetric case. The structure and the phase-space volume of the corresponding instability zones are characterized. It is shown that the symmetric case has six distinct non-degenerate normal forms, and two degenerate ones. In the regular cases, the instability zone has the usual O(\\sqrt{\\varepsilon}) extent in the action direction. However, the phase-space volume of this zone is found to be polynomial in the perturbation parameter ? (and not exponentially small as in the elliptic resonance case). Finally, the extent of the instability zone in some of the degenerate cases is explored. Three applications in which the symmetric parabolic resonance arises are presented and analysed.

Rom-Kedar, V.; Turaev, D.

2010-06-01

175

Thin film resonator technology.  

PubMed

Advances in wireless systems have placed increased demands on high performance frequency control devices for operation into the microwave range. With spectrum crowding, high bandwidth requirements, miniaturization, and low cost requirements as a background, the thin film resonator technology has evolved into the mainstream of applications. This technology has been under development for over 40 years in one form or another, but it required significant advances in integrated circuit processing to reach microwave frequencies and practical manufacturing for high-volume applications. This paper will survey the development of the thin film resonator technology and describe the core elements that give rise to resonators and filters for today's high performance wireless applications. PMID:16048174

Lakin, Kenneth M

2005-05-01

176

Electrostatic (plasmon) resonances in nanoparticles  

NASA Astrophysics Data System (ADS)

A surface integral eigenvalue based technique for the direct calculation of resonance values of the permittivity of nanoparticles, and hence resonance frequencies, is discussed. General physical properties of electrostatic (plasmon) resonances are presented. Strong orthogonality properties of resonance modes, a two-dimensional phenomenon of “twin” spectrum and explicit estimates of resonance frequencies in terms of geometrical characteristics of convex nanoparticles are reported. Second-order corrections for resonance values of the dielectric permittivity are derived. Tunability and optical controllability of plasmon resonances in semiconductor nanoparticles are discussed and, as a digression, a plausible plasmon resonance mechanism for nucleation and formation of ball lightning is outlined. An efficient numerical algorithm for the calculation of resonance frequencies is developed and illustrated by extensive computational results that are compared with theoretical results and available experimental data.

Mayergoyz, Isaak D.; Fredkin, Donald R.; Zhang, Zhenyu

2005-10-01

177

Hexagonal quartz resonator  

DOEpatents

A generally flat, relatively thin AT-cut piezoelectric resonator element structured to minimize the force-frequency effect when mounted and energized in a housing. The resonator is in the form of an equilateral hexagon with the X crystallographic axis of the crystal passing through one set of opposing corners with mounting being effected at an adjacent set of corners respectively [+-]60[degree] away from the X axis which thereby results in a substantially zero frequency shift of the operating frequency. 3 figs.

Peters, R.D.M.

1982-11-02

178

Resonantly overcoming metal opacity  

NASA Astrophysics Data System (ADS)

The near-perfect response of electrons in metals to low-frequency electromagnetic fields makes even a sub-skin-depth film almost completely opaque to microwave radiation. Here, it is experimentally demonstrated that by surrounding a ~60 nm aluminium film with an array of thin resonant cavities, over 35% of the microwave radiation incident can be transmitted over a discrete set of narrow bands. This represents an enhancement of ~1000 times over an isolated film and allows for a frequency selective screen with a thickness less than 1/70th of the operating wavelength that may be tuned through choice of resonant geometry.

Edmunds, J. D.; Lockyear, M. J.; Hibbins, A. P.; Sambles, J. R.; Youngs, I. J.

2013-01-01

179

(Resonance ionization spectroscopy)  

SciTech Connect

J. P. Young attended the Fifth International Symposium on Resonance Ionization Spectroscopy and presented an invited oral presentation on research he and coworkers had carried out in applying diode lasers to resonance ionization mass spectrometry. A summary of the conference is given along with an assessment of some of the presentations that the author found of interest. Young also visited Professor Marassi at the University of Camerino to present a seminar and discuss mutual interests in a new molten salt research project of the author. Some of the studies at Camerino are described. Ideas concerning the author's research that came from private discussions are also presented here.

Young, J.P.

1990-10-11

180

Physics of Sports: Resonances  

NASA Astrophysics Data System (ADS)

When force is applied by an athlete to sports equipment resonances can occur. Just a few examples are: the ringing of a spiked volleyball, the strumming of a golf club shaft during a swing, and multiple modes induced in an aluminum baseball bat when striking a ball. Resonances produce acoustic waves which, if conditions are favorable, can be detected off the playing field. This can provide a means to evaluate athletic performance during game conditions. Results are given from the use of a simple hand-held acoustic detector - by a spectator sitting in the stands - to determine how hard volleyballs were spiked during college and high school games.

Browning, David

2000-04-01

181

Method for resonant measurement  

DOEpatents

A method of measurement of objects to determine object flaws, Poisson`s ratio ({sigma}) and shear modulus ({mu}) is shown and described. First, the frequency for expected degenerate responses is determined for one or more input frequencies and then splitting of degenerate resonant modes are observed to identify the presence of flaws in the object. Poisson`s ratio and the shear modulus can be determined by identification of resonances dependent only on the shear modulus, and then using that shear modulus to find Poisson`s ratio using other modes dependent on both the shear modulus and Poisson`s ratio. 1 fig.

Rhodes, G.W.; Migliori, A.; Dixon, R.D.

1996-03-05

182

Inexpensive Resonance Analysis  

NASA Astrophysics Data System (ADS)

A Barton's Pendulums device is a great tool for teaching students about resonance.1 Such a setup typically has several pendulums attached to a single string or solid support, where each pendulum is excited at a single frequency. The excitation can be produced by a large pendulum mass or by a motor. If a pendulum has a natural frequency that closely matches the excitation frequency, it swings with a large amplitude; otherwise, it does not. While these visual demonstrations are helpful, resonance behavior can be even better understood by graphically displaying the responses of oscillators to different excitations.

Moran, Timothy J.; Hill, Bradford K.

2009-12-01

183

Recoil-induced Resonances as All-optical Switches  

NASA Astrophysics Data System (ADS)

We have measured recoil-induced resonances (RIR) [1,2] in our system of laser-cooled 85Rb atoms. Although this technique has been demonstrated to be useful for the purpose of extracting the cloud temperature [3], our aim was to demonstrate an all optical switch based on recoil-induced resonances. In addition to a very narrow ``free-space'' recoil-induced resonance of approximately 15 kHz, we also discovered a much broader resonance (˜30 MHz), caused by standing waves established by our trapping fields. We compare and contrast the switching dynamics of these two resonances and demonstrate optical switching using both resonances. Finally, we consider the applicability of the narrow, free-space resonance to the slowing of a weak probe field. [1] J. Guo, P.R. Berman, B. Dubetsky and G. Grynberg PRA, 46, 1426 (1992). [2] (a) P. Verkerk, B. Loumis, C. Salomon, C. Cohen-Tannoudji, J. Courtois PRL, 68, 3861 (1992). (b) G. Grynberg, J-Y Courtois, B. Lounis, P. Verkerk PRL, 72, 3017 (1994). [3] (a) T. Brzozowski, M. Brzozowska, J. Zachorowski, M. Zawada, W. Gawlik PRA, 71, 013401 (2005). (b) M. Brzozowska, T. Brzozowski J. Zachorowski, W. Gawlik PRA, 72, 061401(R), (2005).

Narducci, F. A.; Desavage, S. A.; Gordon, K. H.; Duncan, D. L.; Welch, G. R.; Davis, J. P.

2010-03-01

184

Identification of Benzethonium Chloride in Commercial Grapefruit Seed Extracts  

Microsoft Academic Search

Commercial grapefruit seed extracts (GSE) were extracted with chloroform. The solvent was evaporated, and the resulting solid was subsequently analyzed by high-performance liquid chromatography, electrospray ionization mass spectrometry, nuclear magnetic resonance (NMR) spectroscopy, and elemental analysis (by proton-induced X-ray emission (PIXE) analysis). The main constituent was identified as benzethonium chloride, a synthetic antimicrobial agent commonly used in cosmetics and other

Gary R. Takeoka; Lan T. Dao; Rosalind Y. Wong; Leslie A. Harden; Noreen Mahoney

2001-01-01

185

Probing Studentsâ Understanding of Resonance  

NSDL National Science Digital Library

Resonant phenomena play a crucial role in magnetic resonance imaging (MRI), a widely used medical tool in today's society. The basic features of the resonance in MRI can be taught by looking at the resonance of a compass driven by an electromagnetic field. However, resonance in a oscillating magnetic field is not a phenomenon that is familiar to most students. Thus, as a precursor to creating instructional materials, we investigated how students applied their learning about resonance as traditionally taught to this novel system.

Murphy, Sytil K.; Mcbride, Dyan L.; Gross, Josh; Zollman, Dean A.

2010-01-19

186

Dipole Coupling of a Double Quantum Dot to a Microwave Resonator  

NASA Astrophysics Data System (ADS)

We demonstrate the realization of a hybrid solid-state quantum device, in which a semiconductor double quantum dot is dipole coupled to the microwave field of a superconducting coplanar waveguide resonator. The double dot charge stability diagram extracted from measurements of the amplitude and phase of a microwave tone transmitted through the resonator is in good agreement with that obtained from transport measurements. Both the observed frequency shift and linewidth broadening of the resonator are explained considering the double dot as a charge qubit coupled with a strength of several tens of MHz to the resonator.

Frey, T.; Leek, P. J.; Beck, M.; Blais, A.; Ihn, T.; Ensslin, K.; Wallraff, A.

2012-01-01

187

Screening Resonances In Plasmas  

SciTech Connect

When it was suggested that a new recombination mechanism (Resonant Radiative Recombination (RRR)) which, based on very general physical arguments, should happen in dense plasmas and promises to provide useful information for the local temperature and density diagnostics of plasmas, they assumed the existence of screening resonances. For model potentials the existence of screening resonances has been demonstrated beyond reasonable doubt in a number of calculations. The key question, how well those potentials describe the dominant effects of a real plasma remains open. The relation of theoretical predictions to experimentally measurable effects is an important issue at the present stage of their research. In particular, RRR is expected to account for enhanced recombination rates of low energetic electrons with their ions, since the first stage is the resonant capture of a slow electron by an atom or ion. The mechanism that traps an electron is a combination of complicated many-body interactions of the ions and electrons. For clarity they start here, however, with a discussion in terms of local potential traps the shapes of which are determined predominantly and in an average way by two factors: the degree of screening present at the ionic site and the degree of short-range order in the immediate neighborhood of this ion.

Winkler, P.

1998-12-01

188

Resonances, clusters and deformation  

SciTech Connect

The interrelation of the high-lying molecular resonances, populated in heavy ion reactions, and the shape isomers of special deformation is investigated in terms of simple structural selection rules. Furthermore, it is shown that symmetry-studies can provide us with detailed spectroscopic information, as well.

Cseh, J. [Institute of Nuclear Research, Hungarian Academy of Sciences, Debrecen, Pf. 51, 4001 (Hungary); Darai, J. [Institute of Experimental Physics, University of Debrecen, Debrecen, Pf. 105, 4010 (Hungary)

2009-03-04

189

Clinical magnetic resonance imaging  

SciTech Connect

This book presents clinical applications of magnetic resonance imaging with a strong clinical orientation. Covers technique, instrumentation, and contrast agents. Describes MRI of the neck, brain, heart, spine, TMJ and orbit, chest abdomen, pelvis, and the joints. Also includes a high field atlas of the central nervous system.

Brady, T.J.; Edelman, R.R.

1988-01-01

190

Magnetoelectric resonance engine  

SciTech Connect

This patent describes a magnetoelectric resonance thermal machine. It comprises a reciprocating, multiple-piston, Alpha-type Stirling-cycle mechanical assembly; an electronic quadrature phase-lock circuit; an ancillary external energy and mass transfer subsystem; and a master microcomputer control system.

Moscrip, W.M.

1992-09-15

191

Magnetic Resonance Imaging  

NSDL National Science Digital Library

This lesson ties the preceding lessons together and brings students back to the grand challenge question on MRI safety. During this lesson, students focus on the logistics of magnetic resonance imaging as well as the MRI hardware. Students can then integrate this knowledge with their acquired knowledge on magnetic fields to solve the challenge question.

VU Bioengineering RET Program, School of Engineering,

192

A resonance theory of \\  

Microsoft Academic Search

It is suggested that the resonance theory adequately accounts for those of Rohracher's findings which he quotes as being inconsistent with it and that there is at present no evidence for or need to suggest a relationship between the frequency of microvibrations and that of the \\

James G. L. Williams

1964-01-01

193

Nuclear Magnetic Resonance.  

National Technical Information Service (NTIS)

Nuclear Magnetic Resonance (NMR) is a new technique which has been introduced into the medical diagnostic imaging field. NMR is a method of imaging the body by exposing it to low-energy magnetic and radio-frequency fields. This process yields bio-chemical...

D. Watkins N. Netherton

1983-01-01

194

Magnetic Resonance Annual, 1985  

SciTech Connect

The inaugural volume of Magnetic Resonance Annual includes reviews of MRI of the posterior fossa, cerebral neoplasms, and the cardiovascular and genitourinary systems. A chapter on contrast materials outlines the mechanisms of paramagnetic contrast enhancement and highlights several promising contrast agents.

Kressel, H.Y.

1985-01-01

195

Magnetic resonance fingerprinting.  

PubMed

Magnetic resonance is an exceptionally powerful and versatile measurement technique. The basic structure of a magnetic resonance experiment has remained largely unchanged for almost 50?years, being mainly restricted to the qualitative probing of only a limited set of the properties that can in principle be accessed by this technique. Here we introduce an approach to data acquisition, post-processing and visualization--which we term 'magnetic resonance fingerprinting' (MRF)--that permits the simultaneous non-invasive quantification of multiple important properties of a material or tissue. MRF thus provides an alternative way to quantitatively detect and analyse complex changes that can represent physical alterations of a substance or early indicators of disease. MRF can also be used to identify the presence of a specific target material or tissue, which will increase the sensitivity, specificity and speed of a magnetic resonance study, and potentially lead to new diagnostic testing methodologies. When paired with an appropriate pattern-recognition algorithm, MRF inherently suppresses measurement errors and can thus improve measurement accuracy. PMID:23486058

Ma, Dan; Gulani, Vikas; Seiberlich, Nicole; Liu, Kecheng; Sunshine, Jeffrey L; Duerk, Jeffrey L; Griswold, Mark A

2013-03-14

196

Cross Resonant Optical Antenna  

Microsoft Academic Search

We propose a novel cross resonant optical antenna consisting of two perpendicular nanosized gold dipole antennas with a common feed gap. We demonstrate that the cross antenna is able to convert propagating fields of any polarization state into correspondingly polarized, localized, and enhanced fields and vice versa. The cross antenna structure therefore opens the road towards the control of light-matter

P. Biagioni; J. S. Huang; L. Duò; M. Finazzi; B. Hecht

2009-01-01

197

Nuclear magnetic resonance gyroscopes  

Microsoft Academic Search

Nuclear magnetic resonance gyroscopes (NMRGs) detect rotation as a shift in the Larmor precession frequency of nuclear spins. A review of the open literature on NMRGs is presented, which includes an introduction to the spectroscopic techniques that enable NMRGs and a discussion of the design details for several specific NMRGs that have been built.

E. A. Donley

2010-01-01

198

Tandem resonator reflectance modulator  

Microsoft Academic Search

A wide band optical modulator is grown on a substrate as tandem Fabry-Perot resonators including three mirrors spaced by two cavities. The absorption of one cavity is changed relative to the absorption of the other cavity by an applied electric field, to cause a change in total reflected light, as light reflecting from the outer mirrors is in phase and

I. J. Fritz; J. R. Wendt

1994-01-01

199

Theory of resonance reactions  

Microsoft Academic Search

A general formal theory of resonance reactions and scattering is ; developed without the use of channel radii. The approach employed allows a ; simple physical interpretation of the two energies, one of which must be kept ; fixed while the other one is varied in order for a Breit-Wigner denominator to ; vanish. A new result, obtained without a

Luciano Fonda; Roger G. Newton

1960-01-01

200

D-Wave Resonances in Three-Body System Ps- with Pure Coulomb and Screened Coulomb (Yukawa) Potentials  

NASA Astrophysics Data System (ADS)

We have investigated the doubly excited 1 D e resonance states of Ps- interacting with pure Coulomb and screened Coulomb (Yukawa) potentials employing highly correlated wavefunctions. For pure Coulomb interaction, in the framework of stabilization method and complex coordinate rotation method we have obtained two resonances below the n = 2 threshold of the Ps atom. For screened Coulomb interaction, we employ the stabilization method to extract resonance parameters. Resonance energies and widths for the 1 D e resonance states of Ps- for different screening parameter ranging from infinity (pure Coulomb case) to a small value are also reported.

Kar, Sabyasachi; Ho, Y. K.

2009-04-01

201

Packaging Precision Quartz Crystal Resonators.  

National Technical Information Service (NTIS)

The causes of aging and thermal hysteresis in quartz resonators are reviewed with emphasis on those aspects which can be influenced by the resonator's packaging. A microcircuit compatible ceramic package design is proposed which is aimed toward optimizing...

E. Hafner J. R. Vig

1973-01-01

202

Coherent synchro-betatron resonance  

SciTech Connect

Coherent synchro-betatron resonances can present a serious limit for low-energy synchrotrons with strong space charge. Here, an excitation of a dipole transverse mode is considered at resonance condition.

Burov, A.; Lebedev, V.; /Fermilab

2006-12-01

203

Giant resonances: reaction theory approach.  

National Technical Information Service (NTIS)

The study of giant resonances through the use of reaction theory approach is presented and discussed. Measurements of cross-sections to the many available decay channels following excitation of giant multipole resonances (GMR) led one to view these phenom...

A. F. R. Toledo Piza G. A. Foglia

1989-01-01

204

Microwave Dielectric Resonator-Tuning.  

National Technical Information Service (NTIS)

Dielectric resonators have applications as low-loss compact filters in the microwave region. Tuning characteristics of dielectric resonators that might allow for temperature compensation and frequency variability were investigated both theoretically and e...

U. H. W. Lammers M. R. Stiglitz

1974-01-01

205

Hybrid MEMS resonators and oscillators  

Microsoft Academic Search

With quality factors (Q) often-exceeding 10,000, vibrating micromechanical resonators have emerged as leading candidates for on-chip versions of high-Q resonators used in wireless communications systems. However, as in the case for transistors, extending the frequency of MEMS resonators generally entails scaling of resonator dimensions. Unfortunately, smaller size often coincides with lower-power handling capability and increased motional impedance. In this paper

Sunil A. Bhave

2011-01-01

206

PITFALLS OF SEQUENTIAL EXTRACTION  

EPA Science Inventory

An increasing number of researchers are using sequential extraction to determine the speciation of trace elements in sediments. nfortunately, sequential extraction methods have not been successfully validated. he results are simply taken as providing "operational definitions" of ...

207

Tevatron Extraction Microcomputer.  

National Technical Information Service (NTIS)

Extraction in the Fermilab Tevatron is controlled by a multi-processor Multibus microcomputer system called QXR (Quad eXtraction Regulator). QXR monitors several analog beam signals and controls three sets of power supplies: the ''bucker'' and ''pulse'' m...

L. Chapman D. A. Finley M. Harrison W. Merz

1985-01-01

208

Electromagnetic excitation of the Delta(1232) resonance  

SciTech Connect

We review the description of the lowest-energy nucleon excitation--the Delta(1232)-resonance. Much of the recent effort has been focused on the precision measurements of the nucleon to Delta transition by means of electromagnetic probes. We review the results of those measurements and confront them with the state-of-the-art calculations based on chiral effective-field theories (EFT), lattice QCD, and QCD-inspired models. Some of the theoretical approaches are reviewed in detail. In particular, we describe the chiral EFT of QCD in the energy domain of the Delta-resonance, and its applications to the electromagnetic nucleon-to-Delta transition (gamma N Delta). We also describe the recent dynamical and unitary-isobar models of pion electroproduction which are extensively used in the extraction of the gamma* N Delta form factors from experiment. Furthermore, we discuss the link of the gamma* N Delta form factors to generalized parton distributions (GPDs), as well as the predictions of perturbative QCD for these transition form factors. The present status of understanding the Delta-resonance properties and the nature of its excitation is summarized.

V. Pascalutsa; M. Vanderhaeghen; Shin Nan Yang

2006-09-05

209

Fano resonances in metallic grating coupled whispering gallery mode resonator  

NASA Astrophysics Data System (ADS)

We experimentally demonstrate robust coupling of a metallic grating to the whispering gallery mode (WGM) of a microsphere resonator. The metallic grating coupled resonator forms a hybrid system that generates Fano resonances. Through theoretical modeling and experimental demonstration, we analyze this vertically coupled Fano-WGM structure. It is found that the Fano resonances originate from the interaction between the high-Q WGM and direct reflection of the grating. The Fano resonance shape is found to depend on the polarization state of the incident wave.

Zhou, Yanyan; Zhu, Di; Yu, Xia; Ding, Wei; Luan, Feng

2013-10-01

210

On the complex resonant frequency of open dielectric resonators  

NASA Astrophysics Data System (ADS)

An analytical method is presented for calculating accurately the complex resonant frequency of dielectric pillbox resonators. In this method, an approximted field of the resonator is expanded into a truncated series of solutions of the Helmholtz equation in the spherical coordinates, and the boundary condition on the resonator surface is treated in the least-squares sense. The resonant frequency and the intrinsic Q value due to radiation loss are obtained in the form of approximation converging to the exact values. Numerical results are compared with previously published calculations, which show that the present method is a relatively simple and effective one.

Tsuji, M.; Shigesawa, H.; Takiyama, K.

1983-05-01

211

Continuous-wave intra-cavity singly resonant optical parametric oscillator with resonant wave output coupling.  

PubMed

We report herein the enhancement in both power and efficiency performance of a continuous-wave intra-cavity singly resonant optical parametric oscillator (ICSRO) by introducing finite resonant wave output coupling. While coupling out the resonant wave to useful output, the output coupling increases the SRO threshold properly thus suppresses the back-conversion under high pump power. Therefore, the down-conversion efficiency is maintained under high pump without having to raise the threshold by defocusing. With a T = 9.6% signal wave output coupler used, the SRO threshold is 2.46 W and the down-conversion efficiency is 72.9% under the maximum pump power of 21.4 W. 1.43 W idler power at 3.66 ?m and 5.03 W signal power at 1.5 ?m are obtained, corresponding to a total extraction efficiency of 30.2%. The resonant wave out coupling significantly levels up the upper limit for the power range where the ICSRO exhibits high efficiency, without impeding its advantage of low threshold. PMID:23262741

Sheng, Quan; Ding, Xin; Shang, Ce; Li, Bin; Fan, Chen; Zhang, Haiyong; Yu, Xuanyi; Wen, Wuqi; Ma, Yila; Yao, Jianquan

2012-12-01

212

Dualband Split Dielectric Resonator Antenna  

Microsoft Academic Search

A dualband dielectric resonator antenna (DRA) is designed by splitting a rectilinear dielectric resonator (DR) and carving notches off the DR. It is observed that notches engraved at different positions affect different modes. Removal of dielectric material from where the electric field is strong incurs a significant increase in resonant frequency. The abrupt change of normal electric field across the

Tze-Hsuan Chang; Jean-Fu Kiang

2007-01-01

213

Surface Wave Resonators on Silicon.  

National Technical Information Service (NTIS)

In this paper two topics new to the ZnO-on-Si resonator development are discussed: The use of SAW resonators to determine the effect of a laser anneal on layered medium propagation loss; and A conceptually new device, called the mode conversion resonator,...

S. J. Martin R. L. Gunshor T. J. Miller S. Datta R. F. Pierret

1983-01-01

214

Guided Resonance Dielectric Filter Systems.  

National Technical Information Service (NTIS)

We theoretically introduce a new type of optical all-pass filter based on guided resonance in coupled photonic crystal slabs. The filter exhibits near-complete transmission for both on- and off-resonant frequencies and yet generates large resonant group d...

O. Solgaard S. Fan W. Suh

2004-01-01

215

Impurity resonance states in semiconductors  

SciTech Connect

The present-day situation in studies of localized and resonance impurity states in quantum-dimensional structures and stressed semiconductors is discussed. Resonance optical transitions caused by interaction with optical phonons are also considered. Various methods for calculating the characteristics of both donor and acceptor resonance and localized states are analyzed; a large body of experimental data is reported and discussed.

Aleshkin, V. Ya.; Gavrilenko, L. V. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Odnoblyudov, M. A.; Yassievich, I. N. [Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation)], E-mail: Irina.Yassievich@mail.ioffe.ru

2008-08-15

216

Magnetic Resonance Facility (Fact Sheet)  

SciTech Connect

This fact sheet provides information about Magnetic Resonance Facility capabilities and applications at NREL's National Bioenergy Center. Liquid and solid-state analysis capability for a variety of biomass, photovoltaic, and materials characterization applications across NREL. NREL scientists analyze solid and liquid samples on three nuclear magnetic resonance (NMR) spectrometers as well as an electron paramagnetic resonance (EPR) spectrometer.

Not Available

2012-03-01

217

Exotic Grazing Resonances in Nanowires  

Microsoft Academic Search

We investigate electromagnetic scattering from nanoscale wires and reveal for the first time, the emergence of a family of exotic resonances, or enhanced fields, for source waves close to grazing incidence. These grazing resonances can have a much higher Q factor, broader bandwidth, and are much less susceptible to material losses than the well known surface plasmon resonances found in

Simin Feng; Klaus Halterman

2009-01-01

218

Repetitive resonant railgun power supply  

DOEpatents

A repetitive resonant railgun power supply provides energy for repetitively propelling projectiles from a pair of parallel rails. The supply comprises an energy storage capacitor, a storage inductor to form a resonant circuit with the energy storage capacitor and a magnetic switch to transfer energy between the resonant circuit and the pair of parallel rails for the propelling of projectiles.

Honig, Emanuel M. (Los Alamos, NM); Nunnally, William C. (Los Alamos, NM)

1988-01-01

219

Resonant cavity enhanced photonic devices  

Microsoft Academic Search

We review the family of optoelectronic devices whose performance is enhanced by placing the active device structure inside a Fabry-Perot resonant microcavity. Such resonant cavity enhanced (RCE) devices benefit from the wavelength selectivity and the large increase of the resonant optical field introduced by the cavity. The increased optical field allows RCE photodetector structures to be thinner and therefore faster,

M. Selim Ünlü; Samuel Strite

1995-01-01

220

Resonances for matrix Schrödinger operators  

Microsoft Academic Search

We study the resonances of matrix Schrödinger operators,\\u000amotivated by the Born-Oppenheimer approximation. We give a simple\\u000acriterion for the potential to generate resonances. This criterion\\u000aalso gives the location of the resonances generated.

L. Nedelec

2001-01-01

221

Endovascular extraction techniques  

PubMed Central

The use of lead extraction is expanding with the introduction of new endovascular extraction techniques. Indications for extraction of chronically implanted pacemaker leads have been classified as mandatory, necessary or discretionary, but their rationale is often based on clinical judgement without corresponding support from the literature. We reviewed the literature of pacemaker lead-related complications as a starting point for discussing the indications for lead extraction. ImagesFigure 1Figure 2Figure 3

Bracke, F.A.; Meijer, A.; van Gelder, B.

2001-01-01

222

Processed anthocyanin pigment extracts  

US Patent & Trademark Office Database

The stability of anthocyanin pigment extracts and food products containing anthocyanin extracts is enhanced by removal from the anthocyanin pigment extracts of nutrients which support yeast growth, constituents which react to produce off-flavor, and constituents which catalyze oxidation. These undesirable materials contained in anthocyanin extracts are removed by subjecting the extracts to ultrafiltration or dialysis to remove low molecular weight components from the extracts. The extracts are also subjected to ion exchange to remove additional of these undesirable constituents. Sufficient of these undesirable constituents can be removed from anthocyanin extracts so that, e.g., carbonated beverages containing the extracts may not support sufficient growth of yeasts to cause the beverages to become hazy and/or have an off-flavor, and so that when the extracts are used to prepare dry beverage powder mixtures after prolonged shelf storage, the mixtures may not obtain an off-flavor. Moreover, the oxidative stability and photostability of the anthocyanin pigment extracts may be enhanced by the process of this invention. Such processed anthocyanin extracts may have higher tinctoral powers, e.g., more brilliant red colors, and are less hygroscopic, and thus they may be suitable for coloring various solid food products including liquid and powder concentrates.

Hilton; Barney W. (Dallas, TX); Lin; Robert I. (Irving, TX); Topor; Michael G. (Farmer's Branch, TX)

1982-03-16

223

Content Extraction Signatures  

Microsoft Academic Search

Motivated by emerging needs in online interactions, we dene a new type of digital signature called a 'Content Extraction Signature' (CES). A CES allows the owner, Bob, of a document signed by Alice, to produce an 'extracted signature' on selected extracted portions of the original document, which can be veried to originate from Alice by any third party Cathy, while

Ron Steinfeld; Laurence Bull; Yuliang Zheng

2001-01-01

224

Extractive Distillation: A Review  

Microsoft Academic Search

Extractive distillation is more and more commonly applied in industry, and becomes an important separation method in chemical engineering. This paper provides an in?depth review for extractive distillation. Separation sequence of the columns, combination with other separation processes, tray configuration and operation policy are included in process of extractive distillation. Since the solvent plays an important role in the design

Zhigang Lei; Chengyue Li; Biaohua Chen

2003-01-01

225

Energetics of stochastic resonance  

NASA Astrophysics Data System (ADS)

In this paper, we discuss the motion of a Brownian particle in a double-well potential driven by a periodic force in terms of energies delivered by the periodic and the noise forces and energy dissipated into the viscous environment. It is shown that, while the power delivered by the periodic force to the Brownian particle is controlled by the strength of the noise, the power delivered by the noise itself is independent of the amplitude and frequency of the periodic force. The implications of this result for the mechanism of stochastic resonance in an equilibrium system is that it is not energy from the noise force which enhances a small periodic force, but rather an increase of energy delivered by the periodic force, regulated by the strength of the noise. We further re-evaluate the frequency dependence of stochastic resonance in terms of energetic terms including efficiency.

Jung, Peter; Marchesoni, Fabio

2011-12-01

226

High field magnetic resonance  

US Patent & Trademark Office Database

A magnetic resonance system is disclosed. The system includes a transceiver having a multichannel receiver and a multichannel transmitter, where each channel of the transmitter is configured for independent selection of frequency, phase, time, space, and magnitude, and each channel of the receiver is configured for independent selection of space, time, frequency, phase and gain. The system also includes a magnetic resonance coil having a plurality of current elements, with each element coupled in one to one relation with a channel of the receiver and a channel of the transmitter. The system further includes a processor coupled to the transceiver, such that the processor is configured to execute instructions to control a current in each element and to perform a non-linear algorithm to shim the coil.

2010-09-21

227

Saw Blades and Resonance  

NASA Astrophysics Data System (ADS)

This paper describes an inexpensive, classroom experiment that allows students to quantitatively investigate resonance using a hacksaw blade. The blade clamped to the edge of a table forms a cantilever that may vibrate at any of a number of preferred frequencies. A small cylindrical magnet is fixed to the saw blade. An electromagnetic coil powered by a frequency generator causes large-amplitude vibrations of the saw blade at the resonant frequencies. Vibrations of a similar system, a vibrating car antenna, have been discussed by Newburgh and Newburgh.1 The dramatic increases in the oscillation amplitude are both instructive and fascinating. Analogies may be drawn to systems ranging from a child on a swing to the Tacoma Narrows bridge.

Liebl, Michael

2005-05-01

228

Surface Plasmon Resonance Laboratory  

NSDL National Science Digital Library

This lab focuses on the optical generation and modeling of Surface Plasmons, in particular the attempt of predicting and generating a resonance condition in a three layer system; glass, metal and air. The lab is designed to easily create a film and test itâs resonance with minimal cost and time to prepare the setup between testing. This concept can be demonstrated in a more elaborate setup, but is not necessary unless this demonstration will be used as a research instrument afterwards. This lab is comprised of four main parts: 1. Understanding the theory of SPR, through deriving the Fresnel equations from Maxwell Equations. 2. Determining the optimal conditions for the Prism Coating (Modeling). 3. Fabricating the coated prism with a deposition system. 4. Comparing modeling and experiment, explain error.

Sã¡nchez, Erik

2010-11-24

229

Feshbach resonances in ultracold gases  

SciTech Connect

Feshbach resonances are the essential tool to control the interaction between atoms in ultracold quantum gases. They have found numerous experimental applications, opening up the way to important breakthroughs. This review broadly covers the phenomenon of Feshbach resonances in ultracold gases and their main applications. This includes the theoretical background and models for the description of Feshbach resonances, the experimental methods to find and characterize the resonances, a discussion of the main properties of resonances in various atomic species and mixed atomic species systems, and an overview of key experiments with atomic Bose-Einstein condensates, degenerate Fermi gases, and ultracold molecules.

Chin Cheng; Grimm, Rudolf; Julienne, Paul; Tiesinga, Eite [Department of Physics and James Franck Institute, University of Chicago, Chicago, Illinois 60637 (United States); Center for Quantum Physics and Institute of Experimental Physics, University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck (Austria) and Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, Otto-Hittmair-Platz 1, 6020 Innsbruck (Austria); Joint Quantum Institute, National Institute of Standards and Technology and University of Maryland, 100 Bureau Drive, Gaithersburg, Maryland 20899-8423 (United States)

2010-04-15

230

Pulp Refining at Resonance  

NASA Astrophysics Data System (ADS)

A disc refiner model for stock preparation for paper and board manufacture, is derived. The torsional response of the machine under operating conditions is considered. Resonance excitation via drive and flow pulsation variations is achieved enabling optimum torsional oscillatory behaviour to be attained. The effect of this action on the reciprocal shredding and shearing performance of the machine is commented upon and simulated response characteristics are presented.

Whalley, R.; Mitchell, D.

1999-07-01

231

Broadband ferromagnetic resonance spectrometer  

Microsoft Academic Search

The continuous wave ferromagnetic resonance (FMR) spectrometer operating in multioctave (0.05–40 GHz) frequency range has been built to investigate the magnetic properties of thin ferromagnetic films in the temperature range of 4–420 K. The spectrometer has two probeheads: one is the X-band microwave reflection cavity used to perform express room temperature measurements and the other is an in-cryostat microstrip line

V. P. Denysenkov; A. M. Grishin

2003-01-01

232

Broadband ferromagnetic resonance spectrometer  

Microsoft Academic Search

The continuous wave ferromagnetic resonance (FMR) spectrometer operating in multioctave (0.05-40 GHz) frequency range has been built to investigate the magnetic properties of thin ferromagnetic films in the temperature range of 4-420 K. The spectrometer has two probeheads: one is the X-band microwave reflection cavity used to perform express room temperature measurements and the other is an in-cryostat microstrip line

V. P. Denysenkov; A. M. Grishin

2003-01-01

233

Peripheral Production of Resonances  

Microsoft Academic Search

We review the peripheral cross-sections of resonances that cannot be produced by pi-exchange. Explicitly we consider the four nonets of mesons n the L = 1 quark classification, JP = 0+ piN(980); 1+, e.g., A1, B; 2+, e.g., A2. We detail the constraints of SU3, exchange degeneracy, factorization, pole extrapolation, Watson's theorem and duality as they have been gleaned from

Geoffrey Fox

1972-01-01

234

Tandem resonator reflectance modulator  

SciTech Connect

A wide band optical modulator is grown on a substrate as tandem Fabry-Perot resonators including three mirrors spaced by two cavities. The absorption of one cavity is changed relative to the absorption of the other cavity by an applied electric field, to cause a change in total reflected light, as light reflecting from the outer mirrors is in phase and light reflecting from the inner mirror is out of phase with light from the outer mirrors. 8 figs.

Fritz, I.J.; Wendt, J.R.

1994-09-06

235

Doubly Excited 1,3 P e Resonance States of the Positronium Negative Ion with Coulomb and Screened Coulomb Potentials  

NASA Astrophysics Data System (ADS)

We have investigated the doubly excited 1,3 P e resonance states of positronium negative ion with Coulomb and screened Coulomb potentials using highly accurate correlated exponential wavefunctions. For Coulomb interaction, the stabilization and the complex-rotation methods are employed to extract resonance parameters (resonance positions and widths). We have obtained two 1 P e resonances and three 3 P e resonances below the n = 3 Ps threshold. In addition to Feshbach resonances lying below n = 3 Ps threshold, we have calculated one 3 P e shape resonances lying above the Ps ( n = 2) threshold. For screened Coulomb (Yukawa) interaction, we employ the stabilization method to extract resonance parameters as functions screening parameter. The resonance energies and widths for 1,3 P e resonance states of Ps- below the n = 3 Ps threshold for different screening parameters ranging from infinity (Coulomb case) to small values are reported, along with the Ps(3S) and Ps(3P) threshold energies. The screened Coulomb results for the 1,3 P e resonance states are reported for the first time in the literature.

Kar, Sabyasachi; Ho, Y. K.

2009-09-01

236

Nonlinear Fano-Feshbach resonances  

NASA Astrophysics Data System (ADS)

We study the wave scattering in an one-dimensional discrete system with two side-coupled defects. Each of the defects exhibits the Fano resonance as a resonant suppression of transmission, i.e., resonant reflection. We demonstrate that the interaction between two Fano resonances may give rise to a birth of a very narrow resonance. This effect may be understood in terms of the overlapping resonances, as suggested by Feshbach [Ann. Phys. 5, 357 (1958)]. We consider two cases, when the defects are coupled either locally or nonlocally to the discrete array. In the latter case, a sharp asymmetric resonance appears with a large quality factor. We demonstrate that by introducing a nonlinearity at side-coupled defects a closed loop in the nonlinear transmission coefficient may appear, which results in bistable response.

Miroshnichenko, Andrey E.

2009-02-01

237

Nuclear magnetic resonance contrast agents  

DOEpatents

This invention relates to the field of nuclear magnetic resonance imaging and nuclear magnetic resonance spectroscopy, also known simply as magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS). MRI and MRS are particularly useful in medical research and diagnosis. MRI may be used in addition to x-ray imaging. This invention concerns a family of contrast agents for use in magnetic resonance imaging and a method of enhancing the contrast of magnetic resonance images of an object by incorporating a contrast agent of this invention into the object prior to forming the images or during formation of the images. A contrast agent of this invention is a paramagnetic lanthanide hexaazamacrocyclic molecule, where a basic example has the formula LnC{sub 16}H{sub 14}N{sub 6}. Important applications of the invention are in medical diagnosis, treatment, and research, where images of portions of a human body are formed by means of magnetic resonance techniques. 2 figs.

Smith, P.H.; Brainard, J.R.; Jarvinen, G.D.; Ryan, R.R.

1989-01-24

238

METAL EXTRACTION PROCESS  

DOEpatents

An improved method for extracting uranium from aqueous solutions by solvent extraction is presented. A difficulty encountered in solvent extraction operations using an organic extractant (e.g., tributyl phosphate dissolved in kerosene or carbon tetrachloride) is that emulsions sometimes form, and phase separation is difficult or impossible. This difficulty is overcome by dissolving the organic extractant in a molten wax which is a solid at operating temperatures. After cooling, the wax which now contains the extractant, is broken into small particles (preferably flakes) and this wax complex'' is used to contact the uranium bearing solutions and extract the metal therefrom. Microcrystalline petroleum wax and certain ethylene polymers have been found suitable for this purpose.

Lewis, G.W. Jr.; Rhodes, D.E.

1957-11-01

239

Vessel boundary extraction based on a global and local deformable physical model with variable stiffness  

Microsoft Academic Search

Reliable and efficient vessel cross-sectional boundary extraction is very important for many medical magnetic resonance (MR) image studies. General purpose edge detection algorithms often fail for medical MR images processing due to fuzzy boundaries, inconsistent image contrast, missing edge features, and the complicated background of MR images. In this regard, we present a vessel cross-sectional boundary extraction algorithm based on

Yong-Lin Hu; W. J. Rogers; D. A. Coast; C. M. Kramer; N. Reichek

1998-01-01

240

Resonant tunneling IR detectors  

NASA Astrophysics Data System (ADS)

Researchers propose a novel semiconductor heterojunction photodetector which would have a very low dark current and would be voltage tunable. A schematic diagram of the device and its band structure are shown. The two crucial components of the device are a cathode (InGaAs) whose condition band edge is below the conduction band edge of the quantum wells and a resonant tunneling filter (GaAs-AlGaAs). In a standard resonant tunneling device the electrodes are made of the same material as the quantum wells, and this device becomes highly conducting when the quantum levels in the wells are aligned with the Fermi level in the negatively biased electrode. In contrast, the researchers device is essentially non-conducting under the same bias conditions. This is because the Fermi Level of the cathode (InGaAs) is still well below the quantum levels so that no resonant transport occurs and the barriers (AlGaAs) effectively block current flow through the device. However, if light with the same photon energy as the conduction-band discontinuity between the cathode and the quantum wells, E sub c3-E sub c1, is shone on the sample, free carriers will be excited to an energy corresponding to the lowest quantum level in the well closest to the cathode (hv plue E sub c1 = E sub o). These electrons will resonantly tunnel through the quantum wells and be collected as a photocurrent in the anode (GaAs). To improve the quantum efficiency, the cathode (InGaAs) should be very heavily doped and capped with a highly reflective metal ohmic contact. The thickness of the device should be tailored to optimize thin film interference effects and afford the maximum absorption of light. Because the device relies on resonant tunneling, its response should be very fast, and the small voltages needed to change the responsivity should allow for very high frequency modulation of the photocurrent. In addition, the device is tuned to a specific photon energy so that it can be designed to detect a fairly narrow range of wavelengths. This selectivity is important for reducing the photocurrent due to spurious light sources.

Woodall, Jerry M.; Smith, T. P., III

1990-07-01

241

Cost effectiveness of magnetic resonance imaging in the neurosciences.  

PubMed Central

OBJECTIVES--To measure, in a service setting, the effect of magnetic resonance imaging on diagnosis, diagnostic certainty, and patient management in the neurosciences; to measure the cost per patient scanned; to estimate the marginal cost of imaging and compare this with its diagnostic impact; to measure changes in patients' quality of life; and to record the diagnostic pathway leading to magnetic resonance imaging. DESIGN--Controlled observational study using questionnaires on diagnosis and patient management before and after imaging. Detailed costing study. Quality of life questionnaires at the time of imaging and six months later. Diagnostic pathways extracted from medical records for a representative sample. SETTING--Regional superconducting 1.5 T magnetic resonance service. SUBJECTS--782 consecutive neuroscience patients referred by consultants for magnetic resonance imaging during June 1988-9; diagnostic pathways recorded for 158 cases. MAIN OUTCOME MEASURES--Costs of magnetic resonance imaging and preliminary investigations; changes in planned management and resulting savings; changes in principal diagnosis and diagnostic certainty; changes in patients' quality of life. RESULTS--Average cost of magnetic resonance imaging was estimated at 206.20/patient pounds (throughput 2250 patients/year, 1989-90 prices including contrast and upgrading). Before magnetic resonance imaging diagnostic procedures cost 164.40/patient pounds (including inpatient stays). Management changed after imaging in 208 (27%) cases; saving an estimated 80.90/patient pounds. Confidence in planned management increased in a further 226 (29%) referrals. Consultants' principal diagnosis changed in 159 of 782 (20%) referrals; marginal cost per diagnostic change was 626 pounds. Confidence in diagnosis increased in 236 (30%) referrals. No improvement in patients' quality of life at six month assessment. CONCLUSIONS--Any improvement in diagnosis with magnetic resonance imaging is achieved at a higher cost. Techniques for monitoring the cost effectiveness of this technology need to be developed.

Szczepura, A K; Fletcher, J; Fitz-Patrick, J D

1991-01-01

242

Texture Coding in the Rat Whisker System: Slip-Stick Versus Differential Resonance  

PubMed Central

Rats discriminate surface textures using their whiskers (vibrissae), but how whiskers extract texture information, and how this information is encoded by the brain, are not known. In the resonance model, whisker motion across different textures excites mechanical resonance in distinct subsets of whiskers, due to variation across whiskers in resonance frequency, which varies with whisker length. Texture information is therefore encoded by the spatial pattern of activated whiskers. In the competing kinetic signature model, different textures excite resonance equally across whiskers, and instead, texture is encoded by characteristic, nonuniform temporal patterns of whisker motion. We tested these models by measuring whisker motion in awake, behaving rats whisking in air and onto sandpaper surfaces. Resonant motion was prominent during whisking in air, with fundamental frequencies ranging from approximately 35 Hz for the long Delta whisker to approximately 110 Hz for the shorter D3 whisker. Resonant vibrations also occurred while whisking against textures, but the amplitude of resonance within single whiskers was independent of texture, contradicting the resonance model. Rather, whiskers resonated transiently during discrete, high-velocity, and high-acceleration slip-stick events, which occurred prominently during whisking on surfaces. The rate and magnitude of slip-stick events varied systematically with texture. These results suggest that texture is encoded not by differential resonant motion across whiskers, but by the magnitude and temporal pattern of slip-stick motion. These findings predict a temporal code for texture in neural spike trains.

Wolfe, Jason; Hill, Dan N; Pahlavan, Sohrab; Drew, Patrick J; Kleinfeld, David; Feldman, Daniel E

2008-01-01

243

Quartz crystal microbalance based on torsional piezoelectric resonators  

SciTech Connect

A quartz crystal microbalance (QCM) is described, which is based on a torsional resonator, rather than a conventional thickness-shear resonator. Typical applications are measurements of film thickness in the coating industry and monitoring of biofouling. The torsional QCM is about a factor of 100 less sensitive than the conventional QCM. On the other hand, it can probe film thicknesses in the range of hundreds of microns, which is impossible with the conventional QCM due to viscoelastic artifacts. Data acquisition and data analysis proceed in analogy to the conventional QCM. An indicator of the material's softness can be extracted from the bandwidth of the resonance. Within the small-load approximation, the frequency shift is independent of whether the sample is applied to the face or to the side of the cylinder. Details of the geometry matter if the viscoelastic properties of the sample are of interest.

Buecking, W.; Du, B.; Turshatov, A.; Koenig, A. M.; Reviakine, I.; Bode, B.; Johannsmann, D. [Institute of Physical Chemistry, Clausthal University of Technology, Arnold-Sommerfeld-Strasse 4, D-38678 Clausthal-Zellerfeld (Germany); Flucon Fluid Control GmbH, Burgstaetter Strasse 6, D-38678 Clausthal-Zellerfeld (Germany); Institute of Physical Chemistry, Clausthal University of Technology, Arnold-Sommerfeld-Strasse 4, D-38678 Clausthal-Zellerfeld (Germany)

2007-07-15

244

Quartz crystal microbalance based on torsional piezoelectric resonators  

NASA Astrophysics Data System (ADS)

A quartz crystal microbalance (QCM) is described, which is based on a torsional resonator, rather than a conventional thickness-shear resonator. Typical applications are measurements of film thickness in the coating industry and monitoring of biofouling. The torsional QCM is about a factor of 100 less sensitive than the conventional QCM. On the other hand, it can probe film thicknesses in the range of hundreds of microns, which is impossible with the conventional QCM due to viscoelastic artifacts. Data acquisition and data analysis proceed in analogy to the conventional QCM. An indicator of the material's softness can be extracted from the bandwidth of the resonance. Within the small-load approximation, the frequency shift is independent of whether the sample is applied to the face or to the side of the cylinder. Details of the geometry matter if the viscoelastic properties of the sample are of interest.

Bücking, W.; Du, B.; Turshatov, A.; König, A. M.; Reviakine, I.; Bode, B.; Johannsmann, D.

2007-07-01

245

Analysis of Fano-line shapes from agile resonant waveguide grating sensors using correlation techniques  

NASA Astrophysics Data System (ADS)

The asymmetric Fano resonance lineshape, resulting from interference between background and a resonant scattering, is archetypal in resonant waveguide grating (RWG) reflectivity. Resonant profile shift resulting from a change of refractive index (from fluid medium or biomolecules at the chip surface) is classically used to perform label-free sensing. Lineshapes are sometimes sampled at discretized "detuning" values to relax instrumental demands, the highest reflectivity element giving a coarse resonance estimate. A finer extraction, needed to increase sensor sensitivity, can be obtained using a correlation approach, correlating the sensed signal to a zero-shifted reference signal. Correlation approach is robust to asymmetry of Fano lineshapes and allows more accurate determination than usual fitting options such as Gaussian or Lorentz shape fitting. Our findings are illustrated with resonance profiles from silicon nitride "chirped" RWGs operated at visible wavelengths. The scheme circumvents the classical but demanding spectral or angular scans: instead of varying angle or wavelength through fragile moving parts or special optics, a RWG structure parameter is varied. Then, the spatial reflectivity profiles of tracks composed of RWGs units with slowly varying filling factor (thus slowly varying resonance condition) are measured under monochromatic conditions. Extracting the resonance location using plain images of these "pixelated" Fano profiles allows multiplex refractive index based sensing with a sensitivity down to 2×10-5 RIU as demonstrated experimentally. This scheme based on a "Peak-tracking chip" demonstrates a new technique for bioarray imaging using a simpler set-up that maintains high performance with cheap lenses.

Bougot-Robin, K.; Wen, W. J.; Benisty, H.

2013-05-01

246

Electroexcitation of the Roper resonance for 1.7enpi+  

Microsoft Academic Search

The helicity amplitudes of the electroexcitation of the Roper resonance are extracted for 1.7

I. G. Aznauryan; V. D. Burkert; W. Kim; G. Adams; M. J. Amaryan; P. Ambrozewicz; M. Anghinolfi; G. Asryan; H. Avakian; H. Bagdasaryan; N. Baillie; J. P. Ball; N. A. Baltzell; S. Barrow; V. Batourine; M. Battaglieri; I. Bedlinskiy; M. Bektasoglu; M. Bellis; N. Benmouna; B. L. Berman; A. S. Biselli; L. Blaszczyk; B. E. Bonner; C. Bookwalter; S. Bouchigny; S. Boiarinov; R. Bradford; D. Branford; W. K. Brooks; S. Bültmann; C. Butuceanu; J. R. Calarco; S. L. Careccia; D. S. Carman; L. Casey; A. Cazes; S. Chen; L. Cheng; P. L. Cole; P. Collins; P. Coltharp; D. Cords; P. Corvisiero; D. Crabb; V. Crede; J. P. Cummings; D. Dale; N. Dashyan; R. De Masi; R. De Vita; E. De Sanctis; P. V. Degtyarenko; H. Denizli; L. Dennis; A. Deur; S. Dhamija; K. V. Dharmawardane; K. S. Dhuga; R. Dickson; C. Djalali; G. E. Dodge; J. Donnelly; D. Doughty; M. Dugger; S. Dytman; O. P. Dzyubak; H. Egiyan; K. S. Egiyan; L. El Fassi; L. Elouadrhiri; P. Eugenio; R. Fatemi; G. Fedotov; G. Feldman; R. J. Feuerbach; T. A. Forest; A. Fradi; H. Funsten; M. Y. Gabrielyan; M. Garçon; G. Gavalian; N. Gevorgyan; G. P. Gilfoyle; K. L. Giovanetti; F. X. Girod; J. T. Goetz; W. Gohn; E. Golovatch; A. Gonenc; C. I. O. Gordon; R. W. Gothe; L. Graham; K. A. Griffioen; M. Guidal; M. Guillo; N. Guler; L. Guo; V. Gyurjyan; C. Hadjidakis; K. Hafidi; K. Hafnaoui; H. Hakobyan; R. S. Hakobyan; C. Hanretty; J. Hardie; N. Hassall; D. Heddle; F. W. Hersman; K. Hicks; I. Hleiqawi; M. Holtrop; C. E. Hyde; Y. Ilieva; D. G. Ireland; B. S. Ishkhanov; E. L. Isupov; M. M. Ito; D. Jenkins; H. S. Jo; J. R. Johnstone; K. Joo; H. G. Juengst; N. Kalantarians; D. Keller; J. D. Kellie; M. Khandaker; K. Y. Kim; A. Klein; F. J. Klein; A. V. Klimenko; M. Kossov; Z. Krahn; L. H. Kramer; V. Kubarovsky; J. Kuhn; S. E. Kuhn; S. V. Kuleshov; V. Kuznetsov; J. Lachniet; J. M. Laget; J. Langheinrich; D. Lawrence; T. Lee; Ji Li; A. C. S. Lima; K. Livingston; H. Y. Lu; K. Lukashin; M. MacCormick; N. Markov; P. Mattione; S. McAleer; B. McKinnon; J. W. C. McNabb; B. A. Mecking; S. Mehrabyan; J. J. Melone; M. D. Mestayer; C. A. Meyer; T. Mibe; K. Mikhailov; R. Minehart; M. Mirazita; R. Miskimen; V. Mokeev; L. Morand; B. Moreno; K. Moriya; S. A. Morrow; M. Moteabbed; J. Mueller; E. Munevar; G. S. Mutchler; P. Nadel-Turonski; R. Nasseripour; S. Niccolai; G. Niculescu; I. Niculescu; B. B. Niczyporuk; M. R. Niroula; R. A. Niyazov; M. Nozar; G. V. O'Rielly; M. Osipenko; A. I. Ostrovidov; E. Pasyuk; C. Paterson; S. Anefalos Pereira; S. A. Philips; J. Pierce; N. Pivnyuk; D. Pocanic; O. Pogorelko; E. Polli; I. Popa; S. Pozdniakov; B. M. Preedom; J. W. Price; Y. Prok; D. Protopopescu; L. M. Qin; B. A. Raue; G. Riccardi; G. Ricco; M. Ripani; B. G. Ritchie; G. Rosner; P. Rossi; D. Rowntree; P. D. Rubin; F. Sabatié; M. S. Saini; J. Salamanca; C. Salgado; J. P. Santoro; V. Sapunenko; D. Schott; R. A. Schumacher; V. S. Serov; Y. G. Sharabian; D. Sharov; J. Shaw; N. V. Shvedunov; A. V. Skabelin; E. S. Smith; L. C. Smith; D. I. Sober; D. Sokhan; A. Stavinsky; S. S. Stepanyan; B. E. Stokes; P. Stoler; I. I. Strakovsky; S. Strauch; R. Suleiman; M. Taiuti; T. Takeuchi; D. J. Tedeschi; A. Tkabladze; S. Tkachenko; L. Todor; C. Tur; M. Ungaro; M. F. Vineyard; A. V. Vlassov; D. P. Watts; L. B. Weinstein; D. P. Weygand; M. Williams; E. Wolin; M. H. Wood; A. Yegneswaran; J. Yun; M. Yurov; L. Zana; B. Zhang; J. Zhang; B. Zhao; Z. W. Zhao

2008-01-01

247

Fast, Accurate Unsupervised Segmentation of 3D Magnetic Resonance Angiography  

Microsoft Academic Search

\\u000a Accurate automatic extraction of a 3D cerebrovascular system from images obtained by time-of-flight (TOF) or phase-contrast\\u000a (PC) magnetic resonance angiography (MRA) is a challenging segmentation problem due to small size objects of interest (blood\\u000a vessels) in each 2D MRA slice and complex surrounding anatomical structures, e.g. fat, bones, or gray and white brain matter.\\u000a We show that due to a

Ayman El-Baz; Georgy Gimel’farb; Ahmed Elnakib; Robert Falk; Mohamed Abou El-Ghar

248

Pressure dependent resonant frequency of micromechanical drumhead resonators  

NASA Astrophysics Data System (ADS)

We examine the relationship between squeeze film effects and resonance frequency in drum-type resonators. We find that the resonance frequency increases linearly with pressure as a result of the additional restoring force contribution from compression of gas within the drum cavity. We demonstrate trapping of the gas by squeeze film effects and geometry. The pressure sensitivity is shown to scale inversely with cavity height and sound radiation is found to be the predominant loss mechanism near and above atmospheric pressure. Drum resonators exhibit linearity and sensitivity suitable to barometry from below 10 Torr up to several atmospheres.

Southworth, D. R.; Craighead, H. G.; Parpia, J. M.

2009-05-01

249

Petal resonator surface coil in spectroscopy by magnetic resonance  

NASA Astrophysics Data System (ADS)

In this work, we present a radio frequency resonator surface coil for Magnetic Resonance Imaging and Spectroscopy based on the magnetron device. We named our RF coil: Petal Resonator Surface (PERES) coil. This resonator coil consists of eight coil petals connected symmetrically all around a central single-loop coil. We previously tested this coil prototype n a General Electric 1.5 T imager and successfully acquired brain images. Based on these encouraging results, we used our coil design on the same MR imager to generate brain spectra. Finally, a MR spectrum of a healthy brain is presented. .

Hidalgo, S.; Rodriguez, A.; Rojas, R.; Sanchez, J.; Reynoso, G.; Barrios, F. A.

2001-10-01

250

Extensive Screening for Edible Herbal Extracts with Potent Scavenging Activity against Superoxide Anions  

Microsoft Academic Search

To search for edible herbal extracts with potent antioxidant activity, we conducted a large scale screening based on the superoxide\\u000a scavenging activity. That is, scavenging activity against superoxide anions were extensively screened from ethanol extracts\\u000a of approximately 1,000 kinds of herbs by applying an electron spin resonance (ESR)-spin trapping method. Among them we chose\\u000a four edible herbal extracts with prominently

Keita Saito; Masahiro Kohno; Fumihiko Yoshizaki; Yoshimi Niwano

2008-01-01

251

Structure of hyperon resonances  

SciTech Connect

Baryons are composite objects. Although this fact has been verified beyond doubt, the authors are far from understanding its internal structure using first principles based on Quantum Chromodynamics (QCD). This theory of strong interactions governs the dynamics of quarks and gluons with which the authors ultimately would like to describe nuclear physics. Any realistic model of baryons should therefore simulate QCD and somehow make connections to nuclear physics. In this work, the authors use a candidate for one such model, the chiral bag model, to examine whether it can offer any valuable insights into the structure of hyperon resonances, especially those that might play important roles in hypernuclear physics. The authors begin by calculating the mass spectrum of negative parity hyperons in this model calculation are discussed and an estimate is made of the magnitude of theoretical uncertainty in the results. After exploring how the masses and the spin-flavor compositions of the hyperon resonances are determined, the authors find a reasonable fit to the mass spectrum. However, a comparison with another model prediction indicates that this alone is insufficient to determine the structure of excited hyperons. Therefore, the authors calculate some strong interaction properties and radiative decay widths of the two lightest hyperon resonances. Both of these quantities are sensitive to the spin-flavor composition of the hyperons and the former are of interest to low energy KN interactions while the latter also test model dependent electromagnetic transition operators. The authors also comment on the complicated structure of the [Lambda](1405) and argue that experimental determination of hyperon radiative widths would provide an ideal probe to explore the structure of excited strange baryons.

Umino, Y.

1992-01-01

252

Electroexcitation of nucleon resonances  

SciTech Connect

We review recent progress in the investigation of the electroexcitation of nucleon resonances, both in experiment and in theory. The most accurate results have been obtained for the electroexcitation amplitudes of the four lowest excited states, which have been measured in a range of Q2 up to 8 and 4.5 GeV2 for the Delta(1232)P33, N(1535)S11 and N(1440)P11, N(1520)D13, respectively. These results have been confronted with calculations based on lattice QCD, large-Nc relations, perturbative QCD (pQCD), and QCD-inspired models. The amplitudes for the Delta(1232) indicate large pion-cloud contributions at low Q2 and don't show any sign of approaching the pQCD regime for Q2<7 GeV2. Measured for the first time, the electroexcitation amplitudes of the Roper resonance, N(1440)P11, provide strong evidence for this state as a predominantly radial excitation of a three-quark (3q) ground state, with additional non-3-quark contributions needed to describe the low Q2 behavior of the amplitudes. The longitudinal transition amplitude for the N(1535)S11 was determined and has become a challenge for quark models. Explanations may require large meson-cloud contributions or alternative representations of this state. The N(1520)D13 clearly shows the rapid changeover from helicity-3/2 dominance at the real photon point to helicity-1/2 dominance at Q2 > 0.5 GeV2, confirming a long-standing prediction of the constituent quark model. The interpretation of the moments of resonance transition form factors in terms of transition transverse charge distributions in infinite momentum frame is presented.

Inna Aznauryan, Volker D. Burkert

2012-01-01

253

Quantum Phase Extraction in Isospectral Electronic Nanostructures  

SciTech Connect

Quantum phase is not a direct observable and is usually determined by interferometric methods. We present a method to map complete electron wave functions, including internal quantum phase information, from measured single-state probability densities. We harness the mathematical discovery of drum-like manifolds bearing different shapes but identical resonances, and construct quantum isospectral nanostructures possessing matching electronic structure but divergent physical structure. Quantum measurement (scanning tunneling microscopy) of these 'quantum drums' [degenerate two-dimensional electron states on the Cu(111) surface confined by individually positioned CO molecules] reveals that isospectrality provides an extra topological degree of freedom enabling robust quantum state transplantation and phase extraction.

Moon, Christopher

2010-04-28

254

Magnetic resonance enterography.  

PubMed

Magnetic resonance (MR) enterography is a targeted examination of the gastrointestinal tract, particularly the small intestine, without nasojejunal intubation (in which case it is referred to as MR enteroclysis). Until recently, MR imaging of the small bowel could not reliably compete with the high-quality small bowel images generated by computed tomography (CT). Now, however, MR enterography is not only a feasible alternative to CT, but may provide superior diagnostic information, specifically with regard to differentiating active, inflammatory disease from chronic, fibrostenotic disease. MR enterography is no longer merely adequate and radiation-free; it is an essential part of the imaging armamentarium. PMID:23182510

Grand, David J; Beland, Michael; Harris, Adam

2013-01-01

255

Nonlinear vibrational resonance  

NASA Astrophysics Data System (ADS)

We examine the nonlinear response of a bistable system driven by a high-frequency force to a low-frequency weak field. It is shown that the rapidly varying temporal oscillation breaks the spatial symmetry of the centrosymmetric potential. This gives rise to a finite nonzero response at the second harmonic of the low-frequency field, which can be optimized by an appropriate choice of vibrational amplitude of the high-frequency field close to that for the linear response. The potential implications of the nonlinear vibrational resonance are analyzed.

Ghosh, Shyamolina; Ray, Deb Shankar

2013-10-01

256

Resonance test system  

DOEpatents

An apparatus (10) for applying at least one load to a specimen (12) according to one embodiment of the invention may comprise a mass (18). An actuator (20) mounted to the specimen (12) and operatively associated with the mass (18) moves the mass (18) along a linear displacement path (22) that is perpendicular to a longitudinal axis of the specimen (12). A control system (26) operatively associated with the actuator (20) operates the actuator (20) to reciprocate the mass (18) along the linear displacement path (22) at a reciprocating frequency, the reciprocating frequency being about equal to a resonance frequency of the specimen (12) in a test configuration.

Musial, Walter (Boulder, CO); White, Darris (Superior, CO)

2011-05-31

257

Supercritical extraction of coal  

Microsoft Academic Search

Supercritical extraction of Wyodak coal was studied by passing various solvents upwards through a 15 gram sample of 12-20 mesh coal. For the high temperature experiments, the coal was heated to 375°C and 425°C in a hot fluidized sand bath. The main solvent used was toluene, while extractions with n-pentane, xylene, methanol, and water were also done. The extract was

Sunol

1982-01-01

258

Coupling superconducting qubits and resonators  

NASA Astrophysics Data System (ADS)

The performance of superconducting qubits has evolved rapidly in recent years, with coherence times now often measured in tens of microseconds. This makes superconducting qubits a promising candidate for a scalable quantum computing architecture and for modeling quantum systems. To realize this potential, consideration must be given to coupling multiple qubits to a system of microwave resonators in a way that balances coherence times, control and readout times, crosstalk, and space constraints. We compare three methods of coupling qubits to resonators: inductive coupling through a shared kinetic inductance with the resonator, capacitive coupling to a voltage antinode, and coupling to a three-dimensional superconducting cavity. We will also present designs and measurements of samples incorporating both inductively and capacitively coupled qubits on the same coplanar resonator. Lastly, we discuss a three-qubit/two-resonator system with one qubit bridging the two resonators that could serve as the building block of a large-scale architecture.

Strand, Joel

2012-02-01

259

DISSIPATIVE DIVERGENCE OF RESONANT ORBITS  

SciTech Connect

A considerable fraction of multi-planet systems discovered by the observational surveys of extrasolar planets reside in mild proximity to first-order mean-motion resonances. However, the relative remoteness of such systems from nominal resonant period ratios (e.g., 2:1, 3:2, and 4:3) has been interpreted as evidence for lack of resonant interactions. Here, we show that a slow divergence away from exact commensurability is a natural outcome of dissipative evolution and demonstrate that libration of critical angles can be maintained tens of percent away from nominal resonance. We construct an analytical theory for the long-term dynamical evolution of dissipated resonant planetary pairs and confirm our calculations numerically. Collectively, our results suggest that a significant fraction of the near-commensurate extrasolar planets are in fact resonant and have undergone significant dissipative evolution.

Batygin, Konstantin [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Morbidelli, Alessandro, E-mail: kbatygin@gps.caltech.edu [Departement Cassiopee, Universite de Nice-Sophia Antipolis, Observatoire de la Cote d'Azur, F-06304 Nice (France)

2013-01-01

260

Determination of ferromagnetic resonance of thin films with coplanar waveguide  

NASA Astrophysics Data System (ADS)

Determination of ferromagnetic resonance of thin films with coplanar waveguide X. Fan, T. Moriyama, R. Cao, John Q. Xiao Department of Physics and Astronomy, University of Delaware, Newark Delaware 19716 USA Recently, Coplanar Waveguide (CPW) has been applied to determine Ferromagnetic Resonance (FMR) of magnetic thin film^1 due to its simple geometry and broadband nature. Compared to the conventional method using reflection in a resonant cavity, CPW should be interpreted by the transmission line theory, taking into account of both transmission and reflection. It has been shown that FMR linewidth extracted from S-matrix after four port calibration ^2 differs from that extracted from transmission only, which neglects the impedance mismatch effect. However, the four port calibration is rather complex and tedious. In this presentation, we introduce a new method to extract FMR spectrum without performing four port calibration. We use both transmission and reflection signals, and consider the impedance mismatch, We will demonstrate the difference between these two methods are negligibly small. 1. Y. Ding, T. J. Klemmer, T. M. Crawford, J. Appl. Phys. 96, 2969, 2004 2. C. Bilzer, T. Devolder, P. Crozat, J. Appl. Phys. 101, 074505, 2007

Fan, Xin; Moriyama, Takahiro; Cao, Rong; Xiao, John

2008-03-01

261

Extensive screening for herbal extracts with potent antioxidant properties  

PubMed Central

This paper summarizes our research for herbal extracts with potent antioxidant activity obtained from a large scale screening based on superoxide radical (O2•?) scavenging activity followed by characterization of antioxidant properties. Firstly, scavenging activity against O2•? was extensively screened from ethanol extracts of approximately 1000 kinds of herbs by applying an electron spin resonance (ESR)-spin trapping method, and we chose four edible herbal extracts with prominently potent ability to scavenge O2•?. They are the extracts from Punica granatum (Peel), Syzygium aromaticum (Bud), Mangifera indica (Kernel), and Phyllanthus emblica (Fruit). These extracts were further examined to determine if they also scavenge hydroxyl radical (•OH), by applying the ESR spin-trapping method, and if they have heat resistance as a desirable characteristic feature. Experiments with the Fenton reaction and photolysis of H2O2 induced by UV irradiation demonstrated that all four extracts have potent ability to directly scavenge •OH. Furthermore, the scavenging activities against O2•? and •OH of the extracts of P. granatum (peel), M. indica (kernel) and P. emblica (fruit) proved to be heat-resistant. The results of the review might give useful information when choosing a potent antioxidant as a foodstuff. For instance, the four herbal extracts chosen from extensive screening possess desirable antioxidant properties. In particular, the extracts of the aforementioned three herbs are expected to be suitable for food processing in which thermal devices are used, because of their heat resistance.

Niwano, Yoshimi; Saito, Keita; Yoshizaki, Fumihiko; Kohno, Masahiro; Ozawa, Toshihiko

2011-01-01

262

Resonance Pacemakers in Excitable Media  

NASA Astrophysics Data System (ADS)

Chemical waves are initiated in an excitable medium by resonance with local periodic forcing of the excitability. Experiments are carried out with a photosensitive Belousov-Zhabotinsky medium, in which the excitability is varied according to the intensity of the imposed illumination. Complex resonance patterns are exhibited as a function of the amplitude and frequency of the forcing. Local resonance-induced wave initiation transforms the medium globally from a quiescent excitable steady state to a periodic state of successive traveling waves.

Chigwada, Tabitha Ruvarashe; Parmananda, P.; Showalter, Kenneth

2006-06-01

263

Resonating microbridge mass flow sensor  

Microsoft Academic Search

A resonating microbridge mass flow sensor with a frequency output is presented, based on standard IC and thin-film technologies, and on front-side anisotropic etching. The operation, realization, theory and experiments are described. The sensitivity is compared with that of a resonating membrane prototype. Preliminary results show a base resonance frequency of 85 kHz at a temperature elevation of the microbridge

Siebe Bouwstra; Rob Legtenberg; Harrie A. C. Tilmans; Miko Elwenspoek

1990-01-01

264

Spectra of resonance surface photoionization  

SciTech Connect

The theory of nonactivated electron transfer between atoms interacting reasonantly with coherent radiation and a metal surface is developed. The spectral resonances in photoabsorption and surface photoionization are found to be related to nonlinear interference effects in the interaction between discrete atomic levels and the continuum formed by the quasi-continuous electron spectrum of a normal metal. The asymmetry in the resonance surface photoionization spectrum is shown to have a shape typical of the Fano autoionization resonances. 18 refs.

Antsiferov, V.V.; Smirnov, G.I.; Telegin, G.G. [Budker Nuclear Physics Institute, Novosibirsk (Russian Federation)

1995-09-01

265

Coupled resonator vertical cavity laser  

SciTech Connect

The monolithic integration of coupled resonators within a vertical cavity laser opens up new possibilities due to the unique ability to tailor the interaction between the cavities. The authors report the first electrically injected coupled resonator vertical-cavity laser diode and demonstrate novel characteristics arising from the cavity coupling, including methods for external modulation of the laser. A coupled mode theory is used model the output modulation of the coupled resonator vertical cavity laser.

Choquette, K.D.; Chow, W.W.; Hou, H.Q.; Geib, K.M.; Hammons, B.E.

1998-01-01

266

Experiments with a quartz resonator  

NASA Astrophysics Data System (ADS)

Experiments with a quartz resonator are described: (i) the frequency response, the quality factor, and the transient processes; (ii) the temperature dependence of the resonance frequency; and (iii) the parameters of the equivalent impedance. A popular quartz resonator designed for generating oscillations of frequency 32?768 Hz (= 215) serves as an example. A new data-acquisition system from PASCO Scientific is used for the measurements. The experiments employ 1 ppm frequency resolution, but are well suited for undergraduate laboratories.

Kraftmakher, Yaakov

2013-09-01

267

Experimental investigation of stochastic resonance  

NASA Astrophysics Data System (ADS)

We report the experimental evidence of Stochastic Resonance in the polarized emission of a semiconductor laser. We give for the first time in a real system a complete characterization of the phenomenon based on the residence times probability density, with quantitative agreement with existing theories. By using an accurate choice of the indicator, we also provide a clear evidence of the bona fide resonance. Moreover, we are able to introduce and investigate for the first time a Three-state Stochastic Resonance. .

Barbay, Sylvain; Giacomelli, Giovanni; Marin, Francesco; Rabbiosi, Ivan; Voignier, Vincent

2000-02-01

268

Luminescence resonance energy transfer  

SciTech Connect

Fluorescence resonance energy transfer (FRET), in which a fluorescent donor molecule transfers energy via a nonradiative dipole-dipole interaction to an acceptor molecule (which is usually a fluorescent molecule), is a standard spectroscopic technique for measuring distances in the 10-70 Angstrom range. We have used a luminescent europium chelate as donor and an organic dye, CY-5, as acceptor. This luminescence resonance energy transfer (LRET) has several advantages over the more conventional FRET. The distance at which 50% of the energy is transferred (R[sub 0]) is large, 70 [angstrom]; the donor lifetime is single exponential and long (0.63 ms in H[sub 2]O; 2.5 ms in D[sub 2]O), making lifetime measurements facile and highly accurate; the orientation dependence (k[sup 2]) of energy transfer is minimized by the donor's multiple electronic transitions and long lifetime, limiting uncertainty in the measured distance due to orientation effects to [+-]12% in the worst case; the sensitized emission of the acceptor can be measured with little or no interfering background, yielding a >50-fold improvement in signal to background over standard donor-acceptor pairs and enabling distances several times R[sub 0] to be measured. 13 refs., 4 figs.

Selvin, P.R.; Rana, T.M.; Hearst, J.E. (Univ. of California, Berkeley, CA (United States) Lawrence Berkeley Lab., CA (United States))

1994-06-29

269

Carbon nanotube mechanical resonators  

NASA Astrophysics Data System (ADS)

Nano-electromechanical systems (NEMS) make use of electrically induced mechanical motion and vice versa. Carbon nanotubes are ideal building blocks of NEMS because of their unique (mechanical) properties and their low mass. This puts them in an unexplored regime of motion which approaches the fundamental detection limit set by quantum mechanics. At room temperature, we use mixing techniques to probe the bending-mode vibration of a suspended carbon nanotube; the gate voltage strains the carbon nanotube and thereby tunes the frequency. At low temperatures, mechanical vibrations are actuated by a nearby antenna and a record high Q-value of 150000 at a resonance frequency of 300 MHz is achieved. Electron tunneling and mechanical motion are strongly coupled resulting in single- electron tuning oscillations of the mechanical frequency and in energy transfer to the electrons causing mechanical damping. Strikingly, we also observe that a d.c. current through the nanotube spontaneously drives the mechanical resonator, exerting a force that is synchronized with the high-frequency vibrations.

van der Zant, Herre

2010-03-01

270

Ion cyclotron resonance cell  

DOEpatents

An ion cyclotron resonance cell is disclosed having two adjacent sections separated by a center trapping plate. The first section is defined by the center trapping plate, a first end trapping plate, and excitation and detector electrodes. The second section includes a second end trapping plate spaced apart from the center plate, a mirror, and an analyzer. The analyzer includes a wavelength-selective light detector, such as a detector incorporating an acousto-optical device (AOD) and a photodetector. One or more ion guides, grounded plates with holes for the ion beam, are positioned within the vacuum chamber of the mass spectrometer between the ion source and the cell. After ions are trapped and analyzed by ion cyclotron resonance techniques in the first section, the ions of interest are selected according to their mass and passed into the second section for optical spectroscopic studies. The trapped ions are excited by light from a laser and caused thereby to fluoresce. The fluorescent light emitted by the excited ions is reflected by the mirror and directed onto the detector. The AOD is scanned, and the photodetector output is recorded and analyzed. The ions remain in the second section for an extended period, enabling multiple studies to be carried out on the same ensemble of ions. 5 figs.

Weller, R.R.

1995-02-14

271

nuclear magnetic resonance gyroscope  

SciTech Connect

A nuclear magnetic resonance gyroscope which derives angular rotation thereof from the phases of precessing nuclear moments utilizes a single-resonance cell situated in the center of a uniform DC magnetic field. The field is generated by current flow through a circular array of coils between parallel plates. It also utilizes a pump and read-out beam and associated electronics for signal processing and control. Encapsulated in the cell for sensing rotation are odd isotopes of Mercury Hg/sup 199/ and Hg/sup 201/. Unpolarized intensity modulated light from a pump lamp is directed by lenses to a linear polarizer, quarter wave plate combination producing circularly polarized light. The circularly polarized light is reflected by a mirror to the cell transverse to the field for optical pumping of the isotopes. Unpolarized light from a readout lamp is directed by lenses to another linear polarizer. The linearly polarized light is reflected by another mirror to the cell transverse to the field and orthogonal to the pump lamp light. The linear light after transversing the cell strikes an analyzer where it is converted to an intensity-modulated light. The modulated light is detected by a photodiode processed and utilized as feedback to control the field and pump lamp excitation and readout of angular displacement.

Karwacki, F. A.; Griffin, J.

1985-04-02

272

Compact biaxial micromachined resonant accelerometer  

NASA Astrophysics Data System (ADS)

This paper presents a biaxial silicon resonant microaccelerometer characterized by a high sensitivity and a low cross-axis sensitivity. The device has a detection structure with a single inertial mass and two pairs of resonating beams allowing for the simultaneous differential measurement of acceleration acting along two different axes. The design of the accelerometer and in particular the geometrical configuration of the resonating elements is analytically optimized and finalized through finite element simulations. Experimental results on a fabricated device demonstrate a mean differential sensitivity of 250 Hz?g-1 at a polarization voltage of 4 V, around a resonance frequency of 84 kHz.

Caspani, Alessandro; Comi, Claudia; Corigliano, Alberto; Langfelder, Giacomo; Tocchio, Alessandro

2013-10-01

273

Fano resonances in nanoscale structures  

SciTech Connect

Modern nanotechnology allows one to scale down various important devices (sensors, chips, fibers, etc.) and thus opens up new horizons for their applications. The efficiency of most of them is based on fundamental physical phenomena, such as transport of wave excitations and resonances. Short propagation distances make phase-coherent processes of waves important. Often the scattering of waves involves propagation along different paths and, as a consequence, results in interference phenomena, where constructive interference corresponds to resonant enhancement and destructive interference to resonant suppression of the transmission. Recently, a variety of experimental and theoretical work has revealed such patterns in different physical settings. The purpose of this review is to relate resonant scattering to Fano resonances, known from atomic physics. One of the main features of the Fano resonance is its asymmetric line profile. The asymmetry originates from a close coexistence of resonant transmission and resonant reflection and can be reduced to the interaction of a discrete (localized) state with a continuum of propagation modes. The basic concepts of Fano resonances are introduced, their geometrical and/or dynamical origin are explained, and theoretical and experimental studies of light propagation in photonic devices, charge transport through quantum dots, plasmon scattering in Josephson-junction networks, and matter-wave scattering in ultracold atom systems, among others are reviewed.

Miroshnichenko, Andrey E.; Flach, Sergej; Kivshar, Yuri S. [Nonlinear Physics Centre and Centre for Ultrahigh Bandwidth Devices for Optical Systems (CUDOS), Research School of Physics and Engineering, Australian National University, Canberra, Australian Capital Territory 0200 (Australia); Max-Planck-Institut fuer Physik Komplexer Systeme, Noethnitzer Strasse 38, D-01187 Dresden (Germany); Nonlinear Physics Centre and Centre for Ultrahigh Bandwidth Devices for Optical Systems (CUDOS), Research School of Physics and Engineering, Australian National University, Canberra, Australian Capital Territory 0200 (Australia)

2010-07-15

274

Unfolding the Second Riemann sheet with Padé Approximants: hunting resonance poles  

NASA Astrophysics Data System (ADS)

Based on the mathematically well defined Padé Theory, a theoretically safe new procedure for the extraction of the pole mass and width of resonances is proposed. In particular, thanks to the Montessus de Ballore theorem we are able to unfold the Second Riemann sheet of a amplitude to search the position of the resonant pole in the complex plane. The main advantage of that method is it systematical and model-independent treatment of the prediction and the corresponding errors of the approximation.

Masjuan, Pere

2010-10-01

275

Internal structure of the Lambda(1405) resonance probed in chiral unitary amplitude  

Microsoft Academic Search

The internal structure of the resonant Lambda(1405) state is investigated based on meson-baryon coupled-channels chiral dynamics. We evaluate Lambda(1405) form factors which are extracted from current-coupled scattering amplitudes in meson-baryon degrees of freedom. Using several probe currents and channel decomposition, we find that the resonant Lambda(1405) state is dominantly composed of widely spread Kbar around N, with escaping pi Sigma

Takayasu Sekihara; Tetsuo Hyodo; Daisuke Jido

2011-01-01

276

Effect of three-pion unitarity on resonance poles from heavy meson decays  

SciTech Connect

We study the final state interaction in 3{pi} decay of meson resonances at the Excited Baryon Analysis Center (EBAC) of JLab. We apply the dynamical coupled-channels formulation which has been extensively used by EBAC to extract N{sup *} information. The formulation satisfies the 3{pi} unitarity condition which has been missed in the existing works with the isobar models. We report the effect of the 3{pi} unitarity on the meson resonance pole positions and Dalitz plot.

Nakamura, Satoshi X. [Excited Baryon Analysis Center, Jefferson Laboratory, Newport News, Virginia 23606 (United States)

2011-10-21

277

Effect of three-pion unitarity on resonance poles from heavy meson decays  

SciTech Connect

We study the final state interaction in 3-pion decay of meson resonances at the Excited Baryon Analysis Center (EBAC) of JLab. We apply the dynamical coupled-channels formulation which has been extensively used by EBAC to extract N* information. The formulation satisfies the 3-pion unitarity condition which has been missed in the existing works with the isobar models. We report the effect of the 3-pion unitarity on the meson resonance pole positions and Dalitz plot.

Satoshi X. Nakamura

2011-10-01

278

The development of an electron cyclotron resonance ion source for the heavy ion research facility in Lanzhou  

Microsoft Academic Search

A new working condition for an electron cyclotron resonance (ECR) source for the heavy ion research facility in Lanzhou (HIRFL) is reported. This condition is based on the full use of the secondary electrons injected into the source plasma near the extraction region of source cavity, and allows ion extraction from a denser plasma. A new magnetic field configuration which

Liu Zhanwen; Zhang Wen; Zhao Hongwei; Yuan Ping; Zhang Xuezhen; Guo Xiaohong; Zhang Zimin; Li Xixia; Wang Hui; Feng Yucheng; Li Jinyu; Gao Jiyuan; Ma Baohua; Lei Hailiang; Zhou Sixin; Wang Yifang; Wei Baowen

1998-01-01

279

Localized ferromagnetic resonance using Magnetic Resonance Force Microscopy  

Microsoft Academic Search

Magnetic Resonance Force Microscopy (MRFM) is a novel approach to scanned probe imaging, combining the advantages of Magnetic Resonance Imaging (MRI) with Scanning Probe Microscopy (SPM) [1]. It has extremely high sensitivity that has demonstrated detection of individual electron spins [2] and small numbers of nuclear spins [3]. Here we describe our MRFM experiments on Ferromagnetic thin film structures. Unlike

Jongjoo Kim

2008-01-01

280

Collisional activation of ions by off-resonance irradiation in ion cyclotron resonance spectrometry  

NASA Astrophysics Data System (ADS)

Collisional activation of ions in the ion cyclotron resonance (ICR) cell by short off-resonance burst irradiation (ORBI) was studied by time-resolved photodissociation of the meta-bromotoluene radical cation. Off-resonance chirp or single-frequency burst was applied for 2 ms to the probe ion in the presence of Ar buffer gas. The amount of internal energy imparted to the probe ion by collision under ORBI was precisely determined by time-resolved photodissociation spectroscopy. The rate of unimolecular dissociation of the probe ion following the photolysis at 532 nm was measured by monitoring the real-time appearance of the C7H7+ product ion. The internal energy of the probe ion was extracted from the known rate-energy curve. To help understand the collisional activation of an ion under ORBI, we simulated the radial trajectory of the ion using Green's method. The calculated radial kinetic energy was converted to the collision energy in the center-of-mass frame, and the collision frequency was estimated by using a reactive hard-sphere collision model with an ion-induced dipole potential. Both experiments and trajectory simulations suggest that chirp irradiation leads to less collisional activation of ions than other waveforms.

Shin, Seung Koo; Han, Seung-Jin; Seo, Jongcheol

2009-06-01

281

Proton Spin Structure in the Resonance Region  

SciTech Connect

The RSS collaboration has measured the spin structure functions g{sub 1} and g{sub 2} of the proton at Jefferson Lab using the lab's polarized electron beam, the Hall C HMS spectrometer and the UVa polarized solid target. The asymmetries A{sub parallel} and A{sub perp} were measured at the elastic peak and in the region of the nucleon resonances (1.085 GeV < W < 1.910 GeV) at an average four momentum transfer of Q{sup 2} = 1.3 GeV{sup 2}. The extracted spin structure functions and their kinematic dependence make a significant contribution in the study of higher-twist effects and polarized duality tests.

F. R. Wesselmann; K. Slifer; S. Tajima; A. Aghalaryan; A. Ahmidouch; R. Asaturyan; F. Bloch; W. Boeglin; P. Bosted; C. Carasco; R. Carlini; J. Cha; J. P. Chen; M. E. Christy; L. Cole; L. Coman; D. Crabb; S. Danagoulian; D. Day; J. Dunne; M. Elaasar; R. Ent; H. Fenker; E. Frlez; L. Gan; D. Gaskell; J. Gomez; B. Hu; M. K. Jones; J. Jourdan; C. Keith; C. E. Keppel; M. Khandaker; A. Klein; L. Kramer; Y. Liang; J. Lichtenstadt; R. Lindgren; D. Mack; P. McKee; D. McNulty; D. Meekins; H. Mkrtchyan; R. Nasseripour; I. Niculescu; K. Normand; B. Norum; D. Pocanic; Y. Prok; B. Raue; J. Reinhold; J. Roche; D. Rohe; O. A. Rondon; N. Savvinov; B. Sawatzky; M. Seely; I. Sick; C. Smith; G. Smith; S. Stepanyan; L. Tang; G. Testa; W. Vulcan; K. Wang; G. Warren; S. Wood; C. Yan; L. Yuan; Junho Yun; Markus Zeier; Hong Guo Zhu

2006-10-11

282

Magnetic resonance studies of dissolving particulate solids.  

PubMed

Magnetic resonance methods have been used to elucidate the internal pore structure of particulate solids, in particular detergent tablets. Such information is essential to a comprehensive understanding of the dissolution characteristics of these materials and how this property is related to processing conditions during tablet formation. In particular 3-D images of porosity are produced and 2-D self-diffusion maps are acquired as a function of observation time, which enables pore size to be quantified as a function of position via the extracted surface-to-volume ratio of the pore space. These properties are determined as a function of processing parameters, in particular the compression force used in tablet formation. PMID:12850743

Johns, M L; Gladden, L F

283

Glomalin extraction and measurement  

Microsoft Academic Search

We investigated extraction from soil of glomalin, a glycoprotein produced by arbuscular mycorrhizal fungi, and we examined its measurement. The most commonly used protocols for extracting glomalin require autoclaving of soil in citrate solution, followed by centrifugation to separate the supernatant, and then measurement by either Bradford protein assay or enzyme-linked immunosorbent assay (ELISA). We found that lengthening the time

David P. Janos; Sara Garamszegi; Bray Beltran

2008-01-01

284

Feature Extraction Assessment Study.  

National Technical Information Service (NTIS)

The purpose of the feature extraction assessment study (FEAS) is to assess the degree to which the DMA feature extraction process can be automated by 1985. The major conclusion of the study is that given the state-of-the-art in image understanding and pat...

M. J. Carlotto V. T. Tom G. K. Wallace

1984-01-01

285

Yeast DNA Extraction  

NSDL National Science Digital Library

This laboratory exercise is designed to show learners how DNA can easily be extracted from yeast using simple materials. Use this experiment to supplement any unit on genetics and to demonstrate how scientists study DNA. Adult supervision is recommended. This resource guide includes tips and suggestions for instructors as well as other DNA extraction experiments and a chart for learners to answer questions.

Hays, Lana

2009-01-01

286

Extractive Metallurgy of Beryllium  

Microsoft Academic Search

A comprehensive review of the extractive metallurgy of beryllium is presented. Due to the strategic importance and element of secrecy surrounding the metal, any open literature on beryllium is rather limited. However, this review has been made to cover all important aspects of beryllium extraction technology namely, resources of the metal; processing of ores; reduction of fluoride and oxide to

C. K. GUPTA; S. SAHA

2002-01-01

287

Extractive Metallurgy of Beryllium  

Microsoft Academic Search

A comprehensive review of the extractive metallurgy of beryllium is presented. Due to the strategic importance and element of secrecy surrounding the metal, any open literature on beryllium is rather limited. However, this review has been made to cover all important aspects of beryllium extraction technology namely, resources of the metal; processing of ores; reduction of fluoride and oxide to

C. K. GUPTA; S. SAHA

2001-01-01

288

Resonance contributions to Hanbury-Brown{endash}Twiss correlation radii  

SciTech Connect

We study the effect of resonance decays on intensity interferometry for heavy ion collisions. Collective expansion of the source leads to a dependence of the two-particle correlation function on the pair momentum {bold K}. This opens the possibility to reconstruct the dynamics of the source from the {bold K} dependence of the measured Hanburg-Brown{endash}Twiss (HBT) radii. Here we address the question to what extent resonance decays can fake such a flow signal. Within a simple parametrization for the emission function we present a comprehensive analysis of the interplay of flow and resonance decays on the one- and two-particle spectra. We discuss in detail the non-Gaussian features of the correlation function introduced by long-lived resonances and the resulting problems in extracting meaningful HBT radii. We propose to define them in terms of the second-order q moments of the correlator C({bold q},{bold K}). We show that this yields a more reliable characterisation of the correlator in terms of its width and the correlation strength {lambda} than other commonly used fit procedures. The normalized fourth-order q moments (kurtosis) provide a quantitative measure for the non-Gaussian features of the correlator. At least for the class of models studied here, the kurtosis helps separating effects from expansion flow and resonance decays, and provides the cleanest signal to distinguish between scenarios with and without transverse flow. {copyright} {ital 1997} {ital The American Physical Society}

Wiedemann, U.A. [Institut fuer Theoretische Physik, Universitaet Regensburg, D-93040 Regensburg (Germany); Heinz, U. [Institut fuer Theoretische Physik, Universitaet Regensburg, D-93040 Regensburg (Germany)]|[CERN/TH, CH-1211 Geneva 23 (Switzerland)

1997-12-01

289

Weed extraction system, method  

US Patent & Trademark Office Database

A system and method for providing weed extraction so Industrial, Commercial and Home users (ICAHUs) can assure that unwanted weeds can be easily and effectively extracted. The system and method allows ICAHUs to work safely and efficiently and to extract weeds by using a hand-held device that can easily penetrate the ground around weeds, secure the unwanted weed, and aid the user in extracting the weed from the ground. ICAHUs can easily operate the levers of the device which operate jaws to secure to weeds. Specialized debris passages in the jaws of the device allow for debris to be passed through the jaws of the device which allow to for continued use and a greatly reduced need to clean the device during use. The method comprises a system in which unwanted weeds may be easily secured and extracted by the user without an increased risk of accidents or without unnecessary steps or procedures for cleaning.

Carter; Larry (Makawao, HI)

2013-06-25

290

Resonant power supplies - Their history and status  

Microsoft Academic Search

A development history and current status evaluation are furnished for resonant power supplies, in which an input dc voltage is applied through controlled switches to an inductance-capacitance resonant circuit. Attention is given to single- and double-switch resonant converters, series and parallel resonant converters, and the advantages and disadvantages of all such resonant devices, as well as to such methods of

P. R. K. Chetty

1992-01-01

291

Simple and Inexpensive Classroom Demonstrations of Nuclear Magnetic Resonance and Magnetic Resonance Imaging.  

ERIC Educational Resources Information Center

Describes a set of simple, inexpensive, classical demonstrations of nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) principles that illustrate the resonance condition associated with magnetic dipoles and the dependence of the resonance frequency on environment. (WRM)

Olson, Joel A.; Nordell, Karen J.; Chesnik, Marla A.; Landis, Clark R.; Ellis, Arthur B.; Rzchowski, M. S.; Condren, S. Michael; Lisensky, George C.

2000-01-01

292

Distribution behavior of astatine: Solvent extraction and back extraction  

Microsoft Academic Search

The distribution behavior of astatine was studied at tracer concentrations and over a wide range of carrier iodide concentration in both solvent extraction and back extraction processes. Astatine compounds were extracted instantly into the organic solvent, CS2 from the carrier free and carrier iodide containing solutions. Back extraction of astatine with various NaOH solutions followed by solvent extraction caused the

M. S. Sultana; A. Toyoshima; N. Takahashi; H. Baba

2001-01-01

293

Coherent Nuclear Resonance Fluorescence  

NASA Astrophysics Data System (ADS)

For a long time, the impact of ideas with respect to coherency and scattering on the art and science of Mössbauer spectroscopy was not very essential. The main line of development of Mössbauer experiments rested in the frame of absorption spectroscopy. Mössbauer physicists dealt mostly with absorption spectra taken either in traditional transmission experiments or in measurements of the conversion electron yield. For the interpretation and description of these spectra, it was appropriate to use the picture of interaction of ?-quantum with an individual nucleus where the nuclear resonant absorption cross-section was applied. The coherent properties of radiation and those of the interaction mechanism were not explicitly involved in these studies. In the meantime, coherent phenomena with Mössbauer ?-rays were thoroughly investigated, starting soon after Mössbauer's discovery. The present paper is aimed to illuminate this side of the Mössbauer story.

Smirnov, G. V.

294

Resonance in rarefied gases  

NASA Astrophysics Data System (ADS)

Dispersion and damping of ultrasound waves are a standard test for mathematical models of rarefied gas flows. Normally, one considers waves in semi-infinite systems in relatively large distance of the source. For a more complete picture, ultrasound propagation in finite closed systems of length L is studied by means of several models for rarefied gas flows: the Navier-Stokes-Fourier equations, Grad's 13 moment equations, the regularized 13 moment equations, and the Burnett equations. All systems of equations are considered in simple 1-D geometry with their appropriate jump and slip boundary conditions. Damping and resonance are studied in dependence of frequency and length. For small L, all wave modes contribute to the solution.

Struchtrup, Henning

2012-11-01

295

Fullerenes in electron cyclotron resonance ion sources  

SciTech Connect

Fullerene plasmas and beams have been produced in our electron cyclotron resonance ion sources (ECRIS) originally designed for other purposes. The ATOMKI-ECRIS is a traditional ion source with solenoid mirror coils to generate highly charged ions. The variable frequencies NIRS-KEI-1 and NIRS-KEI-2 are ECR ion sources built from permanent magnets and specialized for the production of carbon beams. The paper summarizes the experiments and results obtained by these facilities with fullerenes. Continuous effort has been made to get the highest C{sub 60} beam intensities. Surprisingly, the best result was obtained by moving the C{sub 60} oven deep inside the plasma chamber, very close to the resonance zone. Record intensity singly and doubly charged fullerene beams were obtained (600 and 1600 nA, respectively) at lower C{sub 60} material consumption. Fullerene derivatives were also produced. We mixed fullerenes with other plasmas (N, Fe) with the aim of making new materials. Nitrogen encapsulated fullerenes (mass: 720+14=734) were successfully produced. In the case of iron, two methods (ferrocene, oven) were tested. Molecules with mass of 720+56=776 were detected in the extracted beam spectra.

Biri, S.; Fekete, E.; Kitagawa, A.; Muramatsu, M.; Janossy, A.; Palinkas, J. [Institute of Nuclear Research (ATOMKI), H-4026 Debrecen, Bem ter 18/C (Hungary); National Institute for Radiological Sciences (NIRS), 4-9-1 Anagawa, Inage, Chiba 263-8555 (Japan); Department of Experimental Physics, Technical University of Budapest, H-1521 Budapest, P.O. Box 91 (Hungary); Department of Experimental Physics, University of Debrecen, H-4026 Debrecen, Bem ter 18/A (Hungary)

2006-03-15

296

Baryon Spectroscopy and Resonances  

SciTech Connect

A short review of current efforts to determine the highly excited state spectrum of QCD, and in particular baryons, using lattice QCD techniques is presented. The determination of the highly excited spectrum of QCD is a major theoretical and experimental challenge. The experimental investigation of the excited baryon spectrum has been a long-standing element of the hadronic-physics program, an important component of which is the search for so-called 'missing resonances', baryonic states predicted by the quark model based on three constituent quarks but which have not yet been observed experimentally. Should such states not be found, it may indicate that the baryon spectrum can be modeled with fewer effective degrees of freedom, such as in quark-diquark models. In the past decade, there has been an extensive program to collect data on electromagnetic production of one and two mesons at Jefferson Lab, MIT-Bates, LEGS, MAMI, ELSA, and GRAAL. To analyze these data, and thereby refine our knowledge of the baryon spectrum, a variety of physics analysis models have been developed at Bonn, George Washington University, Jefferson Laboratory and Mainz. To provide a theoretical determination and interpretation of the spectrum, ab initio computations within lattice QCD have been used. Historically, the calculation of the masses of the lowest-lying states, for both baryons and mesons, has been a benchmark calculation of this discretized, finite-volume computational approach, where the aim is well-understood control over the various systematic errors that enter into a calculation; for a recent review. However, there is now increasing effort aimed at calculating the excited states of the theory, with several groups presenting investigations of the low-lying excited baryon spectrum, using a variety of discretizations, numbers of quark flavors, interpolating operators, and fitting methodologies. Some aspects of these calculations remain unresolved and are the subject of intense effort, notably the ordering of the Roper resonance in the low-lying Nucleon spectrum.

Robert Edwards

2011-12-01

297

The Resonance Theory of Hearing  

Microsoft Academic Search

Mr. ACKERMANN (NATURE, May 20, p. 649) is probably correct when he states that the first incoming sound wave sets all the resonators of the ear temporarily in vibration, and also, that as the sound waves continue the vibrating resonators decrease in number until only those are left in motion that are executing either sympathetic or forced vibration in time

H. Hartridge

1922-01-01

298

Stripping to Isobaric Analog Resonances  

Microsoft Academic Search

The form factor for the stripping distorted-wave Born-approximation amplitude to isobaric analog resonances is derived using a fine-structure theory of these resonances. It is found that the corrections due to compound-nucleus mixing are small. Using the derived form factor, the spectroscopic factors are calculated for the reaction Mo92(He3, d)Tc93.

D. Agassi; N. Auerbach; A. Moalem

1972-01-01

299

Nonlinear resonance. [Univ. of Washington  

SciTech Connect

A brief summary of progress is given in the following areas: sustained resonance in non-Hamiltonian systems, two simultaneous sustained resonances, bursting oscillators, and the interaction of a strong shock with weak disturbances. Work will encompass linearly unstable, weakly nonlinear waves.

Not Available

1993-01-01

300

Resonating feathers produce courtship song  

PubMed Central

Male Club-winged Manakins, Machaeropterus deliciosus (Aves: Pipridae), produce a sustained tonal sound with specialized wing feathers. The fundamental frequency of the sound produced in nature is approximately 1500 Hz and is hypothesized to result from excitation of resonance in the feathers' hypertrophied shafts. We used laser Doppler vibrometry to determine the resonant properties of male Club-winged Manakin's wing feathers, as well as those of two unspecialized manakin species. The modified wing feathers exhibit a response peak near 1500 Hz, and unusually high Q-values (a measure of resonant tuning) for biological objects (Q up to 27). The unmodified wing feathers of the Club-winged Manakin do not exhibit strong resonant properties when measured in isolation. However, when measured still attached to the modified feathers (nine feathers held adjacent by an intact ligament), they resonate together as a unit near 1500 Hz, and the wing produces a second harmonic of similar or greater amplitude than the fundamental. The feathers of the control species also exhibit resonant peaks around 1500 Hz, but these are significantly weaker, the wing does not resonate as a unit and no harmonics are produced. These results lend critical support to the resonant stridulation hypothesis of sound production in M. deliciosus.

Bostwick, Kimberly S.; Elias, Damian O.; Mason, Andrew; Montealegre-Z, Fernando

2010-01-01

301

Matryoshka locally resonant sonic crystal  

Microsoft Academic Search

The results of numerical modelling of sonic crystals with resonant array elements are reported. The investigated resonant elements include plain slotted cylinders as well as various their combinations, in particular, Russian doll or Matryoshka configurations. The acoustic band structure and transmission characteristics of such systems have been computed with the use of finite element methods. The general concept of a

Daniel P. Elford; Luke Chalmers; Feodor V. Kusmartsev; Gerry M. Swallowe

2011-01-01

302

Improved Ring-Supported Resonators.  

National Technical Information Service (NTIS)

We have investigated some improved ring-supported (r-s) resonators. These resonators show promise of providing high precision frequencies for a wide temperature range and static and dynamic forces encountered in the field. In this paper, we report the exp...

M. Nakazawa H. Ito

1982-01-01

303

Electromechanical Resonators from Graphene Sheets  

Microsoft Academic Search

Nanoelectromechanical systems were fabricated from single- and multilayer graphene sheets by mechanically exfoliating thin sheets from graphite over trenches in silicon oxide. Vibrations with fundamental resonant frequencies in the megahertz range are actuated either optically or electrically and detected optically by interferometry. We demonstrate room-temperature charge sensitivities down to 8 × 10–4 electrons per root hertz. The thinnest resonator consists

J. Scott Bunch; Arend M. Van der Zande; Scott S. Verbridge; Ian W. Frank; David M. Tanenbaum; Jeevak M. Parpia; Harold G. Craighead; Paul L. McEuen

2007-01-01

304

Negative-Frequency Resonant Radiation  

NASA Astrophysics Data System (ADS)

Optical solitons or solitonlike states shed light to blueshifted frequencies through a resonant emission process. We predict a mechanism by which a second propagating mode is generated. This mode, called negative resonant radiation, originates from the coupling of the soliton mode to the negative-frequency branch of the dispersion relation. Measurements in both bulk media and photonic-crystal fibers confirm our predictions.

Rubino, E.; McLenaghan, J.; Kehr, S. C.; Belgiorno, F.; Townsend, D.; Rohr, S.; Kuklewicz, C. E.; Leonhardt, U.; König, F.; Faccio, D.

2012-06-01

305

Resonances of sandwiched optical antenna  

Microsoft Academic Search

We calculate the resonant properties of the sandwiched triangle and bowtie antennas using finite difference time domain technique and compare with one-layer structures. The sandwiched antennas possess two tunable resonances corresponding to the symmetric and antisymmetric modes for dipole excitation, which can be understood by the hybridization of the plasmons supported by the two golden layers of the antennas. We

Lisheng Wang; Jiasen Zhang; Xiaofei Wu; Jing Yang; Qihuang Gong

2008-01-01

306

Shape resonances in molecular fields  

SciTech Connect

A shape resonance is a quasibound state in which a particle is temporarily trapped by a potential barrier (i.e., the shape of the potential), through which it may eventually tunnel and escape. This simple mechanism plays a prominent role in a variety of excitation processes in molecules, ranging from vibrational excitation by slow electrons to ionization of deep core levels by x-rays. Moreover, their localized nature makes shape resonances a unifying link between otherwise dissimilar circumstances. One example is the close connection between shape resonances in electron-molecule scattering and in molecular photoionization. Another is the frequent persistence of free-molecule shape resonant behavior upon adsorption on a surface or condensation into a molecular solid. The main focus of this article is a discussion of the basic properties of shape resonances in molecular fields, illustrated by the more transparent examples studied over the last ten years. Other aspects to be discussed are vibrational effects of shape resonances, connections between shape resonances in different physical settings, and examples of shape resonant behavior in more complex cases, which form current challenges in this field.

Dehmer, J.L.

1984-01-01

307

Shape of the Kondo resonance  

Microsoft Academic Search

An electron scattering from a local impurity spin has its density of states altered by spin-flip scattering. This phenomenon causes a peak in the local density of states, which is called the ``Kondo resonance.'' We propose a simple formula for the shape of this resonance. For a dilute Kondo system, we use Fermi-liquid theory to calculate the effect of the

H. O. Frota

1992-01-01

308

[Myelin and nuclear magnetic resonance].  

PubMed

MRI is one of the most important tools for the investigation of white matter diseases of the central nervous system. Other techniques based on the magnetic resonance phenomena (magnetization transfer imaging, diffusion imaging, magnetic resonance spectroscopy) have joined MRI to better caracterize certain diseases, understand their pathophysiology and follow their evolution. PMID:18033031

Tourbah, A; Dormont, D; Galanaud, D; Sedel, F; Lyon-Caen, O

2007-10-01

309

All-optical clock recovery from 40 Gbit/s RZ signal based on microring resonators.  

PubMed

A scheme for high-speed clock recovery from return-to-zero (RZ) signal with microring resonators is presented. By using a silicon microring resonator (MRR) for clock extraction and a 3-order nonlinear series-coupled microring resonator (SCMR) for amplitude equalization, clock pulses with amplitude modulation less than 1 dB can be obtained. The proposed scheme is also designed and numerically studied by 3D full vectorial film mode matching method (FMM) and coupled mode theory (CMT). Simulation results show that clock can be recovered at 40 Gbit/s with short rise- and fall- times. PMID:22016205

Xiong, Meng; Ding, Yunhong; Zhang, Qiang; Zhang, Xinliang

2011-10-01

310

New Method for Determining the Quality Factor and Resonance Frequency of Superconducting Micro-resonators from Sonnet Simulation  

NASA Astrophysics Data System (ADS)

Lithographed superconducting microwave resonators (micro-resonators) are useful in a number of important applications including microwave kinetic inductance detectors (MKIDs), as a memory element in quantum information, and readout of qubits and nanomechanical resonators. One of the major tasks in designing these devices is to find the resonance frequency (fr) and quality factor (Q) for these microwave circuits using EM simulation software such as Sonnet. The traditional method iteratively sweeps and zooms in frequency to fit simulated S21 data, which is often time consuming. In this work, we show a new---and much faster---method for determining frand Q by adding an internal (virtual) port in the Sonnet model and examining the input impedance through the added port. Accurate fr and Q values can be retrieved from a single simulation with a wide frequency sweep. This is a robust method that works on many types of resonance circuits and eclipses the speed with which Q is traditionally extracted by eliminating the need for multiple frequency sweeps using Sonnet.

Wisbey, David; Reinisch, Alexander; Gardner, Wesley; Brewster, Jacob; Gao, Jiansong

2013-03-01

311

Delta connected resonant snubber circuit  

DOEpatents

A delta connected, resonant snubber-based, soft switching, inverter circuit achieves lossless switching during dc-to-ac power conversion and power conditioning with minimum component count and size. Current is supplied to the resonant snubber branches solely by the dc supply voltage through the main inverter switches and the auxiliary switches. Component count and size are reduced by use of a single semiconductor switch in the resonant snubber branches. Component count is also reduced by maximizing the use of stray capacitances of the main switches as parallel resonant capacitors. Resonance charging and discharging of the parallel capacitances allows lossless, zero voltage switching. In one embodiment, circuit component size and count are minimized while achieving lossless, zero voltage switching within a three-phase inverter. 36 figs.

Lai, J.S.; Peng, F.Z.; Young, R.W. Sr.; Ott, G.W. Jr.

1998-01-20

312

Delta connected resonant snubber circuit  

DOEpatents

A delta connected, resonant snubber-based, soft switching, inverter circuit achieves lossless switching during dc-to-ac power conversion and power conditioning with minimum component count and size. Current is supplied to the resonant snubber branches solely by the dc supply voltage through the main inverter switches and the auxiliary switches. Component count and size are reduced by use of a single semiconductor switch in the resonant snubber branches. Component count is also reduced by maximizing the use of stray capacitances of the main switches as parallel resonant capacitors. Resonance charging and discharging of the parallel capacitances allows lossless, zero voltage switching. In one embodiment, circuit component size and count are minimized while achieving lossless, zero voltage switching within a three-phase inverter.

Lai, Jih-Sheng (Knoxville, TN); Peng, Fang Zheng (Oak Ridge, TN); Young, Sr., Robert W. (Oak Ridge, TN); Ott, Jr., George W. (Knoxville, TN)

1998-01-01

313

Transverse-longitudinal integrated resonator  

DOEpatents

A transverse-longitudinal integrated optical resonator (TLIR) is disclosed which includes a waveguide, a first and a second subwavelength resonant grating in the waveguide, and at least one photonic band gap resonant structure (PBG) in the waveguide. The PBG is positioned between the first and second subwavelength resonant gratings. An electro-optic waveguide material may be used to permit tuning the TLIR and to permit the TLIR to perform signal modulation and switching. The TLIR may be positioned on a bulk substrate die with one or more electronic and optical devices and may be communicably connected to the same. A method for fabricating a TLIR including fabricating a broadband reflective grating is disclosed. A method for tuning the TLIR's transmission resonance wavelength is also disclosed.

Hutchinson, Donald P [Knoxville, TN; Simpson, Marcus L [Knoxville, TN; Simpson, John T [Knoxville, TN

2003-03-11

314

Extracting the Max From a DNA Extraction  

NSDL National Science Digital Library

Students of all ages get a thrill out of actually seeing clumps or strands of DNA. The Biotechnology/Bioinformatics Discovery! Project, a professional development workshop offered to science teachers, has always included a DNA-extraction activity. Over the course of four years, as the authors conducted these workshops for scores of teachers, they extended and refined the DNA-extraction activity to make it relevant to middle school students. Although the protocol for this exercise is on their project website along with teaching tips, they describe here the use of oral directions to give teachers many opportunities to interact with their students, and to assess how well students can follow directions and stay focused on the task.

Mulvihill, Charlotte; Bell, Don; Marek, Edmund

2009-01-01

315

Auxiliary resonant DC tank converter  

DOEpatents

An auxiliary resonant dc tank (ARDCT) converter is provided for achieving soft-switching in a power converter. An ARDCT circuit is coupled directly across a dc bus to the inverter to generate a resonant dc bus voltage, including upper and lower resonant capacitors connected in series as a resonant leg, first and second dc tank capacitors connected in series as a tank leg, and an auxiliary resonant circuit comprising a series combination of a resonant inductor and a pair of auxiliary switching devices. The ARDCT circuit further includes first clamping means for holding the resonant dc bus voltage to the dc tank voltage of the tank leg, and second clamping means for clamping the resonant dc bus voltage to zero during a resonant period. The ARDCT circuit resonantly brings the dc bus voltage to zero in order to provide a zero-voltage switching opportunity for the inverter, then quickly rebounds the dc bus voltage back to the dc tank voltage after the inverter changes state. The auxiliary switching devices are turned on and off under zero-current conditions. The ARDCT circuit only absorbs ripples of the inverter dc bus current, thus having less current stress. In addition, since the ARDCT circuit is coupled in parallel with the dc power supply and the inverter for merely assisting soft-switching of the inverter without participating in real dc power transmission and power conversion, malfunction and failure of the tank circuit will not affect the functional operation of the inverter; thus a highly reliable converter system is expected.

Peng, Fang Z. (Knoxville, TN)

2000-01-01

316

SOLVENT EXTRACTION PROCESS  

DOEpatents

In improved solvent extraction process is described for the extraction of metal values from highly dilute aqueous solutions. The process comprises contacting an aqueous solution with an organic substantially water-immiscible solvent, whereby metal values are taken up by a solvent extract phase; scrubbing the solvent extract phase with an aqueous scrubbing solution; separating an aqueous solution from the scrubbed solvent extract phase; and contacting the scrubbed solvent phase with an aqueous medium whereby the extracted metal values are removed from the solvent phase and taken up by said medium to form a strip solution containing said metal values, the aqueous scrubbing solution being a mixture of strip solution and an aqueous solution which contains mineral acids anions and is free of the metal values. The process is particularly effective for purifying uranium, where one starts with impure aqueous uranyl nitrate, extracts with tributyl phosphate dissolved in carbon tetrachloride, scrubs with aqueous nitric acid and employs water to strip the uranium from the scrubbed organic phase.

Jonke, A.A.

1957-10-01

317

Compact Hybrid Resonator With Series and Shunt Resonances Used in Miniaturized Filters and Balun Filters  

Microsoft Academic Search

A hybrid resonant circuit is proposed in this paper. The circuit is a combination of a shunt resonant circuit and series resonant circuit. With this combination, lower resonant frequency is achieved as compared to the single shunt and series resonant circuits. As a result, a compact resonator with smaller size can be achieved as compared to the conventional quarter- and

Tao Yang; Masaya Tamura; Tatsuo Itoh

2010-01-01

318

Narrow-Bandwidth Unstable Laser Resonator.  

National Technical Information Service (NTIS)

The present invention relates to unstable laser resonators and particularly to unstable laser resonators and particularly to an unstable laser resonator which produces optical radiation that simultaneously has the high output power diffraction-limited div...

J. F. Reintjes L. L. Tankersley D. Cooper

1988-01-01

319

Oscillatory extraction of uranium  

SciTech Connect

The kinetics of U and Ce extraction by tri-n-butyl-phosphate (TBP) and the redox potential behavior in the aqueous phase have been investigated in an oscillatory extraction system. The extraction has been followed continuously by UV-visible spectroscopy, potentiometry, and radioactive counting methods. Data collected showed the changes of Ce{sup 4+} and UO{sub 2}{sup 2+} concentrations in organic and aqueous phases with time. Uranium actively responded to the redox potential fluctuations. The uranium distribution coefficient changed repeatedly and was out-of-phase with Ce(IV) fluctuations.

Afonin, M.A.; Romanovski, V.V. [Saint Petersburg Inst. of Tech. (Russian Federation); Scherbakov, V.A. [Khlopin Radium Inst., Saint Petersburg (Russian Federation)

1998-08-01

320

Extraction of Seismic Waveforms.  

National Technical Information Service (NTIS)

This report considers the effects on detectability and measurability resulting from attempts to extract seismic waveforms by application of cascaded processors and polarization filters. Previous work has shown that bandpass or Wiener filters (when cascade...

A. C. Strauss

1978-01-01

321

Automatic Feature Extraction System.  

National Technical Information Service (NTIS)

The AFES (Automatic Feature Extraction System) is designed to be a testbed for evaluation of semi-automatic and computer-assisted techniques for automated production flow processes. Its intended input sources included National Sensors and LANDSAT imagery,...

J. L. Cambier

1982-01-01

322

Automated Metadata Extraction.  

National Technical Information Service (NTIS)

Metadata is data that describes data. There are many computer forensic uses of metadata and being able to extract metadata automatically provides positive forensic implications. This thesis presents a new technique for batch processing disk images and aut...

J. Migletz

2008-01-01

323

Secular resonance in extrasolar system  

NASA Astrophysics Data System (ADS)

The two orbits in the HD 160691 planetary system at first appeared highly unstable, but using a new technique called MEGNO (the acronym of Mean Exponential Growth factor of Nearby Orbits), we were able to identify a stability valley in the parameter space. This stability zone is due to the 2:1 mean motion resonance coupled with relative orbital positions of the planets avoiding close approaches in the closeness of their periastron, the two apsidal lines being anti-aligned. The mechanism itself is preserved by librations of the mean motion resonance variables while the longitudes of periapse on average precess at the same rate. The secular resonance variable of the HD 160691 system librates around 180o while it librates around 0o in the Gliese 876 system. We present an extended study of such mechanisms to the Io-Europa pair and the planetary system HD 82943 in order to compare in details these four original cases of secular resonances associated to the 2:1 resonance (Io-Europa, Gliese 876, HD 82943, HD 160691). We concluded that in order to be dynamically stable, the extrasolar planetary systems close to the 2:1 mean motion resonance have to satisfy an apsidal secular resonance and apparently high eccentricities. Because of high eccentricities of the orbits, and despite their relatively small semi-major axes, the relative distances between the two planets may indeed remain sufficiently large over the whole evolutionary time scale of the system.

Rambaux, N.; Bois, E.

2003-04-01

324

Liquid chromatographic extraction medium  

DOEpatents

A method and apparatus for extracting strontium and technetium values from biological, industrial and environmental sample solutions using a chromatographic column is described. An extractant medium for the column is prepared by generating a solution of a diluent containing a Crown ether and dispersing the solution on a resin substrate material. The sample solution is highly acidic and is introduced directed to the chromatographic column and strontium or technetium is eluted using deionized water.

Horwitz, E. Philip (Naperville, IL); Dietz, Mark L. (Evanston, IL)

1994-01-01

325

Fruitful DNA Extraction  

NSDL National Science Digital Library

In this lab activity, learners get to see and touch the genetic material they extract from the cells of a kiwi fruit - no high tech equipment required! After extraction and precipitation, learners will be able to collect the DNA with a wire hook. A facilitator's guide is included for helping educators run the activity, and background information is provided about what's going on, discussion questions, and ideas for inquiry. Biochemistry has never been so accessible - and fun!

Kalamuck, Karen; Exploratorium

2000-01-01

326

Optofluidic ring resonator dye lasers  

NASA Astrophysics Data System (ADS)

We overview the recent progress on optofluidic ring resonator (OFRR) dye lasers developed in our research group. The fluidics and laser cavity design can be divided into three categories: capillary optofluidic ring resonator (COFRR), integrated cylindrical optofluidic ring resonator (ICOFRR), and coupled optofluidic ring resonator (CpOFRR). The COFRR dye laser is based on a micro-sized glass capillary with a wall thickness of a few micrometers. The capillary circular cross-section forms the ring resonator and supports the whispering gallery modes (WGMs) that interact evanescently with the gain medium in the core. The laser cavity structure is versatile to adapt to the gain medium of any refractive index. Owing to the high Q-factor (>109), the lasing threshold of 25 nJ/mm2 is achieved. Besides directly pump the dye molecules, lasing through fluorescence resonance energy transfer (FRET) between the donor and acceptor dye molecules is also studied in COFRR laser. The energy transfer process can be further controlled by designed DNA scaffold labeled with donor/acceptor molecules. The ICOFRR dye laser is based on a cylindrical ring resonator fused onto the inner surface of a thick walled glass capillary. The structure has robust mechanical strength to sustain rapid gain medium circulation. The CpOFRR utilizes a cylindrical ring resonator fused on the inner surface of the COFRR capillary. Since the capillary wall is thin, the individual WGMs of the cylindrical ring resonator and the COFRR couples strongly and forms Vernier effect, which provides a way to generate a single mode dye laser.

Sun, Yuze; Suter, Jonathan D.; Fan, Xudong

2010-02-01

327

Evaluation of the Chromium Resonance Parameters Including Resonance Parameter Covariance  

SciTech Connect

The intent of this work is to report the results and describe the procedures utilized to evaluate the chromium isotopes' cross sections, i.e., (50)Cr, (52)Cr, (53)Cr, and (54)Cr, for criticality safety applications. The evaluations were done in the resolved resonance region using the reduced Reich-Moore R-matrix formalism. The novel aspect of this evaluation is the inclusion of new transmission and capture cross-section measurements performed at the Oak Ridge Electron Linear Accelerator (ORELA) for energies below 100 keV and the extension of the (53)Cr energy region. The resonance analysis was performed with the multilevel R-matrix code, SAMMY, which utilizes the generalized least-squares technique based on the Bayes' theory. Complete sets of resonance parameters and resonance parameter covariance matrices (RPCMs) were obtained for each of the chromium isotopes from the SAMMY analysis of the experimental database.

Leal, Luiz C [ORNL; Derrien, Herve [ORNL; Guber, Klaus H [ORNL; Arbanas, Goran [ORNL; Wiarda, Dorothea [ORNL

2011-01-01

328

High Q silica microbubble resonators  

NASA Astrophysics Data System (ADS)

Microbubble resonators (MBRs) combine the unique properties of whispering gallery mode resonators with the intrinsic capability of integrated microfluidics. Here an improved fabrication method of MBRs is presented, based on the heating of a slightly pressurized capillary by a rotating arc discharge. Rotation of the electrodes ensures an homogeneous distribution of the heat all over the capillary surface. The demonstrated MBRs have Q factors up to 107 at 773 nm. Microbubbles were filled with water and aqueous solutions of ethanol in order to test the refractive index sensing capabilities of such resonators, which also show a good temporal stability.

Farnesi, D.; Barucci, A.; Berneschi, S.; Brenci, M.; Cosi, F.; Nunzi Conti, G.; Pelli, S.; Righini, G. C.; Soria, S.

2012-02-01

329

Resonance mode in DNA dynamics  

NASA Astrophysics Data System (ADS)

In this article we use Peyrard-Bishop-Dauxois model (PBD) to study the nonlinear oscillations of DNA nucleotides of extremely high amplitude (EHA) leading to unzipping of DNA chain in the context of the process of replication. We give arguments that the EHA mode is nothing but the resonance mode (RM). We launched an idea about how molecular mechano-chemical energy transduction can be the origin of the RM. We compared some parameters of the solitonic wave in DNA in resonant and non-resonant regime.

Zdravkovic, S.; Sataric, M. V.

2007-11-01

330

Nuclear magnetic resonance contrast agents  

DOEpatents

A family of contrast agents for use in magnetic resonance imaging and a method of enhancing the contrast of magnetic resonance images of an object by incorporating a contrast agent of this invention into the object prior to forming the images or during formation of the images. A contrast agent of this invention is a paramagnetic lanthanide hexaazamacrocyclic molecule, where a basic example has the formula LnC{sub 16}H{sub 14}N{sub 6}. Important applications of the invention are in medical diagnosis, treatment, and research, where images of portions of a human body are formed by means of magnetic resonance techniques. 10 figs.

Smith, P.H.; Brainard, J.R.; Jarvinen, G.D.; Ryan, R.R.

1997-12-30

331

Nuclear magnetic resonance contrast agents  

DOEpatents

A family of contrast agents for use in magnetic resonance imaging and a method of enhancing the contrast of magnetic resonance images of an object by incorporating a contrast agent of this invention into the object prior to forming the images or during formation of the images. A contrast agent of this invention is a paramagnetic lanthanide hexaazamacrocyclic molecule, where a basic example has the formula LnC.sub.16 H.sub.14 N.sub.6. Important applications of the invention are in medical diagnosis, treatment, and research, where images of portions of a human body are formed by means of magnetic resonance techniques.

Smith, Paul H. (Los Alamos, NM); Brainard, James R. (Los Alamos, NM); Jarvinen, Gordon D. (Los Alamos, NM); Ryan, Robert R. (Los Alamos, NM)

1997-01-01

332

Multiple resonant railgun power supply  

DOEpatents

A multiple repetitive resonant railgun power supply provides energy for repetitively propelling projectiles from a pair of parallel rails. A plurality of serially connected paired parallel rails are powered by similar power supplies. Each supply comprises an energy storage capacitor, a storage inductor to form a resonant circuit with the energy storage capacitor and a magnetic switch to transfer energy between the resonant circuit and the pair of parallel rails for the propelling of projectiles. The multiple serial operation permits relatively small energy components to deliver overall relatively large amounts of energy to the projectiles being propelled.

Honig, Emanuel M. (Los Alamos, NM); Nunnally, William C. (Los Alamos, NM)

1988-01-01

333

Resonant Excitation of Plasma Wakefields  

SciTech Connect

We describe characteristics of the bunch train and plasma source used in a resonant plasma wakefield experiment at the Brookhaven National Laboratory Accelerator Test Facility. The bunch train has the proper correlated spread to unambiguously observe the expected energy gain by the witness bunch at resonance. The plasma density in the capillary discharge is sufficiently high to reach the resonance with the typical bunch train spacing of this experiment. It is also uniform over more than 3/4 of the 2 cm-long capillary.

Muggli, P.; Allen, B. [University of Southern California, Los Angeles, CA 90089 (United States); Yakimenko, V.; Fedurin, M.; Kusche, K.; Babzien, M. [Brookhaven National Laboratory, Upton, NY 11973 (United States)

2010-11-04

334

Transverse electron resonance accelerator  

SciTech Connect

Transverse (to the velocity, v, of the particles to be accelerated) electron oscillations are generated in high (e.g. solid) density plasmas by either an electromagnetic wave or by the field of charged particles traveling parallel to v. The generating field oscillates with frequency ..omega.. = ..omega../sub p/, where ..omega../sub p/ is the plasma frequency. The plasma is confined to a sequence of microstructures with typical dimensions of d approx. = 2..pi..c/..omega../sub p/, allowing the generating fields to penetrate. Since ..omega../sub p/ is now high, the time scales, T, are correspondingly reduced. The microstructures are allowed to explode after t = T, until then they are confined by ion inertia. As a result of resonance, the electric field, E, inside the microstructures can exceed the generating field E/sub L/. The generating force is proportional to E/sub L/ (as opposed to E/sub L//sup 2/). Phase matching of particles is possible by appropriate spacing of the microstructures or by a gas medium. The generating beam travels outside the plasma, filamentation is not a problem. The mechanism is relatively insensitive to the exact shape and position of the microstructures. This device contains features of various earlier proposed acceleration mechanisms and may be considered as the limiting case of several of those for small d, T and high E.

Csonka, P.L.

1985-01-01

335

Nuclear magnetic resonance spectrometry  

SciTech Connect

This review covers the published literature from July 1983 to August 1985 although some citations of other work are also included. As noted in earlier reviews it is impossible to summarize 2 years of NMR literature in so short a space. However, it is hoped that the books, reviews, and various citations will be a useful guide to the reader. The publication Spectroscopy (PO Box 50, Springfield, OR 97477; H. W. Lafferty, Ed.) has recently commenced and promises to be of interest and utility in various areas of spectroscopy, including NMR. Noninvasive Medical Imaging, an international journal published by Verlag Chemie GmbH (Federal Republic of Germany) and Reviews of Magnetic Resonance in Medicine published by Pergamon Press cover specialized application of NMR. The American Chemical Society has introduced an audiocassette course on Fourier Transform NMR Spectroscopy. An extensive C13 NMR Data Base has been made available by Science Information Services, Inc., Larchmont, NY, and City Software, Milwaukee, WI has introduced The NMR Simulator for the IBM PC. 342 references, 2 tables.

Wasson, J.R.

1986-04-01

336

Magnetic resonance cell  

SciTech Connect

There is disclosed a nuclear magnetic alignment device for use in a nuclear magnetic resonance gyroscope and the like. One embodiment includes a container for gas having a layer of rubidium hydride on its inner surface. The container comprising a spherical portion and a tip portion, is rotationally symmetric about an axis of symmetry. Enclosed within the container is a nuclear moment gas having a nuclear electric quadrupole moment, such as xenon-131, and an optically pumpable substance, such as rubidium. A portion of the rubidium is a vapor. The remainder is a condensed pellet which is deposited in the tip of the container such that the pellet is also rotationally symmetric about the axis of symmetry of the container. A layer of rubidium hydride is deposited on the inner surface of the container. The device further includes means for orienting the symmetry axis of the container at an angle to an applied magnetic field such that the relaxation time constant of the aligned nuclear moment gas is substantially at a maximum.

Kwon, T.M.; Volk, C.H.

1984-05-01

337

Nuclear Magnetic Resonance (NMR) Guidelines.  

National Technical Information Service (NTIS)

Nuclear Magnetic Resonance (NMR) is a medical diagnostic imaging technique that applies the atomic principles of magnetic spin to visualize and analyze disease states in bodily tissues. NMR differs from the radiological devices in that (a) it does not uti...

R. Halpern

1983-01-01

338

Morphological resonances for multicomponent immunoassays  

NASA Astrophysics Data System (ADS)

An immunoassay technique capable of detecting and identifying a number of species of microorganisms in a single analysis is described. The method uses optical-resonance size discrimination of microspheres to identify antibodies to which stained microorganisms are bound.

Whitten, W. B.; Shapiro, M. J.; Ramsey, J. M.; Bronk, B. V.

1995-06-01

339

Chemically Polished High Frequency Resonators.  

National Technical Information Service (NTIS)

The upper frequency limit of quartz resonators is determined by the physical properties of quartz and restrictions imposed by processing techniques. More often than not, the processing limitations are reached long before the physical limitations. Mechanic...

W. P. Hanson

1983-01-01

340

Resonant states in momentum representation  

SciTech Connect

Gamow states in momentum representation are defined as solutions of a homogeneous Lippmann-Schwinger equation for purely outgoing particles. We study their properties when the potential, local or nonlocal, is such that the trace of the kernel of the Lippmann-Schwinger equation exists. It is found that, contrary to what happens in position representation, Gamow states in momentum representation are square integrable functions. A norm is defined and expressions for matrix elements of operators between arbitrary states and properly normalized resonant states are given, free of divergence difficulties. It is also shown that bound and resonant states form a biorthonormal set of functions with their adjoints and that a square integrable function may be expanded in terms of a set containing bound states, resonant states, and a continuum of scattering functions. Resonant states may be transformed from momentum to position representation modifying, in a suitable way, the usual rule.

Hernandez, E.; Mondragon, A.

1984-03-01

341

Orthopaedic Magnetic Resonance Imaging Challenge  

PubMed Central

Apophyseal avulsion injuries of the hip and pelvis are frequent athletic injuries in children and adolescents, most commonly associated with explosive movement or sprinting. This article details typically encountered apophyseal injuries and their appearance on magnetic resonance imaging.

Kjellin, Ingrid; Stadnick, Michael E.; Awh, Mark H.

2010-01-01

342

Fluorine-19 Nuclear Magnetic Resonance.  

National Technical Information Service (NTIS)

Several series of diadducts of titanium tetrafluoride were studied with high resolution fluorine-19 nuclear magnetic resonance spectroscopy. These consisted of studies with aromatic amine oxides, amides and sulfoxides as bases. Mixed diadducts of TiF4 wit...

R. O. Ragsdale

1971-01-01

343

Resonate-and-fire neurons.  

PubMed

We suggest a simple spiking model-resonate-and-fire neuron, which is similar to the integrate-and-fire neuron except that the state variable is complex. The model provides geometric illustrations to many interesting phenomena occurring in biological neurons having subthreshold damped oscillations of membrane potential. For example, such neurons prefer a certain resonant frequency of the input that is nearly equal to their eigenfrequency, they can be excited or inhibited by a doublet (two pulses) depending on its interspike interval, and they can fire in response to an inhibitory input. All these properties could be observed in Hodgkin-Huxley-type models. We use the resonate-and-fire model to illustrate possible sensitivity of biological neurons to the fine temporal structure of the input spike train. Being an analogue of the integrate-and-fire model, the resonate-and-fire model is computationally efficient and suitable for simulations of large networks of spiking neurons. PMID:11665779

Izhikevich, E M

344

A micro-machined resonator  

DOEpatents

This invention is comprised of a micro-machined resonator, typically quartz, with upper and lower micromachinable support members, or covers, having etched wells which may be lined with conductive electrode material, between the support members is a quartz resonator having an energy trapping quartz mesa capacitively coupled to the electrodes through a diaphragm; the quartz resonator is supported by either micro-machined cantilever springs or by thin layers extending over the surfaces of the support. If the diaphragm is rigid, clock applications are available, and if the diaphragm is resilient, then transducer applications can be achieved. Either the thin support layers or the conductive electrode material can be integral with the diaphragm. In any event, the covers are bonded to form a hermetic seal and the interior volume may be filled with a gas or may be evacuated. In addition, one or both of the covers may include oscillator and interface circuitry for the resonator.

Godshall, N.A.; Koehler, D.R.; Liang, A.Y.; Smith, B.K.

1991-12-31

345

Beam current enhancement of microwave plasma ion source utilizing double-port rectangular cavity resonator  

SciTech Connect

Microwave plasma ion source with rectangular cavity resonator has been examined to improve ion beam current by changing wave launcher type from single-port to double-port. The cavity resonators with double-port and single-port wave launchers are designed to get resonance effect at TE-103 mode and TE-102 mode, respectively. In order to confirm that the cavities are acting as resonator, the microwave power for breakdown is measured and compared with the E-field strength estimated from the HFSS (High Frequency Structure Simulator) simulation. Langmuir probe measurements show that double-port cavity enhances central density of plasma ion source by modifying non-uniform plasma density profile of the single-port cavity. Correspondingly, beam current from the plasma ion source utilizing the double-port resonator is measured to be higher than that utilizing single-port resonator. Moreover, the enhancement in plasma density and ion beam current utilizing the double-port resonator is more pronounced as higher microwave power applied to the plasma ion source. Therefore, the rectangular cavity resonator utilizing the double-port is expected to enhance the performance of plasma ion source in terms of ion beam extraction.

Lee, Yuna; Park, Yeong-Shin; Jo, Jong-Gab; Yang, J. J.; Hwang, Y. S. [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)

2012-02-15

346

Beam current enhancement of microwave plasma ion source utilizing double-port rectangular cavity resonator.  

PubMed

Microwave plasma ion source with rectangular cavity resonator has been examined to improve ion beam current by changing wave launcher type from single-port to double-port. The cavity resonators with double-port and single-port wave launchers are designed to get resonance effect at TE-103 mode and TE-102 mode, respectively. In order to confirm that the cavities are acting as resonator, the microwave power for breakdown is measured and compared with the E-field strength estimated from the HFSS (High Frequency Structure Simulator) simulation. Langmuir probe measurements show that double-port cavity enhances central density of plasma ion source by modifying non-uniform plasma density profile of the single-port cavity. Correspondingly, beam current from the plasma ion source utilizing the double-port resonator is measured to be higher than that utilizing single-port resonator. Moreover, the enhancement in plasma density and ion beam current utilizing the double-port resonator is more pronounced as higher microwave power applied to the plasma ion source. Therefore, the rectangular cavity resonator utilizing the double-port is expected to enhance the performance of plasma ion source in terms of ion beam extraction. PMID:22380295

Lee, Yuna; Park, Yeong-Shin; Jo, Jong-Gab; Yang, J J; Hwang, Y S

2012-02-01

347

Sensitive Disk Resonator Photonic Biosensor  

Microsoft Academic Search

We describe a photonic device based on a high-finesse, whispering-gallery-mode disk resonator that can be used for the detection of biological pathogens. This device operates by means of monitoring the change in transfer characteristics of the disk resonator when biological materials fall onto its active area. High sensitivity is achieved because the light wave interacts many times with each pathogen

Robert W. Boyd; John E. Heebner

2001-01-01

348

Matryoshka Locally Resonant Sonic Crystal  

Microsoft Academic Search

The results of numerical modelling of sonic crystals with resonant array\\u000aelements are reported. The investigated resonant elements include plain slotted\\u000acylinders as well as various their combinations, in particular, Russian doll or\\u000aMatryoshka configurations. The acoustic band structure and transmission\\u000acharacteristics of such systems have been computed with the use of finite\\u000aelement methods. The general concept of a

Daniel P. Elford; Luke Chalmers; Feodor V. Kusmartsev; Gerry M. Swallowe

2011-01-01

349

Empathy in schizophrenia: impaired resonance  

Microsoft Academic Search

Resonance is the phenomenon of one person unconsciously mirroring the motor actions as basis of emotional expressions of another\\u000a person. This shared representation serves as a basis for sharing physiological and emotional states of others and is an important\\u000a component of empathy. Contagious laughing and contagious yawning are examples of resonance. In the interpersonal contact with\\u000a individuals with schizophrenia we

Helene Haker; Wulf Rössler

2009-01-01

350

Particle diffusion in overlapping resonances  

SciTech Connect

Longitudinal bunch dilution was studied in the IUCF Cooler Ring with phase modulation of a higher-order harmonic rf. Diffusion in the presence of overlapping parametric resonances has been identified as the dilution mechanism. We found that fast growth is associated with the rapid particle motion along separatrices of dominant parametric resonances, slow growth is related to particle diffusion in the chaotic sea, and saturation occurs when particles are bounded by an invariant torus.

Ng, K.Y.

1998-01-01

351

Resonance behaviors and mirror neurons.  

PubMed

This article is subdivided into two parts. In the first part we review the properties of a particular class of premotor neurons, the "mirror" neurons. With this term we define neurons that discharge both when the monkey makes a particular action and when it observes another individual (monkey or human) making a similar action. The second part is an attempt to give a neurophysiological account of the mechanisms underlying behaviors where an individual reproduces, overtly or internally, movements or actions made by another individual. We will refer to these behaviors as "resonance behaviors". We distinguish two types of resonance behavior. The first type is characterized by imitation, immediate or with delay, of movements made by other individuals. Examples of resonance behavior of this type are the "imitative" behaviors observed in birds, young infants and patients with frontal lesions. The second type of resonance behavior is characterized by the occurrence, at the observation of an action, of a neural pattern, which, when internally generated, determines the making of the observed action. In this type of resonance behavior the observed action is, typically, not repeated (overtly). We argue that resonance behavior of the second type is at the basis of the understanding of actions made by others. At the end of the article we review evidence of mirror mechanisms in humans and discuss their anatomical localizations. PMID:10349488

Rizzolatti, G; Fadiga, L; Fogassi, L; Gallese, V

1999-05-01

352

Empathy in schizophrenia: impaired resonance.  

PubMed

Resonance is the phenomenon of one person unconsciously mirroring the motor actions as basis of emotional expressions of another person. This shared representation serves as a basis for sharing physiological and emotional states of others and is an important component of empathy. Contagious laughing and contagious yawning are examples of resonance. In the interpersonal contact with individuals with schizophrenia we can often experience impaired empathic resonance. The aim of this study is to determine differences in empathic resonance-in terms of contagion by yawning and laughing-in individuals with schizophrenia and healthy controls in the context of psychopathology and social functioning. We presented video sequences of yawning, laughing or neutral faces to 43 schizophrenia outpatients and 45 sex- and age-matched healthy controls. Participants were video-taped during the stimulation and rated regarding contagion by yawning and laughing. In addition, we assessed self-rated empathic abilities (Interpersonal Reactivity Index), psychopathology (Positive and Negative Syndrome Scale in the schizophrenia group resp. Schizotypal Personality Questionnaire in the control group), social dysfunction (Social Dysfunction Index) and executive functions (Stroop, Fluency). Individuals with schizophrenia showed lower contagion rates for yawning and laughing. Self-rated empathic concern showed no group difference and did not correlate with contagion. Low rate of contagion by laughing correlated with the schizophrenia negative syndrome and with social dysfunction. We conclude that impaired resonance is a handicap for individuals with schizophrenia in social life. Blunted observable resonance does not necessarily reflect reduced subjective empathic concern. PMID:19377866

Haker, Helene; Rössler, Wulf

2009-04-18

353

Micro-machined resonator oscillator  

DOEpatents

A micro-miniature resonator-oscillator is disclosed. Due to the miniaturization of the resonator-oscillator, oscillation frequencies of one MHz and higher are utilized. A thickness-mode quartz resonator housed in a micro-machined silicon package and operated as a "telemetered sensor beacon" that is, a digital, self-powered, remote, parameter measuring-transmitter in the FM-band. The resonator design uses trapped energy principles and temperature dependence methodology through crystal orientation control, with operation in the 20-100 MHz range. High volume batch-processing manufacturing is utilized, with package and resonator assembly at the wafer level. Unique design features include squeeze-film damping for robust vibration and shock performance, capacitive coupling through micro-machined diaphragms allowing resonator excitation at the package exterior, circuit integration and extremely small (0.1 in. square) dimensioning. A family of micro-miniature sensor beacons is also disclosed with widespread applications as bio-medical sensors, vehicle status monitors and high-volume animal identification and health sensors. The sensor family allows measurement of temperatures, chemicals, acceleration and pressure. A microphone and clock realization is also available.

Koehler, Dale R. (Albuquerque, NM); Sniegowski, Jeffry J. (Albuquerque, NM); Bivens, Hugh M. (Albuquerque, NM); Wessendorf, Kurt O. (Albuquerque, NM)

1994-01-01

354

Micro-machined resonator oscillator  

DOEpatents

A micro-miniature resonator-oscillator is disclosed. Due to the miniaturization of the resonator-oscillator, oscillation frequencies of one MHz and higher are utilized. A thickness-mode quartz resonator housed in a micro-machined silicon package and operated as a telemetered sensor beacon'' that is, a digital, self-powered, remote, parameter measuring-transmitter in the FM-band. The resonator design uses trapped energy principles and temperature dependence methodology through crystal orientation control, with operation in the 20--100 MHz range. High volume batch-processing manufacturing is utilized, with package and resonator assembly at the wafer level. Unique design features include squeeze-film damping for robust vibration and shock performance, capacitive coupling through micro-machined diaphragms allowing resonator excitation at the package exterior, circuit integration and extremely small (0.1 in. square) dimensioning. A family of micro-miniature sensor beacons is also disclosed with widespread applications as bio-medical sensors, vehicle status monitors and high-volume animal identification and health sensors. The sensor family allows measurement of temperatures, chemicals, acceleration and pressure. A microphone and clock realization is also available. 21 figs.

Koehler, D.R.; Sniegowski, J.J.; Bivens, H.M.; Wessendorf, K.O.

1994-08-16

355

Tevatron extraction microcomputer  

SciTech Connect

Extraction in the Fermilab Tevatron is controlled by a multi-processor Multibus microcomputer system called QXR (Quad eXtraction Regulator). QXR monitors several analog beam signals and controls three sets of power supplies: the ''bucker'' and ''pulse'' magnets at a rate of 5760 Hz, and the ''QXR'' magnets at 720 Hz. QXR supports multiple slow spills (up to a total of 35 seconds) with multiple fast pulses intermixed. It linearizes the slow spill and bucks out the high frequency components. Fast extraction is done by outputting a variable pulse waveform. Closed loop learning techniques are used to improve performance from cycle to cycle for both slow and fast extraction. The system is connected to the Tevatron clock system so that it can track the machine cycle. QXR is also connected to the rest of the Fermilab control system, ACNET. Through ACNET, human operators and central computers can monitor and control extraction through communications with QXR. The controls hardware and software both employ some standard and some specialized components. This paper gives an overview of QXR as a control system; another paper summarizes performance.

Chapman, L.; Finley, D.A.; Harrison, M.; Merz, W.

1985-06-01

356

Tevatron extraction microcomputer  

NASA Astrophysics Data System (ADS)

Extraction in the fErmilab Tevatron is controlled by a multi-processor Multibus microcomputer system called QXR (Quad extraction Regulator). QXR monitors several analog beam signals and controls three sets of power supplies: the bucker and pulse magnets at a rate of 5760 Hz, and the QXR magnets at 720 Hz. QXR supports multiple slow spills (up to a total of 35 seconds) with multiple fast pulses intermixed. It linearizes the slow spill and bucks out the high frequency components. Fast extraction is done by outputting a variable pulse waveform. Closed loop learning techniques are used to improve performance from cycle to cycle for both slow and fast extraction. The system is connected to the Tevatron clock system so that it can track the machine cycle. QXR is also connected to the rest of the Fermilab control system, ACNET. Through ACNET, human operators and central computers can monitor and control extraction through communications with QXR. The controls hardware and software both employ some standard and some specialized components. This paper gives an overview of QXR as a control system; another paper summarizes performance.

Chapman, L.; Finley, D. A.; Harrison, M.; Merz, W.

1985-06-01

357

Nanoparticle sensing using whispering-gallery-mode resonators: Plasmonic and Rayleigh scatterers  

NASA Astrophysics Data System (ADS)

The theory of nanoparticle sensing using whispering-gallery-mode resonators is investigated for both plasmonic and Rayleigh scatterers. In particular, we describe how to extract critical information, such as the number of particles adsorbed, from the transmission spectrum. The effects of the interference due to multiple interparticle scatterings are elucidated. Analytical expressions are derived so as to enable further numerical analysis.

Shen, Yuecheng; Shen, Jung-Tsung

2012-01-01

358

Left ventricular segmentation of cardiac magnetic resonance images using a novel edge following technique  

Microsoft Academic Search

This paper presents a novel edge following technique for image segmentation designed to segment the left ventricle in cardiac magnetic resonance (MR) images. This is a required step to determine the volume of left ventricle in a cardiac MR image, which is an essential tool for cardiac diagnosis. The traditional method for extracting them from cardiac MR images is by

Krit Somkantha; Nipon Theera-Umpon; Sansanee Auephanwiriyakul

2008-01-01

359

Automatic Segmentation and Quantitative Analysis of the Articular Cartilages From Magnetic Resonance Images of the Knee  

Microsoft Academic Search

In this paper, we present a segmentation scheme that automatically and accurately segments all the cartilages from magnetic resonance (MR) images of nonpathological knees. Our scheme involves the automatic segmentation of the bones using a three-dimensional active shape model, the extraction of the expected bone-cartilage interface (BCI), and cartilage segmentation from the BCI using a deformable model that utilizes localization,

Jurgen Fripp; Stuart Crozier; Simon K. Warfield; Sébastien Ourselin

2010-01-01

360

Magnetic resonance image analysis by information theoretic criteria and stochastic site models  

Microsoft Academic Search

Abstract, Quantitative analysis of magnetic resonance (MR) images is a powerful tool for image-guided diagnosis, monitoring, and intervention. The major tasks involve tissue quantification and image segmentation where both the pixel and context images are considered. To extract clinically useful information from images that might be lacking in prior knowledge, we introduce an unsu-pervised tissue characterization algorithm that is both

Yue Wang; Tülay Adali; Jianhua Xuan; Zsolt Szabo

2001-01-01

361

Evolution of the pygmy dipole resonance in Sn isotopes  

NASA Astrophysics Data System (ADS)

Nuclear level density and ?-ray strength functions of Sn121,122 below the neutron separation energy are extracted with the Oslo method using the (He3,He3'?) and (He3,??) reactions. The level densities of Sn121,122 display steplike structures, interpreted as signatures of neutron pair breaking. An enhancement in both strength functions, compared to standard models for radiative strength, is observed in our measurements for E??5.2 MeV. This enhancement is compatible with pygmy resonances centered at ?8.4(1) and ?8.6(2) MeV, respectively, and with integrated strengths corresponding to ?1.8-5+1% of the classical Thomas-Reiche-Kuhn sum rule. Similar resonances were also seen in Sn116-119. Experimental neutron-capture cross reactions are well reproduced by our pygmy resonance predictions, while standard strength models are less successful. The evolution as a function of neutron number of the pygmy resonance in Sn116-122 is described as a clear increase of centroid energy from 8.0(1) to 8.6(2) MeV, but with no observable difference in integrated strengths.

Toft, H. K.; Larsen, A. C.; Bürger, A.; Guttormsen, M.; Görgen, A.; Nyhus, H. T.; Renstrøm, T.; Siem, S.; Tveten, G. M.; Voinov, A.

2011-04-01

362

Metabolic brain imaging by magnetic resonance  

Microsoft Academic Search

Novel magnetic resonance methods have been developed to noninvasively measure biochemical compounds in the human brain as guided by magnetic resonance imaging. Together, these methods are referred to as magnetic resonance spectroscopy (MRS) and can be divided into three major categories: single voxel MRS, magnetic resonance spectroscopic imaging and dynamic MRS, which is a novel adaption of the first method.

Edward J Novotny Jr

2006-01-01

363

Field Concentrator Based Resonant Magnetic Sensor  

Microsoft Academic Search

A novel resonant magnetic sensor based on the combination of a mechanical resonator and a magnetic field concentrator with two gaps is reported. In contrast to previous Lorentz force based resonant magnetic sensors, a high sensitivity is achieved without modulated driving current and complex feedback electronics. Furthermore, compared to magnetic moment based resonant magnetic sensors, the new concept requires no

S. Brugger; P. Simon; O. Paul

2006-01-01

364

Theory of Atomic Motion in Resonant Radiation  

Microsoft Academic Search

Atomic motion in resonant and near resonant electromagnetic radiation is investigated theoretically. The exposition begins with a study of atomic motion in a resonant standing light wave, with a view toward isotope separation by selective photodeflection, and proceeds to the investigation of more general problems of atomic motion in resonant radiation. The body of the work consists of six chapters,

Richard Joseph Cook

1979-01-01

365

Temperature Dependence of Resonances in Metamaterials  

Microsoft Academic Search

Metamaterials are increasingly being proposed for many different microwave applications. Metamaterials are highly resonant structures and metamaterial device design is based on the resonance frequency for both civilian and military applications. These applications are often in a high-temperature environment. In this paper, we have performed an experimental study of the shift in resonance frequency of selected metamaterials (split-ring resonators and

Vasundara V. Varadan; Liming Ji

2010-01-01

366

Collective Resonances in Pion-Nucleus Scattering  

Microsoft Academic Search

Pion-nucleus scattering is described by the excitation of bound nucleons into the Delta resonance leading to isobaric resonances of the whole nucleus. A few broad collective resonances of different multipolarity are shown to dominate elastic and inelastic pi-12C scattering. From the qualitatively good agreement with the data, we conclude that those giant isobaric resonances are a general feature of the

K. Klingenbeck; M. Dillig; M. G. Huber

1978-01-01

367

Numerical analysis of plasmon resonances in nanoparticles  

Microsoft Academic Search

Plasmon (electrostatic) resonances in nanoparticles are treated as an eigenvalue problem for a specific boundary integral equation. This leads to direct calculation of resonance values of permittivity and resonance frequency. The numerical technique is illustrated by examples of calculation of resonance frequencies for three-dimensional nanoparticles

Isaak D. Mayergoyz; Zhenyu Zhang

2006-01-01

368

Microelectromechanical resonator and method for fabrication  

DOEpatents

A method is disclosed for the robust fabrication of a microelectromechanical (MEM) resonator. In this method, a pattern of holes is formed in the resonator mass with the position, size and number of holes in the pattern being optimized to minimize an uncertainty .DELTA.f in the resonant frequency f.sub.0 of the MEM resonator due to manufacturing process variations (e.g. edge bias). A number of different types of MEM resonators are disclosed which can be formed using this method, including capacitively transduced Lame, wineglass and extensional resonators, and piezoelectric length-extensional resonators.

Wittwer, Jonathan W. (Albuquerque, NM); Olsson, Roy H. (Albuquerque, NM)

2010-01-26

369

Microelectromechanical resonator and method for fabrication  

DOEpatents

A method is disclosed for the robust fabrication of a microelectromechanical (MEM) resonator. In this method, a pattern of holes is formed in the resonator mass with the position, size and number of holes in the pattern being optimized to minimize an uncertainty .DELTA.f in the resonant frequency f.sub.0 of the MEM resonator due to manufacturing process variations (e.g. edge bias). A number of different types of MEM resonators are disclosed which can be formed using this method, including capacitively transduced Lame, wineglass and extensional resonators, and piezoelectric length-extensional resonators.

Wittwer, Jonathan W. (Albuquerque, NM); Olsson, Roy H. (Albuquerque, NM)

2009-11-10

370

Precision and accuracy in diffusion tensor magnetic resonance imaging.  

PubMed

This article reviews some of the key factors influencing the accuracy and precision of quantitative metrics derived from diffusion magnetic resonance imaging data. It focuses on the study pipeline beginning at the choice of imaging protocol, through preprocessing and model fitting up to the point of extracting quantitative estimates for subsequent analysis. The aim was to provide the newcomers to the field with sufficient knowledge of how their decisions at each stage along this process might impact on precision and accuracy, to design their study/approach, and to use diffusion tensor magnetic resonance imaging in the clinic. More specifically, emphasis is placed on improving accuracy and precision. I illustrate how careful choices along the way can substantially affect the sample size needed to make an inference from the data. PMID:21613874

Jones, Derek K

2010-04-01

371

Nonlinear acoustic resonances to probe a threaded interface  

NASA Astrophysics Data System (ADS)

We evaluate the sensitivity of multimodal nonlinear resonance spectroscopy to torque changes in a threaded interface. Our system is comprised of a bolt progressively tightened in an aluminum plate. Different modes of the system are studied in the range 1-25 kHz, which correspond primarily to bending modes of the plate. Nonlinear parameters expressing the importance of resonance frequency and damping variations are extracted and compared to linear ones. The influence of each mode shape on the sensitivity of nonlinear parameters is discussed. Results suggest that a multimodal measurement is an appropriate and sensitive method for monitoring bolt tightening. Further, we show that the nonlinear components provide new information regarding the interface, which can be linked to different friction theories. This work has import to study of friction and to nondestructive evaluation of interfaces for widespread application and basic research.

Rivière, Jacques; Renaud, Guillaume; Haupert, Sylvain; Talmant, Maryline; Laugier, Pascal; Johnson, Paul A.

2010-06-01

372

EXTRACTION OF URANIUM  

DOEpatents

A method is given for extracting metal values from an aqueous feed wherein the aqueous feed is passed countercurrent to an organic extractant through a plurality of decanting zones and a portion of the mixture contained in each decanting zone is recycled through a mixing zone associated therewith. The improvement consists of passing more solvent from the top of one decanting zone to the bottom of the preceding decanting zone than can rise to the top thereof and recycling that portion of the solvent that does not rise to the top back to the first named decanting zone through its associated mixing zone.

Schmieding, E.G.; Ruehle, A.E.

1961-04-11

373

Phytoplasma plasmid DNA extraction.  

PubMed

Phytoplasma plasmids have generally been detected from DNA extracted from plants and insects using methods designed for the purification of total phytoplasma DNA. Methods include extraction from tissues that are high in phytoplasma titre, such as the phloem of plants, with the use of CsCl-bisbenzimide gradients that exploit the low G+C content of phytoplasma DNA. Many of the methods employed for phytoplasma purification have been described elsewhere in this book. Here we describe in detail two methods that are specifically aimed at isolating plasmid DNA. PMID:22987431

Andersen, Mark T; Liefting, Lia W

2013-01-01

374

Resonant and non-resonant microwave absorption as a probe of the magnetic dynamics and switching in spin valves  

NASA Astrophysics Data System (ADS)

We use the resonant and non-resonant microwave absorption to probe the dynamic and static magnetic parameters of weakly coupled spin valves. The sample series include spin valve structures with varying thickness of the non-magnetic metallic spacer and reference samples comprised only a free or fixed magnetic layer. Beside the common resonance absorption peaks, the observed microwave spectra present step-like features with hysteretic behavior. The latter effect is a direct manifestation of the interlayer coupling between the ferromagnetic layers and provides two static magnetic parameters, the switching field and coercivity of the fixed layer. The analysis of the microwave absorption spectra under in-plane rotation of the applied magnetic field at different spacer thicknesses permits a deeper insight in the magnetic interactions in this system as compared to the conventional magnetometry. We combine the standard Smit-Beljers formalism for the angular dependence of the resonance fields with a Landau-Lifshitz-Gilbert dynamics extended to describe in detail the intensity of microwave absorption in the spin valves. In this way, we extract a set of parameters for each layer including the effective magnetization and anisotropy, exchange bias and interlayer coupling, as well as Gilbert damping. The model reproduces well the experimental findings, both qualitatively and quantitatively, and the estimated parameters are in a reasonable agreement with the values known from the literature. The proposed theoretical treatment can be adopted for other multilayered dynamic systems as, e.g., spin-torque oscillators.

Timopheev, A. A.; Sobolev, N. A.; Pogorelov, Y. G.; Talalaevskij, A. V.; Teixeira, J. M.; Cardoso, S.; Freitas, P. P.; Kakazei, G. N.

2013-07-01

375

Resonant power supplies - Their history and status  

NASA Astrophysics Data System (ADS)

A development history and current status evaluation are furnished for resonant power supplies, in which an input dc voltage is applied through controlled switches to an inductance-capacitance resonant circuit. Attention is given to single- and double-switch resonant converters, series and parallel resonant converters, and the advantages and disadvantages of all such resonant devices, as well as to such methods of control as the alpha, gamma, frequency control, capacitor voltage control, and state-plane trajectory control.

Chetty, P. R. K.

1992-04-01

376

D? scattering and D meson resonances from lattice QCD  

NASA Astrophysics Data System (ADS)

A first exploratory lattice QCD simulation is presented, aimed at extracting the masses and widths of the broad scalar D0*(2400) and the axial D1(2430) charm-light resonances. For that purpose D? and D*? scattering are simulated, and the resonance parameters are extracted using a Breit-Wigner fit of the resulting phase shifts. We use a single two-flavor dynamical ensemble with m??266MeV, a?0.124fm and a rather small volume V=163×32. The resulting D0*(2400) mass is 351±21MeV above the spin average (1)/(4)(mD+3mD*), in agreement with the experimental value of 347±29MeV above. The resulting D0*?D? coupling, glat=2.55±0.21GeV, is close to the experimental value gexp??1.92±0.14GeV, where g parametrizes the width ??g2p*/s. The resonance parameters for the broad D1(2430) are also found close to the experimental values; these are obtained by appealing to the heavy quark limit, where the neighboring resonance D1(2420) is narrow. The calculated I=1/2 scattering lengths are a0=0.81±0.14fm for D? and a0=0.81±0.17fm for D*? scattering. The simulation of the scattering in these channels incorporates quark-antiquark as well as multihadron interpolators, and the distillation method is used for contractions. In addition, the ground and several excited charm-light and charmonium states with various JP are calculated using standard quark-antiquark interpolators.

Mohler, Daniel; Prelovsek, Sasa; Woloshyn, R. M.

2013-02-01

377

Integrated surface plasmon resonance resonator using silicon on insulator  

NASA Astrophysics Data System (ADS)

We introduce an ultra-sensitive integrated photonic sensor structure using silicon on insulator based triangular resonator, in which a surface plasmon resonance (SPR) gold film is applied on a total internal reflection mirror. We have analyzed and optimized the triangular resonator sensor structure with an extremely small SPR mirror sensing area. Due to the large phase shift in the SPR mirror, a significantly enhanced sensitivity of 800 nm/RIU (refractive index unit) and the maximum peak shift of half free spectral range have been obtained at the SPR angle of 22.65° with Au thickness of 35 nm for the change of the refractive index ?n = 1x10-3.

Oh, Geum-Yoon; Kim, Doo-Gun; Kim, Seon Hoon; Ki, Hyun Chul; Kim, Tae Un; Kim, Hong-Seung; Lee, Tae-Kyeong; Lee, Byeong-Hyeon; Choi, Young-Wan

2013-03-01

378

Infrared Extraction Change for the NSLS-II Storage Ring  

SciTech Connect

The short- and long-range wakepotentials have been studied for the design of the infrared (IR) extraction chamber with large full aperture: 67mm vertical and 134mm horizontal. The IR-chamber will be installed within a 2.6m long wide-gap bending magnet with 25m bend radius. Due to the large bend radius it is difficult to separate the light from the electron trajectory. The required parameters of the collected IR radiation at the extraction mirror are {approx}50mrad horizontal and {approx}25mrad vertical (full radiation opening angles). If the extraction mirror is seen by the beam, resonant modes are generated in the chamber. In this paper, we present the detailed calculated impedance for the design of the far-IR chamber, and show that placing the extraction mirror in the proper position eliminates the resonances. In this case, the impedance reduces to that of a simple tapered structure, which is acceptable in regard to its impact on the electron beam.

Blednykh,A.; Carr, L.; Coburn, D.; Krinsky, S.

2009-05-04

379

URANIUM SOLVENT EXTRACTION PROCESS  

DOEpatents

A method is given for extracting uranium values from ores of high phosphate content consisting of dissolving them in aqueous nitric acid, adjusting the concentration of the aqueous solution to about 2 M with respect to nitric acid, and then contacting it with diethyl ether which has previously been made 1 M with respect to nitric acid.

Harrington, C.D.

1959-09-01

380

Matryoshka locally resonant sonic crystal.  

PubMed

The results of numerical modeling of sonic crystals with resonant array elements are reported. The investigated resonant elements include plain slotted cylinders as well as their various combinations, in particular, Russian doll or Matryoshka configurations. The acoustic band structure and transmission characteristics of such systems have been computed with the use of finite element methods. The general concept of a locally resonant sonic crystal is proposed that utilizes acoustic resonances to form additional band gaps that are decoupled from Bragg gaps. An existence of a separate attenuation mechanism associated with the resonant elements that increases performance in the lower frequency regime has been identified. The results show a formation of broad band gaps positioned significantly below the first Bragg frequency. For low frequency broadband attenuation, a most optimal configuration is the Matryoshka sonic crystal, where each scattering unit is composed of multiple concentric slotted cylinders. This system forms numerous gaps in the lower frequency regime, below Bragg bands, while maintaining a reduced crystal size viable for noise barrier technology. The finding opens alternative perspectives for the construction of sound barriers in the low frequency range usually inaccessible by traditional means including conventional sonic crystals. PMID:22087903

Elford, Daniel P; Chalmers, Luke; Kusmartsev, Feodor V; Swallowe, Gerry M

2011-11-01

381

Neural network diagnosis of avascular necrosis from magnetic resonance images  

NASA Astrophysics Data System (ADS)

We have explored the use of artificial neural networks to diagnose avascular necrosis (AVN) of the femoral head from magnetic resonance images. We have developed multi-layer perceptron networks, trained with conjugate gradient optimization, which diagnose AVN from single sagittal images of the femoral head with 100% accuracy on the training data and 97% accuracy on test data. These networks use only the raw image as input (with minimal preprocessing to average the images down to 32 X 32 size and to scale the input data values) and learn to extract their own features for the diagnosis decision. Various experiments with these networks are described.

Manduca, Armando; Christy, Paul S.; Ehman, Richard L.

1993-09-01

382

Fractal dimension of cerebral surfaces using magnetic resonance images  

SciTech Connect

The calculation of the fractal dimension of the surface bounded by the grey matter in the normal human brain using axial, sagittal, and coronal cross-sectional magnetic resonance (MR) images is presented. The fractal dimension in this case is a measure of the convolutedness of this cerebral surface. It is proposed that the fractal dimension, a feature that may be extracted from MR images, may potentially be used for image analysis, quantitative tissue characterization, and as a feature to monitor and identify cerebral abnormalities and developmental changes.

Majumdar, S.; Prasad, R.R.

1988-11-01

383

Effects of hot water extraction and fungal decay on wood crystalline cellulose structure  

Microsoft Academic Search

The effect of hot-water extraction and two types of fungal decay, brown rot and white rot, on wood crystalline cellulose structure\\u000a was examined using a combination of X-ray diffraction (XRD) and 13C solid-state nuclear magnetic resonance (NMR) spectroscopy. Although having opposite effects on the overall crystallinity\\u000a of the wood, the XRD results revealed that both extraction and brown-rot decay caused

Caitlin HowellAnne; Anne Christine Steenkjær Hastrup; Rory Jara; Flemming Hofmann Larsen; Barry Goodell; Jody Jellison

384

Accurate and robust extraction of brain regions using a deformable model based on radial basis functions  

Microsoft Academic Search

Brain extraction from head magnetic resonance (MR) images is a classification problem of segmenting image volumes into brain and non-brain regions. It is a difficult task due to the convoluted brain surface and the inapparent brain\\/non-brain boundaries in images. This paper presents an automated, robust, and accurate brain extraction method which utilizes a new implicit deformable model to well represent

Jia-Xiu Liu; Yong-Sheng Chen; Li-Fen Chen

2009-01-01

385

Precise damping and stiffness extraction in acoustic driven cantilever in liquid  

NASA Astrophysics Data System (ADS)

In this paper, we first explain how to extract accurately the driving force acting on the acoustic driven atomic force microscope cantilever in liquid from the measured resonance curve. We present a model that includes the driving force to extract precisely the damping and the stiffness of the tip sample interaction. The model is validated by an experimental test based on two independent methods to measure the hydrodynamic drag coefficient of a sphere moving perpendicular to flat surface.

Maali, Abdelhamid; Boisgard, Rodolphe

2013-10-01

386

Resonant Frequency Characteristics of a SAW Device Attached to Resonating Micropillars  

PubMed Central

Recently we reported experimental and simulation results on an increase in resonance frequency of a SAW resonator caused by mass loading of micropillars made of SU-8, attached normal to the surface of the resonator. We concluded that SAW resonator and the SU-8 micropillars in unison form a system of coupled resonators. We have now extended this work and performed a finite element method simulation to study the resonance frequency characteristics of the SAW-based coupled resonator. In this paper we report the effect of the resonance frequency of the micropillars on the resonance frequency of the system of coupled resonators, and observe the coupling of micropillar resonance and the propagating SAW as described in the well known Dybwad system of coupled resonators.

Ramakrishnan, N.; Nemade, Harshal B.; Palathinkal, Roy Paily

2012-01-01

387

Nd:YAG loop resonator with a Cr4+:YAG self-pumped phase-conjugate mirror  

Microsoft Academic Search

We demonstrate a Nd:YAG loop resonator with a self-pumped phase conjugate, mirror in a Cr4+:YAG crystal, in the nanosecond regime. A maximum extraction of 29 mJ and a maximum reflectivity of 3.3 are obtained. The output beam is a high-quality diffraction-limited TEM 00 mode and has a pulse shape of ~20-ns duration, showing the self Q-switching ability of the resonator.

Pierre Sillard; Arnaud Brignon; Jean-Pierre Huignard

1997-01-01

388

Multiple-tube resonance model  

NASA Astrophysics Data System (ADS)

In speech analysis, a recurring acoustical problem is the estimation of resonant structure of a tube of non-uniform cross-sectional area. We model such tubes as a finite sequence of cylindrical tubes of arbitrary, non-uniform length. From this model, we derive a closed form expression of the resonant structure of the model and analytically derive the boundary conditions for the case of a constant group delay. Since it has been noted in the literature that the group delay of the vocal tract is constant, these boundary conditions hold for the vocal tract. In the limiting case, the non-uniform tube model reduces the well studied uniform tube model. For this limiting case, we derive an expression of the tube resonant structure in terms of a Fourier transform. Finally, we derive wave equations from the model, which are consistent with the wave equations for the telegraph wire problem.

Smith, Lawrence H.; Nelson, Douglas J.

2002-12-01

389

Dissipative forces and external resonances  

NASA Astrophysics Data System (ADS)

We analyze the process of resonance trapping due to Poynting-Robertson drag and Stokes drag in the frame of the restricted 3-body problem and in the case of external mean motion resonances. The numerical simulations presented are computed by using the 3-dimensional extended Schubart averaging (ESA) integrator developed by Moons (1994) for all mean motion resonances. We complete it by adding the contributions of the dissipative forces. To follow the philosophy of the initial integrator, we average the drag terms, but we do not make any expansion in series of eccentricity or inclination. We show our results, especially capture around asymmetric equilibria, and compare them to those found by Beaué and Ferraz-Mello (1993, 1994) and Liou et al. (1979).

Jancart, Sylvie; Lemaitre, Anne

390

Discussion of human resonant frequency  

NASA Astrophysics Data System (ADS)

Human bodies are often exposed to vertical vibrations when they are in the workplace or on vehicles. Prolonged exposure may cause undue stress and discomfort in the human body especially at its resonant frequency. By testing the response of the human body on a vibrating platform, many researchers found the human whole-body fundamental resonant frequency to be around 5 Hz. However, in recent years, an indirect method has been prosed which appears to increase the resonant frequency to approximately 10 Hz. To explain this discrepancy, experimental work was carried out in NTU. The study shows that the discrepancy lies in the vibration magnitude used in the tests. A definition of human natural frequency in terms of vibration magnitude is proposed.

Brownjohn, James M.; Zheng, Xiahua

2001-06-01

391

Viscoelastic coupling of nanoelectromechanical resonators.  

SciTech Connect

This report summarizes work to date on a new collaboration between Sandia National Laboratories and the California Institute of Technology (Caltech) to utilize nanoelectromechanical resonators designed at Caltech as platforms to measure the mechanical properties of polymeric materials at length scales on the order of 10-50 nm. Caltech has succeeded in reproducibly building cantilever resonators having major dimensions on the order of 2-5 microns. These devices are fabricated in pairs, with free ends separated by reproducible gaps having dimensions on the order of 10-50 nm. By controlled placement of materials that bridge the very small gap between resonators, the mechanical devices become coupled through the test material, and the transmission of energy between the devices can be monitored. This should allow for measurements of viscoelastic properties of polymeric materials at high frequency over short distances. Our work to date has been directed toward establishing this measurement capability at Sandia.

Simonson, Robert Joseph; Staton, Alan W.

2009-09-01

392

Two-photon resonance fluorescence  

SciTech Connect

We present a theory of two-photon resonance fluorescence of an atom or molecule in which the excitation by an external electromagnetic field as well as fluorescence emission is mediated by two-photon processes. The treatment is based on first dressing the atom or molecule by the external field and then evaluating perturbatively the effect of the interaction with the vacuum or fluorescent field and so resonance fluorescence can be considered as spontaneous emission from the dressed atom. The introduction of the combined system of atom and external field via dressed states leads to simpler calculations and more transparent physics. The fluorescence spectrum derived by us has similarities as well as differences with that of one-photon resonance fluorescence and earlier theoretical predictions for the two-photon case.

Alexanian, Moorad; Bose, Subir K. [Department of Physics and Physical Oceanography, University of North Carolina Wilmington, Wilmington, North Carolina 28403 (United States); Department of Physics, University of Central Florida, Orlando, Florida 32816 (United States)

2006-12-15

393

Wavenumber Resonance in Nonlinear Wave Interactions in the Wake of a Flat Plate.  

NASA Astrophysics Data System (ADS)

The spatial characteristics of nonlinear wave interactions in transitioning flow in the symmetric wake of a flat plate were studied. The investigation combines the use of hot-wire anemometry and newly developed digital analysis techniques for extracting frequency and wavenumber information from velocity fluctuation time series measurements. The linear spatial coherence was computed from velocity fluctuation data in order to determine if the frequency modes behave as waves, that is, spatially coherent fluctuations with a well-defined dispersion relation. The auto-bicoherence, which is primarily a measure of temporal phase coherence among frequency-resonant mode triads, was calculated in order to determine which modes are quadratically coupled. Also, a new method was used to compute the mode triad wavenumber mismatch. The results were used to determine to what extent wavenumber resonance is present among quadratically interacting frequency-resonant modes, as predicted by resonant wave interaction theory. The results show that, in the early part of the transition, instability modes interact nonlinearly to generate spatially coherent modes at frequencies above the instability range. Quadratically interacting, frequency-resonant mode triads involved in the transfer of energy to the harmonics of the fundamental instability exhibit good wavenumber resonance, as predicted by resonant wave interaction theory. This indicates that nonlinear resonant interactions among spatially coherent waves characterize the early development of the transition. As transition progresses, the wavenumber of each mode begins to behave as a stochastic variable with a multivalued distribution. The results suggest that the onset of this behavior is caused by the multiplicity of interacting frequency-resonant triads in which each mode participates. As the turbulent region is approached, the modes lose spatial coherence, and auto-bicoherence values drop. This indicates that the final stage of transition to turbulence involves a change in the character of nonlinear interactions that does not allow for them to be described by resonant wave theory.

Dacaron, Davila; Benigno, Jose

1990-01-01

394

Giant resonances: Progress, new directions, new challenges  

SciTech Connect

A review of some recent developments in the field of giant multipole resonances is presented. Particular emphasis is placed on directions that the authors feel will be followed in this field during the next several years. In particular, the use of high-energy heavy ions to excite the giant resonances is shown to provide exciting new capabilities for giant resonance studies. Among subjects covered are: Coulomb excitation of giant resonances, photon decay of giant resonances, the recent controversy over the identity of the giant monopole resonance, the most recent value for incompressibility of nuclear matter from analysis of giant monopole data, the isospin character of the 63 A/sup /minus/1/3/ GQR, agreement between (e,e/prime/) and (hadron, hadron/prime/) excitation of the giant quadrupole resonance, prospects for multiphonon giant resonance observation, and isolation of the isovector giant quadrupole resonance. 55 refs., 23 figs., 4 tabs.

Bertrand, J.R.; Beene, J.R.

1989-01-01

395

Enhanced antibacterial activities of leonuri herba extracts containing silver nanoparticles.  

PubMed

We report an efficient and powerful green process to enhance the antibacterial activities of the Leonuri herba extract. Plant sources, especially leaves and herbs, are precious for the generation of gold and silver nanoparticles. Various kinds of polyphenols and hydroxyl groups are capable of processing a reduction reaction to generate metals from its corresponding salts. We have prepared gold and silver nanoparticles with 70% ethanol and water extracts. No other toxic chemicals were utilized and the extracts played dual roles as reducing and stabilizing agents. For the generation of nanoparticles, both oven incubation and autoclaving methods were applied and the reaction conditions were optimized. Surface plasmon resonance band indicated that the formation of nanoparticles was successful. Images of high-resolution transmission electron microscopy revealed mostly spherical nanoparticles ranging from 9.9 to 13.0?nm in size. A water extract containing silver nanoparticles exhibited remarkable (approximately 127-fold) enhancement in antibacterial activities against Pseudomonas aeruginosa, Escherichia coli and Enterobacter cloacae when compared with the water extract alone. In addition, antibacterial activity towards Gram-negative bacteria was greater than that against Gram-positive bacteria. The process reported here has the potential to be a new approach to improve the antibacterial activities of plant extracts. PMID:22170803

Im, A-Rang; Han, Lina; Kim, E Ray; Kim, Jinwoong; Kim, Yeong Shik; Park, Youmie

2011-12-15

396

Photon Localization in Resonant Media  

NASA Astrophysics Data System (ADS)

Unlike electrons that can be trapped by the Coulomb interaction at atomic sites, photons are not bound by individual particles. They may, however, be strongly scattered at Mie resonances, with the scattering cross section considerably exceeding the geometric cross section. We utilize Mie resonances to localize microwave radiation in low-density quasi-one dimensional samples of randomly positioned dielectric spheres. We explore factors that facilitate photon localization and probe the properties of localized waves. Sharp dips in the ensemble average of transmission and peaks in the average photon transit time are found near the first five Mie resonances. A decisive statistical test of photon localization, based on measurements of the variance of the intensity normalized by its ensemble average value, shows, however, that localization occurs only in a narrow window above the first Mie resonance. Measurements of this localization parameter are compared to measurements of the dimensionless conductance and of the Thouless number in samples with and without absorption. The Thouless number, which is the ratio of the width to the spacing of quasi-modes of a random medium, is obtained from measurements of the field correlation function with frequency shift and of the spacing between resonances in a sealed cavity. In samples with negligible absorption, these parameters coincide. The localization parameters reach a minimum within the window of localization as a result of collective scattering. In the presence of absorption, only the variance of intensity remains a reliable guide to localization. When the sample is cooled to 77 K to reduce absorption, narrow Lorentzian transmission peaks are observed as a result of resonant tunneling through long-lived localized modes. The enhancement of intensity in long-lived modes as the localization threshold is approached is related to sharp line lasing in random amplifying media. In collaboration with Andrey Chabanov.

Genack, Azriel

2002-03-01

397

Thermal resonance in signal transmission  

SciTech Connect

We use temperature tuning to control signal propagation in simple one-dimensional arrays of masses connected by hard anharmonic springs and with no local potentials. In our numerical model a sustained signal is applied at one site of a chain immersed in a thermal environment and the signal-to-noise ratio is measured at each oscillator. We show that raising the temperature can lead to enhanced signal propagation along the chain, resulting in thermal resonance effects akin to the resonance observed in arrays of bistable systems.

Reigada, Ramon; Sarmiento, Antonio; Lindenberg, Katja

2001-06-01

398

Gallium nitride nanowire electromechanical resonators  

NASA Astrophysics Data System (ADS)

Nanoscale mechanical resonators are of great interest for high-resolution sensing applications, where the small resonator mass and high quality factor (Q, defined as resonance frequency f0 over full width at half maximum power) lead to unprecedented sensitivity. Here, we investigate gallium nitride (GaN) nanowire (NW) resonators. The single-crystal, c-axis NWs are 5 mum -- 20 mum long, with diameters from 50 nm -- 500 nm, and grow essentially free of defects. Our initial experiments involve measuring the resonances of as-grown NWs in a scanning electron microscope, where we observe exceptionally high Q values of 10 4 -- 105, one to two orders of magnitude higher than most NWs of comparable size. Using a single NW as a mass sensor, we then demonstrate a sub-attogram mass sensitivity. To provide a more flexible measurement technique that avoids electron-microscope detection, we fabricate doubly clamped NWs with an entirely electronic drive and readout scheme using a combination of lithographic patterning and dielectrophoresis. An electrostatic gate induces vibration, while readout utilizes the piezoresistivity of GaN. Observed resonances range from 9--36 MHz with Q values typically around 103 at room temperature and 10 -4 Pa. We use the behavior of f0 and Q to sense the NW's local environment, such as the additional sources of energy dissipation not present in the as-grown NWs. By cooling the device to 8 K, Q increases by an order of magnitude to above 104, with a highest value to date of 26,000 under vacuum. We explore additional NW properties through the thermal noise in the NW's mechanical motion and the exponential decay of mechanical motion in the presence of burst drive. Finally, we investigate the low-frequency 1/f parameter noise displayed by f0. We show that the noise in f0 is consistent with noise in the NW's resistance leading to temperature noise from local Joule heating, which in turn generates resonance frequency noise. For sensor applications, there will be optimal drive conditions that balance the f 0 noise with the signal-to-noise ratio of the system. With these insights, along with the simple drive and readout technique, these GaN-NW doubly clamped resonators have significant potential for high-resolution sensing applications.

Gray, Jason Michael

399

Integrated silicon optofluidic ring resonator  

NASA Astrophysics Data System (ADS)

The feasibility of an integrated silicon optofluidic ring resonator is demonstrated. Liquid core antiresonant reflecting optical waveguides are used to realize a rectangular ring resonator with a multimode interference liquid core coupler between the ring and the bus waveguide. In this configuration the same waveguide used to confine the light is able to deliver the liquid sample without the need for any additional microfluidics, resulting in a very compact device with a required liquid volume of about 0.11 nl. Optical characterization shows that ring with a good quality factor (Q~800) can be achieved in good agreement with the numerical results.

Testa, Genni; Huang, Yujian; Sarro, Pasqualina M.; Zeni, Luigi; Bernini, Romeo

2010-09-01

400

Whispering gallery mode diamond resonator.  

PubMed

We demonstrate a nearly spherical diamond whispering gallery mode resonator with quality factor (Q factor) Q=2.4×107 limited by material loss approaching ?=4×10-3??cm-1. The Q factor does not depend on the wavelength: it is approximately the same at 1319 and 1550 nm. Resonators with this range of Q (<10??MHz at 1550 nm wavelength) are attractive for laser locking and stabilization. Applications such as stable compact optical comb generators as well as Raman optical frequency shifters will be feasible with further improvement of the material. PMID:24177083

Ilchenko, V S; Bennett, A M; Santini, P; Savchenkov, A A; Matsko, A B; Maleki, L

2013-11-01

401

Metamaterial resonators on curved surfaces  

NASA Astrophysics Data System (ADS)

Straightforward extension of canonical microwave metamaterial structures to optical and IR frequency dimensions is complicated by both the size scale of the resulting structures, requiring cutting edge lithography to achieve the requisite line-widths, as well as limitations on assembly/construction into final geometry. We present a scalable fabrication approach capable of generating metamaterial structures such as split ring resonators and split wire pairs on a micron/sub-micron size scale on concave surfaces with a radius of curvature ~ SRR diameter. This talk outlines the fabrication method and modeling/theory based interpretation of the implications of curved metamaterial resonators.

Burckel, D. B.; Davids, P.; Brener, I.; Ten Eyck, G. A.; Ellis, A. R.; Wendt, J. R.; Passmore, B. S.; Shaner, E. A.; Sinclair, M. B.

2009-08-01

402

Interventional Cardiovascular Magnetic Resonance Imaging  

PubMed Central

Cardiovascular magnetic resonance (CMR) combines excellent soft-tissue contrast, multiplanar views, and dynamic imaging of cardiac function without ionizing radiation exposure. Interventional cardiovascular magnetic resonance (iCMR) leverages these features to enhance conventional interventional procedures or to enable novel ones. Although still awaiting clinical deployment, this young field has tremendous potential. We survey promising clinical applications for iCMR. Next, we discuss the technologies that allow CMR-guided interventions and, finally, what still needs to be done to bring them to the clinic.

Saikus, Christina E.; Lederman, Robert J.

2010-01-01

403

Secondary resonance magnetic force microscopy  

NASA Astrophysics Data System (ADS)

In this study, we have developed secondary resonance magnetic force microscopy (SR-MFM) for imaging alternating magnetic fields from a sample surface at the secondary resonant frequency of the magnetic cantilever at the same time as the topographic image. SR-MFM images of alternating magnetic fields diverging from the main pole in a driving perpendicular magnetic recording head are presented, and the divergence and convergence of the fields are discussed. The spatial resolution of SR-MFM is estimated to be 18 nm this is 2.5 times smaller than that of conventional MFM.

Tanaka, Suguru; Azuma, Yasuo; Majima, Yutaka

2012-04-01

404

Stochastic resonance in electrical circuits. I. Conventional stochastic resonance  

Microsoft Academic Search

Stochastic resonance (SR), a phenomenon in which a periodic signal in a nonlinear system can be amplified by added noise, is introduced and discussed. Techniques for investigating SR using electronic circuits are described in practical terms. The physical nature of SR, and the explanation of weak-noise SR as a linear response phenomenon, are considered. Conventional SR, for systems characterized by

Dmitrii G. Luchinsky; Riccardo Mannella; Peter V. E. McClintock; Nigel G. Stocks

1999-01-01

405

Cavity-resonator-integrated guided-mode resonance filters  

NASA Astrophysics Data System (ADS)

A cavity-resonator-integrated guided-mode-resonance filter (CRIGF) consisting of a grating coupler (GC) and a pair of distributed-Bragg-reflectors (DBRs) on a thin-film dielectric waveguide is reviewed. The CRIGF has been recently proposed by the authors to provide a narrow-band reflection spectrum for an incident wave of a small beam width from the free space. A newly developed analysis model for device design with performance simulation is introduced. Curved gratings are utilized to construct a resonator for a small-aperture CRIGF. Design, fabrication and characterization of CRIGFs of 10 ?m aperture are described with a resonance wavelength of 850 nm. A Ge:SiO2 guiding core layer was deposited on a SiO2 glass substrate, and GC and DBRs were formed by the electron-beam direct writing lithography. A normal polarization-dependent CRIGF is shown with a obtained narrowband reflection spectrum of 0.2 nm full width at half maximum. A crossed-CRIGF is also discussed to eliminate the polarization dependence. It is successfully demonstrated that measured reflection spectra for TE and TM incident beams were well coincident with each other.

Ura, Shogo; Kintaka, Kenji; Inoue, Junichi; Nishio, Kenzo; Awatsuji, Yasuhiro

2013-03-01

406

Wavelength-tunable optical ring resonators  

DOEpatents

Optical ring resonator devices are disclosed that can be used for optical filtering, modulation or switching, or for use as photodetectors or sensors. These devices can be formed as microdisk ring resonators, or as open-ring resonators with an optical waveguide having a width that varies adiabatically. Electrical and mechanical connections to the open-ring resonators are made near a maximum width of the optical waveguide to minimize losses and thereby provide a high resonator Q. The ring resonators can be tuned using an integral electrical heater, or an integral semiconductor junction.

Watts, Michael R. (Albuquerque, NM); Trotter, Douglas C. (Albuquerque, NM); Young, Ralph W. (Albuquerque, NM); Nielson, Gregory N. (Albuquerque, NM)

2011-07-19

407

Wavelength-tunable optical ring resonators  

DOEpatents

Optical ring resonator devices are disclosed that can be used for optical filtering, modulation or switching, or for use as photodetectors or sensors. These devices can be formed as microdisk ring resonators, or as open-ring resonators with an optical waveguide having a width that varies adiabatically. Electrical and mechanical connections to the open-ring resonators are made near a maximum width of the optical waveguide to minimize losses and thereby provide a high resonator Q. The ring resonators can be tuned using an integral electrical heater, or an integral semiconductor junction.

Watts, Michael R. (Albuquerque, NM); Trotter, Douglas C. (Albuquerque, NM); Young, Ralph W. (Albuquerque, NM); Nielson, Gregory N. (Albuquerque, NM)

2009-11-10

408

SNAKE DEPLORIZING RESONANCE STUDY IN RHIC  

SciTech Connect

Snake depolarizing resonances due to the imperfect cancellation of the accumulated perturbations on the spin precession between snakes were observed at the Relativistic Heavy Ion Collider (RHIC). During the RHIC 2005 and 2006 polarized proton runs, we mapped out the spectrum of odd order snake resonance at Q{sub y} = 7/10. Here, Q, is the beam vertical betatron tune. We also studied the beam polarization after crossing the 7/10th resonance as a function of resonance crossing rate. This paper reports the measured resonance spectrum as well as the results of resonance crossing.

BAI,M.; CAMERON, P.; LUCCIO, A.; HUANG, H.; PITISYN, V.; ET AL.

2007-06-25

409

Relationship between Fermi Resonance and Solvent Effects  

NASA Astrophysics Data System (ADS)

We theoretically and experimentally study the relationship between Fermi resonance and solvent effects and investigate the Fermi resonance of p-benzoquinone and cyclopentanone in different solvents and the Fermi resonance of CS2 in C6H6 at different concentrations. Also, we investigate the Fermi resonance of C6H6 and CCl4 in their solution at different pressures. It is found that solvent effects can be utilized to search Fermi resonance parameters such as coupling coefficient and spectral intensity ratio, etc., on the other hand, the mechanism of solvent effects can be revealed according to Fermi resonance at high pressure.

Jiang, Xiu-Lan; Li, Dong-Fei; Sun, Cheng-Lin; Li, Zhan-Long; Yang, Guang; Zhou, Mi; Li, Zuo-Wei; Gao, Shu-Qin

2011-05-01

410

Integrated modeling of electron cyclotron resonance ion sources and charge breeders with GEM, MCBC, and IonEx  

SciTech Connect

A numerical toolset to help in understanding physical processes in the electron cyclotron resonance charge breeder (ECRCB) and further to help optimization and design of current and future machines is presented. The toolset consists of three modules (Monte Carlo charge breeding code, generalized electron cyclotron resonance ion source modeling, and ion extraction), each modeling different processes occurring in the ECRCB from beam injection to extraction. The toolset provides qualitative study, such as parameter studies, and scaling of the operation, and physical understanding in the ECRCB. The methodology and a sample integrated modeling are presented.

Kim, J. S.; Zhao, L.; Cluggish, B. P.; Galkin, S. A.; Grubert, J. E. [FAR-TECH, Inc., 3550 General Atomics Court, MS 15-155, San Diego, California 92121 (United States); Pardo, R. C.; Vondrasek, R. C. [Argonne National Laboratory, Argonne, Illinois 60439 (United States)

2010-02-15

411

Automatic Event Type Extraction in Chinese Event Extraction  

Microsoft Academic Search

Event Extraction is a new research point in the area of Information Extraction. In this paper, we carried out a series of experiments on event detection and classification based on the standard and training corpus of ACE05 (Automatic Content Extraction 2005), which is a research task organized by NIST (National Institute of Standards and Technology). In the experiment, a table

Yanyan Zhao; Xiaoyin Wang; Bing Qin; Wanxiang Che; Ting Liu

412

LIPID EXTRACTION FROM WHEAT FLOUR USING SUPERCRITICAL FLUID EXTRACTION  

Technology Transfer Automated Retrieval System (TEKTRAN)

Environmental concerns, the disposal cost of hazardous waste, and the time required for extraction encouraged us to look for a method to extract lipids from wheat flour that would be faster, less costly, and more environmentally acceptable. Supercritical Fluid Extraction (SFE) with carbon dioxide (...

413

after Supercritical Fluid Extraction  

Microsoft Academic Search

Six monoterpenes (?-pinene, ?-pinene, 3-carene, phellandrene, camphene, and limonene) were determined in the needles of Picea abies, P. omorica ,a ndP. pungens spruces by gas chromatogra- phy after supercritical fluid extraction (SFE) with carbon dioxide at the pressure 20 MPa and at the temperature 80 ?C. Significant differences among the monoterpene content of individual spruce cultivars were found. Limonene (34.3

J. SEDLÁKOVÁ; L. LOJKOVÁ; V. KUBÁ?

414

Semantics Extraction from Images  

Microsoft Academic Search

\\u000a An overview of the state-of-the-art on semantics extraction from images is presented. In this survey, we present the relevant\\u000a approaches in terms of content representation as well as in terms of knowledge representation. Knowledge can be represented\\u000a in either implicit or explicit fashion while the image is represented in different levels, namely, low-level, intermediate\\u000a and semantic level. For each combination

Ioannis Pratikakis; Anastasia Bolovinou; Bassilios Gatos; Stavros J. Perantonis

2011-01-01

415

Solid phase extraction membrane  

DOEpatents

A wet-laid, porous solid phase extraction sheet material that contains both active particles and binder and that possesses excellent wet strength is described. The binder is present in a relatively small amount while the particles are present in a relatively large amount. The sheet material is sufficiently strong and flexible so as to be pleatable so that, for example, it can be used in a cartridge device.

Carlson, Kurt C [Nashville, TN; Langer, Roger L [Hudson, WI

2002-11-05

416

URANIUM EXTRACTION PROCESS  

DOEpatents

A process is described for recovering uranium values from acidic aqueous solutions containing hexavalent uranium by contacting the solution with an organic solution comprised of a substantially water-immiscible organlc diluent and an organic phosphate to extract the uranlum values into the organic phase. Carbon tetrachloride and a petroleum hydrocarbon fraction, such as kerosene, are sultable diluents to be used in combination with organlc phosphates such as dibutyl butylphosphonate, trlbutyl phosphine oxide, and tributyl phosphate.

Baldwin, W.H.; Higgins, C.E.

1958-12-16

417

Neural Network Knowledge Extraction  

Microsoft Academic Search

The usage of ANNs in "safety-critical" domains, which include theeconomic and financial applications, is hindered by their "black box"- type approach,which makes it difficult to verify and debug software that includes ANNcomponents. Significant advantages can be gained by combining the symbolic knowledgeof a domain theory (DT), with the empirical sub-symbolic knowledge stored in an ANNtrained on examples. Rule extraction adds

Alexandra I. Cristea; Paul D. Cristea; Toshio Okamoto

1997-01-01

418

Multichannel R-matrix analysis of elastic and inelastic resonances in the {sup 21}Na+ p compound system  

SciTech Connect

A multichannel R-matrix formalism was used to fit {sup 21}Na+ p resonant elastic and inelastic scattering data taken at the TRIUMF UK detector array facility at TRIUMF-ISAC. Five resonances were observed corresponding to states in {sup 22}Mg above the proton threshold. Four of these corresponded to states seen in previous transfer reaction studies where firm spin-parity assignments could not be made. One new resonance, previously unobserved in any reaction, was also seen. Where possible, resonance energies, partial widths, and spin-parity values of these resonances were extracted. The correspondence between these states and possible analogs in the mirror nucleus {sup 22}Ne is discussed, as well as the relation to T=1 states in the nucleus {sup 22}Na.

Ruiz, C.; Davinson, T.; Sarazin, F.; Roberts, I.; Robinson, A.; Woods, P.J.; Buchmann, L.; Shotter, A.C.; Walden, P.; Clarke, N.M.; Chen, A.A.; Fulton, B.R.; Groombridge, D.; Pearson, J.; Murphy, A.S. [University of Edinburgh, Edinburgh, EH9 3JZ (United Kingdom); TRIUMF, Vancouver, BC V6T 2A3 (Canada); University of Birmingham, Birmingham B15 2TT (United Kingdom); Simon Fraser University, Burnaby, BC V5A 1S6 (Canada); University of York, York YO10 5DD (United Kingdom); Ohio State University, Columbus, Ohio (United States)

2005-02-01

419

NDI using mm-wave resonant techniques  

NASA Astrophysics Data System (ADS)

Millimeter wave resonant measurements are commonly used for surface and near-surface materials characterization including the detection of cracks and defects, analysis of semiconducting and dielectric materials, and analysis of metallic electrical properties beneath coatings. Recent work has also shown the approach to be useful in evaluating corrosion products and the detection of incipient corrosion and corrosion cracking. In the analysis area, complex permittivity data of the corrosion products can be extracted, usually with accuracy of a few percent or better, to aid in identification of the product and possibly of mechanisms. In the detection area, corrosion-related cracks of order 100 microns or less near the surface have been detected and corrosion products have been detected beneath a variety of paints. Surface preparation requirements are minimal, particularly compared to some optical techniques, giving increased hope of field applicability. A number of examples of NDI on aircraft related materials and structures will be presented along with an assessment of detection and accuracy limits.

Martens, J. S.; Sachtjen, S.; Sorensen, N. R.

1995-08-01

420

Segmentation of neuroanatomy in magnetic resonance images  

NASA Astrophysics Data System (ADS)

Segmentation in neurological magnetic resonance imaging (MRI) is necessary for feature extraction, volume measurement and for the three-dimensional display of neuroanatomy. Automated and semi-automated methods offer considerable advantages over manual methods because of their lack of subjectivity, their data reduction capabilities, and the time savings they give. We have used dual echo multi-slice spin-echo data sets which take advantage of the intrinsically multispectral nature of MRI. As a pre-processing step, a rf non-uniformity correction is applied and if the data is noisy the images are smoothed using a non-isotropic blurring method. Edge-based processing is used to identify the skin (the major outer contour) and the eyes. Edge-focusing has been used to significantly simplify edge images and thus allow simple postprocessing to pick out the brain contour in each slice of the data set. Edge- focusing is a technique which locates significant edges using a high degree of smoothing at a coarse level and tracks these edges to a fine level where the edges can be determined with high positional accuracy. Both 2-D and 3-D edge-detection methods have been compared. Once isolated, the brain is further processed to identify CSF, and, depending upon the MR pulse sequence used, the brain itself may be sub-divided into gray matter and white matter using semi-automatic contrast enhancement and clustering methods.

Simmons, Andrew; Arridge, Simon R.; Barker, G. J.; Tofts, Paul S.

1992-06-01

421

Extraction of Iron with Methylethylketone.  

National Technical Information Service (NTIS)

The extraction of iron (III) with methylethylketone as solvent from hydrochloric acid solution is described, and the maximum range of acid concentration for quantitative extraction was determined. Most of the elements of the third analytical group were in...

E. Gagliardi H. P. Woess

1974-01-01

422

Direct-Coupled-Resonator Filters  

Microsoft Academic Search

A new analysis is given of direct-coupled-resonator filters that results in excellent response at much greater bandwidths than has previously been possible. The method relies on the fact that the coupling elements can be made into perfect impedance inverters, or \\

Seymour Cohn

1957-01-01

423

Bulk Acoustic Resonator Tracking Filter.  

National Technical Information Service (NTIS)

This invention is directed to a narrow band filter for eliminating out-of-band noise in the oscillator signal of a doppler radar system. It provides a very high Q filter derived from a Bulk Acoustic Resonator's (BAR) high Q, L-Band response and uses therm...

M. S. Buchalter

1984-01-01

424

Surface plasmon resonance sensors: review  

Microsoft Academic Search

Since the first application of the surface plasmon resonance (SPR) phenomenon for sensing almost two decades ago, this method has made great strides both in terms of instrumentation development and applications. SPR sensor technology has been commercialized and SPR biosensors have become a central tool for characterizing and quantifying biomolecular interactions. This paper attempts to review the major developments in

Ji??? Homola; Sinclair S. Yee; Günter Gauglitz

1999-01-01

425

Waveguide surface plasmon resonance sensors  

Microsoft Academic Search

Planar waveguide surface plasmon resonance sensors have great potential for use in the field of environmental monitoring. In this paper we present a rigorous model for the optical power transmittance of this type of sensor. This model is used to determine the change in transmitted power when a thin layer is adsorbed to the metal-clad region of the sensor, as

R. D. Harris; J. S. Wilkinson

1995-01-01

426

Controlling chaos in ferromagnetic resonance  

Microsoft Academic Search

The chaotic response of yttirum iron garnet (YIG) films in high-power ferromagnetic resonance (FMR) has been successfully controlled in experiments using a time-delayed control method. The ac component of the FMR signal was delayed and used to perturb a system parameter, the static magnetic field. The application of the perturbations initially modified the chaotic oscillations in the FMR absorption signal,

P. E. Wigen; M. Ye; D. W. Peterman

1995-01-01

427

Stochastic resonance on a circle  

SciTech Connect

We describe a new realization of stochastic resonance, applicable to a broad class of systems, based on an underlying excitable dynamics with deterministic reinjection. A simple but general theory of such single-trigger'' systems is compared with analog simulations of the Fitzhugh-Nagumo model, as well as experimental data obtained from stimulated sensory neurons in the crayfish.

Wiesenfeld, K. (School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)); Pierson, D.; Pantazelou, E.; Dames, C.; Moss, F. (Department of Physics, University of Missouri at St. Louis, St. Louis, Missouri 63121 (United States))

1994-04-04

428

Model for resonant plasma probe.  

SciTech Connect

This report constructs simple circuit models for a hairpin shaped resonant plasma probe. Effects of the plasma sheath region surrounding the wires making up the probe are determined. Electromagnetic simulations of the probe are compared to the circuit model results. The perturbing effects of the disc cavity in which the probe operates are also found.

Warne, Larry Kevin; Johnson, William Arthur; Hebner, Gregory Albert; Jorgenson, Roy E.; Coats, Rebecca Sue

2007-04-01

429

Harmonic Multiplication Using Resonant Tunneling,  

National Technical Information Service (NTIS)

We propose and demonstrate an odd-harmonic resistive multiplier that exploits the unique current-voltage (I-V) relation of resonant-tunneling diodes. It is shown that efficient odd-harmonic conversion is possible and that even harmonics do not appear beca...

T. C. Sollner E. R. Brown W. D. Goodhue C. A. Correa

1988-01-01

430

Cyclotron resonance of trilayer graphene  

NASA Astrophysics Data System (ADS)

The cyclotron resonance energies, the corresponding oscillator strengths, and the cyclotron absorption spectrum for trilayer graphene are calculated for both ABA and ABC stacking. A gate potential across the stacked layers leads to (1) a reduction of the transition energies, (2) a lifting of the degeneracy of the zero Landau level, and (3) the removal of the electron-hole symmetry.

Sena, S. H. R.; Pereira, J. M., Jr.; Farias, G. A.; Peeters, F. M.

2012-08-01

431

Micromachined Acoustic Resonant Mass Sensor  

Microsoft Academic Search

This paper describes a highly sensitive, film bulk acoustic resonator (FBAR) mass sensor (built on a micromachined silicon-nitride diaphragm with a piezoelectric thin film and Al electrodes) that can operate in vapor and liquid. The sensitivity of the device to mass change on its surface has been investigated by having various thicknesses of silicon-nitride support layer and also of Al

Hao Zhang; Eun Sok Kim

2005-01-01

432

Magnetic resonance imaging in medicine  

Microsoft Academic Search

Over the past twenty years, magnetic resonance imaging (MRI) has become one of the most important imaging modalities available to clinical medicine. It offers great technical flexibility, and is free of the hazards associated with ionizing radiation. In addition to its role as a routine imaging technique with a growing range of clinical applications, the pace of development in MRI

Stephen F. Keevil

2001-01-01

433

Stochastic resonance on a circle  

NASA Astrophysics Data System (ADS)

We describe a new realization of stochastic resonance, applicable to a broad class of systems, based on an underlying excitable dynamics with deterministic reinjection. A simple but general theory of such ``single-trigger'' systems is compared with analog simulations of the Fitzhugh-Nagumo model, as well as experimental data obtained from stimulated sensory neurons in the crayfish.

Wiesenfeld, Kurt; Pierson, David; Pantazelou, Eleni; Dames, Chris; Moss, Frank

1994-04-01

434

Duffing's Equation and Nonlinear Resonance  

ERIC Educational Resources Information Center

The phenomenon of nonlinear resonance (sometimes called the "jump phenomenon") is examined and second-order van der Pol plane analysis is employed to indicate that this phenomenon is not a feature of the equation, but rather the result of accumulated round-off error, truncation error and algorithm error that distorts the true bounded solution onto…

Fay, Temple H.

2003-01-01

435

Secular resonance in extrasolar system  

Microsoft Academic Search

The two orbits in the HD 160691 planetary system at first appeared highly unstable, but using a new technique called MEGNO (the acronym of Mean Exponential Growth factor of Nearby Orbits), we were able to identify a stability valley in the parameter space. This stability zone is due to the 2:1 mean motion resonance coupled with relative orbital positions of

N. Rambaux; E. Bois

2003-01-01

436

Composite Resonator Surface Emitting Lasers  

SciTech Connect

The authors have developed electrically-injected coupled-resonator vertical-cavity lasers and have studied their novel properties. These monolithically grown coupled-cavity structures have been fabricated with either one active and one passive cavity or with two active cavities. All devices use a selectively oxidized current aperture in the lower cavity, while a proton implant was used in the active-active structures to confine current in the top active cavity. They have demonstrated optical modulation from active-passive devices where the modulation arises from dynamic changes in the coupling between the active and passive cavities. The laser intensity can be modulated by either forward or reverse biasing the passive cavity. They have also observed Q-switched pulses from active-passive devices with pulses as short as 150 ps. A rate equation approach is used to model the Q-switched operation yielding good agreement between the experimental and theoretical pulseshape. They have designed and demonstrated the operation of active-active devices which la.se simultaneously at both longitudinal cavity resonances. Extremely large bistable regions have also been observed in the light-current curves for active-active coupled resonator devices. This bistability can be used for high contrast switching with contrast ratios as high as 100:1. Coupled-resonator vertical-cavity lasers have shown enhanced mode selectivity which has allowed devices to lase with fundamental-mode output powers as high as 5.2 mW.

FISCHER,ARTHUR J.; CHOQUETTE,KENT D.; CHOW,WENG W.; ALLERMAN,ANDREW A.; GEIB,KENT M.

2000-05-01

437

Injecting Asteroid Fragments into Resonances.  

National Technical Information Service (NTIS)

We have quantitatively modeled the chance insertion of asteroid collisional fragments into the 3:1 and g = g(sub 6) resonances, through which they can achieve Earth-approaching orbits. Although the results depend on some poorly known parameters, they indi...

P. Farinella R. Gonczi C. Froeschle C. Froeschle

1992-01-01

438

Resonance phenomena in fluid media  

Microsoft Academic Search

Studies were made to detect the presence of a memory in fluid media. The experiments revealed that the effect of electromagnetic radiation on fluid media can be explained by the phenomenon of resonant response of the system receiving the radiation. Studies were made on plant seeds and yeasts, accompanied by catalytic chemical reactions and several physical and chemical tests. Sorption

A. T. Lukyanov; V. M. Inyushin; A. P. Gorokhov

1987-01-01

439

N+CPT clock resonance  

SciTech Connect

In a typical compact atomic time standard a current modulated semiconductor laser is used to create the optical fields that interrogate the atomic hyperfine transition. A pair of optical sidebands created by modulating the diode laser become the coherent population trapping (CPT) fields. At the same time, other pairs of optical sidebands may contribute to other multiphoton resonances, such as three-photon N-resonance [Phys. Rev. A 65, 043817 (2002)]. We analyze the resulting joint CPT and N-resonance (hereafter N+CPT) analytically and numerically. Analytically we solve a four-level quantum optics model for this joint resonance and perturbatively include the leading ac Stark effects from the five largest optical fields in the laser's modulation comb. Numerically we use a truncated Floquet solving routine that first symbolically develops the optical Bloch equations to a prescribed order of perturbation theory before evaluating. This numerical approach has, as input, the complete physical details of the first two excited-state manifolds of {sup 87}Rb. We test these theoretical approaches with experiments by characterizing the optimal clock operating regimes.

Crescimanno, M. [Department of Physics and Astronomy, Youngstown State University, Youngstown, Ohio 44555 (United States); Hohensee, M. [MS-59, Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, Massachusetts 02138 (United States)

2008-12-15

440

Nonconfocal multimode resonators for masers  

Microsoft Academic Search

The case of a resonator composed of two concave spherical reflectors separated by an arbitrary distance is examined. The general problem of the electromagnetic field distribution over the nonconfocal aperture is first formulated by means of the Huygens principle. The solution of the resulting integral equation is obtained analytically in the highly nonconfocal limit. It was found that when the

R. F. Soohoo

1963-01-01

441

Nonparaxial eigenmodes of stable resonators  

Microsoft Academic Search

A method to determine the nonparaxial eigenmodes of stable resonators is presented. The method is based on the perturbation theory of Lax et al. For calculating nonparaxial components of the electric field. A matrix formalism which uses a mode expansion into paraxial Hermite-Gaussian modes is applied to describe the nonparaxial propagation and the phase shift at a parabolic and a

Holger Laabs; Ari T. Friberg

1999-01-01

442

Spin Motion Near Snake Resonances  

NASA Astrophysics Data System (ADS)

We give a brief account of on-going work on the loss of polarisation during acceleration close to so-called snake resonances in proton storage rings. We show that within the model studied here the polarisation can be preserved if the rate of acceleration is low enough.

Barber, D. P.; Vogt, M.

2007-06-01

443

Airborne surface plasmon resonance biosensing  

Microsoft Academic Search

On March 14, 2003 an experimental aircraft fitted with surface plasmon resonance (SPR) biosensors connected to an air sampling system performed a 90-minute flight over Renton, Washington, demonstrating the first-ever use of SPR sensors for airborne biodetection. In this paper, we describe the instrumentation constructed for this purpose, the experiment conducted, and the results obtained. Instrumentation was based on Texas

Timothy M. Chinowsky; Alexei Naimushin; Scott Soelberg; Charles Spinelli; Peter Kauffman; Sinclair S. Yee; Clement E. Furlong

2004-01-01

444

INVESTIGATION OF RESONANT OPTOACOUSTIC CELLS  

EPA Science Inventory

A theory describing the optoacoustic signal is presented; dependence on both cell and gas parameters are given and the advantage of operating at a resonant frequency is discussed. Three elliptical cells with major axes 5.8, 12.7, and 15.2 cm (corresponding minor axes 5.5, 11.0; a...

445

Nucleon Resonances and Quark Structure  

NASA Astrophysics Data System (ADS)

A review of the past 50 years of study of resonances, leading to our understanding of the quark content of baryons and mesons. The quark structure of the proton as revealed through deep inelastic scattering. Structure functions and what they reveal about proton structure. Prospects for further studies with new and upgraded facilities, particularly a proposed electron-ion collider.

Londergan, J. T.

446

A tunable electromechanical Helmholtz resonator  

NASA Astrophysics Data System (ADS)

Acoustic liners are used in turbofan engine nacelles for the suppression of engine noise. For a given engine, there are different optimum impedance distributions associated with take-off, cut-back, and approach flight conditions. The impedance of conventional acoustic liners is fixed for a given geometry, and conventional active liner approaches are impractical. This project addresses the need for a tunable impedance through the development of an electromechanical Helmholtz resonator (EMHR). The device consists of a Helmholtz resonator with the standard rigid backplate replaced by a compliant piezoelectric composite. Analytical models (i.e., a lumped element model (LEM) and a transfer matrix (TM) representation of the EMHR) are developed to predict the acoustic behavior of the EMHR. The EMHR is experimentally investigated using the standard two-microphone method (TMM). The measurement results validate both the LEM and the TM of the EMHR. Good agreement between predicted and measured impedance is obtained. Short- and open-circuit loads define the limits of the tuning range using resistive and capacitive loads. There is approximately a 9% tuning limit under these conditions for the non-optimized resonator configuration studied. Inductive shunt loads result in a 3 degree-of-freedom (DOF) system and an enhanced tuning range of over 47% that is not restricted by the short- and open-circuit limits. Damping coefficient measurements for a piezoelectric backplate in a vacuum chamber are performed and indicate that the damping is dominated by structural damping losses. A Pareto optimization design based on models of the EMHR is performed with non-inductive loads. The EMHR with non-inductive loads has 2DOF and two resonant frequencies. The tuning ranges of the two resonant frequencies of the EMHR with non-inductive loads cannot be optimized simultaneously, so a trade-off (Pareto solution) must be reached. The Pareto solution shows how design trade-offs can be used to satisfy specific design requirements. The goal of the optimization of the EMHR with inductive loads is to achieve optimal tuning of the three resonant frequencies. The results indicate that it is possible to keep the acoustic reactance of the resonator nearly constant within a given frequency range.

Liu, Fei

447

An improved inductive coupler for suppressing a shift in the resonance frequency of electron paramagnetic resonance resonators  

Microsoft Academic Search

The development of in vivo electron paramagnetic resonance spectrometers has generated a need for a better method of inductive coupling between a microwave resonator and a transmission line. We describe here an approach, based on introducing an additional impedance transformer between a coupling loop and the transmission line. This additional transformer decreases (by a factor of 20) the resonance frequency

Hiroshi Hirata; Tadeusz Walczak; Harold M. Swartz

1997-01-01

448

Tentorial hemorrhage associated with vacuum extraction.  

PubMed

The clinical and radiologic descriptions of three neonates with tentorial hemorrhage after vacuum extraction are reported. All patients were full term, with Apgar scores of 8 or more; one patient experienced fetal distress during delivery. Within 36 hours after birth, the neonates had multiple generalized seizures; computed tomography or magnetic resonance imaging outlined distinctive tentorial hemorrhages with extension over the superior surface of the cerebellum or inferior surface of the occipital lobe. One patient had diffuse hypoxic-ischemic injury, and another had bilateral temporal lobe infarcts. Treatment included medical control of seizures and intracranial hypertension; one patient had surgical evacuation of bilateral subdural hematomas. Follow-up from 1 to 5 years showed significant developmental delays in two patients. These cases demonstrate that the forces generated on the fetal cranium by vacuum extraction are similar to those produced by forceps and result in tentorial laceration, venous rupture, and subdural hemorrhage. Because these hemorrhages may be associated with significant ischemic injury, serial radiologic evaluation is recommended for the detection of persistent structural abnormalities. PMID:2314967

Hanigan, W C; Morgan, A M; Stahlberg, L K; Hiller, J L

1990-04-01

449

Statistical-Based Approach for Extracting 3D Blood Vessels from TOF-MyRA Data  

Microsoft Academic Search

In this paper we present an automatic statistical intensity based- approach for extracting the 3D cerebrovascular system from time-of-flight (TOF) magnetic resonance angiography (MRA) data. The voxels of the dataset are classified as either background tissues, which are modeled by a finite mixture of one Rayleigh and two normal distributions, or blood vessels, which are modeled by one normal distribution.

M. Sabry Hassouna; Aly A. Farag; Stephen G. Hushek; Thomas Moriarty

2003-01-01

450

Automated 3-D Extraction of Inner and Outer Surfaces of Cerebral Cortex from MRI  

Microsoft Academic Search

Automatic computer processing of large multidimensional images such as those produced by magnetic resonance imaging (MRI) is greatly aided by deformable models, which are used to extract, identify, and quantify specific neuroanatomic structures. A general method of deforming polyhedra is presented here, with two novel features. First, explicit prevention of self-intersecting surface geometries is provided, unlike conventional deformable models, which

David MacDonald; Noor Kabani; David Avis; Alan C. Evans

2000-01-01

451

SAR Calculations in Human Head Model Extracted from Thermal Infrared Images  

Microsoft Academic Search

In electromagnetic dosimetry, anatomical human models are commonly obtained by segmentation of magnetic resonance imaging (MRI) or computed tomography (CT) scans. In this paper, a human head model extracted from thermal IR images is examined in terms of its applicability to specific absorption rate (SAR) calculations. Since thermal scans are two-dimensional (2-D) representation of surface temperature, this allows researchers to

Akram Gasmelseed; Jasmy Yunus

2010-01-01

452

Leptomeningeal cyst in newborns due to vaccum extraction: report of two cases  

Microsoft Academic Search

Two new cases of leptomeningeal cysts subsequent to vacuum extraction are reported. Both children presented with a huge, nonpulsating, transilluminating subgaleal collection over the anterior fontanel that appeared soon after instrument delivery. Plain X-rays, computed tomography, and magnetic resonance imaging confirmed that the subgaleal collection was cerebrospinal fluid and showed the presence of a diastatic coronal suture in both cases.

Vincent de Paul Djientcheu; Bénédict Rilliet; Jacqueline Delavelle; Maria Argyropoulo; François Gudinchet; Nicolas Tribolet

1996-01-01

453

Extraction of Brain Tumor from MR Images Using One-Class Support Vector Machine  

Microsoft Academic Search

A novel image segmentation approach by exploring one-class support vector machine (SVM) has been developed for the extraction of brain tumor from magnetic resonance (MR) images. Based on one-class SVM, the proposed method has the ability of learning the nonlinear distribution of the image data without prior knowledge, via the automatic procedure of SVM parameters training and an implicit learning

J. Zhou; K. L. Chan; V. F. H. Chong; S. M. Krishnan

2005-01-01

454

Localized ferromagnetic resonance using Magnetic Resonance Force Microscopy  

NASA Astrophysics Data System (ADS)

Magnetic Resonance Force Microscopy (MRFM) is a novel approach to scanned probe imaging, combining the advantages of Magnetic Resonance Imaging (MRI) with Scanning Probe Microscopy (SPM) [1]. It has extremely high sensitivity that has demonstrated detection of individual electron spins [2] and small numbers of nuclear spins [3]. Here we describe our MRFM experiments on Ferromagnetic thin film structures. Unlike ESR and NMR, Ferromagnetic Resonance (FMR) is defined not only by local probe field and the sample structures, but also by strong spin-spin dipole and exchange interactions in the sample. Thus, imaging and spatially localized study using FMR requires an entirely new approach. In MRFM, a probe magnet is used to detect the force response from the sample magnetization and it provides local magnetic field gradient that enables mapping of spatial location into resonance field. The probe field influences on the FMR modes in a sample, thus enabling local measurements of properties of ferromagnets. When sufficiently intense, the inhomogeneous probe field defines the region in which FMR modes are stable, thus producing localized modes. This feature enables FMRFM to be important tool for the local study of continuous ferromagnetic samples and structures. In our experiments, we explore the properties of the FMR signal as the strength of the local probe field evolves from the weak to strong perturbation limit. This underlies the important new capability of Ferromagnetic resonance imaging, a powerful new approach to imaging ferromagnet. The new developed FMR imaging technique enables FMR imaging and localized FMR spectroscopy to combine spectroscopy and lateral information of ferromagnetic resonance images [4][5]. Our theoretical approach agrees well with spatially localized spectroscopy and imaging results. This approach also allows analysis and reconstruction of FMR modes in a sample. Finally we consider the effect of strong probe fields on FMR modes. In this regime the probe field significantly modifies the FMR modes. In particular we observe the complete local suppression of the FMR mode under the probe. This provides as a new tool for local study of continuous ferromagnetic thin films and microstructures.

Kim, Jongjoo

455

Learning for Collective Information Extraction  

Microsoft Academic Search

An Information Extraction (IE) system analyses a set of documents with the aim of identifying certain types of entities and relations between them. Most IE systems treat separate potential extractions as independent. However, in many cases, considering influence s between different candidate extractions could improve overall accuracy. For example, phrase repetitions inside a document are usually associated with the same

Razvan C. Bunescu

2004-01-01

456

Automatic thesaurus extraction for Icelandic  

Microsoft Academic Search

Thesauri are becoming a common resource used in various Natural Language Processing and Information Retrieval related tasks. Methods for automatic extraction of thesauri have just recently begun performing well enough for practical use. A method to automatically extract a thesaurus for Icelandic from a tagged and parsed corpus was implemented and evaluated. The method is based on extracting relational trigrams

Frank Arthur; Blöndahl Cassata

457

Challenges in Managing Information Extraction  

ERIC Educational Resources Information Center

|This dissertation studies information extraction (IE), the problem of extracting structured information from unstructured data. Example IE tasks include extracting person names from news articles, product information from e-commerce Web pages, street addresses from emails, and names of emerging music bands from blogs. IE is all increasingly…

Shen, Warren H.

2009-01-01

458

Waveguide-mode resonance biosensor development  

Microsoft Academic Search

A new class of highly sensitive bio- and chemical sensors that utilizes a resonant waveguide grating is developed. This fibertip resonant sensor may be applicable to medical diagnostics, drug development, environmental monitoring, and homeland security.

D. Wawro; S. Tibuleac; R. Magnusson

2003-01-01

459

Parametric oscillations in a whispering gallery resonator.  

PubMed

We demonstrate strongly nondegenerate optical continuous-wave parametric oscillations in crystalline whispering gallery mode resonators fabricated from LiNbO3. The required phase matching is achieved by geometrical confinement of the modes in the resonator. PMID:17186049

Savchenkov, A A; Matsko, A B; Mohageg, M; Strekalov, D V; Maleki, L

2007-01-15

460

Resonance formation in photon-photon collisions  

SciTech Connect

Recent experimental progress on resonance formation in photon-photon collisions is reviewed with particular emphasis on the pseudoscalar and tensor nonents and on the ..gamma gamma..* production of spin-one resonances. 37 refs., 17 figs., 5 tabs.

Gidal, G.

1988-08-01

461

Optical phase conjugate resonators, bistabilities and applications  

Microsoft Academic Search

Recent work on phase conjugate resonators and their bistabilities and applications is reviewed. Emphasis is given to resonators involving degenerate four-wave mixing and those involving Brillouin enhanced four-wave mixing.

Putcha Venkateswarlu; Mostafa Dokhanian; P. C. Sekhar; M. C. George; H. Jagannath

1990-01-01

462

Azbel Kaner Resonance in Gaseous Plasmas.  

National Technical Information Service (NTIS)

The cyclotron resonances of ordinary electromagnetic fields in dense gaseous plasmas are analyzed. The phenomenon is similar to Azbel Kaner resonance in cryogenic metals. The collisionless absorption of electromagnetic fields by electrons and the propagat...

K. Minami

1972-01-01

463

Magnetic Resonance Spectroscopy in Biological Systems.  

National Technical Information Service (NTIS)

These notes give a general view of the various methods of magnetic resonance spectroscopy and of their possible applications to biological and medical problems. After analyzing the fundamental NMR and EPR techniques, double resonance (ENDOR), pulsed NMR a...

E. Tiezzi

1971-01-01

464

Application of ultrasound in extractive metallurgy: Sonochemical extraction of nickel  

NASA Astrophysics Data System (ADS)

The importance of ultrasound in solvent extraction was examined by studying solvent extraction of nickel with Lix 65N and Lix 70 extractants. The studied parameters were ultrasonic energy and frequency, pH, temperature, and organic and aqueous solution composition. The stability of extractants under the influence of ultrasound was also examined. It was found that ultrasound had a significant importance, because it increased the extraction rates four- to sevenfold. The effect of ultrasound was physical, i.e., to increase the surface area. Ultrasonic energy consumption was also evaluated. The consumption was high, but it can be significantly reduced by the appropriate method of application. A novel solvent extraction method, extraction-in-pipe, was also proposed.

Pesic, Batric; Zhou, Taili

1992-01-01

465

Aqueous extracts of cigarette tar containing the tar free radical cause DNA nicks in mammalian cells.  

PubMed Central

The ability of aqueous extracts of cigarette tar to nick DNA was investigated using viable mammalian cells. Tar extracts contain a radical with a stable electron spin resonance (ESR) signal at g = 2.0036 characteristic of a semiquinone. The association of the tar component that carries the ESR signal with DNA was demonstrated using viable rat alveolar macrophages. The formation of single-strand DNA breaks caused by cigarette tar extracts in viable rat thymocytes follows saturation kinetics, indicating a tar component associates with DNA and then nicks it. These studies support our hypothesis that tar components that contain the cigarette tar radical can enter cells, associate with, and then nick DNA.

Stone, K K; Bermudez, E; Pryor, W A

1994-01-01

466

Compact, narrow bandwidth, lumped element bandstop resonators  

Microsoft Academic Search

This letter describes the design and simulation of novel, highly compact, lumped element bandstop resonators. The resonators are fabricated using copper microstrip lines, with resonant frequencies around 5GHz but with areas of only 1.075mm × 1.275mm. Each resonator consists of 8 interdigital capacitive fingers in parallel with a straight line inductor. The new design offers at least a 40% size

Zaid Aboush; Adrian Porch

2005-01-01

467

Magnetic resonance of a single molecular spin  

Microsoft Academic Search

Magnetic-resonance spectroscopy on single molecules represents the ultimate limit in sensitivity of electron spin resonance: the detection of a single molecular spin. This is achieved by combining single molecule spectroscopy and optically detected magnetic resonance. Experimental results on pentacene in p-terphenyl both in zero-field and in the presence of a weak magnetic field demonstrate that magnetic-resonance spectroscopy on single molecules

Jürgen Köhler

1999-01-01

468

Collective resonance in pion-nucleus scattering  

Microsoft Academic Search

Pion-nucleus scattering is described by the excitation of bound nucleons into the ..delta.. resonance leading to isobaric resonances of the whole nucleus. A few broad collective resonances of different multipolarity are shown to dominate elastic and inelastic ..pi..-¹²C scattering. From the qualitatively good agreement with the data, we conclude that those giant isobaric resonances are a general feature of the

K. Klingenbeck; M. Dillig; M. G. Huber

1978-01-01

469

Stark resonances stemming from continuum thresholds  

SciTech Connect

In the Stark effect for the inverted {delta}-function potential, there are two kinds of field-induced resonances: the resonance stemming from the bound state supported by the bare potential, and a doubly infinite family of resonances originating from the continuum threshold. In this paper, we derive asymptotic expressions for the real and the imaginary parts (positions and halfwidths) of all these resonances as functions of the applied electric field, and then numerically track their behavior with changing field strength.

Alvarez, Gabriel; Sundaram, Bala [Departamento de Fisica Teorica II, Facultad de Ciencias Fisicas, Universidad Complutense, 28040 Madrid, (Spain); Graduate Faculty in Physics and Department of Mathematics, City University of New York, CSI, Staten Island, New York, 10314, USA (United States)

2003-07-01

470

Femtoscopy in hydrodynamics-inspired models with resonances  

SciTech Connect

Effects of the choice of the freeze-out hypersurface and resonance decays on the Hanbury-Brown-Twiss (HBT) interferometry in relativistic heavy-ion collisions are studied in detail within a class of models with single freeze-out. The Monte-Carlo method, as implemented in THERMINATOR, is used to generate hadronic events describing production of particles from a thermalized and expanding source. All well-established hadronic resonances are included in the analysis as their role is crucial at large freeze-out temperatures. We find that presence of the the short-lived resonances increase the pionic HBT radii by about 1 fm. We use the two-particle method to extract the correlation functions, which allows us to study the Coulomb effects. We find that the pion HBT data from the Relativistic Heavy Ion Collider are fully compatible with the single freeze-out scenario, pointing at the shape of the freeze-out hypersurface where the transverse radius is decreasing with time. Results for the single-particle spectra for this situation are also presented. Finally, we present predictions for the kaon femtoscopy.

Kisiel, Adam; Florkowski, Wojciech; Broniowski, Wojciech; Pluta, Jan [Faculty of Physics, Warsaw University of Technology, PL-00661 Warsaw (Poland) and SUBATECH, Laboratoire de Physique Subatomique et des Technologies Associees, EMN-IN2P3/CNRS-Universite, Nantes, F-44307 (France); Institute of Physics, SwiePtokrzyska Academy, ul. SwiePtokrzyska 15, PL-25406 Kielce (Poland) and H. Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Cracow (Poland); Faculty of Physics, Warsaw University of Technology, PL-00661 Warsaw (Poland)

2006-06-15

471

White-light whispering gallery mode resonators.  

PubMed

We propose theoretically and demonstrate experimentally white-light whispering gallery mode resonators. These resonators have essentially a continuous modal spectrum accompanied by ultrahigh-Q frequency-independent quality factors. Applications of the resonators for ringdown spectroscopy and light modulation are discussed. PMID:16419888

Savchenkov, Anatoliy A; Matsko, Andrey B; Maleki, Lute

2006-01-01

472

Isovector resonances in pion charge exchange  

SciTech Connect

The (..pi../sup + -/, ..pi../sup 0/) reactions as probes of isovector resonances are discussed. Experimental observation of the isovector monopole resonance is reported. Experimental results are presented for L = 0, 1, and 2 isovector resonances and are compared to random-phase approximation calculations.

Bowman, J.D.

1985-01-01

473

Optical giant resonances in nuclear reactions  

Microsoft Academic Search

Physical reasons for optical giant resonances being a very general ; feature of nuclear reactions are discussed. Optical giant resonances, so ; familiar in the scattering of nucleons on nuclei, were also observed in elastic ; cross sections of composite particles scattered by nuclei and in reaction ; channels of a compound nucleus decay. That this optical giant resonance ;

K. Wildermuth; R. L. Carovillano

1961-01-01

474

Bistable electron magnetic resonance in solids  

Microsoft Academic Search

This paper describes the phenomenon of Bistable Electron Magnetic Resonance, which manifests itself by a resonance line with a distorted shark fin-like shape. This effect requires only a fluctuating hyperfine interaction between electron spins and nuclear spins. It is demonstrated for shallow donors in semiconductors and conduction electrons in light metals. Bistability is an intrinsic property of electron magnetic resonance

Didier Gourier; Laurent Binet; Olivier Guillot-Noël

2004-01-01

475

Neutron Resonance Parameters for Mo92 (Molybdenum)  

Microsoft Academic Search

This document is part of the Supplement containing the complete sets of data of Volume 24 `Neutron Resonance Parameters' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms'. It provides the neutron resonance parameters for the isotope Mo-92 (Molybdenum). Also included are spectra of gamma-rays from neutron resonance capture.

S. I. Sukhoruchkin; Z. N. Soroko

2009-01-01

476

High temperature resonant ultrasound spectroscopy methods  

Microsoft Academic Search

Resonant ultrasound spectroscopy (RUS) is a technique to obtain the full elastic tensor of single crystal materials by measuring the mechanical resonances of a polished sample. Any direct resonance measurement at high temperatures is limited by the fact that most ultrasound transducers have an upper operational limit of 200-300C. High temperature RUS measurements are made possible by separating the sample,

Guangyan Li; Gary Lamberton; Josh Gladden

2008-01-01

477