Sample records for resonance nqr techniques

  1. Explosives detection by nuclear quadrupole resonance (NQR)

    NASA Astrophysics Data System (ADS)

    Garroway, Allen N.; Buess, Michael L.; Yesinowski, James P.; Miller, Joel B.; Krauss, Ronald A.

    1994-10-01

    Pure nuclear quadrupole resonance (NQR) of 14N nuclei is quite promising as a method for detecting explosives such as RDX and contraband narcotics such as cocaine and heroin in quantities of interest. Pure NQR is conducted without an external applied magnetic field, so potential concerns about damage to magnetically encoded data or exposure of personnel to large magnetic fields are not relevant. Because NQR frequencies of different compounds are quite distinct, we do not encounter false alarms from the NQR signals of other benign materials. We have constructed a laboratory prototype NQR explosives detector which interrogates a volume of 300 liters (10 ft3). This paper presents abbreviated results from a demonstration of the laboratory prototype NQR explosives detector conducted at the Federal Aviation Administration Technical Center in May 1994 on RDX-based explosives.

  2. Frequency selective detection of nuclear quadrupole resonance (NQR) spin echoes

    NASA Astrophysics Data System (ADS)

    Somasundaram, Samuel D.; Jakobsson, Andreas; Smith, John A. S.; Althoefer, Kaspar A.

    2006-05-01

    Nuclear Quadrupole Resonance (NQR) is a radio frequency (RF) technique that can be used to detect the presence of quadrupolar nuclei, such as the 14N nucleus prevalent in many explosives and narcotics. The technique has been hampered by low signal-to-noise ratios and is further aggravated by the presence of RF interference (RFI). To ensure accurate detection, proposed detectors should exploit the rich form of the NQR signal. Furthermore, the detectors should also be robust to any remaining residual interference, left after suitable RFI mitigation has been employed. In this paper, we propose a new NQR data model, particularly for the realistic case where multiple pulse sequences are used to generate trains of spin echoes. Furthermore, we refine two recently proposed approximative maximum likelihood (AML) detectors, enabling the algorithm to optimally exploit the data model of the entire echo train and also incorporate knowledge of the temperature dependent spin-echo decay time. The AML-based detectors ensure accurate detection and robustness against residual RFI, even when the temperature of the sample is not precisely known, by exploiting the dependencies of the NQR resonant lines on temperature. Further robustness against residual interference is gained as the proposed detector is frequency selective; exploiting only those regions of the spectrum where the NQR signal is expected. Extensive numerical evaluations based on both simulated and measured NQR data indicate that the proposed Frequency selective Echo Train AML (FETAML) detector offers a significant improvement as compared to other existing detectors.

  3. Methyl quantum tunneling and nitrogen-14 NQR NMR studies using a SQUID magnetic resonance spectrometer

    SciTech Connect

    Black, B.E. [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry]|[Lawrence Berkeley Lab., CA (United States)

    1993-07-01

    Nuclear Magnetic Resonance (NMR) and Nuclear Quadrupole Resonance (NQR) techniques have been very successful in obtaining molecular conformation and dynamics information. Unfortunately, standard NMR and NQR spectrometers are unable to adequately detect resonances below a few megahertz due to the frequency dependent sensitivity of their Faraday coil detectors. For this reason a new spectrometer with a dc SQUID (Superconducting Quantum Interference Device) detector, which has no such frequency dependence, has been developed. Previously, this spectrometer was used to observe {sup 11}B and {sup 27}Al NQR resonances. The scope of this study was increased to include {sup 23}Na, {sup 51}V, and {sup 55}Mn NQR transitions. Also, a technique was presented to observe {sup 14}N NQR resonances through cross relaxation of the nitrogen polarization to adjacent proton spins. When the proton Zeeman splitting matches one nitrogen quadrupoler transition the remaining two {sup 14}N transitions can be detected by sweeping a saturating rf field through resonance. Additionally, simultaneous excitation of two nitrogen resonances provides signal enhancement which helps to connect transitions from the same site. In this way, nitrogen-14 resonances were observed in several amino acids and polypeptides. This spectrometer has also been useful in the direct detection of methyl quantum tunneling splittings at 4.2 K. Tunneling, frequencies of a homologous series of carboxylic acids were measured and for solids with equivalent crystal structures, an exponential correlation between the tunneling frequency and the enthalpy of fusion is observed. This correlation provides information about the contribution of intermolecular interactions to the energy barrier for methyl rotation.

  4. New technologies: nuclear quadrupole resonance as an explosive and narcotic detection technique

    Microsoft Academic Search

    Vadim S Grechishkin; Nikolai Ya Sinyavskii

    1997-01-01

    Possibilities of detecting nuclear quadrupole resonance (NQR) signals in explosives and drugs are considered. Direct and indirect NQR techniques for searching substances are described and the potentialities of various experimental methods are compared.

  5. Pure Nuclear Quadrupole Resonance Techniques for Quantum Computation

    NASA Astrophysics Data System (ADS)

    Huang, Wei-Han; Chen, Zilong; Chuang, Isaac

    2003-03-01

    Pure nuclear quadrupole resonance (NQR) at zero magnetic field provides an accessible means for experimentation with the techniques of quantum computation. We present the design and implementation of a novel benchtop NQR apparatus utilizing modern communication electronics, and featuring a high efficiency, low cost class E amplifier with an integrated and tunable probe. Using this apparatus, we study the chlorine and nitrogen NQR resonances in para-dichlorobenzene and sodium nitrite, applying multiple pulse excitation sequences derived using methods of quantum circuits.

  6. INSTRUMENTS AND METHODS OF INVESTIGATION: New technologies: nuclear quadrupole resonance as an explosive and narcotic detection technique

    NASA Astrophysics Data System (ADS)

    Grechishkin, Vadim S.; Sinyavskii, Nikolai Ya

    1997-04-01

    Possibilities of detecting nuclear quadrupole resonance (NQR) signals in explosives and drugs are considered. Direct and indirect NQR techniques for searching substances are described and the potentialities of various experimental methods are compared.

  7. Measurement of in-situ stress in salt and rock using NQR techniques

    SciTech Connect

    Schempp, E.; Hirschfeld, T.; Klainer, S.

    1980-12-01

    A discussion of how stress and strain affect the quantities which can be measured in an NQR experiment shows that, for stresses of the magnitude to be expected at depths up to about 10,000 feet, quadrupole coupling constants will fall in the range of 1 to 10 kHz for both the sodium and chloride ions in NaCl. The most promising system involves pulsed nuclear double resonance detection; and alterative is to observe the quadrupolar splitting of the NMR signal. Choices to be made in the measurement and mapping techniques are discussed. The well-known perturbation of the homogenous stress field in the neighborhood of a borehole is shown to be advantageous from the point of view of obtaining directional information on the stress. Construction and operation of a borehole stress sensor are considered. The NQR technique seems feasible for measuring the magnitude and direction of underground stress with a resolution of about 25 psi, or 2.5% at 1000 psi. Downhole instrumentation suitable for in-situ determinations of stress appears within the state of the art. Additional tasks required on the project are identified.

  8. Nuclear quadrupole resonance detection of explosives: an overview

    NASA Astrophysics Data System (ADS)

    Miller, Joel B.

    2011-06-01

    Nuclear Quadrupole Resonance (NQR) is a spectroscopic technique closely related to Nuclear Magnetic Resonance (NMR) and Magnetic Resonance Imaging (MRI). These techniques, and NQR in particular, induce signals from the material being interrogated that are very specific to the chemical and physical structure of the material, but are relatively insensitive to the physical form of the material. NQR explosives detection exploits this specificity to detect explosive materials, in contrast to other well known techniques that are designed to detect explosive devices. The past two decades have seen a large research and development effort in NQR explosives detection in the United States aimed at transportation security and military applications. Here, I will briefly describe the physical basis for NQR before discussing NQR developments over the past decade, with particular emphasis on landmine detection and the use of NQR in combating IED's. Potential future directions for NQR research and development are discussed.

  9. Chlorine NQR on Derivatives of Chloral

    NASA Astrophysics Data System (ADS)

    Hashimoto, Masao; Weiden, Norbert; Weiss, Alarich

    1980-10-01

    The 35Cl-NQR spectrum of several derivatives of chloral, Cl3CCHO, was studied in the ranee 77 K ? T ? Tm. By use of the spin echo double resonance technique a relative assignment of the resonances to different Cl3C-groups within one crystallized compound was possible. The solid compounds studied are: High temperature phase of chloral hydrate, Cl3CCH(OH)2; parachloral, (Cl3CCHO)3, (?-and ß-isomer); the two phases of chloral hemihydrate Cl3CCHO · 1/2 H2O; chloralide (II); chloralhemithiohydrate, Cl3CCHO · 1/2 H2S. The structure of the molecules in the solid state and the fade out of the NQR resonances are discussed.

  10. NQR: From imaging to explosives and drugs detection

    NASA Astrophysics Data System (ADS)

    Osán, Tristán M.; Cerioni, Lucas M. C.; Forguez, José; Ollé, Juan M.; Pusiol, Daniel J.

    2007-02-01

    The main aim of this work is to present an overview of the nuclear quadrupole resonance (NQR) spectroscopy capabilities for solid state imaging and detection of illegal substances, such as explosives and drugs. We briefly discuss the evolution of different NQR imaging techniques, in particular those involving spatial encoding which permit conservation of spectroscopic information. It has been shown that plastic explosives and other forbidden substances cannot be easily detected by means of conventional inspection techniques, such as those based on conventional X-ray technology. For this kind of applications, the experimental results show that the information inferred from NQR spectroscopy provides excellent means to perform volumetric and surface detection of dangerous explosive and drug compounds.

  11. Quadrupole Coupling Parameters and Structural Aspects of Crystalline and Amorphous Solids by NMR and Nqr.

    NASA Astrophysics Data System (ADS)

    Mao, Degen

    Nuclear quadrupole interaction is very sensitive to the local electron distribution and chemical bondings. NMR and NQR techniques have been combined to obtain the quadrupole coupling constant ({Qcc}) and asymmetry parameter (eta) and extract structural information for several borate, gallate, and metavanadate compounds and glasses. ^{71}Ga and ^{69}Ga NMR has been used to study crystalline beta-Ga _2O_3 and several gallate glasses. Quadrupole parameters were acquired for GaO_6 and GaO_4 units in beta-Ga_2 O_3 by the computer simulation of the NMR powder patterns. A sensitive CW NQR spectrometer was built to detect NQR resonances below 2 MHz. The spectrometer includes a modified Robinson oscillator-detector, a new bi-symmetric square wave Zeeman modulator and a computerized data acquisition system. ^{51}V (I = 7/2) NQR resonances below 850 kHz have been detected for several metavanadates at both room temperature and liquid nitrogen temperature. Quadrupole parameters thus obtained are an order of magnitude more accurate than values obtained by previous NMR studies. For a spin 3/2 nucleus, the pure NQR frequency {Q_{cc}over 2}sqrt{1+{eta^2over 3}}is insufficient to determine either Q_{cc} or eta. However, two methods, Zeeman perturbed NQR powder pattern and ^{10}B NQR, can be employed to obtain both Q_{cc } and eta. An example is given for ^{11}B in CaO-B_2O_3. With a double coil tank circuit design, pure ^ {11}B NQR was used to determine the fraction of borons in BO_3 and BO _4 configurations in hydrated zinc borates. ^{11}B NMR and NQR were also used to study lead borate glasses. Small changes in Q_{cc} (less than 2%) and eta (less than 0.1) suggest that BO_3 units with non-bridging oxygens are not present in the lead borate glasses.

  12. Polarization enhancement technique for nuclear quadrupole resonance detection.

    PubMed

    Kim, Y J; Karaulanov, T; Matlashov, A N; Newman, S; Urbaitis, A; Volegov, P; Yoder, J; Espy, M A

    2014-01-01

    We demonstrate a dramatic increase in the signal-to-noise ratio (SNR) of a nuclear quadrupole resonance (NQR) signal by using a polarization enhancement technique. By first applying a static magnetic field to pre-polarize one spin subsystem of a material, and then allowing that net polarization to be transferred to the quadrupole subsystem, we increased the SNR of a sample of ammonium nitrate by one-order of magnitude. PMID:24882748

  13. Fourier transform zero field NMR and NQR

    SciTech Connect

    Zax, D.B.

    1985-01-01

    In many systems the chemical shifts measured by traditional high resolution solid state NMR methods are insufficiently sensitive, or the information contained in the dipole-dipole couplings is more important. In these cases, Fourier transform zero field magnetic resonance may make an important contribution. Zero field NMR and NQR is the subject of this thesis. Chapter I presents the quantum mechanical background and notational formalism for what follows. Chapter II gives a brief review of high resolution magnetic resonance methods, with particular emphasis on techniques applicable to dipole-dipole and quadrupolar couplings. Level crossings between spin-1/2 and quadrupolar spins during demagnetization transfer polarization from high to low lambda nuclei. This is the basis of very high sensitivity zero field NQR measurements by field cycling. Chapter III provides a formal presentation of the high resolution Fourier transform zero field NMR method. Theoretical signal functions are calculated for common spin systems, and examples of typical spectra are presented. Chapters IV and V review the experimental progress in zero field NMR of dipole-dipole coupled spin-1/2 nuclei and for quadrupolar spin systems. Variations of the simple experiment describe in earlier chapters that use pulsed dc fields are presented in Chapter VI.

  14. Detection of {sup 14}N and {sup 35}Cl in cocaine base and hydrochloride using NQR, NMR, and SQUID techniques

    SciTech Connect

    Yesinowski, J.P.; Buess, M.L.; Garroway, A.N. [Naval Research Lab., Washington, DC (United States); Ziegeweid, M.; Pines, A. [Univ. of California, Berkeley, CA (United States)]|[Lawrence Berkeley Lab., CA (United States)

    1995-07-01

    Results from {sup 14}N pure NQR of cocaine in the free base form (cocaine base) yield a nuclear quadrupole coupling constant (NQCC) e{sup 2}Qq/h of 5.0229 ({+-}0.0001) MHz and an asymmetry parameter {eta} of 0.0395 ({+-}0.0001) at 295 K, with corresponding values of 5.0460 ({+-}0.0013) MHz and 0.0353 ({+-}0.0008) at 77 K. Both pure NQR (at 295-77 K) and a superconducting quantum interference device (SQUID) detector (at 4.2 K) were used to measure the very low (<1 MHz) {sup 14}N transition frequencies in cocaine hydrochloride; at 295 K the NQCC is 1.1780 ({+-}0.0014) MHz and the asymmetry parameter is 0.2632 ({+-}0.0034). Stepping the carrier frequency enables one to obtain a powder pattern without the severe intensity distortions that otherwise arise from finite pulse power. A powder pattern simulation using an NQCC value of 5.027 MHz and an asymmetry parameter {eta} of 0.2 agrees reasonably well with the experimental stepped-frequency spectrum. The use of pure NQR for providing nondestructive, quantitative, and highly specific detection of crystalline compounds is discussed, as are experimental strategies. 31 refs., 8 figs., 1 tab.

  15. 14 N NQR spectrum of sildenafil citrate

    NASA Astrophysics Data System (ADS)

    Stephenson, David; Singh, Nadia

    2015-04-01

    The 14N nuclear quadrupole resonance (NQR) spectrum of sildenafil citrate tablets has been recorded allowing the quadrupole coupling constants and asymmetry parameters of all six unique nitrogen atoms in its structure to be determined. A density function calculation gives results that are largely in agreement with the experimental values.

  16. Exploiting Spin Echo Decay in the Detection of Nuclear Quadrupole Resonance Signals

    Microsoft Academic Search

    Samuel D. Somasundaram; Andreas Jakobsson; John A. S. Smith; Kaspar Althoefer

    2007-01-01

    Nuclear quadrupole resonance (NQR) is a radio-frequency technique that can be used to detect the presence of quadrupolar nuclei, such as the 14N nucleus prevalent in many explosives and narcotics. In a typical application, one observes trains of decaying NQR echoes, in which the decay is governed by the spin echo decay time(s) of the resonant line(s). In most detection

  17. Fourier transform zero field NMR and NQR

    SciTech Connect

    Zax, D.B.

    1984-09-01

    The characterization of the structural and chemical properties of matter, particularly in disordered condensed phases, is a difficult process. Few analytical methods work effectively on polycrystalline or amorphous solids. In many systems the chemical shifts measured by traditional high resolution solid state NMR methods are insufficiently sensitive or the information contained in the dipole-dipole couplings is more important. In these cases Fourier transform zero field magnetic resonance may make an important contribution. Zero field NMR and NQR is the subjecti of this thesis.

  18. Optimal filtering in multipulse sequences for nuclear quadrupole resonance detection

    NASA Astrophysics Data System (ADS)

    Osokin, D. Ya.; Khusnutdinov, R. R.; Mozzhukhin, G. V.; Rameev, B. Z.

    2014-05-01

    The application of the multipulse sequences in nuclear quadrupole resonance (NQR) detection of explosive and narcotic substances has been studied. Various approaches to increase the signal to noise ratio (SNR) of signal detection are considered. We discussed two modifications of the phase-alternated multiple-pulse sequence (PAMS): the 180° pulse sequence with a preparatory pulse and the 90° pulse sequence. The advantages of optimal filtering to detect NQR in the case of the coherent steady-state precession have been analyzed. It has been shown that this technique is effective in filtering high-frequency and low-frequency noise and increasing the reliability of NQR detection. Our analysis also shows the PAMS with 180° pulses is more effective than PSL sequence from point of view of the application of optimal filtering procedure to the steady-state NQR signal.

  19. The incommensurate phase of 4,4'-dichlorobiphenyl sulphone reinvestigated by 35Cl NQR

    Microsoft Academic Search

    J. Schneider; A. Wolfenson; A. Brunetti

    1994-01-01

    In order to acquire new information about the normal-incommensurate (IC) phase transition and to check the existence of a lock-in transition in 4,4'-dichlorobiphenyl sulphone (4,4'-DCBS), a comprehensive 35Cl nuclear quadrupole resonance (NQR) study is reported. Detailed NQR measurements of frequency, line width and spin relaxation time (Tl) were obtained in the temperature range 80-270 K. The results show that the

  20. Zero-field NMR and NQR spectrometer

    SciTech Connect

    Bielecki, A.; Zax, D.B.; Zilm, K.W.; Pines, A.

    1986-03-01

    In comparison to high-field NMR, zero-field techniques offer advantages in terms of spectral interpretability in studies of polycrystalline or amorphous solids. This article describes a technique and apparatus for time-domain measurements of nuclear magnetism in the absence of applied fields (Fourier transform zero-field NMR and NQR). Magnetic field cycling and high field detection are employed to enhance sensitivity. The field cycling is accomplished with an air-driven shuttle system which moves the sample between regions of high and low magnetic field, in combination with switchable electromagnets in the low-field region. Sudden field steps or pulses are used to initiate coherent nuclear spin evolution in zero field and to monitor such evolution as a function of time. Experimental results are shown and analyzed. Possible variations on the basic method are described and their relative advantages are discussed.

  1. Landmine detection with nuclear quadrupole resonance

    Microsoft Academic Search

    Yingyi Tan; Stacy L. Tantum; Leslie M. Collins

    2002-01-01

    Nuclear quadrupole resonance (NQR) technology for the detection of explosives is of crucial importance in an increasing number of applications. For landmine detection, NQR has proven to be highly effective if the NQR sensor is not exposed to radio frequency interference (RFI). Since strong nonstationary RFI in the field is unavoidable, a robust detection method is required. With the aid

  2. NQR DETECTION OF SODIUM NITRITE RECRYSTALLIZED IN WOOD Jrmy Jover(1), (3)

    E-print Network

    Paris-Sud XI, Université de

    often used as a model in Nitrogen- 14 Quadrupole Resonance, namely sodium nitrite NaNO2. It hasNQR DETECTION OF SODIUM NITRITE RECRYSTALLIZED IN WOOD Jérémy Jover(1), (3) , Sarra Aissani(1 sample tubes have been impregnated by an aqueous solution of sodium nitrite (NaNO2). They were

  3. Acoustic resonance techniques for quality control

    SciTech Connect

    Sinha, D.N.

    1992-01-01

    Acoustic resonance based nondestructive techniques are described that can be used for both process and quality control in manufacturing. The Acoustic Resonance Spectroscopy (AS) technique is highlighted for its capability in fluid property (flow, density, viscosity, and speed of sound) monitoring. Possible applications of these noninvasive techniques for textile manufacturing are pointed out.

  4. Acoustic resonance techniques for quality control

    SciTech Connect

    Sinha, D.N.

    1992-09-01

    Acoustic resonance based nondestructive techniques are described that can be used for both process and quality control in manufacturing. The Acoustic Resonance Spectroscopy (AS) technique is highlighted for its capability in fluid property (flow, density, viscosity, and speed of sound) monitoring. Possible applications of these noninvasive techniques for textile manufacturing are pointed out.

  5. Acoustic resonance techniques for quality control

    NASA Astrophysics Data System (ADS)

    Sinha, D. N.

    Acoustic resonance based nondestructive techniques are described that can be used for both process and quality control in manufacturing. The Acoustic Resonance Spectroscopy (AS) technique is highlighted for its capability in fluid property (flow, density, viscosity, and speed of sound) monitoring. Possible applications of these noninvasive techniques for textile manufacturing are pointed out.

  6. 14N NQR in the tetrazole family

    NASA Astrophysics Data System (ADS)

    Pirnat, Janez; Lužnik, Janko; Jazbinšek, Vojko; Žagar, Veselko; Seliger, Janez; Klapötke, Thomas M.; Trontelj, Zvonko

    2009-10-01

    14N NQR frequencies and spin-lattice relaxation times were measured in technologically important 5-aminotetrazole and 5-aminotetrazole monohydrate at different temperatures between 77 K and 300 K. Five NQR triplets ?+, ?- and ?0 were found for the five inequivalent nitrogen atoms in each compound between 0.7 MHz and 4 MHz. Carr-Purcell based multipulse sequences were used to accumulate quadrupole echo signals before the FFT analysis. Assignment of the frequencies to atomic positions was made and the results are analysed in relation to the molecular chemical bonds and possible H-bonds in the crystal structures. The new NQR frequencies are reasonably related to the previously published NQR spectrum of the third family member, 1H-tetrazole.

  7. Zero field NMR and NQR with selective pulses and indirect detection

    SciTech Connect

    Millar, J.M.; Thayer, A.M.; Bielecki, A.; Zax, D.B.; Pines, A.

    1985-08-01

    Zero field NMR and NQR spectra are obtained by the application of dc magnetic field pulses to a demagnetized sample. Pulsed dc fields allow for selective excitation of isotopic species and provide a means for coherent manipulation of the spin system in zero field. Using these selective pulses and level crossing techniques, indirect detection of a quadrupolar nucleus may be accomplished via protons without obtaining the proton background signal in the NQR spectrum. Experimental results from a variety of /sup 1/H, /sup 2/H, and /sup 14/N homo- and heteronuclear systems are presented as an illustration of these techniques.

  8. Breast Magnetic Resonance Imaging Techniques

    Microsoft Academic Search

    Nola M. Hylton

    Magnetic resonance imaging (MRI) of the breast is finding wider clinical application as an adjunct diagnostic procedure to mammography and ultrasound. Because of its high sensitivity and effectiveness in dense breast tissue, MRI can be a valuable addition to the diagnostic work up of a patient with a breast abnormality or biopsy-proven cancer. The major limitation of breast MRI is

  9. A miniaturized NQR spectrometer for a multi-channel NQR-based detection device

    NASA Astrophysics Data System (ADS)

    Beguš, Samo; Jazbinšek, Vojko; Pirnat, Janez; Trontelj, Zvonko

    2014-10-01

    A low frequency (0.5-5 MHz) battery operated sensitive pulsed NQR spectrometer with a transmitter power up to 5 W and a total mass of about 3 kg aimed at detecting 14N NQR signals, predominantly of illicit materials, was designed and assembled. This spectrometer uses a standard software defined radio (SDR) platform for the data acquisition unit. Signal processing is done with the LabView Virtual instrument on a personal computer. We successfully tested the spectrometer by measuring 14N NQR signals from aminotetrazole monohydrate (ATMH), potassium nitrate (PN), paracetamol (PCM) and trinitrotoluene (TNT). Such a spectrometer is a feasible component of a portable single or multichannel 14N NQR based detection device.

  10. Anomalous H/D isotope effect on 35Cl NQR frequencies in piperidinium p-chlorobenzoate

    NASA Astrophysics Data System (ADS)

    Nakano, Ryo; Honda, Hisashi; Kimura, Taiki; Nakata, Eiichi; Takamizawa, Satoshi; Noro, Sumiko; Ishimaru, Shin'ichi

    2008-01-01

    Anomalous isotope effects were detected in the 35Cl nuclear quadrupole resonance (NQR) frequency of piperidinium p-chlrobenzoate (C5H10NH· ClC6H4COOH) by deuteration of hydrogen atoms. The atoms were determined to form two kinds of N H···O type H-bonds in the crystal structure. Large frequency shifts of the 35Cl resonance lines reaching 288 kHz at 77 K and 278 kHz at room temperature were caused upon deuteration, in spite of the fact that the Cl atoms in the molecule do not form hydrogen bonds in the crystal. Results of single crystal X-ray diffraction measurements and density-functional-theorem calculations suggest that a dihedral-angle change of 1.8° between benzene and the piperidine ring contributes to 35Cl NQR anomalous frequency shifts.

  11. ą?N nuclear quadrupole resonance study of polymorphism in famotidine.

    PubMed

    Lu?nik, Janko; Pirnat, Janez; Jazbinšek, Vojko; Lavri?, Zoran; Žagar, Veselko; Sr?i?, Stane; Seliger, Janez; Trontelj, Zvonko

    2014-09-01

    (14)N nuclear quadrupole resonance (NQR) in two known polymorphs of famotidine was measured. At room temperature, seven quadrupolar sets of transition frequencies (?(+), ?(-), and ?(0)) corresponding to seven different nitrogen sites in the crystal structure of each of the two polymorphs were found. This confirms the expected ability of NQR to distinguish polymorph B from its analog A. NQR can also measure their ratio in a solid mixture and in the final dosage form, that is, a tablet. The NQR frequencies, line shapes, and tentative assignation to all seven molecular (14)N atoms were obtained. Unravelment of these two entangled NQR spectra presents a valuable contribution to the NQR database and enables studies of some possible correlations therein. Moreover, nondestructive (14)N NQR studies of commercial famotidine tablets can reveal some details of the drug fabrication process connected with compression. PMID:24668530

  12. A General Numerical Analysis of Time-Domain NQR Experiments

    SciTech Connect

    Harel, Elad; Cho, Herman M.

    2006-12-01

    We introduce a general numerical approach for solving the Liouville equation of a quadrupolar nuclide that we show can be used to analyze time-domain NQR experiments. A computer-based treatment is necessitated by the dimensionality of the Liouville space, which precludes analytical, closed form solutions for I > 3/2. Accurate simulations of experimental nutation curves, forbidden transition intensities, powder and single crystal spectra, and off-resonance irradiation dynamics can be computed with this method. We also examine the validity of perturbative approximations where the signal intensity of a transition is proportional to the transition moment between the eigenstates of the system, thus providing a simple basis for determining selection rules. Our method allows us to calculate spectra for all values of the asymmetry parameter, ?, and sample orientations relative to the coil axis. We conclude by demonstrating the methodology for calculating the response of the quadrupole system to amplitude- and frequency-modulated pulses.

  13. Resonant optothermoacoustic detection: technique for measuring weak

    E-print Network

    on the effects that absorbed radiation induces in media. Probably the most widely used technique of this kind the use of a pyroelectric material to detect temperature variations induced by the absorbed radiation and micro-objects via linked thermal effects and by using a sharp mechanical resonance in a quartz crystal

  14. Measurement of temperature and temperature gradient in millimeter samples by chlorine NQR

    NASA Astrophysics Data System (ADS)

    Lužnik, Janko; Pirnat, Janez; Trontelj, Zvonko

    2009-09-01

    A mini-thermometer based on the 35Cl nuclear quadrupole resonance (NQR) frequency temperature dependence in the chlorates KClO3 and NaClO3 was built and successfully tested by measuring temperature and temperature gradient at 77 K and higher in about 100 mm3 active volume of a mini Joule-Thomson refrigerator. In the design of the tank-circuit coil, an array of small coils connected in series enabled us (a) to achieve a suitable ratio of inductance to capacity in the NQR spectrometer input tank circuit, (b) to use a single crystal of KClO3 or NaClO3 (of 1-2 mm3 size) in one coil as a mini-thermometer with a resolution of 0.03 K and (c) to construct a system for measuring temperature gradients when the spatial coordinates of each chlorate single crystal within an individual coil are known.

  15. 93Nb- and 27Al-NMR/NQR studies of the praseodymium based PrNb2Al20

    NASA Astrophysics Data System (ADS)

    Kubo, Tetsuro; Kotegawa, Hisashi; Tou, Hideki; Higashinaka, Ryuji; Nakama, Akihiro; Aoki, Yuji; Sato, Hideyuki

    2015-03-01

    We report a study of 93Nb- and 27Al-nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) in a praseodymium based compound PrNb2Al20. The observed NMR line at around 3 T and 30 K shows a superposition of typical powder patterns of one Nb signal and at least two Al signals. 93Nb-NMR line could be reproduced by using the previously reported NQR frequency ?Q ? 1.8MHz and asymmetry parameter ? ? 0 [Kubo T et al 2014 JPS Conf. Proc. 3 012031]. From 27Al-NMR/NQR, NQR parameters are obtained to be ?Q,A ? 1.53 MHz, and ?A ? 0.20 for the site A, and ?Q,B ? 2.28 MHz, and ?B ? 0.17 for the site B. By comparing this result with the previous 27Al-NMR study of PrT2Al20 (T = Ti, V) [Tokunaga Y et al 2013 Phys. Rev. B 88 085124], these two Al site are assigned to the two of three crystallographycally inequivalent Al sites.

  16. Electron density distribution in cladribine (2-chloro-2?-deoxyadenosine) - A drug against leukemia and multiple sclerosis - Studied by multinuclear NQR spectroscopy and DFT calculations

    NASA Astrophysics Data System (ADS)

    Latosi?ska, J. N.; Latosi?ska, M.; Seliger, J.; Žagar, V.; Kazimierczuk, Z.

    2009-07-01

    2-Chloro-2'-deoxyadenosine (Cladribine) chemotherapeutic drug has been studied experimentally in solid state by 35Cl NQR and NMR-NQR double resonance and theoretically by the Density Functional Theory. Fifteen resonance frequencies on 14N have been detected and assigned to particular nitrogen sites in the 2-CdA molecule. The effects of tautomerism, regioisomerism, conformations and molecular aggregations, related to intermolecular hydrogen bond formation, on the NQR parameters have been analysed within the DFT and AIM ( Atoms in Molecules) formalism. The properties of the whole molecule, the so-called global reactivity descriptors, have been calculated for a comparison of both syn and anti conformations of 2-CdA molecule to check the effect of crystal packing on molecular conformation.

  17. NQR Line Broadening Due to Crystal Lattice Imperfections and Its Relationship to Shock Sensitivity

    NASA Astrophysics Data System (ADS)

    Caulder, S. M.; Buess, M. L.; Garroway, A. N.; Miller, P. J.

    2004-07-01

    The hydrodynamic hot spot model is used to explain the difference between shock sensitive and shock insensitive explosives. Among the major factors that influence the shock sensitivity of energetic compounds are the quality and particle size of the energetic crystals used to formulate the cast plastic bonded explosive. As do all energetic compounds, RDX and HMX exhibit internal crystal defects the magnitude and type of which depend on the manufacturing process used to synthesize and re-crystallize the energetic compound. Nuclear Quadrupole Resonance (NQR) spectroscopy was used to determine the crystal quality of RDX, HMX and CL-20 obtained from various manufacturers. The NQR experimental results are discussed. Cast plastic bonded explosives were made using the RDX and HMX obtained from the various manufacturers and subsequently subjected to the NOL large-scale gap test (LSGT). The results of the LSGT are discussed and correlated with the NQR results. A relationship between the crystal defect density and shock initiation pressure of the plastic bonded explosive is developed and discussed.

  18. Crystallization and preliminary analysis of the NqrA and NqrC subunits of the Na+-translocating NADH:ubiquinone oxidoreductase from Vibrio cholerae.

    PubMed

    Vohl, Georg; Nedielkov, Ruslan; Claussen, Björn; Casutt, Marco S; Vorburger, Thomas; Diederichs, Kay; Möller, Heiko M; Steuber, Julia; Fritz, Günter

    2014-07-01

    The Na+-translocating NADH:ubiquinone oxidoreductase (Na+-NQR) from Vibrio cholerae is a membrane protein complex consisting of six different subunits NqrA-NqrF. The major domains of the NqrA and NqrC subunits were heterologously expressed in Escherichia coli and crystallized. The structure of NqrA1-377 was solved in space groups C222? and P2? by SAD phasing and molecular replacement at 1.9 and 2.1?Ĺ resolution, respectively. NqrC devoid of the transmembrane helix was co-expressed with ApbE to insert the flavin mononucleotide group covalently attached to Thr225. The structure was determined by molecular replacement using apo-NqrC of Parabacteroides distasonis as search model at 1.8?Ĺ resolution. PMID:25005105

  19. Review: Magnetic resonance imaging techniques in ophthalmology

    PubMed Central

    Fagan, Andrew J.

    2012-01-01

    Imaging the eye with magnetic resonance imaging (MRI) has proved difficult due to the eye’s propensity to move involuntarily over typical imaging timescales, obscuring the fine structure in the eye due to the resulting motion artifacts. However, advances in MRI technology help to mitigate such drawbacks, enabling the acquisition of high spatiotemporal resolution images with a variety of contrast mechanisms. This review aims to classify the MRI techniques used to date in clinical and preclinical ophthalmologic studies, describing the qualitative and quantitative information that may be extracted and how this may inform on ocular pathophysiology. PMID:23112569

  20. Electronic structure and biological activity of chosen DDT-type insecticides studied by 35Cl-NQR.

    PubMed

    Jadzyn, Maciej; Nogaj, Boles?aw

    2009-02-01

    A correlation between the electronic structure and biological activity of chosen dichlorodiphenyltrichloroethane (DDT)-type insecticides: 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane, 1,1-dichloro-2,2-bis(4-chlorophenyl)ethane, 2,2-bis(p-chlorophenyl)-1,1-dichloroethylene, 2,2-bis(4-chlorophenyl)ethanoic acid and 4,4'-dichlorobenzophenone (used in agriculture) has been analysed on the basis of the (35)Cl-nuclear quadrupole resonance (NQR) spectroscopy. The (35)Cl-NQR resonance frequencies measured at 77 K have been correlated with the lethal dose (LD(50)) parameter that characterises the biological activity of these insecticides. PMID:18942076

  1. A Technique for Adjusting Eigenfrequencies of WGM Resonators

    NASA Technical Reports Server (NTRS)

    Strekalov, Dmitry; Savchenkov, Anatoliy; Maleki, Lute; Matsko, Andrey; Iltchenko, Vladimir; Martin, Jan

    2009-01-01

    A simple technique has been devised for making small, permanent changes in the eigenfrequencies (resonance frequencies) of whispering-gallery-mode (WGM) dielectric optical resonators that have high values of the resonance quality factor (Q). The essence of the technique is to coat the resonator with a thin layer of a transparent polymer having an index of refraction close to that of the resonator material. Successive small frequency adjustments can be made by applying successive coats. The technique was demonstrated on a calcium fluoride resonator to which successive coats of a polymer were applied by use of a hand-made wooden brush. To prevent temperature- related frequency shifts that could interfere with the verification of the effectiveness of this technique, the temperature of the resonator was stabilized by means of a three-stage thermoelectric cooler. Measurements of the resonator spectrum showed the frequency shifts caused by the successive coating layers.

  2. NQR experiments on Sc-Y alloys at very low temperatures. [Absolute thermometry below 500[mu]K

    SciTech Connect

    Pollack, L.; Smith, E.N.; Richardson, R.C. (Cornell Univ., Ithaca, NY (United States))

    1992-10-01

    The authors performed Nuclear Quadrupole Resonance (NQR) experiments on an alloy of scandium and yttrium. They find that the characteristic resonance frequencies in zero external field are 50% larger than in pure scandium. This increase in frequency makes the Sc-Y alloy a better candidate for absolute thermometry below 500 [mu]K. However, the spin-lattice relaxation time of this alloy is more than an order of magnitude longer than in the pure scandium. In addition, an abrupt increase in the Korringa constant was observed for temperatures below 5mK.

  3. Chemical phase separation in carbon doped YBa 2Cu 3O 6+ x: a 63,65Cu NQR study

    NASA Astrophysics Data System (ADS)

    Grévin, B.; Berthier, Y.; Monot, I.; Wang, J.; Weiss, F.

    1997-02-01

    We report on 63,65Cu NQR spectra and nuclear spin-lattice relaxation rate (1/ T1) measurements at 4.2 K in YBa 2Cu 3O 6+ x powder samples with carbon concentrations ranging from 500 to 3000 ppm. A new NQR line appears at 30.90 MHz ( 63Cu line), the intensity of which is strongly correlated with the amount of carbon in the sample. The measurement of the spin-lattice relaxation rate for Cu corresponding to the different lines measured shows different relaxation behaviors. Furthermore a drastic change is observed for T1 between the two samples. We discuss the implications of these findings in the framework of chemical phase separation and compare to previous carbon retention studies in YBa 2Cu 3O 6+ x by other techniques.

  4. Analysis and calibration techniques for superconducting resonators.

    PubMed

    Cataldo, Giuseppe; Wollack, Edward J; Barrentine, Emily M; Brown, Ari D; Moseley, S Harvey; U-Yen, Kongpop

    2015-01-01

    A method is proposed and experimentally explored for in-situ calibration of complex transmission data for superconducting microwave resonators. This cryogenic calibration method accounts for the instrumental transmission response between the vector network analyzer reference plane and the device calibration plane. Once calibrated, the observed resonator response is analyzed in detail by two approaches. The first, a phenomenological model based on physically realizable rational functions, enables the extraction of multiple resonance frequencies and widths for coupled resonators without explicit specification of the circuit network. In the second, an ABCD-matrix representation for the distributed transmission line circuit is used to model the observed response from the characteristic impedance and propagation constant. When used in conjunction with electromagnetic simulations, the kinetic inductance fraction can be determined with this method with an accuracy of 2%. Datasets for superconducting microstrip and coplanar-waveguide resonator devices were investigated and a recovery within 1% of the observed complex transmission amplitude was achieved with both analysis approaches. The experimental configuration used in microwave characterization of the devices and self-consistent constraints for the electromagnetic constitutive relations for parameter extraction are also presented. PMID:25638068

  5. Anomalous HID isotope effect on 35Cl NQR frequencies in piperidinium p-chlorobenzoate

    NASA Astrophysics Data System (ADS)

    Nakano, Ryo; Honda, Hisashi; Kimura, Taiki; Nakata, Eiichi; Takamizawa, Satoshi; Noro, Sumiko; Ishimaru, Shin'ichi

    Anomalous isotope effects were detected in the 35CI nuclear quadrupole resonance (NQR) frequency of piperidinium p-chlrobenzoate (C5H10NH· CIC6H4COOH) by deuteration of hydrogen atoms. The atoms were determined to form two kinds of N-H...O type H-bonds in the crystal structure. Large frequency shifts of the 35CI resonance lines reaching 288 kHz at 77 K and 278 kHz at room temperature were caused upon deuteration, in spite of the fact that the CI atoms in the molecule do not form hydrogen bonds in the crystal. Results of single crystal X-ray diffraction measurements and density-functional-theorem calculations suggest that a dihedral-angle change of 1.8° between benzene and the piperidine ring contributes to 35CINQR anomalous frequency shifts.

  6. Fine frequency selection techniques for aluminum nitride Lamb wave resonators

    Microsoft Academic Search

    Ting-Ta Yen; Chih-Ming Lin; Yun-Ju Lai; Damien Wittwer; Matthew A. Hopcroft; Albert P. Pisano

    2010-01-01

    This paper reports fine frequency selection techniques for aluminum nitride (AlN) Lamb wave mode resonators (LWR) to control the relative frequency of resonators in an array to 0.1%. The technique that works the best is by adjusting the so-called AlN “overhang” dimension, OH, measured from the center of the outermost electrode to the edge of AlN plate independently of the

  7. Novel Magnetic Resonance Imaging Techniques in Brain Tumors.

    PubMed

    Nechifor, Ruben E; Harris, Robert J; Ellingson, Benjamin M

    2015-06-01

    Magnetic resonance imaging is a powerful, noninvasive imaging technique with exquisite sensitivity to soft tissue composition. Magnetic resonance imaging is primary tool for brain tumor diagnosis, evaluation of drug response assessment, and clinical monitoring of the patient during the course of their disease. The flexibility of magnetic resonance imaging pulse sequence design allows for a variety of image contrasts to be acquired, including information about magnetic resonance-specific tissue characteristics, molecular dynamics, microstructural organization, vascular composition, and biochemical status. The current review highlights recent advancements and novel approaches in MR characterization of brain tumors. PMID:26049817

  8. 35Cl NQR of 1,5,2-Diazaphosphorine Derivatives

    NASA Astrophysics Data System (ADS)

    Dolgushin, G. V.; Nikitin, P. A.; Sapozhnikov, Yu. E.; Dmitrichenko, M. Yu.; Rozinov, V. G.; Voronkov, M. G.

    1994-02-01

    NQR frequencies and asymmetry parameters (?) of 35Cl chlorine-containing 1,5,2-diazaphosphorine derivatives are reported and discussed. NMDO calculations with total optimization of geometry have been carried out. The ?cal and ?cal values, calculated by means of the Townes and Dailey theory, correlate well with the experimenal data.

  9. Studies of the electronic structure and biological activity of chosen 1,4-benzodiazepines by 35Cl NQR spectroscopy and DFT calculations

    NASA Astrophysics Data System (ADS)

    Bronisz, K.; Ostafin, M.; Poleshchuk, O. Kh.; Mielcarek, J.; Nogaj, B.

    2006-11-01

    Selected derivatives of 1,4-benzodiazepine: lorazepam, lormetazepam, oxazepam and temazepam, used as active substances in anxiolytic drugs, have been studied by 35Cl NQR method in order to find the correlation between electronic structure and biological activity. The 35Cl NQR resonance frequencies ( ?Q) measured at 77 K have been correlated with the following parameters characterising their biological activity: biological half-life period ( t0.5), affinity to benzodiazepine receptor (IC 50) and mean dose equivalent. The results of experimental study of some benzodiazepine derivatives by nuclear quadrupole resonance of 35Cl nuclei are compared with theoretical results based on DFT calculations which were carried out by means of Gaussian'98 W software.

  10. Narcotics and explosives detection by 14N pure nuclear quadrupole resonance

    NASA Astrophysics Data System (ADS)

    Garroway, Allen N.; Buess, Michael L.; Yesinowski, James P.; Miller, Joel B.

    1994-03-01

    Pure nuclear quadrupole resonance (NQR) of 14N nuclei is quite promising as a method for detecting explosives such as RDX and contraband narcotics such as cocaine and heroin in quantities of interest. Pure NQR is conducted without an external applied magnetic field, so potential concerns about damage to magnetically encoded data or exposure of personnel to large magnetic fields are not relevant. Because NQR frequencies of different compounds are quite distinct, we do not encounter false alarms from the NQR signals of other benign materials. We have constructed a proof-of-concept NQR explosives detector which interrogates a volume of 300 liters (10 ft3). With minimal modification to the existing explosives detector, we can detect operationally relevant quantities of (free base) cocaine within the 300-liter inspection volume in 6 seconds. We are presently extending this approach to the detection of heroin base and also examining 14N and 35,37Cl pure NQR for detection of the hydrochloride forms of both materials. An adaptation of this NQR approach may be suitable for scanning personnel for externally carried contraband and explosives. We first outline the basics of the NQR approach, highlighting strengths and weaknesses, and then present representative results for RDX and cocaine detection. We also present a partial compendium of relevant NQR parameters measured for some materials of interest.

  11. Low-power stimulated emission nuclear quadrupole resonance detection system utilizing Rabi transitions

    NASA Astrophysics Data System (ADS)

    Apostolos, John; Mouyos, William; Feng, Judy; Chase, Walter

    2013-06-01

    The application of CW radar techniques to Nuclear Quadrupole Resonance (NQR) detection of nitrogen based explosives and chlorine based narcotics enables the use of low power levels, in the range of 10's of watts, to yield high signal strengths. By utilizing Rabi transitions the nucleus oscillates between states one and two under the time dependent incident electromagnetic field and alternately absorbs energy from the incident field while emitting coherent energy via stimulated emission. Through the application of a cancellation algorithm the incident field is eliminated from the NQR response, allowing the receive signal to be measured while transmitting. The response signal is processed using matched filters of the NQR response which enables the direct detection of explosives. This technology has applicability to the direct detection of explosives and narcotics for security screening, all at safe low power levels, opposed to the current XRay and Millimeter wave screening systems that detect objects that may contain explosives and utilize high power. The quantum mechanics theoretical basis for the approach and an application for a system for security screening are described with empirical results presented to show the effects observed.

  12. A general numerical analysis of time-domain NQR experiments

    Microsoft Academic Search

    Elad Harel; Herman M. Cho

    2006-01-01

    We introduce a general numerical approach for solving the Liouville equation of an isolated quadrupolar nuclide that can be used to analyze the unitary dynamics of time-domain NQR experiments. A numerical treatment is necessitated by the dimensionality of the Liouville space, which precludes analytical, closed form solutions for I>3\\/2. Accurate simulations of experimental nutation curves, forbidden transition intensities, powder and

  13. NMR and NQR study of the thermodynamically stable quasicrystals

    SciTech Connect

    Shastri, A.

    1995-02-10

    {sup 27}Al and {sup 61,65}Cu NMR measurements are reported for powder samples of stable AlCuFe and AlCuRu icosahedral quasicrystals and their crystalline approximants, and for a AlPdMn single grain quasicrystal. Furthermore, {sup 27}Al NQR spectra at 4.2 K have been observed in the AlCuFe and AlCuRu samples. From the quadrupole perturbed NMR spectra at different magnetic fields, and from the zero field NQR spectra, a wide distribution of local electric field gradient (EFG) tensor components and principal axis system orientations was found at the Al site. A model EFG calculation based on a 1/1 AlCuFe approximant was successful in explaining the observed NQR spectra. It is concluded that the average local gradient is largely determined by the p-electron wave function at the Al site, while the width of the distribution is due to the lattice contribution to the EFG. Comparison of {sup 63}Cu NMR with {sup 27}Al NMR shows that the EFG distribution at the two sites is similar, but that the electronic contribution to the EFG is considerably smaller at the Cu site, in agreement with a more s-type wave function of the conduction electrons.

  14. NMR and NQR investigations of local symmetry in the hidden order phase of URu2Si2

    NASA Astrophysics Data System (ADS)

    Mito, T.; Hattori, M.; Motoyama, G.; Sakai, Y.; Koyama, T.; Ueda, K.; Kohara, T.; Yokoyama, M.; Amitsuka, H.

    2012-12-01

    In order to study local symmetries at the 4e(Si)- and 4d(Ru)-sites above and below hidden order transition temperature TO = 17.5 K in URu2Si2, we have investigated the nuclear quadrupole interaction by 73Ge-nuclear magnetic resonance (NMR) measurement on a 10% 73Ge-substituted sample URu2(Si0.9Ge0.1)2, and by 101Ru-nuclear quadrupole resonance (NQR) measurement on a pure single crystal sample. The present 73Ge-NMR measurements do not give any evidence for change in the local symmetry at 4e-site within experimental accuracy. On the other hand, the precise measurement of 101Ru-NQR frequency has detected an anomaly just below TO as sensitively as the thermal expansion measurement dose. Its temperature dependence shows a linear relation with that of the in-plane lattice parameter, which may be a clue to clarify a modification in microscopic charge distribution at TO.

  15. NQR 127I Spectroscopy of Layered Inorganic Compounds Intercalated with Aromatic Amines

    NASA Astrophysics Data System (ADS)

    Babushkina, T. A.; Seryukova, I. V.

    1998-07-01

    NQR spectroscopy was used to study the intercalating influence on the iodine electric field gradient of lead(ll) and cadmium(ll) iodides. We used pyridine, piperidine, aniline and quinoline, as guest substances. In the intercalates the NQR frequencies and their dependence on temperature in different crystalline phases were studied. The peculiarities of chemical bonds and crystal structures were discussed.

  16. Experimental Test of New Technique to Overcome Spin Depolarizing Resonances

    SciTech Connect

    Raymond, R. S.; Chao, A. W.; Krisch, A. D.; Leonova, M. A.; Morozov, V. S.; Sivers, D. W.; Wong, V. K. [Spin Physics Center, University of Michigan, Ann Arbor, MI 48109-1040 (United States); Ganshvili, A.; Gebel, R.; Lehrach, A.; Lorentz, B.; Maier, R.; Prasuhn, D.; Stockhorst, H.; Welsch, D. [Forschungszentrum Juelich, Institut fuer Kernphysik, Postfach 1913, D52425 Juelich (Germany); Hinterberger, F. [Helmholtz-Institut fuer Stahlen- und Kernphysik, Universitaet Bonn, D-53115 Bonn (Germany); Kondratenko, A. M. [GOO Zaryad, Russkaya St. 41, Novosibirsk, 630058 (Russian Federation)

    2009-08-04

    We recently tested a new spin resonance crossing technique, Kondratenko Crossing (KC) by sweeping an rf solenoid's frequency through an rf-induced spin resonance with both the KC an traditional Fast Crossing (FC) patterns. Using both rf bunched and unbunched 1.85 GeV/c polarized deuterons stored in COSY, we varied the parameters of both crossing patterns. Compared to FC with the same crossing speed, KC reduced the depolarization by measured factors of 4.7+-0.3 and 19+-{sub 5}{sup 12} for unbunched and bunched beams, respectively. This clearly showed the large potential benefit of Kondratenko Crossing over Fast Crossing.

  17. Nuclear quadrupole resonance studies of the SORC sequence and nuclear magnetic resonance studies of polymers

    SciTech Connect

    Jayakody, J.R.P.

    1993-12-31

    The behavior of induction signals during steady-state pulse irradiation in {sup 14}N NQR was investigated experimentally. Because Strong Off-resonance Comb (SORC) signals recur as long as the pulsing continues, very efficient signal-averaging can result. The dependence of these steady-state SORC signals on pulse parameters and on frequency offset are presented, together with a discussion of the applicability of the method. Also as part of the NQR work, cocaine base has been detected using conventional NQR techniques. The experimental results show that SORC detection can be of sufficient sensitivity to form the basis of narcotics screening devices for both mail and airline baggage. A new NMR technique, to obtain the correlation time of the random thermal motion of a polymer at temperatures near the glass transition has been introduced. The temperature dependence is a result of thermal motion. For slow-motion of a polymer chain near the glass transition, the CSA parameter begins to decrease. This motional narrowing can be interpreted to yield the correlation time of the thermal motion. In this work nitrocellulose isotopically highly enriched with {sup 15}N was studied at four different temperatures between 27{degrees} and 120{degrees} Celsius and the correlation times for polymer backbone motions were obtained. Naflon films containing water (D{sub 2}O and H{sub 2} {sup 17}O) and methanol (CH{sub 3}OD, CH{sub 3} {sup 17}OH), have been studied using deuteron and oxygen-17 NMR spectroscopy. Glassy behavior of the water domains at low temperature is evidenced by the specific nature of the {sup 2}H NMR lineshapes. Activation energies extracted from {sup 2}H spin-lattice relaxation data on the high temperature side of the T{sub 1} minimum exhibit a steady increase with increasing water content. In spite of a high degree of molecular mobility, angular-dependent spectra of both unstretched and stretched samples reflect considerable anisotrophy of the host polymer.

  18. I: Low Frequency NMR and NQR Using a dc SQUID. II: Variable-temperature 13C CP/MAS of Organometallics

    SciTech Connect

    Ziegeweid, M.A.

    1995-11-29

    NMR and NQR at low frequencies are difficult prospects due to small nuclear spin polarization. Furthermore, the sensitivity'of the inductive pickup circuitry of standard spectrometers is reduced as the frequency is lowered. I have used a cw-SQUID (Superconducting QUantum Interference Device) spectrometer, which has no such frequency dependence, to study the local atomic environment of {sup 14}N via the quadrupolar interaction. Because {sup 14}N has spin I = 1 and a 0-6 MHz frequency range, it is not possible to obtain well-resolved spectra in high magnetic fields. I have used a technique to observe {sup 14}N NQR resonances via their effect on neighboring protons mediated by the heteronuclear dipolar interaction to study peptides and narcotics. The sensitivity of the SQUID is not enough to measure low-frequency surface (or other low spin density) systems. The application of spin-polarized xenon has been previously used to enhance polarization in conventional NMR experiments. Because xenon only polarizes spins with which it is in contact, it is surface selective. While differences in chemical shifts between surface and bulk spins are not large, it is expected that the differences in quadrupole coupling constant should be very large due to the drastic change of the electric field gradient surrounding spins at the surface. With this in mind, I have taken preliminary steps to measure SQUID detected polarization transfer from Xe to another spin species at 4.2 K and in small magnetic fields (<50 G). In this regime, the spin-lattice relaxation of xenon is dependent on the applied magnetic field. The results of our efforts to characterize the relaxation of xenon are presented. The final section describes the solid-state variable-temperature (VT) one- and two-dimensional {sup 13}C cross polarization (CP)/magic angle spinning (MAS) NMR of Hf({eta}{sup 5}-C{sub 5}H{sub 5}){sub 2}({eta}{sup 1}-C{sub 5}H{sub 5}){sub 2}, Zr({eta}{sup 5}-C{sub 5}H{sub 5}){sub 3}({eta}{sup 1}-C{sub 5}H{sub 5}) and Sn({eta}{sup 1}-C{sub 5}H{sub 5}){sub 4}. This work was undertaken in the hope of gaining insight into the intramolecuhrr dynamics, specifically which fluxional processes exist in the solid state, by what mechanism rearrangements are occurring, and the activation energies by which these processes are governed.

  19. Off-resonance effects and selectivity profiles in pulsed nitrogen-14 nuclear quadrupole resonance.

    PubMed

    Guendouz, L; Robert, A; Retournard, A; Leclerc, S; Aissani, S; Canet, D

    2012-01-01

    In order to alleviate base-line distortions in nitrogen-14 NQR spectra originating from pulse breakthrough, low power radio-frequency (rf) pulses were applied. It is recalled that the required power is four times lower than that for an equivalent NMR experiment. This is easily explained by the fact that, in NMR, half the amplitude of the rf field is active. Moreover, the selectivity profile (i.e. the peak amplitude as a function of the difference between the carrier frequency and the resonance frequency) exhibits a shape which is, in most cases, more favorable in NQR than in NMR. An appropriate theory has been developed for explaining these experimental observations. It is concluded that low power NQR is perfectly feasible and should even be recommended for most applications, provided that the line-width of the NQR signal is not too large. PMID:23063174

  20. Surface Plasmon Resonance: A Versatile Technique for Biosensor Applications

    PubMed Central

    Nguyen, Hoang Hiep; Park, Jeho; Kang, Sebyung; Kim, Moonil

    2015-01-01

    Surface plasmon resonance (SPR) is a label-free detection method which has emerged during the last two decades as a suitable and reliable platform in clinical analysis for biomolecular interactions. The technique makes it possible to measure interactions in real-time with high sensitivity and without the need of labels. This review article discusses a wide range of applications in optical-based sensors using either surface plasmon resonance (SPR) or surface plasmon resonance imaging (SPRI). Here we summarize the principles, provide examples, and illustrate the utility of SPR and SPRI through example applications from the biomedical, proteomics, genomics and bioengineering fields. In addition, SPR signal amplification strategies and surface functionalization are covered in the review. PMID:25951336

  1. Current modulation technique used in resonator micro-optic gyro.

    PubMed

    Lei, Ming; Feng, Lishuang; Zhi, Yinzhou; Liu, Huilan; Wang, Junjie; Ren, Xiaoyuan; Su, Ni

    2013-01-10

    Resonator micro-optic gyro (RMOG) is a promising candidate for the next generation inertial rotation sensor based on the Sagnac effect. A current modulation technique used in an external cavity laser diode is proposed to construct the gyroscope system for the first time. The resonance curves before and after eliminating accompanying amplitude modulation are theoretically analyzed, calculated, and simulated; the demodulation curves with different modulation currents are formulated theoretically; and the optimum modulation current corresponding to the maximum sensitivity is obtained. The experiment results from the established RMOG experimental setup demonstrate that a bias stability of 2.7 deg/s (10 s integrated time) over 600 s, and dynamic range of ±500 deg/s are demonstrated in an RMOG with a silica optical waveguide ring resonator having a ring length of 12.8 cm. PMID:23314650

  2. Munitions classification using an Acoustic Resonance Spectroscopic technique

    SciTech Connect

    Roberts, R.S.; Chen, J.T.; Vela, O.A.; Lewis, P.S.

    1993-12-01

    In support of the Bilateral Chemical Weapons Agreement between the United States and Russia, Los Alamos National Laboratory has developed a nondestructive evaluation (NDE) technique that discriminates between different types of artillery munitions. This NDE classification technique allows on-site inspectors to rapidly classify the munitions as chemical or high explosive, and furthermore discriminates between various subclasses of these types of munitions. This technique, based on acoustic resonance measurements, has been successfully demonstrated on a wide variety of high explosive and chemical munitions. The technique consists of building templates of spectral features from sets of known munitions. Spectral features of unknown munitions are compared with a library of templates, and the degree of match between the features and the templates is used to classify the munition. This paper describes the technique, including the feature extraction, clustering and classification algorithms.

  3. Total body water measurements using resonant cavity perturbation techniques.

    PubMed

    Stone, Darren A; Robinson, Martin P

    2004-05-01

    A recent paper proposed a novel technique for determining the total body water (TBW) of patients suffering with abnormal hydration levels, using a resonant cavity perturbation method. Current techniques to measure TBW are limited by resolution and technical constraints. However, this new method involves measuring the dielectric properties of the body, by placing a subject in a large cavity resonator and measuring the subsequent change in its resonant frequency, fres and its Q-factor. Utilizing the relationship that water content correlates to these dielectric properties, it has been shown that the measured response of these parameters enables determination of TBW. Results are presented for a preliminary study using data estimated from anthropometric measurements, where volunteers were asked to lie and stand in an electromagnetic screened room, before and after drinking between 1 and 2 l of water, and in some cases, after voiding the bladder. Notable changes in the parameters were observed; fres showed a negative shift and Q was reduced. Preliminary calibration curves using estimated values of water content have been developed from these results, showing that for each subject the measured resonant frequency is a linear function of TBW. Because the gradients of these calibration curves correlate to the mass-to-height-ratio of the volunteers, it has proved that a system in which TBW can be unequivocally obtained is possible. Measured values of TBW have been determined using this new pilot-technique, and the values obtained correlate well with theoretical values of body water (r = 0.87) and resolution is very good (750 ml). The results obtained are measurable, repeatable and statistically significant. This leads to confidence in the integrity of the proposed technique. PMID:15152930

  4. Cottonseed oil estimation by pulsed nuclear magnetic resonance technique

    Microsoft Academic Search

    V. T. Srinivasan; B. B. Singh; P. K. Chidambareswaran; V. Sundaram

    1985-01-01

    Seed asymmetry and moisture associated with the seeds are known to affect seed oil estimation by pulsed nuclear magnetic resonance\\u000a (NMR) technique employing free induction decay or single spin echo (SE) pulse sequence. UsingGossypium (cottonseeds) as experimental material, it is shown that transverse relaxation times (T2) of seed oil, in different varieties of seeds, measured in vivo, are not the

  5. Total body water measurements using resonant cavity perturbation techniques

    NASA Astrophysics Data System (ADS)

    Stone, Darren A.; Robinson, Martin P.

    2004-05-01

    A recent paper proposed a novel technique for determining the total body water (TBW) of patients suffering with abnormal hydration levels, using a resonant cavity perturbation method. Current techniques to measure TBW are limited by resolution and technical constraints. However, this new method involves measuring the dielectric properties of the body, by placing a subject in a large cavity resonator and measuring the subsequent change in its resonant frequency, fres and its Q-factor. Utilizing the relationship that water content correlates to these dielectric properties, it has been shown that the measured response of these parameters enables determination of TBW. Results are presented for a preliminary study using data estimated from anthropometric measurements, where volunteers were asked to lie and stand in an electromagnetic screened room, before and after drinking between 1 and 2 l of water, and in some cases, after voiding the bladder. Notable changes in the parameters were observed; fres showed a negative shift and Q was reduced. Preliminary calibration curves using estimated values of water content have been developed from these results, showing that for each subject the measured resonant frequency is a linear function of TBW. Because the gradients of these calibration curves correlate to the mass-to-height-ratio of the volunteers, it has proved that a system in which TBW can be unequivocally obtained is possible. Measured values of TBW have been determined using this new pilot-technique, and the values obtained correlate well with theoretical values of body water (r = 0.87) and resolution is very good (750 ml). The results obtained are measurable, repeatable and statistically significant. This leads to confidence in the integrity of the proposed technique.

  6. Reliable and integrated technique for determining resonant frequency in radio frequency resonators. Application to a high-precision resonant cavity-based displacement sensor.

    PubMed

    Jauregui, Rigoberto; Asua, Estibaliz; Portilla, Joaquin; Etxebarria, Victor

    2015-03-01

    This paper presents a reliable and integrated technique for determining the resonant frequency of radio frequency resonators, which can be of interest for different purposes. The approach uses a heterodyne scheme as phase detector coupled to a voltage-controlled oscillator. The system seeks the oscillator frequency that produces a phase null in the resonator, which corresponds to the resonant frequency. A complete explanation of the technique to determine the resonant frequency is presented and experimentally tested. The method has been applied to a high-precision displacement sensor based on resonant cavity, obtaining a theoretical nanometric precision. PMID:25832260

  7. Successive Phase Transitions and High Ionic Conductivity of Trichlorogermanate (II) Salts as Studied by 35C1 NQR and Powder X-Ray Diffraction

    NASA Astrophysics Data System (ADS)

    Yamada, K.; Isobe, K.; Okuda, T.; Furukawa, Y.

    1994-02-01

    A series of trichlorogermanate(II) salts (AGeCl3, A = Rb, Cs, CH3N H3, and (CH3)4N) have been synthesized and characterized by 35Cl NQR , 35Cl NMR , AC conductivity, DTA, and X-ray diffraction techniques. In the temperature range studied two, two, five, and four phases were confirmed for the Rb, Cs, CH3NH3, and (CH3)4N salts, respectively. From the 35Cl NQR and structural data, isolated pyramidal GeCl3 anions were recognized in the low temperature phases. With increasing temperature the relaxation times of the 35Cl NQR decreased exponentially and the signals disappeared far below the melting point. This suggests that the reorientation of the anion about the pseudo three-fold axis is excited. With further increase in temperature, the ionic conductivity of CH3NH3GeCl3 and (CH3)4NGeCl3 increased drastically at the phase transitions to their cubic perovskite phases (CH3NH3GeCl3:?= 10-1 Sm-1 at 400 K, (CH3)4NGeCl3: ? = 5 x 10-2 Sm-1 at 420 K). The mobile ion was confirmed to be the chloride ion by means of 35Cl NMR and X-ray diffraction.

  8. Absence of Magnetic Dipolar Phase Transition and Evolution of Low-Energy Excitations in PrNb2Al20 with Crystal Electric Field ?3 Ground State: Evidence from 93Nb-NQR Studies

    NASA Astrophysics Data System (ADS)

    Kubo, Tetsuro; Kotegawa, Hisashi; Tou, Hideki; Higashinaka, Ryuji; Nakama, Akihiro; Aoki, Yuji; Sato, Hideyuki

    2015-07-01

    We report measurements of bulk magnetic susceptibility and 93Nb nuclear quadrupole resonance (NQR) in the Pr-based caged compound PrNb2Al20. By analyzing the magnetic susceptibility and magnetization, the crystal electric field (CEF) level scheme of PrNb2Al20 is determined to be ?3(0 K)-?4(21.32 K)-?5(43.98 K)-?1(51.16 K) within the framework of the localized 4f electron picture. The 93Nb-NQR spectra exhibit neither spectral broadening nor spectral shift upon cooling down to 75 mK. The 93Nb-NQR spin-lattice relaxation rate 1/T1 at 5 K depends on the frequency and remains almost constant below 5 K. The frequency dependence of 1/T1 is attributed to the magnetic fluctuation due to the hyperfine-enhanced 141Pr nuclear moment inherent in the nonmagnetic ?3 CEF ground state. The present NQR results provide evidence that no symmetry-breaking magnetic dipole order occurs down to 75 mK. Also, considering an invariant form of the quadrupole and octupole couplings between a 93Nb nucleus and Pr 4f electrons, Pr 4f quadrupoles and an octupole can couple with a 93Nb nuclear quadrupole moment and nuclear spin, respectively. Together with the results of bulk measurements, the present NQR results suggest that the possibility of a static quadrupole or octupole ordering can be excluded down to 100 mK. At low temperatures below 500 mK, however, the nuclear spin-echo decay rate gradually increases and the decay curve changes from Gaussian decay to Lorentzian decay, suggesting the evolution of a low-energy excitation.

  9. The two-frequency nuclear quadrupole resonance for explosives detection

    Microsoft Academic Search

    G. V. Mozjoukhine

    2000-01-01

    The two-frequency nuclear quadrupole resonance (NQR) of14N nuclei is described for purposes of explosives detection. Two applications are known: two-frequency NQR for increasing the\\u000a signal intensity, two-frequency NQR for improved reliability of explosives detection. The two-frequency experiments were carried\\u000a out in hexahydro-1,3,5-trinitro-s-triazine C3H6N6O6 and sodium nitrite NaNO2 as a substitute for octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocycine C4H8N8O8. The two-frequency sequences for NQR are proposed

  10. Novel technique in the segmentation of magnetic resonance image

    NASA Astrophysics Data System (ADS)

    Chan, Kwok-Leung

    1996-04-01

    In this investigation, automatic image segmentation is carried out on magnetic resonance image (MRI). A novel technique based on the maximum minimum measure is devised. The measure is improved by combining the smoothing and counting processes, and then normalizing the number of maximum and minimum positions over the region of interest (ROI). Two parameters (MM_H and MM_V) are generated and used for the segmentation. The technique is tested on some brain MRIs of a human male from the Visible Human Project of the National Library of Medicine, National Institutes of Health, USA. Preliminary results indicate that the maximum minimum measure can provide effective parameters for human tissue characterization and image segmentation with an added advantage of faster computation.

  11. Advanced Morphological and Functional Magnetic Resonance Techniques in Glaucoma

    PubMed Central

    Mastropasqua, Rodolfo; Agnifili, Luca; Mattei, Peter A.; Caulo, Massimo; Fasanella, Vincenzo; Navarra, Riccardo; Mastropasqua, Leonardo; Marchini, Giorgio

    2015-01-01

    Glaucoma is a multifactorial disease that is the leading cause of irreversible blindness. Recent data documented that glaucoma is not limited to the retinal ganglion cells but that it also extends to the posterior visual pathway. The diagnosis is based on the presence of signs of glaucomatous optic neuropathy and consistent functional visual field alterations. Unfortunately these functional alterations often become evident when a significant amount of the nerve fibers that compose the optic nerve has been irreversibly lost. Advanced morphological and functional magnetic resonance (MR) techniques (morphometry, diffusion tensor imaging, arterial spin labeling, and functional connectivity) may provide a means for observing modifications induced by this fiber loss, within the optic nerve and the visual cortex, in an earlier stage. The aim of this systematic review was to determine if the use of these advanced MR techniques could offer the possibility of diagnosing glaucoma at an earlier stage than that currently possible.

  12. Temperature and baric dependence of nuclear quadruple resonance spectra in indium and gallium monoselenides

    NASA Astrophysics Data System (ADS)

    Khandozhko, Victor; Raranskii, Nikolai; Balazjuk, Vitaly; Samila, Andriy; Kovalyuk, Zahar

    2013-12-01

    Pulsed radiospectroscopy method has been used to study nuclear quadruple resonance (NQR) spectra of 69Ga and 115In isotopes in the layered semiconductors GaSe and InSe. It has been found that in GaSe and InSe there is a considerable temperature dependence of NQR frequency which in the temperature range of 250 to 390 K is practically linear with conversion slope 1.54 kHz/degree for 69Ga and 2.35 kHz/degree for 115In. In the same crystals the effect of uniaxial pressure on NQR spectra applied along the optical axis ? up to the values of 500 kg/?m2 has been studied. A strong attenuation of NQR spectra intensity with increase in pressure on layered crystal package has been established. The unvaried multiplicity of resonance spectra indicates the absence of structural transformations in these layered crystals over the investigated range of temperatures and pressures.

  13. Nuclear quadrupole resonance lineshape analysis for different motional models: stochastic Liouville approach.

    PubMed

    Kruk, D; Earle, K A; Mielczarek, A; Kubica, A; Milewska, A; Moscicki, J

    2011-12-14

    A general theory of lineshapes in nuclear quadrupole resonance (NQR), based on the stochastic Liouville equation, is presented. The description is valid for arbitrary motional conditions (particularly beyond the valid range of perturbation approaches) and interaction strengths. It can be applied to the computation of NQR spectra for any spin quantum number and for any applied magnetic field. The treatment presented here is an adaptation of the "Swedish slow motion theory," [T. Nilsson and J. Kowalewski, J. Magn. Reson. 146, 345 (2000)] originally formulated for paramagnetic systems, to NQR spectral analysis. The description is formulated for simple (Brownian) diffusion, free diffusion, and jump diffusion models. The two latter models account for molecular cooperativity effects in dense systems (such as liquids of high viscosity or molecular glasses). The sensitivity of NQR slow motion spectra to the mechanism of the motional processes modulating the nuclear quadrupole interaction is discussed. PMID:22168707

  14. Magnetic correlations in La(2-x)Sr(x)CuO4 from NQR relaxation and specific heat

    NASA Technical Reports Server (NTRS)

    Borsa, F.; Rigamonti, A.

    1991-01-01

    La-139 and Cu-63 Nuclear Quadrupole Resonance (NQR) relaxation measurements in La(2-x)Sr(x)CuO4 for x ranging from 0 up to 0.3, with particular emphasis on the effect of doping on the Cu(2+) magnetic correlations and dynamics, are reviewed. In the low doping limit, x less than or equal to 0.05, the results can be interpreted consistently in terms of a simple phenomenological 'two-fluids' model whereby the effect of thermally-activated mobile O(2p) holes is the one of disrupting locally the Cu(2+) spin correlations. For x greater than or equal to 0.1, the results indicate the onset, as T approaches T(sub c)(+), of a strong coupling between Cu(2+) spins and the Fermi liquid of O(2p) holes leading to the apparent disappearance of localized Cu(2+) moment in connection with the opening of a superconducting gap.

  15. Copper Nqr and NMR Study of Metal-Substituted Yttrium BARIUM(2) COPPER(3) OXYGEN(7) and Yttrium BARIUM(2) COPPER(4) OXYGEN(8)

    NASA Astrophysics Data System (ADS)

    Cheng, Show-Jye

    Pulsed nuclear quadrupole resonance (NQR) and nuclear magnetic resonance (NMR) have been used to investigate the effect of metal-substitution for copper in YBa_2Cu_3O_7 (YBCO123) and YBa_2Cu_4O_8 (YBCO124). Among many metal substitutions, Zn has an especially dramatic effect in suppressing the superconducting temperature T_{c}, and hence superconductivity. More interesting is that Zn and Fe have the same T_{c} suppression effect in YBCO124. This study focuses on the Zn substitutions in YBCO123 and Zn, Fe, and Co substitutions in YBCO124. In Zn doped YBCO123, Cu(2), plane site, NQR spectra and the frequency dependence of the spin-lattice relaxation rates have been measured over a temperature range from 77 K to 300 K to study the correlation of the suppression of the relaxation rate with the distance between the probe Cu nuclei and the impurity. It is found that the relaxation rate is insensitive to the variation of the NQR resonance frequency. However, by comparing the results of the Zn doped YBCO124 with those of YBCO123, it can be concluded that the suppression of the relaxation rate for both YBCO compounds in the normal state is caused by destruction of short-range antiferromagnetic correlation with substitution of nonmagnetic ion Zn on the Cu(2) sites. NQR and NMR measurements were carried out on both Cu(2), plane, and Cu(1), chain sites, for various concentrations of Zn, Fe, and Co dopants in YBCO124 over a temperature range from 77 K to 300 K. A strong correlation of the enhancement of Cu(2) spin lattice relaxation rate and suppression of superconductivity by impurities was found. The temperature dependence of the Cu(2) NMR linewidth exhibits a strong RKKY type exchange interaction below 225 K for Zn and Fe doped samples, which indicates the formation of the local magnetic moment. The enhancement of the relaxation rate is caused by the local magnetic moment Fe^ {+3} ion and the moments on Cu(2) neighbors when Zn^{+2} is substituted on Cu(2). This study gives us a clear picture of the spin pseudogap behavior in the high temperature superconductor cuprates. It also suggests that the magnetic moment on the CuO_2 plane may relate to the suppression of T_{c} in metal-substituted YBCO124.

  16. Unconventional nuclear magnetic resonance techniques using nanostructured diamond surfaces

    NASA Astrophysics Data System (ADS)

    Acosta, Victor; Jarmola, Andrey; Budker, Dmitry; Santori, Charles; Huang, Zhihong; Beausoleil, Raymond

    2014-03-01

    Nuclear magnetic resonance (NMR) technologies rely on obtaining high nuclear magnetization, motivating low operating temperatures and high magnetic fields. Dynamic nuclear polarization (DNP) techniques traditionally require another superconducting magnet and THz optics. We seek to use chip-scale devices to polarize nuclei in liquids at room temperature. The technique relies on optical pumping of nitrogen-vacancy (NV) centers and subsequent transfer of polarization to nuclei via hyperfine interaction, spin diffusion, and heteronuclear polarization transfer. We expect efficient polarization transfer will be realized by maximizing the diamond surface area. We have fabricated densely-packed (50 % packing fraction), high-aspect-ratio (10+) nanopillars over mm2 regions of the diamond surface. Pillars designed to have a few-hundred-nanometer diameter act as optical antennas, reducing saturation intensity. We also report progress in using nanopillar arrays as sensitive optical detectors of nano-scale NMR by measuring NV center Zeeman shifts produced by nearby external nuclei. The enhanced surface area increases the effective density of NV centers which couple to external nuclei. Combining these techniques may enable, e.g., identification of trace analytes and molecular imaging.

  17. Resonant frequency calculations using a hybrid perturbation-Galerkin technique

    NASA Technical Reports Server (NTRS)

    Geer, James F.; Andersen, Carl M.

    1991-01-01

    A two-step hybrid perturbation Galerkin technique is applied to the problem of determining the resonant frequencies of one or several degree of freedom nonlinear systems involving a parameter. In one step, the Lindstedt-Poincare method is used to determine perturbation solutions which are formally valid about one or more special values of the parameter (e.g., for large or small values of the parameter). In step two, a subset of the perturbation coordinate functions determined in step one is used in Galerkin type approximation. The technique is illustrated for several one degree of freedom systems, including the Duffing and van der Pol oscillators, as well as for the compound pendulum. For all of the examples considered, it is shown that the frequencies obtained by the hybrid technique using only a few terms from the perturbation solutions are significantly more accurate than the perturbation results on which they are based, and they compare very well with frequencies obtained by purely numerical methods.

  18. Magnetic Resonance Elastography of Liver: Technique, Analysis and Clinical Applications

    PubMed Central

    Venkatesh, Sudhakar K; Yin, Meng; Ehman, Richard L

    2012-01-01

    Many pathological processes cause marked changes in the mechanical properties of tissue. Magnetic Resonance Elastography (MRE) is a non-invasive MRI based technique for quantitatively assessing the mechanical properties of tissues in vivo. MRE is performed by using a vibration source to generate low frequency mechanical waves in tissue, imaging the propagating waves using a phase contrast MRI technique, and then processing the wave information to generate quantitative images showing mechanical properties such as tissue stiffness. Since its first description in 1995, published studies have explored many potential clinical applications including brain, thyroid, lung, heart, breast, and skeletal muscle imaging. However, the best-documented application to emerge has been the use of MRE to assess liver disease. Multiple studies have demonstrated that there is a strong correlation between MRE-measured hepatic stiffness and the stage of fibrosis at histology. The emerging literature indicates that MRE can serve as a safer, less expensive, and potentially more accurate alternative to invasive liver biopsy which is currently the gold standard for diagnosis and staging of liver fibrosis. This review describes the basic principles, technique of performing a liver MRE, analysis and calculation of stiffness, clinical applications, limitations, and potential future applications. PMID:23423795

  19. Resonant frequency calculations using a hybrid perturbation-Galerkin technique

    NASA Technical Reports Server (NTRS)

    Geer, James F.; Andersen, Carl M.

    1991-01-01

    A two-step hybrid perturbation Galerkin technique is applied to the problem of determining the resonant frequencies of one or several degrees of freedom nonlinear systems involving a parameter. In one step, the Lindstedt-Poincare method is used to determine perturbation solutions which are formally valid about one or more special values of the parameter (e.g., for large or small values of the parameter). In step two, a subset of the perturbation coordinate functions determined in step one is used in Galerkin type approximation. The technique is illustrated for several one degree of freedom systems, including the Duffing and van der Pol oscillators, as well as for the compound pendulum. For all of the examples considered, it is shown that the frequencies obtained by the hybrid technique using only a few terms from the perturbation solutions are significantly more accurate than the perturbation results on which they are based, and they compare very well with frequencies obtained by purely numerical methods.

  20. Magnetic resonance techniques for investigation of multiple sclerosis

    NASA Astrophysics Data System (ADS)

    MacKay, Alex; Laule, Cornelia; Li, David K. B.; Meyers, Sandra M.; Russell-Schulz, Bretta; Vavasour, Irene M.

    2014-11-01

    Multiple sclerosis (MS) is a common neurological disease which can cause loss of vision and balance, muscle weakness, impaired speech, fatigue, cognitive dysfunction and even paralysis. The key pathological processes in MS are inflammation, edema, myelin loss, axonal loss and gliosis. Unfortunately, the cause of MS is still not understood and there is currently no cure. Magnetic resonance imaging (MRI) is an important clinical and research tool for MS. 'Conventional' MRI images of MS brain reveal bright lesions, or plaques, which demark regions of severe tissue damage. Conventional MRI has been extremely valuable for the diagnosis and management of people who have MS and also for the assessment of therapies designed to reduce inflammation and promote repair. While conventional MRI is clearly valuable, it lack pathological specificity and, in some cases, sensitivity to non-lesional pathology. Advanced MR techniques have been developed to provide information that is more sensitive and specific than what is available with clinical scanning. Diffusion tensor imaging and magnetization transfer provide a general but non-specific measure of the pathological state of brain tissue. MR spectroscopy provides concentrations of brain metabolites which can be related to specific pathologies. Myelin water imaging was designed to assess brain myelination and has proved useful for measuring myelin loss in MS. To combat MS, it is crucial that the pharmaceutical industry finds therapies which can reverse the neurodegenerative processes which occur in the disease. The challenge for magnetic resonance researchers is to design imaging techniques which can provide detailed pathological information relating to the mechanisms of MS therapies. This paper briefly describes the pathologies of MS and demonstrates how MS-associated pathologies can be followed using both conventional and advanced MR imaging protocols.

  1. Localization and Function of the Membrane-bound Riboflavin in the Na+-translocating NADH:Quinone Oxidoreductase (Na+-NQR) from Vibrio cholerae*

    PubMed Central

    Casutt, Marco S.; Huber, Tamara; Brunisholz, René; Tao, Minli; Fritz, Günter; Steuber, Julia

    2010-01-01

    The sodium ion-translocating NADH:quinone oxidoreductase (Na+-NQR) from the human pathogen Vibrio cholerae is a respiratory membrane protein complex that couples the oxidation of NADH to the transport of Na+ across the bacterial membrane. The Na+-NQR comprises the six subunits NqrABCDEF, but the stoichiometry and arrangement of these subunits are unknown. Redox-active cofactors are FAD and a 2Fe-2S cluster on NqrF, covalently attached FMNs on NqrB and NqrC, and riboflavin and ubiquinone-8 with unknown localization in the complex. By analyzing the cofactor content and NADH oxidation activity of subcomplexes of the Na+-NQR lacking individual subunits, the riboflavin cofactor was unequivocally assigned to the membrane-bound NqrB subunit. Quantitative analysis of the N-terminal amino acids of the holo-complex revealed that NqrB is present in a single copy in the holo-complex. It is concluded that the hydrophobic NqrB harbors one riboflavin in addition to its covalently attached FMN. The catalytic role of two flavins in subunit NqrB during the reduction of ubiquinone to ubiquinol by the Na+-NQR is discussed. PMID:20558724

  2. Measurement techniques for magnetic resonance imaging of fast relaxing nuclei.

    PubMed

    Konstandin, Simon; Nagel, Armin M

    2014-02-01

    In this review article, techniques for sodium ((23)Na) magnetic resonance imaging (MRI) are presented. These techniques can also be used to image other nuclei with short relaxation times (e.g., (39)K, (35)Cl, (17)O). Twisted projection imaging, density-adapted 3D projection reconstruction, and 3D cones are preferred because of uniform k-space sampling and ultra-short echo times. Sampling density weighted apodization can be applied if intrinsic filtering is desired. This approach leads to an increased signal-to-noise ratio compared to postfiltered acquisition in cases of short readout durations relative to T 2 (*) relaxation time. Different MR approaches for anisotropic resolution are presented, which are important for imaging of thin structures such as myocardium, cartilage, and skin. The third part of this review article describes different methods to put more weighting either on the intracellular or the extracellular sodium signal by means of contrast agents, relaxation-weighted imaging, or multiple-quantum filtering. PMID:23881004

  3. Experimental implementation of quantum information processing by Zeeman-perturbed nuclear quadrupole resonance

    NASA Astrophysics Data System (ADS)

    Teles, Joăo; Rivera-Ascona, Christian; Polli, Roberson S.; Oliveira-Silva, Rodrigo; Vidoto, Edson L. G.; Andreeta, José P.; Bonagamba, Tito J.

    2015-03-01

    Nuclear magnetic resonance (NMR) has been widely used in the context of quantum information processing (QIP). However, despite the great similarities between NMR and nuclear quadrupole resonance (NQR), no experimental implementation for QIP using NQR has been reported. We describe the implementation of basic quantum gates and their applications on the creation and manipulation of pseudopure states using linearly polarized radiofrequency pulses under static magnetic field perturbation. The NQR quantum operations were implemented using a single-crystal sample of {KClO}3 and observing ^{35}{Cl} nuclei, which possess spin 3/2 and give rise to a two-qubit system. The results are very promising and indicate that NQR can be successfully used for performing fundamental experiments in QIP. One advantage of NQR in comparison with NMR is that the main interaction is internal to the sample, which makes the system more compact, lowering its cost and making it easier to be miniaturized to solid-state devices. Furthermore, as an example, the study of squeezed spin states could receive relevant contributions from NQR.

  4. Experimental implementation of quantum information processing by Zeeman-perturbed nuclear quadrupole resonance

    NASA Astrophysics Data System (ADS)

    Teles, Joăo; Rivera-Ascona, Christian; Polli, Roberson S.; Oliveira-Silva, Rodrigo; Vidoto, Edson L. G.; Andreeta, José P.; Bonagamba, Tito J.

    2015-06-01

    Nuclear magnetic resonance (NMR) has been widely used in the context of quantum information processing (QIP). However, despite the great similarities between NMR and nuclear quadrupole resonance (NQR), no experimental implementation for QIP using NQR has been reported. We describe the implementation of basic quantum gates and their applications on the creation and manipulation of pseudopure states using linearly polarized radiofrequency pulses under static magnetic field perturbation. The NQR quantum operations were implemented using a single-crystal sample of and observing nuclei, which possess spin 3/2 and give rise to a two-qubit system. The results are very promising and indicate that NQR can be successfully used for performing fundamental experiments in QIP. One advantage of NQR in comparison with NMR is that the main interaction is internal to the sample, which makes the system more compact, lowering its cost and making it easier to be miniaturized to solid-state devices. Furthermore, as an example, the study of squeezed spin states could receive relevant contributions from NQR.

  5. Colorimetric resonant reflection as a direct biochemical assay technique

    Microsoft Academic Search

    Brian Cunningham; Peter Li; Bo Lin; J. Pepper

    2002-01-01

    A novel approach for the detection of molecular interactions is presented in which a colorimetric resonant diffractive grating surface is used as a surface binding platform. A guided mode resonant phenomenon is used to produce an optical structure that, when illuminated with white light, is designed to reflect only a single wavelength. When molecules are attached to the surface, the

  6. Low Frequency NQR using Double Contact Cross-relaxation

    NASA Astrophysics Data System (ADS)

    Stephenson, David; Smith, John A. S.

    2000-02-01

    A cross-relaxation technique is described which involves two spin contacts per double reso-nance cycle. The result is an improvement in signal to noise ratio particularly at low frequencies. Experimental spectra and analyses are presented: 14N in ammonium sulphate showing that the tech-nique gives essentially the same information as previous studies; 14N in ammonium dichromate determining e2Qq/h as (76±3) kHz and ? = 0.84±.04; 7Li in lithium acetylacetonate for which the spectrum (corrected for Zeeman distortion) yields e2Qq/h = (152 ±5) kHz and ?=.5 ±.2. Calculated spectra are presented to demonstrate the ? dependence of the line shapes for 7Li.

  7. Nuclear Quadrupole Resonance Studies of the Sorc Sequence and Nuclear Magnetic Resonance Studies of Polymers.

    NASA Astrophysics Data System (ADS)

    Jayakody, Jayakody R. Pemadasa

    1993-01-01

    The behavior of induction signals during steady -state pulse irradiation in ^{14} N NQR was investigated experimentally. Because Strong Off-resonance Comb (SORC) signals recur as long as the pulsing continues, very efficient signal-averaging can result. The dependence of these steady-state SORC signals on pulse parameters and on frequency offset are presented, together with a discussion of the applicability of the method. Also as part of the NQR work, Cocaine base has been detected using conventional NQR techniques. The experimental results show that SORC detection can be of sufficient sensitivity to form the basis of narcotics screening devices for both mail and airline baggage. A new NMR technique, to obtain the correlation time of the random thermal motion of a polymer at temperatures near the glass transition has been introduced. The temperature dependence is a result of thermal motion. For slow-motion of a polymer chain near the glass transition, the CSA parameter begins to decrease. This motional narrowing can be interpreted to yield the correlation time of the thermal motion. In this work Nitrocellulose isotopically highly enriched with ^{15}N was studied at four different temperatures between 27^ circ and 120^circ Celsius and the correlation times for polymer backbone motions were obtained. Nafion films containing, water (D_2 O and H_2^{17}O) and methanol (CH_3OD, CH _3^{17}OH), have been studied using Deuteron and Oxygen-17 NMR spectroscopy. Glassy behavior of the water domains at low temperature is evidenced by the specific nature of the ^2H NMR lineshapes. Activation energies extracted from ^2H spin-lattice relaxation data on the high temperature side of the T_1 minimum exhibit a steady increase with increasing water content. In spite of a high degree of molecular mobility, angular-dependent spectra of both unstretched and stretched samples reflect considerable anisotropy of the host polymer. Activation volumes corresponding to a specific dynamical process were obtained from measurements of spin-lattice relaxation vs. pressure. From the NMR measurements of Nafion films containing methanol, it was found that the molecular motion is much more rapid than the molecular motion of water in Nafion membranes.

  8. IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES 1 A Resonant Switch for LNA Protection

    E-print Network

    Kuhn, William B.

    IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES 1 A Resonant Switch for LNA Protection in Watt-Level Moussessian Abstract--An integrated resonant switch designed to protect low-noise amplifier (LNA) circuits at UHF through -band frequencies. Index Terms--CMOS transceivers, low-noise amplifier (LNA), transmit

  9. Resonant ultrasound spectroscopy (RUS) is a non-destructive technique originally developed for evaluating

    E-print Network

    RUS Resonant ultrasound spectroscopy (RUS) is a non- destructive technique originally developed of vibration observed in samples with regular geometry. RUS can also be used for non-destructive evaluation measurement results. Resonant ultrasound spectroscopy (RUS) is a non-destructive material characterisation

  10. Implementation of State Transfer Hamiltonians in Spin Chains with Magnetic Resonance Techniques

    E-print Network

    Cappellaro, Paola

    2014-01-01

    Nuclear spin systems and magnetic resonance techniques have provided a fertile platform for experimental investigation of quantum state transfer in spin chains. From the first observation of polarization transfer, predating ...

  11. Superconductivity and magnetic fluctuations in Cd(2))Re(2)O(7) via Cd nuclear magnetic resonance and re nuclear quadrupole resonance.

    PubMed

    Vyaselev, O; Arai, K; Kobayashi, K; Yamazaki, J; Kodama, K; Takigawa, M; Hanawa, M; Hiroi, Z

    2002-07-01

    We report Cd nuclear magnetic resonance (NMR) and Re nuclear quadrupole resonance (NQR) studies on Cd(2)Re(2)O(7), the first superconductor among pyrochlore oxides (T(c) approximately 1 K). The Re NQR spectrum at zero magnetic field below 100 K rules out any magnetic or charge order. The spin-lattice relaxation rate below T(c) exhibits a pronounced coherence peak and follows the weak-coupling BCS theory with nearly isotropic energy gap. The results of Cd NMR point to a moderate ferromagnetic enhancement at high temperatures followed by a rapid decrease of the density of states below the structural transition temperature of 200 K. PMID:12097064

  12. Alignment-to-orientation conversion and nuclear quadrupole resonance D. Budker,1, 2,

    E-print Network

    Budker, Dmitry

    Alignment-to-orientation conversion and nuclear quadrupole resonance D. Budker,1, 2, D. F. Kimball, 2003) The role of alignment-to-orientation conversion (AOC) in nuclear quadrupole resonance (NQR physics. PACS numbers: 76.60.Gv, 32.80.Bx The phenomenon of alignment-to-orientation conver- sion (AOC) [1

  13. NQR study of ternary chalcogenides A3BX3, ABX2, and ABX where A = Cu, Ag, or TI, B = As or Sb, and X = S or Se

    Microsoft Academic Search

    T. J. Bastow; H. J. Whitfield

    1981-01-01

    121Sb, 123Sb, 75As, 63Cu, and 65Cu NQR resonances are reported for CuSbSe2, Tl3SbSe3, Tl3SbS3, Tl3AsS3, Tl3AsSe3, Ag3AsSe3, TlSbS2, CuAsS, AgAsS, and Cu5SbS3I2. Tl3SbSe3 is an incongruently melting compound not observed in an earlier phase-diagram study of the pseudobinary system Tl2Se-Sb2Se3. For isostructural arsenic and antimony chalcogenides the ratio of 75As to 121Sb quadrupole coupling constants is 0.42, and for the

  14. Experimental Test of Complementarity by Nuclear Magnetic Resonance Techniques

    E-print Network

    Xiwen Zhu; Ximing Fang; Xinhua Peng; Mang Feng; Kelin Gao; Fei Du

    2000-11-23

    We have tested complementarity for the ensemble-averaged spin states of nuclei $^{13}$C in the molecule of $^{13}$CHCl$_{3}$ by the use of the spin states of another nuclei $^{1}$H as the path marker. It turns out that the wave-particle duality holds when one merely measures the probability density of quantum states, and that the wave- and particle-like behavior is simultaneously observed with the help of measuring populations and coherence in a single nuclear magnetic resonance(NMR) experiment. Effects of path-marking schemes and causes of the appearance and disappearance of the wave behavior are analysed.

  15. Recent Developments of the Resonance Light Scattering Technique: Technical Evolution, New Probes and Applications

    Microsoft Academic Search

    Jian Ling; Cheng Zhi Huang; Yuan Fang Li; Yun Fei Long; Qie Gen Liao

    2007-01-01

    The resonance light scattering (RLS) technique, scanning simultaneously the excitation and emission monochromators of a common spectrofluorometer to detect enhanced RLS signals, has been used for designating bio?assemblies, aggregation species, and analytical purposes. Herein, we review the reports since our last mini?review in 2003 concerning the new derived RLS techniques, RLS probes, and their applications.

  16. Magnetic resonance imaging gradient coil design by combining optimization techniques with the finite element method

    Microsoft Academic Search

    Funan Shi; Reinhold Ludwig

    1998-01-01

    In this paper, the optimization techniques of complex method, steepest descent, and conjugate gradient are investigated in terms of their convergence behaviors. The conjugate gradient method is then combined with finite element analysis techniques to develop a magnetic resonance imaging (MRI) Gz gradient coil design strategy which maximizes the field linearity within a specified region of interest. It is found

  17. MAGNETIC RESONANCE - ELECTRICAL IMPEDANCE TOMOGRAPHY (MR-EIT): A new technique for high resolution conductivity imaging

    Microsoft Academic Search

    B. Murat EYUBOGLU; Ozlem Birgul; Y. Ziya Ider

    In this study, a new imaging modality for high resolution conductivity imaging is proposed. Both, the surface potentials and the magnetic fields produced by the probing current are measured. Surface potentials are measured by using conventional electrical impedance tomography techniques and high resolution magnetic field measurements are performed by using magnetic resonance imaging techniques. The conductivity distribution is reconstructed iteratively,

  18. Investigation of Wavelet-Based Enhancements to Nuclear Quadrupole Resonance Explosives Detectors

    SciTech Connect

    Kercel, Stephen W.; Dress, William B.; Hibbs, Andrew D.; Barrall, Geoffrey A.

    1998-06-01

    Nuclear Quadrupole Resonance (NQR) is effective for the detection and identification of certain types of explosives such as RDX, PETN and TNT. In explosive detection, the NQR response of certain 14N nuclei present in the crystalline material is probed. The 14N nuclei possess a nuclear quadrupole moment which in the presence of an electric field gradient produces an energy level splitting which may be excited by radio-frequency magnetic fields. Pulsing on the sample with a radio signal of the appropriate frequency produces a transient NQR response which may then be detected. Since the resonant frequency is dependent upon both the quadrupole moment of the 14N nucleus and the nature of the local electric field gradients, it is very compound specific. Under DARPA sponsorship, the authors are using multiresolution methods to investigate the enhancement of operation of NQR explosives detectors used for land mine detection. For this application, NQR processing time must be reduced to less than one second. False alarm responses due to acoustic and piezoelectric ringing must be suppressed. Also, as TNT is the most prevalent explosive found in land mines, NQR detection of TNT must be made practical despite unfavorable relaxation tunes. All three issues require improvement in signal-to-noise ratio, and all would benefit from improved feature extraction. This paper reports some of the insights provided by multiresolution methods that can be used to obtain these improvements. It includes results of multiresolution analysis of experimentally observed NQR signatures for RDX responses and various false alarm signatures in the absence of explosive compounds.

  19. Magnetic correlations in La(2-x)Sr(x)CuO4 from NQR relaxation and specific heat

    NASA Technical Reports Server (NTRS)

    Borsa, F.; Rigamonti, A.

    1990-01-01

    La-139 and Cu-63 Nuclear Quadrupole Resonance (NQR) relaxation measurements in La(2-x)Sr(x)CuO4 for O = to or less than 0.3 and in the temperature range 1.6 + 450 K are analyzed in terms of Cu(++) magnetic correlations and dynamics. It is described how the magnetic correlations that would result from Cu-Cu exchange are reduced by mobile charge defects related to x-doping. A comprehensive picture is given which explains satisfactorily the x and T dependence of the correlation time, of the correlation length and of the Neel temperature T(sub n)(x) as well as being consistent with known electrical resistivity and magnetic susceptibility measurements. It is discussed how, in the superconducting samples, the mobile defects also cause the decrease, for T yields T(sub c)(+) of the hyperfine Cu electron-nucleus effective interaction, leading to the coexistence of quasi-localized, reduced magnetic moments from 3d Cu electrons and mobile oxygen p-hole carriers. The temperature dependence of the effective hyperfine field around the superconducting transition yields an activation energy which could be related to the pairing energy. New specific heat measurements are also presented and discussed in terms of the above picture.

  20. Methods for magnetic resonance analysis using magic angle technique

    DOEpatents

    Hu, Jian Zhi (Richland, WA); Wind, Robert A. (Kennewick, WA); Minard, Kevin R. (Kennewick, WA); Majors, Paul D. (Kennewick, WA)

    2011-11-22

    Methods of performing a magnetic resonance analysis of a biological object are disclosed that include placing the object in a main magnetic field (that has a static field direction) and in a radio frequency field; rotating the object at a frequency of less than about 100 Hz around an axis positioned at an angle of about 54.degree.44' relative to the main magnetic static field direction; pulsing the radio frequency to provide a sequence that includes a phase-corrected magic angle turning pulse segment; and collecting data generated by the pulsed radio frequency. In particular embodiments the method includes pulsing the radio frequency to provide at least two of a spatially selective read pulse, a spatially selective phase pulse, and a spatially selective storage pulse. Further disclosed methods provide pulse sequences that provide extended imaging capabilities, such as chemical shift imaging or multiple-voxel data acquisition.

  1. 35Cl NQR Spectra of several 2,2-bis- p-chlorophenyl chloroethane derivatives

    NASA Astrophysics Data System (ADS)

    Nogaj, B.; Pietrzak, J.; Wielopolska, E.; Schroeder, G.; Jarczewski, A.

    Measurement of NQR line frequency at 77 K have been performed for the following compounds: 1-chloro-2,2-bis-(p-chlorophenyl) ethylene (DDMU), 1,1-dichloro-2,2-bis-(p-chlorophenyl) ethylene (DDE), 1,1-dichloro-2,2-bis-(p-chlorophenyl) ethane (ODD), 1,1,1-trichloro-2,2-bis (p-chlorophenyl) ethane (DDT). An attempt to assign spectrum lines to particular Cl nuclei in a molecule has been made. Molecular and crystallographic inequivalences occurring in these compounds have been considered. Comparison of the NQR and crystallographic data revealed the influence of phenyl rings conformation on electric charge distribution in the studied molecules.

  2. Waveguide-type optical passive ring resonator gyro using frequency modulation spectroscopy technique

    NASA Astrophysics Data System (ADS)

    Liang, Ning; Lijun, Guo; Mei, Kong; Tuoyuan, Chen

    2014-12-01

    This paper reports the experimental results of silica on a silicon ring resonator in a resonator micro optic gyroscope based on the frequency modulation spectroscopy technique by our research group. The ring resonator is composed of a 4 cm diameter silica waveguide. By testing at ? = 1550 nm, the FSR, FWHM and the depth of resonance are 3122 MHz, 103.07 MHz and 0.8 respectively. By using a polarization controller, the resonance curve under the TM mode can be inhibited. The depth of resonance increased from 0.8 to 0.8913, namely the finesse increase from 30.33 to 33.05. In the experiments, there is an acoustic-optical frequency shifter (AOFS) in each light loop. We lock the lasing frequency at the resonance frequency of the silica waveguide ring resonator for the counterclockwise lightwave; the frequency difference between the driving frequencies of the two AOFS is equivalent to the Sagnac frequency difference caused by gyro rotation. Thus, the gyro output is observed. The slope of the linear fit is about 0.330 mV/(°/s) based on the ?900 to 900 kHz equivalent frequency and the gyro dynamic range is ±2.0 × 103 rad/s.

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

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

    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.

  4. Apodization of coupled resonator optical waveguide devices through a longitudinal offset technique

    NASA Astrophysics Data System (ADS)

    Doménech, J. D.; Muńoz, P.; Capmany, J.

    2010-05-01

    In this paper, a novel technique to set the coupling constant between cells of a coupled resonator optical waveguide (CROW) device, in order to tailor the filter response, is presented. It is known that using the same K value for all the couplers produces filtering responses with significant side-lobes for the side-coupled integrated spaced sequence of resonators (SCISSOR) or significant ripples in the pass-band for the direct coupled microrings (CROW). It is also known that the side-lobes/ripples can be reduced, and the pass/reject bands can be made wider, by apodizing the K value of each individual coupler in the structure, starting from a nominal K value (either increasing or decreasing it). This technique consists on changing the effective length of the coupling section by applying a longitudinal offset between the resonators. On the contrary, the conventional techniques are based in the transversal change of the distance between the ring resonators, in steps that are commonly below the current fabrication resolution step (nm scale), leading to strong restrictions in the designs. The technique has been experimentally demonstrated employing a racetrack ring resonator geometry. The proposed longitudinal offset technique allows a more precise control of the coupling and presents an increased robustness against the fabrication limitations, since the needed resolution step is two orders of magnitude higher. Both techniques are compared in terms of the transmission response of CROW devices, under finite fabrication resolution steps. The offset technique presented is sufficient by itself for apodization, and optimized CROW's can be produced with a fixed distance between the rings, solely by changing the offsets.

  5. Experimental study on a resonance mesh coating fabricated using a UV-lithography technique.

    PubMed

    Liu, Yongmeng; Tan, Jiubin

    2013-02-25

    In order to achieve high optical transparency and Ka-band bandpass filtering simultaneously, a resonance mesh coating sample is fabricated using a UV-lithography technique. Optical transmission is measured using an Ocean Optics QE65000 spectrometer. And Ka-band bandpass filtering is measured using an Agilent E8363B PNA series network analyzer. Experimental results indicate that the optical transmission of the resonance mesh coating is 63.4% higher than that of non-meshed Frequency Selective Surfaces (FSS) with equivalent aperture parameters, and the transmittance loss of the coating is lower than 0.21 dB while the coating has a Ka-band resonance frequency of 32 GHz. It can therefore be concluded that the resonance mesh coating can be used as a dual-mode spatial filter to achieve high optical transparency and Ka-band bandpass filtering. PMID:23481956

  6. Surface plasmon resonance reflectance imaging technique for near-field (~100 nm) fluidic characterization

    Microsoft Academic Search

    Kenneth D. Kihm

    2010-01-01

    Surface plasmon resonance (SPR) reflectance imaging technique is devised as a label-free visualization tools to characterize\\u000a near-field (100 nm) fluidic transport properties. The key idea is that the SPR reflectance intensity varies with the near-field\\u000a refractive index (RI) of the test fluid, which in turn depends on the micro\\/nano-fluidic scalar properties, such as concentrations,\\u000a temperatures, and phases. The SPR sensor techniques

  7. CORDIC algorithm based digital detection technique applied in resonator fiber optic gyroscope

    NASA Astrophysics Data System (ADS)

    Yang, Zhihuai; Jin, Xiaojun; Ma, Huilian; Jin, Zhonghe

    2009-06-01

    A digital detection technique based on the coordinate rotation digital computer (CORDIC) algorithm is proposed for a resonator fiber optic gyroscope (R-FOG). It makes the generation of modulation signal, synchronous demodulation and signal processing in R-FOG to be realized in a single field programmable gate array (FPGA). The frequency synthesis and synchronous detection techniques based on the CORDIC algorithm have been analyzed and designed firstly. The experimental results indicate that the precision of the detection circuit satisfies the requirements for the closed-loop feedback in R-FOG system. The frequency of the laser is locked to the resonance frequency of the fiber ring resonator stably and the open-loop gyro output signal is observed successfully. The dynamic range and the bias drift of the R-FOG are ±1.91 rad/s and 0.005 rad/s over 10 s, respectively.

  8. Photooxidation of Chlorins by Quinones Studied by Nuclear Magnetic Resonance Techniques

    Microsoft Academic Search

    Angelo A. Lamola; Marcia L. Manion; Heinz D. Roth; Gordon Tollin

    1975-01-01

    The reactions of photo-excited chlorophylls and pheophytins with quinones have been investigated by nuclear magnetic resonance techniques. In slightly alkaline solutions the quinone signals showed line broadening which is explained by degenerate electron transfer between semiquinone radical ions and their benzoquinone parents. In neutral solutions, chemically induced dynamic nuclear polarization was observed which is ascribed to the pair, chlorophyll cation-semiquinone

  9. A new magnetoelastic resonance based technique to determine magnetomechanical parameters of

    E-print Network

    Paris-Sud XI, Université de

    A new magnetoelastic resonance based technique to determine magnetomechanical parameters the lack of long range order, these figures making them ideal candidates for magnetoelastic applications of magnetoelastic properties. In addition, this method as well as that based on the capacitance effect does

  10. An accurate frequency measuring technique using paramagnetic resonance phenomena in the X-band region

    Microsoft Academic Search

    P. Crandell

    1958-01-01

    This paper presents a method of measuring frequency in the microwave region by comparing it to a very stable low frequency standard. The technique described here was used to calibrate a cavity wavemeter for an experiment in microwave spectroscopy. The calibration procedure is based on the use of electron and nuclear resonances as they are observed in the presence of

  11. Use of a Resonance Technique to Measure Muscle Activity in Neurotic and Schizophrenic Patients

    Microsoft Academic Search

    JAMES G. L. WILLIAMS

    A resonance technique was used to compare the muscle activity of groups of neu- rotic, schizophrenic, and control subjects matched for age and sex. Measurements were taken with subjects relaxing or experiencing a delayed auditory feedback. A replicated three-way analysis of variance showed the test to be reliable, and the groups were differentiated from each other at better than the

  12. Resonator micro optic gyro with double phase modulation technique using an FPGA-based digital processor

    Microsoft Academic Search

    Huilian Ma; Hui Mao; Yan Chen; Zhonghe Jin

    2011-01-01

    A resonator micro optic gyro (RMOG) with the proposed FPGA-based digital processor is set up. The double phase modulation technique is applied to achieve high total carrier suppression. Rotation tests from +\\/-0.1 °\\/s to +\\/-5 °\\/s are tested, where the processing circuit of RMOG is implemented by the instruments. The rotation test over a range of +\\/-550 °\\/s has been

  13. Computation of resonant frequencies and quality factors of cavities by FDTD technique and Pade approximation

    Microsoft Academic Search

    Wei-Hua Guo; Wei-Jun Li; Yong-Zhen Huang

    2001-01-01

    The finite-difference time domain (FDTD) technique and the Pade approximation with Baker's algorithm are used to calculate the mode frequencies and quality factors of cavities. Comparing with the fast Fourier transformation\\/Pade method, we find that the Pade approximation and the Baker's algorithm can obtain exact resonant frequencies and quality factors based on a much shorter time record of the FDTD

  14. (14) N nuclear quadrupole resonance study of piroxicam: confirmation of new polymorphic form v.

    PubMed

    Lavri?, Zoran; Pirnat, Janez; Lužnik, Janko; Puc, Uroš; Trontelj, Zvonko; Sr?i?, Stane

    2015-06-01

    A new polymorphic crystal form of piroxicam was discovered while preparing crystalline samples of piroxicam for (14) N nuclear quadrupole resonance (NQR) analysis. The new crystal form, designated as V, was prepared by evaporative recrystallization from dichloromethane. Three known polymorphic forms (I, II, and III) were also prepared. Our aim was to apply (14) N NQR to characterize the new polymorphic form of piroxicam and compare the results with those of the other known polymorphic forms. Additional analytical methods used for characterization were X-ray powder diffraction (XRPD), thermal analysis, and vibrational spectroscopy. For the first time, a complete set of nine characteristic (14) N NQR frequencies was found for each prepared polymorph of piroxicam. The consistent set of measured frequencies and calculated characteristic quadrupole parameters found for the new polymorphic form V is a convincing evidence that we are dealing with a new form. The already known piroxicam polymorphic forms were characterized similarly. The XRPD results were in accordance with the conclusions of (14) N NQR analysis. The performed study clearly demonstrates a strong potential of (14) N NQR method to be applied as a highly discriminative spectroscopic analytical tool to characterize polymorphic forms. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 104:1909-1918, 2015. PMID:25776345

  15. Background: Electron Spin Resonance, a Qualitative Introduction There is only one technique available with the demonstrated analytical power and the

    E-print Network

    relationship between the microwave frequency and the field the electron actually experiences. That fieldBackground: Electron Spin Resonance, a Qualitative Introduction There is only one technique scale defects in semiconductor systems: electron spin resonance (ESR). [1-29]. The technique is also

  16. Modeling of Optical Resonators Using Gaussian Beams and Ray Tracing Techniques

    NASA Astrophysics Data System (ADS)

    Ruiz, Liliana; Cantu, Sergio; Quetschke, Volker; Rakhmanov, Malik

    2011-10-01

    One of the main components in the laser stabilization subsystem in the Laser Interferometer Gravitational-Wave Observatory (LIGO) is a triangular ring resonator, which filters out high order Hermite-Gaussian modes in the laser beam. We developed a model to study the optical properties of such resonators and investigate their performance. The propagation of the laser beam is modeled by combining ray tracing techniques with wave optics. The model can be used to analyze various effects due to mirror misalignments and fluctuations of the laser beam pointing.

  17. Resonator micro optic gyro with double phase modulation technique using an FPGA-based digital processor

    NASA Astrophysics Data System (ADS)

    Ma, Huilian; Mao, Hui; Chen, Yan; Jin, Zhonghe

    2011-05-01

    A resonator micro optic gyro (RMOG) with the proposed FPGA-based digital processor is set up. The double phase modulation technique is applied to achieve high total carrier suppression. Rotation tests from +/-0.1 °/s to +/-5 °/s are tested, where the processing circuit of RMOG is implemented by the instruments. The rotation test over a range of +/-550 °/s has been successfully obtained with all the processing circuit implemented in FPGA. To the best of our knowledge, these results are the best results of RMOG ever demonstrated in silica resonator with the ring length as short as 7.9 cm.

  18. A bi-symmetric square wave Zeeman modulator for nuclear quadrupole resonance.

    PubMed

    Mao, D; Petersen, G L; Bray, P J

    1992-11-01

    A simple circuit has been designed to generate a bi-symmetric square wave Zeeman modulation for the detection of nuclear quadrupole resonance. The square waveform not only provides an optimum result among bi-symmetric modulation waveforms, but also allows the observation of the Zeeman perturbed NQR powder pattern without the need for an extra external magnetic field. PMID:1365735

  19. Clinical decision support systems for brain tumor characterization using advanced magnetic resonance imaging techniques

    PubMed Central

    Tsolaki, Evangelia; Kousi, Evanthia; Svolos, Patricia; Kapsalaki, Efthychia; Theodorou, Kyriaki; Kappas, Constastine; Tsougos, Ioannis

    2014-01-01

    In recent years, advanced magnetic resonance imaging (MRI) techniques, such as magnetic resonance spectroscopy, diffusion weighted imaging, diffusion tensor imaging and perfusion weighted imaging have been used in order to resolve demanding diagnostic problems such as brain tumor characterization and grading, as these techniques offer a more detailed and non-invasive evaluation of the area under study. In the last decade a great effort has been made to import and utilize intelligent systems in the so-called clinical decision support systems (CDSS) for automatic processing, classification, evaluation and representation of MRI data in order for advanced MRI techniques to become a part of the clinical routine, since the amount of data from the aforementioned techniques has gradually increased. Hence, the purpose of the current review article is two-fold. The first is to review and evaluate the progress that has been made towards the utilization of CDSS based on data from advanced MRI techniques. The second is to analyze and propose the future work that has to be done, based on the existing problems and challenges, especially taking into account the new imaging techniques and parameters that can be introduced into intelligent systems to significantly improve their diagnostic specificity and clinical application. PMID:24778769

  20. Clinical decision support systems for brain tumor characterization using advanced magnetic resonance imaging techniques.

    PubMed

    Tsolaki, Evangelia; Kousi, Evanthia; Svolos, Patricia; Kapsalaki, Efthychia; Theodorou, Kyriaki; Kappas, Constastine; Tsougos, Ioannis

    2014-04-28

    In recent years, advanced magnetic resonance imaging (MRI) techniques, such as magnetic resonance spectroscopy, diffusion weighted imaging, diffusion tensor imaging and perfusion weighted imaging have been used in order to resolve demanding diagnostic problems such as brain tumor characterization and grading, as these techniques offer a more detailed and non-invasive evaluation of the area under study. In the last decade a great effort has been made to import and utilize intelligent systems in the so-called clinical decision support systems (CDSS) for automatic processing, classification, evaluation and representation of MRI data in order for advanced MRI techniques to become a part of the clinical routine, since the amount of data from the aforementioned techniques has gradually increased. Hence, the purpose of the current review article is two-fold. The first is to review and evaluate the progress that has been made towards the utilization of CDSS based on data from advanced MRI techniques. The second is to analyze and propose the future work that has to be done, based on the existing problems and challenges, especially taking into account the new imaging techniques and parameters that can be introduced into intelligent systems to significantly improve their diagnostic specificity and clinical application. PMID:24778769

  1. Nanoscale imaging of plasmonic hot spots and dark modes with the photothermal-induced resonance technique.

    PubMed

    Lahiri, Basudev; Holland, Glenn; Aksyuk, Vladimir; Centrone, Andrea

    2013-07-10

    The collective oscillation of conduction electrons, responsible for the localized surface plasmon resonances, enables engineering nanomaterials by tuning their optical response from the visible to terahertz as a function of nanostructure size, shape, and environment. While theoretical calculations helped tremendously in understanding plasmonic nanomaterials and optimizing their light matter interaction, only a few experimental techniques are available to study these materials with high spatial resolution. In this work, the photothermal-induced resonance (PTIR) technique is applied for the first time to image the dark plasmonic resonance of gold asymmetric split ring resonators (A-SRRs) in the mid-infrared (IR) spectral region with nanoscale resolution. Additionally, the chemically specific PTIR signal is used to map the local absorption enhancement of poly(methyl methacrylate) coated on A-SRRs, revealing hot spots with local enhancement factors up to ?30 at 100 nm lateral resolution. We argue that PTIR nanoscale characterization will facilitate the engineering and application of plasmonic nanomaterials for mid-IR applications. PMID:23777547

  2. The analysis of demodulation characteristic on the resonant optical gyro using frequency modulation technique

    NASA Astrophysics Data System (ADS)

    Ning, Liang; Guo, Lijun; Fang, Gang; Liu, Cihang

    2015-03-01

    The resonator optic gyro (ROG), which utilizes a resonance frequency change due to the Sagnac effect, is a promising candidate for the next generation inertial rotation sensor. In this paper, we first analyzed the signal detection theory and made the demodulation curve modeling. Second, the ROG demodulation test system is set up using the laser frequency modulation spectroscopy technique. The resonance curve of the resonator is detected by the photodiode (PD) and then demodulated by the LIA. By testing at ?=1550nm, and the free spectral range (FSR), the full width at half maximum (FWHM), the depth and the finesse of resonance are 2191.41MHz, 65.55MHz, 0.9 and 33.43 respectively. Calculated from the demodulation signal, the dynamic range of the gyro is from +2.04×103rad/s to -2.04×103rad/s. The slope K1 of the linear part in the demodulation signal is estimated to be 0.8×10-7V/Hz. A basic agreement between experimental results and theoretical calculated values was achieved.

  3. Extracting Information about the Rotator Cuff from Magnetic Resonance Images Using Deterministic and Random Techniques

    PubMed Central

    De Los Ríos, F. A.; Paluszny, M.

    2015-01-01

    We consider some methods to extract information about the rotator cuff based on magnetic resonance images; the study aims to define an alternative method of display that might facilitate the detection of partial tears in the supraspinatus tendon. Specifically, we are going to use families of ellipsoidal triangular patches to cover the humerus head near the affected area. These patches are going to be textured and displayed with the information of the magnetic resonance images using the trilinear interpolation technique. For the generation of points to texture each patch, we propose a new method that guarantees the uniform distribution of its points using a random statistical method. Its computational cost, defined as the average computing time to generate a fixed number of points, is significantly lower as compared with deterministic and other standard statistical techniques. PMID:25650281

  4. Surface plasmon resonance reflectance imaging technique for near-field (~100 nm) fluidic characterization

    Microsoft Academic Search

    Kenneth D. Kihm

    2009-01-01

    Surface plasmon resonance (SPR) reflectance imaging technique is devised as a label-free visualization tools to characterize near-field (100 nm) fluidic transport properties. The key idea is that the SPR reflectance intensity varies with the near-field refractive index (RI) of the test fluid, which in turn depends on the micro\\/nano-fluidic scalar properties, such as concentrations, temperatures, and phases. The SPR sensor

  5. Automated and precise dielectric measurement systems at millimeter wavelengths using open resonator technique

    Microsoft Academic Search

    Y. F. Gui; W. B. Doul; K. Yin; P. G. Su

    2008-01-01

    As low loss dielectric materials, ZnS, MgAl2O4 and MgF2 have a very important application in the millimeter-wave frequency range. However, there is little information about their dielectric properties in the millimeter-wave regions. To obtain their dielectric properties, an automatic open resonator measurement system at Ka-band is designed and constructed. The method of multi-frequency points measurement with frequency variation technique is

  6. Photoelectron resonance capture ionization (PERCI): A novel technique for the soft-ionization of organic compounds

    Microsoft Academic Search

    Brian W. LaFranchi; Giuseppe A. Petrucci

    2004-01-01

    Photoelectron resonance capture ionization (PERCI) is demonstrated as a sensitive ionization technique involving minimal fragmentation\\u000a of organic molecules. PERCI has been used successfully to softly and efficiently ionize both strongly UV absorbing and non-absorbing\\u000a molecules. Tunable low energy (<1 eV) electrons are generated by focusing a pulsed UV laser on an aluminum photocathode in\\u000a the presence of gas phase analyte.

  7. Resonance light scattering and derived techniques in analytical chemistry: past, present, and future

    Microsoft Academic Search

    Wei Lu; Beatriz S. Fernández Band; Yu Yu; Qin Geng Li; Jing Chuan Shang; Chi Wang; Yan Fang; Rui Tian; Li Ping Zhou; Li Li Sun; Yu Tang; Shu Hua Jing; Wei Huang; Ji Ping Zhang

    2007-01-01

    .  From 1993 to 1995, with a conventional fluorescence spectrophotometer (CFS) (convenient) and working in a synchronous scan\\u000a model (easy-to-use), Pasternack et al. proposed the resonance light-scattering (RLS) technique, to efficiently characterize\\u000a self-assemblies or self-aggregations of chromophores with good electronic coupling. Incident wavelengths were specially considered\\u000a within their absorption envelopes (rather unorthodox), and their amplified signals were observed (good sensitivity and

  8. New magnetic resonance imaging and computed tomography techniques for imaging of acute stroke

    Microsoft Academic Search

    Amie W. Hsia; David C. Tong

    2003-01-01

    With continued advances in acute stroke therapy, the ability to accurately assess the physiologic status of ischemic brain\\u000a tissue and related vascular lesions has become increasingly important. In this review, evidence regarding the use of new magnetic\\u000a resonance imaging and computed tomography techniques to guide thrombolytic therapy, diagnose stroke subtype, and detect acute\\u000a hemorrhage are discussed in order to provide

  9. High-efficiency fuel-cell power inverter with soft-switching resonant technique

    Microsoft Academic Search

    Rong-Jong Wai; Rou-Yong Duan; Jeng-Dao Lee; Li-Wei Liu

    2005-01-01

    In order to reduce the capital and overall operating cost of a fuel-cell system, a high-efficiency fuel-cell power inverter with a simple framework is required. The high-order two-inductance two-capacitance (LLCC) resonant technique is adopted in this study to implement a low-frequency 60-Hz sinewave voltage inverter utilized in the proton exchange membrane fuel-cell (PEMFC) system. The methodology for inverting dc voltage

  10. High efficiency resonance ionization mass spectrometric analysis by external laser cavity enhancement techniques

    SciTech Connect

    Johnson, S.G.; Rios, E.L.; Miller, C.M.; Fearey, B.L.

    1991-01-01

    The demand to measure high dynamic range isotope ratios on small samples with resonance ionization mass spectrometry (RIMS) continues to increase. This paper discusses high ionization efficiency methods which can be applied to continuous wave (cw) RIMS to potentially achieve several tens of percent ionization efficiencies for certain elements. The primary technique under development to achieve this is an external laser cavity which can generate very high circulating laser powers. 12 refs., 3 figs.

  11. Roles of the Sodium-Translocating NADH:Quinone Oxidoreductase (Na+-NQR) on Vibrio cholerae Metabolism, Motility and Osmotic Stress Resistance

    PubMed Central

    Minato, Yusuke; Halang, Petra; Quinn, Matthew J.; Faulkner, Wyatt J.; Aagesen, Alisha M.; Steuber, Julia; Stevens, Jan F.; Häse, Claudia C.

    2014-01-01

    The Na+ translocating NADH:quinone oxidoreductase (Na+-NQR) is a unique respiratory enzyme catalyzing the electron transfer from NADH to quinone coupled with the translocation of sodium ions across the membrane. Typically, Vibrio spp., including Vibrio cholerae, have this enzyme but lack the proton-pumping NADH:ubiquinone oxidoreductase (Complex I). Thus, Na+-NQR should significantly contribute to multiple aspects of V. cholerae physiology; however, no detailed characterization of this aspect has been reported so far. In this study, we broadly investigated the effects of loss of Na+-NQR on V. cholerae physiology by using Phenotype Microarray (Biolog), transcriptome and metabolomics analyses. We found that the V. cholerae ?nqrA-F mutant showed multiple defects in metabolism detected by Phenotype Microarray. Transcriptome analysis revealed that the V. cholerae ?nqrA-F mutant up-regulates 31 genes and down-regulates 55 genes in both early and mid-growth phases. The most up-regulated genes included the cadA and cadB genes, encoding a lysine decarboxylase and a lysine/cadaverine antiporter, respectively. Increased CadAB activity was further suggested by the metabolomics analysis. The down-regulated genes include sialic acid catabolism genes. Metabolomic analysis also suggested increased reductive pathway of TCA cycle and decreased purine metabolism in the V. cholerae ?nqrA-F mutant. Lack of Na+-NQR did not affect any of the Na+ pumping-related phenotypes of V. cholerae suggesting that other secondary Na+ pump(s) can compensate for Na+ pumping activity of Na+-NQR. Overall, our study provides important insights into the contribution of Na+-NQR to V. cholerae physiology. PMID:24811312

  12. Roles of the sodium-translocating NADH:quinone oxidoreductase (Na+-NQR) on vibrio cholerae metabolism, motility and osmotic stress resistance.

    PubMed

    Minato, Yusuke; Fassio, Sara R; Kirkwood, Jay S; Halang, Petra; Quinn, Matthew J; Faulkner, Wyatt J; Aagesen, Alisha M; Steuber, Julia; Stevens, Jan F; Häse, Claudia C

    2014-01-01

    The Na+ translocating NADH:quinone oxidoreductase (Na+-NQR) is a unique respiratory enzyme catalyzing the electron transfer from NADH to quinone coupled with the translocation of sodium ions across the membrane. Typically, Vibrio spp., including Vibrio cholerae, have this enzyme but lack the proton-pumping NADH:ubiquinone oxidoreductase (Complex I). Thus, Na+-NQR should significantly contribute to multiple aspects of V. cholerae physiology; however, no detailed characterization of this aspect has been reported so far. In this study, we broadly investigated the effects of loss of Na+-NQR on V. cholerae physiology by using Phenotype Microarray (Biolog), transcriptome and metabolomics analyses. We found that the V. cholerae ?nqrA-F mutant showed multiple defects in metabolism detected by Phenotype Microarray. Transcriptome analysis revealed that the V. cholerae ?nqrA-F mutant up-regulates 31 genes and down-regulates 55 genes in both early and mid-growth phases. The most up-regulated genes included the cadA and cadB genes, encoding a lysine decarboxylase and a lysine/cadaverine antiporter, respectively. Increased CadAB activity was further suggested by the metabolomics analysis. The down-regulated genes include sialic acid catabolism genes. Metabolomic analysis also suggested increased reductive pathway of TCA cycle and decreased purine metabolism in the V. cholerae ?nqrA-F mutant. Lack of Na+-NQR did not affect any of the Na+ pumping-related phenotypes of V. cholerae suggesting that other secondary Na+ pump(s) can compensate for Na+ pumping activity of Na+-NQR. Overall, our study provides important insights into the contribution of Na+-NQR to V. cholerae physiology. PMID:24811312

  13. Infra-Red Surface-Plasmon-Resonance technique for biological studies

    E-print Network

    V. Lirtsman; M. Golosovsky; D. Davidov

    2007-11-18

    We report on a Surface-Plasmon-Resonance (SPR) technique based on Fourier -Transform - Infra - Red (FTIR) spectrometer. In contrast to the conventional surface plasmon technique, operating at a fixed wavelength and a variable angle of incidence, our setup allows the wavelength and the angle of incidence to be varied simultaneously. We explored the potential of the SPR technique in the infrared for biological studies involving aqueous solutions. Using computer simulations, we found the optimal combination of parameters (incident angle, wavelength) for performing this task. Our experiments with physiologically important glucose concentrations in water and in human plasma verified our computer simulations. Importantly, we demonstrated that the sensitivity of the SPR technique in the infrared range is not lower and in fact is even higher than that for visible light. We emphasize the advantages of infra red SPR for studying glucose and other biological molecules in living cells.

  14. Co-NQR Study on Successive Magnetic Phase under Pressure in Non-centrosymmetric CeCoGe3

    NASA Astrophysics Data System (ADS)

    Inagaki, T.; Matsumura, M.; Mizoo, M.; Kawamura, Y.; Kato, H.; Nishioka, T.

    2012-12-01

    We have performed Co-NQR study to clarify the complex magnetic phases in approaching to the quantum critical point (QCP). The successive transitions at TN2=12 K and TN3=8 K after the ferrimagnetic-like order at TN1=21 K in ambient pressure are confirmed by the spectral changes of Co-NQR However no critical slowing down of the nuclear spin-lattice relaxation rate 1/T1 or the nuclear spin-spin relaxation rate 1/T2 at TN2 and TN3 was observed, suggesting 1st order transitions. In applying pressure, a large spectral change of Co-NQR occurs in relatively low pressure of 0.3 Gpa. The Co-NQR spectrum becomes simple above about 0.7 GPa, consisting of the two Co sites with spectral weight ratio of 2. No successive transitions were observed in 1.5 GPa, indicating that the successive transitions are confined to relatively low pressure region. The extremely slower decrease of the sublattice magnetization than that expected in the mean field approximation is seen in 1.5 GPa.

  15. Frequency-Temperature Compensation Techniques for High-Q Microwave Resonators

    NASA Astrophysics Data System (ADS)

    Hartnett, John G.; Tobar, Michael E.

    Low-noise high-stability resonator oscillators based on high-Q monolithic sapphire ``Whispering Gallery'' (WG)-mode resonators have become important devices for telecommunication, radar and metrological applications. The extremely high quality factor of sapphire, of 2 x10^5 at room temperature, 5 x10^7 at liquid nitrogen temperature and 5 x10^9 at liquid helium temperature has enabled the lowest phase noise and highly frequency-stable oscillators in the microwave regime to be constructed. To create an oscillator with exceptional frequency stability, the resonator must have its frequency-temperature dependence annulled at some temperature, as well as a high quality factor. The Temperature Coefficient of Permittivity (TCP) for sapphire is quite large, at 10-100parts per million/K above 77K. This mechanism allows temperature fluctuations to transform to resonator frequency fluctuations.A number of research groups worldwide have investigated various methods of compensating the TCP of a sapphire dielectric resonator at different temperatures. The usual electromagnetic technique of annulment involves the use of paramagnetic impurities contributing an opposite temperature coefficient of the magnetic susceptibility to the TCP. This technique has only been realized successfully in liquid helium environments. Near 4K the thermal expansion and permittivity effects are small and only small quantities of the paramagnetic ions are necessary to compensate the mode frequency. Compensation is due to impurity ions that were incidentally left over from the manufacturing process.Recently, there has been an effort to dispense with the need for liquid helium and make a compact flywheel oscillator for the new generation of primary frequency standards such as the cesium fountain at the Laboratoire Primaire du Temps et des Fréquences (LPTF), France. To achieve the stability limit imposed by quantum projection noise requires that the local oscillator stability is of the order of 10^-14. Currently work is under way to achieve this goal in space-borne and mobile liquid-nitrogen-cooled systems. The work appears promising and, as at early 2000, the realization of this goal should not be far off.In this contribution we review techniques that cancel the TCP of sapphire and other dielectric resonators. Details of the temperature control system required to achieve current and target frequency stabilities are discussed.

  16. A biofilm microreactor system for simultaneous electrochemical and nuclear magnetic resonance techniques

    SciTech Connect

    Renslow, Ryan S.; Babauta, Jerome T.; Majors, Paul D.; Mehta, Hardeep S.; Ewing, R. James; Ewing, Thomas; Mueller, Karl T.; Beyenal, Haluk

    2014-03-01

    In order to fully understand electrochemically active biofilms and the limitations to their scale-up in industrial biofilm reactors, a complete picture of the microenvironments inside the biofilm is needed. Nuclear magnetic resonance (NMR) techniques are ideally suited for the study of biofilms and for probing their microenvironments because these techniques allow for non-invasive interrogation and in situ monitoring with high resolution. By combining NMR with simultaneous electrochemical techniques, it is possible to sustain and study live electrochemically active biofilms. Here, we introduce a novel biofilm microreactor system that allows for simultaneous electrochemical and NMR techniques (EC-NMR) at the microscale. Microreactors were designed with custom radiofrequency resonator coils, which allowed for NMR measurements of biofilms growing on polarized gold electrodes. For an example application of this system, we grew Geobacter sulfurreducens biofilms. NMR was used to investigate growth media flow velocities, which were compared to simulated laminar flow, and electron donor concentrations inside the biofilms. We use Monte Carlo error analysis to estimate standard deviations of the electron donor concentration measurements within the biofilm. The EC-NMR biofilm microreactor system can ultimately be used to correlate extracellular electron transfer rates with metabolic reactions and explore extracellular electron transfer mechanisms.

  17. Automatic detection of ionospheric Alfvén resonances using signal and image processing techniques

    NASA Astrophysics Data System (ADS)

    Beggan, C. D.

    2014-08-01

    Induction coils permit the measurement of small and very rapid changes of the magnetic field. A new set of induction coils in the UK (at L = 3.2) record magnetic field changes over an effective frequency range of 0.1-40 Hz, encompassing phenomena such as the Schumann resonances, magnetospheric pulsations and ionospheric Alfvén resonances (IARs). The IARs typically manifest themselves as a series of spectral resonance structures (SRSs) within the 1-10 Hz frequency range, usually appearing as fine bands or fringes in spectrogram plots and occurring almost daily during local night-time, disappearing during the daylight hours. The behaviour of the occurrence in frequency (f) and the difference in frequency between fringes (?f) varies throughout the year. In order to quantify the daily, seasonal and annual changes of the SRSs, we developed a new method based on signal and image processing techniques to identify the fringes and to quantify the values of f, ?f and other relevant parameters in the data set. The technique is relatively robust to noise though requires tuning of threshold parameters. We analyse 18 months of induction coil data to demonstrate the utility of the method.

  18. A mutation in Na(+)-NQR uncouples electron flow from Na(+) translocation in the presence of K(+).

    PubMed

    Shea, Michael E; Mezic, Katherine G; Juárez, Oscar; Barquera, Blanca

    2015-01-20

    The sodium-pumping NADH:ubiquinone oxidoreductase (Na(+)-NQR) is a bacterial respiratory enzyme that obtains energy from the redox reaction between NADH and ubiquinone and uses this energy to create an electrochemical Na(+) gradient across the cell membrane. A number of acidic residues in transmembrane helices have been shown to be important for Na(+) translocation. One of these, Asp-397 in the NqrB subunit, is a key residue for Na(+) uptake and binding. In this study, we show that when this residue is replaced with asparagine, the enzyme acquires a new sensitivity to K(+); in the mutant, K(+) both activates the redox reaction and uncouples it from the ion translocation reaction. In the wild-type enzyme, Na(+) (or Li(+)) accelerates turnover while K(+) alone does not activate. In the NqrB-D397N mutant, K(+) accelerates the same internal electron transfer step (2Fe-2S ? FMNC) that is accelerated by Na(+). This is the same step that is inhibited in mutants in which Na(+) uptake is blocked. NqrB-D397N is able to translocate Na(+) and Li(+), but when K(+) is introduced, no ion translocation is observed, regardless of whether Na(+) or Li(+) is present. Thus, this mutant, when it turns over in the presence of K(+), is the first, and currently the only, example of an uncoupled Na(+)-NQR. The fact the redox reaction and ion pumping become decoupled from each other only in the presence of K(+) provides a switch that promises to be a useful experimental tool. PMID:25486106

  19. Oxidative Stress Imaging in Live Animals with Techniques Based on Electron Paramagnetic Resonance

    PubMed Central

    Elas, Martyna; Ichikawa, Kazuhiro; Halpern, Howard J.

    2013-01-01

    Oxidative stress has been the object of considerable biological and biochemical investigation. Quantification has been difficult although the quantitative level of products of biological oxidations in tissues and tissue products has emerged as a widely used technique. The relationship between these products and the amount of oxidative stress is less clear. Imaging oxidative stress with electron paramagnetic resonance related magnetic resonance imaging, while not addressing the specific issue of quantification of initiating events, focuses on the anatomic specific location of the oxidative stress. Moreover, the relative quantification of oxidative stress of one location against another is possible, sharpening our understanding of oxidative stress. This promises to improve our understanding of oxidative stress and its deleterious consequences and enhance our understanding of the effectiveness of interventions to modulate oxidative stress and its consequences. PMID:22348251

  20. Review of pyroelectric thermal energy harvesting and new MEMs based resonant energy conversion techniques

    SciTech Connect

    Hunter, Scott Robert [ORNL; Lavrik, Nickolay V [ORNL; Mostafa, Salwa [ORNL; Rajic, Slobodan [ORNL; Datskos, Panos G [ORNL

    2012-01-01

    Harvesting electrical energy from thermal energy sources using pyroelectric conversion techniques has been under investigation for over 50 years, but it has not received the attention that thermoelectric energy harvesting techniques have during this time period. This lack of interest stems from early studies which found that the energy conversion efficiencies achievable using pyroelectric materials were several times less than those potentially achievable with thermoelectrics. More recent modeling and experimental studies have shown that pyroelectric techniques can be cost competitive with thermoelectrics and, using new temperature cycling techniques, has the potential to be several times as efficient as thermoelectrics under comparable operating conditions. This paper will review the recent history in this field and describe the techniques that are being developed to increase the opportunities for pyroelectric energy harvesting. The development of a new thermal energy harvester concept, based on temperature cycled pyroelectric thermal-to-electrical energy conversion, are also outlined. The approach uses a resonantly driven, pyroelectric capacitive bimorph cantilever structure that can be used to rapidly cycle the temperature in the energy harvester. The device has been modeled using a finite element multi-physics based method, where the effect of the structure material properties and system parameters on the frequency and magnitude of temperature cycling, and the efficiency of energy recycling using the proposed structure, have been modeled. Results show that thermal contact conductance and heat source temperature differences play key roles in dominating the cantilever resonant frequency and efficiency of the energy conversion technique. This paper outlines the modeling, fabrication and testing of cantilever and pyroelectric structures and single element devices that demonstrate the potential of this technology for the development of high efficiency thermal-to-electrical energy conversion devices.

  1. A Second Look at Neutron Resonance Transmission Analysis as a Spent Fuel NDA Technique

    SciTech Connect

    James W .Sterbentz; David L. Chichester

    2011-07-01

    Many different nondestructive analysis techniques are currently being investigated as a part of the United States Department of Energy's Next Generation Safeguards Initiative (NGSI) seeking methods to quantify plutonium in spent fuel. Neutron Resonance Transmission Analysis (NRTA) is one of these techniques. Having first been explored in the mid-1970s for the analysis of individual spent-fuel pins a second look, using advanced simulation and modeling methods, is now underway to investigate the suitability of the NRTA technique for assaying complete spent nuclear fuel assemblies. The technique is similar to neutron time-of-flight methods used for cross-section determinations but operates over only the narrow 0.1-20 eV range where strong, distinguishable resonances exist for both the plutonium (239, 240, 241,242Pu) and uranium (235,236,238U) isotopes of interest in spent fuel. Additionally, in this energy range resonances exists for six important fission products (99Tc, 103Rh, 131Xe, 133Cs, 145Nd, and 152Sm) which provide additional information to support spent fuel plutonium assay determinations. Initial modeling shows excellent agreement with previously published experimental data for measurements of individual spent-fuel pins where plutonium assays were demonstrated to have a precision of 2-4%. Within the simulation and modeling analyses of this project scoping studies have explored fourteen different aspects of the technique including the neutron source, drift tube configurations, and gross neutron transmission as well as the impacts of fuel burn up, cooling time, and fission-product interferences. These results show that NRTA may be a very capable experimental technique for spent-fuel assay measurements. The results suggest sufficient transmission strength and signal differentiability is possible for assays through up to 8 pins. For an 8-pin assay (looking at an assembly diagonally), 64% of the pins in a typical 17 ? 17 array of a pressurized water reactor fuel assembly can be part of a complete transmission assay measurement with high precision. Analysis of rows with up to 12 pins may also be feasible but with diminished precision. Preliminary data analysis of an NRTA simulation has demonstrated the simplicity of the technique.

  2. Thickness-induced resonance-based complex permittivity measurement technique for barium strontium titanate ceramics at microwave frequency.

    PubMed

    Xia, Song; Xu, Zhuo; Wei, Xiaoyong

    2009-11-01

    Thickness-induced resonance would be the major factor of uncertainty for complex permittivity measurement by using transmission/reflection method when the thickness of sample is several integer multiples of the half wavelength. A new technique for complex permittivity measurement was presented in this paper using the thickness-induced resonance for barium strontium titanate (BST) ceramics at microwave frequency. Simulated and experimental results show that there are some resonance peaks on the transmittance versus frequency curve and the complex permittivity can be calculated from the resonance. PMID:19947747

  3. Development of techniques in magnetic resonance and structural studies of the prion protein

    SciTech Connect

    Bitter, Hans-Marcus L.

    2000-07-01

    Magnetic resonance is the most powerful analytical tool used by chemists today. Its applications range from determining structures of large biomolecules to imaging of human brains. Nevertheless, magnetic resonance remains a relatively young field, in which many techniques are currently being developed that have broad applications. In this dissertation, two new techniques are presented, one that enables the determination of torsion angles in solid-state peptides and proteins, and another that involves imaging of heterogenous materials at ultra-low magnetic fields. In addition, structural studies of the prion protein via solid-state NMR are described. More specifically, work is presented in which the dependence of chemical shifts on local molecular structure is used to predict chemical shift tensors in solid-state peptides with theoretical ab initio surfaces. These predictions are then used to determine the backbone dihedral angles in peptides. This method utilizes the theoretical chemicalshift tensors and experimentally determined chemical-shift anisotropies (CSAs) to predict the backbone and side chain torsion angles in alanine, leucine, and valine residues. Additionally, structural studies of prion protein fragments are described in which conformationally-dependent chemical-shift measurements were made to gain insight into the structural differences between the various conformational states of the prion protein. These studies are of biological and pathological interest since conformational changes in the prion protein are believed to cause prion diseases. Finally, an ultra-low field magnetic resonance imaging technique is described that enables imaging and characterization of heterogeneous and porous media. The notion of imaging gases at ultra-low fields would appear to be very difficult due to the prohibitively low polarization and spin densities as well as the low sensitivities of conventional Faraday coil detectors. However, Chapter 5 describes how gas imaging at ultra-low fields is realized by incorporating the high sensitivities of a dc superconducting quantum interference device (SQUID) with the high polarizations attainable through optica11y pumping {sup 129}Xe gas.

  4. Sodium and potassium salts of dichloroisocyanuric acid and their hydrates as antimicrobials agents studied by 35Cl-NQR spectroscopy and DFT calculations

    Microsoft Academic Search

    A. Walczak; B. Brycki; M. Kaczmarek; O. Kh. Poleshchuk; M. Ostafin; B. Nogaj

    2006-01-01

    The electronic structure of dichloroisocyanuric acid derivatives was analysed by 35Cl-NQR spectroscopy and DFT calculations. Here we concentrate our attention on three different factors: type of metallic substituent (sodium and potassium), temperature of the sample (liquid nitrogen and room) and degree of hydration (an amount of water molecules attached to analysed compounds). In particular, all the variations in 35Cl-NQR frequencies

  5. Testing isotropy of the universe using the Ramsey resonance technique on ultracold neutron spins

    NASA Astrophysics Data System (ADS)

    Altarev, I.; Ban, G.; Bison, G.; Bodek, K.; Daum, M.; Fertl, M.; Fierlinger, P.; Franke, B.; Gutsmiedl, E.; Heil, W.; Henneck, R.; Horras, M.; Khomutov, N.; Kirch, K.; Kistryn, S.; Kraft, A.; Knecht, A.; Knowles, P.; Kozela, A.; Lauer, T.; Lauss, B.; Lefort, T.; Lemičre, Y.; Mtchedlishvili, A.; Naviliat-Cuncic, O.; Pazgalev, A.; Petzoldt, G.; Piegsa, F. M.; Pierre, E.; Pignol, G.; Quéméner, G.; Rebetez, M.; Rebreyend, D.; Roccia, S.; Schmidt-Wellenburg, P.; Severijns, N.; Sobolev, Yu.; Weis, A.; Zejma, J.; Zenner, J.; Zsigmond, G.

    2011-06-01

    Physics at the Planck scale could be revealed by looking for tiny violations of fundamental symmetries in low energy experiments. In 2008, a sensitive test of the isotropy of the universe has been performed with stored ultracold neutrons (UCN), this is the first clock-comparison experiment performed with free neutrons. During several days we monitored the Larmor frequency of neutron spins in a weak magnetic field using the Ramsey resonance technique. A nonzero cosmic axial field, violating rotational symmetry, would induce a daily variation of the precession frequency. Our null result constitutes one of the most stringent tests of Lorentz invariance to date.

  6. Magnetic resonance imaging of multiple sclerosis: a study of pulse-technique efficacy

    SciTech Connect

    Runge, V.M.; Price, A.C.; Kirshner, H.S.; Allen, J.H.; Partain, C.L.; James, A.E. Jr.

    1984-11-01

    Forty-two patients with the clinical diagnosis of multiple sclerosis were examined by proton magnetic resonance imaging (MRI) at 0.5 T. An extensive protocol was used to facilitate a comparison of the efficacy of different pulse techniques. Results were also compared in 39 cases with high-resolution x-ray computed tomography (CT). MRI revealed characteristic abnormalities in each case, whereas CT was positive in only 15 of 33 patients. Cerebral abnormalities were best shown with the T2-weighted spin-echo sequence: brainstem lesions were best defined on the inversion-recovery sequence.

  7. Development of a dispersive read-out technique for quantum measurements of nanomechanical resonators

    NASA Astrophysics Data System (ADS)

    Rouxinol, Francisco; Lahaye, Matt

    2012-02-01

    The development of techniques to observe non-classical behavior of micro- and nano- scale mechanical structures has received considerable attention in recent years because of the potential to use these systems for fundamental studies of quantum mechanics as well as their possible role as new technologies for applications ranging from the sensing of weak forces to quantum communication. One important route for observing such behavior is the coupling of micro- and nanomechanical resonators with superconducting qubits. Under certain conditions, qubit-coupled mechanical devices are formally analogous to Jaynes-Cummings systems which have been used in fields such as cavity QED for explorations of matter-radiation interactions and the quantum nature of light. Correspondingly, experiments in the last couple of years have begun to develop superconducting qubits as tools to manipulate and measure quantum states of mechanics. In this talk, we will discuss our efforts to integrate charge-type superconducting qubits as elements for dispersive (non-resonant) read-out and control of nanomechanical resonators, including preliminary system design and the prospects of implementing this system for read-out of the number-state statistics of nanomechanical modes.

  8. High-frequency mode conversion technique for stiff lesion detection with magnetic resonance elastography (MRE).

    PubMed

    Mariappan, Yogesh K; Glaser, Kevin J; Manduca, Armando; Romano, Anthony J; Venkatesh, Sudhakar K; Yin, Meng; Ehman, Richard L

    2009-12-01

    A novel imaging technique is described in which the mode conversion of longitudinal waves is used for the qualitative detection of stiff lesions within soft tissue using magnetic resonance elastography (MRE) methods. Due to the viscoelastic nature of tissue, high-frequency shear waves attenuate rapidly in soft tissues but much less in stiff tissues. By introducing minimally-attenuating longitudinal waves at a significantly high frequency into tissue, shear waves produced at interfaces by mode conversion will be detectable in stiff regions, but will be significantly attenuated and thus not detectable in the surrounding soft tissue. This contrast can be used to detect the presence of stiff tissue. The proposed technique is shown to readily depict hard regions (mimicking tumors) present in tissue-simulating phantoms and ex vivo breast tissue. In vivo feasibility is demonstrated on a patient with liver metastases in whom the tumors are readily distinguished. Preliminary evidence also suggests that quantitative stiffness measurements of stiff regions obtained with this technique are more accurate than those from conventional MRE because of the short shear wavelengths. This rapid, qualitative technique may lend itself to applications in which the localization of stiff, suspicious neoplasms is coupled with more sensitive techniques for thorough characterization. PMID:19859936

  9. Phase-stepping technique for highly sensitive microscopic surface plasmon resonance biosensor.

    PubMed

    Zhang, Chonglei; Wang, Rong; Wang, Yijia; Zhu, Siwei; Min, Changjun; Yuan, X-C

    2014-02-10

    In this paper, the phase-stepping technique is applied to improve a phase-sensitive surface plasmon resonance biosensor based on differential interferometry between focused radially polarized and azimuthally polarized cylindrical vector beams. Detailed analysis is presented for the phase-stepping method, and the least squares unwrapping algorithm is employed to detect the phase distribution in correspondence to the refractive index of sample. Benefiting from the phase-stepping technique, both the measurement speed and sensitivity are improved significantly. The proposed sensor maintains high sensitivity of 9.4×10-7??RIU/1° and a wide dynamic range of 0.35 RIU simultaneously. Furthermore, the real-time binding reaction process of bovine serum albumin with antibody is monitored to verify the system for potential biological applications. PMID:24663261

  10. Magnetic Resonance Techniques Applied to the Diagnosis and Treatment of Parkinson’s Disease

    PubMed Central

    de Celis Alonso, Benito; Hidalgo-Tobón, Silvia S.; Menéndez-González, Manuel; Salas-Pacheco, José; Arias-Carrión, Oscar

    2015-01-01

    Parkinson’s disease (PD) affects at least 10 million people worldwide. It is a neurodegenerative disease, which is currently diagnosed by neurological examination. No neuroimaging investigation or blood biomarker is available to aid diagnosis and prognosis. Most effort toward diagnosis using magnetic resonance (MR) has been focused on the use of structural/anatomical neuroimaging and diffusion tensor imaging (DTI). However, deep brain stimulation, a current strategy for treating PD, is guided by MR imaging (MRI). For clinical prognosis, diagnosis, and follow-up investigations, blood oxygen level-dependent MRI, DTI, spectroscopy, and transcranial magnetic stimulation have been used. These techniques represent the state of the art in the last 5?years. Here, we focus on MR techniques for the diagnosis and treatment of Parkinson’s disease.

  11. Quantitative Analysis of Hydration Using Nitrogen-14 Nuclear Quadrupole Resonance.

    PubMed

    Gregorovi?, Alan

    2015-07-01

    Hydration is a quite common process in pharmaceutical solids. Sometimes it is desirable, as it stabilizes the crystal structure; in other cases it is unwanted, as it changes the physical and chemical properties of drugs. We here use (14)N NQR spectroscopy to quantitatively analyze hydration of a model compound, 5-aminotetrazole. (14)N NQR has some great advantages compared to other routinely used techniques to study hydration, like a very simple spectrum, single point calibration, and no need for special sample preparation, but the method's great disadvantage is a rather small sensitivity. Nevertheless, here we demonstrate that (14)N NQR, although being significantly less sensitive than XRD, NIR, and also (35)Cl NQR, is still capable of providing excellent quantitative accuracies. We can achieve errors <1% of the total amount, provided good temperature stabilization is implemented, which then allows long experimental times. We also present results obtained with a SLSE pulse sequence, which is a less robust approach but allows the use of much shorter measuring times (?200×) and could be used for quantitative real time monitoring of hydration or dehydration. PMID:26008906

  12. NQR and ? SR in Diluted Two-Dimensional S=1/2 Heisenberg Antiferromagnets

    NASA Astrophysics Data System (ADS)

    Carretta, P.; Rigamonti, A.; Todeschini, E.; Malavasi, L.

    2003-02-01

    139La NQR spectra and relaxation and ? SR precessional frequencies in La2Cu1-xMxO4 (for M = Zn and Mg) are reported in order to study the effect of spin dilution in the planar quantum Heisenberg antiferromagnet (2DQHAF) La2CuO4. The behavior of the spin stiffness ? s(x) and of the in-plane correlation length ? 2D(x,T), of the sublattice magnetization and of the Néel temperature, for a dilution approaching the percolation threshold depart sizeably from the ones expected in dilution-like models. In spite of the marked reduction of ? s the transition to the ordered state occurs at a temperature, where ? 2D(x,TN) reaches a value close to the one in undoped 2DQHAF.

  13. Nuclear quadrupole resonance of explosives: Simultaneous detection of RDX and PETN in semtex

    Microsoft Academic Search

    R. I. Jenkinson; J. M. Bradley; G. N. Shilstone

    2004-01-01

    We have used nuclear quadrupole resonance (NQR) for the detection of14N in explosives and introduce a new method for the simultaneous detection of the explosives cyclotrimethylene trinitramine\\u000a (RDX) and pentaerythritol tetranitrate (PETN). We have developed an interleaved pulse sequence, which provides efficient excitation\\u000a of both RDX and PETN, to drive a solenoid coil that is doubly resonant at 3.41 and

  14. IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, VOL. 39, NO. 12, DECEMBER 1991 A Scattering-Type Transverse Resonance

    E-print Network

    Bornemann, Jens

    . IEEE Log Number 9102781. conductor-backing effects [6], [7], mode conversion [8], dense packaging [9IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, VOL. 39, NO. 12, DECEMBER 1991 2083 A Scattering-Type Transverse Resonance Technique for the Calculation of (M) MIC Transmission Line

  15. Magnetic resonance imaging of the thorax: techniques, current applications, and future directions.

    PubMed

    Spritzer, C; Gamsu, G; Sostman, H D

    1989-04-01

    Magnetic resonance imaging (MRI) has been used extensively to evaluate the central nervous and musculoskeletal systems. MRI provides excellent contrast between normal and pathologic tissues, identifies vascular structures without the need of intravenous contrast, and is able to image in multiple planes. Until recently, physiologic motion produced artifacts that markedly limited the use of MRI in the thorax. However, with the advent of cardiac gating and respiratory motion compensation, diagnostic images can now be readily acquired. The ability to distinguish between flowing blood and adjacent tissue allows for the detection of aortic aneurysms and dissections. Prominent vessels may be differentiated from hilar adenopathy without the use of contrast agents. Preliminary experience suggests MRI may be useful in assessing central pulmonary emboli and mediastinal venous obstruction. The ready identification of flow combined with the multiplanar capability of MRI provide a means of assessing congenital abnormalities and other anatomic information. Fast scan techniques provide a dynamic means of assessing cardiac function and are sensitive to valvular stenosis and insufficiency. Combined with spin-echo techniques, areas of myocardial infarction and focal wall motion abnormalities can be detected. Currently, MRI has little application in the assessment of pulmonary nodules, bronchogenic cancer, and diffuse parenchymal disease. Sagittal MR images may more clearly show tumor extension into the axilla, brachial plexus, and spinal canal in patients with superior sulcus neoplasms. Future applications may include faster imaging techniques, blood flow measurement, detection of thrombus using phase sensitive techniques, regional perfusion, and assessment of cellular energy metabolism. PMID:2654407

  16. Magnetic resonance imaging: Review of imaging techniques and overview of liver imaging

    PubMed Central

    Maniam, Santhi; Szklaruk, Janio

    2010-01-01

    Magnetic resonance imaging (MRI) of the liver is slowly transitioning from a problem solving imaging modality to a first line imaging modality for many diseases of the liver. The well established advantages of MRI over other cross sectional imaging modalities may be the basis for this transition. Technological advancements in MRI that focus on producing high quality images and fast imaging, increasing diagnostic accuracy and developing newer function-specific contrast agents are essential in ensuring that MRI succeeds as a first line imaging modality. Newer imaging techniques, such as parallel imaging, are widely utilized to shorten scanning time. Diffusion weighted echo planar imaging, an adaptation from neuroimaging, is fast becoming a routine part of the MRI liver protocol to improve lesion detection and characterization of focal liver lesions. Contrast enhanced dynamic T1 weighted imaging is crucial in complete evaluation of diseases and the merit of this dynamic imaging relies heavily on the appropriate timing of the contrast injection. Newer techniques that include fluoro-triggered contrast enhanced MRI, an adaptation from 3D MRA imaging, are utilized to achieve good bolus timing that will allow for optimum scanning. For accurate interpretation of liver diseases, good understanding of the newer imaging techniques and familiarity with typical imaging features of liver diseases are essential. In this review, MR sequences for a time efficient liver MRI protocol utilizing newer imaging techniques are discussed and an overview of imaging features of selected common focal and diffuse liver diseases are presented. PMID:21160685

  17. Magnetic resonance urography for the assessment of potential renal donors: comparison of the RARE technique with a low-dose gadolinium-enhanced magnetic resonance urography technique in the absence of pharmacological and mechanical intervention

    Microsoft Academic Search

    Klaus D. Hagspiel; Sabah Butty; Kiran R. Nandalur; Eric A. Bissonette; Ming-Chen Paul Shih; Daniel A. Leung; J. Fritz Angle; David J. Spinosa; Alan H. Matsumoto; Hossam Ahmed; Hilary Sanfey; Ross B. Isaacs; Robert G. Sawyer; Timothy L. Pruett

    2005-01-01

    The aim of this study was to determine whether magnetic resonance urography without pharmacological (diuretic) stimulation and mechanical compression allows conclusive evaluation of the urinary system in potential renal donors. In 28 consecutive patients magnetic resonance urography (MRU) was performed on a 1.5-T system. Two techniques, rapid acquisition with relaxation enhancement (RARE) and a gadolinium (Gd)-enhanced 3D fast low angle

  18. Thickness-induced resonance-based complex permittivity measurement technique for barium strontium titanate ceramics at microwave frequency

    Microsoft Academic Search

    Song Xia; Zhuo Xu; Xiaoyong Wei

    2009-01-01

    Thickness-induced resonance would be the major factor of uncertainty for complex permittivity measurement by using transmission\\/reflection method when the thickness of sample is several integer multiples of the half wavelength. A new technique for complex permittivity measurement was presented in this paper using the thickness-induced resonance for barium strontium titanate (BST) ceramics at microwave frequency. Simulated and experimental results show

  19. Implant stability evaluation by resonance frequency analysis in the fit lock technique. A clinical study

    PubMed Central

    Falisi, Giovanni; Galli, Massimo; Velasquez, Pedro Vittorini; Rivera, Juan Carlos Gallegos; Di Paolo, Carlo

    2013-01-01

    Summary Surgical procedures for the application of implants in the lateral-superior sectors are affected by the availability of the residual bone. When this condition is lower than 5 mm it is recommended that techniques involving two therapeutic phases, a reconstructive and an applicative one, as reported in the international literature, are adopted. The authors propose here a new method with the potential to apply implants simultaneously with the reconstructive phase. The aim of this longitudinal retrospective study was to evaluate the stability of implants applied with the fit lock technique in the upper maxillarys in us with bone availability lower than 4 mm by measuring resonance frequency at different follow-up periods The seme as urements, carried out on 30 implants, were analysed with specific statistical procedures. The results indicate that the stability of the implants inserted with the fit lock method increases progressively over time in a statistically significant manner. The stability recorded after one year from the insertion (ISQ T2) is significantly higher than that recorded after six months (ISQ T1), and this is significantly higher than that recorded at the time of implant placement (ISQ T0). The implants inserted in the maxillary zones with scarce bone availability and applied with this technique showed a similar stability as reported with other techniques. In light of the results, the authors confirm that the primary stability represents the basic requirement to guarantee a correct healing of the implant and demonstrate that the fit lock technique also all ows reaching this condition when bone availability is minimal. PMID:23991271

  20. Surface plasmon resonance reflectance imaging technique for near-field (~100 nm) fluidic characterization

    NASA Astrophysics Data System (ADS)

    Kihm, Kenneth D.

    2009-07-01

    Surface plasmon resonance (SPR) reflectance imaging technique is devised as a label-free visualization tools to characterize near-field (100 nm) fluidic transport properties. The key idea is that the SPR reflectance intensity varies with the near-field refractive index (RI) of the test fluid, which in turn depends on the micro/nano-fluidic scalar properties, such as concentrations, temperatures, and phases. The SPR sensor techniques have been widely used in many different areas, particularly in the biomedical and biophysical societies. While flow visualization techniques based on RI detection have been extensively well documented (Merzkirch 1987), the use of SPR imaging for fluidic applications has been introduced only recently since the author’s group presented a series of related studies in the past few years. The primary goal of this review article is two-fold: (1) Introduction of the working principles of the SPR imaging as a fluidic sensor, and (2) Presentation of example measurement applications for various fluidic scalar properties using the SPR imaging sensor technique. Section 1 summarizes the history and the basic principle of SPR by focusing on the Kretschmann’s theory and Sect. 2 describes the laboratory SPR imaging system specifically designed for fluidic applications. Section 3 presents the optical and material properties that affect the SPR measurement capabilities and sensitivity. Section 4 presents example applications of the implemented SPR for different near-field characterization problems, including (1) micromixing concentration field, (2) convective/diffusion of salinity distributions, (3) full-field thermometry, and (4) fingerprinting of crystallized nanofluidic self assembly. Sections 5 and 6 discuss the spatial measurement resolutions of the SPR imaging technique and the overall measurement sensitivities, respectively. Section 7 presents a few suggestions to further enhance the SPR measurement accuracy particularly for near-field fluidic characterization.

  1. Three-dimensional electron paramagnetic resonance imaging technique for mapping porosity in ceramics

    SciTech Connect

    Kordas, G.; Kang, Y.H. (Science and Technology Center for Cement, Dept. of Materials Science and Engineering, Ceramics Div., Univ. of Illinois at Urbana-Champaign, Urbana, IL (US))

    1991-04-01

    This paper reports on a three-dimensional (3D) electron paramagnetic resonance imaging (EPRI) method which was developed to probe the structure and size of pores in ceramic materials. The imaging device that was added to the EPR instrument consisted of a computer-controlled current source and magnetic field gradient. This add-on facility was tested using a well-defined diphenlpicrylhydrazzyl phantom sample. Pumice was then used to demonstrate the potential of the technique. This stone was immersed in a 0.5 mm {sup 15}N-substituted per-deutereted tempone water solution to fill the pores with spin labels. Images were reconstructed using a filtered back-projection technique. A two-dimensional (2D) imaging plane was constructed by collecting 33 projection planes over 180 {degrees}. A 3D image was derived from 22 planes each constructed by 22 projections. At present, the facility allows a resolution of 69 and 46 {mu}m for 2D and 3D imaging, respectively. Advancements of the imaging apparatus, software, and line width of the spin labels will be needed to enhance the resolution of this technique.

  2. Resonance

    NSDL National Science Digital Library

    Kuphaldt, Tony R.

    All About Circuits is a website that â??provides a series of online textbooks covering electricity and electronics.â?ť 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).

  3. NQR study of local structures and cooling rate dependent superconductivity in La sub 2 CuO sub 4+. delta

    SciTech Connect

    Reyes, A.P.; Ahrens, E.T.; Hammel, P.C.; Heffner, R.H.; Thompson, J.D.; Canfield, P.C.; Fisk, Z. (Los Alamos National Lab., NM (United States)); Schirber, J.E. (Sandia National Labs., Albuquerque, NM (United States))

    1992-01-01

    Structural properties of oxygen-annealed polycrystals of La{sub 2}CuO{sub 4 + {delta}} ({delta}{approximately}0.03) have been studied using {sup 139}La NQR spectroscopy. Superconducting critical temperatures were found to depend on the rate of cooling through a narrow temperature range at about 195K. Preliminary analysis of the {sup 139}La NQR spectra suggest that the oxygen-rich phase-separated region is composed of two structurally distinct phases, both of which are metallic and super-conducting. One phase has a structure closely related to the stoichiometric oxygen-poor compound. The second shows a considerable amount of apical oxygen disorder, a large shift in NQR frequency {nu}{sub Q}, and a volume fraction which increases with cooling rate. The formation of the second phase below {minus}200K is indicative of the freezing Of CuO{sub 6} octahedral tilting. Abrupt shifts in {nu}{sub Q} above {Tc} were also observed for both phases, suggestive of a local structural anomaly or charge transfer to the Cu-O plane.

  4. Measurement of the corpus callosum using magnetic resonance imaging: analyses of methods and techniques.

    PubMed

    Dorion, A A; Capron, C; Duyme, M

    2001-06-01

    Since the first postmortem report of sex-related differences in the size of the human corpus callosum, a number of studies on sex differences have been published, but results conflicted. The aim of this review was not to assess the possible existence and magnitude of sex variations in the size of the corpus callosum but to analyze methodological differences in several studies using Magnetic Resonance Imaging to investigate the sexual dimorphism in the size of the corpus callosum. Methodological problems arise at several steps of the method: sampling, imagery techniques, and measurements. Moreover, the means of callosal areas obtained by the nine reported studies are significantly different. The hypothesis that methodoiogical differences could explain these differences is supported by statistical results. A common method for investigating sex-related differences in callosal morphology appears necessary to resolve the question of a real sexual dimorphism of the corpus callosum and its subregions. PMID:11565916

  5. Evaluation of Possible Nuclear Magnetic Resonance Diagnostic Techniques for Tokamak Experiments

    SciTech Connect

    S.J. Zweben; T.W. Kornack; D. Majeski; G. Schilling; C.H. Skinner; R. Wilson

    2002-08-05

    Potential applications of nuclear magnetic resonance (NMR) diagnostic techniques to tokamak experiments are evaluated. NMR frequencies for hydrogen isotopes and low-Z nuclei in such experiments are in the frequency range approximately equal to 20-200 MHz, so existing RF [radio-frequency] antennas could be used to rotate the spin polarization and to make the NMR measurements. Our tentative conclusion is that such measurements are possible if highly spin polarized H or (superscript)3He gas sources (which exist) are used to fuel these plasmas. In addition, NMR measurements of the surface layers of the first wall (without plasma) may also be possible, e.g., to evaluate the inventory of tritium inside the vessel.

  6. Open-loop operation experiments in a resonator fiber-optic gyro using the phase modulation spectroscopy technique.

    PubMed

    Zhang, Xu-lin; Ma, Hui-Iian; Jin, Zhong-he; Ding, Chun

    2006-11-01

    A detection system in the resonator fiber-optic gyro is set up by the phase modulation (PM) spectroscopy technique. The slope of the demodulated curve near the resonant point is found to affect the ultimate sensitivity of the gyro. To maximize the demodulated signal slope, the modulation frequency and index are optimized by the expansion of the Bessel function and optical field overlapping method. Using different PM frequencies for the light waves, the open-loop gyro output signal is observed. The modulation frequency in this PM technique is limited only by the cutoff frequency of the LiNbO3 phase modulators, which can reach several gigahertz. This detection technique and system can be applied to the resonator micro-optic gyro with a less than 10 cm long integrated optical ring. PMID:17068533

  7. Further Evaluation of the Neutron Resonance Transmission Analysis (NRTA) Technique for Assaying Plutonium in Spent Fuel

    SciTech Connect

    J. W. Sterbentz; D. L. Chichester

    2011-09-01

    This is an end-of-year report (Fiscal Year (FY) 2011) for the second year of effort on a project funded by the National Nuclear Security Administration's Office of Nuclear Safeguards (NA-241). The goal of this project is to investigate the feasibility of using Neutron Resonance Transmission Analysis (NRTA) to assay plutonium in commercial light-water-reactor spent fuel. This project is part of a larger research effort within the Next-Generation Safeguards Initiative (NGSI) to evaluate methods for assaying plutonium in spent fuel, the Plutonium Assay Challenge. The second-year goals for this project included: (1) assessing the neutron source strength needed for the NRTA technique, (2) estimating count times, (3) assessing the effect of temperature on the transmitted signal, (4) estimating plutonium content in a spent fuel assembly, (5) providing a preliminary assessment of the neutron detectors, and (6) documenting this work in an end of the year report (this report). Research teams at Los Alamos National Laboratory (LANL), Lawrence Berkeley National Laboratory (LBNL), Pacific Northwest National Laboratory (PNNL), and at several universities are also working to investigate plutonium assay methods for spent-fuel safeguards. While the NRTA technique is well proven in the scientific literature for assaying individual spent fuel pins, it is a newcomer to the current NGSI efforts studying Pu assay method techniques having just started in March 2010; several analytical techniques have been under investigation within this program for two to three years or more. This report summarizes work performed over a nine month period from January-September 2011 and is to be considered a follow-on or add-on report to our previous published summary report from December 2010 (INL/EXT-10-20620).

  8. Sedimentary rock porosity studied by electromagnetic techniques: nuclear magnetic resonance and dielectric permittivity

    NASA Astrophysics Data System (ADS)

    Ramia, M. E.; Martín, C. A.

    2015-02-01

    The present work involves a comprehensive experimental study of porosity and pore size distribution of sedimentary rocks, from oil fields formations, by means of two electromagnetic techniques, namely proton (1H) nuclear magnetic resonance (NMR) and dielectric complex constant (DCC) as function of the frequency, both providing complementary results. The NMR yields an accurate determination of the relative pore size distribution and both movable and irreducible fluids. The DCC measurement provides the direct current electrical resistivity of the samples with different degrees of hydration. Thus, combining the results of both techniques allows the determination of the tortuosity index, by means of Archie's relation, and from it the average pore channel length. These measurements are performed on fully hydrated (saturated), centrifuged, dried, and cleaned rocks and also on samples with the irreducible fluids. Finally, the results are complemented with capillary pressure measurements to obtain the total volume associated with the pore channels related to the rock permeability. Additionally, the work presents a particular method to use a network analyzer to measure the DCC.

  9. Study of a defect detection accuracy of a granite nondestructive resonance technique based on a laser interferometer

    NASA Astrophysics Data System (ADS)

    Pod?orny, Tomasz; Budzy?, Grzegorz; Rzepka, Janusz; Tkaczyk, Jakub

    2014-05-01

    A nondestructive testing technique based on a resonance approach and a laser interferometer device is introduced in the presented paper. It utilizes a not synchronized with an acquisition device and low power excitation source. Induced vibrations are acquired using high resolution laser interferometer in a configuration of a vibrometer. As a result, the test equipment is significantly simplified and tailored to the industry requirements. Sample evaluation process is based on a processing that fits lowest order resonance frequencies to p-wave and s-wave frequencies. Obtained velocities are used to fit higher order resonance frequencies present in the response with positions and lengths of resonators formed by cracks or flaws. Presented research focuses on an assessment of accuracy and sensitivity of the introduced method. Performed measurements revealed that it is possible to obtain decent parameters for industry applications.

  10. Electron Spin Resonance Experiments on Donors in Silicon. I. Electronic Structure of Donors by the Electron Nuclear Double Resonance Technique

    Microsoft Academic Search

    G. Feher

    1959-01-01

    The ground-state wave function of the antimony, phosphorus, and arsenic impurities in silicon has been investigated by means of the electron nuclear double resonance (ENDOR) method. By this method the hyperfine interactions of the donor electron with the Si29 nuclei situated at different lattice sites were obtained. The isotropic part of the hyperfine interaction agreed with the theory of Kohn

  11. A study of the nonorthogonal FDTD method versus the conventional FDTD technique for computing resonant frequencies of cylindrical cavities

    Microsoft Academic Search

    Paul H. Harms; Jin-Fa Lee; Raj Mittra

    1992-01-01

    The nonorthogonal finite-difference-time-domain (FDTD) technique is used to compute the resonant frequencies of dielectric-filled cylindrical cavities. Because the method is based on the nonorthogonal coordinate system, it is not restricted to specific geometries, e.g. rectangular or axially symmetric geometries, and is suitable for analyzing cavities of arbitrary shape. The advantages of this technique over the conventional FDTD algorithm with a

  12. NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts

    SciTech Connect

    Not Available

    1991-01-14

    Copper and cobalt are the key elements in syngas conversion catalyst systems used for higher alcohol synthesis. Their proximity and synergy sensitively control the selectivity and efficiency of the process. It is believed that their outer electronic charge distribution which is responsible for their electrical and magnetic properties might be governing their catalytic properties also. To examine the correlation between catalytic and magnetic properties, a series of copper cobalt catalysts (Co/Cu ratio 5:1 to 5:5) with and without a support were prepared. The nuclear quadrupole resonance spectrum of copper and (zero-field) nuclear magnetic resonance spectrum of cobalt and magnetization and hysteresis character of the catalyst were analyzed. Similar to the catalytic results, the magnetic results also were found to be very sensitive to the preparation technique. The results indicate possible electron exchange between copper and cobalt, and cobalt and the support Titania.

  13. The basal permeability to water of human red blood cells evaluated by a nuclear magnetic resonance technique

    Microsoft Academic Search

    Gheorghe Benga; Victor Ioan Pop; Octavian Popescu; Victoria Borza

    1990-01-01

    The characteristics of water diffusional permeability (P) of human red blood cells were studied on isolated erythrocytes by a doping nuclear magnetic resonance technique. In order to estimate the basal permeability the maximal inhibition of water diffusion was induced by exposure of red blood cells to p-chloromercuribenzene sulfonate (PCMBS) under various conditions (concentration, duration, temperature). The lowest values of P

  14. Electrochemical surface plasmon resonance measurement based on gold nanohole array fabricated by nanoimprinting technique.

    PubMed

    Nakamoto, Kohei; Kurita, Ryoji; Niwa, Osamu

    2012-04-01

    In this paper, we describe our development of an electrochemical surface plasmon resonance (EC-SPR) measurement device based on a bottom-filled gold nanohole array. The polymer based gold nanohole array was fabricated with a UV nanoimprint technique and electron beam gold deposition. Direct reflection mode measurement was used to monitor the SPR dip in the reflection spectra. A cyclic voltammogram was also operated by using the standard three electrodes containing working electrode having a gold nanohole array and counter and reference electrodes. The gold nanohole array was modified with an osmium-poly(vinylpyridine)-wired horseradish peroxidase (Os-gel-HRP) film, and its redox state induced by the change in potential was monitored simultaneously. The redox state of the local film was obtained simply by scanning the sample substrate stage. The substrate modified with Os-gel-HRP film was incorporated in a microfluidic chip, and then the hydrogen peroxide was determined in terms of the redox change in the Os complex mediator from the slope of the SPR dip shift. The linear relation of hydrogen peroxide from 10 to 250 ?M was successfully monitored, and a high conversion efficiency was realized. PMID:22283116

  15. Determination of nucleic acids with a near infrared cyanine dye using resonance light scattering technique

    NASA Astrophysics Data System (ADS)

    Fang, Fang; Zheng, Hong; Li, Ling; Wu, Yuqin; Chen, Jinlong; Zhuo, Shujuan; Zhu, Changqing

    2006-06-01

    A new method for the determination of nucleic acids has been developed based on the enhancement effect of resonance light scattering (RLS) with a cationic near infrared (NIR) cyanine dye. Under the optimal conditions, the enhanced RLS intensity at 823 nm is proportional to the concentration of nucleic acids in the range of 0-400 ng mL -1 for both calf thymus DNA (CT DNA) and fish sperm DNA (FS DNA), 0-600 ng mL -1 for snake ovum RNA (SO RNA). The detection limits are 3.5 ng mL -1, 3.4 ng mL -1 and 2.9 ng mL -1 for CT DNA, FS DNA and SO RNA, respectively. Owing to performing in near infrared region, this method not only has high sensitivity endowed by RLS technique but also avoids possible spectral interference from background. It has been applied to the determination of nucleic acids in synthetic and real samples and satisfactory results were obtained.

  16. In vivo biodistribution and biological impact of injected carbon nanotubes using magnetic resonance techniques

    PubMed Central

    Al Faraj, Achraf; Fauvelle, Florence; Luciani, Nathalie; Lacroix, Ghislaine; Levy, Michael; Crémillieux, Yannick; Canet-Soulas, Emmanuelle

    2011-01-01

    Background: Single-walled carbon nanotubes (SWCNT) hold promise for applications as contrast agents and target delivery carriers in the field of nanomedicine. When administered in vivo, their biodistribution and pharmacological profile needs to be fully characterized. The tissue distribution of carbon nanotubes and their potential impact on metabolism depend on their shape, coating, and metallic impurities. Because standard radiolabeled or fluorescently-labeled pharmaceuticals are not well suited for long-term in vivo follow-up of carbon nanotubes, alternative methods are required. Methods: In this study, noninvasive in vivo magnetic resonance imaging (MRI) investigations combined with high-resolution magic angle spinning (HR-MAS), Raman spectroscopy, iron assays, and histological analysis ex vivo were proposed and applied to assess the biodistribution and biological impact of intravenously injected pristine (raw and purified) and functionalized SWCNT in a 2-week longitudinal study. Iron impurities allowed raw detection of SWCNT in vivo by susceptibility-weighted MRI. Results: A transitional accumulation in the spleen and liver was observed by MRI. Raman spectroscopy, iron assays, and histological findings confirmed the MRI readouts. Moreover, no acute toxicological effect on the liver metabolic profile was observed using the HR-MAS technique, as confirmed by quantitative real-time polymerase chain reaction analysis. Conclusion: This study illustrates the potential of noninvasive MRI protocols for longitudinal assessment of the biodistribution of SWCNT with associated intrinsic metal impurities. The same approach can be used for any other magnetically-labeled nanoparticles. PMID:21499425

  17. An adaptive fuzzy-neural-network controller for ultrasonic motor drive using the LLCC resonant technique.

    PubMed

    Lin, F J; Wai, R J; Lin, H H

    1999-01-01

    In this study an adaptive fuzzy-neural-network controller (AFNNC) is proposed to control a rotary traveling wave-type ultrasonic motor (USM) drive system. The USM is derived by a newly designed, high frequency, two-phase voltage source inverter using two inductances and two capacitances (LLCC) resonant technique. Then, because the dynamic characteristics of the USM are complicated and the motor parameters are time varying, an AFNNC is proposed to control the rotor position of the USM. In the proposed controller, the USM drive system is identified by a fuzzy-neural-network identifier (FNNI) to provide the sensitivity information of the drive system to an adaptive controller. The backpropagation algorithm is used to train the FNNI on line. Moreover, to guarantee the convergence of identification and tracking errors, analytical methods based on a discrete-type Lyapunov function are proposed to determine the varied learning rates of the FNNI and the optimal learning rate of the adaptive controller. In addition, the effectiveness of the adaptive fuzzy-neural-network (AFNN) controlled USM drive system is demonstrated by some experimental results. PMID:18238472

  18. Robust control of linear ceramic motor drive with LLCC resonant technique.

    PubMed

    Wai, Rong-Jong

    2003-07-01

    This study presents a robust control system for a linear ceramic motor (LCM) that is driven by a high-frequency voltage source inverter using two-inductance two-capacitance (LLCC) resonant technique. The structure and driving principle of the LCM are introduced. Because the dynamic characteristics and motor parameters of the LCM are nonlinear and time varying, a robust control system is designed based on the hypothetical dynamic model to achieve high-precision position control. The presentation of robust control for the LCM drive system is divided into three parts, which comprise state feedback controller, feed-forward controller, and uncertainty controller. The adaptation laws of control gains in the robust control system are derived in the sense of Lyapunov stability theorem such that the stability of the control system can be guaranteed. It not only has the learning ability similar to intelligent control, but also its control framework is more simple than intelligent control. With the proposed robust control system, the controlled LCM drive possesses the advantages of good tracking control performance and robustness to uncertainties. The effectiveness of the proposed robust control system is verified by experimental results in the presence of uncertainties. In addition, the advantages of the proposed control system are indicated in comparison with the traditional integral-proportional (IP) position control system. PMID:12894924

  19. Cardiovascular function and flow by 4-dimensional magnetic resonance imaging techniques: new applications.

    PubMed

    Calkoen, Emmeline E; Roest, Arno A W; van der Geest, Rob J; de Roos, Albert; Westenberg, Jos J M

    2014-05-01

    Acquisition techniques related to 4-dimensional (4D) flow magnetic resonance imaging (MRI) improved rapidly over the last 3 decades. Most importantly, a major improvement was the acceleration of the acquisition, which resulted in a clinically feasible scan duration and led to more comprehensive use of 4D flow MRI in clinical research. This resulted in several new applications of 4D flow MRI for the evaluation of various physiological and pathologic cardiovascular flow patterns. Visualization tools aim at displaying the direction and magnitude of blood flow velocity from 4D flow data, by using for instance a vector glyph or streamline representation or by constructing pathlines from particle tracing. Such tools are applied to provide insight in the temporal distribution of the 3D flow velocity and enable the quantification of hemodynamic markers. These hemodynamic markers play an important role in the quantitation of abnormalities in cardiovascular blood flow patterns and the characterization of vascular and myocardial remodelling, which can possibly be used to predict pathology such as heart failure, aortic dissection, or aneurysm or thrombus formation. This review focuses on the clinical use of 4D flow MRI and presents an overview of new applications of visualization and quantification tools to describe physiological and pathologic cardiovascular blood flow. PMID:24576838

  20. Influence of resonant Raman scattering in the elemental analysis using X-ray emission based techniques

    NASA Astrophysics Data System (ADS)

    Kumar, Sunil; Singh, Gurjeet; Kumar, Sanjeev; Mehta, D.; Singh, Nirmal

    2010-08-01

    A tabulation of characteristic X-ray energies across the periodic table are provided where those X-rays are expected to result in a significant fractional resonant Raman scattering (RRS) contribution to the X-ray attenuation from a particular shell/subshell of the same or another element. The tabulations can be considered as guideline so as to know what can be expected due to RRS in typical photon- and particle-induced X-ray emission spectrometry. The RRS contribution is not included in the available theoretical attenuation coefficients, which are generally used in estimation of the matrix corrections in routine quantitative elemental analysis based on various X-ray emission techniques. The radiative RRS peaks can also interfere with normal X-ray spectrum and influence the elemental analysis. The RRS cross-section depends upon the energy difference of the X-ray energy and the shell/subshell ionization threshold taken in the units of the shell/subshell energy width, density of available states near the Fermi level, and the band structure in case the element is in the solid form. Some aspects of the dependence of the RRS contribution on the chemical forms of the elements are also discussed.

  1. Application of Resonant Frequency Eddy Current Technique on a Shot-Peened Nickel-Based Engine-Grade Material

    SciTech Connect

    Ko, Ray T.; Sathish, Shamachary; Boehnlein, Thomas R. [Structural Integrity Division, University of Dayton Research Institute, 300 College Park Drive, Dayton, Ohio 45469-0120 (United States); Blodgett, Mark P. [Metals, Ceramics, and NDE Division, Air Force Research Laboratory, Wright-Patterson Air Force Base, Dayton, Ohio 45433 (United States)

    2007-03-21

    The shot peening conditions of a nickel-based engine-grade material were evaluated using a novel eddy current measurement technique. With this technique, the shift of a resonant frequency was found to be dependent on variables which also affect conventional eddy current testing. The cable effect is another important variable, which is often neglected in a routine eddy current testing, is also discussed. Experimental results showed that at high frequencies, the shot peening conditions were easily distinguishable using this frequency shift technique.

  2. Techniques and processes for the measurement of the resonances of small single crystals

    SciTech Connect

    Migliori, A.; Stekel, A.; Sarrao, J.L.; Visscher, W.M.; Bell, T.; Lei, M.

    1991-01-01

    The mechanical resonances of small oriented single crystals of materials of interest to basic science and engineering can be used to determine all the elastic moduli and the ultrasonic attenuation of these materials. To measure the resonances of the samples without introducing the resonances of the measuring system requires that the transducers be non-resonant at the frequencies of interest, and that they be well isolated from their mounts. However, for samples near 1 mm in the largest dimension, the transducer design problem becomes sever, and the signals become weak. In addition, no resonances can be missed, and, often, the symmetry class of the resonances must be known. We outline here appropriate transducer, electronics, and system designs to circumvent these problems. 10 refs., 4 figs.

  3. Cu nuclear magnetic resonance of aligned single crystals of YBaâCuâOâ. sqrt. \\/sub delta

    Microsoft Academic Search

    C. H. Pennington; D. J. Durand; D. B. Zax; C. P. Slichter; J. P. Rice; D. M. Ginsberg

    1988-01-01

    There are two types of Cu sites in YBaâCuâOâ..sqrt..\\/sub delta\\/, plane and chain. One gives a nuclear quadrupole resonance (NQR) at 22.0 MHz, the other at 31.5 MHz. Measurements of nuclear spin-lattice relaxation time in the superconducting state show that the 31.5-MHz site has a much larger energy gap (as though its T\\/sub c\\/ were 200 K), but different experimental

  4. Cu nuclear magnetic resonance of aligned single crystals of YBa2Cu3O7-delta

    Microsoft Academic Search

    C. H. Pennington; D. J. Durand; D. B. Zax; C. P. Slichter; J. P. Rice; D. M. Ginsberg

    1988-01-01

    There are two types of Cu sites in YBa2Cu3O7-delta, plane and chain. One gives a nuclear quadrupole resonance (NQR) at 22.0 MHz, the other at 31.5 MHz. Measurements of nuclear spin-lattice relaxation time in the superconducting state show that the 31.5-MHz site has a much larger energy gap (as though its Tc were 200 K), but different experimental workers have

  5. Determination of Soil Hydraulic Properties Using Magnetic Resonance Techniques and Classical Soil Physics Measurements

    NASA Astrophysics Data System (ADS)

    Stingaciu, Laura R.; Weihermüller, Lutz; Pohlmeier, Andreas; Stapf, Siegfried; Vereecken, Harry

    2011-03-01

    Water and solute movement as any other transport processes through soil are influenced by the hydraulic properties of the soils. The heterogeneities of the soils imply heterogeneous spatial distribution of the hydraulic properties leading to heterogeneous distribution of soil water content. This may affects the water availability for plant growth, the groundwater contamination and nutrients losses within the root zone. The measurement techniques available today for the estimation of soil hydraulic parameters do not account for the heterogeneity of the sample and treat each measurement sample as a homogeneous representative volume. On the other side natural soils contain large heterogeneities mostly in terms of inclusions of different materials. Therefore the purpose of this study is to estimate soil hydraulic properties of a heterogeneous sample by combining classical multi-step-outflow (MSO) with magnetic resonance imaging (MRI) experiments. MSO experiments were performed on a sample filled with sand and sand-clay mixture in a coaxial structure. During each pressure application MRI images at 4.7 T (200 MHz) were recorded using a pure phase-encoding MRI sequence in order to provide information about the soil water content at specific locations within the coaxial sample. The recorded cumulative outflow and water content data were used as input data in the inversion of the MSO experiment. For the simulation and inversion of the MSO experiment we used the hydrological model HYDRUS-2D3D in which the initial hydraulic parameters of the two materials were estimated based on CPMG-T2 relaxation measurements on homogeneous sub-samples. The results show conclusively that the combination of the two MRI and MSO methods leads to a unique estimation of the hydraulic properties of two materials simultaneously.

  6. A comparison of different pulse sequences in the nondestructive estimation of seed oil by pulsed nuclear magnetic resonance technique

    Microsoft Academic Search

    V. T. Srinivasan

    1979-01-01

    Three basic pulse sequences,viz., Free Induction Decay (FID), Spin Echo (SE) and Carr-Purcell-Meiboom-Gill (CPMG), available in the pulsed nuclear magnetic\\u000a resonance technique have been used to estimate the relative oil content in single as well as bulk samples of oil-bearing seeds.\\u000a Conclusive evidence has been presented to show that the CPMG sequence is vastly superior to the other two as

  7. Mie resonance-mediated antireflection effects of Si nanocone arrays fabricated on 8-in. wafers using a nanoimprint technique

    NASA Astrophysics Data System (ADS)

    Kim, Eunah; Cho, Yunae; Park, Kwang-Tae; Choi, Jun-Hyuk; Lim, Seung-Hyuk; Cho, Yong-Hoon; Nam, Yoon-Ho; Lee, Jung-Ho; Kim, Dong-Wook

    2015-04-01

    We fabricated 8-in. Si nanocone (NC) arrays using a nanoimprint technique and investigated their optical characteristics. The NC arrays exhibited remarkable antireflection effects; the optical reflectance was less than 10% in the visible wavelength range. The photoluminescence intensity of the NC arrays was an order of magnitude larger than that of a planar wafer. Optical simulations and analyses suggested that the Mie resonance reduced effective refractive index, and multiple scattering in the NCs enabled the drastic decrease in reflection.

  8. Dataset of Magnetic Resonance Images of Nonepileptic Subjects and Temporal Lobe Epilepsy Patients for Validation of Hippocampal Segmentation Techniques

    Microsoft Academic Search

    Kourosh Jafari-Khouzani; Kost V. Elisevich; Suresh Patel; Hamid Soltanian-Zadeh

    The hippocampus has become the focus of research in several neurodegenerative disorders. Automatic segmentation of this structure\\u000a from magnetic resonance (MR) imaging scans of the brain facilitates this work. Segmentation techniques must be evaluated using\\u000a a dataset of MR images with accurate hippocampal outlines generated manually. Manual segmentation is not a trivial task. Lack\\u000a of a unique segmentation protocol and

  9. Operation Dominic, Fish Bowl Series. Project Officer's report. Project 6. 6. Long-term observations by resonance-scattering techniques

    Microsoft Academic Search

    Manring

    1985-01-01

    Some of the apparent conclusions of this project are (1) low-yield, low-altitude devices do not lend themselves to a study by resonance-scatter techniques; (2) devices such as King Fish, Star Fish, very-high-yield weapons at 50 km or higher, and low-yield weapons salted with an appropriate material, give debris concentrations that can be followed for many days and over wide geographical

  10. 8128 J.Am. Chem. SOC.1993,115, 8128-8741 A Nuclear Magnetic Resonance Spectroscopic Technique for

    E-print Network

    Reich, Hans J.

    8128 J.Am. Chem. SOC.1993,115, 8128-8741 A Nuclear Magnetic Resonance Spectroscopic Technique) Reich, H. J.; Green,D. P.; Phillips, N. H.J.Am. Chem.Soc. 1989, 111.3444. (b)Reich, H.J.;Green, D. P.J.Am.Chem.Soc. 1989,111,8729. (c) Reich, H.J.; Green, D. P.; Phillips, N. H. J.Am. Chem.SOC.1991, 113, 1414. (d

  11. An iterative technique for refinement of selective excitations for magnetic resonance imaging

    E-print Network

    Lebsack, Eliot Todd

    1999-01-01

    Selective RF pulses are needed or many application in magnetic resonance imaging (MRI). The desired excitation profile is omen used as the spectrum of the applied RF pulse; the modulation waveform of the RF pulse which approximately excites...

  12. Local molecular spectroscopy using the evanescent microwave probe technique: electron spin resonance

    Microsoft Academic Search

    Massood Tabib-Azar; Xiying Li; J. Adin Mann

    2005-01-01

    A method based on evanescent microwave microscopy (EMM) was developed to spatially resolve small number of electron spin resonant (ESR) transitions in single crystal ruby (Cr3+). The EMM probe operates at a resonance frequency of 3.77 GHz (S-band ESR) in a modulated electromagnetic field in the range of 0.02 to 0.6 Tesla. The current EMM probe with a magnetic dipole

  13. A two-frequency acoustic technique for bubble resonant oscillation studies

    PubMed

    Ohsaka; Trinh

    2000-03-01

    A two-frequency acoustic apparatus has been developed to study the dynamics of a single gas or vapor bubble in water. An advantage of the apparatus is its capability of trapping a bubble by an ultrasonic standing wave while independently driving it into oscillations by a second lower frequency acoustic wave. For a preliminary application, the apparatus is used to study resonant oscillations. First, near-resonant coupling between the volume and the n = 3 shape oscillation modes of air bubbles at room temperature is studied, where n is the mode number. The stability boundary, amplitude versus frequency, of the volume oscillation forms a wedge centered at the resonant frequency, which qualitatively agrees with a theoretical prediction based on a phase-space analysis. Next, the resonant volume oscillations of vapor bubbles are studied. The resonant radius of vapor bubbles at 80 degrees C driven at 1682 Hz is determined to be 0.7 mm, in agreement with a prediction obtained by numerical simulation. PMID:10738788

  14. A study of the semiconductor compound ?uAlO2 by the method of nuclear quadrupole resonance of Cu

    NASA Astrophysics Data System (ADS)

    Matukhin, V. L.; Khabibulin, I. Kh.; Shul'gin, D. A.; Smidt, S. V.

    2012-07-01

    The method of nuclear quadrupole resonance of Cu (NQR Cu) is used to study the samples of a semiconductor compound CuAlO2. The crystal structure of CuAlO2 belongs to the family of delafossite - the mineral of a basic CuFeO2 structure. Transparent semiconductor oxides, such as CuAlO2, have attracted recent attention as promising thermoelectric materials.

  15. Integrated system for production of neutronics and photonics calculational constants. Volume 11. Experimental data, indexes, and techniques of obtaining a selected set of neutron resonance parameters

    SciTech Connect

    Gyulassy, M.; Howerton, R.J.; Perkins, S.T.

    1972-05-01

    A tabulation is presented of 52,000 experimental resonance parameters, together with appropriate indexes and bibliographic citations. These materials were contained in the LLL Experimental Neutron Cross Section Library as of May 1, 1972. Techniques used to obtain a selected set of resolved and unresolved resonance parameters from the compilation are described. (auth)

  16. The influence of the analysis technique on estimating liver iron overload using magnetic resonance imaging T2* quantification.

    PubMed

    Ibrahim, El-Sayed H; Khalifa, Ayman M; Eldaly, Ahmed K

    2014-01-01

    Iron toxicity is the major cause of tissue damage in patients with iron overload. Iron deposits mainly in the liver, where its concentration closely correlates with whole body iron overload. Different techniques have been proposed for estimating iron content, with liver biopsy being the gold standard despite its invasiveness and influence by sampling error. Recently, magnetic resonance imaging (MRI) has been established as an effective technique for evaluating iron overload by measuring T2(*) in the liver. However, various factors associated with the adopted analysis technique, mainly the exponential fitting model and signal averaging method, affect the resulting measurements. In this study, we evaluate the influences of these factors on T2(*) measurement in numerical phantom, calibrated phantoms, and nine patients with different degrees of iron overload. The results show different performances among the fitting models and signal averaging methods, which are affected by SNR, image quality and signal homogeneity inside the selected ROI for analysis. PMID:25571026

  17. Magnetic resonance imaging and cerebral volumic evaluation: comparison of four post-processing techniques.

    PubMed

    Dorion, A A; Salomon, O; Zanca, M; Duyme, M; Capron, C

    2001-07-01

    Four different MRI techniques of volumetric evaluation were applied in 10 healthy females and compared. The results have shown that not all techniques were interchangeable, but that the results of two groups of methods are not statistically different. PMID:11334632

  18. Inverse scattering technique for resonator alignment - Dependence of the accuracy on the finesse and mirror alignment

    Microsoft Academic Search

    S. Solimeno; Fabrizio Barone; Luciano di Fiore; Leopoldo Milano; Innocenzo M. Pinto

    1989-01-01

    The sensitivity of a GW interferometric antenna depends critically on the alignment of the Fabry-Perot (F-P) resonators placed in the two atms of a Michelson interferometer. To this end a servo system can be used for controlling the position and the orientation of the end mirrors by using error signals obtained by analyzing the transverse distribution of the beams reflected

  19. Techniques and mechanisms applied in electron cyclotron resonance sources for highly charged ions

    Microsoft Academic Search

    A. G. Drentje

    2003-01-01

    Electron cyclotron resonance ion sources are delivering beams of highly charged ions for a wide range of applications in many laboratories. For more than two decades, the development of these ion sources has been to a large extent an intuitive and experimental enterprise. Much effort has been spent in theoretical work, but a consistent description still is not available. From

  20. Measurement of lateral stress in argon implanted thin gold lms using quartz resonator techniques

    E-print Network

    Webb, Roger P.

    energy implantation of large molecules to achieve ultra-shallow modi®ed layers (see Ref. [1] for ex the results of a three- quartz-crystal-resonator experiment designed to accurately measure lateral stress backscattering (RBS) and then using this information to Nuclear Instruments and Methods in Physics Research B 148

  1. Magnetic penetration depth measurements of superconducting thin films by a microstrip resonator technique

    E-print Network

    Anlage, Steven

    Magnetic penetration depth measurements of superconducting thin films by a microstrip resonator dependence of the magnetic penetration depth, n(T), in superconducting thin films. Because the method relies-lying pair breaking excitations of the superconductor. Absolute penetration depth values can also be obtained

  2. Optimal control technique for magnet design in inside-out nuclear magnetic resonance

    Microsoft Academic Search

    Bruno Luong; Jaideva C. Goswami; Apo Sezginer; Dylan Davies

    2001-01-01

    The magnets used in a family of inside-out nuclear magnetic resonance (NMR) well-logging tools usually consist of several segments of magnet materials, with each segment magnetized differently. In a tool, the magnet is surrounded with a nonlinear magnetic material, such as ferrite or steel, that is primarily used in the RF coil or in shielding the electronic components from strong

  3. Determination of rock acoustic properties at low frequency: A differential acoustical resonance spectroscopy device and its estimation technique

    NASA Astrophysics Data System (ADS)

    Zhao, Jianguo; Tang, Genyang; Deng, Jixin; Tong, Xiaolong; Wang, Shangxu

    2013-06-01

    A laboratory device, Differential Acoustic Resonance Spectroscopy (DARS), has been developed to investigate the acoustic properties of rock materials below 1 KHz. The device is based on analyzing shifts of resonance frequency of a cavity perturbed by the presence of a small sample. Numerical and experimental studies have previously shown that this technique can be used to estimate the compressibility of samples. In this study, we adopt a nonlinear least-squares whole-curve-fitting inversion approach, which for the first time allows estimation of both the compressibility and density of rock samples. In comparison to previous estimation techniques, this inversion method provides more reliable estimation of rock acoustic properties. This research proves that the DARS laboratory device, in conjunction with the calibration technique proposed herein, is a useful tool to estimate the properties of small rock samples. In addition, the simultaneous estimation of compressibility and density can potentially provide information on porosity and, by extension, a link between porosity and acoustic modulus at low frequency.

  4. CVD graphene growth and transfer techniques for the fabrication of micromechanical resonators

    NASA Astrophysics Data System (ADS)

    Losowyj, Daniel; Storch, Isaac; McCune, Thomas; McEuen, Paul

    2013-03-01

    Graphene's superlative mechanical strength, electrical mobility, low mass, and large surface area make it a prime candidate for use in micromechanical resonators, which have potential applications in mass and force sensing, radio frequency signal processing, and optomechanics. Our resonators use graphene grown by chemical vapor deposition (CVD) and have excellent mechanical performance, but their electrical performance is comparatively worse than that of exfoliated graphene devices. We attribute these limitations to contamination from copper oxidation during the growth and solvents used in the transfer process. To remedy this, we have performed CVD growths on copper foils with long anneal times, confirming with Raman spectroscopy and SEM that the graphene is single layer and high quality. We have also found that graphene suspended on a substrate can survive high temperature air annealing, provided that the temperature ramp is gradual. Improving the electrical performance of these novel devices will facilitate their use in a variety of new experiments and applications.

  5. Method for high resolution magnetic resonance analysis using magic angle technique

    DOEpatents

    Wind, Robert A.; Hu, Jian Zhi

    2003-12-30

    A method of performing a magnetic resonance analysis of a biological object that includes placing the object in a main magnetic field (that has a static field direction) and in a radio frequency field; rotating the object at a frequency of less than about 100 Hz around an axis positioned at an angle of about 54.degree.44' relative to the main magnetic static field direction; pulsing the radio frequency to provide a sequence that includes a phase-corrected magic angle turning pulse segment; and collecting data generated by the pulsed radio frequency. The object may be reoriented about the magic angle axis between three predetermined positions that are related to each other by 120.degree.. The main magnetic field may be rotated mechanically or electronically. Methods for magnetic resonance imaging of the object are also described.

  6. Method for high resolution magnetic resonance analysis using magic angle technique

    DOEpatents

    Wind, Robert A.; Hu, Jian Zhi

    2004-12-28

    A method of performing a magnetic resonance analysis of a biological object that includes placing the object in a main magnetic field (that has a static field direction) and in a radio frequency field; rotating the object at a frequency of less than about 100 Hz around an axis positioned at an angle of about 54.degree.44' relative to the main magnetic static field direction; pulsing the radio frequency to provide a sequence that includes a phase-corrected magic angle turning pulse segment; and collecting data generated by the pulsed radio frequency. The object may be reoriented about the magic angle axis between three predetermined positions that are related to each other by 120.degree.. The main magnetic field may be rotated mechanically or electronically. Methods for magnetic resonance imaging of the object are also described.

  7. Magnetic Resonance Spectrum Technique in the Follow-up of an Ulnar Nerve Injured Patient

    PubMed Central

    Wu, Yihui; Yang, Bo; Bao, Qiyuan; Ye, Chuntao; Wang, Tao; Xie, Yaling; Jia, Jianchang; Xue, Aimin; Ji, Ming

    2015-01-01

    Summary: A 49-year-old Chinese man sustained laceration of the right forearm by a dagger, with his right ulnar nerve completely transected. Four months postinjury, he underwent surgery to repair the nerve. He was examined by electromyogram, nerve conduction velocity, magnetic resonance imaging, and proton magnetic resonance spectroscopy (1H-MRS) 6, 12, 18, and 24 months after the injury. Before surgery, intramyocellular lipid (IMCL)/creatine (Cr) and extramyocellular lipid (EMCL)/Cr were observed to be higher than those of the uninjured side. During the recovery, IMCL/Cr and EMCL/Cr became lower and closer to the uninjured side. This case demonstrates that the change of IMCL/Cr and EMCL/Cr may be related to the recovery of peripheral nerve. PMID:26090293

  8. Determination of nucleic acids with a near infrared cyanine dye using resonance light scattering technique

    Microsoft Academic Search

    Fang Fang; Hong Zheng; Ling Li; Yuqin Wu; Jinlong Chen; Shujuan Zhuo; Changqing Zhu

    2006-01-01

    A new method for the determination of nucleic acids has been developed based on the enhancement effect of resonance light scattering (RLS) with a cationic near infrared (NIR) cyanine dye. Under the optimal conditions, the enhanced RLS intensity at 823nm is proportional to the concentration of nucleic acids in the range of 0–400ngmL?1 for both calf thymus DNA (CT DNA)

  9. Determination of nucleic acids at nanogram level using resonance light scattering technique with Congo Red

    Microsoft Academic Search

    Xia Wu; Yuebo Wang; Minqin Wang; Shuna Sun; Jinghe Yang; Yuxia Luan

    2005-01-01

    Based on the enhancement of the resonance light scattering (RLS) of Congo Red (CR) by nucleic acid, a new quantitative method for nucleic acid is developed. In the Tris–HCl buffer (pH 10.5), the weak light scattering of CR is greatly enhanced by addition of nucleic acid and CTMAB, the maximum peak is at 560nm and the enhanced intensity of RLS

  10. beta-decay studies of 135-137Sn using selective resonance laser ionization techniques

    Microsoft Academic Search

    J. Shergur; B. A. Brown; V. Fedoseyev; U. Köster; K.-L. Kratz; D. Seweryniak; W. B. Walters; A. Wöhr; D. Fedorov; M. Hannawald; M. Hjorth-Jensen; V. Mishin; B. Pfeiffer; J. J. Ressler; H. O. Fynbo; P. Hoff; H. Mach; T. Nilsson; K. Wilhelmsen-Rolander; H. Simon; A. Bickley

    2002-01-01

    The decays of the very neutron rich Sn isotopes 135-137Sn were studied at CERN\\/ISOLDE using isotopic and isobaric selectivity achieved by the use of a resonance ionization laser ion source and mass spectroscopy, respectively. Neutron decay rates, gamma-ray singles, and gamma-gamma coincidence data were collected as a function of time. The half-life (T1\\/2) and delayed neutron emission probability (Pn) values

  11. Determination of antibacterial quaternary ammonium compound in lozenges and human serum by resonance light scattering technique

    Microsoft Academic Search

    Zhanguang Chen; Yurui Peng; Junhui Chen; Li Zhu

    2008-01-01

    A method for the specific determination of an antibacterial quaternary ammonium compound Dequalinium chloride (DQC) was described in this paper. At pH 0.5, the resonance light scattering (RLS) intensity of sodium dodecyl benzene sulfonate (SDBS) remarkably was enhanced by adding DQC. A RLS peak at 392.0nm was found, and the enhanced intensity of RLS at this wavelength was proportional to

  12. Stable absolute calibration standards for hydrogen profile analysis using nuclear resonance techniques

    Microsoft Academic Search

    L. Westerberg; L. E. Svensson; E. Karlsson; M. W. Richardson; K. Lundström

    1985-01-01

    Samples of pyrolytic carbon, CHx (x ~ 0.03) from pyrolysis of methane, and amorphous silicon, SiHx (x ~ 0.2) from plasma deposition of silane, are shown to be stable during ion bombardment and vacuum storage. They are therefore well suited as calibration standards for hydrogen profile analysis using nuclear resonance reactions such as 1H(15N, alphagamma)12C. Due to its high hydrogen

  13. Predicting caking behaviors in powdered foods using a low-field nuclear magnetic resonance (NMR) technique

    Microsoft Academic Search

    Myong-Soo Chung; Roger Ruan; Paul Chen; Jin-Ho Kim; Tae-Hoi Ahn; Chang-Kyu Baik

    2003-01-01

    This study is concerned with caking of powder mixes. Our previous study tied the caking process to the nuclear magnetic resonance (NMR) spin–spin (T2) relaxation characteristics exhibited by powder ingredients subjected to temperature scan from –20°C to 110°C (Journal of Food Science 65 (1) (2000) 134). Four temperature–T2 curve patterns were identified, each of which represents a group of powder

  14. Resonator micro optic gyro with double phase modulation technique using an FPGA-based digital processor

    NASA Astrophysics Data System (ADS)

    Jin, Zhonghe; Zhang, Guhong; Mao, Hui; Ma, Huilian

    2012-03-01

    Experiments on resonator micro-optic gyro (RMOG) with a digital proportional integral (PI) feedback scheme are performed. In this experimental setup, the key rotation sensing element is a polarization maintaining silica waveguide ring resonator (WRR) with a ring length of 7.9 cm and a diameter of 2.5 cm. A good linearity of 0.0015% over a wide range of ± 2 × 10 4 °/s can be achieved for the RMOG theoretically. The optimal digital PI feedback scheme is adopted in the frequency servo loop to reduce the reciprocal frequency fluctuations due to the WRR resonance frequency and laser frequency drifts. Residual equivalent input fluctuation can be reduced as low as 0.03 °/s/?Hz based on the optimal digital PI feedback scheme, which is close to the shot noise limited spectral density 0.02 °/s/?Hz of the RMOG with the input optical power of 0.2 mW. Relationship between RMOG output signal and angular rate is obtained from ± 0.1 °/s to ± 5 °/s. The standard deviation of the residuals between RMOG output results and linear fit curve is 0.066 °/s. For an integration of the processing circuit, all the processing circuit is implemented by a field programmable gate array (FPGA) instead of instruments. The output of this digitalized RMOG is obtained over a range of ± 550 °/s. The linearity of this digitalized RMOG is 0.0169%.

  15. High resolution image acquisition from magnetic resonance and computed tomography scans using the curvelet fusion algorithm with inverse interpolation techniques.

    PubMed

    Ali, Fatma E; El-Dokany, Ibrahim M; Saad, Abdelfattah A; Al-Nuaimy, Waleed; Abd El-Samie, Fathi E

    2010-01-01

    We present a new approach, based on the curvelet transform, for the fusion of magnetic resonance and computed tomography images. The objective of this fusion process is to obtain images, with as much detail as possible, for medical diagnosis. This approach is based on the application of the additive wavelet transform on both images and the segmentation of their detail planes into small overlapping tiles. The ridgelet transform is then applied on each of these tiles, and the fusion process is performed on the ridgelet transforms of the tiles. To maximize the benefit of the fused images, inverse interpolation techniques are used to obtain high resolution images from the low resolution fused images. Three inverse interpolation techniques are presented and compared. Simulation results show the superiority of the proposed curvelet fusion approach to the traditional discrete wavelet transform fusion technique. Results also reveal that inverse interpolation techniques have succeeded in obtaining high resolution images from the fused images with better quality than that of the traditional cubic spline interpolation technique. PMID:20062497

  16. Neutron Resonance Transmission Analysis (NRTA): A Nondestructive Assay Technique for the Next Generation Safeguards Initiative’s Plutonium Assay Challenge

    SciTech Connect

    J. W. Sterbentz; D. L. Chichester

    2010-12-01

    This is an end-of-year report for a project funded by the National Nuclear Security Administration's Office of Nuclear Safeguards (NA-241). The goal of this project is to investigate the feasibility of using Neutron Resonance Transmission Analysis (NRTA) to assay plutonium in commercial light-water-reactor spent fuel. This project is part of a larger research effort within the Next-Generation Safeguards Initiative (NGSI) to evaluate methods for assaying plutonium in spent fuel, the Plutonium Assay Challenge. The first-year goals for this project were modest and included: 1) developing a zero-order MCNP model for the NRTA technique, simulating data results presented in the literature, 2) completing a preliminary set of studies investigating important design and performance characteristics for the NRTA measurement technique, and 3) documentation of this work in an end of the year report (this report). Research teams at Los Alamos National Laboratory (LANL), Lawrence Berkeley National Laboratory (LBNL), Pacific Northwest National Laboratory (PNNL), and at several universities are also working to investigate plutonium assay methods for spent-fuel safeguards. While the NRTA technique is well proven in the scientific literature for assaying individual spent fuel pins, it is a newcomer to the current NGSI efforts studying Pu assay method techniques having just started in March 2010; several analytical techniques have been under investigation within this program for two to three years or more. This report summarizes a nine month period of work.

  17. Successive magnetic transition in non-centrosymmetric CeCoGe3 probed by Co-NQR

    NASA Astrophysics Data System (ADS)

    Matsumura, M.; Sato, Y.; Mizoo, M.; Kawamura, Y.; Kato, H.; Nishioka, T.

    2011-01-01

    Co-NQR measurements for non-centrosymmetric superconductor CeCoGe3 have been performed in ambient and under pressure up to 1.5 GPa to investigate the magnetic structures for the successive magnetic transition at TN1=21 K, TN2=12 K and TN3=8 K. In ambient pressure, the crystallographically equivalent one Co site becomes three sites at TN1 > T > TN2, and further becomes four sites at TN2 > T. Applying pressure at 4.2 K, the four Co sites becomes two sites above 0.3 Gpa. These Co sites acquire slightly different internal field parallel to the c-axis, consistent with the anisotropic magnetization with easy c-axis. The T-dependences of the internal fields and the spectral weights for respective sites are estimated. The magnetic structure in each phase is discussed referring to the recent results of neutron scattering.

  18. Cu nuclear magnetic resonance of aligned single crystals of YBa/sub 2/Cu/sub 3/O/sub 7/. sqrt. /sub delta/

    SciTech Connect

    Pennington, C.H.; Durand, D.J.; Zax, D.B.; Slichter, C.P.; Rice, J.P.; Ginsberg, D.M.

    1988-05-01

    There are two types of Cu sites in YBa/sub 2/Cu/sub 3/O/sub 7/..sqrt../sub delta/, plane and chain. One gives a nuclear quadrupole resonance (NQR) at 22.0 MHz, the other at 31.5 MHz. Measurements of nuclear spin-lattice relaxation time in the superconducting state show that the 31.5-MHz site has a much larger energy gap (as though its T/sub c/ were 200 K), but different experimental workers have differed as to whether this is the chain or plane site. We report nuclear magnetic resonance (NMR) studies at 81.1 kG and 100 K on oriented single crystals, and conclude from symmetry arguments that the 31.5-MHz NQR arises from the plane site.

  19. Feasibility Study of Velocity and Temperature Measurements of an Arcjet Flow using Laser Resonance Doppler Velocimetric (LRDV) Technique

    NASA Technical Reports Server (NTRS)

    Rob, Mohammad A.

    1996-01-01

    Thermal Protection System (TPS) materials are used in space vehicles to shield from high heating environment encountered during their atmospheric reentry. Arcjet wind tunnels are used to simulate the flowfield encountered by the spacecrafts, and are used for testing TPS materials. How well these tests simulate the actual heating environment encountered by space vehicles depends on the characteristics of the simulated flow. The flow characterization requires the determination of temperature, concentration, and velocity of the various atomic and molecular species present in the flow. However, determining these parameters requires a complex set of both analytical and experimental procedures. The ability to properly simulate the flight environment is directly related to the accuracy with which these techniques can be used to define the arcjet Laser Resonance Doppler Velocimetric (LRDV) technique can be used to accurately determine the velocity and temperature of a gaseous species. In this technique, the medium is probed with a laser beam that is in resonance with an absorbing transition of the species. The absorption lineshape is Doppler-shifted due to the flow velocity of the species, and the frequency shift is detected as the variation in intensity of the fluorescence emitted by the species. Thus a measurement of the Doppler shift and the width of a spectral line can give both the temperature and the velocity of the flowfield. This summer, our project was to make a feasibility study to set up an experimental arrangement for the laser resonance Doppler velocimetric technique using a ring dye laser. Experiments required troubleshooting, cleaning, testing, and alignment of two lasers and several diagnostics instruments. All instruments and lasers necessary for the project worked well, but the output power of the broadband fundamental dye laser was limited to about 20 mW. This was quite low as compared to that necessary to obtain second harmonic oscillation at 327.49 nm for the LRDV studies. Further optimization of the dye laser optical elements is necessary before it can be used for the experiment, which requires narrowband (about 20 Mhz) laser operation.

  20. H/D isotope effect of 1H MAS NMR spectra and 79Br NQR frequencies of piperidinium p-bromobenzoate and pyrrolidinium p-bromobenzoate

    NASA Astrophysics Data System (ADS)

    Honda, Hisashi; Kyo, Shinshin; Akaho, Yousuke; Takamizawa, Satoshi; Terao, Hiromitsu

    2010-04-01

    H/D isotope effects onto 79Br NQR frequencies of piperidinium p-bromobenzoate were studied by deuterium substitution of hydrogen atoms which form two kinds of N-H?O type hydrogen bonds, and the isotope shift of ca. 100 kHz were detected for a whole observed temperature range. In addition, 1H MAS NMR spectra measurements of piperidinium and pyrrolidinium p-bromobenzoate were carried out and little isotope changes of NMR line shape were detected. In order to reveal effects of molecular arrangements into the obtained isotope shift of NQR frequencies, single-crystal X-ray measurement of piperidinium p-bromobenzoate- d2 and density-functional-theory calculation were carried out. Our estimation showed the dihedral-angle change between piperidine and benzene ring contributes to isotope shift rather than those of N-H lengths by deuterium substitution.

  1. NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts

    SciTech Connect

    Not Available

    1991-12-17

    The primary objective of the project is to examine the relations between the catalytic and magnetic properties of the copper-cobalt higher alcohol synthesis catalysts. We have undertaken to investigate the magnetic character by studying the Nuclear Quadrupole resonance of copper and (Zerofield) Nuclear Magnetic Resonance of cobalt in copper cobalt catalysts.

  2. NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts

    SciTech Connect

    Not Available

    1991-07-15

    The primary objective of the project is to examine the relations between the catalytic and magnetic properties of the copper-cobalt higher alcohol synthesis catalysts. We have undertaken to investigate the magnetic character by studying the Nuclear Quadrupole resonance of copper and (Zerofield) Nuclear Magnetic Resonance of cobalt in copper cobalt catalysts.

  3. Resonance light scattering technique for the determination of protein with rutin and cetylpyridine bromide system

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Yang, Jinghe; Liu, Shufang; Wu, Xia; Su, Benyu; Wu, Tao

    2005-02-01

    A new resonance light scattering (RLS) assay of protein is presented. In Tris-NaOH (pH = 10.93) buffer, the RLS of rutin-cetylpyridine bromide (CPB) system can be greatly enhanced by protein, including bovine serum albumin (BSA) and human serum albumin (HSA). The enhanced RLS intensities are in proportion to the concentration of proteins in the range of 5 × 10 -9 to 2.5 × 10 -6 g ml -1 for BSA and 2.5 × 10 -8 to 3.5 × 10 -6 g ml -1 for HSA. The detection limits (S/N = 3) are 3.0 ng ml -1 for BSA and 10.0 ng ml -1 for HSA. Samples are determined satisfactorily.

  4. Oxygen Content Dependence of 63Cu(1) NQR and Proton NMR in Hydrogen-Doped Antiferromagnetic YBa2Cu3O6+xHy

    NASA Astrophysics Data System (ADS)

    Niki, Haruo; Kano, Kikuhiro; Takase, Mitsuhiro; Majikina, Kensei; Yagasaki, Katsuma; Shinohara, Takeshi; Omori, Mamoru; Tomiyoshi, Shoichi; Akiba, Etsuo

    1998-07-01

    The oxygen content dependence of 63Cu NQR at the Cu(1) site and proton NMR have been measured in the antiferromagnetic phase of powdered samples of hydrogen-doped YBa2Cu3O6+xHy (0.07 NQR occur around 35 and 15 K, respectively. These enhancements increase with increasing oxygen concentration. The maximum values of T1-1 and T2-1 for the sample with x = 0.17 reach 200 sec-1 and more than 7 msec-1, respectively. The predominant source for the relaxation mechanism of 63Cu(l) NQR and the line broadening of 1H NMR are found to be the fluctuating magnetic field due to the staggered Cu2+ moments.

  5. In-Situ Characterization of Tissue Blood Flow, Blood Content, and Water State Using New Techniques in Magnetic Resonance Imaging.

    NASA Astrophysics Data System (ADS)

    Conturo, Thomas Edward

    Tissue blood flow, blood content, and water state have been characterized in-situ with new nuclear magnetic resonance imaging techniques. The sensitivities of standard techniques to the physiologic tissue parameters spin density (N_{rm r}) and relaxation times (T_1 and T_2 ) are mathematically defined. A new driven inversion method is developed so that tissue T_1 and T_2 changes produce cooperative intensity changes, yielding high contrast, high signal to noise, and sensitivity to a wider range of tissue parameters. The actual tissue parameters were imaged by automated collection of multiple-echo data having multiple T _1 dependence. Data are simultaneously fit by three-parameters to a closed-form expression, producing lower inter-parameter correlation and parameter noise than in separate T_1 or T_2 methods or pre-averaged methods. Accurate parameters are obtained at different field strengths. Parametric images of pathology demonstrate high sensitivity to tissue heterogeneity, and water content is determined in many tissues. Erythrocytes were paramagnetically labeled to study blood content and relaxation mechanisms. Liver and spleen relaxation were enhanced following 10% exchange of animal blood volumes. Rapid water exchange between intracellular and extracellular compartments was validated. Erythrocytes occupied 12.5% of renal cortex volume, and blood content was uniform in the liver, spleen and kidney. The magnitude and direction of flow velocity was then imaged. To eliminate directional artifacts, a bipolar gradient technique sensitized to flow in different directions was developed. Phase angle was reconstructed instead of intensity since the former has a 2pi -fold higher dynamic range. Images of flow through curves demonstrated secondary flow with a centrifugally-biased laminar profile and stationary velocity peaks along the curvature. Portal vein flow velocities were diminished or reversed in cirrhosis. Image artifacts have been characterized and removed. The foldover in magnified images was eliminated by exciting limited regions with orthogonal pi/2 and pi pulses. Off-midline regions were imaged by tandemly offsetting the phase-encoding and excitation. Artifacts due to non-steady-state conditions were demonstrated. The approach to steady state was defined by operators and vectors, and any repeated series of RF pulses was proven to produce a steady-state. The vector difference between the magnetization and its steady state value is relatively constant during the approach. The repetition time relative to T_1 is the main determinant of approach rate, and off-resonant RF pulses incoherent with the magnetization produce a more rapid approach than on-resonant pulses.

  6. A Novel Technique for Trimming the Frequency of a Sealed Surface Acoustic Wave Resonator

    Microsoft Academic Search

    J. A. Greer; T. E. Parker; M. Rothschild; D. J. Ehrlich

    1987-01-01

    An important requirement in many applications is the need to accurately set a SAW oscillator's frequency to a predetermined value. In some cases the oscillator's frequency may have to be set to within ?l PPM of a specified frequency which usually requires considerable time in external circuit adjustment. Recently, a novel post- seal frequency trimming technique has been developed for

  7. Monitoring of bystander effect of herpes simplex virus thymidine kinase/acyclovir system using fluorescence resonance energy transfer technique.

    PubMed

    Xiong, Tao; Li, Yongjun; Ni, Fenge; Zhang, Feng

    2012-02-01

    Cytotoxic gene therapy mediated by gene transfer of the herpes simplex virus thymidine kinase (HSV-tk) gene followed by acyclovir (ACV) treatment has been reported to inhibit malignant tumor growth in a variety of studies. The magnitude of "bystander effect" is an essential factor for this anti-tumor approach in vivo. However, the mechanism by which HSV-tk/ACV brings "bystander effect" is poorly understood. In this report, the plasmid CD3 (ECFP-CRS-DsRed) and TK-GFP were transferred to the human adenoid cystic carcinoma line ACC-M cell line. The CD3-expressing cells apoptosis was monitored using fluorescence resonance energy transfer (FRET) technique. First, CD3 and TK-GFP co-expressing ACC-M cells apoptosis was monitored using FRET technique. The apoptosis was induced by ACV and initiated by caspase3. The FRET efficient was remarkably decreased and then disappeared during cellular apoptosis, which indicated that the TK-GFP expressing ACC-M cells apoptosis, induced by ACV, was via a caspase3-dependent pathway. Secondly, CD3 and TK-GFP mixed expressing ACC-M cells apoptosis, induced by ACV, were monitored using FRET technique. The apoptotic phenomena appeared in the CD3-expressing ACC-M cells. The results show that HSV-tk/ACV system killed ACC-M cells using its bystander effect. These results confirm that HSV-tk/ACV system is potential for cancer gene therapy. PMID:22515095

  8. Penaeus orientolis prawn freshness rapid determination method based on electronic nose and non-linear stochastic resonance technique.

    PubMed

    Wei, Liu; Yuanyuan, Han; Yanping, Cai; Jiaojiao, Jin; Guohua, Hui

    2015-01-01

    In this paper, Penaeus orientolis prawn freshness rapid determination method using electronic nose (e-nose) and non-linear data processing technique is studied. E-nose responses to prawns stored at 4 °C are measured. Meanwhile, physical/chemical indexes (firmness, pH, total volatile basic nitrogen (TVB-N), total viable count (TVC), and human sensory evaluation) are examined to provide freshness references for e-nose analysis. E-nose measurement data is analyzed by principal component analysis (PCA), stochastic resonance (SR), and double-layered cascaded serial stochastic resonance (DCSSR). PCA partially discriminates prawns under different storage time. SR and DCSSR signal-to-noise ratio (SNR) spectrum eigen values discriminate prawns successfully. Multi-variables regressions (MVR) are conducted between physical/chemical indexes and SR/DCSSR output SNR minimal (SNR-Min) values. Results indicate that SNR-Min values present more significant linearity relation with physical/chemical indexes. Prawn freshness forecasting model is developed via Harris fitting regression on DCSSR SNR-Min values. Validating experiments demonstrate that forecasting accuracy of this model is 94.29%. PMID:25551520

  9. Inspiratory resonant frequency of forced oscillation technique as a predictor of the composite physiologic index in interstitial lung disease.

    PubMed

    Fujii, Masato; Shirai, Toshihiro; Mori, Kazutaka; Mikamo, Masashi; Shishido, Yuichiro; Akita, Takefumi; Morita, Satoru; Asada, Kazuhiro; Suda, Takafumi

    2015-02-01

    The composite physiologic index (CPI), which is derived from FEV1, FVC, and diffusing capacity, has been developed to predict the extent of fibrosis on high-resolution computed tomography (HRCT). However, the relevance to the forced oscillation technique (FOT) is not fully understood. We hypothesized that FOT would independently predict the CPI in interstitial lung disease (ILD). In this cross-sectional study we assessed the relationship between pulmonary function tests, forced oscillatory parameters, and the degree of fibrosis in ILD. Spirometry, evaluation of diffusing capacity for carbon monoxide, and the broadband frequency FOT were performed in 93 patients with a clinical/HRCT diagnosis of ILD. The CPI was calculated and fibrosis extent was measured by HRCT and scored. Univariate analyses revealed that, of the forced oscillatory parameters, inspiratory resonant frequency best correlated with FVC, FEV1, diffusing capacity, CPI, and fibrosis score. In multiple regression analyses, CPI was independently predicted by inspiratory resonant frequency and fibrosis score (model R(2)=0.405, p<0.0001). PMID:25514184

  10. A Wafer-Level Sn-Rich Au—Sn Bonding Technique and Its Application in Surface Plasmon Resonance Sensors

    NASA Astrophysics Data System (ADS)

    Mao, Xu; Lv, Xing-Dong; Wei, Wei-Wei; Zhang, Zhe; Yang, Jin-Ling; Qi, Zhi-Mei; Yang, Fu-Hua

    2014-05-01

    Sn-rich Au—Sn solder bonding is systematically investigated. High shear strength (64MPa) and good hermeticity (a leak rate lower than 1 × 10-7 torr·l/s) are obtained for Au—Sn solder with 54 wt% Sn bonded at 310°C. The AuSn2 phase with the highest Vickers-hardness among the four stable intermetallic compounds of the Au—Sn system makes a major contribution to the high bonding strength. This bonding technique has been successfully used to package the Surface Plasmon Resonance (SPR) sensors. The Sn-rich Au—Sn solder bonding provides a reliable, low-cost, low-temperature and wafer-level hermetic packaging solution for the micro-electromechanical system devices and has potential applications in high-end biomedical sensors.

  11. Quantitative description of aggregation and dissociation of polystyrene chains in cyclohexane solutions by resonance light scattering technique.

    PubMed

    Zhang, Wen Zhi; Chen, Xu Dong; Yang, Jin; Luo, Wei-ang; Zhang, Ming Qiu

    2010-01-28

    The resonance light scattering (RLS) technique based on a conventional fluorescence spectrophotometer was used to quantitatively describe the aggregation and dissociation of polystyrene (PS) in cyclohexane solution during cyclic heating and cooling. Transitions in conformation of PS molecules and aggregation of PS chains in the course of phase separation were revealed. The results indicated that PS chains changed from random coils to collapsed globules and then aggregated when temperature decreased. In contrast, when the system is heated, the chain aggregates were initially swelled and followed by gradual dissociation. Subsequently, the conformation of PS chains returned to the original state. Kinetics of phase separation of the PS solution was analyzed, which allowed estimation of the apparent activation energy. PMID:20044839

  12. Measurements of ocean surface spectrum from an aircraft using the two-frequency microwave resonance technique

    NASA Technical Reports Server (NTRS)

    Johnson, J. W.; Weissman, D. E.; Jones, W. L.

    1982-01-01

    The present investigation is concerned with the results of a two-frequency (Delta k) microwave radar experiment conducted from an aircraft and aimed primarily at the development of remote sensing techniques to measure ocean surface wave spectral characteristics. The experiment was conducted as part of the Maritime Remote Sensing (MARSEN) project in the North Sea during the autumn of 1979. The objective was to demonstrate the feasibility of and study the performance of the Delta k technique from a higher altitude platform, at shallower incidence angles, and at higher Doppler velocities than earlier stationary platform experiments allowed. A quantitative engineering evaluation of the results of two comprehensive flights is provided, and the qualitative significance of the results is discussed from a geophysical point of view in terms of the existing theory.

  13. Rapid and nondestructive determination of seed oil by pulsed nuclear magnetic resonance technique

    Microsoft Academic Search

    P. N. Tiwari; P. N. Gambhir; T. S. Rajan

    1974-01-01

    The pulsed NMR technique for rapid and nondestructive determination of oil in oilseeds has been developed. The effects of\\u000a spin-lattice relaxation time, spin-spin relaxation time, seed moisture, angular position of the seeds, sample tube thickness,\\u000a and sample height upon the magnitude and reproducibility of the NMR signal were studied. Based upon these studies, various\\u000a parameters for seed oil analysis have

  14. Nuclear magnetic resonance techniques for the structural characterization of siloxane–oxide hybrid materials

    Microsoft Academic Search

    Florence Babonneau; Jocelyne Maquet

    2000-01-01

    The objective of this paper is to discuss the appropriateness of various solution and solid state NMR techniques to describe structural aspects of siloxane–oxide hybrid systems prepared by sol-gel processes. Co-hydrolysis of organosilanes and metallic alkoxides can promote either self-condensation or co-condensation reactions between the different precursors, and this will control the structural homogeneity of the final network. Solution state

  15. Application of engineering analysis techniques to the design of magnetic resonance imaging (MRI) coils

    NASA Astrophysics Data System (ADS)

    Marin, L.; Power, H.; Bowtell, R. W.; Sanchez, C. C.; Becker, A. A.; Glover, P.; Jones, I. A.

    2008-03-01

    In this paper, we develop a new approach to analysing and designing the gradient coils for magnetic resonance imaging (MRI) scanners for medical applications. More specifically, a novel higher-order BEM which satisfies the continuity equation for the current density is proposed. We also present solution procedures for applying this method to the inverse problem whereby the divergence-free surface current distribution in the gradient coil is deduced from knowledge of the magnetic flux density in a prescribed region of interest. The novel BEM proposed is a non-traditional one, in the sense that the collocation points are given by the vertices of the triangular elements only and not all the BEM nodes used to define the boundary elements. Furthermore, the degree of the interpolation is one degree less than that of the geometry of the triangular elements employed, so that (for example) the linear boundary elements involve constant interpolation for the surface current density. Moreover, the present method can be easily extended in order to obtain any desired degree of the interpolation for the surface current density. Within the inverse problem, care must be taken to employ the optimal value of the Tikhonov regularisation parameter. Results are presented relating to various geometries of coil, obtained using linear, quadratic and cubic variants of the boundary element formulation; those obtained using the quadratic and cubic elements agree almost precisely, while those from the linear elements exhibit small differences from those of the higher-order formulations.

  16. Novel electro-optical coupling technique for magnetic resonance-compatible positron emission tomography detectors.

    PubMed

    Olcott, Peter D; Peng, Hao; Levin, Craig S

    2009-01-01

    A new magnetic resonance imaging (MRI)-compatible positron emission tomography (PET) detector design is being developed that uses electro-optical coupling to bring the amplitude and arrival time information of high-speed PET detector scintillation pulses out of an MRI system. The electro-optical coupling technology consists of a magnetically insensitive photodetector output signal connected to a nonmagnetic vertical cavity surface emitting laser (VCSEL) diode that is coupled to a multimode optical fiber. This scheme essentially acts as an optical wire with no influence on the MRI system. To test the feasibility of this approach, a lutetium-yttrium oxyorthosilicate crystal coupled to a single pixel of a solid-state photomultiplier array was placed in coincidence with a lutetium oxyorthosilicate crystal coupled to a fast photomultiplier tube with both the new nonmagnetic VCSEL coupling and the standard coaxial cable signal transmission scheme. No significant change was observed in 511 keV photopeak energy resolution and coincidence time resolution. This electro-optical coupling technology enables an MRI-compatible PET block detector to have a reduced electromagnetic footprint compared with the signal transmission schemes deployed in the current MRI/PET designs. PMID:19397853

  17. Vibrational pseudo-diffusive motion of the oxygen octahedra in La{sub 2}CuO{sub 4} and Sr doped La{sub 2}CuO{sub 4} from anelastic and {sup 139}La NQR relaxation

    SciTech Connect

    Cordero, F. [CNR, Roma (Italy)] [CNR, Roma (Italy); Campana, A.; Corti, M.; Rigamonti, A. [Unita INFM, Pavia (Italy)] [Unita INFM, Pavia (Italy); Cantelli, R. [Univ. di Roma La Sapienza (Italy). Dipt. di Fisica] [Univ. di Roma La Sapienza (Italy). Dipt. di Fisica; Ferretti, M. [Univ. di Genova (Italy). Dipt. di Chimica e Chimica Industriale] [Univ. di Genova (Italy). Dipt. di Chimica e Chimica Industriale

    1999-04-20

    The vibrational dynamics in nearly stoichiometric La{sub 2}CuO{sub 4+{delta}} has been studied by means of anelastic relaxation and by {sup 139}La NQR relaxation. Evidence of dynamical tilting of the octahedra in a double well local potential is obtained with both the experimental techniques. Anelastic relaxation at the quadrupole frequency {nu}{sub Q} {approximately} 19 MHz occurs at T {approximately} 330 K. The data are analyzed in terms of a model of pseudo-diffusive cooperative motion. The measured effective barrier is 2800 K, higher than the one of the local potential because of the cooperative character of the motion. Upon Sr doping the {sup 139}La relaxation is still dominated by the octahedra tilting waves for T > 100 K, while at low temperatures the magnetic relaxation mechanism related to Cu{sup 2+} spin fluctuation dominates. It is argued how the freezing of the tilts (occurring below 100 K in the undoped La{sub 2}CuO{sub 4}) might correspond to the formation of static stripes.

  18. Time-domain simulations of nonlinear interaction in microring resonators using finite-difference and coupled mode techniques.

    PubMed

    Shugayev, Roman; Bermel, Peter

    2014-08-11

    Nonlinear interactions within compact, on-chip microring resonant cavities is a topic of increasing interest in current silicon photonics research. Frequency combs, one of the emerging nonlinear applications in microring optics, offers great potential from both scientific and practical perspectives. However, the mechanisms of comb formation appear to differ from traditional frequency combs formed by pulsed femtosecond lasers, and thus require detailed elucidation through theory and simulation. Here we propose a technique to mimic the accuracy of finite-difference time domain (FDTD) full wave nonlinear optical simulations with only a small fraction of the computational resources. Our new hybrid approach combines a single linear FDTD simulation of the key interaction parameters, then directly inserts them into a coupled-mode theory simulation. Comparison of the hybrid approach and full FDTD shows a good match both in frequency domain and in time domain. Thus, it retains the advantage of FDTD in terms of direct connection with experimental designs, while finishing much faster and sidestepping stability issues associated with direct simulation of nonlinear phenomena. The hybrid technique produces several key results explored in this paper, including: demonstrating that comb formation can occur with both anomalous and normal dispersion; suggesting a new mechanism for incoherent (Type II) frequency comb formation; and illustrating a method for creating soliton-like pulses in on-chip microresonators. PMID:25321006

  19. Phosphorus nuclear magnetic resonance: a non-invasive technique for the study of muscle bioenergetics during exercise

    SciTech Connect

    Sapega, A.A.; Sokolow, D.P.; Graham, T.J.; Chance, B.

    1987-08-01

    Phosphorus nuclear magnetic resonance (/sup 31/P NMR) spectroscopy is a non-destructive analytical laboratory technique that, due to recent technical advances, has become applicable to the study of high-energy phosphate metabolism in both animal and human extremity muscles (in vivo). /sup 31/P NMR can assay cellular phosphocreatine, ATP, inorganic phosphate, the phosphorylated glycolytic intermediates, and intra-cellular pH in either resting or exercising muscle, in a non-invasive manner. NMR uses non-perturbing levels of radio-frequency energy as its biophysical probe and can therefore safely study intact muscle in a repeated fashion while exerting no artifactual influence on ongoing metabolic processes. Compared with standard tissue biopsy and biochemical assay techniques, NMR possesses the advantages of being non-invasive, allowing serial in situ studies of the same tissue sample, and providing measurements of only active (unbound) metabolites. NMR studies of exercising muscle have yielded information regarding fatigue mechanisms at the cellular level and are helping resolve long-standing questions regarding the metabolic control of glycolysis, oxidative phosphorylation, and post-exercise phosphocreatine re-synthesis. NMR is also being utilized to measure enzymatic reaction rates in vivo. In the near future, other forms of NMR spectroscopy may also permit the non-invasive measurement of tissue glycogen and lactate content. 75 references.

  20. Experimental Models of Brain Ischemia: A Review of Techniques, Magnetic Resonance Imaging, and Investigational Cell-Based Therapies

    PubMed Central

    Canazza, Alessandra; Minati, Ludovico; Boffano, Carlo; Parati, Eugenio; Binks, Sophie

    2013-01-01

    Stroke continues to be a significant cause of death and disability worldwide. Although major advances have been made in the past decades in prevention, treatment, and rehabilitation, enormous challenges remain in the way of translating new therapeutic approaches from bench to bedside. Thrombolysis, while routinely used for ischemic stroke, is only a viable option within a narrow time window. Recently, progress in stem cell biology has opened up avenues to therapeutic strategies aimed at supporting and replacing neural cells in infarcted areas. Realistic experimental animal models are crucial to understand the mechanisms of neuronal survival following ischemic brain injury and to develop therapeutic interventions. Current studies on experimental stroke therapies evaluate the efficiency of neuroprotective agents and cell-based approaches using primarily rodent models of permanent or transient focal cerebral ischemia. In parallel, advancements in imaging techniques permit better mapping of the spatial-temporal evolution of the lesioned cortex and its functional responses. This review provides a condensed conceptual review of the state of the art of this field, from models and magnetic resonance imaging techniques through to stem cell therapies. PMID:24600434

  1. An automatic method for detection and classification of Ionospheric Alfvén Resonances using signal and image processing techniques

    NASA Astrophysics Data System (ADS)

    Beggan, Ciaran

    2014-05-01

    Induction coils permit us to measure the very rapid changes of the magnetic field. In June 2012, the British Geological Survey Geomagnetism team installed two high frequency (100 Hz) induction coil magnetometers at the Eskdalemuir Observatory (55.3° N, 3.2° W, L~3), in the Scottish Borders of the United Kingdom. The Eskdalemuir Observatory is one of the longest running geophysical sites in the UK (beginning operation in 1908) and is located in a rural valley with a quiet magnetic environment. The coils record magnetic field changes over an effective frequency range of about 0.1-40Hz, and encompass phenomena such as the Schumann resonances, magnetospheric pulsations and Ionospheric Alfvén Resonances (IAR). In this study we focus on the IAR, which are related to the vibration of magnetic field lines passing through the ionosphere, believed to be mainly excited by lower atmospheric electrical discharges. The IAR typically manifest as a series of spectral resonances structures (SRS) within the 1-6Hz frequency range, usually appearing a fine bands or fringes in spectrogram plots. The SRS tend to occur daily between 18.00-06.00UT at the Eskdalemuir site, disappearing during the daylight hours. They usually start as a single low frequency before bifurcating into 5-10 separate fringes, increasing in frequency until around midnight. The fringes also widen in frequency before fading around 06.00UT. Occasionally, the fringes decrease in frequency slightly around 03.00UT before fading. In order to quantify the daily, seasonal and annual changes of the SRS, we developed a new method to identify the fringes and to quantify their occurrence in frequency (f) and the change in frequency (?f). The method uses short time-series of 100 seconds to produce an FFT spectral plot from which the non-stationary peaks are identified using the residuals from a best-fit six order spline. This is repeated for an entire day of data. The peaks from each time-slice are placed into a matrix which is then treated as an image. In combination with the spectrogram image of that day, the SRS are identified using image processing techniques. The peaks can now be mapped as continuous lines throughout the spectrogram. Finally, we can investigate the f and ?f statistics over the entire length of the dataset. We intend to run the coils as a long term experiment. The data and code are available on request.

  2. RECORD-HIGH RESOLUTION EXPERIMENTS ON COMPARISON OF SPIN PRECESSION FREQUENCIES OF ELECTRON BUNCHES USING THE RESONANT DEPOLARIZATION TECHNIQUE IN THE STORAGE RING

    Microsoft Academic Search

    O. Anchugov; V. Blinov; A. Bogomyagkov; V. Cherepanov; G. Karpov; V. Kiselev; E. Levichev; S. Nikitin; I. Nikolaev; A. Polunin; E. Shubin; E. Simonov; V. Smaluk; M. Struchalin; G. Tumaikin

    The opportunity of performing an experiment on CPT theorem test based on high precision comparison of the spin precession frequencies of electron and positrons mea- sured by the resonant depolarization technique in the stor- age ring is under study at the VEPP-4M facility.

  3. Compact and inexpensive frequency stabilization technique for 850-nm vertical cavity surface emitting lasers based on Fabry-Perot resonator

    NASA Astrophysics Data System (ADS)

    Miura, Yukio; Nakajima, Jun; Mizutani, Kouki; Sasaki, Wakao

    2007-09-01

    We have demonstrated a compact and inexpensive frequency stabilization technique for commercially available 1mW, 850nm vertical cavity surface emitting laser (VCSEL) using a Fabry-Perrot cavity as frequency standard. Recently VCSEL has been widely prevailed for uses of low cost and small sized sensors, since it may afford low power operations and manufacturing costs in comparison with edge emitting type Fabry-Perrot laser diodes. Therefore, a highly versatile and inexpensive frequency stabilized coherent light source which can be mass producible will be available if the frequency stabilization for this type of VCSEL's is carried out. Generally, it has been commonly accepted that a satisfactory degree of coherence may be easily obtained from VCSEL's without any additional frequency stabilization technique since highly reflective coatings are to be put on their laser cavity edges. Nevertheless, some VCSEL devices, especially inexpensive type commercial products show multi-mode behaviors along with polarization instabilities. In the present work, as a simple and inexpensive approach to commercially available VCSEL devices, we have demonstrated a frequency stabilization scheme using a Fabry-Perrot cavity. The error signal was derived by phase sensitive detection for the transmitted light from the Fabry-Perrot resonator. Thus, the lasing frequency of the VCSEL was locked to the zero-crossing of the error signal by negative feedback for injection current via a PID controller. As a result, we have successfully suppressed the amount of frequency fluctuations in the free-running VCSEL of as much as 2GHz to be within 500MHz at measuring time of 30sec, that is, the attained Allan variance is 4.1×10E-8.

  4. A comparative study of magnetic resonance venography techniques for the evaluation of the internal jugular veins in multiple sclerosis patients?

    PubMed Central

    Rahman, M. Tamizur; Sethi, Sean K.; Utriainen, David T.; Hewett, J. Joseph; Haacke, E. Mark

    2014-01-01

    Background and Purpose The use of magnetic resonance imaging (MRI) to assess the vascular nature of diseases such as multiple sclerosis (MS) is a growing field of research. This work reports on the application of MR angiographic (MRA) and venographic (MRV) techniques in assessing the extracranial vasculature in MS patients. Materials and Methods A standardized MRI protocol containing 2D TOF-MRV and dynamic 3D contrast-enhanced (CE) MRAV was run for 170 MS patients and 40 healthy controls (HC). The cross-sectional area (CSA) of the internal jugular veins (IJVs) was measured at three neck levels in all subjects for both MRV techniques to determine the presence of venous stenoses. All data were analyzed retrospectively. Results For the values where both methods showed signal, the 3D method showed larger CSA measurement values compared to 2D methods in both IJVs, in both MS and HC subjects which was confirmed with student paired t-tests. Of the 170 MS patients, 93 (55%) in CE-MRAV and 103 (61%) in TOF-MRV showed stenosis in at least one IJV. The corresponding numbers for the 40 HC subjects were 2 (5%) and 4 (10%), respectively. Carotid ectasias with IJV stenosis were seen in 26 cases (15%) with 3D CE-MRAV and were not observable with 2D TOF-MRV. Carotid ectasias were not seen in the HC group. In the 2D TOF-MRV data, banding of the IJVs related to slow flow was seen in 58 (34%) MS cases and in no HC cases. MS patients showed lower average CSAs than the HC subjects. Conclusion The 3D CE MRAV depicted the vascular anatomy more completely than the 2D TOF-MRV. However, the 3D CE MRAV does not provide any information about the flow characteristics which are indirectly available in the 2D TOF-MRV in those cases where there is slow flow. PMID:23850076

  5. Detection and quantification of on-chip phosphorylated peptides by surface plasmon resonance imaging techniques using a phosphate capture molecule.

    PubMed

    Inamori, Kazuki; Kyo, Motoki; Nishiya, Yoshiaki; Inoue, Yusuke; Sonoda, Tatsuhiko; Kinoshita, Eiji; Koike, Tohru; Katayama, Yoshiki

    2005-07-01

    We describe herein a detection and quantification system for on-chip phosphorylation of peptides by surface plasmon resonance (SPR) imaging techniques using a newly synthesized phosphate capture molecule (i.e., biotinylated zinc(II) complex). The biotinylated compound is a dinuclear zinc(II) complex that is suitable for accessing phosphate anions as a bridging ligand on the two zinc(II) ions. The compound was exposed on the peptide array and detected with streptavidin (SA) via a biotin-SA interaction by SPR imaging. In the conventional method using antibody, both anti-phosphoserine and anti-phosphotyrosine antibodies were required for phosphoserine and phosphotyrosine detection, respectively. Detection of the phosphate group by the zinc(II) complex, however, was independent of the phosphorylated amino acid residues. The calibration curve for the phosphorylation ratios was established with a calibration chip, on which phosphoserine-containing peptide probes were immobilized. The peptide probes, which were phosphorylated on the surface by protein kinase A, were detected and quantified by SPR imaging using the zinc(II) complex, SA, and anti-SA antibody. The reaction rate and the kinetics of on-chip phosphorylation were also evaluated with the peptide array. The phosphorylation ratio was saturated at approximately 20% in 2 h in this study. PMID:15987100

  6. Comparison of surface plasmon resonance spectroscopy and quartz crystal microbalance techniques for studying DNA assembly and hybridization.

    PubMed

    Su, Xiaodi; Wu, Ying-Ju; Knoll, Wolfgang

    2005-11-15

    In this study we evaluate the strengths and weaknesses of surface plasmon resonance (SPR) spectroscopy and quartz crystal microbalance (QCM) technique for studying DNA assembly and hybridization reactions. Specifically, we apply in parallel an SPR instrument and a 5 MHz QCM device with dissipation monitoring (QCM-D) to monitor the assembly of biotinylated DNA (biotin-DNA) on a streptavidin-modified surface and the subsequent target DNA hybridization. Through the parallel measurements, we demonstrate that SPR is more suitable for quantitative analysis of DNA binding amount, which is essential for interfacial DNA probe density control and for the analysis of its effect on hybridization efficiency and kinetics. Although the QCM is not quantitative to the same extent as SPR (QCM measures the total mass of the bound DNA molecules together with the associated water), the dissipation factor of the QCM provides a qualitative measure of the viscoelastic properties of DNA films and the conformation of the bound DNA molecules. The complexity in mass measurement does not impair QCM's potential for a kinetic evaluation of the hybridization processes. For quantification of target DNA, the biotin-DNA modified SPR and QCM sensors are exposed to target DNA with increasing concentration. The plots of SPR/QCM signals versus target DNA concentration show that water entrapment between DNA strands make the QCM sensitivity for the hybridization assay well comparable with that of the SPR, although the intrinsic mass sensitivity of the 5 MHz QCM is approximately 20 times lower. PMID:16242610

  7. Dislocation jump distances during creep of pure and doped NaCl single crystals using nuclear magnetic resonance pulse techniques

    NASA Astrophysics Data System (ADS)

    Murty, K. Linga; Kanert, O.

    1990-03-01

    Jump distances of dislocations are determined from the spin-lattice relaxation rates in a rotating frame [1/T1?] using in situ nuclear magnetic resonance pulse techniques during creep of pure and doped NaCl single crystals. Effects of divalent impurity and solid solution are investigated by doping with Ca and LiCl, respectively. Compression creep tests were performed at 10-30 MPa at 473 K. Relaxation rates were evaluated from spin-echo heights following ?/2, locking, and 64° pulse sequence. The amplitude of the spin echo decreased as soon as the load was applied following which it increased until the steady-state creep was reached, at which point a saturation value was observed. Mean jump distance of the mobile dislocations decreased with strain during the transient creep reaching a constant value at the onset and during the secondary creep. While the addition of 0.01 Ca has negligible influence on the jump distance, a solid solution with 0.01 LiCl resulted in about a four-fold increase. The results are compared and correlated with various microstructural parameters.

  8. NQR: a non-destructive method for studying oxygen content and defects in YBa 2Cu 3O 6+x superconducting thin films

    NASA Astrophysics Data System (ADS)

    Grévin, B.; Berthier, Y.; Pourtier, F.; Villégier, J. C.; Schmatz, U.

    1997-02-01

    NQR spectra of 63,65Cu isotopes were measured in YBa 2Cu 3O 6+x thin films at 1.4 K, which were prepared by cathodic sputtering and chemical vapor deposition. By comparison with powder spectra, we show that the films obtained by cathodic sputtering are overdoped. We discuss the possible reasons of the lower Tc commonly obtained in YBa 2Cu 3O 6+x thin films by comparison with powders and single crystals. Furthermore, we show that thin films synthesized by chemical vapor deposition could be affected by carbon retention.

  9. NMR and NQR study of the electronic and structural properties of Al-Cu-Fe and Al-Cu-Ru quasicrystals

    SciTech Connect

    Shastri, A.; Borsa, F.; Torgeson, D.R.; Shield, J.E.; Goldman, A.I. (Ames Laboratory, U.S. Department of Energy and Department of Physics Astronomy, Iowa State University, Ames, Iowa 50011 (United States))

    1994-12-01

    [sup 27]Al and [sup 63,65]Cu NMR is reported for powdered stable Al-Cu-Fe and Al-Cu-Ru icosahedral quasicrystals and crystalline approximants, and for an Al-Pd-Mn single-grain quasicrystal. [sup 27]Al NQR spectra at 4.2 K were observed in Al-Cu-Fe and Al-Cu-Ru samples. From quadrupole-perturbed NMR spectra at different magnetic fields, and from zero-field NQR spectra, a wide distribution of local electric-field gradient (EFG) tensor components and principal-axis-system orientations was found at the Al site. A model EFG calculation based on a 1/1 Al-Cu-Fe approximant successfully explained the observed NQR spectra. The average local gradient is largely determined by the [ital p]-electron wave function at the Al site, while the width of the distribution is due to EFG lattice contribution. Comparison of [sup 63]Cu and [sup 27]Al NMR shows the EFG distribution at the two sites is similar, but the electronic contribution to the EFG is considerably smaller at the Cu site, in agreement with a more [ital s]-type wave function of the conduction electrons. Overall spread of EFG values is well reproduced by calculation based on the approximant. However, the experimental spectra indicate a much larger number of nonequivalent sites when compared with the simulated NQR spectra based on the 1/1 approximant. The short-range, local chemical order is well represented by the approximant, but differences in coordination must be included at intermediate range in the quasicrystal. Measured [sup 27]Al Knight shift, magnetic susceptibility, and nuclear spin-lattice relaxation time as a function of temperature indicate reduced density of states at the Fermi level by a factor of 7 or 8 from the value in Al metal, consistent with the notion of a pseudogap for these quasicrystals. No differences in measured parameters were detected as a function of composition of the quasicrystalline alloys.

  10. Multipulse sequences for explosives detection by NQR under conditions of magnetoacoustic and piezoelectric ringing

    Microsoft Academic Search

    V. T. Mikhaltsevitch; T. N. Rudakov; J. H. Flexman; P. A. Hayes; W. P. Chisholm

    2004-01-01

    A number of methods for cancelling magnetoacoustic and piezoelectric ringing signals in the spectroscopy of the nuclear quadrupole\\u000a resonance are presented. The suggested methods include using the sequence (?0)?-(?-?x-2?-?\\u000a y\\u000a -2?-??x\\u000a -2?-??y\\u000a -?)\\u000a n\\u000a and a multipulse analog of the two-pulse Hahn sequence with the first pulse replaced by a short steady-state sequence. Another\\u000a method presented is the method of

  11. An isolated perfused pig heart model for the development, validation and translation of novel cardiovascular magnetic resonance techniques

    PubMed Central

    2010-01-01

    Background Novel cardiovascular magnetic resonance (CMR) techniques and imaging biomarkers are often validated in small animal models or empirically in patients. Direct translation of small animal CMR protocols to humans is rarely possible, while validation in humans is often difficult, slow and occasionally not possible due to ethical considerations. The aim of this study is to overcome these limitations by introducing an MR-compatible, free beating, blood-perfused, isolated pig heart model for the development of novel CMR methodology. Methods 6 hearts were perfused outside of the MR environment to establish preparation stability. Coronary perfusion pressure (CPP), coronary blood flow (CBF), left ventricular pressure (LVP), arterial blood gas and electrolyte composition were monitored over 4 hours. Further hearts were perfused within 3T (n = 3) and 1.5T (n = 3) clinical MR scanners, and characterised using functional (CINE), perfusion and late gadolinium enhancement (LGE) imaging. Perfusion imaging was performed globally and selectively for the right (RCA) and left coronary artery (LCA). In one heart the RCA perfusion territory was determined and compared to infarct size after coronary occlusion. Results All physiological parameters measured remained stable and within normal ranges. The model proved amenable to CMR at both field strengths using typical clinical acquisitions. There was good agreement between the RCA perfusion territory measured by selective first pass perfusion and LGE after coronary occlusion (37% versus 36% of the LV respectively). Conclusions This flexible model allows imaging of cardiac function in a controllable, beating, human-sized heart using clinical MR systems. It should aid further development, validation and clinical translation of novel CMR methodologies, and imaging sequences. PMID:20849589

  12. 139La nuclear magnetic resonance characterisation of La2O3 and La1-xSrxMO3 where M = Cr, Mn or Co.

    PubMed

    Bastow, T J

    1994-02-01

    139La Nuclear magnetic resonance (NMR) spectra have been used to obtain nuclear quadrupole coupling parameters for La2O3 and a series of perovskites La1-xSrxMO3 (where M = Cr, Mn or Co). Depending on the doping level of SrO2 these materials are either paramagnetic or ferromagnetic at room temperature. Magnetic transferred hyperfine effects are strongly in evidence in the Mn compounds. A 59Co NMR spectrum was observed in LaCoO3. A precision measurement of the nuclear quadrupole coupling constant in La2O3 was made by nuclear quadrupole resonance (NQR) spectroscopy. PMID:7827974

  13. Correlated Spin Dynamics and Phase Transitions in Pure and in Disordered 2D S = 1/2 Antiferromagnets: Insights from NMR-NQR

    NASA Astrophysics Data System (ADS)

    Rigamonti, A.; Carretta, P.; Papinutto, N.

    A recall of the phase diagram for two-dimensional quantum Heisenberg antiferromagnets (2DQHAF) and of the main issues involving phase transitions and spin dynamics in these systems is first given. After a pedagogical description of the basic aspects for the NMR-NQR relaxation rates in terms of amplitudes and decay rates of spin fluctuations, the problem of the temperature dependence of the correlation length in prototype, pure 2DQHAF (CFTD and La2CuO4) is addressed. Then spin- and charge-doped systems (Zn/Mg for Cu and Sr for La substitutions in La2CuO4) are considered and the effects on the spin stiffness, on the correlation length and on the staggered Cu2+ magnetic moment are reported, in particular near the percolation threshold. A critical outline of the properties of the cluster spin glass phase in Sr- doped La2CuO4 is given. Finally the results of a 63Cu NQR-NMR relaxation study around the quantum critical point (in CeCu6-xAux) are presented. It is pointed out how the 2D response function with anomalous exponent and energy/ temperature scaling indicated by neutron scattering is basically confirmed, while the 63Cu relaxation measurements reveal novel effects involving low-energy spin excitations and the role of an external magnetic field.

  14. Study of the interaction of nucleic acids with acridine red and CTMAB by a resonance light scattering technique and determination of nucleic acids at nanogram levels

    Microsoft Academic Search

    Min Wang; Jinghe Yang; Xia Wu; Fang Huang

    2000-01-01

    In this paper, a determinating method of nucleic acids at nanogram levels by a resonance light scattering (RLS) technique with a common spectrofluorometer has been reported. The characteristics of RLS spectra of acridine red (AR) with nucleic acids, the effective factors and the optimum conditions have been studied. In the pH range 6.40–7.10, nucleic acids and surfactant CTMAB can jointly

  15. Precision fabrication techniques and analysis on high-Q evanescent-mode resonators and filters of different geometries

    Microsoft Academic Search

    Xun Gong; Alexandros Margomenos; Bosui Liu; Shloke Hajela; Linda P. B. Katehi; William J. Chappell

    2004-01-01

    High-Q evanescent-mode resonators and filters are realized by both silicon micromachining and layer-by-layer polymer processing. Capacitively loaded cavities can be reduced to a size much smaller than a wavelength, but still have a much higher unloaded Q than lumped elements. The loaded resonators are utilized for reduced-size filters with a low insertion loss enabled by the relatively high-Q factor. The

  16. Comparison of TOF-ERDA and nuclear resonance reaction techniques for range profile measurements of keV energy implants

    Microsoft Academic Search

    J. Jokinen; J. Keinonen; P. Tikkanen; A. Kuronen; T. Ahlgren; K. Nordlund

    1996-01-01

    A comparative study on the range measurements of keV energy implants by the Time-of-Flight Elastic Recoil Detection Analysis (TOF-ERDA) and conventionally used nuclear resonance reaction methods has been performed for 20–100 keV 15N+ ions implanted into crystalline silicon. Range profiles of 15N atoms were chosen because they can be measured accurately using a very strong and narrow resonance at Ep

  17. Quantitative linear and nonlinear resonance inspection techniques and analysis for material characterization: application to concrete thermal damage.

    PubMed

    Payan, C; Ulrich, T J; Le Bas, P Y; Saleh, T; Guimaraes, M

    2014-08-01

    Developed in the late 1980s, Nonlinear Resonant Ultrasound Spectroscopy (NRUS) has been widely employed in the field of material characterization. Most of the studies assume the measured amplitude to be proportional to the strain amplitude which drives nonlinear phenomena. In 1D resonant bar experiments, the configuration for which NRUS was initially developed, this assumption holds. However, it is not true for samples of general shape which exhibit several resonance mode shapes. This paper proposes a methodology based on linear resonant ultrasound spectroscopy, numerical simulations and nonlinear resonant ultrasound spectroscopy to provide quantitative values of nonlinear elastic moduli taking into account the 3D nature of the samples. In the context of license renewal in the field of nuclear energy, this study aims at providing some quantitative information related to the degree of micro-cracking of concrete and cement based materials in the presence of thermal damage. The resonance based method is validated as regard with concrete microstructure evolution during thermal exposure. PMID:25096088

  18. NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts

    SciTech Connect

    Not Available

    1991-12-17

    Our previous studies (1,2) on the zerofield NMR spectra of Cu/Co catalysts revealed that the method of preparation sensitively influences the magnetic character of the Catalyst. Catalytic studies of the earlier investigators also (3) show similar influence on the product selectivity and indicate reproducible performance is critically dependent on the control and rigor of the preparation technique. To compliment the NMR results, we have made a thorough investigation of the Hysteresis character of the Cu/Co catalysts with the metal ratio varying from 0.2 to 4.0.

  19. Note: Matching index technique for avoiding higher order mode resonance in accelerators: INDUS-2 accelerator as a case study

    SciTech Connect

    Jain, V.; Joshi, S. C. [Raja Ramanna Centre for Advanced Technology, RRCAT, Indore 452013 (India)] [Raja Ramanna Centre for Advanced Technology, RRCAT, Indore 452013 (India); Bhandarkar, U. V. [Department of Mechanical Engineering, Indian Institute of Technology Bombay, Powai 400076, Mumbai (India)] [Department of Mechanical Engineering, Indian Institute of Technology Bombay, Powai 400076, Mumbai (India); Krishnagopal, S. [Bhabha Atomic Research Centre, Mumbai 400085 (India) [Bhabha Atomic Research Centre, Mumbai 400085 (India); Centre for Excellence in Basic Sciences, Mumbai 400098 (India)

    2013-08-15

    Resonance between circulating beam frequencies and RF cavity Higher Order Modes (HOMs) of accelerators can lead to coupled-bunch instabilities. Shifting these HOMs to avoid the resonance is a topic of active interest. A study has been carried out for the accelerating cavities of the INDUS-2. For quantitative measure of deciding which modes have to be moved and by how much, we introduce a new index called the matching index (I{sub M}), as a measure of how close a HOM is to the nearest beam mode. Depending on the value of I{sub M}, the operating scenarios are classified as safe and unsafe.

  20. Improved L-C resonant decay technique for Q measurement of quasilinear power inductors: New results for MPP and ferrite powdered cores

    NASA Technical Reports Server (NTRS)

    Niedra, Janis M.; Gerber, Scott S.

    1995-01-01

    The L-C resonant decay technique for measuring circuit Q or losses is improved by eliminating the switch from the inductor-capacitor loop. A MOSFET switch is used instead to momentarily connect the resonant circuit to an existing voltage source, which itself is gated off during the decay transient. Very reproducible, low duty cycle data could be taken this way over a dynamic voltage range of at least 10:1. Circuit Q is computed from a polynomial fit to the sequence of the decaying voltage maxima. This method was applied to measure the losses at 60 kHz in inductors having loose powder cores of moly permalloy and an Mn-Zn power ferrite. After the copper and capacitor losses are separated out, the resulting specific core loss is shown to be roughly as expected for the MPP powder, but anomalously high for the ferrite powder. Possible causes are mentioned.

  1. In vivo electron spin resonance-computed tomography\\/nitroxyl probe technique for non-invasive analysis of oxidative injuries

    Microsoft Academic Search

    Hideo Utsumi; Ken-ichi Yamada

    2003-01-01

    Free radicals are widely recognized as harmful chemical species in oxidative tissue injury. However, there have been no satisfying methods to visualize free radicals in vivo non-invasively with information of their localization and amount. In vivo electron spin resonance (ESR) spectroscopy was recently developed to measure free radicals generated in rodents. Several kinds of stable nitroxyl radicals were used as

  2. Diffusive contribution to permeation of hydrogel contact lenses: theoretical model and experimental evaluation by nuclear magnetic resonance techniques

    Microsoft Academic Search

    Cesare Manetti; Lorena Casciani; Nicola Pescosolido

    2002-01-01

    The biocompatibility of contact lenses is closely related to their oxygen permeability. In hydrogel lenses, this characteristic can be attributed to the water permeability resulting from a combination of viscous and diffusive fluxes. Hydrogel lenses were studied by means of nuclear magnetic resonance (NMR) relaxation times, resulting in a mathematical model which evaluated the water self-diffusion coefficient as a quantification

  3. Electronic resonance enhanced coherent anti-Stokes Raman scattering technique for detection of combustion species and biological molecules 

    E-print Network

    Hanna, Sherif Fayez

    2006-10-30

    The application of electronic-resonance enhanced (ERE) coherent anti-Stokes Raman scattering (CARS) for the detection of nitric oxide (NO) and acetylene (C2H2) is experimentally demonstrated and the effects of various parameters on the ERE CARS...

  4. Electronic resonance enhanced coherent anti-Stokes Raman scattering technique for detection of combustion species and biological molecules

    E-print Network

    Hanna, Sherif Fayez

    2006-10-30

    The application of electronic-resonance enhanced (ERE) coherent anti-Stokes Raman scattering (CARS) for the detection of nitric oxide (NO) and acetylene (C2H2) is experimentally demonstrated and the effects of various parameters on the ERE CARS...

  5. Nuclear quadrupole resonance of barium in BaBiO3 and BaPbO3

    NASA Astrophysics Data System (ADS)

    Savosta, M. M.; Doroshev, V. D.; Borodin, V. A.; Pashkevich, Yu. G.; Kamenev, V. I.; Tarasenko, T. N.; Englich, J.; Kohout, J.; Soldatov, A. G.; Barilo, S. N.; Shiryaev, S. V.

    2001-05-01

    The nuclear quadrupole resonance (NQR) on Ba nuclei was studied in four samples of BaBiO3 prepared in different ways and, in addition, in BaPbO3. The spectrum of 137Ba at T=4.2 K consists of a relatively broad line centered near 18 MHz for all BaBiO3 samples and near 13 MHz for BaPbO3. The integrated intensity of the 137Ba resonance in the ceramic sample of BaBiO3 synthesized at 800 °C is approximately twice as large as that in ceramic samples and a single crystal prepared at 930-1080 °C. The decrease of the NQR signal can be attributed to the partial disordering of charge-disproportionated Bi ions on the two inequivalent sites. The broadening of the resonance indicates that local distortions of the crystal structure exist in both compounds. The point-charge model was used to analyze the electric-field gradient on the Ba sites.

  6. Picosecond-switching time of In0.53Ga0.47As\\/AlAs resonant-tunneling diodes measured by electro-optic sampling technique

    Microsoft Academic Search

    Naofumi Shimizu; Tadao Nagatsuma; Mitsuru Shinagawa; Takao Waho

    1995-01-01

    To demonstrate picosecond-switching time for In0.53Ga 0.47As\\/AlAs resonant-tunneling diodes (RTD's), we fabricated RTD's with various barrier widths and measured their switching times using electro-optic sampling technique specially arranged for RTD's with high current density. For an RTD having the barrier width of 1.4 nm with the peak current density of 4.5×105 A\\/cm2 and peak-to-valley ratio of 3.9, the switching time

  7. Elastic properties of composites: periodical homogenisation technique and experimental comparison using acoustic microscopy and resonant ultrasonic spectroscopy.

    PubMed

    Laux, D; Ferrandis, J Y; Leveque, G; Gatt, J M

    2006-12-01

    The macroscopic elastic properties of two composites (Duralumin/air and Duralumin/tungsten carbide (WC)) have been calculated using periodical homogenisation methods and the elastic properties of each phase (measured by high frequency acoustic microscopy). In order to check the validity of such an approach, acoustical resonant spectroscopy has also been applied. Thanks to the comparison between the resonant frequencies predicted and measured, two major conclusions have been obtained: the homogenisation method is very accurate for the composite Duralumin/air, but not for the Duralumin/WC sample: the experimental results are not in very good agreement with the simulation. This result can be then explained by the major role of interfacial state between Duralumin and tungsten carbide. PMID:16949116

  8. Determination of nucleic acids at nanogram levels with safranine T by a resonance light-scattering technique

    Microsoft Academic Search

    Cheng Zhi Huang; Yuan Fang Li; Xi Dong Liu

    1998-01-01

    This is the first report of the determination of nucleic acids based on their template roles for long range assembly of organic dyes. At pH 7.05 and ionic strength 0.0045, the interactions of safranine T (ST) with nucleic acids result in three characteristic peaks of resonance light scattering (RLS) at 328.0, 472.0 and 572.0nm. Mechanistic studies show that these peaks

  9. Comparison of DNA, aminoethylglycyl PNA and pyrrolidinyl PNA as probes for detection of DNA hybridization using surface plasmon resonance technique

    Microsoft Academic Search

    Cheeraporn Ananthanawat; Tirayut Vilaivan; Voravee P. Hoven; Xiaodi Su

    2010-01-01

    Pyrrolidinyl peptide nucleic acid bearing a d-prolyl-2-aminocyclopentanecarboxylic acid backbone (acpcPNA) has been evaluated as a new sensing probe for detection of DNA hybridization. In this study, the biotinylated acpcPNA was immobilized on surface plasmon resonance (SPR) sensor chips via biotin–streptavidin interactions for solid-phase DNA hybridization. A critical comparison between acpcPNA, DNA and conventional peptide nucleic acid (aegPNA) probes of the

  10. Noninvasive angiography (magnetic resonance and computed tomography) in the diagnosis of ischemic cerebrovascular disease. Techniques and clinical applications.

    PubMed

    Schellinger, Peter D; Richter, Gregor; Kohrmann, Martin; Dorfler, Arnd

    2007-01-01

    Noninvasive diagnostic imaging of the craniocervical and intracranial vasculature is a domain of computed tomography angiography (CTA), magnetic resonance angiography (MRA) and Doppler/duplex ultrasound, the latter not being the topic of this presentation. We give a methodological background for both, CTA and MRA, followed by a critical appraisal of both imaging modalities in the diagnosis of ischemic cerebrovascular disease. The contribution of noninvasive vascular imaging to vascular malformations (including aneurysms, fistulas and cerebral-vein thrombosis) is beyond the scope of this paper and therefore not covered. PMID:17971635

  11. Identification of Field Line Resonances in the Magnetosphere Using the Super Dual Auroral Radar Network (superdarn): New ``CROSS-POWER and Cross-Phase Technique

    NASA Astrophysics Data System (ADS)

    Mazzino, L.; Fenrich, F. R.

    2010-12-01

    Field Line Resonances (FLRs) are Ultra Low Frequency (ULF) standing waves that appear in discrete frequencies and occur in Earth’s Magnetic Field as a result of wave coupling of MHD compressional and Shear Alfvén waves. The main purpose of the new ‘cross-power and cross-phase’ technique, presented in this analysis, is to systematically identify FLR occurrence using data from the Super Dual Auroral Radar Network (SuperDARN), a radar network that detects coherent echoes from plasma irregularities that are aligned with the field lines. SuperDARN data has been successfully used for more than 17 years to identify FLRs, due to its large coverage over the polar cap and auroral region. Specifications of the instrument as well as the algorithm used by this new technique will be explained in detail. As an example we will apply the technique to a known 1.9 mHz FLR that occurred on November 20th 2003 at 22:30-23:00 UT detected by the Prince George station. Discussion of the application of this technique to automatically detect other events, and the future statistical analysis of all events identified will be presented.

  12. Detection and identification of underwater targets by resonance or resonant scattering

    Microsoft Academic Search

    Gee-In Goo

    1997-01-01

    This paper presents the resonance or resonant scattering technique for detection and identification of underwater targets. Based on the resonance theory and the resonant scattering theory (RST), all underwater objects resonate at their natural frequencies when impinged by acoustic energy. These resonating natural frequencies appear as modulations on the frequency domain of the target echoes. Since these natural resonances are

  13. Technique for a hybrid system of real-time transrectal ultrasound with preoperative magnetic resonance imaging in the guidance of targeted prostate biopsy.

    PubMed

    Ukimura, Osamu; Hirahara, Naoki; Fujihara, Atsuko; Yamada, Takeshi; Iwata, Tsuyoshi; Kamoi, Kazumi; Okihara, Koji; Ito, Hirotoshi; Nishimura, Tsunehiko; Miki, Tsuneharu

    2010-10-01

    Diagnostic magnetic resonance imaging (MRI) for prostate has achieved increasingly higher levels of accuracy. Because real-time MR-guided targeted biopsy is still a complicated and expensive procedure, there is considerable interest in a technique of MR/transrectal ultrasound (TRUS) hybridized image-guided biopsy. However, because the 3-D shapes of the prostate at the time of image-acquisition at preoperative MRI are likely to be different from the intra-operative TRUS images, the precise registration of each 3-D volume data is critical. To reduce the potential errors in registration of TRUS with MRI, we introduce new procedural techniques in a rigid image fusion technique. First, preoperative MR images were obtained with a specifically-made plastic outer-frame, with exactly the same shape as the real TRUS probe, placed in the rectum, in order to simulate the deformation of the prostate caused by the absence or presence of a TRUS probe during the acquisition of MR or TRUS images. Second, instead of using a single plane of longitudinal image, we applied biplane TRUS images to be shown in parallel on a multiplanar display with corresponding reconstructed MRI, in order to register both horizontal and longitudinal images of the prostate simultaneously, thereby achieving improved 3-D anatomical matching. PMID:20812938

  14. Sensitivity of the curve-to-growth technique utilized in rocket experiments to determine the line shape of solar He I resonance lines

    NASA Technical Reports Server (NTRS)

    Wu, C. Y. R.; Ogawa, H. S.

    1986-01-01

    The sensitivity of the curve-of-growth (COG) technique utilized in rocket measurements to determine the line profiles of the solar He I resonance emissions is theoretically examined with attention to the possibility of determining the line core shape using this technique. The line at 584.334 A is chosen as an illustration. Various possible source functions of the solar line have been assumed in the computation of the integrated transmitted intensity. A recent observational data set obtained by the present researchers is used as the constraint of the computation. It is confirmed that the COG technique can indeed provide a good measurement of the solar line width. However, to obtain detailed knowledge of the solar profile at line center and in the core region, (1) it is necessary to be able to carry out relative solar flux measurements with a 1-percent or better precision, and (2) it must be possible to measure the He gas pressure in the absorption cell to lower than 0.1 mtorr. While these numbers apply specifically to the present geometry, the results are readily scaled to other COG measurements using other experimental parameters.

  15. Nuclear magnetic resonance with dc SQUID (Super-conducting QUantum Interference Device) preamplifiers

    SciTech Connect

    Fan, N.Q.; Heaney, M.B.; Clark, J.; Newitt, D.; Wald, L.; Hahn, E.L.; Bierlecki, A.; Pines, A.

    1988-08-01

    Sensitive radio-frequency (rf) amplifiers based on dc Superconducting QUantum Interface Devices (SQUIDS) are available for frequencies up to 200 MHz. At 4.2 K, the gain and noise temperature of a typical tuned amplifier are 18.6 +- 0.5 dB and 1.7 +- 0.5 K at 93 MHz. These amplifiers are being applied to a series of novel experiments on nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR). The high sensitivity of these amplifiers was demonstrated in the observation of ''nuclear spin noise'', the emission of photons by /sup 35/Cl nuclei in a state of zero polarization. In the more conventional experiments in which one applies a large rf pulse to the spins, a Q-spoiler, consisting of a series array of Josephson junctions, is used to reduce the Q of the input circuit to a very low value during the pulse. The Q-spoiler enables the circuit to recover quickly after the pulse, and has been used in an NQR experiment to achieve a sensitivity of about 2 /times/ 10/sup 16/ nuclear Bohr magnetons in a single free precession signal with a bandwidth of 10 kHz. In a third experiment, a sample containing /sup 35/Cl nuclei was placed in a capacitor and the signal detected electrically using a tuned SQUID amplifier and Q-spoiler. In this way, the electrical polarization induced by the precessing Cl nuclear quadrupole moments was detected: this is the inverse of the Stark effect in NQR. Two experiments involving NMR have been carried out. In the first, the 30 MHz resonance in /sup 119/Sn nuclei is detected with a tuned amplifier and Q-spoiler, and a single pulse resolution of 10/sup 18/ nuclear Bohr magnetons in a bandwidth of 25 kHz has been achieved. For the second, a low frequency NMR system has been developed that uses an untuned input circuit coupled to the SQUID. The resonance in /sup 195/Pt nuclei has been observed at 55 kHz in a field of 60 gauss. 23 refs., 11 figs.

  16. Application of Polypyrrole Multi-Walled Carbon Nanotube Composite Layer for Detection of Mercury, Lead and Iron Ions Using Surface Plasmon Resonance Technique

    PubMed Central

    Sadrolhosseini, Amir Reza; Noor, A. S. M.; Bahrami, Afarin; Lim, H. N.; Talib, Zainal Abidin; Mahdi, Mohd. Adzir

    2014-01-01

    Polypyrrole multi-walled carbon nanotube composite layers were used to modify the gold layer to measure heavy metal ions using the surface plasmon resonance technique. The new sensor was fabricated to detect trace amounts of mercury (Hg), lead (Pb), and iron (Fe) ions. In the present research, the sensitivity of a polypyrrole multi-walled carbon nanotube composite layer and a polypyrrole layer were compared. The application of polypyrrole multi-walled carbon nanotubes enhanced the sensitivity and accuracy of the sensor for detecting ions in an aqueous solution due to the binding of mercury, lead, and iron ions to the sensing layer. The Hg ion bonded to the sensing layer more strongly than did the Pb and Fe ions. The limitation of the sensor was calculated to be about 0.1 ppm, which produced an angle shift in the region of 0.3° to 0.6°. PMID:24733263

  17. Following the transient reactions in lithium-sulfur batteries using an in situ nuclear magnetic resonance technique.

    PubMed

    Xiao, Jie; Hu, Jian Zhi; Chen, Honghao; Vijayakumar, M; Zheng, Jianming; Pan, Huilin; Walter, Eric D; Hu, Mary; Deng, Xuchu; Feng, Ju; Liaw, Bor Yann; Gu, Meng; Deng, Zhiqun Daniel; Lu, Dongping; Xu, Suochang; Wang, Chongmin; Liu, Jun

    2015-05-13

    A fundamental understanding of electrochemical reaction pathways is critical to improving the performance of Li-S batteries, but few techniques can be used to directly identify and quantify the reaction species during disharge/charge cycling processes in real time. Here, an in situ (7)Li NMR technique employing a specially designed cylindrical microbattery was used to probe the transient electrochemical and chemical reactions occurring during the cycling of a Li-S system. In situ NMR provides real time, semiquantitative information related to the temporal evolution of lithium polysulfide allotropes during both discharge/charge processes. This technique uniquely reveals that the polysulfide redox reactions involve charged free radicals as intermediate species that are difficult to detect in ex situ NMR studies. Additionally, it also uncovers vital information about the (7)Li chemical environments during the electrochemical and parasitic reactions on the Li metal anode. These new molecular-level insights about transient species and the associated anode failure mechanism are crucial to delineating effective strategies to accelerate the development of Li-S battery technologies. PMID:25785550

  18. Usefulness of two-point Dixon fat-water separation technique in gadoxetic acid-enhanced liver magnetic resonance imaging

    PubMed Central

    Ding, Ying; Rao, Sheng-Xiang; Chen, Cai-Zhong; Li, Ren-Chen; Zeng, Meng-Su

    2015-01-01

    AIM: To compare differences between volumetric interpolated breath-hold examination (VIBE) using two-point Dixon fat-water separation (Dixon-VIBE) and chemically selective fat saturation (FS-VIBE) with magnetic resonance imaging examination. METHODS: Forty-nine patients were included, who were scanned with two VIBE sequences (Dixon-VIBE and FS-VIBE) in hepatobiliary phase after gadoxetic acid administration. Subjective evaluations including sharpness of tumor, sharpness of vessels, strength and homogeneity of fat suppression, and artifacts that were scored using a 4-point scale. The liver-to-lesion contrast was also calculated and compared. RESULTS: Dixon-VIBE with water reconstruction had significantly higher subjective scores than FS-VIBE in strength and homogeneity of fat suppression (< 0.0001) but lower scores in sharpness of tumor (P < 0.0001), sharpness of vessels (P = 0.0001), and artifacts (P = 0.034). The liver-to-lesion contrast on Dixon-VIBE images was significantly lower than that on FS-VIBE (16.6% ± 9.4% vs 23.9% ± 12.1%, P = 0.0001). CONCLUSION: Dixon-VIBE provides stronger and more homogenous fat suppression than FS-VIBE, while has lower clarity of focal liver lesions in hepatobiliary phase after gadoxetic acid administration. PMID:25945017

  19. Graphene quantum dots and the resonance light scattering technique for trace analysis of phenol in different water samples.

    PubMed

    Sun, Ruiling; Wang, Yong; Ni, Yongnian; Kokot, Serge

    2014-07-01

    A novel, highly selective resonance light scattering (RLS) method was researched and developed for the analysis of phenol in different types of industrial water. An important aspect of the method involved the use of graphene quantum dots (GQDs), which were initially obtained from the pyrolysis of citric acid dissolved in aqueous solutions. The GQDs in the presence of horseradish peroxidase (HRP) and H2O2 were found to react quantitatively with phenol such that the RLS spectral band (310 nm) was quantitatively enhanced as a consequence of the interaction between the GQDs and the quinone formed in the above reaction. It was demonstrated that the novel analytical method had better selectivity and sensitivity for the determination of phenol in water as compared to other analytical methods found in the literature. Thus, trace amounts of phenol were detected over the linear ranges of 6.00×10(-8)-2.16×10(-6)M and 2.40×10(-6)-2.88×10(-5)M with a detection limit of 2.20×10(-8)M. In addition, three different spiked waste water samples and two untreated lake water samples were analysed for phenol. Satisfactory results were obtained with the use of the novel, sensitive and rapid RLS method. PMID:24840454

  20. A highly sensitive assay for protein using resonance light-scattering technique with dibromohydroxyphenylfluorone-molybdenum(VI) complex.

    PubMed

    Guo, Z X; Shen, H X

    1999-12-01

    At pH 2.8 and in the presence of 0.090% p-octylpolyethyleneglycol phenylether, the resonance light-scattering (RLS) spectrum of molybdenum(VI) complex with dibromohydroxyphenylfluorone (DBHPF) has a sharp peak at 586 nm. If the micro protein coexists with Mo(VI) and DBHPF, the RLS intensity of the complex at 586 nm is significantly enhanced by protein due to the binding interaction between protein and DBHPF-Mo(VI) complex. Based on this a new assay for protein is described. The dynamic ranges for bovine and human serum albumins are both 0.05-0.75 mg l-1 with detection limits of 13 and 15 ng ml-1, respectively. Besides high sensitivity, the method is characterized by good reproducibility, rapidity of reaction, good stability of chemical system, commonality of spectrofluorometer, few coexisting substances, especially detergents. The determinations of diluted human serum and urine by this method give the results very close to these by the Coomassie brilliant blue G-250 colorimetry, with relative standard deviations of five duplicates of 1.8-2.5%. PMID:10659451

  1. Rate constant for the reaction H + NO2 from 195 to 400 K with FP-RF and DF-RF techniques. [Flash Photolysis and Discharge Flow-Resonance Fluorescence

    NASA Technical Reports Server (NTRS)

    Michael, J. V.; Nava, D. F.; Payne, W. A.; Lee, J. H.; Stief, L. J.

    1979-01-01

    Measurements are made of the rate constant for the reaction H + NO2 yielding OH + NO over significant temperature ranges with the flash photolysis-resonance fluorescence (FP-RF) technique and also with the discharge flow-resonance fluorescence (DF-RF) technique. Since it is important to study chemical reactions with more than one technique, the above reaction is investigated with the FP-RF technique over the temperature range 230-400 K. The results reported do not agree with earlier determinations. Accordingly, a separate set of measurements is made with the DF-RF technique over the temperature range 195-368 K; the results are also reported. The reaction is also considered theoretically, especially with regard to the question of temperature dependence and absolute magnitude of the rate constant.

  2. NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts. Quarterly technical progress report, September 14--December 15, 1990

    SciTech Connect

    Not Available

    1991-01-14

    Copper and cobalt are the key elements in syngas conversion catalyst systems used for higher alcohol synthesis. Their proximity and synergy sensitively control the selectivity and efficiency of the process. It is believed that their outer electronic charge distribution which is responsible for their electrical and magnetic properties might be governing their catalytic properties also. To examine the correlation between catalytic and magnetic properties, a series of copper cobalt catalysts (Co/Cu ratio 5:1 to 5:5) with and without a support were prepared. The nuclear quadrupole resonance spectrum of copper and (zero-field) nuclear magnetic resonance spectrum of cobalt and magnetization and hysteresis character of the catalyst were analyzed. Similar to the catalytic results, the magnetic results also were found to be very sensitive to the preparation technique. The results indicate possible electron exchange between copper and cobalt, and cobalt and the support Titania.

  3. Treatment of subclinical hyperthyroidism: effect on left ventricular mass and function of the heart using magnetic resonance imaging technique

    PubMed Central

    Mark, Peter D; Andreassen, Mikkel; Petersen, Claus L; Kjaer, Andreas; Faber, Jens

    2015-01-01

    Purpose The aim of this study was to investigate structure and function of the heart in subclinical hyperthyroidism (SH) before and after obtaining euthyroidism by radioactive iodine treatment, using high precision and observer-independent magnetic resonance imaging (MRI) technology. Methods Cardiac MRI was performed before and after euthyroidism was obtained by radioactive iodine treatment in 12 otherwise healthy patients (11 women and one man, mean age 59 years, range 44–71 years) with a nodular goiter and SH, and compared with eight healthy controls investigated at baseline. Cardiac data were expressed as an index, as per body surface area, except for heart rate (HR) and ejection fraction. Results Post-treatment cardiac MRI was performed in median 139 days after a normalized serum TSH value had been recorded. During treatment, serum TSH increased from (median (range)) 0.01 (0.01–0.09) to 0.88 (0.27–3.99) mU/l. Patients with untreated SH had increased resting HR (P<0.01) as well as cardiac index (cardiac output as per body surface area) (P<0.01) compared with controls. Obtaining euthyroidism resulted in a significant decrease in left ventricular mass index (LVMI) of 2.7?g/m2 (P=0.034), in HR of 8?bpm (P=0.001), and in cardiac index of 0.24?l/min per m2 (P=0.017). Conclusions Normalization of thyroid function by radioactive iodine treatment of SH resulted in significant reductions in clinically important heart parameters such as LVMI, HR, and cardiac index. SH should be regarded as a condition in which aggressive treatment should be considered to protect cardiac function. PMID:25568332

  4. Evaluating High Order resonances using Resonant Normal Forms

    Microsoft Academic Search

    Ezio Todesco; F Schmidt

    1996-01-01

    Resonant normal forms allow to study various aspects of resonances up to high orders. We apply these techniques to evaluate resonances in four phase space variables. The input is truncated one-turn map derived from standard tracking codes. A code automatically finds fixed line locations in phase space resonances up to a desired order. The island widths and the island tunes

  5. Nondestructive testing of adhesive bonds by nuclear quadrupole resonance method

    NASA Technical Reports Server (NTRS)

    Hewitt, R. R.

    1971-01-01

    Inert, strain sensitive tracer, cuprous oxide, added to polymeric adhesive ensures sufficiently large signal to noise ratio in NQR system output. Method is successful, provided that RF-transparent structural materials are used between modified adhesive and probe of NQR spectrometer.

  6. HCN, A Triple-Resonance NMR Technique for Selective Observation of Histidine and Tryptophan Side Chains in 13C/ 15N-Labeled Proteins

    NASA Astrophysics Data System (ADS)

    Sudmeier, James L.; Ash, Elissa L.; Günther, Ulrich L.; Luo, Xuelian; Bullock, Peter A.; Bachovchin, William W.

    HCN, a new 3D NMR technique for stepwise coherence transfer from 1H to 13C to 15N and reverse through direct spin couplings 1JCHand 1JCN, is presented as a method for detection and assignment of histidine and tryptophan side-chain 1H, 13C, and 15N resonances in uniformly 13C/ 15N-labeled proteins. Product-operator calculations of cross-peak volumes vs adjustable delay ? 3were employed for determination of optimal ? 3. For the phosphatidylinositol 3-kinase (PI3K SH3 domain, MW = 9.6 kD) at pH 6, H(C)N, the 1H/ 15N projection, produced observable cross peaks within 20 min. and was completely selective for the single tryptophan and single histidine. The 3D HCN experiment yielded well-defined cross peaks in 20 h for the 13C/ 15N-labeled origin-specific DNA binding domain from simian virus 40 T-antigen (T-ag-OBD 131-259, MW = 15.4 kD) at pH 5.5. Resonances from all six histidines in T-ag-OBD were observed, and 11 of the 12 1H and 13C chemical shifts and 10 of the 12 15N chemical shifts were determined. The 13C dimension proved essential in assignment of the multiply overlapping 1H and 15N resonances. From the spectra recorded at a single pH, three of the imidazoles were essentially neutral and the other three were partially protonated (22-37%). HCN yielded strong cross peaks after 18 h on a 2.0 m Msample of phenylmethanesulfonyl fluoride (PMSF)-inhibited ?-lytic protease (MW = 19.8 kD) at pH 4.4. No spectra have been obtained, however, of native or boronic acid-inhibited ?-lytic protease after 18 h at various temperatures ranging from 5 to 55°C, probably due to efficient relaxation of active-site imidazole 1H and/or 15N nuclei.

  7. Calculation of the nuclear quadrupole resonance spectra of YBa/sub 2/Cu/sub 3/O/sub 7/minus/x/

    SciTech Connect

    Winter, N.W.; Violet, C.E.

    1989-06-01

    Nuclear quadrupole resonance (NQR) and nuclear magnetic resonance (NMR) studies on /sup 63,65/Cu have demonstrated the the resonance properties of these nuclei can give important information about the electronic structure of the high temperature superconductor YBa/sub 2/Cu/sub 3/O/sub 7/minus/x/ as well as the exchange coupling energy between the Cu(2) sites. Measurements for various oxygen stoichiometries have given insight into the effect of oxygen content on the valence state of the Cu. In the work reported here, the electric field gradient (EFG) tensors at the Cu(1) and Cu(2) sites in YBa/sub 2/Cu/sub 3/O/sub 7/minus/x/, have been determined from calculations on large clusters for x = 0 and 1. 13 refs., 2 tabs.

  8. Crossing of depolarization resonances at saturne (SACLAY)

    NASA Astrophysics Data System (ADS)

    Grorud, E.; Laclare, J.-L.; Leleux, G.; Nakach, A.; Ropert, A.

    1983-03-01

    This paper gives the results of the 1981-1982 campaign of polarization measurements at Saturne. Resonance crossing techniques are given for each type of resonance. The adiabatic crossing of a resonance (spin flip) is proved to be reliable.

  9. Why currently used diagnostic techniques for heart failure in rheumatoid arthritis are not enough: the challenge of cardiovascular magnetic resonance imaging.

    PubMed

    Mavrogeni, Sophie; Dimitroulas, Theodoros; Gabriel, Sherine; Sfikakis, Petros P; Pohost, Gerald M; Kitas, George D

    2014-01-01

    Rheumatoid arthritis (RA) is a multiorgan inflammatory disorder affecting approximately 1% of the population that leads to progressive joint destruction and disability. Patients with RA exhibit a high risk of cardiovascular disease, which results in premature morbidity and mortality and reduced life expectancy, when compared with the general population. Among various guises of myocardial involvement, heart failure (HF) has been recently recognized as an important contributory factor to the excess cardiovascular mortality associated with RA. HF in RA typically presents with occult clinical symptomatology and is mainly associated with structural and functional left ventricular abnormalities leading to diastolic dysfunction, while systolic myocardial performance remains well preserved. As isolated diastolic dysfunction is a predictor of high mortality, the evaluation of patients in early asymptomatic stages, when treatment targeting the heart is more likely to be effective, is of great importance. Although patient history and physical examination remain the cornerstones of HF evaluation, noninvasive imaging of cardiac chambers, coronary arteries, and great vessels may be necessary. Echocardiography, nuclear techniques, and invasive coronary angiography are already established in the routine assessment of HF; however, many aspects of HF pathophysiology in RA remain obscure, due to the limitations of currently used techniques. The capability of cardiovascular magnetic resonance (CMR) to capture early tissue changes allows timely detection of pathophysiologic phenomena of HF in RA, such as myocardial inflammation and myocardial perfusion defects, due to either macrovascular (coronary artery disease) or microvascular (vasculitis) disease. Therefore, CMR may be a useful tool for early, accurate diagnosis and research in patients with RA. PMID:25662926

  10. A novel and selective assay for the quantitative analysis of molybdenum(VI) at nanogram level by resonance light scattering quenching technique.

    PubMed

    Chen, Zhan Guang; Zhu, Li; Zhang, Tai Yu; Liu, Jin Bin; Han, Ya Li

    2008-07-01

    A novel method is designed for the direct determination of trace amounts of molybdenum(VI) in tap water, human hair, and Chinese herbal medicine by means of decreasing resonance light scattering (RLS) technique. The characteristics of RLS spectra, the effective factors, and optimum conditions of the reaction were studied. In the medium of hydrochloric acid (pH 2.38), Mo(VI), dibromohydroxyphenylfluorone (DBHPF), and Triton X-100 react to form a complex, resulting in significant decreasing RLS signals of DBHPF-Triton X-100. The decreasing RLS intensity at 583.0 nm is proportional to the concentration of Mo(VI) up to 8.0 ng mL(-1). The detection limit is 0.013 ng mL(-1). The method is simple, reproducible, with reaction rapidity and stability of complexes formed. Moreover, the high selectivity and sensitivity of this method permits its direct determination of molybdenum(VI) in tap water, human hair, and Chinese herbal medicine and the results are in agreement with those obtained by the inductively coupled plasma atomic emission spectrometry (ICP-AES) method. PMID:17869168

  11. Artificial neural network assisted kinetic spectrophotometric technique for simultaneous determination of paracetamol and p-aminophenol in pharmaceutical samples using localized surface plasmon resonance band of silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Khodaveisi, Javad; Dadfarnia, Shayessteh; Haji Shabani, Ali Mohammad; Rohani Moghadam, Masoud; Hormozi-Nezhad, Mohammad Reza

    2015-03-01

    Spectrophotometric analysis method based on the combination of the principal component analysis (PCA) with the feed-forward neural network (FFNN) and the radial basis function network (RBFN) was proposed for the simultaneous determination of paracetamol (PAC) and p-aminophenol (PAP). This technique relies on the difference between the kinetic rates of the reactions between analytes and silver nitrate as the oxidizing agent in the presence of polyvinylpyrrolidone (PVP) which is the stabilizer. The reactions are monitored at the analytical wavelength of 420 nm of the localized surface plasmon resonance (LSPR) band of the formed silver nanoparticles (Ag-NPs). Under the optimized conditions, the linear calibration graphs were obtained in the concentration range of 0.122-2.425 ?g mL-1 for PAC and 0.021-5.245 ?g mL-1 for PAP. The limit of detection in terms of standard approach (LODSA) and upper limit approach (LODULA) were calculated to be 0.027 and 0.032 ?g mL-1 for PAC and 0.006 and 0.009 ?g mL-1 for PAP. The important parameters were optimized for the artificial neural network (ANN) models. Statistical parameters indicated that the ability of the both methods is comparable. The proposed method was successfully applied to the simultaneous determination of PAC and PAP in pharmaceutical preparations.

  12. Stochastic Resonance

    NASA Astrophysics Data System (ADS)

    McDonnell, Mark D.; Stocks, Nigel G.; Pearce, Charles E. M.; Abbott, Derek

    2012-10-01

    Preface; 1. Introduction and motivation; 2. Stochastic resonance: its definitions, history and debates; 3. Stochastic quantization; 4. Suprathreshold stochastic resonance: encoding; 5. Suprathreshold stochastic resonance: large N encoding; 6. Suprathreshold stochastic resonance: decoding; 7. Suprathreshold stochastic resonance: large N decoding; 8. Optimal stochastic quantization; 9. SSR, neural coding, and performance tradeoffs; 10. Stochastic resonance in the auditory system; 11. The future of stochastic resonance and suprathreshold stochastic resonance; Appendices; References; Index.

  13. Immediate effect of mind sound resonance technique on state anxiety and cognitive functions in patients suffering from generalized anxiety disorder: A self-controlled pilot study

    PubMed Central

    Dhansoia, Vipin; Bhargav, Hemant; Metri, Kashinath

    2015-01-01

    Objectives: To compare the immediate effect of mind sound resonance technique (MSRT) with supine rest (SR) on state anxiety and psychomotor performance in 15 (eight male and seven female) right-handed generalized anxiety disorder patients (GAD) with an age range of 34.8 ± 12.8 years. Materials and Methods: Self as control design was followed. Diagnosis of GAD was made by a psychiatrist using sections of the Mini International Neuropsychiatric Interview (MINI). Participants practiced MSRT or SR (as control intervention) for 30 min at the same time for two consecutive days. The sequence of intervention was assigned randomly to the participants. State anxiety was assessed using state trait anxiety inventory (STAI; Form X1). Digit letter substitution task (DLST) was used to assess psychomotor performance, which involves visual scanning, mental flexibility, sustained attention, psychomotor speed and speed of information processing. Intervention was given in a quiet dark room on an empty stomach. Subjects received a training of MSRT and SR for 1 week before the data were taken. A pre-recorded audiotape was used to administer the technique of MSRT. Difference in scores after baseline and intervention was used to check normality, and was found to be normally distributed by the Kolmogrov–Smirnov test. The changes in STAI, DLST and difference in scores before and after two interventions (MSRT and SR) were compared using the paired samples t test. Results: As compared with baseline, STAI scores reduced and DLST scores increased significantly (STAI; P < 0.01; DLST; P < 0.01) after MSRT. After SR, there was a significant reduction in STAI scores from baseline (STAI; P < 0.05), but there was no significant change in the DLST scores (P = 0.26). Comparison of the difference in scores for DLST and STAI before and after the two interventions (MSRT and SR) showed a significantly higher score for DLST (P < 0.05) and a significantly lower score for STAI (P < 0.01) for MSRT as compared with SR. Conclusion: This pilot study suggests that MSRT may have a potential role in reducing state anxiety and enhancing psychomotor performance in patients suffering from GAD immediately after the practice. These findings need confirmation from studies with a larger sample size and randomized controlled design, which are implicated in the future. PMID:25558137

  14. Resonant Doppler velocimeter

    NASA Technical Reports Server (NTRS)

    Miles, R. B.

    1975-01-01

    Narrow linewidth tunable lasers augur a new kind of laser Doppler velocimetry employing resonant absorption and fluorescence from trace atomic species rather than scattering from particles. This technique may provide better turbulence and small volume information than present velocimetry.

  15. Effect of a weak static magnetic field on nitrogen-14 quadrupole resonance in the case of an axially symmetric electric field gradient tensor.

    PubMed

    Guendouz, Laoučs; Aissani, Sarra; Maręché, Jean-François; Retournard, Alain; Marande, Pierre-Louis; Canet, Daniel

    2013-01-01

    The application of a weak static B0 magnetic field (less than 1 mT) may produce a well-defined splitting of the (14)N Quadrupole Resonance line when the electric field gradient tensor at the nitrogen nucleus level is of axial symmetry. It is theoretically shown and experimentally confirmed that the actual splitting (when it exists) as well as the line-shape and the signal intensity depends on three factors: (i) the amplitude of B0, (ii) the amplitude and pulse duration of the radio-frequency field, B1, used for detecting the NQR signal, and (iii) the relative orientation of B0 and B1. For instance, when B0 is parallel to B1 and regardless of the B0 value, the signal intensity is three times larger than when B0 is perpendicular to B1. This point is of some importance in practice since NQR measurements are almost always performed in the earth field. Moreover, in the course of this study, it has been recognized that important pieces of information regarding line-shape are contained in data points at the beginning of the free induction decay (fid) which, in practice, are eliminated for avoiding spurious signals due to probe ringing. It has been found that these data points can generally be retrieved by linear prediction (LP) procedures. As a further LP benefit, the signal intensity loss (by about a factor of three) is regained. PMID:24183810

  16. High frequency STW resonator filters

    Microsoft Academic Search

    R. Almar; B. Horine; J. Andersen

    1992-01-01

    The authors present results obtained in the 1-GHz-2-GHz region for surface transverse wave (STW) resonator filters implemented using inline coupled (RFI) and combined mode resonator filter (CMRF) techniques. The STW device performance is strongly dependent on the surface confinement of the acoustic wave. In an inline resonator filter the inner grating serves the dual purpose of trapping the energy near

  17. A Micromachined Tunable Cavity Resonator

    Microsoft Academic Search

    D. Mercier; M. Chatras; J. C. Orlianges; C. Champeaux; A. Catherinot; P. Blondy; D. Cros; J. Papapolymerou

    2003-01-01

    This paper focuses on a tunable resonator fabricated using bulk and surface micro-machining techniques. The resonator consists of a silicon micro-machined metalized cavity coupled with a MEMS bridge capacitor for tunability purposes. The resonator is excited using coplanar waveguide lines to avoid losses from transitions and facilitate measurements. The unloaded quality factor of the device is about 150 depending on

  18. 73Ge-Nuclear Magnetic Resonance/Nuclear Quadrupole Resonance Investigation of Magnetic Properties of URhGe

    NASA Astrophysics Data System (ADS)

    Kotegawa, Hisashi; Fukumoto, Kenta; Toyama, Toshihiro; Tou, Hideki; Harima, Hisatomo; Harada, Atsushi; Kitaoka, Yoshio; Haga, Yoshinori; Yamamoto, Etsuji; ?nuki, Yoshichika; Itoh, Kohei M.; Haller, Eugene E.

    2015-05-01

    We report on the 73Ge-nuclear magnetic resonance (NMR)/nuclear quadrupole resonance (NQR) results for the ferromagnetic (FM) superconductor URhGe. The magnitude and direction of the internal field, Hint, and the parameters of the electric field gradient at the Ge site were determined experimentally. By using powdered polycrystalline samples oriented by different methods, the field dependences of NMR shift and nuclear spin relaxation rates for H0 || c (easy axis) and H0 || b were obtained. From the NMR shifts for H0 || b, we confirmed a gradual suppression of the Curie temperature and observed a phase separation near the spin reorientation. The observation of the phase separation gives microscopic evidence that the spin reorientation under H0 || b is of first order at low temperatures. The nuclear spin-lattice relaxation rate 1/T1 indicates that the magnetic fluctuations are suppressed for H0 || c, whereas the fluctuations remain strongly for H0 || b. The enhancements of both 1/T1T and the nuclear spin-spin relaxation rate 1/T2 for H0 || b toward the spin reorientation field suggest that the field-induced superconductivity in URhGe emerges under the magnetic fluctuations along the b- and c-axes.

  19. Novel multisample dielectric resonators for electron paramagnetic resonance spectroscopy

    NASA Astrophysics Data System (ADS)

    Golovina, Iryna S.; Kolesnik, Sergiy P.; Geifman, Ilia N.; Belous, Anatoliy G.

    2010-04-01

    We have developed and tested two types of novel dielectric resonators for simultaneous recording of electron paramagnetic resonance (EPR) spectra from two to four samples. The resonator of the first type contains two holes, and the other resonator contains four holes for introduction of the samples. Also, the resonator structure includes a pair of gradient coils. Dielectric resonators made of materials with high dielectric constant with low losses can be inserted into the standard EPR cavity or waveguide in the maximum microwave magnetic field. Gradient coils are located outside the cavity (or waveguide) so that their axes are parallel to the static magnetic field. Computer simulations were made to obtain microwave characteristics of the resonators such as resonant frequency, sizes, and distribution of the fields. Spacing of the point samples and optimum value of the magnetic-field gradient have been chosen correctly. The designed resonators can be applied in express analysis using EPR technique, for instance.

  20. Electrostatic (plasmon) resonances in nanoparticles

    NASA Astrophysics Data System (ADS)

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

    2005-10-01

    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.

  1. Subfemtotesla radio-frequency atomic magnetometer for detection of nuclear quadrupole resonance

    E-print Network

    Romalis, Mike

    Hz 14 N NQR frequency of ammonium nitrate. A potential application of the magnetometer is detection-to-noise ratio SNR below a few megahertz. The NQR signal from 22 g of powdered ammonium nitrate located 2 cm away from the sensor is detected with a SNR of 9 in a 4.4-s-long multiple echo sequence, which represents

  2. Resonance Ionization, Mass Spectrometry.

    ERIC Educational Resources Information Center

    Young, J. P.; And Others

    1989-01-01

    Discussed is an analytical technique that uses photons from lasers to resonantly excite an electron from some initial state of a gaseous atom through various excited states of the atom or molecule. Described are the apparatus, some analytical applications, and the precision and accuracy of the technique. Lists 26 references. (CW)

  3. NMR-NQR study of the crossover from the spin-glass to the superconducting phase in La{sub 2{minus}x}Sr{sub x}CuO{sub 4}

    SciTech Connect

    Julien, M.H.; Carretta, P.; Borsa, F.; Rigamonti, A. [Unita INFM di Pavia (Italy). Dipt. di Fisica] [Unita INFM di Pavia (Italy). Dipt. di Fisica

    1999-04-20

    {sup 139}La and {sup 63}Cu NQR relaxation rates are used to obtain insights on the effects of itinerant holes on the magnetic in-plane correlation length, for x {le} 0.04 in La{sub 2{minus}x}Sr{sub x}CuO{sub 4}. For these concentrations, corresponding to spin-glass behavior at low temperature, evidence for the microsegregation of holes along stripes is presented. Preliminary relaxation results for an amount of Sr doping leading to superconductivity are also presented and discussed in terms of the crossover from the spin-glass to the underdoped superconducting regime: for x = 0.06 a slowing down of spin fluctuations is evidenced and superconductivity is found to coexist with spin-freezing.

  4. Spin dynamics in a two-dimensional disordered S=(1)/(2) Heisenberg paramagnet from {sup 63}Cu NQR relaxation in Zn-doped La{sub 2}CuO{sub 4}

    SciTech Connect

    Carretta, P.; Rigamonti, A.; Sala, R. [Department of Physics A. Volta, Unita INFM and Sezione INFN di Pavia, Via Bassi, 6, 27100-I Pavia (Italy)] [Department of Physics A. Volta, Unita INFM and Sezione INFN di Pavia, Via Bassi, 6, 27100-I Pavia (Italy)

    1997-02-01

    {sup 63}Cu NQR T{sub 1} and T{sub 2} relaxation measurements in La{sub 2}Cu{sub 1{minus}x}Zn{sub x}O{sub 4}, for 0{le}x{le}0.11 and in the temperature range T{sub N}{le}T{le}900 K, are presented. The results are used to derive insights into the Cu{sup 2+} correlated spin dynamics in the paramagnetic phase of the S=(1)/(2) two-dimensional (2D) Heisenberg (H) antiferromagnets (AF), and into the disorder effects associated with the spin vacancy due to Zn{sup 2+} (S=0) for Cu{sup 2+} substitution. In particular, by using scaling arguments for the static generalized susceptibility, {chi}({rvec q},0), and for the decay rate, {Gamma}{sub {rvec q}}, of the normal excitations, T{sub 2} and T{sub 1} are related to the in-plane correlation length {xi}{sub 2D}(x,T) and its dependence on temperature and Zn doping, x, is extracted. The experimental findings are analyzed in light of the quantum critical and renormalized classical behaviors for {xi}{sub 2D} predicted by recent theories for S=1/2 HAF on square lattices. It is shown that up to T{approx_equal}900 K, {xi}{sub 2D} is consistent with the assumption of a renormalized classical regime, in agreement with recent neutron scattering results and at variance with previous interpretations of the NQR data. It is discussed how Zn affects {xi}{sub 2D} through the modification in the spin stiffness and comparison with the disorder induced by itinerant extra holes is made.

  5. Technical failure to perform cardiac resynchronization therapy: Use of cardiac magnetic resonance imaging techniques to clarify a left-sided superior vena cava and coronary sinus morphology

    PubMed Central

    Keeble, William; Mohiaddin, Raad

    2008-01-01

    The most common reason for failure to implant a left ventricular lead to deliver cardiac resynchronization therapy is the presence of unfavourable coronary venous anatomy. The present report illustrates the use of cardiac magnetic resonance imaging to delineate the anatomy of a left-sided superior vena cava in two patients in whom permanent cardiac pacing was unattainable. PMID:18612503

  6. Study on the interaction between nucleic acid and Eu 3+–oxolinic acid and the determination of nucleic acid using the resonance light scattering technique

    Microsoft Academic Search

    Xia Wu; Shuna Sun; Jinghe Yang; Minqin Wang; Liyan Liu; Changying Guo

    At pH 9.75, the resonance light scattering (RLS) intensity of OA–Eu3+ system is greatly enhanced by nucleic acid. Based on this phenomenon, a new quantitative method for nucleic acid in aqueous solution has been developed. Under the optimum condition, the enhanced RLS is proportional to the concentration of nucleic acid in the range of 1.0×10?9 to 1.0×10?6g\\/ml for herring sperm

  7. Study on the interaction between nucleic acid and Eu 3+–oxolinic acid and the determination of nucleic acid using the resonance light scattering technique

    Microsoft Academic Search

    Xia Wu; Shuna Sun; Jinghe Yang; Minqin Wang; Liyan Liu; Changying Guo

    2005-01-01

    At pH 9.75, the resonance light scattering (RLS) intensity of OA–Eu3+ system is greatly enhanced by nucleic acid. Based on this phenomenon, a new quantitative method for nucleic acid in aqueous solution has been developed. Under the optimum condition, the enhanced RLS is proportional to the concentration of nucleic acid in the range of 1.0×10?9 to 1.0×10?6g\\/ml for herring sperm

  8. Magnetic resonance coronary angiography with vasovist™: in-vivo T 1 estimation to improve image quality of navigator and breath-hold techniques

    Microsoft Academic Search

    Kai Nassenstein; Kai-Uwe Waltering; Sebastian Kelle; Thomas Schlosser; Frank Breuckmann; Stefan Maderwald; Peter Hunold; Eike Nagel; Jörg Barkhausen

    2008-01-01

    The purpose of the study was to estimate T\\u000a 1 values of blood and myocardium after a single injection of Vasovist™ and to assess Vasovist™ for magnetic resonance coronary\\u000a angiography (MRCA). For all exams 0.05 mmol\\/kg of Vasovist™ was injected. T\\u000a 1 values of blood and myocardium were estimated over 30 min after injection. Twelve volunteers were examined on a 1.5-T Siemens

  9. Self-diffusion of water-ethanol mixture in chitosan membranes obtained by pulsed-field gradient nuclear magnetic resonance technique

    Microsoft Academic Search

    Vitalij I. Volkov; Vladimr D. Skirda; Elena N. Vasina; Svetlana A. Korotchkova; H. Ohya; K. Soontarapa

    1998-01-01

    The self-diffusion of water and ethanol for crosslinked and uncrosslinked chitosan membranes have been investigated by pulsed-field gradient nuclear magnetic resonance (NMR) spectroscopy. It has been shown that during diffusion processes, water and ethanol are localized in different parts of the chitosan membrane. In the crosslinked membrane, the self-diffusion coefficient for water is higher, but that for ethanol is essentially

  10. Advanced soft-switching sinewave PWM high-frequency inverter-link cycloconverter incorporating voltage-clamped quasi-resonant and capacitive snubber techniques

    Microsoft Academic Search

    H. Yoneniori; M. Nakaoka

    1991-01-01

    An improved version of a sinewave CVCF power conversion conditioning system (PCS) which is based on a high-frequency (HF) transformer isolated-linked cycloconversion circuit incorporating soft-switching phase shifted PWM (PSM) principle and instantaneous voltage regulation strategy is discussed. This circuit topology and the modifications of the voltage-clamped quasi-resonant pole (QR-P) concept, which comprises inverter-cycloconverter cascaded power conversion stages operating under the

  11. New soft-switching phase-shifted PWM high-frequency inverter-linked cycloconverter incorporating voltage-clamped quasi-resonant technique

    Microsoft Academic Search

    H. Yonemori; A. Chibani; M. Nakaoka

    1991-01-01

    A sinewave CVCF power conversion conditioning system (PCS) based on a high-frequency (HF)-isolated AC-link cycloconversion circuit using soft-switching phase-shifted PWM (PSM) and instantaneous voltage regulation schemes is presented. This advanced circuit topology of voltage-clamped quasi-resonant (QR) switch concept, which comprises two-cascaded power conversion stages operating under the principle of zero-voltage switching (ZVS), is introduced in order to minimize switching losses,

  12. Injection-controlled laser resonator

    DOEpatents

    Chang, Jim J. (Dublin, CA)

    1995-07-18

    A new injection-controlled laser resonator incorporates self-filtering and self-imaging characteristics with an efficient injection scheme. A low-divergence laser signal is injected into the resonator, which enables the injection signal to be converted to the desired resonator modes before the main laser pulse starts. This injection technique and resonator design enable the laser cavity to improve the quality of the injection signal through self-filtering before the main laser pulse starts. The self-imaging property of the present resonator reduces the cavity induced diffraction effects and, in turn, improves the laser beam quality.

  13. Injection-controlled laser resonator

    DOEpatents

    Chang, J.J.

    1995-07-18

    A new injection-controlled laser resonator incorporates self-filtering and self-imaging characteristics with an efficient injection scheme. A low-divergence laser signal is injected into the resonator, which enables the injection signal to be converted to the desired resonator modes before the main laser pulse starts. This injection technique and resonator design enable the laser cavity to improve the quality of the injection signal through self-filtering before the main laser pulse starts. The self-imaging property of the present resonator reduces the cavity induced diffraction effects and, in turn, improves the laser beam quality. 5 figs.

  14. NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts. Quarterly technical progress report, June 15--September 15, 1991

    SciTech Connect

    Not Available

    1991-12-17

    The primary objective of the project is to examine the relations between the catalytic and magnetic properties of the copper-cobalt higher alcohol synthesis catalysts. We have undertaken to investigate the magnetic character by studying the Nuclear Quadrupole resonance of copper and (Zerofield) Nuclear Magnetic Resonance of cobalt in copper cobalt catalysts.

  15. NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts. Quarterly technical progress report, March 15--June 15, 1991

    SciTech Connect

    Not Available

    1991-07-15

    The primary objective of the project is to examine the relations between the catalytic and magnetic properties of the copper-cobalt higher alcohol synthesis catalysts. We have undertaken to investigate the magnetic character by studying the Nuclear Quadrupole resonance of copper and (Zerofield) Nuclear Magnetic Resonance of cobalt in copper cobalt catalysts.

  16. Zero field NMR and NQR

    SciTech Connect

    Zax, D.B.; Bielecki, A.; Zilm, K.W.; Pines, A.; Weitekamp, D.P.

    1985-11-15

    Methods are described and demonstrated for detecting the coherent evolution of nuclear spin observables in zero magnetic field with the full sensitivity of high field NMR. The principle motivation is to provide a means of obtaining solid state spectra of the magnetic dipole and electric quadrupole interactions of disordered systems without the line broadening associated with random orientation with respect to the applied magnetic field. Comparison is made to previous frequency domain and high field methods. A general density operator formalism is given for the experiments where the evolution period is initiated by a sudden switching to zero field and is terminated by a sudden restoration of the field. Analytical expressions for the signals are given for a variety of simple dipolar and quadrupolar systems and numerical simulations are reported for up to six coupled spin-1/2 nuclei. Experimental results are reported or reviewed for /sup 1/H, /sup 2/D, /sup 7/Li, /sup 13/C, and /sup 27/Al nuclei in a variety of polycrystalline materials. The effects of molecular motion and bodily sample rotation are described. Various extensions of the method are discussed, including demagnetized initial conditions and correlation by two-dimensional Fourier transformation of zero field spectra with themselves or with high field spectra.

  17. X-ray resonant single-crystal diffraction technique, a powerful tool to investigate the kesterite structure of the photovoltaic Cu2ZnSnS4 compound.

    PubMed

    Lafond, Alain; Choubrac, Léo; Guillot-Deudon, Catherine; Fertey, Pierre; Evain, Michel; Jobic, Stéphane

    2014-04-01

    Cu/Zn disorder in the kesterite Cu2ZnSnS4 derivatives used for thin film based solar cells is an important issue for photovoltaic performances. Unfortunately, Cu and Zn cannot be distinguished by conventional laboratory X-ray diffraction. This paper reports on a resonant diffraction investigation of a Cu2ZnSnS4 single crystal from a quenched powdered sample. The full disorder of Cu and Zn in the z = 1/4 atomic plane is shown. The structure, namely disordered kesterite, is then described in the I42m space group. PMID:24675608

  18. Quantitative determination of proteins at nanogram levels by the resonance light-scattering technique with composite nanoparticles of CdS/PAA

    NASA Astrophysics Data System (ADS)

    Chen, Hongqi; Xu, Fagong; Hong, Shi; Wang, Lun

    2006-10-01

    This paper describes the development of composite nanoparticles. A novel composite nanoparticle has been prepared by an in situ polymerization method. The nano-CdS has been prepared, then the polymerization of acrylic acid (AA) was carried out by initiator potassium persulfate (KPS) under ultrasonic irradiation. The surface of the composite nanoparticles was covered with abundant carboxylic groups (-COOH). The nanoparticles are water-soluble, stable and biocompatible. Reaction of the composite nanoparticles with proteins results in an enhanced resonance light scattering (RLS) at 380 nm. Based on this, a new resonance light-scattering (RLS) method was developed for the determination of proteins including BSA, HSA and human ?-IgG. Under the optimum conditions, the enhanced RLS intensity is linearly proportional to the concentration of proteins. The liner range is 0.1-15 ?g mL -1 for HSA, 0.2-20 ?g mL -1 for BSA and 0.1-50.0 ?g mL -1 for human ?-IgG, respectively. The method has been applied to the determination of the total protein in human serum samples collected from the hospital and the results are in good agreement with those reported by the hospital. This method proved to be very sensitive, rapid, simple and tolerant of most interfering substances.

  19. Low-temperature order in the heavy-fermion compound CeCu{sub 6}

    SciTech Connect

    Pollack, L.; Hoch, M.J.R.; Jin, C.; Smith, E.N.; Parpia, J.M.; Hawthorne, D.L.; Geller, D.A.; Lee, D.M.; Richardson, R.C. [Cornell Microkelvin Laboratory, Materials Science Center, Cornell University, Ithaca, New York 14853 (United States); Hinks, D.G. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Bucher, E. [AT& T Bell Laboratories, Murray Hill, New Jersey 07974 (United States)

    1995-12-01

    We have used nuclear-quadrupole-resonance (NQR) techniques to study Cu nuclei in two single-crystal samples of CeCu{sub 6} between 200 {mu}K and 20 mK. We present measurements of the NQR intensities and spin-lattice relaxation times, {ital T}{sub 1}, at frequencies corresponding to three different sites in the crystal. Below 5 mK we observe deviations from standard metallic behavior in both signal intensity and spin-lattice relaxation times. These deviations are unusual in that they are site dependent; they reveal the presence of one or more types of order in this system.

  20. Magnetic resonance imaging methodology

    Microsoft Academic Search

    Ewald Moser; Andreas Stadlbauer; Christian Windischberger; Harald H. Quick; Mark E. Ladd

    2009-01-01

    Introduction  Magnetic resonance (MR) methods are non-invasive techniques to provide detailed, multi-parametric information on human anatomy,\\u000a function and metabolism. Sensitivity, specificity, spatial and temporal resolution may, however, vary depending on hardware\\u000a (e.g., field strength, gradient strength and speed) and software (optimised measurement protocols and parameters for the various\\u000a techniques). Furthermore, multi-modality imaging may enhance specificity to better characterise complex disease patterns.

  1. Magnetic resonance urography

    Microsoft Academic Search

    John R. Leyendecker; John W. Gianini

    2009-01-01

    Excellent contrast resolution and lack of ionizing radiation make magnetic resonance urography (MRU) a promising technique\\u000a for noninvasively evaluating the entire urinary tract. While MRU currently lags behind CT urography (CTU) in spatial resolution\\u000a and efficiency, new hardware and sequence developments have contributed to a resurgence of interest in MRU techniques. By\\u000a combining unenhanced sequences with multiphase contrast-enhanced and excretory

  2. Morphological resonances for multicomponent immunoassays

    NASA Astrophysics Data System (ADS)

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

    1995-06-01

    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.

  3. SPECTRAL IMAGING TECHNIQUES FOR GRAIN

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three spectral imaging techniques were employed for the purpose of assessing the quality of cereal grains. Each of these techniques provided unique, yet complementary, information. Nuclear magnetic resonance (NMR), also called magnetic resonance imaging (MRI), was used to detect mobile components ...

  4. [A new concept in imaging pelvic recurrence of curatively operated rectal carcinoma--image fusion of nuclear magnetic resonance tomography and anti-CEA immunoscintigraphy (SPECT): technique and clinical example].

    PubMed

    Kronberger, L; Fueger, G F; Nicoletti, R; Ranner, G; Wiltgen, M; Stollberger, R; Graif, E; Uranüs, S; Hauser, H; Mischinger, H J

    1995-01-01

    We present a new technique of image fusion (IF) of magnetic resonance imaging (MRT) and anti-CEA-immunoscintigraphy (Behring 431/26) and single photon emission computed tomography (SPECT). We performed SPECT and MRT within 8 hours on the same day. Glucagon intravenously was used to reduce artefacts due to intestinal motility. Before image fusion we analysed the SPECT and MRT images independently of each other. The MRT and SPECT were connected by a local area network (LAN) to a Gateway computer, which is also used as a picture archive. There a program automatically starts, translates the MRT data from the ACR/NEMA format to the Elscint one and these data are sent for image fusion to the nuclear medicine computer Elscint SP1. By means of a clinical example we present anatomic concordant superimposition and explain the findings and the clinical value of our technique. This system and technique are equally applicable to other digital imaging investigations. By IF, on the basis of the certain evidence of the tracer depot of a pathological lesion diagnosed by MRT and the reliability of the anatomical assignment of a focal lesion diagnosed by SPECT, early detection of local recurrence after surgical treatment of rectal cancer, the correct localisation of recurrent disease and its distinction from non-malignant tissue becomes possible. This enables planning of further therapeutical strategies. PMID:8560891

  5. Coronary magnetic resonance angiography

    Microsoft Academic Search

    Matthias Stuber; Robert G. Weiss

    2007-01-01

    Coronary magnetic resonance angiography (MRA) is a pow- erful noninvasive technique with high soft-tissue contrast for the visualization of the coronary anatomy without X-ray exposure. Due to the small dimensions and tortuous na- ture of the coronary arteries, a high spatial resolution and sufficient volumetric coverage have to be obtained. How- ever, this necessitates scanning times that are typically much

  6. Optimizing C{sup 4+} and C{sup 5+} beams of the Kei2 electron cyclotron resonance ion source using a special gas-mixing technique

    SciTech Connect

    Drentje, A.G.; Muramatsu, M.; Kitagawa, A. [K.V.I., University of Groningen, Zernikelaan 25, 9747AA Groningen (Netherlands); National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage, Chiba 263-8555 (Japan)

    2006-03-15

    With the prototype electron cyclotron resonance ion source for the next carbon therapy facility in Japan a series of measurements has been performed in order (a) to find the best condition for producing high beam currents of C{sup 4+} ions, and (b) to study the effect of 'special' gas mixing by using a chemical compound as a feed gas. The effect would then appear as an increase in high charge state production in this case of C{sup 5+} ions. In 'regular' gas-mixing experiments it is well known that an isotopic phenomenon occurs: a heavier isotope of the mixing gas is increasing the production of high charge states of the beam gas ions. A similar isotopic effect has been found in the present experiment: with deuterated methane (CD{sub 4} gas) the C{sup 5+} beam currents are about 10% higher than with regular methane (CH{sub 4} gas). The 'mixing-gas' ratio D (or H) to C can be decreased by choosing, e.g., butane gas; in this case the isotopic effect for C{sup 5+} production is even stronger (>15%). For production of C{sup 4+} ions the isotopic effect appears to be absent. Clearly this is related to the much easier production. It turns out that the relative amount of carbon is much more important: butane gives about 10% higher C{sup 4+}-ion currents than methane.

  7. Quality factor control for micromechanical resonators

    Microsoft Academic Search

    C. T.-C. Nguyen; R. T. Howe

    1992-01-01

    The implementation of very high Q microelectromechanical filters, constructed of spring-coupled or parallel resonators, requires strict control over the quality factor of the constituent resonators. This report details electrostatic feedback techniques which allow precise control of the quality factor of a micromechanical resonator device, independent of the ambient operating pressure of the micromechanical system. Theoretical formulas governing Q-control are derived

  8. Optical resonator

    NASA Technical Reports Server (NTRS)

    Taghavi-Larigani, Shervin (Inventor); Vanzyl, Jakob J. (Inventor); Yariv, Amnon (Inventor)

    2006-01-01

    The invention discloses a semi-ring Fabry-Perot (SRFP) optical resonator structure comprising a medium including an edge forming a reflective facet and a waveguide within the medium, the waveguide having opposing ends formed by the reflective facet. The performance of the SRFP resonator can be further enhanced by including a Mach-Zehnder interferometer in the waveguide on one side of the gain medium. The optical resonator can be employed in a variety of optical devices. Laser structures using at least one SRFP resonator are disclosed where the resonators are disposed on opposite sides of a gain medium. Other laser structures employing one or more resonators on one side of a gain region are also disclosed.

  9. Phosphonated trityl probes for concurrent in vivo tissue oxygen and pH monitoring using electron paramagnetic resonance-based techniques.

    PubMed

    Dhimitruka, Ilirian; Bobko, Andrey A; Eubank, Timothy D; Komarov, Denis A; Khramtsov, Valery V

    2013-04-17

    Previously we proposed the concept of dual function pH and oxygen paramagnetic probes based on the incorporation of ionizable groups into the structure of persistent triarylmethyl radicals, TAMs (J. Am. Chem. Soc.2007, 129, 7240-7241). In this paper, we synthesized an asymmetric monophosphonated TAM probe with the simplest doublet hfs pattern ideally suited for dual function electron paramagnetic resonance (EPR)-based applications. An extraordinary low line width of the synthesized deuterated derivative, p1TAM-D (?Hpp ? 50 mG, Lorentz line width, ?20 mG) results in high sensitivity to pO2 due to oxygen-induced line broadening (?LW/?pO2 ? 0.5 mG/mmHg or ?400 mG/mM); accuracy of pO2 measurement, ?1 mmHg). The presence of a phosphono group in the p1TAM-D structure provides pH sensitivity to its EPR spectra in the physiological range of pH from 5.9 to 8.2 with the ratio of signal intensities of protonated and deprotonated states being a reliable pH marker (accuracy of pH measurements, ± 0.05). The independent character of pH and [O2] effects on the EPR spectra of p1TAM-D provides dual functionality to this probe. The L-band EPR studies performed in breast tumor-bearing mice show a significant difference in extracellular pH and pO2 between tumor and normal mammary gland tissues, as well as the effect of animal breathing with 100% O2 on tissue oxygenation. The developed dual function phosphonated p1TAM-D probe provides a unique tool for in vivo concurrent tissue oxygen and pH monitoring. PMID:23517077

  10. Superconducting fluctuations and {sup 63}Cu NQR-NMR relaxation in YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}: Effect of magnetic field and a test for the pairing-state symmetry

    SciTech Connect

    Carretta, P. [Department of Physics ``A. Volta,`` Sezione di Pavia, Istituto Nazionale di Fisica Nucleare and Unita Instituto Nazionale di Fisica della Materia, University of Pavia, Via Bassi 6, I-27100, Pavia (Italy)] [Department of Physics ``A. Volta,`` Sezione di Pavia, Istituto Nazionale di Fisica Nucleare and Unita Instituto Nazionale di Fisica della Materia, University of Pavia, Via Bassi 6, I-27100, Pavia (Italy); Livanov, D.V. [Department of Theoretical Physics, Moscow Institute of Steel and Alloys, 117936 Moscow (Russia)] [Department of Theoretical Physics, Moscow Institute of Steel and Alloys, 117936 Moscow (Russia); Rigamonti, A. [Department of Physics ``A. Volta,`` Sezione di Pavia, Istituto Nazionale di Fisica Nucleare and Unita Instituto Nazionale di Fisica della Materia, University of Pavia, Via Bassi 6, I-27100, Pavia (Italy)] [Department of Physics ``A. Volta,`` Sezione di Pavia, Istituto Nazionale di Fisica Nucleare and Unita Instituto Nazionale di Fisica della Materia, University of Pavia, Via Bassi 6, I-27100, Pavia (Italy); Varlamov, A.A. [Department of Theoretical Physics, Moscow Institute of Steel and Alloys, 117936 Moscow (Russia)] [Department of Theoretical Physics, Moscow Institute of Steel and Alloys, 117936 Moscow (Russia); [Laboratorium ``Forum,`` Instituto Nazionale di Fisica della Materia, Department of Physics, University of Florence, Florence (Italy)

    1996-10-01

    Evidence is presented of superconducting fluctuations in the {sup 63}Cu NQR-NMR relaxation rate in YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}, as obtained from a careful comparison of measurements carried out in the absence and in the presence of a field parallel to the {ital c} axis. It is shown that the field causes a reduction of the relaxation rate {ital W} in a range of about 10 K above {ital T}{sub {ital c}}. This effect is related to the suppression by the magnetic field of the phase-sensitive positive Maki-Thompson contribution while the negative contribution from the DOS fluctuations is almost field independent. Furthermore, it is argued how the fluctuation effects on {ital W} can be used to discuss the pairing state symmetry, at variance with the insensitivity of the transport measurements. It is pointed out that the existence of the Maki-Thompson contribution to {ital W} evidences an {ital s}-wave symmetry component for the pairing in YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}. {copyright} {ital 1996 The American Physical Society.}

  11. Two-frequency heating technique at the 18 GHz electron cyclotron resonance ion source of the National Institute of Radiological Sciences

    NASA Astrophysics Data System (ADS)

    Biri, S.; Kitagawa, A.; Muramatsu, M.; Drentje, A. G.; Rácz, R.; Yano, K.; Kato, Y.; Sasaki, N.; Takasugi, W.

    2014-02-01

    The two-frequency heating technique was studied to increase the beam intensities of highly charged ions provided by the high-voltage extraction configuration (HEC) ion source at the National Institute of Radiological Sciences (NIRS). The observed dependences on microwave power and frequency suggested that this technique improved plasma stability but it required precise frequency tuning and more microwave power than was available before 2013. Recently, a new, high-power (1200 W) wide band-width (17.1-18.5 GHz) travelling-wave-tube amplifier (TWTA) was installed. After some single tests with klystron and TWT amplifiers the simultaneous injection of the two microwaves has been successfully realized. The dependence of highly charged ions (HCI) currents on the superposed microwave power was studied by changing only the output power of one of the two amplifiers, alternatively. While operating the klystron on its fixed 18.0 GHz, the frequency of the TWTA was swept within its full limits (17.1-18.5 GHz), and the effect of this frequency on the HCI-production rate was examined under several operation conditions. As an overall result, new beam records of highly charged argon, krypton, and xenon beams were obtained at the NIRS-HEC ion source by this high-power two-frequency operation mode.

  12. Direct measurement of water self-diffusion in hardening blast furnace slag cement pastes by means of nuclear magnetic resonance techniques

    SciTech Connect

    Nestle, N.; Galvosas, P.; Karger, J.

    2001-07-01

    Recently, we have reported the unusual nuclear spin relaxation behavior of water in hardening blast furnace slag mixtures and suggested an explanation for the observed changes in the spin relaxation times based on diffusion effects in inner magnetic field gradients in the paste. Meanwhile, we have succeeded in measuring the self-diffusion coefficient of water in the hardening pastes directly by means of a special pulsed field gradient technique in which the effects of internal magnetic field gradients in a sample can be compensated for. Compared to water self-diffusion in ordinary cement materials, we find a much stronger decrease of the self-diffusion coefficient in the slag based cements. {copyright} 2001 American Institute of Physics.

  13. Resonant Ionization Laser Ion Source (RILIS) With Improved Selectivity Achieved By Ion Pulse Compression Using In-Source Time-of-flight Technique

    SciTech Connect

    Mishin, V. I.; Malinovsky, A. L.; Mishin, D. V. [Institute for Spectroscopy Russian Academy of Sciences, 142190 Troitsk, Moscow region (Russian Federation)

    2009-03-17

    This paper describes for the first time the improved selectivity of the RILIS made possible by the time-of-flight (TOF) ion bunch compression. Brief description of the compression principles and some preliminary experimental results are presented. In the off-line experiments short ion peaks of natural Li, Na, K, Tm and Yb are observed as ions leave the RILIS-TOF structure. For Tm the ion peaks of 5 {mu}s half-height duration are detected and 1 {mu}s peaks for Sn are predicted. In view of the repetition rate of the ISOLDE-RILIS lasers it is hoped that the selectivity of Sn isotopes production may be improved as much as 100 employing the RILIS with the TOF ion bunch compression and a gating technique.

  14. Gaussian-Beam Laser-Resonator Program

    NASA Technical Reports Server (NTRS)

    Cross, Patricia L.; Bair, Clayton H.; Barnes, Norman

    1989-01-01

    Gaussian Beam Laser Resonator Program models laser resonators by use of Gaussian-beam-propagation techniques. Used to determine radii of beams as functions of position in laser resonators. Algorithm used in program has three major components. First, ray-transfer matrix for laser resonator must be calculated. Next, initial parameters of beam calculated. Finally, propagation of beam through optical elements computed. Written in Microsoft FORTRAN (Version 4.01).

  15. Single point contact measurements of mechanical resonances

    Microsoft Academic Search

    C. P. Hsieh; B. T. Khuri-Yakub

    1992-01-01

    A technique for measuring the material properties of spherical objects is presented. The technique is also capable of detecting the presence of surface defects in these objects. Resonances of spheres are excited at both low and high frequencies. Resonances are generated by forming a one-point Hertzian contact between the sphere and a spherical depression in a buffer rod with a

  16. Dynamic tuning of MEMS resonators via electromechanical feedback.

    PubMed

    Norouzpour-Shirazi, Arashk; Hodjat-Shamami, Mojtaba; Tabrizian, Roozbeh; Ayazi, Farrokh

    2015-01-01

    This paper introduces an active electrical technique for dynamic tuning of MEMS resonators. The proposed technique is based on using the resonator output current to generate displacement or acceleration signals by integration or differentiation operations, respectively. The resulting signal is then scaled to generate an appropriate tuning signal. When applied to the resonator through additional signal ports, the tuning signal electrically modifies the equivalent mechanical stiffness or mass of the resonator, thereby tuning the resonance frequency in a bidirectional fashion depending on the polarity of the scaling. This tuning scheme has been applied to a piezoelectric AlN-on-Si BAW square resonator to tune its 14.2 MHz resonance frequency by 22 kHz, equivalent to 1550 ppm. The proposed tuning technique can be applied to a wide range of MEMS resonators and resonant sensors, e.g., to compensate for temperature or process-induced variations in their resonance frequencies. PMID:25585397

  17. Active Resonators for ADMX

    NASA Astrophysics Data System (ADS)

    Malagon, Ana; ADMX Collaboration

    2015-04-01

    The Axion Dark Matter experiment (ADMX) searches for dark matter axion particles converting into detectable photons in a microwave resonator immersed in a strong magnetic field. Here we will discuss a recently proposed technique to use active feedback in resonators as a way to increase the sensitivity of dark matter axion searches. We will briefly overview the theoretical motivation for axions and the current experimental setup of ADMX, then describe the principles of the active feedback system. Finally, we will discuss an active resonator prototype which demonstrates the improvement in signal to noise ratio. Supported by DOE Grants DE-FG02-97ER41029, DE-FG02-96ER40956, DE- AC52-07NA27344, DE-AC03-76SF00098, NSF Grant 1067242, and the Livermore LDRD program.

  18. Near Infrared Surface Plasmon Resonance Phase Imaging and Nanoparticle-Enhanced Surface Plasmon Resonance Phase Imaging

    E-print Network

    Near Infrared Surface Plasmon Resonance Phase Imaging and Nanoparticle-Enhanced Surface Plasmon: The techniques of surface plasmon resonance-phase imaging (SPR-PI) and nanoparticle-enhanced SPR-PI have been tool for biological researchers throughout the world.1,2 Surface plasmon resonance imaging (SPRI

  19. Resonances in Positronium Hydride

    NASA Technical Reports Server (NTRS)

    Drachman, Richard J.; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    Recently, Ho and his colleagues have calculated the positions and widths of a series of resonances in the Ps+H scattering system, using the complex -rotation method and have compared them with estimates that I made many years ago using a quite different technique. I assumed that the resonance mechanism was the existence in the rearrangement channel [e+ + H-] of an infinite series of perturbed Coulomb bound states. Although these must be broadened and shifted by coupling with the open scattering channel, I expected them to lie very close to the actual resonance positions. To verify this, I did a model calculation for S-waves, including the coupling, and found that the first two resonances were not shifted very far from their unperturbed position. The new, detailed calculation agrees with this result, but when the P-wave was examined it was found, surprisingly, that the lowest resonance indeed moved up in energy by a large amount. With the help of Joseph DiRienzi of the College of Notre Dame of Maryland I am now extending the old calculation to P- and D-waves, in an attempt to understand this unexpected energy shift. Results will be presented at the Workshop.

  20. GAUSSIAN BEAM LASER RESONATOR PROGRAM

    NASA Technical Reports Server (NTRS)

    Cross, P. L.

    1994-01-01

    In designing a laser cavity, the laser engineer is frequently concerned with more than the stability of the resonator. Other considerations include the size of the beam at various optical surfaces within the resonator or the performance of intracavity line-narrowing or other optical elements. Laser resonators obey the laws of Gaussian beam propagation, not geometric optics. The Gaussian Beam Laser Resonator Program models laser resonators using Gaussian ray trace techniques. It can be used to determine the propagation of radiation through laser resonators. The algorithm used in the Gaussian Beam Resonator program has three major components. First, the ray transfer matrix for the laser resonator must be calculated. Next calculations of the initial beam parameters, specifically, the beam stability, the beam waist size and location for the resonator input element, and the wavefront curvature and beam radius at the input surface to the first resonator element are performed. Finally the propagation of the beam through the optical elements is computed. The optical elements can be modeled as parallel plates, lenses, mirrors, dummy surfaces, or Gradient Index (GRIN) lenses. A Gradient Index lens is a good approximation of a laser rod operating under a thermal load. The optical system may contain up to 50 elements. In addition to the internal beam elements the optical system may contain elements external to the resonator. The Gaussian Beam Resonator program was written in Microsoft FORTRAN (Version 4.01). It was developed for the IBM PS/2 80-071 microcomputer and has been implemented on an IBM PC compatible under MS DOS 3.21. The program was developed in 1988 and requires approximately 95K bytes to operate.

  1. Frequency response of resonant converters

    Microsoft Academic Search

    K. Siri; C. Q. Lee; S. J. Fang

    1990-01-01

    The general theory of the discrete small-signal analyses of resonant converters has been formulated in a closed form. For simplicity and verification, the state-plane diagram technique is used for the analysis. This theory is applicable to converters in half-bridge or full-bridge configurations when operated in the continuous conduction mode. Using a series resonant converter (SRC) as an example, the analytic

  2. Nuclear magnetic resonance contrast agents

    DOEpatents

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

    1997-12-30

    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.

  3. Analysis of the performance of a phase alternated multiple pulse sequence in spin I = 7/2 zero-field NQR spectroscopy

    NASA Astrophysics Data System (ADS)

    Ramamoorthy, A.

    Zero-field nuclear magnetic resonance spectroscopy of solids containing quadrupole nuclei usually results in broad spectral lines. This line-broadening is due mainly to the inhomogeneity of the electric field gradient (EFG) at the quadrupolar nuclear site. High resolution spectra of such solids can be obtained with the application of suitably designed multiple radiofrequency (RF) pulse sequences. The performance is reported for a periodic and cyclic phase alternated multiple RF pulse sequence (PAPS) in a spin I = 7/2 system in zero external magnetic field. Average Hamiltonian theory based on the Magnus expansion is used to solve the time-dependent Liouville-von Neumann equation of motion of the spin system under the effect of the PAPS sequence. Single transition operators are employed in the spin dynamics calculations. It is shown that the multiple pulse seqeuncearation pulse, suppresses the EFG inhomogeneity to a maximum extent when = 2 . [-- ] 2 , where is the prep1 2 2 N 1 2 1

  4. Techniques for classifying acoustic resonant spectra

    SciTech Connect

    Roberts, R.S.; Lewis, P.S.; Chen, J.T.; Vela, O.A.

    1995-12-31

    A second-generation nondestructive evaluation (NDE) system that discriminates between different types of chemical munitions is under development. The NDE system extracts features from the acoustic spectra of known munitions, builds templates from these features, and performs classification by comparing features extracted from an unknown munition to a template library. Improvements over first-generation feature extraction template construction and classification algorithms are reported. Results are presented on the performance of the system and a large data set collected from surrogate-filled munitions.

  5. Dark resonance

    SciTech Connect

    An, Haipeng; Pospelov, Maxim, E-mail: han@perimeterinstitute.ca, E-mail: mpospelov@perimeterinstitute.ca [Perimeter Institute for Theoretical Physics, Waterloo, ON, N2J 2W9 (Canada)

    2012-11-01

    We construct explicit models of particle dark matter where the attractive force in the dark matter sector creates a narrow near-threshold resonance that qualitatively changes the energy dependence of the annihilation cross section. In these models, the resonant enhancement of the dark matter annihilation can easily source the excess of energetic leptons observed by the PAMELA experiment. The distinct feature of these models is that by construction the enhancement of the annihilation cross section shuts off when the dark matter velocity falls below the typical Milky Way values, thus automatically satisfying constraints on dark matter annihilation imposed by the CMB anisotropies and gamma ray constraints from satellite galaxies. However, the resonant enhancement of annihilation can be probed through the most recent FERMI-LAT constraints on the diffuse galactic gamma ray emission.

  6. Dark Resonance

    E-print Network

    Haipeng An; Maxim Pospelov

    2012-06-11

    We construct explicit models of particle dark matter where the attractive force in the dark matter sector creates a narrow near-threshold resonance that qualitatively changes the energy dependence of the annihilation cross section. In these models, the resonant enhancement of the dark matter annihilation can easily source the excess of energetic leptons observed by experiments on PAMELA and FERMI satellites. The distinct feature of these models is that by construction the enhancement of the annihilation cross section shuts off when the dark matter velocity falls below the typical Milky Way values, thus automatically satisfying constraints on dark matter annihilation imposed by the CMB anisotropies and gamma ray constraints from satellite galaxies.

  7. Magnetic resonance imaging of acquired cardiac disease.

    PubMed Central

    Carrol, C L; Higgins, C B; Caputo, G R

    1996-01-01

    Over the last 15 years, advances in magnetic resonance imaging techniques have increased the accuracy and applicability of cardiovascular magnetic resonance imaging. These advances have improved the utility of magnetic resonance imaging in evaluating cardiac morphology, blood flow, and myocardial contractility, all significant diagnostic features in the evaluation of the patient with acquired heart disease. Utilization of cardiovascular magnetic resonance imaging has been limited, primarily due to clinical reliance upon nuclear scintigraphy and echocardiography. Recent developments in fast and ultrafast imaging should continue to enhance the significance of magnetic resonance imaging in this field. Widespread use of magnetic resonance imaging in the evaluation of the cardiovascular system will ultimately depend upon its maturation into a comprehensive, noninvasive imaging technique for the varying manifestations of acquired heart disease, including cardiomyopathy, ischemic heart disease, and acquired valvular disease. Images PMID:8792545

  8. Superconducting clusters and phase separation in Pr1+xBa2-xCu3O7+?: A 63,65Cu nuclear quadrupole resonance and zero-field NMR study

    NASA Astrophysics Data System (ADS)

    Grévin, B.; Berthier, Y.; Mendels, P.; Collin, G.

    2000-02-01

    We present a study on the effect of the Pr3+ substitution for Ba2+ in the Pr1+xBa2-xCu3O7+? system, where small superconducting fractions have been observed in some of the samples with x in the range 0.1resonance (NQR) and zero-field NMR are reported for the x=0.3 sample Pr1.3Ba1.7Cu3O7+? in which the largest superconducting fraction has been detected below 90 K. 63,65Cu NQR in this sample shows the presence of a fraction of metallic copper in the CuO2 planes and confirms that the substitution of Pr onto Ba sites leads to oxygen interchain sites O(5) occupancy. The existence of two different magnetic Cu(2) sites is evidenced for x=0.3 from the comparison of the Cu(2) zero-field NMR in the x=0 and x=0.3 samples. The whole set of results is interpreted in the framework of a phase separation mechanism in the CuO2 planes induced by the Ba/Pr substitution. Three characteristic domains are involved, in which respectively localized holes are present, no holes are transferred, and mobile holes reside. We present a model where the observed superconductivity is due to a segregation of local defects in the structure which gives a distribution of clusters containing mobile holes. A local weakening of the Pr4f-O2p hybridization by the Pr/Ba substitution is argued to explain the presence of these clusters.

  9. Building Resonance

    NSDL National Science Digital Library

    Jeffrey Barker

    This demonstration of how buildings respond to seismic shaking uses cardboard and stiff paper (such as postcards or computer cards). The effects of building resonance can be found by experimenting with taller and shorter buildings, and varying the frequency of shaking.

  10. Acoustic resonance spectroscopy in nuclear safeguards

    SciTech Connect

    Olinger, C.T.; Lyon, M.J.; Stanbro, W.D.; Mullen, M.F.; Sinha, D.N.

    1993-08-01

    Objects resonate at specific frequencies when mechanically excited. The specific resonance frequencies are a function of shape, size, material of construction, and contents of the object. This paper discusses the use of acoustic resonance spectroscopy (ARS) to monitor containers and detect tampering. Evaluation of this technique is based on simulated storage simulations. Although these simulations show promise for this application of ARS, final evaluation will require actual field testing.

  11. Evaluation of the Chromium Resonance Parameters Including Resonance Parameter Covariance

    SciTech Connect

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

    2011-01-01

    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.

  12. Optical Microspherical Resonators for Biomedical Sensing

    PubMed Central

    Soria, Silvia; Berneschi, Simone; Brenci, Massimo; Cosi, Franco; Conti, Gualtiero Nunzi; Pelli, Stefano; Righini, Giancarlo C.

    2011-01-01

    Optical resonators play an ubiquitous role in modern optics. A particular class of optical resonators is constituted by spherical dielectric structures, where optical rays are total internal reflected. Due to minimal reflection losses and to potentially very low material absorption, these guided modes, known as whispering gallery modes, can confer the resonator an exceptionally high quality factor Q, leading to high energy density, narrow resonant-wavelength lines and a lengthy cavity ringdown. These attractive characteristics make these miniaturized optical resonators especially suited as laser cavities and resonant filters, but also as very sensitive sensors. First, a brief analysis is presented of the characteristics of microspherical resonators, of their fabrication methods, and of the light coupling techniques. Then, we attempt to overview some of the recent advances in the development of microspherical biosensors, underlining a number of important applications in the biomedical field. PMID:22346603

  13. NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts. Quarterly technical progress report, June 15--September 15, 1991

    SciTech Connect

    Not Available

    1991-12-17

    Our previous studies (1,2) on the zerofield NMR spectra of Cu/Co catalysts revealed that the method of preparation sensitively influences the magnetic character of the Catalyst. Catalytic studies of the earlier investigators also (3) show similar influence on the product selectivity and indicate reproducible performance is critically dependent on the control and rigor of the preparation technique. To compliment the NMR results, we have made a thorough investigation of the Hysteresis character of the Cu/Co catalysts with the metal ratio varying from 0.2 to 4.0.

  14. Stochastic resonance in electrical circuits. I. Conventional stochastic resonance

    Microsoft Academic Search

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

    1999-01-01

    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

  15. Microwave and millimeter-wave resonant tunneling diodes

    NASA Technical Reports Server (NTRS)

    Sollner, T. C. L. Gerhard; Brown, Elliott R.; Goodhue, W. D.

    1987-01-01

    Several demonstrated resonant tunneling devices including oscillators, mixers, multiplexers, and a variable negative resistance are discussed. Techniques of the millimeter/submillimeter regime are also discussed.

  16. Nuclear magnetic resonance spectroscopy

    SciTech Connect

    Harris, R.K.

    1986-01-01

    NMR is remarkable in the number of innovations that have appeared and become established within the past five years. This thoroughly up-to-date account of the field explains fundamentals and applications of the NMR phenomenon from the viewpoint of a physical chemist. Beginning with descriptions of basic concepts involved in continuous wave operation, the book goes on to cover spectral analysis, relaxation phenomena, the effects of pulses, the Fourier transform model, double resonance and the effects of chemical exchange and quadrupolar interactions. The book also includes the new techniques for work on solids and for complicated pulse sequences, plus abundant figures and illustrative spectra.

  17. If It's Resonance, What is Resonating?

    ERIC Educational Resources Information Center

    Kerber, Robert C.

    2006-01-01

    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 further…

  18. All-Resonant Control of Superconducting Resonators

    E-print Network

    Frederick W. Strauch

    2012-08-17

    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 signficantly better than existing proposals using the same technology.

  19. LLC resonant converter with two resonant tanks

    Microsoft Academic Search

    Eun-Soo Kim; Joo-Hoon Kim; Kwang-Ho Lee; Yong-Seog Jeon; Jae-Sam Lee; Dong-Young Huh

    2010-01-01

    To cope with the high power density and low cost in switching power supply, LLC resonant converters with the two resonant tank circuits composed of resonance capacitors and two transformers are proposed in this paper. Each transformers used for the proposed resonant circuits are parallel connected in the primary and series connected in the secondary to reduce the current unbalance.

  20. Resonator modeling by field tracing: a flexible approach for fully vectorial laser resonator modeling

    NASA Astrophysics Data System (ADS)

    Asoubar, Daniel; Wyrowski, Frank; Schweitzer, Hagen; Hellmann, Christian; Kuhn, Michael

    2014-05-01

    Nowadays lasers cover a broad spectrum of applications, like laser material processing, metrology and communications. Therefore a broad variety of different lasers, containing various active media and resonator setups, are used to provide high design flexibility. The optimization of such multi-parameter laser setups requires powerful simulation techniques. In literature mainly three practical resonator modeling techniques can be found: Rigorous techniques, e.g. the finite element method (FEM), approximated solutions based on paraxial Gaussian beam tracing by ABCD matrices and the Fox and Li algorithm are used to analyze transversal resonator modes. All of these existing approaches have in common, that only a single simulation technique is used for the whole resonator. In contrast we reformulate the scalar Fox and Li integral equation for resonator eigenmode calculation into a fully vectorial field tracing operator equation. This allows the flexible combination of different modeling techniques in different subdomains of the resonator. The work introduces the basic concepts of field tracing in resonators to calculate vectorial, transversal eigenmodes of stable and unstable resonators.

  1. Near field probe for detecting resonances in EMC application

    Microsoft Academic Search

    Jiang Xiao; Dazhao Liu; David Pommerenke; Wei Huang; Peng Shao; Xiang Li; Jin Min; Giorgi Muchaidze

    2010-01-01

    Resonances degrade the product's EMI or immunity performance at resonance frequencies. Near field scanning techniques, like EMI scanning or susceptibility scanning determine the local behaviour, but fail to connect the local behaviour to the system level behaviour. Resonating structures form part of the coupling paths, i.e., identifying them will aid in understanding system level behaviour of products. In this article,

  2. Surface plasmon resonance shows that type IV pili are

    E-print Network

    Buckling, Angus

    REPORT Surface plasmon resonance shows that type IV pili are important in surface attachment. Here, using the surface analytical technique, surface plasmon resonance (SPR), we follow the attachment; pili; surface plasmon resonance; biofilm formation 1. INTRODUCTION Bacterial attachment is a critical

  3. 14N nuclear quadrupole resonance study of phase transitions of 1M and 2Or polytypes of potassium hexacyanoferrate (III)

    NASA Astrophysics Data System (ADS)

    Murgich, Juan; Abanero, Jose A.; Santana R., Magaly; Capparelli, Mario V.

    1986-11-01

    14N nuclear quadrupole resonance (NQR) frequencies were measured between 77-328 K for simple monoclinic (1M) and orthorhombic (2Or) polytypes of potassium hexacyanoferrate (III) (KFR). A reversible first order transition was found at 133 K for 1M and at 138 K for 2Or polytype. The transition was interpreted in terms of the coupling of a quasisoft rotatory mode with a temperature dependent tilt motion of the complex ion. An irreversible interpolytype transition produced by internal strains was observed in a sample formed by 1M and 2Or polytypes and repeatedly cycled between around 80-140 K and room temperature. Selective broadening of lines observed in only a pair of N atoms of each hexacyanoferrate ion was attributed to the occurrence of one dimensional disorder of neighboring K ions. The disorder disappeared after sample recrystallization. It was found that low crystallization rates produced only the 1M structure while high rates increased the occurrence of the 2Or over 1M polytype and even produced a third polytype. Annealing of KFR for two weeks at 160 °C produced minor changes in polytypic composition thus showing a high energy barrier for interpolytypic conversion. The results obtained in KFR are explained in terms of the theory of order-disorder structures in layered compounds.

  4. Resonance Rings

    NSDL National Science Digital Library

    This is an activity about resonance and where it is found in related to astronomy. Learners will construct two differently sized rings out of file folder paper and tape them to a piece of cardboard. Next, they will shake the cardboard from side to side, which shakes the rings, and observe what happens when the frequency of the shaking is gradually increased. This activity is from the Stanford Solar Center's All About the Sun: Sun and Stars activity guide for Grades 5-8 and can also accompany the Stanford Solar Center's Build Your Own Spectroscope activity.

  5. Direct measurement of the intrinsic linewidth of a resonant state

    NASA Astrophysics Data System (ADS)

    Kobos, Zachary; Reed, Mark

    2015-03-01

    We have applied inelastic electron tunneling spectroscopy (IETS) techniques to a resonantly-coupled system to determine quantitative differences in resonant versus non-resonant IETS. We use as a model system a set of GaAs-AlGaAs resonant tunneling diodes (RTDs)(footnote: with different barrier widths to tune resonant state linewidths and transmission coefficients. Modulation-broadening studies confirm theoretical predictions; however, the thermal dependence is markedly different than expected from classical IETS theory. An analysis of resonance shut-off reveals that the thermal dependence reflects the thermal broadening of the injector and resonant state density of states. Using this analysis, we show that one can extract both the transmission coefficient and the intrinsic linewidth of the resonant state. This is compared for RTDs of different tunneling barrier widths, and we observe the expected increase in resonance width for thinner barriers. This work was supported by the National Science Foundation.

  6. Regenerative feedback resonant circuit

    SciTech Connect

    Jones, A. Mark; Kelly, James F.; McCloy, John S.; McMakin, Douglas L.

    2014-09-02

    A regenerative feedback resonant circuit for measuring a transient response in a loop is disclosed. The circuit includes an amplifier for generating a signal in the loop. The circuit further includes a resonator having a resonant cavity and a material located within the cavity. The signal sent into the resonator produces a resonant frequency. A variation of the resonant frequency due to perturbations in electromagnetic properties of the material is measured.

  7. Functionalized Nanomaterials to Sense Toxins\\/Pollutant Gases Using a Resonant Cavity

    Microsoft Academic Search

    James Roberts; Jai Dahiya; Aman Anand

    2008-01-01

    This paper provides an overview of the techniques and methods involving electromagnetic resonators to study the interactions of gas molecules with substrates. A resonant cavity operating in TE011 mode was employed to characterize the nature of interactions of a range of weakly polar to non-polar gas molecules with carbon nanotubes loaded in the cavity. Resonant cavities are special electromagnetic resonators

  8. Qualitative and Quantitative Evaluation of IGF-1R Kinase Activity Based on Surface Plasmon Resonance Biosensor

    E-print Network

    Hefei Institute of Intelligent Machines

    Resonance Biosensor Xueling Li1 , Minghui-huang2 , Jian-Long Zhao1* , and MengSu Yang1,2** 1 Shanghai resonance biosensor technique was used to study IGF-1R kinase activity on a new peptide substrate derived. The study demonstrated that surface plasmon resonance biosensor as a sensitive real-time technique may

  9. NMR and NQR parameters of ethanol crystal

    E-print Network

    Milinkovic, M

    2012-01-01

    Electric field gradients and chemical shielding tensors of the stable monoclinic crystal phase of ethanol are computed. The projector-augmented wave (PAW) and gauge-including projector-augmented wave (GIPAW) models in the periodic plane-wave density functional theory are used. The crystal data from X-ray measurements, as well as the structures where either all atomic, or only hydrogen atom positions are optimized in the density functional theory are analyzed. These structural models are also studied by including the semi-empirical Van der Waals correction to the density functional theory. Infrared spectra of these five crystal models are calculated.

  10. Multifrequency spin resonance in diamond

    SciTech Connect

    Childress, Lilian; McIntyre, Jean [Department of Physics and Astronomy, Bates College, 44 Campus Ave, Lewiston, Maine 04240 (United States)

    2010-09-15

    Magnetic resonance techniques provide a powerful tool for controlling spin systems, with applications ranging from quantum information processing to medical imaging. Nevertheless, the behavior of a spin system under strong excitation remains a rich dynamical problem. In this paper, we examine spin resonance of the nitrogen-vacancy center in diamond under conditions outside the regime where the usual rotating-wave approximation applies, focusing on effects of multifrequency excitation and excitation with orientation parallel to the spin quantization axis. Strong-field phenomena such as multiphoton transitions and coherent destruction of tunneling are observed in the spectra and analyzed via numerical and analytic theory. In addition to illustrating the response of a spin system to strong multifrequency excitation, these observations may inform techniques for manipulating electron-nuclear spin quantum registers.

  11. Nuclear Magnetic Resonance

    NASA Astrophysics Data System (ADS)

    Reuhs, Bradley L.; Simsek, Senay

    Nuclear magnetic resonance (NMR) spectroscopy is a powerful analytical technique with a wide variety of applications. It may be used for complex structural studies, for protocol or process development, or as a simple quality assay for which structural information is important. It is nondestructive, and high-quality data may be obtained from milligram, even microgram, quantities of sample. Whereas other spectroscopy techniques may be used to determine the nature of the functional groups present in a sample, only NMR spectroscopy can provide the data necessary to determine the complete structure of a molecule. The applicability of NMR to food analysis has increased over the last three decades. In addition to improved instrumentation and much lower costs, very complex and specialized NMR techniques can now be routinely performed by a student or technician. These experiments can be set up with the click of a button/icon, as all the basic parameters are embedded into default experiment files listed in the data/work station software, and the results are obtained in a short time.

  12. Electron-nuclear double resonance.

    PubMed

    Kulik, Leonid; Lubitz, Wolfgang

    2009-01-01

    The application of electron-nuclear double resonance (ENDOR) spectroscopy for the investigation of photosynthetic systems is reviewed. The basic principles of continuous wave and pulse ENDOR are presented. Selected examples of the application of the ENDOR technique for studying stable and transient paramagnetic species, including cofactor radical ions, radical pairs, triplet states, and the oxygen-evolving complex in plant Photosystem II (PSII) are discussed. Limitations and perspectives of ENDOR spectroscopy are outlined. PMID:19184518

  13. Hadronic Resonances from Lattice QCD

    SciTech Connect

    Lichtl, Adam C. [RBRC, Brookhaven National Laboratory, Upton, NY 11973 (United States); Bulava, John; Morningstar, Colin [Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213 (United States); Edwards, Robert; Mathur, Nilmani; Richards, David [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Fleming, George [Yale University, New Haven, CT 06520 (United States); Juge, K. Jimmy [Department of Physics, University of the Pacific, Stockton, CA 95211 (United States); Wallace, Stephen J. [University of Maryland, College Park, MD 20742 (United States)

    2007-10-26

    The determination of the pattern of hadronic resonances as predicted by Quantum Chromodynamics requires the use of non-perturbative techniques. Lattice QCD has emerged as the dominant tool for such calculations, and has produced many QCD predictions which can be directly compared to experiment. The concepts underlying lattice QCD are outlined, methods for calculating excited states are discussed, and results from an exploratory Nucleon and Delta baryon spectrum study are presented.

  14. Magnetic resonance neurography: technical considerations.

    PubMed

    Chhabra, Avneesh; Flammang, Aaron; Padua, Abraham; Carrino, John A; Andreisek, Gustav

    2014-02-01

    Proper performance of magnetic resonance neurography (MRN) is essential not only to make the examination easier to interpret but also for its accurate evaluation. This article outlines the technical considerations of MRN, various imaging pulse sequences available on current scanners, as well as their relative advantages and disadvantages. In addition, a guide to the optimal use of high-resolution and high-contrast MRN technique is provided, which will aid clinicians in attaining a good-quality examination. PMID:24210313

  15. Low-temperature nuclear magnetic resonance investigation of systems frustrated by competing exchange interactions

    NASA Astrophysics Data System (ADS)

    Roy, Beas

    This doctoral thesis emphasizes on the study of frustrated systems which form a very interesting class of compounds in physics. The technique used for the investigation of the magnetic properties of the frustrated materials is Nuclear Magnetic Resonance (NMR). NMR is a very novel tool for the microscopic study of the spin systems. NMR enables us to investigate the local magnetic properties of any system exclusively. The NMR experiments on the different systems yield us knowledge of the static as well as the dynamic behavior of the electronic spins. Frustrated systems bear great possibilities of revelation of new physics through the new ground states they exhibit. The vandates AA'VO(PO4)2 [AA' ? Zn2 and BaCd] are great prototypes of the J1-J2 model which consists of magnetic ions sitting on the corners of a square lattice. Frustration is caused by the competing nearest-neighbor (NN) and next-nearest neighbor (NNN) exchange interactions. The NMR investigation concludes a columnar antiferromagnetic (AFM) state for both the compounds from the sharp peak of the nuclear spin-lattice relaxation rate (1/T1) and a sudden broadening of the 31P-NMR spectrum. The important conclusion from our study is the establishment of the first H-P-T phase diagram of BaCdVO(PO4)2. Application of high pressure reduces the saturation field (HS) in BaCdVO(PO4)2 and decreases the ratio J2/J1, pushing the system more towards a questionable boundary (a disordered ground state) between the columnar AFM and a ferromagnetic ground state. A pressure up to 2.4 GPa will completely suppress HS. The Fe ions in the `122' iron-arsenide superconductors also sit on a square lattice thus closely resembling the J1-J2 model. The 75As-NMR and Nuclear Quadrupole Resonance (NQR) experiments are conducted in the compound CaFe2As2 prepared by two different heat treatment methods (`as-grown' and `annealed'). Interestingly the two samples show two different ground states. While the ground state of the `as-grown' sample shows a non-magnetic collapsed tetragonal phase (with no magnetic fluctuations), the ground state of the `annealed' sample shows a magnetically long-range ordered orthorhombic phase. The temperature dependence of 1/T1 and that of Knight shift showed that the electron correlations completely disappear in the nonsuperconducting collapsed tetragonal phase in `as-grown' sample of CaFe2As2 indicating quenching of Fe moments. The insulating A-site spinel compound CoAl2O4 exhibits frustration due to competing NN and NNN exchange interactions. This compound has been studied for a long time yet there has been a contradiction as to what the ground state of this compound is. The origin of this ambiguity was pointed out to be microstructure effects such as site-inversion between Co and Al. Thus depending on the value of degree of site inversion x [(Co{1-x}Alx)[Al{2-x}Cox]O4], the ground states differ. A very high quality sample was prepared (x ? 0.06) and 27Al and 59Co NMR were performed to study the ground state of this compound. Together with the results from heat capacity, magnetic measurements and neutron diffraction measurements we conclude that the ground state is collinear AFM. We settled a long debated problem for the ground state of CoAl2O4. The compound BiMn2PO6 is a magnetically frustrated system with three-dimensional magnetic ordering. Frustration in this compound is caused by the comparable values of the exchange interactions along the chain, along the rung and in between the ladders. Thus the magnetic structure of this compound is quite complex with the temperature dependence of magnetic susceptibility exhibiting peak at 30 K, a jump at 43 K and a change of slope at 10 K. 31P-NMR study was done on this system to investigate the nature of transitions (if any) at these temperatures. NMR study suggested a long-range AFM transition at 30 K with a sharp peak in 1/T1. No signature of transition at 43 K suggested its origin is extrinsic. Between 10 K and 30 K the NMR spectra proved the existence of a commensurate magnetic order while below 10 K, the shape of

  16. Ion cyclotron resonance cell

    DOEpatents

    Weller, R.R.

    1995-02-14

    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.

  17. Ion cyclotron resonance cell

    DOEpatents

    Weller, Robert R. (Aiken, SC)

    1995-01-01

    An ion cyclotron resonance cell 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.

  18. Thermal response of chalcogenide microsphere resonators

    SciTech Connect

    Ahmad, H; Aryanfar, I; Lim, K S; Chong, W Y; Harun, S W

    2012-05-31

    A chalcogenide microsphere resonator (CMR) used for temperature sensing is proposed and demonstrated. The CMR is fabricated using a simple technique of heating chalcogenide glass and allowing the molten glass to form a microsphere on the waist of a tapered silica fibre. The thermal responses of the CMR is investigated and compared to that of a single-mode-fibre (SMF) based microsphere resonator. It is observed that the CMR sensitivity to ambient temperature changes is 8 times higher than that of the SMF-based microsphere resonator. Heating the chalcogenide microsphere with a laser beam periodically turned on and off shows periodic shifts in the transmission spectrum of the resonator. By injecting an intensity-modulated cw signal through the resonator a thermal relaxation time of 55 ms is estimated.

  19. Strong WW scattering and resonances at LHC

    E-print Network

    J. R. Pelaez

    1997-05-13

    The low energy dynamics of the general strongly interacting symmetry breaking sector can be easily described using effective chiral Lagrangians. Indeed, the enhancement in WW scattering at LHC, that would imply the existence of such an strong interaction, can be described with just two chiral parameters. These techniques have been shown to reproduce remarkably well the low-energy pion-pion scattering data, which follows a similar formalism. In this work we first review the LHC sensitivity to those two chiral parameters (in the hardest case of non-resonant low-energy WW scattering). Later it is shown how we can predict the general resonance spectrum of the strongly interacting symmetry breaking sector. For that purpose, we use the inverse amplitude method which is also very successful reproducing the lightest hadronic resonances from data in the low-energy non resonant region. We thus present an study of the regions in parameter space where one, two or no resonances may appear.

  20. Folded dipole plasmonic resonators.

    PubMed

    Choonee, K; Syms, R R A

    2013-11-01

    A class of folded ordered plasmonic dipole nanoresonators based on insulator-metal-insulator (IMI) slab waveguides is proposed and studied. This work is motivated by the development of a novel fabrication process that avoids the need for direct write nanolithography and instead relies on accessible UV lithography and other top-down parallel fabrication techniques that result in metallic dolmen structures with nanometre sized gaps. In this context, the dolmen geometry consists of two vertical segments supporting a flat horizontal slab. It is shown using frequency domain finite element analysis that such structures, which are essentially folded dipole antennas, resonate in a similar manner to their linear unfolded counterparts. The effect of the likely fabrication features is also studied. PMID:24216810

  1. Gallium nitride nanowire electromechanical resonators

    NASA Astrophysics Data System (ADS)

    Gray, Jason Michael

    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.

  2. Low-loss coupling to dielectric resonators

    NASA Technical Reports Server (NTRS)

    Hearn, C. P.; Bradshaw, E. S.; Trew, R. J.; Hefner, B. B., Jr.

    1991-01-01

    A compilation is presented of experimental observations and arguments concerning the use of dielectric resonators in applications requiring both tight coupling (beta greater than 10) and high unloaded Q, such as low loss bandpass filters. The microstrip coupled dielectric resonator is the primary focus, but an alternative coupling technique is discussed and comparatively evaluated. It is concluded that coupling factors as large as 65 are achievable.

  3. Manual of clinical magnetic resonance imaging

    SciTech Connect

    Heiken, J.P.; Glazer, H.S.; Lee, J.K.T.; Murphy, W.A.; Gado, M.

    1986-01-01

    This work is a guide to conducting magnetic resonance imaging (MRI) examinations. The manual presents specific imaging protocols for various MRI examinations of the body. An introductory section describes the physical principles and techniques of magnetic resonance imaging and describes the most commonly encountered artifacts. Guidelines are offered for selecting imaging protocols and conducting examinations of the head, spine, neck, chest, cardiovascular system, abdomen, pelvis, musculoskeletal system, and breast.

  4. Numerical Investigations of High Pressure Acoustic Waves in Resonators

    NASA Technical Reports Server (NTRS)

    Athavale, Mahesh; Pindera, Maciej; Daniels, Christopher C.; Steinetz, Bruce M.

    2004-01-01

    This presentation presents work on numerical investigations of nonlinear acoustic phenomena in resonators that can generate high-pressure waves using acoustic forcing of the flow. Time-accurate simulations of the flow in a closed cone resonator were performed at different oscillation frequencies and amplitudes, and the numerical results for the resonance frequency and fluid pressure increase match the GRC experimental data well. Work on cone resonator assembly simulations has started and will involve calculations of the flow through the resonator assembly with and without acoustic excitation. A new technique for direct calculation of resonance frequency of complex shaped resonators is also being investigated. Script-driven command procedures will also be developed for optimization of the resonator shape for maximum pressure increase.

  5. Implementation and characterization of meta-resonator antennas

    NASA Astrophysics Data System (ADS)

    Kim, In Kwang; Varadan, Vasundara V.

    2015-04-01

    Metamaterials are artificially engineered microstructures that have strong resonance behavior although their electrical size is very small. Meta-resonator (metamaterial resonator) antennas use the resonance of the metamaterials to reduce the size of radiators and design multiband antennas. A split-ring resonator (SRR) is a well-studied metamaterial structure which obtains negative permittivity and/or permeability in a narrow frequency region. In this paper, metamaterial structures and meta-resonator antennas are designed and simulated using a full wave simulator. 2D metaresonator antennas are fabricated by photolithography and 3D meta-resonator antennas are fabricated by LTCC (Low- Temperature Co-fired Ceramic) technique. A free space measurement system is used to characterize metamaterial samples. Several 2D/3D meta-resonator antennas with SRRs are described.

  6. Characteristic analysis of coupled microstrip patch resonators on ferrimagnetic substrates

    SciTech Connect

    Sun, K. [Department of Technology, Jackson State University, Jackson, Mississippi 39217 (United States)] [Department of Technology, Jackson State University, Jackson, Mississippi 39217 (United States); Chen, Y. [Department of EE, The Hong Kong Polytechnic University (Hong Kong)] [Department of EE, The Hong Kong Polytechnic University (Hong Kong); Barry, W.; Corlett, J. [Center for Beam Physics, Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States)] [Center for Beam Physics, Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States)

    1996-04-01

    This paper is to use the spectral-domain technique to perform characteristic analysis of coupled microstrip patch resonators on ferrimagnetic substrates. Our formulation has been validated by comparing our result with the published data and showing an excellent agreement between them. Numerical computations have been performed to obtain dependence of resonant frequency on patch dimensions, offset and separation between the two patches, thicknesses of ferrimagnetic film and substrate. It has been seen that as the length of the patch increases the resonant frequency decreases. The larger the offset between the two patches the lower the resonant frequency. The separation between the two patches strongly affects the resonant frequency. It is also found that the resonant frequency increases as the width of the patch decreases. For the fixed dimensions, separation and offset, a thinner substrate results in a higher resonant frequency, and in contrast, a thinner ferrimagnetic film results in a lower resonant frequency. {copyright} {ital 1996 American Institute of Physics.}

  7. Opto-electronic oscillators having optical resonators

    NASA Technical Reports Server (NTRS)

    Yao, Xiaotian Steve (Inventor); Maleki, Lutfollah (Inventor); Ilchenko, Vladimir (Inventor)

    2003-01-01

    Systems and techniques of incorporating an optical resonator in an optical part of a feedback loop in opto-electronic oscillators. This optical resonator provides a sufficiently long energy storage time and hence to produce an oscillation of a narrow linewidth and low phase noise. Certain mode matching conditions are required. For example, the mode spacing of the optical resonator is equal to one mode spacing, or a multiplicity of the mode spacing, of an opto-electronic feedback loop that receives a modulated optical signal and to produce an electrical oscillating signal.

  8. Non-Gaussianity from resonant curvaton decay

    E-print Network

    Alex Chambers; Sami Nurmi; Arttu Rajantie

    2010-06-13

    We calculate curvature perturbations in the scenario in which the curvaton field decays into another scalar field via parametric resonance. As a result of a nonlinear stage at the end of the resonance, standard perturbative calculation techniques fail in this case. Instead, we use lattice field theory simulations and the separate universe approximation to calculate the curvature perturbation as a nonlinear function of the curvaton field. For the parameters tested, the generated perturbations are highly non-Gaussian and not well approximated by the usual fNL parameterisation. Resonant decay plays an important role in the curvaton scenario and can have a substantial effect on the resulting perturbations.

  9. Composite resonator vertical cavity laser diode

    SciTech Connect

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

    1998-05-01

    The use of two coupled laser cavities has been employed in edge emitting semiconductor lasers for mode suppression and frequency stabilization. The incorporation of coupled resonators within a vertical cavity laser opens up new possibilities due to the unique ability to tailor the interaction between the cavities. Composite resonators can be utilized to control spectral and temporal properties within the laser; previous studies of coupled cavity vertical cavity lasers have employed photopumped structures. The authors report the first composite resonator vertical cavity laser diode consisting of two optical cavities and three monolithic distributed Bragg reflectors. Cavity coupling effects and two techniques for external modulation of the laser are described.

  10. Advances in resonance based NDT for ceramic components

    NASA Astrophysics Data System (ADS)

    Hunter, L. J.; Jauriqui, L. M.; Gatewood, G. D.; Sisneros, R.

    2012-05-01

    The application of resonance based non-destructive testing methods has been providing benefit to manufacturers of metal components in the automotive and aerospace industries for many years. Recent developments in resonance based technologies are now allowing the application of resonance NDT to ceramic components including turbine engine components, armor, and hybrid bearing rolling elements. Application of higher frequencies and advanced signal interpretation are now allowing Process Compensated Resonance Testing to detect both internal material defects and surface breaking cracks in a variety of ceramic components. Resonance techniques can also be applied to determine material properties of coupons and to evaluate process capability for new manufacturing methods.

  11. (14)N Quadrupole Resonance line broadening due to the earth magnetic field, occuring only in the case of an axially symmetric electric field gradient tensor.

    PubMed

    Aissani, Sarra; Guendouz, Laoučs; Marande, Pierre-Louis; Canet, Daniel

    2015-01-01

    As demonstrated before, the application of a weak static B0 magnetic field (less than 10G) may produce definite effects on the (14)N Quadrupole Resonance line when the electric field gradient tensor at the nitrogen nucleus level is of axial symmetry. Here, we address more precisely the problem of the relative orientation of the two magnetic fields (the static field and the radio-frequency field of the pure NQR experiment). For a field of 6G, the evolution of the signal intensity, as a function of this relative orientation, is in very good agreement with the theoretical predictions. There is in particular an intensity loss by a factor of three when going from the parallel configuration to the perpendicular configuration. By contrast, when dealing with a very weak magnetic field (as the earth field, around 0.5G), this effect drops to ca. 1.5 in the case Hexamethylenetetramine (HMT).This is explained by the fact that the Zeeman shift (due to the very weak magnetic field) becomes comparable to the natural line-width. The latter can therefore be determined by accounting for this competition. Still in the case of HMT, the estimated natural line-width is half the observed line-width. The extra broadening is thus attributed to earth magnetic field. The latter constitutes therefore the main cause of the difference between the natural transverse relaxation time (T2) and the transverse relaxation time derived from the observed line-width (T2(?)). PMID:25910551

  12. Review of mathematical techniques applicable in astrophysical reaction rate theory

    NASA Astrophysics Data System (ADS)

    Mathai, A. M.; Haubold, H. J.

    2002-10-01

    An overview is presented on statistical techniques for the analytic evaluation of integrals for non-resonant, non-resonant depleted, non-resonant cut-off, non-resonant sccreened, and resonant thermonuclear reaction rates. The techniques are based on statistical distribution theory and the theory of Meijer's G-function and Fox's H-function. The implementation of Meijer's G-function in Mathematica constituts an additional utility for analytic manipulations and numerical computation of thermonuclear reaction rate integrals. Recent results in the astrophysical literature related to the use of analytic thermonuclear reaction rates are incorporated.

  13. Localization of Ubiquinone-8 in the Na+-pumping NADH:Quinone Oxidoreductase from Vibrio cholerae*

    PubMed Central

    Casutt, Marco S.; Nedielkov, Ruslan; Wendelspiess, Severin; Vossler, Sara; Gerken, Uwe; Murai, Masatoshi; Miyoshi, Hideto; Möller, Heiko M.; Steuber, Julia

    2011-01-01

    Na+ is the second major coupling ion at membranes after protons, and many pathogenic bacteria use the sodium-motive force to their advantage. A prominent example is Vibrio cholerae, which relies on the Na+-pumping NADH:quinone oxidoreductase (Na+-NQR) as the first complex in its respiratory chain. The Na+-NQR is a multisubunit, membrane-embedded NADH dehydrogenase that oxidizes NADH and reduces quinone to quinol. Existing models describing redox-driven Na+ translocation by the Na+-NQR are based on the assumption that the pump contains four flavins and one FeS cluster. Here we show that the large, peripheral NqrA subunit of the Na+-NQR binds one molecule of ubiquinone-8. Investigations of the dynamic interaction of NqrA with quinones by surface plasmon resonance and saturation transfer difference NMR reveal a high affinity, which is determined by the methoxy groups at the C-2 and C-3 positions of the quinone headgroup. Using photoactivatable quinone derivatives, it is demonstrated that ubiquinone-8 bound to NqrA occupies a functional site. A novel scheme of electron transfer in Na+-NQR is proposed that is initiated by NADH oxidation on subunit NqrF and leads to quinol formation on subunit NqrA. PMID:21885438

  14. High-frequency and multi-mode operation of substrate-free micromembrane resonator

    NASA Astrophysics Data System (ADS)

    Cho, Sungwan; Cho, Myung Rae; Kim, Sang Goon; Suh, Junho; Park, Yun Daniel; Shim, Seung-Bo

    2015-03-01

    Micromemembrane mechanical resonator is fabricated from stoichiometric silicon nitride and its resonant motions are actuated with electrical field gradient pumping method. Using electrical field gradient force by electrode deposited near the suspended structure, micromembrane resonator can be actuated without electrical components on the movable component. We can drive and investigate multiple modes of micromembrane up to 32th mode with 78 MHz resonant frequency by optical measurement technique. This membrane can be applicable to optical system compatible with cavity without external driving technique.

  15. Multipass modes in an open resonator

    NASA Astrophysics Data System (ADS)

    Niziev, V. G.; Grishaev, R. V.; Panchenko, V. Ya

    2015-02-01

    The papers dealing with multipass modes in open stable resonators are reviewed. A numerical model of an axially symmetric resonator is described that permits the properties of multipass modes to be studied in wave approximation. It is shown that for Fresnel numbers larger than unity, multiple reflections of radiation from the stable resonator mirrors lead to sustained quasi-stationary field oscillations in the resonator which are indicative of the essential contribution of multipass modes. The calculations in filling the resonator with the active medium have been performed for two types of lasers: with the on-axis and off-axis gain maxima. Resonator designs are suggested, trajectory selection techniques are considered to provide high-quality radiation at large Fresnel numbers. The confocal resonator properties are analyzed in the context of competition between single-pass and multipass modes. Relying on the results of calculations for multipass mode generation, a critical analysis of the experimental works is presented suggesting a logical explanation for the peculiarities which had not been physically interpreted in the original publications. An advanced understanding of the physics of multipass mode formations allowed us to put forward a special design of stable resonators for the generation of high quality radiation in high-power lasers.

  16. Integral resonator gyroscope

    NASA Technical Reports Server (NTRS)

    Shcheglov, Kirill V. (Inventor); Challoner, A. Dorian (Inventor); Hayworth, Ken J. (Inventor); Wiberg, Dean V. (Inventor); Yee, Karl Y. (Inventor)

    2008-01-01

    The present invention discloses an inertial sensor having an integral resonator. A typical sensor comprises a planar mechanical resonator for sensing motion of the inertial sensor and a case for housing the resonator. The resonator and a wall of the case are defined through an etching process. A typical method of producing the resonator includes etching a baseplate, bonding a wafer to the etched baseplate, through etching the wafer to form a planar mechanical resonator and the wall of the case and bonding an end cap wafer to the wall to complete the case.

  17. Torque detected broad band electron spin resonance

    NASA Astrophysics Data System (ADS)

    El Hallak, Fadi; van Slageren, Joris; Dressel, Martin

    2010-09-01

    We present a novel technique to measure high frequency electron spin resonance spectra in a broad frequency range (30-1440 GHz) with high sensitivity. We use a quasioptical setup with tunable frequency sources to induce magnetic resonance transitions. These transitions are detected by measuring the change in the magnetic torque signal by means of cantilever torque magnetometry. The setup allows tuning of the frequency, magnetic field, polarization, and the angle between the sample and the external magnetic field. We demonstrate the capabilities of this technique by showing preliminary results obtained on a single crystal of an Fe4 molecular nanomagnet.

  18. Progresses on resonance hairpin probe

    NASA Astrophysics Data System (ADS)

    Karkari, Shantanu; Sirse, Nishant; Gogna, Gurusharan Singh; Turner, Miles

    2013-09-01

    This paper briefly reviews the recent developments on resonance hairpin probe as a diagnostic tool for characterizing low temperature electro-negative and strongly magnetized plasmas. As well known the hairpin is capable of measuring absolute values of electron density provided the plasma surrounding the pins is homogeneous and free from adjoining dielectrics. However this is far from reality because of several factors that influence the actual resonance condition such as the proximity of the probes ceramic support and the presence of sheaths around the resonator pins all contributing to the effective permittivity observed by the hairpin. On the other hand dual resonance frequency has been observed in magnetized plasma. The hairpin probe was also applied in conjunction with pulsed laser photo-detachment for measuring time-resolve negative ion density in pulsed-dc magnetron discharge. Recently an independent method based on a pulsed hairpin probe is developed for quantifying electronegative plasma parameters. Using this method both negative ion density and its temperature has been estimated. The results are found to be in good qualitative agreement with those obtained from pulsed photo-detachment technique.

  19. Microfabricated teeter-totter resonator

    DOEpatents

    Adkins, Douglas Ray; Heller, Edwin J.; Shul, Randy J.

    2004-11-23

    A microfabricated teeter-totter resonator comprises a frame, a paddle pivotably anchored to the frame by pivot arms that define an axis of rotation, a current conductor line on a surface of the paddle, means for applying a static magnetic field substantially perpendicular to the rotational axis and in the plane of the paddle, and means for energizing the current conductor line with an alternating current. A Lorentz force is generated by the interaction of the magnetic field with the current flowing in the conductor line, causing the paddle to oscillate about the axis of rotation. The teeter-totter resonator can be fabricated with micromachining techniques with materials used in the integrated circuits manufacturing industry. The microfabricated teeter-totter resonator has many varied applications, both as an actuation device and as a sensor. When used as a chemical sensor, a chemically sensitive coating can be disposed on one or both surfaces of the paddle to enhance the absorption of chemical analytes from a fluid stream. The resulting mass change can be detected as a change in the resonant frequency or phase of the oscillatory motion of the paddle.

  20. Improved acoustic viscosimeter technique. [for determining fluid shear viscosity

    NASA Technical Reports Server (NTRS)

    Fisch, M. R.; Moeller, R. P.; Carome, E. F.

    1976-01-01

    An improved technique has been developed for studies of the shear viscosity of fluids. It utilizes an acoustic resonator as a four-terminal electrical device; the resonator's amplitude response may be determined directly and simply related to the fluid's viscosity. The use of this technique is discussed briefly and data obtained in several fluids is presented.

  1. Single Molecule Electron Paramagnetic Resonance

    NASA Astrophysics Data System (ADS)

    Teeling-Smith, Richelle M.; Johnston-Halperin, Ezekiel; Poirier, Michael G.; Hammel, P. Chris

    2013-03-01

    Electron paramagnetic resonance (EPR) is a powerful spectroscopic tool for studying the dynamics of biomolecular systems. EPR measurements on bulk samples using a commercial X-band spectrometer provide insight into atomic-scale structure and dynamics of ensembles of biomolecules. Separately, single molecule measurements of biomolecular systems allow researchers to capture heterogeneous behaviors that have revealed the molecular mechanisms behind many biological processes. We are merging these two powerful techniques to perform single molecule EPR . In this experiment, we selectively label double-stranded DNA molecules with nitrogen-vacancy (NV) center nanodiamonds and optically detect the magnetic resonance of the NV probe. Shifts and broadening of our EPR peaks indicate the changing position of the attached DNA relative to the applied magnetic field. Using this new technique, we have successfully measured the first EPR spectrum of a single biomolecule. By controlling the geometry of the diamond and the applied magnetic field, we will quantitatively determine the rotational and translational dynamics of single biomolecules. This research provides the foundation for an advanced single molecule magnetic resonance approach to studies of complex biomolecular systems.

  2. MRI (Magnetic Resonance Imaging)

    MedlinePLUS

    ... Criteria for Significant Risk Investigations of Magnetic Resonance Diagnostic Devices - Guidance for Industry and Food and Drug Administration ... the Submission Of Premarket Notifications for Magnetic Resonance Diagnostic Devices (Withdrawn) A Primer on Medical Device Interactions with ...

  3. Baryon Spectroscopy and Resonances

    SciTech Connect

    Robert Edwards

    2011-12-01

    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.

  4. Practical design methodology of auxiliary resonant snubber inverters

    Microsoft Academic Search

    Jih-Sheng Lai

    1996-01-01

    This paper describes the design methodology for auxiliary resonant snubber inverters including ?- and Y-configured auxiliary resonant snubber inverters. The design emphases are resonant circuit components including inductor, capacitor, end switch, DC link capacitor, and control technique. Design optimization can be aimed at high efficiency, high frequency, low dV\\/dt, or compact size. An example of designing a three-phase 100 kVA

  5. Pediatric magnetic resonance imaging

    SciTech Connect

    Cohen, M.D.

    1986-01-01

    This book defines the current clinical potential of magnetic resonance imaging and focuses on direct clinical work with pediatric patients. A section dealing with the physics of magnetic resonance imaging provides an introduction to enable clinicians to utilize the machine and interpret the images. Magnetic resonance imaging is presented as an appropriate imaging modality for pediatric patients utilizing no radiation.

  6. Nuclear Magnetic Resonance

    NASA Astrophysics Data System (ADS)

    Andrew, E. R.

    2009-06-01

    Author's preface; 1. Introduction; 2. Basic theory; 3. Experimental methods; 4. Measurement of nuclear properties and general physical applications; 5. Nuclear magnetic resonance in liquids and gases; 6. Nuclear magnetic resonance in non-metallic solids; 7. Nuclear magnetic resonance in metals; 8. Quadrupole effects; Appendices 1-6; Glossary of symbols; Bibliography and author index; Subject index.

  7. Ovenized microelectromechanical system (MEMS) resonator

    DOEpatents

    Olsson, Roy H; Wojciechowski, Kenneth; Kim, Bongsang

    2014-03-11

    An ovenized micro-electro-mechanical system (MEMS) resonator including: a substantially thermally isolated mechanical resonator cavity; a mechanical oscillator coupled to the mechanical resonator cavity; and a heating element formed on the mechanical resonator cavity.

  8. Interconnected Tile Standing Wave Resonant Oscillator Based Clock Distribution Circuits

    Microsoft Academic Search

    Ayan Mandal; Vinay Karkala; Sunil P. Khatri; Rabi N. Mahapatra

    2011-01-01

    Standing wave oscillators (SWOs) are attractive since they can sustain extremely high oscillation frequencies with very low power consumption due to their resonant nature. In this paper, we present a technique to design a high frequency SWO to cover a large area on an IC. We achieve this by combining two techniques. The first technique increases the area coverage of

  9. Rotational resonance with multiple-pulse scaling in solid-state nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Spencer, Richard G. S.; Fishbein, Kenneth W.; Levitt, Malcolm H.; Griffin, Robert G.

    1994-04-01

    Multiple-pulse techniques are applied to rotational resonance experiments in solid-state nuclear magnetic resonance. The usual rotational resonance condition is satisfied when an integral multiple of the magic-angle spinning speed equals the difference in isotropic chemical shifts of the two members of a homonuclear spin-1/2 pair. We show that sequences of rapid periodic radio-frequency pulses scale and rotate both the Zeeman and dipole-dipole Hamiltonians, leading to a modification of the resonance condition and to the introduction of new, single- and double-quantum, rotational resonances. Experimental results are presented which demonstrate these effects in the spectra of doubly 13C-labeled solids.

  10. Hybrid MEMS Resonators and Oscillators Sunil A. Bhave

    E-print Network

    Afshari, Ehsan

    introduce novel transduction techniques which can improve the motional impedance of MEMS resonators by 1000 requirements of the local oscillators, leading to a 10× reduction in power consumption of direct-conversion-dielectric transduced thickness shear mode MEMS resonators with 807 MHz center frequency, motional impedance RX

  11. Optical Detection of Nuclear Magnetic Resonance in Paramagnetic Ions

    Microsoft Academic Search

    C. W. Thiel

    Methods of optically detecting nuclear magnetic resonance in materials that contain paramagnetic ions exhibiting electronic transitions in the visible or near-visible region of the spectrum are discussed with particular emphasis on the application to the study of crystalline insulators that contain dilute quantities of rare-earth ions. Experimental and theoretical aspects of spectral holeburning techniques (ODNMR), nuclear double resonance methods (PENDOR),

  12. Theory of frequency-modulation spectroscopy of coherent dark resonances

    E-print Network

    Zadkov, Victor

    Theory of frequency-modulation spectroscopy of coherent dark resonances Julia Vladimirova, Boris ABSTRACT Theoretical model for the frequency-modulation spectroscopy of dark resonances is discussed(s) with and without frequency modulation using two simulation techniques--the density matrix and quantum trajectories

  13. Sodium Magnetic Resonance Imaging: From Research to Clinical Use

    E-print Network

    Ouwerkerk, Ronald

    Sodium Magnetic Resonance Imaging: From Research to Clinical Use Ronald Ouwerkerk, PhD INTRODUCTION. Sodium MRI is no longer a stand- alone modality with 1 H MRI used only as a scout image. Instead, 23 Na the properties of this nu- cleus and what imaging techniques can be used to observe it. SODIUM-MAGNETIC RESONANCE

  14. Reduction of motion artifacts in magnetic resonance diffusion imaging

    Microsoft Academic Search

    Archie Chih-Ching Chu

    2000-01-01

    Nuclear magnetic resonance (NMR) diffusion is capable of probing molecular displacement in vivo in a micrometer range. The clinical application of diffusion magnetic resonance imaging (MRI) is used for early detecting acute stroke, and it may be a sensitive monitor of early response to cancer treatments. NMR diffusion techniques are sensitive to Brownian motion, but also enhance bulk-motion artifacts in

  15. Split-resonator integrated-post MEMS gyroscope

    NASA Technical Reports Server (NTRS)

    Bae, Youngsam (Inventor); Hayworth, Ken J. (Inventor); Shcheglov, Kirill V. (Inventor)

    2004-01-01

    A split-resonator integrated-post vibratory microgyroscope may be fabricated using micro electrical mechanical systems (MEMS) fabrication techniques. The microgyroscope may include two gyroscope sections bonded together, each gyroscope section including resonator petals, electrodes, and an integrated half post. The half posts are aligned and bonded to act as a single post.

  16. Resonances In a Box George A. Hagedorn+ Bernhard Meller#

    E-print Network

    Hagedorn, George A.

    and State University, Blacksburg, Virginia 24061--0123, U.S.A. # Facultad de Fâ??ďż˝sica, P.U. Catâ??olica deResonances In a Box George A. Hagedorn+ § Bernhard Meller# ¶ September 26, 1999 + Department mechanics. The technique is called, ``A spherical box approach to resonances,'' by its inventors, Maier et

  17. Resonant Tunneling in Double Bilayer Graphene Heterostructures

    NASA Astrophysics Data System (ADS)

    Fallahazad, Babak; Lee, Kayoung; Kang, Sangwoo; Xue, Jiamin; Larentis, Stefano; Corbet, Christopher; Kim, Kyounghwan; Movva, Hema; Taniguchi, Takashi; Watanabe, Kenji; Register, Leonard; Banerjee, Sanjay; Tutuc, Emanuel

    2015-03-01

    We present the realization and characterization of independently contacted and rotationally aligned double bilayer graphene heterostructures, that show gate-tunable tunneling resonances and negative differential resistance in their interlayer current-voltage characteristics. Our devices are fabricated by successively stacking mechanically exfoliated bilayer graphene and hexagonal boron nitride dielectric using a layer-by-layer transfer technique. The bilayers are rotationally aligned during the device fabrication by selecting flakes with straight edges, and using them as a reference for alignment. We determine the heterostructure energy band alignment at the tunneling resonance using the individual layer carrier densities, and including the chemical potential dependence on the carrier density. Our analysis show that the tunneling resonances occur when the charge neutrality points of the two bilayer graphene are energetically aligned, which suggests the resonances stem from the momentum conserving tunneling. This work has been supported by NRI-SWAN, ONR, and Intel.

  18. Statistical aspects of ultracold resonant scattering

    NASA Astrophysics Data System (ADS)

    Mayle, Michael; Ruzic, Brandon P.; Bohn, John L.

    2012-06-01

    Compared to purely atomic collisions, ultracold collisions involving molecules have the potential to support a much larger number of Fano-Feshbach resonances due to the huge amount of ro-vibrational states available. In order to handle such ultracold atom-molecule collisions, we formulate a theory that incorporates the ro-vibrational Fano-Feshbach resonances in a statistical manner while treating the physics of the long-range scattering, which is sensitive to such things as hyperfine states, collision energy, and any applied electromagnetic fields, exactly within multichannel quantum defect theory. Uniting these two techniques, we can assess the influence of highly resonant scattering in the threshold regime, and in particular its dependence on the hyperfine state selected for the collision. This allows us to explore the onset of Ericson fluctuations in the regime of overlapping resonances, which are well known in nuclear physics but completely unexplored in the ultracold domain.

  19. Direct determination of state-to-state rotational energy transfer rate constants via a Raman-Raman double resonance technique: ortho-acetylene in v2=1 at 155 K

    NASA Astrophysics Data System (ADS)

    Doménech, José L.; Martínez, Raúl Z.; Ramos, Ángel; Bermejo, Dionisio

    2010-04-01

    A new technique for the direct determination of state-to-state rotational energy transfer rate constants in the gas phase is presented. It is based on two sequential stimulated Raman processes: the first one prepares the sample in a single rotational state of an excited vibrational level, and the second one, using the high resolution quasi-continuous stimulated Raman-loss technique, monitors the transfer of population to other rotational states of the same vibrational level as a function of the delay between the pump and the probe stages. The technique is applied to the odd-J rotational states of v2=1 acetylene at 155 K. The experimental layout, data acquisition, retrieval procedures, and numerical treatment are described. The quantity and quality of the data are high enough to allow a direct determination of the state-to-state rate constant matrix from a fit of the experimental data, with the only conditions of detailed balance and of a closed number of states. The matrix obtained from this direct fit is also compared with those obtained using some common fitting and scaling laws.

  20. Resonantly detecting axion-mediated forces with nuclear magnetic resonance.

    PubMed

    Arvanitaki, Asimina; Geraci, Andrew A

    2014-10-17

    We describe a method based on precision magnetometry that can extend the search for axion-mediated spin-dependent forces by several orders of magnitude. By combining techniques used in nuclear magnetic resonance and short-distance tests of gravity, our approach can substantially improve upon current experimental limits set by astrophysics, and probe deep into the theoretically interesting regime for the Peccei-Quinn (PQ) axion. Our method is sensitive to PQ axion decay constants between 10(9) and 10(12) GeV or axion masses between 10(-6) and 10(-3) eV, independent of the cosmic axion abundance. PMID:25361250

  1. Broadband second harmonic generation in whispering gallery mode resonators

    E-print Network

    Lin, Guoping; Strekalov, Dmitry V; Yu, Nan

    2013-01-01

    Optical frequency conversion processes in nonlinear materials are limited in wavelength by the accessible phase matching and the required high pump powers. In this letter, we report a novel broadband phase matching (PM) technique in high quality factor (Q) whispering gallery mode (WGM) resonators made of birefringent crystalline materials. This technique relies on two interacting WGMs, one with constant and the other with spatially oscillating phase velocity. Thus, phase matching occurs cyclically. The technique can be implemented with a WGM resonator with its disk plane parallel to the optic axis of the crystal. With a single beta barium borate (BBO) resonator in that configuration, we experimentally demonstrated efficient second harmonic generation (SHG) to harmonic wavelengths from 780 nm in the near infrared to 317 nm in the ultraviolet (UV). The observed SHG conversion efficiency is as high as 4.6% (mW)-1. This broadband PM technique opens a new way for nonlinear optics applications in WGM resonators. Th...

  2. Model-based reconstruction of magnetic resonance spectroscopic imaging

    E-print Network

    Chatnuntawech, Itthi

    2013-01-01

    Magnetic resonance imaging (MRI) is a medical imaging technique that is used to obtain images of soft tissue throughout the body. Since its development in the 1970s, MRI has gained tremendous importance in clinical practice ...

  3. Novel Detection Schemes of Nuclear Magnetic Resonance and Magnetic Resonance Imaging: Applications from Analytical Chemistry to Molecular Sensors

    Microsoft Academic Search

    Elad Harel; Leif Schröder; Shoujun Xu

    2008-01-01

    Nuclear magnetic resonance (NMR) is a well-established analytical technique in chemistry. The ability to precisely control the nuclear spin interactions that give rise to the NMR phenomenon has led to revolutionary advances in fields as diverse as protein structure determination and medical diagnosis. Here, we discuss methods for increasing the sensitivity of magnetic resonance experiments, moving away from the paradigm

  4. Optical Helmholtz resonators

    NASA Astrophysics Data System (ADS)

    Chevalier, Paul; Bouchon, Patrick; Haďdar, Riad; Pardo, Fabrice

    2014-08-01

    Helmholtz resonators are widely used acoustic components able to select a single frequency. Here, based on an analogy between acoustics and electromagnetism wave equations, we present an electromagnetic 2D Helmholtz resonator made of a metallic slit-box structure. At the resonance, the light is funneled in the ?/800 apertures, and is subsequently absorbed in the cavity. As in acoustics, there is no higher order of resonance, which is an appealing feature for applications such as photodetection or thermal emission. Eventually, we demonstrate that the slit is of capacitive nature while the box behaves inductively. We derive an analytical formula for the resonance wavelength, which does not rely on wave propagation and therefore does not depend on the permittivity of the material filling the box. Besides, in contrast with half-wavelength resonators, the resonance wavelength can be engineered by both the slit aspect ratio and the box area.

  5. Analytical Methods for Characterizing Magnetic Resonance Probes

    PubMed Central

    Manus, Lisa M.; Strauch, Renee C.; Hung, Andy H.; Eckermann, Amanda L.; Meade, Thomas J.

    2012-01-01

    SUMMARY The efficiency of Gd(III) contrast agents in magnetic resonance image enhancement is governed by a set of tunable structural parameters. Understanding and measuring these parameters requires specific analytical techniques. This Feature describes strategies to optimize each of the critical Gd(III) relaxation parameters for molecular imaging applications and the methods employed for their evaluation. PMID:22624599

  6. Rapid Research Note Raman Scattering in Resonance

    E-print Network

    Nabben, Reinhard

    character of the Ga-N bond. Furthermore, this technique was applied to study compositional non-uniformity in the ternary alloy InGaN [4, 5]. However, resonance Raman scattering at bound excitons as reported for Cd a local maximum at 80 K and a main maximum at 130 K. A further temperature increase up to 330 K leads

  7. Magnetic resonance urography in pediatric urology

    Microsoft Academic Search

    Wolfgang H. Cerwinka; J. Damien Grattan-Smith; Andrew J. Kirsch

    2008-01-01

    Purpose of reviewMagnetic resonance urography (MRU) has emerged as a powerful diagnostic tool in the evaluation of the pediatric genitourinary tract. The purpose of this review is to familiarize the reader with the basic techniques, strengths and limitations, as well as the current and potential future applications of MRU in pediatric urology.

  8. Very high frequency EMAT for resonant measurement

    Microsoft Academic Search

    K. Kawashima

    1994-01-01

    Very high frequency resonant EMAT technique is described at frequencies over 200 MHz which is a very high frequency room-temperature measurement of this type. This high frequency EMAT is very small, 25 mm×25 mm×40 mm, and is made from a permanent magnet with 20 mm diameter and a flat circular coil with 3 mm diameter. Longitudinal waves, slow and fast

  9. Parallel magnetic resonance imaging: characterization and comparison 

    E-print Network

    Rane, Swati Dnyandeo

    2005-11-01

    . Echo Planar Imaging (EPI) . . . . . . . . . . . . 11 b.FastSpinEcho(FSE) ............... 12 c. OtherPulseSequences ............... 14 2. ParallelImaging ..................... 14 III PARALLEL MAGNETIC RESONANCE IMAGING ....... 15 A...-SMASH (VD-AUTO-SMASH) . . 22 H.GRAPPA ........................... 23 I. SPACERIP.......................... 24 J. SingleEchoAcquisition(SEA)................ 24 IV CHARACTERIZATION AND COMPARISON OF PARAL- LEL MRI TECHNIQUES ..................... 26 vi CHAPTER...

  10. Analysis techniques

    NASA Technical Reports Server (NTRS)

    Chelton, D.

    1983-01-01

    Analysis techniques for the sea surface temperature (SST) intercomparison were discussed. Systematic differences between various measurement techniques were identified and examined. This in turn might reveal areas for needed improvement in the SST retrieval algorithms or, at the very least, a clearer understanding of the limitations of each sensor.

  11. Brain Magnetic Resonance Spectroscopy Classifiers

    Microsoft Academic Search

    Susana Oliveira; Jaime Rocha; Victor Alves

    2010-01-01

    \\u000a During the last decade, the Magnetic Resonance Spectroscopy modality has become an integrant part of the diagnostic routine.\\u000a However, the visual interpretation of these spectra is difficult and few clinicians are trained to use the technique. In this\\u000a study, sixty-eight spectra obtained from twenty-two multi-voxel spectroscopies were classified using three well-known classification\\u000a algorithms: K-Nearest Neighbors (KNN), Decision Trees and Naďve

  12. Magnetic field-cycling NMR and 14N, 17O quadrupole resonance in the explosive pentaerythritol tetranitrate (PETN)

    Microsoft Academic Search

    John A. S. Smith; Timothy J. Rayner; Michael D. Rowe; Jamie Barras; Neil F. Peirson; Andrew D. Stevens; Kaspar Althoefer

    2010-01-01

    The explosive pentaerythritol tetranitrate (PETN) C(CH2–O–NO2)4 has been studied by 1H NMR and 14N NQR. The 14N NQR frequency and spin–lattice relaxation time T1Q for the ?+ line have been measured at temperatures from 255 to 325K. The 1H NMR spin–lattice relaxation time T1 has been measured at frequencies from 1.8kHz to 40MHz and at temperatures from 250 to 390K.

  13. Magnetic field-cycling NMR and 14N, 17O quadrupole resonance in the explosive pentaerythritol tetranitrate (PETN)

    Microsoft Academic Search

    John A. S. Smith; Timothy J. Rayner; Michael D. Rowe; Jamie Barras; Neil F. Peirson; Andrew D. Stevens; Kaspar Althoefer

    2010-01-01

    The explosive pentaerythritol tetranitrate (PETN) C(CH2-O-NO2)4 has been studied by 1H NMR and 14N NQR. The 14N NQR frequency and spin-lattice relaxation time T1Q for the nu+ line have been measured at temperatures from 255 to 325 K. The 1H NMR spin-lattice relaxation time T1 has been measured at frequencies from 1.8 kHz to 40 MHz and at temperatures from

  14. Effects of spin vacancies on the correlated spin dynamics in La{sub 2}Cu{ital {sub 1{minus}x}}Zn{ital {sub x}}O{sub 4} from {sup 63}Cu nuclear quadrupole resonance relaxation

    SciTech Connect

    Carretta, P.; Rigamonti, A.; Sala, R. [Department of Physics A. Volta, Unita INFM and Sezione INFN, Via Bassi 6, I-27100 Pavia (Italy)] [Department of Physics A. Volta, Unita INFM and Sezione INFN, Via Bassi 6, I-27100 Pavia (Italy)

    1997-04-01

    {sup 63}Cu nuclear quadrupole resonance (NQR) relaxation measurements in La{sub 2}CuO{sub 4} doped Zn are used in order to investigate the temperature dependence of the in-plane magnetic correlation length {xi}{sub 2D} and the effects associated to spin vacancies in two dimensional quantum Heisenberg antiferromagnets (QHAF). The relaxation rates {ital T}{sub 1}{sup {minus}1} and {ital T}{sub 2}{sup {minus}1} have been related to the static generalized susceptibility {chi}({bold q},0) and to the decay rate {Gamma}{bold {sub q}} of the normal excitations. By using scaling arguments for {chi}({bold q},0) and {Gamma}{bold {sub q}}, the relaxation rates have been expressed in close form in terms of {xi}{sub 2D}{ital (x,T)} and its dependence on temperature and spin doping {ital x} thus extracted. The experimental findings are analyzed in light of the renormalized classical (RC) and quantum critical (QC) behaviors predicted for {xi}{sub 2D} by recent theories for {ital S}=1/2 HAF in square lattices. It is first shown that in pure La{sub 2}CuO{sub 4}, {xi}{sub 2D} is consistent with a RC regime up to about 900 K, with tendency toward the QC regime above. The spin vacancies reduce the N{acute e}el temperature according to the law {ital T{sub N}(x){approx}T{sub N}(0)(1{endash}3.5x)}. From the temperature dependence of {sup 63}Cu NQR relaxation rate {ital T}{sub 1}{sup {minus}1}, {ital T}{sub 2}{sup {minus}1} and from the composition dependence of {ital T{sub N}} it is consistently proved that the effect on {xi}{sub 2D} can be accounted for by the modification of the spin stiffness in a simple dilutionlike model, the system still remaining in the RC regime, at least for {ital T}{le}900 K. {copyright} {ital 1997 American Institute of Physics.}

  15. Spin dynamics in CuO and Cu[sub 1[minus][ital x

    SciTech Connect

    Carretta, P.; Corti, M.; Rigamonti, A. (Department of Physics Alessandro Volta,'' University of Pavia, Via Bassi 6, 27100 Pavia (Italy))

    1993-08-01

    [sup 63]Cu nuclear quadrupole resonance (NQR), nuclear antiferromagnetic resonance (AFNMR), and spin-lattice relaxation, as well as [sup 7]Li NMR and relaxation measurements in CuO and in Cu[sub 1[minus][ital x

  16. Adiabatic invariance and transient resonance in very slowly varying oscillatory Hamiltonian systems

    Microsoft Academic Search

    D. L. Bosley; J. Kevorkian

    1990-01-01

    Canonical averaging techniques are applied to very slowly varying oscillatory systems in Hamiltonian standard form to very high orders, which are required for uniformly valid solutions. When resonance is exhibited in these systems N-1 adiabatic invariants are found, reducing the original system of 2N first-order differential equations which embody the resonance behavior. Three examples exhibiting transient resonance are examined. Transient

  17. Advances in Surface Plasmon Resonance Imaging Enable Quantitative Tracking of Nanoscale Changes in Thickness and

    E-print Network

    Dutcher, John

    Advances in Surface Plasmon Resonance Imaging Enable Quantitative Tracking of Nanoscale Changes: To date, detailed studies of the thickness of coatings using surface plasmon resonance have been limited a significant improvement to surface plasmon resonance imaging (SPRi) that allows this sensitive technique

  18. Functionalized Nanomaterials to Sense Toxins\\/Pollutant Gases Using Perturbed Microwave Resonant Cavities

    Microsoft Academic Search

    Aman Anand; J. A. Roberts; J. N. Dahiya

    2008-01-01

    This chapter provides an overview of the techniques and methods involving electromagnetic resonators to study the interactions of gas molecules with nanomaterials substrates. A resonant cavity operating in TE011 mode was employed by the author(s) to characterize the nature of interactions of a range of weakly polar to nonpolar gas molecules with carbon nanotubes loaded in the cavity. Microwave resonant

  19. Resonances on hedgehog manifolds

    E-print Network

    Pavel Exner; Jiri Lipovsky

    2013-02-21

    We discuss resonances for a nonrelativistic and spinless quantum particle confined to a two- or three-dimensional Riemannian manifold to which a finite number of semiinfinite leads is attached. Resolvent and scattering resonances are shown to coincide in this situation. Next we consider the resonances together with embedded eigenvalues and ask about the high-energy asymptotics of such a family. For the case when all the halflines are attached at a single point we prove that all resonances are in the momentum plane confined to a strip parallel to the real axis, in contrast to the analogous asymptotics in some metric quantum graphs; we illustrate it on several simple examples. On the other hand, the resonance behaviour can be influenced by a magnetic field. We provide an example of such a `hedgehog' manifold at which a suitable Aharonov-Bohm flux leads to absence of any true resonance, i.e. that corresponding to a pole outside the real axis.

  20. Large mode radius resonators

    NASA Technical Reports Server (NTRS)

    Harris, Michael R.

    1987-01-01

    Resonator configurations permitting operation with large mode radius while maintaining good transverse mode discrimination are considered. Stable resonators incorporating an intracavity telescope and unstable resonator geometries utilizing an output coupler with a Gaussian reflectivity profile are shown to enable large radius single mode laser operation. Results of heterodyne studies of pulsed CO2 lasers with large (11mm e sup-2 radius) fundamental mode sizes are presented demonstrating minimal frequency sweeping in accordance with the theory of laser-induced medium perturbations.

  1. Resonant Optical Antennas

    Microsoft Academic Search

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

    2005-01-01

    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

  2. Trimming of Microring Resonators

    Microsoft Academic Search

    D. K. Sparacin; J. P. Lock; C. Hong; K. K. Gleason; L. C. Kimerling; J. Michel

    Microring resonators are basic building blocks of photonic circuits, enabling complex functionality for optical systems. However, as micro-ring resonator diameters shrink to less than 10 µm, non-deterministic pattern-transfer errors limit dimensional precision and preclude the fabrication of identical devices across an entire wafer. Thus, the ability to precisely trim microring resonators becomes increasingly important. Microring trimming is typically done by

  3. Thermal Resonance Fusion

    E-print Network

    Bao-Guo Dong

    2015-07-07

    We first show a possible mechanism to create a new type of nuclear fusion, thermal resonance fusion, i.e. low energy nuclear fusion with thermal resonance of light nuclei or atoms, such as deuterium or tritium. The fusion of two light nuclei has to overcome the Coulomb barrier between these two nuclei to reach up to the interacting region of nuclear force. We found nuclear fusion could be realized with thermal vibrations of crystal lattice atoms coupling with light atoms at low energy by resonance to overcome this Coulomb barrier. Thermal resonances combining with tunnel effects can greatly enhance the probability of the deuterium fusion to the detectable level. Our low energy nuclear fusion mechanism research - thermal resonance fusion mechanism results demonstrate how these light nuclei or atoms, such as deuterium, can be fused in the crystal of metal, such as Ni or alloy, with synthetic thermal vibrations and resonances at different modes and energies experimentally. The probability of tunnel effect at different resonance energy given by the WKB method is shown that indicates the thermal resonance fusion mode, especially combined with the tunnel effect, is possible and feasible. But the penetrating probability decreases very sharply when the input resonance energy decreases less than 3 keV, so for thermal resonance fusion, the key point is to increase the resonance peak or make the resonance sharp enough to the acceptable energy level by the suitable compound catalysts, and it is better to reach up more than 3 keV to make the penetrating probability larger than 10^{-10}.

  4. Image restoration using fast Fourier and wavelet transforms

    NASA Astrophysics Data System (ADS)

    Harrod, William J.; Nagy, James G.; Plemmons, Robert J.

    1994-02-01

    Pure nuclear quadrupole resonance (NQR) of 14N nuclei is quite promising as a method for detecting explosives such as RDX and contraband narcotics such as cocaine and heroin in quantities of interest. Pure NQR is conducted without an external applied magnetic field, so potential concerns about damage to magnetically encoded data or exposure of personnel to large magnetic fields are not relevant. Because NQR frequencies of different compounds are quite distinct, we do not encounter false alarms from the NQR signals of other benign materials. We have constructed a proof-of-concept NQR explosives detector which interrogates a volume of 300 liters (10 ft3). With minimal modification to the existing explosives detector, we can detect operationally relevant quantities of (free base) cocaine within the 300-liter inspection volume in 6 seconds. We are presently extending this approach to the detection of heroin base and also examining 14N and 35,37Cl pure NQR for detection of the hydrochloride forms of both materials. An adaptation of this NQR approach may be suitable for scanning personnel for externally carried contraband and explosives. We first outline the basics of the NQR approach, highlighting strengths and weaknesses, and then present representative results for RDX and cocaine detection. We also present a partial compendium of relevant NQR parameters measured for some materials of interest.

  5. Acoustic resonance for nonmetallic mine detection

    SciTech Connect

    Kercel, S.W.

    1998-04-01

    The feasibility of acoustic resonance for detection of plastic mines was investigated by researchers at the Oak Ridge National Laboratory`s Instrumentation and Controls Division under an internally funded program. The data reported in this paper suggest that acoustic resonance is not a practical method for mine detection. Representative small plastic anti-personnel mines were tested, and were found to not exhibit detectable acoustic resonances. Also, non-metal objects known to have strong acoustic resonances were tested with a variety of excitation techniques, and no practical non-contact method of exciting a consistently detectable resonance in a buried object was discovered. Some of the experimental data developed in this work may be useful to other researchers seeking a method to detect buried plastic mines. A number of excitation methods and their pitfalls are discussed. Excitation methods that were investigated include swept acoustic, chopped acoustic, wavelet acoustic, and mechanical shaking. Under very contrived conditions, a weak response that could be attributed to acoustic resonance was observed, but it does not appear to be practical as a mine detection feature. Transfer properties of soil were investigated. Impulse responses of several representative plastic mines were investigated. Acoustic leakage coupling, and its implications as a disruptive mechanism were investigated.

  6. Quantum phase transition of light in the resonator array

    NASA Astrophysics Data System (ADS)

    Wu, Chun-Wang; Gao, Ming; Deng, Zhi-Jiao; Dai, Hong-Yi; Chen, Ping-Xing; Li, Cheng-Zu; Quantum Computation Group of NUDT Team

    2015-03-01

    We give a concrete experimental scheme for engineering the insulator-superfluid transition of light in a one-dimensional (1-D) array of coupled superconducting stripline resonators. In our proposed architecture, the on-site interaction and the photon hopping rate can be tuned independently by adjusting the transition frequencies of the charge qubits inside the resonators and at the resonator junctions, respectively, which permits us to systematically study the quantum phase transition of light in a complete parameter space. By combining the techniques of photon-number-dependent qubit transition and fast read-out of the qubit state using a separate low-Q resonator mode, the statistical property of the excitations in each resonator can be obtained with a high efficiency. An analysis of the various decoherence sources and disorders shows that our scheme can serve as a guide to coming experiments involving a small number of coupled resonators.

  7. MRI of Cartilage: Standard Techniques

    Microsoft Academic Search

    Thomas M. Link

    \\u000a Magnetic resonance imaging (MRI) is the only imaging technique that allows direct visualization of cartilage with sufficient\\u000a contrast. However, cartilage imaging is challenging and MRI needs to be tailored to best visualize cartilage morphology, which\\u000a includes using scanners with adequate field strength, coils which allow high spatial resolution imaging, and optimized imaging\\u000a sequences. Also MRI should not only allow to

  8. MAGNETIC RESONANCE ELASTOGRAPHY: A REVIEW

    PubMed Central

    Mariappan, Yogesh K; Glaser, Kevin J; Ehman, Richard L

    2011-01-01

    Magnetic Resonance Elastography (MRE) is a rapidly developing technology for quantitatively assessing the mechanical properties of tissue. The technology can be considered to be an imaging-based counterpart to palpation, commonly used by physicians to diagnose and characterize diseases. The success of palpation as a diagnostic method is based on the fact that the mechanical properties of tissues are often dramatically affected by the presence of disease processes such as cancer, inflammation, and fibrosis. MRE obtains information about the stiffness of tissue by assessing the propagation of mechanical waves through the tissue with a special magnetic resonance imaging (MRI) technique. The technique essentially involves three steps: generating shear waves in the tissue,acquiring MR images depicting the propagation of the induced shear waves andprocessing the images of the shear waves to generate quantitative maps of tissue stiffness, called elastograms. MRE is already being used clinically for the assessment of patients with chronic liver diseases and is emerging as a safe, reliable and noninvasive alternative to liver biopsy for staging hepatic fibrosis. MRE is also being investigated for application to pathologies of other organs including the brain, breast, blood vessels, heart, kidneys, lungs and skeletal muscle. The purpose of this review article is to introduce this technology to clinical anatomists and to summarize some of the current clinical applications that are being pursued. PMID:20544947

  9. Feedback cooling of a nanomechanical resonator

    E-print Network

    Asa Hopkins; Kurt Jacobs; Salman Habib; Keith Schwab

    2003-02-26

    Cooled, low-loss nanomechanical resonators offer the prospect of directly observing the quantum dynamics of mesoscopic systems. However, the present state of the art requires cooling down to the milliKelvin regime in order to observe quantum effects. Here we present an active feedback strategy based on continuous observation of the resonator position for the purpose of obtaining these low temperatures. In addition, we apply this to an experimentally realizable configuration, where the position monitoring is carried out by a single-electron transistor. Our estimates indicate that with current technology this technique is likely to bring the required low temperatures within reach.

  10. Transformation optics with Fabry-Pérot resonances

    PubMed Central

    Sadeghi, M. M.; Li, Sucheng; Xu, Lin; Hou, Bo; Chen, Huanyang

    2015-01-01

    Transformation optics is a powerful tool to design various novel devices, such as invisibility cloak. Fantastic effects from this technique are usually accompanied with singular mappings, resulting in challenging implementations and narrow bands of working frequencies. Here in this article, Fabry-Pérot resonances in materials of extreme anisotropy are used to design various transformation optical devices that are not only easy to realize but also work well for a set of resonant frequencies (multiple frequencies). As an example, a prototype of a cylindrical concentrator is fabricated for microwaves. PMID:25726924

  11. Decomposition techniques

    USGS Publications Warehouse

    Chao, T.T.; Sanzolone, R.F.

    1992-01-01

    Sample decomposition is a fundamental and integral step in the procedure of geochemical analysis. It is often the limiting factor to sample throughput, especially with the recent application of the fast and modern multi-element measurement instrumentation. The complexity of geological materials makes it necessary to choose the sample decomposition technique that is compatible with the specific objective of the analysis. When selecting a decomposition technique, consideration should be given to the chemical and mineralogical characteristics of the sample, elements to be determined, precision and accuracy requirements, sample throughput, technical capability of personnel, and time constraints. This paper addresses these concerns and discusses the attributes and limitations of many techniques of sample decomposition along with examples of their application to geochemical analysis. The chemical properties of reagents as to their function as decomposition agents are also reviewed. The section on acid dissolution techniques addresses the various inorganic acids that are used individually or in combination in both open and closed systems. Fluxes used in sample fusion are discussed. The promising microwave-oven technology and the emerging field of automation are also examined. A section on applications highlights the use of decomposition techniques for the determination of Au, platinum group elements (PGEs), Hg, U, hydride-forming elements, rare earth elements (REEs), and multi-elements in geological materials. Partial dissolution techniques used for geochemical exploration which have been treated in detail elsewhere are not discussed here; nor are fire-assaying for noble metals and decomposition techniques for X-ray fluorescence or nuclear methods be discussed. ?? 1992.

  12. Potential Antiferromagnetic Fluctuations in Hole-Doped Iron-Pnictide Superconductor Ba1-xKxFe2As2 Studied by 75As Nuclear Magnetic Resonance Measurement0.1143/JPSJ.81.054704

    SciTech Connect

    Hirano, Masanori; Yamada, Yuji; Saito, Taku; Nagashima, Ryo; Konishi, Takehisa; Toriyama, Tatsuya; Ohta, Yukinori; Fukazawa, Hideto; Kohori, Yoh; Furukawa, Yuji; Kihou, Kunihiro; Lee, Chul-Ho; Eisaki, Hiroshi

    2012-04-12

    We have performed 75As nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements on single-crystalline Ba1-xKxFe2As2 for x = 0.27–1. 75As nuclear quadruple resonance frequency (?Q) increases linearly with increasing x. The Knight shift K in the normal state shows Pauli paramagnetic behavior with a weak temperature T dependence. K increases gradually with increasing x. By contrast, the nuclear spin–lattice relaxation rate 1/T1 in the normal state has a strong T dependence, which indicates the existence of large antiferomagnetic (AF) spin fluctuations for all x's. The T dependence of 1/T1 shows a gaplike behavior below approximately 100 K for 0.6 < x < 0.9. This behaviors is well explained by the change in the band structure with the expansion of hole Fermi surfaces and the shrinkage and disappearance of electron Fermi surfaces at the Brillouin zone (BZ) with increasing x. The anisotropy of 1/T1, represented by the ratio of 1/T1ab to 1/T1c, is always larger than 1 for all x's, which indicates that stripe-type AF fluctuations are dominant in this system. The K in the superconducting (SC) state decreases, which corresponds to the appearance of spin-singlet superconductivity. The T dependence of 1/T1 in the SC state indicates a multiple-SC-gap feature. A simple two-gap model analysis shows that the larger superconducting gap gradually decreases with increasing x from 0.27 to 1 and a smaller gap decreases rapidly and nearly vanishes for x > 0.6 where electron pockets in BZ disappear.

  13. Singular boundary resonance with turning point resonance

    SciTech Connect

    Wazwaz, A.M.; Hanson, F.B.

    1986-12-01

    The resonance criteria of the singularly perturbed equation, 1/2epsilonchirho(chi;epsilon)u/sub xx/+chi(a-chi)q(chi;epsilon)u/sub x/=su, are investigated on 0resonance criteria and the associated eigenvalue problem to exponential precision. The eigenvalues can be identified as being dominated by the pure singular point problem, the pure turning point problem or by combinations of the two problems. An asymptotic exponential precision notation is introduced to succinctly express the resonance criteria, given to leading order in epsilon.

  14. Mass spectrometry. [review of techniques

    NASA Technical Reports Server (NTRS)

    Burlingame, A. L.; Kimble, B. J.; Derrick, P. J.

    1976-01-01

    Advances in mass spectrometry (MS) and its applications over the past decade are reviewed in depth, with annotated literature references. New instrumentation and techniques surveyed include: modulated-beam MS, chromatographic MS on-line computer techniques, digital computer-compatible quadrupole MS, selected ion monitoring (mass fragmentography), and computer-aided management of MS data and interpretation. Areas of application surveyed include: organic MS and electron impact MS, field ionization kinetics, appearance potentials, translational energy release, studies of metastable species, photoionization, calculations of molecular orbitals, chemical kinetics, field desorption MS, high pressure MS, ion cyclotron resonance, biochemistry, medical/clinical chemistry, pharmacology, and environmental chemistry and pollution studies.

  15. [Effect on Fermi Resonance by Some External Fields: Investigation of Fermi Resonance According to Raman Spectra].

    PubMed

    Jiang, Xiu-lan; Sun, Cheng-lin; Zhou, Mi; Li, Dong-fei; Men, Zhi-wei; Li, Zuo-wei; Gao, Shu-qin

    2015-03-01

    Fermi resonance is a phenomenon of molecular vibrational coupling and energy transfer occurred between different groups of a single molecule or neighboring molecules. Many properties of Fermi resonance under different external fields, the investigation method of Raman spectroscopy as well as the application of Fermi resonance, etc need to be developed and extended further. In this article the research results and development about Fermi resonance obtained by Raman spectral technique were introduced systematically according to our work and the results by other researchers. Especially, the results of the behaviors of intramolecular and intermolecular Fermi resonance of some molecules under some external fields such as molecular field, pressure field and temperature field, etc were investigated and demonstrated in detail according to the Raman spectra obtained by high pressure DAC technique, temperature variation technique as well as the methods we planed originally in our group such as solution concentration variation method and LCOF resonance Raman spectroscopic technique, and some novel properties of Fermi resonance were found firstly. Concretely, (1) Under molecular field. a. The Raman spectra of C5H5 N in CH3 OH and H2O indicates that solvent effect can influence Fermi resonance distinctly; b. The phenomena of the asymmetric movement of the Fermi resonance doublets as well as the fundamental involved is tuned by the Fermi resonance which had not been found by other methods were found firstly by our variation solution concentration method; c. The Fermi resonance properties can be influenced distinctly by the molecular group reorganization induced by the hydrogen bond and anti-hydrogen bond in solution; d. Fermi resonance can occurred between C7 H8 and m-C8H10, and the Fermi resonance properties behave quite differently with the solution concentration; (2) Under pressure field. a. The spectral lines shift towards high wavenumber with increasing pressure, and frequency difference ? varies with pressure, which induced the change of W; b. The W of ?i + ?4 ?3 of CCl4 in C6H6 decreased more quickly in solution than in pure liquid with increasing pressure and the Fermi resonance disappeared ahead of that in pure liquid, which indicates that the phenomenon of Fermi resonance induced by pressure effect can reveal the mechanism of some solvent effects. (3) Under temperature field. a. The Fermi resonance properties of different molecules behave quite differently with temperature. For an instance, the one of CO2 can be influenced distinctly by temperature, while the one of CS2 behaves no change with temperature. This article offers systematic theoretical and experimental support to the investigation of identification and assignment of molecular spectral line, the confirmation of molecular conformation and conformers, the effect of hydrogen bond on molecular structure and properties, etc. PMID:26117870

  16. Silicon Fishbone-Shaped Resonant-Frequency-Tunable MEMS Resonator

    Microsoft Academic Search

    S. Makita; H. Tanigawa; K. Suzuki

    2007-01-01

    In this study, a silicon fishbone-shaped resonant-frequency-tunable MEMS resonator is designed and fabricated. The resonator can vibrate in larger amplitude than conventional doubly-fixed-beam resonator and resonant frequency characteristic is tunable by selectively choosing exciting electrodes. This new resonator should be useful for wider multi-band frequency applications, for example, reference oscillator of cellular phones and multi-band tunable filters.

  17. Magnetic resonance imaging: prologue

    SciTech Connect

    Jacobson, H.G.

    1987-12-11

    Magnetic resonance imaging is becoming an increasingly important method of diagnostic imaging. This new method can compete with computed tomography for several applications, especially those involving the central nervous system. Magnetic resonance imaging is rapidly evolving, and several advances can be anticipated in the near future.

  18. The Concept of Resonance

    ERIC Educational Resources Information Center

    Truhlar, Donald G.

    2007-01-01

    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…

  19. The resonator handbook

    NASA Technical Reports Server (NTRS)

    Cook, Jerry D.; Zhou, Shiliang

    1993-01-01

    The purpose of this work is to extend resonator theory into the region in which the planar mirror is quite small. Results of the theoretical description are then extended to resonator design and experimental arrangements as discussed in further sections of this work. Finally, a discussion of dielectric measurements for small samples is included as a specific application of this work.

  20. Narrowband resonant transmitter

    DOEpatents

    Hutchinson, Donald P.; Simpson, Marcus L.; Simpson, John T.

    2004-06-29

    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.

  1. Resonant snubber inverter

    DOEpatents

    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

    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.

  2. Resonant snubber inverter

    DOEpatents

    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

    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.

  3. Graphene NanoElectroMechanical Resonators and Oscillators

    NASA Astrophysics Data System (ADS)

    Chen, Changyao

    Made of only one sheet of carbon atoms, graphene is the thinnest yet strongest material ever exist. Since its discovery in 2004, graphene has attracted tremendous research effort worldwide. Guaranteed by the superior electrical and excellent mechanical properties, graphene is the ideal building block for NanoElectroMechanical Systems (NEMS). In the first parts of the thesis, I will discuss the fabrications and measurements of typical graphene NEMS resonators, including doubly clamped and fully clamped graphene mechanical resonators. I have developed a electrical readout technique by using graphene as frequency mixer, demonstrated resonant frequencies in range from 30 to 200 MHz. Furthermore, I developed the advanced fabrications to achieve local gate structure, which led to the real-time resonant frequency detection under resonant channel transistor (RCT) scheme. Such real-time detection improve the measurement speed by 2 orders of magnitude compared to frequency mixing technique, and is critical for practical applications. Finally, I employed active balanced bridge technique in order to reduce overall electrical parasitics, and demonstrated pure capacitive transduction of graphene NEMS resonators. Characterizations of graphene NEMS resonators properties are followed, including resonant frequency and quality factor (Q) tuning with tension, mass and temperatures. A simple continuum mechanics model was constructed to understand the frequency tuning behavior, and it agrees with experimental data extremely well. In the following parts of the thesis, I will discuss the behavior of graphene mechanical resonators in applied magnetic field, i.e. in Quantum Hall (QH) regime. The couplings between mechanical motion and electronic band structure turned out to be a direct probe for thermodynamic quantities, i.e., chemical potential and compressibility. For a clean graphene resonators, with quality factors of 1 x 104, it underwent resonant frequency oscillations as applied magnetic field increases. The chemical potential of graphene shifts smoothly within each LL, causing the resonant frequency to change in an explicit pattern. Between LLs, the finite compressibility caused the resonant frequency changing dramatically. The overall oscillations of resonant frequency with the applied magnetic field could be fitted with only disorder potential as free parameter. Compared with conventional electronic transport technique, such mechanical measurements proven to be a more direct and powerful tool, which we used o study the properties of graphene's ground states in broken symmetry states. In the last part this thesis, I will present the study of graphene NEMS oscillators with positive feedback loop. The demonstrated oscillators are self-sustained (without external radio frequency, RF, stimulus), and the oscillation frequencies can be controlled by tension (i.e., applied gate voltage). I also carefully studied the influence of feedback gain and phase, as well as linewidth compression as function of temperature.

  4. Electron paramagnetic resonance and electron nuclear double resonance spectroscopy at 275 GHz

    Microsoft Academic Search

    Huibrecht Blok

    2006-01-01

    A spectrometer for Electron Paramagnetic Resonance (EPR), operating at the very high microwave frequency of 275 GHz in both continuous wave (cw) and pulsed mode, is described and its capabilities are illustrated. A superconducting magnet provides the magnetic field up to 12 Tesla and experiments are possible between room temperature and 5 K. The system utilizes pseudo-optical techniques to minimize

  5. Hacking Techniques

    Microsoft Academic Search

    Richard Barber

    2001-01-01

    With tales of hacked networks and websites being reported by the media daily, people assume that hacking must be easy. But, in truth, the tools and techniques employed by hackers are extremely complex, utilizing a broad range of technologies. The number of mechanisms for breaking into systems, whatever the objective, is on the increase with new tools emerging continuously. This

  6. Resolving resonances in R-matrix calculations

    NASA Astrophysics Data System (ADS)

    Ramírez, J. M.; Bautista, Manuel A.

    2002-10-01

    We present a technique to obtain detailed resonance structures from R-matrix calculations of atomic cross sections for both collisional and radiative processes. The resolving resonances (RR) method relies on the QB method of Quigley-Berrington (Quigley L, Berrington K A and Pelan J 1998 Comput. Phys. Commun. 114 225) to find the position and width of resonances directly from the reactance matrix. Then one determines the symmetry parameters of these features and generates an energy mesh whereby fully resolved cross sections are calculated with minimum computational cost. The RR method is illustrated with the calculation of the photoionization cross sections and the unified recombination rate coefficients of Fe XXIV, O VI, and Fe XVII. The RR method reduces numerical errors arising from unresolved R-matrix cross sections in the computation of synthetic bound-free opacities, thermally averaged collision strengths and recombination rate coefficients.

  7. (Resonance ionization spectroscopy and its applications)

    SciTech Connect

    Ramsey, J.M.

    1990-10-11

    The Fifth International Symposium in Resonance Ionization Spectroscopy and Its Applications was attended. The Joint Research Centre of the European Communities at Ispra, Italy was also visited. The traveler presented an invited talk, chaired a meeting session and gave an impromptu presentation on how current laser technology limits the development of commercial instrumentation based upon Resonance Ionization Spectroscopy. The conference was truely international with scientists from 19 countries and less than 1/4 from the US. The meeting also provided a health mixture of experimentalists and theoreticians. Technical developments reported included the use of electric field ionization from laser prepared Rydberg states as a way to reduce background signals and commercial development of an optical parametric oscillator for replacing pulsed dye laser. A speaker from the Soviet Union suggested their willingness to market hardware they have developed based upon the resonance ionization technique.

  8. Magnetic resonance imaging mapping of brain function. Human visual cortex

    Microsoft Academic Search

    J. W. Belliveau; K. K. Kwong; D. N. Kennedy; J. R. Baker; C. E. Stern; R. Benson; D. A. Chesler; R. M. Weisskoff; M. S. Cohen; R. B. Tootell; P. T. Fox; T. J. Brady

    1992-01-01

    Magnetic resonance imaging (MRI) studies of human brain activity are described. Task-induced changes in brain cognitive state were measured using high-speed MRI techniques sensitive to changes in cerebral blood volume (CBV), blood flow (CBF), and blood oxygenation. These techniques were used to generate the first functional MRI maps of human task activation, by using a visual stimulus paradigm. The methodology

  9. Fabrication of cubic micron-scale 3D metamaterial resonators.

    SciTech Connect

    Sinclair, Michael B.; Brener, Igal; Wendt, Joel Robert; Burckel, David Bruce; Ten Eyck, Gregory A.

    2010-06-01

    We present a new fabrication technique called Membrane Projection Lithography for the production of three-dimensional metamaterials at infrared wavelengths. Using this technique, multilayer infrared metamaterials that include both in-plane and out-of-plane resonators can be fabricated.

  10. A vibration energy harvesting device with bidirectional resonance frequency tunability

    Microsoft Academic Search

    Vinod R Challa; M G Prasad; Yong Shi; Frank T Fisher

    2008-01-01

    Vibration energy harvesting is an attractive technique for potential powering of wireless sensors and low power devices. While the technique can be employed to harvest energy from vibrations and vibrating structures, a general requirement independent of the energy transfer mechanism is that the vibration energy harvesting device operate in resonance at the excitation frequency. Most energy harvesting devices developed to

  11. LABCOM resonator Phase 3

    SciTech Connect

    Keres, L.J.

    1990-11-01

    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.

  12. A bandwidth enhancement technique for mobile handset antennas using wavetraps

    Microsoft Academic Search

    Peter Lindberg; E. Ojefors

    2006-01-01

    A novel technique for enhancing the impedance bandwidth of wireless terminal antennas is presented. By introducing resonant short circuit transmission lines to the long sides of the chassis edges, an effective electrical shortening of the terminal ground plane is achieved. This effect has been used to realize terminal ground planes with resonant lengths at high frequencies, such as GSM 1800\\/1900

  13. Synthesis techniques for some tunable notch filter topologies

    Microsoft Academic Search

    Sacid Oruc; Bulent Alicioglu; N. Yildirim

    2010-01-01

    Synthesis techniques are described for two different tunable microwave notch filter topologies with two resonators. Notch is obtained by first forming an All Pass circuit by cross-coupling input and output ports of either a BSF or a BPF with a transmission line and then detuning capacitors of the two resonators. The previous works on such designs were involving manual tuning

  14. Combined neutron imaging techniques for cultural heritage purpose

    SciTech Connect

    Materna, T. [Institut Laue-Langevin, 6, rue J. Horowitz, BP 156, 38042 Grenoble Cedex 9 (France)

    2009-01-28

    This article presents the different new neutron techniques developed by the Ancient Charm collaboration to image objects of cultural heritage importance: Prompt-gamma-ray activation imaging (PGAI) coupled to cold/thermal neutron transmission tomography, Neutron Resonance Capture Imaging (NRCI) and Neutron Resonance Tomography.

  15. 35-Cl nuclear quadrupole resonance spectra in diazepam and its 1:1 complex with chloral hydrate

    NASA Astrophysics Data System (ADS)

    Brisson, Colette; Durand, Marcel; Jugie, Gérard; Pasdeloup, Maurice

    1980-11-01

    The 35-Cl NQR spectra of diazepam and some of its related compounds are reported; they yield information about the hydrogen bonded complex that diazepam forms with chloral hydrate. The results reflect large changes in electron distribution at the CCl 3 group while the diazepam chlorine at the 7 position remains almost unaffected.

  16. Resonant optical antennas.

    PubMed

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

    2005-06-10

    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 that take into account the finite metallic conductivity at optical frequencies. Because optical antennas link propagating radiation and confined/enhanced optical fields, they should find applications in optical characterization, manipulation of nanostructures, and optical information processing. PMID:15947182

  17. Spin Resonance Strength Calculations

    SciTech Connect

    Courant, E. D. [Brookhaven National Laboratory, Upton NY 11973 (United States)

    2009-08-04

    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.

  18. Nanofabrication Techniques

    NSDL National Science Digital Library

    This page from Foothill-De Anza Community College describes a course on nanoscience for those who need an introduction to the subject. This course is the fifth in a five course series that leads to a certificate in nanoscience, nanotechnology, and nanomaterials engineering. Students will obtain a survey of fabrication techniques as well as "hands-on experience creating thin film materials, and quality control 'shadowing' in a clean energy technology fabrication facility." The projects required by the class are also described.

  19. Densitometry Techniques

    Microsoft Academic Search

    Sydney Lou Bonnick; RADIOGRAPHIC ABSORPTIOMETRY

    \\u000a Clinical densitometry is relatively new but densitometry itself is actually quite old. It was first described over 100 years\\u000a ago in the field of dental radiology as dentists attempted to quantify the bone density in the mandible(1,2). With today’s\\u000a techniques bone density can be quantified in almost every region of the skeleton. The extraordinary technical advances in\\u000a recent years have

  20. Electrochemical Techniques

    SciTech Connect

    Chen, Gang; Lin, Yuehe

    2008-07-20

    Sensitive and selective detection techniques are of crucial importance for capillary electrophoresis (CE), microfluidic chips, and other microfluidic systems. Electrochemical detectors have attracted considerable interest for microfluidic systems with features that include high sensitivity, inherent miniaturization of both the detection and control instrumentation, low cost and power demands, and high compatibility with microfabrication technology. The commonly used electrochemical detectors can be classified into three general modes: conductimetry, potentiometry, and amperometry.

  1. Measurement techniques

    SciTech Connect

    Willis, W.L.

    1980-10-01

    The discussion will be restricted to measurements of voltage and current. Also, although the measurements themselves should be as quantitative as possible, the discussion is rather nonquantitative. Emphasis is on types of instruments, how they may be used, and the inherent advantages and limitations of a given technique. A great deal of information can be obtained from good, clean voltage and current data. Power and impedance are obviously inherent if the proper time relationships are preserved. Often an associated, difficult-to-determine, physical event can be evaluated from the V-I data, such as a time-varying load characteristic, or the time of light emission, etc. The lack of active high voltage devices, such as 50-kV operational amplifiers, restricts measurement devices to passive elements, primarily R and C. There are a few more exotic techniques that are still passive in nature. There are several well-developed techniques for voltage measurements. These include: spark gaps; electrostatic meters; capacitive dividers; mixed RC dividers; and the electro-optic effect. Current is measured by either direct measurement of charge flow or by measuring the resulting magnetic field.

  2. High temperature resonant ultrasound spectroscopy methods

    NASA Astrophysics Data System (ADS)

    Li, Guangyan; Lamberton, Gary; Gladden, Josh

    2008-03-01

    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, placed in a tube furnace, and the transducers with buffer rods made of low acoustic attenuation materials with good thermal stability such as ceramic alumina or fused quartz. Tests on stainless steel demonstrated that the system has the ability of acquiring resonance signals at temperatures up to 800C. Experimental issues such as additional resonance peaks introduced by the buffer rods and sample loading will be addressed. The apparatus has been used to study high temperature elastic properties of p-zintl thermoelectrics, single crystal quartz, a novel piezoelectric material kepertite, and the glass transition around 400C in bulk metallic glass compounds. Good results from these studies and high temperature test runs of aluminum and stainless steel demonstrate the potential for RUS measurements at elevated temperatures.

  3. Evaluations of Resonance Parameters and Resonance Integral of Tungsten

    NASA Astrophysics Data System (ADS)

    Moinul Haque Meaze, A. K. M.

    2007-03-01

    I present evaluated values of resonance parameters and resonance integral for natural tungsten on the basis of experimental transmissions data obtained at the Pohang Neutron Facility (PNF), Republic of Korea. Resonance parameters were obtained by using the Bayesian code SAMMY. The output values of SAMMY were used to evaluate the resonance integral for the capture cross-section.

  4. Parametric resonance and Hopf bifurcation analysis for a MEMS resonator

    E-print Network

    Hulshof, Joost

    Parametric resonance and Hopf bifurcation analysis for a MEMS resonator Cas van der Avoort , Rein van der Hout , and Joost Hulshof January 18, 2010 Abstract We study the response of a MEMS resonator with experimental observations. Keywords MEMS resonator, clipping, beating, Hopf bifurcation. 1 Introduction

  5. Introduction: quantum resonances Classical and quantum mechanics

    E-print Network

    Ramond, Thierry

    : quantum resonances Classical and quantum mechanics Microlocal analysis Resonances associated;..... . .... . .... . ..... . .... . .... . .... . ..... . .... . .... . .... . ..... . .... . .... . .... . ..... . .... . ..... . .... . .... . Introduction: quantum resonances Classical and quantum mechanics Microlocal analysis Resonances associated with homoclinic orbits Outline Introduction: quantum resonances Classical and quantum mechanics Microlocal

  6. Resonances in Positronium Hydride

    NASA Technical Reports Server (NTRS)

    DiRienzi, Joseph; Drachman, Richard J.; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    We re-examine the problem of calculating the positions and widths of the lowest-lying resonances in the Ps + H scattering system which consists of two electrons, one positron and one proton. The first of these resonances, for L=0, was found by the methods of complex rotation and stabilization, and later described as a Feshbach resonance lying close to a bound state in the closed-channel e (+) + H (-) system. Recently, results for the L=1 and 2 scattering states were published, and it was found, surprisingly, that there is a larae shift in the positions of these resonances. In this work we repeat the analysis for L=1 and find an unexpected explanation for the shift.

  7. Micro-machined resonator

    DOEpatents

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

    1993-03-30

    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.

  8. Resonant ultrasound spectroscopy

    DOEpatents

    Migliori, Albert (Santa Fe, NM)

    1991-01-01

    A resonant ultrasound spectroscopy method provides a unique characterization of an object for use in distinguishing similar objects having physical differences greater than a predetermined tolerance. A resonant response spectrum is obtained for a reference object by placing excitation and detection transducers at any accessible location on the object. The spectrum is analyzed to determine the number of resonant response peaks in a predetermined frequency interval. The distribution of the resonance frequencies is then characterized in a manner effective to form a unique signature of the object. In one characterization, a small frequency interval is defined and stepped though the spectrum frequency range. Subsequent objects are similarly characterized where the characterizations serve as signatures effective to distinguish objects that differ from the reference object by more than the predetermined tolerance.

  9. Exact solution of resonant modes in a rectangular resonator.

    PubMed

    Wu, Jiu Hui; Liu, A Q

    2006-06-01

    The resonant modes of rectangular two-dimensional optical resonators were analyzed exactly. Based on the characteristics of the Bessel function, the resonant frequencies of the rectangular microcavities are expressed in a simple way. In addition, a simple rule to judge when the finite length of a rectangular resonator can be considered infinite is given in realistic applications. The solution that is presented should be useful in possible applications of the rectangular resonators as filters for dense wavelength-division multiplexing. PMID:16688273

  10. Ferromagnetic Resonance Absorption in Magnetite Single Crystals

    Microsoft Academic Search

    L. R. Bickford

    1950-01-01

    The microwave resonance absorption technique, at both 1.25 and 3.3 cm wave-lengths, was used to study the ferromagnetic crystalline anisotropy characteristics and g-factor of magnetite Fe3O4. The experiments were performed on single crystals, both synthetic and natural, from room temperature to -195°C. Depending upon the temperature, magnetite single crystals were found to have magnetic anisotropy characteristics similar to those of

  11. Localized Surface Plasmon Resonance Spectroscopy and Sensing

    Microsoft Academic Search

    Katherine A. Willets; Richard P. Van Duyne

    2007-01-01

    Localized surface plasmon resonance (LSPR) spectroscopy of metal- lic nanoparticles is a powerful technique for chemical and biologi- cal sensing experiments. Moreover, the LSPR is responsible for the electromagnetic-field enhancement that leads to surface-enhanced Raman scattering (SERS) and other surface-enhanced spectroscopic processes. This review describes recent fundamental spectroscopic studies that reveal key relationships governing the LSPR spectral lo- cation and

  12. Magnetic resonance urography: a pictorial overview

    Microsoft Academic Search

    R Garcia-Valtuille; A I GARCIA-VALTUILLE; F ABASCAL; L CEREZAL; M C ARGUELLO

    2006-01-01

    Magnetic resonance urography (MRU) can be performed on the basis of two different imaging strategies: static-fluid MRU, based on heavily T2 weighted turbo spin echo (TSE) sequences, and gadolinium-enhanced excretory MRU. Both MR urographic techniques in combination with standard MRI permit a comprehensive examination of the entire urinary tract. This pictorial review illustrates the MRU features of the a wide

  13. Structural magnetic resonance imaging in epilepsy

    Microsoft Academic Search

    Karel Deblaere; Eric Achten

    2008-01-01

    Because of its sensitivity and high tissue contrast, magnetic resonance imaging (MRI) is the technique of choice for structural\\u000a imaging in epilepsy. In this review the effect of using optimised scanning protocols and the use of high field MR systems\\u000a on detection sensitivity is discussed. Also, the clinical relevance of adequate imaging in patients with focal epilepsy is\\u000a highlighted. The

  14. Silicon carbide microdisk resonator.

    PubMed

    Lu, Xiyuan; Lee, Jonathan Y; Feng, Philip X-L; Lin, Qiang

    2013-04-15

    We demonstrate a silicon carbide (SiC) microdisk resonator with an intrinsic optical quality factor of 6.19×10(3), fabricated on the 3C-SiC-on-Si platform. We characterize the temperature dependence of the cavity resonance and obtain a thermo-optic coefficient of 2.92×10(-5)/K for 3C-SiC. Our simulations show that the device exhibits great potential for cavity optomechanical applications. PMID:23595466

  15. Resonant dielectric metamaterials

    DOEpatents

    Loui, Hung; Carroll, James; Clem, Paul G; Sinclair, Michael B

    2014-12-02

    A resonant dielectric metamaterial comprises a first and a second set of dielectric scattering particles (e.g., spheres) having different permittivities arranged in a cubic array. The array can be an ordered or randomized array of particles. The resonant dielectric metamaterials are low-loss 3D isotropic materials with negative permittivity and permeability. Such isotropic double negative materials offer polarization and direction independent electromagnetic wave propagation.

  16. Structure of proton resonances

    SciTech Connect

    Kraft, O.E.; Naumov, Y.V.; Sigalov, V.M.; Sizov, I.V.

    1986-11-01

    Experimental data are presented which attest to the nonstatistical nature of proton resonances for excitation energies 6--15 MeV in light and intermediate nuclei. The reduced proton widths and the absolute-width and amplitude correlations are analyzed. Special attention is devoted to the amplitude relative-phase correlations. At the end of the review a possible reason for the manifestation of the nonstatistical nature of proton resonances is discussed.

  17. Hexagonal quartz resonator

    DOEpatents

    Peters, Roswell D. M. (Rustburg, VA)

    1982-01-01

    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.

  18. Injector with integrated resonator

    DOEpatents

    Johnson, Thomas Edward; Ziminsky, Willy Steve; York, William David; Stevenson, Christian Xavier

    2014-07-29

    The system may include a turbine engine. The turbine engine may include a fuel nozzle. The fuel nozzle may include an air path. The fuel nozzle may also include a fuel path such that the fuel nozzle is in communication with a combustion zone of the turbine engine. Furthermore, the fuel nozzle may include a resonator. The resonator may be disposed in the fuel nozzle directly adjacent to the combustion zone.

  19. Quantum stochastic resonance

    SciTech Connect

    Loefstedt, R.; Coppersmith, S.N. (AT T Bell Laboratories, Murray Hill, New Jersey 07974 (United States))

    1994-03-28

    We demonstrate that stochastic resonance, where an increase in the noise acting on a nonlinear dynamical system increases the signal-to-noise ratio describing the response to periodic driving, can occur in quantum systems as well as classical ones. We show that quantum stochastic resonance can be observed experimentally by measuring conductance fluctuations in mesoscopic metals and describe the experimental parameters for which it occurs.

  20. Nuclear magnetic resonance gyroscope

    SciTech Connect

    Grover, B.C.

    1984-02-07

    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.