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Sample records for resonance nqr experiments

  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. |

    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. Multi-Frequency Resonances in Pure Multiple-Pulse NQR

    NASA Astrophysics Data System (ADS)

    Furman, G. B.; Kibrik, G. E.; Polyakov, A. Yu.

    2004-12-01

    We have observed multi-frequency resonances in a system with a spin 3/2 irradiated simultaneously by a multiple-pulse radiofrequency sequence and a low frequency field swept in the range 0 ÷ 80 kHz. The theoretical description of the effect is presented using both the rotating frame approximation and the Floquet theory. Both approaches give indentical results at the calculation of the resonance frequencies, transition probabilities and shifts of resonance frequency. The calculated magnetization vs. the frequency of the low-frequency field agrees with the obtained experimental data.

  5. Two-dimensional NQR using ultra-broadband electronics

    NASA Astrophysics Data System (ADS)

    Mandal, S.; Song, Y.-Q.

    2014-03-01

    We have recently developed an ultra-broadband instrument that can effectively excite and detect NMR and NQR signals over a wide frequency range. Our current system operates between 100 kHz and 3.2 MHz using an un-tuned sample coil. The major benefits of this instrument compared to conventional NQR/NMR systems include increased robustness, ease of use (in particular for multi-frequency experiments), and elimination of the need for tuning adjustments in the hardware. Here we describe its use for performing two-dimensional (2D) scans, which allow improved interpretation of complex NQR spectra by detecting the connected resonances. Our method relies on population transfers between the three energy levels of spin-1 nuclei (such as 14N) by using multi-frequency excitation and a single RF coil. Experimental results on pure samples and mixtures are also presented.

  6. NQR investigation and characterization of cocrystals and crystal polymorphs

    NASA Astrophysics Data System (ADS)

    Seliger, Janez; Žagar, Veselko; Asaji, Tetsuo

    2013-05-01

    The application of 14N NQR to the study of cocrystals and crystal polymorphs is reviewed. In ferroelectric and antiferroelectric organic cocrystals 14N NQR is used to determine proton position in an N-H...O hydrogen bond and proton displacement below TC. In cocrystal isonicitinamide - oxalic acid (2:1) 14N NQR is used to distinguish between two polymorphs and to determine the type of the hydrogen bond (N-...H-O). The difference in the 14N NQR spectra of cocrystal formers and cocrystal is investigated in case of carbamazepine, saccharin and carbamazepine - saccharin (1:1). The experimental resolution allows an unambiguous distinction between the 14N NQR spectrum of the cocrystal and the 14N NQR spectra of the cocrystal formers. The possibility of application of NQR and double resonance for the determination of the inhomogeneity of the sample and for the study of the life time of an unstable polymorph is discussed.

  7. Double Resonance Detection of (Mainly Nitrogen) Nqr Frequencies in Explosives and Drugs

    NASA Astrophysics Data System (ADS)

    Seliger, Janez; Žagar, Veselko

    Various nuclear quadrupole double resonance techniques, useful in the detection of nuclear quadrupole resonance frequencies in explosives and drugs, are reviewed with a special emphasis on the detection of 14N and 17O. Various techniques, as for example, The Slusher and Hahn's technique

  8. Application of a dc SQUID to rf amplification: NQR

    SciTech Connect

    Hilbert, C.; Clarke, J.; Sleator, T.; Hahn, E.L.

    1985-05-01

    Superconducting QUantum Interference Devices (SQUIDs) have been used for more than a decade for the detection of magnetic resonance. Until recently, these devices had mostly been confined to operation in the audiofrequency range, so that experiments have been restricted to measurements of resonance at low frequencies, or of changes in the static susceptibility of a sample induced by rf irradiation at the resonant frequency. However, the recent extension of the operating range of low noise dc SQUIDs to radiofrequencies (rf) allows one to detect magnetic resonance directly at frequencies up to several hundred megahertz. In this paper, we begin by summarizing the properties of dc SQUIDs as tuned rf amplifers. We then describe first, the development of a SQUID system for the detection of pulsed nuclear quadrupole resonance (NQR) at about 30 MHz and second, a novel technique for observing magnetic resonances in the absence of any externally applied rf fields.

  9. 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.

  10. SQUID detected NMR and NQR. Superconducting Quantum Interference Device.

    PubMed

    Augustine, M P; TonThat, D M; Clarke, J

    1998-03-01

    The dc Superconducting QUantum Interference Device (SQUID) is a sensitive detector of magnetic flux, with a typical flux noise of the order 1 muphi0 Hz(-1/2) at liquid helium temperatures. Here phi0 = h/2e is the flux quantum. In our NMR or NQR spectrometer, a niobium wire coil wrapped around the sample is coupled to a thin film superconducting coil deposited on the SQUID to form a flux transformer. With this untuned input circuit the SQUID measures the flux, rather than the rate of change of flux, and thus retains its high sensitivity down to arbitrarily low frequencies. This feature is exploited in a cw spectrometer that monitors the change in the static magnetization of a sample induced by radio frequency irradiation. Examples of this technique are the detection of NQR in 27Al in sapphire and 11B in boron nitride, and a level crossing technique to enhance the signal of 14N in peptides. Research is now focused on a SQUID-based spectrometer for pulsed NQR and NMR, which has a bandwidth of 0-5 MHz. This spectrometer is used with spin-echo techniques to measure the NQR longitudinal and transverse relaxation times of 14N in NH4ClO4, 63+/-6 ms and 22+/-2 ms, respectively. With the aid of two-frequency pulses to excite the 359 kHz and 714 kHz resonances in ruby simultaneously, it is possible to obtain a two-dimensional NQR spectrum. As a third example, the pulsed spectrometer is used to study NMR spectrum of 129Xe after polariza-tion with optically pumped Rb. The NMR line can be detected at frequencies as low as 200 Hz. At fields below about 2 mT the longitudinal relaxation time saturates at about 2000 s. Two recent experiments in other laboratories have extended these pulsed NMR techniques to higher temperatures and smaller samples. In the first, images were obtained of mineral oil floating on water at room temperature. In the second, a SQUID configured as a thin film gradiometer was used to detect NMR in a 50 microm particle of 195Pt at 6 mT and 4.2 K. PMID:9650797

  11. NQR Characteristics of an RDX Plastic Explosives Simulant.

    PubMed

    Turecek, J; Schwitter, B; Miljak, D; Stancl, M

    2012-12-01

    For reliable detection of explosives, a combination of methods integrated within a single measurement platform may increase detection performance. However, the efficient field testing of such measurement platforms requires the use of inexplosive simulants that are detectable by a wide range of methods. Physical parameters such as simulant density, elemental composition and crystalline structure must closely match those of the target explosive. The highly discriminating bulk detection characteristics of nuclear quadrupole resonance (NQR) especially constrain simulant design. This paper describes the development of an inexplosive RDX simulant suited to a wide range of measurement methods, including NQR. Measurements are presented that confirm an RDX NQR response from the simulant. The potential use of the simulant for field testing a prototype handheld NQR-based RDX detector is analyzed. Only modest changes in prototype operation during field testing would be required to account for the use of simulant rather than real explosive. PMID:23204647

  12. NQR studies on 2,5-dichlorophenol

    NASA Astrophysics Data System (ADS)

    Kasturi, Alapati; Venkatacharyulu, P.; Premaswarup, D.

    1990-11-01

    Nuclear quadrupole resonance (NQR) Zeeman effect studies were carried out on cylindrical single crystals of 2,5-dichlorophenol, using the two 35Cl-NQR frequencies. A self-quenched superregenerative NQR spectrometer was used, and the spectra were analysed ot obtain information on the nature of the crystalline unit cell. An analysis of the experimental data reveals that: (1) the results are in good agreement with the structural reports of Bavoux and Perrin; (2) the crystal unequivocally belongs to the monoclinic system; (3) there are two crystallographically equivalent but physically inequivalent directions for the principal field gradient axes for both the low- and high-frequency resonance lines; (4) as the number of physically inequivalent directions for each of the two resonance lines is two, the minimum number of molecules per unit cell is two; (5) the b axis (90°,90°) is identified as the symmetry axis; (6) the growth axis is slightly inclined to the c axis; (7) the asymmetry parameters obtained for the loci corresponding to the low-frequency line, which is hydrogen bonded, are greater than those for the high-frequency line, which is nonhydrogen bonded; (8) the double-bond character is greater for the hydrogen-bonded chlorine than for the non-hydrogen-bonded chlorine; (9) the ratios of the various bond characters estimated for both the low- and high-frequency resonance lines are 69:24:7 and 74:24:2.

  13. Nuclear magnetic resonance experiments with dc SQUID amplifiers

    SciTech Connect

    Heaney, M.B. . Dept. of Physics Lawrence Berkeley Lab., CA )

    1990-11-01

    The development and fabrication of dc SQUIDs (Superconducting QUantum Interference Devices) with Nb/Al{sub 2}O{sub 3}/Nb Josephson junctions is described. A theory of the dc SQUID as a radio-frequency amplifier is presented, with an optimization strategy that accounts for the loading and noise contributions of the postamplifier and maximizes the signal-to-noise ratio of the total system. The high sensitivity of the dc SQUID is extended to high field NMR. A dc SQUID is used as a tuned radio-frequency amplifier to detect pulsed nuclear magnetic resonance at 32 MHz from a metal film in a 3.5 Tesla static field. A total system noise temperature of 11 K has been achieved, at a bath temperature of 4.2 K. The minimum number of nuclear Bohr magnetons observable from a free precession signal after a single pulse is about 2 {times} 10{sup 17} in a bandwidth of 25 kHz. In a separate experiment, a dc SQUID is used as a rf amplifier in a NQR experiment to observe a new resonance response mechanism. The net electric polarization of a NaClO{sub 3} crystal due to the precessing electric quadrupole moments of the Cl nuclei is detected at 30 MHz. The sensitivity of NMR and NQR spectrometers using dc SQUID amplifiers is compared to the sensitivity of spectrometers using conventional rf amplifiers. A SQUID-based spectrometer has a voltage sensitivity which is comparable to the best achieved by a FET-based spectrometer, at these temperatures and operating frequencies.

  14. 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.

  15. Microstrip resonators for electron paramagnetic resonance experiments.

    PubMed

    Torrezan, A C; Mayer Alegre, T P; Medeiros-Ribeiro, G

    2009-07-01

    In this article we evaluate the performance of an electron paramagnetic resonance (EPR) setup using a microstrip resonator (MR). The design and characterization of the resonator are described and parameters of importance to EPR and spin manipulation are examined, including cavity quality factor, filling factor, and microwave magnetic field in the sample region. Simulated microwave electric and magnetic field distributions in the resonator are also presented and compared with qualitative measurements of the field distribution obtained by a perturbation technique. Based on EPR experiments carried out with a standard marker at room temperature and a MR resonating at 8.17 GHz, the minimum detectable number of spins was found to be 5 x 10(10) spins/GHz(1/2) despite the low MR unloaded quality factor Q0=60. The functionality of the EPR setup was further evaluated at low temperature, where the spin resonance of Cr dopants present in a GaAs wafer was detected at 2.3 K. The design and characterization of a more versatile MR targeting an improved EPR sensitivity and featuring an integrated biasing circuit for the study of samples that require an electrical contact are also discussed. PMID:19655985

  16. 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.

  17. Polymorphism and disorder in natural active ingredients. Low and high-temperature phases of anhydrous caffeine: Spectroscopic ((1)H-(14)N NMR-NQR/(14)N NQR) and solid-state computational modelling (DFT/QTAIM/RDS) study.

    PubMed

    Seliger, Janez; Žagar, Veselko; Apih, Tomaž; Gregorovič, Alan; Latosińska, Magdalena; Olejniczak, Grzegorz Andrzej; Latosińska, Jolanta Natalia

    2016-03-31

    The polymorphism of anhydrous caffeine (1,3,7-trimethylxanthine; 1,3,7-trimethyl-1H-purine-2,6-(3H,7H)-dione) has been studied by (1)H-(14)N NMR-NQR (Nuclear Magnetic Resonance-Nuclear Quadrupole Resonance) double resonance and pure (14)N NQR (Nuclear Quadrupole Resonance) followed by computational modelling (Density Functional Theory, supplemented Quantum Theory of Atoms in Molecules with Reduced Density Gradient) in solid state. For two stable (phase II, form β) and metastable (phase I, form α) polymorphs the complete NQR spectra consisting of 12 lines were recorded. The assignment of signals detected in experiment to particular nitrogen sites was verified with the help of DFT. The shifts of the NQR frequencies, quadrupole coupling constants and asymmetry parameters at each nitrogen site due to polymorphic transition were evaluated. The strongest shifts were observed at N(3) site, while the smallest at N(9) site. The commercial pharmaceutical sample was found to contain approximately 20-25% of phase I and 75-80% of phase II. The orientational disorder in phase II with a local molecular arrangement mimics that in phase I. Substantial differences in the intermolecular interaction phases I and II of caffeine were analysed using computational (DFT/QTAIM/RDS) approach. The analysis of local environment of each nitrogen nucleus permitted drawing some conclusions on the topology of interactions in both polymorphs. For the most stable orientations in phase I and phase II the maps of the principal component qz of EFG tensor and its asymmetry parameter at each point of the molecular system were calculated and visualized. The relevant maps calculated for both phases I and II indicates small variation in electrostatic potential upon phase change. Small differences between packings in phases slightly disturb the neighbourhood of the N(1) and N(7) nitrogens, thus are meaningless from the biological point of view. The composition of two phases in pharmaceutical material should not be any obstacle, which is relevant from the pharmaceutical industry point of view. PMID:26826282

  18. 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.

  19. The NQR and NMR studies of icosahedral borides

    NASA Astrophysics Data System (ADS)

    Lee, Donghoon; Bray, Philip J.; Aselage, Terry L.

    1999-06-01

    Boron NMR and NQR studies have been performed on three icosahedral borides: icons/Journals/Common/alpha" ALT="alpha" ALIGN="TOP"/>- and icons/Journals/Common/beta" ALT="beta" ALIGN="TOP"/>-rhombohedral boron and boron carbide (B12C3). Two 11B NMR peaks, separated by significant chemical shifts in the range from 130 ppm to 280 ppm, were clearly observed for all of the icosahedral borides that were not enriched in the 10B isotope. A single peak, however, was found for the 10B enriched boron carbide powder (90.6 at.% enrichment.) Moreover, the peak separation in the 11B NMR spectrum for the unenriched icons/Journals/Common/beta" ALT="beta" ALIGN="TOP"/>-boron was reduced when the sample was crushed into a fine powder. In addition to NMR responses, four strong NQR responses were observed for boron carbides from different manufacturers. Two resonance signals, observed at 513 kHz and 2769 kHz, correspond to one of the icosahedral boron sites and the boron in the CBC chain, respectively. The other two NQR responses, having frequencies of 361 and 380 kHz, are either 10B responses for the chain site or 11B responses for the other boron sites in the icosahedra. The NQR responses are not only consistent with the previous NMR studies performed independently by Silver and Bray (1959 J. Chem. Phys. 31 247) and by Hynes and Alexander (1971 J. Chem. Phys. 54 5296, 1972 J. Chem. Phys. Erratum 56), but also provide much higher accuracy for the values of the quadrupolar parameters.

  20. Finite-size effects on the incommensurate phase transition of bis(4-chlorophenyl)sulphone studied by 35Cl NQR

    NASA Astrophysics Data System (ADS)

    Schneider, J.; Schürrer, C.; Brunetti, A.

    1996-08-01

    The temperature behavior of the 35Cl nuclear quadrupolar resonance (NQR) spectrum of thin bis(4-chlorophenyl)sulphone films grown on fine powder samples of TiO2 was studied. In order to characterize the structural and dynamical changes, a comparative study of the NQR parameters of the film with respect to the bulk samples was performed in the temperature range 80-370 K. A shift of the incommensurate phase-transition temperature from 150 in bulk to 156 K in film was detected. Also, the observed NQR spectra in the incommensurate phase suggest qualitative changes in the modulation. The presence of a central intense peak below the transition temperature indicates important contributions to the NQR spectra from periodic domains in the film.

  1. FPGA based pulsed NQR spectrometer

    NASA Astrophysics Data System (ADS)

    Hemnani, Preeti; Rajarajan, A. K.; Joshi, Gopal; Motiwala, Paresh D.; Ravindranath, S. V. G.

    2014-04-01

    An NQR spectrometer for the frequency range of 1 MHz to 5 MHZ has been designed constructed and tested using an FPGA module. Consisting of four modules viz. Transmitter, Probe, Receiver and computer controlled (FPGA & Software) module containing frequency synthesizer, pulse programmer, mixer, detection and display, the instrument is capable of exciting nuclei with a power of 200W and can detect signal of a few microvolts in strength. 14N signal from NaNO2 has been observed with the expected signal strength.

  2. LETTER TO THE EDITOR: ? NQR study of bis(4-chlorophenyl)sulphoxide

    NASA Astrophysics Data System (ADS)

    Osán, T.; Schürrer, C.; Schneider, J.; Brunetti, A.

    1996-08-01

    A pulsed 0953-8984/8/35/002/img2 nuclear quadrupolar resonance (NQR) study was performed on bis(4-chlorophenyl)sulphoxide. In order to characterize the structural thermal behaviour, the NQR spectra were recorded from 80 to 350 K. The results suggest the coexistence of two crystalline phases over the whole scanned temperature range. In spite of the very close molecular structure of the compound with the bis(4-chlorophenyl)sulphone, there is no evidence of any incommensurate phase transition. This fact demonstrates the fundamental role of the molecular group linking phenyl rings in the appearance of a normal - incommensurate phase transition in biphenyl-type compounds.

  3. Temperature dependence of 35Cl NQR in 3,4-Dichlorophenol

    NASA Astrophysics Data System (ADS)

    Chandramani, R.; Devaraj, N.; Indumathy, A.; Ramakrishna, J.

    NQR frequencies in 3,4-dichlorophenol are investigated in the temperature range 77 K to room temperature. Two resonances have been observed throughout the temperature range, corresponding to the two chemically inequivalent chlorine sites. Using Bayer's theory and Brown's method torsional frequencies and their temperature dependence in this range are estimated.

  4. Nuclear Quadrupole Resonance Study of the Nitrogen Mustards and Local Anesthetics.

    NASA Astrophysics Data System (ADS)

    Buess, Michael Lee

    The density matrix description of pulsed nitrogen -14 nuclear quadrupole resonance (NQR) spin-echoes is presented. The parallel between this problem, when formulated in terms of the fictitious spin- 1/2 operators, and that of spin - 1/2 NMR spin-echoes in liquids is discussed along with the complications which arise in multiple-pulse NQR experiments in powders due to the random orientation of the electric field gradient tensors. The equipment and procedures involved in searching for, detecting and identifying NQR resonances using pulsed techniques are described. The ('14)N NQR spectra of several nitrogen mustard compounds in the solid state are reported and analyzed in the framework of the Townes and Dailey theory. For the aniline derivatives, a correlation exists between l -(sigma), l being the nitrogen lone-pair electron density and (sigma) the average N-C sigma bond electron density, and the enhanced Hammett sigma constant (sigma)('-). An improved correlation is obtained between l-(sigma) and (sigma)(,R)('-), which emphasizes the importance of resonance effects in determining l-(sigma). The increase of hydrolysis and alkylation rates with increasing values of l-(sigma) is in agreement with the identification of the cyclic immonium ion as the intermediate in the hydrolysis and alkylation processes of the aromatic nitrogen mustards. A possible correlation is noted between the ('35)Cl NQR spectra for some of the mustards and measures of toxic and antitumor activity. ('14)N NQR spectra for several local anesthetics in the solid state are also reported and analyzed using the Townes and Dailey approach. The changes in the electron distributions at various nitrogen sites, produced by protonating the tertiary amino nitrogen, are discussed and shown to be in general agreement with expectations bases on the increased electrophilic character of the protonated amino group.

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

    PubMed

    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 (14)N 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 (14)N 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 (14)N NQR based detection device. PMID:25233110

  6. 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.

  7. Antiferromagnetic properties of a water-vapor-inserted YBa2 Cu3 O6.5 compound studied byNMR, NQR, and μSR

    NASA Astrophysics Data System (ADS)

    Dooglav, A. V.; Egorov, A. V.; Mukhamedshin, I. R.; Savinkov, A. V.; Alloul, H.; Bobroff, J.; Macfarlane, W. A.; Mendels, P.; Collin, G.; Blanchard, N.; Picard, P. G.; King, P. J. C.; Lord, J.

    2004-08-01

    We present a detailed NQR, nuclear magnetic resonance (NMR), and μSR study of the magnetic phase obtained during a topotactic chemical reaction of YBa2Cu3O6.5 high-temperature superconductor with low-pressure water vapor. Cu65 -enriched samples have been used for NQR/NMR studies which allows to get a good resolution in the Cu(1) NQR and Cu(2) zero field NMR (ZFNMR) spectra. It is shown that the NQR spectrum of the starting material transforms progressively under insertion of water, and almost completely disappears when about one H2O molecule is inserted per unit cell. Similarly, a Cu65 ZFNMR signal characteristic of this water inserted material appears and grows with increasing water content, which indicates that the products of the reaction are nonsuperconducting antiferromagnetic phases in which the copper electronic magnetic moments in the CuO2 bilayers are ordered. The use of Cu65 -enriched samples allowed us to reliably resolve three different copper resonances which correspond to different internal magnetic fields. The antiferromagnetic phases are also felt by proton NMR which reveals two sites with static internal fields of 150 and about 15 Gauss, respectively. μSR studies performed on a series of samples prepared in the same way as the C65u -enriched ones reveal two muon sites with the same local fields as the proton sites, which vanish at T≈400K . This indicates that muons preferentially occupy proton vacancy sites, and that the magnetic phases have similar Néel temperatures as the other bilayer undoped cuprate compounds. An analysis of the internal fields on the different spin probes suggests that they can be all assigned to a single magnetic phase at large water content in which the Cu(1) electron spins order with those of the Cu(2) . The detailed evolution of the spectra with the progressive increase of water content is shown to be compatible with a coexistence of phases during the early stages ot the reaction. It appears that even samples packed in paraffin underwent a transformation of a substantial part of the sample after 6 years storage in atmosphere. Samples packed in Stycast epoxy resin heated moderately to a temperature (200°C) undergo a reaction with epoxy decomposition products which yield the formation of the same final compound. It is clear that such effects should be considered quite seriously and avoided in experiments attempting to resolve tiny effects in these materials, such as those performed in some recent neutron scattering experiments.

  8. Dielectric square resonator investigated with microwave experiments.

    PubMed

    Bittner, S; Bogomolny, E; Dietz, B; Miski-Oglu, M; Richter, A

    2014-11-01

    We present a detailed experimental study of the symmetry properties and the momentum space representation of the field distributions of a dielectric square resonator as well as the comparison with a semiclassical model. The experiments have been performed with a flat ceramic microwave resonator. Both the resonance spectra and the field distributions were measured. The momentum space representations of the latter evidenced that the resonant states are each related to a specific classical torus, leading to the regular structure of the spectrum. Furthermore, they allow for a precise determination of the refractive index. Measurements with different arrangements of the emitting and the receiving antennas were performed and their influence on the symmetry properties of the field distributions was investigated in detail, showing that resonances with specific symmetries can be selected purposefully. In addition, the length spectrum deduced from the measured resonance spectra and the trace formula for the dielectric square resonator are discussed in the framework of the semiclassical model. PMID:25493860

  9. Dielectric square resonator investigated with microwave experiments

    NASA Astrophysics Data System (ADS)

    Bittner, S.; Bogomolny, E.; Dietz, B.; Miski-Oglu, M.; Richter, A.

    2014-11-01

    We present a detailed experimental study of the symmetry properties and the momentum space representation of the field distributions of a dielectric square resonator as well as the comparison with a semiclassical model. The experiments have been performed with a flat ceramic microwave resonator. Both the resonance spectra and the field distributions were measured. The momentum space representations of the latter evidenced that the resonant states are each related to a specific classical torus, leading to the regular structure of the spectrum. Furthermore, they allow for a precise determination of the refractive index. Measurements with different arrangements of the emitting and the receiving antennas were performed and their influence on the symmetry properties of the field distributions was investigated in detail, showing that resonances with specific symmetries can be selected purposefully. In addition, the length spectrum deduced from the measured resonance spectra and the trace formula for the dielectric square resonator are discussed in the framework of the semiclassical model.

  10. Radiative widths of resonances (experiments)

    SciTech Connect

    Gidal, G.

    1988-07-01

    After a hiatus of several years, this conference brings us considerable new data on resonance production in photon photon interactions. I will first discuss the contributions concerning the tensor, pseudoscalar and scalar mesons, then review the current status of the (c/ovr string/c /eta//sub c/) and finally summarize the exciting new results concerning the spin 1 mesons. 40 refs., 21 figs., 7 tabs.

  11. 75As-NQR study of the hybridization gap semiconductor CeOs4As12

    NASA Astrophysics Data System (ADS)

    Yogi, M.; Higa, N.; Niki, H.; Kawata, T.; Sekine, C.

    2016-02-01

    We performed an 75As nuclear quadrupole resonance (NQR) measurement on CeOs4As12. The 75As-NQR spectrum shape demonstrates that the Ce-site filling fraction of our high-pressure synthesized sample is close to unity. A presence of the c — f hybridization gap is confirmed from the temperature dependence of the nuclear spin-lattice relaxation rate 1/T1. An increase of 1/T1 below ∼3 K indicates a development of the spin fluctuations. The 1/T1 for CeOs4As12 shows similar behavior as that for CeOs4Sb12 with different magnitude of the c — f hybridization gap. An absence of phase transition in CeOs4As12 may be caused by the increase of the c — f hybridization, which increases the gap magnitude and reduces the residual density of state inside the gap.

  12. Student Experiments on Parametric Resonance.

    ERIC Educational Resources Information Center

    Falk, Lars

    1979-01-01

    Describes some experiments of parametric effects intended to be disigned by the students themselves and shows how to introduce parametric interactions and nonlinearities to the students in a simple manner. (GA)

  13. 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 νQ ≊ 1.8MHz and asymmetry parameter η ≊ 0 [Kubo T et al 2014 JPS Conf. Proc. 3 012031]. From 27Al-NMR/NQR, NQR parameters are obtained to be νQ,A ≊ 1.53 MHz, and ηA ≊ 0.20 for the site A, and νQ,B ≊ 2.28 MHz, and ηB ≊ 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.

  14. 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)

    Latosińska, J. N.; Latosińska, 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.

  15. Undergraduate Electron-Spin-Resonance Experiment.

    ERIC Educational Resources Information Center

    Willis, James S.

    1980-01-01

    Describes the basic procedures for use of an electron-spin resonance spectrometer and potassium azide (KN3) in an experiment which extends from the phase of sample preparation (crystal growth, sample mounting, and orientation) through data taking to the stages of calculation and theoretical explanation. (Author/DS)

  16. Superconducting microwave resonators for physics experiments

    NASA Astrophysics Data System (ADS)

    Klein, N.; Mueller, G.; Piel, H.; Schurr, J.

    1989-03-01

    Superconducting resonators at K-band frequencies have been developed for different applications in general physics. Niobium pillbox cavities have been built for the one-atom maser experiment by which the interaction of Rydberg atoms with single microwave photons has been investigated. At 21.5 GHz and 1.3 K, quality factors of up to 10 to the 11th were obtained. Coating of the cavity with Nb3Sn resulted in quality factors of 6 x 108 at 4.2 K and 6 x 10 9th at 2 K. A superconducting Fabry-Perot resonator consisting of two spherically curved niobium mirrors was also investigated. The quality factor of 1.8 x 10 to the 7th measured at 25 GHz and 4.2 K was found to be two orders of magnitude higher than for a corresponding copper resonator. Fabry-Perot resonators can be used for detecting small position changes for one mirror with respect to another caused by gravitational forces. First experiments with copper Fabry-Perot mirrors suspended in a vacuum chamber provided a maximum sensitivity for a gravitational acceleration of one mirror of 4 x 10 to the -11th m/sec sq. These results are promising for a possible fifth force detector based on a superconducting Fabry-Perot resonator.

  17. NQR in Alanine and Lysine Iodates

    NASA Astrophysics Data System (ADS)

    Petrosyan, A. M.; Burbelo, V. M.; Tamazyan, R. A.; Karapetyan, H. A.; Sukiasyan, R. P.

    2000-02-01

    The structure o f iodates of α- and β-alanine ( Ala) (2(β-Ala • HIO3) • H2O , β-Ala-2HIO3 , D L-Ala• HIO3 • 2H2O, L-Ala • HIO3) and L-lysine (L-Lys) (L-Lys • HIO3, L-Lys • 2HIO3,L-Lys • 3HIO3, L-Lys • 6HIO3) have been investigated by means of iodine-127 NQR, IR spectroscopy and X-ray diffraction

  18. 35Cl-NQR and DFT study of electronic structure of amlodipine and felodipine vascular-selective drugs from the dihydropyridine Ca ++ antagonists group

    NASA Astrophysics Data System (ADS)

    Latosińska, J. N.; Latosińska, M.; Kasprzak, J.

    2008-09-01

    Amlodipine (AM) and felodipine (FL) have been studied in solid state by the nuclear quadrupole resonance (NQR) and density functional theory (DFT). The results have shown that NQR data do not permit a differentiation between R and S enantiomers, which is a consequence of the symmetry of the 4-aryl ring, whereas they permit a differentiation between free bases and salts. The HOMO-LUMO gap is smaller for AM than for FL, which suggests smaller energy of excitation for AM. The absolute hardness, chemical potential and electrophilicity of both AM enantiomers are lower than the corresponding values for FL enantiomers, suggesting that AM should be more reactive than FL in unimolecular reactions.

  19. Radio-frequency tunable atomic magnetometer for detection of solid-state NQR

    NASA Astrophysics Data System (ADS)

    Lee, S.-K.; Sauer, K. L.; Seltzer, S. J.; Alem, O.; Romalis, M. V.

    2007-06-01

    We constructed a potassium atomic magnetometer which resonantly detects rf magnetic fields with subfemtotesla sensitivity. The resonance frequency is set by the Zeeman resonance of the potassium atoms in a static magnetic field applied to the magnetometer cell. Strong optical pumping of the potassium atoms into a stretched state reduces spin-exchange broadening of the Zeeman resonance, resulting in relatively small linewidth of about 200 Hz (half-width at half-maximum). The magnetometer was used to detect ^14N NQR signal from powdered ammonium nitrate at 423 kHz, with sensitivity an order of magnitude higher than with a conventional room temperature pickup coil with comparable geometry. The demonstrated sensitivity of 0.24 fT/Hz^1/2 can be improved by several means, including use of higher power lasers for pumping and probing. Our technique can potentially be used to develop a mobile, open-access NQR spectrometer for detection of nitrogen-containing solids of interest in security applications.

  20. Resonance Structure with Polarization Experiments at MAMI

    SciTech Connect

    Arends, Hans-Juergen

    2011-10-21

    The Mainz Microtron MAMI is an ideal facility to study the hadron structure with the electromagnetic probe. With the new accelerator stage, the Harmonic Double-Sided Microtron (HDSM), which is in operation since 2007, high-intensity polarized electron and photon beams with energies up to 1.6 GeV are delivered to the experiments. Polarized proton, deuteron, {sup 3}He targets, and recoil proton polarimeters are available to allow a broad range of polarization observables for low-mass nucleon resonances to be measured. In this talk, an overview over selected recent double polarization experiments at MAMI is given.

  1. NQR Relaxation Studies on Halogenomethyl Groups in Halogenoacetates

    NASA Astrophysics Data System (ADS)

    Zdanowska-Fnjczek, Maria

    1998-07-01

    The effect of temperature on the chlorine NQR spin-lattice relaxation times in CsH(ClH2-CCOO)2 , KH(Cl3 CCOO) 2 and N(CH3)4 H(ClF2CCOO)2 has been studied in the temperature range 77 K to room temperature. The results were discussed on the basis of NQR relaxation theory.

  2. Beta-detected NQR in zero field with a low energy beam of 8Li+

    NASA Astrophysics Data System (ADS)

    Salman, Z.; Kiefl, R. F.; Chow, K. H.; MacFarlane, W. A.; Kreitzman, S. R.; Arseneau, D. J.; Daviel, S.; Levy, C. D. P.; Maeno, Y.; Poutissou, R.

    2006-03-01

    Beta-detected nuclear quadrupole resonances ( β-NQR) in zero field are observed using a beam of low energy highly polarized radioactive Li+8. The resonances were detected in SrTiO 3, Al 2O 3 and Sr 2RuO 4 single crystals by monitoring the beta-decay anisotropy as a function of a small audio frequency magnetic field. The resonances show clearly that Li+8 occupies one site with non-cubic symmetry in SrTiO 3, two in Al 2O 3 and three sites in Sr 2RuO 4. The resonance amplitude and width are surprisingly large compared to the values expected from transitions between the |±2>↔|±1> spin states, indicating a significant mixing between the |±m> quadrupolar split levels.

  3. New perspectives in the PAW/GIPAW approach: J(P-O-Si) coupling constants, antisymmetric parts of shift tensors and NQR predictions.

    PubMed

    Bonhomme, Christian; Gervais, Christel; Coelho, Cristina; Pourpoint, Frédérique; Azaïs, Thierry; Bonhomme-Coury, Laure; Babonneau, Florence; Jacob, Guy; Ferrari, Maude; Canet, Daniel; Yates, Jonathan R; Pickard, Chris J; Joyce, Siân A; Mauri, Francesco; Massiot, Dominique

    2010-12-01

    In 2001, Pickard and Mauri implemented the gauge including projected augmented wave (GIPAW) protocol for first-principles calculations of NMR parameters using periodic boundary conditions (chemical shift anisotropy and electric field gradient tensors). In this paper, three potentially interesting perspectives in connection with PAW/GIPAW in solid-state NMR and pure nuclear quadrupole resonance (NQR) are presented: (i) the calculation of J coupling tensors in inorganic solids; (ii) the calculation of the antisymmetric part of chemical shift tensors and (iii) the prediction of (14)N and (35)Cl pure NQR resonances including dynamics. We believe that these topics should open new insights in the combination of GIPAW, NMR/NQR crystallography, temperature effects and dynamics. Points (i), (ii) and (iii) will be illustrated by selected examples: (i) chemical shift tensors and heteronuclear (2)J(P-O-Si) coupling constants in the case of silicophosphates and calcium phosphates [Si(5)O(PO(4))(6), SiP(2)O(7) polymorphs and α-Ca(PO(3))(2)]; (ii) antisymmetric chemical shift tensors in cyclopropene derivatives, C(3)X(4) (X = H, Cl, F) and (iii) (14)N and (35)Cl NQR predictions in the case of RDX (C(3)H(6)N(6)O(6)), β-HMX (C(4)H(8)N(8)O(8)), α-NTO (C(2)H(2)N(4)O(3)) and AlOPCl(6). RDX, β-HMX and α-NTO are explosive compounds. PMID:20589728

  4. Two-dimensional exchange 35Cl NQR spectroscopy of hexachloroethane

    NASA Astrophysics Data System (ADS)

    Maćkowiak, Mariusz; Sinyavsky, Nicolay; Bluemich, Bernhard

    2005-05-01

    Two-dimensional exchange 35Cl NQR spectroscopy for studies of the CCl 3-group reorientation processes in hexachloroethane has been applied. It has been demonstrated that 2D NQR exchange spectroscopy is appropriate for quantitative studies of exchange processes in molecular crystals containing quadrupole nuclei. The method is of particular value for the detection of exchange networks in systems with many sites. Thus, detailed information on the exchange pathways within a network of structural isomers in hexachloroethane can be deduced and a proper assignment of the NQR lines can be made. Temperature dependence of the exchange rate was studied. The mixing dynamics by exchange and the expected cross-peak intensities have been derived. The very good agreement of the experimental results with theoretical predictions confirms the validity of the motion model.

  5. Specific Heat and Nuclear Quadrupole Resonance Study of Thiourea-Hexachloroethane Inclusion Compound

    NASA Astrophysics Data System (ADS)

    Chekhova, G. N.; Goren, S. D.; Krieger, Ju. H.; Linsky, D.; Lusternik, V.; Panich, A. M.; Semenov, A. R.; Voronel, A.

    2000-02-01

    Specific heat and 35Cl nuclear quadrupole resonance (NQR) measurements of the channel thio-urea-hexachloroethane inclusion compound are presented. Experimental NQR data confirm the results of atom-atom potential calculations that the guest sublattice comprises two types of nearly commensurate finite molecular chains, having different structure and separated by domain walls. Specific heat measurements show phase transition near 96 K.

  6. 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.

  7. Single crystal zeeman effect studies on 35Cl NQR lines of 2,6-dichlorophenol

    NASA Astrophysics Data System (ADS)

    Prasad, N. V. L. N.; Venkatacharyulu, P.; Premaswarup, D.

    1987-10-01

    Zeeman effect studies on the two 35Cl NQR lines in cylindrical single crystals of 2,6-dichlorophenol were carried out using a self-quenched super-regenerative NQR spectrometer to obtain information on the nature of the crystalline unit cell and the effect of hydrogen bonding on the electric field gradient tensor. Analysis of the experimental data reveals: (1) the results are in good agreement with those reported from X-ray studies; (2) the crystal is unequivocally identified as belonging to the orthorhombic system; (3) there are two crystallographically equivalent and four physically nonequivalent directions for the principal field gradients for both the low and high frequency resonance lines; (4) the directions of the crystalline a, b, c axes are uniquely identified as (90°, 0°), (0°, -), and (90°, 90°); (5) the b-axis is identified as the growth axis; (6) there are a minimum of four molecules per unit cell, the four molecules lie in different planes, which are, however, connected by symmetry operations; (7)_there exists a weak intramolecular hydrogen bonding in the crystal; (8) the asymmetry parameters for the loci corresponding to the low frequency resonance line, which is affected by hydrogen bonding, are less than the asymmetry parameters of the loci corresponding to the high frequency resonance line, which is not affected by hydrogen bonding; (9) the single bond and ionic bond characters for the hish frequency line are less than that of the low frequency line, while the double bond character for the low frequency line is less than that of the high frequency line and (10) the small deviation between the single bond and double bond characters of the two resonance lines is attributed to the existence of weak hydrogen bonding in the crystal.

  8. Volovik effect and Fermi-liquid behavior in the s -wave superconductor CaPd2As2: 75As NMR-NQR measurements

    NASA Astrophysics Data System (ADS)

    Ding, Q.-P.; Wiecki, P.; Anand, V. K.; Sangeetha, N. S.; Lee, Y.; Johnston, D. C.; Furukawa, Y.

    2016-04-01

    The electronic and magnetic properties of the collapsed-tetragonal CaPd2As2 superconductor (SC) with a transition temperature of 1.27 K have been investigated by 75As nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements. The temperature (T ) dependence of the nuclear spin lattice relaxation rates (1 /T1) and the Knight shifts indicate the absence of magnetic correlations in the normal state. In the SC state, 1 /T1 measured by 75As NQR shows a clear Hebel-Slichter (HS) peak just below Tc and decreases exponentially at lower T , confirming a conventional s -wave SC. In addition, the Volovik effect, also known as the Doppler shift effect, has been clearly evidenced by the observation of the suppression of the HS peak with applied magnetic field.

  9. Volovik effect and Fermi-liquid behavior in the s-wave superconductor CaPd2As2: As75 NMR-NQR measurements

    DOE PAGESBeta

    Ding, Q. -P.; Wiecki, P.; Anand, V. K.; Sangeetha, N. S.; Lee, Y.; Johnston, D. C.; Furukawa, Y.

    2016-04-07

    The electronic and magnetic properties of the collapsed-tetragonal CaPd2As2 superconductor (SC) with a transition temperature of 1.27 K have been investigated by 75As nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements. The temperature (T) dependence of the nuclear spin lattice relaxation rates (1/T1) and the Knight shifts indicate the absence of magnetic correlations in the normal state. In the SC state, 1/T1 measured by 75As NQR shows a clear Hebel-Slichter (HS) peak just below Tc and decreases exponentially at lower T, confirming a conventional s-wave SC. Additionally, the Volovik effect, also known as the Doppler shift effect, hasmore » been clearly evidenced by the observation of the suppression of the HS peak with applied magnetic field.« less

  10. 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 ( νQ) 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.

  11. 35Cl NQR and Structural Studies of Chloroacetanilides C6H3Cl2NHCOCH3-xClx, 1 ≤ x ≤ 3

    NASA Astrophysics Data System (ADS)

    Groke, Dirk; Dou, Shi-Qi; Weiss, Alarich

    1992-02-01

    The temperature dependence of 35Cl NQR frequencies and the phase transition behaviour of chloroacetanilides (N-[2,6-dichlorophenyl]-2-chloroacetamide, -2,2-dichloroacetamide, -2,2,2-trichloroacetamide) were investigated. The crystal structure determination of N-[2,6-dichlorophenyl]- 2-chloroacetamide leads to the following: a = 1893.8 pm, b = 1110.7 pm, c = 472.1 pm, space group P212121 = D24 with Z = 4 molecules per unit cell. The arrangement of the molecules and their geometry is comparable to the high temperature phase of the acetyl compound N-[2,6-dichlorophenyl]- acetamide. For N-[2,6-diclorophenyl]-2,2,2-trichloroacetamide it was found: a = 1016.6 pm, b = 1194.3 pm, c = 1006.7 pm, ß= 101.79°, space group P21/c = C52h, Z = 4. The structure is similar to the low temperature phase of N-[2,6-dichlorophenyl]-acetamide. Parallelism between the temperature dependence of the 35C1 NQR lines of the CCl3 group and the X-ray diffraction results concerning the different behaviour of the chlorine atoms was observed. The structures of the compounds show intermolecular hydrogen bonding of the N - H • • • O - C type. The phenyl group and the HNCO function are nearly planar. A bleaching out of several 35Cl NQR lines at a temperature far below the melting point of the substances was observed. The different types of chlorine atoms (aromatic, chloromethyl) can be distinguished by their temperature coefficients of the 35Cl NQR frequencies. All the resonances found show normal "Bayer" temperature behaviour. N-[2,6-dichlorophenyl]-2,2-diehloroacetamide shows several solid phases. One stable low temperature phase and an instable high temperature phase (at room temperature) were observed. The different phases were detected by means of 35Cl NQR spectroscopy and thermal analysis

  12. Rapid Measurement of Nutation NQR Spectra in Powders Using an RF Pulse Train

    NASA Astrophysics Data System (ADS)

    Sinyavsky, Nicolai; Ostafin, Michał; Maćkowiak, Mariusz

    1996-06-01

    The method of two-dimensional nutation NQR spectroscopy, introduced by Harbison in 1989, has been successfully used for determining of the asymmetry parameter of the EFG tensor for spin-3/2 nuclei in both powdered and monocrystal samples in the absence of an external magnetic field. The inconvenience inherent in the method, however, is the long time required, because data acquisition must be repeated for various RF pulse lengths. We discuss a method to reduce the time of the nutation experiment by using a sequence of identical short RF pulses of length r w and distance τ. It is shown that for an NQR frequency ω0 , frequency offset Δω, and pulse parameters satisfying the relation ω0τ + Δωtw = 2πk (k = 1, 2, 3,..., n) a synchronism of pulse action takes place and the nutation interferogram can be measured "stroboscopically" between the pulses. The maximum time saving factor that can be obtained as compared to the conventional nutation experiment is of the order of the number of pulses used in a pulse train. The method has been successfully applied for determination of the asymmetry parameter for one of the two 3 5 Cl sites in polycrystalline 2,4,6-trichloro-1,3,5-triazine (cyanuric chloride).

  13. Miniature Magnet for Electron Spin Resonance Experiments

    ERIC Educational Resources Information Center

    Rupp, L. W.; And Others

    1976-01-01

    Describes commercially available permanent magnets that have been incorporated in a compact and inexpensive structure providing both field sweep and modulation suitable for electron spin resonance at microwave frequencies. (MLH)

  14. Local resonance bandgaps in periodic media: theory and experiment.

    PubMed

    Raghavan, L; Phani, A Srikantha

    2013-09-01

    Periodic composites such as acoustic metamaterials use local resonance phenomenon in designing low frequency sub-Bragg bandgaps. These bandgaps emerge from a resonant scattering interaction between a propagating wave and periodically arranged resonators. This paper develops a receptance coupling technique to combine the dynamics of the resonator with the unit cell dynamics of the background medium to analyze flexural wave transmission in a periodic structure, involving a single degree of freedom coupling between the medium and the resonator. Receptance techniques allow for a straightforward extension to higher dimensional systems with multiple degrees of freedom coupling and for easier experimental measurements. Closed-form expressions for the location and width of sub-Bragg bandgaps are obtained. Rigid body modes of the unit cell of the background medium are shown to set the bounding frequencies for local resonance bandgaps. Results from the receptance analysis compare well with Bloch wave analysis and experiments performed on a finite structural beam with periodic masses and resonators. Stronger coupling and inertia of the resonator increase the local resonance bandgap width. Two-fold periodicity widens the Bragg bandgap, narrowed by local resonators, thus expanding the design space and highlighting the advantages of hierarchical periodicity. PMID:23967928

  15. 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.

  16. Nuclear magnetic resonance with dc SQUID preamplifiers

    SciTech Connect

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

    1989-03-01

    Sensitive radio-frequency (rf) amplifiers based on dc Superconducting QUantum Intererference Devices (SQUIDSs) 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 x 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.

  17. Chlorine-35 NQR and 1H NMR study of guest structure and dynamics in the thiourea-hexachloroethane inclusion compound

    NASA Astrophysics Data System (ADS)

    Panich, A. M.; Krieger, Ju H.; Semenov, A. R.; Goren, S. D.; Chekhova, G. N.

    2000-07-01

    Atom-atomic potential calculation of the channel non-stoichiometric thiourea-hexachloroethane inclusion compound shows that the structure of the guest sublattice comprises two types of finite molecular chain, having different structure and separated by domain walls. In the present paper we present results of 35Cl NQR and 1H NMR measurements of thiourea-hexachloroethane, [2.95(NH2)2CS]C2Cl6, in the temperature range from 7.5 to 90 K, which confirm this model and show the existence of such a state at least below 60 K. Two resonances in the NQR spectra were assigned to the two nearly commensurate regions, while the third resonance, showing an anomalous behaviour, was attributed to the guest molecules in the domain wall. The observed structure results from the different periodicity of the guest and host substructures and shows a difference from conventional continuum models of the incommensurate state. Propagation motion of the domain wall over the channel is discussed.

  18. Chemical structure and intra-molecular effects on NMR-NQR tensors of harmine and harmaline alkaloids

    NASA Astrophysics Data System (ADS)

    Ahmadinejad, Neda; Tahan, Arezoo; Talebi Tari, Mostafa

    2016-02-01

    Density functional theory (DFT) methods were used to analyze the effects of molecular structure and ring currents on the NMR chemical shielding tensors and NQR frequencies of harmine and harmaline alkaloids in the gas phase. The results demonstrated that NMR tensors and NQR frequencies of 15N nuclei in these compounds depend on chemical environment and resonance interactions. Hence, their values are obviously different in the mentioned structures. The interpretation of natural bond orbital (NBO) data suggests that in harmine structure, the lone pair participation of N9 in π-system electron clouds causes to development of aromaticity nature in pyrrole ring. However, the chemical shielding around N9 atom in harmine structure is higher than in harmaline, while in harmaline structure, lone pair participation of N2 in π-system electron clouds causes to development of aromaticity nature in pyridine ring. Hence, chemical shielding around N2 atom in harmaline structure is higher than in harmine. It can be deduced that by increasing lone pair electrons contribution of nitrogen atoms in ring resonance interactions and aromaticity development, the values of NMR chemical shielding around them increase, while χ and q zz values of these nuclei decrease.

  19. Spatiotemporal Stochastic Resonance:Theory and Experiment

    NASA Astrophysics Data System (ADS)

    Peter, Jung

    1996-03-01

    The amplification of weak periodic signals in bistable or excitable systems via stochastic resonance has been studied intensively over the last years. We are going one step further and ask: Can noise enhance spatiotemporal patterns in excitable media and can this effect be observed in nature? To this end, we are looking at large, two dimensional arrays of coupled excitable elements. Due to the coupling, excitation can propagate through the array in form of nonlinear waves. We observe target waves, rotating spiral waves and other wave forms. If the coupling between the elements is below a critical threshold, any excitational pattern will die out in the absence of noise. Below this threshold, large scale rotating spiral waves - as they are observed above threshold - can be maintained by a proper level of the noise[1]. Furthermore, their geometric features, such as the curvature can be controlled by the homogeneous noise level[2]. If the noise level is too large, break up of spiral waves and collisions with spontaneously nucleated waves yields spiral turbulence. Driving our array with a spatiotemporal pattern, e.g. a rotating spiral wave, we show that for weak coupling the excitational response of the array shows stochastic resonance - an effect we have termed spatiotemporal stochastic resonance. In the last part of the talk I'll make contact with calcium waves, observed in astrocyte cultures and hippocampus slices[3]. A. Cornell-Bell and collaborators[3] have pointed out the role of calcium waves for long-range glial signaling. We demonstrate the similarity of calcium waves with nonlinear waves in noisy excitable media. The noise level in the tissue is characterized by spontaneous activity and can be controlled by applying neuro-transmitter substances[3]. Noise effects in our model are compared with the effect of neuro-transmitters on calcium waves. [1]P. Jung and G. Mayer-Kress, CHAOS 5, 458 (1995). [2]P. Jung and G. Mayer-Kress, Phys. Rev. Lett.62, 2682 (1995). [3] A. Cornell-Bell, Steven M. Finkbeiner, Mark.S. Cooper and Stephen J. Smith, SCIENCE, 247, 373 (1990).

  20. Detecting body cavity bombs with nuclear quadrupole resonance

    NASA Astrophysics Data System (ADS)

    Collins, Michael London

    Nuclear Quadrupole Resonance (NQR) is a technology with great potential for detecting hidden explosives. Past NQR research has studied the detection of land mines and bombs concealed within luggage and packages. This thesis focuses on an NQR application that has received less attention and little or no publicly available research: detecting body cavity bombs (BCBs). BCBs include explosives that have been ingested, inserted into orifices, or surgically implanted. BCBs present a threat to aviation and secure facilities. They are extremely difficult to detect with the technology currently employed at security checkpoints. To evaluate whether or not NQR can be used to detect BCBs, a computational model is developed to assess how the dielectric properties of biological tissue affect the radio frequency magnetic field employed in NQR (0.5-5MHz). The relative permittivity of some biological tissue is very high (over 1,000 at 1MHz), making it conceivable that there is a significant effect on the electromagnetic field. To study this effect, the low-frequency approximation known as the Darwin model is employed. First, the electromagnetic field of a coil is calculated in free space. Second, a dielectric object or set of objects is introduced, and the free-space electric field is modified to accommodate the dielectric object ensuring that the relevant boundary conditions are obeyed. Finally, the magnetic field associated with the corrected electric field is calculated. This corrected magnetic field is evaluated with an NQR simulation to estimate the impact of dielectric tissue on NQR measurements. The effect of dielectric tissue is shown to be small, thus obviating a potential barrier to BCB detection. The NQR model presented may assist those designing excitation and detection coils for NQR. Some general coil design considerations and strategies are discussed.

  1. Hafnium Resonance Parameter Analysis Using Neutron Capture and Transmission Experiments

    SciTech Connect

    Trbovich, M J; Barry, D P; Slovacek, R E; Danon, Y; Block, R C; Francis, N C; Lubert, M; Burke, J A; Drindak, N J; Lienweber, G; Ballad, R

    2007-02-06

    The focus of this work is to determine the resonance parameters for stable hafnium isotopes in the 0.005 - 200 eV region, with special emphasis on the overlapping {sup 176}Hf and {sup 178}Hf resonances near 8 eV. Accurate hafnium cross sections and resonance parameters are needed in order to quantify the effects of hafnium found in zirconium, a metal commonly used in reactors. The accuracy of the cross sections and the corresponding resonance parameters used in current nuclear analysis tools are rapidly becoming the limiting factor in reducing the overall uncertainty on reactor physics calculations. Experiments measuring neutron capture and transmission are routinely performed at the Rensselaer Polytechnic Institute (RPI) LINAC using the time-of flight technique. {sup 6}Li glass scintillation detectors were used for transmission experiments at flight path lengths of 15 and 25 m, respectively. Capture experiments were performed using a sixteen section NaI multiplicity detector at a flight path length of 25 m. These experiments utilized several thicknesses of metallic and isotope-enriched liquid Hf samples. The liquid Hf samples were designed to provide information on the {sup 176}Hf and {sup 178}Hf contributions to the 8 eV doublet without saturation. Data analyses were performed using the R-matrix Bayesian code SAMMY. A combined capture and transmission data analysis yielded resonance parameters for all hafnium isotopes from 0.005 - 200 eV. Additionally, resonance integrals were calculated, along with errors for each hafnium isotope, using the NJOY and INTER codes. The isotopic resonance integrals calculated were significantly different than previous values. The {sup 176}Hf resonance integral, based on this work, is approximately 73% higher than the ENDF/B-VI value. This is due primarily to the changes to resonance parameters in the 8 eV resonance, the neutron width presented in this work is more than twice that of the previous value. The calculated elemental hafnium resonance integral however, changed very little.

  2. 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.

  3. Double resonance with coupled multiplets

    NASA Astrophysics Data System (ADS)

    Brosnan, S. G. P.; Edmonds, D. T.

    Double resonance with coupled multiplets is a very high sensitivity technique for measuring the NQR spectra of nuclei with half integer ( I {1}/{2}) spins. The spectra of naturally abundant (0.037%) 17O are detected with ease. The spectra reveal fine structure which enhances the NQR technique as a probe of electronic structure. The theory of DRCM is given and its application in practice is discussed with examples. The effect of spin-lattice relaxation of the quadrupolar nuclei is described.

  4. NMR and NQR parameters of the SiC-doped on the (4,4) armchair single-walled BPNT: a computational study.

    PubMed

    Baei, Mohammad T; Sayyad-Alangi, S Zahra; Moradi, Ali Varasteh; Torabi, Parviz

    2012-03-01

    The structural properties, NMR and NQR parameters in the pristine and silicon carbide (SiC) doped boron phosphide nanotubes (BPNTs) were calculated using DFT methods (BLYP, B3LYP/6-31G) in order to evaluate the influence of SiC-doped on the (4,4) armchair BPNTs. Nuclear magnetic resonance (NMR) parameters including isotropic (CS(I)) and anisotropic (CS(A)) chemical shielding parameters for the sites of various (13)C, (29)Si, (11)B, and (31)P atoms and quadrupole coupling constant (C ( Q )), and asymmetry parameter (η ( Q )) at the sites of various (11)B nuclei were calculated in pristine and SiC- doped (4,4) armchair boron phosphide nanotubes models. The calculations indicated that doping of (11)B and (31)P atoms by C and Si atoms had a more significant influence on the calculated NMR and NQR parameters than did doping of the B and P atoms by Si and C atoms. In comparison with the pristine model, the SiC- doping in Si(P)C(B) model of the (4,4) armchair BPNTs reduces the energy gaps of the nanotubes and increases their electrical conductance. The NMR results showed that the B and P atoms which are directly bonded to the C atoms in the SiC-doped BPNTs have significant changes in the NMR parameters with respect to the B and P atoms which are directly bonded to the Si atoms in the SiC-doped BPNTs. The NQR results showed that in BPNTs, the B atoms at the edges of nanotubes play dominant roles in determining the electronic behaviors of BPNTs. Also, the NMR and NQR results detect that the Fig. 1b (Si(P)C(B)) model is a more reactive material than the pristine and the Fig. 1a (Si(B)C(p)) models of the (4,4) armchair BPNTs. PMID:21625895

  5. Applications of nuclear quadrupole resonance spectroscopy in drug development.

    PubMed

    Latosinńska, Jolanta N

    2007-02-01

    In this review, fundamentals of nuclear quadrupole resonance (NQR) spectroscopy are briefly outlined. Examples of its applications in drug development are discussed to demonstrate that the NQR method is a sophisticated, non-destructive and valuable analytical technique for studying pharmaceuticals, providing effective assistance at the two main steps of drug development: the physical and chemical characterization of the active pharmaceutical ingredients (API) at the analytical step and API development. This review covers different aspects of the use of NQR spectroscopy for drug development and analysis and illustrates the power and versatility of this method in the determination of impurities, polymorphic forms, the drug's structure and conformation, characterization of the interactions between the drug and ligands, search for analogs (second- or third-generation drugs) and the drug's thermal stability. Lastly, NQR advantages and restrictions in the aspect of application in drug development studies are summarized. PMID:23496079

  6. Ferromagnetic Spin Fluctuation and Unconventional Superconductivity in Rb2Cr3As3 Revealed by 75As NMR and NQR.

    PubMed

    Yang, J; Tang, Z T; Cao, G H; Zheng, Guo-Qing

    2015-10-01

    We report (75)As nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) studies on the superconductor Rb(2)Cr(3)As(3) with a quasi-one-dimensional crystal structure. Below T∼100  K, the spin-lattice relaxation rate (1/T(1)) divided by temperature, 1/T(1)T, increases upon cooling down to T(c)=4.8  K, showing a Curie-Weiss-like temperature dependence. The Knight shift also increases with decreasing temperature. These results suggest ferromagnetic spin fluctuation. In the superconducting state, 1/T(1) decreases rapidly below T(c) without a Hebel-Slichter peak, and follows a T(5) variation below T∼3  K, which points to unconventional superconductivity with point nodes in the gap function. PMID:26551818

  7. Ferromagnetic Spin Fluctuation and Unconventional Superconductivity in Rb2Cr3As3 Revealed by 75As NMR and NQR

    NASA Astrophysics Data System (ADS)

    Yang, J.; Tang, Z. T.; Cao, G. H.; Zheng, Guo-qing

    2015-10-01

    We report 75As nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) studies on the superconductor Rb2Cr3As3 with a quasi-one-dimensional crystal structure. Below T ˜100 K , the spin-lattice relaxation rate (1 /T1 ) divided by temperature, 1 /T1T , increases upon cooling down to Tc=4.8 K , showing a Curie-Weiss-like temperature dependence. The Knight shift also increases with decreasing temperature. These results suggest ferromagnetic spin fluctuation. In the superconducting state, 1 /T1 decreases rapidly below Tc without a Hebel-Slichter peak, and follows a T5 variation below T ˜3 K , which points to unconventional superconductivity with point nodes in the gap function.

  8. Mechanical Resonators for Quantum Optomechanics Experiments at Room Temperature

    NASA Astrophysics Data System (ADS)

    Norte, R. A.; Moura, J. P.; Gröblacher, S.

    2016-04-01

    All quantum optomechanics experiments to date operate at cryogenic temperatures, imposing severe technical challenges and fundamental constraints. Here, we present a novel design of on-chip mechanical resonators which exhibit fundamental modes with frequencies f and mechanical quality factors Qm sufficient to enter the optomechanical quantum regime at room temperature. We overcome previous limitations by designing ultrathin, high-stress silicon nitride (Si3 N4 ) membranes, with tensile stress in the resonators' clamps close to the ultimate yield strength of the material. By patterning a photonic crystal on the SiN membranes, we observe reflectivities greater than 99%. These on-chip resonators have remarkably low mechanical dissipation, with Qm˜108, while at the same time exhibiting large reflectivities. This makes them a unique platform for experiments towards the observation of massive quantum behavior at room temperature.

  9. Hafnium Resonance Parameter Analysis using Neutron Capture and Transmission Experiments

    SciTech Connect

    Trbovich, Michael J.; Barry, Devin P.; Burke, John A.; Drindak, Noel J.; Leinweber, Greg; Ballad, Robert V.; Slovacek, Rudy E.; Danon, Yaron; Block, Robert C.

    2005-05-24

    The focus of this work is to determine resonance parameters for stable hafnium isotopes in the 0.005-200 eV region, with special emphasis on the overlapping 176Hf and 178Hf resonances near 8 eV. The large neutron cross section of hafnium, combined with its corrosion resistance and excellent mechanical properties, make it a useful material for controlling nuclear reactions.Experiments measuring neutron capture and transmission were performed at the Rensselaer Polytechnic Institute (RPI) electron linear accelerator (LINAC) using the time of flight method. 6Li glass scintillation detectors were used for transmission experiments at flight path lengths of 15 and 25 m. Capture experiments were done using a sixteen-section NaI(Tl) multiplicity detector at a flight path length of 25 m. These experiments utilized various thicknesses of metallic and isotopically enriched liquid samples. The liquid samples were designed to provide information on the 176Hf and 178Hf contributions to the 8-eV doublet without saturation.Data analysis was done using the R-matrix Bayesian code SAMMY version M6 beta. SAMMY is able to account for experimental resolution effects for each of the experimental setups at the RPI LINAC, and also can correct for multiple scattering effects in neutron capture yield data. The combined capture and transmission data analysis yielded resonance parameters for all hafnium isotopes from 0.005-200 eV. Resonance integrals were calculated along with errors for each hafnium isotope using the NJOY and INTER codes. The isotopic resonance integrals calculated were significantly different than previously published values; however the calculated elemental hafnium resonance integral changed very little.

  10. Dynamic nuclear polarization in a magnetic resonance force microscope experiment.

    PubMed

    Issac, Corinne E; Gleave, Christine M; Nasr, Paméla T; Nguyen, Hoang L; Curley, Elizabeth A; Yoder, Jonilyn L; Moore, Eric W; Chen, Lei; Marohn, John A

    2016-03-23

    We report achieving enhanced nuclear magnetization in a magnetic resonance force microscope experiment at 0.6 tesla and 4.2 kelvin using the dynamic nuclear polarization (DNP) effect. In our experiments a microwire coplanar waveguide delivered radiowaves to excite nuclear spins and microwaves to excite electron spins in a 250 nm thick nitroxide-doped polystyrene sample. Both electron and proton spin resonance were observed as a change in the mechanical resonance frequency of a nearby cantilever having a micron-scale nickel tip. NMR signal, not observable from Curie-law magnetization at 0.6 T, became observable when microwave irradiation was applied to saturate the electron spins. The resulting NMR signal's size, buildup time, dependence on microwave power, and dependence on irradiation frequency was consistent with a transfer of magnetization from electron spins to nuclear spins. Due to the presence of an inhomogeneous magnetic field introduced by the cantilever's magnetic tip, the electron spins in the sample were saturated in a microwave-resonant slice 10's of nm thick. The spatial distribution of the nuclear polarization enhancement factor ε was mapped by varying the frequency of the applied radiowaves. The observed enhancement factor was zero for spins in the center of the resonant slice, was ε = +10 to +20 for spins proximal to the magnet, and was ε = -10 to -20 for spins distal to the magnet. We show that this bipolar nuclear magnetization profile is consistent with cross-effect DNP in a ∼10(5) T m(-1) magnetic field gradient. Potential challenges associated with generating and using DNP-enhanced nuclear magnetization in a nanometer-resolution magnetic resonance imaging experiment are elucidated and discussed. PMID:26964007

  11. Long-term operating experience for the ATLAS superconducting resonators

    SciTech Connect

    Pardo, R.; Zinkann, G.

    1999-12-21

    Portions of the ATLAS accelerator have been operating now for over 21 years. The facility has accumulated several million resonator-hours of operation at this point and has demonstrated the long-term reliability of RF superconductivity. The overall operating performance of the ATLAS facility has established a level of beam quality, flexibility, and reliability not previously achieved with heavy-ion accelerator facilities. The actual operating experience and maintenance history of ATLAS are presented for ATLAS resonators and associated electronics systems. Solutions to problems that appeared in early operation as well as current problems needing further development are discussed.

  12. Magnetic Field Gradient Calibration as an Experiment to Illustrate Magnetic Resonance Imaging

    ERIC Educational Resources Information Center

    Seedhouse, Steven J.; Hoffmann, Markus M.

    2008-01-01

    A nuclear magnetic resonance (NMR) spectroscopy experiment for the undergraduate physical chemistry laboratory is described that encompasses both qualitative and quantitative pedagogical goals. Qualitatively, the experiment illustrates how images are obtained in magnetic resonance imaging (MRI). Quantitatively, students experience the…

  13. Magnetic Field Gradient Calibration as an Experiment to Illustrate Magnetic Resonance Imaging

    ERIC Educational Resources Information Center

    Seedhouse, Steven J.; Hoffmann, Markus M.

    2008-01-01

    A nuclear magnetic resonance (NMR) spectroscopy experiment for the undergraduate physical chemistry laboratory is described that encompasses both qualitative and quantitative pedagogical goals. Qualitatively, the experiment illustrates how images are obtained in magnetic resonance imaging (MRI). Quantitatively, students experience the

  14. A versatile computer-controlled pulsed nuclear quadrupole resonance spectrometer

    NASA Astrophysics Data System (ADS)

    Fisher, Gregory; MacNamara, Ernesto; Santini, Robert E.; Raftery, Daniel

    1999-12-01

    A new, pulsed nuclear quadrupole resonance (NQR) spectrometer capable of performing a variety of pulsed and swept experiments is described. The spectrometer features phase locked, superheterodyne detection using a commercial spectrum analyzer and a fully automatic, computer-controlled tuning and matching network. The tuning and matching network employs stepper motors which turn high power air gap capacitors in a "moving grid" optimization strategy to minimize the reflected power from a directional coupler. In the duplexer circuit, digitally controlled relays are used to switch different lengths of coax cable appropriate for the different radio frequencies. A home-built pulse programmer card controls the timing of radio frequency pulses sent to the probe, while data acquisition and control software is written in Microsoft Quick Basic. Spin-echo acquisition experiments are typically used to acquire the data, although a variety of pulse sequences can be employed. Scan times range from one to several hours depending upon the step resolution and the spectral range required for each experiment. Pure NQR spectra of NaNO2 and 3-aminopyridine are discussed.

  15. Nuclear quadrupole resonance lineshape analysis for different motional models: Stochastic Liouville approach

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

    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), 10.1006/jmre.2000.2125] 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.

  16. Experiments on statistical mechanics using resonance ionization spectroscopy

    SciTech Connect

    Iturbe, J.; Allman, S.L.; Hurst, G.S.; Payne, M.G.

    1984-04-01

    Five different fluctuation phenomena at the atomic and molecular levels have been studied by resonance ionization spectroscopy techniques with one-atom detection sensitivity. The Poisson distribution described the observed frequency distributions suggesting random behavior. In addition, a gedanken experiment suggested by Einstein and Furth on the diffusion of atoms was performed in order to test the equality between time and ensemble averages. The obtained results confirmed the ergodicity of the studied system.

  17. Closing supersymmetric resonance regions with direct detection experiments

    SciTech Connect

    Kelso, Chris

    2014-01-01

    One of the few remaining ways that neutralinos could potentially evade constraints from direct detection experiments is if they annihilate through a resonance, as can occur if 2m{sub χ⁰} falls within about ~10% of either m{sub A/H}, m{sub h}, or m{sub Z}. Assuming a future rate of progress among direct detection experiments that is similar to that obtained over the past decade, we project that within 7 years the light Higgs and Z pole regions will be entirely closed, while the remaining parameter space near the A/H resonance will require that 2m{sub χ₀} be matched to the central value (near m{sub A}) to within less than 4%. At this rate of progress, it will be a little over a decade before multi-ton direct detection experiments will be able to close the remaining, highly-tuned, regions of the A/H resonance parameter space.

  18. 35C NQR studies in 2,4,6-,2,3,6-, and 2,3,4-trichloro anisoles

    NASA Astrophysics Data System (ADS)

    Rukmani, K.; Ramakrishna, J.

    1985-02-01

    The chlorine-35 NQR frequencies and their temperature variation in 2,4,6-, 2,3,6- and 2,3,4-trichloro anisoles have been studied and compared with the corresponding chlorophenols with a view to studying the effect of hydrogen bonding. The observed frequencies have been assigned to the various chlorines with the help of the additive model of the substituent effect. The temperature dependence has been analysed in terms of the BayerKushidaBrown models. The torsional frequencies and their temperature dependence have been calculated numerically under a two mode approximation. A comparison of the trichloro anisoles with the corresponding trichloro phenols has shown that the resonance frequency decreases due to hydrogen bonding while the torsional frequencies are not affected.

  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.

    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.

  20. Studies of Ga NMR and NQR in SrGa4

    NASA Astrophysics Data System (ADS)

    Niki, H.; Higa, N.; Nakamura, S.; Kuroshima, H.; Toji, T.; Yogi, M.; Nakamura, A.; Hedo, M.; Nakama, T.; Ōnuki, Y.; Harima, H.

    2015-04-01

    In order to microscopically investigate the properties in SrGa4, the Ga NMR measurements of a powder sample were carried out. The Ga NMR spectra corresponding to Ga(I) and Ga(II) sites are obtained. The NMR spectra of 69&71Ga (a nuclear spin I = 3/2) in the powder sample of SrGa4 do not take a typical powder pattern caused by the NQR interaction, but take the spectra consisting of three well resolved resonance-lines, which indicates that the nonuniform distribution of crystal orientation in the powder sample occurs because of the magnetic anisotropy. From the analysis of the Ga NMR spectrum, it is found that the ab-plane of the crystal is parallel to the external magnetic field, which would be attributed to the anisotropy of the magnetic susceptibility with the easy axis parallel to the ab-plane. This result is also confirmed by the 69Ga NQR in SrGa4. The Knight shifts of the 69Ga(I) and 69Ga(II) shift slightly to the negative side with decreasing temperature due to the core polarization of the d-electrons. The values of the Knight shift of the 69Ga(I) and 69Ga(II) are 0.01 and -0.11 % at 4.2 K, and 0.09 and -0.08 % at 300 K, respectively. The values of the 1/ T 1 T of the NMR of both 69Ga(I) and 69Ga(II) are almost constant between 4.2 and 100 K, whose values are 1.5 s -1 K -1 at 69Ga(I) and 0.12 s -1 K -1 at 69Ga(II), while the 1/ T 1 T slightly increase above 100K with increasing temperature. The value of T 1 of 69Ga(I) is one order of magnitude less than that of 69Ga(II).

  1. Phase Dependence of Double-Resonance Experiments in Rotational Spectroscopy.

    PubMed

    Schmitz, David; Shubert, V Alvin; Patterson, David; Krin, Anna; Schnell, Melanie

    2015-04-16

    We here report on double-resonance experiments using broadband chirped pulse Fourier transform microwave spectroscopy that can facilitate spectral assignment and yield information about weak transitions with high resolution and sensitivity. Using the diastereomers menthone and isomenthone, we investigate the dependence of pumping a radio frequency transition on both the amplitude and phase of the signal from a microwave transition with which it shares a common rotational level. We observe a strong phase change when scanning the radio frequency through molecular resonance. The direction of the phase change depends on the energy level arrangement, that is, if it is progressive or regressive. The experimental results can be simulated using the three-level optical Bloch equations and described with the AC Stark effect, giving rise to an Autler-Townes splitting. PMID:26263157

  2. Thomson’s ring experiment with resonant LC circuit

    NASA Astrophysics Data System (ADS)

    Haidar, Sajjad

    2016-01-01

    Thomson’s jumping ring experiment is conducted using a low voltage (24 V) electronic circuit. A coil (L) is connected with a capacitor (C) in parallel and is driven at its resonant frequency to obtain a high current in the coil. A circuit sends current pulses to the LC tank circuit at around its resonant frequency. The oscillating current in the coil induces a voltage in a copper-loop on top of it. The induced current interacts with the radial part of the coil-magnetic field; the resulting force levitates the loop. In a separate coil, a ferrite core and a copper ring are used to demonstrate the jumping-ring effect. The levitation and the jumping effect can be controlled by changing the duty cycle and frequency. In this report simple formulae and approximations are used to calculate the levitating force on the loop.

  3. Experiment study of an electron cyclotron resonant ion source based on a tapered resonance cavity

    SciTech Connect

    Yang, Juan; Shi, Feng; Jin, Yizhou; Wang, Yunmin; Komurasaki, Kimiya

    2013-12-15

    Electron cyclotron resonant plasma is one type of magnetised plasma generated by continuous microwave energy. It has the property of high degree of ionization and large volume at low gas pressure, which makes it useful for space propulsion and material processing. This article presents the experiment study of the plasma properties and ion beam extraction from an electron cyclotron resonant ion source based on a tapered resonance cavity. Optical emission spectroscopy based on a simple collisional radiation model was used for plasma diagnosis. Experiment results show that, at microwave power setting ranging from 7.06 to 17.40 W and mass flow rate ranging from 1 to 10 sccm, argon gas can be ionized. Ion beam of 109.1 mA from the ion source can be extracted at microwave power of 30 W, mass flow rate of 10 sccm, and accel voltage of 800 V. The diagnosed plasma temperature and density are 2.4–5.2 eV and 2 × 10{sup 16}–4.8 × 10{sup 17} m{sup −3}, respectively.

  4. Anisotropic spin fluctuations and anomalies of nuclear quadrupole interactions in the itinerant antiferromagnet NpCoGa5 : Co59 NMR and Ga69,71 NMR/NQR studies

    NASA Astrophysics Data System (ADS)

    Sakai, Hironori; Kambe, Shinsaku; Tokunaga, Yo; Fujimoto, Tatsuya; Walstedt, Russell E.; Yasuoka, Hiroshi; Aoki, Dai; Homma, Yoshiya; Yamamoto, Etsuji; Nakamura, Akio; Shiokawa, Yoshinobu; Ōnuki, Yoshichika

    2007-07-01

    Nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) experiments have been performed on a single crystal of tetragonal NpCoGa5 , an itinerant antiferromagnet with a Néel temperature TN=47K . The antiferromagnetic phase is inverted to a field-induced ferromagnetic (FIF) phase with an applied field (H0) above Hm (T→0) ˜40kOe oriented along the c axis. NMR spectra have been measured above and below TN with H0‖c and a axes and have been assigned to Ga69,71 nuclei on two crystallographically inequivalent 1c and 4i sites and to Co59 nuclei on the 1b site. Using second-order perturbation calculations, Knight shift (K) , electric field gradient (EFG), frequency (νQ) , and asymmetry parameter (η) of the EFG are deduced for each site. These parameters for the Ga69(1c) and Ga69,71(4i) sites are confirmed by NQR measurements in zero field. The Knight shifts obtained in the paramagnetic (PM) state obey a Curie-Weiss law, which scales with the bulk susceptibility (χ) . Hyperfine tensors for each site are deduced from K-χ plots with temperature as an implicit parameter. Antiferromagnetic NMR spectra in zero field were also observed, finding an internal field of ˜20kOe at the Ga(4i) site at the lowest temperature. The ordered moment can be estimated from this to be 0.81μB/Np . The nuclear quadrupolar parameters ( νQ and η ) are found to exhibit an anomaly just below TN in the FIF phase. T1 and T2 have been measured for each site. For H0‖c , T1˜constant behavior suggests localized 5f character for T>100K and itinerant (1/T1∝T) behavior for TN

  5. On experimenting with functional magnetic resonance imaging of lip movement.

    PubMed

    Satheeshkumar, J; Rajesh, R; Arumugaperumal, S; Kesavdas, C

    2008-02-18

    The analysis of functional magnetic resonance imaging (fMRI) time-series data can provide information on task-related activities, functional/effective connectivity among regions and the influences of behavioral/physiologic states on connectivity. This paper illustrates the importance of the neurobiological constraints involved in using statistical parametric mapping (SPM) through Matlab simulation and thus helping the radiologist to interpret the results better. This paper also presents the results and inferences from neuroimaging data of the lip movement experiment using statistical parametric mapping (SPM). The results match with the sensory/motor activation atlas by Penfield and Rasmussen (1950). PMID:24256746

  6. Dependence of nuclear quadrupole resonance transitions on the electric field gradient asymmetry parameter for nuclides with half-integer spins

    DOE PAGESBeta

    Cho, Herman

    2016-02-28

    Allowed transition energies and eigenstate expansions have been calculated and tabulated in numerical form as functions of the electric field gradient asymmetry parameter for the zero field Hamiltonian of quadrupolar nuclides with I = 3/2,5/2,7/2, and 9/2. These results are essential to interpret nuclear quadrupole resonance (NQR) spectra and extract accurate values of the electric field gradient tensors. Furthermore, applications of NQR methods to studies of electronic structure in heavy element systems are proposed.

  7. Coexistence of multiple charge-density waves and superconductivity in SrPt2As2 revealed by 75As-NMR /NQR and 195Pt-NMR

    NASA Astrophysics Data System (ADS)

    Kawasaki, Shinji; Tani, Yoshihiko; Mabuchi, Tomosuke; Kudo, Kazutaka; Nishikubo, Yoshihiro; Mitsuoka, Daisuke; Nohara, Minoru; Zheng, Guo-qing

    2015-02-01

    The relationship between charge-density wave (CDW) orders and superconductivity in arsenide superconductor SrPt2As2 with Tc=5.2 K which crystallizes in the CaBe2Ge2 -type structure was studied by 75As nuclear magnetic resonance (NMR) measurements up to 520 K, and 75As nuclear quadrupole resonance (NQR) and 195Pt-NMR measurements down to 1.5 K. At high temperature, 75As-NMR spectrum and nuclear-spin-relaxation rate (1 /T1) have revealed two distinct CDW orders, one realized in the As-Pt-As layer below TCDWAs (1 )=410 K and the other in the Pt-As-Pt layer below TCDWAs (2 )=255 K . The 1 /T1 measured by 75As-NQR shows a clear Hebel-Slichter peak just below Tc and decreases exponentially well below Tc. Concomitantly, 195Pt Knight shift decreases below Tc. Our results indicate that superconductivity in SrPt2As2 is in the spin-singlet state with an s -wave gap and is robust under the two distinct CDW orders in different layers.

  8. The Bond N -Cl. A Spectroscopic (35Cl-NQR, IR) Investigation

    NASA Astrophysics Data System (ADS)

    Gowda, B. Thimme; Weiss, Alarich

    1994-06-01

    Chlorine bound to nitrogen is an interesting oxidizing agent in aqueous, partial aqueous and non-aqueous media. One can assume that the oxidizing action of the chlorine depends on the polarization of the Cl atom in the bond N -Cl which will depend on the electron distribution in the ligands R and R″ of the configuration R -NCl -CO -R″. 17 compounds were synthesized with R = substituted phenyl radical C6H5-y Xy, X = Cl, NO2, R″ = CH2Cl. The 35Cl NQR frequencies are observed in the range 52 to 54 MHz (T = 77 K) for the Cl(N) 34 to 37 MHz for the phenyl chlorines and the CH2Cl group. Their temperature dependence was followed up to 300 K. Therefrom the assignment of the resonance to certain Cl-atoms in the molecules is possible. Generally, the substitution of a negative substituent X (Cl, NO2) in the phenyl ring raises the resonance frequencies; the influence of the CH2Cl group on the N -Cl bond is weak. Strong is the influence of the carbonyl group on the N -C l bond. The IR group frequencies ν(C = O) are found in the range 1680 ≤ ν (C = O)/ cm-1≤ 1717, shifted up by ≤ 20 cm-1 compared to the corresponding acetamide R ⎯ NH ⎯CO ⎯ R″. Influence of the phenyl ring substitution on ν (C = O) does not follow a simple law of inductive effect. Also a correlation between the vibration frequencies of the N ⎯ Cl group and the phenyl group substitution is not found.

  9. 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.

  10. Optical Resonators in Current and Future Experiments of the ALPS Collaboration

    SciTech Connect

    Meier, T.

    2010-08-30

    The ALPS collaboration runs a 'light shining through a wall' (LSW) experiment to search for weakly interacting sub-eV particles (WISPs). Its sensitivity is significantly enhanced by the incorporation of a large-scale production resonator and a small-scale high-power resonant second harmonic generator. Here we report on important experimental details and limitations of these resonators and derive recommendations for further experiments. A very promising improvement for a future ALPS experiment is the incorporation of an additional large-scale regeneration resonator. We present a rough sketch of how to combine a regeneration resonator with a single-photon counter (SPC) as detector for regenerated photons.

  11. Pulsed Bromine-81 Nuclear Quadrupole Resonance Spectroscopy of Brominated Flame Retardants and Associated Polymer Blends.

    NASA Astrophysics Data System (ADS)

    Mrse, Anthony A.; Lee, Youngil; Bryant, Pamela L.; Fronczek, Frank R.; Butler, Leslie G.; Simeral, Larry S.

    1998-03-01

    The dispersion of brominated flame retardants in polymers is monitored with bromine-81 NQR using a pulse NQR spectrometer. The NQR spectrometer consists of a homemade 10-300 MHz single-channel NMR console coupled to a broadly tunable probe. The probe is a loop-gap resonator usable from 220 to 300 MHz, and automatically tuned over any 5 MHz region with a stepping motor and an RF bidirectional coupler. Bromine-81 NQR spectra of several brominated aromatic flame retardants, as pure materials and in polymers, were recorded in the range of 227 to 256 MHz in zero applied magnetic field. Two factors affect the bromine-79/81 NQR transition frequencies in brominated aromatics: electron withdrawing substituents on the ring and intermolecular contacts with other bromine atoms in the crystal structure. An existing model for substituents is updated and a point charge model for the intermolecular contacts is developed. In this study, we exploit the bromine-81 NQR transition frequency dependence on intermolecular contacts to learn how a flame retardant is dispersed in a polymer matrix.

  12. 35Cl NQR study of incommensurate state in thiourea-hexachloroethane inclusion compound

    NASA Astrophysics Data System (ADS)

    Panich, A. M.; Semenov, A. R.; Chekhova, G. N.; Krieger, Ju. H.; Goren, S. D.

    1999-04-01

    A study of the incommensurate phase of the channel thiourea-hexachloroethane inclusion compound by means of 35Cl NQR, in the temperature range from 68 to 88 K, is presented. Hahn echo measurements indicate the slow diffusion-like motion of the modulation wave. This motion is obtained close to the transition temperature Ti˜90 K. At higher temperatures, the NQR spectrum is not observed. We attribute this fact to the reorientational mobility of C 2Cl 6 molecules in the host sublattice, probably accompanied by an order-disorder phase transition.

  13. 55Mn NMR/NQR study in β-MnOs alloys

    NASA Astrophysics Data System (ADS)

    Hama, T.; Matsumura, M.; Yamagata, H.; Miyakawa, M.; Umetsu, R.; Fukamichi, K.

    2004-05-01

    The substitutional effects to the site I of Os atom were investigated microscopically by 55Mn zero-field NMR and NQR in β-Mn 1- xOs x alloys. Above the Néel temperature TN, the new set of NQR signal appears in lower frequency, suggesting the local lattice expansion around Os atom in x⩽0.06. Sufficiently below TN, NMR signal associated with the site II appears in x⩾0.005. The internal field increases continuously with increasing x, which is consistent with the picture of itinerant antiferromagnet.

  14. 75As NQR/NMR study for successive transition below TK in CeRhAs

    NASA Astrophysics Data System (ADS)

    Matsumura, M.; Sasakawa, T.; Takabatake, T.; Tsuji, S.; Tou, H.; Sera, M.

    2004-05-01

    75As NQR spectral splitting confirms microscopically the lattice modulations in the successive transitions occurring below TK in a Kondo insulator CeRhAs. Combining the NQR spectra with high-field powder NMR one, the electric field gradient tensor as well as the Knight shift at As site are deduced in the respective phases. The gap appears over the Fermi surface in the ground phase, being different from the V-shaped one in the isostructural CeRhSb and CeNiSn.

  15. Electron cyclotron resonance heating in the microwave tokamak experiment

    SciTech Connect

    Allen, S.L.; Casper, T.A.; Fenstermacher, M.E.

    1992-09-01

    This paper presents the results from a series of Electron Cyclotron Resonance Heating (ECRH) experiments on the Microwave Tokamak Experiment (MTX). On-axis heating at B{sub T} = 5T (f{sub ce} = 140 GHz) has been performed at electron densities up to cutoff. We have used both a long-pulse gryotron ({approximately}200 kW, {approximately}0.1s) and a pulsed Free Electron Laser (FEL) as microwave sources. Gyrotron experiments with power densities corresponding to 4 MW m{sup {minus}3}. A far infrared (FIR) polarimeter measured peaking of plasma current profiles in some discharges during the ECRH pulse. During high-power single-pulse FEL experiments, single-pass microwave !transmission measurements show nonlinear effects; i.e., higher transmission than predicted by linear theory. A corrugated-wall duct was used in the tokamak port to increase the gradient of the parallel refractive index n{sub parallel} of the incident wave, and increased absorption was observed. Evidence of electron tail heating during FEL pulses was observed on soft x-ray and ECE diagnostics. These results are in agreement with predictions of nonlinear theory; extrapolation of this theory to reactor-like conditions indicates efficient absorption and heating. A Laser Assisted Particle Probe Spectroscopy (LAPPS) diagnostic provided estimates of the vacuum electric field of the FEL which were consistent with the measured power. Multiple pulse operation of the ETA-II accelerator for the FEL has also been demonstrated, indicating the feasibility of high-average power FEL operation.

  16. Suppression of electron correlations in the collapsed tetragonal phase of CaFe2As2 under ambient pressure demonstrated by As75 NMR/NQR measurements

    NASA Astrophysics Data System (ADS)

    Furukawa, Y.; Roy, B.; Ran, S.; Bud'ko, S. L.; Canfield, P. C.

    2014-03-01

    The static and the dynamic spin correlations in the low-temperature collapsed tetragonal and the high-temperature tetragonal phase in CaFe2As2 have been investigated by As75 nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements. Through the temperature (T) dependence of the nuclear spin lattice relaxation rates (1/T1) and the Knight shifts, although stripe-type antiferromagnetic (AFM) spin correlations are realized in the high-temperature tetragonal phase, no trace of the AFM spin correlations can be found in the nonsuperconducting, low-temperature, collapsed tetragonal (cT) phase. Given that there is no magnetic broadening in As75 NMR spectra, together with the T-independent behavior of magnetic susceptibility χ and the T dependence of 1/T1Tχ, we conclude that Fe spin correlations are completely quenched statically and dynamically in the nonsuperconducting cT phase in CaFe2As2.

  17. Suppression of electron correlations in the collapsed tetragonal phase of CaFe2As2 under ambient pressure demonstrated by As75 NMR/NQR measurements

    SciTech Connect

    Furukawa, Yuji; Roy, Beas; Ran, Sheng; Budko, Sergey L.; Canfield, Paul C.

    2014-03-20

    The static and the dynamic spin correlations in the low-temperature collapsed tetragonal and the high-temperature tetragonal phase in CaFe2As2 have been investigated by As75 nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements. Through the temperature (T) dependence of the nuclear spin lattice relaxation rates (1/T1) and the Knight shifts, although stripe-type antiferromagnetic (AFM) spin correlations are realized in the high-temperature tetragonal phase, no trace of the AFM spin correlations can be found in the nonsuperconducting, low-temperature, collapsed tetragonal (cT) phase. Given that there is no magnetic broadening in As75 NMR spectra, together with the T-independent behavior of magnetic susceptibility χ and the T dependence of 1/T1Tχ, we conclude that Fe spin correlations are completely quenched statically and dynamically in the nonsuperconducting cT phase in CaFe2As2.

  18. Resonant solar neutrino oscillation versus laboratory neutrino oscillation experiments

    SciTech Connect

    Lim, Chong-Sa

    1987-02-01

    The interplay between resonant solar neutrino oscillations and neutrino oscillations in laboratory experiments is investigated in a 3 generation model. Due to the assumed hierarchy of neutrino masses, together with our choice of a convenient parameterization of the 3 generation mixing matrix, we can derive a simple analytic formula which reduces the solar neutrino problem to an effective 2 generation problem. The reduction makes it apparent that the allowed range of mixing and mass parameters crucially depend on whether the survival probability of solar neutrinos S satisfies S greater than or equal to 1/3 or not. The formulae for probabilities of laboratory neutrino oscillations are also greatly simplified. We argue that a combination of the observed solar neutrino depletion and data obtained from reactor experiments seems to rule out some range of neutrino masses. If a sizable nu/sub ..mu../ ..-->.. nu/sub e/ oscillation is observed at accelerators, as suggested at this Workshop, it severely restricts the range of 2 mixing angles.

  19. Electronic properties of Y-Ba-Cu-O superconductors as seen by Cu and O NMR/NQR

    NASA Technical Reports Server (NTRS)

    Brinkmann, D.

    1995-01-01

    Nuclear Magnetic Resonance (NMR) and Nuclear Quadrupole Resonance (NQR) allow the investigation of electronic properties at the atomic level. We will report on such studies of typical members of the the Y-Ba-Cu-O family such as YBa2Cu30(6 + x) (1-2-3-(6 + x)), YBa2Cu4O8 (1-2-4) and Y2Ba4Cu7015 (2-4-7) with many examples of recent work performed in our laboratory. In particular, we will deal with Knight shift and relaxation studies of copper and oxygen. We will discuss important issues of current studies such as: (1) Existence of a common electronic spin-susceptibility in the planes (and perhaps in the chains) of 1-2-4; (2) Strong evidence for the existence of a pseudo spin-gap of the antiferromagnetic fluctuations in 1-2-4 and 2-4-7; (3) Evidence for d-wave pairing in 1-2-4; (4) Strong coupling of inequivalent Cu-O planes in 2-4-7 and possible origin for the high Tc value of this compound; and (5) The possibility to describe NMR data in the framework of a charge-excitation picture.

  20. Magnetic resonance imaging of the female pelvis: initial experience

    SciTech Connect

    Hricak, H.; Alpers, C.; Crooks, L.E.; Sheldon, P.E.

    1983-12-01

    The potential of magnetic resonance imaging (MRI) was evaluated in 21 female subjects: seven volunteers, 12 patients scanned for reasons unrelated to the lower genitourinary tract, and two patients referred with gynecologic disease. The uterus at several stages was examined; the premenarcheal uterus (one patient), the uterus of reproductive age (12 patients), the postmenopausal uterus (two patients), and in an 8 week pregnancy (one patient). The myometrium and cyclic endometrium in the reproductive age separated by a low-intensity line (probably stratum basale), which allows recognition of changes in thickness of the cyclic endometrium during the menstrual cycle. The corpus uteri can be distinguished from the cervix by the transitional zone of the isthmus. The anatomic relation of the uterus to bladder and rectum is easily outlined. The vagina can be distinguished from the cervix, and the anatomic display of the closely apposed bladder, vagina, and rectum is clear on axial and coronal images. The ovary is identified; the signal intensity from the ovary depends on the acquisition parameter used. Uterine leiomyoma, endometriosis, and dermoid cyst were depicted, but further experience is needed to ascertain the specificity of the findings.

  1. 35Cl NQR and Crystal Structure Studies of Salts of Chlorodifluoro- and Dichloroacetic Acid

    NASA Astrophysics Data System (ADS)

    Basaran, Reha; Dou, Shi-qi; Weiss, Alarich

    1992-02-01

    The 35Cl NQR spectra of several chlorodifluoroacetates were studied as a function of temperature, including the acid ClF2CCOOH. The cations were: Ammonium, guanidinium, paramethylanilinium. Also some acid salts M⊕ClF2CCOO⊖ • n - ClF2CCOOH ( n > l ) were studied by 35Cl NQR. The bleaching temperatures of the NQR signals were determined. In the para-methylanilinium salt and in the guanidinium salt a phase transition has been observed. The crystal structure of guanidinium chlorodifluoroacetate has been determined at room temperature (a = 1089 pm, 6 = 845 pm, c = 832 pm, space group Pnma, Z = 4). For comparison, guanidinium dichloroacetate was studied by 35Cl NQR and by X-ray diffraction, too: P21/c, Z = 4 , a = 804pm, b = 1202 pm, c = 1080 pm, ß = 131.58°. For guanidinium chlorodifluoroacetate and chlorodifluoroacetic acid, the 35Cl spin lattice relaxation time T1 and the line width have been followed up as a function of temperature. Therefrom, the activation energies of the reorientation motion of the group -CF2C1 have been determined to be 14 kJ • mol-1 (from T1) and 12.5 kJ • mol- 1 (from Δv) for the pure acid and 9.2 kJ • mol-1 and 8.8 kJ • mol-1 , respectively, for the guanidinium salt.

  2. Structural Isomer Identification via NMR: A Nuclear Magnetic Resonance Experiment for Organic, Analytical, or Physical Chemistry.

    ERIC Educational Resources Information Center

    Szafran, Zvi

    1985-01-01

    Background information, procedures used, and typical results obtained are provided for an experiment that examines the ability of nuclear magnetic resonance (NMR) to distinguish between structural isomers via resonance multiplicities and chemical shifts. Reasons for incorporating the experiment into organic, analytical, or physical chemistry…

  3. 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.

  4. The Conformational Changes Induced by Ubiquinone Binding in the Na+-pumping NADH:Ubiquinone Oxidoreductase (Na+-NQR) Are Kinetically Controlled by Conserved Glycines 140 and 141 of the NqrB Subunit*

    PubMed Central

    Strickland, Madeleine; Juárez, Oscar; Neehaul, Yashvin; Cook, Darcie A.; Barquera, Blanca; Hellwig, Petra

    2014-01-01

    Na+-pumping NADH:ubiquinone oxidoreductase (Na+-NQR) is responsible for maintaining a sodium gradient across the inner bacterial membrane. This respiratory enzyme, which couples sodium pumping to the electron transfer between NADH and ubiquinone, is not present in eukaryotes and as such could be a target for antibiotics. In this paper it is shown that the site of ubiquinone reduction is conformationally coupled to the NqrB subunit, which also hosts the final cofactor in the electron transport chain, riboflavin. Previous work showed that mutations in conserved NqrB glycine residues 140 and 141 affect ubiquinone reduction and the proper functioning of the sodium pump. Surprisingly, these mutants did not affect the dissociation constant of ubiquinone or its analog HQNO (2-n-heptyl-4-hydroxyquinoline N-oxide) from Na+-NQR, which indicates that these residues do not participate directly in the ubiquinone binding site but probably control its accessibility. Indeed, redox-induced difference spectroscopy showed that these mutations prevented the conformational change involved in ubiquinone binding but did not modify the signals corresponding to bound ubiquinone. Moreover, data are presented that demonstrate the NqrA subunit is able to bind ubiquinone but with a low non-catalytically relevant affinity. It is also suggested that Na+-NQR contains a single catalytic ubiquinone binding site and a second site that can bind ubiquinone but is not active. PMID:25006248

  5. Liquid contact resonance AFM: analytical models, experiments, and limitations

    NASA Astrophysics Data System (ADS)

    Parlak, Zehra; Tu, Qing; Zauscher, Stefan

    2014-11-01

    Contact resonance AFM (CR-AFM) is a scanning probe microscopy technique that utilizes the contact resonances of the AFM cantilever for concurrent imaging of topography and surface stiffness. The technique has not been used in liquid until recently due to analytical and experimental difficulties, associated with viscous damping of cantilever vibrations and fluid loading effects. To address these difficulties, (i) an analytical approach for contact resonances in liquid is developed, and (ii) direct excitation of the contact resonances is demonstrated by actuating the cantilever directly in a magnetic field. By implementing the analytical approach and the direct actuation through magnetic particles, quantitative stiffness imaging on surfaces with a wide range of stiffness can be achieved in liquid with soft cantilevers and low contact forces.

  6. Temperature variation of ultralow frequency modes and mean square displacements in solid lasamide (diuretic drug) studied by 35Cl-NQR, X-ray and DFT/QTAIM.

    PubMed

    Latosińska, Jolanta Natalia; Latosińska, Magdalena; Kasprzak, Jerzy; Tomczak, Magdalena; Maurin, Jan Krzysztof

    2012-10-25

    The application of combined (35)Cl-NQR/X-ray/DFT/QTAIM methods to study the temperature variation of anisotropic displacement parameters and ultralow frequency modes of anharmonic torsional vibrations in the solid state is illustrated on the example of 2,4-dichloro-5-sulfamolybenzoic acid (lasamide, DSBA) which is a diuretic and an intermediate in the synthesis of furosemide and thus its common impurity. The crystallographic structure of lasamide is solved by X-ray diffraction and refined to a final R-factor of 3.06% at room temperature. Lasamide is found to crystallize in the triclinic space group P-1, with two equivalent molecules in the unit cell a = 7.5984(3) Å, b = 8.3158(3) Å, c = 8.6892(3) Å; α = 81.212(3)°, β = 73.799(3)°, γ = 67.599(3)°. Its molecules form symmetric dimers linked by two short and linear intermolecular hydrogen bonds O-H···O (O-H···O = 2.648 Å and ∠OHO = 171.5°), which are further linked by weaker and longer intermolecular hydrogen bonds N-H···O (N-H···O = 2.965 Å and ∠NHO = 166.4°). Two (35)Cl-NQR resonance frequencies, 36.899 and 37.129 MHz, revealed at room temperature are assigned to chlorine sites at the ortho and para positions, relative to the carboxyl functional group, respectively. The difference in C-Cl(1) and C-Cl(2) bond lengths only slightly affects the value of (35)Cl-NQR frequencies, which results mainly from chemical inequivalence of chlorine atoms but also involvement in different intermolecular interactions pattern. The smooth decrease in both (35)Cl-NQR frequencies with increasing temperature in the range of 77-300 K testifies to the averaging of EFG tensor at each chlorine site due to anharmonic torsional vibrations. Lasamide is thermally stable; no temperature-induced release of chlorine or decomposition of this compound is detected. The temperature dependence of ultralow frequency modes of anharmonic small-angle internal torsional vibrations averaging EFG tensor and mean square angle displacements at both chlorine sites is derived from the (35)Cl-NQR temperature dependence. The frequencies of torsional vibrations higher for the para site than the ortho site are in good agreement with those obtained from thermal parameters obtained from X-ray studies. The mean square angle displacements are in good agreement with those estimated from X-ray data with the use of the TLS model. The detailed DFT/QTAIM analysis suggests that the interplay between different hydrogen bonds in adjacent molecules forming dimers is responsible for the differences in flexibility of the carboxyl and sulphonamide substituents as well as both C-Cl(1) and C-Cl(2) bonds. Three ultralow wavenumber modes of internal vibrations in Raman and IR spectra obtained at the B3LYP/6-311++G(d,p) level close to those obtained within the TLS model suggest that internal and external modes of vibrations are not well separated. PMID:23020838

  7. Low-frequency nuclear quadrupole resonance with a dc SQUID

    SciTech Connect

    Chang, J.W.

    1991-07-01

    Conventional pure nuclear quadrupole resonance (NQR) is a technique well suited for the study of very large quadrupolar interactions. Numerous nuclear magnetic resonance (NMR) techniques have been developed for the study of smaller quadrupolar interactions. However, there are many nuclei which have quadrupolar interactions of intermediate strength. Quadrupolar interactions in this region have traditionally been difficult or unfeasible to detect. This work describes the development and application of a SQUID NQR technique which is capable of measuring intermediate strength quadrupolar interactions, in the range of a few hundred kilohertz to several megahertz. In this technique, a dc SQUID (Superconducting QUantum Interference Device) is used to monitor the longitudinal sample magnetization, as opposed to the transverse magnetization, as a rf field is swept in frequency. This allows the detection of low-frequency nuclear quadrupole resonances over a very wide frequency range with high sensitivity. The theory of this NQR technique is discussed and a description of the dc SQUID system is given. In the following chapters, the spectrometer is discussed along with its application to the study of samples containing half-odd-integer spin quadrupolar nuclei, in particular boron-11 and aluminum-27. The feasibility of applying this NQR technique in the study of samples containing integer spin nuclei is discussed in the last chapter. 140 refs., 46 figs., 6 tabs.

  8. Modeling Nonlinear Acoustic Standing Waves in Resonators: Theory and Experiments

    NASA Technical Reports Server (NTRS)

    Raman, Ganesh; Li, Xiaofan; Finkbeiner, Joshua

    2004-01-01

    The overall goal of the cooperative research with NASA Glenn is to fundamentally understand, computationally model, and experimentally validate non-linear acoustic waves in enclosures with the ultimate goal of developing a non-contact acoustic seal. The longer term goal is to transition the Glenn acoustic seal innovation to a prototype sealing device. Lucas and coworkers are credited with pioneering work in Resonant Macrosonic Synthesis (RMS). Several Patents and publications have successfully illustrated the concept of Resonant Macrosonic Synthesis. To utilize this concept in practical application one needs to have an understanding of the details of the phenomenon and a predictive tool that can examine the waveforms produced within resonators of complex shapes. With appropriately shaped resonators one can produce un-shocked waveforms of high amplitude that would result in very high pressures in certain regions. Our goal is to control the waveforms and exploit the high pressures to produce an acoustic seal. Note that shock formation critically limits peak-to-peak pressure amplitudes and also causes excessive energy dissipation. Proper shaping of the resonator is thus critical to the use of this innovation.

  9. 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.

  10. Dynamical control near resonances in gedanken experiments using varying projectile flux

    SciTech Connect

    Kapralova-Zdanska, Petra R.

    2006-06-15

    We show that the complex scaling method for resonances is equivalent to carrying out a gedanken experiment, where particles are scattered by a target with the incoming flux not being constant as usual but exponentially reduced in time at the rate {gamma}. Resonances are examined at discrete energy levels, while a counterintuitive reverse dynamical control is demonstrated off these levels for {gamma} greater than the resonance decay rate {gamma}{sub r}.

  11. Flow-excited acoustic resonance of a Helmholtz resonator: Discrete vortex model compared to experiments

    SciTech Connect

    Dai, Xiwen; Jing, Xiaodong Sun, Xiaofeng

    2015-05-15

    The acoustic resonance in a Helmholtz resonator excited by a low Mach number grazing flow is studied theoretically. The nonlinear numerical model is established by coupling the vortical motion at the cavity opening with the cavity acoustic mode through an explicit force balancing relation between the two sides of the opening. The vortical motion is modeled in the potential flow framework, in which the oscillating motion of the thin shear layer is described by an array of convected point vortices, and the unsteady vortex shedding is determined by the Kutta condition. The cavity acoustic mode is obtained from the one-dimensional acoustic propagation model, the time-domain equivalent of which is given by means of a broadband time-domain impedance model. The acoustic resistances due to radiation and viscous loss at the opening are also taken into account. The physical processes of the self-excited oscillations, at both resonance and off-resonance states, are simulated directly in the time domain. Results show that the shear layer exhibits a weak flapping motion at the off-resonance state, whereas it rolls up into large-scale vortex cores when resonances occur. Single and dual-vortex patterns are observed corresponding to the first and second hydrodynamic modes. The simulation also reveals different trajectories of the two vortices across the opening when the first and second hydrodynamic modes co-exist. The strong modulation of the shed vorticity by the acoustic feedback at the resonance state is demonstrated. The model overestimates the pressure pulsation amplitude by a factor 2, which is expected to be due to the turbulence of the flow which is not taken into account. The model neglects vortex shedding at the downstream and side edges of the cavity. This will also result in an overestimation of the pulsation amplitude.

  12. Flow-excited acoustic resonance of a Helmholtz resonator: Discrete vortex model compared to experiments

    NASA Astrophysics Data System (ADS)

    Dai, Xiwen; Jing, Xiaodong; Sun, Xiaofeng

    2015-05-01

    The acoustic resonance in a Helmholtz resonator excited by a low Mach number grazing flow is studied theoretically. The nonlinear numerical model is established by coupling the vortical motion at the cavity opening with the cavity acoustic mode through an explicit force balancing relation between the two sides of the opening. The vortical motion is modeled in the potential flow framework, in which the oscillating motion of the thin shear layer is described by an array of convected point vortices, and the unsteady vortex shedding is determined by the Kutta condition. The cavity acoustic mode is obtained from the one-dimensional acoustic propagation model, the time-domain equivalent of which is given by means of a broadband time-domain impedance model. The acoustic resistances due to radiation and viscous loss at the opening are also taken into account. The physical processes of the self-excited oscillations, at both resonance and off-resonance states, are simulated directly in the time domain. Results show that the shear layer exhibits a weak flapping motion at the off-resonance state, whereas it rolls up into large-scale vortex cores when resonances occur. Single and dual-vortex patterns are observed corresponding to the first and second hydrodynamic modes. The simulation also reveals different trajectories of the two vortices across the opening when the first and second hydrodynamic modes co-exist. The strong modulation of the shed vorticity by the acoustic feedback at the resonance state is demonstrated. The model overestimates the pressure pulsation amplitude by a factor 2, which is expected to be due to the turbulence of the flow which is not taken into account. The model neglects vortex shedding at the downstream and side edges of the cavity. This will also result in an overestimation of the pulsation amplitude.

  13. Laboratory Experiments for Exploring the Surface Plasmon Resonance

    ERIC Educational Resources Information Center

    Pluchery, Olivier; Vayron, Romain; Van, Kha-Man

    2011-01-01

    The surface plasmon wave is a surface wave confined at the interface between a dielectric and a metal. The excitation of the surface plasmon resonance (SPR) on a gold thin film is discussed within the Kretschmann configuration, where the coupling with the excitation light is achieved by means of a prism in total reflection. The electromagnetic…

  14. Laboratory Experiments for Exploring the Surface Plasmon Resonance

    ERIC Educational Resources Information Center

    Pluchery, Olivier; Vayron, Romain; Van, Kha-Man

    2011-01-01

    The surface plasmon wave is a surface wave confined at the interface between a dielectric and a metal. The excitation of the surface plasmon resonance (SPR) on a gold thin film is discussed within the Kretschmann configuration, where the coupling with the excitation light is achieved by means of a prism in total reflection. The electromagnetic

  15. Part I. Analyzing the distribution of gas law questions in chemistry textbooks. Part II. Chlorine-35 NQR spectra of group 1 and silver dichloromethanesulfonates

    NASA Astrophysics Data System (ADS)

    Gillette, Gabriel

    Part I. Two studies involving the gas law questions in eight high school and Advanced Placement/college chemistry textbooks were performed using loglinear analysis to look for associations among six variables. These variables included Bloom's Taxonomy (higher-order, lower-order), Book Type (high school, college), Question Format (multiple-choice, problem, short answer), Question Placement (in-chapter, end-of-chapter, test bank), Representation (macroscopic, microscopic, symbolic), and Arkansas Science Standard (conceptual, mathematical; gas laws, pressure conversion, stoichiometry). The first study, involving the conceptual gas law questions, found the Book Type and Question Placement variables had the biggest impact, each appearing in 5 of the 11 significant associations. The second study, involving the mathematical gas law questions, found the Question Placement had the biggest impact, appearing in 7 of the 11 significant associations, followed by Book Type and the Arkansas Science Standard variables, which appeared in 5 of the 11 significant associations. These studies showed that compared to the high school books, college books have fewer multiple-choice questions (compared to short-answer and problem questions), fewer in-chapter questions (compared to end-of-chapter and test bank questions), fewer questions in the chapters and more questions at the end of the chapters and fewer multiple-choice questions in and at the end of the books and more multiple-choice questions in the test banks. Part II. The dichloromethanesulfonate salts of several +1 charged cations, M+Cl2CHSO3 - (M = Li, Na, K, Rb Ag, Cs Tl) were synthesized and studied by 35Cl nuclear quadrupole resonance (NQR). Dichloromethanesulfonic acid was prepared by the methanolysis of dichloromethanesulfonyl chloride, which was neutralized with the metal carbonates to produce the corresponding metal dichloromethanesulfonate salts. This study completed the NQR investigation of the family of chloroacetates and chloromethanesulfonates of silver. The study suggests that the ability of organochlorine atoms to coordinate to silver ions decreases as the number of electron-withdrawing groups attached to carbon atom bound to the coordinating chlorine atom increases. The unusually large NQR spectral width found among M+Cl2CHCO2 - salts are not present among M+Cl2CHSO 3- salts and does not appear to be generally characteristic of the dichloromethyl family of salts.

  16. Mapping Molecular Orientation in Solids by Rotating-Frame NQR Techniques

    NASA Astrophysics Data System (ADS)

    Casanova, F.; Robert, H.; Pusiol, D.

    1998-07-01

    A multi-dimensional NQR technique to image both the spatial distribution of quadrupolar nuclei and the local orientation of the electric field gradient tensor at the quadrupole sites in solids is reported. The encoding procedure is based on the irradiation of the sample by a pulse sequence composed of spatially homogeneous and inhomogeneous radiofrequency fields. A method that encodes the spatial and orientation information in the amplitudes of the free-induction decay signals and a proper three-dimensional reconstruction procedure that yields the space-orientation-dependent NQR spectra are described. A two-dimensional variant allows rapid measurement of the spatially dependent orientation distribution of molecules, disregarding the spectroscopic information.

  17. NQR study of molecular dynamics in tetramethylammonium hydrogen bis(difluorochloroacetate)

    NASA Astrophysics Data System (ADS)

    Zdanowska-Fr a̢czek, Maria

    1995-07-01

    The effect of temperature on the 35Cl NQR spectra and the spin-lattice relaxation time T1Q has been studied in N(CH 3) 4H(ClF 2CCOO) 2. The NQR signal disappeared at a temperature of about 110 K. The T1Q of the chlorines is attributed to the sum of two contributions: the reorientation of the CClF 2 group and the modulation of the electric field gradient (EFG) produced by the motion of the N(CH 3) +4 cation. The activation energies were determined to be 21.2 and 10.7 kJ mol -1 for the CClF 2 and N(CH 3) +4 motion respectively.

  18. Modern Michelson-Morley experiment using cryogenic optical resonators.

    PubMed

    Müller, Holger; Herrmann, Sven; Braxmaier, Claus; Schiller, Stephan; Peters, Achim

    2003-07-11

    We report on a new test of Lorentz invariance performed by comparing the resonance frequencies of two orthogonal cryogenic optical resonators subject to Earth's rotation over approximately 1 yr. For a possible anisotropy of the speed of light c, we obtain Delta(theta)c/c(0)=(2.6+/-1.7)x10(-15). Within the Robertson-Mansouri-Sexl (RMS) test theory, this implies an isotropy violation parameter beta-delta-1 / 2=(-2.2+/-1.5)x10(-9), about 3 times lower than the best previous result. Within the general extension of the standard model of particle physics, we extract limits on seven parameters at accuracies down to 10(-15), improving the best previous result by about 2 orders of magnitude. PMID:12906465

  19. Hadronic resonance production measured by the ALICE experiment at LHC

    NASA Astrophysics Data System (ADS)

    Malaev, Mikhail

    2016-01-01

    Hadronic resonances are among the most interesting probes of the hot and dense matter created in Pb-Pb collisions. Due to their short lifetime, they are sensitive to the anticipated chiral symmetry restoration as well as to suppression and regeneration due to hadronic interactions in the final state. At intermediate and high transverse momenta the hadron resonances, which cover the range of masses between the light pions and heavier protons, contribute to the systematic study of the baryon anomaly and parton energy loss in the dense medium. Measurements in pp collisions are used as a reference for collision of heavier systems and contribute to precision tests of pQCD and of the currently available parameterizations of fragmentation functions. Studies in p-Pb collisions are important for the interpretation of heavy ion results as they allow the decoupling of the initial nuclear effects from hot matter final state effects.

  20. Quantum molecular resonance-assisted phonomicrosurgery: preliminary experience.

    PubMed

    Demirhan, Erhan; Çukurova, İbrahim; Arslan, İlker Burak; Ozkan, Elcin Tadihan; Mengi, Erdem; Yigitbasi, Orhan Gazi

    2015-01-01

    The objective of this study was to evaluate the use of quantum molecular resonance (QMR) energy in phonomicrosurgery. Quantum molecular resonance energy (QMRE) is an innovative technology that provides low temperature cutting and coagulation of tissues and causes minimal tissue damage during the procedure. Because of these features, this technology may offer new possibilities in phonomicrosurgery. Twelve patients with vocal fold polyps underwent QMR-assisted phonomicrosurgery. The patients were evaluated before and after surgery at 1 and 3 months postoperatively by using the voice handicap index, laryngeal stroboscopy rating, acoustic voice analysis, and perceptual voice evaluation. The subjects were also evaluated by a patient self-assessment questionnaire at 3 months postoperatively. All parameters significantly improved after QMR-assisted phonomicrosurgery (P < .05). All of the patients also subjectively improved by self-rating. These results suggest that QMRE is a safe and potentially promising treatment in phonomicrosurgery. Yet, further studies should be conducted to confirm these results. PMID:25214549

  1. Mutual effect of ligands in nitrido and nitroso complexes of osmium and ruthenium from NQR data

    SciTech Connect

    Kravchenko. E.A.; Burtsev, M.Yu.; Sinitsyn, M.N.; Svetlov, A.A.; Kokunov, Ya.V.; Buslaev, A.

    1987-11-01

    The purpose of this investigation was to study by NQR the spectral results of the mutual ligand effect in complex compounds having various types of short bonds. The authors obtained the /sup 35/Cl, /sup 81/Br, and /sup 127/I NQR spectra of a large number of halogen complexes of osmium and ruthenium having short Os=N and M in equilibrium NO bonds of the following types: R(OsNHal/sub 4/) (R = (Ph/sub 4/P)/sup +/, (Bu/sub 4/N)/sup +/; Hal = Cl/sup -/, Br/sup -/, I/sup -/), K/sub 2/(OsNCl/sub 5/), Rb/sub 2/(OsNBr/sub 5/), (NH/sub 4/)/sub 2/(OsNBr/sub 5/), K(OsNHal/sub 4/L) (Hal = Cl/sup -/, Br/sup -/; L = H/sub 2/O, CH/sub 3/CN), K/sub 2/(MNOHal/sub 5/) (M = Os, Ru; Hal = Cl/sup -/, Br/sup -/, I/sup -/). The experimental NQR values measured are connected by the Townes and Dailey theory with the chemical bond characteristics i, sigma, ..pi.., the degree of the ionic, the sigma-covalent, and the ..pi..-covalent natures respectively ( i + sigma + ..pi.. = 1).

  2. Isotope effect on the temperature dependence of the 35Cl NQR frequency in (NH4)2RuCl6

    NASA Astrophysics Data System (ADS)

    Kume, Yoshio; Amino, Daiki; Asaji, Tetsuo

    2013-07-01

    The 35Cl nuclear quadrupole resonance frequencies and spin-lattice relaxation times for (NH4)2RuCl6, (ND4)2RuCl6, (NH4)2SnCl6, and (ND4)2SnCl6 were measured in the temperature range 4.2-300 K. In these four compounds, it was confirmed that no phase transition occurs in the observed temperature range. At 4.2 K, discrepancies of the NQR frequency between non-deuterated and deuterated compounds, which are attributed to the difference in the spatial distributions of hydrogen (deuterium) atoms in the ground states of the rotational motion of ammonium ion, reached to 24 kHz and 23 kHz for the ruthenate compounds and the stannate compounds, respectively. The separation between the ground and the first excited states of the rotational motion of the ammonium ion was estimated to be 466 J mol-1 and 840 J mol-1 for (ND4)2RuCl6 and (NH4)2RuCl6, respectively, by least-square fitting calculations of temperature dependence of the NQR frequency. For (ND4)2SnCl6 and (NH4)2SnCl6, these quantities were estimated to be 501 J mol-1 and 1544 J mol-1, respectively. It was clarified that the T1 minimum, which has been observed for the stannate compounds at around 60 K as a feature of the temperature dependence, was dependent on a method of sample preparation. It is concluded that the minimum is not an essential character of the ammonium hexachlorostannate(IV) since the crystals prepared in strong acid condition to prevent a partial substitution of chlorine atoms by hydroxyl groups, did not show such T1 minimum.

  3. 35Cl nuclear quadrupole resonance study in 4,4'-dichlorobiphenyl sulphone: A possible incommensurate system

    NASA Astrophysics Data System (ADS)

    Pusiol, D. J.; Wolfenson, A. E.; Brunetti, A. H.

    1989-08-01

    Pulsed nuclear quadrupole resonance (NQR) has been used to get information about the nature of the molecular dynamics in two crystalline phases of 4,4'-dichlorobiphenyl sulphone. This work includes detailed experimental measurements of the NQR frequency, spin-lattice relaxation time, and line intensity temperature behavior in the range of temperature where a possible normal-to-incommensurate phase transition occurs. The experimental results show the existence of strong precursor effects to the normal-incommensurate phase transition within the range 185-140 K.

  4. Resonance Raman Spectroscopy of Beta-Carotene and Lycopene: A Physical Chemistry Experiment.

    ERIC Educational Resources Information Center

    Hoskins, L. C.

    1984-01-01

    Discusses the theory of resonance Raman (RR) spectroscopy as it applies to beta-carotene and lycopene pigments (found in tomatoes and carrots, respectively). Also discusses an experiment which demonstrates the theoretical principles involved. The experiment has been tested over a three-year period and has received excellent acceptance by physical…

  5. Resonance Raman Spectroscopy of Beta-Carotene and Lycopene: A Physical Chemistry Experiment.

    ERIC Educational Resources Information Center

    Hoskins, L. C.

    1984-01-01

    Discusses the theory of resonance Raman (RR) spectroscopy as it applies to beta-carotene and lycopene pigments (found in tomatoes and carrots, respectively). Also discusses an experiment which demonstrates the theoretical principles involved. The experiment has been tested over a three-year period and has received excellent acceptance by physical

  6. A resonance phenomenon observed in a swept frequency experiment on a mother-daughter ionospheric rocket

    NASA Technical Reports Server (NTRS)

    Folkestad, K.; Troim, J.

    1974-01-01

    The report presents observations obtained in a swept frequency experiment conducted in a mother-daughter rocket flight at auroral latitudes. The discussion is essentially restricted to the possible interpretation of the experimental signal structures noted at and in the vicinity of a resonance frequency where signal components apparently are generated by nonlinear mechanisms. Various resonance frequencies have been considered in attempts to identify this multichannel response frequency. It is concluded that of all the possibilities invoked, the best consistency is provided by identifying the frequency concerned with the cone resonance frequency demonstrated experimentally in the case of a laboratory plasma by Fisher and Gould (1971).

  7. Effect of the oxygen protonation on the electronic structure of urea in the solid state: A 14N NQR study

    NASA Astrophysics Data System (ADS)

    Murgich, Juan; Santana R., Magaly

    1981-04-01

    The 14N NQR frequencies of urea complexes with H2O2 (1:1), NH4Cl (1:1), oxalic (2:1), phosphoric (1:1), and nitric acid (1:1) at 77 °K are reported. The analysis of the NQR data indicates that the population of the N nonbonding orbital decreases and that the population of the s N-H and N-C bonds increases as the degree of protonation of the O atom of urea increases. These changes are consistent with a larger weight of structures like C = N+H2 as the protonation increases. The NQR results are in agreement with those obtained from a CNDO/2 calculation for the uronioum ion [Yu. A. Panteleev and A. A. Lipovskii, Zhu. Struk. Khim. 17, 2 (1976)].

  8. A no-tune no-match wideband probe for nuclear quadrupole resonance spectroscopy in the VHF range

    NASA Astrophysics Data System (ADS)

    Scharfetter, Hermann; Petrovic, Andreas; Eggenhofer, Heidi; Stollberger, Rudolf

    2014-12-01

    Nuclear quadrupole resonance (NQR) spectroscopy is a method for the characterization of chemical compounds containing so-called quadrupolar nuclei. Similar to nuclear magnetic resonance (NMR), the sample under investigation is irradiated with strong radiofrequency (RF) pulses, which stimulate the emission of weak RF signals from the quadrupolar nuclei. The signals are then amplified and Fourier transformed so as to obtain a spectrum. In principle, narrowband NQR spectra can be measured with NMR spectrometers. However, pure NQR signals require the absence of a static magnetic field and several special applications require the characterization of a substance over a large bandwidth, e.g. 50-100% of the central frequency, which is hardly possible with standard NMR equipment. Dedicated zero-field NQR equipment is not widespread and current concepts employ resonating probes which are tuned and matched over a wide range by using mechanical capacitors driven by stepper motors. While providing the highest signal to noise ratio (SNR) such probes are slow in operation and can only be operated from dedicated NMR consoles. We developed a low-cost NQR wideband probe without tuning and matching for applications in the very high frequency (VHF) range below 300 MHz. The probe coil was realized as part of a reactive network which approximates an exponential transmission line. The input reflection coefficient of the two developed prototype probe coils is ≤ 20 dB between 90-145 MHz and 74.5-99.5 MHz, respectively. Two wideband NQR spectra of published test substances were acquired with an SNR of better than 20 dB after sufficient averaging. The measured signals and the SNR correspond very well to the theoretically expected values and demonstrate the feasibility of the method. Because there is no need for tuning and matching, our probes can be operated easily from any available NMR console.

  9. Resonating with the ghost of a hand: A TMS experiment.

    PubMed

    Craighero, Laila; Jacono, Marco; Mele, Sonia

    2016-04-01

    An impressive body of literature in the past 20 years has revealed a possible role played by cortical motor areas in action perception. One question that has been of interest is whether these areas are selectively tuned to process the actions of biological agents. However, no experiments directly testing the effects of the main characteristics identifying a biological agent (physical appearance and movement kinematics) on corticospinal excitability (CS) are present in literature. To fill this gap, we delivered single-pulse transcranial magnetic stimulation to the primary motor cortex and we recorded motor evoked potentials from contralateral hand muscles during observation of point-light-displays stimuli representing a hand having lost its physical appearance (Experiment 1) and kinematics characteristics (Experiment 2). Results showed that physical appearance, natural kinematics, and the possibility to identify the action behind the stimulus are not necessary conditions to modulate CS excitability during stimuli observation. We propose that the involvement of the motor system can be mandatory whenever the perceived movement, executed by a human, by an animal or by an object, is recognized as reproducible in its final outcome (e.g., position in space, direction of movement, posture of a body part, to-be-produced sound, specific interaction with an object, etc.), and that the peculiar relationship existing between others' actions and the actions executed by the observer could just represent the extreme in which the motor system is able to almost perfectly reproduce the observed stimulus as it unfolds and, consequently, contribute to stimulus perception in the most efficient way. PMID:26902157

  10. Resonant scattering experiments with radioactive nuclear beams - Recent results and future plans

    SciTech Connect

    Teranishi, T.; Sakaguchi, S.; Uesaka, T.; Kubono, S.; Wakabayashi, Y.; Yamaguchi, H.; Kurihara, Y.; Bihn, D. N.; Kahl, D.; Watanabe, S.; Hashimoto, T.; Hayakawa, S.; Khiem, L. H.; Cuong, P. V.; Goto, A.

    2013-04-19

    Resonant scattering with low-energy radioactive nuclear beams of E < 5 MeV/u have been studied at CRIB of CNS and at RIPS of RIKEN. As an extension to the present experimental technique, we will install an advanced polarized proton target for resonant scattering experiments. A Monte-Carlo simulation was performed to study the feasibility of future experiments with the polarized target. In the Monte-Carlo simulation, excitation functions and analyzing powers were calculated using a newly developed R-matrix calculation code. A project of a small-scale radioactive beam facility at Kyushu University is also briefly described.

  11. Two-Dimensional Rotating-Frame NQR Imaging

    NASA Astrophysics Data System (ADS)

    Robert, H.; Pusiol, D.

    1997-07-01

    A new technique for two-dimensional rotating-frame nuclear-quadrupole-resonance imaging in powder or polycrystalline samples is reported. The bidimensional encoding procedure is based on the irradiation of the object by a sequence of pulsed orthogonal radiofrequency linear gradients. The spatial-density function, together with the spectroscopic information, is directly recorded in Cartesian coordinates. Several variants of the encoding procedure are discussed, and experimental results demonstrating the viability of the technique are given.

  12. External resonator tunable diode laser (TDL) system for extracavity and intracavity absorption: Experiments and modeling

    SciTech Connect

    Gurlit, W.; Trentmann, J.; Burrows, J.P.; Burkhard, H.

    1996-12-31

    A 1,530 nm multimode laser with an external resonator containing a grating achieved a single-mode tuning range of 100 nm. Etalon effects and modehops during the frequency tuning of the laser were minimized by special design features. Absorptions of water vapor were recorded intracavity and extracavity. The intracavity experiments were impeded by modehops induced by the absorption itself. This effect could be reduced by increasing the selectivity of the resonator. Modeling of the optical properties of the resonator allows the quantitative specification of the optical parameters for a singlemode intracavity tunable diode laser (TDL) operation. This enables a resonator design to be realized which achieves an optimum stability and selectivity for a singlemode TDL for both extracavity and intracavity applications.

  13. 35CI NQR Spectroscopy on Salts and Molecular Compounds of Trichloroacetic Acid

    NASA Astrophysics Data System (ADS)

    Fichtner, Winfried; Markworth, Axel; Weiden, Norbert; Weiss, Alarich

    1986-02-01

    The temperature dependence of salts M(1)H(Cl3CCOO)2 and molecular compounds of trichloroacetic acid with amines and benzaldehydes, TCA · X, was studied, The data fit rather well to the known dependence of the mean frequency shift Δ on the pkadifference of X with respect to TCA. A linear relation is observed between the bleaching out temperature Tb of the 35Cl NQR lines and Δ for M(1)H(Cl3CCOO)2 and for TCA · X, X = benzaldehydes.

  14. Time-delayed feedback control of coherence resonance near subcritical Hopf bifurcation: Theory versus experiment

    NASA Astrophysics Data System (ADS)

    Semenov, Vladimir; Feoktistov, Alexey; Vadivasova, Tatyana; Schll, Eckehard; Zakharova, Anna

    2015-03-01

    Using the model of a generalized Van der Pol oscillator in the regime of subcritical Hopf bifurcation, we investigate the influence of time delay on noise-induced oscillations. It is shown that for appropriate choices of time delay, either suppression or enhancement of coherence resonance can be achieved. Analytical calculations are combined with numerical simulations and experiments on an electronic circuit.

  15. Time-delayed feedback control of coherence resonance near subcritical Hopf bifurcation: theory versus experiment.

    PubMed

    Semenov, Vladimir; Feoktistov, Alexey; Vadivasova, Tatyana; Schöll, Eckehard; Zakharova, Anna

    2015-03-01

    Using the model of a generalized Van der Pol oscillator in the regime of subcritical Hopf bifurcation, we investigate the influence of time delay on noise-induced oscillations. It is shown that for appropriate choices of time delay, either suppression or enhancement of coherence resonance can be achieved. Analytical calculations are combined with numerical simulations and experiments on an electronic circuit. PMID:25833433

  16. Time-delayed feedback control of coherence resonance near subcritical Hopf bifurcation: Theory versus experiment

    SciTech Connect

    Semenov, Vladimir; Feoktistov, Alexey; Vadivasova, Tatyana; Schöll, Eckehard Zakharova, Anna

    2015-03-15

    Using the model of a generalized Van der Pol oscillator in the regime of subcritical Hopf bifurcation, we investigate the influence of time delay on noise-induced oscillations. It is shown that for appropriate choices of time delay, either suppression or enhancement of coherence resonance can be achieved. Analytical calculations are combined with numerical simulations and experiments on an electronic circuit.

  17. Nitrogen and deuterium nuclear quadrupole resonance in lanthanum nicotinate dihydrate

    NASA Astrophysics Data System (ADS)

    Davidson, M. M.; Edmonds, D. T.; Mailer, J. P. G.

    1981-01-01

    Using nuclear double quadrupole resonance techniques the nuclear quadrupole resonance (NQR) spectra of the three inequivalent 14N sites and the four water 2D sites have been obtained at 77 K for lanthanum nicotinate dihydrate. The quadrupole coupling constants e2qQ/h in kHz and the anisotropy constant η are for nitrogen 4418 and 0.362, 4222 and 0.335, and 4220 and 0.327. For the deuterons they are 233.73 and 0.080, 177.47 and 0.153 for one water molecule and 219.73 and 0.098, 189.07 and 0.148 for the other. An attempt is made to extract structural data from these NQR results.

  18. Are magnetic resonances practical transport controllers in fusion plasmas? The TJ-II experience

    NASA Astrophysics Data System (ADS)

    Lpez-Bruna, D.; Vargas, V. I.; Romero, J. A.

    2015-03-01

    The TJ-II stellarator is a mid-size Heliac design (high rotational transform, low magnetic shear) that allows for external control of the rotational transform profile. The long experience with locating diverse magnetic resonances at different plasma radii has assessed their reliability as transport controllers: in low density electron cyclotron heating plasmas, a transport barrier effect is found in most of the confinement zone accompanying magnetic resonances; in higher density and beta plasmas under neutral-beam heating operation, resonant layers show a clear incidence on the access to the H-mode of confinement or, likewise, on the back transition to L-mode. Moreover, confinement events similar to tokamak phenomenology have been also related with magneto-hydrodynamic activity around the magnetic resonances and are, consequently, amenable to external control. All in all, the TJ-II experience posits magnetic resonances as natural transport and stability controllers in toroidal plasmas. Further studies must either confirm or set operational limits to these findings.

  19. Cu NQR study of charge localization in HgBa2CuO4+? with different oxygen content

    NASA Astrophysics Data System (ADS)

    Gippius, A. A.; Antipov, E. V.; Hoffmann, W.; Lders, K.

    1996-02-01

    Variation of the oxygen content ? in HgBa2CuO4+?(1201) provides a good opportunity to study the influence of oxygen doping on nuclear quadrupole interactions (NQI) and charge localization in different regions of (Tc-?) phase diagram. We performed63,65Cu NQR of series HgBa2CuO4+? samples with different oxygen content ?.

  20. 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 η = 0.84±.04; 7Li in lithium acetylacetonate for which the spectrum (corrected for Zeeman distortion) yields e2Qq/h = (152 ±5) kHz and η=.5 ±.2. Calculated spectra are presented to demonstrate the η dependence of the line shapes for 7Li.

  1. 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 с up to the values of 500 kg/сm2 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.

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

    SciTech Connect

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

    2010-09-01

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

  3. A 15N CPMG relaxation dispersion experiment more resistant to resonance offset and pulse imperfection

    NASA Astrophysics Data System (ADS)

    Jiang, Bin; Yu, Binhan; Zhang, Xu; Liu, Maili; Yang, Daiwen

    2015-08-01

    Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion is a powerful NMR method to study protein dynamics on the microsecond-millisecond time scale. J-coupling, resonance offset, radio frequency field inhomogeneity, and pulse imperfection often introduce systematic errors into the measured transverse relaxation rates. Here we proposed a modified continuous wave decoupling CPMG experiment, which is more unaffected by resonance offset and pulse imperfection. We found that it is unnecessary to match the decoupling field strength with the delay between CPMG refocusing pulses, provided that decoupling field is strong enough. The performance of the scheme proposed here was shown by simulations and further demonstrated experimentally on a fatty acid binding protein.

  4. Results of Resonant Activation and Macroscopic Quantum Tunneling Experiments in Magnesium Diboride Thin Film Josephson Junctions

    NASA Astrophysics Data System (ADS)

    Ramos, Roberto; Carabello, Steve; Lambert, Joseph; Mlack, Jerome; Dai, Wenqing; Shen, Yi.; Li, Qi; Cunnane, Daniel; Zhuang, C. G.; Chen, Ke; Xi, X. X.

    2012-02-01

    The Josephson junction is an experimental testbed widely used to study resonant activation and macroscopic quantum tunneling. These phenomena have been observed in junctions based on conventional low-temperature superconductors such as Nb and Al, and even in high-Tc, intrinsic superconductors. We report results of superconducting-to normal state switching experiments below 1 K using MgB2-based Josephson heterojunctions with Pb and Nb counter-electrodes. Measurements were made with and without RF excitation. With microwaves, we see evidence of a resonant peak, in addition to the primary escape (from ground state) peak -- consistent with resonant activation. We also observe features suggestive of macroscopic quantum tunneling including peaks in the escape rate enhancements and an ``elbow'' in the graph of calculated escape temperatures Tesc versus sample temperature.

  5. Two-photon finite-pulse model for resonant transitions in attosecond experiments

    NASA Astrophysics Data System (ADS)

    Jiménez-Galán, Álvaro; Martín, Fernando; Argenti, Luca

    2016-02-01

    We present an analytical model capable of describing two-photon ionization of atoms with attosecond pulses in the presence of intermediate and final isolated autoionizing states. The model is based on the finite-pulse formulation of second-order time-dependent perturbation theory. It approximates the intermediate and final states with Fano's theory for resonant continua, and it depends on a small set of atomic parameters that can either be obtained from separate ab initio calculations or be extracted from a few selected experiments. We use the model to compute the two-photon resonant photoelectron spectrum of helium below the N =2 threshold for the RABITT (reconstruction of attosecond beating by interference of two-photon transitions) pump-probe scheme, in which an XUV attosecond pulse train is used in association with a weak IR probe, obtaining results in quantitative agreement with those from accurate ab initio simulations. In particular, we show that (i) the use of finite pulses results in a homogeneous redshift of the RABITT beating frequency, as well as a resonant modulation of the beating frequency in proximity to intermediate autoionizing states; (ii) the phase of resonant two-photon amplitudes generally experiences a continuous excursion as a function of the intermediate detuning, with either zero or 2 π overall variation.

  6. Instrument for in-situ orientation of superconducting thin-film resonators used for electron-spin resonance experiments

    SciTech Connect

    Mowry, Andrew; Kubasek, James; Friedman, Jonathan R.; Chen, Yiming

    2015-01-15

    When used in electron-spin resonance measurements, superconducting thin-film resonators must be precisely oriented relative to the external magnetic field in order to prevent the trapping of magnetic flux and the associated degradation of resonator performance. We present a compact design solution for this problem that allows in-situ control of the orientation of the resonator at cryogenic temperatures. Tests of the apparatus show that when proper alignment is achieved, there is almost no hysteresis in the field dependence of the resonant frequency.

  7. Variable-Pitch Rectangular Cross-section Radiofrequency Coils for the Nitrogen-14 Nuclear Quadrupole Resonance Investigation of Sealed Medicines Packets

    PubMed Central

    2012-01-01

    The performance of rectangular radio frequency (RF) coils capable of being used to detect nuclear quadrupole resonance (NQR) signals from blister packs of medicines has been compared. The performance of a fixed-pitch RF coil was compared with that from two variable-pitch coils, one based on a design in the literature and the other optimized to obtain the most homogeneous RF field over the whole volume of the coil. It has been shown from 14N NQR measurements with two medicines, the antibiotic ampicillin (as trihydrate) and the analgesic medicine Paracetamol, that the latter design gives NQR signal intensities almost independent of the distribution of the capsules or pills within the RF coil and is therefore more suitable for quantitative analysis. PMID:23057555

  8. MUSIC in triple-resonance experiments: amino acid type-selective (1)H-(15)N correlations

    PubMed

    Schubert; Smalla; Schmieder; Oschkinat

    1999-11-01

    Amino acid type-selective triple-resonance experiments can be of great help for the assignment of protein spectra, since they help to remove ambiguities in either manual or automated assignment procedures. Here, modified triple-resonance experiments that yield amino acid type-selective (1)H-(15)N correlations are presented. They are based on novel coherence transfer schemes, the MUSIC pulse sequence elements, that replace the initial INEPT transfer and are selective for XH(2) or XH(3) (X can be (15)N or (13)C). The desired amino acid type is thereby selected based on the topology of the side chain. Experiments for Gly (G-HSQC); Ala (A-HSQC); Thr, Val, Ile, and Ala (TAVI-HSQC); Thr and Ala (TA-HSQC), as well as Asn and Gln (N-HSQC and QN-HSQC), are described. The new experiments are recorded as two-dimensional experiments and therefore need only small amounts of spectrometer time. The performance of the experiments is demonstrated with the application to two protein domains. Copyright 1999 Academic Press. PMID:10527741

  9. MUSIC in Triple-Resonance Experiments: Amino Acid Type-Selective 1H- 15N Correlations

    NASA Astrophysics Data System (ADS)

    Schubert, Mario; Smalla, Maika; Schmieder, Peter; Oschkinat, Hartmut

    1999-11-01

    Amino acid type-selective triple-resonance experiments can be of great help for the assignment of protein spectra, since they help to remove ambiguities in either manual or automated assignment procedures. Here, modified triple-resonance experiments that yield amino acid type-selective 1H-15N correlations are presented. They are based on novel coherence transfer schemes, the MUSIC pulse sequence elements, that replace the initial INEPT transfer and are selective for XH2 or XH3 (X can be 15N or 13C). The desired amino acid type is thereby selected based on the topology of the side chain. Experiments for Gly (G-HSQC); Ala (A-HSQC); Thr, Val, Ile, and Ala (TAVI-HSQC); Thr and Ala (TA-HSQC), as well as Asn and Gln (N-HSQC and QN-HSQC), are described. The new experiments are recorded as two-dimensional experiments and therefore need only small amounts of spectrometer time. The performance of the experiments is demonstrated with the application to two protein domains.

  10. Low Threshold Parametric Decay Backscattering Instability in Tokamak Electron Cyclotron Resonance Heating Experiments

    SciTech Connect

    Gusakov, E. Z.; Popov, A. Yu.

    2010-09-10

    The experimental conditions leading to substantial reduction of the backscattering decay instability threshold in electron cyclotron resonance heating experiments in toroidal devices are analyzed. It is shown that a drastic decrease of threshold is provided by the nonmonotonic behavior of plasma density in the vicinity of magnetic island and poloidal magnetic field inhomogeneity making possible localization of ion Bernstein decay waves. The corresponding ion Bernstein wave gain and the parametric decay instability pump power threshold is calculated.

  11. a Modern Michelson-Morley Experiment Using Actively Rotated Optical Resonators

    NASA Astrophysics Data System (ADS)

    Herrmann, S.; Senger, A.; Möhle, K.; Kovalchuk, E. V.; Peters, A.

    2008-03-01

    We present a new setup of a Michelson-Morley test of the isotropy of the speed of light that achieves an order of magnitude improvement in sensitivity as compared to previous measurements. The experiment compares the resonance frequencies of two orthogonal cavities, implemented in a single block of fused silica and rotated on an air bearing turntable once every 45 s. A preliminary analysis of first data already provides limits on combinations of SME parameters at the level of 10-17.

  12. Anomalous echo: Exploring abnormal experience correlates of emotional motor resonance in Schizophrenia Spectrum.

    PubMed

    Sestito, Mariateresa; Raballo, Andrea; Umiltà, Maria Alessandra; Amore, Mario; Maggini, Carlo; Gallese, Vittorio

    2015-09-30

    Anomalous experiences such as Basic Symptoms (BS) are considered the first subjective manifestation of the neurobiological substrate of schizophrenia. The purpose of this study was to explore whether a low or high emotional motor resonance occurring in Schizophrenia Spectrum (SzSp) patients was related to patients׳ clinical features and to their anomalous subjective experiences as indexed by the Bonn Scale for the Assessment of Basic Symptoms (BSABS). To this aim, we employed a validated paradigm sensitive in evoking a congruent facial mimicry (measured by means of facial electromyographic activity, EMG) through multimodal positive and negative emotional stimuli presentation. Results showed that SzSp patients more resonating with negative emotional stimuli (i.e. Externalizers) had significantly higher scores in BSABS Cluster 3 (Vulnerability) and more psychotic episodes than Internalizers patients. On the other hand, SzSp patients more resonating with positive emotional stimuli (i.e. Externalizers) scored higher in BSABS Cluster 5 (Interpersonal irritation) than Internalizers. Drawing upon a phenomenological-based perspective, we attempted to shed new light on the abnormal experiences characterizing schizophrenia, explaining them in terms of a disruption of the normal self-perception conveyed by the basic, low-level emotional motor mechanisms. PMID:26187341

  13. Circular waveguide systems for electron-cyclotron-resonant heating of the tandem mirror experiment-upgrade

    SciTech Connect

    Felker, B.; Calderon, M.O.; Chargin, A.K.; Coffield, F.E.; Gallagher, N.C. Jr.; Lang, D.D.; Pedrotti, L.R.; Rubert, R.R.; Stallard, B.W.; Sweeney, D.W.

    1983-11-18

    Extensive use of electron cyclotron resonant heating (ECRH) in the Tandem Mirror Experiment-Upgrade (TMX-U) requires continuous development of components to improve efficiency, increase reliability, and deliver power to new locations with respect to the plasma. We have used rectangular waveguide components on the experiment and have developed, tested, and installed circular waveguide components. We replaced the rectangular with the circular components because of the greater transmission efficiency and power-handling capability of the circular ones. Design, fabrication, and testing of all components are complete for all systems. In this paper we describe the design criteria for the system.

  14. 35Cl NQR Study of Thermoactivated Motions of Nitro Groups in Picryl Chloride

    NASA Astrophysics Data System (ADS)

    Kyuntsel, Igor A.

    1996-06-01

    The temperature dependences of the 35Cl NQR frequency (ν), spin-lattice relaxation time (T1), and spin-spin relaxation time (T2) have been studied in 2,4,6-trinitrochlorobenzene (picryl chloride) from 77 K up to the melting point (354 K). The T1(T) curve exhibits a pronounced composite mimimum near 300 K which gives evidence for the reorientations of the two ortho-NO2 groups around their two-fold symmetry axes with the activation energies of 27.4 kJ mol - 1 and 31.2 kJ mol - 1. These values can be related to the ortho-NO2 groups having the twist angles of 33° and 81°, respectively (the crystal structure of picryl chloride is known). The T2(T) dependence exhibits interesting features, too: a deep minimum about 140 K and a new rapid decrease above 270 K.

  15. Experiment and simulation of hole-coupled resonator modes with a CW HeNe laser

    SciTech Connect

    Leemans, W.P.; Xie, M.; Edighoffer, J.A.; Wallace, E.; Kim, K.J.; Chattopadhyay, S.

    1992-08-01

    The Infrared Free Electron Laser (IRFEL) for the proposed Chemical Dynamics Laboratory at Lawrence Berkeley Laboratory will operate from 3 - 50 [mu]m and use all-metal optics. This choice of optics allows for broad tuning and has excellent power-handling capabilities. A hole-coupling approach for the optical resonator was adopted after extensive computer simulations verified that it fully met the design requirements. To bench-test the simulations we have carried out a scaled cavity experiment utilizing a visible (632.8 nm) continuous wave (CW) HeNe laser. Two cases have been studied: (a) a Gaussian near-concentric symmetric resonator and (b) a hole-coupled resonator with degenerate higher order modes. The simple geometry of the former case allows for a direct comparison with analytical theory and is useful for bench marking the diagnostic equipment. Since mode degeneracy should be avoided for good operation of an FEL, gaining an understanding of the latter case is important. Furthermore, it provides a good test case for evaluating the code performance. After discussing the theoretical model used in the simulations, we describe the cavity parameters and the experimental set-up. We proceed by comparing, for both case (a) and (b), the experimental results with theoretical predictions and simulations. This is followed by the summary and conclusions of these experiments.

  16. Experiment and simulation of hole-coupled resonator modes with a CW HeNe laser

    SciTech Connect

    Leemans, W.P.; Xie, M.; Edighoffer, J.A.; Wallace, E.; Kim, K.J.; Chattopadhyay, S.

    1992-08-01

    The Infrared Free Electron Laser (IRFEL) for the proposed Chemical Dynamics Laboratory at Lawrence Berkeley Laboratory will operate from 3 - 50 {mu}m and use all-metal optics. This choice of optics allows for broad tuning and has excellent power-handling capabilities. A hole-coupling approach for the optical resonator was adopted after extensive computer simulations verified that it fully met the design requirements. To bench-test the simulations we have carried out a scaled cavity experiment utilizing a visible (632.8 nm) continuous wave (CW) HeNe laser. Two cases have been studied: (a) a Gaussian near-concentric symmetric resonator and (b) a hole-coupled resonator with degenerate higher order modes. The simple geometry of the former case allows for a direct comparison with analytical theory and is useful for bench marking the diagnostic equipment. Since mode degeneracy should be avoided for good operation of an FEL, gaining an understanding of the latter case is important. Furthermore, it provides a good test case for evaluating the code performance. After discussing the theoretical model used in the simulations, we describe the cavity parameters and the experimental set-up. We proceed by comparing, for both case (a) and (b), the experimental results with theoretical predictions and simulations. This is followed by the summary and conclusions of these experiments.

  17. Nuclear Quadrupole Resonance in the Heavy Fermion Antiferromagnet CePt2In7

    NASA Astrophysics Data System (ADS)

    apRoberts-Warren, N.; Dioguardi, A. P.; Shockley, A. C.; Lin, C. H.; Crocker, J.; Klavins, P.; Curro, N. J.

    2012-03-01

    New 115In NQR data is presented for the 9/2 leftrightarrow 7/2 of the In(2) site transition in the heavy fermion compound CePt2In7. We extract the sub-lattice magnetization in the antiferromagnetic state. The spectra reveal that roughly half of the In(2) sites experience no static hyperfine field.

  18. Dynamic field-frequency lock for tracking magnetic field fluctuations in electron spin resonance experiments

    NASA Astrophysics Data System (ADS)

    Asfaw, Abraham; Tyryshkin, Alexei; Lyon, Stephen

    Global magnetic field fluctuations present significant challenges to pulsed electron spin resonance experiments on systems with long spin coherence times. We will discuss results from experiments in which we follow instantaneous changes in magnetic field by locking to the free induction decay of a proton NMR signal using a phase-locked loop. We extend conventional field-frequency locking techniques used in NMR to follow slow magnetic field drifts by using a modified Carr-Purcell-Meiboom-Gill (CPMG) pulse sequence in which the phase of the pi-pulses follows the phase of the proton spins at all times. Hence, we retain the ability of the CPMG pulse sequence to refocus local magnetic field inhomogeneities without refocusing global magnetic field fluctuations. In contrast with conventional field-frequency locking techniques, our experiments demonstrate the potential of this method to dynamically track global magnetic field fluctuations on timescales of about 2 seconds and with rates faster than a kHz. This frequency range covers the dominant noise frequencies in our electron spin resonance experiments as previously reported.

  19. A mechanical analog of the two-bounce resonance of solitary waves: Modeling and experiment.

    PubMed

    Goodman, Roy H; Rahman, Aminur; Bellanich, Michael J; Morrison, Catherine N

    2015-04-01

    We describe a simple mechanical system, a ball rolling along a specially-designed landscape, which mimics the well-known two-bounce resonance in solitary wave collisions, a phenomenon that has been seen in countless numerical simulations but never in the laboratory. We provide a brief history of the solitary wave problem, stressing the fundamental role collective-coordinate models played in understanding this phenomenon. We derive the equations governing the motion of a point particle confined to such a surface and then design a surface on which to roll the ball, such that its motion will evolve under the same equations that approximately govern solitary wave collisions. We report on physical experiments, carried out in an undergraduate applied mathematics course, that seem to exhibit the two-bounce resonance. PMID:25933657

  20. A mechanical analog of the two-bounce resonance of solitary waves: Modeling and experiment

    NASA Astrophysics Data System (ADS)

    Goodman, Roy H.; Rahman, Aminur; Bellanich, Michael J.; Morrison, Catherine N.

    2015-04-01

    We describe a simple mechanical system, a ball rolling along a specially-designed landscape, which mimics the well-known two-bounce resonance in solitary wave collisions, a phenomenon that has been seen in countless numerical simulations but never in the laboratory. We provide a brief history of the solitary wave problem, stressing the fundamental role collective-coordinate models played in understanding this phenomenon. We derive the equations governing the motion of a point particle confined to such a surface and then design a surface on which to roll the ball, such that its motion will evolve under the same equations that approximately govern solitary wave collisions. We report on physical experiments, carried out in an undergraduate applied mathematics course, that seem to exhibit the two-bounce resonance.

  1. 35Cl NQR and 1H NMR Studies of Molecular Motions in Guanidinium Salt of Chloroacetic Acid

    NASA Astrophysics Data System (ADS)

    Zdanowska-Fnjczek, Maria; Grottel, Małgorzata; Jakubas, Ryszard

    1998-07-01

    Multinuclear NQR and NMR techniques have been applied in order to study the molecular dynamics in [C(NH2)3](ClH2CCOO). The 35Cl NQR frequency was measured over a wide range of temperature. The experimental results were described by using the theories of Bayer and Brown which take into account the torsional oscillations of the CClH2 -group of the anion. A study of the proton NMR second moment as well as relaxation times T1, and T1p performed in a wide temperature range revealed an onset of the guanidinium cation reorientation around its two-fold symmetry axis. Activation parameters for this motion were determined.

  2. 55Mn NQR Study at Mn-II Sites in β-Mn Metal: A Possible Effect of Geometrical Frustration

    NASA Astrophysics Data System (ADS)

    Hama, Tetsuya; Matsumura, Masahiro; Kato, Harukazu; Yamagata, Hideki; Kohori, Yoh; Kohara, Takao; Iwamoto, Yuji

    2004-08-01

    55Mn NQR measurements at the Mn-II site in a polycrystalline β-Mn have been performed over the wide temperature range up to 300 K. Fine structures in the NQR spectrum are newly observed below 100 K, indicating that a sufficiently large region of the sample has an antiferromagnetic moment with a small magnitude of ˜ 10-4 μB. Taking account of the fact that the spectral shape depends on the sample particle size, we suggest that the surfaces of the sample particles affect the electronic ground state of β-Mn and that the staggered moment extends within 3 μm depth from the surface. A role of the geometrical frustration is discussed. The nuclear spin-lattice relaxation rate 1/T1 and the spin-spin relaxation rate 1/T2 increase divergently at high temperatures, implying quadrupole relaxation arising from lattice vibrations.

  3. Solid-state NMR/NQR and first-principles study of two niobium halide cluster compounds.

    PubMed

    Perić, Berislav; Gautier, Régis; Pickard, Chris J; Bosiočić, Marko; Grbić, Mihael S; Požek, Miroslav

    2014-01-01

    Two hexanuclear niobium halide cluster compounds with a [Nb6X12](2+) (X=Cl, Br) diamagnetic cluster core, have been studied by a combination of experimental solid-state NMR/NQR techniques and PAW/GIPAW calculations. For niobium sites the NMR parameters were determined by using variable Bo field static broadband NMR measurements and additional NQR measurements. It was found that they possess large positive chemical shifts, contrary to majority of niobium compounds studied so far by solid-state NMR, but in accordance with chemical shifts of (95)Mo nuclei in structurally related compounds containing [Mo6Br8](4+) cluster cores. Experimentally determined δiso((93)Nb) values are in the range from 2,400 to 3,000 ppm. A detailed analysis of geometrical relations between computed electric field gradient (EFG) and chemical shift (CS) tensors with respect to structural features of cluster units was carried out. These tensors on niobium sites are almost axially symmetric with parallel orientation of the largest EFG and the smallest CS principal axes (Vzz and δ33) coinciding with the molecular four-fold axis of the [Nb6X12](2+) unit. Bridging halogen sites are characterized by large asymmetry of EFG and CS tensors, the largest EFG principal axis (Vzz) is perpendicular to the X-Nb bonds, while intermediate EFG principal axis (Vyy) and the largest CS principal axis (δ11) are oriented in the radial direction with respect to the center of the cluster unit. For more symmetrical bromide compound the PAW predictions for EFG parameters are in better correspondence with the NMR/NQR measurements than in the less symmetrical chlorine compound. Theoretically predicted NMR parameters of bridging halogen sites were checked by (79/81)Br NQR and (35)Cl solid-state NMR measurements. PMID:24581866

  4. Structural and functional investigation of flavin binding center of the NqrC subunit of sodium-translocating NADH:quinone oxidoreductase from Vibrio harveyi.

    PubMed

    Borshchevskiy, Valentin; Round, Ekaterina; Bertsova, Yulia; Polovinkin, Vitaly; Gushchin, Ivan; Ishchenko, Andrii; Kovalev, Kirill; Mishin, Alexey; Kachalova, Galina; Popov, Alexander; Bogachev, Alexander; Gordeliy, Valentin

    2015-01-01

    Na+-translocating NADH:quinone oxidoreductase (NQR) is a redox-driven sodium pump operating in the respiratory chain of various bacteria, including pathogenic species. The enzyme has a unique set of redox active prosthetic groups, which includes two covalently bound flavin mononucleotide (FMN) residues attached to threonine residues in subunits NqrB and NqrC. The reason of FMN covalent bonding in the subunits has not been established yet. In the current work, binding of free FMN to the apo-form of NqrC from Vibrio harveyi was studied showing very low affinity of NqrC to FMN in the absence of its covalent bonding. To study structural aspects of flavin binding in NqrC, its holo-form was crystallized and its 3D structure was solved at 1.56 Å resolution. It was found that the isoalloxazine moiety of the FMN residue is buried in a hydrophobic cavity and that its pyrimidine ring is squeezed between hydrophobic amino acid residues while its benzene ring is extended from the protein surroundings. This structure of the flavin-binding pocket appears to provide flexibility of the benzene ring, which can help the FMN residue to take the bended conformation and thus to stabilize the one-electron reduced form of the prosthetic group. These properties may also lead to relatively weak noncovalent binding of the flavin. This fact along with periplasmic location of the FMN-binding domains in the vast majority of NqrC-like proteins may explain the necessity of the covalent bonding of this prosthetic group to prevent its loss to the external medium. PMID:25734798

  5. Structural and Functional Investigation of Flavin Binding Center of the NqrC Subunit of Sodium-Translocating NADH:Quinone Oxidoreductase from Vibrio harveyi

    PubMed Central

    Bertsova, Yulia; Polovinkin, Vitaly; Gushchin, Ivan; Ishchenko, Andrii; Kovalev, Kirill; Mishin, Alexey; Kachalova, Galina; Popov, Alexander; Bogachev, Alexander; Gordeliy, Valentin

    2015-01-01

    Na+-translocating NADH:quinone oxidoreductase (NQR) is a redox-driven sodium pump operating in the respiratory chain of various bacteria, including pathogenic species. The enzyme has a unique set of redox active prosthetic groups, which includes two covalently bound flavin mononucleotide (FMN) residues attached to threonine residues in subunits NqrB and NqrC. The reason of FMN covalent bonding in the subunits has not been established yet. In the current work, binding of free FMN to the apo-form of NqrC from Vibrio harveyi was studied showing very low affinity of NqrC to FMN in the absence of its covalent bonding. To study structural aspects of flavin binding in NqrC, its holo-form was crystallized and its 3D structure was solved at 1.56 Å resolution. It was found that the isoalloxazine moiety of the FMN residue is buried in a hydrophobic cavity and that its pyrimidine ring is squeezed between hydrophobic amino acid residues while its benzene ring is extended from the protein surroundings. This structure of the flavin-binding pocket appears to provide flexibility of the benzene ring, which can help the FMN residue to take the bended conformation and thus to stabilize the one-electron reduced form of the prosthetic group. These properties may also lead to relatively weak noncovalent binding of the flavin. This fact along with periplasmic location of the FMN-binding domains in the vast majority of NqrC-like proteins may explain the necessity of the covalent bonding of this prosthetic group to prevent its loss to the external medium. PMID:25734798

  6. 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. ); Schirber, J.E. )

    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.

  7. 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.; Ziegeweid, M.; Pines, A. |

    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.

  8. M dependence in the analysis of NH3-He microwave double resonance experiments

    NASA Technical Reports Server (NTRS)

    Davis, S. L.; Green, S.

    1983-01-01

    New close-coupled calculations of laboratory-frame, m-dependent cross sections for rotational excitation in NH3-He collisions are used to examined the validity of using degeneracy averaged values in the analysis of four-level double resonance experiments. It is found that the proper use of m-dependent cross sections and absorption probabilities produces only minor changes in the calculated Delta I/I (the fractional change in the signal absorption intensity when pumping radiation is applied) and does not, therefore, resolve the discrepancies between theoretical and experimental values that were noted in previous studies.

  9. Determination of the Defining Boundary in Nuclear Magnetic Resonance Diffusion Experiments

    NASA Astrophysics Data System (ADS)

    Laun, Frederik Bernd; Kuder, Tristan Anselm; Semmler, Wolfhard; Stieltjes, Bram

    2011-07-01

    While nuclear magnetic resonance diffusion experiments are widely used to resolve structures confining the diffusion process, it has been elusive whether they can exactly reveal these structures. This question is closely related to x-ray scattering and to Kac’s “hear the drum” problem. Although the shape of the drum is not “hearable,” we show that the confining boundary of closed pores can indeed be detected using modified Stejskal-Tanner magnetic field gradients that preserve the phase information and enable imaging of the average pore in a porous medium with a largely increased signal-to-noise ratio.

  10. DC SQUID detection of new magnetic resonance phenomena

    SciTech Connect

    Sleator, T.

    1986-01-01

    A dc Superconducting QUantum Interference Device (SQUID) was used as a tuned radio-frequency amplifier at liquid helium temperatures to detect very-low-signal magnetic resonance phenomena. Three experiments were performed. In the first experiment, a dc SQUID was used to detect pulsed nuclear quadrupole resonance at about 30 MHz. At a bath temperature of 4.2K, a total system noise temperature of 6 +/- 1K was achieved, with a quality factor Q of 2500. A novel Q-spoiler, consisting of a series array of Josephson tunnel junction, reduced the ring-down time of the tuned circuit after each pulse. The minimum number of nuclear Bohr magnetons observable from a free-precession signal after a single pulse was about 2 x 10/sup 16/ in a bandwidth of 10 kHz. In the second experiment, a sample of nuclear spins was placed in the inductor of a tuned LCR circuit and the spectral density of current fluctuations in the circuit was measured using a dc SQUID as an rf amplifier. The measurements were made in liquid helium at 1.5K on samples of NaClO/sub 3/ and KClO/sub 3/, each of which exhibit a /sup 35/Cl NQR transition at about 30 MHz. In the third experiment, precessing nuclear quadrupole moments were observed to induce oscillating electric dipole moments in neighboring atoms. The /sup 35/Cl nuclei of a single crystal of NaClO/sub 3/ placed between the plates of a capacitor were excited into precession by a rf pulse.

  11. Initial Experience with the Resonance Metallic Stent for Antegrade Ureteric Stenting

    SciTech Connect

    Wah, Tze M. Irving, Henry C.; Cartledge, Jon

    2007-07-15

    Background and purpose. We describe our initial experience with a new metallic ureteric stent which has been designed to provide long-term urinary drainage in patients with malignant ureteric strictures. The aim is to achieve longer primary patency rates than conventional polyurethane ureteric stents, where encrustation and compression by malignant masses limit primary patency. The Resonance metallic double-pigtail ureteric stent (Cook, Ireland) is constructed from coiled wire spirals of a corrosion-resistant alloy designed to minimize tissue in-growth and resist encrustation, and the manufacturer recommends interval stent change at 12 months. Methods. Seventeen Resonance stents were inserted via an antegrade approach into 15 patients between December 2004 and March 2006. The causes of ureteric obstruction were malignancies of the bladder (n = 4), colon (n = 3), gynecologic (n = 5), and others (n = 3). Results. One patient had the stent changed after 12 months, and 3 patients had their stents changed at 6 months. These stents were draining adequately with minimal encrustation. Four patients are still alive with functioning stents in situ for 2-10 months. Seven patients died with functioning stents in place (follow-up periods of 1 week to 8 months). Three stents failed from the outset due to bulky pelvic malignancy resulting in high intravesical pressure, as occurs with conventional plastic stents. Conclusion. Our initial experience with the Resonance metallic ureteric stent indicates that it may provide adequate long-term urinary drainage (up to 12 months) in patients with malignant ureteric obstruction but without significantly bulky pelvic disease. This obviates the need for regular stent changes and would offer significant benefit for these patients with limited life expectancy.

  12. Resonant Frequency Spin Flipper for the nHe3 Experiment

    NASA Astrophysics Data System (ADS)

    Hayes, Christopher

    2014-03-01

    The n3He experiment, currently being installed on beamline-13 at ORNL's Spallation Neutron Source (SNS), is designed to measure the proton asymmetry associated with the interaction of neutrons with a gas of 3He via n +23He =13H +11H + 765 KeV . The experiment uses a Resonant Frequency Spin Flipper (RFSF) to flip the neutron spins. The spin flipper is similar to the one described by P.N. Seo et al. (PR ST Accel. Beams 11, 084701 2008) with significant improvements. Most important is the inclusion of a ``double cosine-theta'' winding pattern that provides a highly uniform interior field with no fringing. A critical feature of the coil is complex flux returns whose construction was made possible through the utilization of 3D print technology.

  13. Optimization of surface plasmon resonance experiments: Case of high mobility group box 1 (HMGB1) interactions.

    PubMed

    Anggayasti, Wresti L; Mancera, Ricardo L; Bottomley, Steven; Helmerhorst, Erik

    2016-04-15

    Surface plasmon resonance (SPR) is a powerful technique for evaluating protein-protein interactions in real time. However, inappropriately optimized experiments can often lead to problems in the interpretation of data, leading to unreliable kinetic constants and binding models. Optimization of SPR experiments involving "sticky" proteins, or proteins that tend to aggregate, represents a typical scenario where it is important to minimize errors in the data and the kinetic analysis of those data. This is the case of High Mobility Group Box 1 and the receptor of advanced glycation end products. A number of improvements in protein purification, buffer composition, immobilization conditions, and the choice of flow rate are shown to result in substantial improvements in the accurate characterization of the interactions of these proteins and the derivation of the corresponding kinetic constants. PMID:26869083

  14. 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.

  15. Sparsely-sampled High-resolution 4-D Experiments for Efficient Backbone Resonance Assignment of Disordered Proteins

    PubMed Central

    Wen, Jie; Wu, Jihui; Zhou, Pei

    2011-01-01

    Intrinsically disordered proteins (IDPs) play important roles in many critical cellular processes. Due to their limited chemical shift dispersion, IDPs often require four pairs of resonance connectivities (Hα, Cα, Cβ and CO) for establishing sequential backbone assignment. Because most conventional 4-D triple-resonance experiments share an overlapping Cα evolution period, combining existing 4-D experiments does not offer an optimal solution for non-redundant collection of a complete set of backbone resonances. Using alternative chemical shift evolution schemes, we propose a new pair of 4-D triple resonance experiments—HA(CA)CO(CA)NH/HA(CA)CONH—that complement the 4-D HNCACB/HN(CO)CACB experiments to provide complete backbone resonance information. Collection of high-resolution 4-D spectra with sparse sampling and FFT-CLEAN processing enables efficient acquisition and assignment of complete backbone resonances of IDPs. Importantly, because the CLEAN procedure iteratively identifies resonance signals and removes their associating aliasing artifacts, it greatly reduces the dependence of the reconstruction quality on sampling schemes and produces high-quality spectra even with less-than-optimal sampling schemes. PMID:21277815

  16. A study of the bis(4-chlorophenyl) sulphide by 35Cl nuclear quadrupole resonance and ab initio calculations

    NASA Astrophysics Data System (ADS)

    Osán, T. M.; Schürrer, C.; Schneider, J.; Briñon, M. C.; Fierro, N.; Brunetti, A.

    1999-11-01

    As an extension of previous works in sulphur-substituted biphenyls, a complete pulsed 35Cl nuclear quadrupole resonance (NQR) study of the bis(4-chlorophenyl) sulphide compound is presented. In order to characterize the structural thermal behaviour of the solid phase, the NQR spectra and spin-lattice relaxation times were recorded from 80 K to 330 K. In addition, ab initio calculations at HF/3-21G* and 6-31G* levels were performed in order to obtain information about the equilibrium geometry and the torsional potential of the free bis(4-chlorophenyl) sulphide molecule. The NQR study results show that the title compound presents a unique stable crystalline phase in the scanned temperature range. This phase diagram contrasts notably with those observed at the same temperatures in bis(4-chlorophenyl) sulphone and bis(4-chlorophenyl) sulphoxide, which show an incommensurate phase transition and two-phase coexistence, respectively. The narrow NQR line observed suggests that the 35Cl atoms in the unit cell are in crystallographic equivalent positions. Ab initio calculations for the free molecule show that the symmetry point group is C2 and the dihedral angle is 60°. The results are discussed and compared with the known information about the sulphone and sulphoxide derivatives. The effect of the interphenyl linking group is also discussed, in order to understand the evolution of the phase diagram in this group of compounds.

  17. Identification of Copper(II) Complexes in Aqueous Solution by Electron Spin Resonance: An Undergraduate Coordination Chemistry Experiment.

    ERIC Educational Resources Information Center

    Micera, G.; And Others

    1984-01-01

    Background, procedures, and results are provided for an experiment which examines, through electron spin resonance spectroscopy, complex species formed by cupric and 2,6-dihydroxybenzoate ions in aqueous solutions. The experiment is illustrative of several aspects of inorganic and coordination chemistry, including the identification of species…

  18. Ferromagnetic resonance experiments in an obliquely deposited FeCo-Al2O3 film system

    NASA Astrophysics Data System (ADS)

    Lesnik, N. A.; Oates, C. J.; Smith, G. M.; Riedi, P. C.; Kakazei, G. N.; Kravets, A. F.; Wigen, P. E.

    2003-11-01

    Granular cermet films (Fe50Co50)x-(Al2O3)1-x fabricated using the electron-beam coevaporation technique at oblique incidence of FeCo and alumina atom fluxes have been found to exhibit both oblique and in-plane uniaxial magnetic anisotropy. This anisotropy first appears just below the percolation threshold due to a magnetic coupling of particles taking place at a certain stage of their growth and coalescence. The FeCo content x varied from 0.07 to 0.49. A simple model of the film microstructure is presented based on the results of magnetization measurements and ferromagnetic resonance at intermediate (9.4 GHz) and high (94 GHz) frequencies. At 94 GHz the concentration dependence of the effective anisotropy field follows the solid solution law, since then the magnetic field is sufficient to magnetize the films close to saturation. The 9.4 GHz data points deviate from the solid solution line below the percolation threshold due to both modification of the resonance fields by intergranular interactions in nonsaturated films and the reduction of the average magnetization of granules, comparing to the saturation magnetization, at room temperature. Different mechanisms of line broadening observed at frequencies used in experiments are also discussed.

  19. [Development of RF coil of permanent magnet mini-magnetic resonance imager and mouse imaging experiments].

    PubMed

    Hou, Shulian; Xie, Huantong; Chen, Wei; Wang, Guangxin; Zhao, Qiang; Li, Shiyu

    2014-10-01

    In the development of radio frequency (RF) coils for better quality of the mini-type permanent magnetic resonance imager for using in the small animal imaging, the solenoid RF coil has a special advantage for permanent magnetic system based on analyses of various types.of RF coils. However, it is not satisfied for imaging if the RF coils are directly used. By theoretical analyses of the magnetic field properties produced from the solenoid coil, the research direction was determined by careful studies to raise further the uniformity of the magnetic field coil, receiving coil sensitivity for signals and signal-to-noise ratio (SNR). The method had certain advantages and avoided some shortcomings of the other different coil types, such as, birdcage coil, saddle shaped coil and phased array coil by using the alloy materials (from our own patent). The RF coils were designed, developed and made for keeled applicable to permanent magnet-type magnetic resonance imager, multi-coil combination-type, single-channel overall RF receiving coil, and applied for a patent. Mounted on three instruments (25 mm aperture, with main magnetic field strength of 0.5 T or 1.5 T, and 50 mm aperture, with main magnetic field strength of 0.48 T), we performed experiments with mice, rats, and nude mice bearing tumors. The experimental results indicated that the RF receiving coil was fully applicable to the permanent magnet-type imaging system. PMID:25764715

  20. On the Phase Dependence of Double-Resonance Experiments in Rotational Spectroscopy

    NASA Astrophysics Data System (ADS)

    Schmitz, David; Shubert, V. Alvin; Krin, Anna; Patterson, David; Schnell, Melanie

    2015-06-01

    We report double-resonance experiments using broadband chirped-pulse Fourier transform microwave spectroscopy that facilitate spectral assignment and yield information about weak transitions with high resolution and sensitivity. Using the diastereomers menthone and isomenthone as examples, we investigate both the amplitude and the phase dependence of the free-induction decay of the microwave signal transition from pumping a radio frequency transition sharing a common level. We observe a strong phase change when scanning the radio frequency through molecular resonance. The direction of the phase change depends on the energy level arrangement, i.e., if it is progressive or regressive. The experimental results can be simulated using the density-matrix formalism using the three-level Bloch equations and are best described with the AC Stark effect within the dressed-state picture, resulting in an Autler-Townes splitting. The characteristic phase inversion allows for a) the precise frequency determination of the typically weak radio frequency transitions exploiting the high sensitivity of the connected strong microwave signal transition and b) definitive information about the connectivity of the energy levels involved, i.e., progressive vs. regressive arrangements.

  1. Magnetic resonance imaging (MRI): method and early clinical experiences in diseases of the central nervous system.

    PubMed

    Huk, W J; Gademann, G

    1984-01-01

    Magnetic resonance imaging (MRI) has undergone a rapid development which is still continuing. In this article a survey is given of the present status of this new diagnostic tool in the evaluation of diseases of the central nervous system. When atoms with uneven numbers of protons or neutrons in a homogeneous magnetic field are tilted against the main vector of this field by a radiofrequency pulse, nuclear magnetic resonance can be observed. During the relaxation of the little dipoles back to the direction of the underlying magnetic field, a resonance signal is generated. The superposition of variable field gradients enables the scanning of sectional images in the axial, frontal and sagittal plane. The variables of H+-magnetic resonance which can be utilized for imaging are: the proton density, the relaxation times T1 (spin-lattice) and T2 (spin-spin) and flow effects. While the proton density in organic tissue fluctuates only by some 10%, the relaxation times may vary by several hundred per cent. Tissue contrast, therefore, is mainly based on relaxation times differences. The image character can also be influenced by variations of imaging parameters (i.e. repetition rate, interpulse delay, read out or echo delay) in different imaging sequences, such as the spin-echo and the inversion recovery technique. Depending on these imaging parameters T1 and T2 will contribute to the signal to a varying degree. This fact is most important for the diagnostic information of MRI. In initial clinical experiences in the diagnosis of diseases of the central nervous system, MRI has demonstrated high sensitivity in the detection of lesions (such as oedema, neoplasms, demyelinating disease), but less significance in lesion discrimination. In spinal disease the direct sagittal imaging of MRI enables MRI-myelography without contrast medium, superior to conventional myelography in many cases. For detailed evaluation of disc disease, however, the spatial resolution still has to be improved. Promising results have been obtained from flow effects. Depending on the flow velocity of blood, vessels appear white with intensive signals (slow flow) or black due to low signal intensities (rapid flow). MRI-angiography including measurement of blood flow seems possible. MRI-contrast media are not yet available for routine clinical use. Promising results have been reported on the basis of rare-earth elements, such as gadolinium Gd3+. These substances decrease T1 and T2 with subsequent increase in signal intensity. Concerning harmful side-effects of MRI, three possible sources have to be considered: the static magnetic field, the changing magnetic field, and radiofrequency heating.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:6397697

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

    NASA Astrophysics Data System (ADS)

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

    2006-06-01

    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 upon hydration of salts containing sodium and potassium ions are explained as a consequence of H-bonds formation and accompanied effects of charge redistribution. Our studies can be useful in searching for the derivatives of dichloroisocyanuric acid revealing higher antimicrobial activity.

  3. Optimization of capacitive acoustic resonant sensor using numerical simulation and design of experiment.

    PubMed

    Haque, Rubaiyet Iftekharul; Loussert, Christophe; Sergent, Michelle; Benaben, Patrick; Boddaert, Xavier

    2015-01-01

    Optimization of the acoustic resonant sensor requires a clear understanding of how the output responses of the sensor are affected by the variation of different factors. During this work, output responses of a capacitive acoustic transducer, such as membrane displacement, quality factor, and capacitance variation, are considered to evaluate the sensor design. The six device parameters taken into consideration are membrane radius, backplate radius, cavity height, air gap, membrane tension, and membrane thickness. The effects of factors on the output responses of the transducer are investigated using an integrated methodology that combines numerical simulation and design of experiments (DOE). A series of numerical experiments are conducted to obtain output responses for different combinations of device parameters using finite element methods (FEM). Response surface method is used to identify the significant factors and to develop the empirical models for the output responses. Finally, these results are utilized to calculate the optimum device parameters using multi-criteria optimization with desirability function. Thereafter, the validating experiments are designed and deployed using the numerical simulation to crosscheck the responses. PMID:25894937

  4. Anvil cell gasket design for high pressure nuclear magnetic resonance experiments beyond 30 GPa

    SciTech Connect

    Meier, Thomas; Haase, Jürgen

    2015-12-15

    Nuclear magnetic resonance (NMR) experiments are reported at up to 30.5 GPa of pressure using radiofrequency (RF) micro-coils with anvil cell designs. These are the highest pressures ever reported with NMR, and are made possible through an improved gasket design based on nano-crystalline powders embedded in epoxy resin. Cubic boron-nitride (c-BN), corundum (α-Al{sub 2}O{sub 3}), or diamond based composites have been tested, also in NMR experiments. These composite gaskets lose about 1/2 of their initial height up to 30.5 GPa, allowing for larger sample quantities and preventing damages to the RF micro-coils compared to precipitation hardened CuBe gaskets. It is shown that NMR shift and resolution are less affected by the composite gaskets as compared to the more magnetic CuBe. The sensitivity can be as high as at normal pressure. The new, inexpensive, and simple to engineer gaskets are thus superior for NMR experiments at high pressures.

  5. Anvil cell gasket design for high pressure nuclear magnetic resonance experiments beyond 30 GPa

    NASA Astrophysics Data System (ADS)

    Meier, Thomas; Haase, Jürgen

    2015-12-01

    Nuclear magnetic resonance (NMR) experiments are reported at up to 30.5 GPa of pressure using radiofrequency (RF) micro-coils with anvil cell designs. These are the highest pressures ever reported with NMR, and are made possible through an improved gasket design based on nano-crystalline powders embedded in epoxy resin. Cubic boron-nitride (c-BN), corundum (α-Al2O3), or diamond based composites have been tested, also in NMR experiments. These composite gaskets lose about 1/2 of their initial height up to 30.5 GPa, allowing for larger sample quantities and preventing damages to the RF micro-coils compared to precipitation hardened CuBe gaskets. It is shown that NMR shift and resolution are less affected by the composite gaskets as compared to the more magnetic CuBe. The sensitivity can be as high as at normal pressure. The new, inexpensive, and simple to engineer gaskets are thus superior for NMR experiments at high pressures.

  6. Anvil cell gasket design for high pressure nuclear magnetic resonance experiments beyond 30 GPa.

    PubMed

    Meier, Thomas; Haase, Jürgen

    2015-12-01

    Nuclear magnetic resonance (NMR) experiments are reported at up to 30.5 GPa of pressure using radiofrequency (RF) micro-coils with anvil cell designs. These are the highest pressures ever reported with NMR, and are made possible through an improved gasket design based on nano-crystalline powders embedded in epoxy resin. Cubic boron-nitride (c-BN), corundum (α-Al2O3), or diamond based composites have been tested, also in NMR experiments. These composite gaskets lose about 1/2 of their initial height up to 30.5 GPa, allowing for larger sample quantities and preventing damages to the RF micro-coils compared to precipitation hardened CuBe gaskets. It is shown that NMR shift and resolution are less affected by the composite gaskets as compared to the more magnetic CuBe. The sensitivity can be as high as at normal pressure. The new, inexpensive, and simple to engineer gaskets are thus superior for NMR experiments at high pressures. PMID:26724046

  7. Detailed design of a resonantly enhanced axion-photon regeneration experiment

    SciTech Connect

    Mueller, Guido; Sikivie, Pierre; Tanner, D. B.; Bibber, Karl van

    2009-10-01

    A resonantly enhanced photon-regeneration experiment to search for the axion or axionlike particles is described. This experiment is a shining light through walls study, where photons traveling through a strong magnetic field are (in part) converted to axions; the axions can pass through an opaque wall and convert (in part) back to photons in a second region of strong magnetic field. The photon regeneration is enhanced by employing matched Fabry-Perot optical cavities, with one cavity within the axion generation magnet and the second within the photon-regeneration magnet. Compared to simple single-pass photon regeneration, this technique would result in a gain of (F/{pi}){sup 2}, where F is the finesse of each cavity. This gain could feasibly be as high as 10{sup 10}, corresponding to an improvement in the sensitivity to the axion-photon coupling, g{sub a{gamma}}{sub {gamma}}, of order (F/{pi}){sup 1/2}{approx}300. This improvement would enable, for the first time, a purely laboratory experiment to probe axion-photon couplings at a level competitive with, or superior to, limits from stellar evolution or solar axion searches. This report gives a detailed discussion of the scheme for actively controlling the two Fabry-Perot cavities and the laser frequencies, and describes the heterodyne signal detection system, with limits ultimately imposed by shot noise.

  8. Optimization of Capacitive Acoustic Resonant Sensor Using Numerical Simulation and Design of Experiment

    PubMed Central

    Haque, Rubaiyet Iftekharul; Loussert, Christophe; Sergent, Michelle; Benaben, Patrick; Boddaert, Xavier

    2015-01-01

    Optimization of the acoustic resonant sensor requires a clear understanding of how the output responses of the sensor are affected by the variation of different factors. During this work, output responses of a capacitive acoustic transducer, such as membrane displacement, quality factor, and capacitance variation, are considered to evaluate the sensor design. The six device parameters taken into consideration are membrane radius, backplate radius, cavity height, air gap, membrane tension, and membrane thickness. The effects of factors on the output responses of the transducer are investigated using an integrated methodology that combines numerical simulation and design of experiments (DOE). A series of numerical experiments are conducted to obtain output responses for different combinations of device parameters using finite element methods (FEM). Response surface method is used to identify the significant factors and to develop the empirical models for the output responses. Finally, these results are utilized to calculate the optimum device parameters using multi-criteria optimization with desirability function. Thereafter, the validating experiments are designed and deployed using the numerical simulation to crosscheck the responses. PMID:25894937

  9. Measurement of the 14N nuclear quadrupole resonance frequencies by the solid effect

    NASA Astrophysics Data System (ADS)

    Seliger, J.; Žagar, V.

    2008-07-01

    1H- 14N nuclear quadrupole double resonance using magnetic field cycling between high and low magnetic field and solid effect in the low magnetic field is analyzed in details. The transition probabilities per unit time for the solid-effect transitions are calculated. The double resonance spectra are calculated in the limiting cases of fast and slow nitrogen spin-lattice relaxation. The double resonance spectra are measured in histamine and quinolinic acid. The experimental spectra are analyzed and the 14N NQR frequencies are determined.

  10. Robust optimal design of diffusion-weighted magnetic resonance experiments for skin microcirculation.

    PubMed

    Choi, J; Raguin, L G

    2010-10-01

    Skin microcirculation plays an important role in several diseases including chronic venous insufficiency and diabetes. Magnetic resonance (MR) has the potential to provide quantitative information and a better penetration depth compared with other non-invasive methods such as laser Doppler flowmetry or optical coherence tomography. The continuous progress in hardware resulting in higher sensitivity must be coupled with advances in data acquisition schemes. In this article, we first introduce a physical model for quantifying skin microcirculation using diffusion-weighted MR (DWMR) based on an effective dispersion model for skin leading to a q-space model of the DWMR complex signal, and then design the corresponding robust optimal experiments. The resulting robust optimal DWMR protocols improve the worst-case quality of parameter estimates using nonlinear least squares optimization by exploiting available a priori knowledge of model parameters. Hence, our approach optimizes the gradient strengths and directions used in DWMR experiments to robustly minimize the size of the parameter estimation error with respect to model parameter uncertainty. Numerical evaluations are presented to demonstrate the effectiveness of our approach as compared to conventional DWMR protocols. PMID:20727799

  11. Robust optimal design of diffusion-weighted magnetic resonance experiments for skin microcirculation

    NASA Astrophysics Data System (ADS)

    Choi, J.; Raguin, L. G.

    2010-10-01

    Skin microcirculation plays an important role in several diseases including chronic venous insufficiency and diabetes. Magnetic resonance (MR) has the potential to provide quantitative information and a better penetration depth compared with other non-invasive methods such as laser Doppler flowmetry or optical coherence tomography. The continuous progress in hardware resulting in higher sensitivity must be coupled with advances in data acquisition schemes. In this article, we first introduce a physical model for quantifying skin microcirculation using diffusion-weighted MR (DWMR) based on an effective dispersion model for skin leading to a q-space model of the DWMR complex signal, and then design the corresponding robust optimal experiments. The resulting robust optimal DWMR protocols improve the worst-case quality of parameter estimates using nonlinear least squares optimization by exploiting available a priori knowledge of model parameters. Hence, our approach optimizes the gradient strengths and directions used in DWMR experiments to robustly minimize the size of the parameter estimation error with respect to model parameter uncertainty. Numerical evaluations are presented to demonstrate the effectiveness of our approach as compared to conventional DWMR protocols.

  12. Anesthesia during high-field intraoperative magnetic resonance imaging experience with 80 consecutive cases.

    PubMed

    Schmitz, Bernd; Nimsky, Christopher; Wendel, Georg; Wienerl, Juergen; Ganslandt, Oliver; Jacobi, Klaus; Fahlbusch, Rudolf; Schüttler, Juergen

    2003-07-01

    Intraoperative magnetic resonance imaging (MRI) has been used for years to update neuronavigation and for intraoperative resection control. For this purpose, low-field (0.1-0.2 T) MR scanners have been installed in the operating room, which, in contrast to machines using higher magnetic field strength, allowed the use of standard anesthetic and surgical equipment. However, these low-field MR systems provided only minor image quality and a limited battery of MR sequences, excluding functional MRI, diffusion-weighted MRI, or MR angiography and spectroscopy. Based on these advantages, a concept using high-field MRI (1.5 T) with intraoperative functional neuronavigational guidance has been developed that required adaptation of the anesthetic regimen to working in the close vicinity to the strong magnetic field. In this paper the authors present their experience with the first 80 consecutive patients who received anesthesia in a specially designed radio frequency-shielded operating room equipped with a high-field (1.5 T) MR scanner. We describe the MR-compatible anesthesia equipment used including ventilator, monitoring, and syringe pumps, which allow standard neuroanesthesia in this new and challenging environment. This equipment provides the use of total intravenous anesthesia with propofol and remifentanil allowing rapid extubation and neurologic examination following surgery. In addition, extended intraoperative monitoring including EEG monitoring required for intracranial surgery is possible. Moreover, problems and dangers related to the effects of the strong magnetic field are discussed. PMID:12826974

  13. Electron Spin Resonance Experiments on a Single Electron in Silicon Implanted with Phosphorous

    NASA Astrophysics Data System (ADS)

    Luhman, Dwight R.; Nguyen, K.; Tracy, L. A.; Carr, S.; Borchardt, J.; Bishop, N.; Ten Eyck, G.; Pluym, T.; Wendt, J.; Lilly, M. P.; Carroll, M. S.

    2015-03-01

    In this talk we will discuss the results of our ongoing experiments involving electron spin resonance (ESR) on a single electron in a natural silicon sample. The sample consists of an SET, defined by lithographic polysilicon gates, coupled to nearby phosphorous donors. The SET is used to detect charge transitions and readout the spin of the electron being investigated with ESR. The measurements were done with the sample at dilution refrigerator temperatures in the presence of a 1.3 T magnetic field. We will present data demonstrating Rabi oscillations of a single electron in this system as well as measurements of the coherence time, T2. We will also discuss our results using these and various other pulsing schemes in the context of a donor-SET system. This work was performed, in part, at the Center for Integrated Nanotechnologies, a U.S. DOE Office of Basic Energy Sciences user facility. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a Lockheed-Martin Company, for the U. S. Department of Energy under Contract No. DE-AC04-94AL85000.

  14. Rapid estimation of nuclear magnetic resonance experiment time in low-concentration environmental samples.

    PubMed

    Masoom, Hussain; Courtier-Murias, Denis; Farooq, Hashim; Soong, Ronald; Simpson, Myrna J; Maas, Werner; Kumar, Rajeev; Monette, Martine; Stronks, Henry; Simpson, André J

    2013-01-01

    Nuclear magnetic resonance (NMR) spectroscopy is an essential tool for studying environmental samples but is often hindered by low sensitivity, especially for the direct detection of nuclei such as(13) C. In very heterogeneous samples with NMR nuclei at low abundance, such as soils, sediments, and air particulates, it can take days to acquire a conventional(13) C spectrum. The present study describes a prescreening method that permits the rapid prediction of experimental run time in natural samples. The approach focuses the NMR chemical shift dispersion into a single spike, and, even in samples with extremely low carbon content, the spike can be observed in two to three minutes, or less. The intensity of the spike is directly proportional to the total concentration of nuclei of interest in the sample. Consequently, the spike intensity can be used as a powerful prescreening method that answers two key questions: (1) Will this sample produce a conventional NMR spectrum? (2) How much instrument time is required to record a spectrum with a specific signal-to-noise (S/N) ratio? The approach identifies samples to avoid (or pretreat) and permits additional NMR experiments to be performed on samples producing high-quality NMR data. Applications in solid- and liquid-state(13) C NMR are demonstrated, and it is shown that the technique is applicable to a range of nuclei. PMID:23065696

  15. Experiments with biased side electrodes in electron cyclotron resonance ion sources.

    PubMed

    Drentje, A G; Kitagawa, A; Uchida, T; Rácz, R; Biri, S

    2014-02-01

    The output of highly charged ions from an electron cyclotron resonance ion source (ECRIS) consists of ionic losses from a highly confined plasma. Therefore, an increase of the output of the ions of interest always is a compromise between an increase in the confinement and an increase of the losses. One route towards a solution consists of attacking the losses in directions - i.e., radial directions - that do not contribute to the required output. This was demonstrated in an experiment (using the Kei ECRIS at NIRS, Japan) where radial losses were electrostatically reduced by positively biasing one set of six "side" electrodes surrounding the plasma in side-ward directions attached (insulated) to the cylindrical wall of the plasma chamber. Recently new studies were performed in two laboratories using two essentially different ion sources. At the BioNano ECRIS (Toyo University, Japan) various sets of electrodes were used; each of the electrodes could be biased individually. At the Atomki ECRIS (Hungary), one movable, off-axis side electrode was applied in technically two versions. The measurements show indeed a decrease of ionic losses but different effectivities as compared to the biased disk. PMID:24593500

  16. Tracking Simulation of Third-Integer Resonant Extraction for Fermilab's Mu2e Experiment

    SciTech Connect

    Park, Chong Shik; Amundson, James; Michelotti, Leo

    2015-02-13

    The Mu2e experiment at Fermilab requires acceleration and transport of intense proton beams in order to deliver stable, uniform particle spills to the production target. To meet the experimental requirement, particles will be extracted slowly from the Delivery Ring to the external beamline. Using Synergia2, we have performed multi-particle tracking simulations of third-integer resonant extraction in the Delivery Ring, including space charge effects, physical beamline elements, and apertures. A piecewise linear ramp profile of tune quadrupoles was used to maintain a constant averaged spill rate throughout extraction. To study and minimize beam losses, we implemented and introduced a number of features, beamline element apertures, and septum plane alignments. Additionally, the RF Knockout (RFKO) technique, which excites particles transversely, is employed for spill regulation. Combined with a feedback system, it assists in fine-tuning spill uniformity. Simulation studies were carried out to optimize the RFKO feedback scheme, which will be helpful in designing the final spill regulation system.

  17. Experiments with biased side electrodes in electron cyclotron resonance ion sources

    SciTech Connect

    Drentje, A. G. Kitagawa, A.; Uchida, T.; Rácz, R.; Biri, S.

    2014-02-15

    The output of highly charged ions from an electron cyclotron resonance ion source (ECRIS) consists of ionic losses from a highly confined plasma. Therefore, an increase of the output of the ions of interest always is a compromise between an increase in the confinement and an increase of the losses. One route towards a solution consists of attacking the losses in directions – i.e., radial directions – that do not contribute to the required output. This was demonstrated in an experiment (using the Kei ECRIS at NIRS, Japan) where radial losses were electrostatically reduced by positively biasing one set of six “side” electrodes surrounding the plasma in side-ward directions attached (insulated) to the cylindrical wall of the plasma chamber. Recently new studies were performed in two laboratories using two essentially different ion sources. At the BioNano ECRIS (Toyo University, Japan) various sets of electrodes were used; each of the electrodes could be biased individually. At the Atomki ECRIS (Hungary), one movable, off-axis side electrode was applied in technically two versions. The measurements show indeed a decrease of ionic losses but different effectivities as compared to the biased disk.

  18. Measurements of radial profiles of ion cyclotron resonance heating on the Tandem Mirror Experiment-Upgrade

    SciTech Connect

    Falabella, S.

    1988-05-11

    A small Radial Energy Analyzer (REA) was used on the Tandem Mirror Experiment-Upgrade (TMX-U), at Lawerence Livermore National Laboratory, to investigate the radial profiles of ion temperature, density, and plasma potential during Ion Cyclotron Resonance Heating (ICRH). The probe has been inserted into the central-cell plasma at temperatures of 200 eV and densities of 3 x 10/sup 12/cm/sup /minus 3// without damage to the probe, or major degradation of the plasma. This analyzer has indicated an increase in ion temperature from near 20 eV before ICRH to near 150 eV during ICRH, with about 60 kW of broadcast power. The REA measurements were cross-checked against other diagnostics on TMX-U and found to be consistent. The ion density measurement was compared to the line-density measured by microwave interferometry and found to agree within 10 to 20%. A radial intergral of n/sub i/T/sub i/ as measured by the REA shows good agreement with the diamagnetic loop measurement of plasma energy. The radial density profile is observed to broaden during the RF heating pulses, without inducing additional radial losses in the core plasma. The radial profile of plasma is seen to vary from axially peaked, to nearly flat as the plasma conditions carried over the series of experiments. To relate the increase in ion temperature to power absorbed by the plasma, a power balance as a function of radius was performed. The RF power absorbed is set equal to the sum of the losses during ICRH, minus those without ICRH. This method accounts for more than 70% of the broadcast power using a simple power balance model. The measured radial profile of the RF heating was compared to the calculations of two codes, ANTENA and GARFIELD, to test their effectiveness as predictors of power absorption profiles for TMX-U. 62 refs., 63 figs., 7 tabs.

  19. Injection Seeding of Ti:Al2O3 in an unstable resonator theory and experiment

    NASA Technical Reports Server (NTRS)

    Barnes, J. C.; Wang, L. G.; Barnes, N. P.; Edwards, W. C.; Cheng, W. A.; Hess, R. V.; Lockard, G. E.; Ponsardin, P. L.

    1991-01-01

    Injection Seeding of a Ti:Al2O3 unstable resonator using both a pulsed single-mode Ti:Al2O3 laser and a continuous wave laser diode has been characterized. Results are compared with a theory which calculates injection seeding as function of seed and resonator alignment, beam profiles, and power.

  20. HNCCH-TOCSY, a triple resonance experiment for the correlation of backbone 13C alpha and 15N resonances with aliphatic side-chain proton resonances and for measuring vicinal 13CO,1H beta coupling constants in proteins.

    PubMed

    Weisemann, R; Löhr, F; Rüterjans, H

    1994-07-01

    A 3D triple resonance experiment has been designed to provide intraresidual and sequential correlations between amide nitrogens and alpha-carbons in uniformly 13C/15N-labeled proteins. In-phase 13C alpha magnetization is transferred to the aliphatic side-chain protons via the side-chain carbons using a CC-TOCSY mixing sequence. Thus, the experiment alleviates the resonance assignment process by providing information about the amino acid type as well as establishing sequential connectivities. Leaving the carbonyl spins untouched throughout the transfer from 13C alpha to 1H beta leads to E.COSY-type cross peaks, from which the 3JH beta CO coupling constants can be evaluated. The pulse sequence is applied to oxidized Desulfovibrio vulgaris flavodoxin. PMID:8075544

  1. 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.

  2. Search for high mass dilepton resonances in pp collisions at √{ s} = 7 TeV with the ATLAS experiment

    NASA Astrophysics Data System (ADS)

    Aad, G.; Abbott, B.; Abdallah, J.; Abdelalim, A. A.; Abdesselam, A.; Abdinov, O.; Abi, B.; Abolins, M.; Abramowicz, H.; Abreu, H.; Acerbi, E.; Acharya, B. S.; Adams, D. L.; Addy, T. N.; Adelman, J.; Aderholz, M.; Adomeit, S.; Adragna, P.; Adye, T.; Aefsky, S.; Aguilar-Saavedra, J. A.; Aharrouche, M.; Ahlen, S. P.; Ahles, F.; Ahmad, A.; Ahsan, M.; Aielli, G.; Akdogan, T.; Åkesson, T. P. A.; Akimoto, G.; Akimov, A. V.; Akiyama, A.; Alam, M. S.; Alam, M. A.; Albrand, S.; Aleksa, M.; Aleksandrov, I. N.; Alessandria, F.; Alexa, C.; Alexander, G.; Alexandre, G.; Alexopoulos, T.; Alhroob, M.; Aliev, M.; Alimonti, G.; Alison, J.; Aliyev, M.; Allport, P. P.; Allwood-Spiers, S. E.; Almond, J.; Aloisio, A.; Alon, R.; Alonso, A.; Alviggi, M. G.; Amako, K.; Amaral, P.; Amelung, C.; Ammosov, V. V.; Amorim, A.; Amorós, G.; Amram, N.; Anastopoulos, C.; Andeen, T.; Anders, C. F.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Andrieux, M.-L.; Anduaga, X. S.; Angerami, A.; Anghinolfi, F.; Anjos, N.; Annovi, A.; Antonaki, A.; Antonelli, M.; Antonelli, S.; Antonov, A.; Antos, J.; Anulli, F.; Aoun, S.; Aperio Bella, L.; Apolle, R.; Arabidze, G.; Aracena, I.; Arai, Y.; Arce, A. T. H.; Archambault, J. P.; Arfaoui, S.; Arguin, J.-F.; Arik, E.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnault, C.; Artamonov, A.; Artoni, G.; Arutinov, D.; Asai, S.; Asfandiyarov, R.; Ask, S.; Åsman, B.; Asquith, L.; Assamagan, K.; Astbury, A.; Astvatsatourov, A.; Atoian, G.; Aubert, B.; Auerbach, B.; Auge, E.; Augsten, K.; Aurousseau, M.; Austin, N.; Avramidou, R.; Axen, D.; Ay, C.; Azuelos, G.; Azuma, Y.; Baak, M. A.; Baccaglioni, G.; Bacci, C.; Bach, A. M.; Bachacou, H.; Bachas, K.; Bachy, G.; Backes, M.; Backhaus, M.; Badescu, E.; Bagnaia, P.; Bahinipati, S.; Bai, Y.; Bailey, D. C.; Bain, T.; Baines, J. T.; Baker, O. K.; Baker, M. D.; Baker, S.; Baltasar Dos Santos Pedrosa, F.; Banas, E.; Banerjee, P.; Banerjee, Sw.; Banfi, D.; Bangert, A.; Bansal, V.; Bansil, H. S.; Barak, L.; Baranov, S. P.; Barashkou, A.; Barbaro Galtieri, A.; Barber, T.; Barberio, E. L.; Barberis, D.; Barbero, M.; Bardin, D. Y.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnett, B. M.; Barnett, R. M.; Baroncelli, A.; Barr, A. J.; Barreiro, F.; Barreiro Guimarães da Costa, J.; Barrillon, P.; Bartoldus, R.; Barton, A. E.; Bartsch, D.; Bartsch, V.; Bates, R. L.; Batkova, L.; Batley, J. R.; Battaglia, A.; Battistin, M.; Battistoni, G.; Bauer, F.; Bawa, H. S.; Beare, B.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, H. P.; Beckingham, M.; Becks, K. H.; Beddall, A. J.; Beddall, A.; Bedikian, S.; Bednyakov, V. A.; Bee, C. P.; Begel, M.; Behar Harpaz, S.; Behera, P. K.; Beimforde, M.; Belanger-Champagne, C.; Bell, P. J.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellina, F.; Bellomo, M.; Belloni, A.; Beloborodova, O.; Belotskiy, K.; Beltramello, O.; Ben Ami, S.; Benary, O.; Benchekroun, D.; Benchouk, C.; Bendel, M.; Benedict, B. H.; Benekos, N.; Benhammou, Y.; Benjamin, D. P.; Benoit, M.; Bensinger, J. R.; Benslama, K.; Bentvelsen, S.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Berglund, E.; Beringer, J.; Bernardet, K.; Bernat, P.; Bernhard, R.; Bernius, C.; Berry, T.; Bertin, A.; Bertinelli, F.; Bertolucci, F.; Besana, M. I.; Besson, N.; Bethke, S.; Bhimji, W.; Bianchi, R. M.; Bianco, M.; Biebel, O.; Bieniek, S. P.; Biesiada, J.; Biglietti, M.; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Biscarat, C.; Bitenc, U.; Black, K. M.; Blair, R. E.; Blanchard, J.-B.; Blanchot, G.; Blocker, C.; Blocki, J.; Blondel, A.; Blum, W.; Blumenschein, U.; Bobbink, G. J.; Bobrovnikov, V. B.; Bocchetta, S. S.; Bocci, A.; Boddy, C. R.; Boehler, M.; Boek, J.; Boelaert, N.; Böser, S.; Bogaerts, J. A.; Bogdanchikov, A.; Bogouch, A.; Bohm, C.; Boisvert, V.; Bold, T.; Boldea, V.; Bolnet, N. M.; Bona, M.; Bondarenko, V. G.; Boonekamp, M.; Boorman, G.; Booth, C. N.; Booth, P.; Bordoni, S.; Borer, C.; Borisov, A.; Borissov, G.; Borjanovic, I.; Borroni, S.; Bos, K.; Boscherini, D.; Bosman, M.; Boterenbrood, H.; Botterill, D.; Bouchami, J.; Boudreau, J.; Bouhova-Thacker, E. V.; Boulahouache, C.; Bourdarios, C.; Bousson, N.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bozhko, N. I.; Bozovic-Jelisavcic, I.; Bracinik, J.; Braem, A.; Branchini, P.; Brandenburg, G. W.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Braun, H. M.; Brelier, B.; Bremer, J.; Brenner, R.; Bressler, S.; Breton, D.; Brett, N. D.; Britton, D.; Brochu, F. M.; Brock, I.; Brock, R.; Brodbeck, T. J.; Brodet, E.; Broggi, F.; Bromberg, C.; Brooijmans, G.; Brooks, W. K.; Brown, G.; Brubaker, E.; Bruckman de Renstrom, P. A.; Bruncko, D.; Bruneliere, R.; Brunet, S.; Bruni, A.; Bruni, G.; Bruschi, M.; Buanes, T.; Bucci, F.; Buchanan, J.; Buchanan, N. J.; Buchholz, P.; Buckingham, R. M.; Buckley, A. G.; Buda, S. I.; Budagov, I. A.; Budick, B.; Büscher, V.; Bugge, L.; Buira-Clark, D.; Buis, E. J.; Bulekov, O.; Bunse, M.; Buran, T.; Burckhart, H.; Burdin, S.; Burgess, T.; Burke, S.; Busato, E.; Bussey, P.; Buszello, C. P.; Butin, F.; Butler, B.; Butler, J. M.; Buttar, C. M.; Butterworth, J. M.; Buttinger, W.; Byatt, T.; Cabrera Urbán, S.; Caforio, D.; Cakir, O.; Calafiura, P.; Calderini, G.; Calfayan, P.; Calkins, R.; Caloba, L. P.; Caloi, R.; Calvet, D.; Calvet, S.; Camacho Toro, R.; Camard, A.; Camarri, P.; Cambiaghi, M.; Cameron, D.; Cammin, J.; Campana, S.; Campanelli, M.; Canale, V.; Canelli, F.; Canepa, A.; Cantero, J.; Capasso, L.; Capeans Garrido, M. D. M.; Caprini, I.; Caprini, M.; Capriotti, D.; Capua, M.; Caputo, R.; Caramarcu, C.; Cardarelli, R.; Carli, T.; Carlino, G.; Carminati, L.; Caron, B.; Caron, S.; Carpentieri, C.; Carrillo Montoya, G. D.; Carter, A. A.; Carter, J. R.; Carvalho, J.; Casadei, D.; Casado, M. P.; Cascella, M.; Caso, C.; Castaneda Hernandez, A. M.; Castaneda-Miranda, E.; Castillo Gimenez, V.; Castro, N. F.; Cataldi, G.; Cataneo, F.; Catinaccio, A.; Catmore, J. R.; Cattai, A.; Cattani, G.; Caughron, S.; Cauz, D.; Cavallari, A.; Cavalleri, P.; Cavalli, D.; Cavalli-Sforza, M.; Cavasinni, V.; Cazzato, A.; Ceradini, F.; Cerqueira, A. S.; Cerri, A.; Cerrito, L.; Cerutti, F.; Cetin, S. A.; Cevenini, F.; Chafaq, A.; Chakraborty, D.; Chan, K.; Chapleau, B.; Chapman, J. D.; Chapman, J. W.; Chareyre, E.; Charlton, D. G.; Chavda, V.; Cheatham, S.; Chekanov, S.; Chekulaev, S. V.; Chelkov, G. A.; Chelstowska, M. A.; Chen, C.; Chen, H.; Chen, L.; Chen, S.; Chen, T.; Chen, X.; Cheng, S.; Cheplakov, A.; Chepurnov, V. F.; Cherkaoui El Moursli, R.; Chernyatin, V.; Cheu, E.; Cheung, S. L.; Chevalier, L.; Chiefari, G.; Chikovani, L.; Childers, J. T.; Chilingarov, A.; Chiodini, G.; Chizhov, M. V.; Choudalakis, G.; Chouridou, S.; Christidi, I. A.; Christov, A.; Chromek-Burckhart, D.; Chu, M. L.; Chudoba, J.; Ciapetti, G.; Ciba, K.; Ciftci, A. K.; Ciftci, R.; Cinca, D.; Cindro, V.; Ciobotaru, M. D.; Ciocca, C.; Ciocio, A.; Cirilli, M.; Ciubancan, M.; Clark, A.; Clark, P. J.; Cleland, W.; Clemens, J. C.; Clement, B.; Clement, C.; Clifft, R. W.; Coadou, Y.; Cobal, M.; Coccaro, A.; Cochran, J.; Coe, P.; Cogan, J. G.; Coggeshall, J.; Cogneras, E.; Cojocaru, C. D.; Colas, J.; Colijn, A. P.; Collard, C.; Collins, N. J.; Collins-Tooth, C.; Collot, J.; Colon, G.; Comune, G.; Conde Muiño, P.; Coniavitis, E.; Conidi, M. C.; Consonni, M.; Constantinescu, S.; Conta, C.; Conventi, F.; Cook, J.; Cooke, M.; Cooper, B. D.; Cooper-Sarkar, A. M.; Cooper-Smith, N. J.; Copic, K.; Cornelissen, T.; Corradi, M.; Corriveau, F.; Cortes-Gonzalez, A.; Cortiana, G.; Costa, G.; Costa, M. J.; Costanzo, D.; Costin, T.; Côté, D.; Coura Torres, R.; Courneyea, L.; Cowan, G.; Cowden, C.; Cox, B. E.; Cranmer, K.; Crescioli, F.; Cristinziani, M.; Crosetti, G.; Crupi, R.; Crépé-Renaudin, S.; Cuenca Almenar, C.; Cuhadar Donszelmann, T.; Cuneo, S.; Curatolo, M.; Curtis, C. J.; Cwetanski, P.; Czirr, H.; Czyczula, Z.; D'Auria, S.; D'Onofrio, M.; D'Orazio, A.; da Rocha Gesualdi Mello, A.; da Silva, P. V. M.; da Via, C.; Dabrowski, W.; Dahlhoff, A.; Dai, T.; Dallapiccola, C.; Dallison, S. J.; Dam, M.; Dameri, M.; Damiani, D. S.; Danielsson, H. O.; Dankers, R.; Dannheim, D.; Dao, V.; Darbo, G.; Darlea, G. L.; Daum, C.; Dauvergne, J. P.; Davey, W.; Davidek, T.; Davidson, N.; Davidson, R.; Davies, M.; Davison, A. R.; Dawe, E.; Dawson, I.; Dawson, J. W.; Daya, R. K.; de, K.; de Asmundis, R.; de Castro, S.; de Castro Faria Salgado, P. E.; de Cecco, S.; de Graat, J.; de Groot, N.; de Jong, P.; de La Taille, C.; de la Torre, H.; de Lotto, B.; de Mora, L.; de Nooij, L.; de Oliveira Branco, M.; de Pedis, D.; de Saintignon, P.; de Salvo, A.; de Sanctis, U.; de Santo, A.; de Vivie de Regie, J. B.; Dean, S.; Dedovich, D. V.; Degenhardt, J.; Dehchar, M.; Deile, M.; Del Papa, C.; Del Peso, J.; Del Prete, T.; Dell'Acqua, A.; Dell'Asta, L.; Della Pietra, M.; Della Volpe, D.; Delmastro, M.; Delpierre, P.; Delruelle, N.; Delsart, P. A.; Deluca, C.; Demers, S.; Demichev, M.; Demirkoz, B.; Deng, J.; Denisov, S. P.; Derendarz, D.; Derkaoui, J. E.; Derue, F.; Dervan, P.; Desch, K.; Devetak, E.; Deviveiros, P. O.; Dewhurst, A.; Dewilde, B.; Dhaliwal, S.; Dhullipudi, R.; di Ciaccio, A.; di Ciaccio, L.; di Girolamo, A.; di Girolamo, B.; di Luise, S.; di Mattia, A.; di Micco, B.; di Nardo, R.; di Simone, A.; di Sipio, R.; Diaz, M. A.; Diblen, F.; Diehl, E. B.; Dietl, H.; Dietrich, J.; Dietzsch, T. A.; Diglio, S.; Dindar Yagci, K.; Dingfelder, J.; Dionisi, C.; Dita, P.; Dita, S.; Dittus, F.; Djama, F.; Djilkibaev, R.; Djobava, T.; Do Vale, M. A. B.; Do Valle Wemans, A.; Doan, T. K. O.; Dobbs, M.; Dobinson, R.; Dobos, D.; Dobson, E.; Dobson, M.; Dodd, J.; Dogan, O. B.; Doglioni, C.; Doherty, T.; Doi, Y.; Dolejsi, J.; Dolenc, I.; Dolezal, Z.; Dolgoshein, B. A.; Dohmae, T.; Donadelli, M.; Donega, M.; Donini, J.; Dopke, J.; Doria, A.; Dos Anjos, A.; Dosil, M.; Dotti, A.; Dova, M. T.; Dowell, J. D.; Doxiadis, A. D.; Doyle, A. T.; Drasal, Z.; Drees, J.; Dressnandt, N.; Drevermann, H.; Driouichi, C.; Dris, M.; Drohan, J. G.; Dubbert, J.; Dubbs, T.; Dube, S.; Duchovni, E.; Duckeck, G.; Dudarev, A.; Dudziak, F.; Dührssen, M.; Duerdoth, I. P.; Duflot, L.; Dufour, M.-A.; Dunford, M.; Duran Yildiz, H.; Duxfield, R.; Dwuznik, M.; Dydak, F.; Dzahini, D.; Düren, M.; Ebenstein, W. L.; Ebke, J.; Eckert, S.; Eckweiler, S.; Edmonds, K.; Edwards, C. A.; Ehrenfeld, W.; Ehrich, T.; Eifert, T.; Eigen, G.; Einsweiler, K.; Eisenhandler, E.; Ekelof, T.; El Kacimi, M.; Ellert, M.; Elles, S.; Ellinghaus, F.; Ellis, K.; Ellis, N.; Elmsheuser, J.; Elsing, M.; Ely, R.; Emeliyanov, D.; Engelmann, R.; Engl, A.; Epp, B.; Eppig, A.; Erdmann, J.; Ereditato, A.; Eriksson, D.; Ernst, J.; Ernst, M.; Ernwein, J.; Errede, D.; Errede, S.; Ertel, E.; Escalier, M.; Escobar, C.; Espinal Curull, X.; Esposito, B.; Etienne, F.; Etienvre, A. I.; Etzion, E.; Evangelakou, D.; Evans, H.; Fabbri, L.; Fabre, C.; Facius, K.; Fakhrutdinov, R. M.; Falciano, S.; Falou, A. C.; Fang, Y.; Fanti, M.; Farbin, A.; Farilla, A.; Farley, J.; Farooque, T.; Farrington, S. M.; Farthouat, P.; Fasching, D.; Fassnacht, P.; Fassouliotis, D.; Fatholahzadeh, B.; Favareto, A.; Fayard, L.; Fazio, S.; Febbraro, R.; Federic, P.; Fedin, O. L.; Fedorko, I.; Fedorko, W.; Fehling-Kaschek, M.; Feligioni, L.; Fellmann, D.; Felzmann, C. U.; Feng, C.; Feng, E. J.; Fenyuk, A. B.; Ferencei, J.; Ferland, J.; Fernandes, B.; Fernando, W.; Ferrag, S.; Ferrando, J.; Ferrara, V.; Ferrari, A.; Ferrari, P.; Ferrari, R.; Ferrer, A.; Ferrer, M. L.; Ferrere, D.; Ferretti, C.; Ferretto Parodi, A.; Fiascaris, M.; Fiedler, F.; Filipčič, A.; Filippas, A.; Filthaut, F.; Fincke-Keeler, M.; Fiolhais, M. C. N.; Fiorini, L.; Firan, A.; Fischer, G.; Fischer, P.; Fisher, M. J.; Fisher, S. M.; Flammer, J.; Flechl, M.; Fleck, I.; Fleckner, J.; Fleischmann, P.; Fleischmann, S.; Flick, T.; Flores Castillo, L. R.; Flowerdew, M. J.; Föhlisch, F.; Fokitis, M.; Fonseca Martin, T.; Forbush, D. A.; Formica, A.; Forti, A.; Fortin, D.; Foster, J. M.; Fournier, D.; Foussat, A.; Fowler, A. J.; Fowler, K.; Fox, H.; Francavilla, P.; Franchino, S.; Francis, D.; Frank, T.; Franklin, M.; Franz, S.; Fraternali, M.; Fratina, S.; French, S. T.; Froeschl, R.; Froidevaux, D.; Frost, J. A.; Fukunaga, C.; Fullana Torregrosa, E.; Fuster, J.; Gabaldon, C.; Gabizon, O.; Gadfort, T.; Gadomski, S.; Gagliardi, G.; Gagnon, P.; Galea, C.; Gallas, E. J.; Gallas, M. V.; Gallo, V.; Gallop, B. J.; Gallus, P.; Galyaev, E.; Gan, K. K.; Gao, Y. S.; Gapienko, V. A.; Gaponenko, A.; Garberson, F.; Garcia-Sciveres, M.; García, C.; García Navarro, J. E.; Gardner, R. W.; Garelli, N.; Garitaonandia, H.; Garonne, V.; Garvey, J.; Gatti, C.; Gaudio, G.; Gaumer, O.; Gaur, B.; Gauthier, L.; Gavrilenko, I. L.; Gay, C.; Gaycken, G.; Gayde, J.-C.; Gazis, E. N.; Ge, P.; Gee, C. N. P.; Geerts, D. A. A.; Geich-Gimbel, Ch.; Gellerstedt, K.; Gemme, C.; Gemmell, A.; Genest, M. H.; Gentile, S.; George, M.; George, S.; Gerlach, P.; Gershon, A.; Geweniger, C.; Ghazlane, H.; Ghez, P.; Ghodbane, N.; Giacobbe, B.; Giagu, S.; Giakoumopoulou, V.; Giangiobbe, V.; Gianotti, F.; Gibbard, B.; Gibson, A.; Gibson, S. M.; Gieraltowski, G. F.; Gilbert, L. M.; Gilchriese, M.; Gilewsky, V.; Gillberg, D.; Gillman, A. 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B.; Nicolaidou, R.; Nicolas, L.; Nicquevert, B.; Niedercorn, F.; Nielsen, J.; Niinikoski, T.; Nikiforov, A.; Nikolaenko, V.; Nikolaev, K.; Nikolic-Audit, I.; Nikolopoulos, K.; Nilsen, H.; Nilsson, P.; Ninomiya, Y.; Nisati, A.; Nishiyama, T.; Nisius, R.; Nodulman, L.; Nomachi, M.; Nomidis, I.; Nomoto, H.; Nordberg, M.; Nordkvist, B.; Norton, P. R.; Novakova, J.; Nozaki, M.; Nožička, M.; Nozka, L.; Nugent, I. M.; Nuncio-Quiroz, A.-E.; Nunes Hanninger, G.; Nunnemann, T.; Nurse, E.; Nyman, T.; O'Brien, B. J.; O'Neale, S. W.; O'Neil, D. C.; O'Shea, V.; Oakham, F. G.; Oberlack, H.; Ocariz, J.; Ochi, A.; Oda, S.; Odaka, S.; Odier, J.; Ogren, H.; Oh, A.; Oh, S. H.; Ohm, C. C.; Ohshima, T.; Ohshita, H.; Ohska, T. K.; Ohsugi, T.; Okada, S.; Okawa, H.; Okumura, Y.; Okuyama, T.; Olcese, M.; Olchevski, A. G.; Oliveira, M.; Oliveira Damazio, D.; Oliver Garcia, E.; Olivito, D.; Olszewski, A.; Olszowska, J.; Omachi, C.; Onofre, A.; Onyisi, P. U. E.; Oram, C. J.; Oreglia, M. 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T.; Perez Reale, V.; Peric, I.; Perini, L.; Pernegger, H.; Perrino, R.; Perrodo, P.; Persembe, S.; Peshekhonov, V. D.; Peters, O.; Petersen, B. A.; Petersen, J.; Petersen, T. C.; Petit, E.; Petridis, A.; Petridou, C.; Petrolo, E.; Petrucci, F.; Petschull, D.; Petteni, M.; Pezoa, R.; Phan, A.; Phillips, A. W.; Phillips, P. W.; Piacquadio, G.; Piccaro, E.; Piccinini, M.; Pickford, A.; Piec, S. M.; Piegaia, R.; Pilcher, J. E.; Pilkington, A. D.; Pina, J.; Pinamonti, M.; Pinder, A.; Pinfold, J. L.; Ping, J.; Pinto, B.; Pirotte, O.; Pizio, C.; Placakyte, R.; Plamondon, M.; Plano, W. G.; Pleier, M.-A.; Pleskach, A. V.; Poblaguev, A.; Poddar, S.; Podlyski, F.; Poggioli, L.; Poghosyan, T.; Pohl, M.; Polci, F.; Polesello, G.; Policicchio, A.; Polini, A.; Poll, J.; Polychronakos, V.; Pomarede, D. M.; Pomeroy, D.; Pommès, K.; Pontecorvo, L.; Pope, B. G.; Popeneciu, G. A.; Popovic, D. S.; Poppleton, A.; Portell Bueso, X.; Porter, R.; Posch, C.; Pospelov, G. E.; Pospisil, S.; Potrap, I. N.; Potter, C. J.; Potter, C. T.; Poulard, G.; Poveda, J.; Prabhu, R.; Pralavorio, P.; Prasad, S.; Pravahan, R.; Prell, S.; Pretzl, K.; Pribyl, L.; Price, D.; Price, L. E.; Price, M. J.; Prichard, P. M.; Prieur, D.; Primavera, M.; Prokofiev, K.; Prokoshin, F.; Protopopescu, S.; Proudfoot, J.; Prudent, X.; Przysiezniak, H.; Psoroulas, S.; Ptacek, E.; Purdham, J.; Purohit, M.; Puzo, P.; Pylypchenko, Y.; Qian, J.; Qian, Z.; Qin, Z.; Quadt, A.; Quarrie, D. R.; Quayle, W. B.; Quinonez, F.; Raas, M.; Radescu, V.; Radics, B.; Rador, T.; Ragusa, F.; Rahal, G.; Rahimi, A. M.; Rahm, D.; Rajagopalan, S.; Rammensee, M.; Rammes, M.; Ramstedt, M.; Randrianarivony, K.; Ratoff, P. N.; Rauscher, F.; Rauter, E.; Raymond, M.; Read, A. L.; Rebuzzi, D. M.; Redelbach, A.; Redlinger, G.; Reece, R.; Reeves, K.; Reichold, A.; Reinherz-Aronis, E.; Reinsch, A.; Reisinger, I.; Reljic, D.; Rembser, C.; Ren, Z. L.; Renaud, A.; Renkel, P.; Rensch, B.; Rescigno, M.; Resconi, S.; Resende, B.; Reznicek, P.; Rezvani, R.; Richards, A.; Richter, R.; Richter-Was, E.; Ridel, M.; Rieke, S.; Rijpstra, M.; Rijssenbeek, M.; Rimoldi, A.; Rinaldi, L.; Rios, R. R.; Riu, I.; Rivoltella, G.; Rizatdinova, F.; Rizvi, E.; Robertson, S. H.; Robichaud-Veronneau, A.; Robinson, D.; Robinson, J. E. M.; Robinson, M.; Robson, A.; Rocha de Lima, J. G.; Roda, C.; Roda Dos Santos, D.; Rodier, S.; Rodriguez, D.; Rodriguez Garcia, Y.; Roe, A.; Roe, S.; Røhne, O.; Rojo, V.; Rolli, S.; Romaniouk, A.; Romanov, V. M.; Romeo, G.; Romero Maltrana, D.; Roos, L.; Ros, E.; Rosati, S.; Rose, M.; Rosenbaum, G. A.; Rosenberg, E. I.; Rosendahl, P. L.; Rosselet, L.; Rossetti, V.; Rossi, E.; Rossi, L. P.; Rossi, L.; Rotaru, M.; Roth, I.; Rothberg, J.; Rousseau, D.; Royon, C. R.; Rozanov, A.; Rozen, Y.; Ruan, X.; Rubinskiy, I.; Ruckert, B.; Ruckstuhl, N.; Rud, V. I.; Rudolph, G.; Rühr, F.; Ruggieri, F.; Ruiz-Martinez, A.; Rulikowska-Zarebska, E.; Rumiantsev, V.; Rumyantsev, L.; Runge, K.; Runolfsson, O.; Rurikova, Z.; Rusakovich, N. A.; Rust, D. R.; Rutherfoord, J. P.; Ruwiedel, C.; Ruzicka, P.; Ryabov, Y. F.; Ryadovikov, V.; Ryan, P.; Rybar, M.; Rybkin, G.; Ryder, N. C.; Rzaeva, S.; Saavedra, A. F.; Sadeh, I.; Sadrozinski, H. F.-W.; Sadykov, R.; Safai Tehrani, F.; Sakamoto, H.; Salamanna, G.; Salamon, A.; Saleem, M.; Salihagic, D.; Salnikov, A.; Salt, J.; Salvachua Ferrando, B. M.; Salvatore, D.; Salvatore, F.; Salzburger, A.; Sampsonidis, D.; Samset, B. H.; Sandaker, H.; Sander, H. G.; Sanders, M. P.; Sandhoff, M.; Sandhu, P.; Sandoval, T.; Sandstroem, R.; Sandvoss, S.; Sankey, D. P. C.; Sansoni, A.; Santamarina Rios, C.; Santoni, C.; Santonico, R.; Santos, H.; Saraiva, J. G.; Sarangi, T.; Sarkisyan-Grinbaum, E.; Sarri, F.; Sartisohn, G.; Sasaki, O.; Sasaki, T.; Sasao, N.; Satsounkevitch, I.; Sauvage, G.; Sauvan, J. B.; Savard, P.; Savinov, V.; Savu, D. O.; Savva, P.; Sawyer, L.; Saxon, D. H.; Says, L. P.; Sbarra, C.; Sbrizzi, A.; Scallon, O.; Scannicchio, D. A.; Schaarschmidt, J.; Schacht, P.; Schäfer, U.; Schaepe, S.; Schaetzel, S.; Schaffer, A. C.; Schaile, D.; Schamberger, R. D.; Schamov, A. G.; Scharf, V.; Schegelsky, V. A.; Scheirich, D.; Scherzer, M. I.; Schiavi, C.; Schieck, J.; Schioppa, M.; Schlenker, S.; Schlereth, J. L.; Schmidt, E.; Schmidt, M. P.; Schmieden, K.; Schmitt, C.; Schmitz, M.; Schöning, A.; Schott, M.; Schouten, D.; Schovancova, J.; Schram, M.; Schroeder, C.; Schroer, N.; Schuh, S.; Schuler, G.; Schultes, J.; Schultz-Coulon, H.-C.; Schulz, H.; Schumacher, J. W.; Schumacher, M.; Schumm, B. A.; Schune, Ph.; Schwanenberger, C.; Schwartzman, A.; Schwemling, Ph.; Schwienhorst, R.; Schwierz, R.; Schwindling, J.; Scott, W. G.; Searcy, J.; Sedykh, E.; Segura, E.; Seidel, S. C.; Seiden, A.; Seifert, F.; Seixas, J. M.; Sekhniaidze, G.; Seliverstov, D. M.; Sellden, B.; Sellers, G.; Seman, M.; Semprini-Cesari, N.; Serfon, C.; Serin, L.; Seuster, R.; Severini, H.; Sevior, M. E.; Sfyrla, A.; Shabalina, E.; Shamim, M.; Shan, L. Y.; Shank, J. T.; Shao, Q. T.; Shapiro, M.; Shatalov, P. B.; Shaver, L.; Shaw, C.; Shaw, K.; Sherman, D.; Sherwood, P.; Shibata, A.; Shimizu, S.; Shimojima, M.; Shin, T.; Shmeleva, A.; Shochet, M. J.; Short, D.; Shupe, M. A.; Sicho, P.; Sidoti, A.; Siebel, A.; Siegert, F.; Siegrist, J.; Sijacki, Dj.; Silbert, O.; Silva, J.; Silver, Y.; Silverstein, D.; Silverstein, S. B.; Simak, V.; Simard, O.; Simic, Lj.; Simion, S.; Simmons, B.; Simonyan, M.; Sinervo, P.; Sinev, N. B.; Sipica, V.; Siragusa, G.; Sisakyan, A. N.; Sivoklokov, S. Yu.; Sjölin, J.; Sjursen, T. B.; Skinnari, L. A.; Skovpen, K.; Skubic, P.; Skvorodnev, N.; Slater, M.; Slavicek, T.; Sliwa, K.; Sloan, T. J.; Sloper, J.; Smakhtin, V.; Smirnov, S. Yu.; Smirnova, L. N.; Smirnova, O.; Smith, B. C.; Smith, D.; Smith, K. M.; Smizanska, M.; Smolek, K.; Snesarev, A. A.; Snow, S. W.; Snow, J.; Snuverink, J.; Snyder, S.; Soares, M.; Sobie, R.; Sodomka, J.; Soffer, A.; Solans, C. A.; Solar, M.; Solc, J.; Soldatov, E.; Soldevila, U.; Solfaroli Camillocci, E.; Solodkov, A. A.; Solovyanov, O. V.; Sondericker, J.; Soni, N.; Sopko, V.; Sopko, B.; Sorbi, M.; Sosebee, M.; Soukharev, A.; Spagnolo, S.; Spanò, F.; Spighi, R.; Spigo, G.; Spila, F.; Spiriti, E.; Spiwoks, R.; Spousta, M.; Spreitzer, T.; Spurlock, B.; St. Denis, R. D.; Stahl, T.; Stahlman, J.; Stamen, R.; Stanecka, E.; Stanek, R. W.; Stanescu, C.; Stapnes, S.; Starchenko, E. A.; Stark, J.; Staroba, P.; Starovoitov, P.; Staude, A.; Stavina, P.; Stavropoulos, G.; Steele, G.; Steinbach, P.; Steinberg, P.; Stekl, I.; Stelzer, B.; Stelzer, H. J.; Stelzer-Chilton, O.; Stenzel, H.; Stevenson, K.; Stewart, G. A.; Stillings, J. A.; Stockmanns, T.; Stockton, M. C.; Stoerig, K.; Stoicea, G.; Stonjek, S.; Strachota, P.; Stradling, A. R.; Straessner, A.; Strandberg, J.; Strandberg, S.; Strandlie, A.; Strang, M.; Strauss, E.; Strauss, M.; Strizenec, P.; Ströhmer, R.; Strom, D. M.; Strong, J. A.; Stroynowski, R.; Strube, J.; Stugu, B.; Stumer, I.; Stupak, J.; Sturm, P.; Soh, D. A.; Su, D.; Subramania, H. S.; Succurro, A.; Sugaya, Y.; Sugimoto, T.; Suhr, C.; Suita, K.; Suk, M.; Sulin, V. V.; Sultansoy, S.; Sumida, T.; Sun, X.; Sundermann, J. E.; Suruliz, K.; Sushkov, S.; Susinno, G.; Sutton, M. R.; Suzuki, Y.; Sviridov, Yu. M.; Swedish, S.; Sykora, I.; Sykora, T.; Szeless, B.; Sánchez, J.; Ta, D.; Tackmann, K.; Taffard, A.; Tafirout, R.; Taga, A.; Taiblum, N.; Takahashi, Y.; Takai, H.; Takashima, R.; Takeda, H.; Takeshita, T.; Talby, M.; Talyshev, A.; Tamsett, M. C.; Tanaka, J.; Tanaka, R.; Tanaka, S.; Tanaka, S.; Tanaka, Y.; Tani, K.; Tannoury, N.; Tappern, G. P.; Tapprogge, S.; Tardif, D.; Tarem, S.; Tarrade, F.; Tartarelli, G. F.; Tas, P.; Tasevsky, M.; Tassi, E.; Tatarkhanov, M.; Taylor, C.; Taylor, F. E.; Taylor, G. N.; Taylor, W.; Teixeira Dias Castanheira, M.; Teixeira-Dias, P.; Temming, K. K.; Ten Kate, H.; Teng, P. K.; Terada, S.; Terashi, K.; Terron, J.; Terwort, M.; Testa, M.; Teuscher, R. J.; Tevlin, C. M.; Thadome, J.; Therhaag, J.; Theveneaux-Pelzer, T.; Thioye, M.; Thoma, S.; Thomas, J. P.; Thompson, E. N.; Thompson, P. D.; Thompson, P. D.; Thompson, A. S.; Thomson, E.; Thomson, M.; Thun, R. P.; Tic, T.; Tikhomirov, V. O.; Tikhonov, Y. A.; Timmermans, C. J. W. P.; Tipton, P.; Tique Aires Viegas, F. J.; Tisserant, S.; Tobias, J.; Toczek, B.; Todorov, T.; Todorova-Nova, S.; Toggerson, B.; Tojo, J.; Tokár, S.; Tokunaga, K.; Tokushuku, K.; Tollefson, K.; Tomoto, M.; Tompkins, L.; Toms, K.; Tong, G.; Tonoyan, A.; Topfel, C.; Topilin, N. D.; Torchiani, I.; Torrence, E.; Torró Pastor, E.; Toth, J.; Touchard, F.; Tovey, D. R.; Traynor, D.; Trefzger, T.; Treis, J.; Tremblet, L.; Tricoli, A.; Trigger, I. M.; Trincaz-Duvoid, S.; Trinh, T. N.; Tripiana, M. F.; Triplett, N.; Trischuk, W.; Trivedi, A.; Trocmé, B.; Troncon, C.; Trottier-McDonald, M.; Trzupek, A.; Tsarouchas, C.; Tseng, J. C.-L.; Tsiakiris, M.; Tsiareshka, P. V.; Tsionou, D.; Tsipolitis, G.; Tsiskaridze, V.; Tskhadadze, E. G.; Tsukerman, I. I.; Tsulaia, V.; Tsung, J.-W.; Tsuno, S.; Tsybychev, D.; Tua, A.; Tuggle, J. M.; Turala, M.; Turecek, D.; Turk Cakir, I.; Turlay, E.; Turra, R.; Tuts, P. M.; Tykhonov, A.; Tylmad, M.; Tyndel, M.; Tyrvainen, H.; Tzanakos, G.; Uchida, K.; Ueda, I.; Ueno, R.; Ugland, M.; Uhlenbrock, M.; Uhrmacher, M.; Ukegawa, F.; Unal, G.; Underwood, D. G.; Undrus, A.; Unel, G.; Unno, Y.; Urbaniec, D.; Urkovsky, E.; Urrejola, P.; Usai, G.; Uslenghi, M.; Vacavant, L.; Vacek, V.; Vachon, B.; Vahsen, S.; Valderanis, C.; Valenta, J.; Valente, P.; Valentinetti, S.; Valkar, S.; Valladolid Gallego, E.; Vallecorsa, S.; Valls Ferrer, J. A.; van der Graaf, H.; van der Kraaij, E.; van der Leeuw, R.; van der Poel, E.; van der Ster, D.; van Eijk, B.; van Eldik, N.; van Gemmeren, P.; van Kesteren, Z.; van Vulpen, I.; Vandelli, W.; Vandoni, G.; Vaniachine, A.; Vankov, P.; Vannucci, F.; Varela Rodriguez, F.; Vari, R.; Varnes, E. W.; Varouchas, D.; Vartapetian, A.; Varvell, K. E.; Vassilakopoulos, V. I.; Vazeille, F.; Vegni, G.; Veillet, J. J.; Vellidis, C.; Veloso, F.; Veness, R.; Veneziano, S.; Ventura, A.; Ventura, D.; Venturi, M.; Venturi, N.; Vercesi, V.; Verducci, M.; Verkerke, W.; Vermeulen, J. C.; Vest, A.; Vetterli, M. C.; Vichou, I.; Vickey, T.; Viehhauser, G. H. A.; Viel, S.; Villa, M.; Villaplana Perez, M.; Vilucchi, E.; Vincter, M. G.; Vinek, E.; Vinogradov, V. B.; Virchaux, M.; Viret, S.; Virzi, J.; Vitale, A.; Vitells, O.; Viti, M.; Vivarelli, I.; Vives Vaque, F.; Vlachos, S.; Vlasak, M.; Vlasov, N.; Vogel, A.; Vokac, P.; Volpi, G.; Volpi, M.; Volpini, G.; von der Schmitt, H.; von Loeben, J.; von Radziewski, H.; von Toerne, E.; Vorobel, V.; Vorobiev, A. P.; Vorwerk, V.; Vos, M.; Voss, R.; Voss, T. T.; Vossebeld, J. H.; Vovenko, A. S.; Vranjes, N.; Vranjes Milosavljevic, M.; Vrba, V.; Vreeswijk, M.; Vu Anh, T.; Vuillermet, R.; Vukotic, I.; Wagner, W.; Wagner, P.; Wahlen, H.; Wakabayashi, J.; Walbersloh, J.; Walch, S.; Walder, J.; Walker, R.; Walkowiak, W.; Wall, R.; Waller, P.; Wang, C.; Wang, H.; Wang, H.; Wang, J.; Wang, J.; Wang, J. C.; Wang, R.; Wang, S. M.; Warburton, A.; Ward, C. P.; Warsinsky, M.; Watkins, P. M.; Watson, A. T.; Watson, M. F.; Watts, G.; Watts, S.; Waugh, A. T.; Waugh, B. M.; Weber, J.; Weber, M.; Weber, M. S.; Weber, P.; Weidberg, A. R.; Weigell, P.; Weingarten, J.; Weiser, C.; Wellenstein, H.; Wells, P. S.; Wen, M.; Wenaus, T.; Wendler, S.; Weng, Z.; Wengler, T.; Wenig, S.; Wermes, N.; Werner, M.; Werner, P.; Werth, M.; Wessels, M.; Whalen, K.; Wheeler-Ellis, S. J.; Whitaker, S. P.; White, A.; White, M. J.; White, S.; Whitehead, S. R.; Whiteson, D.; Whittington, D.; Wicek, F.; Wicke, D.; Wickens, F. J.; Wiedenmann, W.; Wielers, M.; Wienemann, P.; Wiglesworth, C.; Wiik, L. A. M.; Wijeratne, P. A.; Wildauer, A.; Wildt, M. A.; Wilhelm, I.; Wilkens, H. G.; Will, J. Z.; Williams, E.; Williams, H. H.; Willis, W.; Willocq, S.; Wilson, J. A.; Wilson, M. G.; Wilson, A.; Wingerter-Seez, I.; Winkelmann, S.; Winklmeier, F.; Wittgen, M.; Wolter, M. W.; Wolters, H.; Wooden, G.; Wosiek, B. K.; Wotschack, J.; Woudstra, M. J.; Wraight, K.; Wright, C.; Wrona, B.; Wu, S. L.; Wu, X.; Wu, Y.; Wulf, E.; Wunstorf, R.; Wynne, B. M.; Xaplanteris, L.; Xella, S.; Xie, S.; Xie, Y.; Xu, C.; Xu, D.; Xu, G.; Yabsley, B.; Yamada, M.; Yamamoto, A.; Yamamoto, K.; Yamamoto, S.; Yamamura, T.; Yamaoka, J.; Yamazaki, T.; Yamazaki, Y.; Yan, Z.; Yang, H.; Yang, U. K.; Yang, Y.; Yang, Y.; Yang, Z.; Yanush, S.; Yao, W.-M.; Yao, Y.; Yasu, Y.; Ybeles Smit, G. V.; Ye, J.; Ye, S.; Yilmaz, M.; Yoosoofmiya, R.; Yorita, K.; Yoshida, R.; Young, C.; Youssef, S.; Yu, D.; Yu, J.; Yu, J.; Yuan, L.; Yurkewicz, A.; Zaets, V. G.; Zaidan, R.; Zaitsev, A. M.; Zajacova, Z.; Zalite, Yo. K.; Zanello, L.; Zarzhitsky, P.; Zaytsev, A.; Zeitnitz, C.; Zeller, M.; Zema, P. F.; Zemla, A.; Zendler, C.; Zenin, A. V.; Zenin, O.; Ženiš, T.; Zenonos, Z.; Zenz, S.; Zerwas, D.; Zevi Della Porta, G.; Zhan, Z.; Zhang, D.; Zhang, H.; Zhang, J.; Zhang, X.; Zhang, Z.; Zhao, L.; Zhao, T.; Zhao, Z.; Zhemchugov, A.; Zheng, S.; Zhong, J.; Zhou, B.; Zhou, N.; Zhou, Y.; Zhu, C. G.; Zhu, H.; Zhu, Y.; Zhuang, X.; Zhuravlov, V.; Zieminska, D.; Zimmermann, R.; Zimmermann, S.; Zimmermann, S.; Ziolkowski, M.; Zitoun, R.; Živković, L.; Zmouchko, V. V.; Zobernig, G.; Zoccoli, A.; Zolnierowski, Y.; Zsenei, A.; Zur Nedden, M.; Zutshi, V.; Zwalinski, L.; Atlas Collaboration

    2011-06-01

    This Letter presents a search for high mass e+e- or μ+μ- resonances in pp collisions at √{ s} = 7 TeV at the LHC. The data were recorded by the ATLAS experiment during 2010 and correspond to a total integrated luminosity of ∼ 40pb-1. No statistically significant excess above the Standard Model expectation is observed in the search region of dilepton invariant mass above 110 GeV. Upper limits at the 95% confidence level are set on the cross section times branching ratio of Z‧ resonances decaying to dielectrons and dimuons as a function of the resonance mass. A lower mass limit of 1.048 TeV on the Sequential Standard Model Z‧ boson is derived, as well as mass limits on Z* and E6-motivated Z‧ models.

  3. Blood-Brain Barrier Experiments with Clinical Magnetic Resonance Imaging and an Immunohistochemical Study

    PubMed Central

    Park, Jun Woo; Kim, Hak Jin; Han, Hyung Soo

    2010-01-01

    Objective The purpose of study was to evaluate the feasibility of brain magnetic resonance (MR) images of the rat obtained using a 1.5T MR machine in several blood-brain barrier (BBB) experiments. Methods Male Sprague-Dawley rats were used. MR images were obtained using a clinical 1.5T MR machine. A microcatheter was introduced via the femoral artery to the carotid artery. Normal saline (group 1, n = 4), clotted autologous blood (group 2, n = 4), triolein emulsion (group 3, n = 4), and oleic acid emulsion (group 4, n = 4) were infused into the carotid artery through a microcatheter. Conventional and diffusion-weighted images, the apparent coefficient map, perfusion-weighted images, and contrast-enhanced MR images were obtained. Brain tissue was obtained and triphenyltetrazolium chloride (TTC) staining was performed in group 2. Fluorescein isothiocyanate (FITC)-labeled dextran images and endothelial barrier antigen (EBA) studies were performed in group 4. Results The MR images in group 1 were of good quality. The MR images in group 2 revealed typical findings of acute cerebral infarction. Perfusion defects were noted on the perfusion-weighted images. The MR images in group 3 showed vasogenic edema and contrast enhancement, representing vascular damage. The rats in group 4 had vasogenic edema on the MR images and leakage of dextran on the FITC-labeled dextran image, representing increased vascular permeability. The immune reaction was decreased on the EBA study. Conclusion Clinical 1.5T MR images using a rat depicted many informative results in the present study. These results can be used in further researches of the BBB using combined clinical MR machines and immunohistochemical examinations. PMID:20379473

  4. (13)C-detected NMR experiments for automatic resonance assignment of IDPs and multiple-fixing SMFT processing.

    PubMed

    Dziekański, Paweł; Grudziąż, Katarzyna; Jarvoll, Patrik; Koźmiński, Wiktor; Zawadzka-Kazimierczuk, Anna

    2015-06-01

    Intrinsically disordered proteins (IDPs) have recently attracted much interest, due to their role in many biological processes, including signaling and regulation mechanisms. High-dimensional (13)C direct-detected NMR experiments have proven exceptionally useful in case of IDPs, providing spectra with superior peak dispersion. Here, two such novel experiments recorded with non-uniform sampling are introduced, these are 5D HabCabCO(CA)NCO and 5D HNCO(CA)NCO. Together with the 4D (HACA)CON(CA)NCO, an extension of the previously published 3D experiments (Pantoja-Uceda and Santoro in J Biomol NMR 59:43-50, 2014. doi: 10.1007/s10858-014-9827-1), they form a set allowing for complete and reliable resonance assignment of difficult IDPs. The processing is performed with sparse multidimensional Fourier transform based on the concept of restricting (fixing) some of spectral dimensions to a priori known resonance frequencies. In our study, a multiple-fixing method was developed, that allows easy access to spectral data. The experiments were tested on a resolution-demanding alpha-synuclein sample. Due to superior peak dispersion in high-dimensional spectrum and availability of the sequential connectivities between four consecutive residues, the overwhelming majority of resonances could be assigned automatically using the TSAR program. PMID:25902761

  5. Sapphire hard X-ray Fabry-Perot resonators for synchrotron experiments.

    PubMed

    Tsai, Yi Wei; Wu, Yu Hsin; Chang, Ying Yi; Liu, Wen Chung; Liu, Hong Lin; Chu, Chia Hong; Chen, Pei Chi; Lin, Pao Te; Fu, Chien Chung; Chang, Shih Lin

    2016-05-01

    Hard X-ray Fabry-Perot resonators (FPRs) made from sapphire crystals were constructed and characterized. The FPRs consisted of two crystal plates, part of a monolithic crystal structure of Al2O3, acting as a pair of mirrors, for the backward reflection (0 0 0 30) of hard X-rays at 14.3147 keV. The dimensional accuracy during manufacturing and the defect density in the crystal in relation to the resonance efficiency of sapphire FPRs were analyzed from a theoretical standpoint based on X-ray cavity resonance and measurements using scanning electron microscopic and X-ray topographic techniques for crystal defects. Well defined resonance spectra of sapphire FPRs were successfully obtained, and were comparable with the theoretical predictions. PMID:27140144

  6. The resonant X-ray diffraction in Co-Akermanite: Theory and experiment

    SciTech Connect

    Bindi, L.; Dmitrienko, V. E.; Ovchinnikova, E. N.; Soedzhima, Yu.

    2006-12-15

    The structural factors for X-ray resonant diffraction near the K-absorption edge of cobalt in Co-akermanite have been calculated with allowance for the known data about its incommensurate 2D modulation. It is shown that the local symmetry of Co atoms in the basic structure does not allow any pure resonant reflections in the dipole-dipole approximation. However, pure resonant reflections of the h00 (h = 2n + 1) type are possible owing to the dipole-quadrupole contribution. The 5D formalism is used for the incommensurately modulated structure. It is shown that the displacement terms in the anisotropic tensor atomic factors could mainly contribute to the first-order satellites, providing pure resonant satellite reflections of the hhlm0 (m = 2n + 1) or h00mm-bar (h = 2n + 1) types.

  7. Nuclear magnetic and quadrupole resonance in metallic powders in the presence of strong quadrupole interaction: Rhenium metal

    SciTech Connect

    Dimitropoulos, C.; Maglione, M.; Borsa, F.

    1988-03-01

    The nuclear-magnetic-resonance and nuclear-quadrupole-resonance (NQR-NMR) spectra of /sup 187/Re and /sup 185/Re in a powder of rhenium metal were measured in the temperature range 5--10 K both in zero field and with an external magnetic field. The zero-field NQR spectrum is severely broadened by a nonuniform distribution of quadrupole interactions. The average quadrupole coupling frequencies measured at 5 K are, for the two isotopes, ..nu../sub Q/ = 39 +- 0.2 MHz (/sup 187/Re) and ..nu../sub Q/ = 40.8 +- 0.3 MHz (/sup 185/Re). The spectra obtained in the presence of an external magnetic field can be interpreted satisfactorily in terms of transitions among the eigenstates of the full Hamiltonian (Zeeman plus quadrupolar). Measurements of relaxation rates yield T/sub 1/T = 0.03 sK, indicating a relaxation mechanism driven by the hyperfine interaction with the conduction electrons. The feasibility of NQR-NMR studies in small metal particles in the presence of strong inhomogeneous quadrupole interactions is assessed

  8. 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.

  9. Using nitrogen-14 nuclear quadrupole resonance and electric field gradient information for the study of radiation effects

    SciTech Connect

    Iselin, L.H.

    1995-12-01

    Nitrogen-14 nuclear quadrupole resonance (NQR) was used in an attempt to detect the effects of ionizing radiation on organic material. Previously reported resonances for urea were detected at 2,913.32 {+-} 0.01 kHz and 2,347.88 {+-} 0.08 kHz with associated T{sub 2}* values 780 {+-} 20 {micro}s and 523 {+-} 24 {micro}s, respectively. The previously unreported {nu}{sub {minus}} line for urea-d{sup 4} was detected at 2,381 {+-} 0.04 Khz and used to determine accurately for the first time the values for the nuclear quadrupole coupling constant {chi} (3,548.74 {+-} 0.03 kHz) and the asymmetry parameter {eta} (0.31571 {+-} 0.00007) for urea-d{sup 4}. The inverse linewidth parameter T{sub 2}* for {nu}{sub +} was measured at 928 {+-} 23 {micro}s and for {nu}{sub {minus}} at 721 {+-} 12 {micro}s. Townes and Dailey analysis was performed and urea-d{sup 4} exhibits a 0.004 increase in lone pair electronic density and a slight decrease in N-H bond electronic density, as compared to urea, probably due to the mass difference. A relationship is proposed, referred to as NQR linewidth analysis, between the dynamic spin relaxation times T{sub 2} and T{sub 2}* and the widths of the distributions of the NQR parameters. Linewidth analysis is presented as a tool for possible use in future NQR work in all area, not just radiation effects. This relationship is tested using sodium nitrite T{sub 2} and T{sub 2}* values for {nu}{sub {minus}} and {nu}{sub {minus}} as a function of temperature.

  10. Theory and experiment on resonant frequencies of liquid-air interfaces trapped in microfluidic devices

    NASA Astrophysics Data System (ADS)

    Chindam, Chandraprakash; Nama, Nitesh; Ian Lapsley, Michael; Costanzo, Francesco; Jun Huang, Tony

    2013-11-01

    Bubble-based microfluidic devices have been proven to be useful for many biological and chemical studies. These bubble-based microdevices are particularly useful when operated at the trapped bubbles' resonance frequencies. In this work, we present an analytical expression that can be used to predict the resonant frequency of a bubble trapped over an arbitrary shape. Also, the effect of viscosity on the dispersion characteristics of trapped bubbles is determined. A good agreement between experimental data and theoretical results is observed for resonant frequency of bubbles trapped over different-sized rectangular-shaped structures, indicating that our expression can be valuable in determining optimized operational parameters for many bubble-based microfluidic devices. Furthermore, we provide a close estimate for the harmonics and a method to determine the dispersion characteristics of a bubble trapped over circular shapes. Finally, we present a new method to predict fluid properties in microfluidic devices and complement the explanation of acoustic microstreaming.

  11. Resonance effects in elastic cross sections for electron scattering on pyrimidine: Experiment and theory

    NASA Astrophysics Data System (ADS)

    Regeta, Khrystyna; Allan, Michael; Winstead, Carl; McKoy, Vincent; Mašín, Zdeněk; Gorfinkiel, Jimena D.

    2016-01-01

    We measured differential cross sections for elastic (rotationally integrated) electron scattering on pyrimidine, both as a function of angle up to 180∘ at electron energies of 1, 5, 10, and 20 eV and as a function of electron energy in the range 0.1-14 eV. The experimental results are compared to the results of the fixed-nuclei Schwinger variational and R-matrix theoretical methods, which reproduce satisfactorily the magnitudes and shapes of the experimental cross sections. The emphasis of the present work is on recording detailed excitation functions revealing resonances in the excitation process. Resonant structures are observed at 0.2, 0.7, and 4.35 eV and calculations for different symmetries confirm their assignment as the X˜ 2A2, A˜ 2B1, and B˜ 2B1 shape resonances. As a consequence of superposition of coherent resonant amplitudes with background scattering the B˜ 2B1 shape resonance appears as a peak, a dip, or a step function in the cross sections recorded as a function of energy at different scattering angles and this effect is satisfactorily reproduced by theory. The dip and peak contributions at different scattering angles partially compensate, making the resonance nearly invisible in the integral cross section. Vibrationally integrated cross sections were also measured at 1, 5, 10 and 20 eV and the question of whether the fixed-nuclei cross sections should be compared to vibrationally elastic or vibrationally integrated cross section is discussed.

  12. Resonance effects in elastic cross sections for electron scattering on pyrimidine: Experiment and theory.

    PubMed

    Regeta, Khrystyna; Allan, Michael; Winstead, Carl; McKoy, Vincent; Mašín, Zdeněk; Gorfinkiel, Jimena D

    2016-01-14

    We measured differential cross sections for elastic (rotationally integrated) electron scattering on pyrimidine, both as a function of angle up to 180(∘) at electron energies of 1, 5, 10, and 20 eV and as a function of electron energy in the range 0.1-14 eV. The experimental results are compared to the results of the fixed-nuclei Schwinger variational and R-matrix theoretical methods, which reproduce satisfactorily the magnitudes and shapes of the experimental cross sections. The emphasis of the present work is on recording detailed excitation functions revealing resonances in the excitation process. Resonant structures are observed at 0.2, 0.7, and 4.35 eV and calculations for different symmetries confirm their assignment as the X̃(2)A2, Ã(2)B1, and B̃(2)B1 shape resonances. As a consequence of superposition of coherent resonant amplitudes with background scattering the B̃(2)B1 shape resonance appears as a peak, a dip, or a step function in the cross sections recorded as a function of energy at different scattering angles and this effect is satisfactorily reproduced by theory. The dip and peak contributions at different scattering angles partially compensate, making the resonance nearly invisible in the integral cross section. Vibrationally integrated cross sections were also measured at 1, 5, 10 and 20 eV and the question of whether the fixed-nuclei cross sections should be compared to vibrationally elastic or vibrationally integrated cross section is discussed. PMID:26772565

  13. 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.

  14. Alfven resonance mode conversion in the Phaedrus-T current drive experiments: Modelling and density fluctuations measurements

    SciTech Connect

    Vukovic, M.; Harper, M.; Breun, R.; Wukitch, S.

    1995-12-31

    Current drive experiments on the Phaedrus-T tokamak performed with a low field side two-strap fast wave antenna at frequencies below {omega}{sub cH} show loop volt drops of up to 30% with strap phasing (0, {pi}/2). RF induced density fluctuations in the plasma core have also been observed with a microwave reflectometer. It is believed that they are caused by kinetic Alfven waves generated by mode conversion of fast waves at the Alfven resonance. Correlation of the observed density fluctuations with the magnitude of the {Delta}V{sub loop} suggest that the {Delta}V{sub loop} is attributable to current drive/heating due to mode converted kinetic Alfven waves. The toroidal cold plasma wave code LION is used to model the Alfven resonance mode conversion surfaces in the experiments while the cylindrical hot plasma kinetic wave code ISMENE is used to model the behavior of kinetic Alfven waves at the Alfven resonance location. Initial results obtained from limited density, magnetic field, antenna phase, and impurity scans show good agreement between the RF induced density fluctuations and the predicted behavior of the kinetic Alfven waves. Detailed comparisons between the density fluctuations and the code predictions are presented.

  15. An Accessible Two-Dimensional Solution Nuclear Magnetic Resonance Experiment on Human Ubiquitin

    ERIC Educational Resources Information Center

    Rovnyak, David; Thompson, Laura E.

    2005-01-01

    Solution-state nuclear magnetic resonance (NMR) is an invaluable tool in structural and molecular biology research, but may be underutilized in undergraduate laboratories because instrumentation for performing structural studies of macromolecules in aqueous solutions is not yet widely available for use in undergraduate laboratories. We have

  16. Frequency Response of an Air Resonance Tube--Some Computer-Interfaced Experiments.

    ERIC Educational Resources Information Center

    Jolly, Pratibha; And Others

    1993-01-01

    Describes a measurement system for recording the frequency response of acoustic systems. The computer interface detects the characteristic modes, their relative strengths, and resonant shapes over a broad range of frequencies. Includes experimental data for tubes and analyzes the data to determine the optimal functional form for the resonant…

  17. Experiment on Impulsive Excitation, Resonance, and Fourier Analysis of a Harmonic Oscillator.

    ERIC Educational Resources Information Center

    Macomber, Hilliard K.

    1981-01-01

    Describes an electric circuit permitting easy observation and measurement of the response of a damped harmonic oscillator to impulsive excitation. The impulse analysis is carried out and related to experimental observations. The phenomenon of resonance is then interpreted and demonstrated, and through it, contact is made with Fourier analysis.

  18. An Accessible Two-Dimensional Solution Nuclear Magnetic Resonance Experiment on Human Ubiquitin

    ERIC Educational Resources Information Center

    Rovnyak, David; Thompson, Laura E.

    2005-01-01

    Solution-state nuclear magnetic resonance (NMR) is an invaluable tool in structural and molecular biology research, but may be underutilized in undergraduate laboratories because instrumentation for performing structural studies of macromolecules in aqueous solutions is not yet widely available for use in undergraduate laboratories. We have…

  19. Toward Resonant, Imaginative Experiences in Ecological and Democratic Education. A Response to "Imagination and Experience: An Integrative Framework"

    ERIC Educational Resources Information Center

    Derby, Michael; Blenkinsop, Sean; Telford, John; Piersol, Laura; Caulkins, Michael

    2013-01-01

    In this response to Fettes's "Imagination and Experience," the authors further consider the varieties of educational experience that inspire ecological flourishing and a living democracy. The essential interconnectedness of encounter-driven and language-driven ways of knowing are explored with particular reference to the…

  20. 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.

  1. H(C)Ag: a triple resonance NMR experiment for (109) Ag detection in labile silver-carbene complexes.

    PubMed

    Weske, Sebastian; Li, Yingjia; Wiegmann, Sara; John, Michael

    2015-04-01

    In silver complexes, indirect detection of (109) Ag resonances via (1) H,(109) Ag-HMQC frequently suffers from small or absent JHAg couplings or rapid ligand dissociation. In these cases, it would be favourable to employ H(X)Ag triple resonance spectroscopy that uses the large one-bond JXAg coupling (where the donor atom of the ligand X is the relay nucleus). We have applied an HMQC-based version of the H(C)Ag experiment to a labile silver-NHC complex (NHC=N-heterocyclic carbene) at natural (13) C isotopic abundance and variable temperature. In agreement with simulations, H(C)Ag detection became superior to (1) H,(109) Ag-HMQC detection above -20 °C. PMID:25641122

  2. Direct electron heating experiment on the Aditya tokamak using fast waves in the ion cyclotron resonance frequency range

    NASA Astrophysics Data System (ADS)

    Mishra, Kishore; Kulkarni, S. V.; Rathi, D.; Varia, Atul D.; Jadav, H. M.; Parmar, K. M.; Kadia, B. R.; Joshi, R.; Srinivas, Y. S. S.; Singh, Raj; Kumar, Sunil; Dani, S.; Gayatri, A.; Yogi, R. A.; Manoj, Singh; Joisa, Y. S.; Rao, C. V. S.; Kumar, Sameer; Jha, R.; Manchanda, R.; Ghosh, J.; Atrey, P. K.; Bhatt, S. B.; Gupta, C. N.; Chattopadhyaya, P. K.; Chattopadhyaya, A. K.; Srinivasan, R.; Bora, Dhiraj; Kaw, P. K.; Aditya Team

    2011-09-01

    Second harmonic heating experiments using fast waves are carried out on the Aditya tokamak in the ion cyclotron resonance frequency (ICRF) range with the help of a 200 kW, 20-40 MHz RF heating system, which is developed indigenously. Significant direct electron heating is observed in a hydrogen plasma. The rise in electron temperature is prompt with the application of RF power and the increment in electron temperature increases linearly with RF power. A corresponding increase in plasma beta and hence an increase in stored diamagnetic energy are also observed in the presence of RF power. The low-Z impurity radiation and electron density do not increase significantly with RF power. The direct electron heating by fast wave in Aditya is also predicted by the ion cyclotron resonance heating code TORIC.

  3. Progress in INRiM Experiment for the Determination of the Boltzmann Constant with a Quasi-spherical Resonator

    NASA Astrophysics Data System (ADS)

    Gavioso, R. M.; Benedetto, G.; Madonna Ripa, D.; Giuliano Albo, P. A.; Guianvarc'h, C.; Merlone, A.; Pitre, L.; Truong, D.; Moro, F.; Cuccaro, R.

    2011-08-01

    Current progress in the INRiM experiment for the determination of the Boltzmann constant k B by means of acoustic thermometry is reported. Particularly, the microwave determination of the volume of a triaxial ellipsoidal resonator with an inner radius of 5 cm which was designed at LNE-CNAM is discussed. For the same cavity, acoustic measurements in helium at T w over the extended pressure range between 50 kPa and 1.4 MPa are reported and these results are compared with the predictions of a model which accounts for several perturbing effects. The procedures, methods, and results obtained in the calibration of several capsule-type SPRTs used in the experiment are briefly illustrated, together with the estimate of the temperature uniformity of the experiment.

  4. The Giant Dipole Resonance built on highly excited states — results of the MEDEA experiment

    NASA Astrophysics Data System (ADS)

    Suomijärvi, T.; Le Faou, J. H.; Blumenfeld, Y.; Piattelli, P.; Agodi, C.; Alamanos, N.; Alba, R.; Auger, F.; Bellia, G.; Chomaz, Ph.; Coniglione, R.; Del Zoppo, A.; Finocchiaro, P.; Frascaria, N.; Gaardhøje, J. J.; Garron, J. P.; Gillibert, A.; Lamehi-Rachti, M.; Liguori-Neto, R.; Maiolino, C.; Migneco, E.; Russo, G.; Roynette, J. C.; Santonocito, D.; Sapienza, P.; Scarpaci, J. A.; Smerzi, A.

    1994-03-01

    Gamma-rays, light charged particles and evaporation residues emitted from hot nuclei formed in the 36Ar + 90Zr reaction at 27 MeV/u have been measured with a nearly 4π barium fluoride multidetector. It is shown that hot Sn-like nuclei with a range of excitation energies between 300 and 600 MeV are produced. The γ-ray yield from the decay of the Giant Dipole Resonance in these nuclei is shown to remain constant over this excitation energy range. The measured γ-ray spectra are compared with statistical calculations encompassing several recent theoretical models for the quenching of gamma-ray emission from the dipole resonance at very high temperatures.

  5. Ultrasound imparted air-recoil resonance (UIAR) method for acoustic power estimation: theory and experiment.

    PubMed

    Kaiplavil, Sreekumar; Rivens, Ian; ter Haar, Gail

    2013-07-01

    Ultrasound imparted air-recoil resonance (UIAR), a new method for acoustic power estimation, is introduced with emphasis on therapeutic high-intensity focused ultrasound (HIFU) monitoring applications. Advantages of this approach over existing practices include fast response; electrical and magnetic inertness, and hence MRI compatibility; portability; high damage threshold and immunity to vibration and interference; low cost; etc. The angle of incidence should be fixed for accurate measurement. However, the transducer-detector pair can be aligned in any direction with respect to the force of gravity. In this sense, the operation of the device is orientation independent. The acoustic response of a pneumatically coupled pair of Helmholtz resonators, with one of them acting as the sensor head, is used for the estimation of acoustic power. The principle is valid in the case of pulsed/ burst as well as continuous ultrasound exposure, the former being more sensitive and accurate. An electro-acoustic theory has been developed for describing the dynamics of pressure flow and resonance in the system considering various thermo- viscous loss mechanisms. Experimental observations are found to be in agreement with theoretical results. Assuming the window damage threshold (~10 J·mm(-2)) and accuracy of RF power estimation are the upper and lower scale-limiting factors, the performance of the device was examined for an RF power range of 5 mW to 100 W with a HIFU transducer operating at 1.70 MHz, and an average nonlinearity of ~1.5% was observed. The device is also sensitive to sub-milliwatt powers. The frequency response was analyzed at 0.85, 1.70, 2.55, and 3.40 MHz and the results are presented with respective theoretical estimates. Typical response time is in the millisecond regime. Output drift is about 3% for resonant and 5% for nonresonant modes. The principle has been optimized to demonstrate a general-purpose acoustic power meter. PMID:25004503

  6. Coaxial probe for nuclear magnetic resonance diffusion and relaxation correlation experiments

    NASA Astrophysics Data System (ADS)

    Tang, Yiqiao; Hürlimann, Martin; Mandal, Soumyajit; Paulsen, Jeffrey; Song, Yi-Qiao

    2014-02-01

    A coaxial nuclear magnetic resonance (NMR) probe is built to measure diffusion and relaxation properties of liquid samples. In particular, we demonstrate the acquisition of two-dimensional (2D) distribution functions (T1-T2 and diffusion-T2), essential for fluids characterization. The compact design holds promise for miniaturization, thus enabling the measurement of molecular diffusion that is inaccessible to conventional micro-NMR setups. Potential applications range from crude oil characterization to biomolecular screening and detections.

  7. A 4 K cryogenic probe for use in magnetic resonance force microscopy experiments.

    PubMed

    Smith, Doran D; Alexson, Dimitri A; Garbini, Joseph L

    2013-09-01

    The detailed design of a mechanically detected nuclear magnetic resonance probe using the SPAM (Springiness Preservation by Aligning Magnetization) geometry, operating at 4 K, in vacuum, and a several-Tesla magnetic field is described. The probe head is vibration-isolated well enough from the environment by a three-spring suspension system that the cantilever achieves thermal equilibrium with the environment without the aid of eddy current damping. The probe uses an ultra-soft Si cantilever with a Ni sphere attached to its tip, and magnetic resonance is registered as a change in the resonant frequency of the driven cantilever. The RF system uses frequency sweeps for adiabatic rapid passage using a 500 μm diameter RF coil wound around a sapphire rod. The RF coil and optical fiber of the interferometer used to sense the cantilever's position are both located with respect to the cantilever using a Garbini micropositioner, and the sample stage is mounted on an Attocube nanopositioner. PMID:24089869

  8. A 4 K cryogenic probe for use in magnetic resonance force microscopy experiments

    NASA Astrophysics Data System (ADS)

    Smith, Doran D.; Alexson, Dimitri A.; Garbini, Joseph L.

    2013-09-01

    The detailed design of a mechanically detected nuclear magnetic resonance probe using the SPAM (Springiness Preservation by Aligning Magnetization) geometry, operating at 4 K, in vacuum, and a several-Tesla magnetic field is described. The probe head is vibration-isolated well enough from the environment by a three-spring suspension system that the cantilever achieves thermal equilibrium with the environment without the aid of eddy current damping. The probe uses an ultra-soft Si cantilever with a Ni sphere attached to its tip, and magnetic resonance is registered as a change in the resonant frequency of the driven cantilever. The RF system uses frequency sweeps for adiabatic rapid passage using a 500 μm diameter RF coil wound around a sapphire rod. The RF coil and optical fiber of the interferometer used to sense the cantilever's position are both located with respect to the cantilever using a Garbini micropositioner, and the sample stage is mounted on an Attocube nanopositioner.

  9. A 4 K cryogenic probe for use in magnetic resonance force microscopy experiments

    SciTech Connect

    Smith, Doran D.; Alexson, Dimitri A.; Garbini, Joseph L.

    2013-09-15

    The detailed design of a mechanically detected nuclear magnetic resonance probe using the SPAM (Springiness Preservation by Aligning Magnetization) geometry, operating at 4 K, in vacuum, and a several-Tesla magnetic field is described. The probe head is vibration-isolated well enough from the environment by a three-spring suspension system that the cantilever achieves thermal equilibrium with the environment without the aid of eddy current damping. The probe uses an ultra-soft Si cantilever with a Ni sphere attached to its tip, and magnetic resonance is registered as a change in the resonant frequency of the driven cantilever. The RF system uses frequency sweeps for adiabatic rapid passage using a 500 μm diameter RF coil wound around a sapphire rod. The RF coil and optical fiber of the interferometer used to sense the cantilever's position are both located with respect to the cantilever using a Garbini micropositioner, and the sample stage is mounted on an Attocube nanopositioner.

  10. A Ku band pulsed electron paramagnetic resonance spectrometer using an arbitrary waveform generator for quantum control experiments at millikelvin temperatures

    NASA Astrophysics Data System (ADS)

    Yap, Yung Szen; Tabuchi, Yutaka; Negoro, Makoto; Kagawa, Akinori; Kitagawa, Masahiro

    2015-06-01

    We present a 17 GHz (Ku band) arbitrary waveform pulsed electron paramagnetic resonance spectrometer for experiments down to millikelvin temperatures. The spectrometer is located at room temperature, while the resonator is placed either in a room temperature magnet or inside a cryogen-free dilution refrigerator; the operating temperature range of the dilution unit is from ca. 10 mK to 8 K. This combination provides the opportunity to perform quantum control experiments on electron spins in the pure-state regime. At 0.6 T, spin echo experiments were carried out using ?-irradiated quartz glass from 1 K to 12.3 mK. With decreasing temperatures, we observed an increase in spin echo signal intensities due to increasing spin polarizations, in accordance with theoretical predictions. Through experimental data fitting, thermal spin polarization at 100 mK was estimated to be at least 99%, which was almost pure state. Next, to demonstrate the ability to create arbitrary waveform pulses, we generate a shaped pulse by superposing three Gaussian pulses of different frequencies. The resulting pulse was able to selectively and coherently excite three different spin packets simultaneouslya useful ability for analyzing multi-spin system and for controlling a multi-qubit quantum computer. By applying this pulse to the inhomogeneously broadened sample, we obtain three well-resolved excitations at 8 K, 1 K, and 14 mK.

  11. 11B[27Al] and 27Al[11B] double resonance experiments on a glassy sodium aluminoborate.

    PubMed

    van Wüllen, L; Züchner, L; Müller-Warmuth, W; Eckert, H

    1996-06-01

    Cross-polarization/magic-angle spinning (CP/MAS) and rotational echo double resonance (REDOR) experiments involving two half-integer quadrupolar nuclei, 11B and 27Al, are reported, to demonstrate boron-aluminum connectivities in a model aluminoborate glass. A detailed study of the spin-lock behavior of 11B and 27Al proves to be a prerequisite for successful CP/MAS experiments. Under MAS conditions, two distinct boron sites are observed, corresponding to tetrahedral BO4/2- sites (nuclear electric quadrupole coupling constant near 0.3 MHz) and trigonal BO3/2 sites (nuclear electric quadrupole coupling constant near 2.7 MHz). The BO4/2- sites are most successfully spin-locked in the adiabatic regime at high radio frequency (RF) field strengths, whereas for the BO3/2 sites optimum spin-lock conditions are achieved in the sudden regime (low RF field strengths). These differences can be exploited for spectral editing purposes in REDOR experiments. Using corresponding T1p filters, it becomes possible to measure individual REDOR dephasing curves for both types of boron sites. The results illustrate the possible utility of heteronuclear X-Y double resonance techniques in unravelling the intermediate range order in amorphous systems containing quadrupolar nuclei. PMID:8863374

  12. A Ku band pulsed electron paramagnetic resonance spectrometer using an arbitrary waveform generator for quantum control experiments at millikelvin temperatures.

    PubMed

    Yap, Yung Szen; Tabuchi, Yutaka; Negoro, Makoto; Kagawa, Akinori; Kitagawa, Masahiro

    2015-06-01

    We present a 17 GHz (Ku band) arbitrary waveform pulsed electron paramagnetic resonance spectrometer for experiments down to millikelvin temperatures. The spectrometer is located at room temperature, while the resonator is placed either in a room temperature magnet or inside a cryogen-free dilution refrigerator; the operating temperature range of the dilution unit is from ca. 10 mK to 8 K. This combination provides the opportunity to perform quantum control experiments on electron spins in the pure-state regime. At 0.6 T, spin echo experiments were carried out using γ-irradiated quartz glass from 1 K to 12.3 mK. With decreasing temperatures, we observed an increase in spin echo signal intensities due to increasing spin polarizations, in accordance with theoretical predictions. Through experimental data fitting, thermal spin polarization at 100 mK was estimated to be at least 99%, which was almost pure state. Next, to demonstrate the ability to create arbitrary waveform pulses, we generate a shaped pulse by superposing three Gaussian pulses of different frequencies. The resulting pulse was able to selectively and coherently excite three different spin packets simultaneously-a useful ability for analyzing multi-spin system and for controlling a multi-qubit quantum computer. By applying this pulse to the inhomogeneously broadened sample, we obtain three well-resolved excitations at 8 K, 1 K, and 14 mK. PMID:26133831

  13. Polarizing holographic reflector for electron cyclotron resonant heating (ECRH) on the Tandem Mirror Experiment Upgrade (TMX-U)

    SciTech Connect

    Coffield, F.E.; Felker, B.; Gallagher, N.C. Jr.; Pedrotti, L.R.; Stallard, B.W.; Sweeney, D.W.; Wyman, E.W.; Christensen, T.E.

    1983-11-14

    A reflector for electron cyclotron resonant heating on the Tandem Mirror Experiment Upgrade has been designed to convert the high-power TE/sub 01/ output of the circular waveguide system into a linearly polarized gaussian intensity pattern in the plasma. The reflector is a computer-generated holographic optical element with a twist polarizer. Its design, fabrication, and performance are discussed. Results of the low- and high-power tests are presented. Low-power tests were used to determine the beam pattern and the degree of cross-polarization. High-power tests verified that arcing across the grooves of the twist polarizer does not occur.

  14. Ferromagnetic critical behavior in U(Co1-xFex)Al (0 ≤x ≤0.02 ) studied by 59Co nuclear quadrupole resonance measurements

    NASA Astrophysics Data System (ADS)

    Karube, K.; Hattori, T.; Ishida, K.; Kimura, N.

    2015-02-01

    In order to investigate physical properties around a ferromagnetic (FM) quantum transition point and a tricritical point (TCP) in the itinerant-electron metamagnetic compound UCoAl, we have performed the 59Co nuclear quadrupole resonance (NQR) measurement for the Fe-substituted U(Co1-xFex)Al(x =0 ,0.5 ,1 ,and2 %) in zero external magnetic field. The Fe concentration dependence of 59Co -NQR spectra at low temperatures indicates that the first-order FM transition occurs at least above x =1 % . The magnetic fluctuations along the c axis detected by the nuclear spin-spin relaxation rate 1 /T2 exhibit an anomaly at Tmax˜20 K and enhance with increasing x . These results are in good agreement with theoretical predictions and indicate the presence of prominent critical fluctuations at the TCP in this system.

  15. Coaxial probe for nuclear magnetic resonance diffusion and relaxation correlation experiments

    SciTech Connect

    Tang, Yiqiao; Hürlimann, Martin; Mandal, Soumyajit; Paulsen, Jeffrey; Song, Yi-Qiao

    2014-02-21

    A coaxial nuclear magnetic resonance (NMR) probe is built to measure diffusion and relaxation properties of liquid samples. In particular, we demonstrate the acquisition of two-dimensional (2D) distribution functions (T{sub 1}-T{sub 2} and diffusion–T{sub 2}), essential for fluids characterization. The compact design holds promise for miniaturization, thus enabling the measurement of molecular diffusion that is inaccessible to conventional micro-NMR setups. Potential applications range from crude oil characterization to biomolecular screening and detections.

  16. Nuclear magnetic resonance studies of quadrupolar nuclei and dipolar field effects

    SciTech Connect

    Urban, Jeffry Todd

    2004-12-21

    Experimental and theoretical research conducted in two areas in the field of nuclear magnetic resonance (NMR) spectroscopy is presented: (1) studies of the coherent quantum-mechanical control of the angular momentum dynamics of quadrupolar (spin I > 1/2) nuclei and its application to the determination of molecular structure; and (2) applications of the long-range nuclear dipolar field to novel NMR detection methodologies.The dissertation is organized into six chapters. The first two chapters and associated appendices are intended to be pedagogical and include an introduction to the quantum mechanical theory of pulsed NMR spectroscopy and the time dependent theory of quantum mechanics. The third chapter describes investigations of the solid-state multiple-quantum magic angle spinning (MQMAS) NMR experiment applied to I = 5/2 quadrupolar nuclei. This work reports the use of rotary resonance-matched radiofrequency irradiation for sensitivity enhancement of the I = 5/2 MQMAS experiment. These experiments exhibited certain selective line narrowing effects which were investigated theoretically.The fourth chapter extends the discussion of multiple quantum spectroscopy of quadrupolar nuclei to a mostly theoretical study of the feasibility of enhancing the resolution of nitrogen-14 NMR of large biomolecules in solution via double-quantum spectroscopy. The fifth chapter continues to extend the principles of multiple quantum NMR spectroscopy of quadrupolar nuclei to make analogies between experiments in NMR/nuclear quadrupolar resonance (NQR) and experiments in atomic/molecular optics (AMO). These analogies are made through the Hamiltonian and density operator formalism of angular momentum dynamics in the presence of electric and magnetic fields.The sixth chapter investigates the use of the macroscopic nuclear dipolar field to encode the NMR spectrum of an analyte nucleus indirectly in the magnetization of a sensor nucleus. This technique could potentially serve as an encoding module for the recently developed NMR remote detection experiment. The feasibility of using hyperpolarized xenon-129 gas as a sensor is discussed. This work also reports the use of an optical atomic magnetometer to detect the nuclear magnetization of Xe-129 gas, which has potential applicability as a detection module for NMR remote detection experiments.

  17. Multi-axis force sensing using a resonant composite piezoelectric plate: model and experiments

    NASA Astrophysics Data System (ADS)

    Castaño-Cano, Davinson; Grossard, Mathieu; Hubert, Arnaud

    2015-05-01

    Wrist force/torque sensors used in robotic applications increase the performances and flexibility of the automated tasks. They also offer new possibilities in the manufacturing process, where physical contact between the work-piece and environment is required. The wide spreading of these sensors is for now restricted by their features. As an alternative to the existing strain-gauges force sensors, this paper presents a resonant composite structure, which is sensitive to multiple components of force that are considered via the pre-stress effect. Structurally bonded piezoelectric patches are used to bring the structure to its resonance, which is shifted according to applied forces. The relationship between force and frequency shift is modelled considering the multi-physics of this smart structure. This model is built using Hamilton's principle and takes into account pre-stress phenomena. A finite element model (FEM) based on Mindlin theory for plates, has been derived from the analytical model. The FEM model is implemented in MATLAB and compared with commercial FE software. Finally, an experimental prototype validates the model, and shows that it is possible to measure multiple force-components with one single sensing element such as a plate.

  18. Search for Resonances Decaying to Top and Bottom Quarks with the CDF Experiment.

    PubMed

    Aaltonen, T; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Anzà, F; Apollinari, G; Appel, J A; Arisawa, T; Artikov, A; Asaadi, J; Ashmanskas, W; Auerbach, B; Aurisano, A; Azfar, F; Badgett, W; Bae, T; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Barria, P; Bartos, P; Bauce, M; Bedeschi, F; Behari, S; Bellettini, G; Bellinger, J; Benjamin, D; Beretvas, A; Bhatti, A; Bianchi, L; Bland, K R; Blumenfeld, B; Bocci, A; Bodek, A; Bortoletto, D; Boudreau, J; Boveia, A; Brigliadori, L; Bromberg, C; Brucken, E; Budagov, J; Budd, H S; Burkett, K; Busetto, G; Bussey, P; Butti, P; Buzatu, A; Calamba, A; Camarda, S; Campanelli, M; Canelli, F; Carls, B; Carlsmith, D; Carosi, R; Carrillo, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavaliere, V; Cerri, A; Cerrito, L; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Cho, K; Chokheli, D; Clark, A; Clarke, C; Convery, M E; Conway, J; Corbo, M; Cordelli, M; Cox, C A; Cox, D J; Cremonesi, M; Cruz, D; Cuevas, J; Culbertson, R; d'Ascenzo, N; Datta, M; de Barbaro, P; Demortier, L; Deninno, M; D'Errico, M; Devoto, F; Di Canto, A; Di Ruzza, B; Dittmann, J R; Donati, S; D'Onofrio, M; Dorigo, M; Driutti, A; Ebina, K; Edgar, R; Elagin, A; Erbacher, R; Errede, S; Esham, B; Farrington, S; Fernández Ramos, J P; Field, R; Flanagan, G; Forrest, R; Franklin, M; Freeman, J C; Frisch, H; Funakoshi, Y; Galloni, C; Garfinkel, A F; Garosi, P; Gerberich, H; Gerchtein, E; Giagu, S; Giakoumopoulou, V; Gibson, K; Ginsburg, C M; Giokaris, N; Giromini, P; Glagolev, V; Glenzinski, D; Gold, M; Goldin, D; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González López, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gramellini, E; Grosso-Pilcher, C; Group, R C; Guimaraes da Costa, J; Hahn, S R; Han, J Y; Happacher, F; Hara, K; Hare, M; Harr, R F; Harrington-Taber, T; Hatakeyama, K; Hays, C; Heinrich, J; Herndon, M; Hocker, A; Hong, Z; Hopkins, W; Hou, S; Hughes, R E; Husemann, U; Hussein, M; Huston, J; Introzzi, G; Iori, M; Ivanov, A; James, E; Jang, D; Jayatilaka, B; Jeon, E J; Jindariani, S; Jones, M; Joo, K K; Jun, S Y; Junk, T R; Kambeitz, M; Kamon, T; Karchin, P E; Kasmi, A; Kato, Y; Ketchum, W; Keung, J; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S H; Kim, S B; Kim, Y J; Kim, Y K; Kimura, N; Kirby, M; Knoepfel, K; Kondo, K; Kong, D J; Konigsberg, J; Kotwal, A V; Kreps, M; Kroll, J; Kruse, M; Kuhr, T; Kurata, M; Laasanen, A T; Lammel, S; Lancaster, M; Lannon, K; Latino, G; Lee, H S; Lee, J S; Leo, S; Leone, S; Lewis, J D; Limosani, A; Lipeles, E; Lister, A; Liu, H; Liu, Q; Liu, T; Lockwitz, S; Loginov, A; Lucchesi, D; Lucà, A; Lueck, J; Lujan, P; Lukens, P; Lungu, G; Lys, J; Lysak, R; Madrak, R; Maestro, P; Malik, S; Manca, G; Manousakis-Katsikakis, A; Marchese, L; Margaroli, F; Marino, P; Matera, K; Mattson, M E; Mazzacane, A; Mazzanti, P; McNulty, R; Mehta, A; Mehtala, P; Mesropian, C; Miao, T; Mietlicki, D; Mitra, A; Miyake, H; Moed, S; Moggi, N; Moon, C S; Moore, R; Morello, M J; Mukherjee, A; Muller, Th; Murat, P; Mussini, M; Nachtman, J; Nagai, Y; Naganoma, J; Nakano, I; Napier, A; Nett, J; Neu, C; Nigmanov, T; Nodulman, L; Noh, S Y; Norniella, O; Oakes, L; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Orava, R; Ortolan, L; Pagliarone, C; Palencia, E; Palni, P; Papadimitriou, V; Parker, W; Pauletta, G; Paulini, M; Paus, C; Phillips, T J; Piacentino, G; Pianori, E; Pilot, J; Pitts, K; Plager, C; Pondrom, L; Poprocki, S; Potamianos, K; Pranko, A; Prokoshin, F; Ptohos, F; Punzi, G; Redondo Fernández, I; Renton, P; Rescigno, M; Rimondi, F; Ristori, L; Robson, A; Rodriguez, T; Rolli, S; Ronzani, M; Roser, R; Rosner, J L; Ruffini, F; Ruiz, A; Russ, J; Rusu, V; Sakumoto, W K; Sakurai, Y; Santi, L; Sato, K; Saveliev, V; Savoy-Navarro, A; Schlabach, P; Schmidt, E E; Schwarz, T; Scodellaro, L; Scuri, F; Seidel, S; Seiya, Y; Semenov, A; Sforza, F; Shalhout, S Z; Shears, T; Shepard, P F; Shimojima, M; Shochet, M; Shreyber-Tecker, I; Simonenko, A; Sliwa, K; Smith, J R; Snider, F D; Song, H; Sorin, V; St Denis, R; Stancari, M; Stentz, D; Strologas, J; Sudo, Y; Sukhanov, A; Suslov, I; Takemasa, K; Takeuchi, Y; Tang, J; Tecchio, M; Teng, P K; Thom, J; Thomson, E; Thukral, V; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Totaro, P; Trovato, M; Ukegawa, F; Uozumi, S; Vázquez, F; Velev, G; Vellidis, C; Vernieri, C; Vidal, M; Vilar, R; Vizán, J; Vogel, M; Volpi, G; Wagner, P; Wallny, R; Wang, S M; Waters, D; Wester, W C; Whiteson, D; Wicklund, A B; Wilbur, S; Williams, H H; Wilson, J S; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, H; Wright, T; Wu, X; Wu, Z; Yamamoto, K; Yamato, D; Yang, T; Yang, U K; Yang, Y C; Yao, W-M; Yeh, G P; Yi, K; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Zanetti, A M; Zeng, Y; Zhou, C; Zucchelli, S

    2015-08-01

    We report on a search for charged massive resonances decaying to top (t) and bottom (b) quarks in the full data set of proton-antiproton collisions at a center-of-mass energy of √[s]=1.96  TeV collected by the CDF II detector at the Tevatron, corresponding to an integrated luminosity of 9.5  fb(-1). No significant excess above the standard model background prediction is observed. We set 95% Bayesian credibility mass-dependent upper limits on the heavy charged-particle production cross section times branching ratio to tb. Using a standard model extension with a W'→tb and left-right-symmetric couplings as a benchmark model, we constrain the W' mass and couplings in the 300-900  GeV/c(2) range. The limits presented here are the most stringent for a charged resonance with mass in the range 300-600  GeV/c(2) decaying to top and bottom quarks. PMID:26296108

  19. Search for Resonances Decaying to Top and Bottom Quarks with the CDF Experiment

    NASA Astrophysics Data System (ADS)

    Aaltonen, T.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Anzà, F.; Apollinari, G.; Appel, J. A.; Arisawa, T.; Artikov, A.; Asaadi, J.; Ashmanskas, W.; Auerbach, B.; Aurisano, A.; Azfar, F.; Badgett, W.; Bae, T.; Barbaro-Galtieri, A.; Barnes, V. E.; Barnett, B. A.; Barria, P.; Bartos, P.; Bauce, M.; Bedeschi, F.; Behari, S.; Bellettini, G.; Bellinger, J.; Benjamin, D.; Beretvas, A.; Bhatti, A.; Bianchi, L.; Bland, K. R.; Blumenfeld, B.; Bocci, A.; Bodek, A.; Bortoletto, D.; Boudreau, J.; Boveia, A.; Brigliadori, L.; Bromberg, C.; Brucken, E.; Budagov, J.; Budd, H. S.; Burkett, K.; Busetto, G.; Bussey, P.; Butti, P.; Buzatu, A.; Calamba, A.; Camarda, S.; Campanelli, M.; Canelli, F.; Carls, B.; Carlsmith, D.; Carosi, R.; Carrillo, S.; Casal, B.; Casarsa, M.; Castro, A.; Catastini, P.; Cauz, D.; Cavaliere, V.; Cerri, A.; Cerrito, L.; Chen, Y. C.; Chertok, M.; Chiarelli, G.; Chlachidze, G.; Cho, K.; Chokheli, D.; Clark, A.; Clarke, C.; Convery, M. E.; Conway, J.; Corbo, M.; Cordelli, M.; Cox, C. A.; Cox, D. J.; Cremonesi, M.; Cruz, D.; Cuevas, J.; Culbertson, R.; d'Ascenzo, N.; Datta, M.; de Barbaro, P.; Demortier, L.; Deninno, M.; D'Errico, M.; Devoto, F.; Di Canto, A.; Di Ruzza, B.; Dittmann, J. R.; Donati, S.; D'Onofrio, M.; Dorigo, M.; Driutti, A.; Ebina, K.; Edgar, R.; Elagin, A.; Erbacher, R.; Errede, S.; Esham, B.; Farrington, S.; Fernández Ramos, J. P.; Field, R.; Flanagan, G.; Forrest, R.; Franklin, M.; Freeman, J. C.; Frisch, H.; Funakoshi, Y.; Galloni, C.; Garfinkel, A. F.; Garosi, P.; Gerberich, H.; Gerchtein, E.; Giagu, S.; Giakoumopoulou, V.; Gibson, K.; Ginsburg, C. M.; Giokaris, N.; Giromini, P.; Glagolev, V.; Glenzinski, D.; Gold, M.; Goldin, D.; Golossanov, A.; Gomez, G.; Gomez-Ceballos, G.; Goncharov, M.; González López, O.; Gorelov, I.; Goshaw, A. T.; Goulianos, K.; Gramellini, E.; Grosso-Pilcher, C.; Group, R. C.; Guimaraes da Costa, J.; Hahn, S. R.; Han, J. Y.; Happacher, F.; Hara, K.; Hare, M.; Harr, R. F.; Harrington-Taber, T.; Hatakeyama, K.; Hays, C.; Heinrich, J.; Herndon, M.; Hocker, A.; Hong, Z.; Hopkins, W.; Hou, S.; Hughes, R. E.; Husemann, U.; Hussein, M.; Huston, J.; Introzzi, G.; Iori, M.; Ivanov, A.; James, E.; Jang, D.; Jayatilaka, B.; Jeon, E. J.; Jindariani, S.; Jones, M.; Joo, K. K.; Jun, S. Y.; Junk, T. R.; Kambeitz, M.; Kamon, T.; Karchin, P. E.; Kasmi, A.; Kato, Y.; Ketchum, W.; Keung, J.; Kilminster, B.; Kim, D. H.; Kim, H. S.; Kim, J. E.; Kim, M. J.; Kim, S. H.; Kim, S. B.; Kim, Y. J.; Kim, Y. K.; Kimura, N.; Kirby, M.; Knoepfel, K.; Kondo, K.; Kong, D. J.; Konigsberg, J.; Kotwal, A. V.; Kreps, M.; Kroll, J.; Kruse, M.; Kuhr, T.; Kurata, M.; Laasanen, A. T.; Lammel, S.; Lancaster, M.; Lannon, K.; Latino, G.; Lee, H. S.; Lee, J. S.; Leo, S.; Leone, S.; Lewis, J. D.; Limosani, A.; Lipeles, E.; Lister, A.; Liu, H.; Liu, Q.; Liu, T.; Lockwitz, S.; Loginov, A.; Lucchesi, D.; Lucà, A.; Lueck, J.; Lujan, P.; Lukens, P.; Lungu, G.; Lys, J.; Lysak, R.; Madrak, R.; Maestro, P.; Malik, S.; Manca, G.; Manousakis-Katsikakis, A.; Marchese, L.; Margaroli, F.; Marino, P.; Matera, K.; Mattson, M. E.; Mazzacane, A.; Mazzanti, P.; McNulty, R.; Mehta, A.; Mehtala, P.; Mesropian, C.; Miao, T.; Mietlicki, D.; Mitra, A.; Miyake, H.; Moed, S.; Moggi, N.; Moon, C. S.; Moore, R.; Morello, M. J.; Mukherjee, A.; Muller, Th.; Murat, P.; Mussini, M.; Nachtman, J.; Nagai, Y.; Naganoma, J.; Nakano, I.; Napier, A.; Nett, J.; Neu, C.; Nigmanov, T.; Nodulman, L.; Noh, S. Y.; Norniella, O.; Oakes, L.; Oh, S. H.; Oh, Y. D.; Oksuzian, I.; Okusawa, T.; Orava, R.; Ortolan, L.; Pagliarone, C.; Palencia, E.; Palni, P.; Papadimitriou, V.; Parker, W.; Pauletta, G.; Paulini, M.; Paus, C.; Phillips, T. J.; Piacentino, G.; Pianori, E.; Pilot, J.; Pitts, K.; Plager, C.; Pondrom, L.; Poprocki, S.; Potamianos, K.; Pranko, A.; Prokoshin, F.; Ptohos, F.; Punzi, G.; Redondo Fernández, I.; Renton, P.; Rescigno, M.; Rimondi, F.; Ristori, L.; Robson, A.; Rodriguez, T.; Rolli, S.; Ronzani, M.; Roser, R.; Rosner, J. L.; Ruffini, F.; Ruiz, A.; Russ, J.; Rusu, V.; Sakumoto, W. K.; Sakurai, Y.; Santi, L.; Sato, K.; Saveliev, V.; Savoy-Navarro, A.; Schlabach, P.; Schmidt, E. E.; Schwarz, T.; Scodellaro, L.; Scuri, F.; Seidel, S.; Seiya, Y.; Semenov, A.; Sforza, F.; Shalhout, S. Z.; Shears, T.; Shepard, P. F.; Shimojima, M.; Shochet, M.; Shreyber-Tecker, I.; Simonenko, A.; Sliwa, K.; Smith, J. R.; Snider, F. D.; Song, H.; Sorin, V.; St. Denis, R.; Stancari, M.; Stentz, D.; Strologas, J.; Sudo, Y.; Sukhanov, A.; Suslov, I.; Takemasa, K.; Takeuchi, Y.; Tang, J.; Tecchio, M.; Teng, P. K.; Thom, J.; Thomson, E.; Thukral, V.; Toback, D.; Tokar, S.; Tollefson, K.; Tomura, T.; Tonelli, D.; Torre, S.; Torretta, D.; Totaro, P.; Trovato, M.; Ukegawa, F.; Uozumi, S.; Vázquez, F.; Velev, G.; Vellidis, C.; Vernieri, C.; Vidal, M.; Vilar, R.; Vizán, J.; Vogel, M.; Volpi, G.; Wagner, P.; Wallny, R.; Wang, S. M.; Waters, D.; Wester, W. C.; Whiteson, D.; Wicklund, A. B.; Wilbur, S.; Williams, H. H.; Wilson, J. S.; Wilson, P.; Winer, B. L.; Wittich, P.; Wolbers, S.; Wolfe, H.; Wright, T.; Wu, X.; Wu, Z.; Yamamoto, K.; Yamato, D.; Yang, T.; Yang, U. K.; Yang, Y. C.; Yao, W.-M.; Yeh, G. P.; Yi, K.; Yoh, J.; Yorita, K.; Yoshida, T.; Yu, G. B.; Yu, I.; Zanetti, A. M.; Zeng, Y.; Zhou, C.; Zucchelli, S.; CDF Collaboration

    2015-08-01

    We report on a search for charged massive resonances decaying to top (t ) and bottom (b ) quarks in the full data set of proton-antiproton collisions at a center-of-mass energy of √{s }=1.96 TeV collected by the CDF II detector at the Tevatron, corresponding to an integrated luminosity of 9.5 fb-1 . No significant excess above the standard model background prediction is observed. We set 95% Bayesian credibility mass-dependent upper limits on the heavy charged-particle production cross section times branching ratio to t b . Using a standard model extension with a W'→t b and left-right-symmetric couplings as a benchmark model, we constrain the W' mass and couplings in the 300 - 900 GeV /c2 range. The limits presented here are the most stringent for a charged resonance with mass in the range 300 - 600 GeV /c2 decaying to top and bottom quarks.

  20. Search for resonances decaying to top and bottom quarks with the CDF experiment

    SciTech Connect

    Aaltonen, Timo Antero

    2015-08-03

    We report on a search for charged massive resonances decaying to top (t) and bottom (b) quarks in the full data set of proton-antiproton collisions at a center-of-mass energy of √s = 1.96 TeV collected by the CDF II detector at the Tevatron, corresponding to an integrated luminosity of 9.5 fb–1. No significant excess above the standard model background prediction is observed. We set 95% Bayesian credibility mass-dependent upper limits on the heavy charged-particle production cross section times branching ratio to tb. Using a standard model extension with a W' → tb and left-right-symmetric couplings as a benchmark model, we constrain the W' mass and couplings in the 300–900 GeV/c2 range. As a result, the limits presented here are the most stringent for a charged resonance with mass in the range 300–600 GeV/c2 decaying to top and bottom quarks.

  1. A p-spin high-pass filter using radiofrequency field gradients for homonuclear magnetic resonance experiments

    NASA Astrophysics Data System (ADS)

    Canet, Daniel; Mutzenhardt, Pierre; Brondeau, Jean

    Traditional multiple-quantum filtering in nuclear magnetic resonance spectroscopy relies on the acquisition of several transients along with appropriate phase cycling. It is shown that similar results can be obtained in one transient by using a cluster of two radiofrequency field (B1) gradient pulses (g1)x(rg1)y where g1 and rg1 denote the durations of the B1 gradient pulses and the subscripts x and y the transmitter phases. This filter acts on single-quantum antiphase coherences and is of high-pass nature. The choice of r determines the order of the filter (according to the number of spins belonging to the system considered). This property is demonstrated theoretically and verified experimentally by dedicated one-dimensional experiments and COSY-type two-dimensional experiments.

  2. Neutron emission spectroscopy results for internal transport barrier and mode conversion ion cyclotron resonance heating experiments at JETa)

    NASA Astrophysics Data System (ADS)

    Giacomelli, L.; Hjalmarsson, A.; Källne, J.; Hellesen, C.; Tardocchi, M.; Gorini, G.; Eester, D. Van; Lerche, E.; Johnson, T.; Kiptily, V.; Conroy, S.; Sundén, E. Andersson; Ericsson, G.; Johnson, M. Gatu; Sjöstrand, H.; Weiszflog, M.; Jet-Efda Contributors

    2008-10-01

    The effect of ion cyclotron resonance heating (ICRH) on (H3e)D plasmas at JET was studied with the time of flight optimized rate (TOFOR) spectrometer dedicated to 2.5 MeV dd neutron measurements. In internal transport barrier (ITB) plasma experiments with large H3e concentrations (X(H3e)>15%) an increase in neutron yield was observed after the ITB disappeared but with the auxiliary neutral beam injection and ICRH power still applied. The analysis of the TOFOR data revealed the formation of a high energy (fast) D population in this regime. The results were compared to other mode conversion experiments with similar X(H3e) but slightly different heating conditions. In this study we report on the high energy neutron tails originating from the fast D ions and their correlation with X(H3e) and discuss the light it can shed on ICRH-plasma power coupling mechanisms.

  3. Using an NMR Spectrometer to Do Magnetic Resonance Imaging: An Undergraduate Physical Chemistry Laboratory Experiment

    ERIC Educational Resources Information Center

    Steinmetz, Wayne E.; Maher, M. Cyrus

    2007-01-01

    A conventional Fourier-transform NMR spectrometer with a triple-axis gradient probe can function as a MRI imager. In this experiment students gain hands-on experience with MRI while they learn about important principles underlying the practice of NMR, such as gradients, multi-dimensional spectroscopy, and relaxation. Students image a biological…

  4. Switching from visibility to invisibility via Fano resonances: theory and experiment.

    PubMed

    Rybin, Mikhail V; Filonov, Dmitry S; Belov, Pavel A; Kivshar, Yuri S; Limonov, Mikhail F

    2015-01-01

    Subwavelength structures demonstrate many unusual optical properties which can be employed for engineering of a new generation of functional metadevices, as well as controlled scattering of light and invisibility cloaking. Here we demonstrate that the suppression of light scattering for any direction of observation can be achieved for a uniform dielectric object with high refractive index, in a sharp contrast to the cloaking with multilayered plasmonic structures suggested previously. Our finding is based on the novel physics of cascades of Fano resonances observed in the Mie scattering from a homogeneous dielectric rod. We observe this effect experimentally at microwaves by employing high temperature-dependent dielectric permittivity of a glass cylinder with heated water. Our results open a new avenue in analyzing the optical response of high-index dielectric nanoparticles and the physics of cloaking. PMID:25739324

  5. Switching from Visibility to Invisibility via Fano Resonances: Theory and Experiment

    NASA Astrophysics Data System (ADS)

    Rybin, Mikhail V.; Filonov, Dmitry S.; Belov, Pavel A.; Kivshar, Yuri S.; Limonov, Mikhail F.

    2015-03-01

    Subwavelength structures demonstrate many unusual optical properties which can be employed for engineering of a new generation of functional metadevices, as well as controlled scattering of light and invisibility cloaking. Here we demonstrate that the suppression of light scattering for any direction of observation can be achieved for a uniform dielectric object with high refractive index, in a sharp contrast to the cloaking with multilayered plasmonic structures suggested previously. Our finding is based on the novel physics of cascades of Fano resonances observed in the Mie scattering from a homogeneous dielectric rod. We observe this effect experimentally at microwaves by employing high temperature-dependent dielectric permittivity of a glass cylinder with heated water. Our results open a new avenue in analyzing the optical response of high-index dielectric nanoparticles and the physics of cloaking.

  6. Switching from Visibility to Invisibility via Fano Resonances: Theory and Experiment

    PubMed Central

    Rybin, Mikhail V.; Filonov, Dmitry S.; Belov, Pavel A.; Kivshar, Yuri S.; Limonov, Mikhail F.

    2015-01-01

    Subwavelength structures demonstrate many unusual optical properties which can be employed for engineering of a new generation of functional metadevices, as well as controlled scattering of light and invisibility cloaking. Here we demonstrate that the suppression of light scattering for any direction of observation can be achieved for a uniform dielectric object with high refractive index, in a sharp contrast to the cloaking with multilayered plasmonic structures suggested previously. Our finding is based on the novel physics of cascades of Fano resonances observed in the Mie scattering from a homogeneous dielectric rod. We observe this effect experimentally at microwaves by employing high temperature-dependent dielectric permittivity of a glass cylinder with heated water. Our results open a new avenue in analyzing the optical response of high-index dielectric nanoparticles and the physics of cloaking. PMID:25739324

  7. On the second harmonic electron cyclotron resonance heating and current drive experiments on T-10 and DIII-D

    SciTech Connect

    Lohr, J.; Forest, C.B.; Lin-Liu, Y.R.; Luce, T.C.; Harvey, R.W.; Downs, E.A. |; James, R.A. |; Bagdasarov, A.A.; Borshegovskii, A.A.; Chistyakov, V.V.; Dremin, M.M.; Gorshkov, A.V.; Gorelov, Y.A.; Esipchuk, Y.V.; Ivanov, N.V.; Kislov, A.Y.; Kislov, D.A.; Lysenko, S.E.; Medvedev, A.A.; Mirenskii, V.Y.; Notkin, G.E.; Parail, V.V.; Pavlov, Y.D.; Razumova, K.A.; Roi, I.N.; Savrukhin, P.V.; Sannikov, V.V.; Sushkov, A.V.; Trukhin, V.M.; Vasin, N.L.; Volkov, V.V.; Denisov, G.G.; Petelin, M.I.; Flyagin, V.A.

    1993-02-01

    Studies of electron cyclotron current drive at the second harmonic resonance have been performed both on the DIII-D and T-10 tokamaks at injected power levels of approximately 0.5 MW. The DIII-D experiment used high held launch of the extraordinary mode at an angle of 15{degree} to the radial. In this experiment, with pulse lengths {approx_equal} 500 msec, a loop voltage difference, compared to the value expected from the measured profiles, of {approx_equal} 50 mV was ascribed to approximately 50 kA of rf-driven current. When dc electric field and trapped particle effects were considered, this was consistent with theoretical predictions. T-10 experiments planned for the fall of 1992 will use low field launch of the extraordinary mode and an injection angle of 21{degree} off-radial. In preliminary experiments with relatively poor machine conditions and pulse lengths {approx_equal} 400 msec, rf current drive was not observed despite the fact that driven currents as low as 10 kA, corresponding to a loop voltage difference for co- versus counter-injection of 20 mV, could have been detected. In this paper we examine the T-10 experiments using ray tracing and transport calculations in an attempt to understand the results. The dependence of the current drive efficiency on discharge parameters, flux penetration, and non-linear effects will be discussed. The results show that the launching geometry can have a significant effect on the observation of electron cyclotron current drive using the loop voltage as a diagnostic. In addition, predictions for the next series of experiments on T-10, for which greater than 2 MW of high frequency power should be available, will be presented.

  8. Nongated cardiac magnetic resonance imaging: preliminary experience at 0. 12 T

    SciTech Connect

    Choyke, P.L.; Kressel, H.Y.; Reichek, N.; Axel, L.; Gefter, W.; Mamourian, A.C.; Thickman, D.

    1984-12-01

    Nongated cardiac magnetic resonance imaging (MRI) has been reported previously to be inadequate for obtaining diagnostic information. This study explored the role of pulse sequence in the degradation of the nongated cardiac image. Images of diagnostic quality were obtained by using single spin-echo sequences with a very short echo time (10-20 msec TE) on a 0.12-T development MR unit. Marked degradation of the image was noted with longer TEs. Short-TE technique was used to examine 34 patients with a variety of cardiac diseases. Eleven patients had ventricular aneurysms. Twenty patients had left ventricular hypertrophy that was concentric in 11. Six patients had extrinsic masses displacing the heart and distorting the chamber contour. One patient with ventricular septal defect (VSD) and corrected transposition was scanned. In addition to identifying the VSD and chamber hypertrophy, the malposition of the great vessels at the base of the heart was seen. Four postoperative patients were scanned; wire suture artifact did not preclude imaging. In conclusion, diagnostic information can be obtained from nongated cardiac images provided that the TE is very short (10-20 msec). Although quantitative functional data are not available from nongated images, qualitative and diagnostic information is possible and may suffice in certain circumstances.

  9. Magnetic Resonance-Guided Percutaneous Cryoablation of Uterine Fibroids: Early Clinical Experiences

    SciTech Connect

    Sakuhara, Yusuke Shimizu, Tadashi; Kodama, Yoshihisa; Sawada, Akihiro; Endo, Hideho; Abo, Daisuke; Hasegawa, Tenshu; Miyasaka, Kazuo

    2006-08-15

    Purpose. Uterine fibroids (leiomyomas) are the most common tumors of the uterus. The present study evaluated the feasibility and effectiveness of magnetic resonance (MR)-guided percutaneous cryoablation for uterine fibroids as a minimally invasive treatment alternative. Methods. From August 2001 to June 2002, MR-guided percutaneous cryoablation was performed on seven uterine fibroids in 6 patients who displayed clinical symptoms related to tumors. Using a horizontal-type open MR system, cryoablation probes were percutaneously placed in fibroids. Fibroids were ablated, and the site and size of ice balls were monitored on MR imaging. Postoperatively, patients completed a questionnaire to assess changes in presenting clinical symptoms, and MR images were obtained for all patients at follow-up. Changes in clinical symptoms and tumor volume were evaluated in each patient. Results. All treated patients showed reductions in tumor size. Mean volume reduction rate was 40.3% at 6 weeks postoperatively, and 79.4% at 9-12 months. All patients reported fever after treatment. Surgical drainage was required for abscess in the probe channel in one patient, and transient liver damage occurred in another. Subjective symptoms improved in all patients except one who had multiple tumors, and no patient complained of new symptoms after cryoablation during follow-up. Conclusion. MR-guided percutaneous cryoablation represents a feasible and effective treatment for uterine fibroids.

  10. The Fetal Magnetic Resonance Imaging Experience in a Large Community Medical Center

    PubMed Central

    Ghobrial, Peter M; Levy, Rebecca A; O’Connor, Stephen C

    2011-01-01

    Fetal magnetic resonance imaging (MRI) continues to prove a useful problem solving tool for diagnostic and management decision making issues encountered in the antenatal period. In this paper, we attempt to review basic fetal MRI protocol considerations and demonstrate key imaging findings through multiple modalities, with pathologic correlation in several cases. A study of five fetal MRI cases, from our institution, were selected in order to highlight both the indications for, and benefits obtained from this advanced imaging technique. Fetal MRI proved useful in each case in better defining fetal anomalies, especially where ultrasound (due to drawbacks such as shadowing by pelvic bones) was unable to be completely diagnostic. The more in-depth study made possible by MRI also helped with formulation of disease prognosis and estimation of survival chances of the fetus. Further, MRI as a diagnostic and prognostic tool has become more ubiquitous across the medical community. This imparts tangible benefit to patients, who are now able to find this service within arm's reach. Whereas previously these patients were obligatorily referred up to 90 miles away from our centre for further medical work-up, now a large percentage can obtain their prenatal imaging and perinatal care locally. In addition, medical education benefits as new types of cases, those with pathology of the antenatal period, are retained for work-up and management in these large community settings. Cases from our institution exemplify these types of pathologies, from fetal chest masses to a syndromic presentation of bilateral renal agenesis. PMID:21966626

  11. In Utero Detection of Retinoblastoma with Fetal Magnetic Resonance and Ultrasound: Initial Experience

    PubMed Central

    Paquette, Lisa B.; Miller, David; Jackson, Hollie A.; Lee, Thomas; Randolph, Linda; Murphree, A. Lynn; Panigrahy, Ashok

    2012-01-01

    Purpose Our aim was to evaluate and compare the ability of prenatal ultrasound (US) and fetal magnetic resonance imaging (MRI) to detect retinoblastoma lesions in utero. Methods Fetuses at risk for having bilateral retinoblastoma were enrolled in this prospective study. High-resolution US of the fetal eye was performed at 16 to 18 weeks' gestation, every 4 weeks until 32 weeks, then every 2 weeks until delivery. Fetal MRIs were performed every 8 weeks starting at 16 to 18 weeks of gestation. An exam under anesthesia (EUA) was performed postnatally, the gold standard of this study. Lesions were classified as being elevated or minimally elevated based upon their morphology. Results Of six fetuses suspected or confirmed to be at risk for developing bilateral retinoblastoma, one had tumors on her first postnatal EUA exam. A total of two minimally elevated lesions were seen by the EUA but not detected prenatally by imaging. One elevated lesion (2 mm in height) identified by postnatal EUA was initially identified by prenatal US. Fetal MRI did not detect any lesions. Conclusion Both prenatal US and fetal MRI are limited in the detection of minimally elevated retinoblastoma lesions. Prenatal US appears to be more sensitive than fetal MRI in the detection of elevated retinoblastoma lesions. PMID:23946908

  12. Development of Low Temperature Nuclear Magnetic Resonance Force Microscopy (NMRFM) Experiments for Probing Nanoscale Films and Microcrystals

    NASA Astrophysics Data System (ADS)

    Paster, Jeremy; Tennant, Daniel; Mozaffari, Shirin; Markert, John

    2014-03-01

    Force detection of nuclear spins is accomplished by coupling NMR spin-flip sequences to a mechanical oscillator. A thin ferromagnet deposited on the tip of the oscillator sets up a large gradient magnetic field in the vicinity of the spins. This provides a magnetic force signature which we can distinguish from the thermal noise of the oscillator. The gradient field also traces out a slice in space in which spins are resonantly tuned to the RF field. We review the advantages of various strategies for inducing nuclear spin flips including cantilever-driven and RF-modulation techniques. We also report on the current state of the project, highlighting important developments and experimental results. In particular, we've adapted a low temperature NMRFM probe for easy transition between thin-film and microcrystal experiments. In one configuration, we orient the oscillator perpendicular to the sample plane so we can work in the region where the ferromagnet's field gradient is largest. Conversely, we can rotate the oscillator 90 degrees to change the geometry of the gradient field. With this orientation we maximize resolution in one dimension by using the flat part of the resonance slice to pick up as many in-plane nuclei as we can.

  13. Focusing twist reflector for electron-cyclotron resonance heating in the Tandem Mirror Experiment-Upgrade

    SciTech Connect

    Stallard, B.W.; Coffield, F.E.; Felker, B.; Taska, J.; Christensen, T.E.; Gallagher, N.C. Jr.; Sweeney, D.W.

    1984-05-01

    A twist reflector plate is described that linearly polarizes and focuses the TE/sub O/sub 1// circular waveguide mode for heating hot electrons in the thermal barrier of the Tandem Mirror Experiment-Upgrade (TMX-U). The plate polarizing efficiency is 95%, and it has operated satisfactorily at 150 kW power level.

  14. Geomagnetic field-line resonant harmonics measured by the Viking and AMPTE/CCE magnetic field experiments

    NASA Technical Reports Server (NTRS)

    Zanetti, L. J.; Potemra, T. A.; Erlandson, R. E.; Engebretson, M. J.; Acuna, M. H.

    1987-01-01

    The first simultaneous observations of multiple harmonic, azimuthally polarized, ULF pulsations at two points along a geomagnetic flux tube in space are reported. In March 1986, the elliptically orbiting equatorial AMPTE/CCE satellite was oriented with the apogee near 0830 h MLT, and the orbital plane of the polar-orbiting Viking satellite was at 1000 MLT. The satellites were situated within approximately the same flux tube but with an effective separation of approximately 10 R(e) near L = 8 on the inbound pass of the AMPTE/CCE orbit. Structured harmonic pulsations were observed by the magnetic field experiments on both spacecraft, and they appeared to turn off and on simultaneously at both locations. Both the observations and the relative amplitudes along the magnetic field lines support recent ideas of multiple field-line resonances of Alfven waves.

  15. A new sample environment for cryogenic nuclear resonance scattering experiments on single crystals and microsamples at P01, PETRA III

    NASA Astrophysics Data System (ADS)

    Rackwitz, Sergej; Faus, Isabelle; Schmitz, Markus; Kelm, Harald; Krüger, Hans-Jörg; Andersson, K. Kristoffer; Hersleth, Hans-Petter; Achterhold, Klaus; Schlage, Kai; Wille, Hans-Christian; Schünemann, Volker; Wolny, Juliusz A.

    2014-04-01

    In order to carry out orientation dependent nuclear resonance scattering (NRS) experiments on small single crystals of e.g. iron proteins and/or chemical complexes but also on surfaces and other micrometer-sized samples a 2-circle goniometer including sample positioning optics has been installed at beamline P01, PETRA III, DESY, Hamburg. This sample environment is now available for all users of this beamline. Sample cooling is performed with a cryogenic gas stream which allows NRS measurements in the temperature range from 80 up to 400 K. In a first test this new sample environment has been used in order to investigate the orientation dependence of the nuclear inelastic scattering (NIS) signature of (i) a dinuclear iron(II) spin crossover (SCO) system and (ii) a hydrogen peroxide treated metmyoglobin single crystal.

  16. Construction of a 100kW Electron Cyclotron Resonant Heating (ECRH) system on the Madison Plasma Dynamo Experiment (MPDX)

    NASA Astrophysics Data System (ADS)

    Clark, M. M.; Milhone, J.; Nonn, P.; Wallace, J. P.; Forest, C. B.; WiPAL Team

    2015-11-01

    A system of five 20 kW magnetrons is being installed for the Madison Plasma Dynamo Experiment (MPDX) to produce and heat the plasma with RF energy. Each magnetron will receive 2.5A of 14kV DC power. The source of the DC power is from a 240V three phase line which is transformed to high voltage, rectified, and processed through a series modulator regulator circuit. The RF is transmitted to the vessel via WR284 waveguide. The actions taken to develop the DC power source will be discussed and illustrated. The vessel of MPDX is a 3 meter diameter sphere comprised of two nearly identical hemispherical shells of 1.25'' thick cast aluminum. 36 Rings of SmCo magnets attached to the inner vessel surface create a cusp field to contain the plasma and provide a resonance surface for the RF.

  17. Pulsed Fourier-transform NQR of sup 14 N with a dc SQUID

    SciTech Connect

    Huerlimann, M.D.; Pennington, C.H.; Fan, N.Q.; Clarke, J.; Pines, A.; Hahn, E.L. Department of Chemistry, University of California, Berkeley, Berkeley, California 94720 Materials Sciences Division, Lawrence Berkeley Laboratory, Berkeley, California 94720 )

    1992-07-27

    The zero-field free induction decay of solid ammonium perchlorate at 1.5 K has been directly detected with a dc superconducting quantum interference device. The Fourier-transform spectrum consists of three sharp lines at 17.4, 38.8, and 56.2 kHz arising from pure {sup 14}N nuclear quadrupole resonance transitions. The absence of splittings and resonance transitions from dipolar-coupled proton spins is attributed to reorientation of the ammonium groups by quantum tunneling in combination with motional averaging in the three proton levels characterized by the irreducible representation {ital T}. The measured {sup 14}N spin-spin relaxation time is 22{plus minus}2 ms and the spin-lattice relaxation time is 63{plus minus}6 ms.

  18. 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.

  19. On the use of Cramr-Rao minimum variance bounds for the design of magnetic resonance spectroscopy experiments.

    PubMed

    Bolliger, Christine S; Boesch, Chris; Kreis, Roland

    2013-12-01

    Localized Magnetic Resonance Spectroscopy (MRS) is in widespread use for clinical brain research. Standard acquisition sequences to obtain one-dimensional spectra suffer from substantial overlap of spectral contributions from many metabolites. Therefore, specially tuned editing sequences or two-dimensional acquisition schemes are applied to extend the information content. Tuning specific acquisition parameters allows to make the sequences more efficient or more specific for certain target metabolites. Cramr-Rao bounds have been used in other fields for optimization of experiments and are now shown to be very useful as design criteria for localized MRS sequence optimization. The principle is illustrated for one- and two-dimensional MRS, in particular the 2D separation experiment, where the usual restriction to equidistant echo time spacings and equal acquisition times per echo time can be abolished. Particular emphasis is placed on optimizing experiments for quantification of GABA and glutamate. The basic principles are verified by Monte Carlo simulations and in vivo for repeated acquisitions of generalized two-dimensional separation brain spectra obtained from healthy subjects and expanded by bootstrapping for better definition of the quantification uncertainties. PMID:23933043

  20. High-resolution solid-state nuclear magnetic resonance experiments on highly radioactive ceramics

    NASA Astrophysics Data System (ADS)

    Farnan, Ian; Cho, Herman; Weber, William J.; Scheele, Randall D.; Johnson, Nigel R.; Kozelisky, Anne E.

    2004-12-01

    A triple-containment magic-angle spinning rotor insert system has been developed and a sample handling procedure formulated for safely analyzing highly radioactive solids by high-resolution solid-state NMR. The protocol and containment system have been demonstrated for magic-angle spinning (MAS) experiments on ceramic samples containing 5-10 wt % 239Pu and 238Pu at rotation speeds of 3500 Hz. The technique has been used to demonstrate that MAS NMR experiments can be used to measure amorphous atomic number fractions produced by accelerated internal radiation damage. This will allow incorporated α-emitters with short half-lives to be used to model the long-term radiation tolerance of potential ceramic radioactive waste forms. This is an example of MAS NMR spectroscopy on samples containing fissionable isotopes.

  1. High-Resolution Solid-State Nuclear Magnetic Resonance Experiments on Highly Radioactive Ceramics

    SciTech Connect

    Farnan, Ian E.; Cho, Herman M.; Weber, William J.; Scheele, Randall D.; Johnson, Nigel R.; Kozelisky, Anne E.

    2004-12-01

    A triple containment magic-angle spinning rotor insert system has been developed and a sample handling procedure formulated for safety analyzing highly radioactive solids by high resolution solid state NMR. The protocol and containment system have been demonstrated for magic angle spinning (MAS) experiments on ceramic samples containing 5-10 wt% 239Pu and 238Pu at rotation speeds of 3500 Hz. The technique has been used to demonstrate that MASNMR experiments can be used to measure amorphous atomic number fractions produced during accelerated internal radioactive decay. This will allow incorporated ν-emitters with short half-lives to be used to model the long-term radiation tolerance of potential ceramic radioactive waste forms. It is believed to be the first example of MASNMR spectroscopy on samples containing fissionable isotopes.

  2. Automated NMR resonance assignment strategy for RNA via the phosphodiester backbone based on high-dimensional through-bond APSY experiments.

    PubMed

    Krähenbühl, Barbara; El Bakkali, Issam; Schmidt, Elena; Güntert, Peter; Wider, Gerhard

    2014-06-01

    A fast, robust and reliable strategy for automated sequential resonance assignment for uniformly [(13)C, (15)N]-labeled RNA via its phosphodiester backbone is presented. It is based on a series of high-dimensional through-bond APSY experiments: a 5D HCP-CCH COSY, a 4D H1'C1'CH TOCSY for ribose resonances, a 5D HCNCH for ribose-to-base connection, a 4D H6C6C5H5 TOCSY for pyrimidine resonances, and a 4D H8C8(C)C2H2 TOCSY for adenine resonances. The utilized pulse sequences are partially novel, and optimized to enable long evolution times in all dimensions. The highly precise APSY peak lists derived with these experiments could be used directly for reliable automated resonance assignment with the FLYA algorithm. This approach resulted in 98 % assignment completeness for all (13)C-(1)H, (15)N1/9 and (31)P resonances of a stem-loop with 14 nucleotides. PMID:24771326

  3. 17O and 2H NQR study of solid methanol near its melting temperature

    NASA Astrophysics Data System (ADS)

    Brett, C. R.; Edmonds, D. T.

    The nuclear quadrupole resonance of naturally abundant 17O and substituted 2H were measured in the hydroxyl bond of solid methanol (CH 3OH). By working at temperatures close to the melting point it proved possible to obtain proton spin-lattice relaxation times of several seconds in zero magnetic field. The 17O and 2H quadrupole coupling constants and the OH bond lengths measured at 150 K in the α phase and at 170 K in the β phase of methanol are listed below.

  4. A tunable general purpose Q-band resonator for CW and pulse EPR/ENDOR experiments with large sample access and optical excitation

    NASA Astrophysics Data System (ADS)

    Reijerse, Edward; Lendzian, Friedhelm; Isaacson, Roger; Lubitz, Wolfgang

    2012-01-01

    We describe a frequency tunable Q-band cavity (34 GHz) designed for CW and pulse Electron Paramagnetic Resonance (EPR) as well as Electron Nuclear Double Resonance (ENDOR) and Electron Electron Double Resonance (ELDOR) experiments. The TE 011 cylindrical resonator is machined either from brass or from graphite (which is subsequently gold plated), to improve the penetration of the 100 kHz field modulation signal. The (self-supporting) ENDOR coil consists of four 0.8 mm silver posts at 2.67 mm distance from the cavity center axis, penetrating through the plunger heads. It is very robust and immune to mechanical vibrations. The coil is electrically shielded to enable CW ENDOR experiments with high RF power (500 W). The top plunger of the cavity is movable and allows a frequency tuning of ±2 GHz. In our setup the standard operation frequency is 34.0 GHz. The microwaves are coupled into the resonator through an iris in the cylinder wall and matching is accomplished by a sliding short in the coupling waveguide. Optical excitation of the sample is enabled through slits in the cavity wall (transmission ˜60%). The resonator accepts 3 mm o.d. sample tubes. This leads to a favorable sensitivity especially for pulse EPR experiments of low concentration biological samples. The probehead dimensions are compatible with that of Bruker flexline Q-band resonators and it fits perfectly into an Oxford CF935 Helium flow cryostat (4-300 K). It is demonstrated that, due to the relatively large active sample volume (20-30 μl), the described resonator has superior concentration sensitivity as compared to commercial pulse Q-band resonators. The quality factor ( Q L) of the resonator can be varied between 2600 (critical coupling) and 1300 (over-coupling). The shortest achieved π/2-pulse durations are 20 ns using a 3 W microwave amplifier. ENDOR (RF) π-pulses of 20 μs ( 1H @ 51 MHz) were obtained for a 300 W amplifier and 7 μs using a 2500 W amplifier. Selected applications of the resonator are presented.

  5. Covalency of hydrogen bonds in liquid water can be probed by proton nuclear magnetic resonance experiments

    PubMed Central

    Elgabarty, Hossam; Khaliullin, Rustam Z.; Kühne, Thomas D.

    2015-01-01

    The concept of covalency is widely used to describe the nature of intermolecular bonds, to explain their spectroscopic features and to rationalize their chemical behaviour. Unfortunately, the degree of covalency of an intermolecular bond cannot be directly measured in an experiment. Here we established a simple quantitative relationship between the calculated covalency of hydrogen bonds in liquid water and the anisotropy of the proton magnetic shielding tensor that can be measured experimentally. This relationship enabled us to quantify the degree of covalency of hydrogen bonds in liquid water using the experimentally measured anisotropy. We estimated that the amount of electron density transferred between molecules is on the order of 10  m while the stabilization energy due to this charge transfer is ∼15 kJ mol−1. The physical insight into the fundamental nature of hydrogen bonding provided in this work will facilitate new studies of intermolecular bonding in a variety of molecular systems. PMID:26370179

  6. Beam experiments with the Grenoble test electron cyclotron resonance ion source at iThemba LABS

    NASA Astrophysics Data System (ADS)

    Thomae, R.; Conradie, J.; Fourie, D.; Mira, J.; Nemulodi, F.; Kuechler, D.; Toivanen, V.

    2016-02-01

    At iThemba Laboratory for Accelerator Based Sciences (iThemba LABS) an electron cyclotron ion source was installed and commissioned. This source is a copy of the Grenoble Test Source (GTS) for the production of highly charged ions. The source is similar to the GTS-LHC at CERN and named GTS2. A collaboration between the Accelerators and Beam Physics Group of CERN and the Accelerator and Engineering Department of iThemba LABS was proposed in which the development of high intensity argon and xenon beams is envisaged. In this paper, we present beam experiments with the GTS2 at iThemba LABS, in which the results of continuous wave and afterglow operation of xenon ion beams with oxygen as supporting gases are presented.

  7. Beam experiments with the Grenoble test electron cyclotron resonance ion source at iThemba LABS.

    PubMed

    Thomae, R; Conradie, J; Fourie, D; Mira, J; Nemulodi, F; Kuechler, D; Toivanen, V

    2016-02-01

    At iThemba Laboratory for Accelerator Based Sciences (iThemba LABS) an electron cyclotron ion source was installed and commissioned. This source is a copy of the Grenoble Test Source (GTS) for the production of highly charged ions. The source is similar to the GTS-LHC at CERN and named GTS2. A collaboration between the Accelerators and Beam Physics Group of CERN and the Accelerator and Engineering Department of iThemba LABS was proposed in which the development of high intensity argon and xenon beams is envisaged. In this paper, we present beam experiments with the GTS2 at iThemba LABS, in which the results of continuous wave and afterglow operation of xenon ion beams with oxygen as supporting gases are presented. PMID:26931949

  8. Covalency of hydrogen bonds in liquid water can be probed by proton nuclear magnetic resonance experiments.

    PubMed

    Elgabarty, Hossam; Khaliullin, Rustam Z; Kühne, Thomas D

    2015-01-01

    The concept of covalency is widely used to describe the nature of intermolecular bonds, to explain their spectroscopic features and to rationalize their chemical behaviour. Unfortunately, the degree of covalency of an intermolecular bond cannot be directly measured in an experiment. Here we established a simple quantitative relationship between the calculated covalency of hydrogen bonds in liquid water and the anisotropy of the proton magnetic shielding tensor that can be measured experimentally. This relationship enabled us to quantify the degree of covalency of hydrogen bonds in liquid water using the experimentally measured anisotropy. We estimated that the amount of electron density transferred between molecules is on the order of 10  m while the stabilization energy due to this charge transfer is ∼15 kJ mol(-1). The physical insight into the fundamental nature of hydrogen bonding provided in this work will facilitate new studies of intermolecular bonding in a variety of molecular systems. PMID:26370179

  9. Patients’ experience of outsourcing and care related to magnetic resonance examinations

    PubMed Central

    Aspelin, Peter; Bergstrand, Lott; Blomqvist, Lennart

    2014-01-01

    Background Outsourcing radiological examinations from public university hospitals affects the patient, who has to attend a different clinic or hospital for the radiological examination. We currently have a limited understanding of how patients view outsourcing and their care related to MR examinations. Aim Aim. To examine the experiences of patients who are sent to private radiology units when their referrals for MR examinations are outsourced from a university hospital, as well as to explore factors which influence patient satisfaction regarding the quality of care related to the MR examination. Methods A group of patients (n = 160) referred for MR examinations and either examined at a university hospital or at an external private unit were interviewed. The interview was designed as a verbal questionnaire. Data were analyzed using Student’s t test, analysis of variance (ANOVA), and Pearson’s correlation. Results Sixty-nine percent of the patients could neither choose nor influence the location at which they were examined. For those who could, aspects that influenced the patient’s choice of radiology department were: short waiting time 79% (127/160), ease of traveling to the radiology department 68% (110/160), and short distance to their home or work 58% (93/160). For 40% (60/160) of the patients, a short time in the waiting room was related to a positive experience of the MR examination. Conclusion Conclusion. If patients were informed about outsourcing and could also choose where to have their examination, key factors contributing to patient satisfaction could be met even when MR examinations are outsourced. PMID:25142133

  10. Drift Kinetic Effects on 3D Plasma Response in High-beta Tokamak Resonant Field Amplification Experiments

    NASA Astrophysics Data System (ADS)

    Wang, Z. R.

    2014-10-01

    Through theory and simulation of drift kinetic effects, modeling with the MARS-K code has for the first time explained the linear plasma response to 3D fields in the vicinity of the ``no-wall'' ideal beta limit. A longstanding issue in understanding resonant field amplification (RFA) of plasma to 3D fields is that the ideal magnetohydrodynamics (MHD) theory predicts an unlimited amplification near the no-wall stability limit. However, in many experiments such as DIID-D and NSTX, the plasma response increases almost monotonically along with the plasma beta across the ideally predicted no-wall limit. This disagreement is now explained by perturbed drift kinetic theory and associated with distorted particle orbits by 3D fields. The upgraded MARS-K code, which has the capability to solve linearized hybrid MHD equations with drift kinetic effects self-consistently, is applied to study the DIII-D RFA experiments through the quantitative comparison. It reveals the kinetic effect due to thermal particles plays a major role in modifying the response structure throughout plasma and keeps the finite amplification of response, as the experimental measurements, around the no-wall beta limit. The perturbed energy analysis shows the modification of plasma response is mainly contributed by the precession, bounce and transit resonances of thermal ions. The kinetic effect of isotropic energetic particles with slowing down distribution can further slightly change the plasma response without significant contribution. RFA experiments in NSTX plasmas are also analyzed to affirm the role of drift kinetic effect on modifying the plasma response. This study shows good agreements between theoretical results and various RFA experimental measurements, providing the possible physics explanation of RFA phenomena observed in many tokamaks. The results also indicate the validity of self-consistent calculation of hybrid drift kinetic-MHD model with drift kinetic effect in high beta tokamaks. Supported by the US DOE under DE-AC02-09CH11466 & DE-FC02-04ER54698.

  11. Real time polarization monitor developed for high power electron cyclotron resonance heating and current drive experiments in large helical device

    SciTech Connect

    Notake, T.; Idei, H.; Kubo, S.; Shimozuma, T.; Yoshimura, Y.; Kobayashi, S.; Mizuno, Y.; Ito, S.; Takita, Y.; Ohkubo, K.; Kasparek, W.; Watari, T.; Kumazawa, R.

    2005-02-01

    The polarization state of a wave is an important factor in electron cyclotron resonance heating (ECRH) and current drive (ECCD), for it strongly affects the propagation and absorption of the wave in the plasma. A real-time monitor of the polarization of the EC beam has been developed for use in ECRH/ECCD experiments in large helical device (LHD). Two orthogonal components of the wave field are measured in one of the miter-bends by use of a specially designed coupler and a waveguide circuit with a 0 deg. -90 deg. phase switch to deduce the polarization parameters: the polarization angle {alpha} and the ellipticity {beta}. Since fast-response pin diodes are used for the switches, the polarization is determined every 3 ms, facilitating real time acquisition of the polarization. This article reports on the design and the principle of this monitor as well as on the algorithm used to calculate {alpha} and {beta}. This article also reports on the method of calibration, for the accuracy of this measurement depends on it. Finally, a comparison is made between polarization parameters measured by a monitor actually installed on one of the ECRH transmission lines on LHD and the value set by the polarizer in ECRH experiments.

  12. The effect of observer experience on magnetic resonance imaging interpretation and localization of triangular fibrocartilage complex lesions.

    PubMed

    Blazar, P E; Chan, P S; Kneeland, J B; Leatherwood, D; Bozentka, D J; Kowalchick, R

    2001-07-01

    This study investigates the effect of experience of the interpreter on the ability of magnetic resonance imaging (MRI) to identify the presence and anatomic location of a triangular fibrocartilage complex (TFCC) lesion. Fifty-one patients who underwent wrist arthroscopy with preoperative MRI studies were reviewed retrospectively. Two radiologists with different levels of training and experience evaluated the MRI scans in a blinded manner. The sensitivity rates of the 2 observers for detection of TFCC lesions were 86% and 80%. The specificity rates were 96% and 80%. The accuracy rates for prediction of a TFCC tear were 83% and 61% for the 2 observers. The correct location of a TFCC lesion was predicted by the more experienced observer for 12 of 19 central, 3 of 4 radial, and 6 of 12 peripheral lesions. The less experienced observer correctly identified 8 of 19 central, 2 of 4 radial, and 2 of 12 peripheral tears. The overall accuracy rates for prediction of a TFCC lesion and its location were 69% and 37%. Our data indicate that the published accuracy rates for prediction of TFCC lesion location may be reproducible only in very specialized centers. PMID:11466652

  13. Low-energy physical properties of high- Tc superconducting Cu oxides: A comparison between the resonating valence bond and experiments

    NASA Astrophysics Data System (ADS)

    Yang, Kai-Yu; Shih, C. T.; Chou, C. P.; Huang, S. M.; Lee, T. K.; Xiang, T.; Zhang, F. C.

    2006-06-01

    In a recent review by Anderson and co-workers, it was pointed out that an early resonating valence bond (RVB) theory is able to explain a number of unusual properties of high-temperature superconducting (SC) Cu oxides. Here we extend previous calculations to study more systematically the low-energy physical properties of the plain vanilla d -wave RVB state, and to compare the results with the available experiments. We use a renormalized mean-field theory combined with variational Monte Carlo and power Lanczos methods to study the RVB state of an extended t-J model in a square lattice with parameters suitable for the hole-doped Cu oxides. The physical observable quantities we study include the specific heat, the linear residual thermal conductivity, the in-plane magnetic penetration depth, the quasiparticle energy at the antinode (π,0) , the superconducting energy gap, the quasiparticle spectra, and the Drude weights. The traits of nodes (including kF , the Fermi velocity vF , and the velocity along Fermi surface v2 ), and the SC order parameter are studied. Comparisons of the theory and the experiments in cuprates show an overall qualitative agreement, especially on their doping dependences.

  14. Dynamics of cross polarization in solid state nuclear magnetic resonance experiments of amorphous and heterogeneous natural organic substances.

    PubMed

    Conte, Pellegrino; Berns, Anne E

    2008-09-01

    Nuclear magnetic resonance (NMR) experiments on carbon-13 in the solid state were done with cross polarization (CP) and magic angle spinning (MAS) in order to overcome the low NMR sensitivity of (13)C and the chemical shift anisotropy, respectively. In the present research, CPMAS (13)C-NMR spectra were collected by modulating the contact time needed for cross polarization (variable contact times experiments, VCT) on two different humic acids (a soil-HA and a coal-HA). VCT data were fitted by a model containing either a monotonic or a non-monotonic cross polarization term. The non-monotonic model, which fitted the experimental results better than the monotonic one, provided two cross-polarization rates, thereby suggesting that two different mechanisms for the energy transfer from protons to carbons arise in amorphous and heterogeneous humic substances. The first mechanism was a fast proton-to-carbon energy transfer due to protons directly bound to carbons. The second mechanism was related to a slow transfer mediated by local segmental motions. Different domains in the humic acids were identified. Soil-HA was made of rigid domains, containing mainly aromatic and carboxylic moieties, and fast moving domains, containing alkyl, C-O and C-O groups. Coal-HA showed a rigid aromatic domain that was differentiated from a very mobile domain made of alkyl and COOH groups. PMID:18781033

  15. Stochastic resonance

    NASA Astrophysics Data System (ADS)

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

    1998-01-01

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

  16. Tautomerism and possible polymorphism in solid hydroxypyridines and pyridones studied by 14N NQR.

    PubMed

    Seliger, Janez; Žagar, Veselko

    2013-02-21

    (14)N nuclear quadrupole resonance frequencies have been measured in solid 2-pyridone, 3-hydroxypyridine, and 4-pyridone by (1)H-(14)N nuclear quadrupole double resonance. Two slightly nonequivalent nitrogen positions are observed in solid 3-hydroxypyridine, whereas only one nitrogen position has been observed in 2-pyridone and 4-pyridone within the experimental resolution. Rather low (14)N quadrupole coupling constants in pyridones are the consequence of the delocalization of the nitrogen lone pair electrons in the aromatic rings. Two different compounds have been obtained by crystallization of 4-pyridone from ethanol in a normal and in a dry atmosphere. The compound obtained in the dry atmosphere is identical to the commercial sample. The compound obtained in the normal atmosphere cannot be converted to the commercial polymorph by melting. It is thus not a polymorph of anhydrous 4-pyridone. The temperature coefficient of the (14)N quadrupole coupling constant is negative in 3-hydroxypyridine and positive in 2- and 4-pyridone. Therefore, in 3-hydroxypyridine, molecular librations dominate the temperature variation of the quadrupole coupling constant, whereas in 2- and 4-pyridone, the changes in the hydrogen bonding interactions with temperature seem to give the dominant effect. PMID:23347232

  17. 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.

  18. Field experiment provides ground truth for surface nuclear magnetic resonance measurement

    USGS Publications Warehouse

    Knight, R.; Grunewald, E.; Irons, T.; Dlubac, K.; Song, Y.; Bachman, H.N.; Grau, B.; Walsh, D.; Abraham, J.D.; Cannia, J.

    2012-01-01

    The need for sustainable management of fresh water resources is one of the great challenges of the 21st century. Since most of the planet's liquid fresh water exists as groundwater, it is essential to develop non-invasive geophysical techniques to characterize groundwater aquifers. A field experiment was conducted in the High Plains Aquifer, central United States, to explore the mechanisms governing the non-invasive Surface NMR (SNMR) technology. We acquired both SNMR data and logging NMR data at a field site, along with lithology information from drill cuttings. This allowed us to directly compare the NMR relaxation parameter measured during logging, T 2, to the relaxation parameter T 2 * measured using the SNMR method. The latter can be affected by inhomogeneity in the magnetic field, thus obscuring the link between the NMR relaxation parameter and the hydraulic conductivity of the geologic material. When the logging T 2 data were transformed to pseudo-T 2 * data, by accounting for inhomogeneity in the magnetic field and instrument dead time, we found good agreement with T 2 * obtained from the SNMR measurement. These results, combined with the additional information about lithology at the site, allowed us to delineate the physical mechanisms governing the SNMR measurement. Such understanding is a critical step in developing SNMR as a reliable geophysical method for the assessment of groundwater resources. Copyright 2012 by the American Geophysical Union.

  19. Proton and deuterium NMR experiments in zero field. [Perdeuterated p-demethoxybenzene, perdeuterated malonic acid, diethyl terephthalate-d4, nonadecane-2,2'-D2, sodium propionate-D2

    SciTech Connect

    Millar, J.M.

    1986-02-01

    High field solid-state NMR lineshapes suffer from inhomogeneous broadening since resonance frequencies are a function of molecular orientation. Time domain zero field NMR is a two-dimensional field-cycling technique which removes this broadening by probing the evolution of the spin system under zero applied field. The simplest version, the sudden transition experiment, induces zero field evolution by the sudden removal of the applied magnetic field. Theory and experimental results of this experiment and several variations using pulsed dc magnetic fuelds to initiate zero field evolution are presented. In particular, the pulsed indirect detection method allows detection of the zero field spectrum of one nuclear spin species via another (usually protons) by utilizing the level crossings which occur upon adiabatic demagnetization to zero field. Experimental examples of proton/deuteron systems are presented which demonstrate the method results in enhanced sensitivity relative to that obtained in sudden transition experiments performed directly on deuterium. High resolution /sup 2/H NQR spectra of a series of benzoic acid derivatives are obtained using the sudden transition and indirect detection methods. Librational oscillations in the water molecules of barium chlorate monohydrate are studied using proton and deuterium ZF experiments. 177 refs., 88 figs., 2 tabs.

  20. SU-E-J-181: Magnetic Resonance Image-Guided Radiation Therapy Workflow: Initial Clinical Experience

    SciTech Connect

    Green, O; Kashani, R; Santanam, L; Wooten, H; Li, H; Rodriguez, V; Hu, Y; Mutic, S; Hand, T; Victoria, J; Steele, C

    2014-06-01

    Purpose: The aims of this work are to describe the workflow and initial clinical experience treating patients with an MRI-guided radiotherapy (MRIGRT) system. Methods: Patient treatments with a novel MR-IGRT system started at our institution in mid-January. The system consists of an on-board 0.35-T MRI, with IMRT-capable delivery via doubly-focused MLCs on three {sup 60} Co heads. In addition to volumetric MR-imaging, real-time planar imaging is performed during treatment. So far, eleven patients started treatment (six finished), ranging from bladder to lung SBRT. While the system is capable of online adaptive radiotherapy and gating, a conventional workflow was used to start, consisting of volumetric imaging for patient setup using visible tumor, evaluation of tumor motion outside of PTV on cine images, and real-time imaging. Workflow times were collected and evaluated to increase efficiency and evaluate feasibility of adding the adaptive and gating features while maintaining a reasonable patient throughput. Results: For the first month, physicians attended every fraction to provide guidance on identifying the tumor and an acceptable level of positioning and anatomical deviation. Average total treatment times (including setup) were reduced from 55 to 45 min after physician presence was no longer required and the therapists had learned to align patients based on soft-tissue imaging. Presently, the source strengths were at half maximum (7.7K Ci each), therefore beam-on times will be reduced after source replacement. Current patient load is 10 per day, with increase to 25 anticipated in the near future. Conclusion: On-board, real-time MRI-guided RT has been incorporated into clinical use. Treatment times were kept to reasonable lengths while including volumetric imaging, previews of tumor movement, and physician evaluation. Workflow and timing is being continuously evaluated to increase efficiency. In near future, adaptive and gating capabilities of the system will be implemented.

  1. NMR and NQR study of Si-doped (6,0) zigzag single-walled aluminum nitride nanotube as n or P-semiconductors.

    PubMed

    Baei, Mohammad T; Peyghan, Ali Ahmadi; Tavakoli, Khadijeh; Babaheydari, Ali Kazemi; Moghimi, Masoumeh

    2012-09-01

    Density functional theory (DFT) calculations were performed to investigate the electronic structure properties of pristine and Si-doped aluminum nitride nanotubes as n or P-semiconductors at the B3LYP/6-31G* level of theory in order to evaluate the influence of Si-doped in the (6,0) zigzag AlNNTs. We extended the DFT calculation to predict the electronic structure properties of Si-doped aluminum nitride nanotubes, which are very important for production of solid-state devices and other applications. To this aim, pristine and Si-doped AlNNT structures in two models (Si(N) and Si(Al)) were optimized, and then the electronic properties, the isotropic (CS(I)) and anisotropic (CS(A)) chemical shielding parameters for the sites of various (27)Al and (14)N atoms, NQR parameters for the sites of various of (27)Al and (14)N atoms, and quantum molecular descriptors were calculated in the optimized structures. The optimized structures, the electronic properties, NMR and NQR parameters, and quantum molecular descriptors for the Si(N) and Si(Al) models show that the Si(N) model is a more reactive material than the pristine or Si(Al) model. PMID:22588584

  2. High-resolution nuclear magnetic resonance measurements in inhomogeneous magnetic fields: A fast two-dimensional J-resolved experiment.

    PubMed

    Huang, Yuqing; Lin, Yung-Ya; Cai, Shuhui; Yang, Yu; Sun, Huijun; Lin, Yanqin; Chen, Zhong

    2016-03-14

    High spectral resolution in nuclear magnetic resonance (NMR) is a prerequisite for achieving accurate information relevant to molecular structures and composition assignments. The continuous development of superconducting magnets guarantees strong and homogeneous static magnetic fields for satisfactory spectral resolution. However, there exist circumstances, such as measurements on biological tissues and heterogeneous chemical samples, where the field homogeneity is degraded and spectral line broadening seems inevitable. Here we propose an NMR method, named intermolecular zero-quantum coherence J-resolved spectroscopy (iZQC-JRES), to face the challenge of field inhomogeneity and obtain desired high-resolution two-dimensional J-resolved spectra with fast acquisition. Theoretical analyses for this method are given according to the intermolecular multiple-quantum coherence treatment. Experiments on (a) a simple chemical solution and (b) an aqueous solution of mixed metabolites under externally deshimmed fields, and on (c) a table grape sample with intrinsic field inhomogeneity from magnetic susceptibility variations demonstrate the feasibility and applicability of the iZQC-JRES method. The application of this method to inhomogeneous chemical and biological samples, maybe in vivo samples, appears promising. PMID:26979686

  3. Application of quantitative (19) F nuclear magnetic resonance spectroscopy in tape-stripping experiments with natural microemulsions.

    PubMed

    Schwarz, Julia C; Hoppel, Magdalena; Kählig, Hanspeter; Valenta, Claudia

    2013-08-01

    The skin penetration of flufenamic acid (Fluf) and fluconazole (Fluc) from innovative natural microemulsions was investigated in tape-stripping experiments on pig ears. The formulations were based on the eudermic surfactants lecithin, sucrose laurate, alkylpolyglycoside or a mixture thereof. The quantification of the penetrated drug amounts was executed by (19) F nuclear magnetic resonance (NMR) in comparison with high-performance liquid chromatography (HPLC). The data obtained by the (19) F NMR method were confirmed by additional quantitative studies using HPLC. An excellent linear correlation was found for Fluf as well as for Fluc between (19) F NMR and HPLC data. This work presents a strategy outlining the use of (19) F NMR to selectively monitor the skin penetration routes of fluorinated compounds. Fluc penetrated generally well into the stratum corneum with the significantly highest amounts from the sucrose laurate microemulsion on the tape strips 1-5. Similarly, the highest amounts of penetrated Fluf could be observed from the formulation based on sucrose laurate. In addition, NMR self-diffusion studies were conducted and revealed a bicontinuous microstructure of the investigated microemulsions. The skin penetration results are in good agreement with the obtained (19) F NMR self-diffusion coefficients of the active compounds in the microemulsion systems. PMID:23794482

  4. Design and fabrication of circular and rectangular components for electron-cyclotron-resonant heating of tandem mirror experiment-upgrade

    SciTech Connect

    Felker, B.; Calderon, M.O.; Chargin, A.K.; Coffield, F.E.; Lang, D.D.; Rubert, R.R.; Pedrotti, L.R.; Stallard, B.W.; Gallagher, N.C. Jr.; Sweeney, D.W.

    1983-11-18

    The electron-cyclotron-resonant heating (ECRH) systems of rectangular waveguides on Tandem Mirror Experiment-Upgrade (TMX-U) operated with a overall efficiency of 50%, each system using a 28-GHz, 200-kW pulsed gyrotron. We designed and built four circular-waveguide systems with greater efficiency and greater power-handling capabilities to replace the rectangular waveguides. Two of these circular systems, at the 5-kG second-harmonic heating locations, have a total transmission efficiency of >90%. The two systems at the 10-kG fundamental heating locations have a total transmission efficiency of 80%. The difference in efficiency is due to the additional components required to launch the microwaves in the desired orientation and polarization with respect to magnetic-field lines at the 10-kG points. These systems handle the total power available from each gyrotron but do not have the arcing limitation problem of the rectangular waveguide. Each system requires several complex components. The overall physical layout and the design considerations for the rectangular and circular waveguide components are described here.

  5. Theory and experiments of disorder-induced resonance shifts and mode-edge broadening in deliberately disordered photonic crystal waveguides

    NASA Astrophysics Data System (ADS)

    Mann, Nishan; Javadi, Alisa; García, P. D.; Lodahl, Peter; Hughes, Stephen

    2015-08-01

    We study both theoretically and experimentally the effects of introducing deliberate disorder in a slow-light photonic crystal waveguide on the photon density of states. We introduce a theoretical model that includes both deliberate disorder through statistically moving the hole centers in the photonic crystal lattice and intrinsic disorder caused by fabrication imperfections. We demonstrate a disorder-induced mean blueshift and an overall broadening of the photonic density of states for deliberate disorder values ranging 0-12 nm. By comparing with measurements obtained from a GaAs photonic crystal waveguide, we find very good agreement between theory and experiment. These results highlight the importance of carefully including local field effects for modeling high-index contrast perturbations and demonstrate the efficiency of our perturbative approach for modeling disorder-induced changes in the density of states. Our work also demonstrates the importance of using asymmetric dielectric polarizabilities for positive and negative dielectric perturbations when modeling a perturbed dielectric interface in photonic crystal platforms. Finally, we also show examples of disorder-induced resonances that can appear for various instances of disorder.

  6. High-resolution nuclear magnetic resonance measurements in inhomogeneous magnetic fields: A fast two-dimensional J-resolved experiment

    NASA Astrophysics Data System (ADS)

    Huang, Yuqing; Lin, Yung-Ya; Cai, Shuhui; Yang, Yu; Sun, Huijun; Lin, Yanqin; Chen, Zhong

    2016-03-01

    High spectral resolution in nuclear magnetic resonance (NMR) is a prerequisite for achieving accurate information relevant to molecular structures and composition assignments. The continuous development of superconducting magnets guarantees strong and homogeneous static magnetic fields for satisfactory spectral resolution. However, there exist circumstances, such as measurements on biological tissues and heterogeneous chemical samples, where the field homogeneity is degraded and spectral line broadening seems inevitable. Here we propose an NMR method, named intermolecular zero-quantum coherence J-resolved spectroscopy (iZQC-JRES), to face the challenge of field inhomogeneity and obtain desired high-resolution two-dimensional J-resolved spectra with fast acquisition. Theoretical analyses for this method are given according to the intermolecular multiple-quantum coherence treatment. Experiments on (a) a simple chemical solution and (b) an aqueous solution of mixed metabolites under externally deshimmed fields, and on (c) a table grape sample with intrinsic field inhomogeneity from magnetic susceptibility variations demonstrate the feasibility and applicability of the iZQC-JRES method. The application of this method to inhomogeneous chemical and biological samples, maybe in vivo samples, appears promising.

  7. Interobserver variability of magnetic resonance angiography in the diagnosis of carotid stenosis--effect of observer experience.

    PubMed

    Wardlaw, J M; Lewis, S C; Collie, D A; Sellar, R

    2002-02-01

    Magnetic resonance angiography (MRA) for determining the degree of carotid stenosis prior to carotid endarterectomy is attractive because it does not have the high morbidity associated with conventional intra-arterial angiography. We assessed the interobserver variability in the estimation of the degree of stenosis amongst observers of different experience. In a prospective study, consecutive patients with transient ischaemic attacks and symptomatic tight carotid stenosis shown by Doppler ultrasound underwent conventional intra-arterial angiography and 2-D and 3-D time-of-flight MRA of the carotid bifurcations. The films of the processed MRA images were reviewed blind to other clinical and imaging data by eight observers of different levels of experience and coded for the presence and degree of stenosis. The stenosis on intra-arterial angiography was used as the reference standard. There was considerable variability between observers for estimation of the degree of stenosis on MRA. The observers' accuracy ranged from 41% (student) to 79% (experienced). From these estimations, excluding those of the student, it could be seen that up to 23% of patients who would have had an endarterectomy based on MRA should not have done so according to angiography, and up to 33% of patients who should have had an endarterectomy according to angiography would have inappropriately missed having an endarterectomy based on MRA results. Observer reliability of MRA processed images is not good, even in experienced hands. Using the source images and views of the circle of Willis might improve the accuracy, but a further study is required to assess this. PMID:11942364

  8. A zero-field NQR and low-field NMR study of NaHF 2 and KHF 2

    NASA Astrophysics Data System (ADS)

    Gosling, P.; Edmonds, D. T.; Rabbani, S. R.

    The quadrupole coupling constants and asymmetry parameters have been measured for 23Na in NaHF 2 and NaDF 2 and an estimate obtained for the quadrupole coupling constant of 39K in KHF 2 using nuclear quadrupole double-resonance (NQDR) techniques. Both fluorine and hydrogen were used as the detecting nuclear species. Using the same field-cycling techniques as are used in NQDR the very low field NMR of the HF2- ion was measured. By a comparison of theory with experiment it was possible to deduce a F-H bond length of 0.115(1) nm for KHF 2 and 0.113(l) nm for NaHF 2.

  9. Study of plasma start-up initiated by second harmonic electron cyclotron resonance heating on WEGA experiment

    SciTech Connect

    Preynas, M.; Laqua, H. P.; Otte, M.; Stange, T.; Aßmus, D.; Wauters, T.

    2014-02-12

    Although both 1st harmonic ordinary mode (O1) and 2nd harmonic extra-ordinary mode (X2) have been successfully used to initiate pre-ionization and breakdown in many devices, a complete theoretical model is still missing to explain the success of this method. Moreover, some experimental observations are not completely understood, such as what occurs during the delay time between the turn-on of ECRH power and first signals of density or light measurements. Since during this free period the ECRH power has to be absorbed by in-vessel components, it is of prime importance to know what governs this delay time. Recently, dedicated start-up experiments have been performed on WEGA, using a 28 GHz ECRH system in X2-mode. This machine has the interesting capability to be run also as a tokamak allowing comparative experiments between stellarator (ι/2π > 0) and tokamak (ι/2π = 0) configurations. Different scans in heating power, neutral gas pressure, and rotational transform (ι) show clearly that the start-up is a two step process. A first step following the turn-on of the ECRH power during which no measurable electron density (or just above the noise level in some cases), ECE and radiated power is detected. Its duration depends strongly on the level of injected power. The second step corresponds to the gas ionization and plasma expansion phase, with a velocity of density build-up and filling-up of the vessel volume depending mainly on pressure, gas and rotational transform. Moreover, an interesting scenario of ECRH pre-ionization without loop voltage in tokamak configuration by applying a small optimal vertical field is relevant for start-up assistance on future experiments like ITER. The results from this experimental parametric study are useful for the modeling of the start-up assisted by the second harmonic electron cyclotron resonance heating. The aim of this work is to establish predictive scenarios for both ITER and W7-X operation.

  10. Study of plasma start-up initiated by second harmonic electron cyclotron resonance heating on WEGA experiment

    NASA Astrophysics Data System (ADS)

    Preynas, M.; Laqua, H. P.; Otte, M.; Stange, T.; Wauters, T.; Aßmus, D.

    2014-02-01

    Although both 1st harmonic ordinary mode (O1) and 2nd harmonic extra-ordinary mode (X2) have been successfully used to initiate pre-ionization and breakdown in many devices, a complete theoretical model is still missing to explain the success of this method. Moreover, some experimental observations are not completely understood, such as what occurs during the delay time between the turn-on of ECRH power and first signals of density or light measurements. Since during this free period the ECRH power has to be absorbed by in-vessel components, it is of prime importance to know what governs this delay time. Recently, dedicated start-up experiments have been performed on WEGA, using a 28 GHz ECRH system in X2-mode. This machine has the interesting capability to be run also as a tokamak allowing comparative experiments between stellarator (ι/2π > 0) and tokamak (ι/2π = 0) configurations. Different scans in heating power, neutral gas pressure, and rotational transform (ι) show clearly that the start-up is a two step process. A first step following the turn-on of the ECRH power during which no measurable electron density (or just above the noise level in some cases), ECE and radiated power is detected. Its duration depends strongly on the level of injected power. The second step corresponds to the gas ionization and plasma expansion phase, with a velocity of density build-up and filling-up of the vessel volume depending mainly on pressure, gas and rotational transform. Moreover, an interesting scenario of ECRH pre-ionization without loop voltage in tokamak configuration by applying a small optimal vertical field is relevant for start-up assistance on future experiments like ITER. The results from this experimental parametric study are useful for the modeling of the start-up assisted by the second harmonic electron cyclotron resonance heating. The aim of this work is to establish predictive scenarios for both ITER and W7-X operation.

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

    SciTech Connect

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

    2011-03-01

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

  12. 75As and 139La NMR/NQR investigations of iron-based superconductor LaFeAs(O0.89F0.11)

    NASA Astrophysics Data System (ADS)

    Nakai, Y.; Kitagawa, S.; Ishida, K.; Kamihara, Y.; Hirano, M.; Hosono, H.

    2009-03-01

    We report 75As and 139La NMR/NQR results in LaFeAs(O0.89F0.11). In the normal state, 1/T1T decreases with lowered temperature, which is reminiscent of the pseudogap behavior in the high-Tc cuprates. In the superconducting (SC) state, 1/T1 decreases suddenly below Tc without a Hebel-Slichter coherence peak, followed by a T3 dependence, which is characteristics of unconventional superconductors with lines of nodes. However, the residual density of states in the low temperatures, which is usually observed in unconventional superconductors with crystal imperfections and/or impurity phases, was not observed. Knight shift measurements show that spin susceptibility decreases in the SC state.

  13. Improved apparatus for trapped radical and other studies down to 1.5 K. [microwave cavity cryogenic equipment for electron paramagnetic resonance experiments

    NASA Technical Reports Server (NTRS)

    Woollam, J. A.; Sugawara, K.

    1978-01-01

    A Dewar system and associated equipment for electron paramagnetic resonance (EPR) studies of trapped free radicals and other optical or irradiation experiments are described. The apparatus is capable of reaching a temperature of 1.5 K and transporting on the order of 20 W per K temperature gradient; its principal advantages are for use at pumped cryogen temperatures and for experiments with large heat inputs. Two versions of the apparatus are discussed, one of which is designed for EPR in a rectangular cavity operating in a TE(102) mode and another in which EPR is performed in a cylindrical microwave cavity.

  14. [Frontotemporal degeneration: a clinical case and experience of using of diffusion tensor magnetic-resonance imaging tractography].

    PubMed

    Kulesh, A A; Drobakha, V E; Shestakov, V V; Lapaeva, T V; Dementeva, O V

    2015-01-01

    Frontotemporal degeneration is a frequent cause of presenile dementia that makes up from 5 to 17% of autopsy-confirmed cases developed at the age of 70 years. Authors report a case of this disease, discuss the possible causes of its development and present the results of diffusion tensor magnetic resonance tractography. Clinical features of this case are practically isolated speech disturbance with the most likely domination of a semantic variant of primary progressive aphasia. Magnetic-resonance imaging has an important practical significance for this pathology due to the possibility of assessing atrophic zones. The use of DTI-tractography allows to extend diagnostic possibilities. PMID:26978060

  15. Surface-Enhanced Resonance Raman Scattering and Visible Extinction Spectroscopy of Copper Chlorophyllin: An Upper Level Chemistry Experiment

    ERIC Educational Resources Information Center

    Schnitzer, Cheryl S.; Reim, Candace Lawson; Sirois, John J.; House, Paul G.

    2010-01-01

    Advanced chemistry students are introduced to surface-enhanced resonance Raman scattering (SERRS) by studying how sodium copper chlorophyllin (CuChl) adsorbs onto silver colloids (CuChl/Ag) as a function of pH. Using both SERRS and visible extinction spectroscopy, the extent of CuChl adsorption and colloidal aggregation are monitored. Initially at

  16. Surface-Enhanced Resonance Raman Scattering and Visible Extinction Spectroscopy of Copper Chlorophyllin: An Upper Level Chemistry Experiment

    ERIC Educational Resources Information Center

    Schnitzer, Cheryl S.; Reim, Candace Lawson; Sirois, John J.; House, Paul G.

    2010-01-01

    Advanced chemistry students are introduced to surface-enhanced resonance Raman scattering (SERRS) by studying how sodium copper chlorophyllin (CuChl) adsorbs onto silver colloids (CuChl/Ag) as a function of pH. Using both SERRS and visible extinction spectroscopy, the extent of CuChl adsorption and colloidal aggregation are monitored. Initially at…

  17. MC generator TAUOLA: Implementation of resonance chiral theory for two and three meson modes. Comparison with experiment

    SciTech Connect

    Shekhovtsova, O.; Nugent, I. M.; Przedzinski, T.; Roig, P.; Was, Z.

    2012-10-23

    We present a partial upgrade of the Monte Carlo event generator TAUOLA with the two and three hadron decay modes using the theoretical models based on Resonance Chiral Theory. These modes account for 88% of total hadronic width of the tau meson. First results of the model parameters have been obtained using BaBar data for 3{pi} mode.

  18. Long-lived frequency shifts observed in a magnetic resonance force microscope experiment following microwave irradiation of a nitroxide spin probe

    SciTech Connect

    Chen, Lei; Longenecker, Jonilyn G.; Moore, Eric W.; Marohn, John A.

    2013-04-01

    We introduce a spin-modulation protocol for force-gradient detection of magnetic resonance that enables the real-time readout of longitudinal magnetization in an electron spin resonance experiment involving fast-relaxing spins. We applied this method to observe a prompt change in longitudinal magnetization following the microwave irradiation of a nitroxide-doped perdeuterated polystyrene film having an electron spin-lattice relaxation time of T{sub 1}{approx}1ms. The protocol allowed us to discover a large, long-lived cantilever frequency shift. Based on its magnitude, lifetime, and field dependence, we tentatively attribute this persistent signal to deuteron spin magnetization created via transfer of polarization from nitroxide spins.

  19. The detection of weak heteronuclear coupling between spin 1 and spin 1/2 nuclei in MAS NMR; 14N/ 13C/ 1H triple resonance experiments

    NASA Astrophysics Data System (ADS)

    Grey, C. P.; Veeman, W. S.

    1992-05-01

    Magic angle spinning and 14N irradiation have been employed to perturb the 14N spin bath, in a new spin-echo triple resonance solid-state NMR experiment. Spinning introduces a time dependence in the 14N quadrupolar interaction, permitting transitions between the three | I, m> states, two or four times per rotor cycle; this alters the evolution of a 14N-coupled 13C spin. The reduction in 13C echo intensity, on 14N irradiation during the echo period, is greater for shorter CN distances. Irradiation at a constant frequency is more effective than sweeping through the 14N resonance. 14N double-quantum spectra are obtained indirectly by irradiation of the double-quantum transition.

  20. 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.

  1. Experiments on multiple-receiver magnetic resonance-based wireless power transfer in low megahertz with metamaterials

    NASA Astrophysics Data System (ADS)

    Kang, Le; Hu, Yuli; Zheng, Wei

    2016-04-01

    In this paper, an efficient magnetic resonance-based wireless power transfer (MRWPT) system with metamaterials is proposed. The negative permeability (MNG) metamaterials for this system with low-megahertz frequency is designed, which can be adjusted to work well at a variable receiving angle ranging from 0° to 45° along z-direction. The S-parameters, resonant frequency and permeability of metamaterials are computed for analysis. The transmission efficiency of the multiple-receiver MRWPT system in free space is compared to that in the presence of metamaterials placed in front of transmission and receive coils. The measured results show that the performance of the proposed metamaterials is perfect in improving the efficiency with incident electromagnetic waves from various directions.

  2. Early experience with X-ray magnetic resonance fusion for low-flow vascular malformations in the pediatric interventional radiology suite.

    PubMed

    Hwang, Tiffany J; Girard, Erin; Shellikeri, Sphoorti; Setser, Randolph; Vossough, Arastoo; Ho-Fung, Victor; Cahill, Anne Marie

    2016-03-01

    This technical innovation describes our experience using an X-ray magnetic resonance fusion (XMRF) software program to overlay 3-D MR images on real-time fluoroscopic images during sclerotherapy procedures for vascular malformations at a large pediatric institution. Five cases have been selected to illustrate the application and various clinical utilities of XMRF during sclerotherapy procedures as well as the technical limitations of this technique. The cases demonstrate how to use XMRF in the interventional suite to derive additional information to improve therapeutic confidence with regards to the extent of lesion filling and to guide clinical management in terms of intraprocedural interventional measures. PMID:26681438

  3. Resonance spectrum and dissociation dynamics of ozone in the 3B2 electronically excited state: experiment and theory.

    PubMed

    Deppe, Sabine F; Wachsmuth, Uwe; Abel, Bernd; Bittererov, Martina; Grebenshchikov, Sergy Yu; Siebert, Rdiger; Schinke, Reinhard

    2004-09-15

    The rovibrational spectrum assigned to the low-lying (3)B(2) electronic state of ozone is measured with intracavity laser absorption spectroscopy. The experimental results are interpreted by means of quantum dynamical calculations on a global ab initio potential energy surface. The observed spectrum is shown to originate from the vibrational ground state in the local minimum of the (3)B(2) potential. The spectrum of short-lived resonance states in this local minimum is analyzed. Additionally, the global minimum of the surface is shown to lie in the dissociation channel in the van der Waals region. This region supports a short sequence of weakly bound vibrational states. PMID:15352812

  4. ¹⁴N 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, Laouès; Marande, Pierre-Louis; Canet, Daniel

    2015-01-01

    As demonstrated before, the application of a weak static B0 magnetic field (less than 10 G) may produce definite effects on the ¹⁴N 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 0.5 G), 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

  5. 3 Tesla magnetic resonance spectroscopy: cerebral gliomas vs. metastatic brain tumors. Our experience and review of the literature.

    PubMed

    Caivano, R; Lotumolo, A; Rabasco, P; Zandolino, A; D'Antuono, F; Villonio, A; Lancellotti, M I; Macarini, L; Cammarota, A

    2013-08-01

    The aim of the present study is to report about the value of magnetic resonance spectroscopy (MRS) in differentiating brain metastases, primary high-grade gliomas (HGG) and low-grade gliomas (LGG). MRI (magnetic resonance imaging) and MRS were performed in 60 patients with histologically verified brain tumors: 32 patients with HGG (28 glioblastomas multiforme [GBM] and 4 anaplastic astrocytomas), 14 patients with LGG (9 astrocytomas and 5 oligodendrogliomas) and 14 patients with metastatic brain tumors. The Cho/Cr (choline-containing compounds/creatine-phosphocreatine complex), Cho/NAA (N-acetyl aspartate) and NAA/Cr ratios were assessed from spectral maps in the tumoral core and peritumoral edema. The differences in the metabolite ratios between LGG, HGG and metastases were analyzed statistically. Lipids/lactate contents were also analyzed. Significant differences were noted in the tumoral and peritumoral Cho/Cr, Cho/NAA and NAA/Cr ratios between LGG, HGG and metastases. Lipids and lactate content revealed to be useful for discriminating gliomas and metastases. The results of this study demonstrate that MRS can differentiate LGG, HGG and metastases, therefore diagnosis could be allowed even in those patients who cannot undergo biopsy. PMID:23390934

  6. Sequential backbone assignment of uniformly 13C-labeled RNAs by a two-dimensional P(CC)H-TOCSY triple resonance NMR experiment.

    PubMed

    Wijmenga, S S; Heus, H A; Leeuw, H A; Hoppe, H; van der Graaf, M; Hilbers, C W

    1995-01-01

    A new 1H-13C-31P triple resonance experiment is described which allows unambiguous sequential backbone assignment in 13C-labeled oligonucleotides via through-bond coherence transfer from 31P via 13C to 1H. The approach employs INEPT to transfer coherence from 31P to 13C and homonuclear TOCSY to transfer the 13C coherence through the ribose ring, followed by 13C to 1H J-cross-polarisation. The efficiencies of the various possible transfer pathways are discussed. The most efficient route involves transfer of 31Pi coherence via C4'i and C4'i-1, because of the relatively large JPC4' couplings involved. Via the homonuclear and heteronuclear mixing periods, the C4'i and C4'i-1 coherences are subsequently transferred to, amongst others, H1'i and H1'i-1, respectively, leading to a 2D 1H-31P spectrum which allows a sequential assignment in the 31P-1H1' region of the spectrum, i.e. in the region where the proton resonances overlap least. The experiment is demonstrated on a 13C-labeled RNA hairpin with the sequence 5'(GGGC-CAAA-GCCU)3'. PMID:7533569

  7. Stand-off explosive detection utilizing low power stimulated emission nuclear quadrupole resonance detection and subwavelength focusing wideband super lens

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

    The need for advanced techniques to detect improvised explosive devices (IED) at stand-off distances greater than ten (10) meters has driven AMI Research and Development (AMI) to develop a solution to detect and identify the threat utilizing a forward looking Synthetic Aperture Radar (SAR) combined with our CW radar technology Nuclear Quadrupole Resonance (NQR) detection system. The novel features include a near-field sub-wavelength focusing antenna, a wide band 300 KHz to 300 MHz rapidly scanning CW radar facilitated by a high Q antenna/tuner, and an advanced processor utilizing Rabi transitions where the nucleus oscillates between states under the time dependent incident electromagnetic field and alternately absorbs energy from the incident field while emitting coherent energy via stimulated emission. AMI's Sub-wavelength Focusing Wide Band Super Lens uses a Near-Field SAR, making detection possible at distances greater than ten (10) meters. This super lens is capable of operating on the near-field and focusing electromagnetic waves to resolutions beyond the diffraction limit. When applied to the case of a vehicle approaching an explosive hazard the methodologies of synthetic aperture radar is fused with the array based super resolution and the NQR data processing detecting the explosive hazard.

  8. NEXAFS experiment and multiple scattering calculations on KO2: Effects on the π resonance in the solid phase

    NASA Astrophysics Data System (ADS)

    Pedio, M.; Wu, Z. Y.; Benfatto, M.; Mascaraque, A.; Michel, E.; Ottaviani, C.; Crotti, C.; Peloi, M.; Zacchigna, M.; Comicioli, C.

    2002-10-01

    The high-energy resolution O K-edge absorption near-edge x-ray absorption fine structure spectrum has been measured for in situ prepared potassium superoxide. The experimental data have been analyzed in detail by multiple scattering calculations using self-consistent field potentials. In particular, the so-called π resonance at the rising edge, which presents a double-peak structure, has been totally resolved and reproduced by the calculations. This analysis indicates that the grown material is arranged in a KO2 structure with an O-O distance between 1.31 and 1.34 Å. Moreover, the calculation demonstrates both a complete ionic character of the bound between the O2- anion and K atoms and a strong interaction between the anion and solid-state matrices.

  9. High-frequency ESR measurements and ESR/NMR double resonance experiments of lightly phosphorous-doped silicon

    NASA Astrophysics Data System (ADS)

    Fujii, Y.; Mitsudo, S.; Morimoto, K.; Mizusaki, T.; Gwak, M.; Lee, S. G.; Fukuda, A.; Matsubara, A.; Ueno, T.; Lee, S.

    2014-12-01

    We studied lightly doped Si:P with high-frequency (80-120 GHz) ESR and ESR/NMR double magnetic resonance techniques in the temperature range down to 1.4 K. We found dynamic nuclear polarization of 31P from steady-state ESR measurements with approximately 3.6 T. We derived the nuclear spin relaxation time, T1N, of 31P by analysing the time-evolution of ESR spectra utilizing the dynamic nuclear polarization effect. We derive temperature and magnetic field dependence of T1N and compare with experimental data. Furthermore, from our ESR measurements, we modulate the nuclear polarization of 31P by applying an RF field.

  10. A multi-sample changer coupled to an electron cyclotron resonance source for accelerator mass spectrometry experiments.

    PubMed

    Vondrasek, R; Palchan, T; Pardo, R; Peters, C; Power, M; Scott, R

    2014-02-01

    A new multi-sample changer has been constructed allowing rapid changes between samples. The sample changer has 20 positions and is capable of moving between samples in 1 min. The sample changer is part of a project using Accelerator Mass Spectrometry (AMS) at the Argonne Tandem Linac Accelerator System (ATLAS) facility to measure neutron capture rates on a wide range of actinides in a reactor environment. This project will require the measurement of a large number of samples previously irradiated in the Advanced Test Reactor at Idaho National Laboratory. The AMS technique at ATLAS is based on production of highly charged positive ions in an electron cyclotron resonance ion source followed by acceleration in the ATLAS linac. The sample material is introduced into the plasma via laser ablation chosen to limit the dependency of material feed rates upon the source material composition as well as minimize cross-talk between samples. PMID:24593487

  11. Visualization of Periventricular Collaterals in Moyamoya Disease with Flow-sensitive Black-blood Magnetic Resonance Angiography: Preliminary Experience

    PubMed Central

    FUNAKI, Takeshi; FUSHIMI, Yasutaka; TAKAHASHI, Jun C.; TAKAGI, Yasushi; ARAKI, Yoshio; YOSHIDA, Kazumichi; KIKUCHI, Takayuki; MIYAMOTO, Susumu

    2015-01-01

    Fragile abnormal collaterals in moyamoya disease, known as “moyamoya vessels,” have rarely been defined. While flow-sensitive black-blood magnetic resonance angiography (FSBB-MRA) is a promising technique for visualizing perforating arteries, as of this writing no other reports exist regarding its application to moyamoya disease. Six adults with moyamoya disease underwent FSBB-MRA. It depicted abnormal collaterals as extended lenticulostriate, thalamic perforating, or choroidal arteries, which were all connected to the medullary or insular artery in the periventricular area and supplied the cortex. This preliminary case series illustrates the potential for FSBB-MRA to reveal abnormal moyamoya vessels, which could be reasonably defined as periventricular collaterals. PMID:25739429

  12. Magnetic resonance of the chest: initial experience with imaging and in vivo T1 and T2 calculations

    SciTech Connect

    Ross, J.S.; O'Donovan, P.B.; Novoa, R.; Mehta, A.; Buonocore, E.; MacIntyre, W.J.; Golish, J.A.; Ahmad, M.

    1984-07-01

    Magnetic resonance (MR) imaging of the chest was performed in 33 patients; 28 patients had a variety of malignant tumors and five had benign processes involving the pleura, chest wall, mediastinum, hila, and pulmonary parenchyma. In addition, in vivo T1 and T2 calculations were performed on 17 malignancies and 2 benign processes. Of the 18 patients examined with both MR and computed tomography (CT), 15 MR examinations were considered to be as diagnostic as CT in demonstrating abnormalities. It is concluded that, with current technology without respiratory or cardiac gating, MR offers little improvement in diagnosis over contrast-enhanced CT. Furthermore, it does not appear possible to predict tissue type based on T1 and T2 measurements because of a wide overlap in these values.

  13. Reduced dimensionality tailored HN(C)N experiments for facile backbone resonance assignment of proteins through unambiguous identification of sequential HSQC peaks

    NASA Astrophysics Data System (ADS)

    Kumar, Dinesh

    2013-12-01

    Two novel reduced dimensionality (RD) tailored HN(C)N [S.C. Panchal, N.S. Bhavesh, R.V. Hosur, Improved 3D triple resonance experiments, HNN and HN(C)N, for HN and 15N sequential correlations in (13C, 15N) labeled proteins: application to unfolded proteins, J. Biomol. NMR 20 (2001) 135-147] experiments are proposed to facilitate the backbone resonance assignment of proteins both in terms of its accuracy and speed. These experiments - referred here as (4,3)D-hNCOcaNH and (4,3)D-hNcoCANH - exploit the linear combination of backbone 15N and 13C‧/13Cα chemical shifts simultaneously to achieve higher peak dispersion and randomness along their respective F1 dimensions. Simply, this has been achieved by modulating the backbone 15N(i) chemical shifts with that of 13C‧ (i - 1)/13Cα (i - 1) spins following the established reduced dimensionality NMR approach [T. Szyperski, D.C. Yeh, D.K. Sukumaran, H.N. Moseley, G.T. Montelione, Reduced-dimensionality NMR spectroscopy for high-throughput protein resonance assignment, Proc. Natl. Acad. Sci. USA 99 (2002) 8009-8014]. Though the modification is simple it has resulted an ingenious improvement of HN(C)N both in terms of peak dispersion and easiness of establishing the sequential connectivities. The increased dispersion along F1 dimension solves two purposes here: (i) resolves the ambiguities arising because of degenerate 15N chemical shifts and (ii) reduces the signal overlap in F2(15N)-F3(1H) planes (an important requisite in HN(C)N based assignment protocol for facile and unambiguous identification of sequentially connected HSQC peaks). The performance of both these experiments and the assignment protocol has been demonstrated using bovine apo Calbindin-d9k (75 aa) and urea denatured UNC60B (a 152 amino acid ADF/cofilin family protein of Caenorhabditis elegans), as representatives of folded and unfolded protein systems, respectively.

  14. Towards ferromagnetic quantum criticality in FeGa3 -xGex :71Ga NQR as a zero-field microscopic probe

    NASA Astrophysics Data System (ADS)

    Majumder, M.; Wagner-Reetz, M.; Cardoso-Gil, R.; Gille, P.; Steglich, F.; Grin, Y.; Baenitz, M.

    2016-02-01

    71Ga NQR, magnetization, and specific-heat measurements have been performed on polycrystalline Ge-doped FeGa3 samples. A crossover from an insulator to a correlated local moment metal in the low-doping regime and the evolution of itinerant ferromagnet upon further doping is found. For the nearly critical concentration at the threshold of ferromagnetic order, xC=0.15, 71(1 /T1T ) exhibits a pronounced T-4 /3 power law over two orders of magnitude in temperature, which indicates three-dimensional quantum critical ferromagnetic fluctuations. Furthermore, for the ordered x =0.2 sample (TC≈6 K), 71(1 /T1T ) could be fitted well in the frame of Moriya's self-consistent renormalization theory for weakly ferromagnetic systems with 1 /T1T ˜χ . In contrast to this, the low-doping regime nicely displays local moment behavior where 1 /T1T ˜χ2 is valid. For T →0 , the Sommerfeld ratio γ =(C /T ) is enhanced (70 mJ /mole K2 for x =0.1 ) , which indicates the formation of heavy 3 d electrons.

  15. In vivo (31)P magnetic resonance spectroscopy of the human liver at 7?T: an initial experience.

    PubMed

    Chmelik, Marek; Povaan, Michal; Krk, Martin; Gruber, Stephan; Tka?ov, Martin; Trattnig, Siegfried; Bogner, Wolfgang

    2014-04-01

    Phosphorus ((31) P) MRS is a powerful tool for the non-invasive investigation of human liver metabolism. Four in vivo (31) P localization approaches (single voxel image selected in vivo spectroscopy (3D-ISIS), slab selective 1D-ISIS, 2D chemical shift imaging (CSI), and 3D-CSI) with different voxel volumes and acquisition times were demonstrated in nine healthy volunteers. Localization techniques provided comparable signal-to-noise ratios normalized for voxel volume and acquisition time differences, Cramer-Rao lower bounds (8.7??3.3%1D-ISIS , 7.6??2.5%3D-ISIS , 8.6??4.2%2D-CSI , 10.3??2.7%3D-CSI ), and linewidths (50??24 Hz1D-ISIS , 34??10 Hz3D-ISIS , 33??10 Hz2D-CSI , 34??11 Hz3D-CSI ). Longitudinal (T1 ) relaxation times of human liver metabolites at 7?T were assessed by 1D-ISIS inversion recovery in the same volunteers (n?=?9). T1 relaxation times of hepatic (31) P metabolites at 7?T were the following: phosphorylethanolamine - 4.41??1.55?s; phosphorylcholine - 3.74??1.31?s; inorganic phosphate - 0.70??0.33?s; glycerol 3-phosphorylethanolamine - 6.19??0.91?s; glycerol 3-phosphorylcholine - 5.94??0.73?s; ?-adenosine triphosphate (ATP) - 0.50??0.08?s; ?-ATP - 0.46??0.07?s; ?-ATP - 0.56??0.07?s. The improved spectral resolution at 7?T enabled separation of resonances in the phosphomonoester and phosphodiester spectral region as well as nicotinamide adenine dinucleotide and uridine diphosphoglucose signals. An additional resonance at 2.06?ppm previously assigned to phosphoenolpyruvate or phosphatidylcholine is also detectable. These are the first (31) P metabolite relaxation time measurements at 7?T in human liver, and they will help in the exploration of new, exciting questions in metabolic research with 7?T MR. PMID:24615903

  16. Simulation of non-resonant internal kink mode with toroidal rotation in the National Spherical Torus Experiment

    SciTech Connect

    Wang, Feng; Liu, J. Y.; Fu, G. Y.; Breslau, J. A.; Tritz, Kevin

    2013-07-15

    Plasmas in spherical and conventional tokamaks, with weakly reversed shear q profile and minimum q above but close to unity, are susceptible to an non-resonant (m,n) = (1,1) internal kink mode. This mode can saturate and persist and can induce a (2,1) seed island for Neoclassical Tearing Mode. [Breslau et al. Nucl. Fusion 51, 063027 (2011)]. The mode can also lead to large energetic particle transport and significant broadening of beam-driven current. Motivated by these important effects, we have carried out extensive nonlinear simulations of the mode with finite toroidal rotation using parameters and profiles of an NTSX plasma with a weakly reversed shear profile. The numerical results show that, at the experimental level, plasma rotation has little effect on either equilibrium or linear stability. However, rotation can significantly influence the nonlinear dynamics of the (1,1) mode and the induced (2,1) magnetic island. The simulation results show that a rotating helical equilibrium is formed and maintained in the nonlinear phase at finite plasma rotation. In contrast, for non-rotating cases, the nonlinear evolution exhibits dynamic oscillations between a quasi-2D state and a helical state. Furthermore, the effects of rotation are found to greatly suppress the (2,1) magnetic island even at a low level.

  17. Tracking molecular resonance forms of donor-acceptor push-pull molecules by single-molecule conductance experiments.

    PubMed

    Lissau, Henriette; Frisenda, Riccardo; Olsen, Stine T; Jevric, Martyn; Parker, Christian R; Kadziola, Anders; Hansen, Thorsten; van der Zant, Herre S J; Brøndsted Nielsen, Mogens; Mikkelsen, Kurt V

    2015-01-01

    The ability of molecules to change colour on account of changes in solvent polarity is known as solvatochromism and used spectroscopically to characterize charge-transfer transitions in donor-acceptor molecules. Here we report that donor-acceptor-substituted molecular wires also exhibit distinct properties in single-molecule electronics under the influence of a bias voltage, but in absence of solvent. Two oligo(phenyleneethynylene) wires with donor-acceptor substitution on the central ring (cruciform-like) exhibit remarkably broad conductance peaks measured by the mechanically controlled break-junction technique with gold contacts, in contrast to the sharp peak of simpler molecules. From a theoretical analysis, we explain this by different degrees of charge delocalization and hence cross-conjugation at the central ring. Thus, small variations in the local environment promote the quinoid resonance form (off), the linearly conjugated (on) or any form in between. This shows how the conductance of donor-acceptor cruciforms is tuned by small changes in the environment. PMID:26667583

  18. The design of double electrostatic-lens optics for resonance enhanced multiphoton ionization and photoelectron imaging experiments

    SciTech Connect

    Qu, Zehua; Li, Chunsheng; Qin, Zhengbo E-mail: xfzheng@mail.ahnu.edu.cn; Zheng, Xianfeng E-mail: xfzheng@mail.ahnu.edu.cn; Yao, Guanxin; Zhang, Xianyi; Cui, Zhifeng

    2015-06-15

    Compared to single ion/electron-optics for velocity-map imaging, a double-focusing lens assembly designed not only allows for mapping velocity imaging of photoelectrons but also allows for investigating the vibrational structure of the intermediate states of neutral species in resonance enhanced multiphoton ionization (REMPI) spectra. In this presentation, in order to record REMPI and photoelectron spectra separately, we have constructed a compact photoelectron velocity-map imaging (VMI) apparatus combined with an opposite linear Wiley-Mclaren time-of-flight mass spectrometer (TOFMS). A mass resolution (m/Δm) of ∼1300 for TOFMS and electron energy resolution (ΔE/E) of 2.4% for VMI have been achieved upon three-photon ionization of Xe atom at 258.00 nm laser wavelength. As a benchmark, in combination of one-color (1 + 1) REMPI and photoelectron imaging of benzene via 6{sup 1} and 6{sup 1}1{sup 1} vibronic levels in the S{sub 1} state, the vibrational structures of the cation and photoelectron angular anisotropy are unraveled. In addition, two-color (1 + 1′) REMPI and photoelectron imaging of aniline was used to complete the accurate measurement of ionization potential (62 271 ± 3 cm{sup −1}). The results suggest that the apparatus is a powerful tool for studying photoionization dynamics in the photoelectron imaging using vibrational-state selected excitation to the intermediate states of neutrals based on REMPI technique.

  19. Simulation of non-resonant internal kink mode with toroidal rotation in the National Spherical Torus Experiment

    NASA Astrophysics Data System (ADS)

    Wang, Feng; Fu, G. Y.; Breslau, J. A.; Tritz, Kevin; Liu, J. Y.

    2013-07-01

    Plasmas in spherical and conventional tokamaks, with weakly reversed shear q profile and minimum q above but close to unity, are susceptible to an non-resonant (m,n) = (1,1) internal kink mode. This mode can saturate and persist and can induce a (2,1) seed island for Neoclassical Tearing Mode. [Breslau et al. Nucl. Fusion 51, 063027 (2011)]. The mode can also lead to large energetic particle transport and significant broadening of beam-driven current. Motivated by these important effects, we have carried out extensive nonlinear simulations of the mode with finite toroidal rotation using parameters and profiles of an NTSX plasma with a weakly reversed shear profile. The numerical results show that, at the experimental level, plasma rotation has little effect on either equilibrium or linear stability. However, rotation can significantly influence the nonlinear dynamics of the (1,1) mode and the induced (2,1) magnetic island. The simulation results show that a rotating helical equilibrium is formed and maintained in the nonlinear phase at finite plasma rotation. In contrast, for non-rotating cases, the nonlinear evolution exhibits dynamic oscillations between a quasi-2D state and a helical state. Furthermore, the effects of rotation are found to greatly suppress the (2,1) magnetic island even at a low level.

  20. The design of double electrostatic-lens optics for resonance enhanced multiphoton ionization and photoelectron imaging experiments

    NASA Astrophysics Data System (ADS)

    Qu, Zehua; Li, Chunsheng; Qin, Zhengbo; Zheng, Xianfeng; Yao, Guanxin; Zhang, Xianyi; Cui, Zhifeng

    2015-06-01

    Compared to single ion/electron-optics for velocity-map imaging, a double-focusing lens assembly designed not only allows for mapping velocity imaging of photoelectrons but also allows for investigating the vibrational structure of the intermediate states of neutral species in resonance enhanced multiphoton ionization (REMPI) spectra. In this presentation, in order to record REMPI and photoelectron spectra separately, we have constructed a compact photoelectron velocity-map imaging (VMI) apparatus combined with an opposite linear Wiley-Mclaren time-of-flight mass spectrometer (TOFMS). A mass resolution (m/Δm) of ˜1300 for TOFMS and electron energy resolution (ΔE/E) of 2.4% for VMI have been achieved upon three-photon ionization of Xe atom at 258.00 nm laser wavelength. As a benchmark, in combination of one-color (1 + 1) REMPI and photoelectron imaging of benzene via 61 and 6111 vibronic levels in the S1 state, the vibrational structures of the cation and photoelectron angular anisotropy are unraveled. In addition, two-color (1 + 1') REMPI and photoelectron imaging of aniline was used to complete the accurate measurement of ionization potential (62 271 ± 3 cm-1). The results suggest that the apparatus is a powerful tool for studying photoionization dynamics in the photoelectron imaging using vibrational-state selected excitation to the intermediate states of neutrals based on REMPI technique.

  1. Operational experience with the Argonne National Laboratory Californium Rare Ion Breeder Upgrade facility and electron cyclotron resonance charge breeder

    NASA Astrophysics Data System (ADS)

    Vondrasek, R.; Clark, J.; Levand, A.; Palchan, T.; Pardo, R.; Savard, G.; Scott, R.

    2014-02-01

    The Californium Rare Ion Breeder Upgrade (CARIBU) of the Argonne National Laboratory Argonne Tandem Linac Accelerator System (ATLAS) facility provides low-energy and accelerated neutron-rich radioactive beams to address key nuclear physics and astrophysics questions. A 350 mCi 252Cf source produces fission fragments which are thermalized and collected by a helium gas catcher into a low-energy particle beam with a charge of 1+ or 2+. An electron cyclotron resonance (ECR) ion source functions as a charge breeder in order to raise the ion charge sufficiently for acceleration in the ATLAS linac. The ECR charge breeder has achieved stable beam charge breeding efficiencies of 10.1% for 23Na7+, 17.9% for 39K10+, 15.6% for 84Kr17+, and 12.4% for 133Cs27+. For the radioactive beams, a charge breeding efficiency of 11.7% has been achieved for 143Cs27+ and 14.7% for 143Ba27+. The typical breeding times are 10 ms/charge state, but the source can be tuned such that this value increases to 100 ms/charge state with the best breeding efficiency corresponding to the longest breeding times—the variation of efficiencies with breeding time will be discussed. Efforts have been made to characterize and reduce the background contaminants present in the ion beam through judicious choice of q/m combinations. Methods of background reduction are being investigated based upon plasma chamber cleaning and vacuum practices.

  2. Tracking molecular resonance forms of donor–acceptor push–pull molecules by single-molecule conductance experiments

    PubMed Central

    Lissau, Henriette; Frisenda, Riccardo; Olsen, Stine T.; Jevric, Martyn; Parker, Christian R.; Kadziola, Anders; Hansen, Thorsten; van der Zant, Herre S. J.; Brøndsted Nielsen, Mogens; Mikkelsen, Kurt V.

    2015-01-01

    The ability of molecules to change colour on account of changes in solvent polarity is known as solvatochromism and used spectroscopically to characterize charge-transfer transitions in donor–acceptor molecules. Here we report that donor–acceptor-substituted molecular wires also exhibit distinct properties in single-molecule electronics under the influence of a bias voltage, but in absence of solvent. Two oligo(phenyleneethynylene) wires with donor–acceptor substitution on the central ring (cruciform-like) exhibit remarkably broad conductance peaks measured by the mechanically controlled break-junction technique with gold contacts, in contrast to the sharp peak of simpler molecules. From a theoretical analysis, we explain this by different degrees of charge delocalization and hence cross-conjugation at the central ring. Thus, small variations in the local environment promote the quinoid resonance form (off), the linearly conjugated (on) or any form in between. This shows how the conductance of donor–acceptor cruciforms is tuned by small changes in the environment. PMID:26667583

  3. Hybridization-driven gap in U3Bi4Ni3: a 209Bi NMR/NQR study

    SciTech Connect

    Baek, Seung H

    2009-01-01

    We report {sup 209}Bi nuclear-magnetic-resonance and nuclear-quadrupole-resonance measurements on a single crystal of the Kondo insulator U{sub 3}Bi{sub 4}Ni{sub 3}. The {sup 209}Bi nuclear-spin-lattice relaxation rate (T{sub 1}{sup -1}) shows activated behavior and is well fit by a spin gap of 220 K. The {sup 209}Bi Knight shift (K) exhibits a strong temperature dependence arising from 5f electrons, in which K is negative at high temperatures and increases as the temperature is lowered. Below 50 K, K shows a broad maximum and decreases slightly upon further cooling. Our data provide insight into the evolution of the hyperfine fields in a fully gapped Kondo insulator based on 5f electron hybridization.

  4. Gyrotron anode modulation of the Electron Cyclotron Resonant Heating (ECRH) from dc to 50 kHz on the Tandem Mirror Experiment-Upgrade (TMX-U)

    SciTech Connect

    Williams, C.W.; Heefner, J.W.; Rupert, R.R.

    1985-11-11

    This paper describes control of gyrotron microwave energy output by modulation of gyrotron anode voltage. At present, Electron Cyclotron Resonant Heating (ECRH) uses five gyrotrons on the Tandem Mirror Experiment-Upgrade (TMX-U) for plasma heating. One is in the 10 kG region of each end plug, one at the 5 kG region of each end plug, and one is used for central-cell heating. Also described are the design and operation of the anode modulation system. The operating advantages of gyrotron anode modulation include power balance, independent control of each gyrotron, an ability to modulate microwave output power up to 50 kHz, and gyrotron tuning. The performance results of anode modulation will be discussed. 9 figs.

  5. Microwave measurement test results of circular waveguide components for electron cyclotron resonant heating (ECRH) of the Tandem Mirror Experiment-Upgrade (TMX-U)

    SciTech Connect

    Williams, C.W.; Rubert, R.R.; Coffield, F.E.; Felker, B.; Stallard, B.W.; Taska, J.

    1983-12-01

    Development of high-power components for electron cyclotron resonant heating (ECRH) applications requires extensive testing. In this paper we describe the high-power testing of various circular waveguide components designed for application on the Tandem Mirror Experiment-Upgrade (TMX-U). These include a 2.5-in. vacuum valve, polarizing reflectors, directional couplers, mode converters, and flexible waveguides. All of these components were tested to 200 kW power level with 40-ms pulses. Cold tests were used to determine field distribution. The techniques used in these tests are illustrated. The new high-power test facility at Lawrence Livermore National Laboratory (LLNL) is described and test procedures are discussed. We discuss the following test results: efficiency at high power of mode converters, comparison of high power vs low power for waveguide components, and full power tests of the waveguide system. We also explain the reasons behind selection of these systems for use on TMX-U.

  6. Bonding and molecular motions in the 1:1 molecular complexes of 1,4-diazabicyclo[2.2.2]octane with tetrahalomethane as studied by means of NQR

    NASA Astrophysics Data System (ADS)

    Okuda, T.; Suzuki, T.; Negita, H.

    1983-12-01

    NQR spectra were observed in the complexes of 1,4-diazabicyclo[2.2.2]octane (DABCO) with tetrachloromethane and tetrabromomethane at various temperatures. A phase transition was found at 319 K for DABCO·CBr 4. From spin-lattice relaxation times of nitrogen-14 in DABCO·CBr 4, the activation energy of the reorientation of DABCO about the NN axis was calculated to be 18.3 kJ/mol which agrees with the value obtained from the second moment of proton NMR spectra. The bond nature is discussed using the Townes-Dailey treatment.

  7. The value of magnetic resonance imaging in the early diagnosis of Creutzfeldt-Jakob disease – own experience

    PubMed Central

    Bekiesińska-Figatowska, Monika; Kuczyńska-Zardzewiały, Arleta; Pomianowska, Barbara; Kajdana, Katarzyna; Szpak, Grażyna M.; Iwanowska, Beata; Mądzik, Jarosław

    2012-01-01

    Summary Background: Creutzfeldt-Jakob disease (CJD) is a rare progressive neurodegenerative disorder, caused by the deposition of the pathological isoform of prion protein PrPsc in the central nervous system. The classic triad of symptoms consists of: rapidly progressive dementia, myoclonus and typical electroencephalographic findings (intermittent rhythmic delta activity and periodic sharp wave complexes). Detection of 14-3-3 protein in the cerebrospinal fluid plays an important diagnostic role as well. Magnetic resonance (MR) images of the brain have been recently incorporated into the diagnostic criteria of sporadic Creutzfeldt-Jakob disease. Case Report: MR examinations were performed in a 65-year-old man and a 54-year-old woman with delusional disorder and cognitive dysfunction, respectively. Diffusion restriction (hyperintense signal in DWI) was shown in the cortex of the left parietal and occipital lobe in the first patient and symmetrically in the cortex of both cerebral hemispheres except for precentral gyri in the second one. In both cases, the first examinations were misread, with the suspicion of ischemic infarcts as the first differential diagnosis. Consultations and subsequent MR examinations in which lesions in subcortical nuclei appeared allowed for a diagnosis of probable CJD. In the first case it was confirmed by clinical picture, EEG and finally – autopsy. In the second case, EEG was not typical for CJD but the clinical course of the disease confirmed that diagnosis. Conclusions: The authors present the cases of two patients with characteristic MR images that allowed early diagnosis of probable Creutzfeldt-Jakob disease before the characteristic clinical picture appeared. Early diagnosis is nowadays important for the prevention of disease transmission and in the future – hopefully – for early treatment. PMID:22802869

  8. Comparing hepatic 2D and 3D magnetic resonance elastography methods in a clinical setting – Initial experiences

    PubMed Central

    Forsgren, Mikael F.; Norén, Bengt; Kihlberg, Johan; Dahlqvist Leinhard, Olof; Kechagias, Stergios; Lundberg, Peter

    2015-01-01

    Purpose Continuous monitoring of liver fibrosis progression in patients is not feasible with the current diagnostic golden standard (needle biopsy). Recently, magnetic resonance elastography (MRE) has emerged as a promising method for such continuous monitoring. Since there are different MRE methods that could be used in a clinical setting there is a need to investigate whether measurements produced by these MRE methods are comparable. Hence, the purpose of this pilot study was to evaluate whether the measurements of the viscoelastic properties produced by 2D (stiffness) and 3D (elasticity and ‘Gabs,Elastic’) MRE are comparable. Materials and methods Seven patients with diffuse or suspect diffuse liver disease were examined in the same day with the two MRE methods. 2D MRE was performed using an acoustic passive transducer, with a 1.5 T GE 450 W MR system. 3D MRE was performed using an electromagnetic active transducer, with a 1.5 T Philips Achieva MR system. Finally, mean viscoelastic values were extracted from the same anatomical region for both methods by an experienced radiologist. Results Stiffness correlated well with the elasticity, R2 = 0.96 (P < 0.001; slope = 1.08, intercept = 0.61 kPa), as well as with ‘Gabs,Elastic’ R2 = 0.96 (P < 0.001; slope = 0.95, intercept = 0.28 kPa). Conclusion This pilot study shows that different MRE methods can produce comparable measurements of the viscoelastic properties of the liver. The existence of such comparable measurements is important, both from a clinical as well as a research perspective, since it allows for equipment-independent monitoring of disease progression. PMID:26937438

  9. Adapting Data Processing To Compare Model and Experiment Accurately: A Discrete Element Model and Magnetic Resonance Measurements of a 3D Cylindrical Fluidized Bed

    PubMed Central

    2013-01-01

    Discrete element modeling is being used increasingly to simulate flow in fluidized beds. These models require complex measurement techniques to provide validation for the approximations inherent in the model. This paper introduces the idea of modeling the experiment to ensure that the validation is accurate. Specifically, a 3D, cylindrical gas-fluidized bed was simulated using a discrete element model (DEM) for particle motion coupled with computational fluid dynamics (CFD) to describe the flow of gas. The results for time-averaged, axial velocity during bubbling fluidization were compared with those from magnetic resonance (MR) experiments made on the bed. The DEM-CFD data were postprocessed with various methods to produce time-averaged velocity maps for comparison with the MR results, including a method which closely matched the pulse sequence and data processing procedure used in the MR experiments. The DEM-CFD results processed with the MR-type time-averaging closely matched experimental MR results, validating the DEM-CFD model. Analysis of different averaging procedures confirmed that MR time-averages of dynamic systems correspond to particle-weighted averaging, rather than frame-weighted averaging, and also demonstrated that the use of Gaussian slices in MR imaging of dynamic systems is valid. PMID:24478537

  10. Adapting Data Processing To Compare Model and Experiment Accurately: A Discrete Element Model and Magnetic Resonance Measurements of a 3D Cylindrical Fluidized Bed.

    PubMed

    Boyce, Christopher M; Holland, Daniel J; Scott, Stuart A; Dennis, John S

    2013-12-18

    Discrete element modeling is being used increasingly to simulate flow in fluidized beds. These models require complex measurement techniques to provide validation for the approximations inherent in the model. This paper introduces the idea of modeling the experiment to ensure that the validation is accurate. Specifically, a 3D, cylindrical gas-fluidized bed was simulated using a discrete element model (DEM) for particle motion coupled with computational fluid dynamics (CFD) to describe the flow of gas. The results for time-averaged, axial velocity during bubbling fluidization were compared with those from magnetic resonance (MR) experiments made on the bed. The DEM-CFD data were postprocessed with various methods to produce time-averaged velocity maps for comparison with the MR results, including a method which closely matched the pulse sequence and data processing procedure used in the MR experiments. The DEM-CFD results processed with the MR-type time-averaging closely matched experimental MR results, validating the DEM-CFD model. Analysis of different averaging procedures confirmed that MR time-averages of dynamic systems correspond to particle-weighted averaging, rather than frame-weighted averaging, and also demonstrated that the use of Gaussian slices in MR imaging of dynamic systems is valid. PMID:24478537

  11. Signature of the seasonal migration of global lightning in the variation of Schumann resonance peak frequencies - Theory versus experiment

    NASA Astrophysics Data System (ADS)

    Sátori, Gabriella; Mushtak, Vadim; Williams, Earle; Nagy, Tamás.

    2010-05-01

    The distance between the active lightning sources and a fixed receiver changes when the global lightning migrates northward/southward over the year. Schumann resonance (SR) peak frequencies depend on both the source-observer geometry and the propagation conditions in the Earth-ionosphere cavity. The source-observer geometry can be manifest in frequency variations with different signs for the different modes and field components. This distance- dependent frequency variation is demonstrated in SR frequency observations at Nagycenk, Hungary. The position of the lightning centroids is documented with respect to the observer in the longitudinal range of the three tropical chimney regions for each month on the basis of the OTD/LIS satellite observations. Simulation of the distance-dependent frequency variation is based on the computation of the spectra of the vertical electric, north-south, and east-west magnetic field components, via the Two-Dimensional Telegraph Equation (TDTE) technique (Kirillov, 2002) for each chimney region in its diurnal phase of greatest activity, and with each (Maritime Continent, Africa, America) having well established spatial-temporal dynamics. Modal peak frequencies are being obtained, along with modal intensities and quality factors, by means of the least-squares fitting of "experimental" spectra by the "classic" Lorentzian functional (Williams et al., 2006). For each chimney region, numerous scenarios have been simulated; to consider the first and second Lorentzian-modes, a five-mode (N=5) Lorentzian procedure has been exploited. The largest frequency response (maximum in Northern hemisphere summer, minimum in winter) for the seasonal migration can be observed in the case of the 1st Ez mode when it is dominated by the Maritime Continent (7-10 UT). According to the simulation, this maximal response is attributed to the source proximity to the nodal region at about 10 Mm distance, where the frequency exhibits singular behavior. In the case of Africa, the frequency varies little during the seasonal migration and has opposite sign: lower in Northern Hemisphere summer than winter. The frequency has only minor fluctuation in the case of the American source due to the seasonal migration path being roughly perpendicular to the source-receiver great circle. The 1st magnetic mode has increasing frequency at Nagycenk with increasing source distance in accordance with the theoretical description. These general methods are suitable to identify global redistribution of global lightning due to climate change.

  12. The use of election paramagnetic resonance spectroscopy in early preformulation experiments: the impact of different experimental formulations on the release of a lipophilic spin probe into gastric juice.

    PubMed

    Bittner, B; Isel, H; Mountfield, R J

    2001-03-01

    The lipophilic spin probe TEMPOL-benzoate was dissolved in different experimental formulations, including polyethylene glycol 400 (PEG 400), Miglyol, glycerol monooleate (GMO), and Cremophor RH-40. Samples were measured by electron paramagnetic resonance (EPR) spectroscopy before and after addition to human gastric juice. The distance between the first and the third peak in the EPR spectrum (2a(N)) was measured to monitor the polarity of the spin probe's microenvironment. Moreover, the ratio between the signal amplitudes of the second and the third peak (a/b ratio) was used to monitor the mobility of the spin probe in a certain formulation. Thus, by calculating 2a(N) and the a/b ratio of the EPR spectra it was possible to determine a potential release of the spin probe from different formulations into gastric juice. It was found that oily and surface-active vehicles (Miglyol, Cremophor RH-40, and GMO) were more suitable to protect a lipophilic compound from being released within a gastric environment than PEG 400. Our results demonstrate that EPR spectroscopy seems to be a promising tool in early preformulation experiments to monitor the release of spin probes from formulations of different nature. This kind of experiment can be of value for the optimization of exploratory formulations. PMID:11226824

  13. 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, Laouès; Aissani, Sarra; Marêché, 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

  14. Zero-field splittings of NQR spectra for bismuth(III) oxy compounds revealed by quadrupole spin echo envelopes

    NASA Astrophysics Data System (ADS)

    Kravchenko, E. A.; Orlov, V. G.; Morgunov, V. G.; Shlykov, M. P.

    2007-11-01

    Local magnetic fields up to 250 G were earlier found by measuring the NQI parameters in bismuth(III) oxy compounds conventionally considered as diamagnets, a strong increase in the 209Bi line intensities being observed in external magnetic fields. An approach based on registration of the quadrupole spin-echo envelopes enabled to reveal small (within an inhomogeneous line broadening) splittings in some other compounds of this type. The modeling of time dependence of the quadrupole spin echo amplitude indicated that modulations of the spin echo envelope in BaBiO2Cl and Bi3B5O12 resulted from weak (?5 G) local magnetic fields. By using this approach, it was found that an increase in the 209Bi resonance intensity in external magnetic fields is related to an influence of the fields on the nuclear spin-spin relaxation rate for the appropriate compounds.

  15. Zero-field splittings of NQR spectra for bismuth(III) oxy compounds revealed by quadrupole spin echo envelopes

    NASA Astrophysics Data System (ADS)

    Kravchenko, E. A.; Orlov, V. G.; Morgunov, V. G.; Shlykov, M. P.

    Local magnetic fields up to 250 G were earlier found by measuring the NQI parameters in bismuth(III) oxy compounds conventionally considered as diamagnets, a strong increase in the 209Bi line intensities being observed in external magnetic fields. An approach based on registration of the quadrupole spin-echo envelopes enabled to reveal small (within an inhomogeneous line broadening) splittings in some other compounds of this type. The modeling of time dependence of the quadrupole spin echo amplitude indicated that modulations of the spin echo envelope in BaBi02Cl and Bi3B5012 resulted from weak (?5 G) local magnetic fields. By using this approach, it was found that an increase in the 209Bi resonance intensity in external magnetic fields is related to an influence of the fields on the nuclear spin-spin relaxation rate for the appropriate compounds.

  16. 75As-NQR/NMR Studies on Oxygen-Deficient Iron-Based Oxypnictide Superconductors LaFeAsO1-y ( y = 0, 0.25, 0.4) and NdFeAsO0.6

    NASA Astrophysics Data System (ADS)

    Mukuda, Hidekazu; Terasaki, Nobuyuki; Kinouchi, Hiroaki; Yashima, Mitsuharu; Kitaoka, Yoshio; Suzuki, Shinnosuke; Miyasaka, Shigeki; Tajima, Setsuko; Miyazawa, Kiichi; Shirage, Parasharam; Kito, Hijiri; Eisaki, Hiroshi; Iyo, Akira

    2008-09-01

    We report 75As-NQR/NMR studies on the oxygen-deficient iron (Fe)-based oxypnictide superconductors LaFeAsO0.6 (Tc = 28 K) along with the results on LaFeAsO, LaFeAsO0.75 (Tc = 20 K), and NdFeAsO0.6 (Tc = 53 K). Nuclear spin-lattice relaxation rate 1/T1 of 75As-NQR at zero field on LaFeAsO0.6 has revealed a T3 dependence below Tc upon cooling without the coherence peak just below Tc, evidencing the unconventional superconducting state with the line-node gap. We have found an intimate relationship between the nuclear quadrupole frequency νQ of 75As and Tc for four samples used in this study. It implies microscopically that the local configuration of Fe and As atoms is significantly related to the Tc of the Fe-oxypnictide superconductors, namely, the Tc can be enhanced up to 50 K when the local configuration of Fe and As atoms is optimal, in which the band structure may be also optimized through the variation of hybridization between As 4 p orbitals and Fe 3d orbitals.

  17. An instrument for fast acquisition of fluorescence decay curves at picosecond resolution designed for ``double kinetics'' experiments: Application to fluorescence resonance excitation energy transfer study of protein folding

    NASA Astrophysics Data System (ADS)

    Ishay, Eldad Ben; Hazan, Gershon; Rahamim, Gil; Amir, Dan; Haas, Elisha

    2012-08-01

    The information obtained by studying fluorescence decay of labeled biopolymers is a major resource for understanding the dynamics of their conformations and interactions. The lifetime of the excited states of probes attached to macromolecules is in the nanosecond time regime, and hence, a series of snapshot decay curves of such probes might - in principle - yield details of fast changes of ensembles of labeled molecules down to sub-microsecond time resolution. Hence, a major current challenge is the development of instruments for the low noise detection of fluorescence decay curves within the shortest possible time intervals. Here, we report the development of an instrument, picosecond double kinetics apparatus, that enables recording of multiple fluorescence decay curves with picosecond excitation pulses over wide spectral range during microsecond data collection for each curve. The design is based on recording and averaging multiphoton pulses of fluorescence decay using a fast 13 GHz oscilloscope during microsecond time intervals at selected time points over the course of a chemical reaction or conformational transition. We tested this instrument in a double kinetics experiment using reference probes (N-acetyl-tryptophanamide). Very low stochastic noise level was attained, and reliable multi-parameter analysis such as derivation of distance distributions from time resolved FRET (fluorescence resonance excitation energy transfer) measurements was achieved. The advantage of the pulse recording and averaging approach used here relative to double kinetics methods based on the established time correlated single photon counting method, is that in the pulse recording approach, averaging of substantially fewer kinetic experiments is sufficient for obtaining the data. This results in a major reduction in the consumption of labeled samples, which in many cases, enables the performance of important experiments that were not previously feasible.

  18. Mixed-radiation-field dosimetry utilizing Nuclear Quadrupole Resonance

    SciTech Connect

    Hintenlang, D.E.; Jamil, K.; Iselin, L.H.

    1992-01-01

    Radiation effects on urea, thiourea, guanidine carbonate and guanine sulfate were evaluated for both photon and neutron irradiations. Hydration of these materials typically provides a greatly increased sensitivity to both forms of radiation exposure, although not all materials lend themselves to this treatment without changing the chemical structure of the compound. Urea was found to be the most stable hydrated compound and provides the best sensitivity for quantifying radiation effects using NQR techniques. Urea permits a straight-forward quantification of each of the important parameters of the observed NQR signal, the FID. Several advanced data analysis methods were developed to assist in quantifying NQR spectra, both from urea and materials having more complex molecular structures, such as thiourea and guanidine sulfate. Unfortunately, these analysis techniques are frequently quite time consuming for the complex NQR spectra that result from some of these materials. The simpler analysis afforded by urea has therefore made it the prime candidate for an NQR dosimetry material. The moderate sensitivity of hydrated urea to photon irradiation does not permit this material to achieve the levels of performance required for a personnel dosimeter. It does, however, demonstrate acceptable sensitivity over dose ranges where it could provide a good biological dosimeter for several areas of radiation processing. The demonstrated photon sensitivity could permit hydrated urea to be used in applications such as food irradiation dosimetry. This material also exhibits a good sensitivity to neutron irradiation. The precise correlation between neutron exposure and the parameters of the resulting NQR spectra are currently being developed.

  19. Ferromagnetic resonance in a single crystal of iron borate and magnetic field tuning of hybrid oscillations in a composite structure with a dielectric: Experiment and theory

    NASA Astrophysics Data System (ADS)

    Popov, M. A.; Zavislyak, I. V.; Chumak, H. L.; Strugatsky, M. B.; Yagupov, S. V.; Srinivasan, G.

    2015-07-01

    The high-frequency properties of a composite resonator comprised single crystal iron borate (FeBO3), a canted antiferromagnet with a weak ferromagnetic moment, and a polycrystalline dielectric were investigated at 9-10 GHz. Ferromagnetic resonance in this frequency range was observed in FeBO3 for bias magnetic fields of ˜250 Oe. In the composite resonator, the magnetic mode in iron borate and dielectric mode are found to hybridize strongly. It is shown that the hybrid mode can be tuned with a static magnetic field. Our studies indicate that coupling between the magnetic mode and the dielectric resonance can be altered from maximum hybridization to a minimum by adjusting the position of resonator inside the waveguide. Magnetic field tuning of the resonance frequency by a maximum of 145 MHz and a change in the transmitted microwave power by as much as 16 dB have been observed for a bias field of 250 Oe. A model is discussed for the magnetic field tuning of the composite resonator and theoretical estimates are in reasonable agreement with the data. The composite resonator with a weak ferromagnet and a dielectric is of interest for application in frequency agile devices with electronically tunable electrodynamic characteristics for the mm and sub-mm wave bands.

  20. Feshbach resonances in ultracold gases

    SciTech Connect

    Chin Cheng; Grimm, Rudolf; Julienne, Paul; Tiesinga, Eite

    2010-04-15

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

  1. In vivo semi-automatic segmentation of multicontrast cardiovascular magnetic resonance for prospective cohort studies on plaque tissue composition: initial experience.

    PubMed

    Yoneyama, Taku; Sun, Jie; Hippe, Daniel S; Balu, Niranjan; Xu, Dongxiang; Kerwin, William S; Hatsukami, Thomas S; Yuan, Chun

    2016-01-01

    Automatic in vivo segmentation of multicontrast (multisequence) carotid magnetic resonance for plaque composition has been proposed as a substitute for manual review to save time and reduce inter-reader variability in large-scale or multicenter studies. Using serial images from a prospective longitudinal study, we sought to compare a semi-automatic approach versus expert human reading in analyzing carotid atherosclerosis progression. Baseline and 6-month follow-up multicontrast carotid images from 59 asymptomatic subjects with 16-79 % carotid stenosis were reviewed by both trained radiologists with 2-4 years of specialized experience in carotid plaque characterization with MRI and a previously reported automatic atherosclerotic plaque segmentation algorithm, referred to as morphology-enhanced probabilistic plaque segmentation (MEPPS). Agreement on measurements from individual time points, as well as on compositional changes, was assessed using the intraclass correlation coefficient (ICC). There was good agreement between manual and MEPPS reviews on individual time points for calcification (CA) (area: ICC; 0.85-0.91; volume: ICC; 0.92-0.95) and lipid-rich necrotic core (LRNC) (area: ICC; 0.78-0.82; volume: ICC; 0.84-0.86). For compositional changes, agreement was good for CA volume change (ICC; 0.78) and moderate for LRNC volume change (ICC; 0.49). Factors associated with LRNC progression as detected by MEPPS review included intraplaque hemorrhage (positive association) and reduction in low-density lipoprotein cholesterol (negative association), which were consistent with previous findings from manual review. Automatic classifier for plaque composition produced results similar to expert manual review in a prospective serial MRI study of carotid atherosclerosis progression. Such automatic classification tools may be beneficial in large-scale multicenter studies by reducing image analysis time and avoiding bias between human reviewers. PMID:26169389

  2. 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.

  3. Resonance scraping

    SciTech Connect

    Collins, T.

    1986-06-01

    Protons lost in a ring leave at a few preferred locations, determined by some non-linear property of the dipoles. This paper suggests taking control of lost protons by beating the magnets at their own game - by means of a designed resonance used as a beam scraper. It is a study of suitable resonances, including estimates of the required multipole element strengths. The appropriate resonances are two-dimensional. A large number of figures is included.

  4. Improving Resolution in Fast Rotating-Frame Experiments

    NASA Astrophysics Data System (ADS)

    Casanova, F.; Robert, H.; Pusiol, D.

    2001-07-01

    The rapid rotating-frame technique allows significant reduction in data-acquisition time compared with the two-dimensional method by stroboscopic observation of the nuclear magnetization during its evolution in the rotating frame. A onefold reduction in the dimensionality of the original rotating-frame experiment is achieved by using a train of strong radiofrequency pulses separated by short acquisition windows. The penalty for shortening experimental time is a reduction in spectral resolution compared with the two-dimensional method due to relaxation of transverse magnetization components during the observation windows. A variant of the rapid-rotating frame technique for improving spectral resolution based on undersampling and self-phase encoding is presented. An M-fold resolution improvement requires M experiments, thus, making possible a tradeoff between spectral resolution and experimental time. The technique was applied for spatial localization of quadrupole nuclei in powder solids, and resolution improvement is demonstrated on one- and two-dimensional NQR images.

  5. Resonance Pacemakers in Excitable Media

    NASA Astrophysics Data System (ADS)

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

    2006-06-01

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

  6. 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.

  7. Dynamic coupling of plasmonic resonators

    PubMed Central

    Lee, Suyeon; Park, Q-Han

    2016-01-01

    We clarify the nature of dynamic coupling in plasmonic resonators and determine the dynamic coupling coefficient using a simple analytic model. We show that plasmonic resonators, such as subwavelength holes in a metal film which can be treated as bound charge oscillators, couple to each other through the retarded interaction of oscillating screened charges. Our dynamic coupling model offers, for the first time, a quantitative analytic description of the fundamental symmetric and anti-symmetric modes of coupled resonators which agrees with experimental results. Our model also reveals that plasmonic electromagnetically induced transparency arises in any coupled resonators of slightly unequal lengths, as confirmed by a rigorous numerical calculation and experiments. PMID:26911786

  8. Magneto-electric interactions at bending resonance in an asymmetric multiferroic composite: Theory and experiment on the influence of electrode position

    NASA Astrophysics Data System (ADS)

    Sreenivasulu, G.; Qu, P.; Petrov, V. M.; Qu, Hongwei; Srinivasan, G.

    2015-05-01

    In magnetostrictive-piezoelectric bilayers the strength of mechanical strain mediated magneto-electric (ME) interactions shows a resonance enhancement at bending modes. Such composites when operating under frequency modulation at bending resonance have very high ME sensitivity and are of importance for ultrasensitive magnetometers. This report provides an avenue for further enhancement in the ME sensitivity by strategic positioning of the electrodes in the bilayer. We discuss the theory and measurements on the dependence of ME coupling on the position of electrodes in a lead zirconate titanate-permendur bilayer. Samples of effective length L with full electrodes and partial electrodes of length l = L/3 are studied. A five-fold increase in ME voltage coefficient (MEVC) at bending resonance and a 75% increase in low-frequency MEVC are measured as the partial electrode position is moved from the free-end to clamped-end of the bilayer. When the partial electrode is close to the clamped end, the low-frequency and resonance MEVC are 22% and 45% higher, respectively, than for fully electroded bilayer. According to the model discussed here these observations could be attributed to non-uniform stress along the sample length under flexural deformation. Such deformations are stronger at the free-end than at the clamped-end, thereby reducing the stress produced by applied magnetic fields and a reduction in MEVC. Estimates of MEVC are in good agreement with the data.

  9. Influence of resonance interactions and matrix environment on the spectra of SF(6) dimers in low-temperature nitrogen matrixes. Theory and experiment.

    PubMed

    Tokhadze, Irina K; Kolomiitsova, Tatjana D; Shchepkin, Dmitrii N; Tokhadze, Konstantin G; Mielke, Zofia

    2009-06-01

    The IR absorption spectra of (SF(6))(2) dimers were studied in N(2) matrixes at 11 K. Absorption bands due to SF(6) monomers and to (SF(6))(2) dimers have been identified. As a result of the resonance dipole-dipole interaction between two SF(6) subunits, the band of the triply degenerate vibration nu(3) is split into two components nu(X),(Y) and nu(Z), where Z is the axis connecting the two sulfur atoms. The main distinction between the spectra of (SF(6))(2) dimers recorded here compared to spectra in the gas phase is the splitting of the nu(X),(Y) component. A model that takes into account the influence of the matrix on the spectra of dimers is developed. The model makes it possible to successively (i) calculate the resonance spectrum of an isolated dimer in terms of the model of local modes including the resonance interactions, (ii) determine with the help of the Monte Carlo method the structure of a matrix consisting of 864 N(2) molecules and a rigid (SF(6))(2) dimer, and (iii) take into account the interactions of local dipole moments of a dimer with host particles in the approximation of dipole-induced dipole and dipole-quadrupole interactions. The calculated spectra sufficiently well reproduce the main characteristics of the experimental spectra in N(2) matrixes, in particular, the decrease of the resonance splitting upon transition from the gas phase to a matrix and the splitting of nu(X,Y) component in the nitrogen matrix. PMID:19438235

  10. Resonant Auger decay of Xe{sup *} 4d{sub 5/2}{sup -1}6p: A contribution to the complete experiment from fluorescence polarization studies

    SciTech Connect

    O'Keeffe, P.; Aloiese, S.; Meyer, M.; Lohmann, B.; Kleiman, U.; Grum-Grzhimailo, A. N.

    2004-07-01

    Fluorescence polarimetry has been used to determine the relative partial-wave Auger decay widths for transitions to states of the Xe II 5p{sup 4}6p multiplet after photoexcitation of the Xe{sup *} 4d{sub 5/2}{sup -1}6p(J{sup *}=1) resonance by linearly and circularly polarized synchrotron radiation. Combination with data on the angular distribution and spin polarization of the Auger electrons, providing information on the relative phases of the amplitudes, constitutes the complete experiment on the Auger decay. Multiconfiguration relativistic calculations of the amplitudes have been performed and compared to the measurements.

  11. Laser Resonator

    NASA Technical Reports Server (NTRS)

    Harper, L. L. (Inventor)

    1983-01-01

    An optical resonator cavity configuration has a unitary mirror with oppositely directed convex and concave reflective surfaces disposed into one fold and concertedly reversing both ends of a beam propagating from a laser rod disposed between two total internal reflection prisms. The optical components are rigidly positioned with perpendicularly crossed virtual rooflines by a compact optical bed. The rooflines of the internal reflection prisms, are arranged perpendicularly to the axis of the laser beam and to the optical axes of the optical resonator components.

  12. Discrete resonances

    NASA Astrophysics Data System (ADS)

    Vivaldi, Franco

    2015-12-01

    The concept of resonance has been instrumental to the study of Hamiltonian systems with divided phase space. One can also define such systems over discrete spaces, which have a finite or countable number of points, but in this new setting the notion of resonance must be re-considered from scratch. I review some recent developments in the area of arithmetic dynamics which outline some salient features of linear and nonlinear stable (elliptic) orbits over a discrete space, and also underline the difficulties that emerge in their analysis.

  13. Discrete resonances

    NASA Astrophysics Data System (ADS)

    Vivaldi, Franco

    The concept of resonance has been instrumental to the study of Hamiltonian systems with divided phase space. One can also define such systems over discrete spaces, which have a finite or countable number of points, but in this new setting the notion of resonance must be re-considered from scratch. I review some recent developments in the area of arithmetic dynamics which outline some salient features of linear and nonlinear stable (elliptic) orbits over a discrete space, and also underline the difficulties that emerge in their analysis.

  14. Investigation of Very Slowly Tumbling Spin Labels by Nonlinear Spin Response Techniques: Theory and Experiment for Stationary Electron Electron Double Resonance

    PubMed Central

    Smigel, Murray D.; Dalton, Larry R.; Hyde, James S.; Dalton, Lauraine A.

    1974-01-01

    The investigation of very slowly tumbling spin labels by nonlinear electron spin response techniques is discussed. Such techniques permit characterization of rotational processes with correlation times from 10-3 to 10-7 sec even though the linear spin response (ESR) technique is insensitive to motion in this region. Nonlinear techniques fall into two categories: (a) Techniques (referred to as passage techniques) in which the distribution of saturation throughout the spin system is determined both by the applied magnetic field modulation of the resonance condition and by the modulation of the resonance frequency induced by the molecular motion. The time dependence of this distribution produces phase and amplitude changes in the observed signals. (b) Techniques that measure the integral of the distribution function of the time required for saturated spin packets to move between pumped and observed portions of the spectrum [stationary and pulsed electron electron double resonance (ELDOR) techniques]. Quantitative analysis of passage ESR and stationary ELDOR techniques can be accomplished employing a density matrix treatment that explicitly includes the interaction of the spins with applied radiation and modulation fields. The effect of molecular motion inducing a random modulation of the anisotropic spin interactions can be calculated by describing the motion by the diffusion equation appropriate to the motional model assumed. For infinitesimal steps the eigen-functions of the diffusion operator are known analytically, while for random motion of arbitrary step size they are determined by diagonalizing the transition matrix appropriate for the step model used. The present communication reports investigation of the rotational diffusion of the spin label probes 2,2,6,6-tetramethyl-4-piperidinol-1-oxyl and 17β-hydroxy-4′,4′-dimethylspiro-[5α-androstane-3,2′-oxazolidin]-3′-oxyl in sec-butylbenzene. Experimental spectra are compared with computer simulations of spectra carried out for isotropic Brownian (limit of infinitesimal step size) and free diffusion (arbitrary step size) models. PMID:4365576

  15. Autostereogram resonators

    NASA Astrophysics Data System (ADS)

    Leavey, Sean; Rae, Katherine; Murray, Adam; Courtial, Johannes

    2012-09-01

    Autostereograms, or "Magic Eye" pictures, are repeating patterns designed to give the illusion of depth. Here we discuss optical resonators that create light patterns which, when viewed from a suitable position by a monocular observer, are autostereograms of the three-dimensional shape of one of the mirror surfaces.

  16. Accuracy of magnetic resonance cholangiography compared to operative endoscopy in detecting biliary stones, a single center experience and review of literature

    PubMed Central

    Polistina, Francesco A; Frego, Mauro; Bisello, Marco; Manzi, Emy; Vardanega, Antonella; Perin, Bortolo

    2015-01-01

    AIM: To compare diagnostic sensitivity, specificity and accuracy of magnetic resonance cholangiopancreatography (MRCP) without contrast medium and endoscopic ultrasound (EUS)/endoscopic retrograde cholangiopancreatography (ERCP) for biliary calculi. METHODS: From January 2012 to December 2013, two-hundred-sixty-three patients underwent MRCP at our institution, all MRCP procedure were performed with the same machinery. In two-hundred MRCP was done for pure hepatobiliary symptoms and these patients are the subjects of this study. Among these two-hundred patients, one-hundred-eleven (55.5%) underwent ERCP after MRCP. The retrospective study design consisted in the systematic revision of all images from MRCP and EUS/ERCP performed by two radiologist with a long experience in biliary imaging, an experienced endoscopist and a senior consultant in Hepatobiliopancreatic surgery. A false positive was defined an MRCP showing calculi with no findings at EUS/ERCP; a true positive was defined as a concordance between MRCP and EUS/ERCP findings; a false negative was defined as the absence of images suggesting calculi at MRCP with calculi localization/extraction at EUS/ERCP and a true negative was defined as a patient with no calculi at MRCP ad at least 6 mo of asymptomatic follow-up. Biliary tree dilatation was defined as a common bile duct diameter larger than 6 mm in a patient who had an in situ gallbladder. A third blinded radiologist who examined the MRCP and ERCP data reviewed misdiagnosed cases. Once obtained overall data on sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) we divided patients in two groups composed of those having concordant MRCP and EUS/ERCP (Group A, 72 patients) and those having discordant MRCP and EUS/ERCP (Group B, 20 patients). Dataset comparisons had been made by the Students t-test and ?2 when appropriate. RESULTS: Two-hundred patients (91 men, 109 women, mean age 67.6 years, and range 25-98 years) underwent MRCP. All patients attended regular follow-up for at least 6 mo. Morbidity and mortality related to MRCP were null. MRCP was the only exam performed in 89 patients because it did show only calculi into the gallbladder with no signs of the presence of calculi into the bile duct and symptoms resolved within a few days or after colecistectomy. The patients remained asymptomatic for at least 6 mo, and we assumed they were true negatives. One hundred eleven (53 men, 58 women, mean age 69 years, range 25-98 years) underwent ERCP following MRCP. We did not find any difference between the two groups in terms of race, age, and sex. The overall median interval between MRCP and ERCP was 9 d. In detecting biliary stones MRCP Sensitivity was 77.4%, Specificity 100% and Accuracy 80.5% with a PPV of 100% and NPV of 85%; EUS showed 95% sensitivity, 100% specificity, 95.5% accuracy with 100% PPV and 57.1% NPV. The association of EUS with ERCP performed at 100% in all the evaluated parameters. When comparing the two groups, we did not find any statistically significant difference regarding age, sex, and race. Similarly, we did not find any differences regarding the number of extracted stones: 116 stones in Group A (median 2, range 1 to 9) and 27 in Group B (median 2, range 1 to 4). When we compared the size of the extracted stones we found that the patients in Group B had significantly smaller stones: 14.16 8.11 mm in Group A and 5.15 2.09 mm in Group B; 95% confidence interval = 5.89-12.13, standard error = 1.577; P < 0.05. We also found that in Group B there was a significantly higher incidence of stones smaller than 5 mm: 36 in Group A and 18 in Group B, P < 0.05. CONCLUSION: Major finding of the present study is that choledocholithiasis is still under-diagnosed in MRCP. Smaller stones (< 5 mm diameter) are hardly visualized on MRCP. PMID:25918584

  17. Design and testing of a low impedance transceiver circuit for nitrogen-14 nuclear quadrupole resonance.

    PubMed

    Sato-Akaba, Hideo

    2014-01-01

    A low impedance transceiver circuit consisting of a transmit-receive switch circuit, a class-D amplifier and a transimpedance amplifier (TIA) was newly designed and tested for a nitrogen-14 NQR. An NQR signal at 1.37MHz from imidazole was successfully observed with the dead time of ~85µs under the high Q transmission (Q~120) and reception (Q~140). The noise performance of the low impedance TIA with an NQR probe was comparable with a commercial low noise 50Ω amplifier (voltage input noise: 0.25 nV/Hz) which was also connected to the probe. The protection voltage for the pre-amplifier using the low impedance transceiver was ~10 times smaller than that for the pre-amplifier using a 50Ω conventional transceiver, which is suitable for NQR remote sensing applications. PMID:25293696

  18. Fast response resonance fluorescence CO measurements aboard the C-130: Instrument characterization and measurements made during North Atlantic Regional Experiment 1993

    NASA Astrophysics Data System (ADS)

    Gerbig, Christoph; Kley, Dieter; Volz-Thomas, Andreas; Kent, Joss; Dewey, Ken; McKenna, Danny S.

    1996-12-01

    The resonance fluorescence instrument for the measurement of atmospheric CO described by Volz and Kley [1985] was characterized in the laboratory and adapted for use on aircraft. A major finding was that the background signal is largely due to continuum resonance Raman scattering by molecular oxygen and thus cannot be reduced by better design. The instrument was deployed on the United Kingdom Meteorological Office (UKMO) C-130 Hercules during August 1993 and in subsequent missions. The instrument achieved a detection limit (3σ) of 5 ppb at a time resolution of 30 s. For a typical CO concentration of 100 ppb, the signal-to-noise ratio (1σ) was 15 for an integration time of 2 s, which was the minimum time resolution that could be obtained during the flights because of limited pump capacity. Data collected over the North Atlantic show distinct layers of CO above the atmospheric boundary layer (ABL) that are well correlated with enhanced NOy mixing ratios and indicate transport of pollution from the American continent. Such layers, albeit much less pronounced, were encountered in westerly flow in the midtroposphere west of the coast of Portugal. Fairly high mixing ratios were observed in the lower troposphere associated with transport from southern Europe.

  19. Polariton path to fully resonant dispersive coupling in optomechanical resonators

    NASA Astrophysics Data System (ADS)

    Rozas, G.; Bruchhausen, A. E.; Fainstein, A.; Jusserand, B.; Lemaître, A.

    2014-11-01

    Resonant photoelastic coupling opens new perspectives for strongly enhanced light-sound interaction in semiconductor optomechanical resonators. One potential problem, however, is the reduction of the cavity Q factor induced by dissipation when the resonance is approached. We show in this Rapid Communication through Raman-scattering experiments that cavity-polariton mediation in the light-matter process overcomes this limitation allowing for a strongly enhanced photon-phonon coupling without significant lifetime reduction in the strong-coupling regime. Huge optomechanical coupling factors in the petaHz/nm range are envisaged, three orders of magnitude larger than the backaction produced by the mechanical displacement of the cavity mirrors.

  20. Resonant behavior of dielectric objects (electrostatic resonances).

    PubMed

    Fredkin, D R; Mayergoyz, I D

    2003-12-19

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

  1. An Electromagnetic Resonance Circuit for Liquid Level Detection

    ERIC Educational Resources Information Center

    Hauge, B. L.; Helseth, L. E.

    2012-01-01

    Electromagnetic resonators are often used to detect foreign materials. Here we present a simple experiment for the measurement of liquid level. The resonator, consisting of a coil and a capacitor, is brought to resonance by an external magnetic field source, and the corresponding resonance frequency is determined using Fourier analysis combined

  2. An Electromagnetic Resonance Circuit for Liquid Level Detection

    ERIC Educational Resources Information Center

    Hauge, B. L.; Helseth, L. E.

    2012-01-01

    Electromagnetic resonators are often used to detect foreign materials. Here we present a simple experiment for the measurement of liquid level. The resonator, consisting of a coil and a capacitor, is brought to resonance by an external magnetic field source, and the corresponding resonance frequency is determined using Fourier analysis combined…

  3. Fundamental mode rectangular waveguide system for electron-cyclotron resonant heating (ECRH) for tandem mirror experiment-upgrade (TMX-U)

    SciTech Connect

    Rubert, R.R.; Felker, B.; Stallard, B.W.; Williams, C.W.

    1983-12-01

    We present a brief history of TMX-U's electron cyclotron resonant heating (ECRH) progress. We emphasize the 2-year performance of the system, which is composed of four 200-kW pulsed gyrotrons operated at 28 GHz. This system uses WR42 waveguide inside the vacuum vessel, and includes barrier windows, twists, elbows, and antennas, as well as custom-formed waveguides. Outside the TMX-U vessel are directional couplers, detectors, elbows, and waveguide bends in WR42 rectangular waveguide. An arc detector, mode filter, eight-arm mode converter, and water load in the 2.5-in. circular waveguide are attached directly to the gyrotron. Other specific areas discussed include the operational performance of the TMX-U pulsed gyrotrons, windows and component arcing, alignment, mode generation, and extreme temperature variations. Solutions for a number of these problems are described.

  4. Time-Resolved Magnetic Resonance Angiography in the Evaluation of Intracranial Vascular Lesions and Tumors: A Pictorial Essay of Our Experience.

    PubMed

    Liu, Ming-Cheng; Chen, Hung-Chieh; Wu, Chen-Hao; Chen, Wen-Hsien; Tsuei, Yuang-Seng; Chen, Clayton Chi-Chang

    2015-11-01

    Time-resolved magnetic resonance angiography (TR MRA) is a promising less invasive technique for the diagnosis of intracranial vascular lesions and hypervascular tumors. Similar to 4-dimensional computed tomographic angiography obtaining high frame rate images, TR MRA utilizes acceleration techniques to acquire sequential arterial and venous phase images for identifying, localizing, and classifying vascular lesions. Because of the good agreement with digital subtraction angiography for grading brain arteriovenous malformations with the Spetzler-Martin classification and the good sensitivity for visualizing arteriovenous fistulas, studies have suggested that TR MRA could serve as a screening or routine follow-up tool for diagnosing intracranial vascular disorders. In this pictorial essay, we report on the use of TR MRA at 3.0 T to diagnose intracranial vascular lesions and hypervascular tumors, employing DSA as the reference technique. PMID:26277233

  5. Gravitoelectromagnetic resonances

    NASA Astrophysics Data System (ADS)

    Tsagas, Christos G.

    2011-08-01

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

  6. Resonant ultrasonic attenuation in emulsions

    NASA Astrophysics Data System (ADS)

    Brunet, Thomas; Mascaro, Benoit; Poncelet, Olivier; Aristégui, Christophe; Raffy, Simon; Mondain-Monval, Olivier; Leng, Jacques

    2013-08-01

    We report the achievement of scattering resonant emulsions devoted to the frequency-control of acoustic attenuation in the megahertz range. By means of robotics, we produced highly monodisperse, in both size and shape, fluorinated-oil droplet suspensions, providing experimental evidence of several Mie scattering resonances. Ultrasonic experiments performed in such complex media are compared, with an excellent quantitative agreement, to theoretical predictions derived within the framework of the independent scattering approximation.

  7. Magnetic resonance fingerprinting.

    PubMed

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

    2013-03-14

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

  8. Mixed-radiation-field dosimetry utilizing Nuclear Quadrupole Resonance. Final report

    SciTech Connect

    Hintenlang, D.E.; Jamil, K.; Iselin, L.H.

    1992-12-31

    Radiation effects on urea, thiourea, guanidine carbonate and guanine sulfate were evaluated for both photon and neutron irradiations. Hydration of these materials typically provides a greatly increased sensitivity to both forms of radiation exposure, although not all materials lend themselves to this treatment without changing the chemical structure of the compound. Urea was found to be the most stable hydrated compound and provides the best sensitivity for quantifying radiation effects using NQR techniques. Urea permits a straight-forward quantification of each of the important parameters of the observed NQR signal, the FID. Several advanced data analysis methods were developed to assist in quantifying NQR spectra, both from urea and materials having more complex molecular structures, such as thiourea and guanidine sulfate. Unfortunately, these analysis techniques are frequently quite time consuming for the complex NQR spectra that result from some of these materials. The simpler analysis afforded by urea has therefore made it the prime candidate for an NQR dosimetry material. The moderate sensitivity of hydrated urea to photon irradiation does not permit this material to achieve the levels of performance required for a personnel dosimeter. It does, however, demonstrate acceptable sensitivity over dose ranges where it could provide a good biological dosimeter for several areas of radiation processing. The demonstrated photon sensitivity could permit hydrated urea to be used in applications such as food irradiation dosimetry. This material also exhibits a good sensitivity to neutron irradiation. The precise correlation between neutron exposure and the parameters of the resulting NQR spectra are currently being developed.

  9. 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.

  10. Prostate Postbrachytherapy Seed Distribution: Comparison of High-Resolution, Contrast-Enhanced, T1- and T2-Weighted Endorectal Magnetic Resonance Imaging Versus Computed Tomography: Initial Experience

    SciTech Connect

    Bloch, B. Nicolas Lenkinski, Robert E.; Helbich, Thomas H.; Ngo, Long; Oismueller, Renee; Jaromi, Silvia; Kubin, Klaus; Hawliczek, Robert; Kaplan, Irving D.; Rofsky, Neil M.

    2007-09-01

    Purpose: To compare contrast-enhanced, T1-weighted, three-dimensional magnetic resonance imaging (CEMR) and T2-weighted magnetic resonance imaging (T2MR) with computed tomography (CT) for prostate brachytherapy seed location for dosimetric calculations. Methods and Materials: Postbrachytherapy prostate MRI was performed on a 1.5 Tesla unit with combined surface and endorectal coils in 13 patients. Both CEMR and T2MR used a section thickness of 3 mm. Spiral CT used a section thickness of 5 mm with a pitch factor of 1.5. All images were obtained in the transverse plane. Two readers using CT and MR imaging assessed brachytherapy seed distribution independently. The dependency of data read by both readers for a specific subject was assessed with a linear mixed effects model. Results: The mean percentage ({+-} standard deviation) values of the readers for seed detection and location are presented. Of 1205 implanted seeds, CEMR, T2MR, and CT detected 91.5% {+-} 4.8%, 78.5% {+-} 8.5%, and 96.1% {+-} 2.3%, respectively, with 11.8% {+-} 4.5%, 8.5% {+-} 3.5%, 1.9% {+-} 1.0% extracapsular, respectively. Assignment to periprostatic structures was not possible with CT. Periprostatic seed assignments for CEMR and T2MR, respectively, were as follows: neurovascular bundle, 3.5% {+-} 1.6% and 2.1% {+-} 0.9%; seminal vesicles, 0.9% {+-} 1.8% and 0.3% {+-} 0.7%; periurethral, 7.1% {+-} 3.3% and 5.8% {+-} 2.9%; penile bulb, 0.6% {+-} 0.8% and 0.3% {+-} 0.6%; Denonvillier's Fascia/rectal wall, 0.5% {+-} 0.6% and 0%; and urinary bladder, 0.1% {+-} 0.3% and 0%. Data dependency analysis showed statistical significance for the type of imaging but not for reader identification. Conclusion: Both enumeration and localization of implanted seeds are readily accomplished with CEMR. Calculations with MRI dosimetry do not require CT data. Dose determinations to specific extracapsular sites can be obtained with MRI but not with CT.

  11. 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…

  12. Systematic 12- and 13-core transrectal ultrasound- or magnetic resonance imaging-guided biopsies significantly improve prostate cancer detection rate: A single-center 13-year experience

    PubMed Central

    CHENG, GONG; HUANG, YUAN; LIU, BIANJIANG; ZHAO, RUIZHE; SHAO, PENGFEI; LI, JIE; QIN, CHAO; HUA, LIXIN; YIN, CHANGJUN

    2014-01-01

    The aim of the present study was to evaluate the value of systematic 12- and 13-core biopsies, guided by transrectal ultrasound (TRUS) or magnetic resonance imaging (MRI), with regard to the prostate cancer detection rate (PCDR). Between July 1999 and June 2012, 2,707 patients were recruited to the Department of Urology, The First Affiliated Hospital of Nanjing Medical University (Nanjing, China). Prostate biopsies were performed via systematic 12- or 13-core biopsy and guided by either TRUS or MRI. The PCDR was established by retrospectively analyzing the distribution of positive cores, and it was assumed that all patients had undergone four biopsy schemes: Medial 6-core, lateral 6-core, 12-core and entire 13-core. In addition, the positive rate of the biopsies with the extra 13th core and the mean positive rate of systematic 12-core biopsies were compared. The PCDR of an entire 13-core biopsy was significantly higher than that of a lateral 6-core biopsy. The positive rate of the extra 13th core, which identified abnormal TRUS or MRI findings, was significantly higher when compared with that of the mean positive rate of the systematic 12-core biopsy. The results of the present study demonstrated that the entire 13-core biopsy was superior to the 6-core biopsy with regard to the PCDR. Therefore, the systematic 12-core biopsy with an extra 13th core is considered to be beneficial towards improving the PCDR. PMID:25202421

  13. Fast scintillation timing detector using proportional-mode avalanche photodiode for nuclear resonant scattering experiments in high-energy synchrotron X-ray region

    NASA Astrophysics Data System (ADS)

    Inoue, Keisuke; Kishimoto, Shunji

    2016-01-01

    To obtain both a high count rate of >107 s-1 and a detection efficiency sufficient for high-energy X-rays of >30 keV, we propose a scintillation timing detector using a proportional-mode silicon avalanche photodiode (Si-APD) for synchrotron radiation nuclear resonant scattering. We here present results obtained with a prototype detector using a lead-loaded plastic scintillator (EJ-256) mounted on a proportional-mode Si-APD (active area size: 3 mm in diameter). The detector was operated at ‒35 °C for a better signal-to-noise ratio. Using synchrotron X-rays of 67.41 keV, which is the same energy as the first excited level of 61Ni, we successfully measured pulse-height and time spectra of the scintillation light. A good time resolution of 0.50±0.06 ns (full width at half-maximum) was obtained for 67.41 keV X-rays with a scintillator 3 mm in diameter and 2 mm thick.

  14. Cavities for electron spin resonance: predicting the resonant frequency

    NASA Astrophysics Data System (ADS)

    Colton, John; Miller, Kyle; Meehan, Michael; Spencer, Ross

    Microwave cavities are used in electron spin resonance to enhance magnetic fields. Dielectric resonators (DRs), pieces of high dielectric material, can be used to tailor the resonant frequency of a cavity. However, designing cavities with DRs to obtain desired frequencies is challenging and in general can only be done numerically with expensive software packages. We present a new method for calculating the resonant frequencies and corresponding field modes for cylindrically symmetric cavities and apply it to a cavity with vertically stacked DRs. The modes of an arbitrary cavity are expressed as an expansion of empty cavity modes. The wave equation for D gives rise to an eigenvalue equation whose eigenvalues are the resonant frequencies and whose eigenvectors yield the electric and magnetic fields of the mode. A test against theory for an infinitely long dielectric cylinder inside an infinite cavity yields an accuracy better than 0.4% for nearly all modes. Calculated resonant frequencies are also compared against experiment for quasi-TE011 modes in resonant cavities with ten different configurations of DRs; experimental results agree with predicted values with an accuracy better than 1.0%. MATLAB code is provided at http://www.physics.byu.edu/research/coltonlab/cavityresonance.

  15. Magnetic Resonance Imaging (MRI) with retrograde intralumen contrast enhancement of the rectum in diagnostics of rectovaginal fistulas after combination therapy of rectal cancer. Experience of application

    NASA Astrophysics Data System (ADS)

    Usova, A.; Frolova, I.; Afanasev, S.; Tarasova, A.; Molchanov, S.

    2016-02-01

    Experiment of use of MRI in diagnostics of rectovaginal fistulas after combination therapy of rectal cancer is shown on clinical examples. We used retrograde contrasting of a rectum with 150ml ultrasonic gel to make MRI more informative in case of low diagnostic efficiency of ultrasound, colonoscopy and gynecological examination.

  16. Silicon photonic resonator sensors and devices

    NASA Astrophysics Data System (ADS)

    Chrostowski, Lukas; Grist, Samantha; Flueckiger, Jonas; Shi, Wei; Wang, Xu; Ouellet, Eric; Yun, Han; Webb, Mitch; Nie, Ben; Liang, Zhen; Cheung, Karen C.; Schmidt, Shon A.; Ratner, Daniel M.; Jaeger, Nicolas A. F.

    2012-02-01

    Silicon photonic resonators, implemented using silicon-on-insulator substrates, are promising for numerous applications. The most commonly studied resonators are ring/racetrack resonators. We have fabricated these and other resonators including disk resonators, waveguide-grating resonators, ring resonator reflectors, contra-directional grating-coupler ring resonators, and racetrack-based multiplexer/demultiplexers. While numerous resonators have been demonstrated for sensing purposes, it remains unclear as to which structures provide the highest sensitivity and best limit of detection; for example, disc resonators and slot-waveguide-based ring resonators have been conjectured to provide an improved limit of detection. Here, we compare various resonators in terms of sensor metrics for label-free bio-sensing in a micro-fluidic environment. We have integrated resonator arrays with PDMS micro-fluidics for real-time detection of biomolecules in experiments such as antigen-antibody binding reaction experiments using Human Factor IX proteins. Numerous resonators are fabricated on the same wafer and experimentally compared. We identify that, while evanescent-field sensors all operate on the principle that the analyte's refractive index shifts the resonant frequency, there are important differences between implementations that lie in the relationship between the optical field overlap with the analyte and the relative contributions of the various loss mechanisms. The chips were fabricated in the context of the CMC-UBC Silicon Nanophotonics Fabrication course and workshop. This yearlong, design-based, graduate training program is offered to students from across Canada and, over the last four years, has attracted participants from nearly every Canadian university involved in photonics research. The course takes students through a full design cycle of a photonic circuit, including theory, modelling, design, and experimentation.

  17. Humanitarian mine detection by acoustic resonance

    SciTech Connect

    Kercel, S.W.

    1998-03-01

    The JASON Committee at MITRE Corp. was tasked by DARPA to inquire into suitable technologies for humanitarian mine detection. Acoustic resonance was one of the very few technologies that the JASONs determined might be promising for the task, but was as yet unexplored at the time that they conducted their inquiry. The objective of this Seed Money investigation into acoustic resonance was to determine if it would be feasible to use acoustic resonance to provide an improvement to present methods for humanitarian mine detection. As detailed in this report, acoustic resonance methods do not appear to be feasible for this task. Although acoustic resonant responses are relatively easy to detect when they exist, they are very difficult to excite by the non-contact means that must be used for buried objects. Despite many different attempts, this research did not discover any practical means of using sound to excite resonant responses in objects known to have strong resonances. The shaker table experiments did see an effect that might be attributable to the resonance of the object under test, but the effect was weak, and exploited the a priori knowledge of the resonant frequency of the object under test to distinguish it from the background. If experiments that used objects known to have strong acoustic resonances produced such marginal results, this does not seem to be a practical method to detect objects with weak resonances or non-existent resonances. The results of this work contribute to the ORNL countermine initiative. ORNL is exploring several unconventional mine detection technologies, and is proposed to explore others. Since this research has discovered some major pitfalls in non-metallic mine detection, this experience will add realism to other strategies proposed for mine detection technologies. The experiment provided hands-on experience with inert plastic mines under field conditions, and gives ORNL additional insight into the problems of developing practical field-deployable methods of mine detection.

  18. RCNP E398 {sup 16}O,{sup 12}C(p,p’) experiment: Measurement of the γ-ray emission probability from giant resonances in relation to {sup 16}O,{sup 12}C(ν,ν’) reactions

    SciTech Connect

    Ou, I.; Yamada, Y.; Mori, T.; Yano, T.; Sakuda, M.; Tamii, A.; Suzuki, T.; Yosoi, M.; Aoi, N.; Ideguchi, E.; Hashimoto, T.; Miki, K.; Ito, T.; Iwamoto, C.; Yamamoto, T.; Akimune, H.

    2015-05-15

    We propose to measure the γ-ray emission probability from excited states above 5 MeV including giant resonance of {sup 16}O and {sup 12}C as a function of excitation energy in 1-MeV step. Here, we measure both the excitation energy (E{sub x}=5-30MeV) at the forward scattering angles (0°-3°) of the {sup 16}O, {sup 12}C (p, p’) reaction using Grand-Raiden Spectrometer and the energy of γ-rays (E{sub γ}) using an array of NaI(Tl) counters. The purpose of the experiment is to provide the basic and important information not only for the γ-ray production from primary neutral-current neutrino-oxygen (-carbon) interactions but also for that from the secondary hadronic (neutron-oxygen and -carbon) interactions.

  19. Nested trampoline resonators for optomechanics

    NASA Astrophysics Data System (ADS)

    Weaver, M. J.; Pepper, B.; Luna, F.; Buters, F. M.; Eerkens, H. J.; Welker, G.; Perock, B.; Heeck, K.; de Man, S.; Bouwmeester, D.

    2016-01-01

    Two major challenges in the development of optomechanical devices are achieving a low mechanical and optical loss rate and vibration isolation from the environment. We address both issues by fabricating trampoline resonators made from low pressure chemical vapor deposition Si3N4 with a distributed Bragg reflector mirror. We design a nested double resonator structure with 80 dB of mechanical isolation from the mounting surface at the inner resonator frequency, and we demonstrate up to 45 dB of isolation at lower frequencies in agreement with the design. We reliably fabricate devices with mechanical quality factors of around 400 000 at room temperature. In addition, these devices were used to form optical cavities with finesse up to 181 000 ± 1000. These promising parameters will enable experiments in the quantum regime with macroscopic mechanical resonators.

  20. High Spatial Resolution Cardiovascular Magnetic Resonance at 7.0 Tesla in Patients with Hypertrophic Cardiomyopathy – First Experiences: Lesson Learned from 7.0 Tesla

    PubMed Central

    Prothmann, Marcel; von Knobelsdorff-Brenkenhoff, Florian; Töpper, Agnieszka; Dieringer, Matthias A.; Shahid, Etham; Graessl, Andreas; Rieger, Jan; Lysiak, Darius; Thalhammer, C.; Huelnhagen, Till; Kellman, Peter; Niendorf, Thoralf; Schulz-Menger, Jeanette

    2016-01-01

    Background Cardiovascular Magnetic Resonance (CMR) provides valuable information in patients with hypertrophic cardiomyopathy (HCM) based on myocardial tissue differentiation and the detection of small morphological details. CMR at 7.0T improves spatial resolution versus today’s clinical protocols. This capability is as yet untapped in HCM patients. We aimed to examine the feasibility of CMR at 7.0T in HCM patients and to demonstrate its capability for the visualization of subtle morphological details. Methods We screened 131 patients with HCM. 13 patients (9 males, 56 ±31 years) and 13 healthy age- and gender-matched subjects (9 males, 55 ±31years) underwent CMR at 7.0T and 3.0T (Siemens, Erlangen, Germany). For the assessment of cardiac function and morphology, 2D CINE imaging was performed (voxel size at 7.0T: (1.4x1.4x2.5) mm3 and (1.4x1.4x4.0) mm3; at 3.0T: (1.8x1.8x6.0) mm3). Late gadolinium enhancement (LGE) was performed at 3.0T for detection of fibrosis. Results All scans were successful and evaluable. At 3.0T, quantification of the left ventricle (LV) showed similar results in short axis view vs. the biplane approach (LVEDV, LVESV, LVMASS, LVEF) (p = 0.286; p = 0.534; p = 0.155; p = 0.131). The LV-parameters obtained at 7.0T where in accordance with the 3.0T data (pLVEDV = 0.110; pLVESV = 0.091; pLVMASS = 0.131; pLVEF = 0.182). LGE was detectable in 12/13 (92%) of the HCM patients. High spatial resolution CINE imaging at 7.0T revealed hyperintense regions, identifying myocardial crypts in 7/13 (54%) of the HCM patients. All crypts were located in the LGE-positive regions. The crypts were not detectable at 3.0T using a clinical protocol. Conclusions CMR at 7.0T is feasible in patients with HCM. High spatial resolution gradient echo 2D CINE imaging at 7.0T allowed the detection of subtle morphological details in regions of extended hypertrophy and LGE. PMID:26863618

  1. Magnetic Resonance Imaging (MRI)

    MedlinePlus

    ... How Can I Help a Friend Who Cuts? Magnetic Resonance Imaging (MRI) KidsHealth > For Teens > Magnetic Resonance Imaging (MRI) Print ... MRI Exam Safety Getting Your Results What Is MRI? Magnetic resonance imaging (MRI) is a type of ...

  2. Extraordinary acoustic transmission mediated by Helmholtz resonators

    SciTech Connect

    Koju, Vijay; Rowe, Ebony; Robertson, William M.

    2014-07-15

    We demonstrate perfect transmission of sound through a rigid barrier embedded with Helmholtz resonators. The resonators are confined within a waveguide and they are oriented such that one neck protrudes onto each side of the barrier. Perfect sound transmission occurs even though the open area of the necks is less than 3% of the barrier area. Maximum transmission occurs at the resonant frequency of the Helmholtz resonator. Because the dimensions of the Helmholtz resonators are much smaller than the resonant wavelength, the transmission is independent of the direction of sound on the barrier and of the relative placement of the necks. Further, we show that the transmitted sound experiences a continuous phase transition of π radians as a function of frequency through resonance. In simulations of adjacent resonators with slightly offset resonance frequencies, the phase difference leads to destructive interference. By expanding the simulation to a linear array of tuned Helmholtz resonators we show that it is possible to create an acoustic lens. The ability of Helmholtz resonator arrays to manipulate the phase of a plane acoustic wave enables a new class of sonic beam-forming devices analogous to diffractive optics.

  3. Regenerative feedback resonant circuit

    DOEpatents

    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.

  4. Elemental bioimaging of thulium in mouse tissues by laser ablation-ICPMS as a complementary method to heteronuclear proton magnetic resonance imaging for cell tracking experiments.

    PubMed

    Reifschneider, Olga; Wentker, Kristina S; Strobel, Klaus; Schmidt, Rebecca; Masthoff, Max; Sperling, Michael; Faber, Cornelius; Karst, Uwe

    2015-04-21

    Due to the fact that cellular therapies are increasingly finding application in clinical trials and promise success by treatment of fatal diseases, monitoring strategies to investigate the delivery of the therapeutic cells to the target organs are getting more and more into the focus of modern in vivo imaging methods. In order to monitor the distribution of the respective cells, they can be labeled with lanthanide complexes such as thulium-1,4,7,10-tetraazacyclodoecane-α,α,α,α-tetramethyl-1,4,7,10-tetraacetic acid (Tm(DOTMA)). In this study, experiments on a mouse model with two different cell types, namely, tumor cells and macrophages labeled with Tm(DOTMA), were performed. The systemic distribution of Tm(DOTMA) of both cell types was investigated by means of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICPMS). Using the high resolution of 25 μm, distribution maps of Tm in different tissues such as tumor, liver, lung, and spleen as well as in explanted gel pellets were generated and the behavior of the labeled cells inside the tissue was investigated. Additionally, quantitative data were obtained using homemade matrix-matched standards based on egg yolk. Using this approach, limits of detection and quantification of 2.2 and 7.4 ng·g(-1), respectively, and an excellent linearity over the concentration range from 0.01 to 46 μg·g(-1) was achieved. The highest concentration of the label agent, 32.4 μg·g(-1), in tumor tissue was observed in the area of the injection of the labeled tumor cells. Regarding the second experiment with macrophages for cell tracking, Tm was detected in the explanted biogell pellet with relatively low concentrations below 60 ng·g(-1) and in the liver with a relatively high concentration of 10 μg·g(-1). Besides thulium, aluminum was detected with equal distribution behavior in the tumor section due to a contamination resulting from the labeling procedure, which includes the usage of an Al electrode. PMID:25791208

  5. Empathy in schizophrenia: impaired resonance.

    PubMed

    Haker, Helene; Rössler, Wulf

    2009-09-01

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

  6. Measuring the acoustic response of Helmholtz resonators

    NASA Astrophysics Data System (ADS)

    Monteiro, Martín; Marti, Arturo C.; Vogt, Patrik; Kasper, Lutz; Quarthal, Dominik

    2015-04-01

    Many experiments have been proposed to investigate acoustic phenomena in college and early undergraduate levels, in particular the speed of sound,1-9 by means of different methods, such as time of flight, transit time, or resonance in tubes. In this paper we propose to measure the acoustic response curves of a glass beaker filled with different gases, used as an acoustic resonator. We show that these curves expose many interesting peaks and features, one of which matches the resonance peak predicted for a Helmholtz resonator fairly well, and gives a decent estimate for the speed of sound in some cases. The measures are obtained thanks to the capabilities of smartphones.

  7. Acoustic resonance in heat exchanger tube bundles

    SciTech Connect

    Blevins, R.D. )

    1994-02-01

    A series of experiments has been made on aeroacoustic tones produced by flow over tubes in a duct. The sound is characterized by the onset of a loud and persistent acoustic resonance. The acoustic resonance occurs at the frequency of the acoustic modes. The magnitude and extent of the resonance are functions of tube pattern and tube pitch. The sound levels increase in proportion with Mach number, dynamic head and pressure drop. A design procedure for predicting the magnitude of the sound within the tube array is presented. Methods of resonance avoidance are illustrated. An example is made for a large petrochemical heat exchanger.

  8. Persistence, resistance, resonance

    NASA Astrophysics Data System (ADS)

    Tsadka, Maayan

    Sound cannot travel in a vacuum, physically or socially. The ways in which sound operates are a result of acoustic properties, and the ways by which it is considered to be music are a result of social constructions. Therefore, music is always political, regardless of its content: the way it is performed and composed; the choice of instrumentation, notation, tuning; the medium of its distribution; its inherent hierarchy and power dynamics, and more. My compositional praxis makes me less interested in defining a relationship between music and politics than I am in erasing---or at least blurring---the borders between them. In this paper I discuss the aesthetics of resonance and echo in their metaphorical, physical, social, and musical manifestations. Also discussed is a political aesthetic of resonance, manifested through protest chants. I transcribe and analyze common protest chants from around the world, categorizing and unifying them as universal crowd-mobilizing rhythms. These ideas are explored musically in three pieces. Sumud: Rhetoric of Resistance in Three Movements, for two pianos and two percussion players, is a musical interpretation of the political/social concept of sumud, an Arabic word that literally means "steadfastness" and represents Palestinian non-violent resistance. The piece is based on common protest rhythms and uses the acoustic properties inherent to the instruments. The second piece, Three Piano Studies, extends some of the musical ideas and techniques used in Sumud, and explores the acoustic properties and resonance of the piano. The final set of pieces is part of my Critical Mess Music Project. These are site-specific musical works that attempt to blur the boundaries between audience, performers and composer, in part by including people without traditional musical training in the process of music making. These pieces use the natural structure and resonance of an environment, in this case, locations on the UCSC campus, and offer an active form of musical consumption and experience. The three pieces draw lines connecting different aspects of persistence, resistance, and resonance.

  9. Resonance in a head massager

    NASA Astrophysics Data System (ADS)

    Ribeiro, Jair Lúcio Prados

    2015-04-01

    Mechanical structures such as pendula, bridges, or buildings always exhibit one (or more) natural oscillation frequency.1 If that structure is subjected to oscillatory forces of this same frequency, resonance occurs, with consequent increase of the structure oscillation amplitude. There is no shortage of simple experiments for demonstrating resonance in high school classes using a variety of materials, such as saw blades,2 guitars,3 pendulums,4 wine glasses,5 bottles,6 Ping-Pong balls,7 and pearl strings.8 We present here an experimental demonstration using only an inexpensive head (or scalp) massager, which can be purchased for less than a dollar.

  10. Structure and energetics of the anisole-Ar(n) (n = 1, 2, 3) complexes: high-resolution resonant two-photon and threshold ionization experiments, and quantum chemical calculations.

    PubMed

    Mazzoni, Federico; Becucci, Maurizio; Řezáč, Jan; Nachtigallová, Dana; Michels, François; Hobza, Pavel; Müller-Dethlefs, Klaus

    2015-05-21

    We present a concerted experimental and theoretical study of the anisole···Arn complexes with n = 1-3. Experimentally, anisole was seeded into a pulsed supersonic argon jet producing a molecular beam. Resonant two-photon, two-colour ionisation (R2PI) spectra of anisole···Arn complexes with n = 1-3 were obtained. Also, the photodissociation of the (1 : 1) cluster was probed synchronously by - Zero Electron Kinetic Energy Photoelectron Spectroscopy (ZEKE) - and - Mass Resolved Threshold Ionization (MATI) - measuring electrons and ions obtained from pulsed field ionization of high-n Rydberg states upon two-colour laser excitation. The experimental results are compared to quantum chemical calculations at the DFT-D3 (B-LYP/def2-QZVP level with Grimme's D3 dispersion correction) level. Structure and energetics due to microsolvation effects by the direct interaction of the argon atoms with the π-system were evaluated. The experimental binding energy of the 1 : 1 cluster is finally compared to computational results; in the S0 ground state the theoretical value based on the "gold standard" CCSD(T)/CBS calculations lies within the error bars of the observed value. In the excited state the agreement between theory and experiment is not so spectacular but relative values of observed dissociation energies (D0) in the ground and excited states and of calculated ones agree well. PMID:25899323

  11. Electroexcitation of nucleon resonances

    SciTech Connect

    Inna Aznauryan, Volker D. Burkert

    2012-01-01

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

  12. Cooling of a resonant circuit via laser cooled ions

    NASA Astrophysics Data System (ADS)

    Daniilidis, Nikos; Moeller, Soenke; Tabakov, Boyan; Bradley, Aaron; Haeffner, Hartmut

    2011-05-01

    We discuss our experimental progress towards coupling strings of trapped ions to an LC-resonator. The goal of our experiments is to cool the resonant mode of a superconducting high-quality resonant circuit to ultra-low temperatures. By continuously laser cooling a crystal of ions coupled to the circuit, energy is removed from the resonator. For quality factors on the order of 105, the time-scale of the environment-to-mode coupling, i.e. the time for the resonant mode of the LC-resonator to thermally equilibrate, can be on the order of a second. Thus, engineering an ion-resonator coupling of 10 kHz results in a reduction of the resonant mode temperature by four orders of magnitude as compared to the ambient temperature of the resonator. The expected temperatures, below 1 mK, approach the vibrational ground state of the oscillator mode.

  13. Coplanar photonic bandgap resonators for low temperature electron and nuclear magnetic resonance spectroscopy

    NASA Astrophysics Data System (ADS)

    Sigillito, A. J.; Tyryshkin, A. M.; Lyon, S. A.

    In recent years, superconducting coplanar waveguide (CPW) resonators have become a useful tool for low temperature pulsed electron spin resonance (ESR), even at dilution refrigerator temperatures. Their small mode volumes make CPW resonators particularly well suited to measuring small numbers of spins near the resonator surface, since in this region the spin sensitivity is very high. While these resonators have proven useful for ESR at single microwave frequencies, it is difficult to also manipulate nuclear spins in electron-nuclear-double resonance (ENDOR) experiments, since manipulation of nuclear spins requires radio frequency (RF) magnetic fields. Ideally one would simply generate these fields by passing RF currents through the CPW, but because conventional CPW resonators are capacitively coupled, they will not transmit low-frequency RF currents. In this talk, we discuss the use of one dimensional photonic bandgap (PBG) resonators to overcome this challenge. PBG resonators are a promising alternative to conventional CPW resonators since they offer high quality factors at microwave frequencies, while simultaneously allowing transmission of nonresonant RF currents below the photonic bandgap. Here, we will discuss PBG resonator designs and present data showing their use for low temperature ESR of donors in 28Si. Initial ENDOR results will also be presented.

  14. Stochastic resonance in visual sensitivity.

    PubMed

    Kundu, Ajanta; Sarkar, Sandip

    2015-04-01

    It is well known from psychophysical studies that stochastic resonance, in its simplest threshold paradigm, can be used as a tool to measure the detection sensitivity to fine details in noise contaminated stimuli. In the present manuscript, we report simulation studies conducted in the similar threshold paradigm of stochastic resonance. We have estimated the contrast sensitivity in detecting noisy sine-wave stimuli, with varying area and spatial frequency, as a function of noise strength. In all the cases, the measured sensitivity attained a peak at intermediate noise strength, which indicate the occurrence of stochastic resonance. The peak sensitivity exhibited a strong dependence on area and spatial frequency of the stimulus. We show that the peak contrast sensitivity varies with spatial frequency in a nonmonotonic fashion and the qualitative nature of the sensitivity variation is in good agreement with human contrast sensitivity function. We also demonstrate that the peak sensitivity first increases and then saturates with increasing area, and this result is in line with the results of psychophysical experiments. Additionally, we also show that critical area, denoting the saturation of contrast sensitivity, decreases with spatial frequency and the associated maximum contrast sensitivity varies with spatial frequency in a manner that is consistent with the results of psychophysical experiments. In all the studies, the sensitivities were elevated via a nonlinear filtering operation called stochastic resonance. Because of this nonlinear effect, it was not guaranteed that the sensitivities, estimated at each frequency, would be in agreement with the corresponding results of psychophysical experiments; on the contrary, close agreements were observed between our results and the findings of psychophysical investigations. These observations indicate the utility of stochastic resonance in human vision and suggest that this paradigm can be useful in psychophysical studies. PMID:25398687

  15. Electroweak-scale resonant leptogenesis

    SciTech Connect

    Pilaftsis, Apostolos; Underwood, Thomas E.J.

    2005-12-01

    We study minimal scenarios of resonant leptogenesis near the electroweak phase transition. These models offer a number of testable phenomenological signatures for low-energy experiments and future high-energy colliders. Our study extends previous analyses of the relevant network of Boltzmann equations, consistently taking into account effects from out of equilibrium sphalerons and single lepton flavors. We show that the effects from single lepton flavors become very important in variants of resonant leptogenesis, where the observed baryon asymmetry in the Universe is created by lepton-to-baryon conversion of an individual lepton number, for example, that of the {tau}-lepton. The predictions of such resonant {tau}-leptogenesis models for the final baryon asymmetry are almost independent of the initial lepton-number and heavy neutrino abundances. These models accommodate the current neutrino data and have a number of testable phenomenological implications. They contain electroweak-scale heavy Majorana neutrinos with appreciable couplings to electrons and muons, which can be probed at future e{sup +}e{sup -} and {mu}{sup +}{mu}{sup -} high-energy colliders. In particular, resonant {tau}-leptogenesis models predict sizable 0{nu}{beta}{beta} decay, as well as e- and {mu}-number-violating processes, such as {mu}{yields}e{gamma} and {mu}{yields}e conversion in nuclei, with rates that are within reach of the experiments proposed by the MEG and MECO collaborations.

  16. Notes on Experiments.

    ERIC Educational Resources Information Center

    Physics Education, 1988

    1988-01-01

    Describes four physics experiments including "Investigation of Box Resonances Using a Micro"; "A Direct Reading Wattmeter, DC or AC"; "Exercises in the Application of Ohm's Law"; and "Hysteresis on Gas Discharges." Discusses procedures, instrumentation, and analysis in each example. (CW)

  17. 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.

  18. 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 the NMR spectrum changes either due to an incommensurate magnetic order or due to spin reorientation. In summary the work presented in this thesis focusses on the NMR investigation of the magnetic properties of various compounds frustrated by the competing exchange interactions. References. [1] A. Yogi, N. Ahmad, R. Nath, A. A. Tsirlin, J. Sichelschmidt, B. Roy and Y. Furukawa, arXiv:1409.3076 (submitted to Phys. Rev. B). [2] Beas Roy, Yuji Furukawa, Ramesh Nath, David C. Johnston, J. Phys.: Conf. Ser. 320, 012048 (2011). [3] Beas Roy, Yuji Furukawa, David Johnston, Ramesh Nath, Yasuhiro Komaki, Hideto Fukazawa, and Yoh Kohori, ``Magnetic phase diagram of the two-dimensional frustrated square lattice compound BaCdVO(PO4)2 from high-pressure and low-temperature 31P-NMR study'', Paper to be submitted. [4] S. Ran, S. L. Bud'ko, D. K. Pratt, A. Kreyssig, M. G. Kim, M. J. Kramer, D. H. Ryan, W. N. Rowan-Weetaluktuk, Y. Furukawa, B. Roy, A. I. Goldman, and P. C. Canfield, Phys. Rev. B 83, 144517 (2011). [5] Y. Furukawa, B. Roy, S. Ran, S. L. Bud'ko and P. C. Canfield, Phys. Rev. B 89, 121109 (R) (2014). [6] B. Roy, Abhishek Pandey, Q. Zhang, T. W. Heitmann, D. Vaknin, D. C. Johnston, and Y. Furukawa, Phys. Rev. B 88, 174415 (2013). [7] R. Nath, K. M. Ranjith, B. Roy, D. C. Johnston, Y. Furukawa, and A. A. Tsirlin, Phys. Rev. B 90, 024431 (2014).

  19. Hadronic Resonances from Lattice QCD

    SciTech Connect

    Lichtl, Adam C.; Bulava, John; Morningstar, Colin; Edwards, Robert; Mathur, Nilmani; Richards, David; Fleming, George; Juge, K. Jimmy; Wallace, Stephen J.

    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.

  20. Hadronic Resonances from Lattice QCD

    SciTech Connect

    John Bulava; Robert Edwards; George Fleming; K. Jimmy Juge; Adam C. Lichtl; Nilmani Mathur; Colin Morningstar; David Richards; Stephen J. Wallace

    2007-06-16

    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.

  1. Nanomechanical resonance detector

    DOEpatents

    Grossman, Jeffrey C; Zettl, Alexander K

    2013-10-29

    An embodiment of a nanomechanical frequency detector includes a support structure and a plurality of elongated nanostructures coupled to the support structure. Each of the elongated nanostructures has a particular resonant frequency. The plurality of elongated nanostructures has a range of resonant frequencies. An embodiment of a method of identifying an object includes introducing the object to the nanomechanical resonance detector. A resonant response by at least one of the elongated nanostructures of the nanomechanical resonance detector indicates a vibrational mode of the object. An embodiment of a method of identifying a molecular species of the present invention includes introducing the molecular species to the nanomechanical resonance detector. A resonant response by at least one of the elongated nanostructures of the nanomechanical resonance detector indicates a vibrational mode of the molecular species.

  2. Composite arrays of superconducting microstrip line resonators

    SciTech Connect

    Mohebbi, H. R. Miao, G. X.; Benningshof, O. W. B.; Taminiau, I. A. J.; Cory, D. G.

    2014-03-07

    A novel design of an array of half-wave superconductive microstrip resonators is described. The resonator is intended to be useful for electron spin resonance studies of thin film samples at cryogenic temperatures. It achieves a high quality factor, has a small mode-volume, and creates a uniform magnetic field in a plane above the resonator. The device is made of thin film Niobium on sapphire wafer and is tested with a static magnetic field. Variation of Q-factor versus the magnetic field's strength at different temperatures is reported and is in a good agreement with simulation when the loss due to the vortices is included. Also, the power-dependence response of the resonator is shown in experiments and is verified by capturing the nonlinearity associated with the surface impedance of the superconducting film into the circuit model of the device.

  3. Quantum interference between resonant and nonresonant photorecombination

    NASA Astrophysics Data System (ADS)

    Tu, B.; Xiao, J.; Yao, K.; Shen, Y.; Yang, Y.; Lu, D.; Li, W. X.; Qiu, M. L.; Wang, X.; Chen, C. Y.; Fu, Y.; Wei, B.; Zheng, C.; Huang, L. Y.; Zhang, B. H.; Tang, Y. J.; Hutton, R.; Zou, Y.

    2016-03-01

    In this paper, we present experimental and theoretical studies on the interference between resonant and nonresonant photorecombinations for the main resonances of ground-state He-, Be-, B-, C-, N-, and O-like W ions. Experiments were done using a fast electron energy scanning technique at the upgraded Shanghai electron-beam ion trap. Asymmetric resonances were observed, and their Fano factors, which measure the interference degree, were determined. The calculations were done under the framework of Fano's theory by using the flexible atomic code, in which the relativistic configuration interaction method was employed. Among the nine resonances studied in this work, eight experimental results agree with the calculation within experimental uncertainties. But the experimental result for the resonance of Be-like W ions, through the intermediate state of [(1s2s22p 1 /2) 12 p3 /2] 5 /2, deviates from its corresponding theoretical result by 1.3 times experimental uncertainty.

  4. Nonlinear induction detection of electron spin resonance

    NASA Astrophysics Data System (ADS)

    Bachar, Gil; Suchoi, Oren; Shtempluck, Oleg; Blank, Aharon; Buks, Eyal

    2012-07-01

    We present an approach to the induction detection of electron spin resonance (ESR) signals exploiting the nonlinear properties of a superconducting resonator. Our experiments employ a yttrium barium copper oxide superconducting stripline microwave (MW) resonator integrated with a microbridge. A strong nonlinear response of the resonator is thermally activated in the microbridge when exceeding a threshold in the injected MW power. The responsivity factor characterizing the ESR-induced change in the system's output signal is about 100 times larger when operating the resonator near the instability threshold, compared to the value obtained in the linear regime of operation. Preliminary experimental results, together with a theoretical model of this phenomenon are presented. Under appropriate conditions, nonlinear induction detection of ESR can potentially improve upon the current capabilities of conventional linear induction detection ESR.

  5. Integral data analysis for resonance parameters determination

    SciTech Connect

    Larson, N.M.; Leal, L.C.; Derrien, H.

    1997-09-01

    Neutron time-of-flight experiments have long been used to determine resonance parameters. Those resonance parameters have then been used in calculations of integral quantities such as Maxwellian averages or resonance integrals, and results of those calculations in turn have been used as a criterion for acceptability of the resonance analysis. However, the calculations were inadequate because covariances on the parameter values were not included in the calculations. In this report an effort to correct for that deficiency is documented: (1) the R-matrix analysis code SAMMY has been modified to include integral quantities of importance, (2) directly within the resonance parameter analysis, and (3) to determine the best fit to both differential (microscopic) and integral (macroscopic) data simultaneously. This modification was implemented because it is expected to have an impact on the intermediate-energy range that is important for criticality safety applications.

  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. An Inexpensive Resonance Demonstration

    ERIC Educational Resources Information Center

    Dukes, Phillip

    2005-01-01

    The phenomenon of resonance is applicable to almost every branch of physics. Without resonance, there wouldn't be televisions or stereos, or even swings on the playground. However, resonance also has undesirable side effects such as irritating noises in the car and the catastrophic events such as helicopters flying apart. In this article, the…

  8. An Inexpensive Resonance Demonstration

    ERIC Educational Resources Information Center

    Dukes, Phillip

    2005-01-01

    The phenomenon of resonance is applicable to almost every branch of physics. Without resonance, there wouldn't be televisions or stereos, or even swings on the playground. However, resonance also has undesirable side effects such as irritating noises in the car and the catastrophic events such as helicopters flying apart. In this article, the

  9. Mechanical Resonance of a Plastic Strip.

    ERIC Educational Resources Information Center

    Ayers, R. Dean

    1981-01-01

    Presents an experiment to illustrate mechanical resonance designed for use in lower division laboratories. The apparatus and procedure have been kept simple. The basic experiment yields measurements of amplitude versus driving frequency, but a fairly simple elaboration allows for measurements of phase lag as well. (Author/SK)

  10. Unstable resonators with excited converging wave

    NASA Astrophysics Data System (ADS)

    Hodgson, N.; Weber, H.

    1990-04-01

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

  11. Unstable resonators with excited converging wave

    SciTech Connect

    Hodgson, N. ); Weber, H. )

    1990-04-01

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

  12. Resonant and non-resonant magnetic scattering

    SciTech Connect

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

    1991-12-31

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

  13. Resonant and non-resonant magnetic scattering

    SciTech Connect

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

    1991-01-01

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

  14. Alpha resonant scattering for astrophysical reaction studies

    SciTech Connect

    Yamaguchi, H.; Kahl, D.; Nakao, T.; Wakabayashi, Y.; Kubano, S.; Hashimoto, T.; Hayakawa, S.; Kawabata, T.; Iwasa, N.; Teranishi, T.; Kwon, Y. K.; Binh, D. N.; Khiem, L. H.; Duy, N. G.

    2014-05-02

    Several alpha-induced astrophysical reactions have been studied at CRIB (CNS Radioactive Ion Beam separator), which is a low-energy RI beam separator at Center for Nuclear Study (CNS) of the University of Tokyo. One of the methods to study them is the α resonant scattering using the thick-target method in inverse kinematics. Among the recent studies at CRIB, the measurement of {sup 7}Be+α resonant scattering is discussed. Based on the result of the experiment, we evaluated the contributions of high-lying resonances for the {sup 7}Be(α,γ) reaction, and proposed a new cluster band in {sup 11}C.

  15. Resonant 2-photon-ionization of Xe

    SciTech Connect

    Meyer, M.; Lacoursiere, J.; Nahon, L.; Gisselbrecht, M.; Morin, P.; Larzilliere, M.

    1997-01-15

    The combination of laser and synchrotron radiation has been used to investigate in a pump-probe arrangement the ionization of Xe atoms via the resonant state Xe*5p{sup 5}5d[3/2]{sub 1}. In a first type of experiments the synchronization between the pulses of a mode-locked Ar{sup +} laser and the synchrotron radiation has been demonstrated by measuring the lifetime of the intermediate, resonantly excited states. In addition, a tuneable dye laser has been used to excite the Xe*5p{sup 5}4f[5/2]{sub 2} autoionization resonance.

  16. Ovenized microelectromechanical system (MEMS) resonator

    SciTech Connect

    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.

  17. N+CPT clock resonance

    SciTech Connect

    Crescimanno, M.; Hohensee, M.

    2008-12-15

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

  18. Magnetic resonance energy and topological resonance energy.

    PubMed

    Aihara, Jun-Ichi

    2016-04-28

    Ring-current diamagnetism of a polycyclic π-system is closely associated with thermodynamic stability due to the individual circuits. Magnetic resonance energy (MRE), derived from the ring-current diamagnetic susceptibility, was explored in conjunction with graph-theoretically defined topological resonance energy (TRE). For many aromatic molecules, MRE is highly correlative with TRE with a correlation coefficient of 0.996. For all π-systems studied, MRE has the same sign as TRE. The only trouble with MRE may be that some antiaromatic and non-alternant species exhibit unusually large MRE-to-TRE ratios. This kind of difficulty can in principle be overcome by prior geometry-optimisation or by changing spin multiplicity. Apart from the semi-empirical resonance-theory resonance energy, MRE is considered as the first aromatic stabilisation energy (ASE) defined without referring to any hypothetical polyene reference. PMID:26878709

  19. Tailored Asymmetry for Enhanced Coupling to WGM Resonators

    NASA Technical Reports Server (NTRS)

    Mohageg, Makan; Maleki, Lute

    2008-01-01

    Coupling of light into and out of whispering- gallery-mode (WGM) optical resonators can be enhanced by designing and fabricating the resonators to have certain non-axisymmetric shapes (see figure). Such WGM resonators also exhibit the same ultrahigh values of the resonance quality factor (Q) as do prior WGM resonators. These WGM resonators are potentially useful as tunable narrow-band optical filters having throughput levels near unity, high-speed optical switches, and low-threshold laser resonators. These WGM resonators could also be used in experiments to investigate coupling between high-Q and chaotic modes within the resonators. For a WGM resonator made of an optically nonlinear material (e.g., lithium niobate) or another material having a high index of refraction, a prism made of a material having a higher index of refraction (e.g., diamond) must be used as part of the coupling optics. For coupling of a beam of light into (or out of) the high-Q resonator modes, the beam must be made to approach (or recede from) the resonator at a critical angle determined by the indices of refraction of the resonator and prism materials. In the case of a lithium niobate/diamond interface, this angle is approximately 22 .

  20. Miniature Sapphire Acoustic Resonator - MSAR

    NASA Technical Reports Server (NTRS)

    Wang, Rabi T.; Tjoelker, Robert L.

    2011-01-01

    A room temperature sapphire acoustics resonator incorporated into an oscillator represents a possible opportunity to improve on quartz ultrastable oscillator (USO) performance, which has been a staple for NASA missions since the inception of spaceflight. Where quartz technology is very mature and shows a performance improvement of perhaps 1 dB/decade, these sapphire acoustic resonators when integrated with matured quartz electronics could achieve a frequency stability improvement of 10 dB or more. As quartz oscillators are an essential element of nearly all types of frequency standards and reference systems, the success of MSAR would advance the development of frequency standards and systems for both groundbased and flight-based projects. Current quartz oscillator technology is limited by quartz mechanical Q. With a possible improvement of more than x 10 Q with sapphire acoustic modes, the stability limit of current quartz oscillators may be improved tenfold, to 10(exp -14) at 1 second. The electromagnetic modes of sapphire that were previously developed at JPL require cryogenic temperatures to achieve the high Q levels needed to achieve this stability level. However sapphire fs acoustic modes, which have not been used before in a high-stability oscillator, indicate the required Q values (as high as Q = 10(exp 8)) may be achieved at room temperature in the kHz range. Even though sapphire is not piezoelectric, such a high Q should allow electrostatic excitation of the acoustic modes with a combination of DC and AC voltages across a small sapphire disk (approximately equal to l mm thick). The first evaluations under this task will test predictions of an estimated input impedance of 10 kilohms at Q = 10(exp 8), and explore the Q values that can be realized in a smaller resonator, which has not been previously tested for acoustic modes. This initial Q measurement and excitation demonstration can be viewed similar to a transducer converting electrical energy to mechanical energy and back. Such an electrostatic tweeter type excitation of a mechanical resonator will be tested at 5 MHz. Finite element calculation will be applied to resonator design for the desired resonator frequency and optimum configuration. The experiment consists of the sapphire resonator sandwiched between parallel electrodes. A DC+AC voltage can be applied to generate a force to act on a sapphire resonator. With the frequency of the AC voltage tuned to the sapphire resonator frequency, a resonant condition occurs and the sapphire Q can be measured with a high-frequency impedance analyzer. To achieve high Q values, many experimental factors such as vacuum seal, gas damping effects, charge buildup on the sapphire surface, heat dissipation, sapphire anchoring, and the sapphire mounting configuration will need attention. The effects of these parameters will be calculated and folded into the resonator design. It is envisioned that the initial test configuration would allow for movable electrodes to check gap spacing dependency and verify the input impedance prediction. Quartz oscillators are key components in nearly all ground- and space-based communication, tracking, and radio science applications. They play a key role as local oscillators for atomic frequency standards and serve as flywheel oscillators or to improve phase noise in high performance frequency and timing distribution systems. With ultra-stable performance from one to three seconds, an Earth-orbit or moon-based MSAR can enhance available performance options for spacecraft due to elimination of atmospheric path degradation.

  1. Electrically connected resonant optical antennas.

    PubMed

    Prangsma, Jord C; Kern, Johannes; Knapp, Alexander G; Grossmann, Swen; Emmerling, Monika; Kamp, Martin; Hecht, Bert

    2012-08-01

    Electrically connected resonant optical antennas hold promise for the realization of highly efficient nanoscale electro-plasmonic devices that rely on a combination of electric fields and local near-field intensity enhancement. Here we demonstrate the feasibility of such a concept by attaching leads to the arms of a two-wire antenna at positions of minimal near-field intensity with negligible influence on the antenna resonance. White-light scattering experiments in accordance with simulations show that the optical tunability of connected antennas is fully retained. Analysis of the electric properties demonstrates that in the antenna gaps direct current (DC) electric fields of 10(8) V/m can consistently be achieved and maintained over extended periods of time without noticeable damage. PMID:22800440

  2. Acoustic Levitator Maintains Resonance

    NASA Technical Reports Server (NTRS)

    Barmatz, M. B.; Gaspar, M. S.

    1986-01-01

    Transducer loading characteristics allow resonance tracked at high temperature. Acoustic-levitation chamber length automatically adjusted to maintain resonance at constant acoustic frequency as temperature changes. Developed for containerless processing of materials at high temperatures, system does not rely on microphones as resonance sensors, since microphones are difficult to fabricate for use at temperatures above 500 degrees C. Instead, system uses acoustic transducer itself as sensor.

  3. 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.

  4. Notes on Experiments.

    ERIC Educational Resources Information Center

    Physics Education, 1985

    1985-01-01

    Describes: (1) two experiments using a laser (resonant cavity for light and pinhole camera effect with a hologram); (2) optical differaction patterns displayed by microcomputer; and (3) automating the Hall effect (with comments on apparatus needed and computer program used); and (4) an elegant experiment in mechanical equilibrium. (JN)

  5. Cyclotron Resonances in Electron Cloud Dynamics

    SciTech Connect

    Celata, C. M.; Furman, Miguel A.; Vay, J.-L.; Ng, J. S.T.; Grote, D. P.; Pivi, M. T. F.; Wang, L. F.

    2009-04-29

    A new set of resonances for electron cloud dynamics in the presence of a magnetic field has been found. For short beam bunch lengths and low magnetic fields where lb<< 2pi c/omega c (with lb = bunch length, omega c = non-relativistic cyclotron frequency) resonances between the bunch frequency and harmonics of the electron cyclotron frequency cause an increase in the electron cloud density in narrow ranges of magnetic field near the resonances. For ILC parameters the increase in the density is up to a factor ~;;3, and the spatial distribution of the electrons is broader near resonances, lacking the well-defined vertical density"stripes" found for non-resonant cases. Simulations with the 2D computer code POSINST, as well as a single-particle tracking code, were used to elucidate the physics of the dynamics. The existence of the resonances has been confirmed in experiments at PEP-II. The resonances are expected to affect the electron cloud dynamics in the fringe fields of conventional lattice magnets and in wigglers, where the magnetic fields are low. Results of the simulations and experimental observations, the reason for the bunch-length dependence, and details of the dynamics are discussed here.

  6. Nonlinear ferromagnetic resonance shift in nanostructures

    NASA Astrophysics Data System (ADS)

    Guo, Feng; Belova, Lyuba; McMichael, Robert

    2014-03-01

    In dynamic magnetic systems, various experiments have shown that the ferromagnetic resonance frequency can shift up or down with increasing driving power in the nonlinear regime. The resonance shift is important in understanding nonlinear physics in nanomagnets and for applications of spin-torque oscillators. Here, we present a systematic study on the sign of the nonlinear coefficient, i.e. the direction of the resonance field/frequency shift. We use ferromagnetic resonance force microscopy (FMRFM) to measure the ferromagnetic resonance of a series of submicron NiFe ellipses with varying aspect ratios. We find the sign of the resonance shift is determined by both the applied field and the anisotropy field. Our measurement and micromagnetic modeling results are in qualitative agreement with a macro-spin analysis developed by Slavin and Tiberkevich. However, both measurement and modeling results exhibit values of the nonlinear coefficient that are more positive (meaning that the resonance tends to shift toward low field direction) than are predicted by the macrospin model. We attribute the difference to the non-uniformity of the precession modes in the ellipses. By analogy with standing spin waves, we show that nonuniform precession tends to increase the nonlinear frequency coefficient through a magnetostatic mechanism.

  7. Superconducting coplanar waveguide resonators for low temperature pulsed electron spin resonance spectroscopy

    NASA Astrophysics Data System (ADS)

    Malissa, H.; Schuster, D. I.; Tyryshkin, A. M.; Houck, A. A.; Lyon, S. A.

    2013-02-01

    We discuss the design and implementation of thin film superconducting coplanar waveguide micro-resonators for pulsed electron spin resonance experiments. The performance of the resonators with P doped Si epilayer samples is compared to waveguide resonators under equivalent conditions. The high achievable filling factor even for small sized samples and the relatively high Q-factor result in a sensitivity of 4.5 × 108 spins per shot, which is superior to that of conventional waveguide resonators, in particular to spins close to the sample surface. The peak microwave power is on the order of a few milliwatts, which is compatible with measurements at ultra-low temperatures. We also discuss the effect of the nonuniform microwave magnetic field on the Hahn echo power dependence.

  8. Conductive coupling of split ring resonators: a path to THz metamaterials with ultrasharp resonances.

    PubMed

    Al-Naib, Ibraheem; Hebestreit, Erik; Rockstuhl, Carsten; Lederer, Falk; Christodoulides, Demetrios; Ozaki, Tsuneyuki; Morandotti, Roberto

    2014-05-01

    We report on a novel metamaterial structure that sustains extremely sharp resonances in the terahertz domain. This system involves two conductively coupled split ring resonators that together exhibit a novel resonance, in broad analogy to the antiphase mode of the so-called Huygens coupled pendulum. Even though this resonance is in principle forbidden in each individual symmetric split ring, our experiments show that this new coupled mode can sustain quality factors that are more than one order of magnitude larger than those of conventional split ring arrangements. Because of the universality of the metamaterial response, the design principle we present here can be applied across the entire electromagnetic spectrum and to various metamaterial resonators. PMID:24856698

  9. Conductive Coupling of Split Ring Resonators: A Path to THz Metamaterials with Ultrasharp Resonances

    NASA Astrophysics Data System (ADS)

    Al-Naib, Ibraheem; Hebestreit, Erik; Rockstuhl, Carsten; Lederer, Falk; Christodoulides, Demetrios; Ozaki, Tsuneyuki; Morandotti, Roberto

    2014-05-01

    We report on a novel metamaterial structure that sustains extremely sharp resonances in the terahertz domain. This system involves two conductively coupled split ring resonators that together exhibit a novel resonance, in broad analogy to the antiphase mode of the so-called Huygens coupled pendulum. Even though this resonance is in principle forbidden in each individual symmetric split ring, our experiments show that this new coupled mode can sustain quality factors that are more than one order of magnitude larger than those of conventional split ring arrangements. Because of the universality of the metamaterial response, the design principle we present here can be applied across the entire electromagnetic spectrum and to various metamaterial resonators.

  10. On open electromagnetic resonators: relation between interferometers and resonators

    SciTech Connect

    Manenkov, Aleksandr A; Bykov, Vladimir P; Kuleshov, N V

    2010-05-26

    The physical difference between the concepts 'Fabry-Perot interferometer' and 'open resonator' is discussed. It is shown that the use of the term 'Fabry-Perot resonator' for open laser resonators is incorrect both from the historical viewpoint and from the viewpoint of the physical meaning of the processes occurring in these resonators. (laser beams and resonators)

  11. Subwavelength total acoustic absorption with degenerate resonators

    NASA Astrophysics Data System (ADS)

    Yang, Min; Meng, Chong; Fu, Caixing; Li, Yong; Yang, Zhiyu; Sheng, Ping

    2015-09-01

    We report the experimental realization of perfect sound absorption by sub-wavelength monopole and dipole resonators that exhibit degenerate resonant frequencies. This is achieved through the destructive interference of two resonators' transmission responses, while the matching of their averaged impedances to that of air implies no backscattering, thereby leading to total absorption. Two examples, both using decorated membrane resonators (DMRs) as the basic units, are presented. The first is a flat panel comprising a DMR and a pair of coupled DMRs, while the second one is a ventilated short tube containing a DMR in conjunction with a sidewall DMR backed by a cavity. In both examples, near perfect absorption, up to 99.7%, has been observed with the airborne wavelength up to 1.2 m, which is at least an order of magnitude larger than the composite absorber. Excellent agreement between theory and experiment is obtained.

  12. Stochastic resonance during a polymer translocation process

    NASA Astrophysics Data System (ADS)

    Mondal, Debasish; Muthukumar, Murugappan

    We study the translocation of a flexible polymer in a confined geometry subjected to a time-periodic external drive to explore stochastic resonance. We describe the equilibrium translocation process in terms of a Fokker-Planck description and use a discrete two-state model to describe the effect of the external driving force on the translocation dynamics. We observe that no stochastic resonance is possible if the associated free-energy barrier is purely entropic in nature. The polymer chain experiences a stochastic resonance effect only in presence of an energy threshold in terms of polymer-pore interaction. Once stochastic resonance is feasible, the chain entropy controls the optimal synchronization conditions significantly.

  13. Preliminary thoughts on the Aladdin experiments

    SciTech Connect

    Symon, K.

    1987-11-01

    The author suggests three sets of experiments for comparing tracking results with experimental data on the dynamic aperture in Aladdin. They are: (1) aperture determined by a single dominant resonance; (2) dominance by a group of intersecting resonances; and (3) many non-intersecting resonances. Note that one advantage of the suggested experiments is that one can inject, accelerate, and get set for the experiment, and then excite the driving terms slowly, watching the aperture.

  14. Resonant characteristics and sensitivity dependency on the contact surface in QCM-micropillar-based system of coupled resonator sensors

    NASA Astrophysics Data System (ADS)

    Kashan, M. A. M.; Kalavally, V.; Lee, H. W.; Ramakrishnan, N.

    2016-05-01

    We report the characteristics and sensitivity dependence over the contact surface in coupled resonating sensors (CRSs) made of high aspect ratio resonant micropillars attached to a quartz crystal microbalance (QCM). Through experiments and simulation, we observed that when the pillars of resonant heights were placed in maximum displacement regions the resonance frequency of the QCM increased following the coupled resonance characteristics, as the pillar offered elastic loading to the QCM surface. However, the same pillars when placed in relatively lower displacement regions, in spite of their resonant dimension, offered inertial loading and resulted in a decrease in QCM resonance frequency, as the displacement amplitude was insufficient to couple the vibrations from the QCM to the pillars. Accordingly, we discovered that the coupled resonance characteristics not only depend on the resonant structure dimensions but also on the contact regions in the acoustic device. Further analysis revealed that acoustic pressure at the contact surface also influences the resonance frequency characteristics and sensitivity of the CRS. To demonstrate the significance of the present finding for sensing applications, humidity sensing is considered as the example measurand. When a sensing medium made of resonant SU-8 pillars was placed in a maximum displacement region on a QCM surface, the sensitivity increased by 14 times in comparison to a resonant sensing medium placed in a lower displacement region of a QCM surface.

  15. 35Cl nuclear quadrupolar resonance study of 4,4‧-dichlorobiphenyl sulphone

    NASA Astrophysics Data System (ADS)

    Corberó, J. M.; Wolfenson, A. E.; Pusiol, D. J.; Brunetti, A. H.

    1986-02-01

    Pulsed NQR spectroscopy was used to search for a structural phase transition from a normal to an incommensurate phase and others in 4,4‧-dichlorobiphenyl sulphone. The experimental results show the existence of a structural phase transition to an incommensurate phase at 150 K and another transition to a possible commensurate phase at 110 K.

  16. 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…

  17. 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

  18. 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.

  19. Simultaneous whole body 18F-fluorodeoxyglucose positron emission tomography magnetic resonance imaging for evaluation of pediatric cancer: Preliminary experience and comparison with 18F-fluorodeoxyglucose positron emission tomography computed tomography

    PubMed Central

    Pugmire, Brian S; Guimaraes, Alexander R; Lim, Ruth; Friedmann, Alison M; Huang, Mary; Ebb, David; Weinstein, Howard; Catalano, Onofrio A; Mahmood, Umar; Catana, Ciprian; Gee, Michael S

    2016-01-01

    AIM: To describe our preliminary experience with simultaneous whole body 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography and magnetic resonance imaging (PET-MRI) in the evaluation of pediatric oncology patients. METHODS: This prospective, observational, single-center study was Health Insurance Portability and Accountability Act-compliant, and institutional review board approved. To be eligible, a patient was required to: (1) have a known or suspected cancer diagnosis; (2) be under the care of a pediatric hematologist/oncologist; and (3) be scheduled for clinically indicated 18F-FDG positron emission tomography-computed tomography (PET-CT) examination at our institution. Patients underwent PET-CT followed by PET-MRI on the same day. PET-CT examinations were performed using standard department protocols. PET-MRI studies were acquired with an integrated 3 Tesla PET-MRI scanner using whole body T1 Dixon, T2 HASTE, EPI diffusion-weighted imaging (DWI) and STIR sequences. No additional radiotracer was given for the PET-MRI examination. Both PET-CT and PET-MRI examinations were reviewed by consensus by two study personnel. Test performance characteristics of PET-MRI, for the detection of malignant lesions, including FDG maximum standardized uptake value (SUVmax) and minimum apparent diffusion coefficient (ADCmin), were calculated on a per lesion basis using PET-CT as a reference standard. RESULTS: A total of 10 whole body PET-MRI exams were performed in 7 pediatric oncology patients. The mean patient age was 16.1 years (range 12-19 years) including 6 males and 1 female. A total of 20 malignant and 21 benign lesions were identified on PET-CT. PET-MRI SUVmax had excellent correlation with PET-CT SUVmax for both benign and malignant lesions (R = 0.93). PET-MRI SUVmax > 2.5 had 100% accuracy for discriminating benign from malignant lesions using PET-CT reference. Whole body DWI was also evaluated: the mean ADCmin of malignant lesions (780.2 + 326.6) was significantly lower than that of benign lesions (1246.2 + 417.3; P = 0.0003; Student’s t test). A range of ADCmin thresholds for malignancy were evaluated, from 0.5-1.5 × 10-3 mm2/s. The 1.0 × 10-3 ADCmin threshold performed best compared with PET-CT reference (68.3% accuracy). However, the accuracy of PET-MRI SUVmax was significantly better than ADCmin for detecting malignant lesions compared with PET-CT reference (P < 0.0001; two-tailed McNemar’s test). CONCLUSION: These results suggest a clinical role for simultaneous whole body PET-MRI in evaluating pediatric cancer patients. PMID:27028112

  20. Resonant snubber inverter

    DOEpatents

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

    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.

  1. On nonuniform resonator sensors

    NASA Astrophysics Data System (ADS)

    Caruntu, Dumitru I.; Lozano, Karen; Fuentes, Arturo; Netro, Jesus

    2009-03-01

    Mass deposition influence on natural frequencies of nonuniform cantilever resonator sensors of linear and parabolic thickness is investigated in this paper. Resonator sensitivity, defined as a fraction of change in frequency per deposited mass, is found. Constant thickness mass deposition on all four lateral surfaces of the cantilever of rectangular crosssection was assumed. The Euler-Bernoulli theory was used under the assumption that the beams are slender. Mass deposition on the free end surface of the beams was neglected. The deposition thickness was considered uniform and very small compared to any beam dimension. The deposited mass had no contribution to the stiffness, only to the mass. Results show that when compared to the sensitivity of uniform resonator, the sensitivity of linear thickness resonator and parabolic thickness resonator are in the first mode 6 times and 3 times higher, respectively.

  2. 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.

  3. Micromachined resonant gyroscope

    NASA Astrophysics Data System (ADS)

    Qiu, Anping; Wang, Shourong; Zhou, Bailing

    2003-09-01

    Resonant sensing has a number of advantages, including simpler dynamics and control, improved stability, large dynamic range, high resolution, and a quasidigital FM output. Resonant sensing is attractive in micromachined gyroscope application. In this paper, we present a new micromachined resonant gyroscope and briefly introduce the basic operating principle. The double-ended tuning fork (DETF) is an important element in DETF resonator. A theoretical treatment starting from a classical theory for Bernoulli-Euler beams to modal the operation of DETF is given. T The relation between the frequency shift and the applied force is also built. The simulation and the relation of the frequency shift and the applied force by the finite element analysis (FEA) are presented. The conclusion is that analytical analysis results are very close to the simulation results by FEA. Thus, usefulness of the analytical analysis results may be more efficient for our design of micromachined resonant gyroscopes.

  4. 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.

  5. Electromagnetic decay of giant resonances

    SciTech Connect

    Beene, J.R.; Bertrand, F.E.; Halbert, M.L.; Auble, R.L.; Hensley, D.C.; Horen, D.J.; Robinson, R.L.; Sayer, R.O.; Sjoreen, T.P.

    1985-01-01

    Coincidence experiments were done to investigate the photon and neutron emission from the giant resonance regions of /sup 208/Pb and /sup 90/Zr using the ORNL Spin Spectrometer, a 72-segment NaI detector system. We have determined the total gamma-decay probability, the ground-state gamma branching ratio, and the branching ratios to a number of low-lying states as a function of excitation energy in /sup 208/Pb to approx.15 MeV. Similar data were also obtained on /sup 90/Zr. The total yield of ground-state E2 gamma radiation in /sup 208/Pb and the comparative absence of such radiation in /sup 90/Zr can only be understood if decay of compound (damped) states is considered. Other observations in /sup 208/Pb include the absence of a significant branch from the giant quadrupole resonance (GQR) to the 3/sup -/ state at 2.6 MeV, a strong branch to a 3/sup -/ state at 4.97 MeV from the same region, and transitions to various 1/sup -/ states between 5 to 7 MeV from the E* approx. 14 MeV region (EO resonance).

  6. Magnetic Resonance Study of Nanodiamonds

    NASA Astrophysics Data System (ADS)

    Shames, A. I.; Panich, A. M.; Kempiski, W.; Baidakova, M. V.; Osipov, V. Yu.; Enoki, T.; Vul', A. Ya.

    Magnetic resonance techniques, namely Electron Paramagnetic Resonance (EPR) and solid state Nuclear Magnetic Resonance (NMR), are powerful non-destructive tools for studying electron-nuclear and crystalline structure, inherent electronic and magnetic properties and transformations in carbon-based nanomaterials. EPR allows to control purity of ultradispersed diamond (UDD) samples, to study the origin, location and spin-lattice relaxation of radical-type carbon-inherited paramagnetic centers (RPC) as well as their transformation during the process of temperature driven diamond-to-graphite conversion. Solid state NMR on 1H and 13C nuclei provide one with information on the crystalline quality, allows quantitative estimation of the number of different allotropic forms, and reveals electron-nuclear interactions within the UDD samples under study. Results of recent EPR and 13C NMR study of pure and transition metal doped UDD samples, obtained by detonation technique, are reported and discussed. In addition to characteristic EPR signals, originated form para- and ferromagnetic impurities and doping ions, the UDD samples show a high concentration of RPC (up to 1020 spin/gram), which are due to structural defects (dangling C-C bonds) on the diamond cluster surface. In-situ EPR sample's vacuumization experiment in conjunction with precise SQUID magnetization measurements allowed concluding that each UDD particle carries a single spin (dangling bond) per each from 8 crystal (111) facets bounded the particle.

  7. Observation of Fano resonances in highly doped semiconductors plasmonic resonators (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Taliercio, Thierry; Ntsame Guilengui, Vilianne; Rodriguez, Jean-Baptiste; Cerutti, Laurent; Tournié, Eric

    2015-09-01

    All-semiconductor plasmonics gives the opportunity to build new plasmonic structures with embedded resonators of highly doped semiconductor (HDSC) in a matrix of un-doped semiconductor for mid-IR applications. In this work, we report on the excitation of Fano resonances in the mid-infrared range using plasmonic resonators based on HDSC. Using adequate semiconductors, InAsSb and GaSb grown by molecular beam epitaxy (MBE), we have designed the right structure to obtain the expected optical properties. The samples are lattice matched to the GaSb substrate which offers the possibility to integrate the plasmonic resonators at the heart of photonic devices. The embedded nanostructures have been studied by high-resolution transmission electron-microscopy (HR-TEM) to accurately retrieve the geometrical parameters of the resonator. These actual geometrical parameters have then been used to model the optical properties of the HDSC resonators by the FDTD technique and a model based on Fano resonances. Excellent agreement has been achieved between simulation and experiments. We show that it is possible to control the optical properties of the plasmonic resonators by adjusting their geometrical parameters or the doping level of the HDSC. This work demonstrates the possibility to develop all-semiconductor plasmonics for photonic applications in the mid-IR range.

  8. 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

  9. Electrodynamics of a ring-shaped spiral resonator

    SciTech Connect

    Maleeva, N.; Karpov, A.; Averkin, A.; Fistul, M. V.; Zhuravel, A. P.; Jung, P.; Ustinov, A. V.

    2014-02-14

    We present analytical, numerical, and experimental investigations of electromagnetic resonant modes of a compact monofilar Archimedean spiral resonator shaped in a ring, with no central part. Planar spiral resonators are interesting as components of metamaterials for their compact deep-subwavelength size. Such resonators couple primarily to the magnetic field component of the incident electromagnetic wave, offering properties suitable for magnetic meta-atoms. Surprisingly, the relative frequencies of the resonant modes follow the sequence of the odd numbers as f{sub 1}:f{sub 2}:f{sub 3}:f{sub 4}… = 1:3:5:7…, despite the nearly identical boundary conditions for electromagnetic fields at the extremities of the resonator. In order to explain the observed spectrum of resonant modes, we show that the current distribution inside the spiral satisfies a particular Carleman type singular integral equation. By solving this equation, we obtain a set of resonant frequencies. The analytically calculated resonance frequencies and the current distributions are in good agreement with experimental data and the results of numerical simulations. By using low-temperature laser scanning microscopy of a superconducting spiral resonator, we compare the experimentally visualized ac current distributions over the spiral with the calculated ones. Theory and experiment agree well with each other. Our analytical model allows for calculation of a detailed three-dimensional magnetic field structure of the resonators.

  10. Seeing, Acting, Understanding: Motor Resonance in Language Comprehension

    ERIC Educational Resources Information Center

    Zwaan, Rolf A.; Taylor, Lawrence J.

    2006-01-01

    Observing actions and understanding sentences about actions activates corresponding motor processes in the observer-comprehender. In 5 experiments, the authors addressed 2 novel questions regarding language-based motor resonance. The 1st question asks whether visual motion that is associated with an action produces motor resonance in sentence…

  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. Modelling resonant planetary systems

    NASA Astrophysics Data System (ADS)

    Emel'yanenko, V.

    2012-09-01

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

  13. Spin resonance strength calculations

    SciTech Connect

    Courant,E.D.

    2008-10-06

    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.

  14. Tunable multiwalled nanotube resonator

    DOEpatents

    Zettl, Alex K.; Jensen, Kenneth J.; Girit, Caglar; Mickelson, William E.; Grossman, Jeffrey C.

    2011-03-29

    A tunable nanoscale resonator has potential applications in precise mass, force, position, and frequency measurement. One embodiment of this device consists of a specially prepared multiwalled carbon nanotube (MWNT) suspended between a metal electrode and a mobile, piezoelectrically controlled contact. By harnessing a unique telescoping ability of MWNTs, one may controllably slide an inner nanotube core from its outer nanotube casing, effectively changing its length and thereby changing the tuning of its resonance frequency. Resonant energy transfer may be used with a nanoresonator to detect molecules at a specific target oscillation frequency, without the use of a chemical label, to provide label-free chemical species detection.

  15. Tunable multiwalled nanotube resonator

    DOEpatents

    Jensen, Kenneth J; Girit, Caglar O; Mickelson, William E; Zettl, Alexander K; Grossman, Jeffrey C

    2013-11-05

    A tunable nanoscale resonator has potential applications in precise mass, force, position, and frequency measurement. One embodiment of this device consists of a specially prepared multiwalled carbon nanotube (MWNT) suspended between a metal electrode and a mobile, piezoelectrically controlled contact. By harnessing a unique telescoping ability of MWNTs, one may controllably slide an inner nanotube core from its outer nanotube casing, effectively changing its length and thereby changing the tuning of its resonance frequency. Resonant energy transfer may be used with a nanoresonator to detect molecules at a specific target oscillation frequency, without the use of a chemical label, to provide label-free chemical species detection.

  16. Invited Paper Optical Resonators For Associative Memory

    NASA Astrophysics Data System (ADS)

    Anderson, Dana Z.

    1986-06-01

    One can construct a memory having associative characteristics using optical resonators with an internal gain medium. The device operates on the principle that an optical resonator employing a holographic grating can have user prescribed eigenmodes. Information that is to be recalled is contained in the hologram. Each information entity (e.g. an image of a cat) defines an eigenmode of the resonator. The stored information is accessed by injecting partial information (e.g. an image of the cat's ear) into the resonator. The appropriate eigenmode is selected through a competitive process in a gain medium placed inside the resonator. With a net gain greater than one, the gain amplifies the field belonging to the eigenmode that most resembles the injected field; the other eigenmodes are suppressed via the competition for the gain. One can expect this device to display several intriguing features such as recall transitions and creativity. I will discuss some of the general properties of this class of devices and present the results from a series of experiments with a simple holographic resonator employing photorefractive gain.

  17. Repeated passing principle for propagation in optical resonators

    NASA Astrophysics Data System (ADS)

    Keča, Tatjana P.; Headley, William R.; Mashanovich, Goran Z.; Matavulj, Petar S.

    2016-04-01

    In this paper we make comparison between a well-known theoretical model of light propagation through racetrack resonator and experimentally obtained results. Observed differences are studied and some original modifications are made in the existing model so as to achieve better alignment with experiment. The influence of several geometric parameters on racetrack's response is used for further adjustments to be performed. This procedure opens up the possibility to estimate the free spectral range and resonant wavelength for different geometric parameters and consequently to predict resonator functionality and working conditions, as well as functionality of complex photonic devices based on resonant structures.

  18. Neutron Resonance Spin Determination Using Multi-Segmented Detector DANCE

    NASA Astrophysics Data System (ADS)

    Baramsai, B.; Mitchell, G. E.; Agvaanluvsan, U.; Becvar, F.; Bredeweg, T. A.; Couture, A.; Chyzh, A.; Dashdorj, D.; Haight, R. C.; Jandel, M.; Keksis, A. L.; Krticka, M.; O'Donnell, J. M.; Rundberg, R. S.; Ullmann, J. L.; Vieira, D. J.; Walker, C.; Wouters, J. M.

    2011-06-01

    A sensitive method to determine the spin of neutron resonances is introduced based on the statistical pattern recognition technique. The new method was used to assign the spins of s-wave resonances in 155Gd. The experimental neutron capture data for these nuclei were measured with the DANCE (Detector for Advanced Neutron Capture Experiment) calorimeter at the Los Alamos Neutron Science Center. The highly segmented calorimeter provided detailed multiplicity distributions of the capture ?-rays. Using this information, the spins of the neutron capture resonances were determined. With these new spin assignments, level spacings are determined separately for s-wave resonances with J? = 1- and 2-.

  19. Tunable whispering-gallery-mode resonators for cavity quantum electrodynamics

    SciTech Connect

    Louyer, Y.; Meschede, D.; Rauschenbeutel, A.

    2005-09-15

    We theoretically study the properties of highly prolate-shaped dielectric microresonators. Such resonators sustain whispering-gallery modes that exhibit two spatially well-separated regions with enhanced field strength. The field per photon on the resonator surface is significantly higher than, e.g., for equatorial whispering-gallery modes in microsphere resonators with a comparable mode volume. At the same time, the frequency spacing of these modes is much more favorable, so that a tuning range of several free spectral ranges should be attainable. We discuss the possible application of such resonators for cavity quantum electrodynamics experiments with neutral atoms and reveal distinct advantages with respect to existing concepts.

  20. Resonant quantum transitions in trapped antihydrogen atoms.

    PubMed

    Amole, C; Ashkezari, M D; Baquero-Ruiz, M; Bertsche, W; Bowe, P D; Butler, E; Capra, A; Cesar, C L; Charlton, M; Deller, A; Donnan, P H; Eriksson, S; Fajans, J; Friesen, T; Fujiwara, M C; Gill, D R; Gutierrez, A; Hangst, J S; Hardy, W N; Hayden, M E; Humphries, A J; Isaac, C A; Jonsell, S; Kurchaninov, L; Little, A; Madsen, N; McKenna, J T K; Menary, S; Napoli, S C; Nolan, P; Olchanski, K; Olin, A; Pusa, P; Rasmussen, C Ø; Robicheaux, F; Sarid, E; Shields, C R; Silveira, D M; Stracka, S; So, C; Thompson, R I; van der Werf, D P; Wurtele, J S

    2012-03-22

    The hydrogen atom is one of the most important and influential model systems in modern physics. Attempts to understand its spectrum are inextricably linked to the early history and development of quantum mechanics. The hydrogen atom's stature lies in its simplicity and in the accuracy with which its spectrum can be measured and compared to theory. Today its spectrum remains a valuable tool for determining the values of fundamental constants and for challenging the limits of modern physics, including the validity of quantum electrodynamics and--by comparison with measurements on its antimatter counterpart, antihydrogen--the validity of CPT (charge conjugation, parity and time reversal) symmetry. Here we report spectroscopy of a pure antimatter atom, demonstrating resonant quantum transitions in antihydrogen. We have manipulated the internal spin state of antihydrogen atoms so as to induce magnetic resonance transitions between hyperfine levels of the positronic ground state. We used resonant microwave radiation to flip the spin of the positron in antihydrogen atoms that were magnetically trapped in the ALPHA apparatus. The spin flip causes trapped anti-atoms to be ejected from the trap. We look for evidence of resonant interaction by comparing the survival rate of trapped atoms irradiated with microwaves on-resonance to that of atoms subjected to microwaves that are off-resonance. In one variant of the experiment, we detect 23 atoms that survive in 110 trapping attempts with microwaves off-resonance (0.21 per attempt), and only two atoms that survive in 103 attempts with microwaves on-resonance (0.02 per attempt). We also describe the direct detection of the annihilation of antihydrogen atoms ejected by the microwaves. PMID:22398451

  1. Micro-machined resonator

    DOEpatents

    Godshall, Ned A.; Koehler, Dale R.; Liang, Alan Y.; Smith, Bradley K.

    1993-01-01

    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.

  2. 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.

  3. Resonant ultrasound spectroscopy

    DOEpatents

    Migliori, Albert

    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.

  4. Resonances in QCD

    NASA Astrophysics Data System (ADS)

    Lutz, Matthias F. M.; Lange, Jens Sören; Pennington, Michael; Bettoni, Diego; Brambilla, Nora; Crede, Volker; Eidelman, Simon; Gillitzer, Albrecht; Gradl, Wolfgang; Lang, Christian B.; Metag, Volker; Nakano, Takashi; Nieves, Juan; Neubert, Sebastian; Oka, Makoto; Olsen, Stephen L.; Pappagallo, Marco; Paul, Stephan; Pelizäus, Marc; Pilloni, Alessandro; Prencipe, Elisabetta; Ritman, Jim; Ryan, Sinead; Thoma, Ulrike; Uwer, Ulrich; Weise, Wolfram

    2016-04-01

    We report on the EMMI Rapid Reaction Task Force meeting 'Resonances in QCD', which took place at GSI October 12-14, 2015. A group of 26 people met to discuss the physics of resonances in QCD. The aim of the meeting was defined by the following three key questions: What is needed to understand the physics of resonances in QCD? Where does QCD lead us to expect resonances with exotic quantum numbers? What experimental efforts are required to arrive at a coherent picture? For light mesons and baryons only those with up, down and strange quark content were considered. For heavy-light and heavy-heavy meson systems, those with charm quarks were the focus. This document summarizes the discussions by the participants, which in turn led to the coherent conclusions we present here.

  5. Microwave Oscillators Based on Nonlinear WGM Resonators

    NASA Technical Reports Server (NTRS)

    Maleki, Lute; Matsko, Andrey; Savchenkov, Anatoliy; Strekalov, Dmitry

    2006-01-01

    Optical oscillators that exploit resonantly enhanced four-wave mixing in nonlinear whispering-gallery-mode (WGM) resonators are under investigation for potential utility as low-power, ultra-miniature sources of stable, spectrally pure microwave signals. There are numerous potential uses for such oscillators in radar systems, communication systems, and scientific instrumentation. The resonator in an oscillator of this type is made of a crystalline material that exhibits cubic Kerr nonlinearity, which supports the four-photon parametric process also known as four-wave mixing. The oscillator can be characterized as all-optical in the sense that the entire process of generation of the microwave signal takes place within the WGM resonator. The resonantly enhanced four-wave mixing yields coherent, phase-modulated optical signals at frequencies governed by the resonator structure. The frequency of the phase-modulation signal, which is in the microwave range, equals the difference between the frequencies of the optical signals; hence, this frequency is also governed by the resonator structure. Hence, further, the microwave signal is stable and can be used as a reference signal. The figure schematically depicts the apparatus used in a proof-of-principle experiment. Linearly polarized pump light was generated by an yttrium aluminum garnet laser at a wavelength of 1.32 microns. By use of a 90:10 fiber-optic splitter and optical fibers, some of the laser light was sent into a delay line and some was transmitted to one face of glass coupling prism, that, in turn, coupled the laser light into a crystalline CaF2 WGM disk resonator that had a resonance quality factor (Q) of 6x10(exp 9). The output light of the resonator was collected via another face of the coupling prism and a single-mode optical fiber, which transmitted the light to a 50:50 fiber-optic splitter. One output of this splitter was sent to a slow photodiode to obtain a DC signal for locking the laser to a particular resonator mode. The other output of this splitter was combined with the delayed laser signal in another 50:50 fiber-optic splitter used as a combiner. The output.of the combiner was fed to a fast photodiode that demodulated light and generated microwave signal. In this optical configuration, the resonator was incorporated into one arm of a Mach-Zehnder interferometer, which was necessary for the following reasons: It was found that when the output of the resonator was sent directly to a fast photodiode, the output of the photodiode did not include a measurable microwave signal. However, when the resonator was placed in an arm of the interferometer and the delay in the other arm was set at the correct value, the microwave signal appeared. Such behavior is distinctly characteristic of phase-modulated light. The phase-modulation signal had a frequency of about 8 GHz, corresponding to the free spectral range of the resonator. The spectral width of this microwave signal was less than 200 Hz. The threshold pump power for generating the microwave signal was about 1 mW. It would be possible to reduce the threshold power by several orders of magnitude if resonators could be made from crystalline materials in dimensions comparable to those of micro-resonators heretofore made from fused silica.

  6. Cylindrical laser resonator

    DOEpatents

    Casperson, Lee W.

    1976-02-24

    The properties of an improved class of lasers is presented. In one configuration of these lasers the radiation propagates radially within the amplifying medium, resulting in high fields and symmetric illumination at the resonator axis. Thus there is a strong focusing of energy at the axis of the resonator. In a second configuration the radiation propagates back and forth in a tubular region of space.

  7. Injector with integrated resonator

    SciTech Connect

    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.

  8. 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.

  9. Hexagonal quartz resonator

    DOEpatents

    Peters, Roswell D. M.

    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.

  10. 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.

  11. Anomalous Diffusion Near Resonances

    SciTech Connect

    Sen, Tanaji; /Fermilab

    2010-05-01

    Synchro-betatron resonances can lead to emittance growth and the loss of luminosity. We consider the detailed dynamics of a bunch near such a low order resonance driven by crossing angles at the collision points. We characterize the nature of diffusion and find that it is anomalous and sub-diffusive. This affects both the shape of the beam distribution and the time scales for growth. Predictions of a simplified anomalous diffusion model are compared with direct simulations. Transport of particles near resonances is still not a well understood phenomenon. Often, without justification, phase space motion is assumed to be a normal diffusion process although at least one case of anomalous diffusion in beam dynamics has been reported [1]. Here we will focus on the motion near synchro-betatron resonances which can be excited by several means, including beams crossing at an angle at the collision points as in the LHC. We will consider low order resonances which couple the horizontal and longitudinal planes, both for simplicity and to observe large effects over short time scales. While the tunes we consider are not practical for a collider, nonetheless the transport mechanisms we uncover are also likely to operate at higher order resonances.

  12. Resonantly driven wobbling kinks.

    PubMed

    Oxtoby, O F; Barashenkov, I V

    2009-08-01

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

  13. Plasmofluidic Disk Resonators.

    PubMed

    Kwon, Min-Suk; Ku, Bonwoo; Kim, Yonghan

    2016-01-01

    Waveguide-coupled silicon ring or disk resonators have been used for optical signal processing and sensing. Large-scale integration of optical devices demands continuous reduction in their footprints, and ultimately they need to be replaced by silicon-based plasmonic resonators. However, few waveguide-coupled silicon-based plasmonic resonators have been realized until now. Moreover, fluid cannot interact effectively with them since their resonance modes are strongly confined in solid regions. To solve this problem, this paper reports realized plasmofluidic disk resonators (PDRs). The PDR consists of a submicrometer radius silicon disk and metal laterally surrounding the disk with a 30-nm-wide channel in between. The channel is filled with fluid, and the resonance mode of the PDR is strongly confined in the fluid. The PDR coupled to a metal-insulator-silicon-insulator-metal waveguide is implemented by using standard complementary metal oxide semiconductor technology. If the refractive index of the fluid increases by 0.141, the transmission spectrum of the waveguide coupled to the PDR of radius 0.9 μm red-shifts by 30 nm. The PDR can be used as a refractive index sensor requiring a very small amount of analyte. Plus, the PDR filled with liquid crystal may be an ultracompact intensity modulator which is effectively controlled by small driving voltage. PMID:26979929

  14. Resonant nonlinear ultrasound spectroscopy

    DOEpatents

    Johnson, Paul A.; TenCate, James A.; Guyer, Robert A.; Van Den Abeele, Koen E. A.

    2001-01-01

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

  15. Plasmofluidic Disk Resonators

    NASA Astrophysics Data System (ADS)

    Kwon, Min-Suk; Ku, Bonwoo; Kim, Yonghan

    2016-03-01

    Waveguide-coupled silicon ring or disk resonators have been used for optical signal processing and sensing. Large-scale integration of optical devices demands continuous reduction in their footprints, and ultimately they need to be replaced by silicon-based plasmonic resonators. However, few waveguide-coupled silicon-based plasmonic resonators have been realized until now. Moreover, fluid cannot interact effectively with them since their resonance modes are strongly confined in solid regions. To solve this problem, this paper reports realized plasmofluidic disk resonators (PDRs). The PDR consists of a submicrometer radius silicon disk and metal laterally surrounding the disk with a 30-nm-wide channel in between. The channel is filled with fluid, and the resonance mode of the PDR is strongly confined in the fluid. The PDR coupled to a metal-insulator-silicon-insulator-metal waveguide is implemented by using standard complementary metal oxide semiconductor technology. If the refractive index of the fluid increases by 0.141, the transmission spectrum of the waveguide coupled to the PDR of radius 0.9 μm red-shifts by 30 nm. The PDR can be used as a refractive index sensor requiring a very small amount of analyte. Plus, the PDR filled with liquid crystal may be an ultracompact intensity modulator which is effectively controlled by small driving voltage.

  16. Plasmofluidic Disk Resonators

    PubMed Central

    Kwon, Min-Suk; Ku, Bonwoo; Kim, Yonghan

    2016-01-01

    Waveguide-coupled silicon ring or disk resonators have been used for optical signal processing and sensing. Large-scale integration of optical devices demands continuous reduction in their footprints, and ultimately they need to be replaced by silicon-based plasmonic resonators. However, few waveguide-coupled silicon-based plasmonic resonators have been realized until now. Moreover, fluid cannot interact effectively with them since their resonance modes are strongly confined in solid regions. To solve this problem, this paper reports realized plasmofluidic disk resonators (PDRs). The PDR consists of a submicrometer radius silicon disk and metal laterally surrounding the disk with a 30-nm-wide channel in between. The channel is filled with fluid, and the resonance mode of the PDR is strongly confined in the fluid. The PDR coupled to a metal-insulator-silicon-insulator-metal waveguide is implemented by using standard complementary metal oxide semiconductor technology. If the refractive index of the fluid increases by 0.141, the transmission spectrum of the waveguide coupled to the PDR of radius 0.9 μm red-shifts by 30 nm. The PDR can be used as a refractive index sensor requiring a very small amount of analyte. Plus, the PDR filled with liquid crystal may be an ultracompact intensity modulator which is effectively controlled by small driving voltage. PMID:26979929

  17. Whispering modes in anisotropic and isotropic dielectric spherical resonators

    NASA Astrophysics Data System (ADS)

    Le Floch, Jean-Michel; Anstie, James David; Tobar, Michael Edmund; Hartnett, John Gideon; Bourgeois, Pierre-Yves; Cros, Dominique

    2006-11-01

    The properties of degenerate whispering spherical modes within a fused silica and sapphire dielectric resonator have been investigated. However, departure from spherical symmetry occurs due to the support structure and anisotropy of the material. Finite element modeling is used to predicted the lifting of the frequency degeneracy, and is confirmed by experiment. Further optimization of the sapphire resonator to realize a Michelson Morley experiment is discussed.

  18. Conductively coupled resonator scheme for dispersive transparency in metamaterials

    NASA Astrophysics Data System (ADS)

    Turaga, Shuvan Prashant; Wu, Jianfeng; Banas, Agnieszka; Banas, Krzysztof; Bettiol, Andrew A.

    2014-11-01

    We present and demonstrate a new type of single resonator based planar metamaterial exhibiting electromagnetically induced transparency (EIT)-like transmission behavior. The novel design involves physically coupled split-ring resonator (SRR) and a dipolar ring as opposed to many inductively coupled resonators explored in the past. Both experiments and simulations reveal a dispersive transparency due to coupled resonances and the underlying mechanism. Further, the conductive and inductive coupling scenarios for this structure were compared where conductive coupling was found to coerce the direction of light induced currents and stronger in effect than inductive coupling. Resonance tuning is achieved by moving the bar coupling SRR and the ring. Hence, we show that conductive coupling has potential in tailoring coupled resonances of desired quality factor and fabricating metamaterials for enhanced sensing.

  19. Magnetic resonance neurography of the brachial plexus

    PubMed Central

    Upadhyaya, Vaishali; Upadhyaya, Divya Narain; Kumar, Adarsh; Pandey, Ashok Kumar; Gujral, Ratni; Singh, Arun Kumar

    2015-01-01

    Magnetic Resonance Imaging (MRI) is being increasingly recognised all over the world as the imaging modality of choice for brachial plexus and peripheral nerve lesions. Recent refinements in MRI protocols have helped in imaging nerve tissue with greater clarity thereby helping in the identification, localisation and classification of nerve lesions with greater confidence than was possible till now. This article on Magnetic Resonance Neurography (MRN) is based on the authors’ experience of imaging the brachial plexus and peripheral nerves using these protocols over the last several years. PMID:26424974

  20. Roper resonance and the baryon spectrum

    SciTech Connect

    Elsey, J.A.; Afnan, I.R. )

    1989-10-01

    We present a method for calculating the baryon spectrum in the cloudy-bag model in which the masses of the baryons are identical to the poles of the {ital S} matrix in the complex energy plane. In particular, we demonstrate that the width for the decay of these resonances by pion emission is dependent on whether the calculations are carried out on the real energy axis or at the resonance poles, the latter being consistent with the scattering experiments that determine these widths. Results for {ital N}{sup *}(1440) are presented.

  1. Stochastic Resonance in Protein Folding Dynamics.

    PubMed

    Davtyan, Aram; Platkov, Max; Gruebele, Martin; Papoian, Garegin A

    2016-05-01

    Although protein folding reactions are usually studied under static external conditions, it is likely that proteins fold in a locally fluctuating cellular environment in vivo. To mimic such behavior in in vitro experiments, the local temperature of the solvent can be modulated either harmonically or using correlated noise. In this study, coarse-grained molecular simulations are used to investigate these possibilities, and it is found that both periodic and correlated random fluctuations of the environment can indeed accelerate folding kinetics if the characteristic frequencies of the applied fluctuations are commensurate with the internal timescale of the folding reaction; this is consistent with the phenomenon of stochastic resonance observed in many other condensed-matter processes. To test this theoretical prediction, the folding dynamics of phosphoglycerate kinase under harmonic temperature fluctuations are experimentally probed using Förster resonance energy transfer fluorescence measurements. To analyze these experiments, a combination of theoretical approaches is developed, including stochastic simulations of folding kinetics and an analytical mean-field kinetic theory. The experimental observations are consistent with the theoretical predictions of stochastic resonance in phosphoglycerate kinase folding. When combined with an alternative experiment on the protein VlsE using a power spectrum analysis, elaborated in Dave et al., ChemPhysChem 2016, 10.1002/cphc.201501041, the overall data overwhelmingly point to the experimental confirmation of stochastic resonance in protein folding dynamics. PMID:26992148

  2. Experimental realization of extraordinary acoustic transmission using Helmholtz resonators

    SciTech Connect

    Crow, Brian C.; Cullen, Jordan M.; McKenzie, William W.; Koju, Vijay; Robertson, William M.

    2015-02-15

    The phenomenon of extraordinary acoustic transmission through a solid barrier with an embedded Helmholtz resonator (HR) is demonstrated. The Helmholtz resonator consists of an embedded cavity and two necks that protrude, one on each side of the barrier. Extraordinary transmission occurs for a narrow spectral range encompassing the resonant frequency of the Helmholtz resonator. We show that an amplitude transmission of 97.5% is achieved through a resonator whose neck creates an open area of 6.25% of the total barrier area. In addition to the enhanced transmission, we show that there is a smooth, continuous phase transition in the transmitted sound as a function of frequency. The frequency dependent phase transition is used to experimentally realize slow wave propagation for a narrow-band Gaussian wave packet centered at the maximum transmission frequency. The use of parallel pairs of Helmholtz resonators tuned to different resonant frequencies is experimentally explored as a means of increasing the transmission bandwidth. These experiments show that because of the phase transition, there is always a frequency between the two Helmholtz resonant frequencies at which destructive interference occurs whether the resonances are close or far apart. Finally, we explain how the phase transition associated with Helmholtz-resonator-mediated extraordinary acoustic transmission can be exploited to produce diffractive acoustic components including sub-wavelength thickness acoustic lenses.

  3. Capture probabilities for secondary resonances

    NASA Technical Reports Server (NTRS)

    Malhotra, Renu

    1990-01-01

    A perturbed pendulum model is used to analyze secondary resonances, and it is shown that a self-similarity between secondary and primary resonances exists. Henrard's (1982) theory is used to obtain formulas for the capture probability into secondary resonances. The tidal evolution of Miranda and Umbriel is considered as an example, and significant probabilities of capture into secondary resonances are found.

  4. Artificial Excitation of Schumann Resonance with HAARP

    NASA Astrophysics Data System (ADS)

    Streltsov, A. V.; Chang, C. L.

    2014-12-01

    We report results from the experiment aimed at the artificial excitation of extremely-low-frequency (ELF) electromagnetic waves with frequencies corresponding to the frequency of Schumann resonance (typically, 7.5 - 8.0 Hz frequency range). Electromagnetic waves with these frequencies can form a standing pattern inside the spherical cavity formed by the surface of the earth and the ionosphere. In the experiment the ELF waves were excited by heating the ionosphere with X-mode HF electromagnetic waves generated by the High Frequency Active Auroral Research Program (HAARP) facility in Alaska. The experiment demonstrates that heating of the ionosphere can excite relatively large-amplitude electromagnetic waves with frequencies in the range of the Schumann resonance, when the ionosphere has a strong F-layer and an electric field greater than 5 mV/m is present in the E-region.

  5. Observation of Resonant Behavior in the Energy Velocity of Diffused Light

    SciTech Connect

    Sapienza, R.; Garcia, P. D.; Blanco, A.; Lopez, C.; Bertolotti, J.; Wiersma, D. S.; Martin, M. D.; Vina, L.

    2007-12-07

    In this Letter we demonstrate Mie resonances mediated transport of light in randomly arranged, monodisperse dielectric spheres packed at high filling fractions. By means of both static and dynamic optical experiments we show resonant behavior in the key transport parameters and, in particular, we find that the energy transport velocity, which is lower than the group velocity, also displays a resonant behavior.

  6. Magnetically-excited flexural plate wave resonator

    SciTech Connect

    Martin, S.J.; Butler, M.A.; Spates, J.J.; Schubert, W.K.; Mitchell, M.A.

    1997-08-01

    A flexural plate wave (FPW) resonator was constructed by patterning current lines on a silicon nitride membrane suspended on a rectangular silicon frame. Eigenmodes of the rectangular membrane were excited using Lorentz forces generated between alternating surface currents and a static in-plane magnetic field. The magnetic field strength required for these devices can be achieved with small permanent magnets ({approx} 1 cm{sup 3}). Preferential coupling to a particular membrane mode was achieved by positioning current lines along longitudinal mode antinodes. An equivalent-circuit model was derived that characterizes the input impedance of a one-port device and the transmission response of a two-port device over a range of frequencies near a single membrane resonance. Experiments were performed to characterize the effects of varying magnetic field, ambient gas, gas pressure, and input power. To the authors` knowledge, this is the first experimental demonstration of a resonant FPW device.

  7. Resonant entrainment of a confined pulsed jet

    NASA Technical Reports Server (NTRS)

    Parikh, P. G.; Moffat, R. J.

    1982-01-01

    This paper reports the discovery of a new resonant entrainment phenomenon associated with a confined, pulsed jet flow. It was found that a confined jet, when pulsed at an organ-pipe resonant frequency of the confinement tube, experiences greatly enhanced entrainment and mixing near the exit end of the confinement tube compared to a steady confined jet. The mixing and entrainment rates for the resonantly pulsed confined jet approach, and in some cases slightly exceed, those for an unconfined pulsed jet. Both visual and quantitative evidence of this phenomenon is presented. The new effect should be of considerable interest in ejector and combustor design, both of which benefit from any enhancement in mixing between a primary and a secondary flow

  8. Fabry-Perot resonance of water waves.

    PubMed

    Couston, Louis-Alexandre; Guo, Qiuchen; Chamanzar, Maysamreza; Alam, Mohammad-Reza

    2015-10-01

    We show that significant water wave amplification is obtained in a water resonator consisting of two spatially separated patches of small-amplitude sinusoidal corrugations on an otherwise flat seabed. The corrugations reflect the incident waves according to the so-called Bragg reflection mechanism, and the distance between the two sets controls whether the trapped reflected waves experience constructive or destructive interference within the resonator. The resulting amplification or suppression is enhanced with increasing number of ripples and is most effective for specific resonator lengths and at the Bragg frequency, which is determined by the corrugation period. Our analysis draws on the analogous mechanism that occurs between two partially reflecting mirrors in optics, a phenomenon named after its discoverers Charles Fabry and Alfred Perot. PMID:26565340

  9. Silicon optomechanical crystal resonator at millikelvin temperatures

    NASA Astrophysics Data System (ADS)

    Meenehan, Seán M.; Cohen, Justin D.; Gröblacher, Simon; Hill, Jeff T.; Safavi-Naeini, Amir H.; Aspelmeyer, Markus; Painter, Oskar

    2014-07-01

    Optical measurements of a nanoscale silicon optomechanical crystal cavity with a mechanical resonance frequency of 3.6 GHz are performed at subkelvin temperatures. We infer optical-absorption-induced heating and damping of the mechanical resonator from measurements of phonon occupancy and motional sideband asymmetry. At the lowest probe power and lowest fridge temperature (Tf=10 mK), the localized mechanical resonance is found to couple at a rate of γi/2π=400 Hz (Qm=9×106) to a thermal bath of temperature Tb≈270 mK. These measurements indicate that silicon optomechanical crystals cooled to millikelvin temperatures should be suitable for a variety of experiments involving coherent coupling between photons and phonons at the single quanta level.

  10. Magnetic plasmonic Fano resonance at optical frequency.

    PubMed

    Bao, Yanjun; Hu, Zhijian; Li, Ziwei; Zhu, Xing; Fang, Zheyu

    2015-05-13

    Plasmonic Fano resonances are typically understood and investigated assuming electrical mode hybridization. Here we demonstrate that a purely magnetic plasmon Fano resonance can be realized at optical frequency with Au split ring hexamer nanostructure excited by an azimuthally polarized incident light. Collective magnetic plasmon modes induced by the circular electric field within the hexamer and each of the split ring can be controlled and effectively hybridized by designing the size and orientation of each ring unit. With simulated results reproducing the experiment, our suggested configuration with narrow line-shape magnetic Fano resonance has significant potential applications in low-loss sensing and may serves as suitable elementary building blocks for optical metamaterials. PMID:25594885

  11. The LHC diphoton resonance and dark matter

    NASA Astrophysics Data System (ADS)

    Mambrini, Yann; Arcadi, Giorgio; Djouadi, Abdelhak

    2016-04-01

    A resonance with a mass of approximately 750 GeV has recently been "observed" at the LHC in its diphoton decay. If this state is not simply a statistical fluctuation which will disappear with more data, it could have important implications not only for particle physics but also for cosmology. In this note, we analyze the implications of such a resonance for the dark matter (DM). Assuming a spin-1/2 DM particle, we first verify that indeed the correct relic density can be obtained for a wide range of the particle mass and weak scale coupling, that are compatible with present data. We then show that the combination of near future direct and indirect detection experiments will allow to probe the CP-nature of the mediator resonance, i.e. discriminate whether it is a scalar or a pseudoscalar like particle.

  12. Enhanced terahertz transmission by surface plasmon resonance

    NASA Astrophysics Data System (ADS)

    Wen, Yongzheng; Yang, Jiancheng; Yu, Xiaomei; Zhao, Yuejin; Liu, Xiaohua; Dong, Liquan

    2012-03-01

    The surface plasmon resonance (SPR) between metal and dielectric material has a good enhancement on electromagnetic wave transmission. In this paper, a series of two-dimension (2D) metal gratings and spiral structures with different geometrical size were experimentally tested by Terahertz time-domain spectroscopy (THz-TDS). The experiment results show that the 2D metal gratings have almost 70% increment on terahertz transmission than the pure silicon substrate in the range of 0.2-2.5THz, which indicates a strong coupling in the terahertz range, and the resonance mode shows a blue shift. On the other hand, the influence of different radiation directions was analyzed. It presents that the slightly higher transmission can be achieved when terahertz wave radiate from the front side than the back side. It reveals that surface plasmon resonance can enhance the terahertz transmission efficiently and has potential applications in security imaging, biological analysis and spectroscopy.

  13. 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 (νQ) 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.

  14. Resonant ultrasound spectrometer

    DOEpatents

    Migliori, Albert; Visscher, William M.; Fisk, Zachary

    1990-01-01

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

  15. Mechanical quantum resonators

    NASA Astrophysics Data System (ADS)

    Cleland, A. N.; Geller, M. R.

    2005-09-01

    We describe the design for a solid-state quantum computational architecture based on the integration of GHz-frequency mechanical resonators with Josephson phase qubits, which have the potential for demonstrating a variety of single- and multi-qubit operations critical to quantum computation. The computational qubits are eigenstates of large-area, current-biased Josephson junctions. Two or more qubits are capacitively coupled to a piezoelectric nanoelectromechanical disk resonator, which enables coherent coupling of the qubits. The integrated system is analogous to one or more few-level atoms (the Josephson junction qubits) in an electromagnetic cavity (the nanomechanical resonator). However, here we can individually tune the level spacing of the "atoms" and control their "electromagnetic" interaction strength. We show that quantum states prepared in a Josephson junction can be passed to the nanomechanical resonator and stored there, and then can be passed back to the original junction or transferred to another with high fidelity. The resonator can also be used to produce maximally entangled Bell states between a pair of Josephson junctions.

  16. MACHINERY RESONANCE AND DRILLING

    SciTech Connect

    Leishear, R.; Fowley, M.

    2010-01-23

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

  17. Notes on Experiments.

    ERIC Educational Resources Information Center

    Physics Education, 1983

    1983-01-01

    An experiment on cooling by convection, holographic processes achieved using optical fibers and observation of magnetic domains are described. Also describes four demonstrations: mechanical resonance on air track, independence of horizontal/vertical motion, motion of sphere in fluid medium, and light scattering near the critical point. (JN)

  18. A Vibrating String Experiment

    ERIC Educational Resources Information Center

    Tsutsumanova, Gichka; Russev, Stoyan

    2013-01-01

    A simple experiment demonstrating the excitation of a standing wave in a metal string is presented here. Several tasks using the set-up are considered, which help the students to better understand the standing waves, the interaction between electric current and magnetic field and the resonance phenomena. This can serve also as a good lecture…

  19. Experimenting with Woodwind Instruments

    ERIC Educational Resources Information Center

    LoPresto, Michael C.

    2007-01-01

    Simple experiments involving musical instruments of the woodwind family can be used to demonstrate the basic physics of vibrating air columns in resonance tubes using nothing more than straightforward measurements and data collection hardware and software. More involved experimentation with the same equipment can provide insight into the effects…

  20. An NMR Kinetics Experiment.

    ERIC Educational Resources Information Center

    Kaufman, Don; And Others

    1982-01-01

    Outlines advantages of and provides background information, procedures, and typical student data for an experiment determining rate of hydration of p-methyoxyphenylacetylene (III), followed by nuclear magnetic resonance spectroscopy. Reaction rate can be adjusted to meet time framework of a particular laboratory by altering concentration of…