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Sample records for nuclear quadrupole resonances

  1. Nuclear quadrupole resonance studies in semi-metallic structures

    NASA Technical Reports Server (NTRS)

    Murty, A. N.

    1974-01-01

    Both experimental and theoretical studies are presented on spectrum analysis of nuclear quadrupole resonance of antimony and arsenic tellurides. Numerical solutions for secular equations of the quadrupole interaction energy are also discussed.

  2. 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.

  3. Nuclear Quadrupole Resonance Studies in MICA

    NASA Astrophysics Data System (ADS)

    Sengupta, S.; Rhadakrishna, S.; Marino, R. A.

    1986-02-01

    Aluminum-27 NQR transitions were detected in Muscovite Mica at room temperature using double resonance by level crossing (DRLC) techniques. Three lines were observed with frequencies of 572.5, 1052.0, and 1624.5 kHz. These lines are assigned to the octahedrally coordinated site, AlO4(OH)2. The corresponding quadrupole coupling constant, e2q Q/h, and asymmetry parameter, η, are 3554.8 kHz and 0.265, respectively. The remaining tetrahedrally coordinated sites, AlO4, gave no discernible signal, perhaps due to the greater 27Al- 1H distance.

  4. 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.

  5. Nuclear quadrupole resonance studies project. [spectrometer design and spectrum analysis

    NASA Technical Reports Server (NTRS)

    Murty, A. N.

    1978-01-01

    The participation of undergraduates in nuclear quadrupole resonance research at Grambling University was made possible by NASA grants. Expanded laboratory capabilities include (1) facilities for high and low temperature generation and measurement; (2) facilities for radio frequency generation and measurement with the modern spectrum analyzers, precision frequency counters and standard signal generators; (3) vacuum and glass blowing facilities; and (4) miscellaneous electronic and machine shop facilities. Experiments carried out over a five year period are described and their results analyzed. Theoretical studies on solid state crystalline electrostatic fields, field gradients, and antishielding factors are included.

  6. Sensitivity of nuclear-quadrupole double-resonance detection of half-integer spin nuclei

    NASA Astrophysics Data System (ADS)

    Seliger, J.; Žagar, V.

    2008-10-01

    The sensitivity of the Slusher and Hahn's nuclear quadrupole double resonance technique is calculated in general for an arbitrary nuclear spin S of the quadrupole nuclei and for an arbitrary asymmetry parameter η of the electric field gradient tensor. The nuclear spin S = 5/2 ( 17O, 25Mg, …) is treated in details. The influence of the cross-relaxation rate between the quadrupole nuclei and the abundant spin system on the sensitivity of double resonance is discussed. The results of the theoretical analysis are applied in the analysis of the 1H- 17O nuclear quadrupole double resonance spectra in p-toluenesulfonamide and 2-nitrobenzoic acid. The 17O nuclear quadrupole resonance frequencies from a sulfonamide group are determined for the first time. The proton-oxygen cross-relaxation rates and the proton local frequency in zero external magnetic field are experimentally determined from the nuclear quadrupole double resonance spectra.

  7. Revision of Spin Echoes in Pure Nuclear Quadrupole Resonance

    NASA Astrophysics Data System (ADS)

    Meriles, C. A.

    2001-04-01

    Goldman's spin-1/2 formalism has been used for describing the response of an I=3/2 spin system to a two-pulse sequence in a pure nuclear quadrupole resonance experiment. A detailed analysis of the polarization evolution and quadrupolar echo generation is carried out through the use of explicit expressions for secular homo- and heteronuclear dipolar interactions. In striking contrast with previous studies, it is predicted that Van Vleck's second moments governing a classical solid-echo or Hahn sequence differ from those obtained by equivalent means in magnetic resonance. In fact, it is shown that, although measured moments still complement each other, the combined use of standard sequences does not allow the separate determination of homo- and heteronuclear dipolar contributions to the linewidth, not even in an indirect manner. In this context, the importance and potential usefulness of a crossed coil probe are also briefly discussed.

  8. 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.

  9. Polarization enhanced Nuclear Quadrupole Resonance with an atomic magnetometer

    NASA Astrophysics Data System (ADS)

    Malone, Michael W.; Barrall, Geoffrey A.; Espy, Michelle A.; Monti, Mark C.; Alexson, Dimitri A.; Okamitsu, Jeffrey K.

    2016-05-01

    Nuclear Quadrupole Resonance (NQR) has been demonstrated for the detection of 14-N in explosive compounds. Application of a material specific radio-frequency (RF) pulse excites a response typically detected with a wire- wound antenna. NQR is non-contact and material specific, however fields produced by NQR are typically very weak, making demonstration of practical utility challenging. For certain materials, the NQR signal can be increased by transferring polarization from hydrogen nuclei to nitrogen nuclei using external magnetic fields. This polarization enhancement (PE) can enhance the NQR signal by an order of magnitude or more. Atomic magnetometers (AM) have been shown to improve detection sensitivity beyond a conventional antenna by a similar amount. AM sensors are immune to piezo-electric effects that hamper conventional NQR, and can be combined to form a gradiometer for effective RF noise cancellation. In principle, combining polarization enhancement with atomic magnetometer detection should yield improvement in signal-to-noise ratio that is the product of the two methods, 100-fold or more over conventional NQR. However both methods are even more exotic than traditional NQR, and have never been combined due to challenges in operating a large magnetic field and ultra-sensitive magnetic field sensor in proximity. Here we present NQR with and without PE with an atomic magnetometer, demonstrating signal enhancement greater than 20-fold for ammonium nitrate. We also demonstrate PE for PETN using a traditional coil for detection with an enhancement factor of 10. Experimental methods and future applications are discussed.

  10. Capacitor-based detection of nuclear magnetization: nuclear quadrupole resonance of surfaces.

    PubMed

    Gregorovič, Alan; Apih, Tomaž; Kvasić, Ivan; Lužnik, Janko; Pirnat, Janez; Trontelj, Zvonko; Strle, Drago; Muševič, Igor

    2011-03-01

    We demonstrate excitation and detection of nuclear magnetization in a nuclear quadrupole resonance (NQR) experiment with a parallel plate capacitor, where the sample is located between the two capacitor plates and not in a coil as usually. While the sensitivity of this capacitor-based detection is found lower compared to an optimal coil-based detection of the same amount of sample, it becomes comparable in the case of very thin samples and even advantageous in the proximity of conducting bodies. This capacitor-based setup may find its application in acquisition of NQR signals from the surface layers on conducting bodies or in a portable tightly integrated nuclear magnetic resonance sensor.

  11. 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.

  12. The fluorinated (10, 0) boron nitride nanotube: a computational nuclear magnetic resonance and nuclear quadrupole resonance study.

    PubMed

    Seif, Ahmad; Boshra, Asadollah; Bodaghi, Ali

    2010-01-01

    Quantum chemical calculations at the level of density functional theory (DFT) were carried out to investigate the influence of fluorination boron and nitrogen nuclear magnetic resonance (NMR) and also nuclear quadrupole resonance (NQR) parameters in the (10, 0) single-wall boron nitride nanotube (SWBNNT). To achieve this aim three models of (10, 0) boron nitride nanotubes (BNNTs), raw and two F-attached (exohedral and endohedral) derivatives were studied. The results of calculations showed that while the boron atom chemically bonded to F atom has the largest chemical shielding isotropy (CSI); it has the smallest quadrupole coupling constant (CQ) value among the other boron nuclei.

  13. A novel power amplification scheme for nuclear magnetic resonance/nuclear quadrupole resonance systems.

    PubMed

    Zhang, Xinwang; Schemm, Nathan; Balkır, Sina

    2011-03-01

    Nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR)-based chemical analysis systems have been widely utilized in various areas such as medicine, security, and academic research. In these applications, the power amplifier stage plays a key role in generating the required oscillating magnetic fields within a radio frequency coil that serves as the probe. However, the bulky size and relatively low efficiency of the traditional power amplification schemes employed present a bottleneck for the realization of compact sized and portable NMR and NQR systems. To address this problem, this work presents a class D voltage-switching power amplification scheme with novel fast-start and fast-stop functions that are suitable for generating ideal NMR and NQR excitation signals. Compared to the traditional analog power amplifiers (PAs), the proposed switched-mode PA can achieve significant improvement on the power efficiency as well as the physical volume. A PA circuit for portable NQR-based explosive detection systems has been designed and built using the proposed scheme with 1 kW possible maximum output power and 10 MHz maximum operating frequency. Test results show that the presented PA achieves more than 60% measured efficiency within a highly compact volume while sustaining fast start and stop of excitation signals in the order of microseconds.

  14. DC superconducting quantum interference device usable in nuclear quadrupole resonance and zero field nuclear magnetic spectrometers

    DOEpatents

    Fan, N.Q.; Clarke, J.

    1993-10-19

    A spectrometer for measuring the nuclear quadrupole resonance spectra or the zero-field nuclear magnetic resonance spectra generated by a sample is disclosed. The spectrometer uses an amplifier having a dc SQUID operating in a flux-locked loop for generating an amplified output as a function of the intensity of the signal generated by the sample. The flux-locked loop circuit includes an integrator. The amplifier also includes means for preventing the integrator from being driven into saturation. As a result, the time for the flux-locked loop to recover from the excitation pulses generated by the spectrometer is reduced. 7 figures.

  15. DC superconducting quantum interference device usable in nuclear quadrupole resonance and zero field nuclear magnetic spectrometers

    DOEpatents

    Fan, Non Q.; Clarke, John

    1993-01-01

    A spectrometer for measuring the nuclear quadrupole resonance spectra or the zero-field nuclear magnetic resonance spectra generated by a sample is disclosed. The spectrometer uses an amplifier having a dc SQUID operating in a flux-locked loop for generating an amplified output as a function of the intensity of the signal generated by the sample. The flux-locked loop circuit includes an integrator. The amplifier also includes means for preventing the integrator from being driven into saturation. As a result, the time for the flux-locked loop to recover from the excitation pulses generated by the spectrometer is reduced.

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

    PubMed

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

    1992-11-01

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

  17. Utilization of pure nuclear quadrupole resonance spectroscopy for the study of pharmaceutical crystal forms.

    PubMed

    Pérez, S C; Cerioni, L; Wolfenson, A E; Faudone, S; Cuffini, S L

    2005-07-14

    Solid-state physical characterization of a pharmaceutical substance is necessary for successful development and approval of the final product. Different physical analytical techniques are available to do so: X-ray diffraction (XRD), IR, Raman, DSC, TG and NMR. Moreover, all of them detect the presence of excipients perturbing the analysis of the pure substance in low doses. In order to study polymorphism and pseudo polymorphism of drug, this paper introduces possible applications of pure nuclear quadrupole resonance, as a non-destructive technique in qualitative and quantitative approaches. Chlorpropamide and diclofenac sodium were used as examples. Unlike the mentioned techniques, the nuclear quadrupole resonance (NQR) signal of pharmaceutical compounds is not perturbed by the presence of solid excipient or other substances unless they possess resonance frequencies in the same frequency range of the compound studied.

  18. 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.

  19. 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.

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

    PubMed

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

    2011-12-14

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

  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. Enhancing nuclear quadrupole resonance (NQR) signature detection leveraging interference suppression algorithms

    NASA Astrophysics Data System (ADS)

    DeBardelaben, James A.; Miller, Jeremy K.; Myrick, Wilbur L.; Miller, Joel B.; Gilbreath, G. Charmaine; Bajramaj, Blerta

    2012-06-01

    Nuclear quadrupole resonance (NQR) is a radio frequency (RF) magnetic spectroscopic technique that has been shown to detect and identify a wide range of explosive materials containing quadrupolar nuclei. The NQR response signal provides a unique signature of the material of interest. The signal is, however, very weak and can be masked by non-stationary RF interference (RFI) and thermal noise, limiting detection distance. In this paper, we investigate the bounds on the NQR detection range for ammonium nitrate. We leverage a low-cost RFI data acquisition system composed of inexpensive B-field sensing and commercial-off-the-shelf (COTS) software-defined radios (SDR). Using collected data as RFI reference signals, we apply adaptive filtering algorithms to mitigate RFI and enable NQR detection techniques to approach theoretical range bounds in tactical environments.

  3. Methods of spectral estimation in local nuclear quadrupole resonance with a dispersion

    NASA Astrophysics Data System (ADS)

    Grechishkin, V. S.; Grechishkina, R. V.; Persichkin, A. A.; Shpilevoi, A. A.

    2002-10-01

    The spectral estimation in local nuclear quadrupole resonance at a high noise level is performed for the first time using the modern techniques of linear prediction (LPSVD) and matrix pencil (ITMPM). The fast Fourier transform with signal accumulation does not ensure the required sensitivity in the case of weak signals when the object and the receiver of the spectrometer are spaced widely apart or when there is an effect of adverse factors (screening, interference, random disturbance, etc.), which is typical of remote monitoring in actual practice. It is demonstrated that the use of the proposed techniques considerably increases the efficiency of spectral estimation in this field of solid-state spectroscopy and, in particular, avoids the phase errors arising in usual experiments at a signal-to-noise ratio of less than 0.5.

  4. Extended nuclear quadrupole resonance study of the heavy-fermion superconductor PuCoGa5

    NASA Astrophysics Data System (ADS)

    Koutroulakis, G.; Yasuoka, H.; Tobash, P. H.; Mitchell, J. N.; Bauer, E. D.; Thompson, J. D.

    2016-10-01

    PuCoGa5 has emerged as a prototypical heavy-fermion superconductor, with its transition temperature (Tc≃18.5 K) being the highest amongst such materials. Nonetheless, a clear description as to what drives the superconducting pairing is still lacking, rendered complicated by the notoriously intricate nature of plutonium's 5 f valence electrons. Here, we present a detailed Ga,7169 nuclear quadrupole resonance (NQR) study of PuCoGa5, concentrating on the system's normal state properties near to Tc and aiming to detect distinct signatures of possible pairing mechanisms. In particular, the quadrupole frequency and spin-lattice relaxation rate were measured for the two crystallographically inequivalent Ga sites and for both Ga isotopes, in the temperature range 1.6-300 K. No evidence of significant charge fluctuations is found from the NQR observables. On the contrary, the low-energy dynamics is dominated by anisotropic spin fluctuations with strong, nearly critical, in-plane character, which are effectively identical to the case of the sister compound PuCoIn5. These findings are discussed within the context of different theoretical proposals for the unconventional pairing mechanism in heavy-fermion superconductors.

  5. Determination of the magnitude and sign of the 185,187Re nuclear electric quadrupole coupling constants using nuclear acoustic resonance

    NASA Astrophysics Data System (ADS)

    Sundfors, R. K.

    1990-08-01

    Acoustic nuclear electric quadrupole resonance spectra and the magnitude and sign of the coupling constants for 185Re and 187Re in rhenium-metal single crystals have been measured using nuclear acoustic resonance (NAR) in a small magnetic field. These measurements were carried out using a NAR reflection bridge spectrometer in the 37-41 MHz frequency range and at 4.2 and 77.8 K. In this hexagonal crystal, the dynamic coupling between acoustic waves and the Re nuclear spin systems is shown to be via the dynamic quadrupole interaction, which is responsible for the observation of both Δm=+/-1 and +/-2 transitions between the +/-3/2 energy levels and the mixed +/-1/2 energy levels. Magnetic-resonance second moments for angular-independent indirect exchange broadening and angular-dependent static electric quadrupole broadening (from a spread in the electric quadrupole coupling constant value) are determined from the measured linewidths.

  6. Noise-resilient multi-frequency surface sensor for nuclear quadrupole resonance.

    PubMed

    Peshkovsky, A S; Cattena, C J; Cerioni, L M; Osán, T M; Forguez, J G; Peresson, W J; Pusiol, D J

    2008-10-01

    A planar nuclear quadrupole resonance (NQR) sensor has been developed. The sensor is resilient to environmental noise and is capable of simultaneous independent multi-frequency operation. The device was constructed as an open multimodal birdcage structure, in which the higher modes, generally not used in magnetic resonance, are utilized for NQR detection. These modes have smooth distributions of the amplitudes of the corresponding radiofrequency magnetic fields everywhere along the sensor's surface. The phases of the fields, on the other hand, are cyclically shifted across the sensor's surface. Noise signals coming from distant sources, therefore, induce equal-magnitude cyclically phase-shifted currents in different parts of the sensor. When such cyclically phase-shifted currents arrive at the mode connection point, they destructively interfere with each other and are cancelled out. NQR signals of polycrystalline or disordered substances, however, are efficiently detected by these modes because they are insensitive to the phases of the excitation/detection. No blind spots exist along the sensor's surface. The sensor can be used for simultaneous detection of one or more substances in locations with environmental noise.

  7. 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.

  8. 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.

  9. Coulomb disorder effects on angle-resolved photoemission and nuclear quadrupole resonance spectra in cuprates

    NASA Astrophysics Data System (ADS)

    Chen, Wei; Khaliullin, Giniyat; Sushkov, Oleg P.

    2009-09-01

    The role of Coulomb disorder, either of extrinsic origin or introduced by dopant ions in undoped and lightly doped cuprates, is studied. We demonstrate that charged surface defects in an insulator lead to a Gaussian broadening of the angle-resolved photoemisson spectroscopy (ARPES) lines. The effect is due to the long-range nature of the Coulomb interaction. A tiny surface concentration of defects about a fraction of one percent is sufficient to explain the line broadening observed in Sr2CuO2Cl2 , La2CuO4 , and Ca2CuO2Cl2 . Due to the Coulomb screening, the ARPES spectra evolve dramatically with doping, changing their shape from a broad Gaussian form to narrow Lorentzian ones. To understand the screening mechanism and the line-shape evolution in detail, we perform Hartree-Fock simulations with random positions of surface defects and dopant ions. To check validity of the model we calculate the nuclear quadrupole resonance (NQR) line shapes as a function of doping and reproduce the experimentally observed NQR spectra. Our study also indicates opening of a substantial Coulomb gap at the chemical potential. For a surface CuO2 layer the value of the gap is on the order of 10 meV while in the bulk it is reduced to the value about a few meV.

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

    NASA Astrophysics Data System (ADS)

    Cho, Herman

    2016-09-01

    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. Applications of NQR methods to studies of electronic structure in heavy element systems are proposed.

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

    DOE PAGES

    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.

  12. WURST-QCPMG sequence and "spin-lock" in 14N nuclear quadrupole resonance

    NASA Astrophysics Data System (ADS)

    Gregorovič, Alan; Apih, Tomaž

    2013-08-01

    14N nuclear quadrupole resonance (NQR) is a promising method for the analysis of pharmaceuticals or for the detection of nitrogen based illicit compounds, but so far, the technique is still not widely used, mostly due to the very low sensitivity. This problem is already acute in the preliminary NQR stage, when a compound is being examined for the first time and the NQR frequencies are being searched for, by scanning a wide frequency range step-by-step. In the present work, we experimentally show how to increase the efficiency of this initial stage by using a combination of a wideband excitation achieved with frequency swept pulses (WURST) and a "spin-lock" state obtained with a quadrupolar-CPMG (QCPMG) sequence. In the first part we show that WURST pulses provide a much larger excitation bandwidth compared to common rectangular pulses. This increased bandwidth allows to increase the frequency step and reduces the total number of steps in a scanning stage. In the second part we show that the "spin-lock" decay time T2eff obtained with the WURST-QCPMG combination is practically identical with the T2eff obtained with the most common "spin-lock" sequence, the SLSE, despite a very different nature and length of excitation pulses. This allows for a substantial S/N increase through echo averaging in every individual step and really allows to exploit all the advantages of the wider excitation in the NQR frequency scanning stage. Our experimental results were obtained on a sample of trinitrotoluene, but identical behavior is expected for all compounds where a "spin-lock" state can be created.

  13. Nuclear Quadrupole Moments and Nuclear Shell Structure

    DOE R&D Accomplishments Database

    Townes, C. H.; Foley, H. M.; Low, W.

    1950-06-23

    Describes a simple model, based on nuclear shell considerations, which leads to the proper behavior of known nuclear quadrupole moments, although predictions of the magnitudes of some quadrupole moments are seriously in error.

  14. Quadrupole Induced Resonant Particle Transport

    NASA Astrophysics Data System (ADS)

    Gilson, Erik; Fajans, Joel

    1998-11-01

    We have performed experiments that explore the effects of a magnetic quadrupole field on a pure electron plasma confined in a Penning-Malmberg trap. A model that we have developed describes the shape of the plasma and shows that a certain class of resonant particles follows trajectories that take them out of the plasma. Even though the quadrupole field destroys the cylindrical symmetry of the system, our theory predicts that if the electrons are off resonance, then the lifetime of the plasma will not be greatly affected by the quadrupole field. Our preliminary experimental results show that the shape of the plasma and the plasma lifetime agree with our model. We are investigating the scaling of this behavior with various experimental parameters such as the plasma length, density, and strength of the quadrupole field. In addition to being an example of resonant particle transport, this effect may find practical applications in experiments that plan to use magnetic quadrupole neutral atom traps to confine anti-hydrogen created in double-well positron/anti-proton Penning-Malmberg traps. (ATHENA Collaboration.)

  15. Quadrupole Induced Resonant Particle Transport

    NASA Astrophysics Data System (ADS)

    Gilson, Erik; Fajans, Joel

    1999-11-01

    We have performed experiments that explore the effects of a magnetic quadrupole field on a pure electron plasma confined in a Malmberg-Penning trap. A model that we have developed describes the shape of the plasma and shows that a certain class of resonant particles follows trajectories that take them out of the plasma. Even though the quadrupole field destroys the cylindrical symmetry of the system, our theory predicts that if the electrons are off resonance, then the lifetime of the plasma will not be greatly affected by the quadrupole field. Our preliminary experimental results show that the shape of the plasma and the plasma lifetime agree with our model. We are investigating the scaling of this behavior with various experimental parameters such as the plasma length, density, and strength of the quadrupole field. In addition to being an example of resonant particle transport, this effect may find practical applications in experiments that plan to use magnetic quadrupole neutral atom traps to confine anti-hydrogen created in double-well positron/anti-proton Malmberg-Penning traps. (ATHENA Collaboration.)

  16. Characterization of solid phases and study of transformation kinetics in m-chlorofluorobenzene by 35Cl nuclear quadrupole resonance.

    PubMed

    Pérez, Silvina; Wolfenson, Alberto

    2012-02-01

    Polymorphism is of widespread occurrence in the world of molecular crystals. In this work we present experimental results showing the existence of four solid phases in m-chlorofluorobenzene. A glass structure is achieved by quenching the liquid phase at 77 K. This glassy state crystallizes in a disordered phase at T~143 K, which in turn transforms to the high-temperature stable phase (phase I) at T~153 K. Depending on the thermal history of the sample, a different ordered phase (phase III) can be obtained. The disorder is attributed to a molecular orientational disorder. There is no evidence of molecular reorientation in any phase. A study of the disorder-order phase transformation kinetics, using nuclear quadrupole resonance, is presented. The results are analyzed following Cahn's theory. Nucleation seems to take place at grain boundaries. Growth rates for different temperatures have been determined.

  17. Nuclear quadrupole resonance study of local bonding in glassy As{sub x}Se{sub 1-x}

    SciTech Connect

    Ahn, Eungho; Williams, G. A.; Taylor, P. C.

    2006-11-01

    Nuclear quadrupole resonance (NQR) experiments were performed on glassy As{sub x}Se{sub 1-x} to study the local structural order. The bonding in As{sub x}Se{sub 1-x} is governed by preferential bonding (chemical ordering) between arsenic and selenium at arsenic concentrations x{<=}0.40; however, the bonding for higher arsenic concentrations is governed mostly by statistical considerations. At concentrations x{>=}0.45 the glasses are inhomogeneous with the presence of local regions of different composition. Measurements of the NQR spin echo intensity identify regions formed by arsenic atoms bonded to zero, one, two, or three selenium atoms. The NQR spectral line shapes and the longitudinal relaxation times suggest that these regions have a more ordered structure as compared to the homogeneous samples with low arsenic content. The existence of a small concentration of crystalline inclusions in amorphous As{sub 0.60}Se{sub 0.40} is also suggested.

  18. 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.

  19. 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.

  20. 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.

  1. A study of the semiconductor compound СuAlO2 by the method of nuclear quadrupole resonance of Cu

    NASA Astrophysics Data System (ADS)

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

    2012-07-01

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

  2. 93Nb Nuclear Quadrupole Resonance in Orthorhombic Phase of Niobium Pentabromide

    NASA Astrophysics Data System (ADS)

    Okubo, Noriaki; Abe, Yoshihito

    1982-05-01

    The 93Nb NQR has been investigated in one phase of NbBr5 which was identified to be orthorhombic by the X-ray analysis. The resonance frequencies have been measured between 4.2 K and 423 K, its melting point. The coupling constant showed a positive temperature dependence up to melting point. The temperature dependence of the coupling constant is compared between NbBr5 and NbCl5 from the view point of π-bond character.

  3. Radio frequency quadrupole resonator for linear accelerator

    DOEpatents

    Moretti, Alfred

    1985-01-01

    An RFQ resonator for a linear accelerator having a reduced level of interfering modes and producing a quadrupole mode for focusing, bunching and accelerating beams of heavy charged particles, with the construction being characterized by four elongated resonating rods within a cylinder with the rods being alternately shorted and open electrically to the shell at common ends of the rods to provide an LC parallel resonant circuit when activated by a magnetic field transverse to the longitudinal axis.

  4. 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.

  5. Detection of an unconventional superconducting phase in the vicinity of the strong first-order magnetic transition in CrAs using (75)As-nuclear quadrupole resonance.

    PubMed

    Kotegawa, Hisashi; Nakahara, Shingo; Akamatsu, Rui; Tou, Hideki; Sugawara, Hitoshi; Harima, Hisatomo

    2015-03-20

    Pressure-induced superconductivity was recently discovered in the binary helimagnet CrAs. We report the results of measurements of nuclear quadrupole resonance for CrAs under pressure. In the vicinity of the critical pressure P(c) between the helimagnetic (HM) and paramagnetic (PM) phases, a phase separation is observed. The large internal field remaining in the phase-separated HM state indicates that the HM phase disappears through a strong first-order transition. This indicates the absence of a quantum critical point in CrAs; however, the nuclear spin-lattice relaxation rate 1/T(1) reveals that substantial magnetic fluctuations are present in the PM state. The absence of a coherence effect in 1/T(1) in the superconducting state provides evidence that CrAs is the first Cr-based unconventional superconductor. PMID:25839303

  6. Detection of an unconventional superconducting phase in the vicinity of the strong first-order magnetic transition in CrAs using (75)As-nuclear quadrupole resonance.

    PubMed

    Kotegawa, Hisashi; Nakahara, Shingo; Akamatsu, Rui; Tou, Hideki; Sugawara, Hitoshi; Harima, Hisatomo

    2015-03-20

    Pressure-induced superconductivity was recently discovered in the binary helimagnet CrAs. We report the results of measurements of nuclear quadrupole resonance for CrAs under pressure. In the vicinity of the critical pressure P(c) between the helimagnetic (HM) and paramagnetic (PM) phases, a phase separation is observed. The large internal field remaining in the phase-separated HM state indicates that the HM phase disappears through a strong first-order transition. This indicates the absence of a quantum critical point in CrAs; however, the nuclear spin-lattice relaxation rate 1/T(1) reveals that substantial magnetic fluctuations are present in the PM state. The absence of a coherence effect in 1/T(1) in the superconducting state provides evidence that CrAs is the first Cr-based unconventional superconductor.

  7. Explosives detection with quadrupole resonance analysis

    NASA Astrophysics Data System (ADS)

    Rayner, Timothy J.; Thorson, Benjamin D.; Beevor, Simon; West, Rebecca; Krauss, Ronald A.

    1997-02-01

    The increase in international terrorist activity over the past decade has necessitated the exploration of new technologies for the detection of plastic explosives. Quadrupole resonance analysis (QRA) has proven effective as a technique for detecting the presence of plastic, sheet, and military explosive compounds in small quantities, and can also be used to identify narcotics such as heroin and cocaine base. QRA is similar to the widely used magnetic resonance (MR) and magnetic resonance imaging (MRI) techniques, but has the considerable advantage that the item being inspected does not need to be immersed in a steady, homogeneous magnetic field. The target compounds are conclusively identified by their unique quadrupole resonance frequencies. Quantum magnetics has develop and introduced a product line of explosives and narcotics detection devices based upon QRA technology. The work presented here concerns a multi-compound QRA detection system designed to screen checked baggage, cargo, and sacks of mail at airports and other high-security facilities. The design philosophy and performance are discussed and supported by test results from field trials conducted in the United States and the United Kingdom. This detection system represents the current state of QRA technology for field use in both commercial and government sectors.

  8. Identification of chloride-binding sites in hemoglobin by nuclear-magnetic-resonance quadrupole-relaxation studies of hemoglobin digests.

    PubMed

    Chiancone, E; Norne, J E; Forsén, S; Bonaventura, J; Brunori, M; Antonini, E; Wyman, J

    1975-07-01

    35Cl minus-nuclear magnetic resonance (NMR) studies indicate that various digests of human hemoglobin with carboxypeptidase A and B, or a combination of the two, may be used for the identification of chloride binding sites. All the digestion products contain, like hemoglobin itself, at least two classes of binding sites, one of high, the others of low affinity. The pH dependence of the excess linewidth of the 35Cl minus NMR signal indicates that in the simple digests with either carboxypeptidase A or B, chloride is bound with high affinity at or near His-beta146-Asp-beta94 and at or near Val-alpha1-Arg-alpha141. The high-affinity sites show, in the case of the simple digests, a strong oxygen linkage which is lost in the forms digested with both carboxypeptidase A and B; this linkage may thus be correlated to the presence of conformational changes. Organic phosphates, like inositol hexaphosphate, show competition for some of the high-affinity chloride binding sites in hemoglobin and in the simple digests. This competition is likewise lost in the doubly digested hemoglobins. PMID:236

  9. Nuclear Quadrupole Double Resonance Investigation of the Anomalous Temperature Coefficients of the Strong Hydrogen Bonds in Sodium and Potassium Deuterium Diacetate.

    NASA Astrophysics Data System (ADS)

    Shaw, Eric Max

    This thesis was directed at learning more about the unusual electronic environment near hydrogen within strong hydrogen bonds. "Strong" hydrogen bonds are unique in that the hydrogen atom is symmetrically located, or nearly so, between two electronegative atoms; the bond energies are relatively large. In a "normal" hydrogen bond the hydrogen atom is bonded to, and thus physically closer to, a parent atom, and only weakly attracted to another electronegative atom; bond energies are typically small. To examine these bonds, deuterium was substituted for hydrogen and the electric quadrupole coupling constant (QCC) of deuterium was measured using field cycling nuclear magnetic resonance. The electric quadrupole moment of deuterium is sensitive to changes in the surrounding electric field gradient, and is thus a good probe of the immediate electronic structure. The results show that the temperature dependence of the QCC is opposite to, and much larger than, what one would normally expect to observe for deuterium. The QCC is found to decrease strongly with decreasing temperature. This project was the first to study in detail the temperature dependence of deuterium QCCs in strong hydrogen bonds. The magnitude of the deuterium QCCs for the diacetates was found to be strongly depressed relative to typical values for deuterium. These results parallel large shifts in the infrared vibrational frequencies observed in many molecules which contain strong hydrogen bonds. The asymmetry parameter, which is a measure of the departure from axial symmetry of the electric field gradient (EFG) at deuterium, was found to be unusually large for what are known to be linear, or nearly linear, three-center bonds. Based on ab initio Hartree-Fock calculations aimed at determining the EFG at H in the archetypal bifluoride ion, F-H-F^-, the electronic charge density is drastically depleted at H. It is believed that the large reduction in the charge density allows the deuterium EFG to be highly

  10. An analytical method for estimating the {sup 14}N nuclear quadrupole resonance parameters of organic compounds with complex free induction decays for radiation effects studies

    SciTech Connect

    Iselin, L.H.

    1992-12-31

    The use of {sup 14}N nuclear quadrupole resonance (NQR) as a radiation dosimetry tool has only recently been explored. An analytical method for analyzing {sup 14}N NQR complex free induction decays is presented with the background necessary to conduct pulsed NQR experiments. The {sup 14}N NQR energy levels and possible transitions are derived in step-by-step detail. The components of a pulsed NQR spectrometer are discussed along with the experimental techniques for conducting radiation effects experiments using the spectrometer. Three data analysis techniques -- the power spectral density Fourier transform, state space singular value decomposition (HSVD), and nonlinear curve fitting (using the downhill simplex method of global optimization and the Levenberg-Marquart method) -- are explained. These three techniques are integrated into an analytical method which uses these numerical techniques in this order to determine the physical NQR parameters. Sample data sets of urea and guanidine sulfate data are used to demonstrate how these methods can be employed to analyze both simple and complex free induction decays. By determining baseline values for biologically significant organics, radiation effects on the NQR parameters can be studied to provide a link between current radiation dosimetry techniques and the biological effects of radiation.

  11. The nuclear electric quadrupole moment of copper.

    PubMed

    Santiago, Régis Tadeu; Teodoro, Tiago Quevedo; Haiduke, Roberto Luiz Andrade

    2014-06-21

    The nuclear electric quadrupole moment (NQM) of the (63)Cu nucleus was determined from an indirect approach by combining accurate experimental nuclear quadrupole coupling constants (NQCCs) with relativistic Dirac-Coulomb coupled cluster calculations of the electric field gradient (EFG). The data obtained at the highest level of calculation, DC-CCSD-T, from 14 linear molecules containing the copper atom give rise to an indicated NQM of -198(10) mbarn. Such result slightly deviates from the previously accepted standard value given by the muonic method, -220(15) mbarn, although the error bars are superimposed.

  12. Nuclear Magnetic resonance quadrupole relaxation studies of chloride binding to the isolated hemoglobins from trout (Salmo irideus).

    PubMed

    Chiancone, E; Norne, J E; Forsén, S; Brunori, M; Antonini, E

    1975-02-01

    NMR studies of chloride binding to the main components of trout blood, Hb Trout I and Hb Trout IV, indicate that although the affinity of chloride is high for both hemoglobins, the characteristics of the binding process are markedly differnet. In Hb Trout IV chemical exchange at the chloride binding site(s) is fast and quadrupole effects determine the linewidth; chloride binding has a definite pH dependence, but there is no significant oxygen linkage. In contrast Hb Trout I represents a unique case of slow chemical exchange, which may depend on unusual stereoche mical characteristics of the chloride binding site; chloride binding is pH independent, but shows a significant oxygen linkage, which may be attributed to changes of the lifetime of chloride at the binding site. The chloride binding properties displayed by Hb Trout I and IV have been compared with those of normal and modified human hemoglobins and discussed in terms of the structural differences in the C- and N-terminal regions of the alpha- and beta-chains. PMID:236050

  13. Quadrupole resonance scanner for narcotics detection

    NASA Astrophysics Data System (ADS)

    Shaw, Julian D.; Moeller, C. R.; Magnuson, Erik E.; Sheldon, Alan G.

    1994-10-01

    Interest in non-invasive, non-hazardous, bulk detection technologies for narcotics interdiction has risen over the last few years. As part of our continuing research and development programs in detection of narcotics and explosives using sensitive magnetic measuring devices, we present the first commercially available prototype Quadrupole Resonance (QR) scanner for narcotics detection. The portable narcotics detection system was designed in modular form such that a single QR base system could be easily used with a variety of custom detection heads. The QR system presented in this paper is suitable for scanning items up to 61 X 35 X 13 cm in size, and was designed to scan mail packages and briefcase-sized items for the presence of narcotics. System tests have shown that detection sensitivity is comparable that obtained in laboratory systems.

  14. Development of a quadrupole resonance confirmation system

    NASA Astrophysics Data System (ADS)

    Barrall, Geoffrey A.; Derby, Kevin A.; Drew, Adam J.; Ermolaev, Konstantine V.; Huo, Shouqin; Lathrop, Daniel K.; Petrov, Todor R.; Steiger, Matthew J.; Stewart, Stanley H.; Turner, Peter J.

    2004-09-01

    Quantum Magnetics has developed a Quadrupole Resonance (QR) system for the detection of anti-tank and anti-vehicle landmines. The QR confirmation sensor (QRCS) is a part of the Army GSTAMIDS Block 1 program and is designed to confirm the presence of landmines initially flagged by a primary sensor system. The ultimate goal is to significantly reduce the number of sites that require neutralization or other time consuming investigation into the presence of a landmine. Government tests in 2002 and 2003 demonstrated the performance of the system in a wide variety of conditions including high radio frequency interference (RFI) and piezo electric ringing (PER) environments. Field test results are presented along with an overall description of the system design and methods used to solve prior issues with RFI and PER.

  15. Quadrupole resonance spectroscopic study of narcotic materials

    NASA Astrophysics Data System (ADS)

    Rayner, Timothy J.; West, Rebecca; Garroway, Allen N.; Lyndquist, R.; Yesinowski, James P.

    1997-02-01

    Bulk narcotic detection systems based upon Quadrupole Resonance Analysis (QRA) technology have a major advantage over imaging technologies, in that QRA is chemical-specific and consequently has a lower rate of false alarms. QRA is a magnetic resonance technology which occurs as a result of the inherent molecular properties of the atomic nuclei in crystalline and amorphous solids. The QRA response is characterized by 1) the precessional frequency of the nucleus, and 2) the nature of the electric field gradient experienced by the nucleus,due to its molecular environment. Another important detection parameter is linewidth, resonant quality. All of these parameters depend on sample purity and manufacturing process. Quantum Magnetics recently carried out a study on the QRA signatures of various narcotic materials with the support of the US Army, US Customs, and the Office of National Drug Control Policy. The aim of the study was to fully characterize the variation in QRA spectroscopic parameters of different samples of cocaine base and cocaine hydrochloride. The results from this study ar discussed here.

  16. Nuclear quadrupole moment of the {sup 99}Tc ground state

    SciTech Connect

    Errico, Leonardo; Darriba, German; Renteria, Mario; Tang Zhengning; Emmerich, Heike; Cottenier, Stefaan

    2008-05-15

    By combining first-principles calculations and existing nuclear magnetic resonance (NMR) experiments, we determine the quadrupole moment of the 9/2{sup +} ground state of {sup 99}Tc to be (-)0.14(3)b. This confirms the value of -0.129(20)b, which is currently believed to be the most reliable experimental determination, and disagrees with two earlier experimental values. We supply ab initio calculated electric-field gradients for Tc in YTc{sub 2} and ZrTc{sub 2}. If this calculated information would be combined with yet to be performed Tc-NMR experiments in these compounds, the error bar on the {sup 99}Tc ground state quadrupole moment could be further reduced.

  17. Table of nuclear electric quadrupole moments

    NASA Astrophysics Data System (ADS)

    Stone, N. J.

    2016-09-01

    This Table is a compilation of experimental measurements of static electric quadrupole moments of ground states and excited states of atomic nuclei throughout the periodic table. To aid identification of the states, their excitation energy, half-life, spin and parity are given, along with a brief indication of the method and any reference standard used in the particular measurement. Experimental data from all quadrupole moment measurements actually provide a value of the product of the moment and the electric field gradient [EFG] acting at the nucleus. Knowledge of the EFG is thus necessary to extract the quadrupole moment. A single recommended moment value is given for each state, based, for each element, wherever possible, upon a standard reference moment for a nuclear state of that element studied in a situation in which the electric field gradient has been well calculated. For several elements one or more subsidiary EFG/moment reference is required and their use is specified. The literature search covers the period to mid-2015.

  18. Detection of an Unconventional Superconducting Phase in the Vicinity of the Strong First-Order Magnetic Transition in CrAs Using As 75 -Nuclear Quadrupole Resonance

    NASA Astrophysics Data System (ADS)

    Kotegawa, Hisashi; Nakahara, Shingo; Akamatsu, Rui; Tou, Hideki; Sugawara, Hitoshi; Harima, Hisatomo

    2015-03-01

    Pressure-induced superconductivity was recently discovered in the binary helimagnet CrAs. We report the results of measurements of nuclear quadrupole resonance for CrAs under pressure. In the vicinity of the critical pressure Pc between the helimagnetic (HM) and paramagnetic (PM) phases, a phase separation is observed. The large internal field remaining in the phase-separated HM state indicates that the HM phase disappears through a strong first-order transition. This indicates the absence of a quantum critical point in CrAs; however, the nuclear spin-lattice relaxation rate 1 /T1 reveals that substantial magnetic fluctuations are present in the PM state. The absence of a coherence effect in 1 /T1 in the superconducting state provides evidence that CrAs is the first Cr-based unconventional superconductor.

  19. Radio-frequency quadrupole resonator for linear accelerator

    DOEpatents

    Moretti, A.

    1982-10-19

    An RFQ resonator for a linear accelerator having a reduced level of interfering modes and producing a quadrupole mode for focusing, bunching and accelerating beams of heavy charged particles, with the construction being characterized by four elongated resonating rods within a cylinder with the rods being alternately shorted and open electrically to the shell at common ends of the rods to provide an LC parallel resonant circuit when activated by a magnetic field transverse to the longitudinal axis.

  20. Comparison of nuclear electric resonance and nuclear magnetic resonance in integer and fractional quantum Hall states

    SciTech Connect

    Tomimatsu, Toru Shirai, Shota; Hashimoto, Katsushi Sato, Ken; Hirayama, Yoshiro

    2015-08-15

    Electric-field-induced nuclear resonance (NER: nuclear electric resonance) involving quantum Hall states (QHSs) was studied at various filling factors by exploiting changes in nuclear spins polarized at quantum Hall breakdown. Distinct from the magnetic dipole interaction in nuclear magnetic resonance, the interaction of the electric-field gradient with the electric quadrupole moment plays the dominant role in the NER mechanism. The magnitude of the NER signal strongly depends on whether electronic states are localized or extended. This indicates that NER is sensitive to the screening capability of the electric field associated with QHSs.

  1. Topology of the interactions pattern in pharmaceutically relevant polymorphs of methylxanthines (caffeine, theobromine, and theophiline): combined experimental (¹H-¹⁴N nuclear quadrupole double resonance) and computational (DFT and Hirshfeld-based) study.

    PubMed

    Latosińska, Jolanta Natalia; Latosińska, Magdalena; Olejniczak, Grzegorz A; Seliger, Janez; Žagar, Veselko

    2014-09-22

    Three anhydrous methylxanthines: caffeine (1,3,7-trimethylxanthine; 1,3,7-trimethyl-1H-purine-2,6-(3H,7H)-dione) and its two metabolites theophylline (1,3-dimethylxanthine; 1,3-dimethyl-7H-purine-2,6-dione) and theobromine (3,7-dimethyl-xanthine; 3,7-dimethyl-7H-purine-2,6-dione), which reveal multifaceted therapeutic potential, have been studied experimentally in solid state by (1)H-(14)N NMR-NQR (nuclear magnetic resonance-nuclear quadrupole resonance) double resonance (NQDR). For each compound the complete NQR spectrum consisting of 12 lines was recorded. The multiplicity of NQR lines indicates the presence of a stable β form of anhydrous caffeine at 233 K and stable form II of anhydrous theobromine at 213 K. The assignment of signals detected in NQR experiment to particular nitrogen atoms was made on the basis of quantum chemistry calculations performed for monomer, cluster, and solid at the DFT/GGA/BLYP/DPD level. The shifts due to crystal packing interactions were evaluated, and the multiplets detected by NQR were assigned to N(9) in theobromine and N(1) and N(9) in caffeine. The ordering theobromine > theophylline > caffeine site and theophylline < theobromine < caffeine according to increasing electric field gradient (EFG) at the N(1) and N(7) sites, respectively, reflects the changes in biological activity profile of compounds from the methylxanthines series (different pharmacological effects). This difference is elucidated on the basis of the ability to form intra- and intermolecular interactions (hydrogen bonds and π···π stacking interactions). The introduction of methyl groups to xanthine restricts the ability of nitrogen atoms to participate in strong hydrogen bonds; as a result, the dominating effect shifts from hydrogen bond (theobromine) to π···π stacking (caffeine). Substantial differences in the intermolecular interactions in stable forms of methylxanthines differing in methylation (site or number) were analyzed within the Hirshfeld

  2. Wireless power transfer based on magnetic quadrupole coupling in dielectric resonators

    NASA Astrophysics Data System (ADS)

    Song, Mingzhao; Iorsh, Ivan; Kapitanova, Polina; Nenasheva, Elizaveta; Belov, Pavel

    2016-01-01

    We numerically investigate a magnetic resonant wireless power transfer system based on high refractive index dielectric resonators. We propose to operate at magnetic quadrupole mode of the resonators to enlarge the efficiency due to minimization of ohmic and radiation losses. Numerical estimation predicts the 80% efficiency of the wireless power transfer (WPT) system operating at quadrupole mode at 300 MHz. Moreover, the system operating at magnetic quadrupole mode is capable of transferring power with 70% efficiency when the receiver rotates 90°. We verify the simulated results by experimental investigation of the WPT system based on microwave ceramic resonators (ɛ = 80 and tanδ = 10-4).

  3. 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.

  4. Simple expressions of the nuclear relaxation rate enhancement due to quadrupole nuclei in slowly tumbling molecules

    SciTech Connect

    Fries, Pascal H.; Belorizky, Elie

    2015-07-28

    For slowly tumbling entities or quasi-rigid lattices, we derive very simple analytical expressions of the quadrupole relaxation enhancement (QRE) of the longitudinal relaxation rate R{sub 1} of nuclear spins I due to their intramolecular magnetic dipolar coupling with quadrupole nuclei of arbitrary spins S ≥ 1. These expressions are obtained by using the adiabatic approximation for evaluating the time evolution operator of the quantum states of the quadrupole nuclei S. They are valid when the gyromagnetic ratio of the spin S is much smaller than that of the spin I. The theory predicts quadrupole resonant peaks in the dispersion curve of R{sub 1} vs magnetic field. The number, positions, relative intensities, Lorentzian shapes, and widths of these peaks are explained in terms of the following properties: the magnitude of the quadrupole Hamiltonian and the asymmetry parameter of the electric field gradient (EFG) acting on the spin S, the S-I inter-spin orientation with respect to the EFG principal axes, the rotational correlation time of the entity carrying the S–I pair, and/or the proper relaxation time of the spin S. The theory is first applied to protein amide protons undergoing dipolar coupling with fast-relaxing quadrupole {sup 14}N nuclei and mediating the QRE to the observed bulk water protons. The theoretical QRE agrees well with its experimental counterpart for various systems such as bovine pancreatic trypsin inhibitor and cartilages. The anomalous behaviour of the relaxation rate of protons in synthetic aluminium silicate imogolite nano-tubes due to the QRE of {sup 27}Al (S = 5/2) nuclei is also explained.

  5. Simple expressions of the nuclear relaxation rate enhancement due to quadrupole nuclei in slowly tumbling molecules

    NASA Astrophysics Data System (ADS)

    Fries, Pascal H.; Belorizky, Elie

    2015-07-01

    For slowly tumbling entities or quasi-rigid lattices, we derive very simple analytical expressions of the quadrupole relaxation enhancement (QRE) of the longitudinal relaxation rate R1 of nuclear spins I due to their intramolecular magnetic dipolar coupling with quadrupole nuclei of arbitrary spins S ≥ 1. These expressions are obtained by using the adiabatic approximation for evaluating the time evolution operator of the quantum states of the quadrupole nuclei S. They are valid when the gyromagnetic ratio of the spin S is much smaller than that of the spin I. The theory predicts quadrupole resonant peaks in the dispersion curve of R1 vs magnetic field. The number, positions, relative intensities, Lorentzian shapes, and widths of these peaks are explained in terms of the following properties: the magnitude of the quadrupole Hamiltonian and the asymmetry parameter of the electric field gradient (EFG) acting on the spin S, the S-I inter-spin orientation with respect to the EFG principal axes, the rotational correlation time of the entity carrying the S-I pair, and/or the proper relaxation time of the spin S. The theory is first applied to protein amide protons undergoing dipolar coupling with fast-relaxing quadrupole 14N nuclei and mediating the QRE to the observed bulk water protons. The theoretical QRE agrees well with its experimental counterpart for various systems such as bovine pancreatic trypsin inhibitor and cartilages. The anomalous behaviour of the relaxation rate of protons in synthetic aluminium silicate imogolite nano-tubes due to the QRE of 27Al (S = 5/2) nuclei is also explained.

  6. Quadrupole-induced resonant-particle transport in a pure electron plasma.

    PubMed

    Gilson, E P; Fajans, J

    2003-01-10

    Small transverse magnetic quadrupole fields sharply degrade the confinement of non-neutral plasmas held in Malmberg-Penning traps. For example, a quadrupole magnetic field of only 0.02 G/cm doubles the diffusion rate in a trap with a 100 G axial magnetic field. Larger quadrupole fields noticeably change the shape of the plasma. The transport is greatest at an orbital resonance. These results cast doubt on plans to use magnetic quadrupole neutral atom traps to confine antihydrogen atoms created in double-well positron/antiproton Malmberg-Penning traps.

  7. Dipole and Quadrupole Plasmon Resonances in Gold Nanoring Structures

    NASA Astrophysics Data System (ADS)

    Khosravi Khorashad, Larousse; Zhang, Hui; Roller, Eva-Maria; Liedl, Tim; Govorov, Alexander O.

    2014-03-01

    The quest for light manipulation in metallic nanostructures has grown greatly over the past decade to create novel optical devices for applications ranging from metamaterials and cloaking to optical sensing and plasmonic waveguides. Nanoring geometries, which are composed of metallic nanospheres, play an important role as the building blocks of plasmonic devices. We have shown that the plasmon resonance modes, which can be observed in absorption and scattering, not only depend on the dielectric function of the material, but also are strongly related to the size and shape of the structures and to the projection of the incident electromagnetic wave. By use of the finite element method, we have simulated ring geometries that are composed of different numbers of gold nanoparticles. The ring structures assembled experimentally have varying radii of nanoparticles and form symmetric and asymmetric geometries. This randomness in sizes and shapes influences the plasmonic spectrum of a ring, which consists of longitudinal and transverse plasmons and electric dipole and quadrupole modes. Moreover, the simulation predicts magnetic dipole radiation resulting from the circulation of current density. This work has been supported under the grant from Volkswagen Foundation

  8. The pygmy quadrupole resonance and neutron-skin modes in 124Sn

    NASA Astrophysics Data System (ADS)

    Spieker, M.; Tsoneva, N.; Derya, V.; Endres, J.; Savran, D.; Harakeh, M. N.; Harissopulos, S.; Herzberg, R.-D.; Lagoyannis, A.; Lenske, H.; Pietralla, N.; Popescu, L.; Scheck, M.; Schlüter, F.; Sonnabend, K.; Stoica, V. I.; Wörtche, H. J.; Zilges, A.

    2016-01-01

    We present an extensive experimental study of the recently predicted pygmy quadrupole resonance (PQR) in Sn isotopes, where complementary probes were used. In this study, (α ,α‧ γ) and (γ ,γ‧) experiments were performed on 124Sn. In both reactions, Jπ =2+ states below an excitation energy of 5 MeV were populated. The E2 strength integrated over the full transition densities could be extracted from the (γ ,γ‧) experiment, while the (α ,α‧ γ) experiment at the chosen kinematics strongly favors the excitation of surface modes because of the strong α-particle absorption in the nuclear interior. The excitation of such modes is in accordance with the quadrupole-type oscillation of the neutron skin predicted by a microscopic approach based on self-consistent density functional theory and the quasiparticle-phonon model (QPM). The newly determined γ-decay branching ratios hint at a non-statistical character of the E2 strength, as it has also been recently pointed out for the case of the pygmy dipole resonance (PDR). This allows us to distinguish between PQR-type and multiphonon excitations and, consequently, supports the recent first experimental indications of a PQR in 124Sn.

  9. Nuclear resonant spectroscopy

    NASA Astrophysics Data System (ADS)

    Sturhahn, Wolfgang

    2004-02-01

    Nuclear resonant scattering techniques with synchrotron radiation (SR) are introduced on a basic level. We focus on the theoretical background and on experimental aspects of two popular methods with a widening range of applications, nuclear resonant inelastic x-ray scattering and synchrotron Mössbauer spectroscopy. The inelastic method provides specific vibrational information, e.g., the phonon density of states. The Mössbauer method permits determination of hyperfine interactions. All nuclear resonance techniques take full advantage of the unique properties of SR: intensity, collimation, time structure, and polarization. As a result both methods discussed here have led to novel applications for materials under extreme conditions, proteins with biological functionality, and magnetic nanostructures.

  10. SP(6,R) Symmetry and the Giant Quadrupole Resonance in MAGNESIUM-24.

    NASA Astrophysics Data System (ADS)

    Reske, Edward John

    1984-06-01

    Microscopic nuclear calculations are approached by partitioning the many-nucleon Hilbert space as a direct sum of symplectic bands. Computational techniques and algorithms which utilize commutator methods, and which are more powerful than the more straight-forward purely shell-model approach, are developed for calculating the matrix elements of two-body operators within such an Sp(6,R) (R-HOOK) U(3) symmetry-adapted basis. These techniques may be generalized to n-body operators of any n. These computational tools are applied to the study of the Giant Quadrupole Resonance in ('24)Mg: the final calculation presented uses a microscopic Hamiltonian consisting of the kinetic energy plus the semi-realistic two-body Brink -Boeker B1 potential within a space consisting of three symplectic bands up to 6(H/2PI)(omega) total excitation.

  11. Negative coupling and coupling phase dispersion in a silicon quadrupole micro-racetrack resonator.

    PubMed

    Bachman, Daniel; Tsay, Alan; Van, Vien

    2015-07-27

    We report the first experimental study of the effects of coupling phase dispersion on the spectral response of a two-dimensionally coupled quadrupole micro-racetrack resonator. Negative coupling in the system is observed to manifest itself in the sharp stop band transition and deep extinction in the pseudo-elliptic filter response of the quadrupole. The results demonstrate the feasibility of realizing advanced silicon microring devices based on the 2D coupling topology with general complex coupling coefficients.

  12. Distal and proximal ligand interactions in heme proteins: Correlations between C-O and Fe-C vibrational frequencies, oxygen-17 and carbon-13 nuclear magnetic resonance chemical shifts, and oxygen-17 nuclear quadrupole coupling constants in C sup 17 O- and sup 13 CO-labeled species

    SciTech Connect

    Ki Deok Park; Guo, K.; Adebodun, F.; Chiu, M.L.; Sligar, S.G.; Oldfield, E. )

    1991-03-05

    The authors have obtained the oxygen-17 nuclear magnetic resonance (NMR) spectra of a variety of C{sup 17}O-labeled heme proteins, including sperm whale (Physeter catodon) myoglobin, two synthetic sperm whale myoglobin mutants (His E7 {yields} Val E7; His E7 {yields} Phe E7), adult human hemoglobin, rabbit (Oryctolagus cuniculus) hemoglobin, horseradish (Cochlearia armoracia) peroxidase isoenzymes A and C, and Caldariomyces fumago chloroperoxidase, in some cases as a function of pH, and have determined their isotropic {sup 17}O NMR chemical shifts, {delta}{sub i}, and spin-lattice relaxation times, T{sub 1}. They have also obtained similar results on a picket fence prophyrin. The results show an excellent correlation between the infrared C-O vibrational frequencies, {nu}(C-O), and {delta}{sub i}, between {nu}(C-O) and the {sup 17}O nuclear quadrupole coupling constant, and as expected between e{sup 2}qQ/h and {delta}{sub i}. The results suggest the IR and NMR measurements reflect the same interaction, which is thought to be primarily the degree of {pi}-back-bonding from Fe d to CO {pi}* orbitals, as outlined previously.

  13. Determination of nuclear quadrupole moments – An example of the synergy of ab initio calculations and microwave spectroscopy

    SciTech Connect

    Kellö, Vladimir

    2015-01-22

    Highly correlated scalar relativistic calculations of electric field gradients at nuclei in diatomic molecules in combination with accurate nuclear quadrupole coupling constants obtained from microwave spectroscopy are used for determination of nuclear quadrupole moments.

  14. Quadrupole lattice resonances in plasmonic crystal excited by cylindrical vector beams

    NASA Astrophysics Data System (ADS)

    Sakai, Kyosuke; Nomura, Kensuke; Yamamoto, Takeaki; Omura, Tatsuya; Sasaki, Keiji

    2016-10-01

    We report a scheme to exploit low radiative loss plasmonic resonance by combining a dark (subradiant) mode and a lattice resonance. We theoretically demonstrate that such dark-mode lattice resonances in periodic arrays of nanodisks or plasmonic crystals can be excited by vertically incident light beams. We investigate the excitation of lattice resonances in a finite sized, square-lattice plasmonic crystal by two types of cylindrical vector beams and a linearly polarized Gaussian beam. Quadrupole lattice resonances are excited by all three beams, and the largest peak intensity is obtained by using a specific type of cylindrical vector beam. Because of their lower radiative losses with many hotspots, the quadrupole lattice resonances in plasmonic crystal may pave the way for photonic research and applications that require strong light-matter interactions.

  15. Quadrupole lattice resonances in plasmonic crystal excited by cylindrical vector beams

    PubMed Central

    Sakai, Kyosuke; Nomura, Kensuke; Yamamoto, Takeaki; Omura, Tatsuya; Sasaki, Keiji

    2016-01-01

    We report a scheme to exploit low radiative loss plasmonic resonance by combining a dark (subradiant) mode and a lattice resonance. We theoretically demonstrate that such dark-mode lattice resonances in periodic arrays of nanodisks or plasmonic crystals can be excited by vertically incident light beams. We investigate the excitation of lattice resonances in a finite sized, square-lattice plasmonic crystal by two types of cylindrical vector beams and a linearly polarized Gaussian beam. Quadrupole lattice resonances are excited by all three beams, and the largest peak intensity is obtained by using a specific type of cylindrical vector beam. Because of their lower radiative losses with many hotspots, the quadrupole lattice resonances in plasmonic crystal may pave the way for photonic research and applications that require strong light-matter interactions. PMID:27734923

  16. Nuclear Magnetic Resonance Gyroscope

    NASA Astrophysics Data System (ADS)

    Larsen, Michael; Griffith, Robert; Bulatowicz, Michael

    2014-03-01

    The navigation grade micro Nuclear Magnetic Resonance Gyroscope (micro-NMRG) being developed by the Northrop Grumman Corporation (NGC) has concluded the fourth and final phase of the DARPA Navigation Grade Integrated Micro Gyro (NGIMG) program. Traditional MEMS gyros utilize springs as an inherent part of the sensing mechanism, leading to bias and scale factor sensitivity to acceleration and vibration. As a result, they have not met performance expectations in real world environments and to date have been limited to tactical grade applications. The Nuclear Magnetic Resonance Gyroscope (NMRG) utilizes the fixed precession rate of a nuclear spin in a constant magnetic field as an inertial reference for determining rotation. The nuclear spin precession rate sensitivity to acceleration and vibration is negligible for most applications. Therefore, the application of new micro and batch fabrication methods to NMRG technology holds great promise for navigation grade performance in a low cost and compact gyro. This presentation will describe the operational principles, design basics, and demonstrated performance of the NMRG including an overview of the NGC designs developed and demonstrated in the DARPA gyro development program.

  17. Nuclear Magnetic Resonance Gyroscope

    NASA Astrophysics Data System (ADS)

    Bulatowicz, Michael; Griffith, Robert; Larsen, Michael

    2014-03-01

    The navigation grade micro Nuclear Magnetic Resonance Gyroscope (micro-NMRG) being developed by the Northrop Grumman Corporation (NGC) has concluded the fourth and final phase of the DARPA Navigation Grade Integrated Micro Gyro (NGIMG) program. Traditional MEMS gyros utilize springs as an inherent part of the sensing mechanism, leading to bias and scale factor sensitivity to acceleration and vibration. As a result, they have not met performance expectations in real world environments and to date have been limited to tactical grade applications. The Nuclear Magnetic Resonance Gyroscope (NMRG) utilizes the fixed precession rate of a nuclear spin in a constant magnetic field as an inertial reference for determining rotation. The nuclear spin precession rate sensitivity to acceleration and vibration is negligible for most applications. Therefore, the application of new micro and batch fabrication methods to NMRG technology holds great promise for navigation grade performance in a low cost and compact gyro. This poster will describe the history, operational principles, design, and demonstrated performance of the NMRG including an overview of the NGC designs developed and demonstrated in the DARPA gyro development program.

  18. Nuclear Magnetic Resonance Gyroscope

    NASA Astrophysics Data System (ADS)

    Bulatowicz, Michael; Clark, Philip; Griffith, Robert; Larsen, Michael; Mirijanian, James

    2012-06-01

    The navigation grade micro Nuclear Magnetic Resonance Gyroscope (micro-NMRG) being developed by the Northrop Grumman Corporation is concluding the fourth and final phase of the DARPA Navigation Grade Integrated Micro Gyro (NGIMG) program. Traditional MEMS gyros utilize springs as an inherent part of the sensing mechanism, leading to bias and scale factor sensitivity to acceleration and vibration. As a result, they have not met performance expectations in real world environments and to date have been limited to tactical grade applications. The Nuclear Magnetic Resonance Gyroscope (NMRG) utilizes the fixed precession rate of a nuclear spin in a constant magnetic field as an inertial reference for determining rotation. The nuclear spin precession rate sensitivity to acceleration and vibration is negligible for most applications. Therefore, the application of new micro and batch fabrication methods to NMRG technology holds great promise for navigation grade performance in a low cost and compact gyro. This poster will describe the history, operational principles, and design basics of the NMRG including an overview of the NSD designs developed and demonstrated in the DARPA gyro development program. General performance results from phases 3 and 4 will also be presented.

  19. Noble Gas Detection Using Resonance Ionization Spectroscopy and a Quadrupole Mass Spectrometer

    NASA Astrophysics Data System (ADS)

    Chen, C. H.; Hurst, G. S.

    1983-10-01

    The technique of Resonance Ionization Spectroscopy (RIS) is being extended to develop a means for counting individual atoms of a selected isotope of a noble gas. In this method, lasers are used for RIS to obtain atomic species (Z) selectivity and a small quadrupole mass spectrometer provides isotopic (A) selectivity. A progress report on the objective of counting each atom of a particular isotope of a noble gas is given. Resonance ionization spectroscopy and its use for the detection of single atoms has been reviewed.' More recently, our efforts at ORNL have turned to the problem of direct counting of noble gas atoms2,3,4 as an alternative to decay counting of particular isotopes of noble gas species. For broader applications, the ORNL group is trying to develop a facility for counting a few rare gas atoms of a given isotopic variety in a sample. The detection of a small number of 81Kr atoms (<1000) is very important for groundwater dating, polar ice-cap dating, and nuclear waste disposal applications, and solar neutrino research. The ultimate goal is to count a small number (e.g., 100 to 1,000) of selected atoms having mass number A, even when mixed with 1012 or more atoms having mass number ± 1. The experimental schematic is shown in Figure 1. The concept for counting noble gas atoms with isotopic selectivity is to utilize a laser for ionizing atoms of a selected atomic

  20. Nuclear Magnetic Resonance Gyroscope

    NASA Astrophysics Data System (ADS)

    Larsen, Michael

    2011-05-01

    The navigation grade micro Nuclear Magnetic Resonance Gyroscope (micro-NMRG) being developed by the Northrop Grumman Corporation is currently in phase 4 of the DARPA Navigation Grade Integrated Micro Gyro (NGIMG) program. The micro-NMRG technology is pushing the boundaries of size, weight, power, and performance allowing new small platform applications of navigation grade Inertial Navigation System (INS) technology. Information on the historical development of the technology, basics of operation, task performance goals, application opportunities, and a phase 2 sample of earth rate measurement data will be presented. Funding Provided by the Defense Advanced Research Projects Agency (DARPA)

  1. nuclear magnetic resonance gyroscope

    SciTech Connect

    Karwacki, F. A.; Griffin, J.

    1985-04-02

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

  2. Nuclear Magnetic Resonance Gyroscope

    NASA Astrophysics Data System (ADS)

    Larsen, Michael; Bulatowicz, Michael; Clark, Philip; Griffith, Robert; Mirijanian, James; Pavell, James

    2015-05-01

    The Nuclear Magnetic Resonance Gyroscope (NMRG) is being developed by the Northrop Grumman Corporation (NGC). Cold and hot atom interferometer based gyroscopes have suffered from Size, Weight, and Power (SWaP) challenges and limits in bandwidth, scale factor stability, dead time, high rotation rate, vibration, and acceleration. NMRG utilizes the fixed precession rate of a nuclear spin in a constant magnetic field as a reference for determining rotation, providing continuous measurement, high bandwidth, stable scale factor, high rotation rate measurement, and low sensitivity to vibration and acceleration in a low SWaP package. The sensitivity to vibration has been partially tested and demonstrates no measured sensitivity within error bars. Real time closed loop implementation of the sensor significantly decreases environmental and systematic sensitivities and supports a compact and low power digital signal processing and control system. Therefore, the NMRG technology holds great promise for navigation grade performance in a low cost SWaP package. The poster will describe the history, operation, and design of the NMRG. General performance results will also be presented along with recent vibration test results.

  3. Structures and Nuclear Quadrupole Coupling Tensors of a Series of Chlorine-Containing Hydrocarbons

    NASA Astrophysics Data System (ADS)

    Dikkumbura, Asela S.; Webster, Erica R.; Dorris, Rachel E.; Peebles, Rebecca A.; Peebles, Sean A.; Seifert, Nathan A.; Pate, Brooks

    2016-06-01

    Rotational spectra for gauche-1,2-dichloroethane (12DCE), gauche-1-chloro-2-fluoroethane (1C2FE) and both anti- and gauche-2,3-dichloropropene (23DCP) have been observed using chirped-pulse Fourier-transform microwave (FTMW) spectroscopy in the 6-18 GHz region. Although the anti conformers for all three species are predicted to be more stable than the gauche forms, they are nonpolar (12DCE) or nearly nonpolar (predicted dipole components for anti-1C2FE: μ_a = 0.11 D, μ_b = 0.02 D and for anti-23DCP: μ_a = 0.25 D, μ_b = 0.02 D); nevertheless, it was also possible to observe and assign the spectrum of anti-23DCP. Assignments of parent spectra and 37Cl and 13C substituted isotopologues utilized predictions at the MP2/6-311++G(2d,2p) level and Pickett's SPCAT/SPFIT programs. For the weak anti-23DCP spectra, additional measurements also utilized a resonant-cavity FTMW spectrometer. Full chlorine nuclear quadrupole coupling tensors for gauche-12DCE and both anti- and gauche-23DCP have been diagonalized to allow comparison of coupling constants. Kraitchman's equations were used to determine r_s coordinates of isotopically substituted atoms and r_0 structures were also deduced for gauche conformers of 12DCE and 1C2FE. Structural details and chlorine nuclear quadrupole coupling constants of all three molecules will be compared, and effects of differing halogen substitution and carbon chain length on molecular properties will be evaluated.

  4. Quadrupole Collective Inertia in Nuclear Fission: Cranking Approximation

    SciTech Connect

    Baran, A.; Sheikh, J. A.; Dobaczewski, J.; Nazarewicz, Witold

    2011-01-01

    Collective mass tensor derived from the cranking approximation to the adiabatic time-dependent Hartree-Fock-Bogoliubov (ATDHFB) approach is compared with that obtained in the Gaussian Overlap Approximation (GOA) to the generator coordinate method. Illustrative calculations are carried out for one-dimensional quadrupole fission pathways in ^{256}Fm. It is shown that the collective mass exhibits strong variations with the quadrupole collective coordinate. These variations are related to the changes in the intrinsic shell structure. The differences between collective inertia obtained in cranking and perturbative cranking approximations to ATDHFB, and within GOA, are discussed.

  5. Dipole–quadrupole Förster resonance in cesium Rydberg gas

    NASA Astrophysics Data System (ADS)

    Maineult, Wilfried; Pelle, Bruno; Faoro, Riccardo; Arimondo, Ennio; Pillet, Pierre; Cheinet, Patrick

    2016-11-01

    The resonant energy transfer between two close particles, also known as Förster resonance in atomic or biological systems, is usually associated with dipole–dipole interaction. In Rydberg atoms, it is a widely used tool to enhance the interactions between particles. Here, we observe a resonant energy transfer between Rydberg atoms that cannot be attributed to a dipole–dipole interaction, owing to selection rules, and comes instead from an efficient dipole–quadrupole process. We compare the measured probability transfer with a theoretical model including quadrupolar terms and find very good agreement with our measurement. Further studies of those multipolar resonances should probe their dependences on various parameters (quantum numbers, relative orientation of the atoms), and may find some applications in quantum procedures where dipole–dipole resonance cannot be used, for instance where the states of interest have a difference in angular momentum of two.

  6. Nuclear quadrupole moment of 57Fe from microscopic nuclear and atomic calculations.

    PubMed

    Martínez-Pinedo, G; Schwerdtfeger, P; Caurier, E; Langanke, K; Nazarewicz, W; Söhnel, T

    2001-08-01

    The nuclear quadrupole moment (NQM) of the Ipi = 3/2(-) excited nuclear state of 57Fe at 14.41 keV, important in Mössbauer spectroscopy, is determined from the large-scale nuclear shell-model calculations for 54Fe, 57Fe, and also from the electronic ab initio and density functional theory calculations including solid state and electron correlation effects for the molecules Fe(CO)(5) and Fe(C5H5)(2). Both independent methods yield very similar results. The recommended value is 0.15(2) e b. The NQM of the isomeric 10+ in 54Fe has also been calculated. The new NQM values for 54Fe and 57Fe are consistent with the perturbed angular distribution data.

  7. Effects of Large Nuclear Quadrupoles on Dielectric Properties of Glasses at Very Low Temperatures

    NASA Astrophysics Data System (ADS)

    Luck, A.; Fleischmann, A.; Reiser, A.; Enss, C.

    2014-12-01

    The universal behaviour of amorphous solids at low temperatures, governed by atomic tunneling systems as described by the standard tunneling model, has long been a generally accepted fact. In the last years, however, measurements of dielectric two-pulse polarization echoes have revealed that nuclear quadrupole moments involved in atomic tunneling systems can cause specific material-dependent effects in magnetic fields. We have performed measurements of the dielectric properties of the two multicomponent glasses N-KZFS11 and HY-1, containing several percent of tantalum oxide and holmium oxide respectively. As 181Ta and 165Ho both carry very large nuclear quadrupole moments, these glasses are ideal candidates to study the influence of nuclear quadrupole moments on the properties of glasses at very low temperatures. Our measurements not only show unique dielectric behaviour in both glasses, but also differ significantly from various predictions of the standard tunneling model.

  8. The nuclear electric quadrupole moment of antimony from the molecular method.

    PubMed

    Haiduke, Roberto L A; da Silva, Albérico B F; Visscher, Lucas

    2006-08-14

    Relativistic Dirac-Coulomb (DC) Hartree-Fock calculations are employed to obtain the analytic electric field gradient (EFG) on the antimony nucleus in the SbN, SbP, SbF, and SbCl molecules. The electronic correlation contribution to the EFGs is included with the DC-CCSD(T) and DC-CCSD-T approaches, also in the four-component framework, using a finite-difference method. The total EFG results, along with the experimental nuclear quadrupole coupling constants from microwave spectroscopy, allow to derive the nuclear quadrupole moments of (121)Sb and (123)Sb, respectively, as -543(11) and -692(14) mb.

  9. An effect of nuclear electric quadrupole moments in thermonuclear fusion plasmas

    NASA Technical Reports Server (NTRS)

    De, B. R.; Srnka, L. J.

    1978-01-01

    Consideration of the nuclear electric quadrupole terms in the expression for the fusion Coulomb barrier suggests that this electrostatic barrier may be substantially modified from that calculated under the usual plasma assumption that the nuclei are electric monopoles. This effect is a result of the nonspherical potential shape and the spatial quantization of the nuclear spins of the fully stripped ions in the presence of a magnetic field. For monopole-quadrupole fuel cycles like p-B-11, the fusion cross-section may be substantially increased at low energies if the protons are injected at a small angle relative to the confining magnetic field.

  10. Degree of accuracy in determining the nuclear electric quadrupole moment of radium

    SciTech Connect

    Bieron, Jacek; Pyykkoe, Pekka

    2005-03-01

    The multiconfiguration Dirac-Hartree-Fock (MCDHF) model has been employed to calculate the atomic expectation values responsible for the hyperfine splittings of the 7s7p {sup 3}P{sub 1,2} and {sup 1}P{sub 1} levels of radium. Calculated electric field gradients, together with the experimental electric quadrupole hyperfine structure constants, allow us to extract a nuclear electric quadrupole moment Q({sup 223}Ra) of 1.21(0.03) barn. This value is in good agreement with the semiempirical determination based on neutral radium hyperfine and fine structure, but differs from the latest result from an alkali-like radium ion.

  11. Resonance excitation of ions stored in a quadrupole ion trap. Part IV. Theory of quadrupolar excitation

    NASA Astrophysics Data System (ADS)

    Alfred, Roland L.; Londry, Frank A.; March, Raymond E.

    1993-06-01

    A new theoretical treatment is presented for quadrupolar resonance excitation of ions stored in a quadrupole ion trap. When the ratio of the tickle voltage amplitude to that of the drive potential is small, the equation of ion motion can be expressed in the form of a perturbation series. Exact and approximate solutions to the first-order perturbation eqations are presented. Ion trajectories calculated from these solutions are compared with those calculated by numerical integration. The resonance conditions were found to correspond to a series of angular frequencies given by [omega]u,n = n + [beta]u - [infinity] < n < [infinity]. Some of these, [beta]z[Omega], (1 + [beta]z)[Omega](1 - [beta]z)[Omega] [beta],[Omega], had been observed previously in simulation studies.

  12. Simplest photonuclear reactions accompanied by the excitation of isovector giant dipole and quadrupole resonances: Semimicroscopic description

    SciTech Connect

    Tulupov, B. A.; Urin, M. H.

    2012-09-15

    A semimicroscopic approach based on the continuum version of the random-phase approximation (CRPA) and on a semiphenomenological inclusion of the fragmentation effect is applied to describing cross sections for photoabsorption and direct plus semidirect and inverse reactions accompanied by the excitation of isovector giant dipole and quadrupole resonances. In addition to the spinless part of the Landau-Migdal interaction and a partly self-consistent phenomenological mean field of the nucleus, that version of the approach which is used here takes into account isovector separable velocity-dependent forces, as well as the effect of the fragmentation shift of the giant-resonance energy. The results obtained by calculating various features of the aforementioned cross sections for a number of magic and semimagic medium-mass nuclei are compared with respective experimental data.

  13. Accurate determination of the nuclear quadrupole moment of xenon from the molecular method

    NASA Astrophysics Data System (ADS)

    Canella, Guilherme A.; Santiago, Régis T.; Haiduke, Roberto L. A.

    2016-09-01

    This study provides a new determination of the nuclear electric quadrupole moment (NQM) for 131Xe, which is achieved by the molecular method. Dirac-Coulomb Coupled Cluster calculations with a Gaunt correction (DC+G-CC) of electric field gradients (EFGs) and experimental nuclear quadrupole coupling constants of six molecular systems (XeH+, XeCuF, XeCuCl, XeAgF, XeAgCl and XeAuF) were considered. The best NQM obtained by our DC+G-CCSD-T EFGs was -114.6(1.1) mbarn, which is recommended as the new reference value for this nuclide given the high level electron structure calculations done here.

  14. Fine structure of the isoscalar giant quadrupole resonance in 28Si and 27Al

    NASA Astrophysics Data System (ADS)

    Usman, I. T.; Buthelezi, Z.; Carter, J.; Cooper, G. R. J.; Fearick, R. W.; Förtsch, S. V.; Fujita, H.; Fujita, Y.; von Neumann-Cosel, P.; Neveling, R.; Papakonstantinou, P.; Pysmenetska, I.; Richter, A.; Roth, R.; Sideras-Haddad, E.; Smit, F. D.

    2016-08-01

    The isoscalar giant quadrupole resonance in 28Si and 27Al has been investigated with high-energy-resolution proton inelastic scattering at Ep=200 MeV and at scattering angles close to the maximum of Δ L =2 angular distributions with the K600 magnetic spectrometer of iThemba LABS, South Africa. Characteristic scales are extracted from the observed fine structure with a wavelet analysis and compared for 28Si with random-phase approximation and second random phase approximation calculations with an interaction derived from the Argonne V18 potential by a unitary transformation. A recent extension of the method to deformed nuclei provides the best description of the data, suggesting the significance of Landau damping.

  15. Fluctuation properties of the strength function associated with the giant quadrupole resonance in {sup 208}Pb

    SciTech Connect

    Aiba, Hirokazu; Matsuo, Masayuki; Nishizaki, Shigeru; Suzuki, Toru

    2011-02-15

    We performed fluctuation analysis by means of the local scaling dimension for the strength function of the isoscalar (IS) giant quadrupole resonance (GQR) in {sup 208}Pb where the strength function is obtained by the shell model calculation including 1p1h and 2p2h configurations. It is found that at almost all energy scales, fluctuation of the strength function obeys the Gaussian orthogonal ensemble (GOE) random matrix theory limit. This is contrasted with the results for the GQR in {sup 40}Ca, where at the intermediate energy scale of about 1.7 MeV, a deviation from the GOE limit was detected. It is found that the physical origin for this different behavior of the local scaling dimension is ascribed to the difference in the properties of the damping process.

  16. Analytical continuation from bound to resonant states in the Dirac equation with quadrupole-deformed potentials

    NASA Astrophysics Data System (ADS)

    Xu, Xu-Dong; Zhang, Shi-Sheng; Signoracci, A. J.; Smith, M. S.; Li, Z. P.

    2015-08-01

    Background: Resonances with pronounced single-particle characteristics are crucial for quantitative descriptions of exotic nuclei near and beyond the drip lines, and often impact halo formation and nucleon decay processes. Since the majority of nuclei are deformed, the interplay between deformation and orbital structure near threshold can lead to improved descriptions of exotic nuclei. Purpose: Develop a method to study single-particle resonant orbital structure in the Dirac equation with a quadrupole-deformed Woods-Saxon potential. Determine the structure evolution of bound and resonant levels with deformation in this scheme, and examine the impact on halo formation in loosely bound systems, with a focus on the recent halo candidate nucleus 37Mg. Method: Analytical continuation of the coupling constant (ACCC) method is developed on the basis of the Dirac equation with a deformed Woods-Saxon potential. The scalar and vector terms in the deformed potential are determined by the energies of the valence neutron and nearby orbitals, which are extracted from a self-consistent relativistic Hartree-Bogoliubov (RHB) calculation with the PC-PK1 density functional. Results: We compare the energies and widths of resonant orbitals in the recent halo nucleus candidate 37Mg using the ACCC method based on the Dirac coupled-channel equations with those determined from the scattering phase shift (SPS) method. It is found that the results from the two methods agree well for narrow resonances, whereas the SPS method fails for broad resonances. Nilsson levels for bound and resonant orbitals from the ACCC method are calculated over a wide range of deformations and show some decisive hints of halo formation in 37Mg. Conclusions: In our ACCC model for deformed potentials in the coupled-channel Dirac equations, the crossing of the configuration 1 /2 [321 ] and 5 /2 [312 ] orbitals at a deformation of approximately 0.5 enhances the probability to occupy the 1 /2 [321 ] orbital coming from

  17. Electric quadrupole polarizabilities of nuclear magnetic shielding in some small molecules.

    PubMed

    Ferraro, M B; Caputo, M C; Pagola, G I; Lazzeretti, P

    2008-01-28

    Computational procedures, based on (i) the Ramsey common origin approach and (ii) the continuous transformation of the origin of the quantum mechanical current density-diamagnetic zero (CTOCD-DZ), were applied at the Hartree-Fock level to determine electric quadrupole polarizabilities of nuclear magnetic shielding for molecules in the presence of a nonuniform electric field with a uniform gradient. The quadrupole polarizabilities depend on the origin of the coordinate system, but values of the magnetic field induced at a reference nucleus, determined via the CTOCD-DZ approach, are origin independent for any calculations relying on the algebraic approximation, irrespective of size and quality of the (gaugeless) basis set employed. On the other hand, theoretical estimates of the induced magnetic field obtained by single-origin methods are translationally invariant only in the limit of complete basis sets. Calculations of electric quadrupole polarizabilities of nuclear magnetic shielding are reported for H(2), HF, H(2)O, NH(3), and CH(4) molecules.

  18. Nuclear Magnetic Dipole and Electric Quadrupole Moments: Their Measurement and Tabulation as Accessible Data

    SciTech Connect

    Stone, N. J.

    2015-09-15

    The most recent tabulations of nuclear magnetic dipole and electric quadrupole moments have been prepared and published by the Nuclear Data Section of the IAEA, Vienna [N. J. Stone, Report No. INDC(NDS)-0650 (2013); Report No. INDC(NDS)-0658 (2014)]. The first of these is a table of recommended quadrupole moments for all isotopes in which all experimental results are made consistent with a limited number of adopted standards for each element; the second is a combined listing of all measurements of both moments. Both tables cover all isotopes and energy levels. In this paper, the considerations relevant to the preparation of both tables are described, together with observations as to the importance and (where appropriate) application of necessary corrections to achieve the “best” values. Some discussion of experimental methods is included with emphasis on their precision. The aim of the published quadrupole moment table is to provide a standard reference in which the value given for each moment is the best available and for which full provenance is given. A table of recommended magnetic dipole moments is in preparation, with the same objective in view.

  19. Evanescent Waves Nuclear Magnetic Resonance

    PubMed Central

    Halidi, El Mohamed; Nativel, Eric; Akel, Mohamad; Kenouche, Samir; Coillot, Christophe; Alibert, Eric; Jabakhanji, Bilal; Schimpf, Remy; Zanca, Michel; Stein, Paul; Goze-Bac, Christophe

    2016-01-01

    Nuclear Magnetic Resonance spectroscopy and imaging can be classified as inductive techniques working in the near- to far-field regimes. We investigate an alternative capacitive detection with the use of micrometer sized probes positioned at sub wavelength distances of the sample in order to characterize and model evanescent electromagnetic fields originating from NMR phenomenon. We report that in this experimental configuration the available NMR signal is one order of magnitude larger and follows an exponential decay inversely proportional to the size of the emitters. Those investigations open a new road to a better understanding of the evanescent waves component in NMR with the opportunity to perform localized spectroscopy and imaging. PMID:26751800

  20. Evanescent Waves Nuclear Magnetic Resonance.

    PubMed

    Halidi, El Mohamed; Nativel, Eric; Akel, Mohamad; Kenouche, Samir; Coillot, Christophe; Alibert, Eric; Jabakhanji, Bilal; Schimpf, Remy; Zanca, Michel; Stein, Paul; Goze-Bac, Christophe

    2016-01-01

    Nuclear Magnetic Resonance spectroscopy and imaging can be classified as inductive techniques working in the near- to far-field regimes. We investigate an alternative capacitive detection with the use of micrometer sized probes positioned at sub wavelength distances of the sample in order to characterize and model evanescent electromagnetic fields originating from NMR phenomenon. We report that in this experimental configuration the available NMR signal is one order of magnitude larger and follows an exponential decay inversely proportional to the size of the emitters. Those investigations open a new road to a better understanding of the evanescent waves component in NMR with the opportunity to perform localized spectroscopy and imaging.

  1. Collinear laser spectroscopy of atomic cadmium. Extraction of nuclear magnetic dipole and electric quadrupole moments

    NASA Astrophysics Data System (ADS)

    Frömmgen, Nadja; Balabanski, Dimiter L.; Bissell, Mark L.; Bieroń, Jacek; Blaum, Klaus; Cheal, Bradley; Flanagan, Kieran; Fritzsche, Stephan; Geppert, Christopher; Hammen, Michael; Kowalska, Magdalena; Kreim, Kim; Krieger, Andreas; Neugart, Rainer; Neyens, Gerda; Rajabali, Mustafa M.; Nörtershäuser, Wilfried; Papuga, Jasna; Yordanov, Deyan T.

    2015-06-01

    Hyperfine structure A and B factors of the atomic 5 s5 p 3P2 → 5 s6 s 3S1 transition are determined from collinear laser spectroscopy data of 107-123Cd and 111 m-123 m Cd. Nuclear magnetic moments and electric quadrupole moments are extracted using reference dipole moments and calculated electric field gradients, respectively. The hyperfine structure anomaly for isotopes with s 1/2 and d 5/2 nuclear ground states and isomeric h 11/2 states is evaluated and a linear relationship is observed for all nuclear states except s 1/2. This corresponds to the Moskowitz-Lombardi rule that was established in the mercury region of the nuclear chart but in the case of cadmium the slope is distinctively smaller than for mercury. In total four atomic and ionic levels were analyzed and all of them exhibit a similar behaviour. The electric field gradient for the atomic 5 s5 p 3P2 level is derived from multi-configuration Dirac-Hartree-Fock calculations in order to evaluate the spectroscopic nuclear quadrupole moments. The results are consistent with those obtained in an ionic transition and based on a similar calculation.

  2. 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.

  3. First Principles Study of Nuclear Quadrupole Interactions in Single and Double Chain DNA and Solid Nucleobases

    NASA Astrophysics Data System (ADS)

    Das, T. P.; Pink, R. H.; Badu, S. R.; Dubey, Archana; Scheicher, R. H.; Saha, H. P.; Chow, Lee; Huang, M. B.

    2009-03-01

    Nuclear Quadrupole Interactions (NQI) of ^17O, ^14N and ^2H nuclei have been studied for free nucleobases and nucleobases in single strand and double strand DNA and in solid state. Our first-principles investigations were carried out using the Gaussian 2003 set of programs to implement the Hartree-Fock procedure combined with many-body effects included using many-body perturbation theory. As expected for NQI in general, many-body effects are found to be small. Results will be presented for the quadrupole coupling constants (e^2qQ) and asymmetry parameters (η) for the nucleobases in the various environments. Trends in e^2qQ and η in the different environments will be discussed. In the case of the solid nucleobases, comparisons will be made with available experimental data [1] for ^17O nuclei.[3pt] [1] Gang Wu et al., J. Am. Chem. Soc. 124, 1768 (2002)

  4. Global investigation of the fine structure of the isoscalar giant quadrupole resonance

    SciTech Connect

    Shevchenko, A.; Burda, O.; Kalmykov, Y.; Neumann-Cosel, P. von; Ponomarev, V. Yu.; Richter, A.; Wambach, J.; Carter, J.; Sideras-Haddad, E.; Cooper, G. R. J.; Fearick, R. W.; Foertsch, S. V.; Lawrie, J. J.; Neveling, R.; Smit, F. D.; Fujita, H.; Fujita, Y.; Lacroix, D.

    2009-04-15

    Fine structure in the region of the isoscalar giant quadrupole resonance (ISGQR) in {sup 58}Ni, {sup 89}Y, {sup 90}Zr, {sup 120}Sn, {sup 166}Er, and {sup 208}Pb has been observed in high-energy-resolution ({delta}E{sub 1/2}{approx_equal}35-50 keV) inelastic proton scattering measurements at E{sub 0}=200 MeV at iThemba LABS. Calculations of the corresponding quadrupole excitation strength functions performed within models based on the random-phase approximation (RPA) reveal similar fine structure when the mixing of one-particle one-hole states with two-particle two-hole states is taken into account. A detailed comparison of the experimental data is made with results from the quasiparticle-phonon model (QPM) and the extended time-dependent Hartree-Fock (ETDHF) method. For {sup 208}Pb, additional theoretical results from second RPA and the extended theory of finite Fermi systems (ETFFS) are discussed. A continuous wavelet analysis of the experimental and the calculated spectra is used to extract dominant scales characterizing the fine structure. Although the calculations agree with qualitative features of these scales, considerable differences are found between the model and experimental results and amongst different models. Within the framework of the QPM and ETDHF calculations it is possible to decompose the model spaces into subspaces approximately corresponding to different damping mechanisms. It is demonstrated that characteristic scales mainly arise from the collective coupling of the ISGQR to low-energy surface vibrations.

  5. Communication: Nuclear quadrupole moment-induced Cotton-Mouton effect in noble gas atoms

    SciTech Connect

    Fu, Li-juan; Vaara, Juha; Rizzo, Antonio

    2013-11-14

    New, high-sensitivity and high-resolution spectroscopic and imaging methods may be developed by exploiting nuclear magneto-optic effects. A first-principles electronic structure formulation of nuclear electric quadrupole moment-induced Cotton-Mouton effect (NQCME) is presented for closed-shell atoms. In NQCME, aligned quadrupole moments alter the index of refraction of the medium along with and perpendicular to the direction of nuclear alignment. The roles of basis-set convergence, electron correlation, and relativistic effects are investigated for three quadrupolar noble gas isotopes: {sup 21}Ne, {sup 83}Kr, and {sup 131}Xe. The magnitude of the resulting ellipticities is predicted to be 10{sup −4}–10{sup −6} rad/(M cm) for fully spin-polarized nuclei. These should be detectable in the Voigt setup. Particularly interesting is the case of {sup 131}Xe, in which a high degree of spin polarization can be achieved via spin-exchange optical hyperpolarization.

  6. Demonstration of an ultrasensitive refractive-index plasmonic sensor by enabling its quadrupole resonance in phase interrogation.

    PubMed

    Lee, Hsin-Cheng; Li, Chung-Tien; Chen, How-Foo; Yen, Ta-Jen

    2015-11-15

    We present an ultrasensitive plasmonic sensing system by introducing a nanostructured X-shaped plasmonic sensor (XPS) and measuring its localized optical properties in phase interrogation. Our tailored XPS exhibits two major resonant modes of a low-order dipole and a high-order quadrupole, between which the quadrupole resonance allows an ultrahigh sensitivity, due to its higher quality factor. Furthermore, we design an in-house common-path phase-interrogation system, in contrast to conventional wavelength-interrogation methods, to achieve greater sensing capability. The experimental measurement shows that the sensing resolution of the XPS reaches 1.15×10(-6) RIU, not only two orders of magnitude greater than the result of the controlled extinction measurement (i.e., 9.90×10(-5) RIU), but also superior than current reported plasmonic sensors.

  7. Demonstration of an ultrasensitive refractive-index plasmonic sensor by enabling its quadrupole resonance in phase interrogation.

    PubMed

    Lee, Hsin-Cheng; Li, Chung-Tien; Chen, How-Foo; Yen, Ta-Jen

    2015-11-15

    We present an ultrasensitive plasmonic sensing system by introducing a nanostructured X-shaped plasmonic sensor (XPS) and measuring its localized optical properties in phase interrogation. Our tailored XPS exhibits two major resonant modes of a low-order dipole and a high-order quadrupole, between which the quadrupole resonance allows an ultrahigh sensitivity, due to its higher quality factor. Furthermore, we design an in-house common-path phase-interrogation system, in contrast to conventional wavelength-interrogation methods, to achieve greater sensing capability. The experimental measurement shows that the sensing resolution of the XPS reaches 1.15×10(-6) RIU, not only two orders of magnitude greater than the result of the controlled extinction measurement (i.e., 9.90×10(-5) RIU), but also superior than current reported plasmonic sensors. PMID:26565822

  8. Introduction to Nuclear Magnetic Resonance

    NASA Technical Reports Server (NTRS)

    Manatt, Stanley L.

    1985-01-01

    The purpose of this paper is to try to give a short overview of what the status is on nuclear magnetic resonance (NMR). It's a subject where one really has to spend some time to look at the physics in detail to develop a proper working understanding. I feel it's not appropriate to present to you density matrices, Hamiltonians of all sorts, and differential equations representing the motion of spins. I'm really going to present some history and status, and show a few very simple concepts involved in NMR. It is a form of radio frequency spectroscopy and there are a great number of nuclei that can be studied very usefully with the technique. NMR requires a magnet, a r.f. transmitter/receiver system, and a data acquisition system.

  9. Wide-range nuclear magnetic resonance detector

    NASA Technical Reports Server (NTRS)

    Sturman, J. C.; Jirberg, R. J.

    1972-01-01

    Compact and easy to use solid state nuclear magnetic resonance detector is designed for measuring field strength to 20 teslas in cryogenically cooled magnets. Extremely low noise and high sensitivity make detector applicable to nearly all types of analytical nuclear magnetic resonance measurements and can be used in high temperature and radiation environments.

  10. Hartree-Fock Cluster Study of Electronic Structures and Nuclear Quadrupole Interactions in Solid Nucleobases.

    NASA Astrophysics Data System (ADS)

    Scheicher, R. H.; Dubey, Archana; Badu, S. R.; Saha, H. P.; Pink, R. H.; Nagamine, K.; Torikai, E.; Chow, Lee; Das, T. P.

    2008-03-01

    In recent work [1] we have studied nucleobases attached to a CH3 group to simulate the influence of their binding to the sugar rings and the phosphate groups in DNA and RNA and the effect of this binding on the nuclear quadrupole interactions of ^14N, ^17O and ^2H nuclei. Our results from this work have indicated that for ^17O, the binding to the CH3 group moves our results from the free nucleobases closer to the experimentally observed data [2] in the solid nucleobases. We are now investigating the solid nucleobases by the first --principles Hartree-Fock cluster procedure that we have employed earlier for the halogen molecular solids [3]. Our results for the binding energy of an imidazole molecule in the molecular solid system and the ^14N, ^17O and ^2H nuclear quadrupole interaction parameters will be presented. [1] T.P. Das et al (at this APS meeting), [2] Gang Wu et al, J. Am.Chem. Soc. 124, 1768(2002). [3] M.M. Aryal et al Hyperfine Interactions (to be published).

  11. Discriminating the structure of exo-2-aminonorbornane using nuclear quadrupole coupling interactions.

    PubMed

    Écija, Patricia; Cocinero, Emilio J; Lesarri, Alberto; Millán, Judith; Basterretxea, Francisco; Fernández, José A; Castaño, Fernando

    2011-04-28

    The intrinsic conformational and structural properties of the bicycle exo-2-aminonorbornane have been probed in a supersonic jet expansion using Fourier-transform microwave (FT-MW) spectroscopy and quantum chemical calculations. The rotational spectrum revealed two different conformers arising from the internal rotation of the amino group, exhibiting small (MHz) hyperfine patterns originated by the (14)N nuclear quadrupole coupling interaction. Complementary ab initio (MP2) and DFT (B3LYP and M05-2X) calculations provided comparative predictions for the structural properties, rotational and centrifugal distortion data, hyperfine parameters, and isomerization barriers. Due to the similarity of the rotational constants, the structural assignment of the observed rotamers and the calculation of the torsion angles of the amino group were based on the conformational dependence of the (14)N nuclear quadrupole coupling hyperfine tensor. In the most stable conformation (ss), the two amino N-H bonds are staggered with respect to the adjacent C-H bond. In the second conformer (st), only one of the N-H bonds is staggered and the other is trans. A third predicted conformer (ts) was not detected, consistent with a predicted conformational relaxation to conformer ss through a low barrier of 5.2 kJ mol(-1).

  12. An approximate analytical expression for the nuclear quadrupole transverse relaxation rate of half-integer spins in liquids.

    PubMed

    Wu, Gang

    2016-08-01

    The nuclear quadrupole transverse relaxation process of half-integer spins in liquid samples is known to exhibit multi-exponential behaviors. Within the framework of Redfield's relaxation theory, exact analytical expressions for describing such a process exist only for spin-3/2 nuclei. As a result, analyses of nuclear quadrupole transverse relaxation data for half-integer quadrupolar nuclei with spin >3/2 must rely on numerical diagonalization of the Redfield relaxation matrix over the entire motional range. In this work we propose an approximate analytical expression that can be used to analyze nuclear quadrupole transverse relaxation data of any half-integer spin in liquids over the entire motional range. The proposed equation yields results that are in excellent agreement with the exact numerical calculations. PMID:27343483

  13. Electron-nuclear double resonance on copper (II) tetraimidazole

    NASA Astrophysics Data System (ADS)

    Van Camp, Harlan L.; Sands, Richard H.; Fee, James A.

    1981-09-01

    We have investigated the electron-nuclear double resonance (ENDOR) from frozen aqueous solutions of 65Cu++(imidazole)4, 65Cu++ (imidazole-15N)4, and 65Cu++(imidazole-Dn)4, where n = 1, 2, 3, and 4 for selectively deuterated imidazole. We have observed ENDOR associated with the imidazole protons and the two imidazole nitrogens. The selective deuteration has allowed us to attempt identification of the weakly coupled protons responsible for the ENDOR spectrum, and a comparison of the overall line shape of that spectrum taken at two extreme points of the EPR spectrum suggests that some of the imidazole planes are tilted with respect to the plane of the complex. The ENDOR arising from the nitrogen nearest the copper is primarily isotropic with A(g⊥) = 41.6±1.5 MHz and A(g∥) = 39.8±1.5 MHz. The resonance shows little structure and seems consistent with a picture that requires some inequivalence among the various imidazoles. The remote nitrogen ENDOR reveals both hyperfine and quadrupole effects with approximately isotropic A(14N) = 1.79 MHz, Qz'z'?0.360 MHz, and Qx'x'y'x'?0.349 MHz. These values are in agreement with the results of the nuclear modulation effect [J. Chem. Phys. 69, 4921 (1978)]. The values for the quadrupole constants are thought to be accurate within 10% and are the same as are found in free imidazole. It is also demonstrated that, in this instance, ENDOR and the nuclear modulation effect are complementary in that they have each provided different parts of the same hyperfine spectrum.

  14. Nuclear resonant scattering of synchrotron radiation by 187Os

    NASA Astrophysics Data System (ADS)

    Bessas, D.; Sergueev, I.; Merkel, D. G.; Chumakov, A. I.; Rüffer, R.; Jafari, A.; Kishimoto, S.; Wolny, J. A.; Schünemann, V.; Needham, R. J.; Sadler, P. J.; Hermann, R. P.

    2015-06-01

    We performed nuclear forward and inelastic scattering of synchrotron radiation by elemental Os utilizing the nuclear excited state of 187Os which is otherwise inaccessible using any practical radioactive decay process. The lifetime of the excited state, 3.06 (8 )ns , and the energy of the transition, 9.778 (3 )keV , are refined. The nuclear quadrupole moment of the excited state, Q3 /2=1.46 (10 ) b , is determined. The density of phonon states for elemental Os, which is herein experimentally determined, suggests that the Os lattice is a model for the lattice dynamics of hcp-Fe. The combination of the low energy of the nuclear transition and the large nuclear mass leads to a high recoil free fraction, fL M=0.95 (1 ) , at room temperature, a large value that strongly supports the viability of nuclear resonance scattering as a reliable method to study electronic, magnetic, and elastic properties of Os compounds, including Os organometallics.

  15. Contemporary research with nuclear resonance fluorescence at the S-DALINAC

    SciTech Connect

    Zweidinger, M.; Beck, T.; Beller, J.; Gayer, U.; Mertes, L.; Pai, H.; Pietralla, N.; Ries, P.; Romig, C.; Werner, V.

    2015-02-24

    In the last decades many nuclear resonance fluorescence experiments aiming for low-lying dipole excitations were performed at the Darmstadt High Intensity Photon Setup at S-DALINAC facility. On the electric dipole side, quadrupole-octupole coupled states and the Pygmy Dipole Resonance are of particular interest. On the magnetic dipole side, the so-called scissors mode is in the focus of interest. Furthermore, using the method of resonant self absorption, the decay behavior of J{sup π} = 1{sup −} states was investigated in {sup 140}Ce.

  16. Statistical signal processing for detection of buried land mines using quadrupole resonance

    NASA Astrophysics Data System (ADS)

    Liu, Feng; Tantum, Stacy L.; Collins, Leslie M.; Carin, Lawrence

    2000-08-01

    Quadrupole resonance (QR) is a technique that discriminates mines from clutter by exploiting unique properties of explosives, rather than the attributes of the mine that exist in many forms of anthropic clutter. After exciting the explosive with a properly designed electromagnetic-induction (EMI) system, one attempts to sense late-time spin echoes, which are characterized by radiation at particular frequencies. It is this narrow-band radiation that indicates the present of explosives, since this effect is not seen in most clutter, both natural and anthropic. However, explosives detection via QR is complicated by several practical issues. First, the late-time radiation is often very weak, particularly for TNT, and therefore the signal- to-noise ratio must be high for extracting the QR response. Further, the frequency at which the radiation occurs is often a strong function of the background environment, and therefore in practice the QR radiation frequency is not known a priori. Also, at frequencies of interest, there is a significant amount of background radiation, which induces radio frequency interference (RFI). In addition, the response properties of the system are sensitive to the height of the sensor above the ground, and the QR sensor effectively becomes 'de-tuned'. Finally, present QR systems cannot detect the explosive in metal-cased mines, thus the system and associated signal processing must be extended to also operate as a metal detector. Previously, we have shown that adaptive noise cancellation techniques, in particular, the least-mean-square algorithm, provide an effective means of RFI mitigation and can dramatically improve QR detection. In this paper we discuss several signal processing tools we have developed to further enhance the utility of QR explosives detection. In particular, with regard to the uncertainties concerning the background environment and sensor height, we explore statistical signal processing strategies to rigorously account for

  17. Electron Paramagnetic Resonance -- Nuclear Magnetic Resonance Three Axis Vector Magnetometer

    NASA Astrophysics Data System (ADS)

    Bulatowicz, Michael; Clark, Philip; Griffith, Robert; Larsen, Michael; Mirijanian, James

    2012-06-01

    The Northrop Grumman Corporation is leveraging the technology developed for the Nuclear Magnetic Resonance Gyroscope (NMRG) to build a combined Electron Paramagnetic Resonance -- Nuclear Magnetic Resonance (EPR-NMR) magnetometer. The EPR-NMR approach provides a high bandwidth and high sensitivity simultaneous measurement of all three vector components of the magnetic field averaged over the small volume of the sensor's one vapor cell. This poster will describe the history, operational principles, and design basics of the EPR-NMR magnetometer including an overview of the NSD designs developed and demonstrated to date. General performance results will also be presented.

  18. Prototype explosives detection system based on nuclear resonance absorption in nitrogen

    SciTech Connect

    Morgado, R.E.; Arnone, G.J.; Cappiello, C.C.

    1996-05-01

    A laboratory prototype system has been developed for the experimental evaluation of an explosives detection technique based on nuclear resonance absorption of gamma rays in nitrogen. Major subsystems include a radiofrequency quadrupole proton accelerator and associated beam transport system, a high-power gamma-ray production target, an airline-luggage tomographic inspection system, and an image- processing/detection-alarm subsystem. The detection system performance, based on a limited experimental test, is reported.

  19. Nuclear Quadrupole Coupling Constants of Two Chemically Distinct Nitrogen Atoms in 4-Aminobenzonitrile

    PubMed Central

    2014-01-01

    The rotational spectrum of 4-aminobenzonitrile in the gas phase between 2 and 8.5 GHz is reported. Due to the two chemically distinct nitrogen atoms, the observed transitions showed a rich hyperfine structure. From the determination of the nuclear quadrupole coupling constants, information about the electronic environment of these atoms could be inferred. The results are compared to data for related molecules, especially with respect to the absence of dual fluorescence in 4-aminobenzonitrile. In addition, the two-photon ionization spectrum of this molecule was recorded using a time-of-flight mass spectrometer integrated into the setup. This new experimental apparatus is presented here for the first time. PMID:24911139

  20. Quadrupole moments in chiral material DyFe3(BO3)4 observed by resonant x-ray diffraction

    NASA Astrophysics Data System (ADS)

    Nakajima, Hiroshi; Usui, Tomoyasu; Joly, Yves; Suzuki, Motohiro; Wakabayashi, Yusuke; Kimura, Tsuyoshi; Tanaka, Yoshikazu

    2016-04-01

    By means of circularly polarized x rays at the Dy L3 and Fe K absorption edges, the chiral structure of the electric quadrupole was investigated for a single crystal of DyFe3(BO3)4, in which both Dy and Fe ions exhibit a spiral arrangement. The integrated intensity of the resonant x-ray diffraction of space-group forbidden reflections 004 and 005 is interpreted within the electric dipole transitions from Dy 2 p3/2 to 5 d and Fe 1 s to 4 p , respectively. We have confirmed that the handedness of the crystal observed at Dy L3 and Fe K edges is consistent with that observed at Dy M5 edge reported in a previous study. The electric quadrupole moments of Dy 5 d and Fe 4 p are derived by analyzing the azimuth scans of the diffracted intensity. The temperature profiles of the integrated intensity of 004 at the Dy L3 and the Fe K edges are similar to those of Dy-O and Fe-O bond lengths, while the temperature dependence at the Dy M5 edge does not match the bond-length behavior. The results indicate that the helix chiral orientations of quadrupole moments due to Dy 5 d and Fe 4 p electrons are more strongly coupled to the ligands states than Dy 4 f electrons.

  1. An improved nuclear magnetic resonance spectrometer

    NASA Technical Reports Server (NTRS)

    Elleman, D. D.; Manatt, S. L.

    1967-01-01

    Cylindrical sample container provides a high degree of nuclear stabilization to a nuclear magnetic resonance /nmr/ spectrometer. It is placed coaxially about the nmr insert and contains reference sample that gives a signal suitable for locking the field and frequency of an nmr spectrometer with a simple audio modulation system.

  2. Nuclear quadrupole moment-induced Cotton-Mouton effect in molecules

    SciTech Connect

    Fu, Li-juan E-mail: juha.vaara@iki.fi; Vaara, Juha E-mail: juha.vaara@iki.fi

    2014-01-14

    Nuclear magneto-optic effects could make important contributions to novel, high-sensitivity, and high-resolution spectroscopic and imaging methods that provide nuclear site-specific structural and dynamic information on molecular and materials systems. Here we present a first-principles electronic structure formulation of nuclear quadrupole moment-induced Cotton-Mouton effect in terms of response theory, as well as ab initio and density-functional theory calculations of this phenomenon for a series of molecular liquids: H{sub 2}O, CH{sub 3}NO{sub 2}, CH{sub 3}CH{sub 2}OH, C{sub 6}H{sub 6}, C{sub 6}H{sub 12} (cyclohexane), HI, XeF{sub 2}, WF{sub 5}Cl, and Pt(C{sub 2}dtp){sub 2}. The roles of basis-set convergence, electron correlation, and relativistic effects are discussed. The estimated order of magnitude of the overall ellipticities induced to linearly polarized light is 10{sup −3}–10{sup −7} rad/(M cm) for fully spin polarized nuclei. The cases with the largest presently obtained ellipticities should be detectable with modern instrumentation in the Voigt magneto-optic setup, particularly for the heavy nuclei.

  3. Nuclear magnetic resonance contrast agents

    DOEpatents

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

    1997-12-30

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

  4. Nuclear magnetic resonance contrast agents

    DOEpatents

    Smith, Paul H.; Brainard, James R.; Jarvinen, Gordon D.; Ryan, Robert R.

    1997-01-01

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

  5. New Method for Double-Resonance Spectroscopy in a Cold Quadrupole Ion Trap and Its Application to UV-UV Hole-Burning Spectroscopy of Protonated Adenine Dimer.

    PubMed

    Kang, Hyuk; Féraud, Géraldine; Dedonder-Lardeux, Claude; Jouvet, Christophe

    2014-08-01

    A novel method for double-resonance spectroscopy in a cold quadrupole ion trap is presented, which utilizes dipolar resonant excitation of fragment ions in the quadrupole ion trap. Photofragments by a burn laser are removed by applying an auxiliary RF to the trap, and a probe laser detects the depletion of photofragments by the burn laser. By scanning the wavelength of the burn laser, conformation-specific UV spectrum of a cold ion is obtained. This simple and powerful method is applicable to any type of double-resonance spectroscopy in a cold quadrupole ion trap and was applied to UV-UV hole-burning spectroscopy of protonated adenine dimer. It was found that protonated adenine dimer has multiple conformers/tautomers, each with multiple excited states with drastically different excited state dynamics.

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

    ERIC Educational Resources Information Center

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

    2000-01-01

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

  7. CP-violating effect of the Th nuclear magnetic quadrupole moment: accurate many-body study of ThO.

    PubMed

    Skripnikov, L V; Petrov, A N; Titov, A V; Flambaum, V V

    2014-12-31

    Investigations of CP violation in the hadron sector may be done using measurements in the ThO molecule. Recent measurements in this molecule improved the limit on the electron electric dipole moment (EDM) by an order of magnitude. Another time-reversal (T) and parity (P)-violating effect in 229ThO is induced by the nuclear magnetic quadrupole moment. We perform nuclear and molecular calculations to express this effect in terms of the strength constants of T, P-odd nuclear forces, neutron EDM, QCD vacuum angle θ, quark EDM, and chromo-EDM.

  8. 17O nuclear quadrupole coupling constants of water bound to a metal ion: A gadolinium(III) case study

    NASA Astrophysics Data System (ADS)

    Yazyev, Oleg V.; Helm, Lothar

    2006-08-01

    Rotational correlation times of metal ion aqua complexes can be determined from O17 NMR relaxation rates if the quadrupole coupling constant of the bound water oxygen-17 nucleus is known. The rotational correlation time is an important parameter for the efficiency of Gd3+ complexes as magnetic resonance imaging contrast agents. Using a combination of density functional theory with classical and Car-Parrinello molecular dynamics simulations we performed a computational study of the O17 quadrupole coupling constants in model aqua ions and the [Gd(DOTA)(H2O)]- complex used in clinical diagnostics. For the inner sphere water molecule in the [Gd(DOTA)(H2O)]- complex the determined quadrupole coupling parameter χ√1+η2/3 of 8.7MHz is very similar to that of the liquid water (9.0MHz ). Very close values were also predicted for the the homoleptic aqua ions of Gd3+ and Ca2+. We conclude that the O17 quadrupole coupling parameters of water molecules coordinated to closed shell and lanthanide metal ions are similar to water molecules in the liquid state.

  9. Nuclear magnetic resonance in Kondo lattice systems.

    PubMed

    Curro, Nicholas J

    2016-06-01

    Nuclear magnetic resonance has emerged as a vital tool to explore the fundamental physics of Kondo lattice systems. Because nuclear spins experience two different hyperfine couplings to the itinerant conduction electrons and to the local f moments, the Knight shift can probe multiple types of spin correlations that are not accessible via other techniques. The Knight shift provides direct information about the onset of heavy electron coherence and the emergence of the heavy electron fluid.

  10. Uniaxial compressive stress induced nuclear quadrupole interaction at the 111Cd nucleus in n-doped silicon

    NASA Astrophysics Data System (ADS)

    Tessema, Genene

    2006-03-01

    Stress induced quadrupole interaction at the probe nucleus ( 111Cd) in silicon has been studied using the perturbed γ-γ angular correlation (PAC) method. The extra nuclear field, at the sites of the nuclei, is produced via the disturbances of the surrounding charges by the action of a uniaxial compressive stress on the samples. However, the probes situated at various lattice locations in the sample showed different responses for the same value of stress. The various lattice environments are mainly caused by the involvement of either tellurium or antimony donor atoms in the samples. As a result, the donor free substitutional probe atoms experience a finite nuclear quadrupole interaction due to the broken symmetry of the charge distribution upon uniaxial compression; those probe atoms, which form pairs with donors, exhibit a strong electric-field gradient (EFG) that appears to be pressure independent.

  11. Nuclear Magnetic Resonance Technology for Medical Studies.

    ERIC Educational Resources Information Center

    Budinger, Thomas F.; Lauterbur, Paul C.

    1984-01-01

    Reports on the status of nuclear magnetic resonance (NMR) from theoretical and clinical perspectives, reviewing NMR theory and relaxation parameters relevant to NMR imaging. Also reviews literature related to modern imaging strategies, signal-to-noise ratio, contrast agents, in vivo spectroscopy, spectroscopic imaging, clinical applications, and…

  12. Sample spinner for nuclear magnetic resonance spectrometer

    SciTech Connect

    Stejskal, E.O.

    1984-05-01

    A sample spinner for a nuclear magnetic resonance spectrometer having improved operating characteristics is described comprising a rotor supported at both ends by support gas bearings and positioned by a thrust gas bearing. Improved support gas bearings are also described which result in a spinner exhibiting long-term stable operation characteristics.

  13. A theoretical study of 17O, 14N and 2H nuclear quadrupole coupling tensors in the real crystalline structure of acetaminophen

    NASA Astrophysics Data System (ADS)

    Behzadi, Hadi; Esrafili, Mehdi D.; Hadipour, Nasser L.

    2007-03-01

    A systematic computational investigation was carried out to characterize the 17O, 14N and 2H electric field gradient, EFG, tensors in the acetaminophen real crystalline structure. To include the hydrogen bonding effects in the calculations, the most probable interacting molecules with the target molecule in the crystalline phase were considered through the various molecular clusters. The calculations were performed with the B3LYP method and 6-311++G ∗∗ and 6-311+G ∗ standard basis sets using the Gaussian 98 suite of programs. Calculated EFG tensors were used to evaluate the 17O, 14N, and 2H nuclear quadrupole resonance, NQR, parameters in acetaminophen crystalline structure, which are in good agreement with the available experimental data. The difference between the calculated NQR parameters of the monomer and molecular clusters shows how much hydrogen bonding interactions affect the EFG tensors of each nucleus. These results indicate that both O-H⋯O and N-H⋯O hydrogen bonding have major influence on the NQR parameters. Moreover, the quantum chemical calculation indicated that the intermolecular hydrogen bonding interactions play an essential role in determining the relative orientation of quadrupole coupling principal components in the molecular frame axes.

  14. 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.

  15. Nuclear Resonance Fluorescence of 237 Np

    SciTech Connect

    Angell, Chris T.; Yee, R.; Joshi, T.; Swanberg, E.; Norman, E. B.; Hicks, C. L.; Klimenko, A.; Korbly, Steve; Wilson, C.; Kulp, W. D.; Warren, Glen A.; Bray, T. H.; Copping, R.; Glans, P.A.; Tyliszczak, T.; Shuh, David K.

    2010-11-15

    Identification and characterization of fissile material is of international concern because of the possibility of proliferation. For safeguards applications, techniques providing isotopic information are necessary [1]. However, few techniques can distinguish between fissile isotopes. Nuclear resonance fluorescence is one technique that can be used in applications to identify and quantify isotopic content. NRF has also been proposed in several detector systems as a viable way to identify fissile material in cargo containers [2, 3]. It is necessary to measure the characteristic resonances of each isotope that is to be distinguished in identification and assay applications.

  16. Nuclear resonance fluorescence of Np237

    NASA Astrophysics Data System (ADS)

    Angell, C. T.; Yee, R.; Joshi, T. H.; Swanberg, E.; Norman, E. B.; Hicks, C. L., Jr.; Klimenko, A.; Korbly, S.; Wilson, C.; Kulp, W. D.; Warren, G. A.; Bray, T. H.; Copping, R.; Glans, P. A.; Tyliszczak, T.; Shuh, D. K.

    2010-11-01

    Measurements of states excited by nuclear resonance fluorescence in Np237 were performed using a bremsstrahlung beam. Fifteen new states were observed in the region of 1.7 to 2.5 MeV. They can be used to detect or assay Np237 nondestructively for applications in security and safeguards. The states are populated with similar strength as those states found previously in U235 and Pu239 but are spread out more in energy.

  17. Nuclear resonance fluorescence of {sup 237}Np

    SciTech Connect

    Angell, C. T.; Yee, R.; Joshi, T. H.; Swanberg, E.; Norman, E. B.; Hicks, C. L. Jr.; Klimenko, A.; Korbly, S.; Wilson, C.; Kulp, W. D.; Warren, G. A.; Bray, T. H.; Copping, R.; Glans, P. A.; Tyliszczak, T.; Shuh, D. K.

    2010-11-15

    Measurements of states excited by nuclear resonance fluorescence in {sup 237}Np were performed using a bremsstrahlung beam. Fifteen new states were observed in the region of 1.7 to 2.5 MeV. They can be used to detect or assay {sup 237}Np nondestructively for applications in security and safeguards. The states are populated with similar strength as those states found previously in {sup 235}U and {sup 239}Pu but are spread out more in energy.

  18. Nuclear magnetic resonance quantum information processing

    PubMed Central

    Serra, R. M.; Oliveira, I. S.

    2012-01-01

    For the past decade, nuclear magnetic resonance (NMR) has been established as a main experimental technique for testing quantum protocols in small systems. This Theme Issue presents recent advances and major challenges of NMR quantum information possessing (QIP), including contributions by researchers from 10 different countries. In this introduction, after a short comment on NMR-QIP basics, we briefly anticipate the contents of this issue. PMID:22946031

  19. Nuclear Resonance Fluorescence for Materials Assay

    SciTech Connect

    Quiter, Brian; Ludewigt, Bernhard; Mozin, Vladimir; Prussin, Stanley

    2009-06-05

    This paper discusses the use of nuclear resonance fluorescence (NRF) techniques for the isotopic and quantitative assaying of radioactive material. Potential applications include age-dating of an unknown radioactive source, pre- and post-detonation nuclear forensics, and safeguards for nuclear fuel cycles Examples of age-dating a strong radioactive source and assaying a spent fuel pin are discussed. The modeling work has ben performed with the Monte Carlo radiation transport computer code MCNPX, and the capability to simulate NRF has bee added to the code. Discussed are the limitations in MCNPX's photon transport physics for accurately describing photon scattering processes that are important contributions to the background and impact the applicability of the NRF assay technique.

  20. Nuclear Resonance Fluorescence for Materials Assay

    SciTech Connect

    Quiter, Brian J.; Ludewigt, Bernhard; Mozin, Vladimir; Prussin, Stanley

    2009-06-29

    This paper discusses the use of nuclear resonance fluorescence (NRF) techniques for the isotopic and quantitative assaying of radioactive material. Potential applications include age-dating of an unknown radioactive source, pre- and post-detonation nuclear forensics, and safeguards for nuclear fuel cycles Examples of age-dating a strong radioactive source and assaying a spent fuel pin are discussed. The modeling work has ben performed with the Monte Carlo radiation transport computer code MCNPX, and the capability to simulate NRF has bee added to the code. Discussed are the limitations in MCNPX?s photon transport physics for accurately describing photon scattering processes that are important contributions to the background and impact the applicability of the NRF assay technique.

  1. Nuclear magnetic resonance properties of lunar samples.

    NASA Technical Reports Server (NTRS)

    Kline, D.; Weeks, R. A.

    1972-01-01

    Nuclear magnetic resonance spectra of Na-23, Al-27, and P-31 in fines samples 10084,60 and 14163,168 and in crystalline rock samples 12021,55 and 14321,166, have been recorded over a range of frequencies up to 20 MHz. A shift in the field at which maximum absorption occurs for all of the spectra relative to the field at which maximum absorption occurs for terrestrial analogues is attributed to a sample-dependent magnetic field at the Na, Al, and P sites opposing the laboratory field. The magnitude of these fields internal to the samples is sample dependent and varies from 5 to 10 G. These fields do not correlate with the iron content of the samples. However, the presence of single-domain particles of iron distributed throughout the plagioclase fraction that contains the principal fraction of Na and Al is inferred from electron magnetic resonance spectra shapes.

  2. Iodine: Many Electrons and much to DISCUSS...THE Nuclear Quadrupole Coupling, Nuclear Spin-Rotation Conformational Analysis, and Structural Determination of 2-IODOBUTANE

    NASA Astrophysics Data System (ADS)

    Arsenault, Eric A.; Choi, Yoon Jeong; Obenchain, Daniel A.; Cooke, S. A.; Blake, Thomas A.; Novick, Stewart E.

    2016-06-01

    The rotational spectrum of 2-iodobutane (sec-butyl-iodide) has been collected from 5.5-16.5 GHz using jet-pulsed Fourier transform microwave spectroscopy on both broadband and Balle-Flygare cavity instruments. Transitions belonging to three unique conformers were observed, namley the gauche-, anti-, and gauche'- species. All four 13C isotopologues of the gauche-2-iodobutane were observed. The complete nuclear quadrupole coupling tensor of iodine has been determined for all conformers and 13C isotopologues. A comparison between these nuclear quadrupole coupling tensors and those of similar iodine-containing molecules will be presented. Changes in the quadrupole coupling of iodine upon isotopic substitution will also be discussed. Additionally, isotopic substitution in conjunction with ab initio calculations allowed for both an r_s and r_0 structural analysis of gauche-2-iodobutane. Brown, G. G.; Dian, B. C.; Douglass, K. O.; Geyer, S. M.; Shipman, S. T.; Pate, B. H. Review of Scientific Instruments 2008, 79, 053103. Balle, T.; Flygare, W. Review of Scientific Instruments 1981, 52, 33-45.

  3. The effects of proton-beam quality on the production of gamma rays for nuclear resonance absorption in nitrogen

    SciTech Connect

    Graybill, R.; Morgado, R.E.; Cappiello, C.C.

    1994-05-01

    The authors describe a method for performing nuclear-resonance absorption with the proton beam from a radio-frequency quadrupole (RFQ) linear accelerator. The objective was to assess the suitability of the pulsed beam from an RFQ to image nitrogen compared to electrostatic accelerators. This choice of accelerator results in trade-offs in performance and complexity, in return for the prospect of higher average current. In spite of a reduced resonance attenuation coefficient in nitrogen, they successfully produced three-dimensional tomographic images of real explosives in luggage the first time the unoptimized system was operated. The results and assessments of the initial laboratory measurements are reported.

  4. Reappraisal of nuclear quadrupole moments of atomic halogens via relativistic coupled cluster linear response theory for the ionization process.

    PubMed

    Chaudhuri, Rajat K; Chattopadhyay, Sudip; Mahapatra, Uttam Sinha

    2013-11-27

    The coupled cluster based linear response theory (CCLRT) with four-component relativistic spinors is employed to compute the electric field gradients (EFG) of (35)Cl, (79)Br, and (127)I nuclei. The EFGs resulting from these calculations are combined with experimental nuclear quadrupole coupling constants (NQCC) to determine the nuclear quadrupole moments (NQM), Q of the halide nuclei. Our estimated NQMs [(35)Cl = -81.12 mb, (79)Br = 307.98 mb, and (127)I = -688.22 mb] agree well with the new atomic values [(35)Cl = -81.1(1.2), (79)Br = 302(5), and (127)I = -680(10) mb] obtained via Fock space multireference coupled cluster method with the Dirac-Coulomb-Breit Hamiltonian. Although our estimated Q((79)Br) value deviates from the accepted reference value of 313(3) mb, it agrees well with the recently recommended value, Q((79)Br) = 308.7(20) mb. Good agreement with current reference data indicates the accuracy of the proposed value for these halogen nuclei and lends credence to the results obtained via CCLRT approach. The electron affinities yielded by this method with no extra cost are also in good agreement with experimental values, which bolster our belief that the NQMs values for halogen nuclei derived here are reliable.

  5. An introduction to nuclear magnetic resonance in biomedicine.

    PubMed

    Andrew, E R

    1990-02-01

    In this paper the author illustrates the historical aspects of the development, first, of the fundamental principles of nuclear magnetic resonance and, second, the extension of these principles to magnetic resonance imaging and in vivo spectroscopy.

  6. Nuclear charge radii and electric quadrupole moments of even-even isotopes

    SciTech Connect

    Nerlo-Pomorska, B.; Mach, B.

    1995-07-01

    Isotope shifts of the charge mean-square radii and electric quadrupole moments of even-even nuclei with 20{le}{Zeta}{le}98 are calculated using a dynamical microscopic model. A single-particle Nilsson potential with the Seo set of correction terms, pairing forces in the BCS formalism, and a long-range interaction in the local approximation are used. A collective Hamiltionian is obtained using a generator coordinate method with the Gaussian overlap approximation. The potential energy of the nucleus consists of a microscopic-macroscopic Strutinsky energy and a zero-point vibrational term. A liquid droplet model is used for the macroscopic part of the potential. A BCS wave function is taken as a generator function, and two collective variables, quadrupole and hexadecapole deformations, serve as the generator coordinates. In general, good agreement between the theory and experimental data is achieved. 16 refs., 8 figs., 1 tab.

  7. Cavity- and waveguide-resonators in electron paramagnetic resonance, nuclear magnetic resonance, and magnetic resonance imaging.

    PubMed

    Webb, Andrew

    2014-11-01

    Cavity resonators are widely used in electron paramagnetic resonance, very high field magnetic resonance microimaging and also in high field human imaging. The basic principles and designs of different forms of cavity resonators including rectangular, cylindrical, re-entrant, cavity magnetrons, toroidal cavities and dielectric resonators are reviewed. Applications in EPR and MRI are summarized, and finally the topic of traveling wave MRI using the magnet bore as a waveguide is discussed.

  8. Characterization of nuclear material by Neutron Resonance Transmission Analysis

    NASA Astrophysics Data System (ADS)

    Paradela, C.; Alaerts, G.; Becker, B.; Heyse, J.; Kopecky, S.; Moens, A.; Mondelaers, W.; Schillebeeckx, P.; Wynants, R.; Harada, H.; Kitatani, F.; Koizumi, M.; Tsuchiya, H.

    2016-11-01

    The use of Neutron Resonance Transmission Analysis for the characterization of nuclear materials is discussed. The method, which relies on resonance structures in neutron-induced reaction cross sections, can be applied as a non-destructive method to characterise complex nuclear materials such as melted fuel resulting from a severe nuclear accident. Results of a demonstration experiment at the GELINA facility reveal that accurate data can be obtained at a compact facility even in the case of strong overlapping resonances.

  9. Oxygen depth profiling by nuclear resonant scattering

    SciTech Connect

    Gibson, G. T.; Sheu, W. J.; Glass, G. A.; Wang, Y. Q.

    1999-06-10

    Nuclear resonance scattering (NRS) {sup 16}O({alpha},{alpha}){sup 16}O at 3.045 MeV ({gamma}=10 keV) has been used for oxygen depth profiling in various thin oxide films. There are two ways by which the oxygen concentration versus depth profile can be obtained from the experimental data: energy spectrum simulation or yield distribution analysis. Energy spectrum simulation is done using the standard RBS software/Rutherford Universal Manipulation Program (RUMP) where only one spectrum is usually needed from the measurement. Yield distribution analysis is accomplished by using a custom developed software/Resonance Analysis Program (RAP) and involves a series of spectra obtained by stepping up the beam energy above the resonance energy. This article aims at comparing the fundamentals of both methods and also discussing their advantages and disadvantages in terms of the data acquisition and the post data analysis. A thermally grown thick SiO{sub 2} film and a thin titanium oxide film grown by corona point discharge were examined.

  10. Oxygen depth profiling by nuclear resonant scattering

    SciTech Connect

    Gibson, G.T.; Sheu, W.J.; Glass, G.A. Wang, Y.Q.

    1999-06-01

    Nuclear resonance scattering (NRS) {sup 16}O({alpha},{alpha}){sup 16}O at 3.045 MeV ({Gamma}=10&hthinsp;keV) has been used for oxygen depth profiling in various thin oxide films. There are two ways by which the oxygen concentration versus depth profile can be obtained from the experimental data: energy spectrum simulation or yield distribution analysis. Energy spectrum simulation is done using the standard RBS software/Rutherford Universal Manipulation Program (RUMP) where only one spectrum is usually needed from the measurement. Yield distribution analysis is accomplished by using a custom developed software/Resonance Analysis Program (RAP) and involves a series of spectra obtained by stepping up the beam energy above the resonance energy. This article aims at comparing the fundamentals of both methods and also discussing their advantages and disadvantages in terms of the data acquisition and the post data analysis. A thermally grown thick SiO{sub 2} film and a thin titanium oxide film grown by corona point discharge were examined. {copyright} {ital 1999 American Institute of Physics.}

  11. Assessment of Nuclear Resonance Fluorescence for Spent Nuclear Fuel Assay

    SciTech Connect

    Quiter, Brian; Ludewigt, Bernhard; Ambers, Scott

    2011-06-30

    In nuclear resonance fluorescence (NRF) measurements, resonances are excited by an external photon beam leading to the emission of gamma rays with specific energies that are characteristic of the emitting isotope. NRF promises the unique capability of directly quantifying a specific isotope without the need for unfolding the combined responses of several fissile isotopes as is required in other measurement techniques. We have analyzed the potential of NRF as a non-destructive analysis technique for quantitative measurements of Pu isotopes in spent nuclear fuel (SNF). Given the low concentrations of 239Pu in SNF and its small integrated NRF cross sections, the main challenge in achieving precise and accurate measurements lies in accruing sufficient counting statistics in a reasonable measurement time. Using analytical modeling, and simulations with the radiation transport code MCNPX that has been experimentally tested recently, the backscatter and transmission methods were quantitatively studied for differing photon sources and radiation detector types. Resonant photon count rates and measurement times were estimated for a range of photon source and detection parameters, which were used to determine photon source and gamma-ray detector requirements. The results indicate that systems based on a bremsstrahlung source and present detector technology are not practical for high-precision measurements of 239Pu in SNF. Measurements that achieve the desired uncertainties within hour-long measurements will either require stronger resonances, which may be expressed by other Pu isotopes, or require quasi-monoenergetic photon sources with intensities that are approximately two orders of magnitude higher than those currently being designed or proposed.This work is part of a larger effort sponsored by the Next Generation Safeguards Initiative to develop an integrated instrument, comprised of individual NDA techniques with complementary features, that is fully capable of

  12. Nuclear Resonance Fluorescence of ^148Sm

    NASA Astrophysics Data System (ADS)

    Li, T. C.; Pietralla, N.; von Garrel, H.; Kneissl, U.; Kohstall, C.; Pitz, H. H.; Scheck, M.; Stedile, F.; von Neumann-Cosel, P.; Richter, A.; Fransen, C.; Werner, V.

    2004-10-01

    The evolution of the fundamental one-phonon 2^+_1,ms proton-neutron mixed-symmetry state as a function of nuclear deformation is unknown. The sequence of stable Sm isotopes represents the classic testing ground for the evolution of nuclear structure with quadruple deformation. In order to search for the 2^+_1,ms state of ^148Sm, we have studied the ^148Sm (γ,γ') photon scattering reaction at the Stuttgart DYNAMITRON accelerator using bremsstrahlung with an end point energy of 3.2 MeV. Nuclear resonance fluorescence from 11 excited states, including two 2^+ states, between 1.4 and 3.1 MeV has been observed with 3 large-volume Ge detectors. New low-spin states were observed. Spin quantum numbers were assigned from the angular distribution of the photon scattering intensity observed at θ = 90^o, 127^o and 150^o relative to the axis of the incident photon beam. Absolute photon scattering cross sections were measured relative to known cross sections in the calibration standard ^27Al. Level lifetimes have been deduced. The results will be presented. Supported by the NSF under grant No. PHY-0245018 and by the OJI program of the DOE under grant No. DE-FG02-04ER41334.

  13. Nuclear magnetic resonance imaging of liver hemangiomas

    SciTech Connect

    Sigal, R.; Lanir, A.; Atlan, H.; Naschitz, J.E.; Simon, J.S.; Enat, R.; Front, D.; Israel, O.; Chisin, R.; Krausz, Y.

    1985-10-01

    Nine patients with cavernous hemangioma of the liver were examined by nuclear magnetic resonance imaging (MRI) with a 0.5 T superconductive magnet. Spin-echo technique was used with varying time to echo (TE) and repetition times (TR). Results were compared with /sup 99m/Tc red blood cell (RBC) scintigraphy, computed tomography (CT), echography, and arteriography. Four illustrated cases are reported. It was possible to establish a pattern for MRI characteristics of cavernous hemangiomas; rounded or smooth lobulated shape, marked increase in T1 and T2 values as compared with normal liver values. It is concluded that, although more experience is necessary to compare the specificity with that of ultrasound and CT, MRI proved to be very sensitive for the diagnosis of liver hemangioma, especially in the case of small ones which may be missed by /sup 99m/Tc-labeled RBC scintigraphy.

  14. Near-Zero-Field Nuclear Magnetic Resonance

    NASA Astrophysics Data System (ADS)

    Ledbetter, M. P.; Theis, T.; Blanchard, J. W.; Ring, H.; Ganssle, P.; Appelt, S.; Blümich, B.; Pines, A.; Budker, D.

    2011-09-01

    We investigate nuclear magnetic resonance (NMR) in near zero field, where the Zeeman interaction can be treated as a perturbation to the electron mediated scalar interaction (J coupling). This is in stark contrast to the high-field case, where heteronuclear J couplings are normally treated as a small perturbation. We show that the presence of very small magnetic fields results in splitting of the zero-field NMR lines, imparting considerable additional information to the pure zero-field spectra. Experimental results are in good agreement with first-order perturbation theory and with full numerical simulation when perturbation theory breaks down. We present simple rules for understanding the splitting patterns in near-zero-field NMR, which can be applied to molecules with nontrivial spectra.

  15. Geochemical Controls on Nuclear Magnetic Resonance Measurements

    SciTech Connect

    Knight, Rosemary; Prasad, Manika; Keating, Kristina

    2003-11-11

    OAK-B135 Our research objectives are to determine, through an extensive set of laboratory experiments, the effect of the specific mineralogic form of iron and the effect of the distribution of iron on proton nuclear magnetic resonance (NMR) relaxation mechanisms. In the first nine months of this project, we have refined the experimental procedures to be used in the acquisition of the laboratory NMR data; have ordered, and conducted preliminary measurements on, the sand samples to be used in the experimental work; and have revised and completed the theoretical model to use in this project. Over the next year, our focus will be on completing the first phase of the experimental work where the form and distribution of the iron in the sands in varied.

  16. Two-dimensional nuclear magnetic resonance petrophysics.

    PubMed

    Sun, Boqin; Dunn, Keh-Jim

    2005-02-01

    Two-dimensional nuclear magnetic resonance (2D NMR) opens a wide area for exploration in petrophysics and has significant impact to petroleum logging technology. When there are multiple fluids with different diffusion coefficients saturated in a porous medium, this information can be extracted and clearly delineated from CPMG measurements of such a system either using regular pulsing sequences or modified two window sequences. The 2D NMR plot with independent variables of T2 relaxation time and diffusion coefficient allows clear separation of oil and water signals in the rocks. This 2D concept can be extended to general studies of fluid-saturated porous media involving other combinations of two or more independent variables, such as chemical shift and T1/T2 relaxation time (reflecting pore size), proton population and diffusion contrast, etc. PMID:15833623

  17. In vivo nuclear magnetic resonance imaging

    NASA Technical Reports Server (NTRS)

    Leblanc, A.; Evans, H.; Bryan, R. N.; Johnson, P.; Schonfeld, E.; Jhingran, S. G.

    1984-01-01

    A number of physiological changes have been demonstrated in bone, muscle and blood after exposure of humans and animals to microgravity. Determining mechanisms and the development of effective countermeasures for long duration space missions is an important NASA goal. The advent of tomographic nuclear magnetic resonance imaging (NMR or MRI) gives NASA a way to greatly extend early studies of this phenomena in ways not previously possible; NMR is also noninvasive and safe. NMR provides both superb anatomical images for volume assessments of individual organs and quantification of chemical/physical changes induced in the examined tissues. The feasibility of NMR as a tool for human physiological research as it is affected by microgravity is demonstrated. The animal studies employed the rear limb suspended rat as a model of mucle atrophy that results from microgravity. And bedrest of normal male subjects was used to simulate the effects of microgravity on bone and muscle.

  18. Nuclear Resonance Fluorescence Using Different Photon Sources

    SciTech Connect

    Warren, Glen A.; Caggiano, Joseph A.; Ahmed, Mohammad; Bertozzi, William; Hunt, Alan W.; Johnson, James; Jones, James L.; Korbly, Steve; Reedy, Edward; Seipel, Heather; Stave, Sean; Watson, Scott; Weller, Henry

    2008-11-14

    Abstract–Nuclear resonance fluorescence (NRF) is a photon-based active interrogation approach that provides isotope-specific signatures that can be used to detect and characterize samples. As NRF systems are designed to address specific appli¬cations, an obvious first question to address is the type of photon source to be employed for the application. Our collaboration has conducted a series of NRF measurements using different photon sources to begin to examine this issue. The measurements were designed to be as similar as possible to facilitate a straightforward comparison of the different sources. Measurements were conducted with a high-duty factor electron accelerator using bremsstrahlung photons, with a pulsed linear accelerator using bremsstrahlung photons, and with a narrow bandwidth photon source using Compton backscattered photons. We present our observations on the advantages and disadvantages of each photon source type. Issues such as signal rate, the signal-to-noise ratio, and absorbed dose are discussed.

  19. Musculoskeletal applications of nuclear magnetic resonance

    SciTech Connect

    Moon, K.L. Jr.; Genant, H.K.; Helms, C.A.; Chafetz, N.I.; Crooks, L.E.; Kaufman, L.

    1983-04-01

    Thirty healthy subjects and 15 patients with a variety of musculoskeletal disorders were examined by conventional radiography, computed tomography (CT), and nuclear magnetic resonance (NMR). NMR proved capable of demonstrating important anatomic structures in the region of the lumbosacral spine. Lumbar disk protrusion was demonstrated in three patients with CT evidence of the disease. NMR appeared to differentiate annulus fibrosus from nucleus pulposus in intervertebral disk material. Avascular necrosis of the femoral head was demonstrated in two patients. The cruciate ligaments of the knee were well defined by NMR. Musceles, tendons and ligaments, and blood vessels could be reliably differentiated, and the excellent soft-tissue contrast of NMR proved useful in the evaluation of bony and soft-tissue tumors. NMR holds promise in the evaluation of musculoskeletal disorders.

  20. Electron transfer dissociation in the hexapole collision cell of a hybrid quadrupole-hexapole Fourier transform ion cyclotron resonance mass spectrometer.

    PubMed

    Kaplan, Desmond A; Hartmer, Ralf; Speir, J Paul; Stoermer, Carsten; Gumerov, Dmitry; Easterling, Michael L; Brekenfeld, Andreas; Kim, Taeman; Laukien, Frank; Park, Melvin A

    2008-01-01

    Electron transfer dissociation (ETD) of proteins is demonstrated in a hybrid quadrupole-hexapole Fourier transform ion cyclotron resonance mass spectrometer (Qh-FTICRMS). Analyte ions are selected in the mass analyzing quadrupole, accumulated in the hexapole linear ion trap, reacted with fluoranthene reagent anions, and then analyzed via an FTICR mass analyzer. The hexapole trap allows for a broad fragment ion mass range and a high ion storage capacity. Using a 3 T FTICRMS, resolutions of 60 000 were achieved with mass accuracies averaging below 1.4 ppm. The high resolution, high mass accuracy ETD spectra provided by FTICR obviates the need for proton transfer reaction (PTR) charge state reduction of ETD product ions when analyzing proteins or large peptides. This is demonstrated with the ETD of ubiquitin and apomyoglobin yielding sequence coverages of 37 and 20%, respectively. We believe this represents the first reported successful combination of ETD and a FTICRMS.

  1. A new technique for unbiased external ion accumulation in a quadrupole two-dimensional ion trap for electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry.

    PubMed

    Belov, M E; Nikolaev, E N; Alving, K; Smith, R D

    2001-01-01

    External ion accumulation in a two-dimensional (2D) multipole trap has been shown to increase the sensitivity, dynamic range and duty cycle of a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer. However, it is important that trapped ions be detected without significant bias at longer accumulation times in the external 2D multipole trap. With increasing ion accumulation time pronounced m/z discrimination was observed when trapping ions in an accumulation quadrupole. In this work we show that superimposing lower rf-amplitude dipolar excitation over the main rf-field in the accumulation quadrupole results in disruption of the m/z discrimination and can potentially be used to achieve unbiased external ion accumulation with FTICR.

  2. Selectivity in multiple quantum nuclear magnetic resonance

    SciTech Connect

    Warren, W.S.

    1980-11-01

    The observation of multiple-quantum nuclear magnetic resonance transitions in isotropic or anisotropic liquids is shown to give readily interpretable information on molecular configurations, rates of motional processes, and intramolecular interactions. However, the observed intensity of high multiple-quantum transitions falls off dramatically as the number of coupled spins increases. The theory of multiple-quantum NMR is developed through the density matrix formalism, and exact intensities are derived for several cases (isotropic first-order systems and anisotropic systems with high symmetry) to shown that this intensity decrease is expected if standard multiple-quantum pulse sequences are used. New pulse sequences are developed which excite coherences and produce population inversions only between selected states, even though other transitions are simultaneously resonant. One type of selective excitation presented only allows molecules to absorb and emit photons in groups of n. Coherent averaging theory is extended to describe these selective sequences, and to design sequences which are selective to arbitrarily high order in the Magnus expansion. This theory and computer calculations both show that extremely good selectivity and large signal enhancements are possible.

  3. Nuclear Resonance Fluorescence for Safeguards Applications

    SciTech Connect

    Ludewigt, Bernhard A; Quiter, Brian J; Ambers, Scott D

    2011-02-04

    In nuclear resonance fluorescence (NRF) measurements, resonances are excited by an external photon beam leading to the emission of {gamma} rays with specific energies that are characteristic of the emitting isotope. The promise of NRF as a non-destructive analysis technique (NDA) in safeguards applications lies in its potential to directly quantify a specific isotope in an assay target without the need for unfolding the combined responses of several fissile isotopes as often required by other NDA methods. The use of NRF for detection of sensitive nuclear materials and other contraband has been researched in the past. In the safeguards applications considered here one has to go beyond mere detection and precisely quantify the isotopic content, a challenge that is discussed throughout this report. Basic NRF measurement methods, instrumentation, and the analytical calculation of NRF signal strengths are described in Section 2. Well understood modeling and simulation tools are needed for assessing the potential of NRF for safeguards and for designing measurement systems. All our simulations were performed with the radiation transport code MCNPX, a code that is widely used in the safeguards community. Our initial studies showed that MCNPX grossly underestimated the elastically scattered background at backwards angles due to an incorrect treatment of Rayleigh scattering. While new, corrected calculations based on ENDF form factors showed much better agreement with experimental data for the elastic scattering of photons on an uranium target, the elastic backscatter is still not rigorously treated. Photonuclear scattering processes (nuclear Thomson, Delbruck and Giant Dipole Resonance scattering), which are expected to play an important role at higher energies, are not yet included. These missing elastic scattering contributions were studied and their importance evaluated evaluated against data found in the literature as discussed in Section 3. A transmission experiment

  4. Phosphorus 31 nuclear magnetic resonance examination of female reproductive tissues

    SciTech Connect

    Noyszewski, E.A.; Raman, J.; Trupin, S.R.; McFarlin, B.L.; Dawson, M.J. )

    1989-08-01

    Nuclear magnetic resonance spectroscopy is a powerful method of investigating the relationship between metabolism and function in living tissues. We present evidence that the phosphorus 31 spectra of myometrium and placenta are functions of physiologic state and gestational age. Specific spectroscopic abnormalities are observed in association with disorders of pregnancy and gynecologic diseases. Our results suggest that noninvasive nuclear magnetic resonance spectroscopy examinations may sometimes be a useful addition to magnetic resonance imaging examinations, and that nuclear magnetic resonance spectroscopy of biopsy specimens could become a cost-effective method of evaluating certain biochemical abnormalities.

  5. Investigation of the Rotational Spectrum of Pyrimidine from 3 to 337 GHz: Molecular Structure, Nuclear Quadrupole Coupling, and Vibrational Satellites.

    PubMed

    Kisiel; Pszczólkowski; López; Alonso; Maris; Caminati

    1999-06-01

    A comprehensive reinvestigation of the rotational spectrum of pyrimidine was carried out by using several different spectrometers. All singly substituted 13C- and 15N-isotopic species of pyrimidine have been measured in natural abundance with millimeter-wave free jet and waveguide Fourier transform microwave techniques, and complete rs and r0 heavy atom geometries have been determined. The ground state rotational spectrum in the centimeter-wave region was measured at sub-Doppler resolution of the cavity Fourier transform spectrometer and all elements in the inertial and principal nuclear quadrupole-coupling tensors of the nitrogen nuclei in pyrimidine have been determined. The room-temperature spectrum was measured up to 337 GHz and J = 66 with BWO-based spectrometers and sextic level centrifugal distortion constants in the rotational Hamiltonian have been determined for the ground state and three lowest vibrational fundamentals of pyrimidine. Copyright 1999 Academic Press.

  6. The position of deuterium in HOD—NNO as determined by structural and nuclear quadrupole coupling constants

    SciTech Connect

    Obenchain, Daniel A.; Frank, Derek S.; Novick, Stewart E.; Klemperer, William

    2015-08-28

    Rotational spectra of the weakly bound H{sub 2}O—N{sub 2}O complex and its HOD—N{sub 2}O isotopologue in a supersonic jet are reported. Rotational constants of the singly substituted deuterium in water and each singly substituted nitrogen-15 are presented. Combinations of isotopic data and high level ab initio calculations place the water in a similar position to those of the isoelectronic H{sub 2}O—CO{sub 2} complex, with a slight tilt of the OH towards the NNO axis. The deuterium nuclear quadrupole coupling constant places the deuterium on the O—H axis quasi-parallel to the NNO axis.

  7. Effects of a realistic tensor force on nuclear quadrupole deformation near the "shore" of the island of inversion

    NASA Astrophysics Data System (ADS)

    Suzuki, Y.; Nakada, H.; Miyahara, S.

    2016-08-01

    The M3Y-type semirealistic interaction is applied to deformed nuclei for the first time. Constrained Hartree-Fock calculations assuming axial symmetry are implemented for the N =20 isotones 30Ne, 32Mg, 34Si and the N =28 isotones 40Mg, 42Si, 44S with the M3Y-P6 interaction. The results match the experimental data well. Effects of the realistic tensor force on the nuclear quadrupole deformation are investigated in relation to the loss of the N =20 and 28 magic numbers. The tensor force is confirmed to favor the deformation for the N =28 nuclei owing to the closure of the j j shell (i.e., n 0 f7 /2 ), while favoring the sphericity for the N =20 nuclei owing to the ℓ s closure of N =20 .

  8. Potential Applications of Nuclear Resonance Fluorescence

    NASA Astrophysics Data System (ADS)

    Warren, Glen; Caggiano, Jac; Peplowski, Patrick

    2009-12-01

    Nuclear resonance fluorescence (NRF) is a photon-based active interrogation approach that provides isotope-specific signatures that can be used to detect and characterize samples. Photon energies are in the range of a few MeV, so that penetration through significant material is possible. Unlike other active interrogation techniques that are based on inducing fission, NRF is sensitive to a wide range of isotopes: for example 11B, 12C, 13C, 14N, 16O, 27Al, 208Pb, 235U, 238U and 239Pu just to name a few. NRF is most likely to outperform existing technologies for applications requiring isotopic information of sealed samples. Pacific Northwest National Laboratory is conducting a review of potential applications that could be addressed by NRF techniques. These applications cover a wide range of topics, from geo-location, to material assay, to safeguarding the nuclear fuel cycle. The objective of the project is to search for potential applications, define technical requirements, identify physical limitations, conduct an initial assessment of the technique and design a research approach for developing the applications. In this report, our current progress on will be presented.

  9. Experiments in Nuclear Magnetic Resonance Microscopy

    NASA Astrophysics Data System (ADS)

    Lee, Yong; Lu, Wei; Choi, J.-H.; Chia, H. J.; Mirsaidov, U. M.; Guchhait, S.; Cambou, A. D.; Cardenas, R.; Park, K.; Markert, J. T.

    2006-03-01

    We report our group's effort in the construction of an 8-T, ^3 He cryostat based nuclear magnetic resonance force microscope (NMRFM). The probe has two independent 3-D of piezoelectric x-y-z positioners for precise positioning of a fiber optic interferometer and a sample/gradient-producing magnet with respect to a micro-cantilever. The piezoelectric positioners have a very uniform controllable step size with virtually no backlash. A novel RF tuning circuit board design is implemented which allows us to simply swap out one RF component board with another for experiments involving different nuclear species. We successfully fabricated and are characterizing 50μm x50μm x0.2μm double torsional oscillators. We have also been characterizing ultrasoft cantilevers whose spring constant is on the order of 10-4 N/m. We also report NMRFM data for ammonium dihydrogen phosphate(ADP) at room temperature using our 1.2-T system. Observed features include the correct shift of the NMR peak with carrier frequency, increases in signal amplitude with both RF field strength and frequency modulation amplitude, and signal oscillation (spin nutation) as a function of tipping RF pulse length. Experiments in progress on NH4MgF3 (at 1.2 T) and MgB2 (at 8.1 T) will also be briefly reviewed. Robert A. Welch Foundation grant No.F-1191 and the National Science Foundation grant No. DMR-0210383.

  10. BROADBAND EXCITATION IN NUCLEAR MAGNETIC RESONANCE

    SciTech Connect

    Tycko, R.

    1984-10-01

    Theoretical methods for designing sequences of radio frequency (rf) radiation pulses for broadband excitation of spin systems in nuclear magnetic resonance (NMR) are described. The sequences excite spins uniformly over large ranges of resonant frequencies arising from static magnetic field inhomogeneity, chemical shift differences, or spin couplings, or over large ranges of rf field amplitudes. Specific sequences for creating a population inversion or transverse magnetization are derived and demonstrated experimentally in liquid and solid state NMR. One approach to broadband excitation is based on principles of coherent averaging theory. A general formalism for deriving pulse sequences is given, along with computational methods for specific cases. This approach leads to sequences that produce strictly constant transformations of a spin system. The importance of this feature in NMR applications is discussed. A second approach to broadband excitation makes use of iterative schemes, i.e. sets of operations that are applied repetitively to a given initial pulse sequences, generating a series of increasingly complex sequences with increasingly desirable properties. A general mathematical framework for analyzing iterative schemes is developed. An iterative scheme is treated as a function that acts on a space of operators corresponding to the transformations produced by all possible pulse sequences. The fixed points of the function and the stability of the fixed points are shown to determine the essential behavior of the scheme. Iterative schemes for broadband population inversion are treated in detail. Algebraic and numerical methods for performing the mathematical analysis are presented. Two additional topics are treated. The first is the construction of sequences for uniform excitation of double-quantum coherence and for uniform polarization transfer over a range of spin couplings. Double-quantum excitation sequences are demonstrated in a liquid crystal system. The

  11. Burn injury by nuclear magnetic resonance imaging.

    PubMed

    Eising, Ernst G; Hughes, Justin; Nolte, Frank; Jentzen, Walter; Bockisch, Andreas

    2010-01-01

    Nuclear magnetic resonance imaging has become a standard diagnostic procedure in clinical medicine and is well known to have hazards for patients with pacemaker or metallic foreign bodies. Compared to CT, the frequency of MRI examinations is increasing due to the missing exposure of the patients by X-rays. Furthermore, high-field magnetic resonance tomograph (MRT) with 3 T has entered clinical practice, and 7-T systems are installed in multiple scientific institutions. On the other hand, the possibility of burn injuries has been reported only in very few cases. Based on a clinical finding of a burn injury in a 31-year-old male patient during a routine MRI of the lumbar spine with standard protocol, the MR scanner was checked and the examination was simulated in an animal model. The patient received a third-degree burn injury of the skin of the right hand and pelvis in a small region of skin contact. The subsequent control of the MRI scanner indicated no abnormal values for radiofrequency (RF) and power. In the subsequent animal experiment, comparable injuries could only be obtained by high RF power in a microwave stove. It is concluded that 'tissue loops' resulting from a contact between hand and pelvis must be avoided. With regard to forensic aspects, the need to inform patients of such a minimal risk can be avoided if the patients are adequately positioned using an isolating material between the hands and pelvis. These facts must be emphasized more in the future, if high-field MRI with stronger RF gradients is available in routine imaging. PMID:20630342

  12. 14N Quadrupole Resonance in the presence of a weak static magnetic field. Direct determination of the electric field gradient tensor

    NASA Astrophysics Data System (ADS)

    Aissani, Sarra; Guendouz, Laouès; Canet, Daniel

    2014-02-01

    The electric field gradient tensor (considered here at the level of a nitrogen nucleus) can be described by two parameters: the largest element in the (x, y, z) principal axis system, denoted by Vzz, and the asymmetry parameter η=(Vyy-Vxx)/Vzz. The frequencies of the three nitrogen-14 NQR transitions depend on both parameters and two of them are, a priori, necessary for their determination. We demonstrate that, if a weak static magnetic field is applied during a NQR experiment, both parameters can be obtained from a single transition thus alleviating the difficulties for finding out 14N Quadrupole Resonance lines.

  13. Nuclear quadrupole interaction studies of C15 RMn2 hydrides ( R=Y ,Gd,Tb,Dy)

    NASA Astrophysics Data System (ADS)

    Forker, M.; Bedi, S. C.; Euler, H.

    2008-09-01

    The nuclear electric quadrupole interaction (QI) of the probe nucleus I111n/C111d in the paramagnetic phase of the C15 rare earth (R) manganese hydrides (deuterides) RMn2H(D)x , with R=Y , Gd, Tb, and Dy, has been investigated by perturbed angular-correlation spectroscopy. The QI between the C111d quadrupole moment and the electric-field gradient (EFG) at the probe nucleus on the Mn site has been measured as a function of temperature in TbMn2H(D)x in the concentration range 0≤x≤4.3 and in RMn2H(D)x , R=Y ,Gd,Dy at the highest H content of xtilde 4.3 . The relative temperature dependence of the EFG in the parent compounds RMn2 is twice as strong as in isostructural RAl2 which can be related to differences in the Debye temperatures resulting from different radius ratios rR/rMn and rR/rAl [Joseph-Gschneidner postulate, Scr. Metall.2, 631 (1968)]. Hydrogenation of RMn2 increases the magnitude of the EFG by a factor of 2 between x=0 and x=4.3 but leaves the relative temperature dependence almost unchanged. Only at concentrations x>3.6 the temperature coefficient of the QI is significantly larger than in uncharged RMn2 . These results are compared with the much stronger concentration dependence and the anomalous temperature dependence of the QI of C111d in the C15 hydrides HfV2Hx . Evidence for an exceptionally high H mobility in TbMn2Hx is presented. The measurements provide information on structural changes and magnetic ordering temperatures at different H concentrations.

  14. Nuclear magnetic resonance imaging of the kidney

    SciTech Connect

    Hricak, H.; Crooks, L.; Sheldon, P.; Kaufman, L.

    1983-02-01

    The role of nuclear magnetic resonance (NMR) imaging of the kidney was analyzed in 18 persons (6 normal volunteers, 3 patients with pelvocaliectasis, 2 with peripelvic cysts, 1 with renal sinus lipomatosis, 3 with renal failure, 1 with glycogen storage disease, and 2 with polycystic kidney disease). Ultrasound and/or computed tomography (CT) studies were available for comparison in every case. In the normal kidney distinct anatomical structures were clearly differentiated by NMR. The best anatomical detail ws obtained with spin echo (SE) imaging, using a pulse sequence interval of 1,000 msec and an echo delay time of 28 msec. However, in the evaluation of normal and pathological conditions, all four intensity images (SE 500/28, SE 500/56, SE 1,000/28, and SE 1,000/56) have to be analyzed. No definite advantage was found in using SE imaging with a pulse sequence interval of 1,500 msec. Inversion recovery imaging enhanced the differences between the cortex and medulla, but it had a low signal-to-noise level and, therefore, a suboptimal overall resolution. The advantages of NMR compared with CT and ultrasound are discussed, and it is concluded that NMR imaging will prove to be a useful modality in the evaluation of renal disease.

  15. Dynamic nuclear polarization and nuclear magnetic resonance in the vicinity of edge states of a 2DES in GaAs quantum wells.

    PubMed

    Bowers, Clifford R; Caldwell, Joshua D; Gusev, Guennadi; Kovalev, Alexey E; Olshanetsky, Eugene; Reno, John L; Simmons, Jerry A; Vitkalov, Sergey A

    2006-02-01

    Nuclear magnetic resonance is detected via the in-plane conductivity of a two-dimensional electron system at unity Landau level filling factor in the regime of the quantum Hall effect in narrow and wide quantum wells. The NMR is spatially selective to nuclei with a coupling to electrons in the current carrying edge states at the perimeter of the 2DES. Interpretation of the electron-nuclear double resonance signals is facilitated by numerical simulations. A new RF swept method for conductivity-detected NMR is introduced which offers more efficient signal averaging. The method is applied to the study of electric quadrupole interactions, weakly allowed overtone transitions, and evaluation of the extent of electron wave function delocalization in the wide quantum well.

  16. FY08 Annual Report for Nuclear Resonance Fluorescence Imaging

    SciTech Connect

    Warren, Glen A.; Caggiano, Joseph A.

    2009-01-06

    FY08 annual report for project the "Nuclear Resonance Fluorescence Imaging" project. Reviews accomplishments of last 3 years, including U-235 signature search, comparison of different photon sources, and examination of NRF measurements using monochromatic photon source.

  17. Nuclear Magnetic Double Resonance Using Weak Perturbing RF Fields

    ERIC Educational Resources Information Center

    Reynolds, G. Fredric

    1977-01-01

    Describes a nuclear magnetic resonance experimental example of spin tickling; also discusses a direct approach for verifying the relative signs of coupling constants in three-spin cyclopropyl systems. (SL)

  18. Single-level resonance parameters fit nuclear cross-sections

    NASA Technical Reports Server (NTRS)

    Drawbaugh, D. W.; Gibson, G.; Miller, M.; Page, S. L.

    1970-01-01

    Least squares analyses of experimental differential cross-section data for the U-235 nucleus have yielded single level Breit-Wigner resonance parameters that fit, simultaneously, three nuclear cross sections of capture, fission, and total.

  19. Nuclear magnetic resonance data of C10H13ITe

    NASA Astrophysics Data System (ADS)

    Mikhova, B. M.

    This document is part of Part 6 `Organic Metalloid Compounds' of Subvolume D 'Chemical Shifts and Coupling Constants for Carbon-13' of Landolt-Börnstein III/35 'Nuclear Magnetic Resonance Data', Group III 'Condensed Matter'.

  20. Nuclear magnetic resonance data of C9H11ITe

    NASA Astrophysics Data System (ADS)

    Mikhova, B. M.

    This document is part of Part 6 `Organic Metalloid Compounds' of Subvolume D 'Chemical Shifts and Coupling Constants for Carbon-13' of Landolt-Börnstein III/35 'Nuclear Magnetic Resonance Data', Group III 'Condensed Matter'.

  1. Nuclear magnetic resonance for cultural heritage.

    PubMed

    Brai, Maria; Camaiti, Mara; Casieri, Cinzia; De Luca, Francesco; Fantazzini, Paola

    2007-05-01

    Nuclear magnetic resonance (NMR) portable devices are now being used for nondestructive in situ analysis of water content, pore space structure and protective treatment performance in porous media in the field of cultural heritage. It is a standard procedure to invert T(1) and T(2) relaxation data of fully water-saturated samples to get "pore size" distributions, but the use of T(2) requires great caution. It is well known that dephasing effects due to water molecule diffusion in a magnetic field gradient can affect transverse relaxation data, even if the smallest experimentally available half echo time tau is used in Carr-Purcell-Meiboom-Gill experiments. When a portable single-sided NMR apparatus is used, large field gradients due to the instrument, at the scale of the sample, are thought to be the dominant dephasing cause. In this paper, T(1) and T(2) (at different tau values) distributions were measured in natural (Lecce stone) and artificial (brick samples coming from the Greek-Roman Theatre of Taormina) porous media of interest for cultural heritage by a standard laboratory instrument and a portable device. While T(1) distributions do not show any appreciable effect from inhomogeneous fields, T(2) distributions can show strong effects, and a procedure is presented based on the dependence of 1/T(2) on tau to separate pore-scale gradient effects from sample-scale gradient effects. Unexpectedly, the gradient at the pore scale can be, in some cases, strong enough to make negligible the effects of gradients at the sample scale of the single-sided device.

  2. Acoustic resonance spectroscopy in nuclear safeguards

    SciTech Connect

    Olinger, C.T.; Lyon, M.J.; Stanbro, W.D.; Mullen, M.F.; Sinha, D.N.

    1993-08-01

    Objects resonate at specific frequencies when mechanically excited. The specific resonance frequencies are a function of shape, size, material of construction, and contents of the object. This paper discusses the use of acoustic resonance spectroscopy (ARS) to monitor containers and detect tampering. Evaluation of this technique is based on simulated storage simulations. Although these simulations show promise for this application of ARS, final evaluation will require actual field testing.

  3. High-Accuracy Calculation of cu Electric-Field Gradients: a Revision of the cu Nuclear Quadrupole Moment Value

    NASA Astrophysics Data System (ADS)

    Cheng, Lan; Matthews, Devin A.; Gauss, Jürgen; Stanton, John F.

    2015-06-01

    A revision of the value for the Cu nuclear quadrupole moment (NQM) is reported based on high-accuracy ab initio calculations on the Cu electric field gradients in the CuF and CuCl molecules. Electron-correlation effects have systematically been taken into account using a hierarchy of coupled-cluster methods including up to quadruple excitations. It is shown that the CCSD(T)_Λ method provides a more reliable treatment of triples corrections for Cu electric-field gradients than the ubiquitously applied CCSD(T) method, which is tentatively attributed to the importance of the wavefunction relaxation in the calculations of a core property. Augmenting large-basis-set CCSD(T)_Λ results with the remaining corrections obtained using additive schemes, including full triples contributions, quadruples contributions, zero-point vibrational corrections, spin-orbit corrections, as well as the correction from the Gaunt term, a new value of 209.7(50) mbarn for the Cu NQM has been obtained. The new value substantially reduces the uncertainty of this parameter in comparison to the standard value of 220(15) mbarn obtained from a previous muonic experiment.

  4. Contraband Detection with Nuclear Resonance Fluorescence: Feasibility and Impact

    SciTech Connect

    Pruet, J; Lange, D

    2007-01-03

    In this report they show that cargo interrogation systems developed to thwart trafficking of illicit nuclear materials could also be powerful tools in the larger fight against contraband smuggling. In particular, in addition to detecting special nuclear materials, cargo scanning systems that exploit nuclear resonance fluorescence to detect specific isotopes can be used to help find: chemical weapons; some drugs as well as some chemicals regulated under the controlled substances act; precious metals; materials regulated under export control laws; and commonly trafficked fluorocarbons.

  5. Nuclear magnetic resonance spectroscopy with single spin sensitivity.

    PubMed

    Müller, C; Kong, X; Cai, J-M; Melentijević, K; Stacey, A; Markham, M; Twitchen, D; Isoya, J; Pezzagna, S; Meijer, J; Du, J F; Plenio, M B; Naydenov, B; McGuinness, L P; Jelezko, F

    2014-08-22

    Nuclear magnetic resonance spectroscopy and magnetic resonance imaging at the ultimate sensitivity limit of single molecules or single nuclear spins requires fundamentally new detection strategies. The strong coupling regime, when interaction between sensor and sample spins dominates all other interactions, is one such strategy. In this regime, classically forbidden detection of completely unpolarized nuclei is allowed, going beyond statistical fluctuations in magnetization. Here we realize strong coupling between an atomic (nitrogen-vacancy) sensor and sample nuclei to perform nuclear magnetic resonance on four (29)Si spins. We exploit the field gradient created by the diamond atomic sensor, in concert with compressed sensing, to realize imaging protocols, enabling individual nuclei to be located with Angstrom precision. The achieved signal-to-noise ratio under ambient conditions allows single nuclear spin sensitivity to be achieved within seconds.

  6. 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

    2016-04-01

    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

  7. 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

    2016-04-01

    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.

  8. Locking electron spins into resonance by electron-nuclear feedback

    NASA Astrophysics Data System (ADS)

    Nowack, Katja

    2009-03-01

    All basic building blocks for spin-based quantum information processing using electron spins in GaAs quantum dots have recently been realized. Recent experiments have shown single-shot read-out of an individual spin [1], the implementation of the SWAP gate [2] and (magnetically induced) coherent single electron spin rotations [3]. However, the main drawback of using electron spins in a GaAs environment is the short spin coherence time, which is measured to be in the nanosecond range [2,4]. The source of this fast decoherence is the hyperfine interaction of the localized electron spin with the randomly fluctuating nuclear spins of the host lattice. The fluctuations of the nuclear spins have to be reduced to extend the electron spin coherence time. We therefore study the electron-nuclear spin interaction and use magnetically driven spin resonance to control the electron spin and indirectly manipulate the nuclear spins. We apply continuous microwave excitation to the electron spin and observe strong electron-nuclear feedback. One experimental signature of this feedback is the locking of the electron spin system into resonance with the microwaves. Once the electron spin is locked into resonance, this resonance condition remains fullfilled even when the external magnetic field or the microwave frequency is changed. This is due to dynamically build up nuclear polarizations (up to 500 mT) which generally counteract the external magnetic field. Locking of the electron spin system into resonance might indicate that the nuclear polarization exhibits stable configurations where fluctuations of the nuclear distribution are reduced [5]. [4pt] References [0pt] [1] J. M. Elzerman et al. , Nature 430, 431 (2004) [0pt] [2]. J. R. Petta et al., Science 309, 2180 (2005). [0pt] [3] F. H. L. Koppens et al., Nature 442, 766 (2006). [0pt] [4] F. H. L. Koppens et al., Phys. Rev. Lett. 100, 236802 (2008). [0pt] [5] J. Danon and Yu. V. Nazarov, private communication.

  9. The Microwave Spectrum of Imidazole; Complete Structure and the Electron Distribution from Nuclear Quadrupole Coupling Tensors and Dipole Moment Orientation

    NASA Astrophysics Data System (ADS)

    Christen, Dines; Griffiths, John H.; Sheridan, John

    1981-12-01

    Spectra have been measured for eleven isotopic forms of imidazole, including single substitutions at each nucleus in turn. A complete rs-structure is obtained. The ring structure is: N(1)-C(2) = 1.364 Å, C(2)-N(3) = 1.314 Å, N(3)-C(4) = 1.382 Å, C(4)-C(5) = 1.364 Å, C(5)-N(1) = 1.377 Å, ≮N(1)C(2)N(3) = 112.0°, ≮C(2)N(3)C(4) = 104.9°, ≮N(3)C(4)C(5) = 110.7°, ≮C(4)C(5)N(1) = 105.5° and ≮C(5)N(1)C(2) = 106.9°. The N(1)-H(1) distance is 0.998 Å, while the C-H distances are all very close to 1.078 Å. The bonds N(1)-H(1) and C(2)-H(2) lie close to the external bisectors of the respective ring angles, but C(4)-H(4) and C(5)-H(5) are each displaced by several degrees from these bisectors towards N(3) and N(1) respectively. The electric dipole moment is established as 3.67 (5) D from Stark effects, directed almost parallel with the line joining the nitrogen nuclei. The properties and orientations of the two 14N-nuclear quadrupole tensors have been investigated, in particular through the spectra of the two mono-14N-imidazoles.

  10. Nuclear quadrupole resonance: a technique to control hydration processes in the pharmaceutical industry.

    PubMed

    Limandri, Silvina; Visñovezky, Claudia; Pérez, Silvina C; Schurrer, Clemar A; Wolfenson, Alberto E; Ferro, Maribel; Cuffini, Silvia L; de Souza, Joel Gonçalves; Aguiar, F Armani; de Gaitani, C Masetto

    2011-03-01

    Pharmaceuticals can exist in many solid forms, which can have different physical and chemical properties. These solid forms include polymorphs, solvates, amorphous, and hydrates. Particularly, hydration process can be quite common since pharmaceutical solids can be in contact with water during manufacturing process and can also be exposed to water during storage. In the present work, it is proved that NQR technique is capable of detecting different hydrated forms not only in the pure raw material but also in the final product (tablets), being in this way a useful technique for quality control. This technique was also used to study the dehydration process from pentahydrate to trihydrate.

  11. The study of polymorphic states of paradichlorobenzene by means of nuclear quadrupole resonance relaxometry.

    PubMed

    Sinyavsky, N Ya; Mershiev, I G; Kupriyanova, G S

    2016-09-01

    The article describes the results of the experimental study of the molecular crystal of paradichlorobenzene in α- and β-phases by means of NQR-relaxometry with the inversion of Laplace transformation. The anisotropy effect of the pore space of wood on the distribution of times of the spin-lattice relaxation of p-C6H4Cl2 in the pores of pre-impregnated with the molten sample is shown. It was established that the increase in the T1 spin-lattice relaxation time of (35)Cl nucleus in the wood pores (channels) is observed in the case when the radio frequency field B1 is parallel to the tracheid's of wood. The NQR T1ρ dispersion analysis of paradichlorobenzene in α-phase was carried out for the first time. PMID:27494233

  12. Nuclear magnetic resonance in environmental engineering: principles and applications.

    PubMed

    Lens, P N; Hemminga, M A

    1998-01-01

    This paper gives an introduction to nuclear magnetic resonance spectroscopy (NMR) and magnetic resonance imaging (MRI) in relation to applications in the field of environmental science and engineering. The underlying principles of high resolution solution and solid state NMR, relaxation time measurements and imaging are presented. Then, the use of NMR is illustrated and reviewed in studies of biodegradation and biotransformation of soluble and solid organic matter, removal of nutrients and xenobiotics, fate of heavy metal ions, and transport processes in bioreactor systems.

  13. Resonant microwave cavity for 8.5-12 GHz optically detected electron spin resonance with simultaneous nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Colton, J. S.; Wienkes, L. R.

    2009-03-01

    We present a newly developed microwave resonant cavity for use in optically detected magnetic resonance (ODMR) experiments. The cylindrical quasi-TE011 mode cavity is designed to fit in a 1 in. magnet bore to allow the sample to be optically accessed and to have an adjustable resonant frequency between 8.5 and 12 GHz. The cavity uses cylinders of high dielectric material, so-called "dielectric resonators," in a double-stacked configuration to determine the resonant frequency. Wires in a pseudo-Helmholtz configuration are incorporated into the cavity to provide frequencies for simultaneous nuclear magnetic resonance (NMR). The system was tested by measuring cavity absorption as microwave frequencies were swept, by performing ODMR on a zinc-doped InP sample, and by performing optically detected NMR on a GaAs sample. The results confirm the suitability of the cavity for ODMR with simultaneous NMR.

  14. Charge dependence and electric quadrupole effects on single-nucleon removal in relativistic and intermediate energy nuclear collisions

    NASA Technical Reports Server (NTRS)

    Norbury, J. W.; Townsend, L. W. (Principal Investigator)

    1990-01-01

    Single-nucleon removal in relativistic and intermediate energy nucleus-nucleus collisions is studied using a generalization of Weizsacker-Williams theory that treats each electromagnetic multipole separately. Calculations are presented for electric dipole and quadrupole excitations and incorporate a realistic minimum impact parameter, Coulomb recoil corrections, and the uncertainties in the input photonuclear data. Discrepancies are discussed. The maximum quadrupole effect to be observed in future experiments is estimated and also an analysis of the charge dependence of the electromagnetic cross sections down to energies as low as 100 MeV/nucleon is made.

  15. Charge Dependence and Electric Quadrupole Effects on Single-Nucleon Removal in Relativistic and Intermediate Energy Nuclear Collisions

    NASA Technical Reports Server (NTRS)

    Norbury, John W.

    1992-01-01

    Single nucleon removal in relativistic and intermediate energy nucleus-nucleus collisions is studied using a generalization of Weizsacker-Williams theory that treats each electromagnetic multipole separately. Calculations are presented for electric dipole and quadrupole excitations and incorporate a realistic minimum impact parameter, Coulomb recoil corrections, and the uncertainties in the input photonuclear data. Discrepancies are discussed. The maximum quadrupole effect to be observed in future experiments is estimated and also an analysis of the charge dependence of the electromagnetic cross sections down to energies as low as 100 MeV/nucleon is made.

  16. Probing vibrational anisotropy with nuclear resonance vibrational spectroscopy.

    SciTech Connect

    Pavlik, J. W.; Barabanschikov, A.; Oliver, A. G.; Alp, E. E.; Sturhahn, W.; Zhao, J.; Sage, J. T.; Scheidt, W. R.

    2010-06-14

    A NRVS single-crystal study (NRVS=nuclear resonance vibrational spectroscopy) has provided detailed information on the in-plane modes of nitrosyl iron porphyrinate [Fe(oep)(NO)] (see picture; oep=octaethylporphyrin). The axial nitrosyl ligand controls the direction of the in-plane iron motion.

  17. Landau zeroth-sound and nuclear giant resonances

    NASA Astrophysics Data System (ADS)

    Strutinsky, V.; Magner, A.; Denisov, V.

    1984-10-01

    Analytical solution for the zeroth-sound in the infinite matter is used as a basis for constructing the distribution functions in finite-size nuclei. Simple characteristic equation is obtained which determines frequencies of isoscalar nuclear giant resonances due to the zeroth-sound modes coupled to the surface distortions.

  18. Nuclear resonant scattering beamline at the Advanced Photon Source

    SciTech Connect

    Alp, E.E.; Mooney, T.M.; Toellner, T.; Sturhahn, W.

    1993-09-01

    The principal and engineering aspects of a dedicated synchrotron radiation beamline under construction at the Advanced Photon Source for nuclear resonant scattering purposes are explained. The expected performance in terms of isotopes to be studied, flux, and timing properties is discussed.

  19. C-13 nuclear magnetic resonance in organic geochemistry.

    NASA Technical Reports Server (NTRS)

    Balogh, B.; Wilson, D. M.; Burlingame, A. L.

    1972-01-01

    Study of C-13 nuclear magnetic resonance (NMR) spectra of polycyclic fused systems. The fingerprint qualities of the natural abundance in C-13 NMR spectra permitting unequivocal identification of these compounds is discussed. The principle of structural additivity of C-13 NMR information is exemplified on alpha and beta androstanes, alpha and beta cholestanes, ergostanes, sitostanes, and isodecanes.

  20. Nuclear Magnetic Resonance Coupling Constants and Electronic Structure in Molecules.

    ERIC Educational Resources Information Center

    Venanzi, Thomas J.

    1982-01-01

    Theory of nuclear magnetic resonance spin-spin coupling constants and nature of the three types of coupling mechanisms contributing to the overall spin-spin coupling constant are reviewed, including carbon-carbon coupling (neither containing a lone pair of electrons) and carbon-nitrogen coupling (one containing a lone pair of electrons).…

  1. Concepts in Biochemistry: Nuclear Magnetic Resonance Spectroscopy in Biochemistry.

    ERIC Educational Resources Information Center

    Cheatham, Steve

    1989-01-01

    Discusses the nature of a nuclear magnetic resonance (NMR) experiment, the techniques used, the types of structural and dynamic information obtained, and how one can view and refine structures using computer graphics techniques in combination with NMR data. Provides several spectra and a computer graphics image from B-form DNA. (MVL)

  2. High-Resolution Nuclear Magnetic Resonance of Solids.

    ERIC Educational Resources Information Center

    Maciel, Gary E.

    1984-01-01

    Examines recent developments in techniques for obtaining high-resolution nuclear magnetic resonance (NMR) spectra on solid samples, discussing the kinds of applications for which these techniques are well suited. Also discusses the characteristics of NMR of solids and generating magnetization for NMR in solids. (JN)

  3. Introduction to nuclear resonant scattering with synchrotron radiation

    SciTech Connect

    Sturhahn, W.; Alp, E.E.; Toellner, T.S.; Hession, P.; Hu, M.; Sutter, J.

    1997-08-01

    In recent years, the use of synchrotron radiation has enjoyed increasing interest in applications to topics of Moessbauer spectroscopy. The development was initiated by the pioneering experimental work of Gerdau et al. following the original proposal of Ruby to use synchrotron radiation for the excitation of low energy nuclear resonances. From the early experiments it was clear that synchrotron radiation experiments with nuclear resonances would only succeed if familiar energy resolved measurements were replaced with a new time resolved technique. During the last decade, the authors experienced the refinement of this novel method for obtaining hyperfine parameters. This exciting development-materialized because of more intense synchrotron radiation sources at the European Synchrotron Radiation Facility (ESRF) and at the Advanced Photon Source (APS), powerful new avalanche photo diode detectors, and improved high energy resolution monochromators. Simultaneously the tools for evaluation of the novel time spectra were created, e.g., Sturhahn and Gerdau developed extensive computer codes based on the theoretical descriptions of Hannon and Trammel. Many beautiful demonstrations of the basic features of the coherent elastic scattering channel using Bragg- and Laue-reflections from single crystals deepened the understanding of nuclear resonant scattering. The concepts leading to the application of synchrotron radiation to elastic and inelastic nuclear resonant scattering are discussed. The resulting new experimental techniques are compared to conventional Moessbauer spectroscopy. A survey of situations that favor experiments with synchrotron radiation is offered.

  4. Using Nuclear Magnetic Resonance Spectroscopy for Measuring Ternary Phase Diagrams

    ERIC Educational Resources Information Center

    Woodworth, Jennifer K.; Terrance, Jacob C.; Hoffmann, Markus M.

    2006-01-01

    A laboratory experiment is presented for the upper-level undergraduate physical chemistry curriculum in which the ternary phase diagram of water, 1-propanol and n-heptane is measured using proton nuclear magnetic resonance (NMR) spectroscopy. The experiment builds upon basic concepts of NMR spectral analysis, typically taught in the undergraduate…

  5. {sup 63}Cu and {sup 197}Au nuclear quadrupole moments from four-component relativistic density-functional calculations using correct long-range exchange

    SciTech Connect

    Thierfelder, Christian; Schwerdtfeger, Peter; Saue, Trond

    2007-09-15

    The electric field gradient in late transition metal compounds is incorrectly determined by most density functionals. We show that the coupling of short-range density functional based with long-range wave function based methods using a reparametrization of the Coulomb-attenuated Becke three-parameter Lee-Yang-Parr approximation gives reliable results for the electric field gradients of copper and gold for a series of compounds. This results in nuclear quadrupole moments of -0.208 b for {sup 63}Cu and +0.526 b for {sup 197}Au in good agreement with experimental values of -0.220(15) and +0.547(16)b, respectively.

  6. Rotational resonance with multiple-pulse scaling in solid-state nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Spencer, Richard G. S.; Fishbein, Kenneth W.; Levitt, Malcolm H.; Griffin, Robert G.

    1994-04-01

    Multiple-pulse techniques are applied to rotational resonance experiments in solid-state nuclear magnetic resonance. The usual rotational resonance condition is satisfied when an integral multiple of the magic-angle spinning speed equals the difference in isotropic chemical shifts of the two members of a homonuclear spin-1/2 pair. We show that sequences of rapid periodic radio-frequency pulses scale and rotate both the Zeeman and dipole-dipole Hamiltonians, leading to a modification of the resonance condition and to the introduction of new, single- and double-quantum, rotational resonances. Experimental results are presented which demonstrate these effects in the spectra of doubly 13C-labeled solids.

  7. In vivo nuclear magnetic resonance imaging

    NASA Technical Reports Server (NTRS)

    Leblanc, A.

    1986-01-01

    During the past year the Woodlands Baylor Magnetic Resonance Imaging (MRI) facility became fully operational. A detailed description of this facility is given. One significant instrument addition this year was the 100 MHz, 40cm bore superconducting imaging spectrometer. This instrument gives researchers the capability to acquire high energy phosphate spectra. This will be used to investigate ATP, phosphocreatinine and inorganic phosphate changes in normal and atrophied muscle before, during and after exercise. An exercise device for use within the bore of the imaging magnet is under design/construction. The results of a study of T sub 1 and T sub 2 changes in atrophied muscle in animals and human subjects are given. The imaging and analysis of the lower leg of 15 research subjects before and after 5 weeks of complete bedrest was completed. A compilation of these results are attached.

  8. Nuclear magnetic resonance imaging in patients with cardiac pacing devices.

    PubMed

    Buendía, Francisco; Sánchez-Gómez, Juan M; Sancho-Tello, María J; Olagüe, José; Osca, Joaquín; Cano, Oscar; Arnau, Miguel A; Igual, Begoña

    2010-06-01

    Currently, nuclear magnetic resonance imaging is contraindicated in patients with a pacemaker or implantable cardioverter-defibrillator. This study was carried out because the potential risks in this situation need to be clearly defined. This prospective study evaluated clinical and electrical parameters before and after magnetic resonance imaging was performed in 33 patients (five with implantable cardioverter-defibrillators and 28 with pacemakers). In these patients, magnetic resonance imaging was considered clinically essential. There were no clinical complications. There was a temporary communication failure in two cases, sensing errors during imaging in two cases, and a safety signal was generated in one pacemaker at the maximum magnetic resonance frequency and output level. There were no technical restrictions on imaging nor were there any permanent changes in the performance of the cardiac pacing device. PMID:20515632

  9. Nuclear magnetic resonance imaging with 90-nm resolution.

    PubMed

    Mamin, H J; Poggio, M; Degen, C L; Rugar, D

    2007-05-01

    Magnetic resonance imaging (MRI) is a powerful imaging technique that typically operates on the scale of millimetres to micrometres. Conventional MRI is based on the manipulation of nuclear spins with radio-frequency fields, and the subsequent detection of spins with induction-based techniques. An alternative approach, magnetic resonance force microscopy (MRFM), uses force detection to overcome the sensitivity limitations of conventional MRI. Here, we show that the two-dimensional imaging of nuclear spins can be extended to a spatial resolution better than 100 nm using MRFM. The imaging of 19F nuclei in a patterned CaF(2) test object was enabled by a detection sensitivity of roughly 1,200 nuclear spins at a temperature of 600 mK. To achieve this sensitivity, we developed high-moment magnetic tips that produced field gradients up to 1.4 x 10(6) T m(-1), and implemented a measurement protocol based on force-gradient detection of naturally occurring spin fluctuations. The resulting detection volume was less than 650 zeptolitres. This is 60,000 times smaller than the previous smallest volume for nuclear magnetic resonance microscopy, and demonstrates the feasibility of pushing MRI into the nanoscale regime.

  10. Polarization of nuclear spins by a cold nanoscale resonator

    SciTech Connect

    Butler, Mark C.; Weitekamp, Daniel P.

    2011-12-15

    A cold nanoscale resonator coupled to a system of nuclear spins can induce spin relaxation. In the low-temperature limit where spin-lattice interactions are ''frozen out,'' spontaneous emission by nuclear spins into a resonant mechanical mode can become the dominant mechanism for cooling the spins to thermal equilibrium with their environment. We provide a theoretical framework for the study of resonator-induced cooling of nuclear spins in this low-temperature regime. Relaxation equations are derived from first principles, in the limit where energy donated by the spins to the resonator is quickly dissipated into the cold bath that damps it. A physical interpretation of the processes contributing to spin polarization is given. For a system of spins that have identical couplings to the resonator, the interaction Hamiltonian conserves spin angular momentum, and the resonator cannot relax the spins to thermal equilibrium unless this symmetry is broken by the spin Hamiltonian. The mechanism by which such a spin system becomes ''trapped'' away from thermal equilibrium can be visualized using a semiclassical model, which shows how an indirect spin-spin interaction arises from the coupling of multiple spins to one resonator. The internal spin Hamiltonian can affect the polarization process in two ways: (1) By modifying the structure of the spin-spin correlations in the energy eigenstates, and (2) by splitting the degeneracy within a manifold of energy eigenstates, so that zero-frequency off-diagonal terms in the density matrix are converted to oscillating coherences. Shifting the frequencies of these coherences sufficiently far from zero suppresses the development of resonator-induced correlations within the manifold during polarization from a totally disordered state. Modification of the spin-spin correlations by means of either mechanism affects the strength of the fluctuating spin dipole that drives the resonator. In the case where product states can be chosen as energy

  11. Algorithmic cooling in liquid-state nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Atia, Yosi; Elias, Yuval; Mor, Tal; Weinstein, Yossi

    2016-01-01

    Algorithmic cooling is a method that employs thermalization to increase qubit purification level; namely, it reduces the qubit system's entropy. We utilized gradient ascent pulse engineering, an optimal control algorithm, to implement algorithmic cooling in liquid-state nuclear magnetic resonance. Various cooling algorithms were applied onto the three qubits of C132-trichloroethylene, cooling the system beyond Shannon's entropy bound in several different ways. In particular, in one experiment a carbon qubit was cooled by a factor of 4.61. This work is a step towards potentially integrating tools of NMR quantum computing into in vivo magnetic-resonance spectroscopy.

  12. Benchmark calculations on the nuclear quadrupole-coupling parameters for open-shell molecules using non-relativistic and scalar-relativistic coupled-cluster methods

    SciTech Connect

    Cheng, Lan

    2015-08-14

    Quantum-chemical computations of nuclear quadrupole-coupling parameters for 24 open-shell states of small molecules based on non-relativistic and spin-free exact two-component (SFX2C) relativistic equation-of-motion coupled-cluster (EOM-CC) as well as spin-orbital-based restricted open-shell Hartree-Fock coupled-cluster (ROHF-CC) methods are reported. Relativistic effects, the performance of the EOM-CC and ROHF-CC methods for treating electron correlation, as well as basis-set convergence have been carefully analyzed. Consideration of relativistic effects is necessary for accurate calculations on systems containing third-row (K-Kr) and heavier elements, as expected, and the SFX2C approach is shown to be a useful cost-effective option here. Further, it is demonstrated that the EOM-CC methods constitute flexible and accurate alternatives to the ROHF-CC methods in the calculations of nuclear quadrupole-coupling parameters for open-shell states.

  13. Deuterium nuclear magnetic resonance unambiguously quantifies pore and collagen-bound water in cortical bone

    PubMed Central

    Ong, Henry H.; Wright, Alexander C.; Wehrli, Felix W.

    2012-01-01

    Bone water (BW) plays a pivotal role in nutrient transport and conferring bone with its viscoelastic mechanical properties. BW is partitioned between the pore spaces of the Haversian and lacuno-canalicular system, and water predominantly bound to the matrix proteins (essentially collagen). The general model of BW is that the former predominantly experiences fast isotropic molecular reorientation, whereas water in the bone matrix undergoes slower anisotropic rotational diffusion. Here, we provide direct evidence for the correctness of this model and show that unambiguous quantification in situ of these two functionally and dynamically different BW fractions is possible. The approach chosen relies on nuclear magnetic resonance (NMR) of deuterium (2H) that unambiguously separates and quantifies the two fractions on the basis of their distinguishing microdynamic properties. Twenty-four specimens of the human tibial cortex from six donors (3 male, 3 female, ages 27-83 years) were cored and 2H spectra recorded at 62 MHz (9.4 Tesla) on a Bruker Instruments DMX 400 spectrometer after exchange of native BW with 2H2O. Spectra consisted of a doublet signal resulting from quadrupole interaction of water bound to collagen. Doublet splittings were found to depend on the orientation of the osteonal axis with respect to the magnetic field direction (8.2 and 4.3 kHz for parallel and perpendicular orientation, respectively). In contrast, the isotropically reorienting pore-resident water yielded a single resonance line superimposed on the doublet. Nulling of the singlet resonance allowed separation of the two fractions. The results indicate that in human cortical bone 60-80% of detectable BW is collagen-bound. Porosity determined as the difference between total BW and collagen bound water fraction was found to strongly parallel μCT based measurements (R2 = 0.91). Our method provides means for direct validation of emerging relaxation-based measurements of cortical bone porosity by

  14. Coupling of nuclear quadrupole and octupole degrees of freedom in an angular momentum dependent potential of two deformation variables

    SciTech Connect

    Minkov, N.; Yotov, P.; Drenska, S.; Scheid, W.; Bonatsos, Dennis; Lenis, D.; Petrellis, D.

    2006-04-26

    We propose a collective rotation-vibration Hamiltonian of nuclei in which the axial quadrupole {beta}2 and octupole {beta}3 variables are coupled through the centrifugal interaction. We consider that the system oscillates between positive and negative {beta}3-values by rounding a potential core in the ({beta}2,{beta}3)- space. We examine the effect of the 'rounding' in the structure of the spectrum.

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

    PubMed

    Guendouz, 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

  16. Probing soil and aquifer material porosity with nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Hinedi, Z. R.; Kabala, Z. J.; Skaggs, T. H.; Borchardt, D. B.; Lee, R. W. K.; Chang, A. C.

    1993-12-01

    Nuclear magnetic resonance relaxation measurements were used to identify different characteristic porosity domains in soil and aquifer materials. The porosity distribution can be inferred from these measurements by a regularization method applicable to any nuclear magnetic resonance (NMR) relaxation, or by an analytic method applicable only to multiexponential relaxations (D. Orazio et al., 1989). The porosity distribution obtained from NMR relaxation measurements strongly depends on the pore shape factor. For the Borden aquifer material, both the regularized and the analytic pore size distribution obtained from NMR relaxation measurements are consistent with those obtained by Ball et al. (1990) using Hg porosimetry and N2 adsorption. For the Eustis and the Webster soils, the measured porosity domains are qualitatively consistent with those expected based on their respective composition. Our findings suggest that due to the long time required to saturate fine pores, NMR measurements of porosity distribution that are collected at short saturation times are biased toward larger pore sizes.

  17. Chemometric Analysis of Nuclear Magnetic Resonance Spectroscopy Data

    SciTech Connect

    ALAM,TODD M.; ALAM,M. KATHLEEN

    2000-07-20

    Chemometric analysis of nuclear magnetic resonance (NMR) spectroscopy has increased dramatically in recent years. A variety of different chemometric techniques have been applied to a wide range of problems in food, agricultural, medical, process and industrial systems. This article gives a brief review of chemometric analysis of NMR spectral data, including a summary of the types of mixtures and experiments analyzed with chemometric techniques. Common experimental problems encountered during the chemometric analysis of NMR data are also discussed.

  18. High field nuclear magnetic resonance in transition metal substituted BaFe2As2

    NASA Astrophysics Data System (ADS)

    Garitezi, T. M.; Lesseux, G. G.; Rosa, P. F. S.; Adriano, C.; Reyes, A. P.; Kuhns, P. L.; Pagliuso, P. G.; Urbano, R. R.

    2014-05-01

    We report high field 75As nuclear magnetic resonance (NMR) measurements on Co and Cu substituted BaFe2As2 single crystals displaying same structural/magnetic transition T0≃128 K. From our anisotropy studies in the paramagnetic state, we strikingly found virtually identical quadrupolar splitting and consequently the quadrupole frequency νQ≃2.57(1) MHz for both compounds, despite the claim that each Cu delivers 2 extra 3d electrons in BaFe2As2 compared to Co substitution. These results allow us to conclude that a subtle change in the crystallographic structure, particularly in the Fe-As tetrahedra, must be the most probable tuning parameter to determine T0 in this class of superconductors rather than electronic doping. Furthermore, our NMR data around T0 suggest coexistence of tetragonal/paramagnetic and orthorhombic/antiferromagnetic phases between the structural and the spin density wave magnetic phase transitions, similarly to what was reported for K-doped BaFe2As2 [Urbano et al., Phys. Rev. Lett. 105, 107001 (2010)].

  19. Characterization of urban aerosol using aerosol mass spectrometry and proton nuclear magnetic resonance spectroscopy

    NASA Astrophysics Data System (ADS)

    Cleveland, M. J.; Ziemba, L. D.; Griffin, R. J.; Dibb, J. E.; Anderson, C. H.; Lefer, B.; Rappenglück, B.

    2012-07-01

    Particulate matter was measured during August and September of 2006 in Houston as part of the Texas Air Quality Study II Radical and Aerosol Measurement Project. Aerosol size and composition were determined using an Aerodyne quadrupole aerosol mass spectrometer. Aerosol was dominated by sulfate (4.1 ± 2.6 μg m-3) and organic material (5.5 ± 4.0 μg m-3), with contributions of organic material from both primary (˜32%) and secondary (˜68%) sources. Secondary organic aerosol appears to be formed locally. In addition, 29 aerosol filter samples were analyzed using proton nuclear magnetic resonance (1H NMR) spectroscopy to determine relative concentrations of organic functional groups. Houston aerosols are less oxidized than those observed elsewhere, with smaller relative contributions of carbon-oxygen double bonds. These particles do not fit 1H NMR source apportionment fingerprints for identification of secondary, marine, and biomass burning organic aerosol, suggesting that a new fingerprint for highly urbanized and industrially influenced locations be established.

  20. The Iodine Hvperfine Structure in the Microwave Spectrum of Ethyl Iodide: Nuclear Quadrupole and Spin Rotation Coupling

    NASA Astrophysics Data System (ADS)

    Lee, W. W.; Scherr, Lawrence M.; Barsh, Max K.

    1988-11-01

    Some rotational transitions of ethyl iodide, CH3CH2I, have been reinvestigated by microwave Fourier transform (MWFT) spectroscopy. The iodine hyperfine structure splittings were first ana lyzed using a direct diagonalization procedure of the complete quadrupole Hamiltonian matrix. The results of this analysis showed deviations from our measurements up to 60 kHz. A new analysis using additional spin rotation coupling matrix elements reproduces our measurements within the experi­mental error limit and decreases the standard deviation of the least squares fit from 28 kHz to only 4 kHz.

  1. Hyperfine and Nuclear Quadrupole Tensors of Nitrogen Donors in the QA Site of Bacterial Reaction Centers: Correlation of the Histidine Nδ Tensors with Hydrogen Bond Strength

    PubMed Central

    2015-01-01

    X- and Q-band pulsed EPR spectroscopy was applied to study the interaction of the QA site semiquinone (SQA) with nitrogens from the local protein environment in natural abundance 14N and in 15N uniformly labeled photosynthetic reaction centers of Rhodobacter sphaeroides. The hyperfine and nuclear quadrupole tensors for His-M219 Nδ and Ala-M260 peptide nitrogen (Np) were estimated through simultaneous simulation of the Q-band 15N Davies ENDOR, X- and Q-band 14,15N HYSCORE, and X-band 14N three-pulse ESEEM spectra, with support from DFT calculations. The hyperfine coupling constants were found to be a(14N) = 2.3 MHz, T = 0.3 MHz for His-M219 Nδ and a(14N) = 2.6 MHz, T = 0.3 MHz for Ala-M260 Np. Despite that His-M219 Nδ is established as the stronger of the two H-bond donors, Ala-M260 Np is found to have the larger value of a(14N). The nuclear quadrupole coupling constants were estimated as e2Qq/4h = 0.38 MHz, η = 0.97 and e2Qq/4h = 0.74 MHz, η = 0.59 for His-M219 Nδ and Ala-M260 Np, respectively. An analysis of the available data on nuclear quadrupole tensors for imidazole nitrogens found in semiquinone-binding proteins and copper complexes reveals these systems share similar electron occupancies of the protonated nitrogen orbitals. By applying the Townes–Dailey model, developed previously for copper complexes, to the semiquinones, we find the asymmetry parameter η to be a sensitive probe of the histidine Nδ–semiquinone hydrogen bond strength. This is supported by a strong correlation observed between η and the isotropic coupling constant a(14N) and is consistent with previous computational works and our own semiquinone-histidine model calculations. The empirical relationship presented here for a(14N) and η will provide an important structural characterization tool in future studies of semiquinone-binding proteins. PMID:25026433

  2. An inductively coupled, doubly tuned resonator for in vivo nuclear magnetic resonance spectroscopy

    NASA Astrophysics Data System (ADS)

    McNichols, Roger J.; Wright, Steven M.; Wasser, Jeremy S.; Coté, Gerard L.

    1999-08-01

    We present a coil designed for in vivo 31P and 1H nuclear magnetic resonance spectroscopy which consists of a doubly tuned resonator inductively coupled to separate 1H and 31P feed coils. The advantages of the resonator include the ability to 1H shim over the same volume from which 31P spectra are extracted by using a single sample coil, elimination of coupling problems between separate 1H and 31P coils, ease of design and tuning over conventional double-tuned coils, and reduced match/tune sensitivity to coil loading, which is important in in vivo applications. We have used this coil to collect phosphorus spectra from the in situ heart of the western painted turtle (Chrysemys picta bellii) at 2 T. The total heart volume was less than 1 mL and acquisition time was just under 10 min.

  3. A loop-gap resonator for chirality-sensitive nuclear magneto-electric resonance (NMER).

    PubMed

    Garbacz, Piotr; Fischer, Peer; Krämer, Steffen

    2016-09-14

    Direct detection of molecular chirality is practically impossible by methods of standard nuclear magnetic resonance (NMR) that is based on interactions involving magnetic-dipole and magnetic-field operators. However, theoretical studies provide a possible direct probe of chirality by exploiting an enantiomer selective additional coupling involving magnetic-dipole, magnetic-field, and electric field operators. This offers a way for direct experimental detection of chirality by nuclear magneto-electric resonance (NMER). This method uses both resonant magnetic and electric radiofrequency (RF) fields. The weakness of the chiral interaction though requires a large electric RF field and a small transverse RF magnetic field over the sample volume, which is a non-trivial constraint. In this study, we present a detailed study of the NMER concept and a possible experimental realization based on a loop-gap resonator. For this original device, the basic principle and numerical studies as well as fabrication and measurements of the frequency dependence of the scattering parameter are reported. By simulating the NMER spin dynamics for our device and taking the (19)F NMER signal of enantiomer-pure 1,1,1-trifluoropropan-2-ol, we predict a chirality induced NMER signal that accounts for 1%-5% of the standard achiral NMR signal. PMID:27634253

  4. A loop-gap resonator for chirality-sensitive nuclear magneto-electric resonance (NMER)

    NASA Astrophysics Data System (ADS)

    Garbacz, Piotr; Fischer, Peer; Krämer, Steffen

    2016-09-01

    Direct detection of molecular chirality is practically impossible by methods of standard nuclear magnetic resonance (NMR) that is based on interactions involving magnetic-dipole and magnetic-field operators. However, theoretical studies provide a possible direct probe of chirality by exploiting an enantiomer selective additional coupling involving magnetic-dipole, magnetic-field, and electric field operators. This offers a way for direct experimental detection of chirality by nuclear magneto-electric resonance (NMER). This method uses both resonant magnetic and electric radiofrequency (RF) fields. The weakness of the chiral interaction though requires a large electric RF field and a small transverse RF magnetic field over the sample volume, which is a non-trivial constraint. In this study, we present a detailed study of the NMER concept and a possible experimental realization based on a loop-gap resonator. For this original device, the basic principle and numerical studies as well as fabrication and measurements of the frequency dependence of the scattering parameter are reported. By simulating the NMER spin dynamics for our device and taking the 19F NMER signal of enantiomer-pure 1,1,1-trifluoropropan-2-ol, we predict a chirality induced NMER signal that accounts for 1%-5% of the standard achiral NMR signal.

  5. In-vivo study of the nuclear quadrupole interaction of99Mo (β- 99)Tc in nitrogenase of Klebsiella pneumoniaein nitrogenase of Klebsiella pneumoniae

    NASA Astrophysics Data System (ADS)

    Mottner, P.; Lerf, A.; Ni, X.; Butz, T.; Erfkamp, J.; Müller, A.

    1990-08-01

    We report on the first TDPAC-measurements of the nuclear quadrupole interaction (NQI) of (NQI) of99Mo(β-)99Tc in the nitrogenase of the bacteria Klebsiella pneumoniae. Because nitrogenase is the only Mo-containing enzyme in Klebsiella pneumoniae under the chosen conditions, no further isolation of this enzyme was necessary. The majority of the incorporated99Mo is subjected to a well defined NQI with ω=365(7) Mrad/s, η=1 and a reorientational correlation time of τcoττ≈10nsec and is attributed to the active site of the FeMo cofactor. During sample preparation we noted a pronounced affinity of the bacteria to99mTc.

  6. Enabling in situ thermometry using transmission nuclear resonance fluorescence

    NASA Astrophysics Data System (ADS)

    Angell, Christopher T.

    2016-02-01

    Transmission nuclear resonance fluorescence (NRF) has been proposed for use as an assay and detection technique for nuclear security and safeguards applications because of its isotope-specific sensitivity and the penetrating capability of γ -rays. It can also be used for in situ thermometry because the absorbing resonance profile is sensitive to temperature. Using transmission NRF for thermometry could provide a new avenue for studying the ion temperature evolution of laser-induced plasmas using the upcoming ELI-NP facility. It could also be used for applications where thermometry would be otherwise infeasible, such as for determining the average fuel temperature of spent nuclear fuel, a step that would reduce the assay uncertainty using transmission NRF. In this paper, two different transmission NRF thermometry scenarios are presented and analyzed for sensitivity. This analysis demonstrated that thermometry using γ -rays is possible independent of γ -ray beam type and will be feasible with next-generation high-intensity γ -ray sources. Beyond thermometry, an application of temperature effects was found in the improvement of transmission NRF efficacy for assay and detection: using a cryogenic witness target will reduce the required measurement time by 40%.

  7. 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

  8. Cantilever noise in off-cantilever-resonance force-detected nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Harrell, Lee E.; Thurber, Kent R.; Smith, Doran D.

    2004-03-01

    Early work in force-detected nuclear magnetic resonance (FD-NMR) and magnetic resonance force microscopy was restricted to nuclei with a relatively large gyromagnetic ratio γ. Increasingly, as researchers look to apply FD-NMR to practical problems, observing isotopes with a small γ is becoming necessary. The small γ of these isotopes places severe restrictions on the radio frequency field strength necessary to flip the sample spins at practical cantilever frequencies by adiabatic rapid passage. These restrictions led us to investigate the feasibility of observing FD-NMR by flipping sample spins at a rate well below the cantilever frequency. In this article we show that there is no increase in thermomechanical force noise in off-cantilever-resonance FD-NMR relative to on-cantilever-resonance work. Further, we show that working off-cantilever resonance can reduce artifacts and decrease data acquisition time. The major disadvantage to working off-cantilever resonance—reduced cantilever response—increases the importance of low noise detection of cantilever oscillation.

  9. Phosphorus nuclear magnetic resonance in isolated perfused rat pancreas

    SciTech Connect

    Matsumoto, Takehisa; Kanno, Tomio; Seo, Yoshiteru; Murakami, Masataka; Watari, Hiroshi National Institute for Physiological Sciences, Okazaki )

    1988-04-01

    Phosphorus nuclear magnetic resonance spectroscopy was applied to measure phosphorus energy metabolites in isolated perfused rat pancreas. The gland was perfused with a modified Krebs-Henseleit solution at room temperature (25{degree}C). {sup 31}P resonances of creatine phosphate (PCr), ATP, ADP, inorganic phosphate (P{sub i}) and phosphomonoesters (PMEs) were observed in all the preparations of pancreas. In different individual preparations, the resonance of PCr varied, but those of ATP were almost the same. The initial levels of PCr and ATP in individual preparations, however, remained almost unchanged during perfusion with the standard solution for 2 h. When the perfusion was stopped, the levels of ATP and PCr decreased, while the levels of PME and P{sub i} increased. At that time, the P{sub i} resonance shfted to a higher magnetic field, indicating that the tissue pH decreased. On reperfusion, the tissue levels of phosphorus compounds and the tissue pH were restored to their initial resting levels. Continuous infusion of 0.1 {mu}M acetylcholine caused marked and sustained increases in the flow of pancreatic juice and protein output. During the stimulation the tissue levels of phosphorus compounds remained unchanged, while the tissue pH was decreased slightly.

  10. Theory of 14N and 17O Nuclear Quadrupole Interactions in the Single Amino Acids Occurring in the Protein Chain of Cytochrome c

    NASA Astrophysics Data System (ADS)

    Scheicher, R. H.; Cammarere, D.; Sahoo, N.; Nagamine, K.; Das, T. P.

    2002-07-01

    The understanding of electron transport in proteins based on a novel technique involving muon spin rotation (μSR)measurements is a topic of great current interest. The technique, which involves study of spin relaxation of a positive muon (μ+) trapped in amino acids in protein chains due to the fluctuating magnetic field that the moving electron produces, is based on the premise that the electron is generated by ionization of a muonium (Mu) which was trapped at the same site as the μ+ left behind. In attempting to test this premise from first-principles for the Cytochrome c (Cyt c) system in which recent μSR measurements have been made, we have carried out Hartree- Fock investigations of the electronic structures of the bare amino acids and amino acids with + and Mu trapped at the oxygen of the C=O group common to all amino acids. With the aim that the comparison of theoretically predicted experimental nuclear quadrupole interaction (NQI) parameters will provide a useful test of the electron distribution in the amino acids of Cyt c, we present results for the nuclear quadrupole coupling constants (e2qQ) and asymmetry parameters (η) for the bare amino acids and the amino acids with trapped μ+ and Mu. The trends in 2 and for 14N and 17O between the various amino acids, as well as the changes in these parameters in the presence of μ+ and Mu are being analyzed. It would be helpful to have experimental data for e2qQ and to η compare with our predictions for the amino acids as they occur in vitro in polycrystalline Cyt c in which the SR measurements have been carried out. It is also hoped that the μSR technique will be able to provide experimental data on e2qQ and for the 14N and 17O nuclei to compare with our predictions

  11. Nuclear magnetic resonance imaging with hyper-polarized noble gases

    SciTech Connect

    Schmidt, D.M.; George, J.S.; Penttila, S.I.; Caprihan, A.

    1997-10-01

    This is the final report of a six-month, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The nuclei of noble gases can be hyper polarized through a laser-driven spin exchange to a degree many orders of magnitude larger than that attainable by thermal polarization without requiring a strong magnetic field. The increased polarization from the laser pumping enables a good nuclear magnetic resonance (NMR) signal from a gas. The main goal of this project was to demonstrate diffusion-weighted imaging of such hyper-polarized noble gas with magnetic resonance imaging (MRI). Possible applications include characterizing porosity of materials and dynamically imaging pressure distributions in biological or acoustical systems.

  12. Nuclear magnetic resonance tomography with a toroid cavity detector

    SciTech Connect

    Woelk, K.; Rathke, J.W.; Klingler, R.J.

    1995-02-01

    A new type of nuclear magnetic resonance (NMR) tomography has been developed at Argonne National Laboratory. The method uses the strong radio frequency field gradient within a cylindrical toroid cavity to provide high-resolution NMR spectral information while simultaneously resolving distances on the micron scale. The toroid cavity imaging technique differs from conventional magnetic resonance imaging (MRI) in that NMR structural information is not lost during signal processing. The new technique could find a wide range of applications in the characterization of surface layers and in the production of advanced materials. Potential areas of application include in situ monitoring of growth sites during ceramic formation processes, analysis of the oxygen annealing step for wires coated with high-temperature superconducting films, and investigation of the reaction chemistry as a function of distance within the diffusion layer for electrochemical processes.

  13. Magnetic-field cycling instrumentation for dynamic nuclear polarization-nuclear magnetic resonance using photoexcited triplets.

    PubMed

    Kagawa, Akinori; Negoro, Makoto; Takeda, Kazuyuki; Kitagawa, Masahiro

    2009-04-01

    To advance static solid-state NMR with hyperpolarized nuclear spins, a system has been developed enabling dynamic nuclear polarization (DNP) using electron spins in the photoexcited triplet state with X-band microwave apparatus, followed by static solid-state nuclear magnetic resonance (NMR) experiments using the polarized nuclear-spin system with a goniometer. In order to perform the DNP and NMR procedures in different magnetic fields, the DNP system and the NMR system are spatially separated, between which the sample can be shuttled while its orientation is controlled in a reproducible fashion. We demonstrate that the system developed in this work is operational for solid-state NMR with hyperpolarized nuclear-spin systems in static organic materials, and also discuss the application of our system.

  14. Evaluation of nitrogen nuclear hyperfine and quadrupole coupling parameters for the proximal imidazole in myoglobin-azide, -cyanide, and -mercaptoethanol complexes by electron spin echo envelope modulation spectroscopy.

    PubMed

    Magliozzo, R S; Peisach, J

    1993-08-24

    Electron spin echo envelope modulation (ESEEM) spectroscopy and computer simulation of spectra has been used to evaluate the nitrogen nuclear hyperfine and quadrupole coupling parameters for the proximal imidazole nitrogen directly coordinated to iron in three low-spin heme complexes, myoglobin-azide, -cyanide, and -mercaptoethanol (MbN3, MbCN, and MbRS). The variability in the weak electron-nuclear coupling parameters reveals the electronic flexibility within the heme group that depends on properties of the exogenous ligands. For example, the isotropic component of the nitrogen nuclear hyperfine coupling ranges from 4.4 MHz for MbN3 to 2.2 MHz for both MbCN and MbRS. The weaker coupling in MbCN and MbRS is taken as evidence for delocalization of unpaired electron spin from iron into the exogenous anionic ligands. The value of e2Qq, the nuclear quadrupole coupling constant for the axial imidazole nitrogen in MbCN and MbRS, was 2.5 MHz but was significantly larger, 3.2 MHz, in MbN3. This large value is considered evidence for a weakened sigma bond between the proximal imidazole and ferric iron in this form, and for a feature contributing to the origin of the high spin-low spin equilibrium exhibited by MbN3 [Beetlestone, J., & George, P. (1964) Biochemistry 5, 707-714]. The ESEEM results have allowed a correlation to be made between the orientation of the g tensor axes, the orientation of the p-pi orbital of the proximal imidazole nitrogen, and sigma- and pi-bonding features of the axial ligands. Furthermore, the proximal imidazole is suggested to act as a pi-acceptor in low-spin heme complexes in order to support strong sigma electron donation from the lone pair orbital to iron. An evaluation of the nitrogen nuclear hyperfine coupling parameters for the porphyrin pyrrole sites in MbRS reveals a large inequivalence in isotropic components consistent with an orientation of rhombic axes (and g tensor axes) that eclipses the Fe-Npyrrole vector directions. PMID:8395204

  15. Nuclear resonance scattering measurement of human iron stores

    SciTech Connect

    Wielopolski, L.; Ancona, R.C.; Mossey, R.T.; Vaswani, A.N.; Cohn, S.H.

    1985-07-01

    Hepatic iron stores were measured noninvasively in 31 patients (thalassemia, hemodialysis, hemosiderosis, refractory anemia) with suspected iron overload, employing a nuclear resonance scattering (NRS) technique. The thalassemia patients were undergoing desferrioxamine chelation therapy during the NRS measurements. The hemodialysis patients were measured before chelation therapy. Iron levels measured by NRS were in general agreement with those determined in liver biopsies by atomic absorption spectroscopy. In addition, NRS measurements from the thorax of some of these patients suggest that this method may also prove useful for clinical assessment of cardiac iron.

  16. Nuclear Magnetic Resonance Applications to Unconventional Fossil Fuel Resources

    NASA Astrophysics Data System (ADS)

    Kleinberg, R. L.; Leu, G.

    2008-12-01

    Technical and economic projections strongly suggest that fossil fuels will continue to play a dominant role in the global energy market through at least the mid twenty-first century. However, low-cost conventional oil and gas will be depleted in that time frame. Therefore new sources of energy will be needed. We discuss two relatively untapped unconventional fossil fuels: heavy oil and gas hydrate. In both cases, nuclear magnetic resonance plays a key role in appraising the resource and providing information needed for designing production processes.

  17. A versatile pulse programmer for pulsed nuclear magnetic resonance spectroscopy.

    NASA Technical Reports Server (NTRS)

    Tarr, C. E.; Nickerson, M. A.

    1972-01-01

    A digital pulse programmer producing the standard pulse sequences required for pulsed nuclear magnetic resonance spectroscopy is described. In addition, a 'saturation burst' sequence, useful in the measurement of long relaxation times in solids, is provided. Both positive and negative 4 V trigger pulses are produced that are fully synchronous with a crystal-controlled time base, and the pulse programmer may be phase-locked with a maximum pulse jitter of 3 ns to the oscillator of a coherent pulse spectrometer. Medium speed TTL integrated circuits are used throughout.

  18. In vivo Carbon-13 Nuclear Magnetic Resonance Studies of Mammals

    NASA Astrophysics Data System (ADS)

    Alger, J. R.; Sillerud, L. O.; Behar, K. L.; Gillies, R. J.; Shulman, R. G.; Gordon, R. E.; Shaw, D.; Hanley, P. E.

    1981-11-01

    Natural abundance carbon-13 nuclear magnetic resonances (NMR) from human arm and rat tissues have been observed in vivo. These signals arise primarily from triglycerides in fatty tissue. Carbon-13 NMR was also used to follow, in a living rat, the conversion of C-1--labeled glucose, which was introduced into the stomach, to C-1--labeled liver glycogen. The carbon-13 sensitivity and resolution obtained shows that natural abundance carbon-13 NMR will be valuable in the study of disorders in fat metabolism, and that experiments with substrates labeled with carbon-13 can be used to study carbohydrate metabolism in vivo.

  19. Flat RF coils in static field gradient nuclear magnetic resonance.

    PubMed

    Stork, H; Gädke, A; Nestle, N; Fujara, F

    2009-10-01

    The use of flat RF coils allows considerable gains in the sensitivity of static field gradient (SFG) nuclear magnetic resonance (NMR) experiments. In this article, this effect is studied theoretically as well as experimentally. Additionally, the flat coil geometry has been studied theoretically depending on magnetic field gradient, pulse sequence and amplifier power. Moreover, detecting the signal directly from the free induction decay (FID) turned out to be quite attractive for STRAFI-like microimaging experiments, especially when using flat coils. In addition to wound rectangular flat coils also spiral flat coils have been developed which can be manufactured by photolithography from printed circuit boards.

  20. Stochastic dipolar recoupling in nuclear magnetic resonance of solids.

    PubMed

    Tycko, Robert

    2007-11-01

    I describe a nuclear magnetic resonance (NMR) technique, called stochastic dipolar recoupling (SDR), that permits continuous experimental control of the character of spin dynamics between coherent and incoherent limits in a system of magnetic dipole-coupled nuclei. In the fully incoherent limit of SDR, spin polarization transfers occur at distance-dependent rates without the quantum mechanical interferences among pairwise dipole-dipole couplings that often limit the feasibility or precision of structural studies of solids by NMR. In addition to facilitating structural studies, SDR represents a possible route to experimental studies of effects of decoherence on the dynamics of quantum many-body systems.

  1. Stochastic Dipolar Recoupling in Nuclear Magnetic Resonance of Solids

    SciTech Connect

    Tycko, Robert

    2007-11-02

    I describe a nuclear magnetic resonance (NMR) technique, called stochastic dipolar recoupling (SDR), that permits continuous experimental control of the character of spin dynamics between coherent and incoherent limits in a system of magnetic dipole-coupled nuclei. In the fully incoherent limit of SDR, spin polarization transfers occur at distance-dependent rates without the quantum mechanical interferences among pairwise dipole-dipole couplings that often limit the feasibility or precision of structural studies of solids by NMR. In addition to facilitating structural studies, SDR represents a possible route to experimental studies of effects of decoherence on the dynamics of quantum many-body system000.

  2. Stochastic dipolar recoupling in nuclear magnetic resonance of solids

    PubMed Central

    Tycko, Robert

    2008-01-01

    I describe a nuclear magnetic resonance (NMR) technique, called stochastic dipolar recoupling (SDR), that permits continuous experimental control of the character of spin dynamics between coherent and incoherent limits in a system of magnetic dipole-coupled nuclei. In the fully incoherent limit of SDR, spin polarization transfers occur at distance-dependent rates without the quantum mechanical interferences among pairwise dipole-dipole couplings that often limit the feasibility or precision of structural studies of solids by NMR. In addition to facilitating structural studies, SDR represents a possible route to experimental studies of effects of decoherence on the dynamics of quantum many-body systems. PMID:17995438

  3. Applications of nuclear magnetic resonance sensors to cultural heritage.

    PubMed

    Proietti, Noemi; Capitani, Donatella; Di Tullio, Valeria

    2014-04-21

    In recent years nuclear magnetic resonance (NMR) sensors have been increasingly applied to investigate, characterize and monitor objects of cultural heritage interest. NMR is not confined to a few specific applications, but rather its use can be successfully extended to a wide number of different cultural heritage issues. A breakthrough has surely been the recent development of portable NMR sensors which can be applied in situ for non-destructive and non-invasive investigations. In this paper three studies illustrating the potential of NMR sensors in this field of research are reported.

  4. Applications of Nuclear Magnetic Resonance Sensors to Cultural Heritage

    PubMed Central

    Proietti, Noemi; Capitani, Donatella; Di Tullio, Valeria

    2014-01-01

    In recent years nuclear magnetic resonance (NMR) sensors have been increasingly applied to investigate, characterize and monitor objects of cultural heritage interest. NMR is not confined to a few specific applications, but rather its use can be successfully extended to a wide number of different cultural heritage issues. A breakthrough has surely been the recent development of portable NMR sensors which can be applied in situ for non-destructive and non-invasive investigations. In this paper three studies illustrating the potential of NMR sensors in this field of research are reported. PMID:24755519

  5. Nuclear magnetic resonance-based quantification of organic diphosphates.

    PubMed

    Lenevich, Stepan; Distefano, Mark D

    2011-01-15

    Phosphorylated compounds are ubiquitous in life. Given their central role, many such substrates and analogs have been prepared for subsequent evaluation. Prior to biological experiments, it is typically necessary to determine the concentration of the target molecule in solution. Here we describe a method where concentrations of stock solutions of organic diphosphates and bisphosphonates are quantified using (31)P nuclear magnetic resonance (NMR) spectroscopy with standard instrumentation using a capillary tube with a secondary standard. The method is specific and is applicable down to a concentration of 200 μM. The capillary tube provides the reference peak for quantification and deuterated solvent for locking. PMID:20833124

  6. Coherent nuclear resonant optics for third generation synchrotron radiation sources

    SciTech Connect

    Alp, E.E.; Mooney, T.M.; Toellner, T.; Homma, H.; Kentjana, M.

    1992-06-01

    The insertion-device-based, third-generation, synchrotron radiation sources now under construction in Europe, the USA, and Japan bring new opportunities and challenges in the design and manufacture of x-ray optics. These high brightness sources provide new opportunities to overcome some of the outstanding problems associated with nuclear resonant monochromatization of synchrotron radiation. New methods such as polarizing monochromators, and zone plates provide alternative methods for production of {mu}eV-neV resolution in the hard x-ray regime. The design principles, and characterization, and performance of crystal monochromators and of nuclear coherent scattering optics, including Grazing Incidence Anti Reflection (GIAR) films, multilayers, zone plates, as well as single crystals are discussed.

  7. Application of nuclear resonance scattering for in vivo measurements

    SciTech Connect

    Wielopolski, L.; Vartsky, D.; Cohn, S.H.

    1983-01-01

    Nuclear resonance scattering is applied in our laboratory to measure hepatic and cardiac iron overload. For iron analysis, a gaseous source of 4 mg MnCl/sub 2/ is introduced into an evacuated quartz vial. Following irradiation in a nuclear reactor, /sup 56/Mn decays by beta emission to the 847-keV level of /sup 56/Fe, which subsequently decays to the ground state of /sup 56/Fe with a 7 ps half-life. The principal aim of this work is to evaluate the efficacy of the iron chelation therapy. Serial measurements over a time period of 6 to 12 months of a given patient will enable us to see how the iron is removed from the critical organs.

  8. Parahydrogen-enhanced zero-field nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Theis, T.; Ganssle, P.; Kervern, G.; Knappe, S.; Kitching, J.; Ledbetter, M. P.; Budker, D.; Pines, A.

    2011-07-01

    Nuclear magnetic resonance, conventionally detected in magnetic fields of several tesla, is a powerful analytical tool for the determination of molecular identity, structure and function. With the advent of prepolarization methods and detection schemes using atomic magnetometers or superconducting quantum interference devices, interest in NMR in fields comparable to the Earth's magnetic field and below (down to zero field) has been revived. Despite the use of superconducting quantum interference devices or atomic magnetometers, low-field NMR typically suffers from low sensitivity compared with conventional high-field NMR. Here we demonstrate direct detection of zero-field NMR signals generated through parahydrogen-induced polarization, enabling high-resolution NMR without the use of any magnets. The sensitivity is sufficient to observe spectra exhibiting 13C-1H scalar nuclear spin-spin couplings (known as J couplings) in compounds with 13C in natural abundance, without the need for signal averaging. The resulting spectra show distinct features that aid chemical fingerprinting.

  9. Nuclear magnetic resonance spectroscopy of the circadian clock of cyanobacteria.

    PubMed

    Chang, Yong-Gang; Tseng, Roger; Kuo, Nai-Wei; LiWang, Andy

    2013-07-01

    The most well-understood circadian clock at the level of molecular mechanisms is that of cyanobacteria. This overview is on how solution-state nuclear magnetic resonance (NMR) spectroscopy has contributed to this understanding. By exciting atomic spin-½ nuclei in a strong magnetic field, NMR obtains information on their chemical environments, inter-nuclear distances, orientations, and motions. NMR protein samples are typically aqueous, often at near-physiological pH, ionic strength, and temperature. The level of information obtainable by NMR depends on the quality of the NMR sample, by which we mean the solubility and stability of proteins. Here, we use examples from our laboratory to illustrate the advantages and limitations of the technique. PMID:23667047

  10. Nuclear-magnetic-resonance quantum calculations of the Jones polynomial

    SciTech Connect

    Marx, Raimund; Spoerl, Andreas; Pomplun, Nikolas; Schulte-Herbrueggen, Thomas; Glaser, Steffen J.; Fahmy, Amr; Kauffman, Louis; Lomonaco, Samuel; Myers, John M.

    2010-03-15

    The repertoire of problems theoretically solvable by a quantum computer recently expanded to include the approximate evaluation of knot invariants, specifically the Jones polynomial. The experimental implementation of this evaluation, however, involves many known experimental challenges. Here we present experimental results for a small-scale approximate evaluation of the Jones polynomial by nuclear magnetic resonance (NMR); in addition, we show how to escape from the limitations of NMR approaches that employ pseudopure states. Specifically, we use two spin-1/2 nuclei of natural abundance chloroform and apply a sequence of unitary transforms representing the trefoil knot, the figure-eight knot, and the Borromean rings. After measuring the nuclear spin state of the molecule in each case, we are able to estimate the value of the Jones polynomial for each of the knots.

  11. Manipulation of the nuclear spin ensemble in a quantum dot with chirped magnetic resonance pulses

    NASA Astrophysics Data System (ADS)

    Munsch, Mathieu; Wüst, Gunter; Kuhlmann, Andreas V.; Xue, Fei; Ludwig, Arne; Reuter, Dirk; Wieck, Andreas D.; Poggio, Martino; Warburton, Richard J.

    2014-09-01

    The nuclear spins in nanostructured semiconductors play a central role in quantum applications. The nuclear spins represent a useful resource for generating local magnetic fields but nuclear spin noise represents a major source of dephasing for spin qubits. Controlling the nuclear spins enhances the resource while suppressing the noise. NMR techniques are challenging: the group III and V isotopes have large spins with widely different gyromagnetic ratios; in strained material there are large atom-dependent quadrupole shifts; and nanoscale NMR is hard to detect. We report NMR on 100,000 nuclear spins of a quantum dot using chirped radiofrequency pulses. Following polarization, we demonstrate a reversal of the nuclear spin. We can flip the nuclear spin back and forth a hundred times. We demonstrate that chirped NMR is a powerful way of determining the chemical composition, the initial nuclear spin temperatures and quadrupole frequency distributions for all the main isotopes. The key observation is a plateau in the NMR signal as a function of sweep rate: we achieve inversion at the first quantum transition for all isotopes simultaneously. These experiments represent a generic technique for manipulating nanoscale inhomogeneous nuclear spin ensembles and open the way to probe the coherence of such mesoscopic systems.

  12. Separation of quadrupolar and chemical/paramagnetic shift interactions in two-dimensional 2H (I=1) nuclear magnetic resonance spectroscopy

    NASA Astrophysics Data System (ADS)

    Antonijevic, Sasa; Wimperis, Stephen

    2005-01-01

    A novel two-dimensional 2H (spin I=1) nuclear magnetic resonance technique is introduced for determination of both quadrupole and chemical/paramagnetic shift tensors and their relative orientation. The new method is based upon the well-known quadrupolar-echo experiment and is designed to refocus the quadrupolar interaction at the end of the t1 evolution period while retaining the modulation introduced by the shift interaction. As a result, a projection of the resulting two-dimensional spectrum onto its F1 dimension yields a shift anisotropy powder lineshape free from any quadrupolar broadening. The chemical/paramagnetic shifts appear in both F1 and F2 dimensions and are thus spread along a +1 frequency gradient; hence, a projection orthogonal to this gradient yields the pure quadrupolar powder lineshape, free from all shift interaction effects. The relative orientation of the quadrupole and shift tensors can be obtained by analysis of the full two-dimensional correlation lineshape. Unlike the well-known double-quantum experiment, the new method is, in principle, equally effective for all values of the quadrupolar splitting, including zero. The properties of the new technique are demonstrated using computer simulation and methods for the extraction of quadrupole and shift tensor parameters are described. The new technique is applied to (diamagnetic) benzoic acid-d1 (C6H5CO2D) and (paramagnetic) copper(II) chloride dihydrate-d4 (CuCl2ṡ2D2O).

  13. Separation of quadrupolar and chemical/paramagnetic shift interactions in two-dimensional 2H (I=1) nuclear magnetic resonance spectroscopy.

    PubMed

    Antonijevic, Sasa; Wimperis, Stephen

    2005-01-22

    A novel two-dimensional (2)H (spin I=1) nuclear magnetic resonance technique is introduced for determination of both quadrupole and chemical/paramagnetic shift tensors and their relative orientation. The new method is based upon the well-known quadrupolar-echo experiment and is designed to refocus the quadrupolar interaction at the end of the t(1) evolution period while retaining the modulation introduced by the shift interaction. As a result, a projection of the resulting two-dimensional spectrum onto its F(1) dimension yields a shift anisotropy powder lineshape free from any quadrupolar broadening. The chemical/paramagnetic shifts appear in both F(1) and F(2) dimensions and are thus spread along a +1 frequency gradient; hence, a projection orthogonal to this gradient yields the pure quadrupolar powder lineshape, free from all shift interaction effects. The relative orientation of the quadrupole and shift tensors can be obtained by analysis of the full two-dimensional correlation lineshape. Unlike the well-known double-quantum experiment, the new method is, in principle, equally effective for all values of the quadrupolar splitting, including zero. The properties of the new technique are demonstrated using computer simulation and methods for the extraction of quadrupole and shift tensor parameters are described. The new technique is applied to (diamagnetic) benzoic acid-d(1) (C(6)H(5)CO(2)D) and (paramagnetic) copper(II) chloride dihydrate-d(4) (CuCl(2).2D(2)O). PMID:15740253

  14. Resonant Electromagnetic Interaction in Low Energy Nuclear Reactions

    NASA Astrophysics Data System (ADS)

    Chubb, Scott

    2008-03-01

    Basic ideas about how resonant electromagnetic interaction (EMI) can take place in finite solids are reviewed. These ideas not only provide a basis for conventional, electron energy band theory (which explains charge and heat transport in solids), but they also explain how through finite size effects, it is possible to create many of the kinds of effects envisioned by Giuliano Preparata. The underlying formalism predicts that the orientation of the external fields in the SPAWAR protocolootnotetextKrivit, Steven B., New Energy Times, 2007, issue 21, item 10. http://newenergytimes.com/news/2007/NET21.htm^,ootnotetextSzpak, S.; Mosier-Boss, P.A.; Gordon, F.E. Further evidence of nuclear reactions in the Pd lattice: emission of charged particles. Naturwissenschaften 94,511(2007)..has direct bearing on the emission of high-energy particles. Resonant EMI also implies that nano-scale solids, of a particular size, provide an optimal environment for initiating Low Energy Nuclear Reactions (LENR) in the PdD system.

  15. Rotating-frame gradient fields for magnetic resonance imaging and nuclear magnetic resonance in low fields

    DOEpatents

    Bouchard, Louis-Serge; Pines, Alexander; Demas, Vasiliki

    2014-01-21

    A system and method for Fourier encoding a nuclear magnetic resonance (NMR) signal is disclosed. A static magnetic field B.sub.0 is provided along a first direction. An NMR signal from the sample is Fourier encoded by applying a rotating-frame gradient field B.sub.G superimposed on the B.sub.0, where the B.sub.G comprises a vector component rotating in a plane perpendicular to the first direction at an angular frequency .omega.in a laboratory frame. The Fourier-encoded NMR signal is detected.

  16. Coherent nuclear resonant scattering by {sup 61}Ni using the nuclear lighthouse effect

    SciTech Connect

    Roth, T.; Leupold, O.; Wille, H.-C.; Rueffer, R.; Quast, K.W.; Burkel, E.; Roehlsberger, R.

    2005-04-01

    We have observed coherent nuclear resonant scattering of synchrotron radiation from the 67.41-keV level of {sup 61}Ni. The time evolution of the forward scattering signal was recorded by employing the nuclear lighthouse effect. This method is used to investigate Moessbauer isotopes in a coherent scattering process with synchrotron radiation at high transition energies. The decay of the excited ensemble of nuclei in Ni metal shows quantum beats that allowed the determination of the magnetic hyperfine field at the {sup 61}Ni nucleus. Moreover, we determined the lifetime of the 67.41-keV level of {sup 61}Ni to be 7.4(1) ns.

  17. First-principles theory of antishielding effects in the nuclear quadrupole interaction in ionic crystals: Application to 57mFe in Fe2O3

    NASA Astrophysics Data System (ADS)

    Beri, A. C.; Lee, Taesul; Das, T. P.; Sternheimer, R. M.

    1983-09-01

    A first-principles procedure is developed for the quantitative study of the widely differing Sternheimer antishielding effects that can be ascribed to the induced electric field gradients due to the various sources of electric field gradient in ionic crystals. The method involves the perturbation of the electronic states in the crystal by the nuclear quadrupole moment of the central ion, and the use of these perturbed functions in an evaluation of components of the energy of the crystal which are linear in the quadrupole moment. With each term in this energy, one can associate an induced field gradient due to a specific source in the crystal and a specific perturbation of the central-ion charge distribution. We have applied this ab initio method to a study of the nuclear quadrupole interaction for 57mFe in Fe2O3 using a model in which an Fe3+ ion is surrounded by six O2- ligands whose charge distributions overlap the Fe3+ ion. The application of our procedure to the model of overlapping ions leads to the important conclusion that the field gradients due to the various sources in the central cluster and the surrounding lattice are all subject to very different antishielding effects. The sources involved can be grouped broadly into three classes: local, nonlocal, and distant, with the local sources involving charge densities purely central in character, nonlocal sources involving charge densities composed of one central-ion orbital and one ligand-ion orbital, and the distant sources involving two categories, a distant electronic one composed of charge densities from purely ligand-ion orbitals, and a distant nuclear one, comprising the nuclear charges on the ligand ions (O2-). The effective antishielding factors γeff associated with these sources were found to be, respectively, -0.2, -0.7, -3.8, and -6.5, all very different from γ∞=-9.19 for the Fe3+ ion appropriate for a totally external point-charge source and R=+0.07, the shielding factor with the field

  18. The Fourier Transform in Chemistry. Part 1. Nuclear Magnetic Resonance: Introduction.

    ERIC Educational Resources Information Center

    King, Roy W.; Williams, Kathryn R.

    1989-01-01

    Using fourier transformation methods in nuclear magnetic resonance has made possible increased sensitivity in chemical analysis. This article describes these methods as they relate to magnetization, the RF magnetic field, nuclear relaxation, the RF pulse, and free induction decay. (CW)

  19. Investigating resonances above and below the threshold in nuclear reactions of astrophysical interest and beyond

    SciTech Connect

    La Cognata, M.; Kiss, G. G.; Mukhamedzhanov, A. M.; Spitaleri, C.; Trippella, O.

    2015-10-15

    Resonances in nuclear cross sections dramatically change their trends. Therefore, the presence of unexpected resonances might lead to unpredicted consequences on astrophysics and nuclear physics. In nuclear physics, resonances allow one to study states in the intermediate compound systems, to evaluate their cluster structure, for instance, especially in the energy regions approaching particle decay thresholds. In astrophysics, resonances might lead to changes in the nucleosynthesis flow, determining different isotopic compositions of the nuclear burning ashes. For these reasons, the Trojan Horse method has been modified to investigate resonant reactions. Thanks to this novel approach, for the first time normalization to direct data might be avoided. Moreover, in the case of sub threshold resonances, the Trojan Horse method modified to investigate resonances allows one to deduce the asymptotic normalization coefficient, showing the close connection between the two indirect approaches.

  20. Investigating resonances above and below the threshold in nuclear reactions of astrophysical interest and beyond

    NASA Astrophysics Data System (ADS)

    La Cognata, M.; Kiss, G. G.; Mukhamedzhanov, A. M.; Spitaleri, C.; Trippella, O.

    2015-10-01

    Resonances in nuclear cross sections dramatically change their trends. Therefore, the presence of unexpected resonances might lead to unpredicted consequences on astrophysics and nuclear physics. In nuclear physics, resonances allow one to study states in the intermediate compound systems, to evaluate their cluster structure, for instance, especially in the energy regions approaching particle decay thresholds. In astrophysics, resonances might lead to changes in the nucleosynthesis flow, determining different isotopic compositions of the nuclear burning ashes. For these reasons, the Trojan Horse method has been modified to investigate resonant reactions. Thanks to this novel approach, for the first time normalization to direct data might be avoided. Moreover, in the case of sub threshold resonances, the Trojan Horse method modified to investigate resonances allows one to deduce the asymptotic normalization coefficient, showing the close connection between the two indirect approaches.

  1. Simulations of nuclear resonance fluorescence in GEANT4

    NASA Astrophysics Data System (ADS)

    Lakshmanan, Manu N.; Harrawood, Brian P.; Rusev, Gencho; Agasthya, Greeshma A.; Kapadia, Anuj J.

    2014-11-01

    The nuclear resonance fluorescence (NRF) technique has been used effectively to identify isotopes based on their nuclear energy levels. Specific examples of its modern-day applications include detecting spent nuclear waste and cargo scanning for homeland security. The experimental designs for these NRF applications can be more efficiently optimized using Monte Carlo simulations before the experiment is implemented. One of the most widely used Monte Carlo physics simulations is the open-source toolkit GEANT4. However, NRF physics has not been incorporated into the GEANT4 simulation toolkit in publicly available software. Here we describe the development and testing of an NRF simulation in GEANT4. We describe in depth the development and architecture of this software for the simulation of NRF in any isotope in GEANT4; as well as verification and validation testing of the simulation for NRF in boron. In the verification testing, the simulation showed agreement with the analytical model to be within 0.6% difference for boron and iron. In the validation testing, the simulation showed agreement to be within 20.5% difference with the experimental measurements for boron, with the percent difference likely due to small uncertainties in beam polarization, energy distribution, and detector composition.

  2. Nucleon resonances and pion-nucleon interaction in nuclear matter above the [Delta] resonance energy

    SciTech Connect

    Arima, M. ); Masutani, K. ); Seki, R. Department of Physics, California State University, Northridge, California 91330 )

    1995-01-01

    We investigate the [pi]-nucleon interaction in nuclear matter around [radical][ital s] =1.5 GeV by examining dynamical modifications of [ital N][sup *] resonances microscopically. The pion production through the [pi][Delta] channel is suppressed appreciably in nuclear matter because the pion produced is strongly distorted through a [Delta] formation with a neighboring nucleon. This effect makes the width of [ital N](1520) smaller and the mass larger in nuclear medium than in free space, and the [pi][ital N] [ital D][sub 13]-wave amplitude loses much of its inelasticity. A similar situation arises with [ital N](1535) and the [pi][ital N] [ital S][sub 11]-wave amplitude because the [eta][ital N] channel is suppressed by Pauli blocking of the nucleus that accompanies [eta]. The total widths of [ital N][sup *] in nuclear medium, however, could be larger than in free space because of their spreading potentials.

  3. Nuclear Resonance Fluorescence off 54Cr: The Onset of the Pygmy Dipole Resonance

    NASA Astrophysics Data System (ADS)

    Ries, P. C.; Beck, T.; Beller, J.; Krishichayan; Gayer, U.; Isaak, J.; Löher, B.; Mertes, L.; Pai, H.; Pietralla, N.; Romig, C.; Savran, D.; Schilling, M.; Tornow, W.; Werner, V.; Zweidinger, M.

    2016-06-01

    Low-lying electric and magnetic dipole excitations (E1 and M1) below the neutron separation threshold, particularly the Pygmy Dipole Resonance (PDR), have drawn considerable attention in the last years. So far, mostly moderately heavy nuclei in the mass regions around A = 90 and A = 140 were examined with respect to the PDR. In the present work, the systematics of the PDR have been extended by measuring excitation strengths and parity quantum numbers of J = 1 states in lighter nuclei near A = 50 in order to gather information on the onset of the PDR. The nuclei 50,52,54Cr and 48,50Ti were examined via bremsstrahlung produced at the DArmstadt Superconducting electron Linear Accelerator (S-DALINAC) with photon energies up to 9.7 MeV with the method of nuclear resonance fluorescence. Numerous excited states were observed, many of which for the first time. The parity quantum numbers of these states have been determined at the High Intensity Gamma-ray Source (HIγS) of the Triangle Universities Nuclear Laboratory in Durham, NC, USA. Informations to the methods and the experimental setups will be provided and the results on 54Cr achieved will be discussed with respect to the onset of the PDR.

  4. Gradient elution capillary electrochromatography and hyphenation with nuclear magnetic resonance.

    PubMed

    Gfrörer, P; Schewitz, J; Pusecker, K; Tseng, L H; Albert, K; Bayer, E

    1999-01-01

    Coupling of gradient capillary electrochromatography (gradient CEC) and capillary zone electrophoresis (CZE) with nuclear magnetic resonance spectroscopy (NMR) was performed using a recently developed capillary NMR interface. This technique was applied for the analysis of pharmaceuticals and food. An analgesic was investigated using isocratic and gradient continuous-flow CEC-NMR. Comparison of the results demonstrated the superiority of gradient CEC over isocratic CEC. Aspartame and caffeine, both ingredients of soft beverages, were separated and analyzed by continuous flow CZE-NMR. The order of elution could be reversed by altering the pH. This reversal led to an increased sample concentration in the NMR detection cell, thus allowing the acquisition of a totally correlated spectroscopy (TOCSY) two-dimensional (2-D) spectrum of the synthetic peptide aspartame. PMID:10065951

  5. Quantitative velocity distributions via nuclear magnetic resonance flow metering

    NASA Astrophysics Data System (ADS)

    O'Neill, Keelan T.; Fridjonsson, Einar O.; Stanwix, Paul L.; Johns, Michael L.

    2016-08-01

    We demonstrate the use of Tikhonov regularisation as a data inversion technique to determine the velocity distributions of flowing liquid streams. Regularisation is applied to the signal produced by a nuclear magnetic resonance (NMR) flow measurement system consisting of a pre-polarising permanent magnet located upstream of an Earth's magnetic field NMR detection coil. A simple free induction decay (FID) NMR signal is measured for the flowing stream in what is effectively a 'time-of-flight' measurement. The FID signal is then modelled as a function of fluid velocity and acquisition time, enabling determination of the velocity probability distributions via regularisation. The mean values of these velocity distributions were successfully validated against in-line rotameters. The ability to quantify multi-modal velocity distributions was also demonstrated using a two-pipe system.

  6. Desktop fast-field cycling nuclear magnetic resonance relaxometer.

    PubMed

    Sousa, Duarte Mesquita; Marques, Gil Domingos; Cascais, José Manuel; Sebastião, Pedro José

    2010-07-01

    In this paper a new type of Fast Field Cycling (FFC) Nuclear Magnetic Resonance (NMR) relaxometer with low power consumption (200W) and cycle to cycle field stability better than 10(-4) is described. The new high-permeability magnet was designed to allow for good magnetic field homogeneity and allows for the sample rotation around an axis perpendicular to magnetic field, operating with magnetic fields between 0 and 0.21T. The power supply of the new relaxometer was specially developed in order to have steady state accurate currents and allow for magnetic field switching times less than 3ms. Additional control circuits were developed and included to compensate the Earth magnetic field component parallel to the field axis and to compensate for parasitic currents. The main aspects of the developed circuits together with some calibrating experimental results using the liquid crystal compounds 5CB and 8CB are presented and discussed.

  7. Bremsstrahlung from nuclear scattering at low energy near a resonance

    NASA Astrophysics Data System (ADS)

    Trail, C. C.; Lesser, P. M. S.; Liou, M. K.

    1984-04-01

    A program to contribute to the general understanding of nuclear reactions by determining as many of the off-shell properties of the proton-nucleus interaction as possible through the study of the proton-nucleus bremsstrahlung process is discussed. The limits of validity of a model independent analysis of these reactions in the neighborhood of a resonance or a breakup threshold are sought. The differences between this analysis and the data is utilized to elucidate those off-shell constraints which any valid proton-nucleus model interaction must satisfy. The bremsstrahlung process provides a method for determining the off-shell properties of the proton-nucleus potential, and the Brooklyn College program offers a unique opportunity to measure these crucial aspects of the low energy proton-nucleus interaction.

  8. Serum metabonomics of acute leukemia using nuclear magnetic resonance spectroscopy

    PubMed Central

    Musharraf, Syed Ghulam; Siddiqui, Amna Jabbar; Shamsi, Tahir; Choudhary, M. Iqbal; Rahman, Atta-ur

    2016-01-01

    Acute leukemia is a critical neoplasm of white blood cells. In order to differentiate between the metabolic alterations associated with two subtypes of acute leukemia, acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML), we investigated the serum of ALL and AML patients and compared with two controls (healthy and aplastic anemia) using 1H NMR (nuclear magnetic resonance) spectroscopy. Thirty-seven putative metabolites were identified using Carr-Purcell-Meiboom-Gill (CPMG) sequence. The use of PLS-DA and OPLS-DA models gave results with 84.38% and 90.63% classification rate, respectively. The metabolites responsible for classification are mainly lipids, lactate and glucose. Compared with controls, ALL and AML patients showed serum metabonomic differences involving aberrant metabolism pathways including glycolysis, TCA cycle, lipoprotein changes, choline and fatty acid metabolisms. PMID:27480133

  9. Nuclear magnetic resonance evaluation of stroke: a preliminary report

    SciTech Connect

    Bryan, R.N.; Willcott, M.R.; Schneiders, N.J.; Ford, J.J.; Derman, H.S.

    1983-10-01

    Nine patients who had acute and subacute stroke were examined by nuclear magnetic resonance (NMR) using a 6-MHz Bruker Instruments proton scanner. A modified Carr-Purcell-Meiboom-Gill pulse sequence was used for signal detection. The resultant string of spin-echoes was Fourier transformed into projections that were subsequently back-projected to a series of spin-echo images. From these images, spin density and T/sub 2/ were calculated for each pixel. The NMR scans revealed stroke in each of the patients, while CT demonstrated only eight of the lesions. T/sub 2/ was prolonged in all of the ischemic regions and is the most sensitive NMR parameter in detecting stroke. These preliminary results suggest that NMR scanning of patients who have acute stroke may be cliniclly useful, and that the T/sub 2/ component of the NRM signal is most important.

  10. Multipole-multimode Floquet theory in nuclear magnetic resonance.

    PubMed

    Ramachandran, Ramesh; Griffin, Robert G

    2005-04-22

    In this paper, we present a new analytical approach for describing the spin dynamics of synchronous and asynchronous time-dependent modulations in solid-state nuclear magnetic resonance experiments. The approach, based on multimode Floquet theory, employs the multipole operator basis of Sanctuary for spin description and illustrates the time evolution in the Floquet-Liouville space using the effective Hamiltonians obtained from the contact (or van Vleck) transformation procedure. Since the Hamiltonian and the density operator are expressed in terms of irreducible tensor operators, extensions to higher spin magnitudes (I>12) and multiple spins are quite straightforward and permit analytical treatments for many problems. We outline the general underlying principles involved in this approach with a brief mention of its potential application in other branches of spectroscopy. PMID:15945688

  11. Nuclear magnetic resonance spectral analysis and molecular properties of berberine

    NASA Astrophysics Data System (ADS)

    Huang, Ming-Ju; Lee, Ken S.; Hurley, Sharon J.

    An extensive theoretical study of berberine has been performed at the ab initio HF/6-31G**, HF/6-311G**, and B3LYP/6-311G** levels with and without solvent effects. The optimized structures are compared with X-ray data. We found that the optimized structures with solvent effects are in slightly better agreement with X-ray data than those without solvent effects. The 1H and 13C nuclear magnetic resonance (NMR) chemical shifts of berberine were calculated by using the gauge-independent atomic orbital (GIAO) (with and without solvent effects), CSGT, and IGAIM methods. The calculated chemical shifts were compared with the two-dimensional NMR experimental data. Overall, the calculated chemical shifts show very good agreement with the experimental results. The harmonic vibrational frequencies for berberine were calculated at the B3LYP/6-311G** level.

  12. Observation of superconductivity in hydrogen sulfide from nuclear resonant scattering.

    PubMed

    Troyan, Ivan; Gavriliuk, Alexander; Rüffer, Rudolf; Chumakov, Alexander; Mironovich, Anna; Lyubutin, Igor; Perekalin, Dmitry; Drozdov, Alexander P; Eremets, Mikhail I

    2016-03-18

    High-temperature superconductivity remains a focus of experimental and theoretical research. Hydrogen sulfide (H2S) has been reported to be superconducting at high pressures and with a high transition temperature. We report on the direct observation of the expulsion of the magnetic field in H2S compressed to 153 gigapascals. A thin (119)Sn film placed inside the H2S sample was used as a sensor of the magnetic field. The magnetic field on the (119)Sn sensor was monitored by nuclear resonance scattering of synchrotron radiation. Our results demonstrate that an external static magnetic field of about 0.7 tesla is expelled from the volume of (119)Sn foil as a result of the shielding by the H2S sample at temperatures between 4.7 K and approximately 140 K, revealing a superconducting state of H2S. PMID:26989248

  13. Phosphorus-31 nuclear magnetic resonance spectroscopy of toad retina.

    PubMed Central

    Apte, D V; Koutalos, Y; McFarlane, D K; Dawson, M J; Ebrey, T G

    1989-01-01

    Phosphorus-31 nuclear magnetic resonance (31P-NMR) spectra were obtained from living toad retinae and toad retinal extracts at 4 degrees C. Several phosphorus metabolites--nucleoside di- and triphosphates (NTP), phosphocreatine, phosphodiesters, inorganic phosphate, and phosphomonoesters--were identified from the spectra of whole retinae. The intracellular pH was determined to be 7.27 +/- 0.06 at 4 degrees C and the intracellular MgNTP/NTP ratio was at least 0.77. These results are consistent with those reported by other techniques, and they show that 31P-NMR spectroscopy can be used for noninvasively and quantitatively studying the metabolism of living toad retinae, and for monitoring its changes over time. PMID:2506940

  14. Nuclear resonance fluorescence imaging in non-intrusive cargo inspection

    NASA Astrophysics Data System (ADS)

    Bertozzi, William; Ledoux, Robert J.

    2005-12-01

    Nuclear resonance fluorescence is able to non-intrusively interrogate a region space and measure the isotopic content of the material in that space for any element with atomic number greater than that of helium. The technique involves exposing material to a continuous energy distribution of photons and detecting the scattered photons that have a discrete energy distribution unique to an isotope. The interrogating photons, which range from 2 to 8 MeV, are the most penetrating probes and can "see" through many inches of steel. Determination of the chemical components of the material occupying a region of space greatly enhances the identification of threats such as explosives, fissile materials, toxic materials and weapons of mass destruction. Systems can be designed to involve minimal operator intervention, to minimize dose to the sample, and to provide high throughput at commercial seaports, airports and other entry points.

  15. Quantitative velocity distributions via nuclear magnetic resonance flow metering.

    PubMed

    O'Neill, Keelan T; Fridjonsson, Einar O; Stanwix, Paul L; Johns, Michael L

    2016-08-01

    We demonstrate the use of Tikhonov regularisation as a data inversion technique to determine the velocity distributions of flowing liquid streams. Regularisation is applied to the signal produced by a nuclear magnetic resonance (NMR) flow measurement system consisting of a pre-polarising permanent magnet located upstream of an Earth's magnetic field NMR detection coil. A simple free induction decay (FID) NMR signal is measured for the flowing stream in what is effectively a 'time-of-flight' measurement. The FID signal is then modelled as a function of fluid velocity and acquisition time, enabling determination of the velocity probability distributions via regularisation. The mean values of these velocity distributions were successfully validated against in-line rotameters. The ability to quantify multi-modal velocity distributions was also demonstrated using a two-pipe system. PMID:27343484

  16. Gradient elution capillary electrochromatography and hyphenation with nuclear magnetic resonance.

    PubMed

    Gfrörer, P; Schewitz, J; Pusecker, K; Tseng, L H; Albert, K; Bayer, E

    1999-01-01

    Coupling of gradient capillary electrochromatography (gradient CEC) and capillary zone electrophoresis (CZE) with nuclear magnetic resonance spectroscopy (NMR) was performed using a recently developed capillary NMR interface. This technique was applied for the analysis of pharmaceuticals and food. An analgesic was investigated using isocratic and gradient continuous-flow CEC-NMR. Comparison of the results demonstrated the superiority of gradient CEC over isocratic CEC. Aspartame and caffeine, both ingredients of soft beverages, were separated and analyzed by continuous flow CZE-NMR. The order of elution could be reversed by altering the pH. This reversal led to an increased sample concentration in the NMR detection cell, thus allowing the acquisition of a totally correlated spectroscopy (TOCSY) two-dimensional (2-D) spectrum of the synthetic peptide aspartame.

  17. Applications of nuclear magnetic resonance imaging in process engineering

    NASA Astrophysics Data System (ADS)

    Gladden, Lynn F.; Alexander, Paul

    1996-03-01

    During the past decade, the application of nuclear magnetic resonance (NMR) imaging techniques to problems of relevance to the process industries has been identified. The particular strengths of NMR techniques are their ability to distinguish between different chemical species and to yield information simultaneously on the structure, concentration distribution and flow processes occurring within a given process unit. In this paper, examples of specific applications in the areas of materials and food processing, transport in reactors and two-phase flow are discussed. One specific study, that of the internal structure of a packed column, is considered in detail. This example is reported to illustrate the extent of new, quantitative information of generic importance to many processing operations that can be obtained using NMR imaging in combination with image analysis.

  18. Quantitative velocity distributions via nuclear magnetic resonance flow metering.

    PubMed

    O'Neill, Keelan T; Fridjonsson, Einar O; Stanwix, Paul L; Johns, Michael L

    2016-08-01

    We demonstrate the use of Tikhonov regularisation as a data inversion technique to determine the velocity distributions of flowing liquid streams. Regularisation is applied to the signal produced by a nuclear magnetic resonance (NMR) flow measurement system consisting of a pre-polarising permanent magnet located upstream of an Earth's magnetic field NMR detection coil. A simple free induction decay (FID) NMR signal is measured for the flowing stream in what is effectively a 'time-of-flight' measurement. The FID signal is then modelled as a function of fluid velocity and acquisition time, enabling determination of the velocity probability distributions via regularisation. The mean values of these velocity distributions were successfully validated against in-line rotameters. The ability to quantify multi-modal velocity distributions was also demonstrated using a two-pipe system.

  19. /sup 13/C nuclear magnetic resonance studies of cardiac metabolism

    SciTech Connect

    Seeholzer, S.H.

    1985-01-01

    The last decade has witnessed the increasing use of Nuclear Magnetic Resonance (NMR) techniques for following the metabolic fate of compounds specifically labeled with /sup 13/C. The goals of the present study are: (1) to develop reliable quantitative procedures for measuring the /sup 13/C enrichment of specific carbon sites in compounds enriched by the metabolism of /sup 13/C-labeled substrates in rat heart, and (2) to use these quantitative measurements of fractional /sup 13/C enrichment within the context of a mathematical flux model describing the carbon flow through the TCA cycle and ancillary pathways, as a means for obtaining unknown flux parameters. Rat hearts have been perfused in vitro with various combinations of glucose, acetate, pyruvate, and propionate to achieve steady state flux conditions, followed by perfusion with the same substrates labeled with /sup 13/C in specific carbon sites. The hearts were frozen at different times after addition of /sup 13/C-labeled substrates and neutralized perchloric acid extracts were used to obtain high resolution proton-decoupled /sup 13/C NMR spectra at 90.55 MHz. The fractional /sup 13/C enrichment (F.E.) of individual carbon sites in different metabolites was calculated from the area of the resolved resonances after correction for saturation and nuclear Overhauser effects. These F.E. measurements by /sup 13/C NMR were validated by the analysis of /sup 13/C-/sup 1/H scalar coupling patterns observed in /sup 1/H NMR spectra of the extracted metabolites. The results obtained from perfusion of hearts glucose plus either (2-/sup 13/C) acetate or (3-/sup 13/C) pyruvate are similar to those obtained by previous investigators using /sup 14/C-labeled substrates.

  20. Laser-induced nuclear magnetic resonance splitting in hydrocarbons.

    PubMed

    Ikäläinen, Suvi; Lantto, Perttu; Manninen, Pekka; Vaara, Juha

    2008-09-28

    Irradiation of matter with circularly polarized light (CPL) shifts all nuclear magnetic resonance (NMR) lines. The phenomenon arises from the second-order interaction of the electron cloud with the optical field, combined with the orbital hyperfine interaction. The shift occurs in opposite directions for right and left CPL, and rapid switching between them will split the resonance lines into two. We present ab initio and density functional theory predictions of laser-induced NMR splittings for hydrocarbon systems with different sizes: ethene, benzene, coronene, fullerene, and circumcoronene. Due to the computationally challenging nature of the effect, traditional basis sets could not be used for the larger systems. A novel method for generating basis sets, mathematical completeness optimization, was employed. As expected, the magnitude of the spectral splitting increases with the laser beam frequency and polarizability of the system. Massive amplification of the effect is also observed close to the optical excitation energies. A much larger laser-induced splitting is found for the largest of the present molecules than for the previously investigated noble gas atoms or small molecules. The laser intensity required for experimental detection of the effect is discussed.

  1. On the quantumness of correlations in nuclear magnetic resonance.

    PubMed

    Soares-Pinto, D O; Auccaise, R; Maziero, J; Gavini-Viana, A; Serra, R M; Céleri, L C

    2012-10-13

    Nuclear magnetic resonance (NMR) was successfully employed to test several protocols and ideas in quantum information science. In most of these implementations, the existence of entanglement was ruled out. This fact introduced concerns and questions about the quantum nature of such bench tests. In this paper, we address some issues related to the non-classical aspects of NMR systems. We discuss some experiments where the quantum aspects of this system are supported by quantum correlations of separable states. Such quantumness, beyond the entanglement-separability paradigm, is revealed via a departure between the quantum and the classical versions of information theory. In this scenario, the concept of quantum discord seems to play an important role. We also present an experimental implementation of an analogue of the single-photon Mach-Zehnder interferometer employing two nuclear spins to encode the interferometric paths. This experiment illustrates how non-classical correlations of separable states may be used to simulate quantum dynamics. The results obtained are completely equivalent to the optical scenario, where entanglement (between two field modes) may be present.

  2. Analysis of the transient response of nuclear spins in GaAs with/without nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Rasly, Mahmoud; Lin, Zhichao; Yamamoto, Masafumi; Uemura, Tetsuya

    2016-05-01

    As an alternative to studying the steady-state responses of nuclear spins in solid state systems, working within a transient-state framework can reveal interesting phenomena. The response of nuclear spins in GaAs to a changing magnetic field was analyzed based on the time evolution of nuclear spin temperature. Simulation results well reproduced our experimental results for the transient oblique Hanle signals observed in an all-electrical spin injection device. The analysis showed that the so called dynamic nuclear polarization can be treated as a cooling tool for the nuclear spins: It works as a provider to exchange spin angular momentum between polarized electron spins and nuclear spins through the hyperfine interaction, leading to an increase in the nuclear polarization. In addition, a time-delay of the nuclear spin temperature with a fast sweep of the external magnetic field produces a possible transient state for the nuclear spin polarization. On the other hand, the nuclear magnetic resonance acts as a heating tool for a nuclear spin system. This causes the nuclear spin temperature to jump to infinity: i.e., the average nuclear spins along with the nuclear field vanish at resonant fields of 75As, 69Ga and 71Ga, showing an interesting step-dip structure in the oblique Hanle signals. These analyses provide a quantitative understanding of nuclear spin dynamics in semiconductors for application in future computation processing.

  3. Molecular near-field antenna effect in resonance hyper-Raman scattering: Intermolecular vibronic intensity borrowing of solvent from solute through dipole-dipole and dipole-quadrupole interactions

    NASA Astrophysics Data System (ADS)

    Shimada, Rintaro; Hamaguchi, Hiro-o.

    2014-05-01

    We quantitatively interpret the recently discovered intriguing phenomenon related to resonance Hyper-Raman (HR) scattering. In resonance HR spectra of all-trans-β-carotene (β-carotene) in solution, vibrations of proximate solvent molecules are observed concomitantly with the solute β-carotene HR bands. It has been shown that these solvent bands are subject to marked intensity enhancements by more than 5 orders of magnitude under the presence of β-carotene. We have called this phenomenon the molecular-near field effect. Resonance HR spectra of β-carotene in benzene, deuterated benzene, cyclohexane, and deuterated cyclohexane have been measured precisely for a quantitative analysis of this effect. The assignments of the observed peaks are made by referring to the infrared, Raman, and HR spectra of neat solvents. It has been revealed that infrared active and some Raman active vibrations are active in the HR molecular near-field effect. The observed spectra in the form of difference spectra (between benzene/deuterated benzene and cyclohexane/deuterated cyclohexane) are quantitatively analyzed on the basis of the extended vibronic theory of resonance HR scattering. The theory incorporates the coupling of excited electronic states of β-carotene with the vibrations of a proximate solvent molecule through solute-solvent dipole-dipole and dipole-quadrupole interactions. It is shown that the infrared active modes arise from the dipole-dipole interaction, whereas Raman active modes from the dipole-quadrupole interaction. It is also shown that vibrations that give strongly polarized Raman bands are weak in the HR molecular near-field effect. The observed solvent HR spectra are simulated with the help of quantum chemical calculations for various orientations and distances of a solvent molecule with respect to the solute. The observed spectra are best simulated with random orientations of the solvent molecule at an intermolecular distance of 10 Å.

  4. Molecular near-field antenna effect in resonance hyper-Raman scattering: Intermolecular vibronic intensity borrowing of solvent from solute through dipole-dipole and dipole-quadrupole interactions

    SciTech Connect

    Shimada, Rintaro; Hamaguchi, Hiro-o

    2014-05-28

    We quantitatively interpret the recently discovered intriguing phenomenon related to resonance Hyper-Raman (HR) scattering. In resonance HR spectra of all-trans-β-carotene (β-carotene) in solution, vibrations of proximate solvent molecules are observed concomitantly with the solute β-carotene HR bands. It has been shown that these solvent bands are subject to marked intensity enhancements by more than 5 orders of magnitude under the presence of β-carotene. We have called this phenomenon the molecular-near field effect. Resonance HR spectra of β-carotene in benzene, deuterated benzene, cyclohexane, and deuterated cyclohexane have been measured precisely for a quantitative analysis of this effect. The assignments of the observed peaks are made by referring to the infrared, Raman, and HR spectra of neat solvents. It has been revealed that infrared active and some Raman active vibrations are active in the HR molecular near-field effect. The observed spectra in the form of difference spectra (between benzene/deuterated benzene and cyclohexane/deuterated cyclohexane) are quantitatively analyzed on the basis of the extended vibronic theory of resonance HR scattering. The theory incorporates the coupling of excited electronic states of β-carotene with the vibrations of a proximate solvent molecule through solute–solvent dipole–dipole and dipole–quadrupole interactions. It is shown that the infrared active modes arise from the dipole–dipole interaction, whereas Raman active modes from the dipole–quadrupole interaction. It is also shown that vibrations that give strongly polarized Raman bands are weak in the HR molecular near-field effect. The observed solvent HR spectra are simulated with the help of quantum chemical calculations for various orientations and distances of a solvent molecule with respect to the solute. The observed spectra are best simulated with random orientations of the solvent molecule at an intermolecular distance of 10 Å.

  5. Study of resonances in light nuclei for nuclear structure and nuclear astrophysics

    NASA Astrophysics Data System (ADS)

    Almaraz Calderon, Sergio Jesus

    Resonances in exotic nuclei play a central role in the nucleosynthesis processes occurring in the stars. Nuclear reactions proceed through resonance states in exotic nuclei. This dissertation reports on measurements of resonances in 18Ne, 30S and 9Be. The radioactive nucleus 18Ne was studied via the 16O(3He, n) reaction. These resonances are relevant in understanding one of the two breakout paths from the Hot Carbon-Oxygen-Nitrogen (HCNO) cycle. Neutrons from this reaction were measured in coincidence with charged particles from the decay of resonances in 18Ne to directly extract the charged particle branching ratios of the populated resonance states. Significant alpha branching ratios coming from the resonances at Eex = 7.95 MeV and Eex = 8.09 MeV were measured for the first time. Evidence of an exotic 2p decay is indicated from the state at Eex = 6.15 MeV. The results from this work allows for a more reliable calculation of the 14O( alpha, p)17F reaction rate, central in the breakout of the HCNO cycle and in the direct competition between alphap-process and the rp-process for the flow of nuclear material in the proton rich side of the valley of stability. The exotic nucleus 30S was studied via the 28 Si(3He, n) transfer reaction. Neutrons from this reaction were measured in coincidence with charged particle decays from the populated resonance states in 30S. Several states above Eex = 8.5 MeV are reported for the first time. For the states measured between the proton decay threshold and the alpha decay threshold, the branching ratios were extracted and used to tentatively assign spins and parities. The results led to the determination of the first experimental 26Si(alpha, p) 29P reaction rate. The calculated reaction rate is compared with statistical methods traditionally used in the calculations of such reaction rate. The results of the present work will be combined with the results of the 32S(p, t) experiment carried out by O'Brien. Resonance states with Isospin

  6. Cut and paste RNA for nuclear magnetic resonance, paramagnetic resonance enhancement, and electron paramagnetic resonance structural studies.

    PubMed

    Duss, Olivier; Diarra Dit Konté, Nana; Allain, Frédéric H-T

    2015-01-01

    RNA is a crucial regulator involved in most molecular processes of life. Understanding its function at the molecular level requires high-resolution structural information. However, the dynamic nature of RNA complicates structure determination because crystallization is often not possible or can result in crystal-packing artifacts resulting in nonnative structures. To study RNA and its complexes in solution, we described an approach in which large multi-domain RNA or protein-RNA complex structures can be determined at high resolution from isolated domains determined by nuclear magnetic resonance (NMR) spectroscopy, and then constructing the entire macromolecular structure using electron paramagnetic resonance (EPR) long-range distance constraints. Every step in this structure determination approach requires different types of isotope or spin-labeled RNAs. Here, we present a simple modular RNA cut and paste approach including protocols to generate (1) small isotopically labeled RNAs (<10 nucleotides) for NMR structural studies, which cannot be obtained by standard protocols, (2) large segmentally isotope and/or spin-labeled RNAs for diamagnetic NMR and paramagnetic relaxation enhancement NMR, and (3) large spin-labeled RNAs for pulse EPR spectroscopy.

  7. Nuclear magnetic resonance studies of macroscopic morphology and dynamics

    SciTech Connect

    Barrall, G A

    1995-09-01

    Nuclear magnetic resonance techniques are traditionally used to study molecular level structure and dynamics with a noted exception in medically applied NMR imaging (MRI). In this work, new experimental methods and theory are presented relevant to the study of macroscopic morphology and dynamics using NMR field gradient techniques and solid state two-dimensional exchange NMR. The goal in this work is not to take some particular system and study it in great detail, rather it is to show the utility of a number of new and novel techniques using ideal systems primarily as a proof of principle. By taking advantage of the analogy between NMR imaging and diffraction, one may simplify the experiments necessary for characterizing the statistical properties of the sample morphology. For a sample composed of many small features, e.g. a porous medium, the NMR diffraction techniques take advantage of both the narrow spatial range and spatial isotropy of the sample`s density autocorrelation function to obtain high resolution structural information in considerably less time than that required by conventional NMR imaging approaches. The time savings of the technique indicates that NMR diffraction is capable of finer spatial resolution than conventional NMR imaging techniques. Radio frequency NMR imaging with a coaxial resonator represents the first use of cylindrically symmetric field gradients in imaging. The apparatus as built has achieved resolution at the micron level for water samples, and has the potential to be very useful in the imaging of circularly symmetric systems. The study of displacement probability densities in flow through a random porous medium has revealed the presence of features related to the interconnectedness of the void volumes. The pulsed gradient techniques used have proven successful at measuring flow properties for time and length scales considerably shorter than those studied by more conventional techniques.

  8. Polaron hopping in olivine phosphates studied by nuclear resonant scattering

    NASA Astrophysics Data System (ADS)

    Tracy, Sally June

    Valence fluctuations of Fe2+ and Fe3+ were studied in a solid solution of LixFePO4 by nuclear resonant forward scattering of synchrotron x rays while the sample was heated in a diamond-anvil pressure cell. The spectra acquired at different temperatures and pressures were analyzed for the frequencies of valence changes using the Blume-Tjon model of a system with a fluctuating Hamiltonian. These frequencies were analyzed to obtain activation energies and an activation volume for polaron hopping. There was a large suppression of hopping frequency with pressure, giving an anomalously large activation volume. This large, positive value is typical of ion diffusion, which indicates correlated motions of polarons, and Li+ ions that alter the dynamics of both. In a parallel study of NaxFePO4, the interplay between sodium ordering and electron mobility was investigated using a combination of synchrotron x-ray diffraction and nuclear resonant scattering. Conventional Mossbauer spectra were collected while the sample was heated in a resistive furnace. An analysis of the temperature evolution of the spectral shapes was used to identify the onset of fast electron hopping and determine the polaron hopping rate. Synchrotron x-ray diffraction measurements were carried out in the same temperature range. Reitveld analysis of the diffraction patterns was used to determine the temperature of sodium redistribution on the lattice. The diffraction analysis also provides new information about the phase stability of the system. The temperature evolution of the iron site occupancies from the Mossbauer measurements, combined with the synchrotron diffraction results give strong evidence for a relationship between the onset of fast electron dynamics and the redistribution of sodium in the lattice. Measurements of activation barriers for polaron hopping gave fundamental insights about the correlation between electronic carriers and mobile ions. This work established that polaron-ion interactions

  9. Novel nuclear magnetic resonance techniques for studying biological molecules

    SciTech Connect

    Laws, David D.

    2000-06-01

    Over the fifty-five year history of Nuclear Magnetic Resonance (NMR), considerable progress has been made in the development of techniques for studying the structure, function, and dynamics of biological molecules. The majority of this research has involved the development of multi-dimensional NMR experiments for studying molecules in solution, although in recent years a number of groups have begun to explore NMR methods for studying biological systems in the solid-state. Despite this new effort, a need still exists for the development of techniques that improve sensitivity, maximize information, and take advantage of all the NMR interactions available in biological molecules. In this dissertation, a variety of novel NMR techniques for studying biomolecules are discussed. A method for determining backbone ({phi}/{psi}) dihedral angles by comparing experimentally determined {sup 13}C{sub a}, chemical-shift anisotropies with theoretical calculations is presented, along with a brief description of the theory behind chemical-shift computation in proteins and peptides. The utility of the Spin-Polarization Induced Nuclear Overhauser Effect (SPINOE) to selectively enhance NMR signals in solution is examined in a variety of systems, as are methods for extracting structural information from cross-relaxation rates that can be measured in SPINOE experiments. Techniques for the production of supercritical and liquid laser-polarized xenon are discussed, as well as the prospects for using optically pumped xenon as a polarizing solvent. In addition, a detailed study of the structure of PrP 89-143 is presented. PrP 89-143 is a 54 residue fragment of the prion proteins which, upon mutation and aggregation, can induce prion diseases in transgenic mice. Whereas the structure of the wild-type PrP 89-143 is a generally unstructured mixture of {alpha}-helical and {beta}-sheet conformers in the solid state, the aggregates formed from the PrP 89-143 mutants appear to be mostly {beta}-sheet.

  10. Two-dimensional nuclear magnetic resonance of quadrupolar systems

    SciTech Connect

    Wang, Shuanhu

    1997-09-17

    This dissertation describes two-dimensional nuclear magnetic resonance theory and experiments which have been developed to study quadruples in the solid state. The technique of multiple-quantum magic-angle spinning (MQMAS) is extensively reviewed and expanded upon in this thesis. Specifically, MQMAS is first compared with another technique, dynamic-angle spinning (DAS). The similarity between the two techniques allows us to extend much of the DAS work to the MQMAS case. Application of MQMAS to a series of aluminum containing materials is then presented. The superior resolution enhancement through MQMAS is exploited to detect the five- and six-coordinated aluminum in many aluminosilicate glasses. Combining the MQMAS method with other experiments, such as HETCOR, greatly expands the possibility of the use of MQMAS to study a large range of problems and is demonstrated in Chapter 5. Finally, the technique switching-angle spinning (SAS) is applied to quadrupolar nuclei to fully characterize a quadrupolar spin system in which all of the 8 NMR parameters are accurately determined. This dissertation is meant to demonstrate that with the combination of two-dimensional NMR concepts and new advanced spinning technologies, a series of multiple-dimensional NMR techniques can be designed to allow a detailed study of quadrupolar nuclei in the solid state.

  11. Updated methodology for nuclear magnetic resonance characterization of shales

    USGS Publications Warehouse

    Washburn, Kathryn E.; Birdwell, Justin E.

    2013-01-01

    Unconventional petroleum resources, particularly in shales, are expected to play an increasingly important role in the world’s energy portfolio in the coming years. Nuclear magnetic resonance (NMR), particularly at low-field, provides important information in the evaluation of shale resources. Most of the low-field NMR analyses performed on shale samples rely heavily on standard T1 and T2 measurements. We present a new approach using solid echoes in the measurement of T1 and T1–T2 correlations that addresses some of the challenges encountered when making NMR measurements on shale samples compared to conventional reservoir rocks. Combining these techniques with standard T1 and T2 measurements provides a more complete assessment of the hydrogen-bearing constituents (e.g., bitumen, kerogen, clay-bound water) in shale samples. These methods are applied to immature and pyrolyzed oil shale samples to examine the solid and highly viscous organic phases present during the petroleum generation process. The solid echo measurements produce additional signal in the oil shale samples compared to the standard methodologies, indicating the presence of components undergoing homonuclear dipolar coupling. The results presented here include the first low-field NMR measurements performed on kerogen as well as detailed NMR analysis of highly viscous thermally generated bitumen present in pyrolyzed oil shale.

  12. Nuclear magnetic resonance proton imaging of bone pathology

    SciTech Connect

    Atlan, H.; Sigal, R.; Hadar, H.; Chisin, R.; Cohen, I.; Lanir, A.; Soudry, M.; Machtey, Y.; Schreiber, R.; Benmair, J.

    1986-02-01

    Thirty-two patients with diversified pathology were examined with a supraconductive NMR imager using spin echo with different TR and TE to obtain T1 and T2 weighted images. They included 20 tumors (12 primary, eight metastasis), six osteomyelitis, three fractures, two osteonecrosis, and one diffuse metabolic (Gaucher) disease. In all cases except for the stress fractures, the bone pathology was clearly visualized in spite of the normal lack of signal from the compact cortical bone. Nuclear magnetic resonance (NMR) imaging proved to be at least as sensitive as radionuclide scintigraphy but much more accurate than all other imaging procedures including computed tomography (CT) and angiography to assess the extension of the lesions, especially in tumors extended to soft tissue. This is due both to easy acquisition of sagittal and coronal sections and to different patterns of pathologic modifications of T1 and T2 which are beginning to be defined. It is hoped that more experience in clinical use of these patterns will help to discriminate between tumor extension and soft-tissue edema. We conclude that while radionuclide scintigraphy will probably remain the most sensitive and easy to perform screening test for bone pathology, NMR imaging, among noninvasive diagnostic procedures, appears to be at least as specific as CT. In addition, where the extension of the lesions is concerned, NMR imaging is much more informative than CT. In pathology of the spine, the easy visualization of the spinal cord should decrease the need for myelography.

  13. Discrete decoding based ultrafast multidimensional nuclear magnetic resonance spectroscopy

    SciTech Connect

    Wei, Zhiliang; Lin, Liangjie; Ye, Qimiao; Li, Jing; Cai, Shuhui; Chen, Zhong

    2015-07-14

    The three-dimensional (3D) nuclear magnetic resonance (NMR) spectroscopy constitutes an important and powerful tool in analyzing chemical and biological systems. However, the abundant 3D information arrives at the expense of long acquisition times lasting hours or even days. Therefore, there has been a continuous interest in developing techniques to accelerate recordings of 3D NMR spectra, among which the ultrafast spatiotemporal encoding technique supplies impressive acquisition speed by compressing a multidimensional spectrum in a single scan. However, it tends to suffer from tradeoffs among spectral widths in different dimensions, which deteriorates in cases of NMR spectroscopy with more dimensions. In this study, the discrete decoding is proposed to liberate the ultrafast technique from tradeoffs among spectral widths in different dimensions by focusing decoding on signal-bearing sites. For verifying its feasibility and effectiveness, we utilized the method to generate two different types of 3D spectra. The proposed method is also applicable to cases with more than three dimensions, which, based on the experimental results, may widen applications of the ultrafast technique.

  14. Proton nuclear magnetic resonance studies on brain edema

    SciTech Connect

    Naruse, S.; Horikawa, Y.; Tanaka, C.; Hirakawa, K.; Nishikawa, H.; Yoshizaki, K.

    1982-06-01

    The water in normal and edematous brain tissues of rats was studied by the pulse nuclear magnetic resonance (NMR) technique, measuring the longitudinal relaxation time (T1) and the transverse relaxation time (T2). In the normal brain, T1 and T2 were single components, both shorter than in pure water. Prolongation and separation of T2 into two components, one fast and one slow, were the characteristic findings in brain edema induced by both cold injury and triethyl tin (TET), although some differences between the two types of edema existed in the content of the lesion and in the degree of changes in T1 and T2 values. Quantitative analysis of T1 and T2 values in their time course relating to water content demonstrated that prolongation of T1 referred to the volume of increased water in tissues examined, and that two phases of T2 reflected the distribution and the content of the edema fluid. From the analysis of the slow component of T2 versus water content during edema formation, it was demonstrated that the increase in edema fluid was steady, and its content was constant during formation of TET-induced edema. On the contrary, during the formation of cold-injury edema, water-rich edema fluid increased during the initial few hours, and protein-rich edema fluid increased thereafter. It was concluded that proton NMR relaxation time measurements may provide new understanding in the field of brain edema research.

  15. Monitoring iron mineralization processes using nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Keating, Kristina

    Proton nuclear magnetic resonance (NMR) measurements can be used to probe the molecular-scale physical and chemical environment of water in the pore space of geological materials. In geophysics, NMR relaxation measurements are used in to measure water content and estimate permeability in the top 100 m of Earth's surface. The goal of the research presented in this thesis is to determine if NMR can also be used in geophysical applications to monitor iron mineralization processes associated with contaminant remediation. The first part of the research presented in this thesis focuses on understanding the effect of iron mineral form and redox state on the NMR relaxation response of water in geologic material. Laboratory NMR measurements were made on Fe(III)-bearing minerals (ferrihydrite, lepidocrocite, goethite, and hematite), Fe(II)-bearing minerals (siderite, pyrite, and troilite), and a mixed valence iron-bearing mineral (magnetite). The results of these measurements show that the relaxation rate of water is strongly dependent on the mineral form of iron. Shown in the final section of this thesis are results from an experiment exploring temporal changes in the measured NMR relaxation rates during the reaction of ferrihydrite with aqueous Fe(II). These results show that NMR can be used to monitor temporal chemical changes in iron minerals. I conclude that this research shows that NMR indeed has the potential to be used as a tool for monitoring geochemical reactions associated with contaminant remediation.

  16. Water Permeability of Chlorella Cell Membranes by Nuclear Magnetic Resonance

    PubMed Central

    Stout, Darryl G.; Steponkus, Peter L.; Bustard, Larry D.; Cotts, Robert M.

    1978-01-01

    Measurement by two nuclear magnetic resonance (NMR) techniques of the mean residence time τa of water molecules inside Chlorella vulgaris (Beijerinck) var. “viridis” (Chodot) is reported. The first is the Conlon and Outhred (1972 Biochim Biophys Acta 288: 354-361) technique in which extracellular water is doped with paramagnetic Mn2+ ions. Some complications in application of this technique are identified as being caused by the affinity of Chlorella cell walls for Mn2+ ions which shortens the NMR relaxation times of intra- and extracellular water. The second is based upon observations of effects of diffusion on the spin echo of intra- and extracellular water. Echo attenuation of intracellular water is distinguished from that of extracellular water by the extent to which diffusive motion is restricted. Intracellular water, being restricted to the cell volume, suffers less echo attenuation. From the dependence of echo amplitude upon gradient strength at several values of echo time, the mean residence time of intracellular water can be determined. From the mean residence time of intracellular water, the diffusional water permeability coefficient of the Chlorella membrane is calculated to be 2.1 ± 0.4 × 10−3 cm sec−1. PMID:16660456

  17. TOPICAL REVIEW: Spatial localization in nuclear magnetic resonance spectroscopy

    NASA Astrophysics Data System (ADS)

    Keevil, Stephen F.

    2006-08-01

    The ability to select a discrete region within the body for signal acquisition is a fundamental requirement of in vivo NMR spectroscopy. Ideally, it should be possible to tailor the selected volume to coincide exactly with the lesion or tissue of interest, without loss of signal from within this volume or contamination with extraneous signals. Many techniques have been developed over the past 25 years employing a combination of RF coil properties, static magnetic field gradients and pulse sequence design in an attempt to meet these goals. This review presents a comprehensive survey of these techniques, their various advantages and disadvantages, and implications for clinical applications. Particular emphasis is placed on the reliability of the techniques in terms of signal loss, contamination and the effect of nuclear relaxation and J-coupling. The survey includes techniques based on RF coil and pulse design alone, those using static magnetic field gradients, and magnetic resonance spectroscopic imaging. Although there is an emphasis on techniques currently in widespread use (PRESS, STEAM, ISIS and MRSI), the review also includes earlier techniques, in order to provide historical context, and techniques that are promising for future use in clinical and biomedical applications.

  18. Stray-field nuclear magnetic resonance imaging in microgravity conditions

    NASA Astrophysics Data System (ADS)

    Garrido, Leoncio; Sampayo, José

    2008-03-01

    Magnetic levitation has been proposed as an alternative approach to simulate on Earth microgravity conditions encountered in space, allowing the investigation of weightlessness on materials and biological systems. In general, very strong magnetic fields, 15T or higher, are required to achieve levitation for a majority of diamagnetic substances. Here, we show that it is possible to achieve levitation of these substances in a commercial superconductive magnet operating with a nuclear magnetic resonance (NMR) spectrometer at 9.4T at ambient conditions. Furthermore, stray-field proton NMR imaging is performed in situ at the location where a sample is levitating, showing that it is feasible to obtain the corresponding one-dimensional profile. Considering that water is a diamagnetic substance and the main constituent of living systems, the outlined approach could be useful to investigate alterations in water proton NMR properties induced by low gravity and magnetic forces upon levitating, e.g., seeds, cells, etc. In addition to protons, it would also be possible to observe other nuclei (e.g., F19, P31, etc.) that may be of interest in metabolic and therapeutic investigations.

  19. Advances in Nuclear Magnetic Resonance for Drug Discovery.

    PubMed

    Powers, Robert

    2009-10-01

    BACKGROUND: Drug discovery is a complex and unpredictable endeavor with a high failure rate. Current trends in the pharmaceutical industry have exasperated these challenges and are contributing to the dramatic decline in productivity observed over the last decade. The industrialization of science by forcing the drug discovery process to adhere to assembly-line protocols is imposing unnecessary restrictions, such as short project time-lines. Recent advances in nuclear magnetic resonance are responding to these self-imposed limitations and are providing opportunities to increase the success rate of drug discovery. OBJECTIVE/METHOD: A review of recent advancements in NMR technology that have the potential of significantly impacting and benefiting the drug discovery process will be presented. These include fast NMR data collection protocols and high-throughput protein structure determination, rapid protein-ligand co-structure determination, lead discovery using fragment-based NMR affinity screens, NMR metabolomics to monitor in vivo efficacy and toxicity for lead compounds, and the identification of new therapeutic targets through the functional annotation of proteins by FAST-NMR. CONCLUSION: NMR is a critical component of the drug discovery process, where the versatility of the technique enables it to continually expand and evolve its role. NMR is expected to maintain this growth over the next decade with advancements in automation, speed of structure calculation, in-cell imaging techniques, and the expansion of NMR amenable targets.

  20. Nuclear magnetic resonance studies of bovine γB-crystallin

    NASA Astrophysics Data System (ADS)

    Thurston, George; Mills, Jeffrey; Michel, Lea; Mathews, Kaylee; Zanet, John; Payan, Angel; van Nostrand, Keith; Kotlarchyk, Michael; Ross, David; Wahle, Christopher; Hamilton, John

    Anisotropy of shape and/or interactions play an important role in determining the properties of concentrated solutions of the eye lens protein, γB-crystallin, including its liquid-liquid phase transition. We are studying γB anisotropic interactions with use of nuclear magnetic resonance (NMR) concentration- and temperature-dependent chemical shift perturbations (CSPs). We analyze two-dimensional heteronuclear spin quantum coherence (HSQC) spectra on backbone nitrogen and attached hydrogen nuclei for CSPs, up to 3 percent volume fraction. Cumulative distribution functions of the CSPs show a concentration and temperature-dependent spread. Many peaks that are highly shifted with either concentration or temperature are close (i) crystal intermolecular contacts (ii) locations of cataractogenic point mutations of a homologous human protein, human γD-crystallin, and (iii) charged amino-acid residues. We also discuss the concentration- and temperature-dependence of NMR and quasielastic light scattering measurements of rotational and translational diffusion of γB crystallin in solution, affected by interprotein attractions. Supported by NIH EY018249.

  1. Nuclear magnetic resonance imaging of the kidney: renal masses

    SciTech Connect

    Hricak, H.; Williams, R.D.; Moon, K.L. Jr.; Moss, A.A.; Alpers, C.; Crooks, L.E.; Kaufman, L.

    1983-06-01

    Fifteen patients with a variety of renal masses were examined by nuclear magnetic resonance (NMR), computed tomography, ultrasound, and intravenous urography. NMR clearly differentiated between simple renal cysts and other renal masses. On spin echo images, the simple renal cyst appeared as a round or slightly oval, homogeneous low-intensity mass with characteristically long T1 and T2 values. The thickness of the cyst wall was not measurable. The cyst had a smooth outer margin and a distict, sharp interface with normal parenchyma. Hemorrhagic cysts were seen as high-intensity lesions. Renal cell carcinomas displayed a wide range of intensity. The T1 and T2 values of the tumors were always different from those of the surrounding renal parenchyma. Tumor pseudocapsule was identified in four of five patients examined. All carcinomas were accurately staged by NMR and extension of the tumor thrombus into the inferior vena cava was demonstrated. The authors predict that if these preliminary results are confirmed by data from a larger number of patients, NMR will play a significant role in renal imaging.

  2. Spherical tensor analysis of nuclear magnetic resonance signals.

    PubMed

    van Beek, Jacco D; Carravetta, Marina; Antonioli, Gian Carlo; Levitt, Malcolm H

    2005-06-22

    In a nuclear magnetic-resonance (NMR) experiment, the spin density operator may be regarded as a superposition of irreducible spherical tensor operators. Each of these spin operators evolves during the NMR experiment and may give rise to an NMR signal at a later time. The NMR signal at the end of a pulse sequence may, therefore, be regarded as a superposition of spherical components, each derived from a different spherical tensor operator. We describe an experimental method, called spherical tensor analysis (STA), which allows the complete resolution of the NMR signal into its individual spherical components. The method is demonstrated on a powder of a (13)C-labeled amino acid, exposed to a pulse sequence generating a double-quantum effective Hamiltonian. The propagation of spin order through the space of spherical tensor operators is revealed by the STA procedure, both in static and rotating solids. Possible applications of STA to the NMR of liquids, liquid crystals, and solids are discussed. PMID:16035785

  3. Nuclear magnetic resonance imaging of water content in the subsurface

    SciTech Connect

    J. Hendricks; T. Yao; A. Kearns

    1999-01-21

    Previous theoretical and experimental studies indicated that surface nuclear magnetic resonance (NMR) has the potential to provide cost-effective water content measurements in the subsurface and is a technology ripe for exploitation in practice. The objectives of this investigation are (a) to test the technique under a wide range of hydrogeological conditions and (b) to generalize existing NMR theories in order to correctly model NMR response from conductive ground and to assess properties of the inverse problem. Twenty-four sites with different hydrogeologic settings were selected in New Mexico and Colorado for testing. The greatest limitation of surface NMR technology appears to be the lack of understanding in which manner the NMR signal is influenced by soil-water factors such as pore size distribution, surface-to-volume ratio, paramagnetic ions dissolved in the ground water, and the presence of ferromagnetic minerals. Although the theoretical basis is found to be sound, several advances need to be made to make surface NMR a viable technology for hydrological investigations. There is a research need to investigate, under controlled laboratory conditions, how the complex factors of soil-water systems affect NMR relaxation times.

  4. A nuclear magnetic resonance study of water in aggrecan solutions

    PubMed Central

    Foster, Richard J.; Damion, Robin A.; Baboolal, Thomas G.; Smye, Stephen W.; Ries, Michael E.

    2016-01-01

    Aggrecan, a highly charged macromolecule found in articular cartilage, was investigated in aqueous salt solutions with proton nuclear magnetic resonance. The longitudinal and transverse relaxation rates were determined at two different field strengths, 9.4 T and 0.5 T, for a range of temperatures and aggrecan concentrations. The diffusion coefficients of the water molecules were also measured as a function of temperature and aggrecan concentration, using a pulsed field gradient technique at 9.4 T. Assuming an Arrhenius relationship, the activation energies for the various relaxation processes and the translational motion of the water molecules were determined from temperature dependencies as a function of aggrecan concentration in the range 0–5.3% w/w. The longitudinal relaxation rate and inverse diffusion coefficient were approximately equally dependent on concentration and only increased by upto 20% from that of the salt solution. The transverse relaxation rate at high field demonstrated greatest concentration dependence, changing by an order of magnitude across the concentration range examined. We attribute this primarily to chemical exchange. Activation energies appeared to be approximately independent of aggrecan concentration, except for that of the low-field transverse relaxation rate, which decreased with concentration. PMID:27069663

  5. Discrete decoding based ultrafast multidimensional nuclear magnetic resonance spectroscopy

    NASA Astrophysics Data System (ADS)

    Wei, Zhiliang; Lin, Liangjie; Ye, Qimiao; Li, Jing; Cai, Shuhui; Chen, Zhong

    2015-07-01

    The three-dimensional (3D) nuclear magnetic resonance (NMR) spectroscopy constitutes an important and powerful tool in analyzing chemical and biological systems. However, the abundant 3D information arrives at the expense of long acquisition times lasting hours or even days. Therefore, there has been a continuous interest in developing techniques to accelerate recordings of 3D NMR spectra, among which the ultrafast spatiotemporal encoding technique supplies impressive acquisition speed by compressing a multidimensional spectrum in a single scan. However, it tends to suffer from tradeoffs among spectral widths in different dimensions, which deteriorates in cases of NMR spectroscopy with more dimensions. In this study, the discrete decoding is proposed to liberate the ultrafast technique from tradeoffs among spectral widths in different dimensions by focusing decoding on signal-bearing sites. For verifying its feasibility and effectiveness, we utilized the method to generate two different types of 3D spectra. The proposed method is also applicable to cases with more than three dimensions, which, based on the experimental results, may widen applications of the ultrafast technique.

  6. Work in progress: nuclear magnetic resonance imaging of the gallbladder

    SciTech Connect

    Hricak, H.; Filly, R.A.; Margulis, A.R.; Moon, K.L.; Crooks, L.E.; Kaufman, L.

    1983-05-01

    A preliminary study of the relation between food intake and intensity of gallbladder bile on nuclear magnetic resonance (NMR) images was made. Twelve subjects (seven volunteers, five patients) were imaged following a minimum of 14 hours of fasting. Six of seven volunteers were reimaged one hour after stimulation by either a fatty meal or an alcoholic beverage. An additional seven patients were imaged two hours after a hospital breakfast. It was found that concentrated bile emits a high-intensity spin echo signal (SE), while hepatic bile in the gallbladder produces a low-intensity SE signal. Following ingestion of cholecystogogue, dilute hepatic bile settles on top of the concentrated bile, each emitting SE signals of different intensity. The average T1 value of concentrated bile was 594 msec, while the T1 vaue of dilute hepatic bile was 2,646 msec. The average T2 values were 104 msec for concentrated bile and 126 msec for dilute bile. The most likely cause for the different SE intensities of bile is the higher water content, and therefore longer T1 or T2 relaxation times, of hepatic bile. It is suggested that NMR imaging has the ability to provide physiological information about the gallbladder and that it may prove to be a simple and safe clinical test of gallbladder function.

  7. Advances in Nuclear Magnetic Resonance for Drug Discovery

    PubMed Central

    Powers, Robert

    2010-01-01

    Background Drug discovery is a complex and unpredictable endeavor with a high failure rate. Current trends in the pharmaceutical industry have exasperated these challenges and are contributing to the dramatic decline in productivity observed over the last decade. The industrialization of science by forcing the drug discovery process to adhere to assembly-line protocols is imposing unnecessary restrictions, such as short project time-lines. Recent advances in nuclear magnetic resonance are responding to these self-imposed limitations and are providing opportunities to increase the success rate of drug discovery. Objective/Method A review of recent advancements in NMR technology that have the potential of significantly impacting and benefiting the drug discovery process will be presented. These include fast NMR data collection protocols and high-throughput protein structure determination, rapid protein-ligand co-structure determination, lead discovery using fragment-based NMR affinity screens, NMR metabolomics to monitor in vivo efficacy and toxicity for lead compounds, and the identification of new therapeutic targets through the functional annotation of proteins by FAST-NMR. Conclusion NMR is a critical component of the drug discovery process, where the versatility of the technique enables it to continually expand and evolve its role. NMR is expected to maintain this growth over the next decade with advancements in automation, speed of structure calculation, in-cell imaging techniques, and the expansion of NMR amenable targets. PMID:20333269

  8. Nuclear resonance tomography with a toroid cavity detector

    DOEpatents

    Woelk, K.; Rathke, J.W.; Klingler, R.J.

    1996-11-12

    A toroid cavity detection system is described for determining the spectral properties and distance from a fixed point for a sample using Nuclear Magnetic Resonance. The detection system consists of a toroid with a central conductor oriented along the main axis of the toroidal cylinder and perpendicular to a static uniform magnetic field oriented along the main axis of the toroid. An rf signal is input to the central conductor to produce a magnetic field perpendicular to the central axis of the toroid and whose field strength varies as the inverse of the radius of the toroid. The toroid cavity detection system can be used to encapsulate a sample, or the detection system can be perforated to allow a sample to flow into the detection device or to place the samples in specified sample tubes. The central conductor can also be coated to determine the spectral property of the coating and the coating thickness. The sample is then subjected to the respective magnetic fields and the responses measured to determine the desired properties. 4 figs.

  9. A metabonomics investigation of multiple sclerosis by nuclear magnetic resonance.

    PubMed

    Mehrpour, Masoud; Kyani, Anahita; Tafazzoli, Mohsen; Fathi, Fariba; Joghataie, Mohammad-Taghi

    2013-02-01

    Multiple sclerosis (MS) is a nervous system disease that affects the fatty myelin sheaths around the axons of the brain and spinal cord, leading to demyelination and a broad range of signs and symptoms. MS can be difficult to diagnose because its signs and symptoms may be similar to other medical problems. To find out which metabolites in serum are effective for the diagnosis of MS, we utilized metabolic profiling using proton nuclear magnetic resonance spectroscopy ((1)H-NMR). Random forest (RF) was used to classify the MS patients and healthy subjects. Atomic absorption spectroscopy was used to measure the serum levels of selenium. The results showed that the levels of selenium were lower in the MS group, when compared with the control group. RF was used to identify the metabolites that caused selenium changes in people with MS by building a correlation model between these metabolites and serum levels of selenium. For the external test set, the obtained classification model showed a 93% correct classification of MS and healthy subjects. The regression model of levels of selenium and metabolites showed the correlation (R(2)) value of 0.88 for the external test set. The results indicate the suitability of NMR as a screen for identifying MS patients and healthy subjects. A novel model with good prediction outcomes was constructed between serum levels of selenium and NMR data. PMID:23255426

  10. Nuclear resonance tomography with a toroid cavity detector

    DOEpatents

    Woelk, Klaus; Rathke, Jerome W.; Klingler, Robert J.

    1996-01-01

    A toroid cavity detection system for determining the spectral properties and distance from a fixed point for a sample using Nuclear Magnetic Resonance. The detection system consists of a toroid with a central conductor oriented along the main axis of the toroidal cylinder and perpendicular to a static uniform magnetic field oriented along the main axis of the toroid. An rf signal is inputted to the central conductor to produce a magnetic field perpendicular to the central axis of the toroid and whose field strength varies as the inverse of the radius of the toroid. The toroid cavity detection system can be used to encapsulate a sample, or the detection system can be perforated to allow a sample to flow into the detection device or to place the samples in specified sample tubes. The central conductor can also be coated to determine the spectral property of the coating and the coating thickness. The sample is then subjected to the respective magnetic fields and the responses measured to determine the desired properties.

  11. MEMS-Based Force-Detected Nuclear Magnetic Resonance (FDNMR) Spectrometer

    NASA Technical Reports Server (NTRS)

    Lee, Choonsup; Butler, Mark C.; Elgammal, Ramez A.; George, Thomas; Hunt, Brian; Weitekamp, Daniel P.

    2006-01-01

    Nuclear Magnetic Resonance (NMR) spectroscopy allows assignment of molecular structure by acquiring the energy spectrum of nuclear spins in a molecule, and by interpreting the symmetry and positions of resonance lines in the spectrum. As such, NMR has become one of the most versatile and ubiquitous spectroscopic methods. Despite these tremendous successes, NMR experiments suffer from inherent low sensitivity due to the relatively low energy of photons in the radio frequency (rt) region of the electromagnetic spectrum. Here, we describe a high-resolution spectroscopy in samples with diameters in the micron range and below. We have reported design and fabrication of force-detected nuclear magnetic resonance (FDNMR).

  12. Development of a micro nuclear magnetic resonance system

    NASA Astrophysics Data System (ADS)

    Goloshevsky, Artem

    Application of Nuclear Magnetic Resonance (NMR) to on-line/in-line control of industrial processes is currently limited by equipment costs and requirements for installation. A superconducting magnet generating strong fields is the most expensive part of a typical NMR instrument. In industrial environments, fringe magnetic fields make accommodation of NMR instruments difficult. However, a portable, low-cost and low-field magnetic resonance system can be used in virtually any environment. Development of a number of hardware components for a portable, low-cost NMR instrument is reported in this dissertation. Chapter one provides a discussion on a miniaturized Helmholtz spiral radio-frequency (RF) coil (average diameter equal to 3.5 mm) and an NMR probe built around a capillary (outer diameter = 1.59 mm and inner diameter = 1.02 mm) for flow imaging. Experiments of NMR spectroscopy, static and dynamic (flow) imaging, conducted with the use of the miniaturized coil, are described. Chapter two presents a microfabricated package of two biaxial gradient coils and a Helmholtz RF coil. Planar configuration of discrete wires was used to create magnetic field gradients. Performance of the microfabricated gradient coils while imaging water flow compared well with a commercial gradient set of much larger size. Chapter three reports on flow imaging experiments with power law fluids (aqueous solutions of sodium salt of carboxymethyl cellulose (CMC)) of different viscosities, carried out in the NMR probe with the miniaturized RF coil and capillary. Viscosities of the CMC solutions were determined based on the curve fits of the velocity profiles and simultaneous measurements of the flow rates. The curve fits were carried out according to the power law model equations. The NMR viscosity measurements compared well with measurements of the same CMC samples, performed on a conventional rotational rheometer. A portable, home-built transceiver, designed for NMR applications utilizing a

  13. [Progress in nuclear magnetic resonance spectroscopy for early cancer diagnosis].

    PubMed

    Gao, Xiu-xiang; Xu, Yi-zhuang; Zhao, Mei-xian; Qi, Jian; Li, Hui-zhen; Wu, Jin-guang

    2008-08-01

    Based on more than 100 references, the present paper reviews the progress in the application of nuclear magnetic resonance (NMR) spectroscopy, an effective method to study the variation in chemical composition and molecular structure in biological samples for early diagnosis of cancer at molecular level. In the past several decades, numerous works have demonstrated that NMR spectroscopy may be developed into a sensitive diagnosis method to detect cancer in early stage. Because of the rapid development of NMR spectroscopic techniques, it becomes possible to record NMR spectra of biological samples in both in-vitro and in-vivo manner. Systematic spectral differences between biological samples from cancer patients and normal controls can be observed from both liquid-state and solid-state 1H, 31P NMR spectra and used to reflect the changes in metabolic behavior of malignant tissues. This paper has summarized NMR spectroscopic investigation on biological fluid, cultured cancerous cells, resected tissues, as well as in-vivo malignant tissues by using various advanced NMR techniques including recently developedhigh-resolution magic angle spinning (HR-MAS)and magnetic resonance spectroscopy and imaging (MRSI) methods. First, characteristic peaks, which are related to choline, phosphocholine (PC) and glycerophosphocholine, can be observed in both 1H and 31P NMR spectra of biological fluid samples from cancer patients. These results indicate that alternation in the metabolic pattern occurs with the progression of cancer. The research on cultured cells by using NMR spectroscopy showed that the signal of various phospholipids and their metabolites such as PME increased significantly in cultured cancer cells. For resected tissues, two methods can be utilized. The first one is to investigate the tissues directly by using HR-MAS spectroscopy. The second method is to extract various metabolites with various solvents such as CHCl3/methonal mixtures, HClO4 solutions, etc. and then

  14. Study of the extra-ionic electron distributions in semi-metallic structures by nuclear quadrupole resonance techniques

    NASA Technical Reports Server (NTRS)

    Murty, A. N.

    1976-01-01

    A straightforward self-consistent method was developed to estimate solid state electrostatic potentials, fields and field gradients in ionic solids. The method is a direct practical application of basic electrostatics to solid state and also helps in the understanding of the principles of crystal structure. The necessary mathematical equations, derived from first principles, were presented and the systematic computational procedure developed to arrive at the solid state electrostatic field gradients values was given.

  15. A Multidisciplinary Approach to High Throughput Nuclear Magnetic Resonance Spectroscopy

    PubMed Central

    Pourmodheji, Hossein; Ghafar-Zadeh, Ebrahim; Magierowski, Sebastian

    2016-01-01

    Nuclear Magnetic Resonance (NMR) is a non-contact, powerful structure-elucidation technique for biochemical analysis. NMR spectroscopy is used extensively in a variety of life science applications including drug discovery. However, existing NMR technology is limited in that it cannot run a large number of experiments simultaneously in one unit. Recent advances in micro-fabrication technologies have attracted the attention of researchers to overcome these limitations and significantly accelerate the drug discovery process by developing the next generation of high-throughput NMR spectrometers using Complementary Metal Oxide Semiconductor (CMOS). In this paper, we examine this paradigm shift and explore new design strategies for the development of the next generation of high-throughput NMR spectrometers using CMOS technology. A CMOS NMR system consists of an array of high sensitivity micro-coils integrated with interfacing radio-frequency circuits on the same chip. Herein, we first discuss the key challenges and recent advances in the field of CMOS NMR technology, and then a new design strategy is put forward for the design and implementation of highly sensitive and high-throughput CMOS NMR spectrometers. We thereafter discuss the functionality and applicability of the proposed techniques by demonstrating the results. For microelectronic researchers starting to work in the field of CMOS NMR technology, this paper serves as a tutorial with comprehensive review of state-of-the-art technologies and their performance levels. Based on these levels, the CMOS NMR approach offers unique advantages for high resolution, time-sensitive and high-throughput bimolecular analysis required in a variety of life science applications including drug discovery. PMID:27294925

  16. A Multidisciplinary Approach to High Throughput Nuclear Magnetic Resonance Spectroscopy.

    PubMed

    Pourmodheji, Hossein; Ghafar-Zadeh, Ebrahim; Magierowski, Sebastian

    2016-06-09

    Nuclear Magnetic Resonance (NMR) is a non-contact, powerful structure-elucidation technique for biochemical analysis. NMR spectroscopy is used extensively in a variety of life science applications including drug discovery. However, existing NMR technology is limited in that it cannot run a large number of experiments simultaneously in one unit. Recent advances in micro-fabrication technologies have attracted the attention of researchers to overcome these limitations and significantly accelerate the drug discovery process by developing the next generation of high-throughput NMR spectrometers using Complementary Metal Oxide Semiconductor (CMOS). In this paper, we examine this paradigm shift and explore new design strategies for the development of the next generation of high-throughput NMR spectrometers using CMOS technology. A CMOS NMR system consists of an array of high sensitivity micro-coils integrated with interfacing radio-frequency circuits on the same chip. Herein, we first discuss the key challenges and recent advances in the field of CMOS NMR technology, and then a new design strategy is put forward for the design and implementation of highly sensitive and high-throughput CMOS NMR spectrometers. We thereafter discuss the functionality and applicability of the proposed techniques by demonstrating the results. For microelectronic researchers starting to work in the field of CMOS NMR technology, this paper serves as a tutorial with comprehensive review of state-of-the-art technologies and their performance levels. Based on these levels, the CMOS NMR approach offers unique advantages for high resolution, time-sensitive and high-throughput bimolecular analysis required in a variety of life science applications including drug discovery.

  17. Advances in Theory of Solid-State Nuclear Magnetic Resonance

    PubMed Central

    Mananga, Eugene S.; Moghaddasi, Jalil; Sana, Ajaz; Akinmoladun, Andrew; Sadoqi, Mostafa

    2015-01-01

    Recent advances in theory of solid state nuclear magnetic resonance (NMR) such as Floquet-Magnus expansion and Fer expansion, address alternative methods for solving a time-dependent linear differential equation which is a central problem in quantum physics in general and solid-state NMR in particular. The power and the salient features of these theoretical approaches that are helpful to describe the time evolution of the spin system at all times are presented. This review article presents a broad view of manipulations of spin systems in solid-state NMR, based on milestones theories including the average Hamiltonian theory and the Floquet theory, and the approaches currently developing such as the Floquet-Magnus expansion and the Fer expansion. All these approaches provide procedures to control and describe the spin dynamics in solid-state NMR. Applications of these theoretical methods to stroboscopic and synchronized manipulations, non-synchronized experiments, multiple incommensurated frequencies, magic-angle spinning samples, are illustrated. We also reviewed the propagators of these theories and discussed their convergences. Note that the FME is an extension of the popular Magnus Expansion and Average Hamiltonian Theory. It aims is to bridge the AHT to the Floquet Theorem but in a more concise and efficient formalism. Calculations can then be performed in a finite-dimensional Hilbert space instead of an infinite dimensional space within the so-called Floquet theory. We expected that the FME will provide means for more accurate and efficient spin dynamics simulation and for devising new RF pulse sequence. PMID:26878063

  18. Predicting Nuclear Resonance Vibrational Spectra of [Fe(OEP)(NO)].

    PubMed

    Peng, Qian; Pavlik, Jeffrey W; Scheidt, W Robert; Wiest, Olaf

    2012-01-10

    Nuclear Resonance Vibrational Spectroscopy (NRVS) is a sensitive vibrational probe for biologically important heme complexes. The exquisite sensitivity of the NRVS data to the electronic structure provides detailed insights into the nature of these interesting compounds, but requires highly accurate computational methods for the mode assignments. To determine the best combinations of density functionals and basis sets, a series of benchmark DFT calculations on the previously characterized complex [Fe(OEP)NO] (OEP(2-)=octaethylporphyrinatio dianion) were performed. A test set of 21 methodology combinations including 8 functionals (BP86, mPWPW91, B3LYP, PBE1PBE, M062X, M06L, LC-BP86 and ωB97X-D) and 5 basis set (VTZ, TZVP, Lanl2DZ for iron and 6-31G*, 6-31+G* for other atoms) was carried out to calculate electronic structures and vibrational frequencies. We also implemented the conversion of frequency calculations into orientation-selective mode composition factors (e(2)), which can used to simulate the Vibrational Density Of States (VDOS) using Gaussian normal distribution functions. These use a series of user-friendly scripts for their application to NRVS. The structures as well as the isotropic and anisotropic NRVS of [Fe(OEP)NO] obtained with the M06L functional with a variety of basis sets are found to best reproduce the available experimental data, followed by B3LYP/LanL2DZ calculations. Other density functionals and basis sets do not produce the same level of accuracy. The noticeably worse agreement between theory and experiment for the out-plane NRVS compared with the excellent performance of the M06L functional for the in-plane prediction is attributed to deficiencies of the physical model rather than the computational methodology. PMID:23204948

  19. Novel detection schemes of nuclear magnetic resonance and magnetic resonance imaging: applications from analytical chemistry to molecular sensors.

    PubMed

    Harel, Elad; Schröder, Leif; Xu, Shoujun

    2008-01-01

    Nuclear magnetic resonance (NMR) is a well-established analytical technique in chemistry. The ability to precisely control the nuclear spin interactions that give rise to the NMR phenomenon has led to revolutionary advances in fields as diverse as protein structure determination and medical diagnosis. Here, we discuss methods for increasing the sensitivity of magnetic resonance experiments, moving away from the paradigm of traditional NMR by separating the encoding and detection steps of the experiment. This added flexibility allows for diverse applications ranging from lab-on-a-chip flow imaging and biological sensors to optical detection of magnetic resonance imaging at low magnetic fields. We aim to compare and discuss various approaches for a host of problems in material science, biology, and physics that differ from the high-field methods routinely used in analytical chemistry and medical imaging.

  20. Nuclear-resonance magnetometer with flowing liquid for superstrong inhomogeneous fields measuring

    NASA Astrophysics Data System (ADS)

    Davydov, V. V.; Dudkin, V. I.; Vologdin, V. A.

    2016-03-01

    Multichannel nuclear-resonance magnetometer for remote monitoring of induction and heterogeneity of a magnetic field in different areas inside and near a charged particle accelerator is considered. The maximal distance between the nuclear magnetic resonance signal detector and the magnetometer is 50 m. Measurement error is 0.5%, sensitivity of the magnetometer is 10-10 T/Hz1/2, measurement time of the magnetic field parameters in 24 control points is no more than 4 minutes.

  1. 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…

  2. Nuclear spin conversion of water inside fullerene cages detected by low-temperature nuclear magnetic resonance

    SciTech Connect

    Mamone, Salvatore Concistrè, Maria; Carignani, Elisa; Meier, Benno; Krachmalnicoff, Andrea; Johannessen, Ole G.; Denning, Mark; Carravetta, Marina; Whitby, Richard J.; Levitt, Malcolm H.; Lei, Xuegong; Li, Yongjun; Goh, Kelvin; Horsewill, Anthony J.

    2014-05-21

    The water-endofullerene H{sub 2}O@C{sub 60} provides a unique chemical system in which freely rotating water molecules are confined inside homogeneous and symmetrical carbon cages. The spin conversion between the ortho and para species of the endohedral H{sub 2}O was studied in the solid phase by low-temperature nuclear magnetic resonance. The experimental data are consistent with a second-order kinetics, indicating a bimolecular spin conversion process. Numerical simulations suggest the simultaneous presence of a spin diffusion process allowing neighbouring ortho and para molecules to exchange their angular momenta. Cross-polarization experiments found no evidence that the spin conversion of the endohedral H{sub 2}O molecules is catalysed by {sup 13}C nuclei present in the cages.

  3. Description of nuclear octupole and quadrupole deformation close to axial symmetry: Critical-point behavior of {sup 224}Ra and {sup 224}Th

    SciTech Connect

    Bizzeti, P. G.; Bizzeti-Sona, A. M.

    2008-02-15

    The model, introduced in a previous paper, for the description of the octupole and quadrupole degrees of freedom in conditions close to axial symmetry, is applied to situations of shape phase transitions where the quadrupole amplitude can reach zero. The transitional nuclei {sup 224,226}Ra and {sup 224}Th are discussed in the frame of this model. Their level schemes can be reasonably accounted for by assuming a square-well potential in two dimensions. Electromagnetic transition amplitudes are also evaluated and compared with existing experimental data.

  4. Measurement of untruncated nuclear spin interactions via zero- to ultralow-field nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Blanchard, J. W.; Sjolander, T. F.; King, J. P.; Ledbetter, M. P.; Levine, E. H.; Bajaj, V. S.; Budker, D.; Pines, A.

    2015-12-01

    Zero- to ultralow-field nuclear magnetic resonance (ZULF NMR) provides a new regime for the measurement of nuclear spin-spin interactions free from the effects of large magnetic fields, such as truncation of terms that do not commute with the Zeeman Hamiltonian. One such interaction, the magnetic dipole-dipole coupling, is a valuable source of spatial information in NMR, though many terms are unobservable in high-field NMR, and the coupling averages to zero under isotropic molecular tumbling. Under partial alignment, this information is retained in the form of so-called residual dipolar couplings. We report zero- to ultralow-field NMR measurements of residual dipolar couplings in acetonitrile-2-13C aligned in stretched polyvinyl acetate gels. This permits the investigation of dipolar couplings as a perturbation on the indirect spin-spin J coupling in the absence of an applied magnetic field. As a consequence of working at zero magnetic field, we observe terms of the dipole-dipole coupling Hamiltonian that are invisible in conventional high-field NMR. This technique expands the capabilities of zero- to ultralow-field NMR and has potential applications in precision measurement of subtle physical interactions, chemical analysis, and characterization of local mesoscale structure in materials.

  5. Nuclear Resonance Fluorescence to Measure Plutonium Mass in Spent Nuclear Fuel

    SciTech Connect

    Ludewigt, Bernhard A; Quiter, Brian J.; Ambers, Scott D.

    2011-01-14

    The Next Generation Safeguard Initiative (NGSI) of the U.S Department of Energy is supporting a multi-lab/university collaboration to quantify the plutonium (Pu) mass in spent nuclear fuel (SNF) assemblies and to detect the diversion of pins with non-destructive assay (NDA) methods. The following 14 NDA techniques are being studied: Delayed Neutrons, Differential Die-Away, Differential Die-Away Self-Interrogation, Lead Slowing Down Spectrometer, Neutron Multiplicity, Passive Neutron Albedo Reactivity, Total Neutron (Gross Neutron), X-Ray Fluorescence, {sup 252}Cf Interrogation with Prompt Neutron Detection, Delayed Gamma, Nuclear Resonance Fluorescence, Passive Prompt Gamma, Self-integration Neutron Resonance Densitometry, and Neutron Resonance Transmission Analysis. Understanding and maturity of the techniques vary greatly, ranging from decades old, well-understood methods to new approaches. Nuclear Resonance Fluorescence (NRF) is a technique that had not previously been studied for SNF assay or similar applications. Since NRF generates isotope-specific signals, the promise and appeal of the technique lies in its potential to directly measure the amount of a specific isotope in an SNF assay target. The objectives of this study were to design and model suitable NRF measurement methods, to quantify capabilities and corresponding instrumentation requirements, and to evaluate prospects and the potential of NRF for SNF assay. The main challenge of the technique is to achieve the sensitivity and precision, i.e., to accumulate sufficient counting statistics, required for quantifying the mass of Pu isotopes in SNF assemblies. Systematic errors, considered a lesser problem for a direct measurement and only briefly discussed in this report, need to be evaluated for specific instrument designs in the future. Also, since the technical capability of using NRF to measure Pu in SNF has not been established, this report does not directly address issues such as cost, size

  6. Nuclear Magnetic Resonance Study of High Temperature Superconductivity

    NASA Astrophysics Data System (ADS)

    Mounce, Andrew M.

    The high temperature superconductors HgBa2CuO 4+delta (Hg1201) and Bi2SrCa2Cu2O 8+delta (Bi2212) have been treated with 17O for both nuclear magnetic resonance (NMR) sensitivity and various electronic properties. Subsequently, NMR experiments were performed on Hg1201 and Bi2212 to reveal the nature of the pseudogap, in the normal state, and vortex phases, in the superconducting state. NMR has been performed on 17O in an underdoped Hg1201 crystal with a superconducting transition transition temperature of 74 K to look for circulating orbital currents proposed theoretically and inferred from neutron scattering. The measurements reveal narrow spectra which preclude static local fields in the pseudogap phase at the apical site, suggesting that the moments observed with neutrons are fluctuating or the orbital current ordering is not the correct model for the neutron scattering observation. The fine detail of the NMR frequency shifts at the apical oxygen site are consistent with a dipolar field from the Cu+2 site and diamagnetism below the superconducting transition. It has been predicted that superconducting vortices should be electrically charged and that this effect is particularly enhanced for high temperature superconductors. Here it is shown that the Abrikosov vortex lattice, characteristic of the mixed state of superconductors, will become unstable at sufficiently high magnetic field if there is charge trapped on the vortex core for highly anisotropic superconductors. NMR measurements of the magnetic fields generated by vortices in Bi2212 single crystals provide evidence for an electro-statically driven vortex lattice reconstruction with the magnitude of charge on each vortex pancake of 2x10-3e, depending on doping, in line with theoretical estimates. Competition with magnetism is at the heart of high temperature superconductivity, most intensely felt near a vortex core. To investigate vortex magnetism spatially resolved NMR has been used, finding a strongly non

  7. Microstructure of Wet Cement Pastes: a Nuclear Magnetic Resonance Study

    NASA Astrophysics Data System (ADS)

    Jehng, Jyh-Yuar

    1995-01-01

    Nuclear magnetic resonance relaxation analysis has been applied to interpret the evolution of microstructure in a cement paste during hydration. The work in this thesis has yielded a better understanding of the geometric and physical characterization of porous materials, and specifically cement pastes. A basic understanding of the wet-dry and freeze-thaw processes of cement pastes has been developed. The pore structure evolution has been studied by the suppression of the freezing temperature of water and compared with relaxation analysis performed at room temperature. Both methods consistently show that hydrating cement pastes have two principal components in their size distribution. Firstly, in situ measurements have been made of the water consumption, the total specific surface area, and pore water size distribution as a function of hydration time. The amount of evaporable water in the pore space can be determined from the magnitude of the NMR signal, and the NMR relaxation times provide a measure of the characteristic pore sizes. Drying studies have been performed to determine the surface spin-spin relaxation time. The NMR results on evolution of cement pore structure with hydration clearly show five different stages. The water consumption was determined to be a linear function of the logarithm of hydration time over a wide range during which the total surface area of the wet gel remains constant. These experiments support a model of capillary and gel pores in the cement paste and provide strong evidence of a stable dense-gel structure. Secondly, supercooling and thawing point depression of confined water has been studied systematically. The depression of the freezing point of liquid water confined within a pore was found to be dependent on the pore size with capillary pore water freezing at 240 K and the remaining gel pore water freezing over a temperature range extending to as low as 160 K. Finally, an important application of NMR has been developed to monitor

  8. Dynamics of Protein Kinases: Insights from Nuclear Magnetic Resonance

    PubMed Central

    Xiao, Yao; Liddle, Jennifer C.; Pardi, Arthur; Ahn, Natalie G.

    2015-01-01

    CONSPECTUS Protein kinases are ubiquitous enzymes with critical roles in cellular processes and pathology. As a result, researchers have studied their activity and regulatory mechanisms extensively. Thousands of X-ray structures give snapshots of the architectures of protein kinases in various states of activation and ligand binding. However, the extent of and manner by which protein motions and conformational dynamics underlie the function and regulation of these important enzymes is not well understood. Nuclear magnetic resonance (NMR) methods provide complementary information about protein conformation and dynamics in solution. However, until recently, the large size of these enzymes prevented researchers from using these methods with kinases. Developments in transverse relaxation-optimized spectroscopy (TROSY)-based techniques and more efficient isotope labeling strategies are now allowing researchers to carry out NMR studies on full-length protein kinases. In this Account, we describe recent insights into the role of dynamics in protein kinase regulation and catalysis that have been gained from NMR measurements of chemical shift changes and line broadening, residual dipolar couplings, and relaxation. These findings show strong associations between protein motion and events that control kinase activity. Dynamic and conformational changes occurring at ligand binding sites and other regulatory domains of these proteins propagate to conserved kinase core regions that mediate catalytic function. NMR measurements of slow time scale (microsecond to millisecond) motions also reveal that kinases carry out global exchange processes that synchronize multiple residues and allosteric interconversion between conformational states. Activating covalent modifications or ligand binding to form the Michaelis complex can induce these global processes. Inhibitors can also exploit the exchange properties of kinases by using conformational selection to form dynamically quenched

  9. Nuclear magnetic resonance of laser-polarized noble gases in molecules, materials and organisms

    SciTech Connect

    Goodson, Boyd M.

    1999-12-01

    Conventional nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI) are fundamentally challenged by the insensitivity that stems from the ordinarily low spin polarization achievable in even the strongest NMR magnets. However, by transferring angular momentum from laser light to electronic and nuclear spins, optical pumping methods can increase the nuclear spin polarization of noble gases by several orders of magnitude, thereby greatly enhancing their NMR sensitivity. This dissertation is primarily concerned with the principles and practice of optically pumped nuclear magnetic resonance (OPNMR). The enormous sensitivity enhancement afforded by optical pumping noble gases can be exploited to permit a variety of novel NMR experiments across many disciplines. Many such experiments are reviewed, including the void-space imaging of organisms and materials, NMR and MRI of living tissues, probing structure and dynamics of molecules in solution and on surfaces, and zero-field NMR and MRI.

  10. Superconducting magnetic quadrupole

    SciTech Connect

    Kim, J.W.; Shepard, K.W.; Nolen, J.A.

    1995-08-01

    A design was developed for a 350 T/m, 2.6-cm clear aperture superconducting quadrupole focussing element for use in a very low q/m superconducting linac as discussed below. The quadrupole incorporates holmium pole tips, and a rectangular-section winding using standard commercially-available Nb-Ti wire. The magnet was modeled numerically using both 2D and 3D codes, as a basis for numerical ray tracing using the quadrupole as a linac element. Components for a prototype singlet are being procured during FY 1995.

  11. A preliminary quadrupole asymmetry study of a β=0.12 superconducting single spoke cavity

    NASA Astrophysics Data System (ADS)

    Yang, Zi-Qin; Lu, Xiang-Yang; Yang, Liu; Luo, Xing; Zhou, Kui; Quan, Sheng-Wen

    2014-10-01

    An Accelerator Driven System (ADS) has been launched in China for nuclear waste transmutation. For the application of high intensity proton beam acceleration, the quadrupole asymmetry effect needs to be carefully evaluated for cavities. Single spoke cavities are the main accelerating structures in the low energy front-end. The single spoke cavity has small transverse electromagnetic field asymmetry, which may lead to transverse RF defocusing asymmetry and beam envelope asymmetry. A superconducting single spoke resonator (PKU-2 Spoke) of β=0.12 and f=325 MHz with a racetrack-shaped inner conductor has been designed at Peking university. The study of its RF field quadrupole asymmetry and its effect on transverse momentum change has been performed. The quadrupole asymmetry study has also been performed on a β=0.12 and f=325 MHz ring-shaped single spoke cavity. Our results show that the quadrupole asymmetry is very small for both the racetrack-shaped and the ring-shaped single spoke cavity.

  12. Solid state nuclear magnetic resonance investigations of advanced energy materials

    NASA Astrophysics Data System (ADS)

    Bennett, George D.

    In order to better understand the physical electrochemical changes that take place in lithium ion batteries and asymmetric hybrid supercapacitors solid state nuclear magnetic resonance (NMR) spectroscopy has been useful to probe and identify changes on the atomic and molecular level. NMR is used to characterize the local environment and investigate the dynamical properties of materials used in electrochemical storage devices (ESD). NMR investigations was used to better understand the chemical composition of the solid electrolyte interphase which form on the negative and positive electrodes of lithium batteries as well as identify the breakdown products that occur in the operation of the asymmetric hybrid supercapacitors. The use of nano-structured particles in the development of new materials causes changes in the electrical, structural and other material properties. NMR was used to investigate the affects of fluorinated and non fluorinated single wall nanotubes (SWNT). In this thesis three experiments were performed using solid state NMR samples to better characterize them. The electrochemical reactions of a lithium ion battery determine its operational profile. Numerous means have been employed to enhance battery cycle life and operating temperature range. One primary means is the choice and makeup of the electrolyte. This study focuses on the characteristics of the solid electrolyte interphase (SEI) that is formed on the electrodes surface during the charge discharge cycle. The electrolyte in this study was altered with several additives in order to determine the influence of the additives on SEI formation as well as the intercalation and de-intercalation of lithium ions in the electrodes. 7Li NMR studies where used to characterize the SEI and its composition. Solid state NMR studies of the carbon enriched acetonitrile electrolyte in a nonaqueous asymmetric hybrid supercapacitor were performed. Magic angle spinning (MAS) coupled with cross polarization NMR

  13. The direct injection of intense ion beams from a high field electron cyclotron resonance ion source into a radio frequency quadrupole

    SciTech Connect

    Rodrigues, G. Kanjilal, D.; Roy, A.; Becker, R.; Baskaran, R.

    2014-02-15

    The ion current achievable from high intensity ECR sources for highly charged ions is limited by the high space charge. This makes classical extraction systems for the transport and subsequent matching to a radio frequency quadrupole (RFQ) accelerator less efficient. The direct plasma injection (DPI) method developed originally for the laser ion source avoids these problems and uses the combined focusing of the gap between the ion source and the RFQ vanes (or rods) and the focusing of the rf fields from the RFQ penetrating into this gap. For high performance ECR sources that use superconducting solenoids, the stray magnetic field of the source in addition to the DPI scheme provides focusing against the space charge blow-up of the beam. A combined extraction/matching system has been designed for a high performance ECR ion source injecting into an RFQ, allowing a total beam current of 10 mA from the ion source for the production of highly charged {sup 238}U{sup 40+} (1.33 mA) to be injected at an ion source voltage of 60 kV. In this design, the features of IGUN have been used to take into account the rf-focusing of an RFQ channel (without modulation), the electrostatic field between ion source extraction and the RFQ vanes, the magnetic stray field of the ECR superconducting solenoid, and the defocusing space charge of an ion beam. The stray magnetic field is shown to be critical in the case of a matched beam.

  14. The direct injection of intense ion beams from a high field electron cyclotron resonance ion source into a radio frequency quadrupole.

    PubMed

    Rodrigues, G; Becker, R; Hamm, R W; Baskaran, R; Kanjilal, D; Roy, A

    2014-02-01

    The ion current achievable from high intensity ECR sources for highly charged ions is limited by the high space charge. This makes classical extraction systems for the transport and subsequent matching to a radio frequency quadrupole (RFQ) accelerator less efficient. The direct plasma injection (DPI) method developed originally for the laser ion source avoids these problems and uses the combined focusing of the gap between the ion source and the RFQ vanes (or rods) and the focusing of the rf fields from the RFQ penetrating into this gap. For high performance ECR sources that use superconducting solenoids, the stray magnetic field of the source in addition to the DPI scheme provides focusing against the space charge blow-up of the beam. A combined extraction/matching system has been designed for a high performance ECR ion source injecting into an RFQ, allowing a total beam current of 10 mA from the ion source for the production of highly charged (238)U(40+) (1.33 mA) to be injected at an ion source voltage of 60 kV. In this design, the features of IGUN have been used to take into account the rf-focusing of an RFQ channel (without modulation), the electrostatic field between ion source extraction and the RFQ vanes, the magnetic stray field of the ECR superconducting solenoid, and the defocusing space charge of an ion beam. The stray magnetic field is shown to be critical in the case of a matched beam.

  15. The direct injection of intense ion beams from a high field electron cyclotron resonance ion source into a radio frequency quadrupole

    NASA Astrophysics Data System (ADS)

    Rodrigues, G.; Becker, R.; Hamm, R. W.; Baskaran, R.; Kanjilal, D.; Roy, A.

    2014-02-01

    The ion current achievable from high intensity ECR sources for highly charged ions is limited by the high space charge. This makes classical extraction systems for the transport and subsequent matching to a radio frequency quadrupole (RFQ) accelerator less efficient. The direct plasma injection (DPI) method developed originally for the laser ion source avoids these problems and uses the combined focusing of the gap between the ion source and the RFQ vanes (or rods) and the focusing of the rf fields from the RFQ penetrating into this gap. For high performance ECR sources that use superconducting solenoids, the stray magnetic field of the source in addition to the DPI scheme provides focusing against the space charge blow-up of the beam. A combined extraction/matching system has been designed for a high performance ECR ion source injecting into an RFQ, allowing a total beam current of 10 mA from the ion source for the production of highly charged 238U40+ (1.33 mA) to be injected at an ion source voltage of 60 kV. In this design, the features of IGUN have been used to take into account the rf-focusing of an RFQ channel (without modulation), the electrostatic field between ion source extraction and the RFQ vanes, the magnetic stray field of the ECR superconducting solenoid, and the defocusing space charge of an ion beam. The stray magnetic field is shown to be critical in the case of a matched beam.

  16. Effects of projectile resonances on the total, Coulomb, and nuclear breakup cross sections in the 6Li+152Sm reaction

    NASA Astrophysics Data System (ADS)

    Mukeru, B.; Lekala, M. L.

    2016-08-01

    In this paper we analyze the effects of the projectile resonances on the total, Coulomb, and nuclear breakup cross sections as well as on the Coulomb-nuclear interferences at different arbitrary incident energies. It is found that these resonances have non-negligible effects on the total, Coulomb, and nuclear breakup cross sections. Qualitatively, they have no effects on the constructiveness or destructiveness of the Coulomb-nuclear interferences. Quantitatively, we obtained that these resonances increase by 7.38%, 7.58%, and 20.30% the integrated total, Coulomb, and nuclear breakup cross sections, respectively at Elab=35 MeV . This shows that the nuclear breakup cross sections are more affected by the effects of the projectile resonances than their total and Coulomb breakup counterparts. We also obtain that the effects of the resonances on the total, Coulomb, and nuclear breakup cross sections decrease as the incident energy increases.

  17. Coulomb and nuclear excitations of narrow resonances in 17Ne

    NASA Astrophysics Data System (ADS)

    Marganiec, J.; Wamers, F.; Aksouh, F.; Aksyutina, Yu.; Álvarez-Pol, H.; Aumann, T.; Beceiro-Novo, S.; Bertulani, C. A.; Boretzky, K.; Borge, M. J. G.; Chartier, M.; Chatillon, A.; Chulkov, L. V.; Cortina-Gil, D.; Emling, H.; Ershova, O.; Fraile, L. M.; Fynbo, H. O. U.; Galaviz, D.; Geissel, H.; Heil, M.; Hoffmann, D. H. H.; Hoffmann, J.; Johansson, H. T.; Jonson, B.; Karagiannis, C.; Kiselev, O. A.; Kratz, J. V.; Kulessa, R.; Kurz, N.; Langer, C.; Lantz, M.; Le Bleis, T.; Lemmon, R.; Litvinov, Yu. A.; Mahata, K.; Müntz, C.; Nilsson, T.; Nociforo, C.; Nyman, G.; Ott, W.; Panin, V.; Paschalis, S.; Perea, A.; Plag, R.; Reifarth, R.; Richter, A.; Rodriguez-Tajes, C.; Rossi, D.; Riisager, K.; Savran, D.; Schrieder, G.; Simon, H.; Stroth, J.; Sümmerer, K.; Tengblad, O.; Typel, S.; Weick, H.; Wiescher, M.; Wimmer, C.

    2016-08-01

    New experimental data for dissociation of relativistic 17Ne projectiles incident on targets of lead, carbon, and polyethylene targets at GSI are presented. Special attention is paid to the excitation and decay of narrow resonant states in 17Ne. Distributions of internal energy in the 15O + p + p three-body system have been determined together with angular and partial-energy correlations between the decay products in different energy regions. The analysis was done using existing experimental data on 17Ne and its mirror nucleus 17N. The isobaric multiplet mass equation is used for assignment of observed resonances and their spins and parities. A combination of data from the heavy and light targets yielded cross sections and transition probabilities for the Coulomb excitations of the narrow resonant states. The resulting transition probabilities provide information relevant for a better understanding of the 17Ne structure.

  18. Theoretical Study of the Electrostatic and Steric Effects on the Spectroscopic Characteristics of the Metal-Ligand Unit of Heme Proteins. 2. C-O Vibrational Frequencies, 17O Isotropic Chemical Shifts, and Nuclear Quadrupole Coupling Constants

    PubMed Central

    Kushkuley, Boris; Stavrov, Solomon S.

    1997-01-01

    The quantum chemical calculations, vibronic theory of activation, and London-Pople approach are used to study the dependence of the C-O vibrational frequency, 17O isotropic chemical shift, and nuclear quadrupole coupling constant on the distortion of the porphyrin ring and geometry of the CO coordination, changes in the iron-carbon and iron-imidazole distances, magnitude of the iron displacement out of the porphyrin plane, and presence of the charged groups in the heme environment. It is shown that only the electrostatic interactions can cause the variation of all these parameters experimentally observed in different heme proteins, and the heme distortions could modulate this variation. The correlations between the theoretically calculated parameters are shown to be close to the experimentally observed ones. The study of the effect of the electric field of the distal histidine shows that the presence of the four C-O vibrational bands in the infrared absorption spectra of the carbon monoxide complexes of different myoglobins and hemoglobins can be caused by the different orientations of the different tautomeric forms of the distal histidine. The dependence of the 17O isotropic chemical shift and nuclear quadrupole coupling constant on pH and the distal histidine substitution can be also explained from the same point of view. PMID:9017215

  19. Nuclear quadrupole spin-lattice relaxation in Bi{sub 4}Ge{sub 3}O{sub 12} single crystals doped with atoms of d or f elements. Crystal field effects in compounds exhibiting anomalous magnetic properties

    SciTech Connect

    Orlov, V. G. Sergeev, G. S.; Asaji, Tetsuo; Kravchenko, E. A.; Kargin, Yu. F.

    2010-02-15

    The nuclear quadrupole spin-lattice relaxation was studied in the range 4.2-300 K for single crystals of Bi{sub 4}Ge{sub 3}O{sub 12} doped with minor amounts (the tenth fractions of mol%) of paramagnetic atoms of Cr, Nd, and Gd. Unusual spin dynamic features were recently found for these crystals at room temperature: a dramatic (up to 8-fold) increase in the effective nuclear quadrupole spin-spin relaxation time T{sub 2}* occurred upon doping the pure Bi{sub 4}Ge{sub 3}O{sub 12} sample. Unlike T{sub 2}*, the effective spin-lattice relaxation time T{sub 1}* at room temperature differs insignificantly for both doped and pure samples. But at lower temperatures, the samples exhibit considerably different behavior of the spin-lattice relaxation with temperature, which is caused by different contributions to the relaxation process of the dopant paramagnetic atoms. The distinctive maximum in the temperature dependence of the spin-lattice relaxation time for the Nd-doped crystal is shown to result from the crystal electric field effects.

  20. Use of nuclear resonant scattering of gamma rays for in vivo measurement of iron

    SciTech Connect

    Vartsky, D.; Wielopolski, L.; Ellis, K.J.; Cohn, S.H.

    1981-01-01

    A technique for determination of elements in human body in-vivo, utilizing nuclear resonant scattering of gamma rays has been developed. 847 keV photons emitted from a gaseous /sup 56/MnCl/sub 2/ source are resonantly scattered from /sup 56/Fe present in the body. The detection of these gamma rays is used to estimate the iron content of the liver or heart of patients. Details of the calibration procedure and potential molecular effects are described.

  1. p-p minimum-bias dijets and nonjet quadrupole in relation to conjectured collectivity (flows) in high-energy nuclear collisions

    NASA Astrophysics Data System (ADS)

    Trainor, Thomas A.

    2016-07-01

    Recent observations of ridge-like structure in p-p and p-A angular correlations at the RHIC and LHC have been interpreted to imply collective motion in smaller collision systems. It is argued that if correlation structures accepted as manifestations of flow in A-A collisions appear in smaller systems collectivity (flow) must extend to the smaller systems. But the argument could be reversed to conclude that such structures appearing in A-A collisions may not imply hydrodynamic flow. I present spectrum, correlation and fluctuation data from RHIC p-p and Au-Au collisions and p-p, p-Pb and Pb-Pb results from the LHC described accurately by a two-component (soft+dijet) model of hadron production. I also present evidence for a significant p-p nonjet (NJ) quadrupole (v2) component with nch systematics directly related to A-A NJ quadrupole systematics. The combination suggests that soft, dijet and NJ quadrupole com- ponents are distinct phenomena in all cases, inconsistent with hadron production from a common bulk medium exhibiting collective motion (flow).

  2. Quadrupole photoionization of hydrogen atoms in Debye plasmas

    SciTech Connect

    Lin, C. Y.; Ho, Y. K.

    2010-09-15

    Although a great deal of effort has been devoted to investigating dipole photoionization of plasma-embedded atoms, far less is known about the corresponding quadrupole transitions. In the present work, quadrupole photoionization processes for the ground and excited states of hydrogen atoms in Debye plasma are explored using the method of complex coordinate rotation. The plasma shielding effects on the quadrupole photoionization cross sections are reported for a variety of Debye screening lengths and compared to the dipole results accordingly. Under the perturbation of plasma screening, shape resonances and Cooper-type minima occurring in both dipole and quadrupole photoionization cross sections are presented and discussed. Comparisons are made to other theoretical calculations for the dipole photoionization with good agreement. The present quadrupole results are the first predictions for hydrogen photoionization in Debye plasmas.

  3. Correcting Quadrupole Roll in Magnetic Lenses with Skew Quadrupoles

    SciTech Connect

    Walstrom, Peter Lowell

    2014-11-10

    Quadrupole rolls (i.e. rotation around the magnet axis) are known to be a significant source of image blurring in magnetic quadrupole lenses. These rolls may be caused by errors in mechanical mounting of quadrupoles, by uneven radiation-induced demagnetization of permanent-magnet quadrupoles, etc. Here a four-quadrupole ×10 lens with so-called ”Russian” or A -B B-A symmetry is used as a model problem. Existing SLAC 1/2 in. bore high-gradient quadrupoles are used in the design. The dominant quadrupole roll effect is changes in the first-order part of the transfer map (the R matrix) from the object to the image plane (Note effects on the R matrix can be of first order in rotation angle for some R-matrix elements and second order in rotation angle for other elements, as shown below). It is possible to correct roll-induced image blur by mechanically adjusting the roll angle of one or more of the quadrupoles. Usually, rotation of one quadrupole is sufficient to correct most of the combined effect of rolls in all four quadrupoles. There are drawbacks to this approach, however, since mechanical roll correction requires multiple entries into experimental area to make the adjustments, which are made according to their effect on images. An alternative is to use a single electromagnetic skew quadrupole corrector placed either between two of the quadrupoles or after the fourth quadrupole (so-called “non-local” correction). The basic feasibility of skew quadrupole correction of quadrupole roll effects is demonstrated here. Rolls of the third lens quadrupole of up to about 1 milliradian can be corrected with a 15 cm long skew quadrupole with a gradient of up to 1 T/m. Since the effect of rolls of the remaining three lens quadrupoles are lower, a weaker skew quadrupole can be used to correct them. Non-local correction of quadrupole roll effects by skew quadrupoles is shown to be about one-half as effective as local correction (i.e. rotating individual quadrupoles to zero

  4. The Trojan Horse method for nuclear astrophysics: Recent results on resonance reactions

    SciTech Connect

    Cognata, M. La; Pizzone, R. G.; Spitaleri, C.; Cherubini, S.; Romano, S.; Gulino, M.; Tumino, A.; Lamia, L.

    2014-05-09

    Nuclear astrophysics aims to measure nuclear-reaction cross sections of astrophysical interest to be included into models to study stellar evolution and nucleosynthesis. Low energies, < 1 MeV or even < 10 keV, are requested for this is the window where these processes are more effective. Two effects have prevented to achieve a satisfactory knowledge of the relevant nuclear processes, namely, the Coulomb barrier exponentially suppressing the cross section and the presence of atomic electrons. These difficulties have triggered theoretical and experimental investigations to extend our knowledge down to astrophysical energies. For instance, indirect techniques such as the Trojan Horse Method have been devised yielding new cutting-edge results. In particular, I will focus on the application of this indirect method to resonance reactions. Resonances might dramatically enhance the astrophysical S(E)-factor so, when they occur right at astrophysical energies, their measurement is crucial to pin down the astrophysical scenario. Unknown or unpredicted resonances might introduce large systematic errors in nucleosynthesis models. These considerations apply to low-energy resonances and to sub-threshold resonances as well, as they may produce sizable modifications of the S-factor due to, for instance, destructive interference with another resonance.

  5. Nuclear magnetic resonance micro-imaging in the investigation of plant cell metabolism.

    PubMed

    Köckenberger, W

    2001-04-01

    Micro-imaging based on nuclear magnetic resonance offers the possibility to map metabolites in plant tissues non-invasively. Major metabolites such as sucrose and amino acids can be observed with high spatial resolution. Stable isotope tracers, such as (13)C-labelled metabolites can be used to measure the in vivo conversion rates in a metabolic network. This review summarizes the different nuclear magnetic resonance micro-imaging techniques that are available to obtain spatially resolved information on metabolites in plants. A short general introduction into NMR imaging techniques is provided. Particular emphasis is given to the difficulties encountered when NMR micro-imaging is applied to plant systems.

  6. Observation of Fe-H/D modes by nuclear resonant vibrational spectroscopy.

    PubMed

    Bergmann, Uwe; Sturhahn, Wolfgang; Linn, Donald E; Jenney, Francis E; Adams, Michael W W; Rupnik, Kresimir; Hales, Brian J; Alp, Ercan E; Mayse, Aaron; Cramer, Stephen P

    2003-04-01

    Metal-hydrogen bonding is important in chemistry and catalysis, but H atoms are often difficult to observe, especially in metalloproteins. In this work we show that Fe-H interactions can be probed by nuclear resonance vibrational spectroscopy at the 14.4 keV 57Fe nuclear resonance. An important advantage of this method, compared to Raman and IR spectroscopy, is the selectivity for modes that involve 57Fe motion. We present data on the FeS4 site in rubredoxin and the [FeH(D)6]2- ion. Prospects for studying more complex systems are discussed.

  7. Observation of Fe-H/D Modes by Nuclear Resonant Vibrational Spectroscopy

    SciTech Connect

    Bergman, U B; Sturhahn, W; Linn, D E; Jenny, F E; Adams, M W. W.; Rupnik, K; Hales, B J; Alp, E E; Mayse, A; Cramer, S P; XFD,

    2003-04-01

    Metal-hydrogen bonding is important in chemistry and catalysis, but H atoms are often difficult to observe, especially in metalloproteins. In this work we show that Fe-H interactions can be probed by nuclear resonance vibrational spectroscopy at the 14.4 keV 57Fe nuclear resonance. An important advantage of this method, compared to Raman and IR spectroscopy, is the selectivity for modes that involve {sup 57}Fe motion. We present data on the FeS{sub 4} site in rubredoxin and the [FeH(D){sub 6}]{sup 2-} ion. Prospects for studying more complex systems are discussed.

  8. Nuclear clusters studied with alpha resonant scatterings using RI beams at CRIB

    NASA Astrophysics Data System (ADS)

    Yamaguchi, H.; Kahl, D.; Nakao, T.; Wakabayashi, Y.; Hashimoto, T.; Hayakawa, S.; Kawabata, T.; Teranishi, T.; Kwon, Y. K.; Binh, D. N.; Khiem, L. H.; Duy, N. N.; Kubono, S.; Suhara, T.; Kanada-En'yo, Y.; Moon, J. Y.; Kim, A.; Iwasa, N.; Lee, P. S.; Chae, K. Y.; Cha, S. M.; Gwak, M. S.; Kim, D. H.; Milman, E.

    2014-12-01

    Alpha resonant scattering is a simple and promising method to study α-cluster structure in nuclei. It has several good features which enable us to perform measurements with short-lived and relatively low-intense RI beams. Several measurements on alpha resonant scattering have been carried out 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. Recent α resonant scattering studies at CRIB, using 7Li, 7Be and 10Be beams with a helium gas target, are discussed.

  9. 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

  10. Nuclear Waste Cross Site Transfer Pump Operational Resonance Resolution

    SciTech Connect

    HAUCK, F.M.

    1999-12-01

    Two single-volute, multi-stage centrifugal pumps are installed at a nuclear waste transfer station operated by the Department of Energy in Hanford, WA. The two parallel 100% pumps are Variable Frequency Drive operated and designed to transport waste etc.

  11. High homogeneity B(1) 30.2 MHz Nuclear Magnetic Resonance Probe for off-resonance relaxation times measurements.

    PubMed

    Baranowski, M; Woźniak-Braszak, A; Jurga, K

    2011-01-01

    This paper reports on design and construction of a double coil high-homogeneity ensuring Nuclear Magnetic Resonance Probe for off-resonance relaxation time measurements. NMR off-resonance experiments pose unique technical problems. Long irradiation can overheat the sample, dephase the spins because of B(1) field inhomogeneity and degrade the signal received by requiring the receiver bandwidth to be broader than that needed for normal experiment. The probe proposed solves these problems by introducing a separate off-resonance irradiation coil which is larger than the receiver coil and is wound up on the dewar tube that separates it from the receiver coil thus also thermally protects the sample from overheating. Large size of the irradiation coil also improves the field homogeneity because as a ratio of the sample diameter to the magnet (coil) diameter increases, the field inhomogeneity also increases (Blümich et al., 2008) [1]. The small receiver coil offers maximization of the filling factor and a high signal to the noise ratio.

  12. Unraveling multi-spin effects in rotational resonance nuclear magnetic resonance using effective reduced density matrix theory.

    PubMed

    SivaRanjan, Uppala; Ramachandran, Ramesh

    2014-02-01

    A quantum-mechanical model integrating the concepts of reduced density matrix and effective Hamiltonians is proposed to explain the multi-spin effects observed in rotational resonance (R(2)) nuclear magnetic resonance (NMR) experiments. Employing this approach, the spin system of interest is described in a reduced subspace inclusive of its coupling to the surroundings. Through suitable model systems, the utility of our theory is demonstrated and verified with simulations emerging from both analytic and numerical methods. The analytic results presented in this article provide an accurate description/interpretation of R(2) experimental results and could serve as a test-bed for distinguishing coherent/incoherent effects in solid-state NMR.

  13. Proton nuclear magnetic resonance studies on the variant-3 neurotoxin from Centruroides sculpturatus Ewing: Sequential assignment of resonances

    SciTech Connect

    Nettesheim, D.G.; Klevit, R.E.; Drobny, G.; Watt, D.D.; Krishna, N.R. )

    1989-02-21

    The authors report the sequential assignment of resonances to specific residues in the proton nuclear magnetic resonance spectrum of the variant-3 neurotoxin from the scorpion Centruroides sculpturatus Ewing (range southwestern U.S.A.). A combination of two-dimensional NMR experiments such as 2D-COSY, 2D-NOESY, and single- and double-RELAY coherence transfer spectroscopy has been employed on samples of the protein dissolved in D{sub 2}O and in H{sub 2}O for assignment purposes. These studies provide a basis for the determination of the solution-phase conformation of this protein and for undertaking detailed structure-function studies of these neurotoxins that modulate the flow of sodium current by binding to the sodium channels of excitable membranes.

  14. Unraveling multi-spin effects in rotational resonance nuclear magnetic resonance using effective reduced density matrix theory

    SciTech Connect

    SivaRanjan, Uppala; Ramachandran, Ramesh

    2014-02-07

    A quantum-mechanical model integrating the concepts of reduced density matrix and effective Hamiltonians is proposed to explain the multi-spin effects observed in rotational resonance (R{sup 2}) nuclear magnetic resonance (NMR) experiments. Employing this approach, the spin system of interest is described in a reduced subspace inclusive of its coupling to the surroundings. Through suitable model systems, the utility of our theory is demonstrated and verified with simulations emerging from both analytic and numerical methods. The analytic results presented in this article provide an accurate description/interpretation of R{sup 2} experimental results and could serve as a test-bed for distinguishing coherent/incoherent effects in solid-state NMR.

  15. Zero-field nuclear magnetic resonance spectroscopy of viscous liquids

    NASA Astrophysics Data System (ADS)

    Shimizu, Y.; Blanchard, J. W.; Pustelny, S.; Saielli, G.; Bagno, A.; Ledbetter, M. P.; Budker, D.; Pines, A.

    2015-01-01

    We report zero-field NMR measurements of a viscous organic liquid, ethylene glycol. Zero-field spectra were taken showing resolved scalar spin-spin coupling (J-coupling) for ethylene glycol at different temperatures and water contents. Molecular dynamics strongly affects the resonance linewidth, which closely follows viscosity. Quantum chemical calculations have been used to obtain the relative stability and coupling constants of all ethylene glycol conformers. The results show the potential of zero-field NMR as a probe of molecular structure and dynamics in a wide range of environments, including viscous fluids.

  16. The proton-neutron symplectic model of nuclear collective motions

    NASA Astrophysics Data System (ADS)

    Ganev, H. G.

    2016-06-01

    The proton-neutron symplectic model of nuclear collective motion is presented. It is shown that it appears as a natural multi-major-shell extension of the generalized proton- neutron SU(3) scheme which includes rotations with intrinsic vortex as well as monopole, quadrupole and dipole giant resonance vibrational degrees of freedom.

  17. Prototype explosives detection system based on nuclear resonance absorption in nitrogen

    SciTech Connect

    Morgado, R.E.; Arnone, G.; Cappiello, C.C.; Gardner, S.D.; Hollas, C.L.; Ussery, L.E.; White, J.M.; Zahrt, J.D.; Krauss, R.A.

    1993-12-01

    A-prototype explosives detection system that was developed for experimental evaluation of a nuclear resonance absorption techniques is described. The major subsystems are a proton accelerator and beam transport, high-temperature proton target, an airline-luggage tomographic inspection station, and an image-processing/detection- alarm subsystem. The detection system performance, based on a limited experimental test, is reported.

  18. MEMS-based force-detected nuclear magnetic resonance spectrometer for in situ planetary exploration

    NASA Technical Reports Server (NTRS)

    George, T.; Leskowitz, G.; Madsen, L.; Weitekamp, D.; Tang, W.

    2000-01-01

    Nuclear Magnetic resonance (NMR) is a well-known spectroscopic technique used by chemists and is especially powerful in detecting the presence of water and distinguishing between arbitrary physisorbed and chemisorbed states. This ability is of particular importance in the search for extra-terrestrial life on planets such as Mars.

  19. The Effect of Electronic Paramagnetism on Nuclear Magnetic Resonance Frequencies in Metals

    DOE R&D Accomplishments Database

    Townes, C. H.; Herring, C.; Knight, W. D.

    1950-09-22

    Observations on the shifts of nuclear resonances in metals ( Li{sup 7}, Na{sup 23}, Cu {sup 63}, Be{sup 9}, Pb{sup 207}, Al{sup 27}, and Ca{sup 69} ) due to free electron paramagnetism; comparison with theoretical values.

  20. Phosphorus-31 nuclear magnetic resonance chemical shifts of phosphoric acid derivatives.

    PubMed

    Wittmann, Z; Kovács, Z

    1985-07-01

    (31)P nuclear magnetic resonance chemical shifts of alkyi and alkylaryl phosphates, condensed phosphates, phosphoric arids and their salts, are reported. These are listed by classes of compounds so that relationships between chemical shifts and the substituent groups on phosphorus atoms can be recognized. These relationships are useful for qualitative identification of the specific compounds listed and of related compounds by extrapolation.

  1. The Complexation of the Na(super +) by 18-Crown-6 Studied via Nuclear Magnetic Resonance

    ERIC Educational Resources Information Center

    Peters, Steven J.; Stevenson, Cheryl D.

    2004-01-01

    A student friendly experiment that teaches several important concepts of modern nuclear magnetic resonance (NMR), like multinuclear capabilities, the NMR time scale, and time-averaged signals, is described along with some important concepts of thermo chemical equilibria. The mentioned experiment involves safe and inexpensive compounds, such as…

  2. Quantitative Analysis of Nail Polish Remover Using Nuclear Magnetic Resonance Spectroscopy Revisited

    ERIC Educational Resources Information Center

    Hoffmann, Markus M.; Caccamis, Joshua T.; Heitz, Mark P.; Schlecht, Kenneth D.

    2008-01-01

    Substantial modifications are presented for a previously described experiment using nuclear magnetic resonance (NMR) spectroscopy to quantitatively determine analytes in commercial nail polish remover. The revised experiment is intended for a second- or third-year laboratory course in analytical chemistry and can be conducted for larger laboratory…

  3. Sealed magic angle spinning nuclear magnetic resonance probe and process for spectroscopy of hazardous samples

    DOEpatents

    Cho, Herman M.; Washton, Nancy M.; Mueller, Karl T.; Sears, Jr., Jesse A.; Townsend, Mark R.; Ewing, James R.

    2016-06-14

    A magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) probe is described that includes double containment enclosures configured to seal and contain hazardous samples for analysis. The probe is of a modular design that ensures containment of hazardous samples during sample analysis while preserving spin speeds for superior NMR performance and convenience of operation.

  4. The Isoscalar Giant Dipole Resonance in {sup 20}Pb, {sup 90}Zr and the Nuclear Compressibility

    SciTech Connect

    Yildirim, Serbulent; Koeroglu, Ulas

    2008-11-11

    The isoscalar giant dipol resonance (ISGDR) in finite nuclei is studied within the framework of a relativistic transport approach. The excitation energies of spherical {sup 90}Zr and {sup 208}Pb nuclei are obtained for different quantum hydrodynamical Lagrangian parametrization. The sensitivity of ISGDR excitation energy on the nuclear bulk to surface properties are also investigated.

  5. A Noninvasive Method to Study Regulation of Extracellular Fluid Volume in Rats Using Nuclear Magnetic Resonance

    EPA Science Inventory

    Time-domain nuclear magnetic resonance (TD-NMR)-based measurement of body composition of rodents is an effective method to quickly and repeatedly measure proportions of fat, lean, and fluid without anesthesia. TD-NMR provides a measure of free water in a living animal, termed % f...

  6. Prototype explosives-detection system based on nuclear-resonance absorption in nitrogen

    SciTech Connect

    Morgado, R.E.; Arnone, G.; Cappiello, C.C.; Gardner, S.D.; Hollas, C.L.; Ussery, L.E.; White, J.M.; Zahrt, J.D.; Krauss, R.A.

    1994-06-01

    A prototype explosives-detection system (EDS) that was developed for experimental evaluation of a nuclear-resonance absorption technique is described. The major subsystems are a proton accelerator and beam transport, high-temperature proton target, an airline-luggage tomographic inspection station, and an image-processing/detection-alarm subsystem. The detection system performance, based on a limited experimental test, is reported.

  7. 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…

  8. Mechanical design parameters for detection of nuclear signals by magnetic resonance force microscopy

    SciTech Connect

    Moore, G.J.; Hanlon, J.A.; Lamartine, B.; Hawley, M.; Solem, J.C.; Signer, S.; Jarmer, J.J.; Penttila, S.; Sillerud, L.O.; Pryputniewicz, R.J.

    1993-10-01

    Recent theoretical work has shown that mechanical detection of magnetic resonance from a single nuclear spin is in principle possible. This theory has recently been experimentally validated by the mechanical detection of electron spin resonance signals using microscale cantilevers. Currently we are extending this technology in an attempt to detect nuclear signals which are extending this technology in an attempt to detect nuclear signals which are three orders of magnitude lower in intensity than electron signals. In order to achieve the needed thousand-fold improvement in sensitivity we have undertaken the development of optimized mechanical cantilevers and highly polarized samples. Finite element modeling is used as a tool to simulate cantilever beam dynamics and to optimize the mechanical properties including Q, resonant frequency, amplitude of vibration and spring constant. Simulations are compared to experiments using heterodyne hologram interferometry. Nanofabrication of optimized cantilevers via ion milling will be directed by the outcome of these simulations and experiments. Highly polarized samples are developed using a three-fold approach: (1) high magnetic field strength (2.5T), (2) low temperature (1K), and (3) use of samples polarized by dynamic nuclear polarization. Our recent experiments have demonstrated nuclear polarizations in excess of 50% in molecules of toulene.

  9. Structure Determination of Natural Products by Nuclear Magnetic Resonance Spectroscopy

    NASA Astrophysics Data System (ADS)

    Li, Du.

    High-field NMR experiments were used to determine the full structures of six new natural products extracted from plants. These are: four saponins (PT-2, P1, P2 and P3) from the plant Alphitonia zizyphoides found in Samoa; one sesquiterpene (DF-4) from Douglas fir and one diterpene derivative (E-2) from a Chinese medicinal herb. By concerted use of various 1D and 2D NMR techniques, the structures of the above compounds were established and complete resonance assignments were achieved. The 2D INADEQUATE technique coupled with a computerized spectral analysis was extensively used. When carried out on concentrations as low as 60 mg of sample, this technique provided absolute confirmation of the assignments for 35 of the possible 53 C-C bonds for PT-2. On 30 mg of sample of E-21, it revealed 22 of 28 possible C-C bonds.

  10. Measurement of Charged Pions from Neutrino-produced Nuclear Resonance

    SciTech Connect

    Simon, Clifford N.

    2014-01-01

    A method for identifying stopped pions in a high-resolution scintillator bar detector is presented. I apply my technique to measure the axial mass MΔAfor production of the Δ(1232) resonance by neutrino, with the result MΔA = 1.16±0.20 GeV (68% CL) (limited by statistics). The result is produced from the measured spectrum of reconstructed momentum-transfer Q2. I proceed by varying the value of MΔA in a Rein-Sehgal-based Monte Carlo to produce the best agreement, using shape only (not normalization). The consistency of this result with recent reanalyses of previous bubble-chamber experiments is discussed.

  11. Nuclear magnetic resonance detection and spectroscopy of single proteins using quantum logic

    NASA Astrophysics Data System (ADS)

    Lovchinsky, I.; Sushkov, A. O.; Urbach, E.; de Leon, N. P.; Choi, S.; De Greve, K.; Evans, R.; Gertner, R.; Bersin, E.; Müller, C.; McGuinness, L.; Jelezko, F.; Walsworth, R. L.; Park, H.; Lukin, M. D.

    2016-02-01

    Nuclear magnetic resonance spectroscopy is a powerful tool for the structural analysis of organic compounds and biomolecules but typically requires macroscopic sample quantities. We use a sensor, which consists of two quantum bits corresponding to an electronic spin and an ancillary nuclear spin, to demonstrate room temperature magnetic resonance detection and spectroscopy of multiple nuclear species within individual ubiquitin proteins attached to the diamond surface. Using quantum logic to improve readout fidelity and a surface-treatment technique to extend the spin coherence time of shallow nitrogen-vacancy centers, we demonstrate magnetic field sensitivity sufficient to detect individual proton spins within 1 second of integration. This gain in sensitivity enables high-confidence detection of individual proteins and allows us to observe spectral features that reveal information about their chemical composition.

  12. Nuclear magnetic resonance detection and spectroscopy of single proteins using quantum logic.

    PubMed

    Lovchinsky, I; Sushkov, A O; Urbach, E; de Leon, N P; Choi, S; De Greve, K; Evans, R; Gertner, R; Bersin, E; Müller, C; McGuinness, L; Jelezko, F; Walsworth, R L; Park, H; Lukin, M D

    2016-02-19

    Nuclear magnetic resonance spectroscopy is a powerful tool for the structural analysis of organic compounds and biomolecules but typically requires macroscopic sample quantities. We use a sensor, which consists of two quantum bits corresponding to an electronic spin and an ancillary nuclear spin, to demonstrate room temperature magnetic resonance detection and spectroscopy of multiple nuclear species within individual ubiquitin proteins attached to the diamond surface. Using quantum logic to improve readout fidelity and a surface-treatment technique to extend the spin coherence time of shallow nitrogen-vacancy centers, we demonstrate magnetic field sensitivity sufficient to detect individual proton spins within 1 second of integration. This gain in sensitivity enables high-confidence detection of individual proteins and allows us to observe spectral features that reveal information about their chemical composition.

  13. Nuclear magnetic resonance detection and spectroscopy of single proteins using quantum logic.

    PubMed

    Lovchinsky, I; Sushkov, A O; Urbach, E; de Leon, N P; Choi, S; De Greve, K; Evans, R; Gertner, R; Bersin, E; Müller, C; McGuinness, L; Jelezko, F; Walsworth, R L; Park, H; Lukin, M D

    2016-02-19

    Nuclear magnetic resonance spectroscopy is a powerful tool for the structural analysis of organic compounds and biomolecules but typically requires macroscopic sample quantities. We use a sensor, which consists of two quantum bits corresponding to an electronic spin and an ancillary nuclear spin, to demonstrate room temperature magnetic resonance detection and spectroscopy of multiple nuclear species within individual ubiquitin proteins attached to the diamond surface. Using quantum logic to improve readout fidelity and a surface-treatment technique to extend the spin coherence time of shallow nitrogen-vacancy centers, we demonstrate magnetic field sensitivity sufficient to detect individual proton spins within 1 second of integration. This gain in sensitivity enables high-confidence detection of individual proteins and allows us to observe spectral features that reveal information about their chemical composition. PMID:26847544

  14. Nuclear magnetic resonance of laser-polarized noble gases in molecules, materials, and organisms.

    PubMed

    Goodson, Boyd M

    2002-04-01

    The sensitivity of conventional nuclear magnetic resonance (NMR) techniques is fundamentally limited by the ordinarily low spin polarization achievable in even the strongest NMR magnets. However, by transferring angular momentum from laser light to electronic and nuclear spins, optical pumping methods can increase the nuclear spin polarization of noble gases by several orders of magnitude, thereby greatly enhancing their NMR sensitivity. This review describes the principles and magnetic resonance applications of laser-polarized noble gases. The enormous sensitivity enhancement afforded by optical pumping can be exploited to permit a variety of novel NMR experiments across numerous disciplines. Many such experiments are reviewed, including the void-space imaging of organisms and materials, NMR and MRI of living tissues, probing structure and dynamics of molecules in solution and on surfaces, NMR sensitivity enhancement via polarization transfer, and low-field NMR and MRI. PMID:12036331

  15. The Quadrupole Mass Spectrometer

    ERIC Educational Resources Information Center

    Matheson, E.; Harris, T. J.

    1969-01-01

    Describes the construction and operation of a quadrupole mass spectrometer for experiments in an advanced-teaching laboratory. Discusses the theory of operation of the spectrometer and the factors affecting the resolution. Some examples of mass spectra obtained with this instrument are presented and discussed. (LC)

  16. Nuclear magnetic resonance force microscopy at high magnetic field and low temperature

    NASA Astrophysics Data System (ADS)

    Marohn, John A.; Harrell, Lee H.; Thurber, Kent; Fainchtein, Raul; Smith, Doran D.

    2000-03-01

    We will report detection of nuclear magnetic resonance at 6.5 Tesla from a micron-scale sample by magnetic resonance force microscopy (MRFM) at low-temperature. We will detail a ``bare bones" one-inch diameter probe (including a novel ``string and spring" fiber positioning element, a tuned and matched RF coil, and a heating element) suitable for simple variable-temperature magnetic-resonance force microscopy studies. The compact probe design succeeded in minimizing both deleterious thermal drifts in the positions of probe components and pickup of environmental vibrations. In studying Nd-doped calcium fluoride at a magnetic field higher than has previously been employed in an MRFM experiment, we found that even sample-on-cantilever experiments can be complicated by the cantilever's resonance frequency changing with magnetic field.

  17. Nuclear hyperfine and quadrupole tensor characterization of the nitrogen hydrogen bond donors to the semiquinone of the QB site in bacterial reaction centers: a combined X- and S-band (14,15)N ESEEM and DFT study.

    PubMed

    Taguchi, Alexander T; O'Malley, Patrick J; Wraight, Colin A; Dikanov, Sergei A

    2014-02-13

    The secondary quinone anion radical QB(-) (SQB) in reaction centers of Rhodobacter sphaeroides interacts with Nδ of His-L190 and Np (peptide nitrogen) of Gly-L225 involved in hydrogen bonds to the QB carbonyls. In this work, S-band (∼3.6 GHz) ESEEM was used with the aim of obtaining a complete characterization of the nuclear quadrupole interaction (nqi) tensors for both nitrogens by approaching the cancelation condition between the isotropic hyperfine coupling and (14)N Zeeman frequency at lower microwave frequencies than traditional X-band (9.5 GHz). By performing measurements at S-band, we found a dominating contribution of Nδ in the form of a zero-field nqi triplet at 0.55, 0.92, and 1.47 MHz, defining the quadrupole coupling constant K = e(2)qQ/4h = 0.4 MHz and associated asymmetry parameter η = 0.69. Estimates of the hyperfine interaction (hfi) tensors for Nδ and Np were obtained from simulations of 1D and 2D (14,15)N X-band and three-pulse (14)N S-band spectra with all nuclear tensors defined in the SQB g-tensor coordinate system. From simulations, we conclude that the contribution of Np to the S-band spectrum is suppressed by its strong nqi and weak isotropic hfi comparable to the level of hyperfine anisotropy, despite the near-cancelation condition for Np at S-band. The excellent agreement between our EPR simulations and DFT calculations of the nitrogen hfi and nqi tensors to SQB is promising for the future application of powder ESEEM to full tensor characterizations.

  18. Nuclear hyperfine and quadrupole tensor characterization of the nitrogen hydrogen bond donors to the semiquinone of the QB site in bacterial reaction centers: a combined X- and S-band (14,15)N ESEEM and DFT study.

    PubMed

    Taguchi, Alexander T; O'Malley, Patrick J; Wraight, Colin A; Dikanov, Sergei A

    2014-02-13

    The secondary quinone anion radical QB(-) (SQB) in reaction centers of Rhodobacter sphaeroides interacts with Nδ of His-L190 and Np (peptide nitrogen) of Gly-L225 involved in hydrogen bonds to the QB carbonyls. In this work, S-band (∼3.6 GHz) ESEEM was used with the aim of obtaining a complete characterization of the nuclear quadrupole interaction (nqi) tensors for both nitrogens by approaching the cancelation condition between the isotropic hyperfine coupling and (14)N Zeeman frequency at lower microwave frequencies than traditional X-band (9.5 GHz). By performing measurements at S-band, we found a dominating contribution of Nδ in the form of a zero-field nqi triplet at 0.55, 0.92, and 1.47 MHz, defining the quadrupole coupling constant K = e(2)qQ/4h = 0.4 MHz and associated asymmetry parameter η = 0.69. Estimates of the hyperfine interaction (hfi) tensors for Nδ and Np were obtained from simulations of 1D and 2D (14,15)N X-band and three-pulse (14)N S-band spectra with all nuclear tensors defined in the SQB g-tensor coordinate system. From simulations, we conclude that the contribution of Np to the S-band spectrum is suppressed by its strong nqi and weak isotropic hfi comparable to the level of hyperfine anisotropy, despite the near-cancelation condition for Np at S-band. The excellent agreement between our EPR simulations and DFT calculations of the nitrogen hfi and nqi tensors to SQB is promising for the future application of powder ESEEM to full tensor characterizations. PMID:24437652

  19. Method of using a nuclear magnetic resonance spectroscopy standard

    DOEpatents

    Spicer, Leonard D.; Bennett, Dennis W.; Davis, Jon F.

    1985-01-01

    (CH.sub.3).sub.3 SiNSO is produced by the reaction of ((CH.sub.3).sub.3 Si).sub.2 NH with SO.sub.2. Also produced in the reaction are ((CH.sub.3).sub.3 Si).sub.2 O and a new solid compound [NH.sub.4 ][(CH.sub.3).sub.3 SiOSO.sub.2 ]. Both (CH.sub.3).sub.3 SiNSO and [NH.sub.4 ][(CH.sub.3).sub.3 SiOSO.sub.2 ] have fluorescent properties. The reaction of the subject invention is used in a method of measuring the concentration of SO.sub.2 pollutants in gases. By the method, a sample of gas is bubbled through a solution of ((CH.sub.3).sub.3 Si).sub.2 NH, whereby any SO.sub.2 present in the gas will react to produce the two fluorescent products. The measured fluorescence of these products can then be used to calculate the concentration of SO.sub.2 in the original gas sample. The solid product [NH.sub.4 ][(CH.sub.3).sub.3 SiOSO.sub.2 ] may be used as a standard in solid state NMR spectroscopy, wherein the resonance peaks of either .sup.1 H, .sup.13 C, .sup.15 N, or .sup.29 Si may be used as a reference.

  20. Quantitative nuclear magnetic resonance imaging: characterisation of experimental cerebral oedema.

    PubMed Central

    Barnes, D; McDonald, W I; Johnson, G; Tofts, P S; Landon, D N

    1987-01-01

    Magnetic resonance imaging (MRI) has been used quantitatively to define the characteristics of two different models of experimental cerebral oedema in cats: vasogenic oedema produced by cortical freezing and cytotoxic oedema induced by triethyl tin. The MRI results have been correlated with the ultrastructural changes. The images accurately delineated the anatomical extent of the oedema in the two lesions, but did not otherwise discriminate between them. The patterns of measured increase in T1' and T2' were, however, characteristic for each type of oedema, and reflected the protein content. The magnetisation decay characteristics of both normal and oedematous white matter were monoexponential for T1 but biexponential for T2 decay. The relative sizes of the two component exponentials of the latter corresponded with the physical sizes of the major tissue water compartments. Quantitative MRI data can provide reliable information about the physico-chemical environment of tissue water in normal and oedematous cerebral tissue, and are useful for distinguishing between acute and chronic lesions in multiple sclerosis. Images PMID:3572428

  1. Chemical structures in pyrodextrin determined by nuclear magnetic resonance spectroscopy.

    PubMed

    Bai, Yanjie; Shi, Yong-Cheng

    2016-10-20

    Glycosidic linkages in a pyrodextrin were identified by NMR spectroscopy for the first time. Pyrodextrin was prepared by slurrying waxy maize starch at pH 3, filtering and drying at 40°C to 10-15% moisture content, then heating at 170°C for 4h. (1)H and (13)C NMR resonances of the pyrodextrin were assigned with the assistance of 2D techniques including COSY, TOCSY, HSQC, and HMBC, all measured on a 500MHz instrument. During dextrinization, native waxy maize starch was hydrolyzed and extensively branched with new glycosidic linkages. The resulting pyrodextrin became 100% soluble in water and produced lower viscosity solutions at 30% solids. There were only 1.2% reducing ends (α-form) detected in the pyrodextrin, but 1,6-anhydro-β-d-glucopyranosyl units accounted for 5.2% of repeating units and they were thought to be at the potential reducing end. New glycosyl linkages including α-1,6, β-1,6, α-1,2, and β-1,2 were identified. The total non-α-1,4 linkages in the pyrodextrin were about 17.8% compared to 5.8% in a maltodextrin prepared by α-amylase digestion. Transglycosidation and depolymerization occurred during dextrinization, and the resulting pyrodextrin was highly branched. PMID:27474585

  2. Discrete deexcitations in 235U from Nuclear Resonance Fluorescence

    NASA Astrophysics Data System (ADS)

    Kwan, E.; Howell, C. R.; Raut, R.; Rusev, G.; Tonchev, A. P.; Tornow, W.; Adekola, A. S.; Hammond, S. L.; Karwowski, H. J.; Pedroni, R.; Kelley, J. H.

    2010-11-01

    Systematics of the even-even rare-earth nuclei suggest a concentration of M1 excitations peaking around 3 MeV with a ∑B(M1) strength of ˜3μN^2. In addition, a linear dependence on the square of the ground-state deformation was observed in the systematics of the ∑B(M1) strengths. The actinide region is interesting for investigation of the ``scissors'' mode of M1 excitations because it has neutron-rich nuclei with large deformations. Evidence of M1 resonances concentrated around 2.0-2.5 MeV were found in ^238U & ^232Th. A research program has been initiated at TUNL to measure dipole transitions in the actinide using HIγS. Nearly monoenergic & circular polarized γ-ray beams below 3.0 MeV was used to measure transitions in ^235U. More than 20 transitions were observed. The integrated cross sections, B(M1) strengths & branching transitions intensities will be presented and compared with previous measurements.

  3. Quadrupolar effects on nuclear spins of neutral arsenic donors in silicon

    NASA Astrophysics Data System (ADS)

    Franke, David P.; Pflüger, Moritz P. D.; Mortemousque, Pierre-André; Itoh, Kohei M.; Brandt, Martin S.

    2016-04-01

    We present electrically detected electron nuclear double resonance measurements of the nuclear spins of ionized and neutral arsenic donors in strained silicon. In addition to a reduction of the hyperfine coupling, we find significant quadrupole interactions of the nuclear spin of the neutral donors of the order of 10 kHz. By comparing these to the quadrupole shifts due to crystal fields measured for the ionized donors, we identify the effect of the additional electron on the electric field gradient at the nucleus. This extra component is expected to be caused by the coupling to electric field gradients created due to changes in the electron wave function under strain.

  4. Nuclear magnetic resonance imaging and spectroscopy of human brain function.

    PubMed Central

    Shulman, R G; Blamire, A M; Rothman, D L; McCarthy, G

    1993-01-01

    The techniques of in vivo magnetic resonance (MR) imaging and spectroscopy have been established over the past two decades. Recent applications of these methods to study human brain function have become a rapidly growing area of research. The development of methods using standard MR contrast agents within the cerebral vasculature has allowed measurements of regional cerebral blood volume (rCBV), which are activity dependent. Subsequent investigations linked the MR relaxation properties of brain tissue to blood oxygenation levels which are also modulated by consumption and blood flow (rCBF). These methods have allowed mapping of brain activity in human visual and motor cortex as well as in areas of the frontal lobe involved in language. The methods have high enough spatial and temporal sensitivity to be used in individual subjects. MR spectroscopy of proton and carbon-13 nuclei has been used to measure rates of glucose transport and metabolism in the human brain. The steady-state measurements of brain glucose concentrations can be used to monitor the glycolytic flux, whereas subsequent glucose metabolism--i.e., the flux into the cerebral glutamate pool--can be used to measure tricarboxylic acid cycle flux. Under visual stimulation the concentration of lactate in the visual cortex has been shown to increase by MR spectroscopy. This increase is compatible with an increase of anaerobic glycolysis under these conditions as earlier proposed from positron emission tomography studies. It is shown how MR spectroscopy can extend this understanding of brain metabolism. Images Fig. 1 Fig. 2 Fig. 3 PMID:8475050

  5. Description of nuclear octupole and quadrupole deformation close to axial symmetry: Octupole vibrations in the X(5) nuclei {sup 150}Nd and {sup 152}Sm

    SciTech Connect

    Bizzeti, P. G.; Bizzeti-Sona, A. M.

    2010-03-15

    The model, introduced in a previous paper, for the description of the octupole and quadrupole degrees of freedom in conditions close to the axial symmetry is used to describe the negative-parity band based on the first octupole vibrational state in nuclei close to the critical point of the U(5)-to-SU(3) phase transition. The situation of {sup 150}Nd and {sup 152}Sm is discussed in detail. The positive-parity levels of these nuclei, and also the in-band E2 transitions, are reasonably accounted for by the X(5) model. With simple assumptions on the nature of the octupole vibrations, it is also possible to describe the negative-parity sector with comparable accuracy without changing the description of the positive-parity part.

  6. Effective temperature of amorphous carbon studied using nuclear-resonance photon scattering

    NASA Astrophysics Data System (ADS)

    Moreh, R.; Beck, O.; Jäger, D.; Finkelstein, Y.; Kneissl, U.; Margraf, J.; Maser, H.; Pitz, H. H.

    1997-07-01

    The effective temperature of isotopic amorphous carbon (13C) was measured, at 295 K, by employing the nuclear resonance photon scattering (NRPS) technique. The photon beam was in the form of bremsstrahlung obtained from an electron beam of the Stuttgart Dynamitron, with E=4.1 MeV, and the resonance scattering from the 3089-keV and the 3684-keV levels in 13C was measured. The effective temperature of 13C was found to be (822+/-123) K, which is higher by about 13% than that calculated from the experimental vibrational density of states of amorphous carbon. This deviation is discussed.

  7. Nuclear magnetic resonance studies of liquids morphology inside partially saturated porous media

    NASA Astrophysics Data System (ADS)

    Nechifor, Ruben; Badea, Codruta; Ardelean, Ioan

    2009-08-01

    In the present contribution we are investigating the relationship between liquid morphology and relaxation time distribution in partially saturated pores. The filling fluids are acetone (polar) and tetradecane (nonpolar). The porous sample is a silica glass (Vitrapor#5) with the nominal mean pore size is d = 1 μm (± 0.6 μm). All nuclear magnetic resonance relaxation experiments are performed at 20C using a NMR instrument operable at 20 MHz proton resonance frequency. The experimental results are compared with a two phase exchange model providing us information on the strength of surface relaxation.

  8. 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.

  9. High sensitivity nuclear magnetic resonance probe for anvil cell pressure experiments.

    PubMed

    Haase, Jürgen; Goh, Swee K; Meissner, Thomas; Alireza, Patricia L; Rybicki, Damian

    2009-07-01

    While the highest pressures can be achieved with diamond anvil cells, limited sample size and anvil geometry have hampered their application in nuclear magnetic resonance (NMR) experiments due to weak signal-to-noise. Here we report a new probe design that is based on having the resonant radio frequency coil that encloses the sample within the anvil cell inside the gasket hole. This increases the filling factor tremendously and results in greatly enhanced NMR sensitivity. The setup is described together with room temperature Na and Al NMR experiments. PMID:19655963

  10. Friction in nuclear dynamics

    SciTech Connect

    Swiatecki, W.J.

    1985-03-01

    The problem of dissipation in nuclear dynamics is related to the breaking down of nuclear symmetries and the transition from ordered to chaotic nucleonic motions. In the two extreme idealizations of the perfectly Ordered Regime and the fully Chaotic Regime, the nucleus should behave as an elastic solid or an overdamped fluid, respectively. In the intermediate regime a complicated visco-elastic behaviour is expected. The discussion is illustrated by a simple estimate of the frequency of the giant quadrupole resonance in the Ordered Regime and by applications of the wall and window dissipation formulae in the Chaotic Regime. 51 refs.

  11. Identification and fragmentation pathways of caffeine metabolites in urine samples via liquid chromatography with positive electrospray ionization coupled to a hybrid quadrupole linear ion trap (LTQ) and Fourier transform ion cyclotron resonance mass spectrometry and tandem mass spectrometry.

    PubMed

    Bianco, Giuliana; Abate, Salvatore; Labella, Cristiana; Cataldi, Tommaso R I

    2009-04-01

    Liquid chromatography (LC) with positive ion electrospray ionization (ESI+) coupled to a hybrid quadrupole linear ion trap (LTQ) and Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS) was employed for the simultaneous determination of caffeine and its metabolites in human urine within a single chromatographic run. LC/ESI-FTICRMS led to the unambiguous determination of the molecular masses of the studied compounds without interference from other biomolecules. A systematic and comprehensive study of the mass spectral behaviour of caffeine and its fourteen metabolites by tandem mass spectrometry (MS/MS) was performed, through in-source ion trap collision-induced dissociation (CID) of the protonated molecules, [M+H](+). A retro-Diels-Alder (RDA) process along with ring-contraction reactions were the major fragmentation pathways observed during CID. The base peak of xanthine precursors originates from the loss of methyl isocyanate (CH(3)NCO, 57 Da) or isocyanic acid (HNCO, 43 Da), which in turn lose a CO unit. Also uric acid derivatives shared a RDA rearrangement as a common fragmentation process and a successive loss of CO(2) or CO. The uracil derivatives showed a loss of a ketene unit (CH(2)CO, 42 Da) from the protonated molecule along with the loss of H(2)O or CO. To assess the potential of the present method three established metabolite ratios to measure P450 CYP1A2, N-acetyltransferase and xanthine oxidase activities were evaluated by a number of identified metabolites from healthy human urine samples after caffeine intake. PMID:19260028

  12. Variable Permanent Magnet Quadrupole

    SciTech Connect

    Mihara, T.; Iwashita, Y.; Kumada, M.; Spencer, C.M.; /SLAC

    2007-05-23

    A permanent magnet quadrupole (PMQ) is one of the candidates for the final focus lens in a linear collider. An over 120 T/m strong variable permanent magnet quadrupole is achieved by the introduction of saturated iron and a 'double ring structure'. A fabricated PMQ achieved 24 T integrated gradient with 20 mm bore diameter, 100 mm magnet diameter and 20 cm pole length. The strength of the PMQ is adjustable in 1.4 T steps, due to its 'double ring structure': the PMQ is split into two nested rings; the outer ring is sliced along the beam line into four parts and is rotated to change the strength. This paper describes the variable PMQ from fabrication to recent adjustments.

  13. New Resolved Resonance Region Evaluation for 63Cu and 65Cu for Nuclear Criticality Safety Program

    SciTech Connect

    Sobes, Vladimir; Leal, Luiz C; Guber, Klaus H; Forget, Benoit; Kopecky, S.; Schillebeeckx, P.; Siegler, P.

    2014-01-01

    A new resolved resonance region evaluation of 63Cu and 65Cu was done in the energy region from 10-5 eV to 99.5 keV. The R-Matrix SAMMY method using the Reich-Moore approximation was used to create a new set of consistent resonance parameters. The new evaluation was based on three experimental transmission data sets; two measured at ORELA and one from MITR, and two radiative capture experimental data sets from GELINA. A total of 141 new resonances were identied for 63Cu and 117 for 65Cu. The corresponding set of external resonances for each isotope was based on the identied resonances above 99.5 keV from the ORELA transmission data. The negative external levels (bound levels) were determined to match the dierential thermal cross section measured at the MITR. Double dierential elastic scattering cross sections were calculated from the new set of resonance parameters. Benchmarking calculations were carried out on a set of ICSBEP benchmarks. This work is in support of the DOE Nuclear Criticality Safety Program.

  14. Scientific opportunities in nuclear resonance spectroscopy from source-driven revolution

    NASA Astrophysics Data System (ADS)

    Shenoy, G. K.; Röhlsberger, R.

    2008-02-01

    From the beginning of its discovery the Mössbauer effect has continued to be one of the most powerful tools with broad applications in diverse areas of science and technology. With the advent of synchrotron radiation sources such as the Advanced Photon Source (APS), the European Synchrotron Radiation Facility (ESRF) and the Super Photon Ring-8 (SPring-8), the tool has enlarged its scope and delivered new capabilities. The popular techniques most generally used in the field of materials physics, chemical physics, geoscience, and biology are hyperfine spectroscopy via elastic nuclear forward scattering (NFS), vibrational spectroscopy via nuclear inelastic scattering (NRIXS), and, to a lesser extent, diffusional dynamics from quasielastic nuclear forward scattering (QNFS). As we look ahead, new storage rings with enhanced brilliance such as PETRA-III under construction at DESY, Hamburg, and PEP-III in its early design stage at SLAC, Stanford, will provide new and unique science opportunities. In the next two decades, x-ray free-electron lasers (XFELs), based both on self-amplified spontaneous emission (SASE-XFELs) and a seed (SXFELs), with unique time structure, coherence and a five to six orders higher average brilliance will truly revolutionize nuclear resonance applications in a major way. This overview is intended to briefly address the unique radiation characteristics of new sources on the horizon and to provide a glimpse of scientific prospects and dreams in the nuclear resonance field from the new radiation sources. We anticipate an expanded nuclear resonance research activity with applications such as spin and phonon mapping of a single nanostructure and their assemblies, interfaces, and surfaces; spin dynamics; nonequilibrium dynamics; photochemical reactions; excited-state spectroscopy; and nonlinear phenomena.

  15. Scientific opportunities in nuclear resonance spectroscopy from source-driven revolution.

    SciTech Connect

    Shenoy, G. K.; Rohlsberger, R.; X-Ray Science Division; DESY

    2008-02-01

    From the beginning of its discovery the Moessbauer effect has continued to be one of the most powerful tools with broad applications in diverse areas of science and technology. With the advent of synchrotron radiation sources such as the Advanced Photon Source (APS), the European Synchrotron Radiation Facility (ESRF) and the Super Photon Ring-8 (SPring-8), the tool has enlarged its scope and delivered new capabilities. The popular techniques most generally used in the field of materials physics, chemical physics, geoscience, and biology are hyperfine spectroscopy via elastic nuclear forward scattering (NFS), vibrational spectroscopy via nuclear inelastic scattering (NRIXS), and, to a lesser extent, diffusional dynamics from quasielastic nuclear forward scattering (QNFS). As we look ahead, new storage rings with enhanced brilliance such as PETRA-III under construction at DESY, Hamburg, and PEP-III in its early design stage at SLAC, Stanford, will provide new and unique science opportunities. In the next two decades, x-ray free-electron lasers (XFELs), based both on self-amplified spontaneous emission (SASE-XFELs) and a seed (SXFELs), with unique time structure, coherence and a five to six orders higher average brilliance will truly revolutionize nuclear resonance applications in a major way. This overview is intended to briefly address the unique radiation characteristics of new sources on the horizon and to provide a glimpse of scientific prospects and dreams in the nuclear resonance field from the new radiation sources. We anticipate an expanded nuclear resonance research activity with applications such as spin and phonon mapping of a single nanostructure and their assemblies, interfaces, and surfaces; spin dynamics; nonequilibrium dynamics; photochemical reactions; excited-state spectroscopy; and nonlinear phenomena.

  16. Linac quadrupole connections

    SciTech Connect

    Stiening, R.

    1984-07-12

    Linac type QC and QCH quadrupoles are mounted on the accelerator with their power connection side facing the injector. The connections are on the top of the magnet. The correct polarity for magnets is shown. The magnetic centers of all magnets are measured. If the magnetic center is above the geometric center, the distance delta y is positive. If the magnetic center is to the right of the geometric center, the distance delta x is positive.

  17. Nuclear Resonance Fluorescence Measurements on ^237Np for Security and Safeguards Applications

    NASA Astrophysics Data System (ADS)

    Angell, C. T.; Joshi, T.; Yee, Ryan; Norman, E. B.; Kulp, W. D.; Warren, G. A.; Korbly, S.; Klimenko, A.; Wilson, C.; Copping, R.; Shuh, D. K.

    2009-10-01

    The smuggling of nuclear material and the diversion of fissile material for covert weapon programs both present grave risks to world security. Methods are needed to detect nuclear material smuggled in cargo, and for proper material accountability in civilian fuel re-processing facilities. Nuclear resonance fluorescence (NRF) is a technique that can address both needs. It is a non-destructive active interrogation method that provides isotope-specific information. It works by using a γ-ray beam to resonantly excite levels in a nucleus and observing the γ-rays emitted whose energy and intensity are characteristic of that isotope. ^237Np presents significant safeguard challenges; it is fissile yet currently has fewer safeguard restrictions. NRF measurements on ^237Np will expand the nuclear database and will permit designing interrogation and assay systems. Measurements were made using the bremsstrahlung beam at the HVRL at MIT on a 7 g target of ^237Np with two incident electron energies of 2.8 and 3.1 MeV. Results will be presented with discussion of the relevant nuclear structure necessary to predict levels in other actinides.

  18. High Repetition Rate, LINAC-based Nuclear Resonance Fluorescence FY 2009 Final Report

    SciTech Connect

    Mathew Kinlaw; Scott Watson; James Johnson; Alan Hunt; Heather Seipel; Edward Reedy

    2009-10-01

    Nuclear Resonance Fluorescence (NRF), which is possible for nuclei with atomic numbers greater than helium (Z=2), occurs when a nuclear level is excited by resonant absorption of a photon and subsequently decays by reemission of a photon. The excited nuclear states can become readily populated, provided the incident photon’s energy is within the Doppler-broadened width of the energy level being excited. Utilizing continuous energy photon spectra, as is characteristic of a bremsstrahlung photon beam, as the inspection source, ensures that at least some fraction of the impinging beam will contribute to the population of the excited energy levels in the material of interest. Upon de-excitation, either to the ground state or to a lower-energy excited state, the emitted fluorescence photon’s energy will correspond to the energy difference between the excited state and the state to which it decays. As each isotope inherently contains unique nuclear energy levels, the NRF states for each isotope are also unique. By exploiting this phenomenon, NRF photon detection provides a well-defined signature for identifying the presence of individual nuclear species. This report summarizes the second year (Fiscal Year [FY] 2009) of a collaborative research effort between Idaho National Laboratory, Idaho State University’s Idaho Accelerator Center, and Pacific Northwest National Laboratory. This effort focused on continuing to assess and optimize NRF-based detection techniques utilizing a slightly modified, commercially available, pulsed medical electron accelerator.

  19. Billion-fold enhancement in sensitivity of nuclear magnetic resonance spectroscopy for magnesium ions in solution.

    PubMed

    Gottberg, Alexander; Stachura, Monika; Kowalska, Magdalena; Bissell, Mark L; Arcisauskaite, Vaida; Blaum, Klaus; Helmke, Alexander; Johnston, Karl; Kreim, Kim; Larsen, Flemming H; Neugart, Rainer; Neyens, Gerda; Garcia Ruiz, Ronald F; Szunyogh, Daniel; Thulstrup, Peter W; Yordanov, Deyan T; Hemmingsen, Lars

    2014-12-15

    β-nuclear magnetic resonance (NMR) spectroscopy is highly sensitive compared to conventional NMR spectroscopy, and may be applied for several elements across the periodic table. β-NMR has previously been successfully applied in the fields of nuclear and solid-state physics. In this work, β-NMR is applied, for the first time, to record an NMR spectrum for a species in solution. (31)Mg β-NMR spectra are measured for as few as 10(7) magnesium ions in ionic liquid (EMIM-Ac) within minutes, as a prototypical test case. Resonances are observed at 3882.9 and 3887.2 kHz in an external field of 0.3 T. The key achievement of the current work is to demonstrate that β-NMR is applicable for the analysis of species in solution, and thus represents a novel spectroscopic technique for use in general chemistry and potentially in biochemistry.

  20. Billion-fold enhancement in sensitivity of nuclear magnetic resonance spectroscopy for magnesium ions in solution.

    PubMed

    Gottberg, Alexander; Stachura, Monika; Kowalska, Magdalena; Bissell, Mark L; Arcisauskaite, Vaida; Blaum, Klaus; Helmke, Alexander; Johnston, Karl; Kreim, Kim; Larsen, Flemming H; Neugart, Rainer; Neyens, Gerda; Garcia Ruiz, Ronald F; Szunyogh, Daniel; Thulstrup, Peter W; Yordanov, Deyan T; Hemmingsen, Lars

    2014-12-15

    β-nuclear magnetic resonance (NMR) spectroscopy is highly sensitive compared to conventional NMR spectroscopy, and may be applied for several elements across the periodic table. β-NMR has previously been successfully applied in the fields of nuclear and solid-state physics. In this work, β-NMR is applied, for the first time, to record an NMR spectrum for a species in solution. (31)Mg β-NMR spectra are measured for as few as 10(7) magnesium ions in ionic liquid (EMIM-Ac) within minutes, as a prototypical test case. Resonances are observed at 3882.9 and 3887.2 kHz in an external field of 0.3 T. The key achievement of the current work is to demonstrate that β-NMR is applicable for the analysis of species in solution, and thus represents a novel spectroscopic technique for use in general chemistry and potentially in biochemistry. PMID:25303164

  1. Key metabolites in tissue extracts of Elliptio complanata identified using (1)H nuclear magnetic resonance spectroscopy.

    PubMed

    Hurley-Sanders, Jennifer L; Levine, Jay F; Nelson, Stacy A C; Law, J M; Showers, William J; Stoskopf, Michael K

    2015-01-01

    We used (1)H nuclear magnetic resonance spectroscopy to describe key metabolites of the polar metabolome of the freshwater mussel, Elliptio complanata. Principal components analysis documented variability across tissue types and river of origin in mussels collected from two rivers in North Carolina (USA). Muscle, digestive gland, mantle and gill tissues yielded identifiable but overlapping metabolic profiles. Variation in digestive gland metabolic profiles between the two mussel collection sites was characterized by differences in mono- and disaccharides. Variation in mantle tissue metabolomes appeared to be associated with sex. Nuclear magnetic resonance spectroscopy is a sensitive means to detect metabolites in the tissues of E. complanata and holds promise as a tool for the investigation of freshwater mussel health and physiology.

  2. Protein carbon-13 spin systems by a single two-dimensional nuclear magnetic resonance experiment

    SciTech Connect

    Oh, B.H.; Westler, W.M.; Darba, P.; Markley, J.L.

    1988-05-13

    By applying a two-dimensional double-quantum carbon-13 nuclear magnetic resonance experiment to a protein uniformly enriched to 26% carbon-13, networks of directly bonded carbon atoms were identified by virtue of their one-bond spin-spin couplings and were classified by amino acid type according to their particular single- and double-quantum chemical shift patterns. Spin systems of 75 of the 98 amino acid residues in a protein, oxidized Anabaena 7120 ferredoxin (molecular weight 11,000), were identified by this approach, which represents a key step in an improved methodology for assigning protein nuclear magnetic resonance spectra. Missing spin systems corresponded primarily to residues located adjacent to the paramagnetic iron-sulfur cluster. 25 references, 2 figures.

  3. Analysis of antimycin A by reversed-phase liquid chromatography/nuclear magnetic-resonance spectrometry

    USGS Publications Warehouse

    Ha, Steven T.K.; Wilkins, Charles L.; Abidi, Sharon L.

    1989-01-01

    A mixture of closely related streptomyces fermentation products, antimycin A, Is separated, and the components are identified by using reversed-phase high-performance liquid chromatography with directly linked 400-MHz proton nuclear magnetic resonance detection. Analyses of mixtures of three amino acids, alanine, glycine, and valine, are used to determine optimal measurement conditions. Sensitivity increases of as much as a factor of 3 are achieved, at the expense of some loss in chromatographic resolution, by use of an 80-μL NMR cell, Instead of a smaller 14-μL cell. Analysis of the antimycin A mixture, using the optimal analytical high performance liquid chromatography/nuclear magnetic resonance conditions, reveals it to consist of at least 10 closely related components.

  4. Key metabolites in tissue extracts of Elliptio complanata identified using 1H nuclear magnetic resonance spectroscopy

    PubMed Central

    Hurley-Sanders, Jennifer L.; Levine, Jay F.; Nelson, Stacy A. C.; Law, J. M.; Showers, William J.; Stoskopf, Michael K.

    2015-01-01

    We used 1H nuclear magnetic resonance spectroscopy to describe key metabolites of the polar metabolome of the freshwater mussel, Elliptio complanata. Principal components analysis documented variability across tissue types and river of origin in mussels collected from two rivers in North Carolina (USA). Muscle, digestive gland, mantle and gill tissues yielded identifiable but overlapping metabolic profiles. Variation in digestive gland metabolic profiles between the two mussel collection sites was characterized by differences in mono- and disaccharides. Variation in mantle tissue metabolomes appeared to be associated with sex. Nuclear magnetic resonance spectroscopy is a sensitive means to detect metabolites in the tissues of E. complanata and holds promise as a tool for the investigation of freshwater mussel health and physiology. PMID:27293708

  5. Controlling nuclear spin exchange via optical Feshbach resonances in Y171b

    NASA Astrophysics Data System (ADS)

    Reichenbach, Iris; Julienne, Paul S.; Deutsch, Ivan H.

    2009-08-01

    Nuclear spin exchange occurs in ultracold collisions of fermionic alkaline-earth-metal-like atoms due to a difference between s - and p -wave phase shifts. We study the use of an optical Feshbach resonance, excited on the S10→P31 intercombination line of Y171b , to affect a large modification of the s -wave scattering phase shift and thereby optically mediate nuclear exchange forces. We perform a full multichannel calculation of the photoassociation resonances and wave functions and from these calculate the real and imaginary parts of the scattering length. As a figure of merit of this interaction, we estimate the fidelity to implement a SWAP entangling quantum logic gate for two atoms trapped in the same well of an optical lattice. For moderate parameters one can achieve a gate fidelity of ˜95% in a time of ˜50μs .

  6. Negotiated identities of chemical instrumentation: the case of nuclear magnetic resonance spectroscopy, 1956-1969.

    PubMed

    Roberts, Jody A

    2003-05-01

    What is an NMR spectrometer? Beginning with this seemingly simple question, I will explore the development of nuclear magnetic resonance spectroscopy between the years 1956 and 1969 from two vantage points: the organic chemists who used the new instrument, and Varian Associates-the makers of the first NMR spectrometers-. Through an examination of the articles and advertisements published in the Journal of Organic Chemistry, I will draw two conclusions. First, organic chemists and Varian Associates (along with other actors) are co-responsible for the development of nuclear magnetic resonance spectroscopy (i.e., NMR spectroscopy was not created by a single actor). Second, by changing the way NMR spectrometers are used, organic chemists attempted to change to the identity of the instrument. Similarly, when Varian Associates advertised their NMR spectrometers in a different way, they, too, attempted to change the identity of the instrument.

  7. Nuclear Magnetic Resonance (NMR) analysis of a Kel-F resin and lacquer

    NASA Astrophysics Data System (ADS)

    Rutenberg, A. C.

    1985-08-01

    Proton, carbon, and fluorine nuclear magnetic resonance (NMR) spectroscopy has been used at the Oak Ridge Y-12 Plant to determine the concentration of various species present in Kel-F 800 resin and its lacquers. Nuclear magnetic resonance (NMR) spectroscopy has been used to characterize Kel-F 800 resin and to measure the various chemical species present in a lacquer based on this resin. Proton NMR spectroscopy was used to measure the ratio of ethyl acetate to xylenes and to estimate the vinylidene fluoride content of the resin. Fluorine NMR spectroscopy was used to determine the water and ethanol content of the lacquer as well as some of its components. Fluorine NMR spectroscopy was also used to estimate the amount of perfluorodecanoate emulsifier present in the Kel-F resin. Carbon-13 NMR spectroscopy was used to determine the isomeric composition of various batches of xylenes and as an alternate method for measuring the vinylidene fluoride content of the resin.

  8. Stimulated echoes and two-dimensional nuclear magnetic resonance spectra for solids with simple line shapes

    NASA Astrophysics Data System (ADS)

    Geil, Burkhard; Diezemann, Gregor; Böhmer, Roland

    2008-03-01

    Nuclear magnetic resonance (NMR) experiments on ion conductors often yield rather unstructured spectra, which are hard to interpret if the relation between the actual translational motion of the mobile species and the changes of the NMR frequencies is not known. In order to facilitate a general analysis of experiments on solids with such spectra, different models for the stochastic evolution of the NMR frequencies are considered. The treated models involve random frequency jumps, diffusive evolutions, or approximately fixed frequency jumps. Two-dimensional nuclear magnetic resonance spectra as well as stimulated-echo functions for the study of slow and ultraslow translational dynamics are calculated for Gaussian equilibrium line shapes. The results are compared with corresponding ones from rotational models and with experimental data.

  9. Nuclear magnetic resonance spectroscopy is highly sensitive for lipid-soluble metabolites.

    PubMed

    Dai, Haiyang; Hong, Bikai; Xu, Zhifeng; Ma, Lian; Chen, Yaowen; Xiao, Yeyu; Wu, Renhua

    2013-08-01

    Although the water-soluble metabolite profile of human mesenchymal stem cells is known, the lipid profile still needs further investigation. In this study, methanol-chloroform was used to extract pid-soluble metabolites and perchloric acid was used to extract water-soluble metabolites. Furthermore, a dual phase extraction method using methanol-chloroform and water was used to obtain both water and lipid fractions simultaneously. All metabolite extractions were analyzed on a 9.4T high-resolution nuclear magnetic resonance spectrometer. Metabolite resonance peaks were assigned in the acquired spectra according to the chemical shift, and the extraction efficiency of ferent methods was compared. Results showed that in the spectra of water-soluble extracts, major metabolites comprised low molecular weight metabolites, including lactate, acetic acid, fatty acids, threonine, glutamic acid, creatine, choline and its derivatives, while in the spectra of lipid-soluble extracts, most metabolites were assigned to fatty acids. Among the different extraction procedures, perchloric acid was more efficient in extracting water-soluble metabolites and methanol-chloroform was efficient in extracting organic components compared with the dual phase extraction method. Nuclear magnetic resonance spectroscopy showed that as low as 0.7 mg organic yield was enough to obtain clear resonance peaks, while about 6.0 mg water-soluble yield was needed to obtain relatively favorable spectral lines. These results show that the efficiency of extracting water and lipid fractions is higher using perchloric acid and methanol-chloroform compared with dual phase extraction and that nuclear magnetic resonance spectroscopy is highly sensitive for analyzing lipid-soluble extracts.

  10. Classification of iron-sulfur cores in ferredoxins by 1H nuclear magnetic resonance spectroscopy.

    PubMed

    Nagayama, K; Ozaki, Y; Kyogoku, Y; Hase, T; Matsubara, H

    1983-09-01

    A 1H nuclear magnetic resonance (NMR) study was carried out on various ferredoxins which possess one of three types of iron-sulfur clusters, (2Fe-2S), (3Fe-3S), or (4Fe-4S). In the isolated form, (2Fe-2S) ferredoxins from spinach (Spinacea oleracia), pokeweed (Phytolacca americana), a blue-green alga (Spirulina platensis), and a halobacterium (Halobacterium halobium) exhibited two broad resonances common in chemical shift at the region downfield of 10 ppm. In their reduced forms, seven contact-shifted resonances appeared spread over 30 ppm. Although the positions of the contact-shifted resonances in the reduced state differed among the four, a common trend in the temperature dependence of their resonance positions was recognized. Two (4Fe-4S) ferredoxins from Bacillus stearothermophilus and Bacillus thermoproteolyticus exhibited almost indistinguishable spectral patterns in both the oxidized and reduced forms. The ferricyanide-treated ferredoxins of B. stearothermophilus and B. thermoproteolyticus showed characteristic contact-shifted resonances distinct from the spectra of the original (4Fe-4S) ferredoxins. This corresponds to the recent finding of the interconversion of (4Fe-4S) and (3Fe-3S) clusters with ferricyanide in the ferredoxin. Based on our data together with reported NMR data on other ferredoxins, contact-shift resonances of three types of clusters were tabulated. The reliability of NMR classification increases when we compare the NMR spectra of a ferredoxin with the classification standards at the two redox states. Moreover, not only the absolute values of the chemical shifts of contact-shifted resonances but also their temperature dependence give distinctive information applicable to iron core identification.

  11. Fetal imaging by nuclear magnetic resonance: a study in goats: work in progress

    SciTech Connect

    Foster, M.A.; Knight, C.H.; Rimmington, J.E.; Mallard, J.R.

    1983-10-01

    Nuclear magnetic resonance proton imaging was used to obtain images of goat fetuses in utero. The long T1 relaxation time of amniotic fluid makes it appear black on proton density images when examined using the Aberdeen imager, and so allows very good discrimination of the position and structure of the fetus. Some fetal internal tissues can be seen on T1 images. These findings suggest that NMR imaging has great potential in pregnancy studies.

  12. Nuclear magnetic resonance studies of granular flows: Technical progress report, quarter ending 09/30/93

    SciTech Connect

    Not Available

    1993-10-27

    This Technical Progress Report for the quarter ending 09/30/93 describes work on two tasks which are part of nuclear magnetic resonance studies of granular flows. (1) Research has been directed toward improving concentration measurements under reasonably fast conditions. (2) The process continues of obtaining comprehensive velocity, concentration, and diffusion information at several angular velocities of the cylinder for seeds (mustard, sesame, and sunflower seeds) flowing in a half-filled cylinder.

  13. Nuclear magnetic resonance at millitesla fields using a zero-field spectrometer.

    PubMed

    Tayler, Michael C D; Sjolander, Tobias F; Pines, Alexander; Budker, Dmitry

    2016-09-01

    We describe new analytical capabilities for nuclear magnetic resonance (NMR) experiments in which signal detection is performed with chemical resolution (via spin-spin J couplings) in the zero to ultra-low magnetic field region, below 1μT. Using magnetic fields in the 100μT to 1mT range, we demonstrate the implementation of conventional NMR pulse sequences with spin-species selectivity.

  14. Fissile and Non-Fissile Material Detection Using Nuclear Acoustic Resonance Signatures

    SciTech Connect

    Bernhard R. Tittmann; P.M. Lenahan; David Spears; Rhys Williams

    2008-11-25

    The objective of this project is to develop anovel technique for remote, non-destructive, non-radiation-based detection of materials of interest to Nonproliferation Programs. We propse the development of a detection system based on magnetic resonance principles (NAR), which would work where radiation detection is not possible. The approach would be non-intrusive, penetrating, applicable to many materials of interest for Nonproliferation, and be able to identify the nuclear samples under investigation.

  15. Nuclear magnetic resonance at millitesla fields using a zero-field spectrometer

    NASA Astrophysics Data System (ADS)

    Tayler, Michael C. D.; Sjolander, Tobias F.; Pines, Alexander; Budker, Dmitry

    2016-09-01

    We describe new analytical capabilities for nuclear magnetic resonance (NMR) experiments in which signal detection is performed with chemical resolution (via spin-spin J couplings) in the zero to ultra-low magnetic field region, below 1 μT. Using magnetic fields in the 100 μT to 1 mT range, we demonstrate the implementation of conventional NMR pulse sequences with spin-species selectivity.

  16. 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.

  17. Robert Vivian Pound and the Discovery of Nuclear Magnetic Resonance in Condensed Matter

    NASA Astrophysics Data System (ADS)

    Pavlish, Ursula

    2010-06-01

    This paper is based upon five interviews I conducted with Robert Vivian Pound in 2006-2007 and covers his childhood interest in radios, his time at the Massachusetts Institute of Technology Radiation Laboratory during the Second World War, his work on the discovery of nuclear magnetic resonance in condensed matter, his travels as a professor at Harvard University, and his social interactions with other physicists.

  18. Theory and applications of maps on SO(3) in nuclear magnetic resonance

    SciTech Connect

    Cho, H.M.

    1987-02-01

    Theoretical approaches and experimental work in the design of multiple pulse sequences in Nuclear Magnetic Resonance (NMR) are the subjects of this dissertation. Sequences of discrete pulses which reproduce the nominal effect of single pulses, but over substantially broader, narrower, or more selective ranges of transition frequencies, radiofrequency field amplitudes, and spin-spin couplings than the single pulses they replace, are developed and demonstrated. 107 refs., 86 figs., 6 tabs.

  19. 27Al magic-angle spinning nuclear magnetic resonance satellite transition spectroscopy of glasses in the system K2O-Al2O3-SiO2.

    PubMed

    Mundus, C; Müller-Warmuth, W

    1995-10-01

    27Al magic-angle spinning nuclear magnetic resonance satellite transition spectroscopy at 78 MHz has been applied to determine (true) chemical shift and quadrupole coupling parameters of glasses in the system K2O-Al2O3-SiO2 with 60-80 mol% SiO2 and K2O concentrations between 0 and 24 mol%. The powdered crystalline aluminosilicates andalusite and sillimanite have also been examined. In the glasses, all Al appears to be tetrahedrally bound in the aluminosilicate network unless x = mol% K2O:mol% Al2O3 becomes extremely small. Upon decreasing x the distortion of the tetrahedral Al(OSi)4 units increases in steps, and possible explanations are discussed. Six-coordinated aluminum observed for x < 0.2 is connected with the occurrence of interstitial Al3+ ions which charge-compensate the AlO4 units in addition to K+. PMID:8748646

  20. Resonance-inclined optical nuclear spin polarization of liquids in diamond structures

    NASA Astrophysics Data System (ADS)

    Chen, Q.; Schwarz, I.; Jelezko, F.; Retzker, A.; Plenio, M. B.

    2016-02-01

    Dynamic nuclear polarization (DNP) of molecules in a solution at room temperature has the potential to revolutionize nuclear magnetic resonance spectroscopy and imaging. The prevalent methods for achieving DNP in solutions are typically most effective in the regime of small interaction correlation times between the electron and nuclear spins, limiting the size of accessible molecules. To solve this limitation, we design a mechanism for DNP in the liquid phase that is applicable for large interaction correlation times. Importantly, while this mechanism makes use of a resonance condition similar to solid-state DNP, the polarization transfer is robust to a relatively large detuning from the resonance due to molecular motion. We combine this scheme with optically polarized nitrogen-vacancy (NV) center spins in nanodiamonds to design a setup that employs optical pumping and is therefore not limited by room temperature electron thermal polarization. We illustrate numerically the effectiveness of the model in a flow cell containing nanodiamonds immobilized in a hydrogel, polarizing flowing water molecules 4700-fold above thermal polarization in a magnetic field of 0.35 T, in volumes detectable by current NMR scanners.

  1. Enhanced affinity of ketotifen toward tamarind seed polysaccharide in comparison with hydroxyethylcellulose and hyaluronic acid: a nuclear magnetic resonance investigation.

    PubMed

    Uccello-Barretta, Gloria; Nazzi, Samuele; Balzano, Federica; Di Colo, Giacomo; Zambito, Ylenia; Zaino, Chiara; Sansò, Marco; Salvadori, Eleonora; Benvenuti, Marco

    2008-08-01

    Nuclear magnetic resonance (NMR) spectroscopy demonstrated that, in aqueous solution, ketotifen fumarate bound more strongly to tamarind seed polysaccharide (TSP) than to hydroxyethylcellulose or hyaluronic acid. Results were confirmed by dynamic dialysis technique.

  2. Time differentiated nuclear resonance spectroscopy coupled with pulsed laser heating in diamond anvil cells.

    PubMed

    Kupenko, I; Strohm, C; McCammon, C; Cerantola, V; Glazyrin, K; Petitgirard, S; Vasiukov, D; Aprilis, G; Chumakov, A I; Rüffer, R; Dubrovinsky, L

    2015-11-01

    Developments in pulsed laser heating applied to nuclear resonance techniques are presented together with their applications to studies of geophysically relevant materials. Continuous laser heating in diamond anvil cells is a widely used method to generate extreme temperatures at static high pressure conditions in order to study the structure and properties of materials found in deep planetary interiors. The pulsed laser heating technique has advantages over continuous heating, including prevention of the spreading of heated sample and/or the pressure medium and, thus, a better stability of the heating process. Time differentiated data acquisition coupled with pulsed laser heating in diamond anvil cells was successfully tested at the Nuclear Resonance beamline (ID18) of the European Synchrotron Radiation Facility. We show examples applying the method to investigation of an assemblage containing ε-Fe, FeO, and Fe3C using synchrotron Mössbauer source spectroscopy, FeCO3 using nuclear inelastic scattering, and Fe2O3 using nuclear forward scattering. These examples demonstrate the applicability of pulsed laser heating in diamond anvil cells to spectroscopic techniques with long data acquisition times, because it enables stable pulsed heating with data collection at specific time intervals that are synchronized with laser pulses. PMID:26628151

  3. Time differentiated nuclear resonance spectroscopy coupled with pulsed laser heating in diamond anvil cells

    SciTech Connect

    Kupenko, I. Strohm, C.; McCammon, C.; Cerantola, V.; Petitgirard, S.; Dubrovinsky, L.; Glazyrin, K.; Vasiukov, D.; Aprilis, G.; Chumakov, A. I.; Rüffer, R.

    2015-11-15

    Developments in pulsed laser heating applied to nuclear resonance techniques are presented together with their applications to studies of geophysically relevant materials. Continuous laser heating in diamond anvil cells is a widely used method to generate extreme temperatures at static high pressure conditions in order to study the structure and properties of materials found in deep planetary interiors. The pulsed laser heating technique has advantages over continuous heating, including prevention of the spreading of heated sample and/or the pressure medium and, thus, a better stability of the heating process. Time differentiated data acquisition coupled with pulsed laser heating in diamond anvil cells was successfully tested at the Nuclear Resonance beamline (ID18) of the European Synchrotron Radiation Facility. We show examples applying the method to investigation of an assemblage containing ε-Fe, FeO, and Fe{sub 3}C using synchrotron Mössbauer source spectroscopy, FeCO{sub 3} using nuclear inelastic scattering, and Fe{sub 2}O{sub 3} using nuclear forward scattering. These examples demonstrate the applicability of pulsed laser heating in diamond anvil cells to spectroscopic techniques with long data acquisition times, because it enables stable pulsed heating with data collection at specific time intervals that are synchronized with laser pulses.

  4. Bioengineered Magnetoferritin Nanoprobes for Single-Dose Nuclear-Magnetic Resonance Tumor Imaging.

    PubMed

    Zhao, Yanzhao; Liang, Minmin; Li, Xiao; Fan, Kelong; Xiao, Jie; Li, Yanli; Shi, Hongcheng; Wang, Fei; Choi, Hak Soo; Cheng, Dengfeng; Yan, Xiyun

    2016-04-26

    Despite all the advances in multimodal imaging, it remains a significant challenge to acquire both magnetic resonance and nuclear imaging in a single dose because of the enormous difference in sensitivity. Indeed, nuclear imaging is almost 10(6)-fold more sensitive than magnetic resonance imaging (MRI); thus, repeated injections are generally required to obtain sufficient MR signals after nuclear imaging. Here, we show that strategically engineered magnetoferritin nanoprobes can image tumors with high sensitivity and specificity using SPECT and MRI in living mice after a single intravenous injection. The magnetoferritin nanoprobes composed of (125)I radionuclide-conjugated human H-ferritin iron nanocages ((125)I-M-HFn) internalize robustly into cancer cells via a novel tumor-specific HFn-TfR1 pathway. In particular, the endocytic recycling characteristic of TfR1 transporters solves the nuclear signal blocking issue caused by the high dose nanoprobes injected for MRI, thus enabling simultaneous functional and morphological tumor imaging without reliance on multi-injections.

  5. Stabilized radio frequency quadrupole

    DOEpatents

    Lancaster, H.D.; Fugitt, J.A.; Howard, D.R.

    1984-12-25

    Disclosed is a long-vane stabilized radio frequency resonator for accelerating charged particles and including means defining a radio frequency resonator cavity, a plurality of long vanes mounted in the defining means for dividing the cavity into sections, and means interconnecting opposing ones of the plurality of vanes for stabilizing the resonator. 5 figs.

  6. Stabilized radio frequency quadrupole

    DOEpatents

    Lancaster, Henry D.; Fugitt, Jock A.; Howard, Donald R.

    1984-01-01

    A long-vane stabilized radio frequency resonator for accelerating charged particles and including means defining a radio frequency resonator cavity, a plurality of long vanes mounted in the defining means for dividing the cavity into sections, and means interconnecting opposing ones of the plurality of vanes for stabilizing the resonator.

  7. 23Na magic-angle spinning nuclear magnetic resonance of central and satellite transitions in the characterization of the anhydrous, dihydrate, and mixed phases of sodium molybdate and tungstate.

    PubMed

    Skibsted, J; Jakobsen, H J

    1994-02-01

    23Na Magic-angle spinning nuclear magnetic resonance (MAS NMR) spectra of pure phases for Na2MoO4, Na2MoO4 x 2H2O, Na2WO4, and Na2WO4 x 2H2O have led to the determination of accurate values for the quadrupole coupling parameters and isotropic chemical shifts for all Na sites. The analysis of the spectra involves a combination of simulations of the line shapes for the central transitions and the manifold of spinning sidebands for the satellite transitions. The spectral parameters for the pure phases represent a prerequisite for a correct assignment and quantitative evaluation of 23Na MAS spectra at different magnetic field strengths observed for mixtures of the anhydrous and dihydrate phases. Such phase mixtures are observed, for example, for some commercial samples of Na2MoO4 or may be generated by (i) exposure of the anhydrous phases to a humid atmosphere or (ii) gently heating the dihydrates. The quadrupole coupling parameters for the two Na sites in the dihydrates are tentatively assigned to the two crystallographically distinct Na atoms in the asymmetric unit by calculations of an approximate dependency of the electric field gradient tensor on the local geometry for the Na sites.

  8. Electrically detected nuclear magnetic resonance in GaAs/AlGaAs-based quantum point contacts

    NASA Astrophysics Data System (ADS)

    Keane, Zachary; Godfrey, Matthew; Burke, Adam; Chen, Jason; Fricke, Sebastian; Klochan, Oleh; Micolich, Adam; Beere, Harvey; Ritchie, Dave; Trunov, Kirill; Reuter, Dirk; Wieck, Andreas; Hamilton, Alex

    2011-03-01

    Nuclear magnetic resonance (NMR) is a well-known technique with widespread applications in physics, chemistry and medicine. Conventional NMR studies use inductive coils to detect the magnetic field produced by precessing nuclear spins; this approach requires on the order of 1012 spins for detection. Recently, resistive detection of NMR through the hyperfine interaction has been demonstrated with electrons in mesoscopic 2- and 1-dimensional devices based on high-quality GaAs/AlGaAs heterostructures. These studies are typically sensitive to 108 spins, enabling NMR on much smaller sample volumes. Holes are predicted to have much weaker nuclear spin coupling than electrons, which could be relevant to the emerging fields of spintronics and quantum information processing. We present a preliminary comparison between the magnitude of the NMR signal in electron and hole quantum point contacts.

  9. High Repetition Rate, LINAC-Based Nuclear Resonance Fluorescence FY 2008 Final Report

    SciTech Connect

    Scott M Watson; Mathew T Kinlaw; James L Jones; Alan W. Hunt; Glen A. Warren

    2008-12-01

    This summarizes the first year of a multi-laboratory/university, multi-year effort focusing on high repetition rate, pulsed LINAC-based nuclear resonance fluorescence (NRF) measurements. Specifically, this FY2008 effort centered on experimentally assessing NRF measurements using pulsed linear electron accelerators, operated at various repetition rates, and identifying specific detection requirements to optimize such measurements. Traditionally, interest in NRF as a detection technology, which continues to receive funding from DHS and DOE/NA-22, has been driven by continuous-wave (CW), Van de Graff-based bremsstrahlung sources. However, in addition to the relatively sparse present-day use of Van de Graff sources, only limited NRF data from special nuclear materials has been presented; there is even less data available regarding shielding effects and photon source optimization for NRF measurements on selected nuclear materials.

  10. Quadrupole Collectivity in Neutron Deficient Sn Isotopes

    NASA Astrophysics Data System (ADS)

    Gade, Alexandra

    2014-03-01

    One of the overarching goals of nuclear physics is the development of a comprehensive model of the atomic nucleus with predictive power across the nuclear chart. Of particular importance for the development of nuclear models is experimental data that consistently track the effect of isospin and changed binding, for example. The chain of Sn isotopes has been a formidable testing ground for nuclear models as some spectroscopic data is available from N = Z = 50 100Sn in the proximity of the proton dripline to 134Sn, beyond the very neutron-rich doubly magic nucleus 132Sn. In even-even nuclei, the electromagnetic quadrupole excitation strength is a measure of quadrupole collectivity, sensitive to the presence of shell gaps, nuclear deformation, and nucleon-nucleon correlations, for example. In the Sn isotopes, this transition strength has been reported from 104Sn to 130Sn, spanning a chain of 14 even-even Sn isotopes. The trend is asymmetric with respect to midshell and not even the largest-scale shell-model calculations have been able to describe the evolution of transition strength across the isotopic chain without varying effective charges. Implications will be discussed. This work was supported by the National Science Foundation under Grant No. PHY-1102511.

  11. Space charge induced nonlinear effects in quadrupole ion traps.

    PubMed

    Guo, Dan; Wang, Yuzhuo; Xiong, Xingchuang; Zhang, Hua; Zhang, Xiaohua; Yuan, Tao; Fang, Xiang; Xu, Wei

    2014-03-01

    A theoretical method was proposed in this work to study space charge effects in quadrupole ion traps, including ion trapping, ion motion frequency shift, and nonlinear effects on ion trajectories. The spatial distributions of ion clouds within quadrupole ion traps were first modeled for both 3D and linear ion traps. It is found that the electric field generated by space charge can be expressed as a summation of even-order fields, such as quadrupole field, octopole field, etc. Ion trajectories were then solved using the harmonic balance method. Similar to high-order field effects, space charge will result in an "ocean wave" shape nonlinear resonance curve for an ion under a dipolar excitation. However, the nonlinear resonance curve will be totally shifted to lower frequencies and bend towards ion secular frequency as ion motion amplitude increases, which is just the opposite effect of any even-order field. Based on theoretical derivations, methods to reduce space charge effects were proposed.

  12. Advanced Paramagnetic Resonance Spectroscopies of Iron-Sulfur Proteins: Electron Nuclear Double Resonance (ENDOR) and Electron Spin Echo Envelope Modulation (ESEEM)

    PubMed Central

    Cutsail, George E.; Telser, Joshua; Hoffman, Brian M.

    2015-01-01

    The advanced electron paramagnetic resonance (EPR) techniques, electron nuclear double resonance (ENDOR) and electron spin echo envelope modulation (ESEEM) spectroscopies, provide unique insights into the structure, coordination chemistry, and biochemical mechanism of Nature’s widely distributed iron-sulfur cluster (FeS) proteins. This review describes the ENDOR and ESEEM techniques and then provides a series of case studies on their application to a wide variety of FeS proteins including ferredoxins, nitrogenase, and radical SAM enzymes. PMID:25686535

  13. Solid state nuclear magnetic resonance with magic-angle spinning and dynamic nuclear polarization below 25 K

    PubMed Central

    Thurber, Kent R.; Potapov, Alexey; Yau, Wai-Ming; Tycko, Robert

    2012-01-01

    We describe an apparatus for solid state nuclear magnetic resonance (NMR) with dynamic nuclear polarization (DNP) and magic-angle spinning (MAS) at 20–25 K and 9.4 Tesla. The MAS NMR probe uses helium to cool the sample space and nitrogen gas for MAS drive and bearings, as described earlier (Thurber et al., J. Magn. Reson. 2008) [1], but also includes a corrugated waveguide for transmission of microwaves from below the probe to the sample. With a 30 mW circularly polarized microwave source at 264 GHz, MAS at 6.8 kHz, and 21 K sample temperature, greater than 25-fold enhancements of cross-polarized 13C NMR signals are observed in spectra of frozen glycerol/water solutions containing the triradical dopant DOTOPA-TEMPO when microwaves are applied. As demonstrations, we present DNP-enhanced one-dimensional and two-dimensional 13C MAS NMR spectra of frozen solutions of uniformly 13C-labeled L-alanine and melittin, a 26-residue helical peptide that we have synthesized with four uniformly 13C-labeled amino acids. PMID:23238592

  14. [Recent progress in nuclear magnetic resonance spectrum for drug research and development].

    PubMed

    Zhong, Jun; Jiang, Xue-mei

    2015-01-01

    In the process of modern drug research, the new methods and technologies which can detect drug molecules' chemical composition, structure and interaction with biomolecules are always the key scientific problems people care about. Spectra (including IR, UV and NMR) are the most common analytical methods, of which NMR can obtain detailed parameter about the nucleus of organic molecules through researching the laws of nuclear transition in the impact of surrounding chemical environment. The parameter contains rich information about the chemical composition, structure and interaction with other molecules of organic molecules. In many complex environments, such as liquid, solid or gas state, even biological in situ environment, NMR can provide molecules' chemical composition, atomic-resolution three-dimensional structure, information of interaction with each other and dynamic process, especially the information about drug interacting with biomacromolecules. In recent years, the applications of nuclear magnetic resonance spectrum in drug research and development are more and more widespread. This paper reviewed its recent progress in structure and dynamic of targeted biological macromolecules, drug design and screening and drug metabolism in drug research and development. In the first part, we gave a brief introduction of nuclear magnetic resonance technology and its applications in drug research. In the second part, we explained the basic principles briefly and summarized progress in methods and techniques for drug research. In the third part, we discussed applications of nuclear magnetic resonance ir structure and dynamic of targeted biological macromolecules, drug design and screening and drug metabolism in detail. The conclusions were stated in the last part.

  15. [Recent progress in nuclear magnetic resonance spectrum for drug research and development].

    PubMed

    Zhong, Jun; Jiang, Xue-mei

    2015-01-01

    In the process of modern drug research, the new methods and technologies which can detect drug molecules' chemical composition, structure and interaction with biomolecules are always the key scientific problems people care about. Spectra (including IR, UV and NMR) are the most common analytical methods, of which NMR can obtain detailed parameter about the nucleus of organic molecules through researching the laws of nuclear transition in the impact of surrounding chemical environment. The parameter contains rich information about the chemical composition, structure and interaction with other molecules of organic molecules. In many complex environments, such as liquid, solid or gas state, even biological in situ environment, NMR can provide molecules' chemical composition, atomic-resolution three-dimensional structure, information of interaction with each other and dynamic process, especially the information about drug interacting with biomacromolecules. In recent years, the applications of nuclear magnetic resonance spectrum in drug research and development are more and more widespread. This paper reviewed its recent progress in structure and dynamic of targeted biological macromolecules, drug design and screening and drug metabolism in drug research and development. In the first part, we gave a brief introduction of nuclear magnetic resonance technology and its applications in drug research. In the second part, we explained the basic principles briefly and summarized progress in methods and techniques for drug research. In the third part, we discussed applications of nuclear magnetic resonance ir structure and dynamic of targeted biological macromolecules, drug design and screening and drug metabolism in detail. The conclusions were stated in the last part. PMID:25993865

  16. Nuclear resonance scattering of synchrotron radiation as a unique electronic, structural and thermodynamic probe

    SciTech Connect

    Alp, E. Ercan; Sturhahn, Wolfgang; Toellner, Thomas S.; Zhao, Jiyong; Leu, Bogdan M.

    2012-05-09

    Discovery of Moessbauer effect in a nuclear transition was a remarkable development. It revealed how long-lived nuclear states with relatively low energies in the kiloelectron volt (keV) region can be excited without recoil. This new effect had a unique feature involving a coupling between nuclear physics and solid-state physics, both in terms of physics and sociology. Physics coupling originates from the fact that recoilless emission and absorption or resonance is only possible if the requirement that nuclei have to be bound in a lattice with quantized vibrational states is fulfilled, and that the finite electron density on the nucleus couples to nuclear degrees of freedom leading to hyperfine interactions. thus, Moessbauer spectroscopy allows peering into solid-state effects using unique nuclear transitions. Sociological aspects of this coupling had been equally startling and fruitful. The interaction between diverse scientific communities, who learned to use Moessbauer spectroscopy proved to be very valuable. For example, biologists, geologists, chemists, physics, materials scientists, and archeologists, all sharing a common spectroscopic technique, also learned to appreciate the beauty and intricacies of each other's fields. As a laboratory-based technique, Moessbauer spectroscopy matured by the end of the 1970s. Further exciting developments took place when accelerator-based techniques were employed, like synchrotron radiation or 'in-beam'Moessbauer experiments with implanted radioactive ions. More recently, two Moessbauer spectrometers on the surface of the Mars kept the technique vibrant and viable up until present time. In this chapter, the authors look into some of the unique aspects of nuclear resonance excited with synchrotron radiation as a probe of condensed matter, including magnetism, valence, vibrations, and lattice dynamics, and review the development of nuclear resonance inelastic x-ray scattering (NRIXS) and synchrotron Moessbauer spectroscopy

  17. [Value of the nuclear magnetic cholangio resonance in the study of the patient with jaundice].

    PubMed

    Gramática, L; Struni, M; Carranza, D; Verasay, G; Taborda, B; Caballero, F; Gramática, L

    1999-01-01

    This report analyse the results about forty three (43) patients, thirty six (36) of which showed an extrahepatic obstructive biliary Syndrome was made evident by ultrasonography, five (5) with a cholecistolithiasis and doubtful history of jaundice were evaluated to carry out a video-surgery procedure and two (2) patients whom hepatic-yeyunostomy had been practiced, a control of anastomosis in postoperative period was required. Nuclear Magnetic Resonance and Operative Cholangiography findings were correlated and afterward with the anatomopathological studies when they arrived. In all cases the Nuclear Magnetic Cholangio Resonance (NMCR) let us prove the diagnosis of extrahepatic biliary obstruction determining with precision furthermore the topographical site of the lesion. Respecting the aetiology of obstruction, NMCR was accurate in 34 out of 36 cases (94.4%). In conclusion Cholangio-Resonance is an excellent diagnostic method to evaluate biliary ductal system including anatomic changes. However, there are some limitations yet in order to determine the aetiology of lesions about extrahepatic biliary via extremes. We emphasize its features such as non-invasive, little operating dependent, and without morbimortality that become it as a method of choice to study the biliary via from a diagnostic viewpoint.

  18. Effect of 1. 5 tesla nuclear magnetic resonance imaging scanner on implanted permanent pacemakers

    SciTech Connect

    Hayes, D.L.; Holmes, D.R. Jr.; Gray, J.E.

    1987-10-01

    Patients with a permanent pacemaker are currently restricted from diagnostic nuclear magnetic resonance (NMR) imaging because of potential adverse effects on the pacemaker by the magnet. Previous work has shown that NMR imaging will result in asynchronous pacing of the pulse generator within a given distance of the magnet. The radiofrequency signal generated by the system may also result in rapid cardiac pacing, which may have deleterious effects. This study utilized a 1.5 tesla unit in an in vivo laboratory animal to evaluate the unit's effects on eight different pulse generators from two manufacturers. All pacemakers functioned in an asynchronous mode when placed within a certain distance of the magnet. In addition, transient reed switch inhibition was observed. Seven of the eight pulse generators paced rapidly when exposed to the radiofrequency signal and there was a dramatic decrease in arterial blood pressure. Whether effective rapid cardiac pacing would occur could not be predicted before exposure to the magnetic resonance unit. Nuclear magnetic resonance imaging with high magnetic fields in patients with a pacemaker should continue to be avoided until the mechanism of the rapid cardiac pacing can be further delineated and either predicted or prevented.

  19. Electron spin resonance and electron nuclear double resonance of photogenerated polarons in polyfluorene and its fullerene composite

    NASA Astrophysics Data System (ADS)

    Marumoto, K.; Kato, M.; Kondo, H.; Kuroda, S.; Greenham, N. C.; Friend, R. H.; Shimoi, Y.; Abe, S.

    2009-06-01

    Electron spin resonance (ESR) and electron-nuclear double resonance (ENDOR) of photogenerated polarons in poly(9,9-dioctylfluorene) (PFO) and its composite with fullerene (C60) using variable photoexcitation energy up to 4.1 eV are reported. For PFO, a light-induced ESR (LESR) signal (g=2.003) is observed below 60 K, and its transient response and excitation spectrum indicate that the observed spins are photogenerated polarons on PFO. For the PFO-C60 composite, two LESR signals of photogenerated positive polarons on PFO (g1=2.003) and radical anions on C60 (g2=1.999) , respectively, are observed below 120 K, which are caused by photoinduced electron transfer from PFO to C60 . A remarkable enhancement of the LESR signals in the excitation spectrum at ˜2.8eV is observed compared with the case of pure PFO. The bimolecular-recombination kinetics of photogenerated charge carriers in the composite are confirmed by the dependence of the LESR on excitation-light intensity and by the decay dynamics. Light-induced ENDOR (LENDOR) signals are clearly observed for excitation around 2.8 eV owing to the highly efficient photoinduced electron transfer in the composite. Broad LENDOR shifts directly reflect the spin-density distribution of the polarons in PFO. We have determined its maximum shift using LENDOR-induced ESR, and have evaluated the maximum spin density on the carbon site coupled to the proton as 0.032. This value is consistent with the theoretical result obtained by Pariser-Parr-Pople (PPP) model, where the spatial extent of the polarons is calculated as ˜3 monomer units of PFO. The calculated LESR spectra of PFO based on the PPP model are consistent with the experimental spectra, which confirm the above spatial extension of the polaron in PFO.

  20. Logical operations with single x-ray photons via dynamically-controlled nuclear resonances.

    PubMed

    Gunst, Jonas; Keitel, Christoph H; Pálffy, Adriana

    2016-04-27

    Photonic qubits lie at the heart of quantum information technology, often encoding information in their polarization state. So far, only low-frequency optical and infrared photons have been employed as flying qubits, as the resources that are at present easiest to control. With their essentially different way of interacting with matter, x-ray qubits would bear however relevant advantages: they are extremely robust, penetrate deep through materials, and can be focused down to few-nm waveguides, allowing unprecedented miniaturization. Also, x-rays are resonant to nuclear transitions, which are very well isolated from the environment and present long coherence times. Here, we show theoretically that x-ray polarization qubits can be dynamically controlled by nuclear Mössbauer resonances. The control knob is played by nuclear hyperfine magnetic fields, that allow via fast rotations precise processing of single x-ray quanta polarization. With such rotations, single-qubit and binary logical operations such as a destructive C-NOT gate can be implemented.

  1. Logical operations with single x-ray photons via dynamically-controlled nuclear resonances

    NASA Astrophysics Data System (ADS)

    Gunst, Jonas; Keitel, Christoph H.; Pálffy, Adriana

    2016-04-01

    Photonic qubits lie at the heart of quantum information technology, often encoding information in their polarization state. So far, only low-frequency optical and infrared photons have been employed as flying qubits, as the resources that are at present easiest to control. With their essentially different way of interacting with matter, x-ray qubits would bear however relevant advantages: they are extremely robust, penetrate deep through materials, and can be focused down to few-nm waveguides, allowing unprecedented miniaturization. Also, x-rays are resonant to nuclear transitions, which are very well isolated from the environment and present long coherence times. Here, we show theoretically that x-ray polarization qubits can be dynamically controlled by nuclear Mössbauer resonances. The control knob is played by nuclear hyperfine magnetic fields, that allow via fast rotations precise processing of single x-ray quanta polarization. With such rotations, single-qubit and binary logical operations such as a destructive C-NOT gate can be implemented.

  2. Logical operations with single x-ray photons via dynamically-controlled nuclear resonances.

    PubMed

    Gunst, Jonas; Keitel, Christoph H; Pálffy, Adriana

    2016-01-01

    Photonic qubits lie at the heart of quantum information technology, often encoding information in their polarization state. So far, only low-frequency optical and infrared photons have been employed as flying qubits, as the resources that are at present easiest to control. With their essentially different way of interacting with matter, x-ray qubits would bear however relevant advantages: they are extremely robust, penetrate deep through materials, and can be focused down to few-nm waveguides, allowing unprecedented miniaturization. Also, x-rays are resonant to nuclear transitions, which are very well isolated from the environment and present long coherence times. Here, we show theoretically that x-ray polarization qubits can be dynamically controlled by nuclear Mössbauer resonances. The control knob is played by nuclear hyperfine magnetic fields, that allow via fast rotations precise processing of single x-ray quanta polarization. With such rotations, single-qubit and binary logical operations such as a destructive C-NOT gate can be implemented. PMID:27118340

  3. Logical operations with single x-ray photons via dynamically-controlled nuclear resonances

    PubMed Central

    Gunst, Jonas; Keitel, Christoph H.; Pálffy, Adriana

    2016-01-01

    Photonic qubits lie at the heart of quantum information technology, often encoding information in their polarization state. So far, only low-frequency optical and infrared photons have been employed as flying qubits, as the resources that are at present easiest to control. With their essentially different way of interacting with matter, x-ray qubits would bear however relevant advantages: they are extremely robust, penetrate deep through materials, and can be focused down to few-nm waveguides, allowing unprecedented miniaturization. Also, x-rays are resonant to nuclear transitions, which are very well isolated from the environment and present long coherence times. Here, we show theoretically that x-ray polarization qubits can be dynamically controlled by nuclear Mössbauer resonances. The control knob is played by nuclear hyperfine magnetic fields, that allow via fast rotations precise processing of single x-ray quanta polarization. With such rotations, single-qubit and binary logical operations such as a destructive C-NOT gate can be implemented. PMID:27118340

  4. Nuclear Magnetic Resonance in the Highly Anisotropic Rare EARTH-COBALT(5) Compounds.

    NASA Astrophysics Data System (ADS)

    Kunkel, Henry Peter

    The NMR spectra of magnetic materials containing domain walls and having a large anisotropy in the hyperfine field show two NMR peaks arising from a single site; one peak arising from nuclei located at the domain-wall-centre and the other peak arising from nuclei located at the domain -wall-edge. The identification of the origin of the observed peaks therefore gives a simple measurement of the total anisotropy in the hyperfine field. Techniques have been developed to identify the nature of the various peaks observed in the Co('59) NMR resonances in the RCo(,5) compounds. The modulation of the spin echo decay envelope by an external a.c. field has been observed. An enhancement of the external longitudinal modulating field resulting from the anisotropy in the hyperfine field has been identified. This is analogous to the enhancement of a transverse r.f. field by the isotropic hyperfine field which is characteristic of NMR in ferromagnetic materials. The observation of quadrupole splitting effects has been correlated to the rate of change of the hyperfine field in the domain wall as measured by the modulation experiment. The orbital contribution to the anisotropy in the hyperfine field consists of two contributions; one arising from the anisotropy in the crystal field and the other from an anisotropy in the spin-orbit interaction. A phenomenological model is presented which can consistently account for the data available on the anisotropy in the hyperfine field, the anisotropy in the magnetization and the magnetocrystalline anisotropy. The correlation between the anisotropy in the hyperfine field and the magnetocrystalline anisotropy represents an interesting new procedure for the study of the magnetocrystalline anisotropy and would therefore be of particular use in the fabrication of improved permanent magnetic materials.

  5. Nuclear resonant inelastic X-ray scattering at high pressure and low temperature

    DOE PAGES

    Bi, Wenli; Zhao, Jiyong; Lin, Jung -Fu; Jia, Quanjie; Hu, Michael Y.; Jin, Changqing; Ferry, Richard; Yang, Wenge; Struzhkin, Viktor; Alp, E. Ercan

    2015-01-01

    In this study, a new synchrotron radiation experimental capability of coupling nuclear resonant inelastic X-ray scattering with the cryogenically cooled high-pressure diamond anvil cell technique is presented. The new technique permits measurements of phonon density of states at low temperature and high pressure simultaneously, and can be applied to studies of phonon contribution to pressure- and temperature-induced magnetic, superconducting and metal–insulator transitions in resonant isotope-bearing materials. In this report, a pnictide sample, EuFe2As2, is used as an example to demonstrate this new capability at beamline 3-ID of the Advanced Photon Source, Argonne National Laboratory. A detailed description of the technicalmore » development is given. The Fe-specific phonon density of states and magnetism from the Fe sublattice in Eu57Fe2As2 at high pressure and low temperature were derived by using this new capability.« less

  6. Nuclear magnetic resonance apparatus having semitoroidal rf coil for use in topical NMR and NMR imaging

    DOEpatents

    Fukushima, Eiichi; Roeder, Stephen B. W.; Assink, Roger A.; Gibson, Atholl A. V.

    1986-01-01

    An improved nuclear magnetic resonance (NMR) apparatus for use in topical magnetic resonance (TMR) spectroscopy and other remote sensing NMR applications includes a semitoroidal radio-frequency (rf) coil. The semitoroidal rf coil produces an effective alternating magnetic field at a distance from the poles of the coil, so as to enable NMR measurements to be taken from selected regions inside an object, particularly including human and other living subjects. The semitoroidal rf coil is relatively insensitive to magnetic interference from metallic objects located behind the coil, thereby rendering the coil particularly suited for use in both conventional and superconducting NMR magnets. The semitoroidal NMR coil can be constructed so that it emits little or no excess rf electric field associated with the rf magnetic field, thus avoiding adverse effects due to dielectric heating of the sample or to any other interaction of the electric field with the sample.

  7. Line broadening interference for high-resolution nuclear magnetic resonance spectra under inhomogeneous magnetic fields

    SciTech Connect

    Wei, Zhiliang; Yang, Jian; Lin, Yanqin E-mail: chenz@xmu.edu.cn; Chen, Zhong E-mail: chenz@xmu.edu.cn; Chen, Youhe

    2015-04-07

    Nuclear magnetic resonance spectroscopy serves as an important tool for analyzing chemicals and biological metabolites. However, its performance is subject to the magnetic-field homogeneity. Under inhomogeneous fields, peaks are broadened to overlap each other, introducing difficulties for assignments. Here, we propose a method termed as line broadening interference (LBI) to provide high-resolution information under inhomogeneous magnetic fields by employing certain gradients in the indirect dimension to interfere the magnetic-field inhomogeneity. The conventional spectral-line broadening is thus interfered to be non-diagonal, avoiding the overlapping among adjacent resonances. Furthermore, an inhomogeneity correction algorithm is developed based on pattern recognition to recover the high-resolution information from LBI spectra. Theoretical deductions are performed to offer systematic and detailed analyses on the proposed method. Moreover, experiments are conducted to prove the feasibility of the proposed method for yielding high-resolution spectra in inhomogeneous magnetic fields.

  8. Line broadening interference for high-resolution nuclear magnetic resonance spectra under inhomogeneous magnetic fields.

    PubMed

    Wei, Zhiliang; Yang, Jian; Chen, Youhe; Lin, Yanqin; Chen, Zhong

    2015-04-01

    Nuclear magnetic resonance spectroscopy serves as an important tool for analyzing chemicals and biological metabolites. However, its performance is subject to the magnetic-field homogeneity. Under inhomogeneous fields, peaks are broadened to overlap each other, introducing difficulties for assignments. Here, we propose a method termed as line broadening interference (LBI) to provide high-resolution information under inhomogeneous magnetic fields by employing certain gradients in the indirect dimension to interfere the magnetic-field inhomogeneity. The conventional spectral-line broadening is thus interfered to be non-diagonal, avoiding the overlapping among adjacent resonances. Furthermore, an inhomogeneity correction algorithm is developed based on pattern recognition to recover the high-resolution information from LBI spectra. Theoretical deductions are performed to offer systematic and detailed analyses on the proposed method. Moreover, experiments are conducted to prove the feasibility of the proposed method for yielding high-resolution spectra in inhomogeneous magnetic fields.

  9. Analysis of ringing effects due to magnetic core materials in pulsed nuclear magnetic resonance circuits

    SciTech Connect

    Prabhu Gaunkar, N. Bouda, N. R. Y.; Nlebedim, I. C.; Hadimani, R. L.; Mina, M.; Jiles, D. C.; Bulu, I.; Ganesan, K.; Song, Y. Q.

    2015-05-07

    This work presents investigations and detailed analysis of ringing in a non-resonant pulsed nuclear magnetic resonance (NMR) circuit. Ringing is a commonly observed phenomenon in high power switching circuits. The oscillations described as ringing impede measurements in pulsed NMR systems. It is therefore desirable that those oscillations decay fast. It is often assumed that one of the causes behind ringing is the role of the magnetic core used in the antenna (acting as an inductive load). We will demonstrate that an LRC subcircuit is also set-up due to the inductive load and needs to be considered due to its parasitic effects. It is observed that the parasitics associated with the inductive load become important at certain frequencies. The output response can be related to the response of an under-damped circuit and to the magnetic core material. This research work demonstrates and discusses ways of controlling ringing by considering interrelationships between different contributing factors.

  10. Nuclear Resonance Vibrational Spectra of Five-Coordinate Imidazole-ligated Iron(II) Porphyrinates

    PubMed Central

    Hu, Chuanjiang; Barabanschikov, Alexander; Ellison, Mary K.; Zhao, Jiyong; Alp, E. Ercan; Sturhahn, Wolfgang; Zgierski, Marek Z.; Sage, J. Timothy; Scheidt, W. Robert

    2012-01-01

    Nuclear resonance vibrational spectra have been obtained for six five-coordinate imidazole-ligated iron(II) porphyrinates, [Fe(Por)(L)] (Por = tetraphenylporphyrinate, octaethylporphyrinate, tetratolylporphyrinate or protoporphyrinate IX and L = 2-methylimidazole or 1,2-dimethylimidazole). Measurements have been made on both powder and oriented crystal samples. The spectra are dominated by strong signals around 200–300 cm−1. Although the in-plane and out-of-plane vibrations are seriously overlapped, oriented crystal spectra allow their deconvolution. Thus, oriented crystal experimental data, along with DFT calculations, enable the assignment of key vibrations in the spectra. Molecular dynamics are also discussed. The nature of the Fe–NIm vibrations has been elaborated further than was possible from resonance Raman studies. Our study suggests that the Fe motions are coupled with the porphyrin core and peripheral groups motions. Both peripheral groups and their conformations have significant influence on the vibrational spectra (position and shape). PMID:22243131

  11. Fluorine-19 nuclear magnetic resonance and biochemical characterization of fluorotyrosine-labeled-thymidylate-synthetase

    NASA Astrophysics Data System (ADS)

    Rosson, Dan; Lewis, Charles A.; Ellis, Paul D.; Dunlap, R. Bruce

    1994-03-01

    Fluorotyrosine has been incorporated into thymidylate synthetase from Lactobacillus casei by growth of the bacterium in media containing 3-fluorotyrosine. The enzyme exhibited a specific activity 70% of that of the normal enzyme and formed a covalent binary complex with pyrimidine nucleotides, as well as a covalent ternary complex with 5-fluorodeoxyuridylate and 5,10-methylenetetrahydrofolate. 19F nuclear magnetic resonance spectroscopy has been used to follow the formation of these complexes. 5-Fluorodeoxyuridylate, dUMP, dTMP and dCMP produced identical conformational changes in the enzyme as monitored by the fluorotyrosyl resonances. Ternary complex formation of the fluorotyrosine-containing enzyme with 5-fluorodeoxyuridylate and 5,10-methylenetetrahydrofolate resulted in further spectral changes.

  12. 77Se nuclear magnetic resonance of topological insulator Bi2Se3

    NASA Astrophysics Data System (ADS)

    Georgieva, Nataliya M.; Rybicki, Damian; Guehne, Robin; Williams, Grant V. M.; Chong, Shen V.; Kadowaki, Kazuo; Garate, Ion; Haase, Jürgen

    2016-05-01

    Topological insulators constitute a new class of materials with an energy gap in the bulk and peculiar metallic states on the surface. We report on new features resulting from the bulk electronic structure, based on a comprehensive nuclear magnetic resonance (NMR) study of 77Se on Bi2Se3 and Cu0.15Bi2Se3 single crystals. First, we find two resonance lines and show that they originate from the two inequivalent Se lattice sites. Second, we observe unusual field-independent linewidths and attribute them to an unexpectedly strong internuclear coupling mediated by bulk electrons. In order to support this interpretation, we present a model calculation of the indirect internuclear coupling and show that the Bloembergen-Rowland coupling is much stronger than the Ruderman-Kittel-Kasuya-Yosida coupling. Our results call for a revision of earlier NMR studies and add information concerning the bulk electronic properties.

  13. Demonstration of a transmission nuclear resonance fluorescence measurement for a realistic radioactive waste canister scenario

    NASA Astrophysics Data System (ADS)

    Angell, C. T.; Hajima, R.; Hayakawa, T.; Shizuma, T.; Karwowski, H. J.; Silano, J.

    2015-03-01

    Transmission nuclear resonance fluorescence (NRF) is a promising method for precision non-destructive assay (NDA) of fissile isotopes-including 239Pu-in spent fuel while inside a storage canister. The assay, however, could be confounded by the presence of overlapping resonances from competing isotopes in the canister. A measurement is needed to demonstrate that transmission NRF is unaffected by the shielding material. To this end, we carried out a transmission NRF measurement using a mono-energetic γ-ray beam on a proxy target (Al) and absorbing material simulating a realistic spent fuel storage canister. Similar amounts of material as would be found in a possible spent fuel storage canister were placed upstream: concrete, stainless steel (SS 304), lead (as a proxy for U), and water. An Al absorption target was also used as a reference. These measurements demonstrated that the canister material should not significantly influence the non-destructive assay.

  14. Method for determining fast-alpha-particle confinement in tokamak plasmas using resonant nuclear reactors

    SciTech Connect

    Cecil, F.E.; Zweben, S.J.; Medley, S.S.

    1986-03-01

    The resonant nuclear reactions D(..cap alpha..,..gamma..)/sup 6/Li, /sup 6/Li(..cap alpha..,..gamma..)/sup 10/B, and /sup 7/Li(..cap alpha..,..gamma..)/sup 11/B are examined as diagnostics of fast-alpha-particle confinement in tokamak plasmas. Gamma rays from these resonant reactions with energies from 2.1 MeV to 9.2 MeV may be used to infer the alpha-particle population between energies of 0.4 MeV and 2.6 MeV. The ratio of these alpha-burnup reactions to the reactions T(D,..gamma..)/sup 5/He and /sup 3/He(D,..gamma..)/sup 5/Li provides a technique for the measurement of alpha confinement.

  15. Nuclear resonant forward scattering of synchrotron radiation from 121 Sb at 37.13 keV.

    SciTech Connect

    Wille, H. C.; Shvydko, Y. V.; Alp, E. E.; Ruter, H. D.; Leupold, O.; Sergueev, I.; Ruffer, R.; Barla, A.; Sanchez, J. P.; X-Ray Science Division; European Synchrotron Radiation Facility; Univ. of Hamburg; Hamburder Synchrotronstrahlungslabor

    2006-02-22

    We report on the observation of nuclear resonant forward scattering of synchrotron radiation from {sup 121}Sb nuclei. A temperature stabilized {alpha}Al{sub 2}O{sub 3} crystal Bragg backscattering high-resolution monochromator with a relative energy resolution of 2 x 10{sup -7} was introduced. As first spectroscopic applications the hyperfine parameters in Sb{sub 2}O{sub 3}, USb and DySb were determined. The energy of the nuclear transition in {sup 121}Sb was measured to be 37.1298(2)keV, 40 times more precisely than reported before. The results open the field of nuclear resonance spectroscopy on antimony compounds taking advantage of the outstanding features of 3rd-generation synchrotron sources. Nuclear resonance scattering on Sb compounds at these sources allows element-specific dynamical studies on thermoelectric materials as well as studies on magnetism in micro- and nanometer dimensional systems like spintronic devices.

  16. Flocculation Effects on Bound Water in Sludges as Measured by Nuclear Magnetic Resonance Spectroscopy

    PubMed Central

    Carberry, Judith Bower; Prestowitz, Robert A.

    1985-01-01

    Nuclear magnetic resonance relaxation times (T1 and T2) were measured for flocculated and unflocculated samples of activated sludge. The weight of water and solids in the sludge samples was found and related to T1 to find the relative percentage of bound water. The results suggest that the amount of bound water increases as the samples become more unflocculated. The values of T1 and T2 also indicate that unflocculated individual particles are characterized by loose packing of shorter molecules and that the addition of larger molecules may induce flocculation. PMID:16346723

  17. Two-dimensional nuclear magnetic resonance studies of molecular structure in liquids and liquid crystals

    SciTech Connect

    Rucker, S.P.

    1991-07-01

    Magnetic couplings between protons, such as through-space dipole couplings, and scalar J-couplings depend sensitively on the structure of the molecule. Two dimensional nuclear magnetic resonance experiments provide a powerful tool for measuring these couplings, correlating them to specific pairs of protons within the molecule, and calculating the structure. This work discusses the development of NMR methods for examining two such classes of problems -- determination of the secondary structure of flexible molecules in anisotropic solutions, and primary structure of large biomolecules in aqueous solutions. 201 refs., 84 figs., 19 tabs.

  18. High-resolution proton nuclear magnetic resonance characterization of seminolipid from bovine spermatozoa.

    PubMed

    Alvarez, J G; Storey, B T; Hemling, M L; Grob, R L

    1990-06-01

    The high-resolution one- and two-dimensional proton nuclear magnetic resonance (1H-NMR) characterization of seminolipid from bovine spermatozoa is presented. The 1H-NMR data was confirmed by gas-liquid chromatography-mass spectrometric analysis of the partially methylated alditol acetates of the sugar unit, mild alkaline methanolysis of the glyceryl ester, mobility on normal phase and diphasic thin-layer chromatography (HPTLC), and fast atom bombardment mass spectrometry (FAB-MS). The structure of the molecule corresponds to 1-O-hexadecyl-2-O-hexadecanoyl-3-O-beta-D-(3'-sulfo)-galactopyranosyl- sn-glycerol. PMID:2373957

  19. Nanoscale nuclear magnetic resonance with a 1.9-nm-deep nitrogen-vacancy sensor

    SciTech Connect

    Loretz, M.; Degen, C. L.; Pezzagna, S.; Meijer, J.

    2014-01-20

    We present nanoscale nuclear magnetic resonance (NMR) measurements performed with nitrogen-vacancy (NV) centers located down to about 2 nm from the diamond surface. NV centers were created by shallow ion implantation followed by a slow, nanometer-by-nanometer removal of diamond material using oxidative etching in air. The close proximity of NV centers to the surface yielded large {sup 1}H NMR signals of up to 3.4 μT-rms, corresponding to ∼330 statistically polarized or ∼10 fully polarized proton spins in a (1.8 nm){sup 3} detection volume.

  20. 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.

  1. Molecular Structure Laboratory. Fourier Transform Nuclear Magnetic Resonance (FTNMR) Spectrometer and Ancillary Instrumentation at SUNY Geneseo

    SciTech Connect

    Geiger, David K

    2015-12-31

    An Agilent 400-MR nuclear magnetic resonance (NMR) spectrometer and ancillary equipment were purchased, which are being used for molecular structure elucidation.  The instrumentation is housed in a pre-existing facility designed specifically for its use. This instrument package is being used to expand the research and educational efforts of the faculty and students at SUNY-Geneseo and is made available to neighboring educational institutions and business concerns.  Funds were also used for training of College personnel, maintenance of the instrumentation, and installation of the equipment.

  2. Micro-coil detection of nuclear magnetic resonance for nanofluidic samples

    SciTech Connect

    Shibahara, A.; Casey, A.; Lusher, C. P.; Saunders, J.; Aßmann, C.; Schurig, Th.; Drung, D.

    2014-02-15

    We have developed a novel dc SQUID system with a micro-coil input circuit to act as a local probe of quantum matter and nanosystems. The planar niobium micro-coil pickup loop is located remotely from the SQUID, coupled through a superconducting twisted pair. A high degree of coupling between the coil and the region of interest of similar dimensions (up to ∼ 100 microns) can be achieved. We report nuclear magnetic resonance (NMR) measurements to characterise the sensitivity of these coils to {sup 3}He in the gas phase at 4.2 K in a 30 mT magnetic field.

  3. Material degradation of liquid organic semiconductors analyzed by nuclear magnetic resonance spectroscopy

    SciTech Connect

    Fukushima, Tatsuya; Yamamoto, Junichi; Fukuchi, Masashi; Kaji, Hironori; Hirata, Shuzo; Jung, Heo Hyo; Adachi, Chihaya; Hirata, Osamu; Shibano, Yuki

    2015-08-15

    Liquid organic light-emitting diodes (liquid OLEDs) are unique devices consisting only of liquid organic semiconductors in the active layer, and the device performances have been investigated recently. However, the device degradation, especially, the origin has been unknown. In this study, we show that material degradation occurs in liquid OLEDs, whose active layer is composed of carbazole with an ethylene glycol chain. Nuclear magnetic resonance (NMR) experiments clearly exhibit that the dimerization reaction of carbazole moiety occurs in the liquid OLEDs during driving the devices. In contrast, cleavages of the ethylene glycol chain are not detected within experimental error. The dimerization reaction is considered to be related to the device degradation.

  4. High-resolution proton nuclear magnetic resonance characterization of seminolipid from bovine spermatozoa.

    PubMed

    Alvarez, J G; Storey, B T; Hemling, M L; Grob, R L

    1990-06-01

    The high-resolution one- and two-dimensional proton nuclear magnetic resonance (1H-NMR) characterization of seminolipid from bovine spermatozoa is presented. The 1H-NMR data was confirmed by gas-liquid chromatography-mass spectrometric analysis of the partially methylated alditol acetates of the sugar unit, mild alkaline methanolysis of the glyceryl ester, mobility on normal phase and diphasic thin-layer chromatography (HPTLC), and fast atom bombardment mass spectrometry (FAB-MS). The structure of the molecule corresponds to 1-O-hexadecyl-2-O-hexadecanoyl-3-O-beta-D-(3'-sulfo)-galactopyranosyl- sn-glycerol.

  5. Combining Nuclear Magnetic Resonance Spectroscopy and Density Functional Theory Calculations to Characterize Carvedilol Polymorphs.

    PubMed

    Rezende, Carlos A; San Gil, Rosane A S; Borré, Leandro B; Pires, José Ricardo; Vaiss, Viviane S; Resende, Jackson A L C; Leitão, Alexandre A; De Alencastro, Ricardo B; Leal, Katia Z

    2016-09-01

    The experiments of carvedilol form II, form III, and hydrate by (13)C and (15)N cross-polarization magic-angle spinning (CP MAS) are reported. The GIPAW (gauge-including projector-augmented wave) method from DFT (density functional theory) calculations was used to simulate (13)C and (15)N chemical shifts. A very good agreement was found for the comparison between the global results of experimental and calculated nuclear magnetic resonance (NMR) chemical shifts for carvedilol polymorphs. This work aims a comprehensive understanding of carvedilol crystalline forms employing solution and solid-state NMR as well as DFT calculations.

  6. In vivo phosphorus-31 nuclear magnetic resonance reveals lowered ATP during heat shock of Tetrahymena

    SciTech Connect

    Findly, R.C.; Gillies, R.J.; Shulman, R.G.

    1983-03-11

    Cells synthesize a characteristic set of proteins--heat shock proteins--in response to a rapid temperature jump or certain other stress treatments. The technique of phosphorus-31 nuclear magnetic resonance spectroscopy was used to examine in vivo the effects of temperature jump on two species of Tetrahymena that initiate the heat shock response at different temperatures. An immediate 50 percent decrease in cellular adenosine triphosphate was observed when either species was jumped to a temperature that strongly induces synthesis of heat shock proteins. This new adenosine triphosphate concentration was maintained at the heat shock temperature.

  7. Application of a portable nuclear magnetic resonance surface probe to porous media.

    PubMed

    Marko, Andriy; Wolter, Bernd; Arnold, Walter

    2007-03-01

    A portable nuclear magnetic resonance (NMR) surface probe was used to determine the time-dependent self-diffusion coefficient D(t) of water molecules in two fluid-filled porous media. The measuring equipment and the inhomogeneous magnetic fields in the sensitive volume of the probe are described. It is discussed how to evaluate D(t) using a surface probe from the primary and stimulated echoes generated in three-pulse experiments. Furthermore, the evaluation of D(t) allows one to determine the geometrical structure of porous materials.

  8. {sup 1}H nuclear magnetic resonance study of hydrated water dynamics in perfluorosulfonic acid ionomer Nafion

    SciTech Connect

    Han, Jun Hee; Lee, Kyu Won; Jeon, G. W.; Lee, Cheol Eui; Park, W. K.; Choi, E. H.

    2015-01-12

    We have studied the dynamics of hydrated water molecules in the proton exchange membrane of Nafion by means of high-resolution {sup 1}H nuclear magnetic resonance (NMR) measurements. “Bound” and “free” states of hydrated water clusters as well as the exchange protons were identified from the NMR chemical shift measurements, and their activation energies were obtained from the temperature-dependent laboratory- and rotating-frame spin-lattice relaxation measurements. Besides, a peculiar motional transition in the ultralow frequency region was observed at 373 K for the “free” hydrated water from the rotating-frame NMR spin-lattice relaxation time measurements.

  9. Determination of alkylbenzenesulfonate surfactants in groundwater using macroreticular resins and carbon-13 nuclear magnetic resonance spectrometry

    USGS Publications Warehouse

    Thurman, E.M.; Willoughby, T.; Barber, L.B.; Thorn, K.A.

    1987-01-01

    Alkylbenzenesulfonate surfactants were determined in groundwater at concentrations as low as 0.3 mg/L. The method uses XAD-8 resin for concentration, followed by elution with methanol, separation of anionic and nonionic surfactants by anion exchange, quantitation by titration, and identification by 13C nuclear magnetic resonance spectrometry. Laboratory standards and field samples containing straight-chain and branched-chain alkylbenzenesulfonates, sodium dodecyl sulfate, and alkylbenzene ethoxylates were studied. The XAD-8 extraction of surfactants from groundwater was completed in the field, which simplified sample preservation and reduced the cost of transporting samples.

  10. The effects of nuclear magnetic resonance on patients with cardiac pacemakers

    SciTech Connect

    Pavlicek, W.; Geisinger, M.; Castle, L.; Borkowski, G.P.; Meaney, T.F.; Bream, B.L.; Gallagher, J.H.

    1983-04-01

    The effect of nuclear magnetic resonance (NMR) imaging on six representative cardiac pacemakers was studied. The results indicate that the threshold for initiating the asynchronous mode of a pacemaker is 17 gauss. Radiofrequency levels are present in an NMR unit and may confuse or possibly inhibit demand pacemakers, although sensing circuitry is normally provided with electromagnetic interference discrimination. Time-varying magnetic fields can generate pulse amplitudes and frequencies to mimic cardiac activity. A serious limitation in the possibility of imaging a patient with a pacemaker would be the alteration of normal pulsing parameters due to time-varying magnetic fields.

  11. A potential nuclear magnetic resonance imaging approach for noncontact temperature measurement

    NASA Technical Reports Server (NTRS)

    Manatt, Stanley L.

    1989-01-01

    It is proposed that in a nuclear magnetic resonance (NMR) imaging experiment that it should be possible to measure temperature through an extended volume. The basis for such a measurement would depend upon sensing a temperature dependent on NMR parameter in an inert, volatile molecule (or fluid) filling the volume of interest. Exploratory work suggest that one suitable candidate for such a purpose might be CH3Cl. Possible parameters, other inert gases and feasible measurement schemes that might provide such temperature measurement are discussed.

  12. Cranial anatomy and detection of ischemic stroke in the cat by nuclear magnetic resonance imaging

    SciTech Connect

    Buonanno, F.S.; Pykett, I.L.; Kistler, J.P.; Vielma, J.; Brady, T.J.; Hinshaw, W.S.; Goldman, M.R.; Newhouse, J.H.; Pohost, G.M.

    1982-04-01

    Proton nuclear magnetic resonance (NMR) images of cat heads were obtained using a small, experimental imaging system. As a prelude to the study of experimental ischemic brain infarction, the normal cat head was imaged for identification of anatomical features. Images of one cat which had undergone ligation of the middle cerebral artery three weeks previously showed brain changes associated with chronic ischemic stroke and compared favorably with findings on computed tomography (CT). The NMR images have millimetric spatial resolution. NMR parameters inherent in the tissues provide intensity variations and are sufficiently sensitive to yield contrast resolution surpassing that of CT.

  13. Development of Nuclear Magnetic Resonance Imaging/spectroscopy for improved petroleum recovery. Final report

    SciTech Connect

    Barrufet, M.A.; Flumerfelt, F.W.; Walsh, M.P.; Watson, A.T.

    1994-04-01

    The overall objectives of this program are to develop and apply Nuclear Magnetic Resonance Imaging (NMRI) and CT X-Ray Scanning methods for determining rock, fluid, and petrophysical properties and for fundamental studies of multiphase flow behavior in porous media. Specific objectives are divided into four subtasks: (1) development of NMRI and CT scanning for the determination of rock-fluid and petrophysical properties; (2) development of NMRI and CT scanning for characterizing conventional multiphase displacement processes; (3) development of NMR and CT scanning for characterizing dispersed phase processes; and (4) miscible displacement studies.

  14. Characterization of humic acid fractions by C-13 nuclear magnetic resonance spectroscopy

    USGS Publications Warehouse

    Wershaw, R. L.; Thorn, K.A.; Pinckney, D.J.

    1988-01-01

    Soil humic acids from different environments were fractionated by adsorption chromatography on Sephadex and characterized by C-13 nuclear magnetic resonance (NMR) spectroscopy. The C-13 NMR spectra of the fractions consist of some sharp, well-resolved lines and some broad bands in contrast to the spectra of the unfractionated humic acids, where the bands are broader and less well-resolved. The marked increase in resolution is apparently due to increased homogeneity of the fractions. These spectra are compared to the spectra of model compounds.

  15. Nuclear magnetic resonance spectroscopy of mussel adhesive protein repeating peptide segment.

    PubMed

    Olivieri, M P; Wollman, R M; Alderfer, J L

    1997-12-01

    Mussel adhesive protein (MAP) is the adhesive agent used by the common blue sea mussel (Mytilus edulis) to attach the animal to various underwater surfaces. It is generally composed of 75 to 85 repeating decameric units with the reported primary sequence NH2-Ala(1)-Lyst(2)-Pro(3)-Ser(4)-Tyr(5)-Hyp(6)-Hyp(7)-Thr(8)-DOPA( 9)- Lys(10)-COOH. This study examines this peptide's solution-state conformation using proton nuclear magnetic resonance (NMR) spectroscopy. NMR and molecular modeling of the decamer before and after molecular dynamics calculations in water suggests a conformation that retains an overall bent helix.

  16. Novel rhenium gasket design for nuclear resonant inelastic x-ray scattering at high pressure

    SciTech Connect

    Tanis, Elizabeth A.; Giefers, Hubertus; Nicol, Malcolm F.

    2008-02-15

    For the first time, a highly absorbing element, rhenium, has been proven to be a strong, reliable, and safe gasket material for achieving high pressure in nuclear resonant inelastic x-ray scattering (NRIXS) experiments. Rhenium foil was cut into rectangular slices and in order to reduce absorption, the elevated imprint due to preindenting of the gasket is removed using electrical discharge machining. By utilizing this novel gasket design, transmission losses were mitigated while performing NRIXS experiments conducted on the {sup 119}Sn and {sup 57}Fe Moessbauer isotopes.

  17. Quantitative carbon-13 nuclear magnetic resonance spectroscopic study of mobile residues in bacteriorhodopsin

    SciTech Connect

    Bowers, J.L.; Oldfield, E.

    1988-07-12

    The authors have used quantitative carbon-13 nuclear magnetic resonance (NMR) spectroscopy to study the dynamic structure of the backbone of bacteriorhodopsin in the purple membrane of Halobacterium halobium R/sub 1/ and JW-3. NMR experiments were performed using an internal sucrose quantitation standard on purple membranes in which one of the following /sup 13/C'-labeled amino acids had been biosynthetically incorporated: glycine, isoleucine, lysine, phenylalanine, and valine. The results suggest that the C-terminus of the polypeptide chain backbone, and possibly one of the connecting loops, undergoes rapid, large angle fluctuations. The results are compared with previous NMR and fluorescence spectroscopic data obtained on bacteriorhodopsin.

  18. Nondestructive determination of the 13C content in isotopic diamond by nuclear resonance fluorescence

    NASA Astrophysics Data System (ADS)

    Beck, O.; Ruf, T.; Finkelstein, Y.; Cardona, M.; Anthony, T. R.; Belic, D.; Eckert, T.; Jäger, D.; Kneissl, U.; Maser, H.; Moreh, R.; Nord, A.; Pitz, H. H.; Wolpert, A.

    1998-05-01

    Nuclear resonance fluorescence excited with continuous electron bremsstrahlung from the 4.3 MV Stuttgart Dynamitron accelerator is used as a nondestructive method to determine the 13C content x of bulk isotopic diamonds (12C1-x13Cx). The smallest detectable amount of 13C in carbon or low Z matrices is on the order of 0.5 mg. The relative accuracy of absolute mass determinations is about ±7%. Errors are mainly due to uncertainties in the natural widths Γ of the 13C nuclear levels at 3089 and 3684 keV used in the measurements. The results confirm a previous calibration which is based on Raman scattering and the destructive determination of x by mass spectroscopy.

  19. /sup 13/C nuclear magnetic resonance study of the complexation of calcium by taurine

    SciTech Connect

    Irving, C.S.; Hammer, B.E.; Danyluk, S.S.; Klein, P.D.

    1980-01-01

    /sup 13/C Nuclear magnetic resonance chemical shifts, /sup 1/J/sub c-c/ scalar coupling constants, spin-lattice relaxation times, and nuclear Overhauser effects were determined for taurine-(1, 2 /sup 13/C) and a taurine-(1 /sup 13/C) and taurine-(2 /sup 13/C) mixture in the presence and absence of calcium. Comparison of taurine titration shifts to values for related compounds reveals some unusual electronic properties of the taurine molecule. Stability constants of 1:1 calcium complexes with taurine zwitterions and anions, as well as their /sup 13/C chemical shifts, were obtained by least squares analysis of titration curves measured in the presence of calcium. The stability constants of calcium-taurine complexes were significantly lower than previous values and led to estimates that only approximately one percent of intracellular calcium of mammalian myocardial cells would exist in a taurine complex.

  20. Isoscalar monopole resonance of the alpha particle: a prism to nuclear Hamiltonians.

    PubMed

    Bacca, Sonia; Barnea, Nir; Leidemann, Winfried; Orlandini, Giuseppina

    2013-01-25

    We present an ab initio study of the isoscalar monopole excitations of (4)He using different realistic nuclear interactions, including modern effective field theory potentials. In particular we concentrate on the transition form factor F(M) to the narrow 0(+) resonance close to threshold. F(M) exhibits a strong potential model dependence, and can serve as a kind of prism to distinguish among different nuclear force models. Compared to the measurements obtained from inelastic electron scattering off ^{4}He, one finds that the state-of-the-art theoretical transition form factors are at variance with experimental data, especially in the case of effective field theory potentials. We discuss some possible reasons for such a discrepancy, which still remains a puzzle.

  1. A Search for Nonstandard Neutron Spin Interactions using Dual Species Xenon Nuclear Magnetic Resonance

    NASA Astrophysics Data System (ADS)

    Bulatowicz, Michael; Larsen, Michael; Mirijanian, James; Fu, Changbo; Yan, Haiyang; Smith, Erick; Snow, Mike; Walker, Thad

    2012-06-01

    NMR measurements using polarized noble gases can constrain possible exotic spin-dependent interactions involving nucleons. A differential measurement insensitive to magnetic field fluctuations can be performed using a mixture of two polarized species with different ratios of nucleon spin to magnetic moment. We used the NMR cell test station at Northrop Grumman Corporation (NGC) (developed to evaluate dual species xenon vapor cells for the Nuclear Magnetic Resonance Gyroscope) to search for NMR frequency shifts of xenon-129 and xenon-131 when a non-magnetic zirconia rod is modulated near the NMR cell. We simultaneously excited both Xe isotopes and detected free-induction-decay transients. In combination with theoretical calculations of the neutron spin contribution to the nuclear angular momentum, the measurements put a new upper bound on possible monopole-dipole interactions of the neutron for ranges around 1mm. This work is supported by the NGC Internal Research and Development (IRAD) funding, the Department of Energy, and the NSF.

  2. Interaction of Strain and Nuclear Spins in Silicon: Quadrupolar Effects on Ionized Donors

    NASA Astrophysics Data System (ADS)

    Franke, David P.; Hrubesch, Florian M.; Künzl, Markus; Becker, Hans-Werner; Itoh, Kohei M.; Stutzmann, Martin; Hoehne, Felix; Dreher, Lukas; Brandt, Martin S.

    2015-07-01

    The nuclear spins of ionized donors in silicon have become an interesting quantum resource due to their very long coherence times. Their perfect isolation, however, comes at a price, since the absence of the donor electron makes the nuclear spin difficult to control. We demonstrate that the quadrupolar interaction allows us to effectively tune the nuclear magnetic resonance of ionized arsenic donors in silicon via strain and determine the two nonzero elements of the S tensor linking strain and electric field gradients in this material to S11=1.5 ×1022 V /m2 and S44=6 ×1022 V /m2 . We find a stronger benefit of dynamical decoupling on the coherence properties of transitions subject to first-order quadrupole shifts than on those subject to only second-order shifts and discuss applications of quadrupole physics including mechanical driving of magnetic resonance, cooling of mechanical resonators, and strain-mediated spin coupling.

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

    SciTech Connect

    Urban, Jeffry Todd

    2004-01-01

    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

  4. Zero and Ultra-Low-Field Nuclear Magnetic Resonance Spectroscopy Via Optical Magnetometry

    NASA Astrophysics Data System (ADS)

    Blanchard, John Woodland

    Nuclear magnetic resonance (NMR) is among the most powerful analytical tools available to the chemical and biological sciences for chemical detection, characterization, and structure elucidation. NMR experiments are usually performed in large magnetic fields in order to maximize sensitivity and increase chemical shift resolution. However, the high magnetic fields required for conventional NMR necessitate large, immobile, and expensive superconducting magnets, limiting the use of the technique. New hyperpolarization and non-inductive detection methods have recently allowed for NMR measurements in the inverse regime of extremely low magnetic fields. Whereas a substantial body of research has been conducted in the high-field regime, taking advantage of the efficient coherent control afforded by a spectroscopy dominated by coupling to the spectrometer, the zero- and ultra-low-field (ZULF) regime has remained mostly unexplored. In this dissertation, we investigate the applicability of ZULF-NMR as a novel spectroscopic technique complimentary to high-field NMR. In particular, we consider various aspects of the ZULF-NMR experiment and the dynamics of nuclear spins under various local spin coupling Hamiltonians. We first survey zero-field NMR experiments on systems dominated by the electron-mediated indirect spin-spin coupling (J-coupling). The resulting J-spectra permit precision measurement of chemically relevant information due to the exquisite sensitivity of J-couplings to subtle changes in molecular geometry and electronic structure. We also consider the effects of weak magnetic fields and residual dipolar couplings in anisotropic media, which encode information about nuclear magnetic moments and geometry, and further resolve topological ambiguities by lifting degeneracies. By extending the understanding of the interactions that contribute to ZULF-NMR spectra, this work represents a significant advancement towards a complete description of zero- and ultra

  5. Methodological aspects in the calculation of parity-violating effects in nuclear magnetic resonance parameters.

    PubMed

    Weijo, Ville; Bast, Radovan; Manninen, Pekka; Saue, Trond; Vaara, Juha

    2007-02-21

    We examine the quantum chemical calculation of parity-violating (PV) electroweak contributions to the spectral parameters of nuclear magnetic resonance (NMR) from a methodological point of view. Nuclear magnetic shielding and indirect spin-spin coupling constants are considered and evaluated for three chiral molecules, H2O2, H2S2, and H2Se2. The effects of the choice of a one-particle basis set and the treatment of electron correlation, as well as the effects of special relativity, are studied. All of them are found to be relevant. The basis-set dependence is very pronounced, especially at the electron correlated ab initio levels of theory. Coupled-cluster and density-functional theory (DFT) results for PV contributions differ significantly from the Hartree-Fock data. DFT overestimates the PV effects, particularly with nonhybrid exchange-correlation functionals. Beginning from third-row elements, special relativity is of importance for the PV NMR properties, shown here by comparing perturbational one-component and various four-component calculations. In contrast to what is found for nuclear magnetic shielding, the choice of the model for nuclear charge distribution--point charge or extended (Gaussian)--has a significant impact on the PV contribution to the spin-spin coupling constants. PMID:17328593

  6. Hybrid quadrupole excitons and polaritons in cuprous oxide

    NASA Astrophysics Data System (ADS)

    Roslyak, Oleksiy

    In this thesis I consider novel type of materials such as hybrid organic/inorganic heteoro-structures and polystyrene micro-spheres/inorganic composites. The organic/inorganic compound is presented by DCM2:CA:PS/cuprous oxide material. Using "solid state solvent" mechanism I propose to bring the Frenkel exciton (FE) of the DCM2 into resonance with 1S quadrupole Wanier-Mott exciton (WE) in cuprous oxide. This two types of the excitons form new type of quadrupole-dipole hybrid exciton. This hybrid is characterized by long lifetime and big oscillator strength inherited from the organic FE. In the part I of the thesis I investigate the enhancement of the quadrupole properties generic to cuprous oxide exciton by means of such resonant hybridization. I consider enhancement of photo-thermal bi-stability and second harmonic generation. The second part is devoted to the problems of light-matter interaction in cuprous oxide crystals such as weak interaction with LA phonons and whispering gallery modes (WGM) in adjacent layer of polystyrene micro-spheres. While the first effect is likely to impeded BEC of the polaritons, the second mechanism provides necessary temporal coherence. It is possible by trapping the light part of the polariton into resonant WGM through big gradient of the evanescent tail which provides big lifetime of such evanescent polariton. Due to big gradient of the evanescent field it couples "naturally" to the quadrupole WE in cuprous oxide.

  7. Solid state nuclear magnetic resonance with magic-angle spinning and dynamic nuclear polarization below 25 K.

    PubMed

    Thurber, Kent R; Potapov, Alexey; Yau, Wai-Ming; Tycko, Robert

    2013-01-01

    We describe an apparatus for solid state nuclear magnetic resonance (NMR) with dynamic nuclear polarization (DNP) and magic-angle spinning (MAS) at 20-25 K and 9.4 Tesla. The MAS NMR probe uses helium to cool the sample space and nitrogen gas for MAS drive and bearings, as described earlier, but also includes a corrugated waveguide for transmission of microwaves from below the probe to the sample. With a 30 mW circularly polarized microwave source at 264 GHz, MAS at 6.8 kHz, and 21 K sample temperature, greater than 25-fold enhancements of cross-polarized (13)C NMR signals are observed in spectra of frozen glycerol/water solutions containing the triradical dopant DOTOPA-TEMPO when microwaves are applied. As demonstrations, we present DNP-enhanced one-dimensional and two-dimensional (13)C MAS NMR spectra of frozen solutions of uniformly (13)C-labeled l-alanine and melittin, a 26-residue helical peptide that we have synthesized with four uniformly (13)C-labeled amino acids. PMID:23238592

  8. Prospects for Sub-Micron Solid State Nuclear Magnetic Resonance Imaging with Low-Temperature Dynamic Nuclear Polarization

    PubMed Central

    Thurber, Kent R.; Tycko, Robert

    2010-01-01

    Summary We evaluate the feasibility of 1H nuclear magnetic resonance (NMR) imaging with sub-micron voxel dimensions using a combination of low temperatures and dynamic nuclear polarization (DNP). Experiments are performed on nitroxide-doped glycerol/water at 9.4 T and temperatures below 40 K, using a 30 mW tunable microwave source for DNP. With DNP at 7 K, a 0.5 µl sample yields a 1H NMR signal-to-noise ratio of 770 in two scans with pulsed spin-lock detection and after 80 db signal attenuation. With reasonable extrapolations, we infer that 1H NMR signals from 1 µm3 voxel volumes should be readily detectable, and voxels as small as 0.03 µm3 may eventually be detectable. Through homonuclear decoupling with a frequency-switched Lee-Goldburg spin echo technique, we obtain 830 Hz 1H NMR linewidths at low temperatures, implying that pulsed field gradients equal to 0.4 G/d or less would be required during spatial encoding dimensions of an imaging sequence, where d is the resolution in each dimension. PMID:20458431

  9. Solid state nuclear magnetic resonance with magic-angle spinning and dynamic nuclear polarization below 25 K

    NASA Astrophysics Data System (ADS)

    Thurber, Kent R.; Potapov, Alexey; Yau, Wai-Ming; Tycko, Robert

    2013-01-01

    We describe an apparatus for solid state nuclear magnetic resonance (NMR) with dynamic nuclear polarization (DNP) and magic-angle spinning (MAS) at 20-25 K and 9.4 Tesla. The MAS NMR probe uses helium to cool the sample space and nitrogen gas for MAS drive and bearings, as described earlier [1], but also includes a corrugated waveguide for transmission of microwaves from below the probe to the sample. With a 30 mW circularly polarized microwave source at 264 GHz, MAS at 6.8 kHz, and 21 K sample temperature, greater than 25-fold enhancements of cross-polarized 13C NMR signals are observed in spectra of frozen glycerol/water solutions containing the triradical dopant DOTOPA-TEMPO when microwaves are applied. As demonstrations, we present DNP-enhanced one-dimensional and two-dimensional 13C MAS NMR spectra of frozen solutions of uniformly 13C-labeled L-alanine and melittin, a 26-residue helical peptide that we have synthesized with four uniformly 13C-labeled amino acids.

  10. Comparative Definitions for Moderate-Severe Ischemia in Stress Nuclear, Echocardiography, and Magnetic Resonance Imaging

    PubMed Central

    Shaw, Leslee J.; Berman, Daniel S.; Picard, Michael H.; Friedrich, Matthias G.; Kwong, Raymond Y.; Stone, Gregg W.; Senior, Roxy; Min, James K.; Hachamovitch, Rory; Scherrer-Crosbie, Marielle; Mieres, Jennifer H.; Marwick, Thomas H.; Phillips, Lawrence M.; Chaudhry, Farooq A.; Pellikka, Patricia A.; Slomka, Piotr; Arai, Andrew E.; Iskandrian, Ami E.; Bateman, Timothy M.; Heller, Gary V.; Miller, Todd D.; Nagel, Eike; Goyal, Abhinav; Borges-Neto, Salvador; Boden, William E.; Reynolds, Harmony R.; Hochman, Judith S.; Maron, David J.; Douglas, Pamela S.

    2014-01-01

    The lack of standardized reporting of the magnitude of ischemia on noninvasive imaging contributes to variability in translating the severity of ischemia across stress imaging modalities. We identified the risk of coronary artery disease (CAD) death or myocardial infarction (MI) associated with ≥10% ischemic myocardium on stress nuclear imaging as the risk threshold for stress echocardiography and cardiac magnetic resonance. A narrative review revealed that ≥10% ischemic myocardium on stress nuclear imaging was associated with a median rate of CAD death or MI of 4.9%/year (interquartile range: 3.75% to 5.3%). For stress echocardiography, ≥3 newly dysfunctional segments portend a median rate of CAD death or MI of 4.5%/year (interquartile range: 3.8% to 5.9%). Although imprecisely delineated, moderate-severe ischemia on cardiac magnetic resonance may be indicated by ≥4 of 32 stress perfusion defects or ≥3 dobutamine-induced dysfunctional segments. Risk-based thresholds can define equivalent amounts of ischemia across the stress imaging modalities, which will help to translate a common understanding of patient risk on which to guide subsequent management decisions. PMID:24925328

  11. High-sensitivity cooled coil system for nuclear magnetic resonance in kHz range

    SciTech Connect

    Lin, Tingting; Zhao, Jing; Zhang, Yi; Krause, Hans-Joachim; Lee, Yong-Ho; Lin, Jun

    2014-11-15

    In several low-field Nuclear Magnetic Resonance (LF-NMR) and surface nuclear magnetic resonance applications, i.e., in the frequency range of kHz, high sensitivity magnetic field detectors are needed. Usually, low-T{sub c} superconducting quantum interference devices (SQUIDs) with a high field sensitivity of about 1 fT/Hz{sup 1/2} are employed as detectors. Considering the flux trapping and operational difficulties associated with low-T{sub c} SQUIDs, we designed and fabricated liquid-nitrogen-cooled Cu coils for NMR detection in the kHz range. A cooled coil system consisting of a 9-cm diameter Cu coil and a low noise preamplifier was systematically investigated and reached a sensitivity of 2 fT/Hz{sup 1/2} at 77 K, which is 3 times better compared to the sensitivity at 300 K. A Q-switch circuit as an essential element for damping the ringing effects of the pickup coil was developed to acquire free induction decay signals of a water sample with minimum loss of signal. Our studies demonstrate that cooled Cu coils, if designed properly, can provide a comparable sensitivity to low-T{sub c} SQUIDs.

  12. Investigation of enzymatic C-P bond formation using multiple quantum HCP nuclear magnetic resonance spectroscopy.

    PubMed

    Hu, Kaifeng; Werner, Williard J; Allen, Kylie D; Wang, Susan C

    2015-04-01

    The biochemical mechanism for the formation of the C-P-C bond sequence found in l-phosphinothricin, a natural product with antibiotic and herbicidal activity, remains unclear. To obtain further insight into the catalytic mechanism of PhpK, the P-methyltransferase responsible for the formation of the second C-P bond in l-phosphinothricin, we utilized a combination of stable isotopes and two-dimensional nuclear magnetic resonance spectroscopy. Exploiting the newly emerged Bruker QCI probe (Bruker Corp.), we specifically designed and ran a (13) C-(31) P multiple quantum (1) H-(13) C-(31) P (HCP) experiment in (1) H-(31) P two-dimensional mode directly on a PhpK-catalyzed reaction mixture using (13) CH3 -labeled methylcobalamin as the methyl group donor. This method is particularly advantageous because minimal sample purification is needed to maximize product visualization. The observed 3:1:1:3 multiplet specifically and unequivocally illustrates direct bond formation between (13) CH3 and (31) P. Related nuclear magnetic resonance experiments based upon these principles may be designed for the study of enzymatic and/or synthetic chemical reaction mechanisms.

  13. Citrate and Sugar Cofermentation in Leuconostoc oenos, a (sup13)C Nuclear Magnetic Resonance Study

    PubMed Central

    Ramos, A.; Santos, H.

    1996-01-01

    (sup13)C nuclear magnetic resonance spectroscopy was used to investigate citrate-glucose cometabolism in nongrowing cell suspensions of the wine lactic acid bacterium Leuconostoc oenos. The use of isotopically enriched substrates allowed us to identify and quantify in the end products the carbon atoms derived from each of the substrates supplied; furthermore, it was possible to differentiate between products derived from the metabolism of endogenous carbon reserves and those derived from external substrates. Citrate-sugar cometabolism was also monitored in dilute cell suspensions for comparison with the nuclear magnetic resonance results. A clear metabolic shift of the end products from glucose metabolism was observed when citrate was provided along with glucose: ethanol was replaced by acetate, and 2,3-butanediol was produced. Reciprocally, the production of lactate and 2,3-butanediol from citrate was increased in the presence of glucose. When citrate was cometabolized with glucose, a 10-fold reduction in the intracellular concentration of glucose-6-phosphate was observed, a result in line with the observed citrate-induced stimulation of glucose consumption. The presence of citrate provided additional pathways for NADP(sup+) regeneration and allowed the diversion of sugar carbon to reactions in which ATP was synthesized. The increased growth rates and maximal biomass yields of L. oenos growing on citrate-glucose mixtures resulted from increased ATP synthesis both by substrate-level phosphorylation and by a chemiosmotic mechanism. PMID:16535363

  14. High-Gradient Nanomagnets on Cantilevers for Sensitive Detection of Nuclear Magnetic Resonance

    PubMed Central

    Longenecker, Jonilyn G.; Mamin, H. J.; Senko, Alexander W.; Chen, Lei; Rettner, Charles T.; Rugar, Daniel; Marohn, John A.

    2012-01-01

    Detection of magnetic resonance as a force between a magnetic tip and nuclear spins has previously been shown to enable sub-10 nm resolution 1H imaging. Maximizing the spin force in such a magnetic resonance force microscopy (MRFM) experiment demands a high field gradient. In order to study a wide range of samples, it is equally desirable to locate the magnetic tip on the force sensor. Here we report the development of attonewton-sensitivity cantilevers with high gradient cobalt nanomagnet tips. The damage layer thickness and saturation magnetization of the magnetic material were characterized by X-ray photoelectron spectroscopy and superconducting quantum interference device magnetometry. The coercive field and saturation magnetization of an individual tip were quantified in situ using frequency-shift cantilever magnetometry. Measurements of cantilever dissipation versus magnetic field and tip-sample separation were conducted. MRFM signals from protons in a polystyrene film were studied versus rf irradiation frequency and tip-sample separation, and from this data the tip field and tip-field gradient were evaluated. Magnetic tip performance was assessed by numerically modeling the frequency dependence of the magnetic resonance signal. We observed a tip-field gradient ∂Bztip∕∂z estimated to be between 4.4 and 5.4 MT m−1, which is comparable to the gradient used in recent 4 nm resolution 1H imaging experiments and larger by nearly an order of magnitude than the gradient achieved in prior magnet-on-cantilever MRFM experiments. PMID:23033869

  15. Redox-dependent structure change and hyperfine nuclear magnetic resonance shifts in cytochrome c

    SciTech Connect

    Feng, Yiquing; Roder, H.; Englander, S.W. )

    1990-04-10

    Proton nuclear magnetic resonance assignments for reduced and oxidized equine cytochrome c show that many individual protons exhibit different chemical shifts in the two protein forms, reflecting diamagnetic shift effects due to structure change, and in addition contact and pseudocontact shifts that occur only in the paramagnetic oxidized form. To evaluate the chemical shift differences for structure change, the authors removed the pseudocontact shift contribution by a calculation based on knowledge of the electron spin g tensor. The g-tensor calculation, when repeated using only 12 available C{sub {alpha}}H proton resonances for cytochrom c from tuna, proved to be remarkably stable. The derived g tensor was then used together with spatial coordinates for the oxidized form to calculate the pseudocontact shift contribution to proton resonances at 400 identifiable sites throughout the protein, so that the redox-dependent chemical shift discrepancy, could be evaluated. Large residual changes in chemical shift define the Fermi contact shifts, where are found as expected to be limited to the immediate covalent structure of the heme and its ligands and to be asymmetrically distributed over the heme. The chemical shift discrepancies observed appear in the main to reflect structure-dependent diamagnetic shifts rather than hyperfine effects due to displacements in the pseudocontact shift field. Although 51 protons in 29 different residues exhibit significant chemical shift changes, the general impressions one of small structural adjustments to redox-dependent strain rather than sizeable structural displacements or rearrangements.

  16. A deuterium and carbon nuclear magnetic resonance spectroscopic investigation of blood flow and carbohydrate metabolism

    SciTech Connect

    Bosch, C.S.E.

    1988-01-01

    The purpose of this study is the development and application of nuclear magnetic resonance (NMR) spectroscopic techniques for this study of whole tissue metabolism, tissue perfusion and blood flow. The feasibility of spin imaging deuterium-enriched tissue water is demonstrated in cat brain in vivo and in situ. The potential application of D{sub 2}O administration to deuterium-flow-imaging is considered. NMR investigations of hepatic carbohydrate metabolism were performed in rat liver in vivo and in situ. A coaxial, double-surface-coil, double-resonance probe was developed for carbon detection while decoupling neighboring proton scalar interactions ({sup 13}C-({sup 1}H)) in hepatic tissue within the living animal. Hormonal and substrate regulation of hepatic glucose and glycogen metabolism was investigated by monitoring the metabolic fate of an administered c-dose of (1-{sup 13}C)glucose. Label flux was directed primarily into newly-synthesized {sup 13}C-labeled glycogen. A multiple resonance ({sup 1}H, {sup 13}C, {sup 31}P) liver perfusion probe was designed for complimentary carbohydrate metabolic studies in rat liver in vitro. A description of the {sup 13}C-({sup 1}H)/{sup 31}P NMR perfusion probe is given. The surgical technique used for liver excision and peripheral life-support apparatus required to maintain hepatic function are also detailed.

  17. A smoothing monotonic convergent optimal control algorithm for nuclear magnetic resonance pulse sequence design

    NASA Astrophysics Data System (ADS)

    Maximov, Ivan I.; Salomon, Julien; Turinici, Gabriel; Nielsen, Niels Chr.

    2010-02-01

    The past decade has demonstrated increasing interests in using optimal control based methods within coherent quantum controllable systems. The versatility of such methods has been demonstrated with particular elegance within nuclear magnetic resonance (NMR) where natural separation between coherent and dissipative spin dynamics processes has enabled coherent quantum control over long periods of time to shape the experiment to almost ideal adoption to the spin system and external manipulations. This has led to new design principles as well as powerful new experimental methods within magnetic resonance imaging, liquid-state and solid-state NMR spectroscopy. For this development to continue and expand, it is crucially important to constantly improve the underlying numerical algorithms to provide numerical solutions which are optimally compatible with implementation on current instrumentation and at same time are numerically stable and offer fast monotonic convergence toward the target. Addressing such aims, we here present a smoothing monotonically convergent algorithm for pulse sequence design in magnetic resonance which with improved optimization stability lead to smooth pulse sequence easier to implement experimentally and potentially understand within the analytical framework of modern NMR spectroscopy.

  18. A smoothing monotonic convergent optimal control algorithm for nuclear magnetic resonance pulse sequence design.

    PubMed

    Maximov, Ivan I; Salomon, Julien; Turinici, Gabriel; Nielsen, Niels Chr

    2010-02-28

    The past decade has demonstrated increasing interests in using optimal control based methods within coherent quantum controllable systems. The versatility of such methods has been demonstrated with particular elegance within nuclear magnetic resonance (NMR) where natural separation between coherent and dissipative spin dynamics processes has enabled coherent quantum control over long periods of time to shape the experiment to almost ideal adoption to the spin system and external manipulations. This has led to new design principles as well as powerful new experimental methods within magnetic resonance imaging, liquid-state and solid-state NMR spectroscopy. For this development to continue and expand, it is crucially important to constantly improve the underlying numerical algorithms to provide numerical solutions which are optimally compatible with implementation on current instrumentation and at same time are numerically stable and offer fast monotonic convergence toward the target. Addressing such aims, we here present a smoothing monotonically convergent algorithm for pulse sequence design in magnetic resonance which with improved optimization stability lead to smooth pulse sequence easier to implement experimentally and potentially understand within the analytical framework of modern NMR spectroscopy. PMID:20192290

  19. A Spectrometer for Dynamic Nuclear Polarization and Electron Paramagnetic Resonance at High Frequencies

    NASA Astrophysics Data System (ADS)

    Becerra, L. R.; Gerfen, G. J.; Bellew, B. F.; Bryant, J. A.; Hall, D. A.; Inati, S. J.; Weber, R. T.; Un, S.; Prisner, T. F.; McDermott, A. E.; Fishbein, K. W.; Kreischer, K. E.; Temkin, R. J.; Singel, D. J.; Griffin, R. G.

    A high-frequency dynamic nuclear polarization (DNP)/electron paramagnetic resonance spectrometer operating at 211 MHz for 1H and 140 GHz for g= 2 paramagnetic centers (5 T static field) is described. The salient feature of the instrument is a cyclotron-resonance maser (gyrotron) which generates high-frequency, high-power microwave radiation. This gyrotron, which under conventional operation produces millisecond pulses at kilowatt powers, has been adapted to operate at ˜100 W for 1 to 20 s pulses and in the continuous wave mode at the 10 W power level. Experiments combining DNP with magic-angle spinning (MAS) nuclear magnetic resonance were performed on samples consisting of 2% by weight of the free radical BDPA doped into polystyrene. Room-temperature DNP enhancement factors of 10 for 1H and 40 for 13C were obtained in the NMR-MAS spectra. Static DNP NMR has also been performed on samples containing nitroxides dissolved in water:glycerol solvent mixtures. Enhancements of approximately 200 have been obtained for low-temperature (14 K) 1H NMR. A pulsed/CW EPR spectrometer operating at 140 GHz has been developed in conjunction with the DNP spectrometer. Microwave sources include Gunn-diode oscillators which provide low-power (20 mW) radiation, and the gyrotron, which has been used to deliver higher power levels in pulsed experiments. Results using this spectrometer are presented for continuous-wave and echo-detected EPR, electron spin-echo-envelope modulation (ESEEM), and Fourier-transform EPR.

  20. Nuclear Resonance Scattering of Synchrotron Radiation as a Unique Electronic, Structural, and Thermodynamic Probe

    NASA Astrophysics Data System (ADS)

    Alp, E. Ercan; Sturhahn, Wolfgang; Toellner, Thomas S.; Zhao, Jiyong; Leu, Bogdan M.

    Discovery of Mössbauer effect [1] in a nuclear transition was a remarkable development. It revealed how long-lived nuclear states with relatively low energies in the kiloelectron volt (keV) region can be excited without recoil. This new effect had a unique feature involving a coupling between nuclear physics and solid-state physics, both in terms of physics and sociology. Physics coupling originates from the fact that recoilless emission and absorption or resonance is only possible if the requirement that nuclei have to be bound in a lattice with quantized vibrational states is fulfilled, and that the finite electron density on the nucleus couples to nuclear degrees of freedom leading to hyperfine interactions. Thus, Mössbauer spectroscopy allows peering into solid-state effects using unique nuclear transitions. Sociological aspects of this coupling had been equally startling and fruitful. The interaction between diverse scientific communities, who learned to use Mössbauer spectroscopy proved to be very valuable. For example, biologists, geologists, chemists, physicists, materials scientists, and archeologists, all sharing a common spectroscopic technique, also learned to appreciate the beauty and intricacies of each other's fields. As a laboratory-based technique, Mössbauer spectroscopy matured by the end of the 1970s. Further exciting developments took place when accelerator-based techniques were employed, like synchrotron radiation or "in-beam" Mössbauer experiments with implanted radioactive ions. More recently, two Mössbauer spectrometers on the surface of the Mars kept the technique vibrant and viable up until present time.